β-连环素酪氨酸磷酸化调控E-钙黏蛋白表达参与转化生长因子β1诱导的人肾小管上皮细胞转分化  

Tyrosine phosphorylation ofβ-catenin modulates the expression of E-cadherin involved in the epithelial-mesenchymal transition induced by TGF-β1

作　　者：韩敏[1] 徐钢[1] 曾锐[1] 刘蔚[1] 

机构地区：[1]华中科技大学同济医学院同济医院肾内科,武汉430030

出　　处：《中华肾脏病杂志》2006年第8期494-498,共5页Chinese Journal of Nephrology

基　　金：国家自然科学基金(30370657);教育部新世纪优秀人才支持计划(NCET-04-0712);湖北省自然科学基金(2006ABB022)

摘　　要：目的观察β-连环素(catenin)在TGF-β1诱导的上皮细胞-间充质细胞转分化(EMT)过程中对E-钙黏蛋白(cadherin)表达的调控作用。方法应用穿透性多肽技术构建表达底物模仿多肽和对照多肽。以体外培养的人肾小管上皮细胞HK2为研究对象,模型组予10 ng／ml TGF-β1刺激肾小管上皮细胞72 h,底物模仿多肽组和对照多肽组同时分别予2μmol／L的底物模仿多肽或对照多肽干预TGF-β1刺激肾小管上皮细胞:应用Western印迹方法检测各组E-cadherin、α-SMA蛋白的表达及各组β-catenin酪氨酸磷酸化水平。应用激光共聚焦显微镜观察各组细胞β-catenin的分布。结果正常对照组表达E-cadherin,几乎不表达α-SMA,β-catenin酪氨酸磷酸化水平低,主要表达于细胞连接间的细胞膜上。模型组几乎不表达E-cadherin,α-SMA的表达上调,β-catenin酪氨酸磷酸化水平上调,主要表达于细胞核内。底物模仿多肽组与正常组的结果相似;对照多肽组与模型组结果相似。结论人肾小管上皮细胞β-catenin酪氨酸磷酸化水平的上调,使β-catenin向核转移,E-cadherin／β-catenin复合体解离,E-cadherin功能丧失,表达α-SMA,参与TGF-β1诱导的EMT。Objeαive To observe the regulatory mechanism of β-catenin in modulating the expression of E-cadherin in TGF-β1 induced epithelial-mesenchymal transition （EMT）. Methods The substrate mimetic peptide and control peptide were construαed. The human tubular cells （HK2 cell hne） were cultured with 10 ng/ml TGF-β1 for 72 hours, in the group of the substrate-analogue peptide and control peptide the cells were incubated with 2 μmol/l peptide and 10ng/ml TGF-β1 for 72 hours. The expression of E-cadherin and α-SMA was measured by Western blot. Tyrnsine phosphorylation of β-catenin was measured by Western blot as well.The intracellular disposition of β- catenin was observed by confocal microscope. Results In the normal HK-2 cells, E-cadherin was expressed, α-SMA was almost not expressed, and β-catenin in the state of dephosphorylation was mainly expressed on the membrane of the cell.In the model group, E-cadherin was not expressed, the expression of α-SMA was up-regulated, and tyrnsine of β-catenin was phosphorylated and located in the cell nucleus.The experimental results of the cells of the substrate mimetic peptide group was similar to those of the normal group, so do the results of the cells of the control peptide group and the model group. Conclusions In the human tubular cells, the up-regulation of tyrnsine phosphorylation of β-catenin, followed by β-catenin moving from cell membrane to the cell nucleus leads to the disassociation of the complex of E-cadherin/β-catenin, which is involved in the loss of E-cadherin , expression of α-SMA and EMT induced by TGF-β1.

关 键 词：转化生长因子β Β-连环素 钙黏糖蛋白类 酪氨酸磷酸化 

分 类 号：R692[医药卫生—泌尿科学]