scholarly journals Visfatin Induces Inflammation and Insulin Resistance via the NF-κB and STAT3 Signaling Pathways in Hepatocytes

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Yu Jung Heo ◽  
Sung-E Choi ◽  
Ja Young Jeon ◽  
Seung Jin Han ◽  
Dae Jung Kim ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Signaling Pathways ◽  
Western Blotting ◽  
Insulin Signaling ◽  
Proinflammatory Cytokine ◽  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Immunocytochemical Staining ◽  
Mrna Levels ◽  
Rt Pcr

Background. It has been suggested that visfatin, which is an adipocytokine, exhibits proinflammatory properties and is associated with insulin resistance. Insulin resistance and inflammation are the principal pathogeneses of nonalcoholic fatty liver disease (NAFLD), but the relationship, if any, between visfatin and NAFLD remains unclear. Here, we evaluated the effects of visfatin on hepatic inflammation and insulin resistance in HepG2 cells and examined the molecular mechanisms involved. Methods. After treatment with visfatin, the inflammatory cytokines IL-6, TNF-α, and IL-1β were assessed by real-time polymerase chain reaction (RT-PCR) and immunocytochemical staining in HepG2 cells. To investigate the effects of visfatin on insulin resistance, we evaluated insulin-signaling pathways, such as IR, IRS-1, GSK, and AKT using immunoblotting. We assessed the intracellular signaling molecules including STAT3, NF-κB, IKK, p38, JNK, and ERK by western blotting. We treated HepG2 cells with both visfatin and either AG490 (a JAK2 inhibitor) or Bay 7082 (an NF-κB inhibitor); we examined proinflammatory cytokine mRNA levels using RT-PCR and insulin signaling using western blotting. Results. In HepG2 cells, visfatin significantly increased the levels of proinflammatory cytokines, reduced the levels of proteins (e.g., phospho-IR, phospho-IRS-1 (Tyr612), phospho-AKT, and phospho-GSK-3α/β) involved in insulin signaling, and increased IRS-1 S307 phosphorylation compared to controls. Interestingly, visfatin increased the activities of the JAK2/STAT3 and IKK/NF-κB signaling pathways but not those of the JNK, p38, and ERK pathways. Visfatin-induced inflammation and insulin resistance were regulated by JAK2/STAT3 and IKK/NF-κB signaling; together with AG490 or Bay 7082, visfatin significantly reduced mRNA levels of IL-6, TNF-α and IL-1β and rescued insulin signaling. Conclusion. Visfatin induced proinflammatory cytokine production and inhibited insulin signaling via the STAT3 and NF-κB pathways in HepG2 cells.

Negative Correlation Between Serum Levels of Homocysteine and Apolipoprotein M

2019 ◽  
Vol 19 (2) ◽  
pp. 120-126
Author(s):  
J. Wei ◽  
Y. Yu ◽  
Y. Feng ◽  
J. Zhang ◽  
Q. Jiang ◽  
...  
Keyword(s):  
Negative Correlation ◽  
Hepg2 Cells ◽  
Serum Levels ◽  
Significant Negative Correlation ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Apolipoprotein M ◽  
Protein Mass ◽  
Protein Levels ◽  
Phosphoinositide 3 Kinase

Background: Homocysteine (Hcy) has been suggested as an independent risk factor for atherosclerosis. Apolipoprotein M (apoM) is a constituent of the HDL particles. The goal of this study was to examine the serum levels of homocysteine and apoM and to determine whether homocysteine influences apoM synthesis. Methods: Serum levels of apoM and Hcy in 17 hyperhomocysteinemia (HHcy) patients and 19 controls were measured and their correlations were analyzed. Different concentrations of homocysteine (Hcy) and LY294002, a specific phosphoinositide 3- kinase (PI3K) inhibitor, were used to treat HepG2 cells. The mRNA levels were determined by RT-PCR and the apoM protein mass was measured by western blot. Results: We found that decreased serum apoM levels corresponded with serum HDL levels in HHcy patients, while the serum apoM levels showed a statistically significant negative correlation with the serum Hcy levels. Moreover, apoM mRNA and protein levels were significantly decreased after the administration of Hcy in HepG2 cells, and this effect could be abolished by addition of LY294002. Conclusions: resent study demonstrates that Hcy downregulates the expression of apoM by mechanisms involving the PI3K signal pathway.

Inhibition of Migration and Invasion of Hepatocarcinoma HepG2 Cells by Dietary Saponins via Targeting HIF-1α

2018 ◽  
Vol 18 (7) ◽  
pp. 1025-1031
Author(s):  
Cheng Luo ◽  
Di Wu ◽  
Meiling Chen ◽  
Wenhua Miao ◽  
Changfeng Xue ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Confocal Microscopy ◽  
Protein Expression ◽  
Mtt Assay ◽  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Migration And Invasion ◽  
Rt Pcr ◽  
Gene And Protein Expression ◽  
Simulated Hypoxia

Background: Different saponins from herbs have been used as tonic or functional foods, and for treatment of various diseases including cancers. Although clinical data has supported the function of these saponins, their underlying molecular mechanisms have not been well defined. Methods: With the simulated hypoxia created by 8 hours of Cu++ exposure and following 24 hour incubation with different concentration of saponins in HepG2 cells for MTT assay, migration and invasion assays, and for RT-PCR, and with each group of cells for immunofluorescence observation by confocal microscopy. Results： ZC-4 had the highest rate of inhibition of cell proliferation by MTT assay, and the highest inhibition of migration rate by in vitro scratch assay, while ZC-3 had the highest inhibition of invasion ratio by transwell assay. Under the same simulated hypoxia, the molecular mechanism of saponin function was conducted by measuring the gene expression of Hypoxia Inducible Factor (HIF)-1α through RT-PCR, in which ZC-3 showed a potent inhibition of gene HIF-1α. For the protein expression by immunofluorescence staining with confocal microscopy, HIF-1α was also inhibited by saponins, with the most potent one being ZC-4 after eight hours’ relatively hypoxia incubation. Conclusion: Saponins ZC-4 and ZC-3 have the potential to reduce HepG2 cell proliferation, migration and invasion caused by hypoxia through effectively inhibiting the gene and protein expression of HIF-1α directly and as antioxidant indirectly

scholarly journals Insulin Resistance and Diabetes Mellitus in Alzheimer’s Disease

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1236
Author(s):  
Jesús Burillo ◽  
Patricia Marqués ◽  
Beatriz Jiménez ◽  
Carlos González-Blanco ◽  
Manuel Benito ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Alzheimer’S Disease ◽  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Alzheimer's Disease ◽  
Type 2 Diabetes Mellitus ◽  
Insulin Signaling ◽  
Molecular Mechanisms ◽  
Progressive Disease

Type 2 diabetes mellitus is a progressive disease that is characterized by the appearance of insulin resistance. The term insulin resistance is very wide and could affect different proteins involved in insulin signaling, as well as other mechanisms. In this review, we have analyzed the main molecular mechanisms that could be involved in the connection between type 2 diabetes and neurodegeneration, in general, and more specifically with the appearance of Alzheimer’s disease. We have studied, in more detail, the different processes involved, such as inflammation, endoplasmic reticulum stress, autophagy, and mitochondrial dysfunction.

Abstract 628: Hepatic Insulin Signaling Regulates ApoA-I Gene Expression Through the Type I Deiodinase.

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Jing Liu ◽  
Antonio Hernandez-Ono ◽  
Valerie Galton ◽  
Henry Ginsberg
Keyword(s):  
Insulin Signaling ◽  
Knockout Mice ◽  
Hepg2 Cells ◽  
Density Lipoprotein ◽  
Type I ◽  
Mrna Levels ◽  
Reverse T3 ◽  
Hepatic Insulin Signaling ◽  
Low Levels

People with low levels of high density lipoprotein cholesterol (HDLC) and apolipoprotein A-I (ApoA-I) have a higher risk of cardiovascular disease. Low levels of HDLC are common in individuals who are insulin resistant (IR), e.g., with metabolic syndrome and type 2 diabetes mellitus (T2DM). Despite the high prevalence of these two disorders, very little work has been reported regarding the molecular pathways linking insulin signaling or action and the levels of either HDLC or ApoA-1. We reported previously that liver specific insulin receptor (InsR) knockout mice (LIRKO) have markedly reduced plasma HDLC levels that increase after restoration of hepatic Akt signaling. In the present study, we created acute LIRKO mice by injecting an albumin-Cre adenovirus (Ad) into InsR floxed mice and observed marked reductions in HDLC, the expression of ApoA-I, and the expression of the gene coding Type1 iodothyronine deiodinase1, a selenoenzyme expressed highly in the liver that converts thyroxine to 3,5,3’-triiodothyronine (T3) or reverse T3. Deiodinase 1 knockout mice also had significantly reduced hepatic ApoA-I mRNA levels. Overexpression of Dio1 in LIRKO restored HDLC and significantly increased the expression of ApoA-I mRNA. In vitro studies showed that the expression of ApoA-I was significantly reduced after knockdown of either InsR or Dio1 expression in HepG2 cells. Moreover, overexpression of Dio1 restored ApoA-I promoter activity that had been decreased by knockdown of InsR. Deletion analysis of ApoAI promoter regions showed that insulin signaling regulated ApoA-I expression by acting on a region which does not contain any thyroid response elements. Pulse-chase experiments in HepG2 cells showed that deficiency of insulin signaling resulted in decreased synthesis and secretion of ApoAI. Our results indicates that defective hepatic insulin signaling results in reduced expression of Dio1 which, in turn, leads to reduced expression of ApoA-I and decreased synthesis and secretion of ApoA-I from hepatocytes. We believe our studies have defined a novel pathway from insulin signaling to ApoA-I synthesis that may lead to new approaches for increasing HDL levels in people with defective insulin signaling.

scholarly journals Anticancer Effects of Emodin on HepG2 Cell: Evidence from Bioinformatic Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Rui-sheng Zhou ◽  
Xiong-Wen Wang ◽  
Qin-feng Sun ◽  
Zeng Jie Ye ◽  
Jian-wei Liu ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Mapk Signaling ◽  
Ion Concentration ◽  
Receptor Interaction ◽  
Pathway Enrichment Analysis ◽  
Mrna Levels ◽  
Hub Genes ◽  
Positive Regulation

Hepatocellular carcinoma (HCC) is a primary cause of cancer-related death in the world. Despite the fact that there are many methods to treat HCC, the 5-year survival rate of HCC is still at a low level. Emodin can inhibit the growth of HCC cells invitroand invivo. However, the gene regulation of emodin in HCC has not been well studied. In our research, RNA sequencing technology was used to identify the differentially expressed genes (DEGs) in HepG2 cells induced by emodin. A total of 859 DEGs were identified, including 712 downregulated genes and 147 upregulated genes in HepG2 cells treated with emodin. We used DAVID for function and pathway enrichment analysis. The protein-protein interaction (PPI) network was constructed using STRING, and Cytoscape was used for module analysis. The enriched functions and pathways of the DEGs include positive regulation of apoptotic process, structural molecule activity and lipopolysaccharide binding, protein digestion and absorption, ECM-receptor interaction, complement and coagulation cascades, and MAPK signaling pathway. 25 hub genes were identified and pathway analysis revealed that these genes were mainly enriched in neuropeptide signaling pathway, inflammatory response, and positive regulation of cytosolic calcium ion concentration. Survival analysis showed that LPAR6, C5, SSTR5, GPR68, and P2RY4 may be involved in the molecular mechanisms of emodin therapy for HCC. A quantitative real-time PCR (qRT-PCR) assay showed that the mRNA levels of LPAR6, C5, SSTR5, GPR68, and P2RY4 were significantly decreased in HepG2 cells treated with emodin. In conclusion, the identified DEGs and hub genes in the present study provide new clues for further researches on the molecular mechanisms of emodin.

scholarly journals Wu-Mei-Wan Reduces Insulin Resistance via Inhibition of NLRP3 Inflammasome Activation in HepG2 Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Xueping Yang ◽  
Lingli Li ◽  
Ke Fang ◽  
Ruolan Dong ◽  
Jingbin Li ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Receptor ◽  
Insulin Signaling ◽  
Nlrp3 Inflammasome ◽  
Hepg2 Cells ◽  
Glucose Transporter ◽  
Interleukin 1 ◽  
Serine Phosphorylation ◽  
Inflammasome Activation ◽  
Glucose Consumption Rate

Wu-Mei-Wan (WMW) is a Chinese herbal formula used to treat type 2 diabetes. In this study, we aimed to explore the effects and mechanisms of WMW on insulin resistance in HepG2 cells. HepG2 cells were pretreated with palmitate (0.25 mM) to impair the insulin signaling pathway. Then, they were treated with different doses of WMW-containing medicated serum and stimulated with 100 nM insulin. Results showed that palmitate could reduce the glucose consumption rate in HepG2 cells and impair insulin signaling related to phosphorylation of insulin receptor (IR) and insulin receptor substrate-1 (IRS-1), thereby regulating the downstream signaling pathways. However, medicated serum of WMW restored impaired insulin signaling, upregulated the expression of phospho-IR (pIR), phosphatidylinositol 3-kinase p85 subunit, phosphoprotein kinase B, and glucose transporter 4, and decreased IRS serine phosphorylation. In addition, it decreased the expression of interleukin-1β and tumor necrosis factor-α, which are the key proinflammatory cytokines involved in insulin resistance; besides, it reduced the expression of NLRP3 inflammasome. These results suggested that WMW could alleviate palmitate-induced insulin resistance in HepG2 cells via inhibition of NLRP3 inflammasome and reduction of proinflammatory cytokine production.

Cafeteria diet-induced insulin resistance is not associated with decreased insulin signaling or AMPK activity and is alleviated by physical training in rats

2010 ◽  
Vol 299 (2) ◽  
pp. E215-E224 ◽  
Author(s):  
Nina Brandt ◽  
Katrien De Bock ◽  
Erik A. Richter ◽  
Peter Hespel
Keyword(s):  
Insulin Resistance ◽  
Exercise Training ◽  
Energy Intake ◽  
Insulin Signaling ◽  
Molecular Mechanisms ◽  
Cafeteria Diet ◽  
Low Fat ◽  
Low Fat Diet ◽  
Male Wistar Rats ◽  
Syntaxin 4

Excess energy intake via a palatable low-fat diet (cafeteria diet) is known to induce obesity and glucose intolerance in rats. However, the molecular mechanisms behind this adaptation are not known, and it is also not known whether exercise training can reverse it. Male Wistar rats were assigned to 12-wk intervention groups: chow-fed controls (CON), cafeteria diet (CAF), and cafeteria diet plus swimming exercise during the last 4 wk (CAFTR). CAF feeding led to increased body weight (16%, P < 0.01) and increased plasma glucose ( P < 0.05) and insulin levels ( P < 0.01) during an IVGTT, which was counteracted by training. In the perfused hindlimb, insulin-stimulated glucose transport in red gastrocnemius muscle was completely abolished in CAF and rescued by exercise training. Apart from a tendency toward an ∼20% reduction in both basal and insulin-stimulated Akt Ser473 phosphorylation ( P = 0.051) in the CAF group, there were no differences in insulin signaling (IR Tyr1150/1151, PI 3-kinase activity, Akt Thr308, TBC1D4 Thr642, GSK3-α/β Ser21/9) or changes in AMPKα1 or -α2, GLUT4, Munc18c, or syntaxin 4 protein expression or in phosphorylation of AMPK Thr172 among the groups. In conclusion, surplus energy intake of a palatable but low-fat cafeteria diet resulted in obesity and insulin resistance that was rescued by exercise training. Interestingly, insulin resistance was not accompanied by major defects in the insulin-signaling cascade or in altered AMPK expression or phosphorylation. Thus, compared with previous studies of high-fat feeding, where insulin signaling is significantly impaired, the mechanism by which CAF diet induces insulin resistance seems different.

scholarly journals Role of Neu-p11/luzindole in the regulation of insulin signaling pathways and insulin resistance

2016 ◽  
Vol 48 (5) ◽  
pp. 485-486
Author(s):  
Xiuping Li ◽  
Shichang Cai ◽  
Weidong Yin ◽  
Xiaobo Hu ◽  
Sujun Zhang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Signaling Pathways ◽  
Insulin Signaling

scholarly journals Hydrangea serrata (Thunb.) Ser. Extract Attenuate UVB-Induced Photoaging through MAPK/AP-1 Inactivation in Human Skin Fibroblasts and Hairless Mice

Nutrients ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 533 ◽  
Author(s):  
Hee-Soo Han ◽  
Ji-Sun Shin ◽  
Da-Bin Myung ◽  
Hye Ahn ◽  
Sun Lee ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Mapk Signaling ◽  
Collagen Degradation ◽  
Hot Water ◽  
Mrna Levels ◽  
Skin Damage ◽  
Hairless Mice ◽  
Skin Photoaging ◽  
Mapk Signaling Pathways

Skin photoaging is mainly caused by exposure to ultraviolet (UV) light, which increases expressions of matrix metalloproteinases (MMPs) and destroys collagen fibers, consequently inducing wrinkle formation. Nutritional factors have received scientific attention for use as agents for normal skin functions. The aim of this study was to investigate the effect of hot water extracts from the leaves of Hydrangea serrata (Thunb.) Ser. (WHS) against ultraviolet B (UVB)-induced skin photoaging and to elucidate the underlying molecular mechanisms in human foreskin fibroblasts (Hs68) and HR-1 hairless mice. WHS recovered UVB-reduced cell viability and ameliorated oxidative stress by inhibiting intracellular reactive oxygen species (ROS) generation in Hs68 cells. WHS rescued UVB-induced collagen degradation by suppressing MMP expression, and reduced the mRNA levels of inflammatory cytokines. These anti-photoaging activities of WHS were associated with inhibition of the activator protein 1 (AP-1), signal transduction and activation of transcription 1 (STAT1), and mitogen-activated protein kinase (MAPK) signaling pathways. Oral administration of WHS effectively alleviated dorsal skin from wrinkle formation, epidermal thickening, collagen degradation, and skin dehydration in HR-1 hairless mice exposed to UVB. Notably, WHS suppressed UVB activation of the AP-1 and MAPK signaling pathways in dorsal mouse skin tissues. Taken together, our data indicate that WHS prevents UVB-induced skin damage due to collagen degradation and MMP activation via inactivation of MAPK/AP-1 signaling pathway.

scholarly journals Glycyrrhetinic Acid Improves Insulin-Response Pathway by Regulating the Balance between the Ras/MAPK and PI3K/Akt Pathways

Nutrients ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 604 ◽  
Author(s):  
Yuan Zhang ◽  
Shengnan Yang ◽  
Man Zhang ◽  
Zhihua Wang ◽  
Xin He ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Protein Kinase ◽  
Insulin Signaling ◽  
Hepg2 Cells ◽  
Mapk Pathway ◽  
Insulin Response ◽  
Glycyrrhetinic Acid ◽  
Intracellular Enzyme ◽  
Target Proteins ◽  
Iκb Kinase

Glycyrrhetinic acid (GA), a bioactive component in the human diet, has been reported to improve hyperglycemia, dyslipidemia, insulin resistance and obesity in rats with metabolic syndrome. However, GA-specific target proteins and the mechanisms involved in the downstream signaling and cross-talk to improve insulin sensitivity have not been fully elucidated. In this study, the potential targets of GA were identified by chemical proteomics strategies using serial GA probes for target fishing and cell molecular imaging. Intracellular enzyme activity evaluation and insulin resistance models were used for validating the function of the target proteins on the downstream insulin signaling pathways. Collectively, our data demonstrate that GA improved the insulin-responsive pathway and glucose consumption levels via multiple diabetogenic factors that activated the insulin signaling pathway in HepG2 cells. GA improved Glucose transporter 4(GLUT4) expression by targeting the Ras protein to regulate the mitogen-activated protein kinase (MAPK) pathway. GA exhibited a strong inhibitory effect on IRS1ser307 phosphorylation in cells treated with the Protein kinase C (PKC) activator Phorbol 12-myristate 13-acetate (PMA.) Consistently, IRS1ser307 phosphorylation was also inhibited by GA in Free fatty acid (FFA)-treated HepG2 cells. GA also inhibited the PMA-induced phosphorylation of IκB kinase α/β (IKKα/β), c-Jun N-terminal kinase (JNK) and p38 proteins (P38), suggesting that IKKα/β, JNK and P38 activation is dependent on PKC activity.

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