Ginsenoside Rb1 induces hepatic stellate cell ferroptosis to alleviate liver fibrosis via the BECN1/SLC7A11 axis

Liver fibrosis is primarily driven by the activation of hepatic stellate cells(HSCs),a process associated with ferroptosis.Ginsenoside Rb1(GRb1),a major active component extracted from Panax ginseng,inhibits HSC activation.However,the potential role of GRb1 in mediating HSC ferroptosis remains unclear.This study examined the effect of GRb1 on liver fibrosis both in vivo and in vitro,using CCl4-induced liver fibrosis mouse model and primary HSCs,LX-2 cells.The findings revealed that GRb1 effectively inactivated HSCs in vitro,reducing alpha-smooth muscle actin(a-SMA)and type I collagen(Col1A1)levels.Moreover,GRb1 significantly alleviated CCl4-induced liver fibrosis in vivo.From a mechanistic standpoint,the ferroptosis pathway appeared to be central to the antifibrotic effects of GRb1.Specifically,GRb1 promoted HSC ferroptosis both in vivo and in vitro,characterized by increased glutathione depletion,malondialdehyde production,iron overload,and accumulation of reactive oxygen species(ROS).Intriguingly,GRb1 increased Beclin 1(BECN1)levels and decreased the System Xc-key subunit SLC7A11.Further experiments showed that BECN1 silencing inhibited GRb1-induced effects on HSC ferroptosis and mitigated the reduction of SLC7A11 caused by GRb1.Moreover,BECN1 could directly interact with SLC7A11,initiating HSC ferroptosis.In conclusion,the suppression of BECN1 counteracted the effects of GRb1 on HSC inactivation both in vivo and in vitro.Overall,this study highlights the novel role of GRb1 in inducing HSC ferroptosis and promoting HSC inactivation,at least partly through its modulation of BECN1 and SLC7A11.

Taurine attenuates activation of hepatic stellate cells by inhibiting autophagy and inducing ferroptosis

BACKGROUND Liver fibrosis is a compensatory response during the tissue repair process in chronic liver injury,and finally leads to liver cirrhosis or even hepatocellular carcinoma.The pathogenesis of hepatic fibrosis is associated with the progressive accumulation of activated hepatic stellate cells(HSCs),which can transdiffer-entiate into myofibroblasts to produce an excess of the extracellular matrix(ECM).Myofibroblasts are the main source of the excessive ECM responsible for hepatic fibrosis.Therefore,activated hepatic stellate cells(aHSCs),the principal ECM producing cells in the injured liver,are a promising therapeutic target for the treatment of hepatic fibrosis.AIM To explore the effect of taurine on aHSC proliferation and the mechanisms involved.METHODS Human HSCs(LX-2)were randomly divided into five groups:Normal control group,platelet-derived growth factor-BB(PDGF-BB)(20 ng/mL)treated group,mmol/L,respectively)with PDGF-BB(20 ng/mL)treated group.Cell Counting Kit-8 method was performed to evaluate the effect of taurine on the viability of aHSCs.Enzyme-linked immunosorbent assay was used to estimate the effect of taurine on the levels of reactive oxygen species(ROS),malondialdehyde,glutathione,and iron concen-tration.Transmission electron microscopy was applied to observe the effect of taurine on the autophagosomes and ferroptosis features in aHSCs.Quantitative real-time polymerase chain reaction and Western blot analysis were performed to detect the effect of taurine on the expression ofα-SMA,Collagen I,Fibronectin 1,LC3B,ATG5,Beclin 1,PTGS2,SLC7A11,and p62.RESULTS Taurine promoted the death of aHSCs and reduced the deposition of the ECM.Treatment with taurine could alleviate autophagy in HSCs to inhibit their activation,by decreasing autophagosome formation,downregulating LC3B and Beclin 1 protein expression,and upregulating p62 protein expression.Meanwhile,treatment with taurine triggered ferroptosis and ferritinophagy to eliminate aHSCs characterized by iron overload,lipid ROS accumu-lation,glutathione depletion,and lipid peroxidation.Furthermore,bioinformatics analysis demonstrated that taurine had a direct targeting effect on nuclear receptor coactivator 4,exhibiting the best average binding affinity of-20.99 kcal/mol.CONCLUSION Taurine exerts therapeutic effects on liver fibrosis via mechanisms that involve inhibition of autophagy and trigger of ferroptosis and ferritinophagy in HSCs to eliminate aHSCs.

Perilipin 5 regulates hepatic stellate cell activation and high-fat diet-induced non-alcoholic fatty liver disease

Background:Nonalcoholic fatty liver disease(NAFLD)is one of the most common chronic liver diseases globally.Hepatic stellate cells(HSCs)are the major effector cells of liver fibrosis.HSCs contain abundant lipid droplets(LDs)in their cytoplasm during quiescence.Perilipin 5(PLIN 5)is a LD surface-associated protein that plays a crucial role in lipid homeostasis.However,little is known about the role of PLIN 5 in HSC activation.Methods:PLIN 5 was overexpressed in HSCs of Sprague–Dawley rats by lentivirus transfection.At the same time,PLIN 5 gene knockout mice were constructed and fed with a high-fat diet(HFD)for 20 weeks to study the role of PLIN 5 in NAFLD.The corresponding reagent kits were used to measure TG,GSH,Caspase 3 activity,ATP level,and mitochondrial DNA copy number.Metabolomic analysis of mice liver tissue metabolism was performed based on UPLC-MS/MS.AMPK,mitochondrial function,cell proliferation,and apoptosis-related genes and proteins were detected by western blotting and qPCR.Results:Overexpression of PLIN 5 in activated HSCs led to a decrease in ATP levels in mitochondria,inhibition of cell proliferation,and a significant increase in cell apoptosis through AMPK activation.In addition,compared with the HFD-fed C57BL/6J mice,PLIN 5 knockout mice fed with HFD showed reduced liver fat deposition,decreased LD abundance and size,and reduced liver fibrosis.Conclusion:These findings highlight the unique regulatory role of PLIN 5 in HSCs and the role of PLIN 5 in the fibrosis process of NAFLD.

KLF4 Inhibits the Activation of Human Hepatic Stellate Cell In Vitro

Objective Hepatic stellate cells(HSCs)play a crucial role in liver fibrosis.Early-stage liver fibrosis is reversible and intimately associated with the state of HSCs.Kruppel-like factor 4(KLF4)plays a pivotal role in a wide array of physiological and pathological processes.This study aimed to investigate the effect of KLF4 on the proliferation,apoptosis and phenotype of quiescent HSCs Methods We designed a KLF4 lentiviral vector and a KLF4 siRNA lentiviral vector,to upregulate and silence KLF4 expression in human HSC LX-2 cells via transfection.Cell proliferation was assessed using the CCK-8 assay.Flow cytometry was used to detect the cell cycle distribution and apoptosis rate.Western blotting was used to determine the levels of some quiescence and activation markers of HSCs Results Overexpression of KLF4 significantly increased the levels of E-cadherin and ZO-1,which are quiescent HSC markers,while significantly decreased the levels of N-cadherin and a-SMA,known activated HSC markers.In contrast,cell proliferation and apoptosis rates were elevated in LX-2 cells in which KLF4 expression was silenced Conclusion KLF4 inhibits the proliferation and activation of human LX-2 HSCs.It might be a key regulatory protein in the maintenance of HSC quiescence and may serve as a target for the inhibition of hepatic fibrosis.

HepG2.2.15-derived exosomes facilitate the activation and fibrosis of hepatic stellate cells

BACKGROUND The role of exosomes derived from HepG2.2.15 cells,which express hepatitis B virus(HBV)-related proteins,in triggering the activation of LX2 liver stellate cells and promoting liver fibrosis and cell proliferation remains elusive.The focus was on comprehending the relationship and influence of differentially expressed microRNAs(DE-miRNAs)within these exosomes.AIM To elucidate the effect of exosomes derived from HepG2.2.15 cells on the activation of hepatic stellate cell(HSC)LX2 and the progression of liver fibrosis.METHODS Exosomes from HepG2.2.15 cells,which express HBV-related proteins,were isolated from parental HepG2 and WRL68 cells.Western blotting was used to confirm the presence of the exosomal marker protein CD9.The activation of HSCs was assessed using oil red staining,whereas DiI staining facilitated the observation of exosomal uptake by LX2 cells.Additionally,we evaluated LX2 cell proliferation and fibrosis marker expression using 5-ethynyl-2′-deoxyuracil staining and western blotting,respectively.DE-miRNAs were analyzed using DESeq2.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathways were used to annotate the target genes of DE-miRNAs.RESULTS Exosomes from HepG2.2.15 cells were found to induced activation and enhanced proliferation and fibrosis in LX2 cells.A total of 27 miRNAs were differentially expressed in exosomes from HepG2.2.15 cells.GO analysis indicated that these DE-miRNA target genes were associated with cell differentiation,intracellular signal transduction,negative regulation of apoptosis,extracellular exosomes,and RNA binding.KEGG pathway analysis highlighted ubiquitin-mediated proteolysis,the MAPK signaling pathway,viral carcinogenesis,and the toll-like receptor signaling pathway,among others,as enriched in these targets.CONCLUSION These findings suggest that exosomes from HepG2.2.15 cells play a substantial role in the activation,proliferation,and fibrosis of LX2 cells and that DE-miRNAs within these exosomes contribute to the underlying mechanisms.

Linking fatty liver diseases to hepatocellular carcinoma by hepatic stellate cells

Hepatic stellate cells(HSCs),a distinct category of non-parenchymal cells in the liver,are critical for liver homeostasis.In healthy livers,HSCs remain non-proliferative and quiescent.However,under conditions of acute or chronic liver damage,HSCs are activated and participate in the progression and regulation of liver diseases such as liver fibrosis,cirrhosis,and liver cancer.Fatty liver diseases(FLD),including nonalcoholic(NAFLD)and alcoholrelated(ALD),are common chronic inflammatory conditions of the liver.These diseases,often resulting from multiple metabolic disorders,can progress through a sequence of inflammation,fibrosis,and ultimately,cancer.In this review,we focused on the activation and regulatory mechanism of HSCs in the context of FLD.We summarized the molecular pathways of activated HSCs(aHSCs)in mediating FLD and their role in promoting liver tumor development from the perspectives of cell proliferation,invasion,metastasis,angiogenesis,immunosuppression,and chemo-resistance.We aimed to offer an in-depth discussion on the reciprocal regulatory interactions between FLD and HSC activation,providing new insights for researchers in this field.

The Role of IκBα in TNF-α-induced Apoptosis in Hepatic Stellate Cell Line HSC-T6

To investigate the role of NF-κB in TNF-α induced apoptosis in HSC-T6, a mutant IκBα was transfected into HSC-T6 cells by lipofectin transfection technique and its transient effect was examined 48 h after the transfection. The activation of NF-κB was detected by immune fluorescence cytochemistry and Western blotting with anti-p65 antibody. The apoptosis and the rate of inhibition by TNF-α in both transfected and untransfected HSC-T6 cells were measured respectively by FAC-Scan side scatter analysis and MTF methods. Our results showed that TNF-α could activate NF-κB in untransfected cells but not in transfected HSC-T6 cells. The percentage of apoptosis in transfected cells were significantly higher than that in the untransfected ones （P〈0.01） and it was also true of the inhibition rate （P〈0.01）. It is concluded that the resistance of HSC-T6 towards apoptosis induced by TNF-α can be mediated by NF-κB activation. The inhibition of NF-κB activation by mutant IκBα can attenuate the resistance of HSC-T6 cells and increase its sensitivity to TNF-α.

Liver fibrosis and hepatic stellate cells: Etiology, pathological hallmarks and therapeutic targets

Liver fibrosis is a reversible wound-healing process aimed at maintaining organ integrity, and presents as the critical pre-stage of liver cirrhosis, which will eventually progress to hepatocellular carcinoma in the absence of liver transplantation. Fibrosis generally results from chronic hepatic injury caused by various factors, mainly viral infection, schistosomiasis, and alcoholism; however, the exact pathological mechanisms are still unknown. Although numerous drugs have been shown to have antifibrotic activity in vitro and in animal models, none of these drugs have been shown to be efficacious in the clinic. Importantly, hepatic stellate cells(HSCs) play a key role in the initiation, progression, and regression of liver fibrosis by secreting fibrogenic factors that encourage portal fibrocytes, fibroblasts, and bone marrow-derived myofibroblasts to produce collagen and thereby propagate fibrosis. These cells are subject to intricate cross-talk with adjacent cells, resulting in scarring and subsequent liver damage. Thus, an understanding of the molecular mechanisms of liver fibrosis and their relationships with HSCs is essential for the discovery of new therapeutic targets. This comprehensive review outlines the role of HSCs in liver fibrosis and details novel strategies to suppress HSC activity, thereby providing new insights into potential treatments for liver fibrosis.

Hepatic fibrosis： It is time to go with hepatic stellate cell-specifictherapeutic targets

Hepatic fibrosis is a pathological lesion, characterized by the progressive accumulation of extracellularmatrix （ECM） in the perisinusoidal space and it is a major problem in chronic liver diseases. Phenotypicactivation of hepatic stellate cells （HSC） plays a central role in the progression of hepatic fibrosis. Retardation of proliferation and clearance of activated HSCs from the injured liver is an appropriate therapeuticstrategy for the resolution and treatment of hepatic fibrosis. Clearance of activated HSCs from the injuredliver by autophagy inhibitors, proapoptotic agents and senescence inducers with the high affinity towardthe activated HSCs may be the novel therapeutic strategy for the treatment of hepatic fibrosis in the nearfuture.

Hes1,an important gene for activation of hepatic stellate cells,is regulated by Notch1 and TGF-β/BMP signaling

AIM:To determine the role of Notch1 and Hes1 in regulating the activation of hepatic stellate cells(HSCs) and whether Hes1 is regulated by transforming growth factor(TGF)/bone morphogenetic protein(BMP) signaling.METHODS:Immunofluorescence staining was used to detect the expression of desmin,glial fibrillary acidic protein and the myofibroblastic marker α-smooth muscle actin(α-SMA) after freshly isolated,normal rat HSCs had been activated in culture for different numbers of days(0,1,3,7 and 10 d).The expression of α-SMA,collagen1α2(COL1α2),Notch receptors(Notch1-4),and the Notch target genes Hes1 and Hey1 were analyzed by reverse transcriptase-polymerase chain reaction.Luciferase reporter assays and Western blot were used to study the regulation of α-SMA,COL1α1,COL1α2 and Hes1 by NICD1,Hes1,CA-ALK3,and CA-ALK5 in HSC-T6 cells.Moreover,the effects of inhibiting Hes1 function in HSC-T6 cells using a Hes1 decoy were also investigated.RESULTS:The expression of Notch1 and Hes1 m RNAs was significantly down-regulated during the culture of freshly isolated HSCs.In HSC-T6 cells,Notch1 inhibited the promoter activities of α-SMA,COL1α1 and COL1α2.On the other hand,Hes1 enhanced the promoter activities of α-SMA and COL1α2,and this effect could be blocked by inhibiting Hes1 function with a Hes1 decoy.Furthermore,co-transfection of pc DNA3-CAALK3(BMP signaling activin receptor-like kinase 3) and pc DNA3.1-NICD1 further increased the expression of Hes1 compared with transfection of either vector alone in HSC-T6 cells,while pc DNA3-CA-ALK5(TGF-β signaling activin receptor-like kinase 5) reduced the effect of NICD1 on Hes1 expression.CONCLUSION:Selective interruption of Hes1 or maintenance of Hes1 at a reasonable level decreases the promoter activities of α-SMA and COL1α2,and these conditions may provide an anti-fibrotic strategy against hepatic fibrosis.

Effects of retinoic acid on proliferation,phenotype and expression of cyclin-dependent kinase inhibitors in TGF-β1-stimulated rat hepatic stellate cells

AIM To study the molecular mechanisms ofretinoic acid(RA)on proliferation andexpression of cyclin-dependent kinase inhibitors(CKI),i.e.p16,p21 and p27 in cultured rathepatic stellate cells(HSC)stimulated withtransforming growth factor beta 1(TGF-β1).METHODS HSC were isolated from healthy ratlivers and cultured.After stimulated with1 mg/L TGF-β1,subcultured HSC were treatedwith or without 1 nmol/L RA.MTT assay,immunocytochemistry(ICC)for p16,p21,p27and α-smooth muscle actin(α-SMA)protein,insitu hybridization(ISH)for retinoic acidreceptor beta 2(RAR-β2)and p16,p21 and p27mRNA and quantitative image analysis(partially)were performed.RESULTS RA inhibited HSC proliferation(41.50%,P【0.05),decreased the protein levelof α-SMA(55.09%,P【0.05),and induced HSCto express RAR-β2 mRNA.In addition,RAincreased the protein level of p16(218.75%,P【0.05)and induced p21 protein expression;meanwhile,p27 was undetectable by ICC in bothcontrol and RA-treated HSC.However,RA hadno influence on the mRNA levels of p16,p21 orp27 as determined by ISH.CONCLISION Up-regulation of p16 and p21 on post-transcriptional level may contribule, in part to RA inhibition of TGF-β1-initiated rat HSC activation in vitro.

Effect of lipid on proliferation and activation of rat hepatic stellate cells(Ⅰ)

AIM To study the effect of lipid (triglyceride and very low density lipoprotein, VLDL) on proliferation and activation of rat hepatic stellate cells (HSC). METHODS HSC were isolated and cultured from liver of Wistar rats by in situ perfusion with pronase and collagenase and density gradient centrifugation with Nycodenz. HSC proliferation was examined with MTT colorimetric assay. RESULT Triglyceride of 12.5mg/L had a promoting effect on proliferation of HSC ( P <0 05), 25, 50, 100 and 200mg/L had no effects ( P >0 05), but 400mg/L had an inhibiting effect ( P <0 01). VLDL of 6 25 and 12 5mg/L had no effect on proliferation of HSC ( P >0 05), but increased concentration of VLDL could promote the HSC proliferation ( P <0 05). CONCLUSION Lipid had an effect on proliferation of HSC. Triglyceride and VLDL may promote HSC proliferation and may be associated with fatty liver and hepatic fibrogenesis.

Bone morphogenetic protein-7 represses hepatic stellate cell activation and liver fibrosis via regulation of TGF-β/Smad signaling pathway

BACKGROUND Liver fibrosis is a refractory disease whose persistence can eventually induce cirrhosis or even liver cancer.Early liver fibrosis is reversible by intervention.As a member of the transforming growth factor-beta(TGF-β)superfamily,bone morphogenetic protein 7(BMP7)has anti-liver fibrosis functions.However,little is known about BMP7 expression changes and its potential regulatory mechanism as well as the relationship between BMP7 and TGF-βduring liver fibrosis.In addition,the mechanism underlying the anti-liver fibrosis function of BMP7 needs to be further explored.AIM To investigate changes in the dynamic expression of BMP7 during liver fibrosis,interactions between BMP7 and TGF-β1,and possible mechanisms underlying the anti-liver fibrosis function of BMP7.METHODS Changes in BMP7 expression during liver fibrosis and the interaction between BMP7 and TGF-β1 in mice were observed.Exogenous BMP7 was used to treat mouse primary hepatic stellate cells(HSCs)to observe its effect on activation,migration,and proliferation of HSCs and explore the possible mechanism underlying the anti-liver fibrosis function of BMP7.Mice with liver fibrosis received exogenous BMP7 intervention to observe improvement of liver fibrosis by using Masson’s trichrome staining and detecting the expression of the HSC activation indicator alpha-smooth muscle actin(α-SMA)and the collagen formation associated protein type I collagen(Col I).Changes in the dynamic expression of BMP7 during liver fibrosis in the human body were further observed.RESULTS In the process of liver fibrosis induced by carbon tetrachloride(CCl4)in mice,BMP7 protein expression first increased,followed by a decrease;there was a similar trend in the human body.This process was accompanied by a sustained increase in TGF-β1 protein expression.In vitro experiment results showed that TGF-β1 inhibited BMP7 expression in a time-and dose-dependent manner.In contrast,high doses of exogenous BMP7 inhibited TGF-β1-induced activation,migration,and proliferation of HSCs;this inhibitory effect was associated with upregulation of pSmad1/5/8 and downregulation of phosphorylation of Smad3 and p38 by BMP7.In vivo experiment results showed that exogenous BMP7 improved liver fibrosis in mice.CONCLUSION During liver fibrosis,BMP7 protein expression first increases and then decreases.This changing trend is associated with inhibition of BMP7 expression by sustained upregulation of TGF-β1 in a time-and dose-dependent manner.Exogenous BMP7 could selectively regulate TGF-β/Smad pathway-associated factors to inhibit activation,migration,and proliferation of HSCs and exert antiliver fibrosis functions.Exogenous BMP7 has the potential to be used as an antiliver fibrosis drug.

Daily genetic profiling indicates JAK/STAT signaling promotes early hepatic stellate cell transdifferentiation

AIM: To identify signaling pathways and genes that initiate and commit hepatic stellate cells (HSCs) to transdifferentiation. METHODS: Primary HSCs were isolated from male Sprague-Dawley rats and cultured on plastic for 0-10 d. Gene expression was assessed daily (quiescent to day 10 culture-activation) by real time polymerase chain reaction and data clustered using AMADA software. The significance of JAK/STAT signaling to HSC transdifferentiation was determined by treating cells with a JAK2 inhibitor. RESULTS: Genetic cluster analyses, based on expression of these 21 genes, showed similar expression profiles on days 1-3, days 5 and 6, and days 7-10, while freshly isolated cells (day Q) and day 4 cells were genotypically distinct from any of the other days. Additionally, gene expression clustering revealed strong upregulation of interleukin-6, JAK2 and STAT3 mRNA in the early stages of activation. Inhibition of the JAK/STAT signaling pathway impeded the morphological transdifferentiation of HSCs which correlated with decreased mRNA expression of several profibrotic genes including collagens, α-SMA, PDGFR and TGFβR. CONCLUSION: These data demonstrate unique clustered genetic profiles during the daily progression of HSC transdifferentiation and that JAK/STAT signaling may be critical in the early stages of transdifferentiation.

Hepatitis B virus X protein promotes proliferation and upregulates TGF-β1 and CTGF in human hepatic stellate cell line,LX-2

BACKGROUND:Chronic hepatitis B virus(HBV)infection is a major cause of liver fibrosis,but the mechanisms underlying HBV-related fibrogenesis are still unknown. Although the roles of HBV X protein(HBx)remain poorly understood,it is thought to play an important role in the regulation of cellular growth and hepatocarcinogenesis. The aim of this study was to determine the role of HBx in liver fibrogenesis by studying the effect of HBx on the proliferation and expression of fibrosis-related molecules in the human hepatic stellate cell line,LX-2. METHODS:We established an in vitro co-culture system with LX-2 cells and a stable QSG7701-HBx cell line which had been transfected with the HBx gene. 3 H-TdR incorporation and flow cytometry were used to determine the effects of HBx on the proliferation of LX-2 cells. α-smooth muscle actin(α-SMA),transforming growth factor-β1(TGF-β1),transforming growth factor-βreceptor Ⅱ(TGF-βRⅡ),and connective tissue growth factor (CTGF)in LX-2 cells were analyzed by Western blotting.In addition,the expression levels of collagen typeⅠ(ColⅠ) from the co-cultured media were measured by ELISA. RESULTS: 3 H-TdR incorporation increased significantly in LX-2 cells co-cultured with QSG7701-HBx cells compared to those cultured with QSG7701-pcDNA3 and QSG7701 (non-tumorigenic human liver cell line).Cell cycle results revealed that HBx accelerated the progression of G1 to S in LX-2 cells.The expressions ofα-SMA,TGF-β1,TGF-βR Ⅱ,CTGF and ColⅠwere significantly increased in the co- cultures of LX-2 cells with stable QSG7701-HBx cells. CONCLUSION:These results suggest that HBx may facilitate liver fibrosis by promoting hepatic stellate cell proliferation and upregulating the expression of fibrosis- related molecules.

Natural taurine promotes apoptosis of human hepatic stellate cells in proteomics analysis

AIM:To study the differential expression of proteins between natural taurine treated hepatic stellate cells and controls, and investigate the underlying regulatory mechanism of natural taurine in inhibiting hepatic fibrosis.METHODS: A proteomic strategy combining two-dimensional gel electrophoresis and ultraperform ance liquid chromatographyelectrospray ionizationtandem mass spectrometry (UPLCESIMS/MS) was used to study the differential expression of proteins and Western blotting was used to validate the results. Gene ontology (GO) method was utilized to analyze the functional enrichment of differentially expressed proteins. Flow cytometry was performed to compare the apoptosis rate between taurinetreated and untreated hepatic stellate cells (HSCs).RESULTS: Nineteen differentially expressed proteins (11 upregulated and 8 downregulated) were identifiedby 2D/MS, and the expression profiles of GLO1 and ANXA1 were validated by Western blotting. GO analysis found that these differentially expressed proteins were enriched within biological processes such as "cellular apoptosis", "oxidation reaction" and "metabolic process" in clusters. Flow cytometric analysis showed that taurinetreated HSCs had a significantly increased apoptosis rate when compared with the control group.CONCLUSION: Natural taurine can promote HSC apoptosis so as to inhibit hepatic fibrosis.

Effects of Fuzhenghuayu decoction on collagen synthesis of cultured hepatic stellate cells,hepatocytes and fibroblasts in rats

AIM To study the mechanism of Fuzhenghuayu (FZHY) decoction on anti liver fibrosis. METHODS FZHY 10% decoction sera was incubated with rat normal subcultured hepatic stellate cells (HSC) and fibrotic primarily cultured HSC, normal and fibrotic hepatocytes and subcultured skin fibroblasts separately. Cell intracellular and extracellular collagen synthesis rates were measured by the method of Proline impulse and collagenase digestion. RESULTS For primarily cultured HSC and hepatocytes, both of intracellular and extracellular collagen synthesis rates decreased in the drug sera group. For the normal subcultured HSC and primarily cultured hepatocytes, the extracellular collagen secretion was decreased obviously by the drug sera, and intracellular collagen synthesis rates were inhibited to some extents. For fibroblasts, both intracellular and extracellular collagen synthesis rates were inhibited some what, but no significant differences were found. CONCLUSION The mechanism of FZHY decoction on anti liver fibrosis may be associated with inhibition of liver collagen production.

Effect of Fuzhenghuayu decoction on vascular endothelial growth factor secretion in hepatic stellate cells

Objective: To investigate the effect of Fuzhenghuayu decoction on autocrine activation of hepatic stellate cell (HSC). Methods: The drug serum containing Fuzhenghuayu decoction was collected from normal rats, and cul- tured with activated HSC in vitro. The conditioned medium from the drug serum treated HSC was added to primary cultured quiescent HSC. Cell prolifera- tion was assayed by tetrazolium colorimetric test, and the contents of type Ⅰ collagen and vascular endo- thelial growth factor (VEGF) in the supernatant were measured with ELISA. Results: The conditioned medium from activated HSC could stimulate the quiescent HSC proliferation and type Ⅰ collagen secretion. The drug serum inhibi- ted this stimulating action and VEGF secretion from the activated HSC. Conclusion: Fuzhenghuayu decoction acts effectively against the autocrine activation pathway of HSC. The mechanism may be associated with the inhibition of the secretion of VEGF by activated HSC.

Phosphatidylinositol 3-kinase/Akt pathway regulates hepatic stellate cell apoptosis

AIM: To investigate the role of phosphatidylinositol 3-kinase (PI 3-K)/Akt signaling pathway in the balance of HSC activation and apoptosis in rat hepatic stellate cells (HSC). METHODS: An activated HSC cell line was used in this study. LY 294002, the PI 3-K/Akt signal pathway block-er was used to investigate the molecular events on apoptosis in HSC and to interpret the role of this path-way in HSC apoptosis. Immunocytochemistry, Western blot and reverse transcription polymerase chain reac-tion (RT-PCR) analysis were applied to detect the ex-pression of PI 3-K, and simultaneously phosphorylated-Akt (p-Akt) and total-Akt were determined by Western blot. The HSC apoptosis was examined by annexin-V/ propidium iodide double-labelled flow cytometry and transmission electron microscopy. RESULTS: The apoptosis rates in LY 294002 (30.82% ± 2.90%) and LY 294002 + PDGF-BB (28.16% ± 2.58%) groups were signif icantly increased compared with those of control (9.02% ± 1.81%) and PDGF-BB (4.35% ± 1.18%). PDGF-BB augmented PI 3-K and p-Akt expres-sion. LY 294002 signif icantly reduced the contents of PI 3-K and p-Akt. mRNA transcription evaluated by RT-PCR showed similar tendencies as protein expression. CONCLUSION: Inhibition of PI 3-K/Akt signaling path-way induces apoptosis in HSC.

Metformin attenuates motility,contraction,and fibrogenic response of hepatic stellate cells in vivo and in vitro by activating AMP-activated protein kinase

AIM To investigate the effect of metformin on activated hepatic stellate cells(HSCs) and the possible signaling pathways involved. METHODS A fibrotic mouse model was generated by intraperitoneal injection of carbon tetrachloride(CCl_4) and subsequent treatment with or without metformin. The level of fibrosis was detected by hematoxylin-eosin staining, Sirius Red staining, and immunohistochemistry. The HSC cell line LX-2 was used for in vitro studies. The effect of metformin on cell proliferation(CCK8 assay),motility(scratch test and Transwell assay), contraction(collagen gel contraction assay), extracellular matrix(ECM) secretion(Western blot), and angiogenesis(ELISA and tube formation assay) was investigated. We also analyzed the possible signaling pathways involved by Western blot analysis.RESULTS Mice developed marked liver fibrosis after intraperitoneal injection with CCl_4 for 6 wk. Metformin decreased the activation of HSCs, reduced the deposition of ECM, and inhibited angiogenesis in CCl_4-treated mice. Platelet-derived growth factor(PDGF) promoted the fibrogenic response of HSCs in vitro, while metformin inhibited the activation, proliferation, migration, and contraction of HSCs, and reduced the secretion of ECM. Metformin decreased the expression of vascular endothelial growth factor(VEGF) in HSCs through inhibition of hypoxia inducible factor(HIF)-1α in both PDGF-BB treatment and hypoxic conditions, and it down-regulated VEGF secretion by HSCs and inhibited HSC-based angiogenesis in hypoxic conditions in vitro. The inhibitory effects of metformin on activated HSCs were mediated by inhibiting the Akt/mammalian target of rapamycin(m TOR) and extracellular signal-regulated kinase(ERK) pathways via the activation of adenosine monophosphate-activated protein kinase(AMPK).CONCLUSION Metformin attenuates the fibrogenic response of HSCs in vivo and in vitro, and may therefore be useful for the treatment of chronic liver diseases.