烟草烟雾通过TGF-β1/Smad2通路诱导RLE-6TN发生上皮间质转化

Cigarette smoke extract induce EMT of RLE-6TN cells via TGF-β1/Smad2 pathway

目的:探讨烟草烟雾提取物(Cigarette smoke extract,CSE)在诱导大鼠Ⅱ型肺泡上皮细胞RLE-6TN发生上皮间质转化(Epithelial-mesenchymal transition,EMT)中的作用及机制。方法:以不同浓度(0.25%,0.5%及1%)CSE刺激RLE-6TN细胞株;TGF-β1受体抑制子(SB431542)预处理后,加入1%CSE共培养。实时定量PCR(RT-PCR)检测E-cadherin和Vimentin RNA表达;印迹法(Western blot)检测TGF-β1、Smad2、磷酸化的Smad2(p-Smad2)、E-cadherin、N-cadherin和Vimentin蛋白的表达量。结果:经不同浓度的CSE作用,E-cadherin无论是在RNA还是在蛋白水平表达均下调,而Vimentin表达均上调;同时,TGF-β1、p-Smad2和N-cadherin蛋白表达量增加;TGF-β1受体抑制子(SB431542)干预后,p-Smad2表达量明显降低(P<0.05),E-cadherin蛋白表达量较对照组明显增加(P<0.05),N-cadherin和Vimentin蛋白表达量较对照组明显降低(P<0.05)。结论:CSE可能通过激活TGF-β1/Smad2信号通路,参与调节E-cadherin、N-cadherin和Vimentin蛋白的表达,从而诱导RLE-6TN发生EMT。

Objective： To investigate the effect of cigarette smoke extract（ CSE） induced EMT in rat alveolar type Ⅱ cells（ RLE-6TN）. Methods： The different concentrations of CSE co-cultured with RLE-6TN and inhibitor of the transforming growth factor-β1（ TGF-β1） typeⅠ receptor was administered prior to CSE exposure（ SB431542）. Expression levels of E-cadherin and Vimentin were examined by RT-PCR. The expression levels of TGF-β1,p-Smad2,Smad2,E-cadherin,N-cadherin and Vimentin were examined by Western blot. Results： Our results showed that the expression of E-cadherin decreased in CSE-treated group,while the expression of TGF-β1,p-Smad2,N-cadherin and Vimentin obviously increased after CSE exposure,however,which could be abrogated by SB431542. Conclusion： TGF-β1/Smad2 signal pathway may be involved in the CSE induced EMT in rat alveolar cells.