PICK1在肝纤维化中的表达变化及功能研究

目的：研究蛋白激酶 C 结合蛋白1（PICK1）在小鼠肝纤维及活化的肝星状细胞中的表达变化，并探讨其对人肝星状细胞株（LX-2）活化的影响。方法建立四氯化碳（CCl4）诱导的小鼠肝纤维化模型，观察 PICK1在肝纤维化过程中的表达变化；转化生长因子β1（TGF-β1）刺激 LX-2活化，West-ern blot 测定 PICK1的蛋白表达情况；转染 PICK1过表达质粒至 LX-2中，再以 TGF-β1诱导活化，Western blot 检测PICK1、α平滑肌肌动蛋白（α-SMA）、I 型胶原（Col1a1）和Smad2、3及其磷酸化水平的蛋白表达情况。结果正常组小鼠肝脏中 PICK1表达较高，随着肝纤维化的加重，PICK1的表达逐渐递减。TGF-β1诱导活化的 LX-2细胞中 PICK1表达降低。转染 PICK1过表达质粒后，TGF-β1诱导的α-SMA、Colla1的表达明显减少，且 Smad2、3磷酸化水平显著下降。结论 PICK1在纤维化肝组织及活化的 HSC 中表达下调。过表达 PICK1可抑制 TGF-β1诱导的 LX-2活化，可能是通过抑制 TGF-β／Smad 通路而发挥作用，为肝纤维化的防治研究提供了新的思路和靶点。

The expression and effect of PICK1 in liver fibrosis

Objective To explore the expression of protein interacting with Ca-kinase-1(PICK1)in fibrotic liver of mice and activated hepatic stellate cell,and investigate the effect of PICK1 on the activation of hepatic stellate cell strain (LX-2).Methods Liver fibrosis model in mice was induced by CCl4 and then the PICK1 level was detec-ted in fibrotic liver tissue.LX-2 cells were activated by transforming growth factor β1 (TGF-β1),and the protein level of PICK1 was detected by Western blot.After transfected with the plasmid expressing PICK1,LX-2 was stim-ulated with TGF-β1,the levels of α-smooth muscle actin(α-SMA),collagen type I (Col1a1 ),Smad2,3 and phosphorylation level of them were determined by Western blot.Results PICK1 was highly expressed in normal liver tissues and progressively down-regulated as liver fibrosis progressed.The expression of PICK1 was down-regu-lated in activated LX-2 induced by TGF-β1.The hepatic stellate cell transfected with PICK1-plasmid showed re-markablely decreased TGF-β1-induced α-SMA and Col1a1 expression and obviously declined phosphorylation levels of Smad2 and Smad3.Conclusion The expression of PICK1 decreases in fibrotic livers and activated hepatic stel-late cell.Over-expression of PICK1 can suppress the activation of hepatic stellate cell induced by TGF-β1,and probably because of the inhibitory effect on TGF-β/Smad pathway,which provides new ideas and targets for the prevention and treatment of liver fibrosis.