scholarly journals ICOS signaling limits regulatory T cell accumulation and function in visceral adipose tissue

2020 ◽  
Author(s):  
Kristen L. Mittelsteadt ◽  
Daniel J. Campbell
Keyword(s):  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Visceral Adipose Tissue ◽  
High Fat Diet ◽  
Costimulatory Molecule ◽  
Cell Accumulation ◽  
Elevated Expression ◽  
And Function ◽  
Adipose Inflammation ◽  
Visceral Adipose

AbstractA unique population of Foxp3+ regulatory T cells (TR) resides in visceral adipose tissue (VAT) that regulates adipose inflammation and helps preserve insulin sensitivity. The costimulatory molecule ICOS is highly expressed on effector (e)TR that migrate to nonlymphoid tissues, and contributes to their maintenance and function in models of autoimmunity. In this study, we report an unexpected cell-intrinsic role for ICOS expression and downstream PI3K signaling in limiting the abundance, VAT-associated phenotype, and function of TR specifically in VAT. Icos−/− mice and mice expressing a knock-in form of ICOS that cannot activate PI3K had increased VAT-TR abundance and elevated expression of canonical VAT-TR markers. Loss of ICOS signaling facilitated enhanced accumulation of TR to VAT associated with elevated CCR3 expression, and resulted in reduced adipose inflammation and heightened insulin sensitivity in the context of high-fat diet. Thus, we have uncovered a new and surprising molecular pathway that regulates VAT-TR accumulation and function.

scholarly journals ICOS signaling limits regulatory T cell accumulation and function in visceral adipose tissue

2021 ◽  
Vol 218 (6) ◽  
Author(s):  
Kristen L. Mittelsteadt ◽  
Erika T. Hayes ◽  
Daniel J. Campbell
Keyword(s):  
Adipose Tissue ◽  
T Cell ◽  
Insulin Sensitivity ◽  
Visceral Adipose Tissue ◽  
Cell Accumulation ◽  
Elevated Expression ◽  
Phosphoinositide 3 Kinase ◽  
And Function ◽  
Adipose Inflammation ◽  
Visceral Adipose

A unique population of Foxp3+ regulatory T cells (TRs) resides in visceral adipose tissue (VAT) that regulates adipose inflammation and helps preserve insulin sensitivity. Inducible T cell co-stimulator (ICOS) is highly expressed on effector (e)TRs that migrate to nonlymphoid tissues, and contributes to their maintenance and function in models of autoimmunity. In this study, we report an unexpected cell-intrinsic role for ICOS expression and downstream phosphoinositide 3-kinase (PI3K) signaling in limiting the abundance, VAT-associated phenotype, and function of TRs specifically in VAT. Icos−/− mice and mice expressing a knock-in form of ICOS that cannot activate PI3K had increased VAT-TR abundance and elevated expression of canonical VAT-TR markers. Loss of ICOS signaling facilitated enhanced accumulation of TRs to VAT associated with elevated CCR3 expression, and resulted in reduced adipose inflammation and heightened insulin sensitivity in the context of a high-fat diet. Thus, we have uncovered a new and surprising molecular pathway that regulates VAT-TR accumulation and function.

scholarly journals LMO3 reprograms visceral adipocyte metabolism during obesity

2021 ◽  
Author(s):  
Gabriel Wagner ◽  
Anna Fenzl ◽  
Josefine Lindroos-Christensen ◽  
Elisa Einwallner ◽  
Julia Husa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Glucose Uptake ◽  
Visceral Adipose Tissue ◽  
Tissue Expansion ◽  
Oxidative Capacity ◽  
Glut4 Translocation ◽  
Mitochondrial Oxidative Capacity ◽  
Visceral Adipose

Abstract Obesity and body fat distribution are important risk factors for the development of type 2 diabetes and metabolic syndrome. Evidence has accumulated that this risk is related to intrinsic differences in behavior of adipocytes in different fat depots. We recently identified LIM domain only 3 (LMO3) in human mature visceral adipocytes; however, its function in these cells is currently unknown. The aim of this study was to determine the potential involvement of LMO3-dependent pathways in the modulation of key functions of mature adipocytes during obesity. Based on a recently engineered hybrid rAAV serotype Rec2 shown to efficiently transduce both brown adipose tissue (BAT) and white adipose tissue (WAT), we delivered YFP or Lmo3 to epididymal WAT (eWAT) of C57Bl6/J mice on a high-fat diet (HFD). The effects of eWAT transduction on metabolic parameters were evaluated 10 weeks later. To further define the role of LMO3 in insulin-stimulated glucose uptake, insulin signaling, adipocyte bioenergetics, as well as endocrine function, experiments were conducted in 3T3-L1 adipocytes and newly differentiated human primary mature adipocytes, engineered for transient gain or loss of LMO3 expression, respectively. AAV transduction of eWAT results in strong and stable Lmo3 expression specifically in the adipocyte fraction over a course of 10 weeks with HFD feeding. LMO3 expression in eWAT significantly improved insulin sensitivity and healthy visceral adipose tissue expansion in diet-induced obesity, paralleled by increased serum adiponectin. In vitro, LMO3 expression in 3T3-L1 adipocytes increased PPARγ transcriptional activity, insulin-stimulated GLUT4 translocation and glucose uptake, as well as mitochondrial oxidative capacity in addition to fatty acid oxidation. Mechanistically, LMO3 induced the PPARγ coregulator Ncoa1, which was required for LMO3 to enhance glucose uptake and mitochondrial oxidative gene expression. In human mature adipocytes, LMO3 overexpression promoted, while silencing of LMO3 suppressed mitochondrial oxidative capacity. LMO3 expression in visceral adipose tissue regulates multiple genes that preserve adipose tissue functionality during obesity, such as glucose metabolism, insulin sensitivity, mitochondrial function, and adiponectin secretion. Together with increased PPARγ activity and Ncoa1 expression, these gene expression changes promote insulin-induced GLUT4 translocation, glucose uptake in addition to increased mitochondrial oxidative capacity, limiting HFD-induced adipose dysfunction. These data add LMO3 as a novel regulator improving visceral adipose tissue function during obesity. Key messages LMO3 increases beneficial visceral adipose tissue expansion and insulin sensitivity in vivo. LMO3 increases glucose uptake and oxidative mitochondrial activity in adipocytes. LMO3 increases nuclear coactivator 1 (Ncoa1). LMO3-enhanced glucose uptake and mitochondrial gene expression requires Ncoa1.

Trans-palmitoleic Acid Reduces Adiposity via Increased Lipolysis in a Rodent Model of Diet-Induced Obesity

2021 ◽  
pp. 1-24
Author(s):  
L. Irasema Chávaro-Ortiz ◽  
Brenda D. Tapia-Vargas ◽  
Mariel Rico-Hidalgo ◽  
Ruth Gutiérrez-Aguilar ◽  
María E. Frigolet
Keyword(s):  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Visceral Adipose Tissue ◽  
High Fat Diet ◽  
Palmitoleic Acid ◽  
Rodent Model ◽  
Adipocyte Size ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Visceral Adipose

Abstract Obesity is defined as increased adiposity, which leads to metabolic disease. The growth of adipose tissue depends on its capacity to expand, through hyperplasia or hypertrophy, in order to buffer energy surplus. Also, during the establishment of obesity, adipose tissue expansion reflects adipose lipid metabolism (lipogenesis and/or lipolysis). It is well known that dietary factors can modify lipid metabolism promoting or preventing the development of metabolic abnormalities that concur with obesity. Trans-palmitoleic acid (TP), a biomarker of dairy consumption, has been associated with reduced adiposity in clinical studies. Thus, we aimed to evaluate the effect of TP over adiposity and lipid metabolism-related genes in a rodent model of diet-induced obesity (DIO). To fulfil this aim, we fed C57BL/6 mice with a Control or a High Fat diet, added with or without TP (3g/kg diet), during 11 weeks. Body weight and food intake were monitored, fat pads were weighted, histology of visceral adipose tissue was analysed, and lipid metabolism-related gene expression was explored by qPCR. Results show that TP consumption prevented weight gain induced by high fat diet, reduced visceral adipose tissue weight, and adipocyte size, while increasing the expression of lipolytic molecules. In conclusion, we show for the first time that TP influences adipose tissue metabolism, specifically lipolysis, resulting in decreased adiposity and reduced adipocyte size in a DIO mice model.

Enhanced Inflammation without Impairment of Insulin Signaling in the Visceral Adipose Tissue of 5α-Dihydrotestosterone-Induced Animal Model of Polycystic Ovary Syndrome

2017 ◽  
Vol 125 (08) ◽  
pp. 522-529 ◽  
Author(s):  
Danijela Milutinović ◽  
Marina Nikolić ◽  
Nataša Veličković ◽  
Ana Djordjevic ◽  
Biljana Bursać ◽  
...  
Keyword(s):  
Animal Model ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Polycystic Ovary Syndrome ◽  
Abdominal Obesity ◽  
Visceral Adipose Tissue ◽  
Polycystic Ovary ◽  
Low Grade ◽  
Ovary Syndrome ◽  
Visceral Adipose

AbstractPolycystic ovary syndrome is a heterogeneous endocrine and metabolic disorder associated with abdominal obesity, dyslipidemia and insulin resistance. Since abdominal obesity is characterized by low-grade inflammation, the aim of the study was to investigate whether visceral adipose tissue inflammation linked to abdominal obesity and dyslipidemia could lead to impaired insulin sensitivity in the animal model of polycystic ovary syndrome.Female Wistar rats were treated with nonaromatizable 5α-dihydrotestosterone pellets in order to induce reproductive and metabolic characteristics of polycystic ovary syndrome. Glucose, triglycerides, non-esterified fatty acids and insulin were determined in blood plasma. Visceral adipose tissue inflammation was evaluated by the nuclear factor kappa B intracellular distribution, macrophage migration inhibitory factor protein level, as well as TNFα, IL6 and IL1β mRNA levels. Insulin sensitivity was assessed by intraperitoneal glucose tolerance test and homeostasis model assessment index, and through analysis of insulin signaling pathway in the visceral adipose tissue.Dihydrotestosterone treatment led to increased body weight, abdominal obesity and elevated triglycerides and non-esterified fatty acids, which were accompanied by the activation of nuclear factor kappa B and increase in macrophage migration inhibitory factor, IL6 and IL1β levels in the visceral adipose tissue. In parallel, insulin sensitivity was affected in 5α-dihydrotestosterone-treated animals only at the systemic and not at the level of visceral adipose tissue.The results showed that abdominal obesity and dyslipidemia in the animal model of polycystic ovary syndrome were accompanied with low-grade inflammation in the visceral adipose tissue. However, these metabolic disturbances did not result in decreased tissue insulin sensitivity.

scholarly journals Adipose Inflammation in Obesity: Relationship With Circulating Levels of Inflammatory Markers and Association With Surgery-Induced Weight Loss

2014 ◽  
Vol 99 (1) ◽  
pp. E53-E61 ◽  
Author(s):  
Julie Lasselin ◽  
Eric Magne ◽  
Cédric Beau ◽  
Patrick Ledaguenel ◽  
Sandra Dexpert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bariatric Surgery ◽  
Weight Loss ◽  
Adipose Tissue ◽  
Visceral Adipose Tissue ◽  
Inflammatory Markers ◽  
Tnf Α ◽  
Inflammatory State ◽  
Adipose Inflammation ◽  
Visceral Adipose

Context: The inflammatory state of the adipose tissue is believed to contribute to systemic low-grade inflammation in obesity. Objective: This study assessed the relationship between adipose and circulating inflammatory markers as well as the influence of adipose inflammation on bariatric surgery-induced weight reduction. Design: This was a cross-sectional and longitudinal study (up to 14 mo). Setting: The study was conducted in the digestive/bariatric surgery department of the Tivoli and Jean Villar clinics, Bordeaux, France. Patients: Thirty-seven obese patients [body mass index (BMI) > 35–40 kg/m2)] seeking bariatric surgery were included. Twenty-eight of them were successively followed up at 1–3 months after surgery and 25 between 6 and 14 months after surgery. Main Outcome Measures: Fasting serum samples were collected before surgery to assess concentrations of inflammatory markers. Samples of visceral adipose tissue were extracted during surgery and gene expression of cytokines and immune cell markers were evaluated using quantitative RT-PCR. Pre- and postsurgery weight and BMI were collected. Results: Gene expression of several cytokines were strongly intercorrelated in the visceral adipose tissue. Adipose expression of macrophage and T cell markers were related to adipose expression of TNF-α and IL-1 receptor antagonist (P < .01) and to systemic levels of TNF-α (P < .01) and IL-6 (P < .05). A higher inflammatory state of the adipose tissue predicted a lower BMI reduction after surgery (P < .05), notably at early stages after surgery. Conclusions: These findings support the involvement of macrophages and T cells in adipose inflammation and provide new information regarding the role of the visceral adipose tissue in the inflammatory state of obesity and its impact on obesity treatment outcomes, such as surgery-induced weight loss.

Whole-body skeletal muscle mass is not related to glucose tolerance or insulin sensitivity in overweight and obese men and women

2008 ◽  
Vol 33 (4) ◽  
pp. 769-774 ◽  
Author(s):  
Jennifer L. Kuk ◽  
Katherine Kilpatrick ◽  
Lance E. Davidson ◽  
Robert Hudson ◽  
Robert Ross
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Muscle Mass ◽  
Visceral Adipose Tissue ◽  
Skeletal Muscle Mass ◽  
Whole Body ◽  
Men And Women ◽  
Visceral Adipose

The relationship between skeletal muscle mass, visceral adipose tissue, insulin sensitivity, and glucose tolerance was examined in 214 overweight or obese, but otherwise healthy, men (n = 98) and women (n = 116) who participated in various exercise and (or) weight-loss intervention studies. Subjects had a 75 g oral glucose tolerance test and (or) insulin sensitivity measures by a 3 h hyperinsulinemic–euglycemic clamp technique. Whole-body skeletal muscle mass and visceral adipose tissue were measured using a multi-slice magnetic resonance imaging protocol. Total body skeletal muscle mass was not associated with any measure of glucose metabolism in men or women (p > 0.10). These observations remained independent of age and total adiposity. Conversely, visceral adipose tissue was a significant predictor of various measures of glucose metabolism in both men and women with or without control for age and (or) total body fat (p < 0.05). Although skeletal muscle is a primary site for glucose uptake and deposition, these findings suggest that unlike visceral adipose tissue, whole-body skeletal muscle mass per se is not associated with either glucose tolerance or insulin sensitivity in overweight and obese men and women.

Visceral adipose tissue impairs insulin secretion and insulin sensitivity but not energy expenditure in obesity

Metabolism ◽  
1997 ◽  
Vol 46 (2) ◽  
pp. 123-129 ◽  
Author(s):  
C. Macor ◽  
A. Ruggeri ◽  
P. Mazzonetto ◽  
G. Federspil ◽  
C. Cobelli ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Energy Expenditure ◽  
Visceral Adipose Tissue ◽  
Visceral Adipose
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