scholarly journals Resveratrol, an activator of SIRT1, improves ER stress by increasing clusterin expression in HepG2 cells

2019 ◽  
Vol 24 (4) ◽  
pp. 825-833 ◽  
Author(s):  
Jinmi Lee ◽  
Seok-Woo Hong ◽  
Hyemi Kwon ◽  
Se Eun Park ◽  
Eun-Jung Rhee ◽  
...  
Keyword(s):  
Er Stress ◽  
Hepg2 Cells ◽  
Clusterin Expression

scholarly journals Aqueous Extract of Pepino Leaves Ameliorates Palmitic Acid-Induced Hepatocellular Lipotoxicity via Inhibition of Endoplasmic Reticulum Stress and Apoptosis

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 903
Author(s):  
Jen-Ying Hsu ◽  
Hui-Hsuan Lin ◽  
Charng-Cherng Chyau ◽  
Zhi-Hong Wang ◽  
Jing-Hsien Chen
Keyword(s):  
Fatty Acid ◽  
Palmitic Acid ◽  
Er Stress ◽  
Lipid Accumulation ◽  
Hepg2 Cells ◽  
Target Genes ◽  
Liver Lipid ◽  
Antioxidant Response ◽  
Long Chain Fatty Acid ◽  
Nrf2 Expression

Saturated fatty acid is one of the important nutrients, but contributes to lipotoxicity in the liver, causing hepatic steatosis. Aqueous pepino leaf extract (AEPL) in the previous study revealed alleviated liver lipid accumulation in metabolic syndrome mice. The study aimed to investigate the mechanism of AEPL on saturated long-chain fatty acid-induced lipotoxicity in HepG2 cells. Moreover, the phytochemical composition of AEPL was identified in the present study. HepG2 cells treated with palmitic acid (PA) were used for exploring the effect of AEPL on lipid accumulation, apoptosis, ER stress, and antioxidant response. The chemical composition of AEPL was analyzed by HPLC-ESI-MS/MS. AEPL treatment reduced PA-induced ROS production and lipid accumulation. Further molecular results revealed that AEPL restored cytochrome c in mitochondria and decreased caspase 3 activity to cease apoptosis. In addition, AEPL in PA-stressed HepG2 cells significantly reduced the ER stress and suppressed SREBP-1 activation for decreasing lipogenesis. For defending PA-induced oxidative stress, AEPL promoted Nrf2 expression and its target genes, SOD1 and GPX3, expressions. The present study suggested that AEPL protected from PA-induced lipotoxicity through reducing ER stress, increasing antioxidant ability, and inhibiting apoptosis. The efficacy of AEPL on lipotoxicity was probably concerned with kaempferol and isorhamnetin derived compounds.

scholarly journals Exendin-4 improves ER stress-induced lipid accumulation and regulates lipin-1 signaling in HepG2 cells

2018 ◽  
Vol 23 (4) ◽  
pp. 629-638 ◽  
Author(s):  
Jinmi Lee ◽  
Seok-Woo Hong ◽  
Hyemi Kwon ◽  
Se Eun Park ◽  
Eun-Jung Rhee ◽  
...  
Keyword(s):  
Er Stress ◽  
Lipid Accumulation ◽  
Hepg2 Cells ◽  
Lipin 1

scholarly journals Alpha lipoic acid attenuates ER stress and improves glucose uptake through DNAJB3 cochaperone

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abdoulaye Diane ◽  
Naela Mahmoud ◽  
Ilham Bensmail ◽  
Namat Khattab ◽  
Hanan A. Abunada ◽  
...  
Keyword(s):  
Heat Shock ◽  
Er Stress ◽  
Glucose Uptake ◽  
Lipoic Acid ◽  
Heat Shock Response ◽  
Transcriptional Activation ◽  
Hepg2 Cells ◽  
Metabolic Stress ◽  
C2c12 Cells ◽  
Shock Response

AbstractPersistent ER stress, mitochondrial dysfunction and failure of the heat shock response (HSR) are fundamental hallmarks of insulin resistance (IR); one of the early core metabolic aberrations that leads to type 2 diabetes (T2D). The antioxidant α-lipoic acid (ALA) has been shown to attenuate metabolic stress and improve insulin sensitivity in part through activation of the heat shock response (HSR). However, these studies have been focused on a subset of heat shock proteins (HSPs). In the current investigation, we assessed whether ALA has an effect on modulating the expression of DNAJB3/HSP40 cochaperone; a potential therapeutic target with a novel role in mitigating metabolic stress and promoting insulin signaling. Treatment of C2C12 cells with 0.3 mM of ALA triggers a significant increase in the expression of DNAJB3 mRNA and protein. A similar increase in DNAJB3 mRNA was also observed in HepG2 cells. We next investigated the significance of such activation on endoplasmic reticulum (ER) stress and glucose uptake. ALA pre-treatment significantly reduced the expression of ER stress markers namely, GRP78, XBP1, sXBP1 and ATF4 in response to tunicamycin. In functional assays, ALA treatment abrogated significantly the tunicamycin-mediated transcriptional activation of ATF6 while it enhanced the insulin-stimulated glucose uptake and Glut4 translocation. Silencing the expression of DNAJB3 but not HSP72 abolished the protective effect of ALA on tunicamycin-induced ER stress, suggesting thus that DNAJB3 is a key mediator of ALA-alleviated tunicamycin-induced ER stress. Furthermore, the effect of ALA on insulin-stimulated glucose uptake is significantly reduced in C2C12 and HepG2 cells transfected with DNAJB3 siRNA. In summary, our results are supportive of an essential role of DNAJB3 as a molecular target through which ALA alleviates ER stress and improves glucose uptake.

scholarly journals Artemisia iwayomogiplusCurcuma longaSynergistically Ameliorates Nonalcoholic Steatohepatitis in HepG2 Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Hyeong-Geug Kim ◽  
Sung-Bae Lee ◽  
Jin-Seok Lee ◽  
Won-Young Kim ◽  
Seung-Hoon Choi ◽  
...  
Keyword(s):  
Er Stress ◽  
Nonalcoholic Steatohepatitis ◽  
Hepg2 Cells ◽  
Curcuma Longa ◽  
Water Extract ◽  
Underlying Mechanism ◽  
Liver Disorders ◽  
Artemisia Iwayomogi ◽  
Clinical Potential ◽  
Intracellular Triglyceride

The combination ofArtemisia iwayomogiandCurcuma longaradix is frequently prescribed for liver diseases in TKM. However, the synergic effects of the two herbs on nonalcoholic steatohepatitis (NASH) have not yet been studied. Therefore, we investigated the anti-NASH effects of the water extract ofA. iwayomogi(AI),C. longaradix (CL), and combination of the two herbs (ACE). Hepatic steatosis and NASH were induced in HepG2 cells by treatment with palmitic acid (PA, for 6 h) with/without pretreatment of ACE (25 or 50 μg/mL), AI (50 or 100 μg/mL), CL (50 or 100 μg/mL), curcumin (5 μg/mL), or scopoletin (5 μg/mL). The PA treatment (200 μM) drastically altered intracellular triglyceride levels, total cholesterol, and expression levels of genes related to lipid metabolism (CD36, SREBP1c, PPAR-γ, and PPAR-α), whereas pretreatment with ACE significantly attenuated these alterations. ACE also protected HepG2 cells from PA- (300 μM-) induced endoplasmic reticulum (ER) stress and apoptosis and attenuated the related key molecules including GRP78, eIF2, and CHOP, respectively. In conclusion, we found synergic effects ofA. iwayomogiandC. longaon NASH, supporting the clinical potential for fatty liver disorders. In addition, modulation of ER stress-relative molecules would be involved in its underlying mechanism.

scholarly journals Lipid-Induced Endoplasmic Reticulum Stress in Liver Cells Results in Two Distinct Outcomes: Adaptation with Enhanced Insulin Signaling or Insulin Resistance

Endocrinology ◽  
2012 ◽  
Vol 153 (5) ◽  
pp. 2164-2177 ◽  
Author(s):  
Caroline S. Achard ◽  
D. Ross Laybutt
Keyword(s):  
Insulin Resistance ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Insulin Signaling ◽  
Hepg2 Cells ◽  
Glycogen Synthesis ◽  
Liver Cells ◽  
Dependent Manner ◽  
Akt Phosphorylation ◽  
High Level

Chronically elevated fatty acids contribute to insulin resistance through poorly defined mechanisms. Endoplasmic reticulum (ER) stress and the subsequent unfolded protein response (UPR) have been implicated in lipid-induced insulin resistance. However, the UPR is also a fundamental mechanism required for cell adaptation and survival. We aimed to distinguish the adaptive and deleterious effects of lipid-induced ER stress on hepatic insulin action. Exposure of human hepatoma HepG2 cells or mouse primary hepatocytes to the saturated fatty acid palmitate enhanced ER stress in a dose-dependent manner. Strikingly, exposure of HepG2 cells to prolonged mild ER stress activation induced by low levels of thapsigargin, tunicamycin, or palmitate augmented insulin-stimulated Akt phosphorylation. This chronic mild ER stress subsequently attenuated the acute stress response to high-level palmitate challenge. In contrast, exposure of HepG2 cells or hepatocytes to severe ER stress induced by high levels of palmitate was associated with reduced insulin-stimulated Akt phosphorylation and glycogen synthesis, as well as increased expression of glucose-6-phosphatase. Attenuation of ER stress using chemical chaperones (trimethylamine N-oxide or tauroursodeoxycholic acid) partially protected against the lipid-induced changes in insulin signaling. These findings in liver cells suggest that mild ER stress associated with chronic low-level palmitate exposure induces an adaptive UPR that enhances insulin signaling and protects against the effects of high-level palmitate. However, in the absence of chronic adaptation, severe ER stress induced by high-level palmitate exposure induces deleterious UPR signaling that contributes to insulin resistance and metabolic dysregulation.

A Dipeptidyl Peptidase IV Inhibitory Peptide Relieves Palmitic Acid-Induced Endoplasmic Reticulum Stress in HepG2 Cells Independently of Inhibiting Dipeptidyl Peptidase IV Activity

2021 ◽  
Author(s):  
Ritian Jin ◽  
Haowei Ren ◽  
Minhe Liao ◽  
Jiaqi Shang ◽  
Dangfeng Wang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Palmitic Acid ◽  
Er Stress ◽  
Hepg2 Cells ◽  
Dipeptidyl Peptidase ◽  
Dipeptidyl Peptidase Iv ◽  
Inhibitory Peptide ◽  
Dpp Iv

The peptide VLATSGPG (VLA) is known to inhibit dipeptidyl peptidase IV (DPP-IV), although its mechanism in relieving endoplasmic reticulum (ER) stress is unclear. In this study, we found that treating...

scholarly journals Differential Lipotoxic Effects of Palmitate and Oleate in Activated Human Hepatic Stellate Cells and Epithelial Hepatoma Cells

2016 ◽  
Vol 39 (4) ◽  
pp. 1648-1662 ◽  
Author(s):  
Alexandra M. Hetherington ◽  
Cynthia G. Sawyez ◽  
Emma Zilberman ◽  
Alexandra M. Stoianov ◽  
Debra L. Robson ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Er Stress ◽  
Hepatic Stellate Cells ◽  
Hepg2 Cells ◽  
Stellate Cells ◽  
Hepatoma Cells ◽  
Surrounding Tissue ◽  
High Oleate ◽  
Activated Hepatic Stellate Cells

Background/Aims: Nonalcoholic fatty liver disease (NAFLD) progression to fibrosis, cirrhosis and hepatocellular carcinoma, alters the cellular composition of this organ. During late-stage NAFLD, fibrotic and possibly cancerous cells can proliferate and, like normal hepatocytes, are exposed to high concentrations of fatty acids from both surrounding tissue and circulating lipid sources. We hypothesized that primary human activated hepatic stellate cells and epithelial hepatoma (HepG2) cells respond differently to lipotoxic conditions, and investigated the mechanisms involved. Methods: Primary activated hepatic stellate cells and HepG2 cells were exposed to pathophysiological concentrations of fatty acids and comparative studies of lipid metabolic and stress response pathways were performed. Results: Both cell types remained proliferative during exposure to a combination of palmitate plus oleate reflective of the general saturated versus unsaturated fatty acid composition of western diets. However, exposure to either high palmitate or high oleate alone induced cytotoxicity in activated stellate cells, while only palmitate caused cytotoxicity in HepG2 cells. mRNA microarray and biochemical comparisons revealed that stellate cells stored markedly less fatty acids as neutral lipids, and had reduced capacity for beta-oxidation. Similar to previous observations in HepG2 cells, palmitate, but not oleate, induced ER stress and actin stress fiber formation in activated stellate cells. In contrast, oleate, but not palmitate, induced the inflammatory signal TXNIP, decreased cytoskeleton proteins, and decreased cell polarity preceding cell death in activated stellate cells. Conclusions: Palmitate-induced lipotoxicity was associated with ER stress pathways in both primary activated hepatic stellate cells and epithelial hepatoma cells, whereas high oleate caused lipotoxicity only in activated stellate cells, possibly through a distinct mechanism involving disruption of cytoskeleton components. This may have implications for optimal dietary fatty acid compositions during various stages of NAFLD.

scholarly journals Vildagliptin Can Alleviate Endoplasmic Reticulum Stress in the Liver Induced by a High Fat Diet

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Xiaoqing Ma ◽  
Wenhua Du ◽  
Shanshan Shao ◽  
Chunxiao Yu ◽  
Lingyan Zhou ◽  
...  
Keyword(s):  
Er Stress ◽  
High Fat Diet ◽  
Hepg2 Cells ◽  
Liver Weight ◽  
Chow Diet ◽  
High Fat ◽  
Western Blots ◽  
Nonalcoholic Fatty Liver ◽  
Expression Levels

Purpose. We investigated whether a DDP-4 inhibitor, vildagliptin, alleviated ER stress induced by a high fat diet and improved hepatic lipid deposition. Methods. C57BL/6 mice received standard chow diet (CD), high fat diet (HFD), and HFD administered with vildagliptin (50 mg/Kg) (V-HFD). After administration for 12 weeks, serum alanine aminotransferase, glucose, cholesterol, triglyceride, and insulin levels were analyzed. Samples of liver underwent histological examination and transmission electron microscopy, real-time PCR for gene expression levels, and western blots for protein expression levels. ER stress was induced in HepG2 cells with palmitic acid and the effects of vildagliptin were investigated. Results. HFD mice showed increased liver weight/body weight (20.27%) and liver triglycerides (314.75%) compared to CD mice, but these decreased by 9.27% and 21.83%, respectively, in V-HFD mice. In the liver, HFD induced the expression of ER stress indicators significantly, which were obviously decreased by vildagliptin. In vitro, the expressions of molecular indicators of ER stress were reduced in HepG2 when vildagliptin was administered. Conclusions. Vildagliptin alleviates hepatic ER stress in a mouse high fat diet model. In HepG2 cells, vildagliptin directly reduced ER stress. Therefore, vildagliptin may be a potential agent for nonalcoholic fatty liver disease.

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