scholarly journals Resveratrol metabolites ameliorate insulin resistance in HepG2 hepatocytes by modulating IRS-1/AMPK

RSC Advances ◽  
2018 ◽  
Vol 8 (63) ◽  
pp. 36034-36042 ◽  
Author(s):  
Wendi Teng ◽  
Wenjing Yin ◽  
Liang Zhao ◽  
Changwei Ma ◽  
Jiaqiang Huang ◽  
...  

RSV metabolites R3G and R4G protected HepG2 cell from insulin resistance by improving glucose uptake and glycogen synthesis, along with inhibiting ROS generation and modulating the RS-1/AMPK signaling pathway.

2018 ◽  
Vol 9 (5) ◽  
pp. 2829-2839 ◽  
Author(s):  
Zhiheng Ren ◽  
Zhifei Xie ◽  
Danni Cao ◽  
Mufeng Gong ◽  
Lei Yang ◽  
...  

The mechanism of C-PC in improving glucose homoeostasis is to activate the IRS/PI3 K/Akt and SIRT1/LKB1/AMPK signaling pathway in insulin resistant hepatocytes.


2021 ◽  
Vol 11 (9) ◽  
pp. 1812-1817
Author(s):  
Jingjing Zhou ◽  
Wenjuan Zhu ◽  
Zheng Mao ◽  
Zhen Li ◽  
Xiaoqin Li ◽  
...  

Background: The objective of the research was to investigate the roles of miR-4458 in the regulation of insulin resistance in hepatic cells and to explore the underlying molecular mechanisms. Methods: The blood samples were collected from the T2D patients and the health controls, and the liver tissues were collected from the DM and control rats. The relationship between IGF1R and miR-4458 was predicted by TargetScan and verified by the dual luciferase reporter gene system. qRT-PCR was used to measure the mRNA expression of miR-4458, IGF1R, G6Pase and PEPCK. The protein expression of IGF1R, p-AKT and AKT were measured by Western blot analysis. The rat insulin ELISA Kit and glucose Uptake Colorimteric Assay Kit were used to determine the level of serum insulin and the glucose uptake. Results: miR-4458 was high expressed in T2D patients. We predicted and verified that IGF1R was a direct target of miR-4458, and the mRNA expression of IGF1R was reduced in type 2 diabetes patients. We established the diabetes model (DM) and IR HepG2 cell model, and found that the blood glucose and serum insulin levels were significantly elevated in the DM group. miR-4458 expression was up-regulated, while the expression of IGF1R and p-AKT, and p-AKT/AKT ratio were reduced in the DM group and IR HepG2 cell model. miR-4458 inhibitor and IGF1R-siRNA significantly decreased the expression of miR-4458 and IGF1R respectively. In comparison with IR+inhibitor control group, miR-4458 inhibitor increased 2-DG6P content, IGF1R expression, p-AKT expression and p-AKT/AKT ratio, reduced the expression of G6Pase and PEPCK, and all the effects were reversed by down-regulating IGF1R. Conclusion: miR-4458 regulated the insulin resistance in hepatic cells by regulating the IGF1R/PI3K/AKT signal pathway, which will be a potential target for the treatment of diabetes.


Author(s):  
Chih-Chieh Chen ◽  
Chong-Kuei Lii ◽  
Chia-Wen Lo ◽  
Yi-Hsueh Lin ◽  
Ya-Chen Yang ◽  
...  

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.


1997 ◽  
Vol 272 (2) ◽  
pp. E288-E296 ◽  
Author(s):  
J. K. Kim ◽  
J. H. Youn

To determine whether an impairment of intracellular glucose metabolism causes insulin resistance, we examined the effects of suppression of glycolysis or glycogen synthesis on whole body and skeletal muscle insulin-stimulated glucose uptake during 450-min hyperinsulinemic euglycemic clamps in conscious rats. After the initial 150 min to attain steady-state insulin action, animals received an additional infusion of saline, Intralipid and heparin (to suppress glycolysis), or amylin (to suppress glycogen synthesis) for up to 300 min. Insulin-stimulated whole body glucose fluxes were constant with saline infusion (n = 7). In contrast, Intralipid infusion (n = 7) suppressed glycolysis by approximately 32%, and amylin infusion (n = 7) suppressed glycogen synthesis by approximately 45% within 30 min after the start of the infusions (P < 0.05). The suppression of metabolic fluxes increased muscle glucose 6-phosphate levels (P < 0.05), but this did not immediately affect insulin-stimulated glucose uptake due to compensatory increases in other metabolic fluxes. Insulin-stimulated whole body glucose uptake started to decrease at approximately 60 min and was significantly decreased by approximately 30% at the end of clamps (P < 0.05). Similar patterns of changes in insulin-stimulated glucose fluxes were observed in individual skeletal muscles. Thus the suppression of intracellular glucose metabolism caused decreases in insulin-stimulated glucose uptake through a cellular adaptive mechanism in response to a prolonged elevation of glucose 6-phosphate rather than the classic mechanism involving glucose 6-phosphate inhibition of hexokinase.


2007 ◽  
Vol 293 (5) ◽  
pp. E1358-E1364 ◽  
Author(s):  
Andrew J. Hoy ◽  
Clinton R. Bruce ◽  
Anna Cederberg ◽  
Nigel Turner ◽  
David E. James ◽  
...  

Hyperglycemia is a defining feature of Type 1 and 2 diabetes. Hyperglycemia also causes insulin resistance, and our group (Kraegen EW, Saha AK, Preston E, Wilks D, Hoy AJ, Cooney GJ, Ruderman NB. Am J Physiol Endocrinol Metab Endocrinol Metab 290: E471–E479, 2006) has recently demonstrated that hyperglycemia generated by glucose infusion results in insulin resistance after 5 h but not after 3 h. The aim of this study was to investigate possible mechanism(s) by which glucose infusion causes insulin resistance in skeletal muscle and in particular to examine whether this was associated with changes in insulin signaling. Hyperglycemia (∼10 mM) was produced in cannulated male Wistar rats for up to 5 h. The glucose infusion rate required to maintain this hyperglycemia progressively lessened over 5 h (by 25%, P < 0.0001 at 5 h) without any alteration in plasma insulin levels consistent with the development of insulin resistance. Muscle glucose uptake in vivo (44%; P < 0.05) and glycogen synthesis rate (52%; P < 0.001) were reduced after 5 h compared with after 3 h of infusion. Despite these changes, there was no decrease in the phosphorylation state of multiple insulin signaling intermediates [insulin receptor, Akt, AS160 (Akt substrate of 160 kDa), glycogen synthase kinase-3β] over the same time course. In isolated soleus strips taken from control or 1- or 5-h glucose-infused animals, insulin-stimulated 2-deoxyglucose transport was similar, but glycogen synthesis was significantly reduced in the 5-h muscle sample (68% vs. 1-h sample; P < 0.001). These results suggest that the reduced muscle glucose uptake in rats after 5 h of acute hyperglycemia is due more to the metabolic effects of excess glycogen storage than to a defect in insulin signaling or glucose transport.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Caiping Lu ◽  
Hanying Xing ◽  
Linquan Yang ◽  
Kaiting Chen ◽  
Linyi Shu ◽  
...  

Diabetes mellitus is highly prevalent worldwide. High-fat-diet (HFD) consumption can lead to liver fat accumulation, impair hepatic glycometabolism, and cause insulin resistance and the development of diabetes. Resveratrol has been shown to improve the blood glucose concentration of diabetic mice, but its effect on the abnormal hepatic glycometabolism induced by HFD-feeding and the mechanism involved are unknown. In this study, we determined the effects of resveratrol on the insulin resistance of high-fat-diet-fed mice and a hepatocyte model by measuring serum biochemical indexes, key indicators of glycometabolism, glucose uptake, and glycogen synthesis in hepatocytes. We found that resveratrol treatment significantly ameliorated the HFD-induced abnormalities in glucose metabolism in mice, increased glucose absorption and glycogen synthesis, downregulated protein phosphatase 2A (PP2A) and activated Ca2+/CaM-dependent protein kinase kinase β (CaMKKβ), and increased the phosphorylation of AMP-activated protein kinase (AMPK). In insulin-resistant HepG2 cells, the administration of a PP2A activator or CaMKKβ inhibitor attenuated the effects of resveratrol, but the administration of an AMPK inhibitor abolished the effects of resveratrol. Resveratrol significantly ameliorates abnormalities in glycometabolism induced by HFD-feeding and increases glucose uptake and glycogen synthesis in hepatocytes. These effects are mediated through the activation of AMPK by PP2A and CaMKKβ.


2020 ◽  
Author(s):  
Min Liu ◽  
Lujing Wang ◽  
Xigan Li ◽  
Yucui Wu ◽  
Fei Yin ◽  
...  

Abstract Background: Trilobatin, a natural compound, has been found to exhibit anti-diabetic properties in high-fat diet (HFD) and streptozotocin (STZ) induced type 2 diabetic mice. But up to now no research has been reported on the effect of trilobatin on insulin resistance in peripheral tissues. Herein, we determined the effects of trilobatin on insulin resistance in palmitate-treated C2C12 myotubes and ob/ob mice.Methods: 8-10 weeks of male ob/ob mice and same background C57BL/6 mice were used to evaluate the role of trilobatin on insulin resistance; Protein expression and phosphorylation were measured by western blot; Glucose uptake was determined a fluorescent test.Results: treatment with trilobatin prevented palmitate-induced insulin resistance by enhancing glucose uptake and the phosphorylation of IRS1 and AKT, recovered the translocation of GLUT4 from cytoplasm to membrane, but preincubation with LY294002, an inhibitor of PI3K, blocked the effects of trilobatin on glucose uptake and the distribution of GLUT4 in C2C12 myotubes. Furthermore, administration with trilobatin for 4 weeks significantly improved insulin resistance by decreasing fasting blood glucose and insulin in serum, enhancing the phosphorylation of IRS1 and AKT, and recovering the expression and translocation of GLUT4 in ob/ob mice.Conclusions: IRS-AKT-GLUT4 signaling pathway might be involved in trilobatin ameliorating insulin resistance in skeletal muscle of obese animal models.


2008 ◽  
Vol 22 (S2) ◽  
pp. 683-683 ◽  
Author(s):  
Jin Taek Hwang ◽  
MyoungSu Lee ◽  
MyungSunny Kim ◽  
Dae Young Kwon

Nutrients ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 765 ◽  
Author(s):  
Sun-Young Yoon ◽  
Seoung Rak Lee ◽  
Ji Young Hwang ◽  
René Benndorf ◽  
Christine Beemelmanns ◽  
...  

Type 2 diabetes is a complex, heterogeneous, and polygenic disease. Currently, available drugs for treating type 2 diabetes predominantly include sulfonylureas, α-glucosidase inhibitors, and biguanides. However, long-term treatment with these therapeutic drugs is often accompanied by undesirable side effects, which have driven interest in the development of more effective and safer antidiabetic agents. To address the urgent need for new chemical solutions, we focused on the analysis of structurally novel and/or biologically new metabolites produced by insect-associated microbes as they have recently been recognized as a rich source of natural products. Comparative LC/MS-based analysis of Actinomadura sp. RB99, isolated from a fungus-growing termite, led to the identification of the type II polyketide synthase-derived fridamycin A. The structure of fridamycin A was confirmed by 1H NMR data and LC/MS analysis. The natural microbial product, fridamycin A, was examined for its antidiabetic properties in 3T3-L1 adipocytes, which demonstrated that fridamycin A induced glucose uptake in 3T3-L1 cells by activating the AMP-activated protein kinase (AMPK) signaling pathway but did not affect adipocyte differentiation, suggesting that the glucose uptake took place through activation of the AMPK signaling pathway without inducing adipogenesis. Our results suggest that fridamycin A has potential to induce fewer side effects such as weight gain compared to rosiglitazone, a commonly used antidiabetic drug, and that fridamycin A could be a novel potential therapeutic candidate for the management of type 2 diabetes.


2001 ◽  
Vol 280 (4) ◽  
pp. E554-E561 ◽  
Author(s):  
Shujia J. Pan ◽  
Joe Hancock ◽  
Zhenping Ding ◽  
Donovan Fogt ◽  
Mancheong Lee ◽  
...  

The present study was conducted to determine the effect of chronic administration of the long-acting β2-adrenergic agonist clenbuterol on rats that are genetically prone to insulin resistance and impaired glucose tolerance. Obese Zucker rats ( fa/fa) were given 1 mg/kg of clenbuterol by oral intubation daily for 5 wk. Controls received an equivalent volume of water according to the same schedule. At the end of the treatment, rats were catheterized for euglycemic-hyperinsulinemic (15 mU insulin · kg−1 · min−1) clamping. Clenbuterol did not change body weight compared with the control group but caused a redistribution of body weight: leg muscle weights increased, and abdominal fat weight decreased. The glucose infusion rate needed to maintain euglycemia and the rate of glucose disappearance were greater in the clenbuterol-treated rats. Furthermore, plasma insulin levels were decreased, and the rate of glucose uptake into hindlimb muscles and abdominal fat was increased in the clenbuterol-treated rats. This increased rate of glucose uptake was accompanied by a parallel increase in the rate of glycogen synthesis. The increase in muscle glucose uptake could not be ascribed to an increase in the glucose transport protein GLUT-4 in clenbuterol-treated rats. We conclude that chronic clenbuterol treatment reduces the insulin resistance of the obese Zucker rat by increasing insulin-stimulated muscle and adipose tissue glucose uptake. The improvements noted may be related to the repartitioning of body weight between tissues.


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