内质网应激在肺泡上皮间质转分化发生中的作用

Effect of endoplasmic reticulum stress during the alveolar epithelium mesenchymal transdifferentiation process

目的探讨衣霉素诱导的内质网应激在肺泡上皮细胞-间质转分化(EMT)中的影响及作用机制。方法以质量浓度为1.25、2.5、5.0 mg/L的衣霉素(TM)分别处理人肺腺癌上皮细胞A549 24 h,MTT法检测细胞活力;RTPCR和免疫印迹法检测GRP78、CHOP、E-钙粘蛋白(E-cadherin)、Smad2/3、转录因子Snail的表达;以5μg/L TGF-β1分别处理A549细胞24 h或48 h后,免疫印迹法检测GRP78和p-e IF2α的表达。结果 1.25 mg/L的TM处理A549细胞24 h后,GRP78 mRNA和蛋白表达升高,CHOP mRNA表达上调;E-cadherin蛋白表达下降,Smad2/3活化,Snail表达上调。而TGF-β1处理A549 24 h,GRP78和p-eIF2α表达均上调。结论衣霉素诱导的内质网应激可介导A549细胞发生EMT,同时EMT发生过程中伴随着内质网应激的发生。

Objective To explore the effect and action mechanism of endoplasmic reticulum stress induced by tunicamycin （TM） in alveolar epithelial-mesenchymal transdifferentiation （EMT）. Methods Lung adenocarcinoma epithelial ceils A549 were treated with TM with quality concentration of 1.25, 2.5, 5 mg/L for 24 h. Cell vitality was determined by MTT. The expression of GRP78, CHOP, E-cadherin, Smad2/3 and Snail was detected by RT-PCR and Western blotting. Then A549 was treated with 5 μg/L TGF-β1 for 24 h or 48 h, and the expression of GRP78 and p-eIF2α was detected by Western blotting. Results After A549 cells were exposed to 1.25 mg/L TM for 24 h, the GPR78 mRNA and protein expression was up-regulated; CHOP mRNA expression was up-regulated; E-cadherin protein expression was down-regulated; Smad2/3 was activated and Snail protein expression was up-regulated. However, after A549 was exposure to TGF-β1 for 24 h, GRP78 and p-eIF2α expression were all up-regulated. Conclusion Endoplasmic reticulum stress induced by tunicamycin can mediate EMT in A549 cells. Meanwhile, the occurrence of EMT is accompanied by endoplasmie reticulum stress.