siRNA对肝纤维化的抑制作用

目的:研究肝星状细胞(HSC)中smad2特异性小干扰RNA(siRNA)对Ⅰ型胶原表达的抑制作用,探讨抗肝纤维化的基因治疗新方法。方法:设计合成靶向Smad2基因的siRNA,将筛选成功的siRNA瞬时转染入体外培养的肝星状细胞(HSC),并给予转化生长因子β(TGF-β)刺激,应用RT-PCR和Western blot技术检测对照组与实验组Ⅰ型胶原mRNA水平和蛋白水平表达差异,研究siRNA对Ⅰ型胶原表达的抑制作用。结果:siRNA能明显降低肝星状细胞中Smad2的RNA和蛋白的表达水平,证实筛选的siRNA有效,能特异性抑制Smad2的基因表达;TGF-β刺激肝星状细胞后,与对照组比较,siRNA转染组细胞外基质(ECM)成分Ⅰ型胶原的表达水平明显降低(P<0.05)。结论:siRNA能够抑制TGFβ对肝星状细胞的激活,阻断TGFβ-Smads传导通路,使Ⅰ型胶原分泌下调,有效抑制TGFβ诱导的肝纤维化。     

抗结缔组织生长因子特异性小干扰RNA的设计、合成及筛选

目的 设计和合成针对抗肝纤维化关键基因抗结缔组织生长因子（connective tissue growth factor,CTGF）的特异性小干扰RNA（siRNA）,并筛选高效的CTGF siRNA抗肝纤维化序列.方法 参照siRNA设计原则,应用RNA在线设计软件,设计3段RNA干扰候选序列,分别转染正常干细胞株（L-02）,以转染非特异性siRNA（与CTGF mRNA无同源性）作为对照,应用Western 印迹检测L-02细胞CTGF蛋白质表达.结果 与对照相比,转染siRNA的L-02细胞CTGF蛋白表达明显下调,且siCTGF-1、siCTGF-2、siCTGF-3各片段干扰率分别为44.91 %、93.99 %、81.34%,其中以siCTGF-2干扰率最高,效果最明显.转染非特异性siRNA的L-02细胞CTGF蛋白表达无明显变化（P＜0.05）.结论 不同的CTGF siRNA对L-02细胞CTGF表达水平具有不同的干扰效能,成功合成能高效阻抑CTGF表达的CTGF siRNA,为进一步探索更特异、更有效的抗肝纤维化基因治疗这一新途径打下坚实基础.     

牛磺酸上调基因1(TUG1)对肝纤维化的作用及其机制*

目的:探讨牛磺酸上调基因1(TUG1)在肝纤维化中的作用机制。方法:按照文献建立TGF-β1(5 ng/ml)刺激的活化肝星状细胞模型和经典的1%DMN(1 ml/kg/d)致大鼠肝纤维化模型,将肝纤维化大鼠和活化肝星状细胞(HSC)均分为模型对照组、阴性对照组(沉默TUG1阴性对照)、siRNA干扰组(TUG1基因沉默组)。实验结束后利用苏木精-伊红(HE)染色检测大鼠肝脏组织病理变化;采用逆转录-聚合酶链反应(RT-PCR)法、蛋白免疫印记(Western blot)分别测定大鼠肝组织及活化肝星状细胞中α-平滑肌肌动蛋白(α-SMA)、TUG1、I型胶原蛋白(collagenI)、基质金属蛋白酶-2(MMP-2)、金属蛋白酶组织抑制因子(TIMP-1)、Smad2、Smad3表达水平。结果:肝组织病理学检查显示,沉默TUG1能够明显缓解肝脏纤维化病理改变,Western blot结果显示,沉默TUG1能够显著降低大鼠肝组织和活化肝星状细胞中TUG1、α-SMA、collagenI、MMP-2、TIMP-1、Smad2、Smad3基因与蛋白表达水平(P＜0.05)。与模型对照组相比,阴性对照组的TUG1、α-SMA的蛋白与基因水平明显升高(P＜0.05)。与模型对照组和阴性对照组相比,siRNA干扰组中TUG1, α-SMA, collagenI, MMP-2, TIMP-1, Smad2 and Smad3的蛋白和基因水平显著降低(P＜0.05),而在模型对照组和阴性对照组中TUG1, α-SMA, collagenI, MMP-2, TIMP-1, Smad2 and Smad3的蛋白和基因表达水平之间差异无显著性。结论:TUG1在肝纤维化组织和活化的肝星状细胞中显著上调,沉默TUG1可能通过抑制转化生长因子-β1(TGF-β1)/Smad信号通路改善1%DMN致大鼠肝纤维化病理损伤,降低活化肝星状细胞中纤维化相关蛋白水平,发挥抗肝纤维化的作用。     

异甘草酸镁对纤维化大鼠肝脏TGF-β 1及Smad蛋白表达的影响

目的：观察异甘草酸镁对四氯化碳诱导的肝纤维化大鼠肝脏组织TGF-β1及Smad蛋白表达的影响,以期揭示其抗纤维化的机制。方法：利用腹腔注射四氯化碳（CCl4）建立大鼠肝纤维化模型,然后应用不同剂量的异甘草酸镁和INF-γ处理,于实验第16周末检测大鼠血清透明质酸（HA）、层粘连蛋白（LN）、III型前胶原（PC-III）、IV型胶原（C-IV）的水平,采用RT-PCR法检测TGF-β1,Smad3,Smad7mRNA的表达。结果：与模型组比较,异甘草酸镁各剂量组血清HA,LN,PC-III,C-IV水平显著下降（P〈0.05）,肝脏TGF-β1、smad3的表达明显降低（P〈0.05）,smad7则有所上升。结论：异甘草酸镁可以改善肝纤维化大鼠肝组织纤维化程度,其作用机理与抑制TGF-β1、Smad3mRNA的表达,上调Smad7mRNA的表达有密切关系。     

川芎嗪对转化生长因子β1刺激肝星状细胞CTGF及I型胶原表达的影响

研究川芎嗪对大鼠肝星状细胞株（hepatic stellate cell—T6,HSC—T6）结缔组织生长因子CTGF（connec tivetissue growth factor）及I型胶原表达的影响．培养HSC—T6细胞,不同浓度川芎嗪与转化生长因子-β1（transforming growth factor-β1,TGF-βl）刺激的HSC—T6共同孵育．用MTT（3-（4,5-Dimethyhhiazol-2-yl）-2,5-diphenyltetrazolium bromide）法检测HSC-T6增殖：免疫细胞化学法观察川芎嗪对CTGF表达的影响;Western印迹法检测CTGF蛋白的表达．ELISA（enzyme linked immunosorbent assay）法测定I型胶原表达．结果表明,一定浓度（100、200、400、600mg／L）川芎嗪能抑制HSC—T6增殖,且呈剂量依赖性．免疫细胞化学结果显示随着川芎嗪浓度的升高,CTGF表达依次递减,与正常对照纽比较,具有显著性差异（t=4．216,P〈0．01）．川芎嗪还可以明显抑制CTGF蛋白的表达,并可抑制I型胶原合成,二者抑制程度呈正相关关系（r=0．861,P〈0．01）．川芎嗪可能通过抑制HSC—T6细胞增殖,下调CTGF的表达,阻断I型胶原合成,从而发挥其抗肝纤维化的作用．     

小干扰RNA沉默瘦素揭示了瘦素在大鼠肝纤维化中的作用

目的观察靶向瘦素(leptin)小干扰RNA(interference,siRNA)真核细胞表达质粒对大鼠肝纤维化的影响。方法采用已构建的重组Leptin-siRNA真核细胞表达质粒,用脂质体包埋法通过腹腔注射将其导入大鼠肝纤维化模型体内。通过HE染色观察肝脏病理形态学变化;Western Blot检测leptin、I型胶原和STAT3蛋白表达变化;半定量RT-PCR检测leptin mRNA表达。结果与正常对照组相比,肝纤维化组(CCl4)和质粒空载体组(CCl4(+)K)肝纤维化程度较重,纤维化评分多为Ⅳ级(P0.01),同时肝脏leptin、I型胶原和STAT3含量明显上升(P0.05);而与肝纤维化组(CCl4)和质粒空载体组(CCl4(+)K)比,leptin-siRNA质粒转染组(The CCl4(+)L)肝纤维化程度减轻,纤维化程度多为Ⅰ-Ⅱ级,肝脏leptin、I型胶原和STAT3表达均显著抑制(P0.05)。正常对照组和leptin-siRNA质粒组(The CCl4(+)L)在组织学及leptin、I型胶原和STAT3基因转录和表达水平无统计学差异(P0.05)。结论 leptin-siRNA表达质粒降低I型胶原和STAT3含量、抑制leptin表达,阻抑肝纤维化;Leptin有望成为肝纤维化基因治疗的新靶位点。     

靶向survivin的siRNA联合5-Fu转染抑制肝细胞株HepG2增殖的研究

目的：研究靶向survivin的（小分子干扰RNA）siRNA和（氟尿嘧啶）5-FU联用对肝癌细胞HepG2的增殖抑制及凋亡的影响。方法：将HepG2细胞分为空白对照组、阴性对照组、5-FU处理组、siRNA转染组、5-FU＋siRNA转染组。转染采用脂质体法。RT-PCR法检测HepG2细胞survivinmRNA转录水平;MTT法检测靶向survivin的siRNA和5．FU对HepG2细胞增殖的抑制作用;流式细胞术检测HepG2细胞凋亡情况。结果：空白对照组、阴性对照组、5-FU处理组survivinmRNA表达无明显变化（P〉0．05）,siRNA转染组、5-FU＋siRNA转染组survivinmRNA表达明显下降（F=280．326,q=4．72-7．34,P〈0．05）。5-FU＋siRNA转染组增殖抑制率为51．58％±1-35％,与其它各组相比抑制率明显增高（F=280．326,q=5．27-9．84,P〈0．05）。5-Fu＋siRNA组与其它各组相比细胞凋亡率明显增高（F=13568．68,q=110．47-327．16,P〈0．01）。结论：将靶向survivin的siRNA和5一Fu联合应用可以显著抑制肝癌细胞survivin基因表达,并协同抑制HepG2细胞增殖,共同发挥诱导细胞凋亡作用。     

miR-101a在乙型肝炎病毒相关性肝纤维化患者中的表达及对肝星状细胞的影响

摘要 目的：探究miR-101a在乙型肝炎病毒（HBV）相关性肝纤维化患者中的表达及对肝星状细胞（HSC）的影响。方法：根据肝纤维化程度将HBV相关性肝纤维化患者进行分组（S0组、S1组、S2组、S3组和S4组）,健康受试者作为健康对照组。通过RT-PCR检测肺组织中miR-101a的表达,并分析miR-101a与疾病严重程度的关系。使用重组人TGF-β1处理人肝星状细胞系LX-2,并对LX-2细胞转染阴性对照 miRNA模拟物（NC-mimic组）、miR-101a模拟物（miR-101a-mimic组）、阴性对照 miRNA抑制剂（NC-inhibitor组）或miR-101a抑制剂（miR-101a-inhibitor组）,未转染的细胞作为对照组,然后通过RT-PCR或蛋白质印迹检测激活HSC及ECM产生的关键基因（α-SMA、COL1A1、COL1A2和COL3A1）和蛋白（a-SMA、collagen I和collagen III）的表达水平。将SD大鼠随机分为4组：对照组、CCl4组、Ad-control组和Ad-miR-101a组,对大鼠腹腔注射CCl₄（1 mL/kg体重）诱导肝纤维化模型,每周3次,共4周。然后将5×10⁹感染单位的携带miR-101a的重组腺病毒（Ad-miR-101a）或对照腺病毒（Ad-control）经尾静脉注射到大鼠中。4周后,通过苏木精和伊红（H＆E）和Masson三色染色评估肝脏形态和纤维化,通过免疫组化染色评估肝脏α-SMA、E-cadherin、vimentin、Smad4或p-Smad2/3的表达。结果：与健康受试者相比,HBV相关肝纤维化患者肝组织中miR-101a的表达水平明显降低,并且miR-101a的表达水平随着患者的严重程度升高而降低（P<0.05）。与未处理的细胞相比,miR-101a在TGF-β1处理的LX-2细胞中以浓度和时间依赖性方式显著下降（P<0.05）。与未处理的细胞相比,5 ng/mL TGF-β1处理LX-2细胞中的α-SMA、COL1A1、COL1A2和COL3A1 mRNA表达水平及a-SMA、collagen I和collagen III 蛋白表达水平均显著升高（P<0.05）。与对照组相比,miR-101a-mimic组的α-SMA、COL1A1、COL1A2、COL3A1和TGF-β1 mRNA和a-SMA、collagen I、collagen III、TGF-β1、Smad3和p-Smad3蛋白表达均下调（P<0.05）。与对照组相比,Ad-miR-101a组大鼠肝组织中E-cadherin的表达上调,但α-SMA、vimentin、Smad4和p-Smad2/3的表达下调（P<0.05）;Ad-miR-101a组大鼠的肝组织形态基本恢复正常,肝组织纤维化程度低于CCl₄组。结论：miR-101a水平与乙型肝炎病毒相关性肝纤维化严重程度相关,上调miR-101a可能通过抑制HSC的活化及上皮间质转化发挥抗纤维化作用。     

利用RNA干扰抑制人肝癌细胞中核因子-κB p65基因的表达

目的：用小干扰RNA（siRNA）抑制核因子-κB（NF-κB）p65基因在人肝细胞癌细胞中的表达。方法：从p65的cDNA序列中挑选3个RNA干扰靶位点,用体外转录法制备siRNA,以萤光素酶基因的siRNA为对照,分别转染Hep3B和SMMC-7721细胞,用逆转录半定量PCR和免疫印迹检测siRNA对p65基因表达的抑制效率。结果：3条siRNA对p65基因的表达都有抑制作用,其中2条siRNA的抑制作用更为显著,最高抑制效率约为70%。结论：制备的p65-siRNA可用于研究NF-κB在肝细胞癌发生发展中的作用。     

小干扰RNA靶向EGFR基因逆转卵巢癌细胞顺铂耐药的研究

目的：探讨载体表达的小干扰RNA（siRNA）影响卵巢癌耐药细胞株EGFR基因的表达并逆转其顺铂耐药的可行性。方法：体外构建EGFR小发卡状RNA（shRNA）的表达质粒,脂质体法介导将其转染入SKOV3/DDP细胞。实验分为正常对照组、空质粒转染组、非特异性转染组和特异性转染组。采用逆转录聚合酶链反应（RT-PCR）检测EGFR mRNA的表达;使用免疫细胞化学法（ICC）检测EGFR蛋白的表达;使用四甲基偶氮唑蓝法（MTT）测定各组细胞对顺铂的半数抑制浓度（IC50）。结果：EGFR shRNA转染组细胞EGFR mRNA的表达与其他两组相比明显减弱（P〈0.01）,EGFR蛋白表达明显下调（P〈0.01）;顺铂敏感性比正常对照组提高了约2.5倍。结论：针对EGFR合成的siRNA能够有效地抑制EGFR mRNA和蛋白的表达,并能恢复其对顺铂的敏感性。应用RNAi技术,能够逆转卵巢癌细胞对化疗药物的耐药性。     

Sulforaphane attenuates hepatic fibrosis via NF-E2-related factor 2-mediated inhibition of transforming growth factor-β/Smad signaling

Sulforaphane (SFN) is a dietary isothiocyanate that exerts chemopreventive effects via NF-E2-related factor 2 (Nrf2)-mediated induction of antioxidant/phase II enzymes, such as heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1). This work was undertaken to evaluate the effects of SFN on hepatic fibrosis and profibrotic transforming growth factor (TGF)-β/Smad signaling, which are closely associated with oxidative stress. SFN suppressed TGF-β-enhanced expression of α-smooth muscle actin (α-SMA), a marker of hepatic stellate cell (HSC) activation, and profibrogenic genes such as type I collagen, fibronectin, tissue inhibitor of matrix metalloproteinase (TIMP)-1, and plasminogen activator inhibitor (PAI)-1 in hTERT, an immortalized human HSC line. SFN inhibited TGF-β-stimulated activity of a PAI-1 promoter construct and (CAGA)(9) MLP-Luc, an artificial Smad3/4-specific reporter, in addition to reducing phosphorylation and nuclear translocation of Smad3. Nrf2 overexpression was sufficient to inhibit the TGF-β/Smad signaling and PAI-1 expression. Conversely, knockdown of Nrf2, but not inhibition of HO-1 or NQO1 activity, significantly abolished the inhibitory effect of SFN on (CAGA)(9) MLP-Luc activity. However, inhibition of NQO1 activity reversed repression of TGF-β-stimulated expression of type I collagen by SFN, suggesting the involvement of antioxidant activity of SFN in the suppression of Smad-independent fibrogenic gene expression. Finally, SFN treatment attenuated the development and progression of early stage hepatic fibrosis induced by bile duct ligation in mice, accompanied by reduced expression of type I collagen and α-SMA. Collectively, these results show that SFN elicits an antifibrotic effect on hepatic fibrosis through Nrf2-mediated inhibition of the TGF-β/Smad signaling and subsequent suppression of HSC activation and fibrogenic gene expression.     

The antifibrotic effects of TGF-β1 siRNA on hepatic fibrosis in rats

Background/aims: Hepatic fibrosis results from the excessive secretion of matrix proteins by hepatic stellate cells (HSCs), which proliferate during fibrotic liver injury. Transforming growth factor (TGF)-β1 is the dominant stimulus for extracellular matrix (ECM) production by stellate cells. Our study was designed to investigate the antifibrotic effects of using short interference RNA (siRNA) to target TGF-β1 in hepatic fibrosis and its mechanism in rats exposed to a high-fat diet and carbon tetrachloride (CCL4). Methods: A total of 40 healthy, male SD (Sprague–Dawley) rats were randomly divided into five even groups containing of eight rats each: normal group, model group, TGF-β1 siRNA 0.125 mg/kg treatment group, TGF-β1 siRNA 0.25 mg/kg treatment group and TGF-β1 siRNA negative control group (0.25 mg/kg). CCL4 and a high-fat diet were used for 8 weeks to induce hepatic fibrosis. All the rats were then sacrificed to collect liver tissue samples. A portion of the liver samples were soaked in formalin for Hematoxylin–Eosin staining, classifying the degree of liver fibrosis, and detecting the expression of type I and III collagen and TGF-β1; the remaining liver samples were stored in liquid nitrogen to be used for detecting TGF-β1 by Western blotting and for measuring the mRNA expression of type I and III collagen and TGF-β1 by quantitative real-time polymerase chain reaction. Results: Comparing the TGF-β1 siRNA 0.25 mg/kg treatment group to the model group, the TGF-β1 siRNA negative control group and the TGF-β1 siRNA 0.125 mg/kg treatment group showed significantly reduced levels of pathological changes, protein expression and the mRNA expression of TGF-β1, type I collagen and type III collagen (P < 0.01). Conclusions: Using siRNA to target TGF-β1 can inhibit the expression of TGF-β1 and attenuate rat hepatic fibrosis induced by a high-fat diet and CCL4. A possible mechanism is through the down-regulation of TGF-β1 expression, which could inhibit HSC activation, as well as the proliferation and collagen production of collagen reducing, so that collagen deposition in the liver is reduced.     

Decursin attenuates hepatic fibrogenesis through interrupting TGF-beta-mediated NAD(P)H oxidase activation and Smad signaling in vivo and in vitro

Aims

We studied that a potent antifibrotic effect of decursin on in vivo liver damage model and the mechanism in inhibiting which transforming growth factor (TGF)-β1-induced human hepatic stellate cells (HSCs) activation.

Main methods

Liver injury was induced in vivo by intraperitoneal injection of carbon tetrachloride (CCl₄) with or without decursin for 4 weeks in mice. Human hepatic stellate cell line, an immortalized human HSC line, was used in in vitro assay system. The effects of decursin on HSC activation were measured by analyzing the expression of α-smooth muscle actin (α-SMA) and collagen I in liver tissue and human HSCs.

Key findings

Decursin treatment significantly reduced the ratio of liver/body weight, α-SMA activation, and type I collagen overexpression in CCl₄ treated mice liver. The elevated serum levels, including ALT, AST, and ALP, were also decreased by decursin treatment. Treatment of decursin markedly proved the generation of reactive oxygen species, NAD(P)H oxidase (NOX) protein (1, 2, and 4) upregulation, NOX activity, and superoxide anion production in HSCs by TGF-β1. It also significantly reduced TGF-β1-induced Smad 2/3 phosphorylation, nuclear translocation of Smad 4, and association of Smad 2/3–Smad 4 complex. Consistent with in vitro results, decursin treatment effectively blocked the levels of NOX protein, and Smad 2/3 phosphorylation in injured mice liver.

Significance

Decursin blocked CCl₄-induced liver fibrosis and inhibited TGF-β1-mediated HSC activation in vitro. These data demonstrated that decursin exhibited hepatoprotective effects on experimental fibrosis, potentially by inhibiting the TGF-β1 induced NOX activation and Smad signaling.     

血管平滑肌细胞中ERK通路与TGF-β_1/Smad通路的相互作用

目的:探讨血管平滑肌细胞(VSMC)中TGF-β/Smad与ERK信号转导通路是否存在相互调节关系。方法:原代培养的大鼠胸主动脉平滑肌细胞,分四组:①对照组,②TGF-β1组,③ERK阻断剂(PD98059)组和④TGF-β1+ERK阻断剂(PD98059)组。分别用Western blot法检测VSMC内Smad2/3、ERK1/2蛋白表达及磷酸化Smad2/3、磷酸化ERK1/2蛋白含量,RT-PCR方法测VSMC中Smad2、Smad3mRNA的表达。结果:①与对照组相比,TGF-β1组P-Smad2/3、P-ERK1/2蛋白含量增多(P0.05),ERK阻断剂组P-Smad2/3、P-ERK1/2蛋白含量减少(P0.05),TGF-β1+ERK阻断剂组P-Smad2/3、P-ERK1/2蛋白含量无差异;与TGF-β1组相比,TGF-β1+ERK阻断剂组P-Smad2/3、P-ERK1/2蛋白含量减少(P0.05)。各组间Smad2/3、ERK1/2蛋白表达无差异。②各组的Smad2、Smad3mRNA表达无差异。结论:TGF-β1诱导的Smad2/3蛋白磷酸化依赖ERK通路激活,但ERK通路对Smad2/3蛋白和mRNA表达水平无影响。     

Effects of rhDecorin on TGF-β1 induced human hepatic stellate cells LX-2 activation

Decorin is a small leucine-rich extracellular matrix proteoglycan composed of a core protein with a single glycosaminoglycan (GAG) chain near the N-terminus and N-glycosylated at three potential sites. Decorin is involved in the regulation of formation and organization of collagen fibrils, modulation of the activity of growth factors such as transforming growth factor β (TGF-β), and exerts other effects on cell proliferation and behavior. Increasing evidences show that decorin plays an important role in fibrogenesis by regulating TGF-β, a key stimulator of fibrosis, and by directly modulating the degradation of extracellular matrix (ECM) from activated hepatic stellate cells (HSCs). In this study, the core protein of human decorin was cloned and expressed in Escherichia coli. The purified recombinant human decorin (rhDecorin) significantly inhibited the proliferation of LX-2 cells, a human HSC cell line, stimulated by TGF-β1. RT-PCR result showed that the expression of metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were reduced by rhDecorin in LX-2 cells stimulated by TGF-β1. Furthermore, the protein expression of smooth muscle-α-actin (α-SMA), collagen type III and phosphorylated Smad2 (p-Smad2) was significantly decreased in the presence of rhDecorin. rhDecorin also reduced fibrillogenesis of collagen type I in a dose-dependent manner. Gene expression profiles of LX-2 cells stimulated by TGF-β1 in the presence and the absence of rhDecorin were obtained by using cDNA microarray technique and differentially expressed genes were identified to provide further insight into the molecular action mechanism of decorin on LX-2 cells.     

Periostin down‐regulation attenuates the pro‐fibrogenic response of hepatic stellate cells induced by TGF‐β1

Liver fibrosis is characterized by an exacerbated accumulation of deposition of the extracellular matrix (ECM), and the activation of hepatic stellate cells (HSC) plays a pivotal role in the development of liver fibrosis. Periostin has been shown to regulate cell adhesion, proliferation, migration and apoptosis; however, the involvement of periostin and its role in transforming growth factor (TGF)‐β1‐induced HSC activation remains unclear. We used RT‐PCR and Western blot to evaluate the expression level of periostin in hepatic fibrosis tissues and HSCs, respectively. Cell proliferation was determined using the Cell Proliferation ELISA BrdU kit, cell cycle was analysed by flow cytometry. The expression of α‐smooth muscle actin (α‐SMA), collagen I, TGF‐β1, p‐Smad2 and p‐Smad3 were determined by western blot. Our study found that periostin was up‐regulated in liver fibrotic tissues and activated HSCs. In addition, siRNA‐periostin suppressed TGF‐β1‐induced HSC proliferation. The HSC transfected with siRNA‐periostin significantly inhibited TGF‐β1‐induced expression levels of α‐SMA and collagen I. Furthermore, TGF‐β1 stimulated the expression of periostin, and siRNA‐periostin attenuated TGF‐β1‐induced Smad2/3 activation in HSCs. These results suggest that periostin may function as a novel regulator to modulate HSC activation, potentially by promoting the TGF‐β1/Smad signalling pathway, and propose a strategy to target periostin for the treatment of liver fibrosis.     

Embryonic liver fodrin involved in hepatic stellate cell activation and formation of regenerative nodule in liver cirrhosis

Transforming growth factor (TGF) β(1) plays a critical role in liver fibrosis. Previous studies demonstrated embryonic liver fodrin (ELF), a β-spectrin was involved in TGF-β/Smad signalling pathway as Smad3/4 adaptor. Here we investigate the role of ELF in pathogenesis of liver cirrhosis. In carbon tetrachloride (CCl(4))-induced mice model of liver cirrhosis, ELF is up-regulated in activated hepatic stellate cells (HSCs), and down-regulated in regenerative hepatocytes of cirrhotic nodules. In activated HSCs in vitro, reduction of ELF expression mediated by siRNA leads to the inhibition of HSC activation and procollagen I expression. BrdU assay demonstrates that down-regulation of ELF expression does not inhibit proliferation of activated HSCs in vitro. Immunostaining of cytokeratin 19 and Ki67 indicates that regenerative hepatocytes in cirrhotic liver are derived from hepatic progenitor cells (HPC). Further study reveals that HPC expansion occurs as an initial phase, before the reduction of ELF expression in regenerative hepatocytes. Regenerative hepatocytes in cirrhotic liver show the change in proliferative activity and expression pattern of proteins involved in G1/S transition, which suggests the deregulation of cell cycle in regenerative hepatocytes. Finally, we find that ELF participates in TGF-β/Smad signal in activated HSCs and hepatocytes through regulating the localization of Smad3/4. These data reveal that ELF is involved in HSC activation and the formation of regenerative nodules derived from HPC in cirrhotic liver.