Transforming growth factor beta-induced Foxo3a acts as a profibrotic mediator in hepatic stellate cells

Author(s):  
Seung Jung Kim ◽  
Kyu Min Kim ◽  
Ji Hye Yang ◽  
Sam Seok Cho ◽  
Eun Hee Jeong ◽  
...  

Abstract Hepatic stellate cells (HSCs) are major contributors to hepatic fibrogenesis facilitating liver fibrosis. FoxO3a is a member of the forkhead transcription factor family, which mediates cell proliferation and differentiation. However, the expression and function of FoxO3a during HSC activation remain largely unknown. FoxO3a overexpression was related to fibrosis in patients, and its expression was colocalized with desmin or α-smooth muscle actin, representative HSC markers. We also observed upregulated FoxO3a levels in two animal hepatic fibrosis models, a carbon tetrachloride (CCl4)-injected model and a bile duct ligation model. In addition, TGF-β treatment in mouse primary HSCs or LX-2 cells elevated FoxO3a expression. When FoxO3a was upregulated by TGF-β in LX-2 cells, both the cytosolic and nuclear levels of FoxO3a increased. In addition, we found that the induction of FoxO3a by TGF-β was due to both transcriptional and proteasome-dependent mechanisms. Moreover, FoxO3a overexpression promoted TGF-β-mediated Smad activation. Furthermore, FoxO3a increased fibrogenic gene expression, which was reversed by FoxO3a knockdown. TGF-β-mediated FoxO3a overexpression in HSCs facilitated hepatic fibrogenesis, suggesting that FoxO3a may be a novel target for liver fibrosis prevention and treatment.

2019 ◽  
Vol 97 (5) ◽  
pp. 505-512 ◽  
Author(s):  
Peiqin Wang ◽  
Shujuan Lei ◽  
Xiaohang Wang ◽  
Wenping Xu ◽  
Pingfang Hu ◽  
...  

Aberrant expression of microRNAs is associated with liver fibrogenesis. We previously found that microRNA-134 (miR-134) expression was reduced in fibrosis-based hepatocarcinogenesis induced by diethylinitrosamine. Herein we investigate the role and mechanisms of miR-134 in hepatic fibrosis. Our data show that miR-134 expression is reduced in rat hepatic fibrogenesis induced by carbontetrachloride, bile duct ligation, and dimethylnitrosamine, as well as in activated hepatic stellate cells (HSCs). Moreover, miR-134 inhibited HSC proliferation, and decreased the expression of smooth muscle actin and collagen I in HSCs, whereas the miR-134 inhibitor increased HSC activation. MiR-134 also negatively regulated transforming growth factor-β-activated kinase 1-binding protein 1 (TAB1) expression in both human and rat HSCs by directly binding to its 3′ untranslated region. Importantly, TAB1 expression was significantly elevated during liver fibrogenesis and HSC activation. Knockdown of TAB1 inhibited the proliferation and fibrogenic behavior of HSCs, and significantly reduced the effect of the miR-134 inhibitor on HSC proliferation. Collectively, these data suggest that miR-134 inhibits the activation of HSCs via directly targeting TAB1, and the restoration of miR-134 or targeting TAB1 is of clinical significance in the treatment of liver fibrosis.


2016 ◽  
Vol 310 (4) ◽  
pp. G262-G272 ◽  
Author(s):  
Yuchang Li ◽  
Ingrid Lua ◽  
Samuel W. French ◽  
Kinji Asahina

Mesothelial cells (MCs) form a single layer of the mesothelium and cover the liver surface. A previous study demonstrated that, upon liver injury, MCs migrate inward from the liver surface and give rise to hepatic stellate cells (HSCs) in biliary fibrosis induced by bile duct ligation (BDL) or myofibroblasts in CCl4-induced fibrosis. The present study analyzed the role of transforming growth factor-β (TGF-β) signaling in mesothelial-mesenchymal transition (MMT) and the fate of MCs during liver fibrosis and its regression. Deletion of TGF-β type II receptor ( Tgfbr2) gene in cultured MCs suppressed TGF-β-mediated myofibroblastic conversion. Conditional deletion of Tgfbr2 gene in MCs reduced the differentiation of MCs to HSCs and myofibroblasts in the BDL and CCl4 models, respectively, indicating that the direct TGF-β signaling in MCs is responsible to MMT. After BDL and CCl4 treatment, MC-derived HSCs and myofibroblasts were distributed near the liver surface and the thickness of collagen was increased in Glisson's capsule beneath the liver surface. Fluorescence-activated cell sorting analysis revealed that MC-derived HSCs and myofibroblasts store little vitamin A lipids and have fibrogenic phenotype in the fibrotic livers. MCs contributed to 1.4 and 2.0% of activated HSCs in the BDL and CCl4 models, respectively. During regression of CCl4-induced fibrosis, 20% of MC-derived myofibroblasts survived in the liver and deactivated to vitamin A-poor HSCs. Our data indicate that MCs participate in capsular fibrosis by supplying vitamin A-poor HSCs during a process of liver fibrosis and regression.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Ning Wang ◽  
Qihe Xu ◽  
Hor Yue Tan ◽  
Ming Hong ◽  
Sha Li ◽  
...  

Aim.To examine the effect of berberine (BBR) on liver fibrosis and its possible mechanisms through direct effects on hepatic stellate cells (HSC).Methods.The antifibrotic effect of BBR was determined in a rat model of bile duct ligation- (BDL-) induced liver fibrosis. Multiple cellular and molecular approaches were introduced to examine the effects of BBR on HSC.Results.BBR potently inhibited hepatic fibrosis induced by BDL in rats. It exhibited cytotoxicity to activated HSC at doses nontoxic to hepatocytes. High doses of BBR induced apoptosis of activated HSC, which was mediated by loss of mitochondrial membrane potential and Bcl-2/Bax imbalance. Low doses of BBR suppressed activation of HSC as evidenced by the inhibition ofα-smooth muscle actin (α-SMA) expression and cell motility. BBR did not affect Smad2/3 phosphorylation but significantly activated 5′ AMP-activated protein kinase (AMPK) signalling, which was responsible for the transcriptional inhibition by BBR of profibrogenic factorsα-SMA and collagen in HSC.Conclusion.BBR is a promising agent for treating liver fibrosis through multiple mechanisms, at least partially by directly targeting HSC and by inhibiting the AMPK pathway. Its value as an antifibrotic drug in patients with liver disease deserves further investigation.


1997 ◽  
Vol 272 (3) ◽  
pp. G589-G596 ◽  
Author(s):  
M. Ohata ◽  
M. Lin ◽  
M. Satre ◽  
H. Tsukamoto

Hepatic stellate cells (HSC) participate in liver fibrogenesis via myofibroblastic activation, the extent of which appears to correlate with the loss of cellular vitamin A. The present study has tested a hypothesis that HSC activation is associated with diminished retinoic acid (RA) signaling. Pure HSC were isolated from rats with cholestatic liver fibrosis induced by bile duct ligation (BDL) and sham-operated animals (Sham). Northern blot analysis of HSC RNA from BDL confirmed fibrogenic activation of the cells with enhanced mRNA levels for procollagen-alpha1(I) and transforming growth factor-beta1 (TGF-beta1). Competitive polymerase chain reaction analysis showed selective reductions in the mRNA levels of RA receptor (RAR)-beta and retinoid X receptor (RXR)-alpha to 20 and 17% of the Sham HSC. The mRNA level for cellular retinol binding protein I, a gene with RA responsive element (RARE), was also suppressed by 78% in BDL. The concentrations of all-trans-RA and 9-cis-RA were decreased in HSC from BDL. Nuclear extracts of these cells showed diminished binding activity to the RARE, whereas activity of AP-1, a transcription factor known to be antagonized by RAR and RXR, was enhanced. These results demonstrate diminished RA signaling in HSC from cholestatic liver fibrosis, which appeared to have resulted from RA deficiency and suppressed expression of RAR-beta and RXR-alpha. Furthermore, the reciprocal enhancement of AP-1 activity and coordinately increased expression of an AP-1 responsive gene, TGF-beta1, suggest a permissive role of the diminished RA signaling in promoting AP-1 activity and TGF-beta1 expression.


Author(s):  
Qi Yan ◽  
Linxin Pan ◽  
Shunli Qi ◽  
Fang Liu ◽  
Zhen Wang ◽  
...  

The therapeutic approach of liver fibrosis is still an unsolved clinical problem worldwide. Notably, the accumulation of extracellular matrix (ECM) in the liver is mediated by the production of cytokines and growth factors, such as transforming growth factor-β1 (TGF-β1) in hepatic stellate cells (HSCs). Ring finger protein 2 (RNF2) was identified as the catalytic subunit of polycomb repressive complex 1 (PRC1), mediating the monoubiquitination of histone H2A. In recent years, a growing amount of evidence suggests that RNF2 may play an important role in multiple pathological processes involved in cancer. Here, we explored the role of RNF2 in liver fibrogenesis and its potential mechanisms. The results showed that RNF2 was up-regulated in human fibrotic liver tissue. Knockdown of RNF2 led to a decreasing expression of collagen1 and α-smooth muscle actin (α-SMA) in LX-2 cells, which was upregulated by RNF2 overexpression. Moreover, RNF2 overexpression significantly promoted TGF-β1-induced LX-2 cell proliferation but decreased apoptosis. Furthermore, knockdown of RNF2 inhibited the activation of ERK/p38 signaling pathways induced by TGF-β1. These data suggested that RNF2 is an effective pro-fibrogenic factor for HSC activation via ERK/p38 signaling pathway. RNF2 inhibition might be a promising therapeutic target for liver fibrosis.


2009 ◽  
Vol 296 (6) ◽  
pp. G1248-G1257 ◽  
Author(s):  
Azuma Watanabe ◽  
Muhammad Adnan Sohail ◽  
Dawidson Assis Gomes ◽  
Ardeshir Hashmi ◽  
Jun Nagata ◽  
...  

The inflammasome is a cytoplasmic multiprotein complex that has recently been identified in immune cells as an important sensor of signals released by cellular injury and death. Analogous to immune cells, hepatic stellate cells (HSC) also respond to cellular injury and death. Our aim was to establish whether inflammasome components were present in HSC and could regulate HSC functionality. Monosodium urate (MSU) crystals (100 μg/ml) were used to experimentally induce inflammasome activation in LX-2 and primary mouse HSC. Twenty-four hours later primary mouse HSC were stained with α-smooth muscle actin and visualized by confocal microscopy, and TGF-β and collagen1 mRNA expression was quantified. LX-2 cells were further cultured with or without MSU crystals for 24 h in a transwell chemotaxis assay with PDGF as the chemoattractant. We also examined inhibition of calcium (Ca2+) signaling in LX-2 cells treated with or without MSU crystals using caged inositol 1,4,5-triphosphate (IP3). Finally, we confirmed an important role of the inflammasome in experimental liver fibrosis by the injection of carbon tetrachloride (CCl4) or thioacetamide (TAA) in wild-type mice and mice lacking components of the inflammasome. Components of the inflammasome are expressed in LX-2 cells and primary HSC. MSU crystals induced upregulation of TGF-β and collagen1 mRNA and actin reorganization in HSCs from wild-type mice but not mice lacking inflammasome components. MSU crystals inhibited the release of Ca2+ via IP3 in LX-2 cells and also inhibited PDGF-induced chemotaxis. Mice lacking the inflammasome-sensing and adaptor molecules, NLRP3 and apoptosis-associated speck-like protein containing CARD, had reduced CCl4 and TAA-induced liver fibrosis. We concluded that inflammasome components are present in HSC, can regulate a variety of HSC functions, and are required for the development of liver fibrosis.


2021 ◽  
pp. 002215542110536
Author(s):  
Ikuyo Inoue ◽  
Xian-Yang Qin ◽  
Takahiro Masaki ◽  
Yoshihiro Mezaki ◽  
Tomokazu Matsuura ◽  
...  

Transforming growth factor-β (TGF-β) activation is involved in various pathogeneses, such as fibrosis and malignancy. We previously showed that TGF-β was activated by serine protease plasma kallikrein-dependent digestion of latency-associated peptides (LAPs) and developed a method to detect LAP degradation products (LAP-DPs) in the liver and blood using specific monoclonal antibodies. Clinical studies have revealed that blood LAP-DPs are formed in the early stages of liver fibrosis. This study aimed to identify the cell source of LAP-DP formation during liver fibrosis. The N-terminals of LAP-DPs ending at residue Arg58 (R58) were stained in liver sections of a bile duct-ligated liver fibrosis model at 3 and 13 days. R58 LAP-DPs were detected in quiescent hepatic stellate cells at day 3 and in macrophages on day 13 after ligation of the bile duct. We then performed a detailed analysis of the axial localization of R58 signals in a single macrophage, visualized the cell membrane with the anti-CLEC4F antibody, and found R58 LAP-DPs surrounded by the membrane in phagocytosed debris that appeared to be dead cells. These findings suggest that in the early stages of liver fibrosis, TGF-β is activated on the membrane of stellate cells, and then the cells are phagocytosed after cell death: (J Histochem Cytochem XX:XXX–XXX, XXXX)


Author(s):  
Qiao You Lau ◽  
Fuad Gandhi Torizal ◽  
Marie Shinohara ◽  
Yasuyuki Sakai

During chronic liver injury, inflammation leads to the development of liver fibrosis— particularly due to the activation of hepatic stellate cells (HSCs). However, the involvement of inflammatory cytokines in HSC activation is unclear. Many existing in vitro liver models do not include these non-parenchymal cells (NPCs), and hence, do not represent the physiological relevance found in vivo. Herein, we demonstrated the hierarchical coculture of primary rat hepatocytes with NPCs such as the human-derived HSC line (LX-2) and the human-derived liver sinusoidal endothelial cell line (TMNK-1). The coculture tissue had higher albumin production and hepatic cytochrome P450 3A4 activity compared to the monoculture. We then further studied the effects of stimulation by both oxygen tension and key pro-fibrogenic cytokines, such as the transforming growth factor beta (TGF-β), on HSC activation. Gene expression analysis revealed that lower oxygen tension and TGF-β1 stimulation enhanced collagen type I, III, and IV, alpha-smooth muscle actin, platelet-derived growth factor, and matrix metallopeptidase expression from LX-2 cells in the hierarchical coculture after fibrogenesis induction. This hierarchical in vitro cocultured liver tissue could, therefore, provide an improved platform as a disease model for elucidating the interactions of various liver cell types and biochemical signals in liver fibrosis studies.


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