细胞因子信号抑制物7通过抑制肾小管上皮细胞转分化减轻肾脏纤维化

摘要

目的 探讨细胞因子信号抑制物7(SOCS7)在缺氧诱导的人肾小管上皮细胞间充质转分化(EMT)及肾间质纤维化中的相关作用机制.方法 缺氧处理人肾小管上皮细胞(HK2),采用实时聚合酶链反应(RT-PCR)检测不同时间SOCS7的mRNA表达变化.采用Western blot法检测SOCS7及相关纤维化因子 α-平滑肌肌动蛋白(α-SMA)、E-钙黏素(E-cadherin)及Ⅰ型胶原(COL1)的蛋白表达水平.转染SOCS7干扰质粒及正义质粒后,采用Western blot法检测相关纤维化因子的蛋白表达变化.采用Masson染色观察单侧输尿管梗阻(UUO)小鼠(UUO组)2周后肾间质纤维化程度,免疫组化染色观察SOCS7及相关纤维化因子表达.结果 与常氧组比较,缺氧处理后的HK2细胞SOCS7 mRNA表达下调,同时E-cadherin蛋白表达下调,α-SMA、COL1蛋白表达均上调.转染SOCS7干扰质粒后,E-cadherin蛋白表达下调,α-SMA、COL1蛋白表达均上调;转染SOCS7正义质粒后,结果则相反.与对照组比较,Masson染色结果显示,UUO组小鼠肾间质纤维化程度增高,SOCS7及E-cadherin蛋白表达量减少,α-SMA、COL1蛋白表达量增高.结论 在缺氧微环境下,通过上调SOCS7能够直接抑制HK2细胞的EMT进程,进而减轻肾间质纤维化.%Objective To investigate the effect and mechanism of the suppressor of cytokine signaling(SOCS)7 in human renal tubular epithelial-mesenchymal transition(EMT)and hypoxia-induced renal interstitial fibrosis.Methods In vitro,human kidney tubular epithelial cells were subjected to hypoxia,then the expression of SOCS7 in HK2 cells were detected by real time polymerase chain reaction (RT-PCR)at different times after hypoxia.The expression of SOCS7 and related fibrotic factors alpha smooth muscle actin(α-SMA),E-cadherin and collagen 1 (COL1 )were detected by Western blotting. Cultured HK-2 cells were transfected with SOCS7-siRNA and SOCS7-plasmid,and the expression levels ofα-SMA,E-cadherin and COL1 protein were detected by Western blotting.The unilateral urethral obstruction (UUO)mouse model was established,and the renal tissue fibrosis degree was observed by Masson staining after two weeks.The expression of SOCS7,α-SMA,E-cadherin and COL1 were detected by immuno-histochemical staining.Results Compared with normoxia group,hypoxia group showed a significant decrease of SOCS7 in HK2 cells,meanwhile hypoxia induced a significant decrease of E-cadherin and increase ofα-SMAand COL1 in protein level.After transfection of SOCS7-siRNA,the expression of E-cadherin protein decreased and the expression of α-SMA and COL1 increased.After transfection of SOCS7-plasmid,the results were opposite.Compared with the control group,Masson staining showed the increased degree of interstitial fibrosis and the increased expression of α-SMA and COL1 ,the decreased expression of SOCS7 and E-cadherin.Conclusion Under hypoxic microenviroment,overexpression of SOCS7 could directly suppress the EMT process in HK2 cells,and eventually alleviate renal interstitial fibrosis.