电离辐射下调miR-34a-5p促进辐射诱导的肺上皮间质转化

Down-regulation of miR-34a-5p by ionizing radiation promotes radiation-induced lung epithelial-mesenchymal transition

目的探究辐射下调miR-34a-5p在辐射诱导上皮间质转化(EMT)中的作用及其机制。方法Western blotting和流式细胞术检测60Coγ射线照射后肺上皮细胞中EMT相关标志蛋白的表达变化;RT-qPCR检测60Coγ射线照后不同时间点A549细胞和BEAS-2B细胞中miR-34a-5p的表达;将miR-34a-5p过表达或敲低后,Western blotting检测辐射诱导时EMT的表达。生物信息学预测miR-34a-5p的靶基因,RT-qPCR和Western blotting检测miR-34a-5p对靶基因的调控效果。结果6 Gy 60Coγ射线照射后48 h肺上皮细胞发生EMT,RT-qPCR检测显示miR-34a-5p表达下调;过表达miR-34a-5p可逆转辐射诱导的EMT,下调表达miR-34a-5p时,CD44表达升高,并且促进电离辐射诱导的EMT。结论60Coγ射线下调miR-34a-5p促进辐射诱导肺上皮细胞发生EMT,提示miR-34a-5p可能抑制辐射诱导EMT及放射性肺纤维化,有望成为放射性肺纤维化防治的新靶点。

Objective To explore the role and mechanism of radiation-induced miR-34a-5P in radiation-induced epithelial-mesenchymal transition(EMT).Methods We used Western blotting and flow cytometry to detect EMT-related marker protein expression in lung epithelial cells after 60Coγ-ray irradiation.The expression of miR-34a-5p in lung cancer cells A549 and normal lung cells BEAS-2B was initially screened by Real-time qPCR(RT-qPCR)at different time points after 60Coγ-ray irradiation.The effect of miR-34a-5p on radiation-induced EMT was detected by Western blotting.The miR-34a-5p target gene was predicted by bioinformatics,and the regulatory effect of miR-34a-5p on the target gene was detected by RT-qPCR and Western blotting.Results EMT occurred in lung epithelial cells 48 h after 6 Gy 60Coγ-ray irradiation.The expression of miR-34a-5p was down-regulated in 6 Gy 60Coγ-ray irradiated lung epithelial cells detected by RT-qPCR,and down-regulation of expressed miR-34a-5p might promote ionizing radiation-induced EMT by up-regulating CD44.Conclusion miR-34a-5p,down-regulated by 60Coγ-ray,negative regulation radiation,induced EMT in lung epithelial cells,suggesting that miR-34a-5p may play a role in inhibiting radiation-induced EMT and radiation induced pulmonary fibrosis(RIPF).It is expected to become a new target for the prevention and treatment of RIPF.