296 research outputs found
IFNB/interferon-β regulates autophagy via a MIR1-TBC1D15-RAB7 pathway.
Loss of IFNB/interferon-β in mice causes a Parkinson disease-like phenotype where many features, including SNCA/α-synuclein and MAPT/tau accumulation, can be attributed to a late-stage block in autophagic flux. Recently, we identified a mechanism that can explain this phenotype. We found that IFNB induces expression of Mir1, a microRNA that can reduce the levels of TBC1D15, a RAB GTPase-activating protein. Induction of this pathway decreases RAB7 activity and thereby stimulates macroautophagy/autophagy. The relevance of these key players is deeply conserved from humans to Caenorhabditis elegans, highlighting the importance of this ancient autophagy regulatory pathway.UK Dementia Research Institute at the University of Cambridge
(funded by the MRC, Alzheimer’s Research UK and the Alzheimer’s Society), the National
Institute for Health Research Cambridge Biomedical Research Centre, the Wellcome Trust
(095317/Z/11/Z), the Spoelberch Foundation and an anonymous donation to the Cambridge
Centre for Parkinson-Plus to D.C.R., NHMRC (Senior Research Fellowship GNT1137645
and Project Grant GNT1156481 to R.P.), veski Innovation Fellowship (VIF23 to R.P.), The
Danish Council for Independent Research (DFF - 6110-00461 to P.E.), Lundbeck
Foundation (R210-2015-3372 to P.E.), and Parkinsonforening in Denmark (to P.E.)
The ETS-5 transcription factor regulates activity states in Caenorhabditis elegans by controlling satiety
Animal behavior is shaped through interplay among genes, the environment, and previous experience. As in mammals, satiety signals induce quiescence in Caenorhabditis elegans. Here we report that the C. elegans transcription factor ETS-5, an ortholog of mammalian FEV/Pet1, controls satiety-induced quiescence. Nutritional status has a major influence on C. elegans behavior. When foraging, food availability controls behavioral state switching between active (roaming) and sedentary (dwelling) states; however, when provided with high-quality food, C. elegans become sated and enter quiescence. We show that ETS-5 acts to promote roaming and inhibit quiescence by setting the internal “satiety quotient” through fat regulation. Acting from the ASG and BAG sensory neurons, we show that ETS-5 functions in a complex network with serotonergic and neuropeptide signaling pathways to control food-regulated behavioral state switching. Taken together, our results identify a neuronal mechanism for controlling intestinal fat stores and organismal behavioral states in C. elegans, and establish a paradigm for the elucidation of obesity-relevant mechanisms
Employment status at time of first hospitalization for heart failure is associated with death and rehospitalization for heart failure
Background: Employment status at time of first heart failure (HF) hospitalization may be an indicator of both self-perceived and objective health status. In this study, we examined the association between employment status and the risk of all-cause mortality and recurrent HF hospitalization in a nationwide cohort of patients with HF.
Methods and Results: We identified all patients of working age (18-60 years) with a first HF hospitalisation in the period 1997-2015 in Denmark, categorized according to whether or not they were part of the workforce at time of the index admission. The primary outcome was death from any cause and the secondary outcome was readmission for HF. Cumulative incidence curves, binomial regression and Cox regression models were used to assess outcomes. Of 25571 patients with a first hospitalization for HF, 15428 (60%) were part of the workforce at baseline. Patients in the workforce were significantly younger (53 vs. 55 years) more likely to be male (75% vs 64%) and less likely to have diabetes (13% vs 22%) and chronic obstructive pulmonary disease (5% vs 10%), all p-values <0.001. Not being part of the workforce was associated with a significantly higher risk of death (HR: 1.59 [95% CI 1.50–1.68]) and rehospitalisation for HF (HR: 1.09 [95% CI 1.05–1.14]), in analyses adjusted for age, sex, comorbidities, education level, calendar time, duration of first HF hospitalization.
Conclusion: Not being part of the workforce at time of first HF hospitalization was independently associated with increased mortality and recurrent HF hospitalization
Brain Energy and Oxygen Metabolism: Emerging Role in Normal Function and Disease
Dynamic metabolic changes occurring in neurons are critically important in directing brain plasticity and cognitive function. In other tissue types, disruptions to metabolism and the resultant changes in cellular oxidative state, such as increased reactive oxygen species (ROS) or induction of hypoxia, are associated with cellular stress. In the brain however, where drastic metabolic shifts occur to support physiological processes, subsequent changes to cellular oxidative state and induction of transcriptional sensors of oxidative stress likely play a significant role in regulating physiological neuronal function. Understanding the role of metabolism and metabolically-regulated genes in neuronal function will be critical in elucidating how cognitive functions are disrupted in pathological conditions where neuronal metabolism is affected. Here, we discuss known mechanisms regulating neuronal metabolism as well as the role of hypoxia and oxidative stress during normal and disrupted neuronal function. We also summarize recent studies implicating a role for metabolism in regulating neuronal plasticity as an emerging neuroscience paradigm
Simple estimators of the intensity of seasonal occurrence
<p>Abstract</p> <p>Background</p> <p>Edwards's method is a widely used approach for fitting a sine curve to a time-series of monthly frequencies. From this fitted curve, estimates of the seasonal intensity of occurrence (i.e., peak-to-low ratio of the fitted curve) can be generated.</p> <p>Methods</p> <p>We discuss various approaches to the estimation of seasonal intensity assuming Edwards's periodic model, including maximum likelihood estimation (MLE), least squares, weighted least squares, and a new closed-form estimator based on a second-order moment statistic and non-transformed data. Through an extensive Monte Carlo simulation study, we compare the finite sample performance characteristics of the estimators discussed in this paper. Finally, all estimators and confidence interval procedures discussed are compared in a re-analysis of data on the seasonality of monocytic leukemia.</p> <p>Results</p> <p>We find that Edwards's estimator is substantially biased, particularly for small numbers of events and very large or small amounts of seasonality. For the common setting of rare events and moderate seasonality, the new estimator proposed in this paper yields less finite sample bias and better mean squared error than either the MLE or weighted least squares. For large studies and strong seasonality, MLE or weighted least squares appears to be the optimal analytic method among those considered.</p> <p>Conclusion</p> <p>Edwards's estimator of the seasonal relative risk can exhibit substantial finite sample bias. The alternative estimators considered in this paper should be preferred.</p
Rationale and design of Ferinject® Assessment in patients with IRon deficiency and chronic Heart Failure (FAIR-HF) study: a randomized, placebo-controlled study of intravenous iron supplementation in patients with and without anaemia
Iron deficiency (ID) and anaemia are common in patients with chronic heart failure (CHF). The presence of anaemia is associated with increased morbidity and mortality in CHF, and ID is a major reason for the development of anaemia. Preliminary studies using intravenous (i.v.) iron supplementation alone in patients with CHF and ID have shown improvements in symptom status. FAIR-HF (Clinical Trials.gov NCT00520780) was designed to determine the effect of i.v. iron repletion therapy using ferric carboxymaltose on self-reported patient global assessment (PGA) and New York Heart Association (NYHA) in patients with CHF and ID. This is a multi-centre, randomized, double-blind, placebo-controlled study recruiting ambulatory patients with symptomatic CHF with LVEF < 40% (NYHA II) or < 45% (NYHA III), ID [ferritin < 100 ng/mL or ferritin 100-300 ng/mL when transferrin saturation (TSAT) < 20%], and haemoglobin 9.5-13.5 g/dL. Patients were randomized in a 2:1 ratio to receive ferric carboxymaltose (Ferinject((R))) 200 mg iron i.v. or saline i.v. weekly until iron repletion (correction phase), then monthly until Week 24 (maintenance phase). Primary endpoints are (i) self-reported PGA at Week 24 and (ii) NYHA class at Week 24, adjusted for baseline NYHA class. This study will provide evidence on the efficacy and safety of iron repletion with ferric carboxymaltose in CHF patients with ID with and without anaemia
A methodological framework to distinguish spectrum effects from spectrum biases and to assess diagnostic and screening test accuracy for patient populations: Application to the Papanicolaou cervical cancer smear test
<p>Abstract</p> <p>Background</p> <p>A spectrum effect was defined as differences in the sensitivity or specificity of a diagnostic test according to the patient's characteristics or disease features. A spectrum effect can lead to a spectrum bias when subgroup variations in sensitivity or specificity also affect the likelihood ratios and thus post-test probabilities. We propose and illustrate a methodological framework to distinguish spectrum effects from spectrum biases.</p> <p>Methods</p> <p>Data were collected for 1781 women having had a cervical smear test and colposcopy followed by biopsy if abnormalities were detected (the reference standard). Logistic models were constructed to evaluate both the sensitivity and specificity, and the likelihood ratios, of the test and to identify factors independently affecting the test's characteristics.</p> <p>Results</p> <p>For both tests, human papillomavirus test, study setting and age affected sensitivity or specificity of the smear test (spectrum effect), but only human papillomavirus test and study setting modified the likelihood ratios (spectrum bias) for clinical reading, whereas only human papillomavirus test and age modified the likelihood ratios (spectrum bias) for "optimized" interpretation.</p> <p>Conclusion</p> <p>Fitting sensitivity, specificity and likelihood ratios simultaneously allows the identification of covariates that independently affect diagnostic or screening test results and distinguishes spectrum effect from spectrum bias. We recommend this approach for the development of new tests, and for reporting test accuracy for different patient populations.</p
A Single Gene Target of an ETS-Family Transcription Factor Determines Neuronal CO2-Chemosensitivity
Many animals possess neurons specialized for the detection of carbon dioxide (CO2), which acts as a cue to elicit behavioral responses and is also an internally generated product of respiration that regulates animal physiology. In many organisms how such neurons detect CO2 is poorly understood. We report here a mechanism that endows C. elegans neurons with the ability to detect CO2. The ETS-5 transcription factor is necessary for the specification of CO2-sensing BAG neurons. Expression of a single ETS-5 target gene, gcy-9, which encodes a receptor-type guanylate cyclase, is sufficient to bypass a requirement for ets-5 in CO2-detection and transforms neurons into CO2-sensing neurons. Because ETS-5 and GCY-9 are members of gene families that are conserved between nematodes and vertebrates, a similar mechanism might act in the specification of CO2-sensing neurons in other phyla
Food webs: reconciling the structure and function of biodiversity
The global biodiversity crisis concerns not only unprecedented loss of species within communities, but also related consequences for ecosystem function. Community ecology focuses on patterns of species richness and community composition, whereas ecosystem ecology focuses on fluxes of energy and materials. Food webs provide a quantitative framework to combine these approaches and unify the study of biodiversity and ecosystem function. We summarise the progression of food-web ecology and the challenges in using the food-web approach. We identify five areas of research where these advances can continue, and be applied to global challenges. Finally, we describe what data are needed in the next generation of food-web studies to reconcile the structure and function of biodiversity.No Full Tex
Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans
Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have
fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in
25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16
regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of
correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP,
while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in
Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium
(LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region.
Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant
enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the
refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa,
an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of
PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent
signals within the same regio
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