氯沙坦含药血清对肾小管上皮-间充质转分化的抑制作用

目的:肾小管上皮细胞-间充质转分化(epithelial-to-mesenchymal transition,EMT)是肾小管间质纤维化(tubulointerstitial fibrosis,TIF)的关键发病机制,而肾小管间质纤维化是慢性肾脏病进展为终末期肾病(end-stage renal dis-ease,ESRD)的重要共同通路。血管紧张素ⅡAT1受体阻断剂氯沙坦对于延缓慢性肾脏病进展有一定的作用,但其能否抑制肾小管上皮细胞-间充质转分化继而抑制肾间质纤维化尚不清楚。本实验通过体外TGF-β1诱导HK-2细胞向间充质细胞转分化,观察氯沙坦对肾小管上皮细胞-间充质转分化的抑制作用及其可能机制。方法:在体外使用TGF-β1诱导HK-2细胞表型改变并给予氯沙坦大鼠含药血清干预。氯沙坦大鼠含药血清按照既定的操作程序获取。HK-2细胞行E-cadher-in,Vimentin,β-catenin和ZEB1免疫荧光染色及Western blot分析。结果:TGF-β1诱导肾小管上皮细胞HK-2转化为间充质细胞,细胞形态由卵圆形变为长梭形,上皮标志物E-cadherin表达下调,间充质标志物Vimentin表达上调,上皮细胞-间充质转分化相关分子β-catenin在胞浆、胞核的积聚增多以及ZEB1表达增强;氯沙坦大鼠含药血清能够部分抑制TGF-β1诱导的HK-2转化为间充质表型,并维持HK-2细胞的上皮表型,抑制E-cadherin的表达下调和Vimentin的表达上调;同时抑制β-catenin在胞浆、胞核的积聚以及ZEB1的表达。结论:研究结果提示氯沙坦可抑制体外的肾小管上皮细胞-间充质转分化,其机制可能与氯沙坦抑制β-catenin/ZEB1通路有关。

Inhibitory Effect of Serum Containing Losartan on Tubular Epithelial-to-Mesenchymal Transition in Vitro

Objective:Tubular epithelial-to-mesenchymal transition(EMT) had been proven to be a critical step in the pathogenesis of tubulointerstitial fibrosis(TIF) and TIF had evolved as the important common process underlying the progression of chronic kidney disease(CKD) to end-stage renal disease(ESRD).Losartan,a classical type 1 Angiotensin II receptor blocker,had been demonstrated to delay the progression of chronic kidney disease,but whether it can inhibit the tubular EMT and TIF remain uncertain.Here we investigated the inhibitory effects of losartan on epithelial-to-mesenchymal transition and its possible mechanism in transforming growth factor(TGF)-β1-induced EMT of HK-2 cells in vitro.Methods:The phenotype changes of HK-2 cells were induced by TGF-β1 and interfered with rat serum containing losartan.Expression of E-cadherin,vimentin,β-catenin and ZEB1 in HK-2 cells was detected by immunofluorescence staining and Western blot.Results:Losartan inhibited the HK-2 cell myofibroblast phenotype induced by TGF-β1 and maintained the epithelial phenotype of HK-2 cells to some extent.Losartan inhibited downregulation of E-cadherin and upregulation of vimentin in HK-2 cells induced by TGF-β.Losartan also inhibited the localization of β-catenin in the cytoplasm and nucleus and suppressed upregulation of ZEB1 in HK-2 cells induced by TGF-β1.Conclusion:These results suggest that losartan prevents tubular EMT in vitro,possibly by inhibiting the β-catenin/ZEB1 pathway.