Hepatic alpha-smooth muscle actin expression in hepatitis C patients before and after interferon therapy

BACKGROUND/AIMS: The mechanism of hepatic fibrogenesis with chronic viral hepatitis is not well understood. Persistent activation of hepatic stellate cells is felt to play a role in the development of fibrogenesis and progression to cirrhosis. METHODOLOGY: We determined the expression of hepatic alpha-smooth muscle actin, a marker of hepatic stellate cell activation, in 29 patients with chronic hepatitis C and varying degrees of liver injury and fibrosis. In addition to a baseline evaluation, we assessed the effect of interferon therapy on alpha-smooth muscle actin expression in 11 patients, including 6 with a sustained response to therapy. Specimens were evaluated by light microscopy for grade of inflammation and stage of fibrosis. Expression of alpha-smooth muscle actin was assessed semiquantitatively by immunohistochemical staining. RESULTS: At baseline, all patients had alpha-smooth muscle actin expressed within the liver without an obvious correlation with the severity of liver injury. However, among sustained responders, a reduction in hepatic necroinflammatory activity was associated with a trend towards a decrease in alpha-smooth muscle actin expression. This however did not reach statistical significance. CONCLUSIONS: Hepatic alpha-smooth muscle actin expression, as a marker of hepatic stellate cell activation appears reversible and tends to correlate with necroinflammatory activity.     

Alpha-SMA expression in hepatic stellate cells and quantitative analysis of hepatic fibrosis in cirrhosis and in recurrent chronic hepatitis after liver transplantation

BACKGROUND: The alpha isotype of actin expressed by hepatic stellate cells reflects their activation to myofibroblast-like cell and has been directly related to experimental liver fibrogenesis, and indirectly to human fibrosis in chronic liver disease. AIMS: To evaluate the changes in distribution and percentage of alpha-smooth muscle actin-positive hepatic stellate cells and the correlation with the degree of the fibrosis in cirrhotic livers, as well as in patients with recurrent HCV chronic hepatitis after liver transplantation. METHODS: Human liver biopsies were divided in four groups: (1) normal livers obtained from cadaveric liver donors (n=35), (2) cirrhosis post-HBV hepatitis (n=11), (3) cirrhosis post-HCV hepatitis (n=10), and (4) post-transplant recurrent HCV chronic hepatitis (n=13). Samples were stained with anti-alpha-smooth muscle actin antibody by immunoperoxidase method and semi-quantitatively evaluated. Liver fibrosis was assessed from specimens stained with Masson's trichrome and quantified by computer image analysis. RESULTS: The percentage of alpha-smooth muscle actin-positive hepatic stellate cells was significantly higher in the HBV cirrhosis, HCV cirrhosis and post-transplant HCV recurrent hepatitis groups (36.1+/-15.2, 23.8+/-19.7 and 27.8+/-16.4%, respectively) compared to the liver donor group (2.9+/-4.0%). The alpha-smooth muscle actin-positive hepatic stellate cells to fibrous tissue ratio were significantly higher in the post-transplant recurrent HCV hepatitis group (2.36+/-1.12) compared to both the donor livers and the HCV cirrhosis groups (0.74+/-1.09 and 1.03+/-0.91, respectively). The alpha-smooth muscle actin-positive hepatic stellate cell percentage and fibrosis correlated positively in the post-transplant recurrent HCV hepatitis group and negatively in the HCV cirrhosis group. No difference in the immunohistochemical and morphometrical variables was found between the HCV cirrhosis and HBV cirrhosis groups. CONCLUSIONS: These results indirectly confirm that, in vivo, alpha-smooth muscle actin expression is a reliable marker of hepatic stellate cells activation which precedes fibrous tissue deposition even in the setting of recurrent HCV chronic hepatitis after liver transplantation, and it could be useful to identify the earliest stages of hepatic fibrosis and monitoring the efficacy of the therapy. In the presence of advanced cirrhosis other factors, rather than alpha-smooth muscle actin-positive hepatic stellate cells, may sustain fibrosis deposition.     

Rho/Rho kinase is a key enzyme system involved in the angiotensin II signaling pathway of liver fibrosis and steatosis

BACKGROUND AND AIM: The molecular mechanisms underlying the involvement of the renin-angiotensin system in hepatic fibrosis are unclear. Recently, it was reported that a Rho kinase inhibitor prevented fibrosis of various tissues and that the Rho/Rho kinase pathway was involved in the renin-angiotensin system of vascular smooth muscle cells. In this study, the involvement of the Rho/Rho kinase pathway on angiotensin II signaling in liver fibrogenesis and generation of steatosis was investigated. METHODS: Rats were fed a choline-deficient/L-amino acid-defined (CDAA) diet continuously and treated with a Rho kinase inhibitor, Y-27632, and an angiotensin II receptor blocker, TCV-116. Liver histology and hepatic stellate cell activation were analyzed. Free radical production was detected by 4-hydroxynonenal and 8-hydroxy-2'-deoxyguanosine immunostaining and the expression of tumor necrosis factor-alpha was examined. Isolated hepatic stellate cells were pretreated with a Rho kinase inhibitor, Y-27632, or an angiotensin II receptor blocker, CV-11974, and stimulated with angiotensin II, and mRNA expression of transforming growth factor-beta and alpha-smooth muscle actin was analyzed. RESULTS: Both the angiotensin II receptor blocker and the Rho kinase inhibitor improved fibrosis and steatosis of the liver in CDAA-fed rats. The increase in the number of hepatocytes positive for 4-hydroxynonenal and 8-hydroxy-2'-deoxyguanosine in CDAA-fed rats was significantly prevented by the angiotensin II receptor blocker and the Rho kinase inhibitor. The levels of tumor necrosis factor-alpha mRNA in the liver of CDAA-fed rats were significantly increased and this increase was significantly inhibited by treatment with the angiotensin II receptor blocker and the Rho kinase inhibitor. mRNA expression of transforming growth factor-beta and alpha-smooth muscle actin stimulated by angiotensin II was also significantly suppressed by these two drugs. CONCLUSION: These results suggest that the Rho/Rho kinase pathway is at least partly involved in the renin-angiotensin system and plays an important role in hepatic fibrosis and steatosis.     

Hepatic stellate cell activation occurs in nonalcoholic steatohepatitis

BACKGROUND/AIMS: Hepatic stellate cell activation has a major role in the pathogenesis of hepatic fibrosis, considered to constitute part of the healing response to a necroinflammatory stimulus. However, steatosis per se, has also been shown to induce this activation. This study evaluates if hepatic stellate cell activation is present, and how it correlates with steatosis, in nonalcoholic steatohepatitis, whose hallmark is steatosis. METHODOLOGY: Steatosis, hepatocyte damage, inflammation and fibrosis were graded from 0 to 3+, in liver biopsies from 15 well documented nonalcoholic steatohepatitis and 5 normal controls. Activated hepatic stellate cell activation were identified immunohistochemically using a monoclonal antibody raised against cytoplasmic alpha-smooth muscle actin, and semiquantitatively graded using a scoring method. RESULTS: Nonalcoholic steatohepatitis patients showed significantly greater numbers of alpha-smooth muscle actin-reactive hepatic stellate cell than controls: hepatic stellate cell index of 3.6 +/- 1.9 versus 1.5 +/- 0.5, P < 0.05. The distribution of alpha-smooth muscle actin-reactive hepatic stellate cell was higher in the perivenular areas, than in the intermediate zone and portal area, with no significant association between steatosis and alpha-smooth muscle actin-expressing hepatic stellate cell. However, a significant association was found between portal and lobular inflammation and hepatic stellate cell index, r = 0.72, P = 0.0005 and r = 0.75, P = 0.0002, respectively. CONCLUSIONS: This study demonstrates that hepatic stellate cell activation occurs in nonalcoholic steatohepatitis, clearly correlating with portal and lobular inflammation, but not with steatosis, suggesting that the mechanisms implicated in fibrosis in nonalcoholic steatohepatitis are probably related with inflammation.     

Liver fibrosis induced by hepatic overexpression of PDGF-B in transgenic mice

BACKGROUND/AIMS: In hepatic fibrogenesis, stellate cells are activated leading to production and deposition of extracellular matrix. To clarify the role of PDGF-B in liver fibrogenesis, we overexpressed PDGF-B in the liver of transgenic mice. METHODS: Transgenic mice for the conditional overexpression of PDGF-B in the liver under control of an albumin promoter were generated utilising the Cre/loxP system. Constitutive PDGF-B expression was achieved after breeding with mice expressing Cre-recombinase under actin promoter control. Tamoxifen inducible expression was achieved after breeding with mice expressing Cre under transthyretin receptor promoter control. Levels of fibrosis were assessed and the expression of regulators of matrix remodelling was measured. RESULTS: PDGF-B expression caused hepatic stellate cell and myofibroblast activation marked by alpha-smooth muscle actin and PDGFR-beta expression. Liver fibrosis was verified macroscopically, histologically and by collagen I mRNA quantification in 4-6 week-old animals. MMP-2, MMP-9 and TIMP-1 were upregulated whereas TGF-beta expression was unchanged. CONCLUSIONS: We identified PDGF-B as a proliferative and profibrogenic stimulus and potential inducer of stellate cell transdifferentiation in vivo. PDGF-B overexpression causes liver fibrosis without significantly upregulating TGF-beta1, suggesting a TGF-beta-independent mechanism. The established model provides a tool for testing anti-PDGF-B therapeutic strategies in liver fibrosis in vivo.     

肝星状细胞SSeCKS的表达及其在肝纤维化中的作用

目的 了解src抑制的蛋白激酶C底物(SSeCKS)在肝星状细胞(HSC)活化中的变化和作用.方法 (1)分离正常大鼠的HSC,以实时定量PCR检测其在体外培养过程中SSeCKS mRNA的表达变化,以蛋白质印迹法和细胞免疫荧光法检测HSC中SSeCKS蛋白的表达变化.(2)制作肝纤维化的大鼠模型,以免疫荧光法检测肝组织内SSeCKS和α-平滑肌肌动蛋白(α-SMA)的表达变化及定位.结果 初分离的HSC表达低水平的SSeCKS mRNA,经培养活化后SSeCKS的表达增强.在纤维化肝组织中,SSeCKS阳性细胞增多,阳性细胞多分布于肝窦周围,与α-SMA阳性细胞的分布一致.结论 在体外活化过程中HSC中SSeCKS表达增强.SSeCKS可能参与HSC在肝脏炎症和纤维化中的作用.     

Expression of the Na+/Ca2+ exchanger emerges in hepatic stellate cells after activation in association with liver fibrosis

Activation of hepatic stellate (Ito) cells is a final common pathway of liver fibrosis. The findings presented in this paper indicate that expression of Na⁺/Ca²⁺ exchanger (NCX) emerges in rat hepatic stellate cells after activation in vitro during primary culture or in vivo in response to intoxication with CCl₄. NCX mRNA became detectable by Northern blot analysis in cultured stellate cells on day 3, as was α-smooth muscle actin, an indicator not only of smooth muscle differentiation but also of stellate cell activation. Western blot analysis showed expression of the exchanger protein in the activated stellate cells. Functional expression of the exchanger, monitored by Ni²⁺-sensitive, verapamil-insensitive intracellular free Ca²⁺ increases in response to reduction of extracellular Na⁺ concentration, became sizable by using Fura-2 in stellate cells by 7 days in culture. Furthermore, increased expression of the exchanger mRNA was found predominantly in stellate cells freshly isolated from the CCl₄ model rat of hepatic fibrosis. Thus, it is concluded that NCX expression is closely associated with activation of hepatic stellate cells in vitro and in vivo. Because, even at the whole liver level, increased expression of NCX mRNA became observable after induction of liver fibrosis, it is suggested that NCX expression serves a useful diagnostic marker of liver fibrosis or cirrhosis.     

Stress-activated protein kinases in the activation of rat hepatic stellate cells in culture

BACKGROUND/AIMS: The signal cascades involved in the activation of hepatic stellate cells (HSC) are largely unknown. Factors initiating activation include tumour necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, endothelin, and oxidative stress. In other cell types some of these have been reported to stimulate p38 mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK). We have therefore investigated the role of these kinases in HSC activation. METHODS: HSC were isolated from male Wistar rats. Quiescent experiments were performed on day 2 HSC and transformed experiments on day 15 passage 1 HSC. Kinase activities were determined by immunoprecipitation and phosphorylation of specific substrate proteins and alpha-smooth muscle actin (SMA) expression by immunoblotting. RESULTS: The constitutive activity of p38 MAP kinase was higher in transformed versus quiescent cells. In quiescent cells TNFalpha stimulated p38 MAP kinase and JNK activities 12- and 4-fold respectively and this was halved by 2-mercaptoethanol, an indirect antioxidant. Endothelin-1 activated both kinases in quiescent cells via the endothelin-B receptor, while TGFbeta had no effect. Both 2-mercaptoethanol and a p38 inhibitor (SB202190) inhibited alpha-SMA expression by day 5 cells. CONCLUSIONS: The activation of p38 MAP kinase and JNK by TNFalpha and endothelin, together with the inhibition of this activation by 2-mercaptoethanol, provides indirect evidence supporting their role in HSC transformation. Direct evidence for a role for p38 MAP kinase is provided by the observations that its constitutive activity is higher in transformed versus quiescent cells and that its inhibitor reduces HSC activation in culture as assessed by alpha-SMA expression.     

Immune stimulation of hepatic fibrogenesis by CD8 cells and attenuation by transgenic interleukin-10 from hepatocytes

BACKGROUNDS & AIMS: Immunomodulatory cytokines, including interleukin-10 (IL-10), may mediate hepatic fibrosis. METHODS: We generated transgenic (TG) mice with hepatocyte expression of rat IL-10 (rIL-10) to assess its impact on lymphocyte subsets and activation of hepatic stellate cells following liver injury from carbon tetrachloride (CCl 4 ) or thioacetamide (TAA). RESULTS: Fibrosis was reduced in the TG animals in both models, which was not explained solely by differences in liver injury. By fluorescence-activated cell sorter (FACS), there were less CD4+ T cells in naive TG mice, and, following fibrosis induction, CD4+ T cells decreased only in wild-type (WT) mice, whereas increases in CD8+ T cells seen in WT animals were significantly attenuated in TG mice. Subtotal irradiation diminished fibrosis equally in both WT and TG groups, suggesting that rIL-10's antifibrotic effect was lymphocyte mediated. To assess the role of lymphocytes on stellate cell activation, either whole splenic lymphocytes, CD4+, or CD8+ T-cell subsets from WT animals with CCl 4 fibrosis were adoptively transferred to severe combined immunodeficiency (SCID) recipients, which led to stellate cell activation and fibrogenic stimulation as assessed by expression of transforming growth factor (TGF)-beta1 and collagen I messenger RNA (mRNA) and by immunoblot of alpha-smooth muscle actin. Moreover, serum aminotransferase levels and stellate cell activation mRNA were significantly higher among the CD8+ T-cell recipients. CONCLUSIONS: Transgenic expression of rIL-10 in liver leads to reduced fibrosis and alterations in liver lymphocyte subsets both in untreated liver and following fibrosis induction. In this model, fibrosis may be a CD8+ T-cell-mediated disease that is attenuated by rIL-10.     

The epidermal growth factor receptor ligand amphiregulin participates in the development of mouse liver fibrosis

The hepatic wound-healing response to chronic noxious stimuli may lead to liver fibrosis, a condition characterized by excessive deposition of extracellular matrix. Fibrogenic cells, including hepatic stellate cells and myofibroblasts, are activated in response to a variety of cytokines, growth factors, and inflammatory mediators. The involvement of members of the epidermal growth factor family in this process has been suggested. Amphiregulin (AR) is an epidermal growth factor receptor (EGFR) ligand specifically induced upon liver injury. Here, we have addressed the in vivo role of AR in experimental liver fibrosis. To this end, liver fibrosis was induced in AR+/+ and AR-/- mice by chronic CCl(4) administration. Histological and molecular markers of hepatic fibrogenesis were measured. Additionally, the response of cultured human and mouse liver fibrogenic cells to AR was evaluated. We observed that AR was expressed in isolated Kupffer cells and liver fibrogenic cells in response to inflamatory stimuli and platelet-derived growth factor, respectively. We demonstrate that the expression of alpha-smooth muscle actin and collagen deposition were markedly reduced in AR-/- mice compared to AR+/+ animals. AR-/- mice also showed reduced expression of tissue inhibitor of metalloproteinases-1 and connective tissue growth factor, two genes that responded to AR treatment in cultured fibrogenic cells. AR also stimulated cell proliferation and exerted a potent antiapoptotic effect on isolated fibrogenic cells. CONCLUSION: These results indicate that among the different EGFR ligands, AR plays a specific role in liver fibrosis. AR may contribute to the expression of fibrogenic mediators, as well as to the growth and survival of fibrogenic cells. Additionally, our data lend further support to the role of the EGFR system in hepatic fibrogenesis.     

Transforming growth factor-beta and substrate stiffness regulate portal fibroblast activation in culture

Myofibroblasts derived from portal fibroblasts are important fibrogenic cells in the early stages of biliary fibrosis. In contrast to hepatic stellate cells, portal fibroblasts have not been well studied in vitro, and little is known about their myofibroblastic differentiation. In this article we report the isolation and characterization of rat portal fibroblasts in culture. We demonstrate that primary portal fibroblasts undergo differentiation to alpha-smooth muscle actin-expressing myofibroblasts over 10-14 days. Marker analysis comparing portal fibroblasts to hepatic stellate cells demonstrated that these are distinct populations and that staining with elastin and desmin can differentiate between them. Portal fibroblasts expressed elastin at all stages in culture but never expressed desmin, whereas hepatic stellate cells consistently expressed desmin but never elastin. Immunostaining of rat liver tissue confirmed these results in vivo. Characterization of portal fibroblast differentiation in culture demonstrated that these cells required transforming growth factor-beta (TGF-beta): cells remained quiescent in the presence of a TGF-beta receptor kinase inhibitor, whereas exogenous TGF-beta1 enhanced portal fibroblast alpha-smooth muscle actin expression and stress fiber formation. In contrast, platelet-derived growth factor inhibited myofibroblastic differentiation. Portal fibroblasts were also dependent on mechanical tension for myofibroblastic differentiation, and cells cultured on polyacrylamide supports of variable stiffness demonstrated an increasingly myofibroblastic phenotype as stiffness increased. CONCLUSION: Portal fibroblasts are morphologically and functionally distinct from hepatic stellate cells. Portal fibroblast myofibroblastic differentiation can be modeled in culture and requires both TGF-beta and mechanical tension.     

Quantitative analysis of liver fibrosis and stellate cell changes in patients with chronic hepatitis C after interferon therapy

OBJECTIVE: The proliferation and differentiation of stellate (Ito, or fat-storing) cells into myofibroblast-like cells is responsible for the development of liver fibrosis. Using computer image analysis, we evaluated the changes of alpha smooth muscle actin-positive stellate cells and liver fibrosis after interferon-alpha or -beta (IFN-alpha, beta) therapy in patients with chronic hepatitis C. METHODS: Patients with chronic hepatitis C were treated with IFN-alpha or -beta and were divided into three groups on the basis of clinical criteria; a complete responder group (CR, 18 of 51), a partial responder group (PR, 17 to 51), and a nonresponder group (NR, 16 of 51). Liver fibrosis was assessed from specimens stained with Sirius red and was quantitated by computer image analysis. We also evaluated alpha-smooth muscle actin expression in the liver before and after IFN therapy by a semiquantitative scoring method (the alpha-smooth muscle actin index). RESULTS: Before IFN therapy, a large number of stellate cells expressing a-smooth muscle actin were present in the liver biopsy specimens. There was a significant correlation (r = 0.699, p < 0.05) between the change in the percent area of fibrosis and the alpha-smooth muscle actin index before and after IFN therapy in all groups. The complete responder group also showed a significant reduction of a-smooth muscle actin-expressing cells that was correlated with the reduction of serum ALT (r = 0.686, p < 0.05). CONCLUSION: These results suggest a-smooth muscle actin-expressing cells are responsible for liver fibrosis, and the elimination of factors stimulating matrix synthesis (e.g., hepatitis virus) may decrease liver fibrosis.     

RhoA在肝纤维化中的作用机制

肝纤维化发生的关键在于肝星状细胞（HSC）转化为成纤维母细胞及活化后细胞外基质（ECM）的异常表达。回顾了Rho/ROCK信号通路在HSC的激活中的重要作用。总结了RhoA,作为Rho/ROCK信号通路上小G蛋白家庭成员之一,且作为一种重要的调节肌动蛋白细胞骨架和细胞形态异质性的细胞因子,参与肝纤维化的进程。指出RhoA在肝脏纤维化发生发展过程中起着重要的调控作用,归纳了RhoA通过调节肌动蛋白应力纤维的装配,并通过级联放大效应影响细胞基质的合成和收缩,最终影响肝纤维化的进展。就RhoA在肝纤维化过程中的机制以及RhoA作为潜在的治疗靶点作一综述。     

Suppressive effects of estradiol on dimethylnitrosamine-induced fibrosis of the liver in rats

As a model for the analysis of the fibrosuppressive role of estradiol, hepatic fibrosis was induced in male and female rats by the administration of a single dose of dimethylnitrosamine (DMN). The fibrotic response of the male liver after DMN treatment was significantly stronger than that of the female liver. In the male DMN model, estradiol reduced hepatic mRNA for type I and III procollagens and the tissue inhibitor of metalloproteinase-1 (TIMP-1), as well as deposition of type I and III collagen protein total hepatic collagen and malondialdehyde (MDA), a product of lipid peroxidation. Concomitant administration of a neutralizing antibody against rat estradiol enhanced fibrogenesis, as judged by the same parameters. Ovariectomy in the female model had a fibrogenic effect, inducing the hepatic expression of both types of procollagen and TIMP-1; in addition, the number of alpha-smooth muscle actin (alpha-SMA)-positive cells in the liver increased; estradiol replacement was fibrosuppressive in the castrated-female model. In rat hepatic stellate cells incubated in primary culture with estradiol, cell number, type I collagen production, and alpha-SMA expression were all reduced. These findings suggest that estradiol suppressed the induction of hepatic fibrosis, and may in part underlie the more rapid progression in males of hepatic fibrosis and its complications.     

A selective ROCK inhibitor, Y27632, prevents dimethylnitrosamine-induced hepatic fibrosis in rats

BACKGROUND: p160ROCK is a direct Rho target which mediates Rho-induced assembly of focal adhesions and stress fibers. We previously reported that Rho signaling pathways are involved in the activation of hepatic stellate cells (HSC) in vitro. The aim of the present study was to test the hypothesis that an inhibitor specific for p160ROCK (Y27632) could prevent experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. METHODS: Y27632 was given orally at 30 mg/kg daily for 4 weeks after the first injection of DMN. The degree of fibrosis was evaluated by image analysis and also by measurements of collagen and hydroxyproline content in the liver. The expression of alpha-smooth muscle actin (alpha-SMA) in the liver and in the primary cultured HSC was also evaluated. Semi-quantitative RT-PCR was performed to evaluate the expression of type I collagen mRNA in the liver. RESULTS: Y27632 treatment significantly decreased the occurrence of DMN-induced hepatic fibrosis and reduced the collagen and hydroxyproline content and alpha-SMA expression in the liver. The expression of alpha-SMA in HSC was also suppressed in vitro. CONCLUSIONS: These findings indicate that inhibitors of the Rho-ROCK pathway might be useful therapeutically in hepatic fibrosis.     

肝星状细胞在逆转肝纤维化中的作用

肝纤维化是一种能够导致门静脉高压、肝硬化、肝衰竭的严重疾病。已经发现肝星状细胞的活化是引起肝纤维化的中心环节,因此抑制肝星状细胞的活化、加速肝星状细胞的清除有望逆转肝纤维化。本文将对活化的肝星状细胞的凋亡、衰老以及清除的研究进展作综述,阐明肝星状细胞在肝纤维化过程中所起的作用及相关机制。     

锌α2糖蛋白抑制肝星状细胞活化和增殖的体外研究

目的探讨锌α2糖蛋白(AZGP1)在肝星状细胞活化和肝纤维化发生和发展中的作用机制。方法采用转化生长因子-β1刺激诱导人肝星状细胞株LX2活化和构建四氯化碳小鼠肝纤维化模型,观察细胞和肝组织中AZGP1的表达情况。应用质粒转染法过表达和抑制表达AZGP1后,分别检测LX2细胞的活化、增殖和凋亡功能及相关因子的改变。多组间比较采用单因素方差分析。结果免疫荧光染色结果显示在活化的LX2细胞中,AZGP1蛋白减少而α-平滑肌肌动蛋白增多,二者呈负相关。AZGP1基因和蛋白在活化的LX2细胞和四氯化碳肝纤维化小鼠的肝组织内显著低表达。过表达AZGP1后,LX2细胞中Ⅰ型胶原、基质金属蛋白酶-2和α-平滑肌肌动蛋白基因和蛋白明显下调;细胞荧光显示过表达AZGP1的细胞活化和α-平滑肌肌动蛋白减少。此外,过表达AZGP1后,LX2细胞的增殖活性和G1/S-特异性周期蛋白D1蛋白显著降低;细胞周期实验显示过表达AZGP1的细胞停滞在G0/G1期比例显著增多、而S期比例显著减少。AZGP1对LX2细胞凋亡无明显影响。结论AZGP1可通过抑制肝星状细胞活化和增殖而逆转肝纤维化;过表达AZGP1有望成为肝纤维化治疗的新靶点。