Toona Sinensis ameliorates insulin resistance via AMPK and PPARγ pathways

2015 ◽  
Vol 6 (6) ◽  
pp. 1855-1864 ◽  
Author(s):  
Hung-Wen Liu ◽  
Wen-Cheng Huang ◽  
Wen-Jen Yu ◽  
Sue-Joan Chang
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Uptake ◽  
C2c12 Myotubes ◽  
High Fat ◽  
Toona Sinensis

Toona sinensis improves insulin sensitivity in high-fat-fed mice and directly stimulates glucose uptake via AMPKα in C2C12 myotubes.

Saturated, but not n-6 polyunsaturated, fatty acids induce insulin resistance: role of intramuscular accumulation of lipid metabolites

2006 ◽  
Vol 100 (5) ◽  
pp. 1467-1474 ◽  
Author(s):  
Jong Sam Lee ◽  
Srijan K. Pinnamaneni ◽  
Su Ju Eo ◽  
In Ho Cho ◽  
Jae Hwan Pyo ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Fatty Acids ◽  
Insulin Sensitivity ◽  
Polyunsaturated Fatty Acids ◽  
Glucose Uptake ◽  
High Fat ◽  
Insulin Resistant ◽  
L6 Myotubes ◽  
Lipid Metabolites

Consumption of a Western diet rich in saturated fats is associated with obesity and insulin resistance. In some insulin-resistant phenotypes this is associated with accumulation of skeletal muscle fatty acids. We examined the effects of diets high in saturated fatty acids (Sat) or n-6 polyunsaturated fatty acids (PUFA) on skeletal muscle fatty acid metabolite accumulation and whole-body insulin sensitivity. Male Sprague-Dawley rats were fed a chow diet (16% calories from fat, Con) or a diet high (53%) in Sat or PUFA for 8 wk. Insulin sensitivity was assessed by fasting plasma glucose and insulin and glucose tolerance via an oral glucose tolerance test. Muscle ceramide and diacylglycerol (DAG) levels and triacylglycerol (TAG) fatty acids were also measured. Both high-fat diets increased plasma free fatty acid levels by 30%. Compared with Con, Sat-fed rats were insulin resistant, whereas PUFA-treated rats showed improved insulin sensitivity. Sat caused a 125% increase in muscle DAG and a small increase in TAG. Although PUFA also resulted in a small increase in DAG, the excess fatty acids were primarily directed toward TAG storage (105% above Con). Ceramide content was unaffected by either high-fat diet. To examine the effects of fatty acids on cellular lipid storage and glucose uptake in vitro, rat L6 myotubes were incubated for 5 h with saturated and polyunsaturated fatty acids. After treatment of L6 myotubes with palmitate (C16:0), the ceramide and DAG content were increased by two- and fivefold, respectively, concomitant with reduced insulin-stimulated glucose uptake. In contrast, treatment of these cells with linoleate (C18:2) did not alter DAG, ceramide levels, and glucose uptake compared with controls (no added fatty acids). Both 16:0 and 18:2 treatments increased myotube TAG levels (C18:2 vs. C16:0, P < 0.05). These results indicate that increasing dietary Sat induces insulin resistance with concomitant increases in muscle DAG. Diets rich in n-6 PUFA appear to prevent insulin resistance by directing fat into TAG, rather than other lipid metabolites.

scholarly journals Citrus junosTanaka Peel Extract Exerts Antidiabetic Effects via AMPK and PPAR-γbothIn VitroandIn Vivoin Mice Fed a High-Fat Diet

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Sung Hee Kim ◽  
Haeng Jeon Hur ◽  
Hye Jeong Yang ◽  
Hyun Jin Kim ◽  
Min Jung Kim ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Total Cholesterol ◽  
Glucose Uptake ◽  
High Fat Diet ◽  
Ethanol Extract ◽  
Liver Fat ◽  
C2c12 Myotubes ◽  
Dependent Manner ◽  
High Fat ◽  
Citrus Junos

The antidiabetic effect of theCitrus junosTanaka (also known as yuja or yuzu) was examined. Ethanol extract of yuja peel (YPEE) significantly stimulated 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG) uptake in C2C12 myotubes. However, ethanol extract of yuja pulp (YpEE) and water extract of yuja peel (YPWE) or pulp (YpWE) did not stimulate glucose uptake. In addition, peroxisome proliferator-activated receptor gamma (PPAR-γ) and AMP-activated protein kinase (AMPK) activities were increased by YPEE in a dose-dependent manner. Pretreatment of AMPK inhibitor decreased the glucose uptake stimulated by YPEE in C2C12 myotubes. We confirmed the anti-diabetic effect of YPEE in mice fed a high fat-diet (HFD). Compared with control mice on a normal diet (ND), these mice showed increased body weight, liver fat, insulin resistance, triacylglycerol (TG), and total cholesterol content. Addition of 5% YPEE significantly reduced the weight gain and rise in liver fat content, serum triacylglycerol (TG), total cholesterol, and insulin resistance found in mice fed a high-fat diet (HFD). Moreover, YPEE reduced the secretion of HFD-induced adipocytokines such as leptin and resistin. YPEE also resulted in increased phosphorylation of AMPK in muscle tissues. These results suggest that ethanol extract of yuja peel exerts anti-diabetic effects via AMPK and PPAR-γin both cell culture and mouse models.

scholarly journals miR-146a regulates insulin sensitivity via NPR3

2020 ◽  
Author(s):  
Julian Roos ◽  
Meike Dahlhaus ◽  
Jan-Bernd Funcke ◽  
Monika Kustermann ◽  
Gudrun Strauss ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Uptake ◽  
High Fat Diet ◽  
Metabolic Diseases ◽  
De Novo ◽  
Liver Steatosis ◽  
De Novo Lipogenesis ◽  
Loss Of Function ◽  
High Fat

AbstractThe pathogenesis of obesity-related metabolic diseases has been linked to the inflammation of white adipose tissue (WAT), but the molecular interconnections are still not fully understood. MiR-146a controls inflammatory processes by suppressing pro-inflammatory signaling pathways. The aim of this study was to characterize the role of miR-146a in obesity and insulin resistance. MiR-146a−/− mice were subjected to a high-fat diet followed by metabolic tests and WAT transcriptomics. Gain- and loss-of-function studies were performed using human Simpson–Golabi–Behmel syndrome (SGBS) adipocytes. Compared to controls, miR-146a−/− mice gained significantly more body weight on a high-fat diet with increased fat mass and adipocyte hypertrophy. This was accompanied by exacerbated liver steatosis, insulin resistance, and glucose intolerance. Likewise, adipocytes transfected with an inhibitor of miR-146a displayed a decrease in insulin-stimulated glucose uptake, while transfecting miR-146a mimics caused the opposite effect. Natriuretic peptide receptor 3 (NPR3) was identified as a direct target gene of miR-146a in adipocytes and CRISPR/Cas9-mediated knockout of NPR3 increased insulin-stimulated glucose uptake and enhanced de novo lipogenesis. In summary, miR-146a regulates systemic and adipocyte insulin sensitivity via downregulation of NPR3.

scholarly journals Loss of hnRNP A1 in murine skeletal muscle exacerbates high-fat diet-induced onset of insulin resistance and hepatic steatosis

2019 ◽  
Vol 12 (4) ◽  
pp. 277-290 ◽  
Author(s):  
Mingxia Zhao ◽  
Lihong Shen ◽  
Zijun Ouyang ◽  
Manru Li ◽  
Guoliang Deng ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Hepatic Steatosis ◽  
Muscle Tissue ◽  
High Fat Diet ◽  
Glycogen Synthesis ◽  
C2c12 Myotubes ◽  
Hnrnp A1 ◽  
High Fat

Abstract Impairment of glucose (Glu) uptake and storage by skeletal muscle is a prime risk factor for the development of metabolic diseases. Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is a highly abundant RNA-binding protein that has been implicated in diverse cellular functions. The aim of this study was to investigate the function of hnRNP A1 on muscle tissue insulin sensitivity and systemic Glu homeostasis. Our results showed that conditional deletion of hnRNP A1 in the muscle gave rise to a severe insulin resistance phenotype in mice fed a high-fat diet (HFD). Conditional knockout mice fed a HFD showed exacerbated obesity, insulin resistance, and hepatic steatosis. In vitro interference of hnRNP A1 in C2C12 myotubes impaired insulin signal transduction and inhibited Glu uptake, whereas hnRNP A1 overexpression in C2C12 myotubes protected against insulin resistance induced by supraphysiological concentrations of insulin. The expression and stability of glycogen synthase (gys1) mRNA were also decreased in the absence of hnRNP A1. Mechanistically, hnRNP A1 interacted with gys1 and stabilized its mRNA, thereby promoting glycogen synthesis and maintaining the insulin sensitivity in muscle tissue. Taken together, our findings are the first to show that reduced expression of hnRNP A1 in skeletal muscle affects the metabolic properties and systemic insulin sensitivity by inhibiting glycogen synthesis.

scholarly journals Human Resistin Inhibits Myogenic Differentiation and Induces Insulin Resistance in Myocytes

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Chun Hua Sheng ◽  
Zhen Wu Du ◽  
Yang Song ◽  
Xiao Dong Wu ◽  
Yu Cheng Zhang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Cell Proliferation ◽  
Insulin Sensitivity ◽  
Glucose Uptake ◽  
Myogenic Differentiation ◽  
C2c12 Cells ◽  
C2c12 Myotubes ◽  
Mrna Levels ◽  
Uptake Ratio ◽  
Human Resistin

This study is aimed to investigate the effect of human resistin on myocyte differentiation and insulin resistance. The human resistin eukaryotic expression vector was stable transfected into C2C12 myocyte cells and was transiently transfected into COS7 cells. The effects of human resistin on cell proliferation, cell cycle, and myogenic differentiation of C2C12 cells were examined. Glucose uptake assays was performed on C2C12 myotubes by using [3H] 2-deoxy-D-glucose. The mRNA levels of insulin receptor (IR) and glucose transporter 4 (GLUT4) were evaluated by semiquantitative RT-PCR. Results showed by the C2C12 cells transfected with human resistin gene compared with that without transfecting gene are as follows: (1) cell proliferation was significantly promoted, (2) after inducing differentiation, the myotube’s diameters and expression of desmin and myoglobin decreased, and (3) glucose uptake ratio was lowered and expression of IR and GLUT4 decreased. However, there was no significant difference in the glucose uptake ratio between C2C12 myotubes treated with a human resistin conditioned medium of COS7 cells and treated with control medium. These results suggest that maybe human resistin has not a direct role on insulin sensitivity of myocytes. However, maybe it impaired the insulin sensitivity of myocytes through suppressing myogenesis and stimulating proliferation of myoblasts.

scholarly journals Impaired adipose expansion caused by liver X receptor activation is associated with insulin resistance in mice fed a high-fat diet

2017 ◽  
Vol 58 (3) ◽  
pp. 141-154 ◽  
Author(s):  
Yueting Dong ◽  
Zhiye Xu ◽  
Ziyi Zhang ◽  
Xueyao Yin ◽  
Xihua Lin ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Uptake ◽  
High Fat Diet ◽  
Insulin Response ◽  
Receptor Activation ◽  
Metabolic Effects ◽  
Whole Body ◽  
High Fat ◽  
Epididymal Fat

Liver X receptors (LXR) are deemed as potential drug targets for atherosclerosis, whereas a role in adipose tissue expansion and its relation to insulin sensitivity remains unclear. To assess the metabolic effects of LXR activation by the dual LXRα/β agonist T0901317, C57BL/6 mice fed a high-fat diet (HFD) were treated with T0901317 (30 mg/kg once daily by intraperitoneal injection) for 3 weeks. Differentiated 3T3-L1 adipocytes were used for analysing the effect of T0901317 on glucose uptake. The following results were obtained from this study. T0901317 reduced fat mass, accompanied by a massive fatty liver and lower serum adipokine levels in HFD mice. Increased adipocyte apoptosis was found in epididymal fat of T0901317-treated HFD mice. In addition, T0901317 treatment promoted basal lipolysis, but blunted the anti-lipolytic action of insulin. Furthermore, LXR activation antagonised PPARγ target genes in epididymal fat and PPARγ-PPRE-binding activity in 3T3-L1 adipocytes. Although the glucose tolerance was comparable to that in HFD mice, the insulin response during IPGTT was significantly higher and the insulin tolerance was significantly impaired in T0901317-treated HFD mice, indicating decreased insulin sensitivity by T0901317 administration, and which was further supported by impaired insulin signalling found in epididymal fat and decreased insulin-induced glucose uptake in 3T3-L1 adipocytes by T0901317 administration. In conclusion, these findings reveal that LXR activation impairs adipose expansion by increasing adipocyte apoptosis, lipolysis and antagonising PPARγ-mediated transcriptional activity, which contributes to decreased insulin sensitivity in whole body. The potential of LXR activation being a therapeutic target for atherosclerosis might be limited by the possibility of exacerbating insulin resistance.

Time course of insulin resistance associated with feeding dogs a high-fat diet

1997 ◽  
Vol 272 (1) ◽  
pp. E147-E154 ◽  
Author(s):  
A. P. Rocchini ◽  
P. Marker ◽  
T. Cervenka
Keyword(s):  
Insulin Resistance ◽  
Blood Pressure ◽  
Glucose Uptake ◽  
Dose Response ◽  
High Fat Diet ◽  
Time Course ◽  
Rapid Development ◽  
Diet Group ◽  
Whole Body ◽  
High Fat

The current study evaluated both the time course of insulin resistance associated with feeding dogs a high-fat diet and the relationship between the development of insulin resistance and the increase in blood pressure that also occurs. Twelve adult mongrel dogs were chronically instrumented and randomly assigned to either a control diet group (n = 4) or a high-fat diet group (n = 8). Insulin resistance was assessed by a weekly, single-dose (2 mU.kg-1.min-1) euglycemic-hyperinsulinemic clamp on all dogs. Feeding dogs a high-fat diet was associated with a 3.7 +/- 0.5 kg increase in body weight, a 20 +/- 4 mmHg increase in mean blood pressure, a reduction in insulin-mediated glucose uptake [(in mumol-kg-1.min-1) decreasing from 72 +/- 6 before to 49 +/- 7 at 1 wk, 29 +/- 3 at 3 wk, and 30 +/- 2 at 6 wk of the high-fat diet, P < 0.01]. and a reduced insulin-mediated increase in cardiac output. In eight dogs (4 high fat and 4 control), the dose-response relationship of insulin-induced glucose uptake also was studied. The whole body glucose uptake dose-response curve was shifted to the right, and the rate of maximal whole body glucose uptake was significantly decreased (P < 0.001). Finally, we observed a direct relationship between the high-fat diet-induced weekly increase in mean arterial pressure and the degree to which insulin resistance developed. In summary, the current study documents that feeding dogs a high-fat diet causes the rapid development of insulin resistance that is the result of both a reduced sensitivity and a reduced responsiveness to insulin.

A1 adenosine receptor partial agonist lowers plasma FFA and improves insulin resistance induced by high-fat diet in rodents

2007 ◽  
Vol 292 (5) ◽  
pp. E1358-E1363 ◽  
Author(s):  
Arvinder K. Dhalla ◽  
Mei Yee Wong ◽  
Peter J. Voshol ◽  
Luiz Belardinelli ◽  
Gerald M. Reaven
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Adenosine Receptor ◽  
Infusion Rate ◽  
Glucose Infusion ◽  
Glucose Infusion Rate ◽  
Oral Glucose ◽  
Acute Administration ◽  
High Fat ◽  
Adenosine Receptor Agonist

There is substantial evidence in the literature that elevated plasma free fatty acids (FFA) play a role in the pathogenesis of type 2 diabetes. CVT-3619 is a selective partial A1 adenosine receptor agonist that inhibits lipolysis and lowers circulating FFA. The present study was undertaken to determine the effect of CVT-3619 on insulin resistance induced by high-fat (HF) diet in rodents. HF diet feeding to rats for 2 wk caused a significant increase in insulin, FFA, and triglyceride (TG) concentrations compared with rats fed chow. CVT-3619 (1 mg/kg) caused a time-dependent decrease in fasting insulin, FFA, and TG concentrations. Acute administration of CVT-3619 significantly lowered the insulin response, whereas glucose response was not different with an oral glucose tolerance test. Treatment with CVT-3619 for 2 wk resulted in significant lowering of FFA, TG, and insulin concentrations in rats on HF diet. To determine the effect of CVT-3619 on insulin sensitivity, hyperinsulinemic euglycemic clamp studies were performed in C57BL/J6 mice fed HF diet for 12 wk. Glucose infusion rate was decreased significantly in HF mice compared with chow-fed mice. CVT-3619 treatment 15 min prior to the clamp study significantly ( P < 0.01) increased glucose infusion rate to values similar to that for chow-fed mice. In conclusion, CVT-3619 treatment lowers FFA and TG concentrations and improves insulin sensitivity in rodent models of insulin resistance.

14-Deoxy-11,12-Didehydroandrographolide Ameliorates Glucose Intolerance Enhancing the LKB1/AMPKα/TBC1D1/GLUT4 Signaling Pathway and Inducing GLUT4 Expression in Myotubes and Skeletal Muscle of Obese Mice

2021 ◽  
pp. 1-19
Author(s):  
Chih-Chieh Chen ◽  
Chong-Kuei Lii ◽  
Chia-Wen Lo ◽  
Yi-Hsueh Lin ◽  
Ya-Chen Yang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Signaling Pathway ◽  
Nuclear Translocation ◽  
Time Dependent ◽  
Antidiabetic Activity ◽  
C2c12 Myotubes ◽  
Dependent Manner ◽  
Compound C

14-Deoxy-11,12-didehydroandrographolide (deAND), a bioactive component of Andrographis paniculata, has antidiabetic activity. AMP-activated protein kinase (AMPK) regulates glucose transport and ameliorates insulin resistance. The aim of the present study was to investigate whether activation of AMPK is involved in the mechanism by which deAND ameliorates insulin resistance in muscles. deAND amounts up to 40 [Formula: see text]M dose-dependently activated phosphorylation of AMPK[Formula: see text] and TBC1D1 in C2C12 myotubes. In addition, deAND significantly activated phosphorylation of LKB1 at 6 h after treatment, and this activation was maintained up to 48 h. deAND increased glucose uptake at 18 h after treatment, and this increase was time dependent up to 72 h. Compound C, an inhibitor of AMPK, suppressed deAND-induced phosphorylation of AMPK[Formula: see text] and TBC1D1 and reversed the effect on glucose uptake. In addition, the expression of GLUT4 mRNA and protein in C2C12 myotubes was up-regulated by deAND in a time-dependent manner. Promotion of GLUT4 gene transcription was verified by a pGL3-GLUT4 (837 bp) reporter assay. deAND also increased the nuclear translocation of MEF-2A and PPAR[Formula: see text]. After 16 weeks of feeding, the high-fat diet (HFD) inhibited phosphorylation of AMPK[Formula: see text] and TBC1D1 in skeletal muscle of obese C57BL/6JNarl mice, and deactivation of AMPK[Formula: see text] and TBC1D1 by the HFD was abolished by deAND supplementation. Supplementation with deAND significantly promoted membrane translocation of GLUT4 compared with the HFD group. Supplementation also significantly increased GLUT4 mRNA and protein expression in skeletal muscle compared with the HFD group. The hypoglycemic effects of deAND are likely associated with activation of the LKB1/AMPK[Formula: see text]/TBC1D1/GLUT4 signaling pathway and stimulation of MEF-2A- and PPAR[Formula: see text]-dependent GLUT4 gene expression, which account for the glucose uptake into skeletal muscle and lower blood glucose levels.

Abstract 1361: Leukocyte Antigen-Related Phosphatase Regulates Insulin Sensitivity by Interaction with Snapin

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Aleksandr E Vendrov ◽  
Igor Tchivilev ◽  
Xi-Lin Niu ◽  
Juxiang Li ◽  
Marschall S Runge ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Uptake ◽  
Glycogen Synthase ◽  
Serine Phosphorylation ◽  
Snare Complex ◽  
Vascular Pathology ◽  
Wild Type ◽  
Membrane Translocation ◽  
Leukocyte Antigen

Several protein tyrosine phosphatases including leukocyte antigen-related (LAR) phosphatase have been implicated in insulin resistance, which is a risk factor for atherosclerosis. We showed previously that LAR negatively regulates insulin-like growth factor-1 (IGF1) signaling in vascular smooth muscle cells (VSMC) leading to increased proliferation and migration. Absence of LAR also enhanced neointima formation in response to arterial injury in mice. However, the role of LAR-modulated signaling in the development of insulin resistance has not been elucidated. Here, we investigated the function of LAR in regulating glucose uptake and insulin sensitivity. We identified snapin, a SNARE-associated protein involved in glucose transporter Glut4 vesicle fusion with plasma membrane, as a LAR-interacting protein using a yeast two-hybrid screen. IGF1-induced serine phosphorylation of snapin, its translocation to membrane and association with SNARE complex were enhanced in VSMC lacking LAR. Similarly, PI3K-PDK1-PKCζ signaling pathway was more active in LAR-/- cells after IGF1 treatment. This resulted in enhanced Glut4 activation, its membrane translocation and association with snapin. Glut4 membrane translocation and association with snapin after IGF1 treatment were impaired in snapin+/− VSMC. IGF1 treatment also increased serine phosphorylation of GSK3 β in LAR−/− VSMC leading to increased activation of glycogen synthase. Consistent with this, enhanced glucose uptake was observed in LAR−/− VSMC compared to wild-type cells after IGF1 treatment. Basal and IGF1-induced glucose uptake were significantly lower in snapin+/− VSMC than in wild-type cells. Snapin+/− mice had higher levels of blood glucose, lower quantitative insulin sensitivity check index (QUICKI) and impaired response to insulin in insulin tolerance test (ITT) compared to wild-type mice. Decrease of QUICKI and impairment of IIT were more pronounced in snapin+/− mice fed a high-fat diet. In addition, Doppler ultrasonography indicated increased arterial stiffness in snapin+/− mice. Together, these data indicate that LAR negatively regulates snapin phosphorylation which in turn affects glucose uptake leading to the development of insulin resistance and vascular pathology.

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