TGF-β1/Smad2通路参与IL-17诱导的A549细胞上皮-间质转化

TGF-Beta1/Smad2 Pathway Is Involved in the Epithelial-Mesenchymal Transition Induced by Interleukin-17 in A549 Cells

目的:探讨白细胞介素(IL)-17对A549细胞上皮-间质转化的影响及TGF-β1/Smad2信号通路在其中的作用。方法:用不同浓度(0,10,25,50,100ng/ml)IL-17刺激A549细胞48h,RT-PCR检测E-钙黏蛋白(E-cad)、α-平滑肌肌动蛋白(SMA)、TGF-β1的表达。将体外培养的细胞分为3组:对照组、IL-17(100ng/ml)组、IL-17+SB431542组。48h后收集各组细胞,RT-PCR和Western Blot检测E-cad、α-SMA、TGF-β1、Smad2、和p-Smad2的表达。结果:不同浓度的IL-17作用后,E-cad在50ng/ml IL-17组时表达下调,与浓度呈负相关;α-SMA在100ng/ml IL-17组时表达上调;TGF-β1在25ng/ml IL-17组时表达上调,与浓度呈正相关。与对照组相比,IL-17组E-cad表达下调,α-SMA、TGF-β1、p-Smad2表达均增加,Smad2蛋白表达水平无明显变化;与IL-17组比较,IL-17+SB431542组Smad2蛋白表达水平无明显变化,TGF-β1、p-Smad2、α-SMA蛋白表达均降低,E-cad的表达明显增加。结论:TGF-β1/Smad2通路参与IL-17诱导的A549细胞上皮-间质转化。

Objective：To investigate the effect of interleukin 17（IL-17）on epithelial-mesenchymal transition of A549 cells and the role of TGF-β1/Smad2 signaling pathway in the process.Methods：Human alveolar epithelial（A549）cells were cultured in vitro and stimulated with different concentrations（0,10,25,50,100ng/ml）of IL-17 for 48h,the expression of E-cadherin（E-cad,an epithelial marker）,α-smooth muscle actin（α-SMA,a mesenchymal marker）and TGF-β1were detected by RT-PCR.Then,A549 cells were randomly divided into three groups：control group,IL-17group（treated by IL-17 with 100ng/ml）and IL-17＋ SB431542 group.After given the corresponding processing,cells were collected after 48 hours and the expressions of E-cad,α-SMA,TGF-β1,p-Smad2 and Smad2were evaluated by quantitative RT-PCR and Western Blot.Results：The expression of E-cad was down-regulated from 50ng/ml IL-17 treatment,which negatively correlated with concentrations.α-SMA was up-regulated in 100ng/ml of IL-17 group and TGF-β1was also up-regulated from 25ng/ml of IL-17 with a positive correlation with concentra-tions.Compared with the control group,the expression of E-cad was significantly decreased,α-SMA,TGF-β1and p-Smad2 expressions were obviously increased after IL-17 exposure,while the expression of Smad2 did not show significant difference.Compared with the IL-17 group,the expression levels of TGF-β1,p-Smad2 andα-SMA were markedly decreased and E-cad was significantly increased after a selective inhibitor of TβRI kinases-SB431542 was added,whereas the expression of Smad2 was not significantly different.Conclusion：TGF-β1/Smad2 signaling pathway may be involved in the epithelial-mesenchymal transition induced by interleukin-17 in A549 cells.