肺泡上皮细胞间质转化及其信号转导途径在肺纤维化中的作用  

The role of epithelial-mesenchymal transition of alveolar epithelial cells and its signalling pathways in pulmonary fibrosis

作　　者：黄振杰[1] 郑金旭[2] 汤艳[2] 曾彤华[1] 蔡文华[1] 李斐[1] 

机构地区：[1]北海市人民医院呼吸科,广西北海536000 [2]江苏大学附属医院呼吸科,江苏镇江212001

出　　处：《临床肺科杂志》2011年第6期823-826,共4页Journal of Clinical Pulmonary Medicine

基　　金：卫生部科研项目(编号:wkj2006-2-026);江苏省"333工程"资助项目(苏人才办2007-16-09)

摘　　要：目的以TGF-β1诱导A549细胞出现上皮细胞-间质细胞转化(epithelial-mesenchymal transition,EMT),探讨EMT过程及其信号转导途径在肺纤维化中的作用。方法体外培养A549细胞,以TGF-β1进行干预,收集不同时段的细胞,用荧光实时定量PCR检测上皮及间质细胞标志物的mRNA表达,Western blot检测上皮及间质细胞的标志物以及信号转导蛋白P-Smad2/3、Snail1、Snail2的表达,应用倒置相差显微镜观察TGF-β1干预前后细胞形态学的变化。结果 TGF-β1干预后,A549细胞上皮细胞标志物的mRNA和蛋白表达下调(P<0.05),间质细胞标志物的mRNA和蛋白表达上调(P<0.05);信号转导蛋白P-Smad2/3、Snail1上调(P<0.05),snail2弱表达(P>0.05);倒置相差显微镜观察到TGF-β1干预后A549细胞由鹅卵石状变为梭形,形态如同肌纤维母细胞。结论 TGF-β1可以在体外诱导肺泡上皮细胞向间质细胞转化,其机制与Smad 2/3、Snail1信号转导途径相关,提示肺泡上皮细胞向间质细胞的转化是肺纤维化发生的直接原因,而Smad 2/3、Snail1信号转导途径很可能是关键环节。通过诱导或促进肺泡上皮细胞向间质细胞转化,可以促使肺纤维化的发病,而通过阻断这一过程及其下游的信号转导通路有望治疗肺纤维化。Objective By inducing epithelial-mesenchymal transition（EMT） of A549 cells in vitro with transforming growth factorβ1（TGF-β1）,to investigate the role of EMT of alveolar epithelial cells and its signalling pathways in the mechanisms underlying pulmonary fibrosis.Methods A549 cells cultured in vitro were treated by TGF-β1,then harvested at different time points to assay the expression of the markers of epithelial cell and mesenchymal cell by Real-time PCR and Western blot,to assay the expression of signal transducer P-Smad2/3,Snail1 and Snail2 by Western blot.Cellular morphology changes were observed by phase-contrast microscope before and after A549 cells being treated by TGF-β1.Results After A549 cells being treated by TGF-β1,mRNA and protein expression of epithelial markers was down-regulated（P〈0.05）and that of mesenchymocyte markers up-regulated（P〈0.05）.Signal transducers P-Smad2/3,Snail1 were also up-regulated（P〈0.05）,with a weak expression of snail2（P〉0.05）.A549 cells were observed by inverted phase contrast microscope to turn from pebble shape to Fusiform shape,a myofibroblast-like morphology.Conclusions TGF-β1 could induce EMT of alveolar epithelial cells in vitro,associated with signal transduction pathway Smad2/3 and Snail1.All that suggested EMT of alveolar epithelial cells might be fundamental mechanism of pulmonary fibrosis and pathway Smad2/3 and Snail1 might be the key points.Pulmonary fibrosis could be urged to onset by induceing or promoting EMT of alveolar epithelial cells,and be expected to be cured by blocking the process of EMT and its signalling pathways.

关 键 词：转化生长因子Β1 A549细胞 上皮细胞间质转化 肺纤维化 

分 类 号：R563.9[医药卫生—呼吸系统]