Caveolin-1在TGF-β1诱导人支气管上皮细胞间质化中的作用

Effect of caveolin-1 on TGF-β1-induced epithelial-mesenchymal transition of human bronchial epithelial cells

目的:探究小窝蛋白1(caveolin-1)在转化生长因子β1(TGF-β1)诱导的人支气管上皮细胞(16HBE细胞)上皮-间充质转化(EMT)中的作用。方法:以16HBE细胞株为研究对象,免疫荧光、RT-q PCR和Western blot实验检测16HBE细胞EMT过程中caveolin-1的mRNA和蛋白表达;Western blot检测siRNA干扰caveolin-1对16HBE细胞EMT的影响。结果:Caveolin-1广泛存在于16HBE细胞膜上,TGF-β1刺激后,caveolin-1的mRNA和蛋白表达减少(P<0.05)。与TGF-β1组比较,caveolin-1 siRNA和TGF-β1共同作用促进了细胞形态的转化,抑制了E-钙黏蛋白的蛋白表达而促进了α-SMA的蛋白表达(P<0.05)。TGF-β1刺激16HBE细胞后,AKT和Smad3在30 min磷酸化水平最高,与0 min对照组比较显著增加(P<0.05);用siRNA干扰caveolin-1基因后再用TGF-β1刺激16HBE细胞30 min,下游信号蛋白分子AKT和Smad3的磷酸化水平增高,与TGF-β1组比较显著增加(P<0.05)。结论:TGF-β1能下调16HBE细胞的caveolin-1表达水平;caveolin-1可能参与了TGF-β1诱导的16HBE细胞EMT过程中TGF-β1/Smad通路和PI3K-AKT通路的活化。

AIM: To investigate the role of caveolin-1 on epithelial-mesenchymal transition( EMT) in human bronchial epithelial( HBE) cells induced by transforming growth factor beta 1( TGF-β1). METHODS: Immunofluorescence,real-time PCR and Western blot were applied to detect the mRNA and the protein expression of caveolin-1 in the16 HBE cells during EMT. The influence of siRNA-mediated silencing of caveolin-1 on EMT in the 16 HBE cells was detected by Western blot. RESULTS: Caveolin-1 was widely present on the cell membrane of the 16 HBE cells. The expression of caveolin-1 at mRNA and protein levels was significantly decreased in a time-dependent manner in the 16 HBE cells compared with control group( P < 0. 05) after stimulation with TGF-β1. The morphologic changes of the 16 HBE cells induced by TGF-β1 were promoted by caveolin-1 silencing compared with TGF-β1 group. The protein expression of E-cadherin andα-SMA induced by TGF-β1 was promoted by caveolin-1 silencing compared with TGF-β1 group( P < 0. 05). The phosphorylation levels of AKT and Smad3 were the highest at 30 min and increased significantly compared with control group( P <0. 05) after stimulated with TGF-β1. Treatment of the 16 HBE cells with TGF-β1 for 30 min after silencing caveolin-1 gene for 24 h significantly increased the phosphorylation levels of AKT and Smad3 compared with TGF-β1 group( P < 0. 05).CONCLUSION: TGF-β1 down-regulates the expression of caveolin-1 in the 16 HBE cells. Caveolin-1 may participate in TGF-β1/Smad pathway and PI3K-AKT pathway,which are the signal transduction pathways for TGF-β1 inducing EMT.