A Discussion on the Relationship among Hepatic Stellate Cells,Hepatic Sinusoidal Endothelial Cells and Hepatic Sinusoidal Capillarization in the Development of Hepatic Fibrosis

Hepatic stellate cells,hepatic sinusoidal endothelial cells and hepatic sinusoidal capllarization are closely related to the occurrence and progression of hepatic fibrosis.The pathological activation of hepatic stellate cels is the central link of hepatic fibrosis,and hepatic sinusoidal capillarization also promotes the occurrence and development of liver diseases.In the course of hepatic fibrosis,there is always a mutually reinforcing relationship between the activation of hepatic stellate cells and the capillarization of hepatic sinusoids.This paper strives to find an effective way to intervene or even reverse this vicious cycle by deeply investigating the effect of hepatic stellate cells and hepatic sinusoidal capillarization on hepatic fibrosis and their mutual promotion,and provide a new idea for the treatment of hepatic fibrosis,which is of great significance for relieving and reversing hepatic fibrosis.

Effects of interferon-alpha on expression of hepatic stellate cell and transforming growth factor-pi and a-smooth muscle actin in rats with hepatic fibrosis

AIM:To investigate the effect of interferon-a (IFN-α) on preventing or reversing hepatic fibrosis in rat experimental model induced by CCI4. METHODS: One hundred and ten Sprague-Dawley rats were divided into five groups: group A (normal controls, n = 18), group B (fibrotic model controls, n = 22), group C (IFN-α prevention, n = 22) initially treated with intramuscular injection of IFN-a in saline daily at the doses of 1× 105 U for 6 wk, group D (IFN-a treatment, n = 24) treated with intra-muscular injection of IFN-a in saline daily at the doses of 1×105 U for 6 wk after the first 6 wk, group E (0.9% sodium chloride treatment control, n = 24) treated with intra-muscular injection of 0.01 mL/kg daily for 6 wk after the first 6 wk. At the end of the experiment, all rats of each group were killed. Samples of the liver obtained by biopsy were subjected to histological, immunohistochemical and electron microscopic studies for the expressions of transforming growth factor-pi (TGF- μ41) and α-smooth muscle actin (α-SMA). RESULTS: The expressions of TGF-pl, the number of activated hepatic stellate cells and a-SMA in hepatic tissue of group C were significantly less than those of group B (P<0.01). The degree of fibrosis score in group B was also significantly less than that of group C under light microscope (P<0.01). CONCLUSION: IFN-a can inhibit the production of TGF-pl, decrease HSC activation and stimulate its apoptosis.

Oxymatrine liposome attenuates hepatic fibrosis via targeting hepatic stellate cells

AIM： To investigate the potential mechanism of Arg- Gly-Asp （RGD） peptide-labeled liposome loading oxy- matrine （OM） therapy in CCI4-induced hepatic fibrosis in rats. METHODS： We constructed a rat model of CCh- induced hepatic fibrosis and treated the rats with dif- ferent formulations of OM. To evaluate the antifibrotic effect of OM, we detected levels of alkaline phospha- tase, hepatic histopathology （hematoxylin and eosin stain and Masson staining） and fibrosis-related gene expression of matrix metallopeptidase （MMP）-2, tis- sue inhibitor of metalloproteinase （TIMP）-I as well as type I procollagen via quantitative real-time poly- merase chain reaction. To detect cell viability and apop- tosis of hepatic stellate cells （HSCs）, we performed 3-（4,5）-dimethylthiahiazo（-z-yl）-3,5-diphenytetrazoli- umromide assay and flow cytometry. To reinforce the combination of oxymatrine with HSCs, we constructed fluorescein-isothiocyanate-conjugated Arg-Gly-Asp peptide-labeled liposomes loading OM, and its targeting of HSCs was examined by fluorescent microscopy. RESULTS： OM attenuated CCh-induced hepatic fibro- sis, as defined by reducing serum alkaline phosphatase （344.47± 27.52 U/L vs 550.69 ± 43.78 U/L, P 〈 0.05）, attenuating liver injury and improving collagen deposits （2.36% ± 0.09% vs 7.70% ±0.60%, P 〈 0.05） and downregulating fibrosis-related gene expression, that is, MMP-2, TIMP-1 and type I procollagen （P 〈 0.05）. OM inhibited cell viability and induced apoptosis of HSCs in vitro. RGD promoted OM targeting of HSCs and en- hanced the therapeutic effect of OM in terms of serum alkaline phosphatase （272.51 ± 19.55 U/L vs 344.47 ± 27.52 U/L, P 〈 0.05）, liver injury, collagen deposits （0.26%± 0.09% vs 2.36% ± 0.09%, P 〈 0.05） and downregulating fibrosis-related gene expression, that is, MMP-2, TIMP-1 and type I procollagen （P 〈 0.05）. Moreover, in vitro assay demonstrated that RGD en- hanced the effect of OM on HSC viability and apoptosis. CONCLUSION： OM attenuated hepatic fibrosis by in- hibiting viability and inducing apoptosis of HSCs. The RGD-labeled formulation enhanced the targeting effi- ciency for HSCs and the therapeutic effect.

Expression of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-1 in hepatic stellate cells during rat hepatic fibrosis and its intervention by IL-10

AIM: To investigate the expression of matrix metallopr-oteinase-2 and tissue inhibitor of metalloproteinase-1 in hepatic fibrosis and the antifibrogenic role of exogenous interleukin-10 (IL-10). METHODS: Hepatic fibrosis was induced by CCI4 administration and 60 male Sprague-Dawley rats were randomly divided into normal control group (group N, 8 rats), CCI4-induced group (group C, 28 rats) and IL-10-treated group (group I, 24 rats). At the beginning of the 7th and 11th wk, rats in each group were routinely perfused with pronase E and type IV collagenase through portal vein catheter and the suspension was centrifuged by 11% Nycodenz density gradient to isolate hepatic stellate cells (HSCs). RT-PCR was used to analyze mRNA of MMP-2 and TIMP-1 from freshly isolated cells. Densitometric data were standardized with β-actin signals. Immunocytochemistry was performed to detect MMP-2 and TIMP-1 expression in HSC cultured for 72 h. RESULTS: Compared to group N in the 7th wk, MMP-2 and TIMP-1 mRNA increased in group C (P= 0.001/0.001) and group I (P= 0.001/0.009). The level of MMP-2 and TIMP-1 mRNA in group I was significantly lower than that in group C (P= 0.001/0.001). In the 11th wk, MMP-2 mRNA in group I was still lower than that in group C (P = 0.005), but both dropped compared with that in the 7th week (P = 0.001/0.004). TIMP-1 mRNA in group I was still lower than that in group C (P= 0.001), and increased in group C (P= 0.001) while decreased in group I (P = 0.042) compared with that in the 7th wk. Same results were found by immunocytochemistry. CONCLUSION: Expression of MMP-2 and TIMP-1 is increased in hepatic fibrosis. IL-10 exhibits an antifibrogenic effect by suppressing MMP-2 and TIMP-1 expression.

An experimental study of extracellular signal-regulated kinase and its interventional treatments in hepatic fibrosis

BACKGROUND: The pathogenesis of hepatic fibrosis and cirrhosis is still not fully understood. The extracellular signal-regulated kinase (ERK) pathway is involved in the regulation of cell proliferation and differentiation. The aim of this study was to investigate the effects of PD98059, a specific inhibitor of ERK, on the cell cycle, cell proliferation, secretion of type I collagen and expression of cyclin D1 mRNA, CDK4 mRNA and transforming growth factor-beta 1 (TGF-beta 1) mRNA in rat hepatic stellate cells (HSCs) stimulated by acetaldehyde. METHODS: Rat HSCs stimulated by acetaldehyde were incubated with PD98059 at different concentrations. The cell cycle was analysed by flow cytometry. Cell proliferation was assessed by the methyl thiazolyl tetrazolium colorimetric assay. The mRNA expression of cyclin D1, CDK4 and TGF-beta 1 was examined using the reverse transcriptase-polymerase chain reaction. Type I collagen in the culture medium was detected by enzyme-linked immunosorbent assay. RESULTS: 20, 50 and 100 mu mol/L PD98059 significantly inhibited the proliferation and provoked a G0/G1-phase arrest of acetaldehyde-induced HSCs in a dose-dependent manner. The secretion of type I collagen and the expression of cyclin D1, CDK4 and TGF-beta 1 mRNA in acetaldehyde-induced HSCs were markedly inhibited by 50 and 100 mu mol/L PD98059, respectively. CONCLUSIONS: The ERK pathway regulates the cell proliferation, secretion of type I collagen and the expression of TGF-beta 1 mRNA in rat HSCs stimulated by acetaldehyde, which is likely related to its regulative effect on the cell cycle.

Alterations of mast cells and TGF-β1 on the silymarin treatment for CCl_4-induced hepatic fibrosis

AIM: Silymarin is a potent antioxidant, antiinflammatory and anti-fibrogenic agent in the liver, which is mediated by alteration of hepatic Kupffer cell function, lipid peroxidation, and collagen production. Especially, in hepatic fibrogenesis, mast cells are expressed in chronic inflammatory conditions, and promote fibroblast growth and stimulate production of the extracellular matrix by hepatic stellate cells. METHODS: We examined the inhibitory mechanism of silymarin on CCI4-induced hepatic cirrhosis in rats. At 4, 8, and 12 wk, liver tissues were examined histopathologically for fibrotic changes produced by silymarin treatment. RESULTS: In the silymarin with CCU-treated group, increase of hepatic stellate cells and TGF-β1 production were lower than in the CCI4-treated group at early stages. Additionally, at the late fibrogenic stage, expressions of TGF-β1 were weaker and especially not expressed in hepatocytes located in peripheral areas. Moreover, the number of mast cell in portal areas gradually increased and was dependent on the fibrogenic stage, but those of CCI4+silymarin-treated group decreased significantly. CONCLUSION: Anti-fibrotic and antiinflammatory effects of silymarin were associated with activation of hepatic stellate cells through the expression of TGF-β1 and stabilization of mast cells. These results suggest that silymarin prevent hepatic fibrosis through suppression of inflammation and hypoxia in the hepatic fibrogenesis.

Research Progress on the Regulation of Hepatic Sinusoidal Endothelial Cells on Hepatic Fibrosis

Hepatic sinusoidal endothelial cell is a highly differentiated cell in hepatic sinusoid,and plays an important role in the occurrence and development of hepatic fibrosis.The dysfunction of hepatic sinusoidal endothelial cells is considered to be the key cause of a variety of liver diseases.At present,the researches on hepatic fibrosis at home and abroad are mainly focused on inhibiting the activation of hepatic stellate cells and accelerating the hydrolysis of extracellular matrix.However,there are few studies on the important role of the structure and function of hepatic sinusoidal endothelial cells in hepatic fibrosis.This paper reviews the research progress on the effect of hepatic sinusoidal endothelial cells on hepatic fibrosis and its regulatory mechanism in recent years.This paper summarizes the results of the research on the structural characteristics of hepatic sinusoidal endothelial cells,secretion of fibrosis-related cytokines and regulation of hepatic stellate cells activation in the development of hepatic fibrosis.

Effect of bone marrow mesenchymal stem cells on the Smad expression of hepatic fibrosis rats

Objective:To investigate the impact of bone marrow mesenchymal stem cells on Smad expression of hepatic fibrosis rats.Methods:A total of 48 adult female SD rats were randomly divided into three groups,normal control group(n=10),observation group(n=19)with liver fibrosis model rats injected with BMSCs cells:model group(n=19),with liver fibrosis model rats injected with physiological saline.Serum index,TGF-β1 and Smad expression were detected.Results:TypeⅢprocollagen,Ⅳcollagen,hyaluronic acid,laminin levels of observation group were significantly lower than those of model group(P<0.05).The content and expression of TGF-β1in serum and liver tissue of observation group were significantly lower than those of model group(P<0.05).Compared with normal control group,the Smad3,Smad4 mRNA and protein expression of model group were significantly increased,the Smad7 mRNA and protein expression were significantly reduced(P<0.05).Compared with model group.Smad3,Smad4 mRNA and protein expression of observation group were significantly reduced,and Smad7 mRNA expression were significantly increased(P<0.05).Conclusions:BMSCs can regulate Smad expression to some extent,and reduce the degree of liver fibrosis.

CD4+ T cells and natural killer cells: Biomarkers for hepatic fibrosis in human immunodeficiency virus/hepatitis C virus-coinfected patients

AIM To characterize peripheral blood natural killer(NK) cells phenotypes by flow cytometry as potential biomarker of liver fibrosis in human immunodeficiency virus(HIV)/hepatitis C virus(HCV) coinfected patients.METHODS Peripheral mononuclear cells from 24 HIV/HCV(HBVnegative) coinfected and 5 HIV/HCV/HBV seronegative individuals were evaluated. HIV/HCV coinfected patients were divided in to groups: G1, patients with METAVIR F0-F2 and G2, patients with METAVIR F3-F4. NK surface cell staining was performed with: AntiCD3(APC/Cy7), anti-CD56(PE/Cy5), anti-CD57(APC), anti-CD25(PE), anti-CD69(FITC), anti-NKp30(PE), antiNKp46(PE/Cy7), anti-NKG2D(APC), anti-DNAM(FITC); anti-CD62L(PE/Cy7), anti-CCR7(PE), anti-TRAIL(PE), anti-Fas L(PE), anti CD94(FITC). Flow cytometry data acquisition was performed on BD FACSCanto, analyzed using Flow Jo software. Frequency of fluorescence was analyzed for all single markers. Clinical records were reviewed, and epidemiological and clinical data were obtained.RESULTS Samples from 11 patients were included in G1 and from 13 in G2. All patients were on ARV, with undetectable HIV viral load. Liver fibrosis was evaluated by transient elastography in 90% of the patients and with biopsy in 10% of the patients. Mean HCV viral load was(6.18 ± 0.7 log10). Even though, no major significant differences were observed between G1 and G2 regarding NK surface markers, it was found that patients with higher liver fibrosis presented statistically lower percentage of NK cells than individual with low to mild fibrosis and healthy controls(G2: 5.4% ± 2.3%, G1: 12.6% ± 8.2%, P = 0.002 and healthy controls 12.2% ± 2.7%, P = 0.008). It was also found that individuals with higher liver fibrosis presented lower CD4 LT count than those from G1(G2: 521 ± 312 cells/μL, G1: 770 ± 205 cells/μL; P = 0.035).CONCLUSION Higher levels of liver fibrosis were associated with lower percentage of NK cells and LTCD4+ count; and they may serve as noninvasive biomarkers of liver damage.

Small extracellular vesicles encapsulating lefty1 mRNA inhibit hepatic fibrosis

Liver fibrosis is the deposition of extracellular matrix(ECM)in the liver caused by persistent chronic injury,which can lead to more serious diseases such as cirrhosis or cancer.Blocking the effect of transforming growth factorβ1(TGF-β1),one of the most important cytokines in liver fibrosis,may be one of the effective ways to inhibit liver fibrosis.As a kind of natural nano-scale vesicles,small extracellular vesicles(sEvs)have displayed excellent delivery vehicle properties.Herein,we prepared hepatic stellate cell(HSC)-derived sEvs loading left-right determination factor 1(lefty1)mRNA(sEvLs)and we wanted to verify whether they can inhibit fibrosis by blocking the TGF-β1 signaling pathway.The results showed that sEvLs had effective cell uptake and reduced activation of HSCs.Rats that were injected with CCl 4 by intraperitoneal injection for 6 weeks exhibited obvious symptoms of liver fibrosis and were treated with systemically administered sEvLs and free sEvs for 4 weeks.Rats injected with olive oil alone served as sham controls.Administration of sEvLs significantly reduced the area of fibrosis compared with free sEvs.We demonstrated that sEvLs inhibited HSCs activation and ECM production,and promote ECM degradation by downregulatingα-smooth muscle actin(α-SMA),collagen I,tissue inhibitor of metalloproteinase(TIMP)-1 and upregulating matrix metalloprotease(MMP)-1.In summary,as an endogenous delivery vehicle,sEvs could deliver mRNA to attenuate hepatic fibrosis by blocking the TGF-β/Smad signaling pathway.

Correlation between anti-fibrotic effect of baicalin and serum cytokines in rat hepatic fibrosis

AIM： To investigate the correlation between the antifibrotic effect of baicalin and serum cytokine production in rat hepatic fibrosis, METHODS： Forty male Sprague-Dawley rats were divided randomly into four groups： normal control group, model group, baicalin-treated group, and colchicine-treated group. Except for the normal control group, all rats in the other groups were administered with carbon tetrachloride to induce hepatic fibrosis. At the same time, the last two groups were also treated with baicalin or colchicine. At the end of the 8 wk, all animals were sacrificed. Serum alanine aminotransferase （ALl＇）, aspartate aminotransferase （AST）, transforming growth factor （TGF）-β1, tumor necrosis factor （TNF）-α, interleukin （IL）-6 and IL-10 were measured. Liver index, hepatic hydroxyproline content and the degree of liver fibrosis were also evaluated. RESULTS： The levels of ALT, AST and liver index in the baicalin-treated group were markedly lower than those in the model group （ALT： 143.88 ± 14.55 U/L vs 193.58± 24.35 U/L; AST： 263.66 ± 44.23 U/L vs 404.37± 68.29 U/L; liver index： 0.033 ± 0.005 vs 0.049± 0.009, P 〈 0.01）. Baicalin therapy also significantly attenuated the degree of hepatic fibrosis, collagen area and collagen area percentage in liver tissue （P 〈 0.01）. Furthermore, the levels of serum TGF-β1, TNF-α and IL-6 were strikingly reduced in the baicalin-treated group compared with the model group, while the production of IL-10 was up-regulated： （TGF-β1：260.21 ± 31.01 pg/mL vs 375.49 ± 57.47 pg/mL; TNF-α： 193.40±15.18 pg/mL vs 260.04 ± 37.70 pg/mL; IL-α：339.87 ± 72.95 pg/mL vs 606.47 ± 130.73 pg/mL; IL-10：506.22 ± 112.07 pg/mL vs 316.95 ± 62.74 pg/mL, P 〈 0.01）. CONCLUSION： Baicalin shows certain therapeutic effects on hepatic fibrosis, probably by immunoregulating the imbalance between profibrotic and antifibrotic cytokines.

Peroxisome proliferator-activated receptor gamma inhibits hepatic fibrosis in rats

BACKGROUND:Hepatic fibrosis is a necessary step in the development of hepatic cirrhosis.In this study we used lentiviral vector-mediated transfection technology to evaluate the effect of peroxisome proliferator-activated receptor gamma(PPAR-γ) on rat hepatic fibrosis. METHODS:Hepatic fibrosis in rats was induced by CCl4 for 2 weeks(early fibrosis)and 8 weeks(sustained fibrosis).The rats were randomly divided into four groups:normal control, fibrosis,blank vector,and PPAR-γ.They were infected with the recombinant lentiviral expression vector carrying the rat PPAR-γgene by portal vein injection.The liver of the rats was examined histologically and hydroxyproline was assessed.In vitro primary hepatic stellate cells(HSCs)were infected with the recombinant lentiviral expression vector carrying the rat PPAR-γgene.The status of HSC proliferation was measured by the MTT assay.The protein levels of PPAR-γ,α-smooth muscle actin(α-SMA)and type I collagen expression were evaluated by the Western blotting method. RESULTS:In vitro studies revealed that expression of PPAR-γ inhibited expression ofα-SMA and type I collagen in activated HSCs(P<0.01)as well as HSC proliferation(P<0.01).In vivo experiments indicated that in the early hepatic fibrosis group,the hydroxyproline content and the level of collagen I protein in the liver in the PPAR-γtransfected group were not significantly different compared to the hepatic fibrosis group and the blank vector group;whereas the expressions of PPAR-γ andα-SMA were different compared to the hepatic fibrosis group(P<0.01).In the sustained hepatic fibrosis group,there were significant differences in the hydroxyproline content and the expression of PPAR-γ,α-SMA,and type I collagen between each group.CONCLUSION:PPAR-γcan inhibit HSC proliferation and hepatic fibrosis,and suppressα-SMA and type I collagen expression.

Adeno-associated virus mediated interferon-gamma inhibits the progression of hepatic fibrosis in vitro and in vivo

AIM:To investigate the effects of adeno-associated virus (AAV) mediated expression of human interferon-γ for gene therapy in experimental hepatic fibrosis in vitro and in vivo. METHODS: We constructed the recombinant AAV encoding human INF-γ (rAAV- INF-γ) and took the primary rat hepatic stellate cells and carbon tetrachloride induced rats as the experimental hepatic fibrosis model in vitro and in vivo. Immunocytochemistry analysis was used to reveal the expression of α-SMA, the marker protein expressed in hepatic stellate cells. The mRNA expression of TGF-β, TIMP-1, and MMP-13 were analyzed by RT-PCR method. In vivo study, the hydroxyproline content in liver and serum AST, ALT were also detected. RESULTS: In vitro study, AAV vector could mediated efficient expression of human INF-γ, which inhibit the activation of hepatic stellate cells, decrease the expression of α-SMA and mRNA of TIMP-1, TGF-β, with the MMP-13 unchanged. In vivo study, the histological examination revealed that rAAV- INF-γ could inhibit the progression of the hepatic fibrosis. In the rAAV-INF-γ induced group, the hydroxyproline content and serum AST, ALT level were decreased to 177±28 μg/g wet liver, 668.5±140.0, 458.4±123.5 U/L, compare with the fibrosis control group 236±31 μg/g wet liver, 1 019.1±276.3, 770.5±154.3 U/L, respectively (P<0.01). mRNA expression of TIMP-1 in the rAAV-INF-γ induced rat liver was decreased while no significant change was observed in TGF-β and MMP-13. CONCLUSION: All these results indicated that rAAV-INF-γ has potential effects for gene therapy of hepatic fibrosis, which could inhibit the progression of hepatic fibrosis.

Effect of IL-10 on the expression of HSC growth factors in hepatic fibrosis rat

AIM： To study the effect of IL-10 on the expression of growth factors - transforming growth factor-β1 （TGF-β1）, epidermal growth factor （EGF）, hepatocyte growth factor （HGF）and platelet-derived growth factor （PDGF） of hepatic stellate cells （HSCs） of hepatic fibrosis rat and the anti-fibrogenic role of exogenous IL-10. METHODS： Hepatic fibrosis was induced by CCI4 administration intra-peritoneally. Sixty clean male Sprague-Dawley （SD） rats were randomly divided into three groups： normal control group （GN, 8 rats）, hepatic fibrosis model group （GC, 28 rats） and IL-10 treated group （GI, 24 rats）. At the beginning of the 7^th and 11^th wk, rats in each group were routinely perfused with pronase E and type IV collagenase through a portal vein catheter and the suspension obtained from the liver was spun by centrifugation with 11% Nycodenz density gradient to isolate HSCs. Histological examination was used to determine the degree of hepatic fibrosis. RT-PCR was employed to analyze mRNA expression from freshly isolated cells. Immunocytochemistry was performed to detect protein expression in primary cultured HSCs. RESULTS： Rat hepatic fibrosis was developed with the increase of injection frequency of CCl4, and HSCs were successfully isolated. At the 7^th and 11^th wk, TGF-β1, EGF, and HGF mRNA in GC increased obviously compared with GN （P = 0.001/0.042, 0.001/0.001, 0.001/0.001） and GI （P= 0.001/0.007, 0.002/0.001, 0.001/0.001）. For TGF-β1, no difference was observed between GI and GN. For EGF, mRNA level in GI increased compared with GN during the 7^th wk （P= 0.005） and 11^th wk （P= 0.049）. For HGF, mRNA level in GI decreased compared with GN at the 7^th wk （P = 0.001） and 11^th wk （P= 0.021）. Between these two time points, TGF-β1 expression at the 7^th wk was higher than that of the 11^th wk （P = 0.049）, but for EGF, the former was lower than the latter （P = 0.022）. As for PDGF mRNA, there was no significant difference between thesegroups, but difference seemed to exist in protein levels. Results by immunocytochemistry of TGF-β1 and EGF were paralleled with the above findings. CONCLUSION： The expression of TGF-β1, EGF and HGF increased in HSC of hepatic fibrosis rat and decreased after treatment with IL-10. IL-10 plays an anti-fibrogenic role by suppressing growth factors expression.

New role and molecular mechanism of Gadd45a in hepatic fibrosis

AIM: To investigate the role of Gadd45a in hepatic fibrosis and the transforming growth factor (TGF)-beta/ Smad signaling pathway. METHODS: Wild-type male BALB/c mice were treated with CCl4 to induce a model of chronic liver injury. Hepatic stellate cells (HSCs) were isolated from the liver of BALB/c mice and were treated with small interfering RNAs (siRNAs) targeting Gadd45a or the pcDNA3.1-Gadd45a recombinant plasmid. Cellular alpha-smooth muscle actin (alpha-SMA), beta-actin, type I collagen, phospho-Smad2, phospho-Smad3, Smad2, Smad3, and Smad4 were detected by Western blots. The mRNA levels of alpha-SMA, beta-actin, and type I collagen were determined by quantitative real-time (qRT)-PCR analyses. Reactive oxygen species production was monitored by flow cytometry using 2,7-dichlorodihydrofluorescein diacetate. Gadd45a, Gadd45b, anti-Gadd45g, type I collagen, and SMA local expression in liver tissue were measured by histologic and immunohistochemical analyses. RESULTS: Significant downregulation of Gadd45a, but not Gadd45b or Gadd45g, accompanied by activation of the TGF-beta/Smad signaling pathways was detected in fibrotic liver tissues of mice and isolated HSCs with chronic liver injury induced by CCl4 treatment. Overexpression of Gadd45a reduced the expression of extracellular matrix proteins and alpha-SMA in HSCs, whereas transient knockdown of Gadd45a with siRNA reversed this process. Gadd45a inhibited the activity of a plasminogen activator inhibitor-1 promoter construct and (CAGA)(9) MLP-Luc, an artificial Smad3/4-specific reporter, as well as reduced the phosphorylation and nuclear translocation of Smad3. Gadd45a showed protective effects by scavenging reactive oxygen species and upregulating antioxidant enzymes. CONCLUSION: Gadd45a may counteract hepatic fibrosis by regulating the activation of HSCs via the inhibition of TGF-beta/Smad signaling.

Bioinformatics analysis of hepatic fibrosis based on hepatic stellate cells

Objective:To analyze differentially expressed genes in human hepatic stellate cells(HSCs)based on data from the GEO database and to identify important target genes for hepatic fibrosis(HF).Methods:In GEO database,microarray GSE11954 of the GEO database was used to obtain data on differential gene expression in human HSCs and was analyzed using GEO2R,using a P value of<0.01 and log2FC value of≥2 for the screening.The genes were input into the DAVID database for enrichment analysis of genes and pathways,followed by protein interaction analysis and module analysis.The results were compared with the results found through text mining.Results:Two hundred sixty two differentially expressed genes(DEGs)were identified.The results of gene bulk enrichment showed that the functional molecules encoded by the DEGS were mainly located in the cytoplasm,extracellular matrix and nucleosome,while the molecular functions were mainly related to"regulating actin binding","protein kinase binding"and"kinase activity".The biological processes they were found to be involved in"regulating cell division","immune response"and"collagen decomposition reaction".KEGG signaling pathway analysis found that they were mainly involved in"cell cycle signaling pathway","ECM receptor interaction signaling pathway","p53 signaling pathway"and"FOXO signaling pathway".Text mining results suggested that MMP1 and ETV6 are potential molecular targets for HF therapy.Conclusion:The results of bioinformatics analysis identified targets and signaling pathways involved in the pathogenesis of HF,but these require further experimental verification.

Involvement of 90-kuD ribosomal S6 kinase in collagen type Ⅰ expression in rat hepatic fibrosis

AIM： To investigate the relationship between 90-kuD ribosomal $6 kinase （pg0RSK） and collagen type I expression during the development of hepatic fibrosis in vivo and in vitro.METHODS： Rat hepatic fibrosis was induced by intraperitoneal injection of dimethylnitrosamine. The protein expression and cell location of p90RSK and their relationship with collagen type I were determined by co-immunofluoresence and confocal microscopy.Subsequently, RNAi strategy was employed to silence p90RSK mRNA expression in HSC-T6, an activated hepatic stellate cell （HSC） line. The expression of collagen type I in HSC-T6 cells was assessed by Western blotting and real-time polymerase chainreaction. Furthermore, HSCs were transfected with expression vectors or RNAi constructs of p90RSK to increase or decrease the p90RSK expression, thencollagen type I promoter activity in the transfected HSCs was examined by reporter assay. Lastly HSC-T6 cells transfected with p90RSK siRNA was treated withor without platelet-derived growth factor （PDGF）-BB at a final concentration of 20μg/L and the cell growthwas determined by MTS conversion.RESULTS： In fibrotic liver tissues, p90RSK was over-expressed in activated HSCs and had a significantpositive correlation with collagen type I levels.In HSC-T6 cells transfected with RNAi targeted top90RSK, the expression of collagen type I was down-regulated （61.8% in mRNA, P 〈 0.01, 89.1% inprotein, P 〈 0.01）. However, collagen type ] promoteractivity was not increased with over-expression of p90RSK and not decreased with low expression either,compared with controls in the same cell line （P = 0.076）.Furthermore, p90RSK siRNA exerted the inhibitionof HSC proliferation, and also abolished the effect of PDGF on the HSC proliferation.CONCLUSION： p90RSK is over-expressed in activatedHSCs and involved in regulating the abnormalexpression of collagen type I through initiating theproliferation of HSCs.

Role of iron in hepatic fibrosis: One piece in the puzzle

Iron is an essential element involved in various biological pathways. When present in excess within the cell, iron can be toxic due to its ability to catalyse the formation of damaging radicals, which promote cellular injury and cell death. Within the liver, iron related oxidative stress can lead to fibrosis and ultimately to cirrhosis. Here we review the role of excessive iron in the pathologies associated with various chronic diseases of the liver. We also describe the molecular mechanism by which iron contributes to the development of hepatic fibrosis.

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.

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.