Exposure to Perfluoro-Octanoic Acid Associated With Upstream Uncoupling of the Insulin Signaling in Human Hepatocyte Cell Line

Perfluoro–alkyl substances (PFAS) are chemical pollutants with prevalent stability and environmental persistence. Exposure to PFAS, particularly perfluoro-octanoic acid (PFOA), has been associated with increased diabetes-related cardiovascular mortality in subjects residing areas of high environmental contamination, however the exact pathogenic mechanism remains elusive. Here we used HepG2 cells, an in vitro model of human hepatocyte, to investigate the possible role of PFOA exposure in the alteration of hepatic glucose metabolism. HepG2 cells were exposed for 24 hours to PFOA at increasing concentration from 0 to 1000 ng/mL and then stimulated with 100 nm Insulin (Ins). The consequent effect on glycogen synthesis, glucose uptake and Glut-4 glucose transporter translocation was then evaluated by, respectively, Periodic Acid Schiff (PAS) staining, 2-deoxyglucose (2-DG) uptake assay and immunofluorescence. Exposure to PFOA was associated with reduced glycogen synthesis and glucose uptake, at concentration equal or greater than, respectively, 0,1 ng/mL and 10 ng/mL, with parallel impaired membrane translocation of Glut-4 upon Ins stimulation. Western blot analysis showed early uncoupling of Insulin Receptor (InsR) activation from the downstream Akt and GSK3 phosphorylation. Computational docking analysis disclosed the possible stabilizing effect of PFOA on the complex between InsR and GM3 ganglioside, previously shown to be associated with the low grade chronic inflammation-related insulin resistance. Consistently, long term treatment with glucosyl-ceramide synthase inhibitor PDMP was able to largely restore glycogen synthesis, glucose uptake and Glut-4 translocation upon Ins stimulation in HepG2 exposed to PFOA. Our data support a novel pathogenic mechanism linking exposure to PFOA to derangement of hepatocyte cell metabolism.

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Bombyxin II Regulates Glucose Absorption and Glycogen Synthesis through the PI3K Signaling Pathway in HepG2 Cells

BioMed Research International ◽

10.1155/2021/6639232 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Hongliang Yang ◽

Hongxia Li ◽

Yang Song ◽

Yujie Sui ◽

Zhenwu Du ◽

...

Keyword(s):

Glucose Uptake ◽

Bombyx Mori ◽

Signaling Pathway ◽

Hepg2 Cells ◽

Mammalian Cells ◽

Periodic Acid ◽

Glycogen Synthesis ◽

Glucose Absorption ◽

Pi3k Signaling ◽

Pi3k Signaling Pathway

Bombyxin, as an insulin-like insect hormone, was discovered in the silkmoth Bombyx mori. It can regulate the metabolism of trehalose and glycogen in Bombyx mori, but whether it has glucose absorption and glycogen synthesis effect on mammalian cells was not clear. BombyxinII (BbxII) and mutant BbxII (mBbxII) genes were cloned into pcDNA3.1(+) vector, respectively; then, gene vectors were transfected into 293FT cells using Lipofectamine 2000. Levels of mRNA and protein expression of BbxII and mBbxII were detected by PCR and Western blot in 293FT cells, respectively. Glucose consumption and glycogenesis were determined by glucose oxidase-peroxidase (GOD-POD) and periodic acid-Schiff (PAS) staining in HepG2 cells; the PI3K signaling pathway was inhibited with wortmannin S1952 in HepG2 cells. Result showed that BbxII and mBbxII genes were being successfully expressed in 293FT cells, respectively. The expression protein of BbxII gene is 10kd pre-bombyxinII, and yet, the expression protein of mBbxII gene is 4kd mature bombyxinII. Only the 4kd bombyxinII showed increased glucose uptake and glycogenesis in HepG2 cells, and the ability of increasing glucose uptake was equal to the human insulin (10 nM). PI3K-wortmannin S1952 inhibitor can decrease the glycogen synthesis induced by bombyxin II protein in HepG2 cells. In conclusion, mature bombyxin II may adjust glucose absorption and glycogen synthesis in HepG2 cells through the PI3K signaling pathway.

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Diverse effects of Glut 4 ablation on glucose uptake and glycogen synthesis in red and white skeletal muscle.

Journal of Clinical Investigation ◽

10.1172/jci118833 ◽

1996 ◽

Vol 98 (3) ◽

pp. 629-634 ◽

Cited By ~ 53

Author(s):

A E Stenbit ◽

R Burcelin ◽

E B Katz ◽

T S Tsao ◽

N Gautier ◽

...

Keyword(s):

Skeletal Muscle ◽

Glucose Uptake ◽

Glycogen Synthesis ◽

Glut 4

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Palbinone and triterpenes from Moutan Cortex (Paeonia suffruticosa, Paeoniaceae) stimulate glucose uptake and glycogen synthesis via activation of AMPK in insulin-resistant human HepG2 Cells

Bioorganic & Medicinal Chemistry Letters ◽

10.1016/j.bmcl.2009.08.048 ◽

2009 ◽

Vol 19 (19) ◽

pp. 5556-5559 ◽

Cited By ~ 38

Author(s):

Do Thi Ha ◽

Dao Trong Tuan ◽

Nguyen Bich Thu ◽

Nguyen Xuan Nhiem ◽

Tran Minh Ngoc ◽

...

Keyword(s):

Glucose Uptake ◽

Hepg2 Cells ◽

Glycogen Synthesis ◽

Paeonia Suffruticosa ◽

Insulin Resistant ◽

Moutan Cortex

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Hydrogen Sulfide Impairs Glucose Utilization and Increases Gluconeogenesis in Hepatocytes

Endocrinology ◽

10.1210/en.2012-1658 ◽

2013 ◽

Vol 154 (1) ◽

pp. 114-126 ◽

Cited By ~ 44

Author(s):

Ling Zhang ◽

Guangdong Yang ◽

Ashley Untereiner ◽

Youngjun Ju ◽

Lingyun Wu ◽

...

Keyword(s):

Hydrogen Sulfide ◽

Protein Kinase ◽

Glucose Uptake ◽

Hepg2 Cells ◽

Phosphoenolpyruvate Carboxykinase ◽

Glucose Utilization ◽

Glycogen Content ◽

Glycogen Synthesis ◽

Primary Mouse ◽

Amp Activated Protein Kinase

Mounting evidence has established hydrogen sulfide (H2S) as an important gasotransmitter with multifaceted physiological functions. The aim of the present study was to investigate the role of H2S on glucose utilization, glycogen synthesis, as well as gluconeogenesis in both HepG2 cells and primary mouse hepatocytes. Incubation with NaHS (a H2S donor) impaired glucose uptake and glycogen storage in HepG2 cells via decreasing glucokinase activity. Adenovirus-mediated cystathionine γ-lyase (CSE) overexpression increased endogenous H2S production and lowered glycogen content in HepG2 cells. Glycogen content was significantly higher in liver tissues from CSE knockout (KO) mice compared to that from wild type (WT) mice in fed condition. Glucose consumption was less in primarily cultured hepatocytes isolated from WT mice than those from CSE KO mice, but more glucose was produced by hepatocytes via gluconeogenesis and glycogenolysis pathways in WT mice than in CSE KO mice. NaHS treatment reduced the phosphorylation of AMP-activated protein kinase, whereas stimulation of AMP-activated protein kinase by 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside reversed H2S-impaired glucose uptake. H2S-increased glucose production was likely through increased phosphoenolpyruvate carboxykinase activity. In addition, insulin at the physiological range inhibited CSE expression, and H2S decreased insulin-stimulated phosphorylation of Akt in HepG2 cells. CSE expression was increased, however, in insulin-resistant state induced by exposing cells to high levels of insulin (500 nm) and glucose (33 mm) for 24 h. Taken together, these data suggest that the interaction of H2S and insulin in liver plays a pivotal role in regulating insulin sensitivity and glucose metabolism.

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Selected compounds derived from Moutan Cortex stimulated glucose uptake and glycogen synthesis via AMPK activation in human HepG2 cells

Journal of Ethnopharmacology ◽

10.1016/j.jep.2010.07.010 ◽

2010 ◽

Vol 131 (2) ◽

pp. 417-424 ◽

Cited By ~ 34

Author(s):

Do Thi Ha ◽

Trinh Nam Trung ◽

Tran Thi Hien ◽

Trong Tuan Dao ◽

Namhui Yim ◽

...

Keyword(s):

Glucose Uptake ◽

Hepg2 Cells ◽

Glycogen Synthesis ◽

Ampk Activation ◽

Moutan Cortex

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ChemInform Abstract: Palbinone and Triterpenes from Moutan Cortex (Paeonia suffruticosa, Paeoniaceae) Stimulate Glucose Uptake and Glycogen Synthesis via Activation of AMPK in Insulin-Resistant Human HepG2 Cells.

ChemInform ◽

10.1002/chin.201007181 ◽

2010 ◽

Vol 41 (7) ◽

Author(s):

Do Thi Ha ◽

Dao Trong Tuan ◽

Nguyen Bich Thu ◽

Nguyen Xuan Nhiem ◽

Tran Minh Ngoc ◽

...

Keyword(s):

Glucose Uptake ◽

Hepg2 Cells ◽

Glycogen Synthesis ◽

Paeonia Suffruticosa ◽

Insulin Resistant ◽

Moutan Cortex

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Effects of high-fat diet and exercise training on intracellular glucose metabolism in rats

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2000.278.6.e977 ◽

2000 ◽

Vol 278 (6) ◽

pp. E977-E984 ◽

Cited By ~ 48

Author(s):

Chul-Hee Kim ◽

Jang H. Youn ◽

Joong-Yeol Park ◽

Sung K. Hong ◽

Kyong S. Park ◽

...

Keyword(s):

Glucose Metabolism ◽

Exercise Training ◽

Glucose Uptake ◽

Protein Content ◽

High Fat Diet ◽

Glycogen Synthesis ◽

Whole Body ◽

High Fat ◽

Glut 4 ◽

Intracellular Glucose

We examined the effects of high-fat diet (HFD) and exercise training on insulin-stimulated whole body glucose fluxes and several key steps of glucose metabolism in skeletal muscle. Rats were maintained for 3 wk on either low-fat (LFD) or high-fat diet with or without exercise training (swimming for 3 h per day). After the 3-wk diet/exercise treatments, animals underwent hyperinsulinemic euglycemic clamp experiments for measurements of insulin-stimulated whole body glucose fluxes. In addition, muscle samples were taken at the end of the clamps for measurements of glucose 6-phosphate (G-6- P) and GLUT-4 protein contents, hexokinase, and glycogen synthase (GS) activities. Insulin-stimulated glucose uptake was decreased by HFD and increased by exercise training ( P < 0.01 for both). The opposite effects of HFD and exercise training on insulin-stimulated glucose uptake were associated with similar increases in muscle G-6- P levels ( P < 0.05 for both). However, the increase in G-6- Plevel was accompanied by decreased GS activity without changes in GLUT-4 protein content and hexokinase activities in the HFD group. In contrast, the increase in G-6- P level in the exercise-trained group was accompanied by increased GLUT-4 protein content and hexokinase II (cytosolic) and GS activities. These results suggest that HFD and exercise training affect insulin sensitivity by acting predominantly on different steps of intracellular glucose metabolism. High-fat feeding appears to induce insulin resistance by affecting predominantly steps distal to G-6- P (e.g., glycolysis and glycogen synthesis). Exercise training affected multiple steps of glucose metabolism both proximal and distal to G-6- P. However, increased muscle G-6- P levels in the face of increased glucose metabolic fluxes suggest that the effect of exercise training is quantitatively more prominent on the steps proximal to G-6- P(i.e., glucose transport and phosphorylation).

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Autocrine role of interleukin-13 on skeletal muscle glucose metabolism in type 2 diabetic patients involves microRNA let-7

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00236.2013 ◽

2013 ◽

Vol 305 (11) ◽

pp. E1359-E1366 ◽

Cited By ~ 66

Author(s):

Lake Q. Jiang ◽

Niclas Franck ◽

Brendan Egan ◽

Rasmus J. O. Sjögren ◽

Mutsumi Katayama ◽

...

Keyword(s):

Skeletal Muscle ◽

Glucose Uptake ◽

Glycogen Synthesis ◽

Neutralizing Antibody ◽

Diabetic Patients ◽

Low Grade ◽

Type 2 Diabetic Patients ◽

Increase Glucose Uptake ◽

Cultured Myotubes

Low-grade inflammation associated with type 2 diabetes (T2DM) is postulated to exacerbate insulin resistance. We report that serum levels, as well as IL-13 secreted from cultured skeletal muscle, are reduced in T2DM vs. normal glucose-tolerant (NGT) subjects. IL-13 exposure increases skeletal muscle glucose uptake, oxidation, and glycogen synthesis via an Akt-dependent mechanism. Expression of microRNA let-7a and let-7d, which are direct translational repressors of the IL-13 gene, was increased in skeletal muscle from T2DM patients. Overexpression of let-7a and let-7d in cultured myotubes reduced IL-13 secretion. Furthermore, basal glycogen synthesis was reduced in cultured myotubes exposed to an IL-13-neutralizing antibody. Thus, IL-13 is synthesized and released by skeletal muscle through a mechanism involving let-7, and this effect is attenuated in skeletal muscle from insulin-resistant T2DM patients. In conclusion, IL-13 plays an autocrine role in skeletal muscle to increase glucose uptake and metabolism, suggesting a role in glucose homeostasis in metabolic disease.

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