scholarly journals Proteomics of lipid accumulation and DGAT inhibition in HepG2 liver carcinoma cells

2021 ◽  
Author(s):  
◽  
Bhumika Bhatt-Wessel
Keyword(s):  
Cell Proliferation ◽  
Disease Progression ◽  
Lipid Accumulation ◽  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Cellular Damage ◽  
Liver Carcinoma ◽  
Alcoholic Fatty Liver ◽  
The Metabolic Syndrome ◽  
Treated Sample

<p>Non-alcoholic fatty liver disease (NAFLD) is a manifestation of the metabolic syndrome in the liver. It is marked by hepatocyte accumulation of triacylglycerol (TAG) rich lipid droplets. In some patients, the disease progresses to non-alcoholic steatohepatitis (NASH), characterized by cellular damage, inflammation and fibrosis. In some cases, cirrhosis and liver failure may occur. However, the pathogenesis of NAFLD is still unclear. The present project is based on the hypothesis that hepatocytes are equipped with mechanisms that allow them to manage lipid accumulation to a certain extent. Continued or increased lipid accumulation beyond this triggers molecular mechanisms such as oxidative stress, lipid peroxidation and cell death that aggravate the condition and cause disease progression. The aim of this project is to study the effects of lipid accumulation on the cells using proteomics approach to identify proteins involved in the disease progression.  A cell culture model was used in the study. HepG2 cells, a human liver carcinoma cell line, were treated with a mixture of fatty acids (FA) to induce lipid accumulation. The lipid accumulation in HepG2 cells was measured with Oil red O assay and the effect of lipid accumulation on the proliferation of the cells was measured using an MTT cell proliferation assay. HepG2 cells treated with 1 mM FA mixture for 6 hours induced lipid accumulation 1.4 times of control with 90% of cell proliferation capacity of the control cells.  The final and the only committed step in TAG biosynthesis is catalysed by acyl-CoA diacylglycerol acyltransferase (DGAT) enzymes. To investigate if limiting lipid accumulation in HepG2 cells would prevent molecular mechanisms of pathogenesis, inhibition of DGAT by small molecule inhibitors was performed. Among the three DGAT inhibitors (A922500, PF06424439 and PF04620110) tested, PF04620110 reduced the lipid accumulation to 1.2 fold of the control cells when they were treated with 100 μM of the inhibitor in the presence of 1 mM FA mixture for 6 h.  Proteomic analyses were carried out for the control, FA-treated and inhibitor-treated cell groups to identify protein changes in the abundance. Functional analyses of the changed proteins identified suggest that lipid accumulation tends to adversely affect the functioning of the ER and the mitochondria. A complex interplay between the two organelles, possibly mediated by Ca2+ signalling may be vital in ensuring cell survival. PF04620110 was able to counter the FA induced changes in the abundance of some proteins involved in the metabolic processes but it had limited effect on the ER chaperones whose abundance in the inhibitor-treated sample was comparable to that of the FA-treated sample. These data provided important information for future discoveries of biomarkers and molecular mechanisms involved in the progression of NAFLD.</p>

scholarly journals Proteomics of lipid accumulation and DGAT inhibition in HepG2 liver carcinoma cells

2021 ◽  
Author(s):  
◽  
Bhumika Bhatt-Wessel
Keyword(s):  
Cell Proliferation ◽  
Disease Progression ◽  
Lipid Accumulation ◽  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Cellular Damage ◽  
Liver Carcinoma ◽  
Alcoholic Fatty Liver ◽  
The Metabolic Syndrome ◽  
Treated Sample

<p>Non-alcoholic fatty liver disease (NAFLD) is a manifestation of the metabolic syndrome in the liver. It is marked by hepatocyte accumulation of triacylglycerol (TAG) rich lipid droplets. In some patients, the disease progresses to non-alcoholic steatohepatitis (NASH), characterized by cellular damage, inflammation and fibrosis. In some cases, cirrhosis and liver failure may occur. However, the pathogenesis of NAFLD is still unclear. The present project is based on the hypothesis that hepatocytes are equipped with mechanisms that allow them to manage lipid accumulation to a certain extent. Continued or increased lipid accumulation beyond this triggers molecular mechanisms such as oxidative stress, lipid peroxidation and cell death that aggravate the condition and cause disease progression. The aim of this project is to study the effects of lipid accumulation on the cells using proteomics approach to identify proteins involved in the disease progression.  A cell culture model was used in the study. HepG2 cells, a human liver carcinoma cell line, were treated with a mixture of fatty acids (FA) to induce lipid accumulation. The lipid accumulation in HepG2 cells was measured with Oil red O assay and the effect of lipid accumulation on the proliferation of the cells was measured using an MTT cell proliferation assay. HepG2 cells treated with 1 mM FA mixture for 6 hours induced lipid accumulation 1.4 times of control with 90% of cell proliferation capacity of the control cells.  The final and the only committed step in TAG biosynthesis is catalysed by acyl-CoA diacylglycerol acyltransferase (DGAT) enzymes. To investigate if limiting lipid accumulation in HepG2 cells would prevent molecular mechanisms of pathogenesis, inhibition of DGAT by small molecule inhibitors was performed. Among the three DGAT inhibitors (A922500, PF06424439 and PF04620110) tested, PF04620110 reduced the lipid accumulation to 1.2 fold of the control cells when they were treated with 100 μM of the inhibitor in the presence of 1 mM FA mixture for 6 h.  Proteomic analyses were carried out for the control, FA-treated and inhibitor-treated cell groups to identify protein changes in the abundance. Functional analyses of the changed proteins identified suggest that lipid accumulation tends to adversely affect the functioning of the ER and the mitochondria. A complex interplay between the two organelles, possibly mediated by Ca2+ signalling may be vital in ensuring cell survival. PF04620110 was able to counter the FA induced changes in the abundance of some proteins involved in the metabolic processes but it had limited effect on the ER chaperones whose abundance in the inhibitor-treated sample was comparable to that of the FA-treated sample. These data provided important information for future discoveries of biomarkers and molecular mechanisms involved in the progression of NAFLD.</p>

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

Polyphenols: Novel Signaling Pathways

2018 ◽  
Vol 24 (2) ◽  
pp. 158-170 ◽  
Author(s):  
Marie-Louise Ricketts ◽  
Bradley S. Ferguson
Keyword(s):  
Risk Factors ◽  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Density Lipoprotein ◽  
Mechanisms Of Action ◽  
Metabolic Effects ◽  
Special Focus ◽  
In Vivo Models ◽  
Alcoholic Fatty Liver ◽  
The Metabolic Syndrome

Background: Cardiovascular disease (CVD) is currently the leading cause of death globally. The metabolic syndrome (MetS), a clustering of risk factors including hypertension, hyperglycemia, elevated low-density lipoprotein (LDL) cholesterol, reduced high-density lipoprotein (HDL) cholesterol and increased visceral adiposity, is a significant risk factor for the development of CVD. Non-alcoholic fatty liver disease (NAFLD), often referred to as the hepatic manifestation of MetS, is a constellation of progressive liver disorders closely linked to obesity, diabetes, and insulin resistance. NAFLD initially presents as relatively benign, non-progressive hepatic steatosis, but it may, in certain individuals, progress to nonalcoholic steatohepatitis, fibrosis, cirrhosis, or hepatocellular carcinoma. Currently, there are no validated treatments for NAFLD. Polyphenols are important bioactive dietary compounds and may represent a natural complementary and integrative therapy for the treatment of CVDassociated risk factors, including elevated serum cholesterol and triglyceride levels, as well as NAFLD. Understanding their molecular mechanisms of action is important in the design of future human intervention studies. Methods: Several studies utilizing in vitro and in vivo models have helped to identify underlying molecular mechanisms of action of polyphenols. Results: This review will highlight recent advances regarding the molecular actions of dietary procyanidins, with a special focus on those originating from procyanidin-rich grape seed extracts, with a focus on the signaling pathways utilized to exert beneficial metabolic effects. Conclusion: Modulation of nuclear receptor activity and histone deacetylase inhibition has been identified as underlying mechanisms contributing to procyanidin-mediated amelioration of dyslipidemia and steatosis.

scholarly journals A Role for Gut Microbiome Fermentative Pathways in Fatty Liver Disease Progression

2020 ◽  
Vol 9 (5) ◽  
pp. 1369 ◽  
Author(s):  
Paula Iruzubieta ◽  
Juan M. Medina ◽  
Raúl Fernández-López ◽  
Javier Crespo ◽  
Fernando de la Cruz
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Disease Progression ◽  
Gut Microbiome ◽  
Fatty Liver Disease ◽  
Molecular Mechanisms ◽  
Alcohol Fermentation ◽  
Alcoholic Fatty Liver ◽  
Liver Disease Progression ◽  
The Impact

Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disease in which environmental and genetic factors are involved. Although the molecular mechanisms involved in NAFLD onset and progression are not completely understood, the gut microbiome (GM) is thought to play a key role in the process, influencing multiple physiological functions. GM alterations in diversity and composition directly impact disease states with an inflammatory course, such as non-alcoholic steatohepatitis (NASH). However, how the GM influences liver disease susceptibility is largely unknown. Similarly, the impact of strategies targeting the GM for the treatment of NASH remains to be evaluated. This review provides a broad insight into the role of gut microbiota in NASH pathogenesis, as a diagnostic tool, and as a therapeutic target in this liver disease. We highlight the idea that the balance in metabolic fermentations can be key in maintaining liver homeostasis. We propose that an overabundance of alcohol-fermentation pathways in the GM may outcompete healthier, acid-producing members of the microbiota. In this way, GM ecology may precipitate a self-sustaining vicious cycle, boosting liver disease progression.

scholarly journals Phloretin ameliorates hepatic steatosis through regulation of lipogenesis and Sirt1/AMPK signaling in obese mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chian-Jiun Liou ◽  
Shu-Ju Wu ◽  
Szu-Chuan Shen ◽  
Li-Chen Chen ◽  
Ya-Ling Chen ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Fatty Acid ◽  
Hepatic Steatosis ◽  
Lipid Accumulation ◽  
Hepg2 Cells ◽  
Fatty Acid Synthase ◽  
Regulatory Element ◽  
Liver Lipid ◽  
Obese Mice ◽  
Alcoholic Fatty Liver

Abstract Background Phloretin is isolated from apple trees and could increase lipolysis in 3T3-L1 adipocytes. Previous studies have found that phloretin could prevent obesity in mice. In this study, we investigated whether phloretin ameliorates non-alcoholic fatty liver disease (NAFLD) in high-fat diet (HFD)-induced obese mice, and evaluated the regulation of lipid metabolism in hepatocytes. Methods HepG2 cells were treated with 0.5 mM oleic acid to induce lipid accumulation, and then treated with phloretin to evaluate the molecular mechanism of lipogenesis. In another experiment, male C57BL/6 mice were fed normal diet or HFD (60% fat, w/w) for 16 weeks. After the fourth week, mice were treated with or without phloretin by intraperitoneal injection for 12 weeks. Results Phloretin significantly reduced excessive lipid accumulation and decreased sterol regulatory element-binding protein 1c, blocking the expression of fatty acid synthase in oleic acid-induced HepG2 cells. Phloretin increased Sirt1, and phosphorylation of AMP activated protein kinase to suppress acetyl-CoA carboxylase expression, reducing fatty acid synthesis in hepatocytes. Phloretin also reduced body weight and fat weight compared to untreated HFD-fed mice. Phloretin also reduced liver weight and liver lipid accumulation and improved hepatocyte steatosis in obese mice. In liver tissue from obese mice, phloretin suppressed transcription factors of lipogenesis and fatty acid synthase, and increased lipolysis and fatty acid β-oxidation. Furthermore, phloretin regulated serum leptin, adiponectin, triglyceride, low-density lipoprotein, and free fatty acid levels in obese mice. Conclusions These findings suggest that phloretin improves hepatic steatosis by regulating lipogenesis and the Sirt-1/AMPK pathway in the liver.

Houttuynia cordata Attenuates Lipid Accumulation via Activation of AMP-Activated Protein Kinase Signaling Pathway in HepG2 Cells

2014 ◽  
Vol 42 (03) ◽  
pp. 651-664 ◽  
Author(s):  
Hyun Kang ◽  
Sushruta Koppula
Keyword(s):  
Protein Kinase ◽  
High Glucose ◽  
Lipid Accumulation ◽  
Hepg2 Cells ◽  
Fatty Acid Synthase ◽  
Molecular Mechanisms ◽  
Regulatory Element ◽  
Adenosine Monophosphate ◽  
Perennial Herb ◽  
Houttuynia Cordata

Houttuynia cordata (H. cordata) from the family Saururaceae is a perennial herb native to Southeast Asia. It possesses a range of medicinal properties to treat several disease symptoms including allergic inflammation and anaphylaxis. In the present investigation, we provided the molecular mechanisms underlying the role of H. cordata extract (HCE) in the prevention of high glucose-induced lipid accumulation in human HepG2 hepatocytes. HepG2 cells were pre-treated with various concentrations of HCE (0, 10, 20, 40, and 80 μg/mL) and treated with serum-free medium with normal glucose (5 mM) for 1 h, followed by exposure to high glucose (25 mM D-glucose) for 24 h. HCE significantly and dose-dependently attenuated lipid accumulation in human HepG2 hepatocytes when exposed to high glucose (25 mM D-glucose) (p < 0.05, p < 0.01 and p < 0.001 at 20, 40, and 80 μg/mL concentrations, respectively). Further, HCE attenuated the expression of fatty acid synthase (FAS), sterol regulatory element-binding protein-1 and glycerol 3-phosphate acyltransferases (GPATs). The adenosine monophosphate-activated protein kinase (AMPK) was also activated by HCE treatment when exposed to high glucose (25 mM D-glucose) in human HepG2 hepatocytes. This study suggests the hypolipidemic effects of HCE by the inhibition of lipid biosynthesis mediated through AMPK signaling, which may play an active role and can be developed as an anti-obesity agent.

scholarly journals Playing Jekyll and Hyde—The Dual Role of Lipids in Fatty Liver Disease

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2244
Author(s):  
Martijn R. Molenaar ◽  
Louis C. Penning ◽  
J. Bernd Helms
Keyword(s):  
Lipid Metabolism ◽  
Liver Disease ◽  
Fatty Liver ◽  
Hepatic Fibrosis ◽  
Lipid Accumulation ◽  
Fatty Liver Disease ◽  
Molecular Mechanisms ◽  
Stellate Cells ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid Accumulation

Lipids play Jekyll and Hyde in the liver. On the one hand, the lipid-laden status of hepatic stellate cells is a hallmark of healthy liver. On the other hand, the opposite is true for lipid-laden hepatocytes—they obstruct liver function. Neglected lipid accumulation in hepatocytes can progress into hepatic fibrosis, a condition induced by the activation of stellate cells. In their resting state, these cells store substantial quantities of fat-soluble vitamin A (retinyl esters) in large lipid droplets. During activation, these lipid organelles are gradually degraded. Hence, treatment of fatty liver disease is treading a tightrope—unsophisticated targeting of hepatic lipid accumulation might trigger problematic side effects on stellate cells. Therefore, it is of great importance to gain more insight into the highly dynamic lipid metabolism of hepatocytes and stellate cells in both quiescent and activated states. In this review, part of the special issue entitled “Cellular and Molecular Mechanisms underlying the Pathogenesis of Hepatic Fibrosis 2020”, we discuss current and highly versatile aspects of neutral lipid metabolism in the pathogenesis of non-alcoholic fatty liver disease (NAFLD).

scholarly journals Kaempferol-3-O-Glucuronide Ameliorates Non-Alcoholic Steatohepatitis in High-Cholesterol-Diet-Induced Larval Zebrafish and HepG2 Cell Models via Regulating Oxidation Stress

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 445
Author(s):  
Yang Deng ◽  
Ji Ma ◽  
Xin Weng ◽  
Yuqin Wang ◽  
Maoru Li ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lipid Accumulation ◽  
Hepg2 Cells ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
Zebrafish Model ◽  
Alcoholic Fatty Liver ◽  
Larval Zebrafish

NAFLD (non-alcoholic fatty liver disease) is one of the most prominent liver diseases in the world. As a metabolic-related disease, the development of NAFLD is closely associated with various degrees of lipid accumulation, oxidation, inflammation, and fibrosis. Ilex chinensis Sims is a form of traditional Chinese medicine which is used to treat bronchitis, burns, pneumonia, ulceration, and chilblains. Kaempferol-3-O-glucuronide (K3O) is a natural chemical present in Ilex chinensis Sims. This study was designed to investigate the antioxidative, fat metabolism-regulating, and anti-inflammatory potential of K3O. A high-cholesterol diet (HCD) was used to establish steatosis in larval zebrafish, whereby 1mM free fatty acid (FFA) was used to induce lipid accumulation in HepG2 cells, while H2O2 was used to induce oxidative stress in HepG2. The results of this experiment showed that K3O reduced lipid accumulation and the level of reactive oxygen species (ROS) both in vivo (K3O, 40μM) and in vitro (K3O, 20μM). Additionally, K3O (40μM) reduced neutrophil aggregation in vivo. K3O (20μM) also decreased the level of malondialdehyde (MDA) and significantly increased the level of glutathione peroxidase (GSH-px) in both the HCD-induced larval zebrafish model and H2O2-exposed HepG2 cells. In the mechanism study, keap1, nrf2, tnf-α, and il-6 mRNA were all significantly reversed by K3O (20μM) in zebrafish. Changes in Keap1 and Nrf2 mRNA expression were also detected in H2O2-exposed HepG2 cells after they were treated with K3O (20μM). In conclusion, K3O exhibited a reduction in oxidative stress and lipid peroxidation, and this may be related to the Nrf2/Keap1 pathway in the NAFLD larval zebrafish model.

scholarly journals (+)-Dehydrovomifoliol Alleviates Oleic Acid-Induced Lipid Accumulation in HepG2 Cells via the PPARα–FGF21 Pathway

2021 ◽  
Vol 12 ◽  
Author(s):  
Yiyuan Xi ◽  
Jujia Zheng ◽  
Wei Xie ◽  
Xiangwei Xu ◽  
Namki Cho ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Lipid Accumulation ◽  
Hepg2 Cells ◽  
New Drugs ◽  
Acid Oxidation ◽  
Alcoholic Fatty Liver ◽  
Protein Levels ◽  
Artemisia Frigida

An overload of hepatic fatty acids, such as oleic acid is a key trigger of non-alcoholic fatty liver disease (NAFLD). Here, we investigated whether Artemisia frigida, a valuable traditional medicine used to treat various diseases, could mitigate OA-induced lipid accumulation in HepG2 cells. Then, to identify the active substances in A. frigida, a phytochemistry investigation was conducted using a bioassay-guided isolation method. Consequently, one terpene (1) and one flavone (2) were identified. Compound 1 ((+)-dehydrovomifoliol) exhibited potent effects against lipid accumulation in OA-induced HepG2 cells, without causing cyto-toxicity. Notably, treatment with (+)-dehydrovomifoliol decreased the expression levels of three genes related to lipogenesis (SREBP1, ACC, and FASN) and increased those of three genes related to fatty acid oxidation (PPARα, ACOX1, and FGF21). In addition, similar results were observed for SREBP1, PPARα, and FGF21 protein levels. The effects of (+)-dehydrovomifoliol were partially reversed by treatment with the PPARα antagonist GW6471, indicating the important role of the PPARα–FGF21 axis in the effects of (+)-dehydrovomifoliol. Based on its effects on hepatic lipogenesis and fatty acid oxidation signaling via the PPARα–FGF21 axis, (+)-dehydrovomifoliol isolated from A. frigida could be a useful early lead compound for developing new drugs for NAFLD prevention.

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