百草枯诱导肺上皮细胞上皮间质转化促进肺纤维化

摘要

目的：观察百草枯（PQ）诱导人肺上皮 HPAEpiC 细胞发生上皮间质转化（EMT）作用及其调节机制。方法 MTT 法计算 PQ 对 HPAEpiC 细胞的半数抑制浓度（IC50）值，计算最适合诱导 HPAEpiC 细胞发生 EMT 的浓度，Tran-swell 检测证实 PQ 诱导肺上皮细胞体外迁移能力增强，酶联免疫吸附试验（ELISA）检测转化生长因子-β（TGF -β）变化。实时聚合酶链式反应（Real time - PCR）和免疫印迹法（Western blot）检测细胞 EMT 标志物及 TGF -β下游信号通路变化。结果 PQ 对 HPAEpiC 细胞的 IC50值为95.3μmol/ L，与 DMSO 对照组比较，PQ 可以诱导肺上皮 HPAEpiC 细胞形态发生 EMT 改变，并增加其体外迁移能力，PQ 可以促进肺上皮 HPAEpiC 细胞 TGF -β的分泌，并增加其下游Smad2/3、抑制 Smad7的蛋白表达；PQ 也可以增加间质性标志物 N - cadhenrin、波形蛋白（Vimentin）及基质金属蛋白酶2（MMP2）表达，抑制上皮性标志物 E - cadherin 表达。结论 PQ 在促进人肺上皮 HPAEpiC 细胞死亡的同时促进其向EMT 转化，提示 PQ 诱导肺纤维化的一种新机制。%Objective To investigate the mechanisms of paraquat(PQ)induced the epithelial - mesenchymal transition(EMT)in human lung epithelial HPAEpiC cells. Methods HPAEpiC cells IC50 were determined by MTT assay. The TGF - β was assayed by ELASA. The EMT and TGF - β related downstream mRNA and protein were also performed by real time PCR and Western blot in HPAEpiC cells following paraquat treatment. Results PQ IC50 cutoff in HPAEpiC cells is 95. 3 μmol/ L. Compared with DMSO control group,PQ could induce lung epithelial to mesenchymal transition morphogenesis change. PQ could also promote the secretion of TGF - β in pulmonary epithelial HPAEpiC cells,increase the downstream Smad2 / 3 and inhibit Smad7 expression. PQ could also increase the mesenchymal marker N - cadhenrin,Vimentin and MMP2 ex-pression,however inhibit the expression of E - cadherin. Conclusion PQ could promote human lung epithelial HPAEpiC cell death and further-more induce "EMT". Our conclusions provided a new mechanism for PQ - induced pulmonary fibrosis.