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[ { "docid": "5824985", "text": "BACKGROUND Bariatric surgery is becoming a more widespread treatment for obesity. Comprehensive evidence of the long-term effects of contemporary surgery on a broad range of clinical outcomes in large populations treated in routine clinical practice is lacking. The objective of this study was to measure the association between bariatric surgery, weight, body mass index, and obesity-related co-morbidities. \n METHODS AND FINDINGS This was an observational retrospective cohort study using data from the United Kingdom Clinical Practice Research Datalink. All 3,882 patients registered in the database and with bariatric surgery on or before 31 December 2014 were included and matched by propensity score to 3,882 obese patients without surgery. The main outcome measures were change in weight and body mass index over 4 y; incident diagnoses of type 2 diabetes mellitus (T2DM), hypertension, angina, myocardial infarction (MI), stroke, fractures, obstructive sleep apnoea, and cancer; mortality; and resolution of hypertension and T2DM. Weight measures were available for 3,847 patients between 1 and 4 mo, 2,884 patients between 5 and 12 mo, and 2,258 patients between 13 and 48 mo post-procedure. Bariatric surgery patients exhibited rapid weight loss for the first four postoperative months, at a rate of 4.98 kg/mo (95% CI 4.88-5.08). Slower weight loss was sustained to the end of 4 y. Gastric bypass (6.56 kg/mo) and sleeve gastrectomy (6.29 kg/mo) were associated with greater initial weight reduction than gastric banding (2.77 kg/mo). Protective hazard ratios (HRs) were detected for bariatric surgery for incident T2DM, 0.68 (95% CI 0.55-0.83); hypertension, 0.35 (95% CI 0.27-0.45); angina, 0.59 (95% CI 0.40-0.87);MI, 0.28 (95% CI 0.10-0.74); and obstructive sleep apnoea, 0.55 (95% CI 0.40-0.87). Strong associations were found between bariatric surgery and the resolution of T2DM, with a HR of 9.29 (95% CI 6.84-12.62), and between bariatric surgery and the resolution of hypertension, with a HR of 5.64 (95% CI 2.65-11.99). No association was detected between bariatric surgery and fractures, cancer, or stroke. Effect estimates for mortality found no protective association with bariatric surgery overall, with a HR of 0.97 (95% CI 0.66-1.43). The data used were recorded for the management of patients in primary care and may be subject to inaccuracy, which would tend to lead to underestimates of true relative effect sizes. \n CONCLUSIONS Bariatric surgery as delivered in the UK healthcare system is associated with dramatic weight loss, sustained at least 4 y after surgery. This weight loss is accompanied by substantial improvements in pre-existing T2DM and hypertension, as well as a reduced risk of incident T2DM, hypertension, angina, MI, and obstructive sleep apnoea. Widening the availability of bariatric surgery could lead to substantial health benefits for many people who are morbidly obese.", "title": "Bariatric Surgery in the United Kingdom: A Cohort Study of Weight Loss and Clinical Outcomes in Routine Clinical Care." } ]

[ { "docid": "7627167", "text": "BACKGROUND The objective of this study was to evaluate the effectiveness of a brief, 4-session cognitive behavioral, group psychotherapy for binge eating among bariatric surgery candidates at an academic medical center. Binge eating behaviors have been linked to poorer outcomes among bariatric surgery patients, and binge eating disorder have be considered a contraindication in surgery programs, some of which have mandated preoperative binge eating treatment. However, no previous studies have examined whether a preoperative binge eating intervention could successfully reduce binge eating behaviors among severely obese bariatric surgery candidates. \n METHODS A total of 243 bariatric surgery candidates completed a brief cognitive behavioral group treatment for binge eating behaviors and were administered the Binge Eating Scale and reported the number of weekly binge eating episodes at the initial psychological evaluation and again after the group sessions. The study used a pre-post intervention design. \n RESULTS The results suggested significant reductions in both binge eating behaviors and cognitions and binge eating episodes after the group intervention. The intervention's effectiveness did not differ according to gender or ethnicity (black versus white). \n CONCLUSION A brief cognitive behavioral intervention can reduce binge eating behaviors among bariatric surgery candidates. Given the potential influence of binge eating on outcomes, bariatric surgery programs could benefit by treating binge eating before surgery.", "title": "Brief, four-session group CBT reduces binge eating behaviors among bariatric surgery candidates." }, { "docid": "18872233", "text": "IMPORTANCE Bariatric surgery is associated with sustained weight loss and improved physical health status for severely obese individuals. Mental health conditions may be common among patients seeking bariatric surgery; however, the prevalence of these conditions and whether they are associated with postoperative outcomes remains unknown. \n OBJECTIVE To determine the prevalence of mental health conditions among bariatric surgery candidates and recipients, to evaluate the association between preoperative mental health conditions and health outcomes following bariatric surgery, and to evaluate the association between surgery and the clinical course of mental health conditions. \n DATA SOURCES We searched PubMed, MEDLINE on OVID, and PsycINFO for studies published between January 1988 and November 2015. Study quality was assessed using an adapted tool for risk of bias; quality of evidence was rated based on GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. \n FINDINGS We identified 68 publications meeting inclusion criteria: 59 reporting the prevalence of preoperative mental health conditions (65,363 patients) and 27 reporting associations between preoperative mental health conditions and postoperative outcomes (50,182 patients). Among patients seeking and undergoing bariatric surgery, the most common mental health conditions, based on random-effects estimates of prevalence, were depression (19% [95% CI, 14%-25%]) and binge eating disorder (17% [95% CI, 13%-21%]). There was conflicting evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Neither depression nor binge eating disorder was consistently associated with differences in weight outcomes. Bariatric surgery was, however, consistently associated with postoperative decreases in the prevalence of depression (7 studies; 8%-74% decrease) and the severity of depressive symptoms (6 studies; 40%-70% decrease). \n CONCLUSIONS AND RELEVANCE Mental health conditions are common among bariatric surgery patients-in particular, depression and binge eating disorder. There is inconsistent evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Moderate-quality evidence supports an association between bariatric surgery and lower rates of depression postoperatively.", "title": "Mental Health Conditions Among Patients Seeking and Undergoing Bariatric Surgery: A Meta-analysis." }, { "docid": "29022271", "text": "Psychosocial factors have significant potential to affect long-term outcomes of bariatric surgery, including emotional adjustment, adherence to the recommended postoperative lifestyle regimen, weight loss outcomes, and co-morbidity improvement and or resolution. Thus, it is recommended that bariatric behavioral health clinicians with specialized knowledge and experience be involved in the evaluation and care of patients both before and after surgery. The evaluating clinician plays a number of important roles in the multidisciplinary treatment of the bariatric patient. Central among these is the role of identifying factors that may pose challenges to optimal surgical outcome and providing recommendations to the patient and bariatric team on how to address these issues. This document outlines recommendations for the psychosocial evaluation of bariatric surgery patients, appropriate qualifications of those conducting these evaluations, communication of evaluation results and suggested treatment plan, and the extension of behavioral healthcare of the bariatric patient to the entire span of the surgical and postsurgical process.", "title": "Recommendations for the presurgical psychosocial evaluation of bariatric surgery patients." }, { "docid": "43220289", "text": "Extreme obesity is associated with severe psychiatric and somatic comorbidity and impairment of psychosocial functioning. Bariatric surgery is the most effective treatment not only with regard to weight loss but also with obesity-associated illnesses. Health-related psychological and psychosocial variables have been increasingly considered as important outcome variables of bariatric surgery. However, the long-term impact of bariatric surgery on psychological and psychosocial functioning is largely unclear. The aim of this study was to evaluate the relationship between the course of weight and psychological variables including depression, anxiety, health-related quality of life (HRQOL), and self-esteem up to 4 years after obesity surgery. By standardized questionnaires prior to (T1) and 1 year (T2), 2 years (T3), and 4 years (T4) after surgery, 148 patients (47 males (31.8 %), 101 females (68.2 %), mean age 38.8 ± 10.2 years) were assessed. On average, participants lost 24.6 % of their initial weight 1 year after surgery, 25.1 % after 2 years, and 22.3 % after 4 years. Statistical analysis revealed significant improvements in depressive symptoms, physical dimension of quality of life, and self-esteem with peak improvements 1 year after surgery. These improvements were largely maintained. Significant correlations between weight loss and improvements in depression, physical aspects of HRQOL (T2, T3, and T4), and self-esteem (T3) were observed. Corresponding to the considerable weight loss after bariatric surgery, important aspects of mental health improved significantly during the 4-year follow-up period. However, parallel to weight regain, psychological improvements showed a slow but not significant decline over time.", "title": "Psychological Outcome 4 Years after Restrictive Bariatric Surgery" }, { "docid": "40949706", "text": "Obesity affects 32% of adults in the USA. Surgery generates substantial weight loss, but 20–30% fails to achieve successful weight loss. Our objective was to identify preoperative psychosocial factors associated with weight loss following bariatric surgery. We performed a literature search of PubMed® and the Cochrane Database of Reviews of Effectiveness between 1988 and April 2010. Articles were screened for bariatric surgery and weight loss if they included a preoperative predictor of weight loss: body mass index (BMI), preoperative weight loss, eating disorders, or psychiatric disorder/substance abuse. One thousand seven titles were reviewed, 534 articles screened, and 115 included in the review. Factors that may be positively associated with weight loss after surgery include mandatory preoperative weight loss (7 of 14 studies with positive association). Factors that may be negatively associated with weight loss include preoperative BMI (37 out of 62 studies with negative association), super-obesity (24 out of 33 studies), and personality disorders (7 out of 14 studies). Meta-analysis revealed a decrease of 10.1% excess weight loss (EWL) for super-obese patients (95% confidence interval (CI) [3.7–16.5%]), though there was significant heterogeneity in the meta-analysis, and an increase of 5.9% EWL for patients with binge eating at 12 months after surgery (95% CI [1.9–9.8%]). Further studies are necessary to investigate whether preoperative factors can predict a clinically meaningful difference in weight loss after bariatric surgery. The identification of predictive factors may improve patient selection and help develop interventions targeting specific needs of patients.", "title": "Preoperative Predictors of Weight Loss Following Bariatric Surgery: Systematic Review" }, { "docid": "19071857", "text": "Pre-operative psychological assessment is recommended by international guidelines for bariatric surgery candidates. Thereby, service teams caring for bariatric patients should include at least one mental health provider (e.g., a psychologist or psychiatrist). The objective of this study was to evaluate the psychology and psychiatry resources and practices in the 37 specialized obesity centers (CSOs) created by the French Ministry of Health. CSO coordinators were contacted by e-mail to collect general information on the centers (e.g., number of bariatric operations). Secondly, psychologists and psychiatrists of each center completed an anonymous questionnaire assessing their professional practices and their organization of care pathways. The vast majority of CSO coordinators (81%, n = 26/32) answered our survey. These results show significant differences and shortages in terms of the psychology/psychiatry resources available. Most of the psychologists (n = 26/31) and psychiatrists (n = 10/10) stated that they systematically meet new patients only before surgery (56%) or both before and after the operation (30%); however, some psychologists and psychiatrists (14%) do not systematically meet all the patients (before and/or after surgery). Nevertheless, all the professionals provide psychology assessments, and about 75% of them offer a psychological follow-up, indicating a similarity regarding the practices of psychologists and psychiatrists. Our results highlight the place of psychological/psychiatric evaluations in French CSOs and emphasize the absence of mental health providers in several of these services. Post-operative psychological follow-up is not usually provided. It would be appropriate to create clear recommendations for post-operative psychological or psychiatric long-term follow-up.", "title": "Mental Health Support Provided Throughout the Bariatric Surgery Clinical Pathway in French Specialized Care Centers for Obesity" }, { "docid": "16390264", "text": "OBJECTIVES To determine the extent to which type of hospital admission (emergency compared with elective) and surgical procedure varied by socioeconomic circumstances, age, sex, and year of admission for colorectal, breast, and lung cancer. \n DESIGN Repeated cross sectional study with data from individual patients, 1 April 1999 to 31 March 2006. \n SETTING Hospital episode statistics (HES) dataset. \n PARTICIPANTS 564 821 patients aged 50 and over admitted with a diagnosis of colorectal, breast, or lung cancer. \n MAIN OUTCOME MEASURES Proportion of patients admitted as emergencies, and the proportion receiving the recommended surgical treatment. \n RESULTS Patients from deprived areas, older people, and women were more likely to be admitted as emergencies. For example, the adjusted odds ratio for patients with breast cancer in the least compared with most deprived fifth of deprivation was 0.63 (95% confidence interval 0.60 to 0.66) and the adjusted odds ratio for patients with lung cancer aged 80-89 compared with those aged 50-59 was 3.13 (2.93 to 3.34). There were some improvements in disparities between age groups but not for patients living in deprived areas over time. Patients from deprived areas were less likely to receive preferred procedures for rectal, breast, and lung cancer. These findings did not improve with time. For example, 67.4% (3529/5237) of patients in the most deprived fifth of deprivation had anterior resection for rectal cancer compared with 75.5% (4497/5959) of patients in the least deprived fifth (1.34, 1.22 to 1.47). Over half (54.0%, 11 256/20 849) of patients in the most deprived fifth of deprivation had breast conserving surgery compared with 63.7% (18 445/28 960) of patients in the least deprived fifth (1.21, 1.16 to 1.26). Men were less likely than women to undergo anterior resection and lung cancer resection and older people were less likely to receive breast conserving surgery and lung cancer resection. For example, the adjusted odds ratio for lung cancer patients aged 80-89 compared with those aged 50-59 was 0.52 (0.46 to 0.59). Conclusions Despite the implementation of the NHS Cancer Plan, social factors still strongly influence access to and the provision of care.", "title": "Social variations in access to hospital care for patients with colorectal, breast, and lung cancer between 1999 and 2006: retrospective analysis of hospital episode statistics" }, { "docid": "24980622", "text": "PURPOSE To investigate hypoxia measured by pimonidazole binding, glucose transporter 1 (GLUT1) and carbonic anhydrase IX (CA-IX) expression, proliferation, and vascularity in liver metastases of colorectal cancer and to compare GLUT1 and CA-IX expression in corresponding primary tumors. \n METHODS AND MATERIALS Twenty-five patients with liver metastases of colorectal cancer, planned for metastasectomy, were included. The hypoxia marker pimonidazole and proliferation marker iododeoxyuridine were administered before surgery. After immunofluorescent staining of the frozen metastases, pimonidazole binding, vascularity, and proliferation were analyzed quantitatively. Thirteen paraffin-embedded primary tumors were stained immunohistochemically for GLUT1 and CA-IX expression, which was analyzed semiquantitatively in primary tumors and corresponding liver metastases. \n RESULTS In liver metastases, pimonidazole binding showed a pattern consistent with diffusion-limited hypoxia. The mean pimonidazole-positive fraction was 0.146; the mean distance from vessels to pimonidazole-positive areas was 80 microm. When expressed, often co-localization was observed between pimonidazole binding and GLUT1 or CA-IX expression, but microregional areas of mismatch were also observed. No correlation between the level of pimonidazole binding and GLUT1 or CA-IX expression was observed. In some patients, a large fraction (up to 30%) of proliferating cells was present in pimonidazole-stained areas. Expression of CA-IX in primary tumors and metastases showed a significant correlation, which was absent for GLUT1 expression. \n CONCLUSIONS Compared with other tumor types, liver metastases of colorectal cancer contain large amounts of hypoxic cells. The lack of correlation with pimonidazole binding brings into question the value of GLUT1 and CA-IX as endogenous markers of hypoxia.", "title": "Hypoxia in relation to vasculature and proliferation in liver metastases in patients with colorectal cancer." }, { "docid": "15648443", "text": "BACKGROUND Observational studies report reduced colorectal cancer in regular aspirin consumers. Randomised controlled trials have shown reduced risk of adenomas but none have employed prevention of colorectal cancer as a primary endpoint. The CAPP2 trial aimed to investigate the antineoplastic effects of aspirin and a resistant starch in carriers of Lynch syndrome, the major form of hereditary colorectal cancer; we now report long-term follow-up of participants randomly assigned to aspirin or placebo. \n METHODS In the CAPP2 randomised trial, carriers of Lynch syndrome were randomly assigned in a two-by-two factorial design to 600 mg aspirin or aspirin placebo or 30 g resistant starch or starch placebo, for up to 4 years. Randomisation was in blocks of 16 with provision for optional single-agent randomisation and extended postintervention double-blind follow-up; participants and investigators were masked to treatment allocation. The primary endpoint was development of colorectal cancer. Analysis was by intention to treat and per protocol. This trial is registered, ISRCTN59521990. \n RESULTS 861 participants were randomly assigned to aspirin or aspirin placebo. At a mean follow-up of 55·7 months, 48 participants had developed 53 primary colorectal cancers (18 of 427 randomly assigned to aspirin, 30 of 434 to aspirin placebo). Intention-to-treat analysis of time to first colorectal cancer showed a hazard ratio (HR) of 0·63 (95% CI 0·35-1·13, p=0·12). Poisson regression taking account of multiple primary events gave an incidence rate ratio (IRR) of 0·56 (95% CI 0·32-0·99, p=0·05). For participants completing 2 years of intervention (258 aspirin, 250 aspirin placebo), per-protocol analysis yielded an HR of 0·41 (0·19-0·86, p=0·02) and an IRR of 0·37 (0·18-0·78, p=0·008). No data for adverse events were available postintervention; during the intervention, adverse events did not differ between aspirin and placebo groups. \n INTERPRETATION 600 mg aspirin per day for a mean of 25 months substantially reduced cancer incidence after 55·7 months in carriers of hereditary colorectal cancer. Further studies are needed to establish the optimum dose and duration of aspirin treatment. \n FUNDING European Union; Cancer Research UK; Bayer Corporation; National Starch and Chemical Co; UK Medical Research Council; Newcastle Hospitals trustees; Cancer Council of Victoria Australia; THRIPP South Africa; The Finnish Cancer Foundation; SIAK Switzerland; Bayer Pharma.", "title": "Long-term effect of aspirin on cancer risk in carriers of hereditary colorectal cancer: an analysis from the CAPP2 randomised controlled trial" }, { "docid": "10463997", "text": "Objectives: Autophagy is a highly regulated process that has an important role in the control of a wide range of cellular functions, such as organelle recycling, nutrient availability and tissue differentiation. A recent study has shown an increased autophagic activity in the adipose tissue of obese subjects, and a role for autophagy in obesity-associated insulin resistance was proposed. Body mass reduction is the most efficient approach to tackle insulin resistance in over-weight subjects; however, the impact of weight loss in adipose tissue autophagy is unknown. Subjects:Adipose tissue autophagy was evaluated in mice and humans. Results:First, a mouse model of diet-induced obesity and diabetes was maintained on a 15-day, 40% caloric restriction. At baseline, markers of autophagy were increased in obese mice as compared with lean controls. Upon caloric restriction, autophagy increased in the lean mice, whereas it decreased in the obese mice. The reintroduction of ad libitum feeding was sufficient to rapidly reduce autophagy in the lean mice and increase autophagy in the obese mice. In the second part of the study, autophagy was evaluated in the subcutaneous adipose tissue of nine obese-non-diabetic and six obese-diabetic subjects undergoing bariatric surgery for body mass reduction. Specimens were collected during the surgery and approximately 1 year later. Markers of systemic inflammation, such as tumor necrosis factor-1α, interleukin (IL)-6 and IL-1β were evaluated. As in the mouse model, human obesity was associated with increased autophagy, and body mass reduction led to an attenuation of autophagy in the adipose tissue. Conclusion:Obesity and caloric overfeeding are associated with the defective regulation of autophagy in the adipose tissue. The studies in obese-diabetic subjects undergoing improved metabolic control following calorie restriction suggest that autophagy and inflammation are regulated independently.", "title": "Defective regulation of adipose tissue autophagy in obesity" }, { "docid": "23830488", "text": "Circadian rhythms are daily oscillations in various biological processes, generated by the feedback loops of eight core circadian genes: Period1 (Per1), Period2 (Per2), Period3 (Per3), Cryptochrome1 (Cry1), Cryptochrome2 (Cry2), Clock, Bmal1 and Casein Kinase I ε (CKIε). Recent studies have suggested that circadian genes participate in the growth and development of various cancers. This study examined the relations of circadian gene expression to clinicopathological factors and outcomes in patients with colorectal cancer. We studied surgical specimens of cancer tissue and adjacent normal mucosa obtained from 202 patients with untreated colorectal cancer. The relative expression levels of the circadian genes in the specimens were measured by quantitative real-time, reverse-transcription polymerase chain reaction. Expression of the Clock gene and the CKIε gene in cancer tissue were significantly higher compared to that in adjacent normal mucosa. Expression of the Per1 and Per3 genes in cancer tissue was significantly lower compared to that in adjacent normal mucosa. Analysis of the relations between clinicopathological features and expression of the eight circadian genes in cancer tissue showed that high expression of the Bmal1 gene and low expression of the Per1 gene correlated with liver metastasis. On analysis of the relations between outcomes and gene expression, high expression of the Per2 gene was associated with significantly better outcomes than low expression of the Per2 gene. Overexpression of the Bmal1 gene and reduced expression of the Per1 gene may thus be useful predictors of liver metastasis. Moreover, reduced expression of the Per2 gene may be a predictor of outcomes in patients with colorectal cancer.", "title": "Expression of circadian genes correlates with liver metastasis and outcomes in colorectal cancer." }, { "docid": "3590806", "text": "BACKGROUND Colorectal cancer remains one of the most common malignant tumors worldwide. Colorectal cancer initiating cells (CCICs) are a small subpopulation responsible for malignant behaviors of colorectal cancer. Aberrant activation of the Wnt pathways regulates the self-renewal of CCIC. However, the underlying mechanism(s) remain poorly understood. \n METHODS Via retroviral library screening, we identified Nuclear Receptor-Interacting Protein 2 (NRIP2) as a novel interactor of the Wnt pathway from enriched colorectal cancer colosphere cells. The expression levels of NRIP2 and retinoic acid-related orphan receptor β (RORβ) were further examined by FISH, qRT-PCR, IHC and Western blot. NRIP2 overexpressed and knockdown colorectal cancer cells were produced to study the role of NRIP2 in Wnt pathway. We also verified the binding between NRIP2 and RORβ and investigated the effect of RORβ on CCICs both in vitro and in vivo. Genechip-scanning speculated downstream target HBP1. Western blot, ChIP and luciferase reporter were carried to investigate the interaction between NRIP2, RORβ, and HBP1. \n RESULTS NRIP2 was significantly up-regulated in CCICs from both cell lines and primary colorectal cancer tissues. Reinforced expression of NRIP2 increased Wnt activity, while silencing of NRIP2 attenuated Wnt activity. The transcription factor RORβ was a key target through which NRIP2 regulated Wnt pathway activity. RORβ was a transcriptional enhancer of inhibitor HBP1 of the Wnt pathway. NRIP2 prevented RORβ to bind with downstream HBP1 promoter regions and reduced the transcription of HBP1. This, in turn, attenuated the HBP1-dependent inhibition of TCF4-mediated transcription. \n CONCLUSIONS NRIP2 is a novel interactor of the Wnt pathway in colorectal cancer initiating cells. interactions between NRIP2, RORβ, and HBP1 mediate a new mechanism for CCIC self-renewal via the Wnt activity.", "title": "Up-regulated NRIP2 in colorectal cancer initiating cells modulates the Wnt pathway by targeting RORβ" }, { "docid": "42731834", "text": "Functional studies on colorectal cancer cells indicated a protective role of the interferon-inducible dsDNA sensor Absent in Melanoma 2 (AIM2) in cancer progression. Given that a high mutation rate and lack of AIM2 expression was previously detected in a subset of colorectal cancers, we here investigated the association of AIM2 expression in tumor cells and patient prognosis (5-year follow-up). A tissue microarray analysis of 476 matched tissue pairs (colorectal tumor and adjacent normal colon epithelium) was performed by two independent observers. Samples from 62 patients were excluded because of missing follow-up information or due to neo-adjuvant therapy before tissue sampling. Out of the remaining 414 tissue pairs, 279 (67.4%) displayed reduced AIM2 expression in cancer cells when compared to epithelial cells of their normal counterpart. Thirty-eight patients (9.18%) had completely lost AIM2 expression in tumor cells. After adjustment for sex, age, cancer stage, tumor site, tumor grade and chemotherapy, complete lack of AIM2 expression was associated with an up to 3-fold increase in overall mortality (HR=2.40; 95% CI=1.44-3.99) and disease specific mortality (HR=3.14; 95% CI=1.75-5.65) in comparison to AIM2-positive tumor samples. Our results demonstrate that lack of AIM2 expression is closely associated with poor outcome in colorectal cancer. The data thus strongly substantiate a protective role of AIM2 against progression of colorectal tumors. Further studies are required to assess whether lack of AIM2 expression may be used as a biomarker for the identification of colorectal cancer patients with poor prognosis.", "title": "Lack of Absent in Melanoma 2 (AIM2) expression in tumor cells is closely associated with poor survival in colorectal cancer patients." }, { "docid": "79447", "text": "OBJECTIVE The purpose of this study was to characterize the relationship between adipose tissue phenotype and depot-specific microvascular function in fat. \n METHODS AND RESULTS In 30 obese subjects (age 42±11 years, body mass index 46±11 kg/m(2)) undergoing bariatric surgery, we intraoperatively collected visceral and subcutaneous adipose tissue and characterized depot-specific adipose phenotypes. We assessed vasomotor function of the adipose microvasculature using videomicroscopy of small arterioles (75-250 μm) isolated from different fat compartments. Endothelium-dependent, acetylcholine-mediated vasodilation was severely impaired in visceral arterioles, compared to the subcutaneous depot (P<0.001 by ANOVA). Nonendothelium dependent responses to papaverine and nitroprusside were similar. Endothelial nitric oxide synthase inhibition with N(ω)-nitro-l-arginine methyl ester reduced subcutaneous vasodilation but had no effect on severely blunted visceral arteriolar responses. Visceral fat exhibited greater expression of proinflammatory, oxidative stress-related, hypoxia-induced, and proangiogenic genes; increased activated macrophage populations; and had a higher capacity for cytokine production ex vivo. \n CONCLUSIONS Our findings provide clinical evidence that the visceral microenvironment may be intrinsically toxic to arterial health providing a potential mechanism by which visceral adiposity burden is linked to atherosclerotic vascular disease. Our findings also support the evolving concept that both adipose tissue quality and quantity may play significant roles in shaping cardiovascular phenotypes in human obesity.", "title": "Arteriolar function in visceral adipose tissue is impaired in human obesity." }, { "docid": "7613033", "text": "Considerable evidence supports the effectiveness of aspirin for chemoprevention of colorectal cancer (CRC) in addition to its well-established benefits in the prevention of vascular disease. Epidemiologic studies have consistently observed an inverse association between aspirin use and risk of CRC. A recent pooled analysis of a long-term posttrial follow-up of nearly 14,000 patients from four randomized, cardiovascular disease prevention trials showed that daily aspirin treatment for about five years was associated with a 34% reduction in 20-year CRC mortality. A separate metaanalysis of nearly 3,000 patients with a history of colorectal adenoma or cancer in four randomized adenoma prevention trials showed that aspirin reduced the occurrence of advanced adenomas by 28% and any adenoma by 17%. Aspirin has also been shown to be beneficial in a clinical trial of patients with Lynch syndrome, a hereditary CRC syndrome; in those treated with aspirin for at least two years, there was a 50% or more reduction in the risk of CRC commencing five years after randomization and after aspirin had been discontinued. A few observational studies have shown an increase in survival among patients with CRC who use aspirin. Taken together, these findings strengthen the case for consideration of long-term aspirin use in CRC prevention. Despite these compelling data, there is a lack of consensus about the balance of risks and benefits associated with long-term aspirin use, particularly in low-risk populations. The optimal dose to use for cancer prevention and the precise mechanism underlying aspirin's anticancer effect require further investigation.", "title": "Aspirin in the chemoprevention of colorectal neoplasia: an overview." }, { "docid": "7165938", "text": "PURPOSE The circadian clock gene Bmal1 is involved in cancer cell proliferation and DNA damage sensitivity. The aim of this study was to explore the effect of Bmal1 on oxaliplatin sensitivity and to determine its clinical significance in colorectal cancer. EXPERIMENTAL DESIGN Three colorectal cancer cell lines, HCT116, THC8307 and HT29, were used. The Bmal1-mediated control of colorectal cancer cell proliferation was tested in vitro and in vivo. MTT and colony formation assays were performed to determine the sensitivity of colorectal cancer cells to oxaliplatin. Flow cytometry was used to examine changes in the cell-cycle distribution and apoptosis rate. Proteins expressed downstream of Bmal1 upon its overexpression were determined by Western blotting. Immunohistochemistry was used to analyze Bmal1 expression in 82 archived colorectal cancer tumors from patients treated with oxaliplatin-based regimens. \n RESULTS Bmal1 overexpression inhibited colorectal cancer cell proliferation and increased colorectal cancer sensitivity to oxaliplatin in three colorectal cancer cell lines and HCT116 cells model in vivo. Furthermore, the overall survival of patients with colorectal cancer with high Bmal1 levels in their primary tumors was significantly longer than that of patients with low Bmal1 levels (27 vs. 19 months; P = 0.043). The progression-free survival of patients with high Bmal1 expression was also significantly longer than that of patients with low Bmal1 expression (11 vs. 5 months; P = 0.015). Mechanistically, the effect of Bmal1 was associated with its ability to regulate G2-M arrest by activating the ATM pathway. \n CONCLUSION Bmal1 shows the potential as a novel prognostic biomarker and may represent a new therapeutic target in colorectal cancer.", "title": "Overexpression of the circadian clock gene Bmal1 increases sensitivity to oxaliplatin in colorectal cancer." }, { "docid": "9558539", "text": "Cancer stem cells drive tumor formation and metastasis, but how they acquire metastatic traits is not well understood. Here, we show that all colorectal cancer stem cells (CR-CSCs) express CD44v6, which is required for their migration and generation of metastatic tumors. CD44v6 expression is low in primary tumors but demarcated clonogenic CR-CSC populations. Cytokines hepatocyte growth factor (HGF), osteopontin (OPN), and stromal-derived factor 1α (SDF-1), secreted from tumor associated cells, increase CD44v6 expression in CR-CSCs by activating the Wnt/β-catenin pathway, which promotes migration and metastasis. CD44v6(-) progenitor cells do not give rise to metastatic lesions but, when treated with cytokines, acquire CD44v6 expression and metastatic capacity. Importantly, phosphatidylinositol 3-kinase (PI3K) inhibition selectively killed CD44v6 CR-CSCs and reduced metastatic growth. In patient cohorts, low levels of CD44v6 predict increased probability of survival. Thus, the metastatic process in colorectal cancer is initiated by CSCs through the expression of CD44v6, which is both a functional biomarker and therapeutic target.", "title": "CD44v6 is a marker of constitutive and reprogrammed cancer stem cells driving colon cancer metastasis." }, { "docid": "15476777", "text": "BACKGROUND Elderly and frail patients with cancer, although often treated with chemotherapy, are under-represented in clinical trials. We designed FOCUS2 to investigate reduced-dose chemotherapy options and to seek objective predictors of outcome in frail patients with advanced colorectal cancer. \n METHODS We undertook an open, 2 × 2 factorial trial in 61 UK centres for patients with previously untreated advanced colorectal cancer who were considered unfit for full-dose chemotherapy. After comprehensive health assessment (CHA), patients were randomly assigned by minimisation to: 48-h intravenous fluorouracil with levofolinate (group A); oxaliplatin and fluorouracil (group B); capecitabine (group C); or oxaliplatin and capecitabine (group D). Treatment allocation was not masked. Starting doses were 80% of standard doses, with discretionary escalation to full dose after 6 weeks. The two primary outcome measures were: addition of oxaliplatin ([A vs B] + [C vs D]), assessed with progression-free survival (PFS); and substitution of fluorouracil with capecitabine ([A vs C] + [B vs D]), assessed by change from baseline to 12 weeks in global quality of life (QoL). Analysis was by intention to treat. Baseline clinical and CHA data were modelled against outcomes with a novel composite measure, overall treatment utility (OTU). This study is registered, number ISRCTN21221452. \n FINDINGS 459 patients were randomly assigned (115 to each of groups A-C, 114 to group D). Factorial comparison of addition of oxaliplatin versus no addition suggested some improvement in PFS, but the finding was not significant (median 5·8 months [IQR 3·3-7·5] vs 4·5 months [2·8-6·4]; hazard ratio 0·84, 95% CI 0·69-1·01, p=0·07). Replacement of fluorouracil with capecitabine did not improve global QoL: 69 of 124 (56%) patients receiving fluorouracil reported improvement in global QoL compared with 69 of 123 (56%) receiving capecitabine. The risk of having any grade 3 or worse toxic effect was not significantly increased with oxaliplatin (83/219 [38%] vs 70/221 [32%]; p=0·17), but was higher with capecitabine than with fluorouracil (88/222 [40%] vs 65/218 [30%]; p=0·03). In multivariable analysis, fewer baseline symptoms (odds ratio 1·32, 95% CI 1·14-1·52), less widespread disease (1·51, 1·05-2·19), and use of oxaliplatin (0·57, 0·39-0·82) were predictive of better OTU. \n INTERPRETATION FOCUS2 shows that with an appropriate design, including reduced starting doses of chemotherapy, frail and elderly patients can participate in a randomised controlled trial. On balance, a combination including oxaliplatin was preferable to single-agent fluoropyrimidines, although the primary endpoint of PFS was not met. Capecitabine did not improve QoL compared with fluorouracil. Comprehensive baseline assessment holds promise as an objective predictor of treatment benefit. \n FUNDING Cancer Research UK and the Medical Research Council.", "title": "Chemotherapy options in elderly and frail patients with metastatic colorectal cancer (MRC FOCUS2): an open-label, randomised factorial trial" }, { "docid": "43334921", "text": "IMPORTANCE Use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with lower risk of colorectal cancer. \n OBJECTIVE To identify common genetic markers that may confer differential benefit from aspirin or NSAID chemoprevention, we tested gene × environment interactions between regular use of aspirin and/or NSAIDs and single-nucleotide polymorphisms (SNPs) in relation to risk of colorectal cancer. \n DESIGN, SETTING, AND PARTICIPANTS Case-control study using data from 5 case-control and 5 cohort studies initiated between 1976 and 2003 across the United States, Canada, Australia, and Germany and including colorectal cancer cases (n=8634) and matched controls (n=8553) ascertained between 1976 and 2011. Participants were all of European descent. EXPOSURES Genome-wide SNP data and information on regular use of aspirin and/or NSAIDs and other risk factors. \n MAIN OUTCOMES AND MEASURES Colorectal cancer. \n RESULTS Regular use of aspirin and/or NSAIDs was associated with lower risk of colorectal cancer (prevalence, 28% vs 38%; odds ratio [OR], 0.69 [95% CI, 0.64-0.74]; P = 6.2 × 10(-28)) compared with nonregular use. In the conventional logistic regression analysis, the SNP rs2965667 at chromosome 12p12.3 near the MGST1 gene showed a genome-wide significant interaction with aspirin and/or NSAID use (P = 4.6 × 10(-9) for interaction). Aspirin and/or NSAID use was associated with a lower risk of colorectal cancer among individuals with rs2965667-TT genotype (prevalence, 28% vs 38%; OR, 0.66 [95% CI, 0.61-0.70]; P = 7.7 × 10(-33)) but with a higher risk among those with rare (4%) TA or AA genotypes (prevalence, 35% vs 29%; OR, 1.89 [95% CI, 1.27-2.81]; P = .002). In case-only interaction analysis, the SNP rs16973225 at chromosome 15q25.2 near the IL16 gene showed a genome-wide significant interaction with use of aspirin and/or NSAIDs (P = 8.2 × 10(-9) for interaction). Regular use was associated with a lower risk of colorectal cancer among individuals with rs16973225-AA genotype (prevalence, 28% vs 38%; OR, 0.66 [95% CI, 0.62-0.71]; P = 1.9 × 10(-30)) but was not associated with risk of colorectal cancer among those with less common (9%) AC or CC genotypes (prevalence, 36% vs 39%; OR, 0.97 [95% CI, 0.78-1.20]; P = .76). \n CONCLUSIONS AND RELEVANCE In this genome-wide investigation of gene × environment interactions, use of aspirin and/or NSAIDs was associated with lower risk of colorectal cancer, and this association differed according to genetic variation at 2 SNPs at chromosomes 12 and 15. Validation of these findings in additional populations may facilitate targeted colorectal cancer prevention strategies.", "title": "Association of aspirin and NSAID use with risk of colorectal cancer according to genetic variants." } ]

[ { "docid": "5824985", "text": "BACKGROUND Bariatric surgery is becoming a more widespread treatment for obesity. Comprehensive evidence of the long-term effects of contemporary surgery on a broad range of clinical outcomes in large populations treated in routine clinical practice is lacking. The objective of this study was to measure the association between bariatric surgery, weight, body mass index, and obesity-related co-morbidities. \n METHODS AND FINDINGS This was an observational retrospective cohort study using data from the United Kingdom Clinical Practice Research Datalink. All 3,882 patients registered in the database and with bariatric surgery on or before 31 December 2014 were included and matched by propensity score to 3,882 obese patients without surgery. The main outcome measures were change in weight and body mass index over 4 y; incident diagnoses of type 2 diabetes mellitus (T2DM), hypertension, angina, myocardial infarction (MI), stroke, fractures, obstructive sleep apnoea, and cancer; mortality; and resolution of hypertension and T2DM. Weight measures were available for 3,847 patients between 1 and 4 mo, 2,884 patients between 5 and 12 mo, and 2,258 patients between 13 and 48 mo post-procedure. Bariatric surgery patients exhibited rapid weight loss for the first four postoperative months, at a rate of 4.98 kg/mo (95% CI 4.88-5.08). Slower weight loss was sustained to the end of 4 y. Gastric bypass (6.56 kg/mo) and sleeve gastrectomy (6.29 kg/mo) were associated with greater initial weight reduction than gastric banding (2.77 kg/mo). Protective hazard ratios (HRs) were detected for bariatric surgery for incident T2DM, 0.68 (95% CI 0.55-0.83); hypertension, 0.35 (95% CI 0.27-0.45); angina, 0.59 (95% CI 0.40-0.87);MI, 0.28 (95% CI 0.10-0.74); and obstructive sleep apnoea, 0.55 (95% CI 0.40-0.87). Strong associations were found between bariatric surgery and the resolution of T2DM, with a HR of 9.29 (95% CI 6.84-12.62), and between bariatric surgery and the resolution of hypertension, with a HR of 5.64 (95% CI 2.65-11.99). No association was detected between bariatric surgery and fractures, cancer, or stroke. Effect estimates for mortality found no protective association with bariatric surgery overall, with a HR of 0.97 (95% CI 0.66-1.43). The data used were recorded for the management of patients in primary care and may be subject to inaccuracy, which would tend to lead to underestimates of true relative effect sizes. \n CONCLUSIONS Bariatric surgery as delivered in the UK healthcare system is associated with dramatic weight loss, sustained at least 4 y after surgery. This weight loss is accompanied by substantial improvements in pre-existing T2DM and hypertension, as well as a reduced risk of incident T2DM, hypertension, angina, MI, and obstructive sleep apnoea. Widening the availability of bariatric surgery could lead to substantial health benefits for many people who are morbidly obese.", "title": "Bariatric Surgery in the United Kingdom: A Cohort Study of Weight Loss and Clinical Outcomes in Routine Clinical Care." } ]

[ { "docid": "7627167", "text": "BACKGROUND The objective of this study was to evaluate the effectiveness of a brief, 4-session cognitive behavioral, group psychotherapy for binge eating among bariatric surgery candidates at an academic medical center. Binge eating behaviors have been linked to poorer outcomes among bariatric surgery patients, and binge eating disorder have be considered a contraindication in surgery programs, some of which have mandated preoperative binge eating treatment. However, no previous studies have examined whether a preoperative binge eating intervention could successfully reduce binge eating behaviors among severely obese bariatric surgery candidates. \n METHODS A total of 243 bariatric surgery candidates completed a brief cognitive behavioral group treatment for binge eating behaviors and were administered the Binge Eating Scale and reported the number of weekly binge eating episodes at the initial psychological evaluation and again after the group sessions. The study used a pre-post intervention design. \n RESULTS The results suggested significant reductions in both binge eating behaviors and cognitions and binge eating episodes after the group intervention. The intervention's effectiveness did not differ according to gender or ethnicity (black versus white). \n CONCLUSION A brief cognitive behavioral intervention can reduce binge eating behaviors among bariatric surgery candidates. Given the potential influence of binge eating on outcomes, bariatric surgery programs could benefit by treating binge eating before surgery.", "title": "Brief, four-session group CBT reduces binge eating behaviors among bariatric surgery candidates." }, { "docid": "15559582", "text": "In a comparative study of pre- and postmenopausal women with benign and malignant breast disease, a number of differences were observed in circulating plasma prolactin and lipid concentrations. Plasma lipids, phospholipids, triglycerides, cholesterol and free fatty acids were all higher in blood obtained from breast cancer patients prior to surgery. HDL-Cholesterol levels were significantly lower in these patients. These differences remained when the patient groups were sub-divided according to menopausal status. Plasma prolactin concentrations were also found to be higher in cancer compared with non-cancer patients, this effect being more marked in premenopausal than in postmenopausal patients. Premenopausal patients with invasive or poorly differentiated disease had significantly higher prolactin levels than those with non-invasive disease. No correlations were found between plasma prolactin and any of the lipid fractions.", "title": "Plasma lipids and prolactin in patients with breast cancer." }, { "docid": "13831842", "text": "The association between anthropometric indices and the risk of breast cancer was analyzed using pooled data from seven prospective cohort studies. Together, these cohorts comprise 337,819 women and 4,385 incident invasive breast cancer cases. In multivariate analyses controlling for reproductive, dietary, and other risk factors, the pooled relative risk (RR) of breast cancer per height increment of 5 cm was 1.02 (95% confidence interval (CI): 0.96, 1.10) in premenopausal women and 1.07 (95% CI: 1.03, 1.12) in postmenopausal women. Body mass index (BMI) showed significant inverse and positive associations with breast cancer among pre- and postmenopausal women, respectively; these associations were nonlinear. Compared with premenopausal women with a BMI of less than 21 kg/m2, women with a BMI exceeding 31 kg/m2 had an RR of 0.54 (95% CI: 0.34, 0.85). In postmenopausal women, the RRs did not increase further when BMI exceeded 28 kg/m2; the RR for these women was 1.26 (95% CI: 1.09, 1.46). The authors found little evidence for interaction with other breast cancer risk factors. Their data indicate that height is an independent risk factor for postmenopausal breast cancer; in premenopausal women, this relation is less clear. The association between BMI and breast cancer varies by menopausal status. Weight control may reduce the risk among postmenopausal women.", "title": "Pooled analysis of prospective cohort studies on height, weight, and breast cancer risk." }, { "docid": "38551172", "text": "Mammographic density is a strong risk factor for breast cancer, but the underlying biology for this association is unknown. Studies suggest that vitamin D may reduce breast cancer risk and dietary vitamin D intake has been associated with reduced breast density. We conducted a case-control study nested within the Nurses' Health Study cohort consisting of 463 and 497 postmenopausal cases and controls, respectively. We examined the association between mammographic density and plasma levels of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)(2)D]. We assessed whether plasma vitamin D metabolites modify the association between breast density and breast cancer. Percent mammographic density was measured from digitized film mammograms. Generalized linear models were used to determine mean percent breast density per quartile of vitamin D metabolite. Logistic regression models were used to calculate relative risks and confidence intervals. All models were adjusted for matching variables and potential confounders. We found no cross-sectional association between circulating levels of 25(OH)D or 1,25(OH)(2)D with mammographic density. Women in the highest tertile of mammographic density and lowest tertile of plasma 25(OH)D had 4 times greater risk of breast cancer than women with the lowest mammographic density and highest plasma 25(OH)D levels (RR = 3.8; 95% CI: 2.0-7.3). The overall interaction between mammographic density and plasma 25(OH)D was nonsignificant (p-het = 0.20). These results indicate that the association between mammographic density and breast cancer is independent of plasma vitamin D metabolites in postmenopausal women. Further research examining vitamin D, mammographic density and breast cancer risk is warranted.", "title": "Mammographic density, plasma vitamin D levels and risk of breast cancer in postmenopausal women." }, { "docid": "18872233", "text": "IMPORTANCE Bariatric surgery is associated with sustained weight loss and improved physical health status for severely obese individuals. Mental health conditions may be common among patients seeking bariatric surgery; however, the prevalence of these conditions and whether they are associated with postoperative outcomes remains unknown. \n OBJECTIVE To determine the prevalence of mental health conditions among bariatric surgery candidates and recipients, to evaluate the association between preoperative mental health conditions and health outcomes following bariatric surgery, and to evaluate the association between surgery and the clinical course of mental health conditions. \n DATA SOURCES We searched PubMed, MEDLINE on OVID, and PsycINFO for studies published between January 1988 and November 2015. Study quality was assessed using an adapted tool for risk of bias; quality of evidence was rated based on GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. \n FINDINGS We identified 68 publications meeting inclusion criteria: 59 reporting the prevalence of preoperative mental health conditions (65,363 patients) and 27 reporting associations between preoperative mental health conditions and postoperative outcomes (50,182 patients). Among patients seeking and undergoing bariatric surgery, the most common mental health conditions, based on random-effects estimates of prevalence, were depression (19% [95% CI, 14%-25%]) and binge eating disorder (17% [95% CI, 13%-21%]). There was conflicting evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Neither depression nor binge eating disorder was consistently associated with differences in weight outcomes. Bariatric surgery was, however, consistently associated with postoperative decreases in the prevalence of depression (7 studies; 8%-74% decrease) and the severity of depressive symptoms (6 studies; 40%-70% decrease). \n CONCLUSIONS AND RELEVANCE Mental health conditions are common among bariatric surgery patients-in particular, depression and binge eating disorder. There is inconsistent evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Moderate-quality evidence supports an association between bariatric surgery and lower rates of depression postoperatively.", "title": "Mental Health Conditions Among Patients Seeking and Undergoing Bariatric Surgery: A Meta-analysis." }, { "docid": "29022271", "text": "Psychosocial factors have significant potential to affect long-term outcomes of bariatric surgery, including emotional adjustment, adherence to the recommended postoperative lifestyle regimen, weight loss outcomes, and co-morbidity improvement and or resolution. Thus, it is recommended that bariatric behavioral health clinicians with specialized knowledge and experience be involved in the evaluation and care of patients both before and after surgery. The evaluating clinician plays a number of important roles in the multidisciplinary treatment of the bariatric patient. Central among these is the role of identifying factors that may pose challenges to optimal surgical outcome and providing recommendations to the patient and bariatric team on how to address these issues. This document outlines recommendations for the psychosocial evaluation of bariatric surgery patients, appropriate qualifications of those conducting these evaluations, communication of evaluation results and suggested treatment plan, and the extension of behavioral healthcare of the bariatric patient to the entire span of the surgical and postsurgical process.", "title": "Recommendations for the presurgical psychosocial evaluation of bariatric surgery patients." }, { "docid": "43220289", "text": "Extreme obesity is associated with severe psychiatric and somatic comorbidity and impairment of psychosocial functioning. Bariatric surgery is the most effective treatment not only with regard to weight loss but also with obesity-associated illnesses. Health-related psychological and psychosocial variables have been increasingly considered as important outcome variables of bariatric surgery. However, the long-term impact of bariatric surgery on psychological and psychosocial functioning is largely unclear. The aim of this study was to evaluate the relationship between the course of weight and psychological variables including depression, anxiety, health-related quality of life (HRQOL), and self-esteem up to 4 years after obesity surgery. By standardized questionnaires prior to (T1) and 1 year (T2), 2 years (T3), and 4 years (T4) after surgery, 148 patients (47 males (31.8 %), 101 females (68.2 %), mean age 38.8 ± 10.2 years) were assessed. On average, participants lost 24.6 % of their initial weight 1 year after surgery, 25.1 % after 2 years, and 22.3 % after 4 years. Statistical analysis revealed significant improvements in depressive symptoms, physical dimension of quality of life, and self-esteem with peak improvements 1 year after surgery. These improvements were largely maintained. Significant correlations between weight loss and improvements in depression, physical aspects of HRQOL (T2, T3, and T4), and self-esteem (T3) were observed. Corresponding to the considerable weight loss after bariatric surgery, important aspects of mental health improved significantly during the 4-year follow-up period. However, parallel to weight regain, psychological improvements showed a slow but not significant decline over time.", "title": "Psychological Outcome 4 Years after Restrictive Bariatric Surgery" }, { "docid": "5864770", "text": "Epidemiologic studies suggest that ovarian hormones contribute to the development of breast cancer at all stages. Early menopause and premenopausal obesity reduces the risk while postmenopausal obesity and menopausal estrogen replacement therapy increases the risk. Combined oral contraceptives and Depo-Provera do not reduce the risk. It appears that estrogens and progestogens act through and with proto-oncogenes and growth factors to affect breast cell proliferation and breast cancer etiology. Animal studies suggest that estrogen causes interlobular ductal cell division and progesterone causes increased terminal duct lobular unit cell division in the luteal phase. Most breast carcinomas originate from terminal duct lobular unit cells. During pregnancy, these cells fully multiply. Their reproduction is also increased during the luteal phase. Yet, there is considerable interpersonal variation. No studies examining breast cell division have compared cell division rates with serum hormone concentrations, however. The peak of mitosis occurs about 3 days before breast cell death in the late luteal and very early follicular phases. Other research suggests that breast stem cell proliferation is linked to breast cancer development. Endocrine therapy reduces mitotic activity, indicating the estrogen and progesterone receptor content of breast cancers. Hormone-dependent breast cancer cell lines are all estrogen-dependent. Progesterone can block the estrogen-dependent cell lines which act like endometrial cells. The results of the various breast cell proliferation studies in relation to breast cancer are unclear and research identifying a molecular explanation would help in understanding the different findings.", "title": "Estrogens, progestogens, normal breast cell proliferation, and breast cancer risk." }, { "docid": "25973484", "text": "Obesity has a complicated relationship to both breast cancer risk and the clinical behavior of the established disease. In postmenopausal women, particularly the elderly, various measures of obesity have been positively associated with risk. However, before menopause increased body weight is inversely related to breast cancer risk. In both premenopausal and postmenopausal breast cancer, the mechanisms by which body weight and obesity affect risk have been related to estrogenic activity. Obesity has also been related to advanced disease at diagnosis and with a poor prognosis in both premenopausal and postmenopausal breast cancer. Breast cancer in African-American women, considering its relationship to obesity, exhibits some important differences from those described in white women, although the high prevalence of obesity in African-American women may contribute to the relatively poor prognosis compared with white American women. Despite the emphasis on estrogens to explain the effects of obesity on breast cancer, other factors may prove to be equally or more important, particularly as they relate to expression of an aggressive tumor phenotype. Among these, this review serves to stress insulin, insulin-like growth factor-I, and leptin, and their relationship to angiogenesis, and transcriptional factors.", "title": "Breast cancer and obesity: an update." }, { "docid": "40949706", "text": "Obesity affects 32% of adults in the USA. Surgery generates substantial weight loss, but 20–30% fails to achieve successful weight loss. Our objective was to identify preoperative psychosocial factors associated with weight loss following bariatric surgery. We performed a literature search of PubMed® and the Cochrane Database of Reviews of Effectiveness between 1988 and April 2010. Articles were screened for bariatric surgery and weight loss if they included a preoperative predictor of weight loss: body mass index (BMI), preoperative weight loss, eating disorders, or psychiatric disorder/substance abuse. One thousand seven titles were reviewed, 534 articles screened, and 115 included in the review. Factors that may be positively associated with weight loss after surgery include mandatory preoperative weight loss (7 of 14 studies with positive association). Factors that may be negatively associated with weight loss include preoperative BMI (37 out of 62 studies with negative association), super-obesity (24 out of 33 studies), and personality disorders (7 out of 14 studies). Meta-analysis revealed a decrease of 10.1% excess weight loss (EWL) for super-obese patients (95% confidence interval (CI) [3.7–16.5%]), though there was significant heterogeneity in the meta-analysis, and an increase of 5.9% EWL for patients with binge eating at 12 months after surgery (95% CI [1.9–9.8%]). Further studies are necessary to investigate whether preoperative factors can predict a clinically meaningful difference in weight loss after bariatric surgery. The identification of predictive factors may improve patient selection and help develop interventions targeting specific needs of patients.", "title": "Preoperative Predictors of Weight Loss Following Bariatric Surgery: Systematic Review" }, { "docid": "16701509", "text": "BACKGROUND The prevalence of metabolic syndrome (obesity, glucose intolerance, low serum high-density lipoprotein cholesterol [HDL-C], high serum triglycerides, hypertension) is high and increasing in parallel with an increasing breast cancer incidence worldwide. HDL-C represents an important aspect of the syndrome, yet its role in breast cancer is still undefined. \n METHODS In two population-based screening surveys during 1977-1983 and 1985-1987, serum HDL-C was assayed enzymatically among 38,823 Norwegian women aged 17-54 years at entry. Height, weight, blood pressure, serum lipids, fat and energy intake, physical activity, parity, oral contraceptive use, hormone therapy use, alcohol intake, and tobacco use were also assessed. We used Cox proportional hazards modeling to estimate the relative risk (RR) of breast cancer associated with serum HDL-C levels and to adjust for potential confounding variables. We performed stratified analyses to evaluate effect modification by body mass index (BMI) and menopausal status. All statistical tests were two-sided. \n RESULTS During a median follow-up of 17.2 years, we identified 708 cases of invasive breast cancer. In multivariable analysis, the risk of postmenopausal breast cancer was inversely related to quartile of HDL-C (P(trend) =.02). Among women with HDL-C above 1.64 mmol/L (highest quartile) versus below 1.20 mmol/L (lowest quartile), the relative risk was 0.75 (95% confidence interval [CI] = 0.58 to 0.97). The HDL-C association was confined to women in the heavier subgroup (BMI > or =25 kg/m2), for whom the relative risk of postmenopausal breast cancer in those with HDL-C above 1.64 mmol/L versus below 1.20 mmol/L was 0.43 (95% CI = 0.28 to 0.67; P(trend)<.001; P(interaction) =.001). \n CONCLUSION Low HDL-C, as part of the metabolic syndrome, is associated with increased postmenopausal breast cancer risk.", "title": "Serum high-density lipoprotein cholesterol, metabolic profile, and breast cancer risk." }, { "docid": "19071857", "text": "Pre-operative psychological assessment is recommended by international guidelines for bariatric surgery candidates. Thereby, service teams caring for bariatric patients should include at least one mental health provider (e.g., a psychologist or psychiatrist). The objective of this study was to evaluate the psychology and psychiatry resources and practices in the 37 specialized obesity centers (CSOs) created by the French Ministry of Health. CSO coordinators were contacted by e-mail to collect general information on the centers (e.g., number of bariatric operations). Secondly, psychologists and psychiatrists of each center completed an anonymous questionnaire assessing their professional practices and their organization of care pathways. The vast majority of CSO coordinators (81%, n = 26/32) answered our survey. These results show significant differences and shortages in terms of the psychology/psychiatry resources available. Most of the psychologists (n = 26/31) and psychiatrists (n = 10/10) stated that they systematically meet new patients only before surgery (56%) or both before and after the operation (30%); however, some psychologists and psychiatrists (14%) do not systematically meet all the patients (before and/or after surgery). Nevertheless, all the professionals provide psychology assessments, and about 75% of them offer a psychological follow-up, indicating a similarity regarding the practices of psychologists and psychiatrists. Our results highlight the place of psychological/psychiatric evaluations in French CSOs and emphasize the absence of mental health providers in several of these services. Post-operative psychological follow-up is not usually provided. It would be appropriate to create clear recommendations for post-operative psychological or psychiatric long-term follow-up.", "title": "Mental Health Support Provided Throughout the Bariatric Surgery Clinical Pathway in French Specialized Care Centers for Obesity" }, { "docid": "27123743", "text": "Breast cancer may originate in utero. We reviewed the available evidence on the association between birthweight and the risk of breast cancer. To date, 26 research papers addressing this issue have been published. The majority of studies identified a positive link between birthweight and premenopausal, but not postmenopausal, breast cancer. The relative risk estimate for breast cancer comparing women with high birthweight to women with low birthweight combining all studies including both pre- and postmenopausal breast cancer was 1.23 (95% confidence interval 1.13-1.34). The mechanisms underlying this association likely include elevated levels of growth factors that may increase the number of susceptible stem cells in the mammary gland or initiate tumors through DNA mutations. Loss of imprinting (LOI) of growth hormone genes relevant for intrauterine growth, such as insulin-like growth factor 2 (IGF2), leads to abnormally high levels of these hormones evidenced by high birthweight. LOI of IGF2 has also been found in mammary tumor tissue. The role of environmental factors that stimulate such epigenetic regulation of gene expression remains to be elucidated.", "title": "Role of birthweight in the etiology of breast cancer." }, { "docid": "16098747", "text": "Evaluate known breast cancer risk factors in relation to breast density. We examined factors in relation to breast density in 144,018 New Hampshire (NH) women with at least one mammogram recorded in a statewide mammography registry. Mammographic breast density was measured by radiologists using the BI-RADS classification; risk factors of interest were obtained from patient intake forms and questionnaires. Initial analyses showed a strong inverse influence of age and body mass index (BMI) on breast density. In addition, women with late age at menarche, late age at first birth, premenopausal women, and those currently using hormone therapy (HT) tended to have higher breast density, while those with greater parity tended to have less dense breasts. Analyses stratified on age and BMI suggested interactions, which were formally assessed in a multivariable model. The impact of current HT use, relative to nonuse, differed across age groups, with an inverse association in younger women, and a positive association in older women (p < 0.0001 for the interaction). The positive effects of age at menarche and age at first birth, and the inverse influence of parity were less apparent in women with low BMI than in those with high BMI (p = 0.04, p < 0.0001 and p = 0.01, respectively, for the interactions). We also noted stronger positive effects for age at first birth in postmenopausal women (p = 0.004 for the interaction). The multivariable model indicated a slight positive influence of family history of breast cancer. The influence of age at menarche and reproductive factors on breast density is less evident in women with high BMI. Density is reduced in young women using HT, but increased in HT users of age 50 or more.", "title": "Breast cancer risk factors in relation to breast density (United States)" }, { "docid": "1428840", "text": "BACKGROUND It has been suggested that identified risk factors for endometrial cancer operate through a single etiologic pathway, i.e., exposure to relatively high levels of unopposed estrogen (estrogen in the absence of progestins). Only a few studies, however, have addressed this issue directly. PURPOSE We assessed the risk of developing endometrial cancer among both premenopausal and postmenopausal women in relation to the circulating levels of steroid hormones and sex hormone-binding globulin (SHBG). The independent effect of hormones was assessed after adjustment for other known risk factors. \n METHODS The data used in the analysis are from a case-control study conducted in five geographic regions in the United States. Incident cases were newly diagnosed during the period from June 1, 1987, through May 15, 1990. The case patients, aged 20-74 years, were matched to control subjects by age, race, and geographic region. The community control subjects were obtained by random-digit-dialing procedures (for subjects 20-64 years old) and from files of the Health Care Financing Administration (for subjects > or = 65 years old). Additional control subjects who were having a hysterectomy performed for benign conditions were obtained from the participating centers. Women reporting use of exogenous estrogens or oral contraceptives within 6 months of interview were excluded, resulting in 68 case patients and 107 control subjects among premenopausal women and 208 case patients and 209 control subjects among postmenopausal women. The hormone analyses were performed on blood samples obtained from case patients or from hysterectomy control subjects before surgery. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by use of an unconditional logistic regression analysis after we controlled for matching variables and potential confounders. All P values were two-sided. \n RESULTS High circulating levels of androstenedione were associated with 3.6-fold and 2.8-fold increased risks among premenopausal and postmenopausal women, respectively, after adjustment for other factors (P for trend = .01 and < .001, respectively). Risks related to other hormone fractions varied by menopausal status. Among postmenopausal women, a reduced risk was associated with high SHBG levels and persisted after adjustment was made for obesity and other factors (OR = 0.51; 95% CI = 0.27-0.95). High estrone levels were associated with increased risk (OR = 3.8; 95% CI = 2.2-6.6), although adjustment for other risk factors (particularly body mass index) diminished the effect (OR = 2.2; 95% CI = 1.2-4.4). Albumin-bound estradiol (E2), a marker of the bioavailable fraction, also remained an important risk factor after adjustment was made for other factors (OR = 2.0; 95% CI = 1.0-3.9). In contrast, high concentrations of total, free, and albumin-bound E2 were unrelated to increased risk in premenopausal women. In both premenopausal and postmenopausal groups, risks associated with obesity and fat distribution were not affected by adjustment for hormones. \n CONCLUSION High endogenous levels of unopposed estrogen are related to increased risk of endometrial cancer, but their independence from other risk factors is inconsistent with being a common underlying biologic pathway through which all risk factors for endometrial cancer operate. IMPLICATIONS Further research should focus on alternative endocrinologic mechanisms for risk associated with obesity and body fat distribution and for the biologic relevance of the increased risk associated with androstenedione in both premenopausal and postmenopausal disease.", "title": "Case-control study of endogenous steroid hormones and endometrial cancer." }, { "docid": "24341590", "text": "CONTEXT The growth inhibitory effect of tamoxifen, which is used for the treatment of hormone receptor-positive breast cancer, is mediated by its metabolites, 4-hydroxytamoxifen and endoxifen. The formation of active metabolites is catalyzed by the polymorphic cytochrome P450 2D6 (CYP2D6) enzyme. \n OBJECTIVE To determine whether CYP2D6 variation is associated with clinical outcomes in women receiving adjuvant tamoxifen. \n DESIGN, SETTING, AND PATIENTS Retrospective analysis of German and US cohorts of patients treated with adjuvant tamoxifen for early stage breast cancer. The 1325 patients had diagnoses between 1986 and 2005 of stage I through III breast cancer and were mainly postmenopausal (95.4%). Last follow-up was in December 2008; inclusion criteria were hormone receptor positivity, no metastatic disease at diagnosis, adjuvant tamoxifen therapy, and no chemotherapy. DNA from tumor tissue or blood was genotyped for CYP2D6 variants associated with reduced (*10, *41) or absent (*3, *4, *5) enzyme activity. Women were classified as having an extensive (n=609), heterozygous extensive/intermediate (n=637), or poor (n=79) CYP2D6 metabolism. \n MAIN OUTCOME MEASURES Time to recurrence, event-free survival, disease-free survival, and overall survival. \n RESULTS Median follow-up was 6.3 years. At 9 years of follow-up, the recurrence rates were 14.9% for extensive metabolizers, 20.9% for heterozygous extensive/intermediate metabolizers, and 29.0% for poor metabolizers, and all-cause mortality rates were 16.7%, 18.0%, and 22.8%, respectively. Compared with extensive metabolizers, there was a significantly increased risk of recurrence for heterozygous extensive/intermediate metabolizers (time to recurrence adjusted hazard ratio [HR], 1.40; 95% confidence interval [CI], 1.04-1.90) and for poor metabolizers (time to recurrence HR, 1.90; 95% CI, 1.10-3.28). Compared with extensive metabolizers, those with decreased CYP2D6 activity (heterozygous extensive/intermediate and poor metabolism) had worse event-free survival (HR, 1.33; 95% CI, 1.06-1.68) and disease-free survival (HR, 1.29; 95% CI, 1.03-1.61), but there was no significant difference in overall survival (HR, 1.15; 95% CI, 0.88-1.51). \n CONCLUSION Among women with breast cancer treated with tamoxifen, there was an association between CYP2D6 variation and clinical outcomes, such that the presence of 2 functional CYP2D6 alleles was associated with better clinical outcomes and the presence of nonfunctional or reduced-function alleles with worse outcomes.", "title": "Association between CYP2D6 polymorphisms and outcomes among women with early stage breast cancer treated with tamoxifen." }, { "docid": "4886637", "text": "Incidences of breast cancer, type 2 diabetes, and metabolic syndrome have increased over the past decades with the obesity epidemic, especially in industrialized countries. Insulin resistance, hyperinsulinemia, and changes in the signaling of growth hormones and steroid hormones associated with diabetes may affect the risk of breast cancer. We reviewed epidemiologic studies of the association between type 2 diabetes and risk of breast cancer and the available evidence on the role of hormonal mediators of an association between diabetes and breast cancer. The combined evidence supports a modest association between type 2 diabetes and the risk of breast cancer, which appears to be more consistent among postmenopausal than among premenopausal women. Despite many proposed potential pathways, the mechanisms underlying an association between diabetes and breast cancer risk remain unclear, particularly because the 2 diseases share several risk factors, including obesity, a sedentary lifestyle, and possibly intake of saturated fat and refined carbohydrates, that may confound this association. Although the metabolic syndrome is closely related to diabetes and embraces additional components that might influence breast cancer risk, the role of the metabolic syndrome in breast carcinogenesis has not been studied and thus remains unknown.", "title": "Diabetes, metabolic syndrome, and breast cancer: a review of the current evidence." }, { "docid": "32534305", "text": "OBJECTIVE Hyperinsulinemia may promote mammary carcinogenesis. Insulin resistance has been linked to an increased risk of breast cancer and is also characteristic of type 2 diabetes. We prospectively evaluated the association between type 2 diabetes and invasive breast cancer incidence in the Nurses' Health Study. RESEARCH DESIGN AND METHODS A total of 116,488 female nurses who were 30-55 years old and free of cancer in 1976 were followed through 1996 for the occurrence of type 2 diabetes and through 1998 for incident invasive breast cancer, verified by medical records and pathology reports. \n RESULTS During 2.3 million person-years of follow-up, we identified 6,220 women with type 2 diabetes and 5,189 incident cases of invasive breast cancer. Women with type 2 diabetes had a modestly elevated incidence of breast cancer (hazard ratio [HR] = 1.17; 95% CI 1.01-1.35) compared with women without diabetes, independent of age, obesity, family history of breast cancer, history of benign breast disease, reproductive factors, physical activity, and alcohol consumption. This association was apparent among postmenopausal women (1.16; 0.98-1.62) but not premenopausal women (0.83; 0.48-1.42). The association was predominant among women with estrogen receptor-positive breast cancer (1.22; 1.01-1.47). \n CONCLUSIONS Women with type 2 diabetes may have a slightly increased risk of breast cancer.", "title": "Type 2 diabetes and subsequent incidence of breast cancer in the Nurses' Health Study." }, { "docid": "5487448", "text": "Birth weight is a significant predictor of breast cancer risk in adult life and mammary gland mass could be an intermediate stage in this long process. We have studied the association of birth size measurements with mammographic density, a marker of mammary gland mass. For a population-based sample of 893 postmenopausal women without previous cancer in Sweden, we retrieved information on birth size from birth records and their most recent mammography. Film mammograms of the medio-lateral oblique view were digitized and the Cumulus software was used for computer-assisted semi-automated thresholding of mammographic density. Results were analyzed using generalized linear models controlling for possible confounders. Mean percent mammographic density increased when comparing the extreme categories of birth weight (from 15.6% to 18.6%) and head circumference (from 15.5% to 20.4%), and the corresponding linear trends were statistically significant (p values 0.02 and 0.007, respectively). The associations were particularly strong when the cutoff for high versus low mammographic density was set at the relatively high value of 50%. Compared to women weighing 3001-3500 grams at birth, women with birth weights >4000g were at almost 3-fold risk of developing high mammographic density (odds ratio: 2.9, 95% confidence interval 1.1 to 7.9). No association with mammographic density was evident with respect to birth length which, however, is known to be less accurately measured. These results indicate that adult breast density, a powerful predictor of breast cancer risk, has intrauterine roots, as reflected in birth size.", "title": "Birth weight and mammographic density among postmenopausal women in Sweden." } ]

[ { "docid": "12670680", "text": "In systemic lupus erythematosus (SLE), self-reactive antibodies can target the kidney (lupus nephritis), leading to functional failure and possible mortality. We report that activation of basophils by autoreactive IgE causes their homing to lymph nodes, promoting T helper type 2 (T(H)2) cell differentiation and enhancing the production of self-reactive antibodies that cause lupus-like nephritis in mice lacking the Src family protein tyrosine kinase Lyn (Lyn(-/-) mice). Individuals with SLE also have elevated serum IgE, self-reactive IgEs and activated basophils that express CD62 ligand (CD62L) and the major histocompatibility complex (MHC) class II molecule human leukocyte antigen-DR (HLA-DR), parameters that are associated with increased disease activity and active lupus nephritis. Basophils were also present in the lymph nodes and spleen of subjects with SLE. Thus, in Lyn(-/-) mice, basophils and IgE autoantibodies amplify autoantibody production that leads to lupus nephritis, and in individuals with SLE IgE autoantibodies and activated basophils are factors associated with disease activity and nephritis.", "title": "BASOPHILS AND THE T HELPER 2 ENVIRONMENT CAN PROMOTE THE DEVELOPMENT OF LUPUS NEPHRITIS" } ]

[ { "docid": "14938990", "text": "Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with complicated genetic inheritance. Programmed death 1 (PD-1), a negative T cell regulator to maintain peripheral tolerance, induces negative signals to T cells during interaction with its ligands and is therefore a candidate gene in the development of SLE. In order to examine whether expression levels of PD-1 contribute to the pathogenesis of SLE, 30 patients with SLE and 30 controls were recruited and their PD-1 expression levels in peripheral blood mononuclear cells (PBMCs) were measured via flow cytometry and quantitative real-time-reverse transcription polymerase chain reaction (RT-PCR). Also, whether PD-1 expression levels are associated with the variant of the SNP rs36084323 and the SLE Disease Activity Index (SLEDAI) was studied in this work. The PD-1 expression levels of SLE patients were significantly increased compared with those of the healthy controls. The upregulated PD-1 expression levels in SLE patients were greatly associated with SLEDAI scores. No significant difference was found between PD-1 expression levels and SNP rs36084323. The results suggest that increased expression of PD-1 may correlate with the pathogenesis of SLE, upregulated PD-1 expression may be a biomarker for SLE diagnosis, and PD-1 inhibitor may be useful to SLE treatment.", "title": "Upregulated PD-1 Expression Is Associated with the Development of Systemic Lupus Erythematosus, but Not the PD-1.1 Allele of the PDCD1 Gene" }, { "docid": "28015516", "text": "Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by a breakdown of tolerance to nuclear antigens and the development of immune complexes. Genomic approaches have shown that human SLE leukocytes homogeneously express type I interferon (IFN)-induced and neutrophil-related transcripts. Increased production and/or bioavailability of IFN-α and associated alterations in dendritic cell (DC) homeostasis have been linked to lupus pathogenesis. Although neutrophils have long been shown to be associated with lupus, their potential role in disease pathogenesis remains elusive. Here, we show that mature SLE neutrophils are primed in vivo by type I IFN and die upon exposure to SLE-derived anti-ribonucleoprotein antibodies, releasing neutrophil extracellular traps (NETs). SLE NETs contain DNA as well as large amounts of LL37 and HMGB1, neutrophil proteins that facilitate the uptake and recognition of mammalian DNA by plasmacytoid DCs (pDCs). Indeed, SLE NETs activate pDCs to produce high levels of IFN-α in a DNA- and TLR9 (Toll-like receptor 9)-dependent manner. Our results reveal an unsuspected role for neutrophils in SLE pathogenesis and identify a novel link between nucleic acid-recognizing antibodies and type I IFN production in this disease.", "title": "Netting neutrophils are major inducers of type I IFN production in pediatric systemic lupus erythematosus." }, { "docid": "28149602", "text": "PURPOSE OF REVIEW Recent discoveries implicate neutrophils as important regulators of innate and adaptive immunity and in the development of organ damage in systemic autoimmune diseases, including systemic lupus erythematosus (SLE). RECENT FINDINGS Various putative SLE biomarkers are neutrophil-related, including neutrophil granular proteins and histones undergoing post-translational modifications during neutrophil extracellular trap (NET) formation. In the bone marrow, lupus neutrophils can drive B and T cell abnormalities, at least in part, by their enhanced production of type-I interferons, tumor necrosis factor-alpha (TNFα) and the B-cell stimulating factors B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL). Lupus neutrophils and, in particular, lupus low-density granulocytes (a distinct pathogenic subset) display epigenetic modifications and genomic alterations that may be relevant to their deleterious roles in SLE. Proteins and enzymes externalized by lupus NETs can affect vascular health by inducing endothelial apoptosis and oxidizing lipoproteins. Hampering NET formation through peptidylarginine deiminase inhibitors abrogates lupus phenotype and atherosclerosis in murine studies. SUMMARY Recent discoveries support the notion that neutrophils, low-density granulocytes and aberrant NET formation and clearance play important roles in lupus pathogenesis. Future studies should focus on how to selectively target these immunostimulatory pathways in this disease.", "title": "The role of neutrophils in the pathogenesis of systemic lupus erythematosus." }, { "docid": "5448119", "text": "Genome-wide association studies have recently identified at least 15 susceptibility loci for systemic lupus erythematosus (SLE). To confirm additional risk loci, we selected SNPs from 2,466 regions that showed nominal evidence of association to SLE (P < 0.05) in a genome-wide study and genotyped them in an independent sample of 1,963 cases and 4,329 controls. This replication effort identified five new SLE susceptibility loci (P < 5 × 10−8): TNIP1 (odds ratio (OR) = 1.27), PRDM1 (OR = 1.20), JAZF1 (OR = 1.20), UHRF1BP1 (OR = 1.17) and IL10 (OR = 1.19). We identified 21 additional candidate loci with P≤ 1 × 10−5. A candidate screen of alleles previously associated with other autoimmune diseases suggested five loci (P < 1 × 10−3) that may contribute to SLE: IFIH1, CFB, CLEC16A, IL12B and SH2B3. These results expand the number of confirmed and candidate SLE susceptibility loci and implicate several key immunologic pathways in SLE pathogenesis.", "title": "A large-scale replication study identifies TNIP1, PRDM1, JAZF1, UHRF1BP1 and IL10 as risk loci for systemic lupus erythematosus" }, { "docid": "1834762", "text": "Research on the human microbiome has established that commensal and pathogenic bacteria can influence obesity, cancer, and autoimmunity through mechanisms mostly unknown. We found that a component of bacterial biofilms, the amyloid protein curli, irreversibly formed fibers with bacterial DNA during biofilm formation. This interaction accelerated amyloid polymerization and created potent immunogenic complexes that activated immune cells, including dendritic cells, to produce cytokines such as type I interferons, which are pathogenic in systemic lupus erythematosus (SLE). When given systemically, curli-DNA composites triggered immune activation and production of autoantibodies in lupus-prone and wild-type mice. We also found that the infection of lupus-prone mice with curli-producing bacteria triggered higher autoantibody titers compared to curli-deficient bacteria. These data provide a mechanism by which the microbiome and biofilm-producing enteric infections may contribute to the progression of SLE and point to a potential molecular target for treatment of autoimmunity.", "title": "Amyloid-DNA Composites of Bacterial Biofilms Stimulate Autoimmunity." }, { "docid": "27466734", "text": "Objectives To develop and validate updated QRISK3 prediction algorithms to estimate the 10 year risk of cardiovascular disease in women and men accounting for potential new risk factors. Design Prospective open cohort study. Setting General practices in England providing data for the QResearch database. Participants 1309 QResearch general practices in England: 981 practices were used to develop the scores and a separate set of 328 practices were used to validate the scores. 7.89 million patients aged 25-84 years were in the derivation cohort and 2.67 million patients in the validation cohort. Patients were free of cardiovascular disease and not prescribed statins at baseline. Methods Cox proportional hazards models in the derivation cohort to derive separate risk equations in men and women for evaluation at 10 years. Risk factors considered included those already in QRISK2 (age, ethnicity, deprivation, systolic blood pressure, body mass index, total cholesterol: high density lipoprotein cholesterol ratio, smoking, family history of coronary heart disease in a first degree relative aged less than 60 years, type 1 diabetes, type 2 diabetes, treated hypertension, rheumatoid arthritis, atrial fibrillation, chronic kidney disease (stage 4 or 5)) and new risk factors (chronic kidney disease (stage 3, 4, or 5), a measure of systolic blood pressure variability (standard deviation of repeated measures), migraine, corticosteroids, systemic lupus erythematosus (SLE), atypical antipsychotics, severe mental illness, and HIV/AIDs). We also considered erectile dysfunction diagnosis or treatment in men. Measures of calibration and discrimination were determined in the validation cohort for men and women separately and for individual subgroups by age group, ethnicity, and baseline disease status. Main outcome measures Incident cardiovascular disease recorded on any of the following three linked data sources: general practice, mortality, or hospital admission records. Results 363 565 incident cases of cardiovascular disease were identified in the derivation cohort during follow-up arising from 50.8 million person years of observation. All new risk factors considered met the model inclusion criteria except for HIV/AIDS, which was not statistically significant. The models had good calibration and high levels of explained variation and discrimination. In women, the algorithm explained 59.6% of the variation in time to diagnosis of cardiovascular disease (R2, with higher values indicating more variation), and the D statistic was 2.48 and Harrell's C statistic was 0.88 (both measures of discrimination, with higher values indicating better discrimination). The corresponding values for men were 54.8%, 2.26, and 0.86. Overall performance of the updated QRISK3 algorithms was similar to the QRISK2 algorithms. Conclusion Updated QRISK3 risk prediction models were developed and validated. The inclusion of additional clinical variables in QRISK3 (chronic kidney disease, a measure of systolic blood pressure variability (standard deviation of repeated measures), migraine, corticosteroids, SLE, atypical antipsychotics, severe mental illness, and erectile dysfunction) can help enable doctors to identify those at most risk of heart disease and stroke.", "title": "Development and validation of QRISK3 risk prediction algorithms to estimate future risk of cardiovascular disease: prospective cohort study" }, { "docid": "14853989", "text": "Autoantibodies to DNA and histones (chromatin) are the defining antigen specificity in systemic lupus erythematosus (SLE) and related musculoskeletal disorders but the mechanisms responsible for their induction remain mysterious. That situation rapidly changed once neutrophil extracellular chromatin traps (NETs) were discovered and observed to play a conserved role in innate immune responses to a broad variety of microbial pathogens. At the center of an infectious process, neutrophils exert various antimicrobial defenses, including the release of nuclear chromatin into the extracellular space. The externalized NETs, a complex meshwork of nuclear chromatin and antimicrobial proteins, serve to immobilize and degrade microbial pathogens. Here, we critically evaluate the evidence supporting NETs versus apoptotic bodies as a source for nuclear antigens in autoimmunity. We also discuss the possibility that NET chromatin forms an essential component of immune deposits in the pathogenesis of glomerulonephritis in SLE and other autoimmune immune complex diseases.", "title": "Neutrophil extracellular chromatin traps connect innate immune response to autoimmunity" }, { "docid": "7115651", "text": "IL-21 is a pleiotropic type 1 cytokine that shares the common cytokine receptor γ-chain, γ(c), with IL-2, IL-4, IL-7, IL-9, and IL-15. IL-21 is most homologous to IL-2. These cytokines are encoded by adjacent genes, but they are functionally distinct. Whereas IL-2 promotes development of regulatory T cells and confers protection from autoimmune disease, IL-21 promotes differentiation of Th17 cells and is implicated in several autoimmune diseases, including type 1 diabetes and systemic lupus erythematosus. However, the roles of IL-21 and IL-2 in CNS autoimmune diseases such as multiple sclerosis and uveitis have been controversial. Here, we generated Il21-mCherry/Il2-emGFP dual-reporter transgenic mice and showed that development of experimental autoimmune uveitis (EAU) correlated with the presence of T cells coexpressing IL-21 and IL-2 into the retina. Furthermore, Il21r(-/-) mice were more resistant to EAU development than wild-type mice, and adoptive transfer of Il21r(-/-) T cells induced much less severe EAU, underscoring the need for IL-21 in the development of this disease and suggesting that blocking IL-21/γ(c)-signaling pathways may provide a means for controlling CNS auto-inflammatory diseases.", "title": "Key role for IL-21 in experimental autoimmune uveitis." }, { "docid": "1049501", "text": "Neutrophil extracellular traps (NETs) are implicated in autoimmunity, but how they are generated and their roles in sterile inflammation remain unclear. Ribonucleoprotein immune complexes (RNP ICs), inducers of NETosis, require mitochondrial reactive oxygen species (ROS) for maximal NET stimulation. After RNP IC stimulation of neutrophils, mitochondria become hypopolarized and translocate to the cell surface. Extracellular release of oxidized mitochondrial DNA is proinflammatory in vitro, and when this DNA is injected into mice, it stimulates type I interferon (IFN) signaling through a pathway dependent on the DNA sensor STING. Mitochondrial ROS are also necessary for spontaneous NETosis of low-density granulocytes from individuals with systemic lupus erythematosus. This was also observed in individuals with chronic granulomatous disease, who lack NADPH oxidase activity but still develop autoimmunity and type I IFN signatures. Mitochondrial ROS inhibition in vivo reduces disease severity and type I IFN responses in a mouse model of lupus. Together, these findings highlight a role for mitochondria in the generation not only of NETs but also of pro-inflammatory oxidized mitochondrial DNA in autoimmune diseases.", "title": "Neutrophil extracellular traps enriched in oxidized mitochondrial DNA are interferogenic and contribute to lupus-like disease" }, { "docid": "13106686", "text": "Immune sensing of DNA is critical for antiviral immunity but can also trigger autoimmune diseases such as lupus erythematosus (LE). Here we have provided evidence for the involvement of a damage-associated DNA modification in the detection of cytosolic DNA. The oxidized base 8-hydroxyguanosine (8-OHG), a marker of oxidative damage in DNA, potentiated cytosolic immune recognition by decreasing its susceptibility to 3' repair exonuclease 1 (TREX1)-mediated degradation. Oxidizative modifications arose physiologically in pathogen DNA during lysosomal reactive oxygen species (ROS) exposure, as well as in neutrophil extracellular trap (NET) DNA during the oxidative burst. 8-OHG was also abundant in UV-exposed skin lesions of LE patients and colocalized with type I interferon (IFN). Injection of oxidized DNA in the skin of lupus-prone mice induced lesions that closely matched respective lesions in patients. Thus, oxidized DNA represents a prototypic damage-associated molecular pattern (DAMP) with important implications for infection, sterile inflammation, and autoimmunity.", "title": "Oxidative damage of DNA confers resistance to cytosolic nuclease TREX1 degradation and potentiates STING-dependent immune sensing." }, { "docid": "5476778", "text": "One hypothesis that couples infection with autoimmune disease is molecular mimicry. Molecular mimicry is characterized by an immune response to an environmental agent that cross-reacts with a host antigen, resulting in disease. This hypothesis has been implicated in the pathogenesis of diabetes, lupus and multiple sclerosis (MS). There is limited direct evidence linking causative agents with pathogenic immune reactions in these diseases. Our study establishes a clear link between viral infection, autoimmunity and neurological disease in humans. As a model for molecular mimicry, we studied patients with human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a disease that can be indistinguishable from MS (refs. 5,6,7). HAM/TSP patients develop antibodies to neurons. We hypothesized these antibodies would identify a central nervous system (CNS) autoantigen. Immunoglobulin G isolated from HAM/TSP patients identified heterogeneous nuclear ribonuclear protein-A1 (hnRNP-A1) as the autoantigen. Antibodies to hnRNP-A1 cross-reacted with HTLV-1-tax, the immune response to which is associated with HAM/TSP (refs. 5,9). Immunoglobulin G specifically stained human Betz cells, whose axons are preferentially damaged. Infusion of autoantibodies in brain sections inhibited neuronal firing, indicative of their pathogenic nature. These data demonstrate the importance of molecular mimicry between an infecting agent and hnRNP-A1 in autoimmune disease of the CNS.", "title": "Autoimmunity due to molecular mimicry as a cause of neurological disease" }, { "docid": "22852120", "text": "Type 2 immune responses are defined by the cytokines interleukin-4 (IL-4), IL-5, IL-9 and IL-13, which can either be host protective or have pathogenic activity. Type 2 immunity promotes antihelminth immunity, suppresses type 1-driven autoimmune disease, neutralizes toxins, maintains metabolic homeostasis, and regulates wound repair and tissue regeneration pathways following infection or injury. Nevertheless, when type 2 responses are dysregulated, they can become important drivers of disease. Type 2 immunity induces a complex inflammatory response characterized by eosinophils, mast cells, basophils, type 2 innate lymphoid cells, IL-4-and/or IL-13-conditioned macrophages and T helper 2 (TH2) cells, which are crucial to the pathogenesis of many allergic and fibrotic disorders. As chronic type 2 immune responses promote disease, the mechanisms that regulate their maintenance are thought to function as crucial disease modifiers. This Review discusses the many endogenous negative regulatory mechanisms that antagonize type 2 immunity and highlights how therapies that target some of these pathways are being developed to treat type 2-mediated disease.", "title": "Type 2 cytokines: mechanisms and therapeutic strategies" }, { "docid": "13717103", "text": "INTRODUCTION Mutations in the FUS gene have been shown to be a rare cause of amyotrophic lateral sclerosis (ALS-FUS) and whilst well documented clinically and genetically there have been relatively few neuropathological studies. Recent work suggested a possible correlation between pathological features such as frequency of basophilic inclusions in neurons and rate of clinical decline, other studies have revealed a discrepancy between the upper motor neuron features detected clinically and the associated pathology. The purpose of this study was to describe the pathological features associated with more recently discovered FUS mutations and reinvestigate those with well recognised mutations in an attempt to correlate the pathology with mutation and/or clinical phenotype. The brains and spinal cords of seven cases of ALS-FUS were examined neuropathologically, including cases with the newly described p. K510E mutation and a case with both a known p. P525L mutation in the FUS gene and a truncating p. Y374X mutation in the TARDBP gene. \n RESULTS The neuropathology in all cases revealed basophilic and FUS inclusions in the cord. The density and type of inclusions varied markedly between cases, but did not allow a clear correlation with clinical progression. Only one case showed significant motor cortical pathology despite the upper motor neuron clinical features being evident in 4 patients. The case with both a FUS and TARDBP mutation revealed FUS positive inclusions but no TDP-43 pathology. Instead there were unusual p62 positive, FUS negative neuronal and glial inclusions as well as dot-like neurites. \n CONCLUSIONS The study confirms cases of ALS-FUS to be mainly a lower motor neuron disease and to have pathology that does not appear to neatly correlate with clinical features or genetics. Furthermore, the case with both a FUS and TARDBP mutation reveals an intriguing pathological profile which at least in part involves a very unusual staining pattern for the ubiquitin-binding protein p62.", "title": "ALS-FUS pathology revisited: singleton FUS mutations and an unusual case with both a FUS and TARDBP mutation" }, { "docid": "18429416", "text": "Food allergy is a major public health concern in westernized countries, estimated to affect 5 % of children and 3–4 % of adults. Allergen-specific immunotherapy for food allergy is currently being actively evaluated, but is still experimental. The optimal protocol, in terms of the route of administration of the food, target maintenance dose, and duration of maintenance therapy, and the optimal patient for these procedures are still being worked out. The mechanisms underlying successful food desensitization are also unclear, in part, because there is no standard immunotherapy protocol. The mechanisms involved, however, may include mast cell and basophil suppression, development of food-specific IgG4 antibodies, reduction in the food-specific IgE/IgG4 ratio, up-regulation and expansion of natural or inducible regulatory T cells, a skewing from a Th2 to a Th1 profile, and the development of anergy and/or deletion in antigen-specific cells. Additional studies are required to elucidate and understand these mechanisms by which desensitization and tolerance are achieved, which may reveal valuable biomarkers for evaluating and following food allergic patients on immunotherapy.", "title": "Immunological mechanisms for desensitization and tolerance in food allergy" }, { "docid": "25726838", "text": "The role of immune responses in tumor development is a central issue for tumor biology and immunology. IL-17 is an important cytokine for inflammatory and autoimmune diseases. Although IL-17-producing cells are detected in cancer patients and tumor-bearing mice, the role of IL-17 in tumor development is controversial, and mechanisms remain to be fully elucidated. In the current study, we found that the development of tumors was inhibited in IL-17R-deficient mice. A defect in IFN-gammaR increased tumor growth, whereas tumor growth was inhibited in mice that were deficient in both IL-17R and IFN-gammaR compared with wild-type animals. Further experiments showed that neutralization of IL-17 by Abs inhibited tumor growth in wild-type mice, whereas systemic administration of IL-17 promoted tumor growth. The IL-17R deficiency increased CD8 T cell infiltration, whereas it reduced the infiltration of myeloid-derived suppressor cells (MDSCs) in tumors. In contrast, administration of IL-17 inhibited CD8 T cell infiltration and increased MDSCs in tumors. Further analysis indicated that IL-17 was required for the development and tumor-promoting activity of MDSCs in tumor-bearing mice. These data demonstrate that IL-17-mediated responses promote tumor development through the induction of tumor-promoting microenvironments at tumor sites. IL-17-mediated regulation of MDSCs is a primary mechanism for its tumor-promoting effects. The study provides novel insights into the role of IL-17 in tumor development and has major implications for targeting IL-17 in treatment of tumors.", "title": "IL-17 promotes tumor development through the induction of tumor promoting microenvironments at tumor sites and myeloid-derived suppressor cells." }, { "docid": "11328820", "text": "The early events leading to the development of rheumatoid arthritis (RA) remain unclear, but formation of autoantibodies to citrullinated protein antigens (ACPAs) is considered a key pathogenic event. Neutrophils isolated from patients with various autoimmune diseases display enhanced neutrophil extracellular trap (NET) formation, a phenomenon that exposes autoantigens in the context of immunostimulatory molecules. We investigated whether aberrant NETosis occurs in RA, determined its triggers, and examined its deleterious inflammatory consequences. Enhanced NETosis was observed in circulating and RA synovial fluid neutrophils compared to neutrophils from healthy controls and from patients with osteoarthritis (OA). Further, netting neutrophils infiltrated RA synovial tissue, rheumatoid nodules, and skin. NETosis correlated with ACPA presence and levels and with systemic inflammatory markers. RA sera and immunoglobulin fractions from RA patients with high levels of ACPA and/or rheumatoid factor significantly enhanced NETosis, and the NETs induced by these autoantibodies displayed distinct protein content. Indeed, during NETosis, neutrophils externalized the citrullinated autoantigens implicated in RA pathogenesis, and anti-citrullinated vimentin antibodies potently induced NET formation. Moreover, the inflammatory cytokines interleukin-17A (IL-17A) and tumor necrosis factor-α (TNF-α) induced NETosis in RA neutrophils. In turn, NETs significantly augmented inflammatory responses in RA and OA synovial fibroblasts, including induction of IL-6, IL-8, chemokines, and adhesion molecules. These observations implicate accelerated NETosis in RA pathogenesis, through externalization of citrullinated autoantigens and immunostimulatory molecules that may promote aberrant adaptive and innate immune responses in the joint and in the periphery, and perpetuate pathogenic mechanisms in this disease.", "title": "NETs are a source of citrullinated autoantigens and stimulate inflammatory responses in rheumatoid arthritis." }, { "docid": "15707049", "text": "Interstitial lung disease (ILD) is a common manifestation of systemic autoimmunity characterized by progressive inflammation or scarring of the lungs. Patients who develop these complications can exhibit significantly impaired gas exchange that may result in hypoxemia, pulmonary hypertension, and even death. Unfortunately, little is understood about how these diseases arise, including the role of specific defects in immune tolerance. Another key question is whether autoimmune responses targeting the lung parenchyma are critical to ILD pathogenesis, including that of isolated idiopathic forms. We show that a specific defect in central tolerance brought about by mutations in the autoimmune regulator gene (Aire) leads to an autoreactive T cell response to a lung antigen named vomeromodulin and the development of ILD. We found that a human patient and mice with defects in Aire develop similar lung pathology, demonstrating that the AIRE-deficient model of autoimmunity is a suitable translational system in which to unravel fundamental mechanisms of ILD pathogenesis.", "title": "Identification of an autoantigen demonstrates a link between interstitial lung disease and a defect in central tolerance." }, { "docid": "19464037", "text": "OBJECTIVE To describe outcomes and identify variables associated with hospital and 1-year survival for patients admitted to an intensive care unit (ICU) with an acute exacerbation of chronic obstructive pulmonary disease (COPD). \n DESIGN Prospective, multicenter, inception cohort study. \n SETTING Forty-two ICUs at 40 US hospitals. \n PATIENTS A total of 362 admissions for COPD exacerbation selected from the Acute Physiology and Chronic Health Evaluation (APACHE) III database of 17,440 ICU admissions. \n MEASUREMENTS AND RESULTS Hospital mortality for the 362 admissions was 24%. For the 167 patients aged 65 years or older, mortality was 30% at hospital discharge, 41% at 90 days, 47% at 180 days, and 59% at 1 year. Median survival for all patients was 224 days, and median survival for the patients who died within 1 year was 30.5 days. On multiple regression analysis, variables associated with hospital mortality included age, severity of respiratory and nonrespiratory organ system dysfunction, and hospital length of stay before ICU admission. Development of nonrespiratory organ system dysfunction was the major predictor of hospital mortality (60% of total explanatory power) and 180-day outcomes (54% of explanatory power). Respiratory physiological variables (respiratory rate, serum pH, PaCO2, PaO2, and alveolar-arterial difference in partial pressure of oxygen [PAO2-PaO2]) indicative of advanced dysfunction were more strongly associated with 180-day mortality rates (22% of explanatory power) than hospital death rates (4% of explanatory power). After controlling for severity of illness, mechanical ventilation at ICU admission was not associated with either hospital mortality or subsequent survival. \n CONCLUSIONS Patients with COPD admitted to an ICU for an acute exacerbation have a substantial hospital mortality (24%). For patients aged 65 years or older, mortality doubles in 1 year from 30% to 59%. Hospital and longer-term mortality is closely associated with development of nonrespiratory organ system dysfunction; severity of the underlying respiratory function substantially influences mortality following hospital discharge. The need for mechanical ventilation at ICU admission did not influence either short- or long-term outcomes. Physicians should be aware of these relationships when making treatment decisions or evaluating new therapies.", "title": "Hospital and 1-year survival of patients admitted to intensive care units with acute exacerbation of chronic obstructive pulmonary disease." }, { "docid": "24712186", "text": "The two membrane proteins, STIM1 and Orai1, have each been shown to be essential for the activation of store-operated channels (SOC). Yet, how these proteins functionally interact is not known. Here, we reveal that STIM1 and Orai1 expressed together reconstitute functional SOCs. Expressed alone, Orai1 strongly reduces store-operated Ca(2+) entry (SOCE) in human embryonic kidney 293 cells and the Ca(2+) release-activated Ca(2+) current (I(CRAC)) in rat basophilic leukemia cells. However, expressed along with the store-sensing STIM1 protein, Orai1 causes a massive increase in SOCE, enhancing the rate of Ca(2+)entry by up to 103-fold. This entry is entirely store-dependent since the same coexpression causes no measurable store-independent Ca(2+) entry. The entry is completely blocked by the SOC blocker, 2-aminoethoxydiphenylborate. Orai1 and STIM1 coexpression also caused a large gain in CRAC channel function in rat basophilic leukemia cells. The close STIM1 homologue, STIM2, inhibited SOCE when expressed alone but coexpressed with Orai1 caused substantial constitutive (store-independent) Ca(2+) entry. STIM proteins are known to mediate Ca(2+) store-sensing and endoplasmic reticulum-plasma membrane coupling with no intrinsic channel properties. Our results revealing a powerful gain in SOC function dependent on the presence of both Orai1 and STIM1 strongly suggest that Orai1 contributes the PM channel component responsible for Ca(2+) entry. The suppression of SOC function by Orai1 overexpression likely reflects a required stoichiometry between STIM1 and Orai1.", "title": "Orai1 and STIM reconstitute store-operated calcium channel function." } ]

[ { "docid": "8126244", "text": "Biogenesis of ribosomes is an essential cellular process conserved across all eukaryotes and is known to require >170 genes for the assembly, modification, and trafficking of ribosome components through multiple cellular compartments. Despite intensive study, this pathway likely involves many additional genes. Here, we employ network-guided genetics-an approach for associating candidate genes with biological processes that capitalizes on recent advances in functional genomic and proteomic studies-to computationally identify additional ribosomal biogenesis genes. We experimentally evaluated >100 candidate yeast genes in a battery of assays, confirming involvement of at least 15 new genes, including previously uncharacterized genes (YDL063C, YIL091C, YOR287C, YOR006C/TSR3, YOL022C/TSR4). We associate the new genes with specific aspects of ribosomal subunit maturation, ribosomal particle association, and ribosomal subunit nuclear export, and we identify genes specifically required for the processing of 5S, 7S, 20S, 27S, and 35S rRNAs. These results reveal new connections between ribosome biogenesis and mRNA splicing and add >10% new genes-most with human orthologs-to the biogenesis pathway, significantly extending our understanding of a universally conserved eukaryotic process.", "title": "Rational Extension of the Ribosome Biogenesis Pathway Using Network-Guided Genetics" } ]

[ { "docid": "20524091", "text": "Self-renewal and differentiation of stem cells are tightly regulated processes subject to intrinsic and extrinsic signals. Molecular chaperones and co-chaperones, especially heat shock proteins (Hsp), are ubiquitous molecules involved in the modulation of protein conformational and complexation states. The function of Hsp, which are typically associated with stress response and tolerance, is well characterized in differentiated cells, while their role in stem cells remains unclear. It appears that embryonic stem cells exhibit increased stress tolerance and concomitant high levels of chaperone expression. This review critically evaluates stem cell research from a molecular chaperone perspective. Furthermore, we propose a model of chaperone-modulated self-renewal in mouse embryonic stem cells.", "title": "Chaperoning stem cells: a role for heat shock proteins in the modulation of stem cell self-renewal and differentiation?" }, { "docid": "8411251", "text": "Histone proteins dynamically regulate chromatin structure and epigenetic signaling to maintain cell homeostasis. These processes require controlled spatial and temporal deposition and eviction of histones by their dedicated chaperones. With the evolution of histone variants, a network of functionally specific histone chaperones has emerged. Molecular details of the determinants of chaperone specificity for different histone variants are only slowly being resolved. A complete understanding of these processes is essential to shed light on the genuine biological roles of histone variants, their chaperones, and their impact on chromatin dynamics.", "title": "The right place at the right time: chaperoning core histone variants." }, { "docid": "20781656", "text": "Some three decades have passed since the discovery of nucleosomes in 1974 and the first isolation of a histone chaperone in 1978. While various types of histone chaperones have been isolated and functionally analyzed, the elementary processes of nucleosome assembly and disassembly have been less well characterized. Recently, the tertiary structure of a hetero-trimeric complex composed of the histone chaperone CIA/ASF1 and the histone H3-H4 dimer was determined, and this complex was proposed to be an intermediate in nucleosome assembly and disassembly reactions. In addition, CIA alone was biochemically shown to dissociate the histone (H3-H4)2 tetramer into two histone H3-H4 dimers. This activity suggested that CIA regulates the semi-conservative replication of nucleosomes. Here, we provide an overview of prominent histone chaperones with the goal of elucidating the mechanisms that preserve and modify epigenetic information. We also discuss the reactions involved in nucleosome assembly and disassembly.", "title": "Histone chaperones: 30 years from isolation to elucidation of the mechanisms of nucleosome assembly and disassembly" }, { "docid": "13907427", "text": "Poly(ADP-ribosyl)ation plays a major role in DNA repair, where it regulates chromatin relaxation as one of the critical events in the repair process. However, the molecular mechanism by which poly(ADP-ribose) modulates chromatin remains poorly understood. Here we identify the poly(ADP-ribose)-regulated protein APLF as a DNA-damage-specific histone chaperone. APLF preferentially binds to the histone H3/H4 tetramer via its C-terminal acidic motif, which is homologous to the motif conserved in the histone chaperones of the NAP1L family (NAP1L motif). We further demonstrate that APLF exhibits histone chaperone activities in a manner that is dependent on its acidic domain and that the NAP1L motif is critical for the repair capacity of APLF in vivo. Finally, we identify structural analogs of APLF in lower eukaryotes with the ability to bind histones and localize to the sites of DNA-damage-induced poly(ADP-ribosyl)ation. Collectively, these findings define the involvement of histone chaperones in poly(ADP-ribose)-regulated DNA repair reactions.", "title": "DNA repair factor APLF is a histone chaperone." }, { "docid": "29877890", "text": "Recent structures of the nucleosome core particle reveal details of histone-histone and histone-DNA interactions. These structures have now set the stage for understanding chromatin assembly and dynamics during replication and transcription. Histone chaperones and chromatin remodeling complexes are important in both of these processes. The nucleosome and its protein core, the histone octamer, have twofold symmetry, which histone chaperones may use to bind core histones. Recent studies suggest that the nucleoplasmin pentamer may mediate histone storage, sperm chromatin decondensation and nucleosome assembly, by dimerizing to form a decamer. In this model, histone binding on the lateral surface of the chaperone involves stereospecific interactions and a shared twofold axis.", "title": "Histone chaperones and nucleosome assembly." }, { "docid": "37164306", "text": "A key event in the mechanism of mouse embryonic stem cell (mESC) pluripotency is phosphorylation, dimerisation and translocation to the nucleus of the signal transducer and activator of transcription3, Stat3. We used RNAi to suppress the levels of the co-chaperone Hsp70/Hsp90 organising protein (Hop) in an mESC line. Hop knockdown caused 68% depletion in Stat3 mRNA levels, decreased soluble pYStat3 levels, and led to an extranuclear accumulation of Stat3. The major binding partner of Hop, Hsp90, co-localised with a small non-nuclear fraction of Stat3 in mESCs, and both Stat3 and Hop co-precipitated with Hsp90. Hop knockdown did not affect Nanog and Oct4 protein levels; however, Nanog mRNA levels were decreased. We found that in the absence of Hop, mESCs lost their pluripotent ability to form embryoid bodies with a basement membrane. These data suggest that Hop facilitates the phosphorylation and nuclear translocation of Stat3, implying a role for the Hsp70/Hsp90 chaperone heterocomplex machinery in pluripotency signalling.", "title": "Knockdown of the co-chaperone Hop promotes extranuclear accumulation of Stat3 in mouse embryonic stem cells." }, { "docid": "30184745", "text": "We have provided a historical perspective on a body of steroid receptor research dealing with the structure and physiological significance of the untransformed 9S receptor that has often confused both novice and expert investigators. The frequent controversies and equivocations of earlier studies were due to the fact that the native, hormone-free state of these receptors is a large multiprotein complex that resisted description for many years because of its unstable and dynamic nature. The untransformed 9S state of the steroid and dioxin receptors has provided a unique system for studying the function of the ubiquitous, abundant, and conserved heat shock protein, hsp90. The hormonal control of receptor association with hsp90 provided a method of manipulating the receptor heterocomplex in a manner that was physiologically meaningful. For several steroid receptors, binding to hsp90 was required for the receptor to be in a native hormone-binding state, and for all of the receptors, hormone binding promoted dissociation of the receptor from hsp90 and conversion of the receptor to the DNA-binding state. Although the complexes between tyrosine kinases and hsp90 were discovered earlier, the hormonal regulation or steroid receptor association with hsp90 permitted much more rapid and facile study of hsp90 function. The observations that hsp90 binds to the receptors through their HBDs and that these domains can be fused to structurally different proteins bringing their function under hormonal control provided a powerful linkage between the hormonal regulation of receptor binding to hsp90 and the initial step in steroid hormone action. Because the 9S receptor hsp90 heterocomplexes could be physically stabilized by molybdate, their protein composition could be readily studied, and it became clear that these complexes are multiprotein structures containing a number of unique proteins, such as FKBP51, FKBP52, CyP-40, and p23, that were discovered because of their presence in these structures. Further analysis showed that hsp90 itself exists in a variety of native multiprotein heterocomplexes independent of steroid receptors and other 'substrate' proteins. Cell-free systems can now be used to study the formation of receptor heterocomplexes. As we outlined in the scheme of Fig. 1, the multicomponent receptor-hsp90 heterocomplex assembly system is being reconstituted, and the importance of individual proteins, such as hsp70, p60, and p23, in the assembly process is becoming recognized. It should be noted that our understanding of the mechanism and purpose of steroid receptor heterocomplex assembly is still at an early stage. We can now speculate on the roles of receptor-associated proteins in receptor action, both as individuals and as a group, but their actual functions are still vague or unknown. We can make realistic models about the chaperoning and trafficking of steroid receptors, but we don't yet know how these processes occur, we don't know where chaperoning occurs in the cell (e.g. Is it limited to the cytoplasm? Is it a diffuse process or does chaperoning occur in association with structural elements?), and, with the exception of the requirement for hormone binding, we don't know the extent to which the hsp90-based chaperone system impacts on steroid hormone action. It is not yet clear how far the discovery of this hsp90 heterocomplex assembly system will be extended to the development of a general understanding of protein processing in the cell. Because this assembly system is apparently present in all eukaryotic cells, it probably performs an essential function for many proteins. The bacterial homolog of hsp90 is not an essential protein, but hsp90 is essential in eukaryotes, and recent studies indicate that the development of the cell nucleus from prokaryotic progenitors was accompanied by the duplication of genes for hsp90 and hsp70 (698). (ABSTRACT TRUNCATED)", "title": "Steroid receptor interactions with heat shock protein and immunophilin chaperones." }, { "docid": "12156187", "text": "The mechanism of activation of the alternative lengthening of telomeres (ALT) pathway of mammalian chromosome-end maintenance has been unclear. We have now discovered that co-depletion of the histone chaperones ASF1a and ASF1b in human cells induced all hallmarks of ALT in both primary and cancer cells. These included the formation of ALT-associated PML (promyelocytic leukemia) bodies (APBs), the presence of extrachromosomal telomeric DNA species, an elevated frequency of telomeric sister chromatid exchanges (t-SCE) events and intertelomeric exchange of an integrated tag. The induction of ALT characteristics in this setting led to the simultaneous suppression of telomerase. We determined that ALT induction is positively regulated by the proteins RAD17 and BLM and negatively regulated by EXO1 and DNA2. The induction of ALT phenotypes as a consequence of ASF1 depletion strongly supports the hypothesis that ALT is a consequence of histone management dysfunction.", "title": "Rapid induction of Alternative Lengthening of Telomeres by depletion of the histone chaperone ASF1" }, { "docid": "12428814", "text": "Secretion systems require high-fidelity mechanisms to discriminate substrates among the vast cytoplasmic pool of proteins. Factors mediating substrate recognition by the type VI secretion system (T6SS) of Gram-negative bacteria, a widespread pathway that translocates effector proteins into target bacterial cells, have not been defined. We report that haemolysin coregulated protein (Hcp), a ring-shaped hexamer secreted by all characterized T6SSs, binds specifically to cognate effector molecules. Electron microscopy analysis of an Hcp-effector complex from Pseudomonas aeruginosa revealed the effector bound to the inner surface of Hcp. Further studies demonstrated that interaction with the Hcp pore is a general requirement for secretion of diverse effectors encompassing several enzymatic classes. Though previous models depict Hcp as a static conduit, our data indicate it is a chaperone and receptor of substrates. These unique functions of a secreted protein highlight fundamental differences between the export mechanism of T6 and other characterized secretory pathways.", "title": "Haemolysin coregulated protein is an exported receptor and chaperone of type VI secretion substrates." }, { "docid": "9889151", "text": "FACT, a heterodimer of Spt16 and Pob3, is an essential histone chaperone. We show that the H2A-H2B binding activity that is central to FACT function resides in short acidic regions near the C termini of each subunit. Mutations throughout these regions affect binding and cause correlated phenotypes that range from mild to lethal, with the largest individual contributions unexpectedly coming from an aromatic residue and a nearby carboxylate residue within each domain. Spt16 and Pob3 bind overlapping sites on H2A-H2B, and Spt16-Pob3 heterodimers simultaneously bind two H2A-H2B dimers, the same stoichiometry as the components of a nucleosome. An Spt16:H2A-H2B crystal structure explains the biochemical and genetic data, provides a model for Pob3 binding, and implies a mechanism for FACT reorganization that we confirm biochemically. Moreover, unexpected similarity to binding of ANP32E and Swr1 with H2A.Z-H2B reveals that diverse H2A-H2B chaperones use common mechanisms of histone binding and regulating nucleosome functions.", "title": "FACT Disrupts Nucleosome Structure by Binding H2A-H2B with Conserved Peptide Motifs." }, { "docid": "1084345", "text": "Chaperone-mediated autophagy (CMA), a selective mechanism for degradation of cytosolic proteins in lysosomes, contributes to the removal of altered proteins as part of the cellular quality-control systems. We have previously found that CMA activity declines in aged organisms and have proposed that this failure in cellular clearance could contribute to the accumulation of altered proteins, the abnormal cellular homeostasis and, eventually, the functional loss characteristic of aged organisms. To determine whether these negative features of aging can be prevented by maintaining efficient autophagic activity until late in life, in this work we have corrected the CMA defect in aged rodents. We have generated a double transgenic mouse model in which the amount of the lysosomal receptor for CMA, previously shown to decrease in abundance with age, can be modulated. We have analyzed in this model the consequences of preventing the age-dependent decrease in receptor abundance in aged rodents at the cellular and organ levels. We show here that CMA activity is maintained until advanced ages if the decrease in the receptor abundance is prevented and that preservation of autophagic activity is associated with lower intracellular accumulation of damaged proteins, better ability to handle protein damage and improved organ function.", "title": "Restoration of chaperone-mediated autophagy in aging liver improves cellular maintenance and hepatic function" }, { "docid": "8538916", "text": "The molecular chaperone CCT/TRiC plays a central role in maintaining cellular proteostasis as it mediates the folding of the major cytoskeletal proteins tubulins and actins. CCT/TRiC is also involved in the oncoprotein cyclin E, the Von Hippel-Lindau tumour suppressor protein, cyclin B and p21(ras) folding which strongly suggests that it is involved in cell proliferation and tumor genesis. To assess the involvement of CCT/TRiC in tumor genesis, we quantified its expression levels and activity in 18 cancer, one non-cancer human cell lines and a non-cancer human liver. We show that the expression levels of CCT/TRiC in cancer cell lines are higher than that in normal cells. However, CCT/TRiC activity does not always correlate with its expression levels. We therefore documented the expression levels of CCT/TRiC modulators and partners PhLP3, Hop/P60, prefoldin and Hsc/Hsp70. Our analysis reveals a functional interplay between molecular chaperones that might account for a precise modulation of CCT/TRiC activity in cell proliferation through changes in the cellular levels of prefoldin and/or Hsc/p70 and CCT/TRiC client protein availability. Our observation and approaches bring novel insights in the role of CCT/TRiC-mediated protein folding machinery in cancer cell development.", "title": "The Cytosolic Chaperonin CCT/TRiC and Cancer Cell Proliferation" }, { "docid": "406733", "text": "In yeast, remodeling of PHO5 promoter chromatin upon activation is accompanied by transient hyperacetylation and subsequent eviction of histones from the promoter in trans. In the course of rerepression, nucleosomes have to be reassembled on the promoter. We have analyzed where the histones for reassembly of the inactive promoter chromatin come from. The use of a strain with two differently tagged and differently regulated versions of histone H3 allowed us to discriminate between histones originating from the chromatin fraction and histones arising from the soluble histone pool. In this way, we show that the incorporated histones originate from a source in trans. Promoter closure occurs very rapidly, and the histone chaperones Asf1 and Hir1 as well as the SWI/SNF nucleosome remodeling complex appear to be important for rapid reassembly of nucleosomes at the PHO5 promoter.", "title": "Histones are incorporated in trans during reassembly of the yeast PHO5 promoter." }, { "docid": "12588500", "text": "Chromatin assembly factor 1 (CAF-1) and Rtt106 participate in the deposition of newly synthesized histones onto replicating DNA to form nucleosomes. This process is critical for the maintenance of genome stability and inheritance of functionally specialized chromatin structures in proliferating cells. However, the molecular functions of the acetylation of newly synthesized histones in this DNA replication-coupled nucleosome assembly pathway remain enigmatic. Here we show that histone H3 acetylated at lysine 56 (H3K56Ac) is incorporated onto replicating DNA and, by increasing the binding affinity of CAF-1 and Rtt106 for histone H3, H3K56Ac enhances the ability of these histone chaperones to assemble DNA into nucleosomes. Genetic analysis indicates that H3K56Ac acts in a nonredundant manner with the acetylation of the N-terminal residues of H3 and H4 in nucleosome assembly. These results reveal a mechanism by which H3K56Ac regulates replication-coupled nucleosome assembly mediated by CAF-1 and Rtt106.", "title": "Acetylation of Histone H3 Lysine 56 Regulates Replication-Coupled Nucleosome Assembly" }, { "docid": "15893330", "text": "Eukaryotic ribosomes assemble by association of ribosomal RNA with ribosomal proteins into nuclear precursor particles, which undergo a complex maturation pathway coordinated by non-ribosomal assembly factors. Here, we provide functional insights into how successive structural re-arrangements in ribosomal protein S3 promote maturation of the 40S ribosomal subunit. We show that S3 dimerizes and is imported into the nucleus with its N-domain in a rotated conformation and associated with the chaperone Yar1. Initial assembly of S3 with 40S precursors occurs via its C-domain, while the N-domain protrudes from the 40S surface. Yar1 is replaced by the assembly factor Ltv1, thereby fixing the S3 N-domain in the rotated orientation and preventing its 40S association. Finally, Ltv1 release, triggered by phosphorylation, and flipping of the S3 N-domain into its final position results in the stable integration of S3. Such a stepwise assembly may represent a new paradigm for the incorporation of ribosomal proteins.", "title": "Sequential domain assembly of ribosomal protein S3 drives 40S subunit maturation." }, { "docid": "6157371", "text": "Actin and its key regulatory component, cofilin, are found together in large rod-shaped assemblies in neurons subjected to energy stress. Such inclusions are also enriched in Alzheimer's disease brain, and appear in transgenic models of neurodegeneration. Neuronal insults, such as energy loss and/or oxidative stress, result in rapid dephosphorylation of the cellular cofilin pool prior to its assembly into rod-shaped inclusions. Although these events implicate a role for phosphatases in cofilin rod formation, a mechanism linking energy stress, phosphocofilin turnover, and subsequent rod assembly has been elusive. We demonstrate the ATP-sensitive interaction of the cofilin phosphatase chronophin (CIN) with the chaperone hsp90 to form a biosensor that mediates cofilin/actin rod formation. Our results suggest a model whereby attenuated interactions between CIN and hsp90 during ATP depletion enhance CIN-dependent cofilin dephosphorylation and consequent rod assembly, thereby providing a mechanism for the formation of pathological actin/cofilin aggregates during neurodegenerative energy flux.", "title": "Chronophin mediates an ATP-sensing mechanism for cofilin dephosphorylation and neuronal cofilin-actin rod formation." }, { "docid": "20725212", "text": "In eukaryotes, three of the four ribosomal RNAs (rRNAs)—the 5.8S, 18S, and 25S/28S rRNAs—are processed from a single pre-rRNA transcript and assembled into ribosomes. The fourth rRNA, the 5S rRNA, is transcribed by RNA polymerase III and is assembled into the 5S ribonucleoprotein particle (RNP), containing ribosomal proteins Rpl5/uL18 and Rpl11/uL5, prior to its incorporation into preribosomes. In mammals, the 5S RNP is also a central regulator of the homeostasis of the tumor suppressor p53. The nucleolar localization of the 5S RNP and its assembly into preribosomes are performed by a specialized complex composed of Rpf2 and Rrs1 in yeast or Bxdc1 and hRrs1 in humans. Here we report the structural and functional characterization of the Rpf2-Rrs1 complex alone, in complex with the 5S RNA, and within pre-60S ribosomes. We show that the Rpf2-Rrs1 complex contains a specialized 5S RNA E-loop-binding module, contacts the Rpl5 protein, and also contacts the ribosome assembly factor Rsa4 and the 25S RNA. We propose that the Rpf2-Rrs1 complex establishes a network of interactions that guide the incorporation of the 5S RNP in preribosomes in the initial conformation prior to its rotation to form the central protuberance found in the mature large ribosomal subunit.", "title": "Chaperoning 5S RNA assembly." }, { "docid": "21380348", "text": "Vitamins are compounds that are essential for the normal growth, reproduction and functioning of the human body. Of the 13 known vitamins, vitamins A, D, E and K are lipophilic compounds and are therefore called fat-soluble vitamins. Because of their lipophilicity, fat-soluble vitamins are solubilized and transported by intracellular carrier proteins to exert their actions and to be metabolized properly. Vitamin A and its derivatives, collectively called retinoids, are solubilized by intracellular retinoid-binding proteins such as cellular retinol-binding protein (CRBP), cellular retinoic acid-binding protein (CRABP) and cellular retinal-binding protein (CRALBP). These proteins act as chaperones that regulate the metabolism, signaling and transport of retinoids. CRALBP-mediated intracellular retinoid transport is essential for vision in human. α-Tocopherol, the main form of vitamin E found in the body, is transported by α-tocopherol transfer protein (α-TTP) in hepatic cells. Defects of α-TTP cause vitamin E deficiency and neurological disorders in humans. Recently, it has been shown that the interaction of α-TTP with phosphoinositides plays a critical role in the intracellular transport of α-tocopherol and is associated with familial vitamin E deficiency. In this review, we summarize the mechanisms and biological significance of the intracellular transport of vitamins A and E.", "title": "Intracellular transport of fat-soluble vitamins A and E." }, { "docid": "25832301", "text": "BACKGROUND Increased expression of the tetraspanin TSPAN7 has been observed in a number of cancers; however, it is unclear how TSPAN7 plays a role in cancer progression. \n METHODS We investigated the expression of TSPAN7 in the haematological malignancy multiple myleoma (MM) and assessed the consequences of TSPAN7 expression in the adhesion, migration and growth of MM plasma cells (PC) in vitro and in bone marrow (BM) homing and tumour growth in vivo. Finally, we characterised the association of TSPAN7 with cell surface partner molecules in vitro. \n RESULTS TSPAN7 was found to be highly expressed at the RNA and protein level in CD138(+) MM PC from approximately 50% of MM patients. TSPAN7 overexpression in the murine myeloma cell line 5TGM1 significantly reduced tumour burden in 5TGM1/KaLwRij mice 4 weeks after intravenous adminstration of 5TGM1 cells. While TSPAN7 overexpression did not affect cell proliferation in vitro, TSPAN7 increased 5TGM1 cell adhesion to BM stromal cells and transendothelial migration. In addition, TSPAN7 was found to associate with the molecular chaperone calnexin on the cell surface. \n CONCLUSION These results suggest that elevated TSPAN7 may be associated with better outcomes for up to 50% of MM patients.", "title": "Tetraspanin 7 (TSPAN7) expression is upregulated in multiple myeloma patients and inhibits myeloma tumour development in vivo." }, { "docid": "30884033", "text": "Deciphering the molecular basis of stem cell pluripotency is fundamental to the understanding of stem cell biology, early embryonic development, and to the clinical application of regenerative medicine. We report here that the molecular chaperone heat shock protein 90 (Hsp90) is essential for mouse embryonic stem cell (ESC) pluripotency through regulating multiple pluripotency factors, including Oct4, Nanog, and signal transducer and activator of transcription 3. Inhibition of Hsp90 by either 17-N-Allylamino-17-demethoxygeldanamycin or miRNA led to ESC differentiation. Overexpression of Hsp90β partially rescued the phenotype; in particular, the levels of Oct4 and Nanog were restored. Notably, Hsp90 associated with Oct4 and Nanog in the same cellular complex and protected them from degradation by the ubiquitin proteasome pathway, suggesting that Oct4 and Nanog are potential novel Hsp90 client proteins. In addition, Hsp90 inhibition reduced the mRNA level of Oct4, but not that of Nanog, indicating that Hsp90 participates in Oct4 mRNA processing or maturation. Hsp90 inhibition also increased expression of some protein markers for mesodermal lineages, implying that Hsp90 suppresses mesodermal differentiation from ESCs. These findings support a new role for Hsp90 in maintaining ESC pluripotency by sustaining the level of multiple pluripotency factors, particularly Oct4 and Nanog.", "title": "Regulation of embryonic stem cell pluripotency by heat shock protein 90." } ]

[ { "docid": "1710116", "text": "We compared conscious and nonconscious processing of briefly flashed words using a visual masking procedure while recording intracranial electroencephalogram (iEEG) in ten patients. Nonconscious processing of masked words was observed in multiple cortical areas, mostly within an early time window (<300 ms), accompanied by induced gamma-band activity, but without coherent long-distance neural activity, suggesting a quickly dissipating feedforward wave. In contrast, conscious processing of unmasked words was characterized by the convergence of four distinct neurophysiological markers: sustained voltage changes, particularly in prefrontal cortex, large increases in spectral power in the gamma band, increases in long-distance phase synchrony in the beta range, and increases in long-range Granger causality. We argue that all of those measures provide distinct windows into the same distributed state of conscious processing. These results have a direct impact on current theoretical discussions concerning the neural correlates of conscious access.", "title": "Converging Intracranial Markers of Conscious Access" } ]

[ { "docid": "6985854", "text": "Speech stimuli give rise to neural activity in the listener that can be observed as waveforms using magnetoencephalography. Although waveforms vary greatly from trial to trial due to activity unrelated to the stimulus, it has been demonstrated that spoken sentences can be discriminated based on theta-band (3-7 Hz) phase patterns in single-trial response waveforms. Furthermore, manipulations of the speech signal envelope and fine structure that reduced intelligibility were found to produce correlated reductions in discrimination performance, suggesting a relationship between theta-band phase patterns and speech comprehension. This study investigates the nature of this relationship, hypothesizing that theta-band phase patterns primarily reflect cortical processing of low-frequency (<40 Hz) modulations present in the acoustic signal and required for intelligibility, rather than processing exclusively related to comprehension (e.g., lexical, syntactic, semantic). Using stimuli that are quite similar to normal spoken sentences in terms of low-frequency modulation characteristics but are unintelligible (i.e., their time-inverted counterparts), we find that discrimination performance based on theta-band phase patterns is equal for both types of stimuli. Consistent with earlier findings, we also observe that whereas theta-band phase patterns differ across stimuli, power patterns do not. We use a simulation model of the single-trial response to spoken sentence stimuli to demonstrate that phase-locked responses to low-frequency modulations of the acoustic signal can account not only for the phase but also for the power results. The simulation offers insight into the interpretation of the empirical results with respect to phase-resetting and power-enhancement models of the evoked response.", "title": "Discrimination of speech stimuli based on neuronal response phase patterns depends on acoustics but not comprehension." }, { "docid": "4340358", "text": "The cellular and molecular mechanisms that enable us to sense cold are not well understood. Insights into this process have come from the use of pharmacological agents, such as menthol, that elicit a cooling sensation. Here we have characterized and cloned a menthol receptor from trigeminal sensory neurons that is also activated by thermal stimuli in the cool to cold range. This cold- and menthol-sensitive receptor, CMR1, is a member of the TRP family of excitatory ion channels, and we propose that it functions as a transducer of cold stimuli in the somatosensory system. These findings, together with our previous identification of the heat-sensitive channels VR1 and VRL-1, demonstrate that TRP channels detect temperatures over a wide range and are the principal sensors of thermal stimuli in the mammalian peripheral nervous system.", "title": "Identification of a cold receptor reveals a general role for TRP channels in thermosensation" }, { "docid": "2947540", "text": "Communication between organelles is crucial for eukaryotic cells to function as one coherent unit. An important means of communication is through membrane contact sites, where two organelles come into close proximity allowing the transport of lipids and small solutes between them. Contact sites are dynamic in size and can change in response to environmental or cellular stimuli; however, how this is regulated has been unclear. Here, we show that Saccharomyces cerevisiae Lam6 resides in several central contact sites: ERMES (ER/mitochondria encounter structure), vCLAMP (vacuole and mitochondria patch), and NVJ (nuclear vacuolar junction). We show that Lam6 is sufficient for expansion of contact sites under physiological conditions and necessary for coordination of contact site size. Given that Lam6 is part of a large protein family and is conserved in vertebrates, our work opens avenues for investigating the underlying principles of organelle communication.", "title": "Lam6 Regulates the Extent of Contacts between Organelles" }, { "docid": "79336156", "text": "In this review, we consider the potential functional role of beta-band oscillations, which at present is not yet well understood. We discuss evidence from recent studies on top-down mechanisms involved in cognitive processing, on the motor system and on the pathophysiology of movement disorders that suggest a unifying hypothesis: beta-band activity seems related to the maintenance of the current sensorimotor or cognitive state. We hypothesize that beta oscillations and/or coupling in the beta-band are expressed more strongly if the maintenance of the status quo is intended or predicted, than if a change is expected. Moreover, we suggest that pathological enhancement of beta-band activity is likely to result in an abnormal persistence of the status quo and a deterioration of flexible behavioural and cognitive control.", "title": "Beta-band oscillations--signalling the status quo?" }, { "docid": "5137019", "text": "HIV-1 replication within macrophages of the CNS often results in cognitive and motor impairment, which is known as HIV-associated dementia (HAD) in its most severe form. IFN-beta suppresses viral replication within these cells during early CNS infection, but the effect is transient. HIV-1 eventually overcomes this protective innate immune response to resume replication through an unknown mechanism, initiating the progression toward HAD. In this article, we show that Suppressor of Cytokine Signaling (SOCS)3, a molecular inhibitor of IFN signaling, may allow HIV-1 to evade innate immunity within the CNS. We found that SOCS3 is elevated in an in vivo SIV/macaque model of HAD and that the pattern of expression correlates with recurrence of viral replication and onset of CNS disease. In vitro, the HIV-1 regulatory protein transactivator of transcription induces SOCS3 in human and murine macrophages in a NF-kappaB-dependent manner. SOCS3 expression attenuates the response of macrophages to IFN-beta at proximal levels of pathway activation and downstream antiviral gene expression and consequently overcomes the inhibitory effect of IFN-beta on HIV-1 replication. These studies indicate that SOCS3 expression, induced by stimuli present in the HIV-1-infected brain, such as transactivator of transcription, inhibits antiviral IFN-beta signaling to enhance HIV-1 replication in macrophages. This consequence of SOCS3 expression in vitro, supported by a correlation with increased viral load and onset of CNS disease in vivo, suggests that SOCS3 may allow HIV-1 to evade the protective innate immune response within the CNS, allowing the recurrence of viral replication and, ultimately, promoting progression toward HAD.", "title": "Suppressor of cytokine signaling 3 inhibits antiviral IFN-beta signaling to enhance HIV-1 replication in macrophages." }, { "docid": "25597580", "text": "New neurons are generated in the adult hippocampus throughout life by neural stem/progenitor cells (NSCs), and neurogenesis is a plastic process responsive to external stimuli. We show that canonical Notch signaling through RBP-J is required for hippocampal neurogenesis. Notch signaling distinguishes morphologically distinct Sox2(+) NSCs, and within these pools subpopulations can shuttle between mitotically active or quiescent. Radial and horizontal NSCs respond selectively to neurogenic stimuli. Physical exercise activates the quiescent radial population whereas epileptic seizures induce expansion of the horizontal NSC pool. Surprisingly, reduced neurogenesis correlates with a loss of active horizontal NSCs in aged mice rather than a total loss of stem cells, and the transition to a quiescent state is reversible to rejuvenate neurogenesis in the brain. The discovery of multiple NSC populations with Notch dependence but selective responses to stimuli and reversible quiescence has important implications for the mechanisms of adaptive learning and also for regenerative therapy.", "title": "Quiescent and active hippocampal neural stem cells with distinct morphologies respond selectively to physiological and pathological stimuli and aging." }, { "docid": "41493639", "text": "Burns are one of the most devastating conditions encountered in medicine. The injury represents an assault on all aspects of the patient, from the physical to the psychological. It affects all ages, from babies to elderly people, and is a problem in both the developed and developing world. All of us have experienced the severe pain that even a small burn can bring. However the pain and distress caused by a large burn are not limited to the immediate event. The visible physical and the invisible psychological scars are long lasting and often lead to chronic disability. Burn injuries represent a diverse and varied challenge to medical and paramedical staff. Correct management requires a skilled multidisciplinary approach that addresses all the problems facing a burn patient. This series provides an overview of the most important aspects of burn injuries for hospital and non-hospital healthcare workers.​workers. Figure 1 Top: Child with 70% full thickness burns, which required resuscitation, intensive care support, and extensive debridement and skin grafting. Left: The same child one year later at a burns camp, having made a good recovery. A reasonable outcome is possible ...", "title": "ABC of burns. Introduction." }, { "docid": "38794814", "text": "The human ability to continuously track dynamic environmental stimuli, in particular speech, is proposed to profit from \"entrainment\" of endogenous neural oscillations, which involves phase reorganization such that \"optimal\" phase comes into line with temporally expected critical events, resulting in improved processing. The current experiment goes beyond previous work in this domain by addressing two thus far unanswered questions. First, how general is neural entrainment to environmental rhythms: Can neural oscillations be entrained by temporal dynamics of ongoing rhythmic stimuli without abrupt onsets? Second, does neural entrainment optimize performance of the perceptual system: Does human auditory perception benefit from neural phase reorganization? In a human electroencephalography study, listeners detected short gaps distributed uniformly with respect to the phase angle of a 3-Hz frequency-modulated stimulus. Listeners' ability to detect gaps in the frequency-modulated sound was not uniformly distributed in time, but clustered in certain preferred phases of the modulation. Moreover, the optimal stimulus phase was individually determined by the neural delta oscillation entrained by the stimulus. Finally, delta phase predicted behavior better than stimulus phase or the event-related potential after the gap. This study demonstrates behavioral benefits of phase realignment in response to frequency-modulated auditory stimuli, overall suggesting that frequency fluctuations in natural environmental input provide a pacing signal for endogenous neural oscillations, thereby influencing perceptual processing.", "title": "Frequency modulation entrains slow neural oscillations and optimizes human listening behavior." }, { "docid": "36111909", "text": "Dendrite shape is considered a defining component of neuronal function. Yet, the mechanisms specifying diverse dendritic morphologies, and the extent to which their function depends on these morphologies, remain unclear. Here, we demonstrate a requirement for the microtubule-severing protein katanin p60-like 1 (Kat-60L1) in regulating the elaborate dendrite morphology and nocifensive functions of Drosophila larval class IV dendritic arborization neurons. Kat-60L1 mutants exhibit diminished responsiveness to noxious mechanical and thermal stimuli. Class IV dendrite branch number and length are also reduced, supporting a correspondence between neuronal function and the full extent of the dendritic arbor. These arborization defects occur particularly in late larval development, and live imaging reveals that Kat-60L1 is required for dynamic, filopodia-like nascent branches to stabilize during this stage. Mutant dendrites exhibit fewer EB1-GFP-labeled microtubules, suggesting that Kat-60L1 increases polymerizing microtubules to establish terminal branch stability and full arbor complexity. Although loss of the related microtubule-severing protein Spastin also reduces the class IV dendrite arbor, microtubule polymerization within dendrites is unaffected. Conversely, Spastin overexpression destroys stable microtubules within these neurons, while Kat-60L1 has no effect. Kat-60L1 thus sculpts the class IV dendritic arbor through microtubule regulatory mechanisms distinct from Spastin. Our data support differential roles of microtubule-severing proteins in regulating neuronal morphology and function, and provide evidence that dendritic arbor development is the product of multiple pathways functioning at distinct developmental stages.", "title": "Katanin p60-like1 promotes microtubule growth and terminal dendrite stability in the larval class IV sensory neurons of Drosophila." }, { "docid": "33986507", "text": "The rapid activation of gene expression in response to stimuli occurs largely through the regulation of RNA polymerase II-dependent transcription. In this Review, we discuss events that occur during the transcription cycle in eukaryotes that are important for the rapid and specific activation of gene expression in response to external stimuli. In addition to regulated recruitment of the transcription machinery to the promoter, it has now been shown that control steps can include chromatin remodelling and the release of paused polymerase. Recent work suggests that some components of signal transduction cascades also play an integral part in activating transcription at target genes.", "title": "Inducible gene expression: diverse regulatory mechanisms" }, { "docid": "718601", "text": "Mammals can taste a wide repertoire of chemosensory stimuli. Two unrelated families of receptors (T1Rs and T2Rs) mediate responses to sweet, amino acids, and bitter compounds. Here, we demonstrate that knockouts of TRPM5, a taste TRP ion channel, or PLCbeta2, a phospholipase C selectively expressed in taste tissue, abolish sweet, amino acid, and bitter taste reception, but do not impact sour or salty tastes. Therefore, despite relying on different receptors, sweet, amino acid, and bitter transduction converge on common signaling molecules. Using PLCbeta2 taste-blind animals, we then examined a fundamental question in taste perception: how taste modalities are encoded at the cellular level. Mice engineered to rescue PLCbeta2 function exclusively in bitter-receptor expressing cells respond normally to bitter tastants but do not taste sweet or amino acid stimuli. Thus, bitter is encoded independently of sweet and amino acids, and taste receptor cells are not broadly tuned across these modalities.", "title": "Coding of Sweet, Bitter, and Umami Tastes Different Receptor Cells Sharing Similar Signaling Pathways" }, { "docid": "24523573", "text": "Previous studies have shown that synchronized beta frequency (14-30 Hz) oscillations in the primary motor cortex are involved in maintaining steady contractions of contralateral arm and hand muscles. However, little is known about the role of postcentral cortical areas in motor maintenance and their patterns of interaction with motor cortex. We investigated the functional relations of beta-synchronized neuronal assemblies in pre- and postcentral areas of two monkeys as they pressed a hand lever during the wait period of a visual discrimination task. By using power and coherence spectral analysis, we identified a beta-synchronized large-scale network linking pre- and postcentral areas. We then used Granger causality spectra to measure directional influences among recording sites. In both monkeys, strong Granger causal influences were observed from primary somatosensory cortex to both motor cortex and inferior posterior parietal cortex, with the latter area also exerting Granger causal influences on motor cortex. Granger causal influences from motor cortex to postcentral sites, however, were weak in one monkey and not observed in the other. These results are the first, to our knowledge, to demonstrate in awake monkeys that synchronized beta oscillations bind multiple sensorimotor areas into a large-scale network during motor maintenance behavior and carry Granger causal influences from primary somatosensory and inferior posterior parietal cortices to motor cortex.", "title": "Beta oscillations in a large-scale sensorimotor cortical network: directional influences revealed by Granger causality." }, { "docid": "15435343", "text": "The inflammasome is a proteolysis complex that generates the active forms of the proinflammatory cytokines interleukin (IL)-1β and IL-18. Inflammasome activation is mediated by NLR proteins that respond to microbial and nonmicrobial stimuli. Among NLRs, NLRP3 senses the widest array of stimuli and enhances adaptive immunity. However, its role in antitumor immunity is unknown. Therefore, we evaluated the function of the NLRP3 inflammasome in the immune response using dendritic cell vaccination against the poorly immunogenic melanoma cell line B16-F10. Vaccination of Nlrp3(-/-) mice led to a relative 4-fold improvement in survival relative to control animals. Immunity depended on CD8(+) T cells and exhibited immune specificity and memory. Increased vaccine efficacy in Nlrp3(-/-) hosts did not reflect differences in dendritic cells but rather differences in myeloid-derived suppressor cells (MDSC). Although Nlrp3 was expressed in MDSCs, the absence of Nlrp3 did not alter either their functional capacity to inhibit T cells or their presence in peripheral lymphoid tissues. Instead, the absence of Nlrp3 caused a 5-fold reduction in the number of tumor-associated MDSCs found in host mice. Adoptive transfer experiments also showed that Nlrp3(-/-) MDSCs were less efficient in reaching the tumor site. Depleting MDSCs with an anti-Gr-1 antibody increased the survival of tumor-bearing wild-type mice but not Nlrp3(-/-) mice. We concluded that Nlrp3 was critical for accumulation of MDSCs in tumors and for inhibition of antitumor T-cell immunity after dendritic cell vaccination. Our findings establish an unexpected role for Nlrp3 in impeding antitumor immune responses, suggesting novel approaches to improve the response to antitumor vaccines by limiting Nlrp3 signaling.", "title": "The inflammasome component NLRP3 impairs antitumor vaccine by enhancing the accumulation of tumor-associated myeloid-derived suppressor cells." }, { "docid": "21626639", "text": "Macrophages play a relevant role in innate and adaptive immunity depending on the balance of the stimuli received. From an analytical and functional point of view, macrophage stimulation can be segregated into three main modes, as follows: innate, classic, and alternative pathways. These differential activations result in the expression of specific sets of genes involved in the release of pro- or anti-inflammatory stimuli. In the present work, we have analyzed whether specific metabolic patterns depend on the signaling pathway activated. A [1,2-(13)C(2)]glucose tracer-based metabolomics approach has been used to characterize the metabolic flux distributions in macrophages stimulated through the classic, innate, and alternative pathways. Using this methodology combined with mass isotopomer distribution analysis of the new formed metabolites, the data show that activated macrophages are essentially glycolytic cells, and a clear cutoff between the classic/innate activation and the alternative pathway exists. Interestingly, macrophage activation through LPS/IFN-gamma or TLR-2, -3, -4, and -9 results in similar flux distribution patterns regardless of the pathway activated. However, stimulation through the alternative pathway has minor metabolic effects. The molecular basis of the differences between these two types of behavior involves a switch in the expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK2) from the liver type-PFK2 to the more active ubiquitous PFK2 isoenzyme, which responds to Hif-1alpha activation and increases fructose-2,6-bisphosphate concentration and the glycolytic flux. However, using macrophages targeted for Hif-1alpha, the switch of PFK2 isoenzymes still occurs in LPS/IFN-gamma-activated macrophages, suggesting that this pathway regulates ubiquitous PFK2 expression through Hif-1alpha-independent mechanisms.", "title": "Substrate fate in activated macrophages: a comparison between innate, classic, and alternative activation." }, { "docid": "109795294", "text": "According to the Web site of the Association for Automatic Identification and Data Capture Technologies [http://www.aimglobal.org/technologies/rfid], \"radio frequency identification (RFID) technology is an automatic way to collect product, place, and time or transaction data quickly and easily without human intervention or error. \" With the ability to track everything from crates of disposable razors to individual peanut-butter jars on the store shelves, RFID technology offers the potential of \"real-time supply chain visibility. \" Promoters of RFID technology feel [C. Humer, 2003] that \"RF tags are to this decade what the Internet was to the 1990's-a promise of radical change in the way business is done. \" However, before the full potential of RFID technology can be realized, several hurdles need to be overcome: reliability, cost, lack of standards, and security. As these hurdles gradually diminish, Wal-Mart publicly embraces the technology.", "title": "Coming soon to a Wal-Mart near you" }, { "docid": "11615242", "text": "CCAAT/enhancer-binding proteins, C/EBPalpha and C/EBPbeta, are required for fat cell differentiation and maturation. Previous studies showed that replacement of C/EBPalpha with C/EBPbeta, generating the beta/beta alleles in the mouse genome, prevents lipid accumulation in white adipose tissue (WAT). In this study, beta/beta mice lived longer and had higher energy expenditure than their control littermates due to increased WAT energy oxidation. The WAT of beta/beta mice was enriched with metabolically active, thermogenic mitochondria known for energy burning. The beta/beta allele exerted its effect through the elevated expression of the G protein alpha stimulatory subunit (Galphas) in WAT. Galphas, when overexpressed in fat-laden 3T3-L1 cells, stimulated mitochondrial biogenesis similar to that seen in the WAT of beta/beta mice, and effectively diminished the stored lipid pool.", "title": "Effect of a C/EBP gene replacement on mitochondrial biogenesis in fat cells." }, { "docid": "25373397", "text": "A new technique has been developed for the facile location of pseudouridylate (psi) residues in any RNA molecule. The method uses two known modification procedures which in combination uniquely identify U residues which have been converted into psi. The first procedure involves reaction of all U-like and G-like residues with N-cyclohexyl-N'-beta-(4-methylmorpholinium)ethylcarbodiimide p-tosylate (CMC), followed by alkaline removal of all CMC groups except those linked to the N3 of psi. This stops reverse transcription, resulting in a gel band which identifies the U residue. The second procedure is uridine-specific hydrazinolysis which cleaves the RNA chain at all U residues and produces a gel band upon reverse transcription. psi residues, being resistant to hydrazinolysis, are not cleaved and do not stop reverse transcription. This leads to the absence of a band at psi residues. The combined method can also distinguish psi from 5-methyluridine, 4-thiouridine, uridine-5-oxyacetic acid, and 2-thio-5-methylaminomethyluridine as shown by treating rRNA and tRNA species known to contain these modified bases at defined sites. By this procedure, four new sites for psi in Escherichia coli 23S RNA were discovered, and one was disproven. The four new sites are at positions 2457, 2504, 2580, and 2605. The erroneous site is at position 2555. These four new psi residues, which are all in or within 2-3 residues of the peptidyltransferase ring, are thus in a position to play a functional and/or structural role at the peptidyltransferase center.(ABSTRACT TRUNCATED AT 250 WORDS)", "title": "Four newly located pseudouridylate residues in Escherichia coli 23S ribosomal RNA are all at the peptidyltransferase center: analysis by the application of a new sequencing technique." }, { "docid": "5403286", "text": "Phosphatidylinositol 3-kinases (PI3Ks) are crucial coordinators of intracellular signalling in response to extracellular stimuli. Hyperactivation of PI3K signalling cascades is one of the most common events in human cancers. In this Review, we discuss recent advances in our knowledge of the roles of specific PI3K isoforms in normal and oncogenic signalling, the different ways in which PI3K can be upregulated, and the current state and future potential of targeting this pathway in the clinic.", "title": "PI3K in cancer: divergent roles of isoforms, modes of activation and therapeutic targeting" }, { "docid": "10624000", "text": "During continuous speech, lip movements provide visual temporal signals that facilitate speech processing. Here, using MEG we directly investigated how these visual signals interact with rhythmic brain activity in participants listening to and seeing the speaker. First, we investigated coherence between oscillatory brain activity and speaker's lip movements and demonstrated significant entrainment in visual cortex. We then used partial coherence to remove contributions of the coherent auditory speech signal from the lip-brain coherence. Comparing this synchronization between different attention conditions revealed that attending visual speech enhances the coherence between activity in visual cortex and the speaker's lips. Further, we identified a significant partial coherence between left motor cortex and lip movements and this partial coherence directly predicted comprehension accuracy. Our results emphasize the importance of visually entrained and attention-modulated rhythmic brain activity for the enhancement of audiovisual speech processing.", "title": "Lip movements entrain the observers’ low-frequency brain oscillations to facilitate speech intelligibility" } ]

[ { "docid": "1710116", "text": "We compared conscious and nonconscious processing of briefly flashed words using a visual masking procedure while recording intracranial electroencephalogram (iEEG) in ten patients. Nonconscious processing of masked words was observed in multiple cortical areas, mostly within an early time window (<300 ms), accompanied by induced gamma-band activity, but without coherent long-distance neural activity, suggesting a quickly dissipating feedforward wave. In contrast, conscious processing of unmasked words was characterized by the convergence of four distinct neurophysiological markers: sustained voltage changes, particularly in prefrontal cortex, large increases in spectral power in the gamma band, increases in long-distance phase synchrony in the beta range, and increases in long-range Granger causality. We argue that all of those measures provide distinct windows into the same distributed state of conscious processing. These results have a direct impact on current theoretical discussions concerning the neural correlates of conscious access.", "title": "Converging Intracranial Markers of Conscious Access" } ]

[ { "docid": "6985854", "text": "Speech stimuli give rise to neural activity in the listener that can be observed as waveforms using magnetoencephalography. Although waveforms vary greatly from trial to trial due to activity unrelated to the stimulus, it has been demonstrated that spoken sentences can be discriminated based on theta-band (3-7 Hz) phase patterns in single-trial response waveforms. Furthermore, manipulations of the speech signal envelope and fine structure that reduced intelligibility were found to produce correlated reductions in discrimination performance, suggesting a relationship between theta-band phase patterns and speech comprehension. This study investigates the nature of this relationship, hypothesizing that theta-band phase patterns primarily reflect cortical processing of low-frequency (<40 Hz) modulations present in the acoustic signal and required for intelligibility, rather than processing exclusively related to comprehension (e.g., lexical, syntactic, semantic). Using stimuli that are quite similar to normal spoken sentences in terms of low-frequency modulation characteristics but are unintelligible (i.e., their time-inverted counterparts), we find that discrimination performance based on theta-band phase patterns is equal for both types of stimuli. Consistent with earlier findings, we also observe that whereas theta-band phase patterns differ across stimuli, power patterns do not. We use a simulation model of the single-trial response to spoken sentence stimuli to demonstrate that phase-locked responses to low-frequency modulations of the acoustic signal can account not only for the phase but also for the power results. The simulation offers insight into the interpretation of the empirical results with respect to phase-resetting and power-enhancement models of the evoked response.", "title": "Discrimination of speech stimuli based on neuronal response phase patterns depends on acoustics but not comprehension." }, { "docid": "5137019", "text": "HIV-1 replication within macrophages of the CNS often results in cognitive and motor impairment, which is known as HIV-associated dementia (HAD) in its most severe form. IFN-beta suppresses viral replication within these cells during early CNS infection, but the effect is transient. HIV-1 eventually overcomes this protective innate immune response to resume replication through an unknown mechanism, initiating the progression toward HAD. In this article, we show that Suppressor of Cytokine Signaling (SOCS)3, a molecular inhibitor of IFN signaling, may allow HIV-1 to evade innate immunity within the CNS. We found that SOCS3 is elevated in an in vivo SIV/macaque model of HAD and that the pattern of expression correlates with recurrence of viral replication and onset of CNS disease. In vitro, the HIV-1 regulatory protein transactivator of transcription induces SOCS3 in human and murine macrophages in a NF-kappaB-dependent manner. SOCS3 expression attenuates the response of macrophages to IFN-beta at proximal levels of pathway activation and downstream antiviral gene expression and consequently overcomes the inhibitory effect of IFN-beta on HIV-1 replication. These studies indicate that SOCS3 expression, induced by stimuli present in the HIV-1-infected brain, such as transactivator of transcription, inhibits antiviral IFN-beta signaling to enhance HIV-1 replication in macrophages. This consequence of SOCS3 expression in vitro, supported by a correlation with increased viral load and onset of CNS disease in vivo, suggests that SOCS3 may allow HIV-1 to evade the protective innate immune response within the CNS, allowing the recurrence of viral replication and, ultimately, promoting progression toward HAD.", "title": "Suppressor of cytokine signaling 3 inhibits antiviral IFN-beta signaling to enhance HIV-1 replication in macrophages." }, { "docid": "79336156", "text": "In this review, we consider the potential functional role of beta-band oscillations, which at present is not yet well understood. We discuss evidence from recent studies on top-down mechanisms involved in cognitive processing, on the motor system and on the pathophysiology of movement disorders that suggest a unifying hypothesis: beta-band activity seems related to the maintenance of the current sensorimotor or cognitive state. We hypothesize that beta oscillations and/or coupling in the beta-band are expressed more strongly if the maintenance of the status quo is intended or predicted, than if a change is expected. Moreover, we suggest that pathological enhancement of beta-band activity is likely to result in an abnormal persistence of the status quo and a deterioration of flexible behavioural and cognitive control.", "title": "Beta-band oscillations--signalling the status quo?" }, { "docid": "4340358", "text": "The cellular and molecular mechanisms that enable us to sense cold are not well understood. Insights into this process have come from the use of pharmacological agents, such as menthol, that elicit a cooling sensation. Here we have characterized and cloned a menthol receptor from trigeminal sensory neurons that is also activated by thermal stimuli in the cool to cold range. This cold- and menthol-sensitive receptor, CMR1, is a member of the TRP family of excitatory ion channels, and we propose that it functions as a transducer of cold stimuli in the somatosensory system. These findings, together with our previous identification of the heat-sensitive channels VR1 and VRL-1, demonstrate that TRP channels detect temperatures over a wide range and are the principal sensors of thermal stimuli in the mammalian peripheral nervous system.", "title": "Identification of a cold receptor reveals a general role for TRP channels in thermosensation" }, { "docid": "2947540", "text": "Communication between organelles is crucial for eukaryotic cells to function as one coherent unit. An important means of communication is through membrane contact sites, where two organelles come into close proximity allowing the transport of lipids and small solutes between them. Contact sites are dynamic in size and can change in response to environmental or cellular stimuli; however, how this is regulated has been unclear. Here, we show that Saccharomyces cerevisiae Lam6 resides in several central contact sites: ERMES (ER/mitochondria encounter structure), vCLAMP (vacuole and mitochondria patch), and NVJ (nuclear vacuolar junction). We show that Lam6 is sufficient for expansion of contact sites under physiological conditions and necessary for coordination of contact site size. Given that Lam6 is part of a large protein family and is conserved in vertebrates, our work opens avenues for investigating the underlying principles of organelle communication.", "title": "Lam6 Regulates the Extent of Contacts between Organelles" }, { "docid": "15435343", "text": "The inflammasome is a proteolysis complex that generates the active forms of the proinflammatory cytokines interleukin (IL)-1β and IL-18. Inflammasome activation is mediated by NLR proteins that respond to microbial and nonmicrobial stimuli. Among NLRs, NLRP3 senses the widest array of stimuli and enhances adaptive immunity. However, its role in antitumor immunity is unknown. Therefore, we evaluated the function of the NLRP3 inflammasome in the immune response using dendritic cell vaccination against the poorly immunogenic melanoma cell line B16-F10. Vaccination of Nlrp3(-/-) mice led to a relative 4-fold improvement in survival relative to control animals. Immunity depended on CD8(+) T cells and exhibited immune specificity and memory. Increased vaccine efficacy in Nlrp3(-/-) hosts did not reflect differences in dendritic cells but rather differences in myeloid-derived suppressor cells (MDSC). Although Nlrp3 was expressed in MDSCs, the absence of Nlrp3 did not alter either their functional capacity to inhibit T cells or their presence in peripheral lymphoid tissues. Instead, the absence of Nlrp3 caused a 5-fold reduction in the number of tumor-associated MDSCs found in host mice. Adoptive transfer experiments also showed that Nlrp3(-/-) MDSCs were less efficient in reaching the tumor site. Depleting MDSCs with an anti-Gr-1 antibody increased the survival of tumor-bearing wild-type mice but not Nlrp3(-/-) mice. We concluded that Nlrp3 was critical for accumulation of MDSCs in tumors and for inhibition of antitumor T-cell immunity after dendritic cell vaccination. Our findings establish an unexpected role for Nlrp3 in impeding antitumor immune responses, suggesting novel approaches to improve the response to antitumor vaccines by limiting Nlrp3 signaling.", "title": "The inflammasome component NLRP3 impairs antitumor vaccine by enhancing the accumulation of tumor-associated myeloid-derived suppressor cells." }, { "docid": "25597580", "text": "New neurons are generated in the adult hippocampus throughout life by neural stem/progenitor cells (NSCs), and neurogenesis is a plastic process responsive to external stimuli. We show that canonical Notch signaling through RBP-J is required for hippocampal neurogenesis. Notch signaling distinguishes morphologically distinct Sox2(+) NSCs, and within these pools subpopulations can shuttle between mitotically active or quiescent. Radial and horizontal NSCs respond selectively to neurogenic stimuli. Physical exercise activates the quiescent radial population whereas epileptic seizures induce expansion of the horizontal NSC pool. Surprisingly, reduced neurogenesis correlates with a loss of active horizontal NSCs in aged mice rather than a total loss of stem cells, and the transition to a quiescent state is reversible to rejuvenate neurogenesis in the brain. The discovery of multiple NSC populations with Notch dependence but selective responses to stimuli and reversible quiescence has important implications for the mechanisms of adaptive learning and also for regenerative therapy.", "title": "Quiescent and active hippocampal neural stem cells with distinct morphologies respond selectively to physiological and pathological stimuli and aging." }, { "docid": "41493639", "text": "Burns are one of the most devastating conditions encountered in medicine. The injury represents an assault on all aspects of the patient, from the physical to the psychological. It affects all ages, from babies to elderly people, and is a problem in both the developed and developing world. All of us have experienced the severe pain that even a small burn can bring. However the pain and distress caused by a large burn are not limited to the immediate event. The visible physical and the invisible psychological scars are long lasting and often lead to chronic disability. Burn injuries represent a diverse and varied challenge to medical and paramedical staff. Correct management requires a skilled multidisciplinary approach that addresses all the problems facing a burn patient. This series provides an overview of the most important aspects of burn injuries for hospital and non-hospital healthcare workers.​workers. Figure 1 Top: Child with 70% full thickness burns, which required resuscitation, intensive care support, and extensive debridement and skin grafting. Left: The same child one year later at a burns camp, having made a good recovery. A reasonable outcome is possible ...", "title": "ABC of burns. Introduction." }, { "docid": "10624000", "text": "During continuous speech, lip movements provide visual temporal signals that facilitate speech processing. Here, using MEG we directly investigated how these visual signals interact with rhythmic brain activity in participants listening to and seeing the speaker. First, we investigated coherence between oscillatory brain activity and speaker's lip movements and demonstrated significant entrainment in visual cortex. We then used partial coherence to remove contributions of the coherent auditory speech signal from the lip-brain coherence. Comparing this synchronization between different attention conditions revealed that attending visual speech enhances the coherence between activity in visual cortex and the speaker's lips. Further, we identified a significant partial coherence between left motor cortex and lip movements and this partial coherence directly predicted comprehension accuracy. Our results emphasize the importance of visually entrained and attention-modulated rhythmic brain activity for the enhancement of audiovisual speech processing.", "title": "Lip movements entrain the observers’ low-frequency brain oscillations to facilitate speech intelligibility" }, { "docid": "38794814", "text": "The human ability to continuously track dynamic environmental stimuli, in particular speech, is proposed to profit from \"entrainment\" of endogenous neural oscillations, which involves phase reorganization such that \"optimal\" phase comes into line with temporally expected critical events, resulting in improved processing. The current experiment goes beyond previous work in this domain by addressing two thus far unanswered questions. First, how general is neural entrainment to environmental rhythms: Can neural oscillations be entrained by temporal dynamics of ongoing rhythmic stimuli without abrupt onsets? Second, does neural entrainment optimize performance of the perceptual system: Does human auditory perception benefit from neural phase reorganization? In a human electroencephalography study, listeners detected short gaps distributed uniformly with respect to the phase angle of a 3-Hz frequency-modulated stimulus. Listeners' ability to detect gaps in the frequency-modulated sound was not uniformly distributed in time, but clustered in certain preferred phases of the modulation. Moreover, the optimal stimulus phase was individually determined by the neural delta oscillation entrained by the stimulus. Finally, delta phase predicted behavior better than stimulus phase or the event-related potential after the gap. This study demonstrates behavioral benefits of phase realignment in response to frequency-modulated auditory stimuli, overall suggesting that frequency fluctuations in natural environmental input provide a pacing signal for endogenous neural oscillations, thereby influencing perceptual processing.", "title": "Frequency modulation entrains slow neural oscillations and optimizes human listening behavior." }, { "docid": "46594244", "text": "In response to a variety of stimuli, dendritic cells (DCs) transform from immature cells specialized for antigen capture into mature cells specialized for T cell stimulation. During maturation, the DCs acquire an enhanced capacity to form and accumulate peptide-MHC (major histocompatibility complex) class II complexes. Here we show that a key mechanism responsible for this alteration was the generalized activation of lysosomal function. In immature DCs, internalized antigens were slowly degraded and inefficiently used for peptide loading. Maturation induced activation of the vacuolar proton pump that enhanced lysosomal acidification and antigen proteolysis, facilitating efficient formation of peptide-MHC class II complexes. Lysosomal function in DCs thus appears to be specialized for the developmentally regulated processing of internalized antigens.", "title": "Activation of lysosomal function during dendritic cell maturation." }, { "docid": "11903247", "text": "Multiple cellular stressors, including activation of the tumour suppressor p53, can stimulate autophagy. Here we show that deletion, depletion or inhibition of p53 can induce autophagy in human, mouse and nematode cells subjected to knockout, knockdown or pharmacological inhibition of p53. Enhanced autophagy improved the survival of p53-deficient cancer cells under conditions of hypoxia and nutrient depletion, allowing them to maintain high ATP levels. Inhibition of p53 led to autophagy in enucleated cells, and cytoplasmic, not nuclear, p53 was able to repress the enhanced autophagy of p53−/− cells. Many different inducers of autophagy (for example, starvation, rapamycin and toxins affecting the endoplasmic reticulum) stimulated proteasome-mediated degradation of p53 through a pathway relying on the E3 ubiquitin ligase HDM2. Inhibition of p53 degradation prevented the activation of autophagy in several cell lines, in response to several distinct stimuli. These results provide evidence of a key signalling pathway that links autophagy to the cancer-associated dysregulation of p53.", "title": "Regulation of autophagy by cytoplasmic p53" }, { "docid": "33986507", "text": "The rapid activation of gene expression in response to stimuli occurs largely through the regulation of RNA polymerase II-dependent transcription. In this Review, we discuss events that occur during the transcription cycle in eukaryotes that are important for the rapid and specific activation of gene expression in response to external stimuli. In addition to regulated recruitment of the transcription machinery to the promoter, it has now been shown that control steps can include chromatin remodelling and the release of paused polymerase. Recent work suggests that some components of signal transduction cascades also play an integral part in activating transcription at target genes.", "title": "Inducible gene expression: diverse regulatory mechanisms" }, { "docid": "21487212", "text": "Ex-FABP, an extracellular fatty acid binding lipocalin, is physiologically expressed by differentiating chicken chondrocytes and myoblasts. Its expression is enhanced after cell treatment with inflammatory stimuli and repressed by anti-inflammatory agents, behaving as an acute phase protein. Chicken liver fragments in culture show enhanced protein expression after bacterial endotoxin treatment. To investigate the biological role of Ex-FABP, we stably transfected proliferating chondrocytes with an expression vector carrying antisense oriented Ex-FABP cDNA. We observed a dramatic loss of cell viability and a strong inhibition of cell proliferation and differentiation. When chondrocytes were transfected with the antisense oriented Ex-FABP cDNA we observed that Ex-FABP down-modulation increased apoptotic cell number. Myoblasts transfected with the same expression vector showed extensive cell death and impaired myotube formation. We suggest that Ex-FABP acts as a constitutive survival protein and that its expression and activation are fundamental to protect chondrocytes from cell death.", "title": "Inhibition of cell proliferation and induction of apoptosis by ExFABP gene targeting." }, { "docid": "718601", "text": "Mammals can taste a wide repertoire of chemosensory stimuli. Two unrelated families of receptors (T1Rs and T2Rs) mediate responses to sweet, amino acids, and bitter compounds. Here, we demonstrate that knockouts of TRPM5, a taste TRP ion channel, or PLCbeta2, a phospholipase C selectively expressed in taste tissue, abolish sweet, amino acid, and bitter taste reception, but do not impact sour or salty tastes. Therefore, despite relying on different receptors, sweet, amino acid, and bitter transduction converge on common signaling molecules. Using PLCbeta2 taste-blind animals, we then examined a fundamental question in taste perception: how taste modalities are encoded at the cellular level. Mice engineered to rescue PLCbeta2 function exclusively in bitter-receptor expressing cells respond normally to bitter tastants but do not taste sweet or amino acid stimuli. Thus, bitter is encoded independently of sweet and amino acids, and taste receptor cells are not broadly tuned across these modalities.", "title": "Coding of Sweet, Bitter, and Umami Tastes Different Receptor Cells Sharing Similar Signaling Pathways" }, { "docid": "18237384", "text": "Induction of tumor-specific immunity requires that dendritic cells (DCs) efficiently capture and present tumor antigens to result in the expansion and activation of tumor-specific cytotoxic T cells. The transition from antigen capture to T cell stimulation requires a maturation signal; in its absence tolerance, rather than immunity may develop. While immune complexes (ICs) are able to enhance antigen capture, they can be poor at inducing DC maturation, naive T cell activation and protective immunity. We now demonstrate that interfering with the inhibitory signal delivered by FcγRIIB on DCs converts ICs to potent maturation agents and results in T cell activation. Applying this approach to immunization with DCs pulsed ex-vivo with ICs, we have generated antigen-specific CD8+ T cells in vivo and achieved efficient protective immunity in a murine melanoma model. These data imply that ICs may normally function to maintain tolerance through the binding to inhibitory FcγRs on DCs, but they can be converted to potent immunogenic stimuli by selective engagement of activating FcγRs. This mechanism suggests a novel approach to the development of tumor vaccines.", "title": "Inducing Tumor Immunity through the Selective Engagement of Activating Fcγ Receptors on Dendritic Cells" }, { "docid": "24523573", "text": "Previous studies have shown that synchronized beta frequency (14-30 Hz) oscillations in the primary motor cortex are involved in maintaining steady contractions of contralateral arm and hand muscles. However, little is known about the role of postcentral cortical areas in motor maintenance and their patterns of interaction with motor cortex. We investigated the functional relations of beta-synchronized neuronal assemblies in pre- and postcentral areas of two monkeys as they pressed a hand lever during the wait period of a visual discrimination task. By using power and coherence spectral analysis, we identified a beta-synchronized large-scale network linking pre- and postcentral areas. We then used Granger causality spectra to measure directional influences among recording sites. In both monkeys, strong Granger causal influences were observed from primary somatosensory cortex to both motor cortex and inferior posterior parietal cortex, with the latter area also exerting Granger causal influences on motor cortex. Granger causal influences from motor cortex to postcentral sites, however, were weak in one monkey and not observed in the other. These results are the first, to our knowledge, to demonstrate in awake monkeys that synchronized beta oscillations bind multiple sensorimotor areas into a large-scale network during motor maintenance behavior and carry Granger causal influences from primary somatosensory and inferior posterior parietal cortices to motor cortex.", "title": "Beta oscillations in a large-scale sensorimotor cortical network: directional influences revealed by Granger causality." }, { "docid": "21626639", "text": "Macrophages play a relevant role in innate and adaptive immunity depending on the balance of the stimuli received. From an analytical and functional point of view, macrophage stimulation can be segregated into three main modes, as follows: innate, classic, and alternative pathways. These differential activations result in the expression of specific sets of genes involved in the release of pro- or anti-inflammatory stimuli. In the present work, we have analyzed whether specific metabolic patterns depend on the signaling pathway activated. A [1,2-(13)C(2)]glucose tracer-based metabolomics approach has been used to characterize the metabolic flux distributions in macrophages stimulated through the classic, innate, and alternative pathways. Using this methodology combined with mass isotopomer distribution analysis of the new formed metabolites, the data show that activated macrophages are essentially glycolytic cells, and a clear cutoff between the classic/innate activation and the alternative pathway exists. Interestingly, macrophage activation through LPS/IFN-gamma or TLR-2, -3, -4, and -9 results in similar flux distribution patterns regardless of the pathway activated. However, stimulation through the alternative pathway has minor metabolic effects. The molecular basis of the differences between these two types of behavior involves a switch in the expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK2) from the liver type-PFK2 to the more active ubiquitous PFK2 isoenzyme, which responds to Hif-1alpha activation and increases fructose-2,6-bisphosphate concentration and the glycolytic flux. However, using macrophages targeted for Hif-1alpha, the switch of PFK2 isoenzymes still occurs in LPS/IFN-gamma-activated macrophages, suggesting that this pathway regulates ubiquitous PFK2 expression through Hif-1alpha-independent mechanisms.", "title": "Substrate fate in activated macrophages: a comparison between innate, classic, and alternative activation." }, { "docid": "25373397", "text": "A new technique has been developed for the facile location of pseudouridylate (psi) residues in any RNA molecule. The method uses two known modification procedures which in combination uniquely identify U residues which have been converted into psi. The first procedure involves reaction of all U-like and G-like residues with N-cyclohexyl-N'-beta-(4-methylmorpholinium)ethylcarbodiimide p-tosylate (CMC), followed by alkaline removal of all CMC groups except those linked to the N3 of psi. This stops reverse transcription, resulting in a gel band which identifies the U residue. The second procedure is uridine-specific hydrazinolysis which cleaves the RNA chain at all U residues and produces a gel band upon reverse transcription. psi residues, being resistant to hydrazinolysis, are not cleaved and do not stop reverse transcription. This leads to the absence of a band at psi residues. The combined method can also distinguish psi from 5-methyluridine, 4-thiouridine, uridine-5-oxyacetic acid, and 2-thio-5-methylaminomethyluridine as shown by treating rRNA and tRNA species known to contain these modified bases at defined sites. By this procedure, four new sites for psi in Escherichia coli 23S RNA were discovered, and one was disproven. The four new sites are at positions 2457, 2504, 2580, and 2605. The erroneous site is at position 2555. These four new psi residues, which are all in or within 2-3 residues of the peptidyltransferase ring, are thus in a position to play a functional and/or structural role at the peptidyltransferase center.(ABSTRACT TRUNCATED AT 250 WORDS)", "title": "Four newly located pseudouridylate residues in Escherichia coli 23S ribosomal RNA are all at the peptidyltransferase center: analysis by the application of a new sequencing technique." } ]

[ { "docid": "32587939", "text": "Endoplasmic reticulum (ER) stress causes pancreatic β-cell dysfunction and contributes to β-cell loss and the progression of type 2 diabetes. Wolfram syndrome 1 (WFS1) has been shown to be an important regulator of the ER stress signalling pathway; however, its role in β-cell function remains unclear. Here we provide evidence that WFS1 is essential for glucose- and glucagon-like peptide 1 (GLP-1)-stimulated cyclic AMP production and regulation of insulin biosynthesis and secretion. Stimulation with glucose causes WFS1 translocation from the ER to the plasma membrane, where it forms a complex with adenylyl cyclase 8 (AC8), an essential cAMP-generating enzyme in the β-cell that integrates glucose and GLP-1 signalling. ER stress and mutant WFS1 inhibit complex formation and activation of AC8, reducing cAMP synthesis and insulin secretion. These findings reveal that an ER-stress-related protein has a distinct role outside the ER regulating both insulin biosynthesis and secretion. The reduction of WFS1 protein on the plasma membrane during ER stress is a contributing factor for β-cell dysfunction and progression of type 2 diabetes.", "title": "Wolfram syndrome 1 and adenylyl cyclase 8 interact at the plasma membrane to regulate insulin production and secretion" } ]

[ { "docid": "25510546", "text": "Increased lipid supply causes beta cell death, which may contribute to reduced beta cell mass in type 2 diabetes. We investigated whether endoplasmic reticulum (ER) stress is necessary for lipid-induced apoptosis in beta cells and also whether ER stress is present in islets of an animal model of diabetes and of humans with type 2 diabetes. Expression of genes involved in ER stress was evaluated in insulin-secreting MIN6 cells exposed to elevated lipids, in islets isolated from db/db mice and in pancreas sections of humans with type 2 diabetes. Overproduction of the ER chaperone heat shock 70 kDa protein 5 (HSPA5, previously known as immunoglobulin heavy chain binding protein [BIP]) was performed to assess whether attenuation of ER stress affected lipid-induced apoptosis. We demonstrated that the pro-apoptotic fatty acid palmitate triggers a comprehensive ER stress response in MIN6 cells, which was virtually absent using non-apoptotic fatty acid oleate. Time-dependent increases in mRNA levels for activating transcription factor 4 (Atf4), DNA-damage inducible transcript 3 (Ddit3, previously known as C/EBP homologous protein [Chop]) and DnaJ homologue (HSP40) C3 (Dnajc3, previously known as p58) correlated with increased apoptosis in palmitate- but not in oleate-treated MIN6 cells. Attenuation of ER stress by overproduction of HSPA5 in MIN6 cells significantly protected against lipid-induced apoptosis. In islets of db/db mice, a variety of marker genes of ER stress were also upregulated. Increased processing (activation) of X-box binding protein 1 (Xbp1) mRNA was also observed, confirming the existence of ER stress. Finally, we observed increased islet protein production of HSPA5, DDIT3, DNAJC3 and BCL2-associated X protein in human pancreas sections of type 2 diabetes subjects. Our results provide evidence that ER stress occurs in type 2 diabetes and is required for aspects of the underlying beta cell failure.", "title": "Endoplasmic reticulum stress contributes to beta cell apoptosis in type 2 diabetes" }, { "docid": "4911006", "text": "Apoptotic cells have long been considered as intrinsically tolerogenic or unable to elicit immune responses specific for dead cell-associated antigens. However, multiple stimuli can trigger a functionally peculiar type of apoptotic demise that does not go unnoticed by the adaptive arm of the immune system, which we named \"immunogenic cell death\" (ICD). ICD is preceded or accompanied by the emission of a series of immunostimulatory damage-associated molecular patterns (DAMPs) in a precise spatiotemporal configuration. Several anticancer agents that have been successfully employed in the clinic for decades, including various chemotherapeutics and radiotherapy, can elicit ICD. Moreover, defects in the components that underlie the capacity of the immune system to perceive cell death as immunogenic negatively influence disease outcome among cancer patients treated with ICD inducers. Thus, ICD has profound clinical and therapeutic implications. Unfortunately, the gold-standard approach to detect ICD relies on vaccination experiments involving immunocompetent murine models and syngeneic cancer cells, an approach that is incompatible with large screening campaigns. Here, we outline strategies conceived to detect surrogate markers of ICD in vitro and to screen large chemical libraries for putative ICD inducers, based on a high-content, high-throughput platform that we recently developed. Such a platform allows for the detection of multiple DAMPs, like cell surface-exposed calreticulin, extracellular ATP and high mobility group box 1 (HMGB1), and/or the processes that underlie their emission, such as endoplasmic reticulum stress, autophagy and necrotic plasma membrane permeabilization. We surmise that this technology will facilitate the development of next-generation anticancer regimens, which kill malignant cells and simultaneously convert them into a cancer-specific therapeutic vaccine.", "title": "Consensus guidelines for the detection of immunogenic cell death." }, { "docid": "13780287", "text": "When cells are activated by calcium-mobilizing agonists at low, physiological concentrations, the resulting calcium signals generally take the form of repetitive regenerative discharges of stored calcium, termed calcium oscillations [1]. These intracellular calcium oscillations have long fascinated biologists as a mode of digitized intracellular signaling. Recent work has highlighted the role of calcium influx as an essential component of calcium oscillations [2]. This influx occurs through a process known as store-operated calcium entry, which is initiated by calcium sensor proteins, STIM1 and STIM2, in the endoplasmic reticulum [3]. STIM2 is activated by changes in endoplasmic reticulum calcium near the resting level, whereas a threshold of calcium depletion is required for STIM1 activation [4]. Here we show that, surprisingly, it is STIM1 and not STIM2 that is exclusively involved in calcium entry during calcium oscillations. The implication is that each oscillation produces a transient drop in endoplasmic reticulum calcium and that this drop is sufficient to transiently activate STIM1. This transient activation of STIM1 can be observed in some cells by total internal reflection fluorescence microscopy. This arrangement nicely provides a clearly defined and unambiguous signaling system, translating a digital calcium release signal into calcium influx that can signal to downstream effectors.", "title": "STIM1 Is a Calcium Sensor Specialized for Digital Signaling" }, { "docid": "29459383", "text": "The major histocompatibility complex class I molecules display peptides (pMHC I) on the cell surface for immune surveillance by CD8(+) T cells. These peptides are generated by proteolysis of intracellular polypeptides by the proteasome in the cytoplasm and then in the endoplasmic reticulum (ER) by the ER aminopeptidase associated with antigen processing (ERAAP). To define the unknown mechanism of ERAAP function in vivo, we analyzed naturally processed peptides in cells with or without appropriate MHC I and ERAAP. In the absence of MHC I, ERAAP degraded the antigenic precursors in the ER. However, MHC I molecules could bind proteolytic intermediates and were essential for generation of the final peptide by ERAAP. Thus, ERAAP synergizes with MHC I to generate the final pMHC I repertoire.", "title": "ERAAP synergizes with MHC class I molecules to make the final cut in the antigenic peptide precursors in the endoplasmic reticulum." }, { "docid": "4399311", "text": "An inflammatory response initiated by the NLRP3 inflammasome is triggered by a variety of situations of host ‘danger’, including infection and metabolic dysregulation. Previous studies suggested that NLRP3 inflammasome activity is negatively regulated by autophagy and positively regulated by reactive oxygen species (ROS) derived from an uncharacterized organelle. Here we show that mitophagy/autophagy blockade leads to the accumulation of damaged, ROS-generating mitochondria, and this in turn activates the NLRP3 inflammasome. Resting NLRP3 localizes to endoplasmic reticulum structures, whereas on inflammasome activation both NLRP3 and its adaptor ASC redistribute to the perinuclear space where they co-localize with endoplasmic reticulum and mitochondria organelle clusters. Notably, both ROS generation and inflammasome activation are suppressed when mitochondrial activity is dysregulated by inhibition of the voltage-dependent anion channel. This indicates that NLRP3 inflammasome senses mitochondrial dysfunction and may explain the frequent association of mitochondrial damage with inflammatory diseases.", "title": "A role for mitochondria in NLRP3 inflammasome activation" }, { "docid": "19561411", "text": "Orai1 and stromal interaction molecule 1 (STIM1) mediate store-operated Ca(2+) entry (SOCE) in immune cells. STIM1, an endoplasmic reticulum (ER) Ca(2+) sensor, detects store depletion and interacts with plasma membrane (PM)-resident Orai1 channels at the ER-PM junctions. However, the molecular composition of these junctions in T cells remains poorly understood. Here, we show that junctophilin-4 (JP4), a member of junctional proteins in excitable cells, is expressed in T cells and localized at the ER-PM junctions to regulate Ca(2+) signaling. Silencing or genetic manipulation of JP4 decreased ER Ca(2+) content and SOCE in T cells, impaired activation of the nuclear factor of activated T cells (NFAT) and extracellular signaling-related kinase (ERK) signaling pathways, and diminished expression of activation markers and cytokines. Mechanistically, JP4 directly interacted with STIM1 via its cytoplasmic domain and facilitated its recruitment into the junctions. Accordingly, expression of this cytoplasmic fragment of JP4 inhibited SOCE. Furthermore, JP4 also formed a complex with junctate, a Ca(2+)-sensing ER-resident protein, previously shown to mediate STIM1 recruitment into the junctions. We propose that the junctate-JP4 complex located at the junctions cooperatively interacts with STIM1 to maintain ER Ca(2+) homeostasis and mediate SOCE in T cells.", "title": "Junctophilin-4, a component of the endoplasmic reticulum-plasma membrane junctions, regulates Ca2+ dynamics in T cells." }, { "docid": "20904154", "text": "Cu/Zn-superoxide dismutase is misfolded in familial and sporadic amyotrophic lateral sclerosis, but it is not clear how this triggers endoplasmic reticulum (ER) stress or other pathogenic processes. Here, we demonstrate that mutant SOD1 (mSOD1) is predominantly found in the cytoplasm in neuronal cells. Furthermore, we show that mSOD1 inhibits secretory protein transport from the ER to Golgi apparatus. ER-Golgi transport is linked to ER stress, Golgi fragmentation and axonal transport and we also show that inhibition of ER-Golgi trafficking preceded ER stress, Golgi fragmentation, protein aggregation and apoptosis in cells expressing mSOD1. Restoration of ER-Golgi transport by over-expression of coatomer coat protein II subunit Sar1 protected against inclusion formation and apoptosis, thus linking dysfunction in ER-Golgi transport to cellular pathology. These findings thus link several cellular events in amyotrophic lateral sclerosis into a single mechanism occurring early in mSOD1 expressing cells.", "title": "Mutant SOD1 inhibits ER-Golgi transport in amyotrophic lateral sclerosis." }, { "docid": "7482674", "text": "Pelizaeus-Merzbacher disease (PMD) is a form of X-linked leukodystrophy caused by mutations in the proteolipid protein 1 (PLP1) gene. Although PLP1 proteins with missense mutations have been shown to accumulate in the rough endoplasmic reticulum (ER) in disease model animals and cell lines transfected with mutant PLP1 genes, the exact pathogenetic mechanism of PMD has not previously been clarified. In this study, we established induced pluripotent stem cells (iPSCs) from two PMD patients carrying missense mutation and differentiated them into oligodendrocytes in vitro. In the PMD iPSC-derived oligodendrocytes, mislocalization of mutant PLP1 proteins to the ER and an association between increased susceptibility to ER stress and increased numbers of apoptotic oligodendrocytes were observed. Moreover, electron microscopic analysis demonstrated drastically reduced myelin formation accompanied by abnormal ER morphology. Thus, this study demonstrates the involvement of ER stress in pathogenic dysmyelination in the oligodendrocytes of PMD patients with the PLP1 missense mutation.", "title": "Involvement of ER Stress in Dysmyelination of Pelizaeus-Merzbacher Disease with PLP1 Missense Mutations Shown by iPSC-Derived Oligodendrocytes" }, { "docid": "13958154", "text": "Pancreatic β-cell dysfunction and death are central in the pathogenesis of type 2 diabetes (T2D). Saturated fatty acids cause β-cell failure and contribute to diabetes development in genetically predisposed individuals. Here we used RNA sequencing to map transcripts expressed in five palmitate-treated human islet preparations, observing 1,325 modified genes. Palmitate induced fatty acid metabolism and endoplasmic reticulum (ER) stress. Functional studies identified novel mediators of adaptive ER stress signaling. Palmitate modified genes regulating ubiquitin and proteasome function, autophagy, and apoptosis. Inhibition of autophagic flux and lysosome function contributed to lipotoxicity. Palmitate inhibited transcription factors controlling β-cell phenotype, including PAX4 and GATA6. Fifty-nine T2D candidate genes were expressed in human islets, and 11 were modified by palmitate. Palmitate modified expression of 17 splicing factors and shifted alternative splicing of 3,525 transcripts. Ingenuity Pathway Analysis of modified transcripts and genes confirmed that top changed functions related to cell death. Database for Annotation, Visualization and Integrated Discovery (DAVID) analysis of transcription factor binding sites in palmitate-modified transcripts revealed a role for PAX4, GATA, and the ER stress response regulators XBP1 and ATF6. This human islet transcriptome study identified novel mechanisms of palmitate-induced β-cell dysfunction and death. The data point to cross talk between metabolic stress and candidate genes at the β-cell level.", "title": "RNA sequencing identifies dysregulation of the human pancreatic islet transcriptome by the saturated fatty acid palmitate." }, { "docid": "19708993", "text": "Mucolipidosis type IV is an autosomal recessive lysosomal storage disorder characterized by severe neurodegeneration, achlorhydria, and visual impairments such as corneal opacity and strabismus. The disease arises due to mutations in a group 2 transient receptor potential (TRP)-related cation channel, TRPML1. Mammals encode two additional TRPML proteins named TRPML2 and TRPML3. Information regarding the propensity of these proteins to multimerize, their subcellular distribution and mechanisms that regulate their trafficking are limited. Here we demonstrate that TRPMLs interact to form homo- and heteromultimers. Moreover, the presence of either TRPML1 or TRPML2 specifically influences the spatial distribution of TRPML3. TRPML1 and TRPML2 homomultimers are lysosomal proteins, whereas TRPML3 homomultimers are in the endoplasmic reticulum. However, TRPML3 localizes to lysosomes when coexpressed with either TRPML1 or TRPML2 and is comparably mislocalized when lysosomal targeting of TRPML1 and TRPML2 is disrupted. Conversely, TRPML3 does not cause retention of TRPML1 or TRPML2 in the endoplasmic reticulum. These data demonstrate that there is a hierarchy controlling the subcellular distributions of the TRPMLs such that TRPML1 and TRPML2 dictate the localization of TRPML3 and not vice versa.", "title": "Lysosomal localization of TRPML3 depends on TRPML2 and the mucolipidosis-associated protein TRPML1." }, { "docid": "8453819", "text": "The integrin family of heterodimeric cell-surface receptors are fundamental in cell-cell and cell-matrix adhesion. Changes to either integrin-ligand affinity or integrin gene expression are central to a variety of disease processes, including inflammation, cardiovascular disease and cancer. In screening for novel activators of integrin-ligand affinity we identified the previously uncharacterised multi-transmembrane domain protein Fam38A, located at the endoplasmic reticulum (ER). siRNA knockdown of Fam38A in epithelial cells inactivates endogenous beta1 integrin, reducing cell adhesion. Fam38A mediates integrin activation by recruiting the small GTPase R-Ras to the ER, which activates the calcium-activated protease calpain by increasing Ca(2+) release from cytoplasmic stores. Fam38A-induced integrin activation is blocked by inhibition of either R-Ras or calpain activity, or by siRNA knockdown of talin, a well-described calpain substrate. This highlights a novel mechanism for integrin activation by Fam38A, utilising calpain and R-Ras signalling from the ER. These data represent the first description of a novel spatial regulator of R-Ras, of an alternative integrin activation-suppression pathway based on direct relocalisation of R-Ras to the ER, and of a mechanism linking R-Ras and calpain signalling from the ER with modulation of integrin-ligand affinity.", "title": "Integrin activation by Fam38A uses a novel mechanism of R-Ras targeting to the endoplasmic reticulum." }, { "docid": "9752604", "text": "In light of the emerging interplay between redox and metabolic signaling pathways we investigated the potential cross talk between nuclear factor E2-related factor 2 (Nrf2) and AMP-activated kinase (AMPK), central regulators of the cellular redox and energy balance, respectively. Making use of xanthohumol (XN) as an activator of both the AMPK and the Nrf2 signaling pathway we show that AMPK exerts a positive influence on Nrf2/heme oxygenase (HO)-1 signaling in mouse embryonic fibroblasts. Genetic ablation and pharmacological inhibition of AMPK blunts Nrf2-dependent HO-1 expression by XN already at the mRNA level. XN leads to AMPK activation via interference with mitochondrial function and activation of liver kinase B1 as upstream AMPK kinase. The subsequent AMPK-mediated enhancement of the Nrf2/HO-1 response does not depend on inhibition of the mammalian target of rapamycin, inhibition of glycogen synthase kinase 3β, or altered abundance of Nrf2 (total and nuclear). However, reduced endoplasmic reticulum stress was identified and elaborated as a step in the AMPK-augmented Nrf2/HO-1 response. Overall, we shed more light on the hitherto incompletely understood cross talk between the LKB1/AMPK and the Nrf2/HO-1 axis revealing for the first time involvement of the unfolded protein response as an additional player and suggesting tight cooperation between signaling pathways controlling cellular redox, energy, or protein homeostasis.", "title": "Activated AMPK boosts the Nrf2/HO-1 signaling axis—A role for the unfolded protein response" }, { "docid": "15716328", "text": "Endoplasmic reticulum (ER)-associated aminopeptidase (ERAP)1 has been implicated in the final proteolytic processing of peptides presented by major histocompatibility complex (MHC) class I molecules. To evaluate the in vivo role of ERAP1, we have generated ERAP1-deficient mice. Cell surface expression of the class Ia molecules H-2Kb and H-2Db and of the class Ib molecule Qa-2 was significantly reduced in these animals. Although cells from mutant animals exhibited reduced capacity to present several self- and foreign antigens to Kb-, Db-, or Qa-1b–restricted CD8+ cytotoxic T cells, presentation of some antigens was unaffected or significantly enhanced. Consistent with these findings, mice generated defective CD8+ T cell responses against class I–presented antigens. These findings reveal an important in vivo role of ER-associated peptidase activity in tailoring peptides for presentation by MHC class Ia and class Ib molecules.", "title": "In vivo role of ER-associated peptidase activity in tailoring peptides for presentation by MHC class Ia and class Ib molecules" }, { "docid": "38477436", "text": "Human cytomegalovirus US2 and US11 target newly synthesized class I major histocompatibility complex (MHC) heavy chains for rapid degradation by the proteasome through a process termed dislocation. The presence of US2 induces the formation of class I MHC heavy chain conjugates of increased molecular weight that are recognized by a conformation-specific monoclonal antibody, W6/32, suggesting that these class I MHC molecules retain their proper tertiary structure. These conjugates are properly folded glycosylated heavy chains modified by attachment of an estimated one, two, and three ubiquitin molecules. The folded ubiquitinated class I MHC heavy chains are not observed in control cells or in cells transfected with US11, suggesting that US2 targets class I MHC heavy chains for dislocation in a manner distinct from that used by US11. This is further supported by the fact that US2 and US11 show different requirements in terms of the conformation of the heavy chain molecule. Although ubiquitin conjugation may occur on the cytosolic tail of the class I MHC molecule, replacement of lysines in the cytosolic tail of heavy chains with arginine does not prevent their degradation by US2. In an in vitro system that recapitulates US2-mediated dislocation, heavy chains that lack these lysines still occur in an ubiquitin-modified form, but in the soluble (cytoplasmic) fraction. Such ubiquitin conjugation can only occur on the class I MHC lumenal domain and is likely to take place once class I MHC heavy chains have been discharged from the endoplasmic reticulum. We conclude that ubiquitinylation of class I MHC heavy chain is not required during the initial step of the US2-mediated dislocation reaction.", "title": "Ubiquitinylation of the cytosolic domain of a type I membrane protein is not required to initiate its dislocation from the endoplasmic reticulum." }, { "docid": "42873134", "text": "Type 1 and type 2 diabetes are characterized by progressive beta-cell failure. Apoptosis is probably the main form of beta-cell death in both forms of the disease. It has been suggested that the mechanisms leading to nutrient- and cytokine-induced beta-cell death in type 2 and type 1 diabetes, respectively, share the activation of a final common pathway involving interleukin (IL)-1beta, nuclear factor (NF)-kappaB, and Fas. We review herein the similarities and differences between the mechanisms of beta-cell death in type 1 and type 2 diabetes. In the insulitis lesion in type 1 diabetes, invading immune cells produce cytokines, such as IL-1beta, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma. IL-1beta and/or TNF-alpha plus IFN-gamma induce beta-cell apoptosis via the activation of beta-cell gene networks under the control of the transcription factors NF-kappaB and STAT-1. NF-kappaB activation leads to production of nitric oxide (NO) and chemokines and depletion of endoplasmic reticulum (ER) calcium. The execution of beta-cell death occurs through activation of mitogen-activated protein kinases, via triggering of ER stress and by the release of mitochondrial death signals. Chronic exposure to elevated levels of glucose and free fatty acids (FFAs) causes beta-cell dysfunction and may induce beta-cell apoptosis in type 2 diabetes. Exposure to high glucose has dual effects, triggering initially \"glucose hypersensitization\" and later apoptosis, via different mechanisms. High glucose, however, does not induce or activate IL-1beta, NF-kappaB, or inducible nitric oxide synthase in rat or human beta-cells in vitro or in vivo in Psammomys obesus. FFAs may cause beta-cell apoptosis via ER stress, which is NF-kappaB and NO independent. Thus, cytokines and nutrients trigger beta-cell death by fundamentally different mechanisms, namely an NF-kappaB-dependent mechanism that culminates in caspase-3 activation for cytokines and an NF-kappaB-independent mechanism for nutrients. This argues against a unifying hypothesis for the mechanisms of beta-cell death in type 1 and type 2 diabetes and suggests that different approaches will be required to prevent beta-cell death in type 1 and type 2 diabetes.", "title": "Mechanisms of pancreatic beta-cell death in type 1 and type 2 diabetes: many differences, few similarities." }, { "docid": "600437", "text": "VAP (VAPA and VAPB) is an evolutionarily conserved endoplasmic reticulum (ER)-anchored protein that helps generate tethers between the ER and other membranes through which lipids are exchanged across adjacent bilayers. Here, we report that by regulating PI4P levels on endosomes, VAP affects WASH-dependent actin nucleation on these organelles and the function of the retromer, a protein coat responsible for endosome-to-Golgi traffic. VAP is recruited to retromer budding sites on endosomes via an interaction with the retromer SNX2 subunit. Cells lacking VAP accumulate high levels of PI4P, actin comets, and trans-Golgi proteins on endosomes. Such defects are mimicked by downregulation of OSBP, a VAP interactor and PI4P transporter that participates in VAP-dependent ER-endosomes tethers. These results reveal a role of PI4P in retromer-/WASH-dependent budding from endosomes. Collectively, our data show how the ER can control budding dynamics and association with the cytoskeleton of another membrane by direct contacts leading to bilayer lipid modifications.", "title": "Endosome-ER Contacts Control Actin Nucleation and Retromer Function through VAP-Dependent Regulation of PI4P" }, { "docid": "24670522", "text": "The intracellular Ca(2+) concentration of many nonexcitable cells is regulated by calcium store release and store-operated calcium entry (SOCE). In platelets, STIM1 was recently identified as the main calcium sensor expressed in the endoplasmic reticulum. To evaluate the role of the SOC channel moiety, Orai1, in platelet SOCE, we generated mice expressing a mutated, inactive form of Orai1 in blood cells only (Orai1(R93W)). Platelets expressing Orai1(R93W) were characterized by markedly reduced SOCE and impaired agonist-induced increases in [Ca(2+)](i). Orai1(R93W) platelets showed reduced integrin activation and impaired degranulation when stimulated with low agonist concentrations under static conditions. This defect, however, did not significantly affect the ability of Orai1(R93W) platelets to aggregate or to adhere to collagen under arterial flow conditions ex vivo. In contrast, these adherent Orai1(R93W) platelets were defective in surface phosphatidylserine exposure, suggesting that Orai1 is crucial for the platelets' procoagulant response rather than for other Ca(2+)-dependent cellular responses.", "title": "R93W mutation in Orai1 causes impaired calcium influx in platelets." }, { "docid": "2727303", "text": "Stromal-interaction molecule 1 (STIM1) is an endoplasmic reticulum Ca(2+) storage sensor that promotes cell growth, migration, and angiogenesis in breast and cervical cancers. Here, we report that the microtubule-associated histone deacetylase 6 (HDAC6) differentially regulates activation of STIM1-mediated store-operated Ca(2+) entry (SOCE) between cervical cancer cells and normal cervical epithelial cells. Confocal microscopy of living cells indicated that microtubule integrity was necessary for STIM1 trafficking to the plasma membrane and interaction with Orai1, an essential pore subunit of SOCE. Cancer cells overexpressed both STIM1 and Orai1 compared with normal cervical epithelial cells. HDAC6 upregulation in cancer cells was accompanied by hypoacetylated α-tubulin. Tubastatin-A, a specific HDAC6 inhibitor, inhibited STIM1 translocation to plasma membrane and blocked SOCE activation in cancer cells but not normal epithelial cells. Genetic or pharmacologic inhibition of HDAC6 blocked STIM1 membrane trafficking and downstream Ca(2+) influx, as evidenced by total internal reflection fluorescent images and intracellular Ca(2+) determination. In contrast, HDAC6 inhibition did not affect interactions between STIM1 and the microtubule plus end-binding protein EB1. Analysis of surgical specimens confirmed that most cervical cancer tissues overexpressed STIM1 and Orai1, accompanied by hypoacetylated α-tubulin. Together, our results identify HDAC6 as a candidate target to disrupt STIM1-mediated SOCE as a general strategy to block malignant cell behavior.", "title": "Microtubule-associated histone deacetylase 6 supports the calcium store sensor STIM1 in mediating malignant cell behaviors." }, { "docid": "3591070", "text": "Sterol transport between the endoplasmic reticulum (ER) and plasma membrane (PM) occurs by nonvesicular mechanisms requiring sterol transport proteins (STPs). Here we examine the idea that transport is enhanced at membrane contact sites where the ER is closely apposed to the PM. We conclude that sterol desorption from the membrane, rather than STP-mediated diffusion, is rate limiting in the cellular context, so there is no apparent kinetic benefit to having STP-mediated sterol transfer occur at contact sites. Contact sites may instead compartmentalize lipid synthesis or transport machinery, providing opportunities for regulation.", "title": "Speed Limits for Nonvesicular Intracellular Sterol Transport." } ]

[ { "docid": "9669099", "text": "Binding within or nearby target genes involved in cell proliferation and survival enables the p53 tumor suppressor gene to regulate their transcription and cell-cycle progression. Using genome-wide chromatin-binding profiles, we describe binding of p53 also to regions located distantly from any known p53 target gene. Interestingly, many of these regions possess conserved p53-binding sites and all known hallmarks of enhancer regions. We demonstrate that these p53-bound enhancer regions (p53BERs) indeed contain enhancer activity and interact intrachromosomally with multiple neighboring genes to convey long-distance p53-dependent transcription regulation. Furthermore, p53BERs produce, in a p53-dependent manner, enhancer RNAs (eRNAs) that are required for efficient transcriptional enhancement of interacting target genes and induction of a p53-dependent cell-cycle arrest. Thus, our results ascribe transcription enhancement activity to p53 with the capacity to regulate multiple genes from a single genomic binding site. Moreover, eRNA production from p53BERs is required for efficient p53 transcription enhancement.", "title": "eRNAs are required for p53-dependent enhancer activity and gene transcription." } ]

[ { "docid": "43880096", "text": "Activation of p53 can occur in response to a number of cellular stresses, including DNA damage, hypoxia and nucleotide deprivation. Several forms of DNA damage have been shown to activate p53, including those generated by ionising radiation (IR), radio-mimetic drugs, ultraviolet light (UV) and chemicals such as methyl methane sulfonate (MMS). Under normal conditions, p53 levels are maintained at a low state by virtue of the extremely short-half life of the polypeptide. In addition to this, p53 normally exists in an largely inactive state that is relatively inefficient at binding to DNA and activating transcription. Activation of p53 in response to DNA damage is associated with a rapid increase in its levels and with an increased ability of p53 to bind DNA and mediate transcriptional activation. This then leads to the activation of a number of genes whose products trigger cell-cycle arrest, apoptosis, or DNA repair. Recent work has suggested that this regulation is brought about largely through DNA damage triggering a series of phosphorylation, de-phosphorylation and acetylation events on the p53 polypeptide. Here, we discuss the nature of these modifications, the enzymes that bring them about, and how changes in p53 modification lead to p53 activation.", "title": "Regulation of p53 in response to DNA damage" }, { "docid": "21557055", "text": "The tumor suppressor protein, p53, plays a critical role in mediating cellular response to stress signals by regulating genes involved in cell cycle arrest and apoptosis. p53 is believed to be inactive for DNA binding unless its C terminus is modified or structurally altered. We show that unmodified p53 actively binds to two sites at -1.4 and -2.3 kb within the chromatin-assembled p21 promoter and requires the C terminus and the histone acetyltransferase, p300, for transcription. Acetylation of the C terminus by p300 is not necessary for binding or promoter activation. Instead, p300 acetylates p53-bound nucleosomes in the p21 promoter with spreading to the TATA box. Thus, p53 is an active DNA and chromatin binding protein that may selectively regulate its target genes by recruitment of specific cofactors to structurally distinct binding sites.", "title": "Transcriptional regulation by p53 through intrinsic DNA/chromatin binding and site-directed cofactor recruitment." }, { "docid": "37204802", "text": "Jumonji domain-containing 6 (JMJD6) is a member of the Jumonji C domain-containing family of proteins. Compared to other members of the family, the cellular activity of JMJD6 is still not clearly defined and its biological function is still largely unexplored. Here we report that JMJD6 is physically associated with the tumor suppressor p53. We demonstrated that JMJD6 acts as an α-ketoglutarate- and Fe(II)-dependent lysyl hydroxylase to catalyze p53 hydroxylation. We found that p53 indeed exists as a hydroxylated protein in vivo and that the hydroxylation occurs mainly on lysine 382 of p53. We showed that JMJD6 antagonizes p53 acetylation, promotes the association of p53 with its negative regulator MDMX, and represses transcriptional activity of p53. Depletion of JMJD6 enhances p53 transcriptional activity, arrests cells in the G1 phase, promotes cell apoptosis, and sensitizes cells to DNA damaging agent-induced cell death. Importantly, knockdown of JMJD6 represses p53-dependent colon cell proliferation and tumorigenesis in vivo, and significantly, the expression of JMJD6 is markedly up-regulated in various types of human cancer especially in colon cancer, and high nuclear JMJD6 protein is strongly correlated with aggressive clinical behaviors of colon adenocarcinomas. Our results reveal a novel posttranslational modification for p53 and support the pursuit of JMJD6 as a potential biomarker for colon cancer aggressiveness and a potential target for colon cancer intervention.", "title": "JMJD6 Promotes Colon Carcinogenesis through Negative Regulation of p53 by Hydroxylation" }, { "docid": "6896063", "text": "p53 functions as a transcription factor involved in cell-cycle control, DNA repair, apoptosis and cellular stress responses. However, besides inducing cell growth arrest and apoptosis, p53 activation also modulates cellular senescence and organismal aging. Senescence is an irreversible cell-cycle arrest that has a crucial role both in aging and as a robust physiological antitumor response, which counteracts oncogenic insults. Therefore, via the regulation of senescence, p53 contributes to tumor growth suppression, in a manner strictly dependent by its expression and cellular context. In this review, we focus on the recent advances on the contribution of p53 to cellular senescence and its implication for cancer therapy, and we will discuss p53’s impact on animal lifespan. Moreover, we describe p53-mediated regulation of several physiological pathways that could mediate its role in both senescence and aging.", "title": "Senescence and aging: the critical roles of p53" }, { "docid": "7225911", "text": "It is well known that upon stress, the level of the tumor suppressor p53 is remarkably elevated. However, despite extensive studies, the underlying mechanism involving important inter-players for stress-induced p53 regulation is still not fully understood. We present evidence that the human lincRNA-RoR (RoR) is a strong negative regulator of p53. Unlike MDM2 that causes p53 degradation through the ubiquitin-proteasome pathway, RoR suppresses p53 translation through direct interaction with the heterogeneous nuclear ribonucleoprotein I (hnRNP I). Importantly, a 28-base RoR sequence carrying hnRNP I binding motifs is essential and sufficient for p53 repression. We further show that RoR inhibits p53-mediated cell cycle arrest and apoptosis. Finally, we demonstrate a RoR-p53 autoregulatory feedback loop where p53 transcriptionally induces RoR expression. Together, these results suggest that the RoR-hnRNP I-p53 axis may constitute an additional surveillance network for the cell to better respond to various stresses.", "title": "The human long non-coding RNA-RoR is a p53 repressor in response to DNA damage" }, { "docid": "25901598", "text": "Posttranslational modifications mediate important regulatory functions in biology. The acetylation of the p53 transcription factor, for example, promotes transcriptional activation of target genes including p21. Here we show that the acetylation of two lysine residues in p53 promotes recruitment of the TFIID subunit TAF1 to the p21 promoter through its bromodomains. UV irradiation of cells diacetylates p53 at lysines 373 and 382, which in turn recruits TAF1 to a distal p53-binding site on the p21 promoter prior to looping to the core promoter. Disruption of acetyl-p53/bromodomain interaction inhibits TAF1 recruitment to both the distal p53-binding site and the core promoter. Further, the TFIID subunits TAF4, TAF5, and TBP are detected on the core promoter prior to TAF1, suggesting that, upon DNA damage, distinct subunits of TFIID may be recruited separately to the p21 promoter and that the transcriptional activation depends on posttranslational modification of the p53 transcription factor.", "title": "An acetylation switch in p53 mediates holo-TFIID recruitment." }, { "docid": "9169645", "text": "The ability of p53 to induce apoptosis requires its sequence-specific DNA binding activity; however, the transactivation-deficient p53(Gln22-Ser23) can still induce apoptosis. Previously, we have shown that the region between residues 23 and 97 in p53 is necessary for such activity. In an effort to more precisely map a domain necessary for apoptosis within the N terminus, we found that deletion of the N-terminal 23 amino acids compromises, but does not abolish, p53 induction of apoptosis. Surprisingly, p53(Delta1-42), which lacks the N-terminal 42 amino acids and the previously defined activation domain, retains the ability to induce apoptosis to an even higher level than wild-type p53. A more extensive deletion, which eliminates the N-terminal 63 amino acids, renders p53 completely inert in mediating apoptosis. In addition, we found that both p53(Delta1-42) and p53(Gln22-Ser23) can activate a subset of cellular p53 targets. Furthermore, we showed that residues 53 and 54 are critical for the apoptotic and transcriptional activities of both p53(Delta1-42) and p53(Gln22-Ser23). Taken together, these data suggest that within residues 43-63 lie an apoptotic domain as well as another transcriptional activation domain. We therefore postulate that the apoptotic activity in p53(Gln22-Ser23) and p53(Delta1-42) is still transcription-dependent.", "title": "Identification of a novel p53 functional domain that is necessary for mediating apoptosis." }, { "docid": "23985464", "text": "Wild-type p53 has recently been shown to repress transcription from several cellular and viral promoters. Since p53 mutations are the most frequently reported genetic defects in human cancers, it becomes important to study the effects of mutations of p53 on promoter functions. We, therefore, have studied the effects of wild-type and mutant human p53 on the human proliferating-cell nuclear antigen (PCNA) promoter and on several viral promoters, including the herpes simplex virus type 1 UL9 promoter, the human cytomegalovirus major immediate-early promoter-enhancer, and the long terminal repeat promoters of Rous sarcoma virus and human T-cell lymphotropic virus type I. HeLa cells were cotransfected with a wild-type or mutant p53 expression vector and a plasmid containing a chloramphenicol acetyltransferase reporter gene under viral (or cellular) promoter control. As expected, expression of the wild-type p53 inhibited promoter function. Expression of a p53 with a mutation at any one of the four amino acid positions 175, 248, 273, or 281, however, correlated with a significant increase of the PCNA promoter activity (2- to 11-fold). The viral promoters were also activated, although to a somewhat lesser extent. We also showed that activation by a mutant p53 requires a minimal promoter containing a lone TATA box. A more significant increase (25-fold) in activation occurs when the promoter contains a binding site for the activating transcription factor or cyclic AMP response element-binding protein. Using Saos-2 cells that do not express p53, we showed that activation by a mutant p53 was a direct enhancement. The mutant forms of p53 used in this study are found in various cancer cells. The activation of PCNA by mutant p53s may indicate a way to increase cell proliferation by the mutant p53s. Thus, our data indicate a possible functional role for the mutants of p53 found in cancer cells in activating several important loci, including PCNA.", "title": "Modulation of cellular and viral promoters by mutant human p53 proteins found in tumor cells." }, { "docid": "36464673", "text": "We show that, in vitro, Ca2+-dependent protein kinase C (PKC) phosphorylates recombinant murine p53 protein on several residues contained within a conserved basic region of 25 amino acids, located in the C-terminal part of the protein. Accordingly, synthetic p53-(357-381)-peptide is phosphorylated by PKC at multiple Ser and Thr residues, including Ser360, Thr365, Ser370 and Thr377. We also establish that p53-(357-381)-peptide at micromolar concentrations has the ability to stimulate sequence-specific DNA binding by p53. That stimulation is lost upon phosphorylation by PKC. To further characterise the mechanisms that regulate PKC-dependent phosphorylation of p53-(357-381)-peptide, the phosphorylation of recombinant p53 and p53-(357-381)-peptide by PKC were compared. The results suggest that phosphorylation of full-length p53 on the C-terminal PKC sites is highly dependent on the accessibility of the phosphorylation sites and that a domain on p53 distinct from p53-(357-381)-peptide is involved in binding PKC. Accordingly, we have identified a conserved 27-amino-acid peptide, p53-(320-346)-peptide, within the C-terminal region of p53 and adjacent to residues 357-381 that interacts with PKC in vitro. The interaction between p53-(320-346)-peptide and PKC inhibits PKC autophosphorylation and the phosphorylation of substrates, including p53-(357-381)-peptide, neurogranin and histone H1. Conventional Ca2+-dependent PKC alpha, beta and gamma and the catalytic fragment of PKC (PKM) were nearly equally susceptible to inhibition by p53-(320-346)-peptide. The Ca2+-independent PKC delta was much less sensitive to inhibition. The significance of these findings for understanding the in vivo phosphorylation of p53 by PKC are discussed.", "title": "The in vitro phosphorylation of p53 by calcium-dependent protein kinase C--characterization of a protein-kinase-C-binding site on p53." }, { "docid": "2582169", "text": "The importance of coordinating cell growth with proliferation has been recognized for a long time. The molecular basis of this relationship, however, is poorly understood. Here we show that the ribosomal protein L23 interacts with HDM2. The interaction involves the central acidic domain of HDM2 and an N-terminal domain of L23. L23 and L11, another HDM2-interacting ribosomal protein, can simultaneously yet distinctly interact with HDM2 together to form a ternary complex. We show that, when overexpressed, L23 inhibits HDM2-induced p53 polyubiquitination and degradation and causes a p53-dependent cell cycle arrest. On the other hand, knocking down L23 causes nucleolar stress and triggers translocation of B23 from the nucleolus to the nucleoplasm, leading to stabilization and activation of p53. Our data suggest that cells may maintain a steady-state level of L23 during normal growth; alternating the levels of L23 in response to changing growth conditions could impinge on the HDM2-p53 pathway by interrupting the integrity of the nucleolus.", "title": "Inhibition of HDM2 and activation of p53 by ribosomal protein L23." }, { "docid": "42489926", "text": "p53 regulates a key pathway which protects normal tissues from tumor development that may result from diverse forms of stress. In the absence of stress, growth suppressive and proapoptotic activity of p53 is inhibited by MDM2 which binds p53 and negatively regulates its activity and stability. MDM2 antagonists could activate p53 and may offer a novel therapeutic approach to cancer. Recently, we identified the first potent and selective low molecular weight inhibitors of MDM2-p53 binding, the Nutlins. These molecules activate the p53 pathway and suppress tumor growth in vitro and in vivo. They represent valuable new tools for studying the p53 pathway and its defects in cancer. Nutlins induce p53-dependent apoptosis in human cancer cells but appear cytostatic to proliferating normal cells. Their potent activity against osteosarcoma xenografts suggests that MDM2 antagonists may have clinical utility in the treatment of tumors with wild-type p53.", "title": "Small-molecule antagonists of p53-MDM2 binding: research tools and potential therapeutics." }, { "docid": "9483851", "text": "p53 is a crucial tumour suppressor that responds to diverse stress signals by orchestrating specific cellular responses, including transient cell cycle arrest, cellular senescence and apoptosis, which are all processes associated with tumour suppression. However, recent studies have challenged the relative importance of these canonical cellular responses for p53-mediated tumour suppression and have highlighted roles for p53 in modulating other cellular processes, including metabolism, stem cell maintenance, invasion and metastasis, as well as communication within the tumour microenvironment. In this Opinion article, we discuss the roles of classical p53 functions, as well as emerging p53-regulated processes, in tumour suppression.", "title": "Unravelling mechanisms of p53-mediated tumour suppression" }, { "docid": "11903247", "text": "Multiple cellular stressors, including activation of the tumour suppressor p53, can stimulate autophagy. Here we show that deletion, depletion or inhibition of p53 can induce autophagy in human, mouse and nematode cells subjected to knockout, knockdown or pharmacological inhibition of p53. Enhanced autophagy improved the survival of p53-deficient cancer cells under conditions of hypoxia and nutrient depletion, allowing them to maintain high ATP levels. Inhibition of p53 led to autophagy in enucleated cells, and cytoplasmic, not nuclear, p53 was able to repress the enhanced autophagy of p53−/− cells. Many different inducers of autophagy (for example, starvation, rapamycin and toxins affecting the endoplasmic reticulum) stimulated proteasome-mediated degradation of p53 through a pathway relying on the E3 ubiquitin ligase HDM2. Inhibition of p53 degradation prevented the activation of autophagy in several cell lines, in response to several distinct stimuli. These results provide evidence of a key signalling pathway that links autophagy to the cancer-associated dysregulation of p53.", "title": "Regulation of autophagy by cytoplasmic p53" }, { "docid": "24721866", "text": "Macrophage-derived foam cells play important roles in the progression of atherosclerosis. We reported previously that ERK1/2-dependent granulocyte/macrophage colony-stimulating factor (GM-CSF) expression, leading to p38 MAPK/ Akt signaling, is important for oxidized low density lipoprotein (Ox-LDL)-induced macrophage proliferation. Here, we investigated whether activation of AMP-activated protein kinase (AMPK) could suppress macrophage proliferation. Ox-LDL-induced proliferation of mouse peritoneal macrophages was assessed by [(3)H]thymidine incorporation and cell counting assays. The proliferation was significantly inhibited by the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) and restored by dominant-negative AMPKalpha1, suggesting that AMPK activation suppressed macrophage proliferation. AICAR partially suppressed Ox-LDL-induced ERK1/2 phosphorylation and GM-CSF expression, suggesting that another mechanism is also involved in the AICAR-mediated suppression of macrophage proliferation. AICAR suppressed GM-CSF-induced macrophage proliferation without suppressing p38 MAPK/Akt signaling. GM-CSF suppressed p53 phosphorylation and expression and induced Rb phosphorylation. Overexpression of p53 or p27(kip) suppressed GM-CSF-induced macrophage proliferation. AICAR induced cell cycle arrest, increased p53 phosphorylation and expression, and suppressed GM-CSF-induced Rb phosphorylation via AMPK activation. Moreover, AICAR induced p21(cip) and p27(kip) expression via AMPK activation, and small interfering RNA (siRNA) of p21(cip) and p27(kip) restored AICAR-mediated suppression of macrophage proliferation. In conclusion, AMPK activation suppressed Ox-LDL-induced macrophage proliferation by suppressing GM-CSF expression and inducing cell cycle arrest. These effects of AMPK activation may represent therapeutic targets for atherosclerosis.", "title": "Activation of AMP-activated protein kinase suppresses oxidized low-density lipoprotein-induced macrophage proliferation." }, { "docid": "47018050", "text": "Here, we report that genome editing by CRISPR–Cas9 induces a p53-mediated DNA damage response and cell cycle arrest in immortalized human retinal pigment epithelial cells, leading to a selection against cells with a functional p53 pathway. Inhibition of p53 prevents the damage response and increases the rate of homologous recombination from a donor template. These results suggest that p53 inhibition may improve the efficiency of genome editing of untransformed cells and that p53 function should be monitored when developing cell-based therapies utilizing CRISPR–Cas9. CRISPR–Cas9-induced DNA damage triggers p53 to limit the efficiency of gene editing in immortalized human retinal pigment epithelial cells.", "title": "CRISPR–Cas9 genome editing induces a p53-mediated DNA damage response" }, { "docid": "10015292", "text": "Highly regenerative tissues such as blood must possess effective DNA damage responses (DDR) that balance long-term regeneration with protection from leukemogenesis. Hematopoietic stem cells (HSCs) sustain life-long blood production, yet their response to DNA damage remains largely unexplored. We report that human HSCs exhibit delayed DNA double-strand break rejoining, persistent gammaH2AX foci, and enhanced p53- and ASPP1-dependent apoptosis after gamma-radiation compared to progenitors. p53 inactivation or Bcl-2 overexpression reduced radiation-induced apoptosis and preserved in vivo repopulating HSC function. Despite similar protection from irradiation-induced apoptosis, only Bcl-2-overexpressing HSCs showed higher self-renewal capacity, establishing that intact p53 positively regulates self-renewal independently from apoptosis. The reduced self-renewal of HSCs with inactivated p53 was associated with increased spontaneous gammaH2AX foci in secondary transplants of HSCs. Our data reveal distinct physiological roles of p53 that together ensure optimal HSC function: apoptosis regulation and prevention of gammaH2AX foci accumulation upon HSC self-renewal.", "title": "A distinctive DNA damage response in human hematopoietic stem cells reveals an apoptosis-independent role for p53 in self-renewal." }, { "docid": "14460402", "text": "The molecular mechanisms that regulate adult neural precursor cell (NPC) survival, and thus maintain adult neurogenesis, are not well defined. Here, we investigate the role of p63, a p53 family member, in adult NPC function in mice. Conditional ablation of p63 in adult NPCs or p63 haploinsufficiency led to reduced numbers of NPCs and newborn neurons in the neurogenic zones of the hippocampus and lateral ventricles and in the olfactory bulb. These reductions were attributable to enhanced apoptosis of NPCs and newborn neurons and were rescued by inhibition of caspase activity, p53, or the p53 apoptotic effector PUMA (p53-upregulated modulator of apoptosis). Moreover, these cellular deficits were functionally important because they led to perturbations in hippocampus-dependent memory formation. These results indicate that p63 regulates the numbers of adult NPCs and adult-born neurons as well as neural stem cell-dependent cognitive functions, and that it does so, at least in part, by inhibiting p53-dependent cell death.", "title": "p63 Regulates adult neural precursor and newly born neuron survival to control hippocampal-dependent Behavior." }, { "docid": "7465900", "text": "BACKGROUND & AIMS Helicobacter pylori-induced gastric epithelial cell (GEC) apoptosis is a complex process that includes activation of the tumor suppressor p53. p53-mediated apoptosis involves p53 activation, bax transcription, and cytochrome c release from mitochondria. Apurinic/apyrimidinic endonuclease-1 (APE-1) regulates transcriptional activity of p53, and H pylori induce APE-1 expression in human GECs. H pylori infection increases intracellular calcium ion concentration [Ca2+]i of GECs, which induces APE-1 acetylation. We investigated the effects of H pylori infection and APE-1 acetylation on GEC apoptosis. \n METHODS AGS cells (wild-type or with suppressed APE-1), KATO III cells, and cells isolated from gastric biopsy specimens were infected with H pylori. Effects were examined by immunoblotting, real-time reverse-transcription polymerase chain reaction, immunoprecipitation, immunofluorescence microscopy, chromatin immunoprecipitation, mobility shift, DNA binding, and luciferase assays. \n RESULTS H pylori infection increased [Ca2+]i and acetylation of APE-1 in GECs, but the acetylation status of APE-1 did not affect the transcriptional activity of p53. In GECs, expression of a form of APE-1 that could not be acetylated increased total and mitochondrial levels of Bax and induced release of cytochrome c and fragmentation of DNA; expression of wild-type APE-1 reduced these apoptotic events. We identified a negative calcium response element in the human bax promoter and found that poly (adenosine diphosphate-ribose) polymerase 1 recruited the acetylated APE-1/histone deacetylase-1 repressor complex to bax nCaRE. \n CONCLUSIONS H pylori-mediated acetylation of APE-1 suppresses Bax expression; this prevents p53-mediated apoptosis when H pylori infect GECs.", "title": "Acetylation of apurinic/apyrimidinic endonuclease-1 regulates Helicobacter pylori-mediated gastric epithelial cell apoptosis." }, { "docid": "4389394", "text": "The p53 tumour suppressor is a short-lived protein that is maintained at low levels in normal cells by Mdm2-mediated ubiquitination and subsequent proteolysis. Stabilization of p53 is crucial for its tumour suppressor function. However, the precise mechanism by which ubiquitinated p53 levels are regulated in vivo is not completely understood. By mass spectrometry of affinity-purified p53-associated factors, we have identified herpesvirus-associated ubiquitin-specific protease (HAUSP) as a novel p53-interacting protein. HAUSP strongly stabilizes p53 even in the presence of excess Mdm2, and also induces p53-dependent cell growth repression and apoptosis. Significantly, HAUSP has an intrinsic enzymatic activity that specifically deubiquitinates p53 both in vitro and in vivo. In contrast, expression of a catalytically inactive point mutant of HAUSP in cells increases the levels of p53 ubiquitination and destabilizes p53. These findings reveal an important mechanism by which p53 can be stabilized by direct deubiquitination and also imply that HAUSP might function as a tumour suppressor in vivo through the stabilization of p53.", "title": "Deubiquitination of p53 by HAUSP is an important pathway for p53 stabilization" } ]

[ { "docid": "16322674", "text": "BACKGROUND Birth size, perhaps a proxy for prenatal environment, might be a correlate of subsequent breast cancer risk, but findings from epidemiological studies have been inconsistent. We re-analysed individual participant data from published and unpublished studies to obtain more precise estimates of the magnitude and shape of the birth size-breast cancer association. \n METHODS AND FINDINGS Studies were identified through computer-assisted and manual searches, and personal communication with investigators. Individual participant data from 32 studies, comprising 22,058 breast cancer cases, were obtained. Random effect models were used, if appropriate, to combine study-specific estimates of effect. Birth weight was positively associated with breast cancer risk in studies based on birth records (pooled relative risk [RR] per one standard deviation [SD] [= 0.5 kg] increment in birth weight: 1.06; 95% confidence interval [CI] 1.02-1.09) and parental recall when the participants were children (1.02; 95% CI 0.99-1.05), but not in those based on adult self-reports, or maternal recall during the woman's adulthood (0.98; 95% CI 0.95-1.01) (p for heterogeneity between data sources = 0.003). Relative to women who weighed 3.000-3.499 kg, the risk was 0.96 (CI 0.80-1.16) in those who weighed < 2.500 kg, and 1.12 (95% CI 1.00-1.25) in those who weighed > or = 4.000 kg (p for linear trend = 0.001) in birth record data. Birth length and head circumference from birth records were also positively associated with breast cancer risk (pooled RR per one SD increment: 1.06 [95% CI 1.03-1.10] and 1.09 [95% CI 1.03-1.15], respectively). Simultaneous adjustment for these three birth size variables showed that length was the strongest independent predictor of risk. The birth size effects did not appear to be confounded or mediated by established breast cancer risk factors and were not modified by age or menopausal status. The cumulative incidence of breast cancer per 100 women by age 80 y in the study populations was estimated to be 10.0, 10.0, 10.4, and 11.5 in those who were, respectively, in the bottom, second, third, and top fourths of the birth length distribution. \n CONCLUSIONS This pooled analysis of individual participant data is consistent with birth size, and in particular birth length, being an independent correlate of breast cancer risk in adulthood.", "title": "Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies" }, { "docid": "27123743", "text": "Breast cancer may originate in utero. We reviewed the available evidence on the association between birthweight and the risk of breast cancer. To date, 26 research papers addressing this issue have been published. The majority of studies identified a positive link between birthweight and premenopausal, but not postmenopausal, breast cancer. The relative risk estimate for breast cancer comparing women with high birthweight to women with low birthweight combining all studies including both pre- and postmenopausal breast cancer was 1.23 (95% confidence interval 1.13-1.34). The mechanisms underlying this association likely include elevated levels of growth factors that may increase the number of susceptible stem cells in the mammary gland or initiate tumors through DNA mutations. Loss of imprinting (LOI) of growth hormone genes relevant for intrauterine growth, such as insulin-like growth factor 2 (IGF2), leads to abnormally high levels of these hormones evidenced by high birthweight. LOI of IGF2 has also been found in mammary tumor tissue. The role of environmental factors that stimulate such epigenetic regulation of gene expression remains to be elucidated.", "title": "Role of birthweight in the etiology of breast cancer." }, { "docid": "23557241", "text": "BACKGROUND Emerging evidence suggests an association between female prenatal experience and her subsequent risk of developing breast cancer. Potential underlying mechanisms include variation in amounts of maternal endogenous sex hormones and growth hormones, germ-cell mutations, formation of cancer stem-cells, and other genetic or epigenetic events. We reviewed and summarised quantitatively the available data on intrauterine exposures and risk of breast cancer. \n METHODS We systematically searched for studies that assessed association between perinatal factors and risk of breast cancer. We reviewed separately each of the perinatal factors, including birthweight, birth length, parental age at delivery, gestational age, intrauterine exposure to diethylstilbestrol, twin membership, maternal pre-eclampsia or eclampsia, and other factors. \n FINDINGS We identified 57 studies published between Oct 1, 1980, and June 21, 2007. Increased risk of breast cancer was noted with increased birthweight (relative risk [RR] 1.15 [95% CI 1.09-1.21]), birth length (1.28 [1.11-1.48]), higher maternal age (1.13 [1.02-1.25]), and paternal age (1.12 [1.05-1.19]). Decreased risk of breast cancer was noted for maternal pre-eclampsia and eclampsia (0.48 [0.30-0.78]) and twin membership (0.93 [0.87-1.00]). No association was noted between risk of breast cancer and gestational age at birth (0.95 [0.71-1.26]) or maternal diethylstilbestrol treatment (1.40 [0.86-2.28]). \n INTERPRETATION The intrauterine environment contributes to the predisposition of women to breast cancer in adulthood. The in-utero mechanisms responsible for such predisposition need to be elucidated.", "title": "Intrauterine factors and risk of breast cancer: a systematic review and meta-analysis of current evidence." }, { "docid": "17450673", "text": "INTRODUCTION Various perinatal factors, including birth weight, birth order, maternal age, gestational age, twin status, and parental smoking, have been postulated to affect breast cancer risk in daughters by altering the hormonal environment of the developing fetal mammary glands. Despite ample biologic plausibility, epidemiologic studies to date have yielded conflicting results. We investigated the associations between perinatal factors and subsequent breast cancer risk through meta-analyses. \n METHODS We reviewed breast cancer studies published from January 1966 to February 2007 that included data on birth weight, birth order, maternal age, gestational age, twin status, and maternal or paternal smoking. Meta-analyses using random effect models were employed to summarize the results. \n RESULTS We found that heavier birth weights were associated with increased breast cancer risk, with studies involving five categories of birth weight identifying odds ratios (ORs) of 1.24 (95% confidence interval [CI] 1.04 to 1.48) for 4,000 g or more and 1.15 (95% CI 1.04 to 1.26) for 3,500 g to 3,999 g, relative to a birth weight of 2,500 to 2,599 g. These studies provided no support for a J-shaped relationship of birthweight to risk. Support for an association with birthweight was also derived from studies based on three birth weight categories (OR 1.15 [95% CI 1.01 to 1.31] for > or =4,000 g relative to <3,000 g) and two birth weight categories (OR 1.09 [95% CI 1.02 to 1.18] for > or =3,000 g relative to <3,000 g). Women born to older mothers and twins were also at some increased risk, but the results were heterogeneous across studies and publication years. Birth order, prematurity, and maternal smoking were unrelated to breast cancer risk. \n CONCLUSION Our findings provide some support for the hypothesis that in utero exposures reflective of higher endogenous hormone levels could affect risk for development of breast cancer in adulthood.", "title": "Intrauterine environments and breast cancer risk: meta-analysis and systematic review" } ]

[ { "docid": "37480103", "text": "CONTEXT During pregnancy, serum levels of estrogen, progesterone, and other hormones are markedly higher than during other periods of life. Pregnancy hormones primarily are produced in the placenta, and signs of placental impairment may serve as indirect markers of hormone exposures during pregnancy. During pregnancy, these markers have been inconsistently associated with subsequent risk of breast cancer in the mother. \n OBJECTIVE To examine associations between indirect markers of hormonal exposures, such as placental weight and other pregnancy characteristics, and maternal risk of developing breast cancer. \n DESIGN AND SETTING Population-based cohort study using data from the Swedish Birth Register, the Swedish Cancer Register, the Swedish Cause of Death Register, and the Swedish Register of Population and Population Changes. \n PARTICIPANTS Women included in the Sweden Birth Register who delivered singletons between 1982 and 1989, with complete information on date of birth and gestational age. Women were followed up until the occurrence of breast cancer, death, or end of follow-up (December 31, 2001). Cox proportional hazards models were used to estimate associations between hormone exposures and risks of breast cancer. \n MAIN OUTCOME MEASURE Incidence of invasive breast cancer. \n RESULTS Of 314,019 women in the cohort, 2216 (0.7%) developed breast cancer during the follow-up through 2001, of whom 2100 (95%) were diagnosed before age 50 years. Compared with women who had placentas weighing less than 500 g in 2 consecutive pregnancies, the risk of breast cancer was increased among women whose placentas weighed between 500 and 699 g in their first pregnancy and at least 700 g in their second pregnancy (or vice versa) (adjusted hazard ratio, 1.82; 95% confidence interval [CI], 1.07-3.08), and the corresponding risk was doubled among women whose placentas weighed at least 700 g in both pregnancies (adjusted hazard ratio, 2.05; 95% CI, 1.15-3.64). A high birth weight (> or =4000 g) in 2 successive births was associated with an increased risk of breast cancer before but not after adjusting for placental weight and other covariates (adjusted hazard ratio, 1.10; 95% CI, 0.76-1.59). \n CONCLUSIONS Placental weight is positively associated with maternal risk of breast cancer. These results further support the hypothesis that pregnancy hormones are important modifiers of subsequent maternal breast cancer risk.", "title": "Pregnancy characteristics and maternal risk of breast cancer." }, { "docid": "5487448", "text": "Birth weight is a significant predictor of breast cancer risk in adult life and mammary gland mass could be an intermediate stage in this long process. We have studied the association of birth size measurements with mammographic density, a marker of mammary gland mass. For a population-based sample of 893 postmenopausal women without previous cancer in Sweden, we retrieved information on birth size from birth records and their most recent mammography. Film mammograms of the medio-lateral oblique view were digitized and the Cumulus software was used for computer-assisted semi-automated thresholding of mammographic density. Results were analyzed using generalized linear models controlling for possible confounders. Mean percent mammographic density increased when comparing the extreme categories of birth weight (from 15.6% to 18.6%) and head circumference (from 15.5% to 20.4%), and the corresponding linear trends were statistically significant (p values 0.02 and 0.007, respectively). The associations were particularly strong when the cutoff for high versus low mammographic density was set at the relatively high value of 50%. Compared to women weighing 3001-3500 grams at birth, women with birth weights >4000g were at almost 3-fold risk of developing high mammographic density (odds ratio: 2.9, 95% confidence interval 1.1 to 7.9). No association with mammographic density was evident with respect to birth length which, however, is known to be less accurately measured. These results indicate that adult breast density, a powerful predictor of breast cancer risk, has intrauterine roots, as reflected in birth size.", "title": "Birth weight and mammographic density among postmenopausal women in Sweden." }, { "docid": "38784540", "text": "Objective To determine whether risk factors in childhood and early adulthood affect later mammographic breast density. Methods: Subjects were 628 women who attended a medical examination at the University of Glasgow Student Health Service (1948–1968), responded to a questionnaire (2001) and had a screening mammogram in Scotland (1989–2002). Mammograms (median age of 59years) were classified using a six category classification (SCC) of breast density percent. Logistic regression was used to determine associations between risk factors and having a high-risk mammogram (≥25 dense). Results: In multi-variable analyses, high-risk mammograms were associated with parity (adjusted odds ratio (OR) per child: 0.77 (95 confidence interval (CI) 0.61–0.99)), age at first birth, OR per year: 1.05 (0.99–1.11), smoking at university, OR smokers versus non-smokers: 0.58 (0.36–0.92) and body mass index (BMI) while at university, OR per 1kg/m20.75 (0.69–0.82). No associations with SCC were found for age at menarche, birth weight, oral contraceptive (OC) use, height, leg length or exercise at age 20. Conclusions: We confirm previous findings that breast density is affected by reproductive events and some anthropometric measures, however most of the risk factors acting throughout the life course which we examined were not closely related to adult breast density.", "title": "Life course breast cancer risk factors and adult breast density (United Kingdom)" }, { "docid": "22007333", "text": "Menstrual and reproductive factors may increase breast cancer risk through a pathway that includes increased mammographic density. We assessed whether known or suspected menstrual and reproductive breast cancer risk factors were cross-sectionally associated with mammographic density, by measuring area of radiographic density and total breast area on mammograms from 801 participants in the Study of Women’s Health Across the Nation (SWAN), a multi-ethnic cohort of pre- and early perimenopausal women. From multivariable linear regression, the following menstrual or reproductive factors were independently associated with percent mammographic density (area of dense breast/breast area): older age at menarche (β = 10.3, P < 0.01, for >13 vs. <12 years), premenstrual cravings and bloating (β = −3.36, P = 0.02), younger age at first full-term birth (β = −8.12, P < 0.01 for ≤23 years versus no births), greater number of births (β = −6.80, P < 0.01 for ≥3 births versus no births), and premenopausal status (β = 3.78, P < 0.01 versus early perimenopausal). Only number of births remained associated with percent density after adjustment for age, race/ethnicity, study site, body mass index (BMI), and smoking. In addition, stratified analyses revealed that the association with number of births was confined to women within the lowest BMI tertile (β = −12.2, P < 0.01 for ≥3 births versus no births). Our data support a mechanism for parity and breast cancer that involves mammographic density among pre- and early perimenopausal women that may be modified by body size.", "title": "Menstrual and reproductive factors in relation to mammographic density: the Study of Women’s Health Across the Nation (SWAN)" }, { "docid": "13765757", "text": "Ages at menarche and first birth are established risk factors for breast cancer. The interval between these ages may also affect risk, since the breast is more susceptible to carcinogenic insults during this period than during the parous period. However, few investigators have studied this relation. Using logistic regression, the authors evaluated associations between the timing of reproductive events and breast cancer risk among 4,013 cases and 4,069 controls enrolled in a multicenter, population-based US case-control study of White and African-American women (1994-1998). For White, parous premenopausal and postmenopausal women, those who had an interval of > or =16 years between the ages of menarche and first birth had 1.5-fold (95% confidence interval (CI): 1.0, 2.2) and 1.4-fold (95% CI: 1.1, 1.8) increased risks of breast cancer, respectively, in comparison with those who had < or =5 years between these ages. Adjusting for age at first birth altered these risk estimates somewhat, to odds ratios of 1.5 (95% CI: 0.8, 2.9) and 1.0 (95% CI: 0.6, 1.5), respectively. These associations were stronger for lobular and hormone-receptor-positive tumors but were absent among premenopausal African-American women. The authors conclude that the interval between age at menarche and age at first birth is associated with the risk of hormonally sensitive types of breast cancer, particularly among White women.", "title": "Timing of menarche and first full-term birth in relation to breast cancer risk." }, { "docid": "16098747", "text": "Evaluate known breast cancer risk factors in relation to breast density. We examined factors in relation to breast density in 144,018 New Hampshire (NH) women with at least one mammogram recorded in a statewide mammography registry. Mammographic breast density was measured by radiologists using the BI-RADS classification; risk factors of interest were obtained from patient intake forms and questionnaires. Initial analyses showed a strong inverse influence of age and body mass index (BMI) on breast density. In addition, women with late age at menarche, late age at first birth, premenopausal women, and those currently using hormone therapy (HT) tended to have higher breast density, while those with greater parity tended to have less dense breasts. Analyses stratified on age and BMI suggested interactions, which were formally assessed in a multivariable model. The impact of current HT use, relative to nonuse, differed across age groups, with an inverse association in younger women, and a positive association in older women (p < 0.0001 for the interaction). The positive effects of age at menarche and age at first birth, and the inverse influence of parity were less apparent in women with low BMI than in those with high BMI (p = 0.04, p < 0.0001 and p = 0.01, respectively, for the interactions). We also noted stronger positive effects for age at first birth in postmenopausal women (p = 0.004 for the interaction). The multivariable model indicated a slight positive influence of family history of breast cancer. The influence of age at menarche and reproductive factors on breast density is less evident in women with high BMI. Density is reduced in young women using HT, but increased in HT users of age 50 or more.", "title": "Breast cancer risk factors in relation to breast density (United States)" }, { "docid": "13831842", "text": "The association between anthropometric indices and the risk of breast cancer was analyzed using pooled data from seven prospective cohort studies. Together, these cohorts comprise 337,819 women and 4,385 incident invasive breast cancer cases. In multivariate analyses controlling for reproductive, dietary, and other risk factors, the pooled relative risk (RR) of breast cancer per height increment of 5 cm was 1.02 (95% confidence interval (CI): 0.96, 1.10) in premenopausal women and 1.07 (95% CI: 1.03, 1.12) in postmenopausal women. Body mass index (BMI) showed significant inverse and positive associations with breast cancer among pre- and postmenopausal women, respectively; these associations were nonlinear. Compared with premenopausal women with a BMI of less than 21 kg/m2, women with a BMI exceeding 31 kg/m2 had an RR of 0.54 (95% CI: 0.34, 0.85). In postmenopausal women, the RRs did not increase further when BMI exceeded 28 kg/m2; the RR for these women was 1.26 (95% CI: 1.09, 1.46). The authors found little evidence for interaction with other breast cancer risk factors. Their data indicate that height is an independent risk factor for postmenopausal breast cancer; in premenopausal women, this relation is less clear. The association between BMI and breast cancer varies by menopausal status. Weight control may reduce the risk among postmenopausal women.", "title": "Pooled analysis of prospective cohort studies on height, weight, and breast cancer risk." }, { "docid": "3285322", "text": "PURPOSE Mutations in the BRCA1 and BRCA2 genes confer greater risk of developing breast cancer. We determined whether tumor pathologic features and clinical features differ in patients with and without BRCA mutations. \n PATIENTS AND METHODS Tumor pathologic features and clinical characteristics were examined in 491 women with breast cancer who underwent genetic testing for BRCA mutations between 1997 and 2006. A retrospective review of medical records was conducted to determine clinical characteristics including ethnicity, age and clinical stage at diagnosis, age at parity, number of full-term pregnancies, use of oral contraceptives and hormone replacement therapy, and BRCA mutation status. Tumor pathology was reviewed to determine histologic type, tumor grade, and estrogen receptor, progesterone receptor, and HER-2/neu status. \n RESULTS Of the 491 patients with identified breast cancers, 391 patients were BRCA negative, and 86 patients were BRCA positive. Triple-negative breast cancer (ie, those with negative estrogen receptor, progesterone receptor, and HER-2/neu status) was diagnosed in 57.1% of the BRCA1-positive patients, 23.3% of the BRCA2-positive patients, and 13.8% of the BRCA-negative patients. BRCA1 mutation carriers had higher nuclear grade tumors than the other two groups (P < .001). Of the triple-negative cancer patients, BRCA2 mutation carriers were older when diagnosed than BRCA1 mutation carriers and noncarriers (P < .01). \n CONCLUSION These results suggest that tumors associated with BRCA1 mutations may be divided into two distinct groups, triple-negative and non-triple-negative groups. Future studies should seek to determine whether patients with BRCA1 mutations and triple-negative breast cancer respond to treatment better than BRCA-negative patients with similar tumor pathology.", "title": "Clinical and pathologic characteristics of patients with BRCA-positive and BRCA-negative breast cancer." }, { "docid": "13831558", "text": "BACKGROUND Extensive mammographic density is associated with an increased risk of breast cancer and makes the detection of cancer by mammography difficult, but the influence of density on risk according to method of cancer detection is unknown. \n METHODS We carried out three nested case-control studies in screened populations with 1112 matched case-control pairs. We examined the association of the measured percentage of density in the baseline mammogram with risk of breast cancer, according to method of cancer detection, time since the initiation of screening, and age. \n RESULTS As compared with women with density in less than 10% of the mammogram, women with density in 75% or more had an increased risk of breast cancer (odds ratio, 4.7; 95% confidence interval [CI], 3.0 to 7.4), whether detected by screening (odds ratio, 3.5; 95% CI, 2.0 to 6.2) or less than 12 months after a negative screening examination (odds ratio, 17.8; 95% CI, 4.8 to 65.9). Increased risk of breast cancer, whether detected by screening or other means, persisted for at least 8 years after study entry and was greater in younger than in older women. For women younger than the median age of 56 years, 26% of all breast cancers and 50% of cancers detected less than 12 months after a negative screening test were attributable to density in 50% or more of the mammogram. \n CONCLUSIONS Extensive mammographic density is strongly associated with the risk of breast cancer detected by screening or between screening tests. A substantial fraction of breast cancers can be attributed to this risk factor.", "title": "Mammographic density and the risk and detection of breast cancer." }, { "docid": "313403", "text": "The tumor microenvironment is composed of tumor cells, fibroblasts, endothelial cells and infiltrating immune cells, which may inhibit or promote tumor growth and progression. The objectives of this retrospective study were to characterize the density of tumor-associated macrophages (TAMs) in breast cancer, and to correlate the density of TAMs with clinicopathological parameters. Paraffin-embedded specimens and clinicopathological data, including up to 5 years follow-up information, were obtained from 172 breast cancer patients. Immunohistochemical staining for CD68 (marker for macrophages) was performed and evaluated in a blinded fashion. We found that TAMs were significantly frequent in high histopathological grade breast cancer patients. Breast cancer patients with a high density of TAMs had significantly lower rates of disease-free survival and 5-year overall survival than patients with low density of TAMs. Furthermore, high-infiltration of TAMs indicated worse survival rate for patients with node-negative breast cancer. In conclusion, the number of TAMs in the tumor stroma is an independent predictor of survival time for breast cancer patients. High-infiltration of TAMs is a significant unfavorable prognostic factor for patients with invasive breast cancer and, as such, is a potentially useful prognostic marker for breast cancer.", "title": "High-Infiltration of Tumor-Associated Macrophages Predicts Unfavorable Clinical Outcome for Node-Negative Breast Cancer" }, { "docid": "25973484", "text": "Obesity has a complicated relationship to both breast cancer risk and the clinical behavior of the established disease. In postmenopausal women, particularly the elderly, various measures of obesity have been positively associated with risk. However, before menopause increased body weight is inversely related to breast cancer risk. In both premenopausal and postmenopausal breast cancer, the mechanisms by which body weight and obesity affect risk have been related to estrogenic activity. Obesity has also been related to advanced disease at diagnosis and with a poor prognosis in both premenopausal and postmenopausal breast cancer. Breast cancer in African-American women, considering its relationship to obesity, exhibits some important differences from those described in white women, although the high prevalence of obesity in African-American women may contribute to the relatively poor prognosis compared with white American women. Despite the emphasis on estrogens to explain the effects of obesity on breast cancer, other factors may prove to be equally or more important, particularly as they relate to expression of an aggressive tumor phenotype. Among these, this review serves to stress insulin, insulin-like growth factor-I, and leptin, and their relationship to angiogenesis, and transcriptional factors.", "title": "Breast cancer and obesity: an update." }, { "docid": "1171121", "text": "A considerable subgroup of patients with early breast cancer does not address benefits of anthracycline based chemotherapy. The aim of this retrospective study was to investigate the effect of microvessel density (MVD) and status of p53 protein on 5-year disease free survival (DFS) in the group of breast cancer patients treated with anthracyclines in adjuvant setting. Correlations between MVD, p53 status and other clinicopathological parameters were also assessed. MVD and p53 status were analyzed immunohistochemically in the group of 172 women with breast cancer in clinical stage T1-2, N1-N2, M0. There were 123 tumors (71.5 %) with lower MVD (≤ 214.8 microvesells/mm(2)) and 49 (28.5 %) with higher MVD (>214.8 microvesells/mm(2)). The proportion of higher MVD tumors significantly increased in N2 (P = 0.000) and in estrogen (P = 0.046) or progesterone receptors (P = 0.029) negative tumors. p53 positivity was indicated in 50 cancers (29.1 %) and was significantly associated with higher grade (P = 0.000), steroid receptors negativity (P = 0.000), cytokeratin5/6 positivity (P = 0.026), topoisomerase IIα overexpression (P = 0.005) and higher proliferation rate (P = 0.001). In univariate analysis, higher MVD (P = 0.016) and p53 negativity (P = 0.023) were significantly related with longer DFS (median follow-up 36 months). In multivariate Cox regression analysis MVD was independently associated with DFS. These data suggest that higher MVD is favourable prognostic factors for early advanced breast cancer patients after adjuvant anthracycline based chemotherapy.", "title": "Microvessel Density and Status of p53 Protein as Potential Prognostic Factors for Adjuvant Anthracycline Chemotherapy in Retrospective Analysis of Early Breast Cancer Patients Group" }, { "docid": "20280410", "text": "Inherited mutations in the gene BRCA2 predispose carriers to early onset breast cancer, but such mutations account for fewer than 2% of all cases in East Anglia. It is likely that low penetrance alleles explain the greater part of inherited susceptibility to breast cancer; polymorphic variants in strongly predisposing genes, such as BRCA2, are candidates for this role. BRCA2 is thought to be involved in DNA double strand break-repair. Few mice in which Brca2 is truncated survive to birth; of those that do, most are male, smaller than their normal littermates and have high cancer incidence. Here we show that a common human polymorphism (N372H) in exon 10 of BRCA2 confers an increased risk of breast cancer: the HH homozygotes have a 1.31-fold (95% CI, 1.07–1.61) greater risk than the NN group. Moreover, in normal female controls of all ages there is a significant deficiency of homozygotes compared with that expected from Hardy-Weinberg equilibrium, whereas in males there is an excess of homozygotes: the HH group has an estimated fitness of 0.82 in females and 1.38 in males. Therefore, this variant of BRCA2 appears also to affect fetal survival in a sex-dependent manner.", "title": "A common variant in BRCA2 is associated with both breast cancer risk and prenatal viability" }, { "docid": "5222182", "text": "Understanding which factors influence mammographically dense and nondense areas is important because percent mammographic density adjusted for age is a strong, continuously distributed risk factor for breast cancer, especially when adjusted for weight or body mass index. Using computer-assisted methods, we measured mammographically dense areas for 571 monozygotic and 380 dizygotic Australian and North American twin pairs ages 40 to 70 years. We used a novel regression modeling approach in which each twin's measure of dense and nondense area was regressed against one or both of the twin's and co-twin's covariates. The nature of changes to regression estimates with the inclusion of the twin and/or co-twin's covariates can be evaluated for consistency with causal and/or other models. By causal, we mean that if it were possible to vary a covariate experimentally then the expected value of the outcome measure would change. After adjusting for the individual's weight, the co-twin associations with weight were attenuated, consistent with a causal effect of weight on mammographic measures, which in absolute log cm(2)/kg was thrice stronger for nondense than dense area. After adjusting for weight, later age at menarche, and greater height were associated with greater dense and lesser nondense areas in a manner inconsistent with causality. The associations of dense and nondense areas with parity are consistent with a causal effect and/or within-person confounding. The associations between mammographic density measures and height are consistent with shared early life environmental factors that predispose to both height and percent mammographic density and possibly breast cancer risk.", "title": "Predictors of mammographic density: insights gained from a novel regression analysis of a twin study." }, { "docid": "16701509", "text": "BACKGROUND The prevalence of metabolic syndrome (obesity, glucose intolerance, low serum high-density lipoprotein cholesterol [HDL-C], high serum triglycerides, hypertension) is high and increasing in parallel with an increasing breast cancer incidence worldwide. HDL-C represents an important aspect of the syndrome, yet its role in breast cancer is still undefined. \n METHODS In two population-based screening surveys during 1977-1983 and 1985-1987, serum HDL-C was assayed enzymatically among 38,823 Norwegian women aged 17-54 years at entry. Height, weight, blood pressure, serum lipids, fat and energy intake, physical activity, parity, oral contraceptive use, hormone therapy use, alcohol intake, and tobacco use were also assessed. We used Cox proportional hazards modeling to estimate the relative risk (RR) of breast cancer associated with serum HDL-C levels and to adjust for potential confounding variables. We performed stratified analyses to evaluate effect modification by body mass index (BMI) and menopausal status. All statistical tests were two-sided. \n RESULTS During a median follow-up of 17.2 years, we identified 708 cases of invasive breast cancer. In multivariable analysis, the risk of postmenopausal breast cancer was inversely related to quartile of HDL-C (P(trend) =.02). Among women with HDL-C above 1.64 mmol/L (highest quartile) versus below 1.20 mmol/L (lowest quartile), the relative risk was 0.75 (95% confidence interval [CI] = 0.58 to 0.97). The HDL-C association was confined to women in the heavier subgroup (BMI > or =25 kg/m2), for whom the relative risk of postmenopausal breast cancer in those with HDL-C above 1.64 mmol/L versus below 1.20 mmol/L was 0.43 (95% CI = 0.28 to 0.67; P(trend)<.001; P(interaction) =.001). \n CONCLUSION Low HDL-C, as part of the metabolic syndrome, is associated with increased postmenopausal breast cancer risk.", "title": "Serum high-density lipoprotein cholesterol, metabolic profile, and breast cancer risk." }, { "docid": "18340282", "text": "BACKGROUND Information is scarce about the combined effects on breast cancer incidence of low-penetrance genetic susceptibility polymorphisms and environmental factors (reproductive, behavioural, and anthropometric risk factors for breast cancer). To test for evidence of gene-environment interactions, we compared genotypic relative risks for breast cancer across the other risk factors in a large UK prospective study. \n METHODS We tested gene-environment interactions in 7610 women who developed breast cancer and 10 196 controls without the disease, studying the effects of 12 polymorphisms (FGFR2-rs2981582, TNRC9-rs3803662, 2q35-rs13387042, MAP3K1-rs889312, 8q24-rs13281615, 2p-rs4666451, 5p12-rs981782, CASP8-rs1045485, LSP1-rs3817198, 5q-rs30099, TGFB1-rs1982073, and ATM-rs1800054) in relation to prospectively collected information about ten established environmental risk factors (age at menarche, parity, age at first birth, breastfeeding, menopausal status, age at menopause, use of hormone replacement therapy, body-mass index, height, and alcohol consumption). \n FINDINGS After allowance for multiple testing none of the 120 comparisons yielded significant evidence of a gene-environment interaction. By contrast with previous suggestions, there was little evidence that the genotypic relative risks were affected by use of hormone replacement therapy, either overall or for oestrogen-receptor-positive disease. Only one of the 12 polymorphisms was correlated with any of the ten other risk factors: carriers of the high-risk C allele of MAP3K1-rs889312 were significantly shorter than non-carriers (mean height 162.4 cm [95% CI 162.1-162.7] vs 163.1 cm [162.9-163.2]; p=0.01 after allowance for multiple testing). \n INTERPRETATION Risks of breast cancer associated with low-penetrance susceptibility polymorphisms do not vary significantly with these ten established environmental risk factors. \n FUNDING Cancer Research UK and the UK Medical Research Council.", "title": "Gene–environment interactions in 7610 women with breast cancer: prospective evidence from the Million Women Study" }, { "docid": "27240667", "text": "PURPOSE Since 1990, overall breast cancer mortality rates in the United States decreased 24%. This decline has been attributed to mammography screening and adjuvant systemic therapy. However, the efficacy of these modalities may depend on estrogen receptor (ER) expression and age. We therefore examined breast cancer mortality trends in the United States according to ER status and age. \n METHODS Using the Surveillance, Epidemiology, and End Results (SEER) program (1990-2003), we calculated trends in incidence-based mortality (IBM), annual hazard rates for breast cancer deaths after diagnosis, and relative hazard rates for women with ER-positive and ER-negative tumors. Relative hazard rates were assessed with Cox proportional hazards models, adjusted for stage and grade, and stratified by age at diagnosis. \n RESULTS During the study period, IBM and annual hazard rates for breast cancer deaths decreased among women with ER-positive and ER-negative tumors, although declines were greater for those with ER-positive tumors. Among women younger than 70 years, relative hazard rates declined 38% for those with ER-positive tumors versus 19% for those with ER-negative tumors. Among women 70 years or older, relative hazard rates declined 14% for those with ER-positive tumors versus no significant decline for those with ER-negative tumors. \n CONCLUSION In the United States, breast cancer mortality rates have declined among women with ER-positive and ER-negative tumors, with greater declines among younger women and those with ER-positive tumors. Although mortality in all groups remains unacceptably high, additional emphasis should be placed on improving outcomes of breast cancer patients older than 70 years and those of all ages with ER-negative tumors.", "title": "Breast cancer mortality trends in the United States according to estrogen receptor status and age at diagnosis." } ]

[ { "docid": "16966326", "text": "Genetic mutations in TAR DNA-binding protein 43 (TARDBP, also known as TDP-43) cause amyotrophic lateral sclerosis (ALS), and an increase in the presence of TDP-43 (encoded by TARDBP) in the cytoplasm is a prominent histopathological feature of degenerating neurons in various neurodegenerative diseases. However, the molecular mechanisms by which TDP-43 contributes to ALS pathophysiology remain elusive. Here we have found that TDP-43 accumulates in the mitochondria of neurons in subjects with ALS or frontotemporal dementia (FTD). Disease-associated mutations increase TDP-43 mitochondrial localization. In mitochondria, wild-type (WT) and mutant TDP-43 preferentially bind mitochondria-transcribed messenger RNAs (mRNAs) encoding respiratory complex I subunits ND3 and ND6, impair their expression and specifically cause complex I disassembly. The suppression of TDP-43 mitochondrial localization abolishes WT and mutant TDP-43-induced mitochondrial dysfunction and neuronal loss, and improves phenotypes of transgenic mutant TDP-43 mice. Thus, our studies link TDP-43 toxicity directly to mitochondrial bioenergetics and propose the targeting of TDP-43 mitochondrial localization as a promising therapeutic approach for neurodegeneration.", "title": "The Inhibition of TDP-43 Mitochondrial Localization Blocks Its Neuronal Toxicity" } ]

[ { "docid": "9217800", "text": "The fatal adult motor neuron disease amyotrophic lateral sclerosis (ALS) shares some clinical and pathological overlap with frontotemporal dementia (FTD), an early-onset neurodegenerative disorder. The RNA/DNA-binding proteins fused in sarcoma (FUS; also known as TLS) and TAR DNA binding protein-43 (TDP-43) have recently been shown to be genetically and pathologically associated with familial forms of ALS and FTD. It is currently unknown whether perturbation of these proteins results in disease through mechanisms that are independent of normal protein function or via the pathophysiological disruption of molecular processes in which they are both critical. Here, we report that Drosophila mutants in which the homolog of FUS is disrupted exhibit decreased adult viability, diminished locomotor speed, and reduced life span compared with controls. These phenotypes were fully rescued by wild-type human FUS, but not ALS-associated mutant FUS proteins. A mutant of the Drosophila homolog of TDP-43 had similar, but more severe, deficits. Through cross-rescue analysis, we demonstrated that FUS acted together with and downstream of TDP-43 in a common genetic pathway in neurons. Furthermore, we found that these proteins associated with each other in an RNA-dependent complex. Our results establish that FUS and TDP-43 function together in vivo and suggest that molecular pathways requiring the combined activities of both of these proteins may be disrupted in ALS and FTD.", "title": "The ALS-associated proteins FUS and TDP-43 function together to affect Drosophila locomotion and life span." }, { "docid": "13717103", "text": "INTRODUCTION Mutations in the FUS gene have been shown to be a rare cause of amyotrophic lateral sclerosis (ALS-FUS) and whilst well documented clinically and genetically there have been relatively few neuropathological studies. Recent work suggested a possible correlation between pathological features such as frequency of basophilic inclusions in neurons and rate of clinical decline, other studies have revealed a discrepancy between the upper motor neuron features detected clinically and the associated pathology. The purpose of this study was to describe the pathological features associated with more recently discovered FUS mutations and reinvestigate those with well recognised mutations in an attempt to correlate the pathology with mutation and/or clinical phenotype. The brains and spinal cords of seven cases of ALS-FUS were examined neuropathologically, including cases with the newly described p. K510E mutation and a case with both a known p. P525L mutation in the FUS gene and a truncating p. Y374X mutation in the TARDBP gene. \n RESULTS The neuropathology in all cases revealed basophilic and FUS inclusions in the cord. The density and type of inclusions varied markedly between cases, but did not allow a clear correlation with clinical progression. Only one case showed significant motor cortical pathology despite the upper motor neuron clinical features being evident in 4 patients. The case with both a FUS and TARDBP mutation revealed FUS positive inclusions but no TDP-43 pathology. Instead there were unusual p62 positive, FUS negative neuronal and glial inclusions as well as dot-like neurites. \n CONCLUSIONS The study confirms cases of ALS-FUS to be mainly a lower motor neuron disease and to have pathology that does not appear to neatly correlate with clinical features or genetics. Furthermore, the case with both a FUS and TARDBP mutation reveals an intriguing pathological profile which at least in part involves a very unusual staining pattern for the ubiquitin-binding protein p62.", "title": "ALS-FUS pathology revisited: singleton FUS mutations and an unusual case with both a FUS and TARDBP mutation" }, { "docid": "14893425", "text": "The loss of a glutamic acid residue in the AAA-ATPase (ATPases associated with diverse cellular activities) torsinA is responsible for most cases of early onset autosomal dominant primary dystonia. In this study, we found that snapin, which binds SNAP-25 (synaptosome-associated protein of 25,000 Da) and enhances the association of the SNARE complex with synaptotagmin, is an interacting partner for both wild type and mutant torsinA. Snapin co-localized with endogenous torsinA on dense core granules in PC12 cells and was recruited to perinuclear inclusions containing mutant DeltaE-torsinA in neuroblastoma SH-SY5Y cells. In view of these observations, synaptic vesicle recycling was analyzed using the lipophilic dye FM1-43 and an antibody directed against an intravesicular epitope of synaptotagmin I. We found that overexpression of wild type torsinA negatively affects synaptic vesicle endocytosis. Conversely, overexpression of DeltaE-torsinA in neuroblastoma cells increases FM1-43 uptake. Knockdown of snapin and/or torsinA using small interfering RNAs had a similar inhibitory effect on the exo-endocytic process. In addition, down-regulation of torsinA causes the persistence of synaptotagmin I on the plasma membrane, which closely resembles the effect observed by the overexpression of the DeltaE-torsinA mutant. Altogether, these findings suggest that torsinA plays a role together with snapin in regulated exocytosis and that DeltaE-torsinA exerts its pathological effects through a loss of function mechanism. This may affect neuronal uptake of neurotransmitters, such as dopamine, playing a role in the development of dystonic movements.", "title": "The dystonia-associated protein torsinA modulates synaptic vesicle recycling." }, { "docid": "13380011", "text": "Partial inhibition of mitochondrial respiratory complex I by rotenone reproduces aspects of Parkinson's disease in rodents. The hypothesis that rotenone enhancement of neuronal cell death is attributable to oxidative stress was tested in an acute glutamate excitotoxicity model using primary cultures of rat cerebellar granule neurons. As little as 5 nM rotenone increased mitochondrial superoxide (O2*-) levels and potentiated glutamate-induced cytoplasmic Ca2+ deregulation, the first irreversible stage of necrotic cell death. However, the potent cell-permeant O2*- trap manganese tetrakis (N-ethylpyridinium-2yl) porphyrin failed to prevent the effects of the inhibitor. The bioenergetic consequences of rotenone addition were quantified by monitoring cell respiration. Glutamate activation of NMDA receptors used the full respiratory capacity of the in situ mitochondria, and >80% of the glutamate-stimulated respiration was attributable to increased cellular ATP demand. Rotenone at 20 nM inhibited basal and carbonyl cyanide p-trifluoromethoxyphenylhydrazone-stimulated cell respiration and caused respiratory failure in the presence of glutamate. ATP synthase inhibition by oligomycin was also toxic in the presence of glutamate. We conclude that the cell vulnerability in the rotenone model of partial complex I deficiency under these specific conditions is primarily determined by spare respiratory capacity rather than oxidative stress.", "title": "Spare respiratory capacity rather than oxidative stress regulates glutamate excitotoxicity after partial respiratory inhibition of mitochondrial complex I with rotenone." }, { "docid": "12149169", "text": "Synthesis of ribosomal RNA (rRNA) by RNA polymerase (Pol) I is the first step in ribosome biogenesis and a regulatory switch in eukaryotic cell growth. Here we report the 12 A cryo-electron microscopic structure for the complete 14-subunit yeast Pol I, a homology model for the core enzyme, and the crystal structure of the subcomplex A14/43. In the resulting hybrid structure of Pol I, A14/43, the clamp, and the dock domain contribute to a unique surface interacting with promoter-specific initiation factors. The Pol I-specific subunits A49 and A34.5 form a heterodimer near the enzyme funnel that acts as a built-in elongation factor and is related to the Pol II-associated factor TFIIF. In contrast to Pol II, Pol I has a strong intrinsic 3'-RNA cleavage activity, which requires the C-terminal domain of subunit A12.2 and, apparently, enables ribosomal RNA proofreading and 3'-end trimming.", "title": "Functional Architecture of RNA Polymerase I" }, { "docid": "4928057", "text": "Organ-specific functions of tissue-resident macrophages in the steady-state heart are unknown. Here, we show that cardiac macrophages facilitate electrical conduction through the distal atrioventricular node, where conducting cells densely intersperse with elongated macrophages expressing connexin 43. When coupled to spontaneously beating cardiomyocytes via connexin-43-containing gap junctions, cardiac macrophages have a negative resting membrane potential and depolarize in synchrony with cardiomyocytes. Conversely, macrophages render the resting membrane potential of cardiomyocytes more positive and, according to computational modeling, accelerate their repolarization. Photostimulation of channelrhodopsin-2-expressing macrophages improves atrioventricular conduction, whereas conditional deletion of connexin 43 in macrophages and congenital lack of macrophages delay atrioventricular conduction. In the Cd11bDTR mouse, macrophage ablation induces progressive atrioventricular block. These observations implicate macrophages in normal and aberrant cardiac conduction.", "title": "Macrophages Facilitate Electrical Conduction in the Heart" }, { "docid": "13448422", "text": "This review discusses some of the mechanisms inherent in diabetes that predispose patients to increased cardiac morbidity and mortality. Single photon emission computerized tomography or photon emission tomography with radioactive labeled analogues of norepinephrine have shown that cardiac sympathetic dysfunction and incompetence are early and also late abnormalities in patients with Type I (insulin-dependent) and Type II (non-insulin-dependent) diabetes mellitus. Furthermore, myocardial blood flow assessment with photon emission tomography has shown that in patients without myocardial perfusion deficits, endothelial-dependent vasodilatation is severely reduced in relation to cardiac sympathetic dysfunction. In addition, signs of endothelial activation have also been found early in patients with Type I and Type II diabetes in whom vascular disease has not been clinically detected. This activation in conjunction with glycaemic control is important in determining macrovascular mortality. Cardiac sympathetic dysfunction is partially restored to normal with near normalisation of glycaemia. Interpretations. Recently unrecognized “subtle” changes predispose the heart to failure, after ischaemia-induced remodelling, and arteriosclerotic plaques to instability and rupture. These changes act in conjunction with effects, driven by hyperglycaemia and diabetes, on the endothelium of large blood vessels, e. g. on nitric oxide release or on protein kinase-C β activation. Meticulous glucose control early on and rapid recompensation of hyperglycaemia in patients with acute coronary syndrome are part of a successful intensive multifactorial approach to prevent the heart in diabetes converting from ailing to failing. [Diabetologia (2000) 43: 1455–1469]", "title": "A new look at the heart in diabetes mellitus: from ailing to failing" }, { "docid": "22938539", "text": "A comprehensive mapping of interactions among Epstein-Barr virus (EBV) proteins and interactions of EBV proteins with human proteins should provide specific hypotheses and a broad perspective on EBV strategies for replication and persistence. Interactions of EBV proteins with each other and with human proteins were assessed by using a stringent high-throughput yeast two-hybrid system. Overall, 43 interactions between EBV proteins and 173 interactions between EBV and human proteins were identified. EBV-EBV and EBV-human protein interaction, or \"interactome\" maps provided a framework for hypotheses of protein function. For example, LF2, an EBV protein of unknown function interacted with the EBV immediate early R transactivator (Rta) and was found to inhibit Rta transactivation. From a broader perspective, EBV genes can be divided into two evolutionary classes, \"core\" genes, which are conserved across all herpesviruses and subfamily specific, or \"noncore\" genes. Our EBV-EBV interactome map is enriched for interactions among proteins in the same evolutionary class. Furthermore, human proteins targeted by EBV proteins were enriched for highly connected or \"hub\" proteins and for proteins with relatively short paths to all other proteins in the human interactome network. Targeting of hubs might be an efficient mechanism for EBV reorganization of cellular processes.", "title": "Epstein-Barr virus and virus human protein interaction maps." }, { "docid": "1275505", "text": "Little is known about the molecular basis of somatosensory mechanotransduction in mammals. We screened a library of peptide toxins for effects on mechanically activated currents in cultured dorsal root ganglion neurons. One conopeptide analogue, termed NMB-1 for noxious mechanosensation blocker 1, selectively inhibits (IC50 1 µM) sustained mechanically activated currents in a subset of sensory neurons. Biotinylated NMB-1 retains activity and binds selectively to peripherin-positive nociceptive sensory neurons. The selectivity of NMB-1 was confirmed by the fact that it has no inhibitory effects on voltage-gated sodium and calcium channels, or ligand-gated channels such as acid-sensing ion channels or TRPA1 channels. Conversely, the tarantula toxin, GsMTx-4, which inhibits stretch-activated ion channels, had no effects on mechanically activated currents in sensory neurons. In behavioral assays, NMB-1 inhibits responses only to high intensity, painful mechanical stimulation and has no effects on low intensity mechanical stimulation or thermosensation. Unexpectedly, NMB-1 was found to also be an inhibitor of rapid FM1-43 loading (a measure of mechanotransduction) in cochlear hair cells. These data demonstrate that pharmacologically distinct channels respond to distinct types of mechanical stimuli and suggest that mechanically activated sustained currents underlie noxious mechanosensation. NMB-1 thus provides a novel diagnostic tool for the molecular definition of channels involved in hearing and pressure-evoked pain.", "title": "High-Threshold Mechanosensitive Ion Channels Blocked by a Novel Conopeptide Mediate Pressure-Evoked Pain" }, { "docid": "2543135", "text": "Autophagy plays a central role in regulating important cellular functions such as cell survival during starvation and control of infectious pathogens. Recently, it has been shown that autophagy can induce cells to die; however, the mechanism of the autophagic cell death program is unclear. We now show that caspase inhibition leading to cell death by means of autophagy involves reactive oxygen species (ROS) accumulation, membrane lipid oxidation, and loss of plasma membrane integrity. Inhibition of autophagy by chemical compounds or knocking down the expression of key autophagy proteins such as ATG7, ATG8, and receptor interacting protein (RIP) blocks ROS accumulation and cell death. The cause of abnormal ROS accumulation is the selective autophagic degradation of the major enzymatic ROS scavenger, catalase. Caspase inhibition directly induces catalase degradation and ROS accumulation, which can be blocked by autophagy inhibitors. These findings unveil a molecular mechanism for the role of autophagy in cell death and provide insight into the complex relationship between ROS and nonapoptotic programmed cell death.", "title": "Autophagic programmed cell death by selective catalase degradation." }, { "docid": "665817", "text": "AIMS Frontotemporal lobar degeneration (FTLD) is clinically and pathologically heterogeneous. Although associated with variations in MAPT, GRN and C9ORF72, the pathogenesis of these, and of other nongenetic, forms of FTLD, remains unknown. Epigenetic factors such as histone regulation by histone deacetylases (HDAC) may play a role in the dysregulation of transcriptional activity, thought to underpin the neurodegenerative process. \n METHODS The distribution and intensity of HDACs 4, 5 and 6 was assessed semi-quantitatively in immunostained sections of temporal cortex with hippocampus, and cerebellum, from 33 pathologically confirmed cases of FTLD and 27 controls. \n RESULTS We found a significantly greater intensity of cytoplasmic immunostaining for HDAC4 and HDAC6 in granule cells of the dentate gyrus in cases of FTLD overall compared with controls, and specifically in cases of FTLD tau-Picks compared with FTLD tau-MAPT and controls. No differences were noted between FTLD-TDP subtypes, or between the different genetic and nongenetic forms of FTLD. No changes were seen in HDAC5 in any FTLD or control cases. \n CONCLUSIONS Dysregulation of HDAC4 and/or HDAC6 could play a role in the pathogenesis of FTLD-tau associated with Pick bodies, although their lack of immunostaining implies that such changes do not contribute directly to the formation of Pick bodies.", "title": "Histone deacetylases (HDACs) in frontotemporal lobar degeneration." }, { "docid": "4889228", "text": "Aberrant alternative splicing has been highlighted as a potential hallmark of cancer. Here, we identify TDP43 (TAR DNA-binding protein 43) as an important splicing regulator responsible for the unique splicing profile in triple-negative breast cancer (TNBC). Clinical data demonstrate that TDP43 is highly expressed in TNBC with poor prognosis. Knockdown of TDP43 inhibits tumor progression, including proliferation and metastasis, and overexpression of TDP43 promotes proliferation and malignancy of mammary epithelial cells. Deep sequencing analysis and functional experiments indicate that TDP43 alters most splicing events with splicing factor SRSF3 (serine/arginine-rich splicing factor 3), in the regulation of TNBC progression. The TDP43/SRSF3 complex controls specific splicing events, including downstream genes PAR3 and NUMB The effect of reduced metastasis and proliferation upon the knockdown of TDP43 or SRSF3 is mediated by the splicing regulation of PAR3 and NUMB exon 12, respectively. The TDP43/SRSF3 complex and downstream PAR3 isoform are potential therapeutic targets for TNBC.", "title": "Loss of TDP43 inhibits progression of triple-negative breast cancer in coordination with SRSF3" }, { "docid": "23403754", "text": "In this review I summarize interrelations between bioenergetic processes and such programmed death phenomena as cell suicide (apoptosis and necrosis) and mitochondrial suicide (mitoptosis). The following conclusions are made. (I) ATP and rather often mitochondrial hyperpolarization (i.e. an increase in membrane potential, ΔΨ) are required for certain steps of apoptosis and necrosis. (II) Apoptosis, even if it is accompanied by ΔΨ and [ATP] increases at its early stage, finally results in a ΔΨ collapse and ATP decrease. (III) Moderate (about three-fold) lowering of [ATP] for short and long periods of time induces apoptosis and necrosis, respectively. In some types of apoptosis and necrosis, the cell death is mediated by a ΔΨ-dependent overproduction of ROS by the initial (Complex I) and the middle (Complex III) spans of the respiratory chain. ROS initiate mitoptosis which is postulated to rid the intracellular population of mitochondria from those that are ROS overproducing. Massive mitoptosis can result in cell death due to release to cytosol of the cell death proteins normally hidden in the mitochondrial intermembrane space.", "title": "Bioenergetic aspects of apoptosis, necrosis and mitoptosis" }, { "docid": "26596106", "text": "In the yeast S. cerevisiae, ribosome assembly is linked to environmental conditions by the coordinate transcriptional regulation of genes required for ribosome biogenesis. In this study we show that two nonessential stress-responsive genes, YAR1 and LTV1, function in 40S subunit production. We provide genetic and biochemical evidence that Yar1, a small ankyrin-repeat protein, physically interacts with RpS3, a component of the 40S subunit, and with Ltv1, a protein recently identified as a substoichiometric component of a 43S preribosomal particle. We demonstrate that cells lacking YAR1 or LTV1 are hypersensitive to particular protein synthesis inhibitors and exhibit aberrant polysome profiles, with a reduced absolute number of 40S subunits and an excess of free 60S subunits. Surprisingly, both mutants are also hypersensitive to a variety of environmental stress conditions. Overexpression of RPS3 suppresses both the stress sensitivity and the ribosome biogenesis defect of Deltayar1 mutants, but does not suppress either defect in Deltaltv1 mutants. We propose that YAR1 and LTV1 play distinct, nonessential roles in 40S subunit production. The stress-sensitive phenotypes of strains lacking these genes reveal a hitherto unknown link between ribosome biogenesis factors and environmental stress sensitivity.", "title": "Genetic and biochemical interactions among Yar1, Ltv1 and Rps3 define novel links between environmental stress and ribosome biogenesis in Saccharomyces cerevisiae." }, { "docid": "44366096", "text": "Double-stranded RNA (dsRNA) produced during viral replication is believed to be the critical trigger for activation of antiviral immunity mediated by the RNA helicase enzymes retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5). We showed that influenza A virus infection does not generate dsRNA and that RIG-I is activated by viral genomic single-stranded RNA (ssRNA) bearing 5'-phosphates. This is blocked by the influenza protein nonstructured protein 1 (NS1), which is found in a complex with RIG-I in infected cells. These results identify RIG-I as a ssRNA sensor and potential target of viral immune evasion and suggest that its ability to sense 5'-phosphorylated RNA evolved in the innate immune system as a means of discriminating between self and nonself.", "title": "RIG-I-mediated antiviral responses to single-stranded RNA bearing 5'-phosphates." }, { "docid": "11840194", "text": "Conventional protocols for differentiating human induced-pluripotent stem cells (hiPSCs) into smooth-muscle cells (SMCs) can be inefficient and generally fail to yield cells with a specific SMC phenotype (i.e., contractile or synthetic SMCs). Here, we present two novel hiPSC-SMC differentiation protocols that yield SMCs with predominantly contractile or synthetic phenotypes. Flow cytometry analyses of smooth-muscle actin (SMA) expression indicated that ~45% of the cells obtained with each protocol assumed an SMC phenotype, and that the populations could be purified to ~95% via metabolic selection. Assessments of cellular mRNA and/or protein levels indicated that SMA, myosin heavy chain II, collagen 1, calponin, transgelin, connexin 43, and vimentin expression in the SMCs obtained via the Contractile SMC protocol and in SMCs differentiated via a traditional protocol were similar, while SMCs produced via the Sythetic SMC protocol expressed less calponin, more collagen 1, and more connexin 43. Differences were also observed in functional assessments of the two SMC populations: the two-dimensional surface area of Contractile SMCs declined more extensively (to 12% versus 44% of original size) in response to carbachol treatment, while quantification of cell migration and proliferation were greater in Synthetic SMCs. Collectively, these data demonstrate that our novel differentiation protocols can efficiently generate SMCs from hiPSCs.", "title": "Differentiation of Human Induced-Pluripotent Stem Cells into Smooth-Muscle Cells: Two Novel Protocols" }, { "docid": "17168045", "text": "BACKGROUND This study sought to describe and quantify microcirculatory changes in the mucosal surfaces of patients with severe malaria, by direct in vivo observation using orthogonal polarization spectral (OPS) imaging. \n METHODS The microcirculation in the rectal mucosa of adult patients with severe malaria was assessed by use of OPS imaging, at admission and then daily. Comparison groups comprised patients with uncomplicated falciparum malaria, patients with bacterial sepsis, and healthy individuals. \n RESULTS Erythrocyte velocities were measured directly in 43 adult patients with severe falciparum malaria, of whom 20 died. Microcirculatory blood flow was markedly disturbed, with heterogeneous obstruction that was proportional to severity of disease. Blocked capillaries were found in 29 patients (67%) and were associated with concurrent hyperdynamic blood flow (erythrocyte velocity, >750 mm/s) in adjacent vessels in 27 patients (93%). The proportion of blocked capillaries correlated with the base deficit in plasma and with the concentration of lactate. Abnormalities disappeared when the patients recovered. In healthy individuals and in patients with uncomplicated malaria or sepsis, no stagnant erythrocytes were detected, and, in patients with sepsis, hyperdynamic blood flow was prominent. \n CONCLUSION Patients with severe falciparum malaria show extensive microvascular obstruction that is proportional to the severity of the disease. This finding underscores the prominent role that microvascular obstruction plays in the pathophysiology of severe malaria and illustrates the fundamental difference between the microvascular pathophysiology of malaria and that of bacterial sepsis.", "title": "Direct in vivo assessment of microcirculatory dysfunction in severe falciparum malaria." }, { "docid": "6722522", "text": "Recent experimental evidence suggests that transcellular propagation of fibrillar protein aggregates drives the progression of neurodegenerative diseases in a prion-like manner. This phenomenon is now well described in cell and animal models and involves the release of protein aggregates into the extracellular space. Free aggregates then enter neighboring cells to seed further fibrillization. The mechanism by which aggregated extracellular proteins such as tau and α-synuclein bind and enter cells to trigger intracellular fibril formation is unknown. Prior work indicates that prion protein aggregates bind heparan sulfate proteoglycans (HSPGs) on the cell surface to transmit pathologic processes. Here, we find that tau fibril uptake also occurs via HSPG binding. This is blocked in cultured cells and primary neurons by heparin, chlorate, heparinase, and genetic knockdown of a key HSPG synthetic enzyme, Ext1. Interference with tau binding to HSPGs prevents recombinant tau fibrils from inducing intracellular aggregation and blocks transcellular aggregate propagation. In vivo, a heparin mimetic, F6, blocks neuronal uptake of stereotactically injected tau fibrils. Finally, uptake and seeding by α-synuclein fibrils, but not huntingtin fibrils, occurs by the same mechanism as tau. This work suggests a unifying mechanism of cell uptake and propagation for tauopathy and synucleinopathy.", "title": "Heparan sulfate proteoglycans mediate internalization and propagation of specific proteopathic seeds." }, { "docid": "42035464", "text": "Microtubule nucleation is the best known function of centrosomes. Centrosomal microtubule nucleation is mediated primarily by gamma tubulin ring complexes (gamma TuRCs). However, little is known about the molecules that anchor these complexes to centrosomes. In this study, we show that the centrosomal coiled-coil protein pericentrin anchors gamma TuRCs at spindle poles through an interaction with gamma tubulin complex proteins 2 and 3 (GCP2/3). Pericentrin silencing by small interfering RNAs in somatic cells disrupted gamma tubulin localization and spindle organization in mitosis but had no effect on gamma tubulin localization or microtubule organization in interphase cells. Similarly, overexpression of the GCP2/3 binding domain of pericentrin disrupted the endogenous pericentrin-gamma TuRC interaction and perturbed astral microtubules and spindle bipolarity. When added to Xenopus mitotic extracts, this domain uncoupled gamma TuRCs from centrosomes, inhibited microtubule aster assembly, and induced rapid disassembly of preassembled asters. All phenotypes were significantly reduced in a pericentrin mutant with diminished GCP2/3 binding and were specific for mitotic centrosomal asters as we observed little effect on interphase asters or on asters assembled by the Ran-mediated centrosome-independent pathway. Additionally, pericentrin silencing or overexpression induced G2/antephase arrest followed by apoptosis in many but not all cell types. We conclude that pericentrin anchoring of gamma tubulin complexes at centrosomes in mitotic cells is required for proper spindle organization and that loss of this anchoring mechanism elicits a checkpoint response that prevents mitotic entry and triggers apoptotic cell death.", "title": "Mitosis-specific anchoring of gamma tubulin complexes by pericentrin controls spindle organization and mitotic entry." } ]

[ { "docid": "11369420", "text": "Acute Myelogenous Leukemia (AML) is an aggressive cancer that strikes both adults and children and is frequently resistant to therapy. Thus, identifying signals needed for AML propagation is a critical step toward developing new approaches for treating this disease. Here, we show that Tetraspanin 3 is a target of the RNA binding protein Musashi 2, which plays a key role in AML. We generated Tspan3 knockout mice that were born without overt defects. However, Tspan3 deletion impaired leukemia stem cell self-renewal and disease propagation and markedly improved survival in mouse models of AML. Additionally, Tspan3 inhibition blocked growth of AML patient samples, suggesting that Tspan3 is also important in human disease. As part of the mechanism, we show that Tspan3 deficiency disabled responses to CXCL12/SDF-1 and led to defects in AML localization within the niche. These identify Tspan3 as an important regulator of aggressive leukemias and highlight a role for Tspan3 in oncogenesis.", "title": "Tetraspanin 3 Is Required for the Development and Propagation of Acute Myelogenous Leukemia." } ]

[ { "docid": "6374918", "text": "The CXCR4-SDF-1 axis plays a central role in the trafficking and retention of normal and malignant stem cells in the bone marrow (BM) microenvironment. Here, we used a mouse model of acute promyelocytic leukemia (APL) and a small molecule competitive antagonist of CXCR4, AMD3100, to examine the interaction of mouse APL cells with the BM microenvironment. APL cells from a murine cathepsin G-PML-RARalpha knockin mouse were genetically modified with firefly luciferase (APL(luc)) to allow tracking by bioluminescence imaging. Coculture of APL(luc) cells with M2-10B4 stromal cells protected the leukemia cells from chemotherapy-induced apoptosis in vitro. Upon injection into syngeneic recipients, APL(luc) cells rapidly migrated to the BM followed by egress to the spleen then to the peripheral blood with death due to leukostasis by day 15. Administration of AMD3100 to leukemic mice induced a 1.6-fold increase in total leukocytes and a 9-fold increase of circulating APL blast counts, which peak at 3 hours and return to baseline by 12 hours. Treatment of leukemic mice with chemotherapy plus AMD3100 resulted in decreased tumor burden and improved overall survival compared with mice treated with chemotherapy alone. These studies provide a proof-of-principle for directing therapy to the critical tethers that promote AML-niche interactions.", "title": "Chemosensitization of acute myeloid leukemia (AML) following mobilization by the CXCR4 antagonist AMD3100." }, { "docid": "8385277", "text": "Fanconi anemia (FA) is a genetic condition associated with bone marrow (BM) failure, myelodysplasia (MDS), and acute myeloid leukemia (AML). We studied 57 FA patients with hypoplastic or aplastic anemia (n = 20), MDS (n = 18), AML (n = 11), or no BM abnormality (n = 8). BM samples were analyzed by karyotype, high-density DNA arrays with respect to paired fibroblasts, and by selected oncogene sequencing. A specific pattern of chromosomal abnormalities was found in MDS/AML, which included 1q+ (44.8%), 3q+ (41.4%), -7/7q (17.2%), and 11q- (13.8%). Moreover, cryptic RUNX1/AML1 lesions (translocations, deletions, or mutations) were observed for the first time in FA (20.7%). Rare mutations of NRAS, FLT3-ITD, MLL-PTD, ERG amplification, and ZFP36L2-PRDM16 translocation, but no TP53, TET2, CBL, NPM1, and CEBPα mutations were found. Frequent homozygosity regions were related not to somatic copy-neutral loss of heterozygosity but to consanguinity, suggesting that homologous recombination is not a common progression mechanism in FA. Importantly, the RUNX1 and other chromosomal/genomic lesions were found at the MDS/AML stages, except for 1q+, which was found at all stages. These data have implications for staging and therapeutic managing in FA patients, and also to analyze the mechanisms of clonal evolution and oncogenesis in a background of genomic instability and BM failure.", "title": "Myelodysplasia and leukemia of Fanconi anemia are associated with a specific pattern of genomic abnormalities that includes cryptic RUNX1/AML1 lesions." }, { "docid": "10795340", "text": "Pancytopenia is a major cause of morbidity in acute myeloid leukemia (AML), yet its cause is unclear. Normal osteoblastic cells have been shown to support hematopoiesis. To define the effects of leukemia on osteoblastic cells, we used an immunocompetent murine model of AML. Leukemic mice had inhibition of osteoblastic cells, with decreased serum levels of the bone formation marker osteocalcin. Osteoprogenitor cells and endosteal-lining osteopontin(+) cells were reduced, and osteocalcin mRNA in CD45(-) marrow cells was diminished. This resulted in severe loss of mineralized bone. Osteoclasts were only transiently increased without significant increases in bone resorption, and their inhibition only partially rescued leukemia-induced bone loss. In vitro data suggested that a leukemia-derived secreted factor inhibited osteoblastic cells. Because the chemokine CCL-3 was recently reported to inhibit osteoblastic function in myeloma, we tested its expression in our model and in AML patients. Consistent with its potential novel role in leukemic-dependent bone loss, CCL-3 mRNA was significantly increased in malignant marrow cells from leukemic mice and from samples from AML patients. Based on these results, we propose that therapeutic mitigation of leukemia-induced uncoupling of osteoblastic and osteoclastic cells may represent a novel approach to promote normal hematopoiesis in patients with myeloid neoplasms.", "title": "Functional inhibition of osteoblastic cells in an in vivo mouse model of myeloid leukemia." }, { "docid": "19510470", "text": "Cancer stem cells have been proposed to be important for initiation, maintenance and recurrence of various malignancies, including acute myeloid leukemia (AML). We have previously reported that CD34+CD38− human primary AML stem cells residing in the endosteal region of the bone marrow are relatively chemotherapy resistant. Using a NOD/SCID/IL2rγnull mouse model of human AML, we now show that the AML stem cells in the endosteal region are cell cycle quiescent and that these stem cells can be induced to enter the cell cycle by treatment with granulocyte colony-stimulating factor (G-CSF). In combination with cell cycle-dependent chemotherapy, G-CSF treatment significantly enhances induction of apoptosis and elimination of human primary AML stem cells in vivo. The combination therapy leads to significantly increased survival of secondary recipients after transplantation of leukemia cells compared with chemotherapy alone.", "title": "Induction of cell cycle entry eliminates human leukemia stem cells in a mouse model of AML" }, { "docid": "13205096", "text": "BACKGROUND In patients with acute myeloid leukemia (AML), the presence or absence of recurrent cytogenetic aberrations is used to identify the appropriate therapy. However, the current classification system does not fully reflect the molecular heterogeneity of the disease, and treatment stratification is difficult, especially for patients with intermediate-risk AML with a normal karyotype. \n METHODS We used complementary-DNA microarrays to determine the levels of gene expression in peripheral-blood samples or bone marrow samples from 116 adults with AML (including 45 with a normal karyotype). We used unsupervised hierarchical clustering analysis to identify molecular subgroups with distinct gene-expression signatures. Using a training set of samples from 59 patients, we applied a novel supervised learning algorithm to devise a gene-expression-based clinical-outcome predictor, which we then tested using an independent validation group comprising the 57 remaining patients. \n RESULTS Unsupervised analysis identified new molecular subtypes of AML, including two prognostically relevant subgroups in AML with a normal karyotype. Using the supervised learning algorithm, we constructed an optimal 133-gene clinical-outcome predictor, which accurately predicted overall survival among patients in the independent validation group (P=0.006), including the subgroup of patients with AML with a normal karyotype (P=0.046). In multivariate analysis, the gene-expression predictor was a strong independent prognostic factor (odds ratio, 8.8; 95 percent confidence interval, 2.6 to 29.3; P<0.001). \n CONCLUSIONS The use of gene-expression profiling improves the molecular classification of adult AML.", "title": "Use of gene-expression profiling to identify prognostic subclasses in adult acute myeloid leukemia." }, { "docid": "11344428", "text": "Leukemia in donor cells (donor cell leukemia; DCL) has been reported as a rare but severe complication of allogeneic stem cell transplantation (SCT). However, the incidence, potential pathogenetic factors, therapeutic options and outcome of patients suffering from DCL and the leukemia risk of their donors are not well defined. A questionnaire survey was carried out within European Blood and Marrow Transplantation Group (EBMT) centers. Ninety-one EBMT centers participated in this survey, covering 10489 allogeneic SCT between 12/1982 and 09/2003. Fourteen cases of DCL, most with a myeloid phenotype (7 cases of acute myeloid leukemia, 3 each of acute lymphocytic leukemia and 1 case of chronic myeloid leukemia) were identified. Demonstration of donor cell origin included molecular analysis of chimerism in most cases. DCL type and cytogenetic alterations were independent from the original disease. The median time between transplantation and diagnosis of DCL was 17 months (4-164). No type of conditioning, donor, graft manipulation, graft-versus-host disease prophylaxis or subsequent complications were identified as risk factors for DCL. Chemotherapy induced remissions in DCL and 2 of 5 patients remain alive in remission after a second transplant. None of the stem cell donors developed hematologic malignancies (median follow-up period of 9 years; range 6-30 years). DCL is an extremely rare complication of allogeneic SCT in which treatment attempts with chemotherapy and a second SCT are justified. Donors are not at an increased risk of developing hematologic malignancies.", "title": "Development of leukemia in donor cells after allogeneic stem cell transplantation--a survey of the European Group for Blood and Marrow Transplantation (EBMT)." }, { "docid": "4387494", "text": "PURPOSE Acute myeloid leukemia (AML) is a heterogeneous disease with poor outcomes. Despite increased evidence shows that dysregulation of histone modification contributes to AML, specific drugs targeting key histone modulators are not applied in the clinical treatment of AML. Here, we investigated whether targeting KDM6B, the demethylase of tri-methylated histone H3 lysine 27 (H3K27me3), has a therapeutic potential for AML. \n METHODS A KDM6B-specific inhibitor, GSK-J4, was applied to treat the primary cells from AML patients and AML cell lines in vitro and in vivo. RNA-sequencing was performed to reveal the underlying mechanisms of inhibiting KDM6B for the treatment of AML. \n RESULTS Here we observed that the mRNA expression of KDM6B was up-regulated in AML and positively correlated with poor survival. Treatment with GSK-J4 increased the global level of H3K27me3 and reduced the proliferation and colony-forming ability of primary AML cells and AML cell lines. GSK-J4 treatment significantly induced cell apoptosis and cell-cycle arrest in Kasumi-1 cells, and displayed a synergistic effect with cytosine arabinoside. Notably, injection of GSK-J4 attenuated the disease progression in a human AML xenograft mouse model in vivo. Treatment with GSK-J4 predominantly resulted in down-regulation of DNA replication and cell-cycle-related pathways, as well as abrogated the expression of critical cancer-promoting HOX genes. ChIP-qPCR validated an increased enrichment of H3K27me3 in the transcription start sites of these HOX genes. \n CONCLUSIONS In summary, our findings suggest that targeting KDM6B with GSK-J4 has a therapeutic potential for the treatment of AML.", "title": "Therapeutic potential of GSK-J4, a histone demethylase KDM6B/JMJD3 inhibitor, for acute myeloid leukemia" }, { "docid": "18806488", "text": "Hoxa9, Meis1 and Pbx1 encode homeodomaincontaining proteins implicated in leukemic transformation in both mice and humans. Hoxa9, Meis1 and Pbx1 proteins have been shown to physically interact with each other, as Hoxa9 cooperatively binds consensus DNA sequences with Meis1 and with Pbx1, while Meis1 and Pbx1 form heterodimers in both the presence and absence of DNA. In this study, we sought to determine if Hoxa9 could transform hemopoietic cells in collaboration with either Pbx1 or Meis1. Primary bone marrow cells, retrovirally engineered to overexpress Hoxa9 and Meis1a simultaneously, induced growth factor-dependent oligoclonal acute myeloid leukemia in <3 months when transplanted into syngenic mice. In contrast, overexpression of Hoxa9, Meis1a or Pbx1b alone, or the combination of Hoxa9 and Pbx1b failed to transform these cells acutely within 6 months post-transplantation. Similar results were obtained when FDC-P1 cells, engineered to overexpress these genes, were transplanted to syngenic recipients. Thus, these studies demonstrate a selective collaboration between a member of the Hox family and one of its DNA-binding partners in transformation of hemopoietic cells.", "title": "Hoxa9 transforms primary bone marrow cells through specific collaboration with Meis1a but not Pbx1b." }, { "docid": "37248765", "text": "N-acetyl-dinaline (CI-994) is an investigational anti-cancer drug which inhibits histone deacetylases. We evaluated the interaction between CI-994 and conventional chemotherapeutics used in acute myeloid leukemia (AML) in a rat model for AML and Brown Norway rat acute myelocytic leukemia (BNML). In vitro, CI-994 in combination with cytarabine (ara-C), daunorubicin and mitoxantrone, resulted in moderate synergism. In vivo, higher dosages of CI-994 induced complete remissions. CI-994/ara-C was very active against BNML. The combinations of CI-994/daunorubicin and CI-994/mitoxantrone were also active against BNML. This study demonstrates favorable in vitro and in vivo interactions between CI-994 and conventional anti-cancer agents used for the treatment of AML.", "title": "CI-994 (N-acetyl-dinaline) in combination with conventional anti-cancer agents is effective against acute myeloid leukemia in vitro and in vivo." }, { "docid": "38745690", "text": "Relapse remains the major cause of mortality for patients with Acute Myeloid Leukemia (AML). Improved tracking of minimal residual disease (MRD) holds the promise of timely treatment adjustments to preempt relapse. Current surveillance techniques detect circulating blasts that coincide with advanced disease and poorly reflect MRD during early relapse. Here, we investigate exosomes as a minimally invasive platform for a microRNA (miRNA) biomarker. We identify a set of miRNA enriched in AML exosomes and track levels of circulating exosome miRNA that distinguish leukemic xenografts from both non-engrafted and human CD34+ controls. We develop biostatistical models that reveal circulating exosomal miRNA at low marrow tumor burden and before circulating blasts can be detected. Remarkably, both leukemic blasts and marrow stroma contribute to serum exosome miRNA. We propose development of serum exosome miRNA as a platform for a novel, sensitive compartment biomarker for prospective tracking and early detection of AML recurrence.", "title": "Serum Exosome MicroRNA as a Minimally-Invasive Early Biomarker of AML" }, { "docid": "43587663", "text": "How the infection risks compare after umbilical cord blood (UCB) and bone marrow (BM) transplantation is not known. Therefore, we compared serious infections in the 2 years after pediatric myeloablative unrelated donor transplantation with unmanipulated BM (n = 52), T cell-depleted (TCD) BM (n = 24), or UCB (n = 60) for the treatment of hematologic malignancy. Overall, the cumulative incidence of 1 or more serious infections was comparable between groups (BM, 81%; TCD, 83%; UCB, 90%; P = .12). Furthermore, by taking all serious infections into account and using multivariate techniques with unmanipulated BM as the reference, there were also no significant differences between groups (TCD relative risk [RR], 1.6; P = .10; UCB RR, 1.0; P = .84). Within the time periods days 0 to 42, days 43 to 100, and days 101 to 180, the only difference was a greater risk of viral infections from days 0 to 42 in TCD recipients (RR, 3.5; P = .02). Notably, after day 180, TCD recipients had a significantly increased infection risk (RR, 3.1; P = .03), whereas the risk in UCB recipients (RR, 0.5; P = .23) was comparable to that in BM recipients. Other factors associated with an increased infection risk in the 2 years after transplantation were age > or = 8 years, graft failure, and severe acute graft-versus-host disease. These data suggest that the risk of serious infection after pediatric UCB transplantation is comparable to that with unmanipulated BM.", "title": "Serious infections after unrelated donor transplantation in 136 children: impact of stem cell source." }, { "docid": "8764879", "text": "Leukemias and other cancers possess self-renewing stem cells that help to maintain the cancer. Cancer stem cell eradication is thought to be crucial for successful anticancer therapy. Using an acute myeloid leukemia (AML) model induced by the leukemia-associated monocytic leukemia zinc finger (MOZ)-TIF2 fusion protein, we show here that AML can be cured by the ablation of leukemia stem cells. The MOZ fusion proteins MOZ-TIF2 and MOZ-CBP interacted with the transcription factor PU.1 to stimulate the expression of macrophage colony–stimulating factor receptor (CSF1R, also known as M-CSFR, c-FMS or CD115). Studies using PU.1-deficient mice showed that PU.1 is essential for the ability of MOZ-TIF2 to establish and maintain AML stem cells. Cells expressing high amounts of CSF1R (CSF1Rhigh cells), but not those expressing low amounts of CSF1R (CSF1Rlow cells), showed potent leukemia-initiating activity. Using transgenic mice expressing a drug-inducible suicide gene controlled by the CSF1R promoter, we cured AML by ablation of CSF1Rhigh cells. Moreover, induction of AML was suppressed in CSF1R-deficient mice and CSF1R inhibitors slowed the progression of MOZ-TIF2–induced leukemia. Thus, in this subtype of AML, leukemia stem cells are contained within the CSF1Rhigh cell population, and we suggest that targeting of PU.1-mediated upregulation of CSF1R expression might be a useful therapeutic approach.", "title": "PU.1-mediated upregulation of CSF1R is crucial for leukemia stem cell potential induced by MOZ-TIF2" }, { "docid": "9460704", "text": "Differentiation therapy has emerged as a powerful way to target specific hematologic malignancies. One of the best examples is the use of all-trans retinoic acid (ATRA) in acute promyelocytic leukemia (APL), which has significantly improved the outcome for patients with this specific form of acute myeloid leukemia (AML). In considering how differentiation therapy could be used in other forms of AML, we predicted that compounds that induce terminal differentiation of megakaryocytes would be effective therapies for the megakaryocytic form of AML, named acute megakaryocytic leukemia (AMKL). We also speculated that such agents would reduce the burden of abnormal hematopoietic cells in primary myelofibrosis and alter the differentiation of megakaryocytes in myelodysplastic syndromes. Using a high-throughput chemical screening approach, we identified small molecules that promoted many features of terminal megakaryocyte differentiation, including the induction of polyploidization, the process by which cells accumulate DNA to 32N or greater. As the induction of polyploidization is an irreversible process, cells that enter this form of the cell cycle do not divide again. Thus, this would be an effective way to reduce the tumor burden. Clinical studies with polyploidy inducers, such as aurora kinase A inhibitors, are under way for a wide variety of malignancies, whereas trials specifically for AMKL and PMF are in development. This novel form of differentiation therapy may be clinically available in the not-too-distant future. Clin Cancer Res; 19(22); 6084-8. ©2013 AACR.", "title": "Molecular pathways: induction of polyploidy as a novel differentiation therapy for leukemia." }, { "docid": "5765455", "text": "Myelodysplastic syndromes (MDS) comprise a heterogeneous group of disorders characterized by ineffective hematopoiesis, with an increased propensity to develop acute myelogenous leukemia (AML). The molecular basis for MDS progression is unknown, but a key element in MDS disease progression is loss of chromosomal material (genomic instability). Using our two-step mouse model for myeloid leukemic disease progression involving overexpression of human mutant NRAS and BCL2 genes, we show that there is a stepwise increase in the frequency of DNA damage leading to an increased frequency of error-prone repair of double-strand breaks (DSB) by nonhomologous end-joining. There is a concomitant increase in reactive oxygen species (ROS) in these transgenic mice with disease progression. Importantly, RAC1, an essential component of the ROS-producing NADPH oxidase, is downstream of RAS, and we show that ROS production in NRAS/BCL2 mice is in part dependent on RAC1 activity. DNA damage and error-prone repair can be decreased or reversed in vivo by N-acetyl cysteine antioxidant treatment. Our data link gene abnormalities to constitutive DNA damage and increased DSB repair errors in vivo and provide a mechanism for an increase in the error rate of DNA repair with MDS disease progression. These data suggest treatment strategies that target RAS/RAC pathways and ROS production in human MDS/AML.", "title": "Reactive oxygen species, DNA damage, and error-prone repair: a model for genomic instability with progression in myeloid leukemia?" }, { "docid": "25148216", "text": "Several members of the Kruppel-like factor (KLF) family of transcription factors play important roles in differentiation, survival, and trafficking of blood and immune cell types. We demonstrate in this study that hematopoietic cells from KLF4(-/-) fetal livers (FL) contained normal numbers of functional hematopoietic progenitor cells, were radioprotective, and performed as well as KLF4(+/+) cells in competitive repopulation assays. However, hematopoietic \"KLF4(-/-) chimeras\" generated by transplantation of KLF4(-/-) fetal livers cells into lethally irradiated wild-type mice completely lacked circulating inflammatory (CD115(+)Gr1(+)) monocytes, and had reduced numbers of resident (CD115(+)Gr1(-)) monocytes. Although the numbers and function of peritoneal macrophages were normal in KLF4(-/-) chimeras, bone marrow monocytic cells from KLF4(-/-) chimeras expressed lower levels of key trafficking molecules and were more apoptotic. Thus, our in vivo loss-of-function studies demonstrate that KLF4, previously shown to mediate proinflammatory signaling in human macrophages in vitro, is essential for differentiation of mouse inflammatory monocytes, and is involved in the differentiation of resident monocytes. In addition, inducible expression of KLF4 in the HL60 human acute myeloid leukemia cell line stimulated monocytic differentiation and enhanced 12-O-tetradecanoylphorbol 13-acetate induced macrophage differentiation, but blocked all-trans-retinoic acid induced granulocytic differentiation of HL60 cells. The inflammation-selective effects of loss-of-KLF4 and the gain-of-KLF4-induced monocytic differentiation in HL60 cells identify KLF4 as a key regulator of monocytic differentiation and a potential target for translational immune modulation.", "title": "Kruppel-like factor 4 is essential for inflammatory monocyte differentiation in vivo." }, { "docid": "24795767", "text": "The current study evaluates the role of quantitative measurement of peripheral lymphocyte subsets, especially CD4+ helper T-cell recovery, in predicting transplant outcomes including overall survival (OS) and non-relapse mortality (NRM) after allogeneic stem cell transplantation. A total of 69 allogeneic recipients were included with following diagnoses: acute myeloid leukemia 42, acute lymphoblastic leukemia 5, chronic myeloid leukemia 15, non-Hodgkin's lymphoma 5 and high-risk myelodysplastic syndrome 2. The peripheral lymphocyte subset counts (CD3+ T cells, CD3+4+ helper T cells, CD3+8+ cytotoxic T cells, CD19+ B cells, and CD56+ natural killer cells) were measured at 3, 6 and 12 months. The CD4+ helper T-cell reconstitution at 3 months was strongly correlated with OS (P<0.0001), NRM (P=0.0007), and opportunistic infections (P=0.0108) at the cutoff value of 200 × 106/l CD4+ helper T cells. Rapid CD4+ helper T-cell recovery was also associated with a higher CD4+ helper T-cell transplant dose (P=0.006) and donor type (P<0.001). An early CD4+ helper T-cell recovery at 3 months correlated with a subsequent faster helper T-cell recovery until 12 months, yet not with B-cell recovery. In a multivariate analysis, rapid recovery of CD4+ helper T cells at 3 months was a favorable prognostic factor together with higher CD34+ cell transplant dose in terms of OS (P=0.001) and NRM (P=0.005).", "title": "Rapid helper T-cell recovery above 200 × 106/l at 3 months correlates to successful transplant outcomes after allogeneic stem cell transplantation" }, { "docid": "27907205", "text": "A monoclonal antibody was raised against cells from an experimental rat myelocytic leukemia (BNML). The major characteristics of the rat leukemia model resemble those of human acute myelocytic leukemia. The monoclonal antibody (MCA) RM124 was characterized with respect to its labeling pattern of BNML leukemia cells, normal rat bone marrow cells, and the hemopoietic stem cell (HSC), by flow cytometric methods and complement-dependent cytotoxicity assays. Flow cytometry revealed a much higher labeling of the leukemic cells by the MCA-RM124 compared with normal bone marrow cells, including CFU-S and CFU-C. Only a subpopulation of the normal granulocytes showed cross reactivity, however, at a lower labeling density. On using the cytotoxicity assays, it was evident that there was a selective killing of leukemic cells as compared with the activity towards the normal hemopoietic stem cells (CFU-S).", "title": "Characteristics of a monoclonal antibody (RM124) against acute myelocytic leukemia cells." }, { "docid": "2559303", "text": "Cellular cardiomyoplasty is an attractive option for the treatment of severe heart failure. It is, however, still unclear and controversial which is the most promising cell source. Therefore, we investigated and examined the fate and functional impact of bone marrow (BM) cells and embryonic stem cell (ES cell)–derived cardiomyocytes after transplantation into the infarcted mouse heart. This proved particularly challenging for the ES cells, as their enrichment into cardiomyocytes and their long-term engraftment and tumorigenicity are still poorly understood. We generated transgenic ES cells expressing puromycin resistance and enhanced green fluorescent protein cassettes under control of a cardiac-specific promoter. Puromycin selection resulted in a highly purified (>99%) cardiomyocyte population, and the yield of cardiomyocytes increased 6–10-fold because of induction of proliferation on purification. Long-term engraftment (4–5 months) was observed when co-transplanting selected ES cell–derived cardiomyocytes and fibroblasts into the injured heart of syngeneic mice, and no teratoma formation was found (n = 60). Although transplantation of ES cell–derived cardiomyocytes improved heart function, BM cells had no positive effects. Furthermore, no contribution of BM cells to cardiac, endothelial, or smooth muscle neogenesis was detected. Hence, our results demonstrate that ES-based cell therapy is a promising approach for the treatment of impaired myocardial function and provides better results than BM-derived cells.", "title": "Engraftment of engineered ES cell–derived cardiomyocytes but not BM cells restores contractile function to the infarcted myocardium" }, { "docid": "17876040", "text": "Owing to their integral involvement in cell cycle regulation, the Polo-like kinase (Plk) family, particularly Plk1, has emerged as an attractive therapeutic target in oncology. In recent years, several Plk1 inhibitors have been developed, with some agents showing encouraging results in early-phase clinical trials. This review focuses on volasertib (BI 6727; an investigational agent), a potent and selective Plk inhibitor. Volasertib has shown promising activity in various cancer cell lines and xenograft models of human cancer. Trials performed to date suggest that volasertib has clinical efficacy in a range of malignancies, with the most promising results seen in patients with acute myeloid leukemia (AML). Encouragingly, recent phase II data have demonstrated that volasertib combined with low-dose cytarabine (LDAC) was associated with higher response rates and improved event-free survival than LDAC alone in patients with previously untreated AML. Based on these observations, and its presumably manageable safety profile, volasertib is currently in phase III development as a potential treatment for patients with AML who are ineligible for intensive remission induction therapy. Given that many patients with AML are of an older age and frail, this constitutes an area of major unmet need. In this review, we discuss the biologic rationale for Plk1 inhibitors in cancer, the clinical development of volasertib to date in solid tumors and AML, and the future identification of biomarkers that might predict response to volasertib and help determine the role of this agent in the clinic.", "title": "Discovery and development of the Polo-like kinase inhibitor volasertib in cancer therapy" } ]

[ { "docid": "12827098", "text": "Despite accumulating evidence suggesting local self-maintenance of tissue macrophages in the steady state, the dogma remains that tissue macrophages derive from monocytes. Using parabiosis and fate-mapping approaches, we confirmed that monocytes do not show significant contribution to tissue macrophages in the steady state. Similarly, we found that after depletion of lung macrophages, the majority of repopulation occurred by stochastic cellular proliferation in situ in a macrophage colony-stimulating factor (M-Csf)- and granulocyte macrophage (GM)-CSF-dependent manner but independently of interleukin-4. We also found that after bone marrow transplantation, host macrophages retained the capacity to expand when the development of donor macrophages was compromised. Expansion of host macrophages was functional and prevented the development of alveolar proteinosis in mice transplanted with GM-Csf-receptor-deficient progenitors. Collectively, these results indicate that tissue-resident macrophages and circulating monocytes should be classified as mononuclear phagocyte lineages that are independently maintained in the steady state.", "title": "Tissue-resident macrophages self-maintain locally throughout adult life with minimal contribution from circulating monocytes." } ]

[ { "docid": "8137081", "text": "Leukocyte trafficking between the various body compartments has an important surveillance function that ensures the detection of antigen and enables the immune system to initiate a rapid and effective response. Repeated social defeat of group-housed male mice induced by daily, acute encounters with an aggressive conspecific substantially altered leukocyte trafficking and led to a gradual redistribution of immune cells in bone marrow, peripheral blood and spleen. Recurrent exposure to the stressor over a period of 2, 4 or 6 consecutive days was associated with cell mobilization and increased myelopoiesis in the bone marrow that was paralleled by an accumulation of neutrophils and monocytes in circulation and spleen. Substantial depletion of B cells in bone marrow and blood was associated with an increase in splenic B cells indicating a redirection of this cell type to the spleen. In contrast, T cells were markedly reduced in these immune compartments. The recruitment of CD11b+ leukocytes (i.e., monocytes/macrophages and neutrophils) from the bone marrow to the spleen might play a critical role in the development of functional glucocorticoid resistance in the murine spleen that was reported in context with repeated social defeat.", "title": "Effects of repeated social stress on leukocyte distribution in bone marrow, peripheral blood and spleen" }, { "docid": "17271462", "text": "The quiescent state is thought to be an indispensable property for the maintenance of hematopoietic stem cells (HSCs). Interaction of HSCs with their particular microenvironments, known as the stem cell niches, is critical for adult hematopoiesis in the bone marrow (BM). Here, we demonstrate that HSCs expressing the receptor tyrosine kinase Tie2 are quiescent and antiapoptotic, and comprise a side-population (SP) of HSCs, which adhere to osteoblasts (OBs) in the BM niche. The interaction of Tie2 with its ligand Angiopoietin-1 (Ang-1) induced cobblestone formation of HSCs in vitro and maintained in vivo long-term repopulating activity of HSCs. Furthermore, Ang-1 enhanced the ability of HSCs to become quiescent and induced adhesion to bone, resulting in protection of the HSC compartment from myelosuppressive stress. These data suggest that the Tie2/Ang-1 signaling pathway plays a critical role in the maintenance of HSCs in a quiescent state in the BM niche.", "title": "Tie2/Angiopoietin-1 Signaling Regulates Hematopoietic Stem Cell Quiescence in the Bone Marrow Niche" }, { "docid": "188911", "text": "Antigen-presenting, major histocompatibility complex (MHC) class II-rich dendritic cells are known to arise from bone marrow. However, marrow lacks mature dendritic cells, and substantial numbers of proliferating less-mature cells have yet to be identified. The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II-negative precursors in marrow. A key step is to remove the majority of nonadherent, newly formed granulocytes by gentle washes during the first 2-4 d of culture. This leaves behind proliferating clusters that are loosely attached to a more firmly adherent \"stroma. \" At days 4-6 the clusters can be dislodged, isolated by 1-g sedimentation, and upon reculture, large numbers of dendritic cells are released. The latter are readily identified on the basis of their distinct cell shape, ultrastructure, and repertoire of antigens, as detected with a panel of monoclonal antibodies. The dendritic cells express high levels of MHC class II products and act as powerful accessory cells for initiating the mixed leukocyte reaction. Neither the clusters nor mature dendritic cells are generated if macrophage colony-stimulating factor rather than granulocyte/macrophage colony-stimulating factor (GM-CSF) is applied. Therefore, GM-CSF generates all three lineages of myeloid cells (granulocytes, macrophages, and dendritic cells). Since > 5 x 10(6) dendritic cells develop in 1 wk from precursors within the large hind limb bones of a single animal, marrow progenitors can act as a major source of dendritic cells. This feature should prove useful for future molecular and clinical studies of this otherwise trace cell type.", "title": "Generation of large numbers of dendritic cells from mouse bone marrow cultures supplemented with granulocyte/macrophage colony-stimulating factor" }, { "docid": "10078024", "text": "Studies of the identity and physiological function of mesenchymal stromal cells (MSCs) have been hampered by a lack of markers that permit both prospective identification and fate mapping in vivo. We found that Leptin Receptor (LepR) is a marker that highly enriches bone marrow MSCs. Approximately 0.3% of bone marrow cells were LepR(+) , 10% of which were CFU-Fs, accounting for 94% of bone marrow CFU-Fs. LepR(+) cells formed bone, cartilage, and adipocytes in culture and upon transplantation in vivo. LepR(+) cells were Scf-GFP(+), Cxcl12-DsRed(high), and Nestin-GFP(low), markers which also highly enriched CFU-Fs, but negative for Nestin-CreER and NG2-CreER, markers which were unlikely to be found in CFU-Fs. Fate-mapping showed that LepR(+) cells arose postnatally and gave rise to most bone and adipocytes formed in adult bone marrow, including bone regenerated after irradiation or fracture. LepR(+) cells were quiescent, but they proliferated after injury. Therefore, LepR(+) cells are the major source of bone and adipocytes in adult bone marrow.", "title": "Leptin-receptor-expressing mesenchymal stromal cells represent the main source of bone formed by adult bone marrow." }, { "docid": "24707550", "text": "Macrophages play a pivotal role in innate and acquired immune responses to Schistosoma mansoni. Classical (M1) or alternative (M2) activation states of these cells further delineate their roles in tissue damage through innate immunity or fibrotic remodeling, respectively. In the present study, we addressed the following question: Does systemic Th2-type cytokine polarization evoked by S. mansoni affect macrophage differentiation and activation? To this end, we analyzed bone marrow-derived macrophages from mice with S. mansoni egg-induced pulmonary granulomas and unchallenged (or naïve) mice to determine their activation state and their response to specific TLR agonists, including S. mansoni egg antigens. Unlike naïve macrophages, macrophages from Th2-polarized mice constitutively expressed significantly higher \"found in inflammatory zone-1\" (FIZZ1) and ST2 (M2 markers) and significantly lower NO synthase 2, CCL3, MIP-2, TNF-alpha, and IL-12 (M1 markers). Also, compared with naïve macrophages, Th2-polarized macrophages exhibited enhanced responses to the presence of specific TLR agonists, which consistently induced significantly higher levels of gene and protein levels for M2 and M1 markers in these cells. Together, these data show that signals received by bone marrow precursors during S. mansoni egg-induced granuloma responses dynamically alter the development of macrophages and enhance the TLR responsiveness of these cells, which may ultimately have a significant effect on the pulmonary granulomatous response.", "title": "A systemic granulomatous response to Schistosoma mansoni eggs alters responsiveness of bone-marrow-derived macrophages to Toll-like receptor agonists." }, { "docid": "3118719", "text": "E-cadherin is best characterized as adherens junction protein, which through homotypic interactions contributes to the maintenance of the epithelial barrier function. In epithelial cells, the cytoplasmic tail of E-cadherin forms a dynamic complex with catenins and regulates several intracellular signal transduction pathways, including Wnt/β-catenin, PI3K/Akt, Rho GTPase, and NF-κB signaling. Recent progress uncovered a novel and critical role for this adhesion molecule in mononuclear phagocyte functions. E-cadherin regulates the maturation and migration of Langerhans cells, and its ligation prevents the induction of a tolerogenic state in bone marrow-derived dendritic cells (DCs). In this respect, the functionality of β-catenin could be instrumental in determining the balance between immunogenicity and tolerogenicity of DCs in vitro and in vivo. Fusion of alternatively activated macrophages and osteoclasts is also E-cadherin-dependent. In addition, the E-cadherin ligands CD103 and KLRG1 are expressed on DC-, T-, and NK-cell subsets and contribute to their interaction with E-cadherin-expressing DCs and macrophages. Here we discuss the regulation, function, and implications of E-cadherin expression in these central orchestrators of the immune system.", "title": "Regulation and function of the E-cadherin/catenin complex in cells of the monocyte-macrophage lineage and DCs." }, { "docid": "46193388", "text": "Bone marrow stem cells give rise to a variety of hematopoietic lineages and repopulate the blood throughout adult life. We show that, in a strain of mice incapable of developing cells of the myeloid and lymphoid lineages, transplanted adult bone marrow cells migrated into the brain and differentiated into cells that expressed neuron-specific antigens. These findings raise the possibility that bone marrow-derived cells may provide an alternative source of neurons in patients with neurodegenerative diseases or central nervous system injury.", "title": "Turning blood into brain: cells bearing neuronal antigens generated in vivo from bone marrow." }, { "docid": "1122198", "text": "Macrophage-derived foam cells express apolipoprotein E (apoE) abundantly in atherosclerotic lesions. To examine the physiologic role of apoE secretion by the macrophage in atherogenesis, bone marrow transplantation was used to reconstitute C57BL/6 mice with macrophages that were either null or wild type for the apoE gene. After 13 weeks on an atherogenic diet, C57BL/6 mice reconstituted with apoE null marrow developed 10-fold more atherosclerosis than controls in the absence of significant differences in serum cholesterol levels or lipoprotein profiles. ApoE expression was absent in the macrophage-derived foam cells of C57BL/6 mice reconstituted with apoE null marrow. Thus, lack of apoE expression by the macrophage promotes foam cell formation. These data support a protective role for apoE expression by the macrophage in early atherogenesis.", "title": "Increased atherosclerosis in mice reconstituted with apolipoprotein E null macrophages." }, { "docid": "44562221", "text": "Endogenous glucocorticoids (GC) play an important role in the termination of the inflammatory response following infection and tissue injury. However, recent findings indicate that stress can impair the anti-inflammatory capacities of these hormones. Lipopolysaccharide (LPS)-stimulated splenocytes of mice that were repeatedly subjected to social disruption (SDR) stress were less sensitive to the immunosuppressive effects of corticosterone (CORT) as demonstrated by an increased production of pro-inflammatory cytokines and enhanced cell survival. Myeloid cells expressing the marker CD11b were shown to play a key role in this process. Here we investigated the role of the bone marrow as a potential source of the GC-insensitive cells. The study revealed that LPS-stimulated bone marrow cells, in the absence of experimental stress, were virtually GC-resistant and retained high levels of cell viability after treatment with CORT. Recurrent exposure to the acute stressor over a period of 2, 4 or 6 days led to an increase in the GC sensitivity of the bone marrow cells. This increase in GC sensitivity was associated with enhanced mRNA expression of granulocyte-macrophage colony-stimulating factor (GM-CSF), an increase in the number of myeloid progenitors, and a decrease in the proportion of mature CD11b+ cells. The changes in the cellular composition of the bone marrow were accompanied by an increase in splenic CD11b+ cell numbers. Simultaneous assessment of the GC sensitivity in bone marrow and spleen revealed a significant negative correlation between both tissues suggesting that social stress causes the redistribution of GC-insensitive myeloid cells from the bone marrow to the spleen.", "title": "Tissue-specific alterations in the glucocorticoid sensitivity of immune cells following repeated social defeat in mice" }, { "docid": "6270720", "text": "RATIONALE The myeloid differentiation factor (MyD)88/interleukin (IL)-1 axis activates self-antigen-presenting cells and promotes autoreactive CD4(+) T-cell expansion in experimental autoimmune myocarditis, a mouse model of inflammatory heart disease. \n OBJECTIVE The aim of this study was to determine the role of MyD88 and IL-1 in the progression of acute myocarditis to an end-stage heart failure. \n METHODS AND RESULTS Using alpha-myosin heavy chain peptide (MyHC-alpha)-loaded, activated dendritic cells, we induced myocarditis in wild-type and MyD88(-/-) mice with similar distributions of heart-infiltrating cell subsets and comparable CD4(+) T-cell responses. Injection of complete Freund's adjuvant (CFA) or MyHC-alpha/CFA into diseased mice promoted cardiac fibrosis, induced ventricular dilation, and impaired heart function in wild-type but not in MyD88(-/-) mice. Experiments with chimeric mice confirmed the bone marrow origin of the fibroblasts replacing inflammatory infiltrates and showed that MyD88 and IL-1 receptor type I signaling on bone marrow-derived cells was critical for development of cardiac fibrosis during progression to heart failure. \n CONCLUSIONS Our findings indicate a critical role of MyD88/IL-1 signaling in the bone marrow compartment in postinflammatory cardiac fibrosis and heart failure and point to novel therapeutic strategies against inflammatory cardiomyopathy.", "title": "Myeloid differentiation factor-88/interleukin-1 signaling controls cardiac fibrosis and heart failure progression in inflammatory dilated cardiomyopathy." }, { "docid": "9412420", "text": "Mesenchymal stem cells (MSCs) commonly defined by in vitro functions have entered clinical application despite little definition of their function in residence. Here, we report genetic pulse-chase experiments that define osteoblastic cells as short-lived and nonreplicative, requiring replenishment from bone-marrow-derived, Mx1(+) stromal cells with \"MSC\" features. These cells respond to tissue stress and migrate to sites of injury, supplying new osteoblasts during fracture healing. Single cell transplantation yielded progeny that both preserve progenitor function and differentiate into osteoblasts, producing new bone. They are capable of local and systemic translocation and serial transplantation. While these cells meet current definitions of MSCs in vitro, they are osteolineage restricted in vivo in growing and adult animals. Therefore, bone-marrow-derived MSCs may be a heterogeneous population with the Mx1(+) population, representing a highly dynamic and stress responsive stem/progenitor cell population of fate-restricted potential that feeds the high cell replacement demands of the adult skeleton.", "title": "Endogenous bone marrow MSCs are dynamic, fate-restricted participants in bone maintenance and regeneration." }, { "docid": "20186814", "text": "Muscle satellite cells have long been considered a distinct myogenic lineage responsible for postnatal growth, repair, and maintenance of skeletal muscle. Recent studies in mice, however, have revealed the potential for highly purified hematopoietic stem cells from bone marrow to participate in muscle regeneration. Perhaps more significantly, a population of putative stem cells isolated directly from skeletal muscle efficiently reconstitutes the hematopoietic compartment and participates in muscle regeneration following intravenous injection in mice. The plasticity of muscle stem cells has raised important questions regarding the relationship between the muscle-derived stem cells and the skeletal muscle satellite cells. Furthermore, the ability of hematopoietic cells to undergo myogenesis has prompted new investigations into the embryonic origin of satellite cells. Recent developmental studies suggest that a population of satellite cells is derived from progenitors in the embryonic vasculature. Taken together, these studies provide the first evidence that pluripotential stem cells are present within adult skeletal muscle. Tissue-specific stem cells, including satellite cells, may share a common embryonic origin and possess the capacity to activate diverse genetic programs in response to environmental stimuli. Manipulation of such tissue-specific stem cells may eventually revolutionize therapies for degenerative diseases, including muscular dystrophy.", "title": "A new look at the origin, function, and \"stem-cell\" status of muscle satellite cells." }, { "docid": "35811036", "text": "Embryonic-like stem cell (ELSC), expressing part of surface markers of human embryonic stem cells, may be a better candidate for cell therapy of degenerative muscular disease than mesenchymal stem cell (MSC). We isolated ELSC and MSC from bone marrow, respectively, and compared their differences in the characteristics and the capacity of myogenic differentiation. Results showed that ELSC could be isolated successfully from 3 adult bone marrow samples by using serum-free medium with 10ng/ml basic fibroblast growth factor (bFGF). At the same cell density, MSC could also be isolated from the same samples by using DMEM/F12 medium containing 10% new cattle serum. However, ELSC appeared as small, morphologically slenderer, upregulated expression of SSEA-4 and ultramicroscopically more immature than MSC derived from the same samples. Immunofluorescent staining and RT-PCR analysis showed ELSC weakly expressed Oct-4, Nanog-3 and Sox-2. Moreover, ELSC and MSC could be induced into long, multinucleated fibers expressing myogenin and myosin heavy chain (MHC) in myogenic differentiation medium, but by day 10, proportion of multinucleated fibers positive for MHC was respectively 25.0%+/-6.9% and 13.8%+/-7.6% in ELSC and MSC culture. These data suggest that bone marrow derived ELSC represent an ideal candidate for cell therapy of degenerative muscular disease.", "title": "Embryonic-like stem cell derived from adult bone marrow: immature morphology, cell surface markers, ultramicrostructure and differentiation into multinucleated fibers in vitro." }, { "docid": "43619625", "text": "Activated T cells secrete multiple osteoclastogenic cytokines which play a major role in the bone destruction associated with rheumatoid arthritis. While the role of T cells in osteoclastogenesis has received much attention recently, the effect of T cells on osteoblast formation and activity is poorly defined. In this study, we investigated the hypothesis that in chronic inflammation activated T cells contribute to enhanced bone turnover by promoting osteoblastic differentiation. We show that T cells produce soluble factors that induce alkaline phosphatase activity in bone marrow stromal cells and elevated expression of mRNA for Runx2 and osteocalcin. This data indicate that T cell derived factors have the capacity to stimulate the differentiation of bone marrow stromal cells into the osteoblast phenotype. RANKL mRNA was undetectable under any conditions in highly purified bone marrow stromal cells. In contrast, RANKL was constitutively expressed in primary osteoblasts and only moderately up-regulated by activated T cell conditioned medium. Interestingly, both bone marrow stromal cells and osteoblasts expressed mRNA for RANK, which was strongly up-regulated in both cell types by activated T cell conditioned medium. Although, mRNA for the RANKL decoy receptor, osteoprotegerin, was also up-regulated by activated T cell conditioned medium, it's inhibitory effects may be mitigated by a simultaneous rise in the osteoprotegerin competitor TNF-related apoptosis-inducing ligand. Based on our data we propose that during chronic inflammation, T cells regulate bone loss by a dual mechanism involving both direct stimulation of osteoclastogenesis, by production of osteoclastogenic cytokines, and indirectly by induction of osteoblast differentiation and up-regulation of bone turnover via coupling.", "title": "Inflammatory T cells rapidly induce differentiation of human bone marrow stromal cells into mature osteoblasts." }, { "docid": "2853291", "text": "Mesenchymal stem cells (MSCs) and osteolineage cells contribute to the hematopoietic stem cell (HSC) niche in the bone marrow of long bones. However, their developmental relationships remain unclear. In this study, we demonstrate that different MSC populations in the developing marrow of long bones have distinct functions. Proliferative mesoderm-derived nestin(-) MSCs participate in fetal skeletogenesis and lose MSC activity soon after birth. In contrast, quiescent neural crest-derived nestin(+) cells preserve MSC activity, but do not generate fetal chondrocytes. Instead, they differentiate into HSC niche-forming MSCs, helping to establish the HSC niche by secreting Cxcl12. Perineural migration of these cells to the bone marrow requires the ErbB3 receptor. The neonatal Nestin-GFP(+) Pdgfrα(-) cell population also contains Schwann cell precursors, but does not comprise mature Schwann cells. Thus, in the developing bone marrow HSC niche-forming MSCs share a common origin with sympathetic peripheral neurons and glial cells, and ontogenically distinct MSCs have non-overlapping functions in endochondrogenesis and HSC niche formation.", "title": "The neural crest is a source of mesenchymal stem cells with specialized hematopoietic stem cell niche function" }, { "docid": "42465769", "text": "Adipocytes are part of hematopoietic microenvironment, even though up to now in humans, their role in hematopoiesis is still questioned. We have previously shown that accumulation of fat cells in femoral bone marrow (BM) coincides with increased expression of neuropilin-1 (NP-1), while it is weakly expressed in hematopoietic iliac crest BM. Starting from this observation, we postulated that adipocytes might exert a negative effect on hematopoiesis mediated through NP-1. To test this hypothesis, we set up BM adipocytes differentiated into fibroblast-like fat cells (FLFC), which share the major characteristics of primitive unilocular fat cells, as an experimental model. As expected, FLFCs constitutively produced macrophage colony stimulating factor and induced CD34(+) differentiation into macrophages independently of cell-to-cell contact. By contrast, granulopoiesis was hampered by cell-to-cell contact but could be restored in transwell culture conditions, together with granulocyte colony stimulating factor production. Both functions were also recovered when FLFCs cultured in contact with CD34(+) cells were treated with an antibody neutralizing NP-1, which proved its critical implication in contact inhibition. An inflammatory cytokine such as interleukin-1 beta or dexamethasone modulates FLFC properties to restore granulopoiesis. Our data provide the first evidence that primary adipocytes exert regulatory functions during hematopoiesis that might be implicated in some pathological processes. Disclosure of potential conflicts of interest is found at the end of this article.", "title": "Human bone marrow adipocytes block granulopoiesis through neuropilin-1-induced granulocyte colony-stimulating factor inhibition." }, { "docid": "25068298", "text": "Distribution and fine structure of macrophages were studied in 10 human embryos in the 6th and 7th week of gestation, 5.5 to 12 mm in crown-rump length. The yolk sac macrophages were found in the extravascular mesenchymal tissues and intravascular spaces long before the first appearance of bone marrow and lymphatic tissues in the embryos. In addition to the macrophages, the fibroblastic cells and the cells of erythropoietic series were also present in the extravascular space. The macrophages showed a variety of cellular structures suggesting transition from immature cell type with no heterophagolysosomes to mature cell type in phagocytosis. The mature macrophages avidly phagocytized the primitive erythroblasts and occasionally platelets. They were positively stained for lysosomal enzymes and were characterized by numerous pleomorphic heterophagolysosomes which exhibited various stages of digestion of phagocytized blood cells. The origin of intravascular macrophages may be in either migrated extravascular macrophages or phagocytic endothelial cells. The phagocytosis and degradation of erythroblasts appear to be one of the main functions of yolk sac macrophages. The presence of the macrophages in mitosis indicates their proliferation in situ.", "title": "Electron microscopic studies of macrophages in early human yolk sacs." }, { "docid": "24466904", "text": "We used bone marrow biopsies instead of mononuclear cells to maintain long-term cultures from 103 patients belonging to all five sub-categories of myelodysplastic syndromes (MDS), as well as 12 normal controls. By week 4, 30-50% confluency was reached and could be maintained for up to 12 weeks with 100% confluency. The four prominent cells were fibroblasts, macrophages, endothelial cells and adipocytes. Immunohistochemical and electron microscopic studies provided lineage confirmation. Normal hematopoiesis was well supported by MDS stroma. Neither the FAB nor cytogenetics was co-related with the potency of growth. MDS stroma appears to be both morphologically and functionally normal.", "title": "Successful establishment of long-term bone marrow cultures in 103 patients with myelodysplastic syndromes." }, { "docid": "3495456", "text": "Summary Neutrophils are specialized innate cells that require constant replenishment from proliferative bone marrow (BM) precursors as a result of their short half‐life. Although it is established that neutrophils are derived from the granulocyte‐macrophage progenitor (GMP), the differentiation pathways from GMP to functional mature neutrophils are poorly defined. Using mass cytometry (CyTOF) and cell‐cycle‐based analysis, we identified three neutrophil subsets within the BM: a committed proliferative neutrophil precursor (preNeu) which differentiates into non‐proliferating immature neutrophils and mature neutrophils. Transcriptomic profiling and functional analysis revealed that preNeu require the C/EBP&egr; transcription factor for their generation from the GMP, and their proliferative program is substituted by a gain of migratory and effector function as they mature. preNeus expand under microbial and tumoral stress, and immature neutrophils are recruited to the periphery of tumor‐bearing mice. In summary, our study identifies specialized BM granulocytic populations that ensure supply under homeostasis and stress responses. Graphical Abstract Figure. No Caption available. HighlightsProliferation activity identifies committed neutrophil precursor in mice and humansNeutrophil subsets possess distinct transcriptomic and functional signaturesDefect in neutrophil development leads to impaired neutrophil‐mediated responsesIncreased circulating immature neutrophils are associated with cancer progression &NA; The neutrophil differentiation pathway is poorly defined. Evrard et. al. demonstrate a workflow of characterizing bone marrow neutrophil subsets on the basis of their proliferative capacity and molecular signatures and thereby define the developmental trajectory and functional properties of neutrophils.", "title": "Developmental Analysis of Bone Marrow Neutrophils Reveals Populations Specialized in Expansion, Trafficking, and Effector Functions" } ]

[ { "docid": "16855829", "text": "Bullying is still prevalent in schools and is clearly stressful for victims. 1 2 It may also have undesirable consequences for bullies, with antisocial behaviour persisting into adulthood. Victims are generally reported to be weaker than the bullies. 2 3 This would suggest that very short pupils are more likely to be victims and less likely to be the aggressors. The Wessex growth study allowed us to examine the prevalence of bullying, as experienced or perpetrated by pupils of different heights. Ninety two short normal adolescents who had been below the third centile for height at school entry4 and 117 controls matched for age and sex completed a bullying questionnaire, derived from work by Whitney and Smith.5 There were no refusals or any significant differences in sex or social class between the groups. Mean age (range) was 14.7 (13.4-15.7) years. Mean height SD scores were: short pupils −1.90 (−3.53 to −0.01), controls 0.31 (−1.41 …", "title": "Bullying in school: are short pupils at risk? Questionnaire study in a cohort." } ]

[ { "docid": "2867345", "text": "BACKGROUND A sexual dimorphism exists in the incidence and prevalence of coronary artery disease--men are more commonly affected than are age-matched women. We explored the role of the Y chromosome in coronary artery disease in the context of this sexual inequity. \n METHODS We genotyped 11 markers of the male-specific region of the Y chromosome in 3233 biologically unrelated British men from three cohorts: the British Heart Foundation Family Heart Study (BHF-FHS), West of Scotland Coronary Prevention Study (WOSCOPS), and Cardiogenics Study. On the basis of this information, each Y chromosome was tracked back into one of 13 ancient lineages defined as haplogroups. We then examined associations between common Y chromosome haplogroups and the risk of coronary artery disease in cross-sectional BHF-FHS and prospective WOSCOPS. Finally, we undertook functional analysis of Y chromosome effects on monocyte and macrophage transcriptome in British men from the Cardiogenics Study. \n FINDINGS Of nine haplogroups identified, two (R1b1b2 and I) accounted for roughly 90% of the Y chromosome variants among British men. Carriers of haplogroup I had about a 50% higher age-adjusted risk of coronary artery disease than did men with other Y chromosome lineages in BHF-FHS (odds ratio 1·75, 95% CI 1·20-2·54, p=0·004), WOSCOPS (1·45, 1·08-1·95, p=0·012), and joint analysis of both populations (1·56, 1·24-1·97, p=0·0002). The association between haplogroup I and increased risk of coronary artery disease was independent of traditional cardiovascular and socioeconomic risk factors. Analysis of macrophage transcriptome in the Cardiogenics Study revealed that 19 molecular pathways showing strong differential expression between men with haplogroup I and other lineages of the Y chromosome were interconnected by common genes related to inflammation and immunity, and that some of them have a strong relevance to atherosclerosis. \n INTERPRETATION The human Y chromosome is associated with risk of coronary artery disease in men of European ancestry, possibly through interactions of immunity and inflammation. \n FUNDING British Heart Foundation; UK National Institute for Health Research; LEW Carty Charitable Fund; National Health and Medical Research Council of Australia; European Union 6th Framework Programme; Wellcome Trust.", "title": "Inheritance of coronary artery disease in men: an analysis of the role of the Y chromosome" }, { "docid": "12789595", "text": "It is becoming “a truth universally acknowledged” that the education of undergraduate medical students will be enhanced through the use of computer assisted learning. Access to the wide range of online options illustrated in the figure must surely make learning more exciting, effective, and likely to be retained. This assumption is potentially but by no means inevitably correct. ### Box 1: Why fund computer assisted learning? Computer assisted learning is inevitable —Individual lecturers and departments are already beginning to introduce a wide range of computer based applications, sometimes in a haphazard way. Planned and coordinated development is better than indiscriminate expansion It is convenient and flexible —Courses supported by computer assisted learning applications may require fewer face to face lectures and seminars and place fewer geographical and temporal constraints on staff and students. Students at peripheral hospitals or primary care centres may benefit in particular Unique presentational benefits —Computer presentation is particularly suited to subjects that are visually intensive, detail oriented, and difficult to conceptualise, such as complex biochemical processes or microscopic images.1 Furthermore, “virtual” cases may reduce the need to use animal or human tissue in learning Personalised learning —Each learner can progress at his or her preferred pace. They can repeat, interrupt, and resume at will, which may have particular advantages for weaker students Economies of scale —Once an application has been set up, the incremental cost of offering it to additional students is relatively small Competitive advantage —Potential applicants may use the quality of information technology to discriminate between medical schools. A “leading edge” virtual campus is likely to attract good students Achieves the ultimate goal of higher education —The goal is to link people into learning communities. Computer applications, especially the internet and world wide web, are an extremely efficient way of doing this2 Expands pedagogical horizons —The most controversial argument for … RETURN TO TEXT", "title": "Computer assisted learning in undergraduate medical education." }, { "docid": "17374970", "text": "AIM To determine attrition and predictors of academic success among medical students at University of Split, Croatia. \n METHODS We analysed academic records of 2054 students enrolled during 1979-2008 period. \n RESULTS We found that 26% (533/2054) of enrolled students did not graduate. The most common reasons for attrition were 'personal' (36.4%), transfer to another medical school (35.6%), and dismissal due to unsatisfactory academic record (21.2%). Grade point average (GPA) and study duration of attrition students were significantly associated with parental education. There were 1126 graduates, 395 men and 731 women. Their average graduation GPA was 3.67±0.53 and study duration 7.6±2.44 years. During 5-year curriculum only 6.4% (42/654) of students graduated in time, and 55% (240/472) of students graduated in time after curriculum was extended to 6 years. Variables predicting whether a student will graduate or not were high school grades, entrance exam score and year of enrollment. Significant predictors of graduation grades were high school grades and entrance exam score. Entrance exam score predicted length of studying. \n CONCLUSION Preadmission academic qualifications and year of enrollment predict academic success in medical school. More attention should be devoted to high attrition.", "title": "Predictors of Attrition and Academic Success of Medical Students: A 30-Year Retrospective Study" }, { "docid": "24159217", "text": "CONTEXT No randomized controlled studies have been conducted to date on the effectiveness of psychological interventions for children with symptoms of posttraumatic stress disorder (PTSD) that has resulted from personally witnessing or being personally exposed to violence. \n OBJECTIVE To evaluate the effectiveness of a collaboratively designed school-based intervention for reducing children's symptoms of PTSD and depression that has resulted from exposure to violence. \n DESIGN A randomized controlled trial conducted during the 2001-2002 academic year. \n SETTING AND PARTICIPANTS Sixth-grade students at 2 large middle schools in Los Angeles who reported exposure to violence and had clinical levels of symptoms of PTSD. \n INTERVENTION Students were randomly assigned to a 10-session standardized cognitive-behavioral therapy (the Cognitive-Behavioral Intervention for Trauma in Schools) early intervention group (n = 61) or to a wait-list delayed intervention comparison group (n = 65) conducted by trained school mental health clinicians. \n MAIN OUTCOME MEASURES Students were assessed before the intervention and 3 months after the intervention on measures assessing child-reported symptoms of PTSD (Child PTSD Symptom Scale; range, 0-51 points) and depression (Child Depression Inventory; range, 0-52 points), parent-reported psychosocial dysfunction (Pediatric Symptom Checklist; range, 0-70 points), and teacher-reported classroom problems using the Teacher-Child Rating Scale (acting out, shyness/anxiousness, and learning problems; range of subscales, 6-30 points). \n RESULTS Compared with the wait-list delayed intervention group (no intervention), after 3 months of intervention students who were randomly assigned to the early intervention group had significantly lower scores on symptoms of PTSD (8.9 vs 15.5, adjusted mean difference, - 7.0; 95% confidence interval [CI], - 10.8 to - 3.2), depression (9.4 vs 12.7, adjusted mean difference, - 3.4; 95% CI, - 6.5 to - 0.4), and psychosocial dysfunction (12.5 vs 16.5, adjusted mean difference, - 6.4; 95% CI, -10.4 to -2.3). Adjusted mean differences between the 2 groups at 3 months did not show significant differences for teacher-reported classroom problems in acting out (-1.0; 95% CI, -2.5 to 0.5), shyness/anxiousness (0.1; 95% CI, -1.5 to 1.7), and learning (-1.1, 95% CI, -2.9 to 0.8). At 6 months, after both groups had received the intervention, the differences between the 2 groups were not significantly different for symptoms of PTSD and depression; showed similar ratings for psychosocial function; and teachers did not report significant differences in classroom behaviors. \n CONCLUSION A standardized 10-session cognitive-behavioral group intervention can significantly decrease symptoms of PTSD and depression in students who are exposed to violence and can be effectively delivered on school campuses by trained school-based mental health clinicians.", "title": "A mental health intervention for schoolchildren exposed to violence: a randomized controlled trial." }, { "docid": "24510595", "text": "PURPOSE Patients with daily or near-daily headaches are commonly seen in neurology practices and in headache subspecialty centers, but there is little information on the prevalence of this condition in the general population. We present the first US-based study describing the prevalence and characteristics of frequent headache in the general population. \n METHODS In Baltimore County, Maryland, 13 343 individuals 18 to 65 years of age were selected by random-digit dialing and interviewed by telephone about their headaches. Subjects reporting 180 or more headaches per year were classified as having frequent headache. Three mutually exclusive subtypes of frequent headache were identified: frequent headache with migrainous features, chronic tension-type headache, and unclassified frequent headache. \n RESULTS The overall prevalence of frequent headache was 4.1% (5.0% female, 2.8% male; 1.8:1 female to male ratio). Frequent headache was 33% more common in Caucasians (4.4%) than in African Americans (3.3%). In both males and females, prevalence was highest in the lowest educational category. Among frequent headache sufferers, more than half (52% female, 56% male) met criteria for chronic tension-type headache, almost one third (33% female, 25% male) met criteria for frequent headache with migrainous features, and the remainder (15% female, 19% male) were unclassified. Overall, 30% of female and 25% of male frequent headache sufferers met International Headache Society (IHS) criteria for migraine (with or without aura). \n CONCLUSIONS Frequent headache is common in the general population and is more prevalent in Caucasians and in those with less than a high school education. Chronic tension-type headache is more common than frequent headache with migrainous features, though the latter is more disabling. Although more common in females than males, the female preponderance of frequent headache is less marked than in migraine. The sex ratio varies by frequent headache subtype.", "title": "Prevalence of frequent headache in a population sample." }, { "docid": "36558211", "text": "OBJECTIVES To explore the different characteristics of high and low fat consumers, in particular their macronutrient intake and body mass index. \n DESIGN Reanalysis of data from the Dietary and Nutritional Survey of British Adults. Comparisons were made between groups defined as high and low fat consumers on the basis of 7-day weighed food records considered to be valid for energy intake. Individuals were classified in two ways according to the percentage energy from fat (FAT%) and the absolute amount of fat consumed (FATg). The criteria for classification of the high FAT% being > 45% (high fat) and < or = 35% (low fat). For the FATg group the threshold for the high fat group was > 138 g/day (men) and > 102 g/day (women), and for the low fat group < 85 g/day (men) and < 70 g/day (women). \n SETTING Dietary data was collected from private households in Great Britain between 1986 and 1987. SUBJECTS From the total population of 2197, individuals who were slimming, ill or had an EI: BMR of < 1.2 were excluded in order to use data which was most likely to represent habitual energy intakes. From the remaining 1240 subjects, 10.8% of this sample (6.1% of the total population) were classified as low fat consumers (76 men and 58 women) and 15.4% high fat (8.7% of the total population, 93 men and 98 women). \n MAIN OUTCOME MEASURES Macronutrient consumption and body mass index (BMI). \n RESULTS 30% of the subjects changed fat group classification when the criteria of defining high and low fat groups altered from FAT% to FATg. Nutrient intakes differed according to definition of the groups. The high fat FATg group ate significantly more of all nutrients than the low fat FATg group. However, this was not seen for the FAT% analysis, with the high fat group eating more fat and less carbohydrate. The average BMI tended to be higher in the high fat than the low fat groups, particularly in the FATg analysis. However, the high fat group contained a wide range of BMIs. Further exploration of BMI in the high fat groups, showed that age (an 11-year difference) was the only variable to distinguish individuals in the top and bottom quartiles of BMI. \n CONCLUSIONS High and low fat consumers differ according to a number of variables, and this is affected by how these groups are defined (FAT% or FATg). High fat consumers tend to have a higher BMI than low fat consumers, but not all high fat consumers are overweight or obese.", "title": "High and low fat consumers, their macronutrient intake and body mass index: further analysis of the National Diet and Nutrition Survey of British Adults." }, { "docid": "2295434", "text": "myfood24 Is an online 24-h dietary assessment tool developed for use among British adolescents and adults. Limited information is available regarding the validity of using new technology in assessing nutritional intake among adolescents. Thus, a relative validation of myfood24 against a face-to-face interviewer-administered 24-h multiple-pass recall (MPR) was conducted among seventy-five British adolescents aged 11-18 years. Participants were asked to complete myfood24 and an interviewer-administered MPR on the same day for 2 non-consecutive days at school. Total energy intake (EI) and nutrients recorded by the two methods were compared using intraclass correlation coefficients (ICC), Bland-Altman plots (using between and within-individual information) and weighted κ to assess the agreement. Energy, macronutrients and other reported nutrients from myfood24 demonstrated strong agreement with the interview MPR data, and ICC ranged from 0·46 for Na to 0·88 for EI. There was no significant bias between the two methods for EI, macronutrients and most reported nutrients. The mean difference between myfood24 and the interviewer-administered MPR for EI was -230 kJ (-55 kcal) (95 % CI -490, 30 kJ (-117, 7 kcal); P=0·4) with limits of agreement ranging between 39 % (3336 kJ (-797 kcal)) lower and 34 % (2874 kJ (687 kcal)) higher than the interviewer-administered MPR. There was good agreement in terms of classifying adolescents into tertiles of EI (κ w =0·64). The agreement between day 1 and day 2 was as good for myfood24 as for the interviewer-administered MPR, reflecting the reliability of myfood24. myfood24 Has the potential to collect dietary data of comparable quality with that of an interviewer-administered MPR.", "title": "Agreement between an online dietary assessment tool (myfood24) and an interviewer-administered 24-h dietary recall in British adolescents aged 11-18 years." }, { "docid": "6710713", "text": "OBJECTIVE To determine whether there are risk factors in a doctor's time at medical school that are associated with subsequent professional misconduct. \n DESIGN Matched case-control study. Setting Records from medical schools and the General Medical Council (GMC). \n PARTICIPANTS 59 doctors who had graduated from any one of eight medical schools in the United Kingdom in 1958-97 and had a proved finding of serious professional misconduct in GMC proceedings in 1999-2004 (cases); 236 controls (four for each case) were selected by systematic sampling from matching graduation cohorts. Case-control status was revealed by the GMC after completion of data entry. \n MAIN OUTCOME MEASURE Odds ratios for being a \"case,\" with multivariable conditional logistic regression of potential risk factors including pre-admission characteristics and progress during the course. These data were obtained from anonymised copies of the students' progress files held by their original medical schools. \n RESULTS Univariate conditional logistic regression analysis found that cases were more likely to be men, to be of lower estimated social class, and to have had academic difficulties during their medical course, especially in the early years. Multivariable analysis showed that male sex (odds ratio 9.80, 95% confidence interval 2.43 to 39.44, P=0.001), lower social class (4.28, 1.52 to 12.09, P=0.006), and failure of early or preclinical examinations (5.47, 2.17 to 13.79, P<0.001) were independently associated with being a case. \n CONCLUSIONS This small study suggests that male sex, a lower socioeconomic background, and early academic difficulties at medical school could be risk factors for subsequent professional misconduct. The findings are preliminary and should be interpreted with caution. Most doctors with risk factors will not come before the GMC's disciplinary panels.", "title": "Risk factors at medical school for subsequent professional misconduct: multicentre retrospective case-control study" }, { "docid": "84580585", "text": "This volume and its companion, Volume 350, are specifically designed to meet the needs of graduate students and postdoctoral students as well as researchers, by providing all the up-to-date methods necessary to study genes in yeast. Procedures are included that enable newcomers to set up a yeast laboratory and to master basic manipulations. Relevant background and reference information given for procedures can be used as a guide to developing protocols in a number of disciplines. Specific topics addressed in this book include cytology, biochemistry, cell fractionation, and cell biology.", "title": "Guide to yeast genetics and molecular biology" }, { "docid": "31543713", "text": "The recent development of microarray technology has led statisticians and bioinformaticians to develop new statistical methodologies for comparing different biological samples. The objective is to identify a small number of differentially expressed genes from among thousands. In quantitative proteomics, analysis of protein expression using two-dimensional gel electrophoresis shows some similarities with transcriptomic studies. Thus, the goal of this study was to evaluate different data analysis methodologies widely used in array analysis using different proteomic data sets of hundreds of proteins. Even with few replications, the significance analysis of microarrays method appeared to be more powerful than the Student's t test in truly declaring differentially expressed proteins. This procedure will avoid wasting time due to false positives and losing information with false negatives.", "title": "Data analysis methods for detection of differential protein expression in two-dimensional gel electrophoresis." }, { "docid": "34818263", "text": "As time passes, the AIDS pandemic continues to spike, affecting an estimated 38.6 million people worldwide. In response, a satellite health clinic is being d esigned by two Cal Poly students to serve the Maasai people living in the Kajiado district in Southern Kenya. The Maasai have traditionally lived as pastoralists, surviving off of their cattle with which they share their water, increasing the risk for contamination. However, as the population of Kenya increases, the land the Maasai have traditionally used for grazing is shrink­ ing. For this reason, some have turned to farming to maintain their liveli­ hood. These factors have contributed to the desertification and deforestation of their region. As the lifestyle of the Maasai evolves, they rely more on maize than meat and dairy products for their nutrients. All of these changes have contributed to the evolution of the Maasai culture. We will address these changes in order to better understand the Maasai, as well as highlight pos­ sible further aid needed to support their survival.", "title": "Current Health and Environmental Status of the Maasai People in Sub-Saharan Africa" }, { "docid": "3413083", "text": "BACKGROUND Following widespread rollout of chlamydia testing to non-specialist and community settings in the UK, many individuals receive a chlamydia test without being offered comprehensive STI and HIV testing. We assess sexual behaviour among testers in different settings with a view to understanding their need for other STI diagnostic services. \n METHODS A probability sample survey of the British population undertaken 2010-2012 (the third National Survey of Sexual Attitudes and Lifestyles). We analysed weighted data on chlamydia testing (past year), including location of most recent test, and diagnoses (past 5 years) from individuals aged 16-44 years reporting at least one sexual partner in the past year (4992 women, 3406 men). \n RESULTS Of the 26.8% (95% CI 25.4% to 28.2%) of women and 16.7% (15.5% to 18.1%) of men reporting a chlamydia test in the past year, 28.4% of women and 41.2% of men had tested in genitourinary medicine (GUM), 41.1% and 20.7% of women and men respectively tested in general practice (GP) and the remainder tested in other non-GUM settings. Women tested outside GUM were more likely to be older, in a relationship and to live in rural areas. Individuals tested outside GUM reported fewer risk behaviours; nevertheless, 11.0% (8.6% to 14.1%) of women and 6.8% (3.9% to 11.6%) of men tested in GP and 13.2% (10.2% to 16.8%) and 9.6% (6.5% to 13.8%) of women and men tested in other non-GUM settings reported 'unsafe sex', defined as two or more partners and no condom use with any partner in the past year. Individuals treated for chlamydia outside GUM in the past 5 years were less likely to report an HIV test in that time frame (women: 54.5% (42.7% to 65.7%) vs 74.1% (65.9% to 80.9%) in GUM; men: 23.9% (12.7% to 40.5%) vs 65.8% (56.2% to 74.3%)). \n CONCLUSIONS Most chlamydia testing occurred in non-GUM settings, among populations reporting fewer risk behaviours. However, there is a need to provide pathways to comprehensive STI care to the sizeable minority at higher risk.", "title": "Patterns of chlamydia testing in different settings and implications for wider STI diagnosis and care: a probability sample survey of the British population" }, { "docid": "36033696", "text": "OBJECTIVE The purpose of this project was to educate inpatients with psychotic disorders, many of whom were taking second-generation antipsychotics, about lifestyle changes they can make to combat weight gain. \n METHOD All inpatients on a Veterans Affairs acute inpatient schizophrenia treatment unit were invited to a 30-minute, didactic presentation given by a medical student and a psychology student under the supervision of the primary investigator. The topics covered included the health benefits of maintaining an ideal body weight by selecting foods according to the USDA Food Pyramid, determining adequate food portions, choosing healthy meals outside the home, and beginning and adhering to an exercise program. Subjects completed a 13-item quiz concerning their knowledge of food and nutrition before and after the presentation to determine its efficacy in teaching patients the material. \n RESULTS Fifty patients completed both the pre- and post-presentation tests. The mean percentage of correct answers on the pre-test was 85.6%, which rose to 89.3% on the post-test. This difference of 3.7% was statistically significant (t = 2.43, df = 49, p < 0.02), and the mean percent of improvement was 6.1%. \n CONCLUSIONS This study demonstrates that psychotic individuals are able to benefit from educational presentations about nutrition and a healthy lifestyle. A statistically significant improvement in test scores suggests that subjects gained an understanding of basic concepts related to food choices and fitness.", "title": "A wellness class for inpatients with psychotic disorders." }, { "docid": "45027320", "text": "BACKGROUND The aim of this study was to examine the clustering of four major lifestyle risk factors (smoking, heavy drinking, lack of fruit and vegetables consumption, and lack of physical activity), and to examine the variation across different socio-demographic groups in the English adult population. \n METHODS The study population was derived from the 2003 Health Survey for England (n=11,492). Clustering was examined by comparing the observed and expected prevalence of the different possible combinations. A multinomial multilevel regression model was conducted to examine the socio-demographic variation in the clustering of the four risk factors. \n RESULTS The study found that, when using British health recommendations, a majority of the English population have multiple lifestyle risk factors at the same time. Clustering was found at both ends of the lifestyle spectrum and was more pronounced for women than for men. Overall, multiple risk factors were more prevalent among men, lower social class households, singles, and people who are economically inactive, but less prevalent among home owners and older age groups. \n CONCLUSIONS The clustering of multiple risk factors provides support for multiple-behavior interventions as opposed to single-behavior interventions.", "title": "The prevalence and clustering of four major lifestyle risk factors in an English adult population." }, { "docid": "13445579", "text": "BACKGROUND AND PURPOSE IAs are found in 2.3% of adults; the mean age at detection is 52 years. Prevalence is <0.5% in young adults. Early studies suggest that 10%-50% of patients with aortic coarctation have IAs. Screening recommendations are variable. We sought to examine the prevalence of IAs through screening with MRA. MATERIALS AND METHODS Consecutive patients older than 16 years of age with coarctation undergoing brain MRA between May 1999 and October 2007 were included. MRA was performed by using a 1.5T scanner with a 3D time-of-flight protocol; simultaneous MR imaging was performed of the heart and aorta. Cerebral MRAs were double-reported by a neuroradiologist. Statistics are described as mean ± SD and median ± range. Continuous variables were compared by using Student t tests and Mann-Whitney U tests (categoric variables, by using the Fisher exact test). \n RESULTS One hundred seventeen MRAs were double-reported. The median age was 29 ± 11 years (range, 16-59 years). IAs were found in 12 patients (10.3%). The mean diameter of IAs was 3.9 mm (range, 2.0-8.0 mm). Patients with aneurysms were older (median, 37 years; range, 16-50 years) than those without (median, 23 years; range, 16-59 years; Z = -2.01, P = .04). Hypertension was more common in those with IAs (IA 83% versus no IA 43%, P = .01). There was no association between ascending aortopathy, bicuspid aortic valves, and IAs. \n CONCLUSIONS Patients with coarctation have a higher prevalence of IAs, occurring at an earlier age than in population studies. Whether routine screening is appropriate for this group of patients is unclear. Hypertension is likely to be an important pathophysiologic factor.", "title": "Results of screening for intracranial aneurysms in patients with coarctation of the aorta." }, { "docid": "13900610", "text": "BACKGROUND Self-harm and suicide are common in prisoners, yet robust information on the full extent and characteristics of people at risk of self-harm is scant. Furthermore, understanding how frequently self-harm is followed by suicide, and in which prisoners this progression is most likely to happen, is important. We did a case-control study of all prisoners in England and Wales to ascertain the prevalence of self-harm in this population, associated risk factors, clustering effects, and risk of subsequent suicide after self-harm. \n METHODS Records of self-harm incidents in all prisons in England and Wales were gathered routinely between January, 2004, and December, 2009. We did a case-control comparison of prisoners who self-harmed and those who did not between January, 2006, and December, 2009. We also used a Bayesian approach to look at clustering of people who self-harmed. Prisoners who self-harmed and subsequently died by suicide in prison were compared with other inmates who self-harmed. \n FINDINGS 139,195 self-harm incidents were recorded in 26,510 individual prisoners between 2004 and 2009; 5-6% of male prisoners and 20-24% of female inmates self-harmed every year. Self-harm rates were more than ten times higher in female prisoners than in male inmates. Repetition of self-harm was common, particularly in women and teenage girls, in whom a subgroup of 102 prisoners accounted for 17,307 episodes. In both sexes, self-harm was associated with younger age, white ethnic origin, prison type, and a life sentence or being unsentenced; in female inmates, committing a violent offence against an individual was also a factor. Substantial evidence was noted of clustering in time and location of prisoners who self-harmed (adjusted intra-class correlation 0·15, 95% CI 0·11-0·18). 109 subsequent suicides in prison were reported in individuals who self-harmed; the risk was higher in those who self-harmed than in the general prison population, and more than half the deaths occurred within a month of self-harm. Risk factors for suicide after self-harm in male prisoners were older age and a previous self-harm incident of high or moderate lethality; in female inmates, a history of more than five self-harm incidents within a year was associated with subsequent suicide. \n INTERPRETATION The burden of self-harm in prisoners is substantial, particularly in women. Self-harm in prison is associated with subsequent suicide in this setting. Prevention and treatment of self-harm in prisoners is an essential component of suicide prevention in prisons. \n FUNDING Wellcome Trust, National Institute for Health Research, National Offender Management Service, and Department of Health.", "title": "Self-harm in prisons in England and Wales: an epidemiological study of prevalence, risk factors, clustering, and subsequent suicide" }, { "docid": "21641088", "text": "Obesity is a multifactorial disease with a marked genetic component. The situation is further complicated by the heterogeneity of obesity demonstrated by the topographical distribution of body fat, e.g. upper body (central) and lower body (gluteal) obesity. Furthermore, the distribution of fat shows a stronger heritable tendency compared with total body fat. Central obesity is characterized by hyperinsulinaemia and insulin resistance, a feature in common with non-insulin dependent diabetes mellitus, hypertension and atherosclerosis. In order to study the molecular genetics of central obesity we have examined 56 severely obese (mean body mass index 40), unrelated British Caucasoid young non-diabetic women for associations of restriction fragment length polymorphism of candidate genes with anthropometric measurements and indices of insulin secretion and resistance. The candidate genes examined were insulin receptor, insulin sensitive glucose transporter and insulin. An association of the class 3 allele of the hypervariable region in the 5' flanking region of the insulin gene was found with upper segment obesity (P = 0.005). Furthermore, the class 3 allele was also associated with fasting hyperinsulinaemia (P = 0.01), stimulated insulin secretion (P = 0.01) and insulin resistance as calculated from the homeostatic model of assessment (HOMA; P = 0.008). No such associations were found with the other candidate genes studied. This data suggests that polymorphisms in the 5' flanking region of the insulin gene may affect expression of the gene and thereby modulate insulin production in severely obese female subjects.", "title": "Central obesity and hyperinsulinaemia in women are associated with polymorphism in the 5' flanking region of the human insulin gene." }, { "docid": "9211173", "text": "BACKGROUND Ovarian clear-cell and endometrioid carcinomas may arise from endometriosis, but the molecular events involved in this transformation have not been described. \n METHODS We sequenced the whole transcriptomes of 18 ovarian clear-cell carcinomas and 1 ovarian clear-cell carcinoma cell line and found somatic mutations in ARID1A (the AT-rich interactive domain 1A [SWI-like] gene) in 6 of the samples. ARID1A encodes BAF250a, a key component of the SWI–SNF chromatin remodeling complex. We sequenced ARID1A in an additional 210 ovarian carcinomas and a second ovarian clear-cell carcinoma cell line and measured BAF250a expression by means of immunohistochemical analysis in an additional 455 ovarian carcinomas. \n RESULTS ARID1A mutations were seen in 55 of 119 ovarian clear-cell carcinomas (46%), 10 of 33 endometrioid carcinomas (30%), and none of the 76 high-grade serous ovarian carcinomas. Seventeen carcinomas had two somatic mutations each. Loss of the BAF250a protein correlated strongly with the ovarian clear-cell carcinoma and endometrioid carcinoma subtypes and the presence of ARID1A mutations. In two patients, ARID1A mutations and loss of BAF250a expression were evident in the tumor and contiguous atypical endometriosis but not in distant endometriotic lesions. \n CONCLUSIONS These data implicate ARID1A as a tumor-suppressor gene frequently disrupted in ovarian clear-cell and endometrioid carcinomas. Since ARID1A mutation and loss of BAF250a can be seen in the preneoplastic lesions, we speculate that this is an early event in the transformation of endometriosis into cancer. (Funded by the British Columbia Cancer Foundation and the Vancouver General Hospital–University of British Columbia Hospital Foundation.).", "title": "ARID1A mutations in endometriosis-associated ovarian carcinomas." }, { "docid": "12561083", "text": "BACKGROUND Several studies have demonstrated that women with nonobstructive coronary disease have a high rate of subsequent investigations, rehospitalizations for recurrent chest pain, and repeat coronary angiography. The sex specificity of this finding is unclear. We therefore undertook an evaluation of sex differences in rehospitalization for acute coronary syndrome (ACS) or chest pain in patients with \"angiographically normal\" coronaries. \n METHODS A retrospective cohort study using prospectively collected angiographic and clinical data on all patients in British Columbia, Canada, presenting for their first cardiac catheterization with suspected ischemic heart disease but angiographically normal coronaries. \n RESULTS Among 32,856 patients, 7.1% of men versus 23.3% of women were angiographically normal (P < .001). Among angiographically normal patients, women were older and more likely to present with hypertension, prior stroke, chronic obstructive pulmonary disease, and peripheral vascular disease than men, but Canadian Cardiovascular Society class of angina did not vary by sex. Within 1 year, 1.0% died, (19 women, 18 men, P = .27) and 0.6% had a stroke (13 women, 9 men, P = .91). Readmission to hospital for ACS or chest pain requiring catheterization was significantly higher in women compared to men (adjusted OR 4.06; 95% CI 1.15-14.31). \n CONCLUSIONS In a contemporary, population-based cohort presenting for cardiac catheterization for suspected ischemia, women with angiographically normal coronaries were >4 times more likely to be readmitted to hospital for ACS/chest pain within 180 days compared to men. The observed sex difference has important social and economic implications and suggests that traditional diagnostic methods may not be optimal for women.", "title": "Angina with \"normal\" coronary arteries: sex differences in outcomes." } ]

[ { "docid": "16855829", "text": "Bullying is still prevalent in schools and is clearly stressful for victims. 1 2 It may also have undesirable consequences for bullies, with antisocial behaviour persisting into adulthood. Victims are generally reported to be weaker than the bullies. 2 3 This would suggest that very short pupils are more likely to be victims and less likely to be the aggressors. The Wessex growth study allowed us to examine the prevalence of bullying, as experienced or perpetrated by pupils of different heights. Ninety two short normal adolescents who had been below the third centile for height at school entry4 and 117 controls matched for age and sex completed a bullying questionnaire, derived from work by Whitney and Smith.5 There were no refusals or any significant differences in sex or social class between the groups. Mean age (range) was 14.7 (13.4-15.7) years. Mean height SD scores were: short pupils −1.90 (−3.53 to −0.01), controls 0.31 (−1.41 …", "title": "Bullying in school: are short pupils at risk? Questionnaire study in a cohort." } ]

[ { "docid": "2867345", "text": "BACKGROUND A sexual dimorphism exists in the incidence and prevalence of coronary artery disease--men are more commonly affected than are age-matched women. We explored the role of the Y chromosome in coronary artery disease in the context of this sexual inequity. \n METHODS We genotyped 11 markers of the male-specific region of the Y chromosome in 3233 biologically unrelated British men from three cohorts: the British Heart Foundation Family Heart Study (BHF-FHS), West of Scotland Coronary Prevention Study (WOSCOPS), and Cardiogenics Study. On the basis of this information, each Y chromosome was tracked back into one of 13 ancient lineages defined as haplogroups. We then examined associations between common Y chromosome haplogroups and the risk of coronary artery disease in cross-sectional BHF-FHS and prospective WOSCOPS. Finally, we undertook functional analysis of Y chromosome effects on monocyte and macrophage transcriptome in British men from the Cardiogenics Study. \n FINDINGS Of nine haplogroups identified, two (R1b1b2 and I) accounted for roughly 90% of the Y chromosome variants among British men. Carriers of haplogroup I had about a 50% higher age-adjusted risk of coronary artery disease than did men with other Y chromosome lineages in BHF-FHS (odds ratio 1·75, 95% CI 1·20-2·54, p=0·004), WOSCOPS (1·45, 1·08-1·95, p=0·012), and joint analysis of both populations (1·56, 1·24-1·97, p=0·0002). The association between haplogroup I and increased risk of coronary artery disease was independent of traditional cardiovascular and socioeconomic risk factors. Analysis of macrophage transcriptome in the Cardiogenics Study revealed that 19 molecular pathways showing strong differential expression between men with haplogroup I and other lineages of the Y chromosome were interconnected by common genes related to inflammation and immunity, and that some of them have a strong relevance to atherosclerosis. \n INTERPRETATION The human Y chromosome is associated with risk of coronary artery disease in men of European ancestry, possibly through interactions of immunity and inflammation. \n FUNDING British Heart Foundation; UK National Institute for Health Research; LEW Carty Charitable Fund; National Health and Medical Research Council of Australia; European Union 6th Framework Programme; Wellcome Trust.", "title": "Inheritance of coronary artery disease in men: an analysis of the role of the Y chromosome" }, { "docid": "12789595", "text": "It is becoming “a truth universally acknowledged” that the education of undergraduate medical students will be enhanced through the use of computer assisted learning. Access to the wide range of online options illustrated in the figure must surely make learning more exciting, effective, and likely to be retained. This assumption is potentially but by no means inevitably correct. ### Box 1: Why fund computer assisted learning? Computer assisted learning is inevitable —Individual lecturers and departments are already beginning to introduce a wide range of computer based applications, sometimes in a haphazard way. Planned and coordinated development is better than indiscriminate expansion It is convenient and flexible —Courses supported by computer assisted learning applications may require fewer face to face lectures and seminars and place fewer geographical and temporal constraints on staff and students. Students at peripheral hospitals or primary care centres may benefit in particular Unique presentational benefits —Computer presentation is particularly suited to subjects that are visually intensive, detail oriented, and difficult to conceptualise, such as complex biochemical processes or microscopic images.1 Furthermore, “virtual” cases may reduce the need to use animal or human tissue in learning Personalised learning —Each learner can progress at his or her preferred pace. They can repeat, interrupt, and resume at will, which may have particular advantages for weaker students Economies of scale —Once an application has been set up, the incremental cost of offering it to additional students is relatively small Competitive advantage —Potential applicants may use the quality of information technology to discriminate between medical schools. A “leading edge” virtual campus is likely to attract good students Achieves the ultimate goal of higher education —The goal is to link people into learning communities. Computer applications, especially the internet and world wide web, are an extremely efficient way of doing this2 Expands pedagogical horizons —The most controversial argument for … RETURN TO TEXT", "title": "Computer assisted learning in undergraduate medical education." }, { "docid": "17374970", "text": "AIM To determine attrition and predictors of academic success among medical students at University of Split, Croatia. \n METHODS We analysed academic records of 2054 students enrolled during 1979-2008 period. \n RESULTS We found that 26% (533/2054) of enrolled students did not graduate. The most common reasons for attrition were 'personal' (36.4%), transfer to another medical school (35.6%), and dismissal due to unsatisfactory academic record (21.2%). Grade point average (GPA) and study duration of attrition students were significantly associated with parental education. There were 1126 graduates, 395 men and 731 women. Their average graduation GPA was 3.67±0.53 and study duration 7.6±2.44 years. During 5-year curriculum only 6.4% (42/654) of students graduated in time, and 55% (240/472) of students graduated in time after curriculum was extended to 6 years. Variables predicting whether a student will graduate or not were high school grades, entrance exam score and year of enrollment. Significant predictors of graduation grades were high school grades and entrance exam score. Entrance exam score predicted length of studying. \n CONCLUSION Preadmission academic qualifications and year of enrollment predict academic success in medical school. More attention should be devoted to high attrition.", "title": "Predictors of Attrition and Academic Success of Medical Students: A 30-Year Retrospective Study" }, { "docid": "24159217", "text": "CONTEXT No randomized controlled studies have been conducted to date on the effectiveness of psychological interventions for children with symptoms of posttraumatic stress disorder (PTSD) that has resulted from personally witnessing or being personally exposed to violence. \n OBJECTIVE To evaluate the effectiveness of a collaboratively designed school-based intervention for reducing children's symptoms of PTSD and depression that has resulted from exposure to violence. \n DESIGN A randomized controlled trial conducted during the 2001-2002 academic year. \n SETTING AND PARTICIPANTS Sixth-grade students at 2 large middle schools in Los Angeles who reported exposure to violence and had clinical levels of symptoms of PTSD. \n INTERVENTION Students were randomly assigned to a 10-session standardized cognitive-behavioral therapy (the Cognitive-Behavioral Intervention for Trauma in Schools) early intervention group (n = 61) or to a wait-list delayed intervention comparison group (n = 65) conducted by trained school mental health clinicians. \n MAIN OUTCOME MEASURES Students were assessed before the intervention and 3 months after the intervention on measures assessing child-reported symptoms of PTSD (Child PTSD Symptom Scale; range, 0-51 points) and depression (Child Depression Inventory; range, 0-52 points), parent-reported psychosocial dysfunction (Pediatric Symptom Checklist; range, 0-70 points), and teacher-reported classroom problems using the Teacher-Child Rating Scale (acting out, shyness/anxiousness, and learning problems; range of subscales, 6-30 points). \n RESULTS Compared with the wait-list delayed intervention group (no intervention), after 3 months of intervention students who were randomly assigned to the early intervention group had significantly lower scores on symptoms of PTSD (8.9 vs 15.5, adjusted mean difference, - 7.0; 95% confidence interval [CI], - 10.8 to - 3.2), depression (9.4 vs 12.7, adjusted mean difference, - 3.4; 95% CI, - 6.5 to - 0.4), and psychosocial dysfunction (12.5 vs 16.5, adjusted mean difference, - 6.4; 95% CI, -10.4 to -2.3). Adjusted mean differences between the 2 groups at 3 months did not show significant differences for teacher-reported classroom problems in acting out (-1.0; 95% CI, -2.5 to 0.5), shyness/anxiousness (0.1; 95% CI, -1.5 to 1.7), and learning (-1.1, 95% CI, -2.9 to 0.8). At 6 months, after both groups had received the intervention, the differences between the 2 groups were not significantly different for symptoms of PTSD and depression; showed similar ratings for psychosocial function; and teachers did not report significant differences in classroom behaviors. \n CONCLUSION A standardized 10-session cognitive-behavioral group intervention can significantly decrease symptoms of PTSD and depression in students who are exposed to violence and can be effectively delivered on school campuses by trained school-based mental health clinicians.", "title": "A mental health intervention for schoolchildren exposed to violence: a randomized controlled trial." }, { "docid": "24510595", "text": "PURPOSE Patients with daily or near-daily headaches are commonly seen in neurology practices and in headache subspecialty centers, but there is little information on the prevalence of this condition in the general population. We present the first US-based study describing the prevalence and characteristics of frequent headache in the general population. \n METHODS In Baltimore County, Maryland, 13 343 individuals 18 to 65 years of age were selected by random-digit dialing and interviewed by telephone about their headaches. Subjects reporting 180 or more headaches per year were classified as having frequent headache. Three mutually exclusive subtypes of frequent headache were identified: frequent headache with migrainous features, chronic tension-type headache, and unclassified frequent headache. \n RESULTS The overall prevalence of frequent headache was 4.1% (5.0% female, 2.8% male; 1.8:1 female to male ratio). Frequent headache was 33% more common in Caucasians (4.4%) than in African Americans (3.3%). In both males and females, prevalence was highest in the lowest educational category. Among frequent headache sufferers, more than half (52% female, 56% male) met criteria for chronic tension-type headache, almost one third (33% female, 25% male) met criteria for frequent headache with migrainous features, and the remainder (15% female, 19% male) were unclassified. Overall, 30% of female and 25% of male frequent headache sufferers met International Headache Society (IHS) criteria for migraine (with or without aura). \n CONCLUSIONS Frequent headache is common in the general population and is more prevalent in Caucasians and in those with less than a high school education. Chronic tension-type headache is more common than frequent headache with migrainous features, though the latter is more disabling. Although more common in females than males, the female preponderance of frequent headache is less marked than in migraine. The sex ratio varies by frequent headache subtype.", "title": "Prevalence of frequent headache in a population sample." }, { "docid": "36558211", "text": "OBJECTIVES To explore the different characteristics of high and low fat consumers, in particular their macronutrient intake and body mass index. \n DESIGN Reanalysis of data from the Dietary and Nutritional Survey of British Adults. Comparisons were made between groups defined as high and low fat consumers on the basis of 7-day weighed food records considered to be valid for energy intake. Individuals were classified in two ways according to the percentage energy from fat (FAT%) and the absolute amount of fat consumed (FATg). The criteria for classification of the high FAT% being > 45% (high fat) and < or = 35% (low fat). For the FATg group the threshold for the high fat group was > 138 g/day (men) and > 102 g/day (women), and for the low fat group < 85 g/day (men) and < 70 g/day (women). \n SETTING Dietary data was collected from private households in Great Britain between 1986 and 1987. SUBJECTS From the total population of 2197, individuals who were slimming, ill or had an EI: BMR of < 1.2 were excluded in order to use data which was most likely to represent habitual energy intakes. From the remaining 1240 subjects, 10.8% of this sample (6.1% of the total population) were classified as low fat consumers (76 men and 58 women) and 15.4% high fat (8.7% of the total population, 93 men and 98 women). \n MAIN OUTCOME MEASURES Macronutrient consumption and body mass index (BMI). \n RESULTS 30% of the subjects changed fat group classification when the criteria of defining high and low fat groups altered from FAT% to FATg. Nutrient intakes differed according to definition of the groups. The high fat FATg group ate significantly more of all nutrients than the low fat FATg group. However, this was not seen for the FAT% analysis, with the high fat group eating more fat and less carbohydrate. The average BMI tended to be higher in the high fat than the low fat groups, particularly in the FATg analysis. However, the high fat group contained a wide range of BMIs. Further exploration of BMI in the high fat groups, showed that age (an 11-year difference) was the only variable to distinguish individuals in the top and bottom quartiles of BMI. \n CONCLUSIONS High and low fat consumers differ according to a number of variables, and this is affected by how these groups are defined (FAT% or FATg). High fat consumers tend to have a higher BMI than low fat consumers, but not all high fat consumers are overweight or obese.", "title": "High and low fat consumers, their macronutrient intake and body mass index: further analysis of the National Diet and Nutrition Survey of British Adults." }, { "docid": "2295434", "text": "myfood24 Is an online 24-h dietary assessment tool developed for use among British adolescents and adults. Limited information is available regarding the validity of using new technology in assessing nutritional intake among adolescents. Thus, a relative validation of myfood24 against a face-to-face interviewer-administered 24-h multiple-pass recall (MPR) was conducted among seventy-five British adolescents aged 11-18 years. Participants were asked to complete myfood24 and an interviewer-administered MPR on the same day for 2 non-consecutive days at school. Total energy intake (EI) and nutrients recorded by the two methods were compared using intraclass correlation coefficients (ICC), Bland-Altman plots (using between and within-individual information) and weighted κ to assess the agreement. Energy, macronutrients and other reported nutrients from myfood24 demonstrated strong agreement with the interview MPR data, and ICC ranged from 0·46 for Na to 0·88 for EI. There was no significant bias between the two methods for EI, macronutrients and most reported nutrients. The mean difference between myfood24 and the interviewer-administered MPR for EI was -230 kJ (-55 kcal) (95 % CI -490, 30 kJ (-117, 7 kcal); P=0·4) with limits of agreement ranging between 39 % (3336 kJ (-797 kcal)) lower and 34 % (2874 kJ (687 kcal)) higher than the interviewer-administered MPR. There was good agreement in terms of classifying adolescents into tertiles of EI (κ w =0·64). The agreement between day 1 and day 2 was as good for myfood24 as for the interviewer-administered MPR, reflecting the reliability of myfood24. myfood24 Has the potential to collect dietary data of comparable quality with that of an interviewer-administered MPR.", "title": "Agreement between an online dietary assessment tool (myfood24) and an interviewer-administered 24-h dietary recall in British adolescents aged 11-18 years." }, { "docid": "6710713", "text": "OBJECTIVE To determine whether there are risk factors in a doctor's time at medical school that are associated with subsequent professional misconduct. \n DESIGN Matched case-control study. Setting Records from medical schools and the General Medical Council (GMC). \n PARTICIPANTS 59 doctors who had graduated from any one of eight medical schools in the United Kingdom in 1958-97 and had a proved finding of serious professional misconduct in GMC proceedings in 1999-2004 (cases); 236 controls (four for each case) were selected by systematic sampling from matching graduation cohorts. Case-control status was revealed by the GMC after completion of data entry. \n MAIN OUTCOME MEASURE Odds ratios for being a \"case,\" with multivariable conditional logistic regression of potential risk factors including pre-admission characteristics and progress during the course. These data were obtained from anonymised copies of the students' progress files held by their original medical schools. \n RESULTS Univariate conditional logistic regression analysis found that cases were more likely to be men, to be of lower estimated social class, and to have had academic difficulties during their medical course, especially in the early years. Multivariable analysis showed that male sex (odds ratio 9.80, 95% confidence interval 2.43 to 39.44, P=0.001), lower social class (4.28, 1.52 to 12.09, P=0.006), and failure of early or preclinical examinations (5.47, 2.17 to 13.79, P<0.001) were independently associated with being a case. \n CONCLUSIONS This small study suggests that male sex, a lower socioeconomic background, and early academic difficulties at medical school could be risk factors for subsequent professional misconduct. The findings are preliminary and should be interpreted with caution. Most doctors with risk factors will not come before the GMC's disciplinary panels.", "title": "Risk factors at medical school for subsequent professional misconduct: multicentre retrospective case-control study" }, { "docid": "84580585", "text": "This volume and its companion, Volume 350, are specifically designed to meet the needs of graduate students and postdoctoral students as well as researchers, by providing all the up-to-date methods necessary to study genes in yeast. Procedures are included that enable newcomers to set up a yeast laboratory and to master basic manipulations. Relevant background and reference information given for procedures can be used as a guide to developing protocols in a number of disciplines. Specific topics addressed in this book include cytology, biochemistry, cell fractionation, and cell biology.", "title": "Guide to yeast genetics and molecular biology" }, { "docid": "31543713", "text": "The recent development of microarray technology has led statisticians and bioinformaticians to develop new statistical methodologies for comparing different biological samples. The objective is to identify a small number of differentially expressed genes from among thousands. In quantitative proteomics, analysis of protein expression using two-dimensional gel electrophoresis shows some similarities with transcriptomic studies. Thus, the goal of this study was to evaluate different data analysis methodologies widely used in array analysis using different proteomic data sets of hundreds of proteins. Even with few replications, the significance analysis of microarrays method appeared to be more powerful than the Student's t test in truly declaring differentially expressed proteins. This procedure will avoid wasting time due to false positives and losing information with false negatives.", "title": "Data analysis methods for detection of differential protein expression in two-dimensional gel electrophoresis." }, { "docid": "34818263", "text": "As time passes, the AIDS pandemic continues to spike, affecting an estimated 38.6 million people worldwide. In response, a satellite health clinic is being d esigned by two Cal Poly students to serve the Maasai people living in the Kajiado district in Southern Kenya. The Maasai have traditionally lived as pastoralists, surviving off of their cattle with which they share their water, increasing the risk for contamination. However, as the population of Kenya increases, the land the Maasai have traditionally used for grazing is shrink­ ing. For this reason, some have turned to farming to maintain their liveli­ hood. These factors have contributed to the desertification and deforestation of their region. As the lifestyle of the Maasai evolves, they rely more on maize than meat and dairy products for their nutrients. All of these changes have contributed to the evolution of the Maasai culture. We will address these changes in order to better understand the Maasai, as well as highlight pos­ sible further aid needed to support their survival.", "title": "Current Health and Environmental Status of the Maasai People in Sub-Saharan Africa" }, { "docid": "3413083", "text": "BACKGROUND Following widespread rollout of chlamydia testing to non-specialist and community settings in the UK, many individuals receive a chlamydia test without being offered comprehensive STI and HIV testing. We assess sexual behaviour among testers in different settings with a view to understanding their need for other STI diagnostic services. \n METHODS A probability sample survey of the British population undertaken 2010-2012 (the third National Survey of Sexual Attitudes and Lifestyles). We analysed weighted data on chlamydia testing (past year), including location of most recent test, and diagnoses (past 5 years) from individuals aged 16-44 years reporting at least one sexual partner in the past year (4992 women, 3406 men). \n RESULTS Of the 26.8% (95% CI 25.4% to 28.2%) of women and 16.7% (15.5% to 18.1%) of men reporting a chlamydia test in the past year, 28.4% of women and 41.2% of men had tested in genitourinary medicine (GUM), 41.1% and 20.7% of women and men respectively tested in general practice (GP) and the remainder tested in other non-GUM settings. Women tested outside GUM were more likely to be older, in a relationship and to live in rural areas. Individuals tested outside GUM reported fewer risk behaviours; nevertheless, 11.0% (8.6% to 14.1%) of women and 6.8% (3.9% to 11.6%) of men tested in GP and 13.2% (10.2% to 16.8%) and 9.6% (6.5% to 13.8%) of women and men tested in other non-GUM settings reported 'unsafe sex', defined as two or more partners and no condom use with any partner in the past year. Individuals treated for chlamydia outside GUM in the past 5 years were less likely to report an HIV test in that time frame (women: 54.5% (42.7% to 65.7%) vs 74.1% (65.9% to 80.9%) in GUM; men: 23.9% (12.7% to 40.5%) vs 65.8% (56.2% to 74.3%)). \n CONCLUSIONS Most chlamydia testing occurred in non-GUM settings, among populations reporting fewer risk behaviours. However, there is a need to provide pathways to comprehensive STI care to the sizeable minority at higher risk.", "title": "Patterns of chlamydia testing in different settings and implications for wider STI diagnosis and care: a probability sample survey of the British population" }, { "docid": "36033696", "text": "OBJECTIVE The purpose of this project was to educate inpatients with psychotic disorders, many of whom were taking second-generation antipsychotics, about lifestyle changes they can make to combat weight gain. \n METHOD All inpatients on a Veterans Affairs acute inpatient schizophrenia treatment unit were invited to a 30-minute, didactic presentation given by a medical student and a psychology student under the supervision of the primary investigator. The topics covered included the health benefits of maintaining an ideal body weight by selecting foods according to the USDA Food Pyramid, determining adequate food portions, choosing healthy meals outside the home, and beginning and adhering to an exercise program. Subjects completed a 13-item quiz concerning their knowledge of food and nutrition before and after the presentation to determine its efficacy in teaching patients the material. \n RESULTS Fifty patients completed both the pre- and post-presentation tests. The mean percentage of correct answers on the pre-test was 85.6%, which rose to 89.3% on the post-test. This difference of 3.7% was statistically significant (t = 2.43, df = 49, p < 0.02), and the mean percent of improvement was 6.1%. \n CONCLUSIONS This study demonstrates that psychotic individuals are able to benefit from educational presentations about nutrition and a healthy lifestyle. A statistically significant improvement in test scores suggests that subjects gained an understanding of basic concepts related to food choices and fitness.", "title": "A wellness class for inpatients with psychotic disorders." }, { "docid": "45027320", "text": "BACKGROUND The aim of this study was to examine the clustering of four major lifestyle risk factors (smoking, heavy drinking, lack of fruit and vegetables consumption, and lack of physical activity), and to examine the variation across different socio-demographic groups in the English adult population. \n METHODS The study population was derived from the 2003 Health Survey for England (n=11,492). Clustering was examined by comparing the observed and expected prevalence of the different possible combinations. A multinomial multilevel regression model was conducted to examine the socio-demographic variation in the clustering of the four risk factors. \n RESULTS The study found that, when using British health recommendations, a majority of the English population have multiple lifestyle risk factors at the same time. Clustering was found at both ends of the lifestyle spectrum and was more pronounced for women than for men. Overall, multiple risk factors were more prevalent among men, lower social class households, singles, and people who are economically inactive, but less prevalent among home owners and older age groups. \n CONCLUSIONS The clustering of multiple risk factors provides support for multiple-behavior interventions as opposed to single-behavior interventions.", "title": "The prevalence and clustering of four major lifestyle risk factors in an English adult population." }, { "docid": "13445579", "text": "BACKGROUND AND PURPOSE IAs are found in 2.3% of adults; the mean age at detection is 52 years. Prevalence is <0.5% in young adults. Early studies suggest that 10%-50% of patients with aortic coarctation have IAs. Screening recommendations are variable. We sought to examine the prevalence of IAs through screening with MRA. MATERIALS AND METHODS Consecutive patients older than 16 years of age with coarctation undergoing brain MRA between May 1999 and October 2007 were included. MRA was performed by using a 1.5T scanner with a 3D time-of-flight protocol; simultaneous MR imaging was performed of the heart and aorta. Cerebral MRAs were double-reported by a neuroradiologist. Statistics are described as mean ± SD and median ± range. Continuous variables were compared by using Student t tests and Mann-Whitney U tests (categoric variables, by using the Fisher exact test). \n RESULTS One hundred seventeen MRAs were double-reported. The median age was 29 ± 11 years (range, 16-59 years). IAs were found in 12 patients (10.3%). The mean diameter of IAs was 3.9 mm (range, 2.0-8.0 mm). Patients with aneurysms were older (median, 37 years; range, 16-50 years) than those without (median, 23 years; range, 16-59 years; Z = -2.01, P = .04). Hypertension was more common in those with IAs (IA 83% versus no IA 43%, P = .01). There was no association between ascending aortopathy, bicuspid aortic valves, and IAs. \n CONCLUSIONS Patients with coarctation have a higher prevalence of IAs, occurring at an earlier age than in population studies. Whether routine screening is appropriate for this group of patients is unclear. Hypertension is likely to be an important pathophysiologic factor.", "title": "Results of screening for intracranial aneurysms in patients with coarctation of the aorta." }, { "docid": "13900610", "text": "BACKGROUND Self-harm and suicide are common in prisoners, yet robust information on the full extent and characteristics of people at risk of self-harm is scant. Furthermore, understanding how frequently self-harm is followed by suicide, and in which prisoners this progression is most likely to happen, is important. We did a case-control study of all prisoners in England and Wales to ascertain the prevalence of self-harm in this population, associated risk factors, clustering effects, and risk of subsequent suicide after self-harm. \n METHODS Records of self-harm incidents in all prisons in England and Wales were gathered routinely between January, 2004, and December, 2009. We did a case-control comparison of prisoners who self-harmed and those who did not between January, 2006, and December, 2009. We also used a Bayesian approach to look at clustering of people who self-harmed. Prisoners who self-harmed and subsequently died by suicide in prison were compared with other inmates who self-harmed. \n FINDINGS 139,195 self-harm incidents were recorded in 26,510 individual prisoners between 2004 and 2009; 5-6% of male prisoners and 20-24% of female inmates self-harmed every year. Self-harm rates were more than ten times higher in female prisoners than in male inmates. Repetition of self-harm was common, particularly in women and teenage girls, in whom a subgroup of 102 prisoners accounted for 17,307 episodes. In both sexes, self-harm was associated with younger age, white ethnic origin, prison type, and a life sentence or being unsentenced; in female inmates, committing a violent offence against an individual was also a factor. Substantial evidence was noted of clustering in time and location of prisoners who self-harmed (adjusted intra-class correlation 0·15, 95% CI 0·11-0·18). 109 subsequent suicides in prison were reported in individuals who self-harmed; the risk was higher in those who self-harmed than in the general prison population, and more than half the deaths occurred within a month of self-harm. Risk factors for suicide after self-harm in male prisoners were older age and a previous self-harm incident of high or moderate lethality; in female inmates, a history of more than five self-harm incidents within a year was associated with subsequent suicide. \n INTERPRETATION The burden of self-harm in prisoners is substantial, particularly in women. Self-harm in prison is associated with subsequent suicide in this setting. Prevention and treatment of self-harm in prisoners is an essential component of suicide prevention in prisons. \n FUNDING Wellcome Trust, National Institute for Health Research, National Offender Management Service, and Department of Health.", "title": "Self-harm in prisons in England and Wales: an epidemiological study of prevalence, risk factors, clustering, and subsequent suicide" }, { "docid": "21641088", "text": "Obesity is a multifactorial disease with a marked genetic component. The situation is further complicated by the heterogeneity of obesity demonstrated by the topographical distribution of body fat, e.g. upper body (central) and lower body (gluteal) obesity. Furthermore, the distribution of fat shows a stronger heritable tendency compared with total body fat. Central obesity is characterized by hyperinsulinaemia and insulin resistance, a feature in common with non-insulin dependent diabetes mellitus, hypertension and atherosclerosis. In order to study the molecular genetics of central obesity we have examined 56 severely obese (mean body mass index 40), unrelated British Caucasoid young non-diabetic women for associations of restriction fragment length polymorphism of candidate genes with anthropometric measurements and indices of insulin secretion and resistance. The candidate genes examined were insulin receptor, insulin sensitive glucose transporter and insulin. An association of the class 3 allele of the hypervariable region in the 5' flanking region of the insulin gene was found with upper segment obesity (P = 0.005). Furthermore, the class 3 allele was also associated with fasting hyperinsulinaemia (P = 0.01), stimulated insulin secretion (P = 0.01) and insulin resistance as calculated from the homeostatic model of assessment (HOMA; P = 0.008). No such associations were found with the other candidate genes studied. This data suggests that polymorphisms in the 5' flanking region of the insulin gene may affect expression of the gene and thereby modulate insulin production in severely obese female subjects.", "title": "Central obesity and hyperinsulinaemia in women are associated with polymorphism in the 5' flanking region of the human insulin gene." }, { "docid": "9211173", "text": "BACKGROUND Ovarian clear-cell and endometrioid carcinomas may arise from endometriosis, but the molecular events involved in this transformation have not been described. \n METHODS We sequenced the whole transcriptomes of 18 ovarian clear-cell carcinomas and 1 ovarian clear-cell carcinoma cell line and found somatic mutations in ARID1A (the AT-rich interactive domain 1A [SWI-like] gene) in 6 of the samples. ARID1A encodes BAF250a, a key component of the SWI–SNF chromatin remodeling complex. We sequenced ARID1A in an additional 210 ovarian carcinomas and a second ovarian clear-cell carcinoma cell line and measured BAF250a expression by means of immunohistochemical analysis in an additional 455 ovarian carcinomas. \n RESULTS ARID1A mutations were seen in 55 of 119 ovarian clear-cell carcinomas (46%), 10 of 33 endometrioid carcinomas (30%), and none of the 76 high-grade serous ovarian carcinomas. Seventeen carcinomas had two somatic mutations each. Loss of the BAF250a protein correlated strongly with the ovarian clear-cell carcinoma and endometrioid carcinoma subtypes and the presence of ARID1A mutations. In two patients, ARID1A mutations and loss of BAF250a expression were evident in the tumor and contiguous atypical endometriosis but not in distant endometriotic lesions. \n CONCLUSIONS These data implicate ARID1A as a tumor-suppressor gene frequently disrupted in ovarian clear-cell and endometrioid carcinomas. Since ARID1A mutation and loss of BAF250a can be seen in the preneoplastic lesions, we speculate that this is an early event in the transformation of endometriosis into cancer. (Funded by the British Columbia Cancer Foundation and the Vancouver General Hospital–University of British Columbia Hospital Foundation.).", "title": "ARID1A mutations in endometriosis-associated ovarian carcinomas." }, { "docid": "12561083", "text": "BACKGROUND Several studies have demonstrated that women with nonobstructive coronary disease have a high rate of subsequent investigations, rehospitalizations for recurrent chest pain, and repeat coronary angiography. The sex specificity of this finding is unclear. We therefore undertook an evaluation of sex differences in rehospitalization for acute coronary syndrome (ACS) or chest pain in patients with \"angiographically normal\" coronaries. \n METHODS A retrospective cohort study using prospectively collected angiographic and clinical data on all patients in British Columbia, Canada, presenting for their first cardiac catheterization with suspected ischemic heart disease but angiographically normal coronaries. \n RESULTS Among 32,856 patients, 7.1% of men versus 23.3% of women were angiographically normal (P < .001). Among angiographically normal patients, women were older and more likely to present with hypertension, prior stroke, chronic obstructive pulmonary disease, and peripheral vascular disease than men, but Canadian Cardiovascular Society class of angina did not vary by sex. Within 1 year, 1.0% died, (19 women, 18 men, P = .27) and 0.6% had a stroke (13 women, 9 men, P = .91). Readmission to hospital for ACS or chest pain requiring catheterization was significantly higher in women compared to men (adjusted OR 4.06; 95% CI 1.15-14.31). \n CONCLUSIONS In a contemporary, population-based cohort presenting for cardiac catheterization for suspected ischemia, women with angiographically normal coronaries were >4 times more likely to be readmitted to hospital for ACS/chest pain within 180 days compared to men. The observed sex difference has important social and economic implications and suggests that traditional diagnostic methods may not be optimal for women.", "title": "Angina with \"normal\" coronary arteries: sex differences in outcomes." } ]

[ { "docid": "4421578", "text": "Characterization of human monoclonal antibodies is providing considerable insight into mechanisms of broad HIV-1 neutralization. Here we report an HIV-1 gp41 membrane-proximal external region (MPER)-specific antibody, named 10E8, which neutralizes ∼98% of tested viruses. An analysis of sera from 78 healthy HIV-1-infected donors demonstrated that 27% contained MPER-specific antibodies and 8% contained 10E8-like specificities. In contrast to other neutralizing MPER antibodies, 10E8 did not bind phospholipids, was not autoreactive, and bound cell-surface envelope. The structure of 10E8 in complex with the complete MPER revealed a site of vulnerability comprising a narrow stretch of highly conserved gp41-hydrophobic residues and a critical arginine or lysine just before the transmembrane region. Analysis of resistant HIV-1 variants confirmed the importance of these residues for neutralization. The highly conserved MPER is a target of potent, non-self-reactive neutralizing antibodies, suggesting that HIV-1 vaccines should aim to induce antibodies to this region of HIV-1 envelope glycoprotein.", "title": "Broad and potent neutralization of HIV-1 by a gp41-specific human antibody" } ]

[ { "docid": "3566945", "text": "Broadly neutralizing antibodies (bnAbs) to HIV-1 can evolve after years of an iterative process of virus escape and antibody adaptation that HIV-1 vaccine design seeks to mimic. To enable this, properties that render HIV-1 envelopes (Env) capable of eliciting bnAb responses need to be defined. Here, we followed the evolution of the V2 apex directed bnAb lineage VRC26 in the HIV-1 subtype C superinfected donor CAP256 to investigate the phenotypic changes of the virus populations circulating before and during the early phases of bnAb induction. Longitudinal viruses that evolved from the VRC26-resistant primary infecting (PI) virus, the VRC26-sensitive superinfecting (SU) virus and ensuing PI-SU recombinants revealed substantial phenotypic changes in Env, with a switch in Env properties coinciding with early resistance to VRC26. Decreased sensitivity of SU-like viruses to VRC26 was linked with reduced infectivity, altered entry kinetics and lower sensitivity to neutralization after CD4 attachment. VRC26 maintained neutralization activity against cell-associated CAP256 virus, indicating that escape through the cell-cell transmission route is not a dominant escape pathway. Reduced fitness of the early escape variants and sustained sensitivity in cell-cell transmission are both features that limit virus replication, thereby impeding rapid escape. This supports a scenario where VRC26 allowed only partial viral escape for a prolonged period, possibly increasing the time window for bnAb maturation. Collectively, our data highlight the phenotypic plasticity of the HIV-1 Env in evading bnAb pressure and the need to consider phenotypic traits when selecting and designing Env immunogens. Combinations of Env variants with differential phenotypic patterns and bnAb sensitivity, as we describe here for CAP256, may maximize the potential for inducing bnAb responses by vaccination.", "title": "Phenotypic deficits in the HIV-1 envelope are associated with the maturation of a V2-directed broadly neutralizing antibody lineage" }, { "docid": "5560962", "text": "Broadly neutralizing antibodies (bNAbs) to HIV-1 can prevent infection and are therefore of great importance for HIV-1 vaccine design. Notably, bNAbs are highly somatically mutated and generated by a fraction of HIV-1-infected individuals several years after infection. Antibodies typically accumulate mutations in the complementarity determining region (CDR) loops, which usually contact the antigen. The CDR loops are scaffolded by canonical framework regions (FWRs) that are both resistant to and less tolerant of mutations. Here, we report that in contrast to most antibodies, including those with limited HIV-1 neutralizing activity, most bNAbs require somatic mutations in their FWRs. Structural and functional analyses reveal that somatic mutations in FWR residues enhance breadth and potency by providing increased flexibility and/or direct antigen contact. Thus, in bNAbs, FWRs play an essential role beyond scaffolding the CDR loops and their unusual contribution to potency and breadth should be considered in HIV-1 vaccine design.", "title": "Somatic Mutations of the Immunoglobulin Framework Are Generally Required for Broad and Potent HIV-1 Neutralization" }, { "docid": "4373433", "text": "Broadly neutralizing antibodies against highly variable viral pathogens are much sought after to treat or protect against global circulating viruses. Here we probed the neutralizing antibody repertoires of four human immunodeficiency virus (HIV)-infected donors with remarkably broad and potent neutralizing responses and rescued 17 new monoclonal antibodies that neutralize broadly across clades. Many of the new monoclonal antibodies are almost tenfold more potent than the recently described PG9, PG16 and VRC01 broadly neutralizing monoclonal antibodies and 100-fold more potent than the original prototype HIV broadly neutralizing monoclonal antibodies. The monoclonal antibodies largely recapitulate the neutralization breadth found in the corresponding donor serum and many recognize novel epitopes on envelope (Env) glycoprotein gp120, illuminating new targets for vaccine design. Analysis of neutralization by the full complement of anti-HIV broadly neutralizing monoclonal antibodies now available reveals that certain combinations of antibodies should offer markedly more favourable coverage of the enormous diversity of global circulating viruses than others and these combinations might be sought in active or passive immunization regimes. Overall, the isolation of multiple HIV broadly neutralizing monoclonal antibodies from several donors that, in aggregate, provide broad coverage at low concentrations is a highly positive indicator for the eventual design of an effective antibody-based HIV vaccine.", "title": "Broad neutralization coverage of HIV by multiple highly potent antibodies" }, { "docid": "7177329", "text": "Neutralizing antibodies are likely to play a crucial part in a preventative HIV-1 vaccine. Although efforts to elicit broadly cross-neutralizing (BCN) antibodies by vaccination have been unsuccessful, a minority of individuals naturally develop these antibodies after many years of infection. How such antibodies arise, and the role of viral evolution in shaping these responses, is unknown. Here we show, in two HIV-1–infected individuals who developed BCN antibodies targeting the glycan at Asn332 on the gp120 envelope, that this glycan was absent on the initial infecting virus. However, this BCN epitope evolved within 6 months, through immune escape from earlier strain-specific antibodies that resulted in a shift of a glycan to position 332. Both viruses that lacked the glycan at amino acid 332 were resistant to the Asn332-dependent BCN monoclonal antibody PGT128 (ref. 8), whereas escaped variants that acquired this glycan were sensitive. Analysis of large sequence and neutralization data sets showed the 332 glycan to be significantly under-represented in transmitted subtype C viruses compared to chronic viruses, with the absence of this glycan corresponding with resistance to PGT128. These findings highlight the dynamic interplay between early antibodies and viral escape in driving the evolution of conserved BCN antibody epitopes.", "title": "Evolution of an HIV glycan–dependent broadly neutralizing antibody epitope through immune escape" }, { "docid": "13469921", "text": "Recent cross-sectional analyses of HIV-1+ plasmas have indicated that broadly cross-reactive neutralizing antibody responses are developed by 10%-30% of HIV-1+ subjects. The timing of the initial development of such anti-viral responses is unknown. It is also unknown whether the emergence of these responses coincides with the appearance of antibody specificities to a single or multiple regions of the viral envelope glycoprotein (Env). Here we analyzed the cross-neutralizing antibody responses in longitudinal plasmas collected soon after and up to seven years after HIV-1 infection. We find that anti-HIV-1 cross-neutralizing antibody responses first become evident on average at 2.5 years and, in rare cases, as early as 1 year following infection. If cross-neutralizing antibody responses do not develop during the first 2-3 years of infection, they most likely will not do so subsequently. Our results indicate a potential link between the development of cross-neutralizing antibody responses and specific activation markers on T cells, and with plasma viremia levels. The earliest cross-neutralizing antibody response targets a limited number of Env regions, primarily the CD4-binding site and epitopes that are not present on monomeric Env, but on the virion-associated trimeric Env form. In contrast, the neutralizing activities of plasmas from subjects that did not develop cross-neutralizing antibody responses target epitopes on monomeric gp120 other than the CD4-BS. Our study provides information that is not only relevant to better understanding the interaction of the human immune system with HIV but may guide the development of effective immunization protocols. Since antibodies to complex epitopes that are present on the virion-associated envelope spike appear to be key components of earliest cross-neutralizing activities of HIV-1+ plasmas, then emphasis should be made to elicit similar antibodies by vaccination.", "title": "Characteristics of the Earliest Cross-Neutralizing Antibody Response to HIV-1" }, { "docid": "8883846", "text": "The Global HIV Vaccine Enterprise convened a two-day workshop in May of 2007 to discuss humoral immune responses to HIV and approaches to design vaccines that induce viral neutralizing and other potentially protective antibody responses. The goals of this workshop were to identify key scientific issues, gaps, and opportunities that have emerged since the Enterprise Strategic Plan was first published in 2005 [1], and to make recommendations that Enterprise stakeholders can use to plan new activities. Most effective viral vaccines work, at least in part, by generating antibodies that inactivate or neutralize the invading virus, and the existing data strongly suggest that an optimally effective HIV-1 vaccine should elicit potent antiviral neutralizing antibodies. However, unlike acute viral pathogens, HIV-1 chronically replicates in the host and evades the antibody response. This immune evasion, along with the large genetic variation among HIV-1 strains worldwide, has posed major obstacles to vaccine development. Current HIV vaccine candidates do not elicit neutralizing antibodies against most circulating virus strains, and thus the induction of a protective antibody response remains a major priority for HIV-1 vaccine development. For an antibody-based HIV-1 vaccine, progress in vaccine design is generally gauged by in vitro assays that measure the ability of vaccine-induced antibodies to neutralize a broad spectrum of viral isolates representing the major genetic subtypes (clades) of HIV-1 [2]. Although it is not known what magnitude and breadth of neutralization will predict protection in vaccine recipients, it is clear that current vaccine immunogens elicit antibodies that neutralize only a minority of circulating isolates. Thus, much progress needs to be made in this area. Also, though virus neutralization is considered a critical benchmark for a vaccine, this may not be the only benchmark for predicting success with antibody-based HIV-1 vaccine immunogens. The main targets for neutralizing antibodies to HIV-1 are the surface gp120 and trans-membrane gp41 envelope glycoproteins (Env) that mediate receptor and coreceptor binding and the subsequent membrane fusion events that allow the virus to gain entry into cells [3]. Antibodies neutralize the virus by binding these viral spikes and blocking virus entry into susceptible cells, such as CD4+ T cells [4,5]. In order to chronically replicate in the host, the virus exploits several mechanisms to shield itself against antibody recognition, including a dense outer coating of sugar molecules (N-linked glycans) and the strategic positioning of cysteine–cysteine loop structures on the gp120 molecule [6–8]. These shielding mechanisms, although highly effective, have vulnerabilities imposed by fitness constraints. Information on the precise location and molecular structure of these vulnerable regions could be valuable for the rational design of improved vaccine immunogens. Participants in the workshop identified four areas that, if given proper attention, could provide key information that would bring the field closer to an effective antibody-based HIV-1 vaccine: (1) structure-assisted immunogen design, (2) role of Fc receptors and complement, (3) assay standardization and validation, and (4) immunoregulation of B cell responses.", "title": "Antibody-Based HIV-1 Vaccines: Recent Developments and Future Directions" }, { "docid": "23915841", "text": "The study of the evolution and specificities of neutralizing antibodies during the course of human immunodeficiency virus type 1 (HIV-1) infection may be important in the discovery of possible targets for vaccine design. In this study, we assessed the autologous and heterologous neutralization responses of 14 HIV-1 subtype C-infected individuals, using envelope clones obtained within the first 2 months postinfection. Our data show that potent but relatively strain-specific neutralizing antibodies develop within 3 to 12 months of HIV-1 infection. The magnitude of this response was associated with shorter V1-to-V5 envelope lengths and fewer glycosylation sites, particularly in the V1-V2 region. Anti-MPER antibodies were detected in 4 of 14 individuals within a year of infection, while antibodies to CD4-induced (CD4i) epitopes developed to high titers in 12 participants, in most cases before the development of autologous neutralizing antibodies. However, neither anti-MPER nor anti-CD4i antibody specificity conferred neutralization breadth. These data provide insights into the kinetics, potency, breadth, and epitope specificity of neutralizing antibody responses in acute HIV-1 subtype C infection.", "title": "Neutralizing antibody responses in acute human immunodeficiency virus type 1 subtype C infection." }, { "docid": "26038789", "text": "3BNC117 is a broad and potent neutralizing antibody to HIV-1 that targets the CD4 binding site on the viral envelope spike. When administered passively, this antibody can prevent infection in animal models and suppress viremia in HIV-1–infected individuals. Here we report that HIV-1 immunotherapy with a single injection of 3BNC117 affects host antibody responses in viremic individuals. In comparison to untreated controls that showed little change in their neutralizing activity over a 6-month period, 3BNC117 infusion significantly improved neutralizing responses to heterologous tier 2 viruses in nearly all study participants. We conclude that 3BNC117-mediated immunotherapy enhances host humoral immunity to HIV-1.", "title": "HIV-1 therapy with monoclonal antibody 3BNC117 elicits host immune responses against HIV-1" }, { "docid": "2601135", "text": "A recent study of plasma neutralization breadth in HIV-1 infected individuals at nine International AIDS Vaccine Initiative (IAVI) sites reported that viral load, HLA-A*03 genotype, and subtype C infection were strongly associated with the development of neutralization breadth. Here, we refine the findings of that study by analyzing the impact of the transmitted/founder (T/F) envelope (Env), early Env diversification, and autologous neutralization on the development of plasma neutralization breadth in 21 participants identified during recent infection at two of those sites: Kigali, Rwanda (n = 9) and Lusaka, Zambia (n = 12). Single-genome analysis of full-length T/F Env sequences revealed that all 21 individuals were infected with a highly homogeneous population of viral variants, which were categorized as subtype C (n = 12), A1 (n = 7), or recombinant AC (n = 2). An extensive amino acid sequence-based analysis of variable loop lengths and glycosylation patterns in the T/F Envs revealed that a lower ratio of NXS to NXT-encoded glycan motifs correlated with neutralization breadth. Further analysis comparing amino acid sequence changes, insertions/deletions, and glycan motif alterations between the T/F Env and autologous early Env variants revealed that extensive diversification focused in the V2, V4, and V5 regions of gp120, accompanied by contemporaneous viral escape, significantly favored the development of breadth. These results suggest that more efficient glycosylation of subtype A and C T/F Envs through fewer NXS-encoded glycan sites is more likely to elicit antibodies that can transition from autologous to heterologous neutralizing activity following exposure to gp120 diversification. This initiates an Env-antibody co-evolution cycle that increases neutralization breadth, and is further augmented over time by additional viral and host factors. These findings suggest that understanding how variation in the efficiency of site-specific glycosylation influences neutralizing antibody elicitation and targeting could advance the design of immunogens aimed at inducing antibodies that can transition from autologous to heterologous neutralizing activity.", "title": "Diversification in the HIV-1 Envelope Hyper-variable Domains V2, V4, and V5 and Higher Probability of Transmitted/Founder Envelope Glycosylation Favor the Development of Heterologous Neutralization Breadth" }, { "docid": "36962270", "text": "We have modified an Escherichia coli vector expressing 66-kDa HIV-1 reverse transcriptase (p66) so that it simultaneously expresses this and the pol-coded protease. The twin expression cassette yields high quantities of both reverse transcriptase and protease; however, under these conditions, 50% of the over-expressed p66 reverse transcriptase is processed, resulting in accumulation of large quantities of p66/p51 enzyme. Furthermore, addition of a poly(histidine) affinity label at the amino terminus of the reverse-transcriptase-coding sequence (His-p66) permits a simple, rapid purification of milligram quantities of either p66 or p66/p51 enzyme from a crude lysate by metal chelate affinity chromatography. Purified His-p66 and His-p66/His-p51 reverse transcriptase exhibit both reverse transcriptase and RNase H activity. Purification by metal chelate chromatography of a p66/p51 enzyme wherein only the p66 component is labelled strengthens the argument for the existence of a heterodimer.", "title": "Rapid purification of homodimer and heterodimer HIV-1 reverse transcriptase by metal chelate affinity chromatography." }, { "docid": "5835149", "text": "OBJECTIVE To determine the prevalence and risk factors for hepatitis C virus (HCV) infection in a cohort of homosexually active men, with particular reference to assessing sexual transmission. \n DESIGN Prevalence based on cross-sectional testing for HCV (c100 protein) antibody in a cohort using sera stored between 1984 and 1989, and assessment of risk factors using a case-control analysis based on questionnaire data from HCV positive and negative subjects. \n SUBJECTS/SETTING 1038 homosexually active men who were participating in a prospective study established to identify risk factors for AIDS. They had been recruited through private and public primary care and sexually transmissible disease (STD) services in central Sydney. \n MAIN OUTCOME MEASURES Prevalence of HCV antibody and its association with human immunodeficiency virus type 1 (HIV-1) infection and other STDs, number of sexual partners, sexual practices and recreational drug use. \n RESULTS Overall, 7.6% of subjects tested were seropositive for HCV antibody. In univariate analysis, HCV infection was significantly associated with injecting drug use (IDU) (OR = 8.18, p < 0.0001) and HIV infection (OR = 3.14, p < 0.0001) and with self reported history of syphilis (OR = 1.88, p = 0.016), anogenital herpes (OR = 1.93, p = 0.017), gonorrhoea (OR = 2.43, p = 0.009) and hepatitis B (OR = 1.92, p = 0.010). In case control analysis, similar sexual behaviours (partner numbers and practices) were reported by HCV positive and HCV negative subjects except that HCV negative subjects more frequently reported engaging than HCV positive subject in unprotected receptive anal intercourse without ejaculation (OR = 0.61, p = 0.034), unprotected insertive (OR = 0.59, p = 0.039) and receptive (OR = 0.56, p = 0.016) oro-anal intercourse (rimming) and insertive fisting (OR = 0.48, p = 0.034). In multiple logistic regression analyses, only HIV-1 infection (OR = 3.18, p < 0.0001) and IDU in the previous six months (OR = 7.24, p < 0.0001) remained significantly associated with the presence of HCV antibody. \n CONCLUSIONS IDU was the major behavioural risk factor for HCV infection. If sexual or another from of transmission did occur, it may have been facilitated by concurrent HIV-1 infection.", "title": "Hepatitis C virus infection in a large cohort of homosexually active men: independent associations with HIV-1 infection and injecting drug use but not sexual behaviour." }, { "docid": "25014337", "text": "We previously identified a rare mutation in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT), I132M, which confers high-level resistance to the nonnucleoside RT inhibitors (NNRTIs) nevirapine and delavirdine. In this study, we have further characterized the role of this mutation in viral replication capacity and in resistance to other RT inhibitors. Surprisingly, our data show that I132M confers marked hypersusceptibility to the nucleoside analogs lamivudine (3TC) and tenofovir at both the virus and enzyme levels. Subunit-selective mutagenesis studies revealed that the mutation in the p51 subunit of RT was responsible for the increased sensitivity to the drugs, and transient kinetic analyses showed that this hypersusceptibility was due to I132M decreasing the enzyme's affinity for the natural dCTP substrate but increasing its affinity for 3TC-triphosphate. Furthermore, the replication capacity of HIV-1 containing I132M is severely impaired. This decrease in viral replication capacity could be partially or completely compensated for by the A62V or L214I mutation, respectively. Taken together, these results help to explain the infrequent selection of I132M in patients for whom NNRTI regimens are failing and furthermore demonstrate that a single mutation outside of the polymerase active site and inside of the p51 subunit of RT can significantly influence nucleotide selectivity.", "title": "The human immunodeficiency virus type 1 nonnucleoside reverse transcriptase inhibitor resistance mutation I132M confers hypersensitivity to nucleoside analogs." }, { "docid": "42708716", "text": "We report the cDNA cloning and characterization of a novel human inositol polyphosphate 5-phosphatase (5-phosphatase) that has substrate specificity unlike previously described members of this large gene family. All previously described members hydrolyze water soluble inositol phosphates. This enzyme hydrolyzes only lipid substrates, phosphatidylinositol 3,4,5-trisphosphate and phosphatidylinositol 4,5-bisphosphate. The cDNA isolated comprises 3110 base pairs and predicts a protein product of 644 amino acids and M(r) = 70,023. We designate this 5-phosphatase as type IV. It is a highly basic protein (pI = 8.8) and has the greatest affinity toward phosphatidylinositol 3,4,5-trisphosphate of known 5-phosphatases. The K(m) is 0.65 micrometer, 1/10 that of SHIP (5.95 micrometer), another 5-phosphatase that hydrolyzes phosphatidylinositol 3,4,5-trisphosphate. The activity of 5-phosphatase type IV is sensitive to the presence of detergents in the in vitro assay. Thus the enzyme hydrolyzes lipid substrates in the absence of detergents or in the presence of n-octyl beta-glucopyranoside or Triton X-100, but not in the presence of cetyltriethylammonium bromide, the detergent that has been used in other studies of the hydrolysis of phosphatidylinositol 4,5-bisphosphate. Remarkably SHIP, a 5-phosphatase previously characterized as hydrolyzing only substrates with d-3 phosphates, also readily hydrolyzed phosphatidylinositol 4,5-bisphosphate in the presence of n-octyl beta-glucopyranoside but not cetyltriethylammonium bromide. We used antibodies prepared against a peptide predicted by the cDNA to identify the 5-phosphatase type IV enzyme in human tissues and find that it is highly expressed in the brain as determined by Western blotting. We also performed Western blotting of mouse tissues and found high levels of expression in the brain, testes, and heart with lower levels of expression in other tissues. mRNA was detected in many tissues and cell lines as determined by Northern blotting.", "title": "The isolation and characterization of a cDNA encoding phospholipid-specific inositol polyphosphate 5-phosphatase." }, { "docid": "21274496", "text": "Simian immunodeficiency virus (SIV) naturally infects non-human primates in Africa. To date, 40 SIVs have been described both in natural hosts and in heterologous species. These viruses are highly diverse and the majority cluster in 6 relatively equidistant phylogenetic lineages. At least 8 SIVs are currently considered as recombinant viruses, based on different clustering patterns in different genomic regions. Only three types of genomes are known, based on the number of accessory genes: vpr-containing genomes, vpr-vpx containing genomes and vpr-vpu-containing genomes. vpx resulted by a duplication of the vpr gene following non-homologous recombination and is characteristic of SIVs infecting the Papionini tribe of monkeys and HIV-2 in humans. vpu is characteristic of SIVcpz and HIV-1 and may have originated from a recombination involving SIVs from cercopitecini monkeys. SIV seems to be non-pathogenic in the vast majority of natural hosts in spite of a high levels of viral replication. This is probably a consequence of virus-host adaptation, in which the incubation period of the disease generally exceeds the life span of the African primate host. SIVs also have a high propensity for cross-species transmission. In the new host, the outcome may vary from inapparent infection to highly pathogenic, the former being reported for African monkeys, whereas the latter being observed in macaques and humans. The high diversity of SIVs was generated by a high mutation rate due to a low fidelity of the reverse-transcriptase and active viral and host cell turnover, host-dependent evolution and recombination. Cross-species transmission is not rare, however preferential host switching may drive the majority of cross-species transmissions. Numerous SIVs tested so far are able to grow in vitro on human PBMC, therefore it has been postulated that SIV represents a threat for infection of humans in Central Africa and that AIDS is a zoonosis. However, although the simian origin of the two HIV types is broadly acknowledged, there are no data that AIDS is acquired like a zoonosis. SIV may undergo adaptation in the new human host in order to emerge in the general population. The study of SIV in their natural hosts should provide important clues to the real threat to human populations and also elucidate the mechanisms associated with a long-term persistent viral infection without clinical consequences for the host.", "title": "The history of SIVS and AIDS: epidemiology, phylogeny and biology of isolates from naturally SIV infected non-human primates (NHP) in Africa." }, { "docid": "1454773", "text": "The programmed death-1 (PD-1) receptor serves as an immunologic checkpoint, limiting bystander tissue damage and preventing the development of autoimmunity during inflammatory responses. PD-1 is expressed by activated T cells and downmodulates T-cell effector functions upon binding to its ligands, PD-L1 and PD-L2, on antigen-presenting cells. In patients with cancer, the expression of PD-1 on tumor-infiltrating lymphocytes and its interaction with the ligands on tumor and immune cells in the tumor microenvironment undermine antitumor immunity and support its rationale for PD-1 blockade in cancer immunotherapy. This report details the development and characterization of nivolumab, a fully human IgG4 (S228P) anti-PD-1 receptor-blocking monoclonal antibody. Nivolumab binds to PD-1 with high affinity and specificity, and effectively inhibits the interaction between PD-1 and its ligands. In vitro assays demonstrated the ability of nivolumab to potently enhance T-cell responses and cytokine production in the mixed lymphocyte reaction and superantigen or cytomegalovirus stimulation assays. No in vitro antibody-dependent cell-mediated or complement-dependent cytotoxicity was observed with the use of nivolumab and activated T cells as targets. Nivolumab treatment did not induce adverse immune-related events when given to cynomolgus macaques at high concentrations, independent of circulating anti-nivolumab antibodies where observed. These data provide a comprehensive preclinical characterization of nivolumab, for which antitumor activity and safety have been demonstrated in human clinical trials in various solid tumors.", "title": "In vitro characterization of the anti-PD-1 antibody nivolumab, BMS-936558, and in vivo toxicology in non-human primates." }, { "docid": "25842866", "text": "Most eukaryotic telomeres contain a repeating motif with stretches of guanine residues that form a 3'-terminal overhang extending beyond the telomeric duplex region. The telomeric repeat of hypotrichous ciliates, d(T(4)G(4)), forms a 16-nucleotide 3'-overhang. Such sequences can adopt parallel-stranded as well as antiparallel-stranded quadruplex conformations in vitro. Although it has been proposed that guanine-quadruplex conformations may have important cellular roles including telomere function, recombination, and transcription, evidence for the existence of this DNA structure in vivo has been elusive to date. We have generated high-affinity single-chain antibody fragment (scFv) probes for the guanine-quadruplex formed by the Stylonychia telomeric repeat, by ribosome display from the Human Combinatorial Antibody Library. Of the scFvs selected, one (Sty3) had an affinity of K(d) = 125 pM for the parallel-stranded guanine-quadruplex and could discriminate with at least 1,000-fold specificity between parallel or antiparallel quadruplex conformations formed by the same sequence motif. A second scFv (Sty49) bound both the parallel and antiparallel quadruplex with similar (K(d) = 3--5 nM) affinity. Indirect immunofluorescence studies show that Sty49 reacts specifically with the macronucleus but not the micronucleus of Stylonychia lemnae. The replication band, the region where replication and telomere elongation take place, was also not stained, suggesting that the guanine-quadruplex is resolved during replication. Our results provide experimental evidence that the telomeres of Stylonychia macronuclei adopt in vivo a guanine-quadruplex structure, indicating that this structure may have an important role for telomere functioning.", "title": "In vitro generated antibodies specific for telomeric guanine-quadruplex DNA react with Stylonychia lemnae macronuclei." }, { "docid": "22937651", "text": "Epstein-Barr virus (EBV) is associated with multiple sclerosis (MS), and antibodies to the EBV nuclear antigen-1 (EBNA-1) are consistently increased in MS patients. The hypothesis of this study is that anti-EBNA-1 antibodies cross-react with a self antigen in MS patients. We affinity purified anti-EBNA-1 antibodies from human plasma, used the anti-EBNA-1 to immunoprecipitate antigens from human brain, and identified bound antigens with mass spectrometry. Anti-EBNA-1 consistently bound heterogeneous nuclear ribonucleoprotein L (HNRNPL). We expressed both the long and short isoforms of this protein, and verified with Western blots and ELISA that the long isoform cross-reacts with EBNA-1. Immunohistochemistry demonstrated that anti-EBNA-1 bound to an antigen in the nucleus of cultured rat central nervous system cells. ELISA demonstrated the presence of antibodies to HNRNPL in the plasma of both healthy controls and MS patients, but anti-HNRNPL was not increased in MS patients. We conclude that HNRNPL is an autoantigen which cross-reacts with EBNA-1. The relevance of this autoantigen to MS and other autoimmune diseases remains to be investigated.", "title": "Antibodies specific for Epstein-Barr virus nuclear antigen-1 cross-react with human heterogeneous nuclear ribonucleoprotein L." }, { "docid": "9831859", "text": "Pancreatic stellate cells (PSC) produce the stromal reaction in pancreatic cancer, but their role in cancer progression is not fully elucidated. We examined the influence of PSCs on pancreatic cancer growth using (a) an orthotopic model of pancreatic cancer and (b) cultured human PSCs (hPSC) and human pancreatic cancer cell lines MiaPaCa-2 and Panc-1. Athymic mice received an intrapancreatic injection of saline, hPSCs, MiaPaCa-2 cells, or hPSCs + MiaPaCa-2. After 7 weeks, tumor size, metastases, and tumor histology were assessed. In vitro studies assessed the effect of cancer cell secretions on PSC migration and the effect of hPSC secretions on cancer cell proliferation, apoptosis, and migration. Possible mediators of the effects of hPSC secretions on cancer cell proliferation were examined using neutralizing antibodies. Compared with mice receiving MiaPaCa-2 cells alone, mice injected with hPSCs + MiaPaCa-2 exhibited (a) increased tumor size and regional and distant metastasis, (b) fibrotic bands (desmoplasia) containing activated PSCs within tumors, and (c) increased tumor cell numbers. In vitro studies showed that, in the presence of pancreatic cancer cells, PSC migration was significantly increased. Furthermore, hPSC secretions induced the proliferation and migration, but inhibited the apoptosis, of MiaPaCa-2 and Panc-1 cells. The proliferative effect of hPSC secretions on pancreatic cancer cells was inhibited in the presence of neutralizing antibody to platelet-derived growth factor. Our studies indicate a significant interaction between pancreatic cancer cells and stromal cells (PSCs) and imply that pancreatic cancer cells recruit stromal cells to establish an environment that promotes cancer progression.", "title": "Pancreatic stellate cells: partners in crime with pancreatic cancer cells." }, { "docid": "5548081", "text": "CONTEXT Some studies have inferred that an epidemic of Kaposi sarcoma-associated herpesvirus (KSHV) infection in homosexual men in the United States occurred concurrently with that of human immunodeficiency virus (HIV), but there have been no direct measurements of KSHV prevalence at the beginning of the HIV epidemic. \n OBJECTIVES To determine the prevalence of KSHV infection in homosexual men in San Francisco, Calif, at the beginning of the HIV epidemic in 1978 and 1979 and to examine changes in prevalence of KSHV at time points from 1978 through 1996 in light of changes in sexual behavior. \n DESIGN, SETTING, AND PARTICIPANTS Analysis of a clinic-based sample (n = 398) derived from the San Francisco City Clinic Cohort (ages 18-66 years) (n = 2666 for analyses herein) and from population-based samples from the San Francisco Men's Health Study (MHS) (ages 25-54 years) (n = 825 and 252) and the San Francisco Young Men's Health Study (YMHS) (ages 18-29 years) (n = 428-976, and 557); behavioral studies were longitudinal and KSHV prevalence studies were cross-sectional. \n MAIN OUTCOME MEASURES Antibodies against KSHV and HIV; sexual behaviors. \n RESULTS The prevalence of KSHV infection in 1978 and 1979 was 26.5% of 235 (a random sample) overall (weighted for HIV infection) vs 6.9% (128/1842) for HIV in the San Francisco City Clinic Cohort sample. The prevalence of KSHV infection remained essentially unchanged between an MHS sample of 252 in 1984 and 1985 (29.6%) and a YMHS sample of 557 in 1995 and 1996 (26.4%), while HIV prevalence dropped from 49.5% of 825 in 1984 and 1985 (MHS) to 17.6% of 428 in 1992 and 1993 (YMHS). The proportion of men practicing unprotected receptive anal intercourse with 1 or more partners declined from 54% to 11% during the 1984 through 1993 period (MHS) with similar though slightly higher values in the YMHS in 1992 and 1993; whereas for unprotected oral intercourse it ranged between 60% and 90% in the 1984 through 1996 period (MHS and YMHS). \n CONCLUSIONS Infection with KSHV was already highly prevalent in homosexual men when the HIV epidemic began in San Francisco, and its prevalence has been maintained at a nearly constant level. Any declines in the incidence of Kaposi sarcoma do not appear to be caused by a decline in KSHV transmission.", "title": "Prevalence of Kaposi sarcoma-associated herpesvirus infection in homosexual men at beginning of and during the HIV epidemic." } ]

[ { "docid": "19313533", "text": "The metabolic stress-sensing enzyme AMP-activated protein kinase (AMPK) is responsible for regulating metabolism in response to energy supply and demand. Drugs that activate AMPK may be useful in the treatment of metabolic diseases including type 2 diabetes. We have determined the crystal structure of AMPK in complex with its activator 5-(5-hydroxyl-isoxazol-3-yl)-furan-2-phosphonic acid (C2), revealing two C2-binding sites in the γ-subunit distinct from nucleotide sites. C2 acts synergistically with the drug A769662 to activate AMPK α1-containing complexes independent of upstream kinases. Our results show that dual drug therapies could be effective AMPK-targeting strategies to treat metabolic diseases.", "title": "Structural basis of allosteric and synergistic activation of AMPK by furan-2-phosphonic derivative C2 binding." } ]

[ { "docid": "24294572", "text": "The PI3K signaling pathway regulates cell growth and movement and is heavily mutated in cancer. Class I PI3Ks synthesize the lipid messenger PI(3,4,5)P3. PI(3,4,5)P3 can be dephosphorylated by 3- or 5-phosphatases, the latter producing PI(3,4)P2. The PTEN tumor suppressor is thought to function primarily as a PI(3,4,5)P3 3-phosphatase, limiting activation of this pathway. Here we show that PTEN also functions as a PI(3,4)P2 3-phosphatase, both in vitro and in vivo. PTEN is a major PI(3,4)P2 phosphatase in Mcf10a cytosol, and loss of PTEN and INPP4B, a known PI(3,4)P2 4-phosphatase, leads to synergistic accumulation of PI(3,4)P2, which correlated with increased invadopodia in epidermal growth factor (EGF)-stimulated cells. PTEN deletion increased PI(3,4)P2 levels in a mouse model of prostate cancer, and it inversely correlated with PI(3,4)P2 levels across several EGF-stimulated prostate and breast cancer lines. These results point to a role for PI(3,4)P2 in the phenotype caused by loss-of-function mutations or deletions in PTEN.", "title": "PTEN Regulates PI(3,4)P2 Signaling Downstream of Class I PI3K" }, { "docid": "26025820", "text": "The rat kidney ablation and infarction (A/I) model of subtotal or 5/6th nephrectomy is the most commonly studied model of nondiabetic chronic kidney disease (CKD). The A/I kidney at 1 wk exhibits reductions in kidney function, as determined by glomerular filtration rate, and diminished metabolic efficiency as determined by oxygen consumption per sodium transport (QO2/TNa). As renoprotective AMPK activity is affected by metabolic changes and cellular stress, we evaluated AMPK activity in this model system. We show that these early pathophysiological changes are accompanied by a paradoxical decrease in AMPK activity. Over time, these kidney parameters progressively worsen with extensive kidney structural, functional, metabolic, and fibrotic changes observed at 4 wk after A/I. We show that induction of AMPK activity with either metformin or 5-aminoimidazole-4-carboxamide ribonucleotide increases AMPK activity in this model and also corrects kidney metabolic inefficiency, improves kidney function, and ameliorates kidney fibrosis and structural alterations. We conclude that AMPK activity is reduced in the subtotal nephrectomy model of nondiabetic CKD, that altered regulation of AMPK is coincident with the progression of disease parameters, and that restoration of AMPK activity can suppress the progressive loss of function characteristic of this model. We propose that induction of AMPK activity may prove an effective therapeutic target for the treatment of nondiabetic CKD.", "title": "Induction of AMPK activity corrects early pathophysiological alterations in the subtotal nephrectomy model of chronic kidney disease." }, { "docid": "3973445", "text": "Adenosine 5′-monophosphate–activated protein kinase (AMPK) is a pivotal regulator of metabolism at cellular and organismal levels. AMPK also suppresses inflammation. We found that pharmacological activation of AMPK rapidly inhibited the Janus kinase (JAK)–signal transducer and activator of transcription (STAT) pathway in various cells. In vitro kinase assays revealed that AMPK directly phosphorylated two residues (Ser515 and Ser518) within the Src homology 2 domain of JAK1. Activation of AMPK enhanced the interaction between JAK1 and 14-3-3 proteins in cultured vascular endothelial cells and fibroblasts, an effect that required the presence of Ser515 and Ser518 and was abolished in cells lacking AMPK catalytic subunits. Mutation of Ser515 and Ser518 abolished AMPK-mediated inhibition of JAK-STAT signaling stimulated by either the sIL-6Rα/IL-6 complex or the expression of a constitutively active V658F-mutant JAK1 in human fibrosarcoma cells. Clinically used AMPK activators metformin and salicylate enhanced the inhibitory phosphorylation of endogenous JAK1 and inhibited STAT3 phosphorylation in primary vascular endothelial cells. Therefore, our findings reveal a mechanism by which JAK1 function and inflammatory signaling may be suppressed in response to metabolic stress and provide a mechanistic rationale for the investigation of AMPK activators in a range of diseases associated with enhanced activation of the JAK-STAT pathway.", "title": "Phosphorylation of Janus kinase 1 (JAK1) by AMP-activated protein kinase (AMPK) links energy sensing to anti-inflammatory signaling" }, { "docid": "9899292", "text": "Metformin is a widely used drug for treatment of type 2 diabetes with no defined cellular mechanism of action. Its glucose-lowering effect results from decreased hepatic glucose production and increased glucose utilization. Metformin's beneficial effects on circulating lipids have been linked to reduced fatty liver. AMP-activated protein kinase (AMPK) is a major cellular regulator of lipid and glucose metabolism. Here we report that metformin activates AMPK in hepatocytes; as a result, acetyl-CoA carboxylase (ACC) activity is reduced, fatty acid oxidation is induced, and expression of lipogenic enzymes is suppressed. Activation of AMPK by metformin or an adenosine analogue suppresses expression of SREBP-1, a key lipogenic transcription factor. In metformin-treated rats, hepatic expression of SREBP-1 (and other lipogenic) mRNAs and protein is reduced; activity of the AMPK target, ACC, is also reduced. Using a novel AMPK inhibitor, we find that AMPK activation is required for metformin's inhibitory effect on glucose production by hepatocytes. In isolated rat skeletal muscles, metformin stimulates glucose uptake coincident with AMPK activation. Activation of AMPK provides a unified explanation for the pleiotropic beneficial effects of this drug; these results also suggest that alternative means of modulating AMPK should be useful for the treatment of metabolic disorders.", "title": "Role of AMP-activated protein kinase in mechanism of metformin action." }, { "docid": "9752604", "text": "In light of the emerging interplay between redox and metabolic signaling pathways we investigated the potential cross talk between nuclear factor E2-related factor 2 (Nrf2) and AMP-activated kinase (AMPK), central regulators of the cellular redox and energy balance, respectively. Making use of xanthohumol (XN) as an activator of both the AMPK and the Nrf2 signaling pathway we show that AMPK exerts a positive influence on Nrf2/heme oxygenase (HO)-1 signaling in mouse embryonic fibroblasts. Genetic ablation and pharmacological inhibition of AMPK blunts Nrf2-dependent HO-1 expression by XN already at the mRNA level. XN leads to AMPK activation via interference with mitochondrial function and activation of liver kinase B1 as upstream AMPK kinase. The subsequent AMPK-mediated enhancement of the Nrf2/HO-1 response does not depend on inhibition of the mammalian target of rapamycin, inhibition of glycogen synthase kinase 3β, or altered abundance of Nrf2 (total and nuclear). However, reduced endoplasmic reticulum stress was identified and elaborated as a step in the AMPK-augmented Nrf2/HO-1 response. Overall, we shed more light on the hitherto incompletely understood cross talk between the LKB1/AMPK and the Nrf2/HO-1 axis revealing for the first time involvement of the unfolded protein response as an additional player and suggesting tight cooperation between signaling pathways controlling cellular redox, energy, or protein homeostasis.", "title": "Activated AMPK boosts the Nrf2/HO-1 signaling axis—A role for the unfolded protein response" }, { "docid": "3419709", "text": "Nonalcoholic fatty liver disease (NAFLD) is a growing worldwide epidemic and an important risk factor for the development of insulin resistance, type 2 diabetes, nonalcoholic steatohepatitis (NASH), and hepatic cellular carcinoma (HCC). Despite the prevalence of NAFLD, lifestyle interventions involving exercise and weight loss are the only accepted treatments for this disease. Over the last decade, numerous experimental compounds have been shown to improve NAFLD in preclinical animal models, and many of these therapeutics have been shown to increase the activity of the cellular energy sensor AMP-activated protein kinase (AMPK). Because AMPK activity is reduced by inflammation, obesity, and diabetes, increasing AMPK activity has been viewed as a viable therapeutic strategy to improve NAFLD. In this review, we propose three primary mechanisms by which AMPK activation may improve NAFLD. In addition, we examine the mechanisms by which AMPK is activated. Finally, we identify 27 studies that have used AMPK activators to reduce NAFLD. Future considerations for studies examining the relationship between AMPK and NAFLD are highlighted.", "title": "Treatment of nonalcoholic fatty liver disease: role of AMPK." }, { "docid": "49556906", "text": "Fibrosis is a pathological result of a dysfunctional repair response to tissue injury and occurs in a number of organs, including the lungs1. Cellular metabolism regulates tissue repair and remodelling responses to injury2-4. AMPK is a critical sensor of cellular bioenergetics and controls the switch from anabolic to catabolic metabolism5. However, the role of AMPK in fibrosis is not well understood. Here, we demonstrate that in humans with idiopathic pulmonary fibrosis (IPF) and in an experimental mouse model of lung fibrosis, AMPK activity is lower in fibrotic regions associated with metabolically active and apoptosis-resistant myofibroblasts. Pharmacological activation of AMPK in myofibroblasts from lungs of humans with IPF display lower fibrotic activity, along with enhanced mitochondrial biogenesis and normalization of sensitivity to apoptosis. In a bleomycin model of lung fibrosis in mice, metformin therapeutically accelerates the resolution of well-established fibrosis in an AMPK-dependent manner. These studies implicate deficient AMPK activation in non-resolving, pathologic fibrotic processes, and support a role for metformin (or other AMPK activators) to reverse established fibrosis by facilitating deactivation and apoptosis of myofibroblasts.", "title": "Metformin reverses established lung fibrosis in a bleomycin model" }, { "docid": "23974474", "text": "AMP-activated protein kinase (AMPK) is an energy-sensing enzyme whose activity is inhibited in settings of insulin resistance. Exposure to a high glucose concentration has recently been shown to increase phosphorylation of AMPK at Ser(485/491) of its α1/α2 subunit; however, the mechanism by which it does so is not known. Diacylglycerol (DAG), which is also increased in muscle exposed to high glucose, activates a number of signaling molecules including protein kinase (PK)C and PKD1. We sought to determine whether PKC or PKD1 is involved in inhibition of AMPK by causing Ser(485/491) phosphorylation in skeletal muscle cells. C2C12 myotubes were treated with the PKC/D1 activator phorbol 12-myristate 13-acetate (PMA), which acts as a DAG mimetic. This caused dose- and time-dependent increases in AMPK Ser(485/491) phosphorylation, which was associated with a ∼60% decrease in AMPKα2 activity. Expression of a phosphodefective AMPKα2 mutant (S491A) prevented the PMA-induced reduction in AMPK activity. Serine phosphorylation and inhibition of AMPK activity were partially prevented by the broad PKC inhibitor Gö6983 and fully prevented by the specific PKD1 inhibitor CRT0066101. Genetic knockdown of PKD1 also prevented Ser(485/491) phosphorylation of AMPK. Inhibition of previously identified kinases that phosphorylate AMPK at this site (Akt, S6K, and ERK) did not prevent these events. PMA treatment also caused impairments in insulin-signaling through Akt, which were prevented by PKD1 inhibition. Finally, recombinant PKD1 phosphorylated AMPKα2 at Ser(491) in cell-free conditions. These results identify PKD1 as a novel upstream kinase of AMPKα2 Ser(491) that plays a negative role in insulin signaling in muscle cells.", "title": "PKD1 Inhibits AMPKα2 through Phosphorylation of Serine 491 and Impairs Insulin Signaling in Skeletal Muscle Cells." }, { "docid": "24721866", "text": "Macrophage-derived foam cells play important roles in the progression of atherosclerosis. We reported previously that ERK1/2-dependent granulocyte/macrophage colony-stimulating factor (GM-CSF) expression, leading to p38 MAPK/ Akt signaling, is important for oxidized low density lipoprotein (Ox-LDL)-induced macrophage proliferation. Here, we investigated whether activation of AMP-activated protein kinase (AMPK) could suppress macrophage proliferation. Ox-LDL-induced proliferation of mouse peritoneal macrophages was assessed by [(3)H]thymidine incorporation and cell counting assays. The proliferation was significantly inhibited by the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) and restored by dominant-negative AMPKalpha1, suggesting that AMPK activation suppressed macrophage proliferation. AICAR partially suppressed Ox-LDL-induced ERK1/2 phosphorylation and GM-CSF expression, suggesting that another mechanism is also involved in the AICAR-mediated suppression of macrophage proliferation. AICAR suppressed GM-CSF-induced macrophage proliferation without suppressing p38 MAPK/Akt signaling. GM-CSF suppressed p53 phosphorylation and expression and induced Rb phosphorylation. Overexpression of p53 or p27(kip) suppressed GM-CSF-induced macrophage proliferation. AICAR induced cell cycle arrest, increased p53 phosphorylation and expression, and suppressed GM-CSF-induced Rb phosphorylation via AMPK activation. Moreover, AICAR induced p21(cip) and p27(kip) expression via AMPK activation, and small interfering RNA (siRNA) of p21(cip) and p27(kip) restored AICAR-mediated suppression of macrophage proliferation. In conclusion, AMPK activation suppressed Ox-LDL-induced macrophage proliferation by suppressing GM-CSF expression and inducing cell cycle arrest. These effects of AMPK activation may represent therapeutic targets for atherosclerosis.", "title": "Activation of AMP-activated protein kinase suppresses oxidized low-density lipoprotein-induced macrophage proliferation." }, { "docid": "1590744", "text": "The AMP-activated protein kinase (AMPK) is a key regulator of cellular and whole-body energy homeostasis, which acts to restore energy homoeostasis whenever cellular energy charge is depleted. Over the last 2 decades, it has become apparent that AMPK regulates several other cellular functions and has specific roles in cardiovascular tissues, acting to regulate cardiac metabolism and contractile function, as well as promoting anticontractile, anti-inflammatory, and antiatherogenic actions in blood vessels. In this review, we discuss the role of AMPK in the cardiovascular system, including the molecular basis of mutations in AMPK that alter cardiac physiology and the proposed mechanisms by which AMPK regulates vascular function under physiological and pathophysiological conditions.", "title": "AMP-Activated Protein Kinase: An Ubiquitous Signaling Pathway With Key Roles in the Cardiovascular System" }, { "docid": "3504761", "text": "The MAP kinase kinase kinase TGFβ-activated kinase 1 (TAK1) is activated by TLRs, IL-1, TNF, and TGFβ and in turn activates IKK-NF-κB and JNK, which regulate cell survival, growth, tumorigenesis, and metabolism. TAK1 signaling also upregulates AMPK activity and autophagy. Here, we investigated TAK1-dependent regulation of autophagy, lipid metabolism, and tumorigenesis in the liver. Fasted mice with hepatocyte-specific deletion of Tak1 exhibited severe hepatosteatosis with increased mTORC1 activity and suppression of autophagy compared with their WT counterparts. TAK1-deficient hepatocytes exhibited suppressed AMPK activity and autophagy in response to starvation or metformin treatment; however, ectopic activation of AMPK restored autophagy in these cells. Peroxisome proliferator-activated receptor α (PPARα) target genes and β-oxidation, which regulate hepatic lipid degradation, were also suppressed in hepatocytes lacking TAK1. Due to suppression of autophagy and β-oxidation, a high-fat diet challenge aggravated steatohepatitis in mice with hepatocyte-specific deletion of Tak1. Notably, inhibition of mTORC1 restored autophagy and PPARα target gene expression in TAK1-deficient livers, indicating that TAK1 acts upstream of mTORC1. mTORC1 inhibition also suppressed spontaneous liver fibrosis and hepatocarcinogenesis in animals with hepatocyte-specific deletion of Tak1. These data indicate that TAK1 regulates hepatic lipid metabolism and tumorigenesis via the AMPK/mTORC1 axis, affecting both autophagy and PPARα activity.", "title": "TAK1-mediated autophagy and fatty acid oxidation prevent hepatosteatosis and tumorigenesis." }, { "docid": "3761017", "text": "BACKGROUND Metformin, a widely used hypoglycemic drug, reduces stroke incidence and alleviates chronic inflammation in clinical trials. However, the effect of metformin in ischemic stroke is unclear. Here, we investigated the effect of metformin on ischemic stroke in mice and further explored the possible underlying mechanisms. \n METHODS Ninety-eight adult male CD-1 mice underwent 90-minute transient middle cerebral artery occlusion (tMCAO). Metformin (200 mg/kg) was administrated for up to 14 days. Neurobehavioral outcomes, brain infarct volume, inflammatory factors, blood-brain barrier (BBB) permeability and AMPK signaling pathways were evaluated following tMCAO. Oxygen glucose deprivation was performed on bEND.3 cells to explore the mechanisms of metformin in inhibiting inflammatory signaling pathways. \n RESULTS Infarct volume was reduced in metformin-treated mice compared to the control group following tMCAO (P < 0.05). Neurobehavioral outcomes were greatly improved in metformin-treated mice (P < 0.05). MPO+ cells, Gr1+ cells, MPO activity and BBB permeability were decreased after metformin administration (P < 0.05). In addition, metformin activated AMPK phosphorylation, inhibited NF-κB activation, down-regulated cytokine (IL-1β, IL-6, TNF-α) and ICAM-1 expression following tMCAO (P < 0.05). Furthermore, metformin activated AMPK signaling pathway and alleviated oxygen-glucose deprivation-induced ICAM-1 expression in bEND.3 cells (P < 0.05). Compound C, a selective AMPK inhibitor, eliminated this promotional effect. \n CONCLUSIONS Metformin down-regulated ICAM-1 in an AMPK-dependent manner, which could effectively prevent ischemia-induced brain injury by alleviating neutrophil infiltration, suggesting that metformin is a promising therapeutic agent in stroke therapy.", "title": "Metformin attenuates blood-brain barrier disruption in mice following middle cerebral artery occlusion" }, { "docid": "22036571", "text": "The AMP-activated protein kinase (AMPK) is a ubiquitous mammalian protein kinase important in the adaptation of cells to metabolic stress. The enzyme is a heterotrimer, consisting of a catalytic alpha subunit and regulatory beta and gamma subunits, each of which is a member of a larger isoform family. The enzyme is allosterically regulated by AMP and by phosphorylation of the alpha subunit. The beta subunit is post-translationally modified by myristoylation and multi-site phosphorylation. In the present study, we have examined the impact of post-translational modification of the beta-1 subunit on enzyme activity, heterotrimer assembly and subcellular localization, using site-directed mutagenesis and expression of subunits in mammalian cells. Removal of the myristoylation site (G2A mutant) results in a 4-fold activation of the enzyme and relocalization of the beta subunit from a particulate extranuclear distribution to a more homogenous cell distribution. Mutation of the serine-108 phosphorylation site to alanine is associated with enzyme inhibition, but no change in cell localization. In contrast, the phosphorylation site mutations, SS24, 25AA and S182A, while having no effects on enzyme activity, are associated with nuclear redistribution of the subunit. Taken together, these results indicate that both myristoylation and phosphorylation of the beta subunit of AMPK modulate enzyme activity and subunit cellular localization, increasing the complexity of AMPK regulation.", "title": "Post-translational modifications of the beta-1 subunit of AMP-activated protein kinase affect enzyme activity and cellular localization." }, { "docid": "1686997", "text": "The oxidative pentose phosphate pathway (PPP) contributes to tumour growth, but the precise contribution of 6-phosphogluconate dehydrogenase (6PGD), the third enzyme in this pathway, to tumorigenesis remains unclear. We found that suppression of 6PGD decreased lipogenesis and RNA biosynthesis and elevated ROS levels in cancer cells, attenuating cell proliferation and tumour growth. 6PGD-mediated production of ribulose-5-phosphate (Ru-5-P) inhibits AMPK activation by disrupting the active LKB1 complex, thereby activating acetyl-CoA carboxylase 1 and lipogenesis. Ru-5-P and NADPH are thought to be precursors in RNA biosynthesis and lipogenesis, respectively; thus, our findings provide an additional link between the oxidative PPP and lipogenesis through Ru-5-P-dependent inhibition of LKB1-AMPK signalling. Moreover, we identified and developed 6PGD inhibitors, physcion and its derivative S3, that effectively inhibited 6PGD, cancer cell proliferation and tumour growth in nude mice xenografts without obvious toxicity, suggesting that 6PGD could be an anticancer target.", "title": "6-phosphogluconate dehydrogenase links oxidative PPP, lipogenesis and tumor growth by inhibiting LKB1-AMPK signaling" }, { "docid": "14541844", "text": "Highly conserved among eukaryotic cells, the AMP-activated kinase (AMPK) is a central regulator of carbon metabolism. To map the complete network of interactions around AMPK in yeast (Snf1) and to evaluate the role of its regulatory subunit Snf4, we measured global mRNA, protein and metabolite levels in wild type, Deltasnf1, Deltasnf4, and Deltasnf1Deltasnf4 knockout strains. Using four newly developed computational tools, including novel DOGMA sub-network analysis, we showed the benefits of three-level ome-data integration to uncover the global Snf1 kinase role in yeast. We for the first time identified Snf1's global regulation on gene and protein expression levels, and showed that yeast Snf1 has a far more extensive function in controlling energy metabolism than reported earlier. Additionally, we identified complementary roles of Snf1 and Snf4. Similar to the function of AMPK in humans, our findings showed that Snf1 is a low-energy checkpoint and that yeast can be used more extensively as a model system for studying the molecular mechanisms underlying the global regulation of AMPK in mammals, failure of which leads to metabolic diseases.", "title": "Reconstruction of the yeast Snf1 kinase regulatory network reveals its role as a global energy regulator" }, { "docid": "1605196", "text": "Successful generation of induced pluripotent stem cells entails a major metabolic switch from mitochondrial oxidative phosphorylation to glycolysis during the reprogramming process. The mechanism of this metabolic reprogramming, however, remains elusive. Here, our results suggest that an Atg5-independent autophagic process mediates mitochondrial clearance, a characteristic event involved in the metabolic switch. We found that blocking such autophagy, but not canonical autophagy, inhibits mitochondrial clearance, in turn, preventing iPSC induction. Furthermore, AMPK seems to be upstream of this autophagic pathway and can be targeted by small molecules to modulate mitochondrial clearance during metabolic reprogramming. Our work not only reveals that the Atg5-independent autophagy is crucial for establishing pluripotency, but it also suggests that iPSC generation and tumorigenesis share a similar metabolic switch.", "title": "Atg5-independent autophagy regulates mitochondrial clearance and is essential for iPSC reprogramming" }, { "docid": "4695107", "text": "The problem of antibiotic resistance, which has limited the use of cheap and old antibiotics, has necessitated the need for a continued search for new antimicrobial compounds. Understanding the mechanisms of resistance is important in the development of strategies to solving the problem. Active efflux of drugs, alteration of target sites and enzymatic degradations are the strategies by which pathogenic bacteria acquire or develop intrinsic resistance to antibiotics. Multi-drug resistance (MDR) pumps, capable of recognizing and expelling a variety of structurally unrelated compounds from the bacterial cell and conferring resistance to a wide range of antibiotics have since been characterized in many gram positive and gram negative pathogens like Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and, more recently, in mycobacteria. The ability of some chemical compounds (called MDR inhibitors or resistance modifying agents) to modify the resistance phenotype in bacteria by working synergistically with antibiotics in vitro has since been observed. The search for such compounds which can be combined with antibiotics in the treatment of drug resistant infections may be an alternative to overcoming the problem of resistance in bacteria. Crude extracts of medicinal plants stand out as veritable sources of potential resistance modifying agents and the African biosphere promises to be a potential source of such compounds owing to its rich plant species diversity.", "title": "The challenges of overcoming antibiotic resistance: Plant extracts as potential sources of antimicrobial and resistance modifying agents" }, { "docid": "38533515", "text": "The SNF1/AMP-activated protein kinase (AMPK) family maintains the balance between ATP production and consumption in all eukaryotic cells. The kinases are heterotrimers that comprise a catalytic subunit and regulatory subunits that sense cellular energy levels. When energy status is compromised, the system activates catabolic pathways and switches off protein, carbohydrate and lipid biosynthesis, as well as cell growth and proliferation. Surprisingly, recent results indicate that the AMPK system is also important in functions that go beyond the regulation of energy homeostasis, such as the maintenance of cell polarity in epithelial cells.", "title": "AMP-activated/SNF1 protein kinases: conserved guardians of cellular energy" }, { "docid": "9021186", "text": "The persistence of transcriptionally silent but replication-competent HIV-1 reservoirs in Highly Active Anti-Retroviral Therapy (HAART)-treated infected individuals, represents a major hurdle to virus eradication. Activation of HIV-1 gene expression in these cells together with an efficient HAART has been proposed as an adjuvant therapy aimed at decreasing the pool of latent viral reservoirs. Using the latently-infected U1 monocytic cell line and latently-infected J-Lat T-cell clones, we here demonstrated a strong synergistic activation of HIV-1 production by clinically used histone deacetylase inhibitors (HDACIs) combined with prostratin, a non-tumor-promoting nuclear factor (NF)- kappaB inducer. In J-Lat cells, we showed that this synergism was due, at least partially, to the synergistic recruitment of unresponsive cells into the expressing cell population. A combination of prostratin+HDACI synergistically activated the 5' Long Terminal Repeat (5'LTR) from HIV-1 Major group subtypes representing the most prevalent viral genetic forms, as shown by transient transfection reporter assays. Mechanistically, HDACIs increased prostratin-induced DNA-binding activity of nuclear NF-kappaB and degradation of cytoplasmic NF-kappaB inhibitor, IkappaBalpha . Moreover, the combined treatment prostratin+HDACI caused a more pronounced nucleosomal remodeling in the U1 viral promoter region than the treatments with the compounds alone. This more pronounced remodeling correlated with a synergistic reactivation of HIV-1 transcription following the combined treatment prostratin+HDACI, as demonstrated by measuring recruitment of RNA polymerase II to the 5'LTR and both initiated and elongated transcripts. The physiological relevance of the prostratin+HDACI synergism was shown in CD8(+)-depleted peripheral blood mononuclear cells from HAART-treated patients with undetectable viral load. Moreover, this combined treatment reactivated viral replication in resting CD4(+) T cells isolated from similar patients. Our results suggest that combinations of different kinds of proviral activators may have important implications for reducing the size of latent HIV-1 reservoirs in HAART-treated patients.", "title": "Synergistic Activation of HIV-1 Expression by Deacetylase Inhibitors and Prostratin: Implications for Treatment of Latent Infection" } ]

[ { "docid": "2177022", "text": "Chemokines orchestrate immune cell trafficking by eliciting either directed or random migration and by activating integrins in order to induce cell adhesion. Analyzing dendritic cell (DC) migration, we showed that these distinct cellular responses depended on the mode of chemokine presentation within tissues. The surface-immobilized form of the chemokine CCL21, the heparan sulfate-anchoring ligand of the CC-chemokine receptor 7 (CCR7), caused random movement of DCs that was confined to the chemokine-presenting surface because it triggered integrin-mediated adhesion. Upon direct contact with CCL21, DCs truncated the anchoring residues of CCL21, thereby releasing it from the solid phase. Soluble CCL21 functionally resembles the second CCR7 ligand, CCL19, which lacks anchoring residues and forms soluble gradients. Both soluble CCR7 ligands triggered chemotactic movement, but not surface adhesion. Adhesive random migration and directional steering cooperate to produce dynamic but spatially restricted locomotion patterns closely resembling the cellular dynamics observed in secondary lymphoid organs.", "title": "Immobilized chemokine fields and soluble chemokine gradients cooperatively shape migration patterns of dendritic cells." } ]

[ { "docid": "40590358", "text": "The pro-drug FTY720 is undergoing phase III clinical trials for prevention of allograft rejection. After phosphorylation, FTY720 targets the G protein-coupled-sphingosine-1-phosphate receptor 1 (S1PR1) on lymphocytes, thereby inhibiting their egress from lymphoid organs and their recirculation to inflammatory sites. Potential effects on dendritic cell (DC) trafficking have not been evaluated. Here, we demonstrate the expression of all five S1PR subtypes (S1PR1-5) by murine DCs. Administration of FTY720 to C57BL/10 mice markedly reduced circulating T and B lymphocytes within 24 h, but not blood-borne DCs, which were enhanced significantly for up to 96 h, while DCs in lymph nodes and spleen were reduced. Numbers of adoptively transferred, fluorochrome-labeled syngeneic or allogeneic DCs in blood were increased significantly in FTY720-treated animals, while donor-derived DCs and allostimulatory activity for host naïve T cells within the spleen were reduced. Administration of the selective S1PR1 agonist SEW2871 significantly enhanced circulating DC numbers. Flow analysis revealed that CD11b, CD31/PECAM-1, CD54/ICAM-1 and CCR7 expression on blood-borne DCs was downregulated following FTY720 administration. Transendothelial migration of FTY720-P-treated immature DCs to the CCR7 ligand CCL19 was reduced. These novel data suggest that modulation of DC trafficking by FTY720 may contribute to its immunosuppressive effects.", "title": "The sphingosine-1-phosphate receptor agonist FTY720 modulates dendritic cell trafficking in vivo." }, { "docid": "13778710", "text": "Chemokine-like receptor 1 (CMKLR1), also known as ChemR23, and chemokine (C-C motif) receptor-like 2 (CCRL2) are 7-transmembrane receptors that were cloned in the late 1990s based on their homology to known G-protein-coupled receptors. They were previously orphan receptors without any known biological roles; however, recent studies identified ligands for these receptors and their functions have begun to be unveiled. The plasma protein-derived chemoattractant chemerin is a ligand for CMKLR1 and activation of CMKLR1 with chemerin induces the migration of macrophages and dendritic cells (DCs) in vitro, suggesting a proinflammatory role. However, in vivo studies using CMKLR-deficient mice suggest an anti-inflammatory role for this receptor, possibly due to the recruitment of tolerogenic plasmacytoid DCs. Chemerin/CMKLR1 interaction also promotes adipogenesis and angiogenesis. The anti-inflammatory lipid mediator, resolving E1, is another CMKLR1 ligand and it inhibits leukocyte infiltration and proinflammatory gene expression. These divergent results suggest that CMKLR1 is a multifunctional receptor. The chemokine CCL5 and CCL19 are reported to bind to CCRL2. Like Duffy antigen for chemokine receptor (DARC), D6 and CCX-CKR, CCRL2 does not signal, but it constitutively recycles, potentially reducing local concentration of CCL5 and CCL19 and subsequent immune responses. Surprisingly, chemerin, a ligand for CMKLR1, is a ligand for CCRL2. CCRL2 binds chemerin and increases local chemerin concentration to efficiently present it to CMKLR1 on nearby cells, providing a link between CCRL2 and CMKLR1. Although these findings suggest an anti-inflammatory role, a recent study using CCRL2-deficient mice indicates a proinflammatory role; thus, CCRL2 may also be multifunctional. Further studies using CMKLR1- or CCRL2-deficient mice are needed to further define the role of these receptors in immune responses and other cellular processes.", "title": "Chemokine-like receptor 1 (CMKLR1) and chemokine (C-C motif) receptor-like 2 (CCRL2); two multifunctional receptors with unusual properties." }, { "docid": "25942757", "text": "The substantial importance of P-selectin glycoprotein ligand 1 (PSGL-1) in leukocyte trafficking has continued to emerge beyond its initial identification as a selectin ligand. PSGL-1 seemed to be a relatively simple molecule with an extracellular mucin domain extended as a flexible rod, teleologically consistent with its primary role in tethering leukocytes to endothelial selectins. The rolling interaction between leukocyte and endothelium mediated by this selectin-PSGL-1 interaction requires branched O-glycan extensions on specific PSGL-1 amino acid residues. In some cells, such as neutrophils, the glycosyltransferases involved in formation of the O-glycans are constitutively expressed, while in other cells, such as T cells, they are expressed only after appropriate activation. Thus, PSGL-1 supports leukocyte recruitment in both innate and adaptive arms of the immune response. A complex array of amino acids within the selectins engage multiple sugar residues of the branched O-glycans on PSGL-1 and provide the molecular interactions responsible for the velcro-like catch bonds that support leukocyte rolling. Such binding of PSGL-1 can also induce signaling events that influence cell phenotype and function. Scrutiny of PSGL-1 has revealed a better understanding of how it performs as a selectin ligand and yielded unexpected insights that extend its scope from supporting leukocyte rolling in inflammatory settings to homeostasis including stem cell homing to the thymus and mature T-cell homing to secondary lymphoid organs. PSGL-1 has been found to bind homeostatic chemokines CCL19 and CCL21 and to support the chemotactic response to these chemokines. Surprisingly, the O-glycan modifications of PSGL-1 that support rolling mediated by selectins in inflammatory conditions interfere with PSGL-1 binding to homeostatic chemokines and thereby limit responsiveness to the chemotactic cues used in steady state T-cell traffic. The multi-level influence of PSGL-1 on cell traffic in both inflammatory and steady state settings is therefore substantially determined by the orchestrated addition of O-glycans. However, central as specific O-glycosylation is to PSGL-1 function, in vivo regulation of PSGL-1 glycosylation in T cells remains poorly understood. It is our purpose herein to review what is known, and not known, of PSGL-1 glycosylation and to update understanding of PSGL-1 functional scope.", "title": "PSGL-1 function in immunity and steady state homeostasis." }, { "docid": "6123924", "text": "Immune tolerance and activation depend on precise control over the number and function of immunosuppressive Foxp3(+) regulatory T (T reg) cells, and the importance of IL-2 in maintaining tolerance and preventing autoimmunity is clear. However, the homeostatic requirement for IL-2 among specific populations of peripheral T reg cells remains poorly understood. We show that IL-2 selectively maintains a population of quiescent CD44(lo)CD62L(hi) T reg cells that gain access to paracrine IL-2 produced in the T cell zones of secondary lymphoid tissues due to their expression of the chemokine receptor CCR7. In contrast, CD44(hi)CD62L(lo)CCR7(lo) T reg cells that populate nonlymphoid tissues do not access IL-2-prevalent regions in vivo and are insensitive to IL-2 blockade; instead, their maintenance depends on continued signaling through the co-stimulatory receptor ICOS (inducible co-stimulator). Thus, we define a fundamental homeostatic subdivision in T reg cell populations based on their localization and provide an integrated framework for understanding how T reg cell abundance and function are controlled by unique signals in different tissue environments.", "title": "CCR7 provides localized access to IL-2 and defines homeostatically distinct regulatory T cell subsets" }, { "docid": "12100963", "text": "Memory/effector T cells efficiently migrate into extralymphoid tissues and sites of infection, providing immunosurveillance and a first line of defense against invading pathogens. Even though it is a potential means to regulate the size, quality, and duration of a tissue infiltrate, T cell egress from infected tissues is poorly understood. Using a mouse model of influenza A virus infection, we found that CD8 effector T cells egressed from the infected lung in a CCR7-dependent manner. In contrast, following antigen recognition, effector CD8 T cell egress decreased and CCR7 function was reduced in vivo and in vitro, indicating that the exit of CD8 T cells from infected tissues is tightly regulated. Our data suggest that the regulation of T cell egress is a mechanism to retain antigen-specific effectors at the site of infection to promote viral clearance, while decreasing the numbers of bystander T cells and preventing overt inflammation.", "title": "Tissue exit: a novel control point in the accumulation of antigen-specific CD8 T cells in the influenza a virus-infected lung." }, { "docid": "20148808", "text": "The mammalian gastrointestinal tract harbors a microbial community with metabolic activity critical for host health, including metabolites that can modulate effector functions of immune cells. Mice treated with vancomycin have an altered microbiome and metabolite profile, exhibit exacerbated T helper type 2 cell (Th2) responses, and are more susceptible to allergic lung inflammation. Here we show that dietary supplementation with short-chain fatty acids (SCFAs) ameliorates this enhanced asthma susceptibility by modulating the activity of T cells and dendritic cells (DCs). Dysbiotic mice treated with SCFAs have fewer interleukin-4 (IL4)-producing CD4+ T cells and decreased levels of circulating immunoglobulin E (IgE). In addition, DCs exposed to SCFAs activate T cells less robustly, are less motile in response to CCL19 in vitro, and exhibit a dampened ability to transport inhaled allergens to lung draining nodes. Our data thus demonstrate that gut dysbiosis can exacerbate allergic lung inflammation through both T cell- and DC-dependent mechanisms that are inhibited by SCFAs.", "title": "Microbiome-driven allergic lung inflammation is ameliorated by short-chain fatty acids" }, { "docid": "28644298", "text": "Epstein-Barr virus (EBV) latency III infection converts B lymphocytes into lymphoblastoid cell lines (LCLs) by expressing EBV nuclear and membrane proteins, EBNAs, and latent membrane proteins (LMPs), which regulate transcription through Notch and tumor necrosis factor receptor pathways. The role of NF-kappa B in LMP1 and overall EBV latency III transcriptional effects was investigated by treating LCLs with BAY11-7082 (BAY11). BAY11 rapidly and irreversibly inhibited NF-kappa B, decreased mitochondrial membrane potential, induced apoptosis, and altered LCL gene expression. BAY11 effects were similar to those of an NF-kappa B inhibitor, Delta N-I kappa B alpha, in effecting decreased JNK1 expression and in microarray analyses. More than 80% of array elements that decreased with Delta N-I kappa B alpha expression decreased with BAY11 treatment. Newly identified NF-kappa B-induced, LMP1-induced, and EBV-induced genes included pleckstrin, Jun-B, c-FLIP, CIP4, and I kappa B epsilon. Of 776 significantly changed array elements, 134 were fourfold upregulated in EBV latency III, and 74 were fourfold upregulated with LMP1 expression alone, whereas only 28 were more than fourfold downregulated by EBV latency III. EBV latency III-regulated gene products mediate cell migration (EBI2, CCR7, RGS1, RANTES, MIP1 alpha, MIP1 beta, CXCR5, and RGS13), antigen presentation (major histocompatibility complex proteins and JAW1), mitogen-activated protein kinase pathway (DUSP5 and p62Dok), and interferon (IFN) signaling (IFN-gamma R alpha, IRF-4, and STAT1). Comparison of EBV latency III LCL gene expression to immunoglobulin M (IgM)-stimulated B cells, germinal-center B cells, and germinal-center-derived lymphomas clustered LCLs with IgM-stimulated B cells separately from germinal-center cells or germinal-center lymphoma cells. Expression of IRF-2, AIM1, ASK1, SNF2L2, and components of IFN signaling pathways further distinguished EBV latency III-infected B cells from IgM-stimulated or germinal-center B cells.", "title": "Role of NF-kappa B in cell survival and transcription of latent membrane protein 1-expressing or Epstein-Barr virus latency III-infected cells." }, { "docid": "20690388", "text": "Natural killer (NK) cell activation is strictly regulated to ensure that healthy cells are preserved, but tumour-transformed or virus-infected cells are recognized and eliminated. To carry out this selective killing, NK cells have an ample repertoire of receptors on their surface. Signalling by inhibitory and activating receptors by interaction with their ligands will determine whether the NK cell becomes activated and kills the target cell. Here, we show reduced expression of NKp46, NKp30, DNAM-1, CD244 and CD94/NKG2C activating receptors on NK cells from acute myeloid leukaemia patients. This reduction may be induced by chronic exposure to their ligands on leukaemic blasts. The analysis of ligands for NK cell-activating receptors showed that leukaemic blasts from the majority of patients express ligands for NK cell-activating receptors. DNAM-1 ligands are frequently expressed on blasts, whereas the expression of the NKG2D ligand MICA/B is found in half of the patients and CD48, a ligand for CD244, in only one-fourth of the patients. The decreased expression of NK cell-activating receptors and/or the heterogeneous expression of ligands for major receptors on leukaemic blasts can lead to an inadequate tumour immunosurveillance by NK cells. A better knowledge of the activating receptor repertoire on NK cells and their putative ligands on blasts together with the possibility to modulate their expression will open new possibilities for the use of NK cells in immunotherapy against leukaemia.", "title": "Human NK cells in acute myeloid leukaemia patients: analysis of NK cell-activating receptors and their ligands" }, { "docid": "23938319", "text": "Retinoid receptors (RARs and RXRs) are ligand-activated transcription factors that regulate the transcription of target genes by recruiting coregulator complexes at cognate promoters. To understand the effects of heterodimerization and ligand binding on coactivator recruitment, we solved the crystal structure of the complex between the RARbeta/RXRalpha ligand-binding domain heterodimer, its 9-cis retinoic acid ligand, and an LXXLL-containing peptide (termed NR box 2) derived from the nuclear receptor interaction domain (NID) of the TRAP220 coactivator. In parallel, we measured the binding affinities of the isolated NR box 2 peptide or the full-length NID of the coactivator SRC-1 for retinoid receptors in the presence of various types of ligands. Our correlative analysis of three-dimensional structures and fluorescence data reveals that heterodimerization does not significantly alter the structure of individual subunits or their intrinsic capacity to interact with NR box 2. Similarly, we show that the ability of a protomer to recruit NR box 2 does not vary as a function of the ligand binding status of the partner receptor. In contrast, the strength of the overall association between the heterodimer and the full-length SRC-1 NID is dictated by the combinatorial action of RAR and RXR ligands, the simultaneous presence of the two receptor agonists being required for highest binding affinity. We identified an LXXLL peptide-driven mechanism by which the concerted reorientation of three phenylalanine side chains generates an \"aromatic clamp\" that locks the RXR activation helix H12 in the transcriptionally active conformation. Finally, we show how variations of helix H11-ligand interactions can alter the communication pathway linking helices H11, H12, and the connecting loop L11-12 to the coactivator-binding site. Together, our results reveal molecular and structural features that impact on the ligand-dependent interaction of the RAR/RXR heterodimer with nuclear receptor coactivators.", "title": "Characterization of the interaction between retinoic acid receptor/retinoid X receptor (RAR/RXR) heterodimers and transcriptional coactivators through structural and fluorescence anisotropy studies." }, { "docid": "12265561", "text": "The conformation of the ligand in complex with a macromolecular target can be studied by nuclear magnetic resonance (NMR) in solution for both tightly and weakly forming complexes. In the weak binding regime (k(off) > 10(4) Hz), the structure of the bound ligand is accessible also for very large complexes (>100 kDa), which are not amenable to NMR studies in the tight binding regime. Here I review the state-of-the-art NMR methodology used for screening ligands and for the structural investigation of bound ligand conformations, in both tight and weak binding regimes. The advantages and disadvantages of each approach are critically described. The NMR methodology used to investigate transiently forming complexes has expanded considerably in the past few years, opening new possibilities for a detailed description of ligand-target interactions. Novel methods for the determination of the bound ligand conformation, in particular transferred cross-correlated relaxation, are thoroughly reviewed, and their advantages with respect to established methodology are discussed, using the epothilone-tubulin complex as a primary example.", "title": "Ligand-target interactions: what can we learn from NMR?" }, { "docid": "10607877", "text": "Cell surface receptors have been extensively studied because they initiate and regulate signal transduction cascades leading to a variety of functional cellular outcomes. An important class of immune receptors (e.g., T-cell antigen receptors) whose ligands are anchored to the surfaces of other cells remain poorly understood. The mechanism by which ligand binding initiates receptor phosphorylation, a process termed \"receptor triggering\", remains controversial. Recently, direct measurements of the (two-dimensional) receptor-ligand complex lifetimes at cell-cell interface were found to be smaller than (three-dimensional) lifetimes in solution but the underlying mechanism is unknown. At the cell-cell interface, the receptor-ligand complex spans a short intermembrane distance (15 nm) compared to long surface molecules (LSMs) whose ectodomains span >40 nm and these LSMs include phosphatases (e.g., CD45) that dephosphorylate the receptor. It has been proposed that size-based segregation of LSMs from a receptor-ligand complex is a mechanism of receptor triggering but it is unclear whether the mechanochemistry supports such small-scale segregation. Here we present a nanometer-scale mathematical model that couples membrane elasticity with the compressional stiffness and lateral mobility of LSMs. We find robust supradiffusive segregation of LSMs from a single receptor-ligand complex. The model predicts that LSM redistribution will result in a time-dependent tension on the complex leading to a decreased two-dimensional lifetime. Interestingly, the model predicts a nonlinear relationship between the three- and two-dimensional lifetimes, which can enhance the ability of receptors to discriminate between similar ligands.", "title": "Mechanical modulation of receptor-ligand interactions at cell-cell interfaces." }, { "docid": "40383969", "text": "TGF-beta ligands stimulate diverse cellular differentiation and growth responses by signaling through type I and II receptors. Ligand antagonists, such as follistatin, block signaling and are essential regulators of physiological responses. Here we report the structure of activin A, a TGF-beta ligand, bound to the high-affinity antagonist follistatin. Two follistatin molecules encircle activin, neutralizing the ligand by burying one-third of its residues and its receptor binding sites. Previous studies have suggested that type I receptor binding would not be blocked by follistatin, but the crystal structure reveals that the follistatin N-terminal domain has an unexpected fold that mimics a universal type I receptor motif and occupies this receptor binding site. The formation of follistatin:BMP:type I receptor complexes can be explained by the stoichiometric and geometric arrangement of the activin:follistatin complex. The mode of ligand binding by follistatin has important implications for its ability to neutralize homo- and heterodimeric ligands of this growth factor family.", "title": "The structure of the follistatin:activin complex reveals antagonism of both type I and type II receptor binding." }, { "docid": "40963697", "text": "The family of tumor necrosis factor receptors (TNFRs) and their ligands form a regulatory signaling network that controls immune responses. Various members of this receptor family respond differently to the soluble and membrane-bound forms of their respective ligands. However, the determining factors and underlying molecular mechanisms of this diversity are not yet understood. Using an established system of chimeric TNFRs and novel ligand variants mimicking the bioactivity of membrane-bound TNF (mTNF), we demonstrate that the membrane-proximal extracellular stalk regions of TNFR1 and TNFR2 are crucial in controlling responsiveness to soluble TNF (sTNF). We show that the stalk region of TNFR2, in contrast to the corresponding part of TNFR1, efficiently inhibits both the receptor's enrichment/clustering in particular cell membrane regions and ligand-independent homotypic receptor preassembly, thereby preventing sTNF-induced, but not mTNF-induced, signaling. Thus, the stalk regions of the two TNFRs not only have implications for additional TNFR family members, but also provide potential targets for therapeutic intervention.", "title": "The tumor necrosis factor receptor stalk regions define responsiveness to soluble versus membrane-bound ligand." }, { "docid": "994800", "text": "T cell receptor (TCR) ligation is required for the extrathymic differentiation of forkhead box p3(+) (Foxp3(+)) regulatory T cells. Several lines of evidence indicate that weak TCR stimulation favors induction of Foxp3 in the periphery; however, it remains to be determined how TCR ligand potency influences this process. We characterized the density and affinity of TCR ligand favorable for Foxp3 induction and found that a low dose of a strong agonist resulted in maximal induction of Foxp3 in vivo. Initial Foxp3 induction by weak agonist peptide could be enhanced by disruption of TCR-peptide major histocompatibility complex (pMHC) interactions or alteration of peptide dose. However, time course experiments revealed that Foxp3-positive cells induced by weak agonist stimulation are deleted, along with their Foxp3-negative counterparts, whereas Foxp3-positive cells induced by low doses of the strong agonist persist. Our results suggest that, together, pMHC ligand potency, density, and duration of TCR interactions define a cumulative quantity of TCR stimulation that determines initial peripheral Foxp3 induction. However, in the persistence of induced Foxp3(+) T cells, TCR ligand potency and density are noninterchangeable factors that influence the route to peripheral tolerance.", "title": "TCR ligand density and affinity determine peripheral induction of Foxp3 in vivo" }, { "docid": "13868795", "text": "Ligation of the CD28 receptor on T cells provides a critical second signal alongside T cell receptor (TCR) ligation for naive T cell activation. Here, we discuss the expression, structure, and biochemistry of CD28 and its ligands. CD28 signals play a key role in many T cell processes, including cytoskeletal remodeling, production of cytokines, survival, and differentiation. CD28 ligation leads to unique epigenetic, transcriptional, and post-translational changes in T cells that cannot be recapitulated by TCR ligation alone. We discuss the function of CD28 and its ligands in both effector and regulatory T cells. CD28 is critical for regulatory T cell survival and the maintenance of immune homeostasis. We outline the roles that CD28 and its family members play in human disease and we review the clinical efficacy of drugs that block CD28 ligands. Despite the centrality of CD28 and its family members and ligands to immune function, many aspects of CD28 biology remain unclear. Translation of a basic understanding of CD28 function into immunomodulatory therapeutics has been uneven, with both successes and failures. Such real-world results might stem from multiple factors, including complex receptor-ligand interactions among CD28 family members, differences between the mouse and human CD28 families, and cell-type specific roles of CD28 family members.", "title": "CD28 Costimulation: From Mechanism to Therapy." }, { "docid": "2714623", "text": "How membrane receptors initiate signal transduction upon ligand binding is a matter of intense scrutiny. The T cell receptor complex (TCR-CD3) is composed of TCR alpha/beta ligand binding subunits bound to the CD3 subunits responsible for signal transduction. Although it has long been speculated that TCR-CD3 may undergo a conformational change, confirmation is still lacking. We present strong evidence that ligand engagement of TCR-CD3 induces a conformational change that exposes a proline-rich sequence in CD3 epsilon and results in recruitment of the adaptor protein Nck. This occurs earlier than and independently of tyrosine kinase activation. Finally, by interfering with Nck-CD3 epsilon association in vivo, we demonstrate that TCR-CD3 recruitment of Nck is critical for maturation of the immune synapse and for T cell activation.", "title": "Recruitment of Nck by CD3ϵ Reveals a Ligand-Induced Conformational Change Essential for T Cell Receptor Signaling and Synapse Formation" }, { "docid": "33499189", "text": "T cell receptor (TCR-CD3) triggering involves both receptor clustering and conformational changes at the cytoplasmic tails of the CD3 subunits. The mechanism by which TCRalphabeta ligand binding confers conformational changes to CD3 is unknown. By using well-defined ligands, we showed that induction of the conformational change requires both multivalent engagement and the mobility restriction of the TCR-CD3 imposed by the plasma membrane. The conformational change is elicited by cooperative rearrangements of two TCR-CD3 complexes and does not require accompanying changes in the structure of the TCRalphabeta ectodomains. This conformational change at CD3 reverts upon ligand dissociation and is required for T cell activation. Thus, our permissive geometry model provides a molecular mechanism that rationalizes how the information of ligand binding to TCRalphabeta is transmitted to the CD3 subunits and to the intracellular signaling machinery.", "title": "Full activation of the T cell receptor requires both clustering and conformational changes at CD3." }, { "docid": "7621534", "text": "Although chemokines are well established to function in immunity and endothelial cell activation and proliferation, a rapidly growing literature suggests that CXC Chemokine receptors CXCR3, CXCR4 and CXCR7 are critical in the development and progression of solid tumors. The effect of these chemokine receptors in tumorigenesis is mediated via interactions with shared ligands I-TAC (CXCL11) and SDF-1 (CXCL12). Over the last decade, CXCR4 has been extensively reported to be overexpressed in most human solid tumors and has earned considerable attention toward elucidating its role in cancer metastasis. To enrich the existing armamentarium of anti-cancerous agents, many inhibitors of CXCL12-CXCR4 axis have emerged as additional or alternative agents for neo-adjuvant treatments and even many of them are in preclinical and clinical stages of their development. However, the discovery of CXCR7 as another receptor for CXCL12 with rather high binding affinity and recent reports about its involvement in cancer progression, has questioned the potential of \"selective blockade\" of CXCR4 as cancer chemotherapeutics. Interestingly, CXCR7 can also bind another chemokine CXCL11, which is an established ligand for CXCR3. Recent reports have documented that CXCR3 and their ligands are overexpressed in different solid tumors and regulate tumor growth and metastasis. Therefore, it is important to consider the interactions and crosstalk between these three chemokine receptors and their ligand mediated signaling cascades for the development of effective anti-cancer therapies. Emerging evidence also indicates that these receptors are differentially expressed in tumor endothelial cells as well as in cancer stem cells, suggesting their direct role in regulating tumor angiogenesis and metastasis. In this review, we will focus on the signals mediated by this receptor trio via their shared ligands and their role in tumor growth and progression.", "title": "Chemokine receptor trio: CXCR3, CXCR4 and CXCR7 crosstalk via CXCL11 and CXCL12." }, { "docid": "13639330", "text": "Nuclear receptors undergo ligand-dependent conformational changes that are required for corepressor-coactivator exchange, but whether there is an actual requirement for specific epigenetic landmarks to impose ligand dependency for gene activation remains unknown. Here we report an unexpected and general strategy that is based on the requirement for specific cohorts of inhibitory histone methyltransferases (HMTs) to impose gene-specific gatekeeper functions that prevent unliganded nuclear receptors and other classes of regulated transcription factors from binding to their target gene promoters and causing constitutive gene activation in the absence of stimulating signals. This strategy, based at least in part on an HMT-dependent inhibitory histone code, imposes a requirement for specific histone demethylases, including LSD1, to permit ligand- and signal-dependent activation of regulated gene expression. These events link an inhibitory methylation component of the histone code to a broadly used strategy that circumvents pathological constitutive gene induction by physiologically regulated transcription factors.", "title": "Histone Methylation-Dependent Mechanisms Impose Ligand Dependency for Gene Activation by Nuclear Receptors" } ]

[ { "docid": "2177022", "text": "Chemokines orchestrate immune cell trafficking by eliciting either directed or random migration and by activating integrins in order to induce cell adhesion. Analyzing dendritic cell (DC) migration, we showed that these distinct cellular responses depended on the mode of chemokine presentation within tissues. The surface-immobilized form of the chemokine CCL21, the heparan sulfate-anchoring ligand of the CC-chemokine receptor 7 (CCR7), caused random movement of DCs that was confined to the chemokine-presenting surface because it triggered integrin-mediated adhesion. Upon direct contact with CCL21, DCs truncated the anchoring residues of CCL21, thereby releasing it from the solid phase. Soluble CCL21 functionally resembles the second CCR7 ligand, CCL19, which lacks anchoring residues and forms soluble gradients. Both soluble CCR7 ligands triggered chemotactic movement, but not surface adhesion. Adhesive random migration and directional steering cooperate to produce dynamic but spatially restricted locomotion patterns closely resembling the cellular dynamics observed in secondary lymphoid organs.", "title": "Immobilized chemokine fields and soluble chemokine gradients cooperatively shape migration patterns of dendritic cells." } ]

[ { "docid": "13778710", "text": "Chemokine-like receptor 1 (CMKLR1), also known as ChemR23, and chemokine (C-C motif) receptor-like 2 (CCRL2) are 7-transmembrane receptors that were cloned in the late 1990s based on their homology to known G-protein-coupled receptors. They were previously orphan receptors without any known biological roles; however, recent studies identified ligands for these receptors and their functions have begun to be unveiled. The plasma protein-derived chemoattractant chemerin is a ligand for CMKLR1 and activation of CMKLR1 with chemerin induces the migration of macrophages and dendritic cells (DCs) in vitro, suggesting a proinflammatory role. However, in vivo studies using CMKLR-deficient mice suggest an anti-inflammatory role for this receptor, possibly due to the recruitment of tolerogenic plasmacytoid DCs. Chemerin/CMKLR1 interaction also promotes adipogenesis and angiogenesis. The anti-inflammatory lipid mediator, resolving E1, is another CMKLR1 ligand and it inhibits leukocyte infiltration and proinflammatory gene expression. These divergent results suggest that CMKLR1 is a multifunctional receptor. The chemokine CCL5 and CCL19 are reported to bind to CCRL2. Like Duffy antigen for chemokine receptor (DARC), D6 and CCX-CKR, CCRL2 does not signal, but it constitutively recycles, potentially reducing local concentration of CCL5 and CCL19 and subsequent immune responses. Surprisingly, chemerin, a ligand for CMKLR1, is a ligand for CCRL2. CCRL2 binds chemerin and increases local chemerin concentration to efficiently present it to CMKLR1 on nearby cells, providing a link between CCRL2 and CMKLR1. Although these findings suggest an anti-inflammatory role, a recent study using CCRL2-deficient mice indicates a proinflammatory role; thus, CCRL2 may also be multifunctional. Further studies using CMKLR1- or CCRL2-deficient mice are needed to further define the role of these receptors in immune responses and other cellular processes.", "title": "Chemokine-like receptor 1 (CMKLR1) and chemokine (C-C motif) receptor-like 2 (CCRL2); two multifunctional receptors with unusual properties." }, { "docid": "40590358", "text": "The pro-drug FTY720 is undergoing phase III clinical trials for prevention of allograft rejection. After phosphorylation, FTY720 targets the G protein-coupled-sphingosine-1-phosphate receptor 1 (S1PR1) on lymphocytes, thereby inhibiting their egress from lymphoid organs and their recirculation to inflammatory sites. Potential effects on dendritic cell (DC) trafficking have not been evaluated. Here, we demonstrate the expression of all five S1PR subtypes (S1PR1-5) by murine DCs. Administration of FTY720 to C57BL/10 mice markedly reduced circulating T and B lymphocytes within 24 h, but not blood-borne DCs, which were enhanced significantly for up to 96 h, while DCs in lymph nodes and spleen were reduced. Numbers of adoptively transferred, fluorochrome-labeled syngeneic or allogeneic DCs in blood were increased significantly in FTY720-treated animals, while donor-derived DCs and allostimulatory activity for host naïve T cells within the spleen were reduced. Administration of the selective S1PR1 agonist SEW2871 significantly enhanced circulating DC numbers. Flow analysis revealed that CD11b, CD31/PECAM-1, CD54/ICAM-1 and CCR7 expression on blood-borne DCs was downregulated following FTY720 administration. Transendothelial migration of FTY720-P-treated immature DCs to the CCR7 ligand CCL19 was reduced. These novel data suggest that modulation of DC trafficking by FTY720 may contribute to its immunosuppressive effects.", "title": "The sphingosine-1-phosphate receptor agonist FTY720 modulates dendritic cell trafficking in vivo." }, { "docid": "25937484", "text": "The lower respiratory tract of cigarette smokers contains an increased amount of iron that is predominantly sequestered within alveolar macrophages (AM), but is also present in alveolar epithelial fluid. Extracellular ferritin-bound iron could potentially be released by reductants present in cigarette smoke and catalyze generation of highly reactive hydroxyl radicals capable of causing oxidant injury. To determine whether AM are a source of alveolar extracellular ferritin and iron, we assessed in vitro release of iron, ferritin, and transferrin by AM recovered by bronchoalveolar lavage (BAL) of 27 healthy subjects including nine nonsmokers (NS), nine light smokers (LS), and nine heavy smokers (HS). Release of iron in vitro over 20 h was increased in AM recovered from LS (2.24 +/- 0.21 nmol/10(6) AM/20 h, p < 0.001) and HS (3.11 +/- 0.32 nmol/10(6) AM, p < 0.001) compared with NS (1.28 +/- 0.08 nmol/10(6) AM). Release of ferritin in vitro over 20 h was also increased in AM recovered from LS (71 +/- 24 ng/10(6) AM, p < 0.05) and HS (176 +/- 35 ng/10(6), p < 0.001) compared with NS (18 +/- 3 ng/10(6) AM). AM recovered from 12 smokers (8 HS, 4 LS) contained greater than 10 nmol of iron per 10(6) cells. These iron-loaded AM released a greater percentage of cell ferritin stores in vitro over 4 h (8.4% +/- 1.1, p < 0.01) than did AM from NS (3.2% +/- 0.6). Release of lactate dehydrogenase (LDH) over 4 h was substantially less (2.9% +/- 0.3, p < 0.001) than ferritin release.(ABSTRACT TRUNCATED AT 250 WORDS)", "title": "Increased release of ferritin and iron by iron-loaded alveolar macrophages in cigarette smokers." }, { "docid": "8494570", "text": "BACKGROUND Recent studies suggested that human/mammalian genomes are divided into large, discrete domains that are units of chromosome organization. CTCF, a CCCTC binding factor, has a diverse role in genome regulation including transcriptional regulation, chromosome-boundary insulation, DNA replication, and chromatin packaging. It remains unclear whether a subset of CTCF binding sites plays a functional role in establishing/maintaining chromatin topological domains. \n RESULTS We systematically analysed the genomic, transcriptomic and epigenetic profiles of the CTCF binding sites in 56 human cell lines from ENCODE. We identified ~24,000 CTCF sites (referred to as constitutive sites) that were bound in more than 90% of the cell lines. Our analysis revealed: 1) constitutive CTCF loci were located in constitutive open chromatin and often co-localized with constitutive cohesin loci; 2) most constitutive CTCF loci were distant from transcription start sites and lacked CpG islands but were enriched with the full-spectrum CTCF motifs: a recently reported 33/34-mer and two other potentially novel (22/26-mer); 3) more importantly, most constitutive CTCF loci were present in CTCF-mediated chromatin interactions detected by ChIA-PET and these pair-wise interactions occurred predominantly within, but not between, topological domains identified by Hi-C. CONCLUSIONS Our results suggest that the constitutive CTCF sites may play a role in organizing/maintaining the recently identified topological domains that are common across most human cells.", "title": "Characterization of constitutive CTCF/cohesin loci: a possible role in establishing topological domains in mammalian genomes" }, { "docid": "25942757", "text": "The substantial importance of P-selectin glycoprotein ligand 1 (PSGL-1) in leukocyte trafficking has continued to emerge beyond its initial identification as a selectin ligand. PSGL-1 seemed to be a relatively simple molecule with an extracellular mucin domain extended as a flexible rod, teleologically consistent with its primary role in tethering leukocytes to endothelial selectins. The rolling interaction between leukocyte and endothelium mediated by this selectin-PSGL-1 interaction requires branched O-glycan extensions on specific PSGL-1 amino acid residues. In some cells, such as neutrophils, the glycosyltransferases involved in formation of the O-glycans are constitutively expressed, while in other cells, such as T cells, they are expressed only after appropriate activation. Thus, PSGL-1 supports leukocyte recruitment in both innate and adaptive arms of the immune response. A complex array of amino acids within the selectins engage multiple sugar residues of the branched O-glycans on PSGL-1 and provide the molecular interactions responsible for the velcro-like catch bonds that support leukocyte rolling. Such binding of PSGL-1 can also induce signaling events that influence cell phenotype and function. Scrutiny of PSGL-1 has revealed a better understanding of how it performs as a selectin ligand and yielded unexpected insights that extend its scope from supporting leukocyte rolling in inflammatory settings to homeostasis including stem cell homing to the thymus and mature T-cell homing to secondary lymphoid organs. PSGL-1 has been found to bind homeostatic chemokines CCL19 and CCL21 and to support the chemotactic response to these chemokines. Surprisingly, the O-glycan modifications of PSGL-1 that support rolling mediated by selectins in inflammatory conditions interfere with PSGL-1 binding to homeostatic chemokines and thereby limit responsiveness to the chemotactic cues used in steady state T-cell traffic. The multi-level influence of PSGL-1 on cell traffic in both inflammatory and steady state settings is therefore substantially determined by the orchestrated addition of O-glycans. However, central as specific O-glycosylation is to PSGL-1 function, in vivo regulation of PSGL-1 glycosylation in T cells remains poorly understood. It is our purpose herein to review what is known, and not known, of PSGL-1 glycosylation and to update understanding of PSGL-1 functional scope.", "title": "PSGL-1 function in immunity and steady state homeostasis." }, { "docid": "23634484", "text": "A predominantly nuclear RNA-binding protein, HuR translocates to the cytoplasm in response to stress and proliferative signals, where it stabilizes or modulates the translation of target mRNAs. Here, we present evidence that HuR phosphorylation at S202 by the G2-phase kinase Cdk1 influences its subcellular distribution. HuR was specifically phosphorylated in synchronous G2-phase cultures; its cytoplasmic levels increased by Cdk1-inhibitory interventions and declined in response to Cdk1-activating interventions. In keeping with the prominently cytoplasmic location of the nonphosphorylatable point mutant HuR(S202A), phospho-HuR(S202) was shown to be predominantly nuclear using a novel anti-phospho-HuR(S202) antibody. The enhanced cytoplasmic presence of unphosphorylated HuR was linked to its decreased association with 14-3-3 and to its heightened binding to target mRNAs. Our findings suggest that Cdk1 phosphorylates HuR during G2, thereby helping to retain it in the nucleus in association with 14-3-3 and hindering its post-transcriptional function and anti-apoptotic influence.", "title": "Nuclear HuR accumulation through phosphorylation by Cdk1." }, { "docid": "14333540", "text": "Neural crest (NC) cells arise in the dorsal neural tube (NT) and migrate into the embryo to develop into many different cell types. A major unresolved question is when and how the fate of NC cells is decided. There is widespread evidence for multipotential NC cells, whose fates are decided during or after migration. There is also some evidence that the NC is already divided into subpopulations of discrete precursors within the NT. We have investigated this question in the mouse embryo. We find that a subpopulation of cells on the most dorsomedial aspect of the NT express the receptor tyrosine kinase Kit (previously known as c-kit), emigrate exclusively into the developing dermis, and then express definitive markers of the melanocyte lineage. These are thus melanocyte progenitor cells. They are generated predominantly at the midbrain-hindbrain junction and cervical trunk, with significant numbers also in lower trunk. Other cells within the dorsal NT are Kit-, migrate ventrally, and, from embryonic day 9.5, express the neurotrophin receptor p75. These cells most likely only give rise to ventral NC derivatives such as neurons and glia. The p75+ cells are located ventrolateral to the Kit+ cells in areas of the NT where these two cell types are found. These data provide direct in vivo evidence for NC lineage segregation within the mouse neural tube.", "title": "Neural crest cell lineage segregation in the mouse neural tube." }, { "docid": "2832403", "text": "BACKGROUND Recent studies suggest that betaKlotho (KLB) and endocrine FGF19 and FGF21 redirect FGFR signaling to regulation of metabolic homeostasis and suppression of obesity and diabetes. However, the identity of the predominant metabolic tissue in which a major FGFR-KLB resides that critically mediates the differential actions and metabolism effects of FGF19 and FGF21 remain unclear. \n METHODOLOGY/PRINCIPAL FINDINGS We determined the receptor and tissue specificity of FGF21 in comparison to FGF19 by using direct, sensitive and quantitative binding kinetics, and downstream signal transduction and expression of early response gene upon administration of FGF19 and FGF21 in mice. We found that FGF21 binds FGFR1 with much higher affinity than FGFR4 in presence of KLB; while FGF19 binds both FGFR1 and FGFR4 in presence of KLB with comparable affinity. The interaction of FGF21 with FGFR4-KLB is very weak even at high concentration and could be negligible at physiological concentration. Both FGF19 and FGF21 but not FGF1 exhibit binding affinity to KLB. The binding of FGF1 is dependent on where FGFRs are present. Both FGF19 and FGF21 are unable to displace the FGF1 binding, and conversely FGF1 cannot displace FGF19 and FGF21 binding. These results indicate that KLB is an indispensable mediator for the binding of FGF19 and FGF21 to FGFRs that is not required for FGF1. Although FGF19 can predominantly activate the responses of the liver and to a less extent the adipose tissue, FGF21 can do so significantly only in the adipose tissue and adipocytes. Among several metabolic and endocrine tissues, the response of adipose tissue to FGF21 is predominant, and can be blunted by the ablation of KLB or FGFR1. \n CONCLUSIONS Our results indicate that unlike FGF19, FGF21 is unable to bind FGFR4-KLB complex with affinity comparable to FGFR1-KLB, and therefore, at physiological concentration less likely to directly and significantly target the liver where FGFR4-KLB predominantly resides. However, both FGF21 and FGF19 have the potential to activate responses of primarily the adipose tissue where FGFR1-KLB resides.", "title": "Differential Specificity of Endocrine FGF19 and FGF21 to FGFR1 and FGFR4 in Complex with KLB" }, { "docid": "15778034", "text": "H2A.Z is an evolutionary conserved histone variant involved in transcriptional regulation, antisilencing, silencing, and genome stability. The mechanism(s) by which H2A.Z regulates these various biological functions remains poorly defined, in part due to the lack of knowledge regarding its physical location along chromosomes and the bearing it has in regulating chromatin structure. Here we mapped H2A.Z across the yeast genome at an approximately 300-bp resolution, using chromatin immunoprecipitation combined with tiling microarrays. We have identified 4,862 small regions—typically one or two nucleosomes wide—decorated with H2A.Z. Those “Z loci” are predominantly found within specific nucleosomes in the promoter of inactive genes all across the genome. Furthermore, we have shown that H2A.Z can regulate nucleosome positioning at the GAL1 promoter. Within HZAD domains, the regions where H2A.Z shows an antisilencing function, H2A.Z is localized in a wider pattern, suggesting that the variant histone regulates a silencing and transcriptional activation via different mechanisms. Our data suggest that the incorporation of H2A.Z into specific promoter-bound nucleosomes configures chromatin structure to poise genes for transcriptional activation. The relevance of these findings to higher eukaryotes is discussed.", "title": "Variant Histone H2A.Z Is Globally Localized to the Promoters of Inactive Yeast Genes and Regulates Nucleosome Positioning" }, { "docid": "18938992", "text": "Virally infected cells degrade intracellular viral proteins proteolytically and present the resulting peptides in association with major histocompatibility complex (MHC) class I molecules to CD8+ cytotoxic T lymphocytes (CTLs). These cells are normally prone to CTL-mediated elimination. However, several viruses have evolved strategies to avoid detection by the immune system that interfere with the pathway of antigen presentation. Epstein-Barr virus (EBV) expresses a predominantly late protein, the BCRF1 gene product vIL-10, that is similar in sequence to the human interleukin-10 (hIL-10). We show here that vIL-10 affects the expression of one of the two transporter proteins (TAPs) associated with antigen presentation. Similarly, hIL-10 showed the same activity. Expression of the LMP2 and TAP1 genes but not expression of TAP2 or LMP7 is efficiently downregulated, indicating a specific IL-10 effect on the two divergently transcribed TAP1 and LMP2 genes. Downregulation of TAP1 by IL-10 hampers the transport of peptide antigens into the endoplasmatic reticulum, as shown in the TAP-specific peptide transporter assay, their loading onto empty MHC I molecules, and the subsequent translocation to the cell surface. As a consequence, IL-10 causes a general reduction of surface MHC I molecules on B lymphocytes that might also affect the recognition of EBV-infected cells by cytotoxic T cells.", "title": "Downregulation of TAP1 in B lymphocytes by cellular and Epstein-Barr virus-encoded interleukin-10." }, { "docid": "20148808", "text": "The mammalian gastrointestinal tract harbors a microbial community with metabolic activity critical for host health, including metabolites that can modulate effector functions of immune cells. Mice treated with vancomycin have an altered microbiome and metabolite profile, exhibit exacerbated T helper type 2 cell (Th2) responses, and are more susceptible to allergic lung inflammation. Here we show that dietary supplementation with short-chain fatty acids (SCFAs) ameliorates this enhanced asthma susceptibility by modulating the activity of T cells and dendritic cells (DCs). Dysbiotic mice treated with SCFAs have fewer interleukin-4 (IL4)-producing CD4+ T cells and decreased levels of circulating immunoglobulin E (IgE). In addition, DCs exposed to SCFAs activate T cells less robustly, are less motile in response to CCL19 in vitro, and exhibit a dampened ability to transport inhaled allergens to lung draining nodes. Our data thus demonstrate that gut dysbiosis can exacerbate allergic lung inflammation through both T cell- and DC-dependent mechanisms that are inhibited by SCFAs.", "title": "Microbiome-driven allergic lung inflammation is ameliorated by short-chain fatty acids" }, { "docid": "36606083", "text": "Many fundamental aspects of DNA replication, such as the exact locations where DNA synthesis is initiated and terminated, how frequently origins are used, and how fork progression is influenced by transcription, are poorly understood. Via the deep sequencing of Okazaki fragments, we comprehensively document replication fork directionality throughout the S. cerevisiae genome, which permits the systematic analysis of initiation, origin efficiency, fork progression, and termination. We show that leading-strand initiation preferentially occurs within a nucleosome-free region at replication origins. Using a strain in which late origins can be induced to fire early, we show that replication termination is a largely passive phenomenon that does not rely on cis-acting sequences or replication fork pausing. The replication profile is predominantly determined by the kinetics of origin firing, allowing us to reconstruct chromosome-wide timing profiles from an asynchronous culture.", "title": "Quantitative, genome-wide analysis of eukaryotic replication initiation and termination." }, { "docid": "13116880", "text": "The mammalian blood system, containing more than 10 distinct mature cell types, stands on one specific cell type, hematopoietic stem cell (HSC). Within the system, only HSCs possess the ability of both multipotency and self-renewal. Multipotency is the ability to differentiate into all functional blood cells. Self-renewal is the ability to give rise to HSC itself without differentiation. Since mature blood cells (MBCs) are predominantly short-lived, HSCs continuously provide more differentiated progenitors while properly maintaining the HSC pool size throughout life by precisely balancing self-renewal and differentiation. Thus, understanding the mechanisms of self-renewal and differentiation of HSC has been a central issue. In this review, we focus on the hierarchical structure of the hematopoietic system, the current understanding of microenvironment and molecular cues regulating self-renewal and differentiation of adult HSCs, and the currently emerging systems approaches to understand HSC biology.", "title": "Hematopoietic stem cell: self-renewal versus differentiation." }, { "docid": "10074251", "text": "Protoplasmic astrocytes are increasingly thought to interact extensively with neuronal elements in the brain and to influence their activity. Recent reports have also begun to suggest that physiologically, and perhaps functionally, diverse forms of these cells may be present in the CNS. Our current understanding of astrocyte form and distribution is based predominantly on studies that used the astrocytic marker glial fibrillary acidic protein (GFAP) and on studies using metal-impregnation techniques. The prevalent opinion, based on studies using these methods, is that astrocytic processes overlap extensively and primarily share the underlying neuropil. However, both of these techniques have serious shortcomings for visualizing the interactions among these structurally complex cells. In the present study, intracellular injection combined with immunohistochemistry for GFAP show that GFAP delineates only approximately 15% of the total volume of the astrocyte. As a result, GFAP-based images have led to incorrect conclusions regarding the interaction of processes of neighboring astrocytes. To investigate these interactions in detail, groups of adjacent protoplasmic astrocytes in the CA1 stratum radiatum were injected with fluorescent intracellular tracers of distinctive emissive wavelengths and analyzed using three-dimensional (3D) confocal analysis and electron microscopy. Our findings show that protoplasmic astrocytes establish primarily exclusive territories. The knowledge of how the complex morphology of protoplasmic astrocytes affects their 3D relationships with other astrocytes, oligodendroglia, neurons, and vasculature of the brain should have important implications for our understanding of nervous system function.", "title": "Protoplasmic astrocytes in CA1 stratum radiatum occupy separate anatomical domains." }, { "docid": "43385013", "text": "It has been proposed that epithelial-mesenchymal transition (EMT) in mammary epithelial cells and breast cancer cells generates stem cell features, and that the presence of EMT characteristics in claudin-low breast tumors reveals their origin in basal stem cells. It remains to be determined, however, whether EMT is an inherent property of normal basal stem cells, and if the presence of a mesenchymal-like phenotype is required for the maintenance of all their stem cell properties. We used nontumorigenic basal cell lines as models of normal stem cells/progenitors and demonstrate that these cell lines contain an epithelial subpopulation (\"EpCAM+,\" epithelial cell adhesion molecule positive [EpCAM(pos)]/CD49f(high)) that spontaneously generates mesenchymal-like cells (\"Fibros,\" EpCAM(neg)/CD49f(med/low)) through EMT. Importantly, stem cell/progenitor properties such as regenerative potential, high aldehyde dehydrogenase 1 activity, and formation of three-dimensional acini-like structures predominantly reside within EpCAM+ cells, while Fibros exhibit invasive behavior and mammosphere-forming ability. A gene expression profiling meta-analysis established that EpCAM+ cells show a luminal progenitor-like expression pattern, while Fibros most closely resemble stromal fibroblasts but not stem cells. Moreover, Fibros exhibit partial myoepithelial traits and strong similarities with claudin-low breast cancer cells. Finally, we demonstrate that Slug and Zeb1 EMT-inducers control the progenitor and mesenchymal-like phenotype in EpCAM+ cells and Fibros, respectively, by inhibiting luminal differentiation. In conclusion, nontumorigenic basal cell lines have intrinsic capacity for EMT, but a mesenchymal-like phenotype does not correlate with the acquisition of global stem cell/progenitor features. Based on our findings, we propose that EMT in normal basal cells and claudin-low breast cancers reflects aberrant/incomplete myoepithelial differentiation.", "title": "Epithelial and mesenchymal subpopulations within normal basal breast cell lines exhibit distinct stem cell/progenitor properties." }, { "docid": "164189", "text": "Replication origins are licensed by loading MCM2-7 hexamers before entry into S phase. However, only ∼10% of licensed origins are normally used in S phase, with the others remaining dormant. When fork progression is inhibited, dormant origins initiate nearby to ensure that all of the DNA is eventually replicated. In apparent contrast, replicative stress activates ataxia telangiectasia and rad-3-related (ATR) and Chk1 checkpoint kinases that inhibit origin firing. In this study, we show that at low levels of replication stress, ATR/Chk1 predominantly suppresses origin initiation by inhibiting the activation of new replication factories, thereby reducing the number of active factories. At the same time, inhibition of replication fork progression allows dormant origins to initiate within existing replication factories. The inhibition of new factory activation by ATR/Chk1 therefore redirects replication toward active factories where forks are inhibited and away from regions that have yet to start replication. This minimizes the deleterious consequences of fork stalling and prevents similar problems from arising in unreplicated regions of the genome.", "title": "Chk1 inhibits replication factory activation but allows dormant origin firing in existing factories" }, { "docid": "34760396", "text": "The fly Musca sorbens Wiedemann (Diptera: Muscidae) apparently transmits Chlamydia trachomatis, causing human trachoma. The literature indicates that M. sorbens breeds predominantly in isolated human faeces on the soil surface, but not in covered pit latrines. We sought to identify breeding media of M. sorbens in a rural Gambian village endemic for trachoma. Test breeding media were presented for oviposition on soil-filled buckets and monitored for adult emergence. Musca sorbens emerged from human (6/9 trials), calf (3/9), cow (3/9), dog (2/9) and goat (1/9) faeces, but not from horse faeces, composting kitchen scraps or a soil control (0/9 of each). After adjusting for mass of medium, the greatest number of flies emerged from human faeces (1426 flies/kg). Median time for emergence was 9 (inter quartile range = 8-9.75) days post-oviposition. Of all flies emerging from faeces 81% were M. sorbens. Male and female flies emerging from human faeces were significantly larger than those from other media, suggesting that they would be more fecund and live longer than smaller flies from other sources. Female flies caught from children's eyes were of a similar size to those from human faeces, but significantly larger than those from other media. We consider that human faeces are the best larval medium for M. sorbens, although some breeding also occurs in animal faeces. Removal of human faeces from the environment, through the provision of basic sanitation, is likely to greatly reduce fly density, eye contact and hence trachoma transmission, but if faeces of other animals are present M. sorbens will persist.", "title": "Human and other faeces as breeding media of the trachoma vector Musca sorbens." }, { "docid": "25419778", "text": "Cellular senescence is a fundamental mechanism by which cells remain metabolically active yet cease dividing and undergo distinct phenotypic alterations, including upregulation of p16Ink4a , profound secretome changes, telomere shortening, and decondensation of pericentromeric satellite DNA. Because senescent cells accumulate in multiple tissues with aging, these cells and the dysfunctional factors they secrete, termed the senescence-associated secretory phenotype (SASP), are increasingly recognized as promising therapeutic targets to prevent age-related degenerative pathologies, including osteoporosis. However, the cell type(s) within the bone microenvironment that undergoes senescence with aging in vivo has remained poorly understood, largely because previous studies have focused on senescence in cultured cells. Thus in young (age 6 months) and old (age 24 months) mice, we measured senescence and SASP markers in vivo in highly enriched cell populations, all rapidly isolated from bone/marrow without in vitro culture. In both females and males, p16Ink4a expression by real-time quantitative polymerase chain reaction (rt-qPCR) was significantly higher with aging in B cells, T cells, myeloid cells, osteoblast progenitors, osteoblasts, and osteocytes. Further, in vivo quantification of senescence-associated distension of satellites (SADS), ie, large-scale unraveling of pericentromeric satellite DNA, revealed significantly more senescent osteocytes in old compared with young bone cortices (11% versus 2%, p < 0.001). In addition, primary osteocytes from old mice had sixfold more (p < 0.001) telomere dysfunction-induced foci (TIFs) than osteocytes from young mice. Corresponding with the age-associated accumulation of senescent osteocytes was significantly higher expression of multiple SASP markers in osteocytes from old versus young mice, several of which also showed dramatic age-associated upregulation in myeloid cells. These data show that with aging, a subset of cells of various lineages within the bone microenvironment become senescent, although senescent myeloid cells and senescent osteocytes predominantly develop the SASP. Given the critical roles of osteocytes in orchestrating bone remodeling, our findings suggest that senescent osteocytes and their SASP may contribute to age-related bone loss. © 2016 American Society for Bone and Mineral Research.", "title": "Identification of Senescent Cells in the Bone Microenvironment." }, { "docid": "86326468", "text": "The mucin profiles of the gastric mucosa in Lundehunds suffering from intestinal lymphangiectasia were examined and compared to the mucin profiles in control dogs from other breeds. A previous study performed on this material had shown that all examined Lundehunds had gastritis and about 30% had gastric carcinoma. Neutral and acid mucins were identified using the periodic acid-Schiff (PAS) and Alcian blue (pH 2.5) periodic acid-Schiff (AB-PAS) methods. The acid mucins were divided into sialomucins and sulfomucins based on their reaction with high-iron diamine Alcian blue, pH 2.5 (HID-AB). In Lundehunds with chronic atrophic gastritis in the fundic and body regions the surface and foveolar epithelium showed a predominantly normal mucin profile although some Lundehunds had a reduced mucin content. The mucous neck cells extended from below the gastric foveolae towards the muscularis mucosae. Morphometric examination showed that the abnormal presence of mucous neck cells occupied 41% of the height of the gastric mucosa in Lundehunds compared to only 19% in the control dogs (p<0.05). Of the four Lundehunds with gastric carcinoma, two possessed neoplastic cells that contained minimal or no mucins. The amount and type of mucin in the neoplastic cells of the remaining two Lundehunds varied both between individuals and within a neoplasm. This study shows that the abnormal presence of mucous neck cells and the associated pseudopyloric metaplasia comprised the predominant changes in the gastric mucin profiles of Lundehunds.", "title": "Gastropathies in the Lundehund" } ]

[ { "docid": "18231807", "text": "Chimeric antigen receptors (CARs) targeting CD19 have mediated dramatic antitumor responses in hematologic malignancies, but tumor regression has rarely occurred using CARs targeting other antigens. It remains unknown whether the impressive effects of CD19 CARs relate to greater susceptibility of hematologic malignancies to CAR therapies, or superior functionality of the CD19 CAR itself. We show that tonic CAR CD3-ζ phosphorylation, triggered by antigen-independent clustering of CAR single-chain variable fragments, can induce early exhaustion of CAR T cells that limits antitumor efficacy. Such activation is present to varying degrees in all CARs studied, except the highly effective CD19 CAR. We further determine that CD28 costimulation augments, whereas 4-1BB costimulation reduces, exhaustion induced by persistent CAR signaling. Our results provide biological explanations for the antitumor effects of CD19 CARs and for the observations that CD19 CAR T cells incorporating the 4-1BB costimulatory domain are more persistent than those incorporating CD28 in clinical trials.", "title": "4-1BB Costimulation Ameliorates T Cell Exhaustion Induced by Tonic Signaling of Chimeric Antigen Receptors" } ]

[ { "docid": "35651106", "text": "Efficient T cell activation requires both TCR signals and costimulatory signals. CD28 is one of the molecules that provide costimulatory signals for T cells. We used mice deficient in CD28 expression (CD28-/- mice) to analyze the role of CD28 in the immune response against the intracellular bacterium Salmonella typhimurium, the causative agent of murine typhoid fever. CD28-/- mice were highly susceptible to infection with wild-type S. typhimurium and even failed to control infection with attenuated aroA- S. typhimurium. More detailed analysis revealed that CD28-/- animals did not mount a T-dependent Ab response and were highly impaired in the production of IFN-gamma. Thus, CD28 cosignaling is crucial for immunity against S. typhimurium. To our knowledge, this is the first report describing an essential role for CD28 in protective immunity against an intracellular microbial pathogen.", "title": "Critical role of CD28 in protective immunity against Salmonella typhimurium." }, { "docid": "2462673", "text": "Activation of self-reactive T cells and their trafficking to target tissues leads to autoimmune organ destruction. Mice lacking the co-inhibitory receptor cytotoxic T lymphocyte antigen-4 (CTLA-4) develop fatal autoimmunity characterized by lymphocytic infiltration into nonlymphoid tissues. Here, we demonstrate that the CD28 co-stimulatory pathway regulates the trafficking of self-reactive Ctla4(-/-) T cells to tissues. Concurrent ablation of the CD28-activated Tec family kinase ITK does not block spontaneous T cell activation but instead causes self-reactive Ctla4(-/-) T cells to accumulate in secondary lymphoid organs. Despite excessive spontaneous T cell activation and proliferation in lymphoid organs, Itk(-/-); Ctla4(-/-) mice are otherwise healthy, mount antiviral immune responses and exhibit a long lifespan. We propose that ITK specifically licenses autoreactive T cells to enter tissues to mount destructive immune responses. Notably, ITK inhibitors mimic the null mutant phenotype and also prevent pancreatic islet infiltration by diabetogenic T cells in mouse models of type 1 diabetes, highlighting their potential utility for the treatment of human autoimmune disorders.", "title": "CD28 and ITK signals regulate autoreactive T cell trafficking" }, { "docid": "40473317", "text": "In this report, we demonstrate that CD28(-/-) mice are severely impaired in the initial expansion of D(b)/NP366-374-specific CD8 T cells in response to influenza virus infection, whereas 4-1BB ligand (4-1BBL)(-/-) mice show no defect in primary T cell expansion to influenza virus. In contrast, 4-1BBL(-/-) mice show a decrease in D(b)/NP366-374-specific T cells late in the primary response. Upon secondary challenge with influenza virus, 4-1BBL(-/-) mice show a decrease in the number of D(b)/NP366-374-specific T cells compared to wild-type mice such that the level of the CD8 T cell expansion during the in vivo secondary response is reduced to the level of a primary response, with concomitant reduction of CTL effector function. In contrast, Ab responses, as well as secondary CD4 T cell responses, to influenza are unaffected by 4-1BBL deficiency. Thus, CD28 is critical for initial T cell expansion, whereas 4-1BB/4-1BBL signaling affects T cell numbers much later in the response and is essential for the survival and/or responsiveness of the memory CD8 T cell pool.", "title": "Temporal segregation of 4-1BB versus CD28-mediated costimulation: 4-1BB ligand influences T cell numbers late in the primary response and regulates the size of the T cell memory response following influenza infection." }, { "docid": "28006126", "text": "CD28 is one of the most important costimulatory receptors necessary for full T lymphocyte activation. The CD28 receptor can enhance T cell antigen receptor (TCR) signals, as well as deliver independent signals. Indeed, CD28 engagement by B7 can generate TCR-independent signals leading to IkappaB kinase and NF-kappaB activation. Here we demonstrate that the TCR-independent CD28 signal leads to the selective transcription of survival (Bcl-xL) and inflammatory (IL-8 and B cell activation factor, but not proliferative (IL-2), genes, in a NF-kappaB-dependent manner. CD28-stimulated T cells actively secrete IL-8, and Bcl-xL up-regulation protects T cells from radiation-induced apoptosis. The transcription of CD28-induced genes is mediated by the specific recruitment of RelA and p52 NF-kappaB subunits to target promoters. In contrast, p50 and c-Rel, which preferentially bind NF-kappaB sites on the IL-2 gene promoter after anti-CD3 stimulation, are not involved. Thus, we identify CD28 as a key regulator of genes important for both survival and inflammation.", "title": "CD28 delivers a unique signal leading to the selective recruitment of RelA and p52 NF-kappaB subunits on IL-8 and Bcl-xL gene promoters." }, { "docid": "13868795", "text": "Ligation of the CD28 receptor on T cells provides a critical second signal alongside T cell receptor (TCR) ligation for naive T cell activation. Here, we discuss the expression, structure, and biochemistry of CD28 and its ligands. CD28 signals play a key role in many T cell processes, including cytoskeletal remodeling, production of cytokines, survival, and differentiation. CD28 ligation leads to unique epigenetic, transcriptional, and post-translational changes in T cells that cannot be recapitulated by TCR ligation alone. We discuss the function of CD28 and its ligands in both effector and regulatory T cells. CD28 is critical for regulatory T cell survival and the maintenance of immune homeostasis. We outline the roles that CD28 and its family members play in human disease and we review the clinical efficacy of drugs that block CD28 ligands. Despite the centrality of CD28 and its family members and ligands to immune function, many aspects of CD28 biology remain unclear. Translation of a basic understanding of CD28 function into immunomodulatory therapeutics has been uneven, with both successes and failures. Such real-world results might stem from multiple factors, including complex receptor-ligand interactions among CD28 family members, differences between the mouse and human CD28 families, and cell-type specific roles of CD28 family members.", "title": "CD28 Costimulation: From Mechanism to Therapy." }, { "docid": "8038329", "text": "Although the role of CD28-B7 interaction in the activation of naive T cells is well established, its importance in the generation and maintenance of T cell memory is not well understood. In this study, we examined the requirement for CD28-B7 interactions in primary T cell activation and immune memory. Ag-specific CD8 T cell responses were compared between wild-type (+/+) and CD28-deficient (CD28(-/-)) mice following an acute infection with lymphocytic choriomeningitis virus (LCMV). During the primary response, there was a substantial activation and expansion of LCMV-specific CD8 T cells in both +/+ and CD28(-/-) mice. However, the magnitude of the primary CD8 T cell response to both dominant and subdominant LCMV CTL epitopes was approximately 2- to 3-fold lower in CD28(-/-) mice compared with +/+ mice; the lack of CD28-mediated costimulation did not lead to preferential suppression of CD8 T cell responses to the weaker subdominant epitopes. As seen in CD28(-/-) mice, blockade of B7-mediated costimulation by CTLA4-Ig treatment of +/+ mice also resulted in a 2-fold reduction in the anti-LCMV CD8 T cell responses. Loss of CD28/B7 interactions did not significantly affect the generation and maintenance of CD8 T cell memory; the magnitude of CD8 T cell memory was approximately 2-fold lower in CD28(-/-) mice as compared with +/+ mice. Further, in CD28(-/-) mice, LCMV-specific memory CD8 T cells showed normal homeostatic proliferation in vivo and also conferred protective immunity. Therefore, CD28 signaling is not necessary for the proliferative renewal and maintenance of memory CD8 T cells.", "title": "Role of CD28-B7 interactions in generation and maintenance of CD8 T cell memory." }, { "docid": "14657344", "text": "Leishmania mexicana (Lm) causes localized (LCL) and diffuse (DCL) cutaneous leishmaniasis. DCL patients have a poor cellular immune response leading to chronicity. It has been proposed that CD8 T lymphocytes (CD8) play a crucial role in infection clearance, although the role of CD8 cytotoxicity in disease control has not been elucidated. Lesions of DCL patients have been shown to harbor low numbers of CD8, as compared to patients with LCL, and leishmanicidal treatment restores CD8 numbers. The marked response of CD8 towards Leishmania parasites led us to analyze possible functional differences between CD8 from patients with LCL and DCL. We compared IFNγ production, antigen-specific proliferation, and cytotoxicity of CD8 purified from PBMC against autologous macrophages (MO) infected with Leishmania mexicana (MOi). Additionally, we analyzed tissue biopsies from both groups of patients for evidence of cytotoxicity associated with apoptotic cells in the lesions. We found that CD8 cell of DCL patients exhibited low cytotoxicity, low antigen-specific proliferation and low IFNγ production when stimulated with MOi, as compared to LCL patients. Additionally, DCL patients had significantly less TUNEL+ cells in their lesions. These characteristics are similar to cellular \"exhaustion\" described in chronic infections. We intended to restore the functional capacity of CD8 cells of DCL patients by preincubating them with TLR2 agonists: Lm lipophosphoglycan (LPG) or Pam3Cys. Cytotoxicity against MOi, antigen-specific proliferation and IFNγ production were restored with both stimuli, whereas PD-1 (a molecule associated with cellular exhaustion) expression, was reduced. Our work suggests that CD8 response is associated with control of Lm infection in LCL patients and that chronic infection in DCL patients leads to a state of CD8 functional exhaustion, which could facilitate disease spread. This is the first report that shows the presence of functionally exhausted CD8 T lymphocytes in DCL patients and, additionally, that pre-stimulation with TLR2 ligands can restore the effector mechanisms of CD8 T lymphocytes from DCL patients against Leishmania mexicana-infected macrophages.", "title": "CD8 Cells of Patients with Diffuse Cutaneous Leishmaniasis Display Functional Exhaustion: The Latter Is Reversed, In Vitro, by TLR2 Agonists" }, { "docid": "18758057", "text": "Direct molecular imaging of nano-spatial relationship between T cell receptor (TCR)/CD3 and CD4 or CD8 co-receptor before and after activation of a primary T cell has not been reported. We have recently innovated application of near-field scanning optical microscopy (NSOM) and immune-labeling quantum dots (QD) to image Ag-specific TCR response during in vivo clonal expansion, and now up-graded the NSOM/QD-based nanotechnology through dipole-polarization and dual-color imaging. Using this imaging system scanning cell-membrane molecules at a best-optical lateral resolution, we demonstrated that CD3, CD4 or CD8 molecules were distinctly distributed as single QD-bound molecules or nano-clusters equivalent to 2-4 QD fluorescence-intensity/size on cell-membrane of un-stimulated primary T cells, and approximately 6-10% of CD3 were co-clustering with CD4 or CD8 as 70-110 nm nano-clusters without forming nano-domains. The ligation of TCR/CD3 on CD4 or CD8 T cells led to CD3 nanoscale co-clustering or interaction with CD4 or CD8 co-receptors forming 200-500 nm nano-domains or >500 nm micro-domains. Such nano-spatial co-clustering of CD3 and CD4 or CD3 and CD8 appeared to be an intrinsic event of TCR/CD3 ligation, not purely limited to MHC engagement, and be driven by Lck phosphorylation. Importantly, CD28 co-stimulation remarkably enhanced TCR/CD3 nanoscale co-clustering or interaction with CD4 co-receptor within nano- or micro-domains on the membrane. In contrast, CD28 co-stimulation did not enhance CD8 clustering or CD3-CD8 co-clustering in nano-domains although it increased molecular number and density of CD3 clustering in the enlarged nano-domains. These nanoscale findings provide new insights into TCR/CD3 interaction with CD4 or CD8 co-receptor in T-cell activation.", "title": "NSOM/QD-Based Direct Visualization of CD3-Induced and CD28-Enhanced Nanospatial Coclustering of TCR and Coreceptor in Nanodomains in T Cell Activation" }, { "docid": "10562341", "text": "The activation of T cells is the fundamental on switch for the adaptive immune system. Ca2+ signaling is essential for T cell activation and starts as initial, short-lived, localized Ca2+ signals. The second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) forms rapidly upon T cell activation and stimulates early Ca2+ signaling. We developed a high-resolution imaging technique using multiple fluorescent Ca2+ indicator dyes to characterize these early signaling events and investigate the channels involved in NAADP-dependent Ca2+ signals. In the first seconds of activation of either primary murine T cells or human Jurkat cells with beads coated with an antibody against CD3, we detected Ca2+ signals with diameters close to the limit of detection and that were close to the activation site at the plasma membrane. In Jurkat cells in which the ryanodine receptor (RyR) was knocked down or in primary T cells from RyR1−/− mice, either these early Ca2+ signals were not detected or the number of signals was markedly reduced. Local Ca2+ signals observed within 20 ms upon microinjection of Jurkat cells with NAADP were also sensitive to RyR knockdown. In contrast, TRPM2 (transient receptor potential channel, subtype melastatin 2), a potential NAADP target channel, was not required for the formation of initial Ca2+ signals in primary T cells. Thus, through our high-resolution imaging method, we characterized early Ca2+ release events in T cells and obtained evidence for the involvement of RyR and NAADP in such signals.", "title": "Frontrunners of T cell activation: Initial, localized Ca2+ signals mediated by NAADP and the type 1 ryanodine receptor" }, { "docid": "9955779", "text": "Combining DNA-demethylating agents (DNA methyltransferase inhibitors [DNMTis]) with histone deacetylase inhibitors (HDACis) holds promise for enhancing cancer immune therapy. Herein, pharmacologic and isoform specificity of HDACis are investigated to guide their addition to a DNMTi, thus devising a new, low-dose, sequential regimen that imparts a robust anti-tumor effect for non-small-cell lung cancer (NSCLC). Using in-vitro-treated NSCLC cell lines, we elucidate an interferon α/β-based transcriptional program with accompanying upregulation of antigen presentation machinery, mediated in part through double-stranded RNA (dsRNA) induction. This is accompanied by suppression of MYC signaling and an increase in the T cell chemoattractant CCL5. Use of this combination treatment schema in mouse models of NSCLC reverses tumor immune evasion and modulates T cell exhaustion state towards memory and effector T cell phenotypes. Key correlative science metrics emerge for an upcoming clinical trial, testing enhancement of immune checkpoint therapy for NSCLC.", "title": "Epigenetic Therapy Ties MYC Depletion to Reversing Immune Evasion and Treating Lung Cancer" }, { "docid": "40349336", "text": "Developmental abnormalities, cancer, and premature aging each have been linked to defects in the DNA damage response (DDR). Mutations in the ATR checkpoint regulator cause developmental defects in mice (pregastrulation lethality) and humans (Seckel syndrome). Here we show that eliminating ATR in adult mice leads to defects in tissue homeostasis and the rapid appearance of age-related phenotypes, such as hair graying, alopecia, kyphosis, osteoporosis, thymic involution, fibrosis, and other abnormalities. Histological and genetic analyses indicate that ATR deletion causes acute cellular loss in tissues in which continuous cell proliferation is required for maintenance. Importantly, thymic involution, alopecia, and hair graying in ATR knockout mice were associated with dramatic reductions in tissue-specific stem and progenitor cells and exhaustion of tissue renewal and homeostatic capacity. In aggregate, these studies suggest that reduced regenerative capacity in adults via deletion of a developmentally essential DDR gene is sufficient to cause the premature appearance of age-related phenotypes.", "title": "Deletion of the developmentally essential gene ATR in adult mice leads to age-related phenotypes and stem cell loss." }, { "docid": "15521377", "text": "Cellular senescence is a stable form of cell-cycle arrest which is thought to limit the proliferative potential of premalignant cells [1]. The senescence phenotype was initially described by Hayflick and Moorhead in 1961 on human fibroblasts undergoing replicative exhaustion in culture [2]. It has been shown that senescence can be triggered in different cell types in response to diverse forms of cellular damage or stress (for review see [1]). Importantly, while senescence was denounced as a tissue culture phenomenon for many years, recent in vivo studies demonstrated that cellular senescence represents a potent failsafe mechanism against tumorigenesis and contributes to the cytotoxicity of certain anticancer agents (see for example [3-7]). Interestingly, senescent cells have also been observed in certain aged or damaged tissues and there is growing evidence that senescence checkpoints can affect the regenerative reserve of tissues and organismal aging [8-11]. However, senescence may also have positive effects on organ maintenance by limiting pathological responses to acute forms of injury such as fibrotic scarring in response to chemical induced liver injury [12]. Over the past years it was also shown that senescent cells can communicate with their environment by secreting a myriad of cytokines and growth factors. Interestingly, this \"senescence associated secretory phenotype (SASP)\" seems to be a double edged sword regarding tumor initiation and maintenance: i) On the one hand, it has been shown that the SASP can have pro-tumorigenic effects. In an experimental system it was shown that senescent mesenchymal cells can enhance the tumorigenicity of surrounding breast cancer cells [13]. ii) Similarly, it is possible that the SASP enhances selection of transformed cell clones in aged organ systems. It has been shown that loss of proliferative competition of non-transformed cells can accelerate leukemogenesis [14]. It remains to be seen whether aberrant secretion of cytokines and growth factors by the SASP can accelerated this process in aged and chronically damage organ systems. iii) In contrast to its pro-tumorigenic aspect, the SASP could also have anti-tumor effects. A recent study showed that in a mosaic liver cancer mouse model the activation of p53 induced senescence, an upregulation of inflammatory cytokines, and activation of innate immune responses leading to tumour cell clearance [15]. iv) In further support that the SASP could have anti-tumor activities, a series of recent papers showed that components of the SASP can stabilize the senescence cell cycle arrest via an autoregulatory feedback loop [16,17] or induces apoptosis of tumor cells [18]. In addition to its effects on tumorigenesis, the SASP could also influence tissue aging. Studies on aging telomere dysfunctional mice have provided direct experimental evidence for an in vivo activation of the SASP in response to telomere dysfunction [19]. Interestingly, this in vivo SASP provoked alterations in stem cell differentiation (skewing of hematopoiesis towards reduction in lymphopoiesis and enhancement of myelopoiesis) that are also characteristic signs of human aging. Figure 1. Different cellular stresses can induce senescence including telomere shortening, DNA damage, and oncogene activation. Senescence of tumor cells ... In light of the many possible roles o the SASP in aging and carcinogenesis, it appears to be of utmost importance to decipher regulatory pathways controlling the SASP. In a current publication, Bhaumik et al. have identified 2 microRNAs (miR-146a/b) that negatively regulate the secretion of IL-6 and IL-8 - two of the SASP [20]. The authors show that these microRNAs are up-regulated at late stages of senescence, many days after a permanent cell cycle arrest has been established. Interestingly, the inhibitory miRs are most strongly up-regulated in senescence of cell lines that show a strong SASP but not in cell lines characterized by a weak SASP. The authors propose a new concept indicating that miRs 146a and b function in a negative feedback loop preventing an over-activation of the SASP in senescent cells. The authors present some initial data suggesting that activation of this negative feedback loop involves IL-1 receptor, IRAK-1, and NFκB signalling leading to an up-regulation of miRs-146a and b. A direct proof that this proposed feedback loop suppresses over-activation of the SASP remains to be demonstrated in future studies. The authors show that blockage of IL-1-receptor signalling prevents both the up-regulation of miRs-146a and b as well as Il-6 secretion. To confirm their new concept, it would be important to show that a selective blockage of miRs-146a and b results in over-activation of the SASP. The work by Bhaumik et al. places mir-146a/b as central players to control IL-6 and IL-8 expression within the SASP. MicroRNAs are emerging therapeutic targets because their expression levels can be effectively modulated via the use of antagomirs (see for example [21]). Also, for increasing microRNA expression, microRNAs can be delivered into cellsin vivo (see for example [22]). Therefore, it will be interesting to functionally test the impact of mir-146 inhibition on tumorigenesis and aging in relevant mouse models. Such studies will be of particular interest, as recent work showed that IL-6 secretion by senescent cells is relevant for initiating and maintaining the senescene response via an autocrine loop [17]. A reduction of miR-146 could increase IL-6 levels in senescent cells, which should stabilize the senescence program and reduce the risk of malignant transformation. Furthermore, it can be speculated that reduction of mir-146 a/b will increase NfκB activation via IRAK1. As NfκB is modulating the expression of various inflammation associated genes, this may also lead to increased clearance of senescent tumor cells by the innate immune system. However, it should be mentioned that Il-6 secreted by senescent cells can also act as a mitogen for surrounding cells, thus potentially increasing the risk of malignant transformation [13,17]. Besides its function in SASP modulation, miR-146 was also reported to target the mRNAs of the BRCA1 and BRCA2 tumor suppressors. In a recent study a G to C polymorphism in miR-146, which leads to an increased processing and release of the mature microRNA, can predict an early onset of breast cancer [23]. Taken together, the study of Bhaumik et al. opens an interesting new research area dealing with the gene regulatory mechanisms that control activation of the SASP. Given the diverse roles of the SASP in modulating tumor progression, immune surveillance of damaged cells, and the stabilization of the senescence arrest itself, it will be of great interest to analyse the influence of SASP regulatory pathways during aging and cancer.", "title": "Keeping your senescent cells under control" }, { "docid": "2388819", "text": "The low number of CD4+ CD25+ regulatory T cells (Tregs), their anergic phenotype, and diverse antigen specificity present major challenges to harnessing this potent tolerogenic population to treat autoimmunity and transplant rejection. In this study, we describe a robust method to expand antigen-specific Tregs from autoimmune-prone nonobese diabetic mice. Purified CD4+ CD25+ Tregs were expanded up to 200-fold in less than 2 wk in vitro using a combination of anti-CD3, anti-CD28, and interleukin 2. The expanded Tregs express a classical cell surface phenotype and function both in vitro and in vivo to suppress effector T cell functions. Most significantly, small numbers of antigen-specific Tregs can reverse diabetes after disease onset, suggesting a novel approach to cellular immunotherapy for autoimmunity.", "title": "In Vitro–expanded Antigen-specific Regulatory T Cells Suppress Autoimmune Diabetes" }, { "docid": "38502066", "text": "Thymic-derived natural T regulatory cells (Tregs) are characterized by functional and phenotypic heterogeneity. Recently, a small fraction of peripheral Tregs has been shown to express Klrg1, but it remains unclear as to what extent Klrg1 defines a unique Treg subset. In this study, we show that Klrg1(+) Tregs represent a terminally differentiated Treg subset derived from Klrg1(-) Tregs. This subset is a recent Ag-responsive and highly activated short-lived Treg population that expresses enhanced levels of Treg suppressive molecules and that preferentially resides within mucosal tissues. The development of Klrg1(+) Tregs also requires extensive IL-2R signaling. This activity represents a distinct function for IL-2, independent from its contribution to Treg homeostasis and competitive fitness. These and other properties are analogous to terminally differentiated short-lived CD8(+) T effector cells. Our findings suggest that an important pathway driving Ag-activated conventional T lymphocytes also operates for Tregs.", "title": "IL-2 receptor signaling is essential for the development of Klrg1+ terminally differentiated T regulatory cells." }, { "docid": "36816310", "text": "Sorting signals for cargo selection into coated vesicles are usually in the form of short linear motifs. Three motifs for clathrin-mediated endocytosis have been identified: YXXPhi, [D/E]XXXL[L/I] and FXNPXY. To search for new endocytic motifs, we made a library of CD8 chimeras with random sequences in their cytoplasmic tails, and used a novel fluorescence-activated cell sorting (FACS)-based assay to select for endocytosed constructs. Out of the five tails that were most efficiently internalized, only one was found to contain a conventional motif. Two contain dileucine-like sequences that appear to be variations on the [D/E]XXXL[L/I] motif. Another contains a novel internalization signal, YXXXPhiN, which is able to function in cells expressing a mutant mu2 that cannot bind YXXPhi, indicating that it is not a variation on the YXXPhi motif. Similar sequences are present in endogenous proteins, including a functional YXXXPhiN (in addition to a classical YXXPhi) in cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Thus, the repertoire of endocytic motifs is more extensive than the three well-characterized sorting signals.", "title": "A Screen for Endocytic Motifs" }, { "docid": "14644164", "text": "TLR sense microbial infections, and control activation of immune responses. Dendritic cells, macrophages, and B lymphocytes express TLR and the TLR-signaling adaptor protein MyD88. The impact of TLR-activated B cells on T cell-mediated inflammation is unknown. In this study, we have used mice carrying B cell-restricted deficiencies in MyD88 or in distinct TLR to examine the impact of TLR-activated B cells on a T cell-mediated autoimmune disease, experimental autoimmune encephalomyelitis (EAE). We demonstrate that TLR-signaling in B cells suppresses inflammatory T cell responses (both Th1 and Th17), and stimulates recovery from EAE. Only certain TLR are required on B cells for resolution of EAE, and these are dispensable for disease initiation, indicating that a category of TLR agonists preferentially triggers a suppressive function in B cells and thereby limits autoimmune disease. The TLR agonists controlling the regulatory function of B cells are provided by components of Mycobacterium tuberculosis present in the adjuvant. Thus, MyD88 signaling in B cells antagonizes MyD88 signaling in other cells, which drives differentiation of Th17 cells and is required for induction of EAE. Altogether, our data indicate that B cells link recognition of microbial products via TLR to suppression of a T cell-mediated autoimmune disease.", "title": "TLR-activated B cells suppress T cell-mediated autoimmunity." }, { "docid": "6163801", "text": "Cytolytic granules mediate killing of virus-infected cells by cytotoxic T lymphocytes. We show here that the granules can take long or short paths to the secretory domain. Both paths utilized the same intracellular molecular events, which have different spatial and temporal arrangements and are regulated by the kinetics of Ca(2+)-mediated signaling. Rapid signaling caused swift granule concentration near the microtubule-organizing center (MTOC) and subsequent delivery by the polarized MTOC directly to the secretory domain-the shortest path. Indolent signaling led to late recruitment of granules that moved along microtubules to the periphery of the synapse and then moved tangentially to fuse at the outer edge of the secretory domain-a longer path. The short pathway is associated with faster granule release and more efficient killing than the long pathway. Thus, the kinetics of early signaling regulates the quality of the T cell cytolytic response.", "title": "Kinetics of early T cell receptor signaling regulate the pathway of lytic granule delivery to the secretory domain." }, { "docid": "39539647", "text": "IL-12 has been identified as a major cytokine influencing the differentiation of CD4 cells to a Th1 phenotype, whereas a role for IFN-gamma is controversial. We investigated the interrelationship between IL-12 and IFN-gamma in promoting Th1 responses using naive CD4 cells reactive with pigeon cytochrome c from TCR transgenics and memory CD4 cells derived by in vivo priming with KLH. Without exogenous rIL-12 or rIFN-gamma, primary and memory effectors induced by Ag or anti-CD3 and anti-CD28 secreted variable levels of IL-2 and IFN-gamma. The level of IFN-gamma secreted by effectors correlated with endogenous IFN-gamma produced in primary cultures, and anti-IFN-gamma largely inhibited the development of effectors producing IFN-gamma. With optimal TCR stimulation and costimulation, endogenous IFN-gamma, without IL-12, was sufficient to elicit Th1 cells via an autocrine mechanism, whereas with suboptimal stimulation, exogenous rIFN-gamma or rIL-12 was required for Th1 development. However, rIL-12 was more effective than rIFN-gamma, partially because rIL-12 greatly enhanced autocrine production of IFN-gamma, and optimal development of the Th1 phenotype was mediated by the synergistic actions of both cytokines. Thus, both IFN-gamma and IL-12 can independently regulate Th1 development, but because of IFN-gamma-mediated feedback, their relative contributions are determined by the conditions of T cell stimulation. The extent of differentiation to a Th1 phenotype may, therefore, depend on the availability of both APC-derived IL-12 and autocrine IFN-gamma consequent to the overall strength of T cell stimulation.", "title": "A direct role for IFN-gamma in regulation of Th1 cell development." }, { "docid": "13398997", "text": "The CD28/cytotoxic T-lymphocyte antigen 4 (CTLA-4)blocker belatacept selectively inhibits alloreactive T cell responses but is associated with a high incidence of acute rejection following renal transplantation,which led us to investigate the etiology of belatacept–resistant graft rejection. T cells can differentiate into functionally distinct subsets of memory T cellsthat collectively enable protection against diverse classes of pathogens and can cross-react with allogeneicantigen and mediate graft rejection. T helper 17(Th17) cells are a pro-inflammatory CD4+ lineage that provides immunity to pathogens and are pathogenic in autoimmune disease. We found that T helper 1 (Th1)and Th17 memory compartments contained a similar frequency of divided cells following allogeneic stimulation. Compared to Th1 cells, Th17 memory cells expressed significantly higher levels of the coinhibitory molecule CTLA-4. Stimulation in the presence of belatacept inhibited Th1 responses but augmented Th17 cells due to greater sensitivity to coinhibition by CTLA-4. Th17 cells from renal transplant recipients were resistant to ex vivo CD28/CTLA-4 blockade with belatacept, and an elevated frequency of Th17 memory cells was associated with acute rejection during belatacept therapy. These data highlight important differences in costimulatory and coinhibitory requirements of CD4+ memory subsets, and demonstrate that the heterogeneity of pathogen-derived memory has implications for immunomodulation strategies.", "title": "High CTLA-4 expression on Th17 cells results in increased sensitivity to CTLA-4 coinhibition and resistance to belatacept." } ]

[ { "docid": "2462673", "text": "Activation of self-reactive T cells and their trafficking to target tissues leads to autoimmune organ destruction. Mice lacking the co-inhibitory receptor cytotoxic T lymphocyte antigen-4 (CTLA-4) develop fatal autoimmunity characterized by lymphocytic infiltration into nonlymphoid tissues. Here, we demonstrate that the CD28 co-stimulatory pathway regulates the trafficking of self-reactive Ctla4(-/-) T cells to tissues. Concurrent ablation of the CD28-activated Tec family kinase ITK does not block spontaneous T cell activation but instead causes self-reactive Ctla4(-/-) T cells to accumulate in secondary lymphoid organs. Despite excessive spontaneous T cell activation and proliferation in lymphoid organs, Itk(-/-); Ctla4(-/-) mice are otherwise healthy, mount antiviral immune responses and exhibit a long lifespan. We propose that ITK specifically licenses autoreactive T cells to enter tissues to mount destructive immune responses. Notably, ITK inhibitors mimic the null mutant phenotype and also prevent pancreatic islet infiltration by diabetogenic T cells in mouse models of type 1 diabetes, highlighting their potential utility for the treatment of human autoimmune disorders.", "title": "CD28 and ITK signals regulate autoreactive T cell trafficking" } ]

[ { "docid": "28006126", "text": "CD28 is one of the most important costimulatory receptors necessary for full T lymphocyte activation. The CD28 receptor can enhance T cell antigen receptor (TCR) signals, as well as deliver independent signals. Indeed, CD28 engagement by B7 can generate TCR-independent signals leading to IkappaB kinase and NF-kappaB activation. Here we demonstrate that the TCR-independent CD28 signal leads to the selective transcription of survival (Bcl-xL) and inflammatory (IL-8 and B cell activation factor, but not proliferative (IL-2), genes, in a NF-kappaB-dependent manner. CD28-stimulated T cells actively secrete IL-8, and Bcl-xL up-regulation protects T cells from radiation-induced apoptosis. The transcription of CD28-induced genes is mediated by the specific recruitment of RelA and p52 NF-kappaB subunits to target promoters. In contrast, p50 and c-Rel, which preferentially bind NF-kappaB sites on the IL-2 gene promoter after anti-CD3 stimulation, are not involved. Thus, we identify CD28 as a key regulator of genes important for both survival and inflammation.", "title": "CD28 delivers a unique signal leading to the selective recruitment of RelA and p52 NF-kappaB subunits on IL-8 and Bcl-xL gene promoters." }, { "docid": "35651106", "text": "Efficient T cell activation requires both TCR signals and costimulatory signals. CD28 is one of the molecules that provide costimulatory signals for T cells. We used mice deficient in CD28 expression (CD28-/- mice) to analyze the role of CD28 in the immune response against the intracellular bacterium Salmonella typhimurium, the causative agent of murine typhoid fever. CD28-/- mice were highly susceptible to infection with wild-type S. typhimurium and even failed to control infection with attenuated aroA- S. typhimurium. More detailed analysis revealed that CD28-/- animals did not mount a T-dependent Ab response and were highly impaired in the production of IFN-gamma. Thus, CD28 cosignaling is crucial for immunity against S. typhimurium. To our knowledge, this is the first report describing an essential role for CD28 in protective immunity against an intracellular microbial pathogen.", "title": "Critical role of CD28 in protective immunity against Salmonella typhimurium." }, { "docid": "7343711", "text": "Successful cancer treatment requires understanding host immune response against tumor cells. PD-1 belongs to the CD28 superfamily of receptors that work as “checkpoints” of immune activation. PD-1 maintains immune self-tolerance to prevent autoimmunity and controls T-cell reaction during infection to prevent excessive tissue damage. Tumor cells that arise from normal tissue acquire mutations that can be targeted by lymphocytes. Accumulating lines of evidence suggest that tumor cells evade host immune attack by expressing physiological PD-1 ligands and stimulating PD-1 on the lymphocytes. Based on this idea, researchers have successfully demonstrated that systemic administration of monoclonal antibodies that inhibit the binding of PD-1 to the ligands reactivated T cells and augmented the anti-cancer immune response. In this review, I summarize the basics of T-cell biology and its regulation by PD-1 and discuss the current understanding and questions about this multifaceted molecule.", "title": "Basics of PD-1 in self-tolerance, infection, and cancer immunity" }, { "docid": "32101982", "text": "The transcription factor Krüppel-like factor 2 (KLF2) is critical for normal trafficking of T lymphocytes, but its role in B cells is unclear. We report that B cell-specific KLF2 deficiency leads to decreased expression of the trafficking molecules CD62L and β7-integrin, yet expression of sphingosine-1 phosphate receptor 1 (which is a critical target of KLF2 in T cells) was, unexpectedly, minimally altered. Unexpectedly, Klf2 deletion led to a drastic reduction in the B1 B-cell pool and a substantial increase in transitional and marginal zone B-cell numbers. In addition, we observed that KLF2-deficient B cells showed increased apoptosis and impaired proliferation after B-cell receptor cross-linking. Gene expression analysis indicated that KLF2-deficient follicular B cells display numerous characteristics shared by normal marginal zone B cells, including reduced expression of several signaling molecules that may contribute to defective activation of these cells. Hence, our data indicate that KLF2 plays a critical role in dictating normal subset differentiation and functional reactivity of mature B cells.", "title": "Krüppel-like factor 2 (KLF2) regulates B-cell reactivity, subset differentiation, and trafficking molecule expression." }, { "docid": "18488986", "text": "The expression of melanoma-associated antigens (MAA) being limited to normal melanocytes and melanomas, MAAs are ideal targets for immunotherapy and melanoma vaccines. As MAAs are derived from self, immune responses to these may be limited by thymic tolerance. The extent to which self-tolerance prevents efficient immune responses to MAAs remains unknown. The autoimmune regulator (AIRE) controls the expression of tissue-specific self-antigens in thymic epithelial cells (TECs). The level of antigens expressed in the TECs determines the fate of auto-reactive thymocytes. Deficiency in AIRE leads in both humans (APECED patients) and mice to enlarged autoreactive immune repertoires. Here we show increased IgG levels to melanoma cells in APECED patients correlating with autoimmune skin features. Similarly, the enlarged T cell repertoire in AIRE(-/-) mice enables them to mount anti-MAA and anti-melanoma responses as shown by increased anti-melanoma antibodies, and enhanced CD4(+) and MAA-specific CD8(+) T cell responses after melanoma challenge. We show that thymic expression of gp100 is under the control of AIRE, leading to increased gp100-specific CD8(+) T cell frequencies in AIRE(-/-) mice. TRP-2 (tyrosinase-related protein), on the other hand, is absent from TECs and consequently TRP-2 specific CD8(+) T cells were found in both AIRE(-/-) and AIRE(+/+) mice. This study emphasizes the importance of investigating thymic expression of self-antigens prior to their inclusion in vaccination and immunotherapy strategies.", "title": "The Immune Response to Melanoma Is Limited by Thymic Selection of Self-Antigens" }, { "docid": "13868795", "text": "Ligation of the CD28 receptor on T cells provides a critical second signal alongside T cell receptor (TCR) ligation for naive T cell activation. Here, we discuss the expression, structure, and biochemistry of CD28 and its ligands. CD28 signals play a key role in many T cell processes, including cytoskeletal remodeling, production of cytokines, survival, and differentiation. CD28 ligation leads to unique epigenetic, transcriptional, and post-translational changes in T cells that cannot be recapitulated by TCR ligation alone. We discuss the function of CD28 and its ligands in both effector and regulatory T cells. CD28 is critical for regulatory T cell survival and the maintenance of immune homeostasis. We outline the roles that CD28 and its family members play in human disease and we review the clinical efficacy of drugs that block CD28 ligands. Despite the centrality of CD28 and its family members and ligands to immune function, many aspects of CD28 biology remain unclear. Translation of a basic understanding of CD28 function into immunomodulatory therapeutics has been uneven, with both successes and failures. Such real-world results might stem from multiple factors, including complex receptor-ligand interactions among CD28 family members, differences between the mouse and human CD28 families, and cell-type specific roles of CD28 family members.", "title": "CD28 Costimulation: From Mechanism to Therapy." }, { "docid": "8038329", "text": "Although the role of CD28-B7 interaction in the activation of naive T cells is well established, its importance in the generation and maintenance of T cell memory is not well understood. In this study, we examined the requirement for CD28-B7 interactions in primary T cell activation and immune memory. Ag-specific CD8 T cell responses were compared between wild-type (+/+) and CD28-deficient (CD28(-/-)) mice following an acute infection with lymphocytic choriomeningitis virus (LCMV). During the primary response, there was a substantial activation and expansion of LCMV-specific CD8 T cells in both +/+ and CD28(-/-) mice. However, the magnitude of the primary CD8 T cell response to both dominant and subdominant LCMV CTL epitopes was approximately 2- to 3-fold lower in CD28(-/-) mice compared with +/+ mice; the lack of CD28-mediated costimulation did not lead to preferential suppression of CD8 T cell responses to the weaker subdominant epitopes. As seen in CD28(-/-) mice, blockade of B7-mediated costimulation by CTLA4-Ig treatment of +/+ mice also resulted in a 2-fold reduction in the anti-LCMV CD8 T cell responses. Loss of CD28/B7 interactions did not significantly affect the generation and maintenance of CD8 T cell memory; the magnitude of CD8 T cell memory was approximately 2-fold lower in CD28(-/-) mice as compared with +/+ mice. Further, in CD28(-/-) mice, LCMV-specific memory CD8 T cells showed normal homeostatic proliferation in vivo and also conferred protective immunity. Therefore, CD28 signaling is not necessary for the proliferative renewal and maintenance of memory CD8 T cells.", "title": "Role of CD28-B7 interactions in generation and maintenance of CD8 T cell memory." }, { "docid": "40473317", "text": "In this report, we demonstrate that CD28(-/-) mice are severely impaired in the initial expansion of D(b)/NP366-374-specific CD8 T cells in response to influenza virus infection, whereas 4-1BB ligand (4-1BBL)(-/-) mice show no defect in primary T cell expansion to influenza virus. In contrast, 4-1BBL(-/-) mice show a decrease in D(b)/NP366-374-specific T cells late in the primary response. Upon secondary challenge with influenza virus, 4-1BBL(-/-) mice show a decrease in the number of D(b)/NP366-374-specific T cells compared to wild-type mice such that the level of the CD8 T cell expansion during the in vivo secondary response is reduced to the level of a primary response, with concomitant reduction of CTL effector function. In contrast, Ab responses, as well as secondary CD4 T cell responses, to influenza are unaffected by 4-1BBL deficiency. Thus, CD28 is critical for initial T cell expansion, whereas 4-1BB/4-1BBL signaling affects T cell numbers much later in the response and is essential for the survival and/or responsiveness of the memory CD8 T cell pool.", "title": "Temporal segregation of 4-1BB versus CD28-mediated costimulation: 4-1BB ligand influences T cell numbers late in the primary response and regulates the size of the T cell memory response following influenza infection." }, { "docid": "18231807", "text": "Chimeric antigen receptors (CARs) targeting CD19 have mediated dramatic antitumor responses in hematologic malignancies, but tumor regression has rarely occurred using CARs targeting other antigens. It remains unknown whether the impressive effects of CD19 CARs relate to greater susceptibility of hematologic malignancies to CAR therapies, or superior functionality of the CD19 CAR itself. We show that tonic CAR CD3-ζ phosphorylation, triggered by antigen-independent clustering of CAR single-chain variable fragments, can induce early exhaustion of CAR T cells that limits antitumor efficacy. Such activation is present to varying degrees in all CARs studied, except the highly effective CD19 CAR. We further determine that CD28 costimulation augments, whereas 4-1BB costimulation reduces, exhaustion induced by persistent CAR signaling. Our results provide biological explanations for the antitumor effects of CD19 CARs and for the observations that CD19 CAR T cells incorporating the 4-1BB costimulatory domain are more persistent than those incorporating CD28 in clinical trials.", "title": "4-1BB Costimulation Ameliorates T Cell Exhaustion Induced by Tonic Signaling of Chimeric Antigen Receptors" }, { "docid": "40590358", "text": "The pro-drug FTY720 is undergoing phase III clinical trials for prevention of allograft rejection. After phosphorylation, FTY720 targets the G protein-coupled-sphingosine-1-phosphate receptor 1 (S1PR1) on lymphocytes, thereby inhibiting their egress from lymphoid organs and their recirculation to inflammatory sites. Potential effects on dendritic cell (DC) trafficking have not been evaluated. Here, we demonstrate the expression of all five S1PR subtypes (S1PR1-5) by murine DCs. Administration of FTY720 to C57BL/10 mice markedly reduced circulating T and B lymphocytes within 24 h, but not blood-borne DCs, which were enhanced significantly for up to 96 h, while DCs in lymph nodes and spleen were reduced. Numbers of adoptively transferred, fluorochrome-labeled syngeneic or allogeneic DCs in blood were increased significantly in FTY720-treated animals, while donor-derived DCs and allostimulatory activity for host naïve T cells within the spleen were reduced. Administration of the selective S1PR1 agonist SEW2871 significantly enhanced circulating DC numbers. Flow analysis revealed that CD11b, CD31/PECAM-1, CD54/ICAM-1 and CCR7 expression on blood-borne DCs was downregulated following FTY720 administration. Transendothelial migration of FTY720-P-treated immature DCs to the CCR7 ligand CCL19 was reduced. These novel data suggest that modulation of DC trafficking by FTY720 may contribute to its immunosuppressive effects.", "title": "The sphingosine-1-phosphate receptor agonist FTY720 modulates dendritic cell trafficking in vivo." }, { "docid": "6609935", "text": "The Drosophila melanogaster MICAL protein is essential for the neuronal growth cone machinery that functions through plexin- and semaphorin-mediated axonal signaling. Drosophila MICAL is also involved in regulating myofilament organization and synaptic structures, and serves as an actin disassembly factor downstream of plexin-mediated axonal repulsion. In mammalian cells there are three known isoforms, MICAL1, MICAL2 and MICAL3, as well as the MICAL-like proteins MICAL-L1 and MICAL-L2, but little is known of their function, and information comes almost exclusively from neural cells. In this study we show that in non-neural cells human MICALs are required for normal actin organization, and all three MICALs regulate actin stress fibers. Moreover, we provide evidence that the generation of reactive oxygen species by MICAL proteins is crucial for their actin-regulatory function. However, although MICAL1 is auto-inhibited by its C-terminal coiled-coil region, MICAL2 remains constitutively active and affects stress fibers. These data suggest differential but complementary roles for MICAL1 and MICAL2 in actin microfilament regulation.", "title": "Differential regulation of actin microfilaments by human MICAL proteins." }, { "docid": "39539647", "text": "IL-12 has been identified as a major cytokine influencing the differentiation of CD4 cells to a Th1 phenotype, whereas a role for IFN-gamma is controversial. We investigated the interrelationship between IL-12 and IFN-gamma in promoting Th1 responses using naive CD4 cells reactive with pigeon cytochrome c from TCR transgenics and memory CD4 cells derived by in vivo priming with KLH. Without exogenous rIL-12 or rIFN-gamma, primary and memory effectors induced by Ag or anti-CD3 and anti-CD28 secreted variable levels of IL-2 and IFN-gamma. The level of IFN-gamma secreted by effectors correlated with endogenous IFN-gamma produced in primary cultures, and anti-IFN-gamma largely inhibited the development of effectors producing IFN-gamma. With optimal TCR stimulation and costimulation, endogenous IFN-gamma, without IL-12, was sufficient to elicit Th1 cells via an autocrine mechanism, whereas with suboptimal stimulation, exogenous rIFN-gamma or rIL-12 was required for Th1 development. However, rIL-12 was more effective than rIFN-gamma, partially because rIL-12 greatly enhanced autocrine production of IFN-gamma, and optimal development of the Th1 phenotype was mediated by the synergistic actions of both cytokines. Thus, both IFN-gamma and IL-12 can independently regulate Th1 development, but because of IFN-gamma-mediated feedback, their relative contributions are determined by the conditions of T cell stimulation. The extent of differentiation to a Th1 phenotype may, therefore, depend on the availability of both APC-derived IL-12 and autocrine IFN-gamma consequent to the overall strength of T cell stimulation.", "title": "A direct role for IFN-gamma in regulation of Th1 cell development." }, { "docid": "3952288", "text": "Aire-expressing medullary thymic epithelial cells (mTECs) play a key role in preventing autoimmunity by expressing tissue-restricted antigens to help purge the emerging T cell receptor repertoire of self-reactive specificities. Here we demonstrate a novel role for a CD4+3− inducer cell population, previously linked to development of organized secondary lymphoid structures and maintenance of T cell memory in the functional regulation of Aire-mediated promiscuous gene expression in the thymus. CD4+3− cells are closely associated with mTECs in adult thymus, and in fetal thymus their appearance is temporally linked with the appearance of Aire+ mTECs. We show that RANKL signals from this cell promote the maturation of RANK-expressing CD80−Aire− mTEC progenitors into CD80+Aire+ mTECs, and that transplantation of RANK-deficient thymic stroma into immunodeficient hosts induces autoimmunity. Collectively, our data reveal cellular and molecular mechanisms leading to the generation of Aire+ mTECs and highlight a previously unrecognized role for CD4+3−RANKL+ inducer cells in intrathymic self-tolerance.", "title": "RANK signals from CD4+3− inducer cells regulate development of Aire-expressing epithelial cells in the thymic medulla" }, { "docid": "22997657", "text": "The transcription factor Kruppel-like factor 2 (KLF2) was proposed to regulate genes involved in cell cycle entry and T cell trafficking; however, the physiological role of its expression in postactivated T cells is not well defined. Previous studies suggested that the cytokines IL-2 and IL-15 differentially regulate KLF2 re-expression in postactivation T cells and that these cytokines also influence effector versus memory T cell differentiation. Using conditional and inducible KLF2-knockout model systems, we tested the specific role of KLF2 expression in activated CD8(+) T cells cultured with these cytokines. KLF2 was required for effective transcription of sphingosine-1-phosphate receptor-1 (S1P(1)) and CD62L in postactivation T cells. However, although different cytokines dramatically altered the expression of cell-cycle-related genes, endogenous KLF2 had a minimal impact. Correspondingly, KLF2-deficient T cells showed dysregulated trafficking but not altered proliferative characteristics following in vivo responses to Ag. Thus, our data help to define KLF2-dependent and -independent aspects of activated CD8(+) T cell differentiation and argue against a physiological role in cell cycle regulation.", "title": "Kruppel-like factor 2 is required for trafficking but not quiescence in postactivated T cells." }, { "docid": "10562341", "text": "The activation of T cells is the fundamental on switch for the adaptive immune system. Ca2+ signaling is essential for T cell activation and starts as initial, short-lived, localized Ca2+ signals. The second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) forms rapidly upon T cell activation and stimulates early Ca2+ signaling. We developed a high-resolution imaging technique using multiple fluorescent Ca2+ indicator dyes to characterize these early signaling events and investigate the channels involved in NAADP-dependent Ca2+ signals. In the first seconds of activation of either primary murine T cells or human Jurkat cells with beads coated with an antibody against CD3, we detected Ca2+ signals with diameters close to the limit of detection and that were close to the activation site at the plasma membrane. In Jurkat cells in which the ryanodine receptor (RyR) was knocked down or in primary T cells from RyR1−/− mice, either these early Ca2+ signals were not detected or the number of signals was markedly reduced. Local Ca2+ signals observed within 20 ms upon microinjection of Jurkat cells with NAADP were also sensitive to RyR knockdown. In contrast, TRPM2 (transient receptor potential channel, subtype melastatin 2), a potential NAADP target channel, was not required for the formation of initial Ca2+ signals in primary T cells. Thus, through our high-resolution imaging method, we characterized early Ca2+ release events in T cells and obtained evidence for the involvement of RyR and NAADP in such signals.", "title": "Frontrunners of T cell activation: Initial, localized Ca2+ signals mediated by NAADP and the type 1 ryanodine receptor" }, { "docid": "29015485", "text": "CD8(+) T cells can respond to unrelated infections in an Ag-independent manner. This rapid innate-like immune response allows Ag-experienced T cells to alert other immune cell types to pathogenic intruders. In this study, we show that murine CD8(+) T cells can sense TLR2 and TLR7 ligands, resulting in rapid production of IFN-γ but not of TNF-α and IL-2. Importantly, Ag-experienced T cells activated by TLR ligands produce sufficient IFN-γ to augment the activation of macrophages. In contrast to Ag-specific reactivation, TLR-dependent production of IFN-γ by CD8(+) T cells relies exclusively on newly synthesized transcripts without inducing mRNA stability. Furthermore, transcription of IFN-γ upon TLR triggering depends on the activation of PI3K and serine-threonine kinase Akt, and protein synthesis relies on the activation of the mechanistic target of rapamycin. We next investigated which energy source drives the TLR-induced production of IFN-γ. Although Ag-specific cytokine production requires a glycolytic switch for optimal cytokine release, glucose availability does not alter the rate of IFN-γ production upon TLR-mediated activation. Rather, mitochondrial respiration provides sufficient energy for TLR-induced IFN-γ production. To our knowledge, this is the first report describing that TLR-mediated bystander activation elicits a helper phenotype of CD8(+) T cells. It induces a short boost of IFN-γ production that leads to a significant but limited activation of Ag-experienced CD8(+) T cells. This activation suffices to prime macrophages but keeps T cell responses limited to unrelated infections.", "title": "TLR-Mediated Innate Production of IFN-γ by CD8+ T Cells Is Independent of Glycolysis." }, { "docid": "46926352", "text": "Immune cells continuously recirculate through lymph vessels en route from peripheral tissues to the blood. Leuyte trafficking into and within lymph vessels is mediated by an interply with lymphatic endothelial cells (LECs). However, lymphatic vessels are much more than mere conduits for fluid and immune cell transport. Data accumulating during past several years indicate that LECs support T cell survival, induce tolerance to self-antigens, inhibit exaggerated T cell proliferation during immune response and maintain T cell memory. Reciprocally, leukocytes impact LEC biology: lymphatic vessel permeability depends on DCs while lymphocytes regulate LEC proliferation during inflammation. Altogether, these novel results provide important insights on intimate connections between LECs and leukocytes that contribute to the understanding of immune responses.", "title": "Dendritic cells, T cells and lymphatics: dialogues in migration and beyond." }, { "docid": "3155731", "text": "T cells have crucial roles in protection against infection and cancer. Although the trafficking of memory T cells around the body is integral to their capacity to provide immune protection, studies have shown that specialization of some memory T cells into unique tissue-resident subsets gives the host enhanced regional immunity. In recent years, there has been considerable progress in our understanding of tissue-resident T cell development and function, revealing mechanisms for enhanced protective immunity that have the potential to influence rational vaccine design. This Review discusses the major advances and the emerging concepts in this field, summarizes what is known about the differentiation and the protective functions of tissue-resident memory T cells in different tissues in the body and highlights key unanswered questions.", "title": "Tissue-resident memory T cells: local specialists in immune defence" }, { "docid": "2474731", "text": "The cornea is an immune privileged tissue. Since arginase has been found to modulate T-cell function by depleting arginine, we investigated the expression of arginase in the cornea and its possible role in immune privilege using a murine transplant model. We found that both the endothelium and epithelium of murine corneas express functional arginase I, capable of down-regulating T-cell proliferation in an in vitro culture system. The administration of the specific arginase inhibitor N-hydroxy-nor-L-Arg to recipient mice resulted in an accelerated rejection of allogeneic C57BL/6 (B6) corneal grafts. In contrast, in vivo blockade of arginase activity had no effect in altering the course of rejection of primary skin grafts that express little, if any, arginase. In addition, the inhibition of arginase did not alter systemic T-cell proliferation. These data show that arginase is functional in the cornea and contributes to the immune privilege of the eye, and that modulation of arginase contributes to graft survival.", "title": "Arginine depletion as a mechanism for the immune privilege of corneal allografts" } ]

[ { "docid": "9558539", "text": "Cancer stem cells drive tumor formation and metastasis, but how they acquire metastatic traits is not well understood. Here, we show that all colorectal cancer stem cells (CR-CSCs) express CD44v6, which is required for their migration and generation of metastatic tumors. CD44v6 expression is low in primary tumors but demarcated clonogenic CR-CSC populations. Cytokines hepatocyte growth factor (HGF), osteopontin (OPN), and stromal-derived factor 1α (SDF-1), secreted from tumor associated cells, increase CD44v6 expression in CR-CSCs by activating the Wnt/β-catenin pathway, which promotes migration and metastasis. CD44v6(-) progenitor cells do not give rise to metastatic lesions but, when treated with cytokines, acquire CD44v6 expression and metastatic capacity. Importantly, phosphatidylinositol 3-kinase (PI3K) inhibition selectively killed CD44v6 CR-CSCs and reduced metastatic growth. In patient cohorts, low levels of CD44v6 predict increased probability of survival. Thus, the metastatic process in colorectal cancer is initiated by CSCs through the expression of CD44v6, which is both a functional biomarker and therapeutic target.", "title": "CD44v6 is a marker of constitutive and reprogrammed cancer stem cells driving colon cancer metastasis." } ]

[ { "docid": "25513319", "text": "Metabolic pathway reprogramming is a hallmark of cancer cell growth and survival and supports the anabolic and energetic demands of these rapidly dividing cells. The underlying regulators of the tumor metabolic program are not completely understood; however, these factors have potential as cancer therapy targets. Here, we determined that upregulation of the oncogenic transcriptional coregulator steroid receptor coactivator 2 (SRC-2), also known as NCOA2, drives glutamine-dependent de novo lipogenesis, which supports tumor cell survival and eventual metastasis. SRC-2 was highly elevated in a variety of tumors, especially in prostate cancer, in which SRC-2 was amplified and overexpressed in 37% of the metastatic tumors evaluated. In prostate cancer cells, SRC-2 stimulated reductive carboxylation of α-ketoglutarate to generate citrate via retrograde TCA cycling, promoting lipogenesis and reprogramming of glutamine metabolism. Glutamine-mediated nutrient signaling activated SRC-2 via mTORC1-dependent phosphorylation, which then triggered downstream transcriptional responses by coactivating SREBP-1, which subsequently enhanced lipogenic enzyme expression. Metabolic profiling of human prostate tumors identified a massive increase in the SRC-2-driven metabolic signature in metastatic tumors compared with that seen in localized tumors, further implicating SRC-2 as a prominent metabolic coordinator of cancer metastasis. Moreover, SRC-2 inhibition in murine models severely attenuated the survival, growth, and metastasis of prostate cancer. Together, these results suggest that the SRC-2 pathway has potential as a therapeutic target for prostate cancer.", "title": "Coactivator SRC-2-dependent metabolic reprogramming mediates prostate cancer survival and metastasis." }, { "docid": "41548287", "text": "Pancreatic ductal adenocarcinoma (PDAC) and other carcinomas are hierarchically organized, with cancer stem cells (CSC) residing at the top of the hierarchy, where they drive tumor progression, metastasis, and chemoresistance. As CSC and non-CSC share an identical genetic background, we hypothesize that differences in epigenetics account for the striking functional differences between these two cell populations. Epigenetic mechanisms, such as DNA methylation, play an important role in maintaining pluripotency and regulating the differentiation of stem cells, but the role of DNA methylation in pancreatic CSC is obscure. In this study, we investigated the genome-wide DNA methylation profile of PDAC CSC, and we determined the importance of DNA methyltransferases for CSC maintenance and tumorigenicity. Using high-throughput methylation analysis, we discovered that sorted CSCs have a higher level of DNA methylation, regardless of the heterogeneity or polyclonality of the CSC populations present in the tumors analyzed. Mechanistically, CSC expressed higher DNMT1 levels than non-CSC. Pharmacologic or genetic targeting of DNMT1 in CSCs reduced their self-renewal and in vivo tumorigenic potential, defining DNMT1 as a candidate CSC therapeutic target. The inhibitory effect we observed was mediated in part through epigenetic reactivation of previously silenced miRNAs, in particular the miR-17-92 cluster. Together, our findings indicate that DNA methylation plays an important role in CSC biology and also provide a rationale to develop epigenetic modulators to target CSC plasticity and improve the poor outcome of PDAC patients. Cancer Res; 76(15); 4546-58. ©2016 AACR.", "title": "DNMT1 Inhibition Reprograms Pancreatic Cancer Stem Cells via Upregulation of the miR-17-92 Cluster." }, { "docid": "13011249", "text": "The hallmarks of cancer comprise six biological capabilities acquired during the multistep development of human tumors. The hallmarks constitute an organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. Underlying these hallmarks are genome instability, which generates the genetic diversity that expedites their acquisition, and inflammation, which fosters multiple hallmark functions. Conceptual progress in the last decade has added two emerging hallmarks of potential generality to this list-reprogramming of energy metabolism and evading immune destruction. In addition to cancer cells, tumors exhibit another dimension of complexity: they contain a repertoire of recruited, ostensibly normal cells that contribute to the acquisition of hallmark traits by creating the \"tumor microenvironment. \" Recognition of the widespread applicability of these concepts will increasingly affect the development of new means to treat human cancer.", "title": "Hallmarks of Cancer: The Next Generation" }, { "docid": "24349992", "text": "Loss of stromal fibroblast caveolin-1 (Cav-1) is a powerful single independent predictor of poor prognosis in human breast cancer patients, and is associated with early tumor recurrence, lymph node metastasis and tamoxifen-resistance. We developed a novel co-culture system to understand the mechanism(s) by which a loss of stromal fibroblast Cav-1 induces a \"lethal tumor micro-environment. \" Here, we propose a new paradigm to explain the powerful prognostic value of stromal Cav-1. In this model, cancer cells induce oxidative stress in cancer-associated fibroblasts, which then acts as a \"metabolic\" and \"mutagenic\" motor to drive tumor-stroma co-evolution, DNA damage and aneuploidy in cancer cells. More specifically, we show that an acute loss of Cav-1 expression leads to mitochondrial dysfunction, oxidative stress and aerobic glycolysis in cancer associated fibroblasts. Also, we propose that defective mitochondria are removed from cancer-associated fibroblasts by autophagy/mitophagy that is induced by oxidative stress. As a consequence, cancer associated fibroblasts provide nutrients (such as lactate) to stimulate mitochondrial biogenesis and oxidative metabolism in adjacent cancer cells (the \"Reverse Warburg Effect\"). We provide evidence that oxidative stress in cancer-associated fibroblasts is sufficient to induce genomic instability in adjacent cancer cells, via a bystander effect, potentially increasing their aggressive behavior. Finally, we directly demonstrate that nitric oxide (NO) over-production, secondary to Cav-1 loss, is the root cause for mitochondrial dysfunction in cancer associated fibroblasts. In support of this notion, treatment with anti-oxidants (such as N-acetyl-cysteine, metformin and quercetin) or NO inhibitors (L-NAME) was sufficient to reverse many of the cancer-associated fibroblast phenotypes that we describe. Thus, cancer cells use \"oxidative stress\" in adjacent fibroblasts (i) as an \"engine\" to fuel their own survival via the stromal production of nutrients and (ii) to drive their own mutagenic evolution towards a more aggressive phenotype, by promoting genomic instability. We also present evidence that the \"field effect\" in cancer biology could also be related to the stromal production of ROS and NO species. eNOS-expressing fibroblasts have the ability to downregulate Cav-1 and induce mitochondrial dysfunction in adjacent fibroblasts that do not express eNOS. As such, the effects of stromal oxidative stress can be laterally propagated, amplified and are effectively \"contagious\"--spread from cell-to-cell like a virus--creating an \"oncogenic/mutagenic\" field promoting widespread DNA damage.", "title": "Oxidative stress in cancer associated fibroblasts drives tumor-stroma co-evolution: A new paradigm for understanding tumor metabolism, the field effect and genomic instability in cancer cells." }, { "docid": "15946643", "text": "Metastasis and chemoresistance in cancer are linked phenomena, but the molecular basis for this link is unknown. We uncovered a network of paracrine signals between carcinoma, myeloid, and endothelial cells that drives both processes in breast cancer. Cancer cells that overexpress CXCL1 and 2 by transcriptional hyperactivation or 4q21 amplification are primed for survival in metastatic sites. CXCL1/2 attract CD11b(+)Gr1(+) myeloid cells into the tumor, which produce chemokines including S100A8/9 that enhance cancer cell survival. Although chemotherapeutic agents kill cancer cells, these treatments trigger a parallel stromal reaction leading to TNF-α production by endothelial and other stromal cells. TNF-α via NF-kB heightens the CXCL1/2 expression in cancer cells, thus amplifying the CXCL1/2-S100A8/9 loop and causing chemoresistance. CXCR2 blockers break this cycle, augmenting the efficacy of chemotherapy against breast tumors and particularly against metastasis. This network of endothelial-carcinoma-myeloid signaling interactions provides a mechanism linking chemoresistance and metastasis, with opportunities for intervention.", "title": "A CXCL1 Paracrine Network Links Cancer Chemoresistance and Metastasis" }, { "docid": "7583725", "text": "TRPM7 encodes a Ca2+-permeable nonselective cation channel with kinase activity. TRPM7 has been implicated in control of cell adhesion and migration, but whether TRPM7 activity contributes to cancer progression has not been established. Here we report that high levels of TRPM7 expression independently predict poor outcome in breast cancer patients and that it is functionally required for metastasis formation in a mouse xenograft model of human breast cancer. Mechanistic investigation revealed that TRPM7 regulated myosin II-based cellular tension, thereby modifying focal adhesion number, cell-cell adhesion and polarized cell movement. Our findings therefore suggest that TRPM7 is part of a mechanosensory complex adopted by cancer cells to drive metastasis formation.", "title": "TRPM7 is required for breast tumor cell metastasis." }, { "docid": "3727986", "text": "Cancer-associated fibroblasts (CAFs) promote tumour invasion and metastasis. We show that CAFs exert a physical force on cancer cells that enables their collective invasion. Force transmission is mediated by a heterophilic adhesion involving N-cadherin at the CAF membrane and E-cadherin at the cancer cell membrane. This adhesion is mechanically active; when subjected to force it triggers β-catenin recruitment and adhesion reinforcement dependent on α-catenin/vinculin interaction. Impairment of E-cadherin/N-cadherin adhesion abrogates the ability of CAFs to guide collective cell migration and blocks cancer cell invasion. N-cadherin also mediates repolarization of the CAFs away from the cancer cells. In parallel, nectins and afadin are recruited to the cancer cell/CAF interface and CAF repolarization is afadin dependent. Heterotypic junctions between CAFs and cancer cells are observed in patient-derived material. Together, our findings show that a mechanically active heterophilic adhesion between CAFs and cancer cells enables cooperative tumour invasion.", "title": "A mechanically active heterotypic E-cadherin/N-cadherin adhesion enables fibroblasts to drive cancer cell invasion" }, { "docid": "9600826", "text": "Angiogenesis and cancer invasiveness greatly contribute to cancer malignancy. Arf6 and its effector, AMAP1, are frequently overexpressed in breast cancer, and constitute a central pathway to induce the invasion and metastasis. In this pathway, Arf6 is activated by EGFR via GEP100. Arf6 is highly expressed also in human umbilical vein endothelial cells (HUVECs) and is implicated in angiogenesis. Here, we found that HUVECs also highly express AMAP1, and that vascular endothelial growth factor receptor-2 (VEGFR2) recruits GEP100 to activate Arf6. AMAP1 functions by binding to cortactin in cancer invasion and metastasis. We demonstrate that the same GEP100-Arf6-AMAP1-cortactin pathway is essential for angiogenesis activities, including cell migration and tubular formation, as well as for the enhancement of cell permeability and VE-cadherin endocytosis of VEGF-stimulated HUVECs. Components of this pathway are highly expressed in pathologic angiogenesis, and blocking of this pathway effectively inhibits VEGF- or tumor-induced angiogenesis and choroidal neovascularization. The GEP100-Arf6-AMAP1-cortactin pathway, activated by receptor tyrosine kinases, appears to be common in angiogenesis and cancer invasion and metastasis, and provides their new therapeutic targets.", "title": "GEP100-Arf6-AMAP1-Cortactin Pathway Frequently Used in Cancer Invasion Is Activated by VEGFR2 to Promote Angiogenesis" }, { "docid": "21676556", "text": "The midbody is a singular organelle formed between daughter cells during cytokinesis and required for their final separation. Midbodies persist in cells long after division as midbody derivatives (MBds), but their fate is unclear. Here we show that MBds are inherited asymmetrically by the daughter cell with the older centrosome. They selectively accumulate in stem cells, induced pluripotent stem cells and potential cancer ‘stem cells’ in vivo and in vitro. MBd loss accompanies stem-cell differentiation, and involves autophagic degradation mediated by binding of the autophagic receptor NBR1 to the midbody protein CEP55. Differentiating cells and normal dividing cells do not accumulate MBds and possess high autophagic activity. Stem cells and cancer cells accumulate MBds by evading autophagosome encapsulation and exhibit low autophagic activity. MBd enrichment enhances reprogramming to induced pluripotent stem cells and increases the in vitro tumorigenicity of cancer cells. These results indicate unexpected roles for MBds in stem cells and cancer ‘stem cells’.", "title": "Midbody accumulation through evasion of autophagy contributes to cellular reprogramming and tumorigenicity" }, { "docid": "17021845", "text": "The aim of the present study was to analyze the stem cell marker, Nanog gene, for the diagnosis and prognosis of lung cancer cases, and to study its application in the diagnosis of lung cancer. In total, 100 patients diagnosed with lung cancer between April, 2013 and May, 2015 were included in the present study. The patients were randomly divided into group A (lung cancer) and group B (squamous cell lung carcinoma). RT-PCR was used to detect the cancer and adjacent tissues, and Nanog gene expression was detected in groups A and B in cells. The results showed that, analysis of Nanog gene expression in the two groups of patients varied to different degrees. There was no significant difference between the two groups with regard to age, gender, disease stage and lymph node metastasis. Nanog gene expression in patients with carcinoma were significantly higher than that in the adjacent tissues (p<0.05). By contrast, differentiated and well-differentiated carcinoma tissue showed a significantly higher Nanog gene expression than poorly differentiated and undifferentiated carcinoma (p<0.05). The expression of Nanog in normal cells was significantly higher than that in normal lung tissues and benign lesions in lung cancer stem cells. Nanog was highly expressed in CD44+ cells, and Nanog expression in lung cancer stem cells was significantly higher (p<0.05). In conclusion, for groups A (lung cancer) and B (squamous cell lung carcinoma) the Nanog gene expression was significantly higher. The data of the present study show that the patients with stage III and IV lung cancer had a higher Nanog gene expression. In addition, there was a higher expression of Nanog in lung cancer patients. By contrast, a lower degree of cell differentiation was associated with strong Nanog gene expression in lung cancer.", "title": "Significance of stem cell marker Nanog gene in the diagnosis and prognosis of lung cancer" }, { "docid": "8702697", "text": "AIMS Tumor microenvironment is a strong determinant for the acquisition of metastatic potential of cancer cells. We have recently demonstrated that cancer-associated fibroblasts (CAFs) elicit a redox-dependent epithelial-mesenchymal transition (EMT) in prostate cancer (PCa) cells, driven by cycloxygenase-2/hypoxia-inducible factor-1 (HIF-1)/nuclear factor-κB pathway and enhancing tumor aggressiveness. Here, we investigated the involvement of microRNAs (miRNAs) in tumor-stroma interplay to identify possible tools to counteract oxidative stress and metastasis dissemination. \n RESULTS We found that miR-205 is the most downmodulated miRNA in PCa cells upon CAF stimulation, due to direct transcriptional repression by HIF-1, a known redox-sensitive transcription factor. Rescue experiments demonstrated that ectopic miR-205 overexpression in PCa cells counteracts CAF-induced EMT, thus impairing enhancement of cell invasion, acquisition of stem cell traits, tumorigenicity, and metastatic dissemination. In addition, miR-205 blocks tumor-driven activation of surrounding fibroblasts by reducing pro-inflammatory cytokine secretion. INNOVATION Overall, such findings suggest miR-205 as a brake against PCa metastasis by blocking both the afferent and efferent arms of the circuit between tumor cells and associated fibroblasts, thus interrupting the pro-oxidant and pro-inflammatory circuitries engaged by reactive stroma. \n CONCLUSION The evidence that miR-205 replacement in PCa cells is able not only to prevent but also to revert the oxidative/pro-inflammatory axis leading to EMT induced by CAFs sets the rationale for developing miRNA-based approaches to prevent and treat metastatic disease.", "title": "miR-205 hinders the malignant interplay between prostate cancer cells and associated fibroblasts." }, { "docid": "16532419", "text": "BACKGROUND Carbon nanotubes (CNT) hold great promise to create new and better products for commercial and biomedical applications, but their long-term adverse health effects are a major concern. The objective of this study was to address human lung cancer risks associated with chronic pulmonary exposure to single-walled (SW) CNT through the fundamental understanding of cellular and molecular processes leading to carcinogenesis. We hypothesized that the acquisition of cancer stem cells (CSC), a subpopulation that drive tumor initiation and progression, may contribute to CNT carcinogenesis. \n METHODS Non-tumorigenic human lung epithelial cells were chronically exposed to well-dispersed SWCNT for a period of 6 months at the physiologically relevant concentration of 0.02 μg/cm2 surface area dose. Chronic SWCNT-exposed cells were evaluated for the presence of CSC-like cells under CSC-selective conditions of tumor spheres and side population (SP). CSC-like cells were isolated using fluorescence-activated cell sorting and were assessed for aggressive behaviors, including acquired apoptosis resistance and increased cell migration and invasion in vitro, and tumor-initiating capability in vivo. Non-small cell lung cancer cells served as a positive control. \n RESULTS We demonstrated for the first time the existence of CSC-like cells in all clones of chronic SWCNT-exposed lung epithelial cells. These CSC-like cells, in contrary to their non-CSC counterpart, possessed all biological features of lung CSC that are central to irreversible malignant transformation, self-renewal, aggressive cancer behaviors, and in vivo tumorigenesis. These cells also displayed aberrant stem cell markers, notably Nanog, SOX-2, SOX-17 and E-cadherin. Restored expression of tumor suppressor p53 abrogated CSC properties of CSC-like cells. Furthermore, we identified specific stem cell surface markers CD24low and CD133high that are associated with SWCNT-induced CSC formation and tumorigenesis. \n CONCLUSIONS Our findings provide new and compelling evidence for the acquisition of CSC-like cells induced by chronic SWCNT exposure, which are likely to be a major driving force for SWCNT tumorigenesis. Thus, our study supports prudent adoption of prevention strategies and implementation of exposure control for SWCNT. We also suggest that the detection of CSC and associated surface markers may provide an effective screening tool for prediction of the carcinogenic potential of SWCNT and related nanoparticles.", "title": "Induction of stem-like cells with malignant properties by chronic exposure of human lung epithelial cells to single-walled carbon nanotubes" }, { "docid": "2608447", "text": "Defined transcription factors can induce epigenetic reprogramming of adult mammalian cells into induced pluripotent stem cells. Although DNA factors are integrated during some reprogramming methods, it is unknown whether the genome remains unchanged at the single nucleotide level. Here we show that 22 human induced pluripotent stem (hiPS) cell lines reprogrammed using five different methods each contained an average of five protein-coding point mutations in the regions sampled (an estimated six protein-coding point mutations per exome). The majority of these mutations were non-synonymous, nonsense or splice variants, and were enriched in genes mutated or having causative effects in cancers. At least half of these reprogramming-associated mutations pre-existed in fibroblast progenitors at low frequencies, whereas the rest occurred during or after reprogramming. Thus, hiPS cells acquire genetic modifications in addition to epigenetic modifications. Extensive genetic screening should become a standard procedure to ensure hiPS cell safety before clinical use.", "title": "Somatic coding mutations in human induced pluripotent stem cells" }, { "docid": "42106119", "text": "The transcription factor Oct4 is key in embryonic stem cell identity and reprogramming. Insight into its partners should illuminate how the pluripotent state is established and regulated. Here, we identify a considerably expanded set of Oct4-binding proteins in mouse embryonic stem cells. We find that Oct4 associates with a varied set of proteins including regulators of gene expression and modulators of Oct4 function. Half of its partners are transcriptionally regulated by Oct4 itself or other stem cell transcription factors, whereas one-third display a significant change in expression upon cell differentiation. The majority of Oct4-associated proteins studied to date show an early lethal phenotype when mutated. A fraction of the human orthologs is associated with inherited developmental disorders or causative of cancer. The Oct4 interactome provides a resource for dissecting mechanisms of Oct4 function, enlightening the basis of pluripotency and development, and identifying potential additional reprogramming factors.", "title": "An Expanded Oct4 Interaction Network: Implications for Stem Cell Biology, Development, and Disease" }, { "docid": "22712546", "text": "Over the past years, plenty of evidence has emerged illustrating how metabolism supports many aspects of cellular function and how metabolic reprogramming can drive cell differentiation and fate. Here, we present a method to assess the metabolic configuration of single cells within their native tissue microenvironment via the visualization and quantification of multiple enzymatic activities measured at saturating substrate conditions combined with subsequent cell type identification. After careful validation of the approach and to demonstrate its potential, we assessed the intracellular metabolic configuration of different human immune cell populations in healthy and tumor colon tissue. Additionally, we analyzed the intercellular metabolic relationship between cancer cells and cancer-associated fibroblasts in a breast cancer tissue array. This study demonstrates that the determination of metabolic configurations in single cells could be a powerful complementary tool for every researcher interested to study metabolic networks in situ.", "title": "Exploring Metabolic Configurations of Single Cells within Complex Tissue Microenvironments." }, { "docid": "12100854", "text": "Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) involves a marked reorganization of chromatin. To identify post-translational histone modifications that change in global abundance during this process, we have applied a quantitative mass-spectrometry-based approach. We found that iPSCs, compared with both the starting fibroblasts and a late reprogramming intermediate (pre-iPSCs), are enriched for histone modifications associated with active chromatin, and depleted for marks of transcriptional elongation and a subset of repressive modifications including H3K9me2/me3. Dissecting the contribution of H3K9 methylation to reprogramming, we show that the H3K9 methyltransferases Ehmt1, Ehmt2 and Setdb1 regulate global H3K9me2/me3 levels and that their depletion increases iPSC formation from both fibroblasts and pre-iPSCs. Similarly, we find that inhibition of heterochromatin protein-1γ (Cbx3), a protein known to recognize H3K9 methylation, enhances reprogramming. Genome-wide location analysis revealed that Cbx3 predominantly binds active genes in both pre-iPSCs and pluripotent cells but with a strikingly different distribution: in pre-iPSCs, but not in embryonic stem cells, Cbx3 associates with active transcriptional start sites, suggesting a developmentally regulated role for Cbx3 in transcriptional activation. Despite largely non-overlapping functions and the predominant association of Cbx3 with active transcription, the H3K9 methyltransferases and Cbx3 both inhibit reprogramming by repressing the pluripotency factor Nanog. Together, our findings demonstrate that Cbx3 and H3K9 methylation restrict late reprogramming events, and suggest that a marked change in global chromatin character constitutes an epigenetic roadblock for reprogramming.", "title": "Proteomic and genomic approaches reveal critical functions of H3K9 methylation and Heterochromatin Protein-1γ in reprogramming to pluripotency" }, { "docid": "32742683", "text": "Among cells present in the tumor microenvironment, activated fibroblasts termed cancer-associated fibroblasts (CAFs), play a critical role in the complex process of tumor-stroma interaction. CAFs, one of the prominent stromal cell populations in most types of human carcinomas, have been involved in tumor growth, angiogenesis, cancer stemness, extracellular matrix remodeling, tissue invasion, metastasis, and even chemoresistance. During the past decade, these activated tumor-associated fibroblasts have also been involved in the modulation of the anti-tumor immune response on various levels. In this review, we describe our current understanding of how CAFs accomplish this task as well as their potential therapeutic implications.", "title": "Alteration of the Antitumor Immune Response by Cancer-Associated Fibroblasts" }, { "docid": "6441369", "text": "The interconversion between naive and primed pluripotent states is accompanied by drastic epigenetic rearrangements. However, it is unclear whether intrinsic epigenetic events can drive reprogramming to naive pluripotency or if distinct chromatin states are instead simply a reflection of discrete pluripotent states. Here, we show that blocking histone H3K4 methyltransferase MLL1 activity with the small-molecule inhibitor MM-401 reprograms mouse epiblast stem cells (EpiSCs) to naive pluripotency. This reversion is highly efficient and synchronized, with more than 50% of treated EpiSCs exhibiting features of naive embryonic stem cells (ESCs) within 3 days. Reverted ESCs reactivate the silenced X chromosome and contribute to embryos following blastocyst injection, generating germline-competent chimeras. Importantly, blocking MLL1 leads to global redistribution of H3K4me1 at enhancers and represses lineage determinant factors and EpiSC markers, which indirectly regulate ESC transcription circuitry. These findings show that discrete perturbation of H3K4 methylation is sufficient to drive reprogramming to naive pluripotency.", "title": "MLL1 Inhibition Reprograms Epiblast Stem Cells to Naive Pluripotency." }, { "docid": "825728", "text": "The epithelial-mesenchymal transition (EMT) is required in the embryo for the formation of tissues for which cells originate far from their final destination. Carcinoma cells hijack this program for tumor dissemination. The relevance of the EMT in cancer is still debated because it is unclear how these migratory cells colonize distant tissues to form macrometastases. We show that the homeobox factor Prrx1 is an EMT inducer conferring migratory and invasive properties. The loss of Prrx1 is required for cancer cells to metastasize in vivo, which revert to the epithelial phenotype concomitant with the acquisition of stem cell properties. Thus, unlike the classical EMT transcription factors, Prrx1 uncouples EMT and stemness, and is a biomarker associated with patient survival and lack of metastasis.", "title": "Metastatic colonization requires the repression of the epithelial-mesenchymal transition inducer Prrx1." } ]

[ { "docid": "7898952", "text": "We have developed a nonheuristic genome topography scan (GTS) algorithm to characterize the patterns of genomic alterations in human glioblastoma (GBM), identifying frequent p18(INK4C) and p16(INK4A) codeletion. Functional reconstitution of p18(INK4C) in GBM cells null for both p16(INK4A) and p18(INK4C) resulted in impaired cell-cycle progression and tumorigenic potential. Conversely, RNAi-mediated depletion of p18(INK4C) in p16(INK4A)-deficient primary astrocytes or established GBM cells enhanced tumorigenicity in vitro and in vivo. Furthermore, acute suppression of p16(INK4A) in primary astrocytes induced a concomitant increase in p18(INK4C). Together, these findings uncover a feedback regulatory circuit in the astrocytic lineage and demonstrate a bona fide tumor suppressor role for p18(INK4C) in human GBM wherein it functions cooperatively with other INK4 family members to constrain inappropriate proliferation.", "title": "Feedback Circuit among INK4 Tumor Suppressors Constrains Human Glioblastoma Development" } ]

[ { "docid": "470625", "text": "Genomic alterations leading to aberrant activation of cyclin/cyclin-dependent kinase (cdk) complexes drive the pathogenesis of many common human tumor types. In the case of glioblastoma multiforme (GBM), these alterations are most commonly due to homozygous deletion of p16(INK4a) and less commonly due to genomic amplifications of individual genes encoding cyclins or cdks. Here, we describe deletion of the p18(INK4c) cdk inhibitor as a novel genetic alteration driving the pathogenesis of GBM. Deletions of p18(INK4c) often occurred in tumors also harboring homozygous deletions of p16(INK4a). Expression of p18(INK4c) was completely absent in 43% of GBM primary tumors studied by immunohistochemistry. Lentiviral reconstitution of p18(INK4c) expression at physiologic levels in p18(INK4c)-deficient but not p18(INK4c)-proficient GBM cells led to senescence-like G(1) cell cycle arrest. These studies identify p18(INK4c) as a GBM tumor suppressor gene, revealing an additional mechanism leading to aberrant activation of cyclin/cdk complexes in this terrible malignancy.", "title": "Identification of p18 INK4c as a tumor suppressor gene in glioblastoma multiforme." }, { "docid": "7717468", "text": "Microbial survival in a host is usually dependent on the ability of a pathogen to undergo changes that promote escape from host defense mechanisms. The human-pathogenic fungus Cryptococcus neoformans undergoes phenotypic switching in vivo that promotes persistence in tissue. By microarray and real-time PCR analyses, the allergen 1 gene (ALL1) was found to be downregulated in the hypervirulent mucoid switch variant, both during logarithmic growth and during intracellular growth in macrophages. The ALL1 gene encodes a small cytoplasmic protein that is involved in capsule formation. Growth of an all1Delta gene deletion mutant was normal. Similar to cells of the mucoid switch variant, all1Delta cells produced a larger polysaccharide capsule than cells of the smooth parent and the complemented strain produced, and the enlarged capsule inhibited macrophage phagocytosis. The mutant exhibited a modest defect in capsule induction compared to all of the other variants. In animal models the phenotype of the all1Delta mutant mimicked the hypervirulent phenotype of the mucoid switch variant, which is characterized by decreased host survival and elevated intracranial pressure. Decreased survival is likely the result of both an ineffective cell-mediated immune response and impaired phagocytosis by macrophages. Consequently, we concluded that, unlike loss of most virulence-associated genes, where loss of gene function results in attenuated virulence, loss of the ALL1 gene enhances virulence by altering the host-pathogen interaction and thereby impairing clearance. Our data identified the first cryptococcal gene associated with elevated intracranial pressure and support the hypothesis that an environmental opportunistic pathogen has modified its virulence in vivo by epigenetic downregulation of gene function.", "title": "Loss of allergen 1 confers a hypervirulent phenotype that resembles mucoid switch variants of Cryptococcus neoformans." }, { "docid": "344240", "text": "Actions of protein products resulting from alternative splicing of the Igf1 gene have received increasing attention in recent years. However, the significance and functional relevance of these observations remain poorly defined. To address functions of IGF-I splice variants, we examined the impact of loss of IGF-IEa and IGF-IEb on the proliferation and differentiation of cultured mouse myoblasts. RNA interference-mediated reductions in total IGF-I, IGF-IEa alone, or IGF-IEb alone had no effect on cell viability in growth medium. However, cells deficient in total IGF-I or IGF-IEa alone proliferated significantly slower than control cells or cells deficient in IGF-IEb in serum-free media. Simultaneous loss of both or specific loss of either splice variant significantly inhibited myosin heavy chain (MyHC) immunoreactivity by 70-80% (P < 0.01) under differentiation conditions (48 h in 2% horse serum) as determined by Western immunoblotting. This loss in protein was associated with reduced MyHC isoform mRNAs, because reductions in total IGF-I or IGF-IEa mRNA significantly reduced MyHC mRNAs by approximately 50-75% (P < 0.05). Loss of IGF-IEb also reduced MyHC isoform mRNA significantly, with the exception of Myh7, but to a lesser degree (∼20-40%, P < 0.05). Provision of mature IGF-I, but not synthetic E peptides, restored Myh3 expression to control levels in cells deficient in IGF-IEa or IGF-IEb. Collectively, these data suggest that IGF-I splice variants may regulate myoblast differentiation through the actions of mature IGF-I and not the E peptides.", "title": "Loss of IGF-IEa or IGF-IEb impairs myogenic differentiation." }, { "docid": "3127341", "text": "The glucagon-like peptide-1 receptor (GLP-1R) is a key physiological regulator of insulin secretion and a major therapeutic target for the treatment of type II diabetes. However, regulation of GLP-1R function is complex with multiple endogenous peptides that interact with the receptor, including full-length (1-37) and truncated (7-37) forms of GLP-1 that can exist in an amidated form (GLP-1(1-36)NH₂ and GLP-1(7-36)NH₂) and the related peptide oxyntomodulin. In addition, the GLP-1R possesses exogenous agonists, including exendin-4, and the allosteric modulator, compound 2 (6,7-dichloro-2-methylsulfonyl-3-tert-butylaminoquinoxaline). The complexity of this ligand-receptor system is further increased by the presence of several single nucleotide polymorphisms (SNPs) that are distributed across the receptor. We have investigated 10 GLP-1R SNPs, which were characterized in three physiologically relevant signaling pathways (cAMP accumulation, extracellular signal-regulated kinase 1/2 phosphorylation, and intracellular Ca²⁺ mobilization); ligand binding and cell surface receptor expression were also determined. We demonstrate both ligand- and pathway-specific effects for multiple SNPs, with the most dramatic effect observed for the Met¹⁴⁹ receptor variant. At the Met¹⁴⁹ variant, there was selective loss of peptide-induced responses across all pathways examined, but preservation of response to the small molecule compound 2. In contrast, at the Cys³³³ variant, peptide responses were preserved but there was attenuated response to compound 2. Strikingly, the loss of peptide function at the Met¹⁴⁹ receptor variant could be allosterically rescued by compound 2, providing proof-of-principle evidence that allosteric drugs could be used to treat patients with this loss of function variant.", "title": "Polymorphism and ligand dependent changes in human glucagon-like peptide-1 receptor (GLP-1R) function: allosteric rescue of loss of function mutation." }, { "docid": "4407385", "text": "Memory function often declines with age, and is believed to deteriorate initially because of changes in synaptic function rather than loss of neurons. Some individuals then go on to develop Alzheimer's disease with neurodegeneration. Here we use Tg2576 mice, which express a human amyloid-β precursor protein (APP) variant linked to Alzheimer's disease, to investigate the cause of memory decline in the absence of neurodegeneration or amyloid-β protein amyloidosis. Young Tg2576 mice (< 6 months old) have normal memory and lack neuropathology, middle-aged mice (6–14 months old) develop memory deficits without neuronal loss, and old mice (> 14 months old) form abundant neuritic plaques containing amyloid-β (refs 3–6). We found that memory deficits in middle-aged Tg2576 mice are caused by the extracellular accumulation of a 56-kDa soluble amyloid-β assembly, which we term Aβ*56 (Aβ star 56). Aβ*56 purified from the brains of impaired Tg2576 mice disrupts memory when administered to young rats. We propose that Aβ*56 impairs memory independently of plaques or neuronal loss, and may contribute to cognitive deficits associated with Alzheimer's disease.", "title": "A specific amyloid-β protein assembly in the brain impairs memory" }, { "docid": "24311787", "text": "Variant histone H2AZ-containing nucleosomes are involved in the regulation of gene expression. In Saccharomyces cerevisiae, chromatin deposition of histone H2AZ is mediated by the fourteen-subunit SWR1 complex, which catalyzes ATP-dependent exchange of nucleosomal histone H2A for H2AZ. Previous work defined the role of seven SWR1 subunits (Swr1 ATPase, Swc2, Swc3, Arp6, Swc5, Yaf9, and Swc6) in maintaining complex integrity and H2AZ histone replacement activity. Here we examined the function of three additional SWR1 subunits, bromodomain containing Bdf1, actin-related protein Arp4 and Swc7, by analyzing affinity-purified mutant SWR1 complexes. We observed that depletion of Arp4 (arp4-td) substantially impaired the association of Bdf1, Yaf9, and Swc4. In contrast, loss of either Bdf1 or Swc7 had minimal effects on overall complex integrity. Furthermore, the basic H2AZ histone replacement activity of SWR1 in vitro required Arp4, but not Bdf1 or Swc7. Thus, three out of fourteen SWR1 subunits, Bdf1, Swc7, and previously noted Swc3, appear to have roles auxiliary to the basic histone replacement activity. The N-terminal region of the Swr1 ATPase subunit is necessary and sufficient to direct association of Bdf1 and Swc7, as well as Arp4, Act1, Yaf9 and Swc4. This same region contains an additional H2AZ-H2B specific binding site, distinct from the previously identified Swc2 subunit. These findings suggest that one SWR1 enzyme might be capable of binding two H2AZ-H2B dimers, and provide further insight on the hierarchy and interdependency of molecular interactions within the SWR1 complex.", "title": "N terminus of Swr1 binds to histone H2AZ and provides a platform for subunit assembly in the chromatin remodeling complex." }, { "docid": "4412772", "text": "Unicellular organisms such as yeasts require a single cyclin-dependent kinase, Cdk1, to drive cell division. In contrast, mammalian cells are thought to require the sequential activation of at least four different cyclin-dependent kinases, Cdk2, Cdk3, Cdk4 and Cdk6, to drive cells through interphase, as well as Cdk1 to proceed through mitosis. This model has been challenged by recent genetic evidence that mice survive in the absence of individual interphase Cdks. Moreover, most mouse cell types proliferate in the absence of two or even three interphase Cdks. Similar results have been obtained on ablation of some of the activating subunits of Cdks, such as the D-type and E-type cyclins. Here we show that mouse embryos lacking all interphase Cdks (Cdk2, Cdk3, Cdk4 and Cdk6) undergo organogenesis and develop to midgestation. In these embryos, Cdk1 binds to all cyclins, resulting in the phosphorylation of the retinoblastoma protein pRb and the expression of genes that are regulated by E2F transcription factors. Mouse embryonic fibroblasts derived from these embryos proliferate in vitro, albeit with an extended cell cycle due to inefficient inactivation of Rb proteins. However, they become immortal on continuous passage. We also report that embryos fail to develop to the morula and blastocyst stages in the absence of Cdk1. These results indicate that Cdk1 is the only essential cell cycle Cdk. Moreover, they show that in the absence of interphase Cdks, Cdk1 can execute all the events that are required to drive cell division.", "title": "Cdk1 is sufficient to drive the mammalian cell cycle" }, { "docid": "25479072", "text": "Cytotoxic T cell (CTL) activation by antigen requires the specific detection of peptide–major histo-compatibility class I (pMHC) molecules on the target-cell surface by the T cell receptor (TCR). We examined the effect of mutations in the antigen-binding site of a Kb-restricted TCR on T cell activation, antigen binding and dissociation from antigen. These parameters were also examined for variants derived from a Kd-restricted peptide that was recognized by a CTL clone. Using these two independent systems, we show that T cell activation can be impaired by mutations that either decrease or increase the binding half-life of the TCR-pMHC interaction. Our data indicate that efficient T cell activation occurs within an optimal dwell-time range of TCR-pMHC interaction. This restricted dwell-time range is consistent with the exclusion of either extremely low or high affinity T cells from the expanded population during immune responses.", "title": "Efficient T cell activation requires an optimal dwell-time of interaction between the TCR and the pMHC complex" }, { "docid": "16626264", "text": "Histone variants help specialize chromatin regions; however, their impact on transcriptional regulation is largely unknown. Here, we determined the genome-wide localization and dynamics of Htz1, the yeast histone H2A variant. Htz1 localizes to hundreds of repressed/basal Pol II promoters and prefers TATA-less promoters. Specific Htz1 deposition requires the SWR1 complex, which largely colocalizes with Htz1. Htz1 occupancy correlates with particular histone modifications, and Htz1 deposition is partially reliant on Gcn5 (a histone acetyltransferase) and Bdf1, an SWR1 complex member that binds acetylated histones. Changes in growth conditions cause a striking redistribution of Htz1 from activated to repressed/basal promoters. Furthermore, Htz1 promotes full gene activation but does not generally impact repression. Importantly, Htz1 releases from purified chromatin in vitro under conditions where H2A and H3 remain associated. We suggest that Htz1-bearing nucleosomes are deposited at repressed/basal promoters but facilitate activation through their susceptibility to loss, thereby helping to expose promoter DNA.", "title": "Genome-Wide Dynamics of Htz1, a Histone H2A Variant that Poises Repressed/Basal Promoters for Activation through Histone Loss" }, { "docid": "4993011", "text": "ATRX (alpha thalassemia/mental retardation X-linked) complexes with DAXX to deposit histone variant H3.3 into repetitive heterochromatin. Recent genome sequencing studies in cancers have revealed mutations in ATRX and their association with ALT (alternative lengthening of telomeres) activation. Here we report depletion of ATRX in mouse ES cells leads to selective loss in ribosomal RNA gene (rDNA) copy number. Supporting this, ATRX-mutated human ALT-positive tumors also show a substantially lower rDNA copy than ALT-negative tumors. Further investigation shows that the rDNA copy loss and repeat instability are caused by a disruption in H3.3 deposition and thus a failure in heterochromatin formation at rDNA repeats in the absence of ATRX. We also find that ATRX-depleted cells are reduced in ribosomal RNA transcription output and show increased sensitivity to RNA polymerase I (Pol I) transcription inhibitor CX5461. In addition, human ALT-positive cancer cell lines are also more sensitive to CX5461 treatment. Our study provides insights into the contribution of ATRX loss of function to tumorigenesis through the loss of rDNA stability and suggests the therapeutic potential of targeting Pol I transcription in ALT cancers.", "title": "Ribosomal DNA copy loss and repeat instability in ATRX-mutated cancers" }, { "docid": "17518195", "text": "Histone variants within the H2A family show high divergences in their C-terminal regions. In this work, we have studied how these divergences and in particular, how a part of the H2A COOH-terminus, the docking domain, is implicated in both structural and functional properties of the nucleosome. Using biochemical methods in combination with Atomic Force Microscopy and Electron Cryo-Microscopy, we show that the H2A-docking domain is a key structural feature within the nucleosome. Deletion of this domain or replacement with the incomplete docking domain from the variant H2A.Bbd results in significant structural alterations in the nucleosome, including an increase in overall accessibility to nucleases, un-wrapping of ∼10 bp of DNA from each end of the nucleosome and associated changes in the entry/exit angle of DNA ends. These structural alterations are associated with a reduced ability of the chromatin remodeler RSC to both remodel and mobilize the nucleosomes. Linker histone H1 binding is also abrogated in nucleosomes containing the incomplete docking domain of H2A.Bbd. Our data illustrate the unique role of the H2A-docking domain in coordinating the structural-functional aspects of the nucleosome properties. Moreover, our data suggest that incorporation of a 'defective' docking domain may be a primary structural role of H2A.Bbd in chromatin.", "title": "The docking domain of histone H2A is required for H1 binding and RSC-mediated nucleosome remodeling" }, { "docid": "4414547", "text": "Improved sequencing technologies offer unprecedented opportunities for investigating the role of rare genetic variation in common disease. However, there are considerable challenges with respect to study design, data analysis and replication. Using pooled next-generation sequencing of 507 genes implicated in the repair of DNA in 1,150 samples, an analytical strategy focused on protein-truncating variants (PTVs) and a large-scale sequencing case–control replication experiment in 13,642 individuals, here we show that rare PTVs in the p53-inducible protein phosphatase PPM1D are associated with predisposition to breast cancer and ovarian cancer. PPM1D PTV mutations were present in 25 out of 7,781 cases versus 1 out of 5,861 controls (P = 1.12 × 10−5), including 18 mutations in 6,912 individuals with breast cancer (P = 2.42 × 10−4) and 12 mutations in 1,121 individuals with ovarian cancer (P = 3.10 × 10−9). Notably, all of the identified PPM1D PTVs were mosaic in lymphocyte DNA and clustered within a 370-base-pair region in the final exon of the gene, carboxy-terminal to the phosphatase catalytic domain. Functional studies demonstrate that the mutations result in enhanced suppression of p53 in response to ionizing radiation exposure, suggesting that the mutant alleles encode hyperactive PPM1D isoforms. Thus, although the mutations cause premature protein truncation, they do not result in the simple loss-of-function effect typically associated with this class of variant, but instead probably have a gain-of-function effect. Our results have implications for the detection and management of breast and ovarian cancer risk. More generally, these data provide new insights into the role of rare and of mosaic genetic variants in common conditions, and the use of sequencing in their identification.", "title": "Mosaic PPM1D mutations are associated with predisposition to breast and ovarian cancer" }, { "docid": "5273056", "text": "Eukaryotes have numerous checkpoint pathways to protect genome fidelity during normal cell division and in response to DNA damage. Through a screen for G2/M checkpoint regulators in zebrafish, we identified ticrr (for TopBP1-interacting, checkpoint, and replication regulator), a previously uncharacterized gene that is required to prevent mitotic entry after treatment with ionizing radiation. Ticrr deficiency is embryonic-lethal in the absence of exogenous DNA damage because it is essential for normal cell cycle progression. Specifically, the loss of ticrr impairs DNA replication and disrupts the S/M checkpoint, leading to premature mitotic entry and mitotic catastrophe. We show that the human TICRR ortholog associates with TopBP1, a known checkpoint protein and a core component of the DNA replication preinitiation complex (pre-IC), and that the TICRR-TopBP1 interaction is stable without chromatin and requires BRCT motifs essential for TopBP1's replication and checkpoint functions. Most importantly, we find that ticrr deficiency disrupts chromatin binding of pre-IC, but not prereplication complex, components. Taken together, our data show that TICRR acts in association with TopBP1 and plays an essential role in pre-IC formation. It remains to be determined whether Ticrr represents the vertebrate ortholog of the yeast pre-IC component Sld3, or a hitherto unknown metazoan replication and checkpoint regulator.", "title": "A vertebrate gene, ticrr, is an essential checkpoint and replication regulator." }, { "docid": "857189", "text": "The protein cytotoxic T lymphocyte antigen-4 (CTLA-4) is an essential negative regulator of immune responses, and its loss causes fatal autoimmunity in mice. We studied a large family in which five individuals presented with a complex, autosomal dominant immune dysregulation syndrome characterized by hypogammaglobulinemia, recurrent infections and multiple autoimmune clinical features. We identified a heterozygous nonsense mutation in exon 1 of CTLA4. Screening of 71 unrelated patients with comparable clinical phenotypes identified five additional families (nine individuals) with previously undescribed splice site and missense mutations in CTLA4. Clinical penetrance was incomplete (eight adults of a total of 19 genetically proven CTLA4 mutation carriers were considered unaffected). However, CTLA-4 protein expression was decreased in regulatory T cells (Treg cells) in both patients and carriers with CTLA4 mutations. Whereas Treg cells were generally present at elevated numbers in these individuals, their suppressive function, CTLA-4 ligand binding and transendocytosis of CD80 were impaired. Mutations in CTLA4 were also associated with decreased circulating B cell numbers. Taken together, mutations in CTLA4 resulting in CTLA-4 haploinsufficiency or impaired ligand binding result in disrupted T and B cell homeostasis and a complex immune dysregulation syndrome.", "title": "Autosomal dominant immune dysregulation syndrome in humans with CTLA4 mutations" }, { "docid": "26625002", "text": "The outer membrane channel TolC is a key component of multidrug efflux and type I secretion transporters in Escherichia coli. Mutational inactivation of TolC renders cells highly susceptible to antibiotics and leads to defects in secretion of protein toxins. Despite impairment of various transport functions, no growth defects were reported in cells lacking TolC. Unexpectedly, we found that the loss of TolC notably impairs cell division and growth in minimal glucose medium. The TolC-dependent phenotype was further exacerbated by the loss of ygiB and ygiC genes expressed in the same operon as tolC and their homologues yjfM and yjfC located elsewhere on the chromosome. Our results show that this growth deficiency is caused by depletion of the critical metabolite NAD(+) and high NADH/NAD(+) ratios. The increased amounts of PspA and decreased rates of NADH oxidation in Delta tolC membranes indicated stress on the membrane and dissipation of a proton motive force. We conclude that inactivation of TolC triggers metabolic shutdown in E. coli cells grown in minimal glucose medium. The Delta tolC phenotype is partially rescued by YgiBC and YjfMC, which have parallel functions independent from TolC.", "title": "Metabolic shutdown in Escherichia coli cells lacking the outer membrane channel TolC." }, { "docid": "14717500", "text": "Genome-wide association studies (GWAS) have now identified at least 2,000 common variants that appear associated with common diseases or related traits (http://www.genome.gov/gwastudies), hundreds of which have been convincingly replicated. It is generally thought that the associated markers reflect the effect of a nearby common (minor allele frequency >0.05) causal site, which is associated with the marker, leading to extensive resequencing efforts to find causal sites. We propose as an alternative explanation that variants much less common than the associated one may create \"synthetic associations\" by occurring, stochastically, more often in association with one of the alleles at the common site versus the other allele. Although synthetic associations are an obvious theoretical possibility, they have never been systematically explored as a possible explanation for GWAS findings. Here, we use simple computer simulations to show the conditions under which such synthetic associations will arise and how they may be recognized. We show that they are not only possible, but inevitable, and that under simple but reasonable genetic models, they are likely to account for or contribute to many of the recently identified signals reported in genome-wide association studies. We also illustrate the behavior of synthetic associations in real datasets by showing that rare causal mutations responsible for both hearing loss and sickle cell anemia create genome-wide significant synthetic associations, in the latter case extending over a 2.5-Mb interval encompassing scores of \"blocks\" of associated variants. In conclusion, uncommon or rare genetic variants can easily create synthetic associations that are credited to common variants, and this possibility requires careful consideration in the interpretation and follow up of GWAS signals.", "title": "Rare Variants Create Synthetic Genome-Wide Associations" }, { "docid": "1127562", "text": "Multicellular animals rapidly clear dying cells from their bodies. Many of the pathways that mediate this cell removal are conserved through evolution. Here, we identify srgp-1 as a negative regulator of cell clearance in both Caenorhabditis elegans and mammalian cells. Loss of srgp-1 function results in improved engulfment of apoptotic cells, whereas srgp-1 overexpression inhibits apoptotic cell corpse removal. We show that SRGP-1 functions in engulfing cells and functions as a GTPase activating protein (GAP) for CED-10 (Rac1). Interestingly, loss of srgp-1 function promotes not only the clearance of already dead cells, but also the removal of cells that have been brought to the verge of death through sublethal apoptotic, necrotic or cytotoxic insults. In contrast, impaired engulfment allows damaged cells to escape clearance, which results in increased long-term survival. We propose that C. elegans uses the engulfment machinery as part of a primitive, but evolutionarily conserved, survey mechanism that identifies and removes unfit cells within a tissue.", "title": "Loss of the RhoGAP SRGP-1 promotes the clearance of dead and injured cells in Caenorhabditis elegans" }, { "docid": "21164071", "text": "Integrins are membrane receptors which mediate cell-cell or cell-matrix adhesion. Integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) acts as a fibrinogen receptor of platelets and mediates platelet aggregation. Platelet activation is required for alpha IIb beta 3 to shift from noncompetent to competent for binding soluble fibrinogen. The steps involved in this transition are poorly understood. We have studied a variant of Glanzmann thrombasthenia, a congenital bleeding disorder characterized by absence of platelet aggregation and fibrinogen binding. The patient's platelets did not bind fibrinogen after platelet activation by ADP or thrombin, though his platelets contained alpha IIb beta 3. However, isolated alpha IIb beta 3 was able to bind to an Arg-Gly-Asp-Ser affinity column, and binding of soluble fibrinogen to the patient's platelets could be triggered by modulators of alpha IIb beta 3 conformation such as the Arg-Gly-Asp-Ser peptide and alpha-chymotrypsin. These data suggested that a functional Arg-Gly-Asp binding site was present within alpha IIb beta 3 and that the patient's defect was not secondary to a blockade of alpha IIb beta 3 in a noncompetent conformational state. This was evocative of a defect in the coupling between platelet activation and alpha IIb beta 3 up-regulation. We therefore sequenced the cytoplasmic domain of beta 3, following polymerase chain reaction (PCR) on platelet RNA, and found a T-->C mutation at nucleotide 2259, corresponding to a Ser-752-->Pro substitution. This mutation is likely to be responsible for the uncoupling of alpha IIb beta 3 from cellular activation because (i) it is not a polymorphism, (ii) it is the only mutation in the entire alpha IIb beta 3 sequence, and (iii) genetic analysis of the family showed that absence of the Pro-752 beta 3 allele was associated with the normal phenotype. Our data thus identify the C-terminal portion of the cytoplasmic domain of beta 3 as an intrinsic element in the coupling between alpha IIb beta 3 and platelet activation.", "title": "Ser-752-->Pro mutation in the cytoplasmic domain of integrin beta 3 subunit and defective activation of platelet integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) in a variant of Glanzmann thrombasthenia." }, { "docid": "10698739", "text": "Loss of Omi/HtrA2 function leads to nerve cell loss in mouse models and has been linked to neurodegeneration in Parkinson's and Huntington's disease. Omi/HtrA2 is a serine protease released as a pro-apoptotic factor from the mitochondrial intermembrane space into the cytosol. Under physiological conditions, Omi/HtrA2 is thought to be involved in protection against cellular stress, but the cytological and molecular mechanisms are not clear. Omi/HtrA2 deficiency caused an accumulation of reactive oxygen species and reduced mitochondrial membrane potential. In Omi/HtrA2 knockout mouse embryonic fibroblasts, as well as in Omi/HtrA2 silenced human HeLa cells and Drosophila S2R+ cells, we found elongated mitochondria by live cell imaging. Electron microscopy confirmed the mitochondrial morphology alterations and showed abnormal cristae structure. Examining the levels of proteins involved in mitochondrial fusion, we found a selective up-regulation of more soluble OPA1 protein. Complementation of knockout cells with wild-type Omi/HtrA2 but not with the protease mutant [S306A]Omi/HtrA2 reversed the mitochondrial elongation phenotype and OPA1 alterations. Finally, co-immunoprecipitation showed direct interaction of Omi/HtrA2 with endogenous OPA1. Thus, we show for the first time a direct effect of loss of Omi/HtrA2 on mitochondrial morphology and demonstrate a novel role of this mitochondrial serine protease in the modulation of OPA1. Our results underscore a critical role of impaired mitochondrial dynamics in neurodegenerative disorders.", "title": "Modulation of mitochondrial function and morphology by interaction of Omi/HtrA2 with the mitochondrial fusion factor OPA1." } ]

[ { "docid": "7898952", "text": "We have developed a nonheuristic genome topography scan (GTS) algorithm to characterize the patterns of genomic alterations in human glioblastoma (GBM), identifying frequent p18(INK4C) and p16(INK4A) codeletion. Functional reconstitution of p18(INK4C) in GBM cells null for both p16(INK4A) and p18(INK4C) resulted in impaired cell-cycle progression and tumorigenic potential. Conversely, RNAi-mediated depletion of p18(INK4C) in p16(INK4A)-deficient primary astrocytes or established GBM cells enhanced tumorigenicity in vitro and in vivo. Furthermore, acute suppression of p16(INK4A) in primary astrocytes induced a concomitant increase in p18(INK4C). Together, these findings uncover a feedback regulatory circuit in the astrocytic lineage and demonstrate a bona fide tumor suppressor role for p18(INK4C) in human GBM wherein it functions cooperatively with other INK4 family members to constrain inappropriate proliferation.", "title": "Feedback Circuit among INK4 Tumor Suppressors Constrains Human Glioblastoma Development" }, { "docid": "470625", "text": "Genomic alterations leading to aberrant activation of cyclin/cyclin-dependent kinase (cdk) complexes drive the pathogenesis of many common human tumor types. In the case of glioblastoma multiforme (GBM), these alterations are most commonly due to homozygous deletion of p16(INK4a) and less commonly due to genomic amplifications of individual genes encoding cyclins or cdks. Here, we describe deletion of the p18(INK4c) cdk inhibitor as a novel genetic alteration driving the pathogenesis of GBM. Deletions of p18(INK4c) often occurred in tumors also harboring homozygous deletions of p16(INK4a). Expression of p18(INK4c) was completely absent in 43% of GBM primary tumors studied by immunohistochemistry. Lentiviral reconstitution of p18(INK4c) expression at physiologic levels in p18(INK4c)-deficient but not p18(INK4c)-proficient GBM cells led to senescence-like G(1) cell cycle arrest. These studies identify p18(INK4c) as a GBM tumor suppressor gene, revealing an additional mechanism leading to aberrant activation of cyclin/cdk complexes in this terrible malignancy.", "title": "Identification of p18 INK4c as a tumor suppressor gene in glioblastoma multiforme." } ]

[ { "docid": "3127341", "text": "The glucagon-like peptide-1 receptor (GLP-1R) is a key physiological regulator of insulin secretion and a major therapeutic target for the treatment of type II diabetes. However, regulation of GLP-1R function is complex with multiple endogenous peptides that interact with the receptor, including full-length (1-37) and truncated (7-37) forms of GLP-1 that can exist in an amidated form (GLP-1(1-36)NH₂ and GLP-1(7-36)NH₂) and the related peptide oxyntomodulin. In addition, the GLP-1R possesses exogenous agonists, including exendin-4, and the allosteric modulator, compound 2 (6,7-dichloro-2-methylsulfonyl-3-tert-butylaminoquinoxaline). The complexity of this ligand-receptor system is further increased by the presence of several single nucleotide polymorphisms (SNPs) that are distributed across the receptor. We have investigated 10 GLP-1R SNPs, which were characterized in three physiologically relevant signaling pathways (cAMP accumulation, extracellular signal-regulated kinase 1/2 phosphorylation, and intracellular Ca²⁺ mobilization); ligand binding and cell surface receptor expression were also determined. We demonstrate both ligand- and pathway-specific effects for multiple SNPs, with the most dramatic effect observed for the Met¹⁴⁹ receptor variant. At the Met¹⁴⁹ variant, there was selective loss of peptide-induced responses across all pathways examined, but preservation of response to the small molecule compound 2. In contrast, at the Cys³³³ variant, peptide responses were preserved but there was attenuated response to compound 2. Strikingly, the loss of peptide function at the Met¹⁴⁹ receptor variant could be allosterically rescued by compound 2, providing proof-of-principle evidence that allosteric drugs could be used to treat patients with this loss of function variant.", "title": "Polymorphism and ligand dependent changes in human glucagon-like peptide-1 receptor (GLP-1R) function: allosteric rescue of loss of function mutation." }, { "docid": "4412772", "text": "Unicellular organisms such as yeasts require a single cyclin-dependent kinase, Cdk1, to drive cell division. In contrast, mammalian cells are thought to require the sequential activation of at least four different cyclin-dependent kinases, Cdk2, Cdk3, Cdk4 and Cdk6, to drive cells through interphase, as well as Cdk1 to proceed through mitosis. This model has been challenged by recent genetic evidence that mice survive in the absence of individual interphase Cdks. Moreover, most mouse cell types proliferate in the absence of two or even three interphase Cdks. Similar results have been obtained on ablation of some of the activating subunits of Cdks, such as the D-type and E-type cyclins. Here we show that mouse embryos lacking all interphase Cdks (Cdk2, Cdk3, Cdk4 and Cdk6) undergo organogenesis and develop to midgestation. In these embryos, Cdk1 binds to all cyclins, resulting in the phosphorylation of the retinoblastoma protein pRb and the expression of genes that are regulated by E2F transcription factors. Mouse embryonic fibroblasts derived from these embryos proliferate in vitro, albeit with an extended cell cycle due to inefficient inactivation of Rb proteins. However, they become immortal on continuous passage. We also report that embryos fail to develop to the morula and blastocyst stages in the absence of Cdk1. These results indicate that Cdk1 is the only essential cell cycle Cdk. Moreover, they show that in the absence of interphase Cdks, Cdk1 can execute all the events that are required to drive cell division.", "title": "Cdk1 is sufficient to drive the mammalian cell cycle" }, { "docid": "4414547", "text": "Improved sequencing technologies offer unprecedented opportunities for investigating the role of rare genetic variation in common disease. However, there are considerable challenges with respect to study design, data analysis and replication. Using pooled next-generation sequencing of 507 genes implicated in the repair of DNA in 1,150 samples, an analytical strategy focused on protein-truncating variants (PTVs) and a large-scale sequencing case–control replication experiment in 13,642 individuals, here we show that rare PTVs in the p53-inducible protein phosphatase PPM1D are associated with predisposition to breast cancer and ovarian cancer. PPM1D PTV mutations were present in 25 out of 7,781 cases versus 1 out of 5,861 controls (P = 1.12 × 10−5), including 18 mutations in 6,912 individuals with breast cancer (P = 2.42 × 10−4) and 12 mutations in 1,121 individuals with ovarian cancer (P = 3.10 × 10−9). Notably, all of the identified PPM1D PTVs were mosaic in lymphocyte DNA and clustered within a 370-base-pair region in the final exon of the gene, carboxy-terminal to the phosphatase catalytic domain. Functional studies demonstrate that the mutations result in enhanced suppression of p53 in response to ionizing radiation exposure, suggesting that the mutant alleles encode hyperactive PPM1D isoforms. Thus, although the mutations cause premature protein truncation, they do not result in the simple loss-of-function effect typically associated with this class of variant, but instead probably have a gain-of-function effect. Our results have implications for the detection and management of breast and ovarian cancer risk. More generally, these data provide new insights into the role of rare and of mosaic genetic variants in common conditions, and the use of sequencing in their identification.", "title": "Mosaic PPM1D mutations are associated with predisposition to breast and ovarian cancer" }, { "docid": "7717468", "text": "Microbial survival in a host is usually dependent on the ability of a pathogen to undergo changes that promote escape from host defense mechanisms. The human-pathogenic fungus Cryptococcus neoformans undergoes phenotypic switching in vivo that promotes persistence in tissue. By microarray and real-time PCR analyses, the allergen 1 gene (ALL1) was found to be downregulated in the hypervirulent mucoid switch variant, both during logarithmic growth and during intracellular growth in macrophages. The ALL1 gene encodes a small cytoplasmic protein that is involved in capsule formation. Growth of an all1Delta gene deletion mutant was normal. Similar to cells of the mucoid switch variant, all1Delta cells produced a larger polysaccharide capsule than cells of the smooth parent and the complemented strain produced, and the enlarged capsule inhibited macrophage phagocytosis. The mutant exhibited a modest defect in capsule induction compared to all of the other variants. In animal models the phenotype of the all1Delta mutant mimicked the hypervirulent phenotype of the mucoid switch variant, which is characterized by decreased host survival and elevated intracranial pressure. Decreased survival is likely the result of both an ineffective cell-mediated immune response and impaired phagocytosis by macrophages. Consequently, we concluded that, unlike loss of most virulence-associated genes, where loss of gene function results in attenuated virulence, loss of the ALL1 gene enhances virulence by altering the host-pathogen interaction and thereby impairing clearance. Our data identified the first cryptococcal gene associated with elevated intracranial pressure and support the hypothesis that an environmental opportunistic pathogen has modified its virulence in vivo by epigenetic downregulation of gene function.", "title": "Loss of allergen 1 confers a hypervirulent phenotype that resembles mucoid switch variants of Cryptococcus neoformans." }, { "docid": "344240", "text": "Actions of protein products resulting from alternative splicing of the Igf1 gene have received increasing attention in recent years. However, the significance and functional relevance of these observations remain poorly defined. To address functions of IGF-I splice variants, we examined the impact of loss of IGF-IEa and IGF-IEb on the proliferation and differentiation of cultured mouse myoblasts. RNA interference-mediated reductions in total IGF-I, IGF-IEa alone, or IGF-IEb alone had no effect on cell viability in growth medium. However, cells deficient in total IGF-I or IGF-IEa alone proliferated significantly slower than control cells or cells deficient in IGF-IEb in serum-free media. Simultaneous loss of both or specific loss of either splice variant significantly inhibited myosin heavy chain (MyHC) immunoreactivity by 70-80% (P < 0.01) under differentiation conditions (48 h in 2% horse serum) as determined by Western immunoblotting. This loss in protein was associated with reduced MyHC isoform mRNAs, because reductions in total IGF-I or IGF-IEa mRNA significantly reduced MyHC mRNAs by approximately 50-75% (P < 0.05). Loss of IGF-IEb also reduced MyHC isoform mRNA significantly, with the exception of Myh7, but to a lesser degree (∼20-40%, P < 0.05). Provision of mature IGF-I, but not synthetic E peptides, restored Myh3 expression to control levels in cells deficient in IGF-IEa or IGF-IEb. Collectively, these data suggest that IGF-I splice variants may regulate myoblast differentiation through the actions of mature IGF-I and not the E peptides.", "title": "Loss of IGF-IEa or IGF-IEb impairs myogenic differentiation." }, { "docid": "16626264", "text": "Histone variants help specialize chromatin regions; however, their impact on transcriptional regulation is largely unknown. Here, we determined the genome-wide localization and dynamics of Htz1, the yeast histone H2A variant. Htz1 localizes to hundreds of repressed/basal Pol II promoters and prefers TATA-less promoters. Specific Htz1 deposition requires the SWR1 complex, which largely colocalizes with Htz1. Htz1 occupancy correlates with particular histone modifications, and Htz1 deposition is partially reliant on Gcn5 (a histone acetyltransferase) and Bdf1, an SWR1 complex member that binds acetylated histones. Changes in growth conditions cause a striking redistribution of Htz1 from activated to repressed/basal promoters. Furthermore, Htz1 promotes full gene activation but does not generally impact repression. Importantly, Htz1 releases from purified chromatin in vitro under conditions where H2A and H3 remain associated. We suggest that Htz1-bearing nucleosomes are deposited at repressed/basal promoters but facilitate activation through their susceptibility to loss, thereby helping to expose promoter DNA.", "title": "Genome-Wide Dynamics of Htz1, a Histone H2A Variant that Poises Repressed/Basal Promoters for Activation through Histone Loss" }, { "docid": "4993011", "text": "ATRX (alpha thalassemia/mental retardation X-linked) complexes with DAXX to deposit histone variant H3.3 into repetitive heterochromatin. Recent genome sequencing studies in cancers have revealed mutations in ATRX and their association with ALT (alternative lengthening of telomeres) activation. Here we report depletion of ATRX in mouse ES cells leads to selective loss in ribosomal RNA gene (rDNA) copy number. Supporting this, ATRX-mutated human ALT-positive tumors also show a substantially lower rDNA copy than ALT-negative tumors. Further investigation shows that the rDNA copy loss and repeat instability are caused by a disruption in H3.3 deposition and thus a failure in heterochromatin formation at rDNA repeats in the absence of ATRX. We also find that ATRX-depleted cells are reduced in ribosomal RNA transcription output and show increased sensitivity to RNA polymerase I (Pol I) transcription inhibitor CX5461. In addition, human ALT-positive cancer cell lines are also more sensitive to CX5461 treatment. Our study provides insights into the contribution of ATRX loss of function to tumorigenesis through the loss of rDNA stability and suggests the therapeutic potential of targeting Pol I transcription in ALT cancers.", "title": "Ribosomal DNA copy loss and repeat instability in ATRX-mutated cancers" }, { "docid": "17518195", "text": "Histone variants within the H2A family show high divergences in their C-terminal regions. In this work, we have studied how these divergences and in particular, how a part of the H2A COOH-terminus, the docking domain, is implicated in both structural and functional properties of the nucleosome. Using biochemical methods in combination with Atomic Force Microscopy and Electron Cryo-Microscopy, we show that the H2A-docking domain is a key structural feature within the nucleosome. Deletion of this domain or replacement with the incomplete docking domain from the variant H2A.Bbd results in significant structural alterations in the nucleosome, including an increase in overall accessibility to nucleases, un-wrapping of ∼10 bp of DNA from each end of the nucleosome and associated changes in the entry/exit angle of DNA ends. These structural alterations are associated with a reduced ability of the chromatin remodeler RSC to both remodel and mobilize the nucleosomes. Linker histone H1 binding is also abrogated in nucleosomes containing the incomplete docking domain of H2A.Bbd. Our data illustrate the unique role of the H2A-docking domain in coordinating the structural-functional aspects of the nucleosome properties. Moreover, our data suggest that incorporation of a 'defective' docking domain may be a primary structural role of H2A.Bbd in chromatin.", "title": "The docking domain of histone H2A is required for H1 binding and RSC-mediated nucleosome remodeling" }, { "docid": "24311787", "text": "Variant histone H2AZ-containing nucleosomes are involved in the regulation of gene expression. In Saccharomyces cerevisiae, chromatin deposition of histone H2AZ is mediated by the fourteen-subunit SWR1 complex, which catalyzes ATP-dependent exchange of nucleosomal histone H2A for H2AZ. Previous work defined the role of seven SWR1 subunits (Swr1 ATPase, Swc2, Swc3, Arp6, Swc5, Yaf9, and Swc6) in maintaining complex integrity and H2AZ histone replacement activity. Here we examined the function of three additional SWR1 subunits, bromodomain containing Bdf1, actin-related protein Arp4 and Swc7, by analyzing affinity-purified mutant SWR1 complexes. We observed that depletion of Arp4 (arp4-td) substantially impaired the association of Bdf1, Yaf9, and Swc4. In contrast, loss of either Bdf1 or Swc7 had minimal effects on overall complex integrity. Furthermore, the basic H2AZ histone replacement activity of SWR1 in vitro required Arp4, but not Bdf1 or Swc7. Thus, three out of fourteen SWR1 subunits, Bdf1, Swc7, and previously noted Swc3, appear to have roles auxiliary to the basic histone replacement activity. The N-terminal region of the Swr1 ATPase subunit is necessary and sufficient to direct association of Bdf1 and Swc7, as well as Arp4, Act1, Yaf9 and Swc4. This same region contains an additional H2AZ-H2B specific binding site, distinct from the previously identified Swc2 subunit. These findings suggest that one SWR1 enzyme might be capable of binding two H2AZ-H2B dimers, and provide further insight on the hierarchy and interdependency of molecular interactions within the SWR1 complex.", "title": "N terminus of Swr1 binds to histone H2AZ and provides a platform for subunit assembly in the chromatin remodeling complex." }, { "docid": "43220289", "text": "Extreme obesity is associated with severe psychiatric and somatic comorbidity and impairment of psychosocial functioning. Bariatric surgery is the most effective treatment not only with regard to weight loss but also with obesity-associated illnesses. Health-related psychological and psychosocial variables have been increasingly considered as important outcome variables of bariatric surgery. However, the long-term impact of bariatric surgery on psychological and psychosocial functioning is largely unclear. The aim of this study was to evaluate the relationship between the course of weight and psychological variables including depression, anxiety, health-related quality of life (HRQOL), and self-esteem up to 4 years after obesity surgery. By standardized questionnaires prior to (T1) and 1 year (T2), 2 years (T3), and 4 years (T4) after surgery, 148 patients (47 males (31.8 %), 101 females (68.2 %), mean age 38.8 ± 10.2 years) were assessed. On average, participants lost 24.6 % of their initial weight 1 year after surgery, 25.1 % after 2 years, and 22.3 % after 4 years. Statistical analysis revealed significant improvements in depressive symptoms, physical dimension of quality of life, and self-esteem with peak improvements 1 year after surgery. These improvements were largely maintained. Significant correlations between weight loss and improvements in depression, physical aspects of HRQOL (T2, T3, and T4), and self-esteem (T3) were observed. Corresponding to the considerable weight loss after bariatric surgery, important aspects of mental health improved significantly during the 4-year follow-up period. However, parallel to weight regain, psychological improvements showed a slow but not significant decline over time.", "title": "Psychological Outcome 4 Years after Restrictive Bariatric Surgery" }, { "docid": "14717500", "text": "Genome-wide association studies (GWAS) have now identified at least 2,000 common variants that appear associated with common diseases or related traits (http://www.genome.gov/gwastudies), hundreds of which have been convincingly replicated. It is generally thought that the associated markers reflect the effect of a nearby common (minor allele frequency >0.05) causal site, which is associated with the marker, leading to extensive resequencing efforts to find causal sites. We propose as an alternative explanation that variants much less common than the associated one may create \"synthetic associations\" by occurring, stochastically, more often in association with one of the alleles at the common site versus the other allele. Although synthetic associations are an obvious theoretical possibility, they have never been systematically explored as a possible explanation for GWAS findings. Here, we use simple computer simulations to show the conditions under which such synthetic associations will arise and how they may be recognized. We show that they are not only possible, but inevitable, and that under simple but reasonable genetic models, they are likely to account for or contribute to many of the recently identified signals reported in genome-wide association studies. We also illustrate the behavior of synthetic associations in real datasets by showing that rare causal mutations responsible for both hearing loss and sickle cell anemia create genome-wide significant synthetic associations, in the latter case extending over a 2.5-Mb interval encompassing scores of \"blocks\" of associated variants. In conclusion, uncommon or rare genetic variants can easily create synthetic associations that are credited to common variants, and this possibility requires careful consideration in the interpretation and follow up of GWAS signals.", "title": "Rare Variants Create Synthetic Genome-Wide Associations" }, { "docid": "21164071", "text": "Integrins are membrane receptors which mediate cell-cell or cell-matrix adhesion. Integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) acts as a fibrinogen receptor of platelets and mediates platelet aggregation. Platelet activation is required for alpha IIb beta 3 to shift from noncompetent to competent for binding soluble fibrinogen. The steps involved in this transition are poorly understood. We have studied a variant of Glanzmann thrombasthenia, a congenital bleeding disorder characterized by absence of platelet aggregation and fibrinogen binding. The patient's platelets did not bind fibrinogen after platelet activation by ADP or thrombin, though his platelets contained alpha IIb beta 3. However, isolated alpha IIb beta 3 was able to bind to an Arg-Gly-Asp-Ser affinity column, and binding of soluble fibrinogen to the patient's platelets could be triggered by modulators of alpha IIb beta 3 conformation such as the Arg-Gly-Asp-Ser peptide and alpha-chymotrypsin. These data suggested that a functional Arg-Gly-Asp binding site was present within alpha IIb beta 3 and that the patient's defect was not secondary to a blockade of alpha IIb beta 3 in a noncompetent conformational state. This was evocative of a defect in the coupling between platelet activation and alpha IIb beta 3 up-regulation. We therefore sequenced the cytoplasmic domain of beta 3, following polymerase chain reaction (PCR) on platelet RNA, and found a T-->C mutation at nucleotide 2259, corresponding to a Ser-752-->Pro substitution. This mutation is likely to be responsible for the uncoupling of alpha IIb beta 3 from cellular activation because (i) it is not a polymorphism, (ii) it is the only mutation in the entire alpha IIb beta 3 sequence, and (iii) genetic analysis of the family showed that absence of the Pro-752 beta 3 allele was associated with the normal phenotype. Our data thus identify the C-terminal portion of the cytoplasmic domain of beta 3 as an intrinsic element in the coupling between alpha IIb beta 3 and platelet activation.", "title": "Ser-752-->Pro mutation in the cytoplasmic domain of integrin beta 3 subunit and defective activation of platelet integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) in a variant of Glanzmann thrombasthenia." }, { "docid": "13777706", "text": "Polycomb repressor complexes (PRCs) are important chromatin modifiers fundamentally implicated in pluripotency and cancer. Polycomb silencing in embryonic stem cells (ESCs) can be accompanied by active chromatin and primed RNA polymerase II (RNAPII), but the relationship between PRCs and RNAPII remains unclear genome-wide. We mapped PRC repression markers and four RNAPII states in ESCs using ChIP-seq, and found that PRC targets exhibit a range of RNAPII variants. First, developmental PRC targets are bound by unproductive RNAPII (S5p(+)S7p(-)S2p(-)) genome-wide. Sequential ChIP, Ring1B depletion, and genome-wide correlations show that PRCs and RNAPII-S5p physically bind to the same chromatin and functionally synergize. Second, we identify a cohort of genes marked by PRC and elongating RNAPII (S5p(+)S7p(+)S2p(+)); they produce mRNA and protein, and their expression increases upon PRC1 knockdown. We show that this group of PRC targets switches between active and PRC-repressed states within the ESC population, and that many have roles in metabolism.", "title": "Polycomb Associates Genome-wide with a Specific RNA Polymerase II Variant, and Regulates Metabolic Genes in ESCs" }, { "docid": "4455466", "text": "Recognition of modified histones by ‘reader’ proteins plays a critical role in the regulation of chromatin. H3K36 trimethylation (H3K36me3) is deposited onto the nucleosomes in the transcribed regions after RNA polymerase II elongation. In yeast, this mark in turn recruits epigenetic regulators to reset the chromatin to a relatively repressive state, thus suppressing cryptic transcription. However, much less is known about the role of H3K36me3 in transcription regulation in mammals. This is further complicated by the transcription-coupled incorporation of the histone variant H3.3 in gene bodies. Here we show that the candidate tumour suppressor ZMYND11 specifically recognizes H3K36me3 on H3.3 (H3.3K36me3) and regulates RNA polymerase II elongation. Structural studies show that in addition to the trimethyl-lysine binding by an aromatic cage within the PWWP domain, the H3.3-dependent recognition is mediated by the encapsulation of the H3.3-specific ‘Ser 31’ residue in a composite pocket formed by the tandem bromo–PWWP domains of ZMYND11. Chromatin immunoprecipitation followed by sequencing shows a genome-wide co-localization of ZMYND11 with H3K36me3 and H3.3 in gene bodies, and its occupancy requires the pre-deposition of H3.3K36me3. Although ZMYND11 is associated with highly expressed genes, it functions as an unconventional transcription co-repressor by modulating RNA polymerase II at the elongation stage. ZMYND11 is critical for the repression of a transcriptional program that is essential for tumour cell growth; low expression levels of ZMYND11 in breast cancer patients correlate with worse prognosis. Consistently, overexpression of ZMYND11 suppresses cancer cell growth in vitro and tumour formation in mice. Together, this study identifies ZMYND11 as an H3.3-specific reader of H3K36me3 that links the histone-variant-mediated transcription elongation control to tumour suppression.", "title": "ZMYND11 links histone H3.3K36me3 to transcription elongation and tumour suppression" }, { "docid": "23117928", "text": "Infection of Sulfolobus islandicus REY15A with mixtures of different Sulfolobus viruses, including STSV2, did not induce spacer acquisition by the host CRISPR immune system. However, coinfection with the tailed fusiform viruses SMV1 and STSV2 generated hyperactive spacer acquisition in both CRISPR loci, exclusively from STSV2, with the resultant loss of STSV2 but not SMV1. SMV1 was shown to activate adaptation while itself being resistant to CRISPR-mediated adaptation and DNA interference. Exceptionally, a single clone S-1 isolated from an SMV1 + STSV2-infected culture, that carried STSV2-specific spacers and had lost STSV2 but not SMV1, acquired spacers from SMV1. This effect was also reproducible on reinfecting wild-type host cells with a variant SMV1 isolated from the S-1 culture. The SMV1 variant lacked a virion protein ORF114 that was shown to bind DNA. This study also provided evidence for: (i) limits on the maximum sizes of CRISPR loci; (ii) spacer uptake strongly retarding growth of infected cultures; (iii) protospacer selection being essentially random and non-directional, and (iv) the reversible uptake of spacers from STSV2 and SMV1. A hypothesis is presented to explain the interactive conflicts between SMV1 and the host CRISPR immune system.", "title": "Inter-viral conflicts that exploit host CRISPR immune systems of Sulfolobus." }, { "docid": "1127562", "text": "Multicellular animals rapidly clear dying cells from their bodies. Many of the pathways that mediate this cell removal are conserved through evolution. Here, we identify srgp-1 as a negative regulator of cell clearance in both Caenorhabditis elegans and mammalian cells. Loss of srgp-1 function results in improved engulfment of apoptotic cells, whereas srgp-1 overexpression inhibits apoptotic cell corpse removal. We show that SRGP-1 functions in engulfing cells and functions as a GTPase activating protein (GAP) for CED-10 (Rac1). Interestingly, loss of srgp-1 function promotes not only the clearance of already dead cells, but also the removal of cells that have been brought to the verge of death through sublethal apoptotic, necrotic or cytotoxic insults. In contrast, impaired engulfment allows damaged cells to escape clearance, which results in increased long-term survival. We propose that C. elegans uses the engulfment machinery as part of a primitive, but evolutionarily conserved, survey mechanism that identifies and removes unfit cells within a tissue.", "title": "Loss of the RhoGAP SRGP-1 promotes the clearance of dead and injured cells in Caenorhabditis elegans" }, { "docid": "10279084", "text": "MAP kinase phosphatase-2 (MKP-2) is a member of the family of dual specificity phosphatases that functions to inactivate the ERK and JNK MAP kinase signalling pathways. Here, we identify a novel human MKP-2 variant (MKP-2-S) lacking the MAP kinase binding site but retaining the phosphatase catalytic domain. Endogenous MKP-2-S transcripts and proteins were found in PC3 prostate and MDA-MB-231 breast cancer cells and also human prostate biopsies. Cellular transfection of MKP-2-S gave rise to a nuclear protein of 33kDa which displayed phosphatase activity comparable to the formerly described long form of MKP-2 (MKP-2-L). Due to its lack of a kinase interacting motif (KIM), MKP-2-S did not bind to JNK or ERK; MKP-2-L bound ERK and to a lesser extent JNK. Protein turnover of adenoviral expressed MKP-2-S was accelerated relative to MKP-2-L, with a greater susceptibility to proteosomal-mediated degradation. MKP-2-S retained its ability to deactivate JNK in a similar manner as MKP-2-L and was an effective inhibitor of LPS-stimulated COX-2 induction. However, unlike MKP-2-L, MKP-2-S was unable to reverse serum-induced ERK activation or significantly inhibit endothelial cell proliferation. These findings reveal the occurrence of a novel splice variant of MKP-2 which is unable to bind ERK and may be significant in the dysregulation of MAP kinase activity in certain disease states, particularly in breast and prostate cancers.", "title": "Differential regulation of MAP kinase activation by a novel splice variant of human MAP kinase phosphatase-2." }, { "docid": "23698769", "text": "DNA polymerase μ (Pol μ) is the only template-dependent human DNA polymerase capable of repairing double-strand DNA breaks (DSBs) with unpaired 3′ ends in nonhomologous end joining (NHEJ). To probe this function, we structurally characterized Pol μ's catalytic cycle for single-nucleotide incorporation. These structures indicate that, unlike other template-dependent DNA polymerases, Pol μ shows no large-scale conformational changes in protein subdomains, amino acid side chains or DNA upon dNTP binding or catalysis. Instead, the only major conformational change is seen earlier in the catalytic cycle, when the flexible loop 1 region repositions upon DNA binding. Pol μ variants with changes in loop 1 have altered catalytic properties and are partially defective in NHEJ. The results indicate that specific loop 1 residues contribute to Pol μ's unique ability to catalyze template-dependent NHEJ of DSBs with unpaired 3′ ends.", "title": "Sustained active site rigidity during synthesis by human DNA polymerase μ" } ]

[ { "docid": "32587939", "text": "Endoplasmic reticulum (ER) stress causes pancreatic β-cell dysfunction and contributes to β-cell loss and the progression of type 2 diabetes. Wolfram syndrome 1 (WFS1) has been shown to be an important regulator of the ER stress signalling pathway; however, its role in β-cell function remains unclear. Here we provide evidence that WFS1 is essential for glucose- and glucagon-like peptide 1 (GLP-1)-stimulated cyclic AMP production and regulation of insulin biosynthesis and secretion. Stimulation with glucose causes WFS1 translocation from the ER to the plasma membrane, where it forms a complex with adenylyl cyclase 8 (AC8), an essential cAMP-generating enzyme in the β-cell that integrates glucose and GLP-1 signalling. ER stress and mutant WFS1 inhibit complex formation and activation of AC8, reducing cAMP synthesis and insulin secretion. These findings reveal that an ER-stress-related protein has a distinct role outside the ER regulating both insulin biosynthesis and secretion. The reduction of WFS1 protein on the plasma membrane during ER stress is a contributing factor for β-cell dysfunction and progression of type 2 diabetes.", "title": "Wolfram syndrome 1 and adenylyl cyclase 8 interact at the plasma membrane to regulate insulin production and secretion" } ]

[ { "docid": "25510546", "text": "Increased lipid supply causes beta cell death, which may contribute to reduced beta cell mass in type 2 diabetes. We investigated whether endoplasmic reticulum (ER) stress is necessary for lipid-induced apoptosis in beta cells and also whether ER stress is present in islets of an animal model of diabetes and of humans with type 2 diabetes. Expression of genes involved in ER stress was evaluated in insulin-secreting MIN6 cells exposed to elevated lipids, in islets isolated from db/db mice and in pancreas sections of humans with type 2 diabetes. Overproduction of the ER chaperone heat shock 70 kDa protein 5 (HSPA5, previously known as immunoglobulin heavy chain binding protein [BIP]) was performed to assess whether attenuation of ER stress affected lipid-induced apoptosis. We demonstrated that the pro-apoptotic fatty acid palmitate triggers a comprehensive ER stress response in MIN6 cells, which was virtually absent using non-apoptotic fatty acid oleate. Time-dependent increases in mRNA levels for activating transcription factor 4 (Atf4), DNA-damage inducible transcript 3 (Ddit3, previously known as C/EBP homologous protein [Chop]) and DnaJ homologue (HSP40) C3 (Dnajc3, previously known as p58) correlated with increased apoptosis in palmitate- but not in oleate-treated MIN6 cells. Attenuation of ER stress by overproduction of HSPA5 in MIN6 cells significantly protected against lipid-induced apoptosis. In islets of db/db mice, a variety of marker genes of ER stress were also upregulated. Increased processing (activation) of X-box binding protein 1 (Xbp1) mRNA was also observed, confirming the existence of ER stress. Finally, we observed increased islet protein production of HSPA5, DDIT3, DNAJC3 and BCL2-associated X protein in human pancreas sections of type 2 diabetes subjects. Our results provide evidence that ER stress occurs in type 2 diabetes and is required for aspects of the underlying beta cell failure.", "title": "Endoplasmic reticulum stress contributes to beta cell apoptosis in type 2 diabetes" }, { "docid": "35760786", "text": "The ARV1-encoded protein mediates sterol transport from the endoplasmic reticulum (ER) to the plasma membrane. Yeast ARV1 mutants accumulate multiple lipids in the ER and are sensitive to pharmacological modulators of both sterol and sphingolipid metabolism. Using fluorescent and electron microscopy, we demonstrate sterol accumulation, subcellular membrane expansion, elevated lipid droplet formation, and vacuolar fragmentation in ARV1 mutants. Motif-based regression analysis of ARV1 deletion transcription profiles indicates activation of Hac1p, an integral component of the unfolded protein response (UPR). Accordingly, we show constitutive splicing of HAC1 transcripts, induction of a UPR reporter, and elevated expression of UPR targets in ARV1 mutants. IRE1, encoding the unfolded protein sensor in the ER lumen, exhibits a lethal genetic interaction with ARV1, indicating a viability requirement for the UPR in cells lacking ARV1. Surprisingly, ARV1 mutants expressing a variant of Ire1p defective in sensing unfolded proteins are viable. Moreover, these strains also exhibit constitutive HAC1 splicing that interacts with DTT-mediated perturbation of protein folding. These data suggest that a component of UPR induction in arv1Δ strains is distinct from protein misfolding. Decreased ARV1 expression in murine macrophages also results in UPR induction, particularly up-regulation of activating transcription factor-4, CHOP (C/EBP homologous protein), and apoptosis. Cholesterol loading or inhibition of cholesterol esterification further elevated CHOP expression in ARV1 knockdown cells. Thus, loss or down-regulation of ARV1 disturbs membrane and lipid homeostasis, resulting in a disruption of ER integrity, one consequence of which is induction of the UPR.", "title": "Loss of subcellular lipid transport due to ARV1 deficiency disrupts organelle homeostasis and activates the unfolded protein response." }, { "docid": "4911006", "text": "Apoptotic cells have long been considered as intrinsically tolerogenic or unable to elicit immune responses specific for dead cell-associated antigens. However, multiple stimuli can trigger a functionally peculiar type of apoptotic demise that does not go unnoticed by the adaptive arm of the immune system, which we named \"immunogenic cell death\" (ICD). ICD is preceded or accompanied by the emission of a series of immunostimulatory damage-associated molecular patterns (DAMPs) in a precise spatiotemporal configuration. Several anticancer agents that have been successfully employed in the clinic for decades, including various chemotherapeutics and radiotherapy, can elicit ICD. Moreover, defects in the components that underlie the capacity of the immune system to perceive cell death as immunogenic negatively influence disease outcome among cancer patients treated with ICD inducers. Thus, ICD has profound clinical and therapeutic implications. Unfortunately, the gold-standard approach to detect ICD relies on vaccination experiments involving immunocompetent murine models and syngeneic cancer cells, an approach that is incompatible with large screening campaigns. Here, we outline strategies conceived to detect surrogate markers of ICD in vitro and to screen large chemical libraries for putative ICD inducers, based on a high-content, high-throughput platform that we recently developed. Such a platform allows for the detection of multiple DAMPs, like cell surface-exposed calreticulin, extracellular ATP and high mobility group box 1 (HMGB1), and/or the processes that underlie their emission, such as endoplasmic reticulum stress, autophagy and necrotic plasma membrane permeabilization. We surmise that this technology will facilitate the development of next-generation anticancer regimens, which kill malignant cells and simultaneously convert them into a cancer-specific therapeutic vaccine.", "title": "Consensus guidelines for the detection of immunogenic cell death." }, { "docid": "13780287", "text": "When cells are activated by calcium-mobilizing agonists at low, physiological concentrations, the resulting calcium signals generally take the form of repetitive regenerative discharges of stored calcium, termed calcium oscillations [1]. These intracellular calcium oscillations have long fascinated biologists as a mode of digitized intracellular signaling. Recent work has highlighted the role of calcium influx as an essential component of calcium oscillations [2]. This influx occurs through a process known as store-operated calcium entry, which is initiated by calcium sensor proteins, STIM1 and STIM2, in the endoplasmic reticulum [3]. STIM2 is activated by changes in endoplasmic reticulum calcium near the resting level, whereas a threshold of calcium depletion is required for STIM1 activation [4]. Here we show that, surprisingly, it is STIM1 and not STIM2 that is exclusively involved in calcium entry during calcium oscillations. The implication is that each oscillation produces a transient drop in endoplasmic reticulum calcium and that this drop is sufficient to transiently activate STIM1. This transient activation of STIM1 can be observed in some cells by total internal reflection fluorescence microscopy. This arrangement nicely provides a clearly defined and unambiguous signaling system, translating a digital calcium release signal into calcium influx that can signal to downstream effectors.", "title": "STIM1 Is a Calcium Sensor Specialized for Digital Signaling" }, { "docid": "29459383", "text": "The major histocompatibility complex class I molecules display peptides (pMHC I) on the cell surface for immune surveillance by CD8(+) T cells. These peptides are generated by proteolysis of intracellular polypeptides by the proteasome in the cytoplasm and then in the endoplasmic reticulum (ER) by the ER aminopeptidase associated with antigen processing (ERAAP). To define the unknown mechanism of ERAAP function in vivo, we analyzed naturally processed peptides in cells with or without appropriate MHC I and ERAAP. In the absence of MHC I, ERAAP degraded the antigenic precursors in the ER. However, MHC I molecules could bind proteolytic intermediates and were essential for generation of the final peptide by ERAAP. Thus, ERAAP synergizes with MHC I to generate the final pMHC I repertoire.", "title": "ERAAP synergizes with MHC class I molecules to make the final cut in the antigenic peptide precursors in the endoplasmic reticulum." }, { "docid": "4399311", "text": "An inflammatory response initiated by the NLRP3 inflammasome is triggered by a variety of situations of host ‘danger’, including infection and metabolic dysregulation. Previous studies suggested that NLRP3 inflammasome activity is negatively regulated by autophagy and positively regulated by reactive oxygen species (ROS) derived from an uncharacterized organelle. Here we show that mitophagy/autophagy blockade leads to the accumulation of damaged, ROS-generating mitochondria, and this in turn activates the NLRP3 inflammasome. Resting NLRP3 localizes to endoplasmic reticulum structures, whereas on inflammasome activation both NLRP3 and its adaptor ASC redistribute to the perinuclear space where they co-localize with endoplasmic reticulum and mitochondria organelle clusters. Notably, both ROS generation and inflammasome activation are suppressed when mitochondrial activity is dysregulated by inhibition of the voltage-dependent anion channel. This indicates that NLRP3 inflammasome senses mitochondrial dysfunction and may explain the frequent association of mitochondrial damage with inflammatory diseases.", "title": "A role for mitochondria in NLRP3 inflammasome activation" }, { "docid": "19561411", "text": "Orai1 and stromal interaction molecule 1 (STIM1) mediate store-operated Ca(2+) entry (SOCE) in immune cells. STIM1, an endoplasmic reticulum (ER) Ca(2+) sensor, detects store depletion and interacts with plasma membrane (PM)-resident Orai1 channels at the ER-PM junctions. However, the molecular composition of these junctions in T cells remains poorly understood. Here, we show that junctophilin-4 (JP4), a member of junctional proteins in excitable cells, is expressed in T cells and localized at the ER-PM junctions to regulate Ca(2+) signaling. Silencing or genetic manipulation of JP4 decreased ER Ca(2+) content and SOCE in T cells, impaired activation of the nuclear factor of activated T cells (NFAT) and extracellular signaling-related kinase (ERK) signaling pathways, and diminished expression of activation markers and cytokines. Mechanistically, JP4 directly interacted with STIM1 via its cytoplasmic domain and facilitated its recruitment into the junctions. Accordingly, expression of this cytoplasmic fragment of JP4 inhibited SOCE. Furthermore, JP4 also formed a complex with junctate, a Ca(2+)-sensing ER-resident protein, previously shown to mediate STIM1 recruitment into the junctions. We propose that the junctate-JP4 complex located at the junctions cooperatively interacts with STIM1 to maintain ER Ca(2+) homeostasis and mediate SOCE in T cells.", "title": "Junctophilin-4, a component of the endoplasmic reticulum-plasma membrane junctions, regulates Ca2+ dynamics in T cells." }, { "docid": "20904154", "text": "Cu/Zn-superoxide dismutase is misfolded in familial and sporadic amyotrophic lateral sclerosis, but it is not clear how this triggers endoplasmic reticulum (ER) stress or other pathogenic processes. Here, we demonstrate that mutant SOD1 (mSOD1) is predominantly found in the cytoplasm in neuronal cells. Furthermore, we show that mSOD1 inhibits secretory protein transport from the ER to Golgi apparatus. ER-Golgi transport is linked to ER stress, Golgi fragmentation and axonal transport and we also show that inhibition of ER-Golgi trafficking preceded ER stress, Golgi fragmentation, protein aggregation and apoptosis in cells expressing mSOD1. Restoration of ER-Golgi transport by over-expression of coatomer coat protein II subunit Sar1 protected against inclusion formation and apoptosis, thus linking dysfunction in ER-Golgi transport to cellular pathology. These findings thus link several cellular events in amyotrophic lateral sclerosis into a single mechanism occurring early in mSOD1 expressing cells.", "title": "Mutant SOD1 inhibits ER-Golgi transport in amyotrophic lateral sclerosis." }, { "docid": "7482674", "text": "Pelizaeus-Merzbacher disease (PMD) is a form of X-linked leukodystrophy caused by mutations in the proteolipid protein 1 (PLP1) gene. Although PLP1 proteins with missense mutations have been shown to accumulate in the rough endoplasmic reticulum (ER) in disease model animals and cell lines transfected with mutant PLP1 genes, the exact pathogenetic mechanism of PMD has not previously been clarified. In this study, we established induced pluripotent stem cells (iPSCs) from two PMD patients carrying missense mutation and differentiated them into oligodendrocytes in vitro. In the PMD iPSC-derived oligodendrocytes, mislocalization of mutant PLP1 proteins to the ER and an association between increased susceptibility to ER stress and increased numbers of apoptotic oligodendrocytes were observed. Moreover, electron microscopic analysis demonstrated drastically reduced myelin formation accompanied by abnormal ER morphology. Thus, this study demonstrates the involvement of ER stress in pathogenic dysmyelination in the oligodendrocytes of PMD patients with the PLP1 missense mutation.", "title": "Involvement of ER Stress in Dysmyelination of Pelizaeus-Merzbacher Disease with PLP1 Missense Mutations Shown by iPSC-Derived Oligodendrocytes" }, { "docid": "13958154", "text": "Pancreatic β-cell dysfunction and death are central in the pathogenesis of type 2 diabetes (T2D). Saturated fatty acids cause β-cell failure and contribute to diabetes development in genetically predisposed individuals. Here we used RNA sequencing to map transcripts expressed in five palmitate-treated human islet preparations, observing 1,325 modified genes. Palmitate induced fatty acid metabolism and endoplasmic reticulum (ER) stress. Functional studies identified novel mediators of adaptive ER stress signaling. Palmitate modified genes regulating ubiquitin and proteasome function, autophagy, and apoptosis. Inhibition of autophagic flux and lysosome function contributed to lipotoxicity. Palmitate inhibited transcription factors controlling β-cell phenotype, including PAX4 and GATA6. Fifty-nine T2D candidate genes were expressed in human islets, and 11 were modified by palmitate. Palmitate modified expression of 17 splicing factors and shifted alternative splicing of 3,525 transcripts. Ingenuity Pathway Analysis of modified transcripts and genes confirmed that top changed functions related to cell death. Database for Annotation, Visualization and Integrated Discovery (DAVID) analysis of transcription factor binding sites in palmitate-modified transcripts revealed a role for PAX4, GATA, and the ER stress response regulators XBP1 and ATF6. This human islet transcriptome study identified novel mechanisms of palmitate-induced β-cell dysfunction and death. The data point to cross talk between metabolic stress and candidate genes at the β-cell level.", "title": "RNA sequencing identifies dysregulation of the human pancreatic islet transcriptome by the saturated fatty acid palmitate." }, { "docid": "19708993", "text": "Mucolipidosis type IV is an autosomal recessive lysosomal storage disorder characterized by severe neurodegeneration, achlorhydria, and visual impairments such as corneal opacity and strabismus. The disease arises due to mutations in a group 2 transient receptor potential (TRP)-related cation channel, TRPML1. Mammals encode two additional TRPML proteins named TRPML2 and TRPML3. Information regarding the propensity of these proteins to multimerize, their subcellular distribution and mechanisms that regulate their trafficking are limited. Here we demonstrate that TRPMLs interact to form homo- and heteromultimers. Moreover, the presence of either TRPML1 or TRPML2 specifically influences the spatial distribution of TRPML3. TRPML1 and TRPML2 homomultimers are lysosomal proteins, whereas TRPML3 homomultimers are in the endoplasmic reticulum. However, TRPML3 localizes to lysosomes when coexpressed with either TRPML1 or TRPML2 and is comparably mislocalized when lysosomal targeting of TRPML1 and TRPML2 is disrupted. Conversely, TRPML3 does not cause retention of TRPML1 or TRPML2 in the endoplasmic reticulum. These data demonstrate that there is a hierarchy controlling the subcellular distributions of the TRPMLs such that TRPML1 and TRPML2 dictate the localization of TRPML3 and not vice versa.", "title": "Lysosomal localization of TRPML3 depends on TRPML2 and the mucolipidosis-associated protein TRPML1." }, { "docid": "8453819", "text": "The integrin family of heterodimeric cell-surface receptors are fundamental in cell-cell and cell-matrix adhesion. Changes to either integrin-ligand affinity or integrin gene expression are central to a variety of disease processes, including inflammation, cardiovascular disease and cancer. In screening for novel activators of integrin-ligand affinity we identified the previously uncharacterised multi-transmembrane domain protein Fam38A, located at the endoplasmic reticulum (ER). siRNA knockdown of Fam38A in epithelial cells inactivates endogenous beta1 integrin, reducing cell adhesion. Fam38A mediates integrin activation by recruiting the small GTPase R-Ras to the ER, which activates the calcium-activated protease calpain by increasing Ca(2+) release from cytoplasmic stores. Fam38A-induced integrin activation is blocked by inhibition of either R-Ras or calpain activity, or by siRNA knockdown of talin, a well-described calpain substrate. This highlights a novel mechanism for integrin activation by Fam38A, utilising calpain and R-Ras signalling from the ER. These data represent the first description of a novel spatial regulator of R-Ras, of an alternative integrin activation-suppression pathway based on direct relocalisation of R-Ras to the ER, and of a mechanism linking R-Ras and calpain signalling from the ER with modulation of integrin-ligand affinity.", "title": "Integrin activation by Fam38A uses a novel mechanism of R-Ras targeting to the endoplasmic reticulum." }, { "docid": "9752604", "text": "In light of the emerging interplay between redox and metabolic signaling pathways we investigated the potential cross talk between nuclear factor E2-related factor 2 (Nrf2) and AMP-activated kinase (AMPK), central regulators of the cellular redox and energy balance, respectively. Making use of xanthohumol (XN) as an activator of both the AMPK and the Nrf2 signaling pathway we show that AMPK exerts a positive influence on Nrf2/heme oxygenase (HO)-1 signaling in mouse embryonic fibroblasts. Genetic ablation and pharmacological inhibition of AMPK blunts Nrf2-dependent HO-1 expression by XN already at the mRNA level. XN leads to AMPK activation via interference with mitochondrial function and activation of liver kinase B1 as upstream AMPK kinase. The subsequent AMPK-mediated enhancement of the Nrf2/HO-1 response does not depend on inhibition of the mammalian target of rapamycin, inhibition of glycogen synthase kinase 3β, or altered abundance of Nrf2 (total and nuclear). However, reduced endoplasmic reticulum stress was identified and elaborated as a step in the AMPK-augmented Nrf2/HO-1 response. Overall, we shed more light on the hitherto incompletely understood cross talk between the LKB1/AMPK and the Nrf2/HO-1 axis revealing for the first time involvement of the unfolded protein response as an additional player and suggesting tight cooperation between signaling pathways controlling cellular redox, energy, or protein homeostasis.", "title": "Activated AMPK boosts the Nrf2/HO-1 signaling axis—A role for the unfolded protein response" }, { "docid": "15716328", "text": "Endoplasmic reticulum (ER)-associated aminopeptidase (ERAP)1 has been implicated in the final proteolytic processing of peptides presented by major histocompatibility complex (MHC) class I molecules. To evaluate the in vivo role of ERAP1, we have generated ERAP1-deficient mice. Cell surface expression of the class Ia molecules H-2Kb and H-2Db and of the class Ib molecule Qa-2 was significantly reduced in these animals. Although cells from mutant animals exhibited reduced capacity to present several self- and foreign antigens to Kb-, Db-, or Qa-1b–restricted CD8+ cytotoxic T cells, presentation of some antigens was unaffected or significantly enhanced. Consistent with these findings, mice generated defective CD8+ T cell responses against class I–presented antigens. These findings reveal an important in vivo role of ER-associated peptidase activity in tailoring peptides for presentation by MHC class Ia and class Ib molecules.", "title": "In vivo role of ER-associated peptidase activity in tailoring peptides for presentation by MHC class Ia and class Ib molecules" }, { "docid": "38477436", "text": "Human cytomegalovirus US2 and US11 target newly synthesized class I major histocompatibility complex (MHC) heavy chains for rapid degradation by the proteasome through a process termed dislocation. The presence of US2 induces the formation of class I MHC heavy chain conjugates of increased molecular weight that are recognized by a conformation-specific monoclonal antibody, W6/32, suggesting that these class I MHC molecules retain their proper tertiary structure. These conjugates are properly folded glycosylated heavy chains modified by attachment of an estimated one, two, and three ubiquitin molecules. The folded ubiquitinated class I MHC heavy chains are not observed in control cells or in cells transfected with US11, suggesting that US2 targets class I MHC heavy chains for dislocation in a manner distinct from that used by US11. This is further supported by the fact that US2 and US11 show different requirements in terms of the conformation of the heavy chain molecule. Although ubiquitin conjugation may occur on the cytosolic tail of the class I MHC molecule, replacement of lysines in the cytosolic tail of heavy chains with arginine does not prevent their degradation by US2. In an in vitro system that recapitulates US2-mediated dislocation, heavy chains that lack these lysines still occur in an ubiquitin-modified form, but in the soluble (cytoplasmic) fraction. Such ubiquitin conjugation can only occur on the class I MHC lumenal domain and is likely to take place once class I MHC heavy chains have been discharged from the endoplasmic reticulum. We conclude that ubiquitinylation of class I MHC heavy chain is not required during the initial step of the US2-mediated dislocation reaction.", "title": "Ubiquitinylation of the cytosolic domain of a type I membrane protein is not required to initiate its dislocation from the endoplasmic reticulum." }, { "docid": "42873134", "text": "Type 1 and type 2 diabetes are characterized by progressive beta-cell failure. Apoptosis is probably the main form of beta-cell death in both forms of the disease. It has been suggested that the mechanisms leading to nutrient- and cytokine-induced beta-cell death in type 2 and type 1 diabetes, respectively, share the activation of a final common pathway involving interleukin (IL)-1beta, nuclear factor (NF)-kappaB, and Fas. We review herein the similarities and differences between the mechanisms of beta-cell death in type 1 and type 2 diabetes. In the insulitis lesion in type 1 diabetes, invading immune cells produce cytokines, such as IL-1beta, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma. IL-1beta and/or TNF-alpha plus IFN-gamma induce beta-cell apoptosis via the activation of beta-cell gene networks under the control of the transcription factors NF-kappaB and STAT-1. NF-kappaB activation leads to production of nitric oxide (NO) and chemokines and depletion of endoplasmic reticulum (ER) calcium. The execution of beta-cell death occurs through activation of mitogen-activated protein kinases, via triggering of ER stress and by the release of mitochondrial death signals. Chronic exposure to elevated levels of glucose and free fatty acids (FFAs) causes beta-cell dysfunction and may induce beta-cell apoptosis in type 2 diabetes. Exposure to high glucose has dual effects, triggering initially \"glucose hypersensitization\" and later apoptosis, via different mechanisms. High glucose, however, does not induce or activate IL-1beta, NF-kappaB, or inducible nitric oxide synthase in rat or human beta-cells in vitro or in vivo in Psammomys obesus. FFAs may cause beta-cell apoptosis via ER stress, which is NF-kappaB and NO independent. Thus, cytokines and nutrients trigger beta-cell death by fundamentally different mechanisms, namely an NF-kappaB-dependent mechanism that culminates in caspase-3 activation for cytokines and an NF-kappaB-independent mechanism for nutrients. This argues against a unifying hypothesis for the mechanisms of beta-cell death in type 1 and type 2 diabetes and suggests that different approaches will be required to prevent beta-cell death in type 1 and type 2 diabetes.", "title": "Mechanisms of pancreatic beta-cell death in type 1 and type 2 diabetes: many differences, few similarities." }, { "docid": "600437", "text": "VAP (VAPA and VAPB) is an evolutionarily conserved endoplasmic reticulum (ER)-anchored protein that helps generate tethers between the ER and other membranes through which lipids are exchanged across adjacent bilayers. Here, we report that by regulating PI4P levels on endosomes, VAP affects WASH-dependent actin nucleation on these organelles and the function of the retromer, a protein coat responsible for endosome-to-Golgi traffic. VAP is recruited to retromer budding sites on endosomes via an interaction with the retromer SNX2 subunit. Cells lacking VAP accumulate high levels of PI4P, actin comets, and trans-Golgi proteins on endosomes. Such defects are mimicked by downregulation of OSBP, a VAP interactor and PI4P transporter that participates in VAP-dependent ER-endosomes tethers. These results reveal a role of PI4P in retromer-/WASH-dependent budding from endosomes. Collectively, our data show how the ER can control budding dynamics and association with the cytoskeleton of another membrane by direct contacts leading to bilayer lipid modifications.", "title": "Endosome-ER Contacts Control Actin Nucleation and Retromer Function through VAP-Dependent Regulation of PI4P" }, { "docid": "24670522", "text": "The intracellular Ca(2+) concentration of many nonexcitable cells is regulated by calcium store release and store-operated calcium entry (SOCE). In platelets, STIM1 was recently identified as the main calcium sensor expressed in the endoplasmic reticulum. To evaluate the role of the SOC channel moiety, Orai1, in platelet SOCE, we generated mice expressing a mutated, inactive form of Orai1 in blood cells only (Orai1(R93W)). Platelets expressing Orai1(R93W) were characterized by markedly reduced SOCE and impaired agonist-induced increases in [Ca(2+)](i). Orai1(R93W) platelets showed reduced integrin activation and impaired degranulation when stimulated with low agonist concentrations under static conditions. This defect, however, did not significantly affect the ability of Orai1(R93W) platelets to aggregate or to adhere to collagen under arterial flow conditions ex vivo. In contrast, these adherent Orai1(R93W) platelets were defective in surface phosphatidylserine exposure, suggesting that Orai1 is crucial for the platelets' procoagulant response rather than for other Ca(2+)-dependent cellular responses.", "title": "R93W mutation in Orai1 causes impaired calcium influx in platelets." }, { "docid": "23304931", "text": "PURPOSE Diffuse large B-cell lymphoma (DLBCL) represents a clinically heterogeneous disease. Models based on immunohistochemistry predict clinical outcome. These include subdivision into germinal center (GC) versus non-GC subtypes; proliferation index (measured by expression of Ki-67), and expression of BCL-2, FOXP1, or B-lymphocyte-induced maturation protein (Blimp-1)/PRDM1. We sought to determine whether immunohistochemical analyses of biopsies from patients with DLBCL having HIV infection are similarly relevant for prognosis. \n PATIENTS AND METHODS We examined 81 DLBCLs from patients with AIDS in AMC010 (cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP] v CHOP-rituximab) and AMC034 (etoposide, doxorubicin, vincristine, prednisone, and dose-adjusted cyclophosphamide plus rituximab concurrent v sequential) clinical trials and compared the immunophenotype with survival data, Epstein-Barr virus (EBV) positivity, and CD4 counts. \n RESULTS The GC and non-GC subtypes of DLBCL did not differ significantly with respect to overall survival or CD4 count at cancer presentation. EBV could be found in both subtypes of DLBCL, although less frequently in the GC subtype, and did not affect survival. Expression of FOXP1, Blimp-1/PRDM1, or BCL-2 was not correlated with the outcome in patients with AIDS-related DLBCL. \n CONCLUSION These data indicate that with current treatment strategies for lymphoma and control of HIV infection, commonly used immunohistochemical markers may not be clinically relevant in HIV-infected patients with DLBCL. The only predictive immunohistochemical marker was found to be Ki-67, where a higher proliferation index was associated with better survival, suggesting a better response to therapy in patients whose tumors had higher proliferation rates.", "title": "Immunophenotypic analysis of AIDS-related diffuse large B-cell lymphoma and clinical implications in patients from AIDS malignancies consortium clinical trials 010 and 034" } ]

[ { "docid": "13794374", "text": "Lipid droplets are ubiquitous triglyceride and sterol ester storage organelles required for energy storage homeostasis and biosynthesis. Although little is known about lipid droplet formation and regulation, it is clear that members of the PAT (perilipin, adipocyte differentiation related protein, tail interacting protein of 47 kDa) protein family coat the droplet surface and mediate interactions with lipases that remobilize the stored lipids. We identified key Drosophila candidate genes for lipid droplet regulation by RNA interference (RNAi) screening with an image segmentation-based optical read-out system, and show that these regulatory functions are conserved in the mouse. Those include the vesicle-mediated Coat Protein Complex I (COPI) transport complex, which is required for limiting lipid storage. We found that COPI components regulate the PAT protein composition at the lipid droplet surface, and promote the association of adipocyte triglyceride lipase (ATGL) with the lipid droplet surface to mediate lipolysis. Two compounds known to inhibit COPI function, Exo1 and Brefeldin A, phenocopy COPI knockdowns. Furthermore, RNAi inhibition of ATGL and simultaneous drug treatment indicate that COPI and ATGL function in the same pathway. These data indicate that the COPI complex is an evolutionarily conserved regulator of lipid homeostasis, and highlight an interaction between vesicle transport systems and lipid droplets.", "title": "COPI Complex Is a Regulator of Lipid Homeostasis" } ]

[ { "docid": "21547032", "text": "Objective:In mice and in humans, treatment with the second-generation antipsychotic drug olanzapine (OLZ) produces excessive weight gain, adiposity and secondary metabolic complications, including loss of glucose and insulin homeostasis. In mice consuming a high-fat (HF) diet, a similar phenotype develops, which is inhibited by the analgesic acetaminophen (APAP) and by the antioxidant tetrahydroindenoindole (THII). Therefore, we examined the ability of APAP and THII to prevent metabolic changes in mice receiving OLZ.Design and Measurement:C57BL/6J mice received either a normal diet or a HF diet, and were administered daily dosages of OLZ (3 mg kg−1 body weight), alone or with APAP (30 mg kg−1 body weight) or THII (4.5 mg kg−1 body weight), for 10 weeks. Parameters of body composition and metabolism, including glucose and insulin homeostasis and oxidative stress, were examined. Results:OLZ treatment doubled the HF diet-induced increases in body weight and percent body fat. These increases were partially prevented by both APAP and THII, although food consumption was constant in all groups. The THII protection was associated with an increase in whole body and mitochondrial respiration. OLZ also exacerbated, and both APAP and THII prevented, HF diet-induced loss of glucose tolerance and insulin resistance. As increased body fat promotes insulin resistance by a pathway involving oxidative stress, we evaluated production of reactive oxygen and lipid peroxidation in white adipose tissue (WAT). HF diet caused an increase in lipid peroxidation, NADPH-dependent O2 uptake and H2O2 production, which were further exacerbated by OLZ. APAP, THII and the NADPH oxidase inhibitor, diphenyleneiodonium chloride, each abolished oxidative stress in WAT.Conclusions:We conclude that both APAP and THII intervene in the development of obesity and metabolic complications associated with OLZ treatment.", "title": "Protection from olanzapine-induced metabolic toxicity in mice by acetaminophen and tetrahydroindenoindole" }, { "docid": "8458567", "text": "PEROXISOMES are cytoplasmic organelles which are important in mammals in modulation of lipid homeostasis, including the metabolism of long-chain fatty acids and conversion of cholesterol to bile salts (reviewed in refs 1 and 2). Amphipathic carboxylates such as clofibric acid have been used in man as hypolipidaemic agents and in rodents they stimulate the proliferation of peroxisomes. These agents, termed peroxisome proliferators, and all-trans retinoic acid activate genes involved in peroxisomal-mediated β-oxidation of fatty acids1–4. Here we show that the receptor activated by peroxisome proliferators5 and the retinoid X receptor-α (ref. 6) form a heterodimer that activates acyl-CoA oxidase gene expression in response to either clofibric acid or the retinoid X receptor-α ligand, 9-cis retinoic acid, an all-trans retinoic acid metabolite7,8; simultaneous exposure to both activators results in a synergistic induction of gene expression. These data demonstrate the coupling of the peroxisome proliferator and retinoid signalling pathways and provide evidence for a physiological role for 9-cis retinoic acid in modulating lipid metabolism.", "title": "Convergence of 9-cis retinoic acid and peroxisome proliferator signalling pathways through heterodimer formation of their receptors" }, { "docid": "31154082", "text": "Dehydrins (DHNs; late embryogenesis abundant D-11) are a family of plant proteins induced in response to abiotic stresses such as drought, low temperature, and salinity or during the late stages of embryogenesis. Spectral and thermal properties of these proteins in purified form suggest that they are \"intrinsically unstructured. \" However, DHNs contain at least one copy of a consensus 15-amino acid sequence, the \"K segment,\" which resembles a class A2 amphipathic alpha-helical, lipid-binding domain found in other proteins such as apolipoproteins and alpha-synuclein. The presence of the K segment raises the question of whether DHNs bind lipids, bilayers, or phospholipid vesicles. Here, we show that maize (Zea mays) DHN DHN1 can bind to lipid vesicles that contain acidic phospholipids. We also observe that DHN1 binds more favorably to vesicles of smaller diameter than to larger vesicles, and that the association of DHN1 with vesicles results in an apparent increase of alpha-helicity of the protein. Therefore, DHNs, and presumably somewhat similar plant stress proteins in the late embryogenesis abundant and cold-regulated classes may undergo function-related conformational changes at the water/membrane interface, perhaps related to the stabilization of vesicles or other endomembrane structures under stress conditions.", "title": "The binding of maize DHN1 to lipid vesicles. Gain of structure and lipid specificity." }, { "docid": "11742219", "text": "Galanin (GAL) is known to stimulate feeding behavior. This peptide has different properties and functions from other feeding stimulants, e.g., neuropeptide Y and agouti-related protein. Hypothalamic GAL is relatively unresponsive to food deprivation and to changes in corticosterone, glucose utilization, dietary carbohydrate and leptin. This indicates that this peptide is not essential under conditions when food is scarce or low-energy, high-carbohydrate diets are being consumed. In contrast, recent evidence suggests that GAL in the paraventricular nucleus (PVN) functions in close relation to dietary fat and alcohol. In particular, it mediates functions that allow animals to adapt to conditions of positive energy balance involving excess consumption of these nutrients. This peptide in the PVN is stimulated by a high-fat diet and also by alcohol. It is stimulated by an increase in circulating lipids caused by a fat-rich meal or alcohol consumption, and it rises during the middle of the active feeding cycle, when fat consumption and triglycerides naturally rise. When centrally injected, GAL in the PVN increases the consumption of food and alcohol. Moreover, it produces a significantly stronger feeding response in rats maintained on a fat-rich diet, which also promotes alcohol intake. This evidence supports the existence of non-homeostatic, positive feedback circuits between GAL and both dietary fat and alcohol. These circuits are believed to contribute to the large meal size, over-consumption of alcohol, and obesity which are generally associated with fat-rich foods.", "title": "Regulation and effects of hypothalamic galanin: relation to dietary fat, alcohol ingestion, circulating lipids and energy homeostasis." }, { "docid": "35760786", "text": "The ARV1-encoded protein mediates sterol transport from the endoplasmic reticulum (ER) to the plasma membrane. Yeast ARV1 mutants accumulate multiple lipids in the ER and are sensitive to pharmacological modulators of both sterol and sphingolipid metabolism. Using fluorescent and electron microscopy, we demonstrate sterol accumulation, subcellular membrane expansion, elevated lipid droplet formation, and vacuolar fragmentation in ARV1 mutants. Motif-based regression analysis of ARV1 deletion transcription profiles indicates activation of Hac1p, an integral component of the unfolded protein response (UPR). Accordingly, we show constitutive splicing of HAC1 transcripts, induction of a UPR reporter, and elevated expression of UPR targets in ARV1 mutants. IRE1, encoding the unfolded protein sensor in the ER lumen, exhibits a lethal genetic interaction with ARV1, indicating a viability requirement for the UPR in cells lacking ARV1. Surprisingly, ARV1 mutants expressing a variant of Ire1p defective in sensing unfolded proteins are viable. Moreover, these strains also exhibit constitutive HAC1 splicing that interacts with DTT-mediated perturbation of protein folding. These data suggest that a component of UPR induction in arv1Δ strains is distinct from protein misfolding. Decreased ARV1 expression in murine macrophages also results in UPR induction, particularly up-regulation of activating transcription factor-4, CHOP (C/EBP homologous protein), and apoptosis. Cholesterol loading or inhibition of cholesterol esterification further elevated CHOP expression in ARV1 knockdown cells. Thus, loss or down-regulation of ARV1 disturbs membrane and lipid homeostasis, resulting in a disruption of ER integrity, one consequence of which is induction of the UPR.", "title": "Loss of subcellular lipid transport due to ARV1 deficiency disrupts organelle homeostasis and activates the unfolded protein response." }, { "docid": "33569870", "text": "The physiological role of autophagic flux within the vascular endothelial layer remains poorly understood. Here, we show that in primary endothelial cells, oxidized and native LDL stimulates autophagosome formation. Moreover, by both confocal and electron microscopy, excess native or modified LDL appears to be engulfed within autophagic structures. Transient knockdown of the essential autophagy gene ATG7 resulted in higher levels of intracellular (125) I-LDL and oxidized LDL (OxLDL) accumulation, suggesting that in endothelial cells, autophagy may represent an important mechanism to regulate excess, exogenous lipids. The physiological importance of these observations was assessed using mice containing a conditional deletion of ATG7 within the endothelium. Following acute intravenous infusion of fluorescently labeled OxLDL, mice lacking endothelial expression of ATG7 demonstrated prolonged retention of OxLDL within the retinal pigment epithelium (RPE) and choroidal endothelium of the eye. In a chronic model of lipid excess, we analyzed atherosclerotic burden in ApoE(-/-) mice with or without endothelial autophagic flux. The absence of endothelial autophagy markedly increased atherosclerotic burden. Thus, in both an acute and chronic in vivo model, endothelial autophagy appears critically important in limiting lipid accumulation within the vessel wall. As such, strategies that stimulate autophagy, or prevent the age-dependent decline in autophagic flux, might be particularly beneficial in treating atherosclerotic vascular disease.", "title": "Intact endothelial autophagy is required to maintain vascular lipid homeostasis." }, { "docid": "18199839", "text": "BACKGROUND Persistent inflammation has been proposed to contribute to various stages in the pathogenesis of cardiovascular disease. Interleukin-6 receptor (IL6R) signalling propagates downstream inflammation cascades. To assess whether this pathway is causally relevant to coronary heart disease, we studied a functional genetic variant known to affect IL6R signalling. \n METHODS In a collaborative meta-analysis, we studied Asp358Ala (rs2228145) in IL6R in relation to a panel of conventional risk factors and inflammation biomarkers in 125,222 participants. We also compared the frequency of Asp358Ala in 51,441 patients with coronary heart disease and in 136,226 controls. To gain insight into possible mechanisms, we assessed Asp358Ala in relation to localised gene expression and to postlipopolysaccharide stimulation of interleukin 6. \n FINDINGS The minor allele frequency of Asp358Ala was 39%. Asp358Ala was not associated with lipid concentrations, blood pressure, adiposity, dysglycaemia, or smoking (p value for association per minor allele ≥0·04 for each). By contrast, for every copy of 358Ala inherited, mean concentration of IL6R increased by 34·3% (95% CI 30·4-38·2) and of interleukin 6 by 14·6% (10·7-18·4), and mean concentration of C-reactive protein was reduced by 7·5% (5·9-9·1) and of fibrinogen by 1·0% (0·7-1·3). For every copy of 358Ala inherited, risk of coronary heart disease was reduced by 3·4% (1·8-5·0). Asp358Ala was not related to IL6R mRNA levels or interleukin-6 production in monocytes. \n INTERPRETATION Large-scale human genetic and biomarker data are consistent with a causal association between IL6R-related pathways and coronary heart disease. \n FUNDING British Heart Foundation; UK Medical Research Council; UK National Institute of Health Research, Cambridge Biomedical Research Centre; BUPA Foundation.", "title": "Interleukin-6 receptor pathways in coronary heart disease: a collaborative meta-analysis of 82 studies" }, { "docid": "38025907", "text": "Nonalcoholic fatty liver disease (NAFLD) is an increasingly prevalent chronic liver disease for which no approved therapies are available. Despite intensive research, the cellular mechanisms that mediate NAFLD pathogenesis and progression are poorly understood. Although obesity, diabetes, insulin resistance, and related metabolic syndrome, all consequences of a Western diet lifestyle, are well-recognized risk factors for NAFLD development, dysregulated bile acid metabolism is emerging as a novel mechanism contributing to NAFLD pathogenesis. Notably, NAFLD patients exhibit a deficiency in fibroblast growth factor 19 (FGF19), an endocrine hormone in the gut-liver axis that controls de novo bile acid synthesis, lipogenesis, and energy homeostasis. Using a mouse model that reproduces the clinical progression of human NAFLD, including the development of simple steatosis, nonalcoholic steatohepatitis (NASH), and advanced \"burnt-out\" NASH with hepatocellular carcinoma, we demonstrate that FGF19 as well as an engineered nontumorigenic FGF19 analogue, M70, ameliorate bile acid toxicity and lipotoxicity to restore liver health. Mass spectrometry-based lipidomics analysis of livers from mice treated with FGF19 or M70 revealed significant reductions in the levels of toxic lipid species (i.e., diacylglycerols, ceramides and free cholesterol) and an increase in levels of unoxidized cardiolipins, an important component of the inner mitochondrial membrane. Furthermore, treatment with FGF19 or M70 rapidly and profoundly reduced levels of liver enzymes, resolved the histologic features of NASH, and enhanced insulin sensitivity, energy homeostasis, and lipid metabolism. Whereas FGF19 induced hepatocellular carcinoma formation following prolonged exposure in these mice, animals expressing M70 showed no evidence of liver tumorigenesis in this model. Conclusion: We have engineered an FGF19 hormone that is capable of regulating multiple pathways to deliver antisteatotic, anti-inflammatory, and antifibrotic activities and that represents a potentially promising therapeutic for patients with NASH. (Hepatology Communications 2017;1:1024-1042).", "title": "Engineered FGF19 eliminates bile acid toxicity and lipotoxicity leading to resolution of steatohepatitis and fibrosis in mice" }, { "docid": "14116046", "text": "Retinoic acid-related orphan receptors RORα and RORγ play a regulatory role in lipid/glucose homeostasis and various immune functions, and have been implicated in metabolic syndrome and several inflammatory diseases. RORα-deficient mice are protected against age- and diet-induced obesity, hepatosteatosis, and insulin resistance. The resistance to hepatosteatosis in RORα-deficient mice is related to the reduced expression of several genes regulating lipid synthesis, transport, and storage. Adipose tissue-associated inflammation, which plays a critical role in the development of insulin resistance, is considerably diminished in RORα-deficient mice as indicated by the reduced infiltration of M1 macrophages and decreased expression of many proinflammatory genes. Deficiency in RORγ also protects against diet-induced insulin resistance by a mechanism that appears different from that in RORα deficiency. Recent studies indicated that RORs provide an important link between the circadian clock machinery and its regulation of metabolic genes and metabolic syndrome. As ligand-dependent transcription factors, RORs may provide novel therapeutic targets in the management of obesity and associated metabolic diseases, including hepatosteatosis, adipose tissue-associated inflammation, and insulin resistance.", "title": "Retinoic acid-related orphan receptors α and γ: key regulators of lipid/glucose metabolism, inflammation, and insulin sensitivity" }, { "docid": "20288322", "text": "In the 20th century industrialized nations have become afflicted with an unprecedented pandemic of increased adiposity. In the United States, the epicenter of the epidemic, over 2/3 of the population, is overweight and 1 of every 6 Americans carries the diagnosis of metabolic syndrome. Although genes determine susceptibility to environmental factors, the epidemic is clearly due to increased consumption of calorie-dense, highly lipogenic foods, coupled with a marked decrease in physical exertion resulting from modern technologies. If this lifestyle continues, morbid consequences are virtually inevitable. They include type II diabetes and a cluster of disorders known as \"the metabolic syndrome\" usually appearing in middle age. The morbid consequences of the chronic caloric surplus are buffered before middle age by the partitioning of these calories as fat in the adipocyte compartment which is specifically designed to store triglycerides. Leptin has been proposed as the major hormonal regulator of the partitioning of surplus calories. However, multiple factors can determine the storage capacity of the fat tissue and when it is exceeded ectopic lipid deposition begins. The organs affected in metabolic syndrome include skeletal muscle, liver, heart and pancreas, which are now known to contain abnormal levels of triglycerides. While neutral fat is probably harmless, it is an index of ectopic lipid overload. Fatty acid derivatives can interfere with the function of the cell and ultimately lead to its demise through lipoapoptosis, the consequences of which are gradual organ failure.", "title": "Lipid homeostasis, lipotoxicity and the metabolic syndrome." }, { "docid": "6588614", "text": "Diabetes and associated metabolic conditions have reached pandemic proportions worldwide, and there is a clear unmet medical need for new therapies that are both effective and safe. FGF19 and FGF21 are distinctive members of the FGF family that function as endocrine hormones. Both have potent effects on normalizing glucose, lipid, and energy homeostasis, and therefore, represent attractive potential next generation therapies for combating the growing epidemics of type 2 diabetes and obesity. The mechanism responsible for these impressive metabolic effects remains unknown. While both FGF19 and FGF21 can activate FGFRs 1c, 2c, and 3c in the presence of co-receptor βKlotho in vitro, which receptor is responsible for the metabolic activities observed in vivo remains unknown. Here we have generated a variant of FGF19, FGF19-7, that has altered receptor specificity with a strong bias toward FGFR1c. We show that FGF19-7 is equally efficacious as wild type FGF19 in regulating glucose, lipid, and energy metabolism in both diet-induced obesity and leptin-deficient mouse models. These results are the first direct demonstration of the central role of the βKlotho/FGFR1c receptor complex in glucose and lipid regulation, and also strongly suggest that activation of this receptor complex alone might be sufficient to achieve all the metabolic functions of endocrine FGF molecules.", "title": "Characterization of a FGF19 Variant with Altered Receptor Specificity Revealed a Central Role for FGFR1c in the Regulation of Glucose Metabolism" }, { "docid": "13573143", "text": "Comparative Gene Identification-58 (CGI-58), a lipid droplet (LD)-associated protein, promotes intracellular triglyceride (TG) hydrolysis in vitro. Mutations in human CGI-58 cause TG accumulation in numerous tissues including intestine. Enterocytes are thought not to store TG-rich LDs, but a fatty meal does induce temporary cytosolic accumulation of LDs. Accumulated LDs are eventually cleared out, implying existence of TG hydrolytic machinery in enterocytes. However, identities of proteins responsible for LD-TG hydrolysis remain unknown. Here we report that intestine-specific inactivation of CGI-58 in mice significantly reduces postprandial plasma TG concentrations and intestinal TG hydrolase activity, which is associated with a 4-fold increase in intestinal TG content and large cytosolic LD accumulation in absorptive enterocytes during the fasting state. Intestine-specific CGI-58 knockout mice also display mild yet significant decreases in intestinal fatty acid absorption and oxidation. Surprisingly, inactivation of CGI-58 in intestine significantly raises plasma and intestinal cholesterol, and reduces hepatic cholesterol, without altering intestinal cholesterol absorption and fecal neutral sterol excretion. In conclusion, intestinal CGI-58 is required for efficient postprandial lipoprotein-TG secretion and for maintaining hepatic and plasma lipid homeostasis. Our animal model will serve as a valuable tool to further define how intestinal fat metabolism influences the pathogenesis of metabolic disorders, such as obesity and type 2 diabetes.", "title": "Intestinal Cgi-58 Deficiency Reduces Postprandial Lipid Absorption" }, { "docid": "25462689", "text": "We have investigated HO endonuclease-induced double-strand break (DSB) recombination and repair in a LACZ duplication plasmid in yeast. A 117-bp MATa fragment, embedded in one copy of LACZ, served as a site for initiation of a DSB when HO endonuclease was expressed. The DSB could be repaired using wild-type sequences located on a second, promoterless, copy of LACZ on the same plasmid. In contrast to normal mating-type switching, crossing-over associated with gene conversion occurred at least 50% of the time. The proportion of conversion events accompanied by exchange was greater when the two copies of LACZ were in direct orientation (80%), than when inverted (50%). In addition, the fraction of plasmids lost was significantly greater in the inverted orientation. The kinetics of appearance of intermediates and final products were also monitored. The repair of the DSB is slow, requiring at least an hour from the detection of the HO-cut fragments to completion of repair. Surprisingly, the appearance of the two reciprocal products of crossing over did not occur with the same kinetics. For example, when the two LACZ sequences were in the direct orientation, the HO-induced formation of a large circular deletion product was not accompanied by the appearance of a small circular reciprocal product. We suggest that these differences may reflect two kinetically separable processes, one involving only one cut end and the other resulting from the concerted participation of both ends of the DSB.", "title": "Genetic and physical analysis of double-strand break repair and recombination in Saccharomyces cerevisiae." }, { "docid": "4325398", "text": "Pancreatic cancer is a highly lethal malignancy with few effective therapies. We performed exome sequencing and copy number analysis to define genomic aberrations in a prospectively accrued clinical cohort (n = 142) of early (stage I and II) sporadic pancreatic ductal adenocarcinoma. Detailed analysis of 99 informative tumours identified substantial heterogeneity with 2,016 non-silent mutations and 1,628 copy-number variations. We define 16 significantly mutated genes, reaffirming known mutations (KRAS, TP53, CDKN2A, SMAD4, MLL3, TGFBR2, ARID1A and SF3B1), and uncover novel mutated genes including additional genes involved in chromatin modification (EPC1 and ARID2), DNA damage repair (ATM) and other mechanisms (ZIM2, MAP2K4, NALCN, SLC16A4 and MAGEA6). Integrative analysis with in vitro functional data and animal models provided supportive evidence for potential roles for these genetic aberrations in carcinogenesis. Pathway-based analysis of recurrently mutated genes recapitulated clustering in core signalling pathways in pancreatic ductal adenocarcinoma, and identified new mutated genes in each pathway. We also identified frequent and diverse somatic aberrations in genes described traditionally as embryonic regulators of axon guidance, particularly SLIT/ROBO signalling, which was also evident in murine Sleeping Beauty transposon-mediated somatic mutagenesis models of pancreatic cancer, providing further supportive evidence for the potential involvement of axon guidance genes in pancreatic carcinogenesis.", "title": "Pancreatic cancer genomes reveal aberrations in axon guidance pathway genes" }, { "docid": "2605032", "text": "We investigated if whether intrauterine protein restriction in combination with overfeeding during lactation would cause adult-onset obesity and metabolic disorders. After birth, litters from dams fed with control (17% protein) and low protein (6% protein) diets were adjusted to a size of four (CO and LO groups, respectively) or eight (CC and LC groups, respectively) pups. All of the offspring were fed a diet containing 12% protein from the time of weaning until they were 90 d old. Compared to the CC and LC groups, the CO and LO groups had higher relative and absolute food intakes, oxygen consumption and carbon dioxide production; lower brown adipose tissue weight and lipid content and greater weight gain and absolute and relative white adipose tissue weight and absolute lipid content. Compared with the CO and CC rats, the LC and LO rats exhibited higher relative food intake, brown adipose tissue weight and lipid content, reduced oxygen consumption, carbon dioxide production and spontaneous activity, increased relative retroperitoneal adipose tissue weight and unaltered absolute white adipose tissue weight and lipid content. The fasting serum glucose was similar among the groups. The area under the glucose curve was higher in the LO and CO rats than in the LC and CC rats. The basal insulinemia and homeostasis model assessment of insulin resistance (HOMA-IR) were lower in the LO group than in the other groups. The total area under the insulin curve for the LO rats was similar to the CC rats, and both were lower than the CO and LC rats. Kitt was higher in the LO, LC and CO groups than in the CC group. Thus, intrauterine protein restriction followed by overfeeding during lactation did not induce obesity, but produced glucose intolerance by impairing pancreatic function in adulthood.", "title": "Intrauterine protein restriction combined with early postnatal overfeeding was not associated with adult-onset obesity but produced glucose intolerance by pancreatic dysfunction" }, { "docid": "6903077", "text": "In single-stranded ribonucleic acid (RNA) viruses, virus capsid assembly and genome packaging are intertwined processes. Using cryo-electron microscopy and single particle analysis we determined the asymmetric virion structure of bacteriophage MS2, which includes 178 copies of the coat protein, a single copy of the A-protein and the RNA genome. This reveals that in situ, the viral RNA genome can adopt a defined conformation. The RNA forms a branched network of stem-loops that almost all allocate near the capsid inner surface, while predominantly binding to coat protein dimers that are located in one-half of the capsid. This suggests that genomic RNA is highly involved in genome packaging and virion assembly.", "title": "Asymmetric cryo-EM reconstruction of phage MS2 reveals genome structure in situ" }, { "docid": "31564409", "text": "Objectives:The orexigenic hormone ghrelin circulates mainly in two forms, acylated and desacyl ghrelin. We evaluated the impact of obesity and obesity-associated type 2 diabetes (T2D) on ghrelin forms and the potential role of acylated and desacyl ghrelin in the control of adipogenesis in humans. Methods:Plasma concentrations of the different ghrelin forms were measured in 80 subjects. The expression of the ghrelin receptor (growth hormone secretagogue receptor, GHS-R) was analyzed in omental adipose tissue using western blot and immunohistochemistry, and the effect of acylated ghrelin and desacyl ghrelin (0.1–1000 pmol l−1) on adipogenesis was determined in vitro in omental adipocytes. Results:Circulating concentrations of acylated ghrelin were increased, whereas desacyl ghrelin levels were decreased, in obesity and obesity-associated T2D. Body mass index, waist circumference, insulin and HOMA (homeostasis model assessment) index were positively correlated with acylated ghrelin levels. Obese individuals showed a lower protein expression of GHS-R in omental adipose tissue. In differentiating omental adipocytes, incubation with both acylated and desacyl ghrelin significantly increased PPARγ (peroxisome proliferator-activated receptor γ) and SREBP1 (sterol-regulatory element binding protein-1) mRNA levels, as well as several fat storage-related proteins, including acetyl-CoA carboxylase, fatty acid synthase, lipoprotein lipase and perilipin. Consequently, both the ghrelin forms stimulated intracytoplasmatic lipid accumulation. Conclusions:Both acylated and desacyl ghrelin stimulate lipid accumulation in human visceral adipocytes. Given the lipogenic effect of acylated ghrelin on visceral adipocytes, the herein-reported elevation of its circulating concentrations in obese individuals may play a role in excessive fat accumulation in obesity.", "title": "Acylated and desacyl ghrelin stimulate lipid accumulation in human visceral adipocytes" }, { "docid": "22674621", "text": "Farnesoid X receptor (FXR), a bile-acid-activated member of the nuclear receptor superfamily, is essential in regulating bile-acid, cholesterol, and triglyceride homeostasis. Disruption of the FXR gene in mice results in a proatherosclerotic lipid profile with increased serum cholesterols and triglycerides. However, the role of FXR in foam-cell formation and atherosclerosis development remains unclear. The current study showed that the peritoneal macrophages isolated from FXR-null mice took up less oxidized LDL-cholesterol (oxLDL-C), which was accompanied by a marked reduction in CD36 expression in these cells. This result appears to be FXR-independent, as FXR was not detected in the peritoneal macrophages. To assess to what extent FXR modulates atherosclerosis development, FXR/ApoE double-null mice were generated. Female mice were used for atherosclerosis analysis. Compared to ApoE-null mice, the FXR/ApoE double-null mice were found to have less atherosclerotic lesion area in the aorta, despite a further increase in the serum cholesterols and triglycerides. Our results indicate that disruption of the FXR gene could attenuate atherosclerosis development, most likely resulting from reduced oxLDL-C uptake by macrophages. Our study cautions the use of serum lipid levels as a surrogate marker to determine the efficiency of FXR modulators in treating hyperlipidemia.", "title": "Effects of FXR in foam-cell formation and atherosclerosis development." }, { "docid": "11557602", "text": "LXR alpha is a nuclear receptor that has previously been shown to regulate the metabolic conversion of cholesterol to bile acids. Here we define a role for this transcription factor in the control of cellular cholesterol efflux. We demonstrate that retroviral expression of LXR alpha in NIH 3T3 fibroblasts or RAW264.7 macrophages and/or treatment of these cells with oxysterol ligands of LXR results in 7- to 30-fold induction of the mRNA encoding the putative cholesterol/phospholipid transporter ATP-binding cassette (ABC)A1. In contrast, induction of ABCA1 mRNA in response to oxysterols is attenuated in cells that constitutively express dominant-negative forms of LXR alpha or LXR beta that lack the AF2 transcriptional activation domain. We further demonstrate that expression of LXR alpha in NIH 3T3 fibroblasts and/or treatment of these cells with oxysterols is sufficient to stimulate cholesterol efflux to extracellular apolipoprotein AI. The ability of oxysterol ligands of LXR to stimulate efflux is dramatically reduced in Tangier fibroblasts, which carry a loss of function mutation in the ABCA1 gene. Taken together, these results indicate that cellular cholesterol efflux is controlled, at least in part, at the level of transcription by a nuclear receptor-signaling pathway. They suggest a model in which activation of LXRs by oxysterols in response to cellular sterol loading leads to induction of the ABCA1 transporter and the stimulation of lipid efflux to extracellular acceptors. These findings have important implications for our understanding of mammalian cholesterol homeostasis and suggest new opportunities for pharmacological regulation of cellular lipid metabolism.", "title": "Control of cellular cholesterol efflux by the nuclear oxysterol receptor LXR alpha." } ]

[ { "docid": "13794374", "text": "Lipid droplets are ubiquitous triglyceride and sterol ester storage organelles required for energy storage homeostasis and biosynthesis. Although little is known about lipid droplet formation and regulation, it is clear that members of the PAT (perilipin, adipocyte differentiation related protein, tail interacting protein of 47 kDa) protein family coat the droplet surface and mediate interactions with lipases that remobilize the stored lipids. We identified key Drosophila candidate genes for lipid droplet regulation by RNA interference (RNAi) screening with an image segmentation-based optical read-out system, and show that these regulatory functions are conserved in the mouse. Those include the vesicle-mediated Coat Protein Complex I (COPI) transport complex, which is required for limiting lipid storage. We found that COPI components regulate the PAT protein composition at the lipid droplet surface, and promote the association of adipocyte triglyceride lipase (ATGL) with the lipid droplet surface to mediate lipolysis. Two compounds known to inhibit COPI function, Exo1 and Brefeldin A, phenocopy COPI knockdowns. Furthermore, RNAi inhibition of ATGL and simultaneous drug treatment indicate that COPI and ATGL function in the same pathway. These data indicate that the COPI complex is an evolutionarily conserved regulator of lipid homeostasis, and highlight an interaction between vesicle transport systems and lipid droplets.", "title": "COPI Complex Is a Regulator of Lipid Homeostasis" } ]

[ { "docid": "44737533", "text": "METHODS To define potential common features of simian immunodeficiency virus (SIV) infections in different naturally infected host species, we compared the dynamics of viral replication in 31 African green monkeys (10 sabeus, 15 vervets and seven Caribbean AGMs), 14 mandrills and three sooty mangabeys (SMs) that were experimentally infected with their species-specific viruses. \n RESULTS After infection, these SIVs replicated rapidly reaching viral loads (VLs) of 10(5)-10(9) copies/ml of plasma between days 9-14 post-infection (p.i). Set point viremia was established between days 42 and 60 p.i., with levels of approximately 10(5)-10(6) copies/ml in SM and mandrills, and lower levels (10(3)-10(5) copies/ml) in AGMs. VL during the chronic phase did not correlate with viral genome structure: SIVmnd-2 (a vpx-containing virus) and SIVmnd-1 (which does not contain vpu or vpx) replicated to similar levels in mandrills. VL was dependent on virus strain: vervets infected with three different viral strains showed different patterns of viral replication. The pattern of viral replication of SIVagm.sab, which uses both CCR5 and CXCR4 co-receptors was similar to those of the other viruses. \n CONCLUSIONS Our results show a common pattern of SIV replication in naturally and experimentally infected hosts. This is similar overall to that observed in pathogenic SIV infection of macaques. This result indicates that differences in clinical outcome between pathogenic and non-pathogenic infections rely on host responses rather than the characteristics of the virus itself.", "title": "Simian immunodeficiency viruses replication dynamics in African non-human primate hosts: common patterns and species-specific differences." }, { "docid": "25606339", "text": "TLR3 has been implicated in the pathogenesis of several viral infections, including SIV- and HIV-1-induced inflammation and AIDS. However the molecular mechanisms of these TLR3-mediated effects are not known, and it is not known whether HIV interacts with cellular TLR3 to affect disease process. Here we investigate the effects of TLR3 ligands on HIV-1 transactivation using both primary human macrophages and cells containing integrated copies of the HIV-1 promoter. We demonstrate that TLR3 activation induced upregulation of transcription factors such as c-Jun, CCAAT/enhancer-binding protein alpha (CEBPA), signal transducer and activator of transcription (STAT)-1, STAT-2, RELB, and nuclear factor kappa-B1 (NFκB1), most of which are known to regulate the HIV promoter activity. We also demonstrate that TLR3 activation increased HIV-1 transactivation via the c-Jun N-terminal kinase (JNK) and NFκB pathways. This was associated with epigenetic modifications, including decreased histone deacetylase activity, increased histone acetyl transferase (HAT) activity, and increased acetylation of histones H3 and H4 at lysine residues in the nucleosome-0 and nucleosome-1 of the HIV-1 promoter. However, prolonged TLR3 activation decreased HIV-1 transactivation, decreased HAT activity and Tat transcription, and suppressed viral replication. Overall, data suggests that TLR3 can act as viral sensor to mediate viral transactivation, cellular signaling, innate immune response, and inflammation in HIV-infected humans. Our study provides novel insights into the molecular basis for these TLR3-mediated effects.", "title": "Toll-like receptor-3 mediates HIV-1 transactivation via NFκB and JNK pathways and histone acetylation, but prolonged activation suppresses Tat and HIV-1 replication." }, { "docid": "6903077", "text": "In single-stranded ribonucleic acid (RNA) viruses, virus capsid assembly and genome packaging are intertwined processes. Using cryo-electron microscopy and single particle analysis we determined the asymmetric virion structure of bacteriophage MS2, which includes 178 copies of the coat protein, a single copy of the A-protein and the RNA genome. This reveals that in situ, the viral RNA genome can adopt a defined conformation. The RNA forms a branched network of stem-loops that almost all allocate near the capsid inner surface, while predominantly binding to coat protein dimers that are located in one-half of the capsid. This suggests that genomic RNA is highly involved in genome packaging and virion assembly.", "title": "Asymmetric cryo-EM reconstruction of phage MS2 reveals genome structure in situ" }, { "docid": "2758012", "text": "Based on its in vitro unwinding activity on G-quadruplex (G4) DNA, the Bloom syndrome-associated helicase BLM is proposed to participate in telomere replication by aiding fork progression through G-rich telomeric DNA. Single molecule analysis of replicated DNA (SMARD) was used to determine the contribution of BLM helicase to telomere replication. In BLM-deficient cells, replication forks initiating from origins within the telomere, which copy the G-rich strand by leading strand synthesis, moved slower through the telomere compared with the adjacent subtelomere. Fork progression through the telomere was further slowed in the presence of a G4 stabilizer. Using a G4-specific antibody, we found that deficiency of BLM, or another G4-unwinding helicase, the Werner syndrome-associated helicase WRN, resulted in increased G4 structures in cells. Importantly, deficiency of either helicase led to greater increases in G4 DNA detected in the telomere compared with G4 seen genome-wide. Collectively, our findings are consistent with BLM helicase facilitating telomere replication by resolving G4 structures formed during copying of the G-rich strand by leading strand synthesis.", "title": "BLM helicase facilitates telomere replication during leading strand synthesis of telomeres" }, { "docid": "6290112", "text": "Common multi-allelic copy number variants (CNVs) appear enriched for phenotypic associations compared to their biallelic counterparts. Here we investigated the influence of gene dosage effects on adiposity through a CNV association study of gene expression levels in adipose tissue. We identified significant association of a multi-allelic CNV encompassing the salivary amylase gene (AMY1) with body mass index (BMI) and obesity, and we replicated this finding in 6,200 subjects. Increased AMY1 copy number was positively associated with both amylase gene expression (P = 2.31 × 10(-14)) and serum enzyme levels (P < 2.20 × 10(-16)), whereas reduced AMY1 copy number was associated with increased BMI (change in BMI per estimated copy = -0.15 (0.02) kg/m(2); P = 6.93 × 10(-10)) and obesity risk (odds ratio (OR) per estimated copy = 1.19, 95% confidence interval (CI) = 1.13-1.26; P = 1.46 × 10(-10)). The OR value of 1.19 per copy of AMY1 translates into about an eightfold difference in risk of obesity between subjects in the top (copy number > 9) and bottom (copy number < 4) 10% of the copy number distribution. Our study provides a first genetic link between carbohydrate metabolism and BMI and demonstrates the power of integrated genomic approaches beyond genome-wide association studies.", "title": "Low copy number of the salivary amylase gene predisposes to obesity" }, { "docid": "5137019", "text": "HIV-1 replication within macrophages of the CNS often results in cognitive and motor impairment, which is known as HIV-associated dementia (HAD) in its most severe form. IFN-beta suppresses viral replication within these cells during early CNS infection, but the effect is transient. HIV-1 eventually overcomes this protective innate immune response to resume replication through an unknown mechanism, initiating the progression toward HAD. In this article, we show that Suppressor of Cytokine Signaling (SOCS)3, a molecular inhibitor of IFN signaling, may allow HIV-1 to evade innate immunity within the CNS. We found that SOCS3 is elevated in an in vivo SIV/macaque model of HAD and that the pattern of expression correlates with recurrence of viral replication and onset of CNS disease. In vitro, the HIV-1 regulatory protein transactivator of transcription induces SOCS3 in human and murine macrophages in a NF-kappaB-dependent manner. SOCS3 expression attenuates the response of macrophages to IFN-beta at proximal levels of pathway activation and downstream antiviral gene expression and consequently overcomes the inhibitory effect of IFN-beta on HIV-1 replication. These studies indicate that SOCS3 expression, induced by stimuli present in the HIV-1-infected brain, such as transactivator of transcription, inhibits antiviral IFN-beta signaling to enhance HIV-1 replication in macrophages. This consequence of SOCS3 expression in vitro, supported by a correlation with increased viral load and onset of CNS disease in vivo, suggests that SOCS3 may allow HIV-1 to evade the protective innate immune response within the CNS, allowing the recurrence of viral replication and, ultimately, promoting progression toward HAD.", "title": "Suppressor of cytokine signaling 3 inhibits antiviral IFN-beta signaling to enhance HIV-1 replication in macrophages." }, { "docid": "40584205", "text": "We used a mouse nasal model of herpes simplex virus 2 (HSV-2) infection to examine the biological properties of HSV-2 wild-type (wt), TK-negative, and replication-defective strains in vivo. Nasal septa tissue is the major site of wt viral replication post intranasal (i.n.) inoculation. The HSV-2 strain 186 syn(+)-1 wt virus caused lethal encephalitis at doses of 10(4) PFU and above per nostril, and at lower doses no neurons in the trigeminal ganglia were positive for the latency-associated transcript, indicating a lack of latent infection. The 186DeltaKpn TK-negative mutant virus replicated in nasal septa tissue but showed low-level replication in trigeminal ganglia at only one timepoint. In situ hybridization of trigeminal ganglia showed that the number of LAT-positive neurons was proportional to the inoculum dose from 10(3) to 10(6) PFU per nare. The replication-defective mutant virus 5BlacZ showed no replication in nasal septa tissue and no persistence of viral DNA at the inoculation site or the trigeminal ganglia. Nevertheless, inoculation of 5BlacZ or the double-mutant dl5-29 at distal sites reduced acute replication and latent infection of 186DeltaKpn following intranasal challenge. This infection model provides a biological system to test the properties of HSV-2 strains and shows that replication-defective mutant strains do not persist at sites of inoculation or in sensory ganglia but can induce immune protection that reduces the latent viral load of a challenge virus.", "title": "Biological properties of herpes simplex virus 2 replication-defective mutant strains in a murine nasal infection model." }, { "docid": "2638387", "text": "High mutation frequency during reverse transcription has a principal role in the genetic variation of primate lentiviral populations. It is the main driving force for the generation of drug resistance and the escape from immune surveillance. G to A hypermutation is one of the characteristics of primate lentiviruses, as well as other retroviruses, during replication in vivo and in cell culture. The molecular mechanisms of this process, however, remain to be clarified. Here, we demonstrate that CEM15 (also known as apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3G; APOBEC3G), an endogenous inhibitor of human immunodeficiency virus type 1 (HIV-1) replication, is a cytidine deaminase and is able to induce G to A hypermutation in newly synthesized viral DNA. This effect can be counteracted by the HIV-1 virion infectivity factor (Vif). It seems that this viral DNA mutator is a viral defence mechanism in host cells that may induce either lethal hypermutation or instability of the incoming nascent viral reverse transcripts, which could account for the Vif-defective phenotype. Importantly, the accumulation of CEM15-mediated non-lethal hypermutation in the replicating viral genome could potently contribute to the genetic variation of primate lentiviral populations.", "title": "The cytidine deaminase CEM15 induces hypermutation in newly synthesized HIV-1 DNA" }, { "docid": "6820680", "text": "MicroRNAs (miRNAs) are short noncoding RNAs that exert posttranscriptional gene silencing and regulate gene expression. In addition to the hundreds of conserved cellular miRNAs that have been identified, miRNAs of viral origin have been isolated and found to modulate both the viral life cycle and the cellular transcriptome. Thus far, detection of virus-derived miRNAs has been largely limited to DNA viruses, suggesting that RNA viruses may be unable to exploit this aspect of transcriptional regulation. Lack of RNA virus-produced miRNAs has been attributed to the replicative constraints that would incur following RNase III processing of a genomic hairpin. To ascertain whether the generation of viral miRNAs is limited to DNA viruses, we investigated whether influenza virus could be designed to deliver functional miRNAs without affecting replication. Here, we describe a modified influenza A virus that expresses cellular microRNA-124 (miR-124). Insertion of the miR-124 hairpin into an intron of the nuclear export protein transcript resulted in endogenous processing and functional miR-124. We demonstrate that a viral RNA genome incorporating a hairpin does not result in segment instability or miRNA-mediated genomic targeting, thereby permitting the virus to produce a miRNA without having a negative impact on viral replication. This work demonstrates that RNA viruses can produce functional miRNAs and suggests that this level of transcriptional regulation may extend beyond DNA viruses.", "title": "Engineered RNA viral synthesis of microRNAs." }, { "docid": "32720933", "text": "It has recently become clear that several pathogenic DNA viruses express virally encoded microRNAs in infected cells. In particular, numerous microRNAs have been identified in a range of human and animal herpesviruses, and individual microRNAs have also been identified in members of the polyoma- and adenovirus families. Although their functions remain largely unknown, it seems likely that these viral microRNAs play an important role in viral replication in vivo. Here we present an analysis of the microRNAs expressed in human cells during the latent and productive phases of the human papillomavirus genotype 31 (HPV31) replication cycle. Although over 500 cellular microRNAs were cloned and identified, not a single HPV31-specific microRNA was obtained. We therefore concluded that HPV31, and possibly human papillomaviruses in general, does not express viral microRNAs.", "title": "Human papillomavirus genotype 31 does not express detectable microRNA levels during latent or productive virus replication." }, { "docid": "41314611", "text": "Numerous agents attack DNA, forming lesions that impair normal replication. Specialized DNA polymerases transiently replace the replicative polymerase and copy past lesions, thus generating mutations, the major initiating cause of cancer. We monitored, in Escherichia coli, the kinetics of replication of both strands of DNA molecules containing a single replication block in either the leading or lagging strand. Despite a block in the leading strand, lagging-strand synthesis proceeded further, implying transient uncoupling of concurrent strand synthesis. Replication through the lesion requires specialized DNA polymerases and is achieved with similar kinetics and efficiencies in both strands.", "title": "Uncoupling of leading- and lagging-strand DNA replication during lesion bypass in vivo." }, { "docid": "46202852", "text": "Several recent reports indicate that cholesterol might play an important role in human immunodeficiency virus type 1 (HIV-1) replication. We investigated the effects of HIV-1 infection on cholesterol biosynthesis and uptake using microarrays. HIV-1 increased gene expression of cholesterol genes in both transformed T-cell lines and primary CD4(+) T cells. Consistent with our microarray data, (14)C-labeled mevalonate and acetate incorporation was increased in HIV-1-infected cells. Our data also demonstrate that changes in cholesterol biosynthesis and uptake are only observed in the presence of functional Nef, suggesting that increased cholesterol synthesis may contribute to Nef-mediated enhancement of virion infectivity and viral replication.", "title": "Nef induces multiple genes involved in cholesterol synthesis and uptake in human immunodeficiency virus type 1-infected T cells." }, { "docid": "6144969", "text": "Virally induced inflammatory responses, beta cell destruction and release of beta cell autoantigens may lead to autoimmune reactions culminating in type 1 diabetes. Therefore, viral capability to induce beta cell death and the nature of virus-induced immune responses are among key determinants of diabetogenic viruses. We hypothesised that enterovirus infection induces a specific gene expression pattern that results in islet destruction and that such a host response pattern is not shared among all enterovirus infections but varies between virus strains. The changes in global gene expression and secreted cytokine profiles induced by lytic or benign enterovirus infections were studied in primary human pancreatic islet using DNA microarrays and viral strains either isolated at the clinical onset of type 1 diabetes or capable of causing a diabetes-like condition in mice. The expression of pro-inflammatory cytokine genes (IL-1-α, IL-1-β and TNF-α) that also mediate cytokine-induced beta cell dysfunction correlated with the lytic potential of a virus. Temporally increasing gene expression levels of double-stranded RNA recognition receptors, antiviral molecules, cytokines and chemokines were detected for all studied virus strains. Lytic coxsackievirus B5 (CBV-5)-DS infection also downregulated genes involved in glycolysis and insulin secretion. The results suggest a distinct, virus-strain-specific, gene expression pattern leading to pancreatic islet destruction and pro-inflammatory effects after enterovirus infection. However, neither viral replication nor cytotoxic cytokine production alone are sufficient to induce necrotic cell death. More likely the combined effect of these and possibly cellular energy depletion lie behind the enterovirus-induced necrosis of islets.", "title": "Enterovirus-induced gene expression profile is critical for human pancreatic islet destruction" }, { "docid": "20261352", "text": "OBJECTIVE To define the impact of chronic viremia and associated immune activation on B-cell exhaustion in HIV infection. \n DESIGN Progressive HIV infection is marked by B-cell anergy and exhaustion coupled with dramatic hypergammaglobulinemia. Although both upregulation of CD95 and loss of CD21 have been used as markers of infection-associated B-cell dysfunction, little is known regarding the specific profiles of dysfunctional B cells and whether persistent viral replication and its associated immune activation play a central role in driving B-cell dysfunction. \n METHODS Multiparameter flow cytometry was used to define the profile of dysfunctional B cells. The changes in the expression of CD21 and CD95 were tracked on B-cell subpopulations in patients with differential control of viral replication. \n RESULTS : Although the emergence of exhausted, CD21 tissue-like memory B cells followed similar patterns in both progressors and controllers, the frequency of CD21 activated memory B cells was lower in spontaneous controllers. \n CONCLUSION Our results suggest that the loss of CD21 and the upregulation of CD95 occur as separate events during the development of B-cell dysfunction. The loss of CD21 is a marker of B-cell exhaustion induced in the absence of appreciable viral replication, whereas the upregulation of CD95 is tightly linked to persistent viral replication and its associated immune activation. Thus, these dysfunctional profiles potentially represent two functionally distinct states within the B-cell compartment.", "title": "Decoupling activation and exhaustion of B cells in spontaneous controllers of HIV infection." }, { "docid": "7137057", "text": "BACKGROUND & AIMS HBV covalently closed circular DNA (cccDNA), the replicative intermediate responsible for persistent HBV infection of hepatocytes, is the template for transcription of all viral mRNAs. Nuclear cccDNA accumulates as a stable episome organized into minichromosomes by histone and nonhistone proteins. In this study we investigated, by a newly developed sensitive and specific assay, the relationship between viral replication and HBV chromatin assembly, transcription, and interaction with viral and cellular regulatory proteins. \n METHODS To achieve this aim we coupled a quantitative chromatin immunoprecipitation (ChIP) technique to an established method that allows the amplification of virion-encapsidated HBV genomes after transfection of linear HBV DNA into human hepatoma HuH7 cells. The cccDNA-ChIP technique was also applied to study HBV minichromosome transcriptional regulation in liver tissue from HBV-infected patients. \n RESULTS The use of anti-acetyl-H4/-H3 specific antibodies to immunoprecipitate transcriptionally active chromatin revealed that HBV replication is regulated by the acetylation status of the cccDNA-bound H3/H4 histones. Class I histone deacetylases inhibitors induced an evident increase of both cccDNA-bound acetylated H4 and HBV replication. Finally, histones hypoacetylation and histone deacetylase 1 recruitment onto the cccDNA in liver tissue correlated with low HBV viremia in hepatitis B patients. \n CONCLUSIONS We developed a ChIP-based assay to analyze, in vitro and ex vivo, the transcriptional regulation of HBV cccDNA minichromosome. Our results provide new insights on the regulation of HBV replication and identify the enzymatic activities that modulate the acetylation of cccDNA-bound histones as new therapeutic targets for anti-HBV drugs.", "title": "Hepatitis B virus replication is regulated by the acetylation status of hepatitis B virus cccDNA-bound H3 and H4 histones." }, { "docid": "2566674", "text": "The 5′ cap structures of higher eukaryote mRNAs have ribose 2′-O-methylation. Likewise, many viruses that replicate in the cytoplasm of eukaryotes have evolved 2′-O-methyltransferases to autonomously modify their mRNAs. However, a defined biological role for 2′-O-methylation of mRNA remains elusive. Here we show that 2′-O-methylation of viral mRNA was critically involved in subverting the induction of type I interferon. We demonstrate that human and mouse coronavirus mutants lacking 2′-O-methyltransferase activity induced higher expression of type I interferon and were highly sensitive to type I interferon. Notably, the induction of type I interferon by viruses deficient in 2′-O-methyltransferase was dependent on the cytoplasmic RNA sensor Mda5. This link between Mda5-mediated sensing of viral RNA and 2′-O-methylation of mRNA suggests that RNA modifications such as 2′-O-methylation provide a molecular signature for the discrimination of self and non-self mRNA.", "title": "Ribose 2′-O-methylation provides a molecular signature for the distinction of self and non-self mRNA dependent on the RNA sensor Mda5" }, { "docid": "5838067", "text": "MicroRNAs (miRNAs) are expressed in a wide variety of organisms, ranging from plants to animals, and are key posttranscriptional regulators of gene expression. Virally encoded miRNAs are unique in that they could potentially target both viral and host genes. Indeed, we have previously demonstrated that a human cytomegalovirus (HCMV)-encoded miRNA, miR-UL112, downregulates the expression of a host immune gene, MICB. Remarkably, it was shown that the same miRNA also downregulates immediate-early viral genes and that its ectopic expression resulted in reduced viral replication and viral titers. The targets for most of the viral miRNAs, and hence their functions, are still unknown. Here we demonstrate that miR-UL112 also targets the UL114 gene, and we present evidence that the reduction of UL114 by miR-UL112 reduces its activity as uracil DNA glycosylase but only minimally affects virus growth. In addition, we show that two additional HCMV-encoded miRNAs, miR-US25-1 and miR-US25-2, reduce the viral replication and DNA synthesis not only of HCMV but also of other viruses, suggesting that these two miRNAs target cellular genes that are essential for virus growth. Thus, we suggest that in addition to miR-UL112, two additional HCMV miRNAs control the life cycle of the virus.", "title": "Analysis of human cytomegalovirus-encoded microRNA activity during infection." }, { "docid": "24922825", "text": "Traditionally, vaccine development involves tradeoffs between immunogenicity and safety. Live-attenuated vaccines typically offer rapid and durable immunity but have reduced safety when compared to inactivated vaccines. In contrast, the inability of inactivated vaccines to replicate enhances safety at the expense of immunogenicity, often necessitating multiple doses and boosters. To overcome these tradeoffs, we developed the insect-specific alphavirus, Eilat virus (EILV), as a vaccine platform. To address the chikungunya fever (CHIKF) pandemic, we used an EILV cDNA clone to design a chimeric virus containing the chikungunya virus (CHIKV) structural proteins. The recombinant EILV/CHIKV was structurally identical at 10 Å to wild-type CHIKV, as determined by single-particle cryo-electron microscopy, and it mimicked the early stages of CHIKV replication in vertebrate cells from attachment and entry to viral RNA delivery. Yet the recombinant virus remained completely defective for productive replication, providing a high degree of safety. A single dose of EILV/CHIKV produced in mosquito cells elicited rapid (within 4 d) and long-lasting (>290 d) neutralizing antibodies that provided complete protection in two different mouse models. In nonhuman primates, EILV/CHIKV elicited rapid and robust immunity that protected against viremia and telemetrically monitored fever. Our EILV platform represents the first structurally native application of an insect-specific virus in preclinical vaccine development and highlights the potential application of such viruses in vaccinology.", "title": "A chikungunya fever vaccine utilizing an insect-specific virus platform" }, { "docid": "1970884", "text": "Viruses that replicate in the cytoplasm cannot access the host nuclear capping machinery. These viruses have evolved viral methyltransferase(s) to methylate N-7 and 2'-O cap of their RNA; alternatively, they \"snatch\" host mRNA cap to form the 5' end of viral RNA. The function of 2'-O methylation of viral RNA cap is to mimic cellular mRNA and to evade host innate immune restriction. A cytoplasmic virus defective in 2'-O methylation is replicative, but its viral RNA lacks 2'-O methylation and is recognized and eliminated by the host immune response. Such a mutant virus could be rationally designed as a live attenuated vaccine. Here, we use Japanese encephalitis virus (JEV), an important mosquito-borne flavivirus, to prove this novel vaccine concept. We show that JEV methyltransferase is responsible for both N-7 and 2'-O cap methylations as well as evasion of host innate immune response. Recombinant virus completely defective in 2'-O methylation was stable in cell culture after being passaged for >30 days. The mutant virus was attenuated in mice, elicited robust humoral and cellular immune responses, and retained the engineered mutation in vivo. A single dose of immunization induced full protection against lethal challenge with JEV strains in mice. Mechanistically, the attenuation phenotype was attributed to the enhanced sensitivity of the mutant virus to the antiviral effects of interferon and IFIT proteins. Collectively, the results demonstrate the feasibility of using 2'-O methylation-defective virus as a vaccine approach; this vaccine approach should be applicable to other flaviviruses and nonflaviviruses that encode their own viral 2'-O methyltransferases.", "title": "Rational design of a flavivirus vaccine by abolishing viral RNA 2'-O methylation." }, { "docid": "17077004", "text": "OBJECTIVES To explore the association between a stable partnership and clinical outcome in HIV infected patients receiving highly active antiretroviral therapy (HAART). \n DESIGN Prospective cohort study of adults with HIV (Swiss HIV cohort study). \n SETTING Seven outpatient clinics throughout Switzerland. \n PARTICIPANTS The 3736 patients in the cohort who started HAART before 2002 (median age 36 years, 29% female, median follow up 3.6 years). \n MAIN OUTCOME MEASURES Time to AIDS or death (primary endpoint), death alone, increases in CD4 cell count of at least 50 and 100 above baseline, optimal viral suppression (a viral load below 400 copies/ml), and viral rebound. \n RESULTS During follow up 2985 (80%) participants reported a stable partnership on at least one occasion. When starting HAART, 52% (545/1042) of participants reported a stable partnership; after five years of follow up 46% (190/412) of participants reported a stable partnership. In an analysis stratified by previous antiretroviral therapy and clinical stage when starting HAART (US Centers for Disease Control and Prevention group A, B, or C), the adjusted hazard ratio for progression to AIDS or death was 0.79 (95% confidence interval 0.63 to 0.98) for participants with a stable partnership compared with those without. Adjusted hazards ratios for other endpoints were 0.59 (0.44 to 0.79) for progression to death, 1.15 (1.06 to 1.24) for an increase in CD4 cells of 100 counts/microl or more, and 1.06 (0.98 to 1.14) for optimal viral suppression. \n CONCLUSIONS A stable partnership is associated with a slower rate of progression to AIDS or death in HIV infected patients receiving HAART.", "title": "Stable partnership and progression to AIDS or death in HIV infected patients receiving highly active antiretroviral therapy: Swiss HIV cohort study." } ]

[ { "docid": "13625993", "text": "OBJECTIVE To determine the effectiveness and cost effectiveness of using information from circulating biomarkers to inform the prioritisation process of patients with stable angina awaiting coronary artery bypass graft surgery. \n DESIGN Decision analytical model comparing four prioritisation strategies without biomarkers (no formal prioritisation, two urgency scores, and a risk score) and three strategies based on a risk score using biomarkers: a routinely assessed biomarker (estimated glomerular filtration rate), a novel biomarker (C reactive protein), or both. The order in which to perform coronary artery bypass grafting in a cohort of patients was determined by each prioritisation strategy, and mean lifetime costs and quality adjusted life years (QALYs) were compared. \n DATA SOURCES Swedish Coronary Angiography and Angioplasty Registry (9935 patients with stable angina awaiting coronary artery bypass grafting and then followed up for cardiovascular events after the procedure for 3.8 years), and meta-analyses of prognostic effects (relative risks) of biomarkers. \n RESULTS The observed risk of cardiovascular events while on the waiting list for coronary artery bypass grafting was 3 per 10,000 patients per day within the first 90 days (184 events in 9935 patients). Using a cost effectiveness threshold of pound20,000- pound30,000 (euro22,000-euro33,000; $32,000-$48,000) per additional QALY, a prioritisation strategy using a risk score with estimated glomerular filtration rate was the most cost effective strategy (cost per additional QALY was < pound410 compared with the Ontario urgency score). The impact on population health of implementing this strategy was 800 QALYs per 100,000 patients at an additional cost of pound 245,000 to the National Health Service. The prioritisation strategy using a risk score with C reactive protein was associated with lower QALYs and higher costs compared with a risk score using estimated glomerular filtration rate. \n CONCLUSION Evaluating the cost effectiveness of prognostic biomarkers is important even when effects at an individual level are small. Formal prioritisation of patients awaiting coronary artery bypass grafting using a routinely assessed biomarker (estimated glomerular filtration rate) along with simple, routinely collected clinical information was cost effective. Prioritisation strategies based on the prognostic information conferred by C reactive protein, which is not currently measured in this context, or a combination of C reactive protein and estimated glomerular filtration rate, is unlikely to be cost effective. The widespread practice of using only implicit or informal means of clinically ordering the waiting list may be harmful and should be replaced with formal prioritisation approaches.", "title": "Assessing the cost effectiveness of using prognostic biomarkers with decision models: case study in prioritising patients waiting for coronary artery surgery" } ]

[ { "docid": "27054878", "text": "BACKGROUND Preoperative C-reactive protein (CRP) levels more than 10 mg/l have been shown to be associated with increased morbidity and mortality after cardiac surgery. We examine the value of preoperative CRP levels less than 10 mg/l for predicting long-term, all-cause mortality and hospital length of stay in surgical patients undergoing primary, nonemergent coronary artery bypass graft-only surgery. \n METHODS We examined the association between preoperative CRP levels stratified into four categories (< 1, 1-3, 3-10, and > 10 mg/l), and 7-yr all-cause mortality and hospital length of stay in 914 prospectively enrolled primary, nonemergent coronary artery bypass graft-only surgical patients using a proportional hazards regression model. \n RESULTS Eighty-seven patients (9.5%) died during a mean follow-up period of 4.8 +/- 1.5 yr. After proportional hazards adjustment, the 3-10 and > 10 mg/l preoperative CRP groups were associated with long-term, all-cause mortality (hazards ratios [95% CI]: 2.50 [1.22-5.16], P = 0.01 and 2.66 [1.21-5.80], P = 0.02, respectively) and extended hospital length of stay (1.32 [1.07-1.63], P < 0.001 and 1.27 [1.02-1.62], P = 0.001, respectively). \n CONCLUSION We demonstrate that preoperative CRP levels as low as 3 mg/l are associated with increased long-term mortality and extended hospital length of stay in relatively lower-acuity patients undergoing primary, nonemergent coronary artery bypass graft-only surgery. These important findings may allow for more objective risk stratification of patients who present for uncomplicated surgical coronary revascularization.", "title": "Preoperative C-reactive protein predicts long-term mortality and hospital length of stay after primary, nonemergent coronary artery bypass grafting." }, { "docid": "750781", "text": "BACKGROUND Few studies have compared long-term status of bypass grafts between patients with and without diabetes, and uncertainty exists as to whether diabetes independently predicts poor clinical outcome after CABG. \n METHODS AND RESULTS Among 1526 patients in BARI who underwent CABG as initial revascularization, 99 of 292 (34%) with treated diabetes mellitus (TDM) (those on insulin or oral hypoglycemic agents) and 469 of 1234 (38%) without TDM had follow-up angiography. Angiograms with the longest interval from initial surgery and before any percutaneous graft intervention (mean 3.9 years) were reviewed. An average of 3.0 grafts were placed at initial CABG for patients with TDM (n=297; internal mammary artery [IMA], 33%) and 2.9 grafts for patients without TDM (n=1347; IMA, 34%). Patients with TDM were more likely than those without to have small (<1.5 mm) grafted distal vessels (29% versus 22%) and vessels of poor quality (9% versus 6%). On follow-up angiography, 89% of IMA grafts were free of stenoses > or =50% among patients with TDM versus 85% among patients without TDM (P=0.23). For vein grafts, the corresponding percentages were 71% versus 75% (P=0.40). After statistical adjustment, TDM was unrelated to having a graft stenosis > or =50% (adjusted odds ratio, 0.87; 95% CI, 0.58 to 1.32). \n CONCLUSIONS Despite diabetic patients' having smaller distal vessels and vessels judged to be of poorer quality, diabetes does not appear to adversely affect patency of IMA or vein grafts over an average of 4-year follow-up. Previously observed differences in survival between CABG-treated patients with and without diabetes may be largely a result of differential risk of mortality from noncardiac causes.", "title": "Coronary bypass graft patency in patients with diabetes in the Bypass Angioplasty Revascularization Investigation (BARI)." }, { "docid": "9846940", "text": "OBJECTIVE To determine if preoperative statin treatment is associated with a reduction in systemic inflammatory response (SIR) and myocardial damage markers following cardiac surgery with cardiopulmonary bypass (CPB). \n METHODS We study a prospective cohort of 138 patients who underwent coronary and valvular surgery with CPB. We differentiate two study groups: patients with (group A, n=72) or without (group B, n=66) statins. Plasma levels of pro-inflammatory interleukins (tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, IL-8 and IL-2R), creatine phosphokinase (CPK), CPK-MB and troponin I were measured before and 1, 6, 24 and >72 h after surgery. \n RESULTS The baseline, operative and postoperative morbidity and mortality characteristics were similar for both the groups. Group A had significantly lower postoperative levels of IL-6 than group B at 6h (68.8+/-5 pg ml(-1) vs 108.9+/-108 pg ml(-1), p=0.01), 24h (71.7+/-7 pg ml(-1) vs 110.4+/-106 pg ml(-1), p=0.01) and before hospital discharge (21.6+/-12 pg ml(-1) vs 32.8+/-27 pg ml(-1), p=0.005), as well as significantly lower average IL-6 levels in the first 24h following surgery (71.8+/-5 pgml(-1) vs 112.8+/-82 pg ml(-1), p=0.002). The postoperative CPK-MB at 24h (19.7+/-23 ng ml(-1) vs 33.1+/-32 ng ml(-1), p=0.02) and troponin I levels at the end of the intervention (2.2+/-2.2 ng ml(-1) vs 3.3+/-3.1 ng ml(-1), p=0.03) and at 24h (4.1+/-3.5 ng ml(-1) vs 6.6+/-8 ng ml(-1), p=0.04) were also significantly lower in the group treated with statins prior to surgery. \n CONCLUSIONS Preoperative treatment with statins is associated with a lower biochemical parameters of SIR and myocardial damage following cardiac surgery with CPB, regardless of it being coronary bypass grafting (CABG) or valvular surgery.", "title": "Preoperative statin treatment reduces systemic inflammatory response and myocardial damage in cardiac surgery." }, { "docid": "40156901", "text": "BACKGROUND Acute kidney injury (AKI) after cardiac surgery is associated with increased morbidity and mortality. \n METHODS We assessed whether statin treatment is associated with a lower incidence of postoperative AKI in 2,104 consecutive patients who underwent coronary artery bypass graft or valve surgery at the Minneapolis Veterans Administration Medical Center. Acute kidney injury was defined as absolute increase greater than 0.3 mg/dL or relative increase greater than 50% in serum creatinine from baseline, within 48 hours after surgery or requiring postoperative hemodialysis per AKI network. Propensity scores were utilized to adjust for the differences between the statin and the no-statin treatment groups. All statins were converted to equivalent-dose simvastatin and divided at the median to construct high-dose (≥40 mg) and low-dose (<40 mg) statin groups. \n RESULTS Of the 2,104 patients, 1,435 (68%) were taking statins (638 high-dose) and 495 (24%) developed AKI (25% high-dose vs 40% low-dose vs 35% no-statin; p = 0.014). Estimated preoperative glomerular filtration rate (p = 0.003), diabetes mellitus (p=0.02), valve surgery with or without coronary artery bypass graft (p = 0.024), cardiopulmonary bypass time (p = 0.001), and intraaortic balloon pump (p = 0.055) were independent predictors of AKI. After propensity adjustment statin treatment was not associated with postoperative AKI (odds ratio 0.79; 95% confidence interval 0.59 to 1.06; p = 0.11 for high-dose v. no-statin). After full adjustment for all independent predictors of AKI, the results did not change. Statins also had no effect on the incidence of postoperative hemodialysis (0.8% high-dose vs 1.9% low-dose vs 1% no-statin; p = 0.15). \n CONCLUSIONS Statin treatment is not associated with a lower incidence of AKI after cardiac surgery.", "title": "Dose-dependent effect of statins on the incidence of acute kidney injury after cardiac surgery." }, { "docid": "20887554", "text": "BACKGROUND C-reactive protein (CRP) is a known risk factor for cardiovascular events in the healthy population and in patients with coronary artery disease. High CRP levels before cardiac surgery are associated with worse short-term outcome, but its role after discharge home remains unknown. The study objective was to evaluate the effect of CRP on short-term and mid-term outcome after cardiac surgery. \n METHODS From August 2000 to May 2004, values for preoperative CRP were available for 597 unselected patients undergoing cardiac operations. CRP was used to divide this cohort in two groups: a low inflammatory status (LHS) group of 354 patients with CRP of less than 0.5 mg/dL, and a high inflammatory status (HIS) group of 243 patients with a CRP of 0.5 mg/dL or more. Follow-up lasted a maximum of 3 years (median, 1.8 +/- 1.5 years) and was 92.6% complete. \n RESULTS In-hospital mortality was 8.2% in the HIS group and 3.4% in the LIS group (odds ratio [OR], 2.61; p = 0.02). Incidence of postoperative infections was 16.5% in the HIS group and 5.1% in the LIS group (OR, 3.25; p = 0.0001). Sternal wound infections were also more frequent in the HIS group (10.7% versus 2.8%; OR, 3.43; p = 0.002). During follow-up, the HIS group had worse survival (88.5% +/- 2.9% versus 91.9% +/- 2.5%; OR, 1.93; p = 0.05) and a higher need of hospitalization for cardiac-related causes (73.6% +/- 6% versus 86.5% +/- 3.2%; OR, 1.82; p = 0.05). \n CONCLUSIONS Patients undergoing cardiac surgery with a CRP level of 0.5 mg/dL or more are exposed to a higher risk of in-hospital mortality and postoperative infections. Despite surgical correction of cardiac disease, a high preoperative CRP value is an independent risk factor for mid-term survival and hospitalization for cardiac causes.", "title": "Preoperative C-reactive protein predicts mid-term outcome after cardiac surgery." }, { "docid": "7813993", "text": "Coronary heart disease (CHD) patients often show atherosclerotic vascular disease in other vascular territories. We evaluated how often whole-body MR imaging detects concomitant arterial pathologies in CHD patients, and how often these pathologies were not known to the patients previously. Of 4,814 participants in the population-based Heinz Nixdorf Recall Study, 327 reported CHD (i.e., previous coronary bypass surgery, angioplasty); of those, 160 patients (mean age 66.4 years) were examined using MR of the brain, the heart (excluding the coronary arteries), and whole-body MR angiography. The prevalence of each vascular pathology was assessed, correlated to the others and compared to patients’ histories. Of the 160 CHD patients, 16 (10%) showed MR signs of stroke, and 77 (48.1%) had a stenosis >50% in at least one extracerebral peripheral artery (other than the coronaries), including 28 (17.5%) with relevant renal artery stenoses, and 20 (12.5%) with relevant extracerebral internal carotid artery stenoses. False negative histories were reported in 12 of 81 cases with myocardial infarctions, and in 11 of 16 cases with cerebrovascular infarctions. This whole-body atherosclerosis MR screening program allows previously unknown concomitant vascular disease to be detected in coronary heart disease patients. Its prospective value should be assessed in further studies.", "title": "Whole-body MR vascular screening detects unsuspected concomitant vascular disease in coronary heart disease patients" }, { "docid": "5884524", "text": "BACKGROUND Although unstable coronary artery disease is the most common reason for admission to a coronary care unit, the long-term prognosis of patients with this diagnosis is unknown. This is particularly true for patients with diabetes mellitus, who are known to have a high morbidity and mortality after an acute myocardial infarction. \n METHODS AND RESULTS Prospectively collected data from 6 different countries in the Organization to Assess Strategies for Ischemic Syndromes (OASIS) registry were analyzed to determine the 2-year prognosis of diabetic and nondiabetic patients who were hospitalized with unstable angina or non-Q-wave myocardial infarction. Overall, 1718 of 8013 registry patients (21%) had diabetes. Diabetic patients had a higher rate of coronary bypass surgery than nondiabetic patients (23% versus 20%, P:<0.001) but had similar rates of catheterization and angioplasty. Diabetes independently predicted mortality (relative risk [RR], 1.57; 95% CI, 1.38 to 1.81; P:<0.001), as well as cardiovascular death, new myocardial infarction, stroke, and new congestive heart failure. Moreover, compared with their nondiabetic counterparts, women had a significantly higher risk than men (RR, 1.98; 95% CI, 1.60 to 2.44; and RR, 1.28; 95% CI, 1.06 to 1.56, respectively). Interestingly, diabetic patients without prior cardiovascular disease had the same event rates for all outcomes as nondiabetic patients with previous vascular disease. \n CONCLUSIONS Hospitalization for unstable angina or non-Q-wave myocardial infarction predicts a high 2-year morbidity and mortality; this is especially evident for patients with diabetes. Diabetic patients with no previous cardiovascular disease have the same long-term morbidity and mortality as nondiabetic patients with established cardiovascular disease after hospitalization for unstable coronary artery disease.", "title": "Impact of diabetes on long-term prognosis in patients with unstable angina and non-Q-wave myocardial infarction: results of the OASIS (Organization to Assess Strategies for Ischemic Syndromes) Registry." }, { "docid": "20130904", "text": "BACKGROUND Gastric bypass patients with a range of disturbed eating patterns before surgery may be at risk of returning to old patterns postoperatively. Recent research has shown that binge eating is common among the obese before surgery as well as in the postoperative maintenance phase and appears to be linked to poorer outcome. Although \"grazing\" behavior has not been specifically studied, it is also a high-risk pattern. This paper is a descriptive investigation summarizing postoperative eating patterns in a group of patients. \n METHODS Patients completed self-report questionnaires before surgery and were seen for a preoperative mental health evaluation with particular focus on assessing eating patterns. Patients with high-risk eating patterns, both binge eating and \"grazing\", were identified, invited to attend a post-surgery therapy group, and were given additional follow-up questionnaires regarding postoperative eating patterns. \n RESULTS Consistent with recent studies, many high-risk patients reported recurrent loss of control over eating and, in some cases, subsequent weight gain. Although no longer able to eat large amounts, \"grazing\" became a more common pattern, appearing >or=6 months following surgery. \n CONCLUSION Different forms of overeating need to be assessed in this population, focusing on the subjective loss of control rather than on the quantity consumed. Although many patients do not meet strict criteria for binge eating disorder before surgery, these \"grazers\" are also high-risk. Former binge eaters often turn into \"grazers\" following surgery. Interventions are needed for at-risk patients.", "title": "\"Grazing\": a high-risk behavior." }, { "docid": "36288526", "text": "OBJECTIVE The effects of hydroxyethyl starch on bleeding after cardiopulmonary bypass were determined. \n METHODS A meta-analysis was performed of postoperative blood loss in randomized clinical trials of hydroxyethyl starch versus albumin for fluid management in adult cardiopulmonary bypass surgery. Impacts of hydroxyethyl starch molecular weight and molar substitution were assessed. Randomized trials directly comparing different hydroxyethyl starch solutions were also included. \n RESULTS Eighteen trials with 970 total patients were included. Compared with albumin, hydroxyethyl starch increased postoperative blood loss by 33.3% of a pooled SD (95% confidence interval, 18.2%-48.3%; P < .001). Risk of reoperation for bleeding was more than doubled by hydroxyethyl starch (relative risk, 2.24; 95% confidence interval, 1.14-4.40; P = .020). Hydroxyethyl starch increased transfusion of red blood cells by 28.4% of a pooled SD (95% confidence interval, 12.2%-44.6%; P < .001), of fresh-frozen plasma by 30.6% (95% confidence interval, 8.0%-53.1%; P = .008), and of platelets by 29.8% (95% confidence interval, 3.4%-56.2%; P = .027). None of these effects differed significantly between hydroxyethyl starch 450/0.7 and 200/0.5. Insufficient data were available for hydroxyethyl starch 130/0.4 versus albumin; however, no significant differences were detected in head-to-head comparisons of hydroxyethyl starch 130/0.4 with 200/0.5. Albumin improved hemodynamics. There were no differences in fluid balance, ventilator time, intensive care unit stay, or mortality. \n CONCLUSIONS Hydroxyethyl starch increased blood loss, reoperation for bleeding, and blood product transfusion after cardiopulmonary bypass. There was no evidence that these risks could be mitigated by lower molecular weight and substitution.", "title": "Effect of hydroxyethyl starch on bleeding after cardiopulmonary bypass: a meta-analysis of randomized trials." }, { "docid": "5824985", "text": "BACKGROUND Bariatric surgery is becoming a more widespread treatment for obesity. Comprehensive evidence of the long-term effects of contemporary surgery on a broad range of clinical outcomes in large populations treated in routine clinical practice is lacking. The objective of this study was to measure the association between bariatric surgery, weight, body mass index, and obesity-related co-morbidities. \n METHODS AND FINDINGS This was an observational retrospective cohort study using data from the United Kingdom Clinical Practice Research Datalink. All 3,882 patients registered in the database and with bariatric surgery on or before 31 December 2014 were included and matched by propensity score to 3,882 obese patients without surgery. The main outcome measures were change in weight and body mass index over 4 y; incident diagnoses of type 2 diabetes mellitus (T2DM), hypertension, angina, myocardial infarction (MI), stroke, fractures, obstructive sleep apnoea, and cancer; mortality; and resolution of hypertension and T2DM. Weight measures were available for 3,847 patients between 1 and 4 mo, 2,884 patients between 5 and 12 mo, and 2,258 patients between 13 and 48 mo post-procedure. Bariatric surgery patients exhibited rapid weight loss for the first four postoperative months, at a rate of 4.98 kg/mo (95% CI 4.88-5.08). Slower weight loss was sustained to the end of 4 y. Gastric bypass (6.56 kg/mo) and sleeve gastrectomy (6.29 kg/mo) were associated with greater initial weight reduction than gastric banding (2.77 kg/mo). Protective hazard ratios (HRs) were detected for bariatric surgery for incident T2DM, 0.68 (95% CI 0.55-0.83); hypertension, 0.35 (95% CI 0.27-0.45); angina, 0.59 (95% CI 0.40-0.87);MI, 0.28 (95% CI 0.10-0.74); and obstructive sleep apnoea, 0.55 (95% CI 0.40-0.87). Strong associations were found between bariatric surgery and the resolution of T2DM, with a HR of 9.29 (95% CI 6.84-12.62), and between bariatric surgery and the resolution of hypertension, with a HR of 5.64 (95% CI 2.65-11.99). No association was detected between bariatric surgery and fractures, cancer, or stroke. Effect estimates for mortality found no protective association with bariatric surgery overall, with a HR of 0.97 (95% CI 0.66-1.43). The data used were recorded for the management of patients in primary care and may be subject to inaccuracy, which would tend to lead to underestimates of true relative effect sizes. \n CONCLUSIONS Bariatric surgery as delivered in the UK healthcare system is associated with dramatic weight loss, sustained at least 4 y after surgery. This weight loss is accompanied by substantial improvements in pre-existing T2DM and hypertension, as well as a reduced risk of incident T2DM, hypertension, angina, MI, and obstructive sleep apnoea. Widening the availability of bariatric surgery could lead to substantial health benefits for many people who are morbidly obese.", "title": "Bariatric Surgery in the United Kingdom: A Cohort Study of Weight Loss and Clinical Outcomes in Routine Clinical Care." }, { "docid": "18872233", "text": "IMPORTANCE Bariatric surgery is associated with sustained weight loss and improved physical health status for severely obese individuals. Mental health conditions may be common among patients seeking bariatric surgery; however, the prevalence of these conditions and whether they are associated with postoperative outcomes remains unknown. \n OBJECTIVE To determine the prevalence of mental health conditions among bariatric surgery candidates and recipients, to evaluate the association between preoperative mental health conditions and health outcomes following bariatric surgery, and to evaluate the association between surgery and the clinical course of mental health conditions. \n DATA SOURCES We searched PubMed, MEDLINE on OVID, and PsycINFO for studies published between January 1988 and November 2015. Study quality was assessed using an adapted tool for risk of bias; quality of evidence was rated based on GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. \n FINDINGS We identified 68 publications meeting inclusion criteria: 59 reporting the prevalence of preoperative mental health conditions (65,363 patients) and 27 reporting associations between preoperative mental health conditions and postoperative outcomes (50,182 patients). Among patients seeking and undergoing bariatric surgery, the most common mental health conditions, based on random-effects estimates of prevalence, were depression (19% [95% CI, 14%-25%]) and binge eating disorder (17% [95% CI, 13%-21%]). There was conflicting evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Neither depression nor binge eating disorder was consistently associated with differences in weight outcomes. Bariatric surgery was, however, consistently associated with postoperative decreases in the prevalence of depression (7 studies; 8%-74% decrease) and the severity of depressive symptoms (6 studies; 40%-70% decrease). \n CONCLUSIONS AND RELEVANCE Mental health conditions are common among bariatric surgery patients-in particular, depression and binge eating disorder. There is inconsistent evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Moderate-quality evidence supports an association between bariatric surgery and lower rates of depression postoperatively.", "title": "Mental Health Conditions Among Patients Seeking and Undergoing Bariatric Surgery: A Meta-analysis." }, { "docid": "12991445", "text": "OBJECTIVE To determine the effects of smoking, plasma lipids, lipoproteins, apolipoproteins, and fibrinogen on the patency of saphenous vein femoropopliteal bypass grafts at one year. \n DESIGN Prospective study of patients with saphenous vein femoropopliteal bypass grafts entered into a multicentre trial. \n SETTING Surgical wards, outpatient clinics, and home visits coordinated by two tertiary referral centres in London and Birmingham. \n PATIENTS 157 Patients (mean age 66.6 (SD 8.2) years), 113 with patent grafts and 44 with occluded grafts one year after bypass. \n MAIN OUTCOME MEASURE Cumulative percentage patency at one year. \n RESULTS Markers for smoking (blood carboxyhaemoglobin concentration (p less than 0.05) and plasma thiocyanate concentration (p less than 0.01) and plasma concentrations of fibrinogen (p less than 0.001) and apolipoproteins AI (p less than 0.04) and (a) (p less than 0.05) were significantly higher in patients with occluded grafts. Serum cholesterol concentrations were significantly higher in patients with grafts that remained patent one year after bypass (p less than 0.005). Analysis of the smoking markers indicated that a quarter of patients (40) were untruthful in their claims to have stopped smoking. Based on smoking markers, patency of grafts in smokers was significantly lower at one year by life table analysis than in non-smokers (63% v 84%, p less than 0.02). Patency was significantly higher by life table analysis in patients with a plasma fibrinogen concentration below the median than in those with a concentration above (90% v 57%, p less than 0.0002). Surprisingly, increased plasma low density lipoprotein cholesterol concentration was significantly associated with improved patency at one year (85%) at values above the median compared with patency (only 68%) at values in the lower half of the range (p less than 0.02). \n CONCLUSIONS Plasma fibrinogen concentration was the most important variable predicting graft occlusion, followed by smoking markers. A more forceful approach is needed to stop patients smoking; therapeutic measures to improve patency of vein grafts should focus on decreasing plasma fibrinogen concentration rather than serum cholesterol concentration.", "title": "Influence of smoking and plasma factors on patency of femoropopliteal vein grafts." }, { "docid": "25028913", "text": "BACKGROUND In patients with unstable coronary artery disease, there is a relation between the short-term risk of death and blood levels of troponin T (a marker of myocardial damage) and C-reactive protein and fibrinogen (markers of inflammation). Using information obtained during an extension of the follow-up period in the Fragmin during Instability in Coronary Artery Disease trial, we evaluated the usefulness of troponin T, C-reactive protein, and fibrinogen levels and other indicators of risk as predictors of the long-term risk of death from cardiac causes. \n METHODS Levels of C-reactive protein and fibrinogen at enrollment and the maximal level of troponin T during the first 24 hours after enrollment were analyzed in 917 patients included in a clinical trial of low-molecular-weight heparin in unstable coronary artery disease. The patients were followed for a mean of 37.0 months (range, 1.6 to 50.6). \n RESULTS During follow-up, 1.2 percent of the 173 patients with maximal blood troponin T levels of less than 0.06 microg per liter died of cardiac causes, as compared with 8.7 percent of the 367 patients with levels of 0.06 to 0.59 microg per liter and 15.4 percent of the 377 patients with levels of at least 0.60 microg per liter (P=0.007 and P=0.001, respectively). The rates of death from cardiac causes were 5.7 percent among the 314 patients with blood C-reactive protein levels of less than 2 mg per liter, 7.8 percent among the 294 with levels of 2 to 10 mg per liter, and 16.5 percent among the 309 with levels of more than 10 mg per liter (P=0.29 and P=0.001, respectively). The rates of death from cardiac causes were 5.4 percent among the 314 patients with blood fibrinogen levels of less than 3.4 g per liter, 12.0 percent among the 300 with levels of 3.4 to 3.9 g per liter, and 12.9 percent among the 303 with levels of at least 4.0 g per liter (P=0.004 and P=0.69, respectively). In a multivariate analysis, levels of troponin T and C-reactive protein were independent predictors of the risk of death from cardiac causes. \n CONCLUSIONS In unstable coronary artery disease, elevated levels of troponin T and C-reactive protein are strongly related to the long-term risk of death from cardiac causes. These markers are independent risk factors, and their effects are additive with respect to each other and other clinical indicators of risk.", "title": "Markers of myocardial damage and inflammation in relation to long-term mortality in unstable coronary artery disease. FRISC Study Group. Fragmin during Instability in Coronary Artery Disease." }, { "docid": "11933721", "text": "UNLABELLED Biomechanical studies suggest a suture bridge technique enhances rotator cuff tendon footprint contact area, holding strength, and mean contact pressure. Based on these studies, we asked whether (1) the suture bridge technique would provide a high rate of cuff integrity after surgery, (2) the status of the repaired cuff would change with time, (3) preoperative factors could predict postoperative cuff integrity, and (4) patients with retears had less favorable pain, functional scores, range of motion (ROM), and muscle strength compared with those with intact repairs. We prospectively followed 78 patients with arthroscopic repairs in whom we used the suture bridge technique. The integrity of the rotator cuff repair was determined using ultrasonographic evaluation at 4.5 and 12 months after surgery. Ultrasonography revealed intact cuffs in 91% at 4.5 months postoperatively, all of which were maintained at the 12-month followup. Failure rates were 17.6% (three of 17) for massive tears, 11.1% (two of 18) for large tears, 6.3% (two of 32) for medium tears, and no failures for small tears. Preoperative fatty degeneration of the supraspinatus muscle was a strong predictor of cuff integrity. We found no correlation between the integrity and clinical outcomes except for a temporary decrease of abduction strength at 6 months. Arthroscopic repair using suture bridge technique can achieve a low retear rate in shoulders treated for rotator cuff tears, but the occurrence of retear did not influence the outcome. LEVEL OF EVIDENCE Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.", "title": "Does an arthroscopic suture bridge technique maintain repair integrity?: a serial evaluation by ultrasonography." }, { "docid": "24088502", "text": "CONTEXT A number of countries have implemented a policy of universal leukoreduction of their blood supply, but the potential role of leukoreduction in decreasing postoperative mortality and infection is unclear. \n OBJECTIVE To evaluate clinical outcomes following adoption of a national universal prestorage leukoreduction program for blood transfusions. \n DESIGN, SETTING, AND POPULATION Retrospective before-and-after cohort study conducted from August 1998 to August 2000 in 23 academic and community hospitals throughout Canada, enrolling 14 786 patients who received red blood cell transfusions following cardiac surgery or repair of hip fracture, or who required intensive care following a surgical intervention or multiple trauma. \n INTERVENTION Universal prestorage leukoreduction program introduced by 2 Canadian blood agencies. A total of 6982 patients were enrolled during the control period and 7804 patients were enrolled following prestorage leukoreduction. \n MAIN OUTCOME MEASURES All-cause in-hospital mortality and serious nosocomial infections (pneumonia, bacteremia, septic shock, all surgical site infections) occurring after first transfusion and at least 2 days after index procedure or intensive care unit admission. Secondary outcomes included rates of posttransfusion fever and antibiotic use. \n RESULTS Unadjusted in-hospital mortality rates were significantly lower following the introduction of leukoreduction compared with the control period (6.19% vs 7.03%, respectively; P =.04). Compared with the control period, the adjusted odds of death following leukoreduction were reduced (odds ratio [OR], 0.87; 95% confidence interval [CI], 0.75-0.99), but serious nosocomial infections did not decrease (adjusted OR, 0.97; 95% CI, 0.87-1.09). The frequency of posttransfusion fevers decreased significantly following leukoreduction (adjusted OR, 0.86; 95% CI, 0.79-0.94), as did antibiotic use (adjusted OR, 0.90; 95% CI, 0.82-0.99). \n CONCLUSION A national universal leukoreduction program is potentially associated with decreased mortality as well as decreased fever episodes and antibiotic use after red blood cell transfusion in high-risk patients.", "title": "Clinical outcomes following institution of the Canadian universal leukoreduction program for red blood cell transfusions." }, { "docid": "72933407", "text": "ContextSeveral novel risk factors for atherosclerosis have recently been proposed, but few comparative data exist to guide clinical use of these emerging biomarkers. ObjectiveTo compare the predictive value of 11 lipid and nonlipid biomarkers as risk factors for development of symptomatic peripheral arterial disease (PAD).Design, Setting, and ParticipantsNested case-control study using plasma samples collected at baseline from a prospective cohort of 14 916 initially healthy US male physicians aged 40 to 84 years, of whom 140 subsequently developed symptomatic PAD (cases); 140 age- and smoking status–matched men who remained free of vascular disease during an average 9-year follow-up period were randomly selected as controls. Main Outcome MeasureIncident PAD, as determined by baseline total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol–HDL-C ratio, triglycerides, homocysteine, C-reactive protein (CRP), lipoprotein(a), fibrinogen, and apolipoproteins (apo) A-I and B-100.ResultsIn univariate analyses, plasma levels of total cholesterol (P<.001), LDL-C (P = .001), triglycerides (P = .001), apo B-100 (P = .001), fibrinogen (P = .02), CRP (P = .006), and the total cholesterol–HDL-C ratio (P<.001) were all significantly higher at baseline among men who subsequently developed PAD compared with those who did not, while levels of HDL-C (P = .009) and apo A-I (P = .05) were lower. Nonsignificant baseline elevations of lipoprotein(a) (P = .40) and homocysteine (P = .90) were observed. In multivariable analyses, the total cholesterol–HDL-C ratio was the strongest lipid predictor of risk (relative risk [RR] for those in the highest vs lowest quartile, 3.9; 95% confidence interval [CI], 1.7-8.6), while CRP was the strongest nonlipid predictor (RR for the highest vs lowest quartile, 2.8; 95% CI, 1.3-5.9). In assessing joint effects, addition of CRP to standard lipid screening significantly improved risk prediction models based on lipid screening alone (P<.001).ConclusionsOf 11 atherothrombotic biomarkers assessed at baseline, the total cholesterol–HDL-C ratio and CRP were the strongest independent predictors of development of peripheral arterial disease. C-reactive protein provided additive prognostic information over standard lipid measures.", "title": "Novel Risk Factors for Systemic Atherosclerosis: A Comparison of C-Reactive Protein, Fibrinogen, Homocysteine, Lipoprotein(a), and Standard Cholesterol Screening as Predictors of Peripheral Arterial Disease" }, { "docid": "44048701", "text": "IMPORTANCE The need for surgery for the majority of patients with displaced proximal humeral fractures is unclear, but its use is increasing. \n OBJECTIVE To evaluate the clinical effectiveness of surgical vs nonsurgical treatment for adults with displaced fractures of the proximal humerus involving the surgical neck. \n DESIGN, SETTING, AND PARTICIPANTS A pragmatic, multicenter, parallel-group, randomized clinical trial, the Proximal Fracture of the Humerus Evaluation by Randomization (PROFHER) trial, recruited 250 patients aged 16 years or older (mean age, 66 years [range, 24-92 years]; 192 [77%] were female; and 249 [99.6%] were white) who presented at the orthopedic departments of 32 acute UK National Health Service hospitals between September 2008 and April 2011 within 3 weeks after sustaining a displaced fracture of the proximal humerus involving the surgical neck. Patients were followed up for 2 years (up to April 2013) and 215 had complete follow-up data. The data for 231 patients (114 in surgical group and 117 in nonsurgical group) were included in the primary analysis. \n INTERVENTIONS Fracture fixation or humeral head replacement were performed by surgeons experienced in these techniques. Nonsurgical treatment was sling immobilization. Standardized outpatient and community-based rehabilitation was provided to both groups. \n MAIN OUTCOMES AND MEASURES Primary outcome was the Oxford Shoulder Score (range, 0-48; higher scores indicate better outcomes) assessed during a 2-year period, with assessment and data collection at 6, 12, and 24 months. Sample size was based on a minimal clinically important difference of 5 points for the Oxford Shoulder Score. Secondary outcomes were the Short-Form 12 (SF-12), complications, subsequent therapy, and mortality. \n RESULTS There was no significant mean treatment group difference in the Oxford Shoulder Score averaged over 2 years (39.07 points for the surgical group vs 38.32 points for the nonsurgical group; difference of 0.75 points [95% CI, -1.33 to 2.84 points]; P = .48) or at individual time points. There were also no significant between-group differences over 2 years in the mean SF-12 physical component score (surgical group: 1.77 points higher [95% CI, -0.84 to 4.39 points]; P = .18); the mean SF-12 mental component score (surgical group: 1.28 points lower [95% CI, -3.80 to 1.23 points]; P = .32); complications related to surgery or shoulder fracture (30 patients in surgical group vs 23 patients in nonsurgical group; P = .28), requiring secondary surgery to the shoulder (11 patients in both groups), and increased or new shoulder-related therapy (7 patients vs 4 patients, respectively; P = .58); and mortality (9 patients vs 5 patients; P = .27). Ten medical complications (2 cardiovascular events, 2 respiratory events, 2 gastrointestinal events, and 4 others) occurred in the surgical group during the postoperative hospital stay. \n CONCLUSIONS AND RELEVANCE Among patients with displaced proximal humeral fractures involving the surgical neck, there was no significant difference between surgical treatment compared with nonsurgical treatment in patient-reported clinical outcomes over 2 years following fracture occurrence. These results do not support the trend of increased surgery for patients with displaced fractures of the proximal humerus. \n TRIAL REGISTRATION isrctn.com Identifier: ISRCTN50850043.", "title": "Surgical vs nonsurgical treatment of adults with displaced fractures of the proximal humerus: the PROFHER randomized clinical trial." }, { "docid": "21301090", "text": "BACKGROUND Patients considered for arterial surgery, have been shown to have a high incidence of coexistent cardiac, vascular and other diseases, affecting operative risk and survival. We developed a systematic workup strategy for detecting these coexistent diseases in our vascular surgical patients, mainly based on non-invasive diagnostic techniques. \n METHODS We evaluated 200 consecutive patients, admitted to the department of vascular surgery in an academic teaching hospital, in order to establish the total incidence of relevant concomitant disorders, the extent to which this screening yielded previously unknown diagnostic information, and the impact on short-term (one year) survival. \n RESULTS Coronary artery disease was present in 46% of the patients; 22% had active ischaemia, newly diagnosed in 5.5%. Impaired cardiac function was found in 37%: severely impaired in 12%, newly diagnosed in 27%. Carotid artery disease was present in 32%: critical stenoses were found in 9%; new diagnoses in 29.9%. Aortic aneurysms were present in 7%, newly diagnosed in 5%. Severe renal artery stenosis was present in 5%, newly diagnosed in 3.5%. Sixteen % of the patients had chronic obstructive pulmonary disease, newly diagnosed in 3.5%, and 4.5% had unexpected disorders, which were all new diagnoses. Overall, new diagnoses were reached in 64.5% of the population, affecting therapeutic strategy immediately in 21% of the patients. The presence of coronary artery disease and of cardiac failure were clearly related to one year survival. \n CONCLUSIONS We conclude that a systematic screening strategy, mainly based on noninvasive techniques, can detect the presence of concomitant diseases in the vascular surgical patient. Most important seem the newly diagnosed diseases altering surgical management in one out of every five patients; they also have important implications for patient prognosis.", "title": "Screening for concomitant diseases in peripheral vascular patients. Results of a systematic approach." }, { "docid": "15925931", "text": "BACKGROUND Whole-body magnetic resonance angiography (WB-MRA) has shown its potential for the non-invasive assessment of nearly the entire arterial vasculature within one examination. Since the presence of extra-cardiac atherosclerosis is associated with an increased risk of coronary events, our goal was to establish the relationship between WB-MRA findings, including a systemic atherosclerosis score index, and the presence of significant coronary artery disease (CAD). \n METHODS WB-MRA was performed on a 1.5T scanner in 50 patients scheduled to undergo elective cardiac catheterization for suspected CAD. In each patient, 40 extra-cardiac vessel segments were evaluated and assigned scores according to their luminal narrowing. The atherosclerosis score index (ASI) was generated as the ratio of summed scores to analyzable segments. \n RESULTS ASI was higher in patients with significant (> 50% stenosis) CAD (n = 27) vs. patients without CAD (n = 22; 1.56 vs. 1.28, p = 0.004). ASI correlated with PROCAM (R = 0.57, p < 0.001) and Framingham (R = 0.36, p = 0.01) risk scores as estimates of the 10-year risk of coronary events. A ROC derived ASI of > 1.54 predicted significant CAD with a sensitivity of 59%, specificity of 86% and a positive predictive value of 84%. Logistic regression revealed ASI > 1.54 as the strongest independent predictor for CAD with a 11-fold increase in likelihood to suffer from significant coronary disease. On the contrary, while 15/27 (55%) of patients with CAD exhibited at least one extra-cardiac stenosis > 50%, only 3/22 (14%) of those patients without CAD did (p = 0.003). The likelihood for an extra-cardiac stenosis when CAD is present differed between vascular territories and ranged from 15% for a carotid stenosis to 44% for a stenosis in the lower extremities. \n CONCLUSION This study provides important new evidence for the close association of extra-cardiac and coronary atherosclerosis. The novel findings that a WB-MRA derived systemic atherosclerosis score index is not only associated with established cardiovascular risk scores but is also predictive of significant CAD suggest its potential prognostic implications and underline the importance to screen for coronary disease in patients with extra-cardiac manifestations of atherosclerosis.", "title": "Prediction of coronary artery disease by a systemic atherosclerosis score index derived from whole-body MR angiography" } ]

[ { "docid": "19205437", "text": "Uncoupling protein 1 (UCP1) plays a central role in nonshivering thermogenesis in brown fat; however, its role in beige fat remains unclear. Here we report a robust UCP1-independent thermogenic mechanism in beige fat that involves enhanced ATP-dependent Ca2+ cycling by sarco/endoplasmic reticulum Ca2+-ATPase 2b (SERCA2b) and ryanodine receptor 2 (RyR2). Inhibition of SERCA2b impairs UCP1-independent beige fat thermogenesis in humans and mice as well as in pigs, a species that lacks a functional UCP1 protein. Conversely, enhanced Ca2+ cycling by activation of α1- and/or β3-adrenergic receptors or the SERCA2b-RyR2 pathway stimulates UCP1-independent thermogenesis in beige adipocytes. In the absence of UCP1, beige fat dynamically expends glucose through enhanced glycolysis, tricarboxylic acid metabolism and pyruvate dehydrogenase activity for ATP-dependent thermogenesis through the SERCA2b pathway; beige fat thereby functions as a 'glucose sink' and improves glucose tolerance independently of body weight loss. Our study uncovers a noncanonical thermogenic mechanism through which beige fat controls whole-body energy homeostasis via Ca2+ cycling.", "title": "UCP1-independent signaling involving SERCA2b-mediated calcium cycling regulates beige fat thermogenesis and systemic glucose homeostasis" } ]

[ { "docid": "14865329", "text": "Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders.", "title": "Brown Fat and Browning for the Treatment of Obesity and Related Metabolic Disorders" }, { "docid": "25050364", "text": "OBJECTIVE The proinflammatory cytokine interleukin-18 (IL-18) putatively modulates food intake and energy metabolism, but the effects of IL-18 in high-fat diet fed animals are unknown. Whether IL-18 alters basal metabolic rate or metabolic processes of living is unknown. Here, we tested the hypothesis that IL-18 modulates weight gain, energy intake, whole-body energy expenditure, and utilization of lipid as a fuel substrate in high-fat diet fed mice. \n METHODS Food intake, whole-body metabolism, and motor activity of IL-18 knockout mice were compared to those of wildtype littermates; anorectic effects of intracerebroventricular IL-18 administration were compared between IL-18 receptor knockout, IL-18/IL-18R knockout and wildtype mice. \n RESULTS Chow-reared IL-18 knockout mice were overweight at 6 months of age and then gained excess weight on both low-fat and high-fat diets, ate more high-fat diet, and showed reduced whole-body energy expenditure and increased respiratory exchange ratios. Reductions in energy expenditure of IL-18 knockout mice were seen across fasting vs. feeding conditions, low- vs. high-fat diets, high vs. low levels of physical activity and times of day, suggesting actions on basal metabolic rate. The circadian amplitude of energy expenditure, but not respiratory exchange ratio, food intake, or motor activity, also was blunted in IL-18 knockout mice. Central IL-18 administration reduced high-fat diet intake in wildtype mice, but not in mice lacking the IL-18 receptor. \n CONCLUSION The loss-of-function results support the hypothesis that endogenous IL-18 suppresses appetite and promote energy expenditure and lipid fuel substrate utilization not only during sickness, but also in healthy adults consuming high-fat diets.", "title": "Interleukin-18 null mutation increases weight and food intake and reduces energy expenditure and lipid substrate utilization in high-fat diet fed mice" }, { "docid": "23369842", "text": "Twenty-four hour whole body indirect calorimetry has been used to study the effects of feeding, during a sedentary test day, isoenergetic diets which varied in fat (3 or 40 per cent of total energy) and carbohydrate (82 or 45 per cent) content. Three groups of women were studied: lean, obese and 'post-obese' after slimming. Energy expenditure was greater in absolute terms in the obese women. Twenty-four hour energy expenditure was lower by only 3-7 per cent when fasting compared to that when fed to achieve energy balance. There were no large differences in energy expenditure between the two diets or between the groups but the thermogenic effect of the high carbohydrate diet was significantly greater than that of the high fat diet (5.8 vs 3.5 per cent of energy expenditure: P less than 0.01). The post-obese tended to have lower energy expenditure per kg FFM than controls when fasting and when high-fat fed, but this pattern was not shown by the obese. Sleeping energy expenditure was particularly low in the post-obese group when high-fat fed. Dirunal variations in RQ appear to show more marked rise in morning RQ from the nocturnal minimum in the obese and post-obese, which might be evidence for an energy-saving mechanism through greater availability of stored dietary carbohydrate.", "title": "Metabolic effects of isoenergetic nutrient exchange over 24 hours in relation to obesity in women." }, { "docid": "15535511", "text": "Dopaminergic midbrain neurons integrate signals on food palatability and food-associated reward into the complex control of energy homeostasis. To define the role of insulin receptor (IR) signaling in this circuitry, we inactivated IR signaling in tyrosine hydroxylase (Th)-expressing cells of mice (IR(ΔTh)). IR inactivation in Th-expressing cells of mice resulted in increased body weight, increased fat mass, and hyperphagia. While insulin acutely stimulated firing frequency in 50% of dopaminergic VTA/SN neurons, this response was abolished in IR(ΔTh) mice. Moreover, these mice exhibited an altered response to cocaine under food-restricted conditions. Taken together, these data provide in vivo evidence for a critical role of insulin signaling in catecholaminergic neurons to control food intake and energy homeostasis.", "title": "Role for insulin signaling in catecholaminergic neurons in control of energy homeostasis." }, { "docid": "17973161", "text": "Uncoupling protein 1 (UCP1) is highly expressed in brown adipose tissue, where it generates heat by uncoupling electron transport from ATP production. UCP1 is also found outside classical brown adipose tissue depots, in adipocytes that are termed 'brite' (brown-in-white) or 'beige'. In humans, the presence of brite or beige (brite/beige) adipocytes is correlated with a lean, metabolically healthy phenotype, but whether a causal relationship exists is not clear. Here we report that human brite/beige adipocyte progenitors proliferate in response to pro-angiogenic factors, in association with expanding capillary networks. Adipocytes formed from these progenitors transform in response to adenylate cyclase activation from being UCP1 negative to being UCP1 positive, which is a defining feature of the beige/brite phenotype, while displaying uncoupled respiration. When implanted into normal chow-fed, or into high-fat diet (HFD)-fed, glucose-intolerant NOD-scid IL2rg(null) (NSG) mice, brite/beige adipocytes activated in vitro enhance systemic glucose tolerance. These adipocytes express neuroendocrine and secreted factors, including the pro-protein convertase PCSK1, which is strongly associated with human obesity. Pro-angiogenic conditions therefore drive the proliferation of human beige/brite adipocyte progenitors, and activated beige/brite adipocytes can affect systemic glucose homeostasis, potentially through a neuroendocrine mechanism.", "title": "Human ‘brite / beige’ adipocytes develop from capillary networks and their implantation improves metabolic homeostasis in mice" }, { "docid": "11742219", "text": "Galanin (GAL) is known to stimulate feeding behavior. This peptide has different properties and functions from other feeding stimulants, e.g., neuropeptide Y and agouti-related protein. Hypothalamic GAL is relatively unresponsive to food deprivation and to changes in corticosterone, glucose utilization, dietary carbohydrate and leptin. This indicates that this peptide is not essential under conditions when food is scarce or low-energy, high-carbohydrate diets are being consumed. In contrast, recent evidence suggests that GAL in the paraventricular nucleus (PVN) functions in close relation to dietary fat and alcohol. In particular, it mediates functions that allow animals to adapt to conditions of positive energy balance involving excess consumption of these nutrients. This peptide in the PVN is stimulated by a high-fat diet and also by alcohol. It is stimulated by an increase in circulating lipids caused by a fat-rich meal or alcohol consumption, and it rises during the middle of the active feeding cycle, when fat consumption and triglycerides naturally rise. When centrally injected, GAL in the PVN increases the consumption of food and alcohol. Moreover, it produces a significantly stronger feeding response in rats maintained on a fat-rich diet, which also promotes alcohol intake. This evidence supports the existence of non-homeostatic, positive feedback circuits between GAL and both dietary fat and alcohol. These circuits are believed to contribute to the large meal size, over-consumption of alcohol, and obesity which are generally associated with fat-rich foods.", "title": "Regulation and effects of hypothalamic galanin: relation to dietary fat, alcohol ingestion, circulating lipids and energy homeostasis." }, { "docid": "21547032", "text": "Objective:In mice and in humans, treatment with the second-generation antipsychotic drug olanzapine (OLZ) produces excessive weight gain, adiposity and secondary metabolic complications, including loss of glucose and insulin homeostasis. In mice consuming a high-fat (HF) diet, a similar phenotype develops, which is inhibited by the analgesic acetaminophen (APAP) and by the antioxidant tetrahydroindenoindole (THII). Therefore, we examined the ability of APAP and THII to prevent metabolic changes in mice receiving OLZ.Design and Measurement:C57BL/6J mice received either a normal diet or a HF diet, and were administered daily dosages of OLZ (3 mg kg−1 body weight), alone or with APAP (30 mg kg−1 body weight) or THII (4.5 mg kg−1 body weight), for 10 weeks. Parameters of body composition and metabolism, including glucose and insulin homeostasis and oxidative stress, were examined. Results:OLZ treatment doubled the HF diet-induced increases in body weight and percent body fat. These increases were partially prevented by both APAP and THII, although food consumption was constant in all groups. The THII protection was associated with an increase in whole body and mitochondrial respiration. OLZ also exacerbated, and both APAP and THII prevented, HF diet-induced loss of glucose tolerance and insulin resistance. As increased body fat promotes insulin resistance by a pathway involving oxidative stress, we evaluated production of reactive oxygen and lipid peroxidation in white adipose tissue (WAT). HF diet caused an increase in lipid peroxidation, NADPH-dependent O2 uptake and H2O2 production, which were further exacerbated by OLZ. APAP, THII and the NADPH oxidase inhibitor, diphenyleneiodonium chloride, each abolished oxidative stress in WAT.Conclusions:We conclude that both APAP and THII intervene in the development of obesity and metabolic complications associated with OLZ treatment.", "title": "Protection from olanzapine-induced metabolic toxicity in mice by acetaminophen and tetrahydroindenoindole" }, { "docid": "11201004", "text": "Little is known about longitudinal associations between added sugar consumption (solid and liquid sources) and glucose-insulin homeostasis among youth. Caucasian children (8-10 y) with at least one obese biological parent were recruited in the QUébec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort (n = 630) and followed-up 2 y later (n = 564). Added sugars were assessed by 3 24-h dietary recalls at baseline. Two-year changes were examined in multivariate linear regression models, adjusting for baseline level, age, sex, Tanner stage, energy intake, fat mass (dual-energy X-ray absorptiometry), and physical activity (7 d accelerometer). Added sugar intake in either liquid or solid sources was not related to changes in adiposity measures (fat mass, body mass index, or waist circumference). However, a higher consumption (10 g/d) of added sugars from liquid sources was associated with 0.04 mmol/L higher fasting glucose, 2.3 pmol/L higher fasting insulin, 0.1 unit higher homeostasis model assessment of insulin resistance (HOMA-IR), and 0.4 unit lower Matsuda-insulin sensitivity index (Matsuda-ISI) in all participants (P < 0.01). No associations were observed with consumption of added sugars from solid sources. Overweight/obese children at baseline had greater increases in adiposity indicators, fasting insulin, and HOMA-IR and decreases in Matsuda-ISI during those 2 y than normal-weight children. Consumption of added sugars from liquid or solid sources was not associated with changes in adiposity, but liquid added sugars were a risk factor for the development of impaired glucose homeostasis and insulin resistance over 2 y among youth at risk of obesity.", "title": "Consumption of added sugars from liquid but not solid sources predicts impaired glucose homeostasis and insulin resistance among youth at risk of obesity." }, { "docid": "11428884", "text": "Adipose tissue is an important metabolic organ, the dysfunction of which is associated with the development of obesity, diabetes mellitus, and cardiovascular disease. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is considered the master regulator of adipocyte differentiation and function. Although its cell-autonomous role in adipogenesis has been clearly demonstrated in cell culture, previous fat-specific knockouts of the murine PPARγ gene did not demonstrate a dramatic phenotype in vivo. Here, using Adipoq-Cre mice to drive adipose-specific recombination, we report a unique fat-specific PPARγ knockout (PPARγ FKO) mouse model with almost no visible brown and white adipose tissue at age 3 mo. As a consequence, PPARγ FKO mice had hugely enlarged pancreatic islets, massive fatty livers, and dramatically elevated levels of blood glucose and serum insulin accompanied by extreme insulin resistance. PPARγ FKO mice also exhibited delayed hair coat formation associated with absence of dermal fat, disrupted mammary gland development with loss of mammary fat pads, and high bone mass with loss of bone marrow fat, indicating the critical roles of adipose PPARγ in these tissues. Together, our data reveal the necessity of fat PPARγ in adipose formation, whole-body metabolic homeostasis, and normal development of fat-containing tissues.", "title": "Lipoatrophy and severe metabolic disturbance in mice with fat-specific deletion of PPARγ." }, { "docid": "1590744", "text": "The AMP-activated protein kinase (AMPK) is a key regulator of cellular and whole-body energy homeostasis, which acts to restore energy homoeostasis whenever cellular energy charge is depleted. Over the last 2 decades, it has become apparent that AMPK regulates several other cellular functions and has specific roles in cardiovascular tissues, acting to regulate cardiac metabolism and contractile function, as well as promoting anticontractile, anti-inflammatory, and antiatherogenic actions in blood vessels. In this review, we discuss the role of AMPK in the cardiovascular system, including the molecular basis of mutations in AMPK that alter cardiac physiology and the proposed mechanisms by which AMPK regulates vascular function under physiological and pathophysiological conditions.", "title": "AMP-Activated Protein Kinase: An Ubiquitous Signaling Pathway With Key Roles in the Cardiovascular System" }, { "docid": "11238784", "text": "Liver X receptors (LXRs) and farnesoid X receptor (FXR) are nuclear receptors that function as intracellular sensors for sterols and bile acids, respectively. In response to their ligands, these receptors induce transcriptional responses that maintain a balanced, finely tuned regulation of cholesterol and bile acid metabolism. LXRs also permit the efficient storage of carbohydrate- and fat-derived energy, whereas FXR activation results in an overall decrease in triglyceride levels and modulation of glucose metabolism. The elegant, dual interplay between these two receptor systems suggests that they coevolved to constitute a highly sensitive and efficient system for the maintenance of total body fat and cholesterol homeostasis. Emerging evidence suggests that the tissue-specific action of these receptors is also crucial for the proper function of the cardiovascular, immune, reproductive, endocrine pancreas, renal, and central nervous systems. Together, LXRs and FXR represent potential therapeutic targets for the treatment and prevention of numerous metabolic and lipid-related diseases.", "title": "LXRS and FXR: the yin and yang of cholesterol and fat metabolism." }, { "docid": "23017040", "text": "Reduced dietary methionine intake (0.17% methionine, MR) and calorie restriction (CR) prolong lifespan in male Fischer 344 rats. Although the mechanisms are unclear, both regimens feature lower body weight and reductions in adiposity. Reduced fat deposition in CR is linked to preservation of insulin responsiveness in older animals. These studies examine the relationship between insulin responsiveness and visceral fat in MR and test whether, despite lower food intake observed in MR animals, decreased visceral fat accretion and preservation of insulin sensitivity is not secondary to CR. Accordingly, rats pair fed (pf) control diet (0.86% methinone, CF) to match the food intake of MR for 80 weeks exhibit insulin, glucose, and leptin levels similar to control-fed animals and comparable amounts of visceral fat. Conversely, MR rats show significantly reduced visceral fat compared to CF and PF with concomitant decreases in basal insulin, glucose, and leptin, and increased adiponectin and triiodothyronine. Daily energy expenditure in MR animals significantly exceeds that of both PF and CF. In a separate cohort, insulin responses of older MR animals as measured by oral glucose challenge are similar to young animals. Longitudinal assessments of MR and CF through 112 weeks of age reveal that MR prevents age-associated increases in serum lipids. By 16 weeks, MR animals show a 40% reduction in insulin-like growth factor-1 (IGF-1) that is sustained throughout life; CF IGF-1 levels decline much later, beginning at 112 weeks. Collectively, the results indicate that MR reduces visceral fat and preserves insulin activity in aging rats independent of energy restriction.", "title": "Methionine restriction decreases visceral fat mass and preserves insulin action in aging male Fischer 344 rats independent of energy restriction." }, { "docid": "20363389", "text": "In order to elucidate energy balance in the skeletal muscle, we cloned cDNA of a homologue of uncoupling protein (UCP) from rat skeletal muscle. We also cloned rat UCP-2 cDNA from rat brown adipose tissue (BAT). The UCP cloned from rat skeletal muscle showed 57% and 72% identity with rat UCP-1 and UCP-2. The mRNA was expressed abundantly in the skeletal muscle, moderately in the BAT, and slightly in the white adipose tissue (WAT) with a major band at 2.5 kb and a minor band at 2.8 kb, while the UCP-2 gene expression was widely detected in the whole body with substantial levels in the WAT and with slight levels in the skeletal muscle and BAT. The rat UCP cloned in the present study showed 86% identity with the recently cloned human UCP-3, which was also expressed abundantly in the skeletal muscle with a signal of 2.4 kb. Therefore, the rat UCP was considered to be rat UCP-3. In rats fed high-fat diet the UCP-3 gene expression was augmented 2-fold in the skeletal muscle while UCP-2 mRNA levels were increased significantly (1.6-fold) in the epididymal WAT. Augmented expression of UCPs may provide defense against high-fat induced obesity and impairment of glucose metabolism.", "title": "Cloning of rat uncoupling protein-3 and uncoupling protein-2 cDNAs: their gene expression in rats fed high-fat diet." }, { "docid": "17231273", "text": "Energy deficiency and dysfunction of the Na+, K+-ATPase are common consequences of many pathological insults. The nature and mechanism of cell injury induced by impaired Na+, K+-ATPase, however, are not well defined. We used cultured cortical neurons to examine the hypothesis that blocking the Na+, K+-ATPase induces apoptosis by depleting cellular K+ and, concurrently, induces necrotic injury in the same cells by increasing intracellular Ca2+ and Na+. The Na+, K+-ATPase inhibitor ouabain induced concentration-dependent neuronal death. Ouabain triggered transient neuronal cell swelling followed by cell shrinkage, accompanied by intracellular Ca2+ and Na+ increase, K+ decrease, cytochrome c release, caspase-3 activation, and DNA laddering. Electron microscopy revealed the coexistence of ultrastructural features of both apoptosis and necrosis in individual cells. The caspase inhibitor Z-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD-FMK) blocked >50% of ouabain-induced neuronal death. Potassium channel blockers or high K+ medium, but not Ca2+ channel blockade, prevented cytochrome c release, caspase activation, and DNA damage. Blocking of K+, Ca2+, or Na+ channels or high K+ medium each attenuated the ouabain-induced cell death; combined inhibition of K+ channels and Ca2+ or Na+ channels resulted in additional protection. Moreover, coapplication of Z-VAD-FMK and nifedipine produced virtually complete neuroprotection. These results suggest that the neuronal death associated with Na+, K+-pump failure consists of concurrent apoptotic and necrotic components, mediated by intracellular depletion of K+ and accumulation of Ca2+ and Na+, respectively. The ouabain-induced hybrid death may represent a distinct form of cell death related to the brain injury of inadequate energy supply and disrupted ion homeostasis.", "title": "Ionic mechanism of ouabain-induced concurrent apoptosis and necrosis in individual cultured cortical neurons" }, { "docid": "36558211", "text": "OBJECTIVES To explore the different characteristics of high and low fat consumers, in particular their macronutrient intake and body mass index. \n DESIGN Reanalysis of data from the Dietary and Nutritional Survey of British Adults. Comparisons were made between groups defined as high and low fat consumers on the basis of 7-day weighed food records considered to be valid for energy intake. Individuals were classified in two ways according to the percentage energy from fat (FAT%) and the absolute amount of fat consumed (FATg). The criteria for classification of the high FAT% being > 45% (high fat) and < or = 35% (low fat). For the FATg group the threshold for the high fat group was > 138 g/day (men) and > 102 g/day (women), and for the low fat group < 85 g/day (men) and < 70 g/day (women). \n SETTING Dietary data was collected from private households in Great Britain between 1986 and 1987. SUBJECTS From the total population of 2197, individuals who were slimming, ill or had an EI: BMR of < 1.2 were excluded in order to use data which was most likely to represent habitual energy intakes. From the remaining 1240 subjects, 10.8% of this sample (6.1% of the total population) were classified as low fat consumers (76 men and 58 women) and 15.4% high fat (8.7% of the total population, 93 men and 98 women). \n MAIN OUTCOME MEASURES Macronutrient consumption and body mass index (BMI). \n RESULTS 30% of the subjects changed fat group classification when the criteria of defining high and low fat groups altered from FAT% to FATg. Nutrient intakes differed according to definition of the groups. The high fat FATg group ate significantly more of all nutrients than the low fat FATg group. However, this was not seen for the FAT% analysis, with the high fat group eating more fat and less carbohydrate. The average BMI tended to be higher in the high fat than the low fat groups, particularly in the FATg analysis. However, the high fat group contained a wide range of BMIs. Further exploration of BMI in the high fat groups, showed that age (an 11-year difference) was the only variable to distinguish individuals in the top and bottom quartiles of BMI. \n CONCLUSIONS High and low fat consumers differ according to a number of variables, and this is affected by how these groups are defined (FAT% or FATg). High fat consumers tend to have a higher BMI than low fat consumers, but not all high fat consumers are overweight or obese.", "title": "High and low fat consumers, their macronutrient intake and body mass index: further analysis of the National Diet and Nutrition Survey of British Adults." }, { "docid": "12994780", "text": "Rationale:Atypical antipsychotic drugs (AAD) induce significant weight gain in female C57BL/6J mice. The effect of dietary fat on weight gain and serum lipids in this model is unknown. Objectives: Test the hypothesis that the obesigenic effects of these drugs are greater in the presence of a high-fat diet. Methods:Female C57BL/6J mice were treated with atypical antipsychotics for 3 weeks and fed either a low-fat or high-fat diet (4.6 vs 15.6% fat by wt). Food intake (FI), body weight (BW), body composition, and serum lipids were measured during treatment with optimized doses of olanzapine, quetiapine, and risperidone. Energy intake (EI) and feed efficiency (FE) were calculated. Group differences in change were analyzed via repeated measures analysis of variance (ANOVA). Serum lipid concentrations, EI and FE were compared using two-way ANOVA.Results:AAD-treated mice gained significantly more weight than controls after 3 weeks (P<0.001). Treatment and diet had significant effects on FI and EI over time (P<0.001). AAD-treated mice had significantly higher FE than controls (P<0.05); however, there was no significant drug by diet interaction (P=0.65). Risperidone low-fat mice gained significantly more absolute fat mass than placebo low-fat mice (P<0.05). All treatment groups, except quetiapine low-fat and olanzapine high-fat, gained significantly more absolute lean mass than placebo controls (P<0.05). Cholesterol levels were significantly lower in quetiapine and risperidone than placebo (P<0.05). Risperidone low-fat mice had significantly higher triglyceride levels than placebo and risperidone high-fat mice (P<0.05).Conclusions:A high-fat diet does not increase AAD-induced BW gain in female mice during a 3-week treatment period.", "title": "No effect of dietary fat on short-term weight gain in mice treated with atypical antipsychotic drugs" }, { "docid": "17150648", "text": "Glial cells perform critical functions that alter the metabolism and activity of neurons, and there is increasing interest in their role in appetite and energy balance. Leptin, a key regulator of appetite and metabolism, has previously been reported to influence glial structural proteins and morphology. Here, we demonstrate that metabolic status and leptin also modify astrocyte-specific glutamate and glucose transporters, indicating that metabolic signals influence synaptic efficacy and glucose uptake and, ultimately, neuronal function. We found that basal and glucose-stimulated electrical activity of hypothalamic proopiomelanocortin (POMC) neurons in mice were altered in the offspring of mothers fed a high-fat diet. In adulthood, increased body weight and fasting also altered the expression of glucose and glutamate transporters. These results demonstrate that whole-organism metabolism alters hypothalamic glial cell activity and suggest that these cells play an important role in the pathology of obesity.", "title": "Leptin regulates glutamate and glucose transporters in hypothalamic astrocytes." }, { "docid": "1365188", "text": "Several data suggest that fermentable dietary fiber could play a role in the control of obesity and associated metabolic disorders. The aim of this study was to investigate the putative role of short chain fructo-oligosaccharide (OFS) - a non-digestible oligosaccharide - in mice fed a standard diet and in mice fed two distinct high fat diets inducing metabolic disorders associated to obesity. We confirmed, in mice, several effects previously shown in rats fed a standard diet enriched with OFS, namely an increase in total and empty caecum weight, a significant decrease in epididymal fat mass, and an increase in colonic and portal plasma glucagon-like peptide-1 (GLP-1), a phenomenon positively correlated with a higher colonic proglucagon mRNA level. Curiously, 4-week treatment with OFS added at the same dose induced different effects when added in the two different high fat diets. OFS decreased energy intake, body weight gain, glycemia, and epididymal fat mass only when added together with the high fat-carbohydrate free diet, in which OFS promoted colonic proglucagon expression and insulin secretion. Our results support an association between the increase in proglucagon expression in the proximal colon and OFS effects on glycemia, fat mass development, and/or body weight gain. In conclusion, dietary oligosaccharides would constitute an interesting class of dietary fibers promoting, in certain conditions, endogenous GLP-1 production, with beneficial physiological consequences. This remains to be proven in human studies.", "title": "Relation between colonic proglucagon expression and metabolic response to oligofructose in high fat diet-fed mice." }, { "docid": "33918970", "text": "OBJECTIVE Oligofructose (OFS) is a prebiotic that reduces energy intake and fat mass via changes in gut satiety hormones and microbiota. The effects of OFS may vary depending on predisposition to obesity. The aim of this study was to examine the effect of OFS in diet-induced obese (DIO) and diet-resistant (DR) rats. \n METHODS Adult, male DIO, and DR rats were randomized to: high-fat/high-sucrose (HFS) diet or HFS diet + 10% OFS for 6 weeks. Body composition, food intake, gut microbiota, plasma gut hormones, and cannabinoid CB(1) receptor expression in the nodose ganglia were measured. \n RESULTS OFS reduced body weight, energy intake, and fat mass in both phenotypes (P < 0.05). Select gut microbiota differed in DIO versus DR rats (P < 0.05), the differences being eliminated by OFS. OFS did not modify plasma ghrelin or CB(1) expression in nodose ganglia, but plasma levels of GIP were reduced and PYY were elevated (P < 0.05) by OFS. \n CONCLUSIONS OFS was able to reduce body weight and adiposity in both prone and resistant obese phenotypes. OFS-induced changes in gut microbiota profiles in DIO and DR rats, along with changes in gut hormone levels, likely contribute to the sustained lower body weights.", "title": "Interactive effects of oligofructose and obesity predisposition on gut hormones and microbiota in diet-induced obese rats." } ]

[ { "docid": "19205437", "text": "Uncoupling protein 1 (UCP1) plays a central role in nonshivering thermogenesis in brown fat; however, its role in beige fat remains unclear. Here we report a robust UCP1-independent thermogenic mechanism in beige fat that involves enhanced ATP-dependent Ca2+ cycling by sarco/endoplasmic reticulum Ca2+-ATPase 2b (SERCA2b) and ryanodine receptor 2 (RyR2). Inhibition of SERCA2b impairs UCP1-independent beige fat thermogenesis in humans and mice as well as in pigs, a species that lacks a functional UCP1 protein. Conversely, enhanced Ca2+ cycling by activation of α1- and/or β3-adrenergic receptors or the SERCA2b-RyR2 pathway stimulates UCP1-independent thermogenesis in beige adipocytes. In the absence of UCP1, beige fat dynamically expends glucose through enhanced glycolysis, tricarboxylic acid metabolism and pyruvate dehydrogenase activity for ATP-dependent thermogenesis through the SERCA2b pathway; beige fat thereby functions as a 'glucose sink' and improves glucose tolerance independently of body weight loss. Our study uncovers a noncanonical thermogenic mechanism through which beige fat controls whole-body energy homeostasis via Ca2+ cycling.", "title": "UCP1-independent signaling involving SERCA2b-mediated calcium cycling regulates beige fat thermogenesis and systemic glucose homeostasis" } ]

[ { "docid": "4319174", "text": "All homeotherms use thermogenesis to maintain their core body temperature, ensuring that cellular functions and physiological processes can continue in cold environments. In the prevailing model of thermogenesis, when the hypothalamus senses cold temperatures it triggers sympathetic discharge, resulting in the release of noradrenaline in brown adipose tissue and white adipose tissue. Acting via the β(3)-adrenergic receptors, noradrenaline induces lipolysis in white adipocytes, whereas it stimulates the expression of thermogenic genes, such as PPAR-γ coactivator 1a (Ppargc1a), uncoupling protein 1 (Ucp1) and acyl-CoA synthetase long-chain family member 1 (Acsl1), in brown adipocytes. However, the precise nature of all the cell types involved in this efferent loop is not well established. Here we report in mice an unexpected requirement for the interleukin-4 (IL-4)-stimulated program of alternative macrophage activation in adaptive thermogenesis. Exposure to cold temperature rapidly promoted alternative activation of adipose tissue macrophages, which secrete catecholamines to induce thermogenic gene expression in brown adipose tissue and lipolysis in white adipose tissue. Absence of alternatively activated macrophages impaired metabolic adaptations to cold, whereas administration of IL-4 increased thermogenic gene expression, fatty acid mobilization and energy expenditure, all in a macrophage-dependent manner. Thus, we have discovered a role for alternatively activated macrophages in the orchestration of an important mammalian stress response, the response to cold.", "title": "Alternatively activated macrophages produce catecholamines to sustain adaptive thermogenesis" }, { "docid": "14865329", "text": "Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders.", "title": "Brown Fat and Browning for the Treatment of Obesity and Related Metabolic Disorders" }, { "docid": "29691654", "text": "Until recently, the mechanism of adaptive thermogenesis was ascribed to the expression of uncoupling protein 1 (UCP1) in brown and beige adipocytes. UCP1 is known to catalyze a proton leak of the inner mitochondrial membrane, resulting in uncoupled oxidative metabolism with no production of adenosine triphosphate and increased energy expenditure. Thus increasing brown and beige adipose tissue with augmented UCP1 expression is a viable target for obesity-related disorders. Recent work demonstrates an UCP1-independent pathway to uncouple mitochondrial respiration. A secreted enzyme, PM20D1, enriched in UCP1+ adipocytes, exhibits catalytic and hydrolytic activity to reversibly form N-acyl amino acids. N-acyl amino acids act as endogenous uncouplers of mitochondrial respiration at physiological concentrations. Administration of PM20D1 or its products, N-acyl amino acids, to diet-induced obese mice improves glucose tolerance by increasing energy expenditure. In short-term studies, treated animals exhibit no toxicity while experiencing 10% weight loss primarily of adipose tissue. Further study of this metabolic pathway may identify novel therapies for diabesity, the disease state associated with diabetes and obesity.", "title": "Uncoupling Mitochondrial Respiration for Diabesity." }, { "docid": "970012", "text": "Molecular mechanisms underlying the cold-associated high cardiovascular risk remain unknown. Here, we show that the cold-triggered food-intake-independent lipolysis significantly increased plasma levels of small low-density lipoprotein (LDL) remnants, leading to accelerated development of atherosclerotic lesions in mice. In two genetic mouse knockout models (apolipoprotein E(-/-) [ApoE(-/-)] and LDL receptor(-/-) [Ldlr(-/-)] mice), persistent cold exposure stimulated atherosclerotic plaque growth by increasing lipid deposition. Furthermore, marked increase of inflammatory cells and plaque-associated microvessels were detected in the cold-acclimated ApoE(-/-) and Ldlr(-/-) mice, leading to plaque instability. Deletion of uncoupling protein 1 (UCP1), a key mitochondrial protein involved in thermogenesis in brown adipose tissue (BAT), in the ApoE(-/-) strain completely protected mice from the cold-induced atherosclerotic lesions. Cold acclimation markedly reduced plasma levels of adiponectin, and systemic delivery of adiponectin protected ApoE(-/-) mice from plaque development. These findings provide mechanistic insights on low-temperature-associated cardiovascular risks.", "title": "Cold Exposure Promotes Atherosclerotic Plaque Growth and Instability via UCP1-Dependent Lipolysis" }, { "docid": "29362104", "text": "The effect of omega-3, omega-6 and omega-9 unsaturated fatty acids (UFAs) on receptor-mediated Ca2+ entry was investigated in a T-cell line (JURKAT) by using anti-CD3 antibodies (OKT3) to induce intracellular Ca2+ [( Ca2+]i) increase and Ca2+ influx. All the UFAs, as well as Ni2+ ions and 12-O-tetradecanoylphorbol 13-acetate, decreased the OKT3-induced sustained [Ca2+]i increase to basal levels. Although non-esterified fatty acids activate protein kinase C (PKC) [McPhail, Clayton & Snyderman (1984) Science 224, 622-624; Murakami, Chan & Routtenberg (1986) J. Biol. Chem. 261, 15424-15429], studies using H-7 and analysis of the PKC-dependent phosphorylation of 19 and 80 kDa marker substrates ruled out the involvement of PKC in UFA-induced inhibition of Ca2+ entry. Flow-cytometry analysis showed that UFAs do not interfere with antibody-receptor binding. BSA (0.2%, w/v) reversed the effect of UFAs after these fatty acids have decreased the OKT3-induced [Ca2+]i increase to basal levels. The relevance of these findings and possible mechanisms for inhibition by UFAs of receptor-mediated Ca2+ influx were discussed.", "title": "Inhibition of receptor-mediated calcium influx in T cells by unsaturated non-esterified fatty acids." }, { "docid": "17231273", "text": "Energy deficiency and dysfunction of the Na+, K+-ATPase are common consequences of many pathological insults. The nature and mechanism of cell injury induced by impaired Na+, K+-ATPase, however, are not well defined. We used cultured cortical neurons to examine the hypothesis that blocking the Na+, K+-ATPase induces apoptosis by depleting cellular K+ and, concurrently, induces necrotic injury in the same cells by increasing intracellular Ca2+ and Na+. The Na+, K+-ATPase inhibitor ouabain induced concentration-dependent neuronal death. Ouabain triggered transient neuronal cell swelling followed by cell shrinkage, accompanied by intracellular Ca2+ and Na+ increase, K+ decrease, cytochrome c release, caspase-3 activation, and DNA laddering. Electron microscopy revealed the coexistence of ultrastructural features of both apoptosis and necrosis in individual cells. The caspase inhibitor Z-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD-FMK) blocked >50% of ouabain-induced neuronal death. Potassium channel blockers or high K+ medium, but not Ca2+ channel blockade, prevented cytochrome c release, caspase activation, and DNA damage. Blocking of K+, Ca2+, or Na+ channels or high K+ medium each attenuated the ouabain-induced cell death; combined inhibition of K+ channels and Ca2+ or Na+ channels resulted in additional protection. Moreover, coapplication of Z-VAD-FMK and nifedipine produced virtually complete neuroprotection. These results suggest that the neuronal death associated with Na+, K+-pump failure consists of concurrent apoptotic and necrotic components, mediated by intracellular depletion of K+ and accumulation of Ca2+ and Na+, respectively. The ouabain-induced hybrid death may represent a distinct form of cell death related to the brain injury of inadequate energy supply and disrupted ion homeostasis.", "title": "Ionic mechanism of ouabain-induced concurrent apoptosis and necrosis in individual cultured cortical neurons" }, { "docid": "17973161", "text": "Uncoupling protein 1 (UCP1) is highly expressed in brown adipose tissue, where it generates heat by uncoupling electron transport from ATP production. UCP1 is also found outside classical brown adipose tissue depots, in adipocytes that are termed 'brite' (brown-in-white) or 'beige'. In humans, the presence of brite or beige (brite/beige) adipocytes is correlated with a lean, metabolically healthy phenotype, but whether a causal relationship exists is not clear. Here we report that human brite/beige adipocyte progenitors proliferate in response to pro-angiogenic factors, in association with expanding capillary networks. Adipocytes formed from these progenitors transform in response to adenylate cyclase activation from being UCP1 negative to being UCP1 positive, which is a defining feature of the beige/brite phenotype, while displaying uncoupled respiration. When implanted into normal chow-fed, or into high-fat diet (HFD)-fed, glucose-intolerant NOD-scid IL2rg(null) (NSG) mice, brite/beige adipocytes activated in vitro enhance systemic glucose tolerance. These adipocytes express neuroendocrine and secreted factors, including the pro-protein convertase PCSK1, which is strongly associated with human obesity. Pro-angiogenic conditions therefore drive the proliferation of human beige/brite adipocyte progenitors, and activated beige/brite adipocytes can affect systemic glucose homeostasis, potentially through a neuroendocrine mechanism.", "title": "Human ‘brite / beige’ adipocytes develop from capillary networks and their implantation improves metabolic homeostasis in mice" }, { "docid": "36464673", "text": "We show that, in vitro, Ca2+-dependent protein kinase C (PKC) phosphorylates recombinant murine p53 protein on several residues contained within a conserved basic region of 25 amino acids, located in the C-terminal part of the protein. Accordingly, synthetic p53-(357-381)-peptide is phosphorylated by PKC at multiple Ser and Thr residues, including Ser360, Thr365, Ser370 and Thr377. We also establish that p53-(357-381)-peptide at micromolar concentrations has the ability to stimulate sequence-specific DNA binding by p53. That stimulation is lost upon phosphorylation by PKC. To further characterise the mechanisms that regulate PKC-dependent phosphorylation of p53-(357-381)-peptide, the phosphorylation of recombinant p53 and p53-(357-381)-peptide by PKC were compared. The results suggest that phosphorylation of full-length p53 on the C-terminal PKC sites is highly dependent on the accessibility of the phosphorylation sites and that a domain on p53 distinct from p53-(357-381)-peptide is involved in binding PKC. Accordingly, we have identified a conserved 27-amino-acid peptide, p53-(320-346)-peptide, within the C-terminal region of p53 and adjacent to residues 357-381 that interacts with PKC in vitro. The interaction between p53-(320-346)-peptide and PKC inhibits PKC autophosphorylation and the phosphorylation of substrates, including p53-(357-381)-peptide, neurogranin and histone H1. Conventional Ca2+-dependent PKC alpha, beta and gamma and the catalytic fragment of PKC (PKM) were nearly equally susceptible to inhibition by p53-(320-346)-peptide. The Ca2+-independent PKC delta was much less sensitive to inhibition. The significance of these findings for understanding the in vivo phosphorylation of p53 by PKC are discussed.", "title": "The in vitro phosphorylation of p53 by calcium-dependent protein kinase C--characterization of a protein-kinase-C-binding site on p53." }, { "docid": "36838958", "text": "Uncoupling protein 1 (Ucp1), which is localized in the mitochondrial inner membrane of mammalian brown adipose tissue (BAT), generates heat by uncoupling oxidative phosphorylation. Upon cold exposure or nutritional abundance, sympathetic neurons stimulate BAT to express Ucp1 to induce energy dissipation and thermogenesis. Accordingly, increased Ucp1 expression reduces obesity in mice and is correlated with leanness in humans. Despite this significance, there is currently a limited understanding of how Ucp1 expression is physiologically regulated at the molecular level. Here, we describe the involvement of Sestrin2 and reactive oxygen species (ROS) in regulation of Ucp1 expression. Transgenic overexpression of Sestrin2 in adipose tissues inhibited both basal and cold-induced Ucp1 expression in interscapular BAT, culminating in decreased thermogenesis and increased fat accumulation. Endogenous Sestrin2 is also important for suppressing Ucp1 expression because BAT from Sestrin2(-/-) mice exhibited a highly elevated level of Ucp1 expression. The redox-inactive mutant of Sestrin2 was incapable of regulating Ucp1 expression, suggesting that Sestrin2 inhibits Ucp1 expression primarily through reducing ROS accumulation. Consistently, ROS-suppressing antioxidant chemicals, such as butylated hydroxyanisole and N-acetylcysteine, inhibited cold- or cAMP-induced Ucp1 expression as well. p38 MAPK, a signaling mediator required for cAMP-induced Ucp1 expression, was inhibited by either Sestrin2 overexpression or antioxidant treatments. Taken together, these results suggest that Sestrin2 and antioxidants inhibit Ucp1 expression through suppressing ROS-mediated p38 MAPK activation, implying a critical role of ROS in proper BAT metabolism.", "title": "Sestrin2 inhibits uncoupling protein 1 expression through suppressing reactive oxygen species." }, { "docid": "26902591", "text": "Cancer-associated cachexia (CAC) is a wasting syndrome characterized by systemic inflammation, body weight loss, atrophy of white adipose tissue (WAT) and skeletal muscle. Limited therapeutic options are available and the underlying mechanisms are poorly defined. Here we show that a phenotypic switch from WAT to brown fat, a phenomenon termed WAT browning, takes place in the initial stages of CAC, before skeletal muscle atrophy. WAT browning is associated with increased expression of uncoupling protein 1 (UCP1), which uncouples mitochondrial respiration toward thermogenesis instead of ATP synthesis, leading to increased lipid mobilization and energy expenditure in cachectic mice. Chronic inflammation and the cytokine interleukin-6 increase UCP1 expression in WAT, and treatments that reduce inflammation or β-adrenergic blockade reduce WAT browning and ameliorate the severity of cachexia. Importantly, UCP1 staining is observed in WAT from CAC patients. Thus, inhibition of WAT browning represents a promising approach to ameliorate cachexia in cancer patients.", "title": "A switch from white to brown fat increases energy expenditure in cancer-associated cachexia." }, { "docid": "30303335", "text": "Excitation-transcription coupling, linking stimulation at the cell surface to changes in nuclear gene expression, is conserved throughout eukaryotes. How closely related coexpressed transcription factors are differentially activated remains unclear. Here, we show that two Ca2+-dependent transcription factor isoforms, NFAT1 and NFAT4, require distinct sub-cellular InsP3 and Ca2+ signals for physiologically sustained activation. NFAT1 is stimulated by sub-plasmalemmal Ca2+ microdomains, whereas NFAT4 additionally requires Ca2+ mobilization from the inner nuclear envelope by nuclear InsP3 receptors. NFAT1 is rephosphorylated (deactivated) more slowly than NFAT4 in both cytoplasm and nucleus, enabling a more prolonged activation phase. Oscillations in cytoplasmic Ca2+, long considered the physiological form of Ca2+ signaling, play no role in activating either NFAT protein. Instead, effective sustained physiological activation of NFAT4 is tightly linked to oscillations in nuclear Ca2+. Our results show how gene expression can be controlled by coincident yet geographically distinct Ca2+ signals, generated by a freely diffusible InsP3 message.", "title": "Control of NFAT Isoform Activation and NFAT-Dependent Gene Expression through Two Coincident and Spatially Segregated Intracellular Ca2+ Signals" }, { "docid": "7869794", "text": "Ca2+ messages are broadly important in cellular signal transduction. In immune cells, Ca2+ signaling is an essential step in many forms of activation. Neutrophil-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) is one form of leukocyte activation that plays an important role in tumor cell killing in vitro and in patient care. Using fluorescence methodologies, we found that neutrophils exhibit Ca2+ signals during ADCC directed against breast fibrosarcoma cells. Importantly, these signals were localized to Ca2+ microdomains at the neutrophil-to-tumor cell interface where they display dynamic features such as movement, fusion, and fission. These signals were blocked by the intracellular Ca2+ buffer BAPTA. At the neutrophil–tumor cell synapse, the neutrophil’s cytoplasm was enriched in STIM1, a crucial mediator of Ca2+ signaling, whereas the Ca2+-binding proteins calbindin and parvalbumin were not affected. Our findings suggest that Ca2+ microdomains are due to an active signaling process. As Ca2+ signals within neutrophils were necessary for specific tumor cell apoptosis, a central role of microdomains in leukocyte-mediated tumor cell destruction is indicated.", "title": "Calicum microdomains form within neutrophils at the neutrophil–tumor cell synapse: role in antibody-dependent target cell apoptosis" }, { "docid": "37964706", "text": "Ca2+ entry through store-operated Ca2+ channels drives the production of the pro-inflammatory molecule leukotriene C4 (LTC4) from mast cells through a pathway involving Ca2+-dependent protein kinase C, mitogen-activated protein kinases ERK1/2, phospholipase A2, and 5-lipoxygenase. Here we examine whether local Ca2+ influx through store-operated Ca2+ release-activated Ca2+ (CRAC) channels in the plasma membrane stimulates this signaling pathway. Manipulating the amplitude and spatial extent of Ca2+ entry by altering chemical and electrical gradients for Ca2+ influx or changing the Ca2+ buffering of the cytoplasm all impacted on protein kinase C and ERK activation, generation of arachidonic acid and LTC4 secretion, with little change in the bulk cytoplasmic Ca2+ rise. Similar bulk cytoplasmic Ca2+ concentrations were achieved when CRAC channels were activated in 0.25 mm external Ca2+ versus 2 mm Ca2+ and 100 nm La3+, an inhibitor of CRAC channels. However, despite similar bulk cytoplasmic Ca2+, protein kinase C activation and LTC4 secretion were larger in 2 mm Ca2+ and La3+ than in 0.25 mm Ca2+, consistent with the central involvement of a subplasmalemmal Ca2+ rise. The nonreceptor tyrosine kinase Syk coupled CRAC channel opening to protein kinase C and ERK activation. Recombinant TRPC3 channels also activated protein kinase C, suggesting that subplasmalemmal Ca2+ rather than a microdomain exclusive to CRAC channels is the trigger. Hence a subplasmalemmal Ca2+ increase in mast cells is highly versatile in that it triggers cytoplasmic responses through generation of intracellular messengers as well as long distance changes through increased secretion of paracrine signals.", "title": "Local Ca2+ influx through Ca2+ release-activated Ca2+ (CRAC) channels stimulates production of an intracellular messenger and an intercellular pro-inflammatory signal." }, { "docid": "10562341", "text": "The activation of T cells is the fundamental on switch for the adaptive immune system. Ca2+ signaling is essential for T cell activation and starts as initial, short-lived, localized Ca2+ signals. The second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) forms rapidly upon T cell activation and stimulates early Ca2+ signaling. We developed a high-resolution imaging technique using multiple fluorescent Ca2+ indicator dyes to characterize these early signaling events and investigate the channels involved in NAADP-dependent Ca2+ signals. In the first seconds of activation of either primary murine T cells or human Jurkat cells with beads coated with an antibody against CD3, we detected Ca2+ signals with diameters close to the limit of detection and that were close to the activation site at the plasma membrane. In Jurkat cells in which the ryanodine receptor (RyR) was knocked down or in primary T cells from RyR1−/− mice, either these early Ca2+ signals were not detected or the number of signals was markedly reduced. Local Ca2+ signals observed within 20 ms upon microinjection of Jurkat cells with NAADP were also sensitive to RyR knockdown. In contrast, TRPM2 (transient receptor potential channel, subtype melastatin 2), a potential NAADP target channel, was not required for the formation of initial Ca2+ signals in primary T cells. Thus, through our high-resolution imaging method, we characterized early Ca2+ release events in T cells and obtained evidence for the involvement of RyR and NAADP in such signals.", "title": "Frontrunners of T cell activation: Initial, localized Ca2+ signals mediated by NAADP and the type 1 ryanodine receptor" }, { "docid": "34582256", "text": "The object of this study was to assess the role of brown adipose tissue (BAT) and the sympathetic nervous system in the rise in heat production associated with endotoxin-induced fever. Oxygen consumption (VO2) was found to be significantly increased (28%) over a 4-h period after two doses of endotoxin (Escherichia coli lipopolysaccharide, 0.3 mg/100 g body wt) given 24 h apart. Injection of a mixed beta-adrenoceptor antagonist (propranolol) reduced VO2 by 14% in endotoxin-treated rats, whereas the selective beta 1- (atenolol) or beta 2- (ICI 118551) antagonists suppressed VO2 by 10%. These drugs did not affect VO2 in control animals. BAT thermogenic activity assessed from measurements of in vitro mitochondrial guanosine 5'-diphosphate (GDP) binding was elevated by 54% in interscapular BAT and by 171% in other BAT depots. Surgical denervation of one lobe of the interscapular depot prevented these responses. Endotoxin failed to stimulate GDP binding in rats fed protein-deficient diets. This may have been because BAT thermogenic activity was already elevated in control rats fed these diets or because endotoxin caused a marked suppression of food intake in the protein-deficient animals. The results indicate that sympathetic activation of BAT is involved in the thermogenic responses to endotoxin and that these can be modified by dietary manipulation.", "title": "Involvement of sympathetic nervous system and brown fat in endotoxin-induced fever in rats." }, { "docid": "10846815", "text": "The actin cortex both facilitates and hinders the exocytosis of secretory granules. How cells consolidate these two opposing roles was not well understood. Here we show that antigen activation of mast cells induces oscillations in Ca(2+) and PtdIns(4,5)P(2) lipid levels that in turn drive cyclic recruitment of N-WASP and cortical actin level oscillations. Experimental and computational analysis argues that vesicle fusion correlates with the observed actin and Ca(2+) level oscillations. A vesicle secretion cycle starts with the capture of vesicles by actin when cortical F-actin levels are high, followed by vesicle passage through the cortex when F-actin levels are low, and vesicle fusion with the plasma membrane when Ca(2+) levels subsequently increase. Thus, cells employ oscillating levels of Ca(2+), PtdIns(4,5)P(2) and cortical F-actin to increase secretion efficiency, explaining how the actin cortex can function as a carrier as well as barrier for vesicle secretion.", "title": "Coordinated oscillations in cortical actin and Ca2+ correlate with cycles of vesicle secretion" }, { "docid": "5436081", "text": "Dynamic membrane repair and remodelling is an elemental process that maintains cell integrity and mediates efficient cellular function. Here we report that MG53, a muscle-specific tripartite motif family protein (TRIM72), is a component of the sarcolemmal membrane-repair machinery. MG53 interacts with phosphatidylserine to associate with intracellular vesicles that traffic to and fuse with sarcolemmal membranes. Mice null for MG53 show progressive myopathy and reduced exercise capability, associated with defective membrane-repair capacity. Injury of the sarcolemmal membrane leads to entry of the extracellular oxidative environment and MG53 oligomerization, resulting in recruitment of MG53-containing vesicles to the injury site. After vesicle translocation, entry of extracellular Ca2+ facilitates vesicle fusion to reseal the membrane. Our data indicate that intracellular vesicle translocation and Ca2+-dependent membrane fusion are distinct steps involved in the repair of membrane damage and that MG53 may initiate the assembly of the membrane repair machinery in an oxidation-dependent manner.", "title": "MG53 nucleates assembly of cell membrane repair machinery" }, { "docid": "13760557", "text": "Degranulation of mast cells in response to Ag or the calcium mobilizing agent, thapsigargin, is dependent on emptying of intracellular stores of Ca(2+) and the ensuing influx of external Ca(2+), also referred to as store-operated calcium entry. However, it is unlikely that the calcium release-activated calcium channel is the sole mechanism for the entry of Ca(2+) because Sr(2+) and other divalent cations also permeate and support degranulation in stimulated mast cells. In this study we show that influx of Ca(2+) and Sr(2+) as well as degranulation are dependent on the presence of the canonical transient receptor potential (TRPC) channel protein TRPC5, in addition to STIM1 and Orai1, as demonstrated by knock down of each of these proteins by inhibitory RNAs in a rat mast cell (RBL-2H3) line. Overexpression of STIM1 and Orai1, which are known to be essential components of calcium release-activated calcium channel, allows entry of Ca(2+) but not Sr(2+), whereas overexpression of STIM1 and TRPC5 allows entry of both Ca(2+) and Sr(2+). These and other observations suggest that the Sr(2+)-permeable TRPC5 associates with STIM1 and Orai1 in a stoichiometric manner to enhance entry of Ca(2+) to generate a signal for degranulation.", "title": "Canonical transient receptor potential 5 channel in conjunction with Orai1 and STIM1 allows Sr2+ entry, optimal influx of Ca2+, and degranulation in a rat mast cell line." }, { "docid": "14362678", "text": "Mitochondrial permeability transition pore (mPTP) is involved in cardiac dysfunction during chronic β-adrenergic receptor (β-AR) stimulation. The mechanism by which chronic β-AR stimulation leads to mPTP openings is elusive. Here, we show that chronic administration of isoproterenol (ISO) persistently increases the frequency of mPTP openings followed by mitochondrial damage and cardiac dysfunction. Mechanistically, this effect is mediated by phosphorylation of mitochondrial fission protein, dynamin-related protein 1 (Drp1), by Ca2+/calmodulin-dependent kinase II (CaMKII) at a serine 616 (S616) site. Mutating this phosphorylation site or inhibiting Drp1 activity blocks CaMKII- or ISO-induced mPTP opening and myocyte death in vitro and rescues heart hypertrophy in vivo. In human failing hearts, Drp1 phosphorylation at S616 is increased. These results uncover a pathway downstream of chronic β-AR stimulation that links CaMKII, Drp1 and mPTP to bridge cytosolic stress signal with mitochondrial dysfunction in the heart.", "title": "CaMKII induces permeability transition through Drp1 phosphorylation during chronic β-AR stimulation" } ]

[ { "docid": "19205437", "text": "Uncoupling protein 1 (UCP1) plays a central role in nonshivering thermogenesis in brown fat; however, its role in beige fat remains unclear. Here we report a robust UCP1-independent thermogenic mechanism in beige fat that involves enhanced ATP-dependent Ca2+ cycling by sarco/endoplasmic reticulum Ca2+-ATPase 2b (SERCA2b) and ryanodine receptor 2 (RyR2). Inhibition of SERCA2b impairs UCP1-independent beige fat thermogenesis in humans and mice as well as in pigs, a species that lacks a functional UCP1 protein. Conversely, enhanced Ca2+ cycling by activation of α1- and/or β3-adrenergic receptors or the SERCA2b-RyR2 pathway stimulates UCP1-independent thermogenesis in beige adipocytes. In the absence of UCP1, beige fat dynamically expends glucose through enhanced glycolysis, tricarboxylic acid metabolism and pyruvate dehydrogenase activity for ATP-dependent thermogenesis through the SERCA2b pathway; beige fat thereby functions as a 'glucose sink' and improves glucose tolerance independently of body weight loss. Our study uncovers a noncanonical thermogenic mechanism through which beige fat controls whole-body energy homeostasis via Ca2+ cycling.", "title": "UCP1-independent signaling involving SERCA2b-mediated calcium cycling regulates beige fat thermogenesis and systemic glucose homeostasis" } ]

[ { "docid": "14865329", "text": "Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders.", "title": "Brown Fat and Browning for the Treatment of Obesity and Related Metabolic Disorders" }, { "docid": "4319174", "text": "All homeotherms use thermogenesis to maintain their core body temperature, ensuring that cellular functions and physiological processes can continue in cold environments. In the prevailing model of thermogenesis, when the hypothalamus senses cold temperatures it triggers sympathetic discharge, resulting in the release of noradrenaline in brown adipose tissue and white adipose tissue. Acting via the β(3)-adrenergic receptors, noradrenaline induces lipolysis in white adipocytes, whereas it stimulates the expression of thermogenic genes, such as PPAR-γ coactivator 1a (Ppargc1a), uncoupling protein 1 (Ucp1) and acyl-CoA synthetase long-chain family member 1 (Acsl1), in brown adipocytes. However, the precise nature of all the cell types involved in this efferent loop is not well established. Here we report in mice an unexpected requirement for the interleukin-4 (IL-4)-stimulated program of alternative macrophage activation in adaptive thermogenesis. Exposure to cold temperature rapidly promoted alternative activation of adipose tissue macrophages, which secrete catecholamines to induce thermogenic gene expression in brown adipose tissue and lipolysis in white adipose tissue. Absence of alternatively activated macrophages impaired metabolic adaptations to cold, whereas administration of IL-4 increased thermogenic gene expression, fatty acid mobilization and energy expenditure, all in a macrophage-dependent manner. Thus, we have discovered a role for alternatively activated macrophages in the orchestration of an important mammalian stress response, the response to cold.", "title": "Alternatively activated macrophages produce catecholamines to sustain adaptive thermogenesis" }, { "docid": "29691654", "text": "Until recently, the mechanism of adaptive thermogenesis was ascribed to the expression of uncoupling protein 1 (UCP1) in brown and beige adipocytes. UCP1 is known to catalyze a proton leak of the inner mitochondrial membrane, resulting in uncoupled oxidative metabolism with no production of adenosine triphosphate and increased energy expenditure. Thus increasing brown and beige adipose tissue with augmented UCP1 expression is a viable target for obesity-related disorders. Recent work demonstrates an UCP1-independent pathway to uncouple mitochondrial respiration. A secreted enzyme, PM20D1, enriched in UCP1+ adipocytes, exhibits catalytic and hydrolytic activity to reversibly form N-acyl amino acids. N-acyl amino acids act as endogenous uncouplers of mitochondrial respiration at physiological concentrations. Administration of PM20D1 or its products, N-acyl amino acids, to diet-induced obese mice improves glucose tolerance by increasing energy expenditure. In short-term studies, treated animals exhibit no toxicity while experiencing 10% weight loss primarily of adipose tissue. Further study of this metabolic pathway may identify novel therapies for diabesity, the disease state associated with diabetes and obesity.", "title": "Uncoupling Mitochondrial Respiration for Diabesity." }, { "docid": "970012", "text": "Molecular mechanisms underlying the cold-associated high cardiovascular risk remain unknown. Here, we show that the cold-triggered food-intake-independent lipolysis significantly increased plasma levels of small low-density lipoprotein (LDL) remnants, leading to accelerated development of atherosclerotic lesions in mice. In two genetic mouse knockout models (apolipoprotein E(-/-) [ApoE(-/-)] and LDL receptor(-/-) [Ldlr(-/-)] mice), persistent cold exposure stimulated atherosclerotic plaque growth by increasing lipid deposition. Furthermore, marked increase of inflammatory cells and plaque-associated microvessels were detected in the cold-acclimated ApoE(-/-) and Ldlr(-/-) mice, leading to plaque instability. Deletion of uncoupling protein 1 (UCP1), a key mitochondrial protein involved in thermogenesis in brown adipose tissue (BAT), in the ApoE(-/-) strain completely protected mice from the cold-induced atherosclerotic lesions. Cold acclimation markedly reduced plasma levels of adiponectin, and systemic delivery of adiponectin protected ApoE(-/-) mice from plaque development. These findings provide mechanistic insights on low-temperature-associated cardiovascular risks.", "title": "Cold Exposure Promotes Atherosclerotic Plaque Growth and Instability via UCP1-Dependent Lipolysis" }, { "docid": "17973161", "text": "Uncoupling protein 1 (UCP1) is highly expressed in brown adipose tissue, where it generates heat by uncoupling electron transport from ATP production. UCP1 is also found outside classical brown adipose tissue depots, in adipocytes that are termed 'brite' (brown-in-white) or 'beige'. In humans, the presence of brite or beige (brite/beige) adipocytes is correlated with a lean, metabolically healthy phenotype, but whether a causal relationship exists is not clear. Here we report that human brite/beige adipocyte progenitors proliferate in response to pro-angiogenic factors, in association with expanding capillary networks. Adipocytes formed from these progenitors transform in response to adenylate cyclase activation from being UCP1 negative to being UCP1 positive, which is a defining feature of the beige/brite phenotype, while displaying uncoupled respiration. When implanted into normal chow-fed, or into high-fat diet (HFD)-fed, glucose-intolerant NOD-scid IL2rg(null) (NSG) mice, brite/beige adipocytes activated in vitro enhance systemic glucose tolerance. These adipocytes express neuroendocrine and secreted factors, including the pro-protein convertase PCSK1, which is strongly associated with human obesity. Pro-angiogenic conditions therefore drive the proliferation of human beige/brite adipocyte progenitors, and activated beige/brite adipocytes can affect systemic glucose homeostasis, potentially through a neuroendocrine mechanism.", "title": "Human ‘brite / beige’ adipocytes develop from capillary networks and their implantation improves metabolic homeostasis in mice" }, { "docid": "36838958", "text": "Uncoupling protein 1 (Ucp1), which is localized in the mitochondrial inner membrane of mammalian brown adipose tissue (BAT), generates heat by uncoupling oxidative phosphorylation. Upon cold exposure or nutritional abundance, sympathetic neurons stimulate BAT to express Ucp1 to induce energy dissipation and thermogenesis. Accordingly, increased Ucp1 expression reduces obesity in mice and is correlated with leanness in humans. Despite this significance, there is currently a limited understanding of how Ucp1 expression is physiologically regulated at the molecular level. Here, we describe the involvement of Sestrin2 and reactive oxygen species (ROS) in regulation of Ucp1 expression. Transgenic overexpression of Sestrin2 in adipose tissues inhibited both basal and cold-induced Ucp1 expression in interscapular BAT, culminating in decreased thermogenesis and increased fat accumulation. Endogenous Sestrin2 is also important for suppressing Ucp1 expression because BAT from Sestrin2(-/-) mice exhibited a highly elevated level of Ucp1 expression. The redox-inactive mutant of Sestrin2 was incapable of regulating Ucp1 expression, suggesting that Sestrin2 inhibits Ucp1 expression primarily through reducing ROS accumulation. Consistently, ROS-suppressing antioxidant chemicals, such as butylated hydroxyanisole and N-acetylcysteine, inhibited cold- or cAMP-induced Ucp1 expression as well. p38 MAPK, a signaling mediator required for cAMP-induced Ucp1 expression, was inhibited by either Sestrin2 overexpression or antioxidant treatments. Taken together, these results suggest that Sestrin2 and antioxidants inhibit Ucp1 expression through suppressing ROS-mediated p38 MAPK activation, implying a critical role of ROS in proper BAT metabolism.", "title": "Sestrin2 inhibits uncoupling protein 1 expression through suppressing reactive oxygen species." }, { "docid": "26902591", "text": "Cancer-associated cachexia (CAC) is a wasting syndrome characterized by systemic inflammation, body weight loss, atrophy of white adipose tissue (WAT) and skeletal muscle. Limited therapeutic options are available and the underlying mechanisms are poorly defined. Here we show that a phenotypic switch from WAT to brown fat, a phenomenon termed WAT browning, takes place in the initial stages of CAC, before skeletal muscle atrophy. WAT browning is associated with increased expression of uncoupling protein 1 (UCP1), which uncouples mitochondrial respiration toward thermogenesis instead of ATP synthesis, leading to increased lipid mobilization and energy expenditure in cachectic mice. Chronic inflammation and the cytokine interleukin-6 increase UCP1 expression in WAT, and treatments that reduce inflammation or β-adrenergic blockade reduce WAT browning and ameliorate the severity of cachexia. Importantly, UCP1 staining is observed in WAT from CAC patients. Thus, inhibition of WAT browning represents a promising approach to ameliorate cachexia in cancer patients.", "title": "A switch from white to brown fat increases energy expenditure in cancer-associated cachexia." }, { "docid": "36464673", "text": "We show that, in vitro, Ca2+-dependent protein kinase C (PKC) phosphorylates recombinant murine p53 protein on several residues contained within a conserved basic region of 25 amino acids, located in the C-terminal part of the protein. Accordingly, synthetic p53-(357-381)-peptide is phosphorylated by PKC at multiple Ser and Thr residues, including Ser360, Thr365, Ser370 and Thr377. We also establish that p53-(357-381)-peptide at micromolar concentrations has the ability to stimulate sequence-specific DNA binding by p53. That stimulation is lost upon phosphorylation by PKC. To further characterise the mechanisms that regulate PKC-dependent phosphorylation of p53-(357-381)-peptide, the phosphorylation of recombinant p53 and p53-(357-381)-peptide by PKC were compared. The results suggest that phosphorylation of full-length p53 on the C-terminal PKC sites is highly dependent on the accessibility of the phosphorylation sites and that a domain on p53 distinct from p53-(357-381)-peptide is involved in binding PKC. Accordingly, we have identified a conserved 27-amino-acid peptide, p53-(320-346)-peptide, within the C-terminal region of p53 and adjacent to residues 357-381 that interacts with PKC in vitro. The interaction between p53-(320-346)-peptide and PKC inhibits PKC autophosphorylation and the phosphorylation of substrates, including p53-(357-381)-peptide, neurogranin and histone H1. Conventional Ca2+-dependent PKC alpha, beta and gamma and the catalytic fragment of PKC (PKM) were nearly equally susceptible to inhibition by p53-(320-346)-peptide. The Ca2+-independent PKC delta was much less sensitive to inhibition. The significance of these findings for understanding the in vivo phosphorylation of p53 by PKC are discussed.", "title": "The in vitro phosphorylation of p53 by calcium-dependent protein kinase C--characterization of a protein-kinase-C-binding site on p53." }, { "docid": "38143689", "text": "Serotonin 5-HT2C receptors (5-HT(2C)Rs) are almost exclusively expressed in the CNS, and implicated in disorders such as obesity, depression, and schizophrenia. The present study investigated the mechanisms governing the coupling of the 5-HT(2C)R to the extracellular signal-regulated kinases (ERKs) 1/2, using a Chinese hamster ovary (CHO) cell line stably expressing the receptor at levels comparable to those found in the brain. Using the non-RNA-edited isoform of the 5-HT(2C)R, constitutive ERK1/2 phosphorylation was observed and found to be modulated by full, partial and inverse agonists. Interestingly, agonist-directed trafficking of receptor stimulus was also observed when comparing effects on phosphoinositide accumulation and intracellular Ca2+ elevation to ERK1/2 phosphorylation, whereby the agonists, [+/-]-2,5-dimethoxy-4-iodoamphetamine (DOI) and quipazine, showed reversal of efficacy between the phosphoinositide/Ca2+ pathways, on the one hand, and the ERK1/2 pathway on the other. Subsequent molecular characterization found that 5-HT-stimulated ERK1/2 phosphorylation in this cellular background requires phospholipase D, protein kinase C, and activation of the Raf/MEK/ERK module, but is independent of both receptor- and non-receptor tyrosine kinases, phospholipase C, phosphoinositide 3-kinase, and endocytosis. Our findings underscore the potential for exploiting pathway-selective receptor states in the differential modulation of signaling pathways that play prominent roles in normal and abnormal neuronal signaling.", "title": "Characterization of serotonin 5-HT2C receptor signaling to extracellular signal-regulated kinases 1 and 2." }, { "docid": "17231273", "text": "Energy deficiency and dysfunction of the Na+, K+-ATPase are common consequences of many pathological insults. The nature and mechanism of cell injury induced by impaired Na+, K+-ATPase, however, are not well defined. We used cultured cortical neurons to examine the hypothesis that blocking the Na+, K+-ATPase induces apoptosis by depleting cellular K+ and, concurrently, induces necrotic injury in the same cells by increasing intracellular Ca2+ and Na+. The Na+, K+-ATPase inhibitor ouabain induced concentration-dependent neuronal death. Ouabain triggered transient neuronal cell swelling followed by cell shrinkage, accompanied by intracellular Ca2+ and Na+ increase, K+ decrease, cytochrome c release, caspase-3 activation, and DNA laddering. Electron microscopy revealed the coexistence of ultrastructural features of both apoptosis and necrosis in individual cells. The caspase inhibitor Z-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD-FMK) blocked >50% of ouabain-induced neuronal death. Potassium channel blockers or high K+ medium, but not Ca2+ channel blockade, prevented cytochrome c release, caspase activation, and DNA damage. Blocking of K+, Ca2+, or Na+ channels or high K+ medium each attenuated the ouabain-induced cell death; combined inhibition of K+ channels and Ca2+ or Na+ channels resulted in additional protection. Moreover, coapplication of Z-VAD-FMK and nifedipine produced virtually complete neuroprotection. These results suggest that the neuronal death associated with Na+, K+-pump failure consists of concurrent apoptotic and necrotic components, mediated by intracellular depletion of K+ and accumulation of Ca2+ and Na+, respectively. The ouabain-induced hybrid death may represent a distinct form of cell death related to the brain injury of inadequate energy supply and disrupted ion homeostasis.", "title": "Ionic mechanism of ouabain-induced concurrent apoptosis and necrosis in individual cultured cortical neurons" }, { "docid": "29362104", "text": "The effect of omega-3, omega-6 and omega-9 unsaturated fatty acids (UFAs) on receptor-mediated Ca2+ entry was investigated in a T-cell line (JURKAT) by using anti-CD3 antibodies (OKT3) to induce intracellular Ca2+ [( Ca2+]i) increase and Ca2+ influx. All the UFAs, as well as Ni2+ ions and 12-O-tetradecanoylphorbol 13-acetate, decreased the OKT3-induced sustained [Ca2+]i increase to basal levels. Although non-esterified fatty acids activate protein kinase C (PKC) [McPhail, Clayton & Snyderman (1984) Science 224, 622-624; Murakami, Chan & Routtenberg (1986) J. Biol. Chem. 261, 15424-15429], studies using H-7 and analysis of the PKC-dependent phosphorylation of 19 and 80 kDa marker substrates ruled out the involvement of PKC in UFA-induced inhibition of Ca2+ entry. Flow-cytometry analysis showed that UFAs do not interfere with antibody-receptor binding. BSA (0.2%, w/v) reversed the effect of UFAs after these fatty acids have decreased the OKT3-induced [Ca2+]i increase to basal levels. The relevance of these findings and possible mechanisms for inhibition by UFAs of receptor-mediated Ca2+ influx were discussed.", "title": "Inhibition of receptor-mediated calcium influx in T cells by unsaturated non-esterified fatty acids." }, { "docid": "34582256", "text": "The object of this study was to assess the role of brown adipose tissue (BAT) and the sympathetic nervous system in the rise in heat production associated with endotoxin-induced fever. Oxygen consumption (VO2) was found to be significantly increased (28%) over a 4-h period after two doses of endotoxin (Escherichia coli lipopolysaccharide, 0.3 mg/100 g body wt) given 24 h apart. Injection of a mixed beta-adrenoceptor antagonist (propranolol) reduced VO2 by 14% in endotoxin-treated rats, whereas the selective beta 1- (atenolol) or beta 2- (ICI 118551) antagonists suppressed VO2 by 10%. These drugs did not affect VO2 in control animals. BAT thermogenic activity assessed from measurements of in vitro mitochondrial guanosine 5'-diphosphate (GDP) binding was elevated by 54% in interscapular BAT and by 171% in other BAT depots. Surgical denervation of one lobe of the interscapular depot prevented these responses. Endotoxin failed to stimulate GDP binding in rats fed protein-deficient diets. This may have been because BAT thermogenic activity was already elevated in control rats fed these diets or because endotoxin caused a marked suppression of food intake in the protein-deficient animals. The results indicate that sympathetic activation of BAT is involved in the thermogenic responses to endotoxin and that these can be modified by dietary manipulation.", "title": "Involvement of sympathetic nervous system and brown fat in endotoxin-induced fever in rats." }, { "docid": "10846815", "text": "The actin cortex both facilitates and hinders the exocytosis of secretory granules. How cells consolidate these two opposing roles was not well understood. Here we show that antigen activation of mast cells induces oscillations in Ca(2+) and PtdIns(4,5)P(2) lipid levels that in turn drive cyclic recruitment of N-WASP and cortical actin level oscillations. Experimental and computational analysis argues that vesicle fusion correlates with the observed actin and Ca(2+) level oscillations. A vesicle secretion cycle starts with the capture of vesicles by actin when cortical F-actin levels are high, followed by vesicle passage through the cortex when F-actin levels are low, and vesicle fusion with the plasma membrane when Ca(2+) levels subsequently increase. Thus, cells employ oscillating levels of Ca(2+), PtdIns(4,5)P(2) and cortical F-actin to increase secretion efficiency, explaining how the actin cortex can function as a carrier as well as barrier for vesicle secretion.", "title": "Coordinated oscillations in cortical actin and Ca2+ correlate with cycles of vesicle secretion" }, { "docid": "37964706", "text": "Ca2+ entry through store-operated Ca2+ channels drives the production of the pro-inflammatory molecule leukotriene C4 (LTC4) from mast cells through a pathway involving Ca2+-dependent protein kinase C, mitogen-activated protein kinases ERK1/2, phospholipase A2, and 5-lipoxygenase. Here we examine whether local Ca2+ influx through store-operated Ca2+ release-activated Ca2+ (CRAC) channels in the plasma membrane stimulates this signaling pathway. Manipulating the amplitude and spatial extent of Ca2+ entry by altering chemical and electrical gradients for Ca2+ influx or changing the Ca2+ buffering of the cytoplasm all impacted on protein kinase C and ERK activation, generation of arachidonic acid and LTC4 secretion, with little change in the bulk cytoplasmic Ca2+ rise. Similar bulk cytoplasmic Ca2+ concentrations were achieved when CRAC channels were activated in 0.25 mm external Ca2+ versus 2 mm Ca2+ and 100 nm La3+, an inhibitor of CRAC channels. However, despite similar bulk cytoplasmic Ca2+, protein kinase C activation and LTC4 secretion were larger in 2 mm Ca2+ and La3+ than in 0.25 mm Ca2+, consistent with the central involvement of a subplasmalemmal Ca2+ rise. The nonreceptor tyrosine kinase Syk coupled CRAC channel opening to protein kinase C and ERK activation. Recombinant TRPC3 channels also activated protein kinase C, suggesting that subplasmalemmal Ca2+ rather than a microdomain exclusive to CRAC channels is the trigger. Hence a subplasmalemmal Ca2+ increase in mast cells is highly versatile in that it triggers cytoplasmic responses through generation of intracellular messengers as well as long distance changes through increased secretion of paracrine signals.", "title": "Local Ca2+ influx through Ca2+ release-activated Ca2+ (CRAC) channels stimulates production of an intracellular messenger and an intercellular pro-inflammatory signal." }, { "docid": "9641846", "text": "The ability of progenitor cells to exit the cell cycle is essential for proper embryonic development and homeostasis, but the mechanisms governing cell cycle exit are still not fully understood. Here, we tested the requirement for the retinoblastoma (Rb) protein and its family members p107 and p130 in G0/G1 arrest and differentiation in mammalian cells. We found that Rb family triple knockout (TKO) mouse embryos survive until days 9-11 of gestation. Strikingly, some TKO cells, including in epithelial and neural lineages, are able to exit the cell cycle in G0/G1 and differentiate in teratomas and in culture. This ability of TKO cells to arrest in G0/G1 is associated with the repression of key E2F target genes. Thus, G1 arrest is not always dependent on Rb family members, which illustrates the robustness of cell cycle regulatory networks during differentiation and allows for the identification of candidate pathways to inhibit the expansion of cancer cells with mutations in the Rb pathway.", "title": "G1 arrest and differentiation can occur independently of Rb family function" }, { "docid": "10562341", "text": "The activation of T cells is the fundamental on switch for the adaptive immune system. Ca2+ signaling is essential for T cell activation and starts as initial, short-lived, localized Ca2+ signals. The second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) forms rapidly upon T cell activation and stimulates early Ca2+ signaling. We developed a high-resolution imaging technique using multiple fluorescent Ca2+ indicator dyes to characterize these early signaling events and investigate the channels involved in NAADP-dependent Ca2+ signals. In the first seconds of activation of either primary murine T cells or human Jurkat cells with beads coated with an antibody against CD3, we detected Ca2+ signals with diameters close to the limit of detection and that were close to the activation site at the plasma membrane. In Jurkat cells in which the ryanodine receptor (RyR) was knocked down or in primary T cells from RyR1−/− mice, either these early Ca2+ signals were not detected or the number of signals was markedly reduced. Local Ca2+ signals observed within 20 ms upon microinjection of Jurkat cells with NAADP were also sensitive to RyR knockdown. In contrast, TRPM2 (transient receptor potential channel, subtype melastatin 2), a potential NAADP target channel, was not required for the formation of initial Ca2+ signals in primary T cells. Thus, through our high-resolution imaging method, we characterized early Ca2+ release events in T cells and obtained evidence for the involvement of RyR and NAADP in such signals.", "title": "Frontrunners of T cell activation: Initial, localized Ca2+ signals mediated by NAADP and the type 1 ryanodine receptor" }, { "docid": "12948892", "text": "Evidence has been accumulated that glioblastoma cells release and exploit glutamate for proliferation and migration by autocrine or paracrine loops through Ca2+-permeable AMPA-type glutamate receptors. Here, we show that Ca2+ signaling mediated by AMPA receptor regulates the growth and motility of glioblastoma cells via activation of Akt. Ca2+ supplied through Ca2+-permeable AMPA receptor phosphorylated Akt at Ser-473, thereby facilitating proliferation and mobility. A dominant-negative form of Akt inhibited cell proliferation and migration accelerated by overexpression of Ca2+-permeable AMPA receptor. In contrast, introduction of a constitutively active form of Akt rescued tumor cells from apoptosis induced by the conversion of Ca2+-permeable AMPA receptor to Ca2+-impermeable receptors by the delivery of GluR2 cDNA. Therefore, Akt functions as downstream effectors for Ca2+-signaling mediated by AMPA receptor in glioblastoma cells. The activation of the glutamate-AMPA receptor-Akt pathway may contribute to the high degree of anaplasia and invasive growth of human glioblastoma. This novel pathway might give an alternative therapeutic target.", "title": "Ca2+-permeable AMPA receptors regulate growth of human glioblastoma via Akt activation." }, { "docid": "30303335", "text": "Excitation-transcription coupling, linking stimulation at the cell surface to changes in nuclear gene expression, is conserved throughout eukaryotes. How closely related coexpressed transcription factors are differentially activated remains unclear. Here, we show that two Ca2+-dependent transcription factor isoforms, NFAT1 and NFAT4, require distinct sub-cellular InsP3 and Ca2+ signals for physiologically sustained activation. NFAT1 is stimulated by sub-plasmalemmal Ca2+ microdomains, whereas NFAT4 additionally requires Ca2+ mobilization from the inner nuclear envelope by nuclear InsP3 receptors. NFAT1 is rephosphorylated (deactivated) more slowly than NFAT4 in both cytoplasm and nucleus, enabling a more prolonged activation phase. Oscillations in cytoplasmic Ca2+, long considered the physiological form of Ca2+ signaling, play no role in activating either NFAT protein. Instead, effective sustained physiological activation of NFAT4 is tightly linked to oscillations in nuclear Ca2+. Our results show how gene expression can be controlled by coincident yet geographically distinct Ca2+ signals, generated by a freely diffusible InsP3 message.", "title": "Control of NFAT Isoform Activation and NFAT-Dependent Gene Expression through Two Coincident and Spatially Segregated Intracellular Ca2+ Signals" }, { "docid": "7869794", "text": "Ca2+ messages are broadly important in cellular signal transduction. In immune cells, Ca2+ signaling is an essential step in many forms of activation. Neutrophil-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) is one form of leukocyte activation that plays an important role in tumor cell killing in vitro and in patient care. Using fluorescence methodologies, we found that neutrophils exhibit Ca2+ signals during ADCC directed against breast fibrosarcoma cells. Importantly, these signals were localized to Ca2+ microdomains at the neutrophil-to-tumor cell interface where they display dynamic features such as movement, fusion, and fission. These signals were blocked by the intracellular Ca2+ buffer BAPTA. At the neutrophil–tumor cell synapse, the neutrophil’s cytoplasm was enriched in STIM1, a crucial mediator of Ca2+ signaling, whereas the Ca2+-binding proteins calbindin and parvalbumin were not affected. Our findings suggest that Ca2+ microdomains are due to an active signaling process. As Ca2+ signals within neutrophils were necessary for specific tumor cell apoptosis, a central role of microdomains in leukocyte-mediated tumor cell destruction is indicated.", "title": "Calicum microdomains form within neutrophils at the neutrophil–tumor cell synapse: role in antibody-dependent target cell apoptosis" } ]

[ { "docid": "2014909", "text": "Myeloid-derived suppressor cells (MDSCs) play critical roles in primary and metastatic cancer progression. MDSC regulation is widely variable even among patients harbouring the same type of malignancy, and the mechanisms governing such heterogeneity are largely unknown. Here, integrating human tumour genomics and syngeneic mammary tumour models, we demonstrate that mTOR signalling in cancer cells dictates a mammary tumour's ability to stimulate MDSC accumulation through regulating G-CSF. Inhibiting this pathway or its activators (for example, FGFR) impairs tumour progression, which is partially rescued by restoring MDSCs or G-CSF. Tumour-initiating cells (TICs) exhibit elevated G-CSF. MDSCs reciprocally increase TIC frequency through activating Notch in tumour cells, forming a feedforward loop. Analyses of primary breast cancers and patient-derived xenografts corroborate these mechanisms in patients. These findings establish a non-canonical oncogenic role of mTOR signalling in recruiting pro-tumorigenic MDSCs and show how defined cancer subsets may evolve to promote and depend on a distinct immune microenvironment.", "title": "Oncogenic mTOR signaling recruits myeloid-derived suppressor cells to promote tumor initiation" } ]

[ { "docid": "188911", "text": "Antigen-presenting, major histocompatibility complex (MHC) class II-rich dendritic cells are known to arise from bone marrow. However, marrow lacks mature dendritic cells, and substantial numbers of proliferating less-mature cells have yet to be identified. The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II-negative precursors in marrow. A key step is to remove the majority of nonadherent, newly formed granulocytes by gentle washes during the first 2-4 d of culture. This leaves behind proliferating clusters that are loosely attached to a more firmly adherent \"stroma. \" At days 4-6 the clusters can be dislodged, isolated by 1-g sedimentation, and upon reculture, large numbers of dendritic cells are released. The latter are readily identified on the basis of their distinct cell shape, ultrastructure, and repertoire of antigens, as detected with a panel of monoclonal antibodies. The dendritic cells express high levels of MHC class II products and act as powerful accessory cells for initiating the mixed leukocyte reaction. Neither the clusters nor mature dendritic cells are generated if macrophage colony-stimulating factor rather than granulocyte/macrophage colony-stimulating factor (GM-CSF) is applied. Therefore, GM-CSF generates all three lineages of myeloid cells (granulocytes, macrophages, and dendritic cells). Since > 5 x 10(6) dendritic cells develop in 1 wk from precursors within the large hind limb bones of a single animal, marrow progenitors can act as a major source of dendritic cells. This feature should prove useful for future molecular and clinical studies of this otherwise trace cell type.", "title": "Generation of large numbers of dendritic cells from mouse bone marrow cultures supplemented with granulocyte/macrophage colony-stimulating factor" }, { "docid": "44562221", "text": "Endogenous glucocorticoids (GC) play an important role in the termination of the inflammatory response following infection and tissue injury. However, recent findings indicate that stress can impair the anti-inflammatory capacities of these hormones. Lipopolysaccharide (LPS)-stimulated splenocytes of mice that were repeatedly subjected to social disruption (SDR) stress were less sensitive to the immunosuppressive effects of corticosterone (CORT) as demonstrated by an increased production of pro-inflammatory cytokines and enhanced cell survival. Myeloid cells expressing the marker CD11b were shown to play a key role in this process. Here we investigated the role of the bone marrow as a potential source of the GC-insensitive cells. The study revealed that LPS-stimulated bone marrow cells, in the absence of experimental stress, were virtually GC-resistant and retained high levels of cell viability after treatment with CORT. Recurrent exposure to the acute stressor over a period of 2, 4 or 6 days led to an increase in the GC sensitivity of the bone marrow cells. This increase in GC sensitivity was associated with enhanced mRNA expression of granulocyte-macrophage colony-stimulating factor (GM-CSF), an increase in the number of myeloid progenitors, and a decrease in the proportion of mature CD11b+ cells. The changes in the cellular composition of the bone marrow were accompanied by an increase in splenic CD11b+ cell numbers. Simultaneous assessment of the GC sensitivity in bone marrow and spleen revealed a significant negative correlation between both tissues suggesting that social stress causes the redistribution of GC-insensitive myeloid cells from the bone marrow to the spleen.", "title": "Tissue-specific alterations in the glucocorticoid sensitivity of immune cells following repeated social defeat in mice" }, { "docid": "42465769", "text": "Adipocytes are part of hematopoietic microenvironment, even though up to now in humans, their role in hematopoiesis is still questioned. We have previously shown that accumulation of fat cells in femoral bone marrow (BM) coincides with increased expression of neuropilin-1 (NP-1), while it is weakly expressed in hematopoietic iliac crest BM. Starting from this observation, we postulated that adipocytes might exert a negative effect on hematopoiesis mediated through NP-1. To test this hypothesis, we set up BM adipocytes differentiated into fibroblast-like fat cells (FLFC), which share the major characteristics of primitive unilocular fat cells, as an experimental model. As expected, FLFCs constitutively produced macrophage colony stimulating factor and induced CD34(+) differentiation into macrophages independently of cell-to-cell contact. By contrast, granulopoiesis was hampered by cell-to-cell contact but could be restored in transwell culture conditions, together with granulocyte colony stimulating factor production. Both functions were also recovered when FLFCs cultured in contact with CD34(+) cells were treated with an antibody neutralizing NP-1, which proved its critical implication in contact inhibition. An inflammatory cytokine such as interleukin-1 beta or dexamethasone modulates FLFC properties to restore granulopoiesis. Our data provide the first evidence that primary adipocytes exert regulatory functions during hematopoiesis that might be implicated in some pathological processes. Disclosure of potential conflicts of interest is found at the end of this article.", "title": "Human bone marrow adipocytes block granulopoiesis through neuropilin-1-induced granulocyte colony-stimulating factor inhibition." }, { "docid": "24612804", "text": "IL-17 is a novel, CD4+ T cell-restricted cytokine. In vivo, it stimulates hematopoiesis and causes neutrophilia consisting of mature granulocytes. In this study, we show that IL-17-mediated granulopoiesis requires G-CSF release and the presence or induction of the transmembrane form of stem cell factor (SCF) for optimal granulopoiesis. However, IL-17 also protects mice from G-CSF neutralization-induced neutropenia. G-CSF neutralization completely reversed IL-17-induced BM progenitor expansion, whereas splenic CFU-GM/CFU-granulocyte-erythrocyte-megakaryocyte-monocyte was only reduced by 50% in both Sl/Sld and littermate control mice. Thus, there remained a significant SCF/G-CSF-independent effect of IL-17 on splenic granulopoiesis, resulting in a preservation of mature circulating granulocytes. IL-17 is a cytokine that potentially interconnects lymphocytic and myeloid host defense and may have potential for therapeutic development.", "title": "Requirement of endogenous stem cell factor and granulocyte-colony-stimulating factor for IL-17-mediated granulopoiesis." }, { "docid": "19510470", "text": "Cancer stem cells have been proposed to be important for initiation, maintenance and recurrence of various malignancies, including acute myeloid leukemia (AML). We have previously reported that CD34+CD38− human primary AML stem cells residing in the endosteal region of the bone marrow are relatively chemotherapy resistant. Using a NOD/SCID/IL2rγnull mouse model of human AML, we now show that the AML stem cells in the endosteal region are cell cycle quiescent and that these stem cells can be induced to enter the cell cycle by treatment with granulocyte colony-stimulating factor (G-CSF). In combination with cell cycle-dependent chemotherapy, G-CSF treatment significantly enhances induction of apoptosis and elimination of human primary AML stem cells in vivo. The combination therapy leads to significantly increased survival of secondary recipients after transplantation of leukemia cells compared with chemotherapy alone.", "title": "Induction of cell cycle entry eliminates human leukemia stem cells in a mouse model of AML" }, { "docid": "5774746", "text": "S100A4 is implicated in metastasis and chronic inflammation, but its function remains uncertain. Here we establish an S100A4-dependent link between inflammation and metastatic tumor progression. We found that the acute-phase response proteins serum amyloid A (SAA) 1 and SAA3 are transcriptional targets of S100A4 via Toll-like receptor 4 (TLR4)/nuclear factor-κB signaling. SAA proteins stimulated the transcription of RANTES (regulated upon activation normal T-cell expressed and presumably secreted), G-CSF (granulocyte-colony-stimulating factor) and MMP2 (matrix metalloproteinase 2), MMP3, MMP9 and MMP13. We have also shown for the first time that SAA stimulate their own transcription as well as that of proinflammatory S100A8 and S100A9 proteins. Moreover, they strongly enhanced tumor cell adhesion to fibronectin, and stimulated migration and invasion of human and mouse tumor cells. Intravenously injected S100A4 protein induced expression of SAA proteins and cytokines in an organ-specific manner. In a breast cancer animal model, ectopic expression of SAA1 or SAA3 in tumor cells potently promoted widespread metastasis formation accompanied by a massive infiltration of immune cells. Furthermore, coordinate expression of S100A4 and SAA in tumor samples from colorectal carcinoma patients significantly correlated with reduced overall survival. These data show that SAA proteins are effectors for the metastasis-promoting functions of S100A4, and serve as a link between inflammation and tumor progression.", "title": "A link between inflammation and metastasis: serum amyloid A1 and A3 induce metastasis, and are targets of metastasis-inducing S100A4" }, { "docid": "8764879", "text": "Leukemias and other cancers possess self-renewing stem cells that help to maintain the cancer. Cancer stem cell eradication is thought to be crucial for successful anticancer therapy. Using an acute myeloid leukemia (AML) model induced by the leukemia-associated monocytic leukemia zinc finger (MOZ)-TIF2 fusion protein, we show here that AML can be cured by the ablation of leukemia stem cells. The MOZ fusion proteins MOZ-TIF2 and MOZ-CBP interacted with the transcription factor PU.1 to stimulate the expression of macrophage colony–stimulating factor receptor (CSF1R, also known as M-CSFR, c-FMS or CD115). Studies using PU.1-deficient mice showed that PU.1 is essential for the ability of MOZ-TIF2 to establish and maintain AML stem cells. Cells expressing high amounts of CSF1R (CSF1Rhigh cells), but not those expressing low amounts of CSF1R (CSF1Rlow cells), showed potent leukemia-initiating activity. Using transgenic mice expressing a drug-inducible suicide gene controlled by the CSF1R promoter, we cured AML by ablation of CSF1Rhigh cells. Moreover, induction of AML was suppressed in CSF1R-deficient mice and CSF1R inhibitors slowed the progression of MOZ-TIF2–induced leukemia. Thus, in this subtype of AML, leukemia stem cells are contained within the CSF1Rhigh cell population, and we suggest that targeting of PU.1-mediated upregulation of CSF1R expression might be a useful therapeutic approach.", "title": "PU.1-mediated upregulation of CSF1R is crucial for leukemia stem cell potential induced by MOZ-TIF2" }, { "docid": "15248287", "text": "Neutrophil apoptosis is a highly regulated process essential for inflammation resolution, the molecular mechanisms of which are only partially elucidated. In this study, we describe a survival pathway controlled by proliferating cell nuclear antigen (PCNA), a nuclear factor involved in DNA replication and repairing of proliferating cells. We show that mature neutrophils, despite their inability to proliferate, express high levels of PCNA exclusively in their cytosol and constitutively associated with procaspases, presumably to prevent their activation. Notably, cytosolic PCNA abundance decreased during apoptosis, and increased during in vitro and in vivo exposure to the survival factor granulocyte colony-stimulating factor (G-CSF). Peptides derived from the cyclin-dependent kinase inhibitor p21, which compete with procaspases to bind PCNA, triggered neutrophil apoptosis thus demonstrating that specific modification of PCNA protein interactions affects neutrophil survival. Furthermore, PCNA overexpression rendered neutrophil-differentiated PLB985 myeloid cells significantly more resistant to TNF-related apoptosis-inducing ligand- or gliotoxin-induced apoptosis. Conversely, a decrease in PCNA expression after PCNA small interfering RNA transfection sensitized these cells to apoptosis. Finally, a mutation in the PCNA interdomain-connecting loop, the binding site for many partners, significantly decreased the PCNA-mediated antiapoptotic effect. These results identify PCNA as a regulator of neutrophil lifespan, thereby highlighting a novel target to potentially modulate pathological inflammation.", "title": "Proliferating cell nuclear antigen acts as a cytoplasmic platform controlling human neutrophil survival" }, { "docid": "38886345", "text": "BACKGROUND JX-594 is a targeted oncolytic poxvirus designed to selectively replicate in and destroy cancer cells with cell-cycle abnormalities and epidermal growth factor receptor (EGFR)-ras pathway activation. Direct oncolysis plus granulocyte-macrophage colony-stimulating factor (GM-CSF) expression also stimulates shutdown of tumour vasculature and antitumoral immunity. We aimed to assess intratumoral injection of JX-594 in patients with refractory primary or metastatic liver cancer. \n METHODS Between Jan 4, 2006, and July 4, 2007, 14 patients with histologically confirmed refractory primary or metastatic liver tumours (up to 10.9 cm total diameter) that were amenable to image-guided intratumoral injections were enrolled into this non-comparative, open-label, phase I dose-escalation trial (standard 3x3 design; two to six patients for each dose with 12-18 estimated total patients). Patients received one of four doses of intratumoral JX-594 (10(8) plaque-forming units [pfu], 3x10(8) pfu, 10(9) pfu, or 3x10(9) pfu) every 3 weeks at Dong-A University Hospital (Busan, South Korea). Patients were monitored after treatment for at least 48 h in hospital and for at least 4 weeks as out-patients. Adverse event-monitoring according to the National Cancer Institute Common Toxicity Criteria (version 3) and standard laboratory toxicity grading for haematology, liver and renal function, coagulation studies, serum chemistry, and urinalysis were done. The primary aims were to ascertain the maximum-tolerated dose (MTD) and safety of JX-594 treatment. Data were also collected on pharmacokinetics, pharmacodynamics, and efficacy. Analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00629759. \n FINDINGS Of 22 patients with liver tumours who were assessed for eligibility, eight patients did not meet inclusion criteria. Therefore, 14 patients, including those with hepatocellular, colorectal, melanoma, and lung cancer, were enrolled. Patients were heavily pretreated (5.6 previous treatments, SD 2.8, range 2.0-12.0) and had large tumours (7.0 cm diameter, SD 2.7, range 1.8-10.9). Patients received a mean of 3.4 (SD 2.2, range 1.0-8.0) cycles of JX-594. All patients were evaluable for toxicity. All patients experienced grade I-III flu-like symptoms, and four had transient grade I-III dose-related thrombocytopenia. Grade III hyperbilirubinaemia was dose-limiting in both patients at the highest dose; the MTD was therefore 1x10(9) pfu. JX-594 replication-dependent dissemination in blood was shown, with resultant infection of non-injected tumour sites. GM-CSF expression resulted in grade I-III increases in neutrophil counts in four of six patients at the MTD. Tumour responses were shown in injected and non-injected tumours. Ten patients were radiographically evaluable for objective responses; non-evaluable patients had contraindications to contrast medium (n=2) or no post-treatment scans (n=2). According to Response Evaluation Criteria in Solid Tumors (RECIST), three patients had partial response, six had stable disease, and one had progressive disease. \n INTERPRETATION Intratumoral injection of JX-594 into primary or metastatic liver tumours was generally well-tolerated. Direct hyperbilirubinaemia was the dose-limiting toxicity. Safety was acceptable in the context of JX-594 replication, GM-CSF expression, systemic dissemination, and JX-594 had anti-tumoral effects against several refractory carcinomas. Phase II trials are now underway.", "title": "Use of a targeted oncolytic poxvirus, JX-594, in patients with refractory primary or metastatic liver cancer: a phase I trial." }, { "docid": "9878167", "text": "Neutrophil extracellular traps (NETs) represent extracellular structures able to bind and kill microorganisms. It is believed that they are generated by neutrophils undergoing cell death, allowing these dying or dead cells to kill microbes. We show that, following priming with granulocyte/macrophage colony-stimulating factor (GM-CSF) and subsequent short-term toll-like receptor 4 (TLR4) or complement factor 5a (C5a) receptor stimulation, viable neutrophils are able to generate NETs. Strikingly, NETs formed by living cells contain mitochondrial, but no nuclear, DNA. Pharmacological or genetic approaches to block reactive oxygen species (ROS) production suggested that NET formation is ROS dependent. Moreover, neutrophil populations stimulated with GM-CSF and C5a showed increased survival compared with resting neutrophils, which did not generate NETs. In conclusion, mitochondrial DNA release by neutrophils and NET formation do not require neutrophil death and do also not limit the lifespan of these cells.", "title": "Viable neutrophils release mitochondrial DNA to form neutrophil extracellular traps" }, { "docid": "5483793", "text": "Antigen-specific CD8+ T-cell tolerance, induced by myeloid-derived suppressor cells (MDSCs), is one of the main mechanisms of tumor escape. Using in vivo models, we show here that MDSCs directly disrupt the binding of specific peptide–major histocompatibility complex (pMHC) dimers to CD8-expressing T cells through nitration of tyrosines in a T-cell receptor (TCR)-CD8 complex. This process makes CD8-expressing T cells unable to bind pMHC and to respond to the specific peptide, although they retain their ability to respond to nonspecific stimulation. Nitration of TCR-CD8 is induced by MDSCs through hyperproduction of reactive oxygen species and peroxynitrite during direct cell-cell contact. Molecular modeling suggests specific sites of nitration that might affect the conformational flexibility of TCR-CD8 and its interaction with pMHC. These data identify a previously unknown mechanism of T-cell tolerance in cancer that is also pertinent to many pathological conditions associated with accumulation of MDSCs.", "title": "Altered recognition of antigen is a mechanism of CD8+ T cell tolerance in cancer" }, { "docid": "2030623", "text": "Myeloid-derived suppressor cells (MDSC) promote tumor growth by inhibiting T-cell immunity and promoting malignant cell proliferation and migration. The therapeutic potential of blocking MDSC in tumors has been limited by their heterogeneity, plasticity, and resistance to various chemotherapy agents. Recent studies have highlighted the role of energy metabolic pathways in the differentiation and function of immune cells; however, the metabolic characteristics regulating MDSC remain unclear. We aimed to determine the energy metabolic pathway(s) used by MDSC, establish its impact on their immunosuppressive function, and test whether its inhibition blocks MDSC and enhances antitumor therapies. Using several murine tumor models, we found that tumor-infiltrating MDSC (T-MDSC) increased fatty acid uptake and activated fatty acid oxidation (FAO). This was accompanied by an increased mitochondrial mass, upregulation of key FAO enzymes, and increased oxygen consumption rate. Pharmacologic inhibition of FAO blocked immune inhibitory pathways and functions in T-MDSC and decreased their production of inhibitory cytokines. FAO inhibition alone significantly delayed tumor growth in a T-cell-dependent manner and enhanced the antitumor effect of adoptive T-cell therapy. Furthermore, FAO inhibition combined with low-dose chemotherapy completely inhibited T-MDSC immunosuppressive effects and induced a significant antitumor effect. Interestingly, a similar increase in fatty acid uptake and expression of FAO-related enzymes was found in human MDSC in peripheral blood and tumors. These results support the possibility of testing FAO inhibition as a novel approach to block MDSC and enhance various cancer therapies.", "title": "Inhibition of fatty acid oxidation modulates immunosuppressive functions of myeloid-derived suppressor cells and enhances cancer therapies" }, { "docid": "12827098", "text": "Despite accumulating evidence suggesting local self-maintenance of tissue macrophages in the steady state, the dogma remains that tissue macrophages derive from monocytes. Using parabiosis and fate-mapping approaches, we confirmed that monocytes do not show significant contribution to tissue macrophages in the steady state. Similarly, we found that after depletion of lung macrophages, the majority of repopulation occurred by stochastic cellular proliferation in situ in a macrophage colony-stimulating factor (M-Csf)- and granulocyte macrophage (GM)-CSF-dependent manner but independently of interleukin-4. We also found that after bone marrow transplantation, host macrophages retained the capacity to expand when the development of donor macrophages was compromised. Expansion of host macrophages was functional and prevented the development of alveolar proteinosis in mice transplanted with GM-Csf-receptor-deficient progenitors. Collectively, these results indicate that tissue-resident macrophages and circulating monocytes should be classified as mononuclear phagocyte lineages that are independently maintained in the steady state.", "title": "Tissue-resident macrophages self-maintain locally throughout adult life with minimal contribution from circulating monocytes." }, { "docid": "19800147", "text": "Exosomes are emerging mediators of intercellular communication; whether the release of exosomes has an effect on the exosome donor cells in addition to the recipient cells has not been investigated to any extent. Here, we examine different exosomal miRNA expression profiles in primary mouse colon tumour, liver metastasis of colon cancer and naive colon tissues. In more advanced disease, higher levels of tumour suppressor miRNAs are encapsulated in the exosomes. miR-193a interacts with major vault protein (MVP). Knockout of MVP leads to miR-193a accumulation in the exosomal donor cells instead of exosomes, inhibiting tumour progression. Furthermore, miR-193a causes cell cycle G1 arrest and cell proliferation repression through targeting of Caprin1, which upregulates Ccnd2 and c-Myc. Human colon cancer patients with more advanced disease show higher levels of circulating exosomal miR-193a. In summary, our data demonstrate that MVP-mediated selective sorting of tumour suppressor miRNA into exosomes promotes tumour progression.", "title": "MVP-mediated exosomal sorting of miR-193a promotes colon cancer progression" }, { "docid": "11903247", "text": "Multiple cellular stressors, including activation of the tumour suppressor p53, can stimulate autophagy. Here we show that deletion, depletion or inhibition of p53 can induce autophagy in human, mouse and nematode cells subjected to knockout, knockdown or pharmacological inhibition of p53. Enhanced autophagy improved the survival of p53-deficient cancer cells under conditions of hypoxia and nutrient depletion, allowing them to maintain high ATP levels. Inhibition of p53 led to autophagy in enucleated cells, and cytoplasmic, not nuclear, p53 was able to repress the enhanced autophagy of p53−/− cells. Many different inducers of autophagy (for example, starvation, rapamycin and toxins affecting the endoplasmic reticulum) stimulated proteasome-mediated degradation of p53 through a pathway relying on the E3 ubiquitin ligase HDM2. Inhibition of p53 degradation prevented the activation of autophagy in several cell lines, in response to several distinct stimuli. These results provide evidence of a key signalling pathway that links autophagy to the cancer-associated dysregulation of p53.", "title": "Regulation of autophagy by cytoplasmic p53" }, { "docid": "24294572", "text": "The PI3K signaling pathway regulates cell growth and movement and is heavily mutated in cancer. Class I PI3Ks synthesize the lipid messenger PI(3,4,5)P3. PI(3,4,5)P3 can be dephosphorylated by 3- or 5-phosphatases, the latter producing PI(3,4)P2. The PTEN tumor suppressor is thought to function primarily as a PI(3,4,5)P3 3-phosphatase, limiting activation of this pathway. Here we show that PTEN also functions as a PI(3,4)P2 3-phosphatase, both in vitro and in vivo. PTEN is a major PI(3,4)P2 phosphatase in Mcf10a cytosol, and loss of PTEN and INPP4B, a known PI(3,4)P2 4-phosphatase, leads to synergistic accumulation of PI(3,4)P2, which correlated with increased invadopodia in epidermal growth factor (EGF)-stimulated cells. PTEN deletion increased PI(3,4)P2 levels in a mouse model of prostate cancer, and it inversely correlated with PI(3,4)P2 levels across several EGF-stimulated prostate and breast cancer lines. These results point to a role for PI(3,4)P2 in the phenotype caused by loss-of-function mutations or deletions in PTEN.", "title": "PTEN Regulates PI(3,4)P2 Signaling Downstream of Class I PI3K" }, { "docid": "5836", "text": "Myelodysplastic syndromes (MDS) are age-dependent stem cell malignancies that share biological features of activated adaptive immune response and ineffective hematopoiesis. Here we report that myeloid-derived suppressor cells (MDSC), which are classically linked to immunosuppression, inflammation, and cancer, were markedly expanded in the bone marrow of MDS patients and played a pathogenetic role in the development of ineffective hematopoiesis. These clonally distinct MDSC overproduce hematopoietic suppressive cytokines and function as potent apoptotic effectors targeting autologous hematopoietic progenitors. Using multiple transfected cell models, we found that MDSC expansion is driven by the interaction of the proinflammatory molecule S100A9 with CD33. These 2 proteins formed a functional ligand/receptor pair that recruited components to CD33’s immunoreceptor tyrosine-based inhibition motif (ITIM), inducing secretion of the suppressive cytokines IL-10 and TGF-β by immature myeloid cells. S100A9 transgenic mice displayed bone marrow accumulation of MDSC accompanied by development of progressive multilineage cytopenias and cytological dysplasia. Importantly, early forced maturation of MDSC by either all-trans-retinoic acid treatment or active immunoreceptor tyrosine-based activation motif–bearing (ITAM-bearing) adapter protein (DAP12) interruption of CD33 signaling rescued the hematologic phenotype. These findings indicate that primary bone marrow expansion of MDSC driven by the S100A9/CD33 pathway perturbs hematopoiesis and contributes to the development of MDS.", "title": "Induction of myelodysplasia by myeloid-derived suppressor cells." }, { "docid": "21498497", "text": "Leprosy enables investigation of mechanisms by which the innate immune system contributes to host defense against infection, because in one form, the disease progresses, and in the other, the infection is limited. We report that Toll-like receptor (TLR) activation of human monocytes induces rapid differentiation into two distinct subsets: DC-SIGN+ CD16+ macrophages and CD1b+ DC-SIGN− dendritic cells. DC-SIGN+ phagocytic macrophages were expanded by TLR-mediated upregulation of interleukin (IL)-15 and IL-15 receptor. CD1b+ dendritic cells were expanded by TLR-mediated upregulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) and its receptor, promoted T cell activation and secreted proinflammatory cytokines. Whereas DC-SIGN+ macrophages were detected in lesions and after TLR activation in all leprosy patients, CD1b+ dendritic cells were not detected in lesions or after TLR activation of peripheral monocytes in individuals with the progressive lepromatous form, except during reversal reactions in which bacilli were cleared by T helper type 1 (TH1) responses. In tuberculoid lepromatous lesions, DC-SIGN+ cells were positive for macrophage markers, but negative for dendritic cell markers. Thus, TLR-induced differentiation of monocytes into either macrophages or dendritic cells seems to crucially influence effective host defenses in human infectious disease.", "title": "TLR activation triggers the rapid differentiation of monocytes into macrophages and dendritic cells" }, { "docid": "25726838", "text": "The role of immune responses in tumor development is a central issue for tumor biology and immunology. IL-17 is an important cytokine for inflammatory and autoimmune diseases. Although IL-17-producing cells are detected in cancer patients and tumor-bearing mice, the role of IL-17 in tumor development is controversial, and mechanisms remain to be fully elucidated. In the current study, we found that the development of tumors was inhibited in IL-17R-deficient mice. A defect in IFN-gammaR increased tumor growth, whereas tumor growth was inhibited in mice that were deficient in both IL-17R and IFN-gammaR compared with wild-type animals. Further experiments showed that neutralization of IL-17 by Abs inhibited tumor growth in wild-type mice, whereas systemic administration of IL-17 promoted tumor growth. The IL-17R deficiency increased CD8 T cell infiltration, whereas it reduced the infiltration of myeloid-derived suppressor cells (MDSCs) in tumors. In contrast, administration of IL-17 inhibited CD8 T cell infiltration and increased MDSCs in tumors. Further analysis indicated that IL-17 was required for the development and tumor-promoting activity of MDSCs in tumor-bearing mice. These data demonstrate that IL-17-mediated responses promote tumor development through the induction of tumor-promoting microenvironments at tumor sites. IL-17-mediated regulation of MDSCs is a primary mechanism for its tumor-promoting effects. The study provides novel insights into the role of IL-17 in tumor development and has major implications for targeting IL-17 in treatment of tumors.", "title": "IL-17 promotes tumor development through the induction of tumor promoting microenvironments at tumor sites and myeloid-derived suppressor cells." } ]

[ { "docid": "6944800", "text": "Cancers develop in complex tissue environments, which they depend on for sustained growth, invasion and metastasis. Unlike tumor cells, stromal cell types within the tumor microenvironment (TME) are genetically stable and thus represent an attractive therapeutic target with reduced risk of resistance and tumor recurrence. However, specifically disrupting the pro-tumorigenic TME is a challenging undertaking, as the TME has diverse capacities to induce both beneficial and adverse consequences for tumorigenesis. Furthermore, many studies have shown that the microenvironment is capable of normalizing tumor cells, suggesting that re-education of stromal cells, rather than targeted ablation per se, may be an effective strategy for treating cancer. Here we discuss the paradoxical roles of the TME during specific stages of cancer progression and metastasis, as well as recent therapeutic attempts to re-educate stromal cells within the TME to have anti-tumorigenic effects.", "title": "Microenvironmental regulation of tumor progression and metastasis" } ]

[ { "docid": "952111", "text": "Cancer associated fibroblasts (CAFs) is one of the most crucial components of the tumor microenvironment which promotes the growth and invasion of cancer cells by various mechanisms. CAFs demonstrate a high degree of heterogeneity due to their various origins; however, many distinct morphological features and physiological functions of CAFs have been identified. It is becoming clear that the crosstalk between the cancer cells and the CAFs plays a key role in the progression of cancer, and understanding this mutual relationship would eventually enable us to treat cancer patients by targeting CAFs. In this review, we will discuss the latest findings on the role of CAFs in tumorigenesis and metastasis as well as potential therapeutic implication of CAFs.", "title": "Cancer associated fibroblasts (CAFs) in tumor microenvironment." }, { "docid": "32742683", "text": "Among cells present in the tumor microenvironment, activated fibroblasts termed cancer-associated fibroblasts (CAFs), play a critical role in the complex process of tumor-stroma interaction. CAFs, one of the prominent stromal cell populations in most types of human carcinomas, have been involved in tumor growth, angiogenesis, cancer stemness, extracellular matrix remodeling, tissue invasion, metastasis, and even chemoresistance. During the past decade, these activated tumor-associated fibroblasts have also been involved in the modulation of the anti-tumor immune response on various levels. In this review, we describe our current understanding of how CAFs accomplish this task as well as their potential therapeutic implications.", "title": "Alteration of the Antitumor Immune Response by Cancer-Associated Fibroblasts" }, { "docid": "8702697", "text": "AIMS Tumor microenvironment is a strong determinant for the acquisition of metastatic potential of cancer cells. We have recently demonstrated that cancer-associated fibroblasts (CAFs) elicit a redox-dependent epithelial-mesenchymal transition (EMT) in prostate cancer (PCa) cells, driven by cycloxygenase-2/hypoxia-inducible factor-1 (HIF-1)/nuclear factor-κB pathway and enhancing tumor aggressiveness. Here, we investigated the involvement of microRNAs (miRNAs) in tumor-stroma interplay to identify possible tools to counteract oxidative stress and metastasis dissemination. \n RESULTS We found that miR-205 is the most downmodulated miRNA in PCa cells upon CAF stimulation, due to direct transcriptional repression by HIF-1, a known redox-sensitive transcription factor. Rescue experiments demonstrated that ectopic miR-205 overexpression in PCa cells counteracts CAF-induced EMT, thus impairing enhancement of cell invasion, acquisition of stem cell traits, tumorigenicity, and metastatic dissemination. In addition, miR-205 blocks tumor-driven activation of surrounding fibroblasts by reducing pro-inflammatory cytokine secretion. INNOVATION Overall, such findings suggest miR-205 as a brake against PCa metastasis by blocking both the afferent and efferent arms of the circuit between tumor cells and associated fibroblasts, thus interrupting the pro-oxidant and pro-inflammatory circuitries engaged by reactive stroma. \n CONCLUSION The evidence that miR-205 replacement in PCa cells is able not only to prevent but also to revert the oxidative/pro-inflammatory axis leading to EMT induced by CAFs sets the rationale for developing miRNA-based approaches to prevent and treat metastatic disease.", "title": "miR-205 hinders the malignant interplay between prostate cancer cells and associated fibroblasts." }, { "docid": "10812605", "text": "Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.", "title": "Fibroblast heterogeneity in the cancer wound" }, { "docid": "35993767", "text": "Fibroblasts are rich in the surrounding microenvironment of hepatocellular carcinoma (HCC) because most HCCs occur in fibrotic or cirrhotic livers. However, the role of cancer-associated fibroblasts (CAFs) in HCC metastasis remains obscure. Here, we reported that CAFs promote the migration and invasion of HCC cells in vitro and facilitate the HCC metastasis to the bone, brain and lung in NOD/SCID mice. The RayBio human chemokine antibody array revealed that CAFs secret higher levels of CCL2, CCL5, CCL7 and CXCL16 than peri-tumor fibroblasts. CCL2 and CCL5 increase the migration but not the invasion of HCC cells, while CCL7 and CXCL16 promote both migration and invasion of HCC cells. Moreover, CCL2 and CCL5 stimulate the activation of the hedgehog (Hh) pathway, while CCL7 and CXCL16 enhance the activity of the transforming growth factor-β (TGF-β) pathway in HCC cells. The neutralizing antibodies of chemokines notably attenuate the effect of CAFs on HCC metastasis and compromised the activation of Hh and TGF-β pathways in HCC cells. In summary, CAF-secreted CCL2, CCL5, CCL7 and CXCL16 promote HCC metastasis through the coordinate activation of Hh and TGF-β pathways in HCC cells.", "title": "Cancer-associated fibroblasts promote hepatocellular carcinoma metastasis through chemokine-activated hedgehog and TGF-β pathways." }, { "docid": "9648896", "text": "Lung cancer is the leading cause of cancer-related mortality in humans worldwide. Moreover, the overall 5-year survival rate is only 15%. Pathologically almost 80% of all lung cancer cases are non-small cell lung cancer (NSCLC). Cancer-associated fibroblasts (CAFs) have been found to exist in a large number of NSCLCs. CAFs have been proven to promote tumor progression, metastasis and resistance to therapy through paracrine effects in most solid tumors. In the present study, firstly we isolated CAFs from patient tissues and demonstrated that they promoted cell proliferation and chemoresistance to cisplatin in the lung cancer cell lines A549 and 95D in a paracrine manner. Secondly, using ELISA and quantative PCR, we found that a higher amount of stromal cell-derived factor 1 (SDF-1) existed in the CAFs rather than that observed in the normal fibroblasts (NFs). Thirdly, we detected that SDF-1 facilitated lung cancer cell proliferation and drug resistance via the CXCR4-mediated signaling pathway which involved NF-κB and Bcl-xL. Moreover, we also confirmed that the expression level of SDF-1 in the CAFs was negatively regulated by microRNA mir-1 through microRNA overexpression and quantitative PCR. Overall, our data provide one explanation for the effects of CAFs on lung cancer cells. Meanwhile, our results also suggest CAFs as a potential therapeutic target in tumor treatment.", "title": "mir-1-mediated paracrine effect of cancer-associated fibroblasts on lung cancer cell proliferation and chemoresistance." }, { "docid": "3559136", "text": "Tumor-associated macrophages (TAM) contribute to all aspects of tumor progression. Use of CSF1R inhibitors to target TAM is therapeutically appealing, but has had very limited anti-tumor effects. Here, we have identified the mechanism that limited the effect of CSF1R targeted therapy. We demonstrated that carcinoma-associated fibroblasts (CAF) are major sources of chemokines that recruit granulocytes to tumors. CSF1 produced by tumor cells caused HDAC2-mediated downregulation of granulocyte-specific chemokine expression in CAF, which limited migration of these cells to tumors. Treatment with CSF1R inhibitors disrupted this crosstalk and triggered a profound increase in granulocyte recruitment to tumors. Combining CSF1R inhibitor with a CXCR2 antagonist blocked granulocyte infiltration of tumors and showed strong anti-tumor effects.", "title": "Cancer-Associated Fibroblasts Neutralize the Anti-tumor Effect of CSF1 Receptor Blockade by Inducing PMN-MDSC Infiltration of Tumors." }, { "docid": "1727493", "text": "Advanced ovarian cancer usually spreads to the visceral adipose tissue of the omentum. However, the omental stromal cell-derived molecular determinants that modulate ovarian cancer growth have not been characterized. Here, using next-generation sequencing technology, we identify significantly higher levels of microRNA-21 (miR21) isomiRNAs in exosomes and tissue lysates isolated from cancer-associated adipocytes (CAAs) and fibroblasts (CAFs) than in those from ovarian cancer cells. Functional studies reveal that miR21 is transferred from CAAs or CAFs to the cancer cells, where it suppresses ovarian cancer apoptosis and confers chemoresistance by binding to its direct novel target, APAF1. These data suggest that the malignant phenotype of metastatic ovarian cancer cells can be altered by miR21 delivered by exosomes derived from neighbouring stromal cells in the omental tumour microenvironment, and that inhibiting the transfer of stromal-derived miR21 is an alternative modality in the treatment of metastatic and recurrent ovarian cancer.", "title": "Exosomal transfer of stroma-derived miR21 confers paclitaxel resistance in ovarian cancer cells through targeting APAF1" }, { "docid": "15832146", "text": "Fibroblasts often constitute the majority of the stromal cells within a breast carcinoma, yet the functional contributions of these cells to tumorigenesis are poorly understood. Using a coimplantation tumor xenograft model, we demonstrate that carcinoma-associated fibroblasts (CAFs) extracted from human breast carcinomas promote the growth of admixed breast carcinoma cells significantly more than do normal mammary fibroblasts derived from the same patients. The CAFs, which exhibit the traits of myofibroblasts, play a central role in promoting the growth of tumor cells through their ability to secrete stromal cell-derived factor 1 (SDF-1); CAFs promote angiogenesis by recruiting endothelial progenitor cells (EPCs) into carcinomas, an effect mediated in part by SDF-1. CAF-secreted SDF-1 also stimulates tumor growth directly, acting through the cognate receptor, CXCR4, which is expressed by carcinoma cells. Our findings indicate that fibroblasts within invasive breast carcinomas contribute to tumor promotion in large part through the secretion of SDF-1.", "title": "Stromal Fibroblasts Present in Invasive Human Breast Carcinomas Promote Tumor Growth and Angiogenesis through Elevated SDF-1/CXCL12 Secretion" }, { "docid": "3727986", "text": "Cancer-associated fibroblasts (CAFs) promote tumour invasion and metastasis. We show that CAFs exert a physical force on cancer cells that enables their collective invasion. Force transmission is mediated by a heterophilic adhesion involving N-cadherin at the CAF membrane and E-cadherin at the cancer cell membrane. This adhesion is mechanically active; when subjected to force it triggers β-catenin recruitment and adhesion reinforcement dependent on α-catenin/vinculin interaction. Impairment of E-cadherin/N-cadherin adhesion abrogates the ability of CAFs to guide collective cell migration and blocks cancer cell invasion. N-cadherin also mediates repolarization of the CAFs away from the cancer cells. In parallel, nectins and afadin are recruited to the cancer cell/CAF interface and CAF repolarization is afadin dependent. Heterotypic junctions between CAFs and cancer cells are observed in patient-derived material. Together, our findings show that a mechanically active heterophilic adhesion between CAFs and cancer cells enables cooperative tumour invasion.", "title": "A mechanically active heterotypic E-cadherin/N-cadherin adhesion enables fibroblasts to drive cancer cell invasion" }, { "docid": "27647593", "text": "Cancer cells do not exist as pure homogeneous populations in vivo. Instead they are embedded in \"cancer cell nests\" that are surrounded by stromal cells, especially cancer associated fibroblasts. Thus, it is not unreasonable to suspect that stromal fibroblasts could influence the metabolism of adjacent cancer cells, and visa versa. In accordance with this idea, we have recently proposed that the Warburg effect in cancer cells may be due to culturing cancer cells by themselves, out of their normal stromal context or tumor microenvironment. In fact, when cancer cells are co-cultured with fibroblasts, then cancer cells increase their mitochondrial mass, while fibroblasts lose their mitochondria. An in depth analysis of this phenomenon reveals that aggressive cancer cells are \"parasites\" that use oxidative stress as a \"weapon\" to extract nutrients from surrounding stromal cells. Oxidative stress in fibroblasts induces the autophagic destruction of mitochondria, by mitophagy. Then, stromal cells are forced to undergo aerobic glycolysis, and produce energy-rich nutrients (such as lactate and ketones) to \"feed\" cancer cells. This mechanism would allow cancer cells to seed anywhere, without blood vessels as a food source, as they could simply induce oxidative stress wherever they go, explaining how cancer cells survive during metastasis. We suggest that stromal catabolism, via autophagy and mitophagy, fuels the anabolic growth of tumor cells, promoting tumor progression and metastasis. We have previously termed this new paradigm \"The Autophagic Tumor Stroma Model of Cancer Metabolism\", or the \"Reverse Warburg Effect\". We also discuss how glutamine addiction (glutaminolysis) in cancer cells fits well with this new model, by promoting oxidative mitochondrial metabolism in aggressive cancer cells.", "title": "Stromal-epithelial metabolic coupling in cancer: integrating autophagy and metabolism in the tumor microenvironment." }, { "docid": "26735905", "text": "The tumor microenvironment plays a critical role in cancer progression, but the precise mechanisms by which stromal cells influence the epithelium are poorly understood. Here we show that p62 levels were reduced in the stroma of several tumors and that its loss in the tumor microenvironment or stromal fibroblasts resulted in increased tumorigenesis of epithelial prostate cancer cells. The mechanism involves the regulation of cellular redox through an mTORC1/c-Myc pathway of stromal glucose and amino acid metabolism, resulting in increased stromal IL-6 production, which is required for tumor promotion in the epithelial compartment. Thus, p62 is an anti-inflammatory tumor suppressor that acts through the modulation of metabolism in the tumor stroma.", "title": "Metabolic reprogramming of stromal fibroblasts through p62-mTORC1 signaling promotes inflammation and tumorigenesis." }, { "docid": "313403", "text": "The tumor microenvironment is composed of tumor cells, fibroblasts, endothelial cells and infiltrating immune cells, which may inhibit or promote tumor growth and progression. The objectives of this retrospective study were to characterize the density of tumor-associated macrophages (TAMs) in breast cancer, and to correlate the density of TAMs with clinicopathological parameters. Paraffin-embedded specimens and clinicopathological data, including up to 5 years follow-up information, were obtained from 172 breast cancer patients. Immunohistochemical staining for CD68 (marker for macrophages) was performed and evaluated in a blinded fashion. We found that TAMs were significantly frequent in high histopathological grade breast cancer patients. Breast cancer patients with a high density of TAMs had significantly lower rates of disease-free survival and 5-year overall survival than patients with low density of TAMs. Furthermore, high-infiltration of TAMs indicated worse survival rate for patients with node-negative breast cancer. In conclusion, the number of TAMs in the tumor stroma is an independent predictor of survival time for breast cancer patients. High-infiltration of TAMs is a significant unfavorable prognostic factor for patients with invasive breast cancer and, as such, is a potentially useful prognostic marker for breast cancer.", "title": "High-Infiltration of Tumor-Associated Macrophages Predicts Unfavorable Clinical Outcome for Node-Negative Breast Cancer" }, { "docid": "3376731", "text": "Various factors and cellular components in the tumor microenvironment are key drivers associated with drug resistance in many cancers. Here, we analyzed the factors and molecular mechanisms involved in chemoresistance in patients with esophageal squamous cell carcinoma (ESCC). We found that interleukin 6 (IL6) derived mainly from cancer-associated fibroblasts played the most important role in chemoresistance by upregulating C-X-C motif chemokine receptor 7 (CXCR7) expression through signal transducer and activator of transcription 3/nuclear factor-κB pathway. CXCR7 knockdown resulted in the inhibition of IL6-induced proliferation and chemoresistance. In addition, CXCR7 silencing significantly decreased gene expression associated with stemness, chemoresistance and epithelial–mesenchymal transition and suppressed the proliferation ability of ESCC cells in three-dimensional culture systems and angiogenesis assay. In clinical samples, ESCC patients with high expression of CXCR7 and IL6 presented a significantly worse overall survival and progression-free survival upon receiving cisplatin after operation. These results suggest that the IL6–CXCR7 axis may provide a promising target for the treatment of ESCC.", "title": "IL6 derived from cancer-associated fibroblasts promotes chemoresistance via CXCR7 in esophageal squamous cell carcinoma" }, { "docid": "22712546", "text": "Over the past years, plenty of evidence has emerged illustrating how metabolism supports many aspects of cellular function and how metabolic reprogramming can drive cell differentiation and fate. Here, we present a method to assess the metabolic configuration of single cells within their native tissue microenvironment via the visualization and quantification of multiple enzymatic activities measured at saturating substrate conditions combined with subsequent cell type identification. After careful validation of the approach and to demonstrate its potential, we assessed the intracellular metabolic configuration of different human immune cell populations in healthy and tumor colon tissue. Additionally, we analyzed the intercellular metabolic relationship between cancer cells and cancer-associated fibroblasts in a breast cancer tissue array. This study demonstrates that the determination of metabolic configurations in single cells could be a powerful complementary tool for every researcher interested to study metabolic networks in situ.", "title": "Exploring Metabolic Configurations of Single Cells within Complex Tissue Microenvironments." }, { "docid": "4429118", "text": "The mediators and cellular effectors of inflammation are important constituents of the local environment of tumours. In some types of cancer, inflammatory conditions are present before a malignant change occurs. Conversely, in other types of cancer, an oncogenic change induces an inflammatory microenvironment that promotes the development of tumours. Regardless of its origin, 'smouldering' inflammation in the tumour microenvironment has many tumour-promoting effects. It aids in the proliferation and survival of malignant cells, promotes angiogenesis and metastasis, subverts adaptive immune responses, and alters responses to hormones and chemotherapeutic agents. The molecular pathways of this cancer-related inflammation are now being unravelled, resulting in the identification of new target molecules that could lead to improved diagnosis and treatment.", "title": "Cancer-related inflammation" }, { "docid": "15727984", "text": "Non-small cell lung cancer (NSCLC) cells with somatic mutations in K-ras recruit to the tumor a variety of cell types (hereafter collectively termed \"stromal cells\") that can promote or inhibit tumorigenesis by mechanisms that have not been fully elucidated. Here, we postulated that stromal cells in the tumor microenvironment alter the tumor cell secretome, including those proteins required for tumor growth and dissemination, and we developed an in vitro model to test this hypothesis. Coculturing a murine K-ras mutant lung adenocarcinoma cell line (LKR-13) with a murine lung stromal cell (macrophage, endothelial cell, or fibroblast) enhanced stromal cell migration, induced endothelial tube formation, increased LKR-13 cell proliferation, and regulated the secretion of proteins involved in angiogenesis, inflammation, cell proliferation, and epithelial-to-mesenchymal transition. Among these proteins, CXCL1 has been reported to promote NSCLC development, whereas interleukin-18 (IL-18) has an undefined role. Genetic and pharmacologic strategies to inhibit CXCL1 and IL-18 revealed that stromal cell migration, LKR-13 cell proliferation, and LKR-13 cell tumorigenicity required one or both of these proteins. We conclude that stromal cells enhanced LKR-13 cell tumorigenicity partly through their effects on the secretome of LKR-13 cells. Strategies to inhibit tumor/stromal cell interactions may be useful as therapeutic approaches in NSCLC patients.", "title": "Identification of secreted proteins that mediate cell-cell interactions in an in vitro model of the lung cancer microenvironment." }, { "docid": "24349992", "text": "Loss of stromal fibroblast caveolin-1 (Cav-1) is a powerful single independent predictor of poor prognosis in human breast cancer patients, and is associated with early tumor recurrence, lymph node metastasis and tamoxifen-resistance. We developed a novel co-culture system to understand the mechanism(s) by which a loss of stromal fibroblast Cav-1 induces a \"lethal tumor micro-environment. \" Here, we propose a new paradigm to explain the powerful prognostic value of stromal Cav-1. In this model, cancer cells induce oxidative stress in cancer-associated fibroblasts, which then acts as a \"metabolic\" and \"mutagenic\" motor to drive tumor-stroma co-evolution, DNA damage and aneuploidy in cancer cells. More specifically, we show that an acute loss of Cav-1 expression leads to mitochondrial dysfunction, oxidative stress and aerobic glycolysis in cancer associated fibroblasts. Also, we propose that defective mitochondria are removed from cancer-associated fibroblasts by autophagy/mitophagy that is induced by oxidative stress. As a consequence, cancer associated fibroblasts provide nutrients (such as lactate) to stimulate mitochondrial biogenesis and oxidative metabolism in adjacent cancer cells (the \"Reverse Warburg Effect\"). We provide evidence that oxidative stress in cancer-associated fibroblasts is sufficient to induce genomic instability in adjacent cancer cells, via a bystander effect, potentially increasing their aggressive behavior. Finally, we directly demonstrate that nitric oxide (NO) over-production, secondary to Cav-1 loss, is the root cause for mitochondrial dysfunction in cancer associated fibroblasts. In support of this notion, treatment with anti-oxidants (such as N-acetyl-cysteine, metformin and quercetin) or NO inhibitors (L-NAME) was sufficient to reverse many of the cancer-associated fibroblast phenotypes that we describe. Thus, cancer cells use \"oxidative stress\" in adjacent fibroblasts (i) as an \"engine\" to fuel their own survival via the stromal production of nutrients and (ii) to drive their own mutagenic evolution towards a more aggressive phenotype, by promoting genomic instability. We also present evidence that the \"field effect\" in cancer biology could also be related to the stromal production of ROS and NO species. eNOS-expressing fibroblasts have the ability to downregulate Cav-1 and induce mitochondrial dysfunction in adjacent fibroblasts that do not express eNOS. As such, the effects of stromal oxidative stress can be laterally propagated, amplified and are effectively \"contagious\"--spread from cell-to-cell like a virus--creating an \"oncogenic/mutagenic\" field promoting widespread DNA damage.", "title": "Oxidative stress in cancer associated fibroblasts drives tumor-stroma co-evolution: A new paradigm for understanding tumor metabolism, the field effect and genomic instability in cancer cells." }, { "docid": "6807122", "text": "Activated fibroblasts are associated with many different tumors. Myofibroblasts, activated fibroblasts, and perivascular mesenchymal cells such as pericytes play a role in cancer progression. Many studies suggest that myofibroblasts facilitate tumor growth and cancer progression. The source for myofibroblasts and other activated fibroblasts within the tumors is still debated. Although de novo activation of quiescent fibroblasts into alpha-smooth muscle actin (alpha SMA)-positive myofibroblasts is one likely source, epithelial to mesenchymal transition and bone marrow recruitment are also evolving as possible mechanisms for the emergence of a heterogeneous population of carcinoma-associated fibroblasts. Here, we show that transforming growth factor-beta1 could induce proliferating endothelial cells to undergo a phenotypic conversion into fibroblast-like cells. Such endothelial to mesenchymal transition (EndMT) is associated with the emergence of mesenchymal marker fibroblast-specific protein-1 (FSP1) and down-regulation of CD31/PECAM. Additionally, we show EndMT in tumors using the B16F10 melanoma model and the Rip-Tag2 spontaneous pancreatic carcinoma model. Crossing Tie2-Cre mice with R26Rosa-lox-Stop-lox-LacZ mice allows for irreversible tagging of endothelial cells. We provide unequivocal evidence for EndMT at the invasive front of the tumors in these transgenic mice. Collectively, our results show that EndMT is a unique mechanism for the accumulation of carcinoma-associated fibroblasts and suggest that antiangiogenic treatment of tumors may have a direct effect in decreasing activated fibroblasts that likely facilitate cancer progression.", "title": "Discovery of endothelial to mesenchymal transition as a source for carcinoma-associated fibroblasts." }, { "docid": "13007205", "text": "Stromal fibroblasts can contribute to tumor invasion through the release of matrix metalloproteinases (MMPs). Population studies have suggested that single nucleotide polymorphisms (SNPs) in MMP genes influence levels of expression and may be associated with breast cancer risk and with disease progression. This study directly examined the impact of MMP SNP genotype on the ability of host fibroblasts to promote tumor cell invasion. Primary breast fibroblasts were isolated from patients with (n = 13) or without (n = 19) breast cancer, and their ability to promote breast cancer cell invasion was measured in in vitro invasion assays. Fibroblast invasion-promoting capacity (IPC) was analyzed in relation to donor type (tumor or non-tumor patient), MMP-1, MMP-3, and MMP-9 SNP genotype and MMP activity using independent samples t test and analysis of variance. All statistical tests were two-sided. Tumor-derived fibroblasts promoted higher levels of invasion than normal fibroblasts (p = 0.041). When IPC was related to genotype, higher levels of IPC were generated by tumor fibroblasts with the high-expressing MMP-3 5A/5A genotype compared with the 5A/6A and 6A/6A genotypes (p = 0.05 and 0.07, respectively), and this was associated with enhanced MMP-3 release. The functional importance of MMP-3 was demonstrated by enhanced invasion in the presence of recombinant MMP-3, whereas reduction occurred in the presence of a specific MMP-3 inhibitor. An inverse relationship was demonstrated between fibroblast IPC and the high-expressing MMP-1 genotype (p = 0.031), but no relationship was seen with MMP-9 SNP status. In contrast, normal fibroblasts showed no variation in IPC in relation to MMP genotype, with MMP-3 5A/5A fibroblasts exhibiting significantly lower levels of IPC than their tumor-derived counterparts (p = 0.04). This study has shown that tumor-derived fibroblasts exhibit higher levels of IPC than normal fibroblasts and that the MMP-3 5A/5A genotype contributes to this through enhanced MMP-3 release. Despite a high-expressing genotype, normal fibroblasts do not exhibit higher IPC or enhanced MMP release. This suggests that more complex changes occur in tumor-derived fibroblasts, enabling full expression of the MMP SNP genotype and these possibly are epigenetic in nature. The results do suggest that, in women with breast cancer, a high-expressing MMP-3 genotype may promote tumor progression more effectively.", "title": "Intrinsic genetic characteristics determine tumor-modifying capacity of fibroblasts: matrix metalloproteinase-3 5A/5A genotype enhances breast cancer cell invasion" } ]

[ { "docid": "6944800", "text": "Cancers develop in complex tissue environments, which they depend on for sustained growth, invasion and metastasis. Unlike tumor cells, stromal cell types within the tumor microenvironment (TME) are genetically stable and thus represent an attractive therapeutic target with reduced risk of resistance and tumor recurrence. However, specifically disrupting the pro-tumorigenic TME is a challenging undertaking, as the TME has diverse capacities to induce both beneficial and adverse consequences for tumorigenesis. Furthermore, many studies have shown that the microenvironment is capable of normalizing tumor cells, suggesting that re-education of stromal cells, rather than targeted ablation per se, may be an effective strategy for treating cancer. Here we discuss the paradoxical roles of the TME during specific stages of cancer progression and metastasis, as well as recent therapeutic attempts to re-educate stromal cells within the TME to have anti-tumorigenic effects.", "title": "Microenvironmental regulation of tumor progression and metastasis" } ]

[ { "docid": "3727986", "text": "Cancer-associated fibroblasts (CAFs) promote tumour invasion and metastasis. We show that CAFs exert a physical force on cancer cells that enables their collective invasion. Force transmission is mediated by a heterophilic adhesion involving N-cadherin at the CAF membrane and E-cadherin at the cancer cell membrane. This adhesion is mechanically active; when subjected to force it triggers β-catenin recruitment and adhesion reinforcement dependent on α-catenin/vinculin interaction. Impairment of E-cadherin/N-cadherin adhesion abrogates the ability of CAFs to guide collective cell migration and blocks cancer cell invasion. N-cadherin also mediates repolarization of the CAFs away from the cancer cells. In parallel, nectins and afadin are recruited to the cancer cell/CAF interface and CAF repolarization is afadin dependent. Heterotypic junctions between CAFs and cancer cells are observed in patient-derived material. Together, our findings show that a mechanically active heterophilic adhesion between CAFs and cancer cells enables cooperative tumour invasion.", "title": "A mechanically active heterotypic E-cadherin/N-cadherin adhesion enables fibroblasts to drive cancer cell invasion" }, { "docid": "32742683", "text": "Among cells present in the tumor microenvironment, activated fibroblasts termed cancer-associated fibroblasts (CAFs), play a critical role in the complex process of tumor-stroma interaction. CAFs, one of the prominent stromal cell populations in most types of human carcinomas, have been involved in tumor growth, angiogenesis, cancer stemness, extracellular matrix remodeling, tissue invasion, metastasis, and even chemoresistance. During the past decade, these activated tumor-associated fibroblasts have also been involved in the modulation of the anti-tumor immune response on various levels. In this review, we describe our current understanding of how CAFs accomplish this task as well as their potential therapeutic implications.", "title": "Alteration of the Antitumor Immune Response by Cancer-Associated Fibroblasts" }, { "docid": "8702697", "text": "AIMS Tumor microenvironment is a strong determinant for the acquisition of metastatic potential of cancer cells. We have recently demonstrated that cancer-associated fibroblasts (CAFs) elicit a redox-dependent epithelial-mesenchymal transition (EMT) in prostate cancer (PCa) cells, driven by cycloxygenase-2/hypoxia-inducible factor-1 (HIF-1)/nuclear factor-κB pathway and enhancing tumor aggressiveness. Here, we investigated the involvement of microRNAs (miRNAs) in tumor-stroma interplay to identify possible tools to counteract oxidative stress and metastasis dissemination. \n RESULTS We found that miR-205 is the most downmodulated miRNA in PCa cells upon CAF stimulation, due to direct transcriptional repression by HIF-1, a known redox-sensitive transcription factor. Rescue experiments demonstrated that ectopic miR-205 overexpression in PCa cells counteracts CAF-induced EMT, thus impairing enhancement of cell invasion, acquisition of stem cell traits, tumorigenicity, and metastatic dissemination. In addition, miR-205 blocks tumor-driven activation of surrounding fibroblasts by reducing pro-inflammatory cytokine secretion. INNOVATION Overall, such findings suggest miR-205 as a brake against PCa metastasis by blocking both the afferent and efferent arms of the circuit between tumor cells and associated fibroblasts, thus interrupting the pro-oxidant and pro-inflammatory circuitries engaged by reactive stroma. \n CONCLUSION The evidence that miR-205 replacement in PCa cells is able not only to prevent but also to revert the oxidative/pro-inflammatory axis leading to EMT induced by CAFs sets the rationale for developing miRNA-based approaches to prevent and treat metastatic disease.", "title": "miR-205 hinders the malignant interplay between prostate cancer cells and associated fibroblasts." }, { "docid": "952111", "text": "Cancer associated fibroblasts (CAFs) is one of the most crucial components of the tumor microenvironment which promotes the growth and invasion of cancer cells by various mechanisms. CAFs demonstrate a high degree of heterogeneity due to their various origins; however, many distinct morphological features and physiological functions of CAFs have been identified. It is becoming clear that the crosstalk between the cancer cells and the CAFs plays a key role in the progression of cancer, and understanding this mutual relationship would eventually enable us to treat cancer patients by targeting CAFs. In this review, we will discuss the latest findings on the role of CAFs in tumorigenesis and metastasis as well as potential therapeutic implication of CAFs.", "title": "Cancer associated fibroblasts (CAFs) in tumor microenvironment." }, { "docid": "9648896", "text": "Lung cancer is the leading cause of cancer-related mortality in humans worldwide. Moreover, the overall 5-year survival rate is only 15%. Pathologically almost 80% of all lung cancer cases are non-small cell lung cancer (NSCLC). Cancer-associated fibroblasts (CAFs) have been found to exist in a large number of NSCLCs. CAFs have been proven to promote tumor progression, metastasis and resistance to therapy through paracrine effects in most solid tumors. In the present study, firstly we isolated CAFs from patient tissues and demonstrated that they promoted cell proliferation and chemoresistance to cisplatin in the lung cancer cell lines A549 and 95D in a paracrine manner. Secondly, using ELISA and quantative PCR, we found that a higher amount of stromal cell-derived factor 1 (SDF-1) existed in the CAFs rather than that observed in the normal fibroblasts (NFs). Thirdly, we detected that SDF-1 facilitated lung cancer cell proliferation and drug resistance via the CXCR4-mediated signaling pathway which involved NF-κB and Bcl-xL. Moreover, we also confirmed that the expression level of SDF-1 in the CAFs was negatively regulated by microRNA mir-1 through microRNA overexpression and quantitative PCR. Overall, our data provide one explanation for the effects of CAFs on lung cancer cells. Meanwhile, our results also suggest CAFs as a potential therapeutic target in tumor treatment.", "title": "mir-1-mediated paracrine effect of cancer-associated fibroblasts on lung cancer cell proliferation and chemoresistance." }, { "docid": "35993767", "text": "Fibroblasts are rich in the surrounding microenvironment of hepatocellular carcinoma (HCC) because most HCCs occur in fibrotic or cirrhotic livers. However, the role of cancer-associated fibroblasts (CAFs) in HCC metastasis remains obscure. Here, we reported that CAFs promote the migration and invasion of HCC cells in vitro and facilitate the HCC metastasis to the bone, brain and lung in NOD/SCID mice. The RayBio human chemokine antibody array revealed that CAFs secret higher levels of CCL2, CCL5, CCL7 and CXCL16 than peri-tumor fibroblasts. CCL2 and CCL5 increase the migration but not the invasion of HCC cells, while CCL7 and CXCL16 promote both migration and invasion of HCC cells. Moreover, CCL2 and CCL5 stimulate the activation of the hedgehog (Hh) pathway, while CCL7 and CXCL16 enhance the activity of the transforming growth factor-β (TGF-β) pathway in HCC cells. The neutralizing antibodies of chemokines notably attenuate the effect of CAFs on HCC metastasis and compromised the activation of Hh and TGF-β pathways in HCC cells. In summary, CAF-secreted CCL2, CCL5, CCL7 and CXCL16 promote HCC metastasis through the coordinate activation of Hh and TGF-β pathways in HCC cells.", "title": "Cancer-associated fibroblasts promote hepatocellular carcinoma metastasis through chemokine-activated hedgehog and TGF-β pathways." }, { "docid": "10812605", "text": "Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.", "title": "Fibroblast heterogeneity in the cancer wound" }, { "docid": "1727493", "text": "Advanced ovarian cancer usually spreads to the visceral adipose tissue of the omentum. However, the omental stromal cell-derived molecular determinants that modulate ovarian cancer growth have not been characterized. Here, using next-generation sequencing technology, we identify significantly higher levels of microRNA-21 (miR21) isomiRNAs in exosomes and tissue lysates isolated from cancer-associated adipocytes (CAAs) and fibroblasts (CAFs) than in those from ovarian cancer cells. Functional studies reveal that miR21 is transferred from CAAs or CAFs to the cancer cells, where it suppresses ovarian cancer apoptosis and confers chemoresistance by binding to its direct novel target, APAF1. These data suggest that the malignant phenotype of metastatic ovarian cancer cells can be altered by miR21 delivered by exosomes derived from neighbouring stromal cells in the omental tumour microenvironment, and that inhibiting the transfer of stromal-derived miR21 is an alternative modality in the treatment of metastatic and recurrent ovarian cancer.", "title": "Exosomal transfer of stroma-derived miR21 confers paclitaxel resistance in ovarian cancer cells through targeting APAF1" }, { "docid": "3559136", "text": "Tumor-associated macrophages (TAM) contribute to all aspects of tumor progression. Use of CSF1R inhibitors to target TAM is therapeutically appealing, but has had very limited anti-tumor effects. Here, we have identified the mechanism that limited the effect of CSF1R targeted therapy. We demonstrated that carcinoma-associated fibroblasts (CAF) are major sources of chemokines that recruit granulocytes to tumors. CSF1 produced by tumor cells caused HDAC2-mediated downregulation of granulocyte-specific chemokine expression in CAF, which limited migration of these cells to tumors. Treatment with CSF1R inhibitors disrupted this crosstalk and triggered a profound increase in granulocyte recruitment to tumors. Combining CSF1R inhibitor with a CXCR2 antagonist blocked granulocyte infiltration of tumors and showed strong anti-tumor effects.", "title": "Cancer-Associated Fibroblasts Neutralize the Anti-tumor Effect of CSF1 Receptor Blockade by Inducing PMN-MDSC Infiltration of Tumors." }, { "docid": "15832146", "text": "Fibroblasts often constitute the majority of the stromal cells within a breast carcinoma, yet the functional contributions of these cells to tumorigenesis are poorly understood. Using a coimplantation tumor xenograft model, we demonstrate that carcinoma-associated fibroblasts (CAFs) extracted from human breast carcinomas promote the growth of admixed breast carcinoma cells significantly more than do normal mammary fibroblasts derived from the same patients. The CAFs, which exhibit the traits of myofibroblasts, play a central role in promoting the growth of tumor cells through their ability to secrete stromal cell-derived factor 1 (SDF-1); CAFs promote angiogenesis by recruiting endothelial progenitor cells (EPCs) into carcinomas, an effect mediated in part by SDF-1. CAF-secreted SDF-1 also stimulates tumor growth directly, acting through the cognate receptor, CXCR4, which is expressed by carcinoma cells. Our findings indicate that fibroblasts within invasive breast carcinomas contribute to tumor promotion in large part through the secretion of SDF-1.", "title": "Stromal Fibroblasts Present in Invasive Human Breast Carcinomas Promote Tumor Growth and Angiogenesis through Elevated SDF-1/CXCL12 Secretion" }, { "docid": "195680777", "text": "BACKGROUND Moderate differences in efficacy between adjuvant chemotherapy regimens for breast cancer are plausible, and could affect treatment choices. We sought any such differences. \n METHODS We undertook individual-patient-data meta-analyses of the randomised trials comparing: any taxane-plus-anthracycline-based regimen versus the same, or more, non-taxane chemotherapy (n=44,000); one anthracycline-based regimen versus another (n=7000) or versus cyclophosphamide, methotrexate, and fluorouracil (CMF; n=18,000); and polychemotherapy versus no chemotherapy (n=32,000). The scheduled dosages of these three drugs and of the anthracyclines doxorubicin (A) and epirubicin (E) were used to define standard CMF, standard 4AC, and CAF and CEF. Log-rank breast cancer mortality rate ratios (RRs) are reported. \n FINDINGS In trials adding four separate cycles of a taxane to a fixed anthracycline-based control regimen, extending treatment duration, breast cancer mortality was reduced (RR 0·86, SE 0·04, two-sided significance [2p]=0·0005). In trials with four such extra cycles of a taxane counterbalanced in controls by extra cycles of other cytotoxic drugs, roughly doubling non-taxane dosage, there was no significant difference (RR 0·94, SE 0·06, 2p=0·33). Trials with CMF-treated controls showed that standard 4AC and standard CMF were equivalent (RR 0·98, SE 0·05, 2p=0·67), but that anthracycline-based regimens with substantially higher cumulative dosage than standard 4AC (eg, CAF or CEF) were superior to standard CMF (RR 0·78, SE 0·06, 2p=0·0004). Trials versus no chemotherapy also suggested greater mortality reductions with CAF (RR 0·64, SE 0·09, 2p<0·0001) than with standard 4AC (RR 0·78, SE 0·09, 2p=0·01) or standard CMF (RR 0·76, SE 0·05, 2p<0·0001). In all meta-analyses involving taxane-based or anthracycline-based regimens, proportional risk reductions were little affected by age, nodal status, tumour diameter or differentiation (moderate or poor; few were well differentiated), oestrogen receptor status, or tamoxifen use. Hence, largely independently of age (up to at least 70 years) or the tumour characteristics currently available to us for the patients selected to be in these trials, some taxane-plus-anthracycline-based or higher-cumulative-dosage anthracycline-based regimens (not requiring stem cells) reduced breast cancer mortality by, on average, about one-third. 10-year overall mortality differences paralleled breast cancer mortality differences, despite taxane, anthracycline, and other toxicities. \n INTERPRETATION 10-year gains from a one-third breast cancer mortality reduction depend on absolute risks without chemotherapy (which, for oestrogen-receptor-positive disease, are the risks remaining with appropriate endocrine therapy). Low absolute risk implies low absolute benefit, but information was lacking about tumour gene expression markers or quantitative immunohistochemistry that might help to predict risk, chemosensitivity, or both. \n FUNDING Cancer Research UK; British Heart Foundation; UK Medical Research Council.", "title": "Comparisons between different polychemotherapy regimens for early breast cancer: meta-analyses of long-term outcome among 100,000 women in 123 randomised trials." }, { "docid": "11291348", "text": "The Maf oncoproteins are b-Zip transcription factors of the AP-1 superfamily. They are involved in developmental, metabolic, and tumorigenic processes. Maf proteins are overexpressed in about 50% of human multiple myelomas. Here, we show that Maf-transforming activity is controlled by GSK-3-dependent phosphorylation and that phosphorylation by GSK-3 can increase the oncogenic activity of a protein. Using microarray analysis, we identify a gene-expression subprogram regulated by GSK-3-mediated Maf phosphorylation involved in extracellular matrix remodeling and relevant to cancer progression. We also demonstrate that GSK-3 triggers MafA sequential phosphorylation on residues S61, T57, T53, and S49, inducing its ubiquitination and degradation. Paradoxically, this phosphorylation increases MafA-transcriptional activity through the recruitment of the coactivator P/CAF. We further demonstrate that P/CAF protects MafA from ubiquitination and degradation, suggesting that, upon the release of the coactivator complex, MafA becomes polyubiquitinated and degraded to allow the response to terminate.", "title": "GSK-3-mediated phosphorylation enhances Maf-transforming activity." }, { "docid": "12588500", "text": "Chromatin assembly factor 1 (CAF-1) and Rtt106 participate in the deposition of newly synthesized histones onto replicating DNA to form nucleosomes. This process is critical for the maintenance of genome stability and inheritance of functionally specialized chromatin structures in proliferating cells. However, the molecular functions of the acetylation of newly synthesized histones in this DNA replication-coupled nucleosome assembly pathway remain enigmatic. Here we show that histone H3 acetylated at lysine 56 (H3K56Ac) is incorporated onto replicating DNA and, by increasing the binding affinity of CAF-1 and Rtt106 for histone H3, H3K56Ac enhances the ability of these histone chaperones to assemble DNA into nucleosomes. Genetic analysis indicates that H3K56Ac acts in a nonredundant manner with the acetylation of the N-terminal residues of H3 and H4 in nucleosome assembly. These results reveal a mechanism by which H3K56Ac regulates replication-coupled nucleosome assembly mediated by CAF-1 and Rtt106.", "title": "Acetylation of Histone H3 Lysine 56 Regulates Replication-Coupled Nucleosome Assembly" }, { "docid": "6807122", "text": "Activated fibroblasts are associated with many different tumors. Myofibroblasts, activated fibroblasts, and perivascular mesenchymal cells such as pericytes play a role in cancer progression. Many studies suggest that myofibroblasts facilitate tumor growth and cancer progression. The source for myofibroblasts and other activated fibroblasts within the tumors is still debated. Although de novo activation of quiescent fibroblasts into alpha-smooth muscle actin (alpha SMA)-positive myofibroblasts is one likely source, epithelial to mesenchymal transition and bone marrow recruitment are also evolving as possible mechanisms for the emergence of a heterogeneous population of carcinoma-associated fibroblasts. Here, we show that transforming growth factor-beta1 could induce proliferating endothelial cells to undergo a phenotypic conversion into fibroblast-like cells. Such endothelial to mesenchymal transition (EndMT) is associated with the emergence of mesenchymal marker fibroblast-specific protein-1 (FSP1) and down-regulation of CD31/PECAM. Additionally, we show EndMT in tumors using the B16F10 melanoma model and the Rip-Tag2 spontaneous pancreatic carcinoma model. Crossing Tie2-Cre mice with R26Rosa-lox-Stop-lox-LacZ mice allows for irreversible tagging of endothelial cells. We provide unequivocal evidence for EndMT at the invasive front of the tumors in these transgenic mice. Collectively, our results show that EndMT is a unique mechanism for the accumulation of carcinoma-associated fibroblasts and suggest that antiangiogenic treatment of tumors may have a direct effect in decreasing activated fibroblasts that likely facilitate cancer progression.", "title": "Discovery of endothelial to mesenchymal transition as a source for carcinoma-associated fibroblasts." }, { "docid": "24349992", "text": "Loss of stromal fibroblast caveolin-1 (Cav-1) is a powerful single independent predictor of poor prognosis in human breast cancer patients, and is associated with early tumor recurrence, lymph node metastasis and tamoxifen-resistance. We developed a novel co-culture system to understand the mechanism(s) by which a loss of stromal fibroblast Cav-1 induces a \"lethal tumor micro-environment. \" Here, we propose a new paradigm to explain the powerful prognostic value of stromal Cav-1. In this model, cancer cells induce oxidative stress in cancer-associated fibroblasts, which then acts as a \"metabolic\" and \"mutagenic\" motor to drive tumor-stroma co-evolution, DNA damage and aneuploidy in cancer cells. More specifically, we show that an acute loss of Cav-1 expression leads to mitochondrial dysfunction, oxidative stress and aerobic glycolysis in cancer associated fibroblasts. Also, we propose that defective mitochondria are removed from cancer-associated fibroblasts by autophagy/mitophagy that is induced by oxidative stress. As a consequence, cancer associated fibroblasts provide nutrients (such as lactate) to stimulate mitochondrial biogenesis and oxidative metabolism in adjacent cancer cells (the \"Reverse Warburg Effect\"). We provide evidence that oxidative stress in cancer-associated fibroblasts is sufficient to induce genomic instability in adjacent cancer cells, via a bystander effect, potentially increasing their aggressive behavior. Finally, we directly demonstrate that nitric oxide (NO) over-production, secondary to Cav-1 loss, is the root cause for mitochondrial dysfunction in cancer associated fibroblasts. In support of this notion, treatment with anti-oxidants (such as N-acetyl-cysteine, metformin and quercetin) or NO inhibitors (L-NAME) was sufficient to reverse many of the cancer-associated fibroblast phenotypes that we describe. Thus, cancer cells use \"oxidative stress\" in adjacent fibroblasts (i) as an \"engine\" to fuel their own survival via the stromal production of nutrients and (ii) to drive their own mutagenic evolution towards a more aggressive phenotype, by promoting genomic instability. We also present evidence that the \"field effect\" in cancer biology could also be related to the stromal production of ROS and NO species. eNOS-expressing fibroblasts have the ability to downregulate Cav-1 and induce mitochondrial dysfunction in adjacent fibroblasts that do not express eNOS. As such, the effects of stromal oxidative stress can be laterally propagated, amplified and are effectively \"contagious\"--spread from cell-to-cell like a virus--creating an \"oncogenic/mutagenic\" field promoting widespread DNA damage.", "title": "Oxidative stress in cancer associated fibroblasts drives tumor-stroma co-evolution: A new paradigm for understanding tumor metabolism, the field effect and genomic instability in cancer cells." }, { "docid": "13007205", "text": "Stromal fibroblasts can contribute to tumor invasion through the release of matrix metalloproteinases (MMPs). Population studies have suggested that single nucleotide polymorphisms (SNPs) in MMP genes influence levels of expression and may be associated with breast cancer risk and with disease progression. This study directly examined the impact of MMP SNP genotype on the ability of host fibroblasts to promote tumor cell invasion. Primary breast fibroblasts were isolated from patients with (n = 13) or without (n = 19) breast cancer, and their ability to promote breast cancer cell invasion was measured in in vitro invasion assays. Fibroblast invasion-promoting capacity (IPC) was analyzed in relation to donor type (tumor or non-tumor patient), MMP-1, MMP-3, and MMP-9 SNP genotype and MMP activity using independent samples t test and analysis of variance. All statistical tests were two-sided. Tumor-derived fibroblasts promoted higher levels of invasion than normal fibroblasts (p = 0.041). When IPC was related to genotype, higher levels of IPC were generated by tumor fibroblasts with the high-expressing MMP-3 5A/5A genotype compared with the 5A/6A and 6A/6A genotypes (p = 0.05 and 0.07, respectively), and this was associated with enhanced MMP-3 release. The functional importance of MMP-3 was demonstrated by enhanced invasion in the presence of recombinant MMP-3, whereas reduction occurred in the presence of a specific MMP-3 inhibitor. An inverse relationship was demonstrated between fibroblast IPC and the high-expressing MMP-1 genotype (p = 0.031), but no relationship was seen with MMP-9 SNP status. In contrast, normal fibroblasts showed no variation in IPC in relation to MMP genotype, with MMP-3 5A/5A fibroblasts exhibiting significantly lower levels of IPC than their tumor-derived counterparts (p = 0.04). This study has shown that tumor-derived fibroblasts exhibit higher levels of IPC than normal fibroblasts and that the MMP-3 5A/5A genotype contributes to this through enhanced MMP-3 release. Despite a high-expressing genotype, normal fibroblasts do not exhibit higher IPC or enhanced MMP release. This suggests that more complex changes occur in tumor-derived fibroblasts, enabling full expression of the MMP SNP genotype and these possibly are epigenetic in nature. The results do suggest that, in women with breast cancer, a high-expressing MMP-3 genotype may promote tumor progression more effectively.", "title": "Intrinsic genetic characteristics determine tumor-modifying capacity of fibroblasts: matrix metalloproteinase-3 5A/5A genotype enhances breast cancer cell invasion" }, { "docid": "27647593", "text": "Cancer cells do not exist as pure homogeneous populations in vivo. Instead they are embedded in \"cancer cell nests\" that are surrounded by stromal cells, especially cancer associated fibroblasts. Thus, it is not unreasonable to suspect that stromal fibroblasts could influence the metabolism of adjacent cancer cells, and visa versa. In accordance with this idea, we have recently proposed that the Warburg effect in cancer cells may be due to culturing cancer cells by themselves, out of their normal stromal context or tumor microenvironment. In fact, when cancer cells are co-cultured with fibroblasts, then cancer cells increase their mitochondrial mass, while fibroblasts lose their mitochondria. An in depth analysis of this phenomenon reveals that aggressive cancer cells are \"parasites\" that use oxidative stress as a \"weapon\" to extract nutrients from surrounding stromal cells. Oxidative stress in fibroblasts induces the autophagic destruction of mitochondria, by mitophagy. Then, stromal cells are forced to undergo aerobic glycolysis, and produce energy-rich nutrients (such as lactate and ketones) to \"feed\" cancer cells. This mechanism would allow cancer cells to seed anywhere, without blood vessels as a food source, as they could simply induce oxidative stress wherever they go, explaining how cancer cells survive during metastasis. We suggest that stromal catabolism, via autophagy and mitophagy, fuels the anabolic growth of tumor cells, promoting tumor progression and metastasis. We have previously termed this new paradigm \"The Autophagic Tumor Stroma Model of Cancer Metabolism\", or the \"Reverse Warburg Effect\". We also discuss how glutamine addiction (glutaminolysis) in cancer cells fits well with this new model, by promoting oxidative mitochondrial metabolism in aggressive cancer cells.", "title": "Stromal-epithelial metabolic coupling in cancer: integrating autophagy and metabolism in the tumor microenvironment." }, { "docid": "15727984", "text": "Non-small cell lung cancer (NSCLC) cells with somatic mutations in K-ras recruit to the tumor a variety of cell types (hereafter collectively termed \"stromal cells\") that can promote or inhibit tumorigenesis by mechanisms that have not been fully elucidated. Here, we postulated that stromal cells in the tumor microenvironment alter the tumor cell secretome, including those proteins required for tumor growth and dissemination, and we developed an in vitro model to test this hypothesis. Coculturing a murine K-ras mutant lung adenocarcinoma cell line (LKR-13) with a murine lung stromal cell (macrophage, endothelial cell, or fibroblast) enhanced stromal cell migration, induced endothelial tube formation, increased LKR-13 cell proliferation, and regulated the secretion of proteins involved in angiogenesis, inflammation, cell proliferation, and epithelial-to-mesenchymal transition. Among these proteins, CXCL1 has been reported to promote NSCLC development, whereas interleukin-18 (IL-18) has an undefined role. Genetic and pharmacologic strategies to inhibit CXCL1 and IL-18 revealed that stromal cell migration, LKR-13 cell proliferation, and LKR-13 cell tumorigenicity required one or both of these proteins. We conclude that stromal cells enhanced LKR-13 cell tumorigenicity partly through their effects on the secretome of LKR-13 cells. Strategies to inhibit tumor/stromal cell interactions may be useful as therapeutic approaches in NSCLC patients.", "title": "Identification of secreted proteins that mediate cell-cell interactions in an in vitro model of the lung cancer microenvironment." }, { "docid": "22401720", "text": "Angiogenesis is a significant prognostic factor in breast cancer, but the factors that control angiogenesis in vivo are not well defined. Multiple angiogenic polypeptides are known, and we have determined the expression of seven of these in primary human breast cancers; the relationship of expression to estrogen receptor and vascular density was also examined. Vascular endothelial growth factor (VEGF) and its four isoforms (121, 165, 189, and 206 amino acids), transforming growth factor (TGF)-beta1, pleiotrophin, acidic and basic fibroblast growth factor (FGF), placental growth factor, and thymidine phosphorylase (platelet-derived endothelial cell growth factor) were quantitated by RNase protection analysis. beta-FGF was also measured by ELISA. The estrogen receptor (ER), epidermal growth factor receptor, and vascular density were analyzed in 64 primary breast cancers. All tumors expressed at least six different vascular growth factors. VEGF was most abundant, and the transcript for the 121-amino acid form predominated. Other angiogenic factors expressed at high levels were thymidine phosphorylase and TGF-beta1. Expression of most of the angiogenic factors did not correlate with that of ER or vascular density. However, thymidine phosphorylase did, with a correlation coefficient of 0.3 (P = 0.03). There were significant associations of pleiotrophin with acidic FGF expression (P = 0.001) and TGF-beta with platelet-derived endothelial cell growth factor expression (P = 0.001). Thus, angiogenesis may involve a coordinate regulation of some vascular growth factors. High VEGF expression correlated with poor prognosis in univariate analysis (P = 0.03), as did ER and epidermal growth factor receptor expression. Basic FGF was also assessed by ELISA and was more highly expressed in tumors than normal breast tissues (median, 346 microg/ml cytosol; range, 54-1323 versus median, 149; range, 32-509; P = 0.01). Implications for therapy are that broad spectrum agents that block features common to these factors may be useful (e.g., antagonism of heparin-binding activity agents), because so many angiogenic factors are expressed. Inhibiting endothelial migration or agents directly toxic to endothelium would be of value in a combined approach to therapy.", "title": "Expression of the angiogenic factors vascular endothelial cell growth factor, acidic and basic fibroblast growth factor, tumor growth factor beta-1, platelet-derived endothelial cell growth factor, placenta growth factor, and pleiotrophin in human primary breast cancer and its relation to angiogenes" }, { "docid": "25915873", "text": "PURPOSE Therapies to target prostate cancer bone metastases have only limited effects. New treatments are focused on the interaction between cancer cells, bone marrow cells and the bone matrix. Osteoclasts play an important role in the development of bone tumors caused by prostate cancer. Since Src kinase has been shown to be necessary for osteoclast function, we hypothesized that dasatinib, a Src family kinase inhibitor, would reduce osteoclast activity and prostate cancer (PC-3) cell-induced osteoclast formation. \n RESULTS Dasatinib inhibited RANKL-induced osteoclast differentiation of bone marrow-derived monocytes with an EC(50) of 7.5 nM. PC-3 cells, a human prostate cancer cell line, were able to differentiate RAW 264.7 cells, a murine monocytic cell line, into osteoclasts, and dasatinib inhibited this differentiation. In addition, conditioned medium from PC-3 cell cultures was able to differentiate RAW 264.7 cells into osteoclasts and this too, was inhibited by dasatinib. Even the lowest concentration of dasatinib, 1.25 nmol, inhibited osteoclast differentiation by 29%. Moreover, dasatinib inhibited osteoclast activity by 58% as measured by collagen 1 release. EXPERIMENTAL DESIGN We performed in vitro experiments utilizing the Src family kinase inhibitor dasatinib to target osteoclast activation as a means of inhibiting prostate cancer bone metastases. \n CONCLUSION Dasatinib inhibits osteoclast differentiation of mouse primary bone marrow-derived monocytes and PC-3 cell-induced osteoclast differentiation. Dasatinib also inhibits osteoclast degradation activity. Inhibiting osteoclast differentiation and activity may be an effective targeted therapy in patients with prostate cancer bone metastases.", "title": "Dasatinib inhibits both osteoclast activation and prostate cancer PC-3-cell-induced osteoclast formation." } ]

[ { "docid": "6944800", "text": "Cancers develop in complex tissue environments, which they depend on for sustained growth, invasion and metastasis. Unlike tumor cells, stromal cell types within the tumor microenvironment (TME) are genetically stable and thus represent an attractive therapeutic target with reduced risk of resistance and tumor recurrence. However, specifically disrupting the pro-tumorigenic TME is a challenging undertaking, as the TME has diverse capacities to induce both beneficial and adverse consequences for tumorigenesis. Furthermore, many studies have shown that the microenvironment is capable of normalizing tumor cells, suggesting that re-education of stromal cells, rather than targeted ablation per se, may be an effective strategy for treating cancer. Here we discuss the paradoxical roles of the TME during specific stages of cancer progression and metastasis, as well as recent therapeutic attempts to re-educate stromal cells within the TME to have anti-tumorigenic effects.", "title": "Microenvironmental regulation of tumor progression and metastasis" } ]

[ { "docid": "3727986", "text": "Cancer-associated fibroblasts (CAFs) promote tumour invasion and metastasis. We show that CAFs exert a physical force on cancer cells that enables their collective invasion. Force transmission is mediated by a heterophilic adhesion involving N-cadherin at the CAF membrane and E-cadherin at the cancer cell membrane. This adhesion is mechanically active; when subjected to force it triggers β-catenin recruitment and adhesion reinforcement dependent on α-catenin/vinculin interaction. Impairment of E-cadherin/N-cadherin adhesion abrogates the ability of CAFs to guide collective cell migration and blocks cancer cell invasion. N-cadherin also mediates repolarization of the CAFs away from the cancer cells. In parallel, nectins and afadin are recruited to the cancer cell/CAF interface and CAF repolarization is afadin dependent. Heterotypic junctions between CAFs and cancer cells are observed in patient-derived material. Together, our findings show that a mechanically active heterophilic adhesion between CAFs and cancer cells enables cooperative tumour invasion.", "title": "A mechanically active heterotypic E-cadherin/N-cadherin adhesion enables fibroblasts to drive cancer cell invasion" }, { "docid": "9648896", "text": "Lung cancer is the leading cause of cancer-related mortality in humans worldwide. Moreover, the overall 5-year survival rate is only 15%. Pathologically almost 80% of all lung cancer cases are non-small cell lung cancer (NSCLC). Cancer-associated fibroblasts (CAFs) have been found to exist in a large number of NSCLCs. CAFs have been proven to promote tumor progression, metastasis and resistance to therapy through paracrine effects in most solid tumors. In the present study, firstly we isolated CAFs from patient tissues and demonstrated that they promoted cell proliferation and chemoresistance to cisplatin in the lung cancer cell lines A549 and 95D in a paracrine manner. Secondly, using ELISA and quantative PCR, we found that a higher amount of stromal cell-derived factor 1 (SDF-1) existed in the CAFs rather than that observed in the normal fibroblasts (NFs). Thirdly, we detected that SDF-1 facilitated lung cancer cell proliferation and drug resistance via the CXCR4-mediated signaling pathway which involved NF-κB and Bcl-xL. Moreover, we also confirmed that the expression level of SDF-1 in the CAFs was negatively regulated by microRNA mir-1 through microRNA overexpression and quantitative PCR. Overall, our data provide one explanation for the effects of CAFs on lung cancer cells. Meanwhile, our results also suggest CAFs as a potential therapeutic target in tumor treatment.", "title": "mir-1-mediated paracrine effect of cancer-associated fibroblasts on lung cancer cell proliferation and chemoresistance." }, { "docid": "32742683", "text": "Among cells present in the tumor microenvironment, activated fibroblasts termed cancer-associated fibroblasts (CAFs), play a critical role in the complex process of tumor-stroma interaction. CAFs, one of the prominent stromal cell populations in most types of human carcinomas, have been involved in tumor growth, angiogenesis, cancer stemness, extracellular matrix remodeling, tissue invasion, metastasis, and even chemoresistance. During the past decade, these activated tumor-associated fibroblasts have also been involved in the modulation of the anti-tumor immune response on various levels. In this review, we describe our current understanding of how CAFs accomplish this task as well as their potential therapeutic implications.", "title": "Alteration of the Antitumor Immune Response by Cancer-Associated Fibroblasts" }, { "docid": "952111", "text": "Cancer associated fibroblasts (CAFs) is one of the most crucial components of the tumor microenvironment which promotes the growth and invasion of cancer cells by various mechanisms. CAFs demonstrate a high degree of heterogeneity due to their various origins; however, many distinct morphological features and physiological functions of CAFs have been identified. It is becoming clear that the crosstalk between the cancer cells and the CAFs plays a key role in the progression of cancer, and understanding this mutual relationship would eventually enable us to treat cancer patients by targeting CAFs. In this review, we will discuss the latest findings on the role of CAFs in tumorigenesis and metastasis as well as potential therapeutic implication of CAFs.", "title": "Cancer associated fibroblasts (CAFs) in tumor microenvironment." }, { "docid": "35993767", "text": "Fibroblasts are rich in the surrounding microenvironment of hepatocellular carcinoma (HCC) because most HCCs occur in fibrotic or cirrhotic livers. However, the role of cancer-associated fibroblasts (CAFs) in HCC metastasis remains obscure. Here, we reported that CAFs promote the migration and invasion of HCC cells in vitro and facilitate the HCC metastasis to the bone, brain and lung in NOD/SCID mice. The RayBio human chemokine antibody array revealed that CAFs secret higher levels of CCL2, CCL5, CCL7 and CXCL16 than peri-tumor fibroblasts. CCL2 and CCL5 increase the migration but not the invasion of HCC cells, while CCL7 and CXCL16 promote both migration and invasion of HCC cells. Moreover, CCL2 and CCL5 stimulate the activation of the hedgehog (Hh) pathway, while CCL7 and CXCL16 enhance the activity of the transforming growth factor-β (TGF-β) pathway in HCC cells. The neutralizing antibodies of chemokines notably attenuate the effect of CAFs on HCC metastasis and compromised the activation of Hh and TGF-β pathways in HCC cells. In summary, CAF-secreted CCL2, CCL5, CCL7 and CXCL16 promote HCC metastasis through the coordinate activation of Hh and TGF-β pathways in HCC cells.", "title": "Cancer-associated fibroblasts promote hepatocellular carcinoma metastasis through chemokine-activated hedgehog and TGF-β pathways." }, { "docid": "8702697", "text": "AIMS Tumor microenvironment is a strong determinant for the acquisition of metastatic potential of cancer cells. We have recently demonstrated that cancer-associated fibroblasts (CAFs) elicit a redox-dependent epithelial-mesenchymal transition (EMT) in prostate cancer (PCa) cells, driven by cycloxygenase-2/hypoxia-inducible factor-1 (HIF-1)/nuclear factor-κB pathway and enhancing tumor aggressiveness. Here, we investigated the involvement of microRNAs (miRNAs) in tumor-stroma interplay to identify possible tools to counteract oxidative stress and metastasis dissemination. \n RESULTS We found that miR-205 is the most downmodulated miRNA in PCa cells upon CAF stimulation, due to direct transcriptional repression by HIF-1, a known redox-sensitive transcription factor. Rescue experiments demonstrated that ectopic miR-205 overexpression in PCa cells counteracts CAF-induced EMT, thus impairing enhancement of cell invasion, acquisition of stem cell traits, tumorigenicity, and metastatic dissemination. In addition, miR-205 blocks tumor-driven activation of surrounding fibroblasts by reducing pro-inflammatory cytokine secretion. INNOVATION Overall, such findings suggest miR-205 as a brake against PCa metastasis by blocking both the afferent and efferent arms of the circuit between tumor cells and associated fibroblasts, thus interrupting the pro-oxidant and pro-inflammatory circuitries engaged by reactive stroma. \n CONCLUSION The evidence that miR-205 replacement in PCa cells is able not only to prevent but also to revert the oxidative/pro-inflammatory axis leading to EMT induced by CAFs sets the rationale for developing miRNA-based approaches to prevent and treat metastatic disease.", "title": "miR-205 hinders the malignant interplay between prostate cancer cells and associated fibroblasts." }, { "docid": "10812605", "text": "Fibroblasts regulate the structure and function of healthy tissues, participate transiently in tissue repair after acute inflammation, and assume an aberrant stimulatory role during chronic inflammatory states including cancer. Such cancer-associated fibroblasts (CAFs) modulate the tumor microenvironment and influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. These pleiotropic functions highlight the inherent plasticity of fibroblasts and may provide new avenues to understand and therapeutically intervene in malignancies. We discuss the emerging themes of CAF biology in the context of tumorigenesis and therapy.", "title": "Fibroblast heterogeneity in the cancer wound" }, { "docid": "3559136", "text": "Tumor-associated macrophages (TAM) contribute to all aspects of tumor progression. Use of CSF1R inhibitors to target TAM is therapeutically appealing, but has had very limited anti-tumor effects. Here, we have identified the mechanism that limited the effect of CSF1R targeted therapy. We demonstrated that carcinoma-associated fibroblasts (CAF) are major sources of chemokines that recruit granulocytes to tumors. CSF1 produced by tumor cells caused HDAC2-mediated downregulation of granulocyte-specific chemokine expression in CAF, which limited migration of these cells to tumors. Treatment with CSF1R inhibitors disrupted this crosstalk and triggered a profound increase in granulocyte recruitment to tumors. Combining CSF1R inhibitor with a CXCR2 antagonist blocked granulocyte infiltration of tumors and showed strong anti-tumor effects.", "title": "Cancer-Associated Fibroblasts Neutralize the Anti-tumor Effect of CSF1 Receptor Blockade by Inducing PMN-MDSC Infiltration of Tumors." }, { "docid": "1727493", "text": "Advanced ovarian cancer usually spreads to the visceral adipose tissue of the omentum. However, the omental stromal cell-derived molecular determinants that modulate ovarian cancer growth have not been characterized. Here, using next-generation sequencing technology, we identify significantly higher levels of microRNA-21 (miR21) isomiRNAs in exosomes and tissue lysates isolated from cancer-associated adipocytes (CAAs) and fibroblasts (CAFs) than in those from ovarian cancer cells. Functional studies reveal that miR21 is transferred from CAAs or CAFs to the cancer cells, where it suppresses ovarian cancer apoptosis and confers chemoresistance by binding to its direct novel target, APAF1. These data suggest that the malignant phenotype of metastatic ovarian cancer cells can be altered by miR21 delivered by exosomes derived from neighbouring stromal cells in the omental tumour microenvironment, and that inhibiting the transfer of stromal-derived miR21 is an alternative modality in the treatment of metastatic and recurrent ovarian cancer.", "title": "Exosomal transfer of stroma-derived miR21 confers paclitaxel resistance in ovarian cancer cells through targeting APAF1" }, { "docid": "15832146", "text": "Fibroblasts often constitute the majority of the stromal cells within a breast carcinoma, yet the functional contributions of these cells to tumorigenesis are poorly understood. Using a coimplantation tumor xenograft model, we demonstrate that carcinoma-associated fibroblasts (CAFs) extracted from human breast carcinomas promote the growth of admixed breast carcinoma cells significantly more than do normal mammary fibroblasts derived from the same patients. The CAFs, which exhibit the traits of myofibroblasts, play a central role in promoting the growth of tumor cells through their ability to secrete stromal cell-derived factor 1 (SDF-1); CAFs promote angiogenesis by recruiting endothelial progenitor cells (EPCs) into carcinomas, an effect mediated in part by SDF-1. CAF-secreted SDF-1 also stimulates tumor growth directly, acting through the cognate receptor, CXCR4, which is expressed by carcinoma cells. Our findings indicate that fibroblasts within invasive breast carcinomas contribute to tumor promotion in large part through the secretion of SDF-1.", "title": "Stromal Fibroblasts Present in Invasive Human Breast Carcinomas Promote Tumor Growth and Angiogenesis through Elevated SDF-1/CXCL12 Secretion" }, { "docid": "11291348", "text": "The Maf oncoproteins are b-Zip transcription factors of the AP-1 superfamily. They are involved in developmental, metabolic, and tumorigenic processes. Maf proteins are overexpressed in about 50% of human multiple myelomas. Here, we show that Maf-transforming activity is controlled by GSK-3-dependent phosphorylation and that phosphorylation by GSK-3 can increase the oncogenic activity of a protein. Using microarray analysis, we identify a gene-expression subprogram regulated by GSK-3-mediated Maf phosphorylation involved in extracellular matrix remodeling and relevant to cancer progression. We also demonstrate that GSK-3 triggers MafA sequential phosphorylation on residues S61, T57, T53, and S49, inducing its ubiquitination and degradation. Paradoxically, this phosphorylation increases MafA-transcriptional activity through the recruitment of the coactivator P/CAF. We further demonstrate that P/CAF protects MafA from ubiquitination and degradation, suggesting that, upon the release of the coactivator complex, MafA becomes polyubiquitinated and degraded to allow the response to terminate.", "title": "GSK-3-mediated phosphorylation enhances Maf-transforming activity." }, { "docid": "195680777", "text": "BACKGROUND Moderate differences in efficacy between adjuvant chemotherapy regimens for breast cancer are plausible, and could affect treatment choices. We sought any such differences. \n METHODS We undertook individual-patient-data meta-analyses of the randomised trials comparing: any taxane-plus-anthracycline-based regimen versus the same, or more, non-taxane chemotherapy (n=44,000); one anthracycline-based regimen versus another (n=7000) or versus cyclophosphamide, methotrexate, and fluorouracil (CMF; n=18,000); and polychemotherapy versus no chemotherapy (n=32,000). The scheduled dosages of these three drugs and of the anthracyclines doxorubicin (A) and epirubicin (E) were used to define standard CMF, standard 4AC, and CAF and CEF. Log-rank breast cancer mortality rate ratios (RRs) are reported. \n FINDINGS In trials adding four separate cycles of a taxane to a fixed anthracycline-based control regimen, extending treatment duration, breast cancer mortality was reduced (RR 0·86, SE 0·04, two-sided significance [2p]=0·0005). In trials with four such extra cycles of a taxane counterbalanced in controls by extra cycles of other cytotoxic drugs, roughly doubling non-taxane dosage, there was no significant difference (RR 0·94, SE 0·06, 2p=0·33). Trials with CMF-treated controls showed that standard 4AC and standard CMF were equivalent (RR 0·98, SE 0·05, 2p=0·67), but that anthracycline-based regimens with substantially higher cumulative dosage than standard 4AC (eg, CAF or CEF) were superior to standard CMF (RR 0·78, SE 0·06, 2p=0·0004). Trials versus no chemotherapy also suggested greater mortality reductions with CAF (RR 0·64, SE 0·09, 2p<0·0001) than with standard 4AC (RR 0·78, SE 0·09, 2p=0·01) or standard CMF (RR 0·76, SE 0·05, 2p<0·0001). In all meta-analyses involving taxane-based or anthracycline-based regimens, proportional risk reductions were little affected by age, nodal status, tumour diameter or differentiation (moderate or poor; few were well differentiated), oestrogen receptor status, or tamoxifen use. Hence, largely independently of age (up to at least 70 years) or the tumour characteristics currently available to us for the patients selected to be in these trials, some taxane-plus-anthracycline-based or higher-cumulative-dosage anthracycline-based regimens (not requiring stem cells) reduced breast cancer mortality by, on average, about one-third. 10-year overall mortality differences paralleled breast cancer mortality differences, despite taxane, anthracycline, and other toxicities. \n INTERPRETATION 10-year gains from a one-third breast cancer mortality reduction depend on absolute risks without chemotherapy (which, for oestrogen-receptor-positive disease, are the risks remaining with appropriate endocrine therapy). Low absolute risk implies low absolute benefit, but information was lacking about tumour gene expression markers or quantitative immunohistochemistry that might help to predict risk, chemosensitivity, or both. \n FUNDING Cancer Research UK; British Heart Foundation; UK Medical Research Council.", "title": "Comparisons between different polychemotherapy regimens for early breast cancer: meta-analyses of long-term outcome among 100,000 women in 123 randomised trials." }, { "docid": "12588500", "text": "Chromatin assembly factor 1 (CAF-1) and Rtt106 participate in the deposition of newly synthesized histones onto replicating DNA to form nucleosomes. This process is critical for the maintenance of genome stability and inheritance of functionally specialized chromatin structures in proliferating cells. However, the molecular functions of the acetylation of newly synthesized histones in this DNA replication-coupled nucleosome assembly pathway remain enigmatic. Here we show that histone H3 acetylated at lysine 56 (H3K56Ac) is incorporated onto replicating DNA and, by increasing the binding affinity of CAF-1 and Rtt106 for histone H3, H3K56Ac enhances the ability of these histone chaperones to assemble DNA into nucleosomes. Genetic analysis indicates that H3K56Ac acts in a nonredundant manner with the acetylation of the N-terminal residues of H3 and H4 in nucleosome assembly. These results reveal a mechanism by which H3K56Ac regulates replication-coupled nucleosome assembly mediated by CAF-1 and Rtt106.", "title": "Acetylation of Histone H3 Lysine 56 Regulates Replication-Coupled Nucleosome Assembly" }, { "docid": "15727984", "text": "Non-small cell lung cancer (NSCLC) cells with somatic mutations in K-ras recruit to the tumor a variety of cell types (hereafter collectively termed \"stromal cells\") that can promote or inhibit tumorigenesis by mechanisms that have not been fully elucidated. Here, we postulated that stromal cells in the tumor microenvironment alter the tumor cell secretome, including those proteins required for tumor growth and dissemination, and we developed an in vitro model to test this hypothesis. Coculturing a murine K-ras mutant lung adenocarcinoma cell line (LKR-13) with a murine lung stromal cell (macrophage, endothelial cell, or fibroblast) enhanced stromal cell migration, induced endothelial tube formation, increased LKR-13 cell proliferation, and regulated the secretion of proteins involved in angiogenesis, inflammation, cell proliferation, and epithelial-to-mesenchymal transition. Among these proteins, CXCL1 has been reported to promote NSCLC development, whereas interleukin-18 (IL-18) has an undefined role. Genetic and pharmacologic strategies to inhibit CXCL1 and IL-18 revealed that stromal cell migration, LKR-13 cell proliferation, and LKR-13 cell tumorigenicity required one or both of these proteins. We conclude that stromal cells enhanced LKR-13 cell tumorigenicity partly through their effects on the secretome of LKR-13 cells. Strategies to inhibit tumor/stromal cell interactions may be useful as therapeutic approaches in NSCLC patients.", "title": "Identification of secreted proteins that mediate cell-cell interactions in an in vitro model of the lung cancer microenvironment." }, { "docid": "2727303", "text": "Stromal-interaction molecule 1 (STIM1) is an endoplasmic reticulum Ca(2+) storage sensor that promotes cell growth, migration, and angiogenesis in breast and cervical cancers. Here, we report that the microtubule-associated histone deacetylase 6 (HDAC6) differentially regulates activation of STIM1-mediated store-operated Ca(2+) entry (SOCE) between cervical cancer cells and normal cervical epithelial cells. Confocal microscopy of living cells indicated that microtubule integrity was necessary for STIM1 trafficking to the plasma membrane and interaction with Orai1, an essential pore subunit of SOCE. Cancer cells overexpressed both STIM1 and Orai1 compared with normal cervical epithelial cells. HDAC6 upregulation in cancer cells was accompanied by hypoacetylated α-tubulin. Tubastatin-A, a specific HDAC6 inhibitor, inhibited STIM1 translocation to plasma membrane and blocked SOCE activation in cancer cells but not normal epithelial cells. Genetic or pharmacologic inhibition of HDAC6 blocked STIM1 membrane trafficking and downstream Ca(2+) influx, as evidenced by total internal reflection fluorescent images and intracellular Ca(2+) determination. In contrast, HDAC6 inhibition did not affect interactions between STIM1 and the microtubule plus end-binding protein EB1. Analysis of surgical specimens confirmed that most cervical cancer tissues overexpressed STIM1 and Orai1, accompanied by hypoacetylated α-tubulin. Together, our results identify HDAC6 as a candidate target to disrupt STIM1-mediated SOCE as a general strategy to block malignant cell behavior.", "title": "Microtubule-associated histone deacetylase 6 supports the calcium store sensor STIM1 in mediating malignant cell behaviors." }, { "docid": "6807122", "text": "Activated fibroblasts are associated with many different tumors. Myofibroblasts, activated fibroblasts, and perivascular mesenchymal cells such as pericytes play a role in cancer progression. Many studies suggest that myofibroblasts facilitate tumor growth and cancer progression. The source for myofibroblasts and other activated fibroblasts within the tumors is still debated. Although de novo activation of quiescent fibroblasts into alpha-smooth muscle actin (alpha SMA)-positive myofibroblasts is one likely source, epithelial to mesenchymal transition and bone marrow recruitment are also evolving as possible mechanisms for the emergence of a heterogeneous population of carcinoma-associated fibroblasts. Here, we show that transforming growth factor-beta1 could induce proliferating endothelial cells to undergo a phenotypic conversion into fibroblast-like cells. Such endothelial to mesenchymal transition (EndMT) is associated with the emergence of mesenchymal marker fibroblast-specific protein-1 (FSP1) and down-regulation of CD31/PECAM. Additionally, we show EndMT in tumors using the B16F10 melanoma model and the Rip-Tag2 spontaneous pancreatic carcinoma model. Crossing Tie2-Cre mice with R26Rosa-lox-Stop-lox-LacZ mice allows for irreversible tagging of endothelial cells. We provide unequivocal evidence for EndMT at the invasive front of the tumors in these transgenic mice. Collectively, our results show that EndMT is a unique mechanism for the accumulation of carcinoma-associated fibroblasts and suggest that antiangiogenic treatment of tumors may have a direct effect in decreasing activated fibroblasts that likely facilitate cancer progression.", "title": "Discovery of endothelial to mesenchymal transition as a source for carcinoma-associated fibroblasts." }, { "docid": "20183360", "text": "Transforming growth factor β (TGFβ) is a potent and context-dependent regulator of tumor progression. TGFβ promotes the lung metastasis of basal-like (but not the luminal-like) breast cancer. Here, we demonstrated that fascin, a pro-metastasis actin bundling protein, was a direct target of the canonical TGFβ-Smad4 signaling pathway in basal-like breast cancer cells. TGFβ and Smad4 induced fascin overexpression by directly binding to a Smad binding element on the fascin promoter. We identified GATA3, a transcription factor crucial for mammary gland morphogenesis and luminal differentiation, as a negative regulator of TGFβ- and Smad4-induced fascin overexpression. When ectopically expressed in basal-like breast cancer cells, GATA-3 abrogated TGFβ- and Smad4-mediated overexpression of fascin and other TGFβ response genes, invadopodium formation, cell migration, and invasion, suggesting suppression of the canonical TGFβ-Smad signaling axis. Mechanistically, GATA3 abrogated the canonical TGFβ-Smad signaling by abolishing interactions between Smad4 and its DNA binding elements, potentially through physical interactions between the N-terminal of GATA3 and Smad3/4 proteins. Our findings provide mechanistic insight into how TGFβ-mediated cell motility and invasiveness are differentially regulated in breast cancer.", "title": "GATA3 transcription factor abrogates Smad4 transcription factor-mediated fascin overexpression, invadopodium formation, and breast cancer cell invasion." }, { "docid": "24349992", "text": "Loss of stromal fibroblast caveolin-1 (Cav-1) is a powerful single independent predictor of poor prognosis in human breast cancer patients, and is associated with early tumor recurrence, lymph node metastasis and tamoxifen-resistance. We developed a novel co-culture system to understand the mechanism(s) by which a loss of stromal fibroblast Cav-1 induces a \"lethal tumor micro-environment. \" Here, we propose a new paradigm to explain the powerful prognostic value of stromal Cav-1. In this model, cancer cells induce oxidative stress in cancer-associated fibroblasts, which then acts as a \"metabolic\" and \"mutagenic\" motor to drive tumor-stroma co-evolution, DNA damage and aneuploidy in cancer cells. More specifically, we show that an acute loss of Cav-1 expression leads to mitochondrial dysfunction, oxidative stress and aerobic glycolysis in cancer associated fibroblasts. Also, we propose that defective mitochondria are removed from cancer-associated fibroblasts by autophagy/mitophagy that is induced by oxidative stress. As a consequence, cancer associated fibroblasts provide nutrients (such as lactate) to stimulate mitochondrial biogenesis and oxidative metabolism in adjacent cancer cells (the \"Reverse Warburg Effect\"). We provide evidence that oxidative stress in cancer-associated fibroblasts is sufficient to induce genomic instability in adjacent cancer cells, via a bystander effect, potentially increasing their aggressive behavior. Finally, we directly demonstrate that nitric oxide (NO) over-production, secondary to Cav-1 loss, is the root cause for mitochondrial dysfunction in cancer associated fibroblasts. In support of this notion, treatment with anti-oxidants (such as N-acetyl-cysteine, metformin and quercetin) or NO inhibitors (L-NAME) was sufficient to reverse many of the cancer-associated fibroblast phenotypes that we describe. Thus, cancer cells use \"oxidative stress\" in adjacent fibroblasts (i) as an \"engine\" to fuel their own survival via the stromal production of nutrients and (ii) to drive their own mutagenic evolution towards a more aggressive phenotype, by promoting genomic instability. We also present evidence that the \"field effect\" in cancer biology could also be related to the stromal production of ROS and NO species. eNOS-expressing fibroblasts have the ability to downregulate Cav-1 and induce mitochondrial dysfunction in adjacent fibroblasts that do not express eNOS. As such, the effects of stromal oxidative stress can be laterally propagated, amplified and are effectively \"contagious\"--spread from cell-to-cell like a virus--creating an \"oncogenic/mutagenic\" field promoting widespread DNA damage.", "title": "Oxidative stress in cancer associated fibroblasts drives tumor-stroma co-evolution: A new paradigm for understanding tumor metabolism, the field effect and genomic instability in cancer cells." }, { "docid": "52925737", "text": "BACKGROUND Exosomes are extracellular vesicles that mediate cellular communication in health and diseases. Neutrophils could be polarized to a pro-tumor phenotype by tumor. The function of tumor-derived exosomes in neutrophil regulation remains unclear. \n METHODS We investigated the effects of gastric cancer cell-derived exosomes (GC-Ex) on the pro-tumor activation of neutrophils and elucidated the underlying mechanisms. \n RESULTS GC-Ex prolonged neutrophil survival and induced expression of inflammatory factors in neutrophils. GC-Ex-activated neutrophils, in turn, promoted gastric cancer cell migration. GC-Ex transported high mobility group box-1 (HMGB1) that activated NF-κB pathway through interaction with TLR4, resulting in an increased autophagic response in neutrophils. Blocking HMGB1/TLR4 interaction, NF-κB pathway, and autophagy reversed GC-Ex-induced neutrophil activation. Silencing HMGB1 in gastric cancer cells confirmed HMGB1 as a key factor for GC-Ex-mediated neutrophil activation. Furthermore, HMGB1 expression was upregulated in gastric cancer tissues. Increased HMGB1 expression was associated with poor prognosis in patients with gastric cancer. Finally, gastric cancer tissue-derived exosomes acted similarly as exosomes derived from gastric cancer cell lines in neutrophil activation. \n CONCLUSION We demonstrate that gastric cancer cell-derived exosomes induce autophagy and pro-tumor activation of neutrophils via HMGB1/TLR4/NF-κB signaling, which provides new insights into mechanisms for neutrophil regulation in cancer and sheds lights on the multifaceted role of exosomes in reshaping tumor microenvironment.", "title": "Tumor-derived exosomes induce N2 polarization of neutrophils to promote gastric cancer cell migration" }, { "docid": "13889430", "text": "There is a growing interest in the cell-cell communication roles in cancer mediated by secreted vesicles termed exosomes. In this study, we examined whether exosomes produced by cancer cells could transmit information to normal stromal fibroblasts and trigger a cellular response. We found that some cancer-derived exosomes could trigger elevated α-smooth muscle actin expression and other changes consistent with the process of fibroblast differentiation into myofibroblasts. We show that TGF-β is expressed at the exosome surface in association with the transmembrane proteoglycan betaglycan. Although existing in a latent state, this complex was fully functional in eliciting SMAD-dependent signaling. Inhibiting either signaling or betaglycan expression attenuated differentiation. While the kinetics and overall magnitude of the response were similar to that achieved with soluble TGF-β, we identified important qualitative differences unique to the exosomal route of TGF-β delivery, as exemplified by a significant elevation in fibroblast FGF2 production. This hitherto unknown trigger for instigating cellular differentiation in a distinctive manner has major implications for mechanisms underlying cancer-recruited stroma, fibrotic diseases, and wound-healing responses.", "title": "Cancer exosomes trigger fibroblast to myofibroblast differentiation." } ]

[ { "docid": "26973393", "text": "All patients with metastatic lung, colorectal, pancreatic or head and neck cancers who initially benefit from epidermal growth factor receptor (EGFR)-targeted therapies eventually develop resistance. An increasing understanding of the number and complexity of resistance mechanisms highlights the Herculean challenge of killing tumors that are resistant to EGFR inhibitors. Our growing knowledge of resistance pathways provides an opportunity to develop new mechanism-based inhibitors and combination therapies to prevent or overcome therapeutic resistance in tumors. We present a comprehensive review of resistance pathways to EGFR-targeted therapies in lung, colorectal and head and neck cancers and discuss therapeutic strategies that are designed to circumvent resistance.", "title": "The quest to overcome resistance to EGFR-targeted therapies in cancer" } ]

[ { "docid": "22980205", "text": "PURPOSE OF REVIEW Greater understanding of the biology and genetics of urothelial carcinoma is helping to identify and define the role of molecules and pathways appropriate for novel-targeted therapies. Here, we review the targeted therapies that have been reported or are in ongoing urothelial carcinoma clinical trials, and highlight molecular targets characterized in preclinical and clinical studies. RECENT FINDINGS Trials in nonmuscle-invasive bladder cancer are evaluating the role of immunotherapy and agents targeting vascular endothelial growth factor (VEGF) or fibroblast growth factor receptor-3. In muscle-invasive bladder cancer, neoadjuvant studies have focused on combining VEGF agents with chemotherapy; adjuvant studies are testing vaccines and agents targeting the human epidermal growth factor receptor 2, p53, and Hsp27. In the first-line treatment of metastatic urothelial carcinoma, tubulin, cytotoxic T-lymphocyte antigen 4, Hsp27, and p53 are novel targets in clinical trials. The majority of targeted agents studied in urothelial carcinoma are in the second-line setting; new targets include CD105, polo-like kinase-1, phosphatidylinositide 3-kinases (PI3K), transforming growth factor β receptor/activin receptor-like kinase β, estrogen receptor, and the hepatocyte growth factor receptor (HGFR or MET). SUMMARY Development of targeted therapies for urothelial carcinoma is still in early stages, consequently there have been no major therapeutic advances to date. However, greater understanding of urothelial carcinoma and solid tumor biology has resulted in a proliferation of clinical trials that could lead to significant advances in treatment strategies.", "title": "Targeted therapies in urothelial carcinoma." }, { "docid": "6550579", "text": "Epidermal growth factor receptor (EGFR) and HER3 each form heterodimers with HER2 and have independently been implicated as key coreceptors that drive HER2-amplified breast cancer. Some studies suggest a dominant role for EGFR, a notion of renewed interest given the development of dual HER2/EGFR small-molecule inhibitors. Other studies point to HER3 as the primary coreceptor. To clarify the relative contributions of EGFR and HER3 to HER2 signaling, we studied receptor knockdown via small interfering RNA technology across a panel of six HER2-overexpressing cell lines. Interestingly, HER3 was as critical as HER2 for maintaining cell proliferation in most cell lines, whereas EGFR was dispensable. Induction of HER3 knockdown in the HER2-overexpressing BT474M1 cell line was found to inhibit growth in three-dimensional culture and induce rapid tumor regression of in vivo xenografts. Furthermore, preferential phosphorylation of HER3, but not EGFR, was observed in HER2-amplified breast cancer tissues. Given these data suggesting HER3 as an important therapeutic target, we examined the activity of pertuzumab, a HER2 antibody that inhibits HER3 signaling by blocking ligand-induced HER2/HER3 heterodimerization. Pertuzumab inhibited ligand-dependent morphogenesis in three-dimensional culture and induced tumor regression in the heregulin-dependent MDA-MB-175 xenograft model. Importantly, these activities of pertuzumab were distinct from those of trastuzumab, a monoclonal antibody currently used for treatment of HER2-amplified breast cancer patients. Our data suggest that inhibition of HER3 may be more clinically relevant than inhibition of EGFR in HER2-amplified breast cancer and also suggest that adding pertuzumab to trastuzumab may augment therapeutic benefit by blocking HER2/HER3 signaling.", "title": "A central role for HER3 in HER2-amplified breast cancer: implications for targeted therapy." }, { "docid": "38886345", "text": "BACKGROUND JX-594 is a targeted oncolytic poxvirus designed to selectively replicate in and destroy cancer cells with cell-cycle abnormalities and epidermal growth factor receptor (EGFR)-ras pathway activation. Direct oncolysis plus granulocyte-macrophage colony-stimulating factor (GM-CSF) expression also stimulates shutdown of tumour vasculature and antitumoral immunity. We aimed to assess intratumoral injection of JX-594 in patients with refractory primary or metastatic liver cancer. \n METHODS Between Jan 4, 2006, and July 4, 2007, 14 patients with histologically confirmed refractory primary or metastatic liver tumours (up to 10.9 cm total diameter) that were amenable to image-guided intratumoral injections were enrolled into this non-comparative, open-label, phase I dose-escalation trial (standard 3x3 design; two to six patients for each dose with 12-18 estimated total patients). Patients received one of four doses of intratumoral JX-594 (10(8) plaque-forming units [pfu], 3x10(8) pfu, 10(9) pfu, or 3x10(9) pfu) every 3 weeks at Dong-A University Hospital (Busan, South Korea). Patients were monitored after treatment for at least 48 h in hospital and for at least 4 weeks as out-patients. Adverse event-monitoring according to the National Cancer Institute Common Toxicity Criteria (version 3) and standard laboratory toxicity grading for haematology, liver and renal function, coagulation studies, serum chemistry, and urinalysis were done. The primary aims were to ascertain the maximum-tolerated dose (MTD) and safety of JX-594 treatment. Data were also collected on pharmacokinetics, pharmacodynamics, and efficacy. Analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00629759. \n FINDINGS Of 22 patients with liver tumours who were assessed for eligibility, eight patients did not meet inclusion criteria. Therefore, 14 patients, including those with hepatocellular, colorectal, melanoma, and lung cancer, were enrolled. Patients were heavily pretreated (5.6 previous treatments, SD 2.8, range 2.0-12.0) and had large tumours (7.0 cm diameter, SD 2.7, range 1.8-10.9). Patients received a mean of 3.4 (SD 2.2, range 1.0-8.0) cycles of JX-594. All patients were evaluable for toxicity. All patients experienced grade I-III flu-like symptoms, and four had transient grade I-III dose-related thrombocytopenia. Grade III hyperbilirubinaemia was dose-limiting in both patients at the highest dose; the MTD was therefore 1x10(9) pfu. JX-594 replication-dependent dissemination in blood was shown, with resultant infection of non-injected tumour sites. GM-CSF expression resulted in grade I-III increases in neutrophil counts in four of six patients at the MTD. Tumour responses were shown in injected and non-injected tumours. Ten patients were radiographically evaluable for objective responses; non-evaluable patients had contraindications to contrast medium (n=2) or no post-treatment scans (n=2). According to Response Evaluation Criteria in Solid Tumors (RECIST), three patients had partial response, six had stable disease, and one had progressive disease. \n INTERPRETATION Intratumoral injection of JX-594 into primary or metastatic liver tumours was generally well-tolerated. Direct hyperbilirubinaemia was the dose-limiting toxicity. Safety was acceptable in the context of JX-594 replication, GM-CSF expression, systemic dissemination, and JX-594 had anti-tumoral effects against several refractory carcinomas. Phase II trials are now underway.", "title": "Use of a targeted oncolytic poxvirus, JX-594, in patients with refractory primary or metastatic liver cancer: a phase I trial." }, { "docid": "5406411", "text": "Epidermal growth factor receptor (EGFR) is known to be critically involved in tissue development and homeostasis as well as in the pathogenesis of cancer. Here we showed that Foxp3(+) regulatory T (Treg) cells express EGFR under inflammatory conditions. Stimulation with the EGF-like growth factor Amphiregulin (AREG) markedly enhanced Treg cell function in vitro, and in a colitis and tumor vaccination model we showed that AREG was critical for efficient Treg cell function in vivo. In addition, mast cell-derived AREG fully restored optimal Treg cell function. These findings reveal EGFR as a component in the regulation of local immune responses and establish a link between mast cells and Treg cells. Targeting of this immune regulatory mechanism may contribute to the therapeutic successes of EGFR-targeting treatments in cancer patients.", "title": "Amphiregulin enhances regulatory T cell-suppressive function via the epidermal growth factor receptor." }, { "docid": "9486930", "text": "PURPOSE Glioblastomas are notorious for resistance to therapy, which has been attributed to DNA-repair proficiency, a multitude of deregulated molecular pathways, and, more recently, to the particular biologic behavior of tumor stem-like cells. Here, we aimed to identify molecular profiles specific for treatment resistance to the current standard of care of concomitant chemoradiotherapy with the alkylating agent temozolomide. \n PATIENTS AND METHODS Gene expression profiles of 80 glioblastomas were interrogated for associations with resistance to therapy. Patients were treated within clinical trials testing the addition of concomitant and adjuvant temozolomide to radiotherapy. \n RESULTS An expression signature dominated by HOX genes, which comprises Prominin-1 (CD133), emerged as a predictor for poor survival in patients treated with concomitant chemoradiotherapy (n = 42; hazard ratio = 2.69; 95% CI, 1.38 to 5.26; P = .004). This association could be validated in an independent data set. Provocatively, the HOX cluster was reminiscent of a \"self-renewal\" signature (P = .008; Gene Set Enrichment Analysis) recently characterized in a mouse leukemia model. The HOX signature and EGFR expression were independent prognostic factors in multivariate analysis, adjusted for the O-6-methylguanine-DNA methyltransferase (MGMT) methylation status, a known predictive factor for benefit from temozolomide, and age. Better outcome was associated with gene clusters characterizing features of tumor-host interaction including tumor vascularization and cell adhesion, and innate immune response. \n CONCLUSION This study provides first clinical evidence for the implication of a \"glioma stem cell\" or \"self-renewal\" phenotype in treatment resistance of glioblastoma. Biologic mechanisms identified here to be relevant for resistance will guide future targeted therapies and respective marker development for individualized treatment and patient selection.", "title": "Stem cell-related \"self-renewal\" signature and high epidermal growth factor receptor expression associated with resistance to concomitant chemoradiotherapy in glioblastoma." }, { "docid": "22401720", "text": "Angiogenesis is a significant prognostic factor in breast cancer, but the factors that control angiogenesis in vivo are not well defined. Multiple angiogenic polypeptides are known, and we have determined the expression of seven of these in primary human breast cancers; the relationship of expression to estrogen receptor and vascular density was also examined. Vascular endothelial growth factor (VEGF) and its four isoforms (121, 165, 189, and 206 amino acids), transforming growth factor (TGF)-beta1, pleiotrophin, acidic and basic fibroblast growth factor (FGF), placental growth factor, and thymidine phosphorylase (platelet-derived endothelial cell growth factor) were quantitated by RNase protection analysis. beta-FGF was also measured by ELISA. The estrogen receptor (ER), epidermal growth factor receptor, and vascular density were analyzed in 64 primary breast cancers. All tumors expressed at least six different vascular growth factors. VEGF was most abundant, and the transcript for the 121-amino acid form predominated. Other angiogenic factors expressed at high levels were thymidine phosphorylase and TGF-beta1. Expression of most of the angiogenic factors did not correlate with that of ER or vascular density. However, thymidine phosphorylase did, with a correlation coefficient of 0.3 (P = 0.03). There were significant associations of pleiotrophin with acidic FGF expression (P = 0.001) and TGF-beta with platelet-derived endothelial cell growth factor expression (P = 0.001). Thus, angiogenesis may involve a coordinate regulation of some vascular growth factors. High VEGF expression correlated with poor prognosis in univariate analysis (P = 0.03), as did ER and epidermal growth factor receptor expression. Basic FGF was also assessed by ELISA and was more highly expressed in tumors than normal breast tissues (median, 346 microg/ml cytosol; range, 54-1323 versus median, 149; range, 32-509; P = 0.01). Implications for therapy are that broad spectrum agents that block features common to these factors may be useful (e.g., antagonism of heparin-binding activity agents), because so many angiogenic factors are expressed. Inhibiting endothelial migration or agents directly toxic to endothelium would be of value in a combined approach to therapy.", "title": "Expression of the angiogenic factors vascular endothelial cell growth factor, acidic and basic fibroblast growth factor, tumor growth factor beta-1, platelet-derived endothelial cell growth factor, placenta growth factor, and pleiotrophin in human primary breast cancer and its relation to angiogenes" }, { "docid": "4820792", "text": "INTRODUCTION The overexpression of human epidermal growth factor receptor (HER)-2 in 20% of human breast cancers and its association with aggressive growth has led to widespread use of HER2-targeted therapies, such as trastuzumab (T) and lapatinib (L). Despite the success of these drugs, their efficacy is limited in patients whose tumors demonstrate de novo or acquired resistance to treatment. The β1 integrin resides on the membrane of the breast cancer cell, activating several elements of breast tumor progression including proliferation and survival. \n METHODS We developed a panel of HER2-overexpressing cell lines resistant to L, T, and the potent LT combination through long-term exposure and validated these models in 3D culture. Parental and L/T/LT-resistant cells were subject to HER2 and β1 integrin inhibitors in 3D and monitored for 12 days, followed by quantification of colony number. Parallel experiments were conducted where cells were either stained for Ki-67 and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) or harvested for protein and analyzed by immunoblot. Results were subjected to statistical testing using analysis of variance and linear contrasts, followed by adjustment with the Sidak method. \n RESULTS Using multiple cell lines including BT474 and HCC1954, we reveal that in L and LT resistance, where phosphorylation of EGFR/HER1, HER2, and HER3 are strongly inhibited, kinases downstream of β1 integrin--including focal adhesion kinase (FAK) and Src--are up-regulated. Blockade of β1 by the antibody AIIB2 abrogates this up-regulation and functionally achieves significant growth inhibition of L and LT resistant cells in 3D, without dramatically affecting the parental cells. SiRNA against β1 as well as pharmacologic inhibition of FAK achieve the same growth inhibitory effect. In contrast, trastuzumab-resistant cells, which retain high levels of phosphorylated EGFR/HER1, HER2, and HER3, are only modestly growth-inhibited by AIIB2. \n CONCLUSIONS Our data suggest that HER2 activity, which is suppressed in resistance involving L but not T alone, dictates whether β1 mediates an alternative pathway driving resistance. Our findings justify clinical studies investigating the inhibition of β1 or its downstream signaling moieties as strategies to overcome acquired L and LT resistance.", "title": "β1 integrin mediates an alternative survival pathway in breast cancer cells resistant to lapatinib" }, { "docid": "9929089", "text": "BACKGROUND Patients with advanced or metastatic non-small cell lung cancer (NSCLC) can develop acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib. Here, we report the successful treatment with alternating chemotherapy and TKIs of two cases of advanced NSCLC who developed resistance to TKI. CASE PRESENTATION Two patients with advanced or metastatic NSCLC were treated with palliative chemotherapy followed by erlotinib/gefitinib. When TKI therapy failed, two cycles of chemotherapy were provided, which were followed by re-challenge with erlotinib or gefitinib. \n CONCLUSION NSCLC patients with acquired TKI resistance should be managed aggressively whenever possible. Subsequent chemotherapy and target treatment is one of the reasonable choices for those with an initial dramatic clinical response with erlotinib/gefitinib treatment. Further studies are warranted to substantiate the association of erlotinib /gefitinib treatment with the efficacy of NSCLC patients with acquired TKI failure.", "title": "Subsequent chemotherapy reverses acquired tyrosine kinase inhibitor resistance and restores response to tyrosine kinase inhibitor in advanced non-small-cell lung cancer" }, { "docid": "9505402", "text": "Here we studied cell-free plasma DNA (cfDNA) collected from subjects with advanced lung cancer whose tumors had developed resistance to the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) AZD9291. We first performed next-generation sequencing of cfDNA from seven subjects and detected an acquired EGFR C797S mutation in one; expression of this mutant EGFR construct in a cell line rendered it resistant to AZD9291. We then performed droplet digital PCR on serial cfDNA specimens collected from 15 AZD9291-treated subjects. All were positive for the T790M mutation before treatment, but upon developing AZD9291 resistance three molecular subtypes emerged: six cases acquired the C797S mutation, five cases maintained the T790M mutation but did not acquire the C797S mutation and four cases lost the T790M mutation despite the presence of the underlying EGFR activating mutation. Our findings provide insight into the diversity of mechanisms through which tumors acquire resistance to AZD9291 and highlight the need for therapies that are able to overcome resistance mediated by the EGFR C797S mutation.", "title": "Acquired EGFR C797S mutation mediates resistance to AZD9291 in non–small cell lung cancer harboring EGFR T790M" }, { "docid": "86694016", "text": "Invadopodia are actin-rich membrane protrusions with a matrix degradation activity formed by invasive cancer cells. We have studied the molecular mechanisms of invadopodium formation in metastatic carcinoma cells. Epidermal growth factor (EGF) receptor kinase inhibitors blocked invadopodium formation in the presence of serum, and EGF stimulation of serum-starved cells induced invadopodium formation. RNA interference and dominant-negative mutant expression analyses revealed that neural WASP (N-WASP), Arp2/3 complex, and their upstream regulators, Nck1, Cdc42, and WIP, are necessary for invadopodium formation. Time-lapse analysis revealed that invadopodia are formed de novo at the cell periphery and their lifetime varies from minutes to several hours. Invadopodia with short lifetimes are motile, whereas long-lived invadopodia tend to be stationary. Interestingly, suppression of cofilin expression by RNA interference inhibited the formation of long-lived invadopodia, resulting in formation of only short-lived invadopodia with less matrix degradation activity. These results indicate that EGF receptor signaling regulates invadopodium formation through the N-WASP–Arp2/3 pathway and cofilin is necessary for the stabilization and maturation of invadopodia.", "title": "Molecular mechanisms of invadopodium formation: the role of the N-WASP–Arp2/3 complex pathway and cofilin" }, { "docid": "7028976", "text": "Epidermal growth factor receptor (EGFR) is a known diagnostic and, although controversial, prognostic marker of human glioblastoma multiforme (GBM). However, its functional role and biological significance in GBM remain elusive. Here, we show that multiple GBM cell subpopulations could be purified from the specimens of patients with GBM and from cancer stem cell (CSC) lines based on the expression of EGFR and of other putative CSC markers. All these subpopulations are molecularly and functionally distinct, are tumorigenic, and need to express EGFR to promote experimental tumorigenesis. Among them, EGFR-expressing tumor-initiating cells (TIC) display the most malignant functional and molecular phenotype. Accordingly, modulation of EGFR expression by gain-of-function and loss-of-function strategies in GBM CSC lines enhances and reduces their tumorigenic ability, respectively, suggesting that EGFR plays a fundamental role in gliomagenesis. These findings open up the possibility of new therapeutically relevant scenarios, as the presence of functionally heterogeneous EGFR(pos) and EGFR(neg) TIC subpopulations within the same tumor might affect clinical response to treatment.", "title": "Epidermal growth factor receptor expression identifies functionally and molecularly distinct tumor-initiating cells in human glioblastoma multiforme and is required for gliomagenesis." }, { "docid": "34066665", "text": "Breast cancer evolution and tumor progression are governed by the complex interactions between steroid receptor [estrogen receptor (ER) and progesterone receptor] and growth factor receptor signaling. In recent years, the field of cancer therapy has witnessed the emergence of multiple strategies targeting these specific cancer pathways and key molecules (ER and growth factor receptors) to arrest tumor growth and achieve tumor eradication; treatment success, however, has varied and both de novo (up front) and acquired resistance have proven a challenge. Recent studies of ER biology have revealed new insights into ER action in breast cancer and have highlighted the role of an intimate crosstalk between the ER and HER family signaling pathways as a fundamental contributor to the development of resistance to endocrine therapies against the ER pathway. The aim of this review article is to summarize the current knowledge on mechanisms of resistance of breast cancer cells to endocrine therapies due to the crosstalk between the ER and the HER growth factor receptor signaling pathways and to explore new available therapeutic strategies that could prolong duration of response and circumvent endocrine resistant tumor growth.", "title": "Crosstalk between the estrogen receptor and the HER tyrosine kinase receptor family: molecular mechanism and clinical implications for endocrine therapy resistance." }, { "docid": "32611468", "text": "Ghrelin, a 28 amino acid peptide hormone produced by the stomach, was the first orexigenic hormone to be discovered from the periphery. The octanoyl modification at Ser³, mediated by ghrelin O-acyltransferase (GOAT), is essential for ghrelin's biological activity. Ghrelin stimulates food intake through binding to its receptor (GRLN-R) on neurons in the arcuate nucleus of the hypothalamus. Ghrelin is widely expressed throughout the body; accordingly, it is implicated in several other physiological functions, which include growth hormone release, gastric emptying, and body weight regulation. Ghrelin and GRLN-R expression are also found in the pancreas, suggesting a local physiological role. Accordingly, several recent studies now point towards an important role for ghrelin and its receptor in the regulation of blood glucose homeostasis, which is the main focus of this review. Several mechanisms of this regulation by ghrelin have been proposed, and one possibility is through the regulation of insulin secretion. Despite some controversy, most studies suggest that ghrelin exerts an inhibitory effect on insulin secretion, resulting in increased circulating glucose levels. Ghrelin may thus be a diabetogenic factor. Obesity-related type 2 diabetes has become an increasingly important health problem, almost reaching epidemic proportions in the world; therefore, antagonists of the ghrelin-GOAT signaling pathway, which will tackle both energy- and glucose homeostasis, may be considered as promising new therapies for this disease.", "title": "Ghrelin's second life: from appetite stimulator to glucose regulator." }, { "docid": "41650417", "text": "PURPOSE To evaluate the effect of KRAS and epidermal growth factor receptor (EGFR) genotype on the response to erlotinib treatment in the BR.21, placebo-controlled trial. \n PATIENTS AND METHODS We analyzed 206 tumors for KRAS mutation, 204 tumors for EGFR mutation, and 159 tumors for EGFR gene copy by fluorescent in situ hybridization (FISH). We reanalyzed EGFR deletion/mutation using two highly sensitive techniques that detect abnormalities in samples with 5% to 10% tumor cellularity. KRAS mutation was analyzed by direct sequencing. \n RESULTS Thirty patients (15%) had KRAS mutations, 34 (17%) had EGFR exon 19 deletion or exon 21 L858R mutations, and 61 (38%) had high EGFR gene copy (FISH positive). Response rates were 10% for wild-type and 5% for mutant KRAS (P = .69), 7% for wild-type and 27% for mutant EGFR (P = .03), and 5% for EGFR FISH-negative and 21% for FISH-positive patients (P = .02). Significant survival benefit from erlotinib therapy was observed for patients with wild-type KRAS (hazard ratio [HR] = 0.69, P = .03) and EGFR FISH positivity (HR = 0.43, P = .004) but not for patients with mutant KRAS (HR = 1.67, P = .31), wild-type EGFR (HR = 0.74, P = .09), mutant EGFR (HR = 0.55, P = .12), and EGFR FISH negativity (HR = 0.80, P = .35). In multivariate analysis, only EGFR FISH-positive status was prognostic for poorer survival (P = .025) and predictive of differential survival benefit from erlotinib (P = .005). \n CONCLUSION EGFR mutations and high copy number are predictive of response to erlotinib. EGFR FISH is the strongest prognostic marker and a significant predictive marker of differential survival benefit from erlotinib.", "title": "Role of KRAS and EGFR as biomarkers of response to erlotinib in National Cancer Institute of Canada Clinical Trials Group Study BR.21." }, { "docid": "31616203", "text": "PURPOSE Brain metastases develop in one third of patients with advanced HER2+ breast cancer. Effective therapy for patients with central nervous system (CNS) progression after cranial radiation is extremely limited and represents a major clinical challenge. Lapatinib, an epidermal growth factor receptor/HER2 inhibitor, was associated with regressions of CNS lesions in a small phase 2 trial. The current study was done to further evaluate the CNS activity of lapatinib. The study was later amended to allow patients who progressed on lapatinib the option of receiving lapatinib plus capecitabine. EXPERIMENTAL DESIGN Eligible patients had HER2+ breast cancer, progressive brain metastases, prior trastuzumab, and cranial radiotherapy. The primary end point was CNS objective response, defined as >or=50% volumetric reduction of CNS lesion(s) in the absence of increasing steroid use, progressive neurologic signs and symptoms, or progressive extra-CNS disease. \n RESULTS Two-hundred and forty-two patients entered the study. CNS objective responses to lapatinib were observed in 6% of patients. In an exploratory analysis, 21% of patients experienced a >or=20% volumetric reduction in their CNS lesions. An association was observed between volumetric reduction and improvement in progression-free survival and neurologic signs and symptoms. Of the 50 evaluable patients who entered the lapatinib plus capecitabine extension, 20% experienced a CNS objective response and 40% experienced a >or=20% volumetric reduction in their CNS lesions. \n CONCLUSIONS This study confirms the modest CNS antitumor activity of lapatinib. Additional responses were observed with the combination of lapatinib and capecitabine. Further studies of lapatinib-based regimens for CNS metastases from HER2+ breast cancer are warranted.", "title": "Multicenter phase II study of lapatinib in patients with brain metastases from HER2-positive breast cancer." }, { "docid": "17648235", "text": "De-regulation of the wingless and integration site growth factor (WNT) signaling pathway via mutations in APC and Axin, proteins that target β-catenin for destruction, have been linked to various types of human cancer. These genetic alterations rarely, if ever, are observed in breast tumors. However, various lines of evidence suggest that WNT signaling may also be de-regulated in breast cancer. Most breast tumors show hypermethylation of the promoter region of secreted Frizzled-related protein 1 (sFRP1), a negative WNT pathway regulator, leading to downregulation of its expression. As a consequence, WNT signaling is enhanced and may contribute to proliferation of human breast tumor cells. We previously demonstrated that, in addition to the canonical WNT/β-catenin pathway, WNT signaling activates the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway in mouse mammary epithelial cells via epidermal growth factor receptor (EGFR) transactivation. Using the WNT modulator sFRP1 and short interfering RNA-mediated Dishevelled (DVL) knockdown, we interfered with autocrine WNT signaling at the ligand-receptor level. The impact on proliferation was measured by cell counting, YOPRO, and the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) assay; β-catenin, EGFR, ERK1/2 activation, and PARP (poly [ADP-ribose]polymerase) cleavages were assessed by Western blotting after treatment of human breast cancer cell lines with conditioned media, purified proteins, small-molecule inhibitors, or blocking antibodies. Phospho-DVL and stabilized β-catenin are present in many breast tumor cell lines, indicating autocrine WNT signaling activity. Interfering with this loop decreases active β-catenin levels, lowers ERK1/2 activity, blocks proliferation, and induces apoptosis in MDA-MB-231, BT474, SkBr3, JIMT-1, and MCF-7 cells. The effects of WNT signaling are mediated partly by EGFR transactivation in human breast cancer cells in a metalloprotease- and Src-dependent manner. Furthermore, Wnt1 rescues estrogen receptor-positive (ER+) breast cancer cells from the anti-proliferative effects of 4-hydroxytamoxifen (4-HT) and this activity can be blocked by an EGFR tyrosine kinase inhibitor. Our data show that interference with autocrine WNT signaling in human breast cancer reduces proliferation and survival of human breast cancer cells and rescues ER+ tumor cells from 4-HT by activation of the canonical WNT pathway and EGFR transactivation. These findings suggest that interference with WNT signaling at the ligand-receptor level in combination with other targeted therapies may improve the efficiency of breast cancer treatments.", "title": "Autocrine WNT signaling contributes to breast cancer cell proliferation via the canonical WNT pathway and EGFR transactivation" }, { "docid": "49432306", "text": "The introduction of immune-checkpoint blockade in the cancer therapy led to a paradigm change of the management of late stage cancers. There are already multiple FDA approved checkpoint inhibitors and many other agents are undergoing phase 2 and early phase 3 clinical trials. The therapeutic indication of immune checkpoint inhibitors expanded in the last years, but still remains unclear who can benefit. MicroRNAs are small RNAs with no coding potential. By complementary pairing to the 3' untranslated region of messenger RNA, microRNAs exert posttranscriptional control of protein expression. A network of microRNAs directly and indirectly controls the expression of checkpoint receptors and several microRNAs can target multiple checkpoint molecules, mimicking the therapeutic effect of a combined immune checkpoint blockade. In this review, we will describe the microRNAs that control the expression of immune checkpoints and we will present four specific issues of the immune checkpoint therapy in cancer: (1) imprecise therapeutic indication, (2) difficult response evaluation, (3) numerous immunologic adverse-events, and (4) the absence of response to immune therapy. Finally, we propose microRNAs as possible solutions for these pitfalls. We consider that in the near future microRNAs could become important therapeutic partners of the immune checkpoint therapy.", "title": "Key questions about the checkpoint blockade-are microRNAs an answer?" }, { "docid": "35443524", "text": "Cancer stem cells (CSCs) are a subpopulation of tumor cells that selectively possess tumor initiation and self-renewal capacity and the ability to give rise to bulk populations of nontumorigenic cancer cell progeny through differentiation. As we discuss here, they have been prospectively identified in several human malignancies, and their relative abundance in clinical cancer specimens has been correlated with malignant disease progression in human patients. Furthermore, recent findings suggest that clinical cancer progression driven by CSCs may contribute to the failure of existing therapies to consistently eradicate malignant tumors. Therefore, CSC-directed therapeutic approaches might represent translationally relevant strategies to improve clinical cancer therapy, in particular for those malignancies that are currently refractory to conventional anticancer agents directed predominantly at tumor bulk populations.", "title": "The therapeutic promise of the cancer stem cell concept." }, { "docid": "40710501", "text": "Because a subpopulation of cancer stem cells (tumor-initiating cells, TICs) is believed to be responsible for the development, progression, and recurrence of many tumors, we evaluated the in vitro sensitivity of human glioma TICs to epidermal growth factor receptor (EGFR) kinase inhibitors (erlotinib and gefitinib) and possible molecular determinants for their effects. Cells isolated from seven glioblastomas (GBM 1-7) and grown using neural stem cell permissive conditions were characterized for in vivo tumorigenicity, expression of tumor stem cell markers (CD133, nestin), and multilineage differentiation properties, confirming that these cultures are enriched in TICs. TIC cultures were challenged with increasing concentrations of erlotinib and gefitinib, and their survival was evaluated after 1-4 days. In most cases, a time- and concentration-dependent cell death was observed, although GBM 2 was completely insensitive to both drugs, and GBM 7 was responsive only to the highest concentrations tested. Using a radioligand binding assay, we show that all GBM TICs express EGFR. Erlotinib and gefitinib inhibited EGFR and ERK1/2 phosphorylation/activation in all GBMs, irrespective of the antiproliferative response observed. However, under basal conditions GBM 2 showed a high Akt phosphorylation that was completely insensitive to both drugs, whereas GBM 7 was completely insensitive to gefitinib, and Akt inactivation occurred only for the highest erlotinib concentration tested, showing a precise relationship with the antiproliferative effects of the drug. Interestingly, in GBM 2, phosphatase and tensin homolog expression was significantly down-regulated, possibly accounting for the insensitivity to the drugs. In conclusion, glioma TICs are responsive to anti-EGFR drugs, but phosphatase and tensin homolog expression and Akt inhibition seem to be necessary for such effect.", "title": "Different response of human glioma tumor-initiating cells to epidermal growth factor receptor kinase inhibitors." } ]

[ { "docid": "4928057", "text": "Organ-specific functions of tissue-resident macrophages in the steady-state heart are unknown. Here, we show that cardiac macrophages facilitate electrical conduction through the distal atrioventricular node, where conducting cells densely intersperse with elongated macrophages expressing connexin 43. When coupled to spontaneously beating cardiomyocytes via connexin-43-containing gap junctions, cardiac macrophages have a negative resting membrane potential and depolarize in synchrony with cardiomyocytes. Conversely, macrophages render the resting membrane potential of cardiomyocytes more positive and, according to computational modeling, accelerate their repolarization. Photostimulation of channelrhodopsin-2-expressing macrophages improves atrioventricular conduction, whereas conditional deletion of connexin 43 in macrophages and congenital lack of macrophages delay atrioventricular conduction. In the Cd11bDTR mouse, macrophage ablation induces progressive atrioventricular block. These observations implicate macrophages in normal and aberrant cardiac conduction.", "title": "Macrophages Facilitate Electrical Conduction in the Heart" } ]

[ { "docid": "12827098", "text": "Despite accumulating evidence suggesting local self-maintenance of tissue macrophages in the steady state, the dogma remains that tissue macrophages derive from monocytes. Using parabiosis and fate-mapping approaches, we confirmed that monocytes do not show significant contribution to tissue macrophages in the steady state. Similarly, we found that after depletion of lung macrophages, the majority of repopulation occurred by stochastic cellular proliferation in situ in a macrophage colony-stimulating factor (M-Csf)- and granulocyte macrophage (GM)-CSF-dependent manner but independently of interleukin-4. We also found that after bone marrow transplantation, host macrophages retained the capacity to expand when the development of donor macrophages was compromised. Expansion of host macrophages was functional and prevented the development of alveolar proteinosis in mice transplanted with GM-Csf-receptor-deficient progenitors. Collectively, these results indicate that tissue-resident macrophages and circulating monocytes should be classified as mononuclear phagocyte lineages that are independently maintained in the steady state.", "title": "Tissue-resident macrophages self-maintain locally throughout adult life with minimal contribution from circulating monocytes." }, { "docid": "43192375", "text": "Adipose tissue macrophages (ATMs) infiltrate adipose tissue during obesity and contribute to insulin resistance. We hypothesized that macrophages migrating to adipose tissue upon high-fat feeding may differ from those that reside there under normal diet conditions. To this end, we found a novel F4/80(+)CD11c(+) population of ATMs in adipose tissue of obese mice that was not seen in lean mice. ATMs from lean mice expressed many genes characteristic of M2 or \"alternatively activated\" macrophages, including Ym1, arginase 1, and Il10. Diet-induced obesity decreased expression of these genes in ATMs while increasing expression of genes such as those encoding TNF-alpha and iNOS that are characteristic of M1 or \"classically activated\" macrophages. Interestingly, ATMs from obese C-C motif chemokine receptor 2-KO (Ccr2-KO) mice express M2 markers at levels similar to those from lean mice. The antiinflammatory cytokine IL-10, which was overexpressed in ATMs from lean mice, protected adipocytes from TNF-alpha-induced insulin resistance. Thus, diet-induced obesity leads to a shift in the activation state of ATMs from an M2-polarized state in lean animals that may protect adipocytes from inflammation to an M1 proinflammatory state that contributes to insulin resistance.", "title": "Obesity induces a phenotypic switch in adipose tissue macrophage polarization." }, { "docid": "22406695", "text": "Macrophages are distributed in tissues throughout the body and contribute to both homeostasis and disease. Recently, it has become evident that most adult tissue macrophages originate during embryonic development and not from circulating monocytes. Each tissue has its own composition of embryonically derived and adult-derived macrophages, but it is unclear whether macrophages of distinct origins are functionally interchangeable or have unique roles at steady state. This new understanding also prompts reconsideration of the function of circulating monocytes. Classical Ly6c(hi) monocytes patrol the extravascular space in resting organs, and Ly6c(lo) nonclassical monocytes patrol the vasculature. Inflammation triggers monocytes to differentiate into macrophages, but whether resident and newly recruited macrophages possess similar functions during inflammation is unclear. Here, we define the tools used for identifying the complex origin of tissue macrophages and discuss the relative contributions of tissue niche versus ontological origin to the regulation of macrophage functions during steady state and inflammation.", "title": "Origin and functions of tissue macrophages." }, { "docid": "16863359", "text": "Inflammasomes are multiprotein complexes that link pathogen recognition and cellular stress to the processing of the proinflammatory cytokine interleukin-1β (IL-1β). Whereas inflammasome-mediated activation is heavily studied in hematopoietic macrophages and dendritic cells, much less is known about microglia, resident tissue macrophages of the brain that originate from a distinct progenitor. To directly compare inflammasome-mediated activation in different types of macrophages, we isolated primary microglia and hematopoietic macrophages from adult, healthy rhesus macaques. We analyzed the expression profile of NOD (nucleotide-binding oligomerization domain)-like receptors, adaptor proteins, and caspases and characterized inflammasome activation and regulation in detail. We here demonstrate that primary microglia can respond to the same innate stimuli as hematopoietic macrophages. However, microglial responses are more persistent due to lack of negative regulation on pro-IL-1β expression. In addition, we show that while caspase 1, 4, and 5 activation is pivotal for inflammasome-induced IL-1β secretion by hematopoietic macrophages, microglial secretion of IL-1β is only partially dependent on these inflammatory caspases. These results identify key cell type-specific differences that may aid the development of strategies to modulate innate immune responses in the brain.", "title": "Inflammasome-induced IL-1β secretion in microglia is characterized by delayed kinetics and is only partially dependent on inflammatory caspases." }, { "docid": "7521113", "text": "Mononuclear phagocytes, including monocytes, macrophages, and dendritic cells, contribute to tissue integrity as well as to innate and adaptive immune defense. Emerging evidence for labor division indicates that manipulation of these cells could bear therapeutic potential. However, specific ontogenies of individual populations and the overall functional organization of this cellular network are not well defined. Here we report a fate-mapping study of the murine monocyte and macrophage compartment taking advantage of constitutive and conditional CX(3)CR1 promoter-driven Cre recombinase expression. We have demonstrated that major tissue-resident macrophage populations, including liver Kupffer cells and lung alveolar, splenic, and peritoneal macrophages, are established prior to birth and maintain themselves subsequently during adulthood independent of replenishment by blood monocytes. Furthermore, we have established that short-lived Ly6C(+) monocytes constitute obligatory steady-state precursors of blood-resident Ly6C(-) cells and that the abundance of Ly6C(+) blood monocytes dynamically controls the circulation lifespan of their progeny.", "title": "Fate mapping reveals origins and dynamics of monocytes and tissue macrophages under homeostasis." }, { "docid": "8246090", "text": "Ion channels are classically understood to regulate the flux of ions across the plasma membrane in response to a variety of environmental and intracellular cues. Ion channels serve a number of functions in intracellular membranes as well. These channels may be temporarily localized to intracellular membranes as a function of their biosynthetic or secretory pathways, i.e., en route to their destination location. Intracellular membrane ion channels may also be located in the endocytic pathways, either being recycled back to the plasma membrane or targeted to the lysosome for degradation. Several channels do participate in intracellular signal transduction; the most well known example is the inositol 1,4,5-trisphosphate receptor (IP(3)R) in the endoplasmic reticulum. Some organellar intracellular membrane channels are required for the ionic homeostasis of their residing organelles. Several newly-discovered intracellular membrane Ca(2+) channels actually play active roles in membrane trafficking. Transient receptor potential (TRP) proteins are a superfamily (28 members in mammal) of Ca(2+)-permeable channels with diverse tissue distribution, subcellular localization, and physiological functions. Almost all mammalian TRP channels studied thus far, like their ancestor yeast TRP channel (TRPY1) that localizes to the vacuole compartment, are also (in addition to their plasma membrane localization) found to be localized to intracellular membranes. Accumulated evidence suggests that intracellularly-localized TRP channels actively participate in regulating membrane traffic, signal transduction, and vesicular ion homeostasis. This review aims to provide a summary of these recent works. The discussion will also be extended to the basic membrane and electrical properties of the TRP-residing compartments.", "title": "TRP channels of intracellular membranes." }, { "docid": "4460880", "text": "Endothelial cells contribute to a subset of cardiac fibroblasts by undergoing endothelial-to-mesenchymal transition, but whether cardiac fibroblasts can adopt an endothelial cell fate and directly contribute to neovascularization after cardiac injury is not known. Here, using genetic fate map techniques, we demonstrate that cardiac fibroblasts rapidly adopt an endothelial-cell-like phenotype after acute ischaemic cardiac injury. Fibroblast-derived endothelial cells exhibit anatomical and functional characteristics of native endothelial cells. We show that the transcription factor p53 regulates such a switch in cardiac fibroblast fate. Loss of p53 in cardiac fibroblasts severely decreases the formation of fibroblast-derived endothelial cells, reduces post-infarct vascular density and worsens cardiac function. Conversely, stimulation of the p53 pathway in cardiac fibroblasts augments mesenchymal-to-endothelial transition, enhances vascularity and improves cardiac function. These observations demonstrate that mesenchymal-to-endothelial transition contributes to neovascularization of the injured heart and represents a potential therapeutic target for enhancing cardiac repair.", "title": "Mesenchymal-endothelial-transition contributes to cardiac neovascularization" }, { "docid": "22281684", "text": "Wnt signaling has diverse actions in cardiovascular development and disease processes. Secreted frizzled-related protein 5 (Sfrp5) has been shown to function as an extracellular inhibitor of non-canonical Wnt signaling that is expressed at relatively high levels in white adipose tissue. The aim of this study was to investigate the role of Sfrp5 in the heart under ischemic stress. Sfrp5 KO and WT mice were subjected to ischemia/reperfusion (I/R). Although Sfrp5-KO mice exhibited no detectable phenotype when compared with WT control at baseline, they displayed larger infarct sizes, enhanced cardiac myocyte apoptosis, and diminished cardiac function following I/R. The ischemic lesions of Sfrp5-KO mice had greater infiltration of Wnt5a-positive macrophages and greater inflammatory cytokine and chemokine gene expression when compared with WT mice. In bone marrow-derived macrophages, Wnt5a promoted JNK activation and increased inflammatory gene expression, whereas treatment with Sfrp5 blocked these effects. These results indicate that Sfrp5 functions to antagonize inflammatory responses after I/R in the heart, possibly through a mechanism involving non-canonical Wnt5a/JNK signaling.", "title": "Secreted Frizzled-related Protein 5 Diminishes Cardiac Inflammation and Protects the Heart from Ischemia/Reperfusion Injury." }, { "docid": "3984231", "text": "Adverse remodeling following myocardial infarction (MI) leading to heart failure is driven by an imbalanced resolution of inflammation. The macrophage cell is an important control of post-MI inflammation, as macrophage subtypes secrete mediators to either promote inflammation and extend injury (M1 phenotype) or suppress inflammation and promote scar formation (M2 phenotype). We have previously shown that the absence of caveolin-1 (Cav1), a membrane scaffolding protein, is associated with adverse cardiac remodeling in mice, but the mechanisms responsible remain to be elucidated. We explore here the role of Cav1 in the activation of macrophages using wild type C57BL6/J (WT) and Cav1(tm1Mls/J) (Cav1(-/-)) mice. By echocardiography, cardiac function was comparable between WT and Cav1(-/-) mice at 3days post-MI. In the absence of Cav1, there were a surprisingly higher percentage of M2 macrophages (arginase-1 positive) detected in the infarcted zone. Conversely, restoring Cav1 function after MI in WT mice by adding back the Cav1 scaffolding domain reduced the M2 activation profile. Further, adoptive transfer of Cav1 null macrophages into WT mice on d3 post-MI exacerbated adverse cardiac remodeling at d14 post-MI. In vitro studies revealed that Cav1 null macrophages had a more pronounced M2 profile activation in response to IL-4 stimulation. In conclusion, Cav1 deletion promotes an array of maladaptive repair processes after MI, including increased TGF-β signaling, increased M2 macrophage infiltration and dysregulation of the M1/M2 balance. Our data also suggest that cardiac remodeling can be improved by therapeutic intervention regulating Cav1 function during the inflammatory response phase.", "title": "Caveolin-1 deletion exacerbates cardiac interstitial fibrosis by promoting M2 macrophage activation in mice after myocardial infarction." }, { "docid": "2832403", "text": "BACKGROUND Recent studies suggest that betaKlotho (KLB) and endocrine FGF19 and FGF21 redirect FGFR signaling to regulation of metabolic homeostasis and suppression of obesity and diabetes. However, the identity of the predominant metabolic tissue in which a major FGFR-KLB resides that critically mediates the differential actions and metabolism effects of FGF19 and FGF21 remain unclear. \n METHODOLOGY/PRINCIPAL FINDINGS We determined the receptor and tissue specificity of FGF21 in comparison to FGF19 by using direct, sensitive and quantitative binding kinetics, and downstream signal transduction and expression of early response gene upon administration of FGF19 and FGF21 in mice. We found that FGF21 binds FGFR1 with much higher affinity than FGFR4 in presence of KLB; while FGF19 binds both FGFR1 and FGFR4 in presence of KLB with comparable affinity. The interaction of FGF21 with FGFR4-KLB is very weak even at high concentration and could be negligible at physiological concentration. Both FGF19 and FGF21 but not FGF1 exhibit binding affinity to KLB. The binding of FGF1 is dependent on where FGFRs are present. Both FGF19 and FGF21 are unable to displace the FGF1 binding, and conversely FGF1 cannot displace FGF19 and FGF21 binding. These results indicate that KLB is an indispensable mediator for the binding of FGF19 and FGF21 to FGFRs that is not required for FGF1. Although FGF19 can predominantly activate the responses of the liver and to a less extent the adipose tissue, FGF21 can do so significantly only in the adipose tissue and adipocytes. Among several metabolic and endocrine tissues, the response of adipose tissue to FGF21 is predominant, and can be blunted by the ablation of KLB or FGFR1. \n CONCLUSIONS Our results indicate that unlike FGF19, FGF21 is unable to bind FGFR4-KLB complex with affinity comparable to FGFR1-KLB, and therefore, at physiological concentration less likely to directly and significantly target the liver where FGFR4-KLB predominantly resides. However, both FGF21 and FGF19 have the potential to activate responses of primarily the adipose tissue where FGFR1-KLB resides.", "title": "Differential Specificity of Endocrine FGF19 and FGF21 to FGFR1 and FGFR4 in Complex with KLB" }, { "docid": "12966719", "text": "CD8 tissue-resident memory T (TRM) cells provide efficient local control of viral infection, but the role of CD4 TRM is less clear. Here, by using parabiotic mice, we show that a preexisting pool of CD4 TRM cells in the genital mucosa was required for full protection from a lethal herpes simplex virus 2 (HSV-2) infection. Chemokines secreted by a local network of macrophages maintained vaginal CD4 TRM in memory lymphocyte clusters (MLCs), independently of circulating memory T cells. CD4 TRM cells within the MLCs were enriched in clones that expanded in response to HSV-2. Our results highlight the need for vaccine strategies that enable establishment of TRM cells for protection from a sexually transmitted virus and provide insights as to how such a pool might be established.", "title": "A local macrophage chemokine network sustains protective tissue-resident memory CD4 T cells" }, { "docid": "8477699", "text": "Studying the metabolism of immune cells in recent years has emphasized the tight link existing between the metabolic state and the phenotype of these cells. Macrophages in particular are a good example of this phenomenon. Whether the macrophage obtains its energy through glycolysis or through oxidative metabolism can give rise to different phenotypes. Classically activated or M1 macrophages are key players of the first line of defense against bacterial infections and are known to obtain energy through glycolysis. Alternatively activated or M2 macrophages on the other hand are involved in tissue repair and wound healing and use oxidative metabolism to fuel their longer-term functions. Metabolic intermediates, however, are not just a source of energy but can be directly implicated in a particular macrophage phenotype. In M1 macrophages, the Krebs cycle intermediate succinate regulates HIF1α, which is responsible for driving the sustained production of the pro-inflammatory cytokine IL1β. In M2 macrophages, the sedoheptulose kinase carbohydrate kinase-like protein is critical for regulating the pentose phosphate pathway. The potential to target these events and impact on disease is an exciting prospect.", "title": "Metabolic Reprograming in Macrophage Polarization" }, { "docid": "21868715", "text": "Molecular mechanisms leading to myocardial injury during warm or cold ischemia are insufficiently understood. Although proteasomes are thought to contribute to myocardial ischemia-reperfusion injury, their roles during the ischemic period remain elusive. Because donor hearts are commonly exposed to prolonged global cold ischemia prior to cardiac transplantation, we evaluated the role and regulation of the proteasome during cold ischemic storage of rat hearts in context of the myocardial ATP content. When measured at the actual tissue ATP concentration, cardiac proteasome peptidase activity increased by 225% as ATP declined during cold ischemic storage of hearts in University of Wisconsin (UW) solution for up to 48h. Addition of the specific proteasome inhibitor epoxomicin to the UW solution inhibited proteasome activity in the cardiac extracts, significantly reduced edema formation and preserved the ultrastructural integrity of the cardiomyocyte. Utilizing purified 20S/26S proteasome enzyme preparations, we demonstrate that this activation can be attributed to a subset of 26S proteasomes which are stable at ATP concentrations far below physiological levels, that ATP negatively regulates its activity and that maximal activation occurs at ATP concentrations in the low mumol/L range. These data suggest that proteasome activation is a pathophysiologically relevant mechanism of cold ischemic myocardial injury. A subset of 26S proteasomes appears to be a cell-destructive protease that is activated as ATP levels decline. Proteasome inhibition during cold ischemia preserves the ultrastructural integrity of the cardiomyocyte.", "title": "A subset of 26S proteasomes is activated at critically low ATP concentrations and contributes to myocardial injury during cold ischemia." }, { "docid": "27567994", "text": "The generation of tumor-directed cytotoxic T lymphocytes is considered crucial for the induction of antitumor immunity. To activate these CD8(+) T cells, antigen-presenting cells (APCs) must initially acquire tumor cell-associated antigens. The major source of tumor antigens is dead tumor cells, but little is known about how APCs in draining lymph nodes acquire and crosspresent these antigens. Here we show that CD169(+) macrophages phagocytose dead tumor cells transported via lymphatic flow and subsequently crosspresent tumor antigens to CD8(+) T cells. Subcutaneous immunization with irradiated tumor cells protects mice from syngenic tumor. However, tumor antigen-specific CD8(+) T cell activation and subsequent antitumor immunity are severely impaired in mice depleted with CD169(+) macrophages. Neither migratory dendritic cells (DCs) nor lymph node-resident conventional DCs are essential for the crosspresentation of tumor antigens. Thus, we have identified CD169(+) macrophages as lymph node-resident APCs dominating early activation of tumor antigen-specific CD8(+) T cells.", "title": "CD169-positive macrophages dominate antitumor immunity by crosspresenting dead cell-associated antigens." }, { "docid": "9122283", "text": "RATIONALE Multiple biological mechanisms contribute to the efficacy of cardiac cell therapy. Most prominent among these are direct heart muscle and blood vessel regeneration from transplanted cells, as opposed to paracrine enhancement of tissue preservation and/or recruitment of endogenous repair. \n OBJECTIVE Human cardiac progenitor cells, cultured as cardiospheres (CSps) or as CSp-derived cells (CDCs), have been shown to be capable of direct cardiac regeneration in vivo. Here we characterized paracrine effects in CDC transplantation and investigated their relative importance versus direct differentiation of surviving transplanted cells. \n METHODS AND RESULTS In vitro, many growth factors were found in media conditioned by human adult CSps and CDCs; CDC-conditioned media exerted antiapoptotic effects on neonatal rat ventricular myocytes, and proangiogenic effects on human umbilical vein endothelial cells. In vivo, human CDCs secreted vascular endothelial growth factor, hepatocyte growth factor, and insulin-like growth factor 1 when transplanted into the same SCID mouse model of acute myocardial infarction where they were previously shown to improve function and to produce tissue regeneration. Injection of CDCs in the peri-infarct zone increased the expression of Akt, decreased apoptotic rate and caspase 3 level, and increased capillary density, indicating overall higher tissue resilience. Based on the number of human-specific cells relative to overall increases in capillary density and myocardial viability, direct differentiation quantitatively accounted for 20% to 50% of the observed effects. \n CONCLUSIONS Together with their spontaneous commitment to cardiac and angiogenic differentiation, transplanted CDCs serve as \"role models,\" recruiting endogenous regeneration and improving tissue resistance to ischemic stress. The contribution of the role model effect rivals or exceeds that of direct regeneration.", "title": "Relative roles of direct regeneration versus paracrine effects of human cardiosphere-derived cells transplanted into infarcted mice." }, { "docid": "20460020", "text": "Efficient local monocyte/macrophage recruitment is critical for tissue repair. Recruited macrophages are polarized toward classical (proinflammatory) or alternative (prohealing) activation in response to cytokines, with tight temporal regulation crucial for efficient wound repair. Estrogen acts as a potent anti-inflammatory regulator of cutaneous healing. However, an understanding of estrogen/estrogen receptor (ER) contribution to macrophage polarization and subsequent local effects on wound healing is lacking. Here we identify, to our knowledge previously unreported, a role whereby estrogen receptor α (ERα) signaling preferentially polarizes macrophages from a range of sources to an alternative phenotype. Cell-specific ER ablation studies confirm an in vivo role for inflammatory cell ERα, but not ERβ, in poor healing associated with an altered cytokine profile and fewer alternatively activated macrophages. Furthermore, we reveal intrinsic changes in ERα-deficient macrophages, which are unable to respond to alternative activation signals in vitro. Collectively, our data reveal that inflammatory cell-expressed ERα promotes alternative macrophage polarization, which is beneficial for timely healing. Given the diverse physiological roles of ERs, these findings will likely be of relevance to many pathologies involving excessive inflammation.", "title": "Estrogen receptor-alpha promotes alternative macrophage activation during cutaneous repair." }, { "docid": "7489663", "text": "A current paradigm states that monocytes circulate freely and patrol blood vessels but differentiate irreversibly into dendritic cells (DCs) or macrophages upon tissue entry. Here we show that bona fide undifferentiated monocytes reside in the spleen and outnumber their equivalents in circulation. The reservoir monocytes assemble in clusters in the cords of the subcapsular red pulp and are distinct from macrophages and DCs. In response to ischemic myocardial injury, splenic monocytes increase their motility, exit the spleen en masse, accumulate in injured tissue, and participate in wound healing. These observations uncover a role for the spleen as a site for storage and rapid deployment of monocytes and identify splenic monocytes as a resource that the body exploits to regulate inflammation.", "title": "Identification of splenic reservoir monocytes and their deployment to inflammatory sites." }, { "docid": "5511240", "text": "Kupffer cells, the phagocytes of fetal origin that line the liver sinusoids, are key contributors of host defense against enteroinvasive bacteria. Here, we found that infection by Listeria monocytogenes induced the early necroptotic death of Kupffer cells, which was followed by monocyte recruitment and an anti-bacterial type 1 inflammatory response. Kupffer cell death also triggered a type 2 response that involved the hepatocyte-derived alarmin interleukin-33 (IL-33) and basophil-derived interleukin-4 (IL-4). This led to the alternative activation of the monocyte-derived macrophages recruited to the liver, which thereby replaced ablated Kupffer cells and restored liver homeostasis. Kupffer cell death is therefore a key signal orchestrating type 1 microbicidal inflammation and type-2-mediated liver repair upon infection. This indicates that beyond the classical dichotomy of type 1 and type 2 responses, these responses can develop sequentially in the context of a bacterial infection and act interdependently, orchestrating liver immune responses and return to homeostasis, respectively.", "title": "Liver-resident macrophage necroptosis orchestrates type 1 microbicidal inflammation and type-2-mediated tissue repair during bacterial infection." }, { "docid": "5785219", "text": "Nitric oxide (NO) is a product of L-arginine metabolism that suppresses cellular oxidative metabolism through the inhibition of tricarboxylic acid cycle and electron transport chain enzymes. The impact of NO synthase (NOS) activity on specific pathways of glucose metabolism in freshly harvested and overnight-cultured rat resident peritoneal macrophages, at rest and after stimulation with zymosan, was investigated using radiolabeled glucose. NOS activity was modulated through the L-arginine concentration in culture media and the use of its specific inhibitor, NG-monomethyl-L-arginine, and quantitated using radiolabeled L-arginine. Results demonstrated that NOS activity was associated with increased glucose disappearance, glycolysis, and hexose monophosphate shunt activity and, in line with the known inhibition of oxidative metabolism associated with the production of NO, with a decrease in the flux of glucose and butyrate carbon through the tricarboxylic acid cycle. In addition, the relative increase in glucose utilization that follows zymosan stimulation was enhanced by treatments that suppressed NOS activity. These results demonstrate that the characteristics of glucose metabolism by macrophages are, to a significant extent, determined by products of NOS.", "title": "Modulation of glucose metabolism in macrophages by products of nitric oxide synthase." } ]

[ { "docid": "56893404", "text": "Background Macrosomia is associated with considerable neonatal and maternal morbidity. Factors that predict macrosomia are poorly understood. The increased rate of macrosomia in the offspring of pregnant women with diabetes and in congenital hyperinsulinaemia is mediated by increased foetal insulin secretion. We assessed the in utero and neonatal role of two key regulators of pancreatic insulin secretion by studying birthweight and the incidence of neonatal hypoglycaemia in patients with heterozygous mutations in the maturity-onset diabetes of the young (MODY) genes HNF4A (encoding HNF-4α) and HNF1A/TCF1 (encoding HNF-1α), and the effect of pancreatic deletion of Hnf4a on foetal and neonatal insulin secretion in mice.", "title": "Macrosomia and Hyperinsulinaemic Hypoglycaemia in Patients with Heterozygous Mutations in the HNF4A Gene" } ]

[ { "docid": "9394119", "text": "IMPORTANCE Limited information about the relationship between specific mutations in BRCA1 or BRCA2 (BRCA1/2) and cancer risk exists. \n OBJECTIVE To identify mutation-specific cancer risks for carriers of BRCA1/2. \n DESIGN, SETTING, AND PARTICIPANTS Observational study of women who were ascertained between 1937 and 2011 (median, 1999) and found to carry disease-associated BRCA1 or BRCA2 mutations. The international sample comprised 19,581 carriers of BRCA1 mutations and 11,900 carriers of BRCA2 mutations from 55 centers in 33 countries on 6 continents. We estimated hazard ratios for breast and ovarian cancer based on mutation type, function, and nucleotide position. We also estimated RHR, the ratio of breast vs ovarian cancer hazard ratios. A value of RHR greater than 1 indicated elevated breast cancer risk; a value of RHR less than 1 indicated elevated ovarian cancer risk. EXPOSURES Mutations of BRCA1 or BRCA2. \n MAIN OUTCOMES AND MEASURES Breast and ovarian cancer risks. \n RESULTS Among BRCA1 mutation carriers, 9052 women (46%) were diagnosed with breast cancer, 2317 (12%) with ovarian cancer, 1041 (5%) with breast and ovarian cancer, and 7171 (37%) without cancer. Among BRCA2 mutation carriers, 6180 women (52%) were diagnosed with breast cancer, 682 (6%) with ovarian cancer, 272 (2%) with breast and ovarian cancer, and 4766 (40%) without cancer. In BRCA1, we identified 3 breast cancer cluster regions (BCCRs) located at c.179 to c.505 (BCCR1; RHR = 1.46; 95% CI, 1.22-1.74; P = 2 × 10(-6)), c.4328 to c.4945 (BCCR2; RHR = 1.34; 95% CI, 1.01-1.78; P = .04), and c. 5261 to c.5563 (BCCR2', RHR = 1.38; 95% CI, 1.22-1.55; P = 6 × 10(-9)). We also identified an ovarian cancer cluster region (OCCR) from c.1380 to c.4062 (approximately exon 11) with RHR = 0.62 (95% CI, 0.56-0.70; P = 9 × 10(-17)). In BRCA2, we observed multiple BCCRs spanning c.1 to c.596 (BCCR1; RHR = 1.71; 95% CI, 1.06-2.78; P = .03), c.772 to c.1806 (BCCR1'; RHR = 1.63; 95% CI, 1.10-2.40; P = .01), and c.7394 to c.8904 (BCCR2; RHR = 2.31; 95% CI, 1.69-3.16; P = .00002). We also identified 3 OCCRs: the first (OCCR1) spanned c.3249 to c.5681 that was adjacent to c.5946delT (6174delT; RHR = 0.51; 95% CI, 0.44-0.60; P = 6 × 10(-17)). The second OCCR spanned c.6645 to c.7471 (OCCR2; RHR = 0.57; 95% CI, 0.41-0.80; P = .001). Mutations conferring nonsense-mediated decay were associated with differential breast or ovarian cancer risks and an earlier age of breast cancer diagnosis for both BRCA1 and BRCA2 mutation carriers. \n CONCLUSIONS AND RELEVANCE Breast and ovarian cancer risks varied by type and location of BRCA1/2 mutations. With appropriate validation, these data may have implications for risk assessment and cancer prevention decision making for carriers of BRCA1 and BRCA2 mutations.", "title": "Association of type and location of BRCA1 and BRCA2 mutations with risk of breast and ovarian cancer." }, { "docid": "8892905", "text": "Alzheimer's disease (AD) is hypothesized to be caused by an overproduction or reduced clearance of amyloid-β (Aβ) peptide. Autosomal dominant AD (ADAD) caused by mutations in the presenilin (PSEN) gene have been postulated to result from increased production of Aβ42 compared to Aβ40 in the central nervous system (CNS). This has been demonstrated in rodent models of ADAD but not in human mutation carriers. We used compartmental modeling of stable isotope labeling kinetic (SILK) studies in human carriers of PSEN mutations and related noncarriers to evaluate the pathophysiological effects of PSEN1 and PSEN2 mutations on the production and turnover of Aβ isoforms. We compared these findings by mutation status and amount of fibrillar amyloid deposition as measured by positron emission tomography (PET) using the amyloid tracer Pittsburgh compound B (PIB). CNS Aβ42 to Aβ40 production rates were 24% higher in mutation carriers compared to noncarriers, and this was independent of fibrillar amyloid deposits quantified by PET PIB imaging. The fractional turnover rate of soluble Aβ42 relative to Aβ40 was 65% faster in mutation carriers and correlated with amyloid deposition, consistent with increased deposition of Aβ42 into plaques, leading to reduced recovery of Aβ42 in cerebrospinal fluid (CSF). Reversible exchange of Aβ42 peptides with preexisting unlabeled peptide was observed in the presence of plaques. These findings support the hypothesis that Aβ42 is overproduced in the CNS of humans with PSEN mutations that cause AD, and demonstrate that soluble Aβ42 turnover and exchange processes are altered in the presence of amyloid plaques, causing a reduction in Aβ42 concentrations in the CSF.", "title": "Increased in vivo amyloid-β42 production, exchange, and loss in presenilin mutation carriers." }, { "docid": "1387104", "text": "CONTEXT Venous thrombosis is a common complication in patients with cancer, leading to additional morbidity and compromising quality of life. \n OBJECTIVE To identify individuals with cancer with an increased thrombotic risk, evaluating different tumor sites, the presence of distant metastases, and carrier status of prothrombotic mutations. \n DESIGN, SETTING, AND PATIENTS A large population-based, case-control (Multiple Environmental and Genetic Assessment [MEGA] of risk factors for venous thrombosis) study of 3220 consecutive patients aged 18 to 70 years, with a first deep venous thrombosis of the leg or pulmonary embolism, between March 1, 1999, and May 31, 2002, at 6 anticoagulation clinics in the Netherlands, and separate 2131 control participants (partners of the patients) reported via a questionnaire on acquired risk factors for venous thrombosis. Three months after discontinuation of the anticoagulant therapy, all patients and controls were interviewed, a blood sample was taken, and DNA was isolated to ascertain the factor V Leiden and prothrombin 20210A mutations. \n MAIN OUTCOME MEASURE Risk of venous thrombosis. \n RESULTS The overall risk of venous thrombosis was increased 7-fold in patients with a malignancy (odds ratio [OR], 6.7; 95% confidence interval [CI], 5.2-8.6) vs persons without malignancy. Patients with hematological malignancies had the highest risk of venous thrombosis, adjusted for age and sex (adjusted OR, 28.0; 95% CI, 4.0-199.7), followed by lung cancer and gastrointestinal cancer. The risk of venous thrombosis was highest in the first few months after the diagnosis of malignancy (adjusted OR, 53.5; 95% CI, 8.6-334.3). Patients with cancer with distant metastases had a higher risk vs patients without distant metastases (adjusted OR, 19.8; 95% CI, 2.6-149.1). Carriers of the factor V Leiden mutation who also had cancer had a 12-fold increased risk vs individuals without cancer and factor V Leiden (adjusted OR, 12.1; 95% CI, 1.6-88.1). Similar results were indirectly calculated for the prothrombin 20210A mutation in patients with cancer. \n CONCLUSIONS Patients with cancer have a highly increased risk of venous thrombosis especially in the first few months after diagnosis and in the presence of distant metastases. Carriers of the factor V Leiden and prothrombin 20210A mutations appear to have an even higher risk.", "title": "Malignancies, prothrombotic mutations, and the risk of venous thrombosis." }, { "docid": "3285322", "text": "PURPOSE Mutations in the BRCA1 and BRCA2 genes confer greater risk of developing breast cancer. We determined whether tumor pathologic features and clinical features differ in patients with and without BRCA mutations. \n PATIENTS AND METHODS Tumor pathologic features and clinical characteristics were examined in 491 women with breast cancer who underwent genetic testing for BRCA mutations between 1997 and 2006. A retrospective review of medical records was conducted to determine clinical characteristics including ethnicity, age and clinical stage at diagnosis, age at parity, number of full-term pregnancies, use of oral contraceptives and hormone replacement therapy, and BRCA mutation status. Tumor pathology was reviewed to determine histologic type, tumor grade, and estrogen receptor, progesterone receptor, and HER-2/neu status. \n RESULTS Of the 491 patients with identified breast cancers, 391 patients were BRCA negative, and 86 patients were BRCA positive. Triple-negative breast cancer (ie, those with negative estrogen receptor, progesterone receptor, and HER-2/neu status) was diagnosed in 57.1% of the BRCA1-positive patients, 23.3% of the BRCA2-positive patients, and 13.8% of the BRCA-negative patients. BRCA1 mutation carriers had higher nuclear grade tumors than the other two groups (P < .001). Of the triple-negative cancer patients, BRCA2 mutation carriers were older when diagnosed than BRCA1 mutation carriers and noncarriers (P < .01). \n CONCLUSION These results suggest that tumors associated with BRCA1 mutations may be divided into two distinct groups, triple-negative and non-triple-negative groups. Future studies should seek to determine whether patients with BRCA1 mutations and triple-negative breast cancer respond to treatment better than BRCA-negative patients with similar tumor pathology.", "title": "Clinical and pathologic characteristics of patients with BRCA-positive and BRCA-negative breast cancer." }, { "docid": "8524891", "text": "OBJECTIVE White matter hyperintensities (WMHs) are areas of increased signal on T2-weighted magnetic resonance imaging (MRI) scans that most commonly reflect small vessel cerebrovascular disease. Increased WMH volume is associated with risk and progression of Alzheimer's disease (AD). These observations are typically interpreted as evidence that vascular abnormalities play an additive, independent role contributing to symptom presentation, but not core features of AD. We examined the severity and distribution of WMH in presymptomatic PSEN1, PSEN2, and APP mutation carriers to determine the extent to which WMH manifest in individuals genetically determined to develop AD. \n METHODS The study comprised participants (n = 299; age = 39.03 ± 10.13) from the Dominantly Inherited Alzheimer Network, including 184 (61.5%) with a mutation that results in AD and 115 (38.5%) first-degree relatives who were noncarrier controls. We calculated the estimated years from expected symptom onset (EYO) by subtracting the affected parent's symptom onset age from the participant's age. Baseline MRI data were analyzed for total and regional WMH. Mixed-effects piece-wise linear regression was used to examine WMH differences between carriers and noncarriers with respect to EYO. \n RESULTS Mutation carriers had greater total WMH volumes, which appeared to increase approximately 6 years before expected symptom onset. Effects were most prominent for the parietal and occipital lobe, which showed divergent effects as early as 22 years before estimated onset. \n INTERPRETATION Autosomal-dominant AD is associated with increased WMH well before expected symptom onset. The findings suggest the possibility that WMHs are a core feature of AD, a potential therapeutic target, and a factor that should be integrated into pathogenic models of the disease. Ann Neurol 2016;79:929-939.", "title": "White matter hyperintensities are a core feature of Alzheimer's disease: Evidence from the dominantly inherited Alzheimer network." }, { "docid": "24144677", "text": "Homozygous mutation in the ATM gene causes ataxia telangiectasia and heterozygous mutation carriers may be at increased risk of breast cancer. We studied a total of 22 ATM variants; 18 variants were analyzed in one of two large population-based studies from the U.S. and Poland, and four variants were analyzed in all 2,856 breast cancer cases and 3,344 controls from the two studies. The missense mutation Ser49Cys (c.146C>G, p. S49C), carried by approximately 2% of subjects, was more common in cases than controls in both study populations, combined odds ratio (OR) 1.69 (95% CI, 1.19-2.40; P=0.004). Another missense mutation at approximately 2% frequency, Phe858Leu (c.2572T>C, p. F858L), was associated with a significant increased risk in the U.S. study but not in Poland, and had a combined OR of 1.44 (95% CI, 0.98-2.11; P=0.06). These analyses provide the most convincing evidence thus far that missense mutations in ATM, particularly p. S49C, may be breast cancer susceptibility alleles. Because of their low frequency, even larger sample sizes are required to more firmly establish these associations.", "title": "The ATM missense mutation p.Ser49Cys (c.146C>G) and the risk of breast cancer." }, { "docid": "15648443", "text": "BACKGROUND Observational studies report reduced colorectal cancer in regular aspirin consumers. Randomised controlled trials have shown reduced risk of adenomas but none have employed prevention of colorectal cancer as a primary endpoint. The CAPP2 trial aimed to investigate the antineoplastic effects of aspirin and a resistant starch in carriers of Lynch syndrome, the major form of hereditary colorectal cancer; we now report long-term follow-up of participants randomly assigned to aspirin or placebo. \n METHODS In the CAPP2 randomised trial, carriers of Lynch syndrome were randomly assigned in a two-by-two factorial design to 600 mg aspirin or aspirin placebo or 30 g resistant starch or starch placebo, for up to 4 years. Randomisation was in blocks of 16 with provision for optional single-agent randomisation and extended postintervention double-blind follow-up; participants and investigators were masked to treatment allocation. The primary endpoint was development of colorectal cancer. Analysis was by intention to treat and per protocol. This trial is registered, ISRCTN59521990. \n RESULTS 861 participants were randomly assigned to aspirin or aspirin placebo. At a mean follow-up of 55·7 months, 48 participants had developed 53 primary colorectal cancers (18 of 427 randomly assigned to aspirin, 30 of 434 to aspirin placebo). Intention-to-treat analysis of time to first colorectal cancer showed a hazard ratio (HR) of 0·63 (95% CI 0·35-1·13, p=0·12). Poisson regression taking account of multiple primary events gave an incidence rate ratio (IRR) of 0·56 (95% CI 0·32-0·99, p=0·05). For participants completing 2 years of intervention (258 aspirin, 250 aspirin placebo), per-protocol analysis yielded an HR of 0·41 (0·19-0·86, p=0·02) and an IRR of 0·37 (0·18-0·78, p=0·008). No data for adverse events were available postintervention; during the intervention, adverse events did not differ between aspirin and placebo groups. \n INTERPRETATION 600 mg aspirin per day for a mean of 25 months substantially reduced cancer incidence after 55·7 months in carriers of hereditary colorectal cancer. Further studies are needed to establish the optimum dose and duration of aspirin treatment. \n FUNDING European Union; Cancer Research UK; Bayer Corporation; National Starch and Chemical Co; UK Medical Research Council; Newcastle Hospitals trustees; Cancer Council of Victoria Australia; THRIPP South Africa; The Finnish Cancer Foundation; SIAK Switzerland; Bayer Pharma.", "title": "Long-term effect of aspirin on cancer risk in carriers of hereditary colorectal cancer: an analysis from the CAPP2 randomised controlled trial" }, { "docid": "20280410", "text": "Inherited mutations in the gene BRCA2 predispose carriers to early onset breast cancer, but such mutations account for fewer than 2% of all cases in East Anglia. It is likely that low penetrance alleles explain the greater part of inherited susceptibility to breast cancer; polymorphic variants in strongly predisposing genes, such as BRCA2, are candidates for this role. BRCA2 is thought to be involved in DNA double strand break-repair. Few mice in which Brca2 is truncated survive to birth; of those that do, most are male, smaller than their normal littermates and have high cancer incidence. Here we show that a common human polymorphism (N372H) in exon 10 of BRCA2 confers an increased risk of breast cancer: the HH homozygotes have a 1.31-fold (95% CI, 1.07–1.61) greater risk than the NN group. Moreover, in normal female controls of all ages there is a significant deficiency of homozygotes compared with that expected from Hardy-Weinberg equilibrium, whereas in males there is an excess of homozygotes: the HH group has an estimated fitness of 0.82 in females and 1.38 in males. Therefore, this variant of BRCA2 appears also to affect fetal survival in a sex-dependent manner.", "title": "A common variant in BRCA2 is associated with both breast cancer risk and prenatal viability" }, { "docid": "13519661", "text": "Background Checkpoint kinase 2 (CHEK2) averts cancer development by promoting cell cycle arrest and activating DNA repair in genetically damaged cells. Previous investigation has established a role for the CHEK2 gene in breast cancer aetiology, but studies have largely been limited to the rare 1100delC mutation. Whether common polymorphisms in this gene influence breast cancer risk remains unknown. In this study, we aimed to assess the importance of common CHEK2 variants on population risk for breast cancer by capturing the majority of diversity in the gene using haplotype tagging single nucleotide polymorphisms (tagSNPs). Methods and Findings We analyzed 14 common SNPs spanning 52 kilobases (kb) of the CHEK2 gene in 92 Swedish women. Coverage evaluation indicated that these typed SNPs would efficiently convey association signal also from untyped SNPs in the same region. Six of the 14 SNPs predicted well both the haplotypic and single SNP variations within CHEK2. We genotyped these six tagSNPs in 1,577 postmenopausal breast cancer cases and 1,513 population controls, but found no convincing association between any common CHEK2 haplotype and breast cancer risk. The 1100delC mutation was rare in our Swedish population—0.7% in cases and 0.4% in controls— with a corresponding odds ratio for carriers versus noncarriers of 2.26 (95% confidence interval, 0.99–5.15). Estimates of the population frequency and the odds ratio of 1100delC indicate that our sample is representative of a Northern European population.", "title": "Linkage Disequilibrium Mapping of CHEK2: Common Variation and Breast Cancer Risk " }, { "docid": "1866911", "text": "Basal-like breast cancers arising in women carrying mutations in the BRCA1 gene, encoding the tumor suppressor protein BRCA1, are thought to develop from the mammary stem cell. To explore early cellular changes that occur in BRCA1 mutation carriers, we have prospectively isolated distinct epithelial subpopulations from normal mammary tissue and preneoplastic specimens from individuals heterozygous for a BRCA1 mutation. We describe three epithelial subsets including basal stem/progenitor, luminal progenitor and mature luminal cells. Unexpectedly, we found that breast tissue from BRCA1 mutation carriers harbors an expanded luminal progenitor population that shows factor-independent growth in vitro. Moreover, gene expression profiling revealed that breast tissue heterozygous for a BRCA1 mutation and basal breast tumors were more similar to normal luminal progenitor cells than any other subset, including the stem cell–enriched population. The c-KIT tyrosine kinase receptor (encoded by KIT) emerged as a key marker of luminal progenitor cells and was more highly expressed in BRCA1-associated preneoplastic tissue and tumors. Our findings suggest that an aberrant luminal progenitor population is a target for transformation in BRCA1-associated basal tumors .", "title": "Aberrant luminal progenitors as the candidate target population for basal tumor development in BRCA1 mutation carriers" }, { "docid": "2015126", "text": "The management of women who have a genetic predisposition for breast cancer requires careful planning. Women who have BRCA 1 and BRCA 2 mutations are at increased risk for breast cancer and for other cancers as well, particularly ovarian cancer. Screening, prophlyactic surgery, and chemoprevention are commonly utilized strategies in the management of these patients, and women may choose more than one of these strategies. No randomized prospective trials have assessed the impact of these strategies specifically in mutation carriers. All patients should be informed that screening, prophylactic surgery, and chemoprevention have the potential for harm as well as benefit.", "title": "Management of women who have a genetic predisposition for breast cancer." }, { "docid": "27449472", "text": "The metabolic syndrome was initially described as an insulin-resistance syndrome characterized by the clustering of metabolic traits such as high triglycerides, low high-density lipoprotein cholesterol, high blood pressure, abdominal obesity and different degrees of impaired glucose regulation. Although different definitions have been developed by various consensus groups, epidemiological studies demonstrate that they all associate the metabolic syndrome with a similar cardiometabolic risk, which is high for diabetes (ranging between three- and 20-fold), depending on the number of components and the inclusion of impaired fasting glucose, impaired glucose tolerance or both. The latter appear to indicate the failure of the beta cell to produce enough insulin to compensate for the increased demand due to insulin resistance. There is a hyperbolic relationship between insulin production and insulin sensitivity, which can be calculated by the disposition index. When this is altered there is a higher risk of developing Type 2 diabetes. There have been no clinical trials in subjects selected by the diagnosis of metabolic syndrome, but structured lifestyle changes have been tested in people with impaired fasting glucose/impaired glucose tolerance and have been able to reduce incident Type 2 diabetes by almost 50%, as long as a weight loss of at least 5% is achieved. Oral antidiabetic and anti-obesity drugs have also been successful to a lesser degree. Some fibrates have reduced or delayed incident diabetes. Extended-release niacin has a neutral effect and statins are controversial. ACE inhibitors and ARBs are the antihypertensive agents least associated with incident diabetes.", "title": "Metabolic syndrome as a risk factor for diabetes." }, { "docid": "13619127", "text": "OBJECTIVE To assess the risks of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia in patients with type 2 diabetes associated with prescribed diabetes drugs, particularly newer agents including gliptins or glitazones (thiazolidinediones). \n DESIGN Open cohort study in primary care. \n SETTING 1243 practices contributing data to the QResearch database in England. \n PARTICIPANTS 469,688 patients with type 2 diabetes aged 25-84 years between 1 April 2007 and 31 January 2015. EXPOSURES Hypoglycaemic agents (glitazones, gliptins, metformin, sulphonylureas, insulin, and other) alone and in combination. \n MAIN OUTCOME MEASURES First recorded diagnoses of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia recorded on patients' primary care, mortality, or hospital records. Cox models estimated hazard ratios for diabetes treatments adjusting for potential confounders. \n RESULTS 21,308 (4.5%) and 32,533 (6.9%) patients received prescriptions for glitazones and gliptins during follow-up, respectively. Compared with non-use, glitazones were associated with a decreased risk of blindness (adjusted hazard ratio 0.71, 95% confidence interval 0.57 to 0.89; rate 14.4 per 10,000 person years of exposure) and an increased risk of hypoglycaemia (1.22, 1.10 to 1.37; 65.1); gliptins were associated with a decreased risk of hypoglycaemia (0.86, 0.77 to 0.96; 45.8). Although the numbers of patients prescribed gliptin monotherapy or glitazones monotherapy were relatively low, there were significantly increased risks of severe kidney failure compared with metformin monotherapy (adjusted hazard ratio 2.55, 95% confidence interval 1.13 to 5.74). We found significantly lower risks of hyperglycaemia among patients prescribed dual therapy involving metformin with either gliptins (0.78, 0.62 to 0.97) or glitazones (0.60, 0.45 to 0.80) compared with metformin monotherapy. Patients prescribed triple therapy with metformin, sulphonylureas, and either gliptins (adjusted hazard ratio 5.07, 95% confidence interval 4.28 to 6.00) or glitazones (6.32, 5.35 to 7.45) had significantly higher risks of hypoglycaemia than those prescribed metformin monotherapy, but these risks were similar to those involving dual therapy with metformin and sulphonylureas (6.03, 5.47 to 6.63). Patients prescribed triple therapy with metformin, sulphonylureas, and glitazones had a significantly reduced risk of blindness compared with metformin monotherapy (0.67, 0.48 to 0.94). \n CONCLUSIONS We have found lower risks of hyperglycaemia among patients prescribed dual therapy involving metformin with either gliptins or glitazones compared with metformin alone. Compared with metformin monotherapy, triple therapy with metformin, sulphonylureas, and either gliptins or glitazones was associated with an increased risk of hypoglycaemia, which was similar to the risk for dual therapy with metformin and sulphonylureas. Compared with metformin monotherapy, triple therapy with metformin, sulphonylureas, and glitazones was associated with a reduced risk of blindness. These results, while subject to residual confounding, could have implications for the prescribing of hypoglycaemic drugs.", "title": "Diabetes treatments and risk of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia: open cohort study in primary care" }, { "docid": "857189", "text": "The protein cytotoxic T lymphocyte antigen-4 (CTLA-4) is an essential negative regulator of immune responses, and its loss causes fatal autoimmunity in mice. We studied a large family in which five individuals presented with a complex, autosomal dominant immune dysregulation syndrome characterized by hypogammaglobulinemia, recurrent infections and multiple autoimmune clinical features. We identified a heterozygous nonsense mutation in exon 1 of CTLA4. Screening of 71 unrelated patients with comparable clinical phenotypes identified five additional families (nine individuals) with previously undescribed splice site and missense mutations in CTLA4. Clinical penetrance was incomplete (eight adults of a total of 19 genetically proven CTLA4 mutation carriers were considered unaffected). However, CTLA-4 protein expression was decreased in regulatory T cells (Treg cells) in both patients and carriers with CTLA4 mutations. Whereas Treg cells were generally present at elevated numbers in these individuals, their suppressive function, CTLA-4 ligand binding and transendocytosis of CD80 were impaired. Mutations in CTLA4 were also associated with decreased circulating B cell numbers. Taken together, mutations in CTLA4 resulting in CTLA-4 haploinsufficiency or impaired ligand binding result in disrupted T and B cell homeostasis and a complex immune dysregulation syndrome.", "title": "Autosomal dominant immune dysregulation syndrome in humans with CTLA4 mutations" }, { "docid": "19460822", "text": "When the food intake of organisms such as yeast and rodents is reduced (dietary restriction), they live longer than organisms fed a normal diet. A similar effect is seen when the activity of nutrient-sensing pathways is reduced by mutations or chemical inhibitors. In rodents, both dietary restriction and decreased nutrient-sensing pathway activity can lower the incidence of age-related loss of function and disease, including tumors and neurodegeneration. Dietary restriction also increases life span and protects against diabetes, cancer, and cardiovascular disease in rhesus monkeys, and in humans it causes changes that protect against these age-related pathologies. Tumors and diabetes are also uncommon in humans with mutations in the growth hormone receptor, and natural genetic variants in nutrient-sensing pathways are associated with increased human life span. Dietary restriction and reduced activity of nutrient-sensing pathways may thus slow aging by similar mechanisms, which have been conserved during evolution. We discuss these findings and their potential application to prevention of age-related disease and promotion of healthy aging in humans, and the challenge of possible negative side effects.", "title": "Extending healthy life span--from yeast to humans." }, { "docid": "11457219", "text": "Fumarase deficiency is a rare autosomal recessive inborn error of metabolism of the Krebs Tricarboxylic Acid cycle. A heavy neurological disease burden is imparted by fumarase deficiency, commonly manifesting as microcephaly, dystonia, global developmental delay, seizures, and lethality in the infantile period. Heterozygous carriers also carry an increased risk of developing hereditary leiomyomatosis and renal cell carcinoma. We describe a non-consanguineous family in whom a dichorionic diamniotic twin pregnancy resulted in twin boys with fumarase deficiency proven at the biochemical, enzymatic, and molecular levels. Their clinical phenotype included hepatic involvement. A novel mutation in the fumarate hydratase gene was identified in this family.", "title": "Fumarase deficiency in dichorionic diamniotic twins." }, { "docid": "3847200", "text": "Direct induction of induced hepatocytes (iHeps) from fibroblasts holds potential as a strategy for regenerative medicine but until now has only been shown in culture settings. Here, we describe in vivo iHep formation using transcription factor induction and genetic fate tracing in mouse models of chronic liver disease. We show that ectopic expression of the transcription factors FOXA3, GATA4, HNF1A, and HNF4A from a polycistronic lentiviral vector converts mouse myofibroblasts into cells with a hepatocyte phenotype. In vivo expression of the same set of transcription factors from a p75 neurotrophin receptor peptide (p75NTRp)-tagged adenovirus enabled the generation of hepatocyte-like cells from myofibroblasts in fibrotic mouse livers and reduced liver fibrosis. We have therefore been able to convert pro-fibrogenic myofibroblasts in the liver into hepatocyte-like cells with positive functional benefits. This direct in vivo reprogramming approach may open new avenues for the treatment of chronic liver disease.", "title": "Direct Reprogramming of Hepatic Myofibroblasts into Hepatocytes In Vivo Attenuates Liver Fibrosis." }, { "docid": "30805636", "text": "BACKGROUND Recent studies have shown that type 2 diabetes is preventable by both lifestyle interventions and medications that influence primary glucose metabolism. Whether pharmacological interventions that influence primary lipid metabolism can also delay development of type 2 diabetes is unknown. The goal of this study was to evaluate the effect of the peroxisome proliferator-activated receptor ligand bezafibrate on the progression of impaired fasting glucose phase to type 2 diabetes in patients with coronary artery disease over a 6.2-year follow-up period. \n METHODS AND RESULTS The study sample comprised 303 nondiabetic patients 42 to 74 years of age with a fasting blood glucose level of 110 to 125 mg/dL (6.1 to 6.9 mmol/L). The patients received either 400 mg bezafibrate retard (156 patients) or placebo (147 patients) once a day. No patients were using statins, and use of ACE inhibitors, which also reduce diabetes incidence, was relatively low. During follow-up, development of new-onset diabetes was recorded in 146 patients: in 80 (54.4%) from the placebo group and 66 (42.3%) from the bezafibrate group (P=0.04). The mean time until onset of new diabetes was significantly delayed in patients on bezafibrate compared with patients on placebo: 4.6+/-2.3 versus 3.8+/-2.6 years (P=0.004). Multivariate analysis identified bezafibrate treatment as an independent predictor of reduced risk of new diabetes development (hazard ratio, 0.70; 95% CI, 0.49 to 0.99). Other significant variables associated with future overt type 2 diabetes in patients with impaired fasting glucose were total cholesterol level (hazard ratio, 1.22; 95% CI 1.0 to 1.51) and body mass index (hazard ratio, 1.10; 95% CI, 1.05 to 1.16). \n CONCLUSIONS Bezafibrate reduces the incidence and delays the onset of type 2 diabetes in patients with impaired fasting glucose. Whether the combination of bezafibrate with other recommended drugs for secondary prevention (statins and ACE inhibitors) would be as efficacious as suggested by our results remains to be determined.", "title": "Peroxisome proliferator-activated receptor ligand bezafibrate for prevention of type 2 diabetes mellitus in patients with coronary artery disease." }, { "docid": "5698494", "text": "OBJECTIVES To investigate whether statins reduce all cause mortality and major coronary and cerebrovascular events in people without established cardiovascular disease but with cardiovascular risk factors, and whether these effects are similar in men and women, in young and older (>65 years) people, and in people with diabetes mellitus. \n DESIGN Meta-analysis of randomised trials. \n DATA SOURCES Cochrane controlled trials register, Embase, and Medline. Data abstraction Two independent investigators identified studies on the clinical effects of statins compared with a placebo or control group and with follow-up of at least one year, at least 80% or more participants without established cardiovascular disease, and outcome data on mortality and major cardiovascular disease events. Heterogeneity was assessed using the Q and I(2) statistics. Publication bias was assessed by visual examination of funnel plots and the Egger regression test. \n RESULTS 10 trials enrolled a total of 70 388 people, of whom 23 681 (34%) were women and 16 078 (23%) had diabetes mellitus. Mean follow-up was 4.1 years. Treatment with statins significantly reduced the risk of all cause mortality (odds ratio 0.88, 95% confidence interval 0.81 to 0.96), major coronary events (0.70, 0.61 to 0.81), and major cerebrovascular events (0.81, 0.71 to 0.93). No evidence of an increased risk of cancer was observed. There was no significant heterogeneity of the treatment effect in clinical subgroups. \n CONCLUSION In patients without established cardiovascular disease but with cardiovascular risk factors, statin use was associated with significantly improved survival and large reductions in the risk of major cardiovascular events.", "title": "The benefits of statins in people without established cardiovascular disease but with cardiovascular risk factors: meta-analysis of randomised controlled trials" } ]

[ { "docid": "4388470", "text": "In the mammalian model of sex determination, embryos are considered to be sexually indifferent until the transient action of a sex-determining gene initiates gonadal differentiation. Although this model is thought to apply to all vertebrates, this has yet to be established. Here we have examined three lateral gynandromorph chickens (a rare, naturally occurring phenomenon in which one side of the animal appears male and the other female) to investigate the sex-determining mechanism in birds. These studies demonstrated that gynandromorph birds are genuine male:female chimaeras, and indicated that male and female avian somatic cells may have an inherent sex identity. To test this hypothesis, we transplanted presumptive mesoderm between embryos of reciprocal sexes to generate embryos containing male:female chimaeric gonads. In contrast to the outcome for mammalian mixed-sex chimaeras, in chicken mixed-sex chimaeras the donor cells were excluded from the functional structures of the host gonad. In an example where female tissue was transplanted into a male host, donor cells contributing to the developing testis retained a female identity and expressed a marker of female function. Our study demonstrates that avian somatic cells possess an inherent sex identity and that, in birds, sexual differentiation is substantively cell autonomous.", "title": "Somatic sex identity is cell-autonomous in the chicken" } ]

[ { "docid": "5597586", "text": "OBJECTIVES Patients with AL amyloidosis can benefit from high-dose chemotherapy and autologous stem cell transplantation (ASCT). Transplantation can be challenging due to fluid shifts, sepsis, and cardiac dysrhythmias. Amyloidosis may present with autonomic neuropathy (AN) that renders peritransplant care problematic. The purpose of this study was to determine the outcome of patients with AN during and after ASCT. \n METHODS We performed a case-control study of patients with AL amyloidosis with associated AN and compared them to a large matched cohort without AN who also underwent ASCT. \n RESULTS We identified 13 patients with AN who underwent ASCT and a matched control group of 95 patients without AN. Patients with AN had more organs involved (median 2.5 vs 1, p < 0.001) and the conditioning dose of melphalan was often reduced by 30% compared to controls without AN (p = 0.0015). Median duration of hospitalization was similar for both cohorts, as were engraftment kinetics. Atrial fibrillation occurred in all patients with AN but in only 1 control patient (p < 0.0001). Median overall survival (OS) for patients with AN was 29 months but >60 months for controls (p < 0.0001). On univariate analysis, cardiac involvement (p = 0.0132), AN (p = 0.0011), glomerular filtration rate (p = 0.038), number of organs involved (p = 0.0064), and NT-pro-BNP (p = 0.039) all had an impact on OS. On multivariate analysis, AN retained an independent adverse impact on OS. \n CONCLUSIONS Patients with autonomic neuropathy secondary to AL amyloidosis can undergo autologous stem cell transplantation with relative safety. Autonomic neuropathy is an independent, adverse determinant of survival in these patients.", "title": "Stem cell transplantation in patients with autonomic neuropathy due to primary (AL) amyloidosis." }, { "docid": "18949516", "text": "Reproductive cessation is perhaps the earliest aging phenotype that humans experience. Similarly, reproduction of Caenorhabditis elegans ceases in mid-adulthood. Although somatic aging has been studied in both worms and humans, mechanisms regulating reproductive aging are not yet understood. Here, we show that TGF-β Sma/Mab and Insulin/IGF-1 signaling regulate C. elegans reproductive aging by modulating multiple aspects of the reproductive process, including embryo integrity, oocyte fertilizability, chromosome segregation fidelity, DNA damage resistance, and oocyte and germline morphology. TGF-β activity regulates reproductive span and germline/oocyte quality noncell-autonomously and is temporally and transcriptionally separable from its regulation of growth. Chromosome segregation, cell cycle, and DNA damage response genes are upregulated in TGF-β mutant oocytes, decline in aged mammalian oocytes, and are critical for oocyte quality maintenance. Our data suggest that C. elegans and humans share many aspects of reproductive aging, including the correlation between reproductive aging and declining oocyte quality and mechanisms determining oocyte quality.", "title": "TGF-β and Insulin Signaling Regulate Reproductive Aging via Oocyte and Germline Quality Maintenance" }, { "docid": "36708463", "text": "A major question is whether genes encoded on the sex chromosomes act directly in non-gonadal tissues to cause sex differences in development or function, or whether all sex differences in somatic tissues are induced by gonadal secretions. As part of this question we asked whether mouse X-Y homologous gene pairs are expressed in brain in a sex-specific fashion. Using RT-PCR and northern blot analysis, we assessed mRNA expression in brain of eight Y-linked genes as well as their X-linked homologues, at three ages: 13.5 days post coitum, the day of birth (P1) and adult. Transcripts of six Y genes were expressed at one or more ages: Usp9y, Ube1y, Smcy, Eif2s3y, Uty and Dby. Their expression also occurred in XY female brain, and therefore does not require testicular secretions. Six X-linked homologues (Usp9x, Ube1x, Smcx, Eif2s3x, Utx and Dbx) were also expressed in brain, and in adulthood all of these transcripts were expressed at significantly higher levels in brains of females than in brains of males, irrespective of their X-inactivation status. For five of these gene pairs, the expression of the Y-linked homologue in males was not sufficient to compensate for the female bias in X gene expression. Three X-Y gene pairs, Usp9x/y, Ube1x/y and Eif2s3x/y, appeared to be differentially regulated (expressed in brain in a different age- or tissue-dependent pattern), and hence may not be functionally equivalent. These sex differences in X-Y gene expression suggest several mechanisms by which these genes may participate in sex differences in brain development and function.", "title": "Sex differences in sex chromosome gene expression in mouse brain." }, { "docid": "22490293", "text": "Although it has now been 10 years since the first cloned mammals were generated from somatic cells using nuclear transfer (NT), most cloned embryos usually undergo developmental arrest prior to or soon after implantation, and the success rate for producing live offspring by cloning remains below 5%. The low success rate is believed to be associated with epigenetic errors, including abnormal DNA hypermethylation, but the mechanism of \"reprogramming\" is unclear. We have been able to develop a stable NT method in the mouse in which donor nuclei are directly injected into the oocyte using a piezo-actuated micromanipulator. Especially in the mouse, only a few laboratories can make clones from adult somatic cells, and cloned mice are never successfully produced from most mouse strains. However, this technique promises to be an important tool for future research in basic biology. For example, NT can be used to generate embryonic stem (NT-ES) cell lines from a patient's own somatic cells. We have shown that NT-ES cells are equivalent to ES cells derived from fertilized embryos and that they can be generated relatively easily from a variety of mouse genotypes and cell types of both sexes, even though it may be more difficult to generate clones directly. In general, NT-ES cell techniques are expected to be applied to regenerative medicine; however, this technique can also be applied to the preservation of genetic resources of mouse strain instead of embryos, oocytes and spermatozoa. This review describes how to improve cloning efficiency and NT-ES cell establishment and further applications.", "title": "Production of cloned mice and ES cells from adult somatic cells by nuclear transfer: how to improve cloning efficiency?" }, { "docid": "41380943", "text": "During embryonic development, gonadal steroid hormones (androgens and estrogens) are thought to organize the sexual differentiation of the brain in the heterogametic sexes of higher vertebrates (males in mammals, females in birds). Brain differentiation of the homogametic sexes is thought to proceed by default, not requiring sex hormones for sex-specific organization. In gallinaceous birds such as the Japanese quail, female brain organization is thought to develop via estrogen-dependent demasculinization of a default male brain phenotype. We performed male donor-to-female host (MF), female-to-male (FM), male-to-male (MM), and female-to-female (FF) isotopic, isochronic transplantation of the forebrain primordium in Japanese quail embryos before gonadal differentiation had occurred; brain chimeras had a forebrain (including the hypothalamus) originating exclusively from donor cells. MM, FF, and MF chimeras all showed sexual behavior governed by the genetic sex of the host. In contrast, FM chimeras (genetically female forebrain, all other tissues genetically male) showed no mounting and only rudimentary crowing behavior. Although MM, FF, MF, and FM chimeras all showed host-typical production of steroid hormones during embryonic life, only FM chimeras were hypogonadal, had atypical low levels of circulating testosterone in adulthood, and showed reduction (crowing) or absence (mounting) of reproductive behaviors. Morphological features of the medial preoptic nucleus (a sexually dimorphic brain area) also were not male-like in FM males. These data demonstrate a brain-intrinsic, genetically determined component that organizes the sex-typical production of gonadal hormones in adulthood and call for a reevaluation of the mechanisms underlying brain sexual differentiation in other higher-vertebrate species.", "title": "Male Japanese quails with female brains do not show male sexual behaviors." }, { "docid": "13702924", "text": "Mosquitoes are vectors of a number of important human and animal diseases. The development of novel vector control strategies requires a thorough understanding of mosquito biology. To facilitate this, we used RNA-seq to identify novel genes and provide the first high-resolution view of the transcriptome throughout development and in response to blood feeding in a mosquito vector of human disease, Aedes aegypti, the primary vector for Dengue and yellow fever. We characterized mRNA expression at 34 distinct time points throughout Aedes development, including adult somatic and germline tissues, by using polyA+ RNA-seq. We identify a total of 14,238 novel new transcribed regions corresponding to 12,597 new loci, as well as many novel transcript isoforms of previously annotated genes. Altogether these results increase the annotated fraction of the transcribed genome into long polyA+ RNAs by more than twofold. We also identified a number of patterns of shared gene expression, as well as genes and/or exons expressed sex-specifically or sex-differentially. Expression profiles of small RNAs in ovaries, early embryos, testes, and adult male and female somatic tissues also were determined, resulting in the identification of 38 new Aedes-specific miRNAs, and ~291,000 small RNA new transcribed regions, many of which are likely to be endogenous small-interfering RNAs and Piwi-interacting RNAs. Genes of potential interest for transgene-based vector control strategies also are highlighted. Our data have been incorporated into a user-friendly genome browser located at www. Aedes.caltech.edu, with relevant links to Vectorbase (www.vectorbase.org).", "title": "The Developmental Transcriptome of the Mosquito Aedes aegypti, an Invasive Species and Major Arbovirus Vector" }, { "docid": "4423327", "text": "Nanog is a divergent homeodomain protein found in mammalian pluripotent cells and developing germ cells. Deletion of Nanog causes early embryonic lethality, whereas constitutive expression enables autonomous self-renewal of embryonic stem cells. Nanog is accordingly considered a core element of the pluripotent transcriptional network. However, here we report that Nanog fluctuates in mouse embryonic stem cells. Transient downregulation of Nanog appears to predispose cells towards differentiation but does not mark commitment. By genetic deletion we show that, although they are prone to differentiate, embryonic stem cells can self-renew indefinitely in the permanent absence of Nanog. Expanded Nanog null cells colonize embryonic germ layers and exhibit multilineage differentiation both in fetal and adult chimaeras. Although they are also recruited to the germ line, primordial germ cells lacking Nanog fail to mature on reaching the genital ridge. This defect is rescued by repair of the mutant allele. Thus Nanog is dispensible for expression of somatic pluripotency but is specifically required for formation of germ cells. Nanog therefore acts primarily in construction of inner cell mass and germ cell states rather than in the housekeeping machinery of pluripotency. We surmise that Nanog stabilizes embryonic stem cells in culture by resisting or reversing alternative gene expression states.", "title": "Nanog safeguards pluripotency and mediates germline development" }, { "docid": "12232678", "text": "Recent reports have suggested that birds lack a mechanism of wholesale dosage compensation for the Z sex chromosome. This discovery was rather unexpected, as all other animals investigated with chromosomal mechanisms of sex determination have some method to counteract the effects of gene dosage of the dominant sex chromosome in males and females. Despite the lack of a global mechanism of avian dosage compensation, the pattern of gene expression difference between males and females varies a great deal for individual Z-linked genes. This suggests that some genes may be individually dosage compensated, and that some less-than-global pattern of dosage compensation, such as local or temporal, exists on the avian Z chromosome. We used global gene expression profiling in males and females for both somatic and gonadal tissue at several time points in the life cycle of the chicken to assess the pattern of sex-biased gene expression on the Z chromosome. Average fold-change between males and females varied somewhat among tissue time-point combinations, with embryonic brain samples having the smallest gene dosage effects, and adult gonadal tissue having the largest degree of male bias. Overall, there were no neighborhoods of overall dosage compensation along the Z. Taken together, this suggests that dosage compensation is regulated on the Z chromosome entirely on a gene-by-gene level, and can vary during the life cycle and by tissue type. This regulation may be an indication of how critical a given gene's functionality is, as the expression level for essential genes will be tightly regulated in order to avoid perturbing important pathways and networks with differential expression levels in males and females.", "title": "All dosage compensation is local: Gene-by-gene regulation of sex-biased expression on the chicken Z chromosome" }, { "docid": "31882215", "text": "We describe robust induction of autophagy during the reprogramming of mouse fibroblasts to induced pluripotent stem cells by four reprogramming factors (Sox2, Oct4, Klf4 and c-Myc), henceforth 4F. This process occurs independently of p53 activation, and is mediated by the synergistic downregulation of mechanistic target of rapamycin complex 1 (mTORC1) and the induction of autophagy-related genes. The 4F coordinately repress mTORC1, but bifurcate in their regulation of autophagy-related genes, with Klf4 and c-Myc inducing them but Sox2 and Oct4 inhibiting them. On one hand, inhibition of mTORC1 facilitates reprogramming by promoting cell reshaping (mitochondrial remodelling and cell size reduction). On the other hand, mTORC1 paradoxically impairs reprogramming by triggering autophagy. Autophagy does not participate in cell reshaping in reprogramming but instead degrades p62, whose accumulation in autophagy-deficient cells facilitates reprogramming. Our results thus reveal a complex signalling network involving mTORC1 inhibition and autophagy induction in the early phase of reprogramming, whose delicate balance ultimately determines reprogramming efficiency.", "title": "Autophagy and mTORC1 regulate the stochastic phase of somatic cell reprogramming" }, { "docid": "15803282", "text": "The extremely low efficiency of human embryonic stem cell (hESC) derivation using somatic cell nuclear transfer (SCNT) limits its potential application. Blastocyst formation from human SCNT embryos occurs at a low rate and with only some oocyte donors. We previously showed in mice that reduction of histone H3 lysine 9 trimethylation (H3K9me3) through ectopic expression of the H3K9me3 demethylase Kdm4d greatly improves SCNT embryo development. Here we show that overexpression of a related H3K9me3 demethylase KDM4A improves human SCNT, and that, as in mice, H3K9me3 in the human somatic cell genome is an SCNT reprogramming barrier. Overexpression of KDM4A significantly improves the blastocyst formation rate in human SCNT embryos by facilitating transcriptional reprogramming, allowing efficient derivation of SCNT-derived ESCs using adult Age-related Macular Degeneration (AMD) patient somatic nuclei donors. This conserved mechanistic insight has potential applications for improving SCNT in a variety of contexts, including regenerative medicine.", "title": "Histone Demethylase Expression Enhances Human Somatic Cell Nuclear Transfer Efficiency and Promotes Derivation of Pluripotent Stem Cells." }, { "docid": "17844478", "text": "It is established that tumor cell-derived VEGF acts on endothelial cells to promote angiogenesis and tumor growth. Here, we demonstrate that in K5-SOS-dependent mouse skin tumors, autocrine VEGF is required for tumor cell proliferation in a cell-autonomous and angiogenesis-independent manner. VEGF is upregulated in SOS-expressing tumors, and its deletion in epidermal cells delays tumorigenesis by suppressing angiogenesis and tumor cell proliferation. Epidermis-specific Flt1 deletion also impairs tumorigenesis and proliferation. Surprisingly, complete tumor inhibition occurs in the absence of VEGF in EGFR mutant mice, demonstrating that VEGFR and EGFR synergize in neoplastic cells to promote tumor growth. Mechanistically, K5-SOS upregulates VEGF, Flt1, and Neuropilin-1 in an Erk-dependent manner, thereby activating an autocrine proliferation loop, whereas EGFR prevents tumor cells from apoptosis. Moreover, Flt1 is upregulated in human SCC, and its inhibition in SCC cells impairs proliferation. Thus, in addition to regulating angiogenesis, VEGF has to be considered as a potent growth factor for epidermal tumors.", "title": "Autocrine VEGF Signaling Synergizes with EGFR in Tumor Cells to Promote Epithelial Cancer Development" }, { "docid": "7426741", "text": "Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) resets the epigenome to an embryonic-like state. Vitamin C enhances the reprogramming process, but the underlying mechanisms are unclear. Here we show that the histone demethylases Jhdm1a/1b are key effectors of somatic cell reprogramming downstream of vitamin C. We first observed that vitamin C induces H3K36me2/3 demethylation in mouse embryonic fibroblasts in culture and during reprogramming. We then identified Jhdm1a/1b, two known vitamin-C-dependent H3K36 demethylases, as potent regulators of reprogramming through gain- and loss-of-function approaches. Furthermore, we found that Jhdm1b accelerates cell cycle progression and suppresses cell senescence during reprogramming by repressing the Ink4/Arf locus. Jhdm1b also cooperates with Oct4 to activate the microRNA cluster 302/367, an integral component of the pluripotency machinery. Our results therefore reveal a role for H3K36me2/3 in cell fate determination and establish a link between histone demethylases and vitamin-C-induced reprogramming.", "title": "The histone demethylases Jhdm1a/1b enhance somatic cell reprogramming in a vitamin-C-dependent manner." }, { "docid": "4405194", "text": "Somatic cell nuclear transfer, cell fusion, or expression of lineage-specific factors have been shown to induce cell-fate changes in diverse somatic cell types. We recently observed that forced expression of a combination of three transcription factors, Brn2 (also known as Pou3f2), Ascl1 and Myt1l, can efficiently convert mouse fibroblasts into functional induced neuronal (iN) cells. Here we show that the same three factors can generate functional neurons from human pluripotent stem cells as early as 6 days after transgene activation. When combined with the basic helix-loop-helix transcription factor NeuroD1, these factors could also convert fetal and postnatal human fibroblasts into iN cells showing typical neuronal morphologies and expressing multiple neuronal markers, even after downregulation of the exogenous transcription factors. Importantly, the vast majority of human iN cells were able to generate action potentials and many matured to receive synaptic contacts when co-cultured with primary mouse cortical neurons. Our data demonstrate that non-neural human somatic cells, as well as pluripotent stem cells, can be converted directly into neurons by lineage-determining transcription factors. These methods may facilitate robust generation of patient-specific human neurons for in vitro disease modelling or future applications in regenerative medicine.", "title": "Induction of human neuronal cells by defined transcription factors" }, { "docid": "21380232", "text": "Mouse embryos undergo genome-wide methylation reprogramming by demethylation in early preimplantation development, followed by remethylation thereafter. Here we show that genome-wide reprogramming is conserved in several mammalian species and ask whether it also occurs in embryos cloned with the use of highly methylated somatic donor nuclei. Normal bovine, rat, and pig zygotes showed a demethylated paternal genome, suggesting active demethylation. In bovine embryos methylation was further reduced during cleavage up to the eight-cell stage, and this reduction in methylation was followed by de novo methylation by the 16-cell stage. In cloned one-cell embryos there was a reduction in methylation consistent with active demethylation, but no further demethylation occurred subsequently. Instead, de novo methylation and nuclear reorganization of methylation patterns resembling those of differentiated cells occurred precociously in many cloned embryos. Cloned, but not normal, morulae had highly methylated nuclei in all blastomeres that resembled those of the fibroblast donor cells. Our study shows that epigenetic reprogramming occurs aberrantly in most cloned embryos; incomplete reprogramming may contribute to the low efficiency of cloning.", "title": "Conservation of methylation reprogramming in mammalian development: aberrant reprogramming in cloned embryos." }, { "docid": "3823862", "text": "BackgroundBy comparing the quail genome with that of chicken, chromosome rearrangements that have occurred in these two galliform species over 35 million years of evolution can be detected. From a more practical point of view, the definition of conserved syntenies helps to predict the position of genes in quail, based on information taken from the chicken sequence, thus enhancing the utility of this species in biological studies through a better knowledge of its genome structure. A microsatellite and an Amplified Fragment Length Polymorphism (AFLP) genetic map were previously published for quail, as well as comparative cytogenetic data with chicken for macrochromosomes. Quail genomics will benefit from the extension and the integration of these maps. ResultsThe integrated linkage map presented here is based on segregation analysis of both anonymous markers and functional gene loci in 1,050 quail from three independent F2 populations. Ninety-two loci are resolved into 14 autosomal linkage groups and a Z chromosome-specific linkage group, aligned with the quail AFLP map. The size of linkage groups ranges from 7.8 cM to 274.8 cM. The total map distance covers 904.3 cM with an average spacing of 9.7 cM between loci. The coverage is not complete, as macrochromosome CJA08, the gonosome CJAW and 23 microchromosomes have no marker assigned yet. Significant sequence identities of quail markers with chicken enabled the alignment of the quail linkage groups on the chicken genome sequence assembly. This, together with interspecific Fluorescence In Situ Hybridization (FISH), revealed very high similarities in marker order between the two species for the eight macrochromosomes and the 14 microchromosomes studied. ConclusionIntegrating the two microsatellite and the AFLP quail genetic maps greatly enhances the quality of the resulting information and will thus facilitate the identification of Quantitative Trait Loci (QTL). The alignment with the chicken chromosomes confirms the high conservation of gene order that was expected between the two species for macrochromosomes. By extending the comparative study to the microchromosomes, we suggest that a wealth of information can be mined in chicken, to be used for genome analyses in quail.", "title": "Integrated maps in quail (Coturnix japonica) confirm the high degree of synteny conservation with chicken (Gallus gallus) despite 35 million years of divergence" }, { "docid": "5415832", "text": "Hematopoietic stem cells (HSCs) rely on instructive cues from the bone marrow (BM) niche to maintain their quiescence and adapt blood production to the organism's needs. Alterations in the BM niche are commonly observed in blood malignancies and directly contribute to the aberrant function of disease-initiating leukemic stem cells (LSCs). Here, we review recent insights into the cellular and molecular determinants of the normal HSC niche and describe how genetic changes in stromal cells and leukemia-induced BM niche remodeling contribute to blood malignancies. Moreover, we discuss how these findings can be applied to non-cell-autonomous therapies targeting the LSC niche.", "title": "Normal and leukemic stem cell niches: insights and therapeutic opportunities." }, { "docid": "6078882", "text": "It has been demonstrated for some cancers that the frequency of somatic oncogenic mutations may vary in ancestral populations. To determine whether key driver alterations might occur at different frequencies in colorectal cancer, we applied a high-throughput genotyping platform (OncoMap) to query 385 mutations across 33 known cancer genes in colorectal cancer DNA from 83 Asian, 149 Black and 195 White patients. We found that Asian patients had fewer canonical oncogenic mutations in the genes tested (60% vs Black 79% (P = 0.011) and White 77% (P = 0.015)), and that BRAF mutations occurred at a higher frequency in White patients (17% vs Asian 4% (P = 0.004) and Black 7% (P = 0.014)). These results suggest that the use of genomic approaches to elucidate the different ancestral determinants harbored by patient populations may help to more precisely and effectively treat colorectal cancer.", "title": "Colorectal Cancers from Distinct Ancestral Populations Show Variations in BRAF Mutation Frequency" }, { "docid": "6913227", "text": "Foxp3(+) T regulatory (Treg) cells prevent inflammatory disease but the mechanistic basis of suppression is not understood completely. Gene silencing by RNA interference can act in a cell-autonomous and non-cell-autonomous manner, providing mechanisms of intercellular regulation. Here, we demonstrate that non-cell-autonomous gene silencing, mediated by miRNA-containing exosomes, is a mechanism employed by Treg cells to suppress T-cell-mediated disease. Treg cells transferred microRNAs (miRNA) to various immune cells, including T helper 1 (Th1) cells, suppressing Th1 cell proliferation and cytokine secretion. Use of Dicer-deficient or Rab27a and Rab27b double-deficient Treg cells to disrupt miRNA biogenesis or the exosomal pathway, respectively, established a requirement for miRNAs and exosomes for Treg-cell-mediated suppression. Transcriptional analysis and miRNA inhibitor studies showed that exosome-mediated transfer of Let-7d from Treg cell to Th1 cells contributed to suppression and prevention of systemic disease. These studies reveal a mechanism of Treg-cell-mediated suppression mediated by miRNA-containing exosomes.", "title": "MicroRNA-Containing T-Regulatory-Cell-Derived Exosomes Suppress Pathogenic T Helper 1 Cells" }, { "docid": "464511", "text": "Genetically identical cells sharing an environment can display markedly different phenotypes. It is often unclear how much of this variation derives from chance, external signals, or attempts by individual cells to exert autonomous phenotypic programs. By observing thousands of cells for hundreds of consecutive generations under constant conditions, we dissect the stochastic decision between a solitary, motile state and a chained, sessile state in Bacillus subtilis. We show that the motile state is 'memoryless', exhibiting no autonomous control over the time spent in the state. In contrast, the time spent as connected chains of cells is tightly controlled, enforcing coordination among related cells in the multicellular state. We show that the three-protein regulatory circuit governing the decision is modular, as initiation and maintenance of chaining are genetically separable functions. As stimulation of the same initiating pathway triggers biofilm formation, we argue that autonomous timing allows a trial commitment to multicellularity that external signals could extend.", "title": "Memory and Modularity in Cell-Fate Decision Making" } ]

[ { "docid": "2212067", "text": "Circadian cycles and cell cycles are two fundamental periodic processes with a period in the range of 1 day. Consequently, coupling between such cycles can lead to synchronization. Here, we estimated the mutual interactions between the two oscillators by time-lapse imaging of single mammalian NIH3T3 fibroblasts during several days. The analysis of thousands of circadian cycles in dividing cells clearly indicated that both oscillators tick in a 1:1 mode-locked state, with cell divisions occurring tightly 5 h before the peak in circadian Rev-Erbα-YFP reporter expression. In principle, such synchrony may be caused by either unidirectional or bidirectional coupling. While gating of cell division by the circadian cycle has been most studied, our data combined with stochastic modeling unambiguously show that the reverse coupling is predominant in NIH3T3 cells. Moreover, temperature, genetic, and pharmacological perturbations showed that the two interacting cellular oscillators adopt a synchronized state that is highly robust over a wide range of parameters. These findings have implications for circadian function in proliferative tissues, including epidermis, immune cells, and cancer.", "title": "Robust synchronization of coupled circadian and cell cycle oscillators in single mammalian cells" }, { "docid": "10608822", "text": "Daily synchronous rhythms of cell division at the tissue or organism level are observed in many species and suggest that the circadian clock and cell cycle oscillators are coupled. For mammals, despite known mechanistic interactions, the effect of such coupling on clock and cell cycle progression, and hence its biological relevance, is not understood. In particular, we do not know how the temporal organization of cell division at the single-cell level produces this daily rhythm at the tissue level. Here we use multispectral imaging of single live cells, computational methods, and mathematical modeling to address this question in proliferating mouse fibroblasts. We show that in unsynchronized cells the cell cycle and circadian clock robustly phase lock each other in a 1:1 fashion so that in an expanding cell population the two oscillators oscillate in a synchronized way with a common frequency. Dexamethasone-induced synchronization reveals additional clock states. As well as the low-period phase-locked state there are distinct coexisting states with a significantly higher period clock. Cells transition to these states after dexamethasone synchronization. The temporal coordination of cell division by phase locking to the clock at a single-cell level has significant implications because disordered circadian function is increasingly being linked to the pathogenesis of many diseases, including cancer.", "title": "Phase locking and multiple oscillating attractors for the coupled mammalian clock and cell cycle." } ]

[ { "docid": "11557602", "text": "LXR alpha is a nuclear receptor that has previously been shown to regulate the metabolic conversion of cholesterol to bile acids. Here we define a role for this transcription factor in the control of cellular cholesterol efflux. We demonstrate that retroviral expression of LXR alpha in NIH 3T3 fibroblasts or RAW264.7 macrophages and/or treatment of these cells with oxysterol ligands of LXR results in 7- to 30-fold induction of the mRNA encoding the putative cholesterol/phospholipid transporter ATP-binding cassette (ABC)A1. In contrast, induction of ABCA1 mRNA in response to oxysterols is attenuated in cells that constitutively express dominant-negative forms of LXR alpha or LXR beta that lack the AF2 transcriptional activation domain. We further demonstrate that expression of LXR alpha in NIH 3T3 fibroblasts and/or treatment of these cells with oxysterols is sufficient to stimulate cholesterol efflux to extracellular apolipoprotein AI. The ability of oxysterol ligands of LXR to stimulate efflux is dramatically reduced in Tangier fibroblasts, which carry a loss of function mutation in the ABCA1 gene. Taken together, these results indicate that cellular cholesterol efflux is controlled, at least in part, at the level of transcription by a nuclear receptor-signaling pathway. They suggest a model in which activation of LXRs by oxysterols in response to cellular sterol loading leads to induction of the ABCA1 transporter and the stimulation of lipid efflux to extracellular acceptors. These findings have important implications for our understanding of mammalian cholesterol homeostasis and suggest new opportunities for pharmacological regulation of cellular lipid metabolism.", "title": "Control of cellular cholesterol efflux by the nuclear oxysterol receptor LXR alpha." }, { "docid": "14471161", "text": "Circadian disruption accelerates cancer progression, whereas circadian reinforcement could halt it. Mice with P03 pancreatic adenocarcinoma (n = 77) were synchronized and fed ad libitum (AL) or with meal timing (MT) from Zeitgeber time (ZT) 2 to ZT6 with normal or fat diet. Tumor gene expression profiling was determined with DNA microarrays at endogenous circadian time (CT) 4 and CT16. Circadian mRNA expression patterns were determined for clock genes Rev-erbalpha, Per2, and Bmal1, cellular stress genes Hspa8 and Cirbp, and cyclin A2 gene Ccna2 in liver and tumor. The 24-hour patterns in telemetered rest-activity and body temperature and plasma corticosterone and insulin-like growth factor-I (IGF-I) were assessed. We showed that MT inhibited cancer growth by approximately 40% as compared with AL (P = 0.011) irrespective of calorie intake. Clock gene transcription remained arrhythmic in tumors irrespective of feeding schedule or diet. Yet, MT upregulated or downregulated the expression of 423 tumor genes, according to CT. Moreover, 36 genes involved in cellular stress, cell cycle, and metabolism were upregulated at one CT and downregulated 12 h apart. MT induced >10-fold circadian expression of Hspa8, Cirbp, and Ccna2 in tumors. Corticosterone or IGF-I patterns played no role in tumor growth inhibition. In contrast, MT consistently doubled the circadian amplitude of body temperature. Peak and trough respectively corresponded to peak expressions of Hspa8 and Cirbp in tumors. The reinforcement of the host circadian timing system with MT induced 24-hour rhythmic expression of critical genes in clock-deficient tumors, which translated into cancer growth inhibition. Targeting circadian clocks represents a novel potential challenge for cancer therapeutics.", "title": "Cancer inhibition through circadian reprogramming of tumor transcriptome with meal timing." }, { "docid": "11565780", "text": "Synchronous oscillations of thousands of cellular clocks in the suprachiasmatic nucleus (SCN), the circadian centre, are coordinated by precisely timed cell-cell communication, the principle of which is largely unknown. Here we show that the amount of RGS16 (regulator of G protein signalling 16), a protein known to inactivate Gαi, increases at a selective circadian time to allow time-dependent activation of intracellular cyclic AMP signalling in the SCN. Gene ablation of Rgs16 leads to the loss of circadian production of cAMP and as a result lengthens circadian period of behavioural rhythm. The temporally precise regulation of the cAMP signal by clock-controlled RGS16 is needed for the dorsomedial SCN to maintain a normal phase-relationship to the ventrolateral SCN. Thus, RGS16-dependent temporal regulation of intracellular G protein signalling coordinates the intercellular synchrony of SCN pacemaker neurons and thereby defines the 24 h rhythm in behaviour.", "title": "Circadian regulation of intracellular G-protein signalling mediates intercellular synchrony and rhythmicity in the suprachiasmatic nucleus" }, { "docid": "19979816", "text": "The circadian clock and the cell cycle are major cellular systems that organize global physiology in temporal fashion. It seems conceivable that the potentially conflicting programs are coordinated. We show here that overexpression of MYC in U2OS cells attenuates the clock and conversely promotes cell proliferation while downregulation of MYC strengthens the clock and reduces proliferation. Inhibition of the circadian clock is crucially dependent on the formation of repressive complexes of MYC with MIZ1 and subsequent downregulation of the core clock genes BMAL1 (ARNTL), CLOCK and NPAS2. We show furthermore that BMAL1 expression levels correlate inversely with MYC levels in 102 human lymphomas. Our data suggest that MYC acts as a master coordinator that inversely modulates the impact of cell cycle and circadian clock on gene expression.", "title": "MYC/MIZ1-dependent gene repression inversely coordinates the circadian clock with cell cycle and proliferation" }, { "docid": "4320111", "text": "The expression of clock genes in vertebrates is widespread and not restricted to classical clock structures. The expression of the Clock gene in zebrafish shows a strong circadian oscillation in many tissues in vivo and in culture, showing that endogenous oscillators exist in peripheral organs. A defining feature of circadian clocks is that they can be set or entrained to local time, usually by the environmental light-dark cycle. An important question is whether peripheral oscillators are entrained to local time by signals from central pacemakers such as the eyes or are themselves directly light-responsive. Here we show that the peripheral organ clocks of zebrafish are set by light-dark cycles in culture. We also show that a zebrafish-derived cell line contains a circadian oscillator, which is also directly light entrained.", "title": "Light acts directly on organs and cells in culture to set the vertebrate circadian clock." }, { "docid": "27247460", "text": "Many physiological, biochemical and behavioral processes operate under the circadian rhythm, which is generated by an internal time-keeping mechanism commonly referred to as the biological clock, in almost all organisms from bacteria to mammals. The core circadian oscillator is composed of an autoregulatory transcription-translation feedback loop, in which CLOCK and BMAL1 are positive regulators. A cell has two mechanisms, \"cell cycle\" and \"cell rhythm\", the relationship between which remains controversial. Therefore, the aim of this study was to explore the effect of Clock and Bmal1 on cell cycle, especially on the G1 phase, using vectors with the tetracycline operator-repressor system. The present study revealed that simultaneous induction of Bmal1 and Clock had an influential effect on the cell cycle in SW480/T-REx/Clock/Bmal1 cells, in which both Clock and Bmal1 could be induced by tetracycline. The observation that induction of both Clock and Bmal1 inhibited cell growth and the significant increase of the G1 phase proportion of in SW480/T-REx/Clock/Bmal1 cells indicated that entry from the G1 to S phase was inhibited by the induction of Clock and Bmal1. Furthermore, overexpression of Clock and Bmal1 prevented the cells from entering into the G2/M phase induced by Paclitaxel, and made the cells more resistant to the agent. In conclusion, we found that overexpression of both Clock and Bmal1 suppressed cell growth. In addition, the present study raised the possibility that Clock and Bmal1 may in part play a role in preventing the cells from entering G1 to S phase of cell cycle via suppression of CyclinD1 expression, and thus acquiring resistance to Paclitaxel.", "title": "OVEREXPRESSION OF BOTH CLOCK AND BMAL1 INHIBITS ENTRY TO S PHASE IN HUMAN COLON CANCER CELLS." }, { "docid": "4385779", "text": "Circadian (∼24 hour) clocks are fundamentally important for coordinated physiology in organisms as diverse as cyanobacteria and humans. All current models of the molecular circadian clockwork in eukaryotic cells are based on transcription-translation feedback loops. Non-transcriptional mechanisms in the clockwork have been difficult to study in mammalian systems. We circumvented these problems by developing novel assays using human red blood cells, which have no nucleus (or DNA) and therefore cannot perform transcription. Our results show that transcription is not required for circadian oscillations in humans, and that non-transcriptional events seem to be sufficient to sustain cellular circadian rhythms. Using red blood cells, we found that peroxiredoxins, highly conserved antioxidant proteins, undergo ∼24-hour redox cycles, which persist for many days under constant conditions (that is, in the absence of external cues). Moreover, these rhythms are entrainable (that is, tunable by environmental stimuli) and temperature-compensated, both key features of circadian rhythms. We anticipate that our findings will facilitate more sophisticated cellular clock models, highlighting the interdependency of transcriptional and non-transcriptional oscillations in potentially all eukaryotic cells.", "title": "Circadian Clocks in Human Red Blood Cells" }, { "docid": "8087082", "text": "The microtubule (MT) cytoskeleton is required for many aspects of cell function, including the transport of intracellular materials, the maintenance of cell polarity, and the regulation of mitosis. These functions are coordinated by MT-associated proteins (MAPs), which work in concert with each other, binding MTs and altering their properties. We have used a MT cosedimentation assay, combined with 1D and 2D PAGE and mass spectrometry, to identify over 250 MAPs from early Drosophila embryos. We have taken two complementary approaches to analyse the cellular function of novel MAPs isolated using this approach. First, we have carried out an RNA interference (RNAi) screen, identifying 21 previously uncharacterised genes involved in MT organisation. Second, we have undertaken a bioinformatics analysis based on binary protein interaction data to produce putative interaction networks of MAPs. By combining both approaches, we have identified and validated MAP complexes with potentially important roles in cell cycle regulation and mitosis. This study therefore demonstrates that biologically relevant data can be harvested using such a multidisciplinary approach, and identifies new MAPs, many of which appear to be important in cell division.", "title": "A Microtubule Interactome: Complexes with Roles in Cell Cycle and Mitosis" }, { "docid": "4587978", "text": "Patterns of daily human activity are controlled by an intrinsic circadian clock that promotes ∼24 hr rhythms in many behavioral and physiological processes. This system is altered in delayed sleep phase disorder (DSPD), a common form of insomnia in which sleep episodes are shifted to later times misaligned with the societal norm. Here, we report a hereditary form of DSPD associated with a dominant coding variation in the core circadian clock gene CRY1, which creates a transcriptional inhibitor with enhanced affinity for circadian activator proteins Clock and Bmal1. This gain-of-function CRY1 variant causes reduced expression of key transcriptional targets and lengthens the period of circadian molecular rhythms, providing a mechanistic link to DSPD symptoms. The allele has a frequency of up to 0.6%, and reverse phenotyping of unrelated families corroborates late and/or fragmented sleep patterns in carriers, suggesting that it affects sleep behavior in a sizeable portion of the human population.", "title": "Mutation of the Human Circadian Clock Gene CRY1 in Familial Delayed Sleep Phase Disorder" }, { "docid": "10704438", "text": "Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance of affected cells that are beyond repair through apoptosis or senescence. The DDR can be activated in response to DNA damage throughout the cell cycle, although the extent of DDR signaling is different in each cell cycle phase. Especially in response to DNA double strand breaks, only a very marginal response was observed during mitosis. Early on it was recognized that cells which are irradiated during mitosis continued division without repairing broken chromosomes. Although these initial observations indicated diminished DNA repair and lack of an acute DNA damage-induced cell cycle arrest, insight into the mechanistic re-wiring of DDR signaling during mitosis was only recently provided. Different mechanisms appear to be at play to inactivate specific signaling axes of the DDR network in mitosis. Importantly, mitotic cells not simply inactivate the entire DDR, but appear to mark their DNA damage for repair after mitotic exit. Since the treatment of cancer frequently involves agents that induce DNA damage as well as agents that block mitotic progression, it is clinically relevant to obtain a better understanding of how cancer cells deal with DNA damage during interphase versus mitosis. In this review, the molecular details concerning DDR signaling during mitosis as well as the consequences of encountering DNA damage during mitosis for cellular fate are discussed.", "title": "The DNA damage response during mitosis." }, { "docid": "16280642", "text": "Podosomes (also termed invadopodia in cancer cells) are actin-rich adhesion structures with matrix degradation activity that develop in various cell types. Despite their significant physiological importance, the molecular mechanism of podosome formation is largely unknown. In this study, we investigated the molecular mechanisms of podosome formation. The expression of various phosphoinositide-binding domains revealed that the podosomes in Src-transformed NIH3T3 (NIH-src) cells are enriched with PtdIns(3,4)P2, suggesting an important role of this phosphoinositide in podosome formation. Live-cell imaging analysis revealed that Src-expression stimulated podosome formation at focal adhesions of NIH3T3 cells after PtdIns(3,4)P2 accumulation. The adaptor protein Tks5/FISH, which is essential for podosome formation, was found to form a complex with Grb2 at adhesion sites in an Src-dependent manner. Further, it was found that N-WASP bound all SH3 domains of Tks5/FISH, which facilitated circular podosome formation. These results indicate that augmentation of the N-WASP-Arp2/3 signal was accomplished on the platform of Tks5/FISH-Grb2 complex at focal adhesions, which is stabilized by PtdIns(3,4)P2.", "title": "Sequential signals toward podosome formation in NIH-src cells" }, { "docid": "7622767", "text": "We have used microinjection and time-lapse video microscopy to study the role of cyclin A in mitosis. We have injected purified, active cyclin A/cyclin-dependent kinase 2 (CDK2) into synchronized cells at specific points in the cell cycle and assayed its effect on cell division. We find that cyclin A/CDK2 will drive G2 phase cells into mitosis within 30 min of microinjection, up to 4 h before control cells enter mitosis. Often this premature mitosis is abnormal; the chromosomes do not completely condense and daughter cells fuse. Remarkably, microinjecting cyclin A/CDK2 into S phase cells has no effect on progress through the following G2 phase or mitosis. In complementary experiments we have microinjected the amino terminus of p21Cip1/Waf1/Sdi1 (p21N) into cells to inhibit cyclin A/CDK2 activity. We find that p21N will prevent S phase or G2 phase cells from entering mitosis, and will cause early prophase cells to return to interphase. These results suggest that cyclin A/CDK2 is a rate-limiting component required for entry into mitosis, and for progress through mitosis until late prophase. They also suggest that cyclin A/CDK2 may be the target of the recently described prophase checkpoint.", "title": "Human Cyclin a Is Required for Mitosis until Mid Prophase" }, { "docid": "16398049", "text": "Genomes are arranged non-randomly in the 3D space of the cell nucleus. Here, we have developed HIPMap, a high-precision, high-throughput, automated fluorescent in situ hybridization imaging pipeline, for mapping of the spatial location of genome regions at large scale. High-throughput imaging position mapping (HIPMap) enabled an unbiased siRNA screen for factors involved in genome organization in human cells. We identify 50 cellular factors required for proper positioning of a set of functionally diverse genomic loci. Positioning factors include chromatin remodelers, histone modifiers, and nuclear envelope and pore proteins. Components of the replication and post-replication chromatin re-assembly machinery are prominently represented among positioning factors, and timely progression of cells through replication, but not mitosis, is required for correct gene positioning. Our results establish a method for the large-scale mapping of genome locations and have led to the identification of a compendium of cellular factors involved in spatial genome organization.", "title": "Identification of Gene Positioning Factors Using High-Throughput Imaging Mapping" }, { "docid": "8816869", "text": "Circadian timing is generated through a unique series of autoregulatory interactions termed the molecular clock. Behavioral rhythms subject to the molecular clock are well characterized. We demonstrate a role for Bmal1 and Clock in the regulation of glucose homeostasis. Inactivation of the known clock components Bmal1 (Mop3) and Clock suppress the diurnal variation in glucose and triglycerides. Gluconeogenesis is abolished by deletion of Bmal1 and is depressed in Clock mutants, but the counterregulatory response of corticosterone and glucagon to insulin-induced hypoglycaemia is retained. Furthermore, a high-fat diet modulates carbohydrate metabolism by amplifying circadian variation in glucose tolerance and insulin sensitivity, and mutation of Clock restores the chow-fed phenotype. Bmal1 and Clock, genes that function in the core molecular clock, exert profound control over recovery from insulin-induced hypoglycaemia. Furthermore, asynchronous dietary cues may modify glucose homeostasis via their interactions with peripheral molecular clocks.", "title": "BMAL1 and CLOCK, Two Essential Components of the Circadian Clock, Are Involved in Glucose Homeostasis" }, { "docid": "15473205", "text": "The African trypanosome, Trypanosoma brucei, maintains an integral link between cell cycle regulation and differentiation during its intricate life cycle. Whilst extensive changes in phosphorylation have been documented between the mammalian bloodstream form and the insect procyclic form, relatively little is known about the parasite's protein kinases (PKs) involved in the control of cellular proliferation and differentiation. To address this, a T. brucei kinome-wide RNAi cell line library was generated, allowing independent inducible knockdown of each of the parasite's 190 predicted protein kinases. Screening of this library using a cell viability assay identified ≥42 PKs that are required for normal bloodstream form proliferation in culture. A secondary screen identified 24 PKs whose RNAi-mediated depletion resulted in a variety of cell cycle defects including in G1/S, kinetoplast replication/segregation, mitosis and cytokinesis, 15 of which are novel cell cycle regulators. A further screen identified for the first time two PKs, named repressor of differentiation kinase (RDK1 and RDK2), depletion of which promoted bloodstream to procyclic form differentiation. RDK1 is a membrane-associated STE11-like PK, whilst RDK2 is a NEK PK that is essential for parasite proliferation. RDK1 acts in conjunction with the PTP1/PIP39 phosphatase cascade to block uncontrolled bloodstream to procyclic form differentiation, whilst RDK2 is a PK whose depletion efficiently induces differentiation in the absence of known triggers. Thus, the RNAi kinome library provides a valuable asset for functional analysis of cell signalling pathways in African trypanosomes as well as drug target identification and validation.", "title": "Regulators of Trypanosoma brucei Cell Cycle Progression and Differentiation Identified Using a Kinome-Wide RNAi Screen" }, { "docid": "13618987", "text": "Gene sequences sampled at different points in time can be used to infer molecular phylogenies on a natural timescale of months or years, provided that the sequences in question undergo measurable amounts of evolutionary change between sampling times. Data sets with this property are termed heterochronous and have become increasingly common in several fields of biology, most notably the molecular epidemiology of rapidly evolving viruses. Here we introduce the cross-platform software tool, TempEst (formerly known as Path-O-Gen), for the visualization and analysis of temporally sampled sequence data. Given a molecular phylogeny and the dates of sampling for each sequence, TempEst uses an interactive regression approach to explore the association between genetic divergence through time and sampling dates. TempEst can be used to (1) assess whether there is sufficient temporal signal in the data to proceed with phylogenetic molecular clock analysis, and (2) identify sequences whose genetic divergence and sampling date are incongruent. Examination of the latter can help identify data quality problems, including errors in data annotation, sample contamination, sequence recombination, or alignment error. We recommend that all users of the molecular clock models implemented in BEAST first check their data using TempEst prior to analysis.", "title": "Exploring the temporal structure of heterochronous sequences using TempEst (formerly Path-O-Gen)" }, { "docid": "3052213", "text": "The growing epidemic of obesity and metabolic diseases calls for a better understanding of adipocyte biology. The regulation of transcription in adipocytes is particularly important, as it is a target for several therapeutic approaches. Transcriptional outcomes are influenced by both histone modifications and transcription factor binding. Although the epigenetic states and binding sites of several important transcription factors have been profiled in the mouse 3T3-L1 cell line, such data are lacking in human adipocytes. In this study, we identified H3K56 acetylation sites in human adipocytes derived from mesenchymal stem cells. H3K56 is acetylated by CBP and p300, and deacetylated by SIRT1, all are proteins with important roles in diabetes and insulin signaling. We found that while almost half of the genome shows signs of H3K56 acetylation, the highest level of H3K56 acetylation is associated with transcription factors and proteins in the adipokine signaling and Type II Diabetes pathways. In order to discover the transcription factors that recruit acetyltransferases and deacetylases to sites of H3K56 acetylation, we analyzed DNA sequences near H3K56 acetylated regions and found that the E2F recognition sequence was enriched. Using chromatin immunoprecipitation followed by high-throughput sequencing, we confirmed that genes bound by E2F4, as well as those by HSF-1 and C/EBPα, have higher than expected levels of H3K56 acetylation, and that the transcription factor binding sites and acetylation sites are often adjacent but rarely overlap. We also discovered a significant difference between bound targets of C/EBPα in 3T3-L1 and human adipocytes, highlighting the need to construct species-specific epigenetic and transcription factor binding site maps. This is the first genome-wide profile of H3K56 acetylation, E2F4, C/EBPα and HSF-1 binding in human adipocytes, and will serve as an important resource for better understanding adipocyte transcriptional regulation.", "title": "Genome-Wide Profiling of H3K56 Acetylation and Transcription Factor Binding Sites in Human Adipocytes" }, { "docid": "28195565", "text": "Soluble factors from serum such as lysophosphatidic acid (LPA) are thought to activate the small GTP-binding protein Rho based on their ability to induce actin stress fibers and focal adhesions in a Rho-dependent manner. Cell adhesion to extracellular matrices (ECM) has also been proposed to activate Rho, but this point has been controversial due to the difficulty of distinguishing changes in Rho activity from the structural contributions of ECM to the formation of focal adhesions. To address these questions, we established an assay for GTP-bound cellular Rho. Plating Swiss 3T3 cells on fibronectin-coated dishes elicited a transient inhibition of Rho, followed by a phase of Rho activation. The activation phase was greatly enhanced by serum. In serum-starved adherent cells, LPA induced transient Rho activation, whereas in suspended cells Rho activation was sustained. Furthermore, suspended cells showed higher Rho activity than adherent cells in the presence of serum. These data indicate the existence of an adhesion-dependent negative-feedback loop. We also observed that both cytochalasin D and colchicine trigger Rho activation despite their opposite effects on stress fibers and focal adhesions. Our results show that ECM, cytoskeletal structures and soluble factors all contribute to regulation of Rho activity.", "title": "Regulation of the small GTP-binding protein Rho by cell adhesion and the cytoskeleton." }, { "docid": "7114092", "text": "Megakaryocyte (MK) is the naturally polyploid cell that gives rise to platelets. Polyploidization occurs by endomitosis, which was a process considered to be an incomplete mitosis aborted in anaphase. Here, we used time-lapse confocal video microscopy to visualize the endomitotic process of primary human megakaryocytes. Our results show that the switch from mitosis to endomitosis corresponds to a late failure of cytokinesis accompanied by a backward movement of the 2 daughter cells. No abnormality was observed in the central spindle of endomitotic MKs. A furrow formation was present, but the contractile ring was abnormal because accumulation of nonmuscle myosin IIA was lacking. In addition, a defect in cell elongation was observed in dipolar endomitotic MKs during telophase. RhoA and F-actin were partially concentrated at the site of furrowing. Inhibition of the Rho/Rock pathway caused the disappearance of F-actin at midzone and increased MK ploidy level. This inhibition was associated with a more pronounced defect in furrow formation as well as in spindle elongation. Our results suggest that the late failure of cytokinesis responsible for the endomitotic process is related to a partial defect in the Rho/Rock pathway activation.", "title": "From bloodjournal.hematologylibrary.org at PENN STATE UNIVERSITY on February 23, 2013. For personal use only." }, { "docid": "17124832", "text": "CONTEXT Previous studies indicate that the population attributable risk (PAR) of bladder cancer for tobacco smoking is 50% to 65% in men and 20% to 30% in women and that current cigarette smoking triples bladder cancer risk relative to never smoking. During the last 30 years, incidence rates have remained stable in the United States in men (123.8 per 100,000 person-years to 142.2 per 100,000 person-years) and women (32.5 per 100,000 person-years to 33.2 per 100,000 person-years); however, changing smoking prevalence and cigarette composition warrant revisiting risk estimates for smoking and bladder cancer. \n OBJECTIVE To evaluate the association between tobacco smoking and bladder cancer. \n DESIGN, SETTING, AND PARTICIPANTS Men (n = 281,394) and women (n = 186,134) of the National Institutes of Health-AARP (NIH-AARP) Diet and Health Study cohort completed a lifestyle questionnaire and were followed up between October 25, 1995, and December 31, 2006. Previous prospective cohort studies of smoking and incident bladder cancer were identified by systematic review and relative risks were estimated from fixed-effects models with heterogeneity assessed by the I(2) statistic. \n MAIN OUTCOME MEASURES Hazard ratios (HRs), PARs, and number needed to harm (NNH). \n RESULTS During 4,518,941 person-years of follow-up, incident bladder cancer occurred in 3896 men (144.0 per 100,000 person-years) and 627 women (34.5 per 100,000 person-years). Former smokers (119.8 per 100,000 person-years; HR, 2.22; 95% confidence interval [CI], 2.03-2.44; NNH, 1250) and current smokers (177.3 per 100,000 person-years; HR, 4.06; 95% CI, 3.66-4.50; NNH, 727) had higher risks of bladder cancer than never smokers (39.8 per 100,000 person-years). In contrast, the summary risk estimate for current smoking in 7 previous studies (initiated between 1963 and 1987) was 2.94 (95% CI, 2.45-3.54; I(2) = 0.0%). The PAR for ever smoking in our study was 0.50 (95% CI, 0.45-0.54) in men and 0.52 (95% CI, 0.45-0.59) in women. \n CONCLUSION Compared with a pooled estimate of US data from cohorts initiated between 1963 and 1987, relative risks for smoking in the more recent NIH-AARP Diet and Health Study cohort were higher, with PARs for women comparable with those for men.", "title": "Association between smoking and risk of bladder cancer among men and women." } ]

[ { "docid": "2212067", "text": "Circadian cycles and cell cycles are two fundamental periodic processes with a period in the range of 1 day. Consequently, coupling between such cycles can lead to synchronization. Here, we estimated the mutual interactions between the two oscillators by time-lapse imaging of single mammalian NIH3T3 fibroblasts during several days. The analysis of thousands of circadian cycles in dividing cells clearly indicated that both oscillators tick in a 1:1 mode-locked state, with cell divisions occurring tightly 5 h before the peak in circadian Rev-Erbα-YFP reporter expression. In principle, such synchrony may be caused by either unidirectional or bidirectional coupling. While gating of cell division by the circadian cycle has been most studied, our data combined with stochastic modeling unambiguously show that the reverse coupling is predominant in NIH3T3 cells. Moreover, temperature, genetic, and pharmacological perturbations showed that the two interacting cellular oscillators adopt a synchronized state that is highly robust over a wide range of parameters. These findings have implications for circadian function in proliferative tissues, including epidermis, immune cells, and cancer.", "title": "Robust synchronization of coupled circadian and cell cycle oscillators in single mammalian cells" }, { "docid": "10608822", "text": "Daily synchronous rhythms of cell division at the tissue or organism level are observed in many species and suggest that the circadian clock and cell cycle oscillators are coupled. For mammals, despite known mechanistic interactions, the effect of such coupling on clock and cell cycle progression, and hence its biological relevance, is not understood. In particular, we do not know how the temporal organization of cell division at the single-cell level produces this daily rhythm at the tissue level. Here we use multispectral imaging of single live cells, computational methods, and mathematical modeling to address this question in proliferating mouse fibroblasts. We show that in unsynchronized cells the cell cycle and circadian clock robustly phase lock each other in a 1:1 fashion so that in an expanding cell population the two oscillators oscillate in a synchronized way with a common frequency. Dexamethasone-induced synchronization reveals additional clock states. As well as the low-period phase-locked state there are distinct coexisting states with a significantly higher period clock. Cells transition to these states after dexamethasone synchronization. The temporal coordination of cell division by phase locking to the clock at a single-cell level has significant implications because disordered circadian function is increasingly being linked to the pathogenesis of many diseases, including cancer.", "title": "Phase locking and multiple oscillating attractors for the coupled mammalian clock and cell cycle." } ]

[ { "docid": "11557602", "text": "LXR alpha is a nuclear receptor that has previously been shown to regulate the metabolic conversion of cholesterol to bile acids. Here we define a role for this transcription factor in the control of cellular cholesterol efflux. We demonstrate that retroviral expression of LXR alpha in NIH 3T3 fibroblasts or RAW264.7 macrophages and/or treatment of these cells with oxysterol ligands of LXR results in 7- to 30-fold induction of the mRNA encoding the putative cholesterol/phospholipid transporter ATP-binding cassette (ABC)A1. In contrast, induction of ABCA1 mRNA in response to oxysterols is attenuated in cells that constitutively express dominant-negative forms of LXR alpha or LXR beta that lack the AF2 transcriptional activation domain. We further demonstrate that expression of LXR alpha in NIH 3T3 fibroblasts and/or treatment of these cells with oxysterols is sufficient to stimulate cholesterol efflux to extracellular apolipoprotein AI. The ability of oxysterol ligands of LXR to stimulate efflux is dramatically reduced in Tangier fibroblasts, which carry a loss of function mutation in the ABCA1 gene. Taken together, these results indicate that cellular cholesterol efflux is controlled, at least in part, at the level of transcription by a nuclear receptor-signaling pathway. They suggest a model in which activation of LXRs by oxysterols in response to cellular sterol loading leads to induction of the ABCA1 transporter and the stimulation of lipid efflux to extracellular acceptors. These findings have important implications for our understanding of mammalian cholesterol homeostasis and suggest new opportunities for pharmacological regulation of cellular lipid metabolism.", "title": "Control of cellular cholesterol efflux by the nuclear oxysterol receptor LXR alpha." }, { "docid": "14471161", "text": "Circadian disruption accelerates cancer progression, whereas circadian reinforcement could halt it. Mice with P03 pancreatic adenocarcinoma (n = 77) were synchronized and fed ad libitum (AL) or with meal timing (MT) from Zeitgeber time (ZT) 2 to ZT6 with normal or fat diet. Tumor gene expression profiling was determined with DNA microarrays at endogenous circadian time (CT) 4 and CT16. Circadian mRNA expression patterns were determined for clock genes Rev-erbalpha, Per2, and Bmal1, cellular stress genes Hspa8 and Cirbp, and cyclin A2 gene Ccna2 in liver and tumor. The 24-hour patterns in telemetered rest-activity and body temperature and plasma corticosterone and insulin-like growth factor-I (IGF-I) were assessed. We showed that MT inhibited cancer growth by approximately 40% as compared with AL (P = 0.011) irrespective of calorie intake. Clock gene transcription remained arrhythmic in tumors irrespective of feeding schedule or diet. Yet, MT upregulated or downregulated the expression of 423 tumor genes, according to CT. Moreover, 36 genes involved in cellular stress, cell cycle, and metabolism were upregulated at one CT and downregulated 12 h apart. MT induced >10-fold circadian expression of Hspa8, Cirbp, and Ccna2 in tumors. Corticosterone or IGF-I patterns played no role in tumor growth inhibition. In contrast, MT consistently doubled the circadian amplitude of body temperature. Peak and trough respectively corresponded to peak expressions of Hspa8 and Cirbp in tumors. The reinforcement of the host circadian timing system with MT induced 24-hour rhythmic expression of critical genes in clock-deficient tumors, which translated into cancer growth inhibition. Targeting circadian clocks represents a novel potential challenge for cancer therapeutics.", "title": "Cancer inhibition through circadian reprogramming of tumor transcriptome with meal timing." }, { "docid": "11565780", "text": "Synchronous oscillations of thousands of cellular clocks in the suprachiasmatic nucleus (SCN), the circadian centre, are coordinated by precisely timed cell-cell communication, the principle of which is largely unknown. Here we show that the amount of RGS16 (regulator of G protein signalling 16), a protein known to inactivate Gαi, increases at a selective circadian time to allow time-dependent activation of intracellular cyclic AMP signalling in the SCN. Gene ablation of Rgs16 leads to the loss of circadian production of cAMP and as a result lengthens circadian period of behavioural rhythm. The temporally precise regulation of the cAMP signal by clock-controlled RGS16 is needed for the dorsomedial SCN to maintain a normal phase-relationship to the ventrolateral SCN. Thus, RGS16-dependent temporal regulation of intracellular G protein signalling coordinates the intercellular synchrony of SCN pacemaker neurons and thereby defines the 24 h rhythm in behaviour.", "title": "Circadian regulation of intracellular G-protein signalling mediates intercellular synchrony and rhythmicity in the suprachiasmatic nucleus" }, { "docid": "19979816", "text": "The circadian clock and the cell cycle are major cellular systems that organize global physiology in temporal fashion. It seems conceivable that the potentially conflicting programs are coordinated. We show here that overexpression of MYC in U2OS cells attenuates the clock and conversely promotes cell proliferation while downregulation of MYC strengthens the clock and reduces proliferation. Inhibition of the circadian clock is crucially dependent on the formation of repressive complexes of MYC with MIZ1 and subsequent downregulation of the core clock genes BMAL1 (ARNTL), CLOCK and NPAS2. We show furthermore that BMAL1 expression levels correlate inversely with MYC levels in 102 human lymphomas. Our data suggest that MYC acts as a master coordinator that inversely modulates the impact of cell cycle and circadian clock on gene expression.", "title": "MYC/MIZ1-dependent gene repression inversely coordinates the circadian clock with cell cycle and proliferation" }, { "docid": "15473205", "text": "The African trypanosome, Trypanosoma brucei, maintains an integral link between cell cycle regulation and differentiation during its intricate life cycle. Whilst extensive changes in phosphorylation have been documented between the mammalian bloodstream form and the insect procyclic form, relatively little is known about the parasite's protein kinases (PKs) involved in the control of cellular proliferation and differentiation. To address this, a T. brucei kinome-wide RNAi cell line library was generated, allowing independent inducible knockdown of each of the parasite's 190 predicted protein kinases. Screening of this library using a cell viability assay identified ≥42 PKs that are required for normal bloodstream form proliferation in culture. A secondary screen identified 24 PKs whose RNAi-mediated depletion resulted in a variety of cell cycle defects including in G1/S, kinetoplast replication/segregation, mitosis and cytokinesis, 15 of which are novel cell cycle regulators. A further screen identified for the first time two PKs, named repressor of differentiation kinase (RDK1 and RDK2), depletion of which promoted bloodstream to procyclic form differentiation. RDK1 is a membrane-associated STE11-like PK, whilst RDK2 is a NEK PK that is essential for parasite proliferation. RDK1 acts in conjunction with the PTP1/PIP39 phosphatase cascade to block uncontrolled bloodstream to procyclic form differentiation, whilst RDK2 is a PK whose depletion efficiently induces differentiation in the absence of known triggers. Thus, the RNAi kinome library provides a valuable asset for functional analysis of cell signalling pathways in African trypanosomes as well as drug target identification and validation.", "title": "Regulators of Trypanosoma brucei Cell Cycle Progression and Differentiation Identified Using a Kinome-Wide RNAi Screen" }, { "docid": "4320111", "text": "The expression of clock genes in vertebrates is widespread and not restricted to classical clock structures. The expression of the Clock gene in zebrafish shows a strong circadian oscillation in many tissues in vivo and in culture, showing that endogenous oscillators exist in peripheral organs. A defining feature of circadian clocks is that they can be set or entrained to local time, usually by the environmental light-dark cycle. An important question is whether peripheral oscillators are entrained to local time by signals from central pacemakers such as the eyes or are themselves directly light-responsive. Here we show that the peripheral organ clocks of zebrafish are set by light-dark cycles in culture. We also show that a zebrafish-derived cell line contains a circadian oscillator, which is also directly light entrained.", "title": "Light acts directly on organs and cells in culture to set the vertebrate circadian clock." }, { "docid": "27247460", "text": "Many physiological, biochemical and behavioral processes operate under the circadian rhythm, which is generated by an internal time-keeping mechanism commonly referred to as the biological clock, in almost all organisms from bacteria to mammals. The core circadian oscillator is composed of an autoregulatory transcription-translation feedback loop, in which CLOCK and BMAL1 are positive regulators. A cell has two mechanisms, \"cell cycle\" and \"cell rhythm\", the relationship between which remains controversial. Therefore, the aim of this study was to explore the effect of Clock and Bmal1 on cell cycle, especially on the G1 phase, using vectors with the tetracycline operator-repressor system. The present study revealed that simultaneous induction of Bmal1 and Clock had an influential effect on the cell cycle in SW480/T-REx/Clock/Bmal1 cells, in which both Clock and Bmal1 could be induced by tetracycline. The observation that induction of both Clock and Bmal1 inhibited cell growth and the significant increase of the G1 phase proportion of in SW480/T-REx/Clock/Bmal1 cells indicated that entry from the G1 to S phase was inhibited by the induction of Clock and Bmal1. Furthermore, overexpression of Clock and Bmal1 prevented the cells from entering into the G2/M phase induced by Paclitaxel, and made the cells more resistant to the agent. In conclusion, we found that overexpression of both Clock and Bmal1 suppressed cell growth. In addition, the present study raised the possibility that Clock and Bmal1 may in part play a role in preventing the cells from entering G1 to S phase of cell cycle via suppression of CyclinD1 expression, and thus acquiring resistance to Paclitaxel.", "title": "OVEREXPRESSION OF BOTH CLOCK AND BMAL1 INHIBITS ENTRY TO S PHASE IN HUMAN COLON CANCER CELLS." }, { "docid": "3805841", "text": "The MYC oncogene encodes MYC, a transcription factor that binds the genome through sites termed E-boxes (5'-CACGTG-3'), which are identical to the binding sites of the heterodimeric CLOCK-BMAL1 master circadian transcription factor. Hence, we hypothesized that ectopic MYC expression perturbs the clock by deregulating E-box-driven components of the circadian network in cancer cells. We report here that deregulated expression of MYC or N-MYC disrupts the molecular clock in vitro by directly inducing REV-ERBα to dampen expression and oscillation of BMAL1, and this could be rescued by knockdown of REV-ERB. REV-ERBα expression predicts poor clinical outcome for N-MYC-driven human neuroblastomas that have diminished BMAL1 expression, and re-expression of ectopic BMAL1 in neuroblastoma cell lines suppresses their clonogenicity. Further, ectopic MYC profoundly alters oscillation of glucose metabolism and perturbs glutaminolysis. Our results demonstrate an unsuspected link between oncogenic transformation and circadian and metabolic dysrhythmia, which we surmise to be advantageous for cancer.", "title": "MYC Disrupts the Circadian Clock and Metabolism in Cancer Cells." }, { "docid": "4385779", "text": "Circadian (∼24 hour) clocks are fundamentally important for coordinated physiology in organisms as diverse as cyanobacteria and humans. All current models of the molecular circadian clockwork in eukaryotic cells are based on transcription-translation feedback loops. Non-transcriptional mechanisms in the clockwork have been difficult to study in mammalian systems. We circumvented these problems by developing novel assays using human red blood cells, which have no nucleus (or DNA) and therefore cannot perform transcription. Our results show that transcription is not required for circadian oscillations in humans, and that non-transcriptional events seem to be sufficient to sustain cellular circadian rhythms. Using red blood cells, we found that peroxiredoxins, highly conserved antioxidant proteins, undergo ∼24-hour redox cycles, which persist for many days under constant conditions (that is, in the absence of external cues). Moreover, these rhythms are entrainable (that is, tunable by environmental stimuli) and temperature-compensated, both key features of circadian rhythms. We anticipate that our findings will facilitate more sophisticated cellular clock models, highlighting the interdependency of transcriptional and non-transcriptional oscillations in potentially all eukaryotic cells.", "title": "Circadian Clocks in Human Red Blood Cells" }, { "docid": "10704438", "text": "Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance of affected cells that are beyond repair through apoptosis or senescence. The DDR can be activated in response to DNA damage throughout the cell cycle, although the extent of DDR signaling is different in each cell cycle phase. Especially in response to DNA double strand breaks, only a very marginal response was observed during mitosis. Early on it was recognized that cells which are irradiated during mitosis continued division without repairing broken chromosomes. Although these initial observations indicated diminished DNA repair and lack of an acute DNA damage-induced cell cycle arrest, insight into the mechanistic re-wiring of DDR signaling during mitosis was only recently provided. Different mechanisms appear to be at play to inactivate specific signaling axes of the DDR network in mitosis. Importantly, mitotic cells not simply inactivate the entire DDR, but appear to mark their DNA damage for repair after mitotic exit. Since the treatment of cancer frequently involves agents that induce DNA damage as well as agents that block mitotic progression, it is clinically relevant to obtain a better understanding of how cancer cells deal with DNA damage during interphase versus mitosis. In this review, the molecular details concerning DDR signaling during mitosis as well as the consequences of encountering DNA damage during mitosis for cellular fate are discussed.", "title": "The DNA damage response during mitosis." }, { "docid": "16280642", "text": "Podosomes (also termed invadopodia in cancer cells) are actin-rich adhesion structures with matrix degradation activity that develop in various cell types. Despite their significant physiological importance, the molecular mechanism of podosome formation is largely unknown. In this study, we investigated the molecular mechanisms of podosome formation. The expression of various phosphoinositide-binding domains revealed that the podosomes in Src-transformed NIH3T3 (NIH-src) cells are enriched with PtdIns(3,4)P2, suggesting an important role of this phosphoinositide in podosome formation. Live-cell imaging analysis revealed that Src-expression stimulated podosome formation at focal adhesions of NIH3T3 cells after PtdIns(3,4)P2 accumulation. The adaptor protein Tks5/FISH, which is essential for podosome formation, was found to form a complex with Grb2 at adhesion sites in an Src-dependent manner. Further, it was found that N-WASP bound all SH3 domains of Tks5/FISH, which facilitated circular podosome formation. These results indicate that augmentation of the N-WASP-Arp2/3 signal was accomplished on the platform of Tks5/FISH-Grb2 complex at focal adhesions, which is stabilized by PtdIns(3,4)P2.", "title": "Sequential signals toward podosome formation in NIH-src cells" }, { "docid": "7808055", "text": "BACKGROUND It is not yet known whether DNA methylation levels can be used to accurately predict age across a broad spectrum of human tissues and cell types, nor whether the resulting age prediction is a biologically meaningful measure. \n RESULTS I developed a multi-tissue predictor of age that allows one to estimate the DNA methylation age of most tissues and cell types. The predictor, which is freely available, was developed using 8,000 samples from 82 Illumina DNA methylation array datasets, encompassing 51 healthy tissues and cell types. I found that DNA methylation age has the following properties: first, it is close to zero for embryonic and induced pluripotent stem cells; second, it correlates with cell passage number; third, it gives rise to a highly heritable measure of age acceleration; and, fourth, it is applicable to chimpanzee tissues. Analysis of 6,000 cancer samples from 32 datasets showed that all of the considered 20 cancer types exhibit significant age acceleration, with an average of 36 years. Low age-acceleration of cancer tissue is associated with a high number of somatic mutations and TP53 mutations, while mutations in steroid receptors greatly accelerate DNA methylation age in breast cancer. Finally, I characterize the 353 CpG sites that together form an aging clock in terms of chromatin states and tissue variance. \n CONCLUSIONS I propose that DNA methylation age measures the cumulative effect of an epigenetic maintenance system. This novel epigenetic clock can be used to address a host of questions in developmental biology, cancer and aging research.", "title": "DNA methylation age of human tissues and cell types" }, { "docid": "7622767", "text": "We have used microinjection and time-lapse video microscopy to study the role of cyclin A in mitosis. We have injected purified, active cyclin A/cyclin-dependent kinase 2 (CDK2) into synchronized cells at specific points in the cell cycle and assayed its effect on cell division. We find that cyclin A/CDK2 will drive G2 phase cells into mitosis within 30 min of microinjection, up to 4 h before control cells enter mitosis. Often this premature mitosis is abnormal; the chromosomes do not completely condense and daughter cells fuse. Remarkably, microinjecting cyclin A/CDK2 into S phase cells has no effect on progress through the following G2 phase or mitosis. In complementary experiments we have microinjected the amino terminus of p21Cip1/Waf1/Sdi1 (p21N) into cells to inhibit cyclin A/CDK2 activity. We find that p21N will prevent S phase or G2 phase cells from entering mitosis, and will cause early prophase cells to return to interphase. These results suggest that cyclin A/CDK2 is a rate-limiting component required for entry into mitosis, and for progress through mitosis until late prophase. They also suggest that cyclin A/CDK2 may be the target of the recently described prophase checkpoint.", "title": "Human Cyclin a Is Required for Mitosis until Mid Prophase" }, { "docid": "16398049", "text": "Genomes are arranged non-randomly in the 3D space of the cell nucleus. Here, we have developed HIPMap, a high-precision, high-throughput, automated fluorescent in situ hybridization imaging pipeline, for mapping of the spatial location of genome regions at large scale. High-throughput imaging position mapping (HIPMap) enabled an unbiased siRNA screen for factors involved in genome organization in human cells. We identify 50 cellular factors required for proper positioning of a set of functionally diverse genomic loci. Positioning factors include chromatin remodelers, histone modifiers, and nuclear envelope and pore proteins. Components of the replication and post-replication chromatin re-assembly machinery are prominently represented among positioning factors, and timely progression of cells through replication, but not mitosis, is required for correct gene positioning. Our results establish a method for the large-scale mapping of genome locations and have led to the identification of a compendium of cellular factors involved in spatial genome organization.", "title": "Identification of Gene Positioning Factors Using High-Throughput Imaging Mapping" }, { "docid": "8816869", "text": "Circadian timing is generated through a unique series of autoregulatory interactions termed the molecular clock. Behavioral rhythms subject to the molecular clock are well characterized. We demonstrate a role for Bmal1 and Clock in the regulation of glucose homeostasis. Inactivation of the known clock components Bmal1 (Mop3) and Clock suppress the diurnal variation in glucose and triglycerides. Gluconeogenesis is abolished by deletion of Bmal1 and is depressed in Clock mutants, but the counterregulatory response of corticosterone and glucagon to insulin-induced hypoglycaemia is retained. Furthermore, a high-fat diet modulates carbohydrate metabolism by amplifying circadian variation in glucose tolerance and insulin sensitivity, and mutation of Clock restores the chow-fed phenotype. Bmal1 and Clock, genes that function in the core molecular clock, exert profound control over recovery from insulin-induced hypoglycaemia. Furthermore, asynchronous dietary cues may modify glucose homeostasis via their interactions with peripheral molecular clocks.", "title": "BMAL1 and CLOCK, Two Essential Components of the Circadian Clock, Are Involved in Glucose Homeostasis" }, { "docid": "9291668", "text": "The process of aging results in a host of changes at the cellular and molecular levels, which include senescence, telomere shortening, and changes in gene expression. Epigenetic patterns also change over the lifespan, suggesting that epigenetic changes may constitute an important component of the aging process. The epigenetic mark that has been most highly studied is DNA methylation, the presence of methyl groups at CpG dinucleotides. These dinucleotides are often located near gene promoters and associate with gene expression levels. Early studies indicated that global levels of DNA methylation increase over the first few years of life and then decrease beginning in late adulthood. Recently, with the advent of microarray and next-generation sequencing technologies, increases in variability of DNA methylation with age have been observed, and a number of site-specific patterns have been identified. It has also been shown that certain CpG sites are highly associated with age, to the extent that prediction models using a small number of these sites can accurately predict the chronological age of the donor. Together, these observations point to the existence of two phenomena that both contribute to age-related DNA methylation changes: epigenetic drift and the epigenetic clock. In this review, we focus on healthy human aging throughout the lifetime and discuss the dynamics of DNA methylation as well as how interactions between the genome, environment, and the epigenome influence aging rates. We also discuss the impact of determining 'epigenetic age' for human health and outline some important caveats to existing and future studies.", "title": " DNA methylation and healthy human aging" }, { "docid": "28195565", "text": "Soluble factors from serum such as lysophosphatidic acid (LPA) are thought to activate the small GTP-binding protein Rho based on their ability to induce actin stress fibers and focal adhesions in a Rho-dependent manner. Cell adhesion to extracellular matrices (ECM) has also been proposed to activate Rho, but this point has been controversial due to the difficulty of distinguishing changes in Rho activity from the structural contributions of ECM to the formation of focal adhesions. To address these questions, we established an assay for GTP-bound cellular Rho. Plating Swiss 3T3 cells on fibronectin-coated dishes elicited a transient inhibition of Rho, followed by a phase of Rho activation. The activation phase was greatly enhanced by serum. In serum-starved adherent cells, LPA induced transient Rho activation, whereas in suspended cells Rho activation was sustained. Furthermore, suspended cells showed higher Rho activity than adherent cells in the presence of serum. These data indicate the existence of an adhesion-dependent negative-feedback loop. We also observed that both cytochalasin D and colchicine trigger Rho activation despite their opposite effects on stress fibers and focal adhesions. Our results show that ECM, cytoskeletal structures and soluble factors all contribute to regulation of Rho activity.", "title": "Regulation of the small GTP-binding protein Rho by cell adhesion and the cytoskeleton." }, { "docid": "8087082", "text": "The microtubule (MT) cytoskeleton is required for many aspects of cell function, including the transport of intracellular materials, the maintenance of cell polarity, and the regulation of mitosis. These functions are coordinated by MT-associated proteins (MAPs), which work in concert with each other, binding MTs and altering their properties. We have used a MT cosedimentation assay, combined with 1D and 2D PAGE and mass spectrometry, to identify over 250 MAPs from early Drosophila embryos. We have taken two complementary approaches to analyse the cellular function of novel MAPs isolated using this approach. First, we have carried out an RNA interference (RNAi) screen, identifying 21 previously uncharacterised genes involved in MT organisation. Second, we have undertaken a bioinformatics analysis based on binary protein interaction data to produce putative interaction networks of MAPs. By combining both approaches, we have identified and validated MAP complexes with potentially important roles in cell cycle regulation and mitosis. This study therefore demonstrates that biologically relevant data can be harvested using such a multidisciplinary approach, and identifies new MAPs, many of which appear to be important in cell division.", "title": "A Microtubule Interactome: Complexes with Roles in Cell Cycle and Mitosis" }, { "docid": "4587978", "text": "Patterns of daily human activity are controlled by an intrinsic circadian clock that promotes ∼24 hr rhythms in many behavioral and physiological processes. This system is altered in delayed sleep phase disorder (DSPD), a common form of insomnia in which sleep episodes are shifted to later times misaligned with the societal norm. Here, we report a hereditary form of DSPD associated with a dominant coding variation in the core circadian clock gene CRY1, which creates a transcriptional inhibitor with enhanced affinity for circadian activator proteins Clock and Bmal1. This gain-of-function CRY1 variant causes reduced expression of key transcriptional targets and lengthens the period of circadian molecular rhythms, providing a mechanistic link to DSPD symptoms. The allele has a frequency of up to 0.6%, and reverse phenotyping of unrelated families corroborates late and/or fragmented sleep patterns in carriers, suggesting that it affects sleep behavior in a sizeable portion of the human population.", "title": "Mutation of the Human Circadian Clock Gene CRY1 in Familial Delayed Sleep Phase Disorder" }, { "docid": "335029", "text": "The eukaryotic genome consists of DNA molecules far longer than the cells that contain them. They reach their greatest compaction during chromosome condensation in mitosis. This process is aided by condensin, a structural maintenance of chromosomes (SMC) family member. The spatial organization of mitotic chromosomes and how condensin shapes chromatin architecture are not yet fully understood. Here we use chromosome conformation capture (Hi-C) to study mitotic chromosome condensation in the fission yeast Schizosaccharomyces pombe. This showed that the interphase landscape characterized by small chromatin domains is replaced by fewer but larger domains in mitosis. Condensin achieves this by setting up longer-range, intrachromosomal DNA interactions, which compact and individualize chromosomes. At the same time, local chromatin contacts are constrained by condensin, with profound implications for local chromatin function during mitosis. Our results highlight condensin as a major determinant that changes the chromatin landscape as cells prepare their genomes for cell division.", "title": "Condensin-mediated remodeling of the mitotic chromatin landscape in fission yeast" } ]

[ { "docid": "8148122", "text": "DNA replication in mammals is regulated via the coordinate firing of clusters of replicons that duplicate megabase-sized chromosome segments at specific times during S-phase. Cytogenetic studies show that these \"replicon clusters\" coalesce as subchromosomal units that persist through multiple cell generations, but the molecular boundaries of such units have remained elusive. Moreover, the extent to which changes in replication timing occur during differentiation and their relationship to transcription changes has not been rigorously investigated. We have constructed high-resolution replication-timing profiles in mouse embryonic stem cells (mESCs) before and after differentiation to neural precursor cells. We demonstrate that chromosomes can be segmented into multimegabase domains of coordinate replication, which we call \"replication domains,\" separated by transition regions whose replication kinetics are consistent with large originless segments. The molecular boundaries of replication domains are remarkably well conserved between distantly related ESC lines and induced pluripotent stem cells. Unexpectedly, ESC differentiation was accompanied by the consolidation of smaller differentially replicating domains into larger coordinately replicated units whose replication time was more aligned to isochore GC content and the density of LINE-1 transposable elements, but not gene density. Replication-timing changes were coordinated with transcription changes for weak promoters more than strong promoters, and were accompanied by rearrangements in subnuclear position. We conclude that replication profiles are cell-type specific, and changes in these profiles reveal chromosome segments that undergo large changes in organization during differentiation. Moreover, smaller replication domains and a higher density of timing transition regions that interrupt isochore replication timing define a novel characteristic of the pluripotent state.", "title": "Global Reorganization of Replication Domains During Embryonic Stem Cell Differentiation" } ]

[ { "docid": "27279525", "text": "The present study was undertaken to detect, characterize, and study differentiation potential of stem cells in adult rabbit, sheep, monkey, and menopausal human ovarian surface epithelium (OSE). Two distinct populations of putative stem cells (PSCs) of variable size were detected in scraped OSE, one being smaller and other similar in size to the surrounding red blood cells in the scraped OSE. The smaller 1-3 μm very small embryonic-like PSCs were pluripotent in nature with nuclear Oct-4 and cell surface SSEA-4, whereas the bigger 4-7 μm cells with cytoplasmic localization of Oct-4 and minimal expression of SSEA-4 were possibly the tissue committed progenitor stem cells. Pluripotent gene transcripts of Oct-4, Oct-4A, Nanog, Sox-2, TERT, and Stat-3 in human and sheep OSE were detected by reverse transcriptase-polymerase chain reaction. The PSCs underwent spontaneous differentiation into oocyte-like structures, parthenote-like structures, embryoid body-like structures, cells with neuronal-like phenotype, and embryonic stem cell-like colonies, whereas the epithelial cells transformed into mesenchymal phenotype by epithelial-mesenchymal transition in 3 weeks of OSE culture. Germ cell markers like c-Kit, DAZL, GDF-9, VASA, and ZP4 were immuno-localized in oocyte-like structures. In conclusion, as opposed to the existing view of OSE being a bipotent source of oocytes and granulosa cells, mammalian ovaries harbor distinct very small embryonic-like PSCs and tissue committed progenitor stem cells population that have the potential to develop into oocyte-like structures in vitro, whereas mesenchymal fibroblasts appear to form supporting granulosa-like somatic cells. Research at the single-cell level, including complete gene expression profiling, is required to further confirm whether postnatal oogenesis is a conserved phenomenon in adult mammals.", "title": "Detection, characterization, and spontaneous differentiation in vitro of very small embryonic-like putative stem cells in adult mammalian ovary." }, { "docid": "24766509", "text": "Previously, we have demonstrated that mesenchymal stem cells could be differentiated into steroidogenic cells through steroidogenic factor-1 and 8bromo-cAMP treatment. Use of liver receptor homolog-1, another of the nuclear receptor 5A family nuclear receptors, with 8bromo-cAMP also resulted in the differentiation of human mesenchymal stem cells into steroid hormone-producing cells. The same approaches could not be applied to other undifferentiated cells such as embryonic stem cells or embryonal carcinoma cells, because the over-expression of the nuclear receptor 5A family is cytotoxic to these cells. We established embryonic stem cells carrying tetracycline-regulated steroidogenic factor-1 gene at the ROSA26 locus. The embryonic stem cells were first differentiated into a mesenchymal cell lineage by culturing on collagen IV-coated dishes and treating with pulse exposures of retinoic acid before expression of steroidogenic factor-1. Although the untreated embryonic stem cells could not be converted into steroidogenic cells by expression of steroidogenic factor-1 in the absence of leukemia inhibitory factor due to inability of the cells to survive, the differentiated cells could be successfully converted into steroidogenic cells when expression of steroidogenic factor-1 was induced. They exhibited characteristics of adrenocortical-like cells and produced a large amount of corticosterone. These results indicated that pluripotent stem cells could be differentiated into steroidogenic cells by the nuclear receptor 5A family of protein via the mesenchymal cell lineage. This approach may provide a source of cells for future gene therapy for diseases caused by steroidogenesis deficiencies.", "title": "Differentiation of mesenchymal stem cells and embryonic stem cells into steroidogenic cells using steroidogenic factor-1 and liver receptor homolog-1." }, { "docid": "14225271", "text": "Differentiating somatic cells are progressively restricted to specialized functions during ontogeny, but they can be experimentally directed to form other cell types, including those with complete embryonic potential. Early nuclear reprogramming methods, such as somatic cell nuclear transfer (SCNT) and cell fusion, posed significant technical hurdles to precise dissection of the regulatory programmes governing cell identity. However, the discovery of reprogramming by ectopic expression of a defined set of transcription factors, known as direct reprogramming, provided a tractable platform to uncover molecular characteristics of cellular specification and differentiation, cell type stability and pluripotency. We discuss the control and maintenance of cellular identity during developmental transitions as they have been studied using direct reprogramming, with an emphasis on transcriptional and epigenetic regulation.", "title": "Molecular features of cellular reprogramming and development" }, { "docid": "1744097", "text": "Polycomb group (PcG) proteins form multiprotein complexes, called Polycomb repressive complexes (PRCs). PRC2 contains the PcG proteins EZH2, SUZ12, and EED and represses transcription through methylation of lysine (K) 27 of histone H3 (H3). Suz12 is essential for PRC2 activity and its inactivation results in early lethality of mouse embryos. Here, we demonstrate that Suz12(-/-) mouse embryonic stem (ES) cells can be established and expanded in tissue culture. The Suz12(-/-) ES cells are characterized by global loss of H3K27 trimethylation (H3K27me3) and higher expression levels of differentiation-specific genes. Moreover, Suz12(-/-) ES cells are impaired in proper differentiation, resulting in a lack of repression of ES cell markers as well as activation of differentiation-specific genes. Finally, we demonstrate that the PcGs are actively recruited to several genes during ES cell differentiation, which despite an increase in H3K27me3 levels is not always sufficient to prevent transcriptional activation. In summary, we demonstrate that Suz12 is required for the establishment of specific expression programs required for ES cell differentiation. Furthermore, we provide evidence that PcGs have different mechanisms to regulate transcription during cellular differentiation.", "title": "The polycomb group protein Suz12 is required for embryonic stem cell differentiation." }, { "docid": "3174305", "text": "DNA cytosine methylation is a central epigenetic modification that has essential roles in cellular processes including genome regulation, development and disease. Here we present the first genome-wide, single-base-resolution maps of methylated cytosines in a mammalian genome, from both human embryonic stem cells and fetal fibroblasts, along with comparative analysis of messenger RNA and small RNA components of the transcriptome, several histone modifications, and sites of DNA–protein interaction for several key regulatory factors. Widespread differences were identified in the composition and patterning of cytosine methylation between the two genomes. Nearly one-quarter of all methylation identified in embryonic stem cells was in a non-CG context, suggesting that embryonic stem cells may use different methylation mechanisms to affect gene regulation. Methylation in non-CG contexts showed enrichment in gene bodies and depletion in protein binding sites and enhancers. Non-CG methylation disappeared upon induced differentiation of the embryonic stem cells, and was restored in induced pluripotent stem cells. We identified hundreds of differentially methylated regions proximal to genes involved in pluripotency and differentiation, and widespread reduced methylation levels in fibroblasts associated with lower transcriptional activity. These reference epigenomes provide a foundation for future studies exploring this key epigenetic modification in human disease and development.", "title": "Human DNA methylomes at base resolution show widespread epigenomic differences" }, { "docid": "8759633", "text": "Studies of replication timing provide a handle into previously impenetrable higher-order levels of chromosome organization and their plasticity during development. Although mechanisms regulating replication timing are not clear, novel genome-wide studies provide a thorough survey of the extent to which replication timing is regulated during most of the early cell fate transitions in mammals, revealing coordinated changes of a defined set of 400–800 kb chromosomal segments that involve at least half the genome. Furthermore, changes in replication time are linked to changes in sub-nuclear organization and domain-wide transcriptional potential, and tissue-specific replication timing profiles are conserved from mouse to human, suggesting that the program has developmental significance. Hence, these studies have provided a solid foundation for linking megabase level chromosome structure to function, and suggest a central role for replication in domain-level genome organization.", "title": "Domain-wide regulation of DNA replication timing during mammalian development" }, { "docid": "3874000", "text": "Regenerative medicine is predicated on understanding the mechanisms regulating development and applying these conditions to direct stem cell fate. Embryogenesis is guided by cell-cell and cell-matrix interactions, but it is unclear how these physical cues influence stem cells in culture. We used human embryonic stem cells (hESCs) to examine whether mechanical features of the extracellular microenvironment could differentially modulate mesoderm specification. We found that, on a hydrogel-based compliant matrix, hESCs accumulate β-catenin at cell-cell adhesions and show enhanced Wnt-dependent mesoderm differentiation. Mechanistically, Src-driven ubiquitination of E-cadherin by Cbl-like ubiquitin ligase releases P120-catenin to facilitate transcriptional activity of β-catenin, which initiates and reinforces mesoderm differentiation. By contrast, on a stiff hydrogel matrix, hESCs show elevated integrin-dependent GSK3 and Src activity that promotes β-catenin degradation and inhibits differentiation. Thus, we found that mechanical features of the microenvironmental matrix influence tissue-specific differentiation of hESCs by altering the cellular response to morphogens.", "title": "Tissue Mechanics Orchestrate Wnt-Dependent Human Embryonic Stem Cell Differentiation." }, { "docid": "7492420", "text": "Human embryonic stem cells (hESCs) and induced pluripotent stem cells proliferate rapidly and divide symmetrically producing equivalent progeny cells. In contrast, lineage committed cells acquire an extended symmetrical cell cycle. Self-renewal of tissue-specific stem cells is sustained by asymmetric cell division where one progeny cell remains a progenitor while the partner progeny cell exits the cell cycle and differentiates. There are three principal contexts for considering the operation and regulation of the pluripotent cell cycle: temporal, regulatory, and structural. The primary temporal context that the pluripotent self-renewal cell cycle of hESCs is a short G1 period without reducing periods of time allocated to S phase, G2, and mitosis. The rules that govern proliferation in hESCs remain to be comprehensively established. However, several lines of evidence suggest a key role for the naïve transcriptome of hESCs, which is competent to stringently regulate the embryonic stem cell (ESC) cell cycle. This supports the requirements of pluripotent cells to self-propagate while suppressing expression of genes that confer lineage commitment and/or tissue specificity. However, for the first time, we consider unique dimensions to the architectural organization and assembly of regulatory machinery for gene expression in nuclear microenviornments that define parameters of pluripotency. From both fundamental biological and clinical perspectives, understanding control of the abbreviated ESC cycle can provide options to coordinate control of proliferation versus differentiation. Wound healing, tissue engineering, and cell-based therapy to mitigate developmental aberrations illustrate applications that benefit from knowledge of the biology of the pluripotent cell cycle.", "title": "The abbreviated pluripotent cell cycle." }, { "docid": "9988425", "text": "Pluripotent mouse embryonic stem (ES) cells multiply in simple monoculture by symmetrical divisions. In vivo, however, stem cells are generally thought to depend on specialised cellular microenvironments and to undergo predominantly asymmetric divisions. Ex vivo expansion of pure populations of tissue stem cells has proven elusive. Neural progenitor cells are propagated in combination with differentiating progeny in floating clusters called neurospheres. The proportion of stem cells in neurospheres is low, however, and they cannot be directly observed or interrogated. Here we demonstrate that the complex neurosphere environment is dispensable for stem cell maintenance, and that the combination of fibroblast growth factor 2 (FGF-2) and epidermal growth factor (EGF) is sufficient for derivation and continuous expansion by symmetrical division of pure cultures of neural stem (NS) cells. NS cells were derived first from mouse ES cells. Neural lineage induction was followed by growth factor addition in basal culture media. In the presence of only EGF and FGF-2, resulting NS cells proliferate continuously, are diploid, and clonogenic. After prolonged expansion, they remain able to differentiate efficiently into neurons and astrocytes in vitro and upon transplantation into the adult brain. Colonies generated from single NS cells all produce neurons upon growth factor withdrawal. NS cells uniformly express morphological, cell biological, and molecular features of radial glia, developmental precursors of neurons and glia. Consistent with this profile, adherent NS cell lines can readily be established from foetal mouse brain. Similar NS cells can be generated from human ES cells and human foetal brain. The extrinsic factors EGF plus FGF-2 are sufficient to sustain pure symmetrical self-renewing divisions of NS cells. The resultant cultures constitute the first known example of tissue-specific stem cells that can be propagated without accompanying differentiation. These homogenous cultures will enable delineation of molecular mechanisms that define a tissue-specific stem cell and allow direct comparison with pluripotent ES cells.", "title": "Niche-Independent Symmetrical Self-Renewal of a Mammalian Tissue Stem Cell" }, { "docid": "21271817", "text": "Ectopic expression of the four transcription factors Oct4, Sox2, c-Myc, and Klf4 is sufficient to confer a pluripotent state upon the fibroblast genome, generating induced pluripotent stem (iPS) cells. It remains unknown if nuclear reprogramming induced by these four factors globally resets epigenetic differences between differentiated and pluripotent cells. Here, using novel selection approaches, we have generated iPS cells from fibroblasts to characterize their epigenetic state. Female iPS cells showed reactivation of a somatically silenced X chromosome and underwent random X inactivation upon differentiation. Genome-wide analysis of two key histone modifications indicated that iPS cells are highly similar to ES cells. Consistent with these observations, iPS cells gave rise to viable high-degree chimeras with contribution to the germline. These data show that transcription factor-induced reprogramming leads to the global reversion of the somatic epigenome into an ES-like state. Our results provide a paradigm for studying the epigenetic modifications that accompany nuclear reprogramming and suggest that abnormal epigenetic reprogramming does not pose a problem for the potential therapeutic applications of iPS cells.", "title": "Directly reprogrammed fibroblasts show global epigenetic remodeling and widespread tissue contribution." }, { "docid": "22428640", "text": "Embryonic stem cells have an unlimited potential for self-renewal yet are pluripotent, capable of differentiating into three different germ layers and ultimately into multiple cell lineages. Key pluripotency specific factors maintain an undifferentiated ES cell phenotype while lineage specific factors work in opposition to promote cell specialization. In addition to these important transcriptional regulators, epigenetic modifiers play a defining role in regulating the balance between pluripotency and differentiation by promoting changes in chromatin structure.", "title": "Chromatin remodeling in embryonic stem cells: regulating the balance between pluripotency and differentiation." }, { "docid": "30884033", "text": "Deciphering the molecular basis of stem cell pluripotency is fundamental to the understanding of stem cell biology, early embryonic development, and to the clinical application of regenerative medicine. We report here that the molecular chaperone heat shock protein 90 (Hsp90) is essential for mouse embryonic stem cell (ESC) pluripotency through regulating multiple pluripotency factors, including Oct4, Nanog, and signal transducer and activator of transcription 3. Inhibition of Hsp90 by either 17-N-Allylamino-17-demethoxygeldanamycin or miRNA led to ESC differentiation. Overexpression of Hsp90β partially rescued the phenotype; in particular, the levels of Oct4 and Nanog were restored. Notably, Hsp90 associated with Oct4 and Nanog in the same cellular complex and protected them from degradation by the ubiquitin proteasome pathway, suggesting that Oct4 and Nanog are potential novel Hsp90 client proteins. In addition, Hsp90 inhibition reduced the mRNA level of Oct4, but not that of Nanog, indicating that Hsp90 participates in Oct4 mRNA processing or maturation. Hsp90 inhibition also increased expression of some protein markers for mesodermal lineages, implying that Hsp90 suppresses mesodermal differentiation from ESCs. These findings support a new role for Hsp90 in maintaining ESC pluripotency by sustaining the level of multiple pluripotency factors, particularly Oct4 and Nanog.", "title": "Regulation of embryonic stem cell pluripotency by heat shock protein 90." }, { "docid": "4457834", "text": "The transfer of somatic cell nuclei into oocytes can give rise to pluripotent stem cells that are consistently equivalent to embryonic stem cells, holding promise for autologous cell replacement therapy. Although methods to induce pluripotent stem cells from somatic cells by transcription factors are widely used in basic research, numerous differences between induced pluripotent stem cells and embryonic stem cells have been reported, potentially affecting their clinical use. Because of the therapeutic potential of diploid embryonic stem-cell lines derived from adult cells of diseased human subjects, we have systematically investigated the parameters affecting efficiency of blastocyst development and stem-cell derivation. Here we show that improvements to the oocyte activation protocol, including the use of both kinase and translation inhibitors, and cell culture in the presence of histone deacetylase inhibitors, promote development to the blastocyst stage. Developmental efficiency varied between oocyte donors, and was inversely related to the number of days of hormonal stimulation required for oocyte maturation, whereas the daily dose of gonadotropin or the total number of metaphase II oocytes retrieved did not affect developmental outcome. Because the use of concentrated Sendai virus for cell fusion induced an increase in intracellular calcium concentration, causing premature oocyte activation, we used diluted Sendai virus in calcium-free medium. Using this modified nuclear transfer protocol, we derived diploid pluripotent stem-cell lines from somatic cells of a newborn and, for the first time, an adult, a female with type 1 diabetes.", "title": "Human oocytes reprogram adult somatic nuclei of a type 1 diabetic to diploid pluripotent stem cells" }, { "docid": "42106119", "text": "The transcription factor Oct4 is key in embryonic stem cell identity and reprogramming. Insight into its partners should illuminate how the pluripotent state is established and regulated. Here, we identify a considerably expanded set of Oct4-binding proteins in mouse embryonic stem cells. We find that Oct4 associates with a varied set of proteins including regulators of gene expression and modulators of Oct4 function. Half of its partners are transcriptionally regulated by Oct4 itself or other stem cell transcription factors, whereas one-third display a significant change in expression upon cell differentiation. The majority of Oct4-associated proteins studied to date show an early lethal phenotype when mutated. A fraction of the human orthologs is associated with inherited developmental disorders or causative of cancer. The Oct4 interactome provides a resource for dissecting mechanisms of Oct4 function, enlightening the basis of pluripotency and development, and identifying potential additional reprogramming factors.", "title": "An Expanded Oct4 Interaction Network: Implications for Stem Cell Biology, Development, and Disease" }, { "docid": "13759726", "text": "The reconstruction of gene regulatory networks underlying cell differentiation from high-throughput gene expression and chromatin data remains a challenge. Here, we derive dynamic gene regulatory networks for human myeloid differentiation using a 5-day time series of RNA-seq and ATAC-seq data. We profile HL-60 promyelocytes differentiating into macrophages, neutrophils, monocytes, and monocyte-derived macrophages. We find a rapid response in the expression of key transcription factors and lineage markers that only regulate a subset of their targets at a given time, which is followed by chromatin accessibility changes that occur later along with further gene expression changes. We observe differences between promyelocyte- and monocyte-derived macrophages at both the transcriptional and chromatin landscape level, despite using the same differentiation stimulus, which suggest that the path taken by cells in the differentiation landscape defines their end cell state. More generally, our approach of combining neighboring time points and replicates to achieve greater sequencing depth can efficiently infer footprint-based regulatory networks from long series data.", "title": "Dynamic Gene Regulatory Networks of Human Myeloid Differentiation." }, { "docid": "23418635", "text": "Pluripotent stem cells exist in naive and primed states, epitomized by mouse embryonic stem cells (ESCs) and the developmentally more advanced epiblast stem cells (EpiSCs; ref. ). In the naive state of ESCs, the genome has an unusual open conformation and possesses a minimum of repressive epigenetic marks. In contrast, EpiSCs have activated the epigenetic machinery that supports differentiation towards the embryonic cell types. The transition from naive to primed pluripotency therefore represents a pivotal event in cellular differentiation. But the signals that control this fundamental differentiation step remain unclear. We show here that paracrine and autocrine Wnt signals are essential self-renewal factors for ESCs, and are required to inhibit their differentiation into EpiSCs. Moreover, we find that Wnt proteins in combination with the cytokine LIF are sufficient to support ESC self-renewal in the absence of any undefined factors, and support the derivation of new ESC lines, including ones from non-permissive mouse strains. Our results not only demonstrate that Wnt signals regulate the naive-to-primed pluripotency transition, but also identify Wnt as an essential and limiting ESC self-renewal factor.", "title": "Embryonic stem cells require Wnt proteins to prevent differentiation to epiblast stem cells" }, { "docid": "26612216", "text": "ATP-dependent chromatin remodeling complexes are a notable group of epigenetic modifiers that use the energy of ATP hydrolysis to change the structure of chromatin, thereby altering its accessibility to nuclear factors. BAF250a (ARID1a) is a unique and defining subunit of the BAF chromatin remodeling complex with the potential to facilitate chromosome alterations critical during development. Our studies show that ablation of BAF250a in early mouse embryos results in developmental arrest (about embryonic day 6.5) and absence of the mesodermal layer, indicating its critical role in early germ-layer formation. Moreover, BAF250a deficiency compromises ES cell pluripotency, severely inhibits self-renewal, and promotes differentiation into primitive endoderm-like cells under normal feeder-free culture conditions. Interestingly, this phenotype can be partially rescued by the presence of embryonic fibroblast cells. DNA microarray, immunostaining, and RNA analyses revealed that BAF250a-mediated chromatin remodeling contributes to the proper expression of numerous genes involved in ES cell self-renewal, including Sox2, Utf1, and Oct4. Furthermore, the pluripotency defects in BAF250a mutant ES cells appear to be cell lineage-specific. For example, embryoid body-based analyses demonstrated that BAF250a-ablated stem cells are defective in differentiating into fully functional mesoderm-derived cardiomyocytes and adipocytes but are capable of differentiating into ectoderm-derived neurons. Our results suggest that BAF250a is a key component of the gene regulatory machinery in ES cells controlling self-renewal, differentiation, and cell lineage decisions.", "title": "ES cell pluripotency and germ-layer formation require the SWI/SNF chromatin remodeling component BAF250a." }, { "docid": "5085118", "text": "OBJECTIVE We recently demonstrated that primitive neural crest-derived (NC) cells migrate from the cardiac neural crest during embryonic development and remain in the heart as dormant stem cells, with the capacity to differentiate into various cell types, including cardiomyocytes. Here, we examined the migration and differentiation potential of these cells on myocardial infarction (MI). \n METHODS AND RESULTS We obtained double-transgenic mice by crossing protein-0 promoter-Cre mice with Floxed-enhanced green fluorescent protein mice, in which the NC cells express enhanced green fluorescent protein. In the neonatal heart, NC stem cells (NCSCs) were localized predominantly in the outflow tract, but they were also distributed in a gradient from base to apex throughout the ventricular myocardium. Time-lapse video analysis revealed that the NCSCs were migratory. Some NCSCs persisted in the adult heart. On MI, NCSCs accumulated at the ischemic border zone area (BZA), which expresses monocyte chemoattractant protein-1 (MCP-1). Ex vivo cell migration assays demonstrated that MCP-1 induced NCSC migration and that this chemotactic effect was significantly depressed by an anti-MCP-1 antibody. Small NC cardiomyocytes first appeared in the BZA 2 weeks post-MI and gradually increased in number thereafter. \n CONCLUSIONS These results suggested that NCSCs migrate into the BZA via MCP-1/CCR2 signaling and contribute to the provision of cardiomyocytes for cardiac regeneration after MI.", "title": "Neural crest-derived stem cells migrate and differentiate into cardiomyocytes after myocardial infarction." }, { "docid": "52868579", "text": "Epigenetic genome modifications are thought to be important for specifying the lineage and developmental stage of cells within a multicellular organism. Here, we show that the epigenetic profile of pluripotent embryonic stem cells (ES) is distinct from that of embryonic carcinoma cells, haematopoietic stem cells (HSC) and their differentiated progeny. Silent, lineage-specific genes replicated earlier in pluripotent cells than in tissue-specific stem cells or differentiated cells and had unexpectedly high levels of acetylated H3K9 and methylated H3K4. Unusually, in ES cells these markers of open chromatin were also combined with H3K27 trimethylation at some non-expressed genes. Thus, pluripotency of ES cells is characterized by a specific epigenetic profile where lineage-specific genes may be accessible but, if so, carry repressive H3K27 trimethylation modifications. H3K27 methylation is functionally important for preventing expression of these genes in ES cells as premature expression occurs in embryonic ectoderm development (Eed)-deficient ES cells. Our data suggest that lineage-specific genes are primed for expression in ES cells but are held in check by opposing chromatin modifications.", "title": "Chromatin signatures of pluripotent cell lines." } ]

[ { "docid": "21498497", "text": "Leprosy enables investigation of mechanisms by which the innate immune system contributes to host defense against infection, because in one form, the disease progresses, and in the other, the infection is limited. We report that Toll-like receptor (TLR) activation of human monocytes induces rapid differentiation into two distinct subsets: DC-SIGN+ CD16+ macrophages and CD1b+ DC-SIGN− dendritic cells. DC-SIGN+ phagocytic macrophages were expanded by TLR-mediated upregulation of interleukin (IL)-15 and IL-15 receptor. CD1b+ dendritic cells were expanded by TLR-mediated upregulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) and its receptor, promoted T cell activation and secreted proinflammatory cytokines. Whereas DC-SIGN+ macrophages were detected in lesions and after TLR activation in all leprosy patients, CD1b+ dendritic cells were not detected in lesions or after TLR activation of peripheral monocytes in individuals with the progressive lepromatous form, except during reversal reactions in which bacilli were cleared by T helper type 1 (TH1) responses. In tuberculoid lepromatous lesions, DC-SIGN+ cells were positive for macrophage markers, but negative for dendritic cell markers. Thus, TLR-induced differentiation of monocytes into either macrophages or dendritic cells seems to crucially influence effective host defenses in human infectious disease.", "title": "TLR activation triggers the rapid differentiation of monocytes into macrophages and dendritic cells" } ]

[ { "docid": "8596357", "text": "Functional disruption of dendritic cells (DC) is an important strategy for viral pathogens to evade host defences. In this context, porcine circovirus type 2 (PCV2), a single-stranded DNA virus, impairs plasmacytoid DC (pDC) and conventional DC activation by certain viruses or Toll-like receptor (TLR) ligands. This inhibitory capacity is associated with the viral DNA, but the impairment does not affect all signalling cascades; TLR7 ligation by small chemical molecules will still induce interleukin-6 (IL-6) and tumour necrosis factor-α secretion, but not interferon-α or IL-12. In this study, the molecular mechanisms by which silencing occurs were investigated. PP2, a potent inhibitor of the Lyn and Hck kinases, produced a similar profile to the PCV2 DNA interference with cytokine secretion by pDC, efficiently inhibiting cell activation induced through TLR9, but not TLR7, ligation. Confocal microscopy and cytometry analysis strongly suggested that PCV2 DNA impairs actin polymerization and endocytosis in pDC and monocyte-derived DC, respectively. Altogether, this study delineates for the first time particular molecular mechanisms involved in PCV2 interference with DC danger recognition, which may be responsible for the virus-induced immunosuppression observed in infected pigs.", "title": "Porcine circovirus type 2 DNA influences cytoskeleton rearrangements in plasmacytoid and monocyte-derived dendritic cells." }, { "docid": "28015516", "text": "Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by a breakdown of tolerance to nuclear antigens and the development of immune complexes. Genomic approaches have shown that human SLE leukocytes homogeneously express type I interferon (IFN)-induced and neutrophil-related transcripts. Increased production and/or bioavailability of IFN-α and associated alterations in dendritic cell (DC) homeostasis have been linked to lupus pathogenesis. Although neutrophils have long been shown to be associated with lupus, their potential role in disease pathogenesis remains elusive. Here, we show that mature SLE neutrophils are primed in vivo by type I IFN and die upon exposure to SLE-derived anti-ribonucleoprotein antibodies, releasing neutrophil extracellular traps (NETs). SLE NETs contain DNA as well as large amounts of LL37 and HMGB1, neutrophil proteins that facilitate the uptake and recognition of mammalian DNA by plasmacytoid DCs (pDCs). Indeed, SLE NETs activate pDCs to produce high levels of IFN-α in a DNA- and TLR9 (Toll-like receptor 9)-dependent manner. Our results reveal an unsuspected role for neutrophils in SLE pathogenesis and identify a novel link between nucleic acid-recognizing antibodies and type I IFN production in this disease.", "title": "Netting neutrophils are major inducers of type I IFN production in pediatric systemic lupus erythematosus." }, { "docid": "24707550", "text": "Macrophages play a pivotal role in innate and acquired immune responses to Schistosoma mansoni. Classical (M1) or alternative (M2) activation states of these cells further delineate their roles in tissue damage through innate immunity or fibrotic remodeling, respectively. In the present study, we addressed the following question: Does systemic Th2-type cytokine polarization evoked by S. mansoni affect macrophage differentiation and activation? To this end, we analyzed bone marrow-derived macrophages from mice with S. mansoni egg-induced pulmonary granulomas and unchallenged (or naïve) mice to determine their activation state and their response to specific TLR agonists, including S. mansoni egg antigens. Unlike naïve macrophages, macrophages from Th2-polarized mice constitutively expressed significantly higher \"found in inflammatory zone-1\" (FIZZ1) and ST2 (M2 markers) and significantly lower NO synthase 2, CCL3, MIP-2, TNF-alpha, and IL-12 (M1 markers). Also, compared with naïve macrophages, Th2-polarized macrophages exhibited enhanced responses to the presence of specific TLR agonists, which consistently induced significantly higher levels of gene and protein levels for M2 and M1 markers in these cells. Together, these data show that signals received by bone marrow precursors during S. mansoni egg-induced granuloma responses dynamically alter the development of macrophages and enhance the TLR responsiveness of these cells, which may ultimately have a significant effect on the pulmonary granulomatous response.", "title": "A systemic granulomatous response to Schistosoma mansoni eggs alters responsiveness of bone-marrow-derived macrophages to Toll-like receptor agonists." }, { "docid": "23273454", "text": "Eleven mammalian toll-like receptors (TLRs 1-11) have been identified to date and are known to play a crucial role in the regulation of immune responses; however, the factors that regulate TLR expression and function in vivo are poorly understood. Therefore, in the present study, we investigated the physiological regulation of TLR expression and function in humans. To examine the influence of diurnal rhythmicity on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers (n = 8) at time points coinciding with the peak and nadir in the endogenous circulating cortisol concentration. While no diurnal rhythmicity in the expression of TLRs 1, 2, 4 or 9 was observed, the upregulation of costimulatory (CD80 and CD86) and antigen-presenting (MHC class II) molecules on CD14(+) monocytes following activation with specific TLR ligands was greater (P < 0.05) in samples obtained in the evening compared with the morning. To examine the influence of physical stress on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers (n = 11) at rest and following 1.5 h of strenuous exercise in the heat (34 degrees C). Strenuous exercise resulted in a decrease (P < 0.005) in the expression of TLRs 1, 2 and 4 on CD14(+) monocytes. Furthermore, the upregulation of CD80, CD86, MHC class II and interleukin-6 by CD14(+) monocytes following activation with specific TLR ligands was decreased (P < 0.05) in samples obtained following exercise compared with at rest. These results demonstrate that TLR function is subject to modulation under physiological conditions in vivo and provide evidence for the role of immunomodulatory hormones in the regulation of TLR function.", "title": "The physiological regulation of toll-like receptor expression and function in humans." }, { "docid": "14644164", "text": "TLR sense microbial infections, and control activation of immune responses. Dendritic cells, macrophages, and B lymphocytes express TLR and the TLR-signaling adaptor protein MyD88. The impact of TLR-activated B cells on T cell-mediated inflammation is unknown. In this study, we have used mice carrying B cell-restricted deficiencies in MyD88 or in distinct TLR to examine the impact of TLR-activated B cells on a T cell-mediated autoimmune disease, experimental autoimmune encephalomyelitis (EAE). We demonstrate that TLR-signaling in B cells suppresses inflammatory T cell responses (both Th1 and Th17), and stimulates recovery from EAE. Only certain TLR are required on B cells for resolution of EAE, and these are dispensable for disease initiation, indicating that a category of TLR agonists preferentially triggers a suppressive function in B cells and thereby limits autoimmune disease. The TLR agonists controlling the regulatory function of B cells are provided by components of Mycobacterium tuberculosis present in the adjuvant. Thus, MyD88 signaling in B cells antagonizes MyD88 signaling in other cells, which drives differentiation of Th17 cells and is required for induction of EAE. Altogether, our data indicate that B cells link recognition of microbial products via TLR to suppression of a T cell-mediated autoimmune disease.", "title": "TLR-activated B cells suppress T cell-mediated autoimmunity." }, { "docid": "3616843", "text": "BACKGROUND Although Toll-like receptor 4 (TLR-4) is involved in monocyte activation in patients with accelerated forms of atherosclerosis, the relationship between the expression of TLR-4 on circulating monocytes and coronary plaque vulnerability has not previously been evaluated. We investigated this relationship using 64-slice multidetector computed tomography (MDCT) in patients with stable angina pectoris (SAP).Methods and Results:We enrolled 65 patients with SAP who underwent MDCT. Three monocyte subsets (CD14++CD16-, CD14++CD16+, and CD14+CD16+) and expression of TLR-4 were measured by flow cytometry. Intracoronary plaques were assessed by 64-slice MDCT. We defined vulnerability of intracoronary plaques according to the presence of positive remodeling (remodeling index >1.05) and/or low CT attenuation (<35 HU). The circulating CD14++CD16+monocytes more frequently expressed TLR-4 than CD14++CD16-and CD14+CD16+monocytes (P<0.001). The relative proportion of the expression of TLR-4 on CD14++CD16+monocytes was significantly greater in patients with vulnerable plaque compared with those without (10.4 [4.1-14.5] % vs. 4.5 [2.8-7.8] %, P=0.012). In addition, the relative proportion of TLR-4 expression on CD14++CD16+monocytes positively correlated with the remodeling index (r=0.28, P=0.025) and negatively correlated with CT attenuation value (r=-0.31, P=0.013). \n CONCLUSIONS Upregulation of TLR-4 on CD14++CD16+monocytes might be associated with coronary plaque vulnerability in patients with SAP.", "title": "Association of Toll-Like Receptor 4 on Human Monocyte Subsets and Vulnerability Characteristics of Coronary Plaque as Assessed by 64-Slice Multidetector Computed Tomography." }, { "docid": "5798227", "text": "Bacterial lipopolysaccharide (LPS) triggers innate immune responses through Toll-like receptor (TLR) 4. We show here that the suppressor of cytokine-signaling-1 (SOCS1/JAB) is rapidly induced by LPS and negatively regulates LPS signaling. SOCS1(+/-) mice or SOCS1(-/-) mice with interferon-gamma (IFNgamma)-deficient background were more sensitive to LPS-induced lethal effects than were wild-type littermates. LPS-induced NO(2)(-) synthesis and TNFalpha production were augmented in SOCS1(-/-) macrophages. Furthermore, LPS tolerance, a protection mechanism against endotoxin shock, was also strikingly reduced in SOCS1(-/-) cells. LPS-induced I-kappaB and p38 phosphorylation was upregulated in SOCS1(-/-) macrophages, and forced expression of SOCS1 suppressed LPS-induced NF-kappaB activation. Thus, SOCS1 directly suppresses TLR4 signaling and modulates innate immunity.", "title": "SOCS1/JAB is a negative regulator of LPS-induced macrophage activation." }, { "docid": "46135768", "text": "Endosomal Toll-like receptors (TLRs) 7 and 9 recognize viral pathogens and induce signals leading to the activation of nuclear factor κB (NF-κB)-dependent proinflammatory cytokines and interferon regulatory factor 7 (IRF7)-dependent type I interferons (IFNs). Recognition of viral nucleic acids by TLR9 requires its cleavage in the endolysosomal compartment. Here, we show that TLR9 signals leading to the activation of type I IFN, but not proinflammatory cytokine genes, require TLR9 trafficking from endosomes to a specialized lysosome-related organelle. Furthermore, we identify adapter protein-3 as the protein complex responsible for the trafficking of TLR9 to this subcellular compartment. Our results reveal an intracellular mechanism for bifurcation of TLR9 signals by selective receptor trafficking within the endosomal system.", "title": "Materials and Methods Figs. S1 to S15 References Supporting Online Materials" }, { "docid": "31313782", "text": "Patients with idiopathic pulmonary fibrosis (IPF) have a higher incidence of lung cancer. The role of Toll-like receptors (TLRs), a key component of the innate immunity, in interstitial lung diseases (ILDs) and lung cancer pathogenesis is not clarified. TLR2, TLR3, TLR4, TLR7, TLR8 and TLR9 mRNA expression was quantitatively measured by real-time reverse transcriptase polymerase chain reaction (RT-PCR) in bronchoalveolar lavage fluid (BALF) of 16 IPF patients, 16 non-small cell lung cancer (NSCLC) patients and 9 control subjects. TLR2, TLR3, TLR4 and TLR9 protein expression was assessed on BALF T-lymphocytes using flow cytometry. TLR3 mRNA expression was significantly higher in NSCLC compared to IPF (p=0.023) and controls (p=0.001). TLR7 mRNA expression levels were significantly higher in both NSCLC and IPF groups compared to controls (p=0.029, p=0.009). TLR9 expression at the mRNA level was significantly higher in both NSCLC and IPF groups compared to controls (p=0.01, p=0.001). Finally, TLR2 mRNA expression was significantly higher in IPF patients compared to controls (p=0.042). Flow cytometry revealed decreased TLR3 and TLR9 expression in IPF patients compared to the NSCLC group (p=0.02, p=0.014) and decreased TLR9 expression in IPF compared with the controls (p=0.04). TLR2 protein expression was significantly higher in IPF patients compared to NSCLC (p=0.04). Increased expression of endosomal TLRs in NSCLC patients and elevated expression of TLR2 in pulmonary fibrosis are the main results of this study. These results do not provide support for a common TLR pathway hypothesis between NSCLC and IPF.", "title": "Expression profiles of Toll-like receptors in non-small cell lung cancer and idiopathic pulmonary fibrosis." }, { "docid": "51952430", "text": "The toll-like receptor (TLR) and interleukin (IL)-1 family of receptors share several signaling components, including the most upstream adapter, MyD88. We previously reported the discovery of B cell adapter for phosphoinositide 3-kinase (BCAP) as a novel toll-IL-1 receptor homology domain-containing adapter that regulates inflammatory responses downstream of TLR signaling. Here we find that BCAP plays a critical role downstream of both IL-1 and IL-18 receptors to regulate T helper (Th) 17 and Th1 cell differentiation, respectively. Absence of T cell intrinsic BCAP did not alter development of naturally arising Th1 and Th17 lineages but led to defects in differentiation to pathogenic Th17 lineage cells. Consequently, mice that lack BCAP in T cells had reduced susceptibility to experimental autoimmune encephalomyelitis. More importantly, we found that BCAP is critical for IL-1R-induced phosphoinositide 3-kinase-Akt-mechanistic target of rapamycin (mTOR) activation, and minimal inhibition of mTOR completely abrogated IL-1β-induced differentiation of pathogenic Th17 cells, mimicking BCAP deficiency. This study establishes BCAP as a critical link between IL-1R and the metabolic status of activated T cells that ultimately regulates the differentiation of inflammatory Th17 cells.", "title": "BCAP links IL-1R to the PI3K–mTOR pathway and regulates pathogenic Th17 cell differentiation" }, { "docid": "24042363", "text": "Agonist-induced dimerization of TLR4 Toll/IL-1R (TIR) domains initiates intracellular signaling. Therefore, identification of the TLR4-TIR dimerization interface is one key to the rational design of therapeutics that block TLR4 signaling. A library of cell-permeating decoy peptides, each of which represents a nonfragmented patch of the TLR4 TIR surface, was designed such that the peptides entirely encompass the TLR4 TIR surface. Each peptide was synthesized in tandem with a cell-permeating Antennapedia homeodomain sequence and tested for the ability to inhibit early cytokine mRNA expression and MAPK activation in LPS-stimulated primary murine macrophages. Five peptides--4R1, 4R3, 4BB, 4R9, and 4αE--potently inhibited all manifestations of TLR4, but not TLR2 signaling. When tested for their ability to bind directly to TLR4 TIR by Förster resonance energy transfer using time-resolved fluorescence spectroscopy, Bodipy-TMR-X-labeled 4R1, 4BB, and 4αE quenched fluorescence of TLR4-Cerulean expressed in HeLa or HEK293T cells, whereas 4R3 was partially active, and 4R9 was least active. These findings suggest that the area between the BB loop of TLR4 and its fifth helical region mediates TLR4 TIR dimerization. Moreover, our data provide direct evidence for the utility of the decoy peptide approach, in which peptides representing various surface-exposed segments of a protein are initially probed for the ability to inhibit protein function, and then their specific targets are identified by Förster resonance energy transfer to define recognition sites in signaling proteins that may be targeted therapeutically to disrupt functional transient protein interactions.", "title": "Targeting TLR4 signaling by TLR4 Toll/IL-1 receptor domain-derived decoy peptides: identification of the TLR4 Toll/IL-1 receptor domain dimerization interface." }, { "docid": "17023584", "text": "The incidence of sepsis is increasing over time, along with an increased risk of dying from the condition. Sepsis care costs billions annually in the United States. Death from sepsis is understood to be a complex process, driven by a lack of normal immune homeostatic functions and excessive production of proinflammatory cytokines, which leads to multi-organ failure. The Toll-like receptor (TLR) family, one of whose members was initially discovered in Drosophila, performs an important role in the recognition of microbial pathogens. These pattern recognition receptors (PRRs), upon sensing invading microorganisms, activate intracellular signal transduction pathways. NOD signaling is also involved in the recognition of bacteria and acts synergistically with the TLR family in initiating an efficient immune response for the eradication of invading microbial pathogens. TLRs and NOD1/NOD2 respond to different pathogen-associated molecular patterns (PAMPs). Modulation of both TLR and NOD signaling is an area of research that has prompted much excitement and debate as a therapeutic strategy in the management of sepsis. Molecules targeting TLR and NOD signaling pathways exist but regrettably thus far none have proven efficacy from clinical trials.", "title": "Current knowledge and future directions of TLR and NOD signaling in sepsis" }, { "docid": "12658073", "text": "The gut microbiota has been proposed as an environmental factor that affects the development of metabolic and inflammatory diseases in mammals. Recent reports indicate that gut bacteria-derived lipopolysaccharide (LPS) can initiate obesity and insulin resistance in mice; however, the molecular interactions responsible for microbial regulation of host metabolism and mediators of inflammation have not been studied in detail. Hepatic serum amyloid A (SAA) proteins are markers and proposed mediators of inflammation that exhibit increased levels in serum of insulin-resistant mice. Adipose tissue-derived SAA3 displays monocyte chemotactic activity and may play a role in metabolic inflammation associated with obesity and insulin resistance. To investigate a potential mechanistic link between the intestinal microbiota and induction of proinflammatory host factors, we performed molecular analyses of germ-free, conventionally raised and genetically modified Myd88-/- mouse models. SAA3 expression was determined to be significantly augmented in adipose (9.9+/-1.9-fold; P<0.001) and colonic tissue (7.0+/-2.3-fold; P<0.05) by the presence of intestinal microbes. In the colon, we provided evidence that SAA3 is partially regulated through the Toll-like receptor (TLR)/MyD88/NF-kappaB signaling axis. We identified epithelial cells and macrophages as cellular sources of SAA3 in the colon and found that colonic epithelial expression of SAA3 may be part of an NF-kappaB-dependent response to LPS from gut bacteria. In vitro experiments showed that LPS treatments of both epithelial cells and macrophages induced SAA3 expression (27.1+/-2.5-fold vs. 1.6+/-0.1-fold, respectively). Our data suggest that LPS, and potentially other products of the indigenous gut microbiota, might elevate cytokine expression in tissues and thus exacerbate chronic low-grade inflammation observed in obesity.", "title": "Regulation of Serum Amyloid A3 (SAA3) in Mouse Colonic Epithelium and Adipose Tissue by the Intestinal Microbiota" }, { "docid": "13778710", "text": "Chemokine-like receptor 1 (CMKLR1), also known as ChemR23, and chemokine (C-C motif) receptor-like 2 (CCRL2) are 7-transmembrane receptors that were cloned in the late 1990s based on their homology to known G-protein-coupled receptors. They were previously orphan receptors without any known biological roles; however, recent studies identified ligands for these receptors and their functions have begun to be unveiled. The plasma protein-derived chemoattractant chemerin is a ligand for CMKLR1 and activation of CMKLR1 with chemerin induces the migration of macrophages and dendritic cells (DCs) in vitro, suggesting a proinflammatory role. However, in vivo studies using CMKLR-deficient mice suggest an anti-inflammatory role for this receptor, possibly due to the recruitment of tolerogenic plasmacytoid DCs. Chemerin/CMKLR1 interaction also promotes adipogenesis and angiogenesis. The anti-inflammatory lipid mediator, resolving E1, is another CMKLR1 ligand and it inhibits leukocyte infiltration and proinflammatory gene expression. These divergent results suggest that CMKLR1 is a multifunctional receptor. The chemokine CCL5 and CCL19 are reported to bind to CCRL2. Like Duffy antigen for chemokine receptor (DARC), D6 and CCX-CKR, CCRL2 does not signal, but it constitutively recycles, potentially reducing local concentration of CCL5 and CCL19 and subsequent immune responses. Surprisingly, chemerin, a ligand for CMKLR1, is a ligand for CCRL2. CCRL2 binds chemerin and increases local chemerin concentration to efficiently present it to CMKLR1 on nearby cells, providing a link between CCRL2 and CMKLR1. Although these findings suggest an anti-inflammatory role, a recent study using CCRL2-deficient mice indicates a proinflammatory role; thus, CCRL2 may also be multifunctional. Further studies using CMKLR1- or CCRL2-deficient mice are needed to further define the role of these receptors in immune responses and other cellular processes.", "title": "Chemokine-like receptor 1 (CMKLR1) and chemokine (C-C motif) receptor-like 2 (CCRL2); two multifunctional receptors with unusual properties." }, { "docid": "2587396", "text": "Background: Atherosclerosis is characterized by infiltration of inflammatory cells from circulating blood. Blood cell activation could play an important role in plaque formation. Methods: We analyzed the relationship between blood cellular markers and quantitative measures of carotid wall components in 1,546 participants from the ARIC (Atherosclerosis Risk in Communities) Carotid MRI Study. Carotid imaging was performed using a gadolinium contrast-enhanced MRI and cellular phenotyping by flow cytometry. Results: Monocyte Toll-like receptor (TLR)-2 is associated with larger plaques, while CD14, myeloperoxidase, and TLR-4 associate with smaller. Platelet CD40L is associated with smaller plaques and thinner caps, while P-selectin is associated with smaller core size. Conclusions: Blood cell activation is significantly associated with atherosclerotic changes of the carotid wall.", "title": "Association of Blood Monocyte and Platelet Markers with Carotid Artery Characteristics: The Atherosclerosis Risk in Communities Carotid MRI Study" }, { "docid": "9159125", "text": "Macrophages produce a large amount of PGE(2) during inflammation. This lipid mediator modulates various immune responses. PGE(2) acts on macrophages and inhibits production of cytokines such as TNF-alpha and IL-12. Membrane-bound glutathione-dependent PGE(2) synthase (mPGES) has been shown to be a terminal enzyme of the cyclooxygenase-2-mediated PGE(2) biosynthesis. Here we identified mPGES as a molecule that is induced by LPS in macrophages. The expression of mPGES was not induced by LPS in mice lacking Toll-like receptor 4 or MyD88. Furthermore, mice deficient in NF-IL6 showed neither induction of mPGES nor biosynthesis of PGE(2) in response to LPS, indicating that mPGES expression in response to LPS is regulated by a Toll-like receptor 4/MyD88/NF-IL6-dependent signaling pathway. We generated mPGES-deficient mice and investigated the role of mPGES in vivo. The mice showed no augmentation of the PGE(2) production in response to LPS. However, they were not impaired in the LPS-induced production of inflammatory cytokines and showed normal response to the LPS-induced shock. Thus, mPGES is critically involved in the biosynthesis of PGE(2) induced by LPS, but is dispensable for the modulation of inflammatory responses.", "title": "Lipopolysaccharide-dependent prostaglandin E(2) production is regulated by the glutathione-dependent prostaglandin E(2) synthase gene induced by the Toll-like receptor 4/MyD88/NF-IL6 pathway." }, { "docid": "188911", "text": "Antigen-presenting, major histocompatibility complex (MHC) class II-rich dendritic cells are known to arise from bone marrow. However, marrow lacks mature dendritic cells, and substantial numbers of proliferating less-mature cells have yet to be identified. The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II-negative precursors in marrow. A key step is to remove the majority of nonadherent, newly formed granulocytes by gentle washes during the first 2-4 d of culture. This leaves behind proliferating clusters that are loosely attached to a more firmly adherent \"stroma. \" At days 4-6 the clusters can be dislodged, isolated by 1-g sedimentation, and upon reculture, large numbers of dendritic cells are released. The latter are readily identified on the basis of their distinct cell shape, ultrastructure, and repertoire of antigens, as detected with a panel of monoclonal antibodies. The dendritic cells express high levels of MHC class II products and act as powerful accessory cells for initiating the mixed leukocyte reaction. Neither the clusters nor mature dendritic cells are generated if macrophage colony-stimulating factor rather than granulocyte/macrophage colony-stimulating factor (GM-CSF) is applied. Therefore, GM-CSF generates all three lineages of myeloid cells (granulocytes, macrophages, and dendritic cells). Since > 5 x 10(6) dendritic cells develop in 1 wk from precursors within the large hind limb bones of a single animal, marrow progenitors can act as a major source of dendritic cells. This feature should prove useful for future molecular and clinical studies of this otherwise trace cell type.", "title": "Generation of large numbers of dendritic cells from mouse bone marrow cultures supplemented with granulocyte/macrophage colony-stimulating factor" }, { "docid": "25453683", "text": "OBJECTIVE T cell immunoglobulin and mucin domain (Tim) proteins are expressed by numerous immune cells, recognize phosphatidylserine on apoptotic cells, and function as costimulators or coinhibitors. Tim-1 is expressed by activated T cells but is also found on dendritic cells and B cells. Tim-4, present on macrophages and dendritic cells, plays a critical role in apoptotic cell clearance, regulates the number of phosphatidylserine-expressing activated T cells, and is genetically associated with low low-density lipoprotein and triglyceride levels. Because these functions of Tim-1 and Tim-4 could affect atherosclerosis, their modulation has potential therapeutic value in cardiovascular disease. APPROACH AND RESULTS ldlr(-/-) mice were fed a high-fat diet for 4 weeks while being treated with control (rat immunoglobulin G1) or anti-Tim-1 (3D10) or -Tim-4 (21H12) monoclonal antibodies that block phosphatidylserine recognition and phagocytosis. Both anti-Tim-1 and anti-Tim-4 treatments enhanced atherosclerosis by 45% compared with controls by impairment of efferocytosis and increasing aortic CD4(+)T cells. Consistently, anti-Tim-4-treated mice showed increased percentages of activated T cells and late apoptotic cells in the circulation. Moreover, in vitro blockade of Tim-4 inhibited efferocytosis of oxidized low-density lipoprotein-induced apoptotic macrophages. Although anti-Tim-4 treatment increased T helper cell (Th)1 and Th2 responses, anti-Tim-1 induced Th2 responses but dramatically reduced the percentage of regulatory T cells. Finally, combined blockade of Tim-1 and Tim-4 increased atherosclerotic lesion size by 59%. \n CONCLUSIONS Blockade of Tim-4 aggravates atherosclerosis likely by prevention of phagocytosis of phosphatidylserine-expressing apoptotic cells and activated T cells by Tim-4-expressing cells, whereas Tim-1-associated effects on atherosclerosis are related to changes in Th1/Th2 balance and reduced circulating regulatory T cells.", "title": "Blockade of Tim-1 and Tim-4 Enhances Atherosclerosis in Low-Density Lipoprotein Receptor-Deficient Mice." }, { "docid": "14362780", "text": "The role of microRNAs (miRNAs) in infectious diseases is becoming more and more apparent, and the use of miRNAs as a diagnostic tool and their therapeutic application has become the major focus of investigation. The aim of this study was to identify miRNAs involved in the immune signaling of macrophages in response to Arcobacter (A.) butzleri infection, an emerging foodborne pathogen causing gastroenteritis. Therefore, primary human macrophages were isolated and infected, and miRNA expression was studied by means of RNAseq. Analysis of the data revealed the expression of several miRNAs, which were previously associated with bacterial infections such as miR-155, miR-125, and miR-212. They were shown to play a key role in Toll-like receptor signaling where they act as fine-tuners to establish a balanced immune response. In addition, miRNAs which have yet not been identified during bacterial infections such as miR-3613, miR-2116, miR-671, miR-30d, and miR-629 were differentially regulated in A. butzleri-infected cells. Targets of these miRNAs accumulated in pathways such as apoptosis and endocytosis - processes that might be involved in A. butzleri pathogenesis. Our study contributes new findings about the interaction of A. butzleri with human innate immune cells helping to understand underlying regulatory mechanisms in macrophages during infection.", "title": "MicroRNA Response of Primary Human Macrophages to Arcobacter Butzleri Infection" } ]

[ { "docid": "8447873", "text": "BACKGROUND Organophosphorus pesticide (OP) self-poisoning is a major problem in the developing rural world. There is little clinical trial data to guide therapy, hindering the identification of best therapy. Despite the recognition of adverse effects, gastric lavage is commonly done in Asia. We aimed to identify studies assessing its effectiveness. \n METHOD We systematically searched the literature for controlled clinical studies that assessed the effect of gastric lavage in OP pesticide self-poisoning. \n RESULTS All 56 studies identified were Chinese and reported benefit from the intervention studied, including multiple gastric lavages, use of norepinephrine or pralidoxime in the lavage fluid, concurrent treatment with naloxone or scopolamine, insertion of the gastric tube via a laparotomy incision, and lavage later than 12 h post-ingestion. However, only 23 were RCTs and none presented adequate methodology for their quality to be assessed. The patient population and study treatment protocol were not defined - large variation in case fatality in the control arm of the studies (from 4.5 to 93%) suggests marked variation between studies and likely between study arms. No study compared an intervention against a control group receiving no gastric lavage or provided any data to indicate whether a significant quantity of poison was removed. \n CONCLUSION Despite widespread use of multiple gastric lavages for OP pesticide poisoning across Asia, there is currently no high-quality evidence to support its clinical effectiveness. There is a need for studies to identify in which patients and for what duration gastric lavage is able to remove significant quantities of poison. Following these studies, large clinical trials will be required to address the effectiveness and safety of gastric lavage (either single or multiple) in acute OP pesticide poisoning.", "title": "Systematic review of controlled clinical trials of gastric lavage in acute organophosphorus pesticide poisoning." }, { "docid": "3430789", "text": "The present study retrospectively analyzed 19 patients diagnosed with paraquat (PQ) poisoning with the aim to investigate the effect of activated charcoal hemoperfusion on renal function and PQ elimination. The results indicated that 7 patients died and 12 survived. Non-oliguric renal failure occurred in all of the 7 patients who died. Among the 12 surviving patients, 10 had normal renal function and 2 developed non-oliguric renal failure. There was a linear correlation between plasma and urine paraquat concentration prior to and during activated charcoal hemoperfusion. The equation parameters together with the correlation coefficient on admission were as follows: Y=0.5820+1.7348X (R2=0.678; F=35.768; P<0.0001). The equation parameters together with the correlation coefficient were as follows during activated charcoal hemoperfusion: Y=0.6827+1.2649X (R2=0.626; F=50.308; P<0.0001). Therefore, it was concluded that in patients with normal renal function, the elimination kinetics of PQ by the kidneys were only associated with the plasma PQ concentration. Activated charcoal hemoperfusion had little effect on avoiding acute kidney injury in patients with severe PQ poisoning.", "title": "Effect of activated charcoal hemoperfusion on renal function in patients with paraquat poisoning." } ]

[ { "docid": "25104843", "text": "We report on a patient treated with hemoperfusion-hemodialysis (HP-HD) for severe paraquat poisoning. This procedure was adopted since the combination of adsorption and dialysis may improve overall drug removal. On admission blood paraquat was 15.8 micrograms/ml. He received conventional treatment and combined HP-HD which started within 3 hours after ingestion of the chemical and lasted 5 hours. Blood samples were obtained during and after HP-HD. The samples during HP-HD were taken before the charcoal column, between the charcoal column and the artificial kidney and after the artificial kidney. Blood clearances of paraquat were 116 +/- 32 ml/min (n=6) for the charcoal column (HP), 90 +/- 54 ml/min (n=6) for the artificial kidney (HD) and 151 +/- 37 ml/min (n=6) for the combined systems (HP-HD). After HP-HD a limited rebound of blood paraquat level was seen. One day after admission renal and hepatic failure had developed, and the patient died after 5 days. Tissue paraquat levels (microgram/g wet tissue) were: skeletal muscle 9.4, pancreas 6.0, prostate 5.6, thyroid 4.2, lungs 4.0, bone marrow 4.0, kidney 3.1, spleen 2.9, adrenal 2.9, heart 2.8, liver 2.3, stomach and testis below 1.0. Measurements of blood levels demonstrated the efficient clearances of paraquat with HP-HD from the central (plasma) compartment. However, the present results confirmed those previously reported which suggest that the efficiency of short HP-HD in treating severe paraquat poisoning is questionable since paraquat levels in the peripheral (tissue) compartment remain elevated.", "title": "Hemoperfusion-hemodialysis ineffective for paraquat removal in life-threatening poisoning?" }, { "docid": "22547508", "text": "Acute paraquat poisoning is often fatal. Many studies have investigated successful treatment modalities, but no standard treatment yet exists. The purpose of this study was to determine the predictors of survival after acute paraquat poisoning in 602 patients. The paraquat exposure was assessed based on the amount of ingested paraquat and a semiquantitative measure of the urine level of paraquat. Initial clinical parameters including vital signs, hemoglobin, white-blood-cell count, pH, PaCO2, PaO2, blood urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, total bilirubin, amylase, and glucose were obtained at the time of arrival at the emergency room. Outcomes after acute paraquat poisoning were categorized as survivors and nonsurvivors. Multiple logistic regression analysis was applied to assess the predictors of survival after acute paraquat poisoning. Some patients (55.5%) survived after oral ingestion of paraquat, whereas all those exposed to paraquat percutaneous or inhalational route survived. The amount of paraquat (24.5% concentrate of 1,1'-dimethyl-4,4'-bipyridium dichloride) ingested was 45.6 +/- 74.1 mL (mean +/- SD). In addition to degree of paraquat exposure, survival after acute paraquat poisoning was associated with age, respiratory rate, pH, PaCO2, hemoglobin, white-blood-cell count, blood urea nitrogen, amylase, and the number of failed organs in multiple logistic regression analysis. In conclusion, young age, percutaneous or inhalational route, exposure to less paraquat, and lesser degrees of leukocytosis, acidosis, and renal, hepatic, and pancreatic failures on admission are good prognostic factors of survival after acute paraquat poisoning.", "title": "Predictors of survival after acute paraquat poisoning." }, { "docid": "12209494", "text": "BACKGROUND The case-fatality for intentional self-poisoning in the rural developing world is 10-50-fold higher than that in industrialised countries, mostly because of the use of highly toxic pesticides and plants. We therefore aimed to assess whether routine treatment with multiple-dose activated charcoal, to interrupt enterovascular or enterohepatic circulations, offers benefit compared with no charcoal in such an environment. \n METHODS We did an open-label, parallel group, randomised, controlled trial of six 50 g doses of activated charcoal at 4-h intervals versus no charcoal versus one 50 g dose of activated charcoal in three Sri Lankan hospitals. 4632 patients were randomised to receive no charcoal (n=1554), one dose of charcoal (n=1545), or six doses of charcoal (n=1533); outcomes were available for 4629 patients. 2338 (51%) individuals had ingested pesticides, whereas 1647 (36%) had ingested yellow oleander (Thevetia peruviana) seeds. Mortality was the primary outcome measure. Analysis was by intention to treat. The trial is registered with controlled-trials.com as ISRCTN02920054. \n FINDINGS Mortality did not differ between the groups. 97 (6.3%) of 1531 participants in the multiple-dose group died, compared with 105 (6.8%) of 1554 in the no charcoal group (adjusted odds ratio 0.96, 95% CI 0.70-1.33). No differences were noted for patients who took particular poisons, were severely ill on admission, or who presented early. \n INTERPRETATION We cannot recommend the routine use of multiple-dose activated charcoal in rural Asia Pacific; although further studies of early charcoal administration might be useful, effective affordable treatments are urgently needed.", "title": "Multiple-dose activated charcoal in acute self-poisoning: a randomised controlled trial" }, { "docid": "33203108", "text": "INTRODUCTION Paraquat is a commonly ingested poison especially in Southern India. There is no antidote for paraquat poison and consumption is often fatal. The usual cause of death is either acute lung injury or multi-organ failure. AIM To evaluate the role of early haemoperfusion as a therapy in paraquat poisoned patients. MATERIALS AND METHODS This study was a retrospective analysis of patients admitted to a Tertiary Medical College Hospital between January 2012 and December 2015 with history of paraquat consumption, comparing outcomes in those who received only gastric lavage and symptomatic treatment with those who received haemoperfusion as a therapy. The role of early haemoperfusion (≤ 6 hours) vs late haemoperfusion (> 6 hours) in paraquat poisoned patients was also compared. The data of these patients was extracted and analysed with respect to age, sex, mode of treatment, the outcome in patients who received early and late haemoperfusion. \n RESULTS A total of 101 patients were studied out of which 62 died. Deaths were more in those patients who received only gastric lavage with symptomatic treatment as therapy compared to those who received haemoperfusion i.e., 92.1% vs 42.9% respectively. We also found that, the survival rate was better in patients who received early haemoperfusion. \n CONCLUSION Early haemoperfusion was helpful in the management of severe paraquat poisoning and improved the survival rate in these patients.", "title": "Golden Hours in Severe Paraquat Poisoning-The Role of Early Haemoperfusion Therapy." }, { "docid": "19132741", "text": "Paraquat, a quarternary nitrogen herbicide, is a highly toxic compound for humans and animals and many cases of acute poisoning and death have been reported over the past few decades. The mechanisms of paraquat toxicity involve: the generation of the superoxide anion, which can lead to the formation of more toxic reactive oxygen species, such as hydrogen peroxide and hydroxyl radical; and the oxidation of the cellular NADPH, the major source of reducing equivalents for the intracellular reduction of paraquat, which results in the disruption of important NADPH-requiring biochemical processes. The major cause of death in paraquat poisoning is respiratory failure due to an oxidative insult to the alveolar epithelium with subsequent obliterating fibrosis. Management of paraquat poisoning has remained mostly supportive and has been directed towards the modification of the toxicokinetics of the poison. Currently, there are no true pharmacological antagonists for paraquat and there are no chelating agents capable of binding the poison in the blood or other tissues. Recognizing the fact that paraquat induces its toxic effects via oxidative stress-mediated mechanisms, innovations in the management of paraquat poisoning are directed towards the use of antioxidants. In this review, the status of antioxidants in ameliorating or treating the toxic effects produced by paraquat is presented.", "title": "Role of antioxidants in paraquat toxicity." }, { "docid": "24097933", "text": "Paraquat poisoning is characterized by multiorgan failure and pulmonary fibrosis with respiratory failure. Multiorgan failure with circulatory collapse is a major cause of early death within 3 days of paraquat ingestion. Recent studies suggested that continuous venovenous hemofiltration (CVVH) had a role in the treatment of multiorgan failure by promoting hemodynamic stability. We therefore evaluated the effect of prophylactic CVVH in 80 patients with paraquat poisoning (August 1996 to February 1999). The amount ingested was 2.1 +/- 1.0 mouthfuls (as 20% concentrate). All patients were treated with hemoperfusion (HP; duration, 6.4 +/- 3.0 hours) within 24 hours of ingestion and then randomly assigned to the HP-alone or HP-CVVH group. Forty-four patients underwent HP only, and 36 patients underwent CVVH (duration, 57.4 +/- 31.3 hours; ultrafiltration volume, 40.2 +/- 4.8 L/d) after HP. Although time to death after ingestion was significantly longer in the HP-CVVH than HP group (5.0 +/- 5.0 versus 2.5 +/- 2.1 days; P < 0.05), there was no difference in mortality rates between the two groups (66.7% versus 63.6%; P = 0.82). In the HP group, early circulatory collapse was a major cause of death compared with the HP-CVVH group, in which late respiratory failure was a major cause of death. In conclusion, prophylactic CVVH after HP prevented early death caused by circulatory collapse and prolonged survival time. However, it could not prevent late death caused by respiratory failure and did not provide a survival benefit in acute paraquat poisoning.", "title": "Failure of continuous venovenous hemofiltration to prevent death in paraquat poisoning." }, { "docid": "41294031", "text": "BACKGROUND Paraquat is an effective and widely used herbicide but is also a lethal poison. In many developing countries paraquat is widely available and inexpensive, making poisoning prevention difficult. However most of the people who become poisoned from paraquat have taken it as a means of suicide. Standard treatment for paraquat poisoning both prevents further absorption and reduces the load of paraquat in the blood through haemoperfusion or haemodialysis. The effectiveness of standard treatments is extremely limited. The immune system plays an important role in exacerbating paraquat-induced lung fibrosis. Immunosuppressive treatment using glucocorticoid and cyclophosphamide in combination is being developed and studied. \n OBJECTIVES To assess the effects of glucocorticoid with cyclophosphamide on mortality in patients with paraquat-induced lung fibrosis. SEARCH METHODS To identify randomised controlled trials (RCTs) on this topic, we searched the Cochrane Injuries Group's Specialised Register (searched 1 February 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE (Ovid SP) (1946 January Week 3 2012), EMBASE (Ovid SP) (1947 to Week 4 2012), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) (1970 to January 2012), ISI Web of Science: Conference Proceedings Citation Index - Science (CPCI-S) (1990 to January 2012), Chinese Biomedical Literature and Retrieval System (CBM) (1978 to April 2012), Chinese Medical Current Contents (CMCC) (1995 to April 2012), and Chinese Medical Academic Conference (CMAC) (1994 to April 2012). Searches were completed on English language databases on 1 February 2012 and on Chinese language databases on 12 April 2012. SELECTION CRITERIA RCTs were included in this review. All patients were to receive standard care, plus the intervention or control. The intervention was glucocorticoid with cyclophosphamide in combination versus a control of a placebo, standard care alone or any other therapy in addition to standard care. \n DATA COLLECTION AND ANALYSIS The mortality risk ratio (RR) and 95% confidence interval (CI) was calculated for each study on an intention-to-treat basis. Data for all-cause mortality at final follow-up were summarised in a meta-analysis using a fixed-effect model. \n MAIN RESULTS This systematic review includes three trials with a combined total of 164 participants who had moderate to severe paraquat poisoning. Patients who received glucocorticoid with cyclophosphamide in addition to standard care had a lower risk of death at final follow-up than those receiving standard care only (RR 0.72; 95% CI 0.59 to 0.89). AUTHORS' CONCLUSIONS Based on the findings of three small RCTs of moderate to severely poisoned patients, glucocorticoid with cyclophosphamide in addition to standard care may be a beneficial treatment for patients with paraquat-induced lung fibrosis. To enable further study of the effects of glucocorticoid with cyclophosphamide for patients with moderate to severe paraquat poisoning, hospitals may provide this treatment as part of an RCT with allocation concealment.", "title": "Glucocorticoid with cyclophosphamide for paraquat-induced lung fibrosis." }, { "docid": "40005757", "text": "Serious exposure to the herbicide paraquat usually results in death, either due to gastrointestinal caustic lesions, shock, and acute respiratory distress syndrome or related to the progressive development of pulmonary fibrosis associated with refractory hypoxemia. We report a case of suicidal paraquat ingestion in a 59-year-old man. Most of the indicators of poor prognosis were encountered in this patient. Treatment consisted of early digestive decontamination and hemodialysis, followed by antioxidant therapy, including the administration of deferoxamine (100 mg/kg in 24 h) and a continuous infusion of acetylcysteine (300 mg/kg/d during 3 weeks). The patient only developed a nonoliguric acute renal failure, a mild alteration of liver tests, and an impairment of CO transfer factor without any respiratory complaint. Renal and hepatic disturbances completely resolved within 1 month, whereas CO transfer factor remained altered 14 months later. This observation suggests that early administration of an antioxidant therapy, including deferoxamine and acetylcysteine could be usefully associated with measures that prevent digestive absorption or enhance elimination to limit systemic toxicity in potentially fatal paraquat poisoning.", "title": "Survival in a case of massive paraquat ingestion." }, { "docid": "24525112", "text": "Paraquat intoxication is a fatal problem. Most paraquat intoxications happen through oral administration. We report a case of death after intravenous paraquat injection. There is little clinical data on parenteral paraquat exposure, and we describe this case and fatal progression. Toxic symptoms and severe organ function impairment developed soon after injection. Treatment with repeated activated charcoal hemoperfusion with pulse steroids, cyclophosphamide, and antioxidants was attempted. The patient died from multiple organ failure 3 days after intoxication. This case indicates that paraquat intoxication via intravenous injection, even in very small amounts, has an extremely poor prognosis.", "title": "A case of paraquat intoxication caused by intravenous injection." }, { "docid": "9976969", "text": "Psychiatric illness is a significant risk factor for both attempted and completed suicide and psychotropic medications account for 80% of all drug overdoses involving prescription medications. One challenge facing clinicians is to balance the benefit of treatment against the risk of drug overdose. The aim of the present study was to compare the age and gender distribution of patients prescribed psychotropic drugs with patients attempting and completing suicide with these drugs. Data were obtained from the Australian census and studies of general practitioner prescribing, patients who committed suicide or presented with self-poisoning within a defined geographic area. The characteristics of these populations were compared to calculate odds ratios for attempting or completing suicide with psychotropic drugs, before and after correction for rates of prescription, in different age and gender groups. The odds ratios (ORs) for self-poisoning were higher for those aged less than 45 years and yet this group was least likely to be prescribed psychotropic drugs. Men had a much higher rate of completed suicide using more lethal methods. The ORs for self-poisoning and suicide with psychotropic drugs, after correction for prescription rates, for those aged 15 to 24 years were 11.1 and 1.7, respectively. Those aged 25 to 44 years had ORs of 4.9 and 4.3, and, by contrast, those over 75 years had ORs of 0.03 and 0. Women were slightly more likely to poison themselves with psychotropic drugs (OR 1.2). However, the situation reversed after correction for prescription rates (OR 0.69). It is concluded that greater caution should be exercised in prescribing for those under 45 years of age, given their relatively higher risk of drug overdose, and that the least toxic compounds should be used. The risk (of self-poisoning) among the elderly may have been overstated, so that some patients may have been denied the benefit of adequate treatment.", "title": "An analysis of age and gender influences on the relative risk for suicide and psychotropic drug self-poisoning." }, { "docid": "12442311", "text": "BACKGROUND The analgesic co-proxamol (paracetamol/dextropropoxyphene combination) has been widely involved in fatal poisoning. Concerns about its safety/effectiveness profile and widespread use for suicidal poisoning prompted its withdrawal in the UK in 2005, with partial withdrawal between 2005 and 2007, and full withdrawal in 2008. Our objective in this study was to assess the association between co-proxamol withdrawal and prescribing and deaths in England and Wales in 2005-2010 compared with 1998-2004, including estimation of possible substitution effects by other analgesics. \n METHODS AND FINDINGS We obtained prescribing data from the NHS Health and Social Care Information Centre (England) and Prescribing Services Partneriaeth Cydwasanaethau GIG Cymru (Wales), and mortality data from the Office for National Statistics. We carried out an interrupted time-series analysis of prescribing and deaths (suicide, open verdicts, accidental poisonings) involving single analgesics. The reduction in prescribing of co-proxamol following its withdrawal in 2005 was accompanied by increases in prescribing of several other analgesics (co-codamol, paracetamol, codeine, co-dydramol, tramadol, oxycodone, and morphine) during 2005-2010 compared with 1998-2004. These changes were associated with major reductions in deaths due to poisoning with co-proxamol receiving verdicts of suicide and undetermined cause of -21 deaths (95% CI -34 to -8) per quarter, equating to approximately 500 fewer suicide deaths (-61%) over the 6 years 2005-2010, and -25 deaths (95% CI -38 to -12) per quarter, equating to 600 fewer deaths (-62%) when accidental poisoning deaths were included. There was little observed change in deaths involving other analgesics, apart from an increase in oxycodone poisonings, but numbers were small. Limitations were that the study was based on deaths involving single drugs alone and changes in deaths involving prescribed morphine could not be assessed. \n CONCLUSIONS During the 6 years following the withdrawal of co-proxamol in the UK, there was a major reduction in poisoning deaths involving this drug, without apparent significant increase in deaths involving other analgesics.", "title": "Six-Year Follow-Up of Impact of Co-proxamol Withdrawal in England and Wales on Prescribing and Deaths: Time-Series Study" }, { "docid": "46346525", "text": "Mu transposons carrying the chloramphenicol resistance marker have been inserted into the cloned Escherichia coli genes sodA and sodB coding for manganese superoxide dismutase (MnSOD) and iron superoxide dismutase (FeSOD) respectively, creating mutations and gene fusions. The mutated sodA or sodB genes were introduced into the bacterial chromosome by allelic exchange. The resulting mutants were shown to lack the corresponding SOD by activity measurements and immunoblot analysis. Aerobically, in rich medium, the absence of FeSOD or MnSOD had no major effect on growth or sensitivity to the superoxide generator, paraquat. In minimal medium aerobic growth was not affected, but the sensitivity to paraquat was increased, especially in the sodA mutant. A sodA sodB double mutant completely devoid of SOD was also obtained. It was able to grow aerobically in rich medium, its catalase level was unaffected and it was highly sensitive to paraquat and hydrogen peroxide; the double mutant was unable to grow aerobically on minimal glucose medium. Growth could be restored by removing oxygen, by providing an SOD-overproducing plasmid or by supplementing the medium with the 20 amino acids. It is concluded that the total absence of SOD in E. coli creates a conditional sensitivity to oxygen.", "title": "Isolation of superoxide dismutase mutants in Escherichia coli: is superoxide dismutase necessary for aerobic life?" }, { "docid": "32450297", "text": "THE herbicide paraquat (N,N′-dimethyl 4,4′-bipyridilium) can produce widespread oedema and fibrosis in the human lung after accidental ingestion1–3. In those cases where death occurs after several weeks, there are no apparent pulmonary changes during the first few days following ingestion. Animal experiments in a variety of species have shown the lung to be the major target organ4–6. After administration of paraquat to animals, the lung has a high initial concentration and retains paraquat7–9. This retention appears to be related to the development of lung damage7 (L. L. Smith and M. S. Rose, unpublished work). The mechanism of retention of paraquat by the lung is at present not understood.", "title": "Evidence for energy-dependent accumulation of paraquat into rat lung" }, { "docid": "13464392", "text": "OBJECTIVE Hypoproteinemia, fluid retention, and weight gain are associated with development of acute lung injury and mortality in critically ill patients, without proof of cause and effect. We designed a clinical trial to determine whether diuresis and colloid replacement in hypoproteinemic patients with acute lung injury would improve pulmonary physiology. \n DESIGN Prospective, randomized, double-blind, placebo-controlled trial. \n SETTING All adult intensive care units from two university hospitals. \n PATIENTS Thirty-seven mechanically-ventilated patients with acute lung injury and serum total protein </=5.0 g/dL. INTERVENTIONS Five-day protocolized regimen of 25 g of human serum albumin every 8 hrs with continuous infusion furosemide, or dual placebo, targeted to diuresis, weight loss, and serum total protein. \n MEASUREMENTS AND MAIN RESULTS Measured outcomes included change in weight, serum total protein, fluid balance, hemodynamics, respiratory system compliance, and oxygenation. Baseline characteristics were similar between groups (treatment, n = 19; control, n = 18), with trauma being the major cause of acute lung injury. Diuresis and weight loss over 5 days (5.3 kg more in the treatment group, p =.04) was accompanied by improvements in the Pao2/Fio2 ratio in the treatment group within 24 hrs (from 171 to 236, p =.02). Respiratory mechanics were unchanged. Mean arterial pressure increased from 80 to 88 mm Hg (p =.10), and heart rate decreased from 110 to 95 beats/min (p =.008) over time in the treatment group. No difference in mortality was observed, with favorable trends in measures of intensive care. \n CONCLUSIONS Albumin and furosemide therapy improves fluid balance, oxygenation, and hemodynamics in hypoproteinemic patients with acute lung injury. Determining the effect of this simple therapy on cost, outcomes, and other patient populations requires further study.", "title": "Albumin and furosemide therapy in hypoproteinemic patients with acute lung injury." }, { "docid": "13843341", "text": "OBJECTIVE To evaluate the cost effectiveness of standard treatment with and without the addition of ward based non-invasive ventilation in patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease. \n DESIGN Incremental cost effectiveness analysis of a randomised controlled trial. \n SETTING Medical wards in 14 hospitals in the United Kingdom. \n PARTICIPANTS The trial comprised 236 patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease and mild to moderate acidosis (pH 7.25-7.35) secondary to respiratory failure. The economic analysis compared the costs of treatment that these patients received after randomisation. \n MAIN OUTCOME MEASURE Incremental cost per in-hospital death. \n RESULTS 24/118 died in the group receiving standard treatment and 12/118 in the group receiving non-invasive ventilation (P=0.05). Allocation to the group receiving non-invasive ventilation was associated with a reduction in costs of 49362 pounds sterling (78741 dollars; 73109 euros), mainly through reduced use of intensive care units. The incremental cost effectiveness ratio was -645 pounds sterling per death avoided (95% confidence interval -2310 pounds sterling to 386 pounds sterling), indicating a dominant (more effective and less costly) strategy. Modelling of these data indicates that a typical UK hospital providing a non-invasive ventilation service will avoid six deaths and three to nine admissions to intensive care units per year, with an associated cost reduction of 12000-53000 pounds sterling per year. \n CONCLUSIONS Non-invasive ventilation is a highly cost effective treatment that both reduced total costs and improved mortality in hospital.", "title": "Cost effectiveness of ward based non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease: economic analysis of randomised controlled trial." }, { "docid": "471735", "text": "Escherichia coli responds to the redox stress imposed by superoxide-generating agents such as paraquat by activating the synthesis of as many as 80 polypeptides. Expression of a key group of these inducible proteins is controlled at the transcriptional level by the soxRS locus (the soxRS regulon). A two-stage control system was hypothesized for soxRS, in which an intracellular redox signal would trigger the SoxR protein as a transcriptional activator of the soxS gene and the resulting increased levels of SoxS protein would activate transcription of the various soxRS regulon genes (B. Demple and C.F. Amábile Cuevas, Cell 67:837-839, 1990). We have constructed operon fusions of the E. coli lac genes to the soxS promoter to monitor soxS transcription. Expression from the soxS promoter is strongly inducible by paraquat in a manner strictly dependent on a functional soxR gene. Several other superoxide-generating agents also trigger soxR(+)-dependent soxS expression, and the inductions by paraquat and phenazine methosulfate were dependent on the presence of oxygen. Numerous other oxidative stress agents (H2O2, gamma rays, heat shock, etc.) failed to induce soxS, while aerobic growth of superoxide dismutase-deficient bacteria triggered soxR-dependent soxS expression. These results indicate a specific redox signal for soxS induction. A direct role for SoxR protein in the activation of the soxS gene is indicated by band-shift and DNase I footprinting experiments that demonstrate specific binding of the SoxR protein in cell extracts to the soxS promoter. The mode of SoxR binding to DNA appears to be similar to that of its homolog MerR in that the SoxR footprint spans the -10 to -35 region of the soxS promoter.", "title": "Two-stage control of an oxidative stress regulon: the Escherichia coli SoxR protein triggers redox-inducible expression of the soxS regulatory gene." }, { "docid": "21884059", "text": "Graft-versus-host disease (GVHD) is a significant cause of morbidity and mortality following allogenic haematopoietic stem-cell transplantation and thus the focus of much ongoing research. Despite considerable advances in our understanding of the pathophysiology, diagnosis and predisposing factors for both acute and chronic forms of the disease, a standardised therapeutic strategy is still lacking. There is good evidence for initial treatment of both acute and chronic forms of the disease with corticosteroid therapy. However, the most effective approach to steroid-refractory disease remains controversial, with current practice based mainly on smaller studies and varying considerably between local institutions. Timely diagnosis, multidisciplinary working and good supportive care, including infection prophylaxis, are clearly important in optimizing response and survival in such patients. It is hoped that in the future systematic research strategies and the identification of novel therapeutic targets may improve outcome further. The following review aims to outline some of the existing options for the treatment and management of acute and chronic GVHD.", "title": "Treatment and management of graft-versus-host disease: improving response and survival." }, { "docid": "40156901", "text": "BACKGROUND Acute kidney injury (AKI) after cardiac surgery is associated with increased morbidity and mortality. \n METHODS We assessed whether statin treatment is associated with a lower incidence of postoperative AKI in 2,104 consecutive patients who underwent coronary artery bypass graft or valve surgery at the Minneapolis Veterans Administration Medical Center. Acute kidney injury was defined as absolute increase greater than 0.3 mg/dL or relative increase greater than 50% in serum creatinine from baseline, within 48 hours after surgery or requiring postoperative hemodialysis per AKI network. Propensity scores were utilized to adjust for the differences between the statin and the no-statin treatment groups. All statins were converted to equivalent-dose simvastatin and divided at the median to construct high-dose (≥40 mg) and low-dose (<40 mg) statin groups. \n RESULTS Of the 2,104 patients, 1,435 (68%) were taking statins (638 high-dose) and 495 (24%) developed AKI (25% high-dose vs 40% low-dose vs 35% no-statin; p = 0.014). Estimated preoperative glomerular filtration rate (p = 0.003), diabetes mellitus (p=0.02), valve surgery with or without coronary artery bypass graft (p = 0.024), cardiopulmonary bypass time (p = 0.001), and intraaortic balloon pump (p = 0.055) were independent predictors of AKI. After propensity adjustment statin treatment was not associated with postoperative AKI (odds ratio 0.79; 95% confidence interval 0.59 to 1.06; p = 0.11 for high-dose v. no-statin). After full adjustment for all independent predictors of AKI, the results did not change. Statins also had no effect on the incidence of postoperative hemodialysis (0.8% high-dose vs 1.9% low-dose vs 1% no-statin; p = 0.15). \n CONCLUSIONS Statin treatment is not associated with a lower incidence of AKI after cardiac surgery.", "title": "Dose-dependent effect of statins on the incidence of acute kidney injury after cardiac surgery." } ]

[ { "docid": "8447873", "text": "BACKGROUND Organophosphorus pesticide (OP) self-poisoning is a major problem in the developing rural world. There is little clinical trial data to guide therapy, hindering the identification of best therapy. Despite the recognition of adverse effects, gastric lavage is commonly done in Asia. We aimed to identify studies assessing its effectiveness. \n METHOD We systematically searched the literature for controlled clinical studies that assessed the effect of gastric lavage in OP pesticide self-poisoning. \n RESULTS All 56 studies identified were Chinese and reported benefit from the intervention studied, including multiple gastric lavages, use of norepinephrine or pralidoxime in the lavage fluid, concurrent treatment with naloxone or scopolamine, insertion of the gastric tube via a laparotomy incision, and lavage later than 12 h post-ingestion. However, only 23 were RCTs and none presented adequate methodology for their quality to be assessed. The patient population and study treatment protocol were not defined - large variation in case fatality in the control arm of the studies (from 4.5 to 93%) suggests marked variation between studies and likely between study arms. No study compared an intervention against a control group receiving no gastric lavage or provided any data to indicate whether a significant quantity of poison was removed. \n CONCLUSION Despite widespread use of multiple gastric lavages for OP pesticide poisoning across Asia, there is currently no high-quality evidence to support its clinical effectiveness. There is a need for studies to identify in which patients and for what duration gastric lavage is able to remove significant quantities of poison. Following these studies, large clinical trials will be required to address the effectiveness and safety of gastric lavage (either single or multiple) in acute OP pesticide poisoning.", "title": "Systematic review of controlled clinical trials of gastric lavage in acute organophosphorus pesticide poisoning." }, { "docid": "3430789", "text": "The present study retrospectively analyzed 19 patients diagnosed with paraquat (PQ) poisoning with the aim to investigate the effect of activated charcoal hemoperfusion on renal function and PQ elimination. The results indicated that 7 patients died and 12 survived. Non-oliguric renal failure occurred in all of the 7 patients who died. Among the 12 surviving patients, 10 had normal renal function and 2 developed non-oliguric renal failure. There was a linear correlation between plasma and urine paraquat concentration prior to and during activated charcoal hemoperfusion. The equation parameters together with the correlation coefficient on admission were as follows: Y=0.5820+1.7348X (R2=0.678; F=35.768; P<0.0001). The equation parameters together with the correlation coefficient were as follows during activated charcoal hemoperfusion: Y=0.6827+1.2649X (R2=0.626; F=50.308; P<0.0001). Therefore, it was concluded that in patients with normal renal function, the elimination kinetics of PQ by the kidneys were only associated with the plasma PQ concentration. Activated charcoal hemoperfusion had little effect on avoiding acute kidney injury in patients with severe PQ poisoning.", "title": "Effect of activated charcoal hemoperfusion on renal function in patients with paraquat poisoning." } ]

[ { "docid": "25104843", "text": "We report on a patient treated with hemoperfusion-hemodialysis (HP-HD) for severe paraquat poisoning. This procedure was adopted since the combination of adsorption and dialysis may improve overall drug removal. On admission blood paraquat was 15.8 micrograms/ml. He received conventional treatment and combined HP-HD which started within 3 hours after ingestion of the chemical and lasted 5 hours. Blood samples were obtained during and after HP-HD. The samples during HP-HD were taken before the charcoal column, between the charcoal column and the artificial kidney and after the artificial kidney. Blood clearances of paraquat were 116 +/- 32 ml/min (n=6) for the charcoal column (HP), 90 +/- 54 ml/min (n=6) for the artificial kidney (HD) and 151 +/- 37 ml/min (n=6) for the combined systems (HP-HD). After HP-HD a limited rebound of blood paraquat level was seen. One day after admission renal and hepatic failure had developed, and the patient died after 5 days. Tissue paraquat levels (microgram/g wet tissue) were: skeletal muscle 9.4, pancreas 6.0, prostate 5.6, thyroid 4.2, lungs 4.0, bone marrow 4.0, kidney 3.1, spleen 2.9, adrenal 2.9, heart 2.8, liver 2.3, stomach and testis below 1.0. Measurements of blood levels demonstrated the efficient clearances of paraquat with HP-HD from the central (plasma) compartment. However, the present results confirmed those previously reported which suggest that the efficiency of short HP-HD in treating severe paraquat poisoning is questionable since paraquat levels in the peripheral (tissue) compartment remain elevated.", "title": "Hemoperfusion-hemodialysis ineffective for paraquat removal in life-threatening poisoning?" }, { "docid": "12209494", "text": "BACKGROUND The case-fatality for intentional self-poisoning in the rural developing world is 10-50-fold higher than that in industrialised countries, mostly because of the use of highly toxic pesticides and plants. We therefore aimed to assess whether routine treatment with multiple-dose activated charcoal, to interrupt enterovascular or enterohepatic circulations, offers benefit compared with no charcoal in such an environment. \n METHODS We did an open-label, parallel group, randomised, controlled trial of six 50 g doses of activated charcoal at 4-h intervals versus no charcoal versus one 50 g dose of activated charcoal in three Sri Lankan hospitals. 4632 patients were randomised to receive no charcoal (n=1554), one dose of charcoal (n=1545), or six doses of charcoal (n=1533); outcomes were available for 4629 patients. 2338 (51%) individuals had ingested pesticides, whereas 1647 (36%) had ingested yellow oleander (Thevetia peruviana) seeds. Mortality was the primary outcome measure. Analysis was by intention to treat. The trial is registered with controlled-trials.com as ISRCTN02920054. \n FINDINGS Mortality did not differ between the groups. 97 (6.3%) of 1531 participants in the multiple-dose group died, compared with 105 (6.8%) of 1554 in the no charcoal group (adjusted odds ratio 0.96, 95% CI 0.70-1.33). No differences were noted for patients who took particular poisons, were severely ill on admission, or who presented early. \n INTERPRETATION We cannot recommend the routine use of multiple-dose activated charcoal in rural Asia Pacific; although further studies of early charcoal administration might be useful, effective affordable treatments are urgently needed.", "title": "Multiple-dose activated charcoal in acute self-poisoning: a randomised controlled trial" }, { "docid": "22547508", "text": "Acute paraquat poisoning is often fatal. Many studies have investigated successful treatment modalities, but no standard treatment yet exists. The purpose of this study was to determine the predictors of survival after acute paraquat poisoning in 602 patients. The paraquat exposure was assessed based on the amount of ingested paraquat and a semiquantitative measure of the urine level of paraquat. Initial clinical parameters including vital signs, hemoglobin, white-blood-cell count, pH, PaCO2, PaO2, blood urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, total bilirubin, amylase, and glucose were obtained at the time of arrival at the emergency room. Outcomes after acute paraquat poisoning were categorized as survivors and nonsurvivors. Multiple logistic regression analysis was applied to assess the predictors of survival after acute paraquat poisoning. Some patients (55.5%) survived after oral ingestion of paraquat, whereas all those exposed to paraquat percutaneous or inhalational route survived. The amount of paraquat (24.5% concentrate of 1,1'-dimethyl-4,4'-bipyridium dichloride) ingested was 45.6 +/- 74.1 mL (mean +/- SD). In addition to degree of paraquat exposure, survival after acute paraquat poisoning was associated with age, respiratory rate, pH, PaCO2, hemoglobin, white-blood-cell count, blood urea nitrogen, amylase, and the number of failed organs in multiple logistic regression analysis. In conclusion, young age, percutaneous or inhalational route, exposure to less paraquat, and lesser degrees of leukocytosis, acidosis, and renal, hepatic, and pancreatic failures on admission are good prognostic factors of survival after acute paraquat poisoning.", "title": "Predictors of survival after acute paraquat poisoning." }, { "docid": "24097933", "text": "Paraquat poisoning is characterized by multiorgan failure and pulmonary fibrosis with respiratory failure. Multiorgan failure with circulatory collapse is a major cause of early death within 3 days of paraquat ingestion. Recent studies suggested that continuous venovenous hemofiltration (CVVH) had a role in the treatment of multiorgan failure by promoting hemodynamic stability. We therefore evaluated the effect of prophylactic CVVH in 80 patients with paraquat poisoning (August 1996 to February 1999). The amount ingested was 2.1 +/- 1.0 mouthfuls (as 20% concentrate). All patients were treated with hemoperfusion (HP; duration, 6.4 +/- 3.0 hours) within 24 hours of ingestion and then randomly assigned to the HP-alone or HP-CVVH group. Forty-four patients underwent HP only, and 36 patients underwent CVVH (duration, 57.4 +/- 31.3 hours; ultrafiltration volume, 40.2 +/- 4.8 L/d) after HP. Although time to death after ingestion was significantly longer in the HP-CVVH than HP group (5.0 +/- 5.0 versus 2.5 +/- 2.1 days; P < 0.05), there was no difference in mortality rates between the two groups (66.7% versus 63.6%; P = 0.82). In the HP group, early circulatory collapse was a major cause of death compared with the HP-CVVH group, in which late respiratory failure was a major cause of death. In conclusion, prophylactic CVVH after HP prevented early death caused by circulatory collapse and prolonged survival time. However, it could not prevent late death caused by respiratory failure and did not provide a survival benefit in acute paraquat poisoning.", "title": "Failure of continuous venovenous hemofiltration to prevent death in paraquat poisoning." }, { "docid": "19132741", "text": "Paraquat, a quarternary nitrogen herbicide, is a highly toxic compound for humans and animals and many cases of acute poisoning and death have been reported over the past few decades. The mechanisms of paraquat toxicity involve: the generation of the superoxide anion, which can lead to the formation of more toxic reactive oxygen species, such as hydrogen peroxide and hydroxyl radical; and the oxidation of the cellular NADPH, the major source of reducing equivalents for the intracellular reduction of paraquat, which results in the disruption of important NADPH-requiring biochemical processes. The major cause of death in paraquat poisoning is respiratory failure due to an oxidative insult to the alveolar epithelium with subsequent obliterating fibrosis. Management of paraquat poisoning has remained mostly supportive and has been directed towards the modification of the toxicokinetics of the poison. Currently, there are no true pharmacological antagonists for paraquat and there are no chelating agents capable of binding the poison in the blood or other tissues. Recognizing the fact that paraquat induces its toxic effects via oxidative stress-mediated mechanisms, innovations in the management of paraquat poisoning are directed towards the use of antioxidants. In this review, the status of antioxidants in ameliorating or treating the toxic effects produced by paraquat is presented.", "title": "Role of antioxidants in paraquat toxicity." }, { "docid": "33203108", "text": "INTRODUCTION Paraquat is a commonly ingested poison especially in Southern India. There is no antidote for paraquat poison and consumption is often fatal. The usual cause of death is either acute lung injury or multi-organ failure. AIM To evaluate the role of early haemoperfusion as a therapy in paraquat poisoned patients. MATERIALS AND METHODS This study was a retrospective analysis of patients admitted to a Tertiary Medical College Hospital between January 2012 and December 2015 with history of paraquat consumption, comparing outcomes in those who received only gastric lavage and symptomatic treatment with those who received haemoperfusion as a therapy. The role of early haemoperfusion (≤ 6 hours) vs late haemoperfusion (> 6 hours) in paraquat poisoned patients was also compared. The data of these patients was extracted and analysed with respect to age, sex, mode of treatment, the outcome in patients who received early and late haemoperfusion. \n RESULTS A total of 101 patients were studied out of which 62 died. Deaths were more in those patients who received only gastric lavage with symptomatic treatment as therapy compared to those who received haemoperfusion i.e., 92.1% vs 42.9% respectively. We also found that, the survival rate was better in patients who received early haemoperfusion. \n CONCLUSION Early haemoperfusion was helpful in the management of severe paraquat poisoning and improved the survival rate in these patients.", "title": "Golden Hours in Severe Paraquat Poisoning-The Role of Early Haemoperfusion Therapy." }, { "docid": "40005757", "text": "Serious exposure to the herbicide paraquat usually results in death, either due to gastrointestinal caustic lesions, shock, and acute respiratory distress syndrome or related to the progressive development of pulmonary fibrosis associated with refractory hypoxemia. We report a case of suicidal paraquat ingestion in a 59-year-old man. Most of the indicators of poor prognosis were encountered in this patient. Treatment consisted of early digestive decontamination and hemodialysis, followed by antioxidant therapy, including the administration of deferoxamine (100 mg/kg in 24 h) and a continuous infusion of acetylcysteine (300 mg/kg/d during 3 weeks). The patient only developed a nonoliguric acute renal failure, a mild alteration of liver tests, and an impairment of CO transfer factor without any respiratory complaint. Renal and hepatic disturbances completely resolved within 1 month, whereas CO transfer factor remained altered 14 months later. This observation suggests that early administration of an antioxidant therapy, including deferoxamine and acetylcysteine could be usefully associated with measures that prevent digestive absorption or enhance elimination to limit systemic toxicity in potentially fatal paraquat poisoning.", "title": "Survival in a case of massive paraquat ingestion." }, { "docid": "41294031", "text": "BACKGROUND Paraquat is an effective and widely used herbicide but is also a lethal poison. In many developing countries paraquat is widely available and inexpensive, making poisoning prevention difficult. However most of the people who become poisoned from paraquat have taken it as a means of suicide. Standard treatment for paraquat poisoning both prevents further absorption and reduces the load of paraquat in the blood through haemoperfusion or haemodialysis. The effectiveness of standard treatments is extremely limited. The immune system plays an important role in exacerbating paraquat-induced lung fibrosis. Immunosuppressive treatment using glucocorticoid and cyclophosphamide in combination is being developed and studied. \n OBJECTIVES To assess the effects of glucocorticoid with cyclophosphamide on mortality in patients with paraquat-induced lung fibrosis. SEARCH METHODS To identify randomised controlled trials (RCTs) on this topic, we searched the Cochrane Injuries Group's Specialised Register (searched 1 February 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE (Ovid SP) (1946 January Week 3 2012), EMBASE (Ovid SP) (1947 to Week 4 2012), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) (1970 to January 2012), ISI Web of Science: Conference Proceedings Citation Index - Science (CPCI-S) (1990 to January 2012), Chinese Biomedical Literature and Retrieval System (CBM) (1978 to April 2012), Chinese Medical Current Contents (CMCC) (1995 to April 2012), and Chinese Medical Academic Conference (CMAC) (1994 to April 2012). Searches were completed on English language databases on 1 February 2012 and on Chinese language databases on 12 April 2012. SELECTION CRITERIA RCTs were included in this review. All patients were to receive standard care, plus the intervention or control. The intervention was glucocorticoid with cyclophosphamide in combination versus a control of a placebo, standard care alone or any other therapy in addition to standard care. \n DATA COLLECTION AND ANALYSIS The mortality risk ratio (RR) and 95% confidence interval (CI) was calculated for each study on an intention-to-treat basis. Data for all-cause mortality at final follow-up were summarised in a meta-analysis using a fixed-effect model. \n MAIN RESULTS This systematic review includes three trials with a combined total of 164 participants who had moderate to severe paraquat poisoning. Patients who received glucocorticoid with cyclophosphamide in addition to standard care had a lower risk of death at final follow-up than those receiving standard care only (RR 0.72; 95% CI 0.59 to 0.89). AUTHORS' CONCLUSIONS Based on the findings of three small RCTs of moderate to severely poisoned patients, glucocorticoid with cyclophosphamide in addition to standard care may be a beneficial treatment for patients with paraquat-induced lung fibrosis. To enable further study of the effects of glucocorticoid with cyclophosphamide for patients with moderate to severe paraquat poisoning, hospitals may provide this treatment as part of an RCT with allocation concealment.", "title": "Glucocorticoid with cyclophosphamide for paraquat-induced lung fibrosis." }, { "docid": "24525112", "text": "Paraquat intoxication is a fatal problem. Most paraquat intoxications happen through oral administration. We report a case of death after intravenous paraquat injection. There is little clinical data on parenteral paraquat exposure, and we describe this case and fatal progression. Toxic symptoms and severe organ function impairment developed soon after injection. Treatment with repeated activated charcoal hemoperfusion with pulse steroids, cyclophosphamide, and antioxidants was attempted. The patient died from multiple organ failure 3 days after intoxication. This case indicates that paraquat intoxication via intravenous injection, even in very small amounts, has an extremely poor prognosis.", "title": "A case of paraquat intoxication caused by intravenous injection." }, { "docid": "9976969", "text": "Psychiatric illness is a significant risk factor for both attempted and completed suicide and psychotropic medications account for 80% of all drug overdoses involving prescription medications. One challenge facing clinicians is to balance the benefit of treatment against the risk of drug overdose. The aim of the present study was to compare the age and gender distribution of patients prescribed psychotropic drugs with patients attempting and completing suicide with these drugs. Data were obtained from the Australian census and studies of general practitioner prescribing, patients who committed suicide or presented with self-poisoning within a defined geographic area. The characteristics of these populations were compared to calculate odds ratios for attempting or completing suicide with psychotropic drugs, before and after correction for rates of prescription, in different age and gender groups. The odds ratios (ORs) for self-poisoning were higher for those aged less than 45 years and yet this group was least likely to be prescribed psychotropic drugs. Men had a much higher rate of completed suicide using more lethal methods. The ORs for self-poisoning and suicide with psychotropic drugs, after correction for prescription rates, for those aged 15 to 24 years were 11.1 and 1.7, respectively. Those aged 25 to 44 years had ORs of 4.9 and 4.3, and, by contrast, those over 75 years had ORs of 0.03 and 0. Women were slightly more likely to poison themselves with psychotropic drugs (OR 1.2). However, the situation reversed after correction for prescription rates (OR 0.69). It is concluded that greater caution should be exercised in prescribing for those under 45 years of age, given their relatively higher risk of drug overdose, and that the least toxic compounds should be used. The risk (of self-poisoning) among the elderly may have been overstated, so that some patients may have been denied the benefit of adequate treatment.", "title": "An analysis of age and gender influences on the relative risk for suicide and psychotropic drug self-poisoning." }, { "docid": "80109277", "text": "© Joanna Moncrieff 2013. All rights reserved. A challenging reappraisal of the history of antipsychotics, revealing how they were transformed from neurological poisons into magical cures, their benefits exaggerated and their toxic effects minimized or ignored.", "title": "The Bitterest Pills: The Troubling Story of Antipsychotic Drugs" }, { "docid": "32450297", "text": "THE herbicide paraquat (N,N′-dimethyl 4,4′-bipyridilium) can produce widespread oedema and fibrosis in the human lung after accidental ingestion1–3. In those cases where death occurs after several weeks, there are no apparent pulmonary changes during the first few days following ingestion. Animal experiments in a variety of species have shown the lung to be the major target organ4–6. After administration of paraquat to animals, the lung has a high initial concentration and retains paraquat7–9. This retention appears to be related to the development of lung damage7 (L. L. Smith and M. S. Rose, unpublished work). The mechanism of retention of paraquat by the lung is at present not understood.", "title": "Evidence for energy-dependent accumulation of paraquat into rat lung" }, { "docid": "14361849", "text": "IntroductionWe conducted the present study to investigate the potential beneficial and adverse effects of continuous positive airway pressure (CPAP) compared with bi-level positive airway pressure (BiPAP) noninvasive ventilation in patients with cardiogenic pulmonary oedema. MethodWe included randomized controlled studies comparing CPAP and BiPAP treatment in patients with cardiogenic pulmonary oedema from the Cochrane Controlled Trials Register (2005 issue 3), and EMBASE and MEDLINE databases (1966 to 1 December 2005), without language restriction. Two reviewers reviewed the quality of the studies and independently performed data extraction. ResultsSeven randomized controlled studies, including a total of 290 patients with cardiogenic pulmonary oedema, were considered. The hospital mortality (relative risk [RR] 0.76, 95% confidence interval [CI] 0.32–1.78; P = 0.52; I2 = 0%) and risk for requiring invasive ventilation (RR 0.80, 95% CI 0.33–1.94; P = 0.62; I2 = 0%) were not significantly different between patients treated with CPAP and those treated with BiPAP. Stratifying studies that used either fixed or titrated pressure during BiPAP treatment and studies involving patients with or without hypercapnia did not change the results. The duration of noninvasive ventilation required until the pulmonary oedema resolved (weighted mean difference [WMD] in hours = 3.65, 95% CI -12.12 to +19.43; P = 0.65, I2 = 0%) and length of hospital stay (WMD in days = -0.04, 95% CI -2.57 to +2.48; P = 0.97, I2 = 0%) were also not significantly different between the two groups. Based on the limited data available, there was an insignificant trend toward an increase in new onset acute myocardial infarction in patients treated with BiPAP (RR 2.10, 95% CI 0.91–4.84; P = 0.08; I2 = 25.3%).ConclusionBiPAP does not offer any significant clinical benefits over CPAP in patients with acute cardiogenic pulmonary oedema. Until a large randomized controlled trial shows significant clinical benefit and cost-effectiveness of BiPAP versus CPAP in patients with acute cardiogenic pulmonary oedema, the choice of modality will depend mainly on the equipment available.", "title": "A comparison of continuous and bi-level positive airway pressure non-invasive ventilation in patients with acute cardiogenic pulmonary oedema: a meta-analysis" }, { "docid": "7873737", "text": "BACKGROUND Diabetes mellitus is a major risk factor for adverse outcomes after acute coronary syndromes (ACS). Because this disease may be associated with increased platelet aggregation, we investigated whether diabetic patients with ACS derive particular benefit from platelet glycoprotein (GP) IIb/IIIa receptor inhibition. \n METHODS AND RESULTS We performed a meta-analysis of the diabetic populations enrolled in the 6 large-scale platelet GP IIb/IIIa inhibitor ACS trials: PRISM, PRISM-PLUS, PARAGON A, PARAGON B, PURSUIT, and GUSTO IV. Among 6458 diabetic patients, platelet GP IIb/IIIa inhibition was associated with a significant mortality reduction at 30 days, from 6.2% to 4.6% (OR 0.74; 95% CI 0.59 to 0.92; P=0.007). Conversely, 23 072 nondiabetic patients had no survival benefit (3.0% versus 3.0%). The interaction between platelet GP IIb/IIIa inhibition and diabetic status was statistically significant (P=0.036). Among 1279 diabetic patients undergoing percutaneous coronary intervention (PCI) during index hospitalization, the use of these agents was associated with a mortality reduction at 30 days from 4.0% to 1.2% (OR 0.30; 95% CI 0.14 to 0.69; P=0.002). \n CONCLUSIONS This meta-analysis, including the entire large-scale trial experience of intravenous platelet GP IIb/IIIa inhibitors for the medical management of non-ST-segment-elevation ACS, shows that these agents may significantly reduce mortality at 30 days in diabetic patients. Although not based on a randomized assessment, the survival benefit appears to be of greater magnitude in patients undergoing PCI. Therefore, the use of platelet GP IIb/IIIa inhibitors should be strongly considered in diabetic patients with ACS.", "title": "Platelet glycoprotein IIb/IIIa inhibitors reduce mortality in diabetic patients with non-ST-segment-elevation acute coronary syndromes." }, { "docid": "12442311", "text": "BACKGROUND The analgesic co-proxamol (paracetamol/dextropropoxyphene combination) has been widely involved in fatal poisoning. Concerns about its safety/effectiveness profile and widespread use for suicidal poisoning prompted its withdrawal in the UK in 2005, with partial withdrawal between 2005 and 2007, and full withdrawal in 2008. Our objective in this study was to assess the association between co-proxamol withdrawal and prescribing and deaths in England and Wales in 2005-2010 compared with 1998-2004, including estimation of possible substitution effects by other analgesics. \n METHODS AND FINDINGS We obtained prescribing data from the NHS Health and Social Care Information Centre (England) and Prescribing Services Partneriaeth Cydwasanaethau GIG Cymru (Wales), and mortality data from the Office for National Statistics. We carried out an interrupted time-series analysis of prescribing and deaths (suicide, open verdicts, accidental poisonings) involving single analgesics. The reduction in prescribing of co-proxamol following its withdrawal in 2005 was accompanied by increases in prescribing of several other analgesics (co-codamol, paracetamol, codeine, co-dydramol, tramadol, oxycodone, and morphine) during 2005-2010 compared with 1998-2004. These changes were associated with major reductions in deaths due to poisoning with co-proxamol receiving verdicts of suicide and undetermined cause of -21 deaths (95% CI -34 to -8) per quarter, equating to approximately 500 fewer suicide deaths (-61%) over the 6 years 2005-2010, and -25 deaths (95% CI -38 to -12) per quarter, equating to 600 fewer deaths (-62%) when accidental poisoning deaths were included. There was little observed change in deaths involving other analgesics, apart from an increase in oxycodone poisonings, but numbers were small. Limitations were that the study was based on deaths involving single drugs alone and changes in deaths involving prescribed morphine could not be assessed. \n CONCLUSIONS During the 6 years following the withdrawal of co-proxamol in the UK, there was a major reduction in poisoning deaths involving this drug, without apparent significant increase in deaths involving other analgesics.", "title": "Six-Year Follow-Up of Impact of Co-proxamol Withdrawal in England and Wales on Prescribing and Deaths: Time-Series Study" }, { "docid": "29526125", "text": "BACKGROUND A major challenge for physicians is to identify patients with acute coronary syndromes who may benefit from treatment with glycoprotein-IIb/IIIa-receptor antagonists. We investigated whether troponin concentrations can be used to stratify patients for benefit from treatment with tirofiban. \n METHODS We enrolled 2222 patients of the Platelet Receptor Inhibition in Ischemic Syndrome Management study with coronary artery disease and who had had chest pain in the previous 24 h. All patients received aspirin and were randomly assigned treatment with tirofiban or heparin. We took baseline measurements of troponin I and troponin T. We recorded death, myocardial infarction, or recurrent ischaemia after 48 h infusion treatment and at 7 days and 30 days. \n FINDINGS 629 (28.3%) patients had troponin I concentrations higher than the diagnostic threshold of 1.0 microg/L and 644 (29.0%) troponin T concentrations higher than 0.1 microg/L. 30-day event rates (death, myocardial infarction) were 13.0% for troponin-I-positive patients compared with 4.9% for troponin-I-negative patients (p<0.0001), and 13.7% compared wth 3.5% for troponin T (p<0.001). At 30 days, in troponin-I-positive patients, tirofiban had lowered the risk of death (adjusted hazard ratio 0.25 [95% CI 0.09-0.68], p=0.004) and myocardial infarction (0.37 [0.16-0.84], p=0.01). This benefit was seen in medically managed patients (0.30 [0.10-0.84], p=0.004) and those undergoing revascularisation (0.37 [0.15-0.93] p=0.02) after 48 h infusion treatment. By contrast, no treatment effect was seen for troponin-I-negative patients. Similar benefits were seen for troponin-T-positive patients. \n INTERPRETATION Troponin I and troponin T reliably identified high-risk patients with acute coronary syndromes, managed medically and by revascularisation, who would benefit from tirofiban.", "title": "Troponin concentrations for stratification of patients with acute coronary syndromes in relation to therapeutic efficacy of tirofiban. PRISM Study Investigators. Platelet Receptor Inhibition in Ischemic Syndrome Management." }, { "docid": "46346525", "text": "Mu transposons carrying the chloramphenicol resistance marker have been inserted into the cloned Escherichia coli genes sodA and sodB coding for manganese superoxide dismutase (MnSOD) and iron superoxide dismutase (FeSOD) respectively, creating mutations and gene fusions. The mutated sodA or sodB genes were introduced into the bacterial chromosome by allelic exchange. The resulting mutants were shown to lack the corresponding SOD by activity measurements and immunoblot analysis. Aerobically, in rich medium, the absence of FeSOD or MnSOD had no major effect on growth or sensitivity to the superoxide generator, paraquat. In minimal medium aerobic growth was not affected, but the sensitivity to paraquat was increased, especially in the sodA mutant. A sodA sodB double mutant completely devoid of SOD was also obtained. It was able to grow aerobically in rich medium, its catalase level was unaffected and it was highly sensitive to paraquat and hydrogen peroxide; the double mutant was unable to grow aerobically on minimal glucose medium. Growth could be restored by removing oxygen, by providing an SOD-overproducing plasmid or by supplementing the medium with the 20 amino acids. It is concluded that the total absence of SOD in E. coli creates a conditional sensitivity to oxygen.", "title": "Isolation of superoxide dismutase mutants in Escherichia coli: is superoxide dismutase necessary for aerobic life?" }, { "docid": "6158879", "text": "BACKGROUND Patients with diabetes mellitus (DM) are at high risk for recurrent cardiovascular events after acute coronary syndromes, in part because of increased platelet reactivity. The Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction 38 (TRITON-TIMI 38) showed an overall reduction in ischemic events with more intensive antiplatelet therapy with prasugrel than with clopidogrel but with more bleeding. We compared prasugrel with clopidogrel among subjects with DM in TRITON-TIMI 38. \n METHODS AND RESULTS We classified 13 608 subjects on the basis of preexisting history of DM and further according to insulin use. Prespecified analyses of the primary (cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke) and key secondary end points, including net clinical benefit (death, nonfatal myocardial infarction, nonfatal stroke, and nonfatal TIMI major bleeding) were compared by use of the log-rank test. We found that 3146 subjects had a preexisting history of DM, including 776 receiving insulin. The primary end point was reduced significantly with prasugrel among subjects without DM (9.2% versus 10.6%; hazard ratio [HR], 0.86; P=0.02) and with DM (12.2% versus 17.0%; HR, 0.70; P<0.001, P(interaction)=0.09). A benefit for prasugrel was observed among DM subjects on insulin (14.3% versus 22.2%; HR, 0.63; P=0.009) and those not on insulin (11.5% versus 15.3%; HR, 0.74; P=0.009). Myocardial infarction was reduced with prasugrel by 18% among subjects without DM (7.2% versus 8.7%; HR, 0.82; P=0.006) and by 40% among subjects with DM (8.2% versus 13.2%; HR, 0.60; P<0.001, P(interaction)=0.02). Although TIMI major hemorrhage was increased among subjects without DM on prasugrel (1.6% versus 2.4%; HR, 1.43; P=0.02), the rates were similar among subjects with DM for clopidogrel and prasugrel (2.6% versus 2.5%; HR, 1.06; P=0.81, P(interaction)=0.29). Net clinical benefit with prasugrel was greater for subjects with DM (14.6% versus 19.2%; HR, 0.74; P=0.001) than for subjects without DM (11.5% versus 12.3%; HR, 0.92; P=0.16, P(interaction)=0.05). \n CONCLUSIONS Subjects with DM tended to have a greater reduction in ischemic events without an observed increase in TIMI major bleeding and therefore a greater net treatment benefit with prasugrel compared with clopidogrel. These data demonstrate that the more intensive oral antiplatelet therapy provided with prasugrel is of particular benefit to patients with DM.", "title": "Greater clinical benefit of more intensive oral antiplatelet therapy with prasugrel in patients with diabetes mellitus in the trial to assess improvement in therapeutic outcomes by optimizing platelet inhibition with prasugrel-Thrombolysis in Myocardial Infarction 38." } ]

[ { "docid": "13578199", "text": "Human transglutaminase 2 (TG2), a member of a large family of enzymes that catalyze protein crosslinking, plays an important role in the extracellular matrix biology of many tissues and is implicated in the gluten-induced pathogenesis of celiac sprue. Although vertebrate transglutaminases have been studied extensively, thus far all structurally characterized members of this family have been crystallized in conformations with inaccessible active sites. We have trapped human TG2 in complex with an inhibitor that mimics inflammatory gluten peptide substrates and have solved, at 2-A resolution, its x-ray crystal structure. The inhibitor stabilizes TG2 in an extended conformation that is dramatically different from earlier transglutaminase structures. The active site is exposed, revealing that catalysis takes place in a tunnel, bridged by two tryptophan residues that separate acyl-donor from acyl-acceptor and stabilize the tetrahedral reaction intermediates. Site-directed mutagenesis was used to investigate the acyl-acceptor side of the tunnel, yielding mutants with a marked increase in preference for hydrolysis over transamidation. By providing the ability to visualize this activated conformer, our results create a foundation for understanding the catalytic as well as the non-catalytic roles of TG2 in biology, and for dissecting the process by which the autoantibody response to TG2 is induced in celiac sprue patients.", "title": "Transglutaminase 2 Undergoes a Large Conformational Change upon Activation " } ]

[ { "docid": "10474873", "text": "Failure of axons of the central nervous system in adult mammals to regenerate spontaneously after injury is attributed in part to inhibitory molecules associated with oligodendrocytes. Regeneration of central nervous system axons in fish is correlated with the presence of a transglutaminase. This enzyme dimerizes interleukin-2, and the product is cytotoxic to oligodendrocytes in vitro. Application of this nerve-derived transglutaminase to rat optic nerves, in which the injury had caused the loss of visual evoked potential response to light, promoted the recovery of that response within 6 weeks after injury. Transmission electron microscopy analysis revealed the concomitant appearance of axons in the distal stump of the optic nerve.", "title": "Recovery of visual response of injured adult rat optic nerves treated with transglutaminase." }, { "docid": "26008462", "text": "Repair of tissue after injury depends on a series of concerted but overlapping events including, inflammation, re-epithelialization, neovascularization and synthesis and stabilization of a fibrous extracellular matrix (ECM) that is remodeled to emulate normal tissue over time. Particular members of the transglutaminase (TG) family are upregulated during wound healing and act as a novel class of wound-healing mediators during the repair process. This group of enzymes which crosslink proteins via epsilon(gamma-glutamyl) lysine bridges are involved in wound healing through their ability to stabilize proteins and also by regulating the behavior of a wide variety of cell types that are recruited to the damaged area in order to carry out tissue repair. In this article we discuss the function of the most widely expressed member of the TG family \"tissue transglutaminase\" (TG2) in wound repair. Using both early and recent evidence from the literature we demonstrate how the multifunctional TG2 affects the stability of the ECM, cell-ECM interactions and as a consequence cell behavior within the different phases of wound healing, and highlight how TG2 itself might be exploited for therapeutic use.", "title": "Tissue transglutaminase (TG2)--a wound response enzyme." }, { "docid": "10669582", "text": "The protein cross-linking enzyme tissue transglutaminase binds in vitro with high affinity to fibronectin via its 42-kD gelatin-binding domain. Here we report that cell surface transglutaminase mediates adhesion and spreading of cells on the 42-kD fibronectin fragment, which lacks integrin-binding motifs. Overexpression of tissue transglutaminase increases its amount on the cell surface, enhances adhesion and spreading on fibronectin and its 42-kD fragment, enlarges focal adhesions, and amplifies adhesion-dependent phosphorylation of focal adhesion kinase. These effects are specific for tissue transglutaminase and are not shared by its functional homologue, a catalytic subunit of factor XIII. Adhesive function of tissue transglutaminase does not require its cross-linking activity but depends on its stable noncovalent association with integrins. Transglutaminase interacts directly with multiple integrins of β1 and β3 subfamilies, but not with β2 integrins. Complexes of transglutaminase with integrins are formed inside the cell during biosynthesis and accumulate on the surface and in focal adhesions. Together our results demonstrate that tissue transglutaminase mediates the interaction of integrins with fibronectin, thereby acting as an integrin-associated coreceptor to promote cell adhesion and spreading.", "title": "Tissue Transglutaminase Is an Integrin-Binding Adhesion Coreceptor for Fibronectin" }, { "docid": "24346598", "text": "PURPOSE To assess the efficacy, dose stability, safety, and abuse potential of long-term, nightly benzodiazepine treatment of chronic disorders of disrupted nocturnal sleep. \n PATIENTS AND METHODS During a 12-year period, one author evaluated and treated 170 adult referrals for > or = 6 months with nightly benzodiazepine therapy for longstanding, sleep-disruptive disorders: injurious sleepwalking and sleep terrors (69); rapid eye movement sleep behavior disorder (52); chronic, severe insomnia (25); and restless legs syndrome/periodic limb movement disorder (24). \n RESULTS Complete/substantial control of the sleep disorders was achieved by 146 patients (86%); 8% had adverse effects requiring medication changes; 2% had relapses of alcohol or chemical abuse requiring hospitalization; another 2% at times misused their medications. A total of 136 patients received clonazepam nightly for a mean 3.5 (+/- 2.4) years, with no significant difference in inital versus final mean dose: 0.77 mg (+/- 0.46) versus 1.10 mg (+/- 0.96). Similar results were obtained with chronic alprazolam treatment and with other benzodiazepine treatments. \n CONCLUSION Long-term, nightly benzodiazepine treatment of injurious parasomnias and other disorders of disrupted nocturnal sleep resulted in sustained efficacy in most cases, with low risk of dosage tolerance, adverse effects, or abuse. Data from this study on the treatment of chronic, severe insomnia (a small subset of all insomnia) are not generalizable to the typical insomnia patient.", "title": "Long-term, nightly benzodiazepine treatment of injurious parasomnias and other disorders of disrupted nocturnal sleep in 170 adults." }, { "docid": "1471041", "text": "Celiac disease is an immune-mediated disorder in which mucosal autoantibodies to the enzyme transglutaminase 2 (TG2) are generated in response to the exogenous antigen gluten in individuals who express human leukocyte antigen HLA-DQ2 or HLA-DQ8 (ref. 3). We assessed in a comprehensive and nonbiased manner the IgA anti-TG2 response by expression cloning of the antibody repertoire of ex vivo–isolated intestinal antibody-secreting cells (ASCs). We found that TG2-specific plasma cells are markedly expanded within the duodenal mucosa in individuals with active celiac disease. TG2-specific antibodies were of high affinity yet showed little adaptation by somatic mutations. Unlike infection-induced peripheral blood plasmablasts, the TG2-specific ASCs had not recently proliferated and were not short-lived ex vivo. Altogether, these observations demonstrate that there is a germline repertoire with high affinity for TG2 that may favor massive generation of autoreactive B cells. TG2-specific antibodies did not block enzymatic activity and served as substrates for TG2-mediated crosslinking when expressed as IgD or IgM but not as IgA1 or IgG1. This could result in preferential recruitment of plasma cells from naive IgD- and IgM-expressing B cells, thus possibly explaining why the antibody response to TG2 bears signs of a primary immune response despite the disease chronicity.", "title": "High abundance of plasma cells secreting transglutaminase 2–specific IgA autoantibodies with limited somatic hypermutation in celiac disease intestinal lesions" }, { "docid": "21060008", "text": "OBJECTIVE To assay the efficiency for celiac disease (CD) screening of 2 immunochromatographic visual stick assays based on human recombinant tissue transglutaminase (tTG). One was the antitissue transglutaminase antibodies (AtTGA) stick for IgA/G antibodies to tTG detection, the other was the AtTGA/antigliadin antibodies (AGA) stick for IgA antibodies for tTG and/or gliadins. \n PATIENTS AND METHODS In a prospective multicenter study, 4 pediatric gastroenterology units from Spain and 2 from Latin America enrolled 72 control children with a normal small bowel mucosa and 113 untreated patients with CD with Marsh type 3 lesions. \n RESULTS Evaluation of results by the gastroenterologists and by 2 independent observers at the coordination center showed a remarkably low interobserver variability. For the AtTGA stick, sensitivity was 96.5% and specificity was 98.6%. The AtTGA/AGA stick displayed a sensitivity of 94.5% and a specificity of 98.6% for AtTGA and a sensitivity of 63.1% and a specificity of 95.2% for AGA. The highest efficiency and positive likelihood ratio was obtained for the AtTGA stick, higher than for IgA AtTGA by enzyme-linked immunosorbent assay. One additional advantage was that previous investigation of total serum IgA levels could be eluded. The IgA AtTGA/AGA stick, with an efficiency of 95.1%, compared with 89.2% when the combined results of the 2 enzyme-linked immunosorbent assays were considered, turned out to be an excellent diagnostic tool for infants with no IgA deficiency. \n CONCLUSION These 2 assays are extremely efficient for CD screening, by combining a high diagnostic accuracy with the simplicity and rapidity of visual methods.", "title": "Celiac disease screening by immunochromatographic visual assays: results of a multicenter study." }, { "docid": "44420873", "text": "The predominant form of the cross-linking enzyme, transglutaminase, in cultured normal human epidermal keratinocytes, is found in cell particulate material and can be solubilized by nonionic detergent. It elutes as a single peak upon either anion-exchange or gel-filtration chromatography. Monoclonal antibodies raised to the particulate enzyme cross-react with one of two transglutaminases in the cell cytosol. The second cytosolic transglutaminase, which has distinct kinetic and physical properties from the first, does not cross-react and is not essential for formation of the keratinocyte cross-linked envelope in vitro. The anti-transglutaminase antibodies stain the more differentiated layers of epidermis in a pattern similar to that given by anti-involucrin antiserum. These observations support the hypothesis that the transglutaminase so identified is involved in cross-linked envelope formation in vivo.", "title": "Keratinocyte-specific transglutaminase of cultured human epidermal cells: relation to cross-linked envelope formation and terminal differentiation." }, { "docid": "25519138", "text": "Bacteria such as Escherichia coli will often consume one sugar at a time when fed multiple sugars, in a process known as carbon catabolite repression. The classic example involves glucose and lactose, where E. coli will first consume glucose, and only when it has consumed all of the glucose will it begin to consume lactose. In addition to that of lactose, glucose also represses the consumption of many other sugars, including arabinose and xylose. In this work, we characterized a second hierarchy in E. coli, that between arabinose and xylose. We show that, when grown in a mixture of the two pentoses, E. coli will consume arabinose before it consumes xylose. Consistent with a mechanism involving catabolite repression, the expression of the xylose metabolic genes is repressed in the presence of arabinose. We found that this repression is AraC dependent and involves a mechanism where arabinose-bound AraC binds to the xylose promoters and represses gene expression. Collectively, these results demonstrate that sugar utilization in E. coli involves multiple layers of regulation, where cells will consume first glucose, then arabinose, and finally xylose. These results may be pertinent in the metabolic engineering of E. coli strains capable of producing chemical and biofuels from mixtures of hexose and pentose sugars derived from plant biomass.", "title": "Regulation of arabinose and xylose metabolism in Escherichia coli." }, { "docid": "17695748", "text": "Transglutaminase 2 (TGase 2) is a Ca+2-dependent enzyme that catalyzes both intracellular and extracellular cross-linking reactions by transamidation of specific glutamine residues. TGase 2 is known to be involved in the membrane-mediated events required for glucose-stimulated insulin release from the pancreatic beta cells. Here we show that targeted disruption of TGase 2 impairs glucose-stimulated insulin secretion. TGase 2-/- mice show glucose intolerance after intraperitoneal glucose loading. TGase 2-/- mice manifest a tendency to develop hypoglycemia after administration of exogenous insulin as a consequence of enhanced insulin receptor substrate 2 (IRS-2) phosphorylation. We suggest that the increased peripheral sensitivity to insulin partially compensates for the defective secretion in this animal model. TGase 2-/- mouse phenotype resembles that of the maturity-onset diabetes of young (MODY) patients. In the course of screening for human TGase 2 gene in Italian subjects with the clinical features of MODY, we detected a missense mutation (N333S) in the active site of the enzyme. Collectively, these results identify TGase 2 as a potential candidate gene in type 2 diabetes.", "title": "in" }, { "docid": "2335873", "text": "Bacterial chondroitinase ABC (ChaseABC) has been used to remove the inhibitory chondroitin sulfate chains from chondroitin sulfate proteoglycans to improve regeneration after rodent spinal cord injury. We hypothesized that the mammalian enzyme arylsulfatase B (ARSB) would also enhance recovery after mouse spinal cord injury. Application of the mammalian enzyme would be an attractive alternative to ChaseABC because of its more robust chemical stability and reduced immunogenicity. A one-time injection of human ARSB into injured mouse spinal cord eliminated immunoreactivity for chondroitin sulfates within five days, and up to 9 weeks after injury. After a moderate spinal cord injury, we observed improvements of locomotor recovery assessed by the Basso Mouse Scale (BMS) in ARSB treated mice, compared to the buffer-treated control group, at 6 weeks after injection. After a severe spinal cord injury, mice injected with equivalent units of ARSB or ChaseABC improved similarly and both groups achieved significantly more locomotor recovery than the buffer-treated control mice. Serotonin and tyrosine hydroxylase immunoreactive axons were more extensively present in mouse spinal cords treated with ARSB and ChaseABC, and the immunoreactive axons penetrated further beyond the injury site in ARSB or ChaseABC treated mice than in control mice. These results indicate that mammalian ARSB improves functional recovery after CNS injury. The structural/molecular mechanisms underlying the observed functional improvement remain to be elucidated.", "title": "Arylsulfatase B Improves Locomotor Function after Mouse Spinal Cord Injury" }, { "docid": "27772649", "text": "BACKGROUND & AIMS Celiac disease is characterized by disturbed jejunal crypt-villus axis biology with immunoglobulin (Ig) A deposits underlining the epithelium. The aim of this study was to test whether celiac disease serum IgA (reticulin/endomysial autoantibodies) interferes with the mesenchymal-epithelial cell cross-talk. \n METHODS Differentiation of T84 epithelial cells was induced with IMR-90 fibroblasts or transforming growth factor beta in three-dimensional collagen gel cultures. The effects of purified celiac IgA and monoclonal tissue transglutaminase antibodies (CUB7402) were studied by adding the antibodies to the cocultures. \n RESULTS Active celiac disease IgA, reactive for tissue transglutaminase, significantly inhibited T84 epithelial cell differentiation (P < 0.001) and increased epithelial cell proliferation (P = 0.024). Similar effects were obtained with antibodies against tissue transglutaminase. \n CONCLUSIONS Celiac disease-associated IgA class antibodies disturb transforming growth factor beta-mediated fibroblast-epithelial cell cross-talk in this in vitro crypt-villus axis model. This primary finding indicates that celiac disease-specific autoantibodies may also contribute to the formation of the gluten-triggered jejunal mucosal lesion in celiac disease.", "title": "Serum immunoglobulin A from patients with celiac disease inhibits human T84 intestinal crypt epithelial cell differentiation." }, { "docid": "25238950", "text": "Fibroblast growth factors (FGFs) have mitogenic activity toward a wide variety of cells of mesenchymal, neuronal, and epithelial origin and regulate events in normal embryonic development, angiogenesis, wound repair, and neoplasia. FGF-2 is expressed in many normal adult tissues and can regulate migration and replication of intestinal epithelial cells in culture. However, little is known about the effects of FGF-2 on intestinal epithelial stem cells during either normal epithelial renewal or regeneration of a functional epithelium after injury. In this study, we investigated the expression of FGF-2 in the mouse small intestine after irradiation and determined the effect of exogenous FGF-2 on crypt stem cell survival after radiation injury. Expression of FGF-2 mRNA and protein began to increase at 12 h after gamma-irradiation, and peak levels were observed from 48 to 120 h after irradiation. At all times after irradiation, the higher molecular mass isoform ( approximately 24 kDa) of FGF-2 was the predominant form expressed in the small intestine. Immunohistochemical analysis of FGF-2 expression after radiation injury demonstrated that FGF-2 was predominantly found in the mesenchyme surrounding regenerating crypts. Exogenous recombinant human FGF-2 (rhFGF-2) markedly enhanced crypt stem cell survival when given before irradiation. We conclude that expression of FGF-2 is induced by radiation injury and that rhFGF-2 can enhance crypt stem cell survival after subsequent injury.", "title": "FGF-2 enhances intestinal stem cell survival and its expression is induced after radiation injury." }, { "docid": "20935673", "text": "Spatial boundaries of homeotic gene expression are initiated and maintained by two sets of transcriptional repressors: the gap gene products and the Polycomb group proteins. Previously, the Hunchback (HB) protein has been implicated in setting the anterior expression limit of the UBX homeotic protein in parasegment 6. Here we investigate DNA elements and trans-acting repressors that control spatial expression of the Abdominal-A (ABD-A) homeotic protein. Analysis of a 1.7-kb enhancer element [iab-2(1.7)] from the iab-2 regulatory region shows that in contrast to Ubx enhancer elements, both HB and Krüppel (KR) are required to set the ABD-A anterior boundary in parasegment 7. DNase I footprinting and site-directed mutagenesis show that HB and KR are direct regulators of this iab-2 enhancer. The single KR site can be moved to a new location 100 bp away and still maintain repressive activity, whereas relocation by 300 bp abolishes activity. These results suggest that KR repression occurs through a local quenching mechanism. We also show that the gap repressor Giant (GT) initially establishes a posterior expression limit at PS9, which shifts posteriorly after the blastoderm stage. Finally, we show that this iab-2 enhancer contains multiple binding sites for the Polycomb group protein Pleiohomeotic (PHO). These iab-2 PHO sites are required in vivo for chromosome pairing-dependent repression of a mini-white reporter. However, the PHO sites are not sufficient to maintain repression of a homeotic reporter gene anterior to PS7. Full maintenance at late embryonic stages requires additional sequences adjacent to the iab-2(1.7) enhancer.", "title": "Functional analysis of repressor binding sites in the iab-2 regulatory region of the abdominal-A homeotic gene." }, { "docid": "95764370", "text": "Abstract In this paper, growth and characterization of CdS thin films by Chemical Bath Deposition (CBD) technique using the reaction between CdCl 2 , (NH 2 ) 2 CS and NH 3 in an aqueous solution has been reported. The parameters actively involved in the process of deposition have been identified. A commonly available CBD system has been sucessfully modified to obtain the precious control over the pH of the solution at 90°C during the deposition and studies have been made to understand the fundamental parameters like concentrations of the solution, pH and temperature of the solution involved in the chemical bath deposition of CdS. It is confirmed that the pH of the solution plays a vital role in the quality of the CBD–CdS films. Structural, optical and electrical properties have been analysed for the as-deposited and annealed films. XRD studies on the CBD–CdS films reveal that the change in Cadmium ion concentration in the bath results in the change in crystallization from cubic phase with (1 1 1) predominant orientation to a hexagonal phase with (0 0 2) predominant orientation. The structural changes due to varying cadmium ion concentration in the bath affects the optical and electrical properties. Optimum electrical resistivity, band gap and refractive index value are observed for the annealed films deposited from 0.8 M cadmium ion concentration. The films are suitable for solar cell fabrication. Further on, annealing the samples at 350°C in H 2 for 30 min resulted in an increased diffraction intensity as well as shifts in the peak towards lower scattering angles due to enlarged CdS unit cell. This in turn brought about an increase in the lattice parameters and narrowing in the band-gap values. The results are compared with the analysis of previous work.", "title": "Modification in the chemical bath deposition apparatus, growth and characterization of CdS semiconducting thin films for photovoltaic applications" }, { "docid": "14380875", "text": "Glucocorticoids repress NFkappaB-mediated activation of proinflammatory genes such as interleukin-8 (IL-8) and ICAM-1. Our experiments suggest that the glucocorticoid receptor (GR) confers this effect by associating through protein-protein interactions with NFkappaB bound at each of these genes. That is, we show that the GR zinc binding region (ZBR), which includes the DNA binding and dimerization functions of the receptor, binds directly to the dimerization domain of the RelA subunit of NFkappaB in vitro and that the ZBR is sufficient to associate with RelA bound at NFkappaB response elements in vivo. Moreover, we demonstrate in vivo and in vitro that GR does not disrupt DNA binding by NFkappaB. In transient transfections, we found that the GR ligand binding domain is essential for repression of NFkappaB but not for association with it and that GR can repress an NFkappaB derivative bearing a heterologous activation domain. We used chromatin immunoprecipitation assays in untransfected A549 cells to infer the mechanism by which the tethered GR represses NFkappaB-activated transcription. As expected, we found that the inflammatory signal TNFalpha stimulated preinitiation complex (PIC) assembly at the IL-8 and ICAM-1 promoters and that the largest subunit of RNA polymerase II (pol II) in those complexes became phosphorylated at serines 2 and 5 in its carboxy-terminal domain (CTD) heptapeptide repeats (YSPTSPS); these modifications are required for transcription initiation. Remarkably, GR did not inhibit PIC assembly under repressing conditions, but rather interfered with phosphorylation of serine 2 of the pol II CTD.", "title": "The Glucocorticoid Receptor Inhibits" }, { "docid": "15521377", "text": "Cellular senescence is a stable form of cell-cycle arrest which is thought to limit the proliferative potential of premalignant cells [1]. The senescence phenotype was initially described by Hayflick and Moorhead in 1961 on human fibroblasts undergoing replicative exhaustion in culture [2]. It has been shown that senescence can be triggered in different cell types in response to diverse forms of cellular damage or stress (for review see [1]). Importantly, while senescence was denounced as a tissue culture phenomenon for many years, recent in vivo studies demonstrated that cellular senescence represents a potent failsafe mechanism against tumorigenesis and contributes to the cytotoxicity of certain anticancer agents (see for example [3-7]). Interestingly, senescent cells have also been observed in certain aged or damaged tissues and there is growing evidence that senescence checkpoints can affect the regenerative reserve of tissues and organismal aging [8-11]. However, senescence may also have positive effects on organ maintenance by limiting pathological responses to acute forms of injury such as fibrotic scarring in response to chemical induced liver injury [12]. Over the past years it was also shown that senescent cells can communicate with their environment by secreting a myriad of cytokines and growth factors. Interestingly, this \"senescence associated secretory phenotype (SASP)\" seems to be a double edged sword regarding tumor initiation and maintenance: i) On the one hand, it has been shown that the SASP can have pro-tumorigenic effects. In an experimental system it was shown that senescent mesenchymal cells can enhance the tumorigenicity of surrounding breast cancer cells [13]. ii) Similarly, it is possible that the SASP enhances selection of transformed cell clones in aged organ systems. It has been shown that loss of proliferative competition of non-transformed cells can accelerate leukemogenesis [14]. It remains to be seen whether aberrant secretion of cytokines and growth factors by the SASP can accelerated this process in aged and chronically damage organ systems. iii) In contrast to its pro-tumorigenic aspect, the SASP could also have anti-tumor effects. A recent study showed that in a mosaic liver cancer mouse model the activation of p53 induced senescence, an upregulation of inflammatory cytokines, and activation of innate immune responses leading to tumour cell clearance [15]. iv) In further support that the SASP could have anti-tumor activities, a series of recent papers showed that components of the SASP can stabilize the senescence cell cycle arrest via an autoregulatory feedback loop [16,17] or induces apoptosis of tumor cells [18]. In addition to its effects on tumorigenesis, the SASP could also influence tissue aging. Studies on aging telomere dysfunctional mice have provided direct experimental evidence for an in vivo activation of the SASP in response to telomere dysfunction [19]. Interestingly, this in vivo SASP provoked alterations in stem cell differentiation (skewing of hematopoiesis towards reduction in lymphopoiesis and enhancement of myelopoiesis) that are also characteristic signs of human aging. Figure 1. Different cellular stresses can induce senescence including telomere shortening, DNA damage, and oncogene activation. Senescence of tumor cells ... In light of the many possible roles o the SASP in aging and carcinogenesis, it appears to be of utmost importance to decipher regulatory pathways controlling the SASP. In a current publication, Bhaumik et al. have identified 2 microRNAs (miR-146a/b) that negatively regulate the secretion of IL-6 and IL-8 - two of the SASP [20]. The authors show that these microRNAs are up-regulated at late stages of senescence, many days after a permanent cell cycle arrest has been established. Interestingly, the inhibitory miRs are most strongly up-regulated in senescence of cell lines that show a strong SASP but not in cell lines characterized by a weak SASP. The authors propose a new concept indicating that miRs 146a and b function in a negative feedback loop preventing an over-activation of the SASP in senescent cells. The authors present some initial data suggesting that activation of this negative feedback loop involves IL-1 receptor, IRAK-1, and NFκB signalling leading to an up-regulation of miRs-146a and b. A direct proof that this proposed feedback loop suppresses over-activation of the SASP remains to be demonstrated in future studies. The authors show that blockage of IL-1-receptor signalling prevents both the up-regulation of miRs-146a and b as well as Il-6 secretion. To confirm their new concept, it would be important to show that a selective blockage of miRs-146a and b results in over-activation of the SASP. The work by Bhaumik et al. places mir-146a/b as central players to control IL-6 and IL-8 expression within the SASP. MicroRNAs are emerging therapeutic targets because their expression levels can be effectively modulated via the use of antagomirs (see for example [21]). Also, for increasing microRNA expression, microRNAs can be delivered into cellsin vivo (see for example [22]). Therefore, it will be interesting to functionally test the impact of mir-146 inhibition on tumorigenesis and aging in relevant mouse models. Such studies will be of particular interest, as recent work showed that IL-6 secretion by senescent cells is relevant for initiating and maintaining the senescene response via an autocrine loop [17]. A reduction of miR-146 could increase IL-6 levels in senescent cells, which should stabilize the senescence program and reduce the risk of malignant transformation. Furthermore, it can be speculated that reduction of mir-146 a/b will increase NfκB activation via IRAK1. As NfκB is modulating the expression of various inflammation associated genes, this may also lead to increased clearance of senescent tumor cells by the innate immune system. However, it should be mentioned that Il-6 secreted by senescent cells can also act as a mitogen for surrounding cells, thus potentially increasing the risk of malignant transformation [13,17]. Besides its function in SASP modulation, miR-146 was also reported to target the mRNAs of the BRCA1 and BRCA2 tumor suppressors. In a recent study a G to C polymorphism in miR-146, which leads to an increased processing and release of the mature microRNA, can predict an early onset of breast cancer [23]. Taken together, the study of Bhaumik et al. opens an interesting new research area dealing with the gene regulatory mechanisms that control activation of the SASP. Given the diverse roles of the SASP in modulating tumor progression, immune surveillance of damaged cells, and the stabilization of the senescence arrest itself, it will be of great interest to analyse the influence of SASP regulatory pathways during aging and cancer.", "title": "Keeping your senescent cells under control" }, { "docid": "8002887", "text": "Autophagy is the primary catabolic process triggered in response to starvation. Although autophagic regulation within the cytosolic compartment is well established, it is becoming clear that nuclear events also regulate the induction or repression of autophagy. Nevertheless, a thorough understanding of the mechanisms by which sequence-specific transcription factors modulate expression of genes required for autophagy is lacking. Here, we identify Foxk proteins (Foxk1 and Foxk2) as transcriptional repressors of autophagy in muscle cells and fibroblasts. Interestingly, Foxk1/2 serve to counter-balance another forkhead transcription factor, Foxo3, which induces an overlapping set of autophagic and atrophic targets in muscle. Foxk1/2 specifically recruits Sin3A-HDAC complexes to restrict acetylation of histone H4 and expression of critical autophagy genes. Remarkably, mTOR promotes the transcriptional activity of Foxk1 by facilitating nuclear entry to specifically limit basal levels of autophagy in nutrient-rich conditions. Our study highlights an ancient, conserved mechanism whereby nutritional status is interpreted by mTOR to restrict autophagy by repressing essential autophagy genes through Foxk-Sin3-mediated transcriptional control.", "title": "Foxk proteins repress the initiation of starvation-induced atrophy and autophagy programs" }, { "docid": "17945638", "text": "Polycomb group proteins are essential for early development in metazoans, but their contributions to human development are not well understood. We have mapped the Polycomb Repressive Complex 2 (PRC2) subunit SUZ12 across the entire nonrepeat portion of the genome in human embryonic stem (ES) cells. We found that SUZ12 is distributed across large portions of over two hundred genes encoding key developmental regulators. These genes are occupied by nucleosomes trimethylated at histone H3K27, are transcriptionally repressed, and contain some of the most highly conserved noncoding elements in the genome. We found that PRC2 target genes are preferentially activated during ES cell differentiation and that the ES cell regulators OCT4, SOX2, and NANOG cooccupy a significant subset of these genes. These results indicate that PRC2 occupies a special set of developmental genes in ES cells that must be repressed to maintain pluripotency and that are poised for activation during ES cell differentiation.", "title": "Control of Developmental Regulators by Polycomb in Human Embryonic Stem Cells" }, { "docid": "6308416", "text": "Coordinated cell movements in epithelial layers are essential for proper tissue morphogenesis and homeostasis, but our understanding of the mechanisms that coordinate the behavior of multiple cells in these processes is far from complete. Recent experiments with Madin-Darby canine kidney epithelial monolayers revealed a wave-like pattern of injury-induced MAPK activation and showed that it is essential for collective cell migration after wounding. To investigate the effects of the different aspects of wounding on cell sheet migration, we engineered a system that allowed us to dissect the classic wound healing assay. We studied Madin-Darby canine kidney sheet migration under three different conditions: 1) the classic wound healing assay, 2) empty space induction, where a confluent monolayer is grown adjacent to a slab of polydimethylsiloxane and the monolayer is not injured but allowed to migrate upon removal of the slab, and 3) injury via polydimethylsiloxane membrane peel-off, where an injured monolayer migrates onto plain tissue culture surface, as in the case of empty space induction allowing for direct comparison. By tracking the motion of individual cells within the sheet under these three conditions, we show how the dynamics of the individual cells' motion is responsible for the coordinated migration of the sheet and is coordinated with the activation of ERK1/2 MAPK. In addition, we demonstrate that the propagation of the waves of MAPK activation depends on the generation of reactive oxygen species at the wound edge.", "title": "Role of boundary conditions in an experimental model of epithelial wound healing." } ]

[ { "docid": "1568684", "text": "The interest in brown adipose tissue (BAT) as a target to combat metabolic disease has recently been renewed with the discovery of functional BAT in humans. In rodents, BAT can be activated by bile acids, which activate type 2 iodothyronine deiodinase (D2) in BAT via the G-coupled protein receptor TGR5, resulting in increased oxygen consumption and energy expenditure. Here we examined the effects of oral supplementation of the bile acid chenodeoxycholic acid (CDCA) on human BAT activity. Treatment of 12 healthy female subjects with CDCA for 2 days resulted in increased BAT activity. Whole-body energy expenditure was also increased upon CDCA treatment. In vitro treatment of primary human brown adipocytes derived with CDCA or specific TGR5 agonists increased mitochondrial uncoupling and D2 expression, an effect that was absent in human primary white adipocytes. These findings identify bile acids as a target to activate BAT in humans.", "title": "The Bile Acid Chenodeoxycholic Acid Increases Human Brown Adipose Tissue Activity." } ]

[ { "docid": "4319174", "text": "All homeotherms use thermogenesis to maintain their core body temperature, ensuring that cellular functions and physiological processes can continue in cold environments. In the prevailing model of thermogenesis, when the hypothalamus senses cold temperatures it triggers sympathetic discharge, resulting in the release of noradrenaline in brown adipose tissue and white adipose tissue. Acting via the β(3)-adrenergic receptors, noradrenaline induces lipolysis in white adipocytes, whereas it stimulates the expression of thermogenic genes, such as PPAR-γ coactivator 1a (Ppargc1a), uncoupling protein 1 (Ucp1) and acyl-CoA synthetase long-chain family member 1 (Acsl1), in brown adipocytes. However, the precise nature of all the cell types involved in this efferent loop is not well established. Here we report in mice an unexpected requirement for the interleukin-4 (IL-4)-stimulated program of alternative macrophage activation in adaptive thermogenesis. Exposure to cold temperature rapidly promoted alternative activation of adipose tissue macrophages, which secrete catecholamines to induce thermogenic gene expression in brown adipose tissue and lipolysis in white adipose tissue. Absence of alternatively activated macrophages impaired metabolic adaptations to cold, whereas administration of IL-4 increased thermogenic gene expression, fatty acid mobilization and energy expenditure, all in a macrophage-dependent manner. Thus, we have discovered a role for alternatively activated macrophages in the orchestration of an important mammalian stress response, the response to cold.", "title": "Alternatively activated macrophages produce catecholamines to sustain adaptive thermogenesis" }, { "docid": "14865329", "text": "Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders.", "title": "Brown Fat and Browning for the Treatment of Obesity and Related Metabolic Disorders" }, { "docid": "52865789", "text": "OBJECTIVE IL-15 is an inflammatory cytokine secreted by many cell types. IL-15 is also produced during physical exercise by skeletal muscle and has been reported to reduce weight gain in mice. Contrarily, our findings on IL-15 knockout (KO) mice indicate that IL-15 promotes obesity. The aim of this study is to investigate the mechanisms underlying the pro-obesity role of IL-15 in adipose tissues. \n METHODS Control and IL-15 KO mice were maintained on high fat diet (HFD) or normal control diet. After 16 weeks, body weight, adipose tissue and skeletal mass, serum lipid levels and gene/protein expression in the adipose tissues were evaluated. The effect of IL-15 on thermogenesis and oxygen consumption was also studied in primary cultures of adipocytes differentiated from mouse preadipocyte and human stem cells. \n RESULTS Our results show that IL-15 deficiency prevents diet-induced weight gain and accumulation of lipids in visceral and subcutaneous white and brown adipose tissues. Gene expression analysis also revealed elevated expression of genes associated with adaptive thermogenesis in the brown and subcutaneous adipose tissues of IL-15 KO mice. Accordingly, oxygen consumption was increased in the brown adipocytes from IL-15 KO mice. In addition, IL-15 KO mice showed decreased expression of pro-inflammatory mediators in their adipose tissues. \n CONCLUSIONS Absence of IL-15 results in decreased accumulation of fat in the white adipose tissues and increased lipid utilization via adaptive thermogenesis. IL-15 also promotes inflammation in adipose tissues that could sustain chronic inflammation leading to obesity-associated metabolic syndrome.", "title": "Deficiency of Interleukin-15 Confers Resistance to Obesity by Diminishing Inflammation and Enhancing the Thermogenic Function of Adipose Tissues" }, { "docid": "29691654", "text": "Until recently, the mechanism of adaptive thermogenesis was ascribed to the expression of uncoupling protein 1 (UCP1) in brown and beige adipocytes. UCP1 is known to catalyze a proton leak of the inner mitochondrial membrane, resulting in uncoupled oxidative metabolism with no production of adenosine triphosphate and increased energy expenditure. Thus increasing brown and beige adipose tissue with augmented UCP1 expression is a viable target for obesity-related disorders. Recent work demonstrates an UCP1-independent pathway to uncouple mitochondrial respiration. A secreted enzyme, PM20D1, enriched in UCP1+ adipocytes, exhibits catalytic and hydrolytic activity to reversibly form N-acyl amino acids. N-acyl amino acids act as endogenous uncouplers of mitochondrial respiration at physiological concentrations. Administration of PM20D1 or its products, N-acyl amino acids, to diet-induced obese mice improves glucose tolerance by increasing energy expenditure. In short-term studies, treated animals exhibit no toxicity while experiencing 10% weight loss primarily of adipose tissue. Further study of this metabolic pathway may identify novel therapies for diabesity, the disease state associated with diabetes and obesity.", "title": "Uncoupling Mitochondrial Respiration for Diabesity." }, { "docid": "29381091", "text": "Brown adipocytes dissipate energy, whereas white adipocytes are an energy storage site. We explored the plasticity of different white adipose tissue depots in acquiring a brown phenotype by cold exposure. By comparing cold-induced genes in white fat to those enriched in brown compared with white fat, at thermoneutrality we defined a \"brite\" transcription signature. We identified the genes, pathways, and promoter regulatory motifs associated with \"browning,\" as these represent novel targets for understanding this process. For example, neuregulin 4 was more highly expressed in brown adipose tissue and upregulated in white fat upon cold exposure, and cell studies showed that it is a neurite outgrowth-promoting adipokine, indicative of a role in increasing adipose tissue innervation in response to cold. A cell culture system that allows us to reproduce the differential properties of the discrete adipose depots was developed to study depot-specific differences at an in vitro level. The key transcriptional events underpinning white adipose tissue to brown transition are important, as they represent an attractive proposition to overcome the detrimental effects associated with metabolic disorders, including obesity and type 2 diabetes.", "title": "Brown and white adipose tissues: intrinsic differences in gene expression and response to cold exposure in mice" }, { "docid": "36838958", "text": "Uncoupling protein 1 (Ucp1), which is localized in the mitochondrial inner membrane of mammalian brown adipose tissue (BAT), generates heat by uncoupling oxidative phosphorylation. Upon cold exposure or nutritional abundance, sympathetic neurons stimulate BAT to express Ucp1 to induce energy dissipation and thermogenesis. Accordingly, increased Ucp1 expression reduces obesity in mice and is correlated with leanness in humans. Despite this significance, there is currently a limited understanding of how Ucp1 expression is physiologically regulated at the molecular level. Here, we describe the involvement of Sestrin2 and reactive oxygen species (ROS) in regulation of Ucp1 expression. Transgenic overexpression of Sestrin2 in adipose tissues inhibited both basal and cold-induced Ucp1 expression in interscapular BAT, culminating in decreased thermogenesis and increased fat accumulation. Endogenous Sestrin2 is also important for suppressing Ucp1 expression because BAT from Sestrin2(-/-) mice exhibited a highly elevated level of Ucp1 expression. The redox-inactive mutant of Sestrin2 was incapable of regulating Ucp1 expression, suggesting that Sestrin2 inhibits Ucp1 expression primarily through reducing ROS accumulation. Consistently, ROS-suppressing antioxidant chemicals, such as butylated hydroxyanisole and N-acetylcysteine, inhibited cold- or cAMP-induced Ucp1 expression as well. p38 MAPK, a signaling mediator required for cAMP-induced Ucp1 expression, was inhibited by either Sestrin2 overexpression or antioxidant treatments. Taken together, these results suggest that Sestrin2 and antioxidants inhibit Ucp1 expression through suppressing ROS-mediated p38 MAPK activation, implying a critical role of ROS in proper BAT metabolism.", "title": "Sestrin2 inhibits uncoupling protein 1 expression through suppressing reactive oxygen species." }, { "docid": "3621011", "text": "Proper regulation of energy storage in adipose tissue is crucial for maintaining insulin sensitivity and molecules contributing to this process have not been fully revealed. Here we show that type II transmembrane protein tenomodulin (TNMD) is upregulated in adipose tissue of insulin-resistant versus insulin-sensitive individuals, who were matched for body mass index (BMI). TNMD expression increases in human preadipocytes during differentiation, whereas silencing TNMD blocks adipogenesis. Upon high-fat diet feeding, transgenic mice overexpressing Tnmd develop increased epididymal white adipose tissue (eWAT) mass, and preadipocytes derived from Tnmd transgenic mice display greater proliferation, consistent with elevated adipogenesis. In Tnmd transgenic mice, lipogenic genes are upregulated in eWAT, as is Ucp1 in brown fat, while liver triglyceride accumulation is attenuated. Despite expanded eWAT, transgenic animals display improved systemic insulin sensitivity, decreased collagen deposition and inflammation in eWAT, and increased insulin stimulation of Akt phosphorylation. Our data suggest that TNMD acts as a protective factor in visceral adipose tissue to alleviate insulin resistance in obesity.", "title": "Tenomodulin promotes human adipocyte differentiation and beneficial visceral adipose tissue expansion." }, { "docid": "6227220", "text": "Despite growing interest and a recent surge in papers, the role of autophagy in glucose and lipid metabolism is unclear. We produced mice with skeletal muscle–specific deletion of Atg7 (encoding autophagy-related 7). Unexpectedly, these mice showed decreased fat mass and were protected from diet-induced obesity and insulin resistance; this phenotype was accompanied by increased fatty acid oxidation and browning of white adipose tissue (WAT) owing to induction of fibroblast growth factor 21 (Fgf21). Mitochondrial dysfunction induced by autophagy deficiency increased Fgf21 expression through induction of Atf4, a master regulator of the integrated stress response. Mitochondrial respiratory chain inhibitors also induced Fgf21 in an Atf4-dependent manner. We also observed induction of Fgf21, resistance to diet-induced obesity and amelioration of insulin resistance in mice with autophagy deficiency in the liver, another insulin target tissue. These findings suggest that autophagy deficiency and subsequent mitochondrial dysfunction promote Fgf21 expression, a hormone we consequently term a 'mitokine', and together these processes promote protection from diet-induced obesity and insulin resistance.", "title": "Autophagy deficiency leads to protection from obesity and insulin resistance by inducing Fgf21 as a mitokine" }, { "docid": "17973161", "text": "Uncoupling protein 1 (UCP1) is highly expressed in brown adipose tissue, where it generates heat by uncoupling electron transport from ATP production. UCP1 is also found outside classical brown adipose tissue depots, in adipocytes that are termed 'brite' (brown-in-white) or 'beige'. In humans, the presence of brite or beige (brite/beige) adipocytes is correlated with a lean, metabolically healthy phenotype, but whether a causal relationship exists is not clear. Here we report that human brite/beige adipocyte progenitors proliferate in response to pro-angiogenic factors, in association with expanding capillary networks. Adipocytes formed from these progenitors transform in response to adenylate cyclase activation from being UCP1 negative to being UCP1 positive, which is a defining feature of the beige/brite phenotype, while displaying uncoupled respiration. When implanted into normal chow-fed, or into high-fat diet (HFD)-fed, glucose-intolerant NOD-scid IL2rg(null) (NSG) mice, brite/beige adipocytes activated in vitro enhance systemic glucose tolerance. These adipocytes express neuroendocrine and secreted factors, including the pro-protein convertase PCSK1, which is strongly associated with human obesity. Pro-angiogenic conditions therefore drive the proliferation of human beige/brite adipocyte progenitors, and activated beige/brite adipocytes can affect systemic glucose homeostasis, potentially through a neuroendocrine mechanism.", "title": "Human ‘brite / beige’ adipocytes develop from capillary networks and their implantation improves metabolic homeostasis in mice" }, { "docid": "2605032", "text": "We investigated if whether intrauterine protein restriction in combination with overfeeding during lactation would cause adult-onset obesity and metabolic disorders. After birth, litters from dams fed with control (17% protein) and low protein (6% protein) diets were adjusted to a size of four (CO and LO groups, respectively) or eight (CC and LC groups, respectively) pups. All of the offspring were fed a diet containing 12% protein from the time of weaning until they were 90 d old. Compared to the CC and LC groups, the CO and LO groups had higher relative and absolute food intakes, oxygen consumption and carbon dioxide production; lower brown adipose tissue weight and lipid content and greater weight gain and absolute and relative white adipose tissue weight and absolute lipid content. Compared with the CO and CC rats, the LC and LO rats exhibited higher relative food intake, brown adipose tissue weight and lipid content, reduced oxygen consumption, carbon dioxide production and spontaneous activity, increased relative retroperitoneal adipose tissue weight and unaltered absolute white adipose tissue weight and lipid content. The fasting serum glucose was similar among the groups. The area under the glucose curve was higher in the LO and CO rats than in the LC and CC rats. The basal insulinemia and homeostasis model assessment of insulin resistance (HOMA-IR) were lower in the LO group than in the other groups. The total area under the insulin curve for the LO rats was similar to the CC rats, and both were lower than the CO and LC rats. Kitt was higher in the LO, LC and CO groups than in the CC group. Thus, intrauterine protein restriction followed by overfeeding during lactation did not induce obesity, but produced glucose intolerance by impairing pancreatic function in adulthood.", "title": "Intrauterine protein restriction combined with early postnatal overfeeding was not associated with adult-onset obesity but produced glucose intolerance by pancreatic dysfunction" }, { "docid": "26902591", "text": "Cancer-associated cachexia (CAC) is a wasting syndrome characterized by systemic inflammation, body weight loss, atrophy of white adipose tissue (WAT) and skeletal muscle. Limited therapeutic options are available and the underlying mechanisms are poorly defined. Here we show that a phenotypic switch from WAT to brown fat, a phenomenon termed WAT browning, takes place in the initial stages of CAC, before skeletal muscle atrophy. WAT browning is associated with increased expression of uncoupling protein 1 (UCP1), which uncouples mitochondrial respiration toward thermogenesis instead of ATP synthesis, leading to increased lipid mobilization and energy expenditure in cachectic mice. Chronic inflammation and the cytokine interleukin-6 increase UCP1 expression in WAT, and treatments that reduce inflammation or β-adrenergic blockade reduce WAT browning and ameliorate the severity of cachexia. Importantly, UCP1 staining is observed in WAT from CAC patients. Thus, inhibition of WAT browning represents a promising approach to ameliorate cachexia in cancer patients.", "title": "A switch from white to brown fat increases energy expenditure in cancer-associated cachexia." }, { "docid": "40232172", "text": "The research on mitochondrial functions in adipocytes has increasingly evidenced that mitochondria plays an important role in the onset and/or progression of obesity and related pathologies. Mitochondrial function in brown adipose tissue (BAT) has been classically assessed by measuring either the levels/activity of mitochondrial enzymes, or the respiration in isolated mitochondria. Isolation of mitochondria is not advantageous because it demands significant time and amount of tissue and, as tissue homogenates, disrupts biochemical and physical connections of mitochondria within the cell. Here, we described a new and efficient protocol to analyze the mitochondrial respiratory states in BAT biopsies that relies on intracellular triglyceride depletion followed by tissue permeabilization. In addition to minimizing tissue requirements to ∼17 mg wet weight, the proposed protocol enabled analysis of all mitochondrial respiratory states, including phosphorylation (OXPHOS), no-phosphorylation (LEAK), and uncoupled (ETS) states, as well as the use of substrates for complex I, complex II, and cytochrome c; together, these features demonstrated mitochondrial integrity and validated the preparation efficacy. Therefore, the protocol described here increases the possibilities of answering physiological questions related to small BAT regions of human and animal models, which shall help to unravel the mechanisms that regulate mitochondrial function in health and disease.", "title": "Triglyceride depletion of brown adipose tissue enables analysis of mitochondrial respiratory function in permeabilized biopsies." }, { "docid": "38023457", "text": "Severe quantitative and qualitative brown adipocyte defects are common in obesity. To investigate whether aberrant expression of tumor necrosis factor alpha (TNF-alpha) in obesity is involved in functional brown fat atrophy, we have studied genetically obese (ob/ob) mice with targeted null mutations in the genes encoding the two TNF receptors. The absence of both TNF receptors or p55 receptor alone resulted in a significant reduction in brown adipocyte apoptosis and an increase in beta(3)-adrenoreceptor and uncoupling protein-1 expression in obese mice. Increased numbers of multilocular functionally active brown adipocytes, and improved thermoregulation was also observed in obese animals lacking TNF-alpha function. These results indicate that TNF-alpha plays an important role in multiple aspects of brown adipose tissue biology and mediates the abnormalities that occur at this site in obesity.", "title": "Tumor necrosis factor alpha mediates apoptosis of brown adipocytes and defective brown adipocyte function in obesity." }, { "docid": "4854076", "text": "The rising incidence of obesity and associated metabolic diseases has increased the urgency in understanding all aspects of adipose tissue biology. This includes the function of adipocytes, how adipose tissue expands in obesity, and how expanded adipose tissues in adults can impact physiology. Here, we highlight the growing appreciation for the importance of de novo adipocyte differentiation to adipose tissue expansion in adult humans and animals. We detail recent efforts to identify adipose precursor populations that contribute to the physiological postnatal recruitment of white, brown, and beige adipocytes in mice, and summarize new data that reveal the complexity of adipose tissue development in vivo.", "title": "The expanding problem of adipose depot remodeling and postnatal adipocyte progenitor recruitment." }, { "docid": "11428884", "text": "Adipose tissue is an important metabolic organ, the dysfunction of which is associated with the development of obesity, diabetes mellitus, and cardiovascular disease. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is considered the master regulator of adipocyte differentiation and function. Although its cell-autonomous role in adipogenesis has been clearly demonstrated in cell culture, previous fat-specific knockouts of the murine PPARγ gene did not demonstrate a dramatic phenotype in vivo. Here, using Adipoq-Cre mice to drive adipose-specific recombination, we report a unique fat-specific PPARγ knockout (PPARγ FKO) mouse model with almost no visible brown and white adipose tissue at age 3 mo. As a consequence, PPARγ FKO mice had hugely enlarged pancreatic islets, massive fatty livers, and dramatically elevated levels of blood glucose and serum insulin accompanied by extreme insulin resistance. PPARγ FKO mice also exhibited delayed hair coat formation associated with absence of dermal fat, disrupted mammary gland development with loss of mammary fat pads, and high bone mass with loss of bone marrow fat, indicating the critical roles of adipose PPARγ in these tissues. Together, our data reveal the necessity of fat PPARγ in adipose formation, whole-body metabolic homeostasis, and normal development of fat-containing tissues.", "title": "Lipoatrophy and severe metabolic disturbance in mice with fat-specific deletion of PPARγ." }, { "docid": "1507222", "text": "Weight loss in cancer cachexia is attributable to decreased food intake and/or enhanced energy expenditure. We investigated the roles of the uncoupling proteins (UCPs) UCPI, -2, and -3 in a murine model of cachexia, the MAC16 adenocarcinoma. Weight fell to 24% below that of non-tumor-bearing controls (P < 0.01) 18 days after MAC16 inoculation, with significant reductions in fat-pad mass (-67%; P < 0.01) and muscle mass (-20%; P < 0.01). Food intake was 26-60% lower (P < 0.01) than in controls on days 17-18. Non-tumor-bearing mice, pair-fed to match MAC16-induced hypophagia, showed less weight loss (10% below controls, P < 0.01; 16% above MAC-16, P < 0.01) and smaller decreases in fat-pad mass (21% below controls, P < 0.01). Core temperature in MAC16 mice was significantly lower (-2.4 degrees C, P < 0.01) than in controls, and pair-feeding had no effect. MAC16 mice showed significantly higher UCP1 mRNA levels in brown adipose tissue (BAT) than in controls (+63%, P < 0.01), and pair-feeding had no effect. UCP2 and -3 expression in BAT did not differ significantly between groups. By contrast, UCP2 mRNA levels in skeletal muscle were comparably increased in both MAC16 and pair-fed groups (respectively, 183 and 163% above controls; both, P < 0.05), with no significant difference between these two groups. Similarly, UCP3 mRNA was significantly higher than controls in both MAC16 (+163%, P < 0.05) and pair-fed (+253%, P < 0.01) groups, with no significant difference between the two experimental groups. Overexpression of UCP1 in BAT in MAC16-bearing mice may be an adaptive response to hypothermia, which is apparently induced by tumor products; increased thermogenesis in BAT could increase total energy expenditure and, thus, contribute to tissue wasting. Increased UCP2 and -3 expression in muscle are both attributable to reduced food intake and may be involved in lipid utilization during lipolysis in MAC16-induced cachexia.", "title": "Increased gene expression of brown fat uncoupling protein (UCP)1 and skeletal muscle UCP2 and UCP3 in MAC16-induced cancer cachexia." }, { "docid": "34582256", "text": "The object of this study was to assess the role of brown adipose tissue (BAT) and the sympathetic nervous system in the rise in heat production associated with endotoxin-induced fever. Oxygen consumption (VO2) was found to be significantly increased (28%) over a 4-h period after two doses of endotoxin (Escherichia coli lipopolysaccharide, 0.3 mg/100 g body wt) given 24 h apart. Injection of a mixed beta-adrenoceptor antagonist (propranolol) reduced VO2 by 14% in endotoxin-treated rats, whereas the selective beta 1- (atenolol) or beta 2- (ICI 118551) antagonists suppressed VO2 by 10%. These drugs did not affect VO2 in control animals. BAT thermogenic activity assessed from measurements of in vitro mitochondrial guanosine 5'-diphosphate (GDP) binding was elevated by 54% in interscapular BAT and by 171% in other BAT depots. Surgical denervation of one lobe of the interscapular depot prevented these responses. Endotoxin failed to stimulate GDP binding in rats fed protein-deficient diets. This may have been because BAT thermogenic activity was already elevated in control rats fed these diets or because endotoxin caused a marked suppression of food intake in the protein-deficient animals. The results indicate that sympathetic activation of BAT is involved in the thermogenic responses to endotoxin and that these can be modified by dietary manipulation.", "title": "Involvement of sympathetic nervous system and brown fat in endotoxin-induced fever in rats." }, { "docid": "36889513", "text": "Bile acids regulate the transcription of genes that control cholesterol homeostasis through molecular mechanisms that are poorly understood. Physiological concentrations of free and conjugated chenodeoxycholic acid, lithocholic acid, and deoxycholic acid activated the farnesoid X receptor (FXR; NR1H4), an orphan nuclear receptor. As ligands, these bile acids and their conjugates modulated interaction of FXR with a peptide derived from steroid receptor coactivator 1. These results provide evidence for a nuclear bile acid signaling pathway that may regulate cholesterol homeostasis.", "title": "Bile acids: natural ligands for an orphan nuclear receptor." }, { "docid": "20532591", "text": "White adipose tissue displays high plasticity. We developed a system for the inducible, permanent labeling of mature adipocytes that we called the AdipoChaser mouse. We monitored adipogenesis during development, high-fat diet (HFD) feeding and cold exposure. During cold-induced 'browning' of subcutaneous fat, most 'beige' adipocytes stem from de novo–differentiated adipocytes. During HFD feeding, epididymal fat initiates adipogenesis after 4 weeks, whereas subcutaneous fat undergoes hypertrophy for a period of up to 12 weeks. Gonadal fat develops postnatally, whereas subcutaneous fat develops between embryonic days 14 and 18. Our results highlight the extensive differences in adipogenic potential in various fat depots.", "title": "Tracking adipogenesis during white adipose tissue development, expansion and regeneration" } ]

[ { "docid": "1568684", "text": "The interest in brown adipose tissue (BAT) as a target to combat metabolic disease has recently been renewed with the discovery of functional BAT in humans. In rodents, BAT can be activated by bile acids, which activate type 2 iodothyronine deiodinase (D2) in BAT via the G-coupled protein receptor TGR5, resulting in increased oxygen consumption and energy expenditure. Here we examined the effects of oral supplementation of the bile acid chenodeoxycholic acid (CDCA) on human BAT activity. Treatment of 12 healthy female subjects with CDCA for 2 days resulted in increased BAT activity. Whole-body energy expenditure was also increased upon CDCA treatment. In vitro treatment of primary human brown adipocytes derived with CDCA or specific TGR5 agonists increased mitochondrial uncoupling and D2 expression, an effect that was absent in human primary white adipocytes. These findings identify bile acids as a target to activate BAT in humans.", "title": "The Bile Acid Chenodeoxycholic Acid Increases Human Brown Adipose Tissue Activity." } ]

[ { "docid": "4319174", "text": "All homeotherms use thermogenesis to maintain their core body temperature, ensuring that cellular functions and physiological processes can continue in cold environments. In the prevailing model of thermogenesis, when the hypothalamus senses cold temperatures it triggers sympathetic discharge, resulting in the release of noradrenaline in brown adipose tissue and white adipose tissue. Acting via the β(3)-adrenergic receptors, noradrenaline induces lipolysis in white adipocytes, whereas it stimulates the expression of thermogenic genes, such as PPAR-γ coactivator 1a (Ppargc1a), uncoupling protein 1 (Ucp1) and acyl-CoA synthetase long-chain family member 1 (Acsl1), in brown adipocytes. However, the precise nature of all the cell types involved in this efferent loop is not well established. Here we report in mice an unexpected requirement for the interleukin-4 (IL-4)-stimulated program of alternative macrophage activation in adaptive thermogenesis. Exposure to cold temperature rapidly promoted alternative activation of adipose tissue macrophages, which secrete catecholamines to induce thermogenic gene expression in brown adipose tissue and lipolysis in white adipose tissue. Absence of alternatively activated macrophages impaired metabolic adaptations to cold, whereas administration of IL-4 increased thermogenic gene expression, fatty acid mobilization and energy expenditure, all in a macrophage-dependent manner. Thus, we have discovered a role for alternatively activated macrophages in the orchestration of an important mammalian stress response, the response to cold.", "title": "Alternatively activated macrophages produce catecholamines to sustain adaptive thermogenesis" }, { "docid": "14865329", "text": "Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders.", "title": "Brown Fat and Browning for the Treatment of Obesity and Related Metabolic Disorders" }, { "docid": "29691654", "text": "Until recently, the mechanism of adaptive thermogenesis was ascribed to the expression of uncoupling protein 1 (UCP1) in brown and beige adipocytes. UCP1 is known to catalyze a proton leak of the inner mitochondrial membrane, resulting in uncoupled oxidative metabolism with no production of adenosine triphosphate and increased energy expenditure. Thus increasing brown and beige adipose tissue with augmented UCP1 expression is a viable target for obesity-related disorders. Recent work demonstrates an UCP1-independent pathway to uncouple mitochondrial respiration. A secreted enzyme, PM20D1, enriched in UCP1+ adipocytes, exhibits catalytic and hydrolytic activity to reversibly form N-acyl amino acids. N-acyl amino acids act as endogenous uncouplers of mitochondrial respiration at physiological concentrations. Administration of PM20D1 or its products, N-acyl amino acids, to diet-induced obese mice improves glucose tolerance by increasing energy expenditure. In short-term studies, treated animals exhibit no toxicity while experiencing 10% weight loss primarily of adipose tissue. Further study of this metabolic pathway may identify novel therapies for diabesity, the disease state associated with diabetes and obesity.", "title": "Uncoupling Mitochondrial Respiration for Diabesity." }, { "docid": "29381091", "text": "Brown adipocytes dissipate energy, whereas white adipocytes are an energy storage site. We explored the plasticity of different white adipose tissue depots in acquiring a brown phenotype by cold exposure. By comparing cold-induced genes in white fat to those enriched in brown compared with white fat, at thermoneutrality we defined a \"brite\" transcription signature. We identified the genes, pathways, and promoter regulatory motifs associated with \"browning,\" as these represent novel targets for understanding this process. For example, neuregulin 4 was more highly expressed in brown adipose tissue and upregulated in white fat upon cold exposure, and cell studies showed that it is a neurite outgrowth-promoting adipokine, indicative of a role in increasing adipose tissue innervation in response to cold. A cell culture system that allows us to reproduce the differential properties of the discrete adipose depots was developed to study depot-specific differences at an in vitro level. The key transcriptional events underpinning white adipose tissue to brown transition are important, as they represent an attractive proposition to overcome the detrimental effects associated with metabolic disorders, including obesity and type 2 diabetes.", "title": "Brown and white adipose tissues: intrinsic differences in gene expression and response to cold exposure in mice" }, { "docid": "52865789", "text": "OBJECTIVE IL-15 is an inflammatory cytokine secreted by many cell types. IL-15 is also produced during physical exercise by skeletal muscle and has been reported to reduce weight gain in mice. Contrarily, our findings on IL-15 knockout (KO) mice indicate that IL-15 promotes obesity. The aim of this study is to investigate the mechanisms underlying the pro-obesity role of IL-15 in adipose tissues. \n METHODS Control and IL-15 KO mice were maintained on high fat diet (HFD) or normal control diet. After 16 weeks, body weight, adipose tissue and skeletal mass, serum lipid levels and gene/protein expression in the adipose tissues were evaluated. The effect of IL-15 on thermogenesis and oxygen consumption was also studied in primary cultures of adipocytes differentiated from mouse preadipocyte and human stem cells. \n RESULTS Our results show that IL-15 deficiency prevents diet-induced weight gain and accumulation of lipids in visceral and subcutaneous white and brown adipose tissues. Gene expression analysis also revealed elevated expression of genes associated with adaptive thermogenesis in the brown and subcutaneous adipose tissues of IL-15 KO mice. Accordingly, oxygen consumption was increased in the brown adipocytes from IL-15 KO mice. In addition, IL-15 KO mice showed decreased expression of pro-inflammatory mediators in their adipose tissues. \n CONCLUSIONS Absence of IL-15 results in decreased accumulation of fat in the white adipose tissues and increased lipid utilization via adaptive thermogenesis. IL-15 also promotes inflammation in adipose tissues that could sustain chronic inflammation leading to obesity-associated metabolic syndrome.", "title": "Deficiency of Interleukin-15 Confers Resistance to Obesity by Diminishing Inflammation and Enhancing the Thermogenic Function of Adipose Tissues" }, { "docid": "26902591", "text": "Cancer-associated cachexia (CAC) is a wasting syndrome characterized by systemic inflammation, body weight loss, atrophy of white adipose tissue (WAT) and skeletal muscle. Limited therapeutic options are available and the underlying mechanisms are poorly defined. Here we show that a phenotypic switch from WAT to brown fat, a phenomenon termed WAT browning, takes place in the initial stages of CAC, before skeletal muscle atrophy. WAT browning is associated with increased expression of uncoupling protein 1 (UCP1), which uncouples mitochondrial respiration toward thermogenesis instead of ATP synthesis, leading to increased lipid mobilization and energy expenditure in cachectic mice. Chronic inflammation and the cytokine interleukin-6 increase UCP1 expression in WAT, and treatments that reduce inflammation or β-adrenergic blockade reduce WAT browning and ameliorate the severity of cachexia. Importantly, UCP1 staining is observed in WAT from CAC patients. Thus, inhibition of WAT browning represents a promising approach to ameliorate cachexia in cancer patients.", "title": "A switch from white to brown fat increases energy expenditure in cancer-associated cachexia." }, { "docid": "38023457", "text": "Severe quantitative and qualitative brown adipocyte defects are common in obesity. To investigate whether aberrant expression of tumor necrosis factor alpha (TNF-alpha) in obesity is involved in functional brown fat atrophy, we have studied genetically obese (ob/ob) mice with targeted null mutations in the genes encoding the two TNF receptors. The absence of both TNF receptors or p55 receptor alone resulted in a significant reduction in brown adipocyte apoptosis and an increase in beta(3)-adrenoreceptor and uncoupling protein-1 expression in obese mice. Increased numbers of multilocular functionally active brown adipocytes, and improved thermoregulation was also observed in obese animals lacking TNF-alpha function. These results indicate that TNF-alpha plays an important role in multiple aspects of brown adipose tissue biology and mediates the abnormalities that occur at this site in obesity.", "title": "Tumor necrosis factor alpha mediates apoptosis of brown adipocytes and defective brown adipocyte function in obesity." }, { "docid": "2605032", "text": "We investigated if whether intrauterine protein restriction in combination with overfeeding during lactation would cause adult-onset obesity and metabolic disorders. After birth, litters from dams fed with control (17% protein) and low protein (6% protein) diets were adjusted to a size of four (CO and LO groups, respectively) or eight (CC and LC groups, respectively) pups. All of the offspring were fed a diet containing 12% protein from the time of weaning until they were 90 d old. Compared to the CC and LC groups, the CO and LO groups had higher relative and absolute food intakes, oxygen consumption and carbon dioxide production; lower brown adipose tissue weight and lipid content and greater weight gain and absolute and relative white adipose tissue weight and absolute lipid content. Compared with the CO and CC rats, the LC and LO rats exhibited higher relative food intake, brown adipose tissue weight and lipid content, reduced oxygen consumption, carbon dioxide production and spontaneous activity, increased relative retroperitoneal adipose tissue weight and unaltered absolute white adipose tissue weight and lipid content. The fasting serum glucose was similar among the groups. The area under the glucose curve was higher in the LO and CO rats than in the LC and CC rats. The basal insulinemia and homeostasis model assessment of insulin resistance (HOMA-IR) were lower in the LO group than in the other groups. The total area under the insulin curve for the LO rats was similar to the CC rats, and both were lower than the CO and LC rats. Kitt was higher in the LO, LC and CO groups than in the CC group. Thus, intrauterine protein restriction followed by overfeeding during lactation did not induce obesity, but produced glucose intolerance by impairing pancreatic function in adulthood.", "title": "Intrauterine protein restriction combined with early postnatal overfeeding was not associated with adult-onset obesity but produced glucose intolerance by pancreatic dysfunction" }, { "docid": "40232172", "text": "The research on mitochondrial functions in adipocytes has increasingly evidenced that mitochondria plays an important role in the onset and/or progression of obesity and related pathologies. Mitochondrial function in brown adipose tissue (BAT) has been classically assessed by measuring either the levels/activity of mitochondrial enzymes, or the respiration in isolated mitochondria. Isolation of mitochondria is not advantageous because it demands significant time and amount of tissue and, as tissue homogenates, disrupts biochemical and physical connections of mitochondria within the cell. Here, we described a new and efficient protocol to analyze the mitochondrial respiratory states in BAT biopsies that relies on intracellular triglyceride depletion followed by tissue permeabilization. In addition to minimizing tissue requirements to ∼17 mg wet weight, the proposed protocol enabled analysis of all mitochondrial respiratory states, including phosphorylation (OXPHOS), no-phosphorylation (LEAK), and uncoupled (ETS) states, as well as the use of substrates for complex I, complex II, and cytochrome c; together, these features demonstrated mitochondrial integrity and validated the preparation efficacy. Therefore, the protocol described here increases the possibilities of answering physiological questions related to small BAT regions of human and animal models, which shall help to unravel the mechanisms that regulate mitochondrial function in health and disease.", "title": "Triglyceride depletion of brown adipose tissue enables analysis of mitochondrial respiratory function in permeabilized biopsies." }, { "docid": "4854076", "text": "The rising incidence of obesity and associated metabolic diseases has increased the urgency in understanding all aspects of adipose tissue biology. This includes the function of adipocytes, how adipose tissue expands in obesity, and how expanded adipose tissues in adults can impact physiology. Here, we highlight the growing appreciation for the importance of de novo adipocyte differentiation to adipose tissue expansion in adult humans and animals. We detail recent efforts to identify adipose precursor populations that contribute to the physiological postnatal recruitment of white, brown, and beige adipocytes in mice, and summarize new data that reveal the complexity of adipose tissue development in vivo.", "title": "The expanding problem of adipose depot remodeling and postnatal adipocyte progenitor recruitment." }, { "docid": "36838958", "text": "Uncoupling protein 1 (Ucp1), which is localized in the mitochondrial inner membrane of mammalian brown adipose tissue (BAT), generates heat by uncoupling oxidative phosphorylation. Upon cold exposure or nutritional abundance, sympathetic neurons stimulate BAT to express Ucp1 to induce energy dissipation and thermogenesis. Accordingly, increased Ucp1 expression reduces obesity in mice and is correlated with leanness in humans. Despite this significance, there is currently a limited understanding of how Ucp1 expression is physiologically regulated at the molecular level. Here, we describe the involvement of Sestrin2 and reactive oxygen species (ROS) in regulation of Ucp1 expression. Transgenic overexpression of Sestrin2 in adipose tissues inhibited both basal and cold-induced Ucp1 expression in interscapular BAT, culminating in decreased thermogenesis and increased fat accumulation. Endogenous Sestrin2 is also important for suppressing Ucp1 expression because BAT from Sestrin2(-/-) mice exhibited a highly elevated level of Ucp1 expression. The redox-inactive mutant of Sestrin2 was incapable of regulating Ucp1 expression, suggesting that Sestrin2 inhibits Ucp1 expression primarily through reducing ROS accumulation. Consistently, ROS-suppressing antioxidant chemicals, such as butylated hydroxyanisole and N-acetylcysteine, inhibited cold- or cAMP-induced Ucp1 expression as well. p38 MAPK, a signaling mediator required for cAMP-induced Ucp1 expression, was inhibited by either Sestrin2 overexpression or antioxidant treatments. Taken together, these results suggest that Sestrin2 and antioxidants inhibit Ucp1 expression through suppressing ROS-mediated p38 MAPK activation, implying a critical role of ROS in proper BAT metabolism.", "title": "Sestrin2 inhibits uncoupling protein 1 expression through suppressing reactive oxygen species." }, { "docid": "3621011", "text": "Proper regulation of energy storage in adipose tissue is crucial for maintaining insulin sensitivity and molecules contributing to this process have not been fully revealed. Here we show that type II transmembrane protein tenomodulin (TNMD) is upregulated in adipose tissue of insulin-resistant versus insulin-sensitive individuals, who were matched for body mass index (BMI). TNMD expression increases in human preadipocytes during differentiation, whereas silencing TNMD blocks adipogenesis. Upon high-fat diet feeding, transgenic mice overexpressing Tnmd develop increased epididymal white adipose tissue (eWAT) mass, and preadipocytes derived from Tnmd transgenic mice display greater proliferation, consistent with elevated adipogenesis. In Tnmd transgenic mice, lipogenic genes are upregulated in eWAT, as is Ucp1 in brown fat, while liver triglyceride accumulation is attenuated. Despite expanded eWAT, transgenic animals display improved systemic insulin sensitivity, decreased collagen deposition and inflammation in eWAT, and increased insulin stimulation of Akt phosphorylation. Our data suggest that TNMD acts as a protective factor in visceral adipose tissue to alleviate insulin resistance in obesity.", "title": "Tenomodulin promotes human adipocyte differentiation and beneficial visceral adipose tissue expansion." }, { "docid": "17973161", "text": "Uncoupling protein 1 (UCP1) is highly expressed in brown adipose tissue, where it generates heat by uncoupling electron transport from ATP production. UCP1 is also found outside classical brown adipose tissue depots, in adipocytes that are termed 'brite' (brown-in-white) or 'beige'. In humans, the presence of brite or beige (brite/beige) adipocytes is correlated with a lean, metabolically healthy phenotype, but whether a causal relationship exists is not clear. Here we report that human brite/beige adipocyte progenitors proliferate in response to pro-angiogenic factors, in association with expanding capillary networks. Adipocytes formed from these progenitors transform in response to adenylate cyclase activation from being UCP1 negative to being UCP1 positive, which is a defining feature of the beige/brite phenotype, while displaying uncoupled respiration. When implanted into normal chow-fed, or into high-fat diet (HFD)-fed, glucose-intolerant NOD-scid IL2rg(null) (NSG) mice, brite/beige adipocytes activated in vitro enhance systemic glucose tolerance. These adipocytes express neuroendocrine and secreted factors, including the pro-protein convertase PCSK1, which is strongly associated with human obesity. Pro-angiogenic conditions therefore drive the proliferation of human beige/brite adipocyte progenitors, and activated beige/brite adipocytes can affect systemic glucose homeostasis, potentially through a neuroendocrine mechanism.", "title": "Human ‘brite / beige’ adipocytes develop from capillary networks and their implantation improves metabolic homeostasis in mice" }, { "docid": "6227220", "text": "Despite growing interest and a recent surge in papers, the role of autophagy in glucose and lipid metabolism is unclear. We produced mice with skeletal muscle–specific deletion of Atg7 (encoding autophagy-related 7). Unexpectedly, these mice showed decreased fat mass and were protected from diet-induced obesity and insulin resistance; this phenotype was accompanied by increased fatty acid oxidation and browning of white adipose tissue (WAT) owing to induction of fibroblast growth factor 21 (Fgf21). Mitochondrial dysfunction induced by autophagy deficiency increased Fgf21 expression through induction of Atf4, a master regulator of the integrated stress response. Mitochondrial respiratory chain inhibitors also induced Fgf21 in an Atf4-dependent manner. We also observed induction of Fgf21, resistance to diet-induced obesity and amelioration of insulin resistance in mice with autophagy deficiency in the liver, another insulin target tissue. These findings suggest that autophagy deficiency and subsequent mitochondrial dysfunction promote Fgf21 expression, a hormone we consequently term a 'mitokine', and together these processes promote protection from diet-induced obesity and insulin resistance.", "title": "Autophagy deficiency leads to protection from obesity and insulin resistance by inducing Fgf21 as a mitokine" }, { "docid": "11428884", "text": "Adipose tissue is an important metabolic organ, the dysfunction of which is associated with the development of obesity, diabetes mellitus, and cardiovascular disease. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is considered the master regulator of adipocyte differentiation and function. Although its cell-autonomous role in adipogenesis has been clearly demonstrated in cell culture, previous fat-specific knockouts of the murine PPARγ gene did not demonstrate a dramatic phenotype in vivo. Here, using Adipoq-Cre mice to drive adipose-specific recombination, we report a unique fat-specific PPARγ knockout (PPARγ FKO) mouse model with almost no visible brown and white adipose tissue at age 3 mo. As a consequence, PPARγ FKO mice had hugely enlarged pancreatic islets, massive fatty livers, and dramatically elevated levels of blood glucose and serum insulin accompanied by extreme insulin resistance. PPARγ FKO mice also exhibited delayed hair coat formation associated with absence of dermal fat, disrupted mammary gland development with loss of mammary fat pads, and high bone mass with loss of bone marrow fat, indicating the critical roles of adipose PPARγ in these tissues. Together, our data reveal the necessity of fat PPARγ in adipose formation, whole-body metabolic homeostasis, and normal development of fat-containing tissues.", "title": "Lipoatrophy and severe metabolic disturbance in mice with fat-specific deletion of PPARγ." }, { "docid": "34582256", "text": "The object of this study was to assess the role of brown adipose tissue (BAT) and the sympathetic nervous system in the rise in heat production associated with endotoxin-induced fever. Oxygen consumption (VO2) was found to be significantly increased (28%) over a 4-h period after two doses of endotoxin (Escherichia coli lipopolysaccharide, 0.3 mg/100 g body wt) given 24 h apart. Injection of a mixed beta-adrenoceptor antagonist (propranolol) reduced VO2 by 14% in endotoxin-treated rats, whereas the selective beta 1- (atenolol) or beta 2- (ICI 118551) antagonists suppressed VO2 by 10%. These drugs did not affect VO2 in control animals. BAT thermogenic activity assessed from measurements of in vitro mitochondrial guanosine 5'-diphosphate (GDP) binding was elevated by 54% in interscapular BAT and by 171% in other BAT depots. Surgical denervation of one lobe of the interscapular depot prevented these responses. Endotoxin failed to stimulate GDP binding in rats fed protein-deficient diets. This may have been because BAT thermogenic activity was already elevated in control rats fed these diets or because endotoxin caused a marked suppression of food intake in the protein-deficient animals. The results indicate that sympathetic activation of BAT is involved in the thermogenic responses to endotoxin and that these can be modified by dietary manipulation.", "title": "Involvement of sympathetic nervous system and brown fat in endotoxin-induced fever in rats." }, { "docid": "25687558", "text": "The genetically obese (ob/ob) mouse exhibits defective thermoregulatory responses to cold exposure. Pathophysiological explanations for this phenomenon have focused on abnormalities in intracellular metabolism or insensitivity of peripheral tissues to the thermogenic effects of catecholamines. Because the sympathetic nervous system (SNS) is subject to feedback regulation, a peripheral impairment in thermogenesis should be associated with a compensatory increase in SNS activity. To examine SNS activity in the ob/ob mouse, norepinephrine (NE) turnover was measured in heart and interscapular brown adipose tissue (IBAT) of ob/ob and lean mice. The results from studies utilizing radiolabeled NE or inhibition of NE biosynthesis with alpha-methyl-p-tyrosine to measure NE turnover demonstrated reductions in SNS activity of 33-56% in heart and of 45-73% in IBAT in ob/ob mice at ambient temperature (22 degrees C) compared with measurements in lean controls. During cold exposure (4 degrees C) NE turnover increased in heart and IBAT to a similar extent in both ob/ob and lean mice, but NE turnover rates in heart, and probably in IBAT as well, remained lower in the obese mice than in the lean despite the gradual development of hypothermia in the ob/ob mice during this period. Administration of naltrexone, a long-acting opiate antagonist, failed to reverse the suppression of SNS activity observed in the ob/ob mice. These data indicate that diminished SNS activity in ob/ob mice may be an additional factor contributing to the defective thermogenesis characteristic of these animals.", "title": "Diminished sympathetic nervous system activity in genetically obese (ob/ob) mouse." }, { "docid": "20363389", "text": "In order to elucidate energy balance in the skeletal muscle, we cloned cDNA of a homologue of uncoupling protein (UCP) from rat skeletal muscle. We also cloned rat UCP-2 cDNA from rat brown adipose tissue (BAT). The UCP cloned from rat skeletal muscle showed 57% and 72% identity with rat UCP-1 and UCP-2. The mRNA was expressed abundantly in the skeletal muscle, moderately in the BAT, and slightly in the white adipose tissue (WAT) with a major band at 2.5 kb and a minor band at 2.8 kb, while the UCP-2 gene expression was widely detected in the whole body with substantial levels in the WAT and with slight levels in the skeletal muscle and BAT. The rat UCP cloned in the present study showed 86% identity with the recently cloned human UCP-3, which was also expressed abundantly in the skeletal muscle with a signal of 2.4 kb. Therefore, the rat UCP was considered to be rat UCP-3. In rats fed high-fat diet the UCP-3 gene expression was augmented 2-fold in the skeletal muscle while UCP-2 mRNA levels were increased significantly (1.6-fold) in the epididymal WAT. Augmented expression of UCPs may provide defense against high-fat induced obesity and impairment of glucose metabolism.", "title": "Cloning of rat uncoupling protein-3 and uncoupling protein-2 cDNAs: their gene expression in rats fed high-fat diet." }, { "docid": "1507222", "text": "Weight loss in cancer cachexia is attributable to decreased food intake and/or enhanced energy expenditure. We investigated the roles of the uncoupling proteins (UCPs) UCPI, -2, and -3 in a murine model of cachexia, the MAC16 adenocarcinoma. Weight fell to 24% below that of non-tumor-bearing controls (P < 0.01) 18 days after MAC16 inoculation, with significant reductions in fat-pad mass (-67%; P < 0.01) and muscle mass (-20%; P < 0.01). Food intake was 26-60% lower (P < 0.01) than in controls on days 17-18. Non-tumor-bearing mice, pair-fed to match MAC16-induced hypophagia, showed less weight loss (10% below controls, P < 0.01; 16% above MAC-16, P < 0.01) and smaller decreases in fat-pad mass (21% below controls, P < 0.01). Core temperature in MAC16 mice was significantly lower (-2.4 degrees C, P < 0.01) than in controls, and pair-feeding had no effect. MAC16 mice showed significantly higher UCP1 mRNA levels in brown adipose tissue (BAT) than in controls (+63%, P < 0.01), and pair-feeding had no effect. UCP2 and -3 expression in BAT did not differ significantly between groups. By contrast, UCP2 mRNA levels in skeletal muscle were comparably increased in both MAC16 and pair-fed groups (respectively, 183 and 163% above controls; both, P < 0.05), with no significant difference between these two groups. Similarly, UCP3 mRNA was significantly higher than controls in both MAC16 (+163%, P < 0.05) and pair-fed (+253%, P < 0.01) groups, with no significant difference between the two experimental groups. Overexpression of UCP1 in BAT in MAC16-bearing mice may be an adaptive response to hypothermia, which is apparently induced by tumor products; increased thermogenesis in BAT could increase total energy expenditure and, thus, contribute to tissue wasting. Increased UCP2 and -3 expression in muscle are both attributable to reduced food intake and may be involved in lipid utilization during lipolysis in MAC16-induced cachexia.", "title": "Increased gene expression of brown fat uncoupling protein (UCP)1 and skeletal muscle UCP2 and UCP3 in MAC16-induced cancer cachexia." } ]

[ { "docid": "37424881", "text": "OBJECTIVE Folate and vitamin B12 are two vital regulators in the metabolic process of homocysteine, which is a risk factor of atherothrombotic events. Low folate intake or low plasma folate concentration is associated with increased stroke risk. Previous randomized controlled trials presented discordant findings in the effect of folic acid supplementation-based homocysteine lowering on stroke risk. The aim of the present review was to perform a meta-analysis of relevant randomized controlled trials to check the how different folate fortification status might affect the effects of folic acid supplementation in lowering homocysteine and reducing stroke risk. \n DESIGN Relevant randomized controlled trials were identified through formal literature search. Homocysteine reduction was compared in subgroups stratified by folate fortification status. Relative risks with 95 % confidence intervals were used as a measure to assess the association between folic acid supplementation and stroke risk. \n SETTING The meta-analysis included fourteen randomized controlled trials, SUBJECTS A total of 39 420 patients. \n RESULTS Homocysteine reductions were 26·99 (sd 1·91) %, 18·38 (sd 3·82) % and 21·30 (sd 1·98) %, respectively, in the subgroups without folate fortification, with folate fortification and with partial folate fortification. Significant difference was observed between the subgroups with folate fortification and without folate fortification (P=0·05). The relative risk of stroke was 0·88 (95 % CI 0·77, 1·00, P=0·05) in the subgroup without folate fortification, 0·94 (95 % CI 0·58, 1·54, P=0·82) in the subgroup with folate fortification and 0·91 (95 % CI 0·82, 1·01, P=0·09) in the subgroup with partial folate fortification. \n CONCLUSIONS Folic acid supplementation might have a modest benefit on stroke prevention in regions without folate fortification.", "title": "The effect of folate fortification on folic acid-based homocysteine-lowering intervention and stroke risk: a meta-analysis." } ]

[ { "docid": "42441846", "text": "INTRODUCTION Elevated plasma total homocysteine is a major risk for coronary artery disease (CAD). Methyltetrahydrofolate reductase (MTHFR) is a main regulatory enzyme in homocysteine metabolism; a common C677T mutation in the MTHFR gene results in decreased enzyme activity, and contributes to increased homocysteine levels and decreased folate levels. We investigated the frequency of MTHFR C677T alleles in a Korean population, determined the genotype-specific threshold levels of folate or vitamin B12, and investigated the relationship between the TT genotype and the risk of CAD. MATERIALS AND METHODS We enrolled a study population of 163 CAD patients and 50 control subjects, and screened the MTHFR C677T polymorphism using real-time PCR with melting point analysis. Levels of plasma homocysteine, folate and vitamin B12 were also determined. We then defined the genotype-specific threshold values of folate and vitamin B12 required to keep homocysteine levels in a normal range for individuals of each MTHFR C677T genotype. \n RESULTS The frequency of the TT genotype was 18% in control subjects and 26% in patients group (P>0.05). Individuals homozygous for the TT genotype had significantly elevated homocysteine levels (P<0.05). The genotype-specific folate threshold level was significantly higher in TT individuals than in the CC or CT genotypes. The OR of individuals with low folate status and the TT genotype to estimate the relative risk of CAD was 2.2 and the OR of those with high folate status and the TT genotype was 1.5 (95% CI, 0.5-9.6 and 0.7-3.2, respectively). \n CONCLUSION We were able to define a gene-nutrient interaction that shows a higher risk for CAD based on specific threshold folate levels required by different MTHFR C677T genotypes in a Korean population.", "title": "Gene--nutrition interactions in coronary artery disease: correlation between the MTHFR C677T polymorphism and folate and homocysteine status in a Korean population." }, { "docid": "8595678", "text": "BACKGROUND The MTHFR 677C→T polymorphism has been associated with raised homocysteine concentration and increased risk of stroke. A previous overview showed that the effects were greatest in regions with low dietary folate consumption, but differentiation between the effect of folate and small-study bias was difficult. A meta-analysis of randomised trials of homocysteine-lowering interventions showed no reduction in coronary heart disease events or stroke, but the trials were generally set in populations with high folate consumption. We aimed to reduce the effect of small-study bias and investigate whether folate status modifies the association between MTHFR 677C→T and stroke in a genetic analysis and meta-analysis of randomised controlled trials. \n METHODS We established a collaboration of genetic studies consisting of 237 datasets including 59,995 individuals with data for homocysteine and 20,885 stroke events. We compared the genetic findings with a meta-analysis of 13 randomised trials of homocysteine-lowering treatments and stroke risk (45,549 individuals, 2314 stroke events, 269 transient ischaemic attacks). \n FINDINGS The effect of the MTHFR 677C→T variant on homocysteine concentration was larger in low folate regions (Asia; difference between individuals with TT versus CC genotype, 3·12 μmol/L, 95% CI 2·23 to 4·01) than in areas with folate fortification (America, Australia, and New Zealand, high; 0·13 μmol/L, -0·85 to 1·11). The odds ratio (OR) for stroke was also higher in Asia (1·68, 95% CI 1·44 to 1·97) than in America, Australia, and New Zealand, high (1·03, 0·84 to 1·25). Most randomised trials took place in regions with high or increasing population folate concentrations. The summary relative risk (RR) of stroke in trials of homocysteine-lowering interventions (0·94, 95% CI 0·85 to 1·04) was similar to that predicted for the same extent of homocysteine reduction in large genetic studies in populations with similar folate status (predicted RR 1·00, 95% CI 0·90 to 1·11). Although the predicted effect of homocysteine reduction from large genetic studies in low folate regions (Asia) was larger (RR 0·78, 95% CI 0·68 to 0·90), no trial has evaluated the effect of lowering of homocysteine on stroke risk exclusively in a low folate region. \n INTERPRETATION In regions with increasing levels or established policies of population folate supplementation, evidence from genetic studies and randomised trials is concordant in suggesting an absence of benefit from lowering of homocysteine for prevention of stroke. Further large-scale genetic studies of the association between MTHFR 677C→T and stroke in low folate settings are needed to distinguish effect modification by folate from small-study bias. If future randomised trials of homocysteine-lowering interventions for stroke prevention are undertaken, they should take place in regions with low folate consumption. \n FUNDING Full funding sources listed at end of paper (see Acknowledgments).", "title": "Effect modification by population dietary folate on the association between MTHFR genotype, homocysteine, and stroke risk: a meta-analysis of genetic studies and randomised trials" }, { "docid": "12810152", "text": "CONTEXT Hyperhomocysteinemia is caused by genetic and lifestyle influences, including low intakes of folate and vitamin B6. However, prospective data relating intake of these vitamins to risk of coronary heart disease (CHD) are not available. \n OBJECTIVE To examine intakes of folate and vitamin B6 in relation to the incidence of nonfatal myocardial infarction (MI) and fatal CHD. \n DESIGN Prospective cohort study. \n SETTING AND PATIENTS In 1980, a total of 80082 women from the Nurses' Health Study with no previous history of cardiovascular disease, cancer, hypercholesterolemia, or diabetes completed a detailed food frequency questionnaire from which we derived usual intake of folate and vitamin B6. \n MAIN OUTCOME MEASURE Nonfatal MI and fatal CHD confirmed by World Health Organization criteria. \n RESULTS During 14 years of follow-up, we documented 658 incident cases of nonfatal MI and 281 cases of fatal CHD. After controlling for cardiovascular risk factors, including smoking and hypertension and intake of alcohol, fiber, vitamin E, and saturated, polyunsaturated, and trans fat, the relative risks (RRs) of CHD between extreme quintiles were 0.69 (95% confidence interval [CI], 0.55-0.87) for folate (median intake, 696 microg/d vs 158 microg/d) and 0.67 (95% CI, 0.53-0.85) for vitamin B6 (median intake, 4.6 mg/d vs 1.1 mg/d). Controlling for the same variables, the RR was 0.55 (95% CI, 0.41-0.74) among women in the highest quintile of both folate and vitamin B6 intake compared with the opposite extreme. Risk of CHD was reduced among women who regularly used multiple vitamins (RR=0.76; 95% CI, 0.65-0.90), the major source of folate and vitamin B6, and after excluding multiple vitamin users, among those with higher dietary intakes of folate and vitamin B6. In a subgroup analysis, compared with nondrinkers, the inverse association between a high-folate diet and CHD was strongest among women who consumed up to 1 alcoholic beverage per day (RR =0.69; 95% CI, 0.49-0.97) or more than 1 drink per day (RR=0.27; 95% CI, 0.13-0.58). \n CONCLUSION These results suggest that intake of folate and vitamin B6 above the current recommended dietary allowance may be important in the primary prevention of CHD among women.", "title": "Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women." }, { "docid": "2647374", "text": "INTRODUCTION Deregulated or excessive host immune responses contribute to the pathogenesis of sepsis. Toll-like receptor (TLR) signaling pathways and their negative regulators play a pivotal role in the modulation of host immune responses and the development of sepsis. The objective of this study was to investigate the association of variants in the TLR signaling pathway genes and their negative regulator genes with susceptibility to sepsis in the Chinese Han population. \n METHODS Patients with severe sepsis (n = 378) and healthy control subjects (n = 390) were enrolled. Five genes, namely TLR2, TLR4, TLR9, MyD88 and TOLLIP, were investigated for their association with sepsis susceptibility by a tag single nucleotide polymorphism (SNP) strategy. Twelve tag SNPs were selected based on the data of Chinese Han in Beijing from the HapMap project and genotyped by direct sequencing. The mRNA expression levels of TOLLIP were determined using real-time quantitative Polymerase Chain Reaction (PCR) assays, and concentrations of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay (ELISA). \n RESULTS Our results showed that the minor C-allele of rs5743867 in TOLLIP was significantly associated with the decreased risk of sepsis (Padj = 0.00062, odds ratio (OR)adj = 0.71, 95% confidence interval (CI) 0.59 to 0.86) after adjustment for covariates in multiple logistic regression analysis. A 3-SNP haplotype block harboring the associated SNP rs5743867 also displayed strong association with omnibus test P value of 0.00049. Haplotype GTC showed a protective role against sepsis (Padj = 0.0012), while haplotype GCT showed an increased risk for sepsis (Padj = 0.00092). After exposure to lipopolysaccharide (LPS), TOLLIP mRNA expression levels in peripheral blood mononuclear cells (PBMCs) from homozygotes for the rs5743867C allele were significantly higher than in heterozygotes and homozygotes for the rs5743867T allele (P = 0.013 and P = 0.01, respectively). Moreover, the concentrations of TNF-α and IL-6 in culture supernatants were significantly lower in the subjects of rs5743867CC genotype than in CT and TT genotype subjects (P = 0.016 and P = 0.003 for TNF-α; P = 0.01 and P = 0.002 for IL-6, respectively). \n CONCLUSIONS Our findings indicated that the variants in TOLLIP were significantly associated with sepsis susceptibility in the Chinese Han population.", "title": "Variants in the Toll-interacting protein gene are associated with susceptibility to sepsis in the Chinese Han population" }, { "docid": "18557974", "text": "High plasma total homocysteine (tHcy) concentration is reported to be a risk factor for vascular diseases. We investigated the extent to which serum folate and plasma tHcy respond to a high intake of natural folate from food. Thirty-seven healthy females volunteered t o participate in a crossover dietary intervention. The study included a baseline period and two 5-week diet periods (low- and high-folate diets) with a 3-week washout in between. The low-folate diet contained one serving of both vegetables and fruit/d, while during the high-folate diet the subjects ate at least seven servings of vegetables, berries, and citrus fruit/d. Serum and erythrocyte (RBC) folate, serum vitamin B (12), and plasma tHcy concentrations were measured at the base-line and at the end of each diet period. The mean concentrations of serum and RBC folate were 11.0 (SD 3.0) nmol/l and 412 (SD 120) nmol/l at the end of the low-folate diet and 78 (95 % CI 62, 94) % and 14 (95 % CI 8, 20) % higher in response to the high-folate diet (P< 0.001). The serum concentration of vitamin B12 remained unchanged during the intervention. The mean plasma tHcy concentration was 8.0 pmol/ at the end of the low-folate diet and decreased by 13 (95% CI 9, 18) % in response to the high-folate diet (P<0.001). In conclusion, a diet high in fresh berries, citrus fruit, and vegetables effectively increases serum and RBC folate and decreases plasma homocysteine.", "title": "British Journal of Nutrition (2003), 89, 295–301 q The Authors 2003 DOI: 10.1079/BJN2002776 Plasma homocysteine concentration is decreased by dietary intervention*" }, { "docid": "21636085", "text": "BACKGROUND Increased plasma homocysteine is associated with coronary artery disease, peripheral vascular disease and venous thrombosis. Folic acid is the most effective therapy for reducing homocysteine levels. The lowest effective supplement of folic acid is not known, particularly for the elderly who have the highest prevalence of these conditions. AIM To explore the effects of daily supplements of 0, 50, 100, 200, 400 and 600 microg folic acid on plasma homocysteine in an elderly population. \n DESIGN Randomized double-blind placebo-controlled trial. \n METHODS Participants (n=368) aged 65-75 years were randomly allocated to receive one of the treatments for 6 weeks. Plasma homocysteine was recorded after 3 weeks and 6 weeks of supplementation. \n RESULTS Only the 400 microg and 600 microg groups had significantly lower homocysteine levels compared to placebo (p=0.038 and p<0.001, respectively). Using multiple linear regression and each individual's total folic acid intake (diet plus supplement), a total daily folic acid intake of 926 microg per day would be required to ensure that 95% of the elderly population would be without cardiovascular risk from folate deficiency. DISCUSSION A daily folic acid intake of 926 microg is unlikely to be achieved by diet alone. Individual supplementation or fortification of food with folic acid will be required to reach this target.", "title": "The effect of folic acid supplementation on plasma homocysteine in an elderly population." }, { "docid": "18174210", "text": "BACKGROUND The heritable haemoglobinopathy alpha(+)-thalassaemia is caused by the reduced synthesis of alpha-globin chains that form part of normal adult haemoglobin (Hb). Individuals homozygous for alpha(+)-thalassaemia have microcytosis and an increased erythrocyte count. Alpha(+)-thalassaemia homozygosity confers considerable protection against severe malaria, including severe malarial anaemia (SMA) (Hb concentration < 50 g/l), but does not influence parasite count. We tested the hypothesis that the erythrocyte indices associated with alpha(+)-thalassaemia homozygosity provide a haematological benefit during acute malaria. \n METHODS AND FINDINGS Data from children living on the north coast of Papua New Guinea who had participated in a case-control study of the protection afforded by alpha(+)-thalassaemia against severe malaria were reanalysed to assess the genotype-specific reduction in erythrocyte count and Hb levels associated with acute malarial disease. We observed a reduction in median erythrocyte count of approximately 1.5 x 10(12)/l in all children with acute falciparum malaria relative to values in community children (p < 0.001). We developed a simple mathematical model of the linear relationship between Hb concentration and erythrocyte count. This model predicted that children homozygous for alpha(+)-thalassaemia lose less Hb than children of normal genotype for a reduction in erythrocyte count of >1.1 x 10(12)/l as a result of the reduced mean cell Hb in homozygous alpha(+)-thalassaemia. In addition, children homozygous for alpha(+)-thalassaemia require a 10% greater reduction in erythrocyte count than children of normal genotype (p = 0.02) for Hb concentration to fall to 50 g/l, the cutoff for SMA. We estimated that the haematological profile in children homozygous for alpha(+)-thalassaemia reduces the risk of SMA during acute malaria compared to children of normal genotype (relative risk 0.52; 95% confidence interval [CI] 0.24-1.12, p = 0.09). \n CONCLUSIONS The increased erythrocyte count and microcytosis in children homozygous for alpha(+)-thalassaemia may contribute substantially to their protection against SMA. A lower concentration of Hb per erythrocyte and a larger population of erythrocytes may be a biologically advantageous strategy against the significant reduction in erythrocyte count that occurs during acute infection with the malaria parasite Plasmodium falciparum. This haematological profile may reduce the risk of anaemia by other Plasmodium species, as well as other causes of anaemia. Other host polymorphisms that induce an increased erythrocyte count and microcytosis may confer a similar advantage.", "title": "Increased Microerythrocyte Count in Homozygous α+-Thalassaemia Contributes to Protection against Severe Malarial Anaemia" }, { "docid": "27408104", "text": "Diet-related adaptive gene (DRAG) polymorphisms identified in specific populations are associated with chronic disorders in carriers of the adaptive alleles due to changes in dietary and lifestyle patterns in recent times. Mexico's population is comprised of Amerindians (AM) and Mestizos who have variable AM, European (EUR) and African genetic ancestry and an increased risk of nutrition-related chronic diseases. Nutritional advice based on the Mexican genome and the traditional food culture is needed to develop preventive and therapeutic strategies. Therefore, we aimed to provide a prevalence profile of several DRAG polymorphisms in the Mexican population, including Central West (CW) Mexico subpopulations. Geographic heat maps were built using ArcGIS10 (Esri, Redlands, CA, USA) software, based on the published data of the MTHFR C677T (rs1801133), ABCA1 Arg230Cys (rs9282541), APOE T388C (rs429358)/C526T (rs7412), LCT C-13910T (rs4988235) polymorphisms and AMY1 copy number variation (CNV). Also, new data obtained by allelic discrimination-real-time polymerase chain reaction (RT-PCR) assays for the MTHFR, ABCA1, and APOE polymorphisms as well as the AMY1 CNV in the CW Mexico subpopulations with different proportions of AM and EUR ancestry were included. In the CW region, the highest frequency of the MTHFR 677T, ABCA1 230C and APOE ε4 adaptive alleles was observed in the AM groups, followed by Mestizos with intermediate AM ancestry. The LCT-13910T allele frequency was highest in Mestizos-EUR but extremely low in AM, while the AMY1 diploid copy number was 6.82 ± 3.3 copies. Overall, the heat maps showed a heterogeneous distribution of the DRAG polymorphisms, in which the AM groups revealed the highest frequencies of the adaptive alleles followed by Mestizos. Given these genetic differences, genome-based nutritional advice should be tailored in a regionalized and individualized manner according to the available foods and Mexican traditional food culture that may lead to a healthier dietary pattern.", "title": "Tailoring Nutritional Advice for Mexicans Based on Prevalence Profiles of Diet-Related Adaptive Gene Polymorphisms" }, { "docid": "10557471", "text": "The aim of the present investigation was to study the effect of a dietary intervention which combined nutrition information with increased availability of vegetables, fruits and wholegrain bread. The effect of the intervention was determined by changes in the intake of vegetables, fruits, wholegrain bread and estimated nutrients. Furthermore, the study investigated whether changes in relative contribution from different food sources of folate were related to changes in the concentration of plasma total homocysteine (p-tHcy). The 5-month intervention study included 376 male recruits from the Norwegian National Guard, Vaernes (intervention group) and 105 male recruits from the Norwegian National Guard, Heggelia (control group). The study resulted in an increase in the total consumption of vegetables, fruits, berries and juice (P < 0.001) and of wholegrain bread (P < 0.001). The participants in the intervention group showed a higher increase in the intake of dietary fibre (P < 0.001) and folate (P < 0.001) compared with the control group. The relative contribution of folate intake from fruits, vegetables and wholegrain bread was higher in the intervention group compared with the control group (P < 0.001 for all). The increased intake of folate from wholegrain bread was inversely associated with a reduced concentration of p-tHcy (P = 0.017). In summary, the dietary intervention resulted in an increased intake of vegetables, fruits and wholegrain bread and a subsequent increase in folate intake from these food components. Reduction in the concentration of p-tHcy was significantly related to an increased folate intake due to an increased consumption of wholegrain bread.", "title": "Association between folate intake from different food sources in Norway and homocysteine status in a dietary intervention among young male adults." }, { "docid": "32328114", "text": "Stroke ranks as the third leading cause of death in the United States. It is now estimated that there are more than 700 000 incident strokes annually and 4.4 million stroke survivors.1 2 The economic burden of stroke was estimated by the American Heart Association to be $51 billion (direct and indirect costs) in 1999.3 Despite the advent of treatment of selected patients with acute ischemic stroke with tissue plasminogen activator and the promise of other experimental therapies, the best approach to reducing the burden of stroke remains prevention.4 5 High-risk or stroke-prone individuals can be identified and targeted for specific interventions.6 This is important because epidemiological data suggest a substantial leveling off of prior declines in stroke-related mortality and a possible increase in stroke incidence.7 8 The Stroke Council of the American Heart Association formed an ad hoc writing group to provide a clear and concise overview of the evidence regarding various established and potential stroke risk factors. The writing group was chosen based on expertise in specific subject areas, and it used literature review, reference to previously published guidelines, and expert opinion to summarize existing evidence and formulate recommendations (Table 1⇓). View this table: Table 1. Levels of Evidence and Grading of Recommendations As given in Tables 2 through 4⇓⇓⇓, risk factors or risk markers for a first stroke were classified according to potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented, less well documented).5 The tables give the estimated prevalence, population attributable risk, relative risk, and risk reduction with treatment for each factor when known. Population attributable risk reflects the proportion of ischemic strokes in the population that can be attributed to a particular risk factor and is given by the formula 100×[prevalence(relative risk−1)/prevalence(relative risk−1)+1]). …", "title": "Primary prevention of ischemic stroke: A statement for healthcare professionals from the Stroke Council of the American Heart Association." }, { "docid": "36558211", "text": "OBJECTIVES To explore the different characteristics of high and low fat consumers, in particular their macronutrient intake and body mass index. \n DESIGN Reanalysis of data from the Dietary and Nutritional Survey of British Adults. Comparisons were made between groups defined as high and low fat consumers on the basis of 7-day weighed food records considered to be valid for energy intake. Individuals were classified in two ways according to the percentage energy from fat (FAT%) and the absolute amount of fat consumed (FATg). The criteria for classification of the high FAT% being > 45% (high fat) and < or = 35% (low fat). For the FATg group the threshold for the high fat group was > 138 g/day (men) and > 102 g/day (women), and for the low fat group < 85 g/day (men) and < 70 g/day (women). \n SETTING Dietary data was collected from private households in Great Britain between 1986 and 1987. SUBJECTS From the total population of 2197, individuals who were slimming, ill or had an EI: BMR of < 1.2 were excluded in order to use data which was most likely to represent habitual energy intakes. From the remaining 1240 subjects, 10.8% of this sample (6.1% of the total population) were classified as low fat consumers (76 men and 58 women) and 15.4% high fat (8.7% of the total population, 93 men and 98 women). \n MAIN OUTCOME MEASURES Macronutrient consumption and body mass index (BMI). \n RESULTS 30% of the subjects changed fat group classification when the criteria of defining high and low fat groups altered from FAT% to FATg. Nutrient intakes differed according to definition of the groups. The high fat FATg group ate significantly more of all nutrients than the low fat FATg group. However, this was not seen for the FAT% analysis, with the high fat group eating more fat and less carbohydrate. The average BMI tended to be higher in the high fat than the low fat groups, particularly in the FATg analysis. However, the high fat group contained a wide range of BMIs. Further exploration of BMI in the high fat groups, showed that age (an 11-year difference) was the only variable to distinguish individuals in the top and bottom quartiles of BMI. \n CONCLUSIONS High and low fat consumers differ according to a number of variables, and this is affected by how these groups are defined (FAT% or FATg). High fat consumers tend to have a higher BMI than low fat consumers, but not all high fat consumers are overweight or obese.", "title": "High and low fat consumers, their macronutrient intake and body mass index: further analysis of the National Diet and Nutrition Survey of British Adults." }, { "docid": "1456068", "text": "BACKGROUND Although cigarette smoking, excessive alcohol drinking, obesity, and several other well-studied unhealthy lifestyle-related factors each have been linked to the risk of multiple chronic diseases and premature death, little is known about the combined impact on mortality outcomes, in particular among Chinese and other non-Western populations. The objective of this study was to quantify the overall impact of lifestyle-related factors beyond that of active cigarette smoking and alcohol consumption on all-cause and cause-specific mortality in Chinese women. \n METHODS AND FINDINGS We used data from the Shanghai Women's Health Study, an ongoing population-based prospective cohort study in China. Participants included 71,243 women aged 40 to 70 years enrolled during 1996-2000 who never smoked or drank alcohol regularly. A healthy lifestyle score was created on the basis of five lifestyle-related factors shown to be independently associated with mortality outcomes (normal weight, lower waist-hip ratio, daily exercise, never exposed to spouse's smoking, higher daily fruit and vegetable intake). The score ranged from zero (least healthy) to five (most healthy) points. During an average follow-up of 9 years, 2,860 deaths occurred, including 775 from cardiovascular disease (CVD) and 1,351 from cancer. Adjusted hazard ratios for mortality decreased progressively with an increasing number of healthy lifestyle factors. Compared to women with a score of zero, hazard ratios (95% confidence intervals) for women with four to five factors were 0.57 (0.44-0.74) for total mortality, 0.29 (0.16-0.54) for CVD mortality, and 0.76 (0.54-1.06) for cancer mortality. The inverse association between the healthy lifestyle score and mortality was seen consistently regardless of chronic disease status at baseline. The population attributable risks for not having 4-5 healthy lifestyle factors were 33% for total deaths, 59% for CVD deaths, and 19% for cancer deaths. \n CONCLUSIONS In this first study, to our knowledge, to quantify the combined impact of lifestyle-related factors on mortality outcomes in Chinese women, a healthier lifestyle pattern-including being of normal weight, lower central adiposity, participation in physical activity, nonexposure to spousal smoking, and higher fruit and vegetable intake-was associated with reductions in total and cause-specific mortality among lifetime nonsmoking and nondrinking women, supporting the importance of overall lifestyle modification in disease prevention. Please see later in the article for the Editors' Summary.", "title": "Combined Impact of Lifestyle-Related Factors on Total and Cause-Specific Mortality among Chinese Women: Prospective Cohort Study" }, { "docid": "19278208", "text": "Background/Objectives:Folic acid supplementation has been suggested to reduce the risk of preeclampsia. However, results from few epidemiologic studies have been inconclusive. We investigated the hypothesis that folic acid supplementation and dietary folate intake before conception and during pregnancy reduce the risk of preeclampsia. Subjects/Methods:A birth cohort study was conducted in 2010–2012 at the Gansu Provincial Maternity & Child Care Hospital in Lanzhou, China. A total of 10 041 pregnant women without chronic hypertension or gestational hypertension were enrolled. Results:Compared with nonusers, folic acid supplement users had a reduced risk of preeclampsia (OR=0.61, 95% CI: 0.43–0.87). A significant dose–response of duration of use was observed among women who used folic acid supplemention during pregnancy only (P-trend=0.007). The reduced risk associated with folic acid supplement was similar for mild or severe preeclampsia and for early- or late-onset preeclampsia, although the statistical significant associations were only observed for mild (OR=0.50, 95% CI: 0.30–0.81) and late-onset (OR=0.60, 95% CI: 0.42–0.86) preeclampsia. The reduced risk associated with dietary folate intake during pregnancy was only seen for severe preeclampsia (OR=0.52, 95% CI: 0.31–0.87, for the highest quartile of dietary folate intake compared with the lowest).Conclusions:Our study results suggest that folic acid supplementation and higher dietary folate intake during pregnancy reduce the risk of preeclampsia. Future studies are needed to confirm the associations.", "title": "Folic acid supplementation and dietary folate intake, and risk of preeclampsia" }, { "docid": "2138767", "text": "AIMS Cardiovascular disease (CVD) is now the most prevalent and debilitating disease affecting the Chinese population. The goal of the present manuscript was to analyse cardiovascular risk factors and the prevalence of non-fatal CVDs from data gathered from the 2007-2008 China National Diabetes and Metabolic Disorders Study. \n METHODS AND RESULTS A nationally representative sample of 46 239 adults, 20 years of age or older, was randomly recruited using a multistage stratified design method. Lifestyle factors, diagnosis of CVD, stroke, diabetes, and family history of each subject were collected, and an oral glucose tolerance test or a standard meal test was performed. Various non-fatal CVDs were reported by the subjects. SUDAAN software was used to perform all weighted statistical analyses, with P < 0.05 considered statistically significant. The prevalence of coronary heart disease, stroke, and CVDs was 0.74, 1.07, and 1.78% in males; and 0.51, 0.60, and 1.10% in females, respectively. The presence of CVDs increased with age in both males and females. The prevalence of being overweight or obese, hypertension, dyslipidaemia, or hyperglycaemia was 36.67, 30.09, 67.43, and 26.69% in males; and 29.77, 24.79, 63.98, and 23.62% in females, respectively. In the total sample of 46 239 patients, the prevalence of one subject having 1, 2, 3, or ≥4 of the 5 defined risk factors (i.e. smoking, overweight or obese, hypertension, dyslipidaemia, or hyperglycaemia) was 31.17, 27.38, 17.76, and 10.19%, respectively. Following adjustment for gender and age, the odds ratio of CVDs for those who had 1, 2, 3, or ≥4 risk factors was 2.36, 4.24, 4.88, and 7.22, respectively, when compared with patients with no risk factors. \n CONCLUSION Morbidity attributed to the five defined cardiovascular risk factors was high in the Chinese population, with multiple risk factors present in the same individual. Therefore, reasonable prevention strategies should be designed to attenuate the rapid rise in cardiovascular morbidity.", "title": "Prevalence of cardiovascular disease risk factor in the Chinese population: the 2007-2008 China National Diabetes and Metabolic Disorders Study." }, { "docid": "16256507", "text": "CONTEXT Adequate vitamin D status for optimum bone health has received increased recognition in recent years; however, the ideal intake is not known. Serum 25-hydroxyvitamin D is the generally accepted indicator of vitamin D status, but no universal reference level has been reached. \n OBJECTIVE To investigate the relative importance of high calcium intake and serum 25-hydroxyvitamin D for calcium homeostasis, as determined by serum intact parathyroid hormone (PTH). \n DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study of 2310 healthy Icelandic adults who were divided equally into 3 age groups (30-45 years, 50-65 years, or 70-85 years) and recruited from February 2001 to January 2003. They were administered a semi-quantitative food frequency questionnaire, which assessed vitamin D and calcium intake. Participants were further divided into groups according to calcium intake (<800 mg/d, 800-1200 mg/d, and >1200 mg/d) and serum 25-hydroxyvitamin D level (<10 ng/mL, 10-18 ng/mL, and >18 ng/mL). \n MAIN OUTCOME MEASURE Serum intact PTH as determined by calcium intake and vitamin D. RESULTS A total of 944 healthy participants completed all parts of the study. After adjusting for relevant factors, serum PTH was lowest in the group with a serum 25-hydroxyvitamin D level of more than 18 ng/mL but highest in the group with a serum 25-hydroxyvitamin D level of less than 10 ng/mL. At the low serum 25-hydroxyvitamin D level (<10 ng/mL), calcium intake of less than 800 mg/d vs more than 1200 mg/d was significantly associated with higher serum PTH (P = .04); and at a calcium intake of more than 1200 mg/d, there was a significant difference between the lowest and highest vitamin D groups (P = .04). \n CONCLUSIONS As long as vitamin D status is ensured, calcium intake levels of more than 800 mg/d may be unnecessary for maintaining calcium metabolism. Vitamin D supplements are necessary for adequate vitamin D status in northern climates.", "title": "Relationship between serum parathyroid hormone levels, vitamin D sufficiency, and calcium intake." }, { "docid": "21571708", "text": "CONTEXT Circulating concentration of lipoprotein(a) (Lp[a]), a large glycoprotein attached to a low-density lipoprotein-like particle, may be associated with risk of coronary heart disease (CHD) and stroke. \n OBJECTIVE To assess the relationship of Lp(a) concentration with risk of major vascular and nonvascular outcomes. STUDY SELECTION Long-term prospective studies that recorded Lp(a) concentration and subsequent major vascular morbidity and/or cause-specific mortality published between January 1970 and March 2009 were identified through electronic searches of MEDLINE and other databases, manual searches of reference lists, and discussion with collaborators. \n DATA EXTRACTION Individual records were provided for each of 126,634 participants in 36 prospective studies. During 1.3 million person-years of follow-up, 22,076 first-ever fatal or nonfatal vascular disease outcomes or nonvascular deaths were recorded, including 9336 CHD outcomes, 1903 ischemic strokes, 338 hemorrhagic strokes, 751 unclassified strokes, 1091 other vascular deaths, 8114 nonvascular deaths, and 242 deaths of unknown cause. Within-study regression analyses were adjusted for within-person variation and combined using meta-analysis. Analyses excluded participants with known preexisting CHD or stroke at baseline. \n DATA SYNTHESIS Lipoprotein(a) concentration was weakly correlated with several conventional vascular risk factors and it was highly consistent within individuals over several years. Associations of Lp(a) with CHD risk were broadly continuous in shape. In the 24 cohort studies, the rates of CHD in the top and bottom thirds of baseline Lp(a) distributions, respectively, were 5.6 (95% confidence interval [CI], 5.4-5.9) per 1000 person-years and 4.4 (95% CI, 4.2-4.6) per 1000 person-years. The risk ratio for CHD, adjusted for age and sex only, was 1.16 (95% CI, 1.11-1.22) per 3.5-fold higher usual Lp(a) concentration (ie, per 1 SD), and it was 1.13 (95% CI, 1.09-1.18) following further adjustment for lipids and other conventional risk factors. The corresponding adjusted risk ratios were 1.10 (95% CI, 1.02-1.18) for ischemic stroke, 1.01 (95% CI, 0.98-1.05) for the aggregate of nonvascular mortality, 1.00 (95% CI, 0.97-1.04) for cancer deaths, and 1.00 (95% CI, 0.95-1.06) for nonvascular deaths other than cancer. \n CONCLUSION Under a wide range of circumstances, there are continuous, independent, and modest associations of Lp(a) concentration with risk of CHD and stroke that appear exclusive to vascular outcomes.", "title": "Lipoprotein(a) concentration and the risk of coronary heart disease, stroke, and nonvascular mortality." }, { "docid": "6327940", "text": "Amino acids modulate the secretion of both insulin and glucagon; the composition of dietary protein therefore has the potential to influence the balance of glucagon and insulin activity. Soy protein, as well as many other vegan proteins, are higher in non-essential amino acids than most animal-derived food proteins, and as a result should preferentially favor glucagon production. Acting on hepatocytes, glucagon promotes (and insulin inhibits) cAMP-dependent mechanisms that down-regulate lipogenic enzymes and cholesterol synthesis, while up-regulating hepatic LDL receptors and production of the IGF-I antagonist IGFBP-1. The insulin-sensitizing properties of many vegan diets--high in fiber, low in saturated fat--should amplify these effects by down-regulating insulin secretion. Additionally, the relatively low essential amino acid content of some vegan diets may decrease hepatic IGF-I synthesis. Thus, diets featuring vegan proteins can be expected to lower elevated serum lipid levels, promote weight loss, and decrease circulating IGF-I activity. The latter effect should impede cancer induction (as is seen in animal studies with soy protein), lessen neutrophil-mediated inflammatory damage, and slow growth and maturation in children. In fact, vegans tend to have low serum lipids, lean physiques, shorter stature, later puberty, and decreased risk for certain prominent 'Western' cancers; a vegan diet has documented clinical efficacy in rheumatoid arthritis. Low-fat vegan diets may be especially protective in regard to cancers linked to insulin resistance--namely, breast and colon cancer--as well as prostate cancer; conversely, the high IGF-I activity associated with heavy ingestion of animal products may be largely responsible for the epidemic of 'Western' cancers in wealthy societies. Increased phytochemical intake is also likely to contribute to the reduction of cancer risk in vegans. Regression of coronary stenoses has been documented during low-fat vegan diets coupled with exercise training; such regimens also tend to markedly improve diabetic control and lower elevated blood pressure. Risk of many other degenerative disorders may be decreased in vegans, although reduced growth factor activity may be responsible for an increased risk of hemorrhagic stroke. By altering the glucagon/insulin balance, it is conceivable that supplemental intakes of key non-essential amino acids could enable omnivores to enjoy some of the health advantages of a vegan diet. An unnecessarily high intake of essential amino acids--either in the absolute sense or relative to total dietary protein--may prove to be as grave a risk factor for 'Western' degenerative diseases as is excessive fat intake.", "title": "Vegan proteins may reduce risk of cancer, obesity, and cardiovascular disease by promoting increased glucagon activity." }, { "docid": "10692948", "text": "CONTEXT Early childhood introduction of nutritional habits aimed at atherosclerosis prevention is compatible with normal growth, but its effect on neurological development is unknown. \n OBJECTIVE To analyze how parental counseling aimed at keeping children's diets low in saturated fat and cholesterol influences neurodevelopment during the first 5 years of life. \n DESIGN Randomized controlled trial conducted between February 1990 and November 1996. \n SETTING Outpatient clinic of a university department in Turku, Finland. \n PARTICIPANTS A total of 1062 seven-month-old infants and their parents, recruited at well-baby clinics between 1990 and 1992. At age 5 years, 496 children still living in the city of Turku were available to participate in neurodevelopmental testing. \n INTERVENTION Participants were randomly assigned to receive individualized counseling aimed at limiting the child's fat intake to 30% to 35% of daily energy, with a saturated:monounsaturated:polyunsaturated fatty acid ratio of 1:1:1 and a cholesterol intake of less than 200 mg/d (n = 540) or usual health education (control group, n = 522). \n MAIN OUTCOME MEASURES Nutrient intake, serum lipid concentrations, and neurological development at 5 years, among children in the intervention vs control groups. \n RESULTS Absolute and relative intakes of fat, saturated fatty acids, and cholesterol among children in the intervention group were markedly less than the respective values of control children. Mean (SD) percentages of daily energy at age 5 years for the intervention vs control groups were as follows: for total fat, 30.6% (4.5%) vs 33.4% (4.4%) (P<. 001); and for saturated fat, 11.7% (2.3%) vs 14.5% (2.4%) (P<.001). Mean intakes of cholesterol were 164.2 mg (60.1 mg) and 192.5 mg (71. 9 mg) (P<.001) for the intervention and control groups, respectively. Serum cholesterol concentrations were continuously 3% to 5% lower in children in the intervention group than in children in the control group. At age 5 years, mean (SD) serum cholesterol concentration of the intervention group was 4.27 (0.63) mmol/L (165 [24] mg/dL) and of the control group, 4.41 (0.74) mmol/L (170 [29] mg/dL) (P =.04). Neurological development of children in the intervention group was at least as good as that of children in the control group. Relative risks for children in the intervention group to fail tests of speech and language skills, gross motor functioning plus perception, and visual motor skills were 0.95 (90% confidence interval [CI], 0.60-1.49), 0.95 (90% CI, 0.58-1.55), and 0.65 (90% CI, 0.39-1.08), respectively (P =.85,.86, and.16, respectively, vs control children). \n CONCLUSION Our data indicate that repeated child-targeted dietary counseling of parents during the first 5 years of a child's life lessens age-associated increases in children's serum cholesterol and is compatible with normal neurological development. JAMA. 2000;284:993-1000", "title": "Neurological development of 5-year-old children receiving a low-saturated fat, low-cholesterol diet since infancy: A randomized controlled trial." }, { "docid": "12770738", "text": "BACKGROUND Questions remain as to whether higher levels of cardiorespiratory fitness, a measure of regular physical activity, are associated with lower risk of cardiovascular disease (CVD) mortality in overweight and obese individuals with diabetes. Our objective was to quantify the independent and joint relations of cardiorespiratory fitness (hereafter, fitness) and body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters) with CVD mortality in men with diabetes. \n METHODS This study was conducted using prospective observational data from the Aerobics Center Longitudinal Study. Study participants comprised 2316 men with no history of stroke or myocardial infarction and who were diagnosed as having diabetes (mean [SD] age, 50 [10] years); had a medical examination, including a maximal exercise test during 1970 to 1997 with mortality surveillance to December 31, 1998; and had a BMI of 18.5 or greater and less than 35.0. The main outcome measure was CVD mortality across levels of fitness with stratification by BMI. \n RESULTS We identified 179 CVD deaths during a mean (SD) follow-up of 15.9 (7.9) years and 36,710 man-years of exposure. In a model containing age, examination year, fasting glucose level, systolic blood pressure, parental history of premature CVD, total cholesterol level, cigarette smoking, abnormal resting, and exercise electrocardiograms, a significantly higher adjusted risk of mortality was observed in men with a low fitness level who were normal weight (hazard ratio, 2.7 [95% confidence interval, 1.3-5.7]), overweight (hazard ratio, 2.7 [95% confidence interval, 1.4-5.1]), and class 1 obese (hazard ratio, 2.8 [95% confidence interval, 1.4-5.1]) compared with normal weight men with a high fitness level. \n CONCLUSION In this cohort of men with diabetes, low fitness level was associated with increased risk of CVD mortality within normal weight, overweight, and class 1 obese weight categories.", "title": "Cardiorespiratory fitness and body mass index as predictors of cardiovascular disease mortality among men with diabetes." } ]

[ { "docid": "37424881", "text": "OBJECTIVE Folate and vitamin B12 are two vital regulators in the metabolic process of homocysteine, which is a risk factor of atherothrombotic events. Low folate intake or low plasma folate concentration is associated with increased stroke risk. Previous randomized controlled trials presented discordant findings in the effect of folic acid supplementation-based homocysteine lowering on stroke risk. The aim of the present review was to perform a meta-analysis of relevant randomized controlled trials to check the how different folate fortification status might affect the effects of folic acid supplementation in lowering homocysteine and reducing stroke risk. \n DESIGN Relevant randomized controlled trials were identified through formal literature search. Homocysteine reduction was compared in subgroups stratified by folate fortification status. Relative risks with 95 % confidence intervals were used as a measure to assess the association between folic acid supplementation and stroke risk. \n SETTING The meta-analysis included fourteen randomized controlled trials, SUBJECTS A total of 39 420 patients. \n RESULTS Homocysteine reductions were 26·99 (sd 1·91) %, 18·38 (sd 3·82) % and 21·30 (sd 1·98) %, respectively, in the subgroups without folate fortification, with folate fortification and with partial folate fortification. Significant difference was observed between the subgroups with folate fortification and without folate fortification (P=0·05). The relative risk of stroke was 0·88 (95 % CI 0·77, 1·00, P=0·05) in the subgroup without folate fortification, 0·94 (95 % CI 0·58, 1·54, P=0·82) in the subgroup with folate fortification and 0·91 (95 % CI 0·82, 1·01, P=0·09) in the subgroup with partial folate fortification. \n CONCLUSIONS Folic acid supplementation might have a modest benefit on stroke prevention in regions without folate fortification.", "title": "The effect of folate fortification on folic acid-based homocysteine-lowering intervention and stroke risk: a meta-analysis." } ]

[ { "docid": "42441846", "text": "INTRODUCTION Elevated plasma total homocysteine is a major risk for coronary artery disease (CAD). Methyltetrahydrofolate reductase (MTHFR) is a main regulatory enzyme in homocysteine metabolism; a common C677T mutation in the MTHFR gene results in decreased enzyme activity, and contributes to increased homocysteine levels and decreased folate levels. We investigated the frequency of MTHFR C677T alleles in a Korean population, determined the genotype-specific threshold levels of folate or vitamin B12, and investigated the relationship between the TT genotype and the risk of CAD. MATERIALS AND METHODS We enrolled a study population of 163 CAD patients and 50 control subjects, and screened the MTHFR C677T polymorphism using real-time PCR with melting point analysis. Levels of plasma homocysteine, folate and vitamin B12 were also determined. We then defined the genotype-specific threshold values of folate and vitamin B12 required to keep homocysteine levels in a normal range for individuals of each MTHFR C677T genotype. \n RESULTS The frequency of the TT genotype was 18% in control subjects and 26% in patients group (P>0.05). Individuals homozygous for the TT genotype had significantly elevated homocysteine levels (P<0.05). The genotype-specific folate threshold level was significantly higher in TT individuals than in the CC or CT genotypes. The OR of individuals with low folate status and the TT genotype to estimate the relative risk of CAD was 2.2 and the OR of those with high folate status and the TT genotype was 1.5 (95% CI, 0.5-9.6 and 0.7-3.2, respectively). \n CONCLUSION We were able to define a gene-nutrient interaction that shows a higher risk for CAD based on specific threshold folate levels required by different MTHFR C677T genotypes in a Korean population.", "title": "Gene--nutrition interactions in coronary artery disease: correlation between the MTHFR C677T polymorphism and folate and homocysteine status in a Korean population." }, { "docid": "8595678", "text": "BACKGROUND The MTHFR 677C→T polymorphism has been associated with raised homocysteine concentration and increased risk of stroke. A previous overview showed that the effects were greatest in regions with low dietary folate consumption, but differentiation between the effect of folate and small-study bias was difficult. A meta-analysis of randomised trials of homocysteine-lowering interventions showed no reduction in coronary heart disease events or stroke, but the trials were generally set in populations with high folate consumption. We aimed to reduce the effect of small-study bias and investigate whether folate status modifies the association between MTHFR 677C→T and stroke in a genetic analysis and meta-analysis of randomised controlled trials. \n METHODS We established a collaboration of genetic studies consisting of 237 datasets including 59,995 individuals with data for homocysteine and 20,885 stroke events. We compared the genetic findings with a meta-analysis of 13 randomised trials of homocysteine-lowering treatments and stroke risk (45,549 individuals, 2314 stroke events, 269 transient ischaemic attacks). \n FINDINGS The effect of the MTHFR 677C→T variant on homocysteine concentration was larger in low folate regions (Asia; difference between individuals with TT versus CC genotype, 3·12 μmol/L, 95% CI 2·23 to 4·01) than in areas with folate fortification (America, Australia, and New Zealand, high; 0·13 μmol/L, -0·85 to 1·11). The odds ratio (OR) for stroke was also higher in Asia (1·68, 95% CI 1·44 to 1·97) than in America, Australia, and New Zealand, high (1·03, 0·84 to 1·25). Most randomised trials took place in regions with high or increasing population folate concentrations. The summary relative risk (RR) of stroke in trials of homocysteine-lowering interventions (0·94, 95% CI 0·85 to 1·04) was similar to that predicted for the same extent of homocysteine reduction in large genetic studies in populations with similar folate status (predicted RR 1·00, 95% CI 0·90 to 1·11). Although the predicted effect of homocysteine reduction from large genetic studies in low folate regions (Asia) was larger (RR 0·78, 95% CI 0·68 to 0·90), no trial has evaluated the effect of lowering of homocysteine on stroke risk exclusively in a low folate region. \n INTERPRETATION In regions with increasing levels or established policies of population folate supplementation, evidence from genetic studies and randomised trials is concordant in suggesting an absence of benefit from lowering of homocysteine for prevention of stroke. Further large-scale genetic studies of the association between MTHFR 677C→T and stroke in low folate settings are needed to distinguish effect modification by folate from small-study bias. If future randomised trials of homocysteine-lowering interventions for stroke prevention are undertaken, they should take place in regions with low folate consumption. \n FUNDING Full funding sources listed at end of paper (see Acknowledgments).", "title": "Effect modification by population dietary folate on the association between MTHFR genotype, homocysteine, and stroke risk: a meta-analysis of genetic studies and randomised trials" }, { "docid": "12810152", "text": "CONTEXT Hyperhomocysteinemia is caused by genetic and lifestyle influences, including low intakes of folate and vitamin B6. However, prospective data relating intake of these vitamins to risk of coronary heart disease (CHD) are not available. \n OBJECTIVE To examine intakes of folate and vitamin B6 in relation to the incidence of nonfatal myocardial infarction (MI) and fatal CHD. \n DESIGN Prospective cohort study. \n SETTING AND PATIENTS In 1980, a total of 80082 women from the Nurses' Health Study with no previous history of cardiovascular disease, cancer, hypercholesterolemia, or diabetes completed a detailed food frequency questionnaire from which we derived usual intake of folate and vitamin B6. \n MAIN OUTCOME MEASURE Nonfatal MI and fatal CHD confirmed by World Health Organization criteria. \n RESULTS During 14 years of follow-up, we documented 658 incident cases of nonfatal MI and 281 cases of fatal CHD. After controlling for cardiovascular risk factors, including smoking and hypertension and intake of alcohol, fiber, vitamin E, and saturated, polyunsaturated, and trans fat, the relative risks (RRs) of CHD between extreme quintiles were 0.69 (95% confidence interval [CI], 0.55-0.87) for folate (median intake, 696 microg/d vs 158 microg/d) and 0.67 (95% CI, 0.53-0.85) for vitamin B6 (median intake, 4.6 mg/d vs 1.1 mg/d). Controlling for the same variables, the RR was 0.55 (95% CI, 0.41-0.74) among women in the highest quintile of both folate and vitamin B6 intake compared with the opposite extreme. Risk of CHD was reduced among women who regularly used multiple vitamins (RR=0.76; 95% CI, 0.65-0.90), the major source of folate and vitamin B6, and after excluding multiple vitamin users, among those with higher dietary intakes of folate and vitamin B6. In a subgroup analysis, compared with nondrinkers, the inverse association between a high-folate diet and CHD was strongest among women who consumed up to 1 alcoholic beverage per day (RR =0.69; 95% CI, 0.49-0.97) or more than 1 drink per day (RR=0.27; 95% CI, 0.13-0.58). \n CONCLUSION These results suggest that intake of folate and vitamin B6 above the current recommended dietary allowance may be important in the primary prevention of CHD among women.", "title": "Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women." }, { "docid": "2647374", "text": "INTRODUCTION Deregulated or excessive host immune responses contribute to the pathogenesis of sepsis. Toll-like receptor (TLR) signaling pathways and their negative regulators play a pivotal role in the modulation of host immune responses and the development of sepsis. The objective of this study was to investigate the association of variants in the TLR signaling pathway genes and their negative regulator genes with susceptibility to sepsis in the Chinese Han population. \n METHODS Patients with severe sepsis (n = 378) and healthy control subjects (n = 390) were enrolled. Five genes, namely TLR2, TLR4, TLR9, MyD88 and TOLLIP, were investigated for their association with sepsis susceptibility by a tag single nucleotide polymorphism (SNP) strategy. Twelve tag SNPs were selected based on the data of Chinese Han in Beijing from the HapMap project and genotyped by direct sequencing. The mRNA expression levels of TOLLIP were determined using real-time quantitative Polymerase Chain Reaction (PCR) assays, and concentrations of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay (ELISA). \n RESULTS Our results showed that the minor C-allele of rs5743867 in TOLLIP was significantly associated with the decreased risk of sepsis (Padj = 0.00062, odds ratio (OR)adj = 0.71, 95% confidence interval (CI) 0.59 to 0.86) after adjustment for covariates in multiple logistic regression analysis. A 3-SNP haplotype block harboring the associated SNP rs5743867 also displayed strong association with omnibus test P value of 0.00049. Haplotype GTC showed a protective role against sepsis (Padj = 0.0012), while haplotype GCT showed an increased risk for sepsis (Padj = 0.00092). After exposure to lipopolysaccharide (LPS), TOLLIP mRNA expression levels in peripheral blood mononuclear cells (PBMCs) from homozygotes for the rs5743867C allele were significantly higher than in heterozygotes and homozygotes for the rs5743867T allele (P = 0.013 and P = 0.01, respectively). Moreover, the concentrations of TNF-α and IL-6 in culture supernatants were significantly lower in the subjects of rs5743867CC genotype than in CT and TT genotype subjects (P = 0.016 and P = 0.003 for TNF-α; P = 0.01 and P = 0.002 for IL-6, respectively). \n CONCLUSIONS Our findings indicated that the variants in TOLLIP were significantly associated with sepsis susceptibility in the Chinese Han population.", "title": "Variants in the Toll-interacting protein gene are associated with susceptibility to sepsis in the Chinese Han population" }, { "docid": "18557974", "text": "High plasma total homocysteine (tHcy) concentration is reported to be a risk factor for vascular diseases. We investigated the extent to which serum folate and plasma tHcy respond to a high intake of natural folate from food. Thirty-seven healthy females volunteered t o participate in a crossover dietary intervention. The study included a baseline period and two 5-week diet periods (low- and high-folate diets) with a 3-week washout in between. The low-folate diet contained one serving of both vegetables and fruit/d, while during the high-folate diet the subjects ate at least seven servings of vegetables, berries, and citrus fruit/d. Serum and erythrocyte (RBC) folate, serum vitamin B (12), and plasma tHcy concentrations were measured at the base-line and at the end of each diet period. The mean concentrations of serum and RBC folate were 11.0 (SD 3.0) nmol/l and 412 (SD 120) nmol/l at the end of the low-folate diet and 78 (95 % CI 62, 94) % and 14 (95 % CI 8, 20) % higher in response to the high-folate diet (P< 0.001). The serum concentration of vitamin B12 remained unchanged during the intervention. The mean plasma tHcy concentration was 8.0 pmol/ at the end of the low-folate diet and decreased by 13 (95% CI 9, 18) % in response to the high-folate diet (P<0.001). In conclusion, a diet high in fresh berries, citrus fruit, and vegetables effectively increases serum and RBC folate and decreases plasma homocysteine.", "title": "British Journal of Nutrition (2003), 89, 295–301 q The Authors 2003 DOI: 10.1079/BJN2002776 Plasma homocysteine concentration is decreased by dietary intervention*" }, { "docid": "21636085", "text": "BACKGROUND Increased plasma homocysteine is associated with coronary artery disease, peripheral vascular disease and venous thrombosis. Folic acid is the most effective therapy for reducing homocysteine levels. The lowest effective supplement of folic acid is not known, particularly for the elderly who have the highest prevalence of these conditions. AIM To explore the effects of daily supplements of 0, 50, 100, 200, 400 and 600 microg folic acid on plasma homocysteine in an elderly population. \n DESIGN Randomized double-blind placebo-controlled trial. \n METHODS Participants (n=368) aged 65-75 years were randomly allocated to receive one of the treatments for 6 weeks. Plasma homocysteine was recorded after 3 weeks and 6 weeks of supplementation. \n RESULTS Only the 400 microg and 600 microg groups had significantly lower homocysteine levels compared to placebo (p=0.038 and p<0.001, respectively). Using multiple linear regression and each individual's total folic acid intake (diet plus supplement), a total daily folic acid intake of 926 microg per day would be required to ensure that 95% of the elderly population would be without cardiovascular risk from folate deficiency. DISCUSSION A daily folic acid intake of 926 microg is unlikely to be achieved by diet alone. Individual supplementation or fortification of food with folic acid will be required to reach this target.", "title": "The effect of folic acid supplementation on plasma homocysteine in an elderly population." }, { "docid": "27408104", "text": "Diet-related adaptive gene (DRAG) polymorphisms identified in specific populations are associated with chronic disorders in carriers of the adaptive alleles due to changes in dietary and lifestyle patterns in recent times. Mexico's population is comprised of Amerindians (AM) and Mestizos who have variable AM, European (EUR) and African genetic ancestry and an increased risk of nutrition-related chronic diseases. Nutritional advice based on the Mexican genome and the traditional food culture is needed to develop preventive and therapeutic strategies. Therefore, we aimed to provide a prevalence profile of several DRAG polymorphisms in the Mexican population, including Central West (CW) Mexico subpopulations. Geographic heat maps were built using ArcGIS10 (Esri, Redlands, CA, USA) software, based on the published data of the MTHFR C677T (rs1801133), ABCA1 Arg230Cys (rs9282541), APOE T388C (rs429358)/C526T (rs7412), LCT C-13910T (rs4988235) polymorphisms and AMY1 copy number variation (CNV). Also, new data obtained by allelic discrimination-real-time polymerase chain reaction (RT-PCR) assays for the MTHFR, ABCA1, and APOE polymorphisms as well as the AMY1 CNV in the CW Mexico subpopulations with different proportions of AM and EUR ancestry were included. In the CW region, the highest frequency of the MTHFR 677T, ABCA1 230C and APOE ε4 adaptive alleles was observed in the AM groups, followed by Mestizos with intermediate AM ancestry. The LCT-13910T allele frequency was highest in Mestizos-EUR but extremely low in AM, while the AMY1 diploid copy number was 6.82 ± 3.3 copies. Overall, the heat maps showed a heterogeneous distribution of the DRAG polymorphisms, in which the AM groups revealed the highest frequencies of the adaptive alleles followed by Mestizos. Given these genetic differences, genome-based nutritional advice should be tailored in a regionalized and individualized manner according to the available foods and Mexican traditional food culture that may lead to a healthier dietary pattern.", "title": "Tailoring Nutritional Advice for Mexicans Based on Prevalence Profiles of Diet-Related Adaptive Gene Polymorphisms" }, { "docid": "10557471", "text": "The aim of the present investigation was to study the effect of a dietary intervention which combined nutrition information with increased availability of vegetables, fruits and wholegrain bread. The effect of the intervention was determined by changes in the intake of vegetables, fruits, wholegrain bread and estimated nutrients. Furthermore, the study investigated whether changes in relative contribution from different food sources of folate were related to changes in the concentration of plasma total homocysteine (p-tHcy). The 5-month intervention study included 376 male recruits from the Norwegian National Guard, Vaernes (intervention group) and 105 male recruits from the Norwegian National Guard, Heggelia (control group). The study resulted in an increase in the total consumption of vegetables, fruits, berries and juice (P < 0.001) and of wholegrain bread (P < 0.001). The participants in the intervention group showed a higher increase in the intake of dietary fibre (P < 0.001) and folate (P < 0.001) compared with the control group. The relative contribution of folate intake from fruits, vegetables and wholegrain bread was higher in the intervention group compared with the control group (P < 0.001 for all). The increased intake of folate from wholegrain bread was inversely associated with a reduced concentration of p-tHcy (P = 0.017). In summary, the dietary intervention resulted in an increased intake of vegetables, fruits and wholegrain bread and a subsequent increase in folate intake from these food components. Reduction in the concentration of p-tHcy was significantly related to an increased folate intake due to an increased consumption of wholegrain bread.", "title": "Association between folate intake from different food sources in Norway and homocysteine status in a dietary intervention among young male adults." }, { "docid": "1456068", "text": "BACKGROUND Although cigarette smoking, excessive alcohol drinking, obesity, and several other well-studied unhealthy lifestyle-related factors each have been linked to the risk of multiple chronic diseases and premature death, little is known about the combined impact on mortality outcomes, in particular among Chinese and other non-Western populations. The objective of this study was to quantify the overall impact of lifestyle-related factors beyond that of active cigarette smoking and alcohol consumption on all-cause and cause-specific mortality in Chinese women. \n METHODS AND FINDINGS We used data from the Shanghai Women's Health Study, an ongoing population-based prospective cohort study in China. Participants included 71,243 women aged 40 to 70 years enrolled during 1996-2000 who never smoked or drank alcohol regularly. A healthy lifestyle score was created on the basis of five lifestyle-related factors shown to be independently associated with mortality outcomes (normal weight, lower waist-hip ratio, daily exercise, never exposed to spouse's smoking, higher daily fruit and vegetable intake). The score ranged from zero (least healthy) to five (most healthy) points. During an average follow-up of 9 years, 2,860 deaths occurred, including 775 from cardiovascular disease (CVD) and 1,351 from cancer. Adjusted hazard ratios for mortality decreased progressively with an increasing number of healthy lifestyle factors. Compared to women with a score of zero, hazard ratios (95% confidence intervals) for women with four to five factors were 0.57 (0.44-0.74) for total mortality, 0.29 (0.16-0.54) for CVD mortality, and 0.76 (0.54-1.06) for cancer mortality. The inverse association between the healthy lifestyle score and mortality was seen consistently regardless of chronic disease status at baseline. The population attributable risks for not having 4-5 healthy lifestyle factors were 33% for total deaths, 59% for CVD deaths, and 19% for cancer deaths. \n CONCLUSIONS In this first study, to our knowledge, to quantify the combined impact of lifestyle-related factors on mortality outcomes in Chinese women, a healthier lifestyle pattern-including being of normal weight, lower central adiposity, participation in physical activity, nonexposure to spousal smoking, and higher fruit and vegetable intake-was associated with reductions in total and cause-specific mortality among lifetime nonsmoking and nondrinking women, supporting the importance of overall lifestyle modification in disease prevention. Please see later in the article for the Editors' Summary.", "title": "Combined Impact of Lifestyle-Related Factors on Total and Cause-Specific Mortality among Chinese Women: Prospective Cohort Study" }, { "docid": "19278208", "text": "Background/Objectives:Folic acid supplementation has been suggested to reduce the risk of preeclampsia. However, results from few epidemiologic studies have been inconclusive. We investigated the hypothesis that folic acid supplementation and dietary folate intake before conception and during pregnancy reduce the risk of preeclampsia. Subjects/Methods:A birth cohort study was conducted in 2010–2012 at the Gansu Provincial Maternity & Child Care Hospital in Lanzhou, China. A total of 10 041 pregnant women without chronic hypertension or gestational hypertension were enrolled. Results:Compared with nonusers, folic acid supplement users had a reduced risk of preeclampsia (OR=0.61, 95% CI: 0.43–0.87). A significant dose–response of duration of use was observed among women who used folic acid supplemention during pregnancy only (P-trend=0.007). The reduced risk associated with folic acid supplement was similar for mild or severe preeclampsia and for early- or late-onset preeclampsia, although the statistical significant associations were only observed for mild (OR=0.50, 95% CI: 0.30–0.81) and late-onset (OR=0.60, 95% CI: 0.42–0.86) preeclampsia. The reduced risk associated with dietary folate intake during pregnancy was only seen for severe preeclampsia (OR=0.52, 95% CI: 0.31–0.87, for the highest quartile of dietary folate intake compared with the lowest).Conclusions:Our study results suggest that folic acid supplementation and higher dietary folate intake during pregnancy reduce the risk of preeclampsia. Future studies are needed to confirm the associations.", "title": "Folic acid supplementation and dietary folate intake, and risk of preeclampsia" }, { "docid": "36558211", "text": "OBJECTIVES To explore the different characteristics of high and low fat consumers, in particular their macronutrient intake and body mass index. \n DESIGN Reanalysis of data from the Dietary and Nutritional Survey of British Adults. Comparisons were made between groups defined as high and low fat consumers on the basis of 7-day weighed food records considered to be valid for energy intake. Individuals were classified in two ways according to the percentage energy from fat (FAT%) and the absolute amount of fat consumed (FATg). The criteria for classification of the high FAT% being > 45% (high fat) and < or = 35% (low fat). For the FATg group the threshold for the high fat group was > 138 g/day (men) and > 102 g/day (women), and for the low fat group < 85 g/day (men) and < 70 g/day (women). \n SETTING Dietary data was collected from private households in Great Britain between 1986 and 1987. SUBJECTS From the total population of 2197, individuals who were slimming, ill or had an EI: BMR of < 1.2 were excluded in order to use data which was most likely to represent habitual energy intakes. From the remaining 1240 subjects, 10.8% of this sample (6.1% of the total population) were classified as low fat consumers (76 men and 58 women) and 15.4% high fat (8.7% of the total population, 93 men and 98 women). \n MAIN OUTCOME MEASURES Macronutrient consumption and body mass index (BMI). \n RESULTS 30% of the subjects changed fat group classification when the criteria of defining high and low fat groups altered from FAT% to FATg. Nutrient intakes differed according to definition of the groups. The high fat FATg group ate significantly more of all nutrients than the low fat FATg group. However, this was not seen for the FAT% analysis, with the high fat group eating more fat and less carbohydrate. The average BMI tended to be higher in the high fat than the low fat groups, particularly in the FATg analysis. However, the high fat group contained a wide range of BMIs. Further exploration of BMI in the high fat groups, showed that age (an 11-year difference) was the only variable to distinguish individuals in the top and bottom quartiles of BMI. \n CONCLUSIONS High and low fat consumers differ according to a number of variables, and this is affected by how these groups are defined (FAT% or FATg). High fat consumers tend to have a higher BMI than low fat consumers, but not all high fat consumers are overweight or obese.", "title": "High and low fat consumers, their macronutrient intake and body mass index: further analysis of the National Diet and Nutrition Survey of British Adults." }, { "docid": "32328114", "text": "Stroke ranks as the third leading cause of death in the United States. It is now estimated that there are more than 700 000 incident strokes annually and 4.4 million stroke survivors.1 2 The economic burden of stroke was estimated by the American Heart Association to be $51 billion (direct and indirect costs) in 1999.3 Despite the advent of treatment of selected patients with acute ischemic stroke with tissue plasminogen activator and the promise of other experimental therapies, the best approach to reducing the burden of stroke remains prevention.4 5 High-risk or stroke-prone individuals can be identified and targeted for specific interventions.6 This is important because epidemiological data suggest a substantial leveling off of prior declines in stroke-related mortality and a possible increase in stroke incidence.7 8 The Stroke Council of the American Heart Association formed an ad hoc writing group to provide a clear and concise overview of the evidence regarding various established and potential stroke risk factors. The writing group was chosen based on expertise in specific subject areas, and it used literature review, reference to previously published guidelines, and expert opinion to summarize existing evidence and formulate recommendations (Table 1⇓). View this table: Table 1. Levels of Evidence and Grading of Recommendations As given in Tables 2 through 4⇓⇓⇓, risk factors or risk markers for a first stroke were classified according to potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented, less well documented).5 The tables give the estimated prevalence, population attributable risk, relative risk, and risk reduction with treatment for each factor when known. Population attributable risk reflects the proportion of ischemic strokes in the population that can be attributed to a particular risk factor and is given by the formula 100×[prevalence(relative risk−1)/prevalence(relative risk−1)+1]). …", "title": "Primary prevention of ischemic stroke: A statement for healthcare professionals from the Stroke Council of the American Heart Association." }, { "docid": "2138767", "text": "AIMS Cardiovascular disease (CVD) is now the most prevalent and debilitating disease affecting the Chinese population. The goal of the present manuscript was to analyse cardiovascular risk factors and the prevalence of non-fatal CVDs from data gathered from the 2007-2008 China National Diabetes and Metabolic Disorders Study. \n METHODS AND RESULTS A nationally representative sample of 46 239 adults, 20 years of age or older, was randomly recruited using a multistage stratified design method. Lifestyle factors, diagnosis of CVD, stroke, diabetes, and family history of each subject were collected, and an oral glucose tolerance test or a standard meal test was performed. Various non-fatal CVDs were reported by the subjects. SUDAAN software was used to perform all weighted statistical analyses, with P < 0.05 considered statistically significant. The prevalence of coronary heart disease, stroke, and CVDs was 0.74, 1.07, and 1.78% in males; and 0.51, 0.60, and 1.10% in females, respectively. The presence of CVDs increased with age in both males and females. The prevalence of being overweight or obese, hypertension, dyslipidaemia, or hyperglycaemia was 36.67, 30.09, 67.43, and 26.69% in males; and 29.77, 24.79, 63.98, and 23.62% in females, respectively. In the total sample of 46 239 patients, the prevalence of one subject having 1, 2, 3, or ≥4 of the 5 defined risk factors (i.e. smoking, overweight or obese, hypertension, dyslipidaemia, or hyperglycaemia) was 31.17, 27.38, 17.76, and 10.19%, respectively. Following adjustment for gender and age, the odds ratio of CVDs for those who had 1, 2, 3, or ≥4 risk factors was 2.36, 4.24, 4.88, and 7.22, respectively, when compared with patients with no risk factors. \n CONCLUSION Morbidity attributed to the five defined cardiovascular risk factors was high in the Chinese population, with multiple risk factors present in the same individual. Therefore, reasonable prevention strategies should be designed to attenuate the rapid rise in cardiovascular morbidity.", "title": "Prevalence of cardiovascular disease risk factor in the Chinese population: the 2007-2008 China National Diabetes and Metabolic Disorders Study." }, { "docid": "18174210", "text": "BACKGROUND The heritable haemoglobinopathy alpha(+)-thalassaemia is caused by the reduced synthesis of alpha-globin chains that form part of normal adult haemoglobin (Hb). Individuals homozygous for alpha(+)-thalassaemia have microcytosis and an increased erythrocyte count. Alpha(+)-thalassaemia homozygosity confers considerable protection against severe malaria, including severe malarial anaemia (SMA) (Hb concentration < 50 g/l), but does not influence parasite count. We tested the hypothesis that the erythrocyte indices associated with alpha(+)-thalassaemia homozygosity provide a haematological benefit during acute malaria. \n METHODS AND FINDINGS Data from children living on the north coast of Papua New Guinea who had participated in a case-control study of the protection afforded by alpha(+)-thalassaemia against severe malaria were reanalysed to assess the genotype-specific reduction in erythrocyte count and Hb levels associated with acute malarial disease. We observed a reduction in median erythrocyte count of approximately 1.5 x 10(12)/l in all children with acute falciparum malaria relative to values in community children (p < 0.001). We developed a simple mathematical model of the linear relationship between Hb concentration and erythrocyte count. This model predicted that children homozygous for alpha(+)-thalassaemia lose less Hb than children of normal genotype for a reduction in erythrocyte count of >1.1 x 10(12)/l as a result of the reduced mean cell Hb in homozygous alpha(+)-thalassaemia. In addition, children homozygous for alpha(+)-thalassaemia require a 10% greater reduction in erythrocyte count than children of normal genotype (p = 0.02) for Hb concentration to fall to 50 g/l, the cutoff for SMA. We estimated that the haematological profile in children homozygous for alpha(+)-thalassaemia reduces the risk of SMA during acute malaria compared to children of normal genotype (relative risk 0.52; 95% confidence interval [CI] 0.24-1.12, p = 0.09). \n CONCLUSIONS The increased erythrocyte count and microcytosis in children homozygous for alpha(+)-thalassaemia may contribute substantially to their protection against SMA. A lower concentration of Hb per erythrocyte and a larger population of erythrocytes may be a biologically advantageous strategy against the significant reduction in erythrocyte count that occurs during acute infection with the malaria parasite Plasmodium falciparum. This haematological profile may reduce the risk of anaemia by other Plasmodium species, as well as other causes of anaemia. Other host polymorphisms that induce an increased erythrocyte count and microcytosis may confer a similar advantage.", "title": "Increased Microerythrocyte Count in Homozygous α+-Thalassaemia Contributes to Protection against Severe Malarial Anaemia" }, { "docid": "21571708", "text": "CONTEXT Circulating concentration of lipoprotein(a) (Lp[a]), a large glycoprotein attached to a low-density lipoprotein-like particle, may be associated with risk of coronary heart disease (CHD) and stroke. \n OBJECTIVE To assess the relationship of Lp(a) concentration with risk of major vascular and nonvascular outcomes. STUDY SELECTION Long-term prospective studies that recorded Lp(a) concentration and subsequent major vascular morbidity and/or cause-specific mortality published between January 1970 and March 2009 were identified through electronic searches of MEDLINE and other databases, manual searches of reference lists, and discussion with collaborators. \n DATA EXTRACTION Individual records were provided for each of 126,634 participants in 36 prospective studies. During 1.3 million person-years of follow-up, 22,076 first-ever fatal or nonfatal vascular disease outcomes or nonvascular deaths were recorded, including 9336 CHD outcomes, 1903 ischemic strokes, 338 hemorrhagic strokes, 751 unclassified strokes, 1091 other vascular deaths, 8114 nonvascular deaths, and 242 deaths of unknown cause. Within-study regression analyses were adjusted for within-person variation and combined using meta-analysis. Analyses excluded participants with known preexisting CHD or stroke at baseline. \n DATA SYNTHESIS Lipoprotein(a) concentration was weakly correlated with several conventional vascular risk factors and it was highly consistent within individuals over several years. Associations of Lp(a) with CHD risk were broadly continuous in shape. In the 24 cohort studies, the rates of CHD in the top and bottom thirds of baseline Lp(a) distributions, respectively, were 5.6 (95% confidence interval [CI], 5.4-5.9) per 1000 person-years and 4.4 (95% CI, 4.2-4.6) per 1000 person-years. The risk ratio for CHD, adjusted for age and sex only, was 1.16 (95% CI, 1.11-1.22) per 3.5-fold higher usual Lp(a) concentration (ie, per 1 SD), and it was 1.13 (95% CI, 1.09-1.18) following further adjustment for lipids and other conventional risk factors. The corresponding adjusted risk ratios were 1.10 (95% CI, 1.02-1.18) for ischemic stroke, 1.01 (95% CI, 0.98-1.05) for the aggregate of nonvascular mortality, 1.00 (95% CI, 0.97-1.04) for cancer deaths, and 1.00 (95% CI, 0.95-1.06) for nonvascular deaths other than cancer. \n CONCLUSION Under a wide range of circumstances, there are continuous, independent, and modest associations of Lp(a) concentration with risk of CHD and stroke that appear exclusive to vascular outcomes.", "title": "Lipoprotein(a) concentration and the risk of coronary heart disease, stroke, and nonvascular mortality." }, { "docid": "6327940", "text": "Amino acids modulate the secretion of both insulin and glucagon; the composition of dietary protein therefore has the potential to influence the balance of glucagon and insulin activity. Soy protein, as well as many other vegan proteins, are higher in non-essential amino acids than most animal-derived food proteins, and as a result should preferentially favor glucagon production. Acting on hepatocytes, glucagon promotes (and insulin inhibits) cAMP-dependent mechanisms that down-regulate lipogenic enzymes and cholesterol synthesis, while up-regulating hepatic LDL receptors and production of the IGF-I antagonist IGFBP-1. The insulin-sensitizing properties of many vegan diets--high in fiber, low in saturated fat--should amplify these effects by down-regulating insulin secretion. Additionally, the relatively low essential amino acid content of some vegan diets may decrease hepatic IGF-I synthesis. Thus, diets featuring vegan proteins can be expected to lower elevated serum lipid levels, promote weight loss, and decrease circulating IGF-I activity. The latter effect should impede cancer induction (as is seen in animal studies with soy protein), lessen neutrophil-mediated inflammatory damage, and slow growth and maturation in children. In fact, vegans tend to have low serum lipids, lean physiques, shorter stature, later puberty, and decreased risk for certain prominent 'Western' cancers; a vegan diet has documented clinical efficacy in rheumatoid arthritis. Low-fat vegan diets may be especially protective in regard to cancers linked to insulin resistance--namely, breast and colon cancer--as well as prostate cancer; conversely, the high IGF-I activity associated with heavy ingestion of animal products may be largely responsible for the epidemic of 'Western' cancers in wealthy societies. Increased phytochemical intake is also likely to contribute to the reduction of cancer risk in vegans. Regression of coronary stenoses has been documented during low-fat vegan diets coupled with exercise training; such regimens also tend to markedly improve diabetic control and lower elevated blood pressure. Risk of many other degenerative disorders may be decreased in vegans, although reduced growth factor activity may be responsible for an increased risk of hemorrhagic stroke. By altering the glucagon/insulin balance, it is conceivable that supplemental intakes of key non-essential amino acids could enable omnivores to enjoy some of the health advantages of a vegan diet. An unnecessarily high intake of essential amino acids--either in the absolute sense or relative to total dietary protein--may prove to be as grave a risk factor for 'Western' degenerative diseases as is excessive fat intake.", "title": "Vegan proteins may reduce risk of cancer, obesity, and cardiovascular disease by promoting increased glucagon activity." }, { "docid": "7454794", "text": "Statins are widely used in the evidence-based lowering of cardiovascular disease (CVD) risk. The use of these drugs for secondary prevention of CVD is well founded, but their expanding use in primary prevention—in individuals without documented CVD—has raised some concerns. Firstly, evidence suggests that, in primary prevention, statins substantially decrease CVD morbidity, but only moderately reduce CVD mortality. Secondly, long-term statin use might cause adverse effects, such as incident diabetes mellitus. Thirdly, the cost-effectiveness of such a strategy is unclear, and has to be balanced against the risk of 'overmedicating' the general population. Data clearly support the use of statins for primary prevention in high-risk individuals, in whom the strategy is cost-effective and the benefits exceed the risks. Whether primary prevention is beneficial in individuals at low or moderate risk is not certain. Therefore, the prescription of statins for primary prevention should be individualized on the basis of clinical judgment, particularly for low-risk individuals. In appropriately selected individuals, statins should also be used for primary prevention of ischaemic stroke and transient ischaemic attack.", "title": "Statins in the primary prevention of cardiovascular disease" }, { "docid": "16256507", "text": "CONTEXT Adequate vitamin D status for optimum bone health has received increased recognition in recent years; however, the ideal intake is not known. Serum 25-hydroxyvitamin D is the generally accepted indicator of vitamin D status, but no universal reference level has been reached. \n OBJECTIVE To investigate the relative importance of high calcium intake and serum 25-hydroxyvitamin D for calcium homeostasis, as determined by serum intact parathyroid hormone (PTH). \n DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study of 2310 healthy Icelandic adults who were divided equally into 3 age groups (30-45 years, 50-65 years, or 70-85 years) and recruited from February 2001 to January 2003. They were administered a semi-quantitative food frequency questionnaire, which assessed vitamin D and calcium intake. Participants were further divided into groups according to calcium intake (<800 mg/d, 800-1200 mg/d, and >1200 mg/d) and serum 25-hydroxyvitamin D level (<10 ng/mL, 10-18 ng/mL, and >18 ng/mL). \n MAIN OUTCOME MEASURE Serum intact PTH as determined by calcium intake and vitamin D. RESULTS A total of 944 healthy participants completed all parts of the study. After adjusting for relevant factors, serum PTH was lowest in the group with a serum 25-hydroxyvitamin D level of more than 18 ng/mL but highest in the group with a serum 25-hydroxyvitamin D level of less than 10 ng/mL. At the low serum 25-hydroxyvitamin D level (<10 ng/mL), calcium intake of less than 800 mg/d vs more than 1200 mg/d was significantly associated with higher serum PTH (P = .04); and at a calcium intake of more than 1200 mg/d, there was a significant difference between the lowest and highest vitamin D groups (P = .04). \n CONCLUSIONS As long as vitamin D status is ensured, calcium intake levels of more than 800 mg/d may be unnecessary for maintaining calcium metabolism. Vitamin D supplements are necessary for adequate vitamin D status in northern climates.", "title": "Relationship between serum parathyroid hormone levels, vitamin D sufficiency, and calcium intake." }, { "docid": "35495268", "text": "BACKGROUND Weight loss is recommended for overweight or obese patients with type 2 diabetes on the basis of short-term studies, but long-term effects on cardiovascular disease remain unknown. We examined whether an intensive lifestyle intervention for weight loss would decrease cardiovascular morbidity and mortality among such patients. \n METHODS In 16 study centers in the United States, we randomly assigned 5145 overweight or obese patients with type 2 diabetes to participate in an intensive lifestyle intervention that promoted weight loss through decreased caloric intake and increased physical activity (intervention group) or to receive diabetes support and education (control group). The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina during a maximum follow-up of 13.5 years. \n RESULTS The trial was stopped early on the basis of a futility analysis when the median follow-up was 9.6 years. Weight loss was greater in the intervention group than in the control group throughout the study (8.6% vs. 0.7% at 1 year; 6.0% vs. 3.5% at study end). The intensive lifestyle intervention also produced greater reductions in glycated hemoglobin and greater initial improvements in fitness and all cardiovascular risk factors, except for low-density-lipoprotein cholesterol levels. The primary outcome occurred in 403 patients in the intervention group and in 418 in the control group (1.83 and 1.92 events per 100 person-years, respectively; hazard ratio in the intervention group, 0.95; 95% confidence interval, 0.83 to 1.09; P=0.51). \n CONCLUSIONS An intensive lifestyle intervention focusing on weight loss did not reduce the rate of cardiovascular events in overweight or obese adults with type 2 diabetes. (Funded by the National Institutes of Health and others; Look AHEAD ClinicalTrials.gov number, NCT00017953.).", "title": "Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes." } ]

[ { "docid": "5850219", "text": "BACKGROUND Population-based estimates of prevalence, risk distribution, and intervention uptake inform delivery of control programmes for sexually transmitted infections (STIs). We undertook the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3) after implementation of national sexual health strategies, and describe the epidemiology of four STIs in Britain (England, Scotland, and Wales) and the uptake of interventions. \n METHODS Between Sept 6, 2010 and Aug 31, 2012 , we did a probability sample survey of 15,162 women and men aged 16-74 years in Britain. Participants were interviewed with computer-assisted face-to-face and self-completion questionnaires. Urine from a sample of participants aged 16-44 years who reported at least one sexual partner over the lifetime was tested for the presence of Chlamydia trachomatis, type-specific human papillomavirus (HPV), Neisseria gonorrhoeae, and HIV antibody. We describe age-specific and sex-specific prevalences of infection and intervention uptake, in relation to demographic and behavioural factors, and explore changes since Natsal-1 (1990-91) and Natsal-2 (1999-2001). \n FINDINGS Of 8047 eligible participants invited to provide a urine sample, 4828 (60%) agreed. We excluded 278 samples, leaving 4550 (94%) participants with STI test results. Chlamydia prevalence was 1·5% (95% CI 1·1-2·0) in women and 1·1% (0·7-1·6) in men. Prevalences in individuals aged 16-24 years were 3·1% (2·2-4·3) in women and 2·3% (1·5-3·4) in men. Area-level deprivation and higher numbers of partners, especially without use of condoms, were risk factors. However, 60·4% (45·5-73·7) of chlamydia in women and 43·3% (25·9-62·5) in men was in individuals who had had one partner in the past year. Among sexually active 16-24-year-olds, 54·2% (51·4-56·9) of women and 34·6% (31·8-37·4) of men reported testing for chlamydia in the past year, with testing higher in those with more partners. High-risk HPV was detected in 15·9% (14·4-17·5) of women, similar to in Natsal-2. Coverage of HPV catch-up vaccination was 61·5% (58·2-64·7). Prevalence of HPV types 16 and 18 in women aged 18-20 years was lower in Natsal-3 than Natsal-2 (5·8% [3·9-8·6] vs 11·3% [6·8-18·2]; age-adjusted odds ratio 0·44 [0·21-0·94]). Gonorrhoea (<0·1% prevalence in women and men) and HIV (0·1% prevalence in women and 0·2% in men) were uncommon and restricted to participants with recognised high-risk factors. Since Natsal-2, substantial increases were noted in attendance at sexual health clinics (from 6·7% to 21·4% in women and from 7·7% to 19·6% in men) and HIV testing (from 8·7% to 27·6% in women and from 9·2% to 16·9% in men) in the past 5 years. \n INTERPRETATION STIs were distributed heterogeneously, requiring general and infection-specific interventions. Increases in testing and attendance at sexual health clinics, especially in people at highest risk, are encouraging. However, STIs persist both in individuals accessing and those not accessing services. Our findings provide empirical evidence to inform future sexual health interventions and services. \n FUNDING Grants from the UK Medical Research Council and the Wellcome Trust, with support from the Economic and Social Research Council and the Department of Health.", "title": "Prevalence, risk factors, and uptake of interventions for sexually transmitted infections in Britain: findings from the National Surveys of Sexual Attitudes and Lifestyles (Natsal)" } ]

[ { "docid": "3413083", "text": "BACKGROUND Following widespread rollout of chlamydia testing to non-specialist and community settings in the UK, many individuals receive a chlamydia test without being offered comprehensive STI and HIV testing. We assess sexual behaviour among testers in different settings with a view to understanding their need for other STI diagnostic services. \n METHODS A probability sample survey of the British population undertaken 2010-2012 (the third National Survey of Sexual Attitudes and Lifestyles). We analysed weighted data on chlamydia testing (past year), including location of most recent test, and diagnoses (past 5 years) from individuals aged 16-44 years reporting at least one sexual partner in the past year (4992 women, 3406 men). \n RESULTS Of the 26.8% (95% CI 25.4% to 28.2%) of women and 16.7% (15.5% to 18.1%) of men reporting a chlamydia test in the past year, 28.4% of women and 41.2% of men had tested in genitourinary medicine (GUM), 41.1% and 20.7% of women and men respectively tested in general practice (GP) and the remainder tested in other non-GUM settings. Women tested outside GUM were more likely to be older, in a relationship and to live in rural areas. Individuals tested outside GUM reported fewer risk behaviours; nevertheless, 11.0% (8.6% to 14.1%) of women and 6.8% (3.9% to 11.6%) of men tested in GP and 13.2% (10.2% to 16.8%) and 9.6% (6.5% to 13.8%) of women and men tested in other non-GUM settings reported 'unsafe sex', defined as two or more partners and no condom use with any partner in the past year. Individuals treated for chlamydia outside GUM in the past 5 years were less likely to report an HIV test in that time frame (women: 54.5% (42.7% to 65.7%) vs 74.1% (65.9% to 80.9%) in GUM; men: 23.9% (12.7% to 40.5%) vs 65.8% (56.2% to 74.3%)). \n CONCLUSIONS Most chlamydia testing occurred in non-GUM settings, among populations reporting fewer risk behaviours. However, there is a need to provide pathways to comprehensive STI care to the sizeable minority at higher risk.", "title": "Patterns of chlamydia testing in different settings and implications for wider STI diagnosis and care: a probability sample survey of the British population" }, { "docid": "829646", "text": "BACKGROUND Human papillomavirus (HPV) has been associated with cervical intraepithelial neoplasia, but the temporal relation between the infection and the neoplasia remains unclear, as does the relative importance of the specific type of HPV, other sexually transmitted diseases, and other risk factors. \n METHODS We studied prospectively a cohort of 241 women who presented for evaluation of sexually transmitted disease and had negative cervical cytologic tests. The women were followed every four months with cytologic and colposcopic examinations of the uterine cervix and tests for HPV DNA and other sexually transmitted diseases. \n RESULTS Cervical intraepithelial neoplasia grade 2 or 3 was confirmed by biopsy in 28 women. On the basis of survival analysis, the cumulative incidence of cervical intraepithelial neoplasia at two years was 28 percent among women with a positive test for HPV and 3 percent among those without detectable HPV DNA: The risk was highest among those with HPV type 16 or 18 infection (adjusted relative risk as compared with that in women without HPV infection, 11; 95 percent confidence interval, 4.6 to 26; attributable risk, 52 percent). All 24 cases of cervical intraepithelial neoplasia grade 2 or 3 among HPV-positive women were detected within 24 months after the first positive test for HPV. After adjustment for the presence of HPV infection, the development of cervical intraepithelial neoplasia was also associated with younger age at first intercourse, the presence of serum antibodies to Chlamydia trachomatis, the presence of serum antibodies to cytomegalovirus, and cervical infection with Neisseria gonorrhoeae. \n CONCLUSIONS Cervical intraepithelial neoplasia is a common and apparently early manifestation of cervical infection by HPV, particularly types 16 and 18.", "title": "A cohort study of the risk of cervical intraepithelial neoplasia grade 2 or 3 in relation to papillomavirus infection." }, { "docid": "75636923", "text": "Metabolic syndrome is diagnosed when three or more of the following criteria are met: abdominal obesity (waist circumference more than 102 cm in men and 88 cm in women); hypertriglyceridemia of 150 mg/dl or above; a high-density lipoprotein (HDL) cholesterol level less than 40 mg/dl in men or 50 mg/dl in women; blood pressure of 130/85 mm Hg or higher; or fasting glucose of at least 110 mg/dl. Individuals with metabolic syndrome are likelier than others to develop diabetes and cardiovascular disease and have increased mortality from all causes (and from cardiovascular disease in particular). The investigators attempted to determine the prevalence of the syndrome in the United States by analyzing data on 8814 men and women 20 years of age or older who took part in the Third National Health and Nutrition Examination Survey in the years 1988 to 1994. This is a cross-sectional health survey of a sample of the noninstitutionalized civilian American population. The overall age-adjusted prevalence of metabolic syndrome was 23.7%. The prevalence rose from 6.7% in persons 20 to 29 years of age to 42% in those aged 70 years and more. There was virtually no gender-related difference in prevalence rates for the combined racial groups. Metabolic syndrome was most prevalent in Mexican Americans and least prevalent in whites, African Americans, and \"others. \" Among both African Americans and Mexican Americans, women had higher prevalence rates than men. Extrapolating from age-specific prevalence rates and US census counts from the year 2000, 47 million US residents have metabolic syndrome. Considering its prevalence, it seems important to estimate the direct medical costs of metabolic syndrome. In the great majority of cases the critical causes are improper nutrition and insufficient physical activity, emphasizing the importance of controlling obesity and encouraging physical activity in the United States.", "title": "Prevalence of the Metabolic Syndrome Among Us Adults: Findings From the Third National Health and Nutrition Examination Survey" }, { "docid": "8298120", "text": "PURPOSE Glaucoma is the leading cause of global irreversible blindness. Present estimates of global glaucoma prevalence are not up-to-date and focused mainly on European ancestry populations. We systematically examined the global prevalence of primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG), and projected the number of affected people in 2020 and 2040. \n DESIGN Systematic review and meta-analysis. \n PARTICIPANTS Data from 50 population-based studies (3770 POAG cases among 140,496 examined individuals and 786 PACG cases among 112 398 examined individuals). \n METHODS We searched PubMed, Medline, and Web of Science for population-based studies of glaucoma prevalence published up to March 25, 2013. Hierarchical Bayesian approach was used to estimate the pooled glaucoma prevalence of the population aged 40-80 years along with 95% credible intervals (CrIs). Projections of glaucoma were estimated based on the United Nations World Population Prospects. Bayesian meta-regression models were performed to assess the association between the prevalence of POAG and the relevant factors. \n MAIN OUTCOME MEASURES Prevalence and projection numbers of glaucoma cases. \n RESULTS The global prevalence of glaucoma for population aged 40-80 years is 3.54% (95% CrI, 2.09-5.82). The prevalence of POAG is highest in Africa (4.20%; 95% CrI, 2.08-7.35), and the prevalence of PACG is highest in Asia (1.09%; 95% CrI, 0.43-2.32). In 2013, the number of people (aged 40-80 years) with glaucoma worldwide was estimated to be 64.3 million, increasing to 76.0 million in 2020 and 111.8 million in 2040. In the Bayesian meta-regression model, men were more likely to have POAG than women (odds ratio [OR], 1.36; 95% CrI, 1.23-1.52), and after adjusting for age, gender, habitation type, response rate, and year of study, people of African ancestry were more likely to have POAG than people of European ancestry (OR, 2.80; 95% CrI, 1.83-4.06), and people living in urban areas were more likely to have POAG than those in rural areas (OR, 1.58; 95% CrI, 1.19-2.04). \n CONCLUSIONS The number of people with glaucoma worldwide will increase to 111.8 million in 2040, disproportionally affecting people residing in Asia and Africa. These estimates are important in guiding the designs of glaucoma screening, treatment, and related public health strategies.", "title": "Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis." }, { "docid": "5151024", "text": "BACKGROUND The diagnosis of hypertension has traditionally been based on blood-pressure measurements in the clinic, but home and ambulatory measurements better correlate with cardiovascular outcome, and ambulatory monitoring is more accurate than both clinic and home monitoring in diagnosing hypertension. We aimed to compare the cost-effectiveness of different diagnostic strategies for hypertension. \n METHODS We did a Markov model-based probabilistic cost-effectiveness analysis. We used a hypothetical primary-care population aged 40 years or older with a screening blood-pressure measurement greater than 140/90 mm Hg and risk-factor prevalence equivalent to the general population. We compared three diagnostic strategies-further blood pressure measurement in the clinic, at home, and with an ambulatory monitor-in terms of lifetime costs, quality-adjusted life years, and cost-effectiveness. \n FINDINGS Ambulatory monitoring was the most cost-effective strategy for the diagnosis of hypertension for men and women of all ages. It was cost-saving for all groups (from -£56 [95% CI -105 to -10] in men aged 75 years to -£323 [-389 to -222] in women aged 40 years) and resulted in more quality-adjusted life years for men and women older than 50 years (from 0·006 [0·000 to 0·015] for women aged 60 years to 0·022 [0·012 to 0·035] for men aged 70 years). This finding was robust when assessed with a wide range of deterministic sensitivity analyses around the base case, but was sensitive if home monitoring was judged to have equal test performance to ambulatory monitoring or if treatment was judged effective irrespective of whether an individual was hypertensive. \n INTERPRETATION Ambulatory monitoring as a diagnostic strategy for hypertension after an initial raised reading in the clinic would reduce misdiagnosis and save costs. Additional costs from ambulatory monitoring are counterbalanced by cost savings from better targeted treatment. Ambulatory monitoring is recommended for most patients before the start of antihypertensive drugs. \n FUNDING National Institute for Health Research and the National Institute for Health and Clinical Excellence.", "title": "Cost-effectiveness of options for the diagnosis of high blood pressure in primary care: a modelling study." }, { "docid": "34760396", "text": "The fly Musca sorbens Wiedemann (Diptera: Muscidae) apparently transmits Chlamydia trachomatis, causing human trachoma. The literature indicates that M. sorbens breeds predominantly in isolated human faeces on the soil surface, but not in covered pit latrines. We sought to identify breeding media of M. sorbens in a rural Gambian village endemic for trachoma. Test breeding media were presented for oviposition on soil-filled buckets and monitored for adult emergence. Musca sorbens emerged from human (6/9 trials), calf (3/9), cow (3/9), dog (2/9) and goat (1/9) faeces, but not from horse faeces, composting kitchen scraps or a soil control (0/9 of each). After adjusting for mass of medium, the greatest number of flies emerged from human faeces (1426 flies/kg). Median time for emergence was 9 (inter quartile range = 8-9.75) days post-oviposition. Of all flies emerging from faeces 81% were M. sorbens. Male and female flies emerging from human faeces were significantly larger than those from other media, suggesting that they would be more fecund and live longer than smaller flies from other sources. Female flies caught from children's eyes were of a similar size to those from human faeces, but significantly larger than those from other media. We consider that human faeces are the best larval medium for M. sorbens, although some breeding also occurs in animal faeces. Removal of human faeces from the environment, through the provision of basic sanitation, is likely to greatly reduce fly density, eye contact and hence trachoma transmission, but if faeces of other animals are present M. sorbens will persist.", "title": "Human and other faeces as breeding media of the trachoma vector Musca sorbens." }, { "docid": "21616324", "text": "BACKGROUND Control of blood pressure (BP) following renal transplantation may improve allograft and patient survival. Our aims were (i) to describe the distribution of BP and the prevalence of systolic and/or diastolic hypertension in children over the first 5 years following renal transplantation and (ii) to evaluate clinical risk factors and centre-specific factors associated with hypertension in this population. \n METHODS We conducted a retrospective case note review of all current paediatric kidney transplant patients in the UK, with data collected at 6 months, 1, 2 and 5 years following transplantation in subjects with hypertension (systolic and/or diastolic BP > 95th > ) and non-hypertensive subjects BP ≤ 95th > . \n RESULTS In total, 27.3% (117/428), 27.6% (118/428), 26.0% (95/365) and 25.6% (50/195) of the patients were hypertensive (systolic and/or diastolic BP > 95th > ) at 6 months, 1, 2 and 5 years following transplantation, respectively. A total of 58.4% of the patients at 6 months, 52.8% at 1 year, 48.2% at 2 years and 48.2% at 5 years were receiving anti-hypertensive therapy, of whom 31.6-36.6% remained hypertensive. When subjects were identified as being hypertensive, on anti-hypertensive medication or had untreated hypertension (systolic and/or diastolic BP > 95th > ), 66.4, 61.0, 56.4 and 55.9% of patients were hypertensive at 6 months, 1, 2 and 5 years, respectively. In a multivariate model, odds ratios for systolic hypertension were 4.16 (deceased versus living donor), 2.65 (lowest versus highest quartile of height z-score) and 2.07 (if on anti-hypertensive; yes versus no). There was significant variation in prevalent rates of hypertension between centres (P < 0.0001) that remained significant (P = 0.003) after adjustment for all the factors in the multivariate model. \n CONCLUSIONS Control of BP after kidney transplantation remains sub-optimal in paediatric centres in the UK. Just over 25% of patients remain hypertensive 5 years following transplantation. Significant differences between centres remain unexplained and may reflect differences in assessment and management of hypertension.", "title": "Systemic arterial hypertension in children following renal transplantation: prevalence and risk factors." }, { "docid": "13734012", "text": "OBJECTIVES To carry out a further survey of archived appendix samples to understand better the differences between existing estimates of the prevalence of subclinical infection with prions after the bovine spongiform encephalopathy epizootic and to see whether a broader birth cohort was affected, and to understand better the implications for the management of blood and blood products and for the handling of surgical instruments. \n DESIGN Irreversibly unlinked and anonymised large scale survey of archived appendix samples. \n SETTING Archived appendix samples from the pathology departments of 41 UK hospitals participating in the earlier survey, and additional hospitals in regions with lower levels of participation in that survey. SAMPLE 32,441 archived appendix samples fixed in formalin and embedded in paraffin and tested for the presence of abnormal prion protein (PrP). \n RESULTS Of the 32,441 appendix samples 16 were positive for abnormal PrP, indicating an overall prevalence of 493 per million population (95% confidence interval 282 to 801 per million). The prevalence in those born in 1941-60 (733 per million, 269 to 1596 per million) did not differ significantly from those born between 1961 and 1985 (412 per million, 198 to 758 per million) and was similar in both sexes and across the three broad geographical areas sampled. Genetic testing of the positive specimens for the genotype at PRNP codon 129 revealed a high proportion that were valine homozygous compared with the frequency in the normal population, and in stark contrast with confirmed clinical cases of vCJD, all of which were methionine homozygous at PRNP codon 129. \n CONCLUSIONS This study corroborates previous studies and suggests a high prevalence of infection with abnormal PrP, indicating vCJD carrier status in the population compared with the 177 vCJD cases to date. These findings have important implications for the management of blood and blood products and for the handling of surgical instruments.", "title": "Prevalent abnormal prion protein in human appendixes after bovine spongiform encephalopathy epizootic: large scale survey" }, { "docid": "11880289", "text": "BACKGROUND Age-specific effects of mammographic screening, and the timing of such effects, are a matter of debate. The results of the UK Age trial, which compared the effect of invitation to annual mammographic screening from age 40 years with commencement of screening at age 50 years on breast cancer mortality, have been reported at 10 years of follow-up and showed no significant difference in mortality between the trial groups. Here, we report the results of the UK Age trial after 17 years of follow-up. \n METHODS Women aged 39-41 from 23 UK NHS Breast Screening Programme units years were randomly assigned by individual randomisation (1:2) to either an intervention group offered annual screening by mammography up to and including the calendar year of their 48th birthday or to a control group receiving usual medical care (invited for screening at age 50 years and every 3 years thereafter). Both groups were stratified by general practice. We compared breast cancer incidence and mortality by time since randomisation. Analyses included all women randomly assigned who could be traced with the National Health Service Central Register and who had not died or emigrated before entry. The primary outcome measures were mortality from breast cancer (defined as deaths with breast cancer coded as the underlying cause of death) and breast cancer incidence, including in-situ, invasive, and total incidence. Because there is an interest in the timing of the mortality effect, we analysed the results in different follow-up periods. This trial is registered, number ISRCTN24647151. \n FINDINGS Between Oct 14, 1990, and Sept 25, 1997, 160 921 participants were randomly assigned; 53 883 women in the intervention group and 106 953 assigned to usual medical care were included in this analysis. After a median follow-up of 17 years (IQR 16·8-18·8), the rate ratio (RR) for breast cancer mortality was 0·88 (95% CI 0·74-1·04) from tumours diagnosed during the intervention phase. A significant reduction in breast cancer mortality was noted in the intervention group compared with the control group in the first 10 years after diagnosis (RR 0·75, 0·58-0·97) but not thereafter (RR 1·02, 0·80-1·30) from tumours diagnosed during the intervention phase. The overall breast cancer incidence during 17 year follow-up was similar between the intervention group and the control group (RR 0·98, 0·93-1·04). \n INTERPRETATION Our results support an early reduction in mortality from breast cancer with annual mammography screening in women aged 40-49 years. Further data are needed to fully understand long-term effects. Cumulative incidence figures suggest at worst a small amount of overdiagnosis. \n FUNDING National Institute for Health Research Health Technology Assessment programme and the American Cancer Society. Past funding was received from the Medical Research Council, Cancer Research UK, the UK Department of Health, and the US National Cancer Institute.", "title": "Effect of mammographic screening from age 40 years on breast cancer mortality in the UK Age trial at 17 years' follow-up: a randomised controlled trial." }, { "docid": "18872233", "text": "IMPORTANCE Bariatric surgery is associated with sustained weight loss and improved physical health status for severely obese individuals. Mental health conditions may be common among patients seeking bariatric surgery; however, the prevalence of these conditions and whether they are associated with postoperative outcomes remains unknown. \n OBJECTIVE To determine the prevalence of mental health conditions among bariatric surgery candidates and recipients, to evaluate the association between preoperative mental health conditions and health outcomes following bariatric surgery, and to evaluate the association between surgery and the clinical course of mental health conditions. \n DATA SOURCES We searched PubMed, MEDLINE on OVID, and PsycINFO for studies published between January 1988 and November 2015. Study quality was assessed using an adapted tool for risk of bias; quality of evidence was rated based on GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. \n FINDINGS We identified 68 publications meeting inclusion criteria: 59 reporting the prevalence of preoperative mental health conditions (65,363 patients) and 27 reporting associations between preoperative mental health conditions and postoperative outcomes (50,182 patients). Among patients seeking and undergoing bariatric surgery, the most common mental health conditions, based on random-effects estimates of prevalence, were depression (19% [95% CI, 14%-25%]) and binge eating disorder (17% [95% CI, 13%-21%]). There was conflicting evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Neither depression nor binge eating disorder was consistently associated with differences in weight outcomes. Bariatric surgery was, however, consistently associated with postoperative decreases in the prevalence of depression (7 studies; 8%-74% decrease) and the severity of depressive symptoms (6 studies; 40%-70% decrease). \n CONCLUSIONS AND RELEVANCE Mental health conditions are common among bariatric surgery patients-in particular, depression and binge eating disorder. There is inconsistent evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Moderate-quality evidence supports an association between bariatric surgery and lower rates of depression postoperatively.", "title": "Mental Health Conditions Among Patients Seeking and Undergoing Bariatric Surgery: A Meta-analysis." }, { "docid": "2867345", "text": "BACKGROUND A sexual dimorphism exists in the incidence and prevalence of coronary artery disease--men are more commonly affected than are age-matched women. We explored the role of the Y chromosome in coronary artery disease in the context of this sexual inequity. \n METHODS We genotyped 11 markers of the male-specific region of the Y chromosome in 3233 biologically unrelated British men from three cohorts: the British Heart Foundation Family Heart Study (BHF-FHS), West of Scotland Coronary Prevention Study (WOSCOPS), and Cardiogenics Study. On the basis of this information, each Y chromosome was tracked back into one of 13 ancient lineages defined as haplogroups. We then examined associations between common Y chromosome haplogroups and the risk of coronary artery disease in cross-sectional BHF-FHS and prospective WOSCOPS. Finally, we undertook functional analysis of Y chromosome effects on monocyte and macrophage transcriptome in British men from the Cardiogenics Study. \n FINDINGS Of nine haplogroups identified, two (R1b1b2 and I) accounted for roughly 90% of the Y chromosome variants among British men. Carriers of haplogroup I had about a 50% higher age-adjusted risk of coronary artery disease than did men with other Y chromosome lineages in BHF-FHS (odds ratio 1·75, 95% CI 1·20-2·54, p=0·004), WOSCOPS (1·45, 1·08-1·95, p=0·012), and joint analysis of both populations (1·56, 1·24-1·97, p=0·0002). The association between haplogroup I and increased risk of coronary artery disease was independent of traditional cardiovascular and socioeconomic risk factors. Analysis of macrophage transcriptome in the Cardiogenics Study revealed that 19 molecular pathways showing strong differential expression between men with haplogroup I and other lineages of the Y chromosome were interconnected by common genes related to inflammation and immunity, and that some of them have a strong relevance to atherosclerosis. \n INTERPRETATION The human Y chromosome is associated with risk of coronary artery disease in men of European ancestry, possibly through interactions of immunity and inflammation. \n FUNDING British Heart Foundation; UK National Institute for Health Research; LEW Carty Charitable Fund; National Health and Medical Research Council of Australia; European Union 6th Framework Programme; Wellcome Trust.", "title": "Inheritance of coronary artery disease in men: an analysis of the role of the Y chromosome" }, { "docid": "12438901", "text": "BACKGROUND For women with oestrogen receptor (ER)-positive early breast cancer, treatment with tamoxifen for 5 years substantially reduces the breast cancer mortality rate throughout the first 15 years after diagnosis. We aimed to assess the further effects of continuing tamoxifen to 10 years instead of stopping at 5 years. \n METHODS In the worldwide Adjuvant Tamoxifen: Longer Against Shorter (ATLAS) trial, 12,894 women with early breast cancer who had completed 5 years of treatment with tamoxifen were randomly allocated to continue tamoxifen to 10 years or stop at 5 years (open control). Allocation (1:1) was by central computer, using minimisation. After entry (between 1996 and 2005), yearly follow-up forms recorded any recurrence, second cancer, hospital admission, or death. We report effects on breast cancer outcomes among the 6846 women with ER-positive disease, and side-effects among all women (with positive, negative, or unknown ER status). Long-term follow-up still continues. This study is registered, number ISRCTN19652633. \n FINDINGS Among women with ER-positive disease, allocation to continue tamoxifen reduced the risk of breast cancer recurrence (617 recurrences in 3428 women allocated to continue vs 711 in 3418 controls, p=0·002), reduced breast cancer mortality (331 deaths vs 397 deaths, p=0·01), and reduced overall mortality (639 deaths vs 722 deaths, p=0·01). The reductions in adverse breast cancer outcomes appeared to be less extreme before than after year 10 (recurrence rate ratio [RR] 0·90 [95% CI 0·79–1·02] during years 5–9 and 0·75 [0·62–0·90] in later years; breast cancer mortality RR 0·97 [0·79–1·18] during years 5–9 and 0·71 [0·58–0·88] in later years). The cumulative risk of recurrence during years 5–14 was 21·4% for women allocated to continue versus 25·1% for controls; breast cancer mortality during years 5–14 was 12·2% for women allocated to continue versus 15·0% for controls (absolute mortality reduction 2·8%). Treatment allocation seemed to have no effect on breast cancer outcome among 1248 women with ER-negative disease, and an intermediate effect among 4800 women with unknown ER status. Among all 12,894 women, mortality without recurrence from causes other than breast cancer was little affected (691 deaths without recurrence in 6454 women allocated to continue versus 679 deaths in 6440 controls; RR 0·99 [0·89–1·10]; p=0·84). For the incidence (hospitalisation or death) rates of specific diseases, RRs were as follows: pulmonary embolus 1·87 (95% CI 1·13–3·07, p=0·01 [including 0·2% mortality in both treatment groups]), stroke 1·06 (0·83–1·36), ischaemic heart disease 0·76 (0·60–0·95, p=0·02), and endometrial cancer 1·74 (1·30–2·34, p=0·0002). The cumulative risk of endometrial cancer during years 5–14 was 3·1% (mortality 0·4%) for women allocated to continue versus 1·6% (mortality 0·2%) for controls (absolute mortality increase 0·2%). \n INTERPRETATION For women with ER-positive disease, continuing tamoxifen to 10 years rather than stopping at 5 years produces a further reduction in recurrence and mortality, particularly after year 10. These results, taken together with results from previous trials of 5 years of tamoxifen treatment versus none, suggest that 10 years of tamoxifen treatment can approximately halve breast cancer mortality during the second decade after diagnosis. \n FUNDING Cancer Research UK, UK Medical Research Council, AstraZeneca UK, US Army, EU-Biomed.", "title": "Long-term effects of continuing adjuvant tamoxifen to 10 years versus stopping at 5 years after diagnosis of oestrogen receptor-positive breast cancer: ATLAS, a randomised trial" }, { "docid": "21636085", "text": "BACKGROUND Increased plasma homocysteine is associated with coronary artery disease, peripheral vascular disease and venous thrombosis. Folic acid is the most effective therapy for reducing homocysteine levels. The lowest effective supplement of folic acid is not known, particularly for the elderly who have the highest prevalence of these conditions. AIM To explore the effects of daily supplements of 0, 50, 100, 200, 400 and 600 microg folic acid on plasma homocysteine in an elderly population. \n DESIGN Randomized double-blind placebo-controlled trial. \n METHODS Participants (n=368) aged 65-75 years were randomly allocated to receive one of the treatments for 6 weeks. Plasma homocysteine was recorded after 3 weeks and 6 weeks of supplementation. \n RESULTS Only the 400 microg and 600 microg groups had significantly lower homocysteine levels compared to placebo (p=0.038 and p<0.001, respectively). Using multiple linear regression and each individual's total folic acid intake (diet plus supplement), a total daily folic acid intake of 926 microg per day would be required to ensure that 95% of the elderly population would be without cardiovascular risk from folate deficiency. DISCUSSION A daily folic acid intake of 926 microg is unlikely to be achieved by diet alone. Individual supplementation or fortification of food with folic acid will be required to reach this target.", "title": "The effect of folic acid supplementation on plasma homocysteine in an elderly population." }, { "docid": "13782317", "text": "OBJECTIVE This report presents national estimates of the use of complementary health approaches among adults in the United States across three time points. Trends in the use of selected complementary health approaches are compared for 2002, 2007, and 2012, and differences by selected demographic characteristics are also examined. \n METHODS Combined data from 88,962 adults aged 18 and over collected as part of the 2002, 2007, and 2012 National Health Interview Survey were analyzed for this report. Sample data were weighted to produce national estimates that are representative of the civilian noninstitutionalized U.S. adult population. Differences between percentages were evaluated using two-sided significance tests at the 0.05 level. \n RESULTS Although the use of individual approaches varied across the three time points, nonvitamin, nonmineral dietary supplements remained the most popular complementary health approach used. The use of yoga, tai chi, and qi gong increased linearly across the three time points; among these three approaches, yoga accounted for approximately 80% of the prevalence. The use of any complementary health approach also differed by selected sociodemographic characteristics. The most notable observed differences in use were by age and Hispanic or Latino origin and race.", "title": "Trends in the use of complementary health approaches among adults: United States, 2002-2012." }, { "docid": "45015767", "text": "BACKGROUND Adenocarcinoma of the endometrium is the most common gynecologic malignancy in the United States, accounting for approximately 36,000 diagnoses of invasive carcinoma annually. The most common histologic type, endometrioid adenocarcinoma (EC), accounts for 75-80% of patients. The objective of this work was to estimate the prevalence of concurrent carcinoma in women with a biopsy diagnosis of the precursor lesion, atypical endometrial hyperplasia (AEH). \n METHODS This prospective cohort study included women who had a community diagnosis of AEH. Diagnostic biopsy specimens were reviewed independently by three gynecologic pathologists who used International Society of Gynecologic Pathologists/World Health Organization criteria. Study participants underwent hysterectomy within 12 weeks of entry onto protocol without interval treatment. The hysterectomy slides also were reviewed by the study pathologists, and their findings were used in the subsequent analyses. \n RESULTS Between November 1998 and June 2003, 306 women were enrolled on the study. Of these, 17 women were not included in the analysis: Two patients had unreadable slides because of poor processing or insufficient tissue, 2 patients had only slides that were not endometrial, the slides for 5 patients were not available for review, and 8 of the hysterectomy specimens were excluded because they showed evidence of interval intervention, either progestin effect or ablation. In total, 289 patients were included in the current analysis. The study panel review of the AEH biopsy specimens was interpreted as follows: 74 of 289 specimens (25.6%) were diagnosed as less than AEH, 115 of 289 specimens (39.8%) were diagnosed as AEH, and 84 of 289 specimens (29.1%) were diagnosed as endometrial carcinoma. In 5.5% (16 of 289 specimens), there was no consensus on the biopsy diagnosis. The rate of concurrent endometrial carcinoma for analyzed specimens was 42.6% (123 of 289 specimens). Of these, 30.9% (38 of 123 specimens) were myoinvasive, and 10.6% (13 of 123 specimens) involved the outer 50% of the myometrium. Among the women who had hysterectomy specimens with carcinoma, 14 of 74 women (18.9%) had a study panel biopsy consensus diagnosis of less than AEH, 45 of 115 women (39.1%) had a study panel biopsy consensus diagnosis of AEH, and 54 of 84 women (64.3%) had a study panel diagnosis of carcinoma. Among women who had no consensus in their biopsy diagnosis, 10 of 16 women (62.5%) had carcinoma in their hysterectomy specimens. \n CONCLUSIONS The prevalence of endometrial carcinoma in patients who had a community hospital biopsy diagnosis of AEH was high (42.6%). When considering management strategies for women who have a biopsy diagnosis of AEH, clinicians and patients should take into account the considerable rate of concurrent carcinoma.", "title": "Concurrent endometrial carcinoma in women with a biopsy diagnosis of atypical endometrial hyperplasia: a Gynecologic Oncology Group study." }, { "docid": "1781626", "text": "This study examined the association between perceived control and several socioeconomic variables and self-rated health in seven post-communist countries (Russia, Estonia, Lithuania, Latvia, Hungary, Poland, Czech Republic). Questionnaire interviews were used to collect data on self-rated health in the last 12 months, education, marital status, perceived control based on nine questions, and material deprivation based on availability of food, clothing and heating. For each population, two ecological measures of material inequalities were available: an inequality score estimated from the survey data as the distance between the 90th and 10th percentiles of material deprivation, and Gini coefficient from published sources. Data on 5330 men and women aged 20-60 were analysed. Prevalence of poor health (worse than average) varied between 8% in Czechs and 19% in Hungarians. The age-sex-adjusted odds ratio for university vs primary education was 0.36 (0.26-0.49); odds ratios per 1 standard deviation increase in perceived control and in material deprivation were 0.58 (95% CI 0.48-0.69) and 1.51 (1.40-1.63), respectively. The odds ratio for an increase in inequality equivalent to the difference between the most and the least unequal populations was 1.49 (0.88-2.52) using the material inequality score and 1.41 (0.91-2.20) using the Gini coefficient. No indication of an effect of either inequality measure was seen after adjustment for individuals' deprivation or perceived control. The results suggest that, as in western populations, education and material deprivation are strongly related to self-rated health. Perceived control appeared statistically to mediate some of the effects of material deprivation. The non-significant effects of both ecological measures of inequality were eliminated by controlling for individuals' characteristics.", "title": "Socioeconomic factors, material inequalities, and perceived control in self-rated health: cross-sectional data from seven post-communist countries." }, { "docid": "26067999", "text": "The U.S. Preventive Services Task Force (USPSTF) makes recommendations about the effectiveness of specific preventive care services for patients without related signs or symptoms. It bases its recommendations on the evidence of both the benefits and harms of the service and an assessment of the balance. The USPSTF does not consider the costs of providing a service in this assessment. The USPSTF recognizes that clinical decisions involve more considerations than evidence alone. Clinicians should understand the evidence but individualize decision making to the specific patient or situation. Similarly, the USPSTF notes that policy and coverage decisions involve considerations in addition to the evidence of clinical benefits and harms. Summary of Recommendation and Evidence The USPSTF recommends annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years. Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery. (B recommendation) See the Clinical Considerations section for suggestions for implementation in practice. See the Figure for a summary of the recommendation and suggestions for clinical practice. Figure. Screening for lung cancer: clinical summary of U.S. Preventive Services Task Force recommendation. Appendix Table 1 describes the USPSTF grades, and Appendix Table 2 describes the USPSTF classification of levels of certainty about net benefit. Appendix Table 1. What the USPSTF Grades Mean and Suggestions for Practice Appendix Table 2. USPSTF Levels of Certainty Regarding Net Benefit Supplement. Consumer Fact Sheet. Rationale Importance Lung cancer is the third most common cancer and the leading cause of cancer-related death in the United States (1). The most important risk factor for lung cancer is smoking, which results in approximately 85% of all U.S. lung cancer cases (2). Although the prevalence of smoking has decreased, approximately 37% of U.S. adults are current or former smokers (2). The incidence of lung cancer increases with age and occurs most commonly in persons aged 55 years or older. Increasing age and cumulative exposure to tobacco smoke are the 2 most common risk factors for lung cancer. Lung cancer has a poor prognosis, and nearly 90% of persons with lung cancer die of the disease. However, early-stage nonsmall cell lung cancer (NSCLC) has a better prognosis and can be treated with surgical resection. Detection Most lung cancer cases are NSCLC, and most screening programs focus on the detection and treatment of early-stage NSCLC. Although chest radiography and sputum cytologic evaluation have been used to screen for lung cancer, LDCT has greater sensitivity for detecting early-stage cancer (3). Benefits of Detection and Early Treatment Although lung cancer screening is not an alternative to smoking cessation, the USPSTF found adequate evidence that annual screening for lung cancer with LDCT in a defined population of high-risk persons can prevent a substantial number of lung cancerrelated deaths. Direct evidence from a large, well-conducted, randomized, controlled trial (RCT) provides moderate certainty of the benefit of lung cancer screening with LDCT in this population (4). The magnitude of benefit to the person depends on that person's risk for lung cancer because those who are at highest risk are most likely to benefit. Screening cannot prevent most lung cancerrelated deaths, and smoking cessation remains essential. Harms of Detection and Early Intervention and Treatment The harms associated with LDCT screening include false-negative and false-positive results, incidental findings, overdiagnosis, and radiation exposure. False-positive LDCT results occur in a substantial proportion of screened persons; 95% of all positive results do not lead to a diagnosis of cancer. In a high-quality screening program, further imaging can resolve most false-positive results; however, some patients may require invasive procedures. The USPSTF found insufficient evidence on the harms associated with incidental findings. Overdiagnosis of lung cancer occurs, but its precise magnitude is uncertain. A modeling study performed for the USPSTF estimated that 10% to 12% of screen-detected cancer cases are overdiagnosedthat is, they would not have been detected in the patient's lifetime without screening. Radiation harms, including cancer resulting from cumulative exposure to radiation, vary depending on the age at the start of screening; the number of scans received; and the person's exposure to other sources of radiation, particularly other medical imaging. USPSTF Assessment The USPSTF concludes with moderate certainty that annual screening for lung cancer with LDCT is of moderate net benefit in asymptomatic persons who are at high risk for lung cancer based on age, total cumulative exposure to tobacco smoke, and years since quitting smoking. The moderate net benefit of screening depends on limiting screening to persons who are at high risk, the accuracy of image interpretation being similar to that found in the NLST (National Lung Screening Trial), and the resolution of most false-positive results without invasive procedures (4). Clinical Considerations Patient Population Under Consideration The risk for lung cancer increases with age and cumulative exposure to tobacco smoke and decreases with time since quitting smoking. The best evidence for the benefit of screening comes from the NLST, which enrolled adults aged 55 to 74 years who had at least a 30 pack-year smoking history and were current smokers or had quit within the past 15 years. As with all screening trials, the NLST tested a specific intervention over a finite period. Because initial eligibility extended through age 74 years and participants received 3 annual screening computed tomographic scans, the oldest participants in the trial were aged 77 years. The USPSTF used modeling studies to predict the benefits and harms of screening programs that use different screening intervals, age ranges, smoking histories, and times since quitting. A program that annually screens adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years is projected to have a reasonable balance of benefits and harms. The model assumes that persons who achieve 15 years of smoking cessation during the screening program discontinue screening. This model predicts the outcomes of continuing the screening program used in the NLST through age 80 years. Screening may not be appropriate for patients with substantial comorbid conditions, particularly those at the upper end of the screening age range. The NLST excluded persons who were unlikely to complete curative lung cancer surgery and those with medical conditions that posed a substantial risk for death during the 8-year trial. The baseline characteristics of the NLST showed a relatively healthy sample, and fewer than 10% of enrolled participants were older than 70 years (5). Persons with serious comorbid conditions may experience net harm, no net benefit, or at least substantially less net benefit. Similarly, persons who are unwilling to have curative lung surgery are unlikely to benefit from a screening program. Assessment of Risk Age, total exposure to tobacco smoke, and years since quitting smoking are important risk factors for lung cancer and were used to determine eligibility in the NLST. Other risk factors include specific occupational exposures, radon exposure, family history, and history of pulmonary fibrosis or chronic obstructive lung disease. The incidence of lung cancer is relatively low in persons younger than 50 years but increases with age, especially after age 60 years. In current and former smokers, age-specific incidence rates increase with age and cumulative exposure to tobacco smoke. Smoking cessation substantially reduces a person's risk for developing and dying of lung cancer. Among persons enrolled in the NLST, those who were at highest risk because of additional risk factors or a greater cumulative exposure to tobacco smoke experienced most of the benefit (6). A validated multivariate model showed that persons in the highest 60% of risk accounted for 88% of all deaths preventable by screening. Screening Tests Low-dose computed tomography has shown high sensitivity and acceptable specificity for the detection of lung cancer in high-risk persons. Chest radiography and sputum cytologic evaluation have not shown adequate sensitivity or specificity as screening tests. Therefore, LDCT is currently the only recommended screening test for lung cancer. Treatment Surgical resection is the current standard of care for localized NSCLC. This type of cancer is treated with surgical resection when possible and also with radiation and chemotherapy. Annual LDCT screening may not be useful for patients with life-limiting comorbid conditions or poor functional status who may not be candidates for surgery. Other Approaches to Prevention Smoking cessation is the most important intervention to prevent NSCLC. Advising smokers to stop smoking and preventing nonsmokers from being exposed to tobacco smoke are the most effective ways to decrease the morbidity and mortality associated with lung cancer. Current smokers should be informed of their continuing risk for lung cancer and offered cessation treatments. Screening with LDCT should be viewed as an adjunct to tobacco cessation interventions. Useful Resources Clinicians have many resources to help patients stop smoking. The Centers for Disease Control and Prevention has developed a Web site with many such resources, including information on tobacco quit lines, available in several languages (www.cdc.gov/tobacco/campaign/tips). Quit l", "title": "Screening for Lung Cancer: U.S. Preventive Services Task Force Recommendation Statement" }, { "docid": "7602348", "text": "BACKGROUND Preclinical diastolic dysfunction (PDD) has been defined as subjects with normal systolic function, diastolic dysfunction but no symptoms of heart failure (HF). The clinical phenotype and natural history of the syndrome remains poorly defined. This study's objective was to determine the clinical phenotype and progression to HF in a group of patients with normal systolic function and moderate or severe diastolic dysfunction as determinate by Doppler criteria without any clinical diagnosis of HF according to the Framingham criteria or any symptoms of HF, specifically dyspnoea, oedema or fatigue at the time of echocardiography. \n METHODS The authors used resources of the Mayo Clinic echocardiography database to consecutively select among patients who had an echocardiogram in 2005, a cohort with moderate or severe diastolic dysfunction by Doppler criteria and EF >or=50%. Patients could not have a diagnosis of HF, or any HF symptoms-specifically dyspnoea, oedema or fatigue-at the time of echocardiography; nor grade 3 or greater valvular dysfunction (except tricuspid valve). A total of 82 patients had their medical chart reviewed. Primary endpoint was the time to the development of (1) HF according to the Framingham criteria or (2) any symptoms of dyspnoea, oedema or fatigue. \n RESULTS The mean age of the cohort of PDD subjects was 69+/-10 years with a female (67%) preponderance. Presence of hypertension was 76%, coronary artery disease was 29%, paroxysmal atrial fibrillation was 26%, estimated creatinine clearance <60 ml/min was 51%. The 2-year cumulative probability of development of HF according to the Framingham criteria was 1.9%; however, the 2-year cumulative probability of development of any symptoms was 31.1%. The 2-year cumulative probability for cardiac hospitalisation was 21.2%. Peripheral vascular disease and hypertension were independently associated with increased likelihood for the development of symptoms. \n CONCLUSION The study demonstrates that hypertension, hyperlipidaemia, CAD and renal dysfunction are prevalent in patients with PDD. More importantly, although the progression to the development of clinical HF over 2 years was low, there was a moderate degree of progression to development of symptoms and cardiac hospitalisations over 2 years. Based on the finding that only PVD and hypertension were independently associated with the progression to the development of symptoms in subject with PDD, the authors speculate that ventricular-arterial interaction may be important to the progression of diastolic dysfunction to the development of symptoms.", "title": "Progression of preclinical diastolic dysfunction to the development of symptoms." }, { "docid": "43334921", "text": "IMPORTANCE Use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with lower risk of colorectal cancer. \n OBJECTIVE To identify common genetic markers that may confer differential benefit from aspirin or NSAID chemoprevention, we tested gene × environment interactions between regular use of aspirin and/or NSAIDs and single-nucleotide polymorphisms (SNPs) in relation to risk of colorectal cancer. \n DESIGN, SETTING, AND PARTICIPANTS Case-control study using data from 5 case-control and 5 cohort studies initiated between 1976 and 2003 across the United States, Canada, Australia, and Germany and including colorectal cancer cases (n=8634) and matched controls (n=8553) ascertained between 1976 and 2011. Participants were all of European descent. EXPOSURES Genome-wide SNP data and information on regular use of aspirin and/or NSAIDs and other risk factors. \n MAIN OUTCOMES AND MEASURES Colorectal cancer. \n RESULTS Regular use of aspirin and/or NSAIDs was associated with lower risk of colorectal cancer (prevalence, 28% vs 38%; odds ratio [OR], 0.69 [95% CI, 0.64-0.74]; P = 6.2 × 10(-28)) compared with nonregular use. In the conventional logistic regression analysis, the SNP rs2965667 at chromosome 12p12.3 near the MGST1 gene showed a genome-wide significant interaction with aspirin and/or NSAID use (P = 4.6 × 10(-9) for interaction). Aspirin and/or NSAID use was associated with a lower risk of colorectal cancer among individuals with rs2965667-TT genotype (prevalence, 28% vs 38%; OR, 0.66 [95% CI, 0.61-0.70]; P = 7.7 × 10(-33)) but with a higher risk among those with rare (4%) TA or AA genotypes (prevalence, 35% vs 29%; OR, 1.89 [95% CI, 1.27-2.81]; P = .002). In case-only interaction analysis, the SNP rs16973225 at chromosome 15q25.2 near the IL16 gene showed a genome-wide significant interaction with use of aspirin and/or NSAIDs (P = 8.2 × 10(-9) for interaction). Regular use was associated with a lower risk of colorectal cancer among individuals with rs16973225-AA genotype (prevalence, 28% vs 38%; OR, 0.66 [95% CI, 0.62-0.71]; P = 1.9 × 10(-30)) but was not associated with risk of colorectal cancer among those with less common (9%) AC or CC genotypes (prevalence, 36% vs 39%; OR, 0.97 [95% CI, 0.78-1.20]; P = .76). \n CONCLUSIONS AND RELEVANCE In this genome-wide investigation of gene × environment interactions, use of aspirin and/or NSAIDs was associated with lower risk of colorectal cancer, and this association differed according to genetic variation at 2 SNPs at chromosomes 12 and 15. Validation of these findings in additional populations may facilitate targeted colorectal cancer prevention strategies.", "title": "Association of aspirin and NSAID use with risk of colorectal cancer according to genetic variants." } ]

[ { "docid": "5850219", "text": "BACKGROUND Population-based estimates of prevalence, risk distribution, and intervention uptake inform delivery of control programmes for sexually transmitted infections (STIs). We undertook the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3) after implementation of national sexual health strategies, and describe the epidemiology of four STIs in Britain (England, Scotland, and Wales) and the uptake of interventions. \n METHODS Between Sept 6, 2010 and Aug 31, 2012 , we did a probability sample survey of 15,162 women and men aged 16-74 years in Britain. Participants were interviewed with computer-assisted face-to-face and self-completion questionnaires. Urine from a sample of participants aged 16-44 years who reported at least one sexual partner over the lifetime was tested for the presence of Chlamydia trachomatis, type-specific human papillomavirus (HPV), Neisseria gonorrhoeae, and HIV antibody. We describe age-specific and sex-specific prevalences of infection and intervention uptake, in relation to demographic and behavioural factors, and explore changes since Natsal-1 (1990-91) and Natsal-2 (1999-2001). \n FINDINGS Of 8047 eligible participants invited to provide a urine sample, 4828 (60%) agreed. We excluded 278 samples, leaving 4550 (94%) participants with STI test results. Chlamydia prevalence was 1·5% (95% CI 1·1-2·0) in women and 1·1% (0·7-1·6) in men. Prevalences in individuals aged 16-24 years were 3·1% (2·2-4·3) in women and 2·3% (1·5-3·4) in men. Area-level deprivation and higher numbers of partners, especially without use of condoms, were risk factors. However, 60·4% (45·5-73·7) of chlamydia in women and 43·3% (25·9-62·5) in men was in individuals who had had one partner in the past year. Among sexually active 16-24-year-olds, 54·2% (51·4-56·9) of women and 34·6% (31·8-37·4) of men reported testing for chlamydia in the past year, with testing higher in those with more partners. High-risk HPV was detected in 15·9% (14·4-17·5) of women, similar to in Natsal-2. Coverage of HPV catch-up vaccination was 61·5% (58·2-64·7). Prevalence of HPV types 16 and 18 in women aged 18-20 years was lower in Natsal-3 than Natsal-2 (5·8% [3·9-8·6] vs 11·3% [6·8-18·2]; age-adjusted odds ratio 0·44 [0·21-0·94]). Gonorrhoea (<0·1% prevalence in women and men) and HIV (0·1% prevalence in women and 0·2% in men) were uncommon and restricted to participants with recognised high-risk factors. Since Natsal-2, substantial increases were noted in attendance at sexual health clinics (from 6·7% to 21·4% in women and from 7·7% to 19·6% in men) and HIV testing (from 8·7% to 27·6% in women and from 9·2% to 16·9% in men) in the past 5 years. \n INTERPRETATION STIs were distributed heterogeneously, requiring general and infection-specific interventions. Increases in testing and attendance at sexual health clinics, especially in people at highest risk, are encouraging. However, STIs persist both in individuals accessing and those not accessing services. Our findings provide empirical evidence to inform future sexual health interventions and services. \n FUNDING Grants from the UK Medical Research Council and the Wellcome Trust, with support from the Economic and Social Research Council and the Department of Health.", "title": "Prevalence, risk factors, and uptake of interventions for sexually transmitted infections in Britain: findings from the National Surveys of Sexual Attitudes and Lifestyles (Natsal)" } ]

[ { "docid": "3413083", "text": "BACKGROUND Following widespread rollout of chlamydia testing to non-specialist and community settings in the UK, many individuals receive a chlamydia test without being offered comprehensive STI and HIV testing. We assess sexual behaviour among testers in different settings with a view to understanding their need for other STI diagnostic services. \n METHODS A probability sample survey of the British population undertaken 2010-2012 (the third National Survey of Sexual Attitudes and Lifestyles). We analysed weighted data on chlamydia testing (past year), including location of most recent test, and diagnoses (past 5 years) from individuals aged 16-44 years reporting at least one sexual partner in the past year (4992 women, 3406 men). \n RESULTS Of the 26.8% (95% CI 25.4% to 28.2%) of women and 16.7% (15.5% to 18.1%) of men reporting a chlamydia test in the past year, 28.4% of women and 41.2% of men had tested in genitourinary medicine (GUM), 41.1% and 20.7% of women and men respectively tested in general practice (GP) and the remainder tested in other non-GUM settings. Women tested outside GUM were more likely to be older, in a relationship and to live in rural areas. Individuals tested outside GUM reported fewer risk behaviours; nevertheless, 11.0% (8.6% to 14.1%) of women and 6.8% (3.9% to 11.6%) of men tested in GP and 13.2% (10.2% to 16.8%) and 9.6% (6.5% to 13.8%) of women and men tested in other non-GUM settings reported 'unsafe sex', defined as two or more partners and no condom use with any partner in the past year. Individuals treated for chlamydia outside GUM in the past 5 years were less likely to report an HIV test in that time frame (women: 54.5% (42.7% to 65.7%) vs 74.1% (65.9% to 80.9%) in GUM; men: 23.9% (12.7% to 40.5%) vs 65.8% (56.2% to 74.3%)). \n CONCLUSIONS Most chlamydia testing occurred in non-GUM settings, among populations reporting fewer risk behaviours. However, there is a need to provide pathways to comprehensive STI care to the sizeable minority at higher risk.", "title": "Patterns of chlamydia testing in different settings and implications for wider STI diagnosis and care: a probability sample survey of the British population" }, { "docid": "829646", "text": "BACKGROUND Human papillomavirus (HPV) has been associated with cervical intraepithelial neoplasia, but the temporal relation between the infection and the neoplasia remains unclear, as does the relative importance of the specific type of HPV, other sexually transmitted diseases, and other risk factors. \n METHODS We studied prospectively a cohort of 241 women who presented for evaluation of sexually transmitted disease and had negative cervical cytologic tests. The women were followed every four months with cytologic and colposcopic examinations of the uterine cervix and tests for HPV DNA and other sexually transmitted diseases. \n RESULTS Cervical intraepithelial neoplasia grade 2 or 3 was confirmed by biopsy in 28 women. On the basis of survival analysis, the cumulative incidence of cervical intraepithelial neoplasia at two years was 28 percent among women with a positive test for HPV and 3 percent among those without detectable HPV DNA: The risk was highest among those with HPV type 16 or 18 infection (adjusted relative risk as compared with that in women without HPV infection, 11; 95 percent confidence interval, 4.6 to 26; attributable risk, 52 percent). All 24 cases of cervical intraepithelial neoplasia grade 2 or 3 among HPV-positive women were detected within 24 months after the first positive test for HPV. After adjustment for the presence of HPV infection, the development of cervical intraepithelial neoplasia was also associated with younger age at first intercourse, the presence of serum antibodies to Chlamydia trachomatis, the presence of serum antibodies to cytomegalovirus, and cervical infection with Neisseria gonorrhoeae. \n CONCLUSIONS Cervical intraepithelial neoplasia is a common and apparently early manifestation of cervical infection by HPV, particularly types 16 and 18.", "title": "A cohort study of the risk of cervical intraepithelial neoplasia grade 2 or 3 in relation to papillomavirus infection." }, { "docid": "2867345", "text": "BACKGROUND A sexual dimorphism exists in the incidence and prevalence of coronary artery disease--men are more commonly affected than are age-matched women. We explored the role of the Y chromosome in coronary artery disease in the context of this sexual inequity. \n METHODS We genotyped 11 markers of the male-specific region of the Y chromosome in 3233 biologically unrelated British men from three cohorts: the British Heart Foundation Family Heart Study (BHF-FHS), West of Scotland Coronary Prevention Study (WOSCOPS), and Cardiogenics Study. On the basis of this information, each Y chromosome was tracked back into one of 13 ancient lineages defined as haplogroups. We then examined associations between common Y chromosome haplogroups and the risk of coronary artery disease in cross-sectional BHF-FHS and prospective WOSCOPS. Finally, we undertook functional analysis of Y chromosome effects on monocyte and macrophage transcriptome in British men from the Cardiogenics Study. \n FINDINGS Of nine haplogroups identified, two (R1b1b2 and I) accounted for roughly 90% of the Y chromosome variants among British men. Carriers of haplogroup I had about a 50% higher age-adjusted risk of coronary artery disease than did men with other Y chromosome lineages in BHF-FHS (odds ratio 1·75, 95% CI 1·20-2·54, p=0·004), WOSCOPS (1·45, 1·08-1·95, p=0·012), and joint analysis of both populations (1·56, 1·24-1·97, p=0·0002). The association between haplogroup I and increased risk of coronary artery disease was independent of traditional cardiovascular and socioeconomic risk factors. Analysis of macrophage transcriptome in the Cardiogenics Study revealed that 19 molecular pathways showing strong differential expression between men with haplogroup I and other lineages of the Y chromosome were interconnected by common genes related to inflammation and immunity, and that some of them have a strong relevance to atherosclerosis. \n INTERPRETATION The human Y chromosome is associated with risk of coronary artery disease in men of European ancestry, possibly through interactions of immunity and inflammation. \n FUNDING British Heart Foundation; UK National Institute for Health Research; LEW Carty Charitable Fund; National Health and Medical Research Council of Australia; European Union 6th Framework Programme; Wellcome Trust.", "title": "Inheritance of coronary artery disease in men: an analysis of the role of the Y chromosome" }, { "docid": "44048701", "text": "IMPORTANCE The need for surgery for the majority of patients with displaced proximal humeral fractures is unclear, but its use is increasing. \n OBJECTIVE To evaluate the clinical effectiveness of surgical vs nonsurgical treatment for adults with displaced fractures of the proximal humerus involving the surgical neck. \n DESIGN, SETTING, AND PARTICIPANTS A pragmatic, multicenter, parallel-group, randomized clinical trial, the Proximal Fracture of the Humerus Evaluation by Randomization (PROFHER) trial, recruited 250 patients aged 16 years or older (mean age, 66 years [range, 24-92 years]; 192 [77%] were female; and 249 [99.6%] were white) who presented at the orthopedic departments of 32 acute UK National Health Service hospitals between September 2008 and April 2011 within 3 weeks after sustaining a displaced fracture of the proximal humerus involving the surgical neck. Patients were followed up for 2 years (up to April 2013) and 215 had complete follow-up data. The data for 231 patients (114 in surgical group and 117 in nonsurgical group) were included in the primary analysis. \n INTERVENTIONS Fracture fixation or humeral head replacement were performed by surgeons experienced in these techniques. Nonsurgical treatment was sling immobilization. Standardized outpatient and community-based rehabilitation was provided to both groups. \n MAIN OUTCOMES AND MEASURES Primary outcome was the Oxford Shoulder Score (range, 0-48; higher scores indicate better outcomes) assessed during a 2-year period, with assessment and data collection at 6, 12, and 24 months. Sample size was based on a minimal clinically important difference of 5 points for the Oxford Shoulder Score. Secondary outcomes were the Short-Form 12 (SF-12), complications, subsequent therapy, and mortality. \n RESULTS There was no significant mean treatment group difference in the Oxford Shoulder Score averaged over 2 years (39.07 points for the surgical group vs 38.32 points for the nonsurgical group; difference of 0.75 points [95% CI, -1.33 to 2.84 points]; P = .48) or at individual time points. There were also no significant between-group differences over 2 years in the mean SF-12 physical component score (surgical group: 1.77 points higher [95% CI, -0.84 to 4.39 points]; P = .18); the mean SF-12 mental component score (surgical group: 1.28 points lower [95% CI, -3.80 to 1.23 points]; P = .32); complications related to surgery or shoulder fracture (30 patients in surgical group vs 23 patients in nonsurgical group; P = .28), requiring secondary surgery to the shoulder (11 patients in both groups), and increased or new shoulder-related therapy (7 patients vs 4 patients, respectively; P = .58); and mortality (9 patients vs 5 patients; P = .27). Ten medical complications (2 cardiovascular events, 2 respiratory events, 2 gastrointestinal events, and 4 others) occurred in the surgical group during the postoperative hospital stay. \n CONCLUSIONS AND RELEVANCE Among patients with displaced proximal humeral fractures involving the surgical neck, there was no significant difference between surgical treatment compared with nonsurgical treatment in patient-reported clinical outcomes over 2 years following fracture occurrence. These results do not support the trend of increased surgery for patients with displaced fractures of the proximal humerus. \n TRIAL REGISTRATION isrctn.com Identifier: ISRCTN50850043.", "title": "Surgical vs nonsurgical treatment of adults with displaced fractures of the proximal humerus: the PROFHER randomized clinical trial." }, { "docid": "26673492", "text": "AIMS Few studies have examined the role of gender and both area-level and individual socio-economic status (SES) as independent predictors of alcohol-related aggression (ARA) in and around licensed venues. \n METHODS The aim of the present study was to investigate the relationship between gender, area-level SES and individual SES (operationalised as occupational category) and ARA in and around licensed venues. The sample comprised 697 men and 649 women aged 16-47, who completed a patron intercept survey as part of a larger study assessing trends in harm and stakeholders' views surrounding local community level interventions in dealing with alcohol-related problems in the night-time economy. \n RESULTS Binary logistic regression analyses showed that age, gender, occupational category, area-level SES and level of intoxication at time of interview were all significant predictors of involvement in ARA. Being male doubled the odds of involvement in ARA, while age was a protective factor. Blue collar workers had more than double the odds of ARA involvement of professionals, while those living in the most socio-economically disadvantaged areas were over twice as likely to report experiencing ARA compared to those living in the most advantaged areas. However, assessment of the predictive model by gender revealed that effects of age, occupational category and area-level SES were restricted to male participants, with greater intoxication no longer predictive. \n CONCLUSIONS ARA among patrons was significantly more likely to occur among men, those in blue collar occupations, and individuals living in low SES areas, suggesting both individual and area-level disadvantage may play a role in ARA.", "title": "Demographic Risk Factors for Alcohol-Related Aggression In and Around Licensed Venues." }, { "docid": "5735492", "text": "BACKGROUND HIV disproportionately affects African-Caribbean women in Canada but the frequency and distribution of sexually transmitted infections in this community have not been previously studied. \n METHODS We recruited women based on HIV status through a Toronto community health centre. Participants completed a socio-behavioural questionnaire using Audio Computer Assisted Self-Interview (ACASI) and provided blood for syphilis, HIV, hepatitis B and C, herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), and human cytomegalovirus (CMV) serology, urine for chlamydia and gonorrhea molecular testing and vaginal secretions for bacterial vaginosis (BV) and human papillomavirus (HPV). Differences in prevalence were assessed for statistical significance using chi-square. \n RESULTS We recruited 126 HIV-positive and 291 HIV-negative women, with a median age of 40 and 31 years, respectively (p < 0.001). Active HBV infection and lifetime exposure to HBV infection were more common in HIV-positive women (4.8% vs. 0.34%, p = 0.004; and 47.6% vs. 21.2%, p < 0.0001), as was a self-reported history of HBV vaccination (66.1% vs. 44.0%, p = 0.0001). Classical STIs were rare in both groups; BV prevalence was low and did not vary by HIV status. HSV-2 infection was markedly more frequent in HIV-positive (86.3%) than HIV-negative (46.6%) women (p < 0.0001). Vaginal HPV infection was also more common in HIV-positive than in HIV-negative women (50.8% vs. 22.6%, p < 0.0001) as was infection with high-risk oncogenic HPV types (48.4% vs. 17.3%, p < 0.0001). \n CONCLUSIONS Classical STIs were infrequent in this clinic-based population of African-Caribbean women in Toronto. However, HSV-2 prevalence was higher than that reported in previous studies in the general Canadian population and was strongly associated with HIV infection, as was infection with hepatitis B and HPV.", "title": "The epidemiology of sexually transmitted co-infections in HIV-positive and HIV-negative African-Caribbean women in Toronto" }, { "docid": "42278130", "text": "PURPOSE This study examined the prevalence, correlates, and negative consequences of unmet need for personal assistance with activities of daily living (ADLs) among older adults. \n DESIGN AND METHODS The authors analyzed cross-sectional data from the 1994 National Health Interview Survey's Supplement on Aging. Data were weighted to be representative of the noninstitutionalized population aged 70 years and older. \n RESULTS Overall, 20.7% of those needing help to perform 1 or more ADLs (an estimated 629,000 persons) reported receiving inadequate assistance; for individual ADLs, the prevalence of unmet need ranged from 10.2% (eating) to 20.1% (transferring). The likelihood of having 1 or more unmet needs was associated with lower household income, multiple ADL difficulties, and living alone. Nearly half of those with unmet needs reported experiencing a negative consequence (e.g., unable to eat when hungry) as a result of their unmet need. IMPLICATIONS Greater, targeted efforts are needed to reduce the prevalence and consequences of unmet need for ADL assistance in elderly persons.", "title": "Unmet need for personal assistance with activities of daily living among older adults." }, { "docid": "15968271", "text": "OBJECTIVE Our objective is to estimate and compare the prevalence of selected adverse consequences associated with unmet need for assistance among a socioeconomically and medically vulnerable subgroup of the older adult population, those who are dually eligible for Medicare and Medicaid, with those eligible for Medicare only. \n METHOD Using data from the National Health and Aging Trends Study (NHATS), a representative survey of the older Medicare population, we calculated the prevalence of disability-related need for assistance with self-care, household tasks, and mobility activities and the prevalence of adverse consequences of unmet need by dually eligible and Medicare only status. \n RESULTS Over 2 million community-dwelling older persons experienced an adverse consequence due to unmet need for assistance with self-care (e.g., soiled their clothes), over 2 million experienced adverse consequences due to unmet need for assistance with household tasks (e.g., went without groceries), and over 3 million persons experienced at least one adverse consequence of unmet need for assistance with mobility-related activities (e.g., had to stay in bed) in the month prior to the NHATS interview. Dually eligible persons experienced higher rates of 6 of the 11 adverse consequences studied and were more likely to have at least one adverse consequence in all 3 domains than others. DISCUSSION Several care models are emerging with the goal of integrating medical care, behavioral health, and long-term services for the dual eligible population. Indicators of adverse consequences of unmet need could be used to monitor the quality and adequacy of such care systems.", "title": "The adverse consequences of unmet need among older persons living in the community: dual-eligible versus Medicare-only beneficiaries." }, { "docid": "71628189", "text": "Abstract In order to develop a program for prevention of unwanted pregnancies, we conducted a survey of contraceptive practices and reasons for contraceptive failures of 1520 women seeking abortion at eight large hospitals in Zheng Zhou City, Henan Province, P.R. China, during the period from March 1996 to May 1996. The most frequent cause of the unplanned pregnancy was contraceptive failure (71.9%); 61.7% (938) of these current pregnancies were potentially predictable by virtue of nonuse of contraception (427) or by recognition of contraceptive failures (511). Among the contraceptive failures, the proportion of condom mishaps was the highest (29.7%), next was IUD failures (23.5%), then rhythm miscalculation (15.9%). Most of abortion seekers (77.1%) used some contraceptive methods previously. But, only 19.7% of them used a contraceptive method at the first sexual intercourse. Among 1520 abortion seekers, 57.6% had used condoms previously; 50.9% of the condom users had at least one instance of condom mishap. The rhythm method had been used by 31.7% of abortion seekers previously; 59.1% of the rhythm users had at least one instance of rhythm failure. Of the 16.8% of abortion seekers who had used pills, 58.0% of them had pill failures. Among condom and pill failures, most of them (46.4% condom users and 56.0% pill users) belonged to the user failure category (poor complicance). Of those seeking abortion, 56.4% had experienced at least one instance of previous abortion; 5.3% had experienced previous abortions at least two times. Emergency contraception had been utilized by only 10 subjects prior to this current pregnancy.", "title": "Contraceptive practices of women requesting termination of pregnancy : A study from China" }, { "docid": "4828631", "text": "BACKGROUND High body-mass index (BMI) predisposes to several site-specific cancers, but a large-scale systematic and detailed characterisation of patterns of risk across all common cancers adjusted for potential confounders has not previously been undertaken. We aimed to investigate the links between BMI and the most common site-specific cancers. \n METHODS With primary care data from individuals in the Clinical Practice Research Datalink with BMI data, we fitted Cox models to investigate associations between BMI and 22 of the most common cancers, adjusting for potential confounders. We fitted linear then non-linear (spline) models; investigated effect modification by sex, menopausal status, smoking, and age; and calculated population effects. \n FINDINGS 5·24 million individuals were included; 166,955 developed cancers of interest. BMI was associated with 17 of 22 cancers, but effects varied substantially by site. Each 5 kg/m(2) increase in BMI was roughly linearly associated with cancers of the uterus (hazard ratio [HR] 1·62, 99% CI 1·56-1·69; p<0·0001), gallbladder (1·31, 1·12-1·52; p<0·0001), kidney (1·25, 1·17-1·33; p<0·0001), cervix (1·10, 1·03-1·17; p=0·00035), thyroid (1·09, 1·00-1·19; p=0·0088), and leukaemia (1·09, 1·05-1·13; p≤0·0001). BMI was positively associated with liver (1·19, 1·12-1·27), colon (1·10, 1·07-1·13), ovarian (1·09, 1.04-1.14), and postmenopausal breast cancers (1·05, 1·03-1·07) overall (all p<0·0001), but these effects varied by underlying BMI or individual-level characteristics. We estimated inverse associations with prostate and premenopausal breast cancer risk, both overall (prostate 0·98, 0·95-1·00; premenopausal breast cancer 0·89, 0·86-0·92) and in never-smokers (prostate 0·96, 0·93-0·99; premenopausal breast cancer 0·89, 0·85-0·94). By contrast, for lung and oral cavity cancer, we observed no association in never smokers (lung 0·99, 0·93-1·05; oral cavity 1·07, 0·91-1·26): inverse associations overall were driven by current smokers and ex-smokers, probably because of residual confounding by smoking amount. Assuming causality, 41% of uterine and 10% or more of gallbladder, kidney, liver, and colon cancers could be attributable to excess weight. We estimated that a 1 kg/m(2) population-wide increase in BMI would result in 3790 additional annual UK patients developing one of the ten cancers positively associated with BMI. \n INTERPRETATION BMI is associated with cancer risk, with substantial population-level effects. The heterogeneity in the effects suggests that different mechanisms are associated with different cancer sites and different patient subgroups. \n FUNDING National Institute for Health Research, Wellcome Trust, and Medical Research Council.", "title": "Body-mass index and risk of 22 specific cancers: a population-based cohort study of 5·24 million UK adults" }, { "docid": "39281140", "text": "CONTEXT Sexual dysfunction is a common adverse effect of antidepressants that frequently results in treatment noncompliance. \n OBJECTIVE To assess the efficacy of sildenafil citrate in men with sexual dysfunction associated with the use of selective and nonselective serotonin reuptake inhibitor (SRI) antidepressants. \n DESIGN, SETTING, AND PATIENTS Prospective, parallel-group, randomized, double-blind, placebo-controlled trial conducted between November 1, 2000, and January 1, 2001, at 3 US university medical centers among 90 male outpatients (mean [SD] age, 45 [8] years) with major depression in remission and sexual dysfunction associated with SRI antidepressant treatment. \n INTERVENTION Patients were randomly assigned to take sildenafil (n = 45) or placebo (n = 45) at a flexible dose starting at 50 mg and adjustable to 100 mg before sexual activity for 6 weeks. \n MAIN OUTCOME MEASURES The primary outcome measure was score on the Clinical Global Impression-Sexual Function (CGI-SF); secondary measures were scores on the International Index of Erectile Function, Arizona Sexual Experience Scale, Massachusetts General Hospital-Sexual Functioning Questionnaire, and Hamilton Rating Scale for Depression (HAM-D). \n RESULTS Among the 90 randomized patients, 93% (83/89) of patients treated per protocol took at least 1 dose of study drug and 85% (76/89) completed week 6 end-point assessments with last observation carried forward analyses. At a CGI-SF score of 2 or lower, 54.5% (24/44) of sildenafil compared with 4.4% (2/45) of placebo patients were much or very much improved (P<.001). Erectile function, arousal, ejaculation, orgasm, and overall satisfaction domain measures improved significantly in sildenafil compared with placebo patients. Mean depression scores remained consistent with remission (HAM-D score < or =10) in both groups for the study duration. \n CONCLUSION In our study, sildenafil effectively improved erectile function and other aspects of sexual function in men with sexual dysfunction associated with the use of SRI antidepressants. These improvements may allow patients to maintain adherence with effective antidepressant treatment.", "title": "Treatment of antidepressant-associated sexual dysfunction with sildenafil: a randomized controlled trial." }, { "docid": "75636923", "text": "Metabolic syndrome is diagnosed when three or more of the following criteria are met: abdominal obesity (waist circumference more than 102 cm in men and 88 cm in women); hypertriglyceridemia of 150 mg/dl or above; a high-density lipoprotein (HDL) cholesterol level less than 40 mg/dl in men or 50 mg/dl in women; blood pressure of 130/85 mm Hg or higher; or fasting glucose of at least 110 mg/dl. Individuals with metabolic syndrome are likelier than others to develop diabetes and cardiovascular disease and have increased mortality from all causes (and from cardiovascular disease in particular). The investigators attempted to determine the prevalence of the syndrome in the United States by analyzing data on 8814 men and women 20 years of age or older who took part in the Third National Health and Nutrition Examination Survey in the years 1988 to 1994. This is a cross-sectional health survey of a sample of the noninstitutionalized civilian American population. The overall age-adjusted prevalence of metabolic syndrome was 23.7%. The prevalence rose from 6.7% in persons 20 to 29 years of age to 42% in those aged 70 years and more. There was virtually no gender-related difference in prevalence rates for the combined racial groups. Metabolic syndrome was most prevalent in Mexican Americans and least prevalent in whites, African Americans, and \"others. \" Among both African Americans and Mexican Americans, women had higher prevalence rates than men. Extrapolating from age-specific prevalence rates and US census counts from the year 2000, 47 million US residents have metabolic syndrome. Considering its prevalence, it seems important to estimate the direct medical costs of metabolic syndrome. In the great majority of cases the critical causes are improper nutrition and insufficient physical activity, emphasizing the importance of controlling obesity and encouraging physical activity in the United States.", "title": "Prevalence of the Metabolic Syndrome Among Us Adults: Findings From the Third National Health and Nutrition Examination Survey" }, { "docid": "11880289", "text": "BACKGROUND Age-specific effects of mammographic screening, and the timing of such effects, are a matter of debate. The results of the UK Age trial, which compared the effect of invitation to annual mammographic screening from age 40 years with commencement of screening at age 50 years on breast cancer mortality, have been reported at 10 years of follow-up and showed no significant difference in mortality between the trial groups. Here, we report the results of the UK Age trial after 17 years of follow-up. \n METHODS Women aged 39-41 from 23 UK NHS Breast Screening Programme units years were randomly assigned by individual randomisation (1:2) to either an intervention group offered annual screening by mammography up to and including the calendar year of their 48th birthday or to a control group receiving usual medical care (invited for screening at age 50 years and every 3 years thereafter). Both groups were stratified by general practice. We compared breast cancer incidence and mortality by time since randomisation. Analyses included all women randomly assigned who could be traced with the National Health Service Central Register and who had not died or emigrated before entry. The primary outcome measures were mortality from breast cancer (defined as deaths with breast cancer coded as the underlying cause of death) and breast cancer incidence, including in-situ, invasive, and total incidence. Because there is an interest in the timing of the mortality effect, we analysed the results in different follow-up periods. This trial is registered, number ISRCTN24647151. \n FINDINGS Between Oct 14, 1990, and Sept 25, 1997, 160 921 participants were randomly assigned; 53 883 women in the intervention group and 106 953 assigned to usual medical care were included in this analysis. After a median follow-up of 17 years (IQR 16·8-18·8), the rate ratio (RR) for breast cancer mortality was 0·88 (95% CI 0·74-1·04) from tumours diagnosed during the intervention phase. A significant reduction in breast cancer mortality was noted in the intervention group compared with the control group in the first 10 years after diagnosis (RR 0·75, 0·58-0·97) but not thereafter (RR 1·02, 0·80-1·30) from tumours diagnosed during the intervention phase. The overall breast cancer incidence during 17 year follow-up was similar between the intervention group and the control group (RR 0·98, 0·93-1·04). \n INTERPRETATION Our results support an early reduction in mortality from breast cancer with annual mammography screening in women aged 40-49 years. Further data are needed to fully understand long-term effects. Cumulative incidence figures suggest at worst a small amount of overdiagnosis. \n FUNDING National Institute for Health Research Health Technology Assessment programme and the American Cancer Society. Past funding was received from the Medical Research Council, Cancer Research UK, the UK Department of Health, and the US National Cancer Institute.", "title": "Effect of mammographic screening from age 40 years on breast cancer mortality in the UK Age trial at 17 years' follow-up: a randomised controlled trial." }, { "docid": "33257464", "text": "CONTEXT Although cerebral palsy (CP) among extremely premature infants has been reported as a major morbidity outcome, there are difficulties comparing published CP rates from many sites over various birth years. \n OBJECTIVE To assess the changes in population-based, gestational age-specific prevalence rates of CP among extremely premature infants over 30 years. \n DESIGN Prospective population-based longitudinal outcome study. \n SETTING AND PARTICIPANTS In Northern Alberta, 2318 infants 20 to 27 weeks' gestational age with birth weights of 500 to 1249 g were liveborn from 1974 through 2003. By 2 years of age, 1437 (62%) had died, 23 (1%) were lost to follow-up, and 858 (37%) had received multidisciplinary neurodevelopmental assessment. \n MAIN OUTCOME MEASURE Population-based prevalence rates of CP were determined. Logistic regression with linear spline was used to assess changes in CP prevalence over time. \n RESULTS At age 2 years, 122 (14.2%) of 858 survivors had CP. This diagnosis was confirmed for each child by age 3 years or older. Among those whose gestational age was 20 to 25 weeks, population-based survival increased from 4% to 31% (P<.001), while CP prevalence per 1000 live births increased monotonically from 0 to 110 until the years 1992-1994 (P<.001) and decreased thereafter to 22 in the years 2001-2003 (P<.001). Among those whose gestational age was 26 to 27 weeks, population-based survival increased from 23% to between 75% and 80% (P<.001), while CP prevalence per 1000 live births increased monotonically from 15 to 155 until the years 1992-1994 (P<.001) and then decreased to 16 in the years 2001-2003 (P<.001). For all survivors born in the years 2001-2003, CP prevalence was 19 per 1000 live births. \n CONCLUSION Population-based CP prevalence rates for children whose gestational age was 20 to 27 weeks and whose birth weight ranged from 500 to 1249 g show steady reductions in the last decade with stable or reducing mortality, reversing trends prior to 1992-1994.", "title": "Changes in the prevalence of cerebral palsy for children born very prematurely within a population-based program over 30 years." }, { "docid": "2295434", "text": "myfood24 Is an online 24-h dietary assessment tool developed for use among British adolescents and adults. Limited information is available regarding the validity of using new technology in assessing nutritional intake among adolescents. Thus, a relative validation of myfood24 against a face-to-face interviewer-administered 24-h multiple-pass recall (MPR) was conducted among seventy-five British adolescents aged 11-18 years. Participants were asked to complete myfood24 and an interviewer-administered MPR on the same day for 2 non-consecutive days at school. Total energy intake (EI) and nutrients recorded by the two methods were compared using intraclass correlation coefficients (ICC), Bland-Altman plots (using between and within-individual information) and weighted κ to assess the agreement. Energy, macronutrients and other reported nutrients from myfood24 demonstrated strong agreement with the interview MPR data, and ICC ranged from 0·46 for Na to 0·88 for EI. There was no significant bias between the two methods for EI, macronutrients and most reported nutrients. The mean difference between myfood24 and the interviewer-administered MPR for EI was -230 kJ (-55 kcal) (95 % CI -490, 30 kJ (-117, 7 kcal); P=0·4) with limits of agreement ranging between 39 % (3336 kJ (-797 kcal)) lower and 34 % (2874 kJ (687 kcal)) higher than the interviewer-administered MPR. There was good agreement in terms of classifying adolescents into tertiles of EI (κ w =0·64). The agreement between day 1 and day 2 was as good for myfood24 as for the interviewer-administered MPR, reflecting the reliability of myfood24. myfood24 Has the potential to collect dietary data of comparable quality with that of an interviewer-administered MPR.", "title": "Agreement between an online dietary assessment tool (myfood24) and an interviewer-administered 24-h dietary recall in British adolescents aged 11-18 years." }, { "docid": "13782317", "text": "OBJECTIVE This report presents national estimates of the use of complementary health approaches among adults in the United States across three time points. Trends in the use of selected complementary health approaches are compared for 2002, 2007, and 2012, and differences by selected demographic characteristics are also examined. \n METHODS Combined data from 88,962 adults aged 18 and over collected as part of the 2002, 2007, and 2012 National Health Interview Survey were analyzed for this report. Sample data were weighted to produce national estimates that are representative of the civilian noninstitutionalized U.S. adult population. Differences between percentages were evaluated using two-sided significance tests at the 0.05 level. \n RESULTS Although the use of individual approaches varied across the three time points, nonvitamin, nonmineral dietary supplements remained the most popular complementary health approach used. The use of yoga, tai chi, and qi gong increased linearly across the three time points; among these three approaches, yoga accounted for approximately 80% of the prevalence. The use of any complementary health approach also differed by selected sociodemographic characteristics. The most notable observed differences in use were by age and Hispanic or Latino origin and race.", "title": "Trends in the use of complementary health approaches among adults: United States, 2002-2012." }, { "docid": "8298120", "text": "PURPOSE Glaucoma is the leading cause of global irreversible blindness. Present estimates of global glaucoma prevalence are not up-to-date and focused mainly on European ancestry populations. We systematically examined the global prevalence of primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG), and projected the number of affected people in 2020 and 2040. \n DESIGN Systematic review and meta-analysis. \n PARTICIPANTS Data from 50 population-based studies (3770 POAG cases among 140,496 examined individuals and 786 PACG cases among 112 398 examined individuals). \n METHODS We searched PubMed, Medline, and Web of Science for population-based studies of glaucoma prevalence published up to March 25, 2013. Hierarchical Bayesian approach was used to estimate the pooled glaucoma prevalence of the population aged 40-80 years along with 95% credible intervals (CrIs). Projections of glaucoma were estimated based on the United Nations World Population Prospects. Bayesian meta-regression models were performed to assess the association between the prevalence of POAG and the relevant factors. \n MAIN OUTCOME MEASURES Prevalence and projection numbers of glaucoma cases. \n RESULTS The global prevalence of glaucoma for population aged 40-80 years is 3.54% (95% CrI, 2.09-5.82). The prevalence of POAG is highest in Africa (4.20%; 95% CrI, 2.08-7.35), and the prevalence of PACG is highest in Asia (1.09%; 95% CrI, 0.43-2.32). In 2013, the number of people (aged 40-80 years) with glaucoma worldwide was estimated to be 64.3 million, increasing to 76.0 million in 2020 and 111.8 million in 2040. In the Bayesian meta-regression model, men were more likely to have POAG than women (odds ratio [OR], 1.36; 95% CrI, 1.23-1.52), and after adjusting for age, gender, habitation type, response rate, and year of study, people of African ancestry were more likely to have POAG than people of European ancestry (OR, 2.80; 95% CrI, 1.83-4.06), and people living in urban areas were more likely to have POAG than those in rural areas (OR, 1.58; 95% CrI, 1.19-2.04). \n CONCLUSIONS The number of people with glaucoma worldwide will increase to 111.8 million in 2040, disproportionally affecting people residing in Asia and Africa. These estimates are important in guiding the designs of glaucoma screening, treatment, and related public health strategies.", "title": "Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis." }, { "docid": "5548081", "text": "CONTEXT Some studies have inferred that an epidemic of Kaposi sarcoma-associated herpesvirus (KSHV) infection in homosexual men in the United States occurred concurrently with that of human immunodeficiency virus (HIV), but there have been no direct measurements of KSHV prevalence at the beginning of the HIV epidemic. \n OBJECTIVES To determine the prevalence of KSHV infection in homosexual men in San Francisco, Calif, at the beginning of the HIV epidemic in 1978 and 1979 and to examine changes in prevalence of KSHV at time points from 1978 through 1996 in light of changes in sexual behavior. \n DESIGN, SETTING, AND PARTICIPANTS Analysis of a clinic-based sample (n = 398) derived from the San Francisco City Clinic Cohort (ages 18-66 years) (n = 2666 for analyses herein) and from population-based samples from the San Francisco Men's Health Study (MHS) (ages 25-54 years) (n = 825 and 252) and the San Francisco Young Men's Health Study (YMHS) (ages 18-29 years) (n = 428-976, and 557); behavioral studies were longitudinal and KSHV prevalence studies were cross-sectional. \n MAIN OUTCOME MEASURES Antibodies against KSHV and HIV; sexual behaviors. \n RESULTS The prevalence of KSHV infection in 1978 and 1979 was 26.5% of 235 (a random sample) overall (weighted for HIV infection) vs 6.9% (128/1842) for HIV in the San Francisco City Clinic Cohort sample. The prevalence of KSHV infection remained essentially unchanged between an MHS sample of 252 in 1984 and 1985 (29.6%) and a YMHS sample of 557 in 1995 and 1996 (26.4%), while HIV prevalence dropped from 49.5% of 825 in 1984 and 1985 (MHS) to 17.6% of 428 in 1992 and 1993 (YMHS). The proportion of men practicing unprotected receptive anal intercourse with 1 or more partners declined from 54% to 11% during the 1984 through 1993 period (MHS) with similar though slightly higher values in the YMHS in 1992 and 1993; whereas for unprotected oral intercourse it ranged between 60% and 90% in the 1984 through 1996 period (MHS and YMHS). \n CONCLUSIONS Infection with KSHV was already highly prevalent in homosexual men when the HIV epidemic began in San Francisco, and its prevalence has been maintained at a nearly constant level. Any declines in the incidence of Kaposi sarcoma do not appear to be caused by a decline in KSHV transmission.", "title": "Prevalence of Kaposi sarcoma-associated herpesvirus infection in homosexual men at beginning of and during the HIV epidemic." }, { "docid": "13900610", "text": "BACKGROUND Self-harm and suicide are common in prisoners, yet robust information on the full extent and characteristics of people at risk of self-harm is scant. Furthermore, understanding how frequently self-harm is followed by suicide, and in which prisoners this progression is most likely to happen, is important. We did a case-control study of all prisoners in England and Wales to ascertain the prevalence of self-harm in this population, associated risk factors, clustering effects, and risk of subsequent suicide after self-harm. \n METHODS Records of self-harm incidents in all prisons in England and Wales were gathered routinely between January, 2004, and December, 2009. We did a case-control comparison of prisoners who self-harmed and those who did not between January, 2006, and December, 2009. We also used a Bayesian approach to look at clustering of people who self-harmed. Prisoners who self-harmed and subsequently died by suicide in prison were compared with other inmates who self-harmed. \n FINDINGS 139,195 self-harm incidents were recorded in 26,510 individual prisoners between 2004 and 2009; 5-6% of male prisoners and 20-24% of female inmates self-harmed every year. Self-harm rates were more than ten times higher in female prisoners than in male inmates. Repetition of self-harm was common, particularly in women and teenage girls, in whom a subgroup of 102 prisoners accounted for 17,307 episodes. In both sexes, self-harm was associated with younger age, white ethnic origin, prison type, and a life sentence or being unsentenced; in female inmates, committing a violent offence against an individual was also a factor. Substantial evidence was noted of clustering in time and location of prisoners who self-harmed (adjusted intra-class correlation 0·15, 95% CI 0·11-0·18). 109 subsequent suicides in prison were reported in individuals who self-harmed; the risk was higher in those who self-harmed than in the general prison population, and more than half the deaths occurred within a month of self-harm. Risk factors for suicide after self-harm in male prisoners were older age and a previous self-harm incident of high or moderate lethality; in female inmates, a history of more than five self-harm incidents within a year was associated with subsequent suicide. \n INTERPRETATION The burden of self-harm in prisoners is substantial, particularly in women. Self-harm in prison is associated with subsequent suicide in this setting. Prevention and treatment of self-harm in prisoners is an essential component of suicide prevention in prisons. \n FUNDING Wellcome Trust, National Institute for Health Research, National Offender Management Service, and Department of Health.", "title": "Self-harm in prisons in England and Wales: an epidemiological study of prevalence, risk factors, clustering, and subsequent suicide" } ]

[ { "docid": "22080671", "text": "Previous studies investigating the role of smooth muscle cells (SMCs) and macrophages in the pathogenesis of atherosclerosis have provided controversial results owing to the use of unreliable methods for clearly identifying each of these cell types. Here, using Myh11-CreERT2 ROSA floxed STOP eYFP Apoe−/− mice to perform SMC lineage tracing, we find that traditional methods for detecting SMCs based on immunostaining for SMC markers fail to detect >80% of SMC-derived cells within advanced atherosclerotic lesions. These unidentified SMC-derived cells exhibit phenotypes of other cell lineages, including macrophages and mesenchymal stem cells (MSCs). SMC-specific conditional knockout of Krüppel-like factor 4 (Klf4) resulted in reduced numbers of SMC-derived MSC- and macrophage-like cells, a marked reduction in lesion size, and increases in multiple indices of plaque stability, including an increase in fibrous cap thickness as compared to wild-type controls. On the basis of in vivo KLF4 chromatin immunoprecipitation–sequencing (ChIP-seq) analyses and studies of cholesterol-treated cultured SMCs, we identified >800 KLF4 target genes, including many that regulate pro-inflammatory responses of SMCs. Our findings indicate that the contribution of SMCs to atherosclerotic plaques has been greatly underestimated, and that KLF4-dependent transitions in SMC phenotype are critical in lesion pathogenesis.", "title": "KLF4-dependent phenotypic modulation of smooth muscle cells has a key role in atherosclerotic plaque pathogenesis" } ]

[ { "docid": "6397191", "text": "Endothelin-1 (ET-1) is the predominant endothelin isopeptide generated by the vascular wall and therefore appears to be the most important peptide involved in regulation of cardiovascular events. Many pathologic conditions are associated with elevations of ET-1 in the blood vessel wall. Because these conditions are often cytokine driven, we examined the effects of a mixture of cytokines on ET-1 production in human vascular smooth muscle cells (VSMCs) derived from internal mammary artery and saphenous vein (SV). Incubation of IMA and SV VSMCs with tumor necrosis factor-alpha (10 ng/ml) and interferon-gamma (1000 U/ml) in combination for up to 48 h markedly elevated the expression of mRNA for prepro-ET-1 and the release of ET-1 into the culture medium. This cytokine-stimulated release of ET-1 was inhibited by a series of dual endothelin-converting enzyme (ECE)/neutral endopeptidase inhibitors, phosphoramidon, CGS 26303, and CGS 26393, with an accompanying increase in big ET-1 release but with no effect on expression of mRNA for prepro-ET-1. These same compounds were 10 times more potent at inhibiting the conversion of exogenously applied big ET-1 to ET-1. ECE-1b/c mRNA is present in SV VSMCs, however no ECE-1a is present in these cells. Thus VSMCs most probably contain, like endothelial cells, an intracellular ECE responsible for the endogenous synthesis of ET-1. Under the influence of pro-inflammatory mediators the vascular smooth muscle can therefore become an important site of ET-1 production, as has already been established for the dilator mediators nitric oxide, prostaglandin I2, and prostaglandin E2.", "title": "Endothelin-1 is induced by cytokines in human vascular smooth muscle cells: evidence for intracellular endothelin-converting enzyme." }, { "docid": "29509926", "text": "Membrane cholesterol modulates a variety of cell signaling pathways and functions. While cholesterol depletion by high-density lipoproteins (HDLs) has potent anti-inflammatory effects in various cell types, its effects on inflammatory responses in macrophages remain elusive. Here we show overt pro-inflammatory effects of HDL-mediated passive cholesterol depletion and lipid raft disruption in murine and human primary macrophages in vitro. These pro-inflammatory effects were confirmed in vivo in peritoneal macrophages from apoA-I transgenic mice, which have elevated HDL levels. In line with these findings, the innate immune responses required for clearance of P. aeruginosa bacterial infection in lung were compromised in mice with low HDL levels. Expression analysis, ChIP-PCR, and combinatorial pharmacological and genetic intervention studies unveiled that both native and reconstituted HDL enhance Toll-like-receptor-induced signaling by activating a PKC-NF-κB/STAT1-IRF1 axis, leading to increased inflammatory cytokine expression. HDL's pro-inflammatory activity supports proper functioning of macrophage immune responses.", "title": "High-Density Lipoproteins Exert Pro-inflammatory Effects on Macrophages via Passive Cholesterol Depletion and PKC-NF-κB/STAT1-IRF1 Signaling." }, { "docid": "6144969", "text": "Virally induced inflammatory responses, beta cell destruction and release of beta cell autoantigens may lead to autoimmune reactions culminating in type 1 diabetes. Therefore, viral capability to induce beta cell death and the nature of virus-induced immune responses are among key determinants of diabetogenic viruses. We hypothesised that enterovirus infection induces a specific gene expression pattern that results in islet destruction and that such a host response pattern is not shared among all enterovirus infections but varies between virus strains. The changes in global gene expression and secreted cytokine profiles induced by lytic or benign enterovirus infections were studied in primary human pancreatic islet using DNA microarrays and viral strains either isolated at the clinical onset of type 1 diabetes or capable of causing a diabetes-like condition in mice. The expression of pro-inflammatory cytokine genes (IL-1-α, IL-1-β and TNF-α) that also mediate cytokine-induced beta cell dysfunction correlated with the lytic potential of a virus. Temporally increasing gene expression levels of double-stranded RNA recognition receptors, antiviral molecules, cytokines and chemokines were detected for all studied virus strains. Lytic coxsackievirus B5 (CBV-5)-DS infection also downregulated genes involved in glycolysis and insulin secretion. The results suggest a distinct, virus-strain-specific, gene expression pattern leading to pancreatic islet destruction and pro-inflammatory effects after enterovirus infection. However, neither viral replication nor cytotoxic cytokine production alone are sufficient to induce necrotic cell death. More likely the combined effect of these and possibly cellular energy depletion lie behind the enterovirus-induced necrosis of islets.", "title": "Enterovirus-induced gene expression profile is critical for human pancreatic islet destruction" }, { "docid": "2260571", "text": "RATIONALE Matrix vesicles (MVs), secreted by vascular smooth muscle cells (VSMCs), form the first nidus for mineralization and fetuin-A, a potent circulating inhibitor of calcification, is specifically loaded into MVs. However, the processes of fetuin-A intracellular trafficking and MV biogenesis are poorly understood. \n OBJECTIVE The objective of this study is to investigate the regulation, and role, of MV biogenesis in VSMC calcification. \n METHODS AND RESULTS Alexa488-labeled fetuin-A was internalized by human VSMCs, trafficked via the endosomal system, and exocytosed from multivesicular bodies via exosome release. VSMC-derived exosomes were enriched with the tetraspanins CD9, CD63, and CD81, and their release was regulated by sphingomyelin phosphodiesterase 3. Comparative proteomics showed that VSMC-derived exosomes were compositionally similar to exosomes from other cell sources but also shared components with osteoblast-derived MVs including calcium-binding and extracellular matrix proteins. Elevated extracellular calcium was found to induce sphingomyelin phosphodiesterase 3 expression and the secretion of calcifying exosomes from VSMCs in vitro, and chemical inhibition of sphingomyelin phosphodiesterase 3 prevented VSMC calcification. In vivo, multivesicular bodies containing exosomes were observed in vessels from chronic kidney disease patients on dialysis, and CD63 was found to colocalize with calcification. Importantly, factors such as tumor necrosis factor-α and platelet derived growth factor-BB were also found to increase exosome production, leading to increased calcification of VSMCs in response to calcifying conditions. \n CONCLUSIONS This study identifies MVs as exosomes and shows that factors that can increase exosome release can promote vascular calcification in response to environmental calcium stress. Modulation of the exosome release pathway may be as a novel therapeutic target for prevention.", "title": "Vascular smooth muscle cell calcification is mediated by regulated exosome secretion." }, { "docid": "343052", "text": "Curcumin, a major component of turmeric, has been shown to exhibit anti-oxidant and anti-inflammatory activities. The present study was performed to determine whether curcumin is efficacious against both collagen-induced arthritis (CIA) in mice and IL-1beta-induced activation in fibroblast-like synoviocytes (FLSs). DBA/1 mice were immunized with bovine type II collagen (CII) and treated with curcumin every other day for 2weeks after the initial immunization. For arthritis, we evaluated the incidence of disease and used an arthritis index based on paw thickness. In vitro proliferation of CII- or concanavalin A-induced splenic T cells was examined using IFN-gamma production. Pro-inflammatory cytokines TNF-alpha and IL-1beta were examined in the mouse ankle joint and serum IgG1 and IgG2a isotypes were analyzed. The expression levels of prostaglandin E(2) (PGE(2)), cyclooxygenase-2 (COX-2), and matrix metalloproteinases (MMPs) in human FLSs were also determined. The results showed that compared with untreated CIA mice, curcumin-treated mice downregulated clinical arthritis score, the proliferation of splenic T cells, expression levels of TNF-alpha and IL-1beta in the ankle joint, and expression levels of IgG2a in serum. Additionally, by altering nuclear factor (NF)-kappaB transcription activity in FLSs, curcumin inhibited PGE(2) production, COX-2 expression, and MMP secretion. These results suggest that curcumin can effectively suppress inflammatory response by inhibiting pro-inflammatory mediators and regulating humoral and cellular immune responses.", "title": "Curcumin attenuates inflammatory response in IL-1beta-induced human synovial fibroblasts and collagen-induced arthritis in mouse model." }, { "docid": "25148216", "text": "Several members of the Kruppel-like factor (KLF) family of transcription factors play important roles in differentiation, survival, and trafficking of blood and immune cell types. We demonstrate in this study that hematopoietic cells from KLF4(-/-) fetal livers (FL) contained normal numbers of functional hematopoietic progenitor cells, were radioprotective, and performed as well as KLF4(+/+) cells in competitive repopulation assays. However, hematopoietic \"KLF4(-/-) chimeras\" generated by transplantation of KLF4(-/-) fetal livers cells into lethally irradiated wild-type mice completely lacked circulating inflammatory (CD115(+)Gr1(+)) monocytes, and had reduced numbers of resident (CD115(+)Gr1(-)) monocytes. Although the numbers and function of peritoneal macrophages were normal in KLF4(-/-) chimeras, bone marrow monocytic cells from KLF4(-/-) chimeras expressed lower levels of key trafficking molecules and were more apoptotic. Thus, our in vivo loss-of-function studies demonstrate that KLF4, previously shown to mediate proinflammatory signaling in human macrophages in vitro, is essential for differentiation of mouse inflammatory monocytes, and is involved in the differentiation of resident monocytes. In addition, inducible expression of KLF4 in the HL60 human acute myeloid leukemia cell line stimulated monocytic differentiation and enhanced 12-O-tetradecanoylphorbol 13-acetate induced macrophage differentiation, but blocked all-trans-retinoic acid induced granulocytic differentiation of HL60 cells. The inflammation-selective effects of loss-of-KLF4 and the gain-of-KLF4-induced monocytic differentiation in HL60 cells identify KLF4 as a key regulator of monocytic differentiation and a potential target for translational immune modulation.", "title": "Kruppel-like factor 4 is essential for inflammatory monocyte differentiation in vivo." }, { "docid": "52865789", "text": "OBJECTIVE IL-15 is an inflammatory cytokine secreted by many cell types. IL-15 is also produced during physical exercise by skeletal muscle and has been reported to reduce weight gain in mice. Contrarily, our findings on IL-15 knockout (KO) mice indicate that IL-15 promotes obesity. The aim of this study is to investigate the mechanisms underlying the pro-obesity role of IL-15 in adipose tissues. \n METHODS Control and IL-15 KO mice were maintained on high fat diet (HFD) or normal control diet. After 16 weeks, body weight, adipose tissue and skeletal mass, serum lipid levels and gene/protein expression in the adipose tissues were evaluated. The effect of IL-15 on thermogenesis and oxygen consumption was also studied in primary cultures of adipocytes differentiated from mouse preadipocyte and human stem cells. \n RESULTS Our results show that IL-15 deficiency prevents diet-induced weight gain and accumulation of lipids in visceral and subcutaneous white and brown adipose tissues. Gene expression analysis also revealed elevated expression of genes associated with adaptive thermogenesis in the brown and subcutaneous adipose tissues of IL-15 KO mice. Accordingly, oxygen consumption was increased in the brown adipocytes from IL-15 KO mice. In addition, IL-15 KO mice showed decreased expression of pro-inflammatory mediators in their adipose tissues. \n CONCLUSIONS Absence of IL-15 results in decreased accumulation of fat in the white adipose tissues and increased lipid utilization via adaptive thermogenesis. IL-15 also promotes inflammation in adipose tissues that could sustain chronic inflammation leading to obesity-associated metabolic syndrome.", "title": "Deficiency of Interleukin-15 Confers Resistance to Obesity by Diminishing Inflammation and Enhancing the Thermogenic Function of Adipose Tissues" }, { "docid": "45449835", "text": "Myelin-directed autoimmunity is considered to play a key role in the pathogenesis of multiple sclerosis (MS). Increased production of both pro- and anti-inflammatory cytokines is a common finding in MS. Interleukin-17 (IL-17) is a recently described cytokine produced in humans almost exclusively by activated memory T cells, which can induce the production of proinflammatory cytokines and chemokines from parenchymal cells and macrophages. In situ hybridisation with synthetic oligonucleotide probes was adopted to detect and enumerate IL-17 mRNA expressing mononuclear cells (MNC) in blood and cerebrospinal fluid (CSF) from patients with MS and control individuals. Numbers of IL-17 mRNA expressing blood MNC were higher in patients with MS and acute aseptic meningoencephalitis (AM) compared to healthy individuals. Higher numbers of IL-17 mRNA expressing blood MNC were detected in MS patients examined during clinical exacerbation compared to remission. Patients with MS had higher numbers of IL-17 mRNA expressing MNC in CSF compared to blood. This increase in numbers of IL-17 mRNA expressing MNC in CSF was not observed in patients with AM. Our results thus demonstrate increased numbers of IL-17 mRNA expressing MNC in MS with higher numbers in CSF than blood, and with the highest numbers in blood during clinical exacerbations.", "title": "Interleukin-17 mRNA expression in blood and CSF mononuclear cells is augmented in multiple sclerosis." }, { "docid": "364522", "text": "OBJECTIVES Calcific aortic valve (AV) disease is known to be an inflammation-related process. High-mobility group box-1 (HMGB1) protein and Toll-like receptor 4 (TLR4) have been reported to participate in several inflammatory diseases. The purpose of the present study was to determine whether the HMGB1-TLR4 axis is involved in calcific AV disease, and to evaluate the effect of HMGB1, and its potential mechanisms, on the pro-osteogenic phenotype change of valvular interstitial cells (VICs). \n METHODS Expression of HMGB1 and TLR4 in human calcific AVs was evaluated using immunohistochemical staining and immunoblotting. Cultured VICs were used as an in vitro model. The VICs were stimulated with HMGB1 for analysis, with versus without TLR4 small interfering ribonucleic acid (siRNA), c-Jun N-terminal kinase mitogen-activated protein kinase (JNK MAPK), and nuclear factor kappa-B (NF-κB) inhibitors. \n RESULTS Enhanced accumulation of HMGB1 and TLR4 was observed in calcific valves. Moreover, we found that HMGB1 induced high levels of pro-inflammatory cytokine production and promoted the osteoblastic differentiation and calcification of VICs. In addition, HMGB1 induced phosphorylation of JNK MAPK and NF-κB. However, these effects were markedly suppressed by siRNA silencing of TLR4. In addition, blockade of JNK MAPK and NF-κB phosphorylation prohibited HMGB1-induced production of pro-osteogenic factors, and mineralization of VICs. \n CONCLUSIONS The HMGB1 protein may promote osteoblastic differentiation and calcification of VICs, through the TLR4-JNK-NF-κB signaling pathway.", "title": "High-mobility group box-1 protein induces osteogenic phenotype changes in aortic valve interstitial cells." }, { "docid": "8446259", "text": "Background: Vascular calcification (VC), in which vascular smooth muscle cells (VSMCs) undergo a phenotypic transformation into osteoblast-like cells, is one of the emergent risk factors for the accelerated atherosclerosis process characteristic of chronic kidney disease (CKD). Phosphate is an important regulator of VC. Methods: The expression of different smooth muscle cell or osteogenesis markers in response to high concentrations of phosphate or exogenous bone morphogenetic protein 2 (BMP-2) was examined by qRT-PCR and western blotting in rat VSMCs. Osteocalcin secretion was measured by radioimmunoassay. Differentiation and calcification of VSMCs were examined by alkaline phosphatase (ALP) activity assay and Alizarin staining. Short hairpin RNA-mediated silencing of β-catenin was performed to examine the involvement of Wnt/β-catenin signaling in VSMC calcification and osteoblastic differentiation induced by high phosphate or BMP-2. Apoptosis was determined by TUNEL assay and immunofluorescence imaging. Results: BMP-2 serum levels were significantly higher in CKD patients than in controls. High phosphate concentrations and BMP-2 induced VSMC apoptosis and upregulated the expression of β-catenin, Msx2, Runx2 and the phosphate cotransporter Pit1, whereas a BMP-2 neutralization antibody reversed these effects. Knockdown of β-catenin abolished the effect of high phosphate and BMP-2 on VSMC apoptosis and calcification. Conclusions: BMP-2 plays a crucial role in calcium deposition in VSMCs and VC in CKD patients via a mechanism involving the Wnt/β-catenin pathway.", "title": "Vascular Calcification in Chronic Kidney Disease is Induced by Bone Morphogenetic Protein-2 via a Mechanism Involving the Wnt/β-Catenin Pathway" }, { "docid": "16863359", "text": "Inflammasomes are multiprotein complexes that link pathogen recognition and cellular stress to the processing of the proinflammatory cytokine interleukin-1β (IL-1β). Whereas inflammasome-mediated activation is heavily studied in hematopoietic macrophages and dendritic cells, much less is known about microglia, resident tissue macrophages of the brain that originate from a distinct progenitor. To directly compare inflammasome-mediated activation in different types of macrophages, we isolated primary microglia and hematopoietic macrophages from adult, healthy rhesus macaques. We analyzed the expression profile of NOD (nucleotide-binding oligomerization domain)-like receptors, adaptor proteins, and caspases and characterized inflammasome activation and regulation in detail. We here demonstrate that primary microglia can respond to the same innate stimuli as hematopoietic macrophages. However, microglial responses are more persistent due to lack of negative regulation on pro-IL-1β expression. In addition, we show that while caspase 1, 4, and 5 activation is pivotal for inflammasome-induced IL-1β secretion by hematopoietic macrophages, microglial secretion of IL-1β is only partially dependent on these inflammatory caspases. These results identify key cell type-specific differences that may aid the development of strategies to modulate innate immune responses in the brain.", "title": "Inflammasome-induced IL-1β secretion in microglia is characterized by delayed kinetics and is only partially dependent on inflammatory caspases." }, { "docid": "16058322", "text": "beta-Cell destruction in type 1 diabetes (T1D) is at least in part consequence of a 'dialog' between beta-cells and immune system. This dialog may be affected by the individual's genetic background. We presently evaluated whether modulation of MDA5 and PTPN2, two candidate genes for T1D, affects beta-cell responses to double-stranded RNA (dsRNA), a by-product of viral replication. These genes were selected following comparison between known candidate genes for T1D and genes expressed in pancreatic beta-cells, as identified in previous array analysis. INS-1E cells and primary fluorescence-activated cell sorting-purified rat beta-cells were transfected with small interference RNAs (siRNAs) targeting MDA5 or PTPN2 and subsequently exposed to intracellular synthetic dsRNA (polyinosinic-polycitidilic acid-PIC). Real-time RT-PCR, western blot and viability assays were performed to characterize gene/protein expression and viability. PIC increased MDA5 and PTPN2 mRNA expression, which was inhibited by the specific siRNAs. PIC triggered apoptosis in INS-1E and primary beta-cells and this was augmented by PTPN2 knockdown (KD), although inhibition of MDA5 did not modify PIC-induced apoptosis. In contrast, MDA5 silencing decreased PIC-induced cytokine and chemokine expression, although inhibition of PTPN2 induced minor or no changes in these inflammatory mediators. These findings indicate that changes in MDA5 and PTPN2 expression modify beta-cell responses to dsRNA. MDA5 regulates inflammatory signals, whereas PTPN2 may function as a defence mechanism against pro-apoptotic signals generated by dsRNA. These two candidate genes for T1D may thus modulate beta-cell apoptosis and/or local release of inflammatory mediators in the course of a viral infection by acting, at least in part, at the pancreatic beta-cell level.", "title": "MDA5 and PTPN2, two candidate genes for type 1 diabetes, modify pancreatic β-cell responses to the viral by-product double-stranded RNA" }, { "docid": "30908508", "text": "Objective: To investigate the regulation of CD4+CD25+ Regulatory T cells (Tregs) on pro-inflammatory adhesion molecules, Krüppel-Like Factor-2 (KLF-2) and its downstream transcriptional targets in human umbilical vein endothelial cells (HUVECs) impaired by ox-LDL and the mechanisms of it. Methods and results: HUVECs were cultured in the continuous presence of ox-LDL(0 mg/L,25 mg/L,50 mg/L,100 mg/L) for 4, 6, 12 and 24 hours to allow identification of early-and late-induced genes, respectively, whereas non-stimulated controls were taken at 0 hours. The expression of pro-inflammatory adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), E-selectin, KLF-2 and its target genes eNOS, PAI-1 were determined by real time RT-PCR and/or western-blot analysis. Expression of pro-inflammatory adhesion molecules, KLF-2, eNOS and PAI-1 in HUVEC cultured alone or with anti-CD3 mAbs activated Tregs, followed by addition of ox-LDL (50 mg/L) for 6 hours, are compared to expression levels in control cultures. Ox-LDL treated HUVECs increased pro-inflammatory adhesion molecules expression, as well as increased PAI-1 but decreased eNOS expression accompanied with significant downregulating of KLF-2 at a dose and time dependent manner. Furthermore, ox-LDL increased pro-inflammatory adhesion molecules but inhibited KLF2 expression was reversed by addition of Tregs. Small interfering RNA reduced endogenous KLF-2 expression and partly reversed the suppressive effect of Tregs on HUVECs activation, which strongly implicate KLF-2 as a transcriptional regulator of the Tregs-mediated effects in endothelial cells. Mechanism studies reveal that Treg-mediated KLF2 expression in HUVECs impaired by ox-LDL requires cell contact as well as soluble factors. Conclusions: Tregs could protect endothelial function that is largely dependent on KLF2 and its downstream transcriptional targets regulation involving cell-to-cell contact and soluble factors.", "title": "CD4+CD25+Foxp3+Regulatory T Cells Protect Endothelial Function Impaired by Oxidized Low Density Lipoprotein via the KLF-2 Transcription Factor" }, { "docid": "22889972", "text": "Inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha) have been implicated in atherogenesis. However, the precise role of TNF-alpha in atherogenesis is still unclear. To examine the effect of TNF-alpha on atherogenesis, we generated compound-deficient mice in apolipoprotein E (apoE) and TNF-alpha (apoE-/-/TNF-alpha-/-) and compared them with apoE-/- mice. Although serum total cholesterol levels were markedly elevated in both apoE-/-/TNF-alpha-/- and apoE-/- mice compared to wild-type mice, no differences were observed between apoE-/-/TNF-alpha-/- and apoE-/- mice. The atherosclerotic plaque area in the aortic luminal surface of apoE-/-/TNF-alpha-/- mice (n=8, 3.1+/-0.4%) was significantly smaller than that of apoE-/- mice (n=7, 4.7+/-0.4%, p<0.001) despite the lack of difference in serum cholesterol levels. The atherosclerotic lesion size in the aortic sinus of apoE-/-/TNF-alpha-/- mice (n=10, 5.1+/-0.3 x 10(5)microm(2)) was also significantly smaller than that of apoE-/- mice (n=11, 7.0+/-0.3 x 10(5)microm(2), p<0.0001). RT-PCR analysis indicated that the expression levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) were significantly higher in apoE-/- than apoE-/-/TNF-alpha-/- mice. Macrophages from apoE(-/-) mice showed higher uptake level of oxidized LDL and increased expression level of scavenger receptor class A (SRA) compared to those from apoE-/-/TNF-alpha-/- mice. These results indicate that TNF-alpha plays an atherogenic role by upregulating the expressions of ICAM-1, VCAM-1 and MCP-1 in the vascular wall, and by inducing SRA expression and oxidized LDL uptake in macrophages.", "title": "Disruption of tumor necrosis factor-alpha gene diminishes the development of atherosclerosis in ApoE-deficient mice." }, { "docid": "8702697", "text": "AIMS Tumor microenvironment is a strong determinant for the acquisition of metastatic potential of cancer cells. We have recently demonstrated that cancer-associated fibroblasts (CAFs) elicit a redox-dependent epithelial-mesenchymal transition (EMT) in prostate cancer (PCa) cells, driven by cycloxygenase-2/hypoxia-inducible factor-1 (HIF-1)/nuclear factor-κB pathway and enhancing tumor aggressiveness. Here, we investigated the involvement of microRNAs (miRNAs) in tumor-stroma interplay to identify possible tools to counteract oxidative stress and metastasis dissemination. \n RESULTS We found that miR-205 is the most downmodulated miRNA in PCa cells upon CAF stimulation, due to direct transcriptional repression by HIF-1, a known redox-sensitive transcription factor. Rescue experiments demonstrated that ectopic miR-205 overexpression in PCa cells counteracts CAF-induced EMT, thus impairing enhancement of cell invasion, acquisition of stem cell traits, tumorigenicity, and metastatic dissemination. In addition, miR-205 blocks tumor-driven activation of surrounding fibroblasts by reducing pro-inflammatory cytokine secretion. INNOVATION Overall, such findings suggest miR-205 as a brake against PCa metastasis by blocking both the afferent and efferent arms of the circuit between tumor cells and associated fibroblasts, thus interrupting the pro-oxidant and pro-inflammatory circuitries engaged by reactive stroma. \n CONCLUSION The evidence that miR-205 replacement in PCa cells is able not only to prevent but also to revert the oxidative/pro-inflammatory axis leading to EMT induced by CAFs sets the rationale for developing miRNA-based approaches to prevent and treat metastatic disease.", "title": "miR-205 hinders the malignant interplay between prostate cancer cells and associated fibroblasts." }, { "docid": "9588931", "text": "Vascular calcification is a strong independent predictor of increased cardiovascular morbidity and mortality and has a high prevalence among patients with chronic kidney disease. The present study investigated the effects of quercetin on vascular calcification caused by oxidative stress and abnormal mitochondrial dynamics both in vitro and in vivo. Calcifying vascular smooth muscle cells (VSMCs) treated with inorganic phosphate (Pi) exhibited mitochondrial dysfunction, as demonstrated by decreased mitochondrial potential and ATP production. Disruption of mitochondrial structural integrity was also observed in a rat model of adenine-induced aortic calcification. Increased production of reactive oxygen species, enhanced expression and phosphorylation of Drp1, and excessive mitochondrial fragmentation were also observed in Pi-treated VSMCs. These effects were accompanied by mitochondria-dependent apoptotic events, including release of cytochrome c from the mitochondria into the cytosol and subsequent activation of caspase-3. Quercetin was shown to block Pi-induced apoptosis and calcification of VSMCs by inhibiting oxidative stress and decreasing mitochondrial fission by inhibiting the expression and phosphorylation of Drp1. Quercetin also significantly ameliorated adenine-induced aortic calcification in rats. In summary, our findings suggest that quercetin attenuates calcification by reducing apoptosis of VSMCs by blocking oxidative stress and inhibiting mitochondrial fission.", "title": "Quercetin attenuates vascular calcification by inhibiting oxidative stress and mitochondrial fission." }, { "docid": "4418070", "text": "Regulatory T (Treg) cells, characterized by expression of the transcription factor forkhead box P3 (Foxp3), maintain immune homeostasis by suppressing self-destructive immune responses. Foxp3 operates as a late-acting differentiation factor controlling Treg cell homeostasis and function, whereas the early Treg-cell-lineage commitment is regulated by the Akt kinase and the forkhead box O (Foxo) family of transcription factors. However, whether Foxo proteins act beyond the Treg-cell-commitment stage to control Treg cell homeostasis and function remains largely unexplored. Here we show that Foxo1 is a pivotal regulator of Treg cell function. Treg cells express high amounts of Foxo1 and display reduced T-cell-receptor-induced Akt activation, Foxo1 phosphorylation and Foxo1 nuclear exclusion. Mice with Treg-cell-specific deletion of Foxo1 develop a fatal inflammatory disorder similar in severity to that seen in Foxp3-deficient mice, but without the loss of Treg cells. Genome-wide analysis of Foxo1 binding sites reveals ∼300 Foxo1-bound target genes, including the pro-inflammatory cytokine Ifng, that do not seem to be directly regulated by Foxp3. These findings show that the evolutionarily ancient Akt–Foxo1 signalling module controls a novel genetic program indispensable for Treg cell function.", "title": "Novel Foxo1-dependent transcriptional programs control Treg cell function" }, { "docid": "11557602", "text": "LXR alpha is a nuclear receptor that has previously been shown to regulate the metabolic conversion of cholesterol to bile acids. Here we define a role for this transcription factor in the control of cellular cholesterol efflux. We demonstrate that retroviral expression of LXR alpha in NIH 3T3 fibroblasts or RAW264.7 macrophages and/or treatment of these cells with oxysterol ligands of LXR results in 7- to 30-fold induction of the mRNA encoding the putative cholesterol/phospholipid transporter ATP-binding cassette (ABC)A1. In contrast, induction of ABCA1 mRNA in response to oxysterols is attenuated in cells that constitutively express dominant-negative forms of LXR alpha or LXR beta that lack the AF2 transcriptional activation domain. We further demonstrate that expression of LXR alpha in NIH 3T3 fibroblasts and/or treatment of these cells with oxysterols is sufficient to stimulate cholesterol efflux to extracellular apolipoprotein AI. The ability of oxysterol ligands of LXR to stimulate efflux is dramatically reduced in Tangier fibroblasts, which carry a loss of function mutation in the ABCA1 gene. Taken together, these results indicate that cellular cholesterol efflux is controlled, at least in part, at the level of transcription by a nuclear receptor-signaling pathway. They suggest a model in which activation of LXRs by oxysterols in response to cellular sterol loading leads to induction of the ABCA1 transporter and the stimulation of lipid efflux to extracellular acceptors. These findings have important implications for our understanding of mammalian cholesterol homeostasis and suggest new opportunities for pharmacological regulation of cellular lipid metabolism.", "title": "Control of cellular cholesterol efflux by the nuclear oxysterol receptor LXR alpha." }, { "docid": "41877386", "text": "CD4(+)CD25(+) regulatory T cells (T regs) play a major role in the maintenance of self-tolerance and immune suppression, although the mechanisms controlling T reg development and suppressor function remain incompletely understood. Herein, we provide evidence that Kruppel-like factor 10 (KLF10/TIEG1) constitutes an important regulator of T regulatory cell suppressor function and CD4(+)CD25(-) T cell activation through distinct mechanisms involving transforming growth factor (TGF)-beta1 and Foxp3. KLF10 overexpressing CD4(+)CD25(-) T cells induced both TGF-beta1 and Foxp3 expression, an effect associated with reduced T-Bet (Th1 marker) and Gata3 (Th2 marker) mRNA expression. Consistently, KLF10(-/-) CD4(+)CD25(-) T cells have enhanced differentiation along both Th1 and Th2 pathways and elaborate higher levels of Th1 and Th2 cytokines. Furthermore, KLF10(-/-) CD4(+)CD25(-) T cell effectors cannot be appropriately suppressed by wild-type T regs. Surprisingly, KLF10(-/-) T reg cells have reduced suppressor function, independent of Foxp3 expression, with decreased expression and elaboration of TGF-beta1, an effect completely rescued by exogenous treatment with TGF-beta1. Mechanistic studies demonstrate that in response to TGF-beta1, KLF10 can transactivate both TGF-beta1 and Foxp3 promoters, implicating KLF10 in a positive feedback loop that may promote cell-intrinsic control of T cell activation. Finally, KLF10(-/-) CD4(+)CD25(-) T cells promoted atherosclerosis by approximately 2-fold in ApoE(-/-)/scid/scid mice with increased leukocyte accumulation and peripheral pro-inflammatory cytokines. Thus, KLF10 is a critical regulator in the transcriptional network controlling TGF-beta1 in both CD4(+)CD25(-) T cells and T regs and plays an important role in regulating atherosclerotic lesion formation in mice.", "title": "Kruppel-like factor KLF10 targets transforming growth factor-beta1 to regulate CD4(+)CD25(-) T cells and T regulatory cells." } ]

[ { "docid": "8883846", "text": "The Global HIV Vaccine Enterprise convened a two-day workshop in May of 2007 to discuss humoral immune responses to HIV and approaches to design vaccines that induce viral neutralizing and other potentially protective antibody responses. The goals of this workshop were to identify key scientific issues, gaps, and opportunities that have emerged since the Enterprise Strategic Plan was first published in 2005 [1], and to make recommendations that Enterprise stakeholders can use to plan new activities. Most effective viral vaccines work, at least in part, by generating antibodies that inactivate or neutralize the invading virus, and the existing data strongly suggest that an optimally effective HIV-1 vaccine should elicit potent antiviral neutralizing antibodies. However, unlike acute viral pathogens, HIV-1 chronically replicates in the host and evades the antibody response. This immune evasion, along with the large genetic variation among HIV-1 strains worldwide, has posed major obstacles to vaccine development. Current HIV vaccine candidates do not elicit neutralizing antibodies against most circulating virus strains, and thus the induction of a protective antibody response remains a major priority for HIV-1 vaccine development. For an antibody-based HIV-1 vaccine, progress in vaccine design is generally gauged by in vitro assays that measure the ability of vaccine-induced antibodies to neutralize a broad spectrum of viral isolates representing the major genetic subtypes (clades) of HIV-1 [2]. Although it is not known what magnitude and breadth of neutralization will predict protection in vaccine recipients, it is clear that current vaccine immunogens elicit antibodies that neutralize only a minority of circulating isolates. Thus, much progress needs to be made in this area. Also, though virus neutralization is considered a critical benchmark for a vaccine, this may not be the only benchmark for predicting success with antibody-based HIV-1 vaccine immunogens. The main targets for neutralizing antibodies to HIV-1 are the surface gp120 and trans-membrane gp41 envelope glycoproteins (Env) that mediate receptor and coreceptor binding and the subsequent membrane fusion events that allow the virus to gain entry into cells [3]. Antibodies neutralize the virus by binding these viral spikes and blocking virus entry into susceptible cells, such as CD4+ T cells [4,5]. In order to chronically replicate in the host, the virus exploits several mechanisms to shield itself against antibody recognition, including a dense outer coating of sugar molecules (N-linked glycans) and the strategic positioning of cysteine–cysteine loop structures on the gp120 molecule [6–8]. These shielding mechanisms, although highly effective, have vulnerabilities imposed by fitness constraints. Information on the precise location and molecular structure of these vulnerable regions could be valuable for the rational design of improved vaccine immunogens. Participants in the workshop identified four areas that, if given proper attention, could provide key information that would bring the field closer to an effective antibody-based HIV-1 vaccine: (1) structure-assisted immunogen design, (2) role of Fc receptors and complement, (3) assay standardization and validation, and (4) immunoregulation of B cell responses.", "title": "Antibody-Based HIV-1 Vaccines: Recent Developments and Future Directions" } ]

[ { "docid": "20261352", "text": "OBJECTIVE To define the impact of chronic viremia and associated immune activation on B-cell exhaustion in HIV infection. \n DESIGN Progressive HIV infection is marked by B-cell anergy and exhaustion coupled with dramatic hypergammaglobulinemia. Although both upregulation of CD95 and loss of CD21 have been used as markers of infection-associated B-cell dysfunction, little is known regarding the specific profiles of dysfunctional B cells and whether persistent viral replication and its associated immune activation play a central role in driving B-cell dysfunction. \n METHODS Multiparameter flow cytometry was used to define the profile of dysfunctional B cells. The changes in the expression of CD21 and CD95 were tracked on B-cell subpopulations in patients with differential control of viral replication. \n RESULTS : Although the emergence of exhausted, CD21 tissue-like memory B cells followed similar patterns in both progressors and controllers, the frequency of CD21 activated memory B cells was lower in spontaneous controllers. \n CONCLUSION Our results suggest that the loss of CD21 and the upregulation of CD95 occur as separate events during the development of B-cell dysfunction. The loss of CD21 is a marker of B-cell exhaustion induced in the absence of appreciable viral replication, whereas the upregulation of CD95 is tightly linked to persistent viral replication and its associated immune activation. Thus, these dysfunctional profiles potentially represent two functionally distinct states within the B-cell compartment.", "title": "Decoupling activation and exhaustion of B cells in spontaneous controllers of HIV infection." }, { "docid": "14657344", "text": "Leishmania mexicana (Lm) causes localized (LCL) and diffuse (DCL) cutaneous leishmaniasis. DCL patients have a poor cellular immune response leading to chronicity. It has been proposed that CD8 T lymphocytes (CD8) play a crucial role in infection clearance, although the role of CD8 cytotoxicity in disease control has not been elucidated. Lesions of DCL patients have been shown to harbor low numbers of CD8, as compared to patients with LCL, and leishmanicidal treatment restores CD8 numbers. The marked response of CD8 towards Leishmania parasites led us to analyze possible functional differences between CD8 from patients with LCL and DCL. We compared IFNγ production, antigen-specific proliferation, and cytotoxicity of CD8 purified from PBMC against autologous macrophages (MO) infected with Leishmania mexicana (MOi). Additionally, we analyzed tissue biopsies from both groups of patients for evidence of cytotoxicity associated with apoptotic cells in the lesions. We found that CD8 cell of DCL patients exhibited low cytotoxicity, low antigen-specific proliferation and low IFNγ production when stimulated with MOi, as compared to LCL patients. Additionally, DCL patients had significantly less TUNEL+ cells in their lesions. These characteristics are similar to cellular \"exhaustion\" described in chronic infections. We intended to restore the functional capacity of CD8 cells of DCL patients by preincubating them with TLR2 agonists: Lm lipophosphoglycan (LPG) or Pam3Cys. Cytotoxicity against MOi, antigen-specific proliferation and IFNγ production were restored with both stimuli, whereas PD-1 (a molecule associated with cellular exhaustion) expression, was reduced. Our work suggests that CD8 response is associated with control of Lm infection in LCL patients and that chronic infection in DCL patients leads to a state of CD8 functional exhaustion, which could facilitate disease spread. This is the first report that shows the presence of functionally exhausted CD8 T lymphocytes in DCL patients and, additionally, that pre-stimulation with TLR2 ligands can restore the effector mechanisms of CD8 T lymphocytes from DCL patients against Leishmania mexicana-infected macrophages.", "title": "CD8 Cells of Patients with Diffuse Cutaneous Leishmaniasis Display Functional Exhaustion: The Latter Is Reversed, In Vitro, by TLR2 Agonists" }, { "docid": "15521377", "text": "Cellular senescence is a stable form of cell-cycle arrest which is thought to limit the proliferative potential of premalignant cells [1]. The senescence phenotype was initially described by Hayflick and Moorhead in 1961 on human fibroblasts undergoing replicative exhaustion in culture [2]. It has been shown that senescence can be triggered in different cell types in response to diverse forms of cellular damage or stress (for review see [1]). Importantly, while senescence was denounced as a tissue culture phenomenon for many years, recent in vivo studies demonstrated that cellular senescence represents a potent failsafe mechanism against tumorigenesis and contributes to the cytotoxicity of certain anticancer agents (see for example [3-7]). Interestingly, senescent cells have also been observed in certain aged or damaged tissues and there is growing evidence that senescence checkpoints can affect the regenerative reserve of tissues and organismal aging [8-11]. However, senescence may also have positive effects on organ maintenance by limiting pathological responses to acute forms of injury such as fibrotic scarring in response to chemical induced liver injury [12]. Over the past years it was also shown that senescent cells can communicate with their environment by secreting a myriad of cytokines and growth factors. Interestingly, this \"senescence associated secretory phenotype (SASP)\" seems to be a double edged sword regarding tumor initiation and maintenance: i) On the one hand, it has been shown that the SASP can have pro-tumorigenic effects. In an experimental system it was shown that senescent mesenchymal cells can enhance the tumorigenicity of surrounding breast cancer cells [13]. ii) Similarly, it is possible that the SASP enhances selection of transformed cell clones in aged organ systems. It has been shown that loss of proliferative competition of non-transformed cells can accelerate leukemogenesis [14]. It remains to be seen whether aberrant secretion of cytokines and growth factors by the SASP can accelerated this process in aged and chronically damage organ systems. iii) In contrast to its pro-tumorigenic aspect, the SASP could also have anti-tumor effects. A recent study showed that in a mosaic liver cancer mouse model the activation of p53 induced senescence, an upregulation of inflammatory cytokines, and activation of innate immune responses leading to tumour cell clearance [15]. iv) In further support that the SASP could have anti-tumor activities, a series of recent papers showed that components of the SASP can stabilize the senescence cell cycle arrest via an autoregulatory feedback loop [16,17] or induces apoptosis of tumor cells [18]. In addition to its effects on tumorigenesis, the SASP could also influence tissue aging. Studies on aging telomere dysfunctional mice have provided direct experimental evidence for an in vivo activation of the SASP in response to telomere dysfunction [19]. Interestingly, this in vivo SASP provoked alterations in stem cell differentiation (skewing of hematopoiesis towards reduction in lymphopoiesis and enhancement of myelopoiesis) that are also characteristic signs of human aging. Figure 1. Different cellular stresses can induce senescence including telomere shortening, DNA damage, and oncogene activation. Senescence of tumor cells ... In light of the many possible roles o the SASP in aging and carcinogenesis, it appears to be of utmost importance to decipher regulatory pathways controlling the SASP. In a current publication, Bhaumik et al. have identified 2 microRNAs (miR-146a/b) that negatively regulate the secretion of IL-6 and IL-8 - two of the SASP [20]. The authors show that these microRNAs are up-regulated at late stages of senescence, many days after a permanent cell cycle arrest has been established. Interestingly, the inhibitory miRs are most strongly up-regulated in senescence of cell lines that show a strong SASP but not in cell lines characterized by a weak SASP. The authors propose a new concept indicating that miRs 146a and b function in a negative feedback loop preventing an over-activation of the SASP in senescent cells. The authors present some initial data suggesting that activation of this negative feedback loop involves IL-1 receptor, IRAK-1, and NFκB signalling leading to an up-regulation of miRs-146a and b. A direct proof that this proposed feedback loop suppresses over-activation of the SASP remains to be demonstrated in future studies. The authors show that blockage of IL-1-receptor signalling prevents both the up-regulation of miRs-146a and b as well as Il-6 secretion. To confirm their new concept, it would be important to show that a selective blockage of miRs-146a and b results in over-activation of the SASP. The work by Bhaumik et al. places mir-146a/b as central players to control IL-6 and IL-8 expression within the SASP. MicroRNAs are emerging therapeutic targets because their expression levels can be effectively modulated via the use of antagomirs (see for example [21]). Also, for increasing microRNA expression, microRNAs can be delivered into cellsin vivo (see for example [22]). Therefore, it will be interesting to functionally test the impact of mir-146 inhibition on tumorigenesis and aging in relevant mouse models. Such studies will be of particular interest, as recent work showed that IL-6 secretion by senescent cells is relevant for initiating and maintaining the senescene response via an autocrine loop [17]. A reduction of miR-146 could increase IL-6 levels in senescent cells, which should stabilize the senescence program and reduce the risk of malignant transformation. Furthermore, it can be speculated that reduction of mir-146 a/b will increase NfκB activation via IRAK1. As NfκB is modulating the expression of various inflammation associated genes, this may also lead to increased clearance of senescent tumor cells by the innate immune system. However, it should be mentioned that Il-6 secreted by senescent cells can also act as a mitogen for surrounding cells, thus potentially increasing the risk of malignant transformation [13,17]. Besides its function in SASP modulation, miR-146 was also reported to target the mRNAs of the BRCA1 and BRCA2 tumor suppressors. In a recent study a G to C polymorphism in miR-146, which leads to an increased processing and release of the mature microRNA, can predict an early onset of breast cancer [23]. Taken together, the study of Bhaumik et al. opens an interesting new research area dealing with the gene regulatory mechanisms that control activation of the SASP. Given the diverse roles of the SASP in modulating tumor progression, immune surveillance of damaged cells, and the stabilization of the senescence arrest itself, it will be of great interest to analyse the influence of SASP regulatory pathways during aging and cancer.", "title": "Keeping your senescent cells under control" }, { "docid": "14806256", "text": "CONTEXT Use of antiretroviral drugs, including protease inhibitors, for treatment of human immunodeficiency virus (HIV) infection has been anecdotally associated with hepatotoxicity, particularly in persons coinfected with hepatitis C or B virus. \n OBJECTIVES To ascertain if incidence of severe hepatotoxicity during antiretroviral therapy is similar for all antiretroviral drug combinations, and to define the role of chronic viral hepatitis in its development. \n DESIGN Prospective cohort study. \n SETTING University-based urban HIV clinic. \n PATIENTS A total of 298 patients who were prescribed new antiretroviral therapies between January 1996 and January 1998, 211 (71%) of whom received protease inhibitors as part of combination therapy (median follow-up, 182 days) and 87 (29%) of whom received dual nucleoside analog regimens (median follow-up, 167 days). Chronic hepatitis C and B virus infection was present in 154 (52%) and 8 (2.7%) patients, respectively. \n MAIN OUTCOME MEASURE Severe hepatotoxicity, defined as a grade 3 or 4 change in levels of serum alanine aminotransferase and aspartate aminotransferase, evaluated before and during therapy. \n RESULTS Severe hepatotoxicity was observed in 31 (10.4%) of 298 patients (95% confidence interval [CI], 7.2%-14.4%). Ritonavir use was associated with a higher incidence of toxicity (30%; 95% CI, 17.9% -44.6%). However, no significant difference was detected in hepatotoxicity incidence in other treatment groups, ie, nucleoside analogs (5.7%; 95% CI, 1.2%-12.9%), nelfinavir (5.9%; 95% CI, 1.2%-16.2%), saquinavir (5.9%; 95% CI, 0.15%-28.7%), and indinavir(6.8%; 95% CI, 3.0%-13.1 %). Although chronicviral hepatitis was associated with an increased risk of severe hepatotoxicity among patients prescribed nonritonavir regimens (relative risk, 3.7; 95% CI, 1.0-11.8), most patients with chronic hepatitis C or B virus infection (88%) did not experience significant toxic effects. Rate of severe toxicity with use of any protease inhibitor in patients with hepatitis C infection was 12.2% (13/107; 95% CI, 6.6%-19.9%). In multivariate logistic regression, only ritonavir (adjusted odds ratio [AOR], 8.6; 95% CI, 3.0-24.6) and a CD4 cell count increase of more than 0.05 x 10(9)/L (AOR, 3.6; 95% CI, 1.0-12.9) were associated with severe hepatotoxicity. No irreversible outcomes were seen in patients with severe hepatotoxicity. \n CONCLUSIONS Our data indicate that use of ritonavir may increase risk of severe hepatotoxicity. Although hepatotoxicity may be more common in persons with chronic viral hepatitis, these data do not support withholding protease inhibitor therapy from persons coinfected with hepatitis B or C virus.", "title": "Hepatotoxicity associated with antiretroviral therapy in adults infected with human immunodeficiency virus and the role of hepatitis C or B virus infection." }, { "docid": "40349336", "text": "Developmental abnormalities, cancer, and premature aging each have been linked to defects in the DNA damage response (DDR). Mutations in the ATR checkpoint regulator cause developmental defects in mice (pregastrulation lethality) and humans (Seckel syndrome). Here we show that eliminating ATR in adult mice leads to defects in tissue homeostasis and the rapid appearance of age-related phenotypes, such as hair graying, alopecia, kyphosis, osteoporosis, thymic involution, fibrosis, and other abnormalities. Histological and genetic analyses indicate that ATR deletion causes acute cellular loss in tissues in which continuous cell proliferation is required for maintenance. Importantly, thymic involution, alopecia, and hair graying in ATR knockout mice were associated with dramatic reductions in tissue-specific stem and progenitor cells and exhaustion of tissue renewal and homeostatic capacity. In aggregate, these studies suggest that reduced regenerative capacity in adults via deletion of a developmentally essential DDR gene is sufficient to cause the premature appearance of age-related phenotypes.", "title": "Deletion of the developmentally essential gene ATR in adult mice leads to age-related phenotypes and stem cell loss." }, { "docid": "5398179", "text": "HIV-1 replication is concentrated within CD4(+) T cells in B cell follicles of secondary lymphoid tissues during asymptomatic disease. Limited data suggest that a subset of T follicular helper cells (TFH) within germinal centers (GC) is highly permissive to HIV-1. Whether GC TFH are the major HIV-1 virus-producing cells in vivo has not been established. In this study, we investigated TFH permissivity to HIV-1 ex vivo by spinoculating and culturing tonsil cells with HIV-1 GFP reporter viruses. Using flow cytometry, higher percentages of GC TFH (CXCR5(high)PD-1(high)) and CXCR5(+)programmed cell death-1 (PD-1)(low) cells were GFP(+) than non-GC TFH (CXCR5(+)PD-1(intermediate)) or extrafollicular (EF) (CXCR5(-)) cells. When sorted prior to spinoculation, however, GC TFH were substantially more permissive than CXCR5(+)PD-1(low) or EF cells, suggesting that many GC TFH transition to a CXCR5(+)PD-1(low) phenotype during productive infection. In situ hybridization on inguinal lymph node sections from untreated HIV-1-infected individuals without AIDS revealed higher frequencies of HIV-1 RNA(+) cells in GC than non-GC regions of follicle or EF regions. Superinfection of HIV-1-infected individuals' lymph node cells with GFP reporter virus confirmed the permissivity of follicular cells ex vivo. Lymph node immunostaining revealed 96% of CXCR5(+)CD4(+) cells were located in follicles. Within sorted lymph node cells from four HIV-infected individuals, CXCR5(+) subsets harbored 11-66-fold more HIV-1 RNA than CXCR5(-) subsets, as determined by RT PCR. Thus, GC TFH are highly permissive to HIV-1, but downregulate PD-1 and, to a lesser extent, CXCR5 during HIV-1 replication. These data further implicate GC TFH as the major HIV-1-producing cells in chronic asymptomatic HIV-1 infection.", "title": "Germinal Center T Follicular Helper Cells Are Highly Permissive to HIV-1 and Alter Their Phenotype during Virus Replication." }, { "docid": "23848916", "text": "This study found that oridonin, a natural diterpenoid purified from Rabdosia rubescens, inhibited growth of multiple myeloma (MM; U266, RPMI8226), acute lymphoblastic T-cell leukemia (Jurkat), and adult T-cell leukemia (MT-1) cells with an effective dose that inhibited 50% of target cells (ED50) ranging from 0.75 to 2.7 microg/mL. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling staining showed that oridonin caused apoptosis of MT-1 cells in a time-dependent manner. We explored effects of oridonin on antiapoptotic Bcl-2 family members and found that it down-regulated levels of Mcl-1 and BCL-x(L), but not Bcl-2 protein, in both MT-1 and RPMI8226 cells. Further studies found that oridonin inhibited nuclear factor-kappa B (NF-kappa B) DNA-binding activity in these cells as measured by luciferase reporter gene, ELISA-based, and electrophoretic mobility shift assays. Oridonin also blocked tumor necrosis factor-alpha- and lipopolysaccharide-stimulated NF-kappa B activity in Jurkat cells as well as RAW264.7 murine macrophages. Of note, oridonin decreased survival of freshly isolated adult T-cell leukemia (three samples), acute lymphoblastic leukemia (one sample), chronic lymphocytic leukemia (one sample), non-Hodgkin's lymphoma (three samples), and MM (four samples) cells from patients in association with inhibition of NF-kappa B DNA-binding activity. On the other hand, oridonin did not affect survival of normal lymphoid cells from healthy volunteers. Taken together, oridonin might be useful as adjunctive therapy for individuals with lymphoid malignancies, including the lethal disease adult T-cell leukemia.", "title": "Oridonin, a diterpenoid purified from Rabdosia rubescens, inhibits the proliferation of cells from lymphoid malignancies in association with blockade of the NF-kappa B signal pathways." }, { "docid": "3090454", "text": "In 93 allograft recipients, the numbers of marrow B-cell precursors on days 80 and 365 correlated with the counts of circulating B cells, suggesting that the posttransplantation B-cell deficiency is at least in part due to insufficient B lymphopoiesis. Factors that could affect B lymphopoiesis were evaluated. The number of marrow B-cell precursors on days 30 and 80 was at least 4-fold lower in patients with grade 2 to 4 acute graft-versus-host disease (GVHD) compared with patients with grade 0 to 1 acute GVHD. The number of B-cell precursors on day 365 was 18-fold lower in patients with extensive chronic GVHD compared with patients with no or limited chronic GVHD. The number of B-cell precursors was not related to CD34 cell dose, type of transplant (marrow versus blood stem cells), donor age, or patient age. It was concluded that posttransplantation B-cell deficiency results in part from inhibition of B lymphopoiesis by GVHD and/or its treatment.", "title": "Factors influencing B lymphopoiesis after allogeneic hematopoietic cell transplantation." }, { "docid": "28644298", "text": "Epstein-Barr virus (EBV) latency III infection converts B lymphocytes into lymphoblastoid cell lines (LCLs) by expressing EBV nuclear and membrane proteins, EBNAs, and latent membrane proteins (LMPs), which regulate transcription through Notch and tumor necrosis factor receptor pathways. The role of NF-kappa B in LMP1 and overall EBV latency III transcriptional effects was investigated by treating LCLs with BAY11-7082 (BAY11). BAY11 rapidly and irreversibly inhibited NF-kappa B, decreased mitochondrial membrane potential, induced apoptosis, and altered LCL gene expression. BAY11 effects were similar to those of an NF-kappa B inhibitor, Delta N-I kappa B alpha, in effecting decreased JNK1 expression and in microarray analyses. More than 80% of array elements that decreased with Delta N-I kappa B alpha expression decreased with BAY11 treatment. Newly identified NF-kappa B-induced, LMP1-induced, and EBV-induced genes included pleckstrin, Jun-B, c-FLIP, CIP4, and I kappa B epsilon. Of 776 significantly changed array elements, 134 were fourfold upregulated in EBV latency III, and 74 were fourfold upregulated with LMP1 expression alone, whereas only 28 were more than fourfold downregulated by EBV latency III. EBV latency III-regulated gene products mediate cell migration (EBI2, CCR7, RGS1, RANTES, MIP1 alpha, MIP1 beta, CXCR5, and RGS13), antigen presentation (major histocompatibility complex proteins and JAW1), mitogen-activated protein kinase pathway (DUSP5 and p62Dok), and interferon (IFN) signaling (IFN-gamma R alpha, IRF-4, and STAT1). Comparison of EBV latency III LCL gene expression to immunoglobulin M (IgM)-stimulated B cells, germinal-center B cells, and germinal-center-derived lymphomas clustered LCLs with IgM-stimulated B cells separately from germinal-center cells or germinal-center lymphoma cells. Expression of IRF-2, AIM1, ASK1, SNF2L2, and components of IFN signaling pathways further distinguished EBV latency III-infected B cells from IgM-stimulated or germinal-center B cells.", "title": "Role of NF-kappa B in cell survival and transcription of latent membrane protein 1-expressing or Epstein-Barr virus latency III-infected cells." }, { "docid": "24596228", "text": "BACKGROUND/AIMS There is only limited information on the prevalence and influence of coinfection with either hepatitis B or C on the clinical course in patients infected with the human immunodeficiency virus (HIV). \n METHODS Follow-up was available in 232 HIV-infected patients (age 37+/-8 years, CD4 count 167+/-167 microl; 46% had AIDS). Samples were investigated for markers of HBV and HCV infection (HBsAg, HBeAg, HBV-DNA, Anti-HBs, anti-HBc, anti-HCV, HCV-RNA). \n RESULTS 60/232 patients (23%) were anti-HCV positive. 78% of these sera were positive for HCV-RNA. 22/232 patients (9%) suffered from chronic HBV infection (HBsAg positive), 18/22 (82%) of these sera had detectable HBeAg and 19/22 (86%) HBV-DNA. Presence of HCV-RNA, HBeAg and amount of HBV-DNA were related to the degree of immunodeficiency. In contrast to the control group without HBV or HCV infection, patients infected with HIV and either HBV or HCV showed a direct correlation between a reduction in CD4 counts and decreased cholinesterase activity. In patients with AIDS, coinfection with HBV or HCV was associated with a reduced survival compared to controls (HBV: 212 days, 95%CI, 106-317; HCV: 267, 95%CI, 112-396; controls: 439 days, 95%CI, 364-513). \n CONCLUSIONS Coinfection of HIV and HBV or HCV is frequently observed. Our results suggest that with prolonged survival of HIV-infected patients, coinfection with either HBV or HCV correlates with a reduced survival rate.", "title": "Hepatitis B and C in HIV-infected patients. Prevalence and prognostic value." }, { "docid": "35987381", "text": "Hyperactivation of T cells, particularly of CD8(+) T cells, is a hallmark of chronic HIV 1 (HIV-1) infection. Little is known about the antigenic specificities and the mechanisms by which HIV-1 causes activation of CD8(+) T cells during chronic infection. We report that CD8(+) T cells were activated during in vivo HIV-1 replication irrespective of their Ag specificity. Cytokines present during untreated HIV-1 infection, most prominently IL-15, triggered proliferation and expression of activation markers in CD8(+) T cells, but not CD4(+) T cells, in the absence of TCR stimulation. Moreover, LPS or HIV-1-activated dendritic cells (DCs) stimulated CD8(+) T cells in an IL-15-dependent but Ag-independent manner, and IL-15 expression was highly increased in DCs isolated from viremic HIV-1 patients, suggesting that CD8(+) T cells are activated by inflammatory cytokines in untreated HIV-1 patients independent of Ag specificity. This finding contrasts with CD4(+) T cells whose in vivo activation seems biased toward specificities for persistent Ags. These observations explain the higher abundance of activated CD8(+) T cells compared with CD4(+) T cells in untreated HIV-1 infection.", "title": "CD8+ T cells are activated in an antigen-independent manner in HIV-infected individuals." }, { "docid": "301866", "text": "Immune reconstitution was analyzed in 140 consecutive patients who were 2-year disease-free and who underwent myeloablative allogeneic transplantation. A CD4 and CD8 defect was observed involving naive, terminally differentiated, memory and competent cells and above limits values for activated subsets. Natural killer cells normalize at six months while we observed expansion of CD19(+)/CD5(+) B cells after three months and a persisting defect of memory B cells. Chronic graft-versus-host disease did not influence significantly those parameters for CD8 subsets while the naïve and competent CD4 subsets were strongly affected. But the most profound impact of chronic graft-versus-host disease was on B-cell subsets, especially on the memory B population. The cumulative incidence of late severe infections was low (14% at four years). Using Cox's models, only low B-cell counts at 12 (P=0.02) and 24 (P=0.001) months were associated with the hazard of developing late infection, in particular if patients did not develop chronic graft-versus-host disease.", "title": "Long-term immune deficiency after allogeneic stem cell transplantation: B-cell deficiency is associated with late infections." }, { "docid": "4387484", "text": "The Kaposi's sarcoma-associated herpesvirus (KSHV/HHV8) is a gamma-2 herpesvirus that is implicated in the pathogenesis of Kaposi's sarcoma and of primary effusion B-cell lymphomas (PELs). KSHV infects malignant and progenitor cells of Kaposi's sarcoma and PEL, it encodes putative oncogenes and genes that may cause Kaposi's sarcoma pathogenesis by stimulating angiogenesis. The G-protein-coupled receptor encoded by an open reading frame (ORF 74) of KSHV is expressed in Kaposi's sarcoma lesions and in PEL and stimulates signalling pathways linked to cell proliferation in a constitutive (agonist-independent) way. Here we show that signalling by this KSHV G-protein-coupled receptor leads to cell transformation and tumorigenicity, and induces a switch to an angiogenic phenotype mediated by vascular endothelial growth factor, an angiogenesis and Kaposi's-spindle-cell growth factor. We find that this receptor can activate two protein kinases, JNK/SAPK and p38MAPK, by triggering signalling cascades like those induced by inflammatory cytokines that are angiogenesis activators and mitogens for Kaposi's sarcoma cells and B cells. We conclude that the KSHV G-protein-coupled receptor is a viral oncogene that can exploit cell signalling pathways to induce transformation and angiogenesis in KSHV-mediated oncogenesis.", "title": "G-protein-coupled receptor of Kaposi's sarcoma-associated herpesvirus is a viral oncogene and angiogenesis activator." }, { "docid": "44562058", "text": "Despite complete or near-complete suppression of human immunodeficiency virus (HIV) replication with combination antiretroviral therapy, both HIV and chronic inflammation/immune dysfunction persist indefinitely. Untangling the association between the virus and the host immune environment during therapy might lead to novel interventions aimed at either curing the infection or preventing the development of inflammation-associated end-organ disease. Chronic inflammation and immune dysfunction might lead to HIV persistence by causing virus production, generating new target cells, enabling infecting of activated and resting target cells, altering the migration patterns of susceptible target cells, increasing the proliferation of infected cells, and preventing normal HIV-specific clearance mechanisms from function. Chronic HIV production or replication might contribute to persistent inflammation and immune dysfunction. The rapidly evolving data on these issues strongly suggest that a vicious cycle might exist in which HIV persistence causes inflammation that in turn contributes to HIV persistence.", "title": "Immune activation and HIV persistence: implications for curative approaches to HIV infection." }, { "docid": "23304931", "text": "PURPOSE Diffuse large B-cell lymphoma (DLBCL) represents a clinically heterogeneous disease. Models based on immunohistochemistry predict clinical outcome. These include subdivision into germinal center (GC) versus non-GC subtypes; proliferation index (measured by expression of Ki-67), and expression of BCL-2, FOXP1, or B-lymphocyte-induced maturation protein (Blimp-1)/PRDM1. We sought to determine whether immunohistochemical analyses of biopsies from patients with DLBCL having HIV infection are similarly relevant for prognosis. \n PATIENTS AND METHODS We examined 81 DLBCLs from patients with AIDS in AMC010 (cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP] v CHOP-rituximab) and AMC034 (etoposide, doxorubicin, vincristine, prednisone, and dose-adjusted cyclophosphamide plus rituximab concurrent v sequential) clinical trials and compared the immunophenotype with survival data, Epstein-Barr virus (EBV) positivity, and CD4 counts. \n RESULTS The GC and non-GC subtypes of DLBCL did not differ significantly with respect to overall survival or CD4 count at cancer presentation. EBV could be found in both subtypes of DLBCL, although less frequently in the GC subtype, and did not affect survival. Expression of FOXP1, Blimp-1/PRDM1, or BCL-2 was not correlated with the outcome in patients with AIDS-related DLBCL. \n CONCLUSION These data indicate that with current treatment strategies for lymphoma and control of HIV infection, commonly used immunohistochemical markers may not be clinically relevant in HIV-infected patients with DLBCL. The only predictive immunohistochemical marker was found to be Ki-67, where a higher proliferation index was associated with better survival, suggesting a better response to therapy in patients whose tumors had higher proliferation rates.", "title": "Immunophenotypic analysis of AIDS-related diffuse large B-cell lymphoma and clinical implications in patients from AIDS malignancies consortium clinical trials 010 and 034" }, { "docid": "14644164", "text": "TLR sense microbial infections, and control activation of immune responses. Dendritic cells, macrophages, and B lymphocytes express TLR and the TLR-signaling adaptor protein MyD88. The impact of TLR-activated B cells on T cell-mediated inflammation is unknown. In this study, we have used mice carrying B cell-restricted deficiencies in MyD88 or in distinct TLR to examine the impact of TLR-activated B cells on a T cell-mediated autoimmune disease, experimental autoimmune encephalomyelitis (EAE). We demonstrate that TLR-signaling in B cells suppresses inflammatory T cell responses (both Th1 and Th17), and stimulates recovery from EAE. Only certain TLR are required on B cells for resolution of EAE, and these are dispensable for disease initiation, indicating that a category of TLR agonists preferentially triggers a suppressive function in B cells and thereby limits autoimmune disease. The TLR agonists controlling the regulatory function of B cells are provided by components of Mycobacterium tuberculosis present in the adjuvant. Thus, MyD88 signaling in B cells antagonizes MyD88 signaling in other cells, which drives differentiation of Th17 cells and is required for induction of EAE. Altogether, our data indicate that B cells link recognition of microbial products via TLR to suppression of a T cell-mediated autoimmune disease.", "title": "TLR-activated B cells suppress T cell-mediated autoimmunity." }, { "docid": "30861948", "text": "The ubiquitously expressed nonreceptor tyrosine kinase c-Abl contains three nuclear localization signals, however, it is found in both the nucleus and the cytoplasm of proliferating fibroblasts. A rapid and transient loss of c-Abl from the nucleus is observed upon the initial adhesion of fibroblasts onto a fibronectin matrix, suggesting the possibility of nuclear export [Lewis, J., Baskaran, R. , Taagepera, S., Schwartz, M. & Wang, J. (1996) Proc. Natl. Acad. Sci. USA 93, 15174-15179]. Here we show that the C terminus of c-Abl does indeed contain a functional nuclear export signal (NES) with the characteristic leucine-rich motif. The c-Abl NES can functionally complement an NES-defective HIV Rev protein (RevDelta3NI) and can mediate the nuclear export of glutathione-S-transferase. The c-Abl NES function is sensitive to the nuclear export inhibitor leptomycin B. Mutation of a single leucine (L1064A) in the c-Abl NES abrogates export function. The NES-mutated c-Abl, termed c-Abl NES(-), is localized exclusively to the nucleus. Treatment of cells with leptomycin B also leads to the nuclear accumulation of wild-type c-Abl protein. The c-Abl NES(-) is not lost from the nucleus when detached fibroblasts are replated onto fibronectin matrix. Taken together, these results demonstrate that c-Abl shuttles continuously between the nucleus and the cytoplasm and that the rate of nuclear import and export can be modulated by the adherence status of fibroblastic cells.", "title": "Nuclear-cytoplasmic shuttling of C-ABL tyrosine kinase." }, { "docid": "23599024", "text": "Background/Aims: Radiotherapy is applied to patients with inoperable cancer types including advanced stage non-small cell lung cancer (NSCLC) and radioresistance functions as a critical obstacle in radiotherapy. This study was aimed to investigate the mechanism of radioresistance regulated by surfactant protein B (SP-B). Methods: To investigate the role of SP-B in radioresistance, ΔSFTPB A549 cell line was established and SP-B expression was analyzed. In response to ionizing radiation (IR), the change of SP-B expression was analyzed in A549 and NCI-H441 cell lines. Conditioned media (CM) from NSCLC cells were utilized to evaluate the downstream signaling pathway. The in vivo effects of SP-B were assessed through mouse xenograft model with intratumoral injection of CM. Results: In response to IR, NSCLC cell lines showed decreased SP-B regulated by the TGF-β signaling and decreased SP-B stimulated cell survival and epithelial-mesenchymal transition. Treatment with CM from irradiated cells activated sPLA2, enhanced protein kinase Cδ-MAPKs signaling pathway, and increased arachidonic acid production. We confirmed the in vivo roles of SP-B through mouse xenograft model. Conclusion: Our results revealed that down-regulation of SP-B was involved in the radiation-induced metastatic conversion of NSCLC and provided evidence that SP-B acted as a suppressor of NSCLC progression.", "title": "Surfactant Protein B Suppresses Lung Cancer Progression by Inhibiting Secretory Phospholipase A2 Activity and Arachidonic Acid Production" }, { "docid": "4653837", "text": "The mechanisms underlying the development of aging-induced muscle atrophy are unclear. By microRNA array and individual qPCR analyses, we found significant up-regulation of miR-29 in muscles of aged rodents vs. results in young. With aging, p85α, IGF-1 and B-myb muscle levels were lower while the expression of certain cell arrest proteins (p53, p16 and pRB) increased. When miR-29 was expressed in muscle progenitor cells (MPC), their proliferation was impaired while SA-βgal expression increased signifying the development of senescence. Impaired MPC proliferation resulted from interactions between miR-29 and the 3'-UTR of p85a, IGF-1 and B-myb, suppressing the translation of these mediators of myoblast proliferation. In vivo, electroporation of miR-29 into muscles of young mice suppressed the proliferation and increased levels of cellular arrest proteins, recapitulating aging-induced responses in muscle. A potential stimulus of miR-29 expression is Wnt-3a since we found that exogenous Wnt-3a stimulated miR-29 expression 2.7-fold in primary cultures of MPCs. Thus, aging-induced muscle senescence results from activation of miR-29 by Wnt-3a leading to suppressed expression of several signaling proteins (p85α, IGF-1 and B-myb) that act coordinately to impair the proliferation of MPCs contributing to muscle atrophy. The increase in miR-29 provides a potential mechanism for aging-induced sarcopenia.", "title": "MicroRNA-29 induces cellular senescence in aging muscle through multiple signaling pathways" } ]

[ { "docid": "14610165", "text": "Antisense transcription is widespread in many genomes; however, how much is functional is hotly debated. We are investigating functionality of a set of long noncoding antisense transcripts, collectively called COOLAIR, produced at Arabidopsis FLOWERING LOCUS C (FLC). COOLAIR initiates just downstream of the major sense transcript poly(A) site and terminates either early or extends into the FLC promoter region. We now show that splicing of COOLAIR is functionally important. This was revealed through analysis of a hypomorphic mutation in the core spliceosome component PRP8. The prp8 mutation perturbs a cotranscriptional feedback mechanism linking COOLAIR processing to FLC gene body histone demethylation and reduced FLC transcription. The importance of COOLAIR splicing in this repression mechanism was confirmed by disrupting COOLAIR production and mutating the COOLAIR proximal splice acceptor site. Our findings suggest that altered splicing of a long noncoding transcript can quantitatively modulate gene expression through cotranscriptional coupling mechanisms.", "title": "Functional Consequences of Splicing of the Antisense Transcript COOLAIR on FLC Transcription" } ]

[ { "docid": "14050257", "text": "Long non-protein-coding RNAs (lncRNAs) are proposed to be the largest transcript class in the mouse and human transcriptomes. Two important questions are whether all lncRNAs are functional and how they could exert a function. Several lncRNAs have been shown to function through their product, but this is not the only possible mode of action. In this review we focus on a role for the process of lncRNA transcription, independent of the lncRNA product, in regulating protein-coding-gene activity in cis. We discuss examples where lncRNA transcription leads to gene silencing or activation, and describe strategies to determine if the lncRNA product or its transcription causes the regulatory effect.", "title": "Gene regulation by the act of long non-coding RNA transcription" }, { "docid": "18924534", "text": "The mammalian genome harbors thousands of long noncoding RNA (lncRNA) genes. Recent studies have indicated the involvement of several of these lncRNAs in the regulation of gene expression. lncRNAs play crucial roles in various biological processes ranging from epigenetic gene regulation, transcriptional control, to post-transcriptional regulation. lncRNAs are localized in various subcellular compartments, and major proportion of these are retained in the cell nucleus and could be broadly classified as nuclear-retained lncRNAs (nrRNAs). Based on the identified functions, members of the nrRNAs execute diverse roles, including providing architectural support to the hierarchical subnuclear organization and influencing the recruitment of chromatin modifier factors to specific chromatin sites. In this review, we will summarize the recently described roles of mammalian nrRNAs in controlling gene expression by influencing chromatin organization, transcription, pre-mRNA processing, nuclear organization, and their involvement in disease.", "title": "Functional insights into the role of nuclear-retained long noncoding RNAs in gene expression control in mammalian cells" }, { "docid": "9655347", "text": "BACKGROUND Long non-coding RNAs (lncRNAs) are a sub-class within non-coding RNA repertoire that have emerged as crucial regulators of the gene expression in various pathophysiological conditions. lncRNAs display remarkable versatility and wield their functions through interactions with RNA, DNA, or proteins. Accumulating body of evidence based on multitude studies has highlighted the role of lncRNAs in many autoimmune and inflammatory diseases, including type 1 diabetes (T1D). This review highlights emerging roles of lncRNAs in immune and islet β cell function as well as some of the challenges and opportunities in understanding the pathogenesis of T1D and its complications. \n CONCLUSION We accentuate that the lncRNAs within T1D-loci regions in consort with regulatory variants and enhancer clusters orchestrate the chromatin remodeling in β cells and thereby act as cis/trans-regulatory determinants of islet cell transcriptional programs.", "title": "Long non-coding RNAs as novel players in β cell function and type 1 diabetes" }, { "docid": "39506601", "text": "KLF1 (formerly known as EKLF) regulates the development of erythroid cells from bi-potent progenitor cells via the transcriptional activation of a diverse set of genes. Mice lacking Klf1 die in utero prior to E15 from severe anemia due to the inadequate expression of genes controlling hemoglobin production, cell membrane and cytoskeletal integrity, and the cell cycle. We have recently described the full repertoire of KLF1 binding sites in vivo by performing KLF1 ChIP-seq in primary erythroid tissue (E14.5 fetal liver). Here we describe the KLF1-dependent erythroid transcriptome by comparing mRNA-seq from Klf1(+/+) and Klf1(-/-) erythroid tissue. This has revealed novel target genes not previously obtainable by traditional microarray technology, and provided novel insights into the function of KLF1 as a transcriptional activator. We define a cis-regulatory module bound by KLF1, GATA1, TAL1, and EP300 that coordinates a core set of erythroid genes. We also describe a novel set of erythroid-specific promoters that drive high-level expression of otherwise ubiquitously expressed genes in erythroid cells. Our study has identified two novel lncRNAs that are dynamically expressed during erythroid differentiation, and discovered a role for KLF1 in directing apoptotic gene expression to drive the terminal stages of erythroid maturation.", "title": "Novel roles for KLF1 in erythropoiesis revealed by mRNA-seq." }, { "docid": "2380002", "text": "Increasing numbers of transcripts have been reported to transmit both protein-coding and regulatory information. Apart from challenging our conception of the gene, this observation raises the question as to what extent this phenomenon occurs across the genome and how and why such dual encoding of function has evolved in the eukaryotic genome. To address this question, we consider the evolutionary path of genes in the earliest forms of life on Earth, where it is generally regarded that proteins evolved from a cellular machinery based entirely within RNA. This led to the domination of protein-coding genes in the genomes of microorganisms, although it is likely that RNA never lost its other capacities and functionalities, as evidenced by cis-acting riboswitches and UTRs. On the basis that the subsequent evolution of a more sophisticated regulatory architecture to provide higher levels of epigenetic control and accurate spatiotemporal expression in developmentally complex organisms is a complicated task, we hypothesize: (i) that mRNAs have been and remain subject to secondary selection to provide trans-acting regulatory capability in parallel with protein-coding functions; (ii) that some and perhaps many protein-coding loci, possibly as a consequence of gene duplication, have lost protein-coding functions en route to acquiring more sophisticated trans-regulatory functions; (iii) that many transcripts have become subject to secondary processing to release different products; and (iv) that novel proteins have emerged within loci that previously evolved functionality as regulatory RNAs. In support of the idea that there is a dynamic flux between different types of informational RNAs in both evolutionary and real time, we review recent observations that have arisen from transcriptomic surveys of complex eukaryotes and reconsider how these observations impact on the notion that apparently discrete loci may express transcripts with more than one function. In conclusion, we posit that many eukaryotic loci have evolved the capacity to transact a multitude of overlapping and potentially independent functions as both regulatory and protein-coding RNAs.", "title": "The evolution of RNAs with multiple functions." }, { "docid": "51865482", "text": "BACKGROUND Adult mammalian heart loses regeneration ability following ischemic injury due to the loss of cardiomyocyte mitosis. However, the molecular mechanisms underlying the post-mitotic nature of cardiomyocytes remain largely unknown. \n OBJECTIVES The purpose of this study was to define the essential role of long noncoding ribonucleic acids (lncRNAs) in heart regeneration during postnatal and adult injury. \n METHODS Myh6-driving cardiomyocyte-specific lncRNA-CAREL transgenic mice and adenovirus-mediated in vivo silencing of endogenous CAREL were used in this study. The effect of CAREL on cardiomyocyte replication and heart regeneration after apical resection or myocardial infarction was assessed by detecting mitosis and cytokinesis. \n RESULTS An lncRNA CAREL was found significantly up-regulated in cardiomyocytes from neonatal mice (P7) in parallel with loss of regenerative capacity. Cardiac-specific overexpression of CAREL in mice reduced cardiomyocyte division and proliferation and blunted neonatal heart regeneration after injury. Conversely, silencing of CAREL in vivo markedly promoted cardiac regeneration and improved heart functions after myocardial infarction in neonatal and adult mice. CAREL acted as a competing endogenous ribonucleic acid for miR-296 to derepress the expression of Trp53inp1 and Itm2a, the target genes of miR-296. Consistently, overexpression of miR-296 significantly increased cardiomyocyte replication and cardiac regeneration after injury. Decline of cardiac regenerative ability in CAREL transgenic mice was also rescued by miR-296. A short fragment containing the conserved sequence of CAREL reduced the proliferation of human induced pluripotent stem cell-derived cardiomyocytes as the full-length CAREL. \n CONCLUSIONS LncRNA CAREL regulates cardiomyocyte proliferation and heart regeneration in postnatal and adult heart after injury by acting as a competing endogenous ribonucleic acid on miR-296 that targets Trp53inp1 and Itm2a.", "title": "The Long Noncoding RNA CAREL Controls Cardiac Regeneration." }, { "docid": "16806763", "text": "Increasing evidence suggests long non-coding RNAs (lncRNAs) are frequently aberrantly expressed in cancers, however, few related lncRNA signatures have been established for prediction of cancer prognosis. We aimed to develop a lncRNA signature to improve prognosis prediction of colorectal cancer (CRC). Using a lncRNA-mining approach, we performed lncRNA expression profiling in large CRC cohorts from Gene Expression Ominus (GEO), including GSE39582 test series(N=436), internal validation series (N=117); and two independent validation series GSE14333 (N=197) and GSE17536(N=145). We established a set of six lncRNAs that were significantly correlated with the disease free survival (DFS) in the test series. Based on this six-lncRNA signature, the test series patients could be classified into high-risk and low-risk subgroups with significantly different DFS (HR=2.670; P<0.0001). The prognostic value of this six-lncRNA signature was confirmed in the internal validation series and another two independent CRC sets. Gene set enrichment analysis (GSEA) analysis suggested that risk score positively correlated with several cancer metastasis related pathways. Functional experiments demonstrated three dysregulated lncRNAs, AK123657, BX648207 and BX649059 were required for efficient invasion and proliferation suppression in CRC cell lines. Our results might provide an efficient classification tool for clinical prognosis evaluation of CRC.", "title": "A long non-coding RNA signature to improve prognosis prediction of colorectal cancer" }, { "docid": "1667063", "text": "To elucidate the transcriptional 'landscape' that regulates human lymphoid commitment during postnatal life, we used RNA sequencing to assemble the long non-coding transcriptome across human bone marrow and thymic progenitor cells spanning the earliest stages of B lymphoid and T lymphoid specification. Over 3,000 genes encoding previously unknown long non-coding RNAs (lncRNAs) were revealed through the analysis of these rare populations. Lymphoid commitment was characterized by lncRNA expression patterns that were highly stage specific and were more lineage specific than those of protein-coding genes. Protein-coding genes co-expressed with neighboring lncRNA genes showed enrichment for ontologies related to lymphoid differentiation. The exquisite cell-type specificity of global lncRNA expression patterns independently revealed new developmental relationships among the earliest progenitor cells in the human bone marrow and thymus.", "title": "Long non-coding RNA profiling of human lymphoid progenitor cells reveals transcriptional divergence of B cell and T cell lineages" }, { "docid": "8148304", "text": "In the yeast Saccharomyces cerevisiae, genetic studies suggest that the RIM1 gene encodes a positive regulator of meiosis. rim1 mutations cause reduced expression of IME1, which is required for expression of many meiotic genes, and thus lead to a partial defect in meiosis and spore formation. We report the sequence of RIM1 and functional analysis of its coding region. The RIM1 gene product (RIM1) contains three regions similar to C2H2 zinc fingers. Serine substitutions for cysteine in each of the putative zinc fingers abolish RIM1 function. The carboxyl-terminus of RIM1 is enriched in acidic amino acids and is required for full RIM1 activity. RIM1 also contains two putative cAMP-dependent protein kinase (cAPK) phosphorylation sites. At one site, substitution of alanine for serine does not affect RIM1 activity; at the other site, this substitution impairs activity. This analysis of RIM1 suggests that the protein may function as a transcriptional activator. We have used the cloned RIM1 gene to create a complete rim1 deletion. This null allele, like previously isolated rim1 mutations, causes a partial meiotic defect. In addition to RIM1, maximum IME1 expression requires the MCK1 and IME4 gene products. Defects associated with rim1, mck1, and ime4 mutations in expression of a meiotic reporter gene (ime2-lacZ) and in sporulation are additive. These findings suggest that RIM1 acts independently of MCK1 and IME4 to stimulate IME1 expression.", "title": "Molecular characterization of the yeast meiotic regulatory gene RIM1." }, { "docid": "5519177", "text": "Long noncoding RNAs (lncRNAs) are emerging as critical regulators of gene expression in the immune system. Studies have shown that lncRNAs are expressed in a highly lineage-specific manner and control the differentiation and function of innate and adaptive cell types. In this Review, we focus on mechanisms used by lncRNAs to regulate genes encoding products involved in the immune response, including direct interactions with chromatin, RNA and proteins. In addition, we address new areas of lncRNA biology, such as the functions of enhancer RNAs, circular RNAs and chemical modifications to RNA in cellular processes. We emphasize critical gaps in knowledge and future prospects for the roles of lncRNAs in the immune system and autoimmune disease.", "title": "Gene regulation in the immune system by long noncoding RNAs" }, { "docid": "17416520", "text": "The transcriptional regulator Spx plays a key role in maintaining the redox homeostasis of Bacillus subtilis cells exposed to disulfide stress. Defects in Spx were previously shown to lead to differential expression of numerous genes but direct and indirect regulatory effects could not be distinguished. Here we identified 283 discrete chromosomal sites potentially bound by the Spx-RNA polymerase (Spx-RNAP) complex using chromatin immunoprecipitation of Spx. Three quarters of these sites were located near Sigma(A)-dependent promoters, and upon diamide treatment, the fraction of the Spx-RNAP complex increased in parallel with the number and occupancy of DNA sites. Correlation of Spx-RNAP-binding sites with gene differential expression in wild-type and Δspx strains exposed or not to diamide revealed that 144 transcription units comprising 275 genes were potentially under direct Spx regulation. Spx-controlled promoters exhibited an extended -35 box in which nucleotide composition at the -43/-44 positions strongly correlated with observed activation. In vitro transcription confirmed activation by oxidized Spx of seven newly identified promoters, of which one was also activated by reduced Spx. Our study globally characterized the Spx regulatory network, revealing its role in the basal expression of some genes and its complex interplay with other stress responses.", "title": "Genome-wide identification of genes directly regulated by the pleiotropic transcription factor Spx in Bacillus subtilis" }, { "docid": "4418070", "text": "Regulatory T (Treg) cells, characterized by expression of the transcription factor forkhead box P3 (Foxp3), maintain immune homeostasis by suppressing self-destructive immune responses. Foxp3 operates as a late-acting differentiation factor controlling Treg cell homeostasis and function, whereas the early Treg-cell-lineage commitment is regulated by the Akt kinase and the forkhead box O (Foxo) family of transcription factors. However, whether Foxo proteins act beyond the Treg-cell-commitment stage to control Treg cell homeostasis and function remains largely unexplored. Here we show that Foxo1 is a pivotal regulator of Treg cell function. Treg cells express high amounts of Foxo1 and display reduced T-cell-receptor-induced Akt activation, Foxo1 phosphorylation and Foxo1 nuclear exclusion. Mice with Treg-cell-specific deletion of Foxo1 develop a fatal inflammatory disorder similar in severity to that seen in Foxp3-deficient mice, but without the loss of Treg cells. Genome-wide analysis of Foxo1 binding sites reveals ∼300 Foxo1-bound target genes, including the pro-inflammatory cytokine Ifng, that do not seem to be directly regulated by Foxp3. These findings show that the evolutionarily ancient Akt–Foxo1 signalling module controls a novel genetic program indispensable for Treg cell function.", "title": "Novel Foxo1-dependent transcriptional programs control Treg cell function" }, { "docid": "45143088", "text": "Long non-coding RNAs (lncRNAs) are involved in regulating chromatin modifications, gene transcription, mRNA translation, and protein function. We recently reported a high variation in the basal expression levels of a panel of lncRNAs in HeLa and MCF-7 cells and their differential response to DNA damage induction. Here, we hypothesized that lncRNA molecules with different cellular expression may have a differential abundance in secreted exosomes, and their exosome levels would reflect cellular response to DNA damage. MALAT1, HOTAIR, lincRNA-p21, GAS5, TUG1, CCND1-ncRNA in exosomes secreted from cultured cells were characterized. A different expression pattern of lncRNAs in exosomes was seen compared to cells. RNA molecules with relative low expression levels (lincRNA-p21, HOTAIR, ncRNA-CCND1) were highly enriched in exosomes. TUG1 and GAS5 levels were moderately elevated in exosomes, whereas MALAT1--which was the most abundant molecule in cells--was present at levels comparable to its cellular levels. lincRNA-p21 and ncRNA-CCND1 were the main molecules; exosome levels of them best reflect the change of their cellular levels upon exposure of the cells to bleomycin-induced DNA damage. In conclusion, we provide evidence that lncRNAs have a differential abundance in exosomes, indicating a selective loading.", "title": "Long non-coding RNAs with low expression levels in cells are enriched in secreted exosomes." }, { "docid": "21622715", "text": "Transcriptional factors binding to cAMP-responsive elements (CREs) in the promoters of various genes belong to the basic domain-leucine zipper superfamily and are composed of three genes in mammals, CREB, CREM, and ATF-1. A large number of CREB, CREM, and ATF-1 proteins are generated by posttranscriptional events, mostly alternative splicing, and regulate gene expression by acting as activators or repressors. Activation is classically brought about by signaling-dependent phosphorylation of a key acceptor site (Ser133 in CREB) by a number of possible kinases, including PKA, CamKIV, and Rsk-2. Phosphorylation is the prerequisite for the interaction of CBP (CREB-binding protein), a co-activator that has also histone acetyltransferase activity. Repression may involve dynamic dephosphorylation of the activators and thus decreased association with CBP. Another pathway of transcriptional repression on CRE sites implicates the inducible repressor ICER (inducible cAMP early repressor), a product of the CREM gene. Being an inducible repressor, ICER is involved in autoregulatory feedback loops of transcription that govern the down-regulation of early response genes, such as the proto-oncogene c-fos. The liver represents a remarkable physiological setting where cAMP-responsive signaling plays a major role. Indeed, a finely tuned program of gene expression is triggered by partial hepatectomy, so that through specific checkpoints a coordinated regeneration of the tissue is obtained. Temporal kinetics of transcriptional activation after hepatectomy reveals a pattern of early induction for several genes, some of them controlled by the CREB/CREM transcription factors. An important role of CREM in liver physiology was suggested by the robust induction of ICER after partial hepatectomy. The delay in tissue regeneration in CREM-deficient mice confirmed the important function of this factor in regulating hepatocyte proliferation. As gene induction is accompanied by critical changes in chromatin organization, the deciphering of the specific modification codes that histones display during liver regeneration and physiology will provide exciting new insights into the dynamics of chromatin architecture.", "title": "Coupling cAMP signaling to transcription in the liver: pivotal role of CREB and CREM." }, { "docid": "2151983", "text": "Transcription factors (TFs) bind specifically to discrete regions of mammalian genomes called cis-regulatory elements. Among those are enhancers, which play key roles in regulation of gene expression during development and differentiation. Despite the recognized central regulatory role exerted by chromatin in control of TF functions, much remains to be learned regarding the chromatin structure of enhancers and how it is established. Here, we have analyzed on a genomic-scale enhancers that recruit FOXA1, a pioneer transcription factor that triggers transcriptional competency of these cis-regulatory sites. Importantly, we found that FOXA1 binds to genomic regions showing local DNA hypomethylation and that its cell-type-specific recruitment to chromatin is linked to differential DNA methylation levels of its binding sites. Using neural differentiation as a model, we showed that induction of FOXA1 expression and its subsequent recruitment to enhancers is associated with DNA demethylation. Concomitantly, histone H3 lysine 4 methylation is induced at these enhancers. These epigenetic changes may both stabilize FOXA1 binding and allow for subsequent recruitment of transcriptional regulatory effectors. Interestingly, when cloned into reporter constructs, FOXA1-dependent enhancers were able to recapitulate their cell type specificity. However, their activities were inhibited by DNA methylation. Hence, these enhancers are intrinsic cell-type-specific regulatory regions of which activities have to be potentiated by FOXA1 through induction of an epigenetic switch that includes notably DNA demethylation.", "title": "Epigenetic switch involved in activation of pioneer factor FOXA1-dependent enhancers." }, { "docid": "3329824", "text": "BACKGROUND Central nervous system (CNS) disease as the site of first relapse after exposure to adjuvant trastuzumab has been reported. We carried out comprehensive meta-analysis to determine the risk of CNS metastases as the first site of recurrence in patients with HER2-positive breast cancer who received adjuvant trastuzumab. \n METHODS Eligible studies include randomized trials of adjuvant trastuzumab administered for 1 year to patients with HER2-positive breast cancer who reported CNS metastases as first site of disease recurrence. Statistical analyses were conducted to calculate the incidence, relative risk (RR), and 95% confidence intervals (CIs) using fixed-effects inverse variance and random-effects models. \n RESULTS A total of 9020 patients were included. The incidence of CNS metastases as first site of disease recurrence in HER2-positive patients receiving adjuvant trastuzumab was 2.56% (95% CI 2.07% to 3.01%) compared with 1.94% (95% CI 1.54% to 2.38%) in HER2-positive patients who did not receive adjuvant trastuzumab. The RR of the CNS as first site of relapse in trastuzumab-treated patients was 1.35 (95% CI 1.02-1.78, P = 0.038) compared with control arms without trastuzumab therapy. The ratio of CNS metastases to total number of recurrence events was 16.94% (95% CI 10.85% to 24.07%) and 8.33% (95% CI 6.49% to 10.86%) for the trastuzumab-treated and control groups, respectively. No statistically significant differences were found based on trastuzumab schedule or median follow-up time. No evidence of publication bias was observed. \n CONCLUSIONS Adjuvant trastuzumab is associated with a significant increased risk of CNS metastases as the site of first recurrence in HER2-positive breast cancer patients.", "title": "Incidence and risk of central nervous system metastases as site of first recurrence in patients with HER2-positive breast cancer treated with adjuvant trastuzumab." }, { "docid": "16691520", "text": "The estrogen receptor is the master transcriptional regulator of breast cancer phenotype and the archetype of a molecular therapeutic target. We mapped all estrogen receptor and RNA polymerase II binding sites on a genome-wide scale, identifying the authentic cis binding sites and target genes, in breast cancer cells. Combining this unique resource with gene expression data demonstrates distinct temporal mechanisms of estrogen-mediated gene regulation, particularly in the case of estrogen-suppressed genes. Furthermore, this resource has allowed the identification of cis-regulatory sites in previously unexplored regions of the genome and the cooperating transcription factors underlying estrogen signaling in breast cancer.", "title": "Genome-wide analysis of estrogen receptor binding sites" }, { "docid": "20935673", "text": "Spatial boundaries of homeotic gene expression are initiated and maintained by two sets of transcriptional repressors: the gap gene products and the Polycomb group proteins. Previously, the Hunchback (HB) protein has been implicated in setting the anterior expression limit of the UBX homeotic protein in parasegment 6. Here we investigate DNA elements and trans-acting repressors that control spatial expression of the Abdominal-A (ABD-A) homeotic protein. Analysis of a 1.7-kb enhancer element [iab-2(1.7)] from the iab-2 regulatory region shows that in contrast to Ubx enhancer elements, both HB and Krüppel (KR) are required to set the ABD-A anterior boundary in parasegment 7. DNase I footprinting and site-directed mutagenesis show that HB and KR are direct regulators of this iab-2 enhancer. The single KR site can be moved to a new location 100 bp away and still maintain repressive activity, whereas relocation by 300 bp abolishes activity. These results suggest that KR repression occurs through a local quenching mechanism. We also show that the gap repressor Giant (GT) initially establishes a posterior expression limit at PS9, which shifts posteriorly after the blastoderm stage. Finally, we show that this iab-2 enhancer contains multiple binding sites for the Polycomb group protein Pleiohomeotic (PHO). These iab-2 PHO sites are required in vivo for chromosome pairing-dependent repression of a mini-white reporter. However, the PHO sites are not sufficient to maintain repression of a homeotic reporter gene anterior to PS7. Full maintenance at late embryonic stages requires additional sequences adjacent to the iab-2(1.7) enhancer.", "title": "Functional analysis of repressor binding sites in the iab-2 regulatory region of the abdominal-A homeotic gene." }, { "docid": "515489", "text": "UNLABELLED Many protein-coding oncofetal genes are highly expressed in murine and human fetal liver and silenced in adult liver. The protein products of these hepatic oncofetal genes have been used as clinical markers for the recurrence of hepatocellular carcinoma (HCC) and as therapeutic targets for HCC. Herein we examined the expression profiles of long noncoding RNAs (lncRNAs) found in fetal and adult liver in mice. Many fetal hepatic lncRNAs were identified; one of these, lncRNA-mPvt1, is an oncofetal RNA that was found to promote cell proliferation, cell cycling, and the expression of stem cell-like properties of murine cells. Interestingly, we found that human lncRNA-hPVT1 was up-regulated in HCC tissues and that patients with higher lncRNA-hPVT1 expression had a poor clinical prognosis. The protumorigenic effects of lncRNA-hPVT1 on cell proliferation, cell cycling, and stem cell-like properties of HCC cells were confirmed both in vitro and in vivo by gain-of-function and loss-of-function experiments. Moreover, mRNA expression profile data showed that lncRNA-hPVT1 up-regulated a series of cell cycle genes in SMMC-7721 cells. By RNA pulldown and mass spectrum experiments, we identified NOP2 as an RNA-binding protein that binds to lncRNA-hPVT1. We confirmed that lncRNA-hPVT1 up-regulated NOP2 by enhancing the stability of NOP2 proteins and that lncRNA-hPVT1 function depends on the presence of NOP2. \n CONCLUSION Our study demonstrates that the expression of many lncRNAs is up-regulated in early liver development and that the fetal liver can be used to search for new diagnostic markers for HCC. LncRNA-hPVT1 promotes cell proliferation, cell cycling, and the acquisition of stem cell-like properties in HCC cells by stabilizing NOP2 protein. Regulation of the lncRNA-hPVT1/NOP2 pathway may have beneficial effects on the treatment of HCC.", "title": "Oncofetal long noncoding RNA PVT1 promotes proliferation and stem cell-like property of hepatocellular carcinoma cells by stabilizing NOP2." }, { "docid": "25900857", "text": "Most theories used to explain the evolution of eusociality rest upon two key assumptions: mutations affecting the phenotype of sterile workers evolve by positive selection if the resulting traits benefit fertile kin, and that worker traits provide the primary mechanism allowing social insects to adapt to their environment. Despite the common view that positive selection drives phenotypic evolution of workers, we know very little about the prevalence of positive selection acting on the genomes of eusocial insects. We mapped the footprints of positive selection in Apis mellifera through analysis of 40 individual genomes, allowing us to identify thousands of genes and regulatory sequences with signatures of adaptive evolution over multiple timescales. We found Apoidea- and Apis-specific genes to be enriched for signatures of positive selection, indicating that novel genes play a disproportionately large role in adaptive evolution of eusocial insects. Worker-biased proteins have higher signatures of adaptive evolution relative to queen-biased proteins, supporting the view that worker traits are key to adaptation. We also found genes regulating worker division of labor to be enriched for signs of positive selection. Finally, genes associated with worker behavior based on analysis of brain gene expression were highly enriched for adaptive protein and cis-regulatory evolution. Our study highlights the significant contribution of worker phenotypes to adaptive evolution in social insects, and provides a wealth of knowledge on the loci that influence fitness in honey bees.", "title": "Population genomics of the honey bee reveals strong signatures of positive selection on worker traits." } ]

[ { "docid": "11328820", "text": "The early events leading to the development of rheumatoid arthritis (RA) remain unclear, but formation of autoantibodies to citrullinated protein antigens (ACPAs) is considered a key pathogenic event. Neutrophils isolated from patients with various autoimmune diseases display enhanced neutrophil extracellular trap (NET) formation, a phenomenon that exposes autoantigens in the context of immunostimulatory molecules. We investigated whether aberrant NETosis occurs in RA, determined its triggers, and examined its deleterious inflammatory consequences. Enhanced NETosis was observed in circulating and RA synovial fluid neutrophils compared to neutrophils from healthy controls and from patients with osteoarthritis (OA). Further, netting neutrophils infiltrated RA synovial tissue, rheumatoid nodules, and skin. NETosis correlated with ACPA presence and levels and with systemic inflammatory markers. RA sera and immunoglobulin fractions from RA patients with high levels of ACPA and/or rheumatoid factor significantly enhanced NETosis, and the NETs induced by these autoantibodies displayed distinct protein content. Indeed, during NETosis, neutrophils externalized the citrullinated autoantigens implicated in RA pathogenesis, and anti-citrullinated vimentin antibodies potently induced NET formation. Moreover, the inflammatory cytokines interleukin-17A (IL-17A) and tumor necrosis factor-α (TNF-α) induced NETosis in RA neutrophils. In turn, NETs significantly augmented inflammatory responses in RA and OA synovial fibroblasts, including induction of IL-6, IL-8, chemokines, and adhesion molecules. These observations implicate accelerated NETosis in RA pathogenesis, through externalization of citrullinated autoantigens and immunostimulatory molecules that may promote aberrant adaptive and innate immune responses in the joint and in the periphery, and perpetuate pathogenic mechanisms in this disease.", "title": "NETs are a source of citrullinated autoantigens and stimulate inflammatory responses in rheumatoid arthritis." }, { "docid": "30041340", "text": "BACKGROUND Histone deimination regulates gene function and contributes to antimicrobial response, allowing the formation of neutrophil extracellular traps (NETs). Deiminated proteins are target of anti-citrullinated peptides antibodies (ACPA) in rheumatoid arthritis (RA). \n OBJECTIVE The objective of this paper is to test the hypothesis that RA sera react with deiminated histones contained in NETs. \n METHODS Neutrophils from peripheral blood were stimulated with A23187 and acid treated; NETosis was induced by phorbol myristate acetate, and NET proteins were isolated. Sera were tested by immunoblot on acid extracted proteins from neutrophils and from NETs, and by ELISA on deiminated histone H4 or H4-derived peptides. Bands reactive with RA sera were excised from gels, digested with trypsin and subjected to matrix-assisted laser desorption/ionisation time of flight (MALDI-TOF) analysis, before and after derivatisation to detect citrullinated peptides. \n RESULTS RA sera reacted with a deiminated antigen of 11 KDa from activated neutrophils, recognised also by anti-H4 and antideiminated H4 antibodies. A similar reactivity was observed with NET proteins. The antigen from neutrophils or NETs was identified as citrullinated H4 by MALDI-TOF analysis. By ELISA, RA sera bound in vitro citrullinated H4. Citrullinated H4 14-34 and 31-50 peptides detected antibodies in 67% and 63% of RA sera and in less than 5% of controls; antibody titre was correlated with anti-CCP2. \n CONCLUSIONS Citrullinated H4 from activated neutrophils and NETs is a target of antibodies in RA, and synthetic citrullinated H4-derived peptides are a new substrate for ACPA detection. As NETosis can generate antigens for ACPA, these data suggest a novel connection between innate and adaptive immunity in RA.", "title": "Antibodies from patients with rheumatoid arthritis target citrullinated histone 4 contained in neutrophils extracellular traps." }, { "docid": "14853989", "text": "Autoantibodies to DNA and histones (chromatin) are the defining antigen specificity in systemic lupus erythematosus (SLE) and related musculoskeletal disorders but the mechanisms responsible for their induction remain mysterious. That situation rapidly changed once neutrophil extracellular chromatin traps (NETs) were discovered and observed to play a conserved role in innate immune responses to a broad variety of microbial pathogens. At the center of an infectious process, neutrophils exert various antimicrobial defenses, including the release of nuclear chromatin into the extracellular space. The externalized NETs, a complex meshwork of nuclear chromatin and antimicrobial proteins, serve to immobilize and degrade microbial pathogens. Here, we critically evaluate the evidence supporting NETs versus apoptotic bodies as a source for nuclear antigens in autoimmunity. We also discuss the possibility that NET chromatin forms an essential component of immune deposits in the pathogenesis of glomerulonephritis in SLE and other autoimmune immune complex diseases.", "title": "Neutrophil extracellular chromatin traps connect innate immune response to autoimmunity" } ]

[ { "docid": "17967608", "text": "Neutrophils trap and kill bacteria by forming highly decondensed chromatin structures, termed neutrophil extracellular traps (NETs). We previously reported that histone hypercitrullination catalyzed by peptidylarginine deiminase 4 (PAD4) correlates with chromatin decondensation during NET formation. However, the role of PAD4 in NET-mediated bacterial trapping and killing has not been tested. Here, we use PAD4 knockout mice to show that PAD4 is essential for NET-mediated antibacterial function. Unlike PAD4(+/+) neutrophils, PAD4(-/-) neutrophils cannot form NETs after stimulation with chemokines or incubation with bacteria, and are deficient in bacterial killing by NETs. In a mouse infectious disease model of necrotizing fasciitis, PAD4(-/-) mice are more susceptible to bacterial infection than PAD4(+/+) mice due to a lack of NET formation. Moreover, we found that citrullination decreased the bacterial killing activity of histones and nucleosomes, which suggests that PAD4 mainly plays a role in chromatin decondensation to form NETs instead of increasing histone-mediated bacterial killing. Our results define a role for histone hypercitrullination in innate immunity during bacterial infection.", "title": "PAD4 is essential for antibacterial innate immunity mediated by neutrophil extracellular traps" }, { "docid": "28149602", "text": "PURPOSE OF REVIEW Recent discoveries implicate neutrophils as important regulators of innate and adaptive immunity and in the development of organ damage in systemic autoimmune diseases, including systemic lupus erythematosus (SLE). RECENT FINDINGS Various putative SLE biomarkers are neutrophil-related, including neutrophil granular proteins and histones undergoing post-translational modifications during neutrophil extracellular trap (NET) formation. In the bone marrow, lupus neutrophils can drive B and T cell abnormalities, at least in part, by their enhanced production of type-I interferons, tumor necrosis factor-alpha (TNFα) and the B-cell stimulating factors B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL). Lupus neutrophils and, in particular, lupus low-density granulocytes (a distinct pathogenic subset) display epigenetic modifications and genomic alterations that may be relevant to their deleterious roles in SLE. Proteins and enzymes externalized by lupus NETs can affect vascular health by inducing endothelial apoptosis and oxidizing lipoproteins. Hampering NET formation through peptidylarginine deiminase inhibitors abrogates lupus phenotype and atherosclerosis in murine studies. SUMMARY Recent discoveries support the notion that neutrophils, low-density granulocytes and aberrant NET formation and clearance play important roles in lupus pathogenesis. Future studies should focus on how to selectively target these immunostimulatory pathways in this disease.", "title": "The role of neutrophils in the pathogenesis of systemic lupus erythematosus." }, { "docid": "36089763", "text": "Neutrophils phagocytose and kill microbes upon phagolysosomal fusion. Recently we found that activated neutrophils form extracellular fibres that consist of granule proteins and chromatin. These neutrophil extracellular traps (NETs) degrade virulence factors and kill Gram positive and negative bacteria. Here we show for the first time that Candida albicans, a eukaryotic pathogen, induces NET-formation and is susceptible to NET-mediated killing. C. albicans is the predominant aetiologic agent of fungal infections in humans, particularly in immunocompromised hosts. One major virulence trait of C. albicans is its ability to reversibly switch from singular budding cells to filamentous hyphae. We demonstrate that NETs kill both yeast-form and hyphal cells, and that granule components mediate fungal killing. Taken together our data indicate that neutrophils trap and kill ascomycetous yeasts by forming NETs.", "title": "Neutrophil extracellular traps capture and kill Candida albicans yeast and hyphal forms." }, { "docid": "1049501", "text": "Neutrophil extracellular traps (NETs) are implicated in autoimmunity, but how they are generated and their roles in sterile inflammation remain unclear. Ribonucleoprotein immune complexes (RNP ICs), inducers of NETosis, require mitochondrial reactive oxygen species (ROS) for maximal NET stimulation. After RNP IC stimulation of neutrophils, mitochondria become hypopolarized and translocate to the cell surface. Extracellular release of oxidized mitochondrial DNA is proinflammatory in vitro, and when this DNA is injected into mice, it stimulates type I interferon (IFN) signaling through a pathway dependent on the DNA sensor STING. Mitochondrial ROS are also necessary for spontaneous NETosis of low-density granulocytes from individuals with systemic lupus erythematosus. This was also observed in individuals with chronic granulomatous disease, who lack NADPH oxidase activity but still develop autoimmunity and type I IFN signatures. Mitochondrial ROS inhibition in vivo reduces disease severity and type I IFN responses in a mouse model of lupus. Together, these findings highlight a role for mitochondria in the generation not only of NETs but also of pro-inflammatory oxidized mitochondrial DNA in autoimmune diseases.", "title": "Neutrophil extracellular traps enriched in oxidized mitochondrial DNA are interferogenic and contribute to lupus-like disease" }, { "docid": "3330111", "text": "Neutrophils have long been viewed as the final effector cells of an acute inflammatory response, with a primary role in the clearance of extracellular pathogens. However, more recent evidence has extended the functions of these cells. The newly discovered repertoire of effector molecules in the neutrophil armamentarium includes a broad array of cytokines, extracellular traps and effector molecules of the humoral arm of the innate immune system. In addition, neutrophils are involved in the activation, regulation and effector functions of innate and adaptive immune cells. Accordingly, neutrophils have a crucial role in the pathogenesis of a broad range of diseases, including infections caused by intracellular pathogens, autoimmunity, chronic inflammation and cancer.", "title": "Neutrophils in the activation and regulation of innate and adaptive immunity" }, { "docid": "29399239", "text": "Neutrophil extracellular traps (NETs) are made of processed chromatin bound to granular and selected cytoplasmic proteins. NETs are released by white blood cells called neutrophils, maybe as a last resort, to control microbial infections. This release of chromatin is the result of a unique form of cell death, dubbed \"NETosis. \" Here we review our understanding of how NETs are made, their function in infections and as danger signals, and their emerging importance in autoimmunity and coagulation.", "title": "Neutrophil extracellular traps: Is immunity the second function of chromatin?" }, { "docid": "1800734", "text": "Upon activation, neutrophils release DNA fibers decorated with antimicrobial proteins, forming neutrophil extracellular traps (NETs). Although NETs are bactericidal and contribute to innate host defense, excessive NET formation has been linked to the pathogenesis of autoinflammatory diseases. However, the mechanisms regulating NET formation, particularly during chronic inflammation, are poorly understood. Here we show that the G protein–coupled receptor (GPCR) CXCR2 mediates NET formation. Downstream analyses showed that CXCR2-mediated NET formation was independent of NADPH oxidase and involved Src family kinases. We show the pathophysiological relevance of this mechanism in cystic fibrosis lung disease, characterized by chronic neutrophilic inflammation. We found abundant NETs in airway fluids of individuals with cystic fibrosis and mouse cystic fibrosis lung disease, and NET amounts correlated with impaired obstructive lung function. Pulmonary blockade of CXCR2 by intra-airway delivery of small-molecule antagonists inhibited NET formation and improved lung function in vivo without affecting neutrophil recruitment, proteolytic activity or antibacterial host defense. These studies establish CXCR2 as a receptor mediating NADPH oxidase–independent NET formation and provide evidence that this GPCR pathway is operative and druggable in cystic fibrosis lung disease.", "title": "CXCR2 mediates NADPH oxidase–independent neutrophil extracellular trap formation in cystic fibrosis airway inflammation" }, { "docid": "9878167", "text": "Neutrophil extracellular traps (NETs) represent extracellular structures able to bind and kill microorganisms. It is believed that they are generated by neutrophils undergoing cell death, allowing these dying or dead cells to kill microbes. We show that, following priming with granulocyte/macrophage colony-stimulating factor (GM-CSF) and subsequent short-term toll-like receptor 4 (TLR4) or complement factor 5a (C5a) receptor stimulation, viable neutrophils are able to generate NETs. Strikingly, NETs formed by living cells contain mitochondrial, but no nuclear, DNA. Pharmacological or genetic approaches to block reactive oxygen species (ROS) production suggested that NET formation is ROS dependent. Moreover, neutrophil populations stimulated with GM-CSF and C5a showed increased survival compared with resting neutrophils, which did not generate NETs. In conclusion, mitochondrial DNA release by neutrophils and NET formation do not require neutrophil death and do also not limit the lifespan of these cells.", "title": "Viable neutrophils release mitochondrial DNA to form neutrophil extracellular traps" }, { "docid": "43054703", "text": "Neutrophil extracellular traps (NETs) are webs of DNA covered with antimicrobial molecules that constitute a newly described killing mechanism in innate immune defense. Previous publications reported that NETs take up to 3-4 h to form via an oxidant-dependent event that requires lytic death of neutrophils. In this study, we describe neutrophils responding uniquely to Staphylococcus aureus via a novel process of NET formation that did not require neutrophil lysis or even breach of the plasma membrane. The multilobular nucleus rapidly became rounded and condensed. During this process, we observed the separation of the inner and outer nuclear membranes and budding of vesicles, and the separated membranes and vesicles were filled with nuclear DNA. The vesicles were extruded intact into the extracellular space where they ruptured, and the chromatin was released. This entire process occurred via a unique, very rapid (5-60 min), oxidant-independent mechanism. Mitochondrial DNA constituted very little if any of these NETs. They did have a limited amount of proteolytic activity and were able to kill S. aureus. With time, the nuclear envelope ruptured, and DNA filled the cytoplasm presumably for later lytic NET production, but this was distinct from the vesicular release mechanism. Panton-Valentine leukocidin, autolysin, and a lipase were identified in supernatants with NET-inducing activity, but Panton-Valentine leukocidin was the dominant NET inducer. We describe a new mechanism of NET release that is very rapid and contributes to trapping and killing of S. aureus.", "title": "A novel mechanism of rapid nuclear neutrophil extracellular trap formation in response to Staphylococcus aureus." }, { "docid": "24928817", "text": "The initiation and progression of adult-onset periodontitis has been associated with infection of the gingival sulcus by Porphyromonas gingivalis. This organism utilizes a multitude of virulence factors to evade host defenses as it establishes itself as one of the predominant pathogens in periodontal pockets. A feature common to many other oral pathogens is the production of ammonia due to its protective effect during acidic cleansing cycles in the mouth. Additionally, ammonia production by P. gingivalis has been proposed as a virulence factor due to its negative effects on neutrophil function. In this study, we describe the first purification of a peptidylarginine deiminase (PAD) from a prokaryote. PAD exhibits biochemical characteristics and properties that suggest that it may be a virulence agent. PAD deiminates the guanidino group of carboxyl-terminal arginine residues on a variety of peptides, including the vasoregulatory peptide-hormone bradykinin, to yield ammonia and a citrulline residue. The soluble protein has an apparent mass of 46 kDa, while the DNA sequence predicts a full-length protein of 61.7 kDa. PAD is optimally active at 55 degrees C, stable at low pH, and shows the greatest activity above pH 9.0. Interestingly, in the presence of stabilizing factors, PAD is resistant to limited proteolysis and retains significant activity after short-term boiling. We propose that PAD, acting in concert with arginine-specific proteinases from P. gingivalis, promotes the growth of the pathogen in the periodontal pocket, initially by enhancing its survivability and then by assisting the organism in its circumvention of host humoral defenses.", "title": "Purification, characterization, and sequence analysis of a potential virulence factor from Porphyromonas gingivalis, peptidylarginine deiminase." }, { "docid": "28015516", "text": "Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by a breakdown of tolerance to nuclear antigens and the development of immune complexes. Genomic approaches have shown that human SLE leukocytes homogeneously express type I interferon (IFN)-induced and neutrophil-related transcripts. Increased production and/or bioavailability of IFN-α and associated alterations in dendritic cell (DC) homeostasis have been linked to lupus pathogenesis. Although neutrophils have long been shown to be associated with lupus, their potential role in disease pathogenesis remains elusive. Here, we show that mature SLE neutrophils are primed in vivo by type I IFN and die upon exposure to SLE-derived anti-ribonucleoprotein antibodies, releasing neutrophil extracellular traps (NETs). SLE NETs contain DNA as well as large amounts of LL37 and HMGB1, neutrophil proteins that facilitate the uptake and recognition of mammalian DNA by plasmacytoid DCs (pDCs). Indeed, SLE NETs activate pDCs to produce high levels of IFN-α in a DNA- and TLR9 (Toll-like receptor 9)-dependent manner. Our results reveal an unsuspected role for neutrophils in SLE pathogenesis and identify a novel link between nucleic acid-recognizing antibodies and type I IFN production in this disease.", "title": "Netting neutrophils are major inducers of type I IFN production in pediatric systemic lupus erythematosus." }, { "docid": "20459964", "text": "Neutrophil is a key cell in pathophysiology of granulomatosis with polyangiitis. Recently, neutrophil extracellular traps were described in this disease. Mitochondrial DNA is also released during traps formation. We measured circulating cell-free mitochondrial and genomic DNA in serum of patients with granulomatosis with polyangiitis. Subjects with the disease (14 active and 11 in remission stage) and 10 healthy controls were enrolled. Quantitative real-time polymerase chain reaction (PCR) was used to measure 79 base pairs (bp) and 230 bp mtDNA fragments. Alu repeats were quantified to evaluate abundance of nuclear DNA in serum at the presence of plasmid control. Both fragments of mtDNA (79 bp and 230 bp) and genomic DNA were elevated significantly in granulomatosis with polyangiitis compared to controls. Only the shorter 79 bp mtDNA correlated with active stage of granulomatosis with polyangiitis and clinical symptoms. A mechanism of extracellular release of mitochondrial DNA accompanies the active stage of the disease. Circulating mtDNA is extremely high in untreated patients. This suggests that biomarker properties of mtDNA are useful for monitoring of treatment.", "title": "Circulating mitochondrial DNA in serum of patients with granulomatosis with polyangiitis." }, { "docid": "52925737", "text": "BACKGROUND Exosomes are extracellular vesicles that mediate cellular communication in health and diseases. Neutrophils could be polarized to a pro-tumor phenotype by tumor. The function of tumor-derived exosomes in neutrophil regulation remains unclear. \n METHODS We investigated the effects of gastric cancer cell-derived exosomes (GC-Ex) on the pro-tumor activation of neutrophils and elucidated the underlying mechanisms. \n RESULTS GC-Ex prolonged neutrophil survival and induced expression of inflammatory factors in neutrophils. GC-Ex-activated neutrophils, in turn, promoted gastric cancer cell migration. GC-Ex transported high mobility group box-1 (HMGB1) that activated NF-κB pathway through interaction with TLR4, resulting in an increased autophagic response in neutrophils. Blocking HMGB1/TLR4 interaction, NF-κB pathway, and autophagy reversed GC-Ex-induced neutrophil activation. Silencing HMGB1 in gastric cancer cells confirmed HMGB1 as a key factor for GC-Ex-mediated neutrophil activation. Furthermore, HMGB1 expression was upregulated in gastric cancer tissues. Increased HMGB1 expression was associated with poor prognosis in patients with gastric cancer. Finally, gastric cancer tissue-derived exosomes acted similarly as exosomes derived from gastric cancer cell lines in neutrophil activation. \n CONCLUSION We demonstrate that gastric cancer cell-derived exosomes induce autophagy and pro-tumor activation of neutrophils via HMGB1/TLR4/NF-κB signaling, which provides new insights into mechanisms for neutrophil regulation in cancer and sheds lights on the multifaceted role of exosomes in reshaping tumor microenvironment.", "title": "Tumor-derived exosomes induce N2 polarization of neutrophils to promote gastric cancer cell migration" }, { "docid": "17741440", "text": "Small-vessel vasculitis (SVV) is a chronic autoinflammatory condition linked to antineutrophil cytoplasm autoantibodies (ANCAs). Here we show that chromatin fibers, so-called neutrophil extracellular traps (NETs), are released by ANCA-stimulated neutrophils and contain the targeted autoantigens proteinase-3 (PR3) and myeloperoxidase (MPO). Deposition of NETs in inflamed kidneys and circulating MPO-DNA complexes suggest that NET formation triggers vasculitis and promotes the autoimmune response against neutrophil components in individuals with SVV.", "title": "Netting neutrophils in autoimmune small-vessel vasculitis" }, { "docid": "2236768", "text": "Neutrophil extracellular traps (NETs) are released as neutrophils die in vitro in a process requiring hours, leaving a temporal gap that invasive microbes may exploit. Neutrophils capable of migration and phagocytosis while undergoing NETosis have not been documented. During Gram-positive skin infections, we directly visualized live polymorphonuclear cells (PMNs) in vivo rapidly releasing NETs, which prevented systemic bacterial dissemination. NETosis occurred during crawling, thereby casting large areas of NETs. NET-releasing PMNs developed diffuse decondensed nuclei, ultimately becoming devoid of DNA. Cells with abnormal nuclei showed unusual crawling behavior highlighted by erratic pseudopods and hyperpolarization consistent with the nucleus being a fulcrum for crawling. A requirement for both Toll-like receptor 2 and complement-mediated opsonization tightly regulated NET release. Additionally, live human PMNs injected into mouse skin developed decondensed nuclei and formed NETS in vivo, and intact anuclear neutrophils were abundant in Gram-positive human abscesses. Therefore early in infection NETosis involves neutrophils that do not undergo lysis and retain the ability to multitask.", "title": "Infection-induced NETosis is a dynamic process involving neutrophil multitasking in vivo" }, { "docid": "46517055", "text": "Uncontrolled proteolysis by neutrophil serine proteases (NSPs) in lung secretions is a hallmark of cystic fibrosis (CF). We have shown that the active neutrophil elastase, protease 3, and cathepsin G in CF sputum resist inhibition in part by exogenous protease inhibitors. This resistance may be due to their binding to neutrophil extracellular traps (NETs) secreted by the activated neutrophils in CF sputum and to genomic DNA released from senescent and dead neutrophils. Treating CF sputum with DNase dramatically increases its elastase activity, which can then be stoichiometrically inhibited by exogenous elastase inhibitors. However, DNase treatment does not increase the activities of protease 3 and cathepsin G, indicating their different distribution and/or binding in CF sputum. Purified blood neutrophils secrete NETs when stimulated by the opportunistic CF bacteria Pseudomonas aeruginosa and Staphylococcus aureus. The activities of the three proteases were unchanged in these conditions, but subsequent DNase treatment produced a dramatic increase in all three proteolytic activities. Neutrophils activated with a calcium ionophore did not secrete NETs but released huge amounts of active proteases whose activities were not modified by DNase. We conclude that NETs are reservoirs of active proteases that protect them from inhibition and maintain them in a rapidly mobilizable status. Combining the effects of protease inhibitors with that of DNA-degrading agents could counter the deleterious proteolytic effects of NSPs in CF lung secretions.", "title": "Influence of DNA on the activities and inhibition of neutrophil serine proteases in cystic fibrosis sputum." }, { "docid": "28712203", "text": "Elastases of both the neutrophil and macrophage have been implicated in lung disease initiation and progression. Although it is unlikely that these proteases evolved for the purpose of injuring lung tissue, the elastin-rich connective tissue framework of the lungs appears to be particularly susceptible to the action of elastolytic proteases. Assuming that neutrophil elastase most likely plays a role in the migration of neutrophils toward a site of inflammation and degradation of proteins from invading organisms or other products of the inflammatory response, it is the role of inhibitors of this protease to protect normal tissues from its effects. In alpha-1 antitrypsin deficiency we find an experiment of nature that disrupts this protease-anti-protease balance, resulting in an increased risk of destructive lung disease.", "title": "Neutrophil elastase-mediated lung disease." } ]

[ { "docid": "11328820", "text": "The early events leading to the development of rheumatoid arthritis (RA) remain unclear, but formation of autoantibodies to citrullinated protein antigens (ACPAs) is considered a key pathogenic event. Neutrophils isolated from patients with various autoimmune diseases display enhanced neutrophil extracellular trap (NET) formation, a phenomenon that exposes autoantigens in the context of immunostimulatory molecules. We investigated whether aberrant NETosis occurs in RA, determined its triggers, and examined its deleterious inflammatory consequences. Enhanced NETosis was observed in circulating and RA synovial fluid neutrophils compared to neutrophils from healthy controls and from patients with osteoarthritis (OA). Further, netting neutrophils infiltrated RA synovial tissue, rheumatoid nodules, and skin. NETosis correlated with ACPA presence and levels and with systemic inflammatory markers. RA sera and immunoglobulin fractions from RA patients with high levels of ACPA and/or rheumatoid factor significantly enhanced NETosis, and the NETs induced by these autoantibodies displayed distinct protein content. Indeed, during NETosis, neutrophils externalized the citrullinated autoantigens implicated in RA pathogenesis, and anti-citrullinated vimentin antibodies potently induced NET formation. Moreover, the inflammatory cytokines interleukin-17A (IL-17A) and tumor necrosis factor-α (TNF-α) induced NETosis in RA neutrophils. In turn, NETs significantly augmented inflammatory responses in RA and OA synovial fibroblasts, including induction of IL-6, IL-8, chemokines, and adhesion molecules. These observations implicate accelerated NETosis in RA pathogenesis, through externalization of citrullinated autoantigens and immunostimulatory molecules that may promote aberrant adaptive and innate immune responses in the joint and in the periphery, and perpetuate pathogenic mechanisms in this disease.", "title": "NETs are a source of citrullinated autoantigens and stimulate inflammatory responses in rheumatoid arthritis." } ]

[ { "docid": "14853989", "text": "Autoantibodies to DNA and histones (chromatin) are the defining antigen specificity in systemic lupus erythematosus (SLE) and related musculoskeletal disorders but the mechanisms responsible for their induction remain mysterious. That situation rapidly changed once neutrophil extracellular chromatin traps (NETs) were discovered and observed to play a conserved role in innate immune responses to a broad variety of microbial pathogens. At the center of an infectious process, neutrophils exert various antimicrobial defenses, including the release of nuclear chromatin into the extracellular space. The externalized NETs, a complex meshwork of nuclear chromatin and antimicrobial proteins, serve to immobilize and degrade microbial pathogens. Here, we critically evaluate the evidence supporting NETs versus apoptotic bodies as a source for nuclear antigens in autoimmunity. We also discuss the possibility that NET chromatin forms an essential component of immune deposits in the pathogenesis of glomerulonephritis in SLE and other autoimmune immune complex diseases.", "title": "Neutrophil extracellular chromatin traps connect innate immune response to autoimmunity" }, { "docid": "30041340", "text": "BACKGROUND Histone deimination regulates gene function and contributes to antimicrobial response, allowing the formation of neutrophil extracellular traps (NETs). Deiminated proteins are target of anti-citrullinated peptides antibodies (ACPA) in rheumatoid arthritis (RA). \n OBJECTIVE The objective of this paper is to test the hypothesis that RA sera react with deiminated histones contained in NETs. \n METHODS Neutrophils from peripheral blood were stimulated with A23187 and acid treated; NETosis was induced by phorbol myristate acetate, and NET proteins were isolated. Sera were tested by immunoblot on acid extracted proteins from neutrophils and from NETs, and by ELISA on deiminated histone H4 or H4-derived peptides. Bands reactive with RA sera were excised from gels, digested with trypsin and subjected to matrix-assisted laser desorption/ionisation time of flight (MALDI-TOF) analysis, before and after derivatisation to detect citrullinated peptides. \n RESULTS RA sera reacted with a deiminated antigen of 11 KDa from activated neutrophils, recognised also by anti-H4 and antideiminated H4 antibodies. A similar reactivity was observed with NET proteins. The antigen from neutrophils or NETs was identified as citrullinated H4 by MALDI-TOF analysis. By ELISA, RA sera bound in vitro citrullinated H4. Citrullinated H4 14-34 and 31-50 peptides detected antibodies in 67% and 63% of RA sera and in less than 5% of controls; antibody titre was correlated with anti-CCP2. \n CONCLUSIONS Citrullinated H4 from activated neutrophils and NETs is a target of antibodies in RA, and synthetic citrullinated H4-derived peptides are a new substrate for ACPA detection. As NETosis can generate antigens for ACPA, these data suggest a novel connection between innate and adaptive immunity in RA.", "title": "Antibodies from patients with rheumatoid arthritis target citrullinated histone 4 contained in neutrophils extracellular traps." }, { "docid": "17967608", "text": "Neutrophils trap and kill bacteria by forming highly decondensed chromatin structures, termed neutrophil extracellular traps (NETs). We previously reported that histone hypercitrullination catalyzed by peptidylarginine deiminase 4 (PAD4) correlates with chromatin decondensation during NET formation. However, the role of PAD4 in NET-mediated bacterial trapping and killing has not been tested. Here, we use PAD4 knockout mice to show that PAD4 is essential for NET-mediated antibacterial function. Unlike PAD4(+/+) neutrophils, PAD4(-/-) neutrophils cannot form NETs after stimulation with chemokines or incubation with bacteria, and are deficient in bacterial killing by NETs. In a mouse infectious disease model of necrotizing fasciitis, PAD4(-/-) mice are more susceptible to bacterial infection than PAD4(+/+) mice due to a lack of NET formation. Moreover, we found that citrullination decreased the bacterial killing activity of histones and nucleosomes, which suggests that PAD4 mainly plays a role in chromatin decondensation to form NETs instead of increasing histone-mediated bacterial killing. Our results define a role for histone hypercitrullination in innate immunity during bacterial infection.", "title": "PAD4 is essential for antibacterial innate immunity mediated by neutrophil extracellular traps" }, { "docid": "17741440", "text": "Small-vessel vasculitis (SVV) is a chronic autoinflammatory condition linked to antineutrophil cytoplasm autoantibodies (ANCAs). Here we show that chromatin fibers, so-called neutrophil extracellular traps (NETs), are released by ANCA-stimulated neutrophils and contain the targeted autoantigens proteinase-3 (PR3) and myeloperoxidase (MPO). Deposition of NETs in inflamed kidneys and circulating MPO-DNA complexes suggest that NET formation triggers vasculitis and promotes the autoimmune response against neutrophil components in individuals with SVV.", "title": "Netting neutrophils in autoimmune small-vessel vasculitis" }, { "docid": "43054703", "text": "Neutrophil extracellular traps (NETs) are webs of DNA covered with antimicrobial molecules that constitute a newly described killing mechanism in innate immune defense. Previous publications reported that NETs take up to 3-4 h to form via an oxidant-dependent event that requires lytic death of neutrophils. In this study, we describe neutrophils responding uniquely to Staphylococcus aureus via a novel process of NET formation that did not require neutrophil lysis or even breach of the plasma membrane. The multilobular nucleus rapidly became rounded and condensed. During this process, we observed the separation of the inner and outer nuclear membranes and budding of vesicles, and the separated membranes and vesicles were filled with nuclear DNA. The vesicles were extruded intact into the extracellular space where they ruptured, and the chromatin was released. This entire process occurred via a unique, very rapid (5-60 min), oxidant-independent mechanism. Mitochondrial DNA constituted very little if any of these NETs. They did have a limited amount of proteolytic activity and were able to kill S. aureus. With time, the nuclear envelope ruptured, and DNA filled the cytoplasm presumably for later lytic NET production, but this was distinct from the vesicular release mechanism. Panton-Valentine leukocidin, autolysin, and a lipase were identified in supernatants with NET-inducing activity, but Panton-Valentine leukocidin was the dominant NET inducer. We describe a new mechanism of NET release that is very rapid and contributes to trapping and killing of S. aureus.", "title": "A novel mechanism of rapid nuclear neutrophil extracellular trap formation in response to Staphylococcus aureus." }, { "docid": "28149602", "text": "PURPOSE OF REVIEW Recent discoveries implicate neutrophils as important regulators of innate and adaptive immunity and in the development of organ damage in systemic autoimmune diseases, including systemic lupus erythematosus (SLE). RECENT FINDINGS Various putative SLE biomarkers are neutrophil-related, including neutrophil granular proteins and histones undergoing post-translational modifications during neutrophil extracellular trap (NET) formation. In the bone marrow, lupus neutrophils can drive B and T cell abnormalities, at least in part, by their enhanced production of type-I interferons, tumor necrosis factor-alpha (TNFα) and the B-cell stimulating factors B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL). Lupus neutrophils and, in particular, lupus low-density granulocytes (a distinct pathogenic subset) display epigenetic modifications and genomic alterations that may be relevant to their deleterious roles in SLE. Proteins and enzymes externalized by lupus NETs can affect vascular health by inducing endothelial apoptosis and oxidizing lipoproteins. Hampering NET formation through peptidylarginine deiminase inhibitors abrogates lupus phenotype and atherosclerosis in murine studies. SUMMARY Recent discoveries support the notion that neutrophils, low-density granulocytes and aberrant NET formation and clearance play important roles in lupus pathogenesis. Future studies should focus on how to selectively target these immunostimulatory pathways in this disease.", "title": "The role of neutrophils in the pathogenesis of systemic lupus erythematosus." }, { "docid": "36089763", "text": "Neutrophils phagocytose and kill microbes upon phagolysosomal fusion. Recently we found that activated neutrophils form extracellular fibres that consist of granule proteins and chromatin. These neutrophil extracellular traps (NETs) degrade virulence factors and kill Gram positive and negative bacteria. Here we show for the first time that Candida albicans, a eukaryotic pathogen, induces NET-formation and is susceptible to NET-mediated killing. C. albicans is the predominant aetiologic agent of fungal infections in humans, particularly in immunocompromised hosts. One major virulence trait of C. albicans is its ability to reversibly switch from singular budding cells to filamentous hyphae. We demonstrate that NETs kill both yeast-form and hyphal cells, and that granule components mediate fungal killing. Taken together our data indicate that neutrophils trap and kill ascomycetous yeasts by forming NETs.", "title": "Neutrophil extracellular traps capture and kill Candida albicans yeast and hyphal forms." }, { "docid": "1049501", "text": "Neutrophil extracellular traps (NETs) are implicated in autoimmunity, but how they are generated and their roles in sterile inflammation remain unclear. Ribonucleoprotein immune complexes (RNP ICs), inducers of NETosis, require mitochondrial reactive oxygen species (ROS) for maximal NET stimulation. After RNP IC stimulation of neutrophils, mitochondria become hypopolarized and translocate to the cell surface. Extracellular release of oxidized mitochondrial DNA is proinflammatory in vitro, and when this DNA is injected into mice, it stimulates type I interferon (IFN) signaling through a pathway dependent on the DNA sensor STING. Mitochondrial ROS are also necessary for spontaneous NETosis of low-density granulocytes from individuals with systemic lupus erythematosus. This was also observed in individuals with chronic granulomatous disease, who lack NADPH oxidase activity but still develop autoimmunity and type I IFN signatures. Mitochondrial ROS inhibition in vivo reduces disease severity and type I IFN responses in a mouse model of lupus. Together, these findings highlight a role for mitochondria in the generation not only of NETs but also of pro-inflammatory oxidized mitochondrial DNA in autoimmune diseases.", "title": "Neutrophil extracellular traps enriched in oxidized mitochondrial DNA are interferogenic and contribute to lupus-like disease" }, { "docid": "3330111", "text": "Neutrophils have long been viewed as the final effector cells of an acute inflammatory response, with a primary role in the clearance of extracellular pathogens. However, more recent evidence has extended the functions of these cells. The newly discovered repertoire of effector molecules in the neutrophil armamentarium includes a broad array of cytokines, extracellular traps and effector molecules of the humoral arm of the innate immune system. In addition, neutrophils are involved in the activation, regulation and effector functions of innate and adaptive immune cells. Accordingly, neutrophils have a crucial role in the pathogenesis of a broad range of diseases, including infections caused by intracellular pathogens, autoimmunity, chronic inflammation and cancer.", "title": "Neutrophils in the activation and regulation of innate and adaptive immunity" }, { "docid": "29399239", "text": "Neutrophil extracellular traps (NETs) are made of processed chromatin bound to granular and selected cytoplasmic proteins. NETs are released by white blood cells called neutrophils, maybe as a last resort, to control microbial infections. This release of chromatin is the result of a unique form of cell death, dubbed \"NETosis. \" Here we review our understanding of how NETs are made, their function in infections and as danger signals, and their emerging importance in autoimmunity and coagulation.", "title": "Neutrophil extracellular traps: Is immunity the second function of chromatin?" }, { "docid": "1800734", "text": "Upon activation, neutrophils release DNA fibers decorated with antimicrobial proteins, forming neutrophil extracellular traps (NETs). Although NETs are bactericidal and contribute to innate host defense, excessive NET formation has been linked to the pathogenesis of autoinflammatory diseases. However, the mechanisms regulating NET formation, particularly during chronic inflammation, are poorly understood. Here we show that the G protein–coupled receptor (GPCR) CXCR2 mediates NET formation. Downstream analyses showed that CXCR2-mediated NET formation was independent of NADPH oxidase and involved Src family kinases. We show the pathophysiological relevance of this mechanism in cystic fibrosis lung disease, characterized by chronic neutrophilic inflammation. We found abundant NETs in airway fluids of individuals with cystic fibrosis and mouse cystic fibrosis lung disease, and NET amounts correlated with impaired obstructive lung function. Pulmonary blockade of CXCR2 by intra-airway delivery of small-molecule antagonists inhibited NET formation and improved lung function in vivo without affecting neutrophil recruitment, proteolytic activity or antibacterial host defense. These studies establish CXCR2 as a receptor mediating NADPH oxidase–independent NET formation and provide evidence that this GPCR pathway is operative and druggable in cystic fibrosis lung disease.", "title": "CXCR2 mediates NADPH oxidase–independent neutrophil extracellular trap formation in cystic fibrosis airway inflammation" }, { "docid": "52925737", "text": "BACKGROUND Exosomes are extracellular vesicles that mediate cellular communication in health and diseases. Neutrophils could be polarized to a pro-tumor phenotype by tumor. The function of tumor-derived exosomes in neutrophil regulation remains unclear. \n METHODS We investigated the effects of gastric cancer cell-derived exosomes (GC-Ex) on the pro-tumor activation of neutrophils and elucidated the underlying mechanisms. \n RESULTS GC-Ex prolonged neutrophil survival and induced expression of inflammatory factors in neutrophils. GC-Ex-activated neutrophils, in turn, promoted gastric cancer cell migration. GC-Ex transported high mobility group box-1 (HMGB1) that activated NF-κB pathway through interaction with TLR4, resulting in an increased autophagic response in neutrophils. Blocking HMGB1/TLR4 interaction, NF-κB pathway, and autophagy reversed GC-Ex-induced neutrophil activation. Silencing HMGB1 in gastric cancer cells confirmed HMGB1 as a key factor for GC-Ex-mediated neutrophil activation. Furthermore, HMGB1 expression was upregulated in gastric cancer tissues. Increased HMGB1 expression was associated with poor prognosis in patients with gastric cancer. Finally, gastric cancer tissue-derived exosomes acted similarly as exosomes derived from gastric cancer cell lines in neutrophil activation. \n CONCLUSION We demonstrate that gastric cancer cell-derived exosomes induce autophagy and pro-tumor activation of neutrophils via HMGB1/TLR4/NF-κB signaling, which provides new insights into mechanisms for neutrophil regulation in cancer and sheds lights on the multifaceted role of exosomes in reshaping tumor microenvironment.", "title": "Tumor-derived exosomes induce N2 polarization of neutrophils to promote gastric cancer cell migration" }, { "docid": "9878167", "text": "Neutrophil extracellular traps (NETs) represent extracellular structures able to bind and kill microorganisms. It is believed that they are generated by neutrophils undergoing cell death, allowing these dying or dead cells to kill microbes. We show that, following priming with granulocyte/macrophage colony-stimulating factor (GM-CSF) and subsequent short-term toll-like receptor 4 (TLR4) or complement factor 5a (C5a) receptor stimulation, viable neutrophils are able to generate NETs. Strikingly, NETs formed by living cells contain mitochondrial, but no nuclear, DNA. Pharmacological or genetic approaches to block reactive oxygen species (ROS) production suggested that NET formation is ROS dependent. Moreover, neutrophil populations stimulated with GM-CSF and C5a showed increased survival compared with resting neutrophils, which did not generate NETs. In conclusion, mitochondrial DNA release by neutrophils and NET formation do not require neutrophil death and do also not limit the lifespan of these cells.", "title": "Viable neutrophils release mitochondrial DNA to form neutrophil extracellular traps" }, { "docid": "13578199", "text": "Human transglutaminase 2 (TG2), a member of a large family of enzymes that catalyze protein crosslinking, plays an important role in the extracellular matrix biology of many tissues and is implicated in the gluten-induced pathogenesis of celiac sprue. Although vertebrate transglutaminases have been studied extensively, thus far all structurally characterized members of this family have been crystallized in conformations with inaccessible active sites. We have trapped human TG2 in complex with an inhibitor that mimics inflammatory gluten peptide substrates and have solved, at 2-A resolution, its x-ray crystal structure. The inhibitor stabilizes TG2 in an extended conformation that is dramatically different from earlier transglutaminase structures. The active site is exposed, revealing that catalysis takes place in a tunnel, bridged by two tryptophan residues that separate acyl-donor from acyl-acceptor and stabilize the tetrahedral reaction intermediates. Site-directed mutagenesis was used to investigate the acyl-acceptor side of the tunnel, yielding mutants with a marked increase in preference for hydrolysis over transamidation. By providing the ability to visualize this activated conformer, our results create a foundation for understanding the catalytic as well as the non-catalytic roles of TG2 in biology, and for dissecting the process by which the autoantibody response to TG2 is induced in celiac sprue patients.", "title": "Transglutaminase 2 Undergoes a Large Conformational Change upon Activation " }, { "docid": "24928817", "text": "The initiation and progression of adult-onset periodontitis has been associated with infection of the gingival sulcus by Porphyromonas gingivalis. This organism utilizes a multitude of virulence factors to evade host defenses as it establishes itself as one of the predominant pathogens in periodontal pockets. A feature common to many other oral pathogens is the production of ammonia due to its protective effect during acidic cleansing cycles in the mouth. Additionally, ammonia production by P. gingivalis has been proposed as a virulence factor due to its negative effects on neutrophil function. In this study, we describe the first purification of a peptidylarginine deiminase (PAD) from a prokaryote. PAD exhibits biochemical characteristics and properties that suggest that it may be a virulence agent. PAD deiminates the guanidino group of carboxyl-terminal arginine residues on a variety of peptides, including the vasoregulatory peptide-hormone bradykinin, to yield ammonia and a citrulline residue. The soluble protein has an apparent mass of 46 kDa, while the DNA sequence predicts a full-length protein of 61.7 kDa. PAD is optimally active at 55 degrees C, stable at low pH, and shows the greatest activity above pH 9.0. Interestingly, in the presence of stabilizing factors, PAD is resistant to limited proteolysis and retains significant activity after short-term boiling. We propose that PAD, acting in concert with arginine-specific proteinases from P. gingivalis, promotes the growth of the pathogen in the periodontal pocket, initially by enhancing its survivability and then by assisting the organism in its circumvention of host humoral defenses.", "title": "Purification, characterization, and sequence analysis of a potential virulence factor from Porphyromonas gingivalis, peptidylarginine deiminase." }, { "docid": "27789588", "text": "Little is known about the etiologies of diseases associated with circulating antineutrophil cytoplasm autoantibodies (ANCA), such as primary vasculitides and inflammatory bowel diseases. However, the understanding of immune mechanisms supposedly involved in the pathogenesis of these diseases is still growing. In the present review, we first focus on the mechanisms triggering the development of ANCA, including the potential role of microbial superantigens and the possible defect(s) in the progression of apoptosis or in the removal of apoptotic cells. We next concentrate on the contribution of ANCA to the clinical symptoms and on the pathogenic role of ANCA, including the accessibility of ANCA antigens as targets for circulating antibodies and the mode of action of ANCA. Mechanisms of neutrophil activation by ANCA include the engagement of Fcgamma receptors, the possible mechanisms of neutrophil-mediated tissue damage, and the neutrophil-endothelial interaction.", "title": "Pathogenesis of diseases associated with antineutrophil cytoplasm autoantibodies." }, { "docid": "28015516", "text": "Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by a breakdown of tolerance to nuclear antigens and the development of immune complexes. Genomic approaches have shown that human SLE leukocytes homogeneously express type I interferon (IFN)-induced and neutrophil-related transcripts. Increased production and/or bioavailability of IFN-α and associated alterations in dendritic cell (DC) homeostasis have been linked to lupus pathogenesis. Although neutrophils have long been shown to be associated with lupus, their potential role in disease pathogenesis remains elusive. Here, we show that mature SLE neutrophils are primed in vivo by type I IFN and die upon exposure to SLE-derived anti-ribonucleoprotein antibodies, releasing neutrophil extracellular traps (NETs). SLE NETs contain DNA as well as large amounts of LL37 and HMGB1, neutrophil proteins that facilitate the uptake and recognition of mammalian DNA by plasmacytoid DCs (pDCs). Indeed, SLE NETs activate pDCs to produce high levels of IFN-α in a DNA- and TLR9 (Toll-like receptor 9)-dependent manner. Our results reveal an unsuspected role for neutrophils in SLE pathogenesis and identify a novel link between nucleic acid-recognizing antibodies and type I IFN production in this disease.", "title": "Netting neutrophils are major inducers of type I IFN production in pediatric systemic lupus erythematosus." }, { "docid": "20459964", "text": "Neutrophil is a key cell in pathophysiology of granulomatosis with polyangiitis. Recently, neutrophil extracellular traps were described in this disease. Mitochondrial DNA is also released during traps formation. We measured circulating cell-free mitochondrial and genomic DNA in serum of patients with granulomatosis with polyangiitis. Subjects with the disease (14 active and 11 in remission stage) and 10 healthy controls were enrolled. Quantitative real-time polymerase chain reaction (PCR) was used to measure 79 base pairs (bp) and 230 bp mtDNA fragments. Alu repeats were quantified to evaluate abundance of nuclear DNA in serum at the presence of plasmid control. Both fragments of mtDNA (79 bp and 230 bp) and genomic DNA were elevated significantly in granulomatosis with polyangiitis compared to controls. Only the shorter 79 bp mtDNA correlated with active stage of granulomatosis with polyangiitis and clinical symptoms. A mechanism of extracellular release of mitochondrial DNA accompanies the active stage of the disease. Circulating mtDNA is extremely high in untreated patients. This suggests that biomarker properties of mtDNA are useful for monitoring of treatment.", "title": "Circulating mitochondrial DNA in serum of patients with granulomatosis with polyangiitis." }, { "docid": "21487212", "text": "Ex-FABP, an extracellular fatty acid binding lipocalin, is physiologically expressed by differentiating chicken chondrocytes and myoblasts. Its expression is enhanced after cell treatment with inflammatory stimuli and repressed by anti-inflammatory agents, behaving as an acute phase protein. Chicken liver fragments in culture show enhanced protein expression after bacterial endotoxin treatment. To investigate the biological role of Ex-FABP, we stably transfected proliferating chondrocytes with an expression vector carrying antisense oriented Ex-FABP cDNA. We observed a dramatic loss of cell viability and a strong inhibition of cell proliferation and differentiation. When chondrocytes were transfected with the antisense oriented Ex-FABP cDNA we observed that Ex-FABP down-modulation increased apoptotic cell number. Myoblasts transfected with the same expression vector showed extensive cell death and impaired myotube formation. We suggest that Ex-FABP acts as a constitutive survival protein and that its expression and activation are fundamental to protect chondrocytes from cell death.", "title": "Inhibition of cell proliferation and induction of apoptosis by ExFABP gene targeting." } ]

[ { "docid": "2033917", "text": "Clathrin has an established function in the generation of vesicles that transfer membrane and proteins around the cell. The formation of clathrin-coated vesicles occurs continuously in non-dividing cells, but is shut down during mitosis, when clathrin concentrates at the spindle apparatus. Here, we show that clathrin stabilizes fibres of the mitotic spindle to aid congression of chromosomes. Clathrin bound to the spindle directly by the amino-terminal domain of clathrin heavy chain. Depletion of clathrin heavy chain using RNA interference prolonged mitosis; kinetochore fibres were destabilized, leading to defective congression of chromosomes to the metaphase plate and persistent activation of the spindle checkpoint. Normal mitosis was rescued by clathrin triskelia but not the N-terminal domain of clathrin heavy chain, indicating that stabilization of kinetochore fibres was dependent on the unique structure of clathrin. The importance of clathrin for normal mitosis may be relevant to understanding human cancers that involve gene fusions of clathrin heavy chain.", "title": "Clathrin is required for the function of the mitotic spindle" } ]

[ { "docid": "14205246", "text": "The spindle apparatus is a microtubule (MT)-based machinery that attaches to and segregates the chromosomes during mitosis and meiosis. Self-organization of the spindle around chromatin involves the assembly of MTs, their attachment to the chromosomes, and their organization into a bipolar array. One regulator of spindle self-organization is RanGTP. RanGTP is generated at chromatin and activates a set of soluble, Ran-regulated spindle factors such as TPX2, NuMA, and NuSAP . How the spindle factors direct and attach MTs to the chromosomes are key open questions. Nucleolar and Spindle-Associated Protein (NuSAP) was recently identified as an essential MT-stabilizing and bundling protein that is enriched at the central part of the spindle . Here, we show by biochemical reconstitution that NuSAP efficiently adsorbs to isolated chromatin and DNA and that it can directly produce and retain high concentrations of MTs in the immediate vicinity of chromatin or DNA. Moreover, our data reveal that NuSAP-chromatin interaction is subject to Ran regulation and can be suppressed by Importin alpha (Impalpha) and Imp7. We propose that the presence of MT binding agents such as NuSAP, which can be directly immobilized on chromatin, are critical for targeting MT production to vertebrate chromosomes during spindle self-organization.", "title": "A Role for NuSAP in Linking Microtubules to Mitotic Chromosomes" }, { "docid": "38127792", "text": "In mitosis the cell assembles the bipolar spindle, a microtubule (MT)-based apparatus that segregates the duplicated chromosomes into two daughter cells. Most animal cells enter mitosis with duplicated centrosomes that provide an active source of dynamic MTs. However, it is now established that spindle assembly relies on the nucleation of acentrosomal MTs occurring around the chromosomes after nuclear envelope breakdown, and on pre-existing microtubules. Where chromosome-dependent MT nucleation occurs, when MT amplification takes place and how the two pathways function are still key questions that generate some controversies. We reconcile the data and present an integrated model accounting for acentrosomal microtubule assembly in the dividing cell.", "title": "Acentrosomal Microtubule Assembly in Mitosis: The Where, When, and How." }, { "docid": "17805221", "text": "Sport fishermen keep tension on their lines to prevent hooked fish from releasing. A molecular version of this angler's trick, operating at kinetochores, ensures accuracy during mitosis: the mitotic spindle attaches randomly to chromosomes and then correctly bioriented attachments are stabilized due to the tension exerted on them by opposing microtubules. Incorrect attachments, which lack tension, are unstable and release quickly, allowing another chance for biorientation. Stabilization of molecular interactions by tension also occurs in other physiological contexts, such as cell adhesion, motility, hemostasis, and tissue morphogenesis. Here, we review models for the stabilization of kinetochore attachments with an eye toward emerging models for other force-activated systems. Although attention in the mitosis field has focused mainly on one kinase-based mechanism, multiple mechanisms may act together to stabilize properly bioriented kinetochores and some principles governing other tension-sensitive systems may also apply to kinetochores.", "title": "Catch and release: how do kinetochores hook the right microtubules during mitosis?" }, { "docid": "1684489", "text": "BACKGROUND Production of the GTP-bound form of the Ran GTPase (RanGTP) around chromosomes induces spindle assembly by activating nuclear localization signal (NLS)-containing proteins. Several NLS proteins have been identified as spindle assembly factors, but the complexity of the process led us to search for additional proteins with distinct roles in spindle assembly. \n RESULTS We identify a chromatin-remodeling ATPase, CHD4, as a RanGTP-dependent microtubule (MT)-associated protein (MAP). MT binding occurs via the region containing an NLS and chromatin-binding domains. In Xenopus egg extracts and cultured cells, CHD4 largely dissociates from mitotic chromosomes and partially localizes to the spindle. Immunodepletion of CHD4 from egg extracts significantly reduces the quantity of MTs produced around chromatin and prevents spindle assembly. CHD4 RNAi in both HeLa and Drosophila S2 cells induces defects in spindle assembly and chromosome alignment in early mitosis, leading to chromosome missegregation. Further analysis in egg extracts and in HeLa cells reveals that CHD4 is a RanGTP-dependent MT stabilizer. Moreover, the CHD4-containing NuRD complex promotes organization of MTs into bipolar spindles in egg extracts. Importantly, this function of CHD4 is independent of chromatin remodeling. \n CONCLUSIONS Our results uncover a new role for CHD4 as a MAP required for MT stabilization and involved in generating spindle bipolarity.", "title": "CHD4 Is a RanGTP-Dependent MAP that Stabilizes Microtubules and Regulates Bipolar Spindle Formation" }, { "docid": "600808", "text": "Cyclin A is a stable protein in S and G2 phases, but is destabilized when cells enter mitosis and is almost completely degraded before the metaphase to anaphase transition. Microinjection of antibodies against subunits of the anaphase-promoting complex/cyclosome (APC/C) or against human Cdc20 (fizzy) arrested cells at metaphase and stabilized both cyclins A and B1. Cyclin A was efficiently polyubiquitylated by Cdc20 or Cdh1-activated APC/C in vitro, but in contrast to cyclin B1, the proteolysis of cyclin A was not delayed by the spindle assembly checkpoint. The degradation of cyclin B1 was accelerated by inhibition of the spindle assembly checkpoint. These data suggest that the APC/C is activated as cells enter mitosis and immediately targets cyclin A for degradation, whereas the spindle assembly checkpoint delays the degradation of cyclin B1 until the metaphase to anaphase transition. The “destruction box” (D-box) of cyclin A is 10–20 residues longer than that of cyclin B. Overexpression of wild-type cyclin A delayed the metaphase to anaphase transition, whereas expression of cyclin A mutants lacking a D-box arrested cells in anaphase.", "title": "Anaphase-Promoting Complex/Cyclosome–Dependent Proteolysis of Human Cyclin a Starts at the Beginning of Mitosis and Is Not Subject to the Spindle Assembly Checkpoint" }, { "docid": "11020675", "text": "Megakaryocytes undergo a unique differentiation program, becoming polyploid through repeated cycles of DNA synthesis without concomitant cell division. However, the mechanism underlying this polyploidization remains totally unknown. It has been postulated that polyploidization is due to a skipping of mitosis after each round of DNA replication. We carried out immunohistochemical studies on mouse bone marrow megakaryocytes during thrombopoietin- induced polyploidization and found that during this process megakaryocytes indeed enter mitosis and progress through normal prophase, prometaphase, metaphase, and up to anaphase A, but not to anaphase B, telophase, or cytokinesis. It was clearly observed that multiple spindle poles were formed as the polyploid megakaryocytes entered mitosis; the nuclear membrane broke down during prophase; the sister chromatids were aligned on a multifaced plate, and the centrosomes were symmetrically located on either side of each face of the plate at metaphase; and a set of sister chromatids moved into the multiple centrosomes during anaphase A. We further noted that the pair of spindle poles in anaphase were located in close proximity to each other, probably because of the lack of outward movement of spindle poles during anaphase B. Thus, the reassembling nuclear envelope may enclose all the sister chromatids in a single nucleus at anaphase and then skip telophase and cytokinesis. These observations clearly indicate that polyploidization of megakaryocytes is not simply due to a skipping of mitosis, and that the megakaryocytes must have a unique regulatory mechanism in anaphase, e.g., factors regulating anaphase such as microtubule motor proteins might be involved in this polyploidization process.", "title": "Thrombopoietin-induced Polyploidization of Bone Marrow Megakaryocytes Is Due to a Unique Regulatory Mechanism in Late Mitosis " }, { "docid": "4398832", "text": "The most conspicuous event in the cell cycle is the alignment of chromosomes in metaphase. Chromosome alignment fosters faithful segregation through the formation of bi-oriented attachments of kinetochores to spindle microtubules. Notably, numerous kinetochore-microtubule (k-MT) attachment errors are present in early mitosis (prometaphase), and the persistence of those errors is the leading cause of chromosome mis-segregation in aneuploid human tumour cells that continually mis-segregate whole chromosomes and display chromosomal instability. How robust error correction is achieved in prometaphase to ensure error-free mitosis remains unknown. Here we show that k-MT attachments in prometaphase cells are considerably less stable than in metaphase cells. The switch to more stable k-MT attachments in metaphase requires the proteasome-dependent destruction of cyclin A in prometaphase. Persistent cyclin A expression prevents k-MT stabilization even in cells with aligned chromosomes. By contrast, k-MTs are prematurely stabilized in cyclin-A-deficient cells. Consequently, cells lacking cyclin A display higher rates of chromosome mis-segregation. Thus, the stability of k-MT attachments increases decisively in a coordinated fashion among all chromosomes as cells transit from prometaphase to metaphase. Cyclin A creates a cellular environment that promotes microtubule detachment from kinetochores in prometaphase to ensure efficient error correction and faithful chromosome segregation.", "title": "Cyclin A Regulates Kinetochore-Microtubules to Promote Faithful Chromosome Segregation" }, { "docid": "14119470", "text": "Ran is an abundant nuclear GTPase with a clear role in nuclear transport during interphase but with roles in mitotic regulation that are less well understood. The nucleotide-binding state of Ran is regulated by a GTPase activating protein, RanGAP1, and by a guanine nucleotide exchange factor, RCC1. Ran also interacts with a guanine nucleotide dissociation inhibitor, RanBP1. RanBP1 has a high affinity for GTP-bound Ran, and it acts as a cofactor for RanGAP1, increasing the rate of GAP-mediated GTP hydrolysis on Ran approximately tenfold. RanBP1 levels oscillate during the cell cycle [4], and increased concentrations of RanBP1 prolong mitosis in mammalian cells and in Xenopus egg extracts (our unpublished observations). We investigated how increased concentrations of RanBP1 disturb mitosis. We found that spindle assembly is dramatically disrupted when exogenous RanBP1 is added to M phase Xenopus egg extracts. We present evidence that the role of Ran in spindle assembly is independent of nuclear transport and is probably mediated through changes in microtubule dynamics.", "title": "The Ran GTPase regulates mitotic spindle assembly" }, { "docid": "13953762", "text": "The Plk1-interacting checkpoint helicase (PICH) protein localizes to ultrafine anaphase bridges (UFBs) in mitosis alongside a complex of DNA repair proteins, including the Bloom's syndrome protein (BLM). However, very little is known about the function of PICH or how it is recruited to UFBs. Using a combination of microfluidics, fluorescence microscopy, and optical tweezers, we have defined the properties of PICH in an in vitro model of an anaphase bridge. We show that PICH binds with a remarkably high affinity to duplex DNA, resulting in ATP-dependent protein translocation and extension of the DNA. Most strikingly, the affinity of PICH for binding DNA increases with tension-induced DNA stretching, which mimics the effect of the mitotic spindle on a UFB. PICH binding also appears to diminish force-induced DNA melting. We propose a model in which PICH recognizes and stabilizes DNA under tension during anaphase, thereby facilitating the resolution of entangled sister chromatids.", "title": "PICH: a DNA translocase specially adapted for processing anaphase bridge DNA." }, { "docid": "24558930", "text": "Although assembly of acentrosomal meiotic spindles has been extensively studied, little is known about the segregation of chromosomes on these spindles. Here, we show in Caenorhabditis elegans oocytes that the kinetochore protein, KNL-1, directs assembly of meiotic kinetochores that orient chromosomes. However, in contrast to mitosis, chromosome separation during meiotic anaphase is kinetochore-independent. Before anaphase, meiotic kinetochores and spindle poles disassemble along with the microtubules on the poleward side of chromosomes. During anaphase, microtubules then form between the separating chromosomes. Functional analysis implicated a set of proteins that localize to a ring-shaped domain between kinetochores during pre-anaphase spindle assembly and anaphase separation. These proteins are localized by the chromosomal passenger complex, which regulates the loss of meiotic chromosome cohesion. Thus, meiotic segregation in C. elegans is a two-stage process, where kinetochores orient chromosomes, but are then dispensable for their separation. We suggest that separation is controlled by a meiosis-specific chromosomal domain to coordinate cohesin removal and chromosome segregation.", "title": "A kinetochore-independent mechanism drives anaphase chromosome separation during acentrosomal meiosis" }, { "docid": "6472746", "text": "Chromosome segregation during cell division depends on stable attachment of kinetochores to spindle microtubules. Mitotic spindle formation and kinetochore-microtubule (K-MT) capture typically occur within minutes of nuclear envelope breakdown. In contrast, during meiosis I in mouse oocytes, formation of the acentrosomal bipolar spindle takes 3-4 h, and stabilization of K-MT attachments is delayed an additional 3-4 h. The mechanism responsible for this delay, which likely prevents stabilization of erroneous attachments during spindle formation, is unknown. Here we show that during meiosis I, attachments are regulated by CDK1 activity, which gradually increases through prometaphase and metaphase I. Partial reduction of CDK1 activity delayed formation of stable attachments, whereas a premature increase in CDK1 activity led to precocious formation of stable attachments and eventually lagging chromosomes at anaphase I. These results indicate that the slow increase in CDK1 activity in meiosis I acts as a timing mechanism to allow stable K-MT attachments only after bipolar spindle formation, thus preventing attachment errors.", "title": "Increased CDK1 activity determines the timing of kinetochore-microtubule attachments in meiosis I" }, { "docid": "7681810", "text": "Mitotic spindle assembly is mediated by two processes: a centrosomal and a chromosomal pathway. RanGTP regulates the latter process by releasing microtubule-associated proteins from inhibitory complexes. NuSAP, a microtubule- and DNA-binding protein, is a target of RanGTP and promotes the formation of microtubules near chromosomes. However, the contribution of NuSAP to cell proliferation in vivo is unknown. Here, we demonstrate that the expression of NuSAP highly correlates with cell proliferation during embryogenesis and adult life, making it a reliable marker of proliferating cells. Additionally, we show that NuSAP deficiency in mice leads to early embryonic lethality. Spindle assembly in NuSAP-deficient cells is highly inefficient and chromosomes remain dispersed in the mitotic cytoplasm. As a result of sustained spindle checkpoint activity, the cells are unable to progress through mitosis, eventually leading to caspase activation and apoptotic cell death. Together, our findings demonstrate that NuSAP is essential for proliferation of embryonic cells and, simultaneously, they underscore the importance of chromatin-induced spindle assembly.", "title": "NuSAP is essential for chromatin-induced spindle formation during early embryogenesis." }, { "docid": "11041152", "text": "Molecular motors play critical roles in the formation of mitotic spindles, either through controlling the stability of individual microtubules, or by crosslinking and sliding microtubule arrays. Kinesin-8 motors are best known for their regulatory roles in controlling microtubule dynamics. They contain microtubule-destabilizing activities, and restrict spindle length in a wide variety of cell types and organisms. Here, we report an antiparallel microtubule-sliding activity of the budding yeast kinesin-8, Kip3. The in vivo importance of this sliding activity was established through the identification of complementary Kip3 mutants that separate the sliding activity and microtubule-destabilizing activity. In conjunction with Cin8, a kinesin-5 family member, the sliding activity of Kip3 promotes bipolar spindle assembly and the maintenance of genome stability. We propose a slide-disassemble model where the sliding and destabilizing activity of Kip3 balance during pre-anaphase. This facilitates normal spindle assembly. However, the destabilizing activity of Kip3 dominates in late anaphase, inhibiting spindle elongation and ultimately promoting spindle disassembly.", "title": "Microtubule sliding activity of a kinesin-8 promotes spindle assembly and spindle length control" }, { "docid": "11674596", "text": "A putative spindle matrix has been hypothesized to mediate chromosome motion, but its existence and functionality remain controversial. In this report, we show that Megator (Mtor), the Drosophila melanogaster counterpart of the human nuclear pore complex protein translocated promoter region (Tpr), and the spindle assembly checkpoint (SAC) protein Mad2 form a conserved complex that localizes to a nuclear derived spindle matrix in living cells. Fluorescence recovery after photobleaching experiments supports that Mtor is retained around spindle microtubules, where it shows distinct dynamic properties. Mtor/Tpr promotes the recruitment of Mad2 and Mps1 but not Mad1 to unattached kinetochores (KTs), mediating normal mitotic duration and SAC response. At anaphase, Mtor plays a role in spindle elongation, thereby affecting normal chromosome movement. We propose that Mtor/Tpr functions as a spatial regulator of the SAC, which ensures the efficient recruitment of Mad2 to unattached KTs at the onset of mitosis and proper spindle maturation, whereas enrichment of Mad2 in a spindle matrix helps confine the action of a diffusible \"wait anaphase\" signal to the vicinity of the spindle.", "title": "Spatiotemporal control of mitosis by the conserved spindle matrix protein Megator" }, { "docid": "493346", "text": "How sister kinetochores attach to microtubules from opposite spindle poles during mitosis (bi-orientation) remains poorly understood. In yeast, the ortholog of the Aurora B-INCENP protein kinase complex (Ipl1-Sli15) may have a role in this crucial process, because it is necessary to prevent attachment of sister kinetochores to microtubules from the same spindle pole. We investigated IPL1 function in cells that cannot replicate their chromosomes but nevertheless duplicate their spindle pole bodies (SPBs). Kinetochores detach from old SPBs and reattach to old and new SPBs with equal frequency in IPL1+ cells, but remain attached to old SPBs in ipl1 mutants. This raises the possibility that Ipl1-Sli15 facilitates bi-orientation by promoting turnover of kinetochore-SPB connections until traction of sister kinetochores toward opposite spindle poles creates tension in the surrounding chromatin.", "title": "Evidence that the Ipl1-Sli15 (Aurora Kinase-INCENP) Complex Promotes Chromosome Bi-orientation by Altering Kinetochore-Spindle Pole Connections" }, { "docid": "7114092", "text": "Megakaryocyte (MK) is the naturally polyploid cell that gives rise to platelets. Polyploidization occurs by endomitosis, which was a process considered to be an incomplete mitosis aborted in anaphase. Here, we used time-lapse confocal video microscopy to visualize the endomitotic process of primary human megakaryocytes. Our results show that the switch from mitosis to endomitosis corresponds to a late failure of cytokinesis accompanied by a backward movement of the 2 daughter cells. No abnormality was observed in the central spindle of endomitotic MKs. A furrow formation was present, but the contractile ring was abnormal because accumulation of nonmuscle myosin IIA was lacking. In addition, a defect in cell elongation was observed in dipolar endomitotic MKs during telophase. RhoA and F-actin were partially concentrated at the site of furrowing. Inhibition of the Rho/Rock pathway caused the disappearance of F-actin at midzone and increased MK ploidy level. This inhibition was associated with a more pronounced defect in furrow formation as well as in spindle elongation. Our results suggest that the late failure of cytokinesis responsible for the endomitotic process is related to a partial defect in the Rho/Rock pathway activation.", "title": "From bloodjournal.hematologylibrary.org at PENN STATE UNIVERSITY on February 23, 2013. For personal use only." }, { "docid": "4421746", "text": "Polyploidy, increased sets of chromosomes, occurs during development, cellular stress, disease and evolution. Despite its prevalence, little is known about the physiological alterations that accompany polyploidy. We previously described ‘ploidy-specific lethality’, where a gene deletion that is not lethal in haploid or diploid budding yeast causes lethality in triploids or tetraploids. Here we report a genome-wide screen to identify ploidy-specific lethal functions. Only 39 out of 3,740 mutations screened exhibited ploidy-specific lethality. Almost all of these mutations affect genomic stability by impairing homologous recombination, sister chromatid cohesion, or mitotic spindle function. We uncovered defects in wild-type tetraploids predicted by the screen, and identified mechanisms by which tetraploidization affects genomic stability. We show that tetraploids have a high incidence of syntelic/monopolar kinetochore attachments to the spindle pole. We suggest that this defect can be explained by mismatches in the ability to scale the size of the spindle pole body, spindle and kinetochores. Thus, geometric constraints may have profound effects on genome stability; the phenomenon described here may be relevant in a variety of biological contexts, including disease states such as cancer.", "title": "Genome-wide genetic analysis of polyploidy in yeast" }, { "docid": "2991954", "text": "Production of Ran-guanosine triphosphate (GTP) around chromosomes induces local nucleation and plus end stabilization of microtubules (MTs). The nuclear protein TPX2 is required for RanGTP-dependent MT nucleation. To find the MT stabilizer, we affinity purify nuclear localization signal (NLS)-containing proteins from Xenopus laevis egg extracts. This NLS protein fraction contains the MT stabilization activity. After further purification, we used mass spectrometry to identify proteins in active fractions, including cyclin-dependent kinase 11 (Cdk11). Cdk11 localizes on spindle poles and MTs in Xenopus culture cells and egg extracts. Recombinant Cdk11 demonstrates RanGTP-dependent MT stabilization activity, whereas a kinase-dead mutant does not. Inactivation of Cdk11 in egg extracts blocks RanGTP-dependent MT stabilization and dramatically decreases the spindle assembly rate. Simultaneous depletion of TPX2 completely inhibits centrosome-dependent spindle assembly. Our results indicate that Cdk11 is responsible for RanGTP-dependent MT stabilization around chromosomes and that this local stabilization is essential for normal rates of spindle assembly and spindle function.", "title": "Cdk11 is a RanGTP-dependent microtubule stabilization factor that regulates spindle assembly rate" }, { "docid": "24555417", "text": "In many species, oocyte meiosis is carried out in the absence of centrioles. As a result, microtubule organization, spindle assembly, and chromosome segregation proceed by unique mechanisms. Here, we report insights into the principles underlying this specialized form of cell division, through studies of C. elegans KLP-15 and KLP-16, two highly homologous members of the kinesin-14 family of minus-end-directed kinesins. These proteins localize to the acentriolar oocyte spindle and promote microtubule bundling during spindle assembly; following KLP-15/16 depletion, microtubule bundles form but then collapse into a disorganized array. Surprisingly, despite this defect we found that during anaphase, microtubules are able to reorganize into a bundled array that facilitates chromosome segregation. This phenotype therefore enabled us to identify factors promoting microtubule organization during anaphase, whose contributions are normally undetectable in wild-type worms; we found that SPD-1 (PRC1) bundles microtubules and KLP-18 (kinesin-12) likely sorts those bundles into a functional orientation capable of mediating chromosome segregation. Therefore, our studies have revealed an interplay between distinct mechanisms that together promote spindle formation and chromosome segregation in the absence of structural cues such as centrioles.", "title": "Interplay between microtubule bundling and sorting factors ensures acentriolar spindle stability during C. elegans oocyte meiosis" } ]

[ { "docid": "22405338", "text": "Kinetochores attach the replicated chromosomes to the mitotic spindle and orchestrate their transmission to the daughter cells. Kinetochore–spindle binding and chromosome segregation are mediated by the multi-copy KNL1Spc105, MIS12Mtw1 and NDC80Ndc80 complexes that form the so-called KMN network. KMN–spindle attachment is regulated by the Aurora BIpl1 and MPS1Mps1 kinases. It is unclear whether other mechanisms exist that support KMN activity during the cell cycle. Using budding yeast, we show that kinetochore protein Cnn1 localizes to the base of the Ndc80 complex and promotes a functionally competent configuration of the KMN network. Cnn1 regulates KMN activity in a spatiotemporal manner by inhibiting the interaction between its complexes. Cnn1 activity peaks in anaphase and is driven by the Cdc28, Mps1 and Ipl1 kinases.", "title": "Cnn1 inhibits the interactions between the KMN complexes of the yeast kinetochore" } ]

[ { "docid": "7878807", "text": "The Ndc80 complex is the key microtubule-binding element of the kinetochore. In contrast to the well-characterized interaction of Ndc80-Nuf2 heads with microtubules, little is known about how the Spc24-25 heterodimer connects to centromeric chromatin. Here, we present molecular details of Spc24-25 in complex with the histone-fold protein Cnn1/CENP-T illustrating how this connection ultimately links microtubules to chromosomes. The conserved Ndc80 receptor motif of Cnn1 is bound as an α helix in a hydrophobic cleft at the interface between Spc24 and Spc25. Point mutations that disrupt the Ndc80-Cnn1 interaction also abrogate binding to the Mtw1 complex and are lethal in yeast. We identify a Cnn1-related motif in the Dsn1 subunit of the Mtw1 complex, necessary for Ndc80 binding and essential for yeast growth. Replacing this region with the Cnn1 peptide restores viability demonstrating functionality of the Ndc80-binding module in different molecular contexts. Finally, phosphorylation of the Cnn1 N-terminus coordinates the binding of the two competing Ndc80 interaction partners. Together, our data provide structural insights into the modular binding mechanism of the Ndc80 complex to its centromere recruiters.", "title": "A structural basis for kinetochore recruitment of the Ndc80 complex via two distinct centromere receptors." }, { "docid": "18374364", "text": "A rare set of hematopoietic stem cells (HSC) must undergo a massive expansion to produce mature blood cells. The phenotypic isolation of HSC from mice offers the opportunity to determine directly their proliferation kinetics. We analyzed the proliferation and cell cycle kinetics of long-term self-renewing HSC (LT-HSC) in normal adult mice. At any one time, approximately 5% of LT-HSC were in S/G2/M phases of the cell cycle and another 20% were in G1 phase. BrdUrd incorporation was used to determine the rate at which different cohorts of HSC entered the cell cycle over time. About 50% of LT-HSC incorporated BrdUrd by 6 days and >90% incorporated BrdUrd by 30 days. By 6 months, 99% of LT-HSC had incorporated BrdUrd. We calculated that approximately 8% of LT-HSC asynchronously entered the cell cycle per day. Nested reverse transcription-PCR analysis revealed cyclin D2 expression in a high proportion of LT-HSC. Although approximately 75% of LT-HSC are quiescent in G0 at any one time, all HSC are recruited into cycle regularly such that 99% of LT-HSC divide on average every 57 days.", "title": "In vivo proliferation and cell cycle kinetics of long-term self-renewing hematopoietic stem cells." }, { "docid": "12232678", "text": "Recent reports have suggested that birds lack a mechanism of wholesale dosage compensation for the Z sex chromosome. This discovery was rather unexpected, as all other animals investigated with chromosomal mechanisms of sex determination have some method to counteract the effects of gene dosage of the dominant sex chromosome in males and females. Despite the lack of a global mechanism of avian dosage compensation, the pattern of gene expression difference between males and females varies a great deal for individual Z-linked genes. This suggests that some genes may be individually dosage compensated, and that some less-than-global pattern of dosage compensation, such as local or temporal, exists on the avian Z chromosome. We used global gene expression profiling in males and females for both somatic and gonadal tissue at several time points in the life cycle of the chicken to assess the pattern of sex-biased gene expression on the Z chromosome. Average fold-change between males and females varied somewhat among tissue time-point combinations, with embryonic brain samples having the smallest gene dosage effects, and adult gonadal tissue having the largest degree of male bias. Overall, there were no neighborhoods of overall dosage compensation along the Z. Taken together, this suggests that dosage compensation is regulated on the Z chromosome entirely on a gene-by-gene level, and can vary during the life cycle and by tissue type. This regulation may be an indication of how critical a given gene's functionality is, as the expression level for essential genes will be tightly regulated in order to avoid perturbing important pathways and networks with differential expression levels in males and females.", "title": "All dosage compensation is local: Gene-by-gene regulation of sex-biased expression on the chicken Z chromosome" }, { "docid": "11968641", "text": "BACKGROUND Circadian clocks control cell cycle factors, and circadian disruption promotes cancer. To address whether enhancing circadian rhythmicity in tumor cells affects cell cycle progression and reduces proliferation, we compared growth and cell cycle events of B16 melanoma cells and tumors with either a functional or dysfunctional clock. \n RESULTS We found that clock genes were suppressed in B16 cells and tumors, but treatments inducing circadian rhythmicity, such as dexamethasone, forskolin and heat shock, triggered rhythmic clock and cell cycle gene expression, which resulted in fewer cells in S phase and more in G1 phase. Accordingly, B16 proliferation in vitro and tumor growth in vivo was slowed down. Similar effects were observed in human colon carcinoma HCT-116 cells. Notably, the effects of dexamethasone were not due to an increase in apoptosis nor to an enhancement of immune cell recruitment to the tumor. Knocking down the essential clock gene Bmal1 in B16 tumors prevented the effects of dexamethasone on tumor growth and cell cycle events. \n CONCLUSIONS Here we demonstrated that the effects of dexamethasone on cell cycle and tumor growth are mediated by the tumor-intrinsic circadian clock. Thus, our work reveals that enhancing circadian clock function might represent a novel strategy to control cancer progression.", "title": "Enhancing circadian clock function in cancer cells inhibits tumor growth" }, { "docid": "10165258", "text": "Maintaining hematopoietic stem cell (HSC) quiescence is a critical property for the life-long generation of blood cells. Approximately 75% of cells in a highly enriched long-term repopulating HSC (LT-HSC) pool (Lin(-)Sca1(+)c-Kit(hi)CD150(+)CD48(-)) are quiescent, with only a small percentage of the LT-HSCs in cycle. Transcription factor GATA-3 is known to be vital for the development of T cells at multiple stages in the thymus and for Th2 differentiation in the peripheral organs. Although it is well documented that GATA-3 is expressed in HSCs, a role for GATA-3 in any prethymic progenitor cell has not been established. In the present study, we show that Gata3-null mutant mice generate fewer LT-HSCs and that fewer Gata3-null LT-HSCs are in cycle. Furthermore, Gata3 mutant hematopoietic progenitor cells fail to be recruited into an increased cycling state after 5-fluorouracil-induced myelosuppression. Therefore, GATA-3 is required for the maintenance of a normal number of LT-HSCs and for their entry into the cell cycle.", "title": "GATA-3 regulates hematopoietic stem cell maintenance and cell-cycle entry." }, { "docid": "7560876", "text": "Centrosomes are microtubule-organizing centres of animal cells. They influence the morphology of the microtubule cytoskeleton, function as the base for the primary cilium and serve as a nexus for important signalling pathways. At the core of a typical centrosome are two cylindrical microtubule-based structures termed centrioles, which recruit a matrix of associated pericentriolar material. Cells begin the cell cycle with exactly one centrosome, and the duplication of centrioles is constrained such that it occurs only once per cell cycle and at a specific site in the cell. As a result of this duplication mechanism, the two centrioles differ in age and maturity, and thus have different functions; for example, the older of the two centrioles can initiate the formation of a ciliary axoneme. We discuss spatial aspects of the centrosome duplication cycle, the mechanism of centriole assembly and the possible consequences of the inherent asymmetry of centrioles and centrosomes.", "title": "The centrosome cycle: Centriole biogenesis, duplication and inherent asymmetries" }, { "docid": "14550841", "text": "Hematopoietic stem cells (HSCs) in adult marrow are believed to be derived from fetal liver precursors. To study cell kinetics involved in long-term hematopoiesis, we studied single-sorted candidate HSCs from fetal liver that were cultured in the presence of a mixture of stimulatory cytokines. After 8–10 d, the number of cells in primary cultures varied from 10,000 cells. Single cells in slow growing colonies were recloned upon reaching a 100–200 cell stage. Strikingly, the number of cells in subclones varied widely again. These results are indicative of asymmetric divisions in primitive hematopoietic cells in which proliferative potential and cell cycle properties are unevenly distributed among daughter cells. The continuous generation of functional heterogeneity among the clonal progeny of HSCs is in support of intrinsic control of stem cell fate and provides a model for the long-term maintenance of hematopoiesis in vitro and in vivo.", "title": "Asymmetric Cell Divisions Sustain Long-Term Hematopoiesis from Single-sorted Human Fetal Liver Cells " }, { "docid": "7492420", "text": "Human embryonic stem cells (hESCs) and induced pluripotent stem cells proliferate rapidly and divide symmetrically producing equivalent progeny cells. In contrast, lineage committed cells acquire an extended symmetrical cell cycle. Self-renewal of tissue-specific stem cells is sustained by asymmetric cell division where one progeny cell remains a progenitor while the partner progeny cell exits the cell cycle and differentiates. There are three principal contexts for considering the operation and regulation of the pluripotent cell cycle: temporal, regulatory, and structural. The primary temporal context that the pluripotent self-renewal cell cycle of hESCs is a short G1 period without reducing periods of time allocated to S phase, G2, and mitosis. The rules that govern proliferation in hESCs remain to be comprehensively established. However, several lines of evidence suggest a key role for the naïve transcriptome of hESCs, which is competent to stringently regulate the embryonic stem cell (ESC) cell cycle. This supports the requirements of pluripotent cells to self-propagate while suppressing expression of genes that confer lineage commitment and/or tissue specificity. However, for the first time, we consider unique dimensions to the architectural organization and assembly of regulatory machinery for gene expression in nuclear microenviornments that define parameters of pluripotency. From both fundamental biological and clinical perspectives, understanding control of the abbreviated ESC cycle can provide options to coordinate control of proliferation versus differentiation. Wound healing, tissue engineering, and cell-based therapy to mitigate developmental aberrations illustrate applications that benefit from knowledge of the biology of the pluripotent cell cycle.", "title": "The abbreviated pluripotent cell cycle." }, { "docid": "13497630", "text": "Importance Despite lack of evidence of their utility, biomarkers of ovarian reserve are being promoted as potential markers of reproductive potential. Objective To determine the associations between biomarkers of ovarian reserve and reproductive potential among women of late reproductive age. Design, Setting, and Participants Prospective time-to-pregnancy cohort study (2008 to date of last follow-up in March 2016) of women (N = 981) aged 30 to 44 years without a history of infertility who had been trying to conceive for 3 months or less, recruited from the community in the Raleigh-Durham, North Carolina, area. Exposures Early-follicular-phase serum level of antimüllerian hormone (AMH), follicle-stimulating hormone (FSH), and inhibin B and urinary level of FSH. Main Outcomes and Measures The primary outcomes were the cumulative probability of conception by 6 and 12 cycles of attempt and relative fecundability (probability of conception in a given menstrual cycle). Conception was defined as a positive pregnancy test result. Results A total of 750 women (mean age, 33.3 [SD, 3.2] years; 77% white; 36% overweight or obese) provided a blood and urine sample and were included in the analysis. After adjusting for age, body mass index, race, current smoking status, and recent hormonal contraceptive use, women with low AMH values (<0.7 ng/mL [n = 84]) did not have a significantly different predicted probability of conceiving by 6 cycles of attempt (65%; 95% CI, 50%-75%) compared with women (n = 579) with normal values (62%; 95% CI, 57%-66%) or by 12 cycles of attempt (84% [95% CI, 70%-91%] vs 75% [95% CI, 70%-79%], respectively). Women with high serum FSH values (>10 mIU/mL [n = 83]) did not have a significantly different predicted probability of conceiving after 6 cycles of attempt (63%; 95% CI, 50%-73%) compared with women (n = 654) with normal values (62%; 95% CI, 57%-66%) or after 12 cycles of attempt (82% [95% CI, 70%-89%] vs 75% [95% CI, 70%-78%], respectively). Women with high urinary FSH values (>11.5 mIU/mg creatinine [n = 69]) did not have a significantly different predicted probability of conceiving after 6 cycles of attempt (61%; 95% CI, 46%-74%) compared with women (n = 660) with normal values (62%; 95% CI, 58%-66%) or after 12 cycles of attempt (70% [95% CI, 54%-80%] vs 76% [95% CI, 72%-80%], respectively). Inhibin B levels (n = 737) were not associated with the probability of conceiving in a given cycle (hazard ratio per 1-pg/mL increase, 0.999; 95% CI, 0.997-1.001). Conclusions and Relevance Among women aged 30 to 44 years without a history of infertility who had been trying to conceive for 3 months or less, biomarkers indicating diminished ovarian reserve compared with normal ovarian reserve were not associated with reduced fertility. These findings do not support the use of urinary or blood follicle-stimulating hormone tests or antimüllerian hormone levels to assess natural fertility for women with these characteristics.", "title": "Association Between Biomarkers of Ovarian Reserve and Infertility Among Older Women of Reproductive Age" }, { "docid": "13179318", "text": "In traditional Kaplan-Meier or Cox regression analysis, usually a risk factor measured at baseline is related to mortality thereafter. During follow-up, however, things may change: either the effect of a fixed baseline risk factor may vary over time, resulting in a weakening or strengthening of associations over time, or the risk factor itself may vary over time. In this paper, short-term versus long-term effects (so-called time-dependent effects) of a fixed baseline risk factor are addressed. An example is presented showing that underweight is a strong risk factor for mortality in dialysis patients, especially in the short run. In contrast, overweight is a risk factor for mortality, which is stronger in the long run than in the short run. In addition, the analysis of how time-varying risk factors (so-called time-dependent risk factors) are related to mortality is demonstrated by paying attention to the pitfall of adjusting for sequelae. The proper analysis of effects over time should be driven by a clear research question. Both kinds of research questions, that is those of time-dependent effects as well those of time-dependent risk factors, can be analyzed with time-dependent Cox regression analysis. It will be shown that using time-dependent risk factors usually implies focusing on short-term effects only.", "title": "Survival analysis: time-dependent effects and time-varying risk factors." }, { "docid": "10189634", "text": "CENP-A chromatin forms the foundation for kinetochore assembly. Replication-independent incorporation of CENP-A at centromeres depends on its chaperone HJURP(Scm3), and Mis18 in vertebrates and fission yeast. The recruitment of Mis18 and HJURP(Scm3) to centromeres is cell cycle regulated. Vertebrate Mis18 associates with Mis18BP1(KNL2), which is critical for the recruitment of Mis18 and HJURP(Scm3). We identify two novel fission yeast Mis18-interacting proteins (Eic1 and Eic2), components of the Mis18 complex. Eic1 is essential to maintain Cnp1(CENP-A) at centromeres and is crucial for kinetochore integrity; Eic2 is dispensable. Eic1 also associates with Fta7(CENP-Q/Okp1), Cnl2(Nkp2) and Mal2(CENP-O/Mcm21), components of the constitutive CCAN/Mis6/Ctf19 complex. No Mis18BP1(KNL2) orthologue has been identified in fission yeast, consequently it remains unknown how the key Cnp1(CENP-A) loading factor Mis18 is recruited. Our findings suggest that Eic1 serves a function analogous to that of Mis18BP1(KNL2), thus representing the functional counterpart of Mis18BP1(KNL2) in fission yeast that connects with a module within the CCAN/Mis6/Ctf19 complex to allow the temporally regulated recruitment of the Mis18/Scm3(HJURP) Cnp1(CENP-A) loading factors. The novel interactions identified between CENP-A loading factors and the CCAN/Mis6/Ctf19 complex are likely to also contribute to CENP-A maintenance in other organisms.", "title": "Eic1 links Mis18 with the CCAN/Mis6/Ctf19 complex to promote CENP-A assembly" }, { "docid": "41710132", "text": "The tumor suppressor PML (promyelocytic leukemia protein) regulates cellular senescence and terminal differentiation, two processes that implicate a permanent exit from the cell cycle. Here, we show that the mechanism by which PML induces a permanent cell cycle exit and activates p53 and senescence involves a recruitment of E2F transcription factors bound to their promoters and the retinoblastoma (Rb) proteins to PML nuclear bodies enriched in heterochromatin proteins and protein phosphatase 1α. Blocking the functions of the Rb protein family or adding back E2Fs to PML-expressing cells can rescue their defects in E2F-dependent gene expression and cell proliferation, inhibiting the senescent phenotype. In benign prostatic hyperplasia, a neoplastic disease that displays features of senescence, PML was found to be up-regulated and forming nuclear bodies. In contrast, PML bodies were rarely visualized in prostate cancers. The newly defined PML/Rb/E2F pathway may help to distinguish benign tumors from cancers, and suggest E2F target genes as potential targets to induce senescence in human tumors.", "title": "Regulation of E2Fs and senescence by PML nuclear bodies." }, { "docid": "5145974", "text": "STUDY QUESTION In women undergoing IVF, are urinary bisphenol A (BPA) concentrations associated with ovarian response and early reproductive outcomes, including oocyte maturation and fertilization, Day 3 embryo quality and blastocyst formation? SUMMARY ANSWER Higher urinary BPA concentrations were found to be associated with decreased ovarian response, number of fertilized oocytes and decreased blastocyst formation. WHAT IS KNOWN ALREADY Experimental animal and in vitro studies have reported associations between BPA exposure and adverse reproductive outcomes. We previously reported an association between urinary BPA and decreased ovarian response [peak serum estradiol (E(2)) and oocyte count at the time of retrieval] in women undergoing IVF; however, there are limited human data on reproductive health outcomes, such as fertilization and embryo development. STUDY DESIGN, SIZE AND DURATION Prospective preconception cohort study. One hundred and seventy-four women aged 18-45 years and undergoing 237 IVF cycles were recruited at the Massachusetts General Hospital Fertility Center, Boston, MA, USA, between November 2004 and August 2010. These women were followed until they either had a live birth or discontinued treatment. Cryothaw and donor egg cycles were not included in the analysis. \n PARTICIPANTS/MATERIALS, SETTING AND METHODS Urinary BPA concentrations were measured by online solid-phase extraction-high-performance liquid chromatography-isotope dilution-tandem mass spectrometry. Mixed effect models, poisson regression and multivariate logistic regression models were used wherever appropriate to evaluate the association between cycle-specific urinary BPA concentrations and measures of ovarian response, oocyte maturation (metaphase II), fertilization, embryo quality and cleavage rate. We accounted for correlation among multiple IVF cycles in the same woman using generalized estimating equations. \n MAIN RESULTS AND THE ROLE OF CHANCE The geometric mean (SD) for urinary BPA concentrations was 1.50 (2.22) µg/l. After adjustment for age and other potential confounders (Day 3 serum FSH, smoking, BMI), there was a significant linear dose-response association between increased urinary BPA concentrations and decreased number of oocytes (overall and mature), decreased number of normally fertilized oocytes and decreased E(2) levels (mean decreases of 40, 253 and 471 pg/ml for urinary BPA quartiles 2, 3 and 4, when compared with the lowest quartile, respectively; P-value for trend = 0.001). The mean number of oocytes and normally fertilized oocytes decreased by 24 and 27%, respectively, for the highest versus the lowest quartile of urinary BPA (trend test P < 0.001 and 0.002, respectively). Women with urinary BPA above the lowest quartile had decreased blastocyst formation (trend test P-value = 0.08). LIMITATIONS AND REASONS FOR CAUTION Potential limitations include exposure misclassification due to the very short half-life of BPA and its high variability over time; uncertainty about the generalizability of the results to the general population of women conceiving naturally and limited sample. WIDER IMPLICATIONS OF THE FINDINGS The results from this extended study, using IVF as a model to study early reproductive health outcomes in humans, indicate a negative dose-response association between urinary BPA concentrations and serum peak E(2) and oocyte yield, confirming our previous findings. In addition, we found significantly decreased metaphase II oocyte count and number of normally fertilizing oocytes and a suggestive association between BPA urinary concentrations and decreased blastocyst formation, thus indicating that BPA may alter reproductive function in susceptible women undergoing IVF. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by grants ES009718 and ES000002 from the National Institute of Environmental Health Sciences and grant OH008578 from the National Institute for Occupational Safety and Health. None of the authors has actual or potential competing financial interests. DISCLAIMER The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.", "title": "Urinary bisphenol A concentrations and early reproductive health outcomes among women undergoing IVF." }, { "docid": "10846815", "text": "The actin cortex both facilitates and hinders the exocytosis of secretory granules. How cells consolidate these two opposing roles was not well understood. Here we show that antigen activation of mast cells induces oscillations in Ca(2+) and PtdIns(4,5)P(2) lipid levels that in turn drive cyclic recruitment of N-WASP and cortical actin level oscillations. Experimental and computational analysis argues that vesicle fusion correlates with the observed actin and Ca(2+) level oscillations. A vesicle secretion cycle starts with the capture of vesicles by actin when cortical F-actin levels are high, followed by vesicle passage through the cortex when F-actin levels are low, and vesicle fusion with the plasma membrane when Ca(2+) levels subsequently increase. Thus, cells employ oscillating levels of Ca(2+), PtdIns(4,5)P(2) and cortical F-actin to increase secretion efficiency, explaining how the actin cortex can function as a carrier as well as barrier for vesicle secretion.", "title": "Coordinated oscillations in cortical actin and Ca2+ correlate with cycles of vesicle secretion" }, { "docid": "2212067", "text": "Circadian cycles and cell cycles are two fundamental periodic processes with a period in the range of 1 day. Consequently, coupling between such cycles can lead to synchronization. Here, we estimated the mutual interactions between the two oscillators by time-lapse imaging of single mammalian NIH3T3 fibroblasts during several days. The analysis of thousands of circadian cycles in dividing cells clearly indicated that both oscillators tick in a 1:1 mode-locked state, with cell divisions occurring tightly 5 h before the peak in circadian Rev-Erbα-YFP reporter expression. In principle, such synchrony may be caused by either unidirectional or bidirectional coupling. While gating of cell division by the circadian cycle has been most studied, our data combined with stochastic modeling unambiguously show that the reverse coupling is predominant in NIH3T3 cells. Moreover, temperature, genetic, and pharmacological perturbations showed that the two interacting cellular oscillators adopt a synchronized state that is highly robust over a wide range of parameters. These findings have implications for circadian function in proliferative tissues, including epidermis, immune cells, and cancer.", "title": "Robust synchronization of coupled circadian and cell cycle oscillators in single mammalian cells" }, { "docid": "641459", "text": "BACKGROUND Asthma prevalence appears to be increasing in the general population. We sought to determine whether asthma prevalence has also increased in highly competitive athletes. \n OBJECTIVE Our aim was to determine how many United States Olympic athletes who were chosen to participate in the 1996 Summer Olympic Games had a past history of asthma or symptoms that suggested asthma or took asthma medications. \n METHODS We analyzed responses to questions that asked about allergic and respiratory diseases on the United States Olympic Committee (USOC) Medical History Questionnaire that was completed by all athletes who were chosen to represent the US at the 1996 Summer Olympic Games in Atlanta. \n RESULTS Of the 699 athletes who completed the questionnaire, 107 (15.3%) had a previous diagnosis of asthma, and 97 (13.9%) recorded use of an asthma medication at some time in the past. One hundred seventeen (16.7%) reported use of an asthma medication, a diagnosis of asthma, or both (which was our basis for the diagnosis of asthma). Seventy-three (10. 4%) of the athletes were currently taking an asthma medication at the time that they were processed in Atlanta or noted that they took asthma medications on a permanent or semipermanent basis and were considered to have active asthma. Athletes who participated in cycling and mountain biking had the highest prevalence of having been told that they had asthma or had taken an asthma medication in the past (50%). Frequency of active asthma varied from 45% of cyclists and emountain bikers to none of the divers and weight lifters. Only about 11% of the athletes who participated in the 1984 Summer Olympic Games were reported to have had exercise-induced asthma on the basis of other criteria that may have been less restrictive. On the basis of these less restrictive criteria, more than 20% of the athletes who participated in the 1996 Olympic Games might have been considered to have had asthma. \n CONCLUSIONS Asthma appeared to have been more prevalent in athletes who participated in the 1996 Summer Games than in the general population or in those who participated in the 1984 Summer Games. This study also suggests that asthma may influence the sport that an athlete chooses.", "title": "Asthma in United States Olympic athletes who participated in the 1996 Summer Games." }, { "docid": "25670099", "text": "Using differential interference contrast optics, combined with cinematography, we have studied the morphological changes that the living, syncytial embryo undergoes from stage 10 through 14 of Drosophila embryogenesis, that is just prior to and during formation of the cellular blastoderm. We have supplemented these studies with data collected from fixed, stained, whole embryos. The following information has been obtained. The average duration of nuclear cycles 10, 11, 12 and 13 is about 9, 10, 12 and 21 min, respectively (25 degrees C). In these four cycles, the duration of that portion of the mitotic period that lacks a discrete nuclear envelope is 3, 3, 3 and 5 min, respectively. The length of nuclear cycle 14 varies in a position-specific manner throughout the embryo, the shortest cycles being of 65 min duration. During nuclear cycles 10 through 13, it is commonly observed in living embryos that the syncytial blastoderm nuclei enter (and leave) mitosis in one of two waves that originate nearly simultaneously from the opposite anterior and posterior poles of the embryo, and terminate in its midregion. From our preparations of quick-frozen embryos, we estimate that these mitotic waves take on average about half a minute to travel over the embryonic surface from pole to equator. The yolk nuclei, which remain in the core of the embryo when the rest of the nuclei migrate to the periphery, divide in synchrony with the migrating nuclei at nuclear cycles 8 and 9, and just after the now peripherally located nuclei at nuclear cycle 10. After cycle 10, these yolk nuclei cease dividing and become polyploid. The syncytial embryo has at least three distinct levels of cytoskeletal organization: structured domains of cytoplasm are organized around each blastoderm nucleus; radially directed tracks orient colchicine-sensitive saltatory transport throughout the peripheral cytoplasm; and a long-range organization of the core of the embryo makes possible coherent movements of the large inner yolk mass in concert with each nuclear cycle. This highly organized cytoplasm may be involved in providing positional information for the important process of nuclear determination that is known to occur during these stages.", "title": "Studies of nuclear and cytoplasmic behaviour during the five mitotic cycles that precede gastrulation in Drosophila embryogenesis." }, { "docid": "21557055", "text": "The tumor suppressor protein, p53, plays a critical role in mediating cellular response to stress signals by regulating genes involved in cell cycle arrest and apoptosis. p53 is believed to be inactive for DNA binding unless its C terminus is modified or structurally altered. We show that unmodified p53 actively binds to two sites at -1.4 and -2.3 kb within the chromatin-assembled p21 promoter and requires the C terminus and the histone acetyltransferase, p300, for transcription. Acetylation of the C terminus by p300 is not necessary for binding or promoter activation. Instead, p300 acetylates p53-bound nucleosomes in the p21 promoter with spreading to the TATA box. Thus, p53 is an active DNA and chromatin binding protein that may selectively regulate its target genes by recruitment of specific cofactors to structurally distinct binding sites.", "title": "Transcriptional regulation by p53 through intrinsic DNA/chromatin binding and site-directed cofactor recruitment." }, { "docid": "18333304", "text": "MOTIVATION Circadian oscillations have been observed in animals, plants, fungi and cyanobacteria and play a fundamental role in coordinating the homeostasis and behavior of biological systems. Genetically encoded molecular clocks found in nearly every cell, based on negative transcription/translation feedback loops and involving only a dozen genes, play a central role in maintaining these oscillations. However, high-throughput gene expression experiments reveal that in a typical tissue, a much larger fraction ([Formula: see text]) of all transcripts oscillate with the day-night cycle and the oscillating species vary with tissue type suggesting that perhaps a much larger fraction of all transcripts, and perhaps also other molecular species, may bear the potential for circadian oscillations. \n RESULTS To better quantify the pervasiveness and plasticity of circadian oscillations, we conduct the first large-scale analysis aggregating the results of 18 circadian transcriptomic studies and 10 circadian metabolomic studies conducted in mice using different tissues and under different conditions. We find that over half of protein coding genes in the cell can produce transcripts that are circadian in at least one set of conditions and similarly for measured metabolites. Genetic or environmental perturbations can disrupt existing oscillations by changing their amplitudes and phases, suppressing them or giving rise to novel circadian oscillations. The oscillating species and their oscillations provide a characteristic signature of the physiological state of the corresponding cell/tissue. Molecular networks comprise many oscillator loops that have been sculpted by evolution over two trillion day-night cycles to have intrinsic circadian frequency. These oscillating loops are coupled by shared nodes in a large network of coupled circadian oscillators where the clock genes form a major hub. Cells can program and re-program their circadian repertoire through epigenetic and other mechanisms. AVAILABILITY AND IMPLEMENTATION High-resolution and tissue/condition specific circadian data and networks available at http://circadiomics.igb.uci.edu. CONTACT pfbaldi@ics.uci.edu SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.", "title": "The pervasiveness and plasticity of circadian oscillations: the coupled circadian-oscillators framework." } ]

[ { "docid": "5912283", "text": "CONTEXT Insomnia is a common condition in older adults and is associated with a number of adverse medical, social, and psychological consequences. Previous research has suggested beneficial outcomes of both psychological and pharmacological treatments, but blinded placebo-controlled trials comparing the effects of these treatments are lacking. \n OBJECTIVE To examine short- and long-term clinical efficacy of cognitive behavioral therapy (CBT) and pharmacological treatment in older adults experiencing chronic primary insomnia. \n DESIGN, SETTING, AND PARTICIPANTS A randomized, double-blinded, placebo-controlled trial of 46 adults (mean age, 60.8 y; 22 women) with chronic primary insomnia conducted between January 2004 and December 2005 in a single Norwegian university-based outpatient clinic for adults and elderly patients. \n INTERVENTION CBT (sleep hygiene, sleep restriction, stimulus control, cognitive therapy, and relaxation; n = 18), sleep medication (7.5-mg zopiclone each night; n = 16), or placebo medication (n = 12). All treatment duration was 6 weeks, and the 2 active treatments were followed up at 6 months. \n MAIN OUTCOME MEASURES Ambulant clinical polysomnographic data and sleep diaries were used to determine total wake time, total sleep time, sleep efficiency, and slow-wave sleep (only assessed using polysomnography) on all 3 assessment points. \n RESULTS CBT resulted in improved short- and long-term outcomes compared with zopiclone on 3 out of 4 outcome measures. For most outcomes, zopiclone did not differ from placebo. Participants receiving CBT improved their sleep efficiency from 81.4% at pretreatment to 90.1% at 6-month follow-up compared with a decrease from 82.3% to 81.9% in the zopiclone group. Participants in the CBT group spent much more time in slow-wave sleep (stages 3 and 4) compared with those in other groups, and spent less time awake during the night. Total sleep time was similar in all 3 groups; at 6 months, patients receiving CBT had better sleep efficiency using polysomnography than those taking zopiclone. \n CONCLUSION These results suggest that interventions based on CBT are superior to zopiclone treatment both in short- and long-term management of insomnia in older adults. \n TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00295386.", "title": "Cognitive behavioral therapy vs zopiclone for treatment of chronic primary insomnia in older adults: a randomized controlled trial." }, { "docid": "31554917", "text": "Circadian rhythm sleep disorders are characterized by complaints of insomnia and excessive sleepiness that are primarily due to alterations in the internal circadian timing system or a misalignment between the timing of sleep and the 24-h social and physical environment. In addition to physiological and environmental factors, maladaptive behaviors often play an important role in the development of many of the circadian rhythm sleep disorders. This review will focus on the clinical approach to the diagnosis and management of the various circadian rhythm sleep disorders, including delayed sleep phase disorder, advanced sleep phase disorder, non-entrained type, irregular sleep-wake rhythm, shift work sleep disorder and jet lag disorder. Diagnostic tools such as sleep diaries and wrist activity monitoring are often useful in confirming the diagnosis. Because behavioral and environmental factors often are involved in the development of these conditions, a multimodal approach is usually necessary. Interventions include sleep hygiene education, timed exposure to bright light as well as avoidance of bright light at the wrong time of the day and pharmacologic approaches, such as melatonin. However, it should be noted that the use of melatonin is not an FDA-approved indication for the treatment of circadian rhythm sleep disorders.", "title": "A clinical approach to circadian rhythm sleep disorders." } ]

[ { "docid": "24865781", "text": "Forty-one recurrent tension headache sufferers were randomly assigned to either cognitive-behavioral therapy (administered in a primarily home-based treatment protocol) or to amitriptyline therapy (with dosage individualized at 25, 50, or 75 mg/day). Cognitive-behavioral therapy and amitriptyline each yielded clinically significant improvements in headache activity, both when improvement was assessed with patient daily recordings (56% and 27% reduction in headache index, respectively), and when improvement was assessed with neurologist ratings of clinical improvement (94% and 69% of patients rated at least moderately improved, respectively). In instances where differences in treatment effectiveness were observed (headache index, somatic complaints, perceptions of control of headache activity), cognitive-behavioral therapy yielded somewhat more positive outcomes than did amitriptyline. Neither treatment, however, eliminated headache problems.", "title": "A comparison of pharmacological (amitriptyline HCL) and nonpharmacological (cognitive-behavioral) therapies for chronic tension headaches." }, { "docid": "24346598", "text": "PURPOSE To assess the efficacy, dose stability, safety, and abuse potential of long-term, nightly benzodiazepine treatment of chronic disorders of disrupted nocturnal sleep. \n PATIENTS AND METHODS During a 12-year period, one author evaluated and treated 170 adult referrals for > or = 6 months with nightly benzodiazepine therapy for longstanding, sleep-disruptive disorders: injurious sleepwalking and sleep terrors (69); rapid eye movement sleep behavior disorder (52); chronic, severe insomnia (25); and restless legs syndrome/periodic limb movement disorder (24). \n RESULTS Complete/substantial control of the sleep disorders was achieved by 146 patients (86%); 8% had adverse effects requiring medication changes; 2% had relapses of alcohol or chemical abuse requiring hospitalization; another 2% at times misused their medications. A total of 136 patients received clonazepam nightly for a mean 3.5 (+/- 2.4) years, with no significant difference in inital versus final mean dose: 0.77 mg (+/- 0.46) versus 1.10 mg (+/- 0.96). Similar results were obtained with chronic alprazolam treatment and with other benzodiazepine treatments. \n CONCLUSION Long-term, nightly benzodiazepine treatment of injurious parasomnias and other disorders of disrupted nocturnal sleep resulted in sustained efficacy in most cases, with low risk of dosage tolerance, adverse effects, or abuse. Data from this study on the treatment of chronic, severe insomnia (a small subset of all insomnia) are not generalizable to the typical insomnia patient.", "title": "Long-term, nightly benzodiazepine treatment of injurious parasomnias and other disorders of disrupted nocturnal sleep in 170 adults." }, { "docid": "10749308", "text": "Placebo-controlled trials are used extensively in the development of new pharmaceuticals. They are sometimes challenged as unethical in settings in which patients could be treated with an existing therapy (1-7). The issues of when placebo controls are ethically acceptable and when they are scientifically necessary are important and worthy of discussion. The Ethics of Placebo Controls The Declaration of Helsinki The Declaration of Helsinki (8) is an international document that describes ethical principles for clinical investigation. Those who contend that placebo controls are unethical whenever known effective therapy exists for a condition usually cite the following sentence in the Declaration as support for that position: In any medical study, every patientincluding those of a control group, if anyshould be assured of the best proven diagnostic and therapeutic method. We believe that an interpretation of this sentence as barring placebo controls whenever an effective treatment exists is untenable. First, the requirement that all patients receive the best proven diagnostic and therapeutic method would bar not only placebo-controlled trials but also active-control and historically controlled trials. When effective treatment exists, the patient receiving the investigational treatment instead of the established therapy is clearly not getting the best proven treatment. Second, it does not seem reasonable to consider as equivalent all failures to use known effective therapy. Historically, concerns about placebo use have usually arisen in the context of serious illness. There is universal agreement that use of placebo or otherwise untreated controls is almost always unethical when therapy shown to improve survival or decrease serious morbidity is available. But in cases in which the treatment does not affect the patient's long-term health, an ethical imperative to use existing therapy is not plausible. Can it be, for example, that because topical minoxidil or oral finasteride can grow hair, a placebo-controlled trial of a new remedy for baldness is unethical? Is it really unethical to use placebos in short-term studies of drugs for allergic rhinitis, insomnia, anxiety, dermatoses, heartburn, or headaches in fully informed patients? We do not believe that there is a reasonable basis for arguing that such studies and many other placebo-controlled studies of symptom relief are unethical and that an informed patient cannot properly be asked to participate in them. Third, there is good reason to doubt that the cited phrase was intended to discourage placebo-controlled trials. The phrase under discussion was not part of the original 1964 Declaration but was added in 1975 to reinforce the idea that the physicianpatient relationship must be respected just as it would be in a purely therapeutic situation not involving research objectives (8). In the explanation accompanying the 1975 change, the issue of placebo-controlled trials was not even mentioned (9). The American Medical Association (10), the World Health Organization (11), and the Council for International Organizations of Medical Sciences (12) have rejected the position that the Declaration uniformly bars placebo-controlled trials when proven therapy is available. Informed Consent in Placebo-Controlled Trials Patients asked to participate in a placebo-controlled trial must be informed of the existence of any effective therapy, must be able to explore the consequences of deferring such therapy with the investigator, and must provide fully informed consent. Concern about whether consent to participate in trials is as informed as we would like to believe is valid, but these concerns apply as much to the patient's decision to forgo known effective treatment and risk exposure to a potentially ineffective or even harmful new agent in an active-control trial as to a decision to accept possible persistence of symptoms in a placebo-controlled trial. Thus, this problem is not unique to placebo-controlled trials. For the above reasons, we conclude that placebo-controlled trials may be ethically conducted even when effective therapy exists, as long as patients will not be harmed by participation and are fully informed about their alternatives. Although in many cases application of this standard will be fairly straightforward, in others it will not, and there may be debate about the consequences of deferring treatment (13). Assessment of Effectiveness with Active-Control Trials Clinical trials that, because of deficiencies in study design or conduct, are unlikely to provide scientifically valid and clinically meaningful results raise their own ethical concerns (12, 14). The remainder of this paper will address the inability of commonly proposed alternatives to placebo-controlled trials to evaluate the effectiveness of new treatments in many medical settings. Active-Control Equivalence Trials (Noninferiority Trials) The ability to conduct a placebo-controlled trial ethically in a given situation does not necessarily mean that placebo-controlled trials should be carried out when effective therapy exists. Patients and physicians might still prefer a trial in which every participant is given an active treatment. What remains to be examined is why placebo-controlled trials (or, more generally, trials intended to show an advantage of one treatment over another) are frequently needed to demonstrate the effectiveness of new treatments and often cannot be replaced by active-control trials showing that a new drug is equivalent or noninferior to a known effective agent. The limitations of active-control equivalence trials (ACETs) that are intended to show the effectiveness of a new drug have long been recognized and are well described (15-33) but are perhaps not as widely appreciated as they should be. A recent proposed international guideline on choice of control group addresses this issue in detail (33). The Fundamental Problem: Need for Assay Sensitivity There are two distinct ways to show that a new therapy is effective. One can show that the new therapy is superior to a control treatment, or one can show that the new therapy is equivalent to or not worse by some defined amount than a known effective treatment. Each method can be valid, but each requires entirely different inferential approaches. A well-designed study that shows superiority of a treatment to a control (placebo or active therapy) provides strong evidence of the effectiveness of the new treatment, limited only by the statistical uncertainty of the result. No information external to the trial is needed to support the conclusion of effectiveness. In contrast, a study that successfully shows equivalencethat is, little difference between a new drug and known active treatmentdoes not by itself demonstrate that the new treatment is effective. Equivalence could mean that the treatments were both effective in the study, but it could also mean that both treatments were ineffective in the study. To conclude from an ACET that a new treatment is effective on the basis of its similarity to the active control, one must make the critical (and untestable within the study) assumption that the active control had an effect in that particular study. In other words, one must assume that if a placebo group had been included, the placebo would have been inferior to the active control (15-33). Support for this assumption must come from sources external to the trial. Although it might appear reasonable to expect a known active agent to be superior to placebo in any given appropriately designed trial, experience has shown that this is not the case for many types of drugs. The ability of a study to distinguish between active and inactive treatments is termed assay sensitivity. If assay sensitivity cannot be assumed, then even if the new and standard treatments appear virtually identical and the confidence interval for their comparison is exquisitely narrow, the study cannot demonstrate effectiveness of the new drug. (Note that in practice, ACETs are not designed simply to show lack of a statistically significant difference between treatments. Rather, such trials are designed to show noninferioritythat the new treatment is not inferior to the control by more than a specified margin. This approach is described in the Appendix.) The best evidence that an active drug would have an effect superior to that of placebo in a given study would be a series of trials of similar design in which the active drug has reliably outperformed placebo. The ACET thus requires information external to the trial (the information about past placebo-controlled studies of the active control) to interpret the results. In this respect, an ACET is similar to a historically controlled trial. In some settings, such as highly responsive cancers, most infectious diseases, and some cardiovascular conditions, such external information is available and ACETs can and do provide a valid and reliable basis for evaluating new treatments. In many cases, however, the historically based assumption of assay sensitivity cannot be made; for many types of effective drugs, studies of apparently adequate size and design do not regularly distinguish drugs from placebo (16-18, 25, 34). More than 20 years ago, Lasagna (19) described this difficulty particularly well (reflecting long recognition of the problem among analgesiologists): a comparison between new drug and standard is convincing only when the new remedy is superior to standard treatment. If it is inferior, or even indistinguishable from a standard remedy, the results are not readily interpretable. In the absence of placebo controls, one does not know if the inferior new medicine has any efficacy at all, and equivalent performance may reflect simply a patient population that cannot distinguish between two active treatments that differ considerably from each other, or between active drug and placebo. Certain clinical conditions, such as seri", "title": "Placebo-Controlled Trials and Active-Control Trials in the Evaluation of New Treatments. Part 1: Ethical and Scientific Issues" }, { "docid": "7627167", "text": "BACKGROUND The objective of this study was to evaluate the effectiveness of a brief, 4-session cognitive behavioral, group psychotherapy for binge eating among bariatric surgery candidates at an academic medical center. Binge eating behaviors have been linked to poorer outcomes among bariatric surgery patients, and binge eating disorder have be considered a contraindication in surgery programs, some of which have mandated preoperative binge eating treatment. However, no previous studies have examined whether a preoperative binge eating intervention could successfully reduce binge eating behaviors among severely obese bariatric surgery candidates. \n METHODS A total of 243 bariatric surgery candidates completed a brief cognitive behavioral group treatment for binge eating behaviors and were administered the Binge Eating Scale and reported the number of weekly binge eating episodes at the initial psychological evaluation and again after the group sessions. The study used a pre-post intervention design. \n RESULTS The results suggested significant reductions in both binge eating behaviors and cognitions and binge eating episodes after the group intervention. The intervention's effectiveness did not differ according to gender or ethnicity (black versus white). \n CONCLUSION A brief cognitive behavioral intervention can reduce binge eating behaviors among bariatric surgery candidates. Given the potential influence of binge eating on outcomes, bariatric surgery programs could benefit by treating binge eating before surgery.", "title": "Brief, four-session group CBT reduces binge eating behaviors among bariatric surgery candidates." }, { "docid": "24159217", "text": "CONTEXT No randomized controlled studies have been conducted to date on the effectiveness of psychological interventions for children with symptoms of posttraumatic stress disorder (PTSD) that has resulted from personally witnessing or being personally exposed to violence. \n OBJECTIVE To evaluate the effectiveness of a collaboratively designed school-based intervention for reducing children's symptoms of PTSD and depression that has resulted from exposure to violence. \n DESIGN A randomized controlled trial conducted during the 2001-2002 academic year. \n SETTING AND PARTICIPANTS Sixth-grade students at 2 large middle schools in Los Angeles who reported exposure to violence and had clinical levels of symptoms of PTSD. \n INTERVENTION Students were randomly assigned to a 10-session standardized cognitive-behavioral therapy (the Cognitive-Behavioral Intervention for Trauma in Schools) early intervention group (n = 61) or to a wait-list delayed intervention comparison group (n = 65) conducted by trained school mental health clinicians. \n MAIN OUTCOME MEASURES Students were assessed before the intervention and 3 months after the intervention on measures assessing child-reported symptoms of PTSD (Child PTSD Symptom Scale; range, 0-51 points) and depression (Child Depression Inventory; range, 0-52 points), parent-reported psychosocial dysfunction (Pediatric Symptom Checklist; range, 0-70 points), and teacher-reported classroom problems using the Teacher-Child Rating Scale (acting out, shyness/anxiousness, and learning problems; range of subscales, 6-30 points). \n RESULTS Compared with the wait-list delayed intervention group (no intervention), after 3 months of intervention students who were randomly assigned to the early intervention group had significantly lower scores on symptoms of PTSD (8.9 vs 15.5, adjusted mean difference, - 7.0; 95% confidence interval [CI], - 10.8 to - 3.2), depression (9.4 vs 12.7, adjusted mean difference, - 3.4; 95% CI, - 6.5 to - 0.4), and psychosocial dysfunction (12.5 vs 16.5, adjusted mean difference, - 6.4; 95% CI, -10.4 to -2.3). Adjusted mean differences between the 2 groups at 3 months did not show significant differences for teacher-reported classroom problems in acting out (-1.0; 95% CI, -2.5 to 0.5), shyness/anxiousness (0.1; 95% CI, -1.5 to 1.7), and learning (-1.1, 95% CI, -2.9 to 0.8). At 6 months, after both groups had received the intervention, the differences between the 2 groups were not significantly different for symptoms of PTSD and depression; showed similar ratings for psychosocial function; and teachers did not report significant differences in classroom behaviors. \n CONCLUSION A standardized 10-session cognitive-behavioral group intervention can significantly decrease symptoms of PTSD and depression in students who are exposed to violence and can be effectively delivered on school campuses by trained school-based mental health clinicians.", "title": "A mental health intervention for schoolchildren exposed to violence: a randomized controlled trial." }, { "docid": "31884697", "text": "Background Spinocerebellar ataxia type 1 (SCA1) is a dominantly inherited neurodegenerative disorder characterized by progressive motor and cognitive dysfunction. Caused by an expanded polyglutamine tract in ataxin 1 (ATXN1), SCA1 pathogenesis involves a multifactorial process that likely begins with misfolding of ATXN1, which has functional consequences on its interactions, leading to transcriptional dysregulation. Because lithium has been shown to exert neuroprotective effects in a variety of conditions, possibly by affecting gene expression, we tested the efficacy of lithium treatment in a knock-in mouse model of SCA1 (Sca1154Q/2Q mice) that replicates many features of the human disease. Methods and Findings Sca1154Q/2Q mice and their wild-type littermates were fed either regular chow or chow that contained 0.2% lithium carbonate. Dietary lithium carbonate supplementation resulted in improvement of motor coordination, learning, and memory in Sca1154Q/2Q mice. Importantly, motor improvement was seen when treatment was initiated both presymptomatically and after symptom onset. Neuropathologically, lithium treatment attenuated the reduction of dendritic branching in mutant hippocampal pyramidal neurons. We also report that lithium treatment restored the levels of isoprenylcysteine carboxyl methyltransferase (Icmt; alternatively, Pccmt), down-regulation of which is an early marker of mutant ATXN1 toxicity. Conclusions The effect of lithium on a marker altered early in the course of SCA1 pathogenesis, coupled with its positive effect on multiple behavioral measures and hippocampal neuropathology in an authentic disease model, make it an excellent candidate treatment for human SCA1 patients.", "title": "Lithium Therapy Improves Neurological Function and Hippocampal Dendritic Arborization in a Spinocerebellar Ataxia Type 1 Mouse Model" }, { "docid": "19571273", "text": "Brain-derived neurotrophic factor (BDNF) regulates synaptic activity and behavioral flexibility, and reduction of BDNF strongly predicts psychiatric disorders and cognitive dysfunction. Restoration of BDNF-dependent activity could alleviate these impairments, but BDNF has limited clinical utility due to its pharmacokinetics. Here we demonstrate that activation of a primary BDNF target, the tropomyosin-related kinase B (TrkB) receptor, enhances the amplitude and prolongs the decay kinetics of N-methyl-d-aspartate receptor (NMDAR) currents in male rat infralimbic prefrontal pyramidal neurons. Moreover, these effects were prevented and reversed by blockade of NMDARs containing the GluN2B subunit. Our results show that this signaling cascade bidirectionally regulates extinction of a cocaine-induced conditioned place preference (CPP), a task that requires behavioral flexibility. Blockade of infralimbic TrkB receptors or GluN2B-containing NMDARs disrupted consolidation of extinction of the CPP. In contrast, extinction was strengthened by potentiation of TrkB receptor activity with infralimbic infusions of BDNF or systemic injections of 7,8 dihydroxyflavone (7,8DHF), the newly synthesized TrkB receptor agonist. The 7,8DHF-induced enhancement of extinction was prevented by infralimbic infusions of a GluN2B-specific receptor antagonist, demonstrating that TrkB receptor activation enhances extinction of cocaine-CPP via GluN2B-containing NMDARs. Together, infralimbic TrkB receptor activation strengthens GluN2B-containing NMDAR currents to support extinction learning. TrkB receptor agonists would therefore be useful as pharmacological adjuncts for extinction-based therapies for treatment of psychiatric disorders associated with reduced BDNF activity.", "title": "Infralimbic BDNF/TrkB enhancement of GluN2B currents facilitates extinction of a cocaine-conditioned place preference." }, { "docid": "6191684", "text": "CONTEXT Chronic tension-type headaches are characterized by near-daily headaches and often are difficult to manage in primary practice. Behavioral and pharmacological therapies each appear modestly effective, but data are lacking on their separate and combined effects. \n OBJECTIVE To evaluate the clinical efficacy of behavioral and pharmacological therapies, singly and combined, for chronic tension-type headaches. \n DESIGN AND SETTING Randomized placebo-controlled trial conducted from August 1995 to January 1998 at 2 outpatient sites in Ohio. \n PARTICIPANTS Two hundred three adults (mean age, 37 years; 76% women) with diagnosis of chronic tension-type headaches (mean, 26 headache d/mo). \n INTERVENTIONS Participants were randomly assigned to receive tricyclic antidepressant (amitriptyline hydrochloride, up to 100 mg/d, or nortriptyline hydrochloride, up to 75 mg/d) medication (n = 53), placebo (n = 48), stress management (eg, relaxation, cognitive coping) therapy (3 sessions and 2 telephone contacts) plus placebo (n = 49), or stress management therapy plus antidepressant medication (n = 53). \n MAIN OUTCOME MEASURES Monthly headache index scores calculated as the mean of pain ratings (0-10 scale) recorded by participants in a daily diary 4 times per day; number of days per month with at least moderate pain (pain rating >/=5), analgesic medication use, and Headache Disability Inventory scores, compared by intervention group. \n RESULTS Tricyclic antidepressant medication and stress management therapy each produced larger reductions in headache activity, analgesic medication use, and headache-related disability than placebo, but antidepressant medication yielded more rapid improvements in headache activity. Combined therapy was more likely to produce clinically significant (>/=50%) reductions in headache index scores (64% of participants) than antidepressant medication (38% of participants; P =.006), stress management therapy (35%; P =.003), or placebo (29%; P =.001). On other measures the combined therapy and its 2 component therapies produced similar outcomes. \n CONCLUSIONS Our results indicate that antidepressant medication and stress management therapy are each modestly effective in treating chronic tension-type headaches. Combined therapy may improve outcome relative to monotherapy.", "title": "Management of chronic tension-type headache with tricyclic antidepressant medication, stress management therapy, and their combination: a randomized controlled trial." }, { "docid": "22467585", "text": "Background: The loss of a child during pregnancy causes significant psychological distress for many women and their partners, and may lead to long-lasting psychiatric disorders. Internet-based interventions using exposure techniques and cognitive restructuring have proved effective for posttraumatic stress disorder (PTSD) and prolonged grief. This study compared the effects of an Internet-based intervention for parents after prenatal loss with a waiting list condition (WLC). Methods: The Impact of Event Scale - Revised assessed symptoms of PTSD; the Inventory of Complicated Grief and the Brief Symptom Inventory assessed depression, anxiety, and general mental health. The 228 participants (92% female) were randomly allocated to a treatment group (TG; n = 115) or a WLC group (n = 113). The TG received a 5-week cognitive behavioral intervention including (1) self-confrontation, (2) cognitive restructuring, and (3) social sharing. Results: The TG showed significantly reduced symptoms of posttraumatic stress, prolonged grief, depression, and anxiety relative to the WLC control group. Intention-to-treat analysis revealed treatment effects of between d = 0.84 and d = 1.02 for posttraumatic stress and prolonged grief from pre- to posttreatment time points. Further significant improvement in all symptoms of PTSD and prolonged grief was found from the posttreatment evaluation to the 12-month follow-up. The attrition rate of 14% was relatively low. Conclusions: The Internet-based intervention proved to be a feasible and cost-effective treatment, reducing symptoms of posttraumatic stress, grief, depression, anxiety, and general mental health after pregnancy loss. Low-threshold e-health interventions should be further evaluated and implemented routinely to improve psychological support after pregnancy loss.", "title": "Brief Internet-Based Intervention Reduces Posttraumatic Stress and Prolonged Grief in Parents after the Loss of a Child during Pregnancy: A Randomized Controlled Trial" }, { "docid": "4587978", "text": "Patterns of daily human activity are controlled by an intrinsic circadian clock that promotes ∼24 hr rhythms in many behavioral and physiological processes. This system is altered in delayed sleep phase disorder (DSPD), a common form of insomnia in which sleep episodes are shifted to later times misaligned with the societal norm. Here, we report a hereditary form of DSPD associated with a dominant coding variation in the core circadian clock gene CRY1, which creates a transcriptional inhibitor with enhanced affinity for circadian activator proteins Clock and Bmal1. This gain-of-function CRY1 variant causes reduced expression of key transcriptional targets and lengthens the period of circadian molecular rhythms, providing a mechanistic link to DSPD symptoms. The allele has a frequency of up to 0.6%, and reverse phenotyping of unrelated families corroborates late and/or fragmented sleep patterns in carriers, suggesting that it affects sleep behavior in a sizeable portion of the human population.", "title": "Mutation of the Human Circadian Clock Gene CRY1 in Familial Delayed Sleep Phase Disorder" }, { "docid": "12672066", "text": "IMPORTANCE In 2011, the Centers for Medicare & Medicaid Services (CMS) approved intensive behavioral weight loss counseling for approximately 14 face-to-face, 10- to 15-minute sessions over 6 months for obese beneficiaries in primary care settings, when delivered by physicians and other CMS-defined primary care practitioners. \n OBJECTIVE To conduct a systematic review of behavioral counseling for overweight and obese patients recruited from primary care, as delivered by primary care practitioners working alone or with trained interventionists (eg, medical assistants, registered dietitians), or by trained interventionists working independently. EVIDENCE REVIEW We searched PubMed, CINAHL, and EMBASE for randomized controlled trials published between January 1980 and June 2014 that recruited overweight and obese patients from primary care; provided behavioral counseling (ie, diet, exercise, and behavioral therapy) for at least 3 months, with at least 6 months of postrandomization follow-up; included at least 15 participants per treatment group and objectively measured weights; and had a comparator, an intention-to-treat analysis, and attrition of less than 30% at 1 year or less than 40% at longer follow-up. \n FINDINGS Review of 3304 abstracts yielded 12 trials, involving 3893 participants, that met inclusion-exclusion criteria and prespecified quality ratings. No studies were found in which primary care practitioners delivered counseling that followed the CMS guidelines. Mean 6-month weight changes from baseline in the intervention groups ranged from a loss of 0.3 kg to 6.6 kg. In the control group, mean change ranged from a gain of 0.9 kg to a loss of 2.0 kg. Weight loss in both groups generally declined with longer follow-up (12-24 months). Interventions that prescribed both reduced energy intake (eg, ≥ 500 kcal/d) and increased physical activity (eg, ≥150 minutes a week of walking), with traditional behavioral therapy, generally produced larger weight loss than interventions without all 3 specific components. In the former trials, more treatment sessions, delivered in person or by telephone by trained interventionists, were associated with greater mean weight loss and likelihood of patients losing 5% or more of baseline weight. \n CONCLUSIONS AND RELEVANCE Intensive behavioral counseling can induce clinically meaningful weight loss, but there is little research on primary care practitioners providing such care. The present findings suggest that a range of trained interventionists, who deliver counseling in person or by telephone, could be considered for treating overweight or obesity in patients encountered in primary care settings.", "title": "Behavioral treatment of obesity in patients encountered in primary care settings: a systematic review." }, { "docid": "39532074", "text": "INTRODUCTION The hostile environment after spinal cord injury (SCI) can compromise effects of regenerative therapies. We hypothesized that optimizing the post-traumatic environment with QL6 self-assembling peptides (SAPs) before neural precursor cell (NPC) transplantation would improve cell survival, differentiation and functional recovery. \n METHODS A total of 90 Wistar rats received a clip-compression SCI at C7. Within each of two study arms, animals were randomized into 5 groups (NPC, SAP, NPC+SAP, vehicle, and sham). SAPs and NPCs were injected into the spinal cord 1day and 14days post-injury, respectively. Animals received growth factors over 7days and were immunosuppressed. Rats were sacrificed at 4weeks and sections of the cervical spinal cord prepared for immunohistochemistry (first study arm). Neurological function was assessed weekly for 8weeks using a battery of behavioral tests. Nine weeks post-SCI, the corticospinal tract was assessed using fiber-tracking (second arm). \n RESULTS SAP-treated animals had significantly more surviving NPCs which showed increased differentiation to neurons and oligodendrocytes compared to controls. SAPs alone or in combination with NPCs resulted in smaller intramedullary cysts and larger volume of preserved tissue compared to other groups. The combined treatment group showed reduced astrogliosis and chondroitin sulfate proteoglycan deposition. Synaptic connectivity was increased in the NPC and combined treatment groups. Corticospinal tract preservation and behavioral outcomes improved with combinatorial treatment. \n CONCLUSION Injecting SAPs after SCI enhances subsequent NPC survival, integration and differentiation and improves functional recovery. STATEMENT OF SIGNIFICANCE The hostile environment after spinal cord injury (SCI) can compromise effects of regenerative therapies. We hypothesized that improving this environment with self-assembling peptides (SAPs) before neural precursor cell (NPC) transplantation would support their beneficial effects. SAPs assemble once injected, providing a supportive scaffold for repair and regeneration. We investigated this in a rat model of spinal cord injury. More NPCs survived in SAP-treated animals and these showed increased differentiation compared to controls. SAPS alone or in combination with NPCs resulted in smaller cysts and larger volume of preserved tissue with the combined treatment also reducing scarring and improving behavioral outcomes. Overall, injection of SAPs was shown to improve the efficacy of NPC treatment, a promising finding for those with SCIs.", "title": "Self-assembling peptides optimize the post-traumatic milieu and synergistically enhance the effects of neural stem cell therapy after cervical spinal cord injury." }, { "docid": "7239105", "text": "Remarkable advances have been made in recent years towards therapeutics for cognitive impairment in individuals with Down syndrome (DS) by using mouse models. In this review, we briefly describe the phenotypes of mouse models that represent outcome targets for drug testing, the behavioral tests used to assess impairments in cognition and the known mechanisms of action of several drugs that are being used in preclinical studies or are likely to be tested in clinical trials. Overlaps in the distribution of targets and in the pathways that are affected by these diverse drugs in the trisomic brain suggest new avenues for DS research and drug development.", "title": "The use of mouse models to understand and improve cognitive deficits in Down syndrome" }, { "docid": "878526", "text": "Despite progress in the development of drugs that efficiently target cancer cells, treatments for metastatic tumours are often ineffective. The now well-established dependency of cancer cells on their microenvironment suggests that targeting the non-cancer-cell component of the tumour might form a basis for the development of novel therapeutic approaches. However, the as-yet poorly characterized contribution of host responses during tumour growth and metastatic progression represents a limitation to exploiting this approach. Here we identify neutrophils as the main component and driver of metastatic establishment within the (pre-)metastatic lung microenvironment in mouse breast cancer models. Neutrophils have a fundamental role in inflammatory responses and their contribution to tumorigenesis is still controversial. Using various strategies to block neutrophil recruitment to the pre-metastatic site, we demonstrate that neutrophils specifically support metastatic initiation. Importantly, we find that neutrophil-derived leukotrienes aid the colonization of distant tissues by selectively expanding the sub-pool of cancer cells that retain high tumorigenic potential. Genetic or pharmacological inhibition of the leukotriene-generating enzyme arachidonate 5-lipoxygenase (Alox5) abrogates neutrophil pro-metastatic activity and consequently reduces metastasis. Our results reveal the efficacy of using targeted therapy against a specific tumour microenvironment component and indicate that neutrophil Alox5 inhibition may limit metastatic progression.", "title": "Neutrophils support lung colonization of metastasis-initiating breast cancer cells" }, { "docid": "32463364", "text": "OBJECTIVES Prevention of cognitive decline and dementia with blood pressure lowering treatments has shown inconsistent results. We compared the effects of different classes of antihypertensive drugs on the incidence of dementia, and on cognitive function. \n METHODS We conducted a systematic review and included 19 randomized trials (18 515 individuals) and 11 studies (831 674 individuals) analysing the effects of antihypertensive treatment on cognition and on the incidence of dementia, respectively, in hypertensive patients without prior cerebrovascular disorders. Network meta-analysis was used for the comparison of antihypertensive classes. \n RESULTS Antihypertensive treatment, regardless of the drug class, had benefits on overall cognition [effect size 0.05, 95% confidence interval (CI) 0.02-0.07] and all cognitive functions except language. Antihypertensive treatment reduced the risk of all-cause dementia by 9%, with reference to the control group (hazard ratio 0.91, 95% CI 0.89-0.94), when randomized trials and observationnal studies were combined (n = 15). Result was not significant with randomized trials alone (n = 4). Angiotensin II receptor blockers (ARBs) had larger benefits than placebo on overall cognition (adjusted effect size 0.60 ± 0.18, P = 0.02). ARBs were more effective than β-blockers (0.67 ± 0.18, P = 0.01), diuretics (0.54 ± 0.19, P = 0.04) and angiotensin-converting enzyme inhibitors (0.47 ± 0.17, P = 0.04) in rank. The mean change in blood pressure did not differ significantly between the different antihypertensive drug classes. \n CONCLUSION Our results support the notion that antihypertensive treatment has beneficial effects on cognitive decline and prevention of dementia, and indicate that these effects may differ between drug classes with ARBs possibly being the most effective.", "title": "Antihypertensive classes, cognitive decline and incidence of dementia: a network meta-analysis." }, { "docid": "7965928", "text": "IMPORTANCE Concussion and subconcussive impacts have been associated with short-term disrupted cognitive performance in collegiate athletes, but there are limited data on their long-term neuroanatomic and cognitive consequences. \n OBJECTIVE To assess the relationships of concussion history and years of football experience with hippocampal volume and cognitive performance in collegiate football athletes. \n DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study conducted between June 2011 and August 2013 at a US psychiatric research institute specializing in neuroimaging among collegiate football players with a history of clinician-diagnosed concussion (n = 25), collegiate football players without a history of concussion (n = 25), and non-football-playing, age-, sex-, and education-matched healthy controls (n = 25). EXPOSURES History of clinician-diagnosed concussion and years of football experience. \n MAIN OUTCOMES AND MEASURES High-resolution anatomical magnetic resonance imaging was used to quantify brain volumes. Baseline scores on a computerized concussion-related cognitive battery were used for cognitive assessment in athletes. \n RESULTS Players with and without a history of concussion had smaller hippocampal volumes relative to healthy control participants (with concussion: t48 = 7.58; P < .001; mean difference, 1788 μL; 95% CI, 1317-2258 μL; without concussion: t48 = 4.35; P < .001, mean difference, 1027 μL; 95% CI, 556-1498 μL). Players with a history of concussion had smaller hippocampal volumes than players without concussion (t48 = 3.15; P < .001; mean difference, 761 μL; 95% CI, 280-1242 μL). In both athlete groups, there was a statistically significant inverse relationship between left hippocampal volume and number of years of football played (t46 = -3.62; P < .001; coefficient = -43.54; 95% CI, -67.66 to -19.41). Behavioral testing demonstrated no differences between athletes with and without a concussion history on 5 cognitive measures but did show an inverse correlation between years of playing football and reaction time (ρ42 = -0.43; 95% CI, -0.46 to -0.40; P = .005). \n CONCLUSIONS AND RELEVANCE Among a group of collegiate football athletes, there was a significant inverse relationship of concussion and years of football played with hippocampal volume. Years of football experience also correlated with slower reaction time. Further research is needed to determine the temporal relationships of these findings.", "title": "Relationship of collegiate football experience and concussion with hippocampal volume and cognitive outcomes." }, { "docid": "5836", "text": "Myelodysplastic syndromes (MDS) are age-dependent stem cell malignancies that share biological features of activated adaptive immune response and ineffective hematopoiesis. Here we report that myeloid-derived suppressor cells (MDSC), which are classically linked to immunosuppression, inflammation, and cancer, were markedly expanded in the bone marrow of MDS patients and played a pathogenetic role in the development of ineffective hematopoiesis. These clonally distinct MDSC overproduce hematopoietic suppressive cytokines and function as potent apoptotic effectors targeting autologous hematopoietic progenitors. Using multiple transfected cell models, we found that MDSC expansion is driven by the interaction of the proinflammatory molecule S100A9 with CD33. These 2 proteins formed a functional ligand/receptor pair that recruited components to CD33’s immunoreceptor tyrosine-based inhibition motif (ITIM), inducing secretion of the suppressive cytokines IL-10 and TGF-β by immature myeloid cells. S100A9 transgenic mice displayed bone marrow accumulation of MDSC accompanied by development of progressive multilineage cytopenias and cytological dysplasia. Importantly, early forced maturation of MDSC by either all-trans-retinoic acid treatment or active immunoreceptor tyrosine-based activation motif–bearing (ITAM-bearing) adapter protein (DAP12) interruption of CD33 signaling rescued the hematologic phenotype. These findings indicate that primary bone marrow expansion of MDSC driven by the S100A9/CD33 pathway perturbs hematopoiesis and contributes to the development of MDS.", "title": "Induction of myelodysplasia by myeloid-derived suppressor cells." }, { "docid": "18025240", "text": "OBJECTIVE To summarise the effects of anthelmintic drug treatment on growth and cognitive performance in children. \n DATA SOURCES Electronic databases: Cochrane Infectious Diseases Group controlled trial register, Cochrane controlled trials register, Embase, and Medline. Citations of all identified trials. Contact with the World Health Organization and field researchers. REVIEW METHODS Systematic review of randomised controlled trials in children aged 1-16 that compared anthelmintic treatment with placebo or no treatment. Assessment of validity and data abstraction conducted independently by two reviewers. \n MAIN OUTCOME MEASURES Growth and cognitive performance. \n RESULTS Thirty randomised controlled trials in more than 15 000 children were identified. Effects on mean weight were unremarkable, and heterogeneity was evident in the results. There were some positive effects on mean weight change in the trials reporting this outcome: after a single dose (any anthelmintic) the pooled estimates were 0.24 kg (95% confidence interval 0.15 kg to 0. 32 kg; fixed effects model assumed) and 0.38 kg (0.01 kg to 0.77 kg; random effects model assumed). Results from trials of multiple doses showed mean weight change in up to one year of follow up of 0.10 kg (0.04 kg to 0.17 kg; fixed effects) or 0.15 kg (0.00 to 0.30; random effects). At more than one year of follow up, mean weight change was 0.12 kg (-0.02 kg to 0.26 kg; fixed effects) and 0.43 (-0.61 to 1. 47; random effects). Results from studies of cognitive performance were inconclusive. \n CONCLUSIONS There is some limited evidence that routine treatment of children in areas where helminths are common has effects on weight gain, but this is not consistent between trials. There is insufficient evidence as to whether this intervention improves cognitive performance.", "title": "Effects of treatment for intestinal helminth infection on growth and cognitive performance in children: systematic review of randomised trials." } ]

[ { "docid": "11614737", "text": "IMPORTANCE Combining pharmacotherapies for tobacco-dependence treatment may increase smoking abstinence. \n OBJECTIVE To determine efficacy and safety of varenicline and bupropion sustained-release (SR; combination therapy) compared with varenicline (monotherapy) in cigarette smokers. \n DESIGN, SETTING, AND PARTICIPANTS Randomized, blinded, placebo-controlled multicenter clinical trial with a 12-week treatment period and follow-up through week 52 conducted between October 2009 and April 2013 at 3 midwestern clinical research sites. Five hundred six adult (≥18 years) cigarette smokers were randomly assigned and 315 (62%) completed the study. \n INTERVENTIONS Twelve weeks of varenicline and bupropion SR or varenicline and placebo. \n MAIN OUTCOMES AND MEASURES Primary outcome was abstinence rates at week 12, defined as prolonged (no smoking from 2 weeks after the target quit date) abstinence and 7-day point-prevalence (no smoking past 7 days) abstinence. Secondary outcomes were prolonged and point-prevalence smoking abstinence rates at weeks 26 and 52. Outcomes were biochemically confirmed. \n RESULTS At 12 weeks, 53.0% of the combination therapy group achieved prolonged smoking abstinence and 56.2% achieved 7-day point-prevalence smoking abstinence compared with 43.2% and 48.6% in varenicline monotherapy (odds ratio [OR], 1.49; 95% CI, 1.05-2.12; P = .03 and OR, 1.36; 95% CI, 0.95-1.93; P = .09, respectively). At 26 weeks, 36.6% of the combination therapy group achieved prolonged and 38.2% achieved 7-day point-prevalence smoking abstinence compared with 27.6% and 31.9% in varenicline monotherapy (OR, 1.52; 95% CI, 1.04-2.22; P = .03 and OR, 1.32; 95% CI, 0.91-1.91; P = .14, respectively). At 52 weeks, 30.9% of the combination therapy group achieved prolonged and 36.6% achieved 7-day point-prevalence smoking abstinence compared with 24.5% and 29.2% in varenicline monotherapy (OR, 1.39; 95% CI, 0.93-2.07; P = .11 and OR, 1.40; 95% CI, 0.96-2.05; P = .08, respectively). Participants receiving combination therapy reported more anxiety (7.2% vs 3.1%; P = .04) and depressive symptoms (3.6% vs 0.8%; P = .03). \n CONCLUSIONS AND RELEVANCE Among cigarette smokers, combined use of varenicline and bupropion, compared with varenicline alone, increased prolonged abstinence but not 7-day point prevalence at 12 and 26 weeks. Neither outcome was significantly different at 52 weeks. Further research is required to determine the role of combination therapy in smoking cessation. \n TRIAL REGISTRATION clinicaltrials.gov Identifier: http://clinicaltrials.gov/show/NCT00935818.", "title": "Combination varenicline and bupropion SR for tobacco-dependence treatment in cigarette smokers: a randomized trial." } ]

[ { "docid": "5114940", "text": "BACKGROUND Smoking is the leading preventable cause of illness and premature death worldwide. Some medications have been proven to help people to quit, with three licensed for this purpose in Europe and the USA: nicotine replacement therapy (NRT), bupropion, and varenicline. Cytisine (a treatment pharmacologically similar to varenicline) is also licensed for use in Russia and some of the former socialist economy countries. Other therapies, including nortriptyline, have also been tested for effectiveness. \n OBJECTIVES How do NRT, bupropion and varenicline compare with placebo and with each other in achieving long-term abstinence (six months or longer)? How do the remaining treatments compare with placebo in achieving long-term abstinence? How do the risks of adverse and serious adverse events (SAEs) compare between the treatments, and are there instances where the harms may outweigh the benefits? \n METHODS The overview is restricted to Cochrane reviews, all of which include randomised trials. Participants are usually adult smokers, but we exclude reviews of smoking cessation for pregnant women and in particular disease groups or specific settings. We cover nicotine replacement therapy (NRT), antidepressants (bupropion and nortriptyline), nicotine receptor partial agonists (varenicline and cytisine), anxiolytics, selective type 1 cannabinoid receptor antagonists (rimonabant), clonidine, lobeline, dianicline, mecamylamine, Nicobrevin, opioid antagonists, nicotine vaccines, and silver acetate. Our outcome for benefit is continuous or prolonged abstinence at least six months from the start of treatment. Our outcome for harms is the incidence of serious adverse events associated with each of the treatments. We searched the Cochrane Database of Systematic Reviews (CDSR) in The Cochrane Library, for any reviews with 'smoking' in the title, abstract or keyword fields. The last search was conducted in November 2012. We assessed methodological quality using a revised version of the AMSTAR scale. For NRT, bupropion and varenicline we conducted network meta-analyses, comparing each with the others and with placebo for benefit, and varenicline and bupropion for risks of serious adverse events. \n MAIN RESULTS We identified 12 treatment-specific reviews. The analyses covered 267 studies, involving 101,804 participants. Both NRT and bupropion were superior to placebo (odds ratios (OR) 1.84; 95% credible interval (CredI) 1.71 to 1.99, and 1.82; 95% CredI 1.60 to 2.06 respectively). Varenicline increased the odds of quitting compared with placebo (OR 2.88; 95% CredI 2.40 to 3.47). Head-to-head comparisons between bupropion and NRT showed equal efficacy (OR 0.99; 95% CredI 0.86 to 1.13). Varenicline was superior to single forms of NRT (OR 1.57; 95% CredI 1.29 to 1.91), and to bupropion (OR 1.59; 95% CredI 1.29 to 1.96). Varenicline was more effective than nicotine patch (OR 1.51; 95% CredI 1.22 to 1.87), than nicotine gum (OR 1.72; 95% CredI 1.38 to 2.13), and than 'other' NRT (inhaler, spray, tablets, lozenges; OR 1.42; 95% CredI 1.12 to 1.79), but was not more effective than combination NRT (OR 1.06; 95% CredI 0.75 to 1.48). Combination NRT also outperformed single formulations. The four categories of NRT performed similarly against each other, apart from 'other' NRT, which was marginally more effective than NRT gum (OR 1.21; 95% CredI 1.01 to 1.46). Cytisine (a nicotine receptor partial agonist) returned positive findings (risk ratio (RR) 3.98; 95% CI 2.01 to 7.87), without significant adverse events or SAEs. Across the 82 included and excluded bupropion trials, our estimate of six seizures in the bupropion arms versus none in the placebo arms was lower than the expected rate (1:1000), at about 1:1500. SAE meta-analysis of the bupropion studies demonstrated no excess of neuropsychiatric (RR 0.88; 95% CI 0.31 to 2.50) or cardiovascular events (RR 0.77; 95% CI 0.37 to 1.59). SAE meta-analysis of 14 varenicline trials found no difference between the varenicline and placebo arms (RR 1.06; 95% CI 0.72 to 1.55), and subgroup analyses detected no significant excess of neuropsychiatric events (RR 0.53; 95% CI 0.17 to 1.67), or of cardiac events (RR 1.26; 95% CI 0.62 to 2.56). Nortriptyline increased the chances of quitting (RR 2.03; 95% CI 1.48 to 2.78). Neither nortriptyline nor bupropion were shown to enhance the effect of NRT compared with NRT alone. Clonidine increased the chances of quitting (RR 1.63; 95% CI 1.22 to 2.18), but this was offset by a dose-dependent rise in adverse events. Mecamylamine in combination with NRT may increase the chances of quitting, but the current evidence is inconclusive. Other treatments failed to demonstrate a benefit compared with placebo. Nicotine vaccines are not yet licensed for use as an aid to smoking cessation or relapse prevention. Nicobrevin's UK license is now revoked, and the manufacturers of rimonabant, taranabant and dianicline are no longer supporting the development or testing of these treatments. AUTHORS' CONCLUSIONS NRT, bupropion, varenicline and cytisine have been shown to improve the chances of quitting. Combination NRT and varenicline are equally effective as quitting aids. Nortriptyline also improves the chances of quitting. On current evidence, none of the treatments appear to have an incidence of adverse events that would mitigate their use. Further research is warranted into the safety of varenicline and into cytisine's potential as an effective and affordable treatment, but not into the efficacy and safety of NRT.", "title": "Pharmacological interventions for smoking cessation: an overview and network meta-analysis." }, { "docid": "24019260", "text": "Alcohol dependence is a disease that impacts millions of individuals worldwide. There has been some progress with pharmacotherapy for alcohol-dependent individuals; however, there remains a critical need for the development of novel and additional therapeutic approaches. Alcohol and nicotine are commonly abused together, and there is evidence that neuronal nicotinic acetylcholine receptors (nAChRs) play a role in both alcohol and nicotine dependence. Varenicline, a partial agonist at the alpha4beta2 nAChRs, reduces nicotine intake and was recently approved as a smoking cessation aid. We have investigated the role of varenicline in the modulation of ethanol consumption and seeking using three different animal models of drinking. We show that acute administration of varenicline, in doses reported to reduce nicotine reward, selectively reduced ethanol but not sucrose seeking using an operant self-administration drinking paradigm and also decreased voluntary ethanol but not water consumption in animals chronically exposed to ethanol for 2 months before varenicline treatment. Furthermore, chronic varenicline administration decreased ethanol consumption, which did not result in a rebound increase in ethanol intake when the varenicline was no longer administered. The data suggest that the alpha4beta2 nAChRs may play a role in ethanol-seeking behaviors in animals chronically exposed to ethanol. The selectivity of varenicline in decreasing ethanol consumption combined with its reported safety profile and mild side effects in humans suggest that varenicline may prove to be a treatment for alcohol dependence.", "title": "Varenicline, an alpha4beta2 nicotinic acetylcholine receptor partial agonist, selectively decreases ethanol consumption and seeking." }, { "docid": "34369306", "text": "BACKGROUND A double-blind RCT on the short-term efficacy of nicotine patches compared to placebo patches among Dutch adolescents was conducted. The findings demonstrated that nicotine patches are efficacious for smoking cessation at end-of-treatment; however, only in highly compliant participants. We tested whether the effects of NRT also held in 6- (T7) and 12-month (T8) follow-up assessments. \n METHODS Adolescents aged 12-18 years, who smoked at least seven cigarettes a day and who were motivated to quit smoking were recruited at school yards and randomly assigned to either a nicotine patch (n=182) or a placebo patch (n=180) condition according to a computer generated list. Participants (N=257, age: 16.7 ± 1.13 years) attended an information meeting followed by a 6- or 9-week treatment. Smoking cessation, compliance, and potential covariates were measured by means of online questionnaires. Smoking cessation at T8 was biochemically validated by saliva cotinine. \n RESULTS At T7, 8.1% and 5.7% of participants were abstinent in the nicotine and placebo patch groups, respectively. At T8, abstinence was 4.4% and 6.6%, respectively. Intention-to-treat analyses showed no significant effects of NRT on abstinence rates at T7 (OR=1.54, 95% CI=0.57, 4.16) and validated abstinence rates at T8 (OR=0.64, 95% CI=0.21, 1.93) neither after considering compliance nor after adjusting for covariates. \n CONCLUSIONS NRT fails in helping adolescents quit smoking at 6- and 12-month follow-ups. This finding suggests that a more intensive approach is needed to assist youngsters in their quit attempts.", "title": "Long-term efficacy of nicotine replacement therapy for smoking cessation in adolescents: a randomized controlled trial." }, { "docid": "5551138", "text": "This article reviews the efficacy of nortriptyline for smoking cessation based on a meta-analysis of the Cochrane Library. Six placebo-controlled trials have shown nortriptyline (75-100 mg) doubles quit rates (OR = 2.1). Between 4% and 12% of smokers dropped out because of adverse events, but no serious adverse events occurred. The efficacy of nortriptyline did not appear to be related to its antidepressant actions. Nortriptyline is an efficacious aid to smoking cessation with a magnitude of effect similar to that for bupropion and nicotine replacement therapies. Whether nortriptyline produces serious side effects at these doses in healthy, nondepressed smokers remains unclear because it has been tested in only 500 smokers. The finding that nortriptyline and bupropion are effective for smoking cessation but that selective serotonin-reuptake inhibitors are not suggests that dopaminergic or adrenergic, but not serotonergic, activity is important for cessation efficacy. Until further studies can verify a low incidence of significant adverse events, nortriptyline should be a second-line treatment for smoking cessation.", "title": "Nortriptyline for smoking cessation: a review." }, { "docid": "25816994", "text": "BACKGROUND Angiotensin receptor blockers (ARB) and angiotensin converting enzyme (ACE) inhibitors are known to reduce proteinuria. Their combination might be more effective than either treatment alone, but long-term data for comparative changes in renal function are not available. We investigated the renal effects of ramipril (an ACE inhibitor), telmisartan (an ARB), and their combination in patients aged 55 years or older with established atherosclerotic vascular disease or with diabetes with end-organ damage. \n METHODS The trial ran from 2001 to 2007. After a 3-week run-in period, 25 620 participants were randomly assigned to ramipril 10 mg a day (n=8576), telmisartan 80 mg a day (n=8542), or to a combination of both drugs (n=8502; median follow-up was 56 months), and renal function and proteinuria were measured. The primary renal outcome was a composite of dialysis, doubling of serum creatinine, and death. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00153101. \n FINDINGS 784 patients permanently discontinued randomised therapy during the trial because of hypotensive symptoms (406 on combination therapy, 149 on ramipril, and 229 on telmisartan). The number of events for the composite primary outcome was similar for telmisartan (n=1147 [13.4%]) and ramipril (1150 [13.5%]; hazard ratio [HR] 1.00, 95% CI 0.92-1.09), but was increased with combination therapy (1233 [14.5%]; HR 1.09, 1.01-1.18, p=0.037). The secondary renal outcome, dialysis or doubling of serum creatinine, was similar with telmisartan (189 [2.21%]) and ramipril (174 [2.03%]; HR 1.09, 0.89-1.34) and more frequent with combination therapy (212 [2.49%]: HR 1.24, 1.01-1.51, p=0.038). Estimated glomerular filtration rate (eGFR) declined least with ramipril compared with telmisartan (-2.82 [SD 17.2] mL/min/1.73 m(2)vs -4.12 [17.4], p<0.0001) or combination therapy (-6.11 [17.9], p<0.0001). The increase in urinary albumin excretion was less with telmisartan (p=0.004) or with combination therapy (p=0.001) than with ramipril. \n INTERPRETATION In people at high vascular risk, telmisartan's effects on major renal outcomes are similar to ramipril. Although combination therapy reduces proteinuria to a greater extent than monotherapy, overall it worsens major renal outcomes.", "title": "Renal outcomes with telmisartan, ramipril, or both, in people at high vascular risk (the ONTARGET study): a multicentre, randomised, double-blind, controlled trial." }, { "docid": "1759213", "text": "OBJECTIVE To examine the safety of using aliskiren combined with agents used to block the renin-angiotensin system. \n DESIGN Systematic review and meta-analysis of randomised controlled trials. \n DATA SOURCES Medline, Embase, the Cochrane Library, and two trial registries, published up to 7 May 2011. STUDY SELECTION Published and unpublished randomised controlled trials that compared combined treatment using aliskiren and angiotensin converting enzyme inhibitors or angiotensin receptor blockers with monotherapy using these agents for at least four weeks and that provided numerical data on the adverse event outcomes of hyperkalaemia and acute kidney injury. A random effects model was used to calculate pooled risk ratios and 95% confidence intervals for these outcomes. \n RESULTS 10 randomised controlled studies (4814 participants) were included in the analysis. Combination therapy with aliskiren and angiotensin converting enzyme inhibitors or angiotensin receptor blockers significantly increased the risk of hyperkalaemia compared with monotherapy using angiotensin converting enzymes or angiotensin receptor blockers (relative risk 1.58, 95% confidence interval 1.24 to 2.02) or aliskiren alone (1.67, 1.01 to 2.79). The risk of acute kidney injury did not differ significantly between the combined therapy and monotherapy groups (1.14, 0.68 to 1.89). \n CONCLUSION Use of aliskerin in combination with angiotensin converting enzyme inhibitors or angiotensin receptor blockers is associated with an increased risk for hyperkalaemia. The combined use of these agents warrants careful monitoring of serum potassium levels.", "title": "The effect of combination treatment with aliskiren and blockers of the renin-angiotensin system on hyperkalaemia and acute kidney injury: systematic review and meta-analysis" }, { "docid": "8570690", "text": "INTRODUCTION Topiramate (TOP) blocks glutamate receptors and facilitates GABA (γ-aminobutyric acid) neurotransmission, effects that may facilitate smoking cessation. We compared the effects of behavioral counseling combined with (a) TOP, (b) TOP/nicotine patch (TOP/NIC), or (c) placebo (PLC) for smoking cessation. \n METHODS We conducted a 10-week randomized trial in which subjects and research personnel were blinded to TOP versus PLC but not to the TOP/NIC patch condition. In groups receiving TOP, the medication dosage was titrated gradually up to 200 mg/day. The smoking quit date (QD) was scheduled after 2 weeks of medication treatment. NIC (21 mg) was started on the QD in subjects randomized to the TOP/NIC condition. The main outcome measure was the end-of-treatment, 4-week continuous abstinence rate (CAR; biochemically confirmed). \n RESULTS Fifty-seven subjects were randomized to treatment. The 4-week CAR was 1 of 19 (5%) in the PLC group, 5 of 19 (26%) in the TOP group, and 7 of 19 (37%) in the TOP/NIC group (p = .056). Pairwise comparisons showed a difference between TOP/NIC and PLC (p = .042) and a nonsignificant difference between TOP and PLC (p = .18). The PLC group gained 0.37 lb/week, the TOP group lost 0.41 lb/week, and the TOP/NIC group lost 0.07 lb/week (p = .004). Pairwise comparisons showed a difference between TOP and PLC (p < .001) and between TOP/NIC and PLC groups (p = .035). Paresthesia was more frequent in subjects on TOP than PLC (p = .011). \n CONCLUSIONS TOP, alone or in combination with the NIC, resulted in a numerically higher quit rate than PLC and decreased weight. A larger, PLC-controlled trial is needed to confirm these findings.", "title": "Topiramate for smoking cessation: a randomized, placebo-controlled pilot study." }, { "docid": "18340282", "text": "BACKGROUND Information is scarce about the combined effects on breast cancer incidence of low-penetrance genetic susceptibility polymorphisms and environmental factors (reproductive, behavioural, and anthropometric risk factors for breast cancer). To test for evidence of gene-environment interactions, we compared genotypic relative risks for breast cancer across the other risk factors in a large UK prospective study. \n METHODS We tested gene-environment interactions in 7610 women who developed breast cancer and 10 196 controls without the disease, studying the effects of 12 polymorphisms (FGFR2-rs2981582, TNRC9-rs3803662, 2q35-rs13387042, MAP3K1-rs889312, 8q24-rs13281615, 2p-rs4666451, 5p12-rs981782, CASP8-rs1045485, LSP1-rs3817198, 5q-rs30099, TGFB1-rs1982073, and ATM-rs1800054) in relation to prospectively collected information about ten established environmental risk factors (age at menarche, parity, age at first birth, breastfeeding, menopausal status, age at menopause, use of hormone replacement therapy, body-mass index, height, and alcohol consumption). \n FINDINGS After allowance for multiple testing none of the 120 comparisons yielded significant evidence of a gene-environment interaction. By contrast with previous suggestions, there was little evidence that the genotypic relative risks were affected by use of hormone replacement therapy, either overall or for oestrogen-receptor-positive disease. Only one of the 12 polymorphisms was correlated with any of the ten other risk factors: carriers of the high-risk C allele of MAP3K1-rs889312 were significantly shorter than non-carriers (mean height 162.4 cm [95% CI 162.1-162.7] vs 163.1 cm [162.9-163.2]; p=0.01 after allowance for multiple testing). \n INTERPRETATION Risks of breast cancer associated with low-penetrance susceptibility polymorphisms do not vary significantly with these ten established environmental risk factors. \n FUNDING Cancer Research UK and the UK Medical Research Council.", "title": "Gene–environment interactions in 7610 women with breast cancer: prospective evidence from the Million Women Study" }, { "docid": "6191684", "text": "CONTEXT Chronic tension-type headaches are characterized by near-daily headaches and often are difficult to manage in primary practice. Behavioral and pharmacological therapies each appear modestly effective, but data are lacking on their separate and combined effects. \n OBJECTIVE To evaluate the clinical efficacy of behavioral and pharmacological therapies, singly and combined, for chronic tension-type headaches. \n DESIGN AND SETTING Randomized placebo-controlled trial conducted from August 1995 to January 1998 at 2 outpatient sites in Ohio. \n PARTICIPANTS Two hundred three adults (mean age, 37 years; 76% women) with diagnosis of chronic tension-type headaches (mean, 26 headache d/mo). \n INTERVENTIONS Participants were randomly assigned to receive tricyclic antidepressant (amitriptyline hydrochloride, up to 100 mg/d, or nortriptyline hydrochloride, up to 75 mg/d) medication (n = 53), placebo (n = 48), stress management (eg, relaxation, cognitive coping) therapy (3 sessions and 2 telephone contacts) plus placebo (n = 49), or stress management therapy plus antidepressant medication (n = 53). \n MAIN OUTCOME MEASURES Monthly headache index scores calculated as the mean of pain ratings (0-10 scale) recorded by participants in a daily diary 4 times per day; number of days per month with at least moderate pain (pain rating >/=5), analgesic medication use, and Headache Disability Inventory scores, compared by intervention group. \n RESULTS Tricyclic antidepressant medication and stress management therapy each produced larger reductions in headache activity, analgesic medication use, and headache-related disability than placebo, but antidepressant medication yielded more rapid improvements in headache activity. Combined therapy was more likely to produce clinically significant (>/=50%) reductions in headache index scores (64% of participants) than antidepressant medication (38% of participants; P =.006), stress management therapy (35%; P =.003), or placebo (29%; P =.001). On other measures the combined therapy and its 2 component therapies produced similar outcomes. \n CONCLUSIONS Our results indicate that antidepressant medication and stress management therapy are each modestly effective in treating chronic tension-type headaches. Combined therapy may improve outcome relative to monotherapy.", "title": "Management of chronic tension-type headache with tricyclic antidepressant medication, stress management therapy, and their combination: a randomized controlled trial." }, { "docid": "39532074", "text": "INTRODUCTION The hostile environment after spinal cord injury (SCI) can compromise effects of regenerative therapies. We hypothesized that optimizing the post-traumatic environment with QL6 self-assembling peptides (SAPs) before neural precursor cell (NPC) transplantation would improve cell survival, differentiation and functional recovery. \n METHODS A total of 90 Wistar rats received a clip-compression SCI at C7. Within each of two study arms, animals were randomized into 5 groups (NPC, SAP, NPC+SAP, vehicle, and sham). SAPs and NPCs were injected into the spinal cord 1day and 14days post-injury, respectively. Animals received growth factors over 7days and were immunosuppressed. Rats were sacrificed at 4weeks and sections of the cervical spinal cord prepared for immunohistochemistry (first study arm). Neurological function was assessed weekly for 8weeks using a battery of behavioral tests. Nine weeks post-SCI, the corticospinal tract was assessed using fiber-tracking (second arm). \n RESULTS SAP-treated animals had significantly more surviving NPCs which showed increased differentiation to neurons and oligodendrocytes compared to controls. SAPs alone or in combination with NPCs resulted in smaller intramedullary cysts and larger volume of preserved tissue compared to other groups. The combined treatment group showed reduced astrogliosis and chondroitin sulfate proteoglycan deposition. Synaptic connectivity was increased in the NPC and combined treatment groups. Corticospinal tract preservation and behavioral outcomes improved with combinatorial treatment. \n CONCLUSION Injecting SAPs after SCI enhances subsequent NPC survival, integration and differentiation and improves functional recovery. STATEMENT OF SIGNIFICANCE The hostile environment after spinal cord injury (SCI) can compromise effects of regenerative therapies. We hypothesized that improving this environment with self-assembling peptides (SAPs) before neural precursor cell (NPC) transplantation would support their beneficial effects. SAPs assemble once injected, providing a supportive scaffold for repair and regeneration. We investigated this in a rat model of spinal cord injury. More NPCs survived in SAP-treated animals and these showed increased differentiation compared to controls. SAPS alone or in combination with NPCs resulted in smaller cysts and larger volume of preserved tissue with the combined treatment also reducing scarring and improving behavioral outcomes. Overall, injection of SAPs was shown to improve the efficacy of NPC treatment, a promising finding for those with SCIs.", "title": "Self-assembling peptides optimize the post-traumatic milieu and synergistically enhance the effects of neural stem cell therapy after cervical spinal cord injury." }, { "docid": "13619127", "text": "OBJECTIVE To assess the risks of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia in patients with type 2 diabetes associated with prescribed diabetes drugs, particularly newer agents including gliptins or glitazones (thiazolidinediones). \n DESIGN Open cohort study in primary care. \n SETTING 1243 practices contributing data to the QResearch database in England. \n PARTICIPANTS 469,688 patients with type 2 diabetes aged 25-84 years between 1 April 2007 and 31 January 2015. EXPOSURES Hypoglycaemic agents (glitazones, gliptins, metformin, sulphonylureas, insulin, and other) alone and in combination. \n MAIN OUTCOME MEASURES First recorded diagnoses of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia recorded on patients' primary care, mortality, or hospital records. Cox models estimated hazard ratios for diabetes treatments adjusting for potential confounders. \n RESULTS 21,308 (4.5%) and 32,533 (6.9%) patients received prescriptions for glitazones and gliptins during follow-up, respectively. Compared with non-use, glitazones were associated with a decreased risk of blindness (adjusted hazard ratio 0.71, 95% confidence interval 0.57 to 0.89; rate 14.4 per 10,000 person years of exposure) and an increased risk of hypoglycaemia (1.22, 1.10 to 1.37; 65.1); gliptins were associated with a decreased risk of hypoglycaemia (0.86, 0.77 to 0.96; 45.8). Although the numbers of patients prescribed gliptin monotherapy or glitazones monotherapy were relatively low, there were significantly increased risks of severe kidney failure compared with metformin monotherapy (adjusted hazard ratio 2.55, 95% confidence interval 1.13 to 5.74). We found significantly lower risks of hyperglycaemia among patients prescribed dual therapy involving metformin with either gliptins (0.78, 0.62 to 0.97) or glitazones (0.60, 0.45 to 0.80) compared with metformin monotherapy. Patients prescribed triple therapy with metformin, sulphonylureas, and either gliptins (adjusted hazard ratio 5.07, 95% confidence interval 4.28 to 6.00) or glitazones (6.32, 5.35 to 7.45) had significantly higher risks of hypoglycaemia than those prescribed metformin monotherapy, but these risks were similar to those involving dual therapy with metformin and sulphonylureas (6.03, 5.47 to 6.63). Patients prescribed triple therapy with metformin, sulphonylureas, and glitazones had a significantly reduced risk of blindness compared with metformin monotherapy (0.67, 0.48 to 0.94). \n CONCLUSIONS We have found lower risks of hyperglycaemia among patients prescribed dual therapy involving metformin with either gliptins or glitazones compared with metformin alone. Compared with metformin monotherapy, triple therapy with metformin, sulphonylureas, and either gliptins or glitazones was associated with an increased risk of hypoglycaemia, which was similar to the risk for dual therapy with metformin and sulphonylureas. Compared with metformin monotherapy, triple therapy with metformin, sulphonylureas, and glitazones was associated with a reduced risk of blindness. These results, while subject to residual confounding, could have implications for the prescribing of hypoglycaemic drugs.", "title": "Diabetes treatments and risk of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia: open cohort study in primary care" }, { "docid": "24494539", "text": "OBJECTIVE To observe the clinical effects of acupuncture combined with auricular point sticking based on the western medication for post stroke depression (PSD). \n METHODS Sixty patients with PSD were randomly assigned into an acupuncture plus auricular application group (a combination group) and a medication group, 30 cases in each one. 20 mg paroxetine hydrochloride was prescribed orally in the medication group, once a day for continuous 8 weeks. Based on the above treatment, 30-minute acupuncture was used in the combination group for 8 weeks at Baihui (GV 20), Sishencong (EX-HN 1), Shenting (GV 24), Yintang (GV 29), Shenmen (HT 7), Neiguan (PC 6), Taichong (LR 3), Hegu (LI 4), Zusanli (ST 36), Sanyinjiao (SP 6) and Fenglong (ST 40), once the other day and three times a week. Auricular point sticking therapy for 8 weeks was applied at shenmen (TF4), pizhixia (AT4), xin (CO15), and gan (CO12), with pressing 3 times a day and once 3-5 days. The total score and each factor scores of Hamilton's depression scale (HAMD) were observed in the two groups before and after treatment, and Asberg's antidepressant side-effect rating scale (SERS) and clinical effect were evaluated. \n RESULTS After treatment, the total HAMD scores of the two groups decreased compared with those before treatment (both P<0.05), with better effect in the combination group (P<0.05). The scores of the combination group after treatment were lower than those in the medication group, including the anxiety/somatization factor, sleep disturbance factor, hopelessness factor (all P<0.05). The total effective rate of the combination group was 86.7% (26/30), which was better than 66.7% (20/30) of the medication group (P<0.05). The SERS score of the combination group was lower than that of the medication group (P<0.05). \n CONCLUSIONS Acupuncture combined with auricular point sticking can improve the clinical symptoms and are effective and safe for PSD.", "title": "[Acupuncture combined with auricular point sticking therapy for post stroke depression:a randomized controlled trial]." }, { "docid": "24697979", "text": "OBJECTIVE To observe the effects on post-stroke depression treated with acupuncture at the acu points based on ziwuliuzhu (the midnight-noon ebb-flow theory). \n METHODS Ninety-three patients were randomized into a comprehensive group, a ziwuliuzhu group and a prozac group, 31 cases in each group. In the ziwuliuzhu group, acupuncture was applied to the acupoints based on ziwuliuzhu, once a day, 5 times in a week. In the prozac group, fluoxertine hydrochloride (prozac) was prescribed for oral administration, once a day, 20 mg each time. In the comprehensive group, acupuncture based on ziwuliuzhu combined with the oral administration of prozac were adopted and the treatment frequency was the same as the ziwuliuzhu group and the prozac group. The 4-week treatment was taken as one session in the three groups and 6 sessions were required totally. The clinical efficacy and the Hamilton depression rating scale (HAMD) score and the adverse reaction were compared among the 3 groups. \n RESULTS The total effective rate was 96.8% (30/31) in the comprehensive group, better than 83.9% (26/31) in the ziwuliuzhu group and 80. 6% (25/31) in the prozac group (both P<0.05). In 4, 12 and 24 weeks of treatment, HAMD score was lower significantly than that before the treatment in the three groups (all P<0.05), and the score in the comprehensive group at each time point after treatment was lower than the other two groups (all P<0.05). In 4 and 12 weeks of treatment, there were not different significantly between the ziwuliuzhu group and the prozac group (both P>0.05). In 24 weeks of treatment, HAMD score in the ziwuliuzhu group was lower than that in the prozac group (P<0.05). For the adverse reaction, there were 2 cases in the comprehensive group, 6 cases in the prozac group and 0 case in the ziwzuliuzhu group. \n CONCLUSION The comprehensive therapy of acupuncture at the acupoints based on ziwuliuzhu and oral administration of prozac is superior to either the simple oral administration of prozac or the ziwuliuzhu acu-puncture in terms of clinical efficacy and the improvements in depressive state. Regarding the clinical efficacy, the impact of simple ziwuliuzhu acupuncture is not different significantly as compared with the simple oral administration of prozac, but it is better than the simple oral administration of prozac in terms of the long-term HAMD score and safety.", "title": "[Efficacy on post-stroke depression treated with acupuncture at the acupoints based on ziwuliuzhu and prozac]." }, { "docid": "5687200", "text": "AIMS The aim of this study was to compare the effects of calorie-restricted vegetarian and conventional diabetic diets alone and in combination with exercise on insulin resistance, visceral fat and oxidative stress markers in subjects with Type 2 diabetes. \n METHODS A 24-week, randomized, open, parallel design was used. Seventy-four patients with Type 2 diabetes were randomly assigned to either the experimental group (n = 37), which received a vegetarian diet, or the control group (n = 37), which received a conventional diabetic diet. Both diets were isocaloric, calorie restricted (-500 kcal/day). All meals during the study were provided. The second 12 weeks of the diet were combined with aerobic exercise. Participants were examined at baseline, 12 weeks and 24 weeks. Primary outcomes were: insulin sensitivity measured by hyperinsulinaemic isoglycaemic clamp; volume of visceral and subcutaneous fat measured by magnetic resonance imaging; and oxidative stress measured by thiobarbituric acid reactive substances. Analyses were by intention to treat. \n RESULTS Forty-three per cent of participants in the experimental group and 5% of participants in the control group reduced diabetes medication (P < 0.001). Body weight decreased more in the experimental group than in the control group [-6.2 kg (95% CI -6.6 to -5.3) vs. -3.2 kg (95% CI -3.7 to -2.5); interaction group × time P = 0.001]. An increase in insulin sensitivity was significantly greater in the experimental group than in the control group [30% (95% CI 24.5-39) vs. 20% (95% CI 14-25), P = 0.04]. A reduction in both visceral and subcutaneous fat was greater in the experimental group than in the control group (P = 0.007 and P = 0.02, respectively). Plasma adiponectin increased (P = 0.02) and leptin decreased (P = 0.02) in the experimental group, with no change in the control group. Vitamin C, superoxide dismutase and reduced glutathione increased in the experimental group (P = 0.002, P < 0.001 and P = 0.02, respectively). Differences between groups were greater after the addition of exercise training. Changes in insulin sensitivity and enzymatic oxidative stress markers correlated with changes in visceral fat. \n CONCLUSIONS A calorie-restricted vegetarian diet had greater capacity to improve insulin sensitivity compared with a conventional diabetic diet over 24 weeks. The greater loss of visceral fat and improvements in plasma concentrations of adipokines and oxidative stress markers with this diet may be responsible for the reduction of insulin resistance. The addition of exercise training further augmented the improved outcomes with the vegetarian diet.", "title": "Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes" }, { "docid": "14482051", "text": "BACKGROUND Panobinostat is a histone deacetylase inhibitor with antineoplastic and antiangiogenic effects in glioma that may work synergistically with bevacizumab. We conducted a multicenter phase II trial of panobinostat combined with bevacizumab in patients with recurrent high-grade glioma (HGG). \n METHODS Patients with recurrent HGG were treated with oral panobinostat 30 mg 3 times per week, every other week, in combination with bevacizumab 10 mg/kg every other week. The primary endpoint was a 6-month progression-fee survival (PFS6) rate for participants with recurrent glioblastoma (GBM). Patients with recurrent anaplastic glioma (AG) were evaluated as an exploratory arm of the study. \n RESULTS At interim analysis, the GBM arm did not meet criteria for continued accrual, and the GBM arm was closed. A total of 24 patients with GBM were accrued prior to closure. The PFS6 rate was 30.4% (95%, CI 12.4%-50.7%), median PFS was 5 months (range, 3-9 months), and median overall survival (OS) was 9 months (range, 6-19 months). Accrual in the AG arm continued to completion, and a total of 15 patients were enrolled. The PFS6 rate was 46.7% (range, 21%-73%), median PFS was 7 months (range, 2-10 months), and median OS was 17 months (range, 5 months-27 months). \n CONCLUSIONS This phase II study of panobinostat and bevacizumab in participants with recurrent GBM did not meet criteria for continued accrual, and the GBM cohort of the study was closed. Although it was reasonably well tolerated, the addition of panobinostat to bevacizumab did not significantly improve PFS6 compared with historical controls of bevacizumab monotherapy in either cohort.", "title": "Phase II study of panobinostat in combination with bevacizumab for recurrent glioblastoma and anaplastic glioma." }, { "docid": "10617916", "text": "Background. Artemisinin-based combination therapy (ACT) reduces microscopically confirmed gametocytemia and mosquito infection. However, molecular techniques have recently revealed high prevalences of submicroscopic gametocytemia. Our objective here was to determine the effect of sulfadoxine-pyrimethamine (SP) monotherapy and treatment with SP plus amodiaquine (AQ), SP plus artesunate (AS), and artemether-lumefantrine (AL; Coartem) on submicroscopic gametocytemia and infectiousness. Methods. Kenyan children (n=528) 6 months-10 years of age were randomized to 4 treatment arms. Gametocytemia was determined by both microscopy and Pfs25 RNA-based quantitative nucleic acid sequence-based amplification (Pfs25 QT-NASBA). Transmission was determined by membrane-feeding assays. Results. Gametocyte prevalence, as determined by Pfs25 QT-NASBA, was 89.4% (219/245) at enrollment and decreased after treatment with SP plus AS, SP plus AQ, and AL. Membrane-feeding assays for a group of randomly selected children revealed that the proportion of infectious children was as much as 4-fold higher than expected when based on microscopy. ACT did not significantly reduce the proportion of infectious children but did reduce the proportion of infected mosquitoes. Conclusions. Submicroscopic gametocytemia is common after treatment and contributes considerably to mosquito infection. Our findings should be interpreted in the context of transmission intensity, but the effect of ACT on malaria transmission appears to be moderate and restricted to the duration of gametocyte carriage and the proportion of mosquitoes that are infected by carriers.", "title": "Moderate effect of artemisinin-based combination therapy on transmission of Plasmodium falciparum." }, { "docid": "44048701", "text": "IMPORTANCE The need for surgery for the majority of patients with displaced proximal humeral fractures is unclear, but its use is increasing. \n OBJECTIVE To evaluate the clinical effectiveness of surgical vs nonsurgical treatment for adults with displaced fractures of the proximal humerus involving the surgical neck. \n DESIGN, SETTING, AND PARTICIPANTS A pragmatic, multicenter, parallel-group, randomized clinical trial, the Proximal Fracture of the Humerus Evaluation by Randomization (PROFHER) trial, recruited 250 patients aged 16 years or older (mean age, 66 years [range, 24-92 years]; 192 [77%] were female; and 249 [99.6%] were white) who presented at the orthopedic departments of 32 acute UK National Health Service hospitals between September 2008 and April 2011 within 3 weeks after sustaining a displaced fracture of the proximal humerus involving the surgical neck. Patients were followed up for 2 years (up to April 2013) and 215 had complete follow-up data. The data for 231 patients (114 in surgical group and 117 in nonsurgical group) were included in the primary analysis. \n INTERVENTIONS Fracture fixation or humeral head replacement were performed by surgeons experienced in these techniques. Nonsurgical treatment was sling immobilization. Standardized outpatient and community-based rehabilitation was provided to both groups. \n MAIN OUTCOMES AND MEASURES Primary outcome was the Oxford Shoulder Score (range, 0-48; higher scores indicate better outcomes) assessed during a 2-year period, with assessment and data collection at 6, 12, and 24 months. Sample size was based on a minimal clinically important difference of 5 points for the Oxford Shoulder Score. Secondary outcomes were the Short-Form 12 (SF-12), complications, subsequent therapy, and mortality. \n RESULTS There was no significant mean treatment group difference in the Oxford Shoulder Score averaged over 2 years (39.07 points for the surgical group vs 38.32 points for the nonsurgical group; difference of 0.75 points [95% CI, -1.33 to 2.84 points]; P = .48) or at individual time points. There were also no significant between-group differences over 2 years in the mean SF-12 physical component score (surgical group: 1.77 points higher [95% CI, -0.84 to 4.39 points]; P = .18); the mean SF-12 mental component score (surgical group: 1.28 points lower [95% CI, -3.80 to 1.23 points]; P = .32); complications related to surgery or shoulder fracture (30 patients in surgical group vs 23 patients in nonsurgical group; P = .28), requiring secondary surgery to the shoulder (11 patients in both groups), and increased or new shoulder-related therapy (7 patients vs 4 patients, respectively; P = .58); and mortality (9 patients vs 5 patients; P = .27). Ten medical complications (2 cardiovascular events, 2 respiratory events, 2 gastrointestinal events, and 4 others) occurred in the surgical group during the postoperative hospital stay. \n CONCLUSIONS AND RELEVANCE Among patients with displaced proximal humeral fractures involving the surgical neck, there was no significant difference between surgical treatment compared with nonsurgical treatment in patient-reported clinical outcomes over 2 years following fracture occurrence. These results do not support the trend of increased surgery for patients with displaced fractures of the proximal humerus. \n TRIAL REGISTRATION isrctn.com Identifier: ISRCTN50850043.", "title": "Surgical vs nonsurgical treatment of adults with displaced fractures of the proximal humerus: the PROFHER randomized clinical trial." }, { "docid": "15476777", "text": "BACKGROUND Elderly and frail patients with cancer, although often treated with chemotherapy, are under-represented in clinical trials. We designed FOCUS2 to investigate reduced-dose chemotherapy options and to seek objective predictors of outcome in frail patients with advanced colorectal cancer. \n METHODS We undertook an open, 2 × 2 factorial trial in 61 UK centres for patients with previously untreated advanced colorectal cancer who were considered unfit for full-dose chemotherapy. After comprehensive health assessment (CHA), patients were randomly assigned by minimisation to: 48-h intravenous fluorouracil with levofolinate (group A); oxaliplatin and fluorouracil (group B); capecitabine (group C); or oxaliplatin and capecitabine (group D). Treatment allocation was not masked. Starting doses were 80% of standard doses, with discretionary escalation to full dose after 6 weeks. The two primary outcome measures were: addition of oxaliplatin ([A vs B] + [C vs D]), assessed with progression-free survival (PFS); and substitution of fluorouracil with capecitabine ([A vs C] + [B vs D]), assessed by change from baseline to 12 weeks in global quality of life (QoL). Analysis was by intention to treat. Baseline clinical and CHA data were modelled against outcomes with a novel composite measure, overall treatment utility (OTU). This study is registered, number ISRCTN21221452. \n FINDINGS 459 patients were randomly assigned (115 to each of groups A-C, 114 to group D). Factorial comparison of addition of oxaliplatin versus no addition suggested some improvement in PFS, but the finding was not significant (median 5·8 months [IQR 3·3-7·5] vs 4·5 months [2·8-6·4]; hazard ratio 0·84, 95% CI 0·69-1·01, p=0·07). Replacement of fluorouracil with capecitabine did not improve global QoL: 69 of 124 (56%) patients receiving fluorouracil reported improvement in global QoL compared with 69 of 123 (56%) receiving capecitabine. The risk of having any grade 3 or worse toxic effect was not significantly increased with oxaliplatin (83/219 [38%] vs 70/221 [32%]; p=0·17), but was higher with capecitabine than with fluorouracil (88/222 [40%] vs 65/218 [30%]; p=0·03). In multivariable analysis, fewer baseline symptoms (odds ratio 1·32, 95% CI 1·14-1·52), less widespread disease (1·51, 1·05-2·19), and use of oxaliplatin (0·57, 0·39-0·82) were predictive of better OTU. \n INTERPRETATION FOCUS2 shows that with an appropriate design, including reduced starting doses of chemotherapy, frail and elderly patients can participate in a randomised controlled trial. On balance, a combination including oxaliplatin was preferable to single-agent fluoropyrimidines, although the primary endpoint of PFS was not met. Capecitabine did not improve QoL compared with fluorouracil. Comprehensive baseline assessment holds promise as an objective predictor of treatment benefit. \n FUNDING Cancer Research UK and the Medical Research Council.", "title": "Chemotherapy options in elderly and frail patients with metastatic colorectal cancer (MRC FOCUS2): an open-label, randomised factorial trial" }, { "docid": "10582939", "text": "CONTEXT Antibody-based induction therapy plus calcineurin inhibitors (CNIs) reduce acute rejection rates in kidney recipients; however, opportunistic infections and toxic CNI effects remain challenging. Reportedly, mesenchymal stem cells (MSCs) have successfully treated graft-vs-host disease. \n OBJECTIVE To assess autologous MSCs as replacement of antibody induction for patients with end-stage renal disease who undergo ABO-compatible, cross-match-negative kidney transplants from a living-related donor. \n DESIGN, SETTING, AND PATIENTS One hundred fifty-nine patients were enrolled in this single-site, prospective, open-label, randomized study from February 2008-May 2009, when recruitment was completed. \n INTERVENTION Patients were inoculated with marrow-derived autologous MSC (1-2 x 10(6)/kg) at kidney reperfusion and two weeks later. Fifty-three patients received standard-dose and 52 patients received low-dose CNIs (80% of standard); 51 patients in the control group received anti-IL-2 receptor antibody plus standard-dose CNIs. \n MAIN OUTCOME MEASURES The primary measure was 1-year incidence of acute rejection and renal function (estimated glomerular filtration rate [eGFR]); the secondary measure was patient and graft survival and incidence of adverse events. \n RESULTS Patient and graft survival at 13 to 30 months was similar in all groups. After 6 months, 4 of 53 patients (7.5%) in the autologous MSC plus standard-dose CNI group (95% CI, 0.4%-14.7%; P = .04) and 4 of 52 patients (7.7%) in the low-dose group (95% CI, 0.5%-14.9%; P = .046) compared with 11 of 51 controls (21.6%; 95% CI, 10.5%-32.6%) had biopsy-confirmed acute rejection. None of the patients in either autologous MSC group had glucorticoid-resistant rejection, whereas 4 patients (7.8%) in the control group did (95% CI, 0.6%-15.1%; overall P = .02). Renal function recovered faster among both MSC groups showing increased eGFR levels during the first month after surgery than the control group. Patients receiving standard-dose CNI had a mean difference of 6.2 mL/min per 1.73 m(2) (95% CI, 0.4-11.9; P=.04) and those in the low-dose CNI of 10.0 mL/min per 1.73 m(2) (95% CI, 3.8-16.2; P=.002). Also, during the 1-year follow-up, combined analysis of MSC-treated groups revealed significantly decreased risk of opportunistic infections than the control group (hazard ratio, 0.42; 95% CI, 0.20-0.85, P=.02) CONCLUSION Among patients undergoing renal transplant, the use of autologous MSCs compared with anti-IL-2 receptor antibody induction therapy resulted in lower incidence of acute rejection, decreased risk of opportunistic infection, and better estimated renal function at 1 year. \n TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00658073.", "title": "Induction therapy with autologous mesenchymal stem cells in living-related kidney transplants: a randomized controlled trial." } ]

[ { "docid": "14376683", "text": "The non-enveloped bacilliform viruses are the second group of plant viruses known to possess a genome consisting of circular double-stranded DNA. We have characterized the viral transcript and determined the complete sequence of the genome of Commelina mellow mottle virus (CoYMV), a member of this group. Analysis of the viral transcript indicates that the virus encodes a single terminally-redundant genome-length plus 120 nucleotide transcript. A fraction of the transcripts is polyadenylated, although the majority of the transcript is not polyadenylated. Analysis of the genome sequence indicates that the genome is 7489 bp in size and that the transcribed strand contains three open reading frames capable of encoding proteins of 23, 15 and 216 kd. The function of the 25 and 15 kd proteins is unknown. Similarities between the 216 kd polypeptide and the cauliflower mosaic virus coat protein and protease/reverse transcriptase polyprotein suggest that the 216 kd polypeptide is a polyprotein that is proteolytically processed to yield the virion coat protein, a protease, and replicase (reverse transcriptase and ribonuclease H). Each strand of the CoYMV genome is interrupted by site-specific discontinuities. The locations of the 5'-ends of these discontinuities, and the presence and location of a region on the CoYMV transcript capable of annealing with the 3'-end of cytosolic initiator methionine tRNA are consistent with replication by reverse transcription. We have demonstrated that a construct containing 1.3 CoYMV genomes is infective when introduced into Commelina diffusa, the host for CoYMV, using Agrobacterium-mediated infection.", "title": "Properties of Commelina yellow mottle virus's complete DNA sequence, genomic discontinuities and transcript suggest that it is a pararetrovirus." } ]

[ { "docid": "37677954", "text": "A new badnavirus was discovered from pagoda trees showing yellow mosaic symptoms on the leaves by high throughput sequencing of small RNAs. The complete genome of this virus was determined to comprise 7424 nucleotides, and the virus shared 40.4-45.1% identity with that of other badnaviruses. The genome encodes five open reading frames (ORFs) on the plus strand, which includes three conserved badnaviral ORFs. These results suggest that this virus is a new member of the genus Badnavirus in the family Caulimoviridae. The virus is tentatively named pagoda yellow mosaic associated virus (PYMAV). Phylogenetic analysis suggested that this virus together with gooseberry vein banding virus (GVBV) and grapevine vein-clearing virus (GVCV) forms a separate group that is distinct two other well characterized badnaviral groups. Additionally, the viral derived small RNA (vsRNA) profile of PYMAV was analyzed and compared with that of viruses within the same family. Results showed that the most abundant PYMAV vsRNAs were 21-nt, whereas other viruses in the same family have a predominance of 22- or 24-nt vsRNA. The percentage of sense PYMAV vsRNA was almost equal to that of antisense vsRNA, whereas vsRNAs of other viruses in the family display preferences toward the sense strand of their genome. Furthermore, PYMAV vsRNAs were symmetrically distributed along the genome with no obvious vsRNA generating hotspots.", "title": "Characterization of complete genome and small RNA profile of pagoda yellow mosaic associated virus, a novel badnavirus in China." }, { "docid": "83667891", "text": "Sri Lankan black pepper with symptoms of yellow mottle disease contained a mixture of viruses: Piper yellow mottle virus (PYMV) particles (30 × 130 nm), Cucumber mosaic virus (CMV, 30 nm diameter isometric particles), and unidentified, isometric virus-like particles (30 nm diameter). An effective purification procedure is described for PYMV. Immunosorbent and conventional electron microscopy successfully detected badnavirus particles only when at least partially purified extracts were used. PYMV was confirmed as the cause of the disease, with the other two viruses apparently playing no part in producing symptoms. PYMV was transmitted by grafting, by the insect vectors citrus mealy bug (Planococcus citri) and black pepper lace bug (Diconocoris distanti), but not by mechanical inoculation or through seeds. The CMV isolate was transmitted to indicator plants by mechanical inoculation and by the vector Aphis gossypii, but not by Myzus persicae; but neither mechanical nor insect transmission of CMV to black pepper was successful. A sensitive polymerase chain reaction assay was developed to detect PYMV in black pepper.", "title": "Identification and transmission of Piper yellow mottle virus and Cucumber mosaic virus infecting black pepper (Piper nigrum) in Sri Lanka" }, { "docid": "21230110", "text": "Taro bacilliform virus (TaBV) is a pararetrovirus of the genus Badnavirus which infects the monocotyledonous plant, taro (Colocasia esculenta). A region of the TaBV genome spanning nucleotides 6,281 to 12 (T1200), including the 3′ end of open reading frame 3 (ORF 3) and the intergenic region to the end of the tRNAmet-binding site, was tested for promoter activity along with four different 5′ deletion fragments (T600, T500, T250 and T100). In transient assays, only the T1200, T600, T500 fragments were shown to have promoter activity in taro leaf, banana suspension cells and tobacco callus. When these three promoters were evaluated in stably transformed, in vitro-grown transgenic banana and tobacco plants, all were found to drive near-constitutive expression of either the green fluorescent protein or β-glucuronidase (GUS) reporter gene in the stem (or pseudostem), leaves and roots, with strongest expression observed in the vascular tissue. In transgenic banana leaves, the T600 promoter directed four-fold greater GUS activity than that of the T1200, T500 and the maize polyubiquitin-1 promoters. In transgenic tobacco leaves, the levels of GUS expression directed by the three promoters was between four- and ten-fold lower than that of the double Cauliflower mosaic virus 35S promoter. These results indicate that the TaBV-derived promoters may be useful for the high-level constitutive expression of transgenes in either monocotyledonous or dicotyledonous species.", "title": "A promoter derived from taro bacilliform badnavirus drives strong expression in transgenic banana and tobacco plants" }, { "docid": "29107180", "text": "The structure of the human gene encoding the double-stranded RNA (dsRNA) adenosine deaminase (DRADA) was characterized. This nuclear localized enzyme is involved in the RNA editing required for the expression of certain subtypes of glutamate-gated ion channel subunits. The DRADA gene span 30 kb pairs and harbors 15 exons. The transcription of the DRADA gene driven by the putative promoter region, which contains no typical TATA or CCAAT box-like sequences, is initiated at multiple sites, 164 to 216 nucleotides upstream of the translation initiation codon. The three dsRNA binding motifs (DRBM), 70 amino acid residues long, are each encoded by two exons plus an intervening sequence that interrupts the motif at the identical amino acid position. This finding is consistent with the notion that the dsRNA binding domains may be composed of two separate functional subdomains. Fluorescent in situ hybridization localized the DRADA gene on the long arm chromosome 1, region q21. The gene structure and sequence information reported in this study will facilitate the investigation of involvement of DRADA in hereditary diseases that may be the result of malfunction of glutamate-gated ion channels.", "title": "Genomic organization and chromosomal location of the human dsRNA adenosine deaminase gene: the enzyme for glutamate-activated ion channel RNA editing." }, { "docid": "8979167", "text": "An open reading frame (ORF) with homology to interleukin-10 (IL-10) has been identified in rhesus cytomegalovirus (RhCMV). The IL-10-like protein is generated from a multispliced, polyadenylated early gene transcript encompassing part of the corresponding UL111A ORF of human CMV (HCMV). Immunological analyses confirm expression of the IL-10-like protein both in tissue culture and in RhCMV-infected rhesus macaques. Conserved ORFs were subsequently identified in human, baboon, and African green monkey CMV, and a fully processed transcript has been mapped in fibroblasts infected with the Towne strain of HCMV. The conservation of this previously unrecognized ORF suggests that the protein may play an essential role in primate CMV persistence and pathogenesis.", "title": "Primate cytomegaloviruses encode and express an IL-10-like protein." }, { "docid": "1225513", "text": "UNLABELLED Two-component systems (TCS) comprise histidine kinases and their cognate response regulators and allow bacteria to sense and respond to a wide variety of signals. Histidine kinases (HKs) phosphorylate and dephosphorylate their cognate response regulators (RRs) in response to stimuli. In general, these reactions appear to be highly specific and require an appropriate association between the HK and RR proteins. The Myxococcus xanthus genome encodes one of the largest repertoires of signaling proteins in bacteria (685 open reading frames [ORFs]), including at least 127 HKs and at least 143 RRs. Of these, 27 are bona fide NtrC-family response regulators, 21 of which are encoded adjacent to their predicted cognate kinases. Using system-wide profiling methods, we determined that the HK-NtrC RR pairs display a kinetic preference during both phosphotransfer and phosphatase functions, thereby defining cognate signaling systems in M. xanthus. Isothermal titration calorimetry measurements indicated that cognate HK-RR pairs interact with dissociation constants (Kd) of approximately 1 µM, while noncognate pairs had no measurable binding. Lastly, a chimera generated between the histidine kinase, CrdS, and HK1190 revealed that residues conferring phosphotransfer and phosphatase specificity dictate binding affinity, thereby establishing discrete protein-protein interactions which prevent cross talk. The data indicate that binding affinity is a critical parameter governing system-wide signaling fidelity for bacterial signal transduction proteins. IMPORTANCE Using in vitro phosphotransfer and phosphatase profiling assays and isothermal titration calorimetry, we have taken a system-wide approach to demonstrate specificity for a family of two-component signaling proteins in Myxococcus xanthus. Our results demonstrate that previously identified specificity residues dictate binding affinity and that phosphatase specificity follows phosphotransfer specificity for cognate HK-RR pairs. The data indicate that preferential binding affinity is the basis for signaling fidelity in bacterial two-component systems.", "title": "Specificity Residues Determine Binding Affinity for Two-Component Signal Transduction Systems" }, { "docid": "35711485", "text": "Banana streak disease is caused by several distinct badnavirus species, one of which is Banana streak Obino l'Ewai virus. Banana streak Obino l'Ewai virus has severely hindered international banana (Musa spp.) breeding programmes, as new hybrids are frequently infected with this virus, curtailing any further exploitation. This infection is thought to arise from viral DNA integrated in the nuclear genome of Musa balbisiana (B genome), one of the wild species contributing to many of the banana cultivars currently grown. In order to determine whether the DNA of other badnavirus species is integrated in the Musa genome, PCR-amplified DNA fragments from Musa acuminata, M. balbisiana and Musa schizocarpa, as well as cultivars 'Obino l'Ewai' and 'Klue Tiparot', were cloned. In total, 103 clones were sequenced and all had similarity to open reading frame III in the badnavirus genome, although there was remarkable variation, with 36 distinct sequences being recognized with less than 85 % nucleotide identity to each other. There was no commonality in the sequences amplified from M. acuminata and M. balbisiana, suggesting that integration occurred following the separation of these species. Analysis of rates of non-synonymous and synonymous substitution suggested that the integrated sequences evolved under a high degree of selective constraint as might be expected for a living badnavirus, and that each distinct sequence resulted from an independent integration event.", "title": "Banana contains a diverse array of endogenous badnaviruses." }, { "docid": "7451018", "text": "Cancer has been recognized for thousands of years. Egyptians believed that cancer occurred at the will of the gods. Hippocrates believed human disease resulted from an imbalance of the four humors: blood, phlegm, yellow bile, and black bile with cancer being caused by excess black bile. The lymph theory of cancer replaced the humoral theory and the blastema theory replaced the lymph theory. Rudolph Virchow was the first to recognize that cancer cells like all cells came from other cells and believed chronic irritation caused cancer. At the same time there was a belief that trauma caused cancer, though it never evolved after many experiments inducing trauma. The birth of virology occurred in 1892 when Dimitri Ivanofsky demonstrated that diseased tobacco plants remained infective after filtering their sap through a filter that trapped bacteria. Martinus Beijerinck would call the tiny infective agent a virus and both Dimitri Ivanofsky and Marinus Beijerinck would become the fathers of virology. Not to long thereafter, Payton Rous founded the field of tumor virology in 1911 with his discovery of a transmittable sarcoma of chickens by what would come to be called Rous sarcoma virus or RSV for short. The first identified human tumor virus was the Epstein-Barr virus (EBV), named after Tony Epstein and Yvonne Barr who visualized the virus particles in Burkitt's lymphoma cells by electron microscopy in 1965. Since that time, many viruses have been associated with carcinogenesis including the most studied, human papilloma virus associated with cervical carcinoma, many other anogenital carcinomas, and oropharyngeal carcinoma. The World Health Organization currently estimates that approximately 22% of worldwide cancers are attributable to infectious etiologies, of which viral etiologies is estimated at 15-20%. The field of tumor virology/viral carcinogenesis has not only identified viruses as etiologic agents of human cancers, but has also given molecular insights to all human cancers including the oncogene activation and tumor suppressor gene inactivation.", "title": "Viral Carcinogenesis." }, { "docid": "18914652", "text": "Notwithstanding the well-characterised roles of a number of oncogenes in neoplastic transformation, microRNAs (miRNAs) are increasingly implicated in several human cancers. Discovery of miRNAs in several oncogenic herpesviruses such as KSHV has further highlighted the potential of virus-encoded miRNAs to contribute to their oncogenic capabilities. Nevertheless, despite the identification of several possible cancer-related genes as their targets, the direct in vivo role of virus-encoded miRNAs in neoplastic diseases such as those induced by KSHV is difficult to demonstrate in the absence of suitable models. However, excellent natural disease models of rapid-onset Marek's disease (MD) lymphomas in chickens allow examination of the oncogenic potential of virus-encoded miRNAs. Using viruses modified by reverse genetics of the infectious BAC clone of the oncogenic RB-1B strain of MDV, we show that the deletion of the six-miRNA cluster 1 from the viral genome abolished the oncogenicity of the virus. This loss of oncogenicity appeared to be primarily due to the single miRNA within the cluster, miR-M4, the ortholog of cellular miR-155, since its deletion or a 2-nucleotide mutation within its seed region was sufficient to inhibit the induction of lymphomas. The definitive role of this miR-155 ortholog in oncogenicity was further confirmed by the rescue of oncogenic phenotype by revertant viruses that expressed either the miR-M4 or the cellular homolog gga-miR-155. This is the first demonstration of the direct in vivo role of a virus-encoded miRNA in inducing tumors in a natural infection model. Furthermore, the use of viruses deleted in miRNAs as effective vaccines against virulent MDV challenge, enables the prospects of generating genetically defined attenuated vaccines.", "title": "Critical Role of the Virus-Encoded MicroRNA-155 Ortholog in the Induction of Marek's Disease Lymphomas" }, { "docid": "13614794", "text": "The cyclin-dependent kinase Cdk2 associates with cyclins A, D, and E and has been implicated in the control of the G1 to S phase transition in mammals. To identify potential Cdk2 regulators, we have employed an improved two-hybrid system to isolate human genes encoding Cdk-interacting proteins (Cips). CIP1 encodes a novel 21 kd protein that is found in cyclin A, cyclin D1, cyclin E, and Cdk2 immunoprecipitates. p21CIP1 is a potent, tight-binding inhibitor of Cdks and can inhibit the phosphorylation of Rb by cyclin A-Cdk2, cyclin E-Cdk2, cyclin D1-Cdk4, and cyclin D2-Cdk4 complexes. Cotransfection experiments indicate that CIP1 and SV40 T antigen function in a mutually antagonistic manner to control cell cycle progression.", "title": "The p21 Cdk-interacting protein Cip1 is a potent inhibitor of G1 cyclin-dependent kinases." }, { "docid": "7059897", "text": "The variable domain of an immunoglobulin (IG) sequence is encoded by multiple genes, including the variable (V) gene, the diversity (D) gene and the joining (J) gene. Analysis of IG sequences typically requires identification of each gene, as well as a comparison of sequence variations in the context of defined regions. General purpose tools, such as the BLAST program, have only limited use for such tasks, as the rearranged nature of an IG sequence and the variable length of each gene requires multiple rounds of BLAST searches for a single IG sequence. Additionally, manual assembly of different genes is difficult and error-prone. To address these issues and to facilitate other common tasks in analysing IG sequences, we have developed the sequence analysis tool IgBLAST (http://www.ncbi.nlm.nih.gov/igblast/). With this tool, users can view the matches to the germline V, D and J genes, details at rearrangement junctions, the delineation of IG V domain framework regions and complementarity determining regions. IgBLAST has the capability to analyse nucleotide and protein sequences and can process sequences in batches. Furthermore, IgBLAST allows searches against the germline gene databases and other sequence databases simultaneously to minimize the chance of missing possibly the best matching germline V gene.", "title": "IgBLAST: an immunoglobulin variable domain sequence analysis tool" }, { "docid": "4373445", "text": "The GTPases Rac1, RhoA and Cdc42 act together to control cytoskeleton dynamics. Recent biosensor studies have shown that all three GTPases are activated at the front of migrating cells, and biochemical evidence suggests that they may regulate one another: Cdc42 can activate Rac1 (ref. 8), and Rac1 and RhoA are mutually inhibitory. However, their spatiotemporal coordination, at the seconds and single-micrometre dimensions typical of individual protrusion events, remains unknown. Here we examine GTPase coordination in mouse embryonic fibroblasts both through simultaneous visualization of two GTPase biosensors and using a 'computational multiplexing' approach capable of defining the relationships between multiple protein activities visualized in separate experiments. We found that RhoA is activated at the cell edge synchronous with edge advancement, whereas Cdc42 and Rac1 are activated 2 micro-m behind the edge with a delay of 40 s. This indicates that Rac1 and RhoA operate antagonistically through spatial separation and precise timing, and that RhoA has a role in the initial events of protrusion, whereas Rac1 and Cdc42 activate pathways implicated in reinforcement and stabilization of newly expanded protrusions.", "title": "Coordination of Rho GTPase activities during cell protrusion" }, { "docid": "46193478", "text": "Abstract A simple technique has been developed for the study of the external form and structure of virus particles. High contrast with good preservation is obtained by mixing virus preparations with 1% phosphotungstic acid adjusted to pH 7.5 and spraying directly onto electron microscope supporting films made from evaporated carbon. The application of the technique to tobacco mosaic virus and turnip yellow mosaic virus is described. Structural details suggested by X-ray diffraction methods have been resolved.", "title": "A negative staining method for high resolution electron microscopy of viruses." }, { "docid": "991139", "text": "The CC genotype of the interleukin (IL)-28B.rs12979860 gene has been associated with spontaneous hepatitis C virus (HCV) clearance and treatment response. The distribution and correlation of an IL28B.rs12979860 single-nucleotide polymorphism (SNP) with HCV-specific cell-mediated immune (CMI) responses among Egyptian healthcare workers (HCWs) is not known. We determined this relationship in 402 HCWs who serve a patient cohort with ~85 % HCV prevalence. We enrolled 402 HCWs in four groups: group 1 (n = 258), seronegative aviremic subjects; group 2 (n = 25), seronegative viremic subjects; group 3 (n = 41), subjects with spontaneously resolved HCV infection; and group 4 (n = 78), chronic HCV patients. All subjects were tested for an HCV-specific CMI response using an ex-vivo interferon-gamma (IFNγ) ELISpot assay with nine HCV genotype-4a overlapping 15-mer peptide pools corresponding to all of the HCV proteins. All subjects were tested for IL28B.rs12979860 SNP by real-time PCR. An HCV-specific CMI was demonstrated in ~27 % of the seronegative aviremic HCWs (group 1), suggesting clearance of infection after low-level exposure to HCV. The frequency of IL28B.rs12979860 C allele homozygosity in the four groups was 49 %, 48 %, 49 %, and 23 %, while that of the T allele was 14 %, 16 %, 12 and 19 %, respectively, suggesting differential distributions among subjects with different HCV status. As reported, IL28B.rs12979860 predicted the outcome of HCV infection (p < 0.05), but we did not find any relationship between the IL28B genotypes and the outcome of HCV-specific CMI responses in the four groups (p > 0.05). The data show differential IL28B.rs12979860 genotype distribution among Egyptian HCWs with different HCV status and could not predict the outcome of HCV-specific CMI responses.", "title": "Differential distribution of IL28B.rs12979860 single-nucleotide polymorphism among Egyptian healthcare workers with and without a hepatitis C virus-specific cellular immune response" }, { "docid": "4387484", "text": "The Kaposi's sarcoma-associated herpesvirus (KSHV/HHV8) is a gamma-2 herpesvirus that is implicated in the pathogenesis of Kaposi's sarcoma and of primary effusion B-cell lymphomas (PELs). KSHV infects malignant and progenitor cells of Kaposi's sarcoma and PEL, it encodes putative oncogenes and genes that may cause Kaposi's sarcoma pathogenesis by stimulating angiogenesis. The G-protein-coupled receptor encoded by an open reading frame (ORF 74) of KSHV is expressed in Kaposi's sarcoma lesions and in PEL and stimulates signalling pathways linked to cell proliferation in a constitutive (agonist-independent) way. Here we show that signalling by this KSHV G-protein-coupled receptor leads to cell transformation and tumorigenicity, and induces a switch to an angiogenic phenotype mediated by vascular endothelial growth factor, an angiogenesis and Kaposi's-spindle-cell growth factor. We find that this receptor can activate two protein kinases, JNK/SAPK and p38MAPK, by triggering signalling cascades like those induced by inflammatory cytokines that are angiogenesis activators and mitogens for Kaposi's sarcoma cells and B cells. We conclude that the KSHV G-protein-coupled receptor is a viral oncogene that can exploit cell signalling pathways to induce transformation and angiogenesis in KSHV-mediated oncogenesis.", "title": "G-protein-coupled receptor of Kaposi's sarcoma-associated herpesvirus is a viral oncogene and angiogenesis activator." }, { "docid": "87986426", "text": "Sugarcane bacilliform virus(SCBV) was detected by PCR from sugarcane showing chlorosis and mottle symptom from Kaiyuan,Yunnan Province. Part sequence of replicase gene of the isolate SCBV-Kaiyuan was determined. Sequence analysis indicated that the 589 bp of SCBV-Kaiyuan shared identities of 73.2%-74.0% and 83.1%-84.1% at nucleotide and amino acid levels with SCBV-Australia respectively,66.7%-68.4% and 65.6%-67.7% with SCBV-Morocco. The quality and yield of the sugarcane infected with SCBV-Kaiyuan was also investigated. The juice extraction,sucrose content,gravity purity and average stalk weight were decreased 1.55%,1.24%,2.22% and 0.26 kg in plants infected with SCBV-Kaiyuan,but reducing sugar was increased by 0.21% in infected plants.", "title": "Detection of Sugarcane bacilliform virus isolate and its influence on yield and quality of cane in Yunnan" }, { "docid": "37450671", "text": "The protein component of Alzheimer's disease amyloid [neurofibrillary tangles (NFT), amyloid plaque core and congophilic angiopathy] is an aggregated polypeptide with a subunit mass of 4 kd (the A4 monomer). Based on the degree of N-terminal heterogeneity, the amyloid is first deposited in the neuron, and later in the extracellular space. Using antisera raised against synthetic peptides, we show that the N terminus of A4 (residues 1-11) contains an epitope for neurofibrillary tangles, and the inner region of the molecule (residues 11-23) contains an epitope for plaque cores and vascular amyloid. The non-protein component of the amyloid (aluminum silicate) may form the basis for the deposition or amplification (possible self-replication) of the aggregated amyloid protein. The amyloid of Alzheimer's disease is similar in subunit size, composition but not sequence to the scrapie-associated fibril and its constituent polypeptides. The sequence and composition of NFT are not homologous to those of any of the known components of normal neurofilaments.", "title": "Neuronal origin of a cerebral amyloid: neurofibrillary tangles of Alzheimer's disease contain the same protein as the amyloid of plaque cores and blood vessels." }, { "docid": "1333643", "text": "Multicellular eukaryotes produce small RNA molecules (approximately 21–24 nucleotides) of two general types, microRNA (miRNA) and short interfering RNA (siRNA). They collectively function as sequence-specific guides to silence or regulate genes, transposons, and viruses and to modify chromatin and genome structure. Formation or activity of small RNAs requires factors belonging to gene families that encode DICER (or DICER-LIKE [DCL]) and ARGONAUTE proteins and, in the case of some siRNAs, RNA-dependent RNA polymerase (RDR) proteins. Unlike many animals, plants encode multiple DCL and RDR proteins. Using a series of insertion mutants of Arabidopsis thaliana, unique functions for three DCL proteins in miRNA (DCL1), endogenous siRNA (DCL3), and viral siRNA (DCL2) biogenesis were identified. One RDR protein (RDR2) was required for all endogenous siRNAs analyzed. The loss of endogenous siRNA in dcl3 and rdr2 mutants was associated with loss of heterochromatic marks and increased transcript accumulation at some loci. Defects in siRNA-generation activity in response to turnip crinkle virus in dcl2 mutant plants correlated with increased virus susceptibility. We conclude that proliferation and diversification of DCL and RDR genes during evolution of plants contributed to specialization of small RNA-directed pathways for development, chromatin structure, and defense.", "title": "Genetic and Functional Diversification of Small RNA Pathways in Plants" }, { "docid": "3765739", "text": "Resistance to apoptosis is an important component of the overall mechanism which drives the tumorigenic process. EBV is a ubiquitous human gamma-herpesvirus which preferentially establishes latent infection in viral infected B-lymphocytes. EBNA1 is typically expressed in most forms of EBV-positive malignancies and is important for replication of the latent episome in concert with replication of the host cells. Here, we investigate the effects of EBNA1 on survivin up-regulation in EBV-infected human B-lymphoma cells. We present evidence which demonstrates that EBNA1 forms a complex with Sp1 or Sp1-like proteins bound to their cis-element at the survivin promoter. This enhances the activity of the complex and up-regulates survivin. Knockdown of survivin and EBNA1 showed enhanced apoptosis in infected cells and thus supports a role for EBNA1 in suppressing apoptosis in EBV-infected cells. Here, we suggest that EBV encoded EBNA1 can contribute to the oncogenic process by up-regulating the apoptosis suppressor protein, survivin in EBV-associated B-lymphoma cells.", "title": "Epstein-Barr Virus nuclear antigen 1 (EBNA1) confers resistance to apoptosis in EBV-positive B-lymphoma cells through up-regulation of survivin." } ]

[ { "docid": "14376683", "text": "The non-enveloped bacilliform viruses are the second group of plant viruses known to possess a genome consisting of circular double-stranded DNA. We have characterized the viral transcript and determined the complete sequence of the genome of Commelina mellow mottle virus (CoYMV), a member of this group. Analysis of the viral transcript indicates that the virus encodes a single terminally-redundant genome-length plus 120 nucleotide transcript. A fraction of the transcripts is polyadenylated, although the majority of the transcript is not polyadenylated. Analysis of the genome sequence indicates that the genome is 7489 bp in size and that the transcribed strand contains three open reading frames capable of encoding proteins of 23, 15 and 216 kd. The function of the 25 and 15 kd proteins is unknown. Similarities between the 216 kd polypeptide and the cauliflower mosaic virus coat protein and protease/reverse transcriptase polyprotein suggest that the 216 kd polypeptide is a polyprotein that is proteolytically processed to yield the virion coat protein, a protease, and replicase (reverse transcriptase and ribonuclease H). Each strand of the CoYMV genome is interrupted by site-specific discontinuities. The locations of the 5'-ends of these discontinuities, and the presence and location of a region on the CoYMV transcript capable of annealing with the 3'-end of cytosolic initiator methionine tRNA are consistent with replication by reverse transcription. We have demonstrated that a construct containing 1.3 CoYMV genomes is infective when introduced into Commelina diffusa, the host for CoYMV, using Agrobacterium-mediated infection.", "title": "Properties of Commelina yellow mottle virus's complete DNA sequence, genomic discontinuities and transcript suggest that it is a pararetrovirus." } ]

[ { "docid": "83667891", "text": "Sri Lankan black pepper with symptoms of yellow mottle disease contained a mixture of viruses: Piper yellow mottle virus (PYMV) particles (30 × 130 nm), Cucumber mosaic virus (CMV, 30 nm diameter isometric particles), and unidentified, isometric virus-like particles (30 nm diameter). An effective purification procedure is described for PYMV. Immunosorbent and conventional electron microscopy successfully detected badnavirus particles only when at least partially purified extracts were used. PYMV was confirmed as the cause of the disease, with the other two viruses apparently playing no part in producing symptoms. PYMV was transmitted by grafting, by the insect vectors citrus mealy bug (Planococcus citri) and black pepper lace bug (Diconocoris distanti), but not by mechanical inoculation or through seeds. The CMV isolate was transmitted to indicator plants by mechanical inoculation and by the vector Aphis gossypii, but not by Myzus persicae; but neither mechanical nor insect transmission of CMV to black pepper was successful. A sensitive polymerase chain reaction assay was developed to detect PYMV in black pepper.", "title": "Identification and transmission of Piper yellow mottle virus and Cucumber mosaic virus infecting black pepper (Piper nigrum) in Sri Lanka" }, { "docid": "37677954", "text": "A new badnavirus was discovered from pagoda trees showing yellow mosaic symptoms on the leaves by high throughput sequencing of small RNAs. The complete genome of this virus was determined to comprise 7424 nucleotides, and the virus shared 40.4-45.1% identity with that of other badnaviruses. The genome encodes five open reading frames (ORFs) on the plus strand, which includes three conserved badnaviral ORFs. These results suggest that this virus is a new member of the genus Badnavirus in the family Caulimoviridae. The virus is tentatively named pagoda yellow mosaic associated virus (PYMAV). Phylogenetic analysis suggested that this virus together with gooseberry vein banding virus (GVBV) and grapevine vein-clearing virus (GVCV) forms a separate group that is distinct two other well characterized badnaviral groups. Additionally, the viral derived small RNA (vsRNA) profile of PYMAV was analyzed and compared with that of viruses within the same family. Results showed that the most abundant PYMAV vsRNAs were 21-nt, whereas other viruses in the same family have a predominance of 22- or 24-nt vsRNA. The percentage of sense PYMAV vsRNA was almost equal to that of antisense vsRNA, whereas vsRNAs of other viruses in the family display preferences toward the sense strand of their genome. Furthermore, PYMAV vsRNAs were symmetrically distributed along the genome with no obvious vsRNA generating hotspots.", "title": "Characterization of complete genome and small RNA profile of pagoda yellow mosaic associated virus, a novel badnavirus in China." }, { "docid": "87986426", "text": "Sugarcane bacilliform virus(SCBV) was detected by PCR from sugarcane showing chlorosis and mottle symptom from Kaiyuan,Yunnan Province. Part sequence of replicase gene of the isolate SCBV-Kaiyuan was determined. Sequence analysis indicated that the 589 bp of SCBV-Kaiyuan shared identities of 73.2%-74.0% and 83.1%-84.1% at nucleotide and amino acid levels with SCBV-Australia respectively,66.7%-68.4% and 65.6%-67.7% with SCBV-Morocco. The quality and yield of the sugarcane infected with SCBV-Kaiyuan was also investigated. The juice extraction,sucrose content,gravity purity and average stalk weight were decreased 1.55%,1.24%,2.22% and 0.26 kg in plants infected with SCBV-Kaiyuan,but reducing sugar was increased by 0.21% in infected plants.", "title": "Detection of Sugarcane bacilliform virus isolate and its influence on yield and quality of cane in Yunnan" }, { "docid": "1383826", "text": "RNA molecules fulfill a diverse set of biological functions within cells, from the transfer of genetic information from DNA to protein, to enzymatic catalysis. Reflecting this range of roles, simple linear strings of RNA—made up of uracil, guanine, cytosine, and adenine—form a variety of complex three-dimensional structures. Just as proteins form distinct structural motifs such as zinc fingers and beta barrels, certain structures are also commonly adopted by RNA molecules. Among the most prevalent RNA structures is a motif known as the pseudoknot. First recognized in the turnip yellow mosaic virus [1], a pseudoknot is an RNA structure that is minimally composed of two helical segments connected by single-stranded regions or loops (Figure 1). Although several distinct folding topologies of pseudoknots exist, the best characterized is the H type. In the H-type fold, the bases in the loop of a hairpin form intramolecular pairs with bases outside of the stem (Figure 1A and ​and1B).1B). This causes the formation of a second stem and loop, resulting in a pseudoknot with two stems and two loops (Figure 1C). The two stems are able to stack on top of each other to form a quasi-continuous helix with one continuous and one discontinuous strand. The single-stranded loop regions often interact with the adjacent stems (loop 1–stem 2 or loop 2–stem 1) to form hydrogen bonds and to participate in the overall structure of the molecule. Hence, this relatively simple fold can yield very complex and stable RNA structures. Due to variation of the lengths of the loops and stems, as well as the types of interactions between them, pseudoknots represent a structurally diverse group. It is fitting that they play a variety of diverse roles in biology. These roles include forming the catalytic core of various ribozymes [2,3], self-splicing introns [4], and telomerase [5]. Additionally, pseudoknots play critical roles in altering gene expression by inducing ribosomal frameshifting in many viruses [6–9].", "title": "Pseudoknots: RNA Structures with Diverse Functions" }, { "docid": "46193478", "text": "Abstract A simple technique has been developed for the study of the external form and structure of virus particles. High contrast with good preservation is obtained by mixing virus preparations with 1% phosphotungstic acid adjusted to pH 7.5 and spraying directly onto electron microscope supporting films made from evaporated carbon. The application of the technique to tobacco mosaic virus and turnip yellow mosaic virus is described. Structural details suggested by X-ray diffraction methods have been resolved.", "title": "A negative staining method for high resolution electron microscopy of viruses." }, { "docid": "7451018", "text": "Cancer has been recognized for thousands of years. Egyptians believed that cancer occurred at the will of the gods. Hippocrates believed human disease resulted from an imbalance of the four humors: blood, phlegm, yellow bile, and black bile with cancer being caused by excess black bile. The lymph theory of cancer replaced the humoral theory and the blastema theory replaced the lymph theory. Rudolph Virchow was the first to recognize that cancer cells like all cells came from other cells and believed chronic irritation caused cancer. At the same time there was a belief that trauma caused cancer, though it never evolved after many experiments inducing trauma. The birth of virology occurred in 1892 when Dimitri Ivanofsky demonstrated that diseased tobacco plants remained infective after filtering their sap through a filter that trapped bacteria. Martinus Beijerinck would call the tiny infective agent a virus and both Dimitri Ivanofsky and Marinus Beijerinck would become the fathers of virology. Not to long thereafter, Payton Rous founded the field of tumor virology in 1911 with his discovery of a transmittable sarcoma of chickens by what would come to be called Rous sarcoma virus or RSV for short. The first identified human tumor virus was the Epstein-Barr virus (EBV), named after Tony Epstein and Yvonne Barr who visualized the virus particles in Burkitt's lymphoma cells by electron microscopy in 1965. Since that time, many viruses have been associated with carcinogenesis including the most studied, human papilloma virus associated with cervical carcinoma, many other anogenital carcinomas, and oropharyngeal carcinoma. The World Health Organization currently estimates that approximately 22% of worldwide cancers are attributable to infectious etiologies, of which viral etiologies is estimated at 15-20%. The field of tumor virology/viral carcinogenesis has not only identified viruses as etiologic agents of human cancers, but has also given molecular insights to all human cancers including the oncogene activation and tumor suppressor gene inactivation.", "title": "Viral Carcinogenesis." }, { "docid": "253672", "text": "OBJECTIVE To determine whether the novel avian influenza H7N9 virus can transmit from person to person and its efficiency. \n DESIGN Epidemiological investigations conducted after a family cluster of two patients with avian H7N9 in March 2013. \n SETTING Wuxi, Eastern China. \n PARTICIPANTS Two patients, their close contacts, and relevant environments. Samples from the patients and environments were collected and tested by real time reverse transcriptase-polymerase chain reaction (rRT-PCR), viral culture, and haemagglutination inhibition assay. Any contacts who became ill had samples tested for avian H7N9 by rRT-PCR. Paired serum samples were obtained from contacts for serological testing by haemagglutination inhibition assays. \n MAIN OUTCOMES MEASURES Clinical data, history of exposure before the onset of illnesses, and results of laboratory testing of pathogens and further analysis of sequences and phylogenetic tree to isolated strains. \n RESULTS The index patient became ill five to six days after his last exposure to poultry. The second patient, his daughter aged 32, who provided unprotected bedside care in the hospital, had no known exposure to poultry. She developed symptoms six days after her last contact with her father. Two strains were isolated successfully from the two patients. Genome sequence and analyses of phylogenetic trees showed that both viruses were almost genetically identical. Forty three close contacts of both patients were identified. One had mild illness but had negative results for avian H7N9 by rRT-PCR. All 43 close contacts tested negative for haemagglutination inhibition antibodies specific for avian H7N9. \n CONCLUSIONS The infection of the daughter probably resulted from contact with her father (the index patient) during unprotected exposure, suggesting that in this cluster the virus was able to transmit from person to person. The transmissibility was limited and non-sustainable.", "title": "Probable person to person transmission of novel avian influenza A (H7N9) virus in Eastern China, 2013: epidemiological investigation" }, { "docid": "11359243", "text": "Altered DNA methylation occurs ubiquitously in human cancer from the earliest measurable stages. A cogent approach to understanding the mechanism and timing of altered DNA methylation is to analyze it in the context of carcinogenesis by a defined agent. Epstein-Barr virus (EBV) is a human oncogenic herpesvirus associated with lymphoma and nasopharyngeal carcinoma, but also used commonly in the laboratory to immortalize human B-cells in culture. Here we have performed whole-genome bisulfite sequencing of normal B-cells, activated B-cells, and EBV-immortalized B-cells from the same three individuals, in order to identify the impact of transformation on the methylome. Surprisingly, large-scale hypomethylated blocks comprising two-thirds of the genome were induced by EBV immortalization but not by B-cell activation per se. These regions largely corresponded to hypomethylated blocks that we have observed in human cancer, and they were associated with gene-expression hypervariability, similar to human cancer, and consistent with a model of epigenomic change promoting tumor cell heterogeneity. We also describe small-scale changes in DNA methylation near CpG islands. These results suggest that methylation disruption is an early and critical step in malignant transformation.", "title": "Large-scale hypomethylated blocks associated with Epstein-Barr virus-induced B-cell immortalization." }, { "docid": "24221369", "text": "The cytosolic helicase retinoic acid-inducible gene-I (RIG-I) initiates immune responses to most RNA viruses by detecting viral 5'-triphosphorylated RNA (pppRNA). Although endogenous mRNA is also 5'-triphosphorylated, backbone modifications and the 5'-ppp-linked methylguanosine ((m7)G) cap prevent immunorecognition. Here we show that the methylation status of endogenous capped mRNA at the 5'-terminal nucleotide (N1) was crucial to prevent RIG-I activation. Moreover, we identified a single conserved amino acid (H830) in the RIG-I RNA binding pocket as the mediator of steric exclusion of N1-2'O-methylated RNA. H830A alteration (RIG-I(H830A)) restored binding of N1-2'O-methylated pppRNA. Consequently, endogenous mRNA activated the RIG-I(H830A) mutant but not wild-type RIG-I. Similarly, knockdown of the endogenous N1-2'O-methyltransferase led to considerable RIG-I stimulation in the absence of exogenous stimuli. Studies involving yellow-fever-virus-encoded 2'O-methyltransferase and RIG-I(H830A) revealed that viruses exploit this mechanism to escape RIG-I. Our data reveal a new role for cap N1-2'O-methylation in RIG-I tolerance of self-RNA.", "title": "A Conserved Histidine in the RNA Sensor RIG-I Controls Immune Tolerance to N1-2'O-Methylated Self RNA." }, { "docid": "29107180", "text": "The structure of the human gene encoding the double-stranded RNA (dsRNA) adenosine deaminase (DRADA) was characterized. This nuclear localized enzyme is involved in the RNA editing required for the expression of certain subtypes of glutamate-gated ion channel subunits. The DRADA gene span 30 kb pairs and harbors 15 exons. The transcription of the DRADA gene driven by the putative promoter region, which contains no typical TATA or CCAAT box-like sequences, is initiated at multiple sites, 164 to 216 nucleotides upstream of the translation initiation codon. The three dsRNA binding motifs (DRBM), 70 amino acid residues long, are each encoded by two exons plus an intervening sequence that interrupts the motif at the identical amino acid position. This finding is consistent with the notion that the dsRNA binding domains may be composed of two separate functional subdomains. Fluorescent in situ hybridization localized the DRADA gene on the long arm chromosome 1, region q21. The gene structure and sequence information reported in this study will facilitate the investigation of involvement of DRADA in hereditary diseases that may be the result of malfunction of glutamate-gated ion channels.", "title": "Genomic organization and chromosomal location of the human dsRNA adenosine deaminase gene: the enzyme for glutamate-activated ion channel RNA editing." }, { "docid": "152245", "text": "The genomic RNA of an alphavirus encodes four different nonstructural proteins, nsP1, nsP2, nsP3, and nsP4. The polyprotein P123 is produced when translation terminates at an opal termination codon between nsP3 and nsP4. The polyprotein P1234 is produced when translational readthrough occurs or when the opal termination codon has been replaced by a sense codon in the alphavirus genome. Evolutionary pressures appear to have maintained genomic sequences encoding both a stop codon (opal) and an open reading frame (arginine) as a general feature of the O'nyong-nyong virus (ONNV) genome, indicating that both are required at some point. Alternate replication of ONNVs in both vertebrate and invertebrate hosts may determine predominance of a particular codon at this locus in the viral quasispecies. However, no systematic study has previously tested this hypothesis in whole animals. We report here the results of the first study to investigate in a natural mosquito host the functional significance of the opal stop codon in an alphavirus genome. We used a full-length cDNA clone of ONNV to construct a series of mutants in which the arginine between nsP3 and nsP4 was replaced with an opal, ochre, or amber stop codon. The presence of an opal stop codon upstream of nsP4 nearly doubled (75.5%) the infectivity of ONNV over that of virus possessing a codon for the amino acid arginine at the corresponding position (39.8%). Although the frequency with which the opal virus disseminated from the mosquito midgut did not differ significantly from that of the arginine virus on days 8 and 10, dissemination did began earlier in mosquitoes infected with the opal virus. Although a clear fitness advantage is provided to ONNV by the presence of an opal codon between nsP3 and nsP4 in Anopheles gambiae, sequence analysis of ONNV RNA extracted from mosquito bodies and heads indicated codon usage at this position corresponded with that of the virus administered in the blood meal. These results suggest that while selection of ONNV variants is occurring, de novo mutation at the position between nsP3 and nsP4 does not readily occur in the mosquito. Taken together, these results suggest that the primary fitness advantage provided to ONNV by the presence of an opal codon between nsP3 and nsP4 is related to mosquito infectivity.", "title": "Effects of an opal termination codon preceding the nsP4 gene sequence in the O'Nyong-Nyong virus genome on Anopheles gambiae infectivity." }, { "docid": "4323449", "text": "More than forty per cent of the mammalian genome is derived from retroelements, of which about one-quarter are endogenous retroviruses (ERVs). Some are still active, notably in mice the highly polymorphic early transposon (ETn)/MusD and intracisternal A-type particles (IAP). ERVs are transcriptionally silenced during early embryogenesis by histone and DNA methylation (and reviewed in ref. 7), although the initiators of this process, which is essential to protect genome integrity, remain largely unknown. KAP1 (KRAB-associated protein 1, also known as tripartite motif-containing protein 28, TRIM28) represses genes by recruiting the histone methyltransferase SETDB1, heterochromatin protein 1 (HP1) and the NuRD histone deacetylase complex, but few of its physiological targets are known. Two lines of evidence suggest that KAP1-mediated repression could contribute to the control of ERVs: first, KAP1 can trigger permanent gene silencing during early embryogenesis, and second, a KAP1 complex silences the retrovirus murine leukaemia virus in embryonic cells. Consistent with this hypothesis, here we show that KAP1 deletion leads to a marked upregulation of a range of ERVs, in particular IAP elements, in mouse embryonic stem (ES) cells and in early embryos. We further demonstrate that KAP1 acts synergistically with DNA methylation to silence IAP elements, and that it is enriched at the 5′ untranslated region (5′UTR) of IAP genomes, where KAP1 deletion leads to the loss of histone 3 lysine 9 trimethylation (H3K9me3), a hallmark of KAP1-mediated repression. Correspondingly, IAP 5′UTR sequences can impose in cis KAP1-dependent repression on a heterologous promoter in ES cells. Our results establish that KAP1 controls endogenous retroelements during early embryonic development.", "title": "KAP1 controls endogenous retroviruses in embryonic stem cells" }, { "docid": "13916484", "text": "COSMIC (http://www.sanger.ac.uk/cosmic) curates comprehensive information on somatic mutations in human cancer. Release v48 (July 2010) describes over 136,000 coding mutations in almost 542,000 tumour samples; of the 18,490 genes documented, 4803 (26%) have one or more mutations. Full scientific literature curations are available on 83 major cancer genes and 49 fusion gene pairs (19 new cancer genes and 30 new fusion pairs this year) and this number is continually increasing. Key amongst these is TP53, now available through a collaboration with the IARC p53 database. In addition to data from the Cancer Genome Project (CGP) at the Sanger Institute, UK, and The Cancer Genome Atlas project (TCGA), large systematic screens are also now curated. Major website upgrades now make these data much more mineable, with many new selection filters and graphics. A Biomart is now available allowing more automated data mining and integration with other biological databases. Annotation of genomic features has become a significant focus; COSMIC has begun curating full-genome resequencing experiments, developing new web pages, export formats and graphics styles. With all genomic information recently updated to GRCh37, COSMIC integrates many diverse types of mutation information and is making much closer links with Ensembl and other data resources.", "title": "COSMIC: mining complete cancer genomes in the Catalogue of Somatic Mutations in Cancer" }, { "docid": "13702924", "text": "Mosquitoes are vectors of a number of important human and animal diseases. The development of novel vector control strategies requires a thorough understanding of mosquito biology. To facilitate this, we used RNA-seq to identify novel genes and provide the first high-resolution view of the transcriptome throughout development and in response to blood feeding in a mosquito vector of human disease, Aedes aegypti, the primary vector for Dengue and yellow fever. We characterized mRNA expression at 34 distinct time points throughout Aedes development, including adult somatic and germline tissues, by using polyA+ RNA-seq. We identify a total of 14,238 novel new transcribed regions corresponding to 12,597 new loci, as well as many novel transcript isoforms of previously annotated genes. Altogether these results increase the annotated fraction of the transcribed genome into long polyA+ RNAs by more than twofold. We also identified a number of patterns of shared gene expression, as well as genes and/or exons expressed sex-specifically or sex-differentially. Expression profiles of small RNAs in ovaries, early embryos, testes, and adult male and female somatic tissues also were determined, resulting in the identification of 38 new Aedes-specific miRNAs, and ~291,000 small RNA new transcribed regions, many of which are likely to be endogenous small-interfering RNAs and Piwi-interacting RNAs. Genes of potential interest for transgene-based vector control strategies also are highlighted. Our data have been incorporated into a user-friendly genome browser located at www. Aedes.caltech.edu, with relevant links to Vectorbase (www.vectorbase.org).", "title": "The Developmental Transcriptome of the Mosquito Aedes aegypti, an Invasive Species and Major Arbovirus Vector" }, { "docid": "9704467", "text": "We developed the Yeast Gene Order Browser (YGOB; http://wolfe.gen.tcd.ie/ygob) to facilitate visual comparisons and computational analysis of synteny relationships in yeasts. The data presented in YGOB, currently covering seven species, are based on sets of homologous genes that have been intensively manually curated based on both sequence similarity and genomic context (synteny). We reconciled different laboratories' lists of paralogous Saccharomyces cerevisiae gene pairs formed by genome duplication (ohnologs), and present near-exhaustive lists of the ohnolog pairs retained in S. cerevisiae (551, including 22 previously unidentified), Saccharomyces castellii (599), and Candida glabrata (404).", "title": "in polyploid species" }, { "docid": "6820680", "text": "MicroRNAs (miRNAs) are short noncoding RNAs that exert posttranscriptional gene silencing and regulate gene expression. In addition to the hundreds of conserved cellular miRNAs that have been identified, miRNAs of viral origin have been isolated and found to modulate both the viral life cycle and the cellular transcriptome. Thus far, detection of virus-derived miRNAs has been largely limited to DNA viruses, suggesting that RNA viruses may be unable to exploit this aspect of transcriptional regulation. Lack of RNA virus-produced miRNAs has been attributed to the replicative constraints that would incur following RNase III processing of a genomic hairpin. To ascertain whether the generation of viral miRNAs is limited to DNA viruses, we investigated whether influenza virus could be designed to deliver functional miRNAs without affecting replication. Here, we describe a modified influenza A virus that expresses cellular microRNA-124 (miR-124). Insertion of the miR-124 hairpin into an intron of the nuclear export protein transcript resulted in endogenous processing and functional miR-124. We demonstrate that a viral RNA genome incorporating a hairpin does not result in segment instability or miRNA-mediated genomic targeting, thereby permitting the virus to produce a miRNA without having a negative impact on viral replication. This work demonstrates that RNA viruses can produce functional miRNAs and suggests that this level of transcriptional regulation may extend beyond DNA viruses.", "title": "Engineered RNA viral synthesis of microRNAs." }, { "docid": "13123189", "text": "BACKGROUND RNA-Seq is revolutionizing the way transcript abundances are measured. A key challenge in transcript quantification from RNA-Seq data is the handling of reads that map to multiple genes or isoforms. This issue is particularly important for quantification with de novo transcriptome assemblies in the absence of sequenced genomes, as it is difficult to determine which transcripts are isoforms of the same gene. A second significant issue is the design of RNA-Seq experiments, in terms of the number of reads, read length, and whether reads come from one or both ends of cDNA fragments. \n RESULTS We present RSEM, an user-friendly software package for quantifying gene and isoform abundances from single-end or paired-end RNA-Seq data. RSEM outputs abundance estimates, 95% credibility intervals, and visualization files and can also simulate RNA-Seq data. In contrast to other existing tools, the software does not require a reference genome. Thus, in combination with a de novo transcriptome assembler, RSEM enables accurate transcript quantification for species without sequenced genomes. On simulated and real data sets, RSEM has superior or comparable performance to quantification methods that rely on a reference genome. Taking advantage of RSEM's ability to effectively use ambiguously-mapping reads, we show that accurate gene-level abundance estimates are best obtained with large numbers of short single-end reads. On the other hand, estimates of the relative frequencies of isoforms within single genes may be improved through the use of paired-end reads, depending on the number of possible splice forms for each gene. \n CONCLUSIONS RSEM is an accurate and user-friendly software tool for quantifying transcript abundances from RNA-Seq data. As it does not rely on the existence of a reference genome, it is particularly useful for quantification with de novo transcriptome assemblies. In addition, RSEM has enabled valuable guidance for cost-efficient design of quantification experiments with RNA-Seq, which is currently relatively expensive.", "title": "RSEM: accurate transcript quantification from RNA-Seq data with or without a reference genome" }, { "docid": "27393799", "text": "To assess the relative importance of genetic and environmental effects on the body-mass index (weight in kilograms divided by the square of the height in meters), we studied samples of identical and fraternal twins, reared apart or reared together. The samples consisted of 93 pairs of identical twins reared apart, 154 pairs of identical twins reared together, 218 pairs of fraternal twins reared apart, and 208 pairs of fraternal twins reared together. The intrapair correlation coefficients of the values for body-mass index of identical twins reared apart were 0.70 for men and 0.66 for women. These are the most direct estimates of the relative importance of genetic influences (heritability) on the body-mass index, and they were only slightly lower than those for twins reared together in this and earlier studies. Similar estimates were derived from maximum-likelihood model-fitting analyses--0.74 for men and 0.69 for women. Nonadditive genetic variance made a significant contribution to the estimates of heritability, particularly among men. Of the potential environmental influences, only those unique to the individual and not those shared by family members were important, contributing about 30 percent of the variance. Sharing the same childhood environment did not contribute to the similarity of the body-mass index of twins later in life. We conclude that genetic influences on body-mass index are substantial, whereas the childhood environment has little or no influence. These findings corroborate and extend the results of earlier studies of twins and adoptees.", "title": "The body-mass index of twins who have been reared apart." }, { "docid": "22711954", "text": "OBJECTIVE Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. \n DESIGN Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30% of the trial); analysis of funnel plots from 37 meta-analyses identified from a hand search of four leading general medicine journals 1993-6 and 38 meta-analyses from the second 1996 issue of the Cochrane Database of Systematic Reviews. \n MAIN OUTCOME MEASURE Degree of funnel plot asymmetry as measured by the intercept from regression of standard normal deviates against precision. \n RESULTS In the eight pairs of meta-analysis and large trial that were identified (five from cardiovascular medicine, one from diabetic medicine, one from geriatric medicine, one from perinatal medicine) there were four concordant and four discordant pairs. In all cases discordance was due to meta-analyses showing larger effects. Funnel plot asymmetry was present in three out of four discordant pairs but in none of concordant pairs. In 14 (38%) journal meta-analyses and 5 (13%) Cochrane reviews, funnel plot asymmetry indicated that there was bias. \n CONCLUSIONS A simple analysis of funnel plots provides a useful test for the likely presence of bias in meta-analyses, but as the capacity to detect bias will be limited when meta-analyses are based on a limited number of small trials the results from such analyses should be treated with considerable caution.", "title": "Bias in meta-analysis detected by a simple, graphical test." } ]

[ { "docid": "25001628", "text": "To identify previously unknown platelet receptors we compared the transcriptomes of in vitro differentiated megakaryocytes (MKs) and erythroblasts (EBs). RNA was obtained from purified, biologically paired MK and EB cultures and compared using cDNA microarrays. Bioinformatical analysis of MK-up-regulated genes identified 151 transcripts encoding transmembrane domain-containing proteins. Although many of these were known platelet genes, a number of previously unidentified or poorly characterized transcripts were also detected. Many of these transcripts, including G6b, G6f, LRRC32, LAT2, and the G protein-coupled receptor SUCNR1, encode proteins with structural features or functions that suggest they may be involved in the modulation of platelet function. Immunoblotting on platelets confirmed the presence of the encoded proteins, and flow cytometric analysis confirmed the expression of G6b, G6f, and LRRC32 on the surface of platelets. Through comparative analysis of expression in platelets and other blood cells we demonstrated that G6b, G6f, and LRRC32 are restricted to the platelet lineage, whereas LAT2 and SUCNR1 were also detected in other blood cells. The identification of the succinate receptor SUCNR1 in platelets is of particular interest, because physiologically relevant concentrations of succinate were shown to potentiate the effect of low doses of a variety of platelet agonists.", "title": "Comparative gene expression profiling of in vitro differentiated megakaryocytes and erythroblasts identifies novel activatory and inhibitory platelet membrane proteins." } ]

[ { "docid": "2931832", "text": "Activated platelets promote tumor cell growth, angiogenesis, and invasion. Platelet activity can be inferred by platelet volume indices (PVIs), which include platelet distribution width (PDW), mean platelet volume (MPV), platelet distribution width-to-platelet count ratio (PDW/P), and mean platelet volume-to-platelet count ratio. Platelets and platelet-related markers, such as the platelet-to-lymphocyte ratio, have been found to be significant prognostic factors in patients with breast cancer. However, the role of PVIs for predicting survival in breast cancer remains unknown; hence, we performed this retrospective analysis of 275 patients with breast cancer. PVIs were compared with clinicopathological variables, and were assessed to identify independent indicators associated with disease-free survival (DFS) using the Cox proportional hazards model. An elevated PDW/P significantly correlated with age and HER2 status. Univariate analysis revealed that elevated PDW, MPV, and PDW/P as well as tumor size, nuclear grade, and lymph node involvement were significantly associated with inferior DFS rates (tumor size: p<0.01; nuclear grade, lymph node involvement, PDW, MPV, and PDW/P: p<0.05). On multivariate analysis, a large tumor size and elevated PDW/P were significant prognostic factors for DFS, with hazard ratios of 3.24 (95% confidence interval [CI]: 1.24-8.47) and 2.99 (95% CI: 1.18-7.57), respectively (p<0.05). Our study is the first to reveal that an elevated PDW/P significantly reduces DFS in patients with breast carcinoma. Measuring the PDW/P is simple, relatively inexpensive, and almost universally available using routine blood counts; this makes it an attractive biomarker for improved risk assessment.", "title": "The prognostic impact of the platelet distribution width-to-platelet count ratio in patients with breast cancer" }, { "docid": "21164071", "text": "Integrins are membrane receptors which mediate cell-cell or cell-matrix adhesion. Integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) acts as a fibrinogen receptor of platelets and mediates platelet aggregation. Platelet activation is required for alpha IIb beta 3 to shift from noncompetent to competent for binding soluble fibrinogen. The steps involved in this transition are poorly understood. We have studied a variant of Glanzmann thrombasthenia, a congenital bleeding disorder characterized by absence of platelet aggregation and fibrinogen binding. The patient's platelets did not bind fibrinogen after platelet activation by ADP or thrombin, though his platelets contained alpha IIb beta 3. However, isolated alpha IIb beta 3 was able to bind to an Arg-Gly-Asp-Ser affinity column, and binding of soluble fibrinogen to the patient's platelets could be triggered by modulators of alpha IIb beta 3 conformation such as the Arg-Gly-Asp-Ser peptide and alpha-chymotrypsin. These data suggested that a functional Arg-Gly-Asp binding site was present within alpha IIb beta 3 and that the patient's defect was not secondary to a blockade of alpha IIb beta 3 in a noncompetent conformational state. This was evocative of a defect in the coupling between platelet activation and alpha IIb beta 3 up-regulation. We therefore sequenced the cytoplasmic domain of beta 3, following polymerase chain reaction (PCR) on platelet RNA, and found a T-->C mutation at nucleotide 2259, corresponding to a Ser-752-->Pro substitution. This mutation is likely to be responsible for the uncoupling of alpha IIb beta 3 from cellular activation because (i) it is not a polymorphism, (ii) it is the only mutation in the entire alpha IIb beta 3 sequence, and (iii) genetic analysis of the family showed that absence of the Pro-752 beta 3 allele was associated with the normal phenotype. Our data thus identify the C-terminal portion of the cytoplasmic domain of beta 3 as an intrinsic element in the coupling between alpha IIb beta 3 and platelet activation.", "title": "Ser-752-->Pro mutation in the cytoplasmic domain of integrin beta 3 subunit and defective activation of platelet integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) in a variant of Glanzmann thrombasthenia." }, { "docid": "14075252", "text": "Paraneoplastic thrombocytosis is associated with many solid tumors and often correlates with reduced survival. Recent studies suggest that a pathogenic feed back loop may be operative between platelets and tumor cells, with reciprocal interactions between tumor growth/metastasis and thrombocytosis/platelet activation. Specific molecular pathways have been identified in which tumors can stimulate platelet production and activation; activated platelets can, in turn, promote tumor growth and metastasis. Taken together, these findings provide exciting new potential targets for therapeutic intervention.", "title": "Paraneoplastic thrombocytosis: the secrets of tumor self-promotion." }, { "docid": "24670522", "text": "The intracellular Ca(2+) concentration of many nonexcitable cells is regulated by calcium store release and store-operated calcium entry (SOCE). In platelets, STIM1 was recently identified as the main calcium sensor expressed in the endoplasmic reticulum. To evaluate the role of the SOC channel moiety, Orai1, in platelet SOCE, we generated mice expressing a mutated, inactive form of Orai1 in blood cells only (Orai1(R93W)). Platelets expressing Orai1(R93W) were characterized by markedly reduced SOCE and impaired agonist-induced increases in [Ca(2+)](i). Orai1(R93W) platelets showed reduced integrin activation and impaired degranulation when stimulated with low agonist concentrations under static conditions. This defect, however, did not significantly affect the ability of Orai1(R93W) platelets to aggregate or to adhere to collagen under arterial flow conditions ex vivo. In contrast, these adherent Orai1(R93W) platelets were defective in surface phosphatidylserine exposure, suggesting that Orai1 is crucial for the platelets' procoagulant response rather than for other Ca(2+)-dependent cellular responses.", "title": "R93W mutation in Orai1 causes impaired calcium influx in platelets." }, { "docid": "5266423", "text": "The study of thrombopoiesis has evolved greatly since an era when platelets were termed \"the dust of the blood,\" only about 100 years ago. During this time megakaryocytes were identified as the origin of blood platelets; marrow-derived megakaryocytic progenitor cells were functionally defined and then purified; and the primary regulator of the process, thrombopoietin, was cloned and characterized and therapeutic thrombopoietic agents developed. During this journey we continue to learn that the physiologic mechanisms that drive proplatelet formation can be recapitulated in cell-free systems and their biochemistry evaluated; the molecular underpinnings of endomitosis are being increasingly understood; the intracellular signals sent by engagement of a large number of megakaryocyte surface receptors have been defined; and many of the transcription factors that drive megakaryocytic fate determination have been identified and experimentally manipulated. While some of these biologic processes mimic those seen in other cell types, megakaryocytes and platelets possess enough unique developmental features that we are virtually assured that continued study of thrombopoiesis will yield innumerable clinical and scientific insights for many decades to come.", "title": "Historical review: megakaryopoiesis and thrombopoiesis." }, { "docid": "22123421", "text": "BACKGROUND Mean platelet volume (MPV) is a platelet volume index. Classically, MPV was recognized as a hallmark of platelet activation. Recent studies have revealed that the MPV and MPV/platelet count (PC) ratio can predict long-term mortality in patients with ischemic cardio-vascular disease. In addition, these indices were correlated with the pathophysiological characteristics of patients with various disorders, including malignant tumors. \n PATIENTS AND METHODS We retrospectively analyzed various hematological indices of patients with advanced non-small cell lung cancer (NSCLC). The aim of this study was to evaluate the contribution of platelet volume indices to survival in these patients. \n RESULTS A total of 268 patients were enrolled in the study. The median age of the patients was 68 years (range: 31-87 years). We compared various hematological indices between the NSCLC group and an age- and sex-matched comparator group. MPV was significantly decreased in the NSCLC group compared to the comparator group. In contrast, the PC was significantly increased in the NSCLC group. Consequently, the MPV/PC ratio was also decreased in the NSCLC group (0.397 vs. 0.501). In receiver operating characteristics (ROC) curve analysis, the MPV/PC ratio was associated with a sensitivity of 62.3% and a specificity of 74.6% at a cutoff value of 0.408730 (area under the curve [AUC], 0.72492)]. Univariate analysis revealed that overall survival (OS) was significantly shorter in the group with a low MPV/PC ratio than in the other group (median survival time [MST]: 10.3 months vs. 14.5 months, log-rank, P=0.0245). Multivariate analysis confirmed that a low MPV/PC ratio was an independent unfavorable predictive factor for OS (hazard ratio [HR]: 1.668, 95% confidence interval [CI]: 1.235-2.271, P=0.0008). \n CONCLUSION These data clearly demonstrate that the MPV/PC ratio was closely associated with survival in patients with advanced NSCLC.", "title": "Prognostic impact of the mean platelet volume/platelet count ratio in terms of survival in advanced non-small cell lung cancer." }, { "docid": "44387884", "text": "The abnormal metabolic state that accompanies diabetes renders arteries susceptible to atherosclerosis, being capable of altering the functional properties of multiple cell types, including endothelium and platelets. In particular, an altered platelet metabolism and changes in intraplatelet signaling pathways may contribute to the pathogenesis of atherothrombotic complications of diabetes. A variety of mechanisms may be responsible for enhanced platelet aggregation. Among them, hyperglycemia may represent a causal factor for in vivo platelet activation, and may be responsible for nonenzymatic glycation of platelet glycoproteins, causing changes in their structure and conformation, as well as alterations of membrane lipid dynamics. Furthermore, hyperglycemia-induced oxidative stress is responsible for enhanced peroxidation of arachidonic acid to form biologically active isoprostanes, which represents an important biochemical link between impaired glycemic control and persistent platelet activation. Finally, increased oxidative stress is responsible for activation of transcription factors and expression of redox-sensitive genes leading to a phenotypic switch of endothelium toward an adhesive, pro-thrombotic condition, initial platelet activation, adhesion and subsequent platelet aggregate formation. All this evidence is strengthened by the results of clinical trials documenting the beneficial effects of metabolic control on platelet function, and by the finding that aspirin treatment may even be more beneficial in diabetic than in high-risk non-diabetic patients. Attention to appropriate medical management of diabetic patients will have great impact on long-term outcome in this high-risk population.", "title": "Platelet activation in type 2 diabetes mellitus." }, { "docid": "5238341", "text": "Although once primarily recognized for its roles in hemostasis and thrombosis, the platelet has been increasingly recognized as a multipurpose cell. Indeed, circulating platelets have the ability to influence a wide range of seemingly unrelated pathophysiologic events. Here, we highlight some of the notable observations that link platelets to inflammation, reinforcing the platelet's origin from a lower vertebrate cell type with both hemostatic and immunologic roles. In addition, we consider the relevance of platelets in cancer biology by focusing on the hallmarks of cancer and the ways platelets can influence multistep development of tumors. Beyond its traditional role in hemostasis and thrombosis, the platelet's involvement in the interplay between hemostasis, thrombosis, inflammation, and cancer is likely complex, yet extremely important in each disease process. The existence of animal models of platelet dysfunction and currently used antiplatelet therapies provide a framework for understanding mechanistic insights into a wide range of pathophysiologic events. Thus, the basic scientist studying platelet function can think beyond the traditional hemostasis and thrombosis paradigms, while the practicing hematologist must appreciate platelet relevance in a wide range of disease processes.", "title": "Platelets at the interface of thrombosis, inflammation, and cancer." }, { "docid": "71625969", "text": "Abstract Background: For the past 20 years numerous epidemiological studies have correlated the consumption of alcohol and a variety of disease states: overall mortality, arteriosclerotic vascular diseases, hypertension, cancers, peptic ulcer, respiratory infections, gall stones, kidney stones, age-related macular degeneration, bone density, and cognitive function. Methods: A review of these articles reveals that each of these studies has compared the outcome of individuals at various levels of alcohol consumption with that of abstainers. Results: Each analysis has identified a U-shaped or J-shaped curve of reduced relative risk for a given disease state compared with abstainers. A clear definition of consumption in moderation becomes evident: for men it should not exceed 2 to 4 drinks per day, and for women it should not exceed 1 to 2 drinks per day. Conclusions: Alcohol by itself has favorable effects on the level of high-density lipoprotein cholesterol, and inhibition of platelet aggregation. Wine, particularly red wine, has high levels of phenolic compounds that favorably influence multiple biochemical systems, such as increased high-density lipoprotein cholesterol, antioxidant activity, decreased platelet aggregation and endothelial adhesion, suppression of cancer cell growth, and promotion of nitric oxide production.", "title": "Alcohol, wine, and health" }, { "docid": "19482914", "text": "Integrin-mediated platelet adhesion and aggregation are essential for sealing injured blood vessels and preventing blood loss, and excessive platelet aggregation can initiate arterial thrombosis, causing heart attacks and stroke. To ensure that platelets aggregate only at injury sites, integrins on circulating platelets exist in a low-affinity state and shift to a high-affinity state (in a process known as integrin activation or priming) after contacting a wounded vessel. The shift is mediated through binding of the cytoskeletal protein Talin to the β subunit cytoplasmic tail. Here we show that platelets lacking the adhesion plaque protein Kindlin-3 cannot activate integrins despite normal Talin expression. As a direct consequence, Kindlin-3 deficiency results in severe bleeding and resistance to arterial thrombosis. Mechanistically, Kindlin-3 can directly bind to regions of β-integrin tails distinct from those of Talin and trigger integrin activation. We have therefore identified Kindlin-3 as a novel and essential element for platelet integrin activation in hemostasis and thrombosis.", "title": "Kindlin-3 is essential for integrin activation and platelet aggregation" }, { "docid": "15981174", "text": "To generate transgenic mice that express Cre-recombinase exclusively in the megakaryocytic lineage, we modified a mouse bacterial artificial chromosome (BAC) clone by homologous recombination and replaced the first exon of the platelet factor 4 (Pf4), also called CXCL4, with a codon-improved Cre cDNA. Several strains expressing the transgene were obtained and one strain, Q3, was studied in detail. Crossing Q3 mice with the ROSA26-lacZ reporter strain showed that Cre-recombinase activity was confined to megakaryocytes. These results were further verified by crossing the Q3 mice with a strain containing loxP-flanked integrin beta1. Excision of this conditional allele in megakaryocytes was complete at the DNA level, and platelets were virtually devoid of the integrin beta1 protein. The Pf4-Cre transgenic strain will be a valuable tool to study megakaryopoiesis, platelet formation, and platelet function.", "title": "Pf4-Cre transgenic mice allow the generation of lineage-restricted gene knockouts for studying megakaryocyte and platelet function in vivo." }, { "docid": "22371455", "text": "Although drugs are a common cause of acute immune-mediated thrombocytopenia in adults, the drug etiology is often initially unrecognized. Most cases of drug-induced thrombocytopenia (DITP) are caused by drug-dependent antibodies that are specific for the drug structure and bind tightly to platelets by their Fab regions but only in the presence of the drug. A comprehensive database of 1301 published reports describing 317 drugs, available at www.ouhsc.edu/platelets, provides information on the level of evidence for a causal relation to thrombocytopenia. Typically, DITP occurs 1 to 2 weeks after beginning a new drug or suddenly after a single dose when a drug has previously been taken intermittently. However, severe thrombocytopenia can occur immediately after the first administration of antithrombotic agents that block fibrinogen binding to platelet GP IIb-IIIa, such as abciximab, tirofiban, and eptifibatide. Recovery from DITP usually begins within 1 to 2 days of stopping the drug and is typically complete within a week. Drug-dependent antibodies can persist for many years; therefore, it is important that the drug etiology be confirmed and the drug be avoided thereafter.", "title": "Drug-induced thrombocytopenia: pathogenesis, evaluation, and management." }, { "docid": "23195674", "text": "OBJECTIVES To evaluate the relationship between CD40/CD40L system and increased thrombogenesis in AF, and to test the effects of simvastatin treatment. \n METHODS In vitro study using human tissue, University Hospital (tertiary referral center). Experiments on right atrial segments obtained before the onset of cardiopulmonary bypass were done in either presence or absence of 5 microM simvastatin. Two groups of patients in either chronic atrial fibrillation or sinus rhythm at the time of cardiac surgery. The endocardial expression of CD40, the release of CD40L, and adhesion of platelets to endocardium. Additionally, the thickness of platelet aggregates and the platelet distribution on the endocardium were also evaluated. \n RESULTS Atrial fibrillation was associated with a significant increase of endocardial CD40 expression (293.1+/-55.1 pg/ml vs. 230.9+/-53.3 pg/ml, p<0.01), and platelet-endocardial adhesion compared with sinus rhythm atria (10.8+/-2.2 vs. 5.2+/-1.3 platelet CD41 AU p<0.01). At immunofluorescence about 62% of fibrillating endocardium was covered by platelets, compared with 12% of not sinus rhythm atria. Addition of simvastatin significantly reduced CD40 expression as well as platelet adhesion to fibrillating atria; its efficacy was not reversed by the addition of mevalonic acid. \n CONCLUSIONS Chronic atrial fibrillation acutely upregulates CD40 expression as well as platelet adhesion to the endocardium. Simvastatin is effective in modulating this expression, thus it may potentially contribute to reduce the risk of intra-atrial thrombus formation.", "title": "Simvastatin reduces platelet-endocardium adhesion in atrial fibrillation." }, { "docid": "33118292", "text": "WHAT IS KNOWN AND OBJECTIVE There is a growing body of experimental and clinical evidence for the atherogenic and pro-thrombotic potential of Lipoprotein(a) [Lp(a)], as well as for its causative role in coronary heart disease and stroke. We comment on novel strategies for reducing Lp(a) levels. COMMENT Irrespective of the underlying biological mechanisms explaining the athero-thrombotic potential of this lipoprotein, most work has focused on the identification of suitable therapies for hyperlipoproteinemia(a). These include apheresis techniques, nicotinic acid and statins. None of these strategies have been shown to be definitely effective or convenient for the patient and new strategies are being attempted. Promising results are emerging with therapeutic interventions targeting the 'inflammatory pathways' by inhibition of Interleukin-6 (IL-6) signalling with natural compounds (e.g., Ginko biloba) or the IL-6 receptor antibody Tocilizumab. These may both lower Lp(a) and cardiovascular risk of the patients. Besides inhibiting platelet function, antiplatelet therapy with aspirin may also decrease the plasma concentration of Lp(a) and modulate its influence on platelets. WHAT IS NEW AND CONCLUSION We highlight the inadequacy of current approaches for lowering Lp(a) and draw attention to novel insights that may lead to better treatment.", "title": "Optimal therapy for reduction of lipoprotein(a)." }, { "docid": "25420421", "text": "Little is known about the changes in white blood cells and platelets in children with falciparum malaria in endemic areas. We measured the white cell count (WCC) and platelets of 230 healthy children from the community, 1369 children admitted to hospital with symptomatic malaria, and 1461 children with other medical conditions. Children with malaria had a higher WCC compared with community controls, and leucocytosis was strongly associated with younger age, deep breathing, severe anaemia, thrombocytopenia and death. The WCC was not associated with a positive blood culture. In children with malaria, high lymphocyte and low monocyte counts were independently associated with mortality. A platelet count of less than 150 x 109/l was found in 56.7% of children with malaria, and was associated with age, prostration and parasite density, but not with bleeding problems or mortality. The mean platelet volume was also higher in children with malaria compared with other medical conditions. This may reflect early release from the bone marrow in response to peripheral platelet destruction. Thus, leucocytosis was associated with both severity and mortality in children with falciparum malaria, irrespective of bacteraemia, whereas thrombocytopenia, although very common, was not associated with adverse outcome.", "title": "Changes in white blood cells and platelets in children with falciparum malaria: relationship to disease outcome." }, { "docid": "7873737", "text": "BACKGROUND Diabetes mellitus is a major risk factor for adverse outcomes after acute coronary syndromes (ACS). Because this disease may be associated with increased platelet aggregation, we investigated whether diabetic patients with ACS derive particular benefit from platelet glycoprotein (GP) IIb/IIIa receptor inhibition. \n METHODS AND RESULTS We performed a meta-analysis of the diabetic populations enrolled in the 6 large-scale platelet GP IIb/IIIa inhibitor ACS trials: PRISM, PRISM-PLUS, PARAGON A, PARAGON B, PURSUIT, and GUSTO IV. Among 6458 diabetic patients, platelet GP IIb/IIIa inhibition was associated with a significant mortality reduction at 30 days, from 6.2% to 4.6% (OR 0.74; 95% CI 0.59 to 0.92; P=0.007). Conversely, 23 072 nondiabetic patients had no survival benefit (3.0% versus 3.0%). The interaction between platelet GP IIb/IIIa inhibition and diabetic status was statistically significant (P=0.036). Among 1279 diabetic patients undergoing percutaneous coronary intervention (PCI) during index hospitalization, the use of these agents was associated with a mortality reduction at 30 days from 4.0% to 1.2% (OR 0.30; 95% CI 0.14 to 0.69; P=0.002). \n CONCLUSIONS This meta-analysis, including the entire large-scale trial experience of intravenous platelet GP IIb/IIIa inhibitors for the medical management of non-ST-segment-elevation ACS, shows that these agents may significantly reduce mortality at 30 days in diabetic patients. Although not based on a randomized assessment, the survival benefit appears to be of greater magnitude in patients undergoing PCI. Therefore, the use of platelet GP IIb/IIIa inhibitors should be strongly considered in diabetic patients with ACS.", "title": "Platelet glycoprotein IIb/IIIa inhibitors reduce mortality in diabetic patients with non-ST-segment-elevation acute coronary syndromes." }, { "docid": "25543207", "text": "Platelet inhibitors are the mainstay treatment for patients with vascular diseases. The current 'gold standard' antiplatelet agent clopidogrel has several pharmacological and clinical limitations that have prompted the search for more effective platelet antagonists. The candidates include various blockers of the purinergic P2Y12 receptor such as prasugrel, an oral irreversible thienopyridine; two adenosine triphosphate analogues that bind reversibly to the P2Y12 receptor: ticagrelor (oral) and cangrelor (intravenous); elinogrel, a direct-acting reversible P2Y12 receptor inhibitor (the only antiplatelet compound that can be administered both intravenously and orally); BX 667, an orally active and reversible small-molecule P2Y12 receptor antagonist; SCH 530348, SCH 205831, SCH 602539 and E5555, highly selective and orally active antagonists on the protease-activated receptor 1. A number of drugs also hit new targets: terutroban, an oral, selective and specific inhibitor of the thromboxane receptor; ARC1779, a second-generation, nuclease resistant aptamer which inhibits von Willebrand factor-dependent platelet aggregation; ALX-0081, a bivalent humanized nanobody targeting the GPIb binding site of von Willebrand factor and AJW200, an IgG4 monoclonal antibody of von Willebrand factor. The pharmacology and clinical profiles of new platelet antagonists indicate that they provide more consistent, more rapid and more potent platelet inhibition than agents currently used. Whether these potential advantages will translate into clinical advantages will require additional comparisons in properly powered, randomized, controlled trials.", "title": "Pharmacokinetic, pharmacodynamic and clinical profile of novel antiplatelet drugs targeting vascular diseases." }, { "docid": "2842550", "text": "BACKGROUND Platelet deposition and aggregation are central to the pathogenesis of ischemic complications of acute coronary syndromes (ACS). Pharmacodynamic effects of the platelet glycoprotein IIb/IIIa antagonist eptifibatide have been delineated in healthy subjects but not in patients with ACS. We assessed effects of eptifibatide on ex vivo platelet aggregation in patients enrolled in the Platelet glycoprotein IIb/IIIa in Unstable angina: Receptor Suppression Using Integrilin (eptifibatide) Therapy (PURSUIT) trial of ACS. \n METHODS AND RESULTS Patients were randomly assigned to an intravenous bolus (180 microgram/kg) and 72-hour infusion of eptifibatide (2.0 microgram/kg per minute, n=48) or placebo (n=50). We assessed correlations of plasma eptifibatide levels with receptor occupancy and inhibition of ex vivo platelet aggregation at 5 minutes and 1, 4, 24, 48, and 72 hours during treatment and 4 and 8 hours after termination of infusion. Blood was collected in buffered citrate and D-phenylalanyl-L-prolyl-L-arginine chloromethylketone anticoagulants. Although eptifibatide produced profound, prolonged inhibition of platelet aggregation during therapy, aggregation appeared to recover partially by 4 hours after the bolus. The aggregation response was greater with thrombin receptor agonist peptide versus ADP stimulation; inhibition of platelet aggregation was greater in blood samples anticoagulated with citrate versus D-phenylalanyl-L-prolyl-L-arginine chloromethylketone (PPACK). Plasma eptifibatide levels correlated significantly with receptor occupancy but not with inhibition of platelet aggregation. \n CONCLUSIONS A bolus and infusion of eptifibatide inhibits platelet aggregation profoundly in patients with ACS and is followed by brief, partial recovery. These results enhance our understanding of the relation between pharmacodynamic and clinical effects of eptifibatide in such patients and may have important implications for its use in percutaneous interventions.", "title": "Pharmacodynamics and pharmacokinetics of eptifibatide in patients with acute coronary syndromes: prospective analysis from PURSUIT." }, { "docid": "22401720", "text": "Angiogenesis is a significant prognostic factor in breast cancer, but the factors that control angiogenesis in vivo are not well defined. Multiple angiogenic polypeptides are known, and we have determined the expression of seven of these in primary human breast cancers; the relationship of expression to estrogen receptor and vascular density was also examined. Vascular endothelial growth factor (VEGF) and its four isoforms (121, 165, 189, and 206 amino acids), transforming growth factor (TGF)-beta1, pleiotrophin, acidic and basic fibroblast growth factor (FGF), placental growth factor, and thymidine phosphorylase (platelet-derived endothelial cell growth factor) were quantitated by RNase protection analysis. beta-FGF was also measured by ELISA. The estrogen receptor (ER), epidermal growth factor receptor, and vascular density were analyzed in 64 primary breast cancers. All tumors expressed at least six different vascular growth factors. VEGF was most abundant, and the transcript for the 121-amino acid form predominated. Other angiogenic factors expressed at high levels were thymidine phosphorylase and TGF-beta1. Expression of most of the angiogenic factors did not correlate with that of ER or vascular density. However, thymidine phosphorylase did, with a correlation coefficient of 0.3 (P = 0.03). There were significant associations of pleiotrophin with acidic FGF expression (P = 0.001) and TGF-beta with platelet-derived endothelial cell growth factor expression (P = 0.001). Thus, angiogenesis may involve a coordinate regulation of some vascular growth factors. High VEGF expression correlated with poor prognosis in univariate analysis (P = 0.03), as did ER and epidermal growth factor receptor expression. Basic FGF was also assessed by ELISA and was more highly expressed in tumors than normal breast tissues (median, 346 microg/ml cytosol; range, 54-1323 versus median, 149; range, 32-509; P = 0.01). Implications for therapy are that broad spectrum agents that block features common to these factors may be useful (e.g., antagonism of heparin-binding activity agents), because so many angiogenic factors are expressed. Inhibiting endothelial migration or agents directly toxic to endothelium would be of value in a combined approach to therapy.", "title": "Expression of the angiogenic factors vascular endothelial cell growth factor, acidic and basic fibroblast growth factor, tumor growth factor beta-1, platelet-derived endothelial cell growth factor, placenta growth factor, and pleiotrophin in human primary breast cancer and its relation to angiogenes" } ]

[ { "docid": "4632921", "text": "In this study, we used whole-genome sequencing and gene expression profiling of 215 human induced pluripotent stem cell (iPSC) lines from different donors to identify genetic variants associated with RNA expression for 5,746 genes. We were able to predict causal variants for these expression quantitative trait loci (eQTLs) that disrupt transcription factor binding and validated a subset of them experimentally. We also identified copy-number variant (CNV) eQTLs, including some that appear to affect gene expression by altering the copy number of intergenic regulatory regions. In addition, we were able to identify effects on gene expression of rare genic CNVs and regulatory single-nucleotide variants and found that reactivation of gene expression on the X chromosome depends on gene chromosomal position. Our work highlights the value of iPSCs for genetic association analyses and provides a unique resource for investigating the genetic regulation of gene expression in pluripotent cells.", "title": "Large-Scale Profiling Reveals the Influence of Genetic Variation on Gene Expression in Human Induced Pluripotent Stem Cells." } ]

[ { "docid": "6401675", "text": "Detection of new genomic control elements is critical in understanding transcriptional regulatory networks in their entirety. We studied the genome-wide binding locations of three key regulatory proteins (POU5F1, also known as OCT4; NANOG; and CTCF) in human and mouse embryonic stem cells. In contrast to CTCF, we found that the binding profiles of OCT4 and NANOG are markedly different, with only ∼5% of the regions being homologously occupied. We show that transposable elements contributed up to 25% of the bound sites in humans and mice and have wired new genes into the core regulatory network of embryonic stem cells. These data indicate that species-specific transposable elements have substantially altered the transcriptional circuitry of pluripotent stem cells.", "title": "Transposable elements have rewired the core regulatory network of human embryonic stem cells" }, { "docid": "25799020", "text": "Transcriptional regulatory elements play essential roles in gene expression during animal development and cellular response to environmental signals, but our knowledge of these regions in the human genome is limited despite the availability of the complete genome sequence. Promoters mark the start of every transcript and are an important class of regulatory elements. A large, complex protein structure known as the pre-initiation complex (PIC) is assembled on all active promoters, and the presence of these proteins distinguishes promoters from other sequences in the genome. Using components of the PIC as tags, we isolated promoters directly from human cells as protein-DNA complexes and identified the resulting DNA sequences using genomic tiling microarrays. Our experiments in four human cell lines uncovered 252 PIC-binding sites in 44 semirandomly selected human genomic regions comprising 1% (30 megabase pairs) of the human genome. Nearly 72% of the identified fragments overlap or immediately flank 5' ends of known cDNA sequences, while the remainder is found in other genomic regions that likely harbor putative promoters of unannotated transcripts. Indeed, molecular analysis of the RNA isolated from one cell line uncovered transcripts initiated from over half of the putative promoter fragments, and transient transfection assays revealed promoter activity for a significant proportion of fragments when they were fused to a luciferase reporter gene. These results demonstrate the specificity of a genome-wide analysis method for mapping transcriptional regulatory elements and also indicate that a small, yet significant number of human genes remains to be discovered.", "title": "Direct isolation and identification of promoters in the human genome." }, { "docid": "3514072", "text": "Gene expression is controlled by the complex interaction of transcription factors binding to promoters and other regulatory DNA elements. One common characteristic of the genomic regions associated with regulatory proteins is a pronounced sensitivity to DNase I digestion. We generated genome-wide high-resolution maps of DNase I hypersensitive (DH) sites from both seedling and callus tissues of rice (Oryza sativa). Approximately 25% of the DH sites from both tissues were found in putative promoters, indicating that the vast majority of the gene regulatory elements in rice are not located in promoter regions. We found 58% more DH sites in the callus than in the seedling. For DH sites detected in both the seedling and callus, 31% displayed significantly different levels of DNase I sensitivity within the two tissues. Genes that are differentially expressed in the seedling and callus were frequently associated with DH sites in both tissues. The DNA sequences contained within the DH sites were hypomethylated, consistent with what is known about active gene regulatory elements. Interestingly, tissue-specific DH sites located in the promoters showed a higher level of DNA methylation than the average DNA methylation level of all the DH sites located in the promoters. A distinct elevation of H3K27me3 was associated with intergenic DH sites. These results suggest that epigenetic modifications play a role in the dynamic changes of the numbers and DNase I sensitivity of DH sites during development.", "title": "High-resolution mapping of open chromatin in the rice genome." }, { "docid": "12100854", "text": "Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) involves a marked reorganization of chromatin. To identify post-translational histone modifications that change in global abundance during this process, we have applied a quantitative mass-spectrometry-based approach. We found that iPSCs, compared with both the starting fibroblasts and a late reprogramming intermediate (pre-iPSCs), are enriched for histone modifications associated with active chromatin, and depleted for marks of transcriptional elongation and a subset of repressive modifications including H3K9me2/me3. Dissecting the contribution of H3K9 methylation to reprogramming, we show that the H3K9 methyltransferases Ehmt1, Ehmt2 and Setdb1 regulate global H3K9me2/me3 levels and that their depletion increases iPSC formation from both fibroblasts and pre-iPSCs. Similarly, we find that inhibition of heterochromatin protein-1γ (Cbx3), a protein known to recognize H3K9 methylation, enhances reprogramming. Genome-wide location analysis revealed that Cbx3 predominantly binds active genes in both pre-iPSCs and pluripotent cells but with a strikingly different distribution: in pre-iPSCs, but not in embryonic stem cells, Cbx3 associates with active transcriptional start sites, suggesting a developmentally regulated role for Cbx3 in transcriptional activation. Despite largely non-overlapping functions and the predominant association of Cbx3 with active transcription, the H3K9 methyltransferases and Cbx3 both inhibit reprogramming by repressing the pluripotency factor Nanog. Together, our findings demonstrate that Cbx3 and H3K9 methylation restrict late reprogramming events, and suggest that a marked change in global chromatin character constitutes an epigenetic roadblock for reprogramming.", "title": "Proteomic and genomic approaches reveal critical functions of H3K9 methylation and Heterochromatin Protein-1γ in reprogramming to pluripotency" }, { "docid": "2151983", "text": "Transcription factors (TFs) bind specifically to discrete regions of mammalian genomes called cis-regulatory elements. Among those are enhancers, which play key roles in regulation of gene expression during development and differentiation. Despite the recognized central regulatory role exerted by chromatin in control of TF functions, much remains to be learned regarding the chromatin structure of enhancers and how it is established. Here, we have analyzed on a genomic-scale enhancers that recruit FOXA1, a pioneer transcription factor that triggers transcriptional competency of these cis-regulatory sites. Importantly, we found that FOXA1 binds to genomic regions showing local DNA hypomethylation and that its cell-type-specific recruitment to chromatin is linked to differential DNA methylation levels of its binding sites. Using neural differentiation as a model, we showed that induction of FOXA1 expression and its subsequent recruitment to enhancers is associated with DNA demethylation. Concomitantly, histone H3 lysine 4 methylation is induced at these enhancers. These epigenetic changes may both stabilize FOXA1 binding and allow for subsequent recruitment of transcriptional regulatory effectors. Interestingly, when cloned into reporter constructs, FOXA1-dependent enhancers were able to recapitulate their cell type specificity. However, their activities were inhibited by DNA methylation. Hence, these enhancers are intrinsic cell-type-specific regulatory regions of which activities have to be potentiated by FOXA1 through induction of an epigenetic switch that includes notably DNA demethylation.", "title": "Epigenetic switch involved in activation of pioneer factor FOXA1-dependent enhancers." }, { "docid": "3052213", "text": "The growing epidemic of obesity and metabolic diseases calls for a better understanding of adipocyte biology. The regulation of transcription in adipocytes is particularly important, as it is a target for several therapeutic approaches. Transcriptional outcomes are influenced by both histone modifications and transcription factor binding. Although the epigenetic states and binding sites of several important transcription factors have been profiled in the mouse 3T3-L1 cell line, such data are lacking in human adipocytes. In this study, we identified H3K56 acetylation sites in human adipocytes derived from mesenchymal stem cells. H3K56 is acetylated by CBP and p300, and deacetylated by SIRT1, all are proteins with important roles in diabetes and insulin signaling. We found that while almost half of the genome shows signs of H3K56 acetylation, the highest level of H3K56 acetylation is associated with transcription factors and proteins in the adipokine signaling and Type II Diabetes pathways. In order to discover the transcription factors that recruit acetyltransferases and deacetylases to sites of H3K56 acetylation, we analyzed DNA sequences near H3K56 acetylated regions and found that the E2F recognition sequence was enriched. Using chromatin immunoprecipitation followed by high-throughput sequencing, we confirmed that genes bound by E2F4, as well as those by HSF-1 and C/EBPα, have higher than expected levels of H3K56 acetylation, and that the transcription factor binding sites and acetylation sites are often adjacent but rarely overlap. We also discovered a significant difference between bound targets of C/EBPα in 3T3-L1 and human adipocytes, highlighting the need to construct species-specific epigenetic and transcription factor binding site maps. This is the first genome-wide profile of H3K56 acetylation, E2F4, C/EBPα and HSF-1 binding in human adipocytes, and will serve as an important resource for better understanding adipocyte transcriptional regulation.", "title": "Genome-Wide Profiling of H3K56 Acetylation and Transcription Factor Binding Sites in Human Adipocytes" }, { "docid": "19851614", "text": "Polyphosphate (poly P) metabolism regulates the stress response in mycobacteria. Here we describe the regulatory architecture of a signal transduction system involving the two-component system (TCS) SenX3-RegX3, the extracytoplasmic function sigma factor sigma E (SigE) and the poly P-synthesizing enzyme polyphosphate kinase 1 (PPK1). The ppk1 promoter of Mycobacterium tuberculosis is activated under phosphate starvation. This is attenuated upon deletion of an imperfect palindrome likely representing a binding site for the response regulator RegX3, a component of the two-component system SenX3-RegX3 that responds to phosphate starvation. Binding of phosphorylated RegX3 to this site was confirmed by electrophoretic mobility shift assay. The activity of the ppk1 promoter was abrogated upon deletion of a putative SigE binding site. Pull-down of SigE from M. tuberculosis lysates of phosphate-starved cells with a biotinylated DNA harbouring the SigE binding site confirmed the likely binding of SigE to the ppk1 promoter. In vitro transcription corroborated the involvement of SigE in ppk1 transcription. Finally, the overexpression of RseA (anti-SigE) attenuated ppk1 expression under phosphate starvation, supporting the role of SigE in ppk1 transcription. The regulatory elements identified in ppk1 transcription in this study, combined with our earlier observation that PPK1 is itself capable of regulating sigE expression via the MprAB TCS, suggest the presence of multiple positive-feedback loops in this signalling circuit. In combination with the sequestering effect of RseA, we hypothesize that this architecture could be linked to bistability in the system that, in turn, could be a key element of persistence in M. tuberculosis.", "title": "Polyphosphate kinase 1, a central node in the stress response network of Mycobacterium tuberculosis, connects the two-component systems MprAB and SenX3-RegX3 and the extracytoplasmic function sigma factor, sigma E." }, { "docid": "5116145", "text": "The sequence specificity of DNA-binding proteins is the primary mechanism by which the cell recognizes genomic features. Here, we describe systematic determination of yeast transcription factor DNA-binding specificities. We obtained binding specificities for 112 DNA-binding proteins representing 19 distinct structural classes. One-third of the binding specificities have not been previously reported. Several binding sequences have striking genomic distributions relative to transcription start sites, supporting their biological relevance and suggesting a role in promoter architecture. Among these are Rsc3 binding sequences, containing the core CGCG, which are found preferentially approximately 100 bp upstream of transcription start sites. Mutation of RSC3 results in a dramatic increase in nucleosome occupancy in hundreds of proximal promoters containing a Rsc3 binding element, but has little impact on promoters lacking Rsc3 binding sequences, indicating that Rsc3 plays a broad role in targeting nucleosome exclusion at yeast promoters.", "title": "A library of yeast transcription factor motifs reveals a widespread function for Rsc3 in targeting nucleosome exclusion at promoters." }, { "docid": "6826100", "text": "Induced pluripotent stem cells (iPSCs) are commonly generated by transduction of Oct4, Sox2, Klf4, and Myc (OSKM) into cells. Although iPSCs are pluripotent, they frequently exhibit high variation in terms of quality, as measured in mice by chimera contribution and tetraploid complementation. Reliably high-quality iPSCs will be needed for future therapeutic applications. Here, we show that one major determinant of iPSC quality is the combination of reprogramming factors used. Based on tetraploid complementation, we found that ectopic expression of Sall4, Nanog, Esrrb, and Lin28 (SNEL) in mouse embryonic fibroblasts (MEFs) generated high-quality iPSCs more efficiently than other combinations of factors including OSKM. Although differentially methylated regions, transcript number of master regulators, establishment of specific superenhancers, and global aneuploidy were comparable between high- and low-quality lines, aberrant gene expression, trisomy of chromosome 8, and abnormal H2A.X deposition were distinguishing features that could potentially also be applicable to human.", "title": "The developmental potential of iPSCs is greatly influenced by reprogramming factor selection." }, { "docid": "11674288", "text": "Induced pluripotent stem cells (iPSCs) have been derived from various somatic cell populations through ectopic expression of defined factors. It remains unclear whether iPSCs generated from different cell types are molecularly and functionally similar. Here we show that iPSCs obtained from mouse fibroblasts, hematopoietic and myogenic cells exhibit distinct transcriptional and epigenetic patterns. Moreover, we demonstrate that cellular origin influences the in vitro differentiation potentials of iPSCs into embryoid bodies and different hematopoietic cell types. Notably, continuous passaging of iPSCs largely attenuates these differences. Our results suggest that early-passage iPSCs retain a transient epigenetic memory of their somatic cells of origin, which manifests as differential gene expression and altered differentiation capacity. These observations may influence ongoing attempts to use iPSCs for disease modeling and could also be exploited in potential therapeutic applications to enhance differentiation into desired cell lineages.", "title": "Cell type of origin influences the molecular and functional properties of mouse induced pluripotent stem cells" }, { "docid": "25994317", "text": "CACCC boxes are among the critical sequences present in regulatory elements of genes expressed in erythroid cells, as well as in selected other cell types. While an erythroid cell-specific CACCC-box-binding protein, EKLF, has been shown to be required in vivo for proper expression of the adult beta-globin gene, it is dispensable for the regulation of several other globin and nonglobin erythroid cell-expressed genes. In the work described here, we searched for additional CACCC-box transcription factors that might be active in murine erythroid cells. We identified a major gel shift activity (termed BKLF), present in yolk sac and fetal liver erythroid cells, that could be distinguished from EKLF by specific antisera. Through relaxed-stringency hybridization, we obtained the cDNA encoding BKLF, a highly basic, novel zinc finger protein that is related to EKLF and other Krüppel-like members in its DNA-binding domain but unrelated elsewhere. BKLF, which is widely but not ubiquitously expressed in cell lines, is highly expressed in the midbrain region of embryonic mice and appears to correspond to the gel shift activity TEF-2, a transcriptional activator implicated in regulation of the simian virus 40 enhancer and other CACCC-box-containing regulatory elements. Because BKLF binds with high affinity and preferentially over Sp1 to many CACCC sequences of erythroid cell expressed genes, it is likely to participate in the control of many genes whose expression appears independent of the action of EKLF.", "title": "Isolation and characterization of the cDNA encoding BKLF/TEF-2, a major CACCC-box-binding protein in erythroid cells and selected other cells." }, { "docid": "20179918", "text": "Both signal transducer and activator of transcription 3 (STAT3) and SALL4 are important in maintaining the pluripotent and self-renewal state of embryonic stem cells. We hypothesized that STAT3, a latent transcriptional factor, may regulate the gene expression of SALL4. In support of this hypothesis, DNA sequence analysis of the SALL4 gene promoter revealed four putative STAT3-binding sites. Using a SALL4-luciferase reporter gene assay, we found that modulation of the STAT3 activity significantly up-regulated the luciferase activity. By chromatin immunoprecipitation, the segment of the SALL4 promoter showing the highest affinity to STAT3 was localized to -366 to -163, in which there was only one putative STAT3 binding site starting at -199. Site-directed mutagenesis of all four putative STAT3-binding sites in the SALL4 promoter significantly reduced its responsiveness to STAT3, although the most dramatic effect was seen at the binding site starting at -199. We further tested the functional relationship between STAT3 and SALL4 using MDA-MB-231, a breast cell line carrying constitutive SALL4 expression and STAT3 activity. Down-regulation of the STAT3 activity using a dominant-negative construct resulted in a significant decrease in the expression of SALL4. To conclude, our data suggest that STAT3 and SALL4 probably cooperate in both physiological and pathological states.", "title": "Signal transducer and activator of transcription 3 is a transcriptional factor regulating the gene expression of SALL4." }, { "docid": "42787108", "text": "Lineage-specific differentiation potential varies among different human pluripotent stem cell (hPSC) lines, becoming therefore highly desirable to prospectively know which hPSC lines exhibit the highest differentiation potential for a certain lineage. We have compared the hematopoietic potential of 14 human embryonic stem cell (hESC)/induced pluripotent stem cell (iPSC) lines. The emergence of hemogenic progenitors, primitive and mature blood cells, and colony-forming unit (CFU) potential was analyzed at different time points. Significant differences in the propensity to differentiate toward blood were observed among hPSCs: some hPSCs exhibited good blood differentiation potential, whereas others barely displayed blood-differentiation capacity. Correlation studies revealed that the CFU potential robustly correlates with hemogenic progenitors and primitive but not mature blood cells. Developmental progression of mesoendodermal and hematopoietic transcription factors expression revealed no correlation with either hematopoietic initiation or maturation efficiency. Microarray studies showed distinct gene expression profile between hPSCs with good versus poor hematopoietic potential. Although neuroectoderm-associated genes were downregulated in hPSCs prone to hematopoietic differentiation many members of the Nodal/Activin signaling were upregulated, suggesting that this signaling predicts those hPSC lines with good blood-differentiation potential. The association between Nodal/Activin signaling and the hematopoietic differentiation potential was confirmed using loss- and gain-of-function functional assays. Our data reinforce the value of prospective comparative studies aimed at determining the lineage-specific differentiation potential among different hPSCs and indicate that Nodal/Activin signaling seems to predict those hPSC lines prone to hematopoietic specification.", "title": "Nodal/Activin signaling predicts human pluripotent stem cell lines prone to differentiate toward the hematopoietic lineage." }, { "docid": "29125354", "text": "The mechanisms underlying the silencing of alternative fate potentials in very early B cell precursors remain unclear. Using gain- and loss-of-function approaches together with a synthetic Zinc-finger polypeptide (6ZFP) engineered to prevent transcription factor binding to a defined cis element, we show that the transcription factor EBF1 promotes B cell lineage commitment by directly repressing expression of the T-cell-lineage-requisite Gata3 gene. Ebf1-deficient lymphoid progenitors exhibited increased T cell lineage potential and elevated Gata3 transcript expression, whereas enforced EBF1 expression inhibited T cell differentiation and caused rapid loss of Gata3 mRNA. Notably, 6ZFP-mediated perturbation of EBF1 binding to a Gata3 regulatory region restored Gata3 expression, abrogated EBF1-driven suppression of T cell differentiation, and prevented B cell differentiation via a GATA3-dependent mechanism. Furthermore, EBF1 binding to Gata3 regulatory sites induced repressive histone modifications across this region. These data identify a transcriptional circuit critical for B cell lineage commitment.", "title": "Transcriptional Repression of Gata3 Is Essential for Early B Cell Commitment" }, { "docid": "14530534", "text": "Chromatin insulators are DNA elements that regulate the level of gene expression either by preventing gene silencing through the maintenance of heterochromatin boundaries or by preventing gene activation by blocking interactions between enhancers and promoters. CCCTC-binding factor (CTCF), a ubiquitously expressed 11-zinc-finger DNA-binding protein, is the only protein implicated in the establishment of insulators in vertebrates. While CTCF has been implicated in diverse regulatory functions, CTCF has only been studied in a limited number of cell types across human genome. Thus, it is not clear whether the identified cell type-specific differences in CTCF-binding sites are functionally significant. Here, we identify and characterize cell type-specific and ubiquitous CTCF-binding sites in the human genome across 38 cell types designated by the Encyclopedia of DNA Elements (ENCODE) consortium. These cell type-specific and ubiquitous CTCF-binding sites show uniquely versatile transcriptional functions and characteristic chromatin features. In addition, we confirm the insulator barrier function of CTCF-binding and explore the novel function of CTCF in DNA replication. These results represent a critical step toward the comprehensive and systematic understanding of CTCF-dependent insulators and their versatile roles in the human genome.", "title": "Comprehensive Identification and Annotation of Cell Type-Specific and Ubiquitous CTCF-Binding Sites in the Human Genome" }, { "docid": "751192", "text": "BACKGROUND Open chromatin regions are correlated with active regulatory elements in development and are dysregulated in diseases. The BAF (SWI/SNF) complex is essential for development, and has been demonstrated to remodel reconstituted chromatin in vitro and to control the accessibility of a few individual regions in vivo. However, it remains unclear where and how BAF controls the open chromatin landscape to regulate developmental processes, such as human epidermal differentiation. \n RESULTS Using a novel \"on-plate\" ATAC-sequencing approach for profiling open chromatin landscapes with a low number of adherent cells, we demonstrate that the BAF complex is essential for maintaining 11.6 % of open chromatin regions in epidermal differentiation. These BAF-dependent open chromatin regions are highly cell-type-specific and are strongly enriched for binding sites for p63, a master epidermal transcription factor. The DNA sequences of p63 binding sites intrinsically favor nucleosome formation and are inaccessible in other cell types without p63 to prevent ectopic activation. In epidermal cells, BAF and p63 mutually recruit each other to maintain 14,853 open chromatin regions. We further demonstrate that BAF and p63 cooperatively position nucleosomes away from p63 binding sites and recruit transcriptional machinery to control tissue differentiation. \n CONCLUSIONS BAF displays high specificity in controlling the open chromatin landscape during epidermal differentiation by cooperating with the master transcription factor p63 to maintain lineage-specific open chromatin regions.", "title": "A novel ATAC-seq approach reveals lineage-specific reinforcement of the open chromatin landscape via cooperation between BAF and p63" }, { "docid": "2754534", "text": "Cell-selective glucocorticoid receptor (GR) binding to distal regulatory elements is associated with cell type-specific regions of locally accessible chromatin. These regions can either pre-exist in chromatin (pre-programmed) or be induced by the receptor (de novo). Mechanisms that create and maintain these sites are not well understood. We observe a global enrichment of CpG density for pre-programmed elements, and implicate their demethylated state in the maintenance of open chromatin in a tissue-specific manner. In contrast, sites that are actively opened by GR (de novo) are characterized by low CpG density, and form a unique class of enhancers devoid of suppressive effect of agglomerated methyl-cytosines. Furthermore, treatment with glucocorticoids induces rapid changes in methylation levels at selected CpGs within de novo sites. Finally, we identify GR-binding elements with CpGs at critical positions, and show that methylation can affect GR-DNA interactions in vitro. The findings present a unique link between tissue-specific chromatin accessibility, DNA methylation and transcription factor binding and show that DNA methylation can be an integral component of gene regulation by nuclear receptors.", "title": "DNA methylation status predicts cell type-specific enhancer activity." }, { "docid": "3583084", "text": "The conversion of lineage-committed cells to induced pluripotent stem cells (iPSCs) by reprogramming is accompanied by a global remodeling of the epigenome, resulting in altered patterns of gene expression. Here we characterize the transcriptional reorganization of large intergenic non-coding RNAs (lincRNAs) that occurs upon derivation of human iPSCs and identify numerous lincRNAs whose expression is linked to pluripotency. Among these, we defined ten lincRNAs whose expression was elevated in iPSCs compared with embryonic stem cells, suggesting that their activation may promote the emergence of iPSCs. Supporting this, our results indicate that these lincRNAs are direct targets of key pluripotency transcription factors. Using loss-of-function and gain-of-function approaches, we found that one such lincRNA (lincRNA-RoR) modulates reprogramming, thus providing a first demonstration for critical functions of lincRNAs in the derivation of pluripotent stem cells.", "title": "Large intergenic non-coding RNA-RoR modulates reprogramming of human induced pluripotent stem cells" }, { "docid": "24512417", "text": "Induced pluripotent stem cells (iPSCs) can be derived from somatic cells by gene transfer of reprogramming transcription factors. Expression levels of these factors strongly influence the overall efficacy to form iPSC colonies, but additional contribution of stochastic cell-intrinsic factors has been proposed. Here, we present engineered color-coded lentiviral vectors in which codon-optimized reprogramming factors are co-expressed by a strong retroviral promoter that is rapidly silenced in iPSC, and imaged the conversion of fibroblasts to iPSC. We combined fluorescence microscopy with long-term single cell tracking, and used live-cell imaging to analyze the emergence and composition of early iPSC clusters. Applying our engineered lentiviral vectors, we demonstrate that vector silencing typically occurs prior to or simultaneously with the induction of an Oct4-EGFP pluripotency marker. Around 7 days post-transduction (pt), a subfraction of cells in clonal colonies expressed Oct4-EGFP and rapidly expanded. Cell tracking of single cell-derived iPSC colonies supported the concept that stochastic epigenetic changes are necessary for reprogramming. We also found that iPSC colonies may emerge as a genetic mosaic originating from different clusters. Improved vector design with continuous cell tracking thus creates a powerful system to explore the subtle dynamics of biological processes such as early reprogramming events.", "title": "Lentiviral vector design and imaging approaches to visualize the early stages of cellular reprogramming." } ]

[ { "docid": "1974176", "text": "OBJECTIVE To determine whether individual fruits are differentially associated with risk of type 2 diabetes. \n DESIGN Prospective longitudinal cohort study. \n SETTING Health professionals in the United States. \n PARTICIPANTS 66,105 women from the Nurses' Health Study (1984-2008), 85,104 women from the Nurses' Health Study II (1991-2009), and 36,173 men from the Health Professionals Follow-up Study (1986-2008) who were free of major chronic diseases at baseline in these studies. \n MAIN OUTCOME MEASURE Incident cases of type 2 diabetes, identified through self report and confirmed by supplementary questionnaires. \n RESULTS During 3,464,641 person years of follow-up, 12,198 participants developed type 2 diabetes. After adjustment for personal, lifestyle, and dietary risk factors of diabetes, the pooled hazard ratio of type 2 diabetes for every three servings/week of total whole fruit consumption was 0.98 (95% confidence interval 0.97 [corrected] to 0.99). With mutual adjustment of individual fruits, the pooled hazard ratios of type 2 diabetes for every three servings/week were 0.74 (0.66 to 0.83) for blueberries, 0.88 (0.83 to 0.93) for grapes and raisins, 0.89 (0.79 to 1.01) for prunes, 0.93 (0.90 to 0.96) for apples and pears, 0.95 (0.91 to 0.98) for bananas, 0.95 (0.91 to 0.99) for grapefruit, 0.97 (0.92 to 1.02) for peaches, plums, and apricots, 0.99 (0.95 to 1.03) for oranges, 1.03 (0.96 to 1.10) for strawberries, and 1.10 (1.02 to 1.18) for cantaloupe. The pooled hazard ratio for the same increment in fruit juice consumption was 1.08 (1.05 to 1.11). The associations with risk of type 2 diabetes differed significantly among individual fruits (P<0.001 in all cohorts). \n CONCLUSION Our findings suggest the presence of heterogeneity in the associations between individual fruit consumption and risk of type 2 diabetes. Greater consumption of specific whole fruits, particularly blueberries, grapes, and apples, is significantly associated with a lower risk of type 2 diabetes, whereas greater consumption of fruit juice is associated with a higher risk.", "title": "Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies" } ]

[ { "docid": "9822397", "text": "CONTEXT Sugar-sweetened beverages like soft drinks and fruit punches contain large amounts of readily absorbable sugars and may contribute to weight gain and an increased risk of type 2 diabetes, but these relationships have been minimally addressed in adults. \n OBJECTIVE To examine the association between consumption of sugar-sweetened beverages and weight change and risk of type 2 diabetes in women. \n DESIGN, SETTING, AND PARTICIPANTS Prospective cohort analyses conducted from 1991 to 1999 among women in the Nurses' Health Study II. The diabetes analysis included 91,249 women free of diabetes and other major chronic diseases at baseline in 1991. The weight change analysis included 51,603 women for whom complete dietary information and body weight were ascertained in 1991, 1995, and 1999. We identified 741 incident cases of confirmed type 2 diabetes during 716,300 person-years of follow-up. \n MAIN OUTCOME MEASURES Weight gain and incidence of type 2 diabetes. \n RESULTS Those with stable consumption patterns had no difference in weight gain, but weight gain over a 4-year period was highest among women who increased their sugar-sweetened soft drink consumption from 1 or fewer drinks per week to 1 or more drinks per day (multivariate-adjusted means, 4.69 kg for 1991 to 1995 and 4.20 kg for 1995 to 1999) and was smallest among women who decreased their intake (1.34 and 0.15 kg for the 2 periods, respectively) after adjusting for lifestyle and dietary confounders. Increased consumption of fruit punch was also associated with greater weight gain compared with decreased consumption. After adjustment for potential confounders, women consuming 1 or more sugar-sweetened soft drinks per day had a relative risk [RR] of type 2 diabetes of 1.83 (95% confidence interval [CI], 1.42-2.36; P<.001 for trend) compared with those who consumed less than 1 of these beverages per month. Similarly, consumption of fruit punch was associated with increased diabetes risk (RR for > or =1 drink per day compared with <1 drink per month, 2.00; 95% CI, 1.33-3.03; P =.001). \n CONCLUSION Higher consumption of sugar-sweetened beverages is associated with a greater magnitude of weight gain and an increased risk for development of type 2 diabetes in women, possibly by providing excessive calories and large amounts of rapidly absorbable sugars.", "title": "Sugar-sweetened beverages, weight gain, and incidence of type 2 diabetes in young and middle-aged women." }, { "docid": "10071552", "text": "BACKGROUND Taxing sugar-sweetened beverages (SSBs) has been proposed in high-income countries to reduce obesity and type 2 diabetes. We sought to estimate the potential health effects of such a fiscal strategy in the middle-income country of India, where there is heterogeneity in SSB consumption, patterns of substitution between SSBs and other beverages after tax increases, and vast differences in chronic disease risk within the population. \n METHODS AND FINDINGS Using consumption and price variations data from a nationally representative survey of 100,855 Indian households, we first calculated how changes in SSB price alter per capita consumption of SSBs and substitution with other beverages. We then incorporated SSB sales trends, body mass index (BMI), and diabetes incidence data stratified by age, sex, income, and urban/rural residence into a validated microsimulation of caloric consumption, glycemic load, overweight/obesity prevalence, and type 2 diabetes incidence among Indian subpopulations facing a 20% SSB excise tax. The 20% SSB tax was anticipated to reduce overweight and obesity prevalence by 3.0% (95% CI 1.6%-5.9%) and type 2 diabetes incidence by 1.6% (95% CI 1.2%-1.9%) among various Indian subpopulations over the period 2014-2023, if SSB consumption continued to increase linearly in accordance with secular trends. However, acceleration in SSB consumption trends consistent with industry marketing models would be expected to increase the impact efficacy of taxation, averting 4.2% of prevalent overweight/obesity (95% CI 2.5-10.0%) and 2.5% (95% CI 1.0-2.8%) of incident type 2 diabetes from 2014-2023. Given current consumption and BMI distributions, our results suggest the largest relative effect would be expected among young rural men, refuting our a priori hypothesis that urban populations would be isolated beneficiaries of SSB taxation. Key limitations of this estimation approach include the assumption that consumer expenditure behavior from prior years, captured in price elasticities, will reflect future behavior among consumers, and potential underreporting of consumption in dietary recall data used to inform our calculations. \n CONCLUSION Sustained SSB taxation at a high tax rate could mitigate rising obesity and type 2 diabetes in India among both urban and rural subpopulations.", "title": "Averting Obesity and Type 2 Diabetes in India through Sugar-Sweetened Beverage Taxation: An Economic-Epidemiologic Modeling Study" }, { "docid": "6207111", "text": "OBJECTIVES We estimated the relationship between soft drink consumption and obesity and diabetes worldwide. \n METHODS We used multivariate linear regression to estimate the association between soft drink consumption and overweight, obesity, and diabetes prevalence in 75 countries, controlling for other foods (cereals, meats, fruits and vegetables, oils, and total calories), income, urbanization, and aging. Data were obtained from the Euromonitor Global Market Information Database, the World Health Organization, and the International Diabetes Federation. Bottled water consumption, which increased with per-capita income in parallel to soft drink consumption, served as a natural control group. \n RESULTS Soft drink consumption increased globally from 9.5 gallons per person per year in 1997 to 11.4 gallons in 2010. A 1% rise in soft drink consumption was associated with an additional 4.8 overweight adults per 100 (adjusted B; 95% confidence interval [CI] = 3.1, 6.5), 2.3 obese adults per 100 (95% CI = 1.1, 3.5), and 0.3 adults with diabetes per 100 (95% CI = 0.1, 0.8). These findings remained robust in low- and middle-income countries. \n CONCLUSIONS Soft drink consumption is significantly linked to overweight, obesity, and diabetes worldwide, including in low- and middle-income countries.", "title": "Relationship of soft drink consumption to global overweight, obesity, and diabetes: a cross-national analysis of 75 countries." }, { "docid": "32534305", "text": "OBJECTIVE Hyperinsulinemia may promote mammary carcinogenesis. Insulin resistance has been linked to an increased risk of breast cancer and is also characteristic of type 2 diabetes. We prospectively evaluated the association between type 2 diabetes and invasive breast cancer incidence in the Nurses' Health Study. RESEARCH DESIGN AND METHODS A total of 116,488 female nurses who were 30-55 years old and free of cancer in 1976 were followed through 1996 for the occurrence of type 2 diabetes and through 1998 for incident invasive breast cancer, verified by medical records and pathology reports. \n RESULTS During 2.3 million person-years of follow-up, we identified 6,220 women with type 2 diabetes and 5,189 incident cases of invasive breast cancer. Women with type 2 diabetes had a modestly elevated incidence of breast cancer (hazard ratio [HR] = 1.17; 95% CI 1.01-1.35) compared with women without diabetes, independent of age, obesity, family history of breast cancer, history of benign breast disease, reproductive factors, physical activity, and alcohol consumption. This association was apparent among postmenopausal women (1.16; 0.98-1.62) but not premenopausal women (0.83; 0.48-1.42). The association was predominant among women with estrogen receptor-positive breast cancer (1.22; 1.01-1.47). \n CONCLUSIONS Women with type 2 diabetes may have a slightly increased risk of breast cancer.", "title": "Type 2 diabetes and subsequent incidence of breast cancer in the Nurses' Health Study." }, { "docid": "2787558", "text": "BACKGROUND Lifestyle factors including cigarette smoking, alcohol consumption and nutritional habits impact on health, wellness, and the risk of chronic diseases. In the areas of in-vitro fertilization (IVF) and pregnancy, lifestyle factors influence oocyte production, fertilization rates, pregnancy and pregnancy loss, while chronic, low-grade oxidative stress may underlie poor outcomes for some IVF cases. \n METHODS Here, we review the current literature and present some original, previously unpublished data, obtained from couples attending the PIVET Medical Centre in Western Australia. \n RESULTS During the study, 80 % of females and 70 % of male partners completed a 1-week diary documenting their smoking, alcohol and fruit and vegetable intake. The subsequent clinical outcomes of their IVF treatment such as quantity of oocytes collected, fertilization rates, pregnancy and pregnancy loss were submitted to multiple regression analysis, in order to investigate the relationship between patients, treatment and the recorded lifestyle factors. Of significance, it was found that male smoking caused an increased risk of pregnancy loss (p = 0.029), while female smoking caused an adverse effect on ovarian reserve. Both alcohol consumption (β = 0.074, p < 0.001) and fruit and vegetable consumption (β = 0.034, p < 0.001) had positive effects on fertilization. \n CONCLUSION Based on our results and the current literature, there is an important impact of lifestyle factors on IVF clinical outcomes. Currently, there are conflicting results regarding other lifestyle factors such as nutritional habits and alcohol consumption, but it is apparent that chronic oxidative stress induced by lifestyle factors and poor nutritional habits associate with a lower rate of IVF success.", "title": "The effect of cigarette smoking, alcohol consumption and fruit and vegetable consumption on IVF outcomes: a review and presentation of original data" }, { "docid": "15615957", "text": "UNLABELLED Fruit and vegetable consumption has been inversely associated with the risk of chronic diseases including cancer and cardiovascular disease, with the beneficial effects attributed to a variety of protective antioxidants, carotenoids and phytonutrients. The objective of the present study was to determine the effect of supplementation with dehydrated concentrates from mixed fruit and vegetable juices (Juice Plus+R) on serum antioxidant and folate status, plasma homocysteine levels and markers for oxidative stress and DNA damage. Japanese subjects (n=60; age 27.8 yrs; BMI 22.1) were recruited to participate in a double-blind placebo controlled study and were randomized into 2 groups of 30, matched for sex, age, BMI and smoking status (39 males, 22 smokers; 21 females, 13 smokers). Subjects were given encapsulated supplements containing mixed fruit and vegetable juice concentrates or a matching placebo for 28 days, with blood and urine samples collected at baseline, day 14 and day 28 for analytical testing. Compared with the placebo, 28 day supplementation significantly increased the concentration of serum beta-carotene 528% (p<0.0001), lycopene 80.2% (p<0.0005), and alpha tocopherol 39.5% (p<0.0001). Serum folate increased 174.3% (p<0.0001) and correlated with a decrease in plasma homocysteine of -19.9% (p<0.03). Compared with baseline, measures of oxidative stress decreased with serum lipid peroxides declining -10.5% (p<0.02) and urine 8OHdG decreasing -21.1% (p<0.02). Evaluation of data from smokers only (n=17) after 28 days of active supplementation showed comparable changes. \n CONCLUSION In the absence of dietary modification, supplementation with the fruit and vegetable juice concentrate capsules proved to be a highly bioavailable source of phytonutrients. Important antioxidants were elevated to desirable levels associated with decreased risk of disease while markers of oxidative stress were reduced, and folate status improved with a concomitant decrease in homocysteine, and these benefits occurred to a similar extent in smokers when compared to non-smokers.", "title": "Original Article" }, { "docid": "10557471", "text": "The aim of the present investigation was to study the effect of a dietary intervention which combined nutrition information with increased availability of vegetables, fruits and wholegrain bread. The effect of the intervention was determined by changes in the intake of vegetables, fruits, wholegrain bread and estimated nutrients. Furthermore, the study investigated whether changes in relative contribution from different food sources of folate were related to changes in the concentration of plasma total homocysteine (p-tHcy). The 5-month intervention study included 376 male recruits from the Norwegian National Guard, Vaernes (intervention group) and 105 male recruits from the Norwegian National Guard, Heggelia (control group). The study resulted in an increase in the total consumption of vegetables, fruits, berries and juice (P < 0.001) and of wholegrain bread (P < 0.001). The participants in the intervention group showed a higher increase in the intake of dietary fibre (P < 0.001) and folate (P < 0.001) compared with the control group. The relative contribution of folate intake from fruits, vegetables and wholegrain bread was higher in the intervention group compared with the control group (P < 0.001 for all). The increased intake of folate from wholegrain bread was inversely associated with a reduced concentration of p-tHcy (P = 0.017). In summary, the dietary intervention resulted in an increased intake of vegetables, fruits and wholegrain bread and a subsequent increase in folate intake from these food components. Reduction in the concentration of p-tHcy was significantly related to an increased folate intake due to an increased consumption of wholegrain bread.", "title": "Association between folate intake from different food sources in Norway and homocysteine status in a dietary intervention among young male adults." }, { "docid": "13282296", "text": "CONTEXT Although acute hypoglycemia may be associated with cognitive impairment in children with type 1 diabetes, no studies to date have evaluated whether hypoglycemia is a risk factor for dementia in older patients with type 2 diabetes. \n OBJECTIVE To determine if hypoglycemic episodes severe enough to require hospitalization are associated with an increased risk of dementia in a population of older patients with type 2 diabetes followed up for 27 years. \n DESIGN, SETTING, AND PATIENTS A longitudinal cohort study from 1980-2007 of 16,667 patients with a mean age of 65 years and type 2 diabetes who are members of an integrated health care delivery system in northern California. \n MAIN OUTCOME MEASURE Hypoglycemic events from 1980-2002 were collected and reviewed using hospital discharge and emergency department diagnoses. Cohort members with no prior diagnoses of dementia, mild cognitive impairment, or general memory complaints as of January 1, 2003, were followed up for a dementia diagnosis through January 15, 2007. Dementia risk was examined using Cox proportional hazard regression models, adjusted for age, sex, race/ethnicity, education, body mass index, duration of diabetes, 7-year mean glycated hemoglobin, diabetes treatment, duration of insulin use, hyperlipidemia, hypertension, cardiovascular disease, stroke, transient cerebral ischemia, and end-stage renal disease. \n RESULTS At least 1 episode of hypoglycemia was diagnosed in 1465 patients (8.8%) and dementia was diagnosed in 1822 patients (11%) during follow-up; 250 patients had both dementia and at least 1 episode of hypoglycemia (16.95%). Compared with patients with no hypoglycemia, patients with single or multiple episodes had a graded increase in risk with fully adjusted hazard ratios (HRs): for 1 episode (HR, 1.26; 95% confidence interval [CI], 1.10-1.49); 2 episodes (HR, 1.80; 95% CI, 1.37-2.36); and 3 or more episodes (HR, 1.94; 95% CI, 1.42-2.64). The attributable risk of dementia between individuals with and without a history of hypoglycemia was 2.39% per year (95% CI, 1.72%-3.01%). Results were not attenuated when medical utilization rates, length of health plan membership, or time since initial diabetes diagnosis were added to the model. When examining emergency department admissions for hypoglycemia for association with risk of dementia (535 episodes), results were similar (compared with patients with 0 episodes) with fully adjusted HRs: for 1 episode (HR, 1.42; 95% CI, 1.12-1.78) and for 2 or more episodes (HR, 2.36; 95% CI, 1.57-3.55). \n CONCLUSIONS Among older patients with type 2 diabetes, a history of severe hypoglycemic episodes was associated with a greater risk of dementia. Whether minor hypoglycemic episodes increase risk of dementia is unknown.", "title": "Hypoglycemic episodes and risk of dementia in older patients with type 2 diabetes mellitus." }, { "docid": "31229233", "text": "BACKGROUND Patients with type 2 diabetes have a 40% increased risk of bladder cancer. Thiazolidinediones, especially pioglitazone, may increase the risk. We conducted a systematic review and meta-analysis to evaluate the risk of bladder cancer among adults with type 2 diabetes taking thiazolidinediones. \n METHODS We searched key biomedical databases (including MEDLINE, Embase and Scopus) and sources of grey literature from inception through March 2012 for published and unpublished studies, without language restrictions. We included randomized controlled trials (RCTs), cohort studies and case-control studies that reported incident bladder cancer among people with type 2 diabetes who ever (v. never) were exposed to pioglitazone (main outcome), rosiglitazone or any thiazolidinedione. \n RESULTS Of the 1787 studies identified, we selected 4 RCTs, 5 cohort studies and 1 case-control study. The total number of patients was 2,657,365, of whom 3643 had newly diagnosed bladder cancer, for an overall incidence of 53.1 per 100,000 person-years. The one RCT that reported on pioglitazone use found no significant association with bladder cancer (risk ratio [RR] 2.36, 95% confidence interval [CI] 0.91-6.13). The cohort studies of thiazolidinediones (pooled RR 1.15, 95% CI 1.04-1.26; I(2) = 0%) and of pioglitazone specifically (pooled RR 1.22, 95% CI 1.07-1.39; I(2) = 0%) showed significant associations with bladder cancer. No significant association with bladder cancer was observed in the two RCTs that evaluated rosiglitazone use (pooled RR 0.87, 95% CI 0.34-2.23; I(2) = 0%). \n INTERPRETATION The limited evidence available supports the hypothesis that thiazolidinediones, particularly pioglitazone, are associated with an increased risk of bladder cancer among adults with type 2 diabetes.", "title": "Use of thiazolidinediones and the risk of bladder cancer among people with type 2 diabetes: a meta-analysis." }, { "docid": "4886637", "text": "Incidences of breast cancer, type 2 diabetes, and metabolic syndrome have increased over the past decades with the obesity epidemic, especially in industrialized countries. Insulin resistance, hyperinsulinemia, and changes in the signaling of growth hormones and steroid hormones associated with diabetes may affect the risk of breast cancer. We reviewed epidemiologic studies of the association between type 2 diabetes and risk of breast cancer and the available evidence on the role of hormonal mediators of an association between diabetes and breast cancer. The combined evidence supports a modest association between type 2 diabetes and the risk of breast cancer, which appears to be more consistent among postmenopausal than among premenopausal women. Despite many proposed potential pathways, the mechanisms underlying an association between diabetes and breast cancer risk remain unclear, particularly because the 2 diseases share several risk factors, including obesity, a sedentary lifestyle, and possibly intake of saturated fat and refined carbohydrates, that may confound this association. Although the metabolic syndrome is closely related to diabetes and embraces additional components that might influence breast cancer risk, the role of the metabolic syndrome in breast carcinogenesis has not been studied and thus remains unknown.", "title": "Diabetes, metabolic syndrome, and breast cancer: a review of the current evidence." }, { "docid": "11071351", "text": "The National High Blood Pressure Education Program Coordinating Committee published its first statement on the primary prevention of hypertension in 1993. This article updates the 1993 report, using new and further evidence from the scientific literature. Current recommendations for primary prevention of hypertension involve a population-based approach and an intensive targeted strategy focused on individuals at high risk for hypertension. These 2 strategies are complementary and emphasize 6 approaches with proven efficacy for prevention of hypertension: engage in moderate physical activity; maintain normal body weight; limit alcohol consumption; reduce sodium intake; maintain adequate intake of potassium; and consume a diet rich in fruits, vegetables, and low-fat dairy products and reduced in saturated and total fat. Applying these approaches to the general population as a component of public health and clinical practice can help prevent blood pressure from increasing and can help decrease elevated blood pressure levels for those with high normal blood pressure or hypertension.", "title": "Primary prevention of hypertension: clinical and public health advisory from The National High Blood Pressure Education Program." }, { "docid": "30983338", "text": "AIMS/HYPOTHESIS We assessed the association between congenital malformations and maternal hyperglycemia in pregnant women with pregestational (type 1 or type 2) diabetes and investigated if the rate of congenital malformations was similar in women with near-normal glycemic control compared to the background population. We also assessed the association between congenital malformations and maternal hyperglycemia in pregnant women with pregestational diabetes with special focus on women with near-normal HbA1c in early pregnancy. MATERIALS AND METHODS This is a literature review based on an electronic literature search of the databases PubMed, Cochrane, Embase and Web of Science conducted in July 2017 using the search terms diabetes, pregnancy, HbA1c or glycemic control and congenital anomaly or congenital anomaly. We included original papers in English published after 1997 with data on congenital malformations and HbA1c in at least 250 women with pregestational diabetes. \n RESULTS Nine papers with in total 6225 women with type 1 diabetes and 2334 women with type 2 diabetes were included. The prevalence of congenital malformations was 6.4% in women with type 1 diabetes and 4.3% in women with type 2 diabetes and for the combined group of women with pregestational diabetes, the relative risk compared to the background population was 3.2. In women with HbA1c < 53 mmol/mol (7.0%) in early pregnancy or HbA1c 53-64 mmol/mol (7.0-8.0%) the prevalence of congenital malformations was 4.3 and 3.7%, respectively, with a relative risk of 2.2 and 1.9, respectively. \n CONCLUSIONS In pregnant women with pregestational diabetes the prevalence of congenital abnormalities was threefold higher in women with pregestational diabetes compared to the background population. However, HbA1c below 53 mmol/mol (7.0%) in early pregnancy was also associated with a two times increased risk of congenital malformations compared to the background population.", "title": "The prevalence of congenital malformations is still higher in pregnant women with pregestational diabetes despite near-normal HbA1c: a literature review." }, { "docid": "32850528", "text": "OBJECTIVE To evaluate serum amylase and lipase levels and the rate of acute pancreatitis in patients with type 2 diabetes and high cardiovascular risk randomized to liraglutide or placebo and observed for 3.5-5.0 years. RESEARCH DESIGN AND METHODS A total of 9,340 patients with type 2 diabetes were randomized to either liraglutide or placebo (median observation time 3.84 years). Fasting serum lipase and amylase were monitored. Acute pancreatitis was adjudicated in a blinded manner. \n RESULTS Compared with the placebo group, liraglutide-treated patients had increases in serum lipase and amylase of 28.0% and 7.0%, respectively. Levels were increased at 6 months and then remained stable. During the study, 18 (0.4% [1.1 events/1,000 patient-years of observation] [PYO]) liraglutide-treated and 23 (0.5% [1.7 events/1,000 PYO]) placebo patients had acute pancreatitis confirmed by adjudication. Most acute pancreatitis cases occurred ≥12 months after randomization. Liraglutide-treated patients with prior history of pancreatitis (n = 147) were not more likely to develop acute pancreatitis than similar patients in the placebo group (n = 120). Elevations of amylase and lipase levels did not predict future risk of acute pancreatitis (positive predictive value <1.0%) in patients treated with liraglutide. \n CONCLUSIONS In a population with type 2 diabetes at high cardiovascular risk, there were numerically fewer events of acute pancreatitis among liraglutide-treated patients (regardless of previous history of pancreatitis) compared with the placebo group. Liraglutide was associated with increases in serum lipase and amylase, which were not predictive of an event of subsequent acute pancreatitis.", "title": "Amylase, Lipase, and Acute Pancreatitis in People With Type 2 Diabetes Treated With Liraglutide: Results From the LEADER Randomized Trial." }, { "docid": "120626", "text": "Obesity is associated with an increased risk of developing insulin resistance and type 2 diabetes. In obese individuals, adipose tissue releases increased amounts of non-esterified fatty acids, glycerol, hormones, pro-inflammatory cytokines and other factors that are involved in the development of insulin resistance. When insulin resistance is accompanied by dysfunction of pancreatic islet β-cells — the cells that release insulin — failure to control blood glucose levels results. Abnormalities in β-cell function are therefore critical in defining the risk and development of type 2 diabetes. This knowledge is fostering exploration of the molecular and genetic basis of the disease and new approaches to its treatment and prevention.", "title": "Mechanisms linking obesity to insulin resistance and type 2 diabetes" }, { "docid": "1568684", "text": "The interest in brown adipose tissue (BAT) as a target to combat metabolic disease has recently been renewed with the discovery of functional BAT in humans. In rodents, BAT can be activated by bile acids, which activate type 2 iodothyronine deiodinase (D2) in BAT via the G-coupled protein receptor TGR5, resulting in increased oxygen consumption and energy expenditure. Here we examined the effects of oral supplementation of the bile acid chenodeoxycholic acid (CDCA) on human BAT activity. Treatment of 12 healthy female subjects with CDCA for 2 days resulted in increased BAT activity. Whole-body energy expenditure was also increased upon CDCA treatment. In vitro treatment of primary human brown adipocytes derived with CDCA or specific TGR5 agonists increased mitochondrial uncoupling and D2 expression, an effect that was absent in human primary white adipocytes. These findings identify bile acids as a target to activate BAT in humans.", "title": "The Bile Acid Chenodeoxycholic Acid Increases Human Brown Adipose Tissue Activity." }, { "docid": "2138843", "text": "Diabetes is a group of chronic diseases characterized by hyperglycemia. Modern medical care uses a vast array of lifestyle and pharmaceutical interventions aimed at preventing and controlling hyperglycemia. In addition to ensuring the adequate delivery of glucose to the tissues of the body, treatment of diabetes attempts to decrease the likelihood that the tissues of the body are harmed by hyperglycemia. The importance of protecting the body from hyperglycemia cannot be overstated; the direct and indirect effects on the human vascular tree are the major source of morbidity and mortality in both type 1 and type 2 diabetes. Generally, the injurious effects of hyperglycemia are separated into macrovascular complications (coronary artery disease, peripheral arterial disease, and stroke) and microvascular complications (diabetic nephropathy, neuropathy, and retinopathy). It is important for physicians to understand the relationship between diabetes and vascular disease because the prevalence of diabetes continues to increase in the United States, and the clinical armamentarium for primary and secondary prevention of these complications is also expanding. ### Diabetic retinopathy Diabetic retinopathy may be the most common microvascular complication of diabetes. It is responsible for ∼ 10,000 new cases of blindness every year in the United States alone.1 The risk of developing diabetic retinopathy or other microvascular complications of diabetes depends on both the duration and the severity of hyperglycemia. Development of diabetic retinopathy in patients with type 2 diabetes was found to be related to both severity of hyperglycemia and presence of hypertension in the U.K. Prospective Diabetes Study (UKPDS), and most patients with type 1 diabetes develop evidence of retinopathy within 20 years of diagnosis.2,3 Retinopathy may begin to develop as early as 7 years before the diagnosis of diabetes in patients with type 2 diabetes.1 There are several proposed pathological mechanisms by which diabetes may lead …", "title": "Microvascular and Macrovascular Complications of Diabetes" }, { "docid": "8842332", "text": "OBJECTIVE To compare contemporary pregnancy outcomes in women with and without type 1 diabetes, and to examine the effects of obesity and glycaemic control on these outcomes. \n DESIGN AND SETTING Historical cohort study in a specialist diabetes and maternity network in Victoria. \n PARTICIPANTS All singleton births (at least 20 weeks' gestation), 2010-2013, were analysed: 107 pregnancies to women with type 1 diabetes and 27 075 pregnancies to women without diabetes. Women with type 2 diabetes or gestational diabetes were excluded. \n METHODS Data were extracted from the Birthing Outcomes System database; associations between type 1 diabetes and pregnancy outcomes were analysed by multivariable regression. \n MAIN OUTCOME MEASURES Mode of birth; maternal and neonatal outcomes. \n RESULTS The mean body mass index was higher for women with type 1 diabetes than for women without diabetes (mean, 27.3 kg/m(2) [SD, 5.0] v 25.7 kg/m(2) [SD, 5.9]; P = 0.01); the median gestation period for their babies was shorter (median, 37.3 weeks [IQR, 34.6-38.1] v 39.4 weeks [IQR, 38.4-40.4]; P < 0.001) and they were more likely to be large for gestational age (LGA) (adjusted odds ratio [aOR], 7.9; 95% CI, 5.3-11.8). Women with type 1 diabetes were more likely to have had labour induced (aOR, 3.0; 95% CI, 2.0-4.5), a caesarean delivery (aOR, 4.6; 95% CI, 3.1-7.0), or a pre-term birth (aOR, 6.7; 95% CI, 4.5-10.0); their babies were more likely to have shoulder dystocia (aOR, 8.2; 95% CI, 3.6-18.7), hypoglycaemia (aOR, 10.3; 95% CI, 6.8-15.6), jaundice (aOR, 5.1; 95% CI, 3.3-7.7), respiratory distress (aOR, 2.5; 95% CI, 1.4-4.4) or to suffer perinatal death (aOR, 4.3; 95% CI, 1.9-9.9). In women with type 1 diabetes, greater obesity was associated with increased odds for an LGA baby or congenital malformation, and increased HbA1c levels were associated with pre-term birth and perinatal death. \n CONCLUSION Women with type 1 diabetes, even when managed in a specialist setting, still experience adverse obstetric and neonatal outcomes. Poor glycaemic control is not wholly responsible for adverse outcomes, reinforcing the importance of other risk factors, such as obesity and weight gain.", "title": "Contemporary type 1 diabetes pregnancy outcomes: impact of obesity and glycaemic control." }, { "docid": "13619127", "text": "OBJECTIVE To assess the risks of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia in patients with type 2 diabetes associated with prescribed diabetes drugs, particularly newer agents including gliptins or glitazones (thiazolidinediones). \n DESIGN Open cohort study in primary care. \n SETTING 1243 practices contributing data to the QResearch database in England. \n PARTICIPANTS 469,688 patients with type 2 diabetes aged 25-84 years between 1 April 2007 and 31 January 2015. EXPOSURES Hypoglycaemic agents (glitazones, gliptins, metformin, sulphonylureas, insulin, and other) alone and in combination. \n MAIN OUTCOME MEASURES First recorded diagnoses of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia recorded on patients' primary care, mortality, or hospital records. Cox models estimated hazard ratios for diabetes treatments adjusting for potential confounders. \n RESULTS 21,308 (4.5%) and 32,533 (6.9%) patients received prescriptions for glitazones and gliptins during follow-up, respectively. Compared with non-use, glitazones were associated with a decreased risk of blindness (adjusted hazard ratio 0.71, 95% confidence interval 0.57 to 0.89; rate 14.4 per 10,000 person years of exposure) and an increased risk of hypoglycaemia (1.22, 1.10 to 1.37; 65.1); gliptins were associated with a decreased risk of hypoglycaemia (0.86, 0.77 to 0.96; 45.8). Although the numbers of patients prescribed gliptin monotherapy or glitazones monotherapy were relatively low, there were significantly increased risks of severe kidney failure compared with metformin monotherapy (adjusted hazard ratio 2.55, 95% confidence interval 1.13 to 5.74). We found significantly lower risks of hyperglycaemia among patients prescribed dual therapy involving metformin with either gliptins (0.78, 0.62 to 0.97) or glitazones (0.60, 0.45 to 0.80) compared with metformin monotherapy. Patients prescribed triple therapy with metformin, sulphonylureas, and either gliptins (adjusted hazard ratio 5.07, 95% confidence interval 4.28 to 6.00) or glitazones (6.32, 5.35 to 7.45) had significantly higher risks of hypoglycaemia than those prescribed metformin monotherapy, but these risks were similar to those involving dual therapy with metformin and sulphonylureas (6.03, 5.47 to 6.63). Patients prescribed triple therapy with metformin, sulphonylureas, and glitazones had a significantly reduced risk of blindness compared with metformin monotherapy (0.67, 0.48 to 0.94). \n CONCLUSIONS We have found lower risks of hyperglycaemia among patients prescribed dual therapy involving metformin with either gliptins or glitazones compared with metformin alone. Compared with metformin monotherapy, triple therapy with metformin, sulphonylureas, and either gliptins or glitazones was associated with an increased risk of hypoglycaemia, which was similar to the risk for dual therapy with metformin and sulphonylureas. Compared with metformin monotherapy, triple therapy with metformin, sulphonylureas, and glitazones was associated with a reduced risk of blindness. These results, while subject to residual confounding, could have implications for the prescribing of hypoglycaemic drugs.", "title": "Diabetes treatments and risk of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia: open cohort study in primary care" }, { "docid": "27449472", "text": "The metabolic syndrome was initially described as an insulin-resistance syndrome characterized by the clustering of metabolic traits such as high triglycerides, low high-density lipoprotein cholesterol, high blood pressure, abdominal obesity and different degrees of impaired glucose regulation. Although different definitions have been developed by various consensus groups, epidemiological studies demonstrate that they all associate the metabolic syndrome with a similar cardiometabolic risk, which is high for diabetes (ranging between three- and 20-fold), depending on the number of components and the inclusion of impaired fasting glucose, impaired glucose tolerance or both. The latter appear to indicate the failure of the beta cell to produce enough insulin to compensate for the increased demand due to insulin resistance. There is a hyperbolic relationship between insulin production and insulin sensitivity, which can be calculated by the disposition index. When this is altered there is a higher risk of developing Type 2 diabetes. There have been no clinical trials in subjects selected by the diagnosis of metabolic syndrome, but structured lifestyle changes have been tested in people with impaired fasting glucose/impaired glucose tolerance and have been able to reduce incident Type 2 diabetes by almost 50%, as long as a weight loss of at least 5% is achieved. Oral antidiabetic and anti-obesity drugs have also been successful to a lesser degree. Some fibrates have reduced or delayed incident diabetes. Extended-release niacin has a neutral effect and statins are controversial. ACE inhibitors and ARBs are the antihypertensive agents least associated with incident diabetes.", "title": "Metabolic syndrome as a risk factor for diabetes." } ]

[ { "docid": "5548081", "text": "CONTEXT Some studies have inferred that an epidemic of Kaposi sarcoma-associated herpesvirus (KSHV) infection in homosexual men in the United States occurred concurrently with that of human immunodeficiency virus (HIV), but there have been no direct measurements of KSHV prevalence at the beginning of the HIV epidemic. \n OBJECTIVES To determine the prevalence of KSHV infection in homosexual men in San Francisco, Calif, at the beginning of the HIV epidemic in 1978 and 1979 and to examine changes in prevalence of KSHV at time points from 1978 through 1996 in light of changes in sexual behavior. \n DESIGN, SETTING, AND PARTICIPANTS Analysis of a clinic-based sample (n = 398) derived from the San Francisco City Clinic Cohort (ages 18-66 years) (n = 2666 for analyses herein) and from population-based samples from the San Francisco Men's Health Study (MHS) (ages 25-54 years) (n = 825 and 252) and the San Francisco Young Men's Health Study (YMHS) (ages 18-29 years) (n = 428-976, and 557); behavioral studies were longitudinal and KSHV prevalence studies were cross-sectional. \n MAIN OUTCOME MEASURES Antibodies against KSHV and HIV; sexual behaviors. \n RESULTS The prevalence of KSHV infection in 1978 and 1979 was 26.5% of 235 (a random sample) overall (weighted for HIV infection) vs 6.9% (128/1842) for HIV in the San Francisco City Clinic Cohort sample. The prevalence of KSHV infection remained essentially unchanged between an MHS sample of 252 in 1984 and 1985 (29.6%) and a YMHS sample of 557 in 1995 and 1996 (26.4%), while HIV prevalence dropped from 49.5% of 825 in 1984 and 1985 (MHS) to 17.6% of 428 in 1992 and 1993 (YMHS). The proportion of men practicing unprotected receptive anal intercourse with 1 or more partners declined from 54% to 11% during the 1984 through 1993 period (MHS) with similar though slightly higher values in the YMHS in 1992 and 1993; whereas for unprotected oral intercourse it ranged between 60% and 90% in the 1984 through 1996 period (MHS and YMHS). \n CONCLUSIONS Infection with KSHV was already highly prevalent in homosexual men when the HIV epidemic began in San Francisco, and its prevalence has been maintained at a nearly constant level. Any declines in the incidence of Kaposi sarcoma do not appear to be caused by a decline in KSHV transmission.", "title": "Prevalence of Kaposi sarcoma-associated herpesvirus infection in homosexual men at beginning of and during the HIV epidemic." } ]

[ { "docid": "21216726", "text": "Little is known about the epidemiology of human herpesvirus 8 (HHV-8) infections among women. A cross-sectional study was conducted of HHV-8 infection among human immunodeficiency virus (HIV)-infected and high-risk HIV-uninfected women. Serological tests with noninduced (latent) and induced (lytic) HHV-8 antigens were used to detect infection among 2483 participants of a multisite cohort. Reactivity to latent antigen was present in 4.1% and to induced antigens in 12.0% of women. Seven of 8 women who reported Kaposi's sarcoma had HHV-8 antibodies. Among HIV-positive women, HHV-8 infection was associated with use of crack, cocaine, or heroin (76% vs. 65%; P<.001), past syphilis (29% vs. 20%; P<.001), an injection drug-using male sex partner (61% vs. 53%; P=.014), black race (P=.010), and enrollment site (P=.015). In multivariate analysis, HIV infection, older age, past syphilis, black race, and enrollment site were independently associated with HHV-8 infection. In this cohort of North American women, HHV-8 infection was associated with HIV infection, drug use, and risky sexual behavior.", "title": "Human herpesvirus 8 infection and Kaposi's sarcoma among human immunodeficiency virus-infected and -uninfected women." }, { "docid": "21859699", "text": "Providing transplantation opportunities for patients with incompatible live donors through kidney paired donation (KPD) is seen as one of the important strategies for easing the crisis in organ availability. It has been estimated that an additional 1000-2000 transplants per year could be accomplished if a national KPD program were implemented in the United States. While most of these transplants could be arranged within the participants' local or regional area, patients with hard-to-match blood types or broad HLA sensitization would benefit from matching across larger geographic areas. In this case, either patients or organs would need to travel in order to obtain maximum benefit from a national program. In this study, we describe how a triple KPD enabled a highly sensitized patient (PRA 96%) to receive a well-matched kidney from a live donor on the opposite coast. The kidney was removed in San Francisco and transported to Baltimore where it was reperfused 8 h later. The patient had prompt function and 1 year later has a serum creatinine of 1.1 mg/dl. This case provides a blueprint for solving some of the complexities that are inherent in the implementation of a national KPD program in a large country like the United States.", "title": "Successful three-way kidney paired donation with cross-country live donor allograft transport." }, { "docid": "22309946", "text": "BACKGROUND Technological advancements in neuroimaging and the increased use of these diagnostic modalities are responsible for the discovery of incidentally identified anomalies within the CNS. In addition to the identification of unanticipated brain MRI abnormalities suggestive of demyelinating disease in patients undergoing neuroimaging for a medical reason other than evaluation for multiple sclerosis (MS), asymptomatic spinal cord lesions are periodically identified. \n OBJECTIVE To determine if asymptomatic spinal cord lesions are associated with clinical progression in subjects with radiologically isolated syndrome (RIS). \n METHODS A retrospective review of RIS cases at the University of California, San Francisco Multiple Sclerosis Center was performed. The presence of asymptomatic cervical spinal cord MRI lesions was analyzed as a potential predictor for clinical progression. \n RESULTS Twenty-five of 71 subjects with RIS possessed findings within the cervical spine that were highly suggestive of demyelinating disease. Of these subjects, 21 (84%) progressed clinically to clinically isolated syndrome (n = 19) or primary progressive multiple sclerosis (n = 2) over a median time of 1.6 years from the date of RIS identification (interquartile range 0.8-3.8). The sensitivity, specificity, and positive predictive value of an asymptomatic spinal cord lesion for subsequent development of either a first demyelinating attack or primary progressive MS were 87.5%, 91.5%, and 84%, respectively. The odds ratio of clinical progression was 75.3 (95% confidence interval 16.1-350.0, p < 0.0001). This association remained significant after adjusting for potential confounders. \n CONCLUSION These findings suggest that the presence of asymptomatic spinal cord lesions place subjects with RIS at substantial risk for clinical conversion to either an acute or progressive event, a risk that is independent of brain lesions on MRI.", "title": "Asymptomatic spinal cord lesions predict disease progression in radiologically isolated syndrome." }, { "docid": "22194407", "text": "This paper seeks to establish the strength of association between contemporary tuberculosis (TB) in England and Wales and several potential aetiological factors. It presents an ecological analysis of standardised annual TB mortality rates for the 403 local authority districts between 1982 and 1992, disaggregated by age and sex. Social, demographic and ethnicity measures from the 1981 and 1991 censuses and standardised annual AIDS-related mortality rates for young men are used to calculate Poisson regression models. A strong association was found between all TB mortality groups and overcrowding at the household level. For women, no other measures improved the explanatory power of the models. In multiple regressions, both poverty and AIDS-related mortality explained additional variation in the model for younger men. The link between ethnicity and tuberculosis notifications was not reflected in this analysis of mortality. For all groups no evidence of a positive relationship with ethnicity was found, once overcrowding had been accounted for. The significance of household as opposed to district level crowding suggests that prolonged contact is required for disease transmission. Regression analysis indicates that it is the overcrowding and poverty among ethnic populations that is significant for their tuberculosis mortality. The fact that the relationship between AIDS and TB is confined to the group most typical of AIDS patients provides evidence that AIDS has little influence on the level of tuberculosis mortality in the wider population. Explanations for the observed relationship include preferential certification, migration for treatment and shortcomings in health care provision.", "title": "Tuberculosis mortality in England and Wales during 1982-1992: its association with poverty, ethnicity and AIDS." }, { "docid": "9539248", "text": "Mosquito-borne viruses cause significant levels of morbidity and mortality in humans and domesticated animals. Maintenance of mosquito-borne viruses in nature requires a biological transmission cycle that involves alternating virus replication in a susceptible vertebrate and mosquito host. Although the vertebrate infection is acute and often associated with disease, continual transmission of these viruses in nature depends on the establishment of a persistent, nonpathogenic infection in the mosquito vector. An antiviral RNAi response has been shown to limit the replication of RNA viruses in flies. However, the importance of the RNAi pathway as an antiviral defense in mammals is unclear. Differences in the immune responses of mammals and mosquitoes may explain why these viruses are not generally associated with pathology in the invertebrate host. We identified virus-derived small interfering RNAs (viRNAs), 21 nt in length, in Aedes aegypti infected with the mosquito-borne virus, Sindbis (SINV). viRNAs had an asymmetric distribution that spanned the length of the SINV genome. To determine the role of viRNAs in controlling pathogenic potential, mosquitoes were infected with recombinant alphaviruses expressing suppressors of RNA silencing. Decreased survival was observed in mosquitoes in which the accumulation of viRNAs was suppressed. These results suggest that an exogenous siRNA pathway is essential to the survival of mosquitoes infected with alphaviruses and, thus, the maintenance of these viruses in nature.", "title": "Alphavirus-derived small RNAs modulate pathogenesis in disease vector mosquitoes." }, { "docid": "44640124", "text": "SIGNIFICANCE The extracellular matrix (ECM) fulfills essential functions in multicellular organisms. It provides the mechanical scaffold and environmental cues to cells. Upon cell attachment, the ECM signals into the cells. In this process, reactive oxygen species (ROS) are physiologically used as signalizing molecules. RECENT ADVANCES ECM attachment influences the ROS-production of cells. In turn, ROS affect the production, assembly and turnover of the ECM during wound healing and matrix remodeling. Pathological changes of ROS levels lead to excess ECM production and increased tissue contraction in fibrotic disorders and desmoplastic tumors. Integrins are cell adhesion molecules which mediate cell adhesion and force transmission between cells and the ECM. They have been identified as a target of redox-regulation by ROS. Cysteine-based redox-modifications, together with structural data, highlighted particular regions within integrin heterodimers that may be subject to redox-dependent conformational changes along with an alteration of integrin binding activity. CRITICAL ISSUES In a molecular model, a long-range disulfide-bridge within the integrin β-subunit and disulfide bridges within the genu and calf-2 domains of the integrin α-subunit may control the transition between the bent/inactive and upright/active conformation of the integrin ectodomain. These thiol-based intramolecular cross-linkages occur in the stalk domain of both integrin subunits, whereas the ligand-binding integrin headpiece is apparently unaffected by redox-regulation. FUTURE DIRECTIONS Redox-regulation of the integrin activation state may explain the effect of ROS in physiological processes. A deeper understanding of the underlying mechanism may open new prospects for the treatment of fibrotic disorders.", "title": "Redox-relevant aspects of the extracellular matrix and its cellular contacts via integrins." }, { "docid": "708425", "text": "HIV continues to spread globally, mainly through sexual contact. Despite advances in treatment and care, preventing transmission with vaccines or microbicides has proven difficult. A promising strategy to avoid transmission is prophylactic treatment with antiretroviral drugs before exposure to HIV. Clinical trials evaluating the efficacy of daily treatment with the reverse transcriptase inhibitors tenofovir disoproxil fumarate (TDF) or Truvada (TDF plus emtricitabine) are under way. We hypothesized that intermittent prophylactic treatment with long-acting antiviral drugs would be as effective as daily dosing in blocking the earliest stages of viral replication and preventing mucosal transmission. We tested this hypothesis by intermittently giving prophylactic Truvada to macaque monkeys and then exposing them rectally to simian-human immunodeficiency virus (SHIV) once a week for 14 weeks. A simple regimen with an oral dose of Truvada given 1, 3, or 7 days before exposure followed by a second dose 2 hours after exposure was as protective as daily drug administration, possibly because of the long intracellular persistence of the drugs. In addition, a two-dose regimen initiated 2 hours before or after virus exposure was effective, and full protection was obtained by doubling the Truvada concentration in both doses. We saw no protection if the first dose was delayed until 24 hours after exposure, underscoring the importance of blocking initial replication in the mucosa. Our results show that intermittent prophylactic treatment with an antiviral drug can be highly effective in preventing SHIV infection, with a wide window of protection. They strengthen the possibility of developing feasible, cost-effective strategies to prevent HIV transmission in humans.", "title": "Intermittent prophylaxis with oral truvada protects macaques from rectal SHIV infection." }, { "docid": "596817", "text": "From Darwin's study of the Galapagos and Wallace's study of Indonesia, islands have played an important role in evolutionary investigations, and radiations within archipelagos are readily interpreted as supporting the conventional view of allopatric speciation. Even during the ongoing paradigm shift towards other modes of speciation, island radiations, such as the Lesser Antillean anoles, are thought to exemplify this process. Geological and molecular phylogenetic evidence show that, in this archipelago, Martinique anoles provide several examples of secondary contact of island species. Four precursor island species, with up to 8 mybp divergence, met when their islands coalesced to form the current island of Martinique. Moreover, adjacent anole populations also show marked adaptation to distinct habitat zonation, allowing both allopatric and ecological speciation to be tested in this system. We take advantage of this opportunity of replicated island coalescence and independent ecological adaptation to carry out an extensive population genetic study of hypervariable neutral nuclear markers to show that even after these very substantial periods of spatial isolation these putative allospecies show less reproductive isolation than conspecific populations in adjacent habitats in all three cases of subsequent island coalescence. The degree of genetic interchange shows that while there is always a significant genetic signature of past allopatry, and this may be quite strong if the selection regime allows, there is no case of complete allopatric speciation, in spite of the strong primae facie case for it. Importantly there is greater genetic isolation across the xeric/rainforest ecotone than is associated with any secondary contact. This rejects the development of reproductive isolation in allopatric divergence, but supports the potential for ecological speciation, even though full speciation has not been achieved in this case. It also explains the paucity of anole species in the Lesser Antilles compared to the Greater Antilles.", "title": "Genetic Tests for Ecological and Allopatric Speciation in Anoles on an Island Archipelago" }, { "docid": "84884645", "text": "Preface 1. Historical introduction 2. Breeding biology of marsupials by family 3. Sexual differentiation and development 4. Male anatomy and spermatogenesis 5. The female urogenital tract and oogenesis 6. Ovarian function and control 7. Pregnancy and parturition 8. Lactation 9. Neuroendocrine control of seasonal breeding 10. Marsupials and the evolution of mammalian reproduction References Index.", "title": "Reproductive physiology of marsupials" }, { "docid": "27063470", "text": "OBJECTIVE To identify changes in the occurrence of Creutzfeldt-Jakob disease that might be related to the epidemic of bovine spongiform encephalopathy. \n DESIGN Epidemiological surveillance of the United Kingdom population for Creutzfeldt-Jakob disease based on (a) referral of suspected cases by neurologists, neuropathologists, and neurophysiologists and (b) death certificates. \n SETTING England and Wales during 1970-84, and whole of the United Kingdom during 1985-96. SUBJECTS All 662 patients identified as sporadic cases of Creutzfeldt-Jakob disease. \n MAIN OUTCOME MEASURES Age distribution of patients, age specific time trends of disease, occupational exposure to cattle, potential exposure to causative agent of bovine spongiform encephalopathy. \n RESULTS During 1970-96 there was an increase in the number of sporadic cases of Creutzfeldt-Jakob disease recorded yearly in England and Wales. The greatest increase was among people aged over 70. There was a statistically significant excess of cases among dairy farm workers and their spouses and among people at increased risk of contact with live cattle infected with bovine spongiform encephalopathy. During 1994-6 there were six deaths from sporadic Creutzfeldt-Jakob disease in the United Kingdom in patients aged under 30. \n CONCLUSIONS The increase in the incidence of sporadic Creutzfeldt-Jakob disease and the high incidence in dairy farmers in the United Kingdom may be unrelated to bovine spongiform encephalopathy. The most striking change in the pattern of Creutzfeldt-Jakob disease in the United Kingdom after the epidemic of bovine spongiform encephalopathy is provided by the incidence in a group of exceptionally young patients with a consistent and unusual neuropathological profile. The outcome of mouse transmission studies and the future incidence of the disease in the United Kingdom and elsewhere, will be important in judging whether the agent causing bovine spongiform encephalopathy has infected humans.", "title": "Sporadic Creutzfeldt-Jakob disease in the United Kingdom: analysis of epidemiological surveillance data for 1970-96." }, { "docid": "30844602", "text": "PROBLEM/CONDITION Since 1973, CDC has maintained a collaborative surveillance program for collection and periodic reporting of data on the occurrence and causes of foodborne-disease outbreaks (FBDOs) in the United States. REPORTING PERIOD COVERED This summary reviews data from January 1993 through December 1997. DESCRIPTION OF SYSTEM The Foodborne-Disease Outbreak Surveillance System reviews data concerning FBDOs, defined as the occurrence of two or more cases of a similar illness resulting from the ingestion of a common food. State and local public health departments have primary responsibility for identifying and investigating FBDOs. State, local, and territorial health departments use a standard form to report these outbreaks to CDC. \n RESULTS During 1993-1997, a total of 2,751 outbreaks of foodborne disease were reported (489 in 1993, 653 in 1994, 628 in 1995, 477 in 1996, and 504 in 1997). These outbreaks caused a reported 86,058 persons to become ill. Among outbreaks for which the etiology was determined, bacterial pathogens caused the largest percentage of outbreaks (75%) and the largest percentage of cases (86%). Salmonella serotype Enteritidis accounted for the largest number of outbreaks, cases, and deaths; most of these outbreaks were attributed to eating eggs. Chemical agents caused 17% of outbreaks and 1% of cases; viruses, 6% of outbreaks and 8% of cases; and parasites, 2% of outbreaks and 5% of cases. \n INTERPRETATION The annual number of FBDOs reported to CDC did not change substantially during this period or from previous years. During this reporting period, S. Enteritidis continued to be a major cause of illness and death. In addition, multistate outbreaks caused by contaminated produce and outbreaks caused by Escherichia coli O157:H7 remained prominent. ACTIONS TAKEN Current methods to detect FBDOs are improving, and several changes to improve the ease and timeliness of reporting FBDO data are occurring (e.g., a revised form to simplify FBDO reporting by state health departments and electronic reporting methods). State and local health departments continue to investigate and report FBDOs as part of efforts to better understand and define the epidemiology of foodborne disease in the United States. At the regional and national levels, surveillance data provide an indication of the etiologic agents, vehicles of transmission, and contributing factors associated with FBDOs and help direct public health actions to reduce illness and death caused by FBDOs.", "title": "Surveillance for foodborne-disease outbreaks--United States, 1993-1997." }, { "docid": "13899137", "text": "BACKGROUND Many mathematical models have investigated the impact of expanding access to antiretroviral therapy (ART) on new HIV infections. Comparing results and conclusions across models is challenging because models have addressed slightly different questions and have reported different outcome metrics. This study compares the predictions of several mathematical models simulating the same ART intervention programmes to determine the extent to which models agree about the epidemiological impact of expanded ART. \n METHODS AND FINDINGS Twelve independent mathematical models evaluated a set of standardised ART intervention scenarios in South Africa and reported a common set of outputs. Intervention scenarios systematically varied the CD4 count threshold for treatment eligibility, access to treatment, and programme retention. For a scenario in which 80% of HIV-infected individuals start treatment on average 1 y after their CD4 count drops below 350 cells/µl and 85% remain on treatment after 3 y, the models projected that HIV incidence would be 35% to 54% lower 8 y after the introduction of ART, compared to a counterfactual scenario in which there is no ART. More variation existed in the estimated long-term (38 y) reductions in incidence. The impact of optimistic interventions including immediate ART initiation varied widely across models, maintaining substantial uncertainty about the theoretical prospect for elimination of HIV from the population using ART alone over the next four decades. The number of person-years of ART per infection averted over 8 y ranged between 5.8 and 18.7. Considering the actual scale-up of ART in South Africa, seven models estimated that current HIV incidence is 17% to 32% lower than it would have been in the absence of ART. Differences between model assumptions about CD4 decline and HIV transmissibility over the course of infection explained only a modest amount of the variation in model results. \n CONCLUSIONS Mathematical models evaluating the impact of ART vary substantially in structure, complexity, and parameter choices, but all suggest that ART, at high levels of access and with high adherence, has the potential to substantially reduce new HIV infections. There was broad agreement regarding the short-term epidemiologic impact of ambitious treatment scale-up, but more variation in longer term projections and in the efficiency with which treatment can reduce new infections. Differences between model predictions could not be explained by differences in model structure or parameterization that were hypothesized to affect intervention impact.", "title": "HIV Treatment as Prevention: Systematic Comparison of Mathematical Models of the Potential Impact of Antiretroviral Therapy on HIV Incidence in South Africa" }, { "docid": "253672", "text": "OBJECTIVE To determine whether the novel avian influenza H7N9 virus can transmit from person to person and its efficiency. \n DESIGN Epidemiological investigations conducted after a family cluster of two patients with avian H7N9 in March 2013. \n SETTING Wuxi, Eastern China. \n PARTICIPANTS Two patients, their close contacts, and relevant environments. Samples from the patients and environments were collected and tested by real time reverse transcriptase-polymerase chain reaction (rRT-PCR), viral culture, and haemagglutination inhibition assay. Any contacts who became ill had samples tested for avian H7N9 by rRT-PCR. Paired serum samples were obtained from contacts for serological testing by haemagglutination inhibition assays. \n MAIN OUTCOMES MEASURES Clinical data, history of exposure before the onset of illnesses, and results of laboratory testing of pathogens and further analysis of sequences and phylogenetic tree to isolated strains. \n RESULTS The index patient became ill five to six days after his last exposure to poultry. The second patient, his daughter aged 32, who provided unprotected bedside care in the hospital, had no known exposure to poultry. She developed symptoms six days after her last contact with her father. Two strains were isolated successfully from the two patients. Genome sequence and analyses of phylogenetic trees showed that both viruses were almost genetically identical. Forty three close contacts of both patients were identified. One had mild illness but had negative results for avian H7N9 by rRT-PCR. All 43 close contacts tested negative for haemagglutination inhibition antibodies specific for avian H7N9. \n CONCLUSIONS The infection of the daughter probably resulted from contact with her father (the index patient) during unprotected exposure, suggesting that in this cluster the virus was able to transmit from person to person. The transmissibility was limited and non-sustainable.", "title": "Probable person to person transmission of novel avian influenza A (H7N9) virus in Eastern China, 2013: epidemiological investigation" }, { "docid": "22023404", "text": "CONTEXT Vitamin D deficiency is associated with many adverse health outcomes, yet little is known about the genetic epidemiology of vitamin D or its metabolites. \n OBJECTIVE Our objective was to examine the relationship among three vitamin D-related genes and levels of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)2D] in Hispanics (HAs) and African Americans (AAs). \n DESIGN AND SETTING The cross-sectional Insulin Resistance Atherosclerosis Family Study recruited and examined subjects in: Los Angeles, California (AAs; 513 individuals from 42 families); San Luis Valley (SLV), Colorado (HAs; 513 individuals from 30 families); and San Antonio (SA), Texas (HAs; 504 individuals from 58 families). \n MAIN OUTCOME MEASURES Plasma levels of 25(OH)D and 1,25(OH)2D were measured. \n RESULTS Levels of 25(OH)D were highest in SLV-HAs [18.3 +/- 7.7 ng/ml (45.7 +/- 19.2 nmol/liter)], lower in SA-HAs [14.6 +/- 6.4 ng/ml (36.4 +/- 16.0 nmol/liter)], and lowest in AAs [11.0 +/- 5.4 ng/ml (27.5 +/- 13.5 nmol/liter)]. Levels of 1,25(OH)2D were similar in AAs [43.5 +/- 13.9 pg/ml (113.1 +/- 36.1 pmol/liter)] and SLV-HAs [43.2 +/- 13.3 pg/ml (112.3 +/- 34.6 pmol/liter)], but higher in SA-HAs [48.6 +/- 17.0 pg/ml (126.4 +/- 44.2 pmol/liter)]. After adjusting for gender and age within the site, two single nucleotide polymorphisms (SNPs) in the vitamin D binding protein gene (DBP), rs4588 and rs7041, were associated with 25(OH)D, and one SNP in the DBP, rs4588, was associated with 1,25(OH)2D at all three study centers. \n CONCLUSIONS SNPs in the DBP are associated with levels of 25(OH)D and 1,25(OH)2D in HA and AA participants in the Insulin Resistance Atherosclerosis Family Study.", "title": "Genetic and environmental determinants of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels in Hispanic and African Americans." }, { "docid": "12438901", "text": "BACKGROUND For women with oestrogen receptor (ER)-positive early breast cancer, treatment with tamoxifen for 5 years substantially reduces the breast cancer mortality rate throughout the first 15 years after diagnosis. We aimed to assess the further effects of continuing tamoxifen to 10 years instead of stopping at 5 years. \n METHODS In the worldwide Adjuvant Tamoxifen: Longer Against Shorter (ATLAS) trial, 12,894 women with early breast cancer who had completed 5 years of treatment with tamoxifen were randomly allocated to continue tamoxifen to 10 years or stop at 5 years (open control). Allocation (1:1) was by central computer, using minimisation. After entry (between 1996 and 2005), yearly follow-up forms recorded any recurrence, second cancer, hospital admission, or death. We report effects on breast cancer outcomes among the 6846 women with ER-positive disease, and side-effects among all women (with positive, negative, or unknown ER status). Long-term follow-up still continues. This study is registered, number ISRCTN19652633. \n FINDINGS Among women with ER-positive disease, allocation to continue tamoxifen reduced the risk of breast cancer recurrence (617 recurrences in 3428 women allocated to continue vs 711 in 3418 controls, p=0·002), reduced breast cancer mortality (331 deaths vs 397 deaths, p=0·01), and reduced overall mortality (639 deaths vs 722 deaths, p=0·01). The reductions in adverse breast cancer outcomes appeared to be less extreme before than after year 10 (recurrence rate ratio [RR] 0·90 [95% CI 0·79–1·02] during years 5–9 and 0·75 [0·62–0·90] in later years; breast cancer mortality RR 0·97 [0·79–1·18] during years 5–9 and 0·71 [0·58–0·88] in later years). The cumulative risk of recurrence during years 5–14 was 21·4% for women allocated to continue versus 25·1% for controls; breast cancer mortality during years 5–14 was 12·2% for women allocated to continue versus 15·0% for controls (absolute mortality reduction 2·8%). Treatment allocation seemed to have no effect on breast cancer outcome among 1248 women with ER-negative disease, and an intermediate effect among 4800 women with unknown ER status. Among all 12,894 women, mortality without recurrence from causes other than breast cancer was little affected (691 deaths without recurrence in 6454 women allocated to continue versus 679 deaths in 6440 controls; RR 0·99 [0·89–1·10]; p=0·84). For the incidence (hospitalisation or death) rates of specific diseases, RRs were as follows: pulmonary embolus 1·87 (95% CI 1·13–3·07, p=0·01 [including 0·2% mortality in both treatment groups]), stroke 1·06 (0·83–1·36), ischaemic heart disease 0·76 (0·60–0·95, p=0·02), and endometrial cancer 1·74 (1·30–2·34, p=0·0002). The cumulative risk of endometrial cancer during years 5–14 was 3·1% (mortality 0·4%) for women allocated to continue versus 1·6% (mortality 0·2%) for controls (absolute mortality increase 0·2%). \n INTERPRETATION For women with ER-positive disease, continuing tamoxifen to 10 years rather than stopping at 5 years produces a further reduction in recurrence and mortality, particularly after year 10. These results, taken together with results from previous trials of 5 years of tamoxifen treatment versus none, suggest that 10 years of tamoxifen treatment can approximately halve breast cancer mortality during the second decade after diagnosis. \n FUNDING Cancer Research UK, UK Medical Research Council, AstraZeneca UK, US Army, EU-Biomed.", "title": "Long-term effects of continuing adjuvant tamoxifen to 10 years versus stopping at 5 years after diagnosis of oestrogen receptor-positive breast cancer: ATLAS, a randomised trial" }, { "docid": "25121903", "text": "The number of cancer survivors continues to increase due to the aging and growth of the population and improvements in early detection and treatment. In order for the public health community to better serve these survivors, the American Cancer Society and the National Cancer Institute collaborated to estimate the number of current and future cancer survivors using data from the Surveillance, Epidemiology, and End Results (SEER) program registries. In addition, current treatment patterns for the most common cancer types are described based on information in the National Cancer Data Base and the SEER and SEER-Medicare linked databases; treatment-related side effects are also briefly described. Nearly 14.5 million Americans with a history of cancer were alive on January 1, 2014; by January 1, 2024, that number will increase to nearly 19 million. The 3 most common prevalent cancers among males are prostate cancer (43%), colorectal cancer (9%), and melanoma (8%), and those among females are cancers of the breast (41%), uterine corpus (8%), and colon and rectum (8%). The age distribution of survivors varies substantially by cancer type. For example, the majority of prostate cancer survivors (62%) are aged 70 years or older, whereas less than one-third (32%) of melanoma survivors are in this older age group. It is important for clinicians to understand the unique medical and psychosocial needs of cancer survivors and to proactively assess and manage these issues. There are a growing number of resources that can assist patients, caregivers, and health care providers in navigating the various phases of cancer survivorship.", "title": "Cancer treatment and survivorship statistics, 2014." }, { "docid": "18816720", "text": "BACKGROUND Transmission of dengue viruses (DENV), the leading cause of arboviral disease worldwide, is known to vary through time and space, likely owing to a combination of factors related to the human host, virus, mosquito vector, and environment. An improved understanding of variation in transmission patterns is fundamental to conducting surveillance and implementing disease prevention strategies. To test the hypothesis that DENV transmission is spatially and temporally focal, we compared geographic and temporal characteristics within Thai villages where DENV are and are not being actively transmitted. \n METHODS AND FINDINGS Cluster investigations were conducted within 100 m of homes where febrile index children with (positive clusters) and without (negative clusters) acute dengue lived during two seasons of peak DENV transmission. Data on human infection and mosquito infection/density were examined to precisely (1) define the spatial and temporal dimensions of DENV transmission, (2) correlate these factors with variation in DENV transmission, and (3) determine the burden of inapparent and symptomatic infections. Among 556 village children enrolled as neighbors of 12 dengue-positive and 22 dengue-negative index cases, all 27 DENV infections (4.9% of enrollees) occurred in positive clusters (p < 0.01; attributable risk [AR] = 10.4 per 100; 95% confidence interval 1-19.8 per 100]. In positive clusters, 12.4% of enrollees became infected in a 15-d period and DENV infections were aggregated centrally near homes of index cases. As only 1 of 217 pairs of serologic specimens tested in positive clusters revealed a recent DENV infection that occurred prior to cluster initiation, we attribute the observed DENV transmission subsequent to cluster investigation to recent DENV transmission activity. Of the 1,022 female adult Ae. aegypti collected, all eight (0.8%) dengue-infected mosquitoes came from houses in positive clusters; none from control clusters or schools. Distinguishing features between positive and negative clusters were greater availability of piped water in negative clusters (p < 0.01) and greater number of Ae. aegypti pupae per person in positive clusters (p = 0.04). During primarily DENV-4 transmission seasons, the ratio of inapparent to symptomatic infections was nearly 1:1 among child enrollees. Study limitations included inability to sample all children and mosquitoes within each cluster and our reliance on serologic rather than virologic evidence of interval infections in enrollees given restrictions on the frequency of blood collections in children. \n CONCLUSIONS Our data reveal the remarkably focal nature of DENV transmission within a hyperendemic rural area of Thailand. These data suggest that active school-based dengue case detection prompting local spraying could contain recent virus introductions and reduce the longitudinal risk of virus spread within rural areas. Our results should prompt future cluster studies to explore how host immune and behavioral aspects may impact DENV transmission and prevention strategies. Cluster methodology could serve as a useful research tool for investigation of other temporally and spatially clustered infectious diseases.", "title": "Spatial and Temporal Clustering of Dengue Virus Transmission in Thai Villages" }, { "docid": "34760396", "text": "The fly Musca sorbens Wiedemann (Diptera: Muscidae) apparently transmits Chlamydia trachomatis, causing human trachoma. The literature indicates that M. sorbens breeds predominantly in isolated human faeces on the soil surface, but not in covered pit latrines. We sought to identify breeding media of M. sorbens in a rural Gambian village endemic for trachoma. Test breeding media were presented for oviposition on soil-filled buckets and monitored for adult emergence. Musca sorbens emerged from human (6/9 trials), calf (3/9), cow (3/9), dog (2/9) and goat (1/9) faeces, but not from horse faeces, composting kitchen scraps or a soil control (0/9 of each). After adjusting for mass of medium, the greatest number of flies emerged from human faeces (1426 flies/kg). Median time for emergence was 9 (inter quartile range = 8-9.75) days post-oviposition. Of all flies emerging from faeces 81% were M. sorbens. Male and female flies emerging from human faeces were significantly larger than those from other media, suggesting that they would be more fecund and live longer than smaller flies from other sources. Female flies caught from children's eyes were of a similar size to those from human faeces, but significantly larger than those from other media. We consider that human faeces are the best larval medium for M. sorbens, although some breeding also occurs in animal faeces. Removal of human faeces from the environment, through the provision of basic sanitation, is likely to greatly reduce fly density, eye contact and hence trachoma transmission, but if faeces of other animals are present M. sorbens will persist.", "title": "Human and other faeces as breeding media of the trachoma vector Musca sorbens." }, { "docid": "25499612", "text": "Despite its key role in determining the stability and intensity of malaria transmission, the infectiousness of human populations to mosquitoes has rarely been estimated. Field-based analyses of malaria transmission have frequently relied on the prevalence of asexual parasites or gametocytes as proxies for infectiousness. We now summarize empirical data on human infectiousness from Africa and Papua New Guinea. Over a wide range of transmission intensities there is little relationship between the infectiousness of human populations to vector mosquitoes and mosquito-to-human transmission intensity. We compare these data with the predictions of a stochastic simulation model of Plasmodium falciparum epidemiology. This model predicted little variation in the infectiousness of the human population for entomologic inoculation rates (EIRs) greater than approximately 10 infectious bites per year, demonstrating that the lack of relationship between the EIR and the infectious reservoir can be explained without invoking any effects of acquired transmission-blocking immunity. The near absence of field data from areas with an EIR < 10 per year precluded validation of the model predictions for low EIR values. These results suggest that interventions reducing mosquito-to-human transmission will have little or no effect on human infectiousness at the levels of transmission found in most rural areas of sub-Saharan Africa. Unless very large reductions in transmission can be achieved, measures to prevent mosquito-to-human transmission need to be complemented with interventions that reduce the density or infectiousness of blood stage parasites.", "title": "Infectiousness of malaria-endemic human populations to vectors." } ]

[ { "docid": "4709641", "text": "Efforts to develop drugs for Alzheimer's disease (AD) have shown promise in animal studies, only to fail in human trials, suggesting a pressing need to study AD in human model systems. Using human neurons derived from induced pluripotent stem cells that expressed apolipoprotein E4 (ApoE4), a variant of the APOE gene product and the major genetic risk factor for AD, we demonstrated that ApoE4-expressing neurons had higher levels of tau phosphorylation, unrelated to their increased production of amyloid-β (Aβ) peptides, and that they displayed GABAergic neuron degeneration. ApoE4 increased Aβ production in human, but not in mouse, neurons. Converting ApoE4 to ApoE3 by gene editing rescued these phenotypes, indicating the specific effects of ApoE4. Neurons that lacked APOE behaved similarly to those expressing ApoE3, and the introduction of ApoE4 expression recapitulated the pathological phenotypes, suggesting a gain of toxic effects from ApoE4. Treatment of ApoE4-expressing neurons with a small-molecule structure corrector ameliorated the detrimental effects, thus showing that correcting the pathogenic conformation of ApoE4 is a viable therapeutic approach for ApoE4-related AD.", "title": "Gain of toxic Apolipoprotein E4 effects in Human iPSC-Derived Neurons Is Ameliorated by a Small-Molecule Structure Corrector" } ]

[ { "docid": "15347087", "text": "The amyloid cascade hypothesis posits that deposition of the amyloid β (Aβ) peptide in the brain is a key event in the initiation of Alzheimer's disease (AD). Nonetheless, it now seems increasingly unlikely that amyloid toxicity is the cause of sporadic AD, which leads to cognitive decline. Here, using accelerated-senescence nontransgenic OXYS rats, we confirmed that aggregation of Aβ is a later event in AD-like pathology. We showed that an age-dependent increase in the levels of Aβ₁₋₄₂ and extracellular Aβ deposits in the brain of OXYS rats occur later than do synaptic losses, neuronal cell death, mitochondrial structural abnormalities, and hyperphosphorylation of the tau protein. We identified the variants of the genes that are strongly associated with the risk of either late-onset or early-onset AD, including App, Apoe4, Bace1, Psen1, Psen2, and Picalm. We found that in OXYS rats nonsynonymous SNPs were located only in the genes Casp3 and Sorl1. Thus, we present proof that OXYS rats may be a model of sporadic AD. It is possible that multiple age-associated pathological processes may precede the toxic amyloid accumulation, which in turn triggers the final stage of the sporadic form of AD and becomes a hallmark event of the disease.", "title": "Amyloid accumulation is a late event in sporadic Alzheimer's disease-like pathology in nontransgenic rats" }, { "docid": "47018050", "text": "Here, we report that genome editing by CRISPR–Cas9 induces a p53-mediated DNA damage response and cell cycle arrest in immortalized human retinal pigment epithelial cells, leading to a selection against cells with a functional p53 pathway. Inhibition of p53 prevents the damage response and increases the rate of homologous recombination from a donor template. These results suggest that p53 inhibition may improve the efficiency of genome editing of untransformed cells and that p53 function should be monitored when developing cell-based therapies utilizing CRISPR–Cas9. CRISPR–Cas9-induced DNA damage triggers p53 to limit the efficiency of gene editing in immortalized human retinal pigment epithelial cells.", "title": "CRISPR–Cas9 genome editing induces a p53-mediated DNA damage response" }, { "docid": "13717103", "text": "INTRODUCTION Mutations in the FUS gene have been shown to be a rare cause of amyotrophic lateral sclerosis (ALS-FUS) and whilst well documented clinically and genetically there have been relatively few neuropathological studies. Recent work suggested a possible correlation between pathological features such as frequency of basophilic inclusions in neurons and rate of clinical decline, other studies have revealed a discrepancy between the upper motor neuron features detected clinically and the associated pathology. The purpose of this study was to describe the pathological features associated with more recently discovered FUS mutations and reinvestigate those with well recognised mutations in an attempt to correlate the pathology with mutation and/or clinical phenotype. The brains and spinal cords of seven cases of ALS-FUS were examined neuropathologically, including cases with the newly described p. K510E mutation and a case with both a known p. P525L mutation in the FUS gene and a truncating p. Y374X mutation in the TARDBP gene. \n RESULTS The neuropathology in all cases revealed basophilic and FUS inclusions in the cord. The density and type of inclusions varied markedly between cases, but did not allow a clear correlation with clinical progression. Only one case showed significant motor cortical pathology despite the upper motor neuron clinical features being evident in 4 patients. The case with both a FUS and TARDBP mutation revealed FUS positive inclusions but no TDP-43 pathology. Instead there were unusual p62 positive, FUS negative neuronal and glial inclusions as well as dot-like neurites. \n CONCLUSIONS The study confirms cases of ALS-FUS to be mainly a lower motor neuron disease and to have pathology that does not appear to neatly correlate with clinical features or genetics. Furthermore, the case with both a FUS and TARDBP mutation reveals an intriguing pathological profile which at least in part involves a very unusual staining pattern for the ubiquitin-binding protein p62.", "title": "ALS-FUS pathology revisited: singleton FUS mutations and an unusual case with both a FUS and TARDBP mutation" }, { "docid": "5953485", "text": "Adenosine deaminases acting on RNA (ADARs) are involved in RNA editing that converts adenosine residues to inosine specifically in double-stranded RNAs. In this study, we investigated the interaction of the RNA editing mechanism with the RNA interference (RNAi) machinery and found that ADAR1 forms a complex with Dicer through direct protein-protein interaction. Most importantly, ADAR1 increases the maximum rate (Vmax) of pre-microRNA (miRNA) cleavage by Dicer and facilitates loading of miRNA onto RNA-induced silencing complexes, identifying a new role of ADAR1 in miRNA processing and RNAi mechanisms. ADAR1 differentiates its functions in RNA editing and RNAi by the formation of either ADAR1/ADAR1 homodimer or Dicer/ADAR1 heterodimer complexes, respectively. As expected, the expression of miRNAs is globally inhibited in ADAR1(-/-) mouse embryos, which, in turn, alters the expression of their target genes and might contribute to their embryonic lethal phenotype.", "title": "ADAR1 Forms a Complex with Dicer to Promote MicroRNA Processing and RNA-Induced Gene Silencing" }, { "docid": "4405194", "text": "Somatic cell nuclear transfer, cell fusion, or expression of lineage-specific factors have been shown to induce cell-fate changes in diverse somatic cell types. We recently observed that forced expression of a combination of three transcription factors, Brn2 (also known as Pou3f2), Ascl1 and Myt1l, can efficiently convert mouse fibroblasts into functional induced neuronal (iN) cells. Here we show that the same three factors can generate functional neurons from human pluripotent stem cells as early as 6 days after transgene activation. When combined with the basic helix-loop-helix transcription factor NeuroD1, these factors could also convert fetal and postnatal human fibroblasts into iN cells showing typical neuronal morphologies and expressing multiple neuronal markers, even after downregulation of the exogenous transcription factors. Importantly, the vast majority of human iN cells were able to generate action potentials and many matured to receive synaptic contacts when co-cultured with primary mouse cortical neurons. Our data demonstrate that non-neural human somatic cells, as well as pluripotent stem cells, can be converted directly into neurons by lineage-determining transcription factors. These methods may facilitate robust generation of patient-specific human neurons for in vitro disease modelling or future applications in regenerative medicine.", "title": "Induction of human neuronal cells by defined transcription factors" }, { "docid": "4303075", "text": "Cellular differentiation and lineage commitment are considered to be robust and irreversible processes during development. Recent work has shown that mouse and human fibroblasts can be reprogrammed to a pluripotent state with a combination of four transcription factors. This raised the question of whether transcription factors could directly induce other defined somatic cell fates, and not only an undifferentiated state. We hypothesized that combinatorial expression of neural-lineage-specific transcription factors could directly convert fibroblasts into neurons. Starting from a pool of nineteen candidate genes, we identified a combination of only three factors, Ascl1, Brn2 (also called Pou3f2) and Myt1l, that suffice to rapidly and efficiently convert mouse embryonic and postnatal fibroblasts into functional neurons in vitro. These induced neuronal (iN) cells express multiple neuron-specific proteins, generate action potentials and form functional synapses. Generation of iN cells from non-neural lineages could have important implications for studies of neural development, neurological disease modelling and regenerative medicine.", "title": "Direct conversion of fibroblasts to functional neurons by defined factors" }, { "docid": "461550", "text": "Functional elucidation of causal genetic variants and elements requires precise genome editing technologies. The type II prokaryotic CRISPR (clustered regularly interspaced short palindromic repeats)/Cas adaptive immune system has been shown to facilitate RNA-guided site-specific DNA cleavage. We engineered two different type II CRISPR/Cas systems and demonstrate that Cas9 nucleases can be directed by short RNAs to induce precise cleavage at endogenous genomic loci in human and mouse cells. Cas9 can also be converted into a nicking enzyme to facilitate homology-directed repair with minimal mutagenic activity. Lastly, multiple guide sequences can be encoded into a single CRISPR array to enable simultaneous editing of several sites within the mammalian genome, demonstrating easy programmability and wide applicability of the RNA-guided nuclease technology.", "title": "Multiplex genome engineering using CRISPR/Cas systems." }, { "docid": "4679264", "text": "The role of DNA cytosine methylation, an epigenetic regulator of chromatin structure and function, during normal and pathological brain development and aging remains unclear. Here, we examined by MethyLight PCR the DNA methylation status at 50 loci, encompassing primarily 5′ CpG islands of genes related to CNS growth and development, in temporal neocortex of 125 subjects ranging in age from 17 weeks of gestation to 104 years old. Two psychiatric disease cohorts—defined by chronic neurodegeneration (Alzheimer's) or lack thereof (schizophrenia)—were included. A robust and progressive rise in DNA methylation levels across the lifespan was observed for 8/50 loci (GABRA2, GAD1, HOXA1, NEUROD1, NEUROD2, PGR, STK11, SYK) typically in conjunction with declining levels of the corresponding mRNAs. Another 16 loci were defined by a sharp rise in DNA methylation levels within the first few months or years after birth. Disease-associated changes were limited to 2/50 loci in the Alzheimer's cohort, which appeared to reflect an acceleration of the age-related change in normal brain. Additionally, methylation studies on sorted nuclei provided evidence for bidirectional methylation events in cortical neurons during the transition from childhood to advanced age, as reflected by significant increases at 3, and a decrease at 1 of 10 loci. Furthermore, the DNMT3a de novo DNA methyl-transferase was expressed across all ages, including a subset of neurons residing in layers III and V of the mature cortex. Therefore, DNA methylation is dynamically regulated in the human cerebral cortex throughout the lifespan, involves differentiated neurons, and affects a substantial portion of genes predominantly by an age-related increase.", "title": "DNA Methylation in the Human Cerebral Cortex Is Dynamically Regulated throughout the Life Span and Involves Differentiated Neurons" }, { "docid": "4459491", "text": "Alzheimer’s disease is the most common form of dementia, characterized by two pathological hallmarks: amyloid-β plaques and neurofibrillary tangles. The amyloid hypothesis of Alzheimer’s disease posits that the excessive accumulation of amyloid-β peptide leads to neurofibrillary tangles composed of aggregated hyperphosphorylated tau. However, to date, no single disease model has serially linked these two pathological events using human neuronal cells. Mouse models with familial Alzheimer’s disease (FAD) mutations exhibit amyloid-β-induced synaptic and memory deficits but they do not fully recapitulate other key pathological events of Alzheimer’s disease, including distinct neurofibrillary tangle pathology. Human neurons derived from Alzheimer’s disease patients have shown elevated levels of toxic amyloid-β species and phosphorylated tau but did not demonstrate amyloid-β plaques or neurofibrillary tangles. Here we report that FAD mutations in β-amyloid precursor protein and presenilin 1 are able to induce robust extracellular deposition of amyloid-β, including amyloid-β plaques, in a human neural stem-cell-derived three-dimensional (3D) culture system. More importantly, the 3D-differentiated neuronal cells expressing FAD mutations exhibited high levels of detergent-resistant, silver-positive aggregates of phosphorylated tau in the soma and neurites, as well as filamentous tau, as detected by immunoelectron microscopy. Inhibition of amyloid-β generation with β- or γ-secretase inhibitors not only decreased amyloid-β pathology, but also attenuated tauopathy. We also found that glycogen synthase kinase 3 (GSK3) regulated amyloid-β-mediated tau phosphorylation. We have successfully recapitulated amyloid-β and tau pathology in a single 3D human neural cell culture system. Our unique strategy for recapitulating Alzheimer’s disease pathology in a 3D neural cell culture model should also serve to facilitate the development of more precise human neural cell models of other neurodegenerative disorders.", "title": "A three-dimensional human neural cell culture model of Alzheimer’s disease" }, { "docid": "6397191", "text": "Endothelin-1 (ET-1) is the predominant endothelin isopeptide generated by the vascular wall and therefore appears to be the most important peptide involved in regulation of cardiovascular events. Many pathologic conditions are associated with elevations of ET-1 in the blood vessel wall. Because these conditions are often cytokine driven, we examined the effects of a mixture of cytokines on ET-1 production in human vascular smooth muscle cells (VSMCs) derived from internal mammary artery and saphenous vein (SV). Incubation of IMA and SV VSMCs with tumor necrosis factor-alpha (10 ng/ml) and interferon-gamma (1000 U/ml) in combination for up to 48 h markedly elevated the expression of mRNA for prepro-ET-1 and the release of ET-1 into the culture medium. This cytokine-stimulated release of ET-1 was inhibited by a series of dual endothelin-converting enzyme (ECE)/neutral endopeptidase inhibitors, phosphoramidon, CGS 26303, and CGS 26393, with an accompanying increase in big ET-1 release but with no effect on expression of mRNA for prepro-ET-1. These same compounds were 10 times more potent at inhibiting the conversion of exogenously applied big ET-1 to ET-1. ECE-1b/c mRNA is present in SV VSMCs, however no ECE-1a is present in these cells. Thus VSMCs most probably contain, like endothelial cells, an intracellular ECE responsible for the endogenous synthesis of ET-1. Under the influence of pro-inflammatory mediators the vascular smooth muscle can therefore become an important site of ET-1 production, as has already been established for the dilator mediators nitric oxide, prostaglandin I2, and prostaglandin E2.", "title": "Endothelin-1 is induced by cytokines in human vascular smooth muscle cells: evidence for intracellular endothelin-converting enzyme." }, { "docid": "13293033", "text": "Down syndrome (DS) is the most frequent cause of human congenital mental retardation. Cognitive deficits in DS result from perturbations of normal cellular processes both during development and in adult tissues, but the mechanisms underlying DS etiology remain poorly understood. To assess the ability of induced pluripotent stem cells (iPSCs) to model DS phenotypes, as a prototypical complex human disease, we generated bona fide DS and wild-type (WT) nonviral iPSCs by episomal reprogramming. DS iPSCs selectively overexpressed chromosome 21 genes, consistent with gene dosage, which was associated with deregulation of thousands of genes throughout the genome. DS and WT iPSCs were neurally converted at >95% efficiency and had remarkably similar lineage potency, differentiation kinetics, proliferation, and axon extension at early time points. However, at later time points DS cultures showed a twofold bias toward glial lineages. Moreover, DS neural cultures were up to two times more sensitive to oxidative stress-induced apoptosis, and this could be prevented by the antioxidant N-acetylcysteine. Our results reveal a striking complexity in the genetic alterations caused by trisomy 21 that are likely to underlie DS developmental phenotypes, and indicate a central role for defective early glial development in establishing developmental defects in DS brains. Furthermore, oxidative stress sensitivity is likely to contribute to the accelerated neurodegeneration seen in DS, and we provide proof of concept for screening corrective therapeutics using DS iPSCs and their derivatives. Nonviral DS iPSCs can therefore model features of complex human disease in vitro and provide a renewable and ethically unencumbered discovery platform.", "title": "Integration-free induced pluripotent stem cells model genetic and neural developmental features of down syndrome etiology." }, { "docid": "4347374", "text": "Viral replication usually requires that innate intracellular lines of defence be overcome, a task usually accomplished by specialized viral gene products. The virion infectivity factor (Vif) protein of human immunodeficiency virus (HIV) is required during the late stages of viral production to counter the antiviral activity of APOBEC3G (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G; also known as CEM15), a protein expressed notably in human T lymphocytes. When produced in the presence of APOBEC3G, vif-defective virus is non-infectious. APOBEC3G is closely related to APOBEC1, the central component of an RNA-editing complex that deaminates a cytosine residue in apoB messenger RNA. APOBEC family members also have potent DNA mutator activity through dC deamination; however, whether the editing potential of APOBEC3G has any relevance to HIV inhibition is unknown. Here, we demonstrate that it does, as APOBEC3G exerts its antiviral effect during reverse transcription to trigger G-to-A hypermutation in the nascent retroviral DNA. We also find that APOBEC3G can act on a broad range of retroviruses in addition to HIV, suggesting that hypermutation by editing is a general innate defence mechanism against this important group of pathogens.", "title": "Broad antiretroviral defence by human APOBEC3G through lethal editing of nascent reverse transcripts" }, { "docid": "9217800", "text": "The fatal adult motor neuron disease amyotrophic lateral sclerosis (ALS) shares some clinical and pathological overlap with frontotemporal dementia (FTD), an early-onset neurodegenerative disorder. The RNA/DNA-binding proteins fused in sarcoma (FUS; also known as TLS) and TAR DNA binding protein-43 (TDP-43) have recently been shown to be genetically and pathologically associated with familial forms of ALS and FTD. It is currently unknown whether perturbation of these proteins results in disease through mechanisms that are independent of normal protein function or via the pathophysiological disruption of molecular processes in which they are both critical. Here, we report that Drosophila mutants in which the homolog of FUS is disrupted exhibit decreased adult viability, diminished locomotor speed, and reduced life span compared with controls. These phenotypes were fully rescued by wild-type human FUS, but not ALS-associated mutant FUS proteins. A mutant of the Drosophila homolog of TDP-43 had similar, but more severe, deficits. Through cross-rescue analysis, we demonstrated that FUS acted together with and downstream of TDP-43 in a common genetic pathway in neurons. Furthermore, we found that these proteins associated with each other in an RNA-dependent complex. Our results establish that FUS and TDP-43 function together in vivo and suggest that molecular pathways requiring the combined activities of both of these proteins may be disrupted in ALS and FTD.", "title": "The ALS-associated proteins FUS and TDP-43 function together to affect Drosophila locomotion and life span." }, { "docid": "13296399", "text": "Reliable genome editing via Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 may provide a means to correct inherited diseases in patients. As proof of principle, we show that CRISPR/Cas9 can be used in vivo to selectively ablate the rhodopsin gene carrying the dominant S334ter mutation (Rho(S334)) in rats that model severe autosomal dominant retinitis pigmentosa. A single subretinal injection of guide RNA/Cas9 plasmid in combination with electroporation generated allele-specific disruption of Rho(S334), which prevented retinal degeneration and improved visual function.", "title": "In Vivo CRISPR/Cas9 Gene Editing Corrects Retinal Dystrophy in the S334ter-3 Rat Model of Autosomal Dominant Retinitis Pigmentosa" }, { "docid": "17231273", "text": "Energy deficiency and dysfunction of the Na+, K+-ATPase are common consequences of many pathological insults. The nature and mechanism of cell injury induced by impaired Na+, K+-ATPase, however, are not well defined. We used cultured cortical neurons to examine the hypothesis that blocking the Na+, K+-ATPase induces apoptosis by depleting cellular K+ and, concurrently, induces necrotic injury in the same cells by increasing intracellular Ca2+ and Na+. The Na+, K+-ATPase inhibitor ouabain induced concentration-dependent neuronal death. Ouabain triggered transient neuronal cell swelling followed by cell shrinkage, accompanied by intracellular Ca2+ and Na+ increase, K+ decrease, cytochrome c release, caspase-3 activation, and DNA laddering. Electron microscopy revealed the coexistence of ultrastructural features of both apoptosis and necrosis in individual cells. The caspase inhibitor Z-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD-FMK) blocked >50% of ouabain-induced neuronal death. Potassium channel blockers or high K+ medium, but not Ca2+ channel blockade, prevented cytochrome c release, caspase activation, and DNA damage. Blocking of K+, Ca2+, or Na+ channels or high K+ medium each attenuated the ouabain-induced cell death; combined inhibition of K+ channels and Ca2+ or Na+ channels resulted in additional protection. Moreover, coapplication of Z-VAD-FMK and nifedipine produced virtually complete neuroprotection. These results suggest that the neuronal death associated with Na+, K+-pump failure consists of concurrent apoptotic and necrotic components, mediated by intracellular depletion of K+ and accumulation of Ca2+ and Na+, respectively. The ouabain-induced hybrid death may represent a distinct form of cell death related to the brain injury of inadequate energy supply and disrupted ion homeostasis.", "title": "Ionic mechanism of ouabain-induced concurrent apoptosis and necrosis in individual cultured cortical neurons" }, { "docid": "7029990", "text": "One type of RNA editing involves the conversion of adenosine residues into inosine in double-stranded RNA through the action of adenosine deaminases acting on RNA (ADAR). A-to-I RNA editing of the coding sequence could result in synthesis of proteins not directly encoded in the genome. ADAR edits also non-coding sequences of target RNAs, such as introns and 3'-untranslated regions, which may affect splicing, translation, and mRNA stability. Three mammalian ADAR gene family members (ADAR1-3) have been identified. Here we investigated phenotypes of mice homozygous for ADAR1 null mutation. Although live ADAR1-/- embryos with normal gross appearance could be recovered up to E11.5, widespread apoptosis was detected in many tissues. Fibroblasts derived from ADAR1-/- embryos were also prone to apoptosis induced by serum deprivation. Our results demonstrate an essential requirement for ADAR1 in embryogenesis and suggest that it functions to promote survival of numerous tissues by editing one or more double-stranded RNAs required for protection against stress-induced apoptosis.", "title": "Stress-induced apoptosis associated with null mutation of ADAR1 RNA editing deaminase gene." }, { "docid": "4462919", "text": "The RNA-guided endonuclease Cas9 has emerged as a versatile genome-editing platform. However, the size of the commonly used Cas9 from Streptococcus pyogenes (SpCas9) limits its utility for basic research and therapeutic applications that use the highly versatile adeno-associated virus (AAV) delivery vehicle. Here, we characterize six smaller Cas9 orthologues and show that Cas9 from Staphylococcus aureus (SaCas9) can edit the genome with efficiencies similar to those of SpCas9, while being more than 1 kilobase shorter. We packaged SaCas9 and its single guide RNA expression cassette into a single AAV vector and targeted the cholesterol regulatory gene Pcsk9 in the mouse liver. Within one week of injection, we observed >40% gene modification, accompanied by significant reductions in serum Pcsk9 and total cholesterol levels. We further assess the genome-wide targeting specificity of SaCas9 and SpCas9 using BLESS, and demonstrate that SaCas9-mediated in vivo genome editing has the potential to be efficient and specific.", "title": "In vivo genome editing using Staphylococcus aureus Cas9" }, { "docid": "6776834", "text": "Dominant optic atrophy (DOA) is a rare progressive and irreversible blinding disease which is one of the most frequent forms of hereditary optic neuropathy. DOA is mainly caused by dominant mutation in the OPA1 gene encoding a large mitochondrial GTPase with crucial roles in membrane dynamics and cell survival. Hereditary optic neuropathies are commonly characterized by the degeneration of retinal ganglion cells, leading to the optic nerve atrophy and the progressive loss of visual acuity. Up to now, despite increasing advances in the understanding of the pathological mechanisms, DOA remains intractable. Here, we tested the efficiency of gene therapy on a genetically-modified mouse model reproducing DOA vision loss. We performed intravitreal injections of an Adeno-Associated Virus carrying the human OPA1 cDNA under the control of the cytomegalovirus promotor. Our results provide the first evidence that gene therapy is efficient on a mouse model of DOA as the wild-type OPA1 expression is able to alleviate the OPA1-induced retinal ganglion cell degeneration, the hallmark of the disease. These results displayed encouraging effects of gene therapy for Dominant Optic Atrophy, fostering future investigations aiming at clinical trials in patients.", "title": "OPA1 gene therapy prevents retinal ganglion cell loss in a Dominant Optic Atrophy mouse model" }, { "docid": "29107180", "text": "The structure of the human gene encoding the double-stranded RNA (dsRNA) adenosine deaminase (DRADA) was characterized. This nuclear localized enzyme is involved in the RNA editing required for the expression of certain subtypes of glutamate-gated ion channel subunits. The DRADA gene span 30 kb pairs and harbors 15 exons. The transcription of the DRADA gene driven by the putative promoter region, which contains no typical TATA or CCAAT box-like sequences, is initiated at multiple sites, 164 to 216 nucleotides upstream of the translation initiation codon. The three dsRNA binding motifs (DRBM), 70 amino acid residues long, are each encoded by two exons plus an intervening sequence that interrupts the motif at the identical amino acid position. This finding is consistent with the notion that the dsRNA binding domains may be composed of two separate functional subdomains. Fluorescent in situ hybridization localized the DRADA gene on the long arm chromosome 1, region q21. The gene structure and sequence information reported in this study will facilitate the investigation of involvement of DRADA in hereditary diseases that may be the result of malfunction of glutamate-gated ion channels.", "title": "Genomic organization and chromosomal location of the human dsRNA adenosine deaminase gene: the enzyme for glutamate-activated ion channel RNA editing." } ]

[ { "docid": "4709641", "text": "Efforts to develop drugs for Alzheimer's disease (AD) have shown promise in animal studies, only to fail in human trials, suggesting a pressing need to study AD in human model systems. Using human neurons derived from induced pluripotent stem cells that expressed apolipoprotein E4 (ApoE4), a variant of the APOE gene product and the major genetic risk factor for AD, we demonstrated that ApoE4-expressing neurons had higher levels of tau phosphorylation, unrelated to their increased production of amyloid-β (Aβ) peptides, and that they displayed GABAergic neuron degeneration. ApoE4 increased Aβ production in human, but not in mouse, neurons. Converting ApoE4 to ApoE3 by gene editing rescued these phenotypes, indicating the specific effects of ApoE4. Neurons that lacked APOE behaved similarly to those expressing ApoE3, and the introduction of ApoE4 expression recapitulated the pathological phenotypes, suggesting a gain of toxic effects from ApoE4. Treatment of ApoE4-expressing neurons with a small-molecule structure corrector ameliorated the detrimental effects, thus showing that correcting the pathogenic conformation of ApoE4 is a viable therapeutic approach for ApoE4-related AD.", "title": "Gain of toxic Apolipoprotein E4 effects in Human iPSC-Derived Neurons Is Ameliorated by a Small-Molecule Structure Corrector" } ]

[ { "docid": "15347087", "text": "The amyloid cascade hypothesis posits that deposition of the amyloid β (Aβ) peptide in the brain is a key event in the initiation of Alzheimer's disease (AD). Nonetheless, it now seems increasingly unlikely that amyloid toxicity is the cause of sporadic AD, which leads to cognitive decline. Here, using accelerated-senescence nontransgenic OXYS rats, we confirmed that aggregation of Aβ is a later event in AD-like pathology. We showed that an age-dependent increase in the levels of Aβ₁₋₄₂ and extracellular Aβ deposits in the brain of OXYS rats occur later than do synaptic losses, neuronal cell death, mitochondrial structural abnormalities, and hyperphosphorylation of the tau protein. We identified the variants of the genes that are strongly associated with the risk of either late-onset or early-onset AD, including App, Apoe4, Bace1, Psen1, Psen2, and Picalm. We found that in OXYS rats nonsynonymous SNPs were located only in the genes Casp3 and Sorl1. Thus, we present proof that OXYS rats may be a model of sporadic AD. It is possible that multiple age-associated pathological processes may precede the toxic amyloid accumulation, which in turn triggers the final stage of the sporadic form of AD and becomes a hallmark event of the disease.", "title": "Amyloid accumulation is a late event in sporadic Alzheimer's disease-like pathology in nontransgenic rats" }, { "docid": "13717103", "text": "INTRODUCTION Mutations in the FUS gene have been shown to be a rare cause of amyotrophic lateral sclerosis (ALS-FUS) and whilst well documented clinically and genetically there have been relatively few neuropathological studies. Recent work suggested a possible correlation between pathological features such as frequency of basophilic inclusions in neurons and rate of clinical decline, other studies have revealed a discrepancy between the upper motor neuron features detected clinically and the associated pathology. The purpose of this study was to describe the pathological features associated with more recently discovered FUS mutations and reinvestigate those with well recognised mutations in an attempt to correlate the pathology with mutation and/or clinical phenotype. The brains and spinal cords of seven cases of ALS-FUS were examined neuropathologically, including cases with the newly described p. K510E mutation and a case with both a known p. P525L mutation in the FUS gene and a truncating p. Y374X mutation in the TARDBP gene. \n RESULTS The neuropathology in all cases revealed basophilic and FUS inclusions in the cord. The density and type of inclusions varied markedly between cases, but did not allow a clear correlation with clinical progression. Only one case showed significant motor cortical pathology despite the upper motor neuron clinical features being evident in 4 patients. The case with both a FUS and TARDBP mutation revealed FUS positive inclusions but no TDP-43 pathology. Instead there were unusual p62 positive, FUS negative neuronal and glial inclusions as well as dot-like neurites. \n CONCLUSIONS The study confirms cases of ALS-FUS to be mainly a lower motor neuron disease and to have pathology that does not appear to neatly correlate with clinical features or genetics. Furthermore, the case with both a FUS and TARDBP mutation reveals an intriguing pathological profile which at least in part involves a very unusual staining pattern for the ubiquitin-binding protein p62.", "title": "ALS-FUS pathology revisited: singleton FUS mutations and an unusual case with both a FUS and TARDBP mutation" }, { "docid": "5953485", "text": "Adenosine deaminases acting on RNA (ADARs) are involved in RNA editing that converts adenosine residues to inosine specifically in double-stranded RNAs. In this study, we investigated the interaction of the RNA editing mechanism with the RNA interference (RNAi) machinery and found that ADAR1 forms a complex with Dicer through direct protein-protein interaction. Most importantly, ADAR1 increases the maximum rate (Vmax) of pre-microRNA (miRNA) cleavage by Dicer and facilitates loading of miRNA onto RNA-induced silencing complexes, identifying a new role of ADAR1 in miRNA processing and RNAi mechanisms. ADAR1 differentiates its functions in RNA editing and RNAi by the formation of either ADAR1/ADAR1 homodimer or Dicer/ADAR1 heterodimer complexes, respectively. As expected, the expression of miRNAs is globally inhibited in ADAR1(-/-) mouse embryos, which, in turn, alters the expression of their target genes and might contribute to their embryonic lethal phenotype.", "title": "ADAR1 Forms a Complex with Dicer to Promote MicroRNA Processing and RNA-Induced Gene Silencing" }, { "docid": "4405194", "text": "Somatic cell nuclear transfer, cell fusion, or expression of lineage-specific factors have been shown to induce cell-fate changes in diverse somatic cell types. We recently observed that forced expression of a combination of three transcription factors, Brn2 (also known as Pou3f2), Ascl1 and Myt1l, can efficiently convert mouse fibroblasts into functional induced neuronal (iN) cells. Here we show that the same three factors can generate functional neurons from human pluripotent stem cells as early as 6 days after transgene activation. When combined with the basic helix-loop-helix transcription factor NeuroD1, these factors could also convert fetal and postnatal human fibroblasts into iN cells showing typical neuronal morphologies and expressing multiple neuronal markers, even after downregulation of the exogenous transcription factors. Importantly, the vast majority of human iN cells were able to generate action potentials and many matured to receive synaptic contacts when co-cultured with primary mouse cortical neurons. Our data demonstrate that non-neural human somatic cells, as well as pluripotent stem cells, can be converted directly into neurons by lineage-determining transcription factors. These methods may facilitate robust generation of patient-specific human neurons for in vitro disease modelling or future applications in regenerative medicine.", "title": "Induction of human neuronal cells by defined transcription factors" }, { "docid": "4303075", "text": "Cellular differentiation and lineage commitment are considered to be robust and irreversible processes during development. Recent work has shown that mouse and human fibroblasts can be reprogrammed to a pluripotent state with a combination of four transcription factors. This raised the question of whether transcription factors could directly induce other defined somatic cell fates, and not only an undifferentiated state. We hypothesized that combinatorial expression of neural-lineage-specific transcription factors could directly convert fibroblasts into neurons. Starting from a pool of nineteen candidate genes, we identified a combination of only three factors, Ascl1, Brn2 (also called Pou3f2) and Myt1l, that suffice to rapidly and efficiently convert mouse embryonic and postnatal fibroblasts into functional neurons in vitro. These induced neuronal (iN) cells express multiple neuron-specific proteins, generate action potentials and form functional synapses. Generation of iN cells from non-neural lineages could have important implications for studies of neural development, neurological disease modelling and regenerative medicine.", "title": "Direct conversion of fibroblasts to functional neurons by defined factors" }, { "docid": "461550", "text": "Functional elucidation of causal genetic variants and elements requires precise genome editing technologies. The type II prokaryotic CRISPR (clustered regularly interspaced short palindromic repeats)/Cas adaptive immune system has been shown to facilitate RNA-guided site-specific DNA cleavage. We engineered two different type II CRISPR/Cas systems and demonstrate that Cas9 nucleases can be directed by short RNAs to induce precise cleavage at endogenous genomic loci in human and mouse cells. Cas9 can also be converted into a nicking enzyme to facilitate homology-directed repair with minimal mutagenic activity. Lastly, multiple guide sequences can be encoded into a single CRISPR array to enable simultaneous editing of several sites within the mammalian genome, demonstrating easy programmability and wide applicability of the RNA-guided nuclease technology.", "title": "Multiplex genome engineering using CRISPR/Cas systems." }, { "docid": "4679264", "text": "The role of DNA cytosine methylation, an epigenetic regulator of chromatin structure and function, during normal and pathological brain development and aging remains unclear. Here, we examined by MethyLight PCR the DNA methylation status at 50 loci, encompassing primarily 5′ CpG islands of genes related to CNS growth and development, in temporal neocortex of 125 subjects ranging in age from 17 weeks of gestation to 104 years old. Two psychiatric disease cohorts—defined by chronic neurodegeneration (Alzheimer's) or lack thereof (schizophrenia)—were included. A robust and progressive rise in DNA methylation levels across the lifespan was observed for 8/50 loci (GABRA2, GAD1, HOXA1, NEUROD1, NEUROD2, PGR, STK11, SYK) typically in conjunction with declining levels of the corresponding mRNAs. Another 16 loci were defined by a sharp rise in DNA methylation levels within the first few months or years after birth. Disease-associated changes were limited to 2/50 loci in the Alzheimer's cohort, which appeared to reflect an acceleration of the age-related change in normal brain. Additionally, methylation studies on sorted nuclei provided evidence for bidirectional methylation events in cortical neurons during the transition from childhood to advanced age, as reflected by significant increases at 3, and a decrease at 1 of 10 loci. Furthermore, the DNMT3a de novo DNA methyl-transferase was expressed across all ages, including a subset of neurons residing in layers III and V of the mature cortex. Therefore, DNA methylation is dynamically regulated in the human cerebral cortex throughout the lifespan, involves differentiated neurons, and affects a substantial portion of genes predominantly by an age-related increase.", "title": "DNA Methylation in the Human Cerebral Cortex Is Dynamically Regulated throughout the Life Span and Involves Differentiated Neurons" }, { "docid": "4459491", "text": "Alzheimer’s disease is the most common form of dementia, characterized by two pathological hallmarks: amyloid-β plaques and neurofibrillary tangles. The amyloid hypothesis of Alzheimer’s disease posits that the excessive accumulation of amyloid-β peptide leads to neurofibrillary tangles composed of aggregated hyperphosphorylated tau. However, to date, no single disease model has serially linked these two pathological events using human neuronal cells. Mouse models with familial Alzheimer’s disease (FAD) mutations exhibit amyloid-β-induced synaptic and memory deficits but they do not fully recapitulate other key pathological events of Alzheimer’s disease, including distinct neurofibrillary tangle pathology. Human neurons derived from Alzheimer’s disease patients have shown elevated levels of toxic amyloid-β species and phosphorylated tau but did not demonstrate amyloid-β plaques or neurofibrillary tangles. Here we report that FAD mutations in β-amyloid precursor protein and presenilin 1 are able to induce robust extracellular deposition of amyloid-β, including amyloid-β plaques, in a human neural stem-cell-derived three-dimensional (3D) culture system. More importantly, the 3D-differentiated neuronal cells expressing FAD mutations exhibited high levels of detergent-resistant, silver-positive aggregates of phosphorylated tau in the soma and neurites, as well as filamentous tau, as detected by immunoelectron microscopy. Inhibition of amyloid-β generation with β- or γ-secretase inhibitors not only decreased amyloid-β pathology, but also attenuated tauopathy. We also found that glycogen synthase kinase 3 (GSK3) regulated amyloid-β-mediated tau phosphorylation. We have successfully recapitulated amyloid-β and tau pathology in a single 3D human neural cell culture system. Our unique strategy for recapitulating Alzheimer’s disease pathology in a 3D neural cell culture model should also serve to facilitate the development of more precise human neural cell models of other neurodegenerative disorders.", "title": "A three-dimensional human neural cell culture model of Alzheimer’s disease" }, { "docid": "6397191", "text": "Endothelin-1 (ET-1) is the predominant endothelin isopeptide generated by the vascular wall and therefore appears to be the most important peptide involved in regulation of cardiovascular events. Many pathologic conditions are associated with elevations of ET-1 in the blood vessel wall. Because these conditions are often cytokine driven, we examined the effects of a mixture of cytokines on ET-1 production in human vascular smooth muscle cells (VSMCs) derived from internal mammary artery and saphenous vein (SV). Incubation of IMA and SV VSMCs with tumor necrosis factor-alpha (10 ng/ml) and interferon-gamma (1000 U/ml) in combination for up to 48 h markedly elevated the expression of mRNA for prepro-ET-1 and the release of ET-1 into the culture medium. This cytokine-stimulated release of ET-1 was inhibited by a series of dual endothelin-converting enzyme (ECE)/neutral endopeptidase inhibitors, phosphoramidon, CGS 26303, and CGS 26393, with an accompanying increase in big ET-1 release but with no effect on expression of mRNA for prepro-ET-1. These same compounds were 10 times more potent at inhibiting the conversion of exogenously applied big ET-1 to ET-1. ECE-1b/c mRNA is present in SV VSMCs, however no ECE-1a is present in these cells. Thus VSMCs most probably contain, like endothelial cells, an intracellular ECE responsible for the endogenous synthesis of ET-1. Under the influence of pro-inflammatory mediators the vascular smooth muscle can therefore become an important site of ET-1 production, as has already been established for the dilator mediators nitric oxide, prostaglandin I2, and prostaglandin E2.", "title": "Endothelin-1 is induced by cytokines in human vascular smooth muscle cells: evidence for intracellular endothelin-converting enzyme." }, { "docid": "4347374", "text": "Viral replication usually requires that innate intracellular lines of defence be overcome, a task usually accomplished by specialized viral gene products. The virion infectivity factor (Vif) protein of human immunodeficiency virus (HIV) is required during the late stages of viral production to counter the antiviral activity of APOBEC3G (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G; also known as CEM15), a protein expressed notably in human T lymphocytes. When produced in the presence of APOBEC3G, vif-defective virus is non-infectious. APOBEC3G is closely related to APOBEC1, the central component of an RNA-editing complex that deaminates a cytosine residue in apoB messenger RNA. APOBEC family members also have potent DNA mutator activity through dC deamination; however, whether the editing potential of APOBEC3G has any relevance to HIV inhibition is unknown. Here, we demonstrate that it does, as APOBEC3G exerts its antiviral effect during reverse transcription to trigger G-to-A hypermutation in the nascent retroviral DNA. We also find that APOBEC3G can act on a broad range of retroviruses in addition to HIV, suggesting that hypermutation by editing is a general innate defence mechanism against this important group of pathogens.", "title": "Broad antiretroviral defence by human APOBEC3G through lethal editing of nascent reverse transcripts" }, { "docid": "9217800", "text": "The fatal adult motor neuron disease amyotrophic lateral sclerosis (ALS) shares some clinical and pathological overlap with frontotemporal dementia (FTD), an early-onset neurodegenerative disorder. The RNA/DNA-binding proteins fused in sarcoma (FUS; also known as TLS) and TAR DNA binding protein-43 (TDP-43) have recently been shown to be genetically and pathologically associated with familial forms of ALS and FTD. It is currently unknown whether perturbation of these proteins results in disease through mechanisms that are independent of normal protein function or via the pathophysiological disruption of molecular processes in which they are both critical. Here, we report that Drosophila mutants in which the homolog of FUS is disrupted exhibit decreased adult viability, diminished locomotor speed, and reduced life span compared with controls. These phenotypes were fully rescued by wild-type human FUS, but not ALS-associated mutant FUS proteins. A mutant of the Drosophila homolog of TDP-43 had similar, but more severe, deficits. Through cross-rescue analysis, we demonstrated that FUS acted together with and downstream of TDP-43 in a common genetic pathway in neurons. Furthermore, we found that these proteins associated with each other in an RNA-dependent complex. Our results establish that FUS and TDP-43 function together in vivo and suggest that molecular pathways requiring the combined activities of both of these proteins may be disrupted in ALS and FTD.", "title": "The ALS-associated proteins FUS and TDP-43 function together to affect Drosophila locomotion and life span." }, { "docid": "47018050", "text": "Here, we report that genome editing by CRISPR–Cas9 induces a p53-mediated DNA damage response and cell cycle arrest in immortalized human retinal pigment epithelial cells, leading to a selection against cells with a functional p53 pathway. Inhibition of p53 prevents the damage response and increases the rate of homologous recombination from a donor template. These results suggest that p53 inhibition may improve the efficiency of genome editing of untransformed cells and that p53 function should be monitored when developing cell-based therapies utilizing CRISPR–Cas9. CRISPR–Cas9-induced DNA damage triggers p53 to limit the efficiency of gene editing in immortalized human retinal pigment epithelial cells.", "title": "CRISPR–Cas9 genome editing induces a p53-mediated DNA damage response" }, { "docid": "7029990", "text": "One type of RNA editing involves the conversion of adenosine residues into inosine in double-stranded RNA through the action of adenosine deaminases acting on RNA (ADAR). A-to-I RNA editing of the coding sequence could result in synthesis of proteins not directly encoded in the genome. ADAR edits also non-coding sequences of target RNAs, such as introns and 3'-untranslated regions, which may affect splicing, translation, and mRNA stability. Three mammalian ADAR gene family members (ADAR1-3) have been identified. Here we investigated phenotypes of mice homozygous for ADAR1 null mutation. Although live ADAR1-/- embryos with normal gross appearance could be recovered up to E11.5, widespread apoptosis was detected in many tissues. Fibroblasts derived from ADAR1-/- embryos were also prone to apoptosis induced by serum deprivation. Our results demonstrate an essential requirement for ADAR1 in embryogenesis and suggest that it functions to promote survival of numerous tissues by editing one or more double-stranded RNAs required for protection against stress-induced apoptosis.", "title": "Stress-induced apoptosis associated with null mutation of ADAR1 RNA editing deaminase gene." }, { "docid": "4462919", "text": "The RNA-guided endonuclease Cas9 has emerged as a versatile genome-editing platform. However, the size of the commonly used Cas9 from Streptococcus pyogenes (SpCas9) limits its utility for basic research and therapeutic applications that use the highly versatile adeno-associated virus (AAV) delivery vehicle. Here, we characterize six smaller Cas9 orthologues and show that Cas9 from Staphylococcus aureus (SaCas9) can edit the genome with efficiencies similar to those of SpCas9, while being more than 1 kilobase shorter. We packaged SaCas9 and its single guide RNA expression cassette into a single AAV vector and targeted the cholesterol regulatory gene Pcsk9 in the mouse liver. Within one week of injection, we observed >40% gene modification, accompanied by significant reductions in serum Pcsk9 and total cholesterol levels. We further assess the genome-wide targeting specificity of SaCas9 and SpCas9 using BLESS, and demonstrate that SaCas9-mediated in vivo genome editing has the potential to be efficient and specific.", "title": "In vivo genome editing using Staphylococcus aureus Cas9" }, { "docid": "29107180", "text": "The structure of the human gene encoding the double-stranded RNA (dsRNA) adenosine deaminase (DRADA) was characterized. This nuclear localized enzyme is involved in the RNA editing required for the expression of certain subtypes of glutamate-gated ion channel subunits. The DRADA gene span 30 kb pairs and harbors 15 exons. The transcription of the DRADA gene driven by the putative promoter region, which contains no typical TATA or CCAAT box-like sequences, is initiated at multiple sites, 164 to 216 nucleotides upstream of the translation initiation codon. The three dsRNA binding motifs (DRBM), 70 amino acid residues long, are each encoded by two exons plus an intervening sequence that interrupts the motif at the identical amino acid position. This finding is consistent with the notion that the dsRNA binding domains may be composed of two separate functional subdomains. Fluorescent in situ hybridization localized the DRADA gene on the long arm chromosome 1, region q21. The gene structure and sequence information reported in this study will facilitate the investigation of involvement of DRADA in hereditary diseases that may be the result of malfunction of glutamate-gated ion channels.", "title": "Genomic organization and chromosomal location of the human dsRNA adenosine deaminase gene: the enzyme for glutamate-activated ion channel RNA editing." }, { "docid": "13969173", "text": "Amyotrophic lateral sclerosis (ALS) causes motor neuron degeneration, paralysis, and death. Accurate disease modeling, identifying disease mechanisms, and developing therapeutics is urgently needed. We previously reported motor neuron toxicity through postmortem ALS spinal cord-derived astrocytes. However, these cells can only be harvested after death, and their expansion is limited. We now report a rapid, highly reproducible method to convert adult human fibroblasts from living ALS patients to induced neuronal progenitor cells and subsequent differentiation into astrocytes (i-astrocytes). Non-cell autonomous toxicity to motor neurons is found following coculture of i-astrocytes from familial ALS patients with mutation in superoxide dismutase or hexanucleotide expansion in C9orf72 (ORF 72 on chromosome 9) the two most frequent causes of ALS. Remarkably, i-astrocytes from sporadic ALS patients are as toxic as those with causative mutations, suggesting a common mechanism. Easy production and expansion of i-astrocytes now enables rapid disease modeling and high-throughput drug screening to alleviate astrocyte-derived toxicity.", "title": "Direct conversion of patient fibroblasts demonstrates non-cell autonomous toxicity of astrocytes to motor neurons in familial and sporadic ALS." }, { "docid": "8790729", "text": "BACKGROUND There is a widespread interest in developing renewable sources of islet-replacement tissue for type I diabetes mellitus. Human mesenchymal cells isolated from the Wharton's jelly of the umbilical cord (HUMSCs), which can be easily obtained and processed compared with embryonic and bone marrow stem cells, possess stem cell properties. HUMSCs may be a valuable source for the generation of islets. \n METHODOLOGY AND PRINCIPAL FINDINGS HUMSCs were induced to transform into islet-like cell clusters in vitro through stepwise culturing in neuron-conditioned medium. To assess the functional stability of the islet-like cell clusters in vivo, these cell clusters were transplanted into the liver of streptozotocin-induced diabetic rats via laparotomy. Glucose tolerance was measured on week 12 after transplantation accompanied with immunohistochemistry and electron microscopy analysis. These islet-like cell clusters were shown to contain human C-peptide and release human insulin in response to physiological glucose levels. Real-time RT-PCR detected the expressions of insulin and other pancreatic beta-cell-related genes (Pdx1, Hlxb9, Nkx2.2, Nkx6.1, and Glut-2) in these islet-like cell clusters. The hyperglycemia and glucose intolerance in streptozotocin-induced diabetic rats was significantly alleviated after xenotransplantation of islet-like cell clusters, without the use of immunosuppressants. In addition to the existence of islet-like cell clusters in the liver, some special fused liver cells were also found, which characterized by human insulin and nuclei-positive staining and possessing secretory granules. \n CONCLUSIONS AND SIGNIFICANCE In this study, we successfully differentiate HUMSCs into mature islet-like cell clusters, and these islet-like cell clusters possess insulin-producing ability in vitro and in vivo. HUMSCs in Wharton's Jelly of the umbilical cord seem to be the preferential source of stem cells to convert into insulin-producing cells, because of the large potential donor pool, its rapid availability, no risk of discomfort for the donor, and low risk of rejection.", "title": "Islet-Like Clusters Derived from Mesenchymal Stem Cells in Wharton's Jelly of the Human Umbilical Cord for Transplantation to Control Type 1 Diabetes" }, { "docid": "39545358", "text": "Neuregulin 1 (NRG1) and its receptor ErbB4 are both susceptibility genes of schizophrenia. However, little is known about the underlying mechanisms of their malfunction. Although ErbB4 is enriched in GABAergic interneurons, the role of NRG1 in excitatory synapse formation in these neurons remains poorly understood. We showed that NRG1 increased both the number and size of PSD-95 puncta and the frequency and amplitude of miniature EPSCs (mEPSCs) in GABAergic interneurons, indicating that NRG1 stimulates the formation of new synapses and strengthens existing synapses. In contrast, NRG1 treatment had no effect on either the number or size of excitatory synapses in glutamatergic neurons, suggesting its synaptogenic effect is specific to GABAergic interneurons. Ecto-ErbB4 treatment diminished both the number and size of excitatory synapses, suggesting that endogenous NRG1 may be critical for basal synapse formation. NRG1 could stimulate the stability of PSD-95 in the manner that requires tyrosine kinase activity of ErbB4. Finally, deletion of ErbB4 in parvalbumin-positive interneurons led to reduced frequency and amplitude of mEPSCs, providing in vivo evidence that ErbB4 is important in excitatory synaptogenesis in interneurons. Together, our findings suggested a novel synaptogenic role of NRG1 in excitatory synapse development, possibly via stabilizing PSD-95, and this effect is specific to GABAergic interneurons. In light of the association of the genes of both NRG1 and ErbB4 with schizophrenia and dysfunction of GABAergic system in this disorder, these results provide insight into its potential pathological mechanism.", "title": "Neuregulin 1 promotes excitatory synapse development and function in GABAergic interneurons." }, { "docid": "40666943", "text": "PURPOSE To perform a systematic review on the epidemiology, the health-related quality of life (HRQoL) and economic burden of binge eating disorder (BED). \n METHODS A systematic literature search of English-language articles was conducted using Medline, Embase, PsycINFO, PsycARTICLES, Academic Search Complete, CINAHL Plus, Business Source Premier and Cochrane Library. Literature search on epidemiology was limited to studies published between 2009 and 2013. Cost data were inflated and converted to 2012 US$ purchasing power parities. All of the included studies were assessed for quality. \n RESULTS Forty-nine articles were included. Data on epidemiology were reported in 31, HRQoL burden in 16, and economic burden in 7 studies. Diagnosis of BED was made using 4th Edition of The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria in 46 studies. Lifetime prevalence of BED was 1.1-1.9% in the general population (DSM-IV). BED was associated with significant impairment in aspects of HRQoL relating to both physical and mental health; the Short Form 36 Physical and Mental Component Summary mean scores varied between 31.1 to 47.3 and 32.0 to 49.8, respectively. Compared to individuals without eating disorder, BED was related to increased healthcare utilization and costs. Annual direct healthcare costs per BED patient ranged between $2,372 and $3,731. \n CONCLUSIONS BED is a serious eating disorder that impairs HRQoL and is related to increased healthcare utilization and healthcare costs. The limited literature warrants further research, especially to better understand the long-term HRQoL and economic burden of BED.", "title": "Epidemiology, health-related quality of life and economic burden of binge eating disorder: a systematic literature review" } ]

[ { "docid": "15048300", "text": "BACKGROUND Data on absolute risks of outcomes and patterns of drug use in cost-effectiveness analyses are often based on randomised clinical trials (RCTs). The objective of this study was to evaluate the external validity of published cost-effectiveness studies by comparing the data used in these studies (typically based on RCTs) to observational data from actual clinical practice. Selective Cox-2 inhibitors (coxibs) were used as an example. \n METHODS AND FINDINGS The UK General Practice Research Database (GPRD) was used to estimate the exposure characteristics and individual probabilities of upper gastrointestinal (GI) events during current exposure to nonsteroidal anti-inflammatory drugs (NSAIDs) or coxibs. A basic cost-effectiveness model was developed evaluating two alternative strategies: prescription of a conventional NSAID or coxib. Outcomes included upper GI events as recorded in GPRD and hospitalisation for upper GI events recorded in the national registry of hospitalisations (Hospital Episode Statistics) linked to GPRD. Prescription costs were based on the prescribed number of tables as recorded in GPRD and the 2006 cost data from the British National Formulary. The study population included over 1 million patients prescribed conventional NSAIDs or coxibs. Only a minority of patients used the drugs long-term and daily (34.5% of conventional NSAIDs and 44.2% of coxibs), whereas coxib RCTs required daily use for at least 6-9 months. The mean cost of preventing one upper GI event as recorded in GPRD was US$104k (ranging from US$64k with long-term daily use to US$182k with intermittent use) and US$298k for hospitalizations. The mean costs (for GPRD events) over calendar time were US$58k during 1990-1993 and US$174k during 2002-2005. Using RCT data rather than GPRD data for event probabilities, the mean cost was US$16k with the VIGOR RCT and US$20k with the CLASS RCT. \n CONCLUSIONS The published cost-effectiveness analyses of coxibs lacked external validity, did not represent patients in actual clinical practice, and should not have been used to inform prescribing policies. External validity should be an explicit requirement for cost-effectiveness analyses.", "title": "A Comparison of Cost Effectiveness Using Data from Randomized Trials or Actual Clinical Practice: Selective Cox-2 Inhibitors as an Example" } ]

[ { "docid": "13625993", "text": "OBJECTIVE To determine the effectiveness and cost effectiveness of using information from circulating biomarkers to inform the prioritisation process of patients with stable angina awaiting coronary artery bypass graft surgery. \n DESIGN Decision analytical model comparing four prioritisation strategies without biomarkers (no formal prioritisation, two urgency scores, and a risk score) and three strategies based on a risk score using biomarkers: a routinely assessed biomarker (estimated glomerular filtration rate), a novel biomarker (C reactive protein), or both. The order in which to perform coronary artery bypass grafting in a cohort of patients was determined by each prioritisation strategy, and mean lifetime costs and quality adjusted life years (QALYs) were compared. \n DATA SOURCES Swedish Coronary Angiography and Angioplasty Registry (9935 patients with stable angina awaiting coronary artery bypass grafting and then followed up for cardiovascular events after the procedure for 3.8 years), and meta-analyses of prognostic effects (relative risks) of biomarkers. \n RESULTS The observed risk of cardiovascular events while on the waiting list for coronary artery bypass grafting was 3 per 10,000 patients per day within the first 90 days (184 events in 9935 patients). Using a cost effectiveness threshold of pound20,000- pound30,000 (euro22,000-euro33,000; $32,000-$48,000) per additional QALY, a prioritisation strategy using a risk score with estimated glomerular filtration rate was the most cost effective strategy (cost per additional QALY was < pound410 compared with the Ontario urgency score). The impact on population health of implementing this strategy was 800 QALYs per 100,000 patients at an additional cost of pound 245,000 to the National Health Service. The prioritisation strategy using a risk score with C reactive protein was associated with lower QALYs and higher costs compared with a risk score using estimated glomerular filtration rate. \n CONCLUSION Evaluating the cost effectiveness of prognostic biomarkers is important even when effects at an individual level are small. Formal prioritisation of patients awaiting coronary artery bypass grafting using a routinely assessed biomarker (estimated glomerular filtration rate) along with simple, routinely collected clinical information was cost effective. Prioritisation strategies based on the prognostic information conferred by C reactive protein, which is not currently measured in this context, or a combination of C reactive protein and estimated glomerular filtration rate, is unlikely to be cost effective. The widespread practice of using only implicit or informal means of clinically ordering the waiting list may be harmful and should be replaced with formal prioritisation approaches.", "title": "Assessing the cost effectiveness of using prognostic biomarkers with decision models: case study in prioritising patients waiting for coronary artery surgery" }, { "docid": "1287809", "text": "IMPORTANCE The American College of Cardiology and the American Heart Association (ACC/AHA) cholesterol treatment guidelines have wide-scale implications for treating adults without history of atherosclerotic cardiovascular disease (ASCVD) with statins. \n OBJECTIVE To estimate the cost-effectiveness of various 10-year ASCVD risk thresholds that could be used in the ACC/AHA cholesterol treatment guidelines. \n DESIGN, SETTING, AND PARTICIPANTS Microsimulation model, including lifetime time horizon, US societal perspective, 3% discount rate for costs, and health outcomes. In the model, hypothetical individuals from a representative US population aged 40 to 75 years received statin treatment, experienced ASCVD events, and died from ASCVD-related or non-ASCVD-related causes based on ASCVD natural history and statin treatment parameters. Data sources for model parameters included National Health and Nutrition Examination Surveys, large clinical trials and meta-analyses for statin benefits and treatment, and other published sources. \n MAIN OUTCOMES AND MEASURES Estimated ASCVD events prevented and incremental costs per quality-adjusted life-year (QALY) gained. \n RESULTS In the base-case scenario, the current ASCVD threshold of 7.5% or higher, which was estimated to be associated with 48% of adults treated with statins, had an incremental cost-effectiveness ratio (ICER) of $37,000/QALY compared with a 10% or higher threshold. More lenient ASCVD thresholds of 4.0% or higher (61% of adults treated) and 3.0% or higher (67% of adults treated) had ICERs of $81,000/QALY and $140,000/QALY, respectively. Shifting from a 7.5% or higher ASCVD risk threshold to a 3.0% or higher ASCVD risk threshold was estimated to be associated with an additional 161,560 cardiovascular disease events averted. Cost-effectiveness results were sensitive to changes in the disutility associated with taking a pill daily, statin price, and the risk of statin-induced diabetes. In probabilistic sensitivity analysis, there was a higher than 93% chance that the optimal ASCVD threshold was 5.0% or lower using a cost-effectiveness threshold of $100,000/QALY. \n CONCLUSIONS AND RELEVANCE In this microsimulation model of US adults aged 45 to 75 years [corrected], the current 10-year ASCVD risk threshold (≥7.5% risk threshold) used in the ACC/AHA cholesterol treatment guidelines has an acceptable cost-effectiveness profile (ICER, $37,000/QALY), but more lenient ASCVD thresholds would be optimal using cost-effectiveness thresholds of $100,000/QALY (≥4.0% risk threshold) or $150,000/QALY (≥3.0% risk threshold). The optimal ASCVD threshold was sensitive to patient preferences for taking a pill daily, changes to statin price, and the risk of statin-induced diabetes.", "title": "Cost-effectiveness of 10-Year Risk Thresholds for Initiation of Statin Therapy for Primary Prevention of Cardiovascular Disease." }, { "docid": "95102458", "text": "Abstract Several processes for the production and recovery of poly(3-hydroxybutyrate) (PHB) by Alcaligenes eutrophus, Alcaligenes latus, Methylobacterium organophilum, and recombinant Escherichia coli were designed based on the previously reported data and analyzed by computer-aided bioprocess design. PHB productivity, content, and yield significantly affected the final price of PHB. For the annual production of 2,850 tonnes of purified PHB, the process employing A. eutrophus with the recovery method of surfactant-hypochlorite digestion resulted in lowest price of PHB, $ 5.58/kg. As the production scale increased to one million tonnes per year, the price of PHB dropped to $ 4.75/kg. The cost of carbon substrate significantly affected the overall economics in large production scale. Therefore, the production cost can be considerably lowered when agricultural wastes, such as whey and molasses, are used.", "title": "Process analysis and economic evaluation for Poly(3-hydroxybutyrate) production by fermentation" }, { "docid": "16812091", "text": "CONTEXT Osteoporosis causes substantial morbidity and costs $13.8 billion annually in the United States. Measurement of bone mass by densitometry is a primary part of diagnosing osteoporosis and deciding a preventive treatment course. Bone mineral densitometry has become more widely available and commonly used in practice. \n OBJECTIVE To review evidence about the value of various clinical applications of bone densitometry. \n DATA SOURCES A MEDLINE search was performed to update previous meta-analyses of the relationship between various measurements of bone density and risk of vertebral and hip fracture. We used data from the prospective Study of Osteoporotic Fractures to estimate risk of fracture from bone density and age in postmenopausal women. STUDY SELECTION AND DATA EXTRACTION When available, meta-analyses and systematic reviews are emphasized in the review. \n DATA SYNTHESIS Bone mineral density (BMD) predicts fracture and can be used in combination with age to estimate absolute risk of fractures in postmenopausal white women. Hip BMD predicts hip fracture more strongly than other measurements of BMD. There are insufficient data to translate BMD results into risk of fracture for men and nonwhite women. The benefits of treatments to prevent fractures depend on BMD: women with osteoporosis have a greater risk of fractures and greater benefit from treatments than women without osteoporosis. \n CONCLUSIONS Guidelines based on systematic reviews and a cost-effectiveness analysis have suggested that it is worthwhile to measure BMD in white women older than 65 years and perhaps to use risk factors to select younger postmenopausal women for densitometry. Other potential clinical applications of BMD that have not yet been adequately studied include screening men or nonwhite women, monitoring BMD in patients receiving treatment, and using BMD to identify patients who should be evaluated for secondary causes of osteoporosis.", "title": "Clinical use of bone densitometry: scientific review." }, { "docid": "5151024", "text": "BACKGROUND The diagnosis of hypertension has traditionally been based on blood-pressure measurements in the clinic, but home and ambulatory measurements better correlate with cardiovascular outcome, and ambulatory monitoring is more accurate than both clinic and home monitoring in diagnosing hypertension. We aimed to compare the cost-effectiveness of different diagnostic strategies for hypertension. \n METHODS We did a Markov model-based probabilistic cost-effectiveness analysis. We used a hypothetical primary-care population aged 40 years or older with a screening blood-pressure measurement greater than 140/90 mm Hg and risk-factor prevalence equivalent to the general population. We compared three diagnostic strategies-further blood pressure measurement in the clinic, at home, and with an ambulatory monitor-in terms of lifetime costs, quality-adjusted life years, and cost-effectiveness. \n FINDINGS Ambulatory monitoring was the most cost-effective strategy for the diagnosis of hypertension for men and women of all ages. It was cost-saving for all groups (from -£56 [95% CI -105 to -10] in men aged 75 years to -£323 [-389 to -222] in women aged 40 years) and resulted in more quality-adjusted life years for men and women older than 50 years (from 0·006 [0·000 to 0·015] for women aged 60 years to 0·022 [0·012 to 0·035] for men aged 70 years). This finding was robust when assessed with a wide range of deterministic sensitivity analyses around the base case, but was sensitive if home monitoring was judged to have equal test performance to ambulatory monitoring or if treatment was judged effective irrespective of whether an individual was hypertensive. \n INTERPRETATION Ambulatory monitoring as a diagnostic strategy for hypertension after an initial raised reading in the clinic would reduce misdiagnosis and save costs. Additional costs from ambulatory monitoring are counterbalanced by cost savings from better targeted treatment. Ambulatory monitoring is recommended for most patients before the start of antihypertensive drugs. \n FUNDING National Institute for Health Research and the National Institute for Health and Clinical Excellence.", "title": "Cost-effectiveness of options for the diagnosis of high blood pressure in primary care: a modelling study." }, { "docid": "6748318", "text": "BACKGROUND In Spain, prophylactic vaccination against human papillomavirus (HPV) types 16 and 18 is being offered free-of-charge to one birth cohort of girls aged 11-14. Screening is opportunistic (annual/biannual) contributing to social and geographical disparities. \n METHODS A multi-HPV-type microsimulation model was calibrated to epidemiologic data from Spain utilising likelihood-based methods to assess the health and economic impact of adding HPV vaccination to cervical cancer screening. Strategies included (1) screening alone of women over age 25, varying frequency (every 1-5 years) and test (cytology, HPV DNA testing); (2) HPV vaccination of 11-year-old girls combined with screening. Outcomes included lifetime cancer risk, life expectancy, lifetime costs, number of clinical procedures and incremental cost-effectiveness ratios. \n RESULTS After the introduction of HPV vaccination, screening will need to continue, and strategies that incorporated HPV testing are more effective and cost-effective than those with cytology alone. For vaccinated girls, 5-year organised cytology with HPV testing as triage from ages 30 to 65 costs 24,350€ per year of life saved (YLS), assuming life-long vaccine immunity against HPV-16/18 by 3 doses with 90% coverage. Unvaccinated girls would benefit from organised cytology screening with HPV testing as triage; 5-year screening from ages 30 to 65 costs 16,060€/YLS and 4-year screening from ages 30 to 85 costs 38,250€/YLS. Interventions would be cost-effective depending on the cost-effectiveness threshold and the vaccine price. \n CONCLUSIONS In Spain, inequitable coverage and overuse of cytology make screening programmes inefficient. If high vaccination coverage among pre-adolescent girls is achieved, organised cytology screening with HPV triage starting at ages 30 to at least 65 every 4-5 years represents the best balance between costs and benefits.", "title": "Cost-effectiveness of human papillomavirus vaccination and screening in Spain." }, { "docid": "23206239", "text": "The efficient diagnosis and accurate monitoring of diabetic patients are cornerstones for reducing the risk of diabetic complications. The current diagnostic and prognostic strategies in diabetes are mainly based on two tests, plasma (or capillary) glucose and glycated hemoglobin (HbA1c). Nevertheless, these measures are not foolproof, and their clinical usefulness is biased by a number of clinical and analytical factors. The introduction of other indices of glucose homeostasis in clinical practice such as fructosamine and glycated albumin (GA) may be regarded as an attractive alternative, especially in patients in whom the measurement of HbA1c may be biased or even unreliable. These include patients with rapid changes of glucose homeostasis and larger glycemic excursions, and patients with red blood cell disorders and renal disease. According to available evidence, the overall diagnostic efficiency of GA seems superior to that of fructosamine throughout a broad range of clinical settings. The current method for measuring GA is also better standardized and less vulnerable to preanalytical variables than those used for assessing fructosamine. Additional advantages of GA over HbA1c are represented by lower reagent cost and being able to automate the GA analysis on many conventional laboratory instruments. Although further studies are needed to definitely establish that GA can complement or even replace conventional measures of glycemic control such as HbA1c, GA may help the clinical management of patients with diabetes in whom HbA1c values might be unreliable.", "title": "Advantages and pitfalls of fructosamine and glycated albumin in the diagnosis and treatment of diabetes." }, { "docid": "3610080", "text": "OBJECTIVES To identify and describe misunderstandings between patients and doctors associated with prescribing decisions in general practice. \n DESIGN Qualitative study. \n SETTING 20 general practices in the West Midlands and south east England. \n PARTICIPANTS 20 general practitioners and 35 consulting patients. \n MAIN OUTCOME MEASURES Misunderstandings between patients and doctors that have potential or actual adverse consequences for taking medicine. \n RESULTS 14 categories of misunderstanding were identified relating to patient information unknown to the doctor, doctor information unknown to the patient, conflicting information, disagreement about attribution of side effects, failure of communication about doctor's decision, and relationship factors. All the misunderstandings were associated with lack of patients' participation in the consultation in terms of the voicing of expectations and preferences or the voicing of responses to doctors' decisions and actions. They were all associated with potential or actual adverse outcomes such as non-adherence to treatment. Many were based on inaccurate guesses and assumptions. In particular doctors seemed unaware of the relevance of patients' ideas about medicines for successful prescribing. \n CONCLUSIONS Patients' participation in the consultation and the adverse consequences of lack of participation are important. The authors are developing an educational intervention that builds on these findings.", "title": "Misunderstandings in prescribing decisions in general practice: qualitative study." }, { "docid": "24916604", "text": "BACKGROUND The use of bisphosphonates for the prevention of skeletal related events in women with bone metastases from breast cancer is well established. We undertook an evaluation of bisphosphonate use in clinical practice in three Canadian cancer centres. In addition we assessed whether or not physicians at these centres are following their local treatment guidelines and funding policies. \n METHODS Charts and electronic files of patients who had received either clodronate or pamidronate at any time between January 2000 and December 2001 at three Canadian cancer centres were retrospectively reviewed. \n RESULTS There has been a marked improvement in the time between the diagnosis of bone metastases and the commencement of bisphosphonates from a median of 155 days in 1998 to 24 days in 2001. However, despite a local funding policy requiring that oral clodronate be the first bisphosphonate used, this was the case in only 67% of patients. In addition, despite one centre's guidelines recommending that bisphosphonates be stopped once the patient was progressing, 90% of their patients remained on bisphosphonates until they died. \n CONCLUSIONS A considerable amount of effort is spent on the creation of \"evidence based\" treatment guidelines. Funding agencies develop policies based on these treatment guidelines, but often funding is more restrictive than the treatment guideline would suggest. It is clear from this review that physicians still appear to manage a substantial proportion of patients outside of funding policies, but within evidence based recommendations. Therefore, a need exists for either the creation of guidelines and policies that physicians will follow or the implementation of methods to ensure that restrictive policies are actually followed.", "title": "Do physicians follow systemic treatment and funding policy guidelines?" }, { "docid": "7757997", "text": "It has been estimated that approximately 37% of the US population judged to be at high risk for developing coronary artery disease (CAD), based on the National Cholesterol Education Program guidelines, have increased plasma lipoprotein(a) [Lp(a)], whereas Lp(a) is increased in only 14% of those judged to be at low risk. Therefore, the importance of establishing a better understanding of the relative contribution of Lp(a) to the risk burden for CAD and other forms of vascular disease, as well as the underlying mechanisms, is clearly evident. However, the structural complexity and size heterogeneity of Lp(a) have hindered the development of immunoassays to accurately measure Lp(a) concentrations in plasma. The large intermethod variation in Lp(a) values has made it difficult to compare data from different clinical studies and to achieve a uniform interpretation of clinical data. A workshop was recently convened by the National Heart, Lung, and Blood Institute (NHLBI) to evaluate our current understanding of Lp(a) as a risk factor for atherosclerotic disorders; to determine how future studies could be designed to more clearly define the extent to which, and mechanisms by which, Lp(a) participates in these processes; and to present the results of the NHLBI-supported program for the evaluation and standardization of Lp(a) immunoassays. This report includes the most recent data presented by the workshop participants and the resulting practical and research recommendations.", "title": "Report of the National Heart, Lung, and Blood Institute Workshop on Lipoprotein(a) and Cardiovascular Disease: recent advances and future directions." }, { "docid": "13843341", "text": "OBJECTIVE To evaluate the cost effectiveness of standard treatment with and without the addition of ward based non-invasive ventilation in patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease. \n DESIGN Incremental cost effectiveness analysis of a randomised controlled trial. \n SETTING Medical wards in 14 hospitals in the United Kingdom. \n PARTICIPANTS The trial comprised 236 patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease and mild to moderate acidosis (pH 7.25-7.35) secondary to respiratory failure. The economic analysis compared the costs of treatment that these patients received after randomisation. \n MAIN OUTCOME MEASURE Incremental cost per in-hospital death. \n RESULTS 24/118 died in the group receiving standard treatment and 12/118 in the group receiving non-invasive ventilation (P=0.05). Allocation to the group receiving non-invasive ventilation was associated with a reduction in costs of 49362 pounds sterling (78741 dollars; 73109 euros), mainly through reduced use of intensive care units. The incremental cost effectiveness ratio was -645 pounds sterling per death avoided (95% confidence interval -2310 pounds sterling to 386 pounds sterling), indicating a dominant (more effective and less costly) strategy. Modelling of these data indicates that a typical UK hospital providing a non-invasive ventilation service will avoid six deaths and three to nine admissions to intensive care units per year, with an associated cost reduction of 12000-53000 pounds sterling per year. \n CONCLUSIONS Non-invasive ventilation is a highly cost effective treatment that both reduced total costs and improved mortality in hospital.", "title": "Cost effectiveness of ward based non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease: economic analysis of randomised controlled trial." }, { "docid": "31612088", "text": "Efforts to improve the outcomes of patients with mental illness often have involved incorporating the skills of a variety of health care professionals into collaborative care models. For over 30 years, clinical pharmacists have contributed to these care models in capacities ranging from educator to consultant to provider. This systematic review evaluates the quantity and quality of medical literature examining the impact of pharmacists in mental health from 1972-2003. Although we identified approximately 35 publications describing the roles of clinical pharmacists in this regard, only 16 were of sufficient scientific rigor to permit evaluation and comparison. The 16 studies were divided equally between inpatient and outpatient settings and were conducted in a variety of health care organizations (e.g., Veterans Administration, health maintenance organizations, community mental health clinics, and nursing homes). Nine of the studies examined the role of pharmacists in providing treatment recommendations and patient education, five featured pharmacists as providers (with prescriptive authority), and the remaining two described the impact pharmacists have in delivering education to the psychiatric staff. Six of the 16 studies were prospective, but only three of these incorporated a randomization procedure for patients or facilities. Collectively, the results of the 16 studies were positive, demonstrating improvements in outcomes, prescribing practices, patient satisfaction, and resource use. Unfortunately, most of the investigations were small, and significant limitations in study design limited further comparison. Given the long history and anecdotal success of pharmacists in mental health care settings, additional multicenter cost-effectiveness trials are warranted to further support the role of the psychiatric pharmacist.", "title": "Evaluating the impact of pharmacists in mental health: a systematic review." }, { "docid": "2659805", "text": "A number of methods have been developed to assist subjects in providing an estimate of portion size but their application in improving portion size estimation by children has not been investigated systematically. The aim was to develop portion size assessment tools for use with children and to assess the accuracy of children's estimates of portion size using the tools. The tools were food photographs, food models and an interactive portion size assessment system (IPSAS). Children (n 201), aged 4-16 years, were supplied with known quantities of food to eat, in school. Food leftovers were weighed. Children estimated the amount of each food using each tool, 24 h after consuming the food. The age-specific portion sizes represented were based on portion sizes consumed by children in a national survey. Significant differences were found between the accuracy of estimates using the three tools. Children of all ages performed well using the IPSAS and food photographs. The accuracy and precision of estimates made using the food models were poor. For all tools, estimates of the amount of food served were more accurate than estimates of the amount consumed. Issues relating to reporting of foods left over which impact on estimates of the amounts of foods actually consumed require further study. The IPSAS has shown potential for assessment of dietary intake with children. Before practical application in assessment of dietary intake of children the tool would need to be expanded to cover a wider range of foods and to be validated in a 'real-life' situation.", "title": "Children's estimates of food portion size: the development and evaluation of three portion size assessment tools for use with children." }, { "docid": "25049067", "text": "OBJECTIVE To conduct an economic analysis of the Hlabisa community-based directly observed therapy management strategy for tuberculosis and to project costs of three alternative strategies. \n SETTING Hlabisa health district, KwaZulu-Natal, South Africa. \n METHODS An economic analysis comparing the current tuberculosis management strategy in Hlabisa with three alternative strategies (the Hlabisa strategy prior to 1991 based on hospitalisation, the national strategy and sanatorium care) in terms of costs to both health service and patient and of cost-effectiveness. \n RESULTS The current Hlabisa strategy was the most cost-effective (R3799 per patient cured), compared with R98307 for the strategy used prior to 1991, R9940 for the national strategy, and R11145 for sanatorium care. Between 71% and 88% of treatment costs lie with the health service, and hospitalisation (R119 per day) is the most expensive item. Prolonged hospitalisation is extremely expensive, but community care is cheaper (community clinic visit, R28; community health worker visit, R7). The total cost of supervising a patient in the community under the current Hlabisa strategy was R503, equivalent to 4.2 days in hospital. Drug costs (R157) are equivalent to just 1.3 days in hospital. \n CONCLUSION Cost to both health service and patient can be substantially reduced by using community-based directly observed therapy for tuberculosis, a strategy that is cheap and cost-effective in Hlabisa. These findings have important national implications, supporting the goals of the new tuberculosis control programme.", "title": "Costs and cost-effectiveness of alternative tuberculosis management strategies in South Africa--implications for policy." }, { "docid": "21377587", "text": "BACKGROUND Patient experience is increasingly used to assess organizational performance, for example in public reporting or pay-for-performance schemes. Conventional approaches using 95% confidence intervals are commonly used to determine required survey samples or to report performance but these may result in unreliable organizational comparisons. \n METHODS We analyzed data from 2.2 million patients who responded to the English 2009 General Practice Patient Survey, which included 45 patient experience questions nested within 6 different care domains (access, continuity of care, communication, anticipatory care planning, out-of-hours care, and overall care satisfaction). For each question, unadjusted and case-mix adjusted (for age, sex, and ethnicity) organization-level reliability, and intraclass correlation coefficients were calculated. \n RESULTS Mean responses per organization ranged from 23 to 256 for questions evaluating primary care practices, and from 1454 to 2758 for questions evaluating out-of-hours care organizations. Adjusted and unadjusted reliability values were similar. Twenty-six questions had excellent reliability (≥0.90). Seven nurse communication questions had very good reliability (≥0.85), but 3 anticipatory care planning questions had lower reliability (<0.70). Reliability was typically <0.70 for questions with <100 mean responses per practice, usually indicating questions which only a subset of patients were eligible to answer. Nine questions had both excellent reliability and high intraclass correlation coefficients (≥0.10) indicating both reliable measurement and substantial performance variability. \n CONCLUSIONS High reliability is a necessary property of indicators used to compare health care organizations. Using the English General Practice Patient Survey as a case study, we show how reliability and intraclass correlation coefficients can be used to select measures to support robust organizational comparisons, and to design surveys that will both provide high-quality measurement and optimize survey costs.", "title": "How can health care organizations be reliably compared?: Lessons from a national survey of patient experience." }, { "docid": "1986482", "text": "BACKGROUND Since November 2009, WHO recommends that adults infected with HIV should initiate antiretroviral therapy (ART) at CD4+ cell counts of ≤350 cells/µl rather than ≤200 cells/µl. South Africa decided to adopt this strategy for pregnant and TB co-infected patients only. We estimated the impact of fully adopting the new WHO guidelines on HIV epidemic dynamics and associated costs. \n METHODS AND FINDING We used an established model of the transmission and control of HIV in specified sexual networks and healthcare settings. We quantified the model to represent Hlabisa subdistrict, KwaZulu-Natal, South Africa. We predicted the HIV epidemic dynamics, number on ART and program costs under the new guidelines relative to treating patients at ≤200 cells/µl for the next 30 years. During the first five years, the new WHO treatment guidelines require about 7% extra annual investments, whereas 28% more patients receive treatment. Furthermore, there will be a more profound impact on HIV incidence, leading to relatively less annual costs after seven years. The resulting cumulative net costs reach a break-even point after on average 16 years. \n CONCLUSIONS Our study strengthens the WHO recommendation of starting ART at ≤350 cells/µl for all HIV-infected patients. Apart from the benefits associated with many life-years saved, a modest frontloading appears to lead to net savings within a limited time-horizon. This finding is robust to alternative assumptions and foreseeable changes in ART prices and effectiveness. Therefore, South Africa should aim at rapidly expanding its healthcare infrastructure to fully embrace the new WHO guidelines.", "title": "The Impact of the New WHO Antiretroviral Treatment Guidelines on HIV Epidemic Dynamics and Cost in South Africa" }, { "docid": "116556376", "text": "BACKGROUND Little information is available on physician characteristics and patient presentations that may influence compliance with evidence-based guidelines for acute low back pain. \n OBJECTIVE To assess whether physicians' management decisions are consistent with the Agency for Health Research Quality's guideline and whether responses varied with the presentation of sciatica or by physician characteristics. \n DESIGN Cross-sectional study using a mailed survey. \n PARTICIPANTS Participants were randomly selected from internal medicine, family practice, general practice, emergency medicine, and occupational medicine specialties. \n MEASUREMENTS A questionnaire asked for recommendations for 2 case scenarios, representing patients without and with sciatica, respectively. \n RESULTS Seven hundred and twenty surveys were completed (response rate=25%). In cases 1 (without sciatica) and 2 (with sciatica), 26.9% and 4.3% of physicians fully complied with the guideline, respectively. For each year in practice, the odds of guideline noncompliance increased 1.03 times (95% confidence interval [CI]=1.01 to 1.05) for case 1. With occupational medicine as the referent specialty, general practice had the greatest odds of noncompliance (3.60, 95% CI=1.75 to 7.40) in case 1, followed by internal medicine and emergency medicine. Results for case 2 reflected the influence of sciatica with internal medicine having substantially higher odds (vs case 1) and the greatest odds of noncompliance of any specialty (6.93, 95% CI=1.47 to 32.78), followed by family practice and emergency medicine. \n CONCLUSIONS A majority of primary care physicians continue to be noncompliant with evidence-based back pain guidelines. Sciatica dramatically influenced clinical decision-making, increasing the extent of noncompliance, particularly for internal medicine and family practice. Physicians' misunderstanding of sciatica's natural history and belief that more intensive initial management is indicated may be factors underlying the observed influence of sciatica.", "title": "Physicians' initial management of acute low back pain versus evidence-based guidelines. Influence of sciatica." }, { "docid": "38799797", "text": "Interventions by the pharmacists have always been considered as a valuable input by the health care community in the patient care process by reducing the medication errors, rationalizing the therapy and reducing the cost of therapy. The primary objective of this study was to determine the number and types of medication errors intervened by the dispensing pharmacists at OPD pharmacy in the Khoula Hospital during 2009 retrospectively. The interventions filed by the pharmacists and assistant pharmacists in OPD pharmacy were collected. Then they were categorized and analyzed after a detailed review. The results show that 72.3% of the interventions were minor of which 40.5% were about change medication order. Comparatively more numbers of prescriptions were intervened in female patients than male patients. 98.2% of the interventions were accepted by the prescribers reflecting the awareness of the doctors about the importance of the pharmacy practice. In this study only 688 interventions were due to prescribing errors of which 40.5% interventions were done in changing the medication order of clarifying the medicine. 14.9% of the interventions were related to administrative issues, 8.7% of the interventions were related to selection of medications as well as errors due to ignorance of history of patients. 8.2% of the interventions were to address the overdose of medications. Moderately significant interventions were observed in 19.4% and 7.5% of them were having the impact on major medication errors. Pharmacists have intervened 20.8% of the prescriptions to prevent complications, 25.1% were to rationalize the treatment, 7.9% of them were to improve compliance. Based on the results we conclude that the role of pharmacist in improving the health care system is vital. We recommend more number of such research based studies to bring awareness among health care professionals, provide solution to the prescription and dispensing problems, as it can also improve the documentation system, emphasize the importance of it, reduce prescribing errors, and update the knowledge of pharmacists and other health care professionals.", "title": "Interventions by pharmacists in out-patient pharmaceutical care." }, { "docid": "27024392", "text": "Cannabis has a potential for clinical use often obscured by unreliable and purely anecdotal reports. The most important natural cannabinoid is the psychoactive tetrahydrocannabinol (Δ9-THC); others include cannabidiol (CBD) and cannabigerol (CBG). Not all the observed effects can be ascribed to THC, and the other constituents may also modulate its action; for example CBD reduces anxiety induced by THC. A standardised extract of the herb may be therefore be more beneficial in practice and clinical trial protocols have been drawn up to assess this. The mechanism of action is still not fully understood, although cannabinoid receptors have been cloned and natural ligands identified. Cannabis is frequently used by patients with multiple sclerosis (MS) for muscle spasm and pain, and in an experimental model of MS low doses of cannabinoids alleviated tremor. Most of the controlled studies have been carried out with THC rather than cannabis herb and so do not mimic the usual clincal situation. Small clinical studies have confirmed the usefulness of THC as an analgesic; CBD and CBG also have analgesic and antiinflammatory effects, indicating that there is scope for developing drugs which do not have the psychoactive properties ofTHC. Patients taking the synthetic derivative nabilone for neurogenic pain actually preferred cannabis herb and reported that it relieved not only pain but the associated depression and anxiety. Cannabinoids are effective in chemotherapy-induced emesis and nabilone has been licensed for this use for several years. Currently, the synthetic cannabinoid HU211 is undergoing trials as a protective agent after brain trauma. Anecdotal reports of cannabis use include case studies in migraine and Tourette’s syndrome, and as a treatment for asthma and glaucoma. Apart from the smoking aspect, the safety profile of cannabis is fairly good. However, adverse reactions include panic or anxiety attacks, which are worse in the elderly and in women, and less likely in children. Although psychosis has been cited as a consequence of cannabis use, an examination of psychiatric hospital admissions found no evidence of this, however, it may exacerbate existing symptoms. The relatively slow elimination from the body of the cannabinoids has safety implications for cognitive tasks, especially driving and operating machinery; although driving impairment with cannabis is only moderate, there is a significant interaction with alcohol. Natural materials are highly variable and multiple components need to be standardised to ensure reproducible effects. Pure natural and synthetic compounds do not have these disadvantages but may not have the overall therapeutic effect of the herb.", "title": "Cannabinoids in Clinical Practice" } ]

[ { "docid": "15048300", "text": "BACKGROUND Data on absolute risks of outcomes and patterns of drug use in cost-effectiveness analyses are often based on randomised clinical trials (RCTs). The objective of this study was to evaluate the external validity of published cost-effectiveness studies by comparing the data used in these studies (typically based on RCTs) to observational data from actual clinical practice. Selective Cox-2 inhibitors (coxibs) were used as an example. \n METHODS AND FINDINGS The UK General Practice Research Database (GPRD) was used to estimate the exposure characteristics and individual probabilities of upper gastrointestinal (GI) events during current exposure to nonsteroidal anti-inflammatory drugs (NSAIDs) or coxibs. A basic cost-effectiveness model was developed evaluating two alternative strategies: prescription of a conventional NSAID or coxib. Outcomes included upper GI events as recorded in GPRD and hospitalisation for upper GI events recorded in the national registry of hospitalisations (Hospital Episode Statistics) linked to GPRD. Prescription costs were based on the prescribed number of tables as recorded in GPRD and the 2006 cost data from the British National Formulary. The study population included over 1 million patients prescribed conventional NSAIDs or coxibs. Only a minority of patients used the drugs long-term and daily (34.5% of conventional NSAIDs and 44.2% of coxibs), whereas coxib RCTs required daily use for at least 6-9 months. The mean cost of preventing one upper GI event as recorded in GPRD was US$104k (ranging from US$64k with long-term daily use to US$182k with intermittent use) and US$298k for hospitalizations. The mean costs (for GPRD events) over calendar time were US$58k during 1990-1993 and US$174k during 2002-2005. Using RCT data rather than GPRD data for event probabilities, the mean cost was US$16k with the VIGOR RCT and US$20k with the CLASS RCT. \n CONCLUSIONS The published cost-effectiveness analyses of coxibs lacked external validity, did not represent patients in actual clinical practice, and should not have been used to inform prescribing policies. External validity should be an explicit requirement for cost-effectiveness analyses.", "title": "A Comparison of Cost Effectiveness Using Data from Randomized Trials or Actual Clinical Practice: Selective Cox-2 Inhibitors as an Example" } ]

[ { "docid": "16705338", "text": "Chemical-protein interaction (CPI) is the central topic of target identification and drug discovery. However, large scale determination of CPI is a big challenge for in vitro or in vivo experiments, while in silico prediction shows great advantages due to low cost and high accuracy. On the basis of our previous drug-target interaction prediction via network-based inference (NBI) method, we further developed node- and edge-weighted NBI methods for CPI prediction here. Two comprehensive CPI bipartite networks extracted from ChEMBL database were used to evaluate the methods, one containing 17,111 CPI pairs between 4,741 compounds and 97 G protein-coupled receptors, the other including 13,648 CPI pairs between 2,827 compounds and 206 kinases. The range of the area under receiver operating characteristic curves was 0.73 to 0.83 for the external validation sets, which confirmed the reliability of the prediction. The weak-interaction hypothesis in CPI network was identified by the edge-weighted NBI method. Moreover, to validate the methods, several candidate targets were predicted for five approved drugs, namely imatinib, dasatinib, sertindole, olanzapine and ziprasidone. The molecular hypotheses and experimental evidence for these predictions were further provided. These results confirmed that our methods have potential values in understanding molecular basis of drug polypharmacology and would be helpful for drug repositioning.", "title": "Prediction of Chemical-Protein Interactions Network with Weighted Network-Based Inference Method" }, { "docid": "10749308", "text": "Placebo-controlled trials are used extensively in the development of new pharmaceuticals. They are sometimes challenged as unethical in settings in which patients could be treated with an existing therapy (1-7). The issues of when placebo controls are ethically acceptable and when they are scientifically necessary are important and worthy of discussion. The Ethics of Placebo Controls The Declaration of Helsinki The Declaration of Helsinki (8) is an international document that describes ethical principles for clinical investigation. Those who contend that placebo controls are unethical whenever known effective therapy exists for a condition usually cite the following sentence in the Declaration as support for that position: In any medical study, every patientincluding those of a control group, if anyshould be assured of the best proven diagnostic and therapeutic method. We believe that an interpretation of this sentence as barring placebo controls whenever an effective treatment exists is untenable. First, the requirement that all patients receive the best proven diagnostic and therapeutic method would bar not only placebo-controlled trials but also active-control and historically controlled trials. When effective treatment exists, the patient receiving the investigational treatment instead of the established therapy is clearly not getting the best proven treatment. Second, it does not seem reasonable to consider as equivalent all failures to use known effective therapy. Historically, concerns about placebo use have usually arisen in the context of serious illness. There is universal agreement that use of placebo or otherwise untreated controls is almost always unethical when therapy shown to improve survival or decrease serious morbidity is available. But in cases in which the treatment does not affect the patient's long-term health, an ethical imperative to use existing therapy is not plausible. Can it be, for example, that because topical minoxidil or oral finasteride can grow hair, a placebo-controlled trial of a new remedy for baldness is unethical? Is it really unethical to use placebos in short-term studies of drugs for allergic rhinitis, insomnia, anxiety, dermatoses, heartburn, or headaches in fully informed patients? We do not believe that there is a reasonable basis for arguing that such studies and many other placebo-controlled studies of symptom relief are unethical and that an informed patient cannot properly be asked to participate in them. Third, there is good reason to doubt that the cited phrase was intended to discourage placebo-controlled trials. The phrase under discussion was not part of the original 1964 Declaration but was added in 1975 to reinforce the idea that the physicianpatient relationship must be respected just as it would be in a purely therapeutic situation not involving research objectives (8). In the explanation accompanying the 1975 change, the issue of placebo-controlled trials was not even mentioned (9). The American Medical Association (10), the World Health Organization (11), and the Council for International Organizations of Medical Sciences (12) have rejected the position that the Declaration uniformly bars placebo-controlled trials when proven therapy is available. Informed Consent in Placebo-Controlled Trials Patients asked to participate in a placebo-controlled trial must be informed of the existence of any effective therapy, must be able to explore the consequences of deferring such therapy with the investigator, and must provide fully informed consent. Concern about whether consent to participate in trials is as informed as we would like to believe is valid, but these concerns apply as much to the patient's decision to forgo known effective treatment and risk exposure to a potentially ineffective or even harmful new agent in an active-control trial as to a decision to accept possible persistence of symptoms in a placebo-controlled trial. Thus, this problem is not unique to placebo-controlled trials. For the above reasons, we conclude that placebo-controlled trials may be ethically conducted even when effective therapy exists, as long as patients will not be harmed by participation and are fully informed about their alternatives. Although in many cases application of this standard will be fairly straightforward, in others it will not, and there may be debate about the consequences of deferring treatment (13). Assessment of Effectiveness with Active-Control Trials Clinical trials that, because of deficiencies in study design or conduct, are unlikely to provide scientifically valid and clinically meaningful results raise their own ethical concerns (12, 14). The remainder of this paper will address the inability of commonly proposed alternatives to placebo-controlled trials to evaluate the effectiveness of new treatments in many medical settings. Active-Control Equivalence Trials (Noninferiority Trials) The ability to conduct a placebo-controlled trial ethically in a given situation does not necessarily mean that placebo-controlled trials should be carried out when effective therapy exists. Patients and physicians might still prefer a trial in which every participant is given an active treatment. What remains to be examined is why placebo-controlled trials (or, more generally, trials intended to show an advantage of one treatment over another) are frequently needed to demonstrate the effectiveness of new treatments and often cannot be replaced by active-control trials showing that a new drug is equivalent or noninferior to a known effective agent. The limitations of active-control equivalence trials (ACETs) that are intended to show the effectiveness of a new drug have long been recognized and are well described (15-33) but are perhaps not as widely appreciated as they should be. A recent proposed international guideline on choice of control group addresses this issue in detail (33). The Fundamental Problem: Need for Assay Sensitivity There are two distinct ways to show that a new therapy is effective. One can show that the new therapy is superior to a control treatment, or one can show that the new therapy is equivalent to or not worse by some defined amount than a known effective treatment. Each method can be valid, but each requires entirely different inferential approaches. A well-designed study that shows superiority of a treatment to a control (placebo or active therapy) provides strong evidence of the effectiveness of the new treatment, limited only by the statistical uncertainty of the result. No information external to the trial is needed to support the conclusion of effectiveness. In contrast, a study that successfully shows equivalencethat is, little difference between a new drug and known active treatmentdoes not by itself demonstrate that the new treatment is effective. Equivalence could mean that the treatments were both effective in the study, but it could also mean that both treatments were ineffective in the study. To conclude from an ACET that a new treatment is effective on the basis of its similarity to the active control, one must make the critical (and untestable within the study) assumption that the active control had an effect in that particular study. In other words, one must assume that if a placebo group had been included, the placebo would have been inferior to the active control (15-33). Support for this assumption must come from sources external to the trial. Although it might appear reasonable to expect a known active agent to be superior to placebo in any given appropriately designed trial, experience has shown that this is not the case for many types of drugs. The ability of a study to distinguish between active and inactive treatments is termed assay sensitivity. If assay sensitivity cannot be assumed, then even if the new and standard treatments appear virtually identical and the confidence interval for their comparison is exquisitely narrow, the study cannot demonstrate effectiveness of the new drug. (Note that in practice, ACETs are not designed simply to show lack of a statistically significant difference between treatments. Rather, such trials are designed to show noninferioritythat the new treatment is not inferior to the control by more than a specified margin. This approach is described in the Appendix.) The best evidence that an active drug would have an effect superior to that of placebo in a given study would be a series of trials of similar design in which the active drug has reliably outperformed placebo. The ACET thus requires information external to the trial (the information about past placebo-controlled studies of the active control) to interpret the results. In this respect, an ACET is similar to a historically controlled trial. In some settings, such as highly responsive cancers, most infectious diseases, and some cardiovascular conditions, such external information is available and ACETs can and do provide a valid and reliable basis for evaluating new treatments. In many cases, however, the historically based assumption of assay sensitivity cannot be made; for many types of effective drugs, studies of apparently adequate size and design do not regularly distinguish drugs from placebo (16-18, 25, 34). More than 20 years ago, Lasagna (19) described this difficulty particularly well (reflecting long recognition of the problem among analgesiologists): a comparison between new drug and standard is convincing only when the new remedy is superior to standard treatment. If it is inferior, or even indistinguishable from a standard remedy, the results are not readily interpretable. In the absence of placebo controls, one does not know if the inferior new medicine has any efficacy at all, and equivalent performance may reflect simply a patient population that cannot distinguish between two active treatments that differ considerably from each other, or between active drug and placebo. Certain clinical conditions, such as seri", "title": "Placebo-Controlled Trials and Active-Control Trials in the Evaluation of New Treatments. Part 1: Ethical and Scientific Issues" }, { "docid": "13843341", "text": "OBJECTIVE To evaluate the cost effectiveness of standard treatment with and without the addition of ward based non-invasive ventilation in patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease. \n DESIGN Incremental cost effectiveness analysis of a randomised controlled trial. \n SETTING Medical wards in 14 hospitals in the United Kingdom. \n PARTICIPANTS The trial comprised 236 patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease and mild to moderate acidosis (pH 7.25-7.35) secondary to respiratory failure. The economic analysis compared the costs of treatment that these patients received after randomisation. \n MAIN OUTCOME MEASURE Incremental cost per in-hospital death. \n RESULTS 24/118 died in the group receiving standard treatment and 12/118 in the group receiving non-invasive ventilation (P=0.05). Allocation to the group receiving non-invasive ventilation was associated with a reduction in costs of 49362 pounds sterling (78741 dollars; 73109 euros), mainly through reduced use of intensive care units. The incremental cost effectiveness ratio was -645 pounds sterling per death avoided (95% confidence interval -2310 pounds sterling to 386 pounds sterling), indicating a dominant (more effective and less costly) strategy. Modelling of these data indicates that a typical UK hospital providing a non-invasive ventilation service will avoid six deaths and three to nine admissions to intensive care units per year, with an associated cost reduction of 12000-53000 pounds sterling per year. \n CONCLUSIONS Non-invasive ventilation is a highly cost effective treatment that both reduced total costs and improved mortality in hospital.", "title": "Cost effectiveness of ward based non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease: economic analysis of randomised controlled trial." }, { "docid": "13625993", "text": "OBJECTIVE To determine the effectiveness and cost effectiveness of using information from circulating biomarkers to inform the prioritisation process of patients with stable angina awaiting coronary artery bypass graft surgery. \n DESIGN Decision analytical model comparing four prioritisation strategies without biomarkers (no formal prioritisation, two urgency scores, and a risk score) and three strategies based on a risk score using biomarkers: a routinely assessed biomarker (estimated glomerular filtration rate), a novel biomarker (C reactive protein), or both. The order in which to perform coronary artery bypass grafting in a cohort of patients was determined by each prioritisation strategy, and mean lifetime costs and quality adjusted life years (QALYs) were compared. \n DATA SOURCES Swedish Coronary Angiography and Angioplasty Registry (9935 patients with stable angina awaiting coronary artery bypass grafting and then followed up for cardiovascular events after the procedure for 3.8 years), and meta-analyses of prognostic effects (relative risks) of biomarkers. \n RESULTS The observed risk of cardiovascular events while on the waiting list for coronary artery bypass grafting was 3 per 10,000 patients per day within the first 90 days (184 events in 9935 patients). Using a cost effectiveness threshold of pound20,000- pound30,000 (euro22,000-euro33,000; $32,000-$48,000) per additional QALY, a prioritisation strategy using a risk score with estimated glomerular filtration rate was the most cost effective strategy (cost per additional QALY was < pound410 compared with the Ontario urgency score). The impact on population health of implementing this strategy was 800 QALYs per 100,000 patients at an additional cost of pound 245,000 to the National Health Service. The prioritisation strategy using a risk score with C reactive protein was associated with lower QALYs and higher costs compared with a risk score using estimated glomerular filtration rate. \n CONCLUSION Evaluating the cost effectiveness of prognostic biomarkers is important even when effects at an individual level are small. Formal prioritisation of patients awaiting coronary artery bypass grafting using a routinely assessed biomarker (estimated glomerular filtration rate) along with simple, routinely collected clinical information was cost effective. Prioritisation strategies based on the prognostic information conferred by C reactive protein, which is not currently measured in this context, or a combination of C reactive protein and estimated glomerular filtration rate, is unlikely to be cost effective. The widespread practice of using only implicit or informal means of clinically ordering the waiting list may be harmful and should be replaced with formal prioritisation approaches.", "title": "Assessing the cost effectiveness of using prognostic biomarkers with decision models: case study in prioritising patients waiting for coronary artery surgery" }, { "docid": "583260", "text": "Adverse drug events (ADEs) are the harms associated with uses of given medications at normal dosages, which are crucial for a drug to be approved in clinical use or continue to stay on the market. Many ADEs are not identified in trials until the drug is approved for clinical use, which results in adverse morbidity and mortality. To date, millions of ADEs have been reported around the world. Methods to avoid or reduce ADEs are an important issue for drug discovery and development. Here, we reported a comprehensive database of adverse drug events (namely MetaADEDB), which included more than 520,000 drug-ADE associations among 3059 unique compounds (including 1330 drugs) and 13,200 ADE items by data integration and text mining. All compounds and ADEs were annotated with the most commonly used concepts defined in Medical Subject Headings (MeSH). Meanwhile, a computational method, namely the phenotypic network inference model (PNIM), was developed for prediction of potential ADEs based on the database. The area under the receive operating characteristic curve (AUC) is more than 0.9 by 10-fold cross validation, while the AUC value was 0.912 for an external validation set extracted from the US-FDA Adverse Events Reporting System, which indicated that the prediction capability of the method was reliable. MetaADEDB is accessible free of charge at http://www.lmmd.org/online_services/metaadedb/. The database and the method provide us a useful tool to search for known side effects or predict potential side effects for a given drug or compound.", "title": "Adverse drug events: database construction and in silico prediction." }, { "docid": "13071728", "text": "BACKGROUND The World Health Organization (WHO) released revised guidelines in 2015 recommending that all people living with HIV, regardless of CD4 count, initiate antiretroviral therapy (ART) upon diagnosis. However, few studies have projected the global resources needed for rapid scale-up of ART. Under the Health Policy Project, we conducted modeling analyses for 97 countries to estimate eligibility for and numbers on ART from 2015 to 2020, along with the facility-level financial resources required. We compared the estimated financial requirements to estimated funding available. \n METHODS AND FINDINGS Current coverage levels and future need for treatment were based on country-specific epidemiological and demographic data. Simulated annual numbers of individuals on treatment were derived from three scenarios: (1) continuation of countries' current policies of eligibility for ART, (2) universal adoption of aspects of the WHO 2013 eligibility guidelines, and (3) expanded eligibility as per the WHO 2015 guidelines and meeting the Joint United Nations Programme on HIV/AIDS \"90-90-90\" ART targets. We modeled uncertainty in the annual resource requirements for antiretroviral drugs, laboratory tests, and facility-level personnel and overhead. We estimate that 25.7 (95% CI 25.5, 26.0) million adults and 1.57 (95% CI 1.55, 1.60) million children could receive ART by 2020 if countries maintain current eligibility plans and increase coverage based on historical rates, which may be ambitious. If countries uniformly adopt aspects of the WHO 2013 guidelines, 26.5 (95% CI 26.0 27.0) million adults and 1.53 (95% CI 1.52, 1.55) million children could be on ART by 2020. Under the 90-90-90 scenario, 30.4 (95% CI 30.1, 30.7) million adults and 1.68 (95% CI 1.63, 1.73) million children could receive treatment by 2020. The facility-level financial resources needed for scaling up ART in these countries from 2015 to 2020 are estimated to be US$45.8 (95% CI 45.4, 46.2) billion under the current scenario, US$48.7 (95% CI 47.8, 49.6) billion under the WHO 2013 scenario, and US$52.5 (95% CI 51.4, 53.6) billion under the 90-90-90 scenario. After projecting recent external and domestic funding trends, the estimated 6-y financing gap ranges from US$19.8 billion to US$25.0 billion, depending on the costing scenario and the U.S. President's Emergency Plan for AIDS Relief contribution level, with the gap for ART commodities alone ranging from US$14.0 to US$16.8 billion. The study is limited by excluding above-facility and other costs essential to ART service delivery and by the availability and quality of country- and region-specific data. \n CONCLUSIONS The projected number of people receiving ART across three scenarios suggests that countries are unlikely to meet the 90-90-90 treatment target (81% of people living with HIV on ART by 2020) unless they adopt a test-and-offer approach and increase ART coverage. Our results suggest that future resource needs for ART scale-up are smaller than stated elsewhere but still significantly threaten the sustainability of the global HIV response without additional resource mobilization from domestic or innovative financing sources or efficiency gains. As the world moves towards adopting the WHO 2015 guidelines, advances in technology, including the introduction of lower-cost, highly effective antiretroviral regimens, whose value are assessed here, may prove to be \"game changers\" that allow more people to be on ART with the resources available.", "title": "The HIV Treatment Gap: Estimates of the Financial Resources Needed versus Available for Scale-Up of Antiretroviral Therapy in 97 Countries from 2015 to 2020" }, { "docid": "16812091", "text": "CONTEXT Osteoporosis causes substantial morbidity and costs $13.8 billion annually in the United States. Measurement of bone mass by densitometry is a primary part of diagnosing osteoporosis and deciding a preventive treatment course. Bone mineral densitometry has become more widely available and commonly used in practice. \n OBJECTIVE To review evidence about the value of various clinical applications of bone densitometry. \n DATA SOURCES A MEDLINE search was performed to update previous meta-analyses of the relationship between various measurements of bone density and risk of vertebral and hip fracture. We used data from the prospective Study of Osteoporotic Fractures to estimate risk of fracture from bone density and age in postmenopausal women. STUDY SELECTION AND DATA EXTRACTION When available, meta-analyses and systematic reviews are emphasized in the review. \n DATA SYNTHESIS Bone mineral density (BMD) predicts fracture and can be used in combination with age to estimate absolute risk of fractures in postmenopausal white women. Hip BMD predicts hip fracture more strongly than other measurements of BMD. There are insufficient data to translate BMD results into risk of fracture for men and nonwhite women. The benefits of treatments to prevent fractures depend on BMD: women with osteoporosis have a greater risk of fractures and greater benefit from treatments than women without osteoporosis. \n CONCLUSIONS Guidelines based on systematic reviews and a cost-effectiveness analysis have suggested that it is worthwhile to measure BMD in white women older than 65 years and perhaps to use risk factors to select younger postmenopausal women for densitometry. Other potential clinical applications of BMD that have not yet been adequately studied include screening men or nonwhite women, monitoring BMD in patients receiving treatment, and using BMD to identify patients who should be evaluated for secondary causes of osteoporosis.", "title": "Clinical use of bone densitometry: scientific review." }, { "docid": "1287809", "text": "IMPORTANCE The American College of Cardiology and the American Heart Association (ACC/AHA) cholesterol treatment guidelines have wide-scale implications for treating adults without history of atherosclerotic cardiovascular disease (ASCVD) with statins. \n OBJECTIVE To estimate the cost-effectiveness of various 10-year ASCVD risk thresholds that could be used in the ACC/AHA cholesterol treatment guidelines. \n DESIGN, SETTING, AND PARTICIPANTS Microsimulation model, including lifetime time horizon, US societal perspective, 3% discount rate for costs, and health outcomes. In the model, hypothetical individuals from a representative US population aged 40 to 75 years received statin treatment, experienced ASCVD events, and died from ASCVD-related or non-ASCVD-related causes based on ASCVD natural history and statin treatment parameters. Data sources for model parameters included National Health and Nutrition Examination Surveys, large clinical trials and meta-analyses for statin benefits and treatment, and other published sources. \n MAIN OUTCOMES AND MEASURES Estimated ASCVD events prevented and incremental costs per quality-adjusted life-year (QALY) gained. \n RESULTS In the base-case scenario, the current ASCVD threshold of 7.5% or higher, which was estimated to be associated with 48% of adults treated with statins, had an incremental cost-effectiveness ratio (ICER) of $37,000/QALY compared with a 10% or higher threshold. More lenient ASCVD thresholds of 4.0% or higher (61% of adults treated) and 3.0% or higher (67% of adults treated) had ICERs of $81,000/QALY and $140,000/QALY, respectively. Shifting from a 7.5% or higher ASCVD risk threshold to a 3.0% or higher ASCVD risk threshold was estimated to be associated with an additional 161,560 cardiovascular disease events averted. Cost-effectiveness results were sensitive to changes in the disutility associated with taking a pill daily, statin price, and the risk of statin-induced diabetes. In probabilistic sensitivity analysis, there was a higher than 93% chance that the optimal ASCVD threshold was 5.0% or lower using a cost-effectiveness threshold of $100,000/QALY. \n CONCLUSIONS AND RELEVANCE In this microsimulation model of US adults aged 45 to 75 years [corrected], the current 10-year ASCVD risk threshold (≥7.5% risk threshold) used in the ACC/AHA cholesterol treatment guidelines has an acceptable cost-effectiveness profile (ICER, $37,000/QALY), but more lenient ASCVD thresholds would be optimal using cost-effectiveness thresholds of $100,000/QALY (≥4.0% risk threshold) or $150,000/QALY (≥3.0% risk threshold). The optimal ASCVD threshold was sensitive to patient preferences for taking a pill daily, changes to statin price, and the risk of statin-induced diabetes.", "title": "Cost-effectiveness of 10-Year Risk Thresholds for Initiation of Statin Therapy for Primary Prevention of Cardiovascular Disease." }, { "docid": "6748318", "text": "BACKGROUND In Spain, prophylactic vaccination against human papillomavirus (HPV) types 16 and 18 is being offered free-of-charge to one birth cohort of girls aged 11-14. Screening is opportunistic (annual/biannual) contributing to social and geographical disparities. \n METHODS A multi-HPV-type microsimulation model was calibrated to epidemiologic data from Spain utilising likelihood-based methods to assess the health and economic impact of adding HPV vaccination to cervical cancer screening. Strategies included (1) screening alone of women over age 25, varying frequency (every 1-5 years) and test (cytology, HPV DNA testing); (2) HPV vaccination of 11-year-old girls combined with screening. Outcomes included lifetime cancer risk, life expectancy, lifetime costs, number of clinical procedures and incremental cost-effectiveness ratios. \n RESULTS After the introduction of HPV vaccination, screening will need to continue, and strategies that incorporated HPV testing are more effective and cost-effective than those with cytology alone. For vaccinated girls, 5-year organised cytology with HPV testing as triage from ages 30 to 65 costs 24,350€ per year of life saved (YLS), assuming life-long vaccine immunity against HPV-16/18 by 3 doses with 90% coverage. Unvaccinated girls would benefit from organised cytology screening with HPV testing as triage; 5-year screening from ages 30 to 65 costs 16,060€/YLS and 4-year screening from ages 30 to 85 costs 38,250€/YLS. Interventions would be cost-effective depending on the cost-effectiveness threshold and the vaccine price. \n CONCLUSIONS In Spain, inequitable coverage and overuse of cytology make screening programmes inefficient. If high vaccination coverage among pre-adolescent girls is achieved, organised cytology screening with HPV triage starting at ages 30 to at least 65 every 4-5 years represents the best balance between costs and benefits.", "title": "Cost-effectiveness of human papillomavirus vaccination and screening in Spain." }, { "docid": "21203899", "text": "Kidney donor exchanges enable recipients with immunologically incompatible donors to receive compatible living donor grafts; however, the financial management of these exchanges, especially when an organ is shipped, is complex and thus has the potential to impede the broader implementation of donor exchange programs. Representatives from transplant centers that utilize the National Kidney Registry database to facilitate donor exchange transplants developed a financial model applicable to paired donor exchanges and donor chain transplants. The first tenet of the model is to eliminate financial liability to the donor. Thereafter, it accounts for the donor evaluation, donor nephrectomy hospital costs, donor nephrectomy physician fees, organ transport, donor complications and recipient inpatient services. Billing between hospitals is based on Medicare cost report defined costs rather than charges. We believe that this model complies with current federal regulations and effectively captures costs of the donor and recipient services. It could be considered as a financial paradigm for the United Network for Organ Sharing managed donor exchange program.", "title": "Managing finances of shipping living donor kidneys for donor exchanges." }, { "docid": "25499612", "text": "Despite its key role in determining the stability and intensity of malaria transmission, the infectiousness of human populations to mosquitoes has rarely been estimated. Field-based analyses of malaria transmission have frequently relied on the prevalence of asexual parasites or gametocytes as proxies for infectiousness. We now summarize empirical data on human infectiousness from Africa and Papua New Guinea. Over a wide range of transmission intensities there is little relationship between the infectiousness of human populations to vector mosquitoes and mosquito-to-human transmission intensity. We compare these data with the predictions of a stochastic simulation model of Plasmodium falciparum epidemiology. This model predicted little variation in the infectiousness of the human population for entomologic inoculation rates (EIRs) greater than approximately 10 infectious bites per year, demonstrating that the lack of relationship between the EIR and the infectious reservoir can be explained without invoking any effects of acquired transmission-blocking immunity. The near absence of field data from areas with an EIR < 10 per year precluded validation of the model predictions for low EIR values. These results suggest that interventions reducing mosquito-to-human transmission will have little or no effect on human infectiousness at the levels of transmission found in most rural areas of sub-Saharan Africa. Unless very large reductions in transmission can be achieved, measures to prevent mosquito-to-human transmission need to be complemented with interventions that reduce the density or infectiousness of blood stage parasites.", "title": "Infectiousness of malaria-endemic human populations to vectors." }, { "docid": "12470783", "text": "PURPOSE There is a need for valid and reliable short scales that can be used to assess social networks and social supports and to screen for social isolation in older persons. \n DESIGN AND METHODS The present study is a cross-national and cross-cultural evaluation of the performance of an abbreviated version of the Lubben Social Network Scale (LSNS-6), which was used to screen for social isolation among community-dwelling older adult populations in three European countries. Based on the concept of lack of redundancy of social ties we defined clinical cut-points of the LSNS-6 for identifying persons deemed at risk for social isolation. \n RESULTS Among all three samples, the LSNS-6 and two subscales (Family and Friends) demonstrated high levels of internal consistency, stable factor structures, and high correlations with criterion variables. The proposed clinical cut-points showed good convergent validity, and classified 20% of the respondents in Hamburg, 11% of those in Solothurn (Switzerland), and 15% of those in London as at risk for social isolation. IMPLICATIONS We conclude that abbreviated scales such as the LSNS-6 should be considered for inclusion in practice protocols of gerontological practitioners. Screening older persons based on the LSNS-6 provides quantitative information on their family and friendship ties, and identifies persons at increased risk for social isolation who might benefit from in-depth assessment and targeted interventions.", "title": "Performance of an abbreviated version of the Lubben Social Network Scale among three European community-dwelling older adult populations." }, { "docid": "25049067", "text": "OBJECTIVE To conduct an economic analysis of the Hlabisa community-based directly observed therapy management strategy for tuberculosis and to project costs of three alternative strategies. \n SETTING Hlabisa health district, KwaZulu-Natal, South Africa. \n METHODS An economic analysis comparing the current tuberculosis management strategy in Hlabisa with three alternative strategies (the Hlabisa strategy prior to 1991 based on hospitalisation, the national strategy and sanatorium care) in terms of costs to both health service and patient and of cost-effectiveness. \n RESULTS The current Hlabisa strategy was the most cost-effective (R3799 per patient cured), compared with R98307 for the strategy used prior to 1991, R9940 for the national strategy, and R11145 for sanatorium care. Between 71% and 88% of treatment costs lie with the health service, and hospitalisation (R119 per day) is the most expensive item. Prolonged hospitalisation is extremely expensive, but community care is cheaper (community clinic visit, R28; community health worker visit, R7). The total cost of supervising a patient in the community under the current Hlabisa strategy was R503, equivalent to 4.2 days in hospital. Drug costs (R157) are equivalent to just 1.3 days in hospital. \n CONCLUSION Cost to both health service and patient can be substantially reduced by using community-based directly observed therapy for tuberculosis, a strategy that is cheap and cost-effective in Hlabisa. These findings have important national implications, supporting the goals of the new tuberculosis control programme.", "title": "Costs and cost-effectiveness of alternative tuberculosis management strategies in South Africa--implications for policy." }, { "docid": "95102458", "text": "Abstract Several processes for the production and recovery of poly(3-hydroxybutyrate) (PHB) by Alcaligenes eutrophus, Alcaligenes latus, Methylobacterium organophilum, and recombinant Escherichia coli were designed based on the previously reported data and analyzed by computer-aided bioprocess design. PHB productivity, content, and yield significantly affected the final price of PHB. For the annual production of 2,850 tonnes of purified PHB, the process employing A. eutrophus with the recovery method of surfactant-hypochlorite digestion resulted in lowest price of PHB, $ 5.58/kg. As the production scale increased to one million tonnes per year, the price of PHB dropped to $ 4.75/kg. The cost of carbon substrate significantly affected the overall economics in large production scale. Therefore, the production cost can be considerably lowered when agricultural wastes, such as whey and molasses, are used.", "title": "Process analysis and economic evaluation for Poly(3-hydroxybutyrate) production by fermentation" }, { "docid": "22467585", "text": "Background: The loss of a child during pregnancy causes significant psychological distress for many women and their partners, and may lead to long-lasting psychiatric disorders. Internet-based interventions using exposure techniques and cognitive restructuring have proved effective for posttraumatic stress disorder (PTSD) and prolonged grief. This study compared the effects of an Internet-based intervention for parents after prenatal loss with a waiting list condition (WLC). Methods: The Impact of Event Scale - Revised assessed symptoms of PTSD; the Inventory of Complicated Grief and the Brief Symptom Inventory assessed depression, anxiety, and general mental health. The 228 participants (92% female) were randomly allocated to a treatment group (TG; n = 115) or a WLC group (n = 113). The TG received a 5-week cognitive behavioral intervention including (1) self-confrontation, (2) cognitive restructuring, and (3) social sharing. Results: The TG showed significantly reduced symptoms of posttraumatic stress, prolonged grief, depression, and anxiety relative to the WLC control group. Intention-to-treat analysis revealed treatment effects of between d = 0.84 and d = 1.02 for posttraumatic stress and prolonged grief from pre- to posttreatment time points. Further significant improvement in all symptoms of PTSD and prolonged grief was found from the posttreatment evaluation to the 12-month follow-up. The attrition rate of 14% was relatively low. Conclusions: The Internet-based intervention proved to be a feasible and cost-effective treatment, reducing symptoms of posttraumatic stress, grief, depression, anxiety, and general mental health after pregnancy loss. Low-threshold e-health interventions should be further evaluated and implemented routinely to improve psychological support after pregnancy loss.", "title": "Brief Internet-Based Intervention Reduces Posttraumatic Stress and Prolonged Grief in Parents after the Loss of a Child during Pregnancy: A Randomized Controlled Trial" }, { "docid": "38180456", "text": "Short-term medical service trips (MSTs) aim to address unmet health care needs of low- and middle-income countries. The lack of critically reviewed empirical evidence of activities and outcomes is a concern. Developing evidence-based recommendations for health care delivery requires systematic research review. I focused on MST publications with empirical results. Searches in May 2013 identified 67 studies published since 1993, only 6% of the published articles on the topic in the past 20 years. Nearly 80% reported on surgical trips. Although the MST field is growing, its medical literature lags behind, with nearly all of the scholarly publications lacking significant data collection. By incorporating data collection into service trips, groups can validate practices and provide information about areas needing improvement.", "title": "Short-term medical service trips: a systematic review of the evidence." }, { "docid": "5151024", "text": "BACKGROUND The diagnosis of hypertension has traditionally been based on blood-pressure measurements in the clinic, but home and ambulatory measurements better correlate with cardiovascular outcome, and ambulatory monitoring is more accurate than both clinic and home monitoring in diagnosing hypertension. We aimed to compare the cost-effectiveness of different diagnostic strategies for hypertension. \n METHODS We did a Markov model-based probabilistic cost-effectiveness analysis. We used a hypothetical primary-care population aged 40 years or older with a screening blood-pressure measurement greater than 140/90 mm Hg and risk-factor prevalence equivalent to the general population. We compared three diagnostic strategies-further blood pressure measurement in the clinic, at home, and with an ambulatory monitor-in terms of lifetime costs, quality-adjusted life years, and cost-effectiveness. \n FINDINGS Ambulatory monitoring was the most cost-effective strategy for the diagnosis of hypertension for men and women of all ages. It was cost-saving for all groups (from -£56 [95% CI -105 to -10] in men aged 75 years to -£323 [-389 to -222] in women aged 40 years) and resulted in more quality-adjusted life years for men and women older than 50 years (from 0·006 [0·000 to 0·015] for women aged 60 years to 0·022 [0·012 to 0·035] for men aged 70 years). This finding was robust when assessed with a wide range of deterministic sensitivity analyses around the base case, but was sensitive if home monitoring was judged to have equal test performance to ambulatory monitoring or if treatment was judged effective irrespective of whether an individual was hypertensive. \n INTERPRETATION Ambulatory monitoring as a diagnostic strategy for hypertension after an initial raised reading in the clinic would reduce misdiagnosis and save costs. Additional costs from ambulatory monitoring are counterbalanced by cost savings from better targeted treatment. Ambulatory monitoring is recommended for most patients before the start of antihypertensive drugs. \n FUNDING National Institute for Health Research and the National Institute for Health and Clinical Excellence.", "title": "Cost-effectiveness of options for the diagnosis of high blood pressure in primary care: a modelling study." }, { "docid": "15670968", "text": "Many countries use the cost-effectiveness thresholds recommended by the World Health Organization's Choosing Interventions that are Cost-Effective project (WHO-CHOICE) when evaluating health interventions. This project sets the threshold for cost-effectiveness as the cost of the intervention per disability-adjusted life-year (DALY) averted less than three times the country's annual gross domestic product (GDP) per capita. Highly cost-effective interventions are defined as meeting a threshold per DALY averted of once the annual GDP per capita. We argue that reliance on these thresholds reduces the value of cost-effectiveness analyses and makes such analyses too blunt to be useful for most decision-making in the field of public health. Use of these thresholds has little theoretical justification, skirts the difficult but necessary ranking of the relative values of locally-applicable interventions and omits any consideration of what is truly affordable. The WHO-CHOICE thresholds set such a low bar for cost-effectiveness that very few interventions with evidence of efficacy can be ruled out. The thresholds have little value in assessing the trade-offs that decision-makers must confront. We present alternative approaches for applying cost-effectiveness criteria to choices in the allocation of health-care resources.", "title": "Thresholds for the cost–effectiveness of interventions: alternative approaches" }, { "docid": "97566194", "text": "Abstract Within some data limitations, the paper provides a first assessment of areas in Australia with potential for implementing desalination technologies to supply agricultural water. At the national scale, these areas were identified based on a set of selected criteria: distance from land currently used for irrigated agriculture and feedlots; distance from town sites; exclusion of areas of environmental protection; exclusion of areas with surface elevation greater than 600 m AHD; and exclusion of regions with limited groundwater resources. Industries involved in the production of high-value crops are most likely to benefit from desalinated water as they use more-efficient irrigation practices and have the highest gross value of irrigated agricultural production. Groundwater was identified as the most likely feedwater source for cost-effective desalination, which is also the case worldwide. Brine disposal is a major factor in overall cost effectiveness of desalination. When feedwater salinity is relatively low, mixing permeate with feedwater leads to an increase in water production and a reduction in water cost. It was estimated that Australian farmers are unlikely to pay more than AU$1.2/kL for agricultural water. Generally for agriculture, desalinated water is still more expensive than water from other sources; however, there are likely to be circumstances when the costs could be comparable.", "title": "Feasibility assessment of desalination application in Australian traditional agriculture" } ]

[ { "docid": "10874408", "text": "DNA double-strand breaks (DSBs), which are formed by the Spo11 protein, initiate meiotic recombination. Previous DSB-mapping studies have used rad50S or sae2Δ mutants, which are defective in break processing, to accumulate Spo11-linked DSBs, and report large (≥ 50 kb) “DSB-hot” regions that are separated by “DSB-cold” domains of similar size. Substantial recombination occurs in some DSB-cold regions, suggesting that DSB patterns are not normal in rad50S or sae2Δ mutants. We therefore developed a novel method to map genome-wide, single-strand DNA (ssDNA)–associated DSBs that accumulate in processing-capable, repair-defective dmc1Δ and dmc1Δ rad51Δ mutants. DSBs were observed at known hot spots, but also in most previously identified “DSB-cold” regions, including near centromeres and telomeres. Although approximately 40% of the genome is DSB-cold in rad50S mutants, analysis of meiotic ssDNA from dmc1Δ shows that most of these regions have substantial DSB activity. Southern blot assays of DSBs in selected regions in dmc1Δ, rad50S, and wild-type cells confirm these findings. Thus, DSBs are distributed much more uniformly than was previously believed. Comparisons of DSB signals in dmc1, dmc1 rad51, and dmc1 spo11 mutant strains identify Dmc1 as a critical strand-exchange activity genome-wide, and confirm previous conclusions that Spo11-induced lesions initiate all meiotic recombination.", "title": "Mapping Meiotic Single-Strand DNA Reveals a New Landscape of DNA Double-Strand Breaks in Saccharomyces cerevisiae" } ]

[ { "docid": "21170174", "text": "During meiosis, recombination between homologous chromosomes generates crossover (CR) and noncrossover (NCR) products. CRs establish connections between homologs, whereas intermediates leading to NCRs have been proposed to participate in homologous pairing. How these events are differentiated and regulated remains to be determined. We have developed a strategy to detect, quantify, and map NCRs in parallel to CRs, at the Psmb9 meiotic recombination hot spot, in male and female mouse germ lines. Our results report direct molecular evidence for distinct CR and NCR pathways of DNA double-strand break (DSB) repair in mouse meiosis based on three observations: both CRs and NCRs require Spo11, NCR products have shorter conversion tracts than CRs, and only CRs require the MutL homolog Mlh1. We show that both products are formed from middle to late pachytene of meiotic prophase and provide evidence for an Mlh1-independent CR pathway, where mismatch repair does not require Mlh1.", "title": "Crossover and noncrossover pathways in mouse meiosis." }, { "docid": "42267740", "text": "Various proteins have been found to play roles in both the repair of UV damaged DNA and heterochromatin-mediated silencing in the yeast Saccharomyces cerevisiae. In particular, factors that are involved in the methylation of lysine-79 of histone H3 by Dot1p have been implicated in both processes, suggesting a bipartite function for this modification. We find that a dot1 null mutation and a histone H3 point mutation at lysine-79 cause increased sensitivity to UV radiation, suggesting that lysine-79 methylation is important for efficient repair of UV damage. Epistasis analysis between dot1 and various UV repair genes indicates that lysine-79 methylation plays overlapping roles within the nucleotide excision, post-replication and recombination repair pathways, as well as RAD9-mediated checkpoint function. In contrast, epistasis analysis with the H3 lysine-79 point mutation indicates that the lysine-to-glutamic acid substitution exerts specific effects within the nucleotide excision repair and post-replication repair pathways, suggesting that this allele only disrupts a subset of the functions of lysine-79 methylation. The overall results indicate the existence of distinct and separable roles of histone H3 lysine-79 methylation in the response to UV damage, potentially serving to coordinate the various repair processes.", "title": "Methylation of histone H3 lysine-79 by Dot1p plays multiple roles in the response to UV damage in Saccharomyces cerevisiae." }, { "docid": "16237005", "text": "Proper execution of transcriptional programs is a key requirement of gene expression regulation, demanding accurate control of timing and amplitude. How precisely the transcription machinery fulfills this task is not known. Using an in situ hybridization approach that detects single mRNA molecules, we measured mRNA abundance and transcriptional activity within single Saccharomyces cerevisiae cells. We found that expression levels for particular genes are higher than initially reported and can vary substantially among cells. However, variability for most constitutively expressed genes is unexpectedly small. Combining single-transcript measurements with computational modeling indicates that low expression variation is achieved by transcribing genes using single transcription-initiation events that are clearly separated in time, rather than by transcriptional bursts. In contrast, PDR5, a gene regulated by the transcription coactivator complex SAGA, is expressed using transcription bursts, resulting in larger variation. These data directly demonstrate the existence of multiple expression modes used to modulate the transcriptome.", "title": "Single-RNA counting reveals alternative modes of gene expression in yeast" }, { "docid": "23604601", "text": "The IME1 gene of Saccharomyces cerevisiae is required for initiation of meiosis. Transcription of IME1 is detected under conditions which are known to induce initiation of meiosis, namely starvation for nitrogen and glucose, and the presence of MATa1 and MAT alpha 2 gene products. In this paper we show that IME1 is also subject to translational regulation. Translation of IME1 mRNA is achieved either upon nitrogen starvation, or upon G1 arrest. In the presence of nutrients, constitutively elevated transcription of IME1 is also sufficient for the translation of IME1 RNA. Four different conditions were found to cause expression of Ime1 protein in vegetative cultures: elevated transcription levels due to the presence of IME1 on a multicopy plasmid; elevated transcription provided by a Gal-IME1 construct; G1 arrest due to alpha-factor treatment; G1 arrest following mild heat-shock treatment of cdc28 diploids. Using these conditions, we obtained evidence that starvation is required not only for transcription and efficient translation of IME1, but also for either the activation of Ime1 protein or for the induction/activation of another factor that, either alone or in combination with Ime1, induces meiosis.", "title": "Post-transcriptional regulation of IME1 determines initiation of meiosis in Saccharomyces cerevisiae." }, { "docid": "365896", "text": "We describe methods for obtaining a quantitative description of RNA processing at high resolution in budding yeast. As a model gene expression system, we constructed tetON (for induction studies) and tetOFF (for repression, derepression, and RNA degradation studies) yeast strains with a series of reporter genes integrated in the genome under the control of a tetO7 promoter. Reverse transcription and quantitative real-time-PCR (RT-qPCR) methods were adapted to allow the determination of mRNA abundance as the average number of copies per cell in a population. Fluorescence in situ hybridization (FISH) measurements of transcript numbers in individual cells validated the RT-qPCR approach for the average copy-number determination despite the broad distribution of transcript levels within a population of cells. In addition, RT-qPCR was used to distinguish the products of the different steps in splicing of the reporter transcripts, and methods were developed to map and quantify 3'-end cleavage and polyadenylation. This system permits pre-mRNA production, splicing, 3'-end maturation and degradation to be quantitatively monitored with unprecedented kinetic detail, suitable for mathematical modeling. Using this approach, we demonstrate that reporter transcripts are spliced prior to their 3'-end cleavage and polyadenylation, that is, cotranscriptionally.", "title": "RiboSys, a high-resolution, quantitative approach to measure the in vivo kinetics of pre-mRNA splicing and 3'-end processing in Saccharomyces cerevisiae." }, { "docid": "1256116", "text": "The YEAst Search for Transcriptional Regulators And Consensus Tracking (YEASTRACT) information system (http://www.yeastract.com) was developed to support the analysis of transcription regulatory associations in Saccharomyces cerevisiae. Last updated in June 2010, this database contains over 48,200 regulatory associations between transcription factors (TFs) and target genes, including 298 specific DNA-binding sites for 110 characterized TFs. All regulatory associations stored in the database were revisited and detailed information on the experimental evidences that sustain those associations was added and classified as direct or indirect evidences. The inclusion of this new data, gathered in response to the requests of YEASTRACT users, allows the user to restrict its queries to subsets of the data based on the existence or not of experimental evidences for the direct action of the TFs in the promoter region of their target genes. Another new feature of this release is the availability of all data through a machine readable web-service interface. Users are no longer restricted to the set of available queries made available through the existing web interface, and can use the web service interface to query, retrieve and exploit the YEASTRACT data using their own implementation of additional functionalities. The YEASTRACT information system is further complemented with several computational tools that facilitate the use of the curated data when answering a number of important biological questions. Since its first release in 2006, YEASTRACT has been extensively used by hundreds of researchers from all over the world. We expect that by making the new data and services available, the system will continue to be instrumental for yeast biologists and systems biology researchers.", "title": "YEASTRACT: providing a programmatic access to curated transcriptional regulatory associations in Saccharomyces cerevisiae through a web services interface" }, { "docid": "41403996", "text": "DNA double strand breaks (DSBs) can be rejoined directly by the nonhomologous end-joining (NHEJ) pathway of repair. Nucleases and polymerases are required to promote accurate NHEJ when the terminal bases of the DSB are damaged. The same enzymes also participate in imprecise rejoining and joining of incompatible ends, important mutagenic events. Previous work has shown that the Pol X family polymerase Pol4 is required for some but not all NHEJ events that require gap filling in Saccharomyces cerevisiae. Here, we systematically analyzed DSB end configurations and found that gaps on both strands and overhang polarity are the principal factors that determine whether a joint requires Pol4. DSBs with 3'-overhangs and a gap on each strand strongly depended on Pol4 for repair, DSBs with 5'-overhangs of the same sequence did not. Pol4 was not required when 3'-overhangs contained a gap on only one strand, however. Pol4 was equally required at 3'-overhangs of all lengths within the NHEJ-dependent range but was dispensable outside of this range, indicating that Pol4 is specific to NHEJ. Loss of Pol4 did not affect the rejoining of DSBs that utilized a recessed microhomology or DSBs bearing 5'-hydroxyls but no gap. Finally, mammalian Pol X polymerases were able to differentially complement a pol4 mutation depending on the joint structure, demonstrating that these polymerases can participate in yeast NHEJ but with distinct properties.", "title": "DNA joint dependence of pol X family polymerase action in nonhomologous end joining." }, { "docid": "14145440", "text": "BACKGROUND DNA replication and mitosis are triggered by activation of kinase complexes, each made up of a cyclin and a cyclin-dependent kinase (Cdk). It had seemed possible that the association of Cdks with different classes of cyclins specifies whether S phase (replication) or M phase (mitosis) will occur. The recent finding that individual B-type cyclins (encoded by the genes CLB1-CLB6) can have functions in both processes in the budding yeast Saccharomyces cerevisiae casts doubt on this notion. \n RESULTS S. cerevisiae strains lacking C1b1-C1b4 undergo DNA replication once but fail to enter mitosis. We have isolated mutations in two genes, SIM1 and SIM2 (SIM2 is identical to SEC72), which allow such cells to undergo an extra round of DNA replication without mitosis. The Clb5 kinase, which promotes S phase, remains active during the G2-phase arrest of cells of the parental strain, but its activity declines rapidly in sim mutants. Increased expression of the CLB5 gene prevents re-replication. Thus, a cyclin B-kinase that promotes DNA replication in G1-phase cells can prevent re-replication in G2-phase cells. Inactivation of C1b kinases by expression of the specific C1b-Cdk1 inhibitor p40SIC1 is sufficient to induce a prereplicative state at origins of replication in cells blocked in G2/M phase by nocodazole. Re-activation of C1b-Cdk1 kinases induces a second round of DNA replication. \n CONCLUSIONS We propose that S-phase-promoting cyclin B--Cdk complexes prevent re-replication during S, G2 and M phases by inhibiting the transition of replication origins to a pre-replicative state. This model can explain both why origins 'fire' only once per S phase and why S phase is dependent on completion of the preceding M phase.", "title": "S-phase-promoting cyclin-dependent kinases prevent re-replication by inhibiting the transition of replication origins to a pre-replicative state" }, { "docid": "11527822", "text": "The SIR genes are determinants of life span in yeast mother cells. Here we show that life span regulation by the Sir proteins is independent of their role in nonhomologous end joining. The short life span of a sir3 or sir4 mutant is due to the simultaneous expression of a and alpha mating-type information, which indirectly causes an increase in rDNA recombination and likely increases the production of extrachromosomal rDNA circles. The short life span of a sir2 mutant also reveals a direct failure to repress recombination generated by the Fob1p-mediated replication block in the rDNA. Sir2p is a limiting component in promoting yeast longevity, and increasing the gene dosage extends the life span in wild-type cells. A possible role of the conserved SIR2 in mammalian aging is discussed.", "title": "The SIR2/3/4 complex and SIR2 alone promote longevity in Saccharomyces cerevisiae by two different mechanisms. Genes Dev 13" }, { "docid": "42421723", "text": "The induced synthesis of galactokinase and the repressing effects of glucose on this synthesis have been investigated in whole yeast cells rendered permeable by treatment with dimethyl sulfoxide. It was found that the induction response of uninduced cells to galactose is clearly dependent on the nature of the carbon source upon which the culture was grown prior to exposure to galactose. Glucose-grown cells exhibited a long lag before induction, whereas lactate-grown cells exhibited induced synthesis within 8 min. A concentration of 0.5% galactose was found to be optimal for induction. The addition of glucose to yeast cultures growing on galactose resulted in a severe transient repression of synthesis which was followed by a resumed rate of synthesis characteristic of a weaker permanent catabolite repression. Neither 2-deoxygalactose nor fucose acted as gratuitous inducers of the pathway, nor did they serve as a substrates for galactokinase.", "title": "Induction of galactokinase in Saccharomyces cerevisiae: kinetics of induction and glucose effects." }, { "docid": "9704467", "text": "We developed the Yeast Gene Order Browser (YGOB; http://wolfe.gen.tcd.ie/ygob) to facilitate visual comparisons and computational analysis of synteny relationships in yeasts. The data presented in YGOB, currently covering seven species, are based on sets of homologous genes that have been intensively manually curated based on both sequence similarity and genomic context (synteny). We reconciled different laboratories' lists of paralogous Saccharomyces cerevisiae gene pairs formed by genome duplication (ohnologs), and present near-exhaustive lists of the ohnolog pairs retained in S. cerevisiae (551, including 22 previously unidentified), Saccharomyces castellii (599), and Candida glabrata (404).", "title": "in polyploid species" }, { "docid": "32638085", "text": "Histone acetylation and deacetylation in the yeast Saccharomyces cerevisiae occur by targeting acetyltransferase and deacetylase enzymes to gene promoters and, in an untargeted and global manner, by affecting most nucleosomes. Recently, new roles for histone acetylation have been uncovered, not only in transcription but also in DNA replication, repair and heterochromatin formation. Interestingly, specific acetylatable lysines can function as binding sites for regulatory factors. Moreover, histone deacetylation is not only repressive but can be required for gene activity.", "title": "Histone acetylation and deacetylation in yeast" }, { "docid": "16686383", "text": "The centromeric histone H3 variant (CenH3) is essential for chromosome segregation in eukaryotes. We identify posttranslational modifications of Saccharomyces cerevisiae CenH3, Cse4. Functional characterization of cse4 phosphorylation mutants shows growth and chromosome segregation defects when combined with kinetochore mutants okp1 and ame1. Using a phosphoserine-specific antibody, we show that the association of phosphorylated Cse4 with centromeres increases in response to defective microtubule attachment or reduced cohesion. We determine that evolutionarily conserved Ipl1/Aurora B contributes to phosphorylation of Cse4, as levels of phosphorylated Cse4 are reduced at centromeres in ipl1 strains in vivo, and in vitro assays show phosphorylation of Cse4 by Ipl1. Consistent with these results, we observe that a phosphomimetic cse4-4SD mutant suppresses the temperature-sensitive growth of ipl1-2 and Ipl1 substrate mutants dam1 spc34 and ndc80, which are defective for chromosome biorientation. Furthermore, cell biology approaches using a green fluorescent protein-labeled chromosome show that cse4-4SD suppresses chromosome segregation defects in dam1 spc34 strains. On the basis of these results, we propose that phosphorylation of Cse4 destabilizes defective kinetochores to promote biorientation and ensure faithful chromosome segregation. Taken together, our results provide a detailed analysis, in vivo and in vitro, of Cse4 phosphorylation and its role in promoting faithful chromosome segregation.", "title": "Phosphorylation of centromeric histone H3 variant regulates chromosome segregation in Saccharomyces cerevisiae" }, { "docid": "1754001", "text": "The sirtuins are a phylogenetically conserved family of NAD(+) -dependent protein deacetylases that consume one molecule of NAD(+) for every deacetylated lysine side chain. Their requirement for NAD(+) potentially makes them prone to regulation by fluctuations in NAD(+) or biosynthesis intermediates, thus linking them to cellular metabolism. The Sir2 protein from Saccharomyces cerevisiae is the founding sirtuin family member and has been well characterized as a histone deacetylase that functions in transcriptional silencing of heterochromatin domains and as a pro-longevity factor for replicative life span (RLS), defined as the number of times a mother cell divides (buds) before senescing. Deleting SIR2 shortens RLS, while increased gene dosage causes extension. Furthermore, Sir2 has been implicated in mediating the beneficial effects of caloric restriction (CR) on life span, not only in yeast, but also in higher eukaryotes. While this paradigm has had its share of disagreements and debate, it has also helped rapidly drive the aging research field forward. S. cerevisiae has four additional sirtuins, Hst1, Hst2, Hst3, and Hst4. This review discusses the function of Sir2 and the Hst homologs in replicative aging and chronological aging, and also addresses how the sirtuins are regulated in response to environmental stresses such as CR.", "title": "Yeast sirtuins and the regulation of aging." }, { "docid": "615047", "text": "In the past years, simple organisms such as yeasts and worms have contributed a great deal to aging research. Studies pioneered in Saccharomyces cerevisiae were useful to elucidate a significant number of molecular mechanisms underlying cellular aging and to discover novel longevity genes. Importantly, these genes proved many times to be conserved in multicellular eukaryotes. Consequently, such discovery approaches are being extended to other yeast models, such as Schizosaccharomyces pombe, Candida albicans, Kluyveromyces lactis, and Cryptococcus neoformans. In fission yeast, researchers have found links between asymmetrical cell division and nutrient signaling pathways with aging. In this review, we discuss the state of knowledge on the mechanisms controlling both replicative and chronological aging in S pombe and the other emergent yeast models.", "title": "Fission yeast and other yeasts as emergent models to unravel cellular aging in eukaryotes." }, { "docid": "23664875", "text": "Termination of replication forks at the natural termini of the rDNA of Saccharomyces cerevisiae is controlled in a sequence-specific and polar mode by the interaction of the Fob1p replication terminator protein with the tandem Ter sites located in the nontranscribed spacers. Here we show, by both 2D gel analyses and chromatin immunoprecipitations (ChIP), that there exists a second level of global control mediated by the intra-S-phase checkpoint protein complex of Tof1p and Csm3p that protect stalled forks at Ter sites against the activity of the Rrm3p helicase (\"sweepase\"). The sweepase tends to release arrested forks presumably by the transient displacement of the Ter-bound Fob1p. Consistent with this mechanism, very few replication forks were arrested at the natural replication termini in the absence of the two checkpoint proteins. In the absence of the Rrm3p helicase, there was a slight enhancement of fork arrest at the Ter sites. Simultaneous deletions of the TOF1 (or CSM3), and the RRM3 genes restored fork arrest by removing both the fork-releasing and fork-protection activities. Other genes such as MRC1, WSS1, and PSY2 that are also involved in the MRC1 checkpoint pathway were not involved in this global control. This observation suggests that Tof1p-Csm3p function differently from MRC1 and the other above-mentioned genes. This mechanism is not restricted to the natural Ter sites but was also observed at fork arrest caused by the meeting of a replication fork with transcription approaching from the opposite direction.", "title": "The Tof1p-Csm3p protein complex counteracts the Rrm3p helicase to control replication termination of Saccharomyces cerevisiae." }, { "docid": "43752562", "text": "Subcellular membranes of Saccharomyces cerevisiae, including mitochondria, microsomes, plasma membranes, secretory vesicles, vacuoles, nuclear membranes, peroxisomes, and lipid particles, were isolated by improved procedures and analyzed for their lipid composition and their capacity to synthesize phospholipids and to catalyze sterol delta 24-methylation. The microsomal fraction is heterogeneous in terms of density and classical microsomal marker proteins and also with respect to the distribution of phospholipid-synthesizing enzymes. The specific activity of phosphatidylserine synthase was highest in a microsomal subfraction which was distinct from heavier microsomes harboring phosphatidylinositol synthase and the phospholipid N-methyltransferases. The exclusive location of phosphatidylserine decarboxylase in mitochondria was confirmed. CDO-diacylglycerol synthase activity was found both in mitochondria and in microsomal membranes. Highest specific activities of glycerol-3-phosphate acyltransferase and sterol delta 24-methyltransferase were observed in the lipid particle fraction. Nuclear and plasma membranes, vacuoles, and peroxisomes contain only marginal activities of the lipid-synthesizing enzymes analyzed. The plasma membrane and secretory vesicles are enriched in ergosterol and in phosphatidylserine. Lipid particles are characterized by their high content of ergosteryl esters. The rigidity of the plasma membrane and of secretory vesicles, determined by measuring fluorescence anisotropy by using trimethylammonium diphenylhexatriene as a probe, can be attributed to the high content of ergosterol.", "title": "Phospholipid synthesis and lipid composition of subcellular membranes in the unicellular eukaryote Saccharomyces cerevisiae." }, { "docid": "41087952", "text": "RIA1 (YNL163c) is a quasi-essential gene that encodes a protein with strong similarities to elongation factors 2. Small C-terminal deletions in the protein lead to a severe growth defect. In the case of a 22-residue C-terminal deletion this can be suppressed by intragenic mutations in the RIA1 gene or dominant extragenic mutations in TIF6, which is thought to be involved in the biogenesis of the 60S subunit of the ribosome. The dominant TIF6 alleles can also suppress the phenotype associated with a complete deletion of the RIA1 gene. Depletion of Ria1p has a dramatic effect on the polysome profile: there is a severe reduction in the level of the 80S monosomes, an imbalance in the 40S/60S ratio, and halfmers appear. Dissociation of the monosomes and polysomes in the Ria1p depletion mutant revealed a specific reduction in the amount of 60S subunits. Localization experiments with HA-tagged derivatives of Ria1p did not detect any stable association of Ria1p with ribosome subunits, 80S monosomes or polysomes. Cell fractionation experiments show that Ria1p is found in both the cytoplasmic fraction and the nuclear fraction. Taken together, these data suggest that Ria1p is involved in the biogenesis of the 60S subunit of the ribosome.", "title": "Ria1p (Ynl163c), a protein similar to elongation factors 2, is involved in the biogenesis of the 60S subunit of the ribosome in Saccharomyces cerevisiae" }, { "docid": "4324278", "text": "The rapamycin-sensitive TOR signalling pathway in Saccharomyces cerevisiae activates a cell-growth program in response to nutrients such as nitrogen and carbon. The TOR1 and TOR2 kinases (TOR) control cytoplasmic protein synthesis and degradation through the conserved TAP42 protein. Upon phosphorylation by TOR, TAP42 binds and possibly inhibits type 2A and type-2A-related phosphatases; however, the mechanism by which TOR controls nuclear events such as global repression of starvation-specific transcription is unknown. Here we show that TOR prevents transcription of genes expressed upon nitrogen limitation by promoting the association of the GATA transcription factor GLN3 with the cytoplasmic protein URE2. The binding of GLN3 to URE2 requires TOR-dependent phosphorylation of GLN3. Phosphorylation and cytoplasmic retention of GLN3 are also dependent on the TOR effector TAP42, and are antagonized by the type-2A-related phosphatase SIT4. TOR inhibits expression of carbon-source-regulated genes by stimulating the binding of the transcriptional activators MSN2 and MSN4 to the cytoplasmic 14-3-3 protein BMH2. Thus, the TOR signalling pathway broadly controls nutrient metabolism by sequestering several transcription factors in the cytoplasm.", "title": "The TOR signalling pathway controls nuclear localization of nutrient-regulated transcription factors." } ]

[ { "docid": "4398832", "text": "The most conspicuous event in the cell cycle is the alignment of chromosomes in metaphase. Chromosome alignment fosters faithful segregation through the formation of bi-oriented attachments of kinetochores to spindle microtubules. Notably, numerous kinetochore-microtubule (k-MT) attachment errors are present in early mitosis (prometaphase), and the persistence of those errors is the leading cause of chromosome mis-segregation in aneuploid human tumour cells that continually mis-segregate whole chromosomes and display chromosomal instability. How robust error correction is achieved in prometaphase to ensure error-free mitosis remains unknown. Here we show that k-MT attachments in prometaphase cells are considerably less stable than in metaphase cells. The switch to more stable k-MT attachments in metaphase requires the proteasome-dependent destruction of cyclin A in prometaphase. Persistent cyclin A expression prevents k-MT stabilization even in cells with aligned chromosomes. By contrast, k-MTs are prematurely stabilized in cyclin-A-deficient cells. Consequently, cells lacking cyclin A display higher rates of chromosome mis-segregation. Thus, the stability of k-MT attachments increases decisively in a coordinated fashion among all chromosomes as cells transit from prometaphase to metaphase. Cyclin A creates a cellular environment that promotes microtubule detachment from kinetochores in prometaphase to ensure efficient error correction and faithful chromosome segregation.", "title": "Cyclin A Regulates Kinetochore-Microtubules to Promote Faithful Chromosome Segregation" } ]

[ { "docid": "45875990", "text": "Cyclin A2 activates the cyclin-dependent kinases Cdk1 and Cdk2 and is expressed at elevated levels from S phase until early mitosis. We found that mutant mice that cannot elevate cyclin A2 are chromosomally unstable and tumor-prone. Underlying the chromosomal instability is a failure to up-regulate the meiotic recombination 11 (Mre11) nuclease in S phase, which leads to impaired resolution of stalled replication forks, insufficient repair of double-stranded DNA breaks, and improper segregation of sister chromosomes. Unexpectedly, cyclin A2 controlled Mre11 abundance through a C-terminal RNA binding domain that selectively and directly binds Mre11 transcripts to mediate polysome loading and translation. These data reveal cyclin A2 as a mechanistically diverse regulator of DNA replication combining multifaceted kinase-dependent functions with a kinase-independent, RNA binding–dependent role that ensures adequate repair of common replication errors.", "title": "Cyclin A2 is an RNA binding protein that controls Mre11 mRNA translation" }, { "docid": "600808", "text": "Cyclin A is a stable protein in S and G2 phases, but is destabilized when cells enter mitosis and is almost completely degraded before the metaphase to anaphase transition. Microinjection of antibodies against subunits of the anaphase-promoting complex/cyclosome (APC/C) or against human Cdc20 (fizzy) arrested cells at metaphase and stabilized both cyclins A and B1. Cyclin A was efficiently polyubiquitylated by Cdc20 or Cdh1-activated APC/C in vitro, but in contrast to cyclin B1, the proteolysis of cyclin A was not delayed by the spindle assembly checkpoint. The degradation of cyclin B1 was accelerated by inhibition of the spindle assembly checkpoint. These data suggest that the APC/C is activated as cells enter mitosis and immediately targets cyclin A for degradation, whereas the spindle assembly checkpoint delays the degradation of cyclin B1 until the metaphase to anaphase transition. The “destruction box” (D-box) of cyclin A is 10–20 residues longer than that of cyclin B. Overexpression of wild-type cyclin A delayed the metaphase to anaphase transition, whereas expression of cyclin A mutants lacking a D-box arrested cells in anaphase.", "title": "Anaphase-Promoting Complex/Cyclosome–Dependent Proteolysis of Human Cyclin a Starts at the Beginning of Mitosis and Is Not Subject to the Spindle Assembly Checkpoint" }, { "docid": "6472746", "text": "Chromosome segregation during cell division depends on stable attachment of kinetochores to spindle microtubules. Mitotic spindle formation and kinetochore-microtubule (K-MT) capture typically occur within minutes of nuclear envelope breakdown. In contrast, during meiosis I in mouse oocytes, formation of the acentrosomal bipolar spindle takes 3-4 h, and stabilization of K-MT attachments is delayed an additional 3-4 h. The mechanism responsible for this delay, which likely prevents stabilization of erroneous attachments during spindle formation, is unknown. Here we show that during meiosis I, attachments are regulated by CDK1 activity, which gradually increases through prometaphase and metaphase I. Partial reduction of CDK1 activity delayed formation of stable attachments, whereas a premature increase in CDK1 activity led to precocious formation of stable attachments and eventually lagging chromosomes at anaphase I. These results indicate that the slow increase in CDK1 activity in meiosis I acts as a timing mechanism to allow stable K-MT attachments only after bipolar spindle formation, thus preventing attachment errors.", "title": "Increased CDK1 activity determines the timing of kinetochore-microtubule attachments in meiosis I" }, { "docid": "14205246", "text": "The spindle apparatus is a microtubule (MT)-based machinery that attaches to and segregates the chromosomes during mitosis and meiosis. Self-organization of the spindle around chromatin involves the assembly of MTs, their attachment to the chromosomes, and their organization into a bipolar array. One regulator of spindle self-organization is RanGTP. RanGTP is generated at chromatin and activates a set of soluble, Ran-regulated spindle factors such as TPX2, NuMA, and NuSAP . How the spindle factors direct and attach MTs to the chromosomes are key open questions. Nucleolar and Spindle-Associated Protein (NuSAP) was recently identified as an essential MT-stabilizing and bundling protein that is enriched at the central part of the spindle . Here, we show by biochemical reconstitution that NuSAP efficiently adsorbs to isolated chromatin and DNA and that it can directly produce and retain high concentrations of MTs in the immediate vicinity of chromatin or DNA. Moreover, our data reveal that NuSAP-chromatin interaction is subject to Ran regulation and can be suppressed by Importin alpha (Impalpha) and Imp7. We propose that the presence of MT binding agents such as NuSAP, which can be directly immobilized on chromatin, are critical for targeting MT production to vertebrate chromosomes during spindle self-organization.", "title": "A Role for NuSAP in Linking Microtubules to Mitotic Chromosomes" }, { "docid": "14471161", "text": "Circadian disruption accelerates cancer progression, whereas circadian reinforcement could halt it. Mice with P03 pancreatic adenocarcinoma (n = 77) were synchronized and fed ad libitum (AL) or with meal timing (MT) from Zeitgeber time (ZT) 2 to ZT6 with normal or fat diet. Tumor gene expression profiling was determined with DNA microarrays at endogenous circadian time (CT) 4 and CT16. Circadian mRNA expression patterns were determined for clock genes Rev-erbalpha, Per2, and Bmal1, cellular stress genes Hspa8 and Cirbp, and cyclin A2 gene Ccna2 in liver and tumor. The 24-hour patterns in telemetered rest-activity and body temperature and plasma corticosterone and insulin-like growth factor-I (IGF-I) were assessed. We showed that MT inhibited cancer growth by approximately 40% as compared with AL (P = 0.011) irrespective of calorie intake. Clock gene transcription remained arrhythmic in tumors irrespective of feeding schedule or diet. Yet, MT upregulated or downregulated the expression of 423 tumor genes, according to CT. Moreover, 36 genes involved in cellular stress, cell cycle, and metabolism were upregulated at one CT and downregulated 12 h apart. MT induced >10-fold circadian expression of Hspa8, Cirbp, and Ccna2 in tumors. Corticosterone or IGF-I patterns played no role in tumor growth inhibition. In contrast, MT consistently doubled the circadian amplitude of body temperature. Peak and trough respectively corresponded to peak expressions of Hspa8 and Cirbp in tumors. The reinforcement of the host circadian timing system with MT induced 24-hour rhythmic expression of critical genes in clock-deficient tumors, which translated into cancer growth inhibition. Targeting circadian clocks represents a novel potential challenge for cancer therapeutics.", "title": "Cancer inhibition through circadian reprogramming of tumor transcriptome with meal timing." }, { "docid": "17805221", "text": "Sport fishermen keep tension on their lines to prevent hooked fish from releasing. A molecular version of this angler's trick, operating at kinetochores, ensures accuracy during mitosis: the mitotic spindle attaches randomly to chromosomes and then correctly bioriented attachments are stabilized due to the tension exerted on them by opposing microtubules. Incorrect attachments, which lack tension, are unstable and release quickly, allowing another chance for biorientation. Stabilization of molecular interactions by tension also occurs in other physiological contexts, such as cell adhesion, motility, hemostasis, and tissue morphogenesis. Here, we review models for the stabilization of kinetochore attachments with an eye toward emerging models for other force-activated systems. Although attention in the mitosis field has focused mainly on one kinase-based mechanism, multiple mechanisms may act together to stabilize properly bioriented kinetochores and some principles governing other tension-sensitive systems may also apply to kinetochores.", "title": "Catch and release: how do kinetochores hook the right microtubules during mitosis?" }, { "docid": "8087082", "text": "The microtubule (MT) cytoskeleton is required for many aspects of cell function, including the transport of intracellular materials, the maintenance of cell polarity, and the regulation of mitosis. These functions are coordinated by MT-associated proteins (MAPs), which work in concert with each other, binding MTs and altering their properties. We have used a MT cosedimentation assay, combined with 1D and 2D PAGE and mass spectrometry, to identify over 250 MAPs from early Drosophila embryos. We have taken two complementary approaches to analyse the cellular function of novel MAPs isolated using this approach. First, we have carried out an RNA interference (RNAi) screen, identifying 21 previously uncharacterised genes involved in MT organisation. Second, we have undertaken a bioinformatics analysis based on binary protein interaction data to produce putative interaction networks of MAPs. By combining both approaches, we have identified and validated MAP complexes with potentially important roles in cell cycle regulation and mitosis. This study therefore demonstrates that biologically relevant data can be harvested using such a multidisciplinary approach, and identifies new MAPs, many of which appear to be important in cell division.", "title": "A Microtubule Interactome: Complexes with Roles in Cell Cycle and Mitosis" }, { "docid": "23356816", "text": "The mammalian A-type cyclin family consists of two members, cyclin A1 (encoded by Ccna1) and cyclin A2 (encoded by Ccna2). Cyclin A2 promotes both G1/S and G2/M transitions, and targeted deletion of Ccna2 in mouse is embryonic lethal. Cyclin A1 is expressed in mice exclusively in the germ cell lineage and is expressed in humans at highest levels in the testis and certain myeloid leukaemia cells. To investigate the role of cyclin A1 and possible redundancy among the cyclins in vivo, we generated mice bearing a null mutation of Ccna1. Ccna1-/- males were sterile due to a block of spermatogenesis before the first meiotic division, whereas females were normal. Meiosis arrest in Ccna1–/– males was associated with increased germ cell apoptosis, desynapsis abnormalities and reduction of Cdc2 kinase activation at the end of meiotic prophase. Cyclin A1 is therefore essential for spermatocyte passage into the first meiotic division in male mice, a function that cannot be complemented by the concurrently expressed B-type cyclins.", "title": "Cyclin A1 is required for meiosis in the male mouse" }, { "docid": "7622767", "text": "We have used microinjection and time-lapse video microscopy to study the role of cyclin A in mitosis. We have injected purified, active cyclin A/cyclin-dependent kinase 2 (CDK2) into synchronized cells at specific points in the cell cycle and assayed its effect on cell division. We find that cyclin A/CDK2 will drive G2 phase cells into mitosis within 30 min of microinjection, up to 4 h before control cells enter mitosis. Often this premature mitosis is abnormal; the chromosomes do not completely condense and daughter cells fuse. Remarkably, microinjecting cyclin A/CDK2 into S phase cells has no effect on progress through the following G2 phase or mitosis. In complementary experiments we have microinjected the amino terminus of p21Cip1/Waf1/Sdi1 (p21N) into cells to inhibit cyclin A/CDK2 activity. We find that p21N will prevent S phase or G2 phase cells from entering mitosis, and will cause early prophase cells to return to interphase. These results suggest that cyclin A/CDK2 is a rate-limiting component required for entry into mitosis, and for progress through mitosis until late prophase. They also suggest that cyclin A/CDK2 may be the target of the recently described prophase checkpoint.", "title": "Human Cyclin a Is Required for Mitosis until Mid Prophase" }, { "docid": "11674596", "text": "A putative spindle matrix has been hypothesized to mediate chromosome motion, but its existence and functionality remain controversial. In this report, we show that Megator (Mtor), the Drosophila melanogaster counterpart of the human nuclear pore complex protein translocated promoter region (Tpr), and the spindle assembly checkpoint (SAC) protein Mad2 form a conserved complex that localizes to a nuclear derived spindle matrix in living cells. Fluorescence recovery after photobleaching experiments supports that Mtor is retained around spindle microtubules, where it shows distinct dynamic properties. Mtor/Tpr promotes the recruitment of Mad2 and Mps1 but not Mad1 to unattached kinetochores (KTs), mediating normal mitotic duration and SAC response. At anaphase, Mtor plays a role in spindle elongation, thereby affecting normal chromosome movement. We propose that Mtor/Tpr functions as a spatial regulator of the SAC, which ensures the efficient recruitment of Mad2 to unattached KTs at the onset of mitosis and proper spindle maturation, whereas enrichment of Mad2 in a spindle matrix helps confine the action of a diffusible \"wait anaphase\" signal to the vicinity of the spindle.", "title": "Spatiotemporal control of mitosis by the conserved spindle matrix protein Megator" }, { "docid": "493346", "text": "How sister kinetochores attach to microtubules from opposite spindle poles during mitosis (bi-orientation) remains poorly understood. In yeast, the ortholog of the Aurora B-INCENP protein kinase complex (Ipl1-Sli15) may have a role in this crucial process, because it is necessary to prevent attachment of sister kinetochores to microtubules from the same spindle pole. We investigated IPL1 function in cells that cannot replicate their chromosomes but nevertheless duplicate their spindle pole bodies (SPBs). Kinetochores detach from old SPBs and reattach to old and new SPBs with equal frequency in IPL1+ cells, but remain attached to old SPBs in ipl1 mutants. This raises the possibility that Ipl1-Sli15 facilitates bi-orientation by promoting turnover of kinetochore-SPB connections until traction of sister kinetochores toward opposite spindle poles creates tension in the surrounding chromatin.", "title": "Evidence that the Ipl1-Sli15 (Aurora Kinase-INCENP) Complex Promotes Chromosome Bi-orientation by Altering Kinetochore-Spindle Pole Connections" }, { "docid": "38127792", "text": "In mitosis the cell assembles the bipolar spindle, a microtubule (MT)-based apparatus that segregates the duplicated chromosomes into two daughter cells. Most animal cells enter mitosis with duplicated centrosomes that provide an active source of dynamic MTs. However, it is now established that spindle assembly relies on the nucleation of acentrosomal MTs occurring around the chromosomes after nuclear envelope breakdown, and on pre-existing microtubules. Where chromosome-dependent MT nucleation occurs, when MT amplification takes place and how the two pathways function are still key questions that generate some controversies. We reconcile the data and present an integrated model accounting for acentrosomal microtubule assembly in the dividing cell.", "title": "Acentrosomal Microtubule Assembly in Mitosis: The Where, When, and How." }, { "docid": "57121667", "text": "The ART-adherence club model described here provides patient-friendly access to antiretroviral therapy (ART) for clinically stable patients. It reduces the burden that stable patients place on healthcare facilities, increasing clinical human resources for new patients, and those clinically unstable and at risk of failing treatment. In the model, 30 patients are allocated to an ART club. The group meets either at a facility or community venue for less than an hour every 2 months. Group meetings are facilitated by a lay club facilitator who provides a quick clinical assessment, referral where necessary, and dispenses pre-packed ART. From January 2011 to December 2012, after adoption for phased rollout by the Western Cape Government, more than 600 ART clubs were established in Cape Town, providing ART care to over 16 000 patients. This extensive, rapid rollout demonstrates active buy-in from patients and facility staff. South Africa should consider a similar model for national rollout.", "title": "ART adherence clubs: A long-term retention strategy for clinically stable patients receiving antiretroviral therapy" }, { "docid": "2991954", "text": "Production of Ran-guanosine triphosphate (GTP) around chromosomes induces local nucleation and plus end stabilization of microtubules (MTs). The nuclear protein TPX2 is required for RanGTP-dependent MT nucleation. To find the MT stabilizer, we affinity purify nuclear localization signal (NLS)-containing proteins from Xenopus laevis egg extracts. This NLS protein fraction contains the MT stabilization activity. After further purification, we used mass spectrometry to identify proteins in active fractions, including cyclin-dependent kinase 11 (Cdk11). Cdk11 localizes on spindle poles and MTs in Xenopus culture cells and egg extracts. Recombinant Cdk11 demonstrates RanGTP-dependent MT stabilization activity, whereas a kinase-dead mutant does not. Inactivation of Cdk11 in egg extracts blocks RanGTP-dependent MT stabilization and dramatically decreases the spindle assembly rate. Simultaneous depletion of TPX2 completely inhibits centrosome-dependent spindle assembly. Our results indicate that Cdk11 is responsible for RanGTP-dependent MT stabilization around chromosomes and that this local stabilization is essential for normal rates of spindle assembly and spindle function.", "title": "Cdk11 is a RanGTP-dependent microtubule stabilization factor that regulates spindle assembly rate" }, { "docid": "1684489", "text": "BACKGROUND Production of the GTP-bound form of the Ran GTPase (RanGTP) around chromosomes induces spindle assembly by activating nuclear localization signal (NLS)-containing proteins. Several NLS proteins have been identified as spindle assembly factors, but the complexity of the process led us to search for additional proteins with distinct roles in spindle assembly. \n RESULTS We identify a chromatin-remodeling ATPase, CHD4, as a RanGTP-dependent microtubule (MT)-associated protein (MAP). MT binding occurs via the region containing an NLS and chromatin-binding domains. In Xenopus egg extracts and cultured cells, CHD4 largely dissociates from mitotic chromosomes and partially localizes to the spindle. Immunodepletion of CHD4 from egg extracts significantly reduces the quantity of MTs produced around chromatin and prevents spindle assembly. CHD4 RNAi in both HeLa and Drosophila S2 cells induces defects in spindle assembly and chromosome alignment in early mitosis, leading to chromosome missegregation. Further analysis in egg extracts and in HeLa cells reveals that CHD4 is a RanGTP-dependent MT stabilizer. Moreover, the CHD4-containing NuRD complex promotes organization of MTs into bipolar spindles in egg extracts. Importantly, this function of CHD4 is independent of chromatin remodeling. \n CONCLUSIONS Our results uncover a new role for CHD4 as a MAP required for MT stabilization and involved in generating spindle bipolarity.", "title": "CHD4 Is a RanGTP-Dependent MAP that Stabilizes Microtubules and Regulates Bipolar Spindle Formation" }, { "docid": "14145440", "text": "BACKGROUND DNA replication and mitosis are triggered by activation of kinase complexes, each made up of a cyclin and a cyclin-dependent kinase (Cdk). It had seemed possible that the association of Cdks with different classes of cyclins specifies whether S phase (replication) or M phase (mitosis) will occur. The recent finding that individual B-type cyclins (encoded by the genes CLB1-CLB6) can have functions in both processes in the budding yeast Saccharomyces cerevisiae casts doubt on this notion. \n RESULTS S. cerevisiae strains lacking C1b1-C1b4 undergo DNA replication once but fail to enter mitosis. We have isolated mutations in two genes, SIM1 and SIM2 (SIM2 is identical to SEC72), which allow such cells to undergo an extra round of DNA replication without mitosis. The Clb5 kinase, which promotes S phase, remains active during the G2-phase arrest of cells of the parental strain, but its activity declines rapidly in sim mutants. Increased expression of the CLB5 gene prevents re-replication. Thus, a cyclin B-kinase that promotes DNA replication in G1-phase cells can prevent re-replication in G2-phase cells. Inactivation of C1b kinases by expression of the specific C1b-Cdk1 inhibitor p40SIC1 is sufficient to induce a prereplicative state at origins of replication in cells blocked in G2/M phase by nocodazole. Re-activation of C1b-Cdk1 kinases induces a second round of DNA replication. \n CONCLUSIONS We propose that S-phase-promoting cyclin B--Cdk complexes prevent re-replication during S, G2 and M phases by inhibiting the transition of replication origins to a pre-replicative state. This model can explain both why origins 'fire' only once per S phase and why S phase is dependent on completion of the preceding M phase.", "title": "S-phase-promoting cyclin-dependent kinases prevent re-replication by inhibiting the transition of replication origins to a pre-replicative state" }, { "docid": "29863668", "text": "The P446L mutant Drosophila importin-beta (P446L-imp-beta) has been reported to prohibit--in dominant negative fashion--nuclear envelope (NE) assembly. Along elucidating the mode of action of P446L-imp-beta we studied in vitro NE assembly on Sepharose beads. While Drosophila embryo extracts support NE assembly over Sepharose beads coated with Ran, NE assembly does not take place in extracts supplied with exogenous P446L-imp-beta. A NE also forms over importin-beta-coated beads. Surprisingly, when immobilized to Sepharose beads P446L-imp-beta as efficiently recruits NE vesicles as normal importin-beta. The discrepancy in behavior of cytoplasmic and bead-bound P446L-imp-beta appears to be related to icreased--as compared to normal importin-beta--microtubule (MT) binding ability of P446L-imp-beta. While wild-type importin-beta is able to bind MTs and the binding decreases upon RanGTP interaction, P446L-imp-beta cannot be removed from the MTs by RanGTP. P446L-imp-beta, like normal importin-beta, binds some types of the nucleoporins that have been known to be required for NE assembly at the end of mitosis. It appears that the inhibitory effect of P446L-imp-beta on NE assembly is caused by sequestering some of the nucleoporins required for NE assembly to the MTs.", "title": "P446L-importin-beta inhibits nuclear envelope assembly by sequestering nuclear envelope assembly factors to the microtubules." }, { "docid": "8698857", "text": "TNF expression of macrophages is under stringent translational control that depends on the p38 MAPK/MK2 pathway and the AU-rich element (ARE) in the TNF mRNA. Here, we elucidate the molecular mechanism of phosphorylation-regulated translation of TNF. We demonstrate that translation of the TNF-precursor at the ER requires expression of the ARE-binding and -stabilizing factor human antigen R (HuR) together with either activity of the p38 MAPK/MK2 pathway or the absence of the ARE-binding and -destabilizing factor tristetraprolin (TTP). We show that phosphorylation of TTP by MK2 decreases its affinity to the ARE, inhibits its ability to replace HuR, and permits HuR-mediated initiation of translation of TNF mRNA. Since translation of TTP's own mRNA is also regulated by this mechanism, an intrinsic feedback control of the inflammatory response is ensured. The phosphorylation-regulated TTP/HuR exchange at target mRNAs provides a reversible switch between unstable/non-translatable and stable/efficiently translated mRNAs.", "title": "The p38/MK2-Driven Exchange between Tristetraprolin and HuR Regulates AU–Rich Element–Dependent Translation" }, { "docid": "39929509", "text": "Mutations in WT1 are associated with developmental syndromes that affect the urogenital system and neoplasms, including Wilms tumour, acute myeloid leukemia, and breast and prostate cancers. The WT1 protein belongs to the early growth response family of zinc-finger transcription factors. Uniquely to WT1, an evolutionarily conserved alternative splice event inserts the tripeptide KTS, between zinc fingers 3 and 4. Whereas -KTS isoforms bind DNA and activate or repress transcription, +KTS isoforms bind DNA less efficiently and interact with splice factors and RNA in vitro and in vivo. Although candidate DNA targets have been found, physiological mRNA targets are yet to be defined. We examined the distribution of WT1 in ribonucleoprotein (RNP) complexes in nuclear extract prepared from M15 cells, a mouse mesonephric fetal kidney cell line. WT1 cofractionated with the splice factor PSF in large RNP particles >or=2 MDa. We also found that PSF co-immunoprecipitated with WT1, suggesting a functional interaction between these 2 multifunctional proteins. Using yeast three-hybrid library constructed from the co-immunoprecipitated RNA we found that WT1 (+KTS) binds close to or at the start codon of alpha-actinin 1 (ACTN1) mRNA. A band shift assay confirmed the ability of the WT1 zinc-finger domain (+KTS) to bind this sequence in vitro. ACTN1 is the first likely physiological mRNA target of WT1.", "title": "The Wilms tumour suppressor protein WT1 (+KTS isoform) binds alpha-actinin 1 mRNA via its zinc-finger domain." } ]

[ { "docid": "39381118", "text": "Apoptosis that proceeds via the mitochondrial pathway involves mitochondrial outer membrane permeabilization (MOMP), responsible for the release of cytochrome c and other proteins of the mitochondrial intermembrane space. This essential step is controlled and mediated by proteins of the Bcl-2 family. The proapoptotic proteins Bax and Bak are required for MOMP, while the antiapoptotic Bcl-2 proteins, including Bcl-2, Bcl-xL, Mcl-1, and others, prevent MOMP. Different proapoptotic BH3-only proteins act to interfere with the function of the antiapoptotic Bcl-2 members and/or activate Bax and Bak. Here, we discuss an emerging view, proposed by Certo et al. in this issue of Cancer Cell, on how these interactions result in MOMP and apoptosis.", "title": "At the gates of death." } ]

[ { "docid": "23403754", "text": "In this review I summarize interrelations between bioenergetic processes and such programmed death phenomena as cell suicide (apoptosis and necrosis) and mitochondrial suicide (mitoptosis). The following conclusions are made. (I) ATP and rather often mitochondrial hyperpolarization (i.e. an increase in membrane potential, ΔΨ) are required for certain steps of apoptosis and necrosis. (II) Apoptosis, even if it is accompanied by ΔΨ and [ATP] increases at its early stage, finally results in a ΔΨ collapse and ATP decrease. (III) Moderate (about three-fold) lowering of [ATP] for short and long periods of time induces apoptosis and necrosis, respectively. In some types of apoptosis and necrosis, the cell death is mediated by a ΔΨ-dependent overproduction of ROS by the initial (Complex I) and the middle (Complex III) spans of the respiratory chain. ROS initiate mitoptosis which is postulated to rid the intracellular population of mitochondria from those that are ROS overproducing. Massive mitoptosis can result in cell death due to release to cytosol of the cell death proteins normally hidden in the mitochondrial intermembrane space.", "title": "Bioenergetic aspects of apoptosis, necrosis and mitoptosis" }, { "docid": "9588931", "text": "Vascular calcification is a strong independent predictor of increased cardiovascular morbidity and mortality and has a high prevalence among patients with chronic kidney disease. The present study investigated the effects of quercetin on vascular calcification caused by oxidative stress and abnormal mitochondrial dynamics both in vitro and in vivo. Calcifying vascular smooth muscle cells (VSMCs) treated with inorganic phosphate (Pi) exhibited mitochondrial dysfunction, as demonstrated by decreased mitochondrial potential and ATP production. Disruption of mitochondrial structural integrity was also observed in a rat model of adenine-induced aortic calcification. Increased production of reactive oxygen species, enhanced expression and phosphorylation of Drp1, and excessive mitochondrial fragmentation were also observed in Pi-treated VSMCs. These effects were accompanied by mitochondria-dependent apoptotic events, including release of cytochrome c from the mitochondria into the cytosol and subsequent activation of caspase-3. Quercetin was shown to block Pi-induced apoptosis and calcification of VSMCs by inhibiting oxidative stress and decreasing mitochondrial fission by inhibiting the expression and phosphorylation of Drp1. Quercetin also significantly ameliorated adenine-induced aortic calcification in rats. In summary, our findings suggest that quercetin attenuates calcification by reducing apoptosis of VSMCs by blocking oxidative stress and inhibiting mitochondrial fission.", "title": "Quercetin attenuates vascular calcification by inhibiting oxidative stress and mitochondrial fission." }, { "docid": "10698739", "text": "Loss of Omi/HtrA2 function leads to nerve cell loss in mouse models and has been linked to neurodegeneration in Parkinson's and Huntington's disease. Omi/HtrA2 is a serine protease released as a pro-apoptotic factor from the mitochondrial intermembrane space into the cytosol. Under physiological conditions, Omi/HtrA2 is thought to be involved in protection against cellular stress, but the cytological and molecular mechanisms are not clear. Omi/HtrA2 deficiency caused an accumulation of reactive oxygen species and reduced mitochondrial membrane potential. In Omi/HtrA2 knockout mouse embryonic fibroblasts, as well as in Omi/HtrA2 silenced human HeLa cells and Drosophila S2R+ cells, we found elongated mitochondria by live cell imaging. Electron microscopy confirmed the mitochondrial morphology alterations and showed abnormal cristae structure. Examining the levels of proteins involved in mitochondrial fusion, we found a selective up-regulation of more soluble OPA1 protein. Complementation of knockout cells with wild-type Omi/HtrA2 but not with the protease mutant [S306A]Omi/HtrA2 reversed the mitochondrial elongation phenotype and OPA1 alterations. Finally, co-immunoprecipitation showed direct interaction of Omi/HtrA2 with endogenous OPA1. Thus, we show for the first time a direct effect of loss of Omi/HtrA2 on mitochondrial morphology and demonstrate a novel role of this mitochondrial serine protease in the modulation of OPA1. Our results underscore a critical role of impaired mitochondrial dynamics in neurodegenerative disorders.", "title": "Modulation of mitochondrial function and morphology by interaction of Omi/HtrA2 with the mitochondrial fusion factor OPA1." }, { "docid": "15836115", "text": "Mitochondrial morphological and ultrastructural changes occur during apoptosis and autophagy, but whether they are relevant in vivo for tissue response to damage is unclear. Here we investigate the role of the optic atrophy 1 (OPA1)-dependent cristae remodeling pathway in vivo and provide evidence that it regulates the response of multiple tissues to apoptotic, necrotic, and atrophic stimuli. Genetic inhibition of the cristae remodeling pathway in vivo does not affect development, but protects mice from denervation-induced muscular atrophy, ischemic heart and brain damage, as well as hepatocellular apoptosis. Mechanistically, OPA1-dependent mitochondrial cristae stabilization increases mitochondrial respiratory efficiency and blunts mitochondrial dysfunction, cytochrome c release, and reactive oxygen species production. Our results indicate that the OPA1-dependent cristae remodeling pathway is a fundamental, targetable determinant of tissue damage in vivo.", "title": "The Opa1-Dependent Mitochondrial Cristae Remodeling Pathway Controls Atrophic, Apoptotic, and Ischemic Tissue Damage" }, { "docid": "8654183", "text": "BACKGROUND AND AIMS Previous in vitro and in vivo studies have revealed an association between Helicobacter pylori infection and apoptosis in gastric epithelial cells. Although involvement of the Bcl-2 family of proteins as well as cytochrome c release has been demonstrated in H pylori induced cell death, the exact role of the mitochondria during this type of programmed cell death has not been fully elucidated. Therefore, we sought to determine whether or not Bax translocation and mitochondrial fragmentation occur on exposure of gastric epithelial cells to H pylori, resulting in cell death. \n METHODS Experiments were performed with human gastric adenocarcinoma (AGS) cells, AGS cells transfected with the HPV-E6 gene (which inactivates p53 function), AGS-neo cells (transfected with the backbone construct), mouse embryonic fibroblasts (MEFs), and p19(ARF) null (ARF(-/-)) MEFs. Cells were incubated with a cag positive H pylori strain for up to 24 hours, lysed, and cytoplasmic and mitochondrial membrane fractions were analysed by western blot for Bax translocation. \n RESULTS Bax translocation was detected in AGS, AGS-neo, and normal MEF cells after exposure to H pylori for three hours, but not in ARF(-/-) MEFs cells. Translocation of Bax after H pylori incubation was also detected in AGS-E6 cells (inactive p53 gene) but to a lesser degree than in AGS-neo cells. In parallel studies, the mitochondrial morphology of living cells infected with H pylori was assessed by confocal microscopy. Mitochondrial fragmentation was detectable after 10 hours of H pylori incubation with AGS cells and after seven hours with MEF cells. In wild-type MEFs, mitochondrial fragmentation was significantly increased in comparison with ARF null MEFs (43% v 10.4%, respectively). Furthermore, mitochondrial depolarisation and caspase-3 activity were initiated within four hours in cells incubated with H pylori, and these events were inhibited by forced expression of Bcl-2. \n CONCLUSIONS These data suggest that during H pylori induced apoptosis, Bax translocates to the mitochondria which subsequently undergo depolarisation and profound fragmentation. Functional ARF and p53 proteins may play an important role in H pylori induced mitochondrial modification.", "title": "Bax translocation and mitochondrial fragmentation induced by Helicobacter pylori." }, { "docid": "7465900", "text": "BACKGROUND & AIMS Helicobacter pylori-induced gastric epithelial cell (GEC) apoptosis is a complex process that includes activation of the tumor suppressor p53. p53-mediated apoptosis involves p53 activation, bax transcription, and cytochrome c release from mitochondria. Apurinic/apyrimidinic endonuclease-1 (APE-1) regulates transcriptional activity of p53, and H pylori induce APE-1 expression in human GECs. H pylori infection increases intracellular calcium ion concentration [Ca2+]i of GECs, which induces APE-1 acetylation. We investigated the effects of H pylori infection and APE-1 acetylation on GEC apoptosis. \n METHODS AGS cells (wild-type or with suppressed APE-1), KATO III cells, and cells isolated from gastric biopsy specimens were infected with H pylori. Effects were examined by immunoblotting, real-time reverse-transcription polymerase chain reaction, immunoprecipitation, immunofluorescence microscopy, chromatin immunoprecipitation, mobility shift, DNA binding, and luciferase assays. \n RESULTS H pylori infection increased [Ca2+]i and acetylation of APE-1 in GECs, but the acetylation status of APE-1 did not affect the transcriptional activity of p53. In GECs, expression of a form of APE-1 that could not be acetylated increased total and mitochondrial levels of Bax and induced release of cytochrome c and fragmentation of DNA; expression of wild-type APE-1 reduced these apoptotic events. We identified a negative calcium response element in the human bax promoter and found that poly (adenosine diphosphate-ribose) polymerase 1 recruited the acetylated APE-1/histone deacetylase-1 repressor complex to bax nCaRE. \n CONCLUSIONS H pylori-mediated acetylation of APE-1 suppresses Bax expression; this prevents p53-mediated apoptosis when H pylori infect GECs.", "title": "Acetylation of apurinic/apyrimidinic endonuclease-1 regulates Helicobacter pylori-mediated gastric epithelial cell apoptosis." }, { "docid": "25439264", "text": "Abstract Hyperhomocysteinemia has been suggested as a possible risk factor in women suffering from habitual abortions, placental abruption or infarcts, preeclampsia, and/or intrauterine growth retardation. However, little is known about the pathogenic mechanisms underlying the action of homocysteine. The present study investigated the in vitro ability of homocysteine to affect trophoblast gonadotropin secretion and to induce cell death. In primary human trophoblast cells, homocysteine treatment (20 μmol/L) resulted in cellular flattening and enlargement, extension of pseudopodia, and cellular vacuolization. Cellular detachment, apoptosis, and necrosis were favored. With in situ nick end labeling, we investigated DNA degradation, and we used M30 CytoDEATH to selectively stain the cytoplasm of apoptotic cells. Cytochrome c release from mitochondria to the cytosol and DNA cleavage in agarose gel have been investigated. Homocysteine, but not cysteine, induced trophoblast apoptosis and significantly reduced human chorionic gonadotropin secretion. These findings suggest that trophoblast cell death might represent a pathogenic mechanism by which homocysteine may cause pregnancy complications related to placental diseases.", "title": "Homocysteine Induces Trophoblast Cell Death with Apoptotic Features1" }, { "docid": "23887844", "text": "Neurons and cancer cells use glucose extensively, yet the precise advantage of this adaptation remains unclear. These two seemingly disparate cell types also show an increased regulation of the apoptotic pathway, which allows for their long-term survival. Here we show that both neurons and cancer cells strictly inhibit cytochrome c-mediated apoptosis by a mechanism dependent on glucose metabolism. We report that the pro-apoptotic activity of cytochrome c is influenced by its redox state and that increases in reactive oxygen species (ROS) following an apoptotic insult lead to the oxidation and activation of cytochrome c. In healthy neurons and cancer cells, however, cytochrome c is reduced and held inactive by intracellular glutathione (GSH), generated as a result of glucose metabolism by the pentose phosphate pathway. These results uncover a striking similarity in apoptosis regulation between neurons and cancer cells and provide insight into an adaptive advantage offered by the Warburg effect for cancer cell evasion of apoptosis and for long-term neuronal survival.", "title": "Glucose Metabolism Inhibits Apoptosis in Neurons and Cancer Cells by Redox Inactivation of Cytochrome c" }, { "docid": "3553087", "text": "Chronic obstructive pulmonary disease (COPD) is linked to both cigarette smoking and genetic determinants. We have previously identified iron-responsive element-binding protein 2 (IRP2) as an important COPD susceptibility gene and have shown that IRP2 protein is increased in the lungs of individuals with COPD. Here we demonstrate that mice deficient in Irp2 were protected from cigarette smoke (CS)-induced experimental COPD. By integrating RNA immunoprecipitation followed by sequencing (RIP-seq), RNA sequencing (RNA-seq), and gene expression and functional enrichment clustering analysis, we identified Irp2 as a regulator of mitochondrial function in the lungs of mice. Irp2 increased mitochondrial iron loading and levels of cytochrome c oxidase (COX), which led to mitochondrial dysfunction and subsequent experimental COPD. Frataxin-deficient mice, which had higher mitochondrial iron loading, showed impaired airway mucociliary clearance (MCC) and higher pulmonary inflammation at baseline, whereas mice deficient in the synthesis of cytochrome c oxidase, which have reduced COX, were protected from CS-induced pulmonary inflammation and impairment of MCC. Mice treated with a mitochondrial iron chelator or mice fed a low-iron diet were protected from CS-induced COPD. Mitochondrial iron chelation also alleviated CS-induced impairment of MCC, CS-induced pulmonary inflammation and CS-associated lung injury in mice with established COPD, suggesting a critical functional role and potential therapeutic intervention for the mitochondrial-iron axis in COPD.", "title": "Mitochondrial iron chelation ameliorates cigarette-smoke induced bronchitis and emphysema in mice" }, { "docid": "6259170", "text": "Nuclear factor erythroid-derived 2-related factor 2 (Nrf2) was originally identified as a positive regulator of drug detoxifying enzyme gene expression during exposure to environmental electrophiles. Currently, Nrf2 is known to regulate the expression of hundreds of cytoprotective genes to counteract endogenously or exogenously generated oxidative stress. Furthermore, when activated in human tumors by somatic mutations, Nrf2 confers growth advantages and chemoresistance by regulating genes involved in various processes such as the pentose phosphate pathway and nucleotide synthesis in addition to antioxidant proteins. Interestingly, increasing evidence shows that Nrf2 is associated with mitochondrial biogenesis during environmental stresses in certain tissues such as the heart. Furthermore, SKN-1, a functional homolog of Nrf2 in C. elegans, is activated by mitochondrial reactive oxygen species and extends life span by promoting mitochondrial homeostasis (i.e., mitohormesis). Similarly, Nrf2 activation was recently observed in the heart of surfeit locus protein 1 (Surf1) -/- mice in which cellular respiration was decreased due to cytochrome c oxidase defects. In this review, we critically examine the relationship between Nrf2 and mitochondria and argue that the Nrf2 stress pathway intimately communicates with mitochondria to maintain cellular homeostasis during oxidative stress.", "title": "Emerging functional cross-talk between the Keap1-Nrf2 system and mitochondria" }, { "docid": "10852047", "text": "We recently developed a class of novel antitumor agents that elicit a potent growth-inhibitory response in many tumor cells cultured in vitro. WK175, a member of this class, was chosen as a model compound that showed strong in vitro efficacy. WK175 interferes with the intracellular steady-state level of NAD(+), resulting in a decreased cellular NAD(+) concentration. We found that WK175 induces apoptotic cell death without any DNA-damaging effect. The apoptotic death signaling pathway initiated by WK175 was examined in detail: mitochondrial membrane potential, cytochrome c release, caspase 3 activation, caspase 3 and poly(ADP-ribose) polymerase cleavage, and the appearance of a sub-G(1) cell cycle population were determined in time course studies in THP-1 (a human monocytic leukemia cell line) cells. We found activation of this cascade after 24 h of treatment with 10 nM WK175. Induction of apoptosis was prevented by bongkrekic acid, Z-Asp-Glu-Val-Asp-fluoromethylketone, and Z-Leu-Glu-His-Asp-fluoromethylketone, inhibitors of the mitochondrial permeability transition and of caspase 3 and 9, respectively, but not by Ac-Tyr-Val-Ala-Asp-CHO, a specific caspase 1 inhibitor, suggesting the involvement of the permeability transition pore, caspase 3, and caspase 9 in the WK175-induced apoptotic cascade. These results imply that decreased NAD(+) concentration initiates the apoptotic cascade, resulting in the antitumor effect of WK175.", "title": "WK175, a novel antitumor agent, decreases the intracellular nicotinamide adenine dinucleotide concentration and induces the apoptotic cascade in human leukemia cells." }, { "docid": "34439544", "text": "The BCL-2 (B cell CLL/Lymphoma) family is comprised of approximately twenty proteins that collaborate to either maintain cell survival or initiate apoptosis(1). Following cellular stress (e.g., DNA damage), the pro-apoptotic BCL-2 family effectors BAK (BCL-2 antagonistic killer 1) and/or BAX (BCL-2 associated X protein) become activated and compromise the integrity of the outer mitochondrial membrane (OMM), though the process referred to as mitochondrial outer membrane permeabilization (MOMP)(1). After MOMP occurs, pro-apoptotic proteins (e.g., cytochrome c) gain access to the cytoplasm, promote caspase activation, and apoptosis rapidly ensues(2). In order for BAK/BAX to induce MOMP, they require transient interactions with members of another pro-apoptotic subset of the BCL-2 family, the BCL-2 homology domain 3 (BH3)-only proteins, such as BID (BH3-interacting domain agonist)(3-6). Anti-apoptotic BCL-2 family proteins (e.g., BCL-2 related gene, long isoform, BCL-xL; myeloid cell leukemia 1, MCL-1) regulate cellular survival by tightly controlling the interactions between BAK/BAX and the BH3-only proteins capable of directly inducing BAK/BAX activation(7,8). In addition, anti-apoptotic BCL-2 protein availability is also dictated by sensitizer/de-repressor BH3-only proteins, such as BAD (BCL-2 antagonist of cell death) or PUMA (p53 upregulated modulator of apoptosis), which bind and inhibit anti-apoptotic members(7,9). As most of the anti-apoptotic BCL-2 repertoire is localized to the OMM, the cellular decision to maintain survival or induce MOMP is dictated by multiple BCL-2 family interactions at this membrane. Large unilamellar vesicles (LUVs) are a biochemical model to explore relationships between BCL-2 family interactions and membrane permeabilization(10). LUVs are comprised of defined lipids that are assembled in ratios identified in lipid composition studies from solvent extracted Xenopus mitochondria (46.5% phosphatidylcholine, 28.5% phosphatidylethanoloamine, 9% phosphatidylinositol, 9% phosphatidylserine, and 7% cardiolipin)(10). This is a convenient model system to directly explore BCL-2 family function because the protein and lipid components are completely defined and tractable, which is not always the case with primary mitochondria. While cardiolipin is not usually this high throughout the OMM, this model does faithfully mimic the OMM to promote BCL-2 family function. Furthermore, a more recent modification of the above protocol allows for kinetic analyses of protein interactions and real-time measurements of membrane permeabilization, which is based on LUVs containing a polyanionic dye (ANTS: 8-aminonaphthalene-1,3,6-trisulfonic acid) and cationic quencher (DPX: p-xylene-bis-pyridinium bromide)(11). As the LUVs permeabilize, ANTS and DPX diffuse apart, and a gain in fluorescence is detected. Here, commonly used recombinant BCL-2 family protein combinations and controls using the LUVs containing ANTS/DPX are described.", "title": "Examining BCL-2 family function with large unilamellar vesicles." }, { "docid": "35962023", "text": "Recent studies suggest a close relationship between cell metabolism and apoptosis. We have evaluated changes in lipid metabolism on permeabilized hepatocytes treated with truncated Bid (tBid) in the presence of caspase inhibitors and exogenous cytochrome c. The measurement of β-oxidation flux by labeled palmitate demonstrates that tBid inhibits β-oxidation, thereby resulting in the accumulation of palmitoyl-coenzyme A (CoA) and depletion of acetyl-carnitine and acylcarnitines, which is pathognomonic for inhibition of carnitine palmitoyltransferase-1 (CPT-1). We also show that tBid decreases CPT-1 activity by a mechanism independent of both malonyl-CoA, the key inhibitory molecule of CPT-1, and Bak and/or Bax, but dependent on cardiolipin decrease. Overexpression of Bcl-2, which is able to interact with CPT-1, counteracts the effects exerted by tBid on β-oxidation. The unexpected role of tBid in the regulation of lipid β-oxidation suggests a model in which tBid-induced metabolic decline leads to the accumulation of toxic lipid metabolites such as palmitoyl-CoA, which might become participants in the apoptotic pathway.", "title": "tBid induces alterations of mitochondrial fatty acid oxidation flux by malonyl-CoA-independent inhibition of carnitine palmitoyltransferase-1" }, { "docid": "40232172", "text": "The research on mitochondrial functions in adipocytes has increasingly evidenced that mitochondria plays an important role in the onset and/or progression of obesity and related pathologies. Mitochondrial function in brown adipose tissue (BAT) has been classically assessed by measuring either the levels/activity of mitochondrial enzymes, or the respiration in isolated mitochondria. Isolation of mitochondria is not advantageous because it demands significant time and amount of tissue and, as tissue homogenates, disrupts biochemical and physical connections of mitochondria within the cell. Here, we described a new and efficient protocol to analyze the mitochondrial respiratory states in BAT biopsies that relies on intracellular triglyceride depletion followed by tissue permeabilization. In addition to minimizing tissue requirements to ∼17 mg wet weight, the proposed protocol enabled analysis of all mitochondrial respiratory states, including phosphorylation (OXPHOS), no-phosphorylation (LEAK), and uncoupled (ETS) states, as well as the use of substrates for complex I, complex II, and cytochrome c; together, these features demonstrated mitochondrial integrity and validated the preparation efficacy. Therefore, the protocol described here increases the possibilities of answering physiological questions related to small BAT regions of human and animal models, which shall help to unravel the mechanisms that regulate mitochondrial function in health and disease.", "title": "Triglyceride depletion of brown adipose tissue enables analysis of mitochondrial respiratory function in permeabilized biopsies." }, { "docid": "17231273", "text": "Energy deficiency and dysfunction of the Na+, K+-ATPase are common consequences of many pathological insults. The nature and mechanism of cell injury induced by impaired Na+, K+-ATPase, however, are not well defined. We used cultured cortical neurons to examine the hypothesis that blocking the Na+, K+-ATPase induces apoptosis by depleting cellular K+ and, concurrently, induces necrotic injury in the same cells by increasing intracellular Ca2+ and Na+. The Na+, K+-ATPase inhibitor ouabain induced concentration-dependent neuronal death. Ouabain triggered transient neuronal cell swelling followed by cell shrinkage, accompanied by intracellular Ca2+ and Na+ increase, K+ decrease, cytochrome c release, caspase-3 activation, and DNA laddering. Electron microscopy revealed the coexistence of ultrastructural features of both apoptosis and necrosis in individual cells. The caspase inhibitor Z-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD-FMK) blocked >50% of ouabain-induced neuronal death. Potassium channel blockers or high K+ medium, but not Ca2+ channel blockade, prevented cytochrome c release, caspase activation, and DNA damage. Blocking of K+, Ca2+, or Na+ channels or high K+ medium each attenuated the ouabain-induced cell death; combined inhibition of K+ channels and Ca2+ or Na+ channels resulted in additional protection. Moreover, coapplication of Z-VAD-FMK and nifedipine produced virtually complete neuroprotection. These results suggest that the neuronal death associated with Na+, K+-pump failure consists of concurrent apoptotic and necrotic components, mediated by intracellular depletion of K+ and accumulation of Ca2+ and Na+, respectively. The ouabain-induced hybrid death may represent a distinct form of cell death related to the brain injury of inadequate energy supply and disrupted ion homeostasis.", "title": "Ionic mechanism of ouabain-induced concurrent apoptosis and necrosis in individual cultured cortical neurons" }, { "docid": "15248287", "text": "Neutrophil apoptosis is a highly regulated process essential for inflammation resolution, the molecular mechanisms of which are only partially elucidated. In this study, we describe a survival pathway controlled by proliferating cell nuclear antigen (PCNA), a nuclear factor involved in DNA replication and repairing of proliferating cells. We show that mature neutrophils, despite their inability to proliferate, express high levels of PCNA exclusively in their cytosol and constitutively associated with procaspases, presumably to prevent their activation. Notably, cytosolic PCNA abundance decreased during apoptosis, and increased during in vitro and in vivo exposure to the survival factor granulocyte colony-stimulating factor (G-CSF). Peptides derived from the cyclin-dependent kinase inhibitor p21, which compete with procaspases to bind PCNA, triggered neutrophil apoptosis thus demonstrating that specific modification of PCNA protein interactions affects neutrophil survival. Furthermore, PCNA overexpression rendered neutrophil-differentiated PLB985 myeloid cells significantly more resistant to TNF-related apoptosis-inducing ligand- or gliotoxin-induced apoptosis. Conversely, a decrease in PCNA expression after PCNA small interfering RNA transfection sensitized these cells to apoptosis. Finally, a mutation in the PCNA interdomain-connecting loop, the binding site for many partners, significantly decreased the PCNA-mediated antiapoptotic effect. These results identify PCNA as a regulator of neutrophil lifespan, thereby highlighting a novel target to potentially modulate pathological inflammation.", "title": "Proliferating cell nuclear antigen acts as a cytoplasmic platform controlling human neutrophil survival" }, { "docid": "3883485", "text": "Replacement of mitochondria through nuclear transfer between oocytes of two different women has emerged recently as a strategy for preventing inheritance of mtDNA diseases. Although experiments in human oocytes have shown effective replacement, the consequences of small amounts of mtDNA carryover have not been studied sufficiently. Using human mitochondrial replacement stem cell lines, we show that, even though the low levels of heteroplasmy introduced into human oocytes by mitochondrial carryover during nuclear transfer often vanish, they can sometimes instead result in mtDNA genotypic drift and reversion to the original genotype. Comparison of cells with identical oocyte-derived nuclear DNA but different mtDNA shows that either mtDNA genotype is compatible with the nucleus and that drift is independent of mitochondrial function. Thus, although functional replacement of the mitochondrial genome is possible, even low levels of heteroplasmy can affect the stability of the mtDNA genotype and compromise the efficacy of mitochondrial replacement.", "title": "Genetic Drift Can Compromise Mitochondrial Replacement by Nuclear Transfer in Human Oocytes." }, { "docid": "2601324", "text": "Oligodendrocytes, the myelin-forming glial cells of the central nervous system, maintain long-term axonal integrity. However, the underlying support mechanisms are not understood. Here we identify a metabolic component of axon–glia interactions by generating conditional Cox10 (protoheme IX farnesyltransferase) mutant mice, in which oligodendrocytes and Schwann cells fail to assemble stable mitochondrial cytochrome c oxidase (COX, also known as mitochondrial complex IV). In the peripheral nervous system, Cox10 conditional mutants exhibit severe neuropathy with dysmyelination, abnormal Remak bundles, muscle atrophy and paralysis. Notably, perturbing mitochondrial respiration did not cause glial cell death. In the adult central nervous system, we found no signs of demyelination, axonal degeneration or secondary inflammation. Unlike cultured oligodendrocytes, which are sensitive to COX inhibitors, post-myelination oligodendrocytes survive well in the absence of COX activity. More importantly, by in vivo magnetic resonance spectroscopy, brain lactate concentrations in mutants were increased compared with controls, but were detectable only in mice exposed to volatile anaesthetics. This indicates that aerobic glycolysis products derived from oligodendrocytes are rapidly metabolized within white matter tracts. Because myelinated axons can use lactate when energy-deprived, our findings suggest a model in which axon–glia metabolic coupling serves a physiological function.", "title": "Glycolytic oligodendrocytes maintain myelin and long-term axonal integrity" }, { "docid": "14915566", "text": "Debate exists over how to incorporate information from multipartite sequence data in phylogenetic analyses. Strict combined-data approaches argue for concatenation of all partitions and estimation of one evolutionary history, maximizing the explanatory power of the data. Consensus/independence approaches endorse a two-step procedure where partitions are analyzed independently and then a consensus is determined from the multiple results. Mixtures across the model space of a strict combined-data approach and a priori independent parameters are popular methods to integrate these methods. We propose an alternative middle ground by constructing a Bayesian hierarchical phylogenetic model. Our hierarchical framework enables researchers to pool information across data partitions to improve estimate precision in individual partitions while permitting estimation and testing of tendencies in across-partition quantities. Such across-partition quantities include the distribution from which individual topologies relating the sequences within a partition are drawn. We propose standard hierarchical priors on continuous evolutionary parameters across partitions, while the structure on topologies varies depending on the research problem. We illustrate our model with three examples. We first explore the evolutionary history of the guinea pig (Cavia porcellus) using alignments of 13 mitochondrial genes. The hierarchical model returns substantially more precise continuous parameter estimates than an independent parameter approach without losing the salient features of the data. Second, we analyze the frequency of horizontal gene transfer using 50 prokaryotic genes. We assume an unknown species-level topology and allow individual gene topologies to differ from this with a small estimable probability. Simultaneously inferring the species and individual gene topologies returns a transfer frequency of 17%. We also examine HIV sequences longitudinally sampled from HIV+ patients. We ask whether posttreatment development of CCR5 coreceptor virus represents concerted evolution from middisease CXCR4 virus or reemergence of initial infecting CCR5 virus. The hierarchical model pools partitions from multiple unrelated patients by assuming that the topology for each patient is drawn from a multinomial distribution with unknown probabilities. Preliminary results suggest evolution and not reemergence.", "title": "Hierarchical phylogenetic models for analyzing multipartite sequence data." } ]

[ { "docid": "3553087", "text": "Chronic obstructive pulmonary disease (COPD) is linked to both cigarette smoking and genetic determinants. We have previously identified iron-responsive element-binding protein 2 (IRP2) as an important COPD susceptibility gene and have shown that IRP2 protein is increased in the lungs of individuals with COPD. Here we demonstrate that mice deficient in Irp2 were protected from cigarette smoke (CS)-induced experimental COPD. By integrating RNA immunoprecipitation followed by sequencing (RIP-seq), RNA sequencing (RNA-seq), and gene expression and functional enrichment clustering analysis, we identified Irp2 as a regulator of mitochondrial function in the lungs of mice. Irp2 increased mitochondrial iron loading and levels of cytochrome c oxidase (COX), which led to mitochondrial dysfunction and subsequent experimental COPD. Frataxin-deficient mice, which had higher mitochondrial iron loading, showed impaired airway mucociliary clearance (MCC) and higher pulmonary inflammation at baseline, whereas mice deficient in the synthesis of cytochrome c oxidase, which have reduced COX, were protected from CS-induced pulmonary inflammation and impairment of MCC. Mice treated with a mitochondrial iron chelator or mice fed a low-iron diet were protected from CS-induced COPD. Mitochondrial iron chelation also alleviated CS-induced impairment of MCC, CS-induced pulmonary inflammation and CS-associated lung injury in mice with established COPD, suggesting a critical functional role and potential therapeutic intervention for the mitochondrial-iron axis in COPD.", "title": "Mitochondrial iron chelation ameliorates cigarette-smoke induced bronchitis and emphysema in mice" } ]

[ { "docid": "16120395", "text": "Tight regulation of the expression of mRNAs encoding iron uptake proteins is essential to control iron homeostasis and avoid intracellular iron toxicity. We show that many mRNAs encoding iron uptake or iron mobilization proteins are expressed in iron-replete conditions in the absence of the S. cerevisiae RNase III ortholog Rnt1p or of the nuclear exosome component Rrp6p. Extended forms of these mRNAs accumulate in the absence of Rnt1p or of the 5'-->3' exonucleases Xrn1p and Rat1p, showing that multiple degradative pathways contribute to the surveillance of aberrant forms of these transcripts. RNase III-deficient cells are hypersensitive to high iron concentrations, suggesting that Rnt1p-mediated RNA surveillance is required to prevent iron toxicity. These results show that RNA surveillance through multiple ribonucleolytic pathways plays a role in iron homeostasis in yeast to avoid the potentially toxic effects of the expression of the iron starvation response in iron-replete conditions.", "title": "Multiple RNA surveillance pathways limit aberrant expression of iron uptake mRNAs and prevent iron toxicity in S. cerevisiae." }, { "docid": "6828370", "text": "The canonical role of messenger RNA (mRNA) is to deliver protein-coding information to sites of protein synthesis. However, given that microRNAs bind to RNAs, we hypothesized that RNAs could possess a regulatory role that relies on their ability to compete for microRNA binding, independently of their protein-coding function. As a model for the protein-coding-independent role of RNAs, we describe the functional relationship between the mRNAs produced by the PTEN tumour suppressor gene and its pseudogene PTENP1 and the critical consequences of this interaction. We find that PTENP1 is biologically active as it can regulate cellular levels of PTEN and exert a growth-suppressive role. We also show that the PTENP1 locus is selectively lost in human cancer. We extended our analysis to other cancer-related genes that possess pseudogenes, such as oncogenic KRAS. We also demonstrate that the transcripts of protein-coding genes such as PTEN are biologically active. These findings attribute a novel biological role to expressed pseudogenes, as they can regulate coding gene expression, and reveal a non-coding function for mRNAs.", "title": "A coding-independent function of gene and pseudogene mRNAs regulates tumour biology" }, { "docid": "8496132", "text": "Overexpression of the proto-oncogene bcl-2 promotes abnormal cell survival by inhibiting apoptosis. Expression of bcl-2 is determined, in part, by regulatory mechanisms that control the stability of bcl-2 mRNA. Elements in the 3'-untranslated region of bcl-2 mRNA have been shown to play a role in regulating the stability of the message. Previously, it was found that the RNA binding proteins nucleolin and Ebp1 have a role in stabilizing bcl-2 mRNA in HL60 cells. Here, we have identified HuR as a component of bcl-2 messenger ribonucleoprotein (mRNP) complexes. RNA coimmunoprecipitation assays showed that HuR binds to bcl-2 mRNA in vivo. We also observed an RNA-dependent coprecipitation of HuR and nucleolin, suggesting that the two proteins are present in common mRNP complexes. Moreover, nucleolin and HuR bind concurrently to bcl-2 AU-rich element (ARE) RNA in vitro, suggesting separate binding sites for these proteins on bcl-2 mRNA. Knockdown of HuR in A431 cells leads to down-regulation of bcl-2 mRNA and protein levels. Observation of a decreased ratio of bcl-2 mRNA to heterogeneous nuclear RNA in HuR knockdown cells confirmed a positive role for HuR in regulating bcl-2 stability. Recombinant HuR retards exosome-mediated decay of bcl-2 ARE RNA in extracts of HL60 cells. This supports a role for HuR in the regulation of bcl-2 mRNA stability in HL60 cells, as well as in A431 cells. Addition of nucleolin and HuR to HL60 cell extracts produced a synergistic protective effect on decay of bcl-2 ARE RNA. HuR knockdown also leads to redistribution of bcl-2 mRNA from polysomes to monosomes. Thus, HuR seems to play a positive role in both regulation of bcl-2 mRNA translation and mRNA stability.", "title": "Regulation of Bcl-2 expression by HuR in HL60 leukemia cells and A431 carcinoma cells." }, { "docid": "12652963", "text": "MicroRNAs (miRNAs) are ∼22 nt non-coding RNAs that typically bind to the 3' UTR of target mRNAs in the cytoplasm, resulting in mRNA destabilization and translational repression. Here, we report that miRNAs can also regulate gene expression by targeting non-coding antisense transcripts in human cells. Specifically, we show that miR-671 directs cleavage of a circular antisense transcript of the Cerebellar Degeneration-Related protein 1 (CDR1) locus in an Ago2-slicer-dependent manner. The resulting downregulation of circular antisense has a concomitant decrease in CDR1 mRNA levels, independently of heterochromatin formation. This study provides the first evidence for non-coding antisense transcripts as functional miRNA targets, and a novel regulatory mechanism involving a positive correlation between mRNA and antisense circular RNA levels.", "title": "miRNA-dependent gene silencing involving Ago2-mediated cleavage of a circular antisense RNA." }, { "docid": "8698857", "text": "TNF expression of macrophages is under stringent translational control that depends on the p38 MAPK/MK2 pathway and the AU-rich element (ARE) in the TNF mRNA. Here, we elucidate the molecular mechanism of phosphorylation-regulated translation of TNF. We demonstrate that translation of the TNF-precursor at the ER requires expression of the ARE-binding and -stabilizing factor human antigen R (HuR) together with either activity of the p38 MAPK/MK2 pathway or the absence of the ARE-binding and -destabilizing factor tristetraprolin (TTP). We show that phosphorylation of TTP by MK2 decreases its affinity to the ARE, inhibits its ability to replace HuR, and permits HuR-mediated initiation of translation of TNF mRNA. Since translation of TTP's own mRNA is also regulated by this mechanism, an intrinsic feedback control of the inflammatory response is ensured. The phosphorylation-regulated TTP/HuR exchange at target mRNAs provides a reversible switch between unstable/non-translatable and stable/efficiently translated mRNAs.", "title": "The p38/MK2-Driven Exchange between Tristetraprolin and HuR Regulates AU–Rich Element–Dependent Translation" }, { "docid": "9301606", "text": "Parathyroid hormone (PTH), a major regulator of bone metabolism, activates the PTHR1 receptor on the osteoblast plasma membrane to initiate signaling and induce transcription of primary response genes. Subsequently, primary genes with transcriptional activity regulate expression of downstream PTH targets. We have identified the adenovirus E4 promoter-binding protein/nuclear factor regulated by IL-3 (E4bp4) as a PTH-induced primary gene in osteoblasts. E4BP4 is a basic leucine zipper (bZIP) transcription factor that represses or activates transcription in non-osteoblastic cells. We report here that PTH rapidly and transiently induced E4bp4 mRNA in osteoblastic cells and that this induction did not require protein synthesis. PTH also induced E4BP4 protein synthesis and E4BP4 binding to a consensus but not to a mutant E4BP4 response element (EBPRE). E4BP4 overexpression inhibited an EBPRE-containing promoter-reporter construct, whereas PTH treatment attenuated activity of the same construct in primary mouse osteoblasts. Finally, E4BP4 overexpression inhibited PTH-induced activity of a cyclooxygenase-2 promoter-reporter construct. Our data suggest a role for E4BP4 in attenuation of PTH target gene transcription in osteoblasts.", "title": "Parathyroid hormone-induced E4BP4/NFIL3 down-regulates transcription in osteoblasts." }, { "docid": "24221369", "text": "The cytosolic helicase retinoic acid-inducible gene-I (RIG-I) initiates immune responses to most RNA viruses by detecting viral 5'-triphosphorylated RNA (pppRNA). Although endogenous mRNA is also 5'-triphosphorylated, backbone modifications and the 5'-ppp-linked methylguanosine ((m7)G) cap prevent immunorecognition. Here we show that the methylation status of endogenous capped mRNA at the 5'-terminal nucleotide (N1) was crucial to prevent RIG-I activation. Moreover, we identified a single conserved amino acid (H830) in the RIG-I RNA binding pocket as the mediator of steric exclusion of N1-2'O-methylated RNA. H830A alteration (RIG-I(H830A)) restored binding of N1-2'O-methylated pppRNA. Consequently, endogenous mRNA activated the RIG-I(H830A) mutant but not wild-type RIG-I. Similarly, knockdown of the endogenous N1-2'O-methyltransferase led to considerable RIG-I stimulation in the absence of exogenous stimuli. Studies involving yellow-fever-virus-encoded 2'O-methyltransferase and RIG-I(H830A) revealed that viruses exploit this mechanism to escape RIG-I. Our data reveal a new role for cap N1-2'O-methylation in RIG-I tolerance of self-RNA.", "title": "A Conserved Histidine in the RNA Sensor RIG-I Controls Immune Tolerance to N1-2'O-Methylated Self RNA." }, { "docid": "21622715", "text": "Transcriptional factors binding to cAMP-responsive elements (CREs) in the promoters of various genes belong to the basic domain-leucine zipper superfamily and are composed of three genes in mammals, CREB, CREM, and ATF-1. A large number of CREB, CREM, and ATF-1 proteins are generated by posttranscriptional events, mostly alternative splicing, and regulate gene expression by acting as activators or repressors. Activation is classically brought about by signaling-dependent phosphorylation of a key acceptor site (Ser133 in CREB) by a number of possible kinases, including PKA, CamKIV, and Rsk-2. Phosphorylation is the prerequisite for the interaction of CBP (CREB-binding protein), a co-activator that has also histone acetyltransferase activity. Repression may involve dynamic dephosphorylation of the activators and thus decreased association with CBP. Another pathway of transcriptional repression on CRE sites implicates the inducible repressor ICER (inducible cAMP early repressor), a product of the CREM gene. Being an inducible repressor, ICER is involved in autoregulatory feedback loops of transcription that govern the down-regulation of early response genes, such as the proto-oncogene c-fos. The liver represents a remarkable physiological setting where cAMP-responsive signaling plays a major role. Indeed, a finely tuned program of gene expression is triggered by partial hepatectomy, so that through specific checkpoints a coordinated regeneration of the tissue is obtained. Temporal kinetics of transcriptional activation after hepatectomy reveals a pattern of early induction for several genes, some of them controlled by the CREB/CREM transcription factors. An important role of CREM in liver physiology was suggested by the robust induction of ICER after partial hepatectomy. The delay in tissue regeneration in CREM-deficient mice confirmed the important function of this factor in regulating hepatocyte proliferation. As gene induction is accompanied by critical changes in chromatin organization, the deciphering of the specific modification codes that histones display during liver regeneration and physiology will provide exciting new insights into the dynamics of chromatin architecture.", "title": "Coupling cAMP signaling to transcription in the liver: pivotal role of CREB and CREM." }, { "docid": "40721190", "text": "We have previously shown that YB-1 is the only protein of the HEK293 cell cytoplasmic (S100) extract that specifically interacts with RNA hairpins each containing one of the motifs ACCAGCCU (1), CAGUGAGC (2) and UAAUCCCA (3), which had been identified as often found in exosomal RNA and proposed as potential cis-acting elements targeting RNAs into exosomes. Here we explored the interactions of YB-1 with a fragment of the 3'-untranslated region (UTR) of septin 14 mRNA (SEPT14 RNA), which contains all three motifs. We demonstrated the occurrence of YB-1 among proteins pulled down from the HEK293 S100 extract using biotinylated SEPT14 RNA. With recombinant YB-1, it was found that SEPT14 RNA can bind up to 5 moles of protein per mole of RNA in a cooperative manner, which was shown to be mainly facilitated by the presence of the above motifs. RNA hairpins with motifs 1 and 2 competed with SEPT14 RNA for binding to the protein, whereas that with motif 3 was less competitive, in accordance with the affinity of YB-1 for these RNA hairpins. With YB-1-bound RNA, nucleotides protected from attack by hydroxyl radicals were revealed in all three motifs, although hairpins with motif 2 and especially with motif 1 contained many protected nucleotides outside the motifs, suggesting that the specific environments of these motifs contribute significantly to the YB-1 binding. An analysis of the environments of motifs 1-3 in the HEK293 cell mRNA 3' UTRs gained from RNA-seq data led us to conclude that the primary binding sites of YB-1 in the 3' UTRs are hairpins containing some part of the motif along with its specific surroundings; the consensus sequences of these hairpins were derived. Thus, our findings provide a new understanding of the structural basis of the interactions between YB-1 and mRNAs carrying the aforementioned motifs.", "title": "Structural features of the interaction of the 3'-untranslated region of mRNA containing exosomal RNA-specific motifs with YB-1, a potential mediator of mRNA sorting." }, { "docid": "7820043", "text": "The mitochondrial antiviral signaling protein (MAVS; also known as IPS-1, VISA, and CARDIF) is essential for innate immune response against RNA viruses. MAVS transduces signals from the cytosolic RIG-I-like receptors, which bind to viral RNAs. But how MAVS activates downstream transcription factors such as IRF3 to induce type-I interferons is not well understood. We have established a cell-free system in which mitochondria derived from virus-infected cells activate IRF3 in the cytosol. Fractionation of the cytosol led to the identification of Ubc5 as a ubiquitin-conjugating enzyme (E2) required for IRF3 activation. Using an inducible RNAi strategy, we demonstrate that catalytically active Ubc5 is required for IRF3 activation by viral infection. The activation of IRF3 also requires two ubiquitin-binding domains of NEMO. Furthermore, we show that replacement of endogenous ubiquitin with its K63R mutant abolishes viral activation of IRF3, demonstrating that K63 polyubiquitination plays a key role in IRF3 activation.", "title": "Key role of Ubc5 and lysine-63 polyubiquitination in viral activation of IRF3." }, { "docid": "13964633", "text": "BACKGROUND Mature microRNAs (miRNAs) are single-stranded RNAs that regulate post-transcriptional gene expression. In our previous study, we have shown that versican 3'UTR, a fragment of non-coding transcript, has the ability to antagonize miR-199a-3p function thereby regulating expression of the matrix proteins versican and fibronectin, and thus resulting in enhanced cell-cell adhesion and organ adhesion. However, the impact of this non-coding fragment on tumorigenesis is yet to be determined. \n METHODS AND FINDINGS Using computational prediction confirmed with in vitro and in vivo experiments, we report that the expression of versican 3'UTR not only antagonizes miR-199a-3p but can also lower its steady state expression. We found that expression of versican 3'UTR in a mouse breast carcinoma cell line, 4T1, decreased miR-199a-3p levels. The decrease in miRNA activity consequently translated into differences in tumor growth. Computational analysis indicated that both miR-199a-3p and miR-144 targeted a cell cycle regulator, Rb1. In addition, miR-144 and miR-136, which have also been shown to interact with versican 3'UTR, was found to target PTEN. Expression of Rb1 and PTEN were up-regulated synergistically in vitro and in vivo, suggesting that the 3'UTR binds and modulates miRNA activities, freeing Rb1 and PTEN mRNAs for translation. In tumor formation assays, cells transfected with the 3'UTR formed smaller tumors compared with cells transfected with a control vector. \n CONCLUSION Our results demonstrated that a 3'UTR fragment can be used to modulate miRNA functions. Our study also suggests that miRNAs in the cancer cells are more susceptible to degradation, due to its interaction with a non-coding 3'UTR. This non-coding component of mRNA may be used retrospectively to modulate miRNA activities.", "title": "Expression of Versican 3′-Untranslated Region Modulates Endogenous MicroRNA Functions" }, { "docid": "4465762", "text": "Transcription of eukaryotic protein-coding genes begins with assembly of the RNA polymerase (Pol) II initiation complex and promoter DNA opening. Here we report cryo-electron microscopy (cryo-EM) structures of yeast initiation complexes containing closed and open DNA at resolutions of 8.8 Å and 3.6 Å, respectively. DNA is positioned and retained over the Pol II cleft by a network of interactions between the TATA-box-binding protein TBP and transcription factors TFIIA, TFIIB, TFIIE, and TFIIF. DNA opening occurs around the tip of the Pol II clamp and the TFIIE ‘extended winged helix’ domain, and can occur in the absence of TFIIH. Loading of the DNA template strand into the active centre may be facilitated by movements of obstructing protein elements triggered by allosteric binding of the TFIIE ‘E-ribbon’ domain. The results suggest a unified model for transcription initiation with a key event, the trapping of open promoter DNA by extended protein–protein and protein–DNA contacts.", "title": "Transcription initiation complex structures elucidate DNA opening" }, { "docid": "9334631", "text": "OBJECTIVE C-Reactive protein (CRP), a cardiovascular risk marker, could also participate in atherosclerosis. Atherosclerotic plaques express CRP and interleukin (IL)-10, a major antiinflammatory cytokine. IL-10 deficiency results in increased lesion formation, whereas IL-10 delivery attenuates lesions. We tested the effect of CRP on lipopolysaccharide (LPS)-induced IL-10 secretion in human monocyte-derived macrophages (HMDMs). \n METHODS AND RESULTS Incubation of HMDMs with CRP significantly decreased LPS-induced IL-10 mRNA and intracellular and secreted IL-10 protein and destabilized IL-10 mRNA. Also, CRP alone increased secretion of IL-8, IL-6, and tumor necrosis factor from HMDMs and did not inhibit LPS-induced secretion of these cytokines. Fc gamma receptor I antibodies significantly reversed CRP-mediated IL-10 inhibition. CRP significantly decreased intracellular cAMP, phospho-cAMP response element binding protein (pCREB), and adenyl cyclase activity. cAMP agonists reversed CRP-mediated IL-10 inhibition. Overexpression of wild-type and constitutively active CREB in THP-1 cells revealed attenuation of the inhibitory effect of CRP on LPS-induced IL-10 levels. CRP also inhibited hemoglobin:haptoglobin-induced IL-10 and heme oxygenase-1. Furthermore, administration of human CRP to rats significantly decreased IL-10 levels. \n CONCLUSIONS This study provides novel evidence that CRP, by decreasing IL-10 alters the antiinflammatory/proinflammatory balance, accentuating inflammation, which is pivotal in atherothrombosis.", "title": "C-reactive protein decreases interleukin-10 secretion in activated human monocyte-derived macrophages via inhibition of cyclic AMP production." }, { "docid": "984825", "text": "Post-transcriptional modification of RNA nucleosides occurs in all living organisms. Pseudouridine, the most abundant modified nucleoside in non-coding RNAs, enhances the function of transfer RNA and ribosomal RNA by stabilizing the RNA structure. Messenger RNAs were not known to contain pseudouridine, but artificial pseudouridylation dramatically affects mRNA function--it changes the genetic code by facilitating non-canonical base pairing in the ribosome decoding centre. However, without evidence of naturally occurring mRNA pseudouridylation, its physiological relevance was unclear. Here we present a comprehensive analysis of pseudouridylation in Saccharomyces cerevisiae and human RNAs using Pseudo-seq, a genome-wide, single-nucleotide-resolution method for pseudouridine identification. Pseudo-seq accurately identifies known modification sites as well as many novel sites in non-coding RNAs, and reveals hundreds of pseudouridylated sites in mRNAs. Genetic analysis allowed us to assign most of the new modification sites to one of seven conserved pseudouridine synthases, Pus1-4, 6, 7 and 9. Notably, the majority of pseudouridines in mRNA are regulated in response to environmental signals, such as nutrient deprivation in yeast and serum starvation in human cells. These results suggest a mechanism for the rapid and regulated rewiring of the genetic code through inducible mRNA modifications. Our findings reveal unanticipated roles for pseudouridylation and provide a resource for identifying the targets of pseudouridine synthases implicated in human disease.", "title": "Pseudouridine profiling reveals regulated mRNA pseudouridylation in yeast and human cells" }, { "docid": "40044800", "text": "The presence of DNA in the cytoplasm of mammalian cells is a danger signal that triggers host immune responses such as the production of type I interferons. Cytosolic DNA induces interferons through the production of cyclic guanosine monophosphate-adenosine monophosphate (cyclic GMP-AMP, or cGAMP), which binds to and activates the adaptor protein STING. Through biochemical fractionation and quantitative mass spectrometry, we identified a cGAMP synthase (cGAS), which belongs to the nucleotidyltransferase family. Overexpression of cGAS activated the transcription factor IRF3 and induced interferon-β in a STING-dependent manner. Knockdown of cGAS inhibited IRF3 activation and interferon-β induction by DNA transfection or DNA virus infection. cGAS bound to DNA in the cytoplasm and catalyzed cGAMP synthesis. These results indicate that cGAS is a cytosolic DNA sensor that induces interferons by producing the second messenger cGAMP.", "title": "Cyclic GMP-AMP synthase is a cytosolic DNA sensor that activates the type I interferon pathway." }, { "docid": "30297355", "text": "The Norrie disease gene (Ndp) codes for a secreted protein, Norrin, that activates canonical Wnt signaling by binding to its receptor, Frizzled-4. This signaling system is required for normal vascular development in the retina and for vascular survival in the cochlea. In mammals, the pattern of Ndp expression beyond the retina is poorly defined due to the low abundance of Norrin mRNA and protein. Here, we characterize Ndp expression during mouse development by studying a knock-in mouse that carries the coding sequence of human placental alkaline phosphatase (AP) inserted at the Ndp locus (Ndp(AP)). In the CNS, Ndp(AP) expression is apparent by E10.5 and is dynamic and complex. The anatomically delimited regions of Ndp(AP) expression observed prenatally in the CNS are replaced postnatally by widespread expression in astrocytes in the forebrain and midbrain, Bergman glia in the cerebellum, and Müller glia in the retina. In the developing and adult cochlea, Ndp(AP) expression is closely associated with two densely vascularized regions, the stria vascularis and a capillary plexus between the organ of Corti and the spiral ganglion. These observations suggest the possibility that Norrin may have developmental and/or homeostatic functions beyond the retina and cochlea.", "title": "Expression of the Norrie disease gene (Ndp) in developing and adult mouse eye, ear, and brain." }, { "docid": "25830701", "text": "The cytokine erythropoietin (Epo) promotes erythropoietic progenitor cell proliferation and is required for erythropoietic differentiation. We have found that the Epo gene is a direct transcriptional target gene of retinoic acid signaling during early erythropoiesis (prior to embryonic day E12.5) in the fetal liver. Mouse embryos lacking the retinoic acid receptor gene RXR alpha have a morphological and histological phenotype that is comparable with embryos in which the Epo gene itself has been mutated, and flow cytometric analysis indicates that RXR alpha-deficient embryos are deficient in erythroid differentiation. Epo mRNA levels are reduced substantially in the fetal livers of RXR alpha(-/-) embryos at E10.25 and E11.25, and genetic analysis shows that the RXR alpha and Epo genes are coupled in the same pathway. We furthermore show that the Epo gene is retinoic acid inducible in embryos, and that the Epo gene enhancer contains a DR2 sequence that represents a retinoic acid receptor-binding site and a retinoic acid receptor transcriptional response element. However, unlike Epo-deficient embryos that die from anemia, the erythropoietic deficiency in RXR alpha(-/-) embryos is transient; Epo mRNA is expressed at normal levels by E12.5, and erythropoiesis and liver morphology are normal by E14.5. We show that HNF4, like RXR alpha a member of the nuclear receptor family, is abundantly expressed in fetal liver hepatocytes, and is competitive with retinoic acid receptors for occupancy of the Epo gene enhancer DR2 element. We propose that Epo expression is regulated during the E9.5--E11.5 phase of fetal liver erythropoiesis by RXR alpha and retinoic acid, and that expression then becomes dominated by HNF4 activity from E11.5 onward. This transition may be responsible for switching regulation of Epo expression from retinoic acid control to hypoxic control, as is found throughout the remainder of life.", "title": "A developmental transition in definitive erythropoiesis: erythropoietin expression is sequentially regulated by retinoic acid receptors and HNF4." }, { "docid": "25682129", "text": "The sequence-specific binding to DNA is crucial for the p53 tumor suppressor function. To investigate the constraints imposed on p53-DNA recognition by nucleosomal organization, we studied binding of the p53 DNA binding domain (p53DBD) and full-length wild-type p53 protein to a single p53 response element (p53RE) placed near the nucleosomal dyad in six rotational settings. We demonstrate that the strongest p53 binding occurs when the p53RE in the nucleosome is bent in the same direction as observed for the p53-DNA complexes in solution and in co-crystals. The p53RE becomes inaccessible, however, if its orientation in the core particle is changed by approximately 180 degrees. Our observations indicate that the orientation of the binding sites on a nucleosome may play a significant role in the initial p53-DNA recognition and subsequent cofactor recruitment.", "title": "p53 binding to nucleosomal DNA depends on the rotational positioning of DNA response element." }, { "docid": "7970974", "text": "Identifying genomic elements required for viability is central to our understanding of the basic physiology of bacterial pathogens. Recently, the combination of high-density mutagenesis and deep sequencing has allowed for the identification of required and conditionally required genes in many bacteria. Genes, however, make up only a part of the complex genomes of important bacterial pathogens. Here, we use an unbiased analysis to comprehensively identify genomic regions, including genes, domains, and intergenic elements, required for the optimal growth of Mycobacterium tuberculosis, a major global health pathogen. We found that several proteins jointly contain both domains required for optimal growth and domains that are dispensable. In addition, many non-coding regions, including regulatory elements and non-coding RNAs, are critical for mycobacterial growth. Our analysis shows that the genetic requirements for growth are more complex than can be appreciated using gene-centric analysis.", "title": "Global Assessment of Genomic Regions Required for Growth in Mycobacterium tuberculosis" } ]

[ { "docid": "14797520", "text": "Nuclear transcription is not restricted to genes but occurs throughout the intergenic and noncoding space of eukaryotic genomes. The functional significance of this widespread noncoding transcription is mostly unknown. We show that Arabidopsis RNA polymerase IVb/Pol V, a multisubunit nuclear enzyme required for siRNA-mediated gene silencing of transposons and other repeats, transcribes intergenic and noncoding sequences, thereby facilitating heterochromatin formation and silencing of overlapping and adjacent genes. Pol IVb/Pol V transcription requires the chromatin-remodeling protein DRD1 but is independent of siRNA biogenesis. However, Pol IVb/Pol V transcription and siRNA production are both required to silence transposons, suggesting that Pol IVb/Pol V generates RNAs or chromatin structures that serve as scaffolds for siRNA-mediated heterochromatin-forming complexes. Pol IVb/Pol V function provides a solution to a paradox of epigenetic control: the need for transcription in order to transcriptionally silence the same region.", "title": "Noncoding Transcription by RNA Polymerase Pol IVb/Pol V Mediates Transcriptional Silencing of Overlapping and Adjacent Genes" } ]

[ { "docid": "32275758", "text": "DNA polymerases mu (pol mu), lambda (pol lambda), and terminal deoxynucleotidyltransferase (TdT) are enzymes of the pol X family that share homology in sequence and functional domain organization. We showed previously that pol mu participates in light chain but surprisingly not heavy chain gene rearrangement. We show here that immunoglobulin heavy chain junctions from pol lambda-deficient animals have shorter length with normal N-additions, thus indicating that pol lambda is recruited during heavy chain rearrangement at a step that precedes the action of TdT. In contrast to previous in vitro studies, analysis of animals with combined inactivation of these enzymes revealed no overlapping or compensatory activities for V(D)J recombination between pol mu, pol lambda, and TdT. This complex usage of polymerases with distinct catalytic specificities may correspond to the specific function that the third hypervariable region assumes for each immunoglobulin chain, with pol lambda maintaining a large heavy chain junctional heterogeneity and pol mu ensuring a restricted light chain junctional variability.", "title": "Nonoverlapping functions of DNA polymerases mu, lambda, and terminal deoxynucleotidyltransferase during immunoglobulin V(D)J recombination in vivo." }, { "docid": "34559336", "text": "Three Pol X family members have been linked to nonhomologous end joining (NHEJ) in mammals. Template-independent TdT promotes diversity during NHEJ-dependent repair of V(D)J recombination intermediates, but the roles of the template-dependent polymerases mu and lambda in NHEJ remain unclear. We show here that pol mu and pol lambda are similarly recruited by NHEJ factors to fill gaps when ends have partially complementary overhangs, suggesting equivalent roles promoting accuracy in NHEJ. However, only pol mu promotes accuracy during immunoglobulin kappa recombination. This distinctive in vivo role correlates with the TdT-like ability of pol mu, but not pol lambda, to act when primer termini lack complementary bases in the template strand. However, unlike TdT, synthesis by pol mu in this context is primarily instructed by a template from another DNA molecule. This apparent gradient of template dependence is largely attributable to a small structural element that is present but different in all three polymerases.", "title": "A gradient of template dependence defines distinct biological roles for family X polymerases in nonhomologous end joining." }, { "docid": "13072112", "text": "A number of proteins and drugs have been implicated in the process of transcriptional elongation by RNA polymerase (Pol) II, but the factors that govern the elongation rate (nucleotide additions per min) and processivity (nucleotide additions per initiation event) in vivo are poorly understood. Here, we show that a mutation in the Rpb2 subunit of Pol II reduces both the elongation rate and processivity in vivo. In contrast, none of the putative elongation factors tested affect the elongation rate, although mutations in the THO complex and in Spt4 significantly reduce processivity. The drugs 6-azauracil and mycophenolic acid reduce both the elongation rate and processivity, and this processivity defect is aggravated by mutations in Spt4, TFIIS, and CTDK-1. Our results suggest that, in vivo, a reduced rate of Pol II elongation leads to premature dissociation along the chromatin template and that Pol II processivity can be uncoupled from elongation rate.", "title": "Distinction and relationship between elongation rate and processivity of RNA polymerase II in vivo." }, { "docid": "14380875", "text": "Glucocorticoids repress NFkappaB-mediated activation of proinflammatory genes such as interleukin-8 (IL-8) and ICAM-1. Our experiments suggest that the glucocorticoid receptor (GR) confers this effect by associating through protein-protein interactions with NFkappaB bound at each of these genes. That is, we show that the GR zinc binding region (ZBR), which includes the DNA binding and dimerization functions of the receptor, binds directly to the dimerization domain of the RelA subunit of NFkappaB in vitro and that the ZBR is sufficient to associate with RelA bound at NFkappaB response elements in vivo. Moreover, we demonstrate in vivo and in vitro that GR does not disrupt DNA binding by NFkappaB. In transient transfections, we found that the GR ligand binding domain is essential for repression of NFkappaB but not for association with it and that GR can repress an NFkappaB derivative bearing a heterologous activation domain. We used chromatin immunoprecipitation assays in untransfected A549 cells to infer the mechanism by which the tethered GR represses NFkappaB-activated transcription. As expected, we found that the inflammatory signal TNFalpha stimulated preinitiation complex (PIC) assembly at the IL-8 and ICAM-1 promoters and that the largest subunit of RNA polymerase II (pol II) in those complexes became phosphorylated at serines 2 and 5 in its carboxy-terminal domain (CTD) heptapeptide repeats (YSPTSPS); these modifications are required for transcription initiation. Remarkably, GR did not inhibit PIC assembly under repressing conditions, but rather interfered with phosphorylation of serine 2 of the pol II CTD.", "title": "The Glucocorticoid Receptor Inhibits" }, { "docid": "6670101", "text": "It is long been known that cancer and non-cancer cells can be distinguished on the basis of their nucleolar morphologies. As early as the 19th century, it was reported that cancer cells have larger and more irregularly shaped nucleoli. Since then, pathologists have used nucleolar morphology to predict the clinical outcome [1]. Nucleolar morphology is altered due to the up-regulation of ribosomal gene transcription. Within nucleoli, ribosomal genes (rDNA) are transcribed by RNA polymerase I (pol I). The pre-ribosomal RNA (pre-rRNA) transcripts are subsequently modified and processed into the mature 18S, 5.8S and 28S rRNAs. 5S rRNA is transcribed by RNA polymerase III in the nucleoplasm. Together with the ribosomal proteins, the 5S rRNA is imported into the nucleolus where 40S and 60S ribosomal subunits are assembled prior to export to the cytoplasm [1, 2]. Oncogenes such as c-Myc can both directly and indirectly upregulate rDNA transcription, while tumour suppressors like p53 and Rb suppress ribosome biogenesis. Mutations in these genes not only result in deregulated cell cycle control, but also upregulated ribosome biogenesis. In addition to ribosome biogenesis, the nucleolus is a key cellular stress sensor and plays a central role in p53 activation [1, 2]. The increased translational capacity of cancer cells enables them to maintain higher proliferation rates. As stated by Ruggero, “compared with normal cells, cancer cells may be addicted to increases in ribosome biogenesis and number” [1]. This provides new therapeutic opportunities. As it turns out many chemotherapeutic drugs used in cancer treatment already inhibit ribosome biogenesis. In one recent survey it was shown that 20 out of 36 drugs in clinical use inhibit ribosome biogenesis [3]. Most of these drugs were originally designed to target highly proliferating cells by damaging DNA, interfering with DNA synthesis or with mitosis. These targeting modalities of these drugs also lead to toxicity in normal highly proliferating tissues. An example is ActinomycinD (AMD), a DNA intercalator which has a preference for GC-rich DNA sequences. As rDNA has above average GC-richness and because of its open chromatin conformation, low concentrations of AMD preferentially inhibit RNA polymerase I transcription and upon prolonged exposure causes genome wide DNA damage. Alkylating drugs like cisplatin and oxaliplatin or topoisomerases poisons like camptothecin inhibit pol I transcription. The degree to which inhibition of ribosome biogenesis contributes to the efficacy of these drugs is difficult to establish [3]. This raises an important question. Can targeting ribosome biogenesis without DNA damage offer any therapeutic potential? Two recently described drugs CX-5461 and BMH-21 are now providing evidence that inhibition of ribosome biogenesis by targeting transcription of rDNA by pol I has promising therapeutic potential. CX-5461 was designed to specifically inhibit pol I transcription by disrupting pre-initiation complex formation at the rDNA promoter. CX-5461 has been shown to activate p53 via nucleolar stress. It induces autophagy as well as senescence in a multiple types of cancer cells in a p53-dependent manner. Especially in leukaemia and lymphoma cells, treatment with CX-5461 induces p53-dependent apoptosis, while normal cells tolerate it [4, 5]. Whether the drug also induces DNA damage was not fully addressed, but it was demonstrated that it could induce cell death in cells lacking ATM - a key mediator of DNA double strand break responses. However, more recently Laiho and colleagues have shown that at high concentrations, CX-5461 does induce a γH2AX response, raising concerns about DNA damage [6]. BMH-21 was identified in a screen performed by Laiho and colleagues aimed at identifying novel p53 activators. Like AMD, BMH-21 is a DNA intercalator with preference for GC rich sequences [7]. Continuing the parallel with AMD, BMH-21 is a potent and specific inhibitor rDNA transcription and induces nucleolar reorganisation often referred to as nucleolar capping. Interestingly, transcription inhibition was followed by the degradation of the main pol I subunit, RPA194, by the proteasome [6]. In contrast with AMD, initial indications were that BMH-21 did not appear to induce DNA damage as evidenced by the lack of a γH2AX response [7]. Inhibition of transcription by BMH-21 causes nucleolar stress, resulting in decreased proliferation and cell death. P53 is activated in BMH-21 treated cells but is not required for its anti-proliferative effects. Intriguingly, it appears that cancer cells with high demands for ribosome biogenesis are selectively targeted [6]. The current publication in Oncotarget now rules out any role for DNA damage signalling and repair pathways in the BMH-21 response. Moreover, BMH-21 derivatives that can induce DNA damage display lower efficiency in inducing nucleolar stress and inhibiting proliferation [8]. The central importance of this study is that it finally uncouples DNA damage and nucleolar stress and reveals an Achilles heel in cancer cells, their addiction to ribosome biogenesis.", "title": "Ribosome biogenesis: Achilles heel of cancer?" }, { "docid": "29788648", "text": "NuA4, the major H4 lysine acetyltransferase (KAT) complex in Saccharomyces cerevisiae, is recruited to promoters and stimulates transcription initiation. NuA4 subunits contain domains that bind methylated histones, suggesting that histone methylation should target NuA4 to coding sequences during transcription elongation. We show that NuA4 is cotranscriptionally recruited, dependent on its physical association with elongating polymerase II (Pol II) phosphorylated on the C-terminal domain by cyclin-dependent kinase 7/Kin28, but independently of subunits (Eaf1 and Tra1) required for NuA4 recruitment to promoters. Whereas histone methylation by Set1 and Set2 is dispensable for NuA4's interaction with Pol II and targeting to some coding regions, it stimulates NuA4-histone interaction and H4 acetylation in vivo. The NuA4 KAT, Esa1, mediates increased H4 acetylation and enhanced RSC occupancy and histone eviction in coding sequences and stimulates the rate of transcription elongation. Esa1 cooperates with the H3 KAT in SAGA, Gcn5, to enhance these functions. Our findings delineate a pathway for acetylation-mediated nucleosome remodeling and eviction in coding sequences that stimulates transcription elongation by Pol II in vivo.", "title": "NuA4 lysine acetyltransferase Esa1 is targeted to coding regions and stimulates transcription elongation with Gcn5." }, { "docid": "4465762", "text": "Transcription of eukaryotic protein-coding genes begins with assembly of the RNA polymerase (Pol) II initiation complex and promoter DNA opening. Here we report cryo-electron microscopy (cryo-EM) structures of yeast initiation complexes containing closed and open DNA at resolutions of 8.8 Å and 3.6 Å, respectively. DNA is positioned and retained over the Pol II cleft by a network of interactions between the TATA-box-binding protein TBP and transcription factors TFIIA, TFIIB, TFIIE, and TFIIF. DNA opening occurs around the tip of the Pol II clamp and the TFIIE ‘extended winged helix’ domain, and can occur in the absence of TFIIH. Loading of the DNA template strand into the active centre may be facilitated by movements of obstructing protein elements triggered by allosteric binding of the TFIIE ‘E-ribbon’ domain. The results suggest a unified model for transcription initiation with a key event, the trapping of open promoter DNA by extended protein–protein and protein–DNA contacts.", "title": "Transcription initiation complex structures elucidate DNA opening" }, { "docid": "7416873", "text": "Interphase nuclear repositioning of chromosomes has been implicated in the epigenetic regulation of RNA polymerase (pol) II transcription. However, little is known about the nuclear position–dependent regulation of RNA pol I–transcribed loci. Trypanosoma brucei is an excellent model system to address this question because its two main surface protein genes, procyclin and variant surface glycoprotein (VSG), are transcribed by pol I and undergo distinct transcriptional activation or downregulation events during developmental differentiation. Although the monoallelically expressed VSG locus is exclusively localized to an extranucleolar body in the bloodstream form, in this study, we report that nonmutually exclusive procyclin genes are located at the nucleolar periphery. Interestingly, ribosomal DNA loci and pol I transcription activity are restricted to similar perinucleolar positions. Upon developmental transcriptional downregulation, however, the active VSG promoter selectively undergoes a rapid and dramatic repositioning to the nuclear envelope. Subsequently, the VSG promoter region was subjected to chromatin condensation. We propose a model whereby the VSG expression site pol I promoter is selectively targeted by temporal nuclear repositioning during developmental silencing.", "title": "Nuclear repositioning of the VSG promoter during developmental silencing in Trypanosoma brucei" }, { "docid": "12149169", "text": "Synthesis of ribosomal RNA (rRNA) by RNA polymerase (Pol) I is the first step in ribosome biogenesis and a regulatory switch in eukaryotic cell growth. Here we report the 12 A cryo-electron microscopic structure for the complete 14-subunit yeast Pol I, a homology model for the core enzyme, and the crystal structure of the subcomplex A14/43. In the resulting hybrid structure of Pol I, A14/43, the clamp, and the dock domain contribute to a unique surface interacting with promoter-specific initiation factors. The Pol I-specific subunits A49 and A34.5 form a heterodimer near the enzyme funnel that acts as a built-in elongation factor and is related to the Pol II-associated factor TFIIF. In contrast to Pol II, Pol I has a strong intrinsic 3'-RNA cleavage activity, which requires the C-terminal domain of subunit A12.2 and, apparently, enables ribosomal RNA proofreading and 3'-end trimming.", "title": "Functional Architecture of RNA Polymerase I" }, { "docid": "1354567", "text": "In Arabidopsis thaliana, small interfering RNAs (siRNAs) direct cytosine methylation at endogenous DNA repeats in a pathway involving two forms of nuclear RNA polymerase IV (Pol IVa and Pol IVb), RNA-DEPENDENT RNA POLYMERASE 2 (RDR2), DICER-LIKE 3 (DCL3), ARGONAUTE4 (AGO4), the chromatin remodeler DRD1, and the de novo cytosine methyltransferase DRM2. We show that RDR2, DCL3, AGO4, and NRPD1b (the largest subunit of Pol IVb) colocalize with siRNAs within the nucleolus. By contrast, Pol IVa and DRD1 are external to the nucleolus and colocalize with endogenous repeat loci. Mutation-induced loss of pathway proteins causes downstream proteins to mislocalize, revealing their order of action. Pol IVa acts first, and its localization is RNA dependent, suggesting an RNA template. We hypothesize that maintenance of the heterochromatic state involves locus-specific Pol IVa transcription followed by siRNA production and assembly of AGO4- and NRPD1b-containing silencing complexes within nucleolar processing centers.", "title": "The Arabidopsis Chromatin-Modifying Nuclear siRNA Pathway Involves a Nucleolar RNA Processing Center" }, { "docid": "25175223", "text": "RNA polymerase II is implicated in the RNA-templated RNA synthesis during replication of viroids and Hepatitis Delta Virus (HDV); however, neither the RNA template nor protein factor requirements for this process are well defined. We have developed an in vitro transcription system based on HeLa cell nuclear extract (NE), in which a segment of antigenomic RNA corresponding to the left-hand tip region of the HDV rod-like structure serves as a template for efficient and highly specific RNA synthesis. Accumulation of the unique RNA product is highly sensitive to alpha-amanitin in HeLa NE and only partially sensitive to this drug in NE from PMG cells that contain an allele of the alpha-amanitin-resistant subunit of pol II, strongly suggesting pol II involvement in this reaction. Detailed analysis of the RNA product revealed that it represents a chimeric molecule composed of a newly synthesized transcript covalently attached to the 5' half of the RNA template. Selection of the start site for transcription is remarkably specific and depends on the secondary structure of the RNA template, rather than on its primary sequence. Some features of this reaction resemble the RNA cleavage-extension process observed for pol II-arrested complexes in vitro. A possible involvement of the described reaction in HDV replication is discussed.", "title": "Specific HDV RNA-templated transcription by pol II in vitro." }, { "docid": "4162857", "text": "RNA processing is carried out in close proximity to the site of transcription, suggesting a regulatory link between transcription and pre-mRNA splicing. Using an in vitro transcription/splicing assay, we demonstrate that an association of RNA polymerase II (Pol II) transcription and pre-mRNA splicing is required for efficient gene expression. Pol II-synthesized RNAs containing functional splice sites are protected from nuclear degradation, presumably because the local concentration of the splicing machinery is sufficiently high to ensure its association over interactions with nucleases. Furthermore, the process of transcription influences alternative splicing of newly synthesized pre-mRNAs. Because other RNA polymerases do not provide similar protection from nucleases, and their RNA products display altered splicing patterns, the link between transcription and RNA processing is RNA Pol II-specific. We propose that the connection between transcription by Pol II and pre-mRNA splicing guarantees an extended half-life and proper processing of nascent pre-mRNAs.", "title": "Linking Splicing to Pol II Transcription Stabilizes Pre-mRNAs and Influences Splicing Patterns" }, { "docid": "4393153", "text": "RNA polymerase (Pol) II catalyses DNA-dependent RNA synthesis during gene transcription. There is, however, evidence that Pol II also possesses RNA-dependent RNA polymerase (RdRP) activity. Pol II can use a homopolymeric RNA template, can extend RNA by several nucleotides in the absence of DNA, and has been implicated in the replication of the RNA genomes of hepatitis delta virus (HDV) and plant viroids. Here we show the intrinsic RdRP activity of Pol II with only pure polymerase, an RNA template–product scaffold and nucleoside triphosphates (NTPs). Crystallography reveals the template–product duplex in the site occupied by the DNA–RNA hybrid during transcription. RdRP activity resides at the active site used during transcription, but it is slower and less processive than DNA-dependent activity. RdRP activity is also obtained with part of the HDV antigenome. The complex of transcription factor IIS (TFIIS) with Pol II can cleave one HDV strand, create a reactive stem-loop in the hybrid site, and extend the new RNA 3′ end. Short RNA stem-loops with a 5′ extension suffice for activity, but their growth to a critical length apparently impairs processivity. The RdRP activity of Pol II provides a missing link in molecular evolution, because it suggests that Pol II evolved from an ancient replicase that duplicated RNA genomes.", "title": "Molecular basis of RNA-dependent RNA polymerase II activity" }, { "docid": "25186412", "text": "The PANTHER (protein annotation through evolutionary relationship) classification system (http://www.pantherdb.org/) is a comprehensive system that combines gene function, ontology, pathways and statistical analysis tools that enable biologists to analyze large-scale, genome-wide data from sequencing, proteomics or gene expression experiments. The system is built with 82 complete genomes organized into gene families and subfamilies, and their evolutionary relationships are captured in phylogenetic trees, multiple sequence alignments and statistical models (hidden Markov models or HMMs). Genes are classified according to their function in several different ways: families and subfamilies are annotated with ontology terms (Gene Ontology (GO) and PANTHER protein class), and sequences are assigned to PANTHER pathways. The PANTHER website includes a suite of tools that enable users to browse and query gene functions, and to analyze large-scale experimental data with a number of statistical tests. It is widely used by bench scientists, bioinformaticians, computer scientists and systems biologists. In the 2013 release of PANTHER (v.8.0), in addition to an update of the data content, we redesigned the website interface to improve both user experience and the system's analytical capability. This protocol provides a detailed description of how to analyze genome-wide experimental data with the PANTHER classification system.", "title": "Large-scale gene function analysis with the PANTHER classification system" }, { "docid": "3847200", "text": "Direct induction of induced hepatocytes (iHeps) from fibroblasts holds potential as a strategy for regenerative medicine but until now has only been shown in culture settings. Here, we describe in vivo iHep formation using transcription factor induction and genetic fate tracing in mouse models of chronic liver disease. We show that ectopic expression of the transcription factors FOXA3, GATA4, HNF1A, and HNF4A from a polycistronic lentiviral vector converts mouse myofibroblasts into cells with a hepatocyte phenotype. In vivo expression of the same set of transcription factors from a p75 neurotrophin receptor peptide (p75NTRp)-tagged adenovirus enabled the generation of hepatocyte-like cells from myofibroblasts in fibrotic mouse livers and reduced liver fibrosis. We have therefore been able to convert pro-fibrogenic myofibroblasts in the liver into hepatocyte-like cells with positive functional benefits. This direct in vivo reprogramming approach may open new avenues for the treatment of chronic liver disease.", "title": "Direct Reprogramming of Hepatic Myofibroblasts into Hepatocytes In Vivo Attenuates Liver Fibrosis." }, { "docid": "27635177", "text": "Mammalian DNA polymerase mu (pol mu) is related to terminal deoxynucleotidyl transferase, but its biological role is not yet clear. We show here that after exposure of cells to ionizing radiation (IR), levels of pol mu protein increase. pol mu also forms discrete nuclear foci after IR, and these foci are largely coincident with IR-induced foci of gammaH2AX, a previously characterized marker of sites of DNA double-strand breaks. pol mu is thus part of the cellular response to DNA double-strand breaks. pol mu also associates in cell extracts with the nonhomologous end-joining repair factor Ku and requires both Ku and another end-joining factor, XRCC4-ligase IV, to form a stable complex on DNA in vitro. pol mu in turn facilitates both stable recruitment of XRCC4-ligase IV to Ku-bound DNA and ligase IV-dependent end joining. In contrast, the related mammalian DNA polymerase beta does not form a complex with Ku and XRCC4-ligase IV and is less effective than pol mu in facilitating joining mediated by these factors. Our data thus support an important role for pol mu in the end-joining pathway for repair of double-strand breaks.", "title": "Association of DNA polymerase mu (pol mu) with Ku and ligase IV: role for pol mu in end-joining double-strand break repair." }, { "docid": "41852733", "text": "Ehlers-Danlos syndrome (EDS) type I (the classical variety) is a dominantly inherited, genetically heterogeneous connective-tissue disorder. Mutations in the COL5A1 and COL5A2 genes, which encode type V collagen, have been identified in several individuals. Most mutations affect either the triple-helical domain of the protein or the expression of one COL5A1 allele. We identified a novel splice-acceptor mutation (IVS4-2A-->G) in the N-propeptide-encoding region of COL5A1, in one patient with EDS type I. The outcome of this mutation was complex: In the major product, both exons 5 and 6 were skipped; other products included a small amount in which only exon 5 was skipped and an even smaller amount in which cryptic acceptor sites within exon 5 were used. All products were in frame. Pro-alpha1(V) chains with abnormal N-propeptides were secreted and were incorporated into extracellular matrix, and the mutation resulted in dramatic alterations in collagen fibril structure. The two-exon skip occurred in transcripts in which intron 5 was removed rapidly relative to introns 4 and 6, leaving a large (270 nt) composite exon that can be skipped in its entirety. The transcripts in which only exon 5 was skipped were derived from those in which intron 6 was removed prior to intron 5. The use of cryptic acceptor sites in exon 5 occurred in transcripts in which intron 4 was removed subsequent to introns 5 and 6. These findings suggest that the order of intron removal plays an important role in the outcome of splice-site mutations and provide a model that explains why multiple products derive from a mutation at a single splice site.", "title": "Order of intron removal influences multiple splice outcomes, including a two-exon skip, in a COL5A1 acceptor-site mutation that results in abnormal pro-alpha1(V) N-propeptides and Ehlers-Danlos syndrome type I." }, { "docid": "1782201", "text": "Integrins regulate adhesion-dependent growth, survival and invasion of tumor cells. In particular, expression of integrin alpha(v)beta(3) is associated with progression of a variety of human tumors. Here we reveal a previously undescribed adhesion-independent role for integrin alpha(v)beta(3) in pancreatic cancer and other carcinomas. Specifically, alpha(v)beta(3) expressed in carcinoma cells enhanced anchorage-independent tumor growth in vitro and increased lymph node metastases in vivo. These effects required recruitment of c-Src to the beta(3) integrin cytoplasmic tail, leading to c-Src activation, Crk-associated substrate (CAS) phosphorylation and tumor cell survival that, unexpectedly, was independent of cell adhesion or focal adhesion kinase (FAK) activation. Pharmacological blockade of c-Src kinase activity or decreased expression of endogenous alpha(v)beta(3) integrin or c-Src not only inhibited anchorage-independent growth but also suppressed metastasis in vivo, yet these manipulations did not affect tumor cell migration or invasion. These data define an unexpected role for an integrin as a mediator of anchorage independence, suggesting that an alpha(v)beta(3)-c-Src signaling module may account for the aggressive behavior of integrin alpha(v)beta(3)-expressing tumors in humans.", "title": "Integrin αvβ3/c-src “Oncogenic Unit” Promotes Anchorage-independence and Tumor Progression" }, { "docid": "26899920", "text": "It was recently shown that mouse fibroblasts could be reprogrammed into cells of a cardiac fate by forced expression of multiple transcription factors and microRNAs. For ultimate application of such a reprogramming strategy for cell-based therapy or in vivo cardiac regeneration, reducing or eliminating the genetic manipulations by small molecules would be highly desirable. Here, we report the identification of a defined small-molecule cocktail that enables the highly efficient conversion of mouse fibroblasts into cardiac cells with only one transcription factor, Oct4, without any evidence of entrance into the pluripotent state. Small-molecule-induced cardiomyocytes spontaneously contract and exhibit a ventricular phenotype. Furthermore, these induced cardiomyocytes pass through a cardiac progenitor stage. This study lays the foundation for future pharmacological reprogramming approaches and provides a small-molecule condition for investigation of the mechanisms underlying the cardiac reprogramming process.", "title": "Small molecules enable cardiac reprogramming of mouse fibroblasts with a single factor, Oct4." } ]

[ { "docid": "14797520", "text": "Nuclear transcription is not restricted to genes but occurs throughout the intergenic and noncoding space of eukaryotic genomes. The functional significance of this widespread noncoding transcription is mostly unknown. We show that Arabidopsis RNA polymerase IVb/Pol V, a multisubunit nuclear enzyme required for siRNA-mediated gene silencing of transposons and other repeats, transcribes intergenic and noncoding sequences, thereby facilitating heterochromatin formation and silencing of overlapping and adjacent genes. Pol IVb/Pol V transcription requires the chromatin-remodeling protein DRD1 but is independent of siRNA biogenesis. However, Pol IVb/Pol V transcription and siRNA production are both required to silence transposons, suggesting that Pol IVb/Pol V generates RNAs or chromatin structures that serve as scaffolds for siRNA-mediated heterochromatin-forming complexes. Pol IVb/Pol V function provides a solution to a paradox of epigenetic control: the need for transcription in order to transcriptionally silence the same region.", "title": "Noncoding Transcription by RNA Polymerase Pol IVb/Pol V Mediates Transcriptional Silencing of Overlapping and Adjacent Genes" } ]

[ { "docid": "1354567", "text": "In Arabidopsis thaliana, small interfering RNAs (siRNAs) direct cytosine methylation at endogenous DNA repeats in a pathway involving two forms of nuclear RNA polymerase IV (Pol IVa and Pol IVb), RNA-DEPENDENT RNA POLYMERASE 2 (RDR2), DICER-LIKE 3 (DCL3), ARGONAUTE4 (AGO4), the chromatin remodeler DRD1, and the de novo cytosine methyltransferase DRM2. We show that RDR2, DCL3, AGO4, and NRPD1b (the largest subunit of Pol IVb) colocalize with siRNAs within the nucleolus. By contrast, Pol IVa and DRD1 are external to the nucleolus and colocalize with endogenous repeat loci. Mutation-induced loss of pathway proteins causes downstream proteins to mislocalize, revealing their order of action. Pol IVa acts first, and its localization is RNA dependent, suggesting an RNA template. We hypothesize that maintenance of the heterochromatic state involves locus-specific Pol IVa transcription followed by siRNA production and assembly of AGO4- and NRPD1b-containing silencing complexes within nucleolar processing centers.", "title": "The Arabidopsis Chromatin-Modifying Nuclear siRNA Pathway Involves a Nucleolar RNA Processing Center" }, { "docid": "32275758", "text": "DNA polymerases mu (pol mu), lambda (pol lambda), and terminal deoxynucleotidyltransferase (TdT) are enzymes of the pol X family that share homology in sequence and functional domain organization. We showed previously that pol mu participates in light chain but surprisingly not heavy chain gene rearrangement. We show here that immunoglobulin heavy chain junctions from pol lambda-deficient animals have shorter length with normal N-additions, thus indicating that pol lambda is recruited during heavy chain rearrangement at a step that precedes the action of TdT. In contrast to previous in vitro studies, analysis of animals with combined inactivation of these enzymes revealed no overlapping or compensatory activities for V(D)J recombination between pol mu, pol lambda, and TdT. This complex usage of polymerases with distinct catalytic specificities may correspond to the specific function that the third hypervariable region assumes for each immunoglobulin chain, with pol lambda maintaining a large heavy chain junctional heterogeneity and pol mu ensuring a restricted light chain junctional variability.", "title": "Nonoverlapping functions of DNA polymerases mu, lambda, and terminal deoxynucleotidyltransferase during immunoglobulin V(D)J recombination in vivo." }, { "docid": "34559336", "text": "Three Pol X family members have been linked to nonhomologous end joining (NHEJ) in mammals. Template-independent TdT promotes diversity during NHEJ-dependent repair of V(D)J recombination intermediates, but the roles of the template-dependent polymerases mu and lambda in NHEJ remain unclear. We show here that pol mu and pol lambda are similarly recruited by NHEJ factors to fill gaps when ends have partially complementary overhangs, suggesting equivalent roles promoting accuracy in NHEJ. However, only pol mu promotes accuracy during immunoglobulin kappa recombination. This distinctive in vivo role correlates with the TdT-like ability of pol mu, but not pol lambda, to act when primer termini lack complementary bases in the template strand. However, unlike TdT, synthesis by pol mu in this context is primarily instructed by a template from another DNA molecule. This apparent gradient of template dependence is largely attributable to a small structural element that is present but different in all three polymerases.", "title": "A gradient of template dependence defines distinct biological roles for family X polymerases in nonhomologous end joining." }, { "docid": "13072112", "text": "A number of proteins and drugs have been implicated in the process of transcriptional elongation by RNA polymerase (Pol) II, but the factors that govern the elongation rate (nucleotide additions per min) and processivity (nucleotide additions per initiation event) in vivo are poorly understood. Here, we show that a mutation in the Rpb2 subunit of Pol II reduces both the elongation rate and processivity in vivo. In contrast, none of the putative elongation factors tested affect the elongation rate, although mutations in the THO complex and in Spt4 significantly reduce processivity. The drugs 6-azauracil and mycophenolic acid reduce both the elongation rate and processivity, and this processivity defect is aggravated by mutations in Spt4, TFIIS, and CTDK-1. Our results suggest that, in vivo, a reduced rate of Pol II elongation leads to premature dissociation along the chromatin template and that Pol II processivity can be uncoupled from elongation rate.", "title": "Distinction and relationship between elongation rate and processivity of RNA polymerase II in vivo." }, { "docid": "14380875", "text": "Glucocorticoids repress NFkappaB-mediated activation of proinflammatory genes such as interleukin-8 (IL-8) and ICAM-1. Our experiments suggest that the glucocorticoid receptor (GR) confers this effect by associating through protein-protein interactions with NFkappaB bound at each of these genes. That is, we show that the GR zinc binding region (ZBR), which includes the DNA binding and dimerization functions of the receptor, binds directly to the dimerization domain of the RelA subunit of NFkappaB in vitro and that the ZBR is sufficient to associate with RelA bound at NFkappaB response elements in vivo. Moreover, we demonstrate in vivo and in vitro that GR does not disrupt DNA binding by NFkappaB. In transient transfections, we found that the GR ligand binding domain is essential for repression of NFkappaB but not for association with it and that GR can repress an NFkappaB derivative bearing a heterologous activation domain. We used chromatin immunoprecipitation assays in untransfected A549 cells to infer the mechanism by which the tethered GR represses NFkappaB-activated transcription. As expected, we found that the inflammatory signal TNFalpha stimulated preinitiation complex (PIC) assembly at the IL-8 and ICAM-1 promoters and that the largest subunit of RNA polymerase II (pol II) in those complexes became phosphorylated at serines 2 and 5 in its carboxy-terminal domain (CTD) heptapeptide repeats (YSPTSPS); these modifications are required for transcription initiation. Remarkably, GR did not inhibit PIC assembly under repressing conditions, but rather interfered with phosphorylation of serine 2 of the pol II CTD.", "title": "The Glucocorticoid Receptor Inhibits" }, { "docid": "6670101", "text": "It is long been known that cancer and non-cancer cells can be distinguished on the basis of their nucleolar morphologies. As early as the 19th century, it was reported that cancer cells have larger and more irregularly shaped nucleoli. Since then, pathologists have used nucleolar morphology to predict the clinical outcome [1]. Nucleolar morphology is altered due to the up-regulation of ribosomal gene transcription. Within nucleoli, ribosomal genes (rDNA) are transcribed by RNA polymerase I (pol I). The pre-ribosomal RNA (pre-rRNA) transcripts are subsequently modified and processed into the mature 18S, 5.8S and 28S rRNAs. 5S rRNA is transcribed by RNA polymerase III in the nucleoplasm. Together with the ribosomal proteins, the 5S rRNA is imported into the nucleolus where 40S and 60S ribosomal subunits are assembled prior to export to the cytoplasm [1, 2]. Oncogenes such as c-Myc can both directly and indirectly upregulate rDNA transcription, while tumour suppressors like p53 and Rb suppress ribosome biogenesis. Mutations in these genes not only result in deregulated cell cycle control, but also upregulated ribosome biogenesis. In addition to ribosome biogenesis, the nucleolus is a key cellular stress sensor and plays a central role in p53 activation [1, 2]. The increased translational capacity of cancer cells enables them to maintain higher proliferation rates. As stated by Ruggero, “compared with normal cells, cancer cells may be addicted to increases in ribosome biogenesis and number” [1]. This provides new therapeutic opportunities. As it turns out many chemotherapeutic drugs used in cancer treatment already inhibit ribosome biogenesis. In one recent survey it was shown that 20 out of 36 drugs in clinical use inhibit ribosome biogenesis [3]. Most of these drugs were originally designed to target highly proliferating cells by damaging DNA, interfering with DNA synthesis or with mitosis. These targeting modalities of these drugs also lead to toxicity in normal highly proliferating tissues. An example is ActinomycinD (AMD), a DNA intercalator which has a preference for GC-rich DNA sequences. As rDNA has above average GC-richness and because of its open chromatin conformation, low concentrations of AMD preferentially inhibit RNA polymerase I transcription and upon prolonged exposure causes genome wide DNA damage. Alkylating drugs like cisplatin and oxaliplatin or topoisomerases poisons like camptothecin inhibit pol I transcription. The degree to which inhibition of ribosome biogenesis contributes to the efficacy of these drugs is difficult to establish [3]. This raises an important question. Can targeting ribosome biogenesis without DNA damage offer any therapeutic potential? Two recently described drugs CX-5461 and BMH-21 are now providing evidence that inhibition of ribosome biogenesis by targeting transcription of rDNA by pol I has promising therapeutic potential. CX-5461 was designed to specifically inhibit pol I transcription by disrupting pre-initiation complex formation at the rDNA promoter. CX-5461 has been shown to activate p53 via nucleolar stress. It induces autophagy as well as senescence in a multiple types of cancer cells in a p53-dependent manner. Especially in leukaemia and lymphoma cells, treatment with CX-5461 induces p53-dependent apoptosis, while normal cells tolerate it [4, 5]. Whether the drug also induces DNA damage was not fully addressed, but it was demonstrated that it could induce cell death in cells lacking ATM - a key mediator of DNA double strand break responses. However, more recently Laiho and colleagues have shown that at high concentrations, CX-5461 does induce a γH2AX response, raising concerns about DNA damage [6]. BMH-21 was identified in a screen performed by Laiho and colleagues aimed at identifying novel p53 activators. Like AMD, BMH-21 is a DNA intercalator with preference for GC rich sequences [7]. Continuing the parallel with AMD, BMH-21 is a potent and specific inhibitor rDNA transcription and induces nucleolar reorganisation often referred to as nucleolar capping. Interestingly, transcription inhibition was followed by the degradation of the main pol I subunit, RPA194, by the proteasome [6]. In contrast with AMD, initial indications were that BMH-21 did not appear to induce DNA damage as evidenced by the lack of a γH2AX response [7]. Inhibition of transcription by BMH-21 causes nucleolar stress, resulting in decreased proliferation and cell death. P53 is activated in BMH-21 treated cells but is not required for its anti-proliferative effects. Intriguingly, it appears that cancer cells with high demands for ribosome biogenesis are selectively targeted [6]. The current publication in Oncotarget now rules out any role for DNA damage signalling and repair pathways in the BMH-21 response. Moreover, BMH-21 derivatives that can induce DNA damage display lower efficiency in inducing nucleolar stress and inhibiting proliferation [8]. The central importance of this study is that it finally uncouples DNA damage and nucleolar stress and reveals an Achilles heel in cancer cells, their addiction to ribosome biogenesis.", "title": "Ribosome biogenesis: Achilles heel of cancer?" }, { "docid": "29788648", "text": "NuA4, the major H4 lysine acetyltransferase (KAT) complex in Saccharomyces cerevisiae, is recruited to promoters and stimulates transcription initiation. NuA4 subunits contain domains that bind methylated histones, suggesting that histone methylation should target NuA4 to coding sequences during transcription elongation. We show that NuA4 is cotranscriptionally recruited, dependent on its physical association with elongating polymerase II (Pol II) phosphorylated on the C-terminal domain by cyclin-dependent kinase 7/Kin28, but independently of subunits (Eaf1 and Tra1) required for NuA4 recruitment to promoters. Whereas histone methylation by Set1 and Set2 is dispensable for NuA4's interaction with Pol II and targeting to some coding regions, it stimulates NuA4-histone interaction and H4 acetylation in vivo. The NuA4 KAT, Esa1, mediates increased H4 acetylation and enhanced RSC occupancy and histone eviction in coding sequences and stimulates the rate of transcription elongation. Esa1 cooperates with the H3 KAT in SAGA, Gcn5, to enhance these functions. Our findings delineate a pathway for acetylation-mediated nucleosome remodeling and eviction in coding sequences that stimulates transcription elongation by Pol II in vivo.", "title": "NuA4 lysine acetyltransferase Esa1 is targeted to coding regions and stimulates transcription elongation with Gcn5." }, { "docid": "4465762", "text": "Transcription of eukaryotic protein-coding genes begins with assembly of the RNA polymerase (Pol) II initiation complex and promoter DNA opening. Here we report cryo-electron microscopy (cryo-EM) structures of yeast initiation complexes containing closed and open DNA at resolutions of 8.8 Å and 3.6 Å, respectively. DNA is positioned and retained over the Pol II cleft by a network of interactions between the TATA-box-binding protein TBP and transcription factors TFIIA, TFIIB, TFIIE, and TFIIF. DNA opening occurs around the tip of the Pol II clamp and the TFIIE ‘extended winged helix’ domain, and can occur in the absence of TFIIH. Loading of the DNA template strand into the active centre may be facilitated by movements of obstructing protein elements triggered by allosteric binding of the TFIIE ‘E-ribbon’ domain. The results suggest a unified model for transcription initiation with a key event, the trapping of open promoter DNA by extended protein–protein and protein–DNA contacts.", "title": "Transcription initiation complex structures elucidate DNA opening" }, { "docid": "7416873", "text": "Interphase nuclear repositioning of chromosomes has been implicated in the epigenetic regulation of RNA polymerase (pol) II transcription. However, little is known about the nuclear position–dependent regulation of RNA pol I–transcribed loci. Trypanosoma brucei is an excellent model system to address this question because its two main surface protein genes, procyclin and variant surface glycoprotein (VSG), are transcribed by pol I and undergo distinct transcriptional activation or downregulation events during developmental differentiation. Although the monoallelically expressed VSG locus is exclusively localized to an extranucleolar body in the bloodstream form, in this study, we report that nonmutually exclusive procyclin genes are located at the nucleolar periphery. Interestingly, ribosomal DNA loci and pol I transcription activity are restricted to similar perinucleolar positions. Upon developmental transcriptional downregulation, however, the active VSG promoter selectively undergoes a rapid and dramatic repositioning to the nuclear envelope. Subsequently, the VSG promoter region was subjected to chromatin condensation. We propose a model whereby the VSG expression site pol I promoter is selectively targeted by temporal nuclear repositioning during developmental silencing.", "title": "Nuclear repositioning of the VSG promoter during developmental silencing in Trypanosoma brucei" }, { "docid": "12149169", "text": "Synthesis of ribosomal RNA (rRNA) by RNA polymerase (Pol) I is the first step in ribosome biogenesis and a regulatory switch in eukaryotic cell growth. Here we report the 12 A cryo-electron microscopic structure for the complete 14-subunit yeast Pol I, a homology model for the core enzyme, and the crystal structure of the subcomplex A14/43. In the resulting hybrid structure of Pol I, A14/43, the clamp, and the dock domain contribute to a unique surface interacting with promoter-specific initiation factors. The Pol I-specific subunits A49 and A34.5 form a heterodimer near the enzyme funnel that acts as a built-in elongation factor and is related to the Pol II-associated factor TFIIF. In contrast to Pol II, Pol I has a strong intrinsic 3'-RNA cleavage activity, which requires the C-terminal domain of subunit A12.2 and, apparently, enables ribosomal RNA proofreading and 3'-end trimming.", "title": "Functional Architecture of RNA Polymerase I" }, { "docid": "25175223", "text": "RNA polymerase II is implicated in the RNA-templated RNA synthesis during replication of viroids and Hepatitis Delta Virus (HDV); however, neither the RNA template nor protein factor requirements for this process are well defined. We have developed an in vitro transcription system based on HeLa cell nuclear extract (NE), in which a segment of antigenomic RNA corresponding to the left-hand tip region of the HDV rod-like structure serves as a template for efficient and highly specific RNA synthesis. Accumulation of the unique RNA product is highly sensitive to alpha-amanitin in HeLa NE and only partially sensitive to this drug in NE from PMG cells that contain an allele of the alpha-amanitin-resistant subunit of pol II, strongly suggesting pol II involvement in this reaction. Detailed analysis of the RNA product revealed that it represents a chimeric molecule composed of a newly synthesized transcript covalently attached to the 5' half of the RNA template. Selection of the start site for transcription is remarkably specific and depends on the secondary structure of the RNA template, rather than on its primary sequence. Some features of this reaction resemble the RNA cleavage-extension process observed for pol II-arrested complexes in vitro. A possible involvement of the described reaction in HDV replication is discussed.", "title": "Specific HDV RNA-templated transcription by pol II in vitro." }, { "docid": "4162857", "text": "RNA processing is carried out in close proximity to the site of transcription, suggesting a regulatory link between transcription and pre-mRNA splicing. Using an in vitro transcription/splicing assay, we demonstrate that an association of RNA polymerase II (Pol II) transcription and pre-mRNA splicing is required for efficient gene expression. Pol II-synthesized RNAs containing functional splice sites are protected from nuclear degradation, presumably because the local concentration of the splicing machinery is sufficiently high to ensure its association over interactions with nucleases. Furthermore, the process of transcription influences alternative splicing of newly synthesized pre-mRNAs. Because other RNA polymerases do not provide similar protection from nucleases, and their RNA products display altered splicing patterns, the link between transcription and RNA processing is RNA Pol II-specific. We propose that the connection between transcription by Pol II and pre-mRNA splicing guarantees an extended half-life and proper processing of nascent pre-mRNAs.", "title": "Linking Splicing to Pol II Transcription Stabilizes Pre-mRNAs and Influences Splicing Patterns" }, { "docid": "4393153", "text": "RNA polymerase (Pol) II catalyses DNA-dependent RNA synthesis during gene transcription. There is, however, evidence that Pol II also possesses RNA-dependent RNA polymerase (RdRP) activity. Pol II can use a homopolymeric RNA template, can extend RNA by several nucleotides in the absence of DNA, and has been implicated in the replication of the RNA genomes of hepatitis delta virus (HDV) and plant viroids. Here we show the intrinsic RdRP activity of Pol II with only pure polymerase, an RNA template–product scaffold and nucleoside triphosphates (NTPs). Crystallography reveals the template–product duplex in the site occupied by the DNA–RNA hybrid during transcription. RdRP activity resides at the active site used during transcription, but it is slower and less processive than DNA-dependent activity. RdRP activity is also obtained with part of the HDV antigenome. The complex of transcription factor IIS (TFIIS) with Pol II can cleave one HDV strand, create a reactive stem-loop in the hybrid site, and extend the new RNA 3′ end. Short RNA stem-loops with a 5′ extension suffice for activity, but their growth to a critical length apparently impairs processivity. The RdRP activity of Pol II provides a missing link in molecular evolution, because it suggests that Pol II evolved from an ancient replicase that duplicated RNA genomes.", "title": "Molecular basis of RNA-dependent RNA polymerase II activity" }, { "docid": "25186412", "text": "The PANTHER (protein annotation through evolutionary relationship) classification system (http://www.pantherdb.org/) is a comprehensive system that combines gene function, ontology, pathways and statistical analysis tools that enable biologists to analyze large-scale, genome-wide data from sequencing, proteomics or gene expression experiments. The system is built with 82 complete genomes organized into gene families and subfamilies, and their evolutionary relationships are captured in phylogenetic trees, multiple sequence alignments and statistical models (hidden Markov models or HMMs). Genes are classified according to their function in several different ways: families and subfamilies are annotated with ontology terms (Gene Ontology (GO) and PANTHER protein class), and sequences are assigned to PANTHER pathways. The PANTHER website includes a suite of tools that enable users to browse and query gene functions, and to analyze large-scale experimental data with a number of statistical tests. It is widely used by bench scientists, bioinformaticians, computer scientists and systems biologists. In the 2013 release of PANTHER (v.8.0), in addition to an update of the data content, we redesigned the website interface to improve both user experience and the system's analytical capability. This protocol provides a detailed description of how to analyze genome-wide experimental data with the PANTHER classification system.", "title": "Large-scale gene function analysis with the PANTHER classification system" }, { "docid": "3847200", "text": "Direct induction of induced hepatocytes (iHeps) from fibroblasts holds potential as a strategy for regenerative medicine but until now has only been shown in culture settings. Here, we describe in vivo iHep formation using transcription factor induction and genetic fate tracing in mouse models of chronic liver disease. We show that ectopic expression of the transcription factors FOXA3, GATA4, HNF1A, and HNF4A from a polycistronic lentiviral vector converts mouse myofibroblasts into cells with a hepatocyte phenotype. In vivo expression of the same set of transcription factors from a p75 neurotrophin receptor peptide (p75NTRp)-tagged adenovirus enabled the generation of hepatocyte-like cells from myofibroblasts in fibrotic mouse livers and reduced liver fibrosis. We have therefore been able to convert pro-fibrogenic myofibroblasts in the liver into hepatocyte-like cells with positive functional benefits. This direct in vivo reprogramming approach may open new avenues for the treatment of chronic liver disease.", "title": "Direct Reprogramming of Hepatic Myofibroblasts into Hepatocytes In Vivo Attenuates Liver Fibrosis." }, { "docid": "27635177", "text": "Mammalian DNA polymerase mu (pol mu) is related to terminal deoxynucleotidyl transferase, but its biological role is not yet clear. We show here that after exposure of cells to ionizing radiation (IR), levels of pol mu protein increase. pol mu also forms discrete nuclear foci after IR, and these foci are largely coincident with IR-induced foci of gammaH2AX, a previously characterized marker of sites of DNA double-strand breaks. pol mu is thus part of the cellular response to DNA double-strand breaks. pol mu also associates in cell extracts with the nonhomologous end-joining repair factor Ku and requires both Ku and another end-joining factor, XRCC4-ligase IV, to form a stable complex on DNA in vitro. pol mu in turn facilitates both stable recruitment of XRCC4-ligase IV to Ku-bound DNA and ligase IV-dependent end joining. In contrast, the related mammalian DNA polymerase beta does not form a complex with Ku and XRCC4-ligase IV and is less effective than pol mu in facilitating joining mediated by these factors. Our data thus support an important role for pol mu in the end-joining pathway for repair of double-strand breaks.", "title": "Association of DNA polymerase mu (pol mu) with Ku and ligase IV: role for pol mu in end-joining double-strand break repair." }, { "docid": "41852733", "text": "Ehlers-Danlos syndrome (EDS) type I (the classical variety) is a dominantly inherited, genetically heterogeneous connective-tissue disorder. Mutations in the COL5A1 and COL5A2 genes, which encode type V collagen, have been identified in several individuals. Most mutations affect either the triple-helical domain of the protein or the expression of one COL5A1 allele. We identified a novel splice-acceptor mutation (IVS4-2A-->G) in the N-propeptide-encoding region of COL5A1, in one patient with EDS type I. The outcome of this mutation was complex: In the major product, both exons 5 and 6 were skipped; other products included a small amount in which only exon 5 was skipped and an even smaller amount in which cryptic acceptor sites within exon 5 were used. All products were in frame. Pro-alpha1(V) chains with abnormal N-propeptides were secreted and were incorporated into extracellular matrix, and the mutation resulted in dramatic alterations in collagen fibril structure. The two-exon skip occurred in transcripts in which intron 5 was removed rapidly relative to introns 4 and 6, leaving a large (270 nt) composite exon that can be skipped in its entirety. The transcripts in which only exon 5 was skipped were derived from those in which intron 6 was removed prior to intron 5. The use of cryptic acceptor sites in exon 5 occurred in transcripts in which intron 4 was removed subsequent to introns 5 and 6. These findings suggest that the order of intron removal plays an important role in the outcome of splice-site mutations and provide a model that explains why multiple products derive from a mutation at a single splice site.", "title": "Order of intron removal influences multiple splice outcomes, including a two-exon skip, in a COL5A1 acceptor-site mutation that results in abnormal pro-alpha1(V) N-propeptides and Ehlers-Danlos syndrome type I." }, { "docid": "1782201", "text": "Integrins regulate adhesion-dependent growth, survival and invasion of tumor cells. In particular, expression of integrin alpha(v)beta(3) is associated with progression of a variety of human tumors. Here we reveal a previously undescribed adhesion-independent role for integrin alpha(v)beta(3) in pancreatic cancer and other carcinomas. Specifically, alpha(v)beta(3) expressed in carcinoma cells enhanced anchorage-independent tumor growth in vitro and increased lymph node metastases in vivo. These effects required recruitment of c-Src to the beta(3) integrin cytoplasmic tail, leading to c-Src activation, Crk-associated substrate (CAS) phosphorylation and tumor cell survival that, unexpectedly, was independent of cell adhesion or focal adhesion kinase (FAK) activation. Pharmacological blockade of c-Src kinase activity or decreased expression of endogenous alpha(v)beta(3) integrin or c-Src not only inhibited anchorage-independent growth but also suppressed metastasis in vivo, yet these manipulations did not affect tumor cell migration or invasion. These data define an unexpected role for an integrin as a mediator of anchorage independence, suggesting that an alpha(v)beta(3)-c-Src signaling module may account for the aggressive behavior of integrin alpha(v)beta(3)-expressing tumors in humans.", "title": "Integrin αvβ3/c-src “Oncogenic Unit” Promotes Anchorage-independence and Tumor Progression" }, { "docid": "26899920", "text": "It was recently shown that mouse fibroblasts could be reprogrammed into cells of a cardiac fate by forced expression of multiple transcription factors and microRNAs. For ultimate application of such a reprogramming strategy for cell-based therapy or in vivo cardiac regeneration, reducing or eliminating the genetic manipulations by small molecules would be highly desirable. Here, we report the identification of a defined small-molecule cocktail that enables the highly efficient conversion of mouse fibroblasts into cardiac cells with only one transcription factor, Oct4, without any evidence of entrance into the pluripotent state. Small-molecule-induced cardiomyocytes spontaneously contract and exhibit a ventricular phenotype. Furthermore, these induced cardiomyocytes pass through a cardiac progenitor stage. This study lays the foundation for future pharmacological reprogramming approaches and provides a small-molecule condition for investigation of the mechanisms underlying the cardiac reprogramming process.", "title": "Small molecules enable cardiac reprogramming of mouse fibroblasts with a single factor, Oct4." } ]

[ { "docid": "7821634", "text": "Neoadjuvant chemotherapy (NAC) induces a pathological complete response (pCR) in ∼30% of patients with breast cancer. However, many patients have residual cancer after chemotherapy, which correlates with a higher risk of metastatic recurrence and poorer outcome than those who achieve a pCR. We hypothesized that molecular profiling of tumors after NAC would identify genes associated with drug resistance. Digital transcript counting was used to profile surgically resected breast cancers after NAC. Low concentrations of dual specificity protein phosphatase 4 (DUSP4), an ERK phosphatase, correlated with high post-NAC tumor cell proliferation and with basal-like breast cancer (BLBC) status. BLBC had higher DUSP4 promoter methylation and gene expression patterns of Ras-ERK pathway activation relative to other breast cancer subtypes. DUSP4 overexpression increased chemotherapy-induced apoptosis, whereas DUSP4 depletion dampened the response to chemotherapy. Reduced DUSP4 expression in primary tumors after NAC was associated with treatment-refractory high Ki-67 scores and shorter recurrence-free survival. Finally, inhibition of mitogen-activated protein kinase kinase (MEK) synergized with docetaxel treatment in BLBC xenografts. Thus, DUSP4 downregulation activates the Ras-ERK pathway in BLBC, resulting in an attenuated response to anti-cancer chemotherapy.", "title": "Profiling of residual breast cancers after neoadjuvant chemotherapy identifies DUSP4 deficiency as a mechanism of drug resistance" } ]

[ { "docid": "24190159", "text": "Mutations of the KRAS oncogene are predictive for resistance to treatment with antibodies against the epithelial growth factor receptor in patients with colorectal cancer. Overcoming this therapeutic dilemma could potentially be achieved by the introduction of drugs that inhibit signaling pathways that are activated by KRAS mutations. To identify comprehensively such signaling pathways, we profiled pretreatment biopsies and normal mucosa from 65 patients with locally advanced rectal cancer-30 of which carried mutated KRAS-using global gene expression microarrays. By comparing all tumor tissues exclusively to matched normal mucosa, we could improve assay sensitivity, and identified a total of 22,297 features that were differentially expressed (adjusted P-value <0.05) between normal mucosa and cancer, including several novel potential rectal cancer genes. We then used this comprehensive description of the rectal cancer transcriptome as the baseline for identifying KRAS-dependent alterations. The presence of activating KRAS mutations is significantly correlated to an upregulation of 13 genes (adjusted P-value <0.05), among them DUSP4, a MAP-kinase phosphatase, and SMYD3, a histone methyltransferase. Inhibition of the expression of both genes has previously been shown using the MEK1-inhibitor PD98059 and the antibacterial compound Novobiocin, respectively. These findings suggest a potential approach to overcome resistance to treatment with antibodies against the epithelial growth factor receptor in patients with KRAS-mutant rectal carcinomas.", "title": "Mutated KRAS results in overexpression of DUSP4, a MAP-kinase phosphatase, and SMYD3, a histone methyltransferase, in rectal carcinomas." }, { "docid": "15248287", "text": "Neutrophil apoptosis is a highly regulated process essential for inflammation resolution, the molecular mechanisms of which are only partially elucidated. In this study, we describe a survival pathway controlled by proliferating cell nuclear antigen (PCNA), a nuclear factor involved in DNA replication and repairing of proliferating cells. We show that mature neutrophils, despite their inability to proliferate, express high levels of PCNA exclusively in their cytosol and constitutively associated with procaspases, presumably to prevent their activation. Notably, cytosolic PCNA abundance decreased during apoptosis, and increased during in vitro and in vivo exposure to the survival factor granulocyte colony-stimulating factor (G-CSF). Peptides derived from the cyclin-dependent kinase inhibitor p21, which compete with procaspases to bind PCNA, triggered neutrophil apoptosis thus demonstrating that specific modification of PCNA protein interactions affects neutrophil survival. Furthermore, PCNA overexpression rendered neutrophil-differentiated PLB985 myeloid cells significantly more resistant to TNF-related apoptosis-inducing ligand- or gliotoxin-induced apoptosis. Conversely, a decrease in PCNA expression after PCNA small interfering RNA transfection sensitized these cells to apoptosis. Finally, a mutation in the PCNA interdomain-connecting loop, the binding site for many partners, significantly decreased the PCNA-mediated antiapoptotic effect. These results identify PCNA as a regulator of neutrophil lifespan, thereby highlighting a novel target to potentially modulate pathological inflammation.", "title": "Proliferating cell nuclear antigen acts as a cytoplasmic platform controlling human neutrophil survival" }, { "docid": "23403754", "text": "In this review I summarize interrelations between bioenergetic processes and such programmed death phenomena as cell suicide (apoptosis and necrosis) and mitochondrial suicide (mitoptosis). The following conclusions are made. (I) ATP and rather often mitochondrial hyperpolarization (i.e. an increase in membrane potential, ΔΨ) are required for certain steps of apoptosis and necrosis. (II) Apoptosis, even if it is accompanied by ΔΨ and [ATP] increases at its early stage, finally results in a ΔΨ collapse and ATP decrease. (III) Moderate (about three-fold) lowering of [ATP] for short and long periods of time induces apoptosis and necrosis, respectively. In some types of apoptosis and necrosis, the cell death is mediated by a ΔΨ-dependent overproduction of ROS by the initial (Complex I) and the middle (Complex III) spans of the respiratory chain. ROS initiate mitoptosis which is postulated to rid the intracellular population of mitochondria from those that are ROS overproducing. Massive mitoptosis can result in cell death due to release to cytosol of the cell death proteins normally hidden in the mitochondrial intermembrane space.", "title": "Bioenergetic aspects of apoptosis, necrosis and mitoptosis" }, { "docid": "20738970", "text": "Epithelial and endothelial tyrosine kinase (Etk), also known as Bmx (bone marrow X kinase) plays an important role in apoptosis of epithelial cells. The goal of this study was to investigate whether Etk is involved in apoptosis of small cell lung cancer (SCLC) cells and correlated with the expression levels of apoptosis-associated proteins such as Bcl-2, Bcl-X(L) and p53. One hundred and seventy-one cases of lung cancer specimens including seventy-one SCLCs and one hundred NSCLCs were immunostained for Etk, Bcl-2, Bcl-X(L) and p53. Parental SCLC H446 cell line, and its subline (H446-Etk) that overexpresses Etk, were used to study the role of Etk in apoptosis induced by doxorubicin. It was found that high expression of Etk occurs in 74.6% of SCLC cases, but only in 40% of NSCLC cases, and there is marked difference in the expression levels of Bcl-2, Bcl-X(L) and p53 between Etk-positive and Etk-negative SCLC cases. Furthermore, the levels of Bcl-2 and Bcl-X(L) significantly increased in H446-Etk cells than that in H446 cells after doxorubicin treatment, and were positively associated with Etk expression. However, p53 did not correspond with Etk expression although its expression decreased greatly with apoptosis both in H446-Etk and H446 cells. After doxorubicin treatment, the cell viability was significantly higher in H446-Etk cells than in parental H446 cells. Downregulation of Etk by Etk siRNA sensitized H446 cells to doxorubicin. Our results indicate that upregulation of tyrosine kinase Etk may be a new mechanism involved in protection of SCLC cells from apoptosis. Bcl-2 and Bcl-X(L) but not p53 may contribute to doxorubicin-induced apoptosis through Etk pathway.", "title": "Non-receptor tyrosine kinase Etk is involved in the apoptosis of small cell lung cancer cells." }, { "docid": "40901687", "text": "The DNA damage response (DDR) is a complex regulatory network that is critical for maintaining genome integrity. Posttranslational modifications are widely used to ensure strict spatiotemporal control of signal flow, but how the DDR responds to environmental cues, such as changes in ambient oxygen tension, remains poorly understood. We found that an essential component of the ATR/CHK1 signaling pathway, the human homolog of the Caenorhabditis elegans biological clock protein CLK-2 (HCLK2), associated with and was hydroxylated by prolyl hydroxylase domain protein 3 (PHD3). HCLK2 hydroxylation was necessary for its interaction with ATR and the subsequent activation of ATR/CHK1/p53. Inhibiting PHD3, either with the pan-hydroxylase inhibitor dimethyloxaloylglycine (DMOG) or through hypoxia, prevented activation of the ATR/CHK1/p53 pathway and decreased apoptosis induced by DNA damage. Consistent with these observations, we found that mice lacking PHD3 were resistant to the effects of ionizing radiation and had decreased thymic apoptosis, a biomarker of genomic integrity. Our identification of HCLK2 as a substrate of PHD3 reveals the mechanism through which hypoxia inhibits the DDR, suggesting hydroxylation of HCLK2 is a potential therapeutic target for regulating the ATR/CHK1/p53 pathway.", "title": "PHD3-dependent hydroxylation of HCLK2 promotes the DNA damage response." }, { "docid": "9588931", "text": "Vascular calcification is a strong independent predictor of increased cardiovascular morbidity and mortality and has a high prevalence among patients with chronic kidney disease. The present study investigated the effects of quercetin on vascular calcification caused by oxidative stress and abnormal mitochondrial dynamics both in vitro and in vivo. Calcifying vascular smooth muscle cells (VSMCs) treated with inorganic phosphate (Pi) exhibited mitochondrial dysfunction, as demonstrated by decreased mitochondrial potential and ATP production. Disruption of mitochondrial structural integrity was also observed in a rat model of adenine-induced aortic calcification. Increased production of reactive oxygen species, enhanced expression and phosphorylation of Drp1, and excessive mitochondrial fragmentation were also observed in Pi-treated VSMCs. These effects were accompanied by mitochondria-dependent apoptotic events, including release of cytochrome c from the mitochondria into the cytosol and subsequent activation of caspase-3. Quercetin was shown to block Pi-induced apoptosis and calcification of VSMCs by inhibiting oxidative stress and decreasing mitochondrial fission by inhibiting the expression and phosphorylation of Drp1. Quercetin also significantly ameliorated adenine-induced aortic calcification in rats. In summary, our findings suggest that quercetin attenuates calcification by reducing apoptosis of VSMCs by blocking oxidative stress and inhibiting mitochondrial fission.", "title": "Quercetin attenuates vascular calcification by inhibiting oxidative stress and mitochondrial fission." }, { "docid": "10576136", "text": "BACKGROUND ST2 is an interleukin (IL)-1 receptor family member with membrane-bound (ST2L) and soluble (sST2) isoforms, and sST2 is a biomarker for poor outcome in patients with myocardial infarction (MI). IL-33, the recently discovered ligand for ST2, activates nuclear factor kappaB and thus may regulate apoptotic cell death. We tested the hypothesis that IL-33 is cardioprotective after MI through ST2 signaling. \n METHODS AND RESULTS IL-33 protected cultured cardiomyocytes from hypoxia-induced apoptosis, and this cardioprotection was partially inhibited by sST2. IL-33 induced expression of the antiapoptotic factors XIAP, cIAP1, and survivin. To define the cardioprotective role of IL-33 in vivo, we performed a blinded and randomized study of ischemia/reperfusion in rats. IL-33 reduced cardiomyocyte apoptosis, suppressed caspase-3 activity, and increased expression of IAP family member proteins. IL-33 decreased both infarct and fibrosis volumes at 15 days; furthermore, both echocardiographic and hemodynamic studies revealed that IL-33 improved ventricular function. To determine whether cardioprotection by IL-33 is mediated through ST2 signaling, a randomized and blinded study of ST2(-/-) versus wild-type littermate mice was performed in 98 mice subjected to MI. At 4 weeks after MI, IL-33 reduced ventricular dilation and improved contractile function in wild-type mice but not in ST2(-/-) mice. Finally, IL-33 improved survival after MI in wild-type but not in ST2(-/-) mice. \n CONCLUSIONS IL-33 prevents cardiomyocyte apoptosis and improves cardiac function and survival after MI through ST2 signaling.", "title": "Interleukin-33 prevents apoptosis and improves survival after experimental myocardial infarction through ST2 signaling." }, { "docid": "27460509", "text": "Cardiac myocyte apoptosis has been demonstrated in end-stage failing human hearts. The therapeutic utility of blocking apoptosis in congestive heart failure (CHF) has not been elucidated. This study investigated the role of caspase activation in cardiac contractility and sarcomere organization in the development of CHF. In a rabbit model of heart failure obtained by rapid ventricular pacing, we demonstrate, using in vivo transcoronary adenovirus-mediated gene delivery of the potent caspase inhibitor p35, that caspase activation is associated with a reduction in contractile force of failing myocytes by destroying sarcomeric structure. In this animal model gene transfer of p35 prevented the rise in caspase 3 activity and DNA-histone formation. Genetically manipulated hearts expressing p35 had a significant improvement in left ventricular pressure rise (+dp/dt), decreased end-diastolic chamber pressure (LVEDP), and the development of heart failure was delayed. To better understand this benefit, we examined the effects of caspase 3 on cardiomyocyte dysfunction in vitro. Microinjection of activated caspase 3 into the cytoplasm of intact myocytes induced sarcomeric disorganization and reduced contractility of the cells. These results demonstrate a direct impact of caspases on cardiac function and may lead to novel therapeutic strategies via antiapoptotic regimens.", "title": "Blocking caspase-activated apoptosis improves contractility in failing myocardium." }, { "docid": "39424916", "text": "Wedelolactone is a major coumarin of Eclipta prostrata, which is used for preventing liver damage. However the effects of wedelolactone on hepatic fibrosis remained unexplored. The purpose of this study was to demonstrate the anti-fibrotic effects of wedelolactone on activated human hepatic stellate cell (HSC) line LX-2 and the possible underlying mechanisms by means of MTT assay, Hoechst staining, as well as real-time quantitative PCR and western blot. The results showed that wedelolactone reduced the cellular viability of LX-2 in a time and dose-dependent manner. After treatment of wedelolactone, the expressions of collagen I and α-smooth muscle actin, two biomarkers of LX-2 activation, were remarkably decreased. The apoptosis of LX-2 cells was induced by wedelolactone accompanied with the decreasing expression of anti-apoptotic Bcl-2 and increasing expression of pro-apoptotic Bax. In addition, phosphorylated status of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was up-regulated, but not in p38. Moreover, wedelolactone significantly repressed the level of phosphorylated inhibitor of nuclear factor κB (IκB) and p65 in nucleus in spite of tumor necrosis factor-α stimulation. In conclusion, wedelolactone could significantly inhibit the activation of LX-2 cells, the underlying mechanisms of which included inducing Bcl-2 family involved apoptosis, up-regulating phosphorylated status of ERK and JNK expressions, and inhibiting nuclear factor-κB (NF-κB) mediated activity. Wedelolactone might present as a useful tool for the prevention and treatment of hepatic fibrosis.", "title": "Wedelolactone exhibits anti-fibrotic effects on human hepatic stellate cell line LX-2." }, { "docid": "17231273", "text": "Energy deficiency and dysfunction of the Na+, K+-ATPase are common consequences of many pathological insults. The nature and mechanism of cell injury induced by impaired Na+, K+-ATPase, however, are not well defined. We used cultured cortical neurons to examine the hypothesis that blocking the Na+, K+-ATPase induces apoptosis by depleting cellular K+ and, concurrently, induces necrotic injury in the same cells by increasing intracellular Ca2+ and Na+. The Na+, K+-ATPase inhibitor ouabain induced concentration-dependent neuronal death. Ouabain triggered transient neuronal cell swelling followed by cell shrinkage, accompanied by intracellular Ca2+ and Na+ increase, K+ decrease, cytochrome c release, caspase-3 activation, and DNA laddering. Electron microscopy revealed the coexistence of ultrastructural features of both apoptosis and necrosis in individual cells. The caspase inhibitor Z-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD-FMK) blocked >50% of ouabain-induced neuronal death. Potassium channel blockers or high K+ medium, but not Ca2+ channel blockade, prevented cytochrome c release, caspase activation, and DNA damage. Blocking of K+, Ca2+, or Na+ channels or high K+ medium each attenuated the ouabain-induced cell death; combined inhibition of K+ channels and Ca2+ or Na+ channels resulted in additional protection. Moreover, coapplication of Z-VAD-FMK and nifedipine produced virtually complete neuroprotection. These results suggest that the neuronal death associated with Na+, K+-pump failure consists of concurrent apoptotic and necrotic components, mediated by intracellular depletion of K+ and accumulation of Ca2+ and Na+, respectively. The ouabain-induced hybrid death may represent a distinct form of cell death related to the brain injury of inadequate energy supply and disrupted ion homeostasis.", "title": "Ionic mechanism of ouabain-induced concurrent apoptosis and necrosis in individual cultured cortical neurons" }, { "docid": "16058322", "text": "beta-Cell destruction in type 1 diabetes (T1D) is at least in part consequence of a 'dialog' between beta-cells and immune system. This dialog may be affected by the individual's genetic background. We presently evaluated whether modulation of MDA5 and PTPN2, two candidate genes for T1D, affects beta-cell responses to double-stranded RNA (dsRNA), a by-product of viral replication. These genes were selected following comparison between known candidate genes for T1D and genes expressed in pancreatic beta-cells, as identified in previous array analysis. INS-1E cells and primary fluorescence-activated cell sorting-purified rat beta-cells were transfected with small interference RNAs (siRNAs) targeting MDA5 or PTPN2 and subsequently exposed to intracellular synthetic dsRNA (polyinosinic-polycitidilic acid-PIC). Real-time RT-PCR, western blot and viability assays were performed to characterize gene/protein expression and viability. PIC increased MDA5 and PTPN2 mRNA expression, which was inhibited by the specific siRNAs. PIC triggered apoptosis in INS-1E and primary beta-cells and this was augmented by PTPN2 knockdown (KD), although inhibition of MDA5 did not modify PIC-induced apoptosis. In contrast, MDA5 silencing decreased PIC-induced cytokine and chemokine expression, although inhibition of PTPN2 induced minor or no changes in these inflammatory mediators. These findings indicate that changes in MDA5 and PTPN2 expression modify beta-cell responses to dsRNA. MDA5 regulates inflammatory signals, whereas PTPN2 may function as a defence mechanism against pro-apoptotic signals generated by dsRNA. These two candidate genes for T1D may thus modulate beta-cell apoptosis and/or local release of inflammatory mediators in the course of a viral infection by acting, at least in part, at the pancreatic beta-cell level.", "title": "MDA5 and PTPN2, two candidate genes for type 1 diabetes, modify pancreatic β-cell responses to the viral by-product double-stranded RNA" }, { "docid": "9197092", "text": "Dietary polyphenols have been associated with reduced risk of chronic diseases, but the precise molecular mechanisms of protection remain unclear. This work was aimed at studying the effect of (-)-epicatechin (EC) and chlorogenic acid (CGA) on the regulation of apoptotic and survival/proliferation pathways in a human hepatoma cell line (HepG2). EC or CGA treatment for 18 h had a slight effect on cell viability and decreased reactive oxygen species formation, and EC alone promoted cell proliferation, whereas CGA increased glutathione levels. Phenols neither induced the caspase cascade for apoptosis nor affected expression levels of Bcl-xL or Bax. A sustained activation of the major survival signals AKT/PI-3-kinase and ERK was shown in EC-treated cells, rather than in CGA-exposed cells. These data suggest that EC and CGA have no effect on apoptosis and enhance the intrinsic cellular tolerance against oxidative insults either by activating survival/proliferation pathways or by increasing antioxidant potential in HepG2.", "title": "Molecular mechanisms of (-)-epicatechin and chlorogenic acid on the regulation of the apoptotic and survival/proliferation pathways in a human hepatoma cell line." }, { "docid": "33370", "text": "Glioblastomas are deadly cancers that display a functional cellular hierarchy maintained by self-renewing glioblastoma stem cells (GSCs). GSCs are regulated by molecular pathways distinct from the bulk tumor that may be useful therapeutic targets. We determined that A20 (TNFAIP3), a regulator of cell survival and the NF-kappaB pathway, is overexpressed in GSCs relative to non-stem glioblastoma cells at both the mRNA and protein levels. To determine the functional significance of A20 in GSCs, we targeted A20 expression with lentiviral-mediated delivery of short hairpin RNA (shRNA). Inhibiting A20 expression decreased GSC growth and survival through mechanisms associated with decreased cell-cycle progression and decreased phosphorylation of p65/RelA. Elevated levels of A20 in GSCs contributed to apoptotic resistance: GSCs were less susceptible to TNFalpha-induced cell death than matched non-stem glioma cells, but A20 knockdown sensitized GSCs to TNFalpha-mediated apoptosis. The decreased survival of GSCs upon A20 knockdown contributed to the reduced ability of these cells to self-renew in primary and secondary neurosphere formation assays. The tumorigenic potential of GSCs was decreased with A20 targeting, resulting in increased survival of mice bearing human glioma xenografts. In silico analysis of a glioma patient genomic database indicates that A20 overexpression and amplification is inversely correlated with survival. Together these data indicate that A20 contributes to glioma maintenance through effects on the glioma stem cell subpopulation. Although inactivating mutations in A20 in lymphoma suggest A20 can act as a tumor suppressor, similar point mutations have not been identified through glioma genomic sequencing: in fact, our data suggest A20 may function as a tumor enhancer in glioma through promotion of GSC survival. A20 anticancer therapies should therefore be viewed with caution as effects will likely differ depending on the tumor type.", "title": "Targeting A20 Decreases Glioma Stem Cell Survival and Tumor Growth" }, { "docid": "16346504", "text": "BACKGROUND Growth arrest-specific 5 (GAS5) was reported to be implicated and aberrantly express in multiple cancers. However, the expression and mechanism of action of GAS5 were largely poor understood in endometrial carcinoma. \n RESULTS According to the result of real-time reverse-transcriptase polymerase chain reaction (RT-PCR) and flow cytometry analysis, we identified that GAS5 was down-regulated in endometrial cancer cells and stimulated the apoptosis of endometrial cancer cells. To investigate the expression of GAS5, PTEN and miR-103, RT-PCR was performed. And we found that the expression of PTEN was up-regulated when endometrial cancer cells overexpressed GAS5. The prediction of bioinformatics online revealed that GAS5 could bind to miR-103, which was further found to be regulated by GAS5. Finally, we found that miR-103 mimic could decrease the mRNA and protein levels of PTEN through luciferase reporter assay and western blotting, and GAS5 plasmid may reverse this regulation effect in endometrial cancer cells. \n CONCLUSION In summary, we demonstrate that GAS5 acts as an tumor suppressor lncRNA in endometrial cancer. Through inhibiting the expression of miR-103, GAS5 significantly enhanced the expression of PTEN to promote cancer cell apoptosis, and, thus, could be an important mediator in the pathogenesis of endometrial cancer.", "title": "LncRNA-GAS5 induces PTEN expression through inhibiting miR-103 in endometrial cancer cells" }, { "docid": "10852047", "text": "We recently developed a class of novel antitumor agents that elicit a potent growth-inhibitory response in many tumor cells cultured in vitro. WK175, a member of this class, was chosen as a model compound that showed strong in vitro efficacy. WK175 interferes with the intracellular steady-state level of NAD(+), resulting in a decreased cellular NAD(+) concentration. We found that WK175 induces apoptotic cell death without any DNA-damaging effect. The apoptotic death signaling pathway initiated by WK175 was examined in detail: mitochondrial membrane potential, cytochrome c release, caspase 3 activation, caspase 3 and poly(ADP-ribose) polymerase cleavage, and the appearance of a sub-G(1) cell cycle population were determined in time course studies in THP-1 (a human monocytic leukemia cell line) cells. We found activation of this cascade after 24 h of treatment with 10 nM WK175. Induction of apoptosis was prevented by bongkrekic acid, Z-Asp-Glu-Val-Asp-fluoromethylketone, and Z-Leu-Glu-His-Asp-fluoromethylketone, inhibitors of the mitochondrial permeability transition and of caspase 3 and 9, respectively, but not by Ac-Tyr-Val-Ala-Asp-CHO, a specific caspase 1 inhibitor, suggesting the involvement of the permeability transition pore, caspase 3, and caspase 9 in the WK175-induced apoptotic cascade. These results imply that decreased NAD(+) concentration initiates the apoptotic cascade, resulting in the antitumor effect of WK175.", "title": "WK175, a novel antitumor agent, decreases the intracellular nicotinamide adenine dinucleotide concentration and induces the apoptotic cascade in human leukemia cells." }, { "docid": "20287253", "text": "Congenital obstructive nephropathy is a consequence abnormal urinary tract development resulting in renal growth failure and injury manifested by progressive tubular atrophy and interstitial fibrosis. We have studied the renal cellular and physiological response to unilateral ureteral obstruction (UUO) in the neonatal rodent (guinea pig, rat, and mouse). Whereas in the adult, UUO stimulates renal cellular proliferation, UUO in the neonate reduces nephrogenesis, glomerular maturation, and tubular cellular proliferation. This is accompanied by a proportionately greater compensatory growth of the intact opposite kidney in the neonate. Impaired renal growth and tubular atrophy are likely owing at least in part to stimulation of renal tubular apoptosis. This, in turn, may result from a combination of factors, including loss of epithelial cell polarity, a reduction in the oncoprotein bcl-2 and epidermal growth factor (EGF), and increased expression of the fibrogenic cytokine, transforming growth factor-beta1 (TGF-beta1). Infusion of EGF stimulates cellular proliferation, suppresses apoptosis, and reduces tubular atrophy and interstitial fibrosis. TGF-beta1 is regulated by the renin-angiotensin system, which is markedly activated by UUO in the neonate. The functional consequences of obstructive nephropathy in early development are hyperfiltration by remaining nephrons, followed by progressive decrease in glomerular filtration rate that may only develop in later life. Improved management of congenital urinary tract obstruction will depend on a better understanding of the cellular mechanisms, which may lead to specific treatment using gene therapy or modulators of renal growth and development.", "title": "Pathophysiology of obstructive nephropathy in the newborn." }, { "docid": "24186125", "text": "Quercetin may have the opposite effect, namely anti- as well as pro-oxidant. The aim of this study was to assess the results of quercetin anti- and/or pro-oxidant activity in the bone marrow and spleen cells of rats. The experimental rats were treated daily, with quercetin in a dose of 8 or 80mg/kg b.w. by gavage for 40 days. The intracellular redox state in cells were assessed by measuring the ferric ion reducing antioxidant power (FRAP) level and malonodialdehyde concentration. HO-1 mRNA expression was examined with real-time PCR. The extent of DNA damage was determined by the alkaline-labile comet assay. A potential pro-apoptotic quercetin action was determined using the FITC-Annexin V kit. The quercetin and isorhamnetin concentrations in serum were analyzed by HPLC-ECD. MDA concentration and FRAP values, were significantly decreased in the spleen and bone marrow cells of rats treated with quercetin, in a dose of 80mg/kg b.w. in comparison with the control rats; no significant changes were observed after quercetin was administered in a dose ten times as low. Treatment with quercetin dose-dependently upregulated the expression of HO-1 mRNA in the bone marrow cells. Quercetin administration to the rats did not induce either DNA damage or apoptosis in the examined cells. The results of our study prove that changes in the antioxidant state, caused by quercetin, do not lead to DNA damage or exert any pro-apoptotic activity in vivo.", "title": "The changes of antioxidant defense system caused by quercetin administration do not lead to DNA damage and apoptosis in the spleen and bone marrow cells of rats." }, { "docid": "14848619", "text": "Hypoxia is a common cause of cell death and is implicated in many disease processes including stroke and chronic degenerative disorders. In response to hypoxia, cells express a variety of genes, which allow adaptation to altered metabolic demands, decreased oxygen demands, and the removal of irreversibly damaged cells. Using polymerase chain reaction–based suppression subtractive hybridization to find genes that are differentially expressed in hypoxia, we identified the BH3-only Bcl-2 family protein Noxa. Noxa is a candidate molecule mediating p53-induced apoptosis. We show that Noxa promoter responds directly to hypoxia via hypoxia-inducible factor (HIF)-1α. Suppression of Noxa expression by antisense oligonucleotides rescued cells from hypoxia-induced cell death and decreased infarction volumes in an animal model of ischemia. Further, we show that reactive oxygen species and resultant cytochrome c release participate in Noxa-mediated hypoxic cell death. Altogether, our results show that Noxa is induced by HIF-1α and mediates hypoxic cell death.", "title": "BH3-only Protein Noxa Is a Mediator of Hypoxic Cell Death Induced by Hypoxia-inducible Factor 1α" }, { "docid": "35962023", "text": "Recent studies suggest a close relationship between cell metabolism and apoptosis. We have evaluated changes in lipid metabolism on permeabilized hepatocytes treated with truncated Bid (tBid) in the presence of caspase inhibitors and exogenous cytochrome c. The measurement of β-oxidation flux by labeled palmitate demonstrates that tBid inhibits β-oxidation, thereby resulting in the accumulation of palmitoyl-coenzyme A (CoA) and depletion of acetyl-carnitine and acylcarnitines, which is pathognomonic for inhibition of carnitine palmitoyltransferase-1 (CPT-1). We also show that tBid decreases CPT-1 activity by a mechanism independent of both malonyl-CoA, the key inhibitory molecule of CPT-1, and Bak and/or Bax, but dependent on cardiolipin decrease. Overexpression of Bcl-2, which is able to interact with CPT-1, counteracts the effects exerted by tBid on β-oxidation. The unexpected role of tBid in the regulation of lipid β-oxidation suggests a model in which tBid-induced metabolic decline leads to the accumulation of toxic lipid metabolites such as palmitoyl-CoA, which might become participants in the apoptotic pathway.", "title": "tBid induces alterations of mitochondrial fatty acid oxidation flux by malonyl-CoA-independent inhibition of carnitine palmitoyltransferase-1" } ]

[ { "docid": "7821634", "text": "Neoadjuvant chemotherapy (NAC) induces a pathological complete response (pCR) in ∼30% of patients with breast cancer. However, many patients have residual cancer after chemotherapy, which correlates with a higher risk of metastatic recurrence and poorer outcome than those who achieve a pCR. We hypothesized that molecular profiling of tumors after NAC would identify genes associated with drug resistance. Digital transcript counting was used to profile surgically resected breast cancers after NAC. Low concentrations of dual specificity protein phosphatase 4 (DUSP4), an ERK phosphatase, correlated with high post-NAC tumor cell proliferation and with basal-like breast cancer (BLBC) status. BLBC had higher DUSP4 promoter methylation and gene expression patterns of Ras-ERK pathway activation relative to other breast cancer subtypes. DUSP4 overexpression increased chemotherapy-induced apoptosis, whereas DUSP4 depletion dampened the response to chemotherapy. Reduced DUSP4 expression in primary tumors after NAC was associated with treatment-refractory high Ki-67 scores and shorter recurrence-free survival. Finally, inhibition of mitogen-activated protein kinase kinase (MEK) synergized with docetaxel treatment in BLBC xenografts. Thus, DUSP4 downregulation activates the Ras-ERK pathway in BLBC, resulting in an attenuated response to anti-cancer chemotherapy.", "title": "Profiling of residual breast cancers after neoadjuvant chemotherapy identifies DUSP4 deficiency as a mechanism of drug resistance" } ]

[ { "docid": "28651643", "text": "Activating mutations within the K-ras gene occur in a high percentage of human pancreatic carcinomas. We reported previously that the presence of oncogenic, activated K-ras in human pancreatic carcinoma cell lines did not result in constitutive activation of the extracellular signal-regulated kinases (ERK1 and ERK2). In the present study, we further characterized the ERK signaling pathway in pancreatic tumor cell lines in order to determine whether the ERK pathway is subject to a compensatory downregulation. We found that the attenuation of serum-induced ERK activation was not due to a delay in the kinetics of ERK phosphorylation. Treatment with the tyrosine phosphatase inhibitor orthovanadate increased the level of ERK phosphorylation, implicating a vanadate-sensitive tyrosine phosphatase in the negative regulation of ERK. Furthermore, expression of a dual specificity phosphatase capable of inactivating ERK known as mitogen-activated protein (MAP) kinase phosphatase-2 (MKP-2) was elevated in most of the pancreatic tumor cell lines and correlated with the presence of active MAP kinase kinase (MEK). Taken together, these results suggest that pancreatic tumor cells expressing oncogenic K-ras compensate, in part, by upregulating the expression of MKP-2 to repress the ERK signaling pathway.", "title": "Pancreatic tumor cells with mutant K-ras suppress ERK activity by MEK-dependent induction of MAP kinase phosphatase-2." }, { "docid": "85665741", "text": "5247 Constitutive ERK signaling is common in human cancer and is often the result of activating mutations of BRAF, RAS and upstream receptor tyrosine kinases. Missense BRAF kinase domain mutations are frequently observed in melanoma, colon and thyroid cancers and less frequently in lung and other cancer types. The vast majority (>90%) involve a glutamic acid for valine substitution at codon 600 (V600E), which results in elevated BRAF kinase activity. BRAF kinase domain mutations with intermediate and impaired kinase activity have also been identified, most frequently in NSCLC. We have previously reported that tumors with V600E BRAF mutation are selectively sensitive to MEK inhibition. Using the potent and selective MEK1/2 inhibitor PD0325901 (Pfizer), we examined a panel of NSCLC cell lines with mutant EGFR, KRAS, and/or low, intermediate and high-activity BRAF kinase domain mutations for MEK dependence. In all but one case, EGFR, KRAS and BRAF mutations were mutually exclusive with the exception being a cell line with concurrent NRAS and intermediate activity BRAF mutations. Consistent with our prior results, NSCLC cells with V600E BRAF mutation were exquisitely sensitive to MEK inhibition (PD0325901 IC50 of 2nM). The proliferation of cells with non-V600E mutations, including those with high (G469A), intermediate (L597V) and impaired (G466V) kinase activities, was also MEK dependent with IC50’s ranging between 2.7 and 80 nM. Inhibition of MEK in these cells resulted in downregulation of cyclin D1 and G1 growth arrest, with variable induction of apoptosis. Despite high basal ERK activity, NSCLC tumor cells with EGFR mutation were uniformly resistant to MEK inhibition (at doses of up to 500nM), despite effective and prolonged inhibition of ERK phosphorylation. Tumor cells with RAS mutation had a more variable response, with some cell lines demonstrating sensitivity, while others were completely resistant. There was no correlation between basal ERK activity and sensitivity to MEK inhibition. A strong inverse correlation between Akt activity and PD0325901 sensitivity was observed. These results suggest that MEK inhibition may be useful therapeutically in tumors with V600E and non-V600E BRAF kinase domain mutations. The results also suggest that inhibition of both MEK and Akt signaling may be required in NSCLC tumors with high basal AKT activity.", "title": "BRAF mutation predicts for MEK-dependence in non-small cell lung cancer (NSCLC)." }, { "docid": "10279084", "text": "MAP kinase phosphatase-2 (MKP-2) is a member of the family of dual specificity phosphatases that functions to inactivate the ERK and JNK MAP kinase signalling pathways. Here, we identify a novel human MKP-2 variant (MKP-2-S) lacking the MAP kinase binding site but retaining the phosphatase catalytic domain. Endogenous MKP-2-S transcripts and proteins were found in PC3 prostate and MDA-MB-231 breast cancer cells and also human prostate biopsies. Cellular transfection of MKP-2-S gave rise to a nuclear protein of 33kDa which displayed phosphatase activity comparable to the formerly described long form of MKP-2 (MKP-2-L). Due to its lack of a kinase interacting motif (KIM), MKP-2-S did not bind to JNK or ERK; MKP-2-L bound ERK and to a lesser extent JNK. Protein turnover of adenoviral expressed MKP-2-S was accelerated relative to MKP-2-L, with a greater susceptibility to proteosomal-mediated degradation. MKP-2-S retained its ability to deactivate JNK in a similar manner as MKP-2-L and was an effective inhibitor of LPS-stimulated COX-2 induction. However, unlike MKP-2-L, MKP-2-S was unable to reverse serum-induced ERK activation or significantly inhibit endothelial cell proliferation. These findings reveal the occurrence of a novel splice variant of MKP-2 which is unable to bind ERK and may be significant in the dysregulation of MAP kinase activity in certain disease states, particularly in breast and prostate cancers.", "title": "Differential regulation of MAP kinase activation by a novel splice variant of human MAP kinase phosphatase-2." }, { "docid": "9225850", "text": "Neutrophils are peripheral blood leukocytes that represent the first line of immune cell defense against bacterial and fungal infections but are also crucial players in the generation of the inflammatory response. Many neutrophil cell surface receptors regulate important cellular processes via activation of agonist-activated PI3Ks. We show here that activation of human neutrophils with insoluble immune complexes drives a previously uncharacterized, PI3K-dependent, non-canonical, pro-apoptotic signaling pathway, FcγR-PI3Kβ/δ-Cdc42-Pak-Mek-Erk. This is a rare demonstration of Ras/Raf-independent activation of Erk and of PI3K-mediated activation of Cdc42. In addition, comparative analysis of immune-complex- and fMLF-induced signaling uncovers key differences in pathways used by human and murine neutrophils. The non-canonical pathway we identify in this study may be important for the resolution of inflammation in chronic inflammatory diseases that rely on immune-complex-driven neutrophil activation.", "title": "Non-canonical PI3K-Cdc42-Pak-Mek-Erk Signaling Promotes Immune-Complex-Induced Apoptosis in Human Neutrophils" }, { "docid": "4920376", "text": "Induction of compensatory mechanisms and ERK reactivation has limited the effectiveness of Raf and MEK inhibitors in RAS-mutant cancers. We determined that direct pharmacologic inhibition of ERK suppressed the growth of a subset of KRAS-mutant pancreatic cancer cell lines and that concurrent phosphatidylinositol 3-kinase (PI3K) inhibition caused synergistic cell death. Additional combinations that enhanced ERK inhibitor action were also identified. Unexpectedly, long-term treatment of sensitive cell lines caused senescence, mediated in part by MYC degradation and p16 reactivation. Enhanced basal PI3K-AKT-mTOR signaling was associated with de novo resistance to ERK inhibitor, as were other protein kinases identified by kinome-wide siRNA screening and a genetic gain-of-function screen. Our findings reveal distinct consequences of inhibiting this kinase cascade at the level of ERK.", "title": "Long-Term ERK Inhibition in KRAS-Mutant Pancreatic Cancer Is Associated with MYC Degradation and Senescence-like Growth Suppression." }, { "docid": "4729644", "text": "The long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) was reported to be upregulated and be involved in oncogenic growth and drug resistance in nasopharyngeal carcinoma (NPC). However, the exact roles of NEAT1 and its underlying mechanisms in the drug resistance of NPC remain largely unclear. In this study, the expressions of NEAT1, let-72-5p and Rsf-1 mRNA were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The effects of NEAT1 and let-72-5p on cell proliferation and cisplatin resistance of NPC cells were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and 5-ethynyl-20-deoxyuridine (EdU) assay. Western blot analysis was performed to detect the protein levels of Rsf-1, Ras, p-Raf1, Raf1, p-MEK1, MEK1, p-ERK1/2 and ERK1/2. Xenograft tumor assay was done to elucidate the role of NEAT1 involved in NPC tumor growth in vivo. We found that NEAT1 was upregulated and let-7a-5p was downregulated in NPC tissues, as well as NPC cell lines. Inhibition of NEAT1 markedly repressed the cisplatin resistance of NPC cells. NEAT1 was demonstrated to interact with let-7a-5p. Besides, a negative correlation between NEAT1 and let-7a-5p expression was observed in NPC tissues. Rsf-1 was confirmed as a target of let-7a-5p. NEAT1 remarkably reversed the inhibitory effect of let-7q-5p on the cisplatin resistance of NPC cells in vitro. Additionally, NEAT1 knockdown inhibited the Ras-MAPK pathway in NPC cells. NEAT1 knockdown suppressed tumor growth in the presence of cisplatin in vivo. Overall, these findings suggest that NEAT1/let-7a-5p axis regulates the cisplatin resistance in NPC by targeting Rsf-1 and modulating the Ras-MAPK signaling pathway.", "title": "LncRNA NEAT1/let-7a-5p axis regulates the cisplatin resistance in nasopharyngeal carcinoma by targeting Rsf-1 and modulating the Ras-MAPK pathway." }, { "docid": "2272614", "text": "Activating mutations in the EGF receptor (EGFR) are associated with clinical responsiveness to EGFR tyrosine kinase inhibitors (TKI), such as erlotinib and gefitinib. However, resistance eventually arises, often due to a second EGFR mutation, most commonly T790M. Through a genome-wide siRNA screen in a human lung cancer cell line and analyses of murine mutant EGFR-driven lung adenocarcinomas, we found that erlotinib resistance was associated with reduced expression of neurofibromin, the RAS GTPase-activating protein encoded by the NF1 gene. Erlotinib failed to fully inhibit RAS-ERK signaling when neurofibromin levels were reduced. Treatment of neurofibromin-deficient lung cancers with a MAP-ERK kinase (MEK) inhibitor restored sensitivity to erlotinib. Low levels of NF1 expression were associated with primary and acquired resistance of lung adenocarcinomas to EGFR TKIs in patients. These findings identify a subgroup of patients with EGFR-mutant lung adenocarcinoma who might benefit from combination therapy with EGFR and MEK inhibitors.", "title": "Reduced NF1 expression confers resistance to EGFR inhibition in lung cancer." }, { "docid": "10450725", "text": "BACKGROUND/AIMS The small GTPase of Ras and Rho families are widely involved in human tumorgenesis and metastasis. It has recently been reported that pamidronate inhibits the mevalonate pathway, which is required for the prenylation of the small GTPase. We demonstrated a possible beneficial use of pamidronate in the treatment of hepatocellular carcinoma (HCC). \n METHODS The effect of pamidronate on cell proliferation was analyzed with five hepatoma cell lines using MTT assay. Apoptosis was evaluated by staining with DAPI and a histon ELISA assay. A cell migration assay was performed using the Modified Boyden Chamber. To analyze anti-proliferation effect of pamidronate in vivo, tumor volumes were monitored with the intraperitoneal injection of pamidronate after subcutaneous inoculation of PLC/PRF/5 cells into nude mice. \n RESULTS Pamidronate inhibited cell growth for all hepatoma cell lines. The amount of membrane associated Ras and phosphorylated extracellular signal-regulated kinase 2 (ERK 2) were reduced after pamidronate treatment. Pamidronate increased apoptosis and cleavage of Caspase-3, and -9. Pamidronate suppressed membrane associated RhoA and cell motility. In vivo, tumor volumes were significantly suppressed by pamidronate at three weeks (P<0.03). \n CONCLUSIONS We conclude that pamidronate has therapeutic potential in inducing anti-proliferative, apoptotic, and anti-migratory effects in HCC.", "title": "Pamidronate induced anti-proliferative, apoptotic, and anti-migratory effects in hepatocellular carcinoma." }, { "docid": "24190159", "text": "Mutations of the KRAS oncogene are predictive for resistance to treatment with antibodies against the epithelial growth factor receptor in patients with colorectal cancer. Overcoming this therapeutic dilemma could potentially be achieved by the introduction of drugs that inhibit signaling pathways that are activated by KRAS mutations. To identify comprehensively such signaling pathways, we profiled pretreatment biopsies and normal mucosa from 65 patients with locally advanced rectal cancer-30 of which carried mutated KRAS-using global gene expression microarrays. By comparing all tumor tissues exclusively to matched normal mucosa, we could improve assay sensitivity, and identified a total of 22,297 features that were differentially expressed (adjusted P-value <0.05) between normal mucosa and cancer, including several novel potential rectal cancer genes. We then used this comprehensive description of the rectal cancer transcriptome as the baseline for identifying KRAS-dependent alterations. The presence of activating KRAS mutations is significantly correlated to an upregulation of 13 genes (adjusted P-value <0.05), among them DUSP4, a MAP-kinase phosphatase, and SMYD3, a histone methyltransferase. Inhibition of the expression of both genes has previously been shown using the MEK1-inhibitor PD98059 and the antibacterial compound Novobiocin, respectively. These findings suggest a potential approach to overcome resistance to treatment with antibodies against the epithelial growth factor receptor in patients with KRAS-mutant rectal carcinomas.", "title": "Mutated KRAS results in overexpression of DUSP4, a MAP-kinase phosphatase, and SMYD3, a histone methyltransferase, in rectal carcinomas." }, { "docid": "10991183", "text": "How individual cells respond to mechanical forces is of considerable interest to biologists as force affects many aspects of cell behaviour. The application of force on integrins triggers cytoskeletal rearrangements and growth of the associated adhesion complex, resulting in increased cellular stiffness, also known as reinforcement. Although RhoA has been shown to play a role during reinforcement, the molecular mechanisms that regulate its activity are unknown. By combining biochemical and biophysical approaches, we identified two guanine nucleotide exchange factors (GEFs), LARG and GEF-H1, as key molecules that regulate the cellular adaptation to force. We show that stimulation of integrins with tensional force triggers activation of these two GEFs and their recruitment to adhesion complexes. Surprisingly, activation of LARG and GEF-H1 involves distinct signalling pathways. Our results reveal that LARG is activated by the Src family tyrosine kinase Fyn, whereas GEF-H1 catalytic activity is enhanced by ERK downstream of a signalling cascade that includes FAK and Ras.", "title": "The Rho GEFs LARG and GEF-H1 regulate the mechanical response to force on integrins" }, { "docid": "33030946", "text": "Summary Hypoxia augments inflammatory responses and osteoclastogenesis by incompletely understood mechanisms. We identified COMMD1 as a cell‐intrinsic negative regulator of osteoclastogenesis that is suppressed by hypoxia. In human macrophages, COMMD1 restrained induction of NF‐&kgr;B signaling and a transcription factor E2F1‐dependent metabolic pathway by the cytokine RANKL. Downregulation of COMMD1 protein expression by hypoxia augmented RANKL‐induced expression of inflammatory and E2F1 target genes and downstream osteoclastogenesis. E2F1 targets included glycolysis and metabolic genes including CKB that enabled cells to meet metabolic demands in challenging environments, as well as inflammatory cytokine‐driven target genes. Expression quantitative trait locus analysis linked increased COMMD1 expression with decreased bone erosion in rheumatoid arthritis. Myeloid deletion of Commd1 resulted in increased osteoclastogenesis in arthritis and inflammatory osteolysis models. These results identify COMMD1 and an E2F‐metabolic pathway as key regulators of osteoclastogenic responses under pathological inflammatory conditions and provide a mechanism by which hypoxia augments inflammation and bone destruction. Graphical Abstract Figure. No Caption available. HighlightsCOMMD1 is a negative regulator of osteoclast differentiationCOMMD1 suppresses bone loss in RA and inflammatory arthritis and osteolysis modelsCOMMD1 negatively regulates E2F1‐dependent metabolic pathways in macrophagesHypoxia suppresses COMMD1 expression to augment osteoclastogenesis &NA; Pathways that promote osteoclastogenesis are well characterized but less is known about negative regulators that suppress pathological bone loss. Murata et al. identify COMMD1 as an inhibitor of osteoclastogenesis that restrains NF‐&kgr;B‐ and E2F1‐CKB‐mediated metabolic pathways in macrophages.", "title": "Hypoxia‐Sensitive COMMD1 Integrates Signaling and Cellular Metabolism in Human Macrophages and Suppresses Osteoclastogenesis" }, { "docid": "11200685", "text": "Microtubule nucleation is an essential step in the formation of the microtubule cytoskeleton. We recently showed that androgen and Src promote microtubule nucleation and γ-tubulin accumulation at the centrosome. Here, we explore the mechanisms by which androgen and Src regulate these processes and ask whether integrins play a role. We perturb integrin function by a tyrosine-to-alanine substitution in membrane-proximal NPIY motif in the integrin β1 tail and show that this mutant substantially decreases microtubule nucleation and γ-tubulin accumulation at the centrosome. Because androgen stimulation promotes the interaction of the androgen receptor with Src, resulting in PI3K/AKT and MEK/ERK signaling, we asked whether these pathways are inhibited by the mutant integrin and whether they regulate microtubule nucleation. Our results indicate that the formation of the androgen receptor-Src complex and the activation of downstream pathways are significantly suppressed when cells are adhered by the mutant integrin. Inhibitor studies indicate that microtubule nucleation requires MEK/ERK but not PI3K/AKT signaling. Importantly, the expression of activated RAF-1 is sufficient to rescue microtubule nucleation inhibited by the mutant integrin by promoting the centrosomal accumulation of γ-tubulin. Our data define a novel paradigm of integrin signaling, where integrins regulate microtubule nucleation by promoting the formation of androgen receptor-Src signaling complexes to activate the MEK/ERK signaling pathway.", "title": "Integrins regulate microtubule nucleating activity of centrosome through mitogen-activated protein kinase/extracellular signal-regulated kinase kinase/extracellular signal-regulated kinase (MEK/ERK) signaling." }, { "docid": "14819804", "text": "The novel phosphatidylinositol-3-kinase (PI3K) inhibitor PX-866 was tested against 13 experimental human tumor xenografts derived from cell lines of various tissue origins. Mutant PI3K (PIK3CA) and loss of PTEN activity were sufficient, but not necessary, as predictors of sensitivity to the antitumor activity of the PI3K inhibitor PX-866 in the presence of wild-type Ras, whereas mutant oncogenic Ras was a dominant determinant of resistance, even in tumors with coexisting mutations in PIK3CA. The level of activation of PI3K signaling measured by tumor phosphorylated Ser(473)-Akt was insufficient to predict in vivo antitumor response to PX-866. Reverse-phase protein array revealed that the Ras-dependent downstream targets c-Myc and cyclin B were elevated in cell lines resistant to PX-866 in vivo. Studies using an H-Ras construct to constitutively and preferentially activate the three best-defined downstream targets of Ras, i.e., Raf, RalGDS, and PI3K, showed that mutant Ras mediates resistance through its ability to use multiple pathways for tumorigenesis. The identification of Ras and downstream signaling pathways driving resistance to PI3K inhibition might serve as an important guide for patient selection as inhibitors enter clinical trials and for the development of rational combinations with other molecularly targeted agents.", "title": "Mutations in the phosphatidylinositol-3-kinase pathway predict for antitumor activity of the inhibitor PX-866 whereas oncogenic Ras is a dominant predictor for resistance." }, { "docid": "5321708", "text": "Cytokinesis is the final stage in cell division. Although integrins can regulate cytokinesis, the mechanisms involved are not fully understood. In this study, we demonstrate that integrin-regulated ERK (extracellular signal-related kinase) and RSK (p90 ribosomal S6 kinase) signaling promotes successful cytokinesis. Inhibiting the activation of ERK and RSK in CHO cells by a mutation in the integrin β1 cytoplasmic tail or with pharmacological inhibitors results in the accumulation of cells with midbodies and the formation of binucleated cells. Activation of ERK and RSK signaling by the expression of constitutively active RAF1 suppresses the mutant phenotype in a RSK-dependent manner. Constitutively active RSK2 also restores cytokinesis inhibited by the mutant integrin. Importantly, the regulatory role of the RSK pathway is not specific to CHO cells. MCF-10A human mammary epithelial cells and HPNE human pancreatic ductal epithelial cells exhibit a similar dependence on RSK for successful cytokinesis. In addition, depriving mitotic MCF10A cells of integrin-mediated adhesion by incubating them in suspension suppressed ERK and RSK activation and resulted in a failure of cytokinesis. Furthermore, inhibition of RSK or integrins within the 3D context of a developing salivary gland organ explant also leads to an accumulation of epithelial cells with midbodies, suggesting a similar defect in cytokinesis. Interestingly, neither ERK nor RSK regulates cytokinesis in human fibroblasts, suggesting cell-type specificity. Taken together, our results identify the integrin-RSK signaling axis as an important regulator of cytokinesis in epithelial cells. We propose that the proper interaction of cells with their microenvironment through integrins contributes to the maintenance of genomic stability by promoting the successful completion of cytokinesis.", "title": "Integrins promote cytokinesis through the RSK signaling axis." }, { "docid": "4452659", "text": "Macroautophagy (hereafter referred to as autophagy) is a catabolic membrane trafficking process that degrades a variety of cellular constituents and is associated with human diseases. Although extensive studies have focused on autophagic turnover of cytoplasmic materials, little is known about the role of autophagy in degrading nuclear components. Here we report that the autophagy machinery mediates degradation of nuclear lamina components in mammals. The autophagy protein LC3/Atg8, which is involved in autophagy membrane trafficking and substrate delivery, is present in the nucleus and directly interacts with the nuclear lamina protein lamin B1, and binds to lamin-associated domains on chromatin. This LC3-lamin B1 interaction does not downregulate lamin B1 during starvation, but mediates its degradation upon oncogenic insults, such as by activated RAS. Lamin B1 degradation is achieved by nucleus-to-cytoplasm transport that delivers lamin B1 to the lysosome. Inhibiting autophagy or the LC3-lamin B1 interaction prevents activated RAS-induced lamin B1 loss and attenuates oncogene-induced senescence in primary human cells. Our study suggests that this new function of autophagy acts as a guarding mechanism protecting cells from tumorigenesis.", "title": "Autophagy mediates degradation of nuclear lamina" }, { "docid": "17223891", "text": "NLRP12 is a member of the intracellular Nod-like receptor (NLR) family that has been suggested to downregulate the production of inflammatory cytokines, but its physiological role in regulating inflammation has not been characterized. We analyzed mice deficient in Nlrp12 to study its role in inflammatory diseases such as colitis and colorectal tumorigenesis. We show that Nlrp12-deficient mice are highly susceptible to colon inflammation and tumorigenesis, which is associated with increased production of inflammatory cytokines, chemokines, and tumorigenic factors. Enhanced colon inflammation and colorectal tumor development in Nlrp12-deficient mice are due to a failure to dampen NF-κB and ERK activation in macrophages. These results reveal a critical role for NLRP12 in maintaining intestinal homeostasis and providing protection against colorectal tumorigenesis.", "title": "The NOD-like receptor NLRP12 attenuates colon inflammation and tumorigenesis." }, { "docid": "8210189", "text": "Ras proteins in budding yeasts initially appeared to regulate initiation of the cell cycle in response to nutrient availability. More recent work, while clarifying the mechanism of Ras-mediated signal transduction, has undermined our notion of the signal Ras transmits. We now suspect that Ras helps to coordinate cellular metabolism and mass accumulation, but what Ras responds to is not clear.", "title": "RAS genes in Saccharomyces cerevisiae: signal transduction in search of a pathway." }, { "docid": "38143689", "text": "Serotonin 5-HT2C receptors (5-HT(2C)Rs) are almost exclusively expressed in the CNS, and implicated in disorders such as obesity, depression, and schizophrenia. The present study investigated the mechanisms governing the coupling of the 5-HT(2C)R to the extracellular signal-regulated kinases (ERKs) 1/2, using a Chinese hamster ovary (CHO) cell line stably expressing the receptor at levels comparable to those found in the brain. Using the non-RNA-edited isoform of the 5-HT(2C)R, constitutive ERK1/2 phosphorylation was observed and found to be modulated by full, partial and inverse agonists. Interestingly, agonist-directed trafficking of receptor stimulus was also observed when comparing effects on phosphoinositide accumulation and intracellular Ca2+ elevation to ERK1/2 phosphorylation, whereby the agonists, [+/-]-2,5-dimethoxy-4-iodoamphetamine (DOI) and quipazine, showed reversal of efficacy between the phosphoinositide/Ca2+ pathways, on the one hand, and the ERK1/2 pathway on the other. Subsequent molecular characterization found that 5-HT-stimulated ERK1/2 phosphorylation in this cellular background requires phospholipase D, protein kinase C, and activation of the Raf/MEK/ERK module, but is independent of both receptor- and non-receptor tyrosine kinases, phospholipase C, phosphoinositide 3-kinase, and endocytosis. Our findings underscore the potential for exploiting pathway-selective receptor states in the differential modulation of signaling pathways that play prominent roles in normal and abnormal neuronal signaling.", "title": "Characterization of serotonin 5-HT2C receptor signaling to extracellular signal-regulated kinases 1 and 2." }, { "docid": "8453819", "text": "The integrin family of heterodimeric cell-surface receptors are fundamental in cell-cell and cell-matrix adhesion. Changes to either integrin-ligand affinity or integrin gene expression are central to a variety of disease processes, including inflammation, cardiovascular disease and cancer. In screening for novel activators of integrin-ligand affinity we identified the previously uncharacterised multi-transmembrane domain protein Fam38A, located at the endoplasmic reticulum (ER). siRNA knockdown of Fam38A in epithelial cells inactivates endogenous beta1 integrin, reducing cell adhesion. Fam38A mediates integrin activation by recruiting the small GTPase R-Ras to the ER, which activates the calcium-activated protease calpain by increasing Ca(2+) release from cytoplasmic stores. Fam38A-induced integrin activation is blocked by inhibition of either R-Ras or calpain activity, or by siRNA knockdown of talin, a well-described calpain substrate. This highlights a novel mechanism for integrin activation by Fam38A, utilising calpain and R-Ras signalling from the ER. These data represent the first description of a novel spatial regulator of R-Ras, of an alternative integrin activation-suppression pathway based on direct relocalisation of R-Ras to the ER, and of a mechanism linking R-Ras and calpain signalling from the ER with modulation of integrin-ligand affinity.", "title": "Integrin activation by Fam38A uses a novel mechanism of R-Ras targeting to the endoplasmic reticulum." } ]

[ { "docid": "7821634", "text": "Neoadjuvant chemotherapy (NAC) induces a pathological complete response (pCR) in ∼30% of patients with breast cancer. However, many patients have residual cancer after chemotherapy, which correlates with a higher risk of metastatic recurrence and poorer outcome than those who achieve a pCR. We hypothesized that molecular profiling of tumors after NAC would identify genes associated with drug resistance. Digital transcript counting was used to profile surgically resected breast cancers after NAC. Low concentrations of dual specificity protein phosphatase 4 (DUSP4), an ERK phosphatase, correlated with high post-NAC tumor cell proliferation and with basal-like breast cancer (BLBC) status. BLBC had higher DUSP4 promoter methylation and gene expression patterns of Ras-ERK pathway activation relative to other breast cancer subtypes. DUSP4 overexpression increased chemotherapy-induced apoptosis, whereas DUSP4 depletion dampened the response to chemotherapy. Reduced DUSP4 expression in primary tumors after NAC was associated with treatment-refractory high Ki-67 scores and shorter recurrence-free survival. Finally, inhibition of mitogen-activated protein kinase kinase (MEK) synergized with docetaxel treatment in BLBC xenografts. Thus, DUSP4 downregulation activates the Ras-ERK pathway in BLBC, resulting in an attenuated response to anti-cancer chemotherapy.", "title": "Profiling of residual breast cancers after neoadjuvant chemotherapy identifies DUSP4 deficiency as a mechanism of drug resistance" } ]

[ { "docid": "24190159", "text": "Mutations of the KRAS oncogene are predictive for resistance to treatment with antibodies against the epithelial growth factor receptor in patients with colorectal cancer. Overcoming this therapeutic dilemma could potentially be achieved by the introduction of drugs that inhibit signaling pathways that are activated by KRAS mutations. To identify comprehensively such signaling pathways, we profiled pretreatment biopsies and normal mucosa from 65 patients with locally advanced rectal cancer-30 of which carried mutated KRAS-using global gene expression microarrays. By comparing all tumor tissues exclusively to matched normal mucosa, we could improve assay sensitivity, and identified a total of 22,297 features that were differentially expressed (adjusted P-value <0.05) between normal mucosa and cancer, including several novel potential rectal cancer genes. We then used this comprehensive description of the rectal cancer transcriptome as the baseline for identifying KRAS-dependent alterations. The presence of activating KRAS mutations is significantly correlated to an upregulation of 13 genes (adjusted P-value <0.05), among them DUSP4, a MAP-kinase phosphatase, and SMYD3, a histone methyltransferase. Inhibition of the expression of both genes has previously been shown using the MEK1-inhibitor PD98059 and the antibacterial compound Novobiocin, respectively. These findings suggest a potential approach to overcome resistance to treatment with antibodies against the epithelial growth factor receptor in patients with KRAS-mutant rectal carcinomas.", "title": "Mutated KRAS results in overexpression of DUSP4, a MAP-kinase phosphatase, and SMYD3, a histone methyltransferase, in rectal carcinomas." }, { "docid": "238409", "text": "Background:Chronic cyclosporine A (CsA) nephrotoxicity (CCN) is a major cause of chronic renal dysfunction and has no effective clinical interventions yet. Objective: To reveal the mechanisms of renal cell apoptosis in CCN, we analyzed all in vitro studies of such mechanisms. Methods: We collected all in vitro studies about the mechanisms of renal cell apoptosis induced by CsA in Medline (1966 to July 2010), Embase (1980 to July 2010) and ISI (1986 to July 2010), evaluated their quality according to in vitro standards and extracted data following the PICOS principles and synthesized the data. Results: First,CsA could upregulate Fas and Fas-L expression, increase FADD and apoptosis enzymes (caspase-2, -3, -4, -7, -8, -9 and -10) and downregulate the Bcl-2 and Bcl-xL. Second, CsA could induce oxidative stress and damage the antioxidant defense system. Third, CsA could increase the expression of HERP, GRP78 and CHOP. Fourth, CsA could induce renal cell apoptosis and increase their iNOS and p53 expression in cultured cells. Conclusions: At least four pathways are involved in renal cell apoptosis induced by CsA in different cell species. Caspases might be their final common pathway in vitro. They might all provide potential points for interventions, but these need to be confirmed in vivo.", "title": "Mechanisms of Renal Cell Apoptosis Induced by Cyclosporine A: A Systematic Review of in vitro Studies" }, { "docid": "23403754", "text": "In this review I summarize interrelations between bioenergetic processes and such programmed death phenomena as cell suicide (apoptosis and necrosis) and mitochondrial suicide (mitoptosis). The following conclusions are made. (I) ATP and rather often mitochondrial hyperpolarization (i.e. an increase in membrane potential, ΔΨ) are required for certain steps of apoptosis and necrosis. (II) Apoptosis, even if it is accompanied by ΔΨ and [ATP] increases at its early stage, finally results in a ΔΨ collapse and ATP decrease. (III) Moderate (about three-fold) lowering of [ATP] for short and long periods of time induces apoptosis and necrosis, respectively. In some types of apoptosis and necrosis, the cell death is mediated by a ΔΨ-dependent overproduction of ROS by the initial (Complex I) and the middle (Complex III) spans of the respiratory chain. ROS initiate mitoptosis which is postulated to rid the intracellular population of mitochondria from those that are ROS overproducing. Massive mitoptosis can result in cell death due to release to cytosol of the cell death proteins normally hidden in the mitochondrial intermembrane space.", "title": "Bioenergetic aspects of apoptosis, necrosis and mitoptosis" }, { "docid": "25510546", "text": "Increased lipid supply causes beta cell death, which may contribute to reduced beta cell mass in type 2 diabetes. We investigated whether endoplasmic reticulum (ER) stress is necessary for lipid-induced apoptosis in beta cells and also whether ER stress is present in islets of an animal model of diabetes and of humans with type 2 diabetes. Expression of genes involved in ER stress was evaluated in insulin-secreting MIN6 cells exposed to elevated lipids, in islets isolated from db/db mice and in pancreas sections of humans with type 2 diabetes. Overproduction of the ER chaperone heat shock 70 kDa protein 5 (HSPA5, previously known as immunoglobulin heavy chain binding protein [BIP]) was performed to assess whether attenuation of ER stress affected lipid-induced apoptosis. We demonstrated that the pro-apoptotic fatty acid palmitate triggers a comprehensive ER stress response in MIN6 cells, which was virtually absent using non-apoptotic fatty acid oleate. Time-dependent increases in mRNA levels for activating transcription factor 4 (Atf4), DNA-damage inducible transcript 3 (Ddit3, previously known as C/EBP homologous protein [Chop]) and DnaJ homologue (HSP40) C3 (Dnajc3, previously known as p58) correlated with increased apoptosis in palmitate- but not in oleate-treated MIN6 cells. Attenuation of ER stress by overproduction of HSPA5 in MIN6 cells significantly protected against lipid-induced apoptosis. In islets of db/db mice, a variety of marker genes of ER stress were also upregulated. Increased processing (activation) of X-box binding protein 1 (Xbp1) mRNA was also observed, confirming the existence of ER stress. Finally, we observed increased islet protein production of HSPA5, DDIT3, DNAJC3 and BCL2-associated X protein in human pancreas sections of type 2 diabetes subjects. Our results provide evidence that ER stress occurs in type 2 diabetes and is required for aspects of the underlying beta cell failure.", "title": "Endoplasmic reticulum stress contributes to beta cell apoptosis in type 2 diabetes" }, { "docid": "37444589", "text": "Although 13 years have passed since identification of human immunodeficiency virus-1 (HIV-1) as the cause of AIDS, we do not yet know how HIV kills its primary target, the T cell that carries the CD4 antigen. We and others have shown an increase in the percentage of apoptotic cells among circulating CD4+ (and CD8+) T cells of HIV-seropositive individuals and an increase in frequency of apoptosis with disease progression. However, it is not known if this apoptosis occurs in infected or uninfected T cells. We show here, using in situ labelling of lymph nodes from HIV-infected children and SIV-infected macaques, that apoptosis occurs predominantly in bystander cells and not in the productively infected cells themselves. These data have implications for pathogenesis and therapy, namely, arguing that rational drug therapy may involve combination agents targeting viral replication in infected cells and apoptosis of uninfected cells.", "title": "Apoptosis occurs predominantly in bystander cells and not in productively infected cells of HIV- and SIV-infected lymph nodes" }, { "docid": "7465900", "text": "BACKGROUND & AIMS Helicobacter pylori-induced gastric epithelial cell (GEC) apoptosis is a complex process that includes activation of the tumor suppressor p53. p53-mediated apoptosis involves p53 activation, bax transcription, and cytochrome c release from mitochondria. Apurinic/apyrimidinic endonuclease-1 (APE-1) regulates transcriptional activity of p53, and H pylori induce APE-1 expression in human GECs. H pylori infection increases intracellular calcium ion concentration [Ca2+]i of GECs, which induces APE-1 acetylation. We investigated the effects of H pylori infection and APE-1 acetylation on GEC apoptosis. \n METHODS AGS cells (wild-type or with suppressed APE-1), KATO III cells, and cells isolated from gastric biopsy specimens were infected with H pylori. Effects were examined by immunoblotting, real-time reverse-transcription polymerase chain reaction, immunoprecipitation, immunofluorescence microscopy, chromatin immunoprecipitation, mobility shift, DNA binding, and luciferase assays. \n RESULTS H pylori infection increased [Ca2+]i and acetylation of APE-1 in GECs, but the acetylation status of APE-1 did not affect the transcriptional activity of p53. In GECs, expression of a form of APE-1 that could not be acetylated increased total and mitochondrial levels of Bax and induced release of cytochrome c and fragmentation of DNA; expression of wild-type APE-1 reduced these apoptotic events. We identified a negative calcium response element in the human bax promoter and found that poly (adenosine diphosphate-ribose) polymerase 1 recruited the acetylated APE-1/histone deacetylase-1 repressor complex to bax nCaRE. \n CONCLUSIONS H pylori-mediated acetylation of APE-1 suppresses Bax expression; this prevents p53-mediated apoptosis when H pylori infect GECs.", "title": "Acetylation of apurinic/apyrimidinic endonuclease-1 regulates Helicobacter pylori-mediated gastric epithelial cell apoptosis." }, { "docid": "23887844", "text": "Neurons and cancer cells use glucose extensively, yet the precise advantage of this adaptation remains unclear. These two seemingly disparate cell types also show an increased regulation of the apoptotic pathway, which allows for their long-term survival. Here we show that both neurons and cancer cells strictly inhibit cytochrome c-mediated apoptosis by a mechanism dependent on glucose metabolism. We report that the pro-apoptotic activity of cytochrome c is influenced by its redox state and that increases in reactive oxygen species (ROS) following an apoptotic insult lead to the oxidation and activation of cytochrome c. In healthy neurons and cancer cells, however, cytochrome c is reduced and held inactive by intracellular glutathione (GSH), generated as a result of glucose metabolism by the pentose phosphate pathway. These results uncover a striking similarity in apoptosis regulation between neurons and cancer cells and provide insight into an adaptive advantage offered by the Warburg effect for cancer cell evasion of apoptosis and for long-term neuronal survival.", "title": "Glucose Metabolism Inhibits Apoptosis in Neurons and Cancer Cells by Redox Inactivation of Cytochrome c" }, { "docid": "5254463", "text": "Colorectal cancer is one of the major causes of cancer-related deaths. To gain further insights into the mechanisms underlying its development, we investigated the role of Wip1 phosphatase, which is highly expressed in intestinal stem cells, in the mouse model of APC(Min)-driven polyposis. We found that Wip1 removal increased the life span of APC(Min) mice through a significant suppression of polyp formation. This protection was dependent on the p53 tumor suppressor, which plays a putative role in the regulation of apoptosis of intestinal stem cells. Activation of apoptosis in stem cells of Wip1-deficient mice, but not wild-type APC(Min) mice, increased when the Wnt pathway was constitutively activated. We propose, therefore, that the Wip1 phosphatase regulates homeostasis of intestinal stem cells. In turn, Wip1 loss suppresses APC(Min)-driven polyposis by lowering the threshold for p53-dependent apoptosis of stem cells, thus preventing their conversion into tumor-initiating stem cells.", "title": "Wip1 phosphatase regulates p53-dependent apoptosis of stem cells and tumorigenesis in the mouse intestine." }, { "docid": "41646286", "text": "Effects of folate deficiency on the rate of apoptosis in human cytotrophoblastic cells has been investigated. Apoptosis was determined in cytotrophoblastic cells after culture in 1. control medium, 2. folate-free medium and 3. folate-free medium plus 10% fetal calf serum. Apoptosis rates in cells cultured in mediums 2 and 3 were significantly higher than those cultured in the control medium (P<0.02 and P<0.03, respectively). In conclusion, human cytotrophoblastic cells show a significantly increased rate of apoptosis in vitro after culture in a folate-free medium. Possible explanations for the association between folate deficiency and pregnancy complications are suggested.", "title": "Folate affects apoptosis in human trophoblastic cells." }, { "docid": "10015292", "text": "Highly regenerative tissues such as blood must possess effective DNA damage responses (DDR) that balance long-term regeneration with protection from leukemogenesis. Hematopoietic stem cells (HSCs) sustain life-long blood production, yet their response to DNA damage remains largely unexplored. We report that human HSCs exhibit delayed DNA double-strand break rejoining, persistent gammaH2AX foci, and enhanced p53- and ASPP1-dependent apoptosis after gamma-radiation compared to progenitors. p53 inactivation or Bcl-2 overexpression reduced radiation-induced apoptosis and preserved in vivo repopulating HSC function. Despite similar protection from irradiation-induced apoptosis, only Bcl-2-overexpressing HSCs showed higher self-renewal capacity, establishing that intact p53 positively regulates self-renewal independently from apoptosis. The reduced self-renewal of HSCs with inactivated p53 was associated with increased spontaneous gammaH2AX foci in secondary transplants of HSCs. Our data reveal distinct physiological roles of p53 that together ensure optimal HSC function: apoptosis regulation and prevention of gammaH2AX foci accumulation upon HSC self-renewal.", "title": "A distinctive DNA damage response in human hematopoietic stem cells reveals an apoptosis-independent role for p53 in self-renewal." }, { "docid": "20738970", "text": "Epithelial and endothelial tyrosine kinase (Etk), also known as Bmx (bone marrow X kinase) plays an important role in apoptosis of epithelial cells. The goal of this study was to investigate whether Etk is involved in apoptosis of small cell lung cancer (SCLC) cells and correlated with the expression levels of apoptosis-associated proteins such as Bcl-2, Bcl-X(L) and p53. One hundred and seventy-one cases of lung cancer specimens including seventy-one SCLCs and one hundred NSCLCs were immunostained for Etk, Bcl-2, Bcl-X(L) and p53. Parental SCLC H446 cell line, and its subline (H446-Etk) that overexpresses Etk, were used to study the role of Etk in apoptosis induced by doxorubicin. It was found that high expression of Etk occurs in 74.6% of SCLC cases, but only in 40% of NSCLC cases, and there is marked difference in the expression levels of Bcl-2, Bcl-X(L) and p53 between Etk-positive and Etk-negative SCLC cases. Furthermore, the levels of Bcl-2 and Bcl-X(L) significantly increased in H446-Etk cells than that in H446 cells after doxorubicin treatment, and were positively associated with Etk expression. However, p53 did not correspond with Etk expression although its expression decreased greatly with apoptosis both in H446-Etk and H446 cells. After doxorubicin treatment, the cell viability was significantly higher in H446-Etk cells than in parental H446 cells. Downregulation of Etk by Etk siRNA sensitized H446 cells to doxorubicin. Our results indicate that upregulation of tyrosine kinase Etk may be a new mechanism involved in protection of SCLC cells from apoptosis. Bcl-2 and Bcl-X(L) but not p53 may contribute to doxorubicin-induced apoptosis through Etk pathway.", "title": "Non-receptor tyrosine kinase Etk is involved in the apoptosis of small cell lung cancer cells." }, { "docid": "10218447", "text": "Isorhamnetin is one member of flavonoid components which has been used in the treatment of heart disease. Recently the in vitro anti-cancer effect of isorhamnetin on human esophageal squamous carcinoma cell line Eca-109 was investigated in our lab. When Eca-109 cells were in vitro exposed to the graded doses of isorhamnetin (0-80 microg/ml) for 48 h, respectively, isorhamnetin exhibited cytostatic effect on the treated cells, with an IC(50) of 40+/-0.08 microg/ml as estimated by MTT assay. Inhibition on proliferation by isorhamnetin was detected by trypan blue exclusion assay, clone formation test, immunocytochemical assay of PCNA and (3)H-thymidine uptake analysis. Cell cycle distribution was measured by FCM. It was found that the viability of Eca-109 cells was significantly hampered by isorhamnetin. Compared with the negative control group, the treated group which was exposed to isorhamnetin had increased population in G(0)/G(1) phase from 74.6 to 84 while had a significant reduction in G(2)/M phase from 11.9 to 5.8. In addition to its cytostatic effect, isorhamnetin also showed stimulatory effect on apoptosis. Typical apoptotic morphology such as condensation and fragmentation of nuclei and blebbing membrane of the apoptotic cells could be observed through transmission electron microscope. Moreover, the sharp increase in apoptosis rate between the control and treated group were detected by FCM from 6.3 to 16.3. To explore the possible molecular mechanisms that underlie the growth inhibition and apoptosis stimulatory effects of isorhamnetin, the expressions of six proliferation- and death-related genes were detected by FCM. Expressions of bcl-2, c-myc and H-ras were downregulated whereas Bax, c-fos and p53 were upregulated. However, the in vivo experiments were required to further confirm the anti-cancer effects of isorhamnetin. In conclusion, isorhamnetin appears to be a potent drug against esophageal cancer due to its in vitro potential to not only inhibit proliferation but also induce apoptosis of Eca-109 cells.", "title": "The flavonoid component isorhamnetin in vitro inhibits proliferation and induces apoptosis in Eca-109 cells." }, { "docid": "15248287", "text": "Neutrophil apoptosis is a highly regulated process essential for inflammation resolution, the molecular mechanisms of which are only partially elucidated. In this study, we describe a survival pathway controlled by proliferating cell nuclear antigen (PCNA), a nuclear factor involved in DNA replication and repairing of proliferating cells. We show that mature neutrophils, despite their inability to proliferate, express high levels of PCNA exclusively in their cytosol and constitutively associated with procaspases, presumably to prevent their activation. Notably, cytosolic PCNA abundance decreased during apoptosis, and increased during in vitro and in vivo exposure to the survival factor granulocyte colony-stimulating factor (G-CSF). Peptides derived from the cyclin-dependent kinase inhibitor p21, which compete with procaspases to bind PCNA, triggered neutrophil apoptosis thus demonstrating that specific modification of PCNA protein interactions affects neutrophil survival. Furthermore, PCNA overexpression rendered neutrophil-differentiated PLB985 myeloid cells significantly more resistant to TNF-related apoptosis-inducing ligand- or gliotoxin-induced apoptosis. Conversely, a decrease in PCNA expression after PCNA small interfering RNA transfection sensitized these cells to apoptosis. Finally, a mutation in the PCNA interdomain-connecting loop, the binding site for many partners, significantly decreased the PCNA-mediated antiapoptotic effect. These results identify PCNA as a regulator of neutrophil lifespan, thereby highlighting a novel target to potentially modulate pathological inflammation.", "title": "Proliferating cell nuclear antigen acts as a cytoplasmic platform controlling human neutrophil survival" }, { "docid": "6121555", "text": "The aim of this study was to investigate the mechanism through which Sphingosine kinase-1 (SPHK1) exerts its anti-apoptosis activity in glioma cancer cells. We here report that dysregulation of SPHK1 alters the sensitivity of glioma to apoptosis both in vitro and in vivo. Further mechanistic study examined the expression of Bcl-2 family members, including Bcl-2, Mcl-1, Bax and Bim, in SPHK1-overexpressing glioma cells and revealed that only pro-apoptotic Bim was downregulated by SPHK1. Moreover, the transcriptional level of Bim was also altered by SPHK1 in glioma cells. We next confirmed the correlation between SPHK1 and Bim expression in primary glioma specimens. Importantly, increasing SPHK1 expression in glioma cells markedly elevated Akt activity and phosphorylated inactivation of FOXO3a, which led to downregulation of Bim. A pharmacological approach showed that these effects of SPHK1 were dependent on phosphatidylinositol 3-kinase (PI3K). Furthermore, effects of SPHK1 on Akt/FOXO3a/Bim pathway could be reversed by SPHK1 specific RNA interference or SPHK1 inhibitor. Collectively, our results indicate that regulation of the Akt/FOXO3a/Bim pathway may be a novel mechanism by which SPHK1 protects glioma cells from apoptosis, thereby involved in glioma tumorigenesis.", "title": "Sphingosine Kinase 1 Regulates the Akt/FOXO3a/Bim Pathway and Contributes to Apoptosis Resistance in Glioma Cells" }, { "docid": "17231273", "text": "Energy deficiency and dysfunction of the Na+, K+-ATPase are common consequences of many pathological insults. The nature and mechanism of cell injury induced by impaired Na+, K+-ATPase, however, are not well defined. We used cultured cortical neurons to examine the hypothesis that blocking the Na+, K+-ATPase induces apoptosis by depleting cellular K+ and, concurrently, induces necrotic injury in the same cells by increasing intracellular Ca2+ and Na+. The Na+, K+-ATPase inhibitor ouabain induced concentration-dependent neuronal death. Ouabain triggered transient neuronal cell swelling followed by cell shrinkage, accompanied by intracellular Ca2+ and Na+ increase, K+ decrease, cytochrome c release, caspase-3 activation, and DNA laddering. Electron microscopy revealed the coexistence of ultrastructural features of both apoptosis and necrosis in individual cells. The caspase inhibitor Z-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD-FMK) blocked >50% of ouabain-induced neuronal death. Potassium channel blockers or high K+ medium, but not Ca2+ channel blockade, prevented cytochrome c release, caspase activation, and DNA damage. Blocking of K+, Ca2+, or Na+ channels or high K+ medium each attenuated the ouabain-induced cell death; combined inhibition of K+ channels and Ca2+ or Na+ channels resulted in additional protection. Moreover, coapplication of Z-VAD-FMK and nifedipine produced virtually complete neuroprotection. These results suggest that the neuronal death associated with Na+, K+-pump failure consists of concurrent apoptotic and necrotic components, mediated by intracellular depletion of K+ and accumulation of Ca2+ and Na+, respectively. The ouabain-induced hybrid death may represent a distinct form of cell death related to the brain injury of inadequate energy supply and disrupted ion homeostasis.", "title": "Ionic mechanism of ouabain-induced concurrent apoptosis and necrosis in individual cultured cortical neurons" }, { "docid": "38023457", "text": "Severe quantitative and qualitative brown adipocyte defects are common in obesity. To investigate whether aberrant expression of tumor necrosis factor alpha (TNF-alpha) in obesity is involved in functional brown fat atrophy, we have studied genetically obese (ob/ob) mice with targeted null mutations in the genes encoding the two TNF receptors. The absence of both TNF receptors or p55 receptor alone resulted in a significant reduction in brown adipocyte apoptosis and an increase in beta(3)-adrenoreceptor and uncoupling protein-1 expression in obese mice. Increased numbers of multilocular functionally active brown adipocytes, and improved thermoregulation was also observed in obese animals lacking TNF-alpha function. These results indicate that TNF-alpha plays an important role in multiple aspects of brown adipose tissue biology and mediates the abnormalities that occur at this site in obesity.", "title": "Tumor necrosis factor alpha mediates apoptosis of brown adipocytes and defective brown adipocyte function in obesity." }, { "docid": "10576136", "text": "BACKGROUND ST2 is an interleukin (IL)-1 receptor family member with membrane-bound (ST2L) and soluble (sST2) isoforms, and sST2 is a biomarker for poor outcome in patients with myocardial infarction (MI). IL-33, the recently discovered ligand for ST2, activates nuclear factor kappaB and thus may regulate apoptotic cell death. We tested the hypothesis that IL-33 is cardioprotective after MI through ST2 signaling. \n METHODS AND RESULTS IL-33 protected cultured cardiomyocytes from hypoxia-induced apoptosis, and this cardioprotection was partially inhibited by sST2. IL-33 induced expression of the antiapoptotic factors XIAP, cIAP1, and survivin. To define the cardioprotective role of IL-33 in vivo, we performed a blinded and randomized study of ischemia/reperfusion in rats. IL-33 reduced cardiomyocyte apoptosis, suppressed caspase-3 activity, and increased expression of IAP family member proteins. IL-33 decreased both infarct and fibrosis volumes at 15 days; furthermore, both echocardiographic and hemodynamic studies revealed that IL-33 improved ventricular function. To determine whether cardioprotection by IL-33 is mediated through ST2 signaling, a randomized and blinded study of ST2(-/-) versus wild-type littermate mice was performed in 98 mice subjected to MI. At 4 weeks after MI, IL-33 reduced ventricular dilation and improved contractile function in wild-type mice but not in ST2(-/-) mice. Finally, IL-33 improved survival after MI in wild-type but not in ST2(-/-) mice. \n CONCLUSIONS IL-33 prevents cardiomyocyte apoptosis and improves cardiac function and survival after MI through ST2 signaling.", "title": "Interleukin-33 prevents apoptosis and improves survival after experimental myocardial infarction through ST2 signaling." }, { "docid": "21307488", "text": "HER-2/neu amplification or overexpression can make cancer cells resistant to apoptosis and promotes their growth. p53 is crucial in regulating cell growth and apoptosis, and is often mutated or deleted in many types of tumour. Moreover, many tumours with a wild-type gene for p53 do not have normal p53 function, suggesting that some oncogenic signals suppress the function of p53. In this study, we show that HER-2/neu-mediated resistance to DNA-damaging agents requires the activation of Akt, which enhances MDM2-mediated ubiquitination and degradation of p53. Akt physically associates with MDM2 and phosphorylates it at Ser166 and Ser186. Phosphorylation of MDM2 enhances its nuclear localization and its interaction with p300, and inhibits its interaction with p19ARF, thus increasing p53 degradation. Our study indicates that blocking the Akt pathway mediated by HER-2/neu would increase the cytotoxic effect of DNA-damaging drugs in tumour cells with wild-type p53.", "title": "HER-2/neu induces p53 ubiquitination via Akt-mediated MDM2 phosphorylation" }, { "docid": "9197092", "text": "Dietary polyphenols have been associated with reduced risk of chronic diseases, but the precise molecular mechanisms of protection remain unclear. This work was aimed at studying the effect of (-)-epicatechin (EC) and chlorogenic acid (CGA) on the regulation of apoptotic and survival/proliferation pathways in a human hepatoma cell line (HepG2). EC or CGA treatment for 18 h had a slight effect on cell viability and decreased reactive oxygen species formation, and EC alone promoted cell proliferation, whereas CGA increased glutathione levels. Phenols neither induced the caspase cascade for apoptosis nor affected expression levels of Bcl-xL or Bax. A sustained activation of the major survival signals AKT/PI-3-kinase and ERK was shown in EC-treated cells, rather than in CGA-exposed cells. These data suggest that EC and CGA have no effect on apoptosis and enhance the intrinsic cellular tolerance against oxidative insults either by activating survival/proliferation pathways or by increasing antioxidant potential in HepG2.", "title": "Molecular mechanisms of (-)-epicatechin and chlorogenic acid on the regulation of the apoptotic and survival/proliferation pathways in a human hepatoma cell line." } ]

[ { "docid": "6173523", "text": "IMPORTANCE Identification of the bacterium responsible for an outbreak can aid in disease management. However, traditional culture-based diagnosis can be difficult, particularly if no specific diagnostic test is available for an outbreak strain. \n OBJECTIVE To explore the potential of metagenomics, which is the direct sequencing of DNA extracted from microbiologically complex samples, as an open-ended clinical discovery platform capable of identifying and characterizing bacterial strains from an outbreak without laboratory culture. \n DESIGN, SETTING, AND PATIENTS In a retrospective investigation, 45 samples were selected from fecal specimens obtained from patients with diarrhea during the 2011 outbreak of Shiga-toxigenic Escherichia coli (STEC) O104:H4 in Germany. Samples were subjected to high-throughput sequencing (August-September 2012), followed by a 3-phase analysis (November 2012-February 2013). In phase 1, a de novo assembly approach was developed to obtain a draft genome of the outbreak strain. In phase 2, the depth of coverage of the outbreak strain genome was determined in each sample. In phase 3, sequences from each sample were compared with sequences from known bacteria to identify pathogens other than the outbreak strain. \n MAIN OUTCOMES AND MEASURES The recovery of genome sequence data for the purposes of identification and characterization of the outbreak strain and other pathogens from fecal samples. \n RESULTS During phase 1, a draft genome of the STEC outbreak strain was obtained. During phase 2, the outbreak strain genome was recovered from 10 samples at greater than 10-fold coverage and from 26 samples at greater than 1-fold coverage. Sequences from the Shiga-toxin genes were detected in 27 of 40 STEC-positive samples (67%). In phase 3, sequences from Clostridium difficile, Campylobacter jejuni, Campylobacter concisus, and Salmonella enterica were recovered. \n CONCLUSIONS AND RELEVANCE These results suggest the potential of metagenomics as a culture-independent approach for the identification of bacterial pathogens during an outbreak of diarrheal disease. Challenges include improving diagnostic sensitivity, speeding up and simplifying workflows, and reducing costs.", "title": "A culture-independent sequence-based metagenomics approach to the investigation of an outbreak of Shiga-toxigenic Escherichia coli O104:H4." } ]

[ { "docid": "14464451", "text": "Next-generation-sequencing (NGS) has revolutionized the field of genome assembly because of its much higher data throughput and much lower cost compared with traditional Sanger sequencing. However, NGS poses new computational challenges to de novo genome assembly. Among the challenges, GC bias in NGS data is known to aggravate genome assembly. However, it is not clear to what extent GC bias affects genome assembly in general. In this work, we conduct a systematic analysis on the effects of GC bias on genome assembly. Our analyses reveal that GC bias only lowers assembly completeness when the degree of GC bias is above a threshold. At a strong GC bias, the assembly fragmentation due to GC bias can be explained by the low coverage of reads in the GC-poor or GC-rich regions of a genome. This effect is observed for all the assemblers under study. Increasing the total amount of NGS data thus rescues the assembly fragmentation because of GC bias. However, the amount of data needed for a full rescue depends on the distribution of GC contents. Both low and high coverage depths due to GC bias lower the accuracy of assembly. These pieces of information provide guidance toward a better de novo genome assembly in the presence of GC bias.", "title": "Effects of GC Bias in Next-Generation-Sequencing Data on De Novo Genome Assembly" }, { "docid": "14185503", "text": "BACKGROUND Genlisea aurea (Lentibulariaceae) is a carnivorous plant with unusually small genome size - 63.6 Mb - one of the smallest known among higher plants. Data on the genome sizes and the phylogeny of Genlisea suggest that this is a derived state within the genus. Thus, G. aurea is an excellent model organism for studying evolutionary mechanisms of genome contraction. \n RESULTS Here we report sequencing and de novo draft assembly of G. aurea genome. The assembly consists of 10,687 contigs of the total length of 43.4 Mb and includes 17,755 complete and partial protein-coding genes. Its comparison with the genome of Mimulus guttatus, another representative of higher core Lamiales clade, reveals striking differences in gene content and length of non-coding regions. \n CONCLUSIONS Genome contraction was a complex process, which involved gene loss and reduction of lengths of introns and intergenic regions, but not intron loss. The gene loss is more frequent for the genes that belong to multigenic families indicating that genetic redundancy is an important prerequisite for genome size reduction.", "title": "The miniature genome of a carnivorous plant Genlisea aurea contains a low number of genes and short non-coding sequences" }, { "docid": "13123189", "text": "BACKGROUND RNA-Seq is revolutionizing the way transcript abundances are measured. A key challenge in transcript quantification from RNA-Seq data is the handling of reads that map to multiple genes or isoforms. This issue is particularly important for quantification with de novo transcriptome assemblies in the absence of sequenced genomes, as it is difficult to determine which transcripts are isoforms of the same gene. A second significant issue is the design of RNA-Seq experiments, in terms of the number of reads, read length, and whether reads come from one or both ends of cDNA fragments. \n RESULTS We present RSEM, an user-friendly software package for quantifying gene and isoform abundances from single-end or paired-end RNA-Seq data. RSEM outputs abundance estimates, 95% credibility intervals, and visualization files and can also simulate RNA-Seq data. In contrast to other existing tools, the software does not require a reference genome. Thus, in combination with a de novo transcriptome assembler, RSEM enables accurate transcript quantification for species without sequenced genomes. On simulated and real data sets, RSEM has superior or comparable performance to quantification methods that rely on a reference genome. Taking advantage of RSEM's ability to effectively use ambiguously-mapping reads, we show that accurate gene-level abundance estimates are best obtained with large numbers of short single-end reads. On the other hand, estimates of the relative frequencies of isoforms within single genes may be improved through the use of paired-end reads, depending on the number of possible splice forms for each gene. \n CONCLUSIONS RSEM is an accurate and user-friendly software tool for quantifying transcript abundances from RNA-Seq data. As it does not rely on the existence of a reference genome, it is particularly useful for quantification with de novo transcriptome assemblies. In addition, RSEM has enabled valuable guidance for cost-efficient design of quantification experiments with RNA-Seq, which is currently relatively expensive.", "title": "RSEM: accurate transcript quantification from RNA-Seq data with or without a reference genome" }, { "docid": "25041967", "text": "Human artificial chromosomes have been used to model requirements for human chromosome segregation and to explore the nature of sequences competent for centromere function. Normal human centromeres require specialized chromatin that consists of alpha satellite DNA complexed with epigenetically modified histones and centromere-specific proteins. While several types of alpha satellite DNA have been used to assemble de novo centromeres in artificial chromosome assays, the extent to which they fully recapitulate normal centromere function has not been explored. Here, we have used two kinds of alpha satellite DNA, DXZ1 (from the X chromosome) and D17Z1 (from chromosome 17), to generate human artificial chromosomes. Although artificial chromosomes are mitotically stable over many months in culture, when we examined their segregation in individual cell divisions using an anaphase assay, artificial chromosomes exhibited more segregation errors than natural human chromosomes (P < 0.001). Naturally occurring, but abnormal small ring chromosomes derived from chromosome 17 and the X chromosome also missegregate more than normal chromosomes, implicating overall chromosome size and/or structure in the fidelity of chromosome segregation. As different artificial chromosomes missegregate over a fivefold range, the data suggest that variable centromeric DNA content and/or epigenetic assembly can influence the mitotic behavior of artificial chromosomes.", "title": "Human artificial chromosomes with alpha satellite-based de novo centromeres show increased frequency of nondisjunction and anaphase lag." }, { "docid": "32770503", "text": "Massively parallel sequencing of cDNA has enabled deep and efficient probing of transcriptomes. Current approaches for transcript reconstruction from such data often rely on aligning reads to a reference genome, and are thus unsuitable for samples with a partial or missing reference genome. Here we present the Trinity method for de novo assembly of full-length transcripts and evaluate it on samples from fission yeast, mouse and whitefly, whose reference genome is not yet available. By efficiently constructing and analyzing sets of de Bruijn graphs, Trinity fully reconstructs a large fraction of transcripts, including alternatively spliced isoforms and transcripts from recently duplicated genes. Compared with other de novo transcriptome assemblers, Trinity recovers more full-length transcripts across a broad range of expression levels, with a sensitivity similar to methods that rely on genome alignments. Our approach provides a unified solution for transcriptome reconstruction in any sample, especially in the absence of a reference genome.", "title": "Full-length transcriptome assembly from RNA-Seq data without a reference genome." }, { "docid": "15478227", "text": "The wild species of the genus Oryza contain a largely untapped reservoir of agronomically important genes for rice improvement. Here we report the 261-Mb de novo assembled genome sequence of Oryza brachyantha. Low activity of long-terminal repeat retrotransposons and massive internal deletions of ancient long-terminal repeat elements lead to the compact genome of Oryza brachyantha. We model 32,038 protein-coding genes in the Oryza brachyantha genome, of which only 70% are located in collinear positions in comparison with the rice genome. Analysing breakpoints of non-collinear genes suggests that double-strand break repair through non-homologous end joining has an important role in gene movement and erosion of collinearity in the Oryza genomes. Transition of euchromatin to heterochromatin in the rice genome is accompanied by segmental and tandem duplications, further expanded by transposable element insertions. The high-quality reference genome sequence of Oryza brachyantha provides an important resource for functional and evolutionary studies in the genus Oryza.", "title": "Whole-genome sequencing of Oryza brachyantha reveals mechanisms underlying Oryza genome evolution" }, { "docid": "17447653", "text": "BACKGROUND Sequence similarity searching is a very important bioinformatics task. While Basic Local Alignment Search Tool (BLAST) outperforms exact methods through its use of heuristics, the speed of the current BLAST software is suboptimal for very long queries or database sequences. There are also some shortcomings in the user-interface of the current command-line applications. \n RESULTS We describe features and improvements of rewritten BLAST software and introduce new command-line applications. Long query sequences are broken into chunks for processing, in some cases leading to dramatically shorter run times. For long database sequences, it is possible to retrieve only the relevant parts of the sequence, reducing CPU time and memory usage for searches of short queries against databases of contigs or chromosomes. The program can now retrieve masking information for database sequences from the BLAST databases. A new modular software library can now access subject sequence data from arbitrary data sources. We introduce several new features, including strategy files that allow a user to save and reuse their favorite set of options. The strategy files can be uploaded to and downloaded from the NCBI BLAST web site. \n CONCLUSION The new BLAST command-line applications, compared to the current BLAST tools, demonstrate substantial speed improvements for long queries as well as chromosome length database sequences. We have also improved the user interface of the command-line applications.", "title": "BLAST+: architecture and applications" }, { "docid": "15960670", "text": "The centromere is a chromatin region that serves as the spindle attachment point and directs accurate inheritance of eukaryotic chromosomes during cell divisions. However, the mechanism by which the centromere assembles and stabilizes at a specific genomic region is not clear. The de novo formation of a human/mammalian artificial chromosome (HAC/MAC) with a functional centromere assembly requires the presence of alpha-satellite DNA containing binding motifs for the centromeric CENP-B protein. We demonstrate here that de novo centromere assembly on HAC/MAC is dependent on CENP-B. In contrast, centromere formation is suppressed in cells expressing CENP-B when alpha-satellite DNA was integrated into a chromosomal site. Remarkably, on those integration sites CENP-B enhances histone H3-K9 trimethylation and DNA methylation, thereby stimulating heterochromatin formation. Thus, we propose that CENP-B plays a dual role in centromere formation, ensuring de novo formation on DNA lacking a functional centromere but preventing the formation of excess centromeres on chromosomes.", "title": "CENP-B Controls Centromere Formation Depending on the Chromatin Context" }, { "docid": "16626846", "text": "Crude oils can be major contaminants of the marine ecosystem and microorganisms play a significant role in the degradation of its main constituents. To increase our understanding of the microbial hydrocarbon degradation process in the marine ecosystem, we collected crude oil from an active seep area located in the Santa Barbara Channel (SBC) and generated a total of about 52 Gb of raw metagenomic sequence data. The assembled data comprised ~500 Mb, representing ~1.1 million genes derived primarily from chemolithoautotrophic bacteria. Members of Oceanospirillales, a bacterial order belonging to the Deltaproteobacteria, recruited less than 2% of the assembled genes within the SBC metagenome. In contrast, the microbial community associated with the oil plume that developed in the aftermath of the Deepwater Horizon (DWH) blowout in 2010, was dominated by Oceanospirillales, which comprised more than 60% of the metagenomic data generated from the DWH oil plume. This suggests that Oceanospirillales might play a less significant role in the microbially mediated hydrocarbon conversion within the SBC seep oil compared to the DWH plume oil. We hypothesize that this difference results from the SBC oil seep being mostly anaerobic, while the DWH oil plume is aerobic. Within the Archaea, the phylum Euryarchaeota, recruited more than 95% of the assembled archaeal sequences from the SBC oil seep metagenome, with more than 50% of the sequences assigned to members of the orders Methanomicrobiales and Methanosarcinales. These orders contain organisms capable of anaerobic methanogenesis and methane oxidation (AOM) and we hypothesize that these orders - and their metabolic capabilities - may be fundamental to the ecology of the SBC oil seep.", "title": "Metagenomic analysis of microbial consortium from natural crude oil that seeps into the marine ecosystem offshore Southern California" }, { "docid": "2576811", "text": "Epithelial integrity is vitally important, and its deregulation causes early stage cancer. De novo formation of an adherens junction (AJ) between single epithelial cells requires coordinated, spatial actin dynamics, but the mechanisms steering nascent actin polymerization for cell-cell adhesion initiation are not well understood. Here we investigated real-time actin assembly during daughter cell-cell adhesion formation in human breast epithelial cells in 3D environments. We identify formin-like 2 (FMNL2) as being specifically required for actin assembly and turnover at newly formed cell-cell contacts as well as for human epithelial lumen formation. FMNL2 associates with components of the AJ complex involving Rac1 activity and the FMNL2 C terminus. Optogenetic control of Rac1 in living cells rapidly drove FMNL2 to epithelial cell-cell contact zones. Furthermore, Rac1-induced actin assembly and subsequent AJ formation critically depends on FMNL2. These data uncover FMNL2 as a driver for human epithelial AJ formation downstream of Rac1.", "title": "Junctional actin assembly is mediated by Formin-like 2 downstream of Rac1" }, { "docid": "11244195", "text": "MOTIVATION Accurate alignment of high-throughput RNA-seq data is a challenging and yet unsolved problem because of the non-contiguous transcript structure, relatively short read lengths and constantly increasing throughput of the sequencing technologies. Currently available RNA-seq aligners suffer from high mapping error rates, low mapping speed, read length limitation and mapping biases. \n RESULTS To align our large (>80 billon reads) ENCODE Transcriptome RNA-seq dataset, we developed the Spliced Transcripts Alignment to a Reference (STAR) software based on a previously undescribed RNA-seq alignment algorithm that uses sequential maximum mappable seed search in uncompressed suffix arrays followed by seed clustering and stitching procedure. STAR outperforms other aligners by a factor of >50 in mapping speed, aligning to the human genome 550 million 2 × 76 bp paired-end reads per hour on a modest 12-core server, while at the same time improving alignment sensitivity and precision. In addition to unbiased de novo detection of canonical junctions, STAR can discover non-canonical splices and chimeric (fusion) transcripts, and is also capable of mapping full-length RNA sequences. Using Roche 454 sequencing of reverse transcription polymerase chain reaction amplicons, we experimentally validated 1960 novel intergenic splice junctions with an 80-90% success rate, corroborating the high precision of the STAR mapping strategy. AVAILABILITY AND IMPLEMENTATION STAR is implemented as a standalone C++ code. STAR is free open source software distributed under GPLv3 license and can be downloaded from http://code.google.com/p/rna-star/.", "title": "STAR: ultrafast universal RNA-seq aligner." }, { "docid": "14275671", "text": "The similarity in the three-dimensional structures of homologous proteins imposes strong constraints on their sequence variability. It has long been suggested that the resulting correlations among amino acid compositions at different sequence positions can be exploited to infer spatial contacts within the tertiary protein structure. Crucial to this inference is the ability to disentangle direct and indirect correlations, as accomplished by the recently introduced Direct Coupling Analysis (DCA) (Weigt et al. (2009) Proc Natl Acad Sci 106:67). Here we develop a computationally efficient implementation of DCA, which allows us to evaluate the accuracy of contact prediction by DCA for a large number of protein domains, based purely on sequence information. DCA is shown to yield a large number of correctly predicted contacts, recapitulating the global structure of the contact map for the majority of the protein domains examined. Furthermore, our analysis captures clear signals beyond intra- domain residue contacts, arising, e.g., from alternative protein conformations, ligand- mediated residue couplings, and inter-domain interactions in protein oligomers. Our findings suggest that contacts predicted by DCA can be used as a reliable guide to facilitate computational predictions of alternative protein conformations, protein complex formation, and even the de novo prediction of protein domain structures, provided the existence of a large number of homologous sequences which are being rapidly made available due to advances in genome sequencing.", "title": "Direct-coupling analysis of residue co-evolution captures native contacts across many protein families" }, { "docid": "19138874", "text": "The biogenesis of the many functional compartments contained in the mammalian cell nucleus is poorly understood. More specifically, little is known regarding the initial nucleation step required for nuclear body formation. Here we show that RNA can function as a structural element and a nucleator of nuclear bodies. We find that several types of coding and noncoding RNAs are sufficient to de novo assemble, and are physiologically enriched in, histone locus bodies (with associated Cajal bodies), nuclear speckles, paraspeckles and nuclear stress bodies. Formation of nuclear bodies occurs through recruitment and accumulation of proteins resident in the nuclear bodies by nucleating RNA. These results demonstrate that transcription is a driving force in nuclear body formation and RNA transcripts can function as a scaffold in the formation of major nuclear bodies. Together, these data suggest that RNA-primed biogenesis of nuclear bodies is a general principle of nuclear organization.", "title": "Nucleation of nuclear bodies by RNA" }, { "docid": "28069701", "text": "Detecting and localizing selective sweeps on the basis of SNP data has recently received considerable attention. Here we introduce the use of hidden Markov models (HMMs) for the detection of selective sweeps in DNA sequences. Like previously published methods, our HMMs use the site frequency spectrum, and the spatial pattern of diversity along the sequence, to identify selection. In contrast to earlier approaches, our HMMs explicitly model the correlation structure between linked sites. The detection power of our methods, and their accuracy for estimating the selected site location, is similar to that of competing methods for constant size populations. In the case of population bottlenecks, however, our methods frequently showed fewer false positives.", "title": "Detecting selective sweeps: a new approach based on hidden markov models." }, { "docid": "152245", "text": "The genomic RNA of an alphavirus encodes four different nonstructural proteins, nsP1, nsP2, nsP3, and nsP4. The polyprotein P123 is produced when translation terminates at an opal termination codon between nsP3 and nsP4. The polyprotein P1234 is produced when translational readthrough occurs or when the opal termination codon has been replaced by a sense codon in the alphavirus genome. Evolutionary pressures appear to have maintained genomic sequences encoding both a stop codon (opal) and an open reading frame (arginine) as a general feature of the O'nyong-nyong virus (ONNV) genome, indicating that both are required at some point. Alternate replication of ONNVs in both vertebrate and invertebrate hosts may determine predominance of a particular codon at this locus in the viral quasispecies. However, no systematic study has previously tested this hypothesis in whole animals. We report here the results of the first study to investigate in a natural mosquito host the functional significance of the opal stop codon in an alphavirus genome. We used a full-length cDNA clone of ONNV to construct a series of mutants in which the arginine between nsP3 and nsP4 was replaced with an opal, ochre, or amber stop codon. The presence of an opal stop codon upstream of nsP4 nearly doubled (75.5%) the infectivity of ONNV over that of virus possessing a codon for the amino acid arginine at the corresponding position (39.8%). Although the frequency with which the opal virus disseminated from the mosquito midgut did not differ significantly from that of the arginine virus on days 8 and 10, dissemination did began earlier in mosquitoes infected with the opal virus. Although a clear fitness advantage is provided to ONNV by the presence of an opal codon between nsP3 and nsP4 in Anopheles gambiae, sequence analysis of ONNV RNA extracted from mosquito bodies and heads indicated codon usage at this position corresponded with that of the virus administered in the blood meal. These results suggest that while selection of ONNV variants is occurring, de novo mutation at the position between nsP3 and nsP4 does not readily occur in the mosquito. Taken together, these results suggest that the primary fitness advantage provided to ONNV by the presence of an opal codon between nsP3 and nsP4 is related to mosquito infectivity.", "title": "Effects of an opal termination codon preceding the nsP4 gene sequence in the O'Nyong-Nyong virus genome on Anopheles gambiae infectivity." }, { "docid": "31634628", "text": "Cell-free tumor DNA (ctDNA) has the potential to enable non-invasive diagnostic tests for personalized medicine in providing similar molecular information as that derived from invasive tumor biopsies. The histology-independent phase II SHIVA trial matches patients with targeted therapeutics based on previous screening of multiple somatic mutations using metastatic biopsies. To evaluate the utility of ctDNA in this trial, as an ancillary study we performed de novo detection of somatic mutations using plasma DNA compared to metastasis biopsies in 34 patients covering 18 different tumor types, scanning 46 genes and more than 6800 COSMIC mutations with a multiplexed next-generation sequencing panel. In 27 patients, 28 of 29 mutations identified in metastasis biopsies (97%) were detected in matched ctDNA. Among these 27 patients, one additional mutation was found in ctDNA only. In the seven other patients, mutation detection from metastasis biopsy failed due to inadequate biopsy material, but was successful in all plasma DNA samples providing three more potential actionable mutations. These results suggest that ctDNA analysis is a potential alternative and/or replacement to analyses using costly, harmful and lengthy tissue biopsies of metastasis, irrespective of cancer type and metastatic site, for multiplexed mutation detection in selecting personalized therapies based on the patient's tumor genetic content.", "title": "Circulating tumor DNA as a non-invasive substitute to metastasis biopsy for tumor genotyping and personalized medicine in a prospective trial across all tumor types." }, { "docid": "21387297", "text": "Cardiovascular disease is a leading cause of death worldwide. The limited capability of heart tissue to regenerate has prompted methodological developments for creating de novo cardiomyocytes, both in vitro and in vivo. Beyond uses in cell replacement therapy, patient-specific cardiomyocytes may find applications in drug testing, drug discovery, and disease modeling. Recently, approaches for generating cardiomyocytes have expanded to encompass three major sources of starting cells: human pluripotent stem cells (hPSCs), adult heart-derived cardiac progenitor cells (CPCs), and reprogrammed fibroblasts. We discuss state-of-the-art methods for generating de novo cardiomyocytes from hPSCs and reprogrammed fibroblasts, highlighting potential applications and future challenges.", "title": "Production of de novo cardiomyocytes: human pluripotent stem cell differentiation and direct reprogramming." }, { "docid": "22186938", "text": "Human artificial chromosomes (HACs) are autonomous molecules that can function and segregate as normal chromosomes in human cells. De novo HACs have successfully been used as gene expression vectors to complement genetic deficiencies in human cultured cells. HACs now offer the possibility of studying the regulation and expression of large genes in a variety of cell types from different tissues and correcting gene deficiencies caused by human inherited diseases. Complementary gene expression studies in mice, especially in mouse models of human genetic diseases, are also important in determining if large human transgenes can be expressed appropriately from artificial chromosomes. Toward this aim we are establishing artificial chromosomes in murine cells as novel gene expression vectors. Initially we transferred HAC vectors into murine cells, but were unable to generate de novo HACs at a reasonable frequency. We then transferred HACs previously established in human HT1080 cells to three different murine cell types by microcell fusion, followed by positive selection. We observed that the HACs in murine cells bound centromere protein C (CENP-C), a marker of active centromeres, and were detected under selection but rapidly lost when selection was removed. These results suggest that the HACs maintain at least a partially functional centromere complex in murine cells, but other factors are required for stability and segregation. Artificial chromosomes containing mouse centromeric sequences may be required for better stability and maintenance in murine cells.", "title": "Human artificial chromosomes containing chromosome 17 alphoid DNA maintain an active centromere in murine cells but are not stable." }, { "docid": "18361917", "text": "PURPOSE The adult newt can regenerate lens from pigmented epithelial cells (PECs) of the dorsal iris via dedifferentiation. The purpose of this research is to obtain sequence resources for a newt lens regeneration study and to obtain insights of dedifferentiation at the molecular level. \n METHODS mRNA was purified from iris during dedifferentiation and its cDNA library was constructed. From the cDNA library 10,449 clones were sequenced and analyzed. \n RESULTS From 10,449 reads, 780 contigs and 1,666 singlets were annotated. The presence of several cancer- and apoptosis-related genes during newt dedifferentiation was revealed. Moreover, several candidate genes, which might participate in reprogramming during dedifferentiation, were also found. \n CONCLUSIONS The expression of cancer- and apoptosis-related genes could be hallmarks during dedifferentiation. The expression sequence tag (EST) resource is useful for the future study of newt dedifferentiation, and the sequence information is available in GenBank (accession numbers; FS290155-FS300559).", "title": "Expression profiles during dedifferentiation in newt lens regeneration revealed by expressed sequence tags" } ]

[ { "docid": "6173523", "text": "IMPORTANCE Identification of the bacterium responsible for an outbreak can aid in disease management. However, traditional culture-based diagnosis can be difficult, particularly if no specific diagnostic test is available for an outbreak strain. \n OBJECTIVE To explore the potential of metagenomics, which is the direct sequencing of DNA extracted from microbiologically complex samples, as an open-ended clinical discovery platform capable of identifying and characterizing bacterial strains from an outbreak without laboratory culture. \n DESIGN, SETTING, AND PATIENTS In a retrospective investigation, 45 samples were selected from fecal specimens obtained from patients with diarrhea during the 2011 outbreak of Shiga-toxigenic Escherichia coli (STEC) O104:H4 in Germany. Samples were subjected to high-throughput sequencing (August-September 2012), followed by a 3-phase analysis (November 2012-February 2013). In phase 1, a de novo assembly approach was developed to obtain a draft genome of the outbreak strain. In phase 2, the depth of coverage of the outbreak strain genome was determined in each sample. In phase 3, sequences from each sample were compared with sequences from known bacteria to identify pathogens other than the outbreak strain. \n MAIN OUTCOMES AND MEASURES The recovery of genome sequence data for the purposes of identification and characterization of the outbreak strain and other pathogens from fecal samples. \n RESULTS During phase 1, a draft genome of the STEC outbreak strain was obtained. During phase 2, the outbreak strain genome was recovered from 10 samples at greater than 10-fold coverage and from 26 samples at greater than 1-fold coverage. Sequences from the Shiga-toxin genes were detected in 27 of 40 STEC-positive samples (67%). In phase 3, sequences from Clostridium difficile, Campylobacter jejuni, Campylobacter concisus, and Salmonella enterica were recovered. \n CONCLUSIONS AND RELEVANCE These results suggest the potential of metagenomics as a culture-independent approach for the identification of bacterial pathogens during an outbreak of diarrheal disease. Challenges include improving diagnostic sensitivity, speeding up and simplifying workflows, and reducing costs.", "title": "A culture-independent sequence-based metagenomics approach to the investigation of an outbreak of Shiga-toxigenic Escherichia coli O104:H4." } ]

[ { "docid": "14464451", "text": "Next-generation-sequencing (NGS) has revolutionized the field of genome assembly because of its much higher data throughput and much lower cost compared with traditional Sanger sequencing. However, NGS poses new computational challenges to de novo genome assembly. Among the challenges, GC bias in NGS data is known to aggravate genome assembly. However, it is not clear to what extent GC bias affects genome assembly in general. In this work, we conduct a systematic analysis on the effects of GC bias on genome assembly. Our analyses reveal that GC bias only lowers assembly completeness when the degree of GC bias is above a threshold. At a strong GC bias, the assembly fragmentation due to GC bias can be explained by the low coverage of reads in the GC-poor or GC-rich regions of a genome. This effect is observed for all the assemblers under study. Increasing the total amount of NGS data thus rescues the assembly fragmentation because of GC bias. However, the amount of data needed for a full rescue depends on the distribution of GC contents. Both low and high coverage depths due to GC bias lower the accuracy of assembly. These pieces of information provide guidance toward a better de novo genome assembly in the presence of GC bias.", "title": "Effects of GC Bias in Next-Generation-Sequencing Data on De Novo Genome Assembly" }, { "docid": "14185503", "text": "BACKGROUND Genlisea aurea (Lentibulariaceae) is a carnivorous plant with unusually small genome size - 63.6 Mb - one of the smallest known among higher plants. Data on the genome sizes and the phylogeny of Genlisea suggest that this is a derived state within the genus. Thus, G. aurea is an excellent model organism for studying evolutionary mechanisms of genome contraction. \n RESULTS Here we report sequencing and de novo draft assembly of G. aurea genome. The assembly consists of 10,687 contigs of the total length of 43.4 Mb and includes 17,755 complete and partial protein-coding genes. Its comparison with the genome of Mimulus guttatus, another representative of higher core Lamiales clade, reveals striking differences in gene content and length of non-coding regions. \n CONCLUSIONS Genome contraction was a complex process, which involved gene loss and reduction of lengths of introns and intergenic regions, but not intron loss. The gene loss is more frequent for the genes that belong to multigenic families indicating that genetic redundancy is an important prerequisite for genome size reduction.", "title": "The miniature genome of a carnivorous plant Genlisea aurea contains a low number of genes and short non-coding sequences" }, { "docid": "13123189", "text": "BACKGROUND RNA-Seq is revolutionizing the way transcript abundances are measured. A key challenge in transcript quantification from RNA-Seq data is the handling of reads that map to multiple genes or isoforms. This issue is particularly important for quantification with de novo transcriptome assemblies in the absence of sequenced genomes, as it is difficult to determine which transcripts are isoforms of the same gene. A second significant issue is the design of RNA-Seq experiments, in terms of the number of reads, read length, and whether reads come from one or both ends of cDNA fragments. \n RESULTS We present RSEM, an user-friendly software package for quantifying gene and isoform abundances from single-end or paired-end RNA-Seq data. RSEM outputs abundance estimates, 95% credibility intervals, and visualization files and can also simulate RNA-Seq data. In contrast to other existing tools, the software does not require a reference genome. Thus, in combination with a de novo transcriptome assembler, RSEM enables accurate transcript quantification for species without sequenced genomes. On simulated and real data sets, RSEM has superior or comparable performance to quantification methods that rely on a reference genome. Taking advantage of RSEM's ability to effectively use ambiguously-mapping reads, we show that accurate gene-level abundance estimates are best obtained with large numbers of short single-end reads. On the other hand, estimates of the relative frequencies of isoforms within single genes may be improved through the use of paired-end reads, depending on the number of possible splice forms for each gene. \n CONCLUSIONS RSEM is an accurate and user-friendly software tool for quantifying transcript abundances from RNA-Seq data. As it does not rely on the existence of a reference genome, it is particularly useful for quantification with de novo transcriptome assemblies. In addition, RSEM has enabled valuable guidance for cost-efficient design of quantification experiments with RNA-Seq, which is currently relatively expensive.", "title": "RSEM: accurate transcript quantification from RNA-Seq data with or without a reference genome" }, { "docid": "32770503", "text": "Massively parallel sequencing of cDNA has enabled deep and efficient probing of transcriptomes. Current approaches for transcript reconstruction from such data often rely on aligning reads to a reference genome, and are thus unsuitable for samples with a partial or missing reference genome. Here we present the Trinity method for de novo assembly of full-length transcripts and evaluate it on samples from fission yeast, mouse and whitefly, whose reference genome is not yet available. By efficiently constructing and analyzing sets of de Bruijn graphs, Trinity fully reconstructs a large fraction of transcripts, including alternatively spliced isoforms and transcripts from recently duplicated genes. Compared with other de novo transcriptome assemblers, Trinity recovers more full-length transcripts across a broad range of expression levels, with a sensitivity similar to methods that rely on genome alignments. Our approach provides a unified solution for transcriptome reconstruction in any sample, especially in the absence of a reference genome.", "title": "Full-length transcriptome assembly from RNA-Seq data without a reference genome." }, { "docid": "25041967", "text": "Human artificial chromosomes have been used to model requirements for human chromosome segregation and to explore the nature of sequences competent for centromere function. Normal human centromeres require specialized chromatin that consists of alpha satellite DNA complexed with epigenetically modified histones and centromere-specific proteins. While several types of alpha satellite DNA have been used to assemble de novo centromeres in artificial chromosome assays, the extent to which they fully recapitulate normal centromere function has not been explored. Here, we have used two kinds of alpha satellite DNA, DXZ1 (from the X chromosome) and D17Z1 (from chromosome 17), to generate human artificial chromosomes. Although artificial chromosomes are mitotically stable over many months in culture, when we examined their segregation in individual cell divisions using an anaphase assay, artificial chromosomes exhibited more segregation errors than natural human chromosomes (P < 0.001). Naturally occurring, but abnormal small ring chromosomes derived from chromosome 17 and the X chromosome also missegregate more than normal chromosomes, implicating overall chromosome size and/or structure in the fidelity of chromosome segregation. As different artificial chromosomes missegregate over a fivefold range, the data suggest that variable centromeric DNA content and/or epigenetic assembly can influence the mitotic behavior of artificial chromosomes.", "title": "Human artificial chromosomes with alpha satellite-based de novo centromeres show increased frequency of nondisjunction and anaphase lag." }, { "docid": "17447653", "text": "BACKGROUND Sequence similarity searching is a very important bioinformatics task. While Basic Local Alignment Search Tool (BLAST) outperforms exact methods through its use of heuristics, the speed of the current BLAST software is suboptimal for very long queries or database sequences. There are also some shortcomings in the user-interface of the current command-line applications. \n RESULTS We describe features and improvements of rewritten BLAST software and introduce new command-line applications. Long query sequences are broken into chunks for processing, in some cases leading to dramatically shorter run times. For long database sequences, it is possible to retrieve only the relevant parts of the sequence, reducing CPU time and memory usage for searches of short queries against databases of contigs or chromosomes. The program can now retrieve masking information for database sequences from the BLAST databases. A new modular software library can now access subject sequence data from arbitrary data sources. We introduce several new features, including strategy files that allow a user to save and reuse their favorite set of options. The strategy files can be uploaded to and downloaded from the NCBI BLAST web site. \n CONCLUSION The new BLAST command-line applications, compared to the current BLAST tools, demonstrate substantial speed improvements for long queries as well as chromosome length database sequences. We have also improved the user interface of the command-line applications.", "title": "BLAST+: architecture and applications" }, { "docid": "15478227", "text": "The wild species of the genus Oryza contain a largely untapped reservoir of agronomically important genes for rice improvement. Here we report the 261-Mb de novo assembled genome sequence of Oryza brachyantha. Low activity of long-terminal repeat retrotransposons and massive internal deletions of ancient long-terminal repeat elements lead to the compact genome of Oryza brachyantha. We model 32,038 protein-coding genes in the Oryza brachyantha genome, of which only 70% are located in collinear positions in comparison with the rice genome. Analysing breakpoints of non-collinear genes suggests that double-strand break repair through non-homologous end joining has an important role in gene movement and erosion of collinearity in the Oryza genomes. Transition of euchromatin to heterochromatin in the rice genome is accompanied by segmental and tandem duplications, further expanded by transposable element insertions. The high-quality reference genome sequence of Oryza brachyantha provides an important resource for functional and evolutionary studies in the genus Oryza.", "title": "Whole-genome sequencing of Oryza brachyantha reveals mechanisms underlying Oryza genome evolution" }, { "docid": "16626846", "text": "Crude oils can be major contaminants of the marine ecosystem and microorganisms play a significant role in the degradation of its main constituents. To increase our understanding of the microbial hydrocarbon degradation process in the marine ecosystem, we collected crude oil from an active seep area located in the Santa Barbara Channel (SBC) and generated a total of about 52 Gb of raw metagenomic sequence data. The assembled data comprised ~500 Mb, representing ~1.1 million genes derived primarily from chemolithoautotrophic bacteria. Members of Oceanospirillales, a bacterial order belonging to the Deltaproteobacteria, recruited less than 2% of the assembled genes within the SBC metagenome. In contrast, the microbial community associated with the oil plume that developed in the aftermath of the Deepwater Horizon (DWH) blowout in 2010, was dominated by Oceanospirillales, which comprised more than 60% of the metagenomic data generated from the DWH oil plume. This suggests that Oceanospirillales might play a less significant role in the microbially mediated hydrocarbon conversion within the SBC seep oil compared to the DWH plume oil. We hypothesize that this difference results from the SBC oil seep being mostly anaerobic, while the DWH oil plume is aerobic. Within the Archaea, the phylum Euryarchaeota, recruited more than 95% of the assembled archaeal sequences from the SBC oil seep metagenome, with more than 50% of the sequences assigned to members of the orders Methanomicrobiales and Methanosarcinales. These orders contain organisms capable of anaerobic methanogenesis and methane oxidation (AOM) and we hypothesize that these orders - and their metabolic capabilities - may be fundamental to the ecology of the SBC oil seep.", "title": "Metagenomic analysis of microbial consortium from natural crude oil that seeps into the marine ecosystem offshore Southern California" }, { "docid": "11244195", "text": "MOTIVATION Accurate alignment of high-throughput RNA-seq data is a challenging and yet unsolved problem because of the non-contiguous transcript structure, relatively short read lengths and constantly increasing throughput of the sequencing technologies. Currently available RNA-seq aligners suffer from high mapping error rates, low mapping speed, read length limitation and mapping biases. \n RESULTS To align our large (>80 billon reads) ENCODE Transcriptome RNA-seq dataset, we developed the Spliced Transcripts Alignment to a Reference (STAR) software based on a previously undescribed RNA-seq alignment algorithm that uses sequential maximum mappable seed search in uncompressed suffix arrays followed by seed clustering and stitching procedure. STAR outperforms other aligners by a factor of >50 in mapping speed, aligning to the human genome 550 million 2 × 76 bp paired-end reads per hour on a modest 12-core server, while at the same time improving alignment sensitivity and precision. In addition to unbiased de novo detection of canonical junctions, STAR can discover non-canonical splices and chimeric (fusion) transcripts, and is also capable of mapping full-length RNA sequences. Using Roche 454 sequencing of reverse transcription polymerase chain reaction amplicons, we experimentally validated 1960 novel intergenic splice junctions with an 80-90% success rate, corroborating the high precision of the STAR mapping strategy. AVAILABILITY AND IMPLEMENTATION STAR is implemented as a standalone C++ code. STAR is free open source software distributed under GPLv3 license and can be downloaded from http://code.google.com/p/rna-star/.", "title": "STAR: ultrafast universal RNA-seq aligner." }, { "docid": "15960670", "text": "The centromere is a chromatin region that serves as the spindle attachment point and directs accurate inheritance of eukaryotic chromosomes during cell divisions. However, the mechanism by which the centromere assembles and stabilizes at a specific genomic region is not clear. The de novo formation of a human/mammalian artificial chromosome (HAC/MAC) with a functional centromere assembly requires the presence of alpha-satellite DNA containing binding motifs for the centromeric CENP-B protein. We demonstrate here that de novo centromere assembly on HAC/MAC is dependent on CENP-B. In contrast, centromere formation is suppressed in cells expressing CENP-B when alpha-satellite DNA was integrated into a chromosomal site. Remarkably, on those integration sites CENP-B enhances histone H3-K9 trimethylation and DNA methylation, thereby stimulating heterochromatin formation. Thus, we propose that CENP-B plays a dual role in centromere formation, ensuring de novo formation on DNA lacking a functional centromere but preventing the formation of excess centromeres on chromosomes.", "title": "CENP-B Controls Centromere Formation Depending on the Chromatin Context" }, { "docid": "14275671", "text": "The similarity in the three-dimensional structures of homologous proteins imposes strong constraints on their sequence variability. It has long been suggested that the resulting correlations among amino acid compositions at different sequence positions can be exploited to infer spatial contacts within the tertiary protein structure. Crucial to this inference is the ability to disentangle direct and indirect correlations, as accomplished by the recently introduced Direct Coupling Analysis (DCA) (Weigt et al. (2009) Proc Natl Acad Sci 106:67). Here we develop a computationally efficient implementation of DCA, which allows us to evaluate the accuracy of contact prediction by DCA for a large number of protein domains, based purely on sequence information. DCA is shown to yield a large number of correctly predicted contacts, recapitulating the global structure of the contact map for the majority of the protein domains examined. Furthermore, our analysis captures clear signals beyond intra- domain residue contacts, arising, e.g., from alternative protein conformations, ligand- mediated residue couplings, and inter-domain interactions in protein oligomers. Our findings suggest that contacts predicted by DCA can be used as a reliable guide to facilitate computational predictions of alternative protein conformations, protein complex formation, and even the de novo prediction of protein domain structures, provided the existence of a large number of homologous sequences which are being rapidly made available due to advances in genome sequencing.", "title": "Direct-coupling analysis of residue co-evolution captures native contacts across many protein families" }, { "docid": "20045514", "text": "Although important for gene regulation, most studies of genome organization use either fluorescence in situ hybridization (FISH) or chromosome conformation capture (3C) methods. FISH directly visualizes the spatial relationship of sequences but is usually applied to a few loci at a time. The frequency at which sequences are ligated together by formaldehyde cross-linking can be measured genome-wide by 3C methods, with higher frequencies thought to reflect shorter distances. FISH and 3C should therefore give the same views of genome organization, but this has not been tested extensively. We investigated the murine HoxD locus with 3C carbon copy (5C) and FISH in different developmental and activity states and in the presence or absence of epigenetic regulators. We identified situations in which the two data sets are concordant but found other conditions under which chromatin topographies extrapolated from 5C or FISH data are not compatible. We suggest that products captured by 3C do not always reflect spatial proximity, with ligation occurring between sequences located hundreds of nanometers apart, influenced by nuclear environment and chromatin composition. We conclude that results obtained at high resolution with either 3C methods or FISH alone must be interpreted with caution and that views about genome organization should be validated by independent methods.", "title": "Spatial genome organization: contrasting views from chromosome conformation capture and fluorescence in situ hybridization." }, { "docid": "2576811", "text": "Epithelial integrity is vitally important, and its deregulation causes early stage cancer. De novo formation of an adherens junction (AJ) between single epithelial cells requires coordinated, spatial actin dynamics, but the mechanisms steering nascent actin polymerization for cell-cell adhesion initiation are not well understood. Here we investigated real-time actin assembly during daughter cell-cell adhesion formation in human breast epithelial cells in 3D environments. We identify formin-like 2 (FMNL2) as being specifically required for actin assembly and turnover at newly formed cell-cell contacts as well as for human epithelial lumen formation. FMNL2 associates with components of the AJ complex involving Rac1 activity and the FMNL2 C terminus. Optogenetic control of Rac1 in living cells rapidly drove FMNL2 to epithelial cell-cell contact zones. Furthermore, Rac1-induced actin assembly and subsequent AJ formation critically depends on FMNL2. These data uncover FMNL2 as a driver for human epithelial AJ formation downstream of Rac1.", "title": "Junctional actin assembly is mediated by Formin-like 2 downstream of Rac1" }, { "docid": "152245", "text": "The genomic RNA of an alphavirus encodes four different nonstructural proteins, nsP1, nsP2, nsP3, and nsP4. The polyprotein P123 is produced when translation terminates at an opal termination codon between nsP3 and nsP4. The polyprotein P1234 is produced when translational readthrough occurs or when the opal termination codon has been replaced by a sense codon in the alphavirus genome. Evolutionary pressures appear to have maintained genomic sequences encoding both a stop codon (opal) and an open reading frame (arginine) as a general feature of the O'nyong-nyong virus (ONNV) genome, indicating that both are required at some point. Alternate replication of ONNVs in both vertebrate and invertebrate hosts may determine predominance of a particular codon at this locus in the viral quasispecies. However, no systematic study has previously tested this hypothesis in whole animals. We report here the results of the first study to investigate in a natural mosquito host the functional significance of the opal stop codon in an alphavirus genome. We used a full-length cDNA clone of ONNV to construct a series of mutants in which the arginine between nsP3 and nsP4 was replaced with an opal, ochre, or amber stop codon. The presence of an opal stop codon upstream of nsP4 nearly doubled (75.5%) the infectivity of ONNV over that of virus possessing a codon for the amino acid arginine at the corresponding position (39.8%). Although the frequency with which the opal virus disseminated from the mosquito midgut did not differ significantly from that of the arginine virus on days 8 and 10, dissemination did began earlier in mosquitoes infected with the opal virus. Although a clear fitness advantage is provided to ONNV by the presence of an opal codon between nsP3 and nsP4 in Anopheles gambiae, sequence analysis of ONNV RNA extracted from mosquito bodies and heads indicated codon usage at this position corresponded with that of the virus administered in the blood meal. These results suggest that while selection of ONNV variants is occurring, de novo mutation at the position between nsP3 and nsP4 does not readily occur in the mosquito. Taken together, these results suggest that the primary fitness advantage provided to ONNV by the presence of an opal codon between nsP3 and nsP4 is related to mosquito infectivity.", "title": "Effects of an opal termination codon preceding the nsP4 gene sequence in the O'Nyong-Nyong virus genome on Anopheles gambiae infectivity." }, { "docid": "31634628", "text": "Cell-free tumor DNA (ctDNA) has the potential to enable non-invasive diagnostic tests for personalized medicine in providing similar molecular information as that derived from invasive tumor biopsies. The histology-independent phase II SHIVA trial matches patients with targeted therapeutics based on previous screening of multiple somatic mutations using metastatic biopsies. To evaluate the utility of ctDNA in this trial, as an ancillary study we performed de novo detection of somatic mutations using plasma DNA compared to metastasis biopsies in 34 patients covering 18 different tumor types, scanning 46 genes and more than 6800 COSMIC mutations with a multiplexed next-generation sequencing panel. In 27 patients, 28 of 29 mutations identified in metastasis biopsies (97%) were detected in matched ctDNA. Among these 27 patients, one additional mutation was found in ctDNA only. In the seven other patients, mutation detection from metastasis biopsy failed due to inadequate biopsy material, but was successful in all plasma DNA samples providing three more potential actionable mutations. These results suggest that ctDNA analysis is a potential alternative and/or replacement to analyses using costly, harmful and lengthy tissue biopsies of metastasis, irrespective of cancer type and metastatic site, for multiplexed mutation detection in selecting personalized therapies based on the patient's tumor genetic content.", "title": "Circulating tumor DNA as a non-invasive substitute to metastasis biopsy for tumor genotyping and personalized medicine in a prospective trial across all tumor types." }, { "docid": "19138874", "text": "The biogenesis of the many functional compartments contained in the mammalian cell nucleus is poorly understood. More specifically, little is known regarding the initial nucleation step required for nuclear body formation. Here we show that RNA can function as a structural element and a nucleator of nuclear bodies. We find that several types of coding and noncoding RNAs are sufficient to de novo assemble, and are physiologically enriched in, histone locus bodies (with associated Cajal bodies), nuclear speckles, paraspeckles and nuclear stress bodies. Formation of nuclear bodies occurs through recruitment and accumulation of proteins resident in the nuclear bodies by nucleating RNA. These results demonstrate that transcription is a driving force in nuclear body formation and RNA transcripts can function as a scaffold in the formation of major nuclear bodies. Together, these data suggest that RNA-primed biogenesis of nuclear bodies is a general principle of nuclear organization.", "title": "Nucleation of nuclear bodies by RNA" }, { "docid": "22186938", "text": "Human artificial chromosomes (HACs) are autonomous molecules that can function and segregate as normal chromosomes in human cells. De novo HACs have successfully been used as gene expression vectors to complement genetic deficiencies in human cultured cells. HACs now offer the possibility of studying the regulation and expression of large genes in a variety of cell types from different tissues and correcting gene deficiencies caused by human inherited diseases. Complementary gene expression studies in mice, especially in mouse models of human genetic diseases, are also important in determining if large human transgenes can be expressed appropriately from artificial chromosomes. Toward this aim we are establishing artificial chromosomes in murine cells as novel gene expression vectors. Initially we transferred HAC vectors into murine cells, but were unable to generate de novo HACs at a reasonable frequency. We then transferred HACs previously established in human HT1080 cells to three different murine cell types by microcell fusion, followed by positive selection. We observed that the HACs in murine cells bound centromere protein C (CENP-C), a marker of active centromeres, and were detected under selection but rapidly lost when selection was removed. These results suggest that the HACs maintain at least a partially functional centromere complex in murine cells, but other factors are required for stability and segregation. Artificial chromosomes containing mouse centromeric sequences may be required for better stability and maintenance in murine cells.", "title": "Human artificial chromosomes containing chromosome 17 alphoid DNA maintain an active centromere in murine cells but are not stable." }, { "docid": "18361917", "text": "PURPOSE The adult newt can regenerate lens from pigmented epithelial cells (PECs) of the dorsal iris via dedifferentiation. The purpose of this research is to obtain sequence resources for a newt lens regeneration study and to obtain insights of dedifferentiation at the molecular level. \n METHODS mRNA was purified from iris during dedifferentiation and its cDNA library was constructed. From the cDNA library 10,449 clones were sequenced and analyzed. \n RESULTS From 10,449 reads, 780 contigs and 1,666 singlets were annotated. The presence of several cancer- and apoptosis-related genes during newt dedifferentiation was revealed. Moreover, several candidate genes, which might participate in reprogramming during dedifferentiation, were also found. \n CONCLUSIONS The expression of cancer- and apoptosis-related genes could be hallmarks during dedifferentiation. The expression sequence tag (EST) resource is useful for the future study of newt dedifferentiation, and the sequence information is available in GenBank (accession numbers; FS290155-FS300559).", "title": "Expression profiles during dedifferentiation in newt lens regeneration revealed by expressed sequence tags" }, { "docid": "84784389", "text": "When small RNA is sequenced on current sequencing machines, the resulting reads are usually longer than the RNA and therefore contain parts of the 3' adapter. That adapter must be found and removed error-tolerantly from each read before read mapping. Previous solutions are either hard to use or do not offer required features, in particular support for color space data. As an easy to use alternative, we developed the command-line tool cutadapt, which supports 454, Illumina and SOLiD (color space) data, offers two adapter trimming algorithms, and has other useful features. Cutadapt, including its MIT-licensed source code, is available for download at http://code.google.com/p/cutadapt/", "title": "Cutadapt removes adapter sequences from high-throughput sequencing reads" } ]

[ { "docid": "3701541", "text": "Hepatic stellate cells (HSCs) play critical roles in liver fibrosis and hepatocellular carcinoma (HCC). Vitamin D receptor (VDR) activation in HSCs inhibits liver inflammation and fibrosis. We found that p62/SQSTM1, a protein upregulated in liver parenchymal cells but downregulated in HCC-associated HSCs, negatively controls HSC activation. Total body or HSC-specific p62 ablation potentiates HSCs and enhances inflammation, fibrosis, and HCC progression. p62 directly interacts with VDR and RXR promoting their heterodimerization, which is critical for VDR:RXR target gene recruitment. Loss of p62 in HSCs impairs the repression of fibrosis and inflammation by VDR agonists. This demonstrates that p62 is a negative regulator of liver inflammation and fibrosis through its ability to promote VDR signaling in HSCs, whose activation supports HCC.", "title": "p62/SQSTM1 by Binding to Vitamin D Receptor Inhibits Hepatic Stellate Cell Activity, Fibrosis, and Liver Cancer." } ]

[ { "docid": "26735905", "text": "The tumor microenvironment plays a critical role in cancer progression, but the precise mechanisms by which stromal cells influence the epithelium are poorly understood. Here we show that p62 levels were reduced in the stroma of several tumors and that its loss in the tumor microenvironment or stromal fibroblasts resulted in increased tumorigenesis of epithelial prostate cancer cells. The mechanism involves the regulation of cellular redox through an mTORC1/c-Myc pathway of stromal glucose and amino acid metabolism, resulting in increased stromal IL-6 production, which is required for tumor promotion in the epithelial compartment. Thus, p62 is an anti-inflammatory tumor suppressor that acts through the modulation of metabolism in the tumor stroma.", "title": "Metabolic reprogramming of stromal fibroblasts through p62-mTORC1 signaling promotes inflammation and tumorigenesis." }, { "docid": "25576204", "text": "Malignant cells often display defects in autophagy, an evolutionarily conserved pathway for degrading long-lived proteins and cytoplasmic organelles. However, as yet, there is no genetic evidence for a role of autophagy genes in tumor suppression. The beclin 1 autophagy gene is monoallelically deleted in 40-75% of cases of human sporadic breast, ovarian, and prostate cancer. Therefore, we used a targeted mutant mouse model to test the hypothesis that monoallelic deletion of beclin 1 promotes tumorigenesis. Here we show that heterozygous disruption of beclin 1 increases the frequency of spontaneous malignancies and accelerates the development of hepatitis B virus-induced premalignant lesions. Molecular analyses of tumors in beclin 1 heterozygous mice show that the remaining wild-type allele is neither mutated nor silenced. Furthermore, beclin 1 heterozygous disruption results in increased cellular proliferation and reduced autophagy in vivo. These findings demonstrate that beclin 1 is a haplo-insufficient tumor-suppressor gene and provide genetic evidence that autophagy is a novel mechanism of cell-growth control and tumor suppression. Thus, mutation of beclin 1 or other autophagy genes may contribute to the pathogenesis of human cancers.", "title": "Promotion of tumorigenesis by heterozygous disruption of the beclin 1 autophagy gene." }, { "docid": "8702697", "text": "AIMS Tumor microenvironment is a strong determinant for the acquisition of metastatic potential of cancer cells. We have recently demonstrated that cancer-associated fibroblasts (CAFs) elicit a redox-dependent epithelial-mesenchymal transition (EMT) in prostate cancer (PCa) cells, driven by cycloxygenase-2/hypoxia-inducible factor-1 (HIF-1)/nuclear factor-κB pathway and enhancing tumor aggressiveness. Here, we investigated the involvement of microRNAs (miRNAs) in tumor-stroma interplay to identify possible tools to counteract oxidative stress and metastasis dissemination. \n RESULTS We found that miR-205 is the most downmodulated miRNA in PCa cells upon CAF stimulation, due to direct transcriptional repression by HIF-1, a known redox-sensitive transcription factor. Rescue experiments demonstrated that ectopic miR-205 overexpression in PCa cells counteracts CAF-induced EMT, thus impairing enhancement of cell invasion, acquisition of stem cell traits, tumorigenicity, and metastatic dissemination. In addition, miR-205 blocks tumor-driven activation of surrounding fibroblasts by reducing pro-inflammatory cytokine secretion. INNOVATION Overall, such findings suggest miR-205 as a brake against PCa metastasis by blocking both the afferent and efferent arms of the circuit between tumor cells and associated fibroblasts, thus interrupting the pro-oxidant and pro-inflammatory circuitries engaged by reactive stroma. \n CONCLUSION The evidence that miR-205 replacement in PCa cells is able not only to prevent but also to revert the oxidative/pro-inflammatory axis leading to EMT induced by CAFs sets the rationale for developing miRNA-based approaches to prevent and treat metastatic disease.", "title": "miR-205 hinders the malignant interplay between prostate cancer cells and associated fibroblasts." }, { "docid": "24349992", "text": "Loss of stromal fibroblast caveolin-1 (Cav-1) is a powerful single independent predictor of poor prognosis in human breast cancer patients, and is associated with early tumor recurrence, lymph node metastasis and tamoxifen-resistance. We developed a novel co-culture system to understand the mechanism(s) by which a loss of stromal fibroblast Cav-1 induces a \"lethal tumor micro-environment. \" Here, we propose a new paradigm to explain the powerful prognostic value of stromal Cav-1. In this model, cancer cells induce oxidative stress in cancer-associated fibroblasts, which then acts as a \"metabolic\" and \"mutagenic\" motor to drive tumor-stroma co-evolution, DNA damage and aneuploidy in cancer cells. More specifically, we show that an acute loss of Cav-1 expression leads to mitochondrial dysfunction, oxidative stress and aerobic glycolysis in cancer associated fibroblasts. Also, we propose that defective mitochondria are removed from cancer-associated fibroblasts by autophagy/mitophagy that is induced by oxidative stress. As a consequence, cancer associated fibroblasts provide nutrients (such as lactate) to stimulate mitochondrial biogenesis and oxidative metabolism in adjacent cancer cells (the \"Reverse Warburg Effect\"). We provide evidence that oxidative stress in cancer-associated fibroblasts is sufficient to induce genomic instability in adjacent cancer cells, via a bystander effect, potentially increasing their aggressive behavior. Finally, we directly demonstrate that nitric oxide (NO) over-production, secondary to Cav-1 loss, is the root cause for mitochondrial dysfunction in cancer associated fibroblasts. In support of this notion, treatment with anti-oxidants (such as N-acetyl-cysteine, metformin and quercetin) or NO inhibitors (L-NAME) was sufficient to reverse many of the cancer-associated fibroblast phenotypes that we describe. Thus, cancer cells use \"oxidative stress\" in adjacent fibroblasts (i) as an \"engine\" to fuel their own survival via the stromal production of nutrients and (ii) to drive their own mutagenic evolution towards a more aggressive phenotype, by promoting genomic instability. We also present evidence that the \"field effect\" in cancer biology could also be related to the stromal production of ROS and NO species. eNOS-expressing fibroblasts have the ability to downregulate Cav-1 and induce mitochondrial dysfunction in adjacent fibroblasts that do not express eNOS. As such, the effects of stromal oxidative stress can be laterally propagated, amplified and are effectively \"contagious\"--spread from cell-to-cell like a virus--creating an \"oncogenic/mutagenic\" field promoting widespread DNA damage.", "title": "Oxidative stress in cancer associated fibroblasts drives tumor-stroma co-evolution: A new paradigm for understanding tumor metabolism, the field effect and genomic instability in cancer cells." }, { "docid": "10463997", "text": "Objectives: Autophagy is a highly regulated process that has an important role in the control of a wide range of cellular functions, such as organelle recycling, nutrient availability and tissue differentiation. A recent study has shown an increased autophagic activity in the adipose tissue of obese subjects, and a role for autophagy in obesity-associated insulin resistance was proposed. Body mass reduction is the most efficient approach to tackle insulin resistance in over-weight subjects; however, the impact of weight loss in adipose tissue autophagy is unknown. Subjects:Adipose tissue autophagy was evaluated in mice and humans. Results:First, a mouse model of diet-induced obesity and diabetes was maintained on a 15-day, 40% caloric restriction. At baseline, markers of autophagy were increased in obese mice as compared with lean controls. Upon caloric restriction, autophagy increased in the lean mice, whereas it decreased in the obese mice. The reintroduction of ad libitum feeding was sufficient to rapidly reduce autophagy in the lean mice and increase autophagy in the obese mice. In the second part of the study, autophagy was evaluated in the subcutaneous adipose tissue of nine obese-non-diabetic and six obese-diabetic subjects undergoing bariatric surgery for body mass reduction. Specimens were collected during the surgery and approximately 1 year later. Markers of systemic inflammation, such as tumor necrosis factor-1α, interleukin (IL)-6 and IL-1β were evaluated. As in the mouse model, human obesity was associated with increased autophagy, and body mass reduction led to an attenuation of autophagy in the adipose tissue. Conclusion:Obesity and caloric overfeeding are associated with the defective regulation of autophagy in the adipose tissue. The studies in obese-diabetic subjects undergoing improved metabolic control following calorie restriction suggest that autophagy and inflammation are regulated independently.", "title": "Defective regulation of adipose tissue autophagy in obesity" }, { "docid": "31882215", "text": "We describe robust induction of autophagy during the reprogramming of mouse fibroblasts to induced pluripotent stem cells by four reprogramming factors (Sox2, Oct4, Klf4 and c-Myc), henceforth 4F. This process occurs independently of p53 activation, and is mediated by the synergistic downregulation of mechanistic target of rapamycin complex 1 (mTORC1) and the induction of autophagy-related genes. The 4F coordinately repress mTORC1, but bifurcate in their regulation of autophagy-related genes, with Klf4 and c-Myc inducing them but Sox2 and Oct4 inhibiting them. On one hand, inhibition of mTORC1 facilitates reprogramming by promoting cell reshaping (mitochondrial remodelling and cell size reduction). On the other hand, mTORC1 paradoxically impairs reprogramming by triggering autophagy. Autophagy does not participate in cell reshaping in reprogramming but instead degrades p62, whose accumulation in autophagy-deficient cells facilitates reprogramming. Our results thus reveal a complex signalling network involving mTORC1 inhibition and autophagy induction in the early phase of reprogramming, whose delicate balance ultimately determines reprogramming efficiency.", "title": "Autophagy and mTORC1 regulate the stochastic phase of somatic cell reprogramming" }, { "docid": "27647593", "text": "Cancer cells do not exist as pure homogeneous populations in vivo. Instead they are embedded in \"cancer cell nests\" that are surrounded by stromal cells, especially cancer associated fibroblasts. Thus, it is not unreasonable to suspect that stromal fibroblasts could influence the metabolism of adjacent cancer cells, and visa versa. In accordance with this idea, we have recently proposed that the Warburg effect in cancer cells may be due to culturing cancer cells by themselves, out of their normal stromal context or tumor microenvironment. In fact, when cancer cells are co-cultured with fibroblasts, then cancer cells increase their mitochondrial mass, while fibroblasts lose their mitochondria. An in depth analysis of this phenomenon reveals that aggressive cancer cells are \"parasites\" that use oxidative stress as a \"weapon\" to extract nutrients from surrounding stromal cells. Oxidative stress in fibroblasts induces the autophagic destruction of mitochondria, by mitophagy. Then, stromal cells are forced to undergo aerobic glycolysis, and produce energy-rich nutrients (such as lactate and ketones) to \"feed\" cancer cells. This mechanism would allow cancer cells to seed anywhere, without blood vessels as a food source, as they could simply induce oxidative stress wherever they go, explaining how cancer cells survive during metastasis. We suggest that stromal catabolism, via autophagy and mitophagy, fuels the anabolic growth of tumor cells, promoting tumor progression and metastasis. We have previously termed this new paradigm \"The Autophagic Tumor Stroma Model of Cancer Metabolism\", or the \"Reverse Warburg Effect\". We also discuss how glutamine addiction (glutaminolysis) in cancer cells fits well with this new model, by promoting oxidative mitochondrial metabolism in aggressive cancer cells.", "title": "Stromal-epithelial metabolic coupling in cancer: integrating autophagy and metabolism in the tumor microenvironment." }, { "docid": "10024681", "text": "Deregulation of microRNA (miRNA) expression can have a critical role in carcinogenesis. Here we show in prostate cancer that miRNA-205 (miR-205) transcription is commonly repressed and the MIR-205 locus is hypermethylated. LOC642587, the MIR-205 host gene of unknown function, is also concordantly inactivated. We show that miR-205 targets mediator 1 (MED1, also called TRAP220 and PPARBP) for transcriptional silencing in normal prostate cells, leading to reduction in MED1 mRNA levels, and in total and active phospho-MED1 protein. Overexpression of miR-205 in prostate cancer cells negatively affects cell viability, consistent with a tumor suppressor function. We found that hypermethylation of the MIR-205 locus was strongly related with a decrease in miR-205 expression and an increase in MED1 expression in primary tumor samples (n=14), when compared with matched normal prostate (n=7). An expanded patient cohort (tumor n=149, matched normal n=30) also showed significant MIR-205 DNA methylation in tumors compared with normal, and MIR-205 hypermethylation is significantly associated with biochemical recurrence (hazard ratio=2.005, 95% confidence interval (1.109, 3.625), P=0.02), in patients with low preoperative prostate specific antigen. In summary, these results suggest that miR-205 is an epigenetically regulated tumor suppressor that targets MED1 and may provide a potential biomarker in prostate cancer management.", "title": "Epigenetic-induced repression of microRNA-205 is associated with MED1 activation and a poorer prognosis in localized prostate cancer" }, { "docid": "8425533", "text": "A defining feature of mitochondria is their maternal mode of inheritance. However, little is understood about the cellular mechanism through which paternal mitochondria, delivered from sperm, are eliminated from early mammalian embryos. Autophagy has been implicated in nematodes, but whether this mechanism is conserved in mammals has been disputed. Here, we show that cultured mouse fibroblasts and pre-implantation embryos use a common pathway for elimination of mitochondria. Both situations utilize mitophagy, in which mitochondria are sequestered by autophagosomes and delivered to lysosomes for degradation. The E3 ubiquitin ligases PARKIN and MUL1 play redundant roles in elimination of paternal mitochondria. The process is associated with depolarization of paternal mitochondria and additionally requires the mitochondrial outer membrane protein FIS1, the autophagy adaptor P62, and PINK1 kinase. Our results indicate that strict maternal transmission of mitochondria relies on mitophagy and uncover a collaboration between MUL1 and PARKIN in this process.", "title": "Elimination of paternal mitochondria in mouse embryos occurs through autophagic degradation dependent on PARKIN and MUL1" }, { "docid": "23509593", "text": "BACKGROUND Prostate development and maintenance in the adult results from an interaction of stromal and glandular components. Androgens can drive this process by direct action on the stroma. We investigated whether there was a direct link between androgens and another key regulator of stromal cells, intracellular Ca2+ ([Ca2+ ]i ). \n METHODS Prostate stromal cells were freshly obtained and cultures derived from patients with benign prostatic hyperplasia. Gene expression in dihydrotestosterone treated and untreated cells was compared using Affymetrix gene expression arrays and Ca2+ regulated features were identified by Gene Ontology (GO). Changes in [Ca2+]i were determined in Fluo-4 loaded cells. Androgen regulation was confirmed by chromatin immunoprecipitaion. \n RESULTS Stromal cell cultures were sorted for expression of integrin α1 β1 , which enriched for cells expressing the androgen receptor (AR). We identified key functional categories, within the androgen-induced gene expression signature, focusing on genes involved in calcium signaling. From this analysis, stromal interaction molecule-1 (STIM1) was identified as a significantly differentially expressed gene with four relevant associated GO terms. DNA sequence analysis showed that the promoter region of STIM1 contained putative androgen response element sequences in which AR binding ability of STIM1 was confirmed. Androgens directly regulated STIM1 expression and STIM1 effects on store-operated calcium entry were inhibited by STIM1 knock-down. Reduced STIM1 expression in prostate stromal cells led to a reduction in basal Ca2+ levels, the amount of Ca2+ released by thapsigargin and a reduction in store filling following TG-induced store depletion. \n CONCLUSIONS These results indicate that androgens modulate [Ca2+]i through the direct regulation of the STIM1 gene by AR binding to the STIM1 promoter.", "title": "The calcium sensor STIM1 is regulated by androgens in prostate stromal cells." }, { "docid": "24632480", "text": "Aberrant protein misfolding may contribute to the pathogenesis of amyotrophic lateral sclerosis (ALS) but the detailed mechanisms are largely unknown. Our previous study has shown that autophagy is altered in the mouse model of ALS. In the present study, we systematically investigated the correlation of the autophagic alteration with the motor neurons (MNs) degeneration in the ALS mice. We have demonstrated that the autophagic protein marker LC3-II is markedly and specifically increased in the spinal cord MNs of the ALS mice. Electron microscopy and immunochemistry studies have shown that autophagic vacuoles are significantly accumulated in the dystrophic axons of spinal cord MNs of the ALS mice. All these changes in the ALS mice appear at the age of 90 d when the ALS mice display modest clinical symptoms; and they become prominent at the age of 120 d. The clinical symptoms are correlated with the progression of MNs degeneration. Moreover, we have found that p62/SQSTM1 is accumulated progressively in the spinal cord, indicating that the possibility of impaired autophagic flux in the SOD1(G93A) mice. Furthermore, to our surprise, we have found that treatment with autophagy enhancer rapamycin accelerates the MNs degeneration, shortens the life span of the ALS mice, and has no obvious effects on the accumulation of SOD1 aggregates. In addition, we have demonstrated that rapamycin treatment in the ALS mice causes more severe mitochondrial impairment, higher Bax levels and greater caspase-3 activation. These findings suggest that selective degeneration of MNs is associated with the impairment of the autophagy pathway and that rapamycin treatment may exacerbate the pathological processing through apoptosis and other mechanisms in the ALS mice.", "title": "Rapamycin treatment augments motor neuron degeneration in SOD1(G93A) mouse model of amyotrophic lateral sclerosis." }, { "docid": "41710132", "text": "The tumor suppressor PML (promyelocytic leukemia protein) regulates cellular senescence and terminal differentiation, two processes that implicate a permanent exit from the cell cycle. Here, we show that the mechanism by which PML induces a permanent cell cycle exit and activates p53 and senescence involves a recruitment of E2F transcription factors bound to their promoters and the retinoblastoma (Rb) proteins to PML nuclear bodies enriched in heterochromatin proteins and protein phosphatase 1α. Blocking the functions of the Rb protein family or adding back E2Fs to PML-expressing cells can rescue their defects in E2F-dependent gene expression and cell proliferation, inhibiting the senescent phenotype. In benign prostatic hyperplasia, a neoplastic disease that displays features of senescence, PML was found to be up-regulated and forming nuclear bodies. In contrast, PML bodies were rarely visualized in prostate cancers. The newly defined PML/Rb/E2F pathway may help to distinguish benign tumors from cancers, and suggest E2F target genes as potential targets to induce senescence in human tumors.", "title": "Regulation of E2Fs and senescence by PML nuclear bodies." }, { "docid": "7548577", "text": "In the yeast Saccharomyces cerevisiae, glycogen is accumulated as a carbohydrate reserve when cells are deprived of nutrients. Yeast mutated in SNF1, a gene encoding a protein kinase required for glucose derepression, has diminished glycogen accumulation and concomitant inactivation of glycogen synthase. Restoration of synthesis in an snf1 strain results only in transient glycogen accumulation, implying the existence of other SNF1-dependent controls of glycogen storage. A genetic screen revealed that two genes involved in autophagy, APG1 and APG13, may be regulated by SNF1. Increased autophagic activity was observed in wild-type cells entering the stationary phase, but this induction was impaired in an snf1 strain. Mutants defective for autophagy were able to synthesize glycogen upon approaching the stationary phase, but were unable to maintain their glycogen stores, because subsequent synthesis was impaired and degradation by phosphorylase, Gph1p, was enhanced. Thus, deletion of GPH1 partially reversed the loss of glycogen accumulation in autophagy mutants. Loss of the vacuolar glucosidase, SGA1, also protected glycogen stores, but only very late in the stationary phase. Gph1p and Sga1p may therefore degrade physically distinct pools of glycogen. Pho85p is a cyclin-dependent protein kinase that antagonizes SNF1 control of glycogen synthesis. Induction of autophagy in pho85 mutants entering the stationary phase was exaggerated compared to the level in wild-type cells, but was blocked in apg1 pho85 mutants. We propose that Snf1p and Pho85p are, respectively, positive and negative regulators of autophagy, probably via Apg1 and/or Apg13. Defective glycogen storage in snf1 cells can be attributed to both defective synthesis upon entry into stationary phase and impaired maintenance of glycogen levels caused by the lack of autophagy.", "title": "Antagonistic Controls of Autophagy and Glycogen Accumulation by Snf1p, the Yeast Homolog of AMP-Activated Protein Kinase, and the Cyclin-Dependent" }, { "docid": "1084345", "text": "Chaperone-mediated autophagy (CMA), a selective mechanism for degradation of cytosolic proteins in lysosomes, contributes to the removal of altered proteins as part of the cellular quality-control systems. We have previously found that CMA activity declines in aged organisms and have proposed that this failure in cellular clearance could contribute to the accumulation of altered proteins, the abnormal cellular homeostasis and, eventually, the functional loss characteristic of aged organisms. To determine whether these negative features of aging can be prevented by maintaining efficient autophagic activity until late in life, in this work we have corrected the CMA defect in aged rodents. We have generated a double transgenic mouse model in which the amount of the lysosomal receptor for CMA, previously shown to decrease in abundance with age, can be modulated. We have analyzed in this model the consequences of preventing the age-dependent decrease in receptor abundance in aged rodents at the cellular and organ levels. We show here that CMA activity is maintained until advanced ages if the decrease in the receptor abundance is prevented and that preservation of autophagic activity is associated with lower intracellular accumulation of damaged proteins, better ability to handle protein damage and improved organ function.", "title": "Restoration of chaperone-mediated autophagy in aging liver improves cellular maintenance and hepatic function" }, { "docid": "24581365", "text": "CONTEXT The appropriate therapy for men with clinically localized prostate cancer is uncertain. A recent study suggested an increasing prostate cancer mortality rate for men who are alive more than 15 years following diagnosis. \n OBJECTIVE To estimate 20-year survival based on a competing risk analysis of men who were diagnosed with clinically localized prostate cancer and treated with observation or androgen withdrawal therapy alone, stratified by age at diagnosis and histological findings. \n DESIGN, SETTING, AND PATIENTS A retrospective population-based cohort study using Connecticut Tumor Registry data supplemented by hospital record and histology review of 767 men aged 55 to 74 years with clinically localized prostate cancer diagnosed between January 1, 1971, and December 31, 1984. Patients were treated with either observation or immediate or delayed androgen withdrawal therapy, with a median observation of 24 years. \n MAIN OUTCOME MEASURES Probability of mortality from prostate cancer or other competing medical conditions, given a patient's age at diagnosis and tumor grade. \n RESULTS The prostate cancer mortality rate was 33 per 1000 person-years during the first 15 years of follow-up (95% confidence interval [CI], 28-38) and 18 per 1000 person-years after 15 years of follow-up (95% CI, 10-29). The mortality rates for these 2 follow-up periods were not statistically different, after adjusting for differences in tumor histology (rate ratio, 1.1; 95% CI, 0.6-1.9). Men with low-grade prostate cancers have a minimal risk of dying from prostate cancer during 20 years of follow-up (Gleason score of 2-4, 6 deaths per 1000 person-years; 95% CI, 2-11). Men with high-grade prostate cancers have a high probability of dying from prostate cancer within 10 years of diagnosis (Gleason score of 8-10, 121 deaths per 1000 person-years; 95% CI, 90-156). Men with Gleason score of 5 or 6 tumors have an intermediate risk of prostate cancer death. \n CONCLUSION The annual mortality rate from prostate cancer appears to remain stable after 15 years from diagnosis, which does not support aggressive treatment for localized low-grade prostate cancer.", "title": "20-year outcomes following conservative management of clinically localized prostate cancer." }, { "docid": "25513319", "text": "Metabolic pathway reprogramming is a hallmark of cancer cell growth and survival and supports the anabolic and energetic demands of these rapidly dividing cells. The underlying regulators of the tumor metabolic program are not completely understood; however, these factors have potential as cancer therapy targets. Here, we determined that upregulation of the oncogenic transcriptional coregulator steroid receptor coactivator 2 (SRC-2), also known as NCOA2, drives glutamine-dependent de novo lipogenesis, which supports tumor cell survival and eventual metastasis. SRC-2 was highly elevated in a variety of tumors, especially in prostate cancer, in which SRC-2 was amplified and overexpressed in 37% of the metastatic tumors evaluated. In prostate cancer cells, SRC-2 stimulated reductive carboxylation of α-ketoglutarate to generate citrate via retrograde TCA cycling, promoting lipogenesis and reprogramming of glutamine metabolism. Glutamine-mediated nutrient signaling activated SRC-2 via mTORC1-dependent phosphorylation, which then triggered downstream transcriptional responses by coactivating SREBP-1, which subsequently enhanced lipogenic enzyme expression. Metabolic profiling of human prostate tumors identified a massive increase in the SRC-2-driven metabolic signature in metastatic tumors compared with that seen in localized tumors, further implicating SRC-2 as a prominent metabolic coordinator of cancer metastasis. Moreover, SRC-2 inhibition in murine models severely attenuated the survival, growth, and metastasis of prostate cancer. Together, these results suggest that the SRC-2 pathway has potential as a therapeutic target for prostate cancer.", "title": "Coactivator SRC-2-dependent metabolic reprogramming mediates prostate cancer survival and metastasis." }, { "docid": "982650", "text": "BACKGROUND & AIMS Tumor cells survive hypoxic conditions by inducing autophagy. We investigated the roles of microRNAs (miRNAs) in regulating autophagy of hepatocellular carcinoma (HCC) cells under hypoxic conditions. \n METHODS We used gain- and loss-of-function methods to evaluate the effect of miRNAs on autophagy in human HCC cell lines (Huh7 and Hep3B) under hypoxic conditions. Autophagy was quantified by immunoblot, immunofluoresence, and transmission electron microscopy analyses, and after incubation of cells with bafilomycin A1. We used a luciferase reporter assay to confirm associations between miRNAs and their targets. We analyzed growth of HCC xenograft tumors in nude mice. \n RESULTS miR-375 was down-regulated in HCC cells and tissues; it inhibited autophagy under hypoxic conditions by suppressing the conversion of LC3I to LC3II and thereby autophagic flux. The ability of miR-375 to inhibit autophagy was independent of its ability to regulate 3'-phosphoinositide-dependent protein kinase-1-AKT-mammalian target of rapamycin signaling, but instead involved suppression of ATG7, an autophagy-associated gene. miR-375 bound directly to a predicted site in the 3' untranslated region of ATG7. Up-regulating miR-375 or down-regulating ATG7 inhibited mitochondrial autophagy of HCC cells, reduced the elimination of damaged mitochondria under hypoxia, increased release of mitochondrial apoptotic proteins, and reduced viability of HCC cells. In mice, xenograft tumors that expressed miR-375 had fewer autophagic cells, larger areas of necrosis, and grew more slowly than tumors from HCC cells that expressed lower levels of miR-375. \n CONCLUSIONS miR-375 inhibits autophagy by reducing expression of ATG7 and impairs viability of HCC cells under hypoxic conditions in culture and in mice. miRNAs that inhibit autophagy of cancer cells might be developed as therapeutics.", "title": "miR-375 inhibits autophagy and reduces viability of hepatocellular carcinoma cells under hypoxic conditions." }, { "docid": "6790197", "text": "PURPOSE To accurately identify gene expression alterations that differentiate neoplastic from normal prostate epithelium using an approach that avoids contamination by unwanted cellular components and is not compromised by acute gene expression changes associated with tumor devascularization and resulting ischemia. EXPERIMENTAL DESIGN Approximately 3,000 neoplastic and benign prostate epithelial cells were isolated using laser capture microdissection from snap-frozen prostate biopsy specimens provided by 31 patients who subsequently participated in a clinical trial of preoperative chemotherapy. cDNA synthesized from amplified total RNA was hybridized to custom-made microarrays composed of 6,200 clones derived from the Prostate Expression Database. Expression differences for selected genes were verified using quantitative reverse transcription-PCR. \n RESULTS Comparative analyses identified 954 transcript alterations associated with cancer (q < 0.01%), including 149 differentially expressed genes with no known functional roles. Gene expression changes associated with ischemia and surgical removal of the prostate gland were absent. Genes up-regulated in prostate cancer were statistically enriched in categories related to cellular metabolism, energy use, signal transduction, and molecular transport. Genes down-regulated in prostate cancers were enriched in categories related to immune response, cellular responses to pathogens, and apoptosis. A heterogeneous pattern of androgen receptor expression changes was noted. In exploratory analyses, androgen receptor down-regulation was associated with a lower probability of cancer relapse after neoadjuvant chemotherapy followed by radical prostatectomy. \n CONCLUSIONS Assessments of tumor phenotypes based on gene expression for treatment stratification and drug targeting of oncogenic alterations may best be ascertained using biopsy-based analyses where the effects of ischemia do not complicate interpretation.", "title": "Prostate cancer-associated gene expression alterations determined from needle biopsies." }, { "docid": "27270151", "text": "In the past decade, insightful preclinical research has led to important breakthroughs in our understanding of pancreatic cancer. Even though the vast majority of pancreatic cancers are KRAS mutated, not all pancreatic cancer tumors are \"KRAS equal\"; there seems to be varying dependencies on the KRAS pathway. While KRAS-targeting therapies have been disappointing in the clinic, 'synthetic lethal' approaches hold promise in this setting. The pancreatic cancer stromal microenvironment appears to have contradictory roles. While there is evidence to suggest that stromal barrier prevents drug delivery, in other circumstances, stroma can play a protective role and its disruption enhances tumor dissemination. Clinical trials aimed at manipulating the various stromal components are in progress. BRCA mutation-related pancreatic tumors illustrate a unique subtype with enhanced susceptibility to DNA damaging agents and PARP-inhibition. DNA repair defects in cancer extend beyond germ line BRCA mutation and may extend the indications for DNA repair-targeting agents. Immune strategies are an area of active investigation in pancreatic cancer. Although the initial trials of single-agent checkpoint inhibitors have been negative, combinational approaches using immune-modifying agents and vaccines appear promising and goal is to identify an 'immune-therapy responsive' profile in pancreatic cancer.", "title": "Changing the course of pancreatic cancer--Focus on recent translational advances." }, { "docid": "38243984", "text": "PURPOSE The goal of this study was to evaluate prospectively the engraftment rate, factors influencing engraftment, and predictability of clinical outcome of low-passage xenografts from patients with resectable pancreatic ductal adenocarcinoma (PDA) and to establish a bank of PDA xenografts. EXPERIMENTAL DESIGN Patients with resectable PDA scheduled for resection at the Johns Hopkins Hospital were eligible. Representative pieces of tumor were implanted in nude mice. The status of the SMAD4 gene and content of tumor-generating cells were determined by immunohistochemistry. Gene expression was carried out by using a U133 Plus 2.0 array. Patients were followed for progression and survival. \n RESULTS A total of 94 patients with PDA were resected, 69 tumors implanted in nude mice, and 42 (61%) engrafted. Engrafted carcinomas were more often SMAD4 mutant, and had a metastatic gene expression signature and worse prognosis. Tumors from patients resistant to gemcitabine were enriched in stroma-related gene pathways. Tumors sensitive to gemcitabine were enriched in cell cycle and pyrimidine gene pathways. The time to progression for patients who received treatment with gemcitabine for metastatic disease (n = 7) was double in patients with xenografts sensitive to gemcitabine. \n CONCLUSION A successful xenograft was generated in 61% of patients attempted, generating a pool of 42 PDA xenografts with significant biological information and annotated clinical data. Patients with PDA and SMAD4 inactivation have a better engraftment rate. Engraftment is a poor prognosis factor, and engrafted tumors have a metastatic gene expression signature. Tumors from gemcitabine-resistant patients were enriched in stromal pathways.", "title": "Tumor engraftment in nude mice and enrichment in stroma- related gene pathways predict poor survival and resistance to gemcitabine in patients with pancreatic cancer." } ]

[ { "docid": "712078", "text": "Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (encoded by Cftr) that impair its role as an apical chloride channel that supports bicarbonate transport. Individuals with cystic fibrosis show retained, thickened mucus that plugs airways and obstructs luminal organs as well as numerous other abnormalities that include inflammation of affected organs, alterations in lipid metabolism and insulin resistance. Here we show that colonic epithelial cells and whole lung tissue from Cftr-deficient mice show a defect in peroxisome proliferator-activated receptor-gamma (PPAR-gamma, encoded by Pparg) function that contributes to a pathological program of gene expression. Lipidomic analysis of colonic epithelial cells suggests that this defect results in part from reduced amounts of the endogenous PPAR-gamma ligand 15-keto-prostaglandin E(2) (15-keto-PGE(2)). Treatment of Cftr-deficient mice with the synthetic PPAR-gamma ligand rosiglitazone partially normalizes the altered gene expression pattern associated with Cftr deficiency and reduces disease severity. Rosiglitazone has no effect on chloride secretion in the colon, but it increases expression of the genes encoding carbonic anhydrases 4 and 2 (Car4 and Car2), increases bicarbonate secretion and reduces mucus retention. These studies reveal a reversible defect in PPAR-gamma signaling in Cftr-deficient cells that can be pharmacologically corrected to ameliorate the severity of the cystic fibrosis phenotype in mice.", "title": "Pharmacological correction of a defect in PPARγ signaling ameliorates disease severity in Cftr-deficient mice" } ]

[ { "docid": "20732789", "text": "Cigarette smoke is the main cause of chronic obstructive pulmonary disease (COPD), where it can contribute to the observed airway inflammation. PGE(2) is produced within human airways, and both pro- and anti-inflammatory activities have been reported. We quantitated PGE(2) concentrations in induced sputum supernatants from different groups of subjects and correlated the obtained values to neutrophil infiltration as well as to the expression of cyclooxygenase-2 (COX-2). Cigarette smoke extract (CSE) was used to evaluate the effect of smoking on COX-2 and PGE(2) receptor expression as well as on PGE(2) release in neutrophils and alveolar macrophages (AM) obtained from normal donors. The effects of PGE(2) and of PGE receptor agonists and antagonists were evaluated on the adhesion of neutrophil to a human bronchial epithelial cell line (16HBE). PGE(2) levels, COX-2 expression, and neutrophil infiltration were significantly higher in normal smokers and COPD smokers (P < 0.0001) compared with controls and COPD former smokers. Induced sputum supernatant caused neutrophil adhesion to 16HBE that was significantly reduced, in COPD smokers only, by PGE(2) immunoprecipitation. In vitro experiments confirmed that CSE increased PGE(2) release and COX-2 and PGE(2) receptor expression in neutrophils and AM; PGE(2) enhanced the adhesion of neutrophils to 16HBE, and a specific E-prostanoid 4 (EP(4)) receptor antagonist blunted its effect. These results suggest that CSE promote the induction of COX-2 and contributes to the proinflammatory effects of PGE(2) in the airways of COPD subjects.", "title": "Chronic obstructive pulmonary disease and neutrophil infiltration: role of cigarette smoke and cyclooxygenase products." }, { "docid": "9159125", "text": "Macrophages produce a large amount of PGE(2) during inflammation. This lipid mediator modulates various immune responses. PGE(2) acts on macrophages and inhibits production of cytokines such as TNF-alpha and IL-12. Membrane-bound glutathione-dependent PGE(2) synthase (mPGES) has been shown to be a terminal enzyme of the cyclooxygenase-2-mediated PGE(2) biosynthesis. Here we identified mPGES as a molecule that is induced by LPS in macrophages. The expression of mPGES was not induced by LPS in mice lacking Toll-like receptor 4 or MyD88. Furthermore, mice deficient in NF-IL6 showed neither induction of mPGES nor biosynthesis of PGE(2) in response to LPS, indicating that mPGES expression in response to LPS is regulated by a Toll-like receptor 4/MyD88/NF-IL6-dependent signaling pathway. We generated mPGES-deficient mice and investigated the role of mPGES in vivo. The mice showed no augmentation of the PGE(2) production in response to LPS. However, they were not impaired in the LPS-induced production of inflammatory cytokines and showed normal response to the LPS-induced shock. Thus, mPGES is critically involved in the biosynthesis of PGE(2) induced by LPS, but is dispensable for the modulation of inflammatory responses.", "title": "Lipopolysaccharide-dependent prostaglandin E(2) production is regulated by the glutathione-dependent prostaglandin E(2) synthase gene induced by the Toll-like receptor 4/MyD88/NF-IL6 pathway." }, { "docid": "2443495", "text": "Candida albicans produces lipid metabolites that are functionally similar to host prostaglandins. These studies, using mass spectrometry, demonstrate that C. albicans produces authentic prostaglandin E(2) (PGE(2)) from arachidonic acid. Maximal PGE(2) production was achieved at 37 degrees C in stationary-phase culture supernatants and in cell-free lysates generated from stationary-phase cells. Interestingly, PGE(2) production is inhibited by both nonspecific cyclooxygenase and lipoxygenase inhibitors but not by inhibitors specific for the cyclooxygenase 2 isoenzyme. The C. albicans genome does not possess a cyclooxygenase homolog; however, several genes that may play a role in prostaglandin production from C. albicans were investigated. It was found that a C. albicans fatty acid desaturase homolog (Ole2) and a multicopper oxidase homolog (Fet3) play roles in prostaglandin production, with ole2/ole2 and fet3/fet3 mutant strains exhibiting reduced PGE(2) levels compared with parent strains. This work demonstrates that the synthesis of PGE(2) in C. albicans proceeds via novel pathways.", "title": "Characterization of prostaglandin E2 production by Candida albicans." }, { "docid": "24828165", "text": "Thymic epithelial cells (TEC) form the structural and functional microenvironment necessary for the establishment and quality control of the T cell repertoire. In addition, they provide an ectopic source of numerous tissue-restricted antigens (TRA), a feature called promiscuous gene expression (pGE). How the regulation of pGE is related to the cell biology of TEC subset(s), e.g. their turnover and developmental interrelationship is still poorly understood. The observation that pGE is foremost a property of phenotypically and functionally mature medullary TEC (mTEC) implies that the full implementation of pGE is contingent on mTEC differentiation. Here, we show that the emergence of TEC subsets and pGE is tightly correlated during ontogeny and we provide evidence that mature CD80pos mTEC develop from an immature CD80neg subset. This differentiation step proceeds continuously in the postnatal thymus. While mature mTEC turnover in 2 to 3 weeks, immature mTEC encompass a smaller cycling and a larger non-cycling pool. The latter might serve as a reservoir of committed precursors, which sustain this renewal process. Our data document that mTEC represent a highly dynamic cell population, and they imply that the availability and display of TRA in the thymus undergoes a perpetual temporal and spatial reorganization.", "title": "Promiscuous gene expression and the developmental dynamics of medullary thymic epithelial cells." }, { "docid": "6923961", "text": "Although aberrant DNA methylation is considered to be one of the key ways by which tumor-suppressor and DNA-repair genes are silenced during tumor initiation and progression, the mechanisms underlying DNA methylation alterations in cancer remain unclear. Here we show that prostaglandin E(2) (PGE(2)) silences certain tumor-suppressor and DNA-repair genes through DNA methylation to promote tumor growth. These findings uncover a previously unrecognized role for PGE(2) in the promotion of tumor progression.", "title": "Prostaglandin E2 promotes intestinal tumor growth via DNA methylation" }, { "docid": "343052", "text": "Curcumin, a major component of turmeric, has been shown to exhibit anti-oxidant and anti-inflammatory activities. The present study was performed to determine whether curcumin is efficacious against both collagen-induced arthritis (CIA) in mice and IL-1beta-induced activation in fibroblast-like synoviocytes (FLSs). DBA/1 mice were immunized with bovine type II collagen (CII) and treated with curcumin every other day for 2weeks after the initial immunization. For arthritis, we evaluated the incidence of disease and used an arthritis index based on paw thickness. In vitro proliferation of CII- or concanavalin A-induced splenic T cells was examined using IFN-gamma production. Pro-inflammatory cytokines TNF-alpha and IL-1beta were examined in the mouse ankle joint and serum IgG1 and IgG2a isotypes were analyzed. The expression levels of prostaglandin E(2) (PGE(2)), cyclooxygenase-2 (COX-2), and matrix metalloproteinases (MMPs) in human FLSs were also determined. The results showed that compared with untreated CIA mice, curcumin-treated mice downregulated clinical arthritis score, the proliferation of splenic T cells, expression levels of TNF-alpha and IL-1beta in the ankle joint, and expression levels of IgG2a in serum. Additionally, by altering nuclear factor (NF)-kappaB transcription activity in FLSs, curcumin inhibited PGE(2) production, COX-2 expression, and MMP secretion. These results suggest that curcumin can effectively suppress inflammatory response by inhibiting pro-inflammatory mediators and regulating humoral and cellular immune responses.", "title": "Curcumin attenuates inflammatory response in IL-1beta-induced human synovial fibroblasts and collagen-induced arthritis in mouse model." }, { "docid": "12513042", "text": "The importance of prostaglandin E(2) in various pathophysiological events emphasizes the necessity of understanding the role of PGE synthases (PGESs) in vivo. However, there has been no report on the functional relevance of microsomal PGES-1 (mPGES-1) to the physiological healing processes of gastric ulcers, or to angiogenesis, which is indispensable to the healing processes. In this report, we tested whether mPGES-1 plays a role in the healing of gastric ulcers and in the enhancement of angiogenesis using mPGES-1 knockout mice (mPGES-1 KO mice) and their wild-type (WT) counterparts. Gastric ulcers were induced by the serosal application of 100% acetic acid, and the areas of the ulcers were measured thereafter. mPGES-1 together with cyclooxygenase-2 were induced in the granulation tissues compared with normal stomach tissues. The healing of acetic acid-induced ulcers was significantly delayed in mPGES-1 KO mice compared with WT. This was accompanied with reduced angiogenesis in ulcer granulation tissues, as estimated by CD31 mRNA levels determined by real-time PCR and the microvessel density in granulation tissues. The mRNA levels of proangiogenic growth factors, such as transforming growth factor-β, basic fibroblast growth factor, and connective tissue growth factor in ulcer granulation tissues determined were reduced in mPGES-1 KO mice compared with WT. The present results suggest that mPGES-1 enhances the ulcer-healing processes and the angiogenesis indispensable to ulcer healing, and that a selective mPGES-1 inhibitor should be used with care in patients with gastric ulcers.", "title": "Role of microsomal prostaglandin E synthase-1 in the facilitation of angiogenesis and the healing of gastric ulcers." }, { "docid": "6945691", "text": "Prostaglandins (PGs) have been implicated as a regulator of tumor growth in mice and humans. Since natural killer cell (NK) cytotoxicity may be an important component of immune surveillance against cancer, it is appropriate to study whether the amount of PGs produced by tumors may be sufficient to suppress NK activity. Accordingly, the effect of various PGs on the NK activity of human peripheral mononuclear cells was investigated. The percentage cytotoxicity was measured by the release of Cr51 from labeled K562 and other target cells. At very high concentrations of PG (10(-6) M), suppression was seen with PGE2, PGD2, PGA2, and PGF2 alpha. However, at concentrations of PG in the physiologic range (10(-8) M), significant suppression was seen with PGE2 and PGD2 only. The percentage suppression with PGE2 ranged from 77% to 9.5% over a range of concentrations from 10(-5) to 10(-9) M (45% at 10(-8) M). Significant suppression was observed at 10(-8) M PGE2 with 4 different targets and at effector:target ratios varying from 50:1 to 12.5:1. To assess whether the suppressive effect of PGE2 was directed at the effector and/or target cell, K562 cells or effector cells were pretreated with PGE2. Significant suppression was seen with effector cell pretreatment but not with target cell pretreatment. Finally, the suppressive effects of supernatants obtained from tumor cell lines (polyoma virus-transformed murine fibroblast cell line, PY3T3) was determined. The marked suppressive effect of the supernatant could be attributed to its content of PGE. Thus, it appears that the production of PGE by tumor cells may be an important modulator of human NK activity.", "title": "The modulation of human natural killer cell activity by prostaglandins." }, { "docid": "6280907", "text": "Mesenchymal stem cells can give rise to several cell types, but varying results depending on isolation methods and tissue source have led to controversies about their usefulness in clinical medicine. Here we show that vascular endothelial cells can transform into multipotent stem-like cells by an activin-like kinase-2 (ALK2) receptor–dependent mechanism. In lesions from individuals with fibrodysplasia ossificans progressiva (FOP), a disease in which heterotopic ossification occurs as a result of activating ALK2 mutations, or from transgenic mice expressing constitutively active ALK2, chondrocytes and osteoblasts expressed endothelial markers. Lineage tracing of heterotopic ossification in mice using a Tie2-Cre construct also suggested an endothelial origin of these cell types. Expression of constitutively active ALK2 in endothelial cells caused endothelial-to-mesenchymal transition and acquisition of a stem cell–like phenotype. Similar results were obtained by treatment of untransfected endothelial cells with the ligands transforming growth factor-β2 (TGF-β2) or bone morphogenetic protein-4 (BMP4) in an ALK2-dependent manner. These stem-like cells could be triggered to differentiate into osteoblasts, chondrocytes or adipocytes. We suggest that conversion of endothelial cells to stem-like cells may provide a new approach to tissue engineering.", "title": "Conversion of vascular endothelial cells into multipotent stem-like cells" }, { "docid": "19828689", "text": "Key features of diabetic nephropathy (DN) include the accumulation of extracellular matrix proteins such as collagen 1-alpha 1 and -2 (Col1a1 and -2). Transforming growth factor beta1 (TGF-beta), a key regulator of these extracellular matrix genes, is increased in mesangial cells (MC) in DN. By microarray profiling, we noted that TGF-beta increased Col1a2 mRNA in mouse MC (MMC) but also decreased mRNA levels of an E-box repressor, deltaEF1. TGF-beta treatment or short hairpin RNAs targeting deltaEF1 increased enhancer activity of upstream E-box elements in the Col1a2 gene. TGF-beta also decreased the expression of Smad-interacting protein 1 (SIP1), another E-box repressor similar to deltaEF1. Interestingly, we noted that SIP1 is a target of microRNA-192 (miR-192), a key miR highly expressed in the kidney. miR-192 levels also were increased by TGF-beta in MMC. TGF-beta treatment or transfection with miR-192 decreased endogenous SIP1 expression as well as reporter activity of a SIP1 3' UTR-containing luciferase construct in MMC. Conversely, a miR-192 inhibitor enhanced the luciferase activity, confirming SIP1 to be a miR-192 target. Furthermore, miR-192 synergized with deltaEF1 short hairpin RNAs to increase Col1a2 E-box-luc activity. Importantly, the in vivo relevance was noted by the observation that miR-192 levels were enhanced significantly in glomeruli isolated from streptozotocin-injected diabetic mice as well as diabetic db/db mice relative to corresponding nondiabetic controls, in parallel with increased TGF-beta and Col1a2 levels. These results uncover a role for miRs in the kidney and DN in controlling TGF-beta-induced Col1a2 expression by down-regulating E-box repressors.", "title": "MicroRNA-192 in diabetic kidney glomeruli and its function in TGF-beta-induced collagen expression via inhibition of E-box repressors." }, { "docid": "3127341", "text": "The glucagon-like peptide-1 receptor (GLP-1R) is a key physiological regulator of insulin secretion and a major therapeutic target for the treatment of type II diabetes. However, regulation of GLP-1R function is complex with multiple endogenous peptides that interact with the receptor, including full-length (1-37) and truncated (7-37) forms of GLP-1 that can exist in an amidated form (GLP-1(1-36)NH₂ and GLP-1(7-36)NH₂) and the related peptide oxyntomodulin. In addition, the GLP-1R possesses exogenous agonists, including exendin-4, and the allosteric modulator, compound 2 (6,7-dichloro-2-methylsulfonyl-3-tert-butylaminoquinoxaline). The complexity of this ligand-receptor system is further increased by the presence of several single nucleotide polymorphisms (SNPs) that are distributed across the receptor. We have investigated 10 GLP-1R SNPs, which were characterized in three physiologically relevant signaling pathways (cAMP accumulation, extracellular signal-regulated kinase 1/2 phosphorylation, and intracellular Ca²⁺ mobilization); ligand binding and cell surface receptor expression were also determined. We demonstrate both ligand- and pathway-specific effects for multiple SNPs, with the most dramatic effect observed for the Met¹⁴⁹ receptor variant. At the Met¹⁴⁹ variant, there was selective loss of peptide-induced responses across all pathways examined, but preservation of response to the small molecule compound 2. In contrast, at the Cys³³³ variant, peptide responses were preserved but there was attenuated response to compound 2. Strikingly, the loss of peptide function at the Met¹⁴⁹ receptor variant could be allosterically rescued by compound 2, providing proof-of-principle evidence that allosteric drugs could be used to treat patients with this loss of function variant.", "title": "Polymorphism and ligand dependent changes in human glucagon-like peptide-1 receptor (GLP-1R) function: allosteric rescue of loss of function mutation." }, { "docid": "9680193", "text": "The ubiquitin-binding protein Hrs and endosomal sorting complex required for transport (ESCRT)-I and ESCRT-III are involved in sorting endocytosed and ubiquitinated receptors to lysosomes for degradation and efficient termination of signaling. In this study, we have investigated the role of the ESCRT-II subunit Vps22/EAP30 in degradative protein sorting of ubiquitinated receptors. Vps22 transiently expressed in HeLa cells was detected in endosomes containing endocytosed epidermal growth factor receptors (EGFRs) as well as Hrs and ESCRT-I and ESCRT-III. Depletion of Vps22 by small interfering RNA, which was accompanied by decreased levels of other ESCRT-II subunits, greatly reduced degradation of EGFR and its ligand EGF as well as the chemokine receptor CXCR4. EGFR accumulated on the limiting membranes of early endosomes and aberrantly small multivesicular bodies in Vps22-depleted cells. Phosphorylation and nuclear translocation of extracellular-signal-regulated kinase1/2 downstream of the EGF-activated receptor were sustained by depletion of Hrs or the ESCRT-I subunit Tsg101. In contrast, this was not the case when Vps22 was depleted. These results indicate an important role for Vps22 in ligand-induced EGFR and CXCR4 turnover and suggest that termination of EGF signaling occurs prior to ESCRT-II engagement.", "title": "Vps22/EAP30 in ESCRT-II mediates endosomal sorting of growth factor and chemokine receptors destined for lysosomal degradation." }, { "docid": "6540064", "text": "BACKGROUND Alirocumab, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9), lowers plasma low-density lipoprotein (LDL) cholesterol and apolipoprotein B100 (apoB). Although studies in mice and cells have identified increased hepatic LDL receptors as the basis for LDL lowering by PCSK9 inhibitors, there have been no human studies characterizing the effects of PCSK9 inhibitors on lipoprotein metabolism. In particular, it is not known whether inhibition of PCSK9 has any effects on very low-density lipoprotein or intermediate-density lipoprotein (IDL) metabolism. Inhibition of PCSK9 also results in reductions of plasma lipoprotein (a) levels. The regulation of plasma Lp(a) levels, including the role of LDL receptors in the clearance of Lp(a), is poorly defined, and no mechanistic studies of the Lp(a) lowering by alirocumab in humans have been published to date. \n METHODS Eighteen (10 F, 8 mol/L) participants completed a placebo-controlled, 2-period study. They received 2 doses of placebo, 2 weeks apart, followed by 5 doses of 150 mg of alirocumab, 2 weeks apart. At the end of each period, fractional clearance rates (FCRs) and production rates (PRs) of apoB and apo(a) were determined. In 10 participants, postprandial triglycerides and apoB48 levels were measured. \n RESULTS Alirocumab reduced ultracentrifugally isolated LDL-C by 55.1%, LDL-apoB by 56.3%, and plasma Lp(a) by 18.7%. The fall in LDL-apoB was caused by an 80.4% increase in LDL-apoB FCR and a 23.9% reduction in LDL-apoB PR. The latter was due to a 46.1% increase in IDL-apoB FCR coupled with a 27.2% decrease in conversion of IDL to LDL. The FCR of apo(a) tended to increase (24.6%) without any change in apo(a) PR. Alirocumab had no effects on FCRs or PRs of very low-density lipoproteins-apoB and very low-density lipoproteins triglycerides or on postprandial plasma triglycerides or apoB48 concentrations. \n CONCLUSIONS Alirocumab decreased LDL-C and LDL-apoB by increasing IDL- and LDL-apoB FCRs and decreasing LDL-apoB PR. These results are consistent with increases in LDL receptors available to clear IDL and LDL from blood during PCSK9 inhibition. The increase in apo(a) FCR during alirocumab treatment suggests that increased LDL receptors may also play a role in the reduction of plasma Lp(a). CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01959971.", "title": "Effects of PCSK9 Inhibition With Alirocumab on Lipoprotein Metabolism in Healthy Humans" }, { "docid": "38401028", "text": "1. The changes in the metabolite content in freeze-clamped livers of fed rats occurring on perfusion with 10mm-d-fructose have been examined. 2. The most striking effects of fructose were an accumulation of fructose 1-phosphate, as already known, up to 8.7mumol/g of liver within 10min, a loss of total adenine nucleotides (up to 35% after 40min) with a decrease in the ATP content to 23% within 10min, a sevenfold rise in the concentration of IMP to 1.1mumol/g and an eightfold rise of alpha-glycerophosphate to 1.1mumol/g. 3. There was a transient decrease in P(i) from 4.2 to 1.7mumol/g. Within 40min the P(i) content recovered to the normal value, probably because of an uptake of P(i) from the perfusion medium. 4. The degradation of the adenine nucleotides beyond the stage of AMP can be accounted for by the decrease of ATP and P(i). As ATP inhibits 5-nucleotidase, and as P(i) inhibits AMP deaminase any AMP arising in the tissue is liable to undergo dephosphorylation or deamination under the conditions occurring after fructose loading. 5. The content of lactate increased to 4.3mumol/g at 80min; pyruvate also increased and the [lactate]/[pyruvate] ratio remained within physiological limits. 6. The concentration of free fructose within the liver remained much below that in the perfusion medium, indicating that the rate of penetration of fructose into the tissue was lower than the rate of utilization. 7. The fission of fructose 1-phosphate by liver aldolase is inhibited by several phosphorylated intermediates, especially by IMP. This inhibition is competitive with a K(i) of 0.1mm. 8. The maximal rates of the enzymes synthesizing and splitting fructose 1-phosphate are about equal. The accumulation of fructose 1-phosphate on fructose loading is due to the inhibition of the fission of fructose 1-phosphate by the IMP arising from the degradation of the adenine nucleotides.", "title": "The cause of hepatic accumulation of fructose 1-phosphate on fructose loading." }, { "docid": "52865789", "text": "OBJECTIVE IL-15 is an inflammatory cytokine secreted by many cell types. IL-15 is also produced during physical exercise by skeletal muscle and has been reported to reduce weight gain in mice. Contrarily, our findings on IL-15 knockout (KO) mice indicate that IL-15 promotes obesity. The aim of this study is to investigate the mechanisms underlying the pro-obesity role of IL-15 in adipose tissues. \n METHODS Control and IL-15 KO mice were maintained on high fat diet (HFD) or normal control diet. After 16 weeks, body weight, adipose tissue and skeletal mass, serum lipid levels and gene/protein expression in the adipose tissues were evaluated. The effect of IL-15 on thermogenesis and oxygen consumption was also studied in primary cultures of adipocytes differentiated from mouse preadipocyte and human stem cells. \n RESULTS Our results show that IL-15 deficiency prevents diet-induced weight gain and accumulation of lipids in visceral and subcutaneous white and brown adipose tissues. Gene expression analysis also revealed elevated expression of genes associated with adaptive thermogenesis in the brown and subcutaneous adipose tissues of IL-15 KO mice. Accordingly, oxygen consumption was increased in the brown adipocytes from IL-15 KO mice. In addition, IL-15 KO mice showed decreased expression of pro-inflammatory mediators in their adipose tissues. \n CONCLUSIONS Absence of IL-15 results in decreased accumulation of fat in the white adipose tissues and increased lipid utilization via adaptive thermogenesis. IL-15 also promotes inflammation in adipose tissues that could sustain chronic inflammation leading to obesity-associated metabolic syndrome.", "title": "Deficiency of Interleukin-15 Confers Resistance to Obesity by Diminishing Inflammation and Enhancing the Thermogenic Function of Adipose Tissues" }, { "docid": "52072815", "text": "Summary Background Alcohol use is a leading risk factor for death and disability, but its overall association with health remains complex given the possible protective effects of moderate alcohol consumption on some conditions. With our comprehensive approach to health accounting within the Global Burden of Diseases, Injuries, and Risk Factors Study 2016, we generated improved estimates of alcohol use and alcohol-attributable deaths and disability-adjusted life-years (DALYs) for 195 locations from 1990 to 2016, for both sexes and for 5-year age groups between the ages of 15 years and 95 years and older. Methods Using 694 data sources of individual and population-level alcohol consumption, along with 592 prospective and retrospective studies on the risk of alcohol use, we produced estimates of the prevalence of current drinking, abstention, the distribution of alcohol consumption among current drinkers in standard drinks daily (defined as 10 g of pure ethyl alcohol), and alcohol-attributable deaths and DALYs. We made several methodological improvements compared with previous estimates: first, we adjusted alcohol sales estimates to take into account tourist and unrecorded consumption; second, we did a new meta-analysis of relative risks for 23 health outcomes associated with alcohol use; and third, we developed a new method to quantify the level of alcohol consumption that minimises the overall risk to individual health. Findings Globally, alcohol use was the seventh leading risk factor for both deaths and DALYs in 2016, accounting for 2·2% (95% uncertainty interval [UI] 1·5–3·0) of age-standardised female deaths and 6·8% (5·8–8·0) of age-standardised male deaths. Among the population aged 15–49 years, alcohol use was the leading risk factor globally in 2016, with 3·8% (95% UI 3·2–4·3) of female deaths and 12·2% (10·8–13·6) of male deaths attributable to alcohol use. For the population aged 15–49 years, female attributable DALYs were 2·3% (95% UI 2·0–2·6) and male attributable DALYs were 8·9% (7·8–9·9). The three leading causes of attributable deaths in this age group were tuberculosis (1·4% [95% UI 1·0–1·7] of total deaths), road injuries (1·2% [0·7–1·9]), and self-harm (1·1% [0·6–1·5]). For populations aged 50 years and older, cancers accounted for a large proportion of total alcohol-attributable deaths in 2016, constituting 27·1% (95% UI 21·2–33·3) of total alcohol-attributable female deaths and 18·9% (15·3–22·6) of male deaths. The level of alcohol consumption that minimised harm across health outcomes was zero (95% UI 0·0–0·8) standard drinks per week. Interpretation Alcohol use is a leading risk factor for global disease burden and causes substantial health loss. We found that the risk of all-cause mortality, and of cancers specifically, rises with increasing levels of consumption, and the level of consumption that minimises health loss is zero. These results suggest that alcohol control policies might need to be revised worldwide, refocusing on efforts to lower overall population-level consumption. Funding Bill & Melinda Gates Foundation.", "title": "Alcohol use and burden for 195 countries and territories, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016" }, { "docid": "18038250", "text": "Within the developing mammalian CNS, growth factors direct multipotent precursors to generate neurons versus glia, a process that if perturbed might lead to neural dysfunction. In this regard, genetic mutations resulting in constitutive activation of the protein tyrosine phosphatase SHP-2 cause Noonan Syndrome (NS), which is associated with learning disabilities and mental retardation. Here, we demonstrate that genetic knockdown of SHP-2 in cultured cortical precursors or in the embryonic cortex inhibited basal neurogenesis and caused enhanced and precocious astrocyte formation. Conversely, expression of an NS SHP-2 mutant promoted neurogenesis and inhibited astrogenesis. Neural cell-fate decisions were similarly perturbed in a mouse knockin model that phenocopies human NS. Thus, SHP-2 instructs precursors to make neurons and not astrocytes during the neurogenic period, and perturbations in the relative ratios of these two cell types upon constitutive SHP-2 activation may contribute to the cognitive impairments in NS patients.", "title": "Control of CNS Cell-Fate Decisions by SHP-2 and Its Dysregulation in Noonan Syndrome" }, { "docid": "883747", "text": "Group 2 innate lymphoid cells (ILC2s) secrete type 2 cytokines, which protect against parasites but can also contribute to a variety of inflammatory airway diseases. We report here that interleukin 1β (IL-1β) directly activated human ILC2s and that IL-12 induced the conversion of these activated ILC2s into interferon-γ (IFN-γ)-producing ILC1s, which was reversed by IL-4. The plasticity of ILCs was manifested in diseased tissues of patients with severe chronic obstructive pulmonary disease (COPD) or chronic rhinosinusitis with nasal polyps (CRSwNP), which displayed IL-12 or IL-4 signatures and the accumulation of ILC1s or ILC2s, respectively. Eosinophils were a major cellular source of IL-4, which revealed cross-talk between IL-5-producing ILC2s and IL-4-producing eosinophils. We propose that IL-12 and IL-4 govern ILC2 functional identity and that their imbalance results in the perpetuation of type 1 or type 2 inflammation.", "title": "IL-1β, IL-4 and IL-12 control the fate of group 2 innate lymphoid cells in human airway inflammation in the lungs" }, { "docid": "13573143", "text": "Comparative Gene Identification-58 (CGI-58), a lipid droplet (LD)-associated protein, promotes intracellular triglyceride (TG) hydrolysis in vitro. Mutations in human CGI-58 cause TG accumulation in numerous tissues including intestine. Enterocytes are thought not to store TG-rich LDs, but a fatty meal does induce temporary cytosolic accumulation of LDs. Accumulated LDs are eventually cleared out, implying existence of TG hydrolytic machinery in enterocytes. However, identities of proteins responsible for LD-TG hydrolysis remain unknown. Here we report that intestine-specific inactivation of CGI-58 in mice significantly reduces postprandial plasma TG concentrations and intestinal TG hydrolase activity, which is associated with a 4-fold increase in intestinal TG content and large cytosolic LD accumulation in absorptive enterocytes during the fasting state. Intestine-specific CGI-58 knockout mice also display mild yet significant decreases in intestinal fatty acid absorption and oxidation. Surprisingly, inactivation of CGI-58 in intestine significantly raises plasma and intestinal cholesterol, and reduces hepatic cholesterol, without altering intestinal cholesterol absorption and fecal neutral sterol excretion. In conclusion, intestinal CGI-58 is required for efficient postprandial lipoprotein-TG secretion and for maintaining hepatic and plasma lipid homeostasis. Our animal model will serve as a valuable tool to further define how intestinal fat metabolism influences the pathogenesis of metabolic disorders, such as obesity and type 2 diabetes.", "title": "Intestinal Cgi-58 Deficiency Reduces Postprandial Lipid Absorption" } ]

[ { "docid": "4506414", "text": "BACKGROUND The associations of blood pressure with the different manifestations of incident cardiovascular disease in a contemporary population have not been compared. In this study, we aimed to analyse the associations of blood pressure with 12 different presentations of cardiovascular disease. \n METHODS We used linked electronic health records from 1997 to 2010 in the CALIBER (CArdiovascular research using LInked Bespoke studies and Electronic health Records) programme to assemble a cohort of 1·25 million patients, 30 years of age or older and initially free from cardiovascular disease, a fifth of whom received blood pressure-lowering treatments. We studied the heterogeneity in the age-specific associations of clinically measured blood pressure with 12 acute and chronic cardiovascular diseases, and estimated the lifetime risks (up to 95 years of age) and cardiovascular disease-free life-years lost adjusted for other risk factors at index ages 30, 60, and 80 years. This study is registered at ClinicalTrials.gov, number NCT01164371. \n FINDINGS During 5·2 years median follow-up, we recorded 83,098 initial cardiovascular disease presentations. In each age group, the lowest risk for cardiovascular disease was in people with systolic blood pressure of 90-114 mm Hg and diastolic blood pressure of 60-74 mm Hg, with no evidence of a J-shaped increased risk at lower blood pressures. The effect of high blood pressure varied by cardiovascular disease endpoint, from strongly positive to no effect. Associations with high systolic blood pressure were strongest for intracerebral haemorrhage (hazard ratio 1·44 [95% CI 1·32-1·58]), subarachnoid haemorrhage (1·43 [1·25-1·63]), and stable angina (1·41 [1·36-1·46]), and weakest for abdominal aortic aneurysm (1·08 [1·00-1·17]). Compared with diastolic blood pressure, raised systolic blood pressure had a greater effect on angina, myocardial infarction, and peripheral arterial disease, whereas raised diastolic blood pressure had a greater effect on abdominal aortic aneurysm than did raised systolic pressure. Pulse pressure associations were inverse for abdominal aortic aneurysm (HR per 10 mm Hg 0·91 [95% CI 0·86-0·98]) and strongest for peripheral arterial disease (1·23 [1·20-1·27]). People with hypertension (blood pressure ≥140/90 mm Hg or those receiving blood pressure-lowering drugs) had a lifetime risk of overall cardiovascular disease at 30 years of age of 63·3% (95% CI 62·9-63·8) compared with 46·1% (45·5-46·8) for those with normal blood pressure, and developed cardiovascular disease 5·0 years earlier (95% CI 4·8-5·2). Stable and unstable angina accounted for most (43%) of the cardiovascular disease-free years of life lost associated with hypertension from index age 30 years, whereas heart failure and stable angina accounted for the largest proportion (19% each) of years of life lost from index age 80 years. \n INTERPRETATION The widely held assumptions that blood pressure has strong associations with the occurrence of all cardiovascular diseases across a wide age range, and that diastolic and systolic associations are concordant, are not supported by the findings of this high-resolution study. Despite modern treatments, the lifetime burden of hypertension is substantial. These findings emphasise the need for new blood pressure-lowering strategies, and will help to inform the design of randomised trials to assess them. \n FUNDING Medical Research Council, National Institute for Health Research, and Wellcome Trust.", "title": "Blood pressure and incidence of twelve cardiovascular diseases: lifetime risks, healthy life-years lost, and age-specific associations in 1·25 million people" } ]

[ { "docid": "12549585", "text": "Pulse wave velocity (PWV) was measured in the aorta, right leg and arm of 90 control subjects (CS) and 92 hemodialysis patients (HD) of the same age and mean arterial pressure (MAP). Blood chemistry, including blood lipids, and echographic dimensions of the aorta, were measured in all subjects. Presence of aortic calcification was evaluated by abdominal X-ray and echography. Whereas femoral and brachial PWV were only slightly increased in HD (P less than 0.05), the aortic PWV was significantly elevated (1113 +/- 319 cm/sec) in comparison with CS (965 +/- 216 cm/sec; P = 0.0016). Aortic diameters were larger in HD, both at the root of aorta (32.7 +/- 4 vs. 28.2 +/- 2.8 mm; P less than 0.0001) and aortic bifurcation (16.9 +/- 3.1 vs. 14.6 +/- 2.2 mm; P less than 0.0001). Although the MAP was similar in HD (109.9 +/- 19.3 mm Hg) and CS (110.2 +/- 17.2 mm Hg), the pulse pressure was significantly increased in HD patients (76.6 +/- 23.7 vs. 63.9 +/- 22 mm Hg; P = 0.007). In the two populations, aortic PWV was found to increase with age (P less than 0.0001) and MAP (P less than 0.0001). The presence of aortic calcification showed only a borderline relationship with the increase in aortic PWV (P = 0.050 in CS and P = 0.069 in HD). As change in PWV is directly related to change in distensibility, and the aortic diameters were increased in HD, these results indicate that aortic wall compliance is decreased in HD, resulting in an increase in the pulsatile component of arterial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)", "title": "Aortic and large artery compliance in end-stage renal failure." }, { "docid": "30058568", "text": "CONTEXT Managing thoracic aortic aneurysms identified incidentally by increased use of computed tomography, echocardiography, and magnetic resonance imaging is problematic, especially in the elderly. \n OBJECTIVE To ascertain whether the previously reported poor prognosis for individuals with thoracic aortic aneurysms has changed with better medical therapies and improved surgical techniques that can now be applied to aneurysm management. \n DESIGN Population-based cohort study. \n SETTING AND PATIENTS All 133 patients with the diagnosis of degenerative thoracic aortic aneurysms among Olmsted County, Minnesota, residents between 1980 and 1994 compared with a previously reported cohort of similar patients between 1951 and 1980. \n MAIN OUTCOME MEASURES The primary clinical end points were incidence, cumulative rupture risk, rupture risk as a function of aneurysm size, and survival. \n RESULTS In contrast to abdominal aortic aneurysms, for which men are affected predominately, 51% of thoracic aortic aneurysms were identified in women who were considerably older at recognition than men (mean age, 75.9 vs 62.8 years, respectively; P= .01). The overall incidence rate of 10.4 per 100000 person-years (95% confidence interval [CI], 8.6-12.2) between 1980 and 1994 was more than 3-fold higher than the rate from 1951 to 1980. The cumulative risk of rupture was 20% after 5 years. Seventy-nine percent of ruptures occurred in women (P= .01). The 5-year risk of rupture as a function of aneurysm size at recognition was 0% for aneurysms less than 4 cm in diameter, 16% (95% CI, 4%-28%) for those 4 to 5.9 cm, and 31% (95% CI, 5%-56%) for aneurysms 6 cm or more. Overall 5-year survival improved to 56% (95% CI, 48%-66%) between 1980 and 1994 compared with only 19% between 1951 and 1980 (P<.01). \n CONCLUSIONS In this population, elderly women represent an increasing portion of all patients with clinically recognized thoracic aortic aneurysms and constitute the majority of patients whose aneurysm eventually ruptures. Overall survival for thoracic aortic aneurysms has improved significantly in the past 15 years.", "title": "Improved prognosis of thoracic aortic aneurysms: a population-based study." }, { "docid": "30639847", "text": "CONTEXT Vascular stiffness increases with advancing age and is a major risk factor for age-related morbidity and mortality. Vascular stiffness and blood pressure pulsatility are related; however, temporal relationships between vascular stiffening and blood pressure elevation have not been fully delineated. \n OBJECTIVE To examine temporal relationships among vascular stiffness, central hemodynamics, microvascular function, and blood pressure progression. \n DESIGN, SETTING, AND PARTICIPANTS Longitudinal community-based cohort study conducted in Framingham, Massachusetts. The present investigation is based on the 2 latest examination cycles (cycle 7: 1998-2001; cycle 8: 2005-2008 [last visit: January 25, 2008]) of the Framingham Offspring study (recruited: 1971-1975). Temporal relationships among blood pressure and 3 measures of vascular stiffness and pressure pulsatility derived from arterial tonometry (carotid-femoral pulse wave velocity [CFPWV], forward wave amplitude [FWA], and augmentation index) were examined over a 7-year period in 1759 participants (mean [SD] age: 60 [9] years; 974 women). \n MAIN OUTCOME MEASURES The primary outcomes were blood pressure and incident hypertension during examination cycle 8. The secondary outcomes were CFPWV, FWA, and augmentation index during examination cycle 8. \n RESULTS In a multivariable-adjusted regression model, higher FWA (β, 1.3 [95% CI, 0.5-2.1] mm Hg per 1 SD; P = .002) and higher CFPWV (β, 1.5 [95% CI, 0.5-2.6] mm Hg per 1 SD; P = .006) during examination cycle 7 were jointly associated with systolic blood pressure during examination cycle 8. Similarly, in a model that included systolic and diastolic blood pressure and additional risk factors during examination cycle 7, higher FWA (odds ratio [OR], 1.6 [95% CI, 1.3-2.0] per 1 SD; P < .001), augmentation index (OR, 1.7 [95% CI, 1.4-2.0] per 1 SD; P < .001), and CFPWV (OR, 1.3 [95% CI, 1.0-1.6] per 1 SD; P = .04) were associated with incident hypertension during examination cycle 8 (338 cases [32%] in 1048 participants without hypertension during examination cycle 7). Conversely, blood pressure during examination cycle 7 was not associated with CFPWV during examination cycle 8. Higher resting brachial artery flow (OR, 1.23 [95% CI, 1.04-1.46]) and lower flow-mediated dilation (OR, 0.80 [95% CI, 0.67-0.96]) during examination cycle 7 were associated with incident hypertension (in models that included blood pressure and tonometry measures collected during examination cycle 7). \n CONCLUSION In this cohort, higher aortic stiffness, FWA, and augmentation index were associated with higher risk of incident hypertension; however, initial blood pressure was not independently associated with risk of progressive aortic stiffening.", "title": "Aortic stiffness, blood pressure progression, and incident hypertension." }, { "docid": "4890578", "text": "Time for primary reveiw 27 days Atherosclerosis continues to be one of the main subjects in pathology research. The intriguing complexity of its pathogenesis as well as the importance of its clinical sequelae provide a rationale for this [1]. A large number of diseases with totally different clinical presentations are basically atherosclerosis related, and among these, myocardial infarction, stroke, abdominal aneurysms and lower limb ischemia determine to a large extent the morbidity and mortality in Western style populations. But, despite this broad spectrum of clinical disease, most of the acute manifestations of atherosclerosis share a common pathogenetic feature: rupture of an atherosclerotic plaque [2–4]. Plaque disruptions may vary greatly in extent from tiny fissures or erosions of the plaque surface to deep intimal tears which extend into the soft lipid core of lesions; in all these instances, at least some degree of thrombus formation occurs [5, 6]. The abdominal aorta is the arterial site most prominently involved in the process of plaque formation, and also of plaque complications. In this large diameter vessel the process of plaque disruption and thrombosis is not ended by luminal occlusion, and may lead to extensive surface ulcerations comprising large areas of the aortic wall, as can be observed in many autopsy cases at older age. Apart from the undisputable role of atherosclerosis in abdominal aneurysm formation [7], mural thrombosis leads to a surprisingly low rate of clinically significant complications in these patients, although cholesterol emboli can be regularly found in their kidneys and skin at autopsy. Still, it is presently unclear what impact the various biologically active mediators released from eroded aortic surfaces may have on the human body. In contrast, in small diameter vessels such as coronary arteries, occlusive thrombosis is a frequent and often fatal complication of plaque … * Corresponding author. Tel.: +31-20-5665-633; fax: +31-20-914-738; e-mail a.c.vanderwal@amc.uva.nl", "title": "Atherosclerotic plaque rupture--pathologic basis of plaque stability and instability." }, { "docid": "18997216", "text": "Muscle sympathetic nerve activity is increased during normotensive pregnancy while mean arterial pressure is maintained or reduced, suggesting baroreflex resetting. We hypothesized spontaneous sympathetic baroreflex gain would be reduced in normotensive pregnant women relative to nonpregnant matched controls. Integrated muscle sympathetic burst incidence and total sympathetic activity (microneurography), blood pressure (Finometer), and R-R interval (ECG) were assessed at rest in 11 pregnant women (33 ± 1 wk gestation, 31 ± 1 yr, prepregnancy BMI: 23.5 ± 0.9 kg/m(2)) and 11 nonpregnant controls (29 ± 1 yr; BMI: 25.2 ± 1.7 kg/m(2)). Pregnant women had elevated baseline sympathetic burst incidence (43 ± 2 vs. 33 ± 2 bursts/100 heart beats, P = 0.01) and total sympathetic activity (1,811 ± 148 vs. 1,140 ± 55 au, P < 0.01) relative to controls. Both mean (88 ± 3 vs. 91 ± 2 mmHg, P = 0.4) and diastolic (DBP) (72 ± 3 vs. 73 ± 2 mmHg, P = 0.7) pressures were similar between pregnant and nonpregnant women, respectively, indicating an upward resetting of the baroreflex set point with pregnancy. Baroreflex gain, calculated as the linear relationship between sympathetic burst incidence and DBP, was reduced in pregnant women relative to controls (-3.7 ± 0.5 vs. -5.4 ± 0.5 bursts·100 heart beats(-1)·mmHg(-1), P = 0.03), as was baroreflex gain calculated with total sympathetic activity (-294 ± 24 vs. -210 ± 24 au·100 heart beats(-1)·mmHg(-1); P = 0.03). Cardiovagal baroreflex gain (sequence method) was not different between nonpregnant controls and pregnant women (49 ± 8 vs. 36 ± 8 ms/mmHg; P = 0.2). However, sympathetic (burst incidence) and cardiovagal gains were negatively correlated in pregnant women (R = -0.7; P = 0.02). Together, these data indicate that the influence of the sympathetic nervous system over arterial blood pressure is reduced in normotensive pregnancy, in terms of both long-term and beat-to-beat regulation of arterial pressure, likely through a baroreceptor-dependent mechanism.", "title": "Sympathetic baroreflex gain in normotensive pregnant women." }, { "docid": "8596837", "text": "Women with a history of hypertensive pregnancy are at greater risk for future cardiovascular events; however, the mechanisms for this increased risk are unknown. Evidence suggests that an exercise stimulus unmasks latent hypertensive tendencies, identifying individuals at the greatest risk for developing cardiovascular disease. The current study examined the hypothesis that women with a hypertensive pregnancy history exhibit an augmented exercise pressor response. Normotensive women with a history of healthy pregnancy (CON; n = 9) and hypertensive pregnancy (HP+; n = 12) were studied during the mid-luteal phase of the menstrual cycle. Heart rate (HR), systolic and diastolic blood pressure (SBP, DBP), and muscle sympathetic nerve activity (MSNA) were measured during a cold pressor test (CPT), and, following a sufficient period of recovery, during static handgrip to fatigue (SHG) and post-exercise circulatory arrest (PECA). The BP, HR, and MSNA responses to the CPT were similar between groups. The SBP response to SHG and PECA was similar between groups, but DBP and HR were significantly greater in HP+ women (both p < 0.05). MSNA burst frequency, but not burst incidence or total activity, tended to be elevated in HP+ women during the stressor (peak Δ from baseline 31 ± 13 vs. 23 ± 13 bursts/min; p for group = 0.06). Despite no clinical signs of cardiovascular disease or hypertension, women with a history of hypertensive pregnancy display an enhanced cardiovascular reactivity to an exercise stimulus compared to women with a healthy pregnancy history. This response may be indicative of impaired cardiovascular control that precedes the clinical manifestation of hypertension or cardiovascular events.", "title": "Sympathetic neural and cardiovascular responses during static handgrip exercise in women with a history of hypertensive pregnancy" }, { "docid": "6525844", "text": "BACKGROUND Damage to large arteries is a major factor in the high cardiovascular morbidity and mortality of patients with end-stage renal disease (ESRD). Increased arterial stiffness and intima-media thickness, together with increased pulse pressure, are the principal arterial alterations. Whether increased aortic pulse-wave velocity (PWV), a classic marker of increased arterial stiffness, may predict all-cause and/or cardiovascular mortality has never been investigated. \n METHODS AND RESULTS A cohort of 241 patients with ESRD undergoing hemodialysis was studied between April 1987 and April 1998. The mean duration of follow-up was 72+/-41 months (mean+/-SD). Mean age at entry was 51.5+/-16.3 years. Seventy-three deaths occurred, including 48 cardiovascular and 25 noncardiovascular fatal events. At entry, together with standard clinical and biochemical analyses, patients underwent echocardiography and aortic PWV measured by Doppler ultrasonography. On the basis of Cox analyses, 2 factors emerged as predictors of all-cause and cardiovascular mortality: age and aortic PWV. Hemoglobin and low diastolic pressure interfered to a smaller extent. After adjustment for all the confounding factors, an OR for PWV >12. 0 versus <9.4 m/s was 5.4 (95% CI, 2.4 to 11.9) for all-cause mortality and 5.9 (95% CI, 2.3 to 15.5) for cardiovascular mortality. For each PWV increase of 1 m/s in our study population, all-cause mortality-adjusted OR was 1.39 (95% CI, 1.19 to 1.62). \n CONCLUSIONS These results provide the first direct evidence that in patients with ESRD, increased aortic stiffness determined by measurement of aortic PWV is a strong independent predictor of all-cause and mainly cardiovascular mortality.", "title": "Impact of aortic stiffness on survival in end-stage renal disease." }, { "docid": "12513972", "text": "BACKGROUND Intracranial aneurysm (IA) is significantly more prevalent in patients with coarctation of the aorta or bicuspid aortic valve than in the general population, suggesting a common pathophysiology connecting IA and aortopathy. Here, we analyzed echocardiographic aortic root dimension (ARD) in patients with IA to confirm this possibility. \n METHODS From January 2008 to December 2010, 260 consecutive patients with IA who were admitted to our institution for coil embolization or for acute stroke management and who also underwent echocardiography were enrolled. We hypothesized that patients with large, ruptured, or multiple IAs are more likely to harbor co-prevalent aortopathy as measured by ARD compared to patients with small, isolated, unruptured IAs. Eccentric group was defined as patients aged <55 years with at least one ruptured aneurysm, an aneurysm ≥7 mm in size, or multiple aneurysms; the remainder was classified into a non-eccentric group. Clinical, angiographic, and echocardiographic findings of the two groups were compared. \n RESULTS ARD was significantly larger in the eccentric group than in the non-eccentric group (P = 0.049), and the difference was confirmed by multivariable analysis (P = 0.02). Subgroup analysis of patients aged <55 years showed similar result for ARD (P = 0.03), whereas hypertension was more associated with the non-eccentric group (P = 0.01). In addition, height was inversely related to aneurysm size after adjustment for age, sex, weight, ARD, smoking status, and number of aneurysms (P = 0.004). \n CONCLUSIONS A certain group of IA patients share a common intrinsic wall defect with aortopathy. Shared neural crest cell origin may give rise to this phenomenon.", "title": "Echocardiographic Evidence of Innate Aortopathy in the Human Intracranial Aneurysm" }, { "docid": "22730024", "text": "OBJECTIVE To assess the antihypertensive efficacy of olmesartan medoxomil and ramipril on 24-h ambulatory blood pressure (ABP) in elderly hypertensive patients by pooled data analysis of two studies with identical designs (one Italian, one European). \n METHODS After a 2-week placebo wash-out 1453 elderly hypertensive patients (65-89 years; sitting office DBP 90-109 mmHg and/or sitting office SBP 140-179 mmHg) were randomized to a 12-week double-blind treatment with olmesartan medoxomil 10 mg or ramipril 2.5 mg once-daily, up-titrated (20 and 40 mg olmesartan medoxomil; 5 and 10 mg ramipril) after 2 and 6 weeks in patients without normalized office BP. 24-h ABP was recorded at randomization and after 12 weeks. \n RESULTS In 715 patients with valid baseline and end-of-treatment recordings baseline-adjusted 24-h SBP and DBP reductions were greater with olmesartan medoxomil (n = 356) than with ramipril (n = 359) [between-treatment differences and 95% confidence interval (CI), SBP: 2.2 (3.8, 0.6), P = 0.006; DBP: 1.3 (2.2, 0.3), P = 0.009]. Olmesartan medoxomil showed larger BP reductions in the last 6 h from the dosing interval and higher smoothness indices than ramipril. Olmesartan medoxomil reduced the SBP morning rise [-2.8 (-4.9, -0.8) mmHg], whereas ramipril did not [+1.5 (-0.6, +3.6) mmHg; P = 0.004 between-treatments]. Five hundred and eighty-two patients with sustained hypertension (office and 24-h ambulatory hypertension) showed the largest antihypertensive effect, with between-treatment differences still in favor of olmesartan medoxomil [SBP: 2.1 (3.9, 0.4), P = 0.019; DBP: 1.2 (2.3, 0.1), P = 0.032]. \n CONCLUSIONS Olmesartan medoxomil provides a more effective and sustained 24-h BP control than ramipril in elderly hypertensive patients, particularly in the hours farthest from last intake.", "title": "Twenty-four hour and early morning blood pressure control of olmesartan vs. ramipril in elderly hypertensive patients: pooled individual data analysis of two randomized, double-blind, parallel-group studies." }, { "docid": "19804204", "text": "BACKGROUND AND OBJECTIVES Children with chronic kidney disease (CKD) are at risk for cognitive dysfunction, and over half have hypertension. Data on the potential contribution of hypertension to CKD-associated neurocognitive deficits in children are limited. Our objective was to determine whether children with CKD and elevated BP (EBP) had decreased performance on neurocognitive testing compared with children with CKD and normal BP. \n DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This was a cross-sectional analysis of the relation between auscultatory BP and neurocognitive test performance in children 6 to 17 years enrolled in the Chronic Kidney Disease in Children (CKiD) project. \n RESULTS Of 383 subjects, 132 (34%) had EBP (systolic BP and/or diastolic BP ≥90(th) percentile). Subjects with EBP had lower mean (SD) scores on Wechsler Abbreviated Scales of Intelligence (WASI) Performance IQ than those with normal BP (normal BP versus EBP, 96.1 (16.7) versus 92.4 (14.9), P = 0.03) and WASI Full Scale IQ (97.0 (16.2) versus 93.4 (16.5), P = 0.04). BP index (subject's BP/95(th) percentile BP) correlated inversely with Performance IQ score (systolic, r = -0.13, P = 0.01; diastolic, r = -0.19, P < 0.001). On multivariate analysis, the association between lower Performance IQ score and increased BP remained significant after controlling for demographic and disease-related variables (EBP, β = -3.7, 95% confidence interval [CI]: -7.3 to -0.06; systolic BP index, β = -1.16 to 95% CI: -2.1, -0.21; diastolic BP index, β = -1.17, 95% CI: -1.8 to -0.55). \n CONCLUSIONS Higher BP was independently associated with decreased WASI Performance IQ scores in children with mild-to-moderate CKD.", "title": "Casual blood pressure and neurocognitive function in children with chronic kidney disease: a report of the children with chronic kidney disease cohort study." }, { "docid": "202259", "text": "BACKGROUND Patients undergoing dialysis have a substantially increased risk of cardiovascular mortality and morbidity. Although several trials have shown the cardiovascular benefits of lowering blood pressure in the general population, there is uncertainty about the efficacy and tolerability of reducing blood pressure in patients on dialysis. We did a systematic review and meta-analysis to assess the effect of blood pressure lowering in patients on dialysis. \n METHODS We systematically searched Medline, Embase, and the Cochrane Library database for trials reported between 1950 and November, 2008, without language restriction. We extracted a standardised dataset from randomised controlled trials of blood pressure lowering in patients on dialysis that reported cardiovascular outcomes. Meta-analysis was done with a random effects model. \n FINDINGS We identified eight relevant trials, which provided data for 1679 patients and 495 cardiovascular events. Weighted mean systolic blood pressure was 4.5 mm Hg lower and diastolic blood pressure 2.3 mm Hg lower in actively treated patients than in controls. Blood pressure lowering treatment was associated with lower risks of cardiovascular events (RR 0.71, 95% CI 0.55-0.92; p=0.009), all-cause mortality (RR 0.80, 0.66-0.96; p=0.014), and cardiovascular mortality (RR 0.71, 0.50-0.99; p=0.044) than control regimens. The effects seem to be consistent across a range of patient groups included in the studies. \n INTERPRETATION Treatment with agents that lower blood pressure should routinely be considered for individuals undergoing dialysis to reduce the very high cardiovascular morbidity and mortality rate in this population.", "title": "Effect of lowering blood pressure on cardiovascular events and mortality in patients on dialysis: a systematic review and meta-analysis of randomised controlled trials" }, { "docid": "13108582", "text": "Osteopontin (OPN), a key component of the extracellular matrix, is associated with the fibrotic process during tissue remodeling. OPN and the cytokine interleukin (IL)-18 have been shown to be overexpressed in an array of human cardiac pathologies. In the present study, we determined the role of IL-18 in the regulation of cardiac OPN expression and the subsequent interstitial fibrosis and diastolic dysfunction. We demonstrated parallel increases in IL-18, OPN expression, and interstitial fibrosis in murine models of left ventricular pressure and volume overload. Exogenous recombinant (r)IL-18 administered for 2 wk increased cardiac OPN expression, interstitial fibrosis, and diastolic dysfunction. Stimulation of the T helper (Th)1 lymphocyte phenotype with a selective toll-like receptor (TLR)9 agonist induced cardiac IL-18 and OPN expression, which was associated with increased cardiac fibrillar collagen concentrations and interstitial fibrosis resulting in diastolic dysfunction. rIL-18 induced OPN expression and protein levels in primary of cardiac fibroblast cultures. Conditioned media from TLR9-stimulated T lymphocyte cultures induced IL-18 and OPN expression in cardiac fibroblasts, while blockade of the IL-18 receptor with a neutralizing antibody abolished the increase in OPN expression. Furthermore, a mutation in the transcriptional factor interferon regulatory factor (IRF)1 or IRF1 small interfering RNA (siRNA) resulted in the decreased expression of IL-18 and OPN in cardiac fibroblasts. With pressure overload, IRF1-mutant mice showed downregulation of IL-18 and OPN expression in cardiac tissue, reduced cardiac fibrotic development, and increased left ventricular function compared with wild type. These results provide direct evidence that the induction of IL-18 regulates OPN-mediated cardiac fibrosis and diastolic dysfunction.", "title": "IL-18 induction of osteopontin mediates cardiac fibrosis and diastolic dysfunction in mice." }, { "docid": "26710772", "text": "Sympathetic activity has been reported to increase in normotensive pregnant women, and to be even greater in women with gestational hypertension and preeclampsia at term. Whether sympathetic overactivity develops early during pregnancy, remaining high throughout gestation, or whether it only occurs at term providing the substrate for hypertensive disorders is unknown. We tested the hypothesis that sympathetic activation occurs early during pregnancy in humans. Eleven healthy women (29 ± 3 (SD) years) without prior hypertensive pregnancies were tested during the mid-luteal phase (PRE) and early pregnancy (EARLY; 6.2 ± 1.2 weeks of gestation). Muscle sympathetic nerve activity (MSNA) and haemodynamics were measured supine, at 30 deg and 60 deg upright tilt for 5 min each. Blood samples were drawn for catecholamines, direct renin, and aldosterone. MSNA was significantly greater during EARLY than PRE (supine: 25 ± 8 vs. 14 ± 8 bursts min(-1), 60 deg tilt: 49 ± 14 vs. 40 ± 10 bursts min(-1); main effect, P < 0.05). Resting diastolic pressure trended lower (P = 0.09), heart rate was similar, total peripheral resistance decreased (2172 ± 364 vs. 2543 ± 352 dyne s cm(-5); P < 0.05), sympathetic vascular transduction was blunted (0.10 ± 0.05 vs. 0.36 ± 0.47 units a.u.(-1) min(-1); P < 0.01), and both renin (supine: 27.9 ± 6.2 vs. 14.2 ± 8.7 pg ml(-1), P < 0.01) and aldosterone (supine: 16.7 ± 14.1 vs. 7.7 ± 6.8 ng ml(-1), P = 0.05) were higher during EARLY than PRE. These results suggest that sympathetic activation is a common characteristic of early pregnancy in humans despite reduced diastolic pressure and total peripheral resistance. These observations challenge conventional thinking about blood pressure regulation during pregnancy, showing marked sympathetic activation occurring within the first few weeks of conception, and may provide the substrate for pregnancy induced cardiovascular complications.", "title": "Sympathetic activation during early pregnancy in humans." }, { "docid": "24998764", "text": "Chronic kidney disease is accompanied by increased large-artery stiffness, but the relation between glomerular filtration rate within the reference range and central or peripheral arterial stiffness has been understudied. The link between renal function and arterial stiffness was assessed in 305 patients with never-treated essential hypertension (men: 58%; age: 48+/-11 years, blood pressure: 151/95+/-20/11 mm Hg), free from overt cardiovascular disease and with serum creatinine values <1.4 mg/dL (men) and <1.2 mg/dL (women), who underwent noninvasive aortic and upper-limb pulse wave velocity (PWV) determination. Aortic PWV was strongly related to age (r=0.55; P<0.001), whereas upper-limb PWV had a weaker nonlinear relation with age (beta=1.392; P<0.001 for age; beta=-1.312; P<0.001 for age squared) and a weak relation with aortic PWV (r=0.22; P<0.001). Glomerular filtration rate (GFR), estimated according to the Mayo clinic equation for healthy subjects, was inversely correlated with large-artery stiffness, as assessed by aortic PWV (r=-0.34; P<0.001), and with peripheral artery stiffness, as assessed by upper-limb PWV (r=-0.25; P<0.001). In a multivariate linear regression, aortic PWV was independently predicted by age (beta=0.48; P<0.001), mean arterial pressure (beta=0.14; P=0.013), and GFR (beta=-0.13, P=0.029). Upper-limb PWV was predicted by GFR (beta=-0.24; P<0.001) and mean arterial pressure (beta=0.20; P<0.001). We conclude that, in hypertensive patients with normal renal function, an inverse relationship exists between GFR and stiffness of both central elastic and peripheral muscular arteries. These relations are in part independent from the effect of several confounders, including age, sex, and blood pressure values.", "title": "Relation between renal function within the normal range and central and peripheral arterial stiffness in hypertension." }, { "docid": "27158570", "text": "We performed genome-wide analyses to identify genomic loci that interact with sodium to influence blood pressure (BP) using single-marker-based (1 and 2 df joint tests) and gene-based tests among 1876 Chinese participants of the Genetic Epidemiology Network of Salt-Sensitivity (GenSalt) study. Among GenSalt participants, the average of 3 urine samples was used to estimate sodium excretion. Nine BP measurements were taken using a random zero sphygmomanometer. A total of 2.05 million single-nucleotide polymorphisms were imputed using Affymetrix 6.0 genotype data and the Chinese Han of Beijing and Japanese of Tokyo HapMap reference panel. Promising findings (P<1.00×10(-4)) from GenSalt were evaluated for replication among 775 Chinese participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Single-nucleotide polymorphism and gene-based results were meta-analyzed across the GenSalt and MESA studies to determine genome-wide significance. The 1 df tests identified interactions for UST rs13211840 on diastolic BP (P=3.13×10(-9)). The 2 df tests additionally identified associations for CLGN rs2567241 (P=3.90×10(-12)) and LOC105369882 rs11104632 (P=4.51×10(-8)) with systolic BP. The CLGN variant rs2567241 was also associated with diastolic BP (P=3.11×10(-22)) and mean arterial pressure (P=2.86×10(-15)). Genome-wide gene-based analysis identified MKNK1 (P=6.70×10(-7)), C2orf80 (P<1.00×10(-12)), EPHA6 (P=2.88×10(-7)), SCOC-AS1 (P=4.35×10(-14)), SCOC (P=6.46×10(-11)), CLGN (P=3.68×10(-13)), MGAT4D (P=4.73×10(-11)), ARHGAP42 (P≤1.00×10(-12)), CASP4 (P=1.31×10(-8)), and LINC01478 (P=6.75×10(-10)) that were associated with at least 1 BP phenotype. In summary, we identified 8 novel and 1 previously reported BP loci through the examination of single-nucleotide polymorphism and gene-based interactions with sodium.", "title": "Genome-Wide Gene-Sodium Interaction Analyses on Blood Pressure: The Genetic Epidemiology Network of Salt-Sensitivity Study." }, { "docid": "4647303", "text": "CONTEXT Exposure to cardiovascular risk factors during childhood and adolescence may be associated with the development of atherosclerosis later in life. \n OBJECTIVE To study the relationship between cardiovascular risk factors measured in childhood and adolescence and common carotid artery intima-media thickness (IMT), a marker of preclinical atherosclerosis, measured in adulthood. \n DESIGN, SETTING, AND PARTICIPANTS Population-based, prospective cohort study conducted at 5 centers in Finland among 2229 white adults aged 24 to 39 years who were examined in childhood and adolescence at ages 3 to 18 years in 1980 and reexamined 21 years later, between September 2001 and January 2002. \n MAIN OUTCOME MEASURES Association between cardiovascular risk variables (levels of low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides; LDL-C/HDL-C ratio; systolic and diastolic blood pressure; body mass index; smoking) measured in childhood and adulthood and common carotid artery IMT measured in adulthood. \n RESULTS In multivariable models adjusted for age and sex, IMT in adulthood was significantly associated with childhood LDL-C levels (P =.001), systolic blood pressure (P<.001), body mass index (P =.007), and smoking (P =.02), and with adult systolic blood pressure (P<.001), body mass index (P<.001), and smoking (P =.004). The number of risk factors measured in 12- to 18-year-old adolescents, including high levels (ie, extreme age- and sex-specific 80th percentile) of LDL-C, systolic blood pressure, body mass index, and cigarette smoking, were directly related to carotid IMT measured in young adults at ages 33 through 39 years (P<.001 for both men and women), and remained significant after adjustment for contemporaneous risk variables. The number of risk factors measured at ages 3 to 9 years demonstrated a weak direct relationship with carotid IMT at ages 24 to 30 years in men (P =.02) but not in women (P =.63). \n CONCLUSIONS Risk factor profile assessed in 12- to 18-year-old adolescents predicts adult common carotid artery IMT independently of contemporaneous risk factors. These findings suggest that exposure to cardiovascular risk factors early in life may induce changes in arteries that contribute to the development of atherosclerosis.", "title": "Cardiovascular risk factors in childhood and carotid artery intima-media thickness in adulthood: the Cardiovascular Risk in Young Finns Study." }, { "docid": "13445579", "text": "BACKGROUND AND PURPOSE IAs are found in 2.3% of adults; the mean age at detection is 52 years. Prevalence is <0.5% in young adults. Early studies suggest that 10%-50% of patients with aortic coarctation have IAs. Screening recommendations are variable. We sought to examine the prevalence of IAs through screening with MRA. MATERIALS AND METHODS Consecutive patients older than 16 years of age with coarctation undergoing brain MRA between May 1999 and October 2007 were included. MRA was performed by using a 1.5T scanner with a 3D time-of-flight protocol; simultaneous MR imaging was performed of the heart and aorta. Cerebral MRAs were double-reported by a neuroradiologist. Statistics are described as mean ± SD and median ± range. Continuous variables were compared by using Student t tests and Mann-Whitney U tests (categoric variables, by using the Fisher exact test). \n RESULTS One hundred seventeen MRAs were double-reported. The median age was 29 ± 11 years (range, 16-59 years). IAs were found in 12 patients (10.3%). The mean diameter of IAs was 3.9 mm (range, 2.0-8.0 mm). Patients with aneurysms were older (median, 37 years; range, 16-50 years) than those without (median, 23 years; range, 16-59 years; Z = -2.01, P = .04). Hypertension was more common in those with IAs (IA 83% versus no IA 43%, P = .01). There was no association between ascending aortopathy, bicuspid aortic valves, and IAs. \n CONCLUSIONS Patients with coarctation have a higher prevalence of IAs, occurring at an earlier age than in population studies. Whether routine screening is appropriate for this group of patients is unclear. Hypertension is likely to be an important pathophysiologic factor.", "title": "Results of screening for intracranial aneurysms in patients with coarctation of the aorta." }, { "docid": "8509018", "text": "BACKGROUND Patients with signs and symptoms of heart failure and a normal left ventricular ejection fraction are said to have diastolic heart failure. It has traditionally been thought that the pathophysiological cause of heart failure in these patients is an abnormality in the diastolic properties of the left ventricle; however, this hypothesis remains largely unproven. \n METHODS We prospectively identified 47 patients who met the diagnostic criteria for definite diastolic heart failure; all the patients had signs and symptoms of heart failure, a normal ejection fraction, and an increased left ventricular end-diastolic pressure. Ten patients who had no evidence of cardiovascular disease served as controls. Left ventricular diastolic function was assessed by means of cardiac catheterization and echocardiography. \n RESULTS The patients with diastolic heart failure had abnormal left ventricular relaxation and increased left ventricular chamber stiffness. The mean (+/-SD) time constant for the isovolumic-pressure decline (tau) was longer in the group with diastolic heart failure than in the control group (59+/-14 msec vs. 35+/-10 msec, P=0.01). The diastolic pressure-volume relation was shifted up and to the left in the patients with diastolic heart failure as compared with the controls. The corrected left ventricular passive-stiffness constant was significantly higher in the group with diastolic heart failure than in the control group (0.03+/-0.01 vs. 0.01+/-0.01, P<0.001). \n CONCLUSIONS Patients with heart failure and a normal ejection fraction have significant abnormalities in active relaxation and passive stiffness. In these patients, the pathophysiological cause of elevated diastolic pressures and heart failure is abnormal diastolic function.", "title": "Diastolic heart failure--abnormalities in active relaxation and passive stiffness of the left ventricle." }, { "docid": "31889025", "text": "OBJECTIVES - To study the relative and population-attributable risks of hypertension for the development of congestive heart failure (CHF), to assess the time course of progression from hypertension to CHF, and to identify risk factors that contribute to the development of overt heart failure in hypertensive subjects. \n DESIGN - Inception cohort study. \n SETTING - General community. \n PARTICIPANTS - Original Framingham Heart Study and Framingham Offspring Study participants aged 40 to 89 years and free of CHF. To reflect more contemporary experience, the starting point of this study was January 1, 1970. EXPOSURE MEASURES - Hypertension (blood pressure of at least 140 mm Hg systolic or 90 mm Hg diastolic or current use of medications for treatment of high blood pressure) and other potential CHF risk factors were assessed at periodic clinic examinations. \n OUTCOME MEASURE - The development of CHF. \n RESULTS - A total of 5143 eligible subjects contributed 72422 person-years of observation. During up to 20.1 years of follow-up (mean, 14.1 years), there were 392 new cases of heart failure; in 91% (357/392), hypertension antedated the development of heart failure. Adjusting for age and heart failure risk factors in proportional hazards regression models, the hazard for developing heart failure in hypertensive compared with normotensive subjects was about 2-fold in men and 3-fold in women. Multivariable analyses revealed that hypertension had a high population-attributable risk for CHF, accounting for 39% of cases in men and 59% in women. Among hypertensive subjects, myocardial infarction, diabetes, left ventricular hypertrophy, and valvular heart disease were predictive of increased risk for CHF in both sexes. Survival following the onset of hypertensive CHF was bleak; only 24% of men and 31% of women survived 5 years. \n CONCLUSIONS - Hypertension was the most common risk factor for CHF, and it contributed a large proportion of heart failure cases in this population-based sample. Preventive strategies directed toward earlier and more aggressive blood pressure control are likely to offer the greatest promise for reducing the incidence of CHF and its associated mortality.", "title": "The progression from hypertension to congestive heart failure." } ]

[ { "docid": "2014909", "text": "Myeloid-derived suppressor cells (MDSCs) play critical roles in primary and metastatic cancer progression. MDSC regulation is widely variable even among patients harbouring the same type of malignancy, and the mechanisms governing such heterogeneity are largely unknown. Here, integrating human tumour genomics and syngeneic mammary tumour models, we demonstrate that mTOR signalling in cancer cells dictates a mammary tumour's ability to stimulate MDSC accumulation through regulating G-CSF. Inhibiting this pathway or its activators (for example, FGFR) impairs tumour progression, which is partially rescued by restoring MDSCs or G-CSF. Tumour-initiating cells (TICs) exhibit elevated G-CSF. MDSCs reciprocally increase TIC frequency through activating Notch in tumour cells, forming a feedforward loop. Analyses of primary breast cancers and patient-derived xenografts corroborate these mechanisms in patients. These findings establish a non-canonical oncogenic role of mTOR signalling in recruiting pro-tumorigenic MDSCs and show how defined cancer subsets may evolve to promote and depend on a distinct immune microenvironment.", "title": "Oncogenic mTOR signaling recruits myeloid-derived suppressor cells to promote tumor initiation" } ]

[ { "docid": "4658268", "text": "The mammalian TOR (mTOR) pathway integrates nutrient- and growth factor-derived signals to regulate growth, the process whereby cells accumulate mass and increase in size. mTOR is a large protein kinase and the target of rapamycin, an immunosuppressant that also blocks vessel restenosis and has potential anticancer applications. mTOR interacts with the raptor and GbetaL proteins to form a complex that is the target of rapamycin. Here, we demonstrate that mTOR is also part of a distinct complex defined by the novel protein rictor (rapamycin-insensitive companion of mTOR). Rictor shares homology with the previously described pianissimo from D. discoidieum, STE20p from S. pombe, and AVO3p from S. cerevisiae. Interestingly, AVO3p is part of a rapamycin-insensitive TOR complex that does not contain the yeast homolog of raptor and signals to the actin cytoskeleton through PKC1. Consistent with this finding, the rictor-containing mTOR complex contains GbetaL but not raptor and it neither regulates the mTOR effector S6K1 nor is it bound by FKBP12-rapamycin. We find that the rictor-mTOR complex modulates the phosphorylation of Protein Kinase C alpha (PKCalpha) and the actin cytoskeleton, suggesting that this aspect of TOR signaling is conserved between yeast and mammals.", "title": "Rictor, a Novel Binding Partner of mTOR, Defines a Rapamycin-Insensitive and Raptor-Independent Pathway that Regulates the Cytoskeleton" }, { "docid": "24612804", "text": "IL-17 is a novel, CD4+ T cell-restricted cytokine. In vivo, it stimulates hematopoiesis and causes neutrophilia consisting of mature granulocytes. In this study, we show that IL-17-mediated granulopoiesis requires G-CSF release and the presence or induction of the transmembrane form of stem cell factor (SCF) for optimal granulopoiesis. However, IL-17 also protects mice from G-CSF neutralization-induced neutropenia. G-CSF neutralization completely reversed IL-17-induced BM progenitor expansion, whereas splenic CFU-GM/CFU-granulocyte-erythrocyte-megakaryocyte-monocyte was only reduced by 50% in both Sl/Sld and littermate control mice. Thus, there remained a significant SCF/G-CSF-independent effect of IL-17 on splenic granulopoiesis, resulting in a preservation of mature circulating granulocytes. IL-17 is a cytokine that potentially interconnects lymphocytic and myeloid host defense and may have potential for therapeutic development.", "title": "Requirement of endogenous stem cell factor and granulocyte-colony-stimulating factor for IL-17-mediated granulopoiesis." }, { "docid": "22174015", "text": "The PI3K-Akt-mTORC1 axis contributes to the activation, survival, and proliferation of CD4(+) T cells upon stimulation through TCR and CD28. Here, we demonstrate that the suppression of this axis by deletion of p85α or PI3K/mTORC1 inhibitors as well as T cell-specific deletion of raptor, an essential component of mTORC1, impairs Th17 differentiation in vitro and in vivo in a S6K1/2-dependent fashion. Inhibition of PI3K-Akt-mTORC1-S6K1 axis impairs the downregulation of Gfi1, a negative regulator of Th17 differentiation. Furthermore, we demonstrate that S6K2, a nuclear counterpart of S6K1, is induced by the PI3K-Akt-mTORC1 axis, binds RORγ, and carries RORγ to the nucleus. These results point toward a pivotal role of PI3K-Akt-mTORC1-S6K1/2 axis in Th17 differentiation.", "title": "PI3K-Akt-mTORC1-S6K1/2 axis controls Th17 differentiation by regulating Gfi1 expression and nuclear translocation of RORγ." }, { "docid": "19510470", "text": "Cancer stem cells have been proposed to be important for initiation, maintenance and recurrence of various malignancies, including acute myeloid leukemia (AML). We have previously reported that CD34+CD38− human primary AML stem cells residing in the endosteal region of the bone marrow are relatively chemotherapy resistant. Using a NOD/SCID/IL2rγnull mouse model of human AML, we now show that the AML stem cells in the endosteal region are cell cycle quiescent and that these stem cells can be induced to enter the cell cycle by treatment with granulocyte colony-stimulating factor (G-CSF). In combination with cell cycle-dependent chemotherapy, G-CSF treatment significantly enhances induction of apoptosis and elimination of human primary AML stem cells in vivo. The combination therapy leads to significantly increased survival of secondary recipients after transplantation of leukemia cells compared with chemotherapy alone.", "title": "Induction of cell cycle entry eliminates human leukemia stem cells in a mouse model of AML" }, { "docid": "13509809", "text": "The bone marrow (BM) niche comprises multiple cell types that regulate hematopoietic stem/progenitor cell (HSPC) migration out of the niche and into the circulation. Here, we demonstrate that osteocytes, the major cellular component of mature bone, are regulators of HSPC egress. Granulocyte colony-stimulating factor (G-CSF), used clinically to mobilize HSPCs, induces changes in the morphology and gene expression of the osteocytic network that precedes changes in osteoblasts. This rapid response is likely under control of the sympathetic nervous system, since osteocytes express the β2-adrenergic receptor and surgical sympathectomy prevents it. Mice with targeted ablation of osteocytes or a disrupted osteocyte network have comparable numbers of HSPCs in the BM but fail to mobilize HSPCs in response to G-CSF. Taken together, these results indicate that the BM/bone niche interface is critically controlled from inside of the bone matrix and establish an important physiological role for skeletal tissues in hematopoietic function.", "title": "Matrix-embedded osteocytes regulate mobilization of hematopoietic stem/progenitor cells." }, { "docid": "15248287", "text": "Neutrophil apoptosis is a highly regulated process essential for inflammation resolution, the molecular mechanisms of which are only partially elucidated. In this study, we describe a survival pathway controlled by proliferating cell nuclear antigen (PCNA), a nuclear factor involved in DNA replication and repairing of proliferating cells. We show that mature neutrophils, despite their inability to proliferate, express high levels of PCNA exclusively in their cytosol and constitutively associated with procaspases, presumably to prevent their activation. Notably, cytosolic PCNA abundance decreased during apoptosis, and increased during in vitro and in vivo exposure to the survival factor granulocyte colony-stimulating factor (G-CSF). Peptides derived from the cyclin-dependent kinase inhibitor p21, which compete with procaspases to bind PCNA, triggered neutrophil apoptosis thus demonstrating that specific modification of PCNA protein interactions affects neutrophil survival. Furthermore, PCNA overexpression rendered neutrophil-differentiated PLB985 myeloid cells significantly more resistant to TNF-related apoptosis-inducing ligand- or gliotoxin-induced apoptosis. Conversely, a decrease in PCNA expression after PCNA small interfering RNA transfection sensitized these cells to apoptosis. Finally, a mutation in the PCNA interdomain-connecting loop, the binding site for many partners, significantly decreased the PCNA-mediated antiapoptotic effect. These results identify PCNA as a regulator of neutrophil lifespan, thereby highlighting a novel target to potentially modulate pathological inflammation.", "title": "Proliferating cell nuclear antigen acts as a cytoplasmic platform controlling human neutrophil survival" }, { "docid": "188911", "text": "Antigen-presenting, major histocompatibility complex (MHC) class II-rich dendritic cells are known to arise from bone marrow. However, marrow lacks mature dendritic cells, and substantial numbers of proliferating less-mature cells have yet to be identified. The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II-negative precursors in marrow. A key step is to remove the majority of nonadherent, newly formed granulocytes by gentle washes during the first 2-4 d of culture. This leaves behind proliferating clusters that are loosely attached to a more firmly adherent \"stroma. \" At days 4-6 the clusters can be dislodged, isolated by 1-g sedimentation, and upon reculture, large numbers of dendritic cells are released. The latter are readily identified on the basis of their distinct cell shape, ultrastructure, and repertoire of antigens, as detected with a panel of monoclonal antibodies. The dendritic cells express high levels of MHC class II products and act as powerful accessory cells for initiating the mixed leukocyte reaction. Neither the clusters nor mature dendritic cells are generated if macrophage colony-stimulating factor rather than granulocyte/macrophage colony-stimulating factor (GM-CSF) is applied. Therefore, GM-CSF generates all three lineages of myeloid cells (granulocytes, macrophages, and dendritic cells). Since > 5 x 10(6) dendritic cells develop in 1 wk from precursors within the large hind limb bones of a single animal, marrow progenitors can act as a major source of dendritic cells. This feature should prove useful for future molecular and clinical studies of this otherwise trace cell type.", "title": "Generation of large numbers of dendritic cells from mouse bone marrow cultures supplemented with granulocyte/macrophage colony-stimulating factor" }, { "docid": "1818578", "text": "Amino-acid producers have traditionally been developed by repeated random mutagenesis owing to the difficulty in rationally engineering the complex and highly regulated metabolic network. Here, we report the development of the genetically defined L-threonine overproducing Escherichia coli strain by systems metabolic engineering. Feedback inhibitions of aspartokinase I and III (encoded by thrA and lysC, respectively) and transcriptional attenuation regulations (located in thrL) were removed. Pathways for Thr degradation were removed by deleting tdh and mutating ilvA. The metA and lysA genes were deleted to make more precursors available for Thr biosynthesis. Further target genes to be engineered were identified by transcriptome profiling combined with in silico flux response analysis, and their expression levels were manipulated accordingly. The final engineered E. coli strain was able to produce Thr with a high yield of 0.393 g per gram of glucose, and 82.4 g/l Thr by fed-batch culture. The systems metabolic engineering strategy reported here may be broadly employed for developing genetically defined organisms for the efficient production of various bioproducts.", "title": "Systems metabolic engineering of Escherichia coli for L-threonine production" }, { "docid": "6334188", "text": "BACKGROUND Chemotherapy-induced febrile neutropenia (FN) is a clinically important complication that affects patient outcome by delaying chemotherapy doses or reducing dose intensity. Risk of FN depends on chemotherapy- and patient-level factors. We sought to determine the effects of chronic comorbidities on risk of FN. \n DESIGN We conducted a cohort study to examine the association between a variety of chronic comorbidities and risk of FN in patients diagnosed with six types of cancer (non-Hodgkin lymphoma and breast, colorectal, lung, ovary, and gastric cancer) from 2000 to 2009 who were treated with chemotherapy at Kaiser Permanente Southern California, a large managed care organization. We excluded those patients who received primary prophylactic granulocyte colony-stimulating factor. History of comorbidities and FN events were identified using electronic medical records. Cox models adjusting for propensity score, stratified by cancer type, were used to determine the association between comorbid conditions and FN. Models that additionally adjusted for cancer stage, baseline neutrophil count, chemotherapy regimen, and dose reduction were also evaluated. \n RESULTS A total of 19 160 patients with mean age of 60 years were included; 963 (5.0%) developed FN in the first chemotherapy cycle. Chronic obstructive pulmonary disease [hazard ratio (HR) = 1.30 (1.07-1.57)], congestive heart failure [HR = 1.43 (1.00-1.98)], HIV infection [HR = 3.40 (1.90-5.63)], autoimmune disease [HR = 2.01 (1.10-3.33)], peptic ulcer disease [HR = 1.57 (1.05-2.26)], renal disease [HR = 1.60 (1.21-2.09)], and thyroid disorder [HR = 1.32 (1.06-1.64)] were all associated with a significantly increased FN risk. \n CONCLUSIONS These results provide evidence that history of several chronic comorbidities increases risk of FN, which should be considered when managing patients during chemotherapy.", "title": "History of chronic comorbidity and risk of chemotherapy-induced febrile neutropenia in cancer patients not receiving G-CSF prophylaxis." }, { "docid": "470625", "text": "Genomic alterations leading to aberrant activation of cyclin/cyclin-dependent kinase (cdk) complexes drive the pathogenesis of many common human tumor types. In the case of glioblastoma multiforme (GBM), these alterations are most commonly due to homozygous deletion of p16(INK4a) and less commonly due to genomic amplifications of individual genes encoding cyclins or cdks. Here, we describe deletion of the p18(INK4c) cdk inhibitor as a novel genetic alteration driving the pathogenesis of GBM. Deletions of p18(INK4c) often occurred in tumors also harboring homozygous deletions of p16(INK4a). Expression of p18(INK4c) was completely absent in 43% of GBM primary tumors studied by immunohistochemistry. Lentiviral reconstitution of p18(INK4c) expression at physiologic levels in p18(INK4c)-deficient but not p18(INK4c)-proficient GBM cells led to senescence-like G(1) cell cycle arrest. These studies identify p18(INK4c) as a GBM tumor suppressor gene, revealing an additional mechanism leading to aberrant activation of cyclin/cdk complexes in this terrible malignancy.", "title": "Identification of p18 INK4c as a tumor suppressor gene in glioblastoma multiforme." }, { "docid": "654735", "text": "Glioma is a most common type of primary brain tumors. Extracellular vesicles, in the form of exosomes, are known to mediate cell-cell communication by transporting cell-derived proteins and nucleic acids, including various microRNAs (miRNAs). Here we examined the cerebrospinal fluid (CSF) from patients with recurrent glioma for the levels of cancer-related miRNAs, and evaluated the values for prognosis by comparing the measures of CSF-, serum-, and exosome-contained miR-21 levels. Samples from seventy glioma patients following surgery were compared with those from brain trauma patients as a non-tumor control group. Exosomal miR-21 levels in the CSF of glioma patients were found significantly higher than in the controls; whereas no difference was detected in serum-derived exosomal miR-21 expression. The CSF-derived exosomal miR-21 levels correlated with tumor spinal/ventricle metastasis and the recurrence with anatomical site preference. From additional 198 glioma tissue samples, we verified that miR-21 levels associated with tumor grade of diagnosis and negatively correlated with the median values of patient overall survival time. We further used a lentiviral inhibitor to suppress miR-21 expression in U251 cells. The results showed that the levels of miR-21 target genes of PTEN, RECK and PDCD4 were up-regulated at protein levels. Therefore, we concluded that the exosomal miR-21 levels could be demonstrated as a promising indicator for glioma diagnosis and prognosis, particularly with values to predict tumor recurrence or metastasis.", "title": "Exosomal levels of miRNA-21 from cerebrospinal fluids associated with poor prognosis and tumor recurrence of glioma patients" }, { "docid": "46565020", "text": "BACKGROUND AN1792 (beta-amyloid [Abeta]1-42) immunization reduces Abeta plaque burden and preserves cognitive function in APP transgenic mice. The authors report the results of a phase IIa immunotherapy trial of AN1792(QS-21) in patients with mild to moderate Alzheimer disease (AD) that was interrupted because of meningoencephalitis in 6% of immunized patients. \n METHODS This randomized, multicenter, placebo-controlled, double-blind trial of IM AN1792 225 microg plus the adjuvant QS-21 50 microg (300 patients) and saline (72 patients) included patients aged 50 to 85 years with probable AD, Mini-Mental State Examination (MMSE) 15 to 26. Injections were planned for months 0, 1, 3, 6, 9, and 12. Safety and tolerability were evaluated, and pilot efficacy (AD Assessment Scale-Cognitive Subscale [ADAS-Cog], MRI, neuropsychological test battery [NTB], CSF tau, and Abeta42) was assessed in anti-AN1792 antibody responder patients (immunoglobulin G titer > or = 1:2,200). \n RESULTS Following reports of meningoencephalitis (overall 18/300 [6%]), immunization was stopped after one (2 patients), two (274 patients), or three (24 patients) injections. Of the 300 AN1792(QS-21)-treated patients, 59 (19.7%) developed the predetermined antibody response. Double-blind assessments were maintained for 12 months. No significant differences were found between antibody responder and placebo groups for ADAS-Cog, Disability Assessment for Dementia, Clinical Dementia Rating, MMSE, or Clinical Global Impression of Change, but analyses of the z-score composite across the NTB revealed differences favoring antibody responders (0.03 +/- 0.37 vs -0.20 +/- 0.45; p = 0.020). In the small subset of subjects who had CSF examinations, CSF tau was decreased in antibody responders (n = 11) vs placebo subjects (n = 10; p < 0.001). \n CONCLUSION Although interrupted, this trial provides an indication that Abeta immunotherapy may be useful in Alzheimer disease.", "title": "Clinical effects of Abeta immunization (AN1792) in patients with AD in an interrupted trial." }, { "docid": "23816832", "text": "Diagnosis of multiple sclerosis (MS) requires the exclusion of other possible diagnoses. For this reason, the cerebrospinal fluid (CSF) should be routinely analysed in patients with a first clinical event suggestive of MS. CSF analysis is no longer mandatory for diagnosis of relapsing–remitting MS, as long as MRI diagnostic criteria are fulfilled. However, caution is required in diagnosing MS in patients with negative MRI findings or in the absence of CSF analysis, as CSF investigation is useful to eliminate other causes of disease. The detection of oligoclonal IgG bands in CSF has potential prognostic value and is helpful for clinical decision-making. In addition, CSF analysis is important for research into the pathogenesis of MS. Pathophysiological and neurodegenerative findings of inflammation in MS have been derived from CSF investigations. Novel CSF biomarkers, though not yet validated, have been identified for diagnosis of MS and for ascertaining disease activity, prognosis and response to treatment, and are likely to increase in number with modern detection techniques. In this Review, we summarize CSF findings that shed light on the differential diagnosis of MS, and highlight the potential of novel biomarkers for this disease that could advance understanding of its pathophysiology.", "title": "The utility of cerebrospinal fluid analysis in patients with multiple sclerosis" }, { "docid": "45449835", "text": "Myelin-directed autoimmunity is considered to play a key role in the pathogenesis of multiple sclerosis (MS). Increased production of both pro- and anti-inflammatory cytokines is a common finding in MS. Interleukin-17 (IL-17) is a recently described cytokine produced in humans almost exclusively by activated memory T cells, which can induce the production of proinflammatory cytokines and chemokines from parenchymal cells and macrophages. In situ hybridisation with synthetic oligonucleotide probes was adopted to detect and enumerate IL-17 mRNA expressing mononuclear cells (MNC) in blood and cerebrospinal fluid (CSF) from patients with MS and control individuals. Numbers of IL-17 mRNA expressing blood MNC were higher in patients with MS and acute aseptic meningoencephalitis (AM) compared to healthy individuals. Higher numbers of IL-17 mRNA expressing blood MNC were detected in MS patients examined during clinical exacerbation compared to remission. Patients with MS had higher numbers of IL-17 mRNA expressing MNC in CSF compared to blood. This increase in numbers of IL-17 mRNA expressing MNC in CSF was not observed in patients with AM. Our results thus demonstrate increased numbers of IL-17 mRNA expressing MNC in MS with higher numbers in CSF than blood, and with the highest numbers in blood during clinical exacerbations.", "title": "Interleukin-17 mRNA expression in blood and CSF mononuclear cells is augmented in multiple sclerosis." }, { "docid": "24721866", "text": "Macrophage-derived foam cells play important roles in the progression of atherosclerosis. We reported previously that ERK1/2-dependent granulocyte/macrophage colony-stimulating factor (GM-CSF) expression, leading to p38 MAPK/ Akt signaling, is important for oxidized low density lipoprotein (Ox-LDL)-induced macrophage proliferation. Here, we investigated whether activation of AMP-activated protein kinase (AMPK) could suppress macrophage proliferation. Ox-LDL-induced proliferation of mouse peritoneal macrophages was assessed by [(3)H]thymidine incorporation and cell counting assays. The proliferation was significantly inhibited by the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) and restored by dominant-negative AMPKalpha1, suggesting that AMPK activation suppressed macrophage proliferation. AICAR partially suppressed Ox-LDL-induced ERK1/2 phosphorylation and GM-CSF expression, suggesting that another mechanism is also involved in the AICAR-mediated suppression of macrophage proliferation. AICAR suppressed GM-CSF-induced macrophage proliferation without suppressing p38 MAPK/Akt signaling. GM-CSF suppressed p53 phosphorylation and expression and induced Rb phosphorylation. Overexpression of p53 or p27(kip) suppressed GM-CSF-induced macrophage proliferation. AICAR induced cell cycle arrest, increased p53 phosphorylation and expression, and suppressed GM-CSF-induced Rb phosphorylation via AMPK activation. Moreover, AICAR induced p21(cip) and p27(kip) expression via AMPK activation, and small interfering RNA (siRNA) of p21(cip) and p27(kip) restored AICAR-mediated suppression of macrophage proliferation. In conclusion, AMPK activation suppressed Ox-LDL-induced macrophage proliferation by suppressing GM-CSF expression and inducing cell cycle arrest. These effects of AMPK activation may represent therapeutic targets for atherosclerosis.", "title": "Activation of AMP-activated protein kinase suppresses oxidized low-density lipoprotein-induced macrophage proliferation." }, { "docid": "20754359", "text": "After cell-to-cell transmission, HTLV-I increases its viral genome by de novo infection and proliferation of infected cells. Proliferation of infected cells is clonal and persistent in vivo. During the carrier state, infected cells are selected in vivo by the host's immune system, the genetic and epigenetic environment of proviral integration sites, and other factors. In leukemic cells, tax gene expression is frequently impaired by genetic and epigenetic mechanisms. Such loss of Tax expression enables ATL cells to escape the host immune system. On the other hand, ATL cells acquire the ability to proliferate without Tax by intracellular genetic and epigenetic changes. Despite advances in support and the development of novel treatment agents, the prognosis for ATLL remains poor. A number of therapies, however, do appear to improve prognosis compared to CHOP (VEPA). These include interferon-α plus zidovudine (probably after 1–2 cycles of CHOP), intensive chemotherapy as in LSG-15 with G-CSF support and Allo-SCT (which includes the potential for cure). Emerging novel approaches include HDAC inhibitors, monoclonal antibodies, and proteasome inhibitors. Comparison between different therapeutic approaches is complicated by the range of natural history of ATLL, different recruitments of naïve-to-therapy, refractory or relapsed patients, and variations in the reporting of outcome that frequently excludes difficult-to-evaluate patients. Moreover, results from relatively small proof-of-principle studies have not been extended with randomized, controlled trials. As a result, currently, there is no clear evidence to support the value of any particular treatment approach over others. To avoid further unnecessary patient suffering and to identify optimal therapy as rapidly as possible, large randomized, controlled trials encompassing multicenter, international collaborations will be necessary.", "title": "Natural history of adult T-cell leukemia/lymphoma and approaches to therapy" }, { "docid": "52874170", "text": "CONTEXT Diagnostic lumbar punctures (LPs), commonly used to rule out meningitis, are associated with adverse events. \n OBJECTIVE To systematically review the evidence about diagnostic LP techniques that may decrease the risk of adverse events and the evidence about test accuracy of cerebrospinal fluid (CSF) analysis in adult patients with suspected bacterial meningitis. \n DATA SOURCES We searched the Cochrane Library, MEDLINE (using Ovid and PubMed) from 1966 to January 2006 and EMBASE from 1980 to January 2006 without language restrictions to identify relevant studies and identified others from the bibliographies of retrieved articles. STUDY SELECTION We included randomized trials of patients aged 18 years or older undergoing interventions to facilitate a successful diagnostic LP or to potentially reduce adverse events. Studies assessing the accuracy of biochemical analysis of the CSF for possible bacterial meningitis were also identified. \n DATA EXTRACTION Two investigators independently appraised study quality and extracted relevant data. For studies of the LP technique, data on the intervention and the outcome were extracted. For studies of the laboratory diagnosis of bacterial meningitis, data on the reference standard and test accuracy were extracted. \n DATA SYNTHESIS We found 15 randomized trials. A random-effects model was used for quantitative synthesis. Five studies of 587 patients compared atraumatic needles with standard needles and found a nonsignificant decrease in the odds of headache with an atraumatic needle (absolute risk reduction [ARR], 12.3%; 95% confidence interval [CI], -1.72% to 26.2%). Reinsertion of the stylet before needle removal decreased the risk of headache (ARR, 11.3%; 95% CI, 6.50%-16.2%). The combined results from 4 studies of 717 patients showed a nonsignificant decrease in headache in patients who were mobilized after LP (ARR, 2.9%; 95% CI, -3.4 to 9.3%). Four studies on the accuracy of biochemical analysis of CSF in patients with suspected meningitis met inclusion criteria. A CSF-blood glucose ratio of 0.4 or less (likelihood ratio [LR], 18; 95% CI, 12-27]), CSF white blood cell count of 500/muL or higher (LR, 15; 95% CI, 10-22), and CSF lactate level of 31.53 mg/dL or more (> or =3.5 mmol/L; LR, 21; 95% CI, 14-32) accurately diagnosed bacterial meningitis. \n CONCLUSIONS These data suggest that small-gauge, atraumatic needles may decrease the risk of headache after diagnostic LP. Reinsertion of the stylet before needle removal should occur and patients do not require bed rest after the procedure. Future research should focus on evaluating interventions to optimize the success of a diagnostic LP and to enhance training in procedural skills.", "title": "How do I perform a lumbar puncture and analyze the results to diagnose bacterial meningitis?" }, { "docid": "10207180", "text": "INTRODUCTION The β-secretase enzyme, β-site amyloid precursor protein-cleaving enzyme 1 (BACE1), cleaves amyloid precursor protein (APP) in the first step in β-amyloid (Aβ) peptide production. Thus, BACE1 is a key target for candidate disease-modifying treatment of Alzheimer's disease. In a previous exploratory Aβ biomarker study, we found that BACE1 inhibitor treatment resulted in decreased levels of Aβ1-34 together with increased Aβ5-40, suggesting that these Aβ species may be novel pharmacodynamic biomarkers in clinical trials. We have now examined whether the same holds true in humans. \n METHODS In an investigator-blind, placebo-controlled and randomized study, healthy subjects (n =18) were randomly assigned to receive a single dose of 30 mg of LY2811376 (n =6), 90 mg of LY2811376 (n =6), or placebo (n =6). We used hybrid immunoaffinity-mass spectrometry (HI-MS) and enzyme-linked immunosorbent assays to monitor a variety of Aβ peptides. \n RESULTS Here, we demonstrate dose-dependent changes in cerebrospinal fluid (CSF) Aβ1-34, Aβ5-40 and Aβ5-X after treatment with the BACE1-inhibitor LY2811376. Aβ5-40 and Aβ5-X increased dose-dependently, as reflected by two independent methods, while Aβ1-34 dose-dependently decreased. \n CONCLUSION Using HI-MS for the first time in a study where subjects have been treated with a BACE inhibitor, we confirm that CSF Aβ1-34 may be useful in clinical trials on BACE1 inhibitors to monitor target engagement. Since it is less hydrophobic than longer Aβ species, it is less susceptible to preanalytical confounding factors and may thus be a more stable marker. By independent measurement techniques, we also show that BACE1 inhibition in humans is associated with APP-processing into N-terminally truncated Aβ peptides via a BACE1-independent pathway. \n TRIAL REGISTRATION ClinicalTrials.gov NCT00838084. Registered: First received: January 23, 2009, Last updated: July 14, 2009, Last verified: July 2009.", "title": "β-site amyloid precursor protein-cleaving enzyme 1(BACE1) inhibitor treatment induces Aβ5-X peptides through alternative amyloid precursor protein cleavage" }, { "docid": "17450673", "text": "INTRODUCTION Various perinatal factors, including birth weight, birth order, maternal age, gestational age, twin status, and parental smoking, have been postulated to affect breast cancer risk in daughters by altering the hormonal environment of the developing fetal mammary glands. Despite ample biologic plausibility, epidemiologic studies to date have yielded conflicting results. We investigated the associations between perinatal factors and subsequent breast cancer risk through meta-analyses. \n METHODS We reviewed breast cancer studies published from January 1966 to February 2007 that included data on birth weight, birth order, maternal age, gestational age, twin status, and maternal or paternal smoking. Meta-analyses using random effect models were employed to summarize the results. \n RESULTS We found that heavier birth weights were associated with increased breast cancer risk, with studies involving five categories of birth weight identifying odds ratios (ORs) of 1.24 (95% confidence interval [CI] 1.04 to 1.48) for 4,000 g or more and 1.15 (95% CI 1.04 to 1.26) for 3,500 g to 3,999 g, relative to a birth weight of 2,500 to 2,599 g. These studies provided no support for a J-shaped relationship of birthweight to risk. Support for an association with birthweight was also derived from studies based on three birth weight categories (OR 1.15 [95% CI 1.01 to 1.31] for > or =4,000 g relative to <3,000 g) and two birth weight categories (OR 1.09 [95% CI 1.02 to 1.18] for > or =3,000 g relative to <3,000 g). Women born to older mothers and twins were also at some increased risk, but the results were heterogeneous across studies and publication years. Birth order, prematurity, and maternal smoking were unrelated to breast cancer risk. \n CONCLUSION Our findings provide some support for the hypothesis that in utero exposures reflective of higher endogenous hormone levels could affect risk for development of breast cancer in adulthood.", "title": "Intrauterine environments and breast cancer risk: meta-analysis and systematic review" } ]

[ { "docid": "40349336", "text": "Developmental abnormalities, cancer, and premature aging each have been linked to defects in the DNA damage response (DDR). Mutations in the ATR checkpoint regulator cause developmental defects in mice (pregastrulation lethality) and humans (Seckel syndrome). Here we show that eliminating ATR in adult mice leads to defects in tissue homeostasis and the rapid appearance of age-related phenotypes, such as hair graying, alopecia, kyphosis, osteoporosis, thymic involution, fibrosis, and other abnormalities. Histological and genetic analyses indicate that ATR deletion causes acute cellular loss in tissues in which continuous cell proliferation is required for maintenance. Importantly, thymic involution, alopecia, and hair graying in ATR knockout mice were associated with dramatic reductions in tissue-specific stem and progenitor cells and exhaustion of tissue renewal and homeostatic capacity. In aggregate, these studies suggest that reduced regenerative capacity in adults via deletion of a developmentally essential DDR gene is sufficient to cause the premature appearance of age-related phenotypes.", "title": "Deletion of the developmentally essential gene ATR in adult mice leads to age-related phenotypes and stem cell loss." } ]

[ { "docid": "12909503", "text": "DNA damage encountered by DNA replication forks poses risks of genome destabilization, a precursor to carcinogenesis. Damage checkpoint systems cause cell cycle arrest, promote repair and induce programed cell death when damage is severe. Checkpoints are critical parts of the DNA damage response network that act to suppress cancer. DNA damage and perturbation of replication machinery causes replication stress, characterized by accumulation of single-stranded DNA bound by replication protein A (RPA), which triggers activation of ataxia telangiectasia and Rad3 related (ATR) and phosphorylation of the RPA32, subunit of RPA, leading to Chk1 activation and arrest. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) [a kinase related to ataxia telangiectasia mutated (ATM) and ATR] has well characterized roles in DNA double-strand break repair, but poorly understood roles in replication stress-induced RPA phosphorylation. We show that DNA-PKcs mutant cells fail to arrest replication following stress, and mutations in RPA32 phosphorylation sites targeted by DNA-PKcs increase the proportion of cells in mitosis, impair ATR signaling to Chk1 and confer a G2/M arrest defect. Inhibition of ATR and DNA-PK (but not ATM), mimic the defects observed in cells expressing mutant RPA32. Cells expressing mutant RPA32 or DNA-PKcs show sustained H2AX phosphorylation in response to replication stress that persists in cells entering mitosis, indicating inappropriate mitotic entry with unrepaired damage.", "title": "Distinct roles for DNA-PK, ATM and ATR in RPA phosphorylation and checkpoint activation in response to replication stress" }, { "docid": "14178995", "text": "The genetic diseases Hutchinson-Gilford progeria syndrome (HGPS) and restrictive dermopathy (RD) arise from accumulation of farnesylated prelamin A because of defects in the lamin A maturation pathway. Both of these diseases exhibit symptoms that can be viewed as accelerated aging. The mechanism by which accumulation of farnesylated prelamin A leads to these accelerated aging phenotypes is not understood. Here we present evidence that in HGPS and RD fibroblasts, DNA damage checkpoints are persistently activated because of the compromise in genomic integrity. Inactivation of checkpoint kinases Ataxia-telangiectasia-mutated (ATM) and ATR (ATM- and Rad3-related) in these patient cells can partially overcome their early replication arrest. Treatment of patient cells with a protein farnesyltransferase inhibitor (FTI) did not result in reduction of DNA double-strand breaks and damage checkpoint signaling, although the treatment significantly reversed the aberrant shape of their nuclei. This suggests that DNA damage accumulation and aberrant nuclear morphology are independent phenotypes arising from prelamin A accumulation in these progeroid syndromes. Since DNA damage accumulation is an important contributor to the symptoms of HGPS, our results call into question the possibility of treatment of HGPS with FTIs alone.", "title": "Summary" }, { "docid": "3113630", "text": "Ataxia telangiectasia is a neurodegenerative disease caused by mutation of the Atm gene. Here we report that ataxia telangiectasia mutated (ATM) deficiency causes nuclear accumulation of histone deacetylase 4 (HDAC4) in neurons and promotes neurodegeneration. Nuclear HDAC4 binds to chromatin, as well as to myocyte enhancer factor 2A (MEF2A) and cAMP-responsive element binding protein (CREB), leading to histone deacetylation and altered neuronal gene expression. Blocking either HDAC4 activity or its nuclear accumulation blunts these neurodegenerative changes and rescues several behavioral abnormalities of ATM-deficient mice. Full rescue of the neurodegeneration, however, also requires the presence of HDAC4 in the cytoplasm, suggesting that the ataxia telangiectasia phenotype results both from a loss of cytoplasmic HDAC4 as well as its nuclear accumulation. To remain cytoplasmic, HDAC4 must be phosphorylated. The activity of the HDAC4 phosphatase, protein phosphatase 2A (PP2A), is downregulated by ATM-mediated phosphorylation. In ATM deficiency, enhanced PP2A activity leads to HDAC4 dephosphorylation and the nuclear accumulation of HDAC4. Our results define a crucial role of the cellular localization of HDAC4 in the events leading to ataxia telangiectasia neurodegeneration.", "title": "Nuclear accumulation of HDAC4 in ATM deficiency promotes neurodegeneration in ataxia-telangiectasia" }, { "docid": "39225849", "text": "The Bloom syndrome helicase (BLM) is critical for genomic stability. A defect in BLM activity results in the cancer-predisposing Bloom syndrome (BS). Here, we report that BLM-deficient cell lines and primary fibroblasts display an endogenously activated DNA double-strand break checkpoint response with prominent levels of phosphorylated histone H2AX (gamma-H2AX), Chk2 (p(T68)Chk2), and ATM (p(S1981)ATM) colocalizing in nuclear foci. Interestingly, the mitotic fraction of gamma-H2AX foci did not seem to be higher in BLM-deficient cells, indicating that these lesions form transiently during interphase. Pulse labeling with iododeoxyuridine and immunofluorescence microscopy showed the colocalization of gamma-H2AX, ATM, and Chk2 together with replication foci. Those foci costained for Rad51, indicating homologous recombination at these replication sites. We therefore analyzed replication in BS cells using a single molecule approach on combed DNA fibers. In addition to a higher frequency of replication fork barriers, BS cells displayed a reduced average fork velocity and global reduction of interorigin distances indicative of an elevated frequency of origin firing. Because BS is one of the most penetrant cancer-predisposing hereditary diseases, it is likely that the lack of BLM engages the cells in a situation similar to precancerous tissues with replication stress. To our knowledge, this is the first report of high ATM-Chk2 kinase activation and its linkage to replication defects in a BS model.", "title": "Endogenous gamma-H2AX-ATM-Chk2 checkpoint activation in Bloom's syndrome helicase deficient cells is related to DNA replication arrested forks." }, { "docid": "43192375", "text": "Adipose tissue macrophages (ATMs) infiltrate adipose tissue during obesity and contribute to insulin resistance. We hypothesized that macrophages migrating to adipose tissue upon high-fat feeding may differ from those that reside there under normal diet conditions. To this end, we found a novel F4/80(+)CD11c(+) population of ATMs in adipose tissue of obese mice that was not seen in lean mice. ATMs from lean mice expressed many genes characteristic of M2 or \"alternatively activated\" macrophages, including Ym1, arginase 1, and Il10. Diet-induced obesity decreased expression of these genes in ATMs while increasing expression of genes such as those encoding TNF-alpha and iNOS that are characteristic of M1 or \"classically activated\" macrophages. Interestingly, ATMs from obese C-C motif chemokine receptor 2-KO (Ccr2-KO) mice express M2 markers at levels similar to those from lean mice. The antiinflammatory cytokine IL-10, which was overexpressed in ATMs from lean mice, protected adipocytes from TNF-alpha-induced insulin resistance. Thus, diet-induced obesity leads to a shift in the activation state of ATMs from an M2-polarized state in lean animals that may protect adipocytes from inflammation to an M1 proinflammatory state that contributes to insulin resistance.", "title": "Obesity induces a phenotypic switch in adipose tissue macrophage polarization." }, { "docid": "13791206", "text": "Defective DNA repair by homologous recombination (HR) is thought to be a major contributor to tumorigenesis in individuals carrying Brca1 mutations. Here, we show that DNA breaks in Brca1-deficient cells are aberrantly joined into complex chromosome rearrangements by a process dependent on the nonhomologous end-joining (NHEJ) factors 53BP1 and DNA ligase 4. Loss of 53BP1 alleviates hypersensitivity of Brca1 mutant cells to PARP inhibition and restores error-free repair by HR. Mechanistically, 53BP1 deletion promotes ATM-dependent processing of broken DNA ends to produce recombinogenic single-stranded DNA competent for HR. In contrast, Lig4 deficiency does not rescue the HR defect in Brca1 mutant cells but prevents the joining of chromatid breaks into chromosome rearrangements. Our results illustrate that HR and NHEJ compete to process DNA breaks that arise during DNA replication and that shifting the balance between these pathways can be exploited to selectively protect or kill cells harboring Brca1 mutations.", "title": "53BP1 Inhibits Homologous Recombination in Brca1-Deficient Cells by Blocking Resection of DNA Breaks" }, { "docid": "32721137", "text": "Although 75% of endometrial cancers are treated at an early stage, 15% to 20% of these recur. We performed an integrated analysis of genome-wide expression and copy-number data for primary endometrial carcinomas with extensive clinical and histopathological data to detect features predictive of recurrent disease. Unsupervised analysis of the expression data distinguished 2 major clusters with strikingly different phenotypes, including significant differences in disease-free survival. To identify possible mechanisms for these differences, we performed a global genomic survey of amplifications, deletions, and loss of heterozygosity, which identified 11 significantly amplified and 13 significantly deleted regions. Amplifications of 3q26.32 harboring the oncogene PIK3CA were associated with poor prognosis and segregated with the aggressive transcriptional cluster. Moreover, samples with PIK3CA amplification carried signatures associated with in vitro activation of PI3 kinase (PI3K), a signature that was shared by aggressive tumors without PIK3CA amplification. Tumors with loss of PTEN expression or PIK3CA overexpression that did not have PIK3CA amplification also shared the PI3K activation signature, high protein expression of the PI3K pathway member STMN1, and an aggressive phenotype in test and validation datasets. However, mutations of PTEN or PIK3CA were not associated with the same expression profile or aggressive phenotype. STMN1 expression had independent prognostic value. The results affirm the utility of systematic characterization of the cancer genome in clinically annotated specimens and suggest the particular importance of the PI3K pathway in patients who have aggressive endometrial cancer.", "title": "Integrated genomic profiling of endometrial carcinoma associates aggressive tumors with indicators of PI3 kinase activation." }, { "docid": "24917562", "text": "PURPOSE To determine whether an increased resting energy expenditure (REE) and weight loss in lung cancer patients are related to a systemic inflammatory response. MATERIALS AND METHODS REE was measured by indirect calorimetry using a ventilated hood system. Soluble tumor necrosis factor receptor 55 (sTNF-R55) and sTNF-R75, soluble intercellular adhesion molecule (sICAM)-1, soluble E (sE)-selectin, lipopolysaccharide (LPS)-binding protein (LBP), interleukin (IL)-6, and TNF-alpha were measured using sandwich enzyme-linked immunosorbent assay (ELISA), and C-reactive protein (CRP) was measured by turbidimetry. A cross-sectional study was performed to compare inflammatory mediators between hypermetabolic (REE/Harris Benedict [HB] equation > or = 110%) versus normometabolic (REE/HB < 110%) patients and between patients who lost weight (more than 10% loss of preillness weight) versus those whose weight remained stable. \n RESULTS Eighty-seven patients with primary non-small-cell lung cancer were consecutively entered onto the study. Mean REE expressed as a percentage of the HB reference values was 118% +/- 12%; 67 patients were considered hypermetabolic. Twenty-six patients had a substantial loss of more than 10% of their preillness weight. Hypermetabolic patients were found to have significantly increased levels of sTNF-R55, sE-selectin, LBP, and CRP compared with normometabolic patients. Weight loss was related with increased levels of the sTNF-Rs, sICAM-1, IL-6, LBP, and CRP. \n CONCLUSION Hypermetabolism and weight loss are related to the presence of a systemic inflammatory response as reflected by enhanced levels of inflammatory mediators and acute phase proteins in patients with primary non-small-cell lung cancer.", "title": "Increased resting energy expenditure and weight loss are related to a systemic inflammatory response in lung cancer patients." }, { "docid": "29366489", "text": "Deleted in liver cancer 1 (DLC-1), as its name implied, was originally isolated as a potential tumor suppressor gene often deleted in hepatocellular carcinoma. Further studies have indicated that down-expression of DLC-1 either by genomic deletion or DNA methylation is associated with a variety of cancer types including lung, breast, prostate, kidney, colon, uterus, ovary, and stomach. Re-expression of DLC-1 in cancer cells regulates the structure of actin cytoskeleton and focal adhesions and significantly inhibits cell growth, supporting its role as a tumor suppressor. This tumor suppressive function relies on DLC-1's RhoGTPase activating protein (RhoGAP) activity and steroidogenic acute regulatory (StAR)-related lipid transfer (START) domain, as well as its focal adhesion localization, which is recruited by the Src Homology 2 (SH2) domains of tensins in a phosphotyrosine-independent fashion. Therefore, the expression and subcellular localization of DLC-1 could be a useful molecular marker for cancer prognosis, whereas DLC-1 and its downstream signaling molecules might be therapeutic targets for the treatment of cancer.", "title": "Deleted in liver cancer-1 (DLC-1): a tumor suppressor not just for liver." }, { "docid": "11615422", "text": "The search for target genes involved in unbalanced acquired chromosomal abnormalities has been largely unsuccessful, because the breakpoints of these rearrangements are too variable. Here, we use the example of dicentric chromosomes in B cell precursor acute lymphoblastic leukemia to show that, despite this heterogeneity, single genes are targeted through a variety of mechanisms. FISH showed that, although they were heterogeneous, breakpoints on 9p resulted in the partial or complete deletion of PAX5. Molecular copy number counting further delineated the breakpoints and facilitated cloning with long-distance inverse PCR. This approach identified 5 fusion gene partners with PAX5: LOC392027 (7p12.1), SLCO1B3 (12p12), ASXL1 (20q11.1), KIF3B (20q11.21), and C20orf112 (20q11.1). In each predicted fusion protein, the DNA-binding paired domain of PAX5 was present. Using quantitative PCR, we demonstrated that both the deletion and gene fusion events resulted in the same underexpression of PAX5, which extended to the differential expression of the PAX5 target genes, EBF1, ALDH1A1, ATP9A, and FLT3. Further molecular analysis showed deletion and mutation of the homologous PAX5 allele, providing further support for the key role of PAX5. Here, we show that specific gene loci may be the target of heterogeneous translocation breakpoints in human cancer, acting through a variety of mechanisms. This approach indicates an application for the identification of cancer genes in solid tumours, where unbalanced chromosomal rearrangements are particularly prevalent and few genes have been identified. It can be extrapolated that this strategy will reveal that the same mechanisms operate in cancer pathogenesis in general.", "title": "Variable breakpoints target PAX5 in patients with dicentric chromosomes: a model for the basis of unbalanced translocations in cancer." }, { "docid": "10145528", "text": "ATM, the gene that is mutated in ataxia-telangiectasia, is associated with cerebellar degeneration, abnormal proliferation of small blood vessels, and cancer. These clinically important manifestations have stimulated interest in defining the sequence variation in the ATM gene. Therefore, we undertook a comprehensive survey of sequence variation in ATM in diverse human populations. The protein-encoding exons of the gene (9,168 bp) and the adjacent intron and untranslated sequences (14,661 bp) were analyzed in 93 individuals from seven major human populations. In addition, the coding sequence was analyzed in one chimpanzee, one gorilla, one orangutan, and one Old World monkey. In human ATM, 88 variant sites were discovered by denaturing high-performance liquid chromatography, which is 96%-100% sensitive for detection of DNA sequence variation. ATM was compared to 14 other autosomal genes for nucleotide diversity. The noncoding regions of ATM had diversity values comparable to other genes, but the coding regions had very low diversity, especially in the last 29% of the protein sequence. A test of the neutral evolution hypothesis, through use of the Hudson/Kreitman/Aguadé statistic, revealed that this region of the human ATM gene was significantly constrained relative to that of the orangutan, the Old World monkey, and the mouse, but not relative to that of the chimpanzee or the gorilla. ATM displayed extensive linkage disequilibrium, consistent with suppression of meiotic recombination at this locus. Seven haplotypes were defined. Two haplotypes accounted for 82% of all chromosomes analyzed in all major populations; two others carrying the same D126E missense polymorphism accounted for 33% of chromosomes in Africa but were never observed outside of Africa. The high frequency of this polymorphism may be due either to a population expansion within Africa or to selective pressure.", "title": "Global analysis of ATM polymorphism reveals significant functional constraint." }, { "docid": "1617327", "text": "Mesenchymal cells contribute to the 'stroma' of most normal and malignant tissues, with specific mesenchymal cells participating in the regulatory niches of stem cells. By examining how mesenchymal osteolineage cells modulate haematopoiesis, here we show that deletion of Dicer1 specifically in mouse osteoprogenitors, but not in mature osteoblasts, disrupts the integrity of haematopoiesis. Myelodysplasia resulted and acute myelogenous leukaemia emerged that had acquired several genetic abnormalities while having intact Dicer1. Examining gene expression altered in osteoprogenitors as a result of Dicer1 deletion showed reduced expression of Sbds, the gene mutated in Schwachman-Bodian-Diamond syndrome-a human bone marrow failure and leukaemia pre-disposition condition. Deletion of Sbds in mouse osteoprogenitors induced bone marrow dysfunction with myelodysplasia. Therefore, perturbation of specific mesenchymal subsets of stromal cells can disorder differentiation, proliferation and apoptosis of heterologous cells, and disrupt tissue homeostasis. Furthermore, primary stromal dysfunction can result in secondary neoplastic disease, supporting the concept of niche-induced oncogenesis.", "title": "Bone progenitor dysfunction induces myelodysplasia and secondary leukemia" }, { "docid": "5409325", "text": "Pituitary gonadotropins follicle-stimulating hormone and luteinizing hormone are heterodimeric glycoproteins expressed in gonadotropes. They act on gonads and promote their development and functions including steroidogenesis and gametogenesis. Although transcriptional regulation of gonadotropin subunits has been well studied, the post-transcriptional regulation of gonadotropin subunits is not well understood. To test if microRNAs regulate the hormone-specific gonadotropin β subunits in vivo, we deleted Dicer in gonadotropes by a Cre-lox genetic approach. We found that many of the DICER-dependent microRNAs, predicted in silico to bind gonadotropin β subunit mRNAs, were suppressed in purified gonadotropes of mutant mice. Loss of DICER-dependent microRNAs in gonadotropes resulted in profound suppression of gonadotropin-β subunit proteins and, consequently, the heterodimeric hormone secretion. In addition to suppression of basal levels, interestingly, the post-gonadectomy-induced rise in pituitary gonadotropin synthesis and secretion were both abolished in mutants, indicating a defective gonadal negative feedback control. Furthermore, mutants lacking Dicer in gonadotropes displayed severely reduced fertility and were rescued with exogenous hormones confirming that the fertility defects were secondary to suppressed gonadotropins. Our studies reveal that DICER-dependent microRNAs are essential for gonadotropin homeostasis and fertility in mice. Our studies also implicate microRNAs in gonadal feedback control of gonadotropin synthesis and secretion. Thus, DICER-dependent microRNAs confer a new layer of transcriptional and post-transcriptional regulation in gonadotropes to orchestrate the hypothalamus-pituitary-gonadal axis physiology.", "title": "Gonadotrope-specific deletion of Dicer results in severely suppressed gonadotropins and fertility defects." }, { "docid": "36904081", "text": "The yeast ribosomal protein gene RPL32 of Saccharomyces cerevisiae is of particular interest for two reasons: 1) it is adjacent to another ribosomal protein gene, RP29, whose divergent transcription may be driven from the same control sequences, and 2) it appears that the splicing of its transcript is regulated by the product of the gene, ribosomal protein in L32. RPL32 has been analyzed in detail. It is essential for cell growth. Its sequence predicts L32 to be a protein of 105 amino acids, somewhat basic near the NH2 terminus, rather acidic near the COOH terminus, and homologous to ribosomal protein L30 of mammals. The reading frame has been confirmed by partial NH2-terminal analysis of L32. The nucleotide sequence also predicts an intron of 230 nucleotides, which begins with the unusual sequence GTCAGT and ends 40 nucleotides downstream of the consensus sequence TAC-TAAC. The intron has been confirmed by determination of the sequence of a cDNA clone. Transcription initiates 58 nucleotides upstream of the AUG initiation codon, and the polyadenylation site occurs 100 nucleotides downstream of the termination codon. Regulation of the transcription of ribosomal protein genes has been linked to two related consensus sequences. Analysis of the intergenic region between RP29 and RPL32 reveals three copies of these sequences. A deletion removing all three sequences reduces synthesis of a L32-LacZ fusion protein by more than 90%. Some residual activity, however, remains.", "title": "The yeast ribosomal protein L32 and its gene." }, { "docid": "5572127", "text": "The role of ataxia telangiectasia mutated (ATM), a DNA double-strand break recognition and response protein, in inflammation and inflammatory diseases is unclear. We have previously shown that high levels of systemic DNA damage are induced by intestinal inflammation in wild-type mice. To determine the effect of Atm deficiency in inflammation, we induced experimental colitis in Atm(-/-), Atm(+/-), and wild-type mice via dextran sulfate sodium (DSS) administration. Atm(-/-) mice had higher disease activity indices and rates of mortality compared with heterozygous and wild-type mice. Systemic DNA damage and immune response were characterized in peripheral blood throughout and after three cycles of treatment. Atm(-/-) mice showed increased sensitivity to levels of DNA strand breaks in peripheral leukocytes, as well as micronucleus formation in erythroblasts, compared with heterozygous and wild-type mice, especially during remission periods and after the end of treatment. Markers of reactive oxygen and nitrogen species-mediated damage, including 8-oxoguanine and nitrotyrosine, were present both in the distal colon and in peripheral leukocytes, with Atm(-/-) mice manifesting more 8-oxoguanine formation than wild-type mice. Atm(-/-) mice showed greater upregulation of inflammatory cytokines and significantly higher percentages of activated CD69+ and CD44+ T cells in the peripheral blood throughout treatment. ATM, therefore, may be a critical immunoregulatory factor dampening the deleterious effects of chronic DSS-induced inflammation, necessary for systemic genomic stability and homeostasis of the gut epithelial barrier.", "title": "Atm-deficient mice exhibit increased sensitivity to dextran sulfate sodium-induced colitis characterized by elevated DNA damage and persistent immune activation." }, { "docid": "8385277", "text": "Fanconi anemia (FA) is a genetic condition associated with bone marrow (BM) failure, myelodysplasia (MDS), and acute myeloid leukemia (AML). We studied 57 FA patients with hypoplastic or aplastic anemia (n = 20), MDS (n = 18), AML (n = 11), or no BM abnormality (n = 8). BM samples were analyzed by karyotype, high-density DNA arrays with respect to paired fibroblasts, and by selected oncogene sequencing. A specific pattern of chromosomal abnormalities was found in MDS/AML, which included 1q+ (44.8%), 3q+ (41.4%), -7/7q (17.2%), and 11q- (13.8%). Moreover, cryptic RUNX1/AML1 lesions (translocations, deletions, or mutations) were observed for the first time in FA (20.7%). Rare mutations of NRAS, FLT3-ITD, MLL-PTD, ERG amplification, and ZFP36L2-PRDM16 translocation, but no TP53, TET2, CBL, NPM1, and CEBPα mutations were found. Frequent homozygosity regions were related not to somatic copy-neutral loss of heterozygosity but to consanguinity, suggesting that homologous recombination is not a common progression mechanism in FA. Importantly, the RUNX1 and other chromosomal/genomic lesions were found at the MDS/AML stages, except for 1q+, which was found at all stages. These data have implications for staging and therapeutic managing in FA patients, and also to analyze the mechanisms of clonal evolution and oncogenesis in a background of genomic instability and BM failure.", "title": "Myelodysplasia and leukemia of Fanconi anemia are associated with a specific pattern of genomic abnormalities that includes cryptic RUNX1/AML1 lesions." }, { "docid": "19912367", "text": "Age-related changes in the niche have long been postulated to impair the function of somatic stem cells. Here we demonstrate that the aged stem cell niche in skeletal muscle contains substantially reduced levels of fibronectin (FN), leading to detrimental consequences for the function and maintenance of muscle stem cells (MuSCs). Deletion of the gene encoding FN from young regenerating muscles replicates the aging phenotype and leads to a loss of MuSC numbers. By using an extracellular matrix (ECM) library screen and pathway profiling, we characterize FN as a preferred adhesion substrate for MuSCs and demonstrate that integrin-mediated signaling through focal adhesion kinase and the p38 mitogen-activated protein kinase pathway is strongly de-regulated in MuSCs from aged mice because of insufficient attachment to the niche. Reconstitution of FN levels in the aged niche remobilizes stem cells and restores youth-like muscle regeneration. Taken together, we identify the loss of stem cell adhesion to FN in the niche ECM as a previously unknown aging mechanism.", "title": "Loss of fibronectin from the aged stem cell niche affects the regenerative capacity of skeletal muscle in mice" }, { "docid": "7717468", "text": "Microbial survival in a host is usually dependent on the ability of a pathogen to undergo changes that promote escape from host defense mechanisms. The human-pathogenic fungus Cryptococcus neoformans undergoes phenotypic switching in vivo that promotes persistence in tissue. By microarray and real-time PCR analyses, the allergen 1 gene (ALL1) was found to be downregulated in the hypervirulent mucoid switch variant, both during logarithmic growth and during intracellular growth in macrophages. The ALL1 gene encodes a small cytoplasmic protein that is involved in capsule formation. Growth of an all1Delta gene deletion mutant was normal. Similar to cells of the mucoid switch variant, all1Delta cells produced a larger polysaccharide capsule than cells of the smooth parent and the complemented strain produced, and the enlarged capsule inhibited macrophage phagocytosis. The mutant exhibited a modest defect in capsule induction compared to all of the other variants. In animal models the phenotype of the all1Delta mutant mimicked the hypervirulent phenotype of the mucoid switch variant, which is characterized by decreased host survival and elevated intracranial pressure. Decreased survival is likely the result of both an ineffective cell-mediated immune response and impaired phagocytosis by macrophages. Consequently, we concluded that, unlike loss of most virulence-associated genes, where loss of gene function results in attenuated virulence, loss of the ALL1 gene enhances virulence by altering the host-pathogen interaction and thereby impairing clearance. Our data identified the first cryptococcal gene associated with elevated intracranial pressure and support the hypothesis that an environmental opportunistic pathogen has modified its virulence in vivo by epigenetic downregulation of gene function.", "title": "Loss of allergen 1 confers a hypervirulent phenotype that resembles mucoid switch variants of Cryptococcus neoformans." }, { "docid": "25827024", "text": "Deletion of copper-zinc superoxide dismutase (CuZnSOD) in Sod1(-/-) mice leads to accelerated loss of muscle mass and force during aging, but the losses do not occur with muscle-specific deletion of CuZnSOD. To determine the role of motor neurons in the muscle decline, we generated transgenic Sod1(-/-) mice in which CuZnSOD was expressed under control of the synapsin 1 promoter (SynTgSod1(-/-) mice). SynTgSod1(-/-) mice expressed CuZnSOD in brain, spinal cord, and peripheral nerve, but not in other tissues. Sciatic nerve CuZnSOD content in SynTgSod1(-/-) mice was ~20% that of control mice, but no reduction in muscle mass or isometric force was observed in SynTgSod1(-/-) mice compared with control animals, whereas muscles of age-matched Sod1(-/-) mice displayed 30-40% reductions in mass and force. In addition, increased oxidative damage and adaptations in stress responses observed in muscles of Sod1(-/-) mice were absent in SynTgSod1(-/-) mice, and degeneration of neuromuscular junction (NMJ) structure and function occurred in Sod1(-/-) mice but not in SynTgSod1(-/-) mice. Our data demonstrate that specific CuZnSOD expression in neurons is sufficient to preserve NMJ and skeletal muscle structure and function in Sod1(-/-) mice and suggest that redox homeostasis in motor neurons plays a key role in initiating sarcopenia during aging.", "title": "Neuron-specific expression of CuZnSOD prevents the loss of muscle mass and function that occurs in homozygous CuZnSOD-knockout mice." } ]

[ { "docid": "40349336", "text": "Developmental abnormalities, cancer, and premature aging each have been linked to defects in the DNA damage response (DDR). Mutations in the ATR checkpoint regulator cause developmental defects in mice (pregastrulation lethality) and humans (Seckel syndrome). Here we show that eliminating ATR in adult mice leads to defects in tissue homeostasis and the rapid appearance of age-related phenotypes, such as hair graying, alopecia, kyphosis, osteoporosis, thymic involution, fibrosis, and other abnormalities. Histological and genetic analyses indicate that ATR deletion causes acute cellular loss in tissues in which continuous cell proliferation is required for maintenance. Importantly, thymic involution, alopecia, and hair graying in ATR knockout mice were associated with dramatic reductions in tissue-specific stem and progenitor cells and exhaustion of tissue renewal and homeostatic capacity. In aggregate, these studies suggest that reduced regenerative capacity in adults via deletion of a developmentally essential DDR gene is sufficient to cause the premature appearance of age-related phenotypes.", "title": "Deletion of the developmentally essential gene ATR in adult mice leads to age-related phenotypes and stem cell loss." } ]

[ { "docid": "12909503", "text": "DNA damage encountered by DNA replication forks poses risks of genome destabilization, a precursor to carcinogenesis. Damage checkpoint systems cause cell cycle arrest, promote repair and induce programed cell death when damage is severe. Checkpoints are critical parts of the DNA damage response network that act to suppress cancer. DNA damage and perturbation of replication machinery causes replication stress, characterized by accumulation of single-stranded DNA bound by replication protein A (RPA), which triggers activation of ataxia telangiectasia and Rad3 related (ATR) and phosphorylation of the RPA32, subunit of RPA, leading to Chk1 activation and arrest. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) [a kinase related to ataxia telangiectasia mutated (ATM) and ATR] has well characterized roles in DNA double-strand break repair, but poorly understood roles in replication stress-induced RPA phosphorylation. We show that DNA-PKcs mutant cells fail to arrest replication following stress, and mutations in RPA32 phosphorylation sites targeted by DNA-PKcs increase the proportion of cells in mitosis, impair ATR signaling to Chk1 and confer a G2/M arrest defect. Inhibition of ATR and DNA-PK (but not ATM), mimic the defects observed in cells expressing mutant RPA32. Cells expressing mutant RPA32 or DNA-PKcs show sustained H2AX phosphorylation in response to replication stress that persists in cells entering mitosis, indicating inappropriate mitotic entry with unrepaired damage.", "title": "Distinct roles for DNA-PK, ATM and ATR in RPA phosphorylation and checkpoint activation in response to replication stress" }, { "docid": "14178995", "text": "The genetic diseases Hutchinson-Gilford progeria syndrome (HGPS) and restrictive dermopathy (RD) arise from accumulation of farnesylated prelamin A because of defects in the lamin A maturation pathway. Both of these diseases exhibit symptoms that can be viewed as accelerated aging. The mechanism by which accumulation of farnesylated prelamin A leads to these accelerated aging phenotypes is not understood. Here we present evidence that in HGPS and RD fibroblasts, DNA damage checkpoints are persistently activated because of the compromise in genomic integrity. Inactivation of checkpoint kinases Ataxia-telangiectasia-mutated (ATM) and ATR (ATM- and Rad3-related) in these patient cells can partially overcome their early replication arrest. Treatment of patient cells with a protein farnesyltransferase inhibitor (FTI) did not result in reduction of DNA double-strand breaks and damage checkpoint signaling, although the treatment significantly reversed the aberrant shape of their nuclei. This suggests that DNA damage accumulation and aberrant nuclear morphology are independent phenotypes arising from prelamin A accumulation in these progeroid syndromes. Since DNA damage accumulation is an important contributor to the symptoms of HGPS, our results call into question the possibility of treatment of HGPS with FTIs alone.", "title": "Summary" }, { "docid": "3113630", "text": "Ataxia telangiectasia is a neurodegenerative disease caused by mutation of the Atm gene. Here we report that ataxia telangiectasia mutated (ATM) deficiency causes nuclear accumulation of histone deacetylase 4 (HDAC4) in neurons and promotes neurodegeneration. Nuclear HDAC4 binds to chromatin, as well as to myocyte enhancer factor 2A (MEF2A) and cAMP-responsive element binding protein (CREB), leading to histone deacetylation and altered neuronal gene expression. Blocking either HDAC4 activity or its nuclear accumulation blunts these neurodegenerative changes and rescues several behavioral abnormalities of ATM-deficient mice. Full rescue of the neurodegeneration, however, also requires the presence of HDAC4 in the cytoplasm, suggesting that the ataxia telangiectasia phenotype results both from a loss of cytoplasmic HDAC4 as well as its nuclear accumulation. To remain cytoplasmic, HDAC4 must be phosphorylated. The activity of the HDAC4 phosphatase, protein phosphatase 2A (PP2A), is downregulated by ATM-mediated phosphorylation. In ATM deficiency, enhanced PP2A activity leads to HDAC4 dephosphorylation and the nuclear accumulation of HDAC4. Our results define a crucial role of the cellular localization of HDAC4 in the events leading to ataxia telangiectasia neurodegeneration.", "title": "Nuclear accumulation of HDAC4 in ATM deficiency promotes neurodegeneration in ataxia-telangiectasia" }, { "docid": "43192375", "text": "Adipose tissue macrophages (ATMs) infiltrate adipose tissue during obesity and contribute to insulin resistance. We hypothesized that macrophages migrating to adipose tissue upon high-fat feeding may differ from those that reside there under normal diet conditions. To this end, we found a novel F4/80(+)CD11c(+) population of ATMs in adipose tissue of obese mice that was not seen in lean mice. ATMs from lean mice expressed many genes characteristic of M2 or \"alternatively activated\" macrophages, including Ym1, arginase 1, and Il10. Diet-induced obesity decreased expression of these genes in ATMs while increasing expression of genes such as those encoding TNF-alpha and iNOS that are characteristic of M1 or \"classically activated\" macrophages. Interestingly, ATMs from obese C-C motif chemokine receptor 2-KO (Ccr2-KO) mice express M2 markers at levels similar to those from lean mice. The antiinflammatory cytokine IL-10, which was overexpressed in ATMs from lean mice, protected adipocytes from TNF-alpha-induced insulin resistance. Thus, diet-induced obesity leads to a shift in the activation state of ATMs from an M2-polarized state in lean animals that may protect adipocytes from inflammation to an M1 proinflammatory state that contributes to insulin resistance.", "title": "Obesity induces a phenotypic switch in adipose tissue macrophage polarization." }, { "docid": "19912367", "text": "Age-related changes in the niche have long been postulated to impair the function of somatic stem cells. Here we demonstrate that the aged stem cell niche in skeletal muscle contains substantially reduced levels of fibronectin (FN), leading to detrimental consequences for the function and maintenance of muscle stem cells (MuSCs). Deletion of the gene encoding FN from young regenerating muscles replicates the aging phenotype and leads to a loss of MuSC numbers. By using an extracellular matrix (ECM) library screen and pathway profiling, we characterize FN as a preferred adhesion substrate for MuSCs and demonstrate that integrin-mediated signaling through focal adhesion kinase and the p38 mitogen-activated protein kinase pathway is strongly de-regulated in MuSCs from aged mice because of insufficient attachment to the niche. Reconstitution of FN levels in the aged niche remobilizes stem cells and restores youth-like muscle regeneration. Taken together, we identify the loss of stem cell adhesion to FN in the niche ECM as a previously unknown aging mechanism.", "title": "Loss of fibronectin from the aged stem cell niche affects the regenerative capacity of skeletal muscle in mice" }, { "docid": "39225849", "text": "The Bloom syndrome helicase (BLM) is critical for genomic stability. A defect in BLM activity results in the cancer-predisposing Bloom syndrome (BS). Here, we report that BLM-deficient cell lines and primary fibroblasts display an endogenously activated DNA double-strand break checkpoint response with prominent levels of phosphorylated histone H2AX (gamma-H2AX), Chk2 (p(T68)Chk2), and ATM (p(S1981)ATM) colocalizing in nuclear foci. Interestingly, the mitotic fraction of gamma-H2AX foci did not seem to be higher in BLM-deficient cells, indicating that these lesions form transiently during interphase. Pulse labeling with iododeoxyuridine and immunofluorescence microscopy showed the colocalization of gamma-H2AX, ATM, and Chk2 together with replication foci. Those foci costained for Rad51, indicating homologous recombination at these replication sites. We therefore analyzed replication in BS cells using a single molecule approach on combed DNA fibers. In addition to a higher frequency of replication fork barriers, BS cells displayed a reduced average fork velocity and global reduction of interorigin distances indicative of an elevated frequency of origin firing. Because BS is one of the most penetrant cancer-predisposing hereditary diseases, it is likely that the lack of BLM engages the cells in a situation similar to precancerous tissues with replication stress. To our knowledge, this is the first report of high ATM-Chk2 kinase activation and its linkage to replication defects in a BS model.", "title": "Endogenous gamma-H2AX-ATM-Chk2 checkpoint activation in Bloom's syndrome helicase deficient cells is related to DNA replication arrested forks." }, { "docid": "25827024", "text": "Deletion of copper-zinc superoxide dismutase (CuZnSOD) in Sod1(-/-) mice leads to accelerated loss of muscle mass and force during aging, but the losses do not occur with muscle-specific deletion of CuZnSOD. To determine the role of motor neurons in the muscle decline, we generated transgenic Sod1(-/-) mice in which CuZnSOD was expressed under control of the synapsin 1 promoter (SynTgSod1(-/-) mice). SynTgSod1(-/-) mice expressed CuZnSOD in brain, spinal cord, and peripheral nerve, but not in other tissues. Sciatic nerve CuZnSOD content in SynTgSod1(-/-) mice was ~20% that of control mice, but no reduction in muscle mass or isometric force was observed in SynTgSod1(-/-) mice compared with control animals, whereas muscles of age-matched Sod1(-/-) mice displayed 30-40% reductions in mass and force. In addition, increased oxidative damage and adaptations in stress responses observed in muscles of Sod1(-/-) mice were absent in SynTgSod1(-/-) mice, and degeneration of neuromuscular junction (NMJ) structure and function occurred in Sod1(-/-) mice but not in SynTgSod1(-/-) mice. Our data demonstrate that specific CuZnSOD expression in neurons is sufficient to preserve NMJ and skeletal muscle structure and function in Sod1(-/-) mice and suggest that redox homeostasis in motor neurons plays a key role in initiating sarcopenia during aging.", "title": "Neuron-specific expression of CuZnSOD prevents the loss of muscle mass and function that occurs in homozygous CuZnSOD-knockout mice." }, { "docid": "30353437", "text": "Ataxia telangiectasia (AT) has long intrigued the biomedical research community owing to the spectrum of defects that are characteristic of the disease, including neurodegeneration, immune dysfunction, radiosensitivity and cancer predisposition. Following the identification of mutations in ATM (ataxia telangiectasia, mutated) as the underlying cause of the disease, biochemical analysis of this protein kinase has shown that it is a crucial nexus for the cellular response to DNA double-stranded breaks. Many ATM kinase substrates are important players in the cellular responses that prevent cancer. Accordingly, AT is a disease that results from defects in the response to specific types of DNA damage. Thus, although it is a rare neurodegenerative disease, understanding the biology of AT will lead to a greater understanding of the fundamental processes that underpin cancer and neurodegeneration.", "title": "ATM and ataxia telangiectasia." }, { "docid": "13791206", "text": "Defective DNA repair by homologous recombination (HR) is thought to be a major contributor to tumorigenesis in individuals carrying Brca1 mutations. Here, we show that DNA breaks in Brca1-deficient cells are aberrantly joined into complex chromosome rearrangements by a process dependent on the nonhomologous end-joining (NHEJ) factors 53BP1 and DNA ligase 4. Loss of 53BP1 alleviates hypersensitivity of Brca1 mutant cells to PARP inhibition and restores error-free repair by HR. Mechanistically, 53BP1 deletion promotes ATM-dependent processing of broken DNA ends to produce recombinogenic single-stranded DNA competent for HR. In contrast, Lig4 deficiency does not rescue the HR defect in Brca1 mutant cells but prevents the joining of chromatid breaks into chromosome rearrangements. Our results illustrate that HR and NHEJ compete to process DNA breaks that arise during DNA replication and that shifting the balance between these pathways can be exploited to selectively protect or kill cells harboring Brca1 mutations.", "title": "53BP1 Inhibits Homologous Recombination in Brca1-Deficient Cells by Blocking Resection of DNA Breaks" }, { "docid": "8083310", "text": "Impaired erythropoiesis in the deletion 5q (del(5q)) subtype of myelodysplastic syndrome (MDS) has been linked to heterozygous deletion of RPS14, which encodes the ribosomal protein small subunit 14. We generated mice with conditional inactivation of Rps14 and demonstrated an erythroid differentiation defect that is dependent on the tumor suppressor protein p53 (encoded by Trp53 in mice) and is characterized by apoptosis at the transition from polychromatic to orthochromatic erythroblasts. This defect resulted in age-dependent progressive anemia, megakaryocyte dysplasia and loss of hematopoietic stem cell (HSC) quiescence. As assessed by quantitative proteomics, mutant erythroblasts expressed higher levels of proteins involved in innate immune signaling, notably the heterodimeric S100 calcium-binding proteins S100a8 and S100a9. S100a8—whose expression was increased in mutant erythroblasts, monocytes and macrophages—is functionally involved in the erythroid defect caused by the Rps14 deletion, as addition of recombinant S100a8 was sufficient to induce a differentiation defect in wild-type erythroid cells, and genetic inactivation of S100a8 expression rescued the erythroid differentiation defect of Rps14-haploinsufficient HSCs. Our data link Rps14 haploinsufficiency in del(5q) MDS to activation of the innate immune system and induction of S100A8-S100A9 expression, leading to a p53-dependent erythroid differentiation defect.", "title": "Rps14 haploinsufficiency causes a block in erythroid differentiation mediated by S100A8 and S100A9" }, { "docid": "24917562", "text": "PURPOSE To determine whether an increased resting energy expenditure (REE) and weight loss in lung cancer patients are related to a systemic inflammatory response. MATERIALS AND METHODS REE was measured by indirect calorimetry using a ventilated hood system. Soluble tumor necrosis factor receptor 55 (sTNF-R55) and sTNF-R75, soluble intercellular adhesion molecule (sICAM)-1, soluble E (sE)-selectin, lipopolysaccharide (LPS)-binding protein (LBP), interleukin (IL)-6, and TNF-alpha were measured using sandwich enzyme-linked immunosorbent assay (ELISA), and C-reactive protein (CRP) was measured by turbidimetry. A cross-sectional study was performed to compare inflammatory mediators between hypermetabolic (REE/Harris Benedict [HB] equation > or = 110%) versus normometabolic (REE/HB < 110%) patients and between patients who lost weight (more than 10% loss of preillness weight) versus those whose weight remained stable. \n RESULTS Eighty-seven patients with primary non-small-cell lung cancer were consecutively entered onto the study. Mean REE expressed as a percentage of the HB reference values was 118% +/- 12%; 67 patients were considered hypermetabolic. Twenty-six patients had a substantial loss of more than 10% of their preillness weight. Hypermetabolic patients were found to have significantly increased levels of sTNF-R55, sE-selectin, LBP, and CRP compared with normometabolic patients. Weight loss was related with increased levels of the sTNF-Rs, sICAM-1, IL-6, LBP, and CRP. \n CONCLUSION Hypermetabolism and weight loss are related to the presence of a systemic inflammatory response as reflected by enhanced levels of inflammatory mediators and acute phase proteins in patients with primary non-small-cell lung cancer.", "title": "Increased resting energy expenditure and weight loss are related to a systemic inflammatory response in lung cancer patients." }, { "docid": "29366489", "text": "Deleted in liver cancer 1 (DLC-1), as its name implied, was originally isolated as a potential tumor suppressor gene often deleted in hepatocellular carcinoma. Further studies have indicated that down-expression of DLC-1 either by genomic deletion or DNA methylation is associated with a variety of cancer types including lung, breast, prostate, kidney, colon, uterus, ovary, and stomach. Re-expression of DLC-1 in cancer cells regulates the structure of actin cytoskeleton and focal adhesions and significantly inhibits cell growth, supporting its role as a tumor suppressor. This tumor suppressive function relies on DLC-1's RhoGTPase activating protein (RhoGAP) activity and steroidogenic acute regulatory (StAR)-related lipid transfer (START) domain, as well as its focal adhesion localization, which is recruited by the Src Homology 2 (SH2) domains of tensins in a phosphotyrosine-independent fashion. Therefore, the expression and subcellular localization of DLC-1 could be a useful molecular marker for cancer prognosis, whereas DLC-1 and its downstream signaling molecules might be therapeutic targets for the treatment of cancer.", "title": "Deleted in liver cancer-1 (DLC-1): a tumor suppressor not just for liver." }, { "docid": "4323449", "text": "More than forty per cent of the mammalian genome is derived from retroelements, of which about one-quarter are endogenous retroviruses (ERVs). Some are still active, notably in mice the highly polymorphic early transposon (ETn)/MusD and intracisternal A-type particles (IAP). ERVs are transcriptionally silenced during early embryogenesis by histone and DNA methylation (and reviewed in ref. 7), although the initiators of this process, which is essential to protect genome integrity, remain largely unknown. KAP1 (KRAB-associated protein 1, also known as tripartite motif-containing protein 28, TRIM28) represses genes by recruiting the histone methyltransferase SETDB1, heterochromatin protein 1 (HP1) and the NuRD histone deacetylase complex, but few of its physiological targets are known. Two lines of evidence suggest that KAP1-mediated repression could contribute to the control of ERVs: first, KAP1 can trigger permanent gene silencing during early embryogenesis, and second, a KAP1 complex silences the retrovirus murine leukaemia virus in embryonic cells. Consistent with this hypothesis, here we show that KAP1 deletion leads to a marked upregulation of a range of ERVs, in particular IAP elements, in mouse embryonic stem (ES) cells and in early embryos. We further demonstrate that KAP1 acts synergistically with DNA methylation to silence IAP elements, and that it is enriched at the 5′ untranslated region (5′UTR) of IAP genomes, where KAP1 deletion leads to the loss of histone 3 lysine 9 trimethylation (H3K9me3), a hallmark of KAP1-mediated repression. Correspondingly, IAP 5′UTR sequences can impose in cis KAP1-dependent repression on a heterologous promoter in ES cells. Our results establish that KAP1 controls endogenous retroelements during early embryonic development.", "title": "KAP1 controls endogenous retroviruses in embryonic stem cells" }, { "docid": "39559521", "text": "The negative selection of self-reactive thymocytes depends on the expression of tissue-specific antigens by medullary thymic epithelial cells. The autoimmune regulator (Aire) protein plays an important role in turning on these antigens, and the absence of even one Aire-induced tissue-specific antigen in the thymus can lead to autoimmunity in the antigen-expressing target organ. Recently, Aire protein has been detected in peripheral lymphoid organs, suggesting that peripheral Aire plays a complementary role here. In these peripheral sites, Aire was found to regulate the expression of a group of tissue-specific antigens that is distinct from those expressed in the thymus. Furthermore, transgenic antigen expression in extrathymic Aire-expressing cells (eTACs) can mediate deletional tolerance, but the immunological relevance of Aire-dependent, endogenous tissue-specific antigens remains to be determined.", "title": "Control of central and peripheral tolerance by Aire." }, { "docid": "8247597", "text": "Mutations and deletions in the mitochondrial genome (mtDNA), as well as instability of the nuclear genome, are involved in multiple human diseases. Here, we report that in Saccharomyces cerevisiae, loss of mtDNA leads to nuclear genome instability, through a process of cell-cycle arrest and selection we define as a cellular crisis. This crisis is not mediated by the absence of respiration, but instead correlates with a reduction in the mitochondrial membrane potential. Analysis of cells undergoing this crisis identified a defect in iron-sulfur cluster (ISC) biogenesis, which requires normal mitochondrial function. We found that downregulation of nonmitochondrial ISC protein biogenesis was sufficient to cause increased genomic instability in cells with intact mitochondrial function. These results suggest mitochondrial dysfunction stimulates nuclear genome instability by inhibiting the production of ISC-containing protein(s), which are required for maintenance of nuclear genome integrity. For a video summary of this article, see the PaperFlick file available with the online Supplemental Data.", "title": "Mitochondrial Dysfunction Leads to Nuclear Genome Instability via an Iron-Sulfur Cluster Defect" }, { "docid": "10145528", "text": "ATM, the gene that is mutated in ataxia-telangiectasia, is associated with cerebellar degeneration, abnormal proliferation of small blood vessels, and cancer. These clinically important manifestations have stimulated interest in defining the sequence variation in the ATM gene. Therefore, we undertook a comprehensive survey of sequence variation in ATM in diverse human populations. The protein-encoding exons of the gene (9,168 bp) and the adjacent intron and untranslated sequences (14,661 bp) were analyzed in 93 individuals from seven major human populations. In addition, the coding sequence was analyzed in one chimpanzee, one gorilla, one orangutan, and one Old World monkey. In human ATM, 88 variant sites were discovered by denaturing high-performance liquid chromatography, which is 96%-100% sensitive for detection of DNA sequence variation. ATM was compared to 14 other autosomal genes for nucleotide diversity. The noncoding regions of ATM had diversity values comparable to other genes, but the coding regions had very low diversity, especially in the last 29% of the protein sequence. A test of the neutral evolution hypothesis, through use of the Hudson/Kreitman/Aguadé statistic, revealed that this region of the human ATM gene was significantly constrained relative to that of the orangutan, the Old World monkey, and the mouse, but not relative to that of the chimpanzee or the gorilla. ATM displayed extensive linkage disequilibrium, consistent with suppression of meiotic recombination at this locus. Seven haplotypes were defined. Two haplotypes accounted for 82% of all chromosomes analyzed in all major populations; two others carrying the same D126E missense polymorphism accounted for 33% of chromosomes in Africa but were never observed outside of Africa. The high frequency of this polymorphism may be due either to a population expansion within Africa or to selective pressure.", "title": "Global analysis of ATM polymorphism reveals significant functional constraint." }, { "docid": "1617327", "text": "Mesenchymal cells contribute to the 'stroma' of most normal and malignant tissues, with specific mesenchymal cells participating in the regulatory niches of stem cells. By examining how mesenchymal osteolineage cells modulate haematopoiesis, here we show that deletion of Dicer1 specifically in mouse osteoprogenitors, but not in mature osteoblasts, disrupts the integrity of haematopoiesis. Myelodysplasia resulted and acute myelogenous leukaemia emerged that had acquired several genetic abnormalities while having intact Dicer1. Examining gene expression altered in osteoprogenitors as a result of Dicer1 deletion showed reduced expression of Sbds, the gene mutated in Schwachman-Bodian-Diamond syndrome-a human bone marrow failure and leukaemia pre-disposition condition. Deletion of Sbds in mouse osteoprogenitors induced bone marrow dysfunction with myelodysplasia. Therefore, perturbation of specific mesenchymal subsets of stromal cells can disorder differentiation, proliferation and apoptosis of heterologous cells, and disrupt tissue homeostasis. Furthermore, primary stromal dysfunction can result in secondary neoplastic disease, supporting the concept of niche-induced oncogenesis.", "title": "Bone progenitor dysfunction induces myelodysplasia and secondary leukemia" }, { "docid": "4422868", "text": "Intestinal cancer is initiated by Wnt-pathway-activating mutations in genes such as adenomatous polyposis coli (APC). As in most cancers, the cell of origin has remained elusive. In a previously established Lgr5 (leucine-rich-repeat containing G-protein-coupled receptor 5) knockin mouse model, a tamoxifen-inducible Cre recombinase is expressed in long-lived intestinal stem cells. Here we show that deletion of Apc in these stem cells leads to their transformation within days. Transformed stem cells remain located at crypt bottoms, while fuelling a growing microadenoma. These microadenomas show unimpeded growth and develop into macroscopic adenomas within 3-5weeks. The distribution of Lgr5+ cells within stem-cell-derived adenomas indicates that a stem cell/progenitor cell hierarchy is maintained in early neoplastic lesions. When Apc is deleted in short-lived transit-amplifying cells using a different cre mouse, the growth of the induced microadenomas rapidly stalls. Even after 30weeks, large adenomas are very rare in these mice. We conclude that stem-cell-specific loss of Apc results in progressively growing neoplasia.", "title": "Crypt stem cells as the cells-of-origin of intestinal cancer" }, { "docid": "5573975", "text": "Molecules associated with the transforming growth factor β (TGF-β) superfamily, such as bone morphogenic proteins (BMPs) and TGF-β, are key regulators of inflammation, apoptosis and cellular transitions. Here we show that the BMP receptor activin-like kinase 3 (Alk3) is elevated early in diseased kidneys after injury. We also found that its deletion in the tubular epithelium leads to enhanced TGF-β1-Smad family member 3 (Smad3) signaling, epithelial damage and fibrosis, suggesting a protective role for Alk3-mediated signaling in the kidney. A structure-function analysis of the BMP-Alk3-BMP receptor, type 2 (BMPR2) ligand-receptor complex, along with synthetic organic chemistry, led us to construct a library of small peptide agonists of BMP signaling that function through the Alk3 receptor. One such peptide agonist, THR-123, suppressed inflammation, apoptosis and the epithelial-to-mesenchymal transition program and reversed established fibrosis in five mouse models of acute and chronic renal injury. THR-123 acts specifically through Alk3 signaling, as mice with a targeted deletion for Alk3 in their tubular epithelium did not respond to therapy with THR-123. Combining THR-123 and the angiotensin-converting enzyme inhibitor captopril had an additive therapeutic benefit in controlling renal fibrosis. Our studies show that BMP signaling agonists constitute a new line of therapeutic agents with potential utility in the clinic to induce regeneration, repair and reverse established fibrosis.", "title": "Activin–like kinase–3 activity is important for kidney regeneration and reversal of fibrosis" } ]

[ { "docid": "9505448", "text": "Activation of the mammalian Notch receptor after ligand binding relies on a succession of events including metalloprotease-cleavage, endocytosis, monoubiquitination, and eventually processing by the gamma-secretase, giving rise to a soluble, transcriptionally active molecule. The Notch1 receptor was proposed to be monoubiquitinated before its gamma-secretase cleavage; the targeted lysine has been localized to its submembrane domain. Investigating how this step might be regulated by a deubiquitinase (DUB) activity will provide new insight for understanding Notch receptor activation and downstream signaling. An immunofluorescence-based screening of an shRNA library allowed us to identify eIF3f, previously known as one of the subunits of the translation initiation factor eIF3, as a DUB targeting the activated Notch receptor. We show that eIF3f has an intrinsic DUB activity. Knocking down eIF3f leads to an accumulation of monoubiquitinated forms of activated Notch, an effect counteracted by murine WT eIF3f but not by a catalytically inactive mutant. We also show that eIF3f is recruited to activated Notch on endocytic vesicles by the putative E3 ubiquitin ligase Deltex1, which serves as a bridging factor. Finally, catalytically inactive forms of eIF3f as well as shRNAs targeting eIF3f repress Notch activation in a coculture assay, showing that eIF3f is a new positive regulator of the Notch pathway. Our results support two new and provocative conclusions: (1) The activated form of Notch needs to be deubiquitinated before being processed by the gamma-secretase activity and entering the nucleus, where it fulfills its transcriptional function. (2) The enzyme accounting for this deubiquitinase activity is eIF3f, known so far as a translation initiation factor. These data improve our knowledge of Notch signaling but also open new avenues of research on the Zomes family and the translation initiation factors.", "title": "The Translation Initiation Factor 3f (eIF3f) Exhibits a Deubiquitinase Activity Regulating Notch Activation" } ]

[ { "docid": "25942757", "text": "The substantial importance of P-selectin glycoprotein ligand 1 (PSGL-1) in leukocyte trafficking has continued to emerge beyond its initial identification as a selectin ligand. PSGL-1 seemed to be a relatively simple molecule with an extracellular mucin domain extended as a flexible rod, teleologically consistent with its primary role in tethering leukocytes to endothelial selectins. The rolling interaction between leukocyte and endothelium mediated by this selectin-PSGL-1 interaction requires branched O-glycan extensions on specific PSGL-1 amino acid residues. In some cells, such as neutrophils, the glycosyltransferases involved in formation of the O-glycans are constitutively expressed, while in other cells, such as T cells, they are expressed only after appropriate activation. Thus, PSGL-1 supports leukocyte recruitment in both innate and adaptive arms of the immune response. A complex array of amino acids within the selectins engage multiple sugar residues of the branched O-glycans on PSGL-1 and provide the molecular interactions responsible for the velcro-like catch bonds that support leukocyte rolling. Such binding of PSGL-1 can also induce signaling events that influence cell phenotype and function. Scrutiny of PSGL-1 has revealed a better understanding of how it performs as a selectin ligand and yielded unexpected insights that extend its scope from supporting leukocyte rolling in inflammatory settings to homeostasis including stem cell homing to the thymus and mature T-cell homing to secondary lymphoid organs. PSGL-1 has been found to bind homeostatic chemokines CCL19 and CCL21 and to support the chemotactic response to these chemokines. Surprisingly, the O-glycan modifications of PSGL-1 that support rolling mediated by selectins in inflammatory conditions interfere with PSGL-1 binding to homeostatic chemokines and thereby limit responsiveness to the chemotactic cues used in steady state T-cell traffic. The multi-level influence of PSGL-1 on cell traffic in both inflammatory and steady state settings is therefore substantially determined by the orchestrated addition of O-glycans. However, central as specific O-glycosylation is to PSGL-1 function, in vivo regulation of PSGL-1 glycosylation in T cells remains poorly understood. It is our purpose herein to review what is known, and not known, of PSGL-1 glycosylation and to update understanding of PSGL-1 functional scope.", "title": "PSGL-1 function in immunity and steady state homeostasis." }, { "docid": "140874", "text": "It is thought that the H19 imprinting control region (ICR) directs the silencing of the maternally inherited Igf2 allele through a CTCF-dependent chromatin insulator. The ICR has been shown to interact physically with a silencer region in Igf2, differentially methylated region (DMR)1, but the role of CTCF in this chromatin loop and whether it restricts the physical access of distal enhancers to Igf2 is not known. We performed systematic chromosome conformation capture analyses in the Igf2/H19 region over >160 kb, identifying sequences that interact physically with the distal enhancers and the ICR. We found that, on the paternal chromosome, enhancers interact with the Igf2 promoters but that, on the maternal allele, this is prevented by CTCF binding within the H19 ICR. CTCF binding in the maternal ICR regulates its interaction with matrix attachment region (MAR)3 and DMR1 at Igf2, thus forming a tight loop around the maternal Igf2 locus, which may contribute to its silencing. Mutation of CTCF binding sites in the H19 ICR leads to loss of CTCF binding and de novo methylation of a CTCF target site within Igf2 DMR1, showing that CTCF can coordinate regional epigenetic marks. This systematic chromosome conformation capture analysis of an imprinting cluster reveals that CTCF has a critical role in the epigenetic regulation of higher-order chromatin structure and gene silencing over considerable distances in the genome.", "title": "CTCF binding at the H19 imprinting control region mediates maternally inherited higher-order chromatin conformation to restrict enhancer access to Igf2." }, { "docid": "207972", "text": "Early region 3 (E3) of group C human adenoviruses (Ad) encodes several inhibitors of tumor necrosis factor alpha (TNF-alpha) cytolysis, including an E3 14.7-kDa protein (E3-14.7K) and a heterodimer containing two polypeptides of 10.4 and 14.5 kDa. To understand the mechanism by which the viral proteins inhibit TNF-alpha functions, the E3-14.7K protein was used to screen a HeLa cell cDNA library to search for interacting proteins in the yeast two-hybrid system. A novel protein containing multiple leucine zipper domains without any significant homology with any known protein was identified and has been named FIP-2 (for 14.7K-interacting protein). FIP-2 interacted with E3-14.7K both in vitro and in vivo. It colocalized with Ad E3-14.7K in the cytoplasm, especially near the nuclear membrane, and caused redistribution of the viral protein. FIP-2 by itself does not cause cell death; however, it can reverse the protective effect of E3-14.7K on cell killing induced by overexpression of the intracellular domain of the 55-kDa TNF receptor or by RIP, a death protein involved in the TNF-alpha and Fas apoptosis pathways. Deletion analysis indicates that the reversal effect of FIP-2 depends on its interaction with E3-14.7K. Three major mRNA forms of FIP-2 have been detected in multiple human tissues, and expression of the transcripts was induced by TNF-alpha treatment in a time-dependent manner in two different cell lines. FIP-2 has consensus sequences for several potential posttranslational modifications. These data suggest that FIP-2 is one of the cellular targets for Ad E3-14.7K and that its mechanism of affecting cell death involves the TNF receptor, RIP, or a downstream molecule affected by either of these two molecules.", "title": "Interaction of an adenovirus E3 14.7-kilodalton protein with a novel tumor necrosis factor alpha-inducible cellular protein containing leucine zipper domains." }, { "docid": "21943141", "text": "The recent discovery of a ubiquitous translocation pathway, specifically required for proteins with a twin-arginine motif in their signal peptide, has focused interest on its membrane-bound components, one of which is known as TatC. Unlike most organisms of which the genome has been sequenced completely, the Gram-positive eubacterium Bacillus subtilis contains two tatC-like genes denoted tatCd and tatCy. The corresponding TatCd and TatCy proteins have the potential to be involved in the translocation of 27 proteins with putative twin-arginine signal peptides of which approximately 6-14 are likely to be secreted into the growth medium. Using a proteomic approach, we show that PhoD of B. subtilis, a phosphodiesterase belonging to a novel protein family of which all known members are synthesized with typical twin-arginine signal peptides, is secreted via the twin-arginine translocation pathway. Strikingly, TatCd is of major importance for the secretion of PhoD, whereas TatCy is not required for this process. Thus, TatC appears to be a specificity determinant for protein secretion via the Tat pathway. Based on our observations, we hypothesize that the TatC-determined pathway specificity is based on specific interactions between TatC-like proteins and other pathway components, such as TatA, of which three paralogues are present in B. subtilis.", "title": "TatC is a specificity determinant for protein secretion via the twin-arginine translocation pathway." }, { "docid": "10937190", "text": "The morphogenesis of the C. elegans embryo is largely controlled by the development of the epidermis, also known as the hypodermis, a single epithelial layer that surrounds the animal. Morphogenesis of the epidermis involves cell-cell interactions with internal tissues, such as the developing nervous system and musculature. Genetic analysis of mutants with aberrant epidermal morphology has defined multiple steps in epidermal morphogenesis. In the wild type, epidermal cells are generated on the dorsal side of the embryo among the progeny of four early embryonic blastomeres. Specification of epidermal fate is regulated by a hierarchy of transcription factors. After specification, dorsal epidermal cells rearrange, a process known as dorsal intercalation. Most epidermal cells fuse to generate multinucleate syncytia. The dorsally located epidermal sheet undergoes epiboly to enclose the rest of the embryo in a process known as ventral enclosure; this movement requires both an intact epidermal layer and substrate neuroblasts. At least three distinct types of cellular behavior underlie the enclosure of different regions of the epidermis. Following enclosure, the epidermis elongates, a process driven by coordinated cell shape changes. Epidermal actin microfilaments, microtubules, and intermediate filaments all play roles in elongation, as do body wall muscles. The final shape of the epidermis is maintained by the collagenous exoskeleton, secreted by the apical surface of the epidermis.", "title": "Table of Contents" }, { "docid": "42314147", "text": "Sp1-like proteins are characterized by three conserved C-terminal zinc finger motifs that bind GC-rich sequences found in promoters of numerous genes essential for mammalian cell homeostasis. These proteins behave as transcriptional activators or repressors. Although significant information has been reported on the molecular mechanisms by which Sp1-like activators function, relatively little is known about mechanisms for repressor proteins. Here we report the functional characterization of BTEB3, a ubiquitously expressed Sp1-like transcriptional repressor. GAL4 assays show that the N terminus of BTEB3 contains regions that can act as direct repressor domains. Immunoprecipitation assays reveal that BTEB3 interacts with the co-repressor mSin3A and the histone deacetylase protein HDAC-1. Gel shift assays demonstrate that BTEB3 specifically binds the BTE site, a well characterized GC-rich DNA element, with an affinity similar to that of Sp1. Reporter and gel shift assays in Chinese hamster ovary cells show that BTEB3 can also mediate repression by competing with Sp1 for BTE binding. Thus, the characterization of this protein expands the repertoire of BTEB-like members of the Sp1 family involved in transcriptional repression. Furthermore, our results suggest a mechanism of repression for BTEB3 involving direct repression by the N terminus via interaction with mSin3A and HDAC-1 and competition with Sp1 via the DNA-binding domain.", "title": "The Sp1-like protein BTEB3 inhibits transcription via the basic transcription element box by interacting with mSin3A and HDAC-1 co-repressors and competing with Sp1." }, { "docid": "35448676", "text": "3'-Ends of almost all eukaryotic mRNAs are generated by endonucleolytic cleavage and addition of a poly(A) tail. In mammalian cells, the reaction depends on the sequence AAUAAA upstream of the cleavage site, a degenerate GU-rich sequence element downstream of the cleavage site and stimulatory sequences upstream of AAUAAA. Six factors have been identified that carry out the two reactions. With a single exception, they have been purified to homogeneity and cDNAs for 11 subunits have been cloned. Some of the cooperative RNA-protein and protein-protein interactions within the processing complex have been analyzed, but many details, including the identity of the endonuclease, remain unknown. Several examples of regulated polyadenylation are being analyzed at the molecular level. In the yeast Saccharomyces cerevisiae, sequences directing cleavage and polyadenylation are more degenerate than in metazoans, and a downstream element has not been identified. The list of processing factors may be complete now with approximately a dozen polypeptides, but their functions in the reaction are largely unknown. 3'-Processing is known to be coupled to transcription. This connection is thought to involve interactions of processing factors with the mRNA cap as well as with RNA polymerase II.", "title": "3'-End processing of pre-mRNA in eukaryotes." }, { "docid": "25606339", "text": "TLR3 has been implicated in the pathogenesis of several viral infections, including SIV- and HIV-1-induced inflammation and AIDS. However the molecular mechanisms of these TLR3-mediated effects are not known, and it is not known whether HIV interacts with cellular TLR3 to affect disease process. Here we investigate the effects of TLR3 ligands on HIV-1 transactivation using both primary human macrophages and cells containing integrated copies of the HIV-1 promoter. We demonstrate that TLR3 activation induced upregulation of transcription factors such as c-Jun, CCAAT/enhancer-binding protein alpha (CEBPA), signal transducer and activator of transcription (STAT)-1, STAT-2, RELB, and nuclear factor kappa-B1 (NFκB1), most of which are known to regulate the HIV promoter activity. We also demonstrate that TLR3 activation increased HIV-1 transactivation via the c-Jun N-terminal kinase (JNK) and NFκB pathways. This was associated with epigenetic modifications, including decreased histone deacetylase activity, increased histone acetyl transferase (HAT) activity, and increased acetylation of histones H3 and H4 at lysine residues in the nucleosome-0 and nucleosome-1 of the HIV-1 promoter. However, prolonged TLR3 activation decreased HIV-1 transactivation, decreased HAT activity and Tat transcription, and suppressed viral replication. Overall, data suggests that TLR3 can act as viral sensor to mediate viral transactivation, cellular signaling, innate immune response, and inflammation in HIV-infected humans. Our study provides novel insights into the molecular basis for these TLR3-mediated effects.", "title": "Toll-like receptor-3 mediates HIV-1 transactivation via NFκB and JNK pathways and histone acetylation, but prolonged activation suppresses Tat and HIV-1 replication." }, { "docid": "24552097", "text": "BACKGROUND In the plant sciences there are two widely applied technologies for measuring nuclear DNA content: Feulgen absorbance cytophotometry and flow cytometry (FCM). While FCM is, with good reasons, increasingly popular among plant scientists, absorbance-cytophotometric techniques lose ground. This results in a narrowing of the methodological repertoire, which is neither desirable nor beneficial. Both approaches have their advantages, but static cytophotometry seems to pose more instrumental difficulties and material-based problems than FCM, so that Feulgen-based data in the literature are often less reliable than one would expect. SCOPE The purpose of this article is to present a selective overview of the field of nuclear DNA content measurement, and C-values in particular, with a focus on the technical difficulties imposed by the characteristics of the biological material and with some comments on the photometrical aspects of the work. For over 20 years it has been known that plant polyphenols cause problems in Feulgen DNA cytophotometry, since they act as major staining inhibitors leading to unreliable results. However, little information is available about the chemical classes of plant metabolites capable of DNA staining interference and the mechanisms of their inhibition. Plant slimes are another source of concern. \n CONCLUSIONS In FCM research to uncover the effects of secondary metabolites on measurement results has begun only recently. In particular, the analysis of intraspecific genome size variation demands a stringent methodology which accounts for inhibitors. FCM tests for inhibitory effects of endogenous metabolites should become obligatory. The use of dry seeds for harvesting embryo and endosperm nuclei for FCM and Feulgen densitometry may often provide a means of circumventing staining inhibitors. The importance of internal standardization is highlighted. Our goal is a better understanding of phytochemical/cytochemical interactions in plant DNA photometry for the benefit of an ever-growing list of plant genome sizes.", "title": "Cytochemistry and C-values: the less-well-known world of nuclear DNA amounts." }, { "docid": "1391126", "text": "Primates often rely on vocal communication to mediate social interactions. Although much is known about the acoustic structure of primate vocalizations and the social context in which they are usually uttered, our knowledge about the neocortical control of audio-vocal interactions in primates is still incipient, being mostly derived from lesion studies in squirrel monkeys and macaques. To map the neocortical areas related to vocal control in a New World primate species, the common marmoset, we employed a method previously used with success in other vertebrate species: Analysis of the expression of the immediate early gene Egr-1 in freely behaving animals. The neocortical distribution of Egr-1 immunoreactive cells in three marmosets that were exposed to the playback of conspecific vocalizations and vocalized spontaneously (H/V group) was compared to data from three other marmosets that also heard the playback but did not vocalize (H/n group). The anterior cingulate cortex, the dorsomedial prefrontal cortex and the ventrolateral prefrontal cortex presented a higher number of Egr-1 immunoreactive cells in the H/V group than in H/n animals. Our results provide direct evidence that the ventrolateral prefrontal cortex, the region that comprises Broca's area in humans and has been associated with auditory processing of species-specific vocalizations and orofacial control in macaques, is engaged during vocal output in marmosets. Altogether, our results support the notion that the network of neocortical areas related to vocal communication in marmosets is quite similar to that of Old world primates. The vocal production role played by these areas and their importance for the evolution of speech in primates are discussed.", "title": "Activation of Frontal Neocortical Areas by Vocal Production in Marmosets" }, { "docid": "27049238", "text": "Red blood cells are known to change shape in response to local flow conditions. Deformability affects red blood cell physiological function and the hydrodynamic properties of blood. The immersed boundary method is used to simulate three-dimensional membrane-fluid flow interactions for cells with the same internal and external fluid viscosities. The method has been validated for small deformations of an initially spherical capsule in simple shear flow for both neo-Hookean and the Evans-Skalak membrane models. Initially oblate spheroidal capsules are simulated and it is shown that the red blood cell membrane exhibits asymptotic behavior as the ratio of the dilation modulus to the extensional modulus is increased and a good approximation of local area conservation is obtained. Tank treading behavior is observed and its period calculated.", "title": "Large deformation of red blood cell ghosts in a simple shear flow." }, { "docid": "13794374", "text": "Lipid droplets are ubiquitous triglyceride and sterol ester storage organelles required for energy storage homeostasis and biosynthesis. Although little is known about lipid droplet formation and regulation, it is clear that members of the PAT (perilipin, adipocyte differentiation related protein, tail interacting protein of 47 kDa) protein family coat the droplet surface and mediate interactions with lipases that remobilize the stored lipids. We identified key Drosophila candidate genes for lipid droplet regulation by RNA interference (RNAi) screening with an image segmentation-based optical read-out system, and show that these regulatory functions are conserved in the mouse. Those include the vesicle-mediated Coat Protein Complex I (COPI) transport complex, which is required for limiting lipid storage. We found that COPI components regulate the PAT protein composition at the lipid droplet surface, and promote the association of adipocyte triglyceride lipase (ATGL) with the lipid droplet surface to mediate lipolysis. Two compounds known to inhibit COPI function, Exo1 and Brefeldin A, phenocopy COPI knockdowns. Furthermore, RNAi inhibition of ATGL and simultaneous drug treatment indicate that COPI and ATGL function in the same pathway. These data indicate that the COPI complex is an evolutionarily conserved regulator of lipid homeostasis, and highlight an interaction between vesicle transport systems and lipid droplets.", "title": "COPI Complex Is a Regulator of Lipid Homeostasis" }, { "docid": "23423230", "text": "Bartonella henselae is an arthropod-borne zoonotic pathogen causing intraerythrocytic bacteraemia in the feline reservoir host and a broad range of clinical manifestations in incidentally infected humans. Remarkably, B. henselae can specifically colonize the human vascular endothelium, resulting in inflammation and the formation of vasoproliferative lesions known as bacillary angiomatosis and bacillary peliosis. Cultured human endothelial cells provide an in vitro system to study this intimate interaction of B. henselae with the vascular endothelium. However, little is known about the bacterial virulence factors required for this pathogenic process. Recently, we identified the type IV secretion system (T4SS) VirB as an essential pathogenicity factor in Bartonella, required to establish intraerythrocytic infection in the mammalian reservoir. Here, we demonstrate that the VirB T4SS also mediates most of the virulence attributes associated with the interaction of B. henselae during the interaction with human endothelial cells. These include: (i) massive rearrangements of the actin cytoskeleton, resulting in the formation of bacterial aggregates and their internalization by the invasome structure; (ii) nuclear factor kappaB-dependent proinflammatory activation, leading to cell adhesion molecule expression and chemokine secretion, and (iii) inhibition of apoptotic cell death, resulting in enhanced endothelial cell survival. Moreover, we show that the VirB system mediates cytostatic and cytotoxic effects at high bacterial titres, which interfere with a potent VirB-independent mitogenic activity. We conclude that the VirB T4SS is a major virulence determinant of B. henselae, required for targeting multiple endothelial cell functions exploited by this vasculotropic pathogen.", "title": "The VirB type IV secretion system of Bartonella henselae mediates invasion, proinflammatory activation and antiapoptotic protection of endothelial cells." }, { "docid": "2659805", "text": "A number of methods have been developed to assist subjects in providing an estimate of portion size but their application in improving portion size estimation by children has not been investigated systematically. The aim was to develop portion size assessment tools for use with children and to assess the accuracy of children's estimates of portion size using the tools. The tools were food photographs, food models and an interactive portion size assessment system (IPSAS). Children (n 201), aged 4-16 years, were supplied with known quantities of food to eat, in school. Food leftovers were weighed. Children estimated the amount of each food using each tool, 24 h after consuming the food. The age-specific portion sizes represented were based on portion sizes consumed by children in a national survey. Significant differences were found between the accuracy of estimates using the three tools. Children of all ages performed well using the IPSAS and food photographs. The accuracy and precision of estimates made using the food models were poor. For all tools, estimates of the amount of food served were more accurate than estimates of the amount consumed. Issues relating to reporting of foods left over which impact on estimates of the amounts of foods actually consumed require further study. The IPSAS has shown potential for assessment of dietary intake with children. Before practical application in assessment of dietary intake of children the tool would need to be expanded to cover a wider range of foods and to be validated in a 'real-life' situation.", "title": "Children's estimates of food portion size: the development and evaluation of three portion size assessment tools for use with children." }, { "docid": "23577014", "text": "During Caenorhabditis elegans oocyte meiosis, a multi-protein ring complex (RC) localized between homologous chromosomes, promotes chromosome congression through the action of the chromokinesin KLP-19. While some RC components are known, the mechanism of RC assembly has remained obscure. We show that SUMO E3 ligase GEI-17/PIAS is required for KLP-19 recruitment to the RC, and proteomic analysis identified KLP-19 as a SUMO substrate in vivo. In vitro analysis revealed that KLP-19 is efficiently sumoylated in a GEI-17-dependent manner, while GEI-17 undergoes extensive auto-sumoylation. GEI-17 and another RC component, the kinase BUB-1, contain functional SUMO interaction motifs (SIMs), allowing them to recruit SUMO modified proteins, including KLP-19, into the RC. Thus, dynamic SUMO modification and the presence of SIMs in RC components generate a SUMO-SIM network that facilitates assembly of the RC. Our results highlight the importance of SUMO-SIM networks in regulating the assembly of dynamic protein complexes.", "title": "A SUMO-Dependent Protein Network Regulates Chromosome Congression during Oocyte Meiosis" }, { "docid": "26083387", "text": "The Saccharomyces cerevisiae DNA helicase Rrm3p is needed for normal fork progression through >1000 discrete sites scattered throughout the genome. Here we show that replication of all yeast chromosomes was markedly delayed in rrm3 cells. Delayed replication was seen even in a region that lacks any predicted Rrm3p-dependent sites. Based on the pattern of replication intermediates in two-dimensional gels, the rate of fork movement in rrm3 cells appeared similar to wild-type except at known Rrm3p-dependent sites. These data suggest that although Rrm3p has a global role in DNA replication, its activity is needed only or primarily at specific, difficult-to-replicate sites. By the criterion of chromatin immunoprecipitation, Rrm3p was associated with both Rrm3p-dependent and -independent sites, and moved with the replication fork through both. In addition, Rrm3p interacted with Pol2p, the catalytic subunit of DNA polymerase epsilon, in vivo. Thus, rather than being recruited to its sites of action when replication forks stall at these sites, Rrm3p is likely a component of the replication fork apparatus.", "title": "The S. cerevisiae Rrm3p DNA helicase moves with the replication fork and affects replication of all yeast chromosomes." }, { "docid": "30261663", "text": "In eukaryotes, a surveillance mechanism known as nonsense-mediated decay (NMD) degrades the mRNA when a premature-termination codon (PTC) is present. NMD requires translation to read the frame of the mRNA and detect the PTC. During pre-mRNA splicing, the exon-exon junction complex (EJC) is recruited to a region 20-24 nt upstream of the exon junction on the mature mRNA. The presence of a PTC upstream from the EJC elicits NMD. Eukaryotic initiation factor 4A (eIF4A) III is a nuclear protein that interacts physically or functionally with translation initiation factors eIF4G and eIF4B, respectively, and shares strikingly high identity with the initiation factors eIF4AI/II. Here we show that siRNA against eIF4AIII, but not against eIF4AI/II, inhibits NMD. Moreover, eIF4AIII, but not eIF4AI, is specifically recruited to the EJC during splicing. The observations that eIF4AIII is loaded onto the mRNA during splicing in the nucleus, has properties related to a translation initiation factor, and functions in NMD raises the possibility that eIF4AIII substitutes for eIF4AI/II during NMD.", "title": "A nuclear translation-like factor eIF4AIII is recruited to the mRNA during splicing and functions in nonsense-mediated decay." }, { "docid": "9669099", "text": "Binding within or nearby target genes involved in cell proliferation and survival enables the p53 tumor suppressor gene to regulate their transcription and cell-cycle progression. Using genome-wide chromatin-binding profiles, we describe binding of p53 also to regions located distantly from any known p53 target gene. Interestingly, many of these regions possess conserved p53-binding sites and all known hallmarks of enhancer regions. We demonstrate that these p53-bound enhancer regions (p53BERs) indeed contain enhancer activity and interact intrachromosomally with multiple neighboring genes to convey long-distance p53-dependent transcription regulation. Furthermore, p53BERs produce, in a p53-dependent manner, enhancer RNAs (eRNAs) that are required for efficient transcriptional enhancement of interacting target genes and induction of a p53-dependent cell-cycle arrest. Thus, our results ascribe transcription enhancement activity to p53 with the capacity to regulate multiple genes from a single genomic binding site. Moreover, eRNA production from p53BERs is required for efficient p53 transcription enhancement.", "title": "eRNAs are required for p53-dependent enhancer activity and gene transcription." }, { "docid": "21380348", "text": "Vitamins are compounds that are essential for the normal growth, reproduction and functioning of the human body. Of the 13 known vitamins, vitamins A, D, E and K are lipophilic compounds and are therefore called fat-soluble vitamins. Because of their lipophilicity, fat-soluble vitamins are solubilized and transported by intracellular carrier proteins to exert their actions and to be metabolized properly. Vitamin A and its derivatives, collectively called retinoids, are solubilized by intracellular retinoid-binding proteins such as cellular retinol-binding protein (CRBP), cellular retinoic acid-binding protein (CRABP) and cellular retinal-binding protein (CRALBP). These proteins act as chaperones that regulate the metabolism, signaling and transport of retinoids. CRALBP-mediated intracellular retinoid transport is essential for vision in human. α-Tocopherol, the main form of vitamin E found in the body, is transported by α-tocopherol transfer protein (α-TTP) in hepatic cells. Defects of α-TTP cause vitamin E deficiency and neurological disorders in humans. Recently, it has been shown that the interaction of α-TTP with phosphoinositides plays a critical role in the intracellular transport of α-tocopherol and is associated with familial vitamin E deficiency. In this review, we summarize the mechanisms and biological significance of the intracellular transport of vitamins A and E.", "title": "Intracellular transport of fat-soluble vitamins A and E." } ]

[ { "docid": "9505448", "text": "Activation of the mammalian Notch receptor after ligand binding relies on a succession of events including metalloprotease-cleavage, endocytosis, monoubiquitination, and eventually processing by the gamma-secretase, giving rise to a soluble, transcriptionally active molecule. The Notch1 receptor was proposed to be monoubiquitinated before its gamma-secretase cleavage; the targeted lysine has been localized to its submembrane domain. Investigating how this step might be regulated by a deubiquitinase (DUB) activity will provide new insight for understanding Notch receptor activation and downstream signaling. An immunofluorescence-based screening of an shRNA library allowed us to identify eIF3f, previously known as one of the subunits of the translation initiation factor eIF3, as a DUB targeting the activated Notch receptor. We show that eIF3f has an intrinsic DUB activity. Knocking down eIF3f leads to an accumulation of monoubiquitinated forms of activated Notch, an effect counteracted by murine WT eIF3f but not by a catalytically inactive mutant. We also show that eIF3f is recruited to activated Notch on endocytic vesicles by the putative E3 ubiquitin ligase Deltex1, which serves as a bridging factor. Finally, catalytically inactive forms of eIF3f as well as shRNAs targeting eIF3f repress Notch activation in a coculture assay, showing that eIF3f is a new positive regulator of the Notch pathway. Our results support two new and provocative conclusions: (1) The activated form of Notch needs to be deubiquitinated before being processed by the gamma-secretase activity and entering the nucleus, where it fulfills its transcriptional function. (2) The enzyme accounting for this deubiquitinase activity is eIF3f, known so far as a translation initiation factor. These data improve our knowledge of Notch signaling but also open new avenues of research on the Zomes family and the translation initiation factors.", "title": "The Translation Initiation Factor 3f (eIF3f) Exhibits a Deubiquitinase Activity Regulating Notch Activation" } ]

[ { "docid": "13794374", "text": "Lipid droplets are ubiquitous triglyceride and sterol ester storage organelles required for energy storage homeostasis and biosynthesis. Although little is known about lipid droplet formation and regulation, it is clear that members of the PAT (perilipin, adipocyte differentiation related protein, tail interacting protein of 47 kDa) protein family coat the droplet surface and mediate interactions with lipases that remobilize the stored lipids. We identified key Drosophila candidate genes for lipid droplet regulation by RNA interference (RNAi) screening with an image segmentation-based optical read-out system, and show that these regulatory functions are conserved in the mouse. Those include the vesicle-mediated Coat Protein Complex I (COPI) transport complex, which is required for limiting lipid storage. We found that COPI components regulate the PAT protein composition at the lipid droplet surface, and promote the association of adipocyte triglyceride lipase (ATGL) with the lipid droplet surface to mediate lipolysis. Two compounds known to inhibit COPI function, Exo1 and Brefeldin A, phenocopy COPI knockdowns. Furthermore, RNAi inhibition of ATGL and simultaneous drug treatment indicate that COPI and ATGL function in the same pathway. These data indicate that the COPI complex is an evolutionarily conserved regulator of lipid homeostasis, and highlight an interaction between vesicle transport systems and lipid droplets.", "title": "COPI Complex Is a Regulator of Lipid Homeostasis" }, { "docid": "3222187", "text": "Genome-wide association studies (GWAS) have identified common polymorphisms in or near GC, CYP2R1, CYP24A1, and NADSYN1/DHCR7 genes to be associated with circulating levels of 25-hydroxyvitamin D [25(OH)D] in European populations. To replicate these GWAS findings, we examined six selected polymorphisms from these regions and their relation with circulating 25(OH)D levels in 1,605 Hispanic women (629 U.S. Hispanics and 976 Mexicans) and 354 non-Hispanic White (NHW) women. We also assessed the potential interactions between these variants and known non-genetic predictors of 25(OH)D levels, including body mass index (BMI), sunlight exposure and vitamin D intake from diet and supplements. The minor alleles of the two GC polymorphisms (rs7041 and rs2282679) were significantly associated with lower 25(OH)D levels in both Hispanic and NHW women. The CYP2R1 polymorphism, rs2060793, also was significantly associated with 25(OH)D levels in both groups. We found no significant associations for the polymorphisms in the CYP24A1. In Hispanic controls, 25(OH)D levels were significantly associated with the rs12785878T and rs1790349G haplotype in the NADSYN1/DHCR7 region. Significant interactions between GC rs2282679 and BMI and between rs12785878 and time spent in outdoor activities were observed. These results provide further support for the contribution of common genetic variants to individual variability in circulating 25(OH)D levels. The observed interactions between SNPs and non-genetic factors warrant confirmation.", "title": "Genetic variants and non-genetic factors predict circulating vitamin D levels in Hispanic and non-Hispanic White women: the Breast Cancer Health Disparities Study." }, { "docid": "14461101", "text": "Certain bacterial adhesins appear to promote a pathogen's extracellular lifestyle rather than its entry into host cells. However, little is known about the stimuli elicited upon such pathogen host-cell interactions. Here, we report that type IV pili (Tfp)-producing Neisseria gonorrhoeae (P(+)GC) induces an immediate recruitment of caveolin-1 (Cav1) in the host cell, which subsequently prevents bacterial internalization by triggering cytoskeletal rearrangements via downstream phosphotyrosine signaling. A broad and unbiased analysis of potential interaction partners for tyrosine-phosphorylated Cav1 revealed a direct interaction with the Rho-family guanine nucleotide exchange factor Vav2. Both Vav2 and its substrate, the small GTPase RhoA, were found to play a direct role in the Cav1-mediated prevention of bacterial uptake. Our findings, which have been extended to enteropathogenic Escherichia coli, highlight how Tfp-producing bacteria avoid host cell uptake. Further, our data establish a mechanistic link between Cav1 phosphorylation and pathogen-induced cytoskeleton reorganization and advance our understanding of caveolin function.", "title": "Tyrosine-Phosphorylated Caveolin-1 Blocks Bacterial Uptake by Inducing Vav2-RhoA-Mediated Cytoskeletal Rearrangements" }, { "docid": "7878807", "text": "The Ndc80 complex is the key microtubule-binding element of the kinetochore. In contrast to the well-characterized interaction of Ndc80-Nuf2 heads with microtubules, little is known about how the Spc24-25 heterodimer connects to centromeric chromatin. Here, we present molecular details of Spc24-25 in complex with the histone-fold protein Cnn1/CENP-T illustrating how this connection ultimately links microtubules to chromosomes. The conserved Ndc80 receptor motif of Cnn1 is bound as an α helix in a hydrophobic cleft at the interface between Spc24 and Spc25. Point mutations that disrupt the Ndc80-Cnn1 interaction also abrogate binding to the Mtw1 complex and are lethal in yeast. We identify a Cnn1-related motif in the Dsn1 subunit of the Mtw1 complex, necessary for Ndc80 binding and essential for yeast growth. Replacing this region with the Cnn1 peptide restores viability demonstrating functionality of the Ndc80-binding module in different molecular contexts. Finally, phosphorylation of the Cnn1 N-terminus coordinates the binding of the two competing Ndc80 interaction partners. Together, our data provide structural insights into the modular binding mechanism of the Ndc80 complex to its centromere recruiters.", "title": "A structural basis for kinetochore recruitment of the Ndc80 complex via two distinct centromere receptors." }, { "docid": "25942757", "text": "The substantial importance of P-selectin glycoprotein ligand 1 (PSGL-1) in leukocyte trafficking has continued to emerge beyond its initial identification as a selectin ligand. PSGL-1 seemed to be a relatively simple molecule with an extracellular mucin domain extended as a flexible rod, teleologically consistent with its primary role in tethering leukocytes to endothelial selectins. The rolling interaction between leukocyte and endothelium mediated by this selectin-PSGL-1 interaction requires branched O-glycan extensions on specific PSGL-1 amino acid residues. In some cells, such as neutrophils, the glycosyltransferases involved in formation of the O-glycans are constitutively expressed, while in other cells, such as T cells, they are expressed only after appropriate activation. Thus, PSGL-1 supports leukocyte recruitment in both innate and adaptive arms of the immune response. A complex array of amino acids within the selectins engage multiple sugar residues of the branched O-glycans on PSGL-1 and provide the molecular interactions responsible for the velcro-like catch bonds that support leukocyte rolling. Such binding of PSGL-1 can also induce signaling events that influence cell phenotype and function. Scrutiny of PSGL-1 has revealed a better understanding of how it performs as a selectin ligand and yielded unexpected insights that extend its scope from supporting leukocyte rolling in inflammatory settings to homeostasis including stem cell homing to the thymus and mature T-cell homing to secondary lymphoid organs. PSGL-1 has been found to bind homeostatic chemokines CCL19 and CCL21 and to support the chemotactic response to these chemokines. Surprisingly, the O-glycan modifications of PSGL-1 that support rolling mediated by selectins in inflammatory conditions interfere with PSGL-1 binding to homeostatic chemokines and thereby limit responsiveness to the chemotactic cues used in steady state T-cell traffic. The multi-level influence of PSGL-1 on cell traffic in both inflammatory and steady state settings is therefore substantially determined by the orchestrated addition of O-glycans. However, central as specific O-glycosylation is to PSGL-1 function, in vivo regulation of PSGL-1 glycosylation in T cells remains poorly understood. It is our purpose herein to review what is known, and not known, of PSGL-1 glycosylation and to update understanding of PSGL-1 functional scope.", "title": "PSGL-1 function in immunity and steady state homeostasis." }, { "docid": "885056", "text": "Steroid receptor RNA activator (SRA), the only known RNA coactivator, augments transactivation by nuclear receptors (NRs). We identified SLIRP (SRA stem-loop interacting RNA binding protein) binding to a functional substructure of SRA, STR7. SLIRP is expressed in normal and tumor tissues, contains an RNA recognition motif (RRM), represses NR transactivation in a SRA- and RRM-dependent manner, augments the effect of Tamoxifen, and modulates association of SRC-1 with SRA. SHARP, a RRM-containing corepressor, also binds STR7, augmenting repression with SLIRP. SLIRP colocalizes with SKIP (Chr14q24.3), another NR coregulator, and reduces SKIP-potentiated NR signaling. SLIRP is recruited to endogenous promoters (pS2 and metallothionein), the latter in a SRA-dependent manner, while NCoR promoter recruitment is dependent on SLIRP. The majority of the endogenous SLIRP resides in the mitochondria. Our data demonstrate that SLIRP modulates NR transactivation, suggest it may regulate mitochondrial function, and provide mechanistic insight into interactions between SRA, SLIRP, SRC-1, and NCoR.", "title": "Summary" }, { "docid": "350542", "text": "BACKGROUND Pleurocidin, a 25-mer antimicrobial peptide (AMP), is known to exert bactericidal activity. However, the synergistic activity and mechanism(s) of pleurocidin in combination with conventional antibiotics, and the antibiofilm effect of the peptide are poorly understood. \n METHODS The interaction between pleurocidin and antibiotics was evaluated using checkerboard assay. To study the mechanism(s) involved in their synergism, we detected hydroxyl radical formation using 3'-(p-hydroxyphenyl) fluorescein, measured the NAD(+)/NADH ratio by NAD(+) cycling assay, observed change in bacterial viability with the hydroxyl radical scavenger thiourea, and investigated cytoplasmic membrane damage using propidium iodide. Also, the antibiofilm effect of pleurocidin was examined with the tissue culture plate method. \n RESULTS All combinations of pleurocidin and antibiotics showed synergistic interaction against bacterial strains (fractional inhibitory concentration index (FICI)≤0.5) except for Enterococcus faecium treated with a combination of the peptide and ampicillin (FICI=0.75). We identified that pleurocidin alone and in combinations with antibiotics induced formation of hydroxyl radicals. The oxidative stress was caused by a transient NADH depletion and the addition of thiourea prevented bacterial death, especially in the case of the combined treatment of pleurocidin and ampicillin showing synergisms. The combination of pleurocidin and erythromycin increased permeability of bacterial cytoplasmic membrane. Additionally, pleurocidin exhibited a potent inhibitory effect on preformed biofilm of bacterial organisms. In conclusion, pleurocidin synergized with antibiotics through hydroxyl radical formation and membrane-active mechanism, and exerted antibiofilm activity. GENERAL SIGNIFICANCE The synergistic effect between pleurocidin and antibiotics suggests the AMP is a potential therapeutic agent and adjuvant for antimicrobial chemotherapy.", "title": "Antimicrobial peptide pleurocidin synergizes with antibiotics through hydroxyl radical formation and membrane damage, and exerts antibiofilm activity." }, { "docid": "10443642", "text": "RNAIII is the intracellular effector of the quorum-sensing system in Staphylococcus aureus. It is one of the largest regulatory RNAs (514 nucleotides long) that are known to control the expression of a large number of virulence genes. Here, we show that the 3' domain of RNAIII coordinately represses at the post-transcriptional level, the expression of mRNAs that encode a class of virulence factors that act early in the infection process. We demonstrate that the 3' domain acts primarily as an antisense RNA and rapidly anneals to these mRNAs, forming long RNA duplexes. The interaction between RNAIII and the mRNAs results in repression of translation initiation and triggers endoribonuclease III hydrolysis. These processes are followed by rapid depletion of the mRNA pool. In addition, we show that RNAIII and its 3' domain mediate translational repression of rot mRNA through a limited number of base pairings involving two loop-loop interactions. Since Rot is a transcriptional regulatory protein, we proposed that RNAIII indirectly acts on many downstream genes, resulting in the activation of the synthesis of several exoproteins. These data emphasize the multitude of regulatory steps affected by RNAIII and its 3' domain in establishing a network of S. aureus virulence factors.", "title": "Staphylococcus aureus RNAIII coordinately represses the synthesis of virulence factors and the transcription regulator Rot by an antisense mechanism." }, { "docid": "17209919", "text": "Cilia are sensory organelles that protrude from cell surfaces to monitor the surrounding environment. In addition to its role as sensory receiver, the cilium also releases extracellular vesicles (EVs). The release of sub-micron sized EVs is a conserved form of intercellular communication used by all three kingdoms of life. These extracellular organelles play important roles in both short and long range signaling between donor and target cells and may coordinate systemic responses within an organism in normal and diseased states. EV shedding from ciliated cells and EV–cilia interactions are evolutionarily conserved phenomena, yet remarkably little is known about the relationship between the cilia and EVs and the fundamental biology of EVs. Studies in the model organisms Chlamydomonas and Caenorhabditis elegans have begun to shed light on ciliary EVs. Chlamydomonas EVs are shed from tips of flagella and are bioactive. Caenorhabditis elegans EVs are shed and released by ciliated sensory neurons in an intraflagellar transport-dependent manner. Caenorhabditis elegans EVs play a role in modulating animal-to-animal communication, and this EV bioactivity is dependent on EV cargo content. Some ciliary pathologies, or ciliopathies, are associated with abnormal EV shedding or with abnormal cilia–EV interactions. Until the 21st century, both cilia and EVs were ignored as vestigial or cellular junk. As research interest in these two organelles continues to gain momentum, we envision a new field of cell biology emerging. Here, we propose that the cilium is a dedicated organelle for EV biogenesis and EV reception. We will also discuss possible mechanisms by which EVs exert bioactivity and explain how what is learned in model organisms regarding EV biogenesis and function may provide insight to human ciliopathies.", "title": "Ciliary Extracellular Vesicles: Txt Msg Organelles" }, { "docid": "22938539", "text": "A comprehensive mapping of interactions among Epstein-Barr virus (EBV) proteins and interactions of EBV proteins with human proteins should provide specific hypotheses and a broad perspective on EBV strategies for replication and persistence. Interactions of EBV proteins with each other and with human proteins were assessed by using a stringent high-throughput yeast two-hybrid system. Overall, 43 interactions between EBV proteins and 173 interactions between EBV and human proteins were identified. EBV-EBV and EBV-human protein interaction, or \"interactome\" maps provided a framework for hypotheses of protein function. For example, LF2, an EBV protein of unknown function interacted with the EBV immediate early R transactivator (Rta) and was found to inhibit Rta transactivation. From a broader perspective, EBV genes can be divided into two evolutionary classes, \"core\" genes, which are conserved across all herpesviruses and subfamily specific, or \"noncore\" genes. Our EBV-EBV interactome map is enriched for interactions among proteins in the same evolutionary class. Furthermore, human proteins targeted by EBV proteins were enriched for highly connected or \"hub\" proteins and for proteins with relatively short paths to all other proteins in the human interactome network. Targeting of hubs might be an efficient mechanism for EBV reorganization of cellular processes.", "title": "Epstein-Barr virus and virus human protein interaction maps." }, { "docid": "24384587", "text": "Interleukin-18 (IL18) participates in atherogenesis through several putative mechanisms. Interruption of IL18 action reduces atherosclerosis in mice. Here, we show that absence of the IL18 receptor (IL18r) does not affect atherosclerosis in apolipoprotein E–deficient (Apoe−/−) mice, nor does it affect IL18 cell surface binding to or signaling in endothelial cells. As identified initially by co-immunoprecipitation with IL18, we found that IL18 interacts with the Na-Cl co-transporter (NCC; also known as SLC12A3), a 12-transmembrane-domain ion transporter protein preferentially expressed in the kidney. NCC is expressed in atherosclerotic lesions, where it colocalizes with IL18r. In Apoe−/− mice, combined deficiency of IL18r and NCC, but not single deficiency of either protein, protects mice from atherosclerosis. Peritoneal macrophages from Apoe−/− mice or from Apoe−/− mice lacking IL18r or NCC show IL18 binding and induction of cell signaling and cytokine and chemokine expression, but macrophages from Apoe−/− mice with combined deficiency of IL18r and NCC have a blunted response. An interaction between NCC and IL18r on macrophages was detected by co-immunoprecipitation. IL18 binds to the cell surface of NCC-transfected COS-7 cells, which do not express IL18r, and induces cell signaling and cytokine expression. This study identifies NCC as an IL18-binding protein that collaborates with IL18r in cell signaling, inflammatory molecule expression, and experimental atherogenesis.", "title": "Interleukin 18 function in atherosclerosis is mediated by the interleukin 18 receptor and the Na-Cl co-transporter" }, { "docid": "23423230", "text": "Bartonella henselae is an arthropod-borne zoonotic pathogen causing intraerythrocytic bacteraemia in the feline reservoir host and a broad range of clinical manifestations in incidentally infected humans. Remarkably, B. henselae can specifically colonize the human vascular endothelium, resulting in inflammation and the formation of vasoproliferative lesions known as bacillary angiomatosis and bacillary peliosis. Cultured human endothelial cells provide an in vitro system to study this intimate interaction of B. henselae with the vascular endothelium. However, little is known about the bacterial virulence factors required for this pathogenic process. Recently, we identified the type IV secretion system (T4SS) VirB as an essential pathogenicity factor in Bartonella, required to establish intraerythrocytic infection in the mammalian reservoir. Here, we demonstrate that the VirB T4SS also mediates most of the virulence attributes associated with the interaction of B. henselae during the interaction with human endothelial cells. These include: (i) massive rearrangements of the actin cytoskeleton, resulting in the formation of bacterial aggregates and their internalization by the invasome structure; (ii) nuclear factor kappaB-dependent proinflammatory activation, leading to cell adhesion molecule expression and chemokine secretion, and (iii) inhibition of apoptotic cell death, resulting in enhanced endothelial cell survival. Moreover, we show that the VirB system mediates cytostatic and cytotoxic effects at high bacterial titres, which interfere with a potent VirB-independent mitogenic activity. We conclude that the VirB T4SS is a major virulence determinant of B. henselae, required for targeting multiple endothelial cell functions exploited by this vasculotropic pathogen.", "title": "The VirB type IV secretion system of Bartonella henselae mediates invasion, proinflammatory activation and antiapoptotic protection of endothelial cells." }, { "docid": "11048759", "text": "The EBNA1 protein of Epstein-Barr virus (EBV) binds to and activates DNA replication from the EBV latent origin of replication, oriP, via a direct interaction with the two noncontiguous subelements of oriP. The EBNA1 molecules bound to the oriP subelements interact efficiently with each other by a DNA looping mechanism. We have previously mapped a region of EBNA1 (termed the looping region) that is required to mediate the interaction of the EBNA1 molecules bound to the oriP subelements. We now demonstrate that two fragments of this region of EBNA1, which consist largely of an eight amino acid repeat, can mediate homotypic interactions when transferred to another DNA-binding protein. Protein interactions mediated by the EBNA1 looping region appear to be dependent on DNA binding since these interactions were detected between DNA-bound forms of the proteins only.", "title": "Identification of Epstein-Barr virus nuclear antigen 1 protein domains that direct interactions at a distance between DNA-bound proteins." }, { "docid": "207972", "text": "Early region 3 (E3) of group C human adenoviruses (Ad) encodes several inhibitors of tumor necrosis factor alpha (TNF-alpha) cytolysis, including an E3 14.7-kDa protein (E3-14.7K) and a heterodimer containing two polypeptides of 10.4 and 14.5 kDa. To understand the mechanism by which the viral proteins inhibit TNF-alpha functions, the E3-14.7K protein was used to screen a HeLa cell cDNA library to search for interacting proteins in the yeast two-hybrid system. A novel protein containing multiple leucine zipper domains without any significant homology with any known protein was identified and has been named FIP-2 (for 14.7K-interacting protein). FIP-2 interacted with E3-14.7K both in vitro and in vivo. It colocalized with Ad E3-14.7K in the cytoplasm, especially near the nuclear membrane, and caused redistribution of the viral protein. FIP-2 by itself does not cause cell death; however, it can reverse the protective effect of E3-14.7K on cell killing induced by overexpression of the intracellular domain of the 55-kDa TNF receptor or by RIP, a death protein involved in the TNF-alpha and Fas apoptosis pathways. Deletion analysis indicates that the reversal effect of FIP-2 depends on its interaction with E3-14.7K. Three major mRNA forms of FIP-2 have been detected in multiple human tissues, and expression of the transcripts was induced by TNF-alpha treatment in a time-dependent manner in two different cell lines. FIP-2 has consensus sequences for several potential posttranslational modifications. These data suggest that FIP-2 is one of the cellular targets for Ad E3-14.7K and that its mechanism of affecting cell death involves the TNF receptor, RIP, or a downstream molecule affected by either of these two molecules.", "title": "Interaction of an adenovirus E3 14.7-kilodalton protein with a novel tumor necrosis factor alpha-inducible cellular protein containing leucine zipper domains." }, { "docid": "140874", "text": "It is thought that the H19 imprinting control region (ICR) directs the silencing of the maternally inherited Igf2 allele through a CTCF-dependent chromatin insulator. The ICR has been shown to interact physically with a silencer region in Igf2, differentially methylated region (DMR)1, but the role of CTCF in this chromatin loop and whether it restricts the physical access of distal enhancers to Igf2 is not known. We performed systematic chromosome conformation capture analyses in the Igf2/H19 region over >160 kb, identifying sequences that interact physically with the distal enhancers and the ICR. We found that, on the paternal chromosome, enhancers interact with the Igf2 promoters but that, on the maternal allele, this is prevented by CTCF binding within the H19 ICR. CTCF binding in the maternal ICR regulates its interaction with matrix attachment region (MAR)3 and DMR1 at Igf2, thus forming a tight loop around the maternal Igf2 locus, which may contribute to its silencing. Mutation of CTCF binding sites in the H19 ICR leads to loss of CTCF binding and de novo methylation of a CTCF target site within Igf2 DMR1, showing that CTCF can coordinate regional epigenetic marks. This systematic chromosome conformation capture analysis of an imprinting cluster reveals that CTCF has a critical role in the epigenetic regulation of higher-order chromatin structure and gene silencing over considerable distances in the genome.", "title": "CTCF binding at the H19 imprinting control region mediates maternally inherited higher-order chromatin conformation to restrict enhancer access to Igf2." }, { "docid": "26019505", "text": "The Hippo pathway regulates organ size and tissue homeostasis in response to multiple stimuli, including cell density and mechanotransduction. Pharmacological inhibition of phosphatases can also stimulate Hippo signaling in cell culture. We defined the Hippo protein-protein interaction network with and without inhibition of serine and threonine phosphatases by okadaic acid. We identified 749 protein interactions, including 599 previously unrecognized interactions, and demonstrated that several interactions with serine and threonine phosphatases were phosphorylation-dependent. Mutation of the T-loop of MST2 (mammalian STE20-like protein kinase 2), which prevented autophosphorylation, disrupted its association with STRIPAK (striatin-interacting phosphatase and kinase complex). Deletion of the amino-terminal forkhead-associated domain of SLMAP (sarcolemmal membrane-associated protein), a component of the STRIPAK complex, prevented its association with MST1 and MST2. Phosphatase inhibition produced temporally distinct changes in proteins that interacted with MOB1A and MOB1B (Mps one binder kinase activator-like 1A and 1B) and promoted interactions with upstream Hippo pathway proteins, such as MST1 and MST2, and with the trimeric protein phosphatase 6 complex (PP6). Mutation of three basic amino acids that are part of a phospho-serine- and phospho-threonine-binding domain in human MOB1B prevented its interaction with MST1 and PP6 in cells treated with okadaic acid. Collectively, our results indicated that changes in phosphorylation orchestrate interactions between kinases and phosphatases in Hippo signaling, providing a putative mechanism for pathway regulation.", "title": "Protein interaction network of the mammalian Hippo pathway reveals mechanisms of kinase-phosphatase interactions." }, { "docid": "9669099", "text": "Binding within or nearby target genes involved in cell proliferation and survival enables the p53 tumor suppressor gene to regulate their transcription and cell-cycle progression. Using genome-wide chromatin-binding profiles, we describe binding of p53 also to regions located distantly from any known p53 target gene. Interestingly, many of these regions possess conserved p53-binding sites and all known hallmarks of enhancer regions. We demonstrate that these p53-bound enhancer regions (p53BERs) indeed contain enhancer activity and interact intrachromosomally with multiple neighboring genes to convey long-distance p53-dependent transcription regulation. Furthermore, p53BERs produce, in a p53-dependent manner, enhancer RNAs (eRNAs) that are required for efficient transcriptional enhancement of interacting target genes and induction of a p53-dependent cell-cycle arrest. Thus, our results ascribe transcription enhancement activity to p53 with the capacity to regulate multiple genes from a single genomic binding site. Moreover, eRNA production from p53BERs is required for efficient p53 transcription enhancement.", "title": "eRNAs are required for p53-dependent enhancer activity and gene transcription." }, { "docid": "1383826", "text": "RNA molecules fulfill a diverse set of biological functions within cells, from the transfer of genetic information from DNA to protein, to enzymatic catalysis. Reflecting this range of roles, simple linear strings of RNA—made up of uracil, guanine, cytosine, and adenine—form a variety of complex three-dimensional structures. Just as proteins form distinct structural motifs such as zinc fingers and beta barrels, certain structures are also commonly adopted by RNA molecules. Among the most prevalent RNA structures is a motif known as the pseudoknot. First recognized in the turnip yellow mosaic virus [1], a pseudoknot is an RNA structure that is minimally composed of two helical segments connected by single-stranded regions or loops (Figure 1). Although several distinct folding topologies of pseudoknots exist, the best characterized is the H type. In the H-type fold, the bases in the loop of a hairpin form intramolecular pairs with bases outside of the stem (Figure 1A and ​and1B).1B). This causes the formation of a second stem and loop, resulting in a pseudoknot with two stems and two loops (Figure 1C). The two stems are able to stack on top of each other to form a quasi-continuous helix with one continuous and one discontinuous strand. The single-stranded loop regions often interact with the adjacent stems (loop 1–stem 2 or loop 2–stem 1) to form hydrogen bonds and to participate in the overall structure of the molecule. Hence, this relatively simple fold can yield very complex and stable RNA structures. Due to variation of the lengths of the loops and stems, as well as the types of interactions between them, pseudoknots represent a structurally diverse group. It is fitting that they play a variety of diverse roles in biology. These roles include forming the catalytic core of various ribozymes [2,3], self-splicing introns [4], and telomerase [5]. Additionally, pseudoknots play critical roles in altering gene expression by inducing ribosomal frameshifting in many viruses [6–9].", "title": "Pseudoknots: RNA Structures with Diverse Functions" }, { "docid": "4452659", "text": "Macroautophagy (hereafter referred to as autophagy) is a catabolic membrane trafficking process that degrades a variety of cellular constituents and is associated with human diseases. Although extensive studies have focused on autophagic turnover of cytoplasmic materials, little is known about the role of autophagy in degrading nuclear components. Here we report that the autophagy machinery mediates degradation of nuclear lamina components in mammals. The autophagy protein LC3/Atg8, which is involved in autophagy membrane trafficking and substrate delivery, is present in the nucleus and directly interacts with the nuclear lamina protein lamin B1, and binds to lamin-associated domains on chromatin. This LC3-lamin B1 interaction does not downregulate lamin B1 during starvation, but mediates its degradation upon oncogenic insults, such as by activated RAS. Lamin B1 degradation is achieved by nucleus-to-cytoplasm transport that delivers lamin B1 to the lysosome. Inhibiting autophagy or the LC3-lamin B1 interaction prevents activated RAS-induced lamin B1 loss and attenuates oncogene-induced senescence in primary human cells. Our study suggests that this new function of autophagy acts as a guarding mechanism protecting cells from tumorigenesis.", "title": "Autophagy mediates degradation of nuclear lamina" } ]

[ { "docid": "29023309", "text": "Salmonella typhimurium causes a localized enteric infection in immunocompetent individuals, whereas HIV-infected individuals develop a life-threatening bacteremia. Here we show that simian immunodeficiency virus (SIV) infection results in depletion of T helper type 17 (TH17) cells in the ileal mucosa of rhesus macaques, thereby impairing mucosal barrier functions to S. typhimurium dissemination. In SIV-negative macaques, the gene expression profile induced by S. typhimurium in ligated ileal loops was dominated by TH17 responses, including the expression of interleukin-17 (IL-17) and IL-22. TH17 cells were markedly depleted in SIV-infected rhesus macaques, resulting in blunted TH17 responses to S. typhimurium infection and increased bacterial dissemination. IL-17 receptor–deficient mice showed increased systemic dissemination of S. typhimurium from the gut, suggesting that IL-17 deficiency causes defects in mucosal barrier function. We conclude that SIV infection impairs the IL-17 axis, an arm of the mucosal immune response preventing systemic microbial dissemination from the gastrointestinal tract.", "title": "Simian immunodeficiency virus–induced mucosal interleukin-17 deficiency promotes Salmonella dissemination from the gut" } ]

[ { "docid": "8300657", "text": "Human and simian immunodeficiency virus (HIV and SIV) replicate optimally in activated memory CD4(+) T cells, a cell type that is abundant in the intestine. SIV infection of rhesus monkeys resulted in profound and selective depletion of CD4+ T cells in the intestine within days of infection, before any such changes in peripheral lymphoid tissues. The loss of CD4+ T cells in the intestine occurred coincident with productive infection of large numbers of mononuclear cells at this site. The intestine appears to be a major target for SIV replication and the major site of CD4+ T cell loss in early SIV infection.", "title": "Gastrointestinal tract as a major site of CD4+ T cell depletion and viral replication in SIV infection." }, { "docid": "1071991", "text": "Live attenuated simian immunodeficiency virus (SIV) vaccines (LAVs) remain the most efficacious of all vaccines in nonhuman primate models of HIV and AIDS, yet the basis of their robust protection remains poorly understood. Here we show that the degree of LAV-mediated protection against intravenous wild-type SIVmac239 challenge strongly correlates with the magnitude and function of SIV-specific, effector-differentiated T cells in the lymph node but not with the responses of such T cells in the blood or with other cellular, humoral and innate immune parameters. We found that maintenance of protective T cell responses is associated with persistent LAV replication in the lymph node, which occurs almost exclusively in follicular helper T cells. Thus, effective LAVs maintain lymphoid tissue-based, effector-differentiated, SIV-specific T cells that intercept and suppress early wild-type SIV amplification and, if present in sufficient frequencies, can completely control and perhaps clear infection, an observation that provides a rationale for the development of safe, persistent vectors that can elicit and maintain such responses.", "title": "Lymph node T cell responses predict the efficacy of live attenuated SIV vaccines" }, { "docid": "798152", "text": "Analysis of serum samples from 100 wild-caught or colony-born Sykes' monkeys (Cercopithecus mitis) in Kenya revealed that 59 animals had antibodies cross-reactive to human immunodeficiency virus type 2 (HIV-2) and to simian immunodeficiency viruses (SIVs). A lentivirus, designated SIVsyk, was isolated from five of six seropositive asymptomatic Sykes' monkeys, but in four cases isolation was possible only after depletion of CD8+ lymphocytes and cocultivation of the CD4(+)-enriched cell population with peripheral blood mononuclear cells from seronegative Sykes' monkeys. SIVsyk resembled other SIVs and HIVs morphologically, had an Mg2(+)-dependent reverse transcriptase enzyme, and replicated in and was cytopathic for CEMx174 and Sup-T1 cells. SIVsyk differred substantially from other SIVs, however, in that it failed to replicate in normal human, mangabey, and macaque peripheral blood mononuclear cells and serum from seropositive Sykes' monkeys immunoprecipitated env antigens from HIV-1 as well as from HIV-2, SIVsmm, and SIVagm. These data demonstrate a high prevalence of natural infection in Sykes' monkeys in Kenya with a lentivirus that appears to be unique with respect to its host range and antigenic cross-reactivity.", "title": "Isolation from African Sykes' monkeys (Cercopithecus mitis) of a lentivirus related to human and simian immunodeficiency viruses." }, { "docid": "44737533", "text": "METHODS To define potential common features of simian immunodeficiency virus (SIV) infections in different naturally infected host species, we compared the dynamics of viral replication in 31 African green monkeys (10 sabeus, 15 vervets and seven Caribbean AGMs), 14 mandrills and three sooty mangabeys (SMs) that were experimentally infected with their species-specific viruses. \n RESULTS After infection, these SIVs replicated rapidly reaching viral loads (VLs) of 10(5)-10(9) copies/ml of plasma between days 9-14 post-infection (p.i). Set point viremia was established between days 42 and 60 p.i., with levels of approximately 10(5)-10(6) copies/ml in SM and mandrills, and lower levels (10(3)-10(5) copies/ml) in AGMs. VL during the chronic phase did not correlate with viral genome structure: SIVmnd-2 (a vpx-containing virus) and SIVmnd-1 (which does not contain vpu or vpx) replicated to similar levels in mandrills. VL was dependent on virus strain: vervets infected with three different viral strains showed different patterns of viral replication. The pattern of viral replication of SIVagm.sab, which uses both CCR5 and CXCR4 co-receptors was similar to those of the other viruses. \n CONCLUSIONS Our results show a common pattern of SIV replication in naturally and experimentally infected hosts. This is similar overall to that observed in pathogenic SIV infection of macaques. This result indicates that differences in clinical outcome between pathogenic and non-pathogenic infections rely on host responses rather than the characteristics of the virus itself.", "title": "Simian immunodeficiency viruses replication dynamics in African non-human primate hosts: common patterns and species-specific differences." }, { "docid": "20357868", "text": "Primary simian immunodeficiency virus (SIV) isolated from sooty mangabey (SIVsm [n = 6]), stumptail (SIVstm [n = 1]), mandrill (SIVmnd [n = 1]), and African green (SIVagm [n = 1]) primates were examined for their ability to infect human cells and for their coreceptor requirements. All isolates infected human peripheral blood mononuclear cells (PBMCs) from a CCR5(+/+) donor, and seven of eight isolates tested also infected CCR5(-/-) PBMCs. Analysis of coreceptor utilization using GHOST and U87 cell lines revealed that all of the isolates tested used CCR5 and the orphan receptors STRL33 and GPR15. Coreceptors such as CCR2b, CCR3, CCR8, and CX3CR1 were also utilized by some primary SIV isolates. More importantly, we found that CXCR4 was used as a coreceptor by the SIVstm, the SIVagm, and four of the SIVsm isolates in GHOST and U87 cells. These data suggest that primary SIV isolates from diverse primate species can utilize CXCR4 for viral entry, similar to what has been described for human immunodeficiency viruses.", "title": "Simian immunodeficiency viruses of diverse origin can use CXCR4 as a coreceptor for entry into human cells." }, { "docid": "42065070", "text": "Early events during human immunodeficiency virus infections are considered to reflect the capacity of the host to control infection. We have studied early virus and host parameters during the early phase of simian immunodeficiency virus SIVmnd-1 nonpathogenic infection in its natural host, Mandrillus sphinx. Four mandrills were experimentally infected with a primary SIVmnd-1 strain derived from a naturally infected mandrill. Two noninfected control animals were monitored in parallel. Blood and lymph nodes were collected at three time points before infection, twice a week during the first month, and at days 60, 180, and 360 postinfection (p.i.). Anti-SIVmnd-1 antibodies were detected starting from days 28 to 32 p.i. Neither elevated temperature nor increased lymph node size were observed. The viral load in plasma peaked between days 7 to 10 p.i. (2 x 10(6) to 2 x 10(8) RNA equivalents/ml). Viremia then decreased 10- to 1,000-fold, reaching the viral set point between days 30 to 60 p.i. The levels during the chronic phase of infection were similar to that in the naturally infected donor mandrill (2 x 10(5) RNA equivalents/ml). The CD4(+) cell numbers and percentages in blood and lymph nodes decreased slightly (<10%) during primary infection, and CD8(+) cell numbers increased transiently. All values returned to preinfection infection levels by day 30 p.i. CD8(+) cell numbers or percentages, in peripheral blood and lymph nodes, did not increase during the 1 year of follow-up. In conclusion, SIVmnd-1 has the capacity for rapid and extensive replication in mandrills. Despite high levels of viremia, CD4(+) and CD8(+) cell numbers remained stable in the post-acute phase of infection, raising questions regarding the susceptibility of mandrill T cells to activation and/or cell death in response to SIVmnd-1 infection in vivo.", "title": "High levels of viral replication contrast with only transient changes in CD4(+) and CD8(+) cell numbers during the early phase of experimental infection with simian immunodeficiency virus SIVmnd-1 in Mandrillus sphinx." }, { "docid": "22705234", "text": "The African green monkey (AGM) is one of many African species endemically infected with simian immunodeficiency virus (SIV). Like the other natural hosts, AGMs do not succumb to AIDS and understanding the basis for this resistance to disease progression would be of enormous theoretical and practical importance. Early efforts by our group that concentrated on identifying immune mechanisms presumed to keep the virus under control failed to find any obvious candidates. The presumption of virus control was invalidated by the finding that SIVagm replicates in AGMs with the same vigor as HIV-1 does in humans. Focus therefore shifted to identifying possible immunopathologic features present in disease susceptible hosts but absent in the AGM natural host. The apparent immunologic tolerance of AGMs to the SIVagm core protein led to the development of a hypothesis implicating anti-Gag antibodies in the formation of immune complexes, virus trapping in the lymph nodes and immune dysfunction. The idea proved difficult to test in vivo and present work focuses on the possibility that Gag tolerance at the T-cell level plays an important role in preventing the catastrophic demise of the immune system characteristic of immunodeficiency virus infection of the heterologous primate host.", "title": "The role of the immune response during SIVagm infection of the African green monkey natural host." }, { "docid": "21274496", "text": "Simian immunodeficiency virus (SIV) naturally infects non-human primates in Africa. To date, 40 SIVs have been described both in natural hosts and in heterologous species. These viruses are highly diverse and the majority cluster in 6 relatively equidistant phylogenetic lineages. At least 8 SIVs are currently considered as recombinant viruses, based on different clustering patterns in different genomic regions. Only three types of genomes are known, based on the number of accessory genes: vpr-containing genomes, vpr-vpx containing genomes and vpr-vpu-containing genomes. vpx resulted by a duplication of the vpr gene following non-homologous recombination and is characteristic of SIVs infecting the Papionini tribe of monkeys and HIV-2 in humans. vpu is characteristic of SIVcpz and HIV-1 and may have originated from a recombination involving SIVs from cercopitecini monkeys. SIV seems to be non-pathogenic in the vast majority of natural hosts in spite of a high levels of viral replication. This is probably a consequence of virus-host adaptation, in which the incubation period of the disease generally exceeds the life span of the African primate host. SIVs also have a high propensity for cross-species transmission. In the new host, the outcome may vary from inapparent infection to highly pathogenic, the former being reported for African monkeys, whereas the latter being observed in macaques and humans. The high diversity of SIVs was generated by a high mutation rate due to a low fidelity of the reverse-transcriptase and active viral and host cell turnover, host-dependent evolution and recombination. Cross-species transmission is not rare, however preferential host switching may drive the majority of cross-species transmissions. Numerous SIVs tested so far are able to grow in vitro on human PBMC, therefore it has been postulated that SIV represents a threat for infection of humans in Central Africa and that AIDS is a zoonosis. However, although the simian origin of the two HIV types is broadly acknowledged, there are no data that AIDS is acquired like a zoonosis. SIV may undergo adaptation in the new human host in order to emerge in the general population. The study of SIV in their natural hosts should provide important clues to the real threat to human populations and also elucidate the mechanisms associated with a long-term persistent viral infection without clinical consequences for the host.", "title": "The history of SIVS and AIDS: epidemiology, phylogeny and biology of isolates from naturally SIV infected non-human primates (NHP) in Africa." }, { "docid": "20864487", "text": "Cytotoxic T-lymphocyte (CTL) responses to human immunodeficiency virus arise early after infection, but ultimately fail to prevent progression to AIDS. Human immunodeficiency virus may evade the CTL response by accumulating amino-acid replacements within CTL epitopes. We studied 10 CTL epitopes during the course of simian immunodeficiency virus disease progression in three related macaques. All 10 of these CTL epitopes accumulated amino-acid replacements and showed evidence of positive selection by the time the macaques died. Many of the amino-acid replacements in these epitopes reduced or eliminated major histocompatibility complex class I binding and/or CTL recognition. These findings strongly support the CTL 'escape' hypothesis.", "title": "Virus-specific cytotoxic T-lymphocyte responses select for amino-acid variation in simian immunodeficiency virus Env and Nef" }, { "docid": "11921405", "text": "The gut mucosal epithelium separates the host from the microbiota, but enteropathogens such as Salmonella Typhimurium (S.Tm) can invade and breach this barrier. Defenses against such acute insults remain incompletely understood. Using a murine model of Salmonella enterocolitis, we analyzed mechanisms limiting pathogen loads in the epithelium during early infection. Although the epithelium-invading S.Tm replicate initially, this intraepithelial replicative niche is restricted by expulsion of infected enterocytes into the lumen. This mechanism is compromised if inflammasome components (NAIP1-6, NLRC4, caspase-1/-11) are deleted, or ablated specifically in the epithelium, resulting in ∼100-fold higher intraepithelial loads and accelerated lymph node colonization. Interestingly, the cytokines downstream of inflammasome activation, interleukin (IL)-1α/β and IL-18, appear dispensable for epithelial restriction of early infection. These data establish the role of an epithelium-intrinsic inflammasome, which drives expulsion of infected cells to restrict the pathogen's intraepithelial proliferation. This may represent a general defense mechanism against mucosal infections.", "title": "Epithelium-intrinsic NAIP/NLRC4 inflammasome drives infected enterocyte expulsion to restrict Salmonella replication in the intestinal mucosa." }, { "docid": "22159299", "text": "Salmonella enterica serovar Typhimurium (S. Typhimurium) is a facultative intracellular pathogen that causes disease in a variety of hosts. S. Typhimurium actively invade host cells and typically reside within a membrane-bound compartment called the Salmonella-containing vacuole (SCV). The bacteria modify the fate of the SCV using two independent type III secretion systems (TTSS). TTSS are known to damage eukaryotic cell membranes and S. Typhimurium has been suggested to damage the SCV using its Salmonella pathogenicity island (SPI)-1 encoded TTSS. Here we show that this damage gives rise to an intracellular bacterial population targeted by the autophagy system during in vitro infection. Approximately 20% of intracellular S. Typhimurium colocalized with the autophagy marker GFP-LC3 at 1 h postinfection. Autophagy of S. Typhimurium was dependent upon the SPI-1 TTSS and bacterial protein synthesis. Bacteria targeted by the autophagy system were often associated with ubiquitinated proteins, indicating their exposure to the cytosol. Surprisingly, these bacteria also colocalized with SCV markers. Autophagy-deficient (atg5-/-) cells were more permissive for intracellular growth by S. Typhimurium than normal cells, allowing increased bacterial growth in the cytosol. We propose a model in which the host autophagy system targets bacteria in SCVs damaged by the SPI-1 TTSS. This serves to retain intracellular S. Typhimurium within vacuoles early after infection to protect the cytosol from bacterial colonization. Our findings support a role for autophagy in innate immunity and demonstrate that Salmonella infection is a powerful model to study the autophagy process.", "title": "Autophagy controls Salmonella infection in response to damage to the Salmonella-containing vacuole." }, { "docid": "13398997", "text": "The CD28/cytotoxic T-lymphocyte antigen 4 (CTLA-4)blocker belatacept selectively inhibits alloreactive T cell responses but is associated with a high incidence of acute rejection following renal transplantation,which led us to investigate the etiology of belatacept–resistant graft rejection. T cells can differentiate into functionally distinct subsets of memory T cellsthat collectively enable protection against diverse classes of pathogens and can cross-react with allogeneicantigen and mediate graft rejection. T helper 17(Th17) cells are a pro-inflammatory CD4+ lineage that provides immunity to pathogens and are pathogenic in autoimmune disease. We found that T helper 1 (Th1)and Th17 memory compartments contained a similar frequency of divided cells following allogeneic stimulation. Compared to Th1 cells, Th17 memory cells expressed significantly higher levels of the coinhibitory molecule CTLA-4. Stimulation in the presence of belatacept inhibited Th1 responses but augmented Th17 cells due to greater sensitivity to coinhibition by CTLA-4. Th17 cells from renal transplant recipients were resistant to ex vivo CD28/CTLA-4 blockade with belatacept, and an elevated frequency of Th17 memory cells was associated with acute rejection during belatacept therapy. These data highlight important differences in costimulatory and coinhibitory requirements of CD4+ memory subsets, and demonstrate that the heterogeneity of pathogen-derived memory has implications for immunomodulation strategies.", "title": "High CTLA-4 expression on Th17 cells results in increased sensitivity to CTLA-4 coinhibition and resistance to belatacept." }, { "docid": "35651106", "text": "Efficient T cell activation requires both TCR signals and costimulatory signals. CD28 is one of the molecules that provide costimulatory signals for T cells. We used mice deficient in CD28 expression (CD28-/- mice) to analyze the role of CD28 in the immune response against the intracellular bacterium Salmonella typhimurium, the causative agent of murine typhoid fever. CD28-/- mice were highly susceptible to infection with wild-type S. typhimurium and even failed to control infection with attenuated aroA- S. typhimurium. More detailed analysis revealed that CD28-/- animals did not mount a T-dependent Ab response and were highly impaired in the production of IFN-gamma. Thus, CD28 cosignaling is crucial for immunity against S. typhimurium. To our knowledge, this is the first report describing an essential role for CD28 in protective immunity against an intracellular microbial pathogen.", "title": "Critical role of CD28 in protective immunity against Salmonella typhimurium." }, { "docid": "37444589", "text": "Although 13 years have passed since identification of human immunodeficiency virus-1 (HIV-1) as the cause of AIDS, we do not yet know how HIV kills its primary target, the T cell that carries the CD4 antigen. We and others have shown an increase in the percentage of apoptotic cells among circulating CD4+ (and CD8+) T cells of HIV-seropositive individuals and an increase in frequency of apoptosis with disease progression. However, it is not known if this apoptosis occurs in infected or uninfected T cells. We show here, using in situ labelling of lymph nodes from HIV-infected children and SIV-infected macaques, that apoptosis occurs predominantly in bystander cells and not in the productively infected cells themselves. These data have implications for pathogenesis and therapy, namely, arguing that rational drug therapy may involve combination agents targeting viral replication in infected cells and apoptosis of uninfected cells.", "title": "Apoptosis occurs predominantly in bystander cells and not in productively infected cells of HIV- and SIV-infected lymph nodes" }, { "docid": "11233339", "text": "T-helper 17 (Th17) cells are characterized by producing interleukin-17 (IL-17, also called IL-17A), IL-17F, IL-21, and IL-22 and potentially TNF- α and IL-6 upon certain stimulation. IL-23, which promotes Th17 cell development, as well as IL-17 and IL-22 produced by the Th17 cells plays essential roles in various inflammatory diseases, such as experimental autoimmune encephalomyelitis, rheumatoid arthritis, colitis, and Concanavalin A-induced hepatitis. In this review, we summarize the characteristics of the functional role of Th17 cells, with particular focus on the Th17 cell-related cytokines such as IL-17, IL-22, and IL-23, in mouse models and human inflammatory diseases.", "title": "Pivotal Roles of T-Helper 17-Related Cytokines, IL-17, IL-22, and IL-23, in Inflammatory Diseases" }, { "docid": "18546584", "text": "CD4(+) helper T (Th) cells play a crucial role in the delicate balance between host defense and autoimmune disease. Two important populations of helper T cells are the proinflammatory, interleukin-17 (IL-17)-producing (Th17) cells and the anti-inflammatory forkhead box P3-positive (FoxP3(+)) T regulatory (Treg) cells. Here we show that all-trans retinoic acid (ATRA) and other agonists of the retinoic acid receptor alpha (RARalpha) inhibit the formation of Th17 cells and promote FoxP3 expression. Conversely, inhibition of retinoic acid signaling constrains transforming growth factor beta (TGF-beta1) induction of FoxP3. The effect of ATRA is mediated independently of IL-2, signal transducer and activator of transcription 5 (Stat5) and Stat3, representing a novel mechanism for the induction of FoxP3 in CD4 T cells. As previous studies have shown that vitamin A derivatives are protective in animal models of autoimmune disease, the current data suggest a previously unrecognized role for RARalpha in the regulation of CD4(+) T-cell differentiation and provide a mechanism for the anti-inflammatory effects of retinoic acid.", "title": "Retinoic acid inhibits Th17 polarization and enhances FoxP3 expression through a Stat-3/Stat-5 independent signaling pathway." }, { "docid": "19005293", "text": "Inflammation induced by recognition of pathogen-associated molecular patterns markedly affects subsequent adaptive responses. We asked whether the adaptive immune system can also affect the character and magnitude of innate inflammatory responses. We found that the response of memory, but not naive, CD4+ T cells enhances production of multiple innate inflammatory cytokines and chemokines (IICs) in the lung and that, during influenza infection, this leads to early control of virus. Memory CD4+ T cell–induced IICs and viral control require cognate antigen recognition and are optimal when memory cells are either T helper type 1 (TH1) or TH17 polarized but are independent of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) production and do not require activation of conserved pathogen recognition pathways. This represents a previously undescribed mechanism by which memory CD4+ T cells induce an early innate response that enhances immune protection against pathogens.", "title": "Memory CD4+ T cells induce innate responses independently of pathogen" }, { "docid": "51952430", "text": "The toll-like receptor (TLR) and interleukin (IL)-1 family of receptors share several signaling components, including the most upstream adapter, MyD88. We previously reported the discovery of B cell adapter for phosphoinositide 3-kinase (BCAP) as a novel toll-IL-1 receptor homology domain-containing adapter that regulates inflammatory responses downstream of TLR signaling. Here we find that BCAP plays a critical role downstream of both IL-1 and IL-18 receptors to regulate T helper (Th) 17 and Th1 cell differentiation, respectively. Absence of T cell intrinsic BCAP did not alter development of naturally arising Th1 and Th17 lineages but led to defects in differentiation to pathogenic Th17 lineage cells. Consequently, mice that lack BCAP in T cells had reduced susceptibility to experimental autoimmune encephalomyelitis. More importantly, we found that BCAP is critical for IL-1R-induced phosphoinositide 3-kinase-Akt-mechanistic target of rapamycin (mTOR) activation, and minimal inhibition of mTOR completely abrogated IL-1β-induced differentiation of pathogenic Th17 cells, mimicking BCAP deficiency. This study establishes BCAP as a critical link between IL-1R and the metabolic status of activated T cells that ultimately regulates the differentiation of inflammatory Th17 cells.", "title": "BCAP links IL-1R to the PI3K–mTOR pathway and regulates pathogenic Th17 cell differentiation" }, { "docid": "8063697", "text": "Pertussis is a highly contagious respiratory illness caused by the bacterial pathogen Bordetella pertussis. Pertussis rates in the United States have been rising and reached a 50-y high of 42,000 cases in 2012. Although pertussis resurgence is not completely understood, we hypothesize that current acellular pertussis (aP) vaccines fail to prevent colonization and transmission. To test our hypothesis, infant baboons were vaccinated at 2, 4, and 6 mo of age with aP or whole-cell pertussis (wP) vaccines and challenged with B. pertussis at 7 mo. Infection was followed by quantifying colonization in nasopharyngeal washes and monitoring leukocytosis and symptoms. Baboons vaccinated with aP were protected from severe pertussis-associated symptoms but not from colonization, did not clear the infection faster than naïve animals, and readily transmitted B. pertussis to unvaccinated contacts. Vaccination with wP induced a more rapid clearance compared with naïve and aP-vaccinated animals. By comparison, previously infected animals were not colonized upon secondary infection. Although all vaccinated and previously infected animals had robust serum antibody responses, we found key differences in T-cell immunity. Previously infected animals and wP-vaccinated animals possess strong B. pertussis-specific T helper 17 (Th17) memory and Th1 memory, whereas aP vaccination induced a Th1/Th2 response instead. The observation that aP, which induces an immune response mismatched to that induced by natural infection, fails to prevent colonization or transmission provides a plausible explanation for the resurgence of pertussis and suggests that optimal control of pertussis will require the development of improved vaccines.", "title": "Acellular pertussis vaccines protect against disease but fail to prevent infection and transmission in a nonhuman primate model." } ]

[ { "docid": "29023309", "text": "Salmonella typhimurium causes a localized enteric infection in immunocompetent individuals, whereas HIV-infected individuals develop a life-threatening bacteremia. Here we show that simian immunodeficiency virus (SIV) infection results in depletion of T helper type 17 (TH17) cells in the ileal mucosa of rhesus macaques, thereby impairing mucosal barrier functions to S. typhimurium dissemination. In SIV-negative macaques, the gene expression profile induced by S. typhimurium in ligated ileal loops was dominated by TH17 responses, including the expression of interleukin-17 (IL-17) and IL-22. TH17 cells were markedly depleted in SIV-infected rhesus macaques, resulting in blunted TH17 responses to S. typhimurium infection and increased bacterial dissemination. IL-17 receptor–deficient mice showed increased systemic dissemination of S. typhimurium from the gut, suggesting that IL-17 deficiency causes defects in mucosal barrier function. We conclude that SIV infection impairs the IL-17 axis, an arm of the mucosal immune response preventing systemic microbial dissemination from the gastrointestinal tract.", "title": "Simian immunodeficiency virus–induced mucosal interleukin-17 deficiency promotes Salmonella dissemination from the gut" } ]

[ { "docid": "8300657", "text": "Human and simian immunodeficiency virus (HIV and SIV) replicate optimally in activated memory CD4(+) T cells, a cell type that is abundant in the intestine. SIV infection of rhesus monkeys resulted in profound and selective depletion of CD4+ T cells in the intestine within days of infection, before any such changes in peripheral lymphoid tissues. The loss of CD4+ T cells in the intestine occurred coincident with productive infection of large numbers of mononuclear cells at this site. The intestine appears to be a major target for SIV replication and the major site of CD4+ T cell loss in early SIV infection.", "title": "Gastrointestinal tract as a major site of CD4+ T cell depletion and viral replication in SIV infection." }, { "docid": "1071991", "text": "Live attenuated simian immunodeficiency virus (SIV) vaccines (LAVs) remain the most efficacious of all vaccines in nonhuman primate models of HIV and AIDS, yet the basis of their robust protection remains poorly understood. Here we show that the degree of LAV-mediated protection against intravenous wild-type SIVmac239 challenge strongly correlates with the magnitude and function of SIV-specific, effector-differentiated T cells in the lymph node but not with the responses of such T cells in the blood or with other cellular, humoral and innate immune parameters. We found that maintenance of protective T cell responses is associated with persistent LAV replication in the lymph node, which occurs almost exclusively in follicular helper T cells. Thus, effective LAVs maintain lymphoid tissue-based, effector-differentiated, SIV-specific T cells that intercept and suppress early wild-type SIV amplification and, if present in sufficient frequencies, can completely control and perhaps clear infection, an observation that provides a rationale for the development of safe, persistent vectors that can elicit and maintain such responses.", "title": "Lymph node T cell responses predict the efficacy of live attenuated SIV vaccines" }, { "docid": "798152", "text": "Analysis of serum samples from 100 wild-caught or colony-born Sykes' monkeys (Cercopithecus mitis) in Kenya revealed that 59 animals had antibodies cross-reactive to human immunodeficiency virus type 2 (HIV-2) and to simian immunodeficiency viruses (SIVs). A lentivirus, designated SIVsyk, was isolated from five of six seropositive asymptomatic Sykes' monkeys, but in four cases isolation was possible only after depletion of CD8+ lymphocytes and cocultivation of the CD4(+)-enriched cell population with peripheral blood mononuclear cells from seronegative Sykes' monkeys. SIVsyk resembled other SIVs and HIVs morphologically, had an Mg2(+)-dependent reverse transcriptase enzyme, and replicated in and was cytopathic for CEMx174 and Sup-T1 cells. SIVsyk differred substantially from other SIVs, however, in that it failed to replicate in normal human, mangabey, and macaque peripheral blood mononuclear cells and serum from seropositive Sykes' monkeys immunoprecipitated env antigens from HIV-1 as well as from HIV-2, SIVsmm, and SIVagm. These data demonstrate a high prevalence of natural infection in Sykes' monkeys in Kenya with a lentivirus that appears to be unique with respect to its host range and antigenic cross-reactivity.", "title": "Isolation from African Sykes' monkeys (Cercopithecus mitis) of a lentivirus related to human and simian immunodeficiency viruses." }, { "docid": "44737533", "text": "METHODS To define potential common features of simian immunodeficiency virus (SIV) infections in different naturally infected host species, we compared the dynamics of viral replication in 31 African green monkeys (10 sabeus, 15 vervets and seven Caribbean AGMs), 14 mandrills and three sooty mangabeys (SMs) that were experimentally infected with their species-specific viruses. \n RESULTS After infection, these SIVs replicated rapidly reaching viral loads (VLs) of 10(5)-10(9) copies/ml of plasma between days 9-14 post-infection (p.i). Set point viremia was established between days 42 and 60 p.i., with levels of approximately 10(5)-10(6) copies/ml in SM and mandrills, and lower levels (10(3)-10(5) copies/ml) in AGMs. VL during the chronic phase did not correlate with viral genome structure: SIVmnd-2 (a vpx-containing virus) and SIVmnd-1 (which does not contain vpu or vpx) replicated to similar levels in mandrills. VL was dependent on virus strain: vervets infected with three different viral strains showed different patterns of viral replication. The pattern of viral replication of SIVagm.sab, which uses both CCR5 and CXCR4 co-receptors was similar to those of the other viruses. \n CONCLUSIONS Our results show a common pattern of SIV replication in naturally and experimentally infected hosts. This is similar overall to that observed in pathogenic SIV infection of macaques. This result indicates that differences in clinical outcome between pathogenic and non-pathogenic infections rely on host responses rather than the characteristics of the virus itself.", "title": "Simian immunodeficiency viruses replication dynamics in African non-human primate hosts: common patterns and species-specific differences." }, { "docid": "20357868", "text": "Primary simian immunodeficiency virus (SIV) isolated from sooty mangabey (SIVsm [n = 6]), stumptail (SIVstm [n = 1]), mandrill (SIVmnd [n = 1]), and African green (SIVagm [n = 1]) primates were examined for their ability to infect human cells and for their coreceptor requirements. All isolates infected human peripheral blood mononuclear cells (PBMCs) from a CCR5(+/+) donor, and seven of eight isolates tested also infected CCR5(-/-) PBMCs. Analysis of coreceptor utilization using GHOST and U87 cell lines revealed that all of the isolates tested used CCR5 and the orphan receptors STRL33 and GPR15. Coreceptors such as CCR2b, CCR3, CCR8, and CX3CR1 were also utilized by some primary SIV isolates. More importantly, we found that CXCR4 was used as a coreceptor by the SIVstm, the SIVagm, and four of the SIVsm isolates in GHOST and U87 cells. These data suggest that primary SIV isolates from diverse primate species can utilize CXCR4 for viral entry, similar to what has been described for human immunodeficiency viruses.", "title": "Simian immunodeficiency viruses of diverse origin can use CXCR4 as a coreceptor for entry into human cells." }, { "docid": "22705234", "text": "The African green monkey (AGM) is one of many African species endemically infected with simian immunodeficiency virus (SIV). Like the other natural hosts, AGMs do not succumb to AIDS and understanding the basis for this resistance to disease progression would be of enormous theoretical and practical importance. Early efforts by our group that concentrated on identifying immune mechanisms presumed to keep the virus under control failed to find any obvious candidates. The presumption of virus control was invalidated by the finding that SIVagm replicates in AGMs with the same vigor as HIV-1 does in humans. Focus therefore shifted to identifying possible immunopathologic features present in disease susceptible hosts but absent in the AGM natural host. The apparent immunologic tolerance of AGMs to the SIVagm core protein led to the development of a hypothesis implicating anti-Gag antibodies in the formation of immune complexes, virus trapping in the lymph nodes and immune dysfunction. The idea proved difficult to test in vivo and present work focuses on the possibility that Gag tolerance at the T-cell level plays an important role in preventing the catastrophic demise of the immune system characteristic of immunodeficiency virus infection of the heterologous primate host.", "title": "The role of the immune response during SIVagm infection of the African green monkey natural host." }, { "docid": "21274496", "text": "Simian immunodeficiency virus (SIV) naturally infects non-human primates in Africa. To date, 40 SIVs have been described both in natural hosts and in heterologous species. These viruses are highly diverse and the majority cluster in 6 relatively equidistant phylogenetic lineages. At least 8 SIVs are currently considered as recombinant viruses, based on different clustering patterns in different genomic regions. Only three types of genomes are known, based on the number of accessory genes: vpr-containing genomes, vpr-vpx containing genomes and vpr-vpu-containing genomes. vpx resulted by a duplication of the vpr gene following non-homologous recombination and is characteristic of SIVs infecting the Papionini tribe of monkeys and HIV-2 in humans. vpu is characteristic of SIVcpz and HIV-1 and may have originated from a recombination involving SIVs from cercopitecini monkeys. SIV seems to be non-pathogenic in the vast majority of natural hosts in spite of a high levels of viral replication. This is probably a consequence of virus-host adaptation, in which the incubation period of the disease generally exceeds the life span of the African primate host. SIVs also have a high propensity for cross-species transmission. In the new host, the outcome may vary from inapparent infection to highly pathogenic, the former being reported for African monkeys, whereas the latter being observed in macaques and humans. The high diversity of SIVs was generated by a high mutation rate due to a low fidelity of the reverse-transcriptase and active viral and host cell turnover, host-dependent evolution and recombination. Cross-species transmission is not rare, however preferential host switching may drive the majority of cross-species transmissions. Numerous SIVs tested so far are able to grow in vitro on human PBMC, therefore it has been postulated that SIV represents a threat for infection of humans in Central Africa and that AIDS is a zoonosis. However, although the simian origin of the two HIV types is broadly acknowledged, there are no data that AIDS is acquired like a zoonosis. SIV may undergo adaptation in the new human host in order to emerge in the general population. The study of SIV in their natural hosts should provide important clues to the real threat to human populations and also elucidate the mechanisms associated with a long-term persistent viral infection without clinical consequences for the host.", "title": "The history of SIVS and AIDS: epidemiology, phylogeny and biology of isolates from naturally SIV infected non-human primates (NHP) in Africa." }, { "docid": "42065070", "text": "Early events during human immunodeficiency virus infections are considered to reflect the capacity of the host to control infection. We have studied early virus and host parameters during the early phase of simian immunodeficiency virus SIVmnd-1 nonpathogenic infection in its natural host, Mandrillus sphinx. Four mandrills were experimentally infected with a primary SIVmnd-1 strain derived from a naturally infected mandrill. Two noninfected control animals were monitored in parallel. Blood and lymph nodes were collected at three time points before infection, twice a week during the first month, and at days 60, 180, and 360 postinfection (p.i.). Anti-SIVmnd-1 antibodies were detected starting from days 28 to 32 p.i. Neither elevated temperature nor increased lymph node size were observed. The viral load in plasma peaked between days 7 to 10 p.i. (2 x 10(6) to 2 x 10(8) RNA equivalents/ml). Viremia then decreased 10- to 1,000-fold, reaching the viral set point between days 30 to 60 p.i. The levels during the chronic phase of infection were similar to that in the naturally infected donor mandrill (2 x 10(5) RNA equivalents/ml). The CD4(+) cell numbers and percentages in blood and lymph nodes decreased slightly (<10%) during primary infection, and CD8(+) cell numbers increased transiently. All values returned to preinfection infection levels by day 30 p.i. CD8(+) cell numbers or percentages, in peripheral blood and lymph nodes, did not increase during the 1 year of follow-up. In conclusion, SIVmnd-1 has the capacity for rapid and extensive replication in mandrills. Despite high levels of viremia, CD4(+) and CD8(+) cell numbers remained stable in the post-acute phase of infection, raising questions regarding the susceptibility of mandrill T cells to activation and/or cell death in response to SIVmnd-1 infection in vivo.", "title": "High levels of viral replication contrast with only transient changes in CD4(+) and CD8(+) cell numbers during the early phase of experimental infection with simian immunodeficiency virus SIVmnd-1 in Mandrillus sphinx." }, { "docid": "22159299", "text": "Salmonella enterica serovar Typhimurium (S. Typhimurium) is a facultative intracellular pathogen that causes disease in a variety of hosts. S. Typhimurium actively invade host cells and typically reside within a membrane-bound compartment called the Salmonella-containing vacuole (SCV). The bacteria modify the fate of the SCV using two independent type III secretion systems (TTSS). TTSS are known to damage eukaryotic cell membranes and S. Typhimurium has been suggested to damage the SCV using its Salmonella pathogenicity island (SPI)-1 encoded TTSS. Here we show that this damage gives rise to an intracellular bacterial population targeted by the autophagy system during in vitro infection. Approximately 20% of intracellular S. Typhimurium colocalized with the autophagy marker GFP-LC3 at 1 h postinfection. Autophagy of S. Typhimurium was dependent upon the SPI-1 TTSS and bacterial protein synthesis. Bacteria targeted by the autophagy system were often associated with ubiquitinated proteins, indicating their exposure to the cytosol. Surprisingly, these bacteria also colocalized with SCV markers. Autophagy-deficient (atg5-/-) cells were more permissive for intracellular growth by S. Typhimurium than normal cells, allowing increased bacterial growth in the cytosol. We propose a model in which the host autophagy system targets bacteria in SCVs damaged by the SPI-1 TTSS. This serves to retain intracellular S. Typhimurium within vacuoles early after infection to protect the cytosol from bacterial colonization. Our findings support a role for autophagy in innate immunity and demonstrate that Salmonella infection is a powerful model to study the autophagy process.", "title": "Autophagy controls Salmonella infection in response to damage to the Salmonella-containing vacuole." }, { "docid": "20864487", "text": "Cytotoxic T-lymphocyte (CTL) responses to human immunodeficiency virus arise early after infection, but ultimately fail to prevent progression to AIDS. Human immunodeficiency virus may evade the CTL response by accumulating amino-acid replacements within CTL epitopes. We studied 10 CTL epitopes during the course of simian immunodeficiency virus disease progression in three related macaques. All 10 of these CTL epitopes accumulated amino-acid replacements and showed evidence of positive selection by the time the macaques died. Many of the amino-acid replacements in these epitopes reduced or eliminated major histocompatibility complex class I binding and/or CTL recognition. These findings strongly support the CTL 'escape' hypothesis.", "title": "Virus-specific cytotoxic T-lymphocyte responses select for amino-acid variation in simian immunodeficiency virus Env and Nef" }, { "docid": "37444589", "text": "Although 13 years have passed since identification of human immunodeficiency virus-1 (HIV-1) as the cause of AIDS, we do not yet know how HIV kills its primary target, the T cell that carries the CD4 antigen. We and others have shown an increase in the percentage of apoptotic cells among circulating CD4+ (and CD8+) T cells of HIV-seropositive individuals and an increase in frequency of apoptosis with disease progression. However, it is not known if this apoptosis occurs in infected or uninfected T cells. We show here, using in situ labelling of lymph nodes from HIV-infected children and SIV-infected macaques, that apoptosis occurs predominantly in bystander cells and not in the productively infected cells themselves. These data have implications for pathogenesis and therapy, namely, arguing that rational drug therapy may involve combination agents targeting viral replication in infected cells and apoptosis of uninfected cells.", "title": "Apoptosis occurs predominantly in bystander cells and not in productively infected cells of HIV- and SIV-infected lymph nodes" }, { "docid": "13398997", "text": "The CD28/cytotoxic T-lymphocyte antigen 4 (CTLA-4)blocker belatacept selectively inhibits alloreactive T cell responses but is associated with a high incidence of acute rejection following renal transplantation,which led us to investigate the etiology of belatacept–resistant graft rejection. T cells can differentiate into functionally distinct subsets of memory T cellsthat collectively enable protection against diverse classes of pathogens and can cross-react with allogeneicantigen and mediate graft rejection. T helper 17(Th17) cells are a pro-inflammatory CD4+ lineage that provides immunity to pathogens and are pathogenic in autoimmune disease. We found that T helper 1 (Th1)and Th17 memory compartments contained a similar frequency of divided cells following allogeneic stimulation. Compared to Th1 cells, Th17 memory cells expressed significantly higher levels of the coinhibitory molecule CTLA-4. Stimulation in the presence of belatacept inhibited Th1 responses but augmented Th17 cells due to greater sensitivity to coinhibition by CTLA-4. Th17 cells from renal transplant recipients were resistant to ex vivo CD28/CTLA-4 blockade with belatacept, and an elevated frequency of Th17 memory cells was associated with acute rejection during belatacept therapy. These data highlight important differences in costimulatory and coinhibitory requirements of CD4+ memory subsets, and demonstrate that the heterogeneity of pathogen-derived memory has implications for immunomodulation strategies.", "title": "High CTLA-4 expression on Th17 cells results in increased sensitivity to CTLA-4 coinhibition and resistance to belatacept." }, { "docid": "11921405", "text": "The gut mucosal epithelium separates the host from the microbiota, but enteropathogens such as Salmonella Typhimurium (S.Tm) can invade and breach this barrier. Defenses against such acute insults remain incompletely understood. Using a murine model of Salmonella enterocolitis, we analyzed mechanisms limiting pathogen loads in the epithelium during early infection. Although the epithelium-invading S.Tm replicate initially, this intraepithelial replicative niche is restricted by expulsion of infected enterocytes into the lumen. This mechanism is compromised if inflammasome components (NAIP1-6, NLRC4, caspase-1/-11) are deleted, or ablated specifically in the epithelium, resulting in ∼100-fold higher intraepithelial loads and accelerated lymph node colonization. Interestingly, the cytokines downstream of inflammasome activation, interleukin (IL)-1α/β and IL-18, appear dispensable for epithelial restriction of early infection. These data establish the role of an epithelium-intrinsic inflammasome, which drives expulsion of infected cells to restrict the pathogen's intraepithelial proliferation. This may represent a general defense mechanism against mucosal infections.", "title": "Epithelium-intrinsic NAIP/NLRC4 inflammasome drives infected enterocyte expulsion to restrict Salmonella replication in the intestinal mucosa." }, { "docid": "35651106", "text": "Efficient T cell activation requires both TCR signals and costimulatory signals. CD28 is one of the molecules that provide costimulatory signals for T cells. We used mice deficient in CD28 expression (CD28-/- mice) to analyze the role of CD28 in the immune response against the intracellular bacterium Salmonella typhimurium, the causative agent of murine typhoid fever. CD28-/- mice were highly susceptible to infection with wild-type S. typhimurium and even failed to control infection with attenuated aroA- S. typhimurium. More detailed analysis revealed that CD28-/- animals did not mount a T-dependent Ab response and were highly impaired in the production of IFN-gamma. Thus, CD28 cosignaling is crucial for immunity against S. typhimurium. To our knowledge, this is the first report describing an essential role for CD28 in protective immunity against an intracellular microbial pathogen.", "title": "Critical role of CD28 in protective immunity against Salmonella typhimurium." }, { "docid": "11233339", "text": "T-helper 17 (Th17) cells are characterized by producing interleukin-17 (IL-17, also called IL-17A), IL-17F, IL-21, and IL-22 and potentially TNF- α and IL-6 upon certain stimulation. IL-23, which promotes Th17 cell development, as well as IL-17 and IL-22 produced by the Th17 cells plays essential roles in various inflammatory diseases, such as experimental autoimmune encephalomyelitis, rheumatoid arthritis, colitis, and Concanavalin A-induced hepatitis. In this review, we summarize the characteristics of the functional role of Th17 cells, with particular focus on the Th17 cell-related cytokines such as IL-17, IL-22, and IL-23, in mouse models and human inflammatory diseases.", "title": "Pivotal Roles of T-Helper 17-Related Cytokines, IL-17, IL-22, and IL-23, in Inflammatory Diseases" }, { "docid": "18546584", "text": "CD4(+) helper T (Th) cells play a crucial role in the delicate balance between host defense and autoimmune disease. Two important populations of helper T cells are the proinflammatory, interleukin-17 (IL-17)-producing (Th17) cells and the anti-inflammatory forkhead box P3-positive (FoxP3(+)) T regulatory (Treg) cells. Here we show that all-trans retinoic acid (ATRA) and other agonists of the retinoic acid receptor alpha (RARalpha) inhibit the formation of Th17 cells and promote FoxP3 expression. Conversely, inhibition of retinoic acid signaling constrains transforming growth factor beta (TGF-beta1) induction of FoxP3. The effect of ATRA is mediated independently of IL-2, signal transducer and activator of transcription 5 (Stat5) and Stat3, representing a novel mechanism for the induction of FoxP3 in CD4 T cells. As previous studies have shown that vitamin A derivatives are protective in animal models of autoimmune disease, the current data suggest a previously unrecognized role for RARalpha in the regulation of CD4(+) T-cell differentiation and provide a mechanism for the anti-inflammatory effects of retinoic acid.", "title": "Retinoic acid inhibits Th17 polarization and enhances FoxP3 expression through a Stat-3/Stat-5 independent signaling pathway." }, { "docid": "19005293", "text": "Inflammation induced by recognition of pathogen-associated molecular patterns markedly affects subsequent adaptive responses. We asked whether the adaptive immune system can also affect the character and magnitude of innate inflammatory responses. We found that the response of memory, but not naive, CD4+ T cells enhances production of multiple innate inflammatory cytokines and chemokines (IICs) in the lung and that, during influenza infection, this leads to early control of virus. Memory CD4+ T cell–induced IICs and viral control require cognate antigen recognition and are optimal when memory cells are either T helper type 1 (TH1) or TH17 polarized but are independent of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) production and do not require activation of conserved pathogen recognition pathways. This represents a previously undescribed mechanism by which memory CD4+ T cells induce an early innate response that enhances immune protection against pathogens.", "title": "Memory CD4+ T cells induce innate responses independently of pathogen" }, { "docid": "51952430", "text": "The toll-like receptor (TLR) and interleukin (IL)-1 family of receptors share several signaling components, including the most upstream adapter, MyD88. We previously reported the discovery of B cell adapter for phosphoinositide 3-kinase (BCAP) as a novel toll-IL-1 receptor homology domain-containing adapter that regulates inflammatory responses downstream of TLR signaling. Here we find that BCAP plays a critical role downstream of both IL-1 and IL-18 receptors to regulate T helper (Th) 17 and Th1 cell differentiation, respectively. Absence of T cell intrinsic BCAP did not alter development of naturally arising Th1 and Th17 lineages but led to defects in differentiation to pathogenic Th17 lineage cells. Consequently, mice that lack BCAP in T cells had reduced susceptibility to experimental autoimmune encephalomyelitis. More importantly, we found that BCAP is critical for IL-1R-induced phosphoinositide 3-kinase-Akt-mechanistic target of rapamycin (mTOR) activation, and minimal inhibition of mTOR completely abrogated IL-1β-induced differentiation of pathogenic Th17 cells, mimicking BCAP deficiency. This study establishes BCAP as a critical link between IL-1R and the metabolic status of activated T cells that ultimately regulates the differentiation of inflammatory Th17 cells.", "title": "BCAP links IL-1R to the PI3K–mTOR pathway and regulates pathogenic Th17 cell differentiation" }, { "docid": "8063697", "text": "Pertussis is a highly contagious respiratory illness caused by the bacterial pathogen Bordetella pertussis. Pertussis rates in the United States have been rising and reached a 50-y high of 42,000 cases in 2012. Although pertussis resurgence is not completely understood, we hypothesize that current acellular pertussis (aP) vaccines fail to prevent colonization and transmission. To test our hypothesis, infant baboons were vaccinated at 2, 4, and 6 mo of age with aP or whole-cell pertussis (wP) vaccines and challenged with B. pertussis at 7 mo. Infection was followed by quantifying colonization in nasopharyngeal washes and monitoring leukocytosis and symptoms. Baboons vaccinated with aP were protected from severe pertussis-associated symptoms but not from colonization, did not clear the infection faster than naïve animals, and readily transmitted B. pertussis to unvaccinated contacts. Vaccination with wP induced a more rapid clearance compared with naïve and aP-vaccinated animals. By comparison, previously infected animals were not colonized upon secondary infection. Although all vaccinated and previously infected animals had robust serum antibody responses, we found key differences in T-cell immunity. Previously infected animals and wP-vaccinated animals possess strong B. pertussis-specific T helper 17 (Th17) memory and Th1 memory, whereas aP vaccination induced a Th1/Th2 response instead. The observation that aP, which induces an immune response mismatched to that induced by natural infection, fails to prevent colonization or transmission provides a plausible explanation for the resurgence of pertussis and suggests that optimal control of pertussis will require the development of improved vaccines.", "title": "Acellular pertussis vaccines protect against disease but fail to prevent infection and transmission in a nonhuman primate model." } ]

[ { "docid": "25079962", "text": "CONTEXT Delayed cerebral vasospasm causes permanent neurological deficits or death in at least 15% of patients following otherwise successful treatment for ruptured intracranial aneurysm. Decreased bioavailability of nitric oxide has been associated with the development of cerebral vasospasm. \n OBJECTIVE To determine whether infusions of nitrite will prevent delayed cerebral vasospasm. \n DESIGN, SETTING, AND SUBJECTS A total of 14 anesthetized cynomolgus monkeys had an autologous blood clot placed around the right middle cerebral artery. Cerebral arteriography was performed before clot placement and on days 7 and 14 to assess vasospasm. The study was conducted from August 2003 to February 2004. \n INTERVENTIONS A 90-mg sodium nitrite intravenous solution infused over 24 hours plus a 45-mg sodium nitrite bolus daily (n = 3); a 180-mg sodium nitrite intravenous solution infused over 24 hours (n = 3); or a control saline solution infusion (n = 8). Each was infused continuously for 14 days. \n MAIN OUTCOME MEASURES Nitrite, S-nitrosothiol, and methemoglobin levels in blood and cerebrospinal fluid and degree of arteriographic vasospasm. \n RESULTS In control monkeys, mean (SD) cerebrospinal fluid nitrite levels decreased from 3.1 (1.5) micromol/L to 0.4 (0.1) micromol/L at day 7 and to 0.4 (0.4) micromol/L at day 14 (P = .03). All 8 control monkeys developed significant vasospasm of the right middle cerebral artery, which was complicated by stroke and death in 1 animal. Sodium nitrite infusions increased the nitrite and methemoglobin levels (<2.1% of total hemoglobin) in the blood and cerebrospinal fluid without evoking systemic hypotension. Nitrite infusion prevented development of vasospasm (no animals developed significant vasospasm; mean [SD] reduction in right middle cerebral artery area on day 7 after subarachnoid hemorrhage of 8% [9%] in nitrite-treated monkeys vs 47% [5%] in saline-treated controls; P<.001). There was a negative correlation between the concentration of nitrite in cerebrospinal fluid and the degree of cerebral vasospasm (P<.001). Pharmacological effects of nitrite infusion were also associated with the formation of S-nitrosothiol in cerebrospinal fluid. There was no clinical or pathological evidence of nitrite toxicity. \n CONCLUSION Subacute sodium nitrite infusions prevented delayed cerebral vasospasm in a primate model of subarachnoid hemorrhage.", "title": "Nitrite infusions to prevent delayed cerebral vasospasm in a primate model of subarachnoid hemorrhage." } ]

[ { "docid": "23100962", "text": "Besides synthesizing nitric oxide (NO), purified neuronal NO synthase (nNOS) can produce superoxide (.O2-) at lower L-Arg concentrations. By using electron paramagnetic resonance spin-trapping techniques, we monitored NO and .O2- formation in nNOS-transfected human kidney 293 cells. In control transfected cells, the Ca2+ ionophore A23187 triggered NO generation but no .O2- was seen. With cells in L-Arg-free medium, we observed .O2- formation that increased as the cytosolic L-Arg levels decreased, while NO generation declined. .O2- formation was virtually abolished by the specific NOS blocker, N-nitro-L-arginine methyl ester (L-NAME). Nitrotyrosine, a specific nitration product of peroxynitrite, accumulated in L-Arg-depleted cells but not in control cells. Activation by A23187 was cytotoxic to L-Arg-depleted, but not to control cells, with marked lactate dehydrogenase release. The cytotoxicity was largely prevented by either superoxide dismutase or L-NAME. Thus, with reduced L-Arg availability NOS elicits cytotoxicity by generating .O2- and NO that interact to form the potent oxidant peroxynitrite. Regulating arginine levels may provide a therapeutic approach to disorders involving .O2-/NO-mediated cellular injury.", "title": "Nitric oxide synthase generates superoxide and nitric oxide in arginine-depleted cells leading to peroxynitrite-mediated cellular injury." }, { "docid": "24338780", "text": "BACKGROUND Interferon-gamma (IFN-gamma) is an essential cytokine in the regulation of inflammatory responses in autoimmune diseases. Little is known about its role in inflammatory heart disease. \n METHODS AND RESULTS We showed that IFN-gamma receptor-deficient mice (IFN-gammaR(-/-)) on a BALB/c background immunized with a peptide derived from cardiac alpha-myosin heavy chain develop severe myocarditis with high mortality. Although myocarditis subsided in wild-type mice after 3 weeks, IFN-gammaR(-/-) mice showed persistent disease. The persistent inflammation was accompanied by vigorous in vitro CD4 T-cell responses and impaired inducible nitric oxide synthase expression, together with evidence of impaired nitric oxide production in IFN-gammaR(-/-) hearts. Treatment of wild-type mice with the nitric oxide synthetase inhibitor N:-nitro-l-arginine-methyl-ester enhanced in vitro CD4 T-cell proliferation and prevented healing of myocarditis. \n CONCLUSIONS Our data provide evidence that IFN-gamma protects mice from lethal autoimmune myocarditis by inducing the expression of inducible nitric oxide synthase followed by the downregulation of T-cell responses.", "title": "Lethal autoimmune myocarditis in interferon-gamma receptor-deficient mice: enhanced disease severity by impaired inducible nitric oxide synthase induction." }, { "docid": "46743299", "text": "Chronic exercise upregulates endothelial nitric oxide synthase (eNOS) gene expression. Whether the expression of inducible nitric oxide synthase (iNOS) is affected by exercise is unknown. We therefore investigated the effects of chronic exercise on iNOS and eNOS expression in isolated rat aortic endothelial and smooth muscle cells separately. Five-week-old male Wistar rats were randomly divided into control and exercise groups. After 10 weeks of running training, animals were sacrificed under ether anesthesia. The standard curve quantitative competitive reverse transcriptase-polymerase chain reaction method was used to quantify NOS mRNA expression in isolated endothelial/smooth muscle cells. To evaluate the functional role of iNOS, we examined phenylephrine-induced vascular responses with or without pretreatment with aminoguanidine. We found that (1) expression of iNOS and eNOS mRNA in endothelial cells was increased by chronic exercise and (2) chronic exercise blunted phenylephrine-induced vascular responses, probably by increasing NO release via iNOS. Our results show that chronic exercise increases both iNOS and eNOS gene expression in endothelium. These alterations may be partially responsible for the change in vascular response after exercise.", "title": "Chronic Exercise Increases Both Inducible and Endothelial Nitric Oxide Synthase Gene Expression in Endothelial Cells of Rat Aorta" }, { "docid": "14474178", "text": "The objective of the present study was to determine if chicken melanoma-differentiation-associated gene 5 (MDA5) senses infectious bursal disease virus infection to induce innate immunity that bridges to adaptive immunity. During IBDV infection in HD11 cells, IBDV titers and RNA loads increased up to 3.4 × 107 plaque-forming units (PFU)/mL and 1114 ng/µL, respectively, at 24 hours postinfection (hpi). IBDV infection in HD11 cells induced significantly upregulated (p < 0.05) expression levels of chicken MDA5 (59-fold), interferon-β (IFN-β) (693-fold), dsRNA-dependent protein kinase (PKR) (4-fold), 2’, 5’-oligoadenylate synthetase (OAS) (286-fold), myxovirus resistance gene (Mx) (22-fold), interleukin-1β (IL-1β) (5-fold), IL-6 (146-fold), IL-8 (4-fold), IL-10 (4-fold), inducible nitric oxide synthase (iNOS) (15-fold), and major histocompatibility complex class I (MHC class I) (4-fold). Nitric oxide production in the culture supernatants increased significantly (p < 0.05) up to 6.5 μM at 24 hpi. The expressed chMDA5 and IBDV-derived dsRNA were localized in the cytoplasm of HD11 cells during IBDV infection. ChMDA5-knockdown HD11 cells had significantly higher (p < 0.05) IBDV RNA loads at 24 hpi and significantly lower (p < 0.05) nitric oxide production and expression levels of chicken MDA5, IFN-β, PKR, OAS, Mx, IL-1β, IL-6, IL-8, IL-12(p40), IL-18, IL-10, iNOS, MHC class I and CD86 at 24 hpi. In addition, chMDA5 overexpression in HD11 cells resulted in significantly reduced (p < 0.05) IBDV titers and RNA loads and significantly increased (p < 0.05) nitric oxide production at 16 and 24 hpi. It also resulted in significantly higher (p < 0.05) expression levels of chicken MDA5, IFN-β, PKR, OAS, Mx, IL-1β, IL-6, IL-8, IL-12(p40), IL-10 and iNOS at 2 hpi. In conclusion, the results indicate that chMDA5 senses IBDV infection in chicken macrophages, and this is associated with IBDV-induced expression of IFN-β and initiation of an innate immune response that in turn activates the adaptive immune response and limits IBDV replication.", "title": "Role of chicken melanoma differentiation-associated gene 5 in induction and activation of innate and adaptive immune responses to infectious bursal disease virus in cultured macrophages" }, { "docid": "7155555", "text": "Listeria monocytogenes is widely used as a model to study immune responses against intracellular bacteria. It has been shown that neutrophils and macrophages play an important role to restrict bacterial replication in the early phase of primary infection in mice, and that the cytokines interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) are essential for protection. However, the involved signaling pathways and effector mechanisms are still poorly understood. This study investigated mouse strains deficient for the IFN-dependent transcription factors interferon consensus sequence binding protein (ICSBP), interferon regulatory factor (IRF)1 or 2 for their capacity to eliminate Listeria in vivo and in vitro and for production of inducible reactive nitrogen intermediates (RNI) or reactive oxygen intermediates (ROI) in macrophages. ICSBP−/− and to a lesser degree also IRF2−/− mice were highly susceptible to Listeria infection. This correlated with impaired elimination of Listeria from infected peritoneal macrophage (PEM) cultures stimulated with IFN-γ in vitro; in addition these cultures showed reduced and delayed oxidative burst upon IFN-γ stimulation, whereas nitric oxide production was normal. In contrast, mice deficient for IRF1 were not able to produce nitric oxide, but they efficiently controlled Listeria in vivo and in vitro. These results indicate that (a) the ICSBP/IRF2 complex is essential for IFN-γ–mediated protection against Listeria and that (b) ROI together with additional still unknown effector mechanisms may be responsible for the anti-Listeria activity of macrophages, whereas IRF1-induced RNI are not limiting.", "title": "Crucial Role of Interferon Consensus Sequence Binding Protein, but neither of Interferon Regulatory Factor 1 nor of Nitric Oxide Synthesis for Protection Against Murine Listeriosis" }, { "docid": "23122306", "text": "In an experiment to clarify the involvement of oxygen radicals in lung carcinogenesis induced by diesel exhaust particles (DEP), we found that there is a strong relation between lung tumor response and formation of 8-hydroxydeoxyguanosine (8-OHdG) in lung DNA of mice administered DEP by repeated intratracheal instillation. Repeated intratracheal instillation of DEP also induced the activity of cytochrome P-450 reductase in the lungs as a representative enzyme of superoxide generation, and two types of nitric oxide (NO) synthase, cNOS and iNOS, in the lungs. On the other hand, activities of CuZn-superoxide dismutase (SOD) and Mn-SOD antioxidant enzymes were depressed by the instillation of DEP. These results suggest that generation of superoxide, hydroxyI radical, and nitric oxide are increased in epithelial cells in airways, and that the increased superoxide and nitric oxide react very easily to produce peroxynitrite (ONOO(-)). The peroxynitrite also produce hydroxyI radical. The hydroxyl radical may play an important role in carcinogenesis by DEP.", "title": "Lung Carcinogenesis by Diesel Exhaust Particles and the Carcinogenic Mechanism Via Active Oxygens." }, { "docid": "10697096", "text": "BACKGROUND The purpose of this study was to test the hypothesis that vasodilator responses of porcine coronary resistance arteries are increased by exercise training. \n METHODS AND RESULTS Yucatan miniature swine were randomly divided into groups of exercise-trained (ET) and sedentary (SED) control pigs. ET pigs were placed on a progressive treadmill training program lasting 16 to 20 weeks, and SED pigs remained inactive during the same time period. Coronary resistance arteries 64 to 157 microns in diameter were isolated for in vitro evaluation of relaxation responses to the endothelium-independent dilators sodium nitroprusside (1 x 10(-10) to 1 x 10(-4) mol/L) and adenosine (1 x 10(-10) to 1 x 10(-5) mol/L) and to bradykinin (1 x 10(-13) to 3 x 10(-7) mol/L), an endothelium-dependent agent. Relaxation responses to adenosine and sodium nitroprusside were not altered by exercise training. Endothelium-dependent relaxation to bradykinin was enhanced in coronary resistance arteries from ET pigs (IC50: ET, 0.07 +/- 0.02 nmol/L; SED, 1.59 +/- 0.09 nmol/L). To determine whether prostanoids and/or the nitric oxide synthase pathway were involved in the ET-induced changes in bradykinin-induced vasodilation, responses to bradykinin were examined in coronary resistance arteries from both ET and SED pigs in the presence of indomethacin and in the presence of nitro-monomethyl L-arginine (L-NMMA). Both indomethacin and L-NMMA produced significant inhibition of the bradykinin-induced relaxation in vessels from both groups. Despite decreased bradykinin-induced relaxation after indomethacin, bradykinin-induced vasodilation was still enhanced in vessels from the ET group. L-NMMA caused greater inhibition of the bradykinin-induced relaxation in coronary resistance arteries from ET pigs relative to arteries from SED pigs and eliminated the training-induced enhancement of the bradykinin responses. \n CONCLUSIONS These results suggest that exercise training enhances bradykinin-induced vasodilation through increased endothelium-derived relaxing factor/nitric oxide production by the L-arginine/nitric oxide synthase pathway.", "title": "Vasodilator responses of coronary resistance arteries of exercise-trained pigs." }, { "docid": "8536018", "text": "Nitric oxide (NO) was identified as a key player in plant defence responses approximately 20 years ago and a large body of evidence has accumulated since then supporting its role as a signalling molecule. However, there are many discrepancies in current NO detection assays and the enzymatic pathways responsible for its synthesis have yet to be determined. This has provoked strong debates concerning the function of NO in plants, even questioning its existence in planta. Here we gather data obtained using the model pathosystem Arabidopsis/Pseudomonas, which confirms the production of NO during the hypersensitive response and supports is role as a trigger of hypersensitive cell death and a mediator of defence gene expression. Finally, we discuss potential sources of NO synthesis, focusing on the role of nitrite as major substrate for NO production during incompatible interactions.", "title": "Detection and function of nitric oxide during the hypersensitive response in Arabidopsis thaliana: where there's a will there's a way." }, { "docid": "21297708", "text": "1. Nitric oxide (NO) has been suggested as a gastrointestinal neurotransmitter, mediating the gastric receptive relaxation and the relaxation in the peristaltic reflex. The aim of the present study was to measure nerve-induced NO formation in vivo in the gastrointestinal tract. 2. Formation of the nitric oxide oxidation products nitrite and nitrate during vagal nerve stimulation were measured in the anaesthetized rabbit. Microdialysis probes were inserted into the wall of the stomach and proximal colon, and nitrite and nitrate in dialysate measured by capillary electrophoresis. 3. During bilateral vagal nerve stimulation there was an increase in nitrite and nitrate formation at the level of the stomach and in nitrite formation at the level of the colon. This increase was inhibited by intravenous administration of the NO synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME 30 mg kg-1). Furthermore, L-NAME significantly increased nerve-induced gastric and colonic contractions, as well as spontaneous colonic contractions. 4. In summary, we present a new methodological procedure for quantification of small changes in nitric oxide formation in vivo. This study provides evidence that nitric oxide is released in the stomach and colonic wall during vagal nerve activity, at concentrations able to cause inhibition of smooth muscle contractions in vivo.", "title": "Nerve-induced release of nitric oxide in the rabbit gastrointestinal tract as measured by in vivo microdialysis." }, { "docid": "20381484", "text": "S-nitrosylation of proteins by nitric oxide is a major mode of signalling in cells. S-nitrosylation can mediate the regulation of a range of proteins, including prominent nuclear proteins, such as HDAC2 (ref. 2) and PARP1 (ref. 3). The high reactivity of the nitric oxide group with protein thiols, but the selective nature of nitrosylation within the cell, implies the existence of targeting mechanisms. Specificity of nitric oxide signalling is often achieved by the binding of nitric oxide synthase (NOS) to target proteins, either directly or through scaffolding proteins such as PSD-95 (ref. 5) and CAPON. As the three principal isoforms of NOS--neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS)--are primarily non-nuclear, the mechanisms by which nuclear proteins are selectively nitrosylated have been elusive. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is physiologically nitrosylated at its Cys 150 residue. Nitrosylated GAPDH (SNO-GAPDH) binds to Siah1, which possesses a nuclear localization signal, and is transported to the nucleus. Here, we show that SNO-GAPDH physiologically transnitrosylates nuclear proteins, including the deacetylating enzyme sirtuin-1 (SIRT1), histone deacetylase-2 (HDAC2) and DNA-activated protein kinase (DNA-PK). Our findings reveal a novel mechanism for targeted nitrosylation of nuclear proteins and suggest that protein-protein transfer of nitric oxide groups may be a general mechanism in cellular signal transduction.", "title": "GAPDH Mediates Nitrosylation of Nuclear Proteins" }, { "docid": "42873134", "text": "Type 1 and type 2 diabetes are characterized by progressive beta-cell failure. Apoptosis is probably the main form of beta-cell death in both forms of the disease. It has been suggested that the mechanisms leading to nutrient- and cytokine-induced beta-cell death in type 2 and type 1 diabetes, respectively, share the activation of a final common pathway involving interleukin (IL)-1beta, nuclear factor (NF)-kappaB, and Fas. We review herein the similarities and differences between the mechanisms of beta-cell death in type 1 and type 2 diabetes. In the insulitis lesion in type 1 diabetes, invading immune cells produce cytokines, such as IL-1beta, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma. IL-1beta and/or TNF-alpha plus IFN-gamma induce beta-cell apoptosis via the activation of beta-cell gene networks under the control of the transcription factors NF-kappaB and STAT-1. NF-kappaB activation leads to production of nitric oxide (NO) and chemokines and depletion of endoplasmic reticulum (ER) calcium. The execution of beta-cell death occurs through activation of mitogen-activated protein kinases, via triggering of ER stress and by the release of mitochondrial death signals. Chronic exposure to elevated levels of glucose and free fatty acids (FFAs) causes beta-cell dysfunction and may induce beta-cell apoptosis in type 2 diabetes. Exposure to high glucose has dual effects, triggering initially \"glucose hypersensitization\" and later apoptosis, via different mechanisms. High glucose, however, does not induce or activate IL-1beta, NF-kappaB, or inducible nitric oxide synthase in rat or human beta-cells in vitro or in vivo in Psammomys obesus. FFAs may cause beta-cell apoptosis via ER stress, which is NF-kappaB and NO independent. Thus, cytokines and nutrients trigger beta-cell death by fundamentally different mechanisms, namely an NF-kappaB-dependent mechanism that culminates in caspase-3 activation for cytokines and an NF-kappaB-independent mechanism for nutrients. This argues against a unifying hypothesis for the mechanisms of beta-cell death in type 1 and type 2 diabetes and suggests that different approaches will be required to prevent beta-cell death in type 1 and type 2 diabetes.", "title": "Mechanisms of pancreatic beta-cell death in type 1 and type 2 diabetes: many differences, few similarities." }, { "docid": "2533768", "text": "Clinical manifestations of diabetic nephropathy are an expression of diabetic microangiopathy. This review revisits the previously proposed Steno hypothesis and advances our hypothesis that development of endothelial cell dysfunction represents a common pathophysiological pathway of diabetic complications. Specifically, the ability of glucose to scavenge nitric oxide is proposed as the initiation phase of endothelial dysfunction. Gradual accumulation of advanced glycated end products and induction of plasminogen activator inhibitor-1, resulting in the decreased expression of endothelial nitric oxide synthase and reduced generation of nitric oxide, are proposed to be pathophysiologically critical for the maintenance phase of endothelial dysfunction. The proposed conceptual shift toward the role of endothelial dysfunction in diabetic complications may provide new strategies for their prevention.", "title": "Workshop: endothelial cell dysfunction leading to diabetic nephropathy : focus on nitric oxide." }, { "docid": "38944245", "text": "Lung Krüppel-like factor (LKLF/KLF2) is an endothelial transcription factor that is crucially involved in murine vasculogenesis and is specifically regulated by flow in vitro. We now show a relation to local flow variations in the adult human vasculature: decreased LKLF expression was noted at the aorta bifurcations to the iliac and carotid arteries, coinciding with neointima formation. The direct involvement of shear stress in the in vivo expression of LKLF was determined independently by in situ hybridization and laser microbeam microdissection/reverse transcriptase-polymerase chain reaction in a murine carotid artery collar model, in which a 4- to 30-fold induction of LKLF occurred at the high-shear sites. Dissection of the biomechanics of LKLF regulation in vitro demonstrated that steady flow and pulsatile flow induced basal LKLF expression 15- and 36-fold at shear stresses greater than approximately 5 dyne/cm2, whereas cyclic stretch had no effect. Prolonged LKLF induction in the absence of flow changed the expression of angiotensin-converting enzyme, endothelin-1, adrenomedullin, and endothelial nitric oxide synthase to levels similar to those observed under prolonged flow. LKLF repression by siRNA suppressed the flow response of endothelin-1, adrenomedullin, and endothelial nitric oxide synthase (P < 0.05). Thus, we demonstrate that endothelial LKLF is regulated by flow in vivo and is a transcriptional regulator of several endothelial genes that control vascular tone in response to flow.", "title": "Endothelial KLF2 links local arterial shear stress levels to the expression of vascular tone-regulating genes." }, { "docid": "46328296", "text": "Patients with essential hypertension exhibit blunted endothelium-dependent vasodilator responses, which may be largely attributable to reduced bioactivity of nitric oxide (NO). Therefore, we measured the end product of NO, nitrate plus nitrite (nitrogen oxide), and examined the relationship between the degree of hypertension and plasma nitrate plus nitrite levels in patients with essential hypertension. The combined plasma concentration of nitrate plus nitrite, end products of NO metabolism, was reduced in individuals with essential hypertension relative to that in control subjects (15.7+/-1.1 versus 22.8+/-1.4 mmol x L(-1), P<.001); individuals with borderline hypertension showed values that were intermediate between those of the other two groups (18.2+/-1.2 mmol x L(-1), P<.001). The plasma nitrogen oxide concentration showed significant inverse correlations with both systolic and diastolic blood pressures. The basal concentration of nitrogen oxide in the plasma was reduced, at least in the peripheral circulation, in individuals with essential hypertension.", "title": "Reduced plasma concentrations of nitrogen oxide in individuals with essential hypertension." }, { "docid": "7230315", "text": "The high-output pathway of nitric oxide production helps protect mice from infection by several pathogens, including Mycobacterium tuberculosis. However, based on studies of cells cultured from blood, it is controversial whether human mononuclear phagocytes can express the corresponding inducible nitric oxide synthase (iNOS;NOS2). The present study examined alveolar macrophages fixed directly after bronchopulmonary lavage. An average of 65% of the macrophages from 11 of 11 patients with untreated, culture-positive pulmonary tuberculosis reacted with an antibody documented herein to be monospecific for human NOS2. In contrast, a mean of 10% of bronchoalveolar lavage cells were positive from each of five clinically normal subjects. Tuberculosis patients' macrophages displayed diaphorase activity in the same proportion that they stained for NOS2, under assay conditions wherein the diaphorase reaction was strictly dependent on NOS2 expression. Bronchoalveolar lavage specimens also contained NOS2 mRNA. Thus, macrophages in the lungs of people with clinically active Mycobacterium tuberculosis infection often express catalytically competent NOS2.", "title": "Inducible nitric oxide synthase in pulmonary alveolar macrophages from patients with tuberculosis" }, { "docid": "6580081", "text": "Ischemia-reperfusion injury is, at least in part, responsible for the morbidity associated with liver surgery under total vascular exclusion or after liver transplantation. The pathophysiology of hepatic ischemia-reperfusion includes a number of mechanisms that contribute to various degrees in the overall injury. Some of the topics discussed in this review include cellular mechanisms of injury, formation of pro- and anti-inflammatory mediators, expression of adhesion molecules, and the role of oxidant stress during the inflammatory response. Furthermore, the roles of nitric oxide in preventing microcirculatory disturbances and as a substrate for peroxynitrite formation are reviewed. In addition, emerging mechanisms of protection by ischemic preconditioning are discussed. On the basis of current knowledge, preconditioning or pharmacological interventions that mimic these effects have the greatest potential to improve clinical outcome in liver surgery involving ischemic stress and reperfusion.", "title": "Molecular mechanisms of hepatic ischemia-reperfusion injury and preconditioning." }, { "docid": "14711483", "text": "CONTEXT Vaso-occlusion is central to the painful crises and acute and chronic organ damage in sickle cell disease. Abnormal nitric oxide-dependent regulation of vascular tone, adhesion, platelet activation, and inflammation contributes to the pathophysiology of vaso-occlusion. Nitric oxide may have promise as a mechanism-of-disease-based therapy for treatment of vaso-occlusion. \n OBJECTIVE To explore the efficacy and safety of inhaled nitric oxide (INO) for treatment of vaso-occlusive crisis in pediatric patients. \n DESIGN Prospective, double-blind, placebo-controlled, randomized clinical trial with enrollment between September 1999 and October 2001. \n SETTING Urban, tertiary care children's hospital in the United States. \n PARTICIPANTS Twenty patients aged 10 to 21 years with sickle cell disease and severe acute vaso-occlusive crisis. \n INTERVENTION Patients were randomly assigned to receive INO (80 ppm with 21% final concentration of inspired oxygen; n = 10), or placebo (21% inspired oxygen; n = 10) for 4 hours. \n MAIN OUTCOME MEASURES Change in pain at 4 hours of inhalation compared with preinhalation pain, measured on a 10-cm visual analog scale (VAS); secondary outcome measures were pain over 6 hours, parenteral narcotic use over 24 hours, duration of hospitalization, blood pressure, oxygen saturation, and methemoglobin concentration. \n RESULTS Preinhalation VAS pain scores were similar in the INO and placebo groups (P =.80). The decrease in VAS pain scores at 4 hours was 2.0 cm in the INO group and 1.2 cm in the placebo group (P =.37). Repeated-measures analysis of variance for hourly pain scores showed a 1-cm/h greater reduction in the INO group than the placebo group (P =.02). Morphine use over 6 hours was significantly less in the INO group (mean cumulative use, 0.29 vs 0.44 mg/kg; P =.03) but was not different over 4 hours (0.26 vs 0.32 mg/kg; P =.21) or 24 hours (0.63 vs 0.91 mg/kg; P =.15). Duration of hospitalization was 78 and 100 hours in the INO and placebo groups, respectively (P =.19). No INO toxicity was observed. \n CONCLUSIONS Results of this exploratory study suggest that INO may be beneficial for acute vaso-occlusive crisis. These preliminary results warrant further investigation.", "title": "Preliminary assessment of inhaled nitric oxide for acute vaso-occlusive crisis in pediatric patients with sickle cell disease." }, { "docid": "12582729", "text": "BACKGROUND Upregulated by atheroprotective flow, the transcription factor Krüppel-like factor 2 (KLF2) is crucial for maintaining endothelial function. MicroRNAs (miRNAs) are noncoding small RNAs that regulate gene expression at the posttranscriptional level. We examined the role of miRNAs, particularly miR-92a, in the atheroprotective flow-regulated KLF2. \n METHODS AND RESULTS Dicer knockdown increased the level of KLF2 mRNA in human umbilical vein endothelial cells, suggesting that KLF2 is regulated by miRNA. In silico analysis predicted that miR-92a could bind to the 3' untranslated region of KLF2 mRNA. Overexpression of miR-92a decreased the expression of KLF2 and the KLF2-regulated endothelial nitric oxide synthase and thrombomodulin at mRNA and protein levels. A complementary finding is that miR-92a inhibitor increased the mRNA and protein expression of KLF2, endothelial nitric oxide synthase, and thrombomodulin. Subsequent studies revealed that atheroprotective laminar flow downregulated the level of miR-92a precursor to induce KLF2, and the level of this flow-induced KLF2 was reduced by miR-92a precursor. Furthermore, miR-92a level was lower in human umbilical vein endothelial cells exposed to the atheroprotective pulsatile shear flow than under atheroprone oscillatory shear flow. Anti-Ago1/2 immunoprecipitation coupled with real-time polymerase chain reaction revealed that pulsatile shear flow decreased the functional targeting of miR-92a precursor/KLF2 mRNA in human umbilical vein endothelial cells. Consistent with these findings, mouse carotid arteries receiving miR-92a precursor exhibited impaired vasodilatory response to flow. \n CONCLUSIONS Atheroprotective flow patterns decrease the level of miR-92a, which in turn increases KLF2 expression to maintain endothelial homeostasis.", "title": "Flow-Dependent Regulation of Kruppel-Like Factor 2 Is Mediated by MicroRNA-92a." }, { "docid": "15561961", "text": "Hypercholesterolemia is associated with impairments in endothelium-dependent vascular relaxations. Paradoxically, endothelial production of nitrogen oxides is increased in early stages of hypercholesterolemia. Prior work has shown that oxidized low density lipoprotein (LDL) has both stimulatory and inhibitory effects on endothelial nitric oxide synthase expression (eNOS) and has focused on lysophosphatidyl choline (LPC) as a component of oxidized LDL which may modulate this effect. Another biologically active component of oxidized LDL is 13-hydroperoxyoctadecadienoic acid (13-HPODE), an oxidized form of linoleic acid. The purpose of this study was to determine the effect of HPODE on the expression of eNOS in bovine aortic endothelial cells (BAECs). Twenty four hour treatment of endothelial cells with HPODE caused a dose-dependent increase in eNOS mRNA levels as assessed by Northern analysis. The time response studies show that HPODE treatment significantly increased eNOS mRNA levels at 12 and 24 h. Concomitant with the increase in eNOS mRNA levels, 20 microM HPODE treatment significantly increased eNOS protein content and enzyme activity. Nuclear run-on studies indicated that the rate of transcription of eNOS gene was significantly elevated 4 h after HPODE treatment when compared to control cultures. Also, actinomycin D studies demonstrated that the half-life of eNOS mRNA was increased from 6 h to 12 h by HPODE treatment. Thus, HPODE-induced up-regulation of eNOS expression is mediated by both transcriptional and posttranscriptional mechanisms. These observations suggest that endothelial cells may attempt to compensate for oxidative injury by increasing expression of eNOS in early stages of hypercholesterolemia.", "title": "expression by oxidized linoleic" } ]

[ { "docid": "1780819", "text": "BACKGROUND Endometrial cancer incidence is continuing to rise in the wake of the current ageing and obesity epidemics. Much of the risk for endometrial cancer development is influenced by the environment and lifestyle. Accumulating evidence suggests that the epigenome serves as the interface between the genome and the environment and that hypermethylation of stem cell polycomb group target genes is an epigenetic hallmark of cancer. The objective of this study was to determine the functional role of epigenetic factors in endometrial cancer development. \n METHODS AND FINDINGS Epigenome-wide methylation analysis of >27,000 CpG sites in endometrial cancer tissue samples (n = 64) and control samples (n = 23) revealed that HAND2 (a gene encoding a transcription factor expressed in the endometrial stroma) is one of the most commonly hypermethylated and silenced genes in endometrial cancer. A novel integrative epigenome-transcriptome-interactome analysis further revealed that HAND2 is the hub of the most highly ranked differential methylation hotspot in endometrial cancer. These findings were validated using candidate gene methylation analysis in multiple clinical sample sets of tissue samples from a total of 272 additional women. Increased HAND2 methylation was a feature of premalignant endometrial lesions and was seen to parallel a decrease in RNA and protein levels. Furthermore, women with high endometrial HAND2 methylation in their premalignant lesions were less likely to respond to progesterone treatment. HAND2 methylation analysis of endometrial secretions collected using high vaginal swabs taken from women with postmenopausal bleeding specifically identified those patients with early stage endometrial cancer with both high sensitivity and high specificity (receiver operating characteristics area under the curve = 0.91 for stage 1A and 0.97 for higher than stage 1A). Finally, mice harbouring a Hand2 knock-out specifically in their endometrium were shown to develop precancerous endometrial lesions with increasing age, and these lesions also demonstrated a lack of PTEN expression. \n CONCLUSIONS HAND2 methylation is a common and crucial molecular alteration in endometrial cancer that could potentially be employed as a biomarker for early detection of endometrial cancer and as a predictor of treatment response. The true clinical utility of HAND2 DNA methylation, however, requires further validation in prospective studies. Please see later in the article for the Editors' Summary.", "title": "Role of DNA Methylation and Epigenetic Silencing of HAND2 in Endometrial Cancer Development" } ]

[ { "docid": "4767806", "text": "Maintenance and accurate propagation of the genetic material are key features for physiological development and wellbeing. The replication licensing machinery is crucial for replication precision as it ensures that replication takes place once per cell cycle. Thus, the expression status of the components comprising the replication licensing apparatus is tightly regulated to avoid re-replication; a form of replication stress that leads to genomic instability, a hallmark of cancer. In the present review we discuss the mechanistic basis of replication licensing deregulation, which leads to systemic effects, exemplified by its role in carcinogenesis and a variety of genetic syndromes. In addition, new insights demonstrate that above a particular threshold, the replication licensing factor Cdc6 acts as global transcriptional regulator, outlining new lines of exploration. The role of the putative replication licensing factor ChlR1/DDX11, mutated in the Warsaw Breakage Syndrome, in cancer is also considered. Finally, future perspectives focused on the potential therapeutic advantage by targeting replication licensing factors, and particularly Cdc6, are discussed.", "title": "Exploring and exploiting the systemic effects of deregulated replication licensing." }, { "docid": "6121668", "text": "OBJECTIVES To investigate the expressions of survivin and Cyclooxygenase-2 (COX-2), and their possible correlations in the development of endometrial adenocarcinoma (EC). We also looked at their association with classical prognostic factors in EC. To our knowledge, this is the first time survivin expression is investigated in terms of its relation to COX-2 in the developmental pathway of EC. \n METHODS Archived tissue samples of 50 EC, 30 endometrial hyperplasia and 20 proliferative endometrium were selected and immunohistochemically analyzed for survivin and COX-2 expression. \n RESULTS Both survivin and COX-2 were overexpressed in hyperplasia and endometrial adenocarcinoma cases compared to proliferative endometrium, which was statistically significant (p=0.01, p=0.02, respectively). Among EC cases, survivin and COX-2 were strongly positive in 38 (76%) and 30 (60%) patients, respectively. Furthermore, we found survivin and COX-2 to be positively correlated, which was also statistically significant (p=0.0001, r=0.46). Neither survivin nor COX-2 expression was correlated with classical prognostic factors of endometrial carcinoma such as myometrial invasion, grade or lymph node metastasis (p>0.05). Neither COX-2 nor survivin had an impact on overall survival (p>0.05). \n CONCLUSIONS Both survivin and COX-2 are overexpressed, and they seem to be early events in the occurrence of EC. Moreover, protein products of these two genes are positively correlated. COX-2 and survivin might share a common molecular pathway or enhance each other's actions in the developmental pathway of EC. Molecular basis of such a relationship should be further investigated in endometrial carcinogenesis.", "title": "COX-2 and survivin are overexpressed and positively correlated in endometrial carcinoma." }, { "docid": "9634465", "text": "Direct reprogramming is a promising approach in regenerative medicine. Overexpression of the cardiac transcription factors Gata4, Mef2c, and Tbx5 (GMT) or GMT plus Hand2 (GHMT) directly reprogram fibroblasts into cardiomyocyte-like cells (iCMs). However, the critical timing of transgene expression and the molecular mechanisms for cardiac reprogramming remain unclear. The conventional doxycycline (Dox)-inducible temporal transgene expression systems require simultaneous transduction of two vectors (pLVX-rtTA/pLVX-cDNA) harboring the reverse tetracycline transactivator (rtTA) and the tetracycline response element (TRE)-controlled transgene, respectively, leading to inefficient cardiac reprogramming. Herein, we developed a single-construct-based polycistronic Dox-inducible vector (pDox-cDNA) expressing both the rtTA and TRE-controlled transgenes. Fluorescence activated cell sorting (FACS) analyses, quantitative RT-PCR, and immunostaining revealed that pDox-GMT increased cardiac reprogramming three-fold compared to the conventional pLVX-rtTA/pLVX-GMT. After four weeks, pDox-GMT-induced iCMs expressed multiple cardiac genes, produced sarcomeric structures, and beat spontaneously. Co-transduction of pDox-Hand2 with retroviral pMX-GMT increased cardiac reprogramming three-fold compared to pMX-GMT alone. Temporal Dox administration revealed that Hand2 transgene expression is critical during the first two weeks of cardiac reprogramming. Microarray analyses demonstrated that Hand2 represses cell cycle-promoting genes and enhances cardiac reprogramming. Thus, we have developed an efficient temporal transgene expression system, which could be invaluable in the study of cardiac reprogramming.", "title": "Single-Construct Polycistronic Doxycycline-Inducible Vectors Improve Direct Cardiac Reprogramming and Can Be Used to Identify the Critical Timing of Transgene Expression" }, { "docid": "8133180", "text": "Germline mutations in the RET tyrosine kinase gene are responsible for the development of multiple endocrine neoplasia 2A and 2B (MEN2A and MEN2B). However, knowledge of the fundamental principles that determine the mutant RET-mediated signaling remains elusive. Here, we report increased expression of mitogen-activated protein kinase phosphatase-2 (MKP-2) in carcinomas developed in transgenic mice carrying RET with the MEN2A mutation (RET-MEN2A). The expression of MKP-2 was not only induced by RET-MEN2A or RET-MEN2B mutant proteins but also by the activation of endogenous RET by its ligand, glial cell line-derived neurotrophic factor (GDNF). MKP-2 expression was also evident in the MKK-f cell line, which was established from a mammary tumor developed in a RET-MEN2A transgenic mouse. Inhibition of MKP-2 attenuated the in vitro and in vivo proliferation of MKK-f cells, which was mediated by the suppression of cyclin B1 expression. Furthermore, we found that MKP-2 is highly expressed in medullary thyroid carcinomas derived from MEN2A patients. These findings suggest that the increased expression of MKP-2 may play a crucial role in oncogenic signaling downstream of mutant RET, leading to deregulation of cell cycle.", "title": "Roles of induced expression of MAPK phosphatase-2 in tumor development in RET-MEN2A transgenic mice" }, { "docid": "42279414", "text": "For more than 60 years, the chemical induction of tumors in mouse skin has been used to study mechanisms of epithelial carcinogenesis and evaluate modifying factors. In the traditional two-stage skin carcinogenesis model, the initiation phase is accomplished by the application of a sub-carcinogenic dose of a carcinogen. Subsequently, tumor development is elicited by repeated treatment with a tumor-promoting agent. The initiation protocol can be completed within 1–3 h depending on the number of mice used; whereas the promotion phase requires twice weekly treatments (1–2 h) and once weekly tumor palpation (1–2 h) for the duration of the study. Using the protocol described here, a highly reproducible papilloma burden is expected within 10–20 weeks with progression of a portion of the tumors to squamous cell carcinomas within 20–50 weeks. In contrast to complete skin carcinogenesis, the two-stage model allows for greater yield of premalignant lesions, as well as separation of the initiation and promotion phases.", "title": "Multi-stage chemical carcinogenesis in mouse skin: Fundamentals and applications" }, { "docid": "10024681", "text": "Deregulation of microRNA (miRNA) expression can have a critical role in carcinogenesis. Here we show in prostate cancer that miRNA-205 (miR-205) transcription is commonly repressed and the MIR-205 locus is hypermethylated. LOC642587, the MIR-205 host gene of unknown function, is also concordantly inactivated. We show that miR-205 targets mediator 1 (MED1, also called TRAP220 and PPARBP) for transcriptional silencing in normal prostate cells, leading to reduction in MED1 mRNA levels, and in total and active phospho-MED1 protein. Overexpression of miR-205 in prostate cancer cells negatively affects cell viability, consistent with a tumor suppressor function. We found that hypermethylation of the MIR-205 locus was strongly related with a decrease in miR-205 expression and an increase in MED1 expression in primary tumor samples (n=14), when compared with matched normal prostate (n=7). An expanded patient cohort (tumor n=149, matched normal n=30) also showed significant MIR-205 DNA methylation in tumors compared with normal, and MIR-205 hypermethylation is significantly associated with biochemical recurrence (hazard ratio=2.005, 95% confidence interval (1.109, 3.625), P=0.02), in patients with low preoperative prostate specific antigen. In summary, these results suggest that miR-205 is an epigenetically regulated tumor suppressor that targets MED1 and may provide a potential biomarker in prostate cancer management.", "title": "Epigenetic-induced repression of microRNA-205 is associated with MED1 activation and a poorer prognosis in localized prostate cancer" }, { "docid": "23122306", "text": "In an experiment to clarify the involvement of oxygen radicals in lung carcinogenesis induced by diesel exhaust particles (DEP), we found that there is a strong relation between lung tumor response and formation of 8-hydroxydeoxyguanosine (8-OHdG) in lung DNA of mice administered DEP by repeated intratracheal instillation. Repeated intratracheal instillation of DEP also induced the activity of cytochrome P-450 reductase in the lungs as a representative enzyme of superoxide generation, and two types of nitric oxide (NO) synthase, cNOS and iNOS, in the lungs. On the other hand, activities of CuZn-superoxide dismutase (SOD) and Mn-SOD antioxidant enzymes were depressed by the instillation of DEP. These results suggest that generation of superoxide, hydroxyI radical, and nitric oxide are increased in epithelial cells in airways, and that the increased superoxide and nitric oxide react very easily to produce peroxynitrite (ONOO(-)). The peroxynitrite also produce hydroxyI radical. The hydroxyl radical may play an important role in carcinogenesis by DEP.", "title": "Lung Carcinogenesis by Diesel Exhaust Particles and the Carcinogenic Mechanism Via Active Oxygens." }, { "docid": "25263942", "text": "Endometrial polyps are very common benign endometrial lesions, but their pathogenesis is poorly understood, except for a few studies indicating the possibility of benign stromal neoplasm. Although the histopathological diagnosis of endometrial polyp on a surgical specimen is straightforward, it is often difficult to differentiate endometrial polyp from endometrial hyperplasia on a biopsy or curettage specimen. Presently, there is no immunohistochemical marker helpful in this differential diagnosis. In this study, we examined p16 expression in 35 endometrial polyps and 33 cases of endometrial hyperplasia that included 16 simple hyperplasias, 14 complex atypical hyperplasias, and 3 complex hyperplasias without atypia. Stromal p16 expression differed significantly between the two groups; it was seen in 31 (89 %) endometrial polyps, but in only 1 (3 %) endometrial hyperplasia. The percentage of p16-positive stromal cells ranged from 10 to 90 % (mean, 47 %) and the positive cells tended to be distributed around glands. Six cases of endometrial hyperplasia within an endometrial polyp were also examined and all cases showed stromal p16 expression. There was no difference in glandular p16 expression between endometrial polyps 33 (94 %) and hyperplasia 27 (82 %). The p16-immunoreactivity was mostly confined to metaplastic epithelial cells in both groups. Stromal p16 expression might be a peculiar characteristic of endometrial polyp and constitute a useful marker for the diagnosis, especially in fragmented specimens from biopsy or curettage. Stromal p16 expression might be a reflection of p16-induced cellular senescence, which has been documented in several benign mesenchymal neoplasms.", "title": "Stromal p16 expression differentiates endometrial polyp from endometrial hyperplasia" }, { "docid": "5271210", "text": "MicroRNAs (miRNAs) are evolutionarily conserved small noncoding RNAs involved in the regulation of gene expression and protein translation. Many studies have shown that they play a crucial role in driving organ and tissue differentiation during embryogenesis and in the fine-tuning of fundamental biological processes, such as proliferation and apoptosis. Growing evidence indicates that their deregulation plays an important role in cancer onset and progression as well, where they act as oncogenes or oncosuppressors. In this review, we highlight the most recent findings regarding the role of miRNAs in hepatocellular carcinoma (HCC) by analyzing the possible mechanisms by which they contribute to this neoplasm. Moreover, we discuss the possible role of circulating miRNAs as biomarkers, a field that needs urgent improvement in the clinical surveillance of HCC, and the fascinating possibility of using them as therapeutic targets or drugs themselves.", "title": "MicroRNAs: new tools for diagnosis, prognosis, and therapy in hepatocellular carcinoma?" }, { "docid": "15928989", "text": "Successful pregnancy requires coordination of an array of signals and factors from multiple tissues. One such element, liver receptor homolog-1 (Lrh-1), is an orphan nuclear receptor that regulates metabolism and hormone synthesis. It is strongly expressed in granulosa cells of ovarian follicles and in the corpus luteum of rodents and humans. Germline ablation of Nr5a2 (also called Lrh-1), the gene coding for Lrh-1, in mice is embryonically lethal at gastrulation. Depletion of Lrh-1 in the ovarian follicle shows that it regulates genes required for both steroid synthesis and ovulation. To study the effects of Lrh-1 on mouse gestation, we genetically disrupted its expression in the corpus luteum, resulting in luteal insufficiency. Hormone replacement permitted embryo implantation but was followed by gestational failure with impaired endometrial decidualization, compromised placental formation, fetal growth retardation and fetal death. Lrh-1 is also expressed in the mouse and human endometrium, and in a primary culture of human endometrial stromal cells, reduction of NR5A2 transcript abundance by RNA interference abrogated decidualization. These findings show that Lrh-1 is necessary for maintenance of the corpus luteum, for promotion of decidualization and for formation of the placenta. It therefore has multiple, indispensible roles in establishing and sustaining pregnancy.", "title": "Liver receptor homolog-1 is essential for pregnancy" }, { "docid": "16346504", "text": "BACKGROUND Growth arrest-specific 5 (GAS5) was reported to be implicated and aberrantly express in multiple cancers. However, the expression and mechanism of action of GAS5 were largely poor understood in endometrial carcinoma. \n RESULTS According to the result of real-time reverse-transcriptase polymerase chain reaction (RT-PCR) and flow cytometry analysis, we identified that GAS5 was down-regulated in endometrial cancer cells and stimulated the apoptosis of endometrial cancer cells. To investigate the expression of GAS5, PTEN and miR-103, RT-PCR was performed. And we found that the expression of PTEN was up-regulated when endometrial cancer cells overexpressed GAS5. The prediction of bioinformatics online revealed that GAS5 could bind to miR-103, which was further found to be regulated by GAS5. Finally, we found that miR-103 mimic could decrease the mRNA and protein levels of PTEN through luciferase reporter assay and western blotting, and GAS5 plasmid may reverse this regulation effect in endometrial cancer cells. \n CONCLUSION In summary, we demonstrate that GAS5 acts as an tumor suppressor lncRNA in endometrial cancer. Through inhibiting the expression of miR-103, GAS5 significantly enhanced the expression of PTEN to promote cancer cell apoptosis, and, thus, could be an important mediator in the pathogenesis of endometrial cancer.", "title": "LncRNA-GAS5 induces PTEN expression through inhibiting miR-103 in endometrial cancer cells" }, { "docid": "23577867", "text": "Conditions related to chronic hyperinsulinemia, such as obesity, noninsulin dependent diabetes mellitus and polycystic ovary syndrome, are associated with an increased risk of endometrial cancer. Elevated plasma IGF-I and decreased levels of IGF-binding proteins have been shown to be associated with increased risk of several cancer types that are frequent in affluent societies. We investigated for the first time in a prospective study the association of pre-diagnostic blood concentrations of C-peptide (a marker of pancreatic insulin production), IGF-I, IGFBP-1, -2 and -3 with endometrial cancer risk. A case-control study was nested within 3 cohorts in New York (USA), Umeå (Sweden) and Milan (Italy). It included 166 women with primary invasive endometrial cancer and 315 matched controls, of which 44 case and 78 control subjects were premenopausal at recruitment. Endometrial cancer risk increased with increasing levels of C-peptide (ptrend = 0.0002), up to an odds ratio (OR) of 4.76 [95% confidence interval (CI) = 1.91-11.8] for the highest quintile. This association remained after adjustment for BMI and other confounders [OR for the top quintile = 4.40 (1.65-11.7)]. IGFBP-1 levels were inversely related to endometrial cancer [ptrend = 0.002; OR in the upper quintile = 0.30 (0.15-0.62)], but the association was weakened and lost statistical significance after adjustment for confounders [ptrend = 0.06; OR in the upper quintile = 0.49 (0.22-1.07)]. Risk was unrelated to levels of IGF-I, IGFBP-2 and IGFBP-3. Chronic hyperinsulinemia, as reflected by increased circulating C-peptide, is associated with increased endometrial cancer risk. Decrease in the prevalence of chronic hyperinsulinemia, through changes in lifestyle or medication, is expected to prevent endometrial cancer.", "title": "Prediagnostic levels of C-peptide, IGF-I, IGFBP -1, -2 and -3 and risk of endometrial cancer." }, { "docid": "9239963", "text": "Excessive exposure to estradiol represents the main risk factor for endometrial cancer. The abnormally high estradiol levels in the endometrium of women with endometrial cancer are most likely due to overproduction by the tumour itself. Endometrial cancer cells express the genes encoding the steroidogenic enzymes involved in estradiol synthesis. Here we used RT-PCR and Western blot to show that the nuclear receptors SF1 and LRH1, two well-known regulators of steroidogenic gene expression in gonadal and adrenal cells, are also expressed in endometrial cancer cell lines. By transient transfections, we found that SF1 and LRH1, but not the related nuclear receptor NUR77, can activate the promoters of three human steroidogenic genes: STAR, HSD3B2, and CYP19A1 PII. Similarly, forskolin but not PMA, could activate all three promoters. In addition, we found that both SF1 and LRH1 can transcriptionally cooperate with the AP-1 family members c-JUN and c-FOS, known to be associated with enhanced proliferation of endometrial carcinoma cells, to further enhance activation of the STAR, HSD3B2, and CYP19A1 PII promoters. All together, our data provide novel insights into the mechanisms of steroidogenic gene expression in endometrial cancer cells and thus in the regulation of estradiol biosynthesis by tumour cells.", "title": "The nuclear receptors SF1 and LRH1 are expressed in endometrial cancer cells and regulate steroidogenic gene transcription by cooperating with AP-1 factors." }, { "docid": "8774475", "text": "Loss of cell polarity proteins such as Scribble induces neoplasia in Drosophila by promoting uncontrolled proliferation. In mammals, the role that polarity proteins play during tumorigenesis is not well understood. Here, we demonstrate that depletion of Scribble in mammary epithelia disrupts cell polarity, blocks three-dimensional morphogenesis, inhibits apoptosis, and induces dysplasia in vivo that progress to tumors after long latency. Loss of Scribble cooperates with oncogenes such as c-myc to transform epithelial cells and induce tumors in vivo by blocking activation of an apoptosis pathway. Like depletion, mislocalization of Scribble from cell-cell junction was sufficient to promote cell transformation. Interestingly, spontaneous mammary tumors in mice and humans possess both downregulated and mislocalized Scribble. Thus, we demonstrate that scribble inhibits breast cancer formation and that deregulation of polarity pathways promotes dysplastic and neoplastic growth in mammals by disrupting morphogenesis and inhibiting cell death.", "title": "Deregulation of Scribble Promotes Mammary Tumorigenesis and Reveals a Role for Cell Polarity in Carcinoma" }, { "docid": "11359243", "text": "Altered DNA methylation occurs ubiquitously in human cancer from the earliest measurable stages. A cogent approach to understanding the mechanism and timing of altered DNA methylation is to analyze it in the context of carcinogenesis by a defined agent. Epstein-Barr virus (EBV) is a human oncogenic herpesvirus associated with lymphoma and nasopharyngeal carcinoma, but also used commonly in the laboratory to immortalize human B-cells in culture. Here we have performed whole-genome bisulfite sequencing of normal B-cells, activated B-cells, and EBV-immortalized B-cells from the same three individuals, in order to identify the impact of transformation on the methylome. Surprisingly, large-scale hypomethylated blocks comprising two-thirds of the genome were induced by EBV immortalization but not by B-cell activation per se. These regions largely corresponded to hypomethylated blocks that we have observed in human cancer, and they were associated with gene-expression hypervariability, similar to human cancer, and consistent with a model of epigenomic change promoting tumor cell heterogeneity. We also describe small-scale changes in DNA methylation near CpG islands. These results suggest that methylation disruption is an early and critical step in malignant transformation.", "title": "Large-scale hypomethylated blocks associated with Epstein-Barr virus-induced B-cell immortalization." }, { "docid": "2389574", "text": "PURPOSE Overexpression of the oncogen Stathmin has been linked to aggressive endometrial carcinoma and a potential for PI3Kinase inhibitors in this disease. We wanted to validate the prognostic value of Stathmin expression in a large prospective multicenter setting. As lymph node sampling is part of current surgical staging, we also aimed to test if Stathmin expression in endometrial curettage specimens could predict lymph node metastasis. EXPERIMENTAL DESIGN A total of 1,076 endometrial cancer patients have been recruited from 10 centers to investigate the biological tumor marker Stathmin in relation to clinicopathologic variables, including lymph node status and survival. Stathmin immunohistochemical staining was carried out in 477 hysterectomy and 818 curettage specimens. \n RESULTS Seventy-one percent of the patients (n = 763) were subjected to lymph node sampling, of which 12% had metastatic nodes (n = 94). Overexpression of Stathmin was detected in 37% (302 of 818) of the curettage and in 18% (84 of 477) of the hysterectomy specimens investigated. Stathmin overexpression in curettage and hysterectomy specimens were highly correlated and significantly associated with nonendometrioid histology, high grade, and aneuploidy. Stathmin analysis in preoperative curettage samples significantly correlated with, and was an independent predictor of, lymph node metastases. High Stathmin expression was associated with poor disease-specific survival (P ≤ 0.002) both in curettage and hysterectomy specimens. \n CONCLUSIONS Stathmin immunohistochemical staining identifies endometrial carcinomas with lymph node metastases and poor survival. The value, as a predictive marker for response to PI3Kinase inhibition and as a tool to stratify patients for lymph node sampling in endometrial carcinomas, remains to be determined.", "title": "Stathmin overexpression identifies high-risk patients and lymph node metastasis in endometrial cancer." }, { "docid": "45015767", "text": "BACKGROUND Adenocarcinoma of the endometrium is the most common gynecologic malignancy in the United States, accounting for approximately 36,000 diagnoses of invasive carcinoma annually. The most common histologic type, endometrioid adenocarcinoma (EC), accounts for 75-80% of patients. The objective of this work was to estimate the prevalence of concurrent carcinoma in women with a biopsy diagnosis of the precursor lesion, atypical endometrial hyperplasia (AEH). \n METHODS This prospective cohort study included women who had a community diagnosis of AEH. Diagnostic biopsy specimens were reviewed independently by three gynecologic pathologists who used International Society of Gynecologic Pathologists/World Health Organization criteria. Study participants underwent hysterectomy within 12 weeks of entry onto protocol without interval treatment. The hysterectomy slides also were reviewed by the study pathologists, and their findings were used in the subsequent analyses. \n RESULTS Between November 1998 and June 2003, 306 women were enrolled on the study. Of these, 17 women were not included in the analysis: Two patients had unreadable slides because of poor processing or insufficient tissue, 2 patients had only slides that were not endometrial, the slides for 5 patients were not available for review, and 8 of the hysterectomy specimens were excluded because they showed evidence of interval intervention, either progestin effect or ablation. In total, 289 patients were included in the current analysis. The study panel review of the AEH biopsy specimens was interpreted as follows: 74 of 289 specimens (25.6%) were diagnosed as less than AEH, 115 of 289 specimens (39.8%) were diagnosed as AEH, and 84 of 289 specimens (29.1%) were diagnosed as endometrial carcinoma. In 5.5% (16 of 289 specimens), there was no consensus on the biopsy diagnosis. The rate of concurrent endometrial carcinoma for analyzed specimens was 42.6% (123 of 289 specimens). Of these, 30.9% (38 of 123 specimens) were myoinvasive, and 10.6% (13 of 123 specimens) involved the outer 50% of the myometrium. Among the women who had hysterectomy specimens with carcinoma, 14 of 74 women (18.9%) had a study panel biopsy consensus diagnosis of less than AEH, 45 of 115 women (39.1%) had a study panel biopsy consensus diagnosis of AEH, and 54 of 84 women (64.3%) had a study panel diagnosis of carcinoma. Among women who had no consensus in their biopsy diagnosis, 10 of 16 women (62.5%) had carcinoma in their hysterectomy specimens. \n CONCLUSIONS The prevalence of endometrial carcinoma in patients who had a community hospital biopsy diagnosis of AEH was high (42.6%). When considering management strategies for women who have a biopsy diagnosis of AEH, clinicians and patients should take into account the considerable rate of concurrent carcinoma.", "title": "Concurrent endometrial carcinoma in women with a biopsy diagnosis of atypical endometrial hyperplasia: a Gynecologic Oncology Group study." }, { "docid": "43014661", "text": "Xeroderma pigmentosum variant (XPV) patients with mutations in the DNA polymerase eta (pol eta) gene are hypersensitive to sunlight and have greatly increased susceptibility to sunlight-induced skin cancer. Consistent with the ability of Pol eta to efficiently bypass UV light-induced cyclobutane pyrimidine dimers, XPV cells lacking Pol eta have diminished capacity to replicate UV-damaged DNA and are sensitive to UV light-induced killing and mutagenesis. To better understand these and other Pol eta functions, we generated Pol eta-deficient mice. Mice homozygous for a null mutation in pol eta are viable, fertile, and do not show any obvious spontaneous defects during the first year of life. However, fibroblasts derived from these mutant mice are sensitive to killing by exposure to UV light, and all Pol eta-deficient mice develop skin tumors after UV irradiation, in contrast to the wild-type littermate controls that did not develop such tumors. These results and biochemical studies of translesion synthesis by mouse Pol eta indicate that Pol eta-dependent bypass of cyclobutane pyrimidine dimers suppresses UV light-induced skin cancer in mice. Moreover, 37.5% of pol eta heterozygous mice also developed skin cancer during 5 months after a 5-month exposure to UV light, suggesting that humans who are heterozygous for mutations in pol eta may also have an increased risk of skin cancer.", "title": "Increased susceptibility to UV-induced skin carcinogenesis in polymerase eta-deficient mice." }, { "docid": "3210545", "text": "BACKGROUND Three quarter of endometrial carcinomas are treated at early stage. Still, 15 to 20% of these patients experience recurrence, with little effect from systemic therapies. Homo sapiens v-Ki-ras2 Kirsten rat sarcoma viral oncogenes homologue (KRAS) mutations have been reported to have an important role in tumorigenesis for human cancers, but there is limited knowledge regarding clinical relevance of KRAS status in endometrial carcinomas. \n METHODS We have performed a comprehensive and integrated characterisation of genome-wide expression related to KRAS mutations and copy-number alterations in primary- and metastatic endometrial carcinoma lesions in relation to clinical and histopathological data. A primary investigation set and clinical validation set was applied, consisting of 414 primary tumours and 61 metastatic lesions totally. \n RESULTS Amplification and gain of KRAS present in 3% of the primary lesions and 18% of metastatic lesions correlated significantly with poor outcome, high International Federation of Gynaecology and Obstetrics stage, non-endometrioid subtype, high grade, aneuploidy, receptor loss and high KRAS mRNA levels, also found to be associated with aggressive phenotype. In contrast, KRAS mutations were present in 14.7% of primary lesions with no increase in metastatic lesions, and did not influence outcome, but was significantly associated with endometrioid subtype, low grade and obesity. \n CONCLUSION These results support that KRAS amplification and KRAS mRNA expression, both increasing from primary to metastatic lesions, are relevant for endometrial carcinoma disease progression.", "title": "KRAS gene amplification and overexpression but not mutation associates with aggressive and metastatic endometrial cancer" } ]

[ { "docid": "2097256", "text": "BACKGROUND Aedes aegypti, the major vector of dengue viruses, often breeds in water storage containers used by households without tap water supply, and occurs in high numbers even in dense urban areas. We analysed the interaction between human population density and lack of tap water as a cause of dengue fever outbreaks with the aim of identifying geographic areas at highest risk. \n METHODS AND FINDINGS We conducted an individual-level cohort study in a population of 75,000 geo-referenced households in Vietnam over the course of two epidemics, on the basis of dengue hospital admissions (n = 3,013). We applied space-time scan statistics and mathematical models to confirm the findings. We identified a surprisingly narrow range of critical human population densities between around 3,000 to 7,000 people/km² prone to dengue outbreaks. In the study area, this population density was typical of villages and some peri-urban areas. Scan statistics showed that areas with a high population density or adequate water supply did not experience severe outbreaks. The risk of dengue was higher in rural than in urban areas, largely explained by lack of piped water supply, and in human population densities more often falling within the critical range. Mathematical modeling suggests that simple assumptions regarding area-level vector/host ratios may explain the occurrence of outbreaks. \n CONCLUSIONS Rural areas may contribute at least as much to the dissemination of dengue fever as cities. Improving water supply and vector control in areas with a human population density critical for dengue transmission could increase the efficiency of control efforts. Please see later in the article for the Editors' Summary.", "title": "Population Density, Water Supply, and the Risk of Dengue Fever in Vietnam: Cohort Study and Spatial Analysis" } ]

[ { "docid": "18816720", "text": "BACKGROUND Transmission of dengue viruses (DENV), the leading cause of arboviral disease worldwide, is known to vary through time and space, likely owing to a combination of factors related to the human host, virus, mosquito vector, and environment. An improved understanding of variation in transmission patterns is fundamental to conducting surveillance and implementing disease prevention strategies. To test the hypothesis that DENV transmission is spatially and temporally focal, we compared geographic and temporal characteristics within Thai villages where DENV are and are not being actively transmitted. \n METHODS AND FINDINGS Cluster investigations were conducted within 100 m of homes where febrile index children with (positive clusters) and without (negative clusters) acute dengue lived during two seasons of peak DENV transmission. Data on human infection and mosquito infection/density were examined to precisely (1) define the spatial and temporal dimensions of DENV transmission, (2) correlate these factors with variation in DENV transmission, and (3) determine the burden of inapparent and symptomatic infections. Among 556 village children enrolled as neighbors of 12 dengue-positive and 22 dengue-negative index cases, all 27 DENV infections (4.9% of enrollees) occurred in positive clusters (p < 0.01; attributable risk [AR] = 10.4 per 100; 95% confidence interval 1-19.8 per 100]. In positive clusters, 12.4% of enrollees became infected in a 15-d period and DENV infections were aggregated centrally near homes of index cases. As only 1 of 217 pairs of serologic specimens tested in positive clusters revealed a recent DENV infection that occurred prior to cluster initiation, we attribute the observed DENV transmission subsequent to cluster investigation to recent DENV transmission activity. Of the 1,022 female adult Ae. aegypti collected, all eight (0.8%) dengue-infected mosquitoes came from houses in positive clusters; none from control clusters or schools. Distinguishing features between positive and negative clusters were greater availability of piped water in negative clusters (p < 0.01) and greater number of Ae. aegypti pupae per person in positive clusters (p = 0.04). During primarily DENV-4 transmission seasons, the ratio of inapparent to symptomatic infections was nearly 1:1 among child enrollees. Study limitations included inability to sample all children and mosquitoes within each cluster and our reliance on serologic rather than virologic evidence of interval infections in enrollees given restrictions on the frequency of blood collections in children. \n CONCLUSIONS Our data reveal the remarkably focal nature of DENV transmission within a hyperendemic rural area of Thailand. These data suggest that active school-based dengue case detection prompting local spraying could contain recent virus introductions and reduce the longitudinal risk of virus spread within rural areas. Our results should prompt future cluster studies to explore how host immune and behavioral aspects may impact DENV transmission and prevention strategies. Cluster methodology could serve as a useful research tool for investigation of other temporally and spatially clustered infectious diseases.", "title": "Spatial and Temporal Clustering of Dengue Virus Transmission in Thai Villages" }, { "docid": "8665891", "text": "Dengue virus and its four serotypes (DENV 1-4) infect approximately 390 million people worldwide each year, with most cases in tropical and subtropical regions. Because of repeated introduction of DENV from epidemic regions and suitable weather conditions, many regions have shifted from hypo-endemicity to hyper-endemicity over recent decades. Since the first dengue outbreak in 1978, it is crucial to understand the current situation in China over nearly 40 years. The purpose of the study was to examine whether dengue in China was endemic or not, which is essential for relevant dengue control and prevention strategy implementation in China. The study, combining epidemiological characteristics of dengue from the disease notification system, phylogenetic and phylogeographic analyses, showed that all four serotypes had been detected in Guangzhou, China, which was dominated by DENV 1-2. The Maximum Likelihood tree analytic results showed that the virus detected in Guangzhou localized in different clades, except of virus of 2002 and 2003 clustered together. There existed the mutual introductions between Guangzhou and Southeast Asia. Most of the viruses were imported from Southeast Asia and the sources of outbreaks in Guangzhou mainly originated from Thailand, Indonesia, and the Philippines. The study indicates that dengue in China still remains as an imported disease, with the possibility of localization.", "title": "Dengue is still an imported disease in China: a case study in Guangzhou." }, { "docid": "21003930", "text": "BACKGROUND Long-term exposure to pollution can lead to an increase in the rate of decline of lung function, especially in older individuals and in those with chronic obstructive pulmonary disease (COPD), whereas shorter-term exposure at higher pollution levels has been implicated in causing excess deaths from ischaemic heart disease and exacerbations of COPD. We aimed to assess the effects on respiratory and cardiovascular responses of walking down a busy street with high levels of pollution compared with walking in a traffic-free area with lower pollution levels in older adults. \n METHODS In this randomised, crossover study, we recruited men and women aged 60 years and older with angiographically proven stable ischaemic heart disease or stage 2 Global initiative for Obstructive Lung Disease (GOLD) COPD who had been clinically stable for 6 months, and age-matched healthy volunteers. Individuals with ischaemic heart disease or COPD were recruited from existing databases or outpatient respiratory and cardiology clinics at the Royal Brompton & Harefield NHS Foundation Trust and age-matched healthy volunteers using advertising and existing databases. All participants had abstained from smoking for at least 12 months and medications were taken as recommended by participants' doctors during the study. Participants were randomly assigned by drawing numbered disks at random from a bag to do a 2 h walk either along a commercial street in London (Oxford Street) or in an urban park (Hyde Park). Baseline measurements of participants were taken before the walk in the hospital laboratory. During each walk session, black carbon, particulate matter (PM) concentrations, ultrafine particles, and nitrogen dioxide (NO2) concentrations were measured. \n FINDINGS Between October, 2012, and June, 2014, we screened 135 participants, of whom 40 healthy volunteers, 40 individuals with COPD, and 39 with ischaemic heart disease were recruited. Concentrations of black carbon, NO2, PM10, PM2.5, and ultrafine particles were higher on Oxford Street than in Hyde Park. Participants with COPD reported more cough (odds ratio [OR] 1·95, 95% CI 0·96-3·95; p<0·1), sputum (3·15, 1·39-7·13; p<0·05), shortness of breath (1·86, 0·97-3·57; p<0·1), and wheeze (4·00, 1·52-10·50; p<0·05) after walking down Oxford Street compared with Hyde Park. In all participants, irrespective of their disease status, walking in Hyde Park led to an increase in lung function (forced expiratory volume in the first second [FEV1] and forced vital capacity [FVC]) and a decrease in pulse wave velocity (PWV) and augmentation index up to 26 h after the walk. By contrast, these beneficial responses were attenuated after walking on Oxford Street. In participants with COPD, a reduction in FEV1 and FVC, and an increase in R5-20 were associated with an increase in during-walk exposure to NO2, ultrafine particles and PM2.5, and an increase in PWV and augmentation index with NO2 and ultrafine particles. In healthy volunteers, PWV and augmentation index were associated both with black carbon and ultrafine particles. \n INTERPRETATION Short-term exposure to traffic pollution prevents the beneficial cardiopulmonary effects of walking in people with COPD, ischaemic heart disease, and those free from chronic cardiopulmonary diseases. Medication use might reduce the adverse effects of air pollution in individuals with ischaemic heart disease. Policies should aim to control ambient levels of air pollution along busy streets in view of these negative health effects. \n FUNDING British Heart Foundation.", "title": "Respiratory and cardiovascular responses to walking down a traffic-polluted road compared with walking in a traffic-free area in participants aged 60 years and older with chronic lung or heart disease and age-matched healthy controls: a randomised, crossover study" }, { "docid": "42387637", "text": "RATIONALE Exposure to particulate air pollution has been related to increased hospitalization and death, particularly from cardiovascular disease. Lower blood DNA methylation content is found in processes related to cardiovascular outcomes, such as oxidative stress, aging, and atherosclerosis. \n OBJECTIVES We evaluated whether particulate pollution modifies DNA methylation in heavily methylated sequences with high representation throughout the human genome. \n METHODS We measured DNA methylation of long interspersed nucleotide element (LINE)-1 and Alu repetitive elements by quantitative polymerase chain reaction-pyrosequencing of 1,097 blood samples from 718 elderly participants in the Boston area Normative Aging Study. We used covariate-adjusted mixed models to account for within-subject correlation in repeated measures. We estimated the effects on DNA methylation of ambient particulate pollutants (black carbon, particulate matter with aerodynamic diameter < or = 2.5 microm [PM2.5], or sulfate) in multiple time windows (4 h to 7 d) before the examination. We estimated standardized regression coefficients (beta) expressing the fraction of a standard deviation change in DNA methylation associated with a standard deviation increase in exposure. \n MEASUREMENTS AND MAIN RESULTS Repetitive element DNA methylation varied in association with time-related variables, such as day of the week and season. LINE-1 methylation decreased after recent exposure to higher black carbon (beta = -0.11; 95% confidence interval [CI], -0.18 to -0.04; P = 0.002) and PM2.5 (beta = -0.13; 95% CI, -0.19 to -0.06; P < 0.001 for the 7-d moving average). In two-pollutant models, only black carbon, a tracer of traffic particles, was significantly associated with LINE-1 methylation (beta = -0.09; 95% CI, -0.17 to -0.01; P = 0.03). No association was found with Alu methylation (P > 0.12). \n CONCLUSIONS We found decreased repeated-element methylation after exposure to traffic particles. Whether decreased methylation mediates exposure-related health effects remains to be determined.", "title": "Rapid DNA methylation changes after exposure to traffic particles." }, { "docid": "17454301", "text": "A small, isolated outbreak of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) due to dengue virus type 2 (DEN-2) was documented in Santiago de Cuba on the island of Cuba beginning in January 1997. There were 205 DHF/DSS cases, all in persons older than age 15 years. All but three had evidence of a prior dengue infection, with the only known opportunity being the islandwide dengue virus type 1 (DEN-1) epidemic of 1977-1979. Virtually complete clinical and laboratory surveillance of overt disease was achieved. From December 1997 to January 1998, a random, age-stratified serum sample was obtained from 1,151 persons in 40 residential clusters in Santiago. Sera were tested for DEN-1 and DEN-2 neutralizing antibodies. The prevalence of DEN-2 antibodies in children age 15 years and under, born after the 1981 DEN-2 epidemic, was taken as the 1997 DEN-2 infection rate. This was adjusted slightly to accommodate observed cases, resulting in an estimated infection rate of 4.3%. Dengue fever and DHF/DSS attack rates were calculated from estimated total primary and secondary DEN-2 infections. Only 3% of 13,116 primary infections were overt. The DHF/DSS attack rate for adults of all ages was 420 per 10,000 secondary DEN-2 infections.", "title": "Epidemiologic studies on Dengue in Santiago de Cuba, 1997." }, { "docid": "11238951", "text": "Kaposi's sarcoma-associated herpesvirus (KSHV), also termed human herpesvirus type 8, is consistently identified in Kaposi's sarcoma, primary effusion lymphoma (PEL), and multicentric Castleman's disease. Here we report four cases of KSHV-bearing solid lymphomas that occurred in AIDS patients (cases 1 to 3) and in a human immunodeficiency virus (HIV)-seronegative person (case 4). The patients presented extranodal masses in the abdomen (cases 1, 3, and 4) or skin (case 2), and nodal involvement, together with Kaposi's sarcoma (case 3). The gastrointestinal tract was involved in two patients (cases 1 and 3). The patients did not develop a lymphomatous effusion. KSHV was detected in the tumor cells of all cases by immunohistochemistry and by polymerase chain reaction. Epstein-Barr virus was detected in two of the HIV-related cases. All KSHV-positive solid lymphomas exhibited PEL-like cell morphology. To investigate the relationship of these disorders to PEL and to other AIDS-associated diffuse large cell lymphomas, KSHV-positive solid lymphomas were tested for the expression of a set of genes that were previously shown by gene profiling analysis to define PEL tumor cells. The results showed that expression of this set of genes in KSHV-positive lymphomas is similar to that of PEL but distinct from KSHV-negative AIDS-associated diffuse large cell lymphomas. Because pathobiological features of KSHV-positive solid lymphomas closely mimic those of PEL, our results suggest that KSHV-positive solid lymphomas should be considered as a tissue-based variant of classical PEL, irrespective of HIV status.", "title": "Kaposi's sarcoma-associated herpesvirus/human herpesvirus type 8-positive solid lymphomas: a tissue-based variant of primary effusion lymphoma." }, { "docid": "9599194", "text": "With the recent availability of complete genomic sequences of many organisms, high-throughput and cost-efficient systems for gene cloning and functional analysis are in great demand. Although site-specific recombination-based cloning systems, such as Gateway cloning technology, are extremely useful for efficient transfer of DNA fragments into multiple destination vectors, the two-step cloning process is time consuming and expensive. Here, we report a zero background TA cloning system that provides simple and high-efficiency direct cloning of PCR-amplified DNA fragments with almost no self-ligation. The improved T-vector system takes advantage of the restriction enzyme XcmI to generate a T-overhang after digestion and the negative selection marker gene ccdB to eliminate the self-ligation background after transformation. We demonstrate the feasibility and flexibility of the technology by developing a set of transient and stable transformation vectors for constitutive gene expression, gene silencing, protein tagging, protein subcellular localization detection, and promoter fragment activity analysis in plants. Because the system can be easily adapted for developing specialized expression vectors for other organisms, zero background TA provides a general, cost-efficient, and high-throughput platform that complements the Gateway cloning system for gene cloning and functional genomics.", "title": "A versatile zero background T-vector system for gene cloning and functional genomics." }, { "docid": "25738896", "text": "The thymic transcription factor autoimmune regulator (Aire) prevents autoimmunity in part by promoting expression of tissue-specific self-antigens, which include many cancer antigens. For example, AIRE-deficient patients are predisposed to vitiligo, an autoimmune disease of melanocytes that is often triggered by efficacious immunotherapies against melanoma. Therefore, we hypothesized that Aire deficiency in mice may elevate immune responses to cancer and provide insights into how such responses might be triggered. In this study, we show that Aire deficiency decreases thymic expression of TRP-1 (TYRP1), which is a self-antigen in melanocytes and a cancer antigen in melanomas. Aire deficiency resulted in defective negative selection of TRP-1-specific T cells without affecting thymic numbers of regulatory T cells. Aire-deficient mice displayed elevated T-cell immune responses that were associated with suppression of melanoma outgrowth. Furthermore, transplantation of Aire-deficient thymic stroma was sufficient to confer more effective immune rejection of melanoma in an otherwise Aire wild-type host. Together, our work showed how Aire deficiency can enhance immune responses against melanoma and how manipulating TRP-1-specific T-cell negative selection may offer a logical strategy to enhance immune rejection of melanoma.", "title": "Aire deficiency promotes TRP-1-specific immune rejection of melanoma." }, { "docid": "35962023", "text": "Recent studies suggest a close relationship between cell metabolism and apoptosis. We have evaluated changes in lipid metabolism on permeabilized hepatocytes treated with truncated Bid (tBid) in the presence of caspase inhibitors and exogenous cytochrome c. The measurement of β-oxidation flux by labeled palmitate demonstrates that tBid inhibits β-oxidation, thereby resulting in the accumulation of palmitoyl-coenzyme A (CoA) and depletion of acetyl-carnitine and acylcarnitines, which is pathognomonic for inhibition of carnitine palmitoyltransferase-1 (CPT-1). We also show that tBid decreases CPT-1 activity by a mechanism independent of both malonyl-CoA, the key inhibitory molecule of CPT-1, and Bak and/or Bax, but dependent on cardiolipin decrease. Overexpression of Bcl-2, which is able to interact with CPT-1, counteracts the effects exerted by tBid on β-oxidation. The unexpected role of tBid in the regulation of lipid β-oxidation suggests a model in which tBid-induced metabolic decline leads to the accumulation of toxic lipid metabolites such as palmitoyl-CoA, which might become participants in the apoptotic pathway.", "title": "tBid induces alterations of mitochondrial fatty acid oxidation flux by malonyl-CoA-independent inhibition of carnitine palmitoyltransferase-1" }, { "docid": "4561402", "text": "Autoimmune polyendocrinopathy syndrome type 1 is a recessive Mendelian disorder resulting from mutations in a novel gene, AIRE, and is characterized by a spectrum of organ-specific autoimmune diseases. It is not known what tolerance mechanisms are defective as a result of AIRE mutation. By tracing the fate of autoreactive CD4+ T cells with high affinity for a pancreatic antigen in transgenic mice with an Aire mutation, we show here that Aire deficiency causes almost complete failure to delete the organ-specific cells in the thymus. These results indicate that autoimmune polyendocrinopathy syndrome 1 is caused by failure of a specialized mechanism for deleting forbidden T cell clones, establishing a central role for this tolerance mechanism.", "title": "Aire regulates negative selection of organ-specific T cells" }, { "docid": "3716075", "text": "BACKGROUND Dengue is the most common arbovirus infection globally, but its burden is poorly quantified. We estimated dengue mortality, incidence, and burden for the Global Burden of Disease Study 2013. \n METHODS We modelled mortality from vital registration, verbal autopsy, and surveillance data using the Cause of Death Ensemble Modelling tool. We modelled incidence from officially reported cases, and adjusted our raw estimates for under-reporting based on published estimates of expansion factors. In total, we had 1780 country-years of mortality data from 130 countries, 1636 country-years of dengue case reports from 76 countries, and expansion factor estimates for 14 countries. \n FINDINGS We estimated an average of 9221 dengue deaths per year between 1990 and 2013, increasing from a low of 8277 (95% uncertainty estimate 5353-10 649) in 1992, to a peak of 11 302 (6790-13 722) in 2010. This yielded a total of 576 900 (330 000-701 200) years of life lost to premature mortality attributable to dengue in 2013. The incidence of dengue increased greatly between 1990 and 2013, with the number of cases more than doubling every decade, from 8·3 million (3·3 million-17·2 million) apparent cases in 1990, to 58·4 million (23·6 million-121·9 million) apparent cases in 2013. When accounting for disability from moderate and severe acute dengue, and post-dengue chronic fatigue, 566 000 (186 000-1 415 000) years lived with disability were attributable to dengue in 2013. Considering fatal and non-fatal outcomes together, dengue was responsible for 1·14 million (0·73 million-1·98 million) disability-adjusted life-years in 2013. \n INTERPRETATION Although lower than other estimates, our results offer more evidence that the true symptomatic incidence of dengue probably falls within the commonly cited range of 50 million to 100 million cases per year. Our mortality estimates are lower than those presented elsewhere and should be considered in light of the totality of evidence suggesting that dengue mortality might, in fact, be substantially higher. \n FUNDING Bill & Melinda Gates Foundation.", "title": "The global burden of dengue: an analysis from the Global Burden of Disease Study 2013." }, { "docid": "23304931", "text": "PURPOSE Diffuse large B-cell lymphoma (DLBCL) represents a clinically heterogeneous disease. Models based on immunohistochemistry predict clinical outcome. These include subdivision into germinal center (GC) versus non-GC subtypes; proliferation index (measured by expression of Ki-67), and expression of BCL-2, FOXP1, or B-lymphocyte-induced maturation protein (Blimp-1)/PRDM1. We sought to determine whether immunohistochemical analyses of biopsies from patients with DLBCL having HIV infection are similarly relevant for prognosis. \n PATIENTS AND METHODS We examined 81 DLBCLs from patients with AIDS in AMC010 (cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP] v CHOP-rituximab) and AMC034 (etoposide, doxorubicin, vincristine, prednisone, and dose-adjusted cyclophosphamide plus rituximab concurrent v sequential) clinical trials and compared the immunophenotype with survival data, Epstein-Barr virus (EBV) positivity, and CD4 counts. \n RESULTS The GC and non-GC subtypes of DLBCL did not differ significantly with respect to overall survival or CD4 count at cancer presentation. EBV could be found in both subtypes of DLBCL, although less frequently in the GC subtype, and did not affect survival. Expression of FOXP1, Blimp-1/PRDM1, or BCL-2 was not correlated with the outcome in patients with AIDS-related DLBCL. \n CONCLUSION These data indicate that with current treatment strategies for lymphoma and control of HIV infection, commonly used immunohistochemical markers may not be clinically relevant in HIV-infected patients with DLBCL. The only predictive immunohistochemical marker was found to be Ki-67, where a higher proliferation index was associated with better survival, suggesting a better response to therapy in patients whose tumors had higher proliferation rates.", "title": "Immunophenotypic analysis of AIDS-related diffuse large B-cell lymphoma and clinical implications in patients from AIDS malignancies consortium clinical trials 010 and 034" }, { "docid": "301838", "text": "The thymic medulla provides a specialized microenvironment for the negative selection of T cells, with the presence of autoimmune regulator (Aire)-expressing medullary thymic epithelial cells (mTECs) during the embryonic-neonatal period being both necessary and sufficient to establish long-lasting tolerance. Here we showed that emergence of the first cohorts of Aire(+) mTECs at this key developmental stage, prior to αβ T cell repertoire selection, was jointly directed by Rankl(+) lymphoid tissue inducer cells and invariant Vγ5(+) dendritic epidermal T cell (DETC) progenitors that are the first thymocytes to express the products of gene rearrangement. In turn, generation of Aire(+) mTECs then fostered Skint-1-dependent, but Aire-independent, DETC progenitor maturation and the emergence of an invariant DETC repertoire. Hence, our data attributed a functional importance to the temporal development of Vγ5(+) γδ T cells during thymus medulla formation for αβ T cell tolerance induction and demonstrated a Rank-mediated reciprocal link between DETC and Aire(+) mTEC maturation.", "title": "Rank Signaling Links the Development of Invariant γδ T Cell Progenitors and Aire+ Medullary Epithelium" }, { "docid": "22414304", "text": "There is little information about treatment outcome in patients with smear-negative pulmonary tuberculosis (PTB) or extrapulmonary tuberculosis (EPTB) treated under routine programme conditions in subsaharan Africa. A prospective study was carried out to determine treatment outcome in an unselected cohort of TB patients admitted to Zomba General Hospital, Malawi. Eight hundred and twenty-seven adult TB patients (451 men and 376 women) were registered between 1 July and 31 December 1995. Standardized treatment outcomes of treatment completion, death, default, and transfer to another district were assessed in relation to type of TB, human immunodeficiency virus (HIV) serostatus, age and gender. Two hundred and fifty-four patients (31%) died by the end of treatment, half of the deaths occurring in the first month. Death rates were 19% among 386 patients with smear-positive PTB, 46% among 211 patients with smear-negative PTB, and 37% among 230 patients with EPTB; 77% of the patients were HIV seropositive. Among new patients, HIV-positive patients had higher death rates than HIV-negative patients (hazard ratio [HR] 2.5; 95% confidence interval [95% CI] 1.6-3.8). Smear-negative patients had the highest death rates (HR 3.9; 95% CI 2.7-5.5 compared to smear-positive patients), followed by EPTB patients (HR 2.6, 95% CI 1.8-3.7 compared to smear-positive patients). Death rates increased with age but were similar in men and women. Adult patients in Malawi with smear-negative PTB and EPTB have low treatment completion and high death rates, related to high levels of HIV infection. National TB control programmes in areas of high HIV prevalence should no longer ignore treatment outcomes in patients with smear-negative PTB or EPTB.", "title": "Treatment outcome of an unselected cohort of tuberculosis patients in relation to human immunodeficiency virus serostatus in Zomba Hospital, Malawi." }, { "docid": "8246090", "text": "Ion channels are classically understood to regulate the flux of ions across the plasma membrane in response to a variety of environmental and intracellular cues. Ion channels serve a number of functions in intracellular membranes as well. These channels may be temporarily localized to intracellular membranes as a function of their biosynthetic or secretory pathways, i.e., en route to their destination location. Intracellular membrane ion channels may also be located in the endocytic pathways, either being recycled back to the plasma membrane or targeted to the lysosome for degradation. Several channels do participate in intracellular signal transduction; the most well known example is the inositol 1,4,5-trisphosphate receptor (IP(3)R) in the endoplasmic reticulum. Some organellar intracellular membrane channels are required for the ionic homeostasis of their residing organelles. Several newly-discovered intracellular membrane Ca(2+) channels actually play active roles in membrane trafficking. Transient receptor potential (TRP) proteins are a superfamily (28 members in mammal) of Ca(2+)-permeable channels with diverse tissue distribution, subcellular localization, and physiological functions. Almost all mammalian TRP channels studied thus far, like their ancestor yeast TRP channel (TRPY1) that localizes to the vacuole compartment, are also (in addition to their plasma membrane localization) found to be localized to intracellular membranes. Accumulated evidence suggests that intracellularly-localized TRP channels actively participate in regulating membrane traffic, signal transduction, and vesicular ion homeostasis. This review aims to provide a summary of these recent works. The discussion will also be extended to the basic membrane and electrical properties of the TRP-residing compartments.", "title": "TRP channels of intracellular membranes." }, { "docid": "37643601", "text": "Many viruses go through a maturation step in the final stages of assembly before being transmitted to another host. The maturation process of flaviviruses is directed by the proteolytic cleavage of the precursor membrane protein (prM), turning inert virus into infectious particles. We have determined the 2.2 angstrom resolution crystal structure of a recombinant protein in which the dengue virus prM is linked to the envelope glycoprotein E. The structure represents the prM-E heterodimer and fits well into the cryo-electron microscopy density of immature virus at neutral pH. The pr peptide beta-barrel structure covers the fusion loop in E, preventing fusion with host cell membranes. The structure provides a basis for identifying the stages of its pH-directed conformational metamorphosis during maturation, ending with release of pr when budding from the host.", "title": "The flavivirus precursor membrane-envelope protein complex: structure and maturation." }, { "docid": "25134146", "text": "Hepatitis C virus (HCV) is frequently encountered in human immunodeficiency virus (HIV)-infected patients because of common routes of transmission. Previous studies suggested that HIV infection impaired the natural course of chronic hepatitis C, with a more rapid progression to cirrhosis. However, these studies did not assess the HIV infection impact on chronic hepatitis C by taking into account the risk factors for liver fibrosis progression: alcohol, sex, age at the contamination, and duration of HCV infection. We studied liver biopsy specimens of 2 groups of 58 patients that were infected by both HCV and HIV or by HCV alone. The 2 groups were matched according those risk factors, and liver biopsy responses were evaluated with the METAVIR items. The METAVIR activity was higher in HIV-positive than HIV-negative patients. Cirrhosis was more frequent: (1) in HIV-positive patients with CD4 < or = 200 cells/microL (45%) than in HIV-negative patients (10%) (P = .003), (2) in HIV-positive patients with CD4 < or = 200 cells/microL (45%) than in HIV-positive patients with CD4 > 200 cells/microL (17%) (P = .04). These differences, which were linked to HIV status, might be related to the enhanced HCV replication during HIV infection or other immune mechanisms that need further studies.", "title": "Impact of human immunodeficiency virus infection on the histological features of chronic hepatitis C: a case-control study. The MULTIVIRC group." }, { "docid": "39559521", "text": "The negative selection of self-reactive thymocytes depends on the expression of tissue-specific antigens by medullary thymic epithelial cells. The autoimmune regulator (Aire) protein plays an important role in turning on these antigens, and the absence of even one Aire-induced tissue-specific antigen in the thymus can lead to autoimmunity in the antigen-expressing target organ. Recently, Aire protein has been detected in peripheral lymphoid organs, suggesting that peripheral Aire plays a complementary role here. In these peripheral sites, Aire was found to regulate the expression of a group of tissue-specific antigens that is distinct from those expressed in the thymus. Furthermore, transgenic antigen expression in extrathymic Aire-expressing cells (eTACs) can mediate deletional tolerance, but the immunological relevance of Aire-dependent, endogenous tissue-specific antigens remains to be determined.", "title": "Control of central and peripheral tolerance by Aire." }, { "docid": "32827351", "text": "Aqueous solutions of lead salts (1, 2) and saturated solutions of lead hydroxide (1) have been used as stains to enhance the electron-scattering properties of components of biological materials examined in the electron microscope. Saturated solutions of lead hydroxide (1), while staining more intensely than either lead acetate or monobasic lead acetate (l , 2), form insoluble lead carbonate upon exposure to air. The avoidance of such precipitates which contaminate surfaces of sections during staining has been the stimulus for the development of elaborate procedures for exclusion of air or carbon dioxide (3, 4). Several modifications of Watson's lead hydroxide stain (1) have recently appeared (5-7). All utilize relatively high pH (approximately 12) and one contains small amounts of tartrate (6), a relatively weak complexing agent (8), in addition to lead. These modified lead stains are less liable to contaminate the surface of the section with precipitated stain products. The stain reported here differs from previous alkaline lead stains in that the chelating agent, citrate, is in sufficient excess to sequester all lead present. Lead citrate, soluble in high concentrations in basic solutions, is a chelate compound with an apparent association constant (log Ka) between ligand and lead ion of 6.5 (9). Tissue binding sites, presumably organophosphates, and other anionic species present in biological components following fixation, dehydration, and plastic embedding apparently have a greater affinity for this cation than lead citrate inasmuch as cellular and extracellular structures in the section sequester lead from the staining solution. Alkaline lead citrate solutions are less likely to contaminate sections, as no precipitates form when droplets of fresh staining solution are exposed to air for periods of up to 30 minutes. The resultant staining of the sections is of high intensity in sections of Aralditeor Epon-embedded material. Cytoplasmic membranes, ribosomes, glycogen, and nuclear material are stained (Figs. 1 to 3). STAIN SOLUTION: Lead citrate is prepared by", "title": "THE USE OF LEAD CITRATE AT HIGH pH AS AN ELECTRON-OPAQUE STAIN IN ELECTRON MICROSCOPY" } ]

[ { "docid": "2097256", "text": "BACKGROUND Aedes aegypti, the major vector of dengue viruses, often breeds in water storage containers used by households without tap water supply, and occurs in high numbers even in dense urban areas. We analysed the interaction between human population density and lack of tap water as a cause of dengue fever outbreaks with the aim of identifying geographic areas at highest risk. \n METHODS AND FINDINGS We conducted an individual-level cohort study in a population of 75,000 geo-referenced households in Vietnam over the course of two epidemics, on the basis of dengue hospital admissions (n = 3,013). We applied space-time scan statistics and mathematical models to confirm the findings. We identified a surprisingly narrow range of critical human population densities between around 3,000 to 7,000 people/km² prone to dengue outbreaks. In the study area, this population density was typical of villages and some peri-urban areas. Scan statistics showed that areas with a high population density or adequate water supply did not experience severe outbreaks. The risk of dengue was higher in rural than in urban areas, largely explained by lack of piped water supply, and in human population densities more often falling within the critical range. Mathematical modeling suggests that simple assumptions regarding area-level vector/host ratios may explain the occurrence of outbreaks. \n CONCLUSIONS Rural areas may contribute at least as much to the dissemination of dengue fever as cities. Improving water supply and vector control in areas with a human population density critical for dengue transmission could increase the efficiency of control efforts. Please see later in the article for the Editors' Summary.", "title": "Population Density, Water Supply, and the Risk of Dengue Fever in Vietnam: Cohort Study and Spatial Analysis" } ]

[ { "docid": "18816720", "text": "BACKGROUND Transmission of dengue viruses (DENV), the leading cause of arboviral disease worldwide, is known to vary through time and space, likely owing to a combination of factors related to the human host, virus, mosquito vector, and environment. An improved understanding of variation in transmission patterns is fundamental to conducting surveillance and implementing disease prevention strategies. To test the hypothesis that DENV transmission is spatially and temporally focal, we compared geographic and temporal characteristics within Thai villages where DENV are and are not being actively transmitted. \n METHODS AND FINDINGS Cluster investigations were conducted within 100 m of homes where febrile index children with (positive clusters) and without (negative clusters) acute dengue lived during two seasons of peak DENV transmission. Data on human infection and mosquito infection/density were examined to precisely (1) define the spatial and temporal dimensions of DENV transmission, (2) correlate these factors with variation in DENV transmission, and (3) determine the burden of inapparent and symptomatic infections. Among 556 village children enrolled as neighbors of 12 dengue-positive and 22 dengue-negative index cases, all 27 DENV infections (4.9% of enrollees) occurred in positive clusters (p < 0.01; attributable risk [AR] = 10.4 per 100; 95% confidence interval 1-19.8 per 100]. In positive clusters, 12.4% of enrollees became infected in a 15-d period and DENV infections were aggregated centrally near homes of index cases. As only 1 of 217 pairs of serologic specimens tested in positive clusters revealed a recent DENV infection that occurred prior to cluster initiation, we attribute the observed DENV transmission subsequent to cluster investigation to recent DENV transmission activity. Of the 1,022 female adult Ae. aegypti collected, all eight (0.8%) dengue-infected mosquitoes came from houses in positive clusters; none from control clusters or schools. Distinguishing features between positive and negative clusters were greater availability of piped water in negative clusters (p < 0.01) and greater number of Ae. aegypti pupae per person in positive clusters (p = 0.04). During primarily DENV-4 transmission seasons, the ratio of inapparent to symptomatic infections was nearly 1:1 among child enrollees. Study limitations included inability to sample all children and mosquitoes within each cluster and our reliance on serologic rather than virologic evidence of interval infections in enrollees given restrictions on the frequency of blood collections in children. \n CONCLUSIONS Our data reveal the remarkably focal nature of DENV transmission within a hyperendemic rural area of Thailand. These data suggest that active school-based dengue case detection prompting local spraying could contain recent virus introductions and reduce the longitudinal risk of virus spread within rural areas. Our results should prompt future cluster studies to explore how host immune and behavioral aspects may impact DENV transmission and prevention strategies. Cluster methodology could serve as a useful research tool for investigation of other temporally and spatially clustered infectious diseases.", "title": "Spatial and Temporal Clustering of Dengue Virus Transmission in Thai Villages" }, { "docid": "8665891", "text": "Dengue virus and its four serotypes (DENV 1-4) infect approximately 390 million people worldwide each year, with most cases in tropical and subtropical regions. Because of repeated introduction of DENV from epidemic regions and suitable weather conditions, many regions have shifted from hypo-endemicity to hyper-endemicity over recent decades. Since the first dengue outbreak in 1978, it is crucial to understand the current situation in China over nearly 40 years. The purpose of the study was to examine whether dengue in China was endemic or not, which is essential for relevant dengue control and prevention strategy implementation in China. The study, combining epidemiological characteristics of dengue from the disease notification system, phylogenetic and phylogeographic analyses, showed that all four serotypes had been detected in Guangzhou, China, which was dominated by DENV 1-2. The Maximum Likelihood tree analytic results showed that the virus detected in Guangzhou localized in different clades, except of virus of 2002 and 2003 clustered together. There existed the mutual introductions between Guangzhou and Southeast Asia. Most of the viruses were imported from Southeast Asia and the sources of outbreaks in Guangzhou mainly originated from Thailand, Indonesia, and the Philippines. The study indicates that dengue in China still remains as an imported disease, with the possibility of localization.", "title": "Dengue is still an imported disease in China: a case study in Guangzhou." }, { "docid": "42387637", "text": "RATIONALE Exposure to particulate air pollution has been related to increased hospitalization and death, particularly from cardiovascular disease. Lower blood DNA methylation content is found in processes related to cardiovascular outcomes, such as oxidative stress, aging, and atherosclerosis. \n OBJECTIVES We evaluated whether particulate pollution modifies DNA methylation in heavily methylated sequences with high representation throughout the human genome. \n METHODS We measured DNA methylation of long interspersed nucleotide element (LINE)-1 and Alu repetitive elements by quantitative polymerase chain reaction-pyrosequencing of 1,097 blood samples from 718 elderly participants in the Boston area Normative Aging Study. We used covariate-adjusted mixed models to account for within-subject correlation in repeated measures. We estimated the effects on DNA methylation of ambient particulate pollutants (black carbon, particulate matter with aerodynamic diameter < or = 2.5 microm [PM2.5], or sulfate) in multiple time windows (4 h to 7 d) before the examination. We estimated standardized regression coefficients (beta) expressing the fraction of a standard deviation change in DNA methylation associated with a standard deviation increase in exposure. \n MEASUREMENTS AND MAIN RESULTS Repetitive element DNA methylation varied in association with time-related variables, such as day of the week and season. LINE-1 methylation decreased after recent exposure to higher black carbon (beta = -0.11; 95% confidence interval [CI], -0.18 to -0.04; P = 0.002) and PM2.5 (beta = -0.13; 95% CI, -0.19 to -0.06; P < 0.001 for the 7-d moving average). In two-pollutant models, only black carbon, a tracer of traffic particles, was significantly associated with LINE-1 methylation (beta = -0.09; 95% CI, -0.17 to -0.01; P = 0.03). No association was found with Alu methylation (P > 0.12). \n CONCLUSIONS We found decreased repeated-element methylation after exposure to traffic particles. Whether decreased methylation mediates exposure-related health effects remains to be determined.", "title": "Rapid DNA methylation changes after exposure to traffic particles." }, { "docid": "11238951", "text": "Kaposi's sarcoma-associated herpesvirus (KSHV), also termed human herpesvirus type 8, is consistently identified in Kaposi's sarcoma, primary effusion lymphoma (PEL), and multicentric Castleman's disease. Here we report four cases of KSHV-bearing solid lymphomas that occurred in AIDS patients (cases 1 to 3) and in a human immunodeficiency virus (HIV)-seronegative person (case 4). The patients presented extranodal masses in the abdomen (cases 1, 3, and 4) or skin (case 2), and nodal involvement, together with Kaposi's sarcoma (case 3). The gastrointestinal tract was involved in two patients (cases 1 and 3). The patients did not develop a lymphomatous effusion. KSHV was detected in the tumor cells of all cases by immunohistochemistry and by polymerase chain reaction. Epstein-Barr virus was detected in two of the HIV-related cases. All KSHV-positive solid lymphomas exhibited PEL-like cell morphology. To investigate the relationship of these disorders to PEL and to other AIDS-associated diffuse large cell lymphomas, KSHV-positive solid lymphomas were tested for the expression of a set of genes that were previously shown by gene profiling analysis to define PEL tumor cells. The results showed that expression of this set of genes in KSHV-positive lymphomas is similar to that of PEL but distinct from KSHV-negative AIDS-associated diffuse large cell lymphomas. Because pathobiological features of KSHV-positive solid lymphomas closely mimic those of PEL, our results suggest that KSHV-positive solid lymphomas should be considered as a tissue-based variant of classical PEL, irrespective of HIV status.", "title": "Kaposi's sarcoma-associated herpesvirus/human herpesvirus type 8-positive solid lymphomas: a tissue-based variant of primary effusion lymphoma." }, { "docid": "17454301", "text": "A small, isolated outbreak of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) due to dengue virus type 2 (DEN-2) was documented in Santiago de Cuba on the island of Cuba beginning in January 1997. There were 205 DHF/DSS cases, all in persons older than age 15 years. All but three had evidence of a prior dengue infection, with the only known opportunity being the islandwide dengue virus type 1 (DEN-1) epidemic of 1977-1979. Virtually complete clinical and laboratory surveillance of overt disease was achieved. From December 1997 to January 1998, a random, age-stratified serum sample was obtained from 1,151 persons in 40 residential clusters in Santiago. Sera were tested for DEN-1 and DEN-2 neutralizing antibodies. The prevalence of DEN-2 antibodies in children age 15 years and under, born after the 1981 DEN-2 epidemic, was taken as the 1997 DEN-2 infection rate. This was adjusted slightly to accommodate observed cases, resulting in an estimated infection rate of 4.3%. Dengue fever and DHF/DSS attack rates were calculated from estimated total primary and secondary DEN-2 infections. Only 3% of 13,116 primary infections were overt. The DHF/DSS attack rate for adults of all ages was 420 per 10,000 secondary DEN-2 infections.", "title": "Epidemiologic studies on Dengue in Santiago de Cuba, 1997." }, { "docid": "21003930", "text": "BACKGROUND Long-term exposure to pollution can lead to an increase in the rate of decline of lung function, especially in older individuals and in those with chronic obstructive pulmonary disease (COPD), whereas shorter-term exposure at higher pollution levels has been implicated in causing excess deaths from ischaemic heart disease and exacerbations of COPD. We aimed to assess the effects on respiratory and cardiovascular responses of walking down a busy street with high levels of pollution compared with walking in a traffic-free area with lower pollution levels in older adults. \n METHODS In this randomised, crossover study, we recruited men and women aged 60 years and older with angiographically proven stable ischaemic heart disease or stage 2 Global initiative for Obstructive Lung Disease (GOLD) COPD who had been clinically stable for 6 months, and age-matched healthy volunteers. Individuals with ischaemic heart disease or COPD were recruited from existing databases or outpatient respiratory and cardiology clinics at the Royal Brompton & Harefield NHS Foundation Trust and age-matched healthy volunteers using advertising and existing databases. All participants had abstained from smoking for at least 12 months and medications were taken as recommended by participants' doctors during the study. Participants were randomly assigned by drawing numbered disks at random from a bag to do a 2 h walk either along a commercial street in London (Oxford Street) or in an urban park (Hyde Park). Baseline measurements of participants were taken before the walk in the hospital laboratory. During each walk session, black carbon, particulate matter (PM) concentrations, ultrafine particles, and nitrogen dioxide (NO2) concentrations were measured. \n FINDINGS Between October, 2012, and June, 2014, we screened 135 participants, of whom 40 healthy volunteers, 40 individuals with COPD, and 39 with ischaemic heart disease were recruited. Concentrations of black carbon, NO2, PM10, PM2.5, and ultrafine particles were higher on Oxford Street than in Hyde Park. Participants with COPD reported more cough (odds ratio [OR] 1·95, 95% CI 0·96-3·95; p<0·1), sputum (3·15, 1·39-7·13; p<0·05), shortness of breath (1·86, 0·97-3·57; p<0·1), and wheeze (4·00, 1·52-10·50; p<0·05) after walking down Oxford Street compared with Hyde Park. In all participants, irrespective of their disease status, walking in Hyde Park led to an increase in lung function (forced expiratory volume in the first second [FEV1] and forced vital capacity [FVC]) and a decrease in pulse wave velocity (PWV) and augmentation index up to 26 h after the walk. By contrast, these beneficial responses were attenuated after walking on Oxford Street. In participants with COPD, a reduction in FEV1 and FVC, and an increase in R5-20 were associated with an increase in during-walk exposure to NO2, ultrafine particles and PM2.5, and an increase in PWV and augmentation index with NO2 and ultrafine particles. In healthy volunteers, PWV and augmentation index were associated both with black carbon and ultrafine particles. \n INTERPRETATION Short-term exposure to traffic pollution prevents the beneficial cardiopulmonary effects of walking in people with COPD, ischaemic heart disease, and those free from chronic cardiopulmonary diseases. Medication use might reduce the adverse effects of air pollution in individuals with ischaemic heart disease. Policies should aim to control ambient levels of air pollution along busy streets in view of these negative health effects. \n FUNDING British Heart Foundation.", "title": "Respiratory and cardiovascular responses to walking down a traffic-polluted road compared with walking in a traffic-free area in participants aged 60 years and older with chronic lung or heart disease and age-matched healthy controls: a randomised, crossover study" }, { "docid": "23304931", "text": "PURPOSE Diffuse large B-cell lymphoma (DLBCL) represents a clinically heterogeneous disease. Models based on immunohistochemistry predict clinical outcome. These include subdivision into germinal center (GC) versus non-GC subtypes; proliferation index (measured by expression of Ki-67), and expression of BCL-2, FOXP1, or B-lymphocyte-induced maturation protein (Blimp-1)/PRDM1. We sought to determine whether immunohistochemical analyses of biopsies from patients with DLBCL having HIV infection are similarly relevant for prognosis. \n PATIENTS AND METHODS We examined 81 DLBCLs from patients with AIDS in AMC010 (cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP] v CHOP-rituximab) and AMC034 (etoposide, doxorubicin, vincristine, prednisone, and dose-adjusted cyclophosphamide plus rituximab concurrent v sequential) clinical trials and compared the immunophenotype with survival data, Epstein-Barr virus (EBV) positivity, and CD4 counts. \n RESULTS The GC and non-GC subtypes of DLBCL did not differ significantly with respect to overall survival or CD4 count at cancer presentation. EBV could be found in both subtypes of DLBCL, although less frequently in the GC subtype, and did not affect survival. Expression of FOXP1, Blimp-1/PRDM1, or BCL-2 was not correlated with the outcome in patients with AIDS-related DLBCL. \n CONCLUSION These data indicate that with current treatment strategies for lymphoma and control of HIV infection, commonly used immunohistochemical markers may not be clinically relevant in HIV-infected patients with DLBCL. The only predictive immunohistochemical marker was found to be Ki-67, where a higher proliferation index was associated with better survival, suggesting a better response to therapy in patients whose tumors had higher proliferation rates.", "title": "Immunophenotypic analysis of AIDS-related diffuse large B-cell lymphoma and clinical implications in patients from AIDS malignancies consortium clinical trials 010 and 034" }, { "docid": "35962023", "text": "Recent studies suggest a close relationship between cell metabolism and apoptosis. We have evaluated changes in lipid metabolism on permeabilized hepatocytes treated with truncated Bid (tBid) in the presence of caspase inhibitors and exogenous cytochrome c. The measurement of β-oxidation flux by labeled palmitate demonstrates that tBid inhibits β-oxidation, thereby resulting in the accumulation of palmitoyl-coenzyme A (CoA) and depletion of acetyl-carnitine and acylcarnitines, which is pathognomonic for inhibition of carnitine palmitoyltransferase-1 (CPT-1). We also show that tBid decreases CPT-1 activity by a mechanism independent of both malonyl-CoA, the key inhibitory molecule of CPT-1, and Bak and/or Bax, but dependent on cardiolipin decrease. Overexpression of Bcl-2, which is able to interact with CPT-1, counteracts the effects exerted by tBid on β-oxidation. The unexpected role of tBid in the regulation of lipid β-oxidation suggests a model in which tBid-induced metabolic decline leads to the accumulation of toxic lipid metabolites such as palmitoyl-CoA, which might become participants in the apoptotic pathway.", "title": "tBid induces alterations of mitochondrial fatty acid oxidation flux by malonyl-CoA-independent inhibition of carnitine palmitoyltransferase-1" }, { "docid": "3716075", "text": "BACKGROUND Dengue is the most common arbovirus infection globally, but its burden is poorly quantified. We estimated dengue mortality, incidence, and burden for the Global Burden of Disease Study 2013. \n METHODS We modelled mortality from vital registration, verbal autopsy, and surveillance data using the Cause of Death Ensemble Modelling tool. We modelled incidence from officially reported cases, and adjusted our raw estimates for under-reporting based on published estimates of expansion factors. In total, we had 1780 country-years of mortality data from 130 countries, 1636 country-years of dengue case reports from 76 countries, and expansion factor estimates for 14 countries. \n FINDINGS We estimated an average of 9221 dengue deaths per year between 1990 and 2013, increasing from a low of 8277 (95% uncertainty estimate 5353-10 649) in 1992, to a peak of 11 302 (6790-13 722) in 2010. This yielded a total of 576 900 (330 000-701 200) years of life lost to premature mortality attributable to dengue in 2013. The incidence of dengue increased greatly between 1990 and 2013, with the number of cases more than doubling every decade, from 8·3 million (3·3 million-17·2 million) apparent cases in 1990, to 58·4 million (23·6 million-121·9 million) apparent cases in 2013. When accounting for disability from moderate and severe acute dengue, and post-dengue chronic fatigue, 566 000 (186 000-1 415 000) years lived with disability were attributable to dengue in 2013. Considering fatal and non-fatal outcomes together, dengue was responsible for 1·14 million (0·73 million-1·98 million) disability-adjusted life-years in 2013. \n INTERPRETATION Although lower than other estimates, our results offer more evidence that the true symptomatic incidence of dengue probably falls within the commonly cited range of 50 million to 100 million cases per year. Our mortality estimates are lower than those presented elsewhere and should be considered in light of the totality of evidence suggesting that dengue mortality might, in fact, be substantially higher. \n FUNDING Bill & Melinda Gates Foundation.", "title": "The global burden of dengue: an analysis from the Global Burden of Disease Study 2013." }, { "docid": "24980622", "text": "PURPOSE To investigate hypoxia measured by pimonidazole binding, glucose transporter 1 (GLUT1) and carbonic anhydrase IX (CA-IX) expression, proliferation, and vascularity in liver metastases of colorectal cancer and to compare GLUT1 and CA-IX expression in corresponding primary tumors. \n METHODS AND MATERIALS Twenty-five patients with liver metastases of colorectal cancer, planned for metastasectomy, were included. The hypoxia marker pimonidazole and proliferation marker iododeoxyuridine were administered before surgery. After immunofluorescent staining of the frozen metastases, pimonidazole binding, vascularity, and proliferation were analyzed quantitatively. Thirteen paraffin-embedded primary tumors were stained immunohistochemically for GLUT1 and CA-IX expression, which was analyzed semiquantitatively in primary tumors and corresponding liver metastases. \n RESULTS In liver metastases, pimonidazole binding showed a pattern consistent with diffusion-limited hypoxia. The mean pimonidazole-positive fraction was 0.146; the mean distance from vessels to pimonidazole-positive areas was 80 microm. When expressed, often co-localization was observed between pimonidazole binding and GLUT1 or CA-IX expression, but microregional areas of mismatch were also observed. No correlation between the level of pimonidazole binding and GLUT1 or CA-IX expression was observed. In some patients, a large fraction (up to 30%) of proliferating cells was present in pimonidazole-stained areas. Expression of CA-IX in primary tumors and metastases showed a significant correlation, which was absent for GLUT1 expression. \n CONCLUSIONS Compared with other tumor types, liver metastases of colorectal cancer contain large amounts of hypoxic cells. The lack of correlation with pimonidazole binding brings into question the value of GLUT1 and CA-IX as endogenous markers of hypoxia.", "title": "Hypoxia in relation to vasculature and proliferation in liver metastases in patients with colorectal cancer." }, { "docid": "9599194", "text": "With the recent availability of complete genomic sequences of many organisms, high-throughput and cost-efficient systems for gene cloning and functional analysis are in great demand. Although site-specific recombination-based cloning systems, such as Gateway cloning technology, are extremely useful for efficient transfer of DNA fragments into multiple destination vectors, the two-step cloning process is time consuming and expensive. Here, we report a zero background TA cloning system that provides simple and high-efficiency direct cloning of PCR-amplified DNA fragments with almost no self-ligation. The improved T-vector system takes advantage of the restriction enzyme XcmI to generate a T-overhang after digestion and the negative selection marker gene ccdB to eliminate the self-ligation background after transformation. We demonstrate the feasibility and flexibility of the technology by developing a set of transient and stable transformation vectors for constitutive gene expression, gene silencing, protein tagging, protein subcellular localization detection, and promoter fragment activity analysis in plants. Because the system can be easily adapted for developing specialized expression vectors for other organisms, zero background TA provides a general, cost-efficient, and high-throughput platform that complements the Gateway cloning system for gene cloning and functional genomics.", "title": "A versatile zero background T-vector system for gene cloning and functional genomics." }, { "docid": "8246090", "text": "Ion channels are classically understood to regulate the flux of ions across the plasma membrane in response to a variety of environmental and intracellular cues. Ion channels serve a number of functions in intracellular membranes as well. These channels may be temporarily localized to intracellular membranes as a function of their biosynthetic or secretory pathways, i.e., en route to their destination location. Intracellular membrane ion channels may also be located in the endocytic pathways, either being recycled back to the plasma membrane or targeted to the lysosome for degradation. Several channels do participate in intracellular signal transduction; the most well known example is the inositol 1,4,5-trisphosphate receptor (IP(3)R) in the endoplasmic reticulum. Some organellar intracellular membrane channels are required for the ionic homeostasis of their residing organelles. Several newly-discovered intracellular membrane Ca(2+) channels actually play active roles in membrane trafficking. Transient receptor potential (TRP) proteins are a superfamily (28 members in mammal) of Ca(2+)-permeable channels with diverse tissue distribution, subcellular localization, and physiological functions. Almost all mammalian TRP channels studied thus far, like their ancestor yeast TRP channel (TRPY1) that localizes to the vacuole compartment, are also (in addition to their plasma membrane localization) found to be localized to intracellular membranes. Accumulated evidence suggests that intracellularly-localized TRP channels actively participate in regulating membrane traffic, signal transduction, and vesicular ion homeostasis. This review aims to provide a summary of these recent works. The discussion will also be extended to the basic membrane and electrical properties of the TRP-residing compartments.", "title": "TRP channels of intracellular membranes." }, { "docid": "37643601", "text": "Many viruses go through a maturation step in the final stages of assembly before being transmitted to another host. The maturation process of flaviviruses is directed by the proteolytic cleavage of the precursor membrane protein (prM), turning inert virus into infectious particles. We have determined the 2.2 angstrom resolution crystal structure of a recombinant protein in which the dengue virus prM is linked to the envelope glycoprotein E. The structure represents the prM-E heterodimer and fits well into the cryo-electron microscopy density of immature virus at neutral pH. The pr peptide beta-barrel structure covers the fusion loop in E, preventing fusion with host cell membranes. The structure provides a basis for identifying the stages of its pH-directed conformational metamorphosis during maturation, ending with release of pr when budding from the host.", "title": "The flavivirus precursor membrane-envelope protein complex: structure and maturation." }, { "docid": "1583134", "text": "Autoimmune polyglandular syndrome type I (APS 1, also called APECED) is an autosomal-recessive disorder that maps to human chromosome 21q22.3 between markers D21S49 and D21S171 by linkage studies. We have isolated a novel gene from this region, AIRE (autoimmune regulator), which encodes a protein containing motifs suggestive of a transcription factor including two zinc-finger (PHD-finger) motifs, a proline-rich region and three LXXLL motifs. Two mutations, a C→T substitution that changes the Arg 257 (CGA) to a stop codon (TGA) and an A→G substitution that changes the Lys 83 (AAG) to a Glu codon (GAG), were found in this novel gene in Swiss and Finnish APECED patients. The Arg257stop (R257X) is the predominant mutation in Finnish APECED patients, accounting for 10/12 alleles studied. These results indicate that this gene is responsible for the pathogenesis of APECED. The identification of the gene defective in APECED should facilitate the genetic diagnosis and potential treatment of the disease and further enhance our general understanding of the mechanisms underlying autoimmune diseases.", "title": "Positional cloning of the APECED gene" }, { "docid": "19854744", "text": "Using an antiserum raised to a recombinant coxsackie virus B3 capsid protein, VP1, an immunocytochemical technique was developed which was capable of detecting the presence of all coxsackie B viruses in formalin fixed paraffin embedded infected tissue culture cells. This technique was tested on autopsy heart and pancreas from 21 patients who were thought to have died of acute coxsackievirus B myocarditis. Cardiac myocytes were positive for the VP1 protein in 12 of 20 cases where the heart was available for study. Insulitis was present in the pancreas in seven of these cases and in all seven islet endocrine cells containing VP1 were found. VP1 was only rarely found in exocrine pancreas. In heart and pancreas, cells shown to contain VP1 usually showed signs of necrosis. Autopsy pancreases from 88 patients who had died at clinical presentation of Type 1 (insulin-dependent) diabetes mellitus showed no evidence of the presence of VP1. The continuing destruction of insulin-secreting B cells seen at the time of death in the diabetic pancreas is unlikely to be due to a direct cytopathic effect of a coxsackie B virus. However, this study does not exclude the possibility that a persistent infection of B cells by a defective enterovirus may result in their destruction by an autoimmune mechanism.", "title": "A search for the presence of the enteroviral capsid protein VP1 in pancreases of patients with Type 1 (insulin-dependent) diabetes and pancreases and hearts of infants who died of coxsackieviral myocarditis" }, { "docid": "25134146", "text": "Hepatitis C virus (HCV) is frequently encountered in human immunodeficiency virus (HIV)-infected patients because of common routes of transmission. Previous studies suggested that HIV infection impaired the natural course of chronic hepatitis C, with a more rapid progression to cirrhosis. However, these studies did not assess the HIV infection impact on chronic hepatitis C by taking into account the risk factors for liver fibrosis progression: alcohol, sex, age at the contamination, and duration of HCV infection. We studied liver biopsy specimens of 2 groups of 58 patients that were infected by both HCV and HIV or by HCV alone. The 2 groups were matched according those risk factors, and liver biopsy responses were evaluated with the METAVIR items. The METAVIR activity was higher in HIV-positive than HIV-negative patients. Cirrhosis was more frequent: (1) in HIV-positive patients with CD4 < or = 200 cells/microL (45%) than in HIV-negative patients (10%) (P = .003), (2) in HIV-positive patients with CD4 < or = 200 cells/microL (45%) than in HIV-positive patients with CD4 > 200 cells/microL (17%) (P = .04). These differences, which were linked to HIV status, might be related to the enhanced HCV replication during HIV infection or other immune mechanisms that need further studies.", "title": "Impact of human immunodeficiency virus infection on the histological features of chronic hepatitis C: a case-control study. The MULTIVIRC group." }, { "docid": "28243325", "text": "A novel mammalian regulatory system was created by using the Escherichia coli lac repressor. The lac repressor was converted into a mammalian transcriptional activator by modifying the lac repressor coding region to include a nuclear localization signal from the simian virus 40 (SV40) large tumor antigen and the transcription activation domain from the herpes simplex virus type 1 virion protein 16. The lac activator protein (LAP) fusions were potent activators of several promoters containing lac operator sequences positioned either upstream or downstream of the transcription unit. A single lac operator allowed for transactivation, whereas multiple operators acted synergistically when separated by a small distance. Promoters containing 14 or 21 operator sequences were induced at least 1,000-fold in response to LAP, reaching levels of activity 20 to 30 times greater than that of the SV40 early promoter in HeLa cells. Activation was strongly inhibited by isopropyl-beta-D-thiogalactoside (IPTG), indicating that LAP retained the functions needed for allosteric regulation. LAP was bifunctional, also acting as a repressor of expression of an SV40 promoter containing an operator immediately downstream of the TATA box. Finally, genetic selection schemes were developed such that LAP-expressing cell lines can be generated at high frequency from either established or primary cells in culture.", "title": "Conversion of the lac repressor into an allosterically regulated transcriptional activator for mammalian cells." }, { "docid": "22414304", "text": "There is little information about treatment outcome in patients with smear-negative pulmonary tuberculosis (PTB) or extrapulmonary tuberculosis (EPTB) treated under routine programme conditions in subsaharan Africa. A prospective study was carried out to determine treatment outcome in an unselected cohort of TB patients admitted to Zomba General Hospital, Malawi. Eight hundred and twenty-seven adult TB patients (451 men and 376 women) were registered between 1 July and 31 December 1995. Standardized treatment outcomes of treatment completion, death, default, and transfer to another district were assessed in relation to type of TB, human immunodeficiency virus (HIV) serostatus, age and gender. Two hundred and fifty-four patients (31%) died by the end of treatment, half of the deaths occurring in the first month. Death rates were 19% among 386 patients with smear-positive PTB, 46% among 211 patients with smear-negative PTB, and 37% among 230 patients with EPTB; 77% of the patients were HIV seropositive. Among new patients, HIV-positive patients had higher death rates than HIV-negative patients (hazard ratio [HR] 2.5; 95% confidence interval [95% CI] 1.6-3.8). Smear-negative patients had the highest death rates (HR 3.9; 95% CI 2.7-5.5 compared to smear-positive patients), followed by EPTB patients (HR 2.6, 95% CI 1.8-3.7 compared to smear-positive patients). Death rates increased with age but were similar in men and women. Adult patients in Malawi with smear-negative PTB and EPTB have low treatment completion and high death rates, related to high levels of HIV infection. National TB control programmes in areas of high HIV prevalence should no longer ignore treatment outcomes in patients with smear-negative PTB or EPTB.", "title": "Treatment outcome of an unselected cohort of tuberculosis patients in relation to human immunodeficiency virus serostatus in Zomba Hospital, Malawi." }, { "docid": "32827351", "text": "Aqueous solutions of lead salts (1, 2) and saturated solutions of lead hydroxide (1) have been used as stains to enhance the electron-scattering properties of components of biological materials examined in the electron microscope. Saturated solutions of lead hydroxide (1), while staining more intensely than either lead acetate or monobasic lead acetate (l , 2), form insoluble lead carbonate upon exposure to air. The avoidance of such precipitates which contaminate surfaces of sections during staining has been the stimulus for the development of elaborate procedures for exclusion of air or carbon dioxide (3, 4). Several modifications of Watson's lead hydroxide stain (1) have recently appeared (5-7). All utilize relatively high pH (approximately 12) and one contains small amounts of tartrate (6), a relatively weak complexing agent (8), in addition to lead. These modified lead stains are less liable to contaminate the surface of the section with precipitated stain products. The stain reported here differs from previous alkaline lead stains in that the chelating agent, citrate, is in sufficient excess to sequester all lead present. Lead citrate, soluble in high concentrations in basic solutions, is a chelate compound with an apparent association constant (log Ka) between ligand and lead ion of 6.5 (9). Tissue binding sites, presumably organophosphates, and other anionic species present in biological components following fixation, dehydration, and plastic embedding apparently have a greater affinity for this cation than lead citrate inasmuch as cellular and extracellular structures in the section sequester lead from the staining solution. Alkaline lead citrate solutions are less likely to contaminate sections, as no precipitates form when droplets of fresh staining solution are exposed to air for periods of up to 30 minutes. The resultant staining of the sections is of high intensity in sections of Aralditeor Epon-embedded material. Cytoplasmic membranes, ribosomes, glycogen, and nuclear material are stained (Figs. 1 to 3). STAIN SOLUTION: Lead citrate is prepared by", "title": "THE USE OF LEAD CITRATE AT HIGH pH AS AN ELECTRON-OPAQUE STAIN IN ELECTRON MICROSCOPY" } ]

[ { "docid": "23349986", "text": "CONTEXT Dexamethasone is widely used to prevent postoperative nausea and vomiting (PONV) in pediatric tonsillectomy. \n OBJECTIVE To assess whether dexamethasone dose-dependently reduces the risk of PONV at 24 hours after tonsillectomy. \n DESIGN, SETTING, AND PATIENTS Randomized placebo-controlled trial conducted among 215 children undergoing elective tonsillectomy at a major public teaching hospital in Switzerland from February 2005 to December 2007. \n INTERVENTIONS Children were randomly assigned to receive dexamethasone (0.05, 0.15, or 0.5 mg/kg) or placebo intravenously after induction of anesthesia. Acetaminophen-codeine and ibuprofen were given as postoperative analgesia. Follow-up continued until the 10th postoperative day. \n MAIN OUTCOME MEASURES The primary end point was prevention of PONV at 24 hours; secondary end points were decrease in the need for ibuprofen at 24 hours and evaluation of adverse effects. \n RESULTS At 24 hours, 24 of 54 participants who received placebo (44%; 95% confidence interval [CI], 31%-59%) had experienced PONV compared with 20 of 53 (38%; 95% CI, 25%-52%), 13 of 54 (24%; 95% CI, 13%-38%), and 6 of 52 (12%; 95% CI, 4%-23%) who received dexamethasone at 0.05, 0.15, and 0.5 mg/kg, respectively (P<.001 for linear trend). Children who received dexamethasone received significantly less ibuprofen. There were 26 postoperative bleeding episodes in 22 children. Two of 53 (4%; 95% CI, 0.5%-13%) children who received placebo had bleeding compared with 6 of 53 (11%; 95% CI, 4%-23%), 2 of 51 (4%; 95% CI, 0.5%-13%), and 12 of 50 (24%; 95% CI, 13%-38%) who received dexamethasone at 0.05, 0.15, and 0.5 mg/kg, respectively (P = .003). Dexamethasone, 0.5 mg/kg, was associated with the highest bleeding risk (adjusted relative risk, 6.80; 95% CI, 1.77-16.5). Eight children had to undergo emergency reoperation because of bleeding, all of whom had received dexamethasone. The trial was stopped early for safety reasons. \n CONCLUSION In this study of children undergoing tonsillectomy, dexamethasone decreased the risk of PONV dose dependently but was associated with an increased risk of postoperative bleeding. \n TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00403806.", "title": "Dexamethasone and risk of nausea and vomiting and postoperative bleeding after tonsillectomy in children: a randomized trial." } ]

[ { "docid": "36288526", "text": "OBJECTIVE The effects of hydroxyethyl starch on bleeding after cardiopulmonary bypass were determined. \n METHODS A meta-analysis was performed of postoperative blood loss in randomized clinical trials of hydroxyethyl starch versus albumin for fluid management in adult cardiopulmonary bypass surgery. Impacts of hydroxyethyl starch molecular weight and molar substitution were assessed. Randomized trials directly comparing different hydroxyethyl starch solutions were also included. \n RESULTS Eighteen trials with 970 total patients were included. Compared with albumin, hydroxyethyl starch increased postoperative blood loss by 33.3% of a pooled SD (95% confidence interval, 18.2%-48.3%; P < .001). Risk of reoperation for bleeding was more than doubled by hydroxyethyl starch (relative risk, 2.24; 95% confidence interval, 1.14-4.40; P = .020). Hydroxyethyl starch increased transfusion of red blood cells by 28.4% of a pooled SD (95% confidence interval, 12.2%-44.6%; P < .001), of fresh-frozen plasma by 30.6% (95% confidence interval, 8.0%-53.1%; P = .008), and of platelets by 29.8% (95% confidence interval, 3.4%-56.2%; P = .027). None of these effects differed significantly between hydroxyethyl starch 450/0.7 and 200/0.5. Insufficient data were available for hydroxyethyl starch 130/0.4 versus albumin; however, no significant differences were detected in head-to-head comparisons of hydroxyethyl starch 130/0.4 with 200/0.5. Albumin improved hemodynamics. There were no differences in fluid balance, ventilator time, intensive care unit stay, or mortality. \n CONCLUSIONS Hydroxyethyl starch increased blood loss, reoperation for bleeding, and blood product transfusion after cardiopulmonary bypass. There was no evidence that these risks could be mitigated by lower molecular weight and substitution.", "title": "Effect of hydroxyethyl starch on bleeding after cardiopulmonary bypass: a meta-analysis of randomized trials." }, { "docid": "24211561", "text": "We evaluated the effect of dexamethasone on vomiting after elective tonsillectomy in 133 healthy children aged 2-12 yr in a randomized, stratified, blocked, double-blind, placebo-controlled study. General anesthesia was induced by inhalation of N2O and halothane or intravenously (IV) with propofol. Anesthesia was maintained with N2O and halothane. Dexamethasone 150 micrograms/kg up to a maximum dose of 8 mg, or placebo, was administered IV before surgery. All patients received 1.5 mg/kg codeine intramuscularly (IM) intraoperatively. Perioperative IV fluids, management of emesis, postoperative pain and hospital discharge criteria were all standardized. The groups were similar with respect to number, age, weight, length of surgery, and estimated intraoperative blood loss. Dexamethasone reduced the overall incidence of vomiting from 72% (placebo) to 40% (P < 0.001). Vomiting, both in-hospital and postdischarge, was decreased by the prophylactic administration of dexamethasone. Each episode of in-hospital vomiting prolonged discharge by 13 +/- 2 min, mean +/- SD (P < 0.001). In conclusion, dexamethasone markedly decreased vomiting by healthy children after elective tonsillectomy in an ambulatory hospital setting.", "title": "Dexamethasone decreases vomiting by children after tonsillectomy." }, { "docid": "15948830", "text": "Postoperative vomiting (POV) remains one of the commonest causes of significant morbidity after tonsillectomy in children. A variety of prophylactic anti-emetic interventions have been reported, but there has only been a limited systematic review in this patient group. A systematic search was performed by using Cochrane Controlled Trials Register, MEDLINE and EMBASE to identify double-blind, randomized, placebo-controlled trials of prophylactic anti-emetic interventions in children undergoing tonsillectomy, with or without adenoidectomy. The outcome of interest was POV in the first 24 h. Summary estimates of the effect of each prophylactic anti-emetic strategy were derived using fixed effect meta-analysis. Where appropriate, dose-response effects were estimated using logistic regression and 22 articles were identified. Good evidence was found for the prophylactic anti-emetic effect of dexamethasone [odds ratio (OR) 0.23, 95% CI 0.16-0.33], and the serotinergic antagonists ondansetron (OR 0.36, 95% CI 0.29-0.46), granisetron (OR 0.11, 95% CI 0.06-0.19), tropisetron (OR 0.15, 95% CI 0.06-0.35) and dolasetron (OR 0.25, 95% CI 0.1-0.59). Metoclopramide was also found to be efficacious (OR 0.51, 95% CI 0.34-0.77). There is not sufficient evidence to suggest that dimenhydrinate, perphenazine or droperidol, in the doses studied, are efficacious, nor were gastric aspiration or acupuncture. In conclusion, dexamethasone and the anti-serotinergic agents appear to be the most effective agents for the prophylaxis for POV in children undergoing tonsillectomy.", "title": "Prophylaxis of postoperative vomiting in children undergoing tonsillectomy: a systematic review and meta-analysis." }, { "docid": "23783727", "text": "AIMS patients with diabetes mellitus (DM) have high platelet reactivity and are at increased risk of ischaemic events and bleeding post-acute coronary syndromes (ACS). In the PLATelet inhibition and patient Outcomes (PLATO) trial, ticagrelor reduced the primary composite endpoint of cardiovascular death, myocardial infarction, or stroke, but with similar rates of major bleeding compared with clopidogrel. We aimed to investigate the outcome with ticagrelor vs. clopidogrel in patients with DM or poor glycaemic control. \n METHODS AND RESULTS we analysed patients with pre-existing DM (n = 4662), including 1036 patients on insulin, those without DM (n = 13 951), and subgroups based on admission levels of haemoglobin A1c (HbA1c; n = 15 150). In patients with DM, the reduction in the primary composite endpoint (HR: 0.88, 95% CI: 0.76-1.03), all-cause mortality (HR: 0.82, 95% CI: 0.66-1.01), and stent thrombosis (HR: 0.65, 95% CI: 0.36-1.17) with no increase in major bleeding (HR: 0.95, 95% CI: 0.81-1.12) with ticagrelor was consistent with the overall cohort and without significant diabetes status-by-treatment interactions. There was no heterogeneity between patients with or without ongoing insulin treatment. ticagrelor reduced the primary endpoint, all-cause mortality, and stent thrombosis in patients with HbA1c above the median (HR: 0.80, 95% CI: 0.70-0.91; HR: 0.78, 95% CI: 0.65-0.93; and HR: 0.62, 95% CI: 0.39-1.00, respectively) with similar bleeding rates (HR: 0.98, 95% CI: 0.86-1.12). \n CONCLUSION ticagrelor, when compared with clopidogrel, reduced ischaemic events in ACS patients irrespective of diabetic status and glycaemic control, without an increase in major bleeding events.", "title": "Ticagrelor vs. clopidogrel in patients with acute coronary syndromes and diabetes: a substudy from the PLATelet inhibition and patient Outcomes (PLATO) trial" }, { "docid": "20645335", "text": "OBJECTIVE To systematically review and integrate data on the neurodevelopmental outcome of children after administration of a single course of antenatal corticosteroids for threatened preterm labor. \n DATA SOURCES MEDLINE, Scopus, CENTRAL, and www.clinicaltrials.gov (inception to August 2014) using combinations of the terms \"prenatal,\" \"antenatal,\" \"cortico*,\" \"*steroid*,\" \"betamethasone,\" \"dexamethasone,\" \"neurodevelopment*,\" \"*development*,\" and \"follow-up. \" We perused the references of the retrieved articles. \n METHODS OF STUDY SELECTION We included randomized and nonrandomized trials reporting on the neurodevelopmental outcomes of children whose mothers were administered a single course of betamethasone or dexamethasone antenatally for threatened preterm birth as opposed to placebo or no treatment. TABULATION, INTEGRATION, AND RESULTS Summary risk ratio (RR) was calculated for dichotomous data; standardized mean difference was calculated for trials that measured the same outcome but used different methods. Heterogeneity was assessed using the I statistic. Sensitivity and subgroup analyses were planned according to study design, specific steroid, and mean gestational age at birth. A single course of antenatal corticosteroids was associated with reduced risk for cerebral palsy (seven studies; treated: 390 of 5,199, untreated: 146 of 1,379; RR 0.678, 95% confidence interval [CI] 0.564-0.815), psychomotor development index less than 70 (two studies; treated: 783 of 3,049, untreated: 258 of 969; RR 0.829, 95% CI 0.737-0.933), and severe disability (five studies; treated: 1,567 of 4,840, untreated: 475 of 1,211; RR 0.787, 95% CI 0.729-0.850). Steroid treatment increased the rates of intact survival (six studies; treated: 1,082 of 2,013, untreated: 273 of 561; RR 1.186, 95% CI 1.056-1.332). Betamethasone was found to significantly decrease the risk for severe disability and increase the rate of intact survival. Dexamethasone increased the rate of intact survival; however, data for dexametasone and the other planned subgroup analyses were limited (fewer than 1,000 children at most). The major limitations involved inclusion of nonrandomized studies and scarcity of data on finer neurodevelopmental outcomes. \n CONCLUSION A single course of antenatal corticosteroids in women at high risk for preterm birth appears to improve most neurodevelopmental outcomes in offspring born before 34 weeks of gestation.", "title": "Neurodevelopmental Outcome After a Single Course of Antenatal Steroids in Children Born Preterm: A Systematic Review and Meta-analysis." }, { "docid": "20130904", "text": "BACKGROUND Gastric bypass patients with a range of disturbed eating patterns before surgery may be at risk of returning to old patterns postoperatively. Recent research has shown that binge eating is common among the obese before surgery as well as in the postoperative maintenance phase and appears to be linked to poorer outcome. Although \"grazing\" behavior has not been specifically studied, it is also a high-risk pattern. This paper is a descriptive investigation summarizing postoperative eating patterns in a group of patients. \n METHODS Patients completed self-report questionnaires before surgery and were seen for a preoperative mental health evaluation with particular focus on assessing eating patterns. Patients with high-risk eating patterns, both binge eating and \"grazing\", were identified, invited to attend a post-surgery therapy group, and were given additional follow-up questionnaires regarding postoperative eating patterns. \n RESULTS Consistent with recent studies, many high-risk patients reported recurrent loss of control over eating and, in some cases, subsequent weight gain. Although no longer able to eat large amounts, \"grazing\" became a more common pattern, appearing >or=6 months following surgery. \n CONCLUSION Different forms of overeating need to be assessed in this population, focusing on the subjective loss of control rather than on the quantity consumed. Although many patients do not meet strict criteria for binge eating disorder before surgery, these \"grazers\" are also high-risk. Former binge eaters often turn into \"grazers\" following surgery. Interventions are needed for at-risk patients.", "title": "\"Grazing\": a high-risk behavior." }, { "docid": "14973286", "text": "A small proportion of patients with deep vein thrombosis develop recurrent venous thromboembolic complications or bleeding during anticoagulant treatment. These complications may occur more frequently if these patients have concomitant cancer. This prospective follow-up study sought to determine whether in thrombosis patients those with cancer have a higher risk for recurrent venous thromboembolism or bleeding during anticoagulant treatment than those without cancer. Of the 842 included patients, 181 had known cancer at entry. The 12-month cumulative incidence of recurrent thromboembolism in cancer patients was 20.7% (95% CI, 15.6%-25.8%) versus 6.8% (95% CI, 3.9%- 9.7%) in patients without cancer, for a hazard ratio of 3.2 (95% CI, 1.9-5.4) The 12-month cumulative incidence of major bleeding was 12.4% (95% CI, 6.5%-18.2%) in patients with cancer and 4.9% (95% CI, 2.5%-7.4%) in patients without cancer, for a hazard ratio of 2.2 (95% CI, 1.2-4.1). Recurrence and bleeding were both related to cancer severity and occurred predominantly during the first month of anticoagulant therapy but could not be explained by sub- or overanticoagulation. Cancer patients with venous thrombosis are more likely to develop recurrent thromboembolic complications and major bleeding during anticoagulant treatment than those without malignancy. These risks correlate with the extent of cancer. Possibilities for improvement using the current paradigms of anticoagulation seem limited and new treatment strategies should be developed.", "title": "Recurrent venous thromboembolism and bleeding complications during anticoagulant treatment in patients with cancer and venous thrombosis." }, { "docid": "44384384", "text": "AIMS While randomized clinical trials have compared clopidogrel with higher potency adenosine diphosphate (ADP) receptor inhibitors among patients with acute myocardial infarction, little is known about the frequency, effectiveness and safety of switching between ADP receptor inhibitors in routine clinical practice. \n METHODS AND RESULTS We studied 11,999 myocardial infarction patients treated with percutaneous coronary intervention at 230 hospitals from April 2010 to October 2012 in the TRANSLATE-ACS study. Multivariable Cox regression was used to compare six-month post-discharge risks of major adverse cardiovascular events (MACE: death, myocardial infarction, stroke, or unplanned revascularization) and Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-defined bleeding between in-hospital ADP receptor inhibitor switching versus continuation of the initially selected therapy. Among 8715 patients treated initially with clopidogrel, 994 (11.4%) were switched to prasugrel or ticagrelor; switching occurred primarily after percutaneous coronary intervention (60.9%) and at the time of hospital discharge (26.7%). Among 3284 patients treated initially with prasugrel or ticagrelor, 448 (13.6%) were switched to clopidogrel; 48.2% of switches occurred after percutaneous coronary intervention and 48.0% at hospital discharge. Switching to prasugrel or ticagrelor was not associated with increased bleeding when compared with continuation on clopidogrel (2.7% vs. 3.3%, adjusted hazard ratio 0.96, 95% confidence interval 0.64-1.42, p=0.82). Switching from prasugrel or ticagrelor to clopidogrel was not associated with increased MACE (8.9% vs. 7.7%, adjusted hazard ratio 1.06, 95% confidence interval 0.75-1.49, p=0.76) when compared with continuation on the higher potency agent. \n CONCLUSIONS In-hospital ADP receptor inhibitor switching occurs in more than one in 10 myocardial infarction patients in contemporary practice. In this observational study, ADP receptor inhibitor switching does not appear to be significantly associated with increased hazard of MACE or bleeding.", "title": "In-hospital switching between adenosine diphosphate receptor inhibitors in patients with acute myocardial infarction treated with percutaneous coronary intervention: Insights into contemporary practice from the TRANSLATE-ACS study." }, { "docid": "44827480", "text": "BACKGROUND Few data exist about the implementation of contemporary oral antiplatelet treatment guidelines in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). \n METHODS GReek AntiPlatelet rEgistry (GRAPE), initiated on January 2012, is a prospective, observational, multicenter cohort study focusing on contemporary use of P2Y12 inhibitors. In 1434 patients we evaluated appropriateness of P2Y12 selection initially and at discharge by applying an eligibility-assessing algorithm based on P2Y12 inhibitors' contraindications/specific warnings and precautions. \n RESULTS Appropriate, less preferable and inappropriate P2Y12 inhibitor selections were made initially in 45.8%, 47.2% and 6.6% and at discharge in 64.1%, 29.2% and 6.6% of patients, respectively. The selection of clopidogrel was most commonly less preferable, both initially (69.7%) and at discharge (75.6%). Appropriate selection of newer agents was high initially (79.2%-82.8%), with further increase as selection at discharge (89.4%-89.8%). Inappropriate selection of the newer agents was 17.2%-20.8% initially, decreasing to 10.2%-10.6% at discharge. Conditions and co-medications related to increased bleeding risk, presentation with ST elevation myocardial infarction and the absence of reperfusion within the first 24h were the most powerful predictors of appropriate P2Y12 selection initially, whereas age ≥75 years, conditions and co-medications related to increased bleeding risk and regional trends mostly affected appropriate P2Y12 selection at discharge. \n CONCLUSIONS In GRAPE, adherence with the recently released guidelines on oral antiplatelet therapy was satisfactory. Clopidogrel was most commonly used as a less preferable selection, while prasugrel or ticagrelor selection was mostly appropriate. Certain factors may predict initial and at discharge guideline implementation. Clinical Trial Registration-clinicaltrials.gov Identifier: NCT01774955 http://clinicaltrials.gov/.", "title": "Implementation of contemporary oral antiplatelet treatment guidelines in patients with acute coronary syndrome undergoing percutaneous coronary intervention: a report from the GReek AntiPlatelet rEgistry (GRAPE)." }, { "docid": "32001951", "text": "Treatment of the cultured human breast-cancer cells BC-M1 with dexamethasone induced a placental-type alkaline phosphatase (ALP). Both the ALP activity and the mRNA level in the cells were increased. The induction of ALP activity by dexamethasone was time- and dose-dependent. The accumulation of ALP mRNA was inhibited by both actinomycin D and cycloheximide, indicating that its induction is a complex event and may involve other regulatory proteins. Retinoic acid showed opposing effects with dexamethasone on the expression of alkaline phosphatase. Retinoic acid (RA) and phorbol 12-myristate 13-acetate also substantially reduced the dexamethasone-induced expression of ALP. Studies on thermostability and sensitivity to various amino acid inhibitors indicated that the BC-M1 ALP is most similar to the placental form. Northern hybridization analysis also revealed that ALP mRNA transcripts in BC-M1 and term placenta are similar in size and are distinct from that of the placental-like mRNA transcript in choriocarcinoma cells. Analysis of the degradation of BC-M1 ALP mRNA showed a similar half-life of 27 h in the untreated and in dexamethasone- or RA-treated cells. These findings demonstrated that the induction of ALP in BC-M1 cells by dexamethasone is mainly due to the increase in the transcription of the ALP gene.", "title": "Regulation of the expression of alkaline phosphatase in a human breast-cancer cell line." }, { "docid": "6158879", "text": "BACKGROUND Patients with diabetes mellitus (DM) are at high risk for recurrent cardiovascular events after acute coronary syndromes, in part because of increased platelet reactivity. The Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction 38 (TRITON-TIMI 38) showed an overall reduction in ischemic events with more intensive antiplatelet therapy with prasugrel than with clopidogrel but with more bleeding. We compared prasugrel with clopidogrel among subjects with DM in TRITON-TIMI 38. \n METHODS AND RESULTS We classified 13 608 subjects on the basis of preexisting history of DM and further according to insulin use. Prespecified analyses of the primary (cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke) and key secondary end points, including net clinical benefit (death, nonfatal myocardial infarction, nonfatal stroke, and nonfatal TIMI major bleeding) were compared by use of the log-rank test. We found that 3146 subjects had a preexisting history of DM, including 776 receiving insulin. The primary end point was reduced significantly with prasugrel among subjects without DM (9.2% versus 10.6%; hazard ratio [HR], 0.86; P=0.02) and with DM (12.2% versus 17.0%; HR, 0.70; P<0.001, P(interaction)=0.09). A benefit for prasugrel was observed among DM subjects on insulin (14.3% versus 22.2%; HR, 0.63; P=0.009) and those not on insulin (11.5% versus 15.3%; HR, 0.74; P=0.009). Myocardial infarction was reduced with prasugrel by 18% among subjects without DM (7.2% versus 8.7%; HR, 0.82; P=0.006) and by 40% among subjects with DM (8.2% versus 13.2%; HR, 0.60; P<0.001, P(interaction)=0.02). Although TIMI major hemorrhage was increased among subjects without DM on prasugrel (1.6% versus 2.4%; HR, 1.43; P=0.02), the rates were similar among subjects with DM for clopidogrel and prasugrel (2.6% versus 2.5%; HR, 1.06; P=0.81, P(interaction)=0.29). Net clinical benefit with prasugrel was greater for subjects with DM (14.6% versus 19.2%; HR, 0.74; P=0.001) than for subjects without DM (11.5% versus 12.3%; HR, 0.92; P=0.16, P(interaction)=0.05). \n CONCLUSIONS Subjects with DM tended to have a greater reduction in ischemic events without an observed increase in TIMI major bleeding and therefore a greater net treatment benefit with prasugrel compared with clopidogrel. These data demonstrate that the more intensive oral antiplatelet therapy provided with prasugrel is of particular benefit to patients with DM.", "title": "Greater clinical benefit of more intensive oral antiplatelet therapy with prasugrel in patients with diabetes mellitus in the trial to assess improvement in therapeutic outcomes by optimizing platelet inhibition with prasugrel-Thrombolysis in Myocardial Infarction 38." }, { "docid": "14252892", "text": "Osteonecrosis is a severe glucocorticoid-induced complication of acute lymphoblastic leukemia treatment. We prospectively screened children (n = 364) with magnetic resonance imaging of hips and knees, regardless of symptoms; the cumulative incidence of any (grade 1-4) versus symptomatic (grade 2-4) osteonecrosis was 71.8% versus 17.6%, respectively. We investigated whether age, race, sex, acute lymphoblastic leukemia treatment arm, body mass, serum lipids, albumin and cortisol levels, dexamethasone pharmacokinetics, and genome-wide germline genetic polymorphisms were associated with symptomatic osteonecrosis. Age more than 10 years (odds ratio, = 4.85; 95% confidence interval, 2.5-9.2; P = .00001) and more intensive treatment (odds ratio = 2.5; 95% confidence interval, 1.2-4.9; P = .011) were risk factors and included as covariates in all analyses. Lower albumin (P = .05) and elevated cholesterol (P = .02) associated with symptomatic osteonecrosis, and severe (grade 3 or 4) osteonecrosis was linked to poor dexamethasone clearance (P = .0005). Adjusting for clinical features, polymorphisms of ACP1 (eg, rs12714403, P = 1.9 × 10(-6), odds ratio = 5.6; 95% confidence interval, 2.7-11.3), which regulates lipid levels and osteoblast differentiation, were associated with risk of osteonecrosis as well as with lower albumin and higher cholesterol. Overall, older age, lower albumin, higher lipid levels, and dexamethasone exposure were associated with osteonecrosis and may be linked by inherited genomic variation.", "title": "Pharmacokinetic, pharmacodynamic, and pharmacogenetic determinants of osteonecrosis in children with acute lymphoblastic leukemia." }, { "docid": "6083952", "text": "1. Incubation of LMCAT fibroblast cells with antidepressants potentiates glucocorticoid receptor (GR)-mediated gene transcription in the presence of dexamethasone and cortisol, but not of corticosterone. We have shown that antidepressants do so by inhibiting the LMCAT cell membrane steroid transporter (which is virtually identical to the multidrug resistance P-glycoprotein) and thus by increasing dexamethasone or cortisol intracellular concentrations. However, previous experiments with the antidepressant fluoxetine in the presence of dexamethasone have produced negative results (Pariante et al. (2001). Br. J. Pharmacol., 134, 1335-1343). 2. We have since re-examined the effects of fluoxetine on GR-mediated gene transcription in the presence of dexamethasone. Moreover, we have examined the effects of fluoxetine on GR-mediated gene transcription in the presence of cortisol and corticosterone, and on the intracellular accumulation of radioactive cortisol and corticosterone. Finally, we have examined the effects of fluoxetine on inhibition of P-glycoprotein activity in Caco-2 cells. 3. We now find that fluoxetine (1-10 micro M) enhances GR-mediated gene transcription in the presence of dexamethasone and cortisol (+140-170%), but not of corticosterone, and increases the intracellular accumulation of (3)H-cortisol (+5-15%), but not of (3)H-corticosterone. Moreover, fluoxetine (10 micro M) induces approximately 30% inhibition of PGP activity in Caco-2 cells. 4. Our results show that fluoxetine, like other antidepressants, inhibits membrane steroid transporters.", "title": "Antidepressant fluoxetine enhances glucocorticoid receptor function in vitro by modulating membrane steroid transporters." }, { "docid": "18872233", "text": "IMPORTANCE Bariatric surgery is associated with sustained weight loss and improved physical health status for severely obese individuals. Mental health conditions may be common among patients seeking bariatric surgery; however, the prevalence of these conditions and whether they are associated with postoperative outcomes remains unknown. \n OBJECTIVE To determine the prevalence of mental health conditions among bariatric surgery candidates and recipients, to evaluate the association between preoperative mental health conditions and health outcomes following bariatric surgery, and to evaluate the association between surgery and the clinical course of mental health conditions. \n DATA SOURCES We searched PubMed, MEDLINE on OVID, and PsycINFO for studies published between January 1988 and November 2015. Study quality was assessed using an adapted tool for risk of bias; quality of evidence was rated based on GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. \n FINDINGS We identified 68 publications meeting inclusion criteria: 59 reporting the prevalence of preoperative mental health conditions (65,363 patients) and 27 reporting associations between preoperative mental health conditions and postoperative outcomes (50,182 patients). Among patients seeking and undergoing bariatric surgery, the most common mental health conditions, based on random-effects estimates of prevalence, were depression (19% [95% CI, 14%-25%]) and binge eating disorder (17% [95% CI, 13%-21%]). There was conflicting evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Neither depression nor binge eating disorder was consistently associated with differences in weight outcomes. Bariatric surgery was, however, consistently associated with postoperative decreases in the prevalence of depression (7 studies; 8%-74% decrease) and the severity of depressive symptoms (6 studies; 40%-70% decrease). \n CONCLUSIONS AND RELEVANCE Mental health conditions are common among bariatric surgery patients-in particular, depression and binge eating disorder. There is inconsistent evidence regarding the association between preoperative mental health conditions and postoperative weight loss. Moderate-quality evidence supports an association between bariatric surgery and lower rates of depression postoperatively.", "title": "Mental Health Conditions Among Patients Seeking and Undergoing Bariatric Surgery: A Meta-analysis." }, { "docid": "11968641", "text": "BACKGROUND Circadian clocks control cell cycle factors, and circadian disruption promotes cancer. To address whether enhancing circadian rhythmicity in tumor cells affects cell cycle progression and reduces proliferation, we compared growth and cell cycle events of B16 melanoma cells and tumors with either a functional or dysfunctional clock. \n RESULTS We found that clock genes were suppressed in B16 cells and tumors, but treatments inducing circadian rhythmicity, such as dexamethasone, forskolin and heat shock, triggered rhythmic clock and cell cycle gene expression, which resulted in fewer cells in S phase and more in G1 phase. Accordingly, B16 proliferation in vitro and tumor growth in vivo was slowed down. Similar effects were observed in human colon carcinoma HCT-116 cells. Notably, the effects of dexamethasone were not due to an increase in apoptosis nor to an enhancement of immune cell recruitment to the tumor. Knocking down the essential clock gene Bmal1 in B16 tumors prevented the effects of dexamethasone on tumor growth and cell cycle events. \n CONCLUSIONS Here we demonstrated that the effects of dexamethasone on cell cycle and tumor growth are mediated by the tumor-intrinsic circadian clock. Thus, our work reveals that enhancing circadian clock function might represent a novel strategy to control cancer progression.", "title": "Enhancing circadian clock function in cancer cells inhibits tumor growth" }, { "docid": "25293721", "text": "Placental oxidative stress plays a key role in the pathophysiology of placenta-related disorders, most notably preeclampsia (PE) and intrauterine growth restriction (IUGR). Oxidative stress occurs when accumulation of reactive oxygen species (ROS) damages DNA, proteins and lipids, an outcome that is limited by antioxidant enzymes; mitochondrial uncoupling protein 2 (UCP2) may also limit oxidative stress by reducing ROS production. Here we characterized placental antioxidant defenses during normal gestation and following glucocorticoid-induced IUGR. Placentas were collected on Days 16 and 22 of normal rat pregnancy (term = Day 23) and at Day 22 after dexamethasone treatment from Day 13. Expression of several genes encoding antioxidant enzymes (Sod1, Sod2, Sod3, Cat, Gpx3, Txn1, Txnrd1, Txnrd2, and Txnrd3) and Ucp2 was measured by quantitative RT-PCR in the labyrinth (LZ) and junctional zones (JZ) of the placenta. Expression of Sod1 and Ucp2 mRNAs and the activity of xanthine oxidase, a source of ROS, all increased from Days 16 to 22 in both placental zones, whereas Sod2 and Gpx3 increased only in the rapidly growing LZ. In contrast, Sod3 and Txnrd1 expression fell in the LZ over this period, whereas total superoxide dismutase activity remained stable. Dexamethasone treatment reduced fetal-placental growth and LZ expression of Ucp2 but increased JZ expression of Txn1. Indices of placental oxidative damage (TBARS, F2-isoprostanes, and 8-OHdG) did not change with gestational age or dexamethasone, indicative of adequate antioxidant protection. Overall, our data suggest that the rat placenta is protected from oxidative stress by the dynamic zone- and stage-dependent expression of antioxidant defense genes.", "title": "Antioxidant Defenses in the Rat Placenta in Late Gestation: Increased Labyrinthine Expression of Superoxide Dismutases, Glutathione Peroxidase 3, and Uncoupling Protein 21" }, { "docid": "40156901", "text": "BACKGROUND Acute kidney injury (AKI) after cardiac surgery is associated with increased morbidity and mortality. \n METHODS We assessed whether statin treatment is associated with a lower incidence of postoperative AKI in 2,104 consecutive patients who underwent coronary artery bypass graft or valve surgery at the Minneapolis Veterans Administration Medical Center. Acute kidney injury was defined as absolute increase greater than 0.3 mg/dL or relative increase greater than 50% in serum creatinine from baseline, within 48 hours after surgery or requiring postoperative hemodialysis per AKI network. Propensity scores were utilized to adjust for the differences between the statin and the no-statin treatment groups. All statins were converted to equivalent-dose simvastatin and divided at the median to construct high-dose (≥40 mg) and low-dose (<40 mg) statin groups. \n RESULTS Of the 2,104 patients, 1,435 (68%) were taking statins (638 high-dose) and 495 (24%) developed AKI (25% high-dose vs 40% low-dose vs 35% no-statin; p = 0.014). Estimated preoperative glomerular filtration rate (p = 0.003), diabetes mellitus (p=0.02), valve surgery with or without coronary artery bypass graft (p = 0.024), cardiopulmonary bypass time (p = 0.001), and intraaortic balloon pump (p = 0.055) were independent predictors of AKI. After propensity adjustment statin treatment was not associated with postoperative AKI (odds ratio 0.79; 95% confidence interval 0.59 to 1.06; p = 0.11 for high-dose v. no-statin). After full adjustment for all independent predictors of AKI, the results did not change. Statins also had no effect on the incidence of postoperative hemodialysis (0.8% high-dose vs 1.9% low-dose vs 1% no-statin; p = 0.15). \n CONCLUSIONS Statin treatment is not associated with a lower incidence of AKI after cardiac surgery.", "title": "Dose-dependent effect of statins on the incidence of acute kidney injury after cardiac surgery." }, { "docid": "19308127", "text": "BACKGROUND P2Y12 inhibitor switching has appeared in clinical practice as a consequence of prasugrel and ticagrelor availability, apart from clopidogrel, for use in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). \n METHODS In the context of the GReek AntiPlatelet REgistry (GRAPE) we assessed the prevalence, predictive factors and short-term outcome of in-hospital P2Y12 inhibitor switching in 1794 ACS patients undergoing PCI. \n RESULTS Switching occurred in 636 (35.5%) patients of which in the form of clopidogrel to a novel agent, novel agent to clopidogrel and between prasugrel and ticagrelor in 574 (90.4%), 34 (5.3%) and 27 (4.3%) patients, respectively. Presentation to non PCI-capable hospital, bivalirudin use, age ≥75 years (inverse predictor), and regional trends emerged as predictive factors of switching to a novel agent. At combined in-hospital and one-month follow-up, propensity matched pairs analysis showed no differences in major adverse cardiovascular (MACE) or bleeding events between switching from clopidogrel to a novel agent vs novel agent constant administration. More Bleeding Academic Research Consortium type 1, type 2 and any type events and fewer MACE were seen when switching from clopidogrel to a novel agent vs only clopidogrel administration (23.7%, 3.8%, 30.6%, 1.2% vs 8.9%, 1.2%, 12.0%, 3.8% with P < .001, P = .03, P < .001 and P = .03 respectively). \n CONCLUSIONS In a real-life experience with contemporary antiplatelet treatment in ACS patients undergoing PCI, in-hospital switching represents common clinical practice. Clinical factors and regional practice differences seem to affect this strategy's choice, while switching to a novel agent may be associated with higher risk of bleeding.", "title": "In-hospital switching of oral P2Y12 inhibitor treatment in patients with acute coronary syndrome undergoing percutaneous coronary intervention: prevalence, predictors and short-term outcome." }, { "docid": "20887554", "text": "BACKGROUND C-reactive protein (CRP) is a known risk factor for cardiovascular events in the healthy population and in patients with coronary artery disease. High CRP levels before cardiac surgery are associated with worse short-term outcome, but its role after discharge home remains unknown. The study objective was to evaluate the effect of CRP on short-term and mid-term outcome after cardiac surgery. \n METHODS From August 2000 to May 2004, values for preoperative CRP were available for 597 unselected patients undergoing cardiac operations. CRP was used to divide this cohort in two groups: a low inflammatory status (LHS) group of 354 patients with CRP of less than 0.5 mg/dL, and a high inflammatory status (HIS) group of 243 patients with a CRP of 0.5 mg/dL or more. Follow-up lasted a maximum of 3 years (median, 1.8 +/- 1.5 years) and was 92.6% complete. \n RESULTS In-hospital mortality was 8.2% in the HIS group and 3.4% in the LIS group (odds ratio [OR], 2.61; p = 0.02). Incidence of postoperative infections was 16.5% in the HIS group and 5.1% in the LIS group (OR, 3.25; p = 0.0001). Sternal wound infections were also more frequent in the HIS group (10.7% versus 2.8%; OR, 3.43; p = 0.002). During follow-up, the HIS group had worse survival (88.5% +/- 2.9% versus 91.9% +/- 2.5%; OR, 1.93; p = 0.05) and a higher need of hospitalization for cardiac-related causes (73.6% +/- 6% versus 86.5% +/- 3.2%; OR, 1.82; p = 0.05). \n CONCLUSIONS Patients undergoing cardiac surgery with a CRP level of 0.5 mg/dL or more are exposed to a higher risk of in-hospital mortality and postoperative infections. Despite surgical correction of cardiac disease, a high preoperative CRP value is an independent risk factor for mid-term survival and hospitalization for cardiac causes.", "title": "Preoperative C-reactive protein predicts mid-term outcome after cardiac surgery." } ]

[ { "docid": "7098463", "text": "CONTEXT Observational studies suggest that surgically induced loss of weight may be effective therapy for type 2 diabetes. \n OBJECTIVE To determine if surgically induced weight loss results in better glycemic control and less need for diabetes medications than conventional approaches to weight loss and diabetes control. \n DESIGN, SETTING, AND PARTICIPANTS Unblinded randomized controlled trial conducted from December 2002 through December 2006 at the University Obesity Research Center in Australia, with general community recruitment to established treatment programs. Participants were 60 obese patients (BMI >30 and <40) with recently diagnosed (<2 years) type 2 diabetes. \n INTERVENTIONS Conventional diabetes therapy with a focus on weight loss by lifestyle change vs laparoscopic adjustable gastric banding with conventional diabetes care. \n MAIN OUTCOME MEASURES Remission of type 2 diabetes (fasting glucose level <126 mg/dL [7.0 mmol/L] and glycated hemoglobin [HbA1c] value <6.2% while taking no glycemic therapy). Secondary measures included weight and components of the metabolic syndrome. Analysis was by intention-to-treat. \n RESULTS Of the 60 patients enrolled, 55 (92%) completed the 2-year follow-up. Remission of type 2 diabetes was achieved by 22 (73%) in the surgical group and 4 (13%) in the conventional-therapy group. Relative risk of remission for the surgical group was 5.5 (95% confidence interval, 2.2-14.0). Surgical and conventional-therapy groups lost a mean (SD) of 20.7% (8.6%) and 1.7% (5.2%) of weight, respectively, at 2 years (P < .001). Remission of type 2 diabetes was related to weight loss (R2 = 0.46, P < .001) and lower baseline HbA1c levels (combined R2 = 0.52, P < .001). There were no serious complications in either group. \n CONCLUSIONS Participants randomized to surgical therapy were more likely to achieve remission of type 2 diabetes through greater weight loss. These results need to be confirmed in a larger, more diverse population and have long-term efficacy assessed. \n TRIAL REGISTRATION actr.org Identifier: ACTRN012605000159651.", "title": "Adjustable gastric banding and conventional therapy for type 2 diabetes: a randomized controlled trial." } ]

[ { "docid": "5824985", "text": "BACKGROUND Bariatric surgery is becoming a more widespread treatment for obesity. Comprehensive evidence of the long-term effects of contemporary surgery on a broad range of clinical outcomes in large populations treated in routine clinical practice is lacking. The objective of this study was to measure the association between bariatric surgery, weight, body mass index, and obesity-related co-morbidities. \n METHODS AND FINDINGS This was an observational retrospective cohort study using data from the United Kingdom Clinical Practice Research Datalink. All 3,882 patients registered in the database and with bariatric surgery on or before 31 December 2014 were included and matched by propensity score to 3,882 obese patients without surgery. The main outcome measures were change in weight and body mass index over 4 y; incident diagnoses of type 2 diabetes mellitus (T2DM), hypertension, angina, myocardial infarction (MI), stroke, fractures, obstructive sleep apnoea, and cancer; mortality; and resolution of hypertension and T2DM. Weight measures were available for 3,847 patients between 1 and 4 mo, 2,884 patients between 5 and 12 mo, and 2,258 patients between 13 and 48 mo post-procedure. Bariatric surgery patients exhibited rapid weight loss for the first four postoperative months, at a rate of 4.98 kg/mo (95% CI 4.88-5.08). Slower weight loss was sustained to the end of 4 y. Gastric bypass (6.56 kg/mo) and sleeve gastrectomy (6.29 kg/mo) were associated with greater initial weight reduction than gastric banding (2.77 kg/mo). Protective hazard ratios (HRs) were detected for bariatric surgery for incident T2DM, 0.68 (95% CI 0.55-0.83); hypertension, 0.35 (95% CI 0.27-0.45); angina, 0.59 (95% CI 0.40-0.87);MI, 0.28 (95% CI 0.10-0.74); and obstructive sleep apnoea, 0.55 (95% CI 0.40-0.87). Strong associations were found between bariatric surgery and the resolution of T2DM, with a HR of 9.29 (95% CI 6.84-12.62), and between bariatric surgery and the resolution of hypertension, with a HR of 5.64 (95% CI 2.65-11.99). No association was detected between bariatric surgery and fractures, cancer, or stroke. Effect estimates for mortality found no protective association with bariatric surgery overall, with a HR of 0.97 (95% CI 0.66-1.43). The data used were recorded for the management of patients in primary care and may be subject to inaccuracy, which would tend to lead to underestimates of true relative effect sizes. \n CONCLUSIONS Bariatric surgery as delivered in the UK healthcare system is associated with dramatic weight loss, sustained at least 4 y after surgery. This weight loss is accompanied by substantial improvements in pre-existing T2DM and hypertension, as well as a reduced risk of incident T2DM, hypertension, angina, MI, and obstructive sleep apnoea. Widening the availability of bariatric surgery could lead to substantial health benefits for many people who are morbidly obese.", "title": "Bariatric Surgery in the United Kingdom: A Cohort Study of Weight Loss and Clinical Outcomes in Routine Clinical Care." }, { "docid": "25816994", "text": "BACKGROUND Angiotensin receptor blockers (ARB) and angiotensin converting enzyme (ACE) inhibitors are known to reduce proteinuria. Their combination might be more effective than either treatment alone, but long-term data for comparative changes in renal function are not available. We investigated the renal effects of ramipril (an ACE inhibitor), telmisartan (an ARB), and their combination in patients aged 55 years or older with established atherosclerotic vascular disease or with diabetes with end-organ damage. \n METHODS The trial ran from 2001 to 2007. After a 3-week run-in period, 25 620 participants were randomly assigned to ramipril 10 mg a day (n=8576), telmisartan 80 mg a day (n=8542), or to a combination of both drugs (n=8502; median follow-up was 56 months), and renal function and proteinuria were measured. The primary renal outcome was a composite of dialysis, doubling of serum creatinine, and death. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00153101. \n FINDINGS 784 patients permanently discontinued randomised therapy during the trial because of hypotensive symptoms (406 on combination therapy, 149 on ramipril, and 229 on telmisartan). The number of events for the composite primary outcome was similar for telmisartan (n=1147 [13.4%]) and ramipril (1150 [13.5%]; hazard ratio [HR] 1.00, 95% CI 0.92-1.09), but was increased with combination therapy (1233 [14.5%]; HR 1.09, 1.01-1.18, p=0.037). The secondary renal outcome, dialysis or doubling of serum creatinine, was similar with telmisartan (189 [2.21%]) and ramipril (174 [2.03%]; HR 1.09, 0.89-1.34) and more frequent with combination therapy (212 [2.49%]: HR 1.24, 1.01-1.51, p=0.038). Estimated glomerular filtration rate (eGFR) declined least with ramipril compared with telmisartan (-2.82 [SD 17.2] mL/min/1.73 m(2)vs -4.12 [17.4], p<0.0001) or combination therapy (-6.11 [17.9], p<0.0001). The increase in urinary albumin excretion was less with telmisartan (p=0.004) or with combination therapy (p=0.001) than with ramipril. \n INTERPRETATION In people at high vascular risk, telmisartan's effects on major renal outcomes are similar to ramipril. Although combination therapy reduces proteinuria to a greater extent than monotherapy, overall it worsens major renal outcomes.", "title": "Renal outcomes with telmisartan, ramipril, or both, in people at high vascular risk (the ONTARGET study): a multicentre, randomised, double-blind, controlled trial." }, { "docid": "32850528", "text": "OBJECTIVE To evaluate serum amylase and lipase levels and the rate of acute pancreatitis in patients with type 2 diabetes and high cardiovascular risk randomized to liraglutide or placebo and observed for 3.5-5.0 years. RESEARCH DESIGN AND METHODS A total of 9,340 patients with type 2 diabetes were randomized to either liraglutide or placebo (median observation time 3.84 years). Fasting serum lipase and amylase were monitored. Acute pancreatitis was adjudicated in a blinded manner. \n RESULTS Compared with the placebo group, liraglutide-treated patients had increases in serum lipase and amylase of 28.0% and 7.0%, respectively. Levels were increased at 6 months and then remained stable. During the study, 18 (0.4% [1.1 events/1,000 patient-years of observation] [PYO]) liraglutide-treated and 23 (0.5% [1.7 events/1,000 PYO]) placebo patients had acute pancreatitis confirmed by adjudication. Most acute pancreatitis cases occurred ≥12 months after randomization. Liraglutide-treated patients with prior history of pancreatitis (n = 147) were not more likely to develop acute pancreatitis than similar patients in the placebo group (n = 120). Elevations of amylase and lipase levels did not predict future risk of acute pancreatitis (positive predictive value <1.0%) in patients treated with liraglutide. \n CONCLUSIONS In a population with type 2 diabetes at high cardiovascular risk, there were numerically fewer events of acute pancreatitis among liraglutide-treated patients (regardless of previous history of pancreatitis) compared with the placebo group. Liraglutide was associated with increases in serum lipase and amylase, which were not predictive of an event of subsequent acute pancreatitis.", "title": "Amylase, Lipase, and Acute Pancreatitis in People With Type 2 Diabetes Treated With Liraglutide: Results From the LEADER Randomized Trial." }, { "docid": "16390264", "text": "OBJECTIVES To determine the extent to which type of hospital admission (emergency compared with elective) and surgical procedure varied by socioeconomic circumstances, age, sex, and year of admission for colorectal, breast, and lung cancer. \n DESIGN Repeated cross sectional study with data from individual patients, 1 April 1999 to 31 March 2006. \n SETTING Hospital episode statistics (HES) dataset. \n PARTICIPANTS 564 821 patients aged 50 and over admitted with a diagnosis of colorectal, breast, or lung cancer. \n MAIN OUTCOME MEASURES Proportion of patients admitted as emergencies, and the proportion receiving the recommended surgical treatment. \n RESULTS Patients from deprived areas, older people, and women were more likely to be admitted as emergencies. For example, the adjusted odds ratio for patients with breast cancer in the least compared with most deprived fifth of deprivation was 0.63 (95% confidence interval 0.60 to 0.66) and the adjusted odds ratio for patients with lung cancer aged 80-89 compared with those aged 50-59 was 3.13 (2.93 to 3.34). There were some improvements in disparities between age groups but not for patients living in deprived areas over time. Patients from deprived areas were less likely to receive preferred procedures for rectal, breast, and lung cancer. These findings did not improve with time. For example, 67.4% (3529/5237) of patients in the most deprived fifth of deprivation had anterior resection for rectal cancer compared with 75.5% (4497/5959) of patients in the least deprived fifth (1.34, 1.22 to 1.47). Over half (54.0%, 11 256/20 849) of patients in the most deprived fifth of deprivation had breast conserving surgery compared with 63.7% (18 445/28 960) of patients in the least deprived fifth (1.21, 1.16 to 1.26). Men were less likely than women to undergo anterior resection and lung cancer resection and older people were less likely to receive breast conserving surgery and lung cancer resection. For example, the adjusted odds ratio for lung cancer patients aged 80-89 compared with those aged 50-59 was 0.52 (0.46 to 0.59). Conclusions Despite the implementation of the NHS Cancer Plan, social factors still strongly influence access to and the provision of care.", "title": "Social variations in access to hospital care for patients with colorectal, breast, and lung cancer between 1999 and 2006: retrospective analysis of hospital episode statistics" }, { "docid": "750781", "text": "BACKGROUND Few studies have compared long-term status of bypass grafts between patients with and without diabetes, and uncertainty exists as to whether diabetes independently predicts poor clinical outcome after CABG. \n METHODS AND RESULTS Among 1526 patients in BARI who underwent CABG as initial revascularization, 99 of 292 (34%) with treated diabetes mellitus (TDM) (those on insulin or oral hypoglycemic agents) and 469 of 1234 (38%) without TDM had follow-up angiography. Angiograms with the longest interval from initial surgery and before any percutaneous graft intervention (mean 3.9 years) were reviewed. An average of 3.0 grafts were placed at initial CABG for patients with TDM (n=297; internal mammary artery [IMA], 33%) and 2.9 grafts for patients without TDM (n=1347; IMA, 34%). Patients with TDM were more likely than those without to have small (<1.5 mm) grafted distal vessels (29% versus 22%) and vessels of poor quality (9% versus 6%). On follow-up angiography, 89% of IMA grafts were free of stenoses > or =50% among patients with TDM versus 85% among patients without TDM (P=0.23). For vein grafts, the corresponding percentages were 71% versus 75% (P=0.40). After statistical adjustment, TDM was unrelated to having a graft stenosis > or =50% (adjusted odds ratio, 0.87; 95% CI, 0.58 to 1.32). \n CONCLUSIONS Despite diabetic patients' having smaller distal vessels and vessels judged to be of poorer quality, diabetes does not appear to adversely affect patency of IMA or vein grafts over an average of 4-year follow-up. Previously observed differences in survival between CABG-treated patients with and without diabetes may be largely a result of differential risk of mortality from noncardiac causes.", "title": "Coronary bypass graft patency in patients with diabetes in the Bypass Angioplasty Revascularization Investigation (BARI)." }, { "docid": "24921368", "text": "Impaired awareness of hypoglycaemia (IAH) is an acquired complication of insulin therapy, which affects people with type 1 and insulin-treated type 2 diabetes mellitus, whereby the ability to perceive the onset of hypoglycaemia becomes diminished or absent. Deficiencies of the counter-regulatory hormonal responses to hypoglycaemia usually co-exist. The development of IAH and counter-regulatory failure greatly increases the risk of severe hypoglycaemia. Scoring systems have been developed that can be used in the clinical setting and assist with identification of this group of individuals at risk of severe hypoglycaemia. The mainstay of treatment of IAH is the scrupulous avoidance of hypoglycaemia.", "title": "Impaired awareness of hypoglycaemia: a review." }, { "docid": "23639838", "text": "Brain metastases occur in up to 40% of patients with cancer. Their management has been revolutionized in the last decade by three developments: improved imaging and detection of metastases, better treatment of systemic disease with the result that metastases occur more often; and improved surgical techniques including image-guided surgery to treat metastatic lesions. Class 1 data suggest that surgery is a better treatment for metastases than whole brain radiation. Other data suggest that metastases even in eloquent cortex can be removed safely. The complication rate is low and the recurrence rate is less than 10%. In general, indications for surgery include a mass with an unknown primary; a symptomatic mass including one in eloquent areas; a mass with considerable edema requiring high dose steroids; a mass greater than 3 cm; or patient preference when radiosurgery may also be an option. The question of radiosurgery or whole brain radiation as adjunct to surgical removal requires further evaluation.", "title": "Surgical Resection for Patients with Solid Brain Metastases: Current Status" }, { "docid": "374902", "text": "BACKGROUND Roughly 3 million people worldwide were receiving antiretroviral therapy (ART) at the end of 2007, but an estimated 6.7 million were still in need of treatment and a further 2.7 million became infected with HIV in 2007. Prevention efforts might reduce HIV incidence but are unlikely to eliminate this disease. We investigated a theoretical strategy of universal voluntary HIV testing and immediate treatment with ART, and examined the conditions under which the HIV epidemic could be driven towards elimination. \n METHODS We used mathematical models to explore the effect on the case reproduction number (stochastic model) and long-term dynamics of the HIV epidemic (deterministic transmission model) of testing all people in our test-case community (aged 15 years and older) for HIV every year and starting people on ART immediately after they are diagnosed HIV positive. We used data from South Africa as the test case for a generalised epidemic, and assumed that all HIV transmission was heterosexual. \n FINDINGS The studied strategy could greatly accelerate the transition from the present endemic phase, in which most adults living with HIV are not receiving ART, to an elimination phase, in which most are on ART, within 5 years. It could reduce HIV incidence and mortality to less than one case per 1000 people per year by 2016, or within 10 years of full implementation of the strategy, and reduce the prevalence of HIV to less than 1% within 50 years. We estimate that in 2032, the yearly cost of the present strategy and the theoretical strategy would both be US$1.7 billion; however, after this time, the cost of the present strategy would continue to increase whereas that of the theoretical strategy would decrease. \n INTERPRETATION Universal voluntary HIV testing and immediate ART, combined with present prevention approaches, could have a major effect on severe generalised HIV/AIDS epidemics. This approach merits further mathematical modelling, research, and broad consultation.", "title": "Universal voluntary HIV testing with immediate antiretroviral therapy as a strategy for elimination of HIV transmission: a mathematical model." }, { "docid": "5262240", "text": "AIMS To investigate the pattern of changes in HbA1c in people with Type 1 diabetes managed by long-term Continuous subcutaneous insulin infusion. \n METHODS We studied HbA1c changes using computerized clinic records in 35 adult people with Type 1 diabetes and an elevated HbA1c (≥ 64 mmol/mol, 8.0%) on multiple daily insulin injections, who were then switched to continuous subcutaneous insulin infusion for at least 5 years. \n RESULTS We identified three subgroups with similar baseline HbA1c but different long-term responses to pump therapy: group A--those with improvement followed by deterioration (57%); group B--those with improvement that was sustained throughout the 5 years (31%); and group C-those where HbA1c did not change significantly from baseline (12%). The patients in group C had a higher BMI: 31.0 ± 5.2 vs. 25.9 ± 3.3 vs. 25.2 ± 3.1 kg/m² (group C vs. group A and group B; P = 0.02). \n CONCLUSIONS Improved glycaemic control with continuous subcutaneous insulin infusion was maintained over 5 years by 88% of people with Type 1 diabetes in this study, but there were variations in the long-term efficacy, with some people improving and worsening, others maintaining strict control and a few subcutaneous insulin infusion 'non-responders'.", "title": "Variations in the quality and sustainability of long-term glycaemic control with continuous subcutaneous insulin infusion." }, { "docid": "3190689", "text": "BACKGROUND Laparoscopic adhesiolysis for chronic abdominal pain is controversial and is not evidence based. We aimed to test our hypothesis that laparoscopic adhesiolysis leads to substantial pain relief and improvement in quality of life in patients with adhesions and chronic abdominal pain. \n METHODS Patients had diagnostic laparoscopy for chronic abdominal pain attributed to adhesions; other causes for their pain had been excluded. If adhesions were confirmed during diagnostic laparoscopy, patients were randomly assigned either to laparoscopic adhesiolysis or no treatment. Treatment allocation was concealed from patients, and assessors were unaware of patients' treatment and outcome. Pain was assessed for 1 year by visual analogue score (VAS) score (scale 0-100), pain change score, use of analgesics, and quality of life score. Analysis was by intention to treat. \n FINDINGS Of 116 patients enrolled for diagnostic laparoscopy, 100 were randomly allocated either laparoscopic adhesiolysis (52) or no treatment (48). Both groups reported substantial pain relief and a significantly improved quality of life, but there was no difference between the groups (mean change from baseline of VAS score at 12 months: difference 3 points, p=0.53; 95% CI -7 to 13). \n INTERPRETATION Although laparoscopic adhesiolysis relieves chronic abdominal pain, it is not more beneficial than diagnostic laparoscopy alone. Therefore, laparoscopic adhesiolysis cannot be recommended as a treatment for adhesions in patients with chronic abdominal pain.", "title": "Laparoscopic adhesiolysis in patients with chronic abdominal pain: a blinded randomised controlled multi-centre trial." }, { "docid": "10300000", "text": "The results of a survey of 769 patients attending the St. James's University Fertility Control Clinic, England, for abortion services showed that patients seeing general practitioners were less knowledgeable than those attending specialist clinics. There was a demonstrated need for counseling on pill and condom use and protection against sexually transmitted diseases. Knowledge of postcoital methods was also found to be lacking. The survey was conducted between April 1, 1991, and January 31, 1992. Respondents included minorities such as Afro-Caribbean (8%) and Asian (9%). 307 of the cases were using a less effective form of contraception at the time of conception, usually a change from the pill to condoms. Of the 171 people reporting failure of contraception, 93 noted a split or leaking condom; 13, a condom falling off during intercourse; 32, inconsistent use of condoms;l 32, forgetting to take contraceptive pills or using antibiotics with the pill; and 1, a late injection of medroxyprogesterone acetate. 45 of the 309 people who had conceived while using condoms recognized a potential condom failure, and only 20 attempted any emergency contraceptive method such as the postcoital pill. Only 30% of the 171 patients with recognized condom failure and 12% of the 210 who had not used any contraception had adequate knowledge of the existence, timing, and source of postcoital pills; i.e., 20% of 381. Only 2% of the 171 nd 2% of the 381 patients, had knowledge of postcoital insertion of an intrauterine contraceptive device. Given the choice between and unplanned pregnancy and postcoital contraceptive, most (718 out of 769) preferred using postcoital contraception. Contraceptive information was given to 501 by a general practitioner, to 102 by a community family planning clinic, and 163 had no medical advice. There was a range of knowledge of postcoital contraceptive methods. Knowledge of how to deal with forgotten pills, severe vomiting, severe diarrhea, and concurrent antibiotic treatment among the 422 patients who had ever used the combined pill also was variable. 19% of the 372 patients treated by general practitioners knew 4 correct answers, but 50% of the 50 patients in community family planning clinics answered correctly 4 times. Differences could not be explained by other demographic characteristics.", "title": "Knowledge and use of secondary contraception among patients requesting termination of pregnancy." }, { "docid": "12584053", "text": "OBJECTIVE To measure whether the benefits of a single education and self management structured programme for people with newly diagnosed type 2 diabetes mellitus are sustained at three years. \n DESIGN Three year follow-up of a multicentre cluster randomised controlled trial in primary care, with randomisation at practice level. \n SETTING 207 general practices in 13 primary care sites in the United Kingdom. \n PARTICIPANTS 731 of the 824 participants included in the original trial were eligible for follow-up. Biomedical data were collected on 604 (82.6%) and questionnaire data on 513 (70.1%) participants. \n INTERVENTION A structured group education programme for six hours delivered in the community by two trained healthcare professional educators compared with usual care. \n MAIN OUTCOME MEASURES The primary outcome was glycated haemoglobin (HbA(1c)) levels. The secondary outcomes were blood pressure, weight, blood lipid levels, smoking status, physical activity, quality of life, beliefs about illness, depression, emotional impact of diabetes, and drug use at three years. \n RESULTS HbA(1c) levels at three years had decreased in both groups. After adjusting for baseline and cluster the difference was not significant (difference -0.02, 95% confidence interval -0.22 to 0.17). The groups did not differ for the other biomedical and lifestyle outcomes and drug use. The significant benefits in the intervention group across four out of five health beliefs seen at 12 months were sustained at three years (P<0.01). Depression scores and quality of life did not differ at three years. \n CONCLUSION A single programme for people with newly diagnosed type 2 diabetes mellitus showed no difference in biomedical or lifestyle outcomes at three years although there were sustained improvements in some illness beliefs. \n TRIAL REGISTRATION Current Controlled Trials ISRCTN17844016.", "title": "Effectiveness of a diabetes education and self management programme (DESMOND) for people with newly diagnosed type 2 diabetes mellitus: three year follow-up of a cluster randomised controlled trial in primary care" }, { "docid": "6751418", "text": "UNLABELLED In patients with a large, multinodular goiter (> 100 g), radiation absorbed doses in the thyroid, surrounding tissues and remainder of the body were estimated after therapeutic administration of 131I(3.7 MBq or 100 microCi/g of thyroid tissue retained at 24 hr). \n METHODS Thermoluminescent dosimeter (TLD) measurements were performed on 23 patients (12 euthyroid and 1I hyperthyroid; thyroid weight 222 +/- 72 g; 2.1 +/- 0.9 GBq 131I) on the skin over the thyroid, over the submandibular gland and over the parotid gland. Thyroid radioactivity measurements were done daily in 6 euthyroid and 6 hyperthyroid patients (thyroid weight 204 +/- 69 g; 1.9 +/- 0.9 GBq 131I). An iodine biokinetic model and the MIRD methodology were used to estimate absorbed doses in organs. Cancer risks were calculated using ICRP Publication 60. \n RESULTS Cumulated absorbed doses on the skin (TLD measurements) were 4.2 +/- 1.4 Gy (thyroid), 1.2 +/- 0.6 Gy (submandibular) and 0.4 +/- 0.2 Gy (parotid). All these values were significantly correlated with the amount of radioiodine retained in the thyroid at 24 hr (euthyroid versus hyperthyroid not significant). Absorbed doses in the thyroid of 94 +/- 25 Gy for euthyroid and 93 +/- 17 Gy for hyperthyroid patients were calculated (thyroid radioactivity measurements). Extrathyroidal absorbed doses (means of 12 patients) were 0.88 Gy in the urinary bladder, 0.57 Gy in the small intestine, 0.38 Gy in the stomach, and ranged from 0.05 to 0.30 Gy in other organs (euthyroid versus hyperthyroid not significant). A 1.6% life-time risk of development of cancer outside the thyroid gland was calculated. When applied to people of 65 yr and older the estimated risk is approximately 0.5%. \n CONCLUSION These data may help in choosing the treatment regimen for individual patients with a large, multinodular goiter, who have to be treated for hyperthyroidism or compressive problems. In younger patients, surgery may be preferred. However, for elderly patients and patients with cardiopulmonary disease, the advantages of noninvasive radioiodine treatment will outweight the life-time risk of this mode of therapy.", "title": "Dosimetry and risk estimates of radioiodine therapy for large, multinodular goiters." }, { "docid": "43122426", "text": "We studied 201 consecutive patients who received a relatively fixed dose of radioiodine for the treatment of hyperthyroidism between the years 1981-6. Patients with Graves' disease (170) were initially treated with a mean (SE) dose of 369 (10) MBq 131-I with a remission rate of 94% at 6 months and a cumulative relapse rate of 12% at one year and 21% at 5 years. The cumulative incidence of hypothyroidism was 26% at 3 months, 55% at 6 months, 61% at 1 year and 66% at 5 years. Patients with a uninodular goitre (10) were initially treated with a mean (SE) dose of 438 (85) MBq 131-I with a remission rate of 100% at 6 months, without relapse at 1 year but relapsing in 17% at 5 years. The cumulative incidence of hypothyroidism was 26% at 3 months, 30% at 6 months, 40% at 1 year and 40% at 5 years. Patients with a multinodular goitre (21) were initially treated with a mean (SE) dose of 613 (77) MBq 131-I with a remission rate of 79% at 6 months and a cumulative relapse rate of 26% at 1 year and 39% at 5 years. The cumulative incidence of hypothyroidism was 5% at 3 months, 14% at 6 months, 24% at 1 year and 24% at 5 years.", "title": "131-I radioiodine therapy for hyperthyroidism in patients with Graves' disease, uninodular goitre and multinodular goitre." }, { "docid": "44384384", "text": "AIMS While randomized clinical trials have compared clopidogrel with higher potency adenosine diphosphate (ADP) receptor inhibitors among patients with acute myocardial infarction, little is known about the frequency, effectiveness and safety of switching between ADP receptor inhibitors in routine clinical practice. \n METHODS AND RESULTS We studied 11,999 myocardial infarction patients treated with percutaneous coronary intervention at 230 hospitals from April 2010 to October 2012 in the TRANSLATE-ACS study. Multivariable Cox regression was used to compare six-month post-discharge risks of major adverse cardiovascular events (MACE: death, myocardial infarction, stroke, or unplanned revascularization) and Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-defined bleeding between in-hospital ADP receptor inhibitor switching versus continuation of the initially selected therapy. Among 8715 patients treated initially with clopidogrel, 994 (11.4%) were switched to prasugrel or ticagrelor; switching occurred primarily after percutaneous coronary intervention (60.9%) and at the time of hospital discharge (26.7%). Among 3284 patients treated initially with prasugrel or ticagrelor, 448 (13.6%) were switched to clopidogrel; 48.2% of switches occurred after percutaneous coronary intervention and 48.0% at hospital discharge. Switching to prasugrel or ticagrelor was not associated with increased bleeding when compared with continuation on clopidogrel (2.7% vs. 3.3%, adjusted hazard ratio 0.96, 95% confidence interval 0.64-1.42, p=0.82). Switching from prasugrel or ticagrelor to clopidogrel was not associated with increased MACE (8.9% vs. 7.7%, adjusted hazard ratio 1.06, 95% confidence interval 0.75-1.49, p=0.76) when compared with continuation on the higher potency agent. \n CONCLUSIONS In-hospital ADP receptor inhibitor switching occurs in more than one in 10 myocardial infarction patients in contemporary practice. In this observational study, ADP receptor inhibitor switching does not appear to be significantly associated with increased hazard of MACE or bleeding.", "title": "In-hospital switching between adenosine diphosphate receptor inhibitors in patients with acute myocardial infarction treated with percutaneous coronary intervention: Insights into contemporary practice from the TRANSLATE-ACS study." }, { "docid": "58050905", "text": "The World Health Organisation has declared the period 2000 to 2010 the Bone and Joint Decade. This is indeed timely and appropriate. Hundreds of millions of people in the world today are beset with a host of disabilities caused by trauma, ageing and degeneration and other affections of the musculo-skeletal system. With the state of art of orthopaedic surgery and rheumatology, sufferers of bone and joint disabilities have benefited a great deal from advances in pharmacology, newer techniques of imaging, surgery and man-made materials to replace diseased or damaged bone and cartilage. However, man-made materials, being non-living, are subject to wear and tear and loosening in the host bone. As we advance into the Bone and Joint Decade, further improvement in the treatment of bone and joint diseases lies in more basic cartilage and bone research. The Human Genome Project has provided us with a better understanding of disease genes and the possibility of gene manipulation to prevent and treat specific diseases. Cartilage cells culture and transplant are already a reality. Tissue engineering, i.e. growing cells in three-dimensional substrates of collagen or synthetic biodegradable polymers, started in the 1980s, will in future be used to replace damaged bone and cartilage parts with living and bone and cartilaginous tissues, respectively. The first steps have been taken; more research needs to be done. And it is not unreasonable to expect a significant breakthrough in the treatment of bone and joint diseases at the end of this decade. Ann Acad Med Singapore 2002; 31:621-2", "title": "The Bone and Joint Decade 2000-2010." }, { "docid": "22635278", "text": "From April 1986 to September 2000, 122 MRCC patients were treated by monthly intralymphatic injections (containing a mean of 573 IL-2 U and 26 x 10(6) LAK cells) and i.m. administration of IFN and TF; 71 patients also received a 3-day cycle of monthly IL-2 inhalations with a mean of 998 daily U. MRCC cases not treated by immunotherapy (n = 89) represent our historical controls. Adverse clinical side effects related to treatment were negligible. CR (n = 11) and PR (n = 13) were noticed in 24/122 patients. Of 24 responding patients, 17 resumed progression, whereas 7 remain in remission 11-69 months later. The overall median survival of treated patients (28 months) was 3.5-fold higher than the median survival of historical controls (7.5 months), and a Kaplan-Meier curve showed 25% survival 11 years after the beginning of immunotherapy. Apparently, the addition of IL-2 by inhalation improved survival. The present immunotherapy protocol appears to be efficacious, safe, devoid of adverse side effects, far less costly than others and able to offer a good quality of life to MRCC patients; if confirmed in a multicenter trial, it could set the basis for developing low-dose immunomodulatory treatments.", "title": "Immunotherapy of metastatic kidney cancer." }, { "docid": "5687200", "text": "AIMS The aim of this study was to compare the effects of calorie-restricted vegetarian and conventional diabetic diets alone and in combination with exercise on insulin resistance, visceral fat and oxidative stress markers in subjects with Type 2 diabetes. \n METHODS A 24-week, randomized, open, parallel design was used. Seventy-four patients with Type 2 diabetes were randomly assigned to either the experimental group (n = 37), which received a vegetarian diet, or the control group (n = 37), which received a conventional diabetic diet. Both diets were isocaloric, calorie restricted (-500 kcal/day). All meals during the study were provided. The second 12 weeks of the diet were combined with aerobic exercise. Participants were examined at baseline, 12 weeks and 24 weeks. Primary outcomes were: insulin sensitivity measured by hyperinsulinaemic isoglycaemic clamp; volume of visceral and subcutaneous fat measured by magnetic resonance imaging; and oxidative stress measured by thiobarbituric acid reactive substances. Analyses were by intention to treat. \n RESULTS Forty-three per cent of participants in the experimental group and 5% of participants in the control group reduced diabetes medication (P < 0.001). Body weight decreased more in the experimental group than in the control group [-6.2 kg (95% CI -6.6 to -5.3) vs. -3.2 kg (95% CI -3.7 to -2.5); interaction group × time P = 0.001]. An increase in insulin sensitivity was significantly greater in the experimental group than in the control group [30% (95% CI 24.5-39) vs. 20% (95% CI 14-25), P = 0.04]. A reduction in both visceral and subcutaneous fat was greater in the experimental group than in the control group (P = 0.007 and P = 0.02, respectively). Plasma adiponectin increased (P = 0.02) and leptin decreased (P = 0.02) in the experimental group, with no change in the control group. Vitamin C, superoxide dismutase and reduced glutathione increased in the experimental group (P = 0.002, P < 0.001 and P = 0.02, respectively). Differences between groups were greater after the addition of exercise training. Changes in insulin sensitivity and enzymatic oxidative stress markers correlated with changes in visceral fat. \n CONCLUSIONS A calorie-restricted vegetarian diet had greater capacity to improve insulin sensitivity compared with a conventional diabetic diet over 24 weeks. The greater loss of visceral fat and improvements in plasma concentrations of adipokines and oxidative stress markers with this diet may be responsible for the reduction of insulin resistance. The addition of exercise training further augmented the improved outcomes with the vegetarian diet.", "title": "Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes" }, { "docid": "4474874", "text": "BACKGROUND & AIMS Ghrelin is an orexigenic peptide with gastroprokinetic effects. Mice with streptozotocin (STZ)-induced diabetes exhibit hyperphagia, altered gastric emptying, and increased plasma ghrelin levels. We investigated the causative role of ghrelin herein by comparing changes in ghrelin receptor knockout (growth hormone secretagogue receptor [GHS-R](-/-)) and wild-type (GHS-R(+/+)) mice with STZ-induced diabetes. \n METHODS Gastric emptying was measured with the [(13)C]octanoic acid breath test. The messenger RNA (mRNA) expression of neuropeptide Y (NPY), agouti-related peptide (AgRP), and proopiomelanocortin was quantified by real-time reverse-transcription polymerase chain reaction. Neural contractions were elicited by electrical field stimulation in fundic smooth muscle strips. \n RESULTS Diabetes increased plasma ghrelin levels to a similar extent in both genotypes. Hyperphagia was more pronounced in GHS-R(+/+) than in GHS-R(-/-) mice between days 12 and 21. Increases in NPY and AgRP mRNA expression were less pronounced in diabetic GHS-R(-/-) than in GHS-R(+/+) mice from day 15 on, whereas decreases in proopiomelanocortin mRNA levels were similar in both genotypes. Gastric emptying was accelerated to a similar extent in both genotypes, starting on day 16. In fundic smooth muscle strips of diabetic GHS-R(+/+) and GHS-R(-/-) mice, neuronal relaxations were reduced, whereas contractions were increased; this increase was related to an increased affinity of muscarinic and tachykinergic receptors. \n CONCLUSIONS Diabetic hyperphagia is regulated by central mechanisms in which the ghrelin-signaling pathway affects the expression of NPY and AgRP in the hypothalamus. The acceleration of gastric emptying, which is not affected by ghrelin signaling, is not the cause of diabetic hyperphagia and probably involves local contractility changes in the fundus.", "title": "Role of ghrelin in the relationship between hyperphagia and accelerated gastric emptying in diabetic mice." } ]

[ { "docid": "7098463", "text": "CONTEXT Observational studies suggest that surgically induced loss of weight may be effective therapy for type 2 diabetes. \n OBJECTIVE To determine if surgically induced weight loss results in better glycemic control and less need for diabetes medications than conventional approaches to weight loss and diabetes control. \n DESIGN, SETTING, AND PARTICIPANTS Unblinded randomized controlled trial conducted from December 2002 through December 2006 at the University Obesity Research Center in Australia, with general community recruitment to established treatment programs. Participants were 60 obese patients (BMI >30 and <40) with recently diagnosed (<2 years) type 2 diabetes. \n INTERVENTIONS Conventional diabetes therapy with a focus on weight loss by lifestyle change vs laparoscopic adjustable gastric banding with conventional diabetes care. \n MAIN OUTCOME MEASURES Remission of type 2 diabetes (fasting glucose level <126 mg/dL [7.0 mmol/L] and glycated hemoglobin [HbA1c] value <6.2% while taking no glycemic therapy). Secondary measures included weight and components of the metabolic syndrome. Analysis was by intention-to-treat. \n RESULTS Of the 60 patients enrolled, 55 (92%) completed the 2-year follow-up. Remission of type 2 diabetes was achieved by 22 (73%) in the surgical group and 4 (13%) in the conventional-therapy group. Relative risk of remission for the surgical group was 5.5 (95% confidence interval, 2.2-14.0). Surgical and conventional-therapy groups lost a mean (SD) of 20.7% (8.6%) and 1.7% (5.2%) of weight, respectively, at 2 years (P < .001). Remission of type 2 diabetes was related to weight loss (R2 = 0.46, P < .001) and lower baseline HbA1c levels (combined R2 = 0.52, P < .001). There were no serious complications in either group. \n CONCLUSIONS Participants randomized to surgical therapy were more likely to achieve remission of type 2 diabetes through greater weight loss. These results need to be confirmed in a larger, more diverse population and have long-term efficacy assessed. \n TRIAL REGISTRATION actr.org Identifier: ACTRN012605000159651.", "title": "Adjustable gastric banding and conventional therapy for type 2 diabetes: a randomized controlled trial." } ]

[ { "docid": "5824985", "text": "BACKGROUND Bariatric surgery is becoming a more widespread treatment for obesity. Comprehensive evidence of the long-term effects of contemporary surgery on a broad range of clinical outcomes in large populations treated in routine clinical practice is lacking. The objective of this study was to measure the association between bariatric surgery, weight, body mass index, and obesity-related co-morbidities. \n METHODS AND FINDINGS This was an observational retrospective cohort study using data from the United Kingdom Clinical Practice Research Datalink. All 3,882 patients registered in the database and with bariatric surgery on or before 31 December 2014 were included and matched by propensity score to 3,882 obese patients without surgery. The main outcome measures were change in weight and body mass index over 4 y; incident diagnoses of type 2 diabetes mellitus (T2DM), hypertension, angina, myocardial infarction (MI), stroke, fractures, obstructive sleep apnoea, and cancer; mortality; and resolution of hypertension and T2DM. Weight measures were available for 3,847 patients between 1 and 4 mo, 2,884 patients between 5 and 12 mo, and 2,258 patients between 13 and 48 mo post-procedure. Bariatric surgery patients exhibited rapid weight loss for the first four postoperative months, at a rate of 4.98 kg/mo (95% CI 4.88-5.08). Slower weight loss was sustained to the end of 4 y. Gastric bypass (6.56 kg/mo) and sleeve gastrectomy (6.29 kg/mo) were associated with greater initial weight reduction than gastric banding (2.77 kg/mo). Protective hazard ratios (HRs) were detected for bariatric surgery for incident T2DM, 0.68 (95% CI 0.55-0.83); hypertension, 0.35 (95% CI 0.27-0.45); angina, 0.59 (95% CI 0.40-0.87);MI, 0.28 (95% CI 0.10-0.74); and obstructive sleep apnoea, 0.55 (95% CI 0.40-0.87). Strong associations were found between bariatric surgery and the resolution of T2DM, with a HR of 9.29 (95% CI 6.84-12.62), and between bariatric surgery and the resolution of hypertension, with a HR of 5.64 (95% CI 2.65-11.99). No association was detected between bariatric surgery and fractures, cancer, or stroke. Effect estimates for mortality found no protective association with bariatric surgery overall, with a HR of 0.97 (95% CI 0.66-1.43). The data used were recorded for the management of patients in primary care and may be subject to inaccuracy, which would tend to lead to underestimates of true relative effect sizes. \n CONCLUSIONS Bariatric surgery as delivered in the UK healthcare system is associated with dramatic weight loss, sustained at least 4 y after surgery. This weight loss is accompanied by substantial improvements in pre-existing T2DM and hypertension, as well as a reduced risk of incident T2DM, hypertension, angina, MI, and obstructive sleep apnoea. Widening the availability of bariatric surgery could lead to substantial health benefits for many people who are morbidly obese.", "title": "Bariatric Surgery in the United Kingdom: A Cohort Study of Weight Loss and Clinical Outcomes in Routine Clinical Care." }, { "docid": "32850528", "text": "OBJECTIVE To evaluate serum amylase and lipase levels and the rate of acute pancreatitis in patients with type 2 diabetes and high cardiovascular risk randomized to liraglutide or placebo and observed for 3.5-5.0 years. RESEARCH DESIGN AND METHODS A total of 9,340 patients with type 2 diabetes were randomized to either liraglutide or placebo (median observation time 3.84 years). Fasting serum lipase and amylase were monitored. Acute pancreatitis was adjudicated in a blinded manner. \n RESULTS Compared with the placebo group, liraglutide-treated patients had increases in serum lipase and amylase of 28.0% and 7.0%, respectively. Levels were increased at 6 months and then remained stable. During the study, 18 (0.4% [1.1 events/1,000 patient-years of observation] [PYO]) liraglutide-treated and 23 (0.5% [1.7 events/1,000 PYO]) placebo patients had acute pancreatitis confirmed by adjudication. Most acute pancreatitis cases occurred ≥12 months after randomization. Liraglutide-treated patients with prior history of pancreatitis (n = 147) were not more likely to develop acute pancreatitis than similar patients in the placebo group (n = 120). Elevations of amylase and lipase levels did not predict future risk of acute pancreatitis (positive predictive value <1.0%) in patients treated with liraglutide. \n CONCLUSIONS In a population with type 2 diabetes at high cardiovascular risk, there were numerically fewer events of acute pancreatitis among liraglutide-treated patients (regardless of previous history of pancreatitis) compared with the placebo group. Liraglutide was associated with increases in serum lipase and amylase, which were not predictive of an event of subsequent acute pancreatitis.", "title": "Amylase, Lipase, and Acute Pancreatitis in People With Type 2 Diabetes Treated With Liraglutide: Results From the LEADER Randomized Trial." }, { "docid": "25816994", "text": "BACKGROUND Angiotensin receptor blockers (ARB) and angiotensin converting enzyme (ACE) inhibitors are known to reduce proteinuria. Their combination might be more effective than either treatment alone, but long-term data for comparative changes in renal function are not available. We investigated the renal effects of ramipril (an ACE inhibitor), telmisartan (an ARB), and their combination in patients aged 55 years or older with established atherosclerotic vascular disease or with diabetes with end-organ damage. \n METHODS The trial ran from 2001 to 2007. After a 3-week run-in period, 25 620 participants were randomly assigned to ramipril 10 mg a day (n=8576), telmisartan 80 mg a day (n=8542), or to a combination of both drugs (n=8502; median follow-up was 56 months), and renal function and proteinuria were measured. The primary renal outcome was a composite of dialysis, doubling of serum creatinine, and death. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00153101. \n FINDINGS 784 patients permanently discontinued randomised therapy during the trial because of hypotensive symptoms (406 on combination therapy, 149 on ramipril, and 229 on telmisartan). The number of events for the composite primary outcome was similar for telmisartan (n=1147 [13.4%]) and ramipril (1150 [13.5%]; hazard ratio [HR] 1.00, 95% CI 0.92-1.09), but was increased with combination therapy (1233 [14.5%]; HR 1.09, 1.01-1.18, p=0.037). The secondary renal outcome, dialysis or doubling of serum creatinine, was similar with telmisartan (189 [2.21%]) and ramipril (174 [2.03%]; HR 1.09, 0.89-1.34) and more frequent with combination therapy (212 [2.49%]: HR 1.24, 1.01-1.51, p=0.038). Estimated glomerular filtration rate (eGFR) declined least with ramipril compared with telmisartan (-2.82 [SD 17.2] mL/min/1.73 m(2)vs -4.12 [17.4], p<0.0001) or combination therapy (-6.11 [17.9], p<0.0001). The increase in urinary albumin excretion was less with telmisartan (p=0.004) or with combination therapy (p=0.001) than with ramipril. \n INTERPRETATION In people at high vascular risk, telmisartan's effects on major renal outcomes are similar to ramipril. Although combination therapy reduces proteinuria to a greater extent than monotherapy, overall it worsens major renal outcomes.", "title": "Renal outcomes with telmisartan, ramipril, or both, in people at high vascular risk (the ONTARGET study): a multicentre, randomised, double-blind, controlled trial." }, { "docid": "750781", "text": "BACKGROUND Few studies have compared long-term status of bypass grafts between patients with and without diabetes, and uncertainty exists as to whether diabetes independently predicts poor clinical outcome after CABG. \n METHODS AND RESULTS Among 1526 patients in BARI who underwent CABG as initial revascularization, 99 of 292 (34%) with treated diabetes mellitus (TDM) (those on insulin or oral hypoglycemic agents) and 469 of 1234 (38%) without TDM had follow-up angiography. Angiograms with the longest interval from initial surgery and before any percutaneous graft intervention (mean 3.9 years) were reviewed. An average of 3.0 grafts were placed at initial CABG for patients with TDM (n=297; internal mammary artery [IMA], 33%) and 2.9 grafts for patients without TDM (n=1347; IMA, 34%). Patients with TDM were more likely than those without to have small (<1.5 mm) grafted distal vessels (29% versus 22%) and vessels of poor quality (9% versus 6%). On follow-up angiography, 89% of IMA grafts were free of stenoses > or =50% among patients with TDM versus 85% among patients without TDM (P=0.23). For vein grafts, the corresponding percentages were 71% versus 75% (P=0.40). After statistical adjustment, TDM was unrelated to having a graft stenosis > or =50% (adjusted odds ratio, 0.87; 95% CI, 0.58 to 1.32). \n CONCLUSIONS Despite diabetic patients' having smaller distal vessels and vessels judged to be of poorer quality, diabetes does not appear to adversely affect patency of IMA or vein grafts over an average of 4-year follow-up. Previously observed differences in survival between CABG-treated patients with and without diabetes may be largely a result of differential risk of mortality from noncardiac causes.", "title": "Coronary bypass graft patency in patients with diabetes in the Bypass Angioplasty Revascularization Investigation (BARI)." }, { "docid": "16390264", "text": "OBJECTIVES To determine the extent to which type of hospital admission (emergency compared with elective) and surgical procedure varied by socioeconomic circumstances, age, sex, and year of admission for colorectal, breast, and lung cancer. \n DESIGN Repeated cross sectional study with data from individual patients, 1 April 1999 to 31 March 2006. \n SETTING Hospital episode statistics (HES) dataset. \n PARTICIPANTS 564 821 patients aged 50 and over admitted with a diagnosis of colorectal, breast, or lung cancer. \n MAIN OUTCOME MEASURES Proportion of patients admitted as emergencies, and the proportion receiving the recommended surgical treatment. \n RESULTS Patients from deprived areas, older people, and women were more likely to be admitted as emergencies. For example, the adjusted odds ratio for patients with breast cancer in the least compared with most deprived fifth of deprivation was 0.63 (95% confidence interval 0.60 to 0.66) and the adjusted odds ratio for patients with lung cancer aged 80-89 compared with those aged 50-59 was 3.13 (2.93 to 3.34). There were some improvements in disparities between age groups but not for patients living in deprived areas over time. Patients from deprived areas were less likely to receive preferred procedures for rectal, breast, and lung cancer. These findings did not improve with time. For example, 67.4% (3529/5237) of patients in the most deprived fifth of deprivation had anterior resection for rectal cancer compared with 75.5% (4497/5959) of patients in the least deprived fifth (1.34, 1.22 to 1.47). Over half (54.0%, 11 256/20 849) of patients in the most deprived fifth of deprivation had breast conserving surgery compared with 63.7% (18 445/28 960) of patients in the least deprived fifth (1.21, 1.16 to 1.26). Men were less likely than women to undergo anterior resection and lung cancer resection and older people were less likely to receive breast conserving surgery and lung cancer resection. For example, the adjusted odds ratio for lung cancer patients aged 80-89 compared with those aged 50-59 was 0.52 (0.46 to 0.59). Conclusions Despite the implementation of the NHS Cancer Plan, social factors still strongly influence access to and the provision of care.", "title": "Social variations in access to hospital care for patients with colorectal, breast, and lung cancer between 1999 and 2006: retrospective analysis of hospital episode statistics" }, { "docid": "24921368", "text": "Impaired awareness of hypoglycaemia (IAH) is an acquired complication of insulin therapy, which affects people with type 1 and insulin-treated type 2 diabetes mellitus, whereby the ability to perceive the onset of hypoglycaemia becomes diminished or absent. Deficiencies of the counter-regulatory hormonal responses to hypoglycaemia usually co-exist. The development of IAH and counter-regulatory failure greatly increases the risk of severe hypoglycaemia. Scoring systems have been developed that can be used in the clinical setting and assist with identification of this group of individuals at risk of severe hypoglycaemia. The mainstay of treatment of IAH is the scrupulous avoidance of hypoglycaemia.", "title": "Impaired awareness of hypoglycaemia: a review." }, { "docid": "3190689", "text": "BACKGROUND Laparoscopic adhesiolysis for chronic abdominal pain is controversial and is not evidence based. We aimed to test our hypothesis that laparoscopic adhesiolysis leads to substantial pain relief and improvement in quality of life in patients with adhesions and chronic abdominal pain. \n METHODS Patients had diagnostic laparoscopy for chronic abdominal pain attributed to adhesions; other causes for their pain had been excluded. If adhesions were confirmed during diagnostic laparoscopy, patients were randomly assigned either to laparoscopic adhesiolysis or no treatment. Treatment allocation was concealed from patients, and assessors were unaware of patients' treatment and outcome. Pain was assessed for 1 year by visual analogue score (VAS) score (scale 0-100), pain change score, use of analgesics, and quality of life score. Analysis was by intention to treat. \n FINDINGS Of 116 patients enrolled for diagnostic laparoscopy, 100 were randomly allocated either laparoscopic adhesiolysis (52) or no treatment (48). Both groups reported substantial pain relief and a significantly improved quality of life, but there was no difference between the groups (mean change from baseline of VAS score at 12 months: difference 3 points, p=0.53; 95% CI -7 to 13). \n INTERPRETATION Although laparoscopic adhesiolysis relieves chronic abdominal pain, it is not more beneficial than diagnostic laparoscopy alone. Therefore, laparoscopic adhesiolysis cannot be recommended as a treatment for adhesions in patients with chronic abdominal pain.", "title": "Laparoscopic adhesiolysis in patients with chronic abdominal pain: a blinded randomised controlled multi-centre trial." }, { "docid": "58050905", "text": "The World Health Organisation has declared the period 2000 to 2010 the Bone and Joint Decade. This is indeed timely and appropriate. Hundreds of millions of people in the world today are beset with a host of disabilities caused by trauma, ageing and degeneration and other affections of the musculo-skeletal system. With the state of art of orthopaedic surgery and rheumatology, sufferers of bone and joint disabilities have benefited a great deal from advances in pharmacology, newer techniques of imaging, surgery and man-made materials to replace diseased or damaged bone and cartilage. However, man-made materials, being non-living, are subject to wear and tear and loosening in the host bone. As we advance into the Bone and Joint Decade, further improvement in the treatment of bone and joint diseases lies in more basic cartilage and bone research. The Human Genome Project has provided us with a better understanding of disease genes and the possibility of gene manipulation to prevent and treat specific diseases. Cartilage cells culture and transplant are already a reality. Tissue engineering, i.e. growing cells in three-dimensional substrates of collagen or synthetic biodegradable polymers, started in the 1980s, will in future be used to replace damaged bone and cartilage parts with living and bone and cartilaginous tissues, respectively. The first steps have been taken; more research needs to be done. And it is not unreasonable to expect a significant breakthrough in the treatment of bone and joint diseases at the end of this decade. Ann Acad Med Singapore 2002; 31:621-2", "title": "The Bone and Joint Decade 2000-2010." }, { "docid": "5687200", "text": "AIMS The aim of this study was to compare the effects of calorie-restricted vegetarian and conventional diabetic diets alone and in combination with exercise on insulin resistance, visceral fat and oxidative stress markers in subjects with Type 2 diabetes. \n METHODS A 24-week, randomized, open, parallel design was used. Seventy-four patients with Type 2 diabetes were randomly assigned to either the experimental group (n = 37), which received a vegetarian diet, or the control group (n = 37), which received a conventional diabetic diet. Both diets were isocaloric, calorie restricted (-500 kcal/day). All meals during the study were provided. The second 12 weeks of the diet were combined with aerobic exercise. Participants were examined at baseline, 12 weeks and 24 weeks. Primary outcomes were: insulin sensitivity measured by hyperinsulinaemic isoglycaemic clamp; volume of visceral and subcutaneous fat measured by magnetic resonance imaging; and oxidative stress measured by thiobarbituric acid reactive substances. Analyses were by intention to treat. \n RESULTS Forty-three per cent of participants in the experimental group and 5% of participants in the control group reduced diabetes medication (P < 0.001). Body weight decreased more in the experimental group than in the control group [-6.2 kg (95% CI -6.6 to -5.3) vs. -3.2 kg (95% CI -3.7 to -2.5); interaction group × time P = 0.001]. An increase in insulin sensitivity was significantly greater in the experimental group than in the control group [30% (95% CI 24.5-39) vs. 20% (95% CI 14-25), P = 0.04]. A reduction in both visceral and subcutaneous fat was greater in the experimental group than in the control group (P = 0.007 and P = 0.02, respectively). Plasma adiponectin increased (P = 0.02) and leptin decreased (P = 0.02) in the experimental group, with no change in the control group. Vitamin C, superoxide dismutase and reduced glutathione increased in the experimental group (P = 0.002, P < 0.001 and P = 0.02, respectively). Differences between groups were greater after the addition of exercise training. Changes in insulin sensitivity and enzymatic oxidative stress markers correlated with changes in visceral fat. \n CONCLUSIONS A calorie-restricted vegetarian diet had greater capacity to improve insulin sensitivity compared with a conventional diabetic diet over 24 weeks. The greater loss of visceral fat and improvements in plasma concentrations of adipokines and oxidative stress markers with this diet may be responsible for the reduction of insulin resistance. The addition of exercise training further augmented the improved outcomes with the vegetarian diet.", "title": "Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes" }, { "docid": "44384384", "text": "AIMS While randomized clinical trials have compared clopidogrel with higher potency adenosine diphosphate (ADP) receptor inhibitors among patients with acute myocardial infarction, little is known about the frequency, effectiveness and safety of switching between ADP receptor inhibitors in routine clinical practice. \n METHODS AND RESULTS We studied 11,999 myocardial infarction patients treated with percutaneous coronary intervention at 230 hospitals from April 2010 to October 2012 in the TRANSLATE-ACS study. Multivariable Cox regression was used to compare six-month post-discharge risks of major adverse cardiovascular events (MACE: death, myocardial infarction, stroke, or unplanned revascularization) and Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-defined bleeding between in-hospital ADP receptor inhibitor switching versus continuation of the initially selected therapy. Among 8715 patients treated initially with clopidogrel, 994 (11.4%) were switched to prasugrel or ticagrelor; switching occurred primarily after percutaneous coronary intervention (60.9%) and at the time of hospital discharge (26.7%). Among 3284 patients treated initially with prasugrel or ticagrelor, 448 (13.6%) were switched to clopidogrel; 48.2% of switches occurred after percutaneous coronary intervention and 48.0% at hospital discharge. Switching to prasugrel or ticagrelor was not associated with increased bleeding when compared with continuation on clopidogrel (2.7% vs. 3.3%, adjusted hazard ratio 0.96, 95% confidence interval 0.64-1.42, p=0.82). Switching from prasugrel or ticagrelor to clopidogrel was not associated with increased MACE (8.9% vs. 7.7%, adjusted hazard ratio 1.06, 95% confidence interval 0.75-1.49, p=0.76) when compared with continuation on the higher potency agent. \n CONCLUSIONS In-hospital ADP receptor inhibitor switching occurs in more than one in 10 myocardial infarction patients in contemporary practice. In this observational study, ADP receptor inhibitor switching does not appear to be significantly associated with increased hazard of MACE or bleeding.", "title": "In-hospital switching between adenosine diphosphate receptor inhibitors in patients with acute myocardial infarction treated with percutaneous coronary intervention: Insights into contemporary practice from the TRANSLATE-ACS study." }, { "docid": "8298120", "text": "PURPOSE Glaucoma is the leading cause of global irreversible blindness. Present estimates of global glaucoma prevalence are not up-to-date and focused mainly on European ancestry populations. We systematically examined the global prevalence of primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG), and projected the number of affected people in 2020 and 2040. \n DESIGN Systematic review and meta-analysis. \n PARTICIPANTS Data from 50 population-based studies (3770 POAG cases among 140,496 examined individuals and 786 PACG cases among 112 398 examined individuals). \n METHODS We searched PubMed, Medline, and Web of Science for population-based studies of glaucoma prevalence published up to March 25, 2013. Hierarchical Bayesian approach was used to estimate the pooled glaucoma prevalence of the population aged 40-80 years along with 95% credible intervals (CrIs). Projections of glaucoma were estimated based on the United Nations World Population Prospects. Bayesian meta-regression models were performed to assess the association between the prevalence of POAG and the relevant factors. \n MAIN OUTCOME MEASURES Prevalence and projection numbers of glaucoma cases. \n RESULTS The global prevalence of glaucoma for population aged 40-80 years is 3.54% (95% CrI, 2.09-5.82). The prevalence of POAG is highest in Africa (4.20%; 95% CrI, 2.08-7.35), and the prevalence of PACG is highest in Asia (1.09%; 95% CrI, 0.43-2.32). In 2013, the number of people (aged 40-80 years) with glaucoma worldwide was estimated to be 64.3 million, increasing to 76.0 million in 2020 and 111.8 million in 2040. In the Bayesian meta-regression model, men were more likely to have POAG than women (odds ratio [OR], 1.36; 95% CrI, 1.23-1.52), and after adjusting for age, gender, habitation type, response rate, and year of study, people of African ancestry were more likely to have POAG than people of European ancestry (OR, 2.80; 95% CrI, 1.83-4.06), and people living in urban areas were more likely to have POAG than those in rural areas (OR, 1.58; 95% CrI, 1.19-2.04). \n CONCLUSIONS The number of people with glaucoma worldwide will increase to 111.8 million in 2040, disproportionally affecting people residing in Asia and Africa. These estimates are important in guiding the designs of glaucoma screening, treatment, and related public health strategies.", "title": "Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis." }, { "docid": "154243324", "text": "Governments have shown an interest in early intervention strategies to reduce youth homelessness, but critics say that early intervention programs lack clear outcomes. This paper investigates what happens when early intervention programs are not in place and young people progress to adult homelessness. The paper assesses the 'social adaptation' hypothesis that the longer young people are homeless the more they adapt to homelessness as a way of life. The paper uses information on 1,677 individuals who first became homeless when they were 18 or younger. Three-quarters of the sample had progressed to adult homelessness (defined as 25 or older) and one-quarter were now young adults aged 19 to 24. The findings confirm that the longer people are homeless, the more difficult it becomes to get out of homelessness. However, the social adaptation account overstates the extent to which people accept homelessness as a 'way of life'. People can return to conventional accommodation if they are given long-term support. The paper concludes with three policy recommendations.", "title": "From youth to adult homelessness" }, { "docid": "1287809", "text": "IMPORTANCE The American College of Cardiology and the American Heart Association (ACC/AHA) cholesterol treatment guidelines have wide-scale implications for treating adults without history of atherosclerotic cardiovascular disease (ASCVD) with statins. \n OBJECTIVE To estimate the cost-effectiveness of various 10-year ASCVD risk thresholds that could be used in the ACC/AHA cholesterol treatment guidelines. \n DESIGN, SETTING, AND PARTICIPANTS Microsimulation model, including lifetime time horizon, US societal perspective, 3% discount rate for costs, and health outcomes. In the model, hypothetical individuals from a representative US population aged 40 to 75 years received statin treatment, experienced ASCVD events, and died from ASCVD-related or non-ASCVD-related causes based on ASCVD natural history and statin treatment parameters. Data sources for model parameters included National Health and Nutrition Examination Surveys, large clinical trials and meta-analyses for statin benefits and treatment, and other published sources. \n MAIN OUTCOMES AND MEASURES Estimated ASCVD events prevented and incremental costs per quality-adjusted life-year (QALY) gained. \n RESULTS In the base-case scenario, the current ASCVD threshold of 7.5% or higher, which was estimated to be associated with 48% of adults treated with statins, had an incremental cost-effectiveness ratio (ICER) of $37,000/QALY compared with a 10% or higher threshold. More lenient ASCVD thresholds of 4.0% or higher (61% of adults treated) and 3.0% or higher (67% of adults treated) had ICERs of $81,000/QALY and $140,000/QALY, respectively. Shifting from a 7.5% or higher ASCVD risk threshold to a 3.0% or higher ASCVD risk threshold was estimated to be associated with an additional 161,560 cardiovascular disease events averted. Cost-effectiveness results were sensitive to changes in the disutility associated with taking a pill daily, statin price, and the risk of statin-induced diabetes. In probabilistic sensitivity analysis, there was a higher than 93% chance that the optimal ASCVD threshold was 5.0% or lower using a cost-effectiveness threshold of $100,000/QALY. \n CONCLUSIONS AND RELEVANCE In this microsimulation model of US adults aged 45 to 75 years [corrected], the current 10-year ASCVD risk threshold (≥7.5% risk threshold) used in the ACC/AHA cholesterol treatment guidelines has an acceptable cost-effectiveness profile (ICER, $37,000/QALY), but more lenient ASCVD thresholds would be optimal using cost-effectiveness thresholds of $100,000/QALY (≥4.0% risk threshold) or $150,000/QALY (≥3.0% risk threshold). The optimal ASCVD threshold was sensitive to patient preferences for taking a pill daily, changes to statin price, and the risk of statin-induced diabetes.", "title": "Cost-effectiveness of 10-Year Risk Thresholds for Initiation of Statin Therapy for Primary Prevention of Cardiovascular Disease." }, { "docid": "23639838", "text": "Brain metastases occur in up to 40% of patients with cancer. Their management has been revolutionized in the last decade by three developments: improved imaging and detection of metastases, better treatment of systemic disease with the result that metastases occur more often; and improved surgical techniques including image-guided surgery to treat metastatic lesions. Class 1 data suggest that surgery is a better treatment for metastases than whole brain radiation. Other data suggest that metastases even in eloquent cortex can be removed safely. The complication rate is low and the recurrence rate is less than 10%. In general, indications for surgery include a mass with an unknown primary; a symptomatic mass including one in eloquent areas; a mass with considerable edema requiring high dose steroids; a mass greater than 3 cm; or patient preference when radiosurgery may also be an option. The question of radiosurgery or whole brain radiation as adjunct to surgical removal requires further evaluation.", "title": "Surgical Resection for Patients with Solid Brain Metastases: Current Status" }, { "docid": "5262240", "text": "AIMS To investigate the pattern of changes in HbA1c in people with Type 1 diabetes managed by long-term Continuous subcutaneous insulin infusion. \n METHODS We studied HbA1c changes using computerized clinic records in 35 adult people with Type 1 diabetes and an elevated HbA1c (≥ 64 mmol/mol, 8.0%) on multiple daily insulin injections, who were then switched to continuous subcutaneous insulin infusion for at least 5 years. \n RESULTS We identified three subgroups with similar baseline HbA1c but different long-term responses to pump therapy: group A--those with improvement followed by deterioration (57%); group B--those with improvement that was sustained throughout the 5 years (31%); and group C-those where HbA1c did not change significantly from baseline (12%). The patients in group C had a higher BMI: 31.0 ± 5.2 vs. 25.9 ± 3.3 vs. 25.2 ± 3.1 kg/m² (group C vs. group A and group B; P = 0.02). \n CONCLUSIONS Improved glycaemic control with continuous subcutaneous insulin infusion was maintained over 5 years by 88% of people with Type 1 diabetes in this study, but there were variations in the long-term efficacy, with some people improving and worsening, others maintaining strict control and a few subcutaneous insulin infusion 'non-responders'.", "title": "Variations in the quality and sustainability of long-term glycaemic control with continuous subcutaneous insulin infusion." }, { "docid": "5402581", "text": "CONTEXT Atypical antipsychotic medications are widely used to treat delusions, aggression, and agitation in people with Alzheimer disease and other dementia; however, concerns have arisen about the increased risk for cerebrovascular adverse events, rapid cognitive decline, and mortality with their use. \n OBJECTIVE To assess the evidence for increased mortality from atypical antipsychotic drug treatment for people with dementia. \n DATA SOURCES MEDLINE (1966 to April 2005), the Cochrane Controlled Trials Register (2005, Issue 1), meetings presentations (1997-2004), and information from the sponsors were searched using the terms for atypical antipsychotic drugs (aripiprazole, clozapine, olanzapine, quetiapine, risperidone, and ziprasidone), dementia, Alzheimer disease, and clinical trial. STUDY SELECTION Published and unpublished randomized placebo-controlled, parallel-group clinical trials of atypical antipsychotic drugs marketed in the United States to treat patients with Alzheimer disease or dementia were selected by consensus of the authors. \n DATA EXTRACTION Trials, baseline characteristics, outcomes, all-cause dropouts, and deaths were extracted by one reviewer; treatment exposure was obtained or estimated. Data were checked by a second reviewer. \n DATA SYNTHESIS Fifteen trials (9 unpublished), generally 10 to 12 weeks in duration, including 16 contrasts of atypical antipsychotic drugs with placebo met criteria (aripiprazole [n = 3], olanzapine [n = 5], quetiapine [n = 3], risperidone [n = 5]). A total of 3353 patients were randomized to study drug and 1757 were randomized to placebo. Outcomes were assessed using standard methods (with random- or fixed-effects models) to calculate odds ratios (ORs) and risk differences based on patients randomized and relative risks based on total exposure to treatment. There were no differences in dropouts. Death occurred more often among patients randomized to drugs (118 [3.5%] vs 40 [2.3%]. The OR by meta-analysis was 1.54; 95% confidence interval [CI], 1.06-2.23; P = .02; and risk difference was 0.01; 95% CI, 0.004-0.02; P = .01). Sensitivity analyses did not show evidence for differential risks for individual drugs, severity, sample selection, or diagnosis. \n CONCLUSIONS Atypical antipsychotic drugs may be associated with a small increased risk for death compared with placebo. This risk should be considered within the context of medical need for the drugs, efficacy evidence, medical comorbidity, and the efficacy and safety of alternatives. Individual patient analyses modeling survival and causes of death are needed.", "title": "Risk of death with atypical antipsychotic drug treatment for dementia: meta-analysis of randomized placebo-controlled trials." }, { "docid": "12584053", "text": "OBJECTIVE To measure whether the benefits of a single education and self management structured programme for people with newly diagnosed type 2 diabetes mellitus are sustained at three years. \n DESIGN Three year follow-up of a multicentre cluster randomised controlled trial in primary care, with randomisation at practice level. \n SETTING 207 general practices in 13 primary care sites in the United Kingdom. \n PARTICIPANTS 731 of the 824 participants included in the original trial were eligible for follow-up. Biomedical data were collected on 604 (82.6%) and questionnaire data on 513 (70.1%) participants. \n INTERVENTION A structured group education programme for six hours delivered in the community by two trained healthcare professional educators compared with usual care. \n MAIN OUTCOME MEASURES The primary outcome was glycated haemoglobin (HbA(1c)) levels. The secondary outcomes were blood pressure, weight, blood lipid levels, smoking status, physical activity, quality of life, beliefs about illness, depression, emotional impact of diabetes, and drug use at three years. \n RESULTS HbA(1c) levels at three years had decreased in both groups. After adjusting for baseline and cluster the difference was not significant (difference -0.02, 95% confidence interval -0.22 to 0.17). The groups did not differ for the other biomedical and lifestyle outcomes and drug use. The significant benefits in the intervention group across four out of five health beliefs seen at 12 months were sustained at three years (P<0.01). Depression scores and quality of life did not differ at three years. \n CONCLUSION A single programme for people with newly diagnosed type 2 diabetes mellitus showed no difference in biomedical or lifestyle outcomes at three years although there were sustained improvements in some illness beliefs. \n TRIAL REGISTRATION Current Controlled Trials ISRCTN17844016.", "title": "Effectiveness of a diabetes education and self management programme (DESMOND) for people with newly diagnosed type 2 diabetes mellitus: three year follow-up of a cluster randomised controlled trial in primary care" }, { "docid": "6751418", "text": "UNLABELLED In patients with a large, multinodular goiter (> 100 g), radiation absorbed doses in the thyroid, surrounding tissues and remainder of the body were estimated after therapeutic administration of 131I(3.7 MBq or 100 microCi/g of thyroid tissue retained at 24 hr). \n METHODS Thermoluminescent dosimeter (TLD) measurements were performed on 23 patients (12 euthyroid and 1I hyperthyroid; thyroid weight 222 +/- 72 g; 2.1 +/- 0.9 GBq 131I) on the skin over the thyroid, over the submandibular gland and over the parotid gland. Thyroid radioactivity measurements were done daily in 6 euthyroid and 6 hyperthyroid patients (thyroid weight 204 +/- 69 g; 1.9 +/- 0.9 GBq 131I). An iodine biokinetic model and the MIRD methodology were used to estimate absorbed doses in organs. Cancer risks were calculated using ICRP Publication 60. \n RESULTS Cumulated absorbed doses on the skin (TLD measurements) were 4.2 +/- 1.4 Gy (thyroid), 1.2 +/- 0.6 Gy (submandibular) and 0.4 +/- 0.2 Gy (parotid). All these values were significantly correlated with the amount of radioiodine retained in the thyroid at 24 hr (euthyroid versus hyperthyroid not significant). Absorbed doses in the thyroid of 94 +/- 25 Gy for euthyroid and 93 +/- 17 Gy for hyperthyroid patients were calculated (thyroid radioactivity measurements). Extrathyroidal absorbed doses (means of 12 patients) were 0.88 Gy in the urinary bladder, 0.57 Gy in the small intestine, 0.38 Gy in the stomach, and ranged from 0.05 to 0.30 Gy in other organs (euthyroid versus hyperthyroid not significant). A 1.6% life-time risk of development of cancer outside the thyroid gland was calculated. When applied to people of 65 yr and older the estimated risk is approximately 0.5%. \n CONCLUSION These data may help in choosing the treatment regimen for individual patients with a large, multinodular goiter, who have to be treated for hyperthyroidism or compressive problems. In younger patients, surgery may be preferred. However, for elderly patients and patients with cardiopulmonary disease, the advantages of noninvasive radioiodine treatment will outweight the life-time risk of this mode of therapy.", "title": "Dosimetry and risk estimates of radioiodine therapy for large, multinodular goiters." }, { "docid": "43122426", "text": "We studied 201 consecutive patients who received a relatively fixed dose of radioiodine for the treatment of hyperthyroidism between the years 1981-6. Patients with Graves' disease (170) were initially treated with a mean (SE) dose of 369 (10) MBq 131-I with a remission rate of 94% at 6 months and a cumulative relapse rate of 12% at one year and 21% at 5 years. The cumulative incidence of hypothyroidism was 26% at 3 months, 55% at 6 months, 61% at 1 year and 66% at 5 years. Patients with a uninodular goitre (10) were initially treated with a mean (SE) dose of 438 (85) MBq 131-I with a remission rate of 100% at 6 months, without relapse at 1 year but relapsing in 17% at 5 years. The cumulative incidence of hypothyroidism was 26% at 3 months, 30% at 6 months, 40% at 1 year and 40% at 5 years. Patients with a multinodular goitre (21) were initially treated with a mean (SE) dose of 613 (77) MBq 131-I with a remission rate of 79% at 6 months and a cumulative relapse rate of 26% at 1 year and 39% at 5 years. The cumulative incidence of hypothyroidism was 5% at 3 months, 14% at 6 months, 24% at 1 year and 24% at 5 years.", "title": "131-I radioiodine therapy for hyperthyroidism in patients with Graves' disease, uninodular goitre and multinodular goitre." } ]

[ { "docid": "7873737", "text": "BACKGROUND Diabetes mellitus is a major risk factor for adverse outcomes after acute coronary syndromes (ACS). Because this disease may be associated with increased platelet aggregation, we investigated whether diabetic patients with ACS derive particular benefit from platelet glycoprotein (GP) IIb/IIIa receptor inhibition. \n METHODS AND RESULTS We performed a meta-analysis of the diabetic populations enrolled in the 6 large-scale platelet GP IIb/IIIa inhibitor ACS trials: PRISM, PRISM-PLUS, PARAGON A, PARAGON B, PURSUIT, and GUSTO IV. Among 6458 diabetic patients, platelet GP IIb/IIIa inhibition was associated with a significant mortality reduction at 30 days, from 6.2% to 4.6% (OR 0.74; 95% CI 0.59 to 0.92; P=0.007). Conversely, 23 072 nondiabetic patients had no survival benefit (3.0% versus 3.0%). The interaction between platelet GP IIb/IIIa inhibition and diabetic status was statistically significant (P=0.036). Among 1279 diabetic patients undergoing percutaneous coronary intervention (PCI) during index hospitalization, the use of these agents was associated with a mortality reduction at 30 days from 4.0% to 1.2% (OR 0.30; 95% CI 0.14 to 0.69; P=0.002). \n CONCLUSIONS This meta-analysis, including the entire large-scale trial experience of intravenous platelet GP IIb/IIIa inhibitors for the medical management of non-ST-segment-elevation ACS, shows that these agents may significantly reduce mortality at 30 days in diabetic patients. Although not based on a randomized assessment, the survival benefit appears to be of greater magnitude in patients undergoing PCI. Therefore, the use of platelet GP IIb/IIIa inhibitors should be strongly considered in diabetic patients with ACS.", "title": "Platelet glycoprotein IIb/IIIa inhibitors reduce mortality in diabetic patients with non-ST-segment-elevation acute coronary syndromes." }, { "docid": "5884524", "text": "BACKGROUND Although unstable coronary artery disease is the most common reason for admission to a coronary care unit, the long-term prognosis of patients with this diagnosis is unknown. This is particularly true for patients with diabetes mellitus, who are known to have a high morbidity and mortality after an acute myocardial infarction. \n METHODS AND RESULTS Prospectively collected data from 6 different countries in the Organization to Assess Strategies for Ischemic Syndromes (OASIS) registry were analyzed to determine the 2-year prognosis of diabetic and nondiabetic patients who were hospitalized with unstable angina or non-Q-wave myocardial infarction. Overall, 1718 of 8013 registry patients (21%) had diabetes. Diabetic patients had a higher rate of coronary bypass surgery than nondiabetic patients (23% versus 20%, P:<0.001) but had similar rates of catheterization and angioplasty. Diabetes independently predicted mortality (relative risk [RR], 1.57; 95% CI, 1.38 to 1.81; P:<0.001), as well as cardiovascular death, new myocardial infarction, stroke, and new congestive heart failure. Moreover, compared with their nondiabetic counterparts, women had a significantly higher risk than men (RR, 1.98; 95% CI, 1.60 to 2.44; and RR, 1.28; 95% CI, 1.06 to 1.56, respectively). Interestingly, diabetic patients without prior cardiovascular disease had the same event rates for all outcomes as nondiabetic patients with previous vascular disease. \n CONCLUSIONS Hospitalization for unstable angina or non-Q-wave myocardial infarction predicts a high 2-year morbidity and mortality; this is especially evident for patients with diabetes. Diabetic patients with no previous cardiovascular disease have the same long-term morbidity and mortality as nondiabetic patients with established cardiovascular disease after hospitalization for unstable coronary artery disease.", "title": "Impact of diabetes on long-term prognosis in patients with unstable angina and non-Q-wave myocardial infarction: results of the OASIS (Organization to Assess Strategies for Ischemic Syndromes) Registry." } ]

[ { "docid": "19308127", "text": "BACKGROUND P2Y12 inhibitor switching has appeared in clinical practice as a consequence of prasugrel and ticagrelor availability, apart from clopidogrel, for use in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). \n METHODS In the context of the GReek AntiPlatelet REgistry (GRAPE) we assessed the prevalence, predictive factors and short-term outcome of in-hospital P2Y12 inhibitor switching in 1794 ACS patients undergoing PCI. \n RESULTS Switching occurred in 636 (35.5%) patients of which in the form of clopidogrel to a novel agent, novel agent to clopidogrel and between prasugrel and ticagrelor in 574 (90.4%), 34 (5.3%) and 27 (4.3%) patients, respectively. Presentation to non PCI-capable hospital, bivalirudin use, age ≥75 years (inverse predictor), and regional trends emerged as predictive factors of switching to a novel agent. At combined in-hospital and one-month follow-up, propensity matched pairs analysis showed no differences in major adverse cardiovascular (MACE) or bleeding events between switching from clopidogrel to a novel agent vs novel agent constant administration. More Bleeding Academic Research Consortium type 1, type 2 and any type events and fewer MACE were seen when switching from clopidogrel to a novel agent vs only clopidogrel administration (23.7%, 3.8%, 30.6%, 1.2% vs 8.9%, 1.2%, 12.0%, 3.8% with P < .001, P = .03, P < .001 and P = .03 respectively). \n CONCLUSIONS In a real-life experience with contemporary antiplatelet treatment in ACS patients undergoing PCI, in-hospital switching represents common clinical practice. Clinical factors and regional practice differences seem to affect this strategy's choice, while switching to a novel agent may be associated with higher risk of bleeding.", "title": "In-hospital switching of oral P2Y12 inhibitor treatment in patients with acute coronary syndrome undergoing percutaneous coronary intervention: prevalence, predictors and short-term outcome." }, { "docid": "23783727", "text": "AIMS patients with diabetes mellitus (DM) have high platelet reactivity and are at increased risk of ischaemic events and bleeding post-acute coronary syndromes (ACS). In the PLATelet inhibition and patient Outcomes (PLATO) trial, ticagrelor reduced the primary composite endpoint of cardiovascular death, myocardial infarction, or stroke, but with similar rates of major bleeding compared with clopidogrel. We aimed to investigate the outcome with ticagrelor vs. clopidogrel in patients with DM or poor glycaemic control. \n METHODS AND RESULTS we analysed patients with pre-existing DM (n = 4662), including 1036 patients on insulin, those without DM (n = 13 951), and subgroups based on admission levels of haemoglobin A1c (HbA1c; n = 15 150). In patients with DM, the reduction in the primary composite endpoint (HR: 0.88, 95% CI: 0.76-1.03), all-cause mortality (HR: 0.82, 95% CI: 0.66-1.01), and stent thrombosis (HR: 0.65, 95% CI: 0.36-1.17) with no increase in major bleeding (HR: 0.95, 95% CI: 0.81-1.12) with ticagrelor was consistent with the overall cohort and without significant diabetes status-by-treatment interactions. There was no heterogeneity between patients with or without ongoing insulin treatment. ticagrelor reduced the primary endpoint, all-cause mortality, and stent thrombosis in patients with HbA1c above the median (HR: 0.80, 95% CI: 0.70-0.91; HR: 0.78, 95% CI: 0.65-0.93; and HR: 0.62, 95% CI: 0.39-1.00, respectively) with similar bleeding rates (HR: 0.98, 95% CI: 0.86-1.12). \n CONCLUSION ticagrelor, when compared with clopidogrel, reduced ischaemic events in ACS patients irrespective of diabetic status and glycaemic control, without an increase in major bleeding events.", "title": "Ticagrelor vs. clopidogrel in patients with acute coronary syndromes and diabetes: a substudy from the PLATelet inhibition and patient Outcomes (PLATO) trial" }, { "docid": "44827480", "text": "BACKGROUND Few data exist about the implementation of contemporary oral antiplatelet treatment guidelines in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). \n METHODS GReek AntiPlatelet rEgistry (GRAPE), initiated on January 2012, is a prospective, observational, multicenter cohort study focusing on contemporary use of P2Y12 inhibitors. In 1434 patients we evaluated appropriateness of P2Y12 selection initially and at discharge by applying an eligibility-assessing algorithm based on P2Y12 inhibitors' contraindications/specific warnings and precautions. \n RESULTS Appropriate, less preferable and inappropriate P2Y12 inhibitor selections were made initially in 45.8%, 47.2% and 6.6% and at discharge in 64.1%, 29.2% and 6.6% of patients, respectively. The selection of clopidogrel was most commonly less preferable, both initially (69.7%) and at discharge (75.6%). Appropriate selection of newer agents was high initially (79.2%-82.8%), with further increase as selection at discharge (89.4%-89.8%). Inappropriate selection of the newer agents was 17.2%-20.8% initially, decreasing to 10.2%-10.6% at discharge. Conditions and co-medications related to increased bleeding risk, presentation with ST elevation myocardial infarction and the absence of reperfusion within the first 24h were the most powerful predictors of appropriate P2Y12 selection initially, whereas age ≥75 years, conditions and co-medications related to increased bleeding risk and regional trends mostly affected appropriate P2Y12 selection at discharge. \n CONCLUSIONS In GRAPE, adherence with the recently released guidelines on oral antiplatelet therapy was satisfactory. Clopidogrel was most commonly used as a less preferable selection, while prasugrel or ticagrelor selection was mostly appropriate. Certain factors may predict initial and at discharge guideline implementation. Clinical Trial Registration-clinicaltrials.gov Identifier: NCT01774955 http://clinicaltrials.gov/.", "title": "Implementation of contemporary oral antiplatelet treatment guidelines in patients with acute coronary syndrome undergoing percutaneous coronary intervention: a report from the GReek AntiPlatelet rEgistry (GRAPE)." }, { "docid": "6158879", "text": "BACKGROUND Patients with diabetes mellitus (DM) are at high risk for recurrent cardiovascular events after acute coronary syndromes, in part because of increased platelet reactivity. The Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction 38 (TRITON-TIMI 38) showed an overall reduction in ischemic events with more intensive antiplatelet therapy with prasugrel than with clopidogrel but with more bleeding. We compared prasugrel with clopidogrel among subjects with DM in TRITON-TIMI 38. \n METHODS AND RESULTS We classified 13 608 subjects on the basis of preexisting history of DM and further according to insulin use. Prespecified analyses of the primary (cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke) and key secondary end points, including net clinical benefit (death, nonfatal myocardial infarction, nonfatal stroke, and nonfatal TIMI major bleeding) were compared by use of the log-rank test. We found that 3146 subjects had a preexisting history of DM, including 776 receiving insulin. The primary end point was reduced significantly with prasugrel among subjects without DM (9.2% versus 10.6%; hazard ratio [HR], 0.86; P=0.02) and with DM (12.2% versus 17.0%; HR, 0.70; P<0.001, P(interaction)=0.09). A benefit for prasugrel was observed among DM subjects on insulin (14.3% versus 22.2%; HR, 0.63; P=0.009) and those not on insulin (11.5% versus 15.3%; HR, 0.74; P=0.009). Myocardial infarction was reduced with prasugrel by 18% among subjects without DM (7.2% versus 8.7%; HR, 0.82; P=0.006) and by 40% among subjects with DM (8.2% versus 13.2%; HR, 0.60; P<0.001, P(interaction)=0.02). Although TIMI major hemorrhage was increased among subjects without DM on prasugrel (1.6% versus 2.4%; HR, 1.43; P=0.02), the rates were similar among subjects with DM for clopidogrel and prasugrel (2.6% versus 2.5%; HR, 1.06; P=0.81, P(interaction)=0.29). Net clinical benefit with prasugrel was greater for subjects with DM (14.6% versus 19.2%; HR, 0.74; P=0.001) than for subjects without DM (11.5% versus 12.3%; HR, 0.92; P=0.16, P(interaction)=0.05). \n CONCLUSIONS Subjects with DM tended to have a greater reduction in ischemic events without an observed increase in TIMI major bleeding and therefore a greater net treatment benefit with prasugrel compared with clopidogrel. These data demonstrate that the more intensive oral antiplatelet therapy provided with prasugrel is of particular benefit to patients with DM.", "title": "Greater clinical benefit of more intensive oral antiplatelet therapy with prasugrel in patients with diabetes mellitus in the trial to assess improvement in therapeutic outcomes by optimizing platelet inhibition with prasugrel-Thrombolysis in Myocardial Infarction 38." }, { "docid": "35495268", "text": "BACKGROUND Weight loss is recommended for overweight or obese patients with type 2 diabetes on the basis of short-term studies, but long-term effects on cardiovascular disease remain unknown. We examined whether an intensive lifestyle intervention for weight loss would decrease cardiovascular morbidity and mortality among such patients. \n METHODS In 16 study centers in the United States, we randomly assigned 5145 overweight or obese patients with type 2 diabetes to participate in an intensive lifestyle intervention that promoted weight loss through decreased caloric intake and increased physical activity (intervention group) or to receive diabetes support and education (control group). The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina during a maximum follow-up of 13.5 years. \n RESULTS The trial was stopped early on the basis of a futility analysis when the median follow-up was 9.6 years. Weight loss was greater in the intervention group than in the control group throughout the study (8.6% vs. 0.7% at 1 year; 6.0% vs. 3.5% at study end). The intensive lifestyle intervention also produced greater reductions in glycated hemoglobin and greater initial improvements in fitness and all cardiovascular risk factors, except for low-density-lipoprotein cholesterol levels. The primary outcome occurred in 403 patients in the intervention group and in 418 in the control group (1.83 and 1.92 events per 100 person-years, respectively; hazard ratio in the intervention group, 0.95; 95% confidence interval, 0.83 to 1.09; P=0.51). \n CONCLUSIONS An intensive lifestyle intervention focusing on weight loss did not reduce the rate of cardiovascular events in overweight or obese adults with type 2 diabetes. (Funded by the National Institutes of Health and others; Look AHEAD ClinicalTrials.gov number, NCT00017953.).", "title": "Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes." }, { "docid": "3462075", "text": "Background CD19‐specific chimeric antigen receptor (CAR) T cells induce high rates of initial response among patients with relapsed B‐cell acute lymphoblastic leukemia (ALL) and long‐term remissions in a subgroup of patients. Methods We conducted a phase 1 trial involving adults with relapsed B‐cell ALL who received an infusion of autologous T cells expressing the 19‐28z CAR at the Memorial Sloan Kettering Cancer Center (MSKCC). Safety and long‐term outcomes were assessed, as were their associations with demographic, clinical, and disease characteristics. Results A total of 53 adults received 19‐28z CAR T cells that were manufactured at MSKCC. After infusion, severe cytokine release syndrome occurred in 14 of 53 patients (26%; 95% confidence interval [CI], 15 to 40); 1 patient died. Complete remission was observed in 83% of the patients. At a median follow‐up of 29 months (range, 1 to 65), the median event‐free survival was 6.1 months (95% CI, 5.0 to 11.5), and the median overall survival was 12.9 months (95% CI, 8.7 to 23.4). Patients with a low disease burden (<5% bone marrow blasts) before treatment had markedly enhanced remission duration and survival, with a median event‐free survival of 10.6 months (95% CI, 5.9 to not reached) and a median overall survival of 20.1 months (95% CI, 8.7 to not reached). Patients with a higher burden of disease (≥5% bone marrow blasts or extramedullary disease) had a greater incidence of the cytokine release syndrome and neurotoxic events and shorter long‐term survival than did patients with a low disease burden. Conclusions In the entire cohort, the median overall survival was 12.9 months. Among patients with a low disease burden, the median overall survival was 20.1 months and was accompanied by a markedly lower incidence of the cytokine release syndrome and neurotoxic events after 19‐28z CAR T‐cell infusion than was observed among patients with a higher disease burden. (Funded by the Commonwealth Foundation for Cancer Research and others; ClinicalTrials.gov number, NCT01044069.)", "title": "Long‐Term Follow‐up of CD19 CAR Therapy in Acute Lymphoblastic Leukemia" }, { "docid": "25028913", "text": "BACKGROUND In patients with unstable coronary artery disease, there is a relation between the short-term risk of death and blood levels of troponin T (a marker of myocardial damage) and C-reactive protein and fibrinogen (markers of inflammation). Using information obtained during an extension of the follow-up period in the Fragmin during Instability in Coronary Artery Disease trial, we evaluated the usefulness of troponin T, C-reactive protein, and fibrinogen levels and other indicators of risk as predictors of the long-term risk of death from cardiac causes. \n METHODS Levels of C-reactive protein and fibrinogen at enrollment and the maximal level of troponin T during the first 24 hours after enrollment were analyzed in 917 patients included in a clinical trial of low-molecular-weight heparin in unstable coronary artery disease. The patients were followed for a mean of 37.0 months (range, 1.6 to 50.6). \n RESULTS During follow-up, 1.2 percent of the 173 patients with maximal blood troponin T levels of less than 0.06 microg per liter died of cardiac causes, as compared with 8.7 percent of the 367 patients with levels of 0.06 to 0.59 microg per liter and 15.4 percent of the 377 patients with levels of at least 0.60 microg per liter (P=0.007 and P=0.001, respectively). The rates of death from cardiac causes were 5.7 percent among the 314 patients with blood C-reactive protein levels of less than 2 mg per liter, 7.8 percent among the 294 with levels of 2 to 10 mg per liter, and 16.5 percent among the 309 with levels of more than 10 mg per liter (P=0.29 and P=0.001, respectively). The rates of death from cardiac causes were 5.4 percent among the 314 patients with blood fibrinogen levels of less than 3.4 g per liter, 12.0 percent among the 300 with levels of 3.4 to 3.9 g per liter, and 12.9 percent among the 303 with levels of at least 4.0 g per liter (P=0.004 and P=0.69, respectively). In a multivariate analysis, levels of troponin T and C-reactive protein were independent predictors of the risk of death from cardiac causes. \n CONCLUSIONS In unstable coronary artery disease, elevated levels of troponin T and C-reactive protein are strongly related to the long-term risk of death from cardiac causes. These markers are independent risk factors, and their effects are additive with respect to each other and other clinical indicators of risk.", "title": "Markers of myocardial damage and inflammation in relation to long-term mortality in unstable coronary artery disease. FRISC Study Group. Fragmin during Instability in Coronary Artery Disease." }, { "docid": "44384384", "text": "AIMS While randomized clinical trials have compared clopidogrel with higher potency adenosine diphosphate (ADP) receptor inhibitors among patients with acute myocardial infarction, little is known about the frequency, effectiveness and safety of switching between ADP receptor inhibitors in routine clinical practice. \n METHODS AND RESULTS We studied 11,999 myocardial infarction patients treated with percutaneous coronary intervention at 230 hospitals from April 2010 to October 2012 in the TRANSLATE-ACS study. Multivariable Cox regression was used to compare six-month post-discharge risks of major adverse cardiovascular events (MACE: death, myocardial infarction, stroke, or unplanned revascularization) and Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-defined bleeding between in-hospital ADP receptor inhibitor switching versus continuation of the initially selected therapy. Among 8715 patients treated initially with clopidogrel, 994 (11.4%) were switched to prasugrel or ticagrelor; switching occurred primarily after percutaneous coronary intervention (60.9%) and at the time of hospital discharge (26.7%). Among 3284 patients treated initially with prasugrel or ticagrelor, 448 (13.6%) were switched to clopidogrel; 48.2% of switches occurred after percutaneous coronary intervention and 48.0% at hospital discharge. Switching to prasugrel or ticagrelor was not associated with increased bleeding when compared with continuation on clopidogrel (2.7% vs. 3.3%, adjusted hazard ratio 0.96, 95% confidence interval 0.64-1.42, p=0.82). Switching from prasugrel or ticagrelor to clopidogrel was not associated with increased MACE (8.9% vs. 7.7%, adjusted hazard ratio 1.06, 95% confidence interval 0.75-1.49, p=0.76) when compared with continuation on the higher potency agent. \n CONCLUSIONS In-hospital ADP receptor inhibitor switching occurs in more than one in 10 myocardial infarction patients in contemporary practice. In this observational study, ADP receptor inhibitor switching does not appear to be significantly associated with increased hazard of MACE or bleeding.", "title": "In-hospital switching between adenosine diphosphate receptor inhibitors in patients with acute myocardial infarction treated with percutaneous coronary intervention: Insights into contemporary practice from the TRANSLATE-ACS study." }, { "docid": "38630735", "text": "BACKGROUND Atherosclerotic plaques that lead to acute coronary syndromes often occur at sites of angiographically mild coronary-artery stenosis. Lesion-related risk factors for such events are poorly understood. \n METHODS In a prospective study, 697 patients with acute coronary syndromes underwent three-vessel coronary angiography and gray-scale and radiofrequency intravascular ultrasonographic imaging after percutaneous coronary intervention. Subsequent major adverse cardiovascular events (death from cardiac causes, cardiac arrest, myocardial infarction, or rehospitalization due to unstable or progressive angina) were adjudicated to be related to either originally treated (culprit) lesions or untreated (nonculprit) lesions. The median follow-up period was 3.4 years. \n RESULTS The 3-year cumulative rate of major adverse cardiovascular events was 20.4%. Events were adjudicated to be related to culprit lesions in 12.9% of patients and to nonculprit lesions in 11.6%. Most nonculprit lesions responsible for follow-up events were angiographically mild at baseline (mean [±SD] diameter stenosis, 32.3±20.6%). However, on multivariate analysis, nonculprit lesions associated with recurrent events were more likely than those not associated with recurrent events to be characterized by a plaque burden of 70% or greater (hazard ratio, 5.03; 95% confidence interval [CI], 2.51 to 10.11; P<0.001) or a minimal luminal area of 4.0 mm(2) or less (hazard ratio, 3.21; 95% CI, 1.61 to 6.42; P=0.001) or to be classified on the basis of radiofrequency intravascular ultrasonography as thin-cap fibroatheromas (hazard ratio, 3.35; 95% CI, 1.77 to 6.36; P<0.001). \n CONCLUSIONS In patients who presented with an acute coronary syndrome and underwent percutaneous coronary intervention, major adverse cardiovascular events occurring during follow-up were equally attributable to recurrence at the site of culprit lesions and to nonculprit lesions. Although nonculprit lesions that were responsible for unanticipated events were frequently angiographically mild, most were thin-cap fibroatheromas or were characterized by a large plaque burden, a small luminal area, or some combination of these characteristics, as determined by gray-scale and radiofrequency intravascular ultrasonography. (Funded by Abbott Vascular and Volcano; ClinicalTrials.gov number, NCT00180466.).", "title": "A prospective natural-history study of coronary atherosclerosis." }, { "docid": "6123521", "text": "The brain interprets experiences and translates them into behavioral and physiological responses. Stressful events are those which are threatening or, at the very least, unexpected and surprising, and the physiological and behavioral responses are intended to promote adaptation via a process called \"allostasis. \" Chemical mediators of allostasis include cortisol and adrenalin from the adrenal glands, other hormones, and neurotransmitters, the parasympathetic and sympathetic nervous systems, and cytokines and chemokines from the immune system. Two brain structures, the amygdala and hippocampus, play key roles in interpreting what is stressful and determining appropriate responses. The hippocampus, a key structure for memories of events and contexts, expresses receptors that enable it to respond to glucocorticoid hormones in the blood, it undergoes atrophy in a number of psychiatric disorders; it also responds to stressors with changes in excitability, decreased dendritic branching, and reduction in number of neurons in the dentate gyrus. The amygdala, which is important for \"emotional memories, \" becomes hyperactive in posttraumatic stress disorder and depressive illness, in animal models of stress, there is evidence for growth and hypertrophy of nerve cells in the amygdala. Changes in the brain after acute and chronic stressors mirror the pattern seen in the metabolic, cardiovascular, and immune systems, that is, short-term adaptation (allostasis) followed by long-term damage (allostatic load), eg, atherosclerosis, fat deposition obesity, bone demineralization, and impaired immune function. Allostatic load of this kind is seen in major depressive illness and may also be expressed in other chronic anxiety and mood disorders.", "title": "Structural plasticity of the adult brain: how animal models help us understand brain changes in depression and systemic disorders related to depression" }, { "docid": "24150328", "text": "BACKGROUND Patients with metabolic syndrome are at increased risk for cardiovascular complications. We sought to determine whether peroxisome proliferator-activated receptor gamma agonists had any beneficial effect on patients with metabolic syndrome undergoing percutaneous coronary intervention (PCI). \n METHODS A total of 200 patients with metabolic syndrome undergoing PCI were randomized to rosiglitazone or placebo and followed for 1 year. Carotid intima-medial thickness (CIMT), inflammatory markers, lipid levels, brain natriuretic peptide, and clinical events were measured at baseline, 6 months, and 12 months. \n RESULTS There was no significant difference in CIMT between the 2 groups. There was no difference in the 12-month composite end point of death, myocardial infarction (MI), stroke, or any recurrent ischemia (31.4% vs 30.2%, P = .99). The rate of death, MI, or stroke at 12 months was numerically lower in the rosiglitazone group (11.9% vs 6.4%, P = .19). There was a trend toward a greater decrease over time in high-sensitivity C-reactive protein values compared with baseline in the group randomized to rosiglitazone versus placebo both at 6 months (-35.4% vs -15.8%, P = .059) and 12 months (-40.0% vs -20.9%, P = .089) and higher change in high-density lipoprotein (+15.5% vs +4.1%, P = .05) and lower triglycerides (-13.9% vs +14.9%, P = .004) in the rosiglitazone arm. There was a trend toward less new onset diabetes in the rosiglitazone group (0% vs 3.3%, P = .081) and no episodes of symptomatic hypoglycemia. There was no excess of new onset of clinical heart failure in the rosiglitazone group, nor was there a significant change in brain natriuretic peptide levels. \n CONCLUSIONS Patients with metabolic syndrome presenting for PCI are at increased risk for subsequent cardiovascular events. Rosiglitazone for 12 months did not appear to affect CIMT in this population, although it did have beneficial effects on high-sensitivity C-reactive protein, high-density lipoprotein, and triglycerides. Further study of peroxisome proliferator-activated receptor agonism in patients with metabolic syndrome undergoing PCI may be warranted.", "title": "Peroxisome proliferator-activated receptor gamma agonists for the Prevention of Adverse events following percutaneous coronary Revascularization--results of the PPAR study." }, { "docid": "20887554", "text": "BACKGROUND C-reactive protein (CRP) is a known risk factor for cardiovascular events in the healthy population and in patients with coronary artery disease. High CRP levels before cardiac surgery are associated with worse short-term outcome, but its role after discharge home remains unknown. The study objective was to evaluate the effect of CRP on short-term and mid-term outcome after cardiac surgery. \n METHODS From August 2000 to May 2004, values for preoperative CRP were available for 597 unselected patients undergoing cardiac operations. CRP was used to divide this cohort in two groups: a low inflammatory status (LHS) group of 354 patients with CRP of less than 0.5 mg/dL, and a high inflammatory status (HIS) group of 243 patients with a CRP of 0.5 mg/dL or more. Follow-up lasted a maximum of 3 years (median, 1.8 +/- 1.5 years) and was 92.6% complete. \n RESULTS In-hospital mortality was 8.2% in the HIS group and 3.4% in the LIS group (odds ratio [OR], 2.61; p = 0.02). Incidence of postoperative infections was 16.5% in the HIS group and 5.1% in the LIS group (OR, 3.25; p = 0.0001). Sternal wound infections were also more frequent in the HIS group (10.7% versus 2.8%; OR, 3.43; p = 0.002). During follow-up, the HIS group had worse survival (88.5% +/- 2.9% versus 91.9% +/- 2.5%; OR, 1.93; p = 0.05) and a higher need of hospitalization for cardiac-related causes (73.6% +/- 6% versus 86.5% +/- 3.2%; OR, 1.82; p = 0.05). \n CONCLUSIONS Patients undergoing cardiac surgery with a CRP level of 0.5 mg/dL or more are exposed to a higher risk of in-hospital mortality and postoperative infections. Despite surgical correction of cardiac disease, a high preoperative CRP value is an independent risk factor for mid-term survival and hospitalization for cardiac causes.", "title": "Preoperative C-reactive protein predicts mid-term outcome after cardiac surgery." }, { "docid": "7640792", "text": "CONTEXT Conflicting information exists about whether sex differences modulate short-term mortality following acute coronary syndromes (ACS). \n OBJECTIVES To investigate the relationship between sex and 30-day mortality in ACS, and to determine whether this relationship was modified by clinical syndrome or coronary anatomy using a large database across the spectrum of ACS and adjusting for potentially confounding clinical covariates. \n DESIGN, SETTING, AND PARTICIPANTS A convenience sample of patients pooled from 11 independent, international, randomized ACS clinical trials between 1993 and 2006 whose databases are maintained at the Duke Clinical Research Institute, Durham, North Carolina. Of 136 247 patients, 38 048 (28%) were women; 102 004 (26% women) with ST-segment elevation myocardial infarction (STEMI), 14 466 (29% women) with non-STEMI (NSTEMI), and 19 777 (40% women) with unstable angina. \n MAIN OUTCOME MEASURE Thirty-day mortality following ACS. \n RESULTS Thirty-day mortality was 9.6% in women and 5.3% in men (odds ratio [OR], 1.91; 95% confidence interval [CI], 1.83-2.00). After multivariable adjustment, mortality was not significantly different between women and men (adjusted OR, 1.06; 95% CI, 0.99-1.15). A significant sex by type of ACS interaction was demonstrated (P < .001). In STEMI, 30-day mortality was higher among women (adjusted OR, 1.15; 95% CI, 1.06-1.24), whereas in NSTEMI (adjusted OR, 0.77; 95% CI, 0.63-0.95) and unstable angina, mortality was lower among women (adjusted OR, 0.55; 95% CI, 0.43-0.70). In a cohort of 35 128 patients with angiographic data, women more often had nonobstructive (15% vs 8%) and less often had 2-vessel (25% vs 28%) and 3-vessel (23% vs 26%) coronary disease, regardless of ACS type. After additional adjustment for angiographic disease severity, 30-day mortality among women was not significantly different than men, regardless of ACS type. The relationship between sex and 30-day mortality was similar across the levels of angiographic disease severity (P for interaction = .70). \n CONCLUSIONS Sex-based differences existed in 30-day mortality among patients with ACS and vary depending on clinical presentation. However, these differences appear to be largely explained by clinical differences at presentation and severity of angiographically documented disease.", "title": "Sex differences in mortality following acute coronary syndromes." }, { "docid": "29253460", "text": "OBJECTIVE To assess whether sex differences exist in the angiographic severity, management and outcomes of acute coronary syndromes (ACS). \n METHODS The study comprised 7638 women and 19 117 men with ACS who underwent coronary angiography and were included in GRACE (Global Registry of Acute Coronary Events) from 1999-2006. Normal vessels/mild disease was defined as <50% stenosis in all epicardial vessels; advanced disease was defined as >or=one vessel with >or=50% stenosis. \n RESULTS Women were older than men and had higher rates of cardiovascular risk factors. Men and women presented equally with chest pain; however, jaw pain and nausea were more frequent among women. Women were more likely to have normal/mild disease (12% vs 6%, p<0.001) and less likely to have left-main and three-vessel disease (27% vs 32%, p<0.001) or undergo percutaneous coronary intervention (65% vs 68%, p<0.001). Women and men with normal and mild disease were treated less aggressively than those with advanced disease. Women with advanced disease had a higher risk of death (4% vs 3%, p<0.01). After adjustment for age and extent of disease, women were more likely to have adverse outcomes (death, myocardial infarction, stroke and rehospitalisation) at six months compared to men (odds ratio 1.24, 95% confidence interval 1.14 to 1.34); however, sex differences in mortality were no longer statistically significant. \n CONCLUSIONS Women with ACS were more likely to have cardiovascular disease risk factors and atypical symptoms such as nausea compared with men, but were more likely to have normal/mild angiographic coronary artery disease. Further study regarding sex differences related to disease severity is warranted.", "title": "Sex-related differences in the presentation, treatment and outcomes among patients with acute coronary syndromes: the Global Registry of Acute Coronary Events." }, { "docid": "29526125", "text": "BACKGROUND A major challenge for physicians is to identify patients with acute coronary syndromes who may benefit from treatment with glycoprotein-IIb/IIIa-receptor antagonists. We investigated whether troponin concentrations can be used to stratify patients for benefit from treatment with tirofiban. \n METHODS We enrolled 2222 patients of the Platelet Receptor Inhibition in Ischemic Syndrome Management study with coronary artery disease and who had had chest pain in the previous 24 h. All patients received aspirin and were randomly assigned treatment with tirofiban or heparin. We took baseline measurements of troponin I and troponin T. We recorded death, myocardial infarction, or recurrent ischaemia after 48 h infusion treatment and at 7 days and 30 days. \n FINDINGS 629 (28.3%) patients had troponin I concentrations higher than the diagnostic threshold of 1.0 microg/L and 644 (29.0%) troponin T concentrations higher than 0.1 microg/L. 30-day event rates (death, myocardial infarction) were 13.0% for troponin-I-positive patients compared with 4.9% for troponin-I-negative patients (p<0.0001), and 13.7% compared wth 3.5% for troponin T (p<0.001). At 30 days, in troponin-I-positive patients, tirofiban had lowered the risk of death (adjusted hazard ratio 0.25 [95% CI 0.09-0.68], p=0.004) and myocardial infarction (0.37 [0.16-0.84], p=0.01). This benefit was seen in medically managed patients (0.30 [0.10-0.84], p=0.004) and those undergoing revascularisation (0.37 [0.15-0.93] p=0.02) after 48 h infusion treatment. By contrast, no treatment effect was seen for troponin-I-negative patients. Similar benefits were seen for troponin-T-positive patients. \n INTERPRETATION Troponin I and troponin T reliably identified high-risk patients with acute coronary syndromes, managed medically and by revascularisation, who would benefit from tirofiban.", "title": "Troponin concentrations for stratification of patients with acute coronary syndromes in relation to therapeutic efficacy of tirofiban. PRISM Study Investigators. Platelet Receptor Inhibition in Ischemic Syndrome Management." }, { "docid": "308862", "text": "BACKGROUND The combination of radiotherapy plus long-term medical suppression of androgens (> or = 2 years) improves overall survival in patients with locally advanced prostate cancer. We compared the use of radiotherapy plus short-term androgen suppression with the use of radiotherapy plus long-term androgen suppression in the treatment of locally advanced prostate cancer. \n METHODS We randomly assigned patients with locally advanced prostate cancer who had received external-beam radiotherapy plus 6 months of androgen suppression to two groups, one to receive no further treatment (short-term suppression) and the other to receive 2.5 years of further treatment with a luteinizing hormone-releasing hormone agonist (long-term suppression). An outcome of noninferiority of short-term androgen suppression as compared with long-term suppression required a hazard ratio of more than 1.35 for overall survival, with a one-sided alpha level of 0.05. An interim analysis showed futility, and the results are presented with an adjusted one-sided alpha level of 0.0429. \n RESULTS A total of 1113 men were registered, of whom 970 were randomly assigned, 483 to short-term suppression and 487 to long-term suppression. After a median follow-up of 6.4 years, 132 patients in the short-term group and 98 in the long-term group had died; the number of deaths due to prostate cancer was 47 in the short-term group and 29 in the long-term group. The 5-year overall mortality for short-term and long-term suppression was 19.0% and 15.2%, respectively; the observed hazard ratio was 1.42 (upper 95.71% confidence limit, 1.79; P=0.65 for noninferiority). Adverse events in both groups included fatigue, diminished sexual function, and hot flushes. \n CONCLUSIONS The combination of radiotherapy plus 6 months of androgen suppression provides inferior survival as compared with radiotherapy plus 3 years of androgen suppression in the treatment of locally advanced prostate cancer. (ClinicalTrials.gov number, NCT00003026.)", "title": "Duration of androgen suppression in the treatment of prostate cancer." }, { "docid": "30981192", "text": "Lowering low-density lipoprotein-cholesterol (LDL-C) is the primary target in the management of dyslipidemia in patients at high risk of cardiovascular disease. However, patients who have achieved LDL-C levels below the currently recommended targets may still experience cardiovascular events. This may result, in part, from elevated triglyceride (TG) levels and low levels of high-density lipoprotein-cholesterol (HDL-C). Low HDL-C and high TG levels are common and are recognized as independent risk factors for cardiovascular morbidity and mortality. Furthermore, atherogenic dyslipidemia, characterized by low levels of HDL-C, high TG, and small, dense LDL particles, is a typical phenotype of dyslipidemia in subjects with insulin resistance and metabolic syndrome. Therefore, to reduce further the risk of coronary heart disease (CHD), raising HDL-C and lowering TG may be the secondary therapeutic target for patients who achieve LDL-C levels below the currently recommended targets but are still at risk of CHD. However, whether increasing HDL-C levels alone reduces CHD has not yet been confirmed in large randomized clinical trials, and whether functional HDL is more important than HDL-C in reducing CHD remains controversial. Large CHD endpoint trials that include many patients with diabetes are underway to compare combination treatments with statin and niacin, fibrates, or cholesteryl ester transfer protein inhibitors with statin alone treatments. In this review, we discuss the rationale and importance of increasing HDL-C levels with and without lowering TG levels in the treatment and prevention of cardiovascular events.", "title": "How to control residual cardiovascular risk despite statin treatment: focusing on HDL-cholesterol." }, { "docid": "27054878", "text": "BACKGROUND Preoperative C-reactive protein (CRP) levels more than 10 mg/l have been shown to be associated with increased morbidity and mortality after cardiac surgery. We examine the value of preoperative CRP levels less than 10 mg/l for predicting long-term, all-cause mortality and hospital length of stay in surgical patients undergoing primary, nonemergent coronary artery bypass graft-only surgery. \n METHODS We examined the association between preoperative CRP levels stratified into four categories (< 1, 1-3, 3-10, and > 10 mg/l), and 7-yr all-cause mortality and hospital length of stay in 914 prospectively enrolled primary, nonemergent coronary artery bypass graft-only surgical patients using a proportional hazards regression model. \n RESULTS Eighty-seven patients (9.5%) died during a mean follow-up period of 4.8 +/- 1.5 yr. After proportional hazards adjustment, the 3-10 and > 10 mg/l preoperative CRP groups were associated with long-term, all-cause mortality (hazards ratios [95% CI]: 2.50 [1.22-5.16], P = 0.01 and 2.66 [1.21-5.80], P = 0.02, respectively) and extended hospital length of stay (1.32 [1.07-1.63], P < 0.001 and 1.27 [1.02-1.62], P = 0.001, respectively). \n CONCLUSION We demonstrate that preoperative CRP levels as low as 3 mg/l are associated with increased long-term mortality and extended hospital length of stay in relatively lower-acuity patients undergoing primary, nonemergent coronary artery bypass graft-only surgery. These important findings may allow for more objective risk stratification of patients who present for uncomplicated surgical coronary revascularization.", "title": "Preoperative C-reactive protein predicts long-term mortality and hospital length of stay after primary, nonemergent coronary artery bypass grafting." } ]

[ { "docid": "4394817", "text": "In the established model of mammalian cell cycle control, the retinoblastoma protein (Rb) functions to restrict cells from entering S phase by binding and sequestering E2f activators (E2f1, E2f2 and E2f3), which are invariably portrayed as the ultimate effectors of a transcriptional program that commit cells to enter and progress through S phase. Using a panel of tissue-specific cre-transgenic mice and conditional E2f alleles we examined the effects of E2f1, E2f2 and E2f3 triple deficiency in murine embryonic stem cells, embryos and small intestines. We show that in normal dividing progenitor cells E2f1-3 function as transcriptional activators, but contrary to the current view, are dispensable for cell division and instead are necessary for cell survival. In differentiating cells E2f1-3 function in a complex with Rb as repressors to silence E2f targets and facilitate exit from the cell cycle. The inactivation of Rb in differentiating cells resulted in a switch of E2f1-3 from repressors to activators, leading to the superactivation of E2f responsive targets and ectopic cell divisions. Loss of E2f1-3 completely suppressed these phenotypes caused by Rb deficiency. This work contextualizes the activator versus repressor functions of E2f1-3 in vivo, revealing distinct roles in dividing versus differentiating cells and in normal versus cancer-like cell cycles.", "title": "E2F1-3 Switch from Activators in Progenitor Cells to Repressors in Differentiating Cells" } ]

[ { "docid": "9641846", "text": "The ability of progenitor cells to exit the cell cycle is essential for proper embryonic development and homeostasis, but the mechanisms governing cell cycle exit are still not fully understood. Here, we tested the requirement for the retinoblastoma (Rb) protein and its family members p107 and p130 in G0/G1 arrest and differentiation in mammalian cells. We found that Rb family triple knockout (TKO) mouse embryos survive until days 9-11 of gestation. Strikingly, some TKO cells, including in epithelial and neural lineages, are able to exit the cell cycle in G0/G1 and differentiate in teratomas and in culture. This ability of TKO cells to arrest in G0/G1 is associated with the repression of key E2F target genes. Thus, G1 arrest is not always dependent on Rb family members, which illustrates the robustness of cell cycle regulatory networks during differentiation and allows for the identification of candidate pathways to inhibit the expansion of cancer cells with mutations in the Rb pathway.", "title": "G1 arrest and differentiation can occur independently of Rb family function" }, { "docid": "7688110", "text": "The E2F family of transcription factors are essential for the regulation of genes required for appropriate progression through the cell cycle. Five members of the E2F family have been previously reported, namely E2F1-5. All five are key elements in transcriptional regulation of essential genes, and they can be divided into two functional groups, those that induce S-phase progression when overexpressed in quiescent cells (E2Fs 1–3), and those that do not (E2Fs 4–5). Here, we describe the identification of a novel member of this family, which we refer to as E2F-6. E2F-6 shares significant homology with E2Fs 1–5, especially within the DNA binding, heterodimerization and marked box domains. Unlike E2Fs 1–5, E2F-6 lacks a transactivation and a pocket protein binding domain, hence, forms a unique third group within the E2F family. E2F-6 is a nuclear protein that can form heterodimers with the DP proteins (both DP-1 and DP-2) in vitro and in vivo. Our results show that the complex formed between E2F-6 and the DP proteins, possesses high DNA binding activity, displaying a preference for a TTTCCCGC E2F recognition site, which is slightly different to the E2F consensus site derived from the E2 promoter (TTTCGCGC). In contrast to the other members of the E2F family, ectopic expression of E2F-6 inhibits transcription from promoters possessing E2F recognition sites rather than activating transcription. In addition, overexpression of E2F-6 suppresses the transactivational effects of co-expression of E2F-1 and DP-1. The inhibitory effect of E2F-6 is dependent on its DNA binding activity and its ability to form heterodimers with the DPs. Interestingly, ectopic expression of E2F-6 leads to accumulation of cells in S-phase. Our data suggest that E2F-6 expression delays the exit from S-phase rather than inducing S-phase, which further emphasizes the functional difference between E2F-6 and the previously known E2F family members.", "title": "E2F-6: a novel member of the E2F family is an inhibitor of E2F-dependent transcription" }, { "docid": "30580263", "text": "The cell-positional incidence of both spontaneous and damage-induced apoptosis of epithelial cells was assessed in longitudinal sections of the crypts of small intestine and colon of BDF1 mice. This was compared, using immunohistochemistry, with the pattern of expression of bcl-2, a suppressor of apoptosis. In the small intestine, apoptosis was maximal around cell position 4 from the base of the crypt; this closely corresponds to the position considered to contain the stem cells. In the colon, however, apoptosis was not confined to the area considered to harbour the stem cells (position 1 and 2). Instead, apoptosis was attenuated and distributed along the length of the crypt. Some cells at the base of murine colonic crypts expressed bcl-2 protein, whereas bcl-2 was absent in the crypts of the small intestine. Most pertinently, bcl-2 was absent from small intestinal crypt cells at positions 4-5 (the stem cell region). The importance of the expression of bcl-2 to the attenuation of apoptosis in stem cells was confirmed by analysis of the levels of both spontaneous and induced apoptosis in homozygously bcl-2 null C57BL/6 mice: in colonic crypts the level of spontaneous apoptosis rose significantly, and selectively at the base of the crypt, in comparison with crypts from wild-type animals. In contrast, there was no rise in spontaneous apoptosis in the small intestinal crypts from the bcl-2 null animals. Analysis of sections of human colon and small intestine also showed that expression of bcl-2 was confined to the base of the colonic crypt. The attenuation of apoptosis by bcl-2 in the region of the stem cells of the colonic crypts may dispose these to neoplastic transformation. Indeed, analysis of human carcinomas revealed expression of bcl-2, which in some samples was reciprocal with the expression of p53.", "title": "Differential expression of bcl-2 in intestinal epithelia. Correlation with attenuation of apoptosis in colonic crypts and the incidence of colonic neoplasia." }, { "docid": "502591", "text": "E2F proteins can either activate or repress transcription. Following mitogenic stimulation, repressive E2F4-p130-histone deacetylase complexes dissociate from, while activating species (E2F1, -2, and -3) associate with, target promoters. Histones H3 and H4 simultaneously become hyperacetylated, but it remains unclear whether this is a prerequisite or a consequence of E2F binding. Here, we show that activating E2F species are required for hyperacetylation of target chromatin in human cells. Overexpression of a dominant-negative (DN) E2F1 mutant in serum-stimulated T98G cells blocked all E2F binding, H4 acetylation, and, albeit partially, H3 acetylation. Target gene activation and S-phase entry were also blocked by DN E2F1. Conversely, ectopic activation of E2F1 rapidly induced H3 and H4 acetylation, demonstrating a direct role for E2F in these events. E2F1 was previously shown to bind the histone acetyltransferases (HATs) p300/CBP and PCAF/GCN5. In our hands, ectopically expressed E2F1 also bound the unrelated HAT Tip60 and induced recruitment of five subunits of the Tip60 complex (Tip60, TRRAP, p400, Tip48, and Tip49) to target promoters in vivo. Moreover, E2F-dependent recruitment of Tip60 to chromatin occurred in late G(1) following serum stimulation. We speculate that the activities of multiple HAT complexes account for E2F-dependent acetylation, transcription, and S-phase entry.", "title": "E2F-dependent histone acetylation and recruitment of the Tip60 acetyltransferase complex to chromatin in late G1." }, { "docid": "29423324", "text": "Human group 1 ILCs consist of at least three phenotypically distinct subsets, including NK cells, CD127(+) ILC1, and intraepithelial CD103(+) ILC1. In inflamed intestinal tissues from Crohn's disease patients, numbers of CD127(+) ILC1 increased at the cost of ILC3. Here we found that differentiation of ILC3 to CD127(+) ILC1 is reversible in vitro and in vivo. CD127(+) ILC1 differentiated to ILC3 in the presence of interleukin-2 (IL-2), IL-23, and IL-1β dependent on the transcription factor RORγt, and this process was enhanced in the presence of retinoic acid. Furthermore, we observed in resection specimen from Crohn's disease patients a higher proportion of CD14(+) dendritic cells (DC), which in vitro promoted polarization from ILC3 to CD127(+) ILC1. In contrast, CD14(-) DCs promoted differentiation from CD127(+) ILC1 toward ILC3. These observations suggest that environmental cues determine the composition, function, and phenotype of CD127(+) ILC1 and ILC3 in the gut.", "title": "Interleukin-12 and -23 Control Plasticity of CD127(+) Group 1 and Group 3 Innate Lymphoid Cells in the Intestinal Lamina Propria." }, { "docid": "40096222", "text": "Mice lacking junctional adhesion molecule A (JAM-A, encoded by F11r) exhibit enhanced intestinal epithelial permeability, bacterial translocation, and elevated colonic lymphocyte numbers, yet do not develop colitis. To investigate the contribution of adaptive immune compensation in response to increased intestinal epithelial permeability, we examined the susceptibility of F11r(-/-)Rag1(-/-) mice to acute colitis. Although negligible contributions of adaptive immunity in F11r(+/+)Rag1(-/-) mice were observed, F11r(-/-)Rag1(-/-) mice exhibited increased microflora-dependent colitis. Elimination of T cell subsets and cytokine analyses revealed a protective role for TGF-β-producing CD4(+) T cells in F11r(-/-) mice. Additionally, loss of JAM-A resulted in elevated mucosal and serum IgA that was dependent upon CD4(+) T cells and TGF-β. Absence of IgA in F11r(+/+)Igha(-/-) mice did not affect disease, whereas F11r(-/-)Igha(-/-) mice displayed markedly increased susceptibility to acute injury-induced colitis. These data establish a role for adaptive immune-mediated protection from acute colitis under conditions of intestinal epithelial barrier compromise.", "title": "Compromised intestinal epithelial barrier induces adaptive immune compensation that protects from colitis." }, { "docid": "24624992", "text": "In a cell-type- and stimulus-dependent fashion, the early response gene immediate early gene X-1 (IEX-1) is involved in growth control and modulation of apoptosis. The present study demonstrates that, in the two acute promyelocytic leukemia (APL) cell lines NB4 and KG1, exhibiting distinct responsiveness to retinoic acids (RAs), IEX-1 expression is rapidly (30–60 min) induced by all-trans- or cis-RA and independently of other signal transduction mediators, such as TNFα, NF-κB or MAP kinases. In NB4 cells (expressing PML–RARα), this increase is transient and completely reversible, along with a cell cycle arrest, ongoing differentiation and lower sensitivity to anti-cancer-drug-induced apoptosis. In contrast, the RA-induced IEX-1 expression in KG1 cells (expressing PLZF–RARα) persists over days, along with continued cell cycle progression and increased apoptotic sensitivity. Furthermore, two functional RA-response elements in the IEX-1 promoter were identified by gel shift and luciferase reporter gene assays. IEX-1 might be a rather unique transcriptional target of the two X–RARα fusion receptors exhibiting distinct responsiveness to RAs. Following a different time course of direct transcriptional induction by PML–RARα and PLZF–RARα in NB4 and KG1 cells, respectively, IEX-1 expression may be involved in the modified actions of these receptors and the distinct phenotypes of APL cells.", "title": "The expression of immediate early gene X-1 (IEX-1) is differentially induced by retinoic acids in NB4 and KG1 cells: possible implication in the distinct phenotype of retinoic acid-responsive and -resistant leukemic cells" }, { "docid": "18956141", "text": "Intestinal epithelial cells (IECs) regulate gut immune homeostasis, and impaired epithelial responses are implicated in the pathogenesis of inflammatory bowel diseases (IBD). IEC-specific ablation of nuclear factor κB (NF-κB) essential modulator (NEMO) caused Paneth cell apoptosis and impaired antimicrobial factor expression in the ileum, as well as colonocyte apoptosis and microbiota-driven chronic inflammation in the colon. Combined RelA, c-Rel, and RelB deficiency in IECs caused Paneth cell apoptosis but not colitis, suggesting that NEMO prevents colon inflammation by NF-κB-independent functions. Inhibition of receptor-interacting protein kinase 1 (RIPK1) kinase activity or combined deficiency of Fas-associated via death domain protein (FADD) and RIPK3 prevented epithelial cell death, Paneth cell loss, and colitis development in mice with epithelial NEMO deficiency. Therefore, NEMO prevents intestinal inflammation by inhibiting RIPK1 kinase activity-mediated IEC death, suggesting that RIPK1 inhibitors could be effective in the treatment of colitis in patients with NEMO mutations and possibly in IBD.", "title": "NEMO Prevents RIP Kinase 1-Mediated Epithelial Cell Death and Chronic Intestinal Inflammation by NF-κB-Dependent and -Independent Functions" }, { "docid": "10218447", "text": "Isorhamnetin is one member of flavonoid components which has been used in the treatment of heart disease. Recently the in vitro anti-cancer effect of isorhamnetin on human esophageal squamous carcinoma cell line Eca-109 was investigated in our lab. When Eca-109 cells were in vitro exposed to the graded doses of isorhamnetin (0-80 microg/ml) for 48 h, respectively, isorhamnetin exhibited cytostatic effect on the treated cells, with an IC(50) of 40+/-0.08 microg/ml as estimated by MTT assay. Inhibition on proliferation by isorhamnetin was detected by trypan blue exclusion assay, clone formation test, immunocytochemical assay of PCNA and (3)H-thymidine uptake analysis. Cell cycle distribution was measured by FCM. It was found that the viability of Eca-109 cells was significantly hampered by isorhamnetin. Compared with the negative control group, the treated group which was exposed to isorhamnetin had increased population in G(0)/G(1) phase from 74.6 to 84 while had a significant reduction in G(2)/M phase from 11.9 to 5.8. In addition to its cytostatic effect, isorhamnetin also showed stimulatory effect on apoptosis. Typical apoptotic morphology such as condensation and fragmentation of nuclei and blebbing membrane of the apoptotic cells could be observed through transmission electron microscope. Moreover, the sharp increase in apoptosis rate between the control and treated group were detected by FCM from 6.3 to 16.3. To explore the possible molecular mechanisms that underlie the growth inhibition and apoptosis stimulatory effects of isorhamnetin, the expressions of six proliferation- and death-related genes were detected by FCM. Expressions of bcl-2, c-myc and H-ras were downregulated whereas Bax, c-fos and p53 were upregulated. However, the in vivo experiments were required to further confirm the anti-cancer effects of isorhamnetin. In conclusion, isorhamnetin appears to be a potent drug against esophageal cancer due to its in vitro potential to not only inhibit proliferation but also induce apoptosis of Eca-109 cells.", "title": "The flavonoid component isorhamnetin in vitro inhibits proliferation and induces apoptosis in Eca-109 cells." }, { "docid": "41710132", "text": "The tumor suppressor PML (promyelocytic leukemia protein) regulates cellular senescence and terminal differentiation, two processes that implicate a permanent exit from the cell cycle. Here, we show that the mechanism by which PML induces a permanent cell cycle exit and activates p53 and senescence involves a recruitment of E2F transcription factors bound to their promoters and the retinoblastoma (Rb) proteins to PML nuclear bodies enriched in heterochromatin proteins and protein phosphatase 1α. Blocking the functions of the Rb protein family or adding back E2Fs to PML-expressing cells can rescue their defects in E2F-dependent gene expression and cell proliferation, inhibiting the senescent phenotype. In benign prostatic hyperplasia, a neoplastic disease that displays features of senescence, PML was found to be up-regulated and forming nuclear bodies. In contrast, PML bodies were rarely visualized in prostate cancers. The newly defined PML/Rb/E2F pathway may help to distinguish benign tumors from cancers, and suggest E2F target genes as potential targets to induce senescence in human tumors.", "title": "Regulation of E2Fs and senescence by PML nuclear bodies." }, { "docid": "42782688", "text": "BACKGROUND Alkaline sphingomyelinase, an enzyme found exclusively in bile and the intestinal brush border, hydrolyzes sphingomyelin into ceramide, sphingosine and sphingosine-1-phosphate, thereby inducing epithelial apoptosis. Reduced levels of alkaline sphingomyelinase have been found in premalignant and malignant intestinal epithelia and in ulcerative colitis tissue. Probiotic bacteria can be a source of sphingomyelinase. \n OBJECTIVE To determine the effect of VSL#3 probiotic therapy on mucosal levels of alkaline sphingomyelinase, both in a mouse model of colitis and in patients with ulcerative colitis. \n METHODS Interleukin-10 gene-deficient (IL10KO) and wild type control mice were treated with VSL#3 (10(9) colony-forming units per day) for three weeks, after which alkaline sphingomyelinase activity was measured in ileal and colonic tissue. As well, 15 patients with ulcerative colitis were treated with VSL#3 (900 billion bacteria two times per day for five weeks). Alkaline sphingomyelinase activity was measured through biopsies and comparison of ulcerative colitis disease activity index scores obtained before and after treatment. \n RESULTS Lowered alkaline sphingomyelinase levels were seen in the colon (P=0.02) and ileum (P=0.04) of IL10KO mice, as compared with controls. Treatment of these mice with VSL#3 resulted in upregulation of mucosal alkaline sphingomyelinase activity in both the colon (P=0.04) and the ileum (P=0.01). VSL#3 treatment of human patients who had ulcerative colitis decreased mean (+/- SEM) ulcerative colitis disease activity index scores from 5.3+/-1.8946 to 0.70+/-0.34 (P=0.02) and increased mucosal alkaline sphingomyelinase activity. \n CONCLUSION Mucosal alkaline sphingomyelinase activity is reduced in the intestine of IL10KO mice with colitis and in humans with ulcerative colitis. VSL#3 probiotic therapy upregulates mucosal alkaline sphingomyelinase activity.", "title": "VSL#3 probiotic upregulates intestinal mucosal alkaline sphingomyelinase and reduces inflammation." }, { "docid": "13007205", "text": "Stromal fibroblasts can contribute to tumor invasion through the release of matrix metalloproteinases (MMPs). Population studies have suggested that single nucleotide polymorphisms (SNPs) in MMP genes influence levels of expression and may be associated with breast cancer risk and with disease progression. This study directly examined the impact of MMP SNP genotype on the ability of host fibroblasts to promote tumor cell invasion. Primary breast fibroblasts were isolated from patients with (n = 13) or without (n = 19) breast cancer, and their ability to promote breast cancer cell invasion was measured in in vitro invasion assays. Fibroblast invasion-promoting capacity (IPC) was analyzed in relation to donor type (tumor or non-tumor patient), MMP-1, MMP-3, and MMP-9 SNP genotype and MMP activity using independent samples t test and analysis of variance. All statistical tests were two-sided. Tumor-derived fibroblasts promoted higher levels of invasion than normal fibroblasts (p = 0.041). When IPC was related to genotype, higher levels of IPC were generated by tumor fibroblasts with the high-expressing MMP-3 5A/5A genotype compared with the 5A/6A and 6A/6A genotypes (p = 0.05 and 0.07, respectively), and this was associated with enhanced MMP-3 release. The functional importance of MMP-3 was demonstrated by enhanced invasion in the presence of recombinant MMP-3, whereas reduction occurred in the presence of a specific MMP-3 inhibitor. An inverse relationship was demonstrated between fibroblast IPC and the high-expressing MMP-1 genotype (p = 0.031), but no relationship was seen with MMP-9 SNP status. In contrast, normal fibroblasts showed no variation in IPC in relation to MMP genotype, with MMP-3 5A/5A fibroblasts exhibiting significantly lower levels of IPC than their tumor-derived counterparts (p = 0.04). This study has shown that tumor-derived fibroblasts exhibit higher levels of IPC than normal fibroblasts and that the MMP-3 5A/5A genotype contributes to this through enhanced MMP-3 release. Despite a high-expressing genotype, normal fibroblasts do not exhibit higher IPC or enhanced MMP release. This suggests that more complex changes occur in tumor-derived fibroblasts, enabling full expression of the MMP SNP genotype and these possibly are epigenetic in nature. The results do suggest that, in women with breast cancer, a high-expressing MMP-3 genotype may promote tumor progression more effectively.", "title": "Intrinsic genetic characteristics determine tumor-modifying capacity of fibroblasts: matrix metalloproteinase-3 5A/5A genotype enhances breast cancer cell invasion" }, { "docid": "5254463", "text": "Colorectal cancer is one of the major causes of cancer-related deaths. To gain further insights into the mechanisms underlying its development, we investigated the role of Wip1 phosphatase, which is highly expressed in intestinal stem cells, in the mouse model of APC(Min)-driven polyposis. We found that Wip1 removal increased the life span of APC(Min) mice through a significant suppression of polyp formation. This protection was dependent on the p53 tumor suppressor, which plays a putative role in the regulation of apoptosis of intestinal stem cells. Activation of apoptosis in stem cells of Wip1-deficient mice, but not wild-type APC(Min) mice, increased when the Wnt pathway was constitutively activated. We propose, therefore, that the Wip1 phosphatase regulates homeostasis of intestinal stem cells. In turn, Wip1 loss suppresses APC(Min)-driven polyposis by lowering the threshold for p53-dependent apoptosis of stem cells, thus preventing their conversion into tumor-initiating stem cells.", "title": "Wip1 phosphatase regulates p53-dependent apoptosis of stem cells and tumorigenesis in the mouse intestine." }, { "docid": "28697248", "text": "The E2F transcription factors have emerged as critical apoptotic effectors. Herein we report that the E2F family member E2F3a can be induced by DNA damage through transcriptional and posttranslational mechanisms. We demonstrate that the posttranslational induction of human E2F3a is dependent on the checkpoint kinases. Moreover, we show that human E2F3a is a substrate for the checkpoint kinases (chk kinases) and that mutation of the chk phosphorylation site eliminates the DNA damage inducibility of the protein. Furthermore, we demonstrate that E2F1 and E2F2 are transcriptionally induced by DNA damage in an E2f3-dependent manner. Finally, using both in vitro and in vivo approaches, we establish that E2f3 is required for DNA damage-induced apoptosis. Thus, our data reveal the novel ability of E2f3 to function as a master regulator of the DNA damage response.", "title": "E2F3 is a mediator of DNA damage-induced apoptosis." }, { "docid": "41646286", "text": "Effects of folate deficiency on the rate of apoptosis in human cytotrophoblastic cells has been investigated. Apoptosis was determined in cytotrophoblastic cells after culture in 1. control medium, 2. folate-free medium and 3. folate-free medium plus 10% fetal calf serum. Apoptosis rates in cells cultured in mediums 2 and 3 were significantly higher than those cultured in the control medium (P<0.02 and P<0.03, respectively). In conclusion, human cytotrophoblastic cells show a significantly increased rate of apoptosis in vitro after culture in a folate-free medium. Possible explanations for the association between folate deficiency and pregnancy complications are suggested.", "title": "Folate affects apoptosis in human trophoblastic cells." }, { "docid": "42873134", "text": "Type 1 and type 2 diabetes are characterized by progressive beta-cell failure. Apoptosis is probably the main form of beta-cell death in both forms of the disease. It has been suggested that the mechanisms leading to nutrient- and cytokine-induced beta-cell death in type 2 and type 1 diabetes, respectively, share the activation of a final common pathway involving interleukin (IL)-1beta, nuclear factor (NF)-kappaB, and Fas. We review herein the similarities and differences between the mechanisms of beta-cell death in type 1 and type 2 diabetes. In the insulitis lesion in type 1 diabetes, invading immune cells produce cytokines, such as IL-1beta, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma. IL-1beta and/or TNF-alpha plus IFN-gamma induce beta-cell apoptosis via the activation of beta-cell gene networks under the control of the transcription factors NF-kappaB and STAT-1. NF-kappaB activation leads to production of nitric oxide (NO) and chemokines and depletion of endoplasmic reticulum (ER) calcium. The execution of beta-cell death occurs through activation of mitogen-activated protein kinases, via triggering of ER stress and by the release of mitochondrial death signals. Chronic exposure to elevated levels of glucose and free fatty acids (FFAs) causes beta-cell dysfunction and may induce beta-cell apoptosis in type 2 diabetes. Exposure to high glucose has dual effects, triggering initially \"glucose hypersensitization\" and later apoptosis, via different mechanisms. High glucose, however, does not induce or activate IL-1beta, NF-kappaB, or inducible nitric oxide synthase in rat or human beta-cells in vitro or in vivo in Psammomys obesus. FFAs may cause beta-cell apoptosis via ER stress, which is NF-kappaB and NO independent. Thus, cytokines and nutrients trigger beta-cell death by fundamentally different mechanisms, namely an NF-kappaB-dependent mechanism that culminates in caspase-3 activation for cytokines and an NF-kappaB-independent mechanism for nutrients. This argues against a unifying hypothesis for the mechanisms of beta-cell death in type 1 and type 2 diabetes and suggests that different approaches will be required to prevent beta-cell death in type 1 and type 2 diabetes.", "title": "Mechanisms of pancreatic beta-cell death in type 1 and type 2 diabetes: many differences, few similarities." }, { "docid": "4459491", "text": "Alzheimer’s disease is the most common form of dementia, characterized by two pathological hallmarks: amyloid-β plaques and neurofibrillary tangles. The amyloid hypothesis of Alzheimer’s disease posits that the excessive accumulation of amyloid-β peptide leads to neurofibrillary tangles composed of aggregated hyperphosphorylated tau. However, to date, no single disease model has serially linked these two pathological events using human neuronal cells. Mouse models with familial Alzheimer’s disease (FAD) mutations exhibit amyloid-β-induced synaptic and memory deficits but they do not fully recapitulate other key pathological events of Alzheimer’s disease, including distinct neurofibrillary tangle pathology. Human neurons derived from Alzheimer’s disease patients have shown elevated levels of toxic amyloid-β species and phosphorylated tau but did not demonstrate amyloid-β plaques or neurofibrillary tangles. Here we report that FAD mutations in β-amyloid precursor protein and presenilin 1 are able to induce robust extracellular deposition of amyloid-β, including amyloid-β plaques, in a human neural stem-cell-derived three-dimensional (3D) culture system. More importantly, the 3D-differentiated neuronal cells expressing FAD mutations exhibited high levels of detergent-resistant, silver-positive aggregates of phosphorylated tau in the soma and neurites, as well as filamentous tau, as detected by immunoelectron microscopy. Inhibition of amyloid-β generation with β- or γ-secretase inhibitors not only decreased amyloid-β pathology, but also attenuated tauopathy. We also found that glycogen synthase kinase 3 (GSK3) regulated amyloid-β-mediated tau phosphorylation. We have successfully recapitulated amyloid-β and tau pathology in a single 3D human neural cell culture system. Our unique strategy for recapitulating Alzheimer’s disease pathology in a 3D neural cell culture model should also serve to facilitate the development of more precise human neural cell models of other neurodegenerative disorders.", "title": "A three-dimensional human neural cell culture model of Alzheimer’s disease" }, { "docid": "9831859", "text": "Pancreatic stellate cells (PSC) produce the stromal reaction in pancreatic cancer, but their role in cancer progression is not fully elucidated. We examined the influence of PSCs on pancreatic cancer growth using (a) an orthotopic model of pancreatic cancer and (b) cultured human PSCs (hPSC) and human pancreatic cancer cell lines MiaPaCa-2 and Panc-1. Athymic mice received an intrapancreatic injection of saline, hPSCs, MiaPaCa-2 cells, or hPSCs + MiaPaCa-2. After 7 weeks, tumor size, metastases, and tumor histology were assessed. In vitro studies assessed the effect of cancer cell secretions on PSC migration and the effect of hPSC secretions on cancer cell proliferation, apoptosis, and migration. Possible mediators of the effects of hPSC secretions on cancer cell proliferation were examined using neutralizing antibodies. Compared with mice receiving MiaPaCa-2 cells alone, mice injected with hPSCs + MiaPaCa-2 exhibited (a) increased tumor size and regional and distant metastasis, (b) fibrotic bands (desmoplasia) containing activated PSCs within tumors, and (c) increased tumor cell numbers. In vitro studies showed that, in the presence of pancreatic cancer cells, PSC migration was significantly increased. Furthermore, hPSC secretions induced the proliferation and migration, but inhibited the apoptosis, of MiaPaCa-2 and Panc-1 cells. The proliferative effect of hPSC secretions on pancreatic cancer cells was inhibited in the presence of neutralizing antibody to platelet-derived growth factor. Our studies indicate a significant interaction between pancreatic cancer cells and stromal cells (PSCs) and imply that pancreatic cancer cells recruit stromal cells to establish an environment that promotes cancer progression.", "title": "Pancreatic stellate cells: partners in crime with pancreatic cancer cells." }, { "docid": "13244602", "text": "CD133+ populations of human glioblastoma multiforme (GBM) cells are reportedly enriched for tumor stem cells (TSCs) or tumor-initiating cells (TICs). Approximately 40% of freshly isolated GBM specimens, however, do not contain CD133+ tumor cells, raising the possibility that CD133 may not be a universal enrichment marker for GBM TSCs/TICs. Here we demonstrate that stage-specific embryonic antigen 1(SSEA-1/LeX)+ GBM cells fulfill the functional criteria for TSC/TIC, since (1) SSEA-1+ cells are highly tumorigenic in vivo, unlike SSEA-1- cells; (2) SSEA-1+ cells can give rise to both SSEA-1+ and SSEA-1- cells, thereby establishing a cellular hierarchy; and (3) SSEA-1+ cells have self-renewal and multilineage differentiation potentials. A distinct subpopulation of SSEA-1+ cells was present in all but one of the primary GBMs examined (n = 24), and most CD133+ tumor cells were also SSEA-1+, suggesting that SSEA-1 may be a general TSC/TIC enrichment marker in human GBMs.", "title": "SSEA-1 is an enrichment marker for tumor-initiating cells in human glioblastoma." } ]