miR-29c对二氧化硅诱导的肺成纤维细胞转分化抑制作用的研究

The inhibition effect of miR-29c on lung fibroblasts transdifferentiation induced by SiO2

目的探讨miR-29c对二氧化硅(SiO2)诱导的肺成纤维细胞向肌成纤维细胞转分化过程的调控作用。方法取清洁级成年健康雄性SD大鼠1只,分离培养大鼠的肺成纤维细胞,与肺巨噬细胞(NR8383)共培养构建SiO2诱导的肺纤维化体外细胞模型,使用实时定量聚合酶链反应(RT-qPCR)和免疫印迹(Westernblot)实验检测共培养细胞模型中成纤维细胞miR-29c和α-平滑肌肌动蛋白(α-SMA)表达量的改变。构建miR-29c过表达和抑制表达的矽肺体外细胞模型,观察α-SMA基因和蛋白表达水平的变化。结果与对照组比较,SiO2处理12、18h后肺巨噬细胞-肺成纤维细胞共培养体系中肺成纤维细胞miR-29c表达量明显下降,α-SMA表达量明显升高,差异均有统计学意义(P<0.05)。与空白对照组比较,转染miR-29c过表达或抑制表达病毒后,肺成纤维细胞α-SMA表达量出现相应的下降或升高,差异均有统计学意义(P<0.05)。结论miR-29c可能参与SiO2诱导的体外肺成纤维细胞转分化过程,通过抑制肺成纤维细胞向肌成纤维细胞的转分化从而阻碍SiO2诱导的肺纤维化。

Objective To investigate the regulatory effect of miR-29c on the trans-differentiation of pulmonary fibroblasts into myofibroblasts induced by silica dust. Methods Fibroblasts obtained from SD rat lung tissue and pulmonary macrophages (NR8383) were co-cultured to establish the silicosis cell model in vitro. And real time-quantitative polymerase chain reaction (RT-qPCR) and Western Blot assays were performed to detect the altered expression level of miR-29c and α-smooth muscle actin (α-SMA). After that, the in vitro cell model was transfected with corresponding viruses to establish miR-29c overexpression and inhibition cell models, and the mRNA and protein expression levels of α-SMA were detected simultaneously. Results Compared with control group, the expression level of miR-29c in the silicosis cell model in vitro was down-regulated significantly after 12 or 18 h exposed to SiO2, and both of the mRNA and protein expression levels of α-SMA were up-regulated instead (P<0.05). When transfected with corresponding viruses, the mRNA and protein expression levels of α-SMA in the pulmonary fibroblasts were significantly up-regulated in miR-29c inhibition group and down-regulated in miR-29c overexpression group (P<0.05). Conclusion Based on the findings, it could be safely infered that the development of pulmonary fibrosis could be impeded by inhibiting transdifferentiation process of pulmonary fibroblasts into myofibroblasts regulated by miR-29c, miR-29c could be an potential therapeutic target to lung fibrosis induced by silica.