牛磺酸上调基因1(TUG1)对肝纤维化的作用及其机制

Effects of TUG1 on hepatic fibrosis and its mechanism

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。

Objective:To investigate the effects and mechanisms of taurine up-regulated gene 1(TUG1)in hepatic fibrosis.Methods:According to the literature,the classic hepatic fibrosis model of rats induced by 1%DMN(1ml/kg/d)was established.The rats with hepatic fibrosis and activated hepatic stellate cells(HSC)were divided into model control group,negative control group(transfected with siRNA negative control),siRNA interference group(transfected with TUG1).At the end of the experiment,hematoxylin eosin(HE)staining was used to detect the pathological changes of liver tissue;reverse transcription polymerase chain reaction(RT-PCR)and Western blot were used to determine the expression levels ofα-smooth muscle actin(α-SMA),TUG1,collagen I,matrix metalloproteinase-2(MMP-2),tissue inhibitor of metalloproteinase-1(TIMP-1),Smad2 and Smad3 in rat liver tissue and activated hepatic stellate cells.Results:Compared with the model control group,the protein and gene levels of TUG1 andα-SMA in the negative control group were increased significantly(P<0.05).The protein and gene levels of TUG1,α-SMA,collagen I,MMP-2,TIMP-1,Smad2 and Smad3 in the liver tissue and activated hepatic stellate cells in the siRNA interference group were decreased(P<0.05)while compared with the blank control group and the negative control group.There were no significant differences in the levels of TUG1,α-SMA,collagen I,MMP-2,TIMP-1,Smad2 and Smad3 in the liver tissue and activated hepatic stellate cells between the control group and the negative control group(P>0.05).Conclusion:TUG1 level is elevated in hepatic fibrosis tissue and activated hepatic stellate cells.Silencing TUG1 may improve the pathological damage of hepatic fibrosis induced by 1%DMN by inhibiting the transforming growth factor(TGF-β1)/Smad signaling pathway.