175 research outputs found

    Activation of hypoxia-inducible factor-2 in adipocytes results in pathological cardiac hypertrophy.

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    BACKGROUND: Obesity can cause structural and functional abnormalities of the heart via complex but largely undefined mechanisms. Emerging evidence has shown that obesity results in reduced oxygen concentrations, or hypoxia, in adipose tissue. We hypothesized that the adipocyte hypoxia-signaling pathway plays an essential role in the development of obesity-associated cardiomyopathy. METHODS AND RESULTS: Using a mouse model in which the hypoxia-inducible factor (HIF) pathway is activated by deletion of the von Hippel-Lindau gene specifically in adipocytes, we found that mice with adipocyte-von Hippel-Lindau deletion developed lethal cardiac hypertrophy. HIF activation in adipocytes results in overexpression of key cardiomyopathy-associated genes in adipose tissue, increased serum levels of several proinflammatory cytokines including interleukin-1β and monocyte chemotactic protein-1, and activation of nuclear factor-κB and nuclear factor of activated T cells in the heart. Interestingly, genetic deletion of Hif2a, but not Hif1a, was able to rescue cardiac hypertrophy and abrogate adipose inflammation. CONCLUSION: We have discovered a previously uncharacterized mechanism underlying a critical and direct role of the adipocyte HIF-2 transcription factor in the development of adipose inflammation and pathological cardiac hypertrophy

    Ocean warming, a rapid distributional shift, and the hybridization of a coastal fish species

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    Despite increasing awareness of large-scale climate-driven distribution shifts in the marine environment, no study has linked rapid ocean warming to a shift in distribution and consequent hybridization of a marine fish species. This study describes rapid warming (0.8 °C per decade) in the coastal waters of the Angola-Benguela Frontal Zone over the last three decades and a concomitant shift by a temperature sensitive coastal fish species (Argyrosomus coronus) southward from Angola into Namibia. In this context, rapid shifts in distribution across Economic Exclusive Zones will complicate the management of fishes, particularly when there is a lack of congruence in the fisheries policy between nations. Evidence for recent hybridization between A. coronus and a congener, A. inodorus, indicate that the rapid shift in distribution of A. coronus has placed adults of the two species in contact during their spawning events. Ocean warming may therefore revert established species isolation mechanisms and alter the evolutionary history of fishes. While the consequences of the hybridization on the production of the resource remain unclear, this will most likely introduce additional layers of complexity to their management

    miR-34a Silences c-SRC to Attenuate Tumor Growth in Triple-Negative Breast Cancer

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    Triple-negative breast cancer (TNBC) is an aggressive subtype with no clinically proven biologically targeted treatment options. The molecular heterogeneity of TNBC and lack of high frequency driver mutations other than TP53 have hindered the development of new and effective therapies that significantly improve patient outcomes. miRNAs, global regulators of survival and proliferation pathways important in tumor development and maintenance, are becoming promising therapeutic agents. We performed miRNA-profiling studies in different TNBC subtypes to identify miRNAs that significantly contribute to disease progression. We found that miR-34a was lost in TNBC, specifically within mesenchymal and mesenchymal stem cell-like subtypes, whereas expression of miR-34a targets was significantly enriched. Furthermore, restoration of miR-34a in cell lines representing these subtypes inhibited proliferation and invasion, activated senescence, and promoted sensitivity to dasatinib by targeting the proto-oncogene c-SRC. Notably, SRC depletion in TNBC cell lines phenocopied the effects of miR-34a reintroduction, whereas SRC overexpression rescued the antitumorigenic properties mediated by miR-34a. miR-34a levels also increased when cells were treated with c-SRC inhibitors, suggesting a negative feedback exists between miR-34a and c-SRC. Moreover, miR-34a administration significantly delayed tumor growth of subcutaneously and orthotopically implanted tumors in nude mice, and was accompanied by c-SRC downregulation. Finally, we found that miR-34a and SRC levels were inversely correlated in human tumor specimens. Together, our results demonstrate that miR-34a exerts potent antitumorigenic effects in vitro and in vivo and suggests that miR-34a replacement therapy, which is currently being tested in human clinical trials, represents a promising therapeutic strategy for TNBC. Cancer Res; 76(4); 1-13. (c)2015 AACR

    COVID-19: Metro Recovery Index in the Mountain West

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    Amid the COVID-19 pandemic and the economic recession that is developing as a result, researchers at the Brookings Institution created the “Metro Recovery Index dashboard,” an interactive data set that tracks changes in labor, real estate, and other economic indicators for metropolitan areas throughout the U.S. Using data from January – June 2020, this Fact Sheets highlights the impact of the COVID-19 recession on 13 Metropolitan Statistical Areas (MSAs) in 5 Mountain West states: Arizona, Colorado, Nevada, New Mexico, and Utah

    Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis.

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    Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis

    Clinical characteristics and risk behavior as a function of HIV status among heroin users enrolled in methadone treatment in northern Taiwan

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    <p>Abstract</p> <p>Background</p> <p>Methadone treatment was introduced in Taiwan in 2006 as a harm-reduction program in response to the human immunodeficiency virus (HIV), which is endemic among Taiwanese heroin users. The present study was aimed at examining the clinical and behavioral characteristics of methadone patients in northern Taiwan according to their HIV status.</p> <p>Methods</p> <p>The study was conducted at four methadone clinics. Participants were patients who had undergone methadone treatment at the clinics and who voluntarily signed a consent form. Between August and November 2008, each participant completed a face-to-face interview that included questions on demographics, risk behavior, quality of life, and psychiatric symptoms. Data on HIV and hepatitis C virus (HCV) infections, methadone dosage, and morphine in the urine were retrieved from patient files on the clinical premises, with permission of the participants.</p> <p>Results</p> <p>Of 576 participants, 71 were HIV positive, and 514 had hepatitis C. There were significant differences between the HIV-positive and HIV-negative groups on source of treatment payment, HCV infection, urine test results, methadone dosage, and treatment duration. The results indicate that HIV-negative heroin users were more likely to have sexual intercourse and not use condoms during the 6 months prior to the study. A substantial percent of the sample reported anxiety (21.0%), depression (27.2%), memory loss (32.7%), attempted suicide (32.7%), and administration of psychiatric medications (16.1%). There were no significant differences between the HIV-positive and HIV-negative patients on psychiatric symptoms or quality of life.</p> <p>Conclusions</p> <p>HIV-positive IDUs were comorbid with HCV, indicating the need to refer both HIV- and HCV-infected individuals for treatment in methadone clinics. Currently, there is a gap between psychiatric/psychosocial services and patient symptoms, and more integrated medical services should be provided to heroin-using populations.</p

    Employing a Gain-of-Function Factor IX Variant R338L to Advance the Efficacy and Safety of Hemophilia B Human Gene Therapy: Preclinical Evaluation Supporting an Ongoing Adeno-Associated Virus Clinical Trial

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    AbstractVector capsid dose-dependent inflammation of transduced liver has limited the ability of adeno-associated virus (AAV) factor IX (FIX) gene therapy vectors to reliably convert severe to mild hemophilia B in human clinical trials. These trials also identified the need to understand AAV neutralizing antibodies and empty AAV capsids regarding their impact on clinical success. To address these safety concerns, we have used a scalable manufacturing process to produce GMP-grade AAV8 expressing the FIXR338L gain-of-function variant with minimal (<10%) empty capsid and have performed comprehensive dose–response, biodistribution, and safety evaluations in clinically relevant hemophilia models. The scAAV8.FIXR338L vector produced greater than 6-fold increased FIX specific activity compared with wild-type FIX and demonstrated linear dose responses from doses that produced 2–500% FIX activity, associated with dose-dependent hemostasis in a tail transection bleeding challenge. More importantly, using a bleeding model that closely mimics the clinical morbidity of hemophilic arthropathy, mice that received the scAAV8.FIXR338L vector developed minimal histopathological findings of synovitis after hemarthrosis, when compared with mice that received identical doses of wild-type FIX vector. Hemostatically normal mice (n=20) and hemophilic mice (n=88) developed no FIX antibodies after peripheral intravenous vector delivery. No CD8+ T cell liver infiltrates were observed, despite the marked tropism of scAAV8.FIXR338L for the liver in a comprehensive biodistribution evaluation (n=60 animals). With respect to the role of empty capsids, we demonstrated that in vivo FIXR338L expression was not influenced by the presence of empty AAV particles, either in the presence or absence of various titers of AAV8-neutralizing antibodies. Necropsy of FIX–/– mice 8–10 months after vector delivery revealed no microvascular or macrovascular thrombosis in mice expressing FIXR338L (plasma FIX activity, 100–500%). These preclinical studies demonstrate a safety:efficacy profile supporting an ongoing phase 1/2 human clinical trial of the scAAV8.FIXR338L vector (designated BAX335)

    Relocating participation within a radical politics of development

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    In response to (and in sympathy with) many of the critical points that have been lodged against participatory approaches to development and governance within international development, this article seeks to relocate participation within a radical politics of development. We argue that participation needs to be theoretically and strategically informed by a notion of ‘citizenship’, and be located within the ‘critical modernist’ approach to development. Using empirical evidence drawn from a wide range of contemporary approaches to participation, the paper shows that participatory approaches are most likely to succeed where (i) they are pursued as part of a wider radical political project; (ii) where they are aimed specifically at securing citizenship rights and participation for marginal and subordinate groups; and (iii) when they seek to engage with development as an underlying process of social change rather than in the form of discrete technocratic interventions. However, we do not use these findings to argue against using participatory methods where these conditions are not met. Finally, the paper considers the implications of this relocation for participation in both theoretical and strategic terms

    Helios Expression Is a Marker of T Cell Activation and Proliferation

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    Foxp3+ T-regulatory cells (Tregs) normally serve to attenuate immune responses and are key to maintenance of immune homeostasis. Over the past decade, Treg cells have become a major focus of research for many groups, and various functional subsets have been characterized. Recently, the Ikaros family member, Helios, was reported as a marker to discriminate naturally occurring, thymic-derived Tregs from those peripherally induced from naïve CD4+ T cells. We investigated Helios expression in murine and human T cells under resting or activating conditions, using well-characterized molecules of naïve/effector/memory phenotypes, as well as a set of Treg-associated markers. We found that Helios-negative T cells are enriched for naïve T cell phenotypes and vice versa. Moreover, Helios can be induced during T cell activation and proliferation, but regresses in the same cells under resting conditions. We demonstrated comparable findings using human and murine CD4+Foxp3+ Tregs, as well as in CD4+ and CD8+ T cells. Since Helios expression is associated with T cell activation and cellular division, regardless of the cell subset involved, it does not appear suitable as a marker to distinguish natural and induced Treg cells
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