Molecular basis for calcium signaling in hepatic stellate cells

2007 ◽  
Vol 292 (4) ◽  
pp. G975-G982 ◽  
Author(s):  
Emma A. Kruglov ◽  
Paulo R. A. V. Correa ◽  
Gaurav Arora ◽  
Jin Yu ◽  
Michael H. Nathanson ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Stellate Cells ◽  
P2y Receptors ◽  
Type I ◽  
Inositol 1,4,5 Trisphosphate ◽  
Trisphosphate Receptor ◽  
Healthy Liver ◽  
Organ Fibrosis ◽  
Injured Liver

Progressive liver fibrosis (with the resultant cirrhosis) is the primary cause of chronic liver failure. Hepatic stellate cells (HSCs) are critically important mediators of liver fibrosis. In the healthy liver, HSCs are quiescent lipid-storing cells limited to the perisinusoidal endothelium. However, in the injured liver, HSCs undergo myofibroblastic transdifferentiation (activation), which is a critical step in the development of organ fibrosis. HSCs express P2Y receptors linking extracellular ATP to inositol (1,4,5)-trisphosphate-mediated cytosolic Ca2+ signals. Here, we report that HSCs express only the type I inositol (1,4,5)-trisphosphate receptor and that the receptor shifts into the nucleus and cell extensions upon activation. These cell extensions, furthermore, express sufficient machinery to enable local application of ATP to evoke highly localized Ca2+ signals that induce localized contractions. These autonomous units of subcellular signaling and response reveal a new level of subcellular organization, which, in turn, establishes a novel paradigm for the local control of fibrogenesis in the liver.

scholarly journals Suberoylanilide hydroxamic acid suppresses hepatic stellate cells activation by HMGB1 dependent reduction of NF-κB1

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1362 ◽  
Author(s):  
Wenwen Wang ◽  
Min Yan ◽  
Qiuhong Ji ◽  
Jinbiao Lu ◽  
Yuhua Ji ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Hydroxamic Acid ◽  
Molecular Mechanisms ◽  
Stellate Cell ◽  
Smooth Muscle Actin ◽  
Cdna Array ◽  
Stellate Cells ◽  
Type I ◽  
Suberoylanilide Hydroxamic Acid

Hepatic stellate cells (HSCs) activation is essential to the pathogenesis of liver fibrosis. Exploring drugs targeting HSC activation is a promising anti-fibrotic strategy. In the present study, we found suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, prominently suppressed the activation phenotype of a human hepatic stellate cell line—LX2. The production of collagen type I andα-smooth muscle actin (α-SMA) as well as the proliferation and migration of LX2 cells were significantly reduced by SAHA treatment. To determine the molecular mechanisms underlying this suppression, genome wild gene regulation by SAHA was determined by Affymetrix 1.0 human cDNA array. Upon SAHA treatment, the abundance of 331 genes was up-regulated and 173 genes was down-regulated in LX2 cells. Bioinformatic analyses of these altered genes highlighted the high mobility group box 1 (HMGB1) pathway was one of the most relevant pathways that contributed to SAHA induced suppression of HSCs activation. Further studies demonstrated the increased acetylation of intracellular HMGB1 in SAHA treated HSCs, and this increasing is most likely to be responsible for SAHA induced down-regulation of nuclear factor kappa B1 (NF-κB1) and is one of the main underlying mechanisms for the therapeutic effect of SAHA for liver fibrosis.

scholarly journals LincRNA-p21 Inhibits the Wnt/β-Catenin Pathway in Activated Hepatic Stellate Cells via Sponging MicroRNA-17-5p

2017 ◽  
Vol 41 (5) ◽  
pp. 1970-1980 ◽  
Author(s):  
Fujun Yu ◽  
Yong Guo ◽  
Bicheng Chen ◽  
Liang Shi ◽  
Peihong Dong ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Noncoding Rna ◽  
Type I Collagen ◽  
Smooth Muscle Actin ◽  
Stellate Cells ◽  
Type I ◽  
Muscle Actin ◽  
Pathway Activity ◽  
Long Intergenic Noncoding Rna

Background/Aims: It is known that the activation of hepatic stellate cells (HSCs) is a pivotal step in the initiation and progression of liver fibrosis. Aberrant activated Wnt/β-catenin pathway is known to accelerate the development of liver fibrosis. microRNAs (miRNAs)-mediated Wnt/β-catenin pathway has been reported to be involved in HSC activation during liver fibrosis. However, whether long noncoding RNAs (lncRNAs) regulate Wnt/β-catenin pathway during HSC activation still remains unclear. Methods: Long intergenic noncoding RNA-p21 (lincRNA-p21) expression was detected in Salvianolic acid B (Sal B)-treated cells. Effects of lincRNA-p21 knockdown on HSC activation and Wnt/β-catenin pathway activity were analyzed in Sal B-treated cells. In lincRNA-p21-overexpressing cells, effects of miR-17-5p on HSC activation and Wnt/β-catenin pathway activity were examined. Results: LincRNA-p21 expression was up-regulated in HSCs after Sal B treatment. In primary HSCs, lincRNA-p21 expression was down-regulated at Day 5 relative to Day 2. Sal B-inhibited HSC activation including the reduction of cell proliferation, α-smooth muscle actin (α-SMA) and type I collagen was inhibited by lincRNA-p21 knockdown. Sal B-induced Wnt/β-catenin pathway inactivation was blocked down by loss of lincRNA-p21. Notably, lincRNA-p21, confirmed as a target of miR-17-5p, suppresses miR-17-5p level. Lack of the miR-17-5p binding site in lincRNA-p21 prevents the suppression of miR-17-5p expression. In addition, the suppression of HSC activation and Wnt/β-catenin pathway induced by lincRNA-p21 overexpression was almost inhibited by miR-17-5p. Conclusion: We demonstrate that lincRNA-p21-inhibited Wnt/β-catenin pathway is involved in the effects of Sal B on HSC activation and lincRNA-p21 suppresses HSC activation, at least in part, via miR-17-5p-mediated-Wnt/β-catenin pathway.

Involvement of TLR4 Signaling Regulated-COX2/PGE2 Axis in Liver Fibrosis Induced by Schistosoma japonicum Infection

2021 ◽  
Author(s):  
Lan Chen ◽  
Xiaofang Ji ◽  
Manni Wang ◽  
Xiaoyan Liao ◽  
Cuiying Liang ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Schistosoma Japonicum ◽  
Hepatic Stellate Cells ◽  
Hepatitis Virus ◽  
Stellate Cells ◽  
Type I ◽  
Tlr4 Signaling ◽  
Pathway Activation ◽  
Mice Liver

Abstract Background: The hepatic stellate cells (HSCs) activation plays pivotal role in hepatic inflammation and liver fibrosis.TLR4 pathway activation has been reported to be involved in mice liver fibrosis induced by hepatitis virus infection, alcohol abuse, biliary ligation, carbon tetrachloride 4 treatment and Schistosoma japonicum (Sj) infection. The effect and mechanisms of cyclooxygenase 2 (COX2)/prostanoid E2 (PGE2) axis on liver fibrosis induced by Sj are still unclear. Results: This study investigated the link between COX2/PGE2 axis and TLR4 signaling in the induction of liver fibrogenesis in mice during Sj infection and in vitro culturing hepatic stellate cells (HSCs) strain-LX-2. The COX2/PGE2 axis was positively related with Sj-induced liver fibrosis. TLR4 pathway activation stimulated the COX2/PGE2 axis, in Sj-infected mice andin lipopolysaccharide (LPS)-exposed cultured HSCs. Synthetic PGE2 activated culturing HSCs through up-regulating alpha smooth muscle actin (α-SMA) expression. In LPS-triggered HSCs, NS398, a COX2 inhibitor led to suppression of PGE2 synthesis and reduced expression of α-SMA and type I collagen (COL I). Conclusions: These results indicated firstly the positive association of COX2/PGE2 axis with liver fibrosis induced by Sj infection. TLR4 signaling may control COX2/PGE2 axis in Sj-infected mice liver and in vitro culturing HSCs at least partially. COX2/PGE2-EP2/EP4 axis might be good drug targets against liver fibrosis induced by Sj infection.

scholarly journals The role of Mesothelin signaling in Portal Fibroblasts in the pathogenesis of cholestatic liver fibrosis

2021 ◽  
Vol 8 ◽  
Author(s):  
Hiroaki Fuji ◽  
Grant Miller ◽  
Takahiro Nishio ◽  
Yukinori Koyama ◽  
Kevin Lam ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Liver Injury ◽  
Hepatic Stellate Cells ◽  
Inflammatory Responses ◽  
Stellate Cells ◽  
Collagen Type I ◽  
Type I ◽  
Fibrotic Liver ◽  
Portal Fibroblasts

Liver fibrosis develops in response to chronic toxic or cholestatic injury, and is characterized by apoptosis of damaged hepatocytes, development of inflammatory responses, and activation of Collagen Type I producing myofibroblasts that make liver fibrotic. Two major cell types, Hepatic Stellate Cells (HSCs) and Portal Fibroblasts (PFs) are the major source of hepatic myofibroblasts. Hepatotoxic liver injury activates Hepatic Stellate Cells (aHSCs) to become myofibroblasts, while cholestatic liver injury activates both aHSCs and Portal Fibroblasts (aPFs). aPFs comprise the major population of myofibroblasts at the onset of cholestatic injury, while aHSCs are increasingly activated with fibrosis progression. Here we summarize our current understanding of the role of aPFs in the pathogenesis of cholestatic fibrosis, their unique features, and outline the potential mechanism of targeting aPFs in fibrotic liver.

scholarly journals Epigenetically-Regulated MicroRNA-9-5p Suppresses the Activation of Hepatic Stellate Cells via TGFBR1 and TGFBR2

2017 ◽  
Vol 43 (6) ◽  
pp. 2242-2252 ◽  
Author(s):  
Fujun Yu ◽  
BiCheng Chen ◽  
XuFei Fan ◽  
Guojun Li ◽  
Peihong Dong ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Transforming Growth Factor ◽  
Luciferase Activity ◽  
Activity Index ◽  
Methylation Status ◽  
Stellate Cells ◽  
Type I ◽  
Dependent Manner ◽  
Tgf Β1

Background/Aims: Recently, microRNAs (miRNAs) have been demonstrated to act as regulators of activation of hepatic stellate cells (HSCs). It is well known that the main profibrogenic inducer transforming growth factor-β1 (TGF-β1) contributes to HSC activation, which is a key event in liver fibrosis. Increasing studies show that miR-9-5p is down-regulated in liver fibrosis and restoration of miR-9-5p limits HSC activation. However, the role of miR-9-5p in TGF-β1-induced HSC activation is still not clear. Methods: miR-9-5p expression was quantified using real-time PCR in chronic hepatitis B (CHB) patients and TGF-β1-treated LX-2 cells. In CHB patients, histological activity index (HAI) and fibrosis stages were assessed using the Ishak scoring system. Effects of miR-9-5p on liver fibrosis in vivo and in vitro were analyzed. Luciferase activity assays were performed to examine the binding of miR-9-5p to the 3′-untranslated region of type I TGF-β receptor (TGFBR1) as well as TGFBR2. Results: Compared with healthy controls, miR-9-5p was reduced in CHB patients. There was a lower miR-9-5p expression in CHB patients with higher fibrosis scores or HAI scores. miR-9-5p was down-regulated by TGF-β1 in a dose-dependent manner. TGF-β1-induced HSC activation including cell proliferation, α-SMA and collagen expression was blocked down by miR-9-5p. Notably, miR-9-5p ameliorates carbon tetrachloride-induced liver fibrosis. As determined by luciferase activity assays, TGFBR1 and TGFBR2 were targets of miR-9-5p. Further studies demonstrated that miR-9-5p inhibited TGF-β1/Smads pathway via TGFBR1 and TGFBR2. Interestingly, promoter methylation was responsible for miR-9-5p down-regulation in liver fibrosis. The relationship between miR-9-5p expression and methylation was confirmed in CHB patients and TGF-β1-treated cells. Conclusion: Our results demonstrate that miR-9-5p could inhibit TGF-β1-induced HSC activation through TGFBR1 and TGFBR2. Loss of miR-9-5p is associated with its methylation status in liver fibrosis.

scholarly journals PFKFB3 Promotes Liver Fibrosis by Regulating Aerobic Glycolysis of Hepatic Stellate Cells

2021 ◽  
Vol 21 (5) ◽  
Author(s):  
Ming-yu Zhou ◽  
Xue-ke Zhao ◽  
Tao Huang ◽  
Gao-liang Zou ◽  
Rui-Han Hu ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Liver Tissue ◽  
Aerobic Glycolysis ◽  
Glucose Consumption ◽  
Stellate Cells ◽  
Glycolytic Flux ◽  
Type I ◽  
Fibrotic Liver

Background: Hepatic stellate cells (HSCs) are the key effector cells in the occurrence and development of liver fibrosis, while aerobic glycolysis is one of the important metabolic characteristics of HSC activation. 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3) is a homodimeric bifunctional enzyme, which is a rate-limiting enzyme in glycolysis. This metabolite is important for the dynamic regulation of glycolytic flux. However, little is known about the role of PFKFB3 in liver fibrosis. Objectives: In this study, we aimed to explore the effects of PFKFB3 on aerobic glycolysis in the process of HSC trans-differentiation and liver fibrosis. Methods: Immunohistochemical (IHC) staining and immunofluorescence assays were used to examine PFKFB3 expression in mice fibrotic liver tissue. The determination of extracellular acidification rate was used to examine changes in aerobic glycolytic flux, lactate production levels, and glucose consumption levels in HSCs upon TGF-β1 stimulation. Western blot analysis of the expression of PFKFB3, α-SMA protein, and type I collagen was done. Liver histopathology was also examined. Besides, glycolytic inhibition by pharmacologic approaches was used to demonstrate the critical role of glycolysis in liver fibrosis. Results: The PFKFB3 protein expression was increased in mouse fibrotic liver tissue. In addition, immunofluorescence revealed the colocalization of PFKFB3 and alpha-smooth muscle actin (α-SMA) protein. In vitro experiments showed that PFKFB3 could promote glycolysis flux, lactic acid production, and glucose consumption of hepatic stellate cells. The PFKFB3 inhibitor was used in a mouse model of liver fibrosis, and the inhibition of PFKFB3 reduced the degree of liver inflammation and liver fibrosis. Conclusions: PFKFB3 can promote HSC aerobic glycolysis, which, in turn, promotes HSC activation and liver fibrosis.

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