miR-144 regulates transforming growth factor-β1 iduced hepatic stellate cell activation in human fibrotic liver

Objectives: Activation of hepatic stellate cells (HSCs) into collagen producing myofibroblasts is critical for pathogenesis of liver fibrosis. Transforming growth factor-β1 (TGF-β1) is one of the main profibrogenic mediators for HSC transdifferentiation. Recent studies have shown effect of microRNAs (miRNAs) on regulating TGF-β1-induced HSC activation during liver fibrosis. Here, we aimed to explore the roles of miR-144 and miR-200c in human liver fibrosis. Methods: Expression of TGF-β1 was detected in 42 fibrotic and 18 normal human liver tissues by quantitative real time polymerase chain reaction (qRT-PCR) and immunohistochemistry, and its correlation with α-smooth muscle actin (α-SMA) was calculated. miR-144 and miR-200c expression level in fibrotic liver tissues were also detected by qRT-PCR. The correlation of TGF-β1 expression with miR-200c and miR-144 in the fibrotic liver was analyzed. Results: The results showed that TGF-β1 expression was much higher in fibrotic liver than that in normal liver tissues (P<0.05). TGF-β1 protein high expressing liver fibrosis showed α-SMA positive cells in the liver parenchyma indicating activated HSCs. Expression of TGF-β1 in fibrotic liver was significantly correlated with α-SMA expression (R=0.633, P<0.001). Furthermore, miR-144 was less expressed in liver fibrosis (P<0.05) and was significantly correlated with expression of TGF-β1 in fibrotic liver tissues (R=-0.442, P<0.01). However, miR-200c did not show significant difference between normal and fibrotic liver (P=0.48) and correlation with TGF-β1 expression (R=0.106, P=0.51). Conclusion: All the results indicate that miR-144 can be a novel regulator of TGF-β1-induced HSC activation during liver fibrosis.     

Leptin reduces microRNA-122 level in hepatic stellate cells in vitro and in vivo

Obese patients, often accompanied by hyperleptinemia, are more likely to develop liver fibrosis. Leptin, an adipocyte-derived hormone, augments inflammatory in liver and promotes hepatic stellate cell (HSC) activation (a key step for liver fibrogenesis) and liver fibrosis. microRNA-122 (miR-122) is the most abundant liver-specific miRNA and can attenuate liver fibrosis. This study examined the effect of leptin on miR-122 level in HSCs in vivo and in vitro. Results demonstrated that leptin reduced the levels of both miR-122 (mature miR-122) and primary miR-122 (pri-miR-122). The effects of leptin on the levels of miR-122 and pri-miR-122 were through at least hedgehog pathway. Leptin-induced decrease in sterol regulatory element-binding protein-1c (SREBP-1c) has been shown to contribute to leptin-induced HSC activation. We revealed a mutual promotional effect between SREBP-1c and miR-122. Further experiments indicated that miR-122 inhibited leptin-induced liver fibrosis in leptin-deficient mouse model. These data have potential implications for clarifying the mechanisms of hepatic fibrogenesis associated with elevated leptin level in human such as obese patients     

miR-29b介导的TGF-β/Smad信号通路对大鼠肝纤维化进程的影响

目的:初步研究微小RNA-29b(mi R-29b)介导的TGF-β/Smad信号通路在肝星状细胞(HSC)活化中的作用及其对大鼠肝纤维化进程的影响。方法:构建肝纤维化大鼠模型并分离其HSC,同时通过体外获取并鉴定正常大鼠HSC。运用RT-qPCR和Western blot检测以上获取细胞中mi R-29b、TGF-β/Smad信号通路相关蛋白和肝纤维化标志蛋白的变化水平,并通过双萤光素酶报告基因检测系统鉴定mi R-29b对TGF-β1的直接靶向结合情况。结果:随着HSC活化加深,mi R-29b的表达量逐渐减少(P 0. 01),而HSC活性标志物I型胶原蛋白和α-平滑肌肌动蛋白的表达量逐渐增加(P 0. 01)。在TGF-β/Smad信号通路中,Smad2/3/4的表达显著增加,而Smad7的表达明显下降(P 0. 01)。双萤光素酶报告基因检测结果显示,mi R-29b可直接结合于TGF-β1 3’UTR的"UCUCUCCGU"序列,表明TGF-β1为mi R-29b的一个下游靶基因。结论:mi R-29b可参与抑制HSC的活化和迁移,进而抑制肝纤维化进程,而其生物学功能可能是通过直接靶向抑制TGF-β1进而调控TGF-β/Smad信号通路实现的。     

Inhibition of connective tissue growth factor suppresses hepatic stellate cell activation in vitro and prevents liver fibrosis in vivo

Activation of hepatic stellate cells (HSC) represents a critical event in fibrosis, and connective tissue growth factor (CTGF) plays a profibrotic activity and a key factor in the pathogenesis of tissue fibrosis. The current study aimed to determine whether lentivirus-mediated short hairpin RNA (shRNA)–targeted CTGF downregulates the CTGF expression and furthermore whether it suppresses the activation and proliferation of HSC in vitro and prevents liver fibrosis in vivo. HSC-T6 cells were treated with recombinant lentivirus carrying CTGF siRNA. Real-time PCR, Western blotting, MTT, and flow cytometry were performed to investigate the activation and proliferation of HSC-T6 cells in response to CTGF silence. CCl₄-induced rats were received lentivirus containing CTGF siRNA by intraportal vein injection. Levels of liver fibrosis were assessed by biochemical and histopathologic examinations. Recombinant lentivirus containing CTGF siRNA could effectively and specifically downregulate the expression of CTGF in both HSC-T6 cells and CCl₄-induced rats with liver fibrosis. Blockade of CTGF resulted in significant inhibition of HSC activation and proliferation with decrease in TIMPs, MMP2, MMP9, and collagen I, as well as increase in cells in S phase. Silencing CTGF expression with siRNA prevented liver fibrosis in CCl₄-induced rat model. These findings indicated that CTGF plays a key role in the pathogenesis of liver fibrosis and lentiviral-mediated CTGF siRNA has the potential to be an effective treatment for liver fibrosis.     

Dimethyl sulfoxide inhibits dimethylnitrosamine-induced hepatic fibrosis in rats

We studied the preventive effects of dimethyl sulfoxide (DMSO) on experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. Treatment with DMN caused a significant decrease in body and liver weight. Oral DMSO (2 ml/kg daily for 4 weeks) essentially prevented this DMN-induced body and liver weight loss with no major side effects. DMSO suppressed the induction of hepatic fibrosis, as determined by histological evaluation, and reduced hepatic hydroxyproline. It also suppressed the expression of mRNA for type I collagen in the liver. Because hepatic stellate cells (HSC) are the major cellular source of the collagen in hepatic fibrosis, we examined the effects of DMSO on collagen production in vitro using rat primary HSC culture. However, it was found that DMSO did not inhibit the collagen production in vitro. We next evaluated the effects of DMSO on tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO) production by Kupffer cells, because these factors represent major activator of HSC, and because monocyte-macrophage infiltration has been implicated as being pathogenetically important for hepatic fibrosis induced by DMN. DMSO inhibited lipopolysaccharide (LPS)-induced TNFalpha and NO production, and reduced TNFalpha mRNA levels. DMSO also suppressed the LPS-induced nuclear factor kappa B activation in a murine macrophage-like cell line. These results suggest that the inhibitory effects of DMSO on hepatic fibrosis may be primarily exerted via blocking of DMN-induced inflammation. These results also implied that DMSO may be potentially useful for preventing the development of hepatic fibrosis.     

The role of C/EBP-α expression in human liver and liver fibrosis and its relationship with autophagy

Aim: To investigate the expression of CCAAT enhancer binding protein-α (C/EBP-α) in normal human liver and liver fibrosis and its probable association with autophagy. Methods: Double label immunohistochemistry was used to detect the location of C/EBP-α in hepatocytes and hepatic stellate cells (HSCs). The expression of C/EBP-α, Atg5, and Atg6 was also evaluated by immunohistochemistry in paraffin sections of human liver. HSC-T6 cells were treated with rapamycin and 3-methyladenine (3MA) to induce or inhibit autophagy, and the expression of C/EBP-α protein was detected by Western blotting. Results: Double label immunohistochemistry showed that C/EBP-α was predominantly located in hepatocytes and that its expression was significantly decreased in fibrosis compared with normal liver. Atg5 expression was increased in fibrosis but was located primarily in liver septa and peri-vascular areas, which was consistent with the distribution of HSCs. In contrast, Atg6 was not expressed in normal or fibrotic liver. Treatment of HSC-T6 cells in culture with rapamycin or 3MA decreased or increased C/EBP-α expression, respectively, as shown by Western blotting. Conclusion: C/EBP-α was primarily expressed in hepatocytes in normal liver, but its expression decreased significantly in liver fibrosis. Autophagy might play a role in liver fibrosis through its association with C/EBP-α, but this hypothesis warrants further investigation.     

Huangqi decoction inhibits apoptosis and fibrosis, but promotes Kupffer Cell activation in dimethylnitrosamine-induced rat liver fibrosis

ABSTRACT: BACKGROUND: Previously, Huangqi decoction (HQD) has been found to have a potential therapeutic effect on DMN-induced liver cirrhosis. Here, the mechanisms of HQD action against liver fibrosis were investigated in relation to hepatocyte apoptosis and hepatic inflammation regulation. METHODS: Liver fibrosis was induced by DMN administration for 2 or 4 weeks. Hepatocyte apoptosis and of Kupffer cells (KC) and hepatic stellate cells (HSC) interaction were investigated using confocal microscopy. The principle cytokines, fibrogenic proteins and apoptotic factors were investigated using western blot analysis. RESULTS: Compared with the DMN-water group, HQD showed decreased hepatocyte apoptosis and reduced expression of apoptotic effectors, cleaved-caspase-3, and fibrotic factors, such as smooth muscle alpha-actin (alpha-SMA), transforming growth factor beta-1 (TGF-beta1). However, the KC marker CD68 increased significantly in DMN-HQD liver. Confocal microscopy demonstrated widespread adhesion of KCs to HSCs in DMN-water and DMN-HQD rats liver. CONCLUSIONS: HQD exhibited positive protective effects against liver fibrosis; its mechanism of action was associated with protection from hepatocyte apoptosis and the promotion of CD68 expression in the devolopment of liver fibrosis to cirrhosis development.     

Knockdown of miR-23, miR-27, and miR-24 Alters Fetal Liver Development and Blocks Fibrosis in Mice

MicroRNAs (miRNAs) regulate cell fate selection and cellular differentiation. miRNAs of the miR23b polycistron (miR-23b, miR-27b, and miR-24) target components of the TGF-β signaling pathway and affect murine bile ductular and hepatocyte cell fate selection in vitro. Here we show that miR-23b polycistron miRNAs directly target murine Smad4, which is required for TGF-β signaling. Injection of antagomirs against these miRNAs directly into E16.5 murine fetuses caused increased cytokeratin expression in sinusoids and primitive ductular elements throughout the parenchyma of newborn mice. Similar antagomir injection in newborn mice increased bile ductular differentiation in the liver periphery and reduced hepatocyte proliferation. Antagomir injection in newborn Alb/TGF-β1 transgenic mice that develop fibrosis inhibited the development of fibrosis, and injection of older mice caused the resolution of existing fibrosis. Furthermore, murine stellate cell activation, including ColA1 and ACTA2 expression, is regulated by miR-23b cluster miRNAs. In summary, knockdown of miR-23b cluster miRNAs in fetal and newborn liver promotes bile duct differentiation and can block or revert TGF-β-induced liver fibrosis that is dependent on stellate cell activation. These data may find practical application in the highly needed development of therapies for the treatment of fibrosis.Key words: Alb/TGF-β1, MicroRNA, miR-23, miR-27, miR-24, Liver, Liver fibrosis, Cell fate, Differentiation, Hepatic progenitors     

海马注射miR-181c对CCI模型大鼠热痛的影响

目的:观察大鼠海马CA1区注射miR-18Ic激动剂/抑制剂对坐骨神经缩窄性损伤(CCI)大鼠热痛及海马炎症因子和转录因子表达的影响。方法:成年雄性SD大鼠随机分为6组,分别是假手术组(Sham)、CCI模型组(CCI)、CCI+miR-181c激动剂阴性对照组、CCI+miR-181c抑制剂阴性对照组、CCI+miR-181c激动剂组和CCI+miR-I8le抑制剂组。在术前1 d,术后第1、3、5、7 d测定热缩足潜伏期(TWL)。连续7 d给药后取海马,real time RT-PCR、ELISA及Western Blot检测TLR4、炎症因子(TNF-α和IL-1β)和转录因子(CTCF和Nrt2)表达。结果:与Sham组相比,CCI组大鼠TWL缩短(P<0.05),海马miR-18Ic表达下降(P<0.05),TLR4.TNF-a和IL-1βmRNA表达上调(P<0.05),IL-1β和TNF-α含量增多(P<0.05);与CCI组相比,注射miR-181c激动剂后CCI大鼠TWL延长(P<0.05),海马miR-181c表达上调(P<0.05),而TLR4、TNF-α和IL-IβmRNA表达下降(P<0.05),IL-1β和TNF-c含量下降(P<0.05);注射miR-181c抑制剂则TWL降低(P<0.05),CCI大鼠海马miR-18lc表达进一步下降(P<0.05),TLR4、TNF-α和IL-IβmRNA表达进一步上升(P<0.05),IL-1β和TNF-α含量上升(P<0.05)。与Sham组相比,CCI组海马CTCF表达下降,Nrf2在胞核表达上升(P<0.05)。结论:海马注射miR-181c激动剂减轻CCI大鼠热痛敏可能是由于miR-181e下调TLR4和TNF-α表达导致。CCI大鼠海马miR-181e表达下调可能与CTCF低表达有关。     

大鼠肝纤维化与microRNA-181a调控肝星状细胞自噬的关系

目的:观察四氯化碳(CCl4)诱导肝纤维化(HF)大鼠肝脏结构的改变、肝组织中转化生长因子β1(TGF-β1)、微小RNA-181a(microRNA-181a)、自噬标志性蛋白LC3-Ⅱ/-Ⅰ和beclin-1水平及胶原沉积的变化,以及microRNA-181a对TGF-β1诱导大鼠肝星状细胞(HSCs)自噬的作用,探讨microRNA-181a调控HSCs活化及HF的可能机制。方法:(1)40只健康雄性Wistar大鼠随机分为空白对照(control)组和CCl4诱导HF模型2周(W2)、4周(W4)、6周(W6)及8周(W8)组,每组8只。control组给予皮下注射橄榄油3 mL/kg;W2、W4、W6及W8组给予皮下注射40%CCl4(4∶6混合橄榄油)3 mL/kg,每周2次,分别连续作用2、4、6及8周;Masson染色评估大鼠HF改变;ELISA法检测大鼠血清及肝组织中TGF-β1的水平;RT-qPCR检测肝组织中microRNA-181a的表达;Western blot检测肝组织中LC3-Ⅱ/-Ⅰ、beclin-1、α-平滑肌肌动蛋白(α-SMA)、Ⅰ型胶原(Col Ⅰ)和Ⅲ型胶原(ColⅢ)的蛋白水平;(2)microRNA-181a inhibitor转染大鼠HSC-T6细胞,或采用自噬抑制剂3-甲基腺嘌呤(3-MA)预处理细胞后,以TGF-β1诱导细胞自噬,RT-qPCR和Western blot分别检测HSC-T6细胞中microRNA-181a的表达及LC3-Ⅱ/-Ⅰ、beclin-1、α-SMA、Col Ⅰ和ColⅢ的蛋白水平。结果:(1)大鼠肝组织中TGF-β1和micro RNA-181a表达、自噬标志性蛋白LC3-Ⅱ/-Ⅰ比值和beclin-1水平均随HF程度加重而呈上升趋势,microRNA-181a表达水平与细胞自噬呈正相关(P<0.01);(2)体外TGF-β1诱导HSC-T6细胞自噬及活化时伴有microRNA-181a表达显著上调;转染microRNA-181a inhibitor后HSC-T6细胞中microRNA-181a表达显著下降,细胞自噬及活化受到显著抑制(P<0.01),这一结果与3-MA作用相似。结论:CCl4呈时间依赖性地促进大鼠HF,上调肝组织microRNA-181a表达及自噬水平;降低HSC-T6细胞microRNA-181a表达可抑制TGF-β1诱导的细胞自噬;大鼠HF与microRNA-181a调控HSCs自噬有关。     

Inhibitory effects of dimethyl α-ketoglutarate in hepatic stellate cell activation

Aim: The activation of Hepatic stellate cell (HSC) is a pivotal event in the initiation and progression of hepatic fibrosis and a major source of collagen deposition. A recent study found that autophagy fuels the HSC activation. α-ketoglutarate (AKG), an intermediate in the Kerbs CYCLE, has been shown to regulate the level of autophagy. In this study, we aim to investigate the potential effect of dimethyl α-ketoglutarate (DMKG), a membrane-permeable esters of AKG, on the activation of HSC. Methods: HSC and hepatocyte cell lines were treated with DMKG at gradient concentrations, MTT assay was used to assess the cell viability. Concentrations of DMKG that did not affect the cell survival were added to the culture media of HSC cells. Real-time PCR and western blot analysis was carried out to evaluate the expression of fibrogenic genes in HSC after culture for 24 hours. Results: Low dose of DMKG had little cytotoxicity to both HSCs and hepatocytes, while HSCs were more vulnerable to high dose of DMKG than hepatocytes. More importantly, DMKG inhibited the expression of α-SMA and collagen I significantly in HSCs detected by real-time PCR and western blot analysis at the concentrations that didn’t decrease cell viability. Conclusions: DMKG has a significant role of inhibiting the activation of HSC and may attenuate hepatic fibrosis safely.     

DcR3 对肝纤维化动物模型的影响

目的:研究DcR3 基因对肝纤维化大鼠的预防性治疗的作用。方法:SPF 级健康雄性Wistar 大鼠30 只,体重范围180 ~220 g,随机分为3 组,每组10 只,分别为正常对照组、DcR3 基因预防性治疗组(1% DMN+DcR3 组)、造模组(1%DMN 组)。采用1%DMN 诱导大鼠肝纤维化模型,腹腔注射DcR3 质粒进行预防性干预。分别采用HE 染色和Masson 染色观察肝组织病理情况;qRT-PCR 和Western blot 法检测DcR3、Fas、FasL、-SMA 和TGF-1 的mRNA 和蛋白表达水平。结果:与模型组相比,DcR3 预防治疗组大鼠肝组织炎性细胞浸润及胶原类物质沉积有所改善;DcR3 基因可显著降低肝纤维化大鼠Fas、FasL、 SMA 和TGF-1 mRNA 和蛋白表达水平,DcR3 基因预防性治疗组与对照组和造模组有显著性差异(P<0.05);同时DcR3 基因预防性治疗组DcR3 mRNA 和蛋白表达水平显著升高(P<0.05)。结论:DcR3 基因可有效防治大鼠肝纤维化,其作用机制可能是DcR3 通过降低肝脏炎症反应,减少胶原类物质沉积,抑制 SMA 和TGF-1 表达,从而抑制HSC 活化;下调Fas和FasL 表达,抑制Fas/ FasL 途径诱导的肝细胞凋亡。     

PTEN expression is down‐regulated in liver tissues of rats with hepatic fibrosis induced by biliary stenosis

The gene phosphatase and tensin homolog deleted on chromosome 10 (PTEN) codes for a tumor‐suppressor phospholipid phosphatase. Deletion, mutation or abnormal expression of PTEN is commonly found in many kinds of malignant tumors. At the time of this study, though, the role of PTEN expression in the pathology of hepatic fibrosis remains unclear. In this study, we investigate the dynamic expression of PTEN in a rat model of hepatic fibrosis, with special emphasis on the activation and proliferation of hepatic stellate cells (HSC) in vivo. The rat model of hepatic fibrosis used in this study employed common bile duct ligation. At four time points, the expression of PTEN in hepatic tissues and activated HSC in rat liver tissues was measured by immunohistochemical staining, Western blotting, real‐time fluorescent quantitative PCR and immunofluorescence confocal laser scanning microscopy, respectively. Further, α‐smooth muscle actin (α‐SMA), an activated HSC marker in rat liver tissues, was detected by immunohistochemical staining. This study showed that aggravation of hepatic fibrosis led to gradually decreasing expression of PTEN in the hepatic tissues. Further, as hepatic fibrosis worsens, PTEN‐expressing activated HSC accounts for an increasingly smaller percentage of all activated HSC. In contrast, the percentage of α‐SMA‐expressing HSC cells increases significantly. In conclusion, expression of PTEN mRNA and protein is down‐regulated in fibrogenic rat liver tissue, and its expression in HSC in vivo also decreases with progression of fibrosis. Thus, these results show that the dynamic expression of PTEN in hepatic tissues negatively correlates with activation and proliferation of HSC.     

肝纤维化形成过程中瘦素的表达变化

目的：观察二甲基亚硝胺(DMN)诱导实验性肝纤维化模型大鼠肝纤维化形成过程中瘦素(Leptin)的表达变化。方法：模型组大鼠腹腔注射10 mg/kg体质量的DMN生理盐水溶液,于注射后的1、2、3周末处死动物,分别采用半定量逆转录聚合酶链反应(RT-PCR)及免疫组化法检测瘦素mRNA和蛋白质的表达。结果：正常肝脏无瘦素蛋白表达,给药后第1周仅见少数中央静脉的内皮细胞以及极少量的窦周细胞表达阳性。第2周,则见瘦素表达明显增强,主要分布在纤维增生区域。第3周,瘦素表达进一步增强。正常肝脏组织未检测到mR- NA的表达。而注射DMN 1、2、3周,可见清晰的346 bp瘦素mRNA的条带,表达随时间逐渐增强。结论：瘦素与肝纤维化的进展有关,在肝纤维化的中晚期起重要作用。     

Down-regulation of tTG expression by RNAi inhibits HSC proliferation and attenuates liver fibrosis

Purpose: Expressed in hepatic stellate cell (HSC), tTG is involved in fibrotic diseases including human hepatic fibrosis by promoting the cross-linking of ECM and participating in the initiation and/or progression of liver fibrosis. The purpose of this study is to identify whether depletion of tTG could attenuate liver fibrosis. Methods: In this study, primary hepatic stellate cells were isolated, purified, and cultured from rat. Expression of tTG gene was downregulated by lentivirus-mediated RNAi, and the effects on the activation, proliferation and apoptosis of HSC were investigated both in vitro and in vivo. Results: Lentivirus-mediated RNAi successfully reduced the endogenous expression of tTG in cultured cells. The down-regulation of tTG markedly inhibited the proliferation of HSC and attenuated the synthesis of Collagen-1. The downregulation of tTG also markedly reduced the level of tTG and hydroxyproline induced by CCl₄ in rat livers at week 8 and week 12 after injection of CCl₄. Conclusions: In summary, tTG plays an important role in liver fibrosis. Lentivirus-mediated downregulation of tTG showed a potential anti-fibrosis effect in rats, providing new evidence that the involvement of tTG in HSC activation, also suggesting that RNAi-directed targeting of tTG may be used as a potent and specific therapeutic tool for the treatment of liver fibrosis, especially in inhibiting the activation of HSC.     

BMP-7 attenuates liver fibrosis via regulation of epidermal growth factor receptor

The aim of this study was to elucidate the effect of bone morphogenetic protein-7 (BMP-7) on liver fibrosis induced by carbon tetrachloride (CCl4) in vivo and on the hepatic stellate cells (HSC) activation in vitro. In vivo, thirty male ICR mice were randomly allocated to three groups, the control group (n = 6), the CCl4 group (n = 18) and the BMP-7+CCl4 group (n = 6). The model of liver fibrosis was induced by intraperitoneal injection with CCl4 three times per week lasting for 12 weeks in CCl4 group and the BMP-7+CCl4 group. After 8 weeks injection with CCl4, mice were intraperitoneal injected with human recombinant BMP-7 in BMP-7+CCl4 group. Meanwhile, mice in the CCl4 group were only intraperitoneal injection with equal amount of saline. The degree of liver fibrosis was assessed by HE and Masson’s staining. PCR and western blot were used to detect mRNA and protein levels. In BMP-7+CCl4 group, serum levels of alanine aminotransferase (ALT) and aminotransferase (AST) were decreased and serum albumin (Alb) was increased. Meanwhile, the expressions of transforming growth factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA) were down-regulated by BMP-7 intervention as compared to the CCl4 group (P < 0.05). Furthermore, BMP-7 also suppressed the expression of epidermal growth factor receptor (EGFR) and phosphorylated-epidermal growth factor receptor (pEGFR). HE and Masson stain showed that liver damage was alleviated in BMP-7+CCl4 group. In vitro study, expression of EGFR, TGF-β1 and α-SMA were down regulated by BMP-7 dose-dependently, indicating it might effect on suppression of HSC activation. Therefore, our data indicate BMP-7 was capable of inhibiting liver fibrosis and suppressing HSCs activation, and these effects might rely on its crosstalk with EGFR and TGF-β1. We suggest that BMP-7 may be a potential reagentfor the prevention and treatment of liver fibrosis.     

F2-isoprostanes stimulate collagen synthesis in activated hepatic stellate cells: a link with liver fibrosis?

Carbon tetrachloride (CCl4)-induced hepatic fibrosis has been considered to be linked to oxidative stress and mediated by aldehydic lipid peroxidation products. In the present study, we investigated whether collagen synthesis is induced by F2-isoprostanes, the most proximal products of lipid peroxidation and known mediators of important biological effects. By contrast with aldehydes, F2-isoprostanes act through receptors able to elicit definite signal transduction pathways. In a rat model of CCl4-induced hepatic fibrosis, plasma F2-isoprostanes were markedly elevated for the entire experimental period; hepatic collagen content also increased. When hepatic stellate cells (HSCs) from normal liver were cultured with F2-isoprostanes in the concentration range found in the in vivo studies (10(-9)-10(-8) M), a striking increase in DNA synthesis (reversed by the thromboxane A2 antagonist SQ 29 548), in cell proliferation and in collagen synthesis was observed. Total collagen content was similarly increased. Moreover, F2-isoprostanes markedly increased the production of transforming growth factor-beta1 by U937 cells, considered a model of liver macrophages. The data provide evidence for the possibility that F2-isoprostanes generated by lipid peroxidation in hepatocytes mediate HSC proliferation and collagen production seen in hepatic fibrosis.     

miR-34a promotes liver fibrosis in patients with chronic hepatitis via mediating Sirt1/p53 signaling pathway

PurposeThis research aimed to explore the correlation between miR-34a expression in peripheral blood and clinical characteristics of patients with chronic hepatitis C (CHC) as well as the diagnostic and prognostic values of serum miR-34a in CHC.MethodsSerum samples of 41 CHC patients and 18 normal participants were collected to examine the expression levels of miR-34a using qRT-PCR. The changes of serum TBA, liver enzyme AST and ALT were also determined by enzyme colorimetry and rate method. The levels of serum fibrotic markers hyaluronic acid (HA), type III procollagen (PCIII), type IV collagen (IV-C) and laminin (LN) were detected by radioimmunoassay. Degree of liver fibrosis was examined by liver biopsy. Western blot analysis was used to investigate the expression of ac-p53, p53 and Sirt1 in the liver tissues of CHC patients.ResultsMiR-34a was significantly increased in the serum of CHC patients than that in healthy participants, and serum miR-34a was correlated with liver fibrosis index. Serum TBA, AST and ALT levels, and AST/ALT ratios in patients with CHC were increased with increasing degree of fibrosis, and were positively associated with serum miR-34a. Furthermore, the liver tissues of CHC patients showed low Sirt1 protein expression and highly ac-p53 protein expression.ConclusionsSerum miR-34a in patients with CHC could promote liver fibrosis through mediating the Sirt1/p53 pathway and might function as pivotal biomarker on the prognosis and diagnosis of CHC patients.