scholarly journals Impairment of insulin-stimulated GLUT4 translocation in skeletal muscle and adipose tissue in the Tsumura Suzuki obese diabetic mouse: a new genetic animal model of type 2 diabetes

2001 ◽  
pp. 785-790 ◽  
Author(s):  
T Miura ◽  
W Suzuki ◽  
E Ishihara ◽  
I Arai ◽  
H Ishida ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Animal Model ◽  
Adipose Tissue ◽  
Plasma Membrane ◽  
Blood Glucose ◽  
Low Density ◽  
Glut4 Translocation ◽  
Genetic Animal Model

BACKGROUND: In skeletal muscle and adipocytes, insulin-stimulated glucose transport has been known to occur through the translocation of glucose transporter (GLUT) 4 from the intracellular pool to the plasma membrane. The Tsumura Suzuki obese diabetic (TSOD) mouse, a new genetic animal model of type 2 diabetes, develops moderate degrees of obesity and diabetes that are especially apparent in animals more than 11 weeks old. A defect in insulin stimulation of GLUT4 translocation also contributes to the characteristics of type 2 diabetes. OBJECTIVE: To characterize this mouse further, we examined the alteration in insulin-stimulated GLUT4 translocation in the skeletal muscle and adipose tissue. METHODS: For glucose and insulin tolerance tests, the mice were given glucose or insulin and blood samples were collected. After isolation of low-density microsomal membrane and plasma membrane from skeletal muscle and adipose tissue, insulin-stimulated translocation of GLUT4 in these TSOD mice was examined by Western blot. RESULTS AND CONCLUSIONS: TSOD mice showed a significant increase in blood glucose after the glucose load, and exhibited a significantly attenuated decrease in blood glucose concentrations after administration of insulin, compared with that in control Tsumura Suzuki non-obese (TSNO) mice. The insulin-stimulated translocation of GLUT4 from low-density microsomal membranes to plasma membrane was significantly reduced in both skeletal muscle and adipose tissue of TSOD mice. These results indicate that the reduced insulin sensitivity in diabetic TSOD mice is presumably due, at least in part, to the impaired GLUT4 translocation by insulin in both skeletal muscle and adipocytes.

scholarly journals PO-294 Effects of HIIT on FTO protein expression and its relationship with glucose and fat metabolism

2018 ◽  
Vol 1 (5) ◽  
Author(s):  
Chunyan Xu ◽  
Juan Zhao ◽  
Jiayan Duan
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Blood Glucose ◽  
Protein Expression ◽  
Oxidation Rate ◽  
Serum Insulin ◽  
Fat Metabolism

Objective FTO (Fat mass and obesity-associated) is associated with increased risk of obesity and type 2 diabetes incurrence. Studies have shown that the expression of FTO protein in skeletal muscle and adipose tissue is related to the oxidation rate of whole body substrate. With the increase of age, the body's carbohydrate oxidation rate decreases, the fat oxidation rate increases, and at the meanwhile the expression of FTO protein in skeletal muscle decreases and that in adipose increases. HIIT is very helpful for inhibiting obesity, insulin resistance and type 2 diabetes. So the purpose of this study is to investigate the effect of HIIT exercise on the expression of FTO protein in rats and its relationship to glucose and fat metabolism. Methods 20 Male, 3-week-old SD rats were randomly divided into two groups, each group has 10 rats. C group: sedentary; HIIT group: high-intensity intermittent training group (85% ~ 90% VO2max exercise for 6min, 50% VO2max exercise interval 4min, repeated 6 times. 5 times/week ,4 weeks). All subjects were maintained in a free facility with constant temperature of 25°C, light-dark cycle of 12/12 h and free access to water. 48 hours after the last exercise, all samples were taken with an overnight fast. The expression of FTO protein in skeletal muscle and adipose tissue was measured by Western Blot. Serum insulin was tested by ELISA; Estimation of blood glucose was tested by Glucose oxidase method. Results 1.The expression of FTO protein in skeletal muscle was significantly higher than that of group C (P <0.01); The expression of FTO protein in adipose tissue of HIIT group was significantly lower than that of group C (P <0.05); 2. Serum insulin levels of group HIIT was significantly lower than that of group C (p <0.01); And the blood glucose of group HIIT was significantly lower than that of group C (p <0.01). 3. Serum LDL-C of group HIIT was significantly lower than that of group C (p <0.01), and serum HDL-C of group HIIT was significantly higher than that of group C (p <0.01);4. Correlation analysis showed that serum insulin level was negatively correlated with skeletal muscle FTO protein expression (R = -0.454, p < 0.05). Correlation analysis showed that serum LDL-C levels was positively correlated with adipose tissue FTO protein expression (R=0.559, p < 0.05) and serum HDL-C levels was negatively correlated with adipose tissue FTO protein expression (R=-0.474, p < 0.05). Conclusions 1. HIIT can increase the protein expression of FTO in rat skeletal muscle and decrease the expression of FTO protein in adipose tissue; 2. HIIT can regulate glucose metabolism and lipid metabolism in rats; 3. The regulation of glucose metabolism by HIIT may be related to the increase of FTO protein expression in skeletal muscle. The regulation of lipid metabolism may be related to the reduction of FTO protein expression in adipose tissue.

scholarly journals Analysis of gene expression profiles in insulin-sensitive tissues from pre-diabetic and diabetic Zucker diabetic fatty rats

2005 ◽  
Vol 34 (2) ◽  
pp. 299-315 ◽  
Author(s):  
Young Ho Suh ◽  
Younyoung Kim ◽  
Jeong Hyun Bang ◽  
Kyoung Suk Choi ◽  
June Woo Lee ◽  
...  
Keyword(s):  
Gene Expression ◽  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Zucker Diabetic Fatty Rats ◽  
Zdf Rats

Insulin resistance occurs early in the disease process, preceding the development of type 2 diabetes. Therefore, the identification of molecules that contribute to insulin resistance and leading up to type 2 diabetes is important to elucidate the molecular pathogenesis of the disease. To this end, we characterized gene expression profiles from insulin-sensitive tissues, including adipose tissue, skeletal muscle, and liver tissue of Zucker diabetic fatty (ZDF) rats, a well characterized type 2 diabetes animal model. Gene expression profiles from ZDF rats at 6 weeks (pre-diabetes), 12 weeks (diabetes), and 20 weeks (late-stage diabetes) were compared with age- and sex-matched Zucker lean control (ZLC) rats using 5000 cDNA chips. Differentially regulated genes demonstrating > 1.3-fold change at age were identified and categorized through hierarchical clustering analysis. Our results showed that while expression of lipolytic genes was elevated in adipose tissue of diabetic ZDF rats at 12 weeks of age, expression of lipogenic genes was decreased in liver but increased in skeletal muscle of 12 week old diabetic ZDF rats. These results suggest that impairment of hepatic lipogenesis accompanied with the reduced lipogenesis of adipose tissue may contribute to development of diabetes in ZDF rats by increasing lipogenesis in skeletal muscle. Moreover, expression of antioxidant defense genes was decreased in the liver of 12-week old diabetic ZDF rats as well as in the adipose tissue of ZDF rats both at 6 and 12 weeks of age. Cytochrome P450 (CYP) genes were also significantly reduced in 12 week old diabetic liver of ZDF rats. Genes involved in glucose utilization were downregulated in skeletal muscle of diabetic ZDF rats, and the hepatic gluconeogenic gene was upregulated in diabetic ZDF rats. Genes commonly expressed in all three tissue types were also observed. These profilings might provide better fundamental understanding of insulin resistance and development of type 2 diabetes.

scholarly journals MECHANISMS IN ENDOCRINOLOGY: Skeletal muscle lipotoxicity in insulin resistance and type 2 diabetes: a causal mechanism or an innocent bystander?

2017 ◽  
Vol 176 (2) ◽  
pp. R67-R78 ◽  
Author(s):  
Charlotte Brøns ◽  
Louise Groth Grunnet
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Cellular Localization ◽  
Future Research ◽  
Causal Mechanism ◽  
Increased Risk ◽  
Adipose Tissue Expandability

Dysfunctional adipose tissue is associated with an increased risk of developing type 2 diabetes (T2D). One characteristic of a dysfunctional adipose tissue is the reduced expandability of the subcutaneous adipose tissue leading to ectopic storage of fat in organs and/or tissues involved in the pathogenesis of T2D that can cause lipotoxicity. Accumulation of lipids in the skeletal muscle is associated with insulin resistance, but the majority of previous studies do not prove any causality. Most studies agree that it is not the intramuscular lipids per se that causes insulin resistance, but rather lipid intermediates such as diacylglycerols, fatty acyl-CoAs and ceramides and that it is the localization, composition and turnover of these intermediates that play an important role in the development of insulin resistance and T2D. Adipose tissue is a more active tissue than previously thought, and future research should thus aim at examining the exact role of lipid composition, cellular localization and the dynamics of lipid turnover on the development of insulin resistance. In addition, ectopic storage of fat has differential impact on various organs in different phenotypes at risk of developing T2D; thus, understanding how adipogenesis is regulated, the interference with metabolic outcomes and what determines the capacity of adipose tissue expandability in distinct population groups is necessary. This study is a review of the current literature on the adipose tissue expandability hypothesis and how the following ectopic lipid accumulation as a consequence of a limited adipose tissue expandability may be associated with insulin resistance in muscle and liver.

scholarly journals 4126 Intermuscular adipose tissue secretes pro-inflammatory, extracellular matrix, and lipid signals related to insulin resistance and type 2 diabetes

2020 ◽  
Vol 4 (s1) ◽  
pp. 9-9
Author(s):  
Darcy Kahn ◽  
Simona Zarini ◽  
Emily Macias ◽  
Amanda Garfield ◽  
Kathleen Harrison ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Adipose Tissue ◽  
Functional Role ◽  
Vastus Lateralis ◽  
Laparoscopic Bariatric Surgery ◽  
Intermuscular Adipose Tissue

OBJECTIVES/GOALS: Intermuscular adipose tissue (IMAT) has been associated with insulin resistance and type 2 diabetes, yet mechanistic studies addressing the functional role of IMAT are lacking. The aim of this work was to identify novel mechanisms by which IMAT may directly impact skeletal muscle metabolism. METHODS/STUDY POPULATION: We quantified the secretome of IMAT, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) to determine if there are differences between depots in the secretion of cytokines, eicosanoids, FFAs and proteins that influence metabolic function. SAT and VAT biopsies from patients undergoing laparoscopic bariatric surgery and IMAT extracted from vastus lateralis biopsies of individuals with Obesity were cultured for 48 hours in DMEM, and the conditioned media was analyzed using nanoflow HPLC-MS, multiplex ELISAs and LC/MS/MS for proteins, cytokines and eicosanoids/FFA, respectively. RESULTS/ANTICIPATED RESULTS: IMAT secretion of various extracellular matrix proteins (fibrinogen-β, collagenV1a3, fibronectin) was significantly different than VAT and SAT. Pro-inflammatory cytokine secretion of IFNg, TNFa, IL-8 and IL-13 from IMAT was higher than VAT and significantly higher than SAT (p < 0.05). IMAT secretes significantly more pro-inflammatory eicosanoids TXB2 and PGE2 than VAT (p = 0.02, 0.05) and SAT (p = 0.01, 0.04). IMAT and VAT have significantly greater basal lipolysis assessed by FFA release rates compared to SAT (p = 0.01, 0.04). DISCUSSION/SIGNIFICANCE OF IMPACT: These data begin to characterize the disparate secretory properties of SAT, VAT and IMAT and suggest a metabolically adverse secretome of IMAT, that due to its proximity to skeletal muscle may play an important functional role in the pathogenesis of insulin resistance and type 2 diabetes.

scholarly journals Effects of Exenatide and Humalog Mix25 on Fat Distribution, Insulin Sensitivity, and β-Cell Function in Normal BMI Patients with Type 2 Diabetes and Visceral Adiposity

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xinlei Wang ◽  
Xiaoqin Zhao ◽  
Yunjuan Gu ◽  
Xiaohui Zhu ◽  
Tong Yin ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Adipose Tissue ◽  
Blood Glucose ◽  
Insulin Sensitivity ◽  
Magnetic Resonance ◽  
Cell Function ◽  
Visceral Adiposity ◽  
Fibroblast Growth Factor 21 ◽  
Resonance Spectroscopy

In China, most normal BMI (body mass index of ≥18.5 to <25 kg/m2) adults with type 2 diabetes (T2DM) exhibit visceral adiposity. This study compared the effects of exenatide and humalog Mix25 on normal BMI patients with T2DM and visceral adiposity. A total of 95 patients were randomized to receive either exenatide or humalog Mix25 treatment for 24 weeks. Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were quantified by magnetic resonance imaging (MRI) and liver fat content (LFC) by liver proton magnetic resonance spectroscopy (1H MRS). Each patient’s weight, waist circumference, BMI, blood glucose, insulin sensitivity, pancreatic β-cell function, and fibroblast growth factor 21 (FGF-21) levels were measured. Data from 81 patients who completed the study (40 and 41 in the exenatide and humalog Mix25 groups, respectively) were analysed. The change in 2 h plasma blood glucose was greater in the exenatide group (P=0.039). HOMA-IR and MBCI improved significantly after exenatide therapy (P<0.01, P=0.045). VAT and LFC decreased in both groups (P<0.01 for all) but to a greater extent in the exenatide group, while SAT only decreased with exenatide therapy (P<0.01). FGF-21 levels declined more in the exenatide group (P<0.01), but were positively correlated with VAT in the entire cohort before (r=0.244, P=0.043) and after (r=0.290, P=0.016) the intervention. The effects of exenatide on glycaemic metabolism, insulin resistance, pancreatic β-cell function, and fat deposition support its administration to normal BMI patients with T2DM and visceral adiposity.

Effect of Sleeve Gastrectomy on Angiogenesis and Adipose Tissue Health in an Obese Animal Model of Type 2 Diabetes

2019 ◽  
Vol 29 (9) ◽  
pp. 2942-2951 ◽  
Author(s):  
Hans Eickhoff ◽  
Tiago Rodrigues ◽  
Inês Neves ◽  
Daniela Marques ◽  
Diana Ribeiro ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Animal Model ◽  
Adipose Tissue ◽  
Sleeve Gastrectomy ◽  
Obese Animal

Loss of HIF-1α impairs GLUT4 translocation and glucose uptake by the skeletal muscle cells

2014 ◽  
Vol 306 (9) ◽  
pp. E1065-E1076 ◽  
Author(s):  
Hidemitsu Sakagami ◽  
Yuichi Makino ◽  
Katsutoshi Mizumoto ◽  
Tsubasa Isoe ◽  
Yasutaka Takeda ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Intracellular Signaling ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Glut4 Translocation

Defects in glucose uptake by the skeletal muscle cause diseases linked to metabolic disturbance such as type 2 diabetes. The molecular mechanism determining glucose disposal in the skeletal muscle in response to cellular stimuli including insulin, however, remains largely unknown. The hypoxia-inducible factor-1α (HIF-1α) is a transcription factor operating in the cellular adaptive response to hypoxic conditions. Recent studies have uncovered pleiotropic actions of HIF-1α in the homeostatic response to various cellular stimuli, including insulin under normoxic conditions. Thus we hypothesized HIF-1α is involved in the regulation of glucose metabolism stimulated by insulin in the skeletal muscle. To this end, we generated C2C12myocytes in which HIF-1α is knocked down by short-hairpin RNA and examined the intracellular signaling cascade and glucose uptake subsequent to insulin stimulation. Knockdown of HIF-1α expression in the skeletal muscle cells resulted in abrogation of insulin-stimulated glucose uptake associated with impaired mobilization of glucose transporter 4 (GLUT4) to the plasma membrane. Such defect seemed to be caused by reduced phosphorylation of the protein kinase B substrate of 160 kDa (AS160). AS160 phosphorylation and GLUT4 translocation by AMP-activated protein kinase activation were abrogated as well. In addition, expression of the constitutively active mutant of HIF-1α (CA-HIF-1α) or upregulation of endogenous HIF-1α in C2C12cells shows AS160 phosphorylation comparable to the insulin-stimulated level even in the absence of insulin. Accordingly GLUT4 translocation was increased in the cells expressing CA-HIF1α. Taken together, HIF-1α is a determinant for GLUT4-mediated glucose uptake in the skeletal muscle cells thus as a possible target to alleviate impaired glucose metabolism in, e.g., type 2 diabetes.

scholarly journals Association between Interleukin-15 and Obesity: Interleukin-15 as a Potential Regulator of Fat Mass

2008 ◽  
Vol 93 (11) ◽  
pp. 4486-4493 ◽  
Author(s):  
Anders Rinnov Nielsen ◽  
Pernille Hojman ◽  
Christian Erikstrup ◽  
Christian Philip Fischer ◽  
Peter Plomgaard ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Fat Mass ◽  
Negative Association ◽  
Tissue Mass ◽  
Adipose Tissue Mass ◽  
Interleukin 15 ◽  
Total Fat

Objective: IL-15 decreases lipid deposition in preadipocytes and decreases the mass of white adipose tissue in rats, indicating that IL-15 may take part in regulating this tissue. IL-15 is expressed in human skeletal muscle and skeletal muscle may be a source of plasma IL-15 and in this way regulate adipose tissue mass. Design: The relation between skeletal muscle IL-15 mRNA expression, plasma IL-15, and adipose tissue mass was studied in 199 humans divided into four groups on the basis of obesity and type 2 diabetes. Furthermore, using a DNA electrotransfer model, we assessed the effect of IL-15 overexpression in skeletal muscle of mice. Results: In humans, multiple regression analysis showed a negative association between plasma IL-15 and total fat mass (P &lt; 0.05), trunk fat mass (P &lt; 0.01), and percent fat mass (P &lt; 0.05), independent of type 2 diabetes. Negative associations were also found between muscle IL-15 mRNA and obesity parameters. IL-15 overexpression in skeletal muscle of mice reduced trunk fat mass but not sc fat mass. Conclusions: Our results indicate that IL-15 may be a regulator of trunk fat mass.

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