61 research outputs found

    GPR120 controls neonatal brown adipose tissue thermogenic induction

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    Adaptive induction of thermogenesis in brown adipose tissue (BAT) is essential for the survival of mammals after birth. We herein show that G-coupled receptor protein-120 (GPR120) expression is dramatically induced after birth in mouse BAT. GPR120 expression in neonatal BAT is the highest among GPR120-expressing tissues in mouse at any developmental stage tested. The induction of GPR120 in neonatal BAT is caused by the postnatal thermal stress rather than by the initiation of suckling. GPR120-null neonates were found to be relatively intolerant to cold: close to one-third did not survive at 21ÂșC, but all such pups survived at 25ÂșC. Heat production in BAT was significantly impaired in GPR120-null pups. Deficiency in GPR120 did not modify brown adipocyte morphology or the anatomical architecture of BAT, as assessed by electron microscopy, but instead impaired the expression of UCP1 and the fatty acid oxidation capacity of neonatal BAT. Moreover, GPR120 deficiency impaired FGF21 gene expression in BAT and reduced plasma FGF21 levels. These results indicate that GPR120 is essential for neonatal adaptive thermogenesis through the control of the FGF21 system

    Influence of Subclinical Atherosclerosis Burden and Progression on Mortality.

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    BACKGROUND: Atherosclerosis is a dynamic process. There is little evidence regarding whether quantification of atherosclerosis extent and progression, particularly in the carotid artery, in asymptomatic individuals predicts all-cause mortality. OBJECTIVES: This study sought to evaluate the independent predictive value (beyond cardiovascular risk factors) of subclinical atherosclerosis burden and progression and all-cause mortality. METHODS: A population of 5,716 asymptomatic U.S. adults (mean age 68.9 years, 56.7% female) enrolled between 2008 and 2009 in the BioImage (A Clinical Study of Burden of Atherosclerotic Disease in an At Risk Population) study underwent examination by vascular ultrasound to quantify carotid plaque burden (cPB) (the sum of right and left carotid plaque areas) and by computed tomography for coronary artery calcium (CAC). Follow-up carotid vascular ultrasound was performed on 732 participants a median of 8.9 years after the baseline exam. All participants were followed up for all-cause mortality, the primary outcome. Trend HRs are the per-tertile increase in each variable. RESULTS: Over a median 12.4 years' follow-up, 901 (16%) participants died. After adjustment for cardiovascular risk factors and background medication, baseline cPB and CAC score were both significantly associated with all-cause mortality (fully adjusted trend HR: 1.23; 95% CI: 1.16-1.32; and HR: 1.15; 95% CI: 1.08-1.23), respectively (both P < 0.001), thus providing additional prognostic value. cPB performed better than CAC score. In participants with a second vascular ultrasound evaluation, median cPB progressed from 29.2 to 91.3 mm3. cPB progression was significantly associated with all-cause mortality after adjusting for cardiovascular risk factors and baseline cPB (HR: 1.03; 95% CI: 1.01-1.04 per absolute 10-mm3 change; P = 0.01). CONCLUSIONS: Subclinical atherosclerosis burden (cPB and CAC) in asymptomatic individuals was independently associated with all-cause mortality. Moreover, atherosclerosis progression was independently associated with all-cause mortality

    Reciprocal Effects of Antiretroviral Drugs Used To Treat HIV Infection on the Fibroblast Growth Factor 21/ÎČ-Klotho System

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    Following antiretroviral therapy, HIV-infected patients show increased circulating levels of the antidiabetic hormone fibroblast growth factor 21 (FGF21). In contrast, the expression of the FGF21-obligatory coreceptor ÎČ-Klotho (KLB) is reduced in target tissues. This situation is comparable to the FGF21 resistance status observed in obesity and type 2 diabetes. Here, we performed the first systematic study of the effects of distinct members of different antiretroviral drug classes on the FGF21/KLB system in human hepatic, adipose, and skeletal muscle cells. Most protease inhibitors and the nonnucleoside reverse transcriptase inhibitor efavirenz induced FGF21 gene expression. Neither nucleoside reverse transcriptase inhibitors nor the viral entry inhibitor maraviroc had any effect. Among the integrase inhibitors, elvitegravir significantly induced FGF21 expression, whereas raltegravir had minor effects only in adipose cells. In human hepatocytes and adipocytes, known target cells of FGF21 action, efavirenz, elvitegravir, and the lopinavir-ritonavir combination exerted inhibitory effects on KLB gene expression. Drug treatments that elicited FGF21 induction/KLB repression were those found to induce endoplasmic reticulum (ER) stress and oxidative stress. Notably, the pharmacological agents thapsigargin and tunicamycin, which induce these stress pathways, mimicked the effects of drug treatments. Moreover, pharmacological inhibitors of either ER or oxidative stress significantly impaired lopinavir-ritonavir-induced regulation of FGF21, but not KLB. In conclusion, the present in vitro screen study identifies the antiretroviral drugs that affect FGF21/KLB expression in human cells. The present results could have important implications for the management of comorbidities resulting from side effects of specific antiretroviral drugs for the treatment of HIV-infected patients

    Mitochondrial physiology

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    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

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    Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≄ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

    COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

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    Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≀ 18 years: 69, 48, 23; 85%), older adults (≄ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P &lt; 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

    Genetic diversity, population structure, and resistance to Phytophthora capsici of a worldwide collection of eggplant germplasm.

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    Eggplant (Solanum melongena L.) is an important solanaceous crop with high phenotypic diversity and moderate genotypic diversity. Ninety-nine genotypes of eggplant germplasm (species (S. melongena, S. incanum, S. linnaeanum and S. gilo), landraces and heirloom cultivars) from 32 countries and five continents were evaluated for genetic diversity, population structure, fruit shape, and disease resistance to Phytophthora fruit rot. Fruits from each line were measured for fruit shape and evaluated for resistance to two Phytophthora capsici isolates seven days post inoculation. Only one accession (PI 413784) was completely resistant to both isolates evaluated. Partial resistance to Phytophthora fruit rot was found in accessions from all four eggplant species evaluated in this study. Genetic diversity and population structure were assessed using 22 polymorphic simple sequence repeats (SSRs). The polymorphism information content (PIC) for the population was moderate (0.49) in the population. Genetic analyses using the program STRUCTURE indicated the existence of four genetic clusters within the eggplant collection. Population structure was detected when eggplant lines were grouped by species, continent of origin, country of origin, fruit shape and disease resistance

    Babesia bovis Rad51 ortholog influences switching of ves genes but is not essential for segmental gene conversion in antigenic variation.

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    The tick-borne apicomplexan parasite, Babesia bovis, a highly persistent bovine pathogen, expresses VESA1 proteins on the infected erythrocyte surface to mediate cytoadhesion. The cytoadhesion ligand, VESA1, which protects the parasite from splenic passage, is itself protected from a host immune response by rapid antigenic variation. B. bovis relies upon segmental gene conversion (SGC) as a major mechanism to vary VESA1 structure. Gene conversion has been considered a form of homologous recombination (HR), a process for which Rad51 proteins are considered pivotal components. This could make BbRad51 a choice target for development of inhibitors that both interfere with parasite genome integrity and disrupt HR-dependent antigenic variation. Previously, we knocked out the Bbrad51 gene from the B. bovis haploid genome, resulting in a phenotype of sensitivity to methylmethane sulfonate (MMS) and apparent loss of HR-dependent integration of exogenous DNA. In a further characterization of BbRad51, we demonstrate here that ΔBbrad51 parasites are not more sensitive than wild-type to DNA damage induced by Îł-irradiation, and repair their genome with similar kinetics. To assess the need for BbRad51 in SGC, RT-PCR was used to observe alterations to a highly variant region of ves1α transcripts over time. Mapping of these amplicons to the genome revealed a significant reduction of in situ transcriptional switching (isTS) among ves loci, but not cessation. By combining existing pipelines for analysis of the amplicons, we demonstrate that SGC continues unabated in ΔBbrad51 parasites, albeit at an overall reduced rate, and a reduction in SGC tract lengths was observed. By contrast, no differences were observed in the lengths of homologous sequences at which recombination occurred. These results indicate that, whereas BbRad51 is not essential to babesial antigenic variation, it influences epigenetic control of ves loci, and its absence significantly reduces successful variation. These results necessitate a reconsideration of the likely enzymatic mechanism(s) underlying SGC and suggest the existence of additional targets for development of small molecule inhibitors
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