scholarly journals Long-Term Exposure to Low-Dose Di-(2-ethylhexyl) Phthalate Impairs Cholesterol Metabolism in Hepatic Stellate Cells and Exacerbates Liver Fibrosis

2020 ◽  
Vol 17 (11) ◽  
pp. 3802
Author(s):  
Chun-Ya Lee ◽  
Fat-Moon Suk ◽  
Yuh-Ching Twu ◽  
Yi-Jen Liao
Keyword(s):  
Liver Fibrosis ◽  
Liver Damage ◽  
Hepatic Stellate Cells ◽  
Low Dose ◽  
Cholesterol Metabolism ◽  
Mapk Pathway ◽  
Stellate Cells ◽  
Major Incident ◽  
Ethylhexyl Phthalate

Phthalates are often added to plastic products to increase their flexibility. Di-(2-ethylhexyl) phthalate (DEHP) is one of the most common plasticizers. Previously, a major incident involving phthalate-contaminated foodstuffs occurred, where phthalates were deliberately added to foodstuffs as a substitute for emulsifiers, resulting in a threat to public health. DEHP exposure can cause liver damage and further lead to cancer; however, the effects of long-term exposure to low-dose DEHP on hepatic stellate cells (HSCs) and on liver fibrosis are still unclear. In this study, we showed that chronic exposure to low-dose DEHP results in an accumulation of cholesterol in HSCs by disturbing the cholesterol metabolism and enhancing endogenous cholesterol synthesis. In addition, long-term exposure to low-dose DEHP reduces the sensitivity of HSCs to platelet-derived growth factor BB (PDGF-BB)-induced proliferation by blocking the MAPK pathway. Dysfunction of mitochondrial respiration and induction of caspase 3/PARP-dependent apoptosis were observed in HSCs following chronic, low-dose exposure. The carbon tetrachloride (CCl4)-induced liver fibrosis mouse model showed that long-term administration of DEHP significantly promoted liver damage, inflammatory infiltration, cholesterol accumulation, and deposition of hepatic collagen. In conclusion, long-term exposure to low-dose DEHP may perturb the cholesterol metabolism in HSCs and accelerate liver damage and fibrosis.

scholarly journals Effect of High Concentrations of Fructose on the Expression of TGF-β and α-SMA Genes in Human Hepatic Stellate Cells

2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Elham Shakerian ◽  
Hamid Yaghooti ◽  
Alireza Kheirollah ◽  
Narges Mohammadtaghvaei
Keyword(s):  
Liver Fibrosis ◽  
Mrna Expression ◽  
Liver Damage ◽  
Hepatic Stellate Cells ◽  
Stellate Cells ◽  
Control Group ◽  
Chronic Liver Damage ◽  
Fructose Intake ◽  
High Fructose ◽  
Human Hscs

Background: Liver fibrosis is a reversible response to wound-healing that occurs in most forms of chronic liver damage, beginning with the activation of hepatic stellate cells (HSCs). The increased expression of genes, such as beta-converting growth factor (TGF-β) and actin-alpha smooth muscle (α-SMA) indicates the activation of HSCs. During liver damage, HSCs are activated and converted to myofibroblasts. As a result, the expression of TGF-β and αSMA genes in HSCs increases and leads to liver fibrosis. High fructose intake is known to have harmful effects on human health. Due to the persistent increase in high fructose intake via many beverages and foods in industrialized countries, much concern has been raised about the effect of fructose on liver damage, but its role in activating human HSCs has not been studied. Objectives: We aimed to investigate the effect of high fructose concentration on human HSCs activation by measuring the level of mRNA expression of TGF-β and α-SMA genes involved in liver fibrosis. Methods: Human HSCs were cultured in Dulbecco’s Modified Eagle’s Medium (DMEM) plus 10% Fetal Bovine Serum (FBS) at 37°C in 5% CO2. Cells were incubated in media containing 25 and 30 mM fructose for 48 h. The control group was incubated in DMEM without fructose. The cells were serum-starved for 24 h before treatment. Then, the total RNA was extracted, reversely transcribed into cDNA, and underwent Quantitative Real-time PCR (qRT-PCR). Results: The results indicated that the mRNA expression of TGF-β and αSMA genes significantly increased by treating with 25 and 30 mM fructose in HSCs when compared to the control group (P < 0.05). Conclusions: The increase in the mRNA of TGF-β and αSMA genes is used as a standard marker for HSC activation, leading to liver fibrosis. The results demonstrated that high fructose concentration could activate HSCs and increase the levels of TGF-β and αSMA in these cells. Thus, controlling fructose consumption and identifying the mechanism of fructose action is important to treat and reduce liver injury.

scholarly journals Selonsertib Inhibits Liver Fibrosis via Downregulation of ASK1/ MAPK Pathway of Hepatic Stellate Cells

2020 ◽  
Vol 28 (6) ◽  
pp. 527-536
Author(s):  
Young-Chan Yoon ◽  
Zhenghuan Fang ◽  
Ji Eun Lee ◽  
Jung Hee Park ◽  
Ji-Kan Ryu ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Mapk Pathway ◽  
Stellate Cells

scholarly journals Transcriptional repression of SIRT1 by protein inhibitor of activated STAT 4 (PIAS4) in hepatic stellate cells contributes to liver fibrosis

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Lina Sun ◽  
Zhiwen Fan ◽  
Junliang Chen ◽  
Wenfang Tian ◽  
Min Li ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
High Glucose ◽  
Interstitial Fibrosis ◽  
Stellate Cells ◽  
Quiescent State ◽  
Dependent Manner ◽  
Gene Promoters ◽  
Sirt1 Expression ◽  
Primary Mouse

Abstract Interstitial fibrosis represents a key pathological process in non-alcoholic steatohepatitis (NASH). In the liver, fibrogenesis is primarily mediated by activated hepatic stellate cells (HSCs) transitioning from a quiescent state in response to a host of stimuli. The molecular mechanism underlying HSC activation is not completely understood. Here we report that there was a simultaneous up-regulation of PIAS4 expression and down-regulation of SIRT1 expression accompanying increased hepatic fibrogenesis in an MCD-diet induced mouse model of NASH. In cultured primary mouse HSCs, stimulation with high glucose activated PIAS4 while at the same time repressed SIRT1. Over-expression of PIAS4 directly repressed SIRT1 promoter activity. In contrast, depletion of PIAS4 restored SIRT1 expression in HSCs treated with high glucose. Estrogen, a known NASH-protective hormone, antagonized HSC activation by targeting PIAS4. Lentivirus-mediated delivery of short hairpin RNA (shRNA) targeting PIAS4 in mice ameliorated MCD diet induced liver fibrosis by normalizing SIRT1 expression in vivo. PIAS4 promoted HSC activation in a SIRT1-dependent manner in vitro. Mechanistically, PIAS4 mediated SIRT1 repression led to SMAD3 hyperacetylation and enhanced SMAD3 binding to fibrogenic gene promoters. Taken together, our data suggest SIRT1 trans-repression by PIAS4 plays an important role in HSC activation and liver fibrosis.

Norepinephrine induces calcium spikes and proinflammatory actions in human hepatic stellate cells

2006 ◽  
Vol 291 (5) ◽  
pp. G877-G884 ◽  
Author(s):  
Pau Sancho-Bru ◽  
Ramón Bataller ◽  
Jordi Colmenero ◽  
Xavier Gasull ◽  
Montserrat Moreno ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Portal Hypertension ◽  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
Stellate Cells ◽  
Luciferase Reporter ◽  
Dependent Manner ◽  
Cell Contraction

Catecholamines participate in the pathogenesis of portal hypertension and liver fibrosis through α1-adrenoceptors. However, the underlying cellular and molecular mechanisms are largely unknown. Here, we investigated the effects of norepinephrine (NE) on human hepatic stellate cells (HSC), which exert vasoactive, inflammatory, and fibrogenic actions in the injured liver. Adrenoceptor expression was assessed in human HSC by RT-PCR and immunocytochemistry. Intracellular Ca2+ concentration ([Ca2+]i) was studied in fura-2-loaded cells. Cell contraction was studied by assessing wrinkle formation and myosin light chain II (MLC II) phosphorylation. Cell proliferation and collagen-α1(I) expression were assessed by [3H]thymidine incorporation and quantitative PCR, respectively. NF-κB activation was assessed by luciferase reporter gene and p65 nuclear translocation. Chemokine secretion was assessed by ELISA. Normal human livers expressed α1A-adrenoceptors, which were markedly upregulated in livers with advanced fibrosis. Activated human HSC expressed α1A-adrenoceptors. NE induced multiple rapid [Ca2+]i oscillations (Ca2+ spikes). Prazosin (α1-blocker) completely prevented NE-induced Ca2+ spikes, whereas propranolol (nonspecific β-blocker) partially attenuated this effect. NE caused phosphorylation of MLC II and cell contraction. In contrast, NE did not affect cell proliferation or collagen-α1(I) expression. Importantly, NE stimulated the secretion of inflammatory chemokines (RANTES and interleukin-8) in a dose-dependent manner. Prazosin blocked NE-induced chemokine secretion. NE stimulated NF-κB activation. BAY 11-7082, a specific NF-κB inhibitor, blocked NE-induced chemokine secretion. We conclude that NE stimulates NF-κB and induces cell contraction and proinflammatory effects in human HSC. Catecholamines may participate in the pathogenesis of portal hypertension and liver fibrosis by targeting HSC.

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