scholarly journals AGE/RAGE/DIAPH1 axis is associated with immunometabolic markers and risk of insulin resistance in subcutaneous but not omental adipose tissue in human obesity

2021 ◽  
Author(s):  
Henry H. Ruiz ◽  
Anh Nguyen ◽  
Chan Wang ◽  
Linchen He ◽  
Huilin Li ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Expression Patterns ◽  
Morbidly Obese ◽  
Contributing Factors ◽  
Gene Encoding ◽  
Omental Adipose Tissue ◽  
Cardiometabolic Disorders ◽  
Signaling Axis ◽  
Reduced Physical Activity

Abstract Background/objectives The incidence of obesity continues to increase worldwide and while the underlying pathogenesis remains largely unknown, nutrient excess, manifested by “Westernization” of the diet and reduced physical activity have been proposed as key contributing factors. Western-style diets, in addition to higher caloric load, are characterized by excess of advanced glycation end products (AGEs), which have been linked to the pathophysiology of obesity and related cardiometabolic disorders. AGEs can be “trapped” in adipose tissue, even in the absence of diabetes, in part due to higher expression of the receptor for AGEs (RAGE) and/or decreased detoxification by the endogenous glyoxalase (GLO) system, where they may promote insulin resistance. It is unknown whether the expression levels of genes linked to the RAGE axis, including AGER (the gene encoding RAGE), Diaphanous 1 (DIAPH1), the cytoplasmic domain binding partner of RAGE that contributes to RAGE signaling, and GLO1 are differentially regulated by the degree of obesity and/or how these relate to inflammatory and adipocyte markers and their metabolic consequences. Subjects/methods We sought to answer this question by analyzing gene expression patterns of markers of the AGE/RAGE/DIAPH1 signaling axis in abdominal subcutaneous (SAT) and omental (OAT) adipose tissue from obese and morbidly obese subjects. Results In SAT, but not OAT, expression of AGER was significantly correlated with that of DIAPH1 (n = 16; $$\hat \beta = 0.719$$ β ̂ = 0.719 , [0.260, 1.177]; q = 0.008) and GLO1 (n = 16; $$\hat \beta = 0.773$$ β ̂ = 0.773 , [0.364, 1.182]; q = 0.004). Furthermore, in SAT, but not OAT, regression analyses revealed that the expression pattern of genes in the AGE/RAGE/DIAPH1 axis is strongly and positively associated with that of inflammatory and adipogenic markers. Remarkably, particularly in SAT, not OAT, the expression of AGER positively and significantly correlated with HOMA-IR (n = 14; $$\hat \beta = 0.794$$ β ̂ = 0.794 , [0.338, 1.249]; q = 0.018). Conclusions These observations suggest associations of the AGE/RAGE/DIAPH1 axis in the immunometabolic pathophysiology of obesity and insulin resistance, driven, at least in part, through expression and activity of this axis in SAT.

scholarly journals Differential Expression of MicroRNAs in Omental Adipose Tissue From Gestational Diabetes Mellitus Subjects Reveals miR-222 as a Regulator of ERα Expression in Estrogen-Induced Insulin Resistance

Endocrinology ◽  
2014 ◽  
Vol 155 (5) ◽  
pp. 1982-1990 ◽  
Author(s):  
Zhonghua Shi ◽  
Chun Zhao ◽  
Xirong Guo ◽  
Hongjuan Ding ◽  
Yugui Cui ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Insulin Resistance ◽  
Adipose Tissue ◽  
Gestational Diabetes ◽  
Gestational Diabetes Mellitus ◽  
Differential Expression ◽  
Molecular Mechanisms ◽  
Expression Patterns ◽  
Luciferase Assay ◽  
Omental Adipose Tissue

Omental adipose tissue plays a central role in insulin resistance in gestational diabetes mellitus (GDM), and the molecular mechanisms leading to GDM remains vague. Evidence demonstrates that maternal hormones, such as estradiol, contribute to insulin resistance in GDM. In this study we determined the differential expression patterns of microRNAs (miRNAs) in omental adipose tissues from GDM patients and pregnant women with normal glucose tolerance using AFFX miRNA expression chips. MiR-222, 1 of 17 identified differentially expressed miRNAs, was found to be significantly up-regulated in GDM by quantitative real-time PCR (P < .01), and its expression was closely related with serum estradiol level (P < .05). Furthermore, miR-222 expression was significantly increased in 3T3-L1 adipocytes with a high concentration of 17β-estradiol stimulation (P < .01), whereas the expressions of estrogen receptor (ER)-α protein and insulin-sensitive membrane transporter glucose transporter 4 (GLUT4) protein (P < .01) were markedly reduced. In addition, ERα was shown to be a direct target of miR-222 in 3T3-L1 adipocytes by using the luciferase assay. Finally, antisense oligonucleotides of miR-222 transfection was used to silence miR-222 in 3T3-L1 adipocytes. The results showed that the expressions of ERα and GLUT4, the insulin-stimulated translocation of GLUT4 from the cytoplasm to the cell membrane and glucose uptake in mature adipocytes were dramatically increased (P < .01). In conclusion, miR-222 is a potential regulator of ERα expression in estrogen-induced insulin resistance in GDM and might be a candidate biomarker and therapeutic target for GDM.

scholarly journals Osteopontin Expression in Human and Murine Obesity: Extensive Local Up-Regulation in Adipose Tissue but Minimal Systemic Alterations

Endocrinology ◽  
2007 ◽  
Vol 149 (3) ◽  
pp. 1350-1357 ◽  
Author(s):  
Florian W. Kiefer ◽  
Maximilian Zeyda ◽  
Jelena Todoric ◽  
Joakim Huber ◽  
René Geyeregger ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Plasma Concentrations ◽  
Morbidly Obese ◽  
Low Grade ◽  
Obese Patients ◽  
Multifunctional Protein ◽  
Inflammatory Processes ◽  
Low Grade Inflammation

Obesity is associated with a chronic low-grade inflammation characterized by macrophage infiltration of adipose tissue (AT) that may underlie the development of insulin resistance and type 2 diabetes. Osteopontin (OPN) is a multifunctional protein involved in various inflammatory processes, cell migration, and tissue remodeling. Because these processes occur in the AT of obese patients, we studied in detail the regulation of OPN expression in human and murine obesity. The study included 20 morbidly obese patients and 20 age- and sex-matched control subjects, as well as two models (diet-induced and genetic) of murine obesity. In high-fat diet-induced and genetically obese mice, OPN expression was drastically up-regulated in AT (40 and 80-fold, respectively) but remained largely unaltered in liver (<2-fold). Moreover, OPN plasma concentrations remained unchanged in both murine models of obesity, suggesting a particular local but not systemic importance for OPN. OPN expression was strongly elevated also in the AT of obese patients compared with lean subjects in both omental and sc AT. In addition, we detected three OPN isoforms to be expressed in human AT and, strikingly, an obesity induced alteration of the OPN isoform expression pattern. Analysis of AT cellular fractions revealed that OPN is exceptionally highly expressed in AT macrophages in humans and mice. Moreover, OPN expression in AT macrophages was strongly up-regulated by obesity. In conclusion, our data point toward a specific local role of OPN in obese AT. Therefore, OPN could be a critical regulator in obesity induced AT inflammation and insulin resistance.

scholarly journals Associations between Tissue Visfatin/Nicotinamide, Phosphoribosyltransferase (Nampt), Retinol Binding Protein-4, and Vaspin Concentrations and Insulin Resistance in Morbidly Obese Subjects

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Zeynep Goktas ◽  
Shannon Owens ◽  
Mallory Boylan ◽  
David Syn ◽  
Chwan-Li Shen ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Binding Protein ◽  
Retinol Binding Protein ◽  
Morbidly Obese ◽  
Tissue Samples ◽  
Blood Concentrations ◽  
Nicotinamide Phosphoribosyltransferase ◽  
Retinol Binding Protein 4 ◽  
Obese Subjects

Visfatin/Nampt, vaspin, and retinol binding protein-4 (RBP-4) play an important role in insulin resistance. The objectives of this study were to measure visfatin/Nampt, vaspin, and RBP-4 concentrations in blood, liver, muscle, subcutaneous, omental, and mesenteric adipose tissues in morbidly obese subjects and investigate their relationship to insulin resistance. Blood and tissue samples were collected from 38 morbidly obese subjects during Roux-en-Y surgery. Insulin resistance biomarkers were measured using standard kits. Visfatin/Nampt, vaspin, and RBP-4 gene expression levels in tissues were measured using real-time PCR. Their protein concentrations in blood and tissues were measured using ELISA kits. Diabetic subjects had significantly higher homeostasis model of assessment-insulin resistance and age and lower blood HDL-cholesterol concentrations than nondiabetic and prediabetic subjects. Diabetic and prediabetic subjects had significantly higher blood concentrations of visfatin/Nampt and vaspin than nondiabetic subjects. Liver RBP-4 concentrations were positively associated with blood glucose concentrations. Blood insulin resistance biomarker levels were positively associated with visfatin/Nampt concentrations in omental adipose tissue and liver, and vaspin concentrations in mesenteric adipose tissue. In conclusion, the correlations of visfatin/Nampt, vaspin, and RBP-4 with insulin resistance are tissue dependent.

Ethnic differences in in vitro glyceride synthesis in subcutaneous and omental adipose tissue

2002 ◽  
Vol 283 (5) ◽  
pp. E988-E993 ◽  
Author(s):  
J. F. Bower ◽  
S. Vadlamudi ◽  
H. A. Barakat
Keyword(s):  
Adipose Tissue ◽  
African American ◽  
African American Women ◽  
Ethnic Differences ◽  
American Woman ◽  
Morbidly Obese ◽  
American Women ◽  
Omental Adipose Tissue ◽  
Caucasian Women

Considerable evidence suggests that there are ethnic differences in lipid metabolism between African American and Caucasian women, which may result in increased synthesis of fat in adipose tissue. The purpose of this study was to measure the in vitro rates of [14C]glucose incorporation into the glyceride-glycerol backbone of triglycerides (TG) and diglycerides (DG) in abdominal subcutaneous (SAT) and omental adipose tissue (OAT). Morbidly obese [African American ( n = 15): body mass index (BMI) = 45 ± 2.3; Caucasian ( n = 18): BMI = 51 ± 2.3] and preobese [African American ( n = 7): BMI = 27 ± 1.0; Caucasian ( n = 7): BMI = 25 ± 1.0] women were examined in this study. There were no significant differences in the rates of synthesis of either TG or DG in SAT of either preobese or obese women. On the other hand, both preobese and obese African American women had higher rates of synthesis of TG in OAT compared with their Caucasian counterparts. This increase in TG synthesis in OAT was not due to differences in cell size or rates of reesterification. Thus African American woman have an increased capacity to synthesize TG in OAT compared with Caucasian women, which may contribute to the higher prevalence of obesity in African American women.

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