Leptin Inhibits the Proliferation of Vascular Smooth Muscle Cells Induced by Angiotensin II through Nitric Oxide-Dependent Mechanisms

Objective. This study was designed to investigate whether leptin modifies angiotensin (Ang) II-induced proliferation of aortic vascular smooth muscle cells (VSMCs) from 10-week-old male Wistar and spontaneously hypertensive rats (SHR), and the possible role of nitric oxide (NO). Methods. NO and NO synthase (NOS) activity were assessed by the Griess and 3H-arginine/citrulline conversion assays, respectively. Inducible NOS (iNOS) and NADPH oxidase subutnit Nox2 expression was determined by Western-blot. The proliferative responses to Ang II were evaluated through enzymatic methods. Results. Leptin inhibited the Ang II-induced proliferative response of VSMCs from control rats. This inhibitory effect of leptin was abolished by NOS inhibitor, NMMA, and iNOS selective inhibitor, L-NIL, and was not observed in leptin receptor-deficient fa/fa rats. SHR showed increased serum leptin concentrations and lipid peroxidation. Despite a similar leptin-induced iNOS up-regulation, VSMCs from SHR showed an impaired NOS activity and NO production induced by leptin, and an increased basal Nox2 expression. The inhibitory effect of leptin on Ang II-induced VSMC proliferation was attenuated. Conclusion. Leptin blocks the proliferative response to Ang II through NO-dependent mechanisms. The attenuation of this inhibitory effect of leptin in spontaneous hypertension appears to be due to a reduced NO bioavailability in VSMCs

Leptin Administration Downregulates the Increased Expression Levels of Genes Related to Oxidative Stress and Inflammation in the Skeletal Muscle of ob/ob Mice

Obese leptin-deficient ob/ob mice exhibit a low-grade chronic inflammation together with a low muscle mass. Our aim was to analyze the changes in muscle expression levels of genes related to oxidative stress and inflammatory responses in leptin deficiency and to identify the effect of in vivo leptin administration. Ob/ob mice were divided in three groups as follows: control ob/ob, leptin-treated ob/ob (1 mg/kg/d) and leptin pair-fed ob/ob mice. Gastrocnemius weight was lower in control ob/ob than in wild type mice (P < .01) exhibiting an increase after leptin treatment compared to control and pair-fed (P < .01) ob/ob animals. Thiobarbituric acid reactive substances, markers of oxidative stress, were higher in serum (P < .01) and gastrocnemius (P = .05) of control ob/ob than in wild type mice and were significantly decreased (P < .01) by leptin treatment. Leptin deficiency altered the expression of 1,546 genes, while leptin treatment modified the regulation of 1,127 genes with 86 of them being involved in oxidative stress, immune defense and inflammatory response. Leptin administration decreased the high expression of Crybb1, Hspb3, Hspb7, Mt4, Cat, Rbm9, Serpinc1 and Serpinb1a observed in control ob/ob mice, indicating that it improves inflammation and muscle loss

Circulating omentin concentration increases after weight loss

<p>Abstract</p> <p>Background</p> <p>Omentin-1 is a novel adipokine expressed in visceral adipose tissue and negatively associated with insulin resistance and obesity. We aimed to study the effects of weight loss-induced improved insulin sensitivity on circulating omentin concentrations.</p> <p>Methods</p> <p>Circulating omentin-1 (ELISA) concentration in association with metabolic variables was measured in 35 obese subjects (18 men, 17 women) before and after hypocaloric weight loss.</p> <p>Results</p> <p>Baseline circulating omentin-1 concentrations correlated negatively with BMI (r = -0.58, p < 0.001), body weight (r = -0.35, p = 0.045), fat mass (r = -0.67, p < 0.001), circulating leptin (r = -0.7, p < 0.001) and fasting insulin (r = -0.37, p = 0.03). Circulating omentin-1 concentration increased significantly after weight loss (from 44.9 ± 9.02 to 53.41 ± 8.8 ng/ml, p < 0.001). This increase in circulating omentin after weight loss was associated with improved insulin sensitivity (negatively associated with HOMA value and fasting insulin, r = -0.42, p = 0.02 and r = -0.45, p = 0.01, respectively) and decreased BMI (r = -0.54, p = 0.001).</p> <p>Conclusion</p> <p>As previously described with adiponectin, circulating omentin-1 concentrations increase after weight loss-induced improvement of insulin sensitivity.</p

Aquaporin-11 Contributes to TGF-β1-Induced Endoplasmic Reticulum Stress in Human Visceral Adipocytes: Role in Obesity-Associated Inflammation

Aquaporin-11 (AQP11) is expressed in human adipocytes, but its functional role remains unknown. Since AQP11 is an endoplasmic reticulum (ER)-resident protein that transports water, glycerol, and hydrogen peroxide (H2O2), we hypothesized that this superaquaporin is involved in ER stress induced by lipotoxicity and inflammation in human obesity. AQP11 expression was assessed in 67 paired visceral and subcutaneous adipose tissue samples obtained from patients with morbid obesity and normal-weight individuals. We found that obesity and obesity-associated type 2 diabetes increased (p < 0.05) AQP11 mRNA and protein in visceral adipose tissue, but not subcutaneous fat. Accordingly, AQP11 mRNA was upregulated (p < 0.05) during adipocyte differentiation and lipolysis, two biological processes altered in the obese state. Subcellular fractionation and confocal microscopy studies confirmed its presence in the ER plasma membrane of visceral adipocytes. Proinflammatory factors TNF-α, and particularly TGF-β1, downregulated (p < 0.05) AQP11 mRNA and protein expression and reinforced its subcellular distribution surrounding lipid droplets. Importantly, the AQP11 gene knockdown increased (p < 0.05) basal and TGF-β1-induced expression of the ER markers ATF4 and CHOP. Together, the downregulation of AQP11 aggravates TGF-β1-induced ER stress in visceral adipocytes. Owing to its “peroxiporin” properties, AQP11 overexpression in visceral fat might constitute a compensatory mechanism to alleviate ER stress in obesity

Increased Levels of Interleukin-36 in Obesity and Type 2 Diabetes Fuel Adipose Tissue Inflammation by Inducing Its Own Expression and Release by Adipocytes and Macrophages

Interleukin (IL)-36 is a recently described cytokine with well-known functions in the regulation of multiple inflammatory diseases. Since no data exists on how this cytokine regulates adipose tissue (AT) homeostasis, we aimed to explore the function of a specific isoform, IL-36γ, an agonist, in human obesity and obesity-associated type 2 diabetes as well as in AT inflammation and fibrosis. Plasma IL-36γ was measured in 91 participants in a case-control study and the effect of weight loss was evaluated in 31 patients with severe obesity undergoing bariatric surgery. Gene expression levels of IL36G and its receptor were analyzed in relevant human metabolic tissues. The effect of inflammatory factors and IL-36γ was determined in vitro in human adipocytes and macrophages. We found, for the first time, that the increased (P&lt;0.05) circulating levels of IL-36γ in patients with obesity decreased (P&lt;0.001) after weight and fat loss achieved by Roux-en-Y gastric bypass and that gene expression levels of IL36G were upregulated in the visceral AT (P&lt;0.05) and in the peripheral blood mononuclear cells (P&lt;0.01) from patients with obesity. We also demonstrated increased (P&lt;0.05) expression levels of Il36g in the epididymal AT from diet-induced obese mice. IL36G was significantly enhanced (P&lt;0.001) by LPS in human adipocytes and monocyte-derived macrophages, while no changes were found after the incubation with anti-inflammatory cytokines. The addition of IL-36γ for 24 h strongly induced (P&lt;0.01) its own expression as well as key inflammatory and chemoattractant factors with no changes in genes associated with fibrosis. Furthermore, adipocyte-conditioned media obtained from patients with obesity increased (P&lt;0.01) the release of IL-36γ and the expression (P&lt;0.05) of cathepsin G (CTSG) in monocyte-derived macrophages. These findings provide, for the first time, evidence about the properties of IL-36γ in the regulation of AT-chronic inflammation, emerging as a link between AT biology and the obesity-associated comorbidities

Study of caveolin-1 gene expression in whole adipose tissue and its subfractions and during differentiation of human adipocytes

<p>Abstract</p> <p>Context</p> <p>Caveolins are 21-24 kDa integral membrane proteins that serve as scaffolds to recruit numerous signaling molecules. Specific subclasses of caveolae carry out specific functions in cell metabolism. In particular, triglycerides are synthesized at the site of fatty acid entry in one of these caveolae classes.</p> <p>Objective and Methods</p> <p>We studied the expression of caveolin-1 (<it>CAV-1</it>) gene in association with metabolic variables in 90 visceral and 55 subcutaneous adipose tissue samples from subjects with a wide range of fat mass, in the stromovascular fraction (SVC) and isolated adipocytes, and during differentiation of human adipocytes.</p> <p>Results</p> <p><it>CAV-1 </it>gene expression was significantly decreased in visceral adipose tissue (v-<it>CAV-1</it>) of obese subjects. v-<it>CAV-1 </it>was positively associated with several lipogenic genes such as acetyl-coA carboxylase (<it>ACACA</it>, r = 0.34, p = 0.004) and <it>spot-14 </it>(r = 0.33, p = 0.004). In non-obese subjects v-<it>CAV-1 </it>also correlated with fatty acid synthase (<it>FAS</it>, r = 0.60, p < 0.0001). Subcutaneous (sc) adipose tissue (s<it>c-CAV-1</it>) gene expression was not associated with these lipogenic factors when obese and non-obese subjects were studied together. In obese subjects, however, sc-<it>CAV-1 </it>was associated with fatty acid synthase (<it>FAS</it>, r = 0.36, p = 0.02), sterol regulatory element binding protein-1c (<it>SREBP-1c </it>(r = 0.58, p < 0.0001), <it>ACACA </it>(r = 0.33, p = 0.03), <it>spot-14 </it>(r = 0.36, p = 0.02), <it>PPAR-γ co-activator-1 </it>(<it>PGC-1</it>, r = 0.88, n = 19). In these obese subjects, <it>sc-CAV-1 </it>was also associated with fasting triglycerides (r = -0.50, p < 0.0001).</p> <p><it>CAV-1 </it>expression in mature adipocytes was significantly higher than in stromal vascular cells. <it>CAV-1 </it>gene expression in adipocytes from subcutaneous adipose tissue (but not in adipocytes from visceral adipose tissue) was significatively associated with fasting triglycerides. <it>CAV-1 </it>gene expression did not change significantly during differentiation of human preadipocytes from lean or obese subjects despite significant increase of FAS gene expression.</p> <p>Conclusion</p> <p>Decreased <it>CAV-1 </it>gene expression was simultaneously linked to increased triglycerides and decreased lipogenic gene expression among obese subjects, paralleling the observations of hypertriglyceridemia in <it>CAV-1 </it>knockout mice. However, the regulation of <it>CAV-1 </it>gene expression seems independent of the adipogenic program.</p

Caloric Restriction Prevents Metabolic Dysfunction and the Changes in Hypothalamic Neuropeptides Associated with Obesity Independently of Dietary Fat Content in Rats

Energy restriction is a first therapy in the treatment of obesity, but the underlying biological mechanisms have not been completely clarified. We analyzed the effects of restriction of high-fat diet (HFD) on weight loss, circulating gut hormone levels and expression of hypothalamic neuropeptides. Ten-week-old male Wistar rats (n = 40) were randomly distributed into four groups: two fed ad libitum a normal diet (ND) (N group) or a HFD (H group) and two subjected to a 25% caloric restriction of ND (NR group) or HFD (HR group) for 9 weeks. A 25% restriction of HFD over 9 weeks leads to a 36% weight loss with regard to the group fed HFD ad libitum accompanied by normal values in adiposity index and food efficiency ratio (FER). This restriction also carried the normalization of NPY, AgRP and POMC hypothalamic mRNA expression, without changes in CART. Caloric restriction did not succeed in improving glucose homeostasis but reduced HFD-induced hyperinsulinemia. In conclusion, 25% restriction of HFD reduced adiposity and improved metabolism in experimental obesity, without changes in glycemia. Restriction of the HFD triggered the normalization of hypothalamic NPY, AgRP and POMC expression, as well as ghrelin and leptin levelsThis work was supported by Ministerio de Economía y Competitividad (SAF2015-71026R) and Fondo de Investigación Sanitaria-FEDER (PI19/00785 and PI19/00990). CIBEROBN is an initiative of the Instituto de Salud Carlos III, SpainS

Epigenome-wide DNA methylation profiling of periprostatic adipose tissue in prostate cancer patients with excess adiposit : a pilot study

© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: Periprostatic adipose tissue (PPAT) has been recognized to associate with prostate cancer (PCa) aggressiveness and progression. Here, we sought to investigate whether excess adiposity modulates the methylome of PPAT in PCa patients. DNA methylation profiling was performed in PPAT from obese/overweight (OB/OW, BMI > 25 kg m−2) and normal weight (NW, BMI < 25 kg m−2) PCa patients. Significant differences in methylated CpGs between OB/OW and NW groups were inferred by statistical modeling. Results: Five thousand five hundred twenty-six differentially methylated CpGs were identified between OB/OW and NW PCa patients with 90.2% hypermethylated. Four hundred eighty-three of these CpGs were found to be located at both promoters and CpG islands, whereas the representing 412 genes were found to be involved in pluripotency of stem cells, fatty acid metabolism, and many other biological processes; 14 of these genes, particularly FADS1, MOGAT1, and PCYT2, with promoter hypermethylation presented with significantly decreased gene expression in matched samples. Additionally, 38 genes were correlated with antigen processing and presentation of endogenous antigen via MHC class I, which might result in fatty acid accumulation in PPAT and tumor immune evasion. Conclusions: Results showed that the whole epigenome methylation profiles of PPAT were significantly different in OB/OW compared to normal weight PCa patients. The epigenetic variation associated with excess adiposity likely resulted in altered lipid metabolism and immune dysregulation, contributing towards unfavorable PCa microenvironment, thus warranting further validation studies in larger samples.This work was supported in part by the Natural Sciences and Engineering Research Council of Canada, Manitoba Research Health Council, University of Manitoba, and China Scholarship Council.info:eu-repo/semantics/publishedVersio

Downregulation of G protein-coupled receptor kinase 2 levels enhances cardiac insulin sensitivity and switches on cardioprotective gene expression patterns

G protein-coupled receptor kinase 2 (GRK2) has recently emerged as a negative modulator of insulin signalling. GRK2 downregulation improves insulin sensitivity and prevents systemic insulin resistance (IR). Cardiac GRK2 levels are increased in 5 human heart failure, while genetically inhibiting GRK2 leads to cardioprotection in mice. However, the molecular basis underlying the 6 deleterious effects of GRK2 up-regulation and the beneficial effects of its inhibition in the heart are not fully understood. Therefore, 7 we have explored the interconnections among a systemic IR status, GRK2 dosage and cardiac insulin sensitivity in adult (9 month-old) animals. GRK2+/- mice display enhanced cardiac insulin sensitivity and mild heart hypertrophy with preserved systolic function. Cardiac gene expression is reprogrammed in these animals, with increased expression of genes related to physiological hypertrophy, while the expression of genes related to pathological hypertrophy or to diabetes/obesity co-morbidities is repressed. Notably, we find that cardiac GRK2 levels increase in situations where IR develops, such as in ob/ob mice or after high fat diet feeding. Our data suggest that GRK2 downregulation/inhibition can help maintain cardiac function in the face of co-morbidities such as IR, diabetes or obesity by sustaining insulin sensitivity and promoting a gene expression reprogramming that confers cardioprotection.Grants from Ministerio de Educación y Ciencia (SAF2011-23800), Fundación para la Investigación Médica Aplicada (FIMA) and UTE project CIMA, The Cardiovascular Network of Ministerio Sanidad y Consumo-Instituto Carlos III (RD06-0014/0037 and RD12/0042/0012), Comunidad de Madrid (S2010/BMD-2332) and EFSD-Novo Nordisk to F.M and UAM Grupo Santander to C.M and Wood-Whelan Research Fellowship from IUBMB to E.L. We also acknowledge institutional support from Fundación Ramón Arece