89 research outputs found

    Predictions for the X-ray circumgalactic medium of edge-on discs and spheroids

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    We investigate how the X-ray circumgalactic medium (CGM) of present-day galaxies depends on galaxy morphology and azimuthal angle using mock observations generated from the EAGLE cosmological hydrodynamic simulation. By creating mock stacks of {\it eROSITA}-observed galaxies oriented to be edge-on, we make several observationally-testable predictions for galaxies in the stellar mass range M=1010.711.2  M_\star=10^{10.7-11.2}\;M_{\odot}. The soft X-ray CGM of disc galaxies is between 60 and 100\% brighter along the semi-major axis compared to the semi-minor axis, between 10-30 kpc. This azimuthal dependence is a consequence of the hot (T>106T>10^6 K) CGM being non-spherical: specifically it is flattened along the minor axis such that denser and more luminous gas resides in the disc plane and co-rotates with the galaxy. Outflows enrich and heat the CGM preferentially perpendicular to the disc, but we do not find an observationally-detectable signature along the semi-minor axis. Spheroidal galaxies have hotter CGMs than disc galaxies related to spheroids residing at higher halos masses, which may be measurable through hardness ratios spanning the 0.21.50.2-1.5 keV band. While spheroids appear to have brighter CGMs than discs for the selected fixed MM_\star bin, this owes to spheroids having higher stellar and halo masses within that MM_\star bin, and obscures the fact that both simulated populations have similar total CGM luminosities at the exact same MM_\star. Discs have brighter emission inside 20 kpc and more steeply declining profiles with radius than spheroids. We predict that the {\it eROSITA} 4-year all-sky survey should detect many of the signatures we predict here, although targeted follow-up observations of highly inclined nearby discs after the survey may be necessary to observe some of our azimuthally-dependent predictions.Comment: 12 pages, 11 figures, 1 table. Submitted to MNRAS. Comments welcom

    Pannexin 3 deletion reduces fat accumulation and inflammation in a sex-specific manner

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    Background: Pannexin 3 (PANX3) is a channel-forming glycoprotein that enables nutrient-induced inflammation in vitro, and genetic linkage data suggest that it regulates body mass index. Here, we characterized inflammatory and metabolic parameters in global Panx3 knockout (KO) mice in the context of forced treadmill running (FEX) and high-fat diet (HFD). Methods: C57BL/6N (WT) and KO mice were randomized to either a FEX running protocol or no running (SED) from 24 until 30 weeks of age. Body weight was measured biweekly, and body composition was measured at 24 and 30 weeks of age. Male WT and KO mice were fed a HFD from 12 to 28 weeks of age. Metabolic organs were analyzed for a panel of inflammatory markers and PANX3 expression. Results: In females there were no significant differences in body composition between genotypes, which could be due to the lack of PANX3 expression in female white adipose tissue, while male KOs fed a chow diet had lower body weight and lower fat mass at 24 and 30 weeks of age, which was reduced to the same extent as 6 weeks of FEX in WT mice. In addition, male KO mice exhibited significantly lower expression of multiple pro-inflammatory genes in white adipose tissue compared to WT mice. While on a HFD body weight differences were insignificant, multiple inflammatory genes were significantly different in quadriceps muscle and white adipose tissue resulting in a more anti-inflammatory phenotype in KO mice compared to WT. The lower fat mass in male KO mice may be due to significantly fewer adipocytes in their subcutaneous fat compared to WT mice. Mechanistically, adipose stromal cells (ASCs) cultured from KO mice grow significantly slower than WT ASCs. Conclusion: PANX3 is expressed in male adult mouse adipose tissue and may regulate adipocyte numbers, influencing fat accumulation and inflammation

    CD10 inhibits cell motility but expression is associated with advanced stage disease in colorectal cancer

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    Introduction CD10 is a cell membrane-bound endopeptidase which is expressed in normal small bowel but not in normal colon. It is aberrantly expressed in a small proportion of colorectal cancers (CRC) and this has been associated with liver metastasis and poor prognosis. We sought to investigate the mechanism of CD10 activity and its association with clinicopathological features. Material and methods CD10 was stably knocked down by lentiviral shRNA transduction in the CRC cell lines SW480 and SW620 which are derived from a primary tumour and its corresponding metastasis respectively. Expression of epithelial – mesenchymal transition (EMT) markers was tested as well as the effect of knockdown on cell viability, migration and invasion assays. In addition, immunohistochemical expression of CD10 in primary colorectal tumours (N = 84) in a tissue microarray was digitally quantified and analysed for associations with clinicopathological variables. Results Knockdown of CD10 did not alter cell viability in SW480, but migration and invasion levels increased (P < 0.001 for each) and this was associated with a cadherin switch. In SW620, CD10 knockdown caused a reduction in cell viability after 72 h (P = 0.0018) but it had no effect on cell migration and invasion. Expression of epithelial CD10 in primary tumours was associated with presence of lymph node invasion (P = 0.001) and advanced Duke's stage (P = 0.001). Conclusions Our results suggest that the function of CD10 may change during tumour evolution. It may inhibit cell motility in early-stage disease whilst promoting cell viability in late-stage disease. It has a complex role and further studies are needed to elucidate the suitability of CD10 as a prognostic marker or therapeutic target

    Integrative genomic analysis implicates limited peripheral adipose storage capacity in the pathogenesis of human insulin resistance.

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    Insulin resistance is a key mediator of obesity-related cardiometabolic disease, yet the mechanisms underlying this link remain obscure. Using an integrative genomic approach, we identify 53 genomic regions associated with insulin resistance phenotypes (higher fasting insulin levels adjusted for BMI, lower HDL cholesterol levels and higher triglyceride levels) and provide evidence that their link with higher cardiometabolic risk is underpinned by an association with lower adipose mass in peripheral compartments. Using these 53 loci, we show a polygenic contribution to familial partial lipodystrophy type 1, a severe form of insulin resistance, and highlight shared molecular mechanisms in common/mild and rare/severe insulin resistance. Population-level genetic analyses combined with experiments in cellular models implicate CCDC92, DNAH10 and L3MBTL3 as previously unrecognized molecules influencing adipocyte differentiation. Our findings support the notion that limited storage capacity of peripheral adipose tissue is an important etiological component in insulin-resistant cardiometabolic disease and highlight genes and mechanisms underpinning this link.This study was funded by the UK Medical Research Council through grants MC_UU_12015/1, MC_PC_13046, MC_PC_13048 and MR/L00002/1. This work was supported by the MRC Metabolic Diseases Unit (MC_UU_12012/5) and the Cambridge NIHR Biomedical Research Centre and EU/EFPIA Innovative Medicines Initiative Joint Undertaking (EMIF grant 115372). Funding for the InterAct project was provided by the EU FP6 program (grant LSHM_CT_2006_037197). This work was funded, in part, through an EFSD Rising Star award to R.A.S. supported by Novo Nordisk. D.B.S. is supported by Wellcome Trust grant 107064. M.I.M. is a Wellcome Trust Senior Investigator and is supported by the following grants from the Wellcome Trust: 090532 and 098381. M.v.d.B. is supported by a Novo Nordisk postdoctoral fellowship run in partnership with the University of Oxford. I.B. is supported by Wellcome Trust grant WT098051. S.O'R. acknowledges funding from the Wellcome Trust (Wellcome Trust Senior Investigator Award 095515/Z/11/Z and Wellcome Trust Strategic Award 100574/Z/12/Z)

    Genetic association analyses implicate aberrant regulation of innate and adaptive immunity genes in the pathogenesis of systemic lupus erythematosus.

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    Systemic lupus erythematosus (SLE) is a genetically complex autoimmune disease characterized by loss of immune tolerance to nuclear and cell surface antigens. Previous genome-wide association studies (GWAS) had modest sample sizes, reducing their scope and reliability. Our study comprised 7,219 cases and 15,991 controls of European ancestry, constituting a new GWAS, a meta-analysis with a published GWAS and a replication study. We have mapped 43 susceptibility loci, including ten new associations. Assisted by dense genome coverage, imputation provided evidence for missense variants underpinning associations in eight genes. Other likely causal genes were established by examining associated alleles for cis-acting eQTL effects in a range of ex vivo immune cells. We found an over-representation (n = 16) of transcription factors among SLE susceptibility genes. This finding supports the view that aberrantly regulated gene expression networks in multiple cell types in both the innate and adaptive immune response contribute to the risk of developing SLE

    Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes.

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    OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis

    New genetic loci link adipose and insulin biology to body fat distribution.

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    Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms
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