Abstract:

Objective To detect the expression of miRNA in the serum of children with severe pneumo⁃nia，and to explore the effects and mechanisms of miR⁃137 and miR⁃342⁃3p on the proliferation and apoptosis oflung epithelial cells. Methods qRT⁃PCR was used to detect the expression of miRNA and REG3A mRNA inserum samples of children with severe pneumonia and healthy children；Lung epithelial cells A549 were randomlydivided into blank control group，miR⁃137 NC group，miR⁃137 mimic group，miR⁃342⁃3p NC group，miR⁃342⁃3pmimic group，qRT ⁃ PCR detects miR ⁃ 137，miR ⁃ 342 ⁃ 3p and REG3A mRNA expression，Western Blot detectsREG3A，Caspase⁃3，Bcl⁃2，Bax and p53 protein expression，the double luciferase reporter gene experimentdetects fluorescence activity，CCK⁃8 method and EdU staining detected cell proliferation，flow cytometry detectedcell apoptosis. Results The relative expression levels of miR⁃425⁃5p，miR⁃137，miR⁃325⁃3p，miR⁃342⁃3p，miR⁃203a⁃3p and miR⁃9⁃3p in the serum of children with severe pneumonia were higher than those of healthy childrenand the relative expression of REG3A mRNA was lower（P < 0.05）；Both miR⁃137 and miR⁃342⁃3p and REG3A3′⁃UTR have base complementation，and their expression is regulated by targeting（P < 0.05）；Both miR⁃137 over⁃expression and miR⁃342⁃3p overexpression can reduce the proliferation activity of A549 cells，reduce the rate of EdUpositive cells，increase the rate of apoptosis and the expression of Caspase⁃3，Bax and p53 proteins，while Bcl⁃2Protein expression decreased（P < 0.05）. Conclusion miR⁃137 and miR⁃342⁃3p may inhibit lung epithelial cellproliferation and promote cell apoptosis by targeting REG3A.

Key words:

miRNA, lung epithelial cells, islet regeneration source protein 3A, proliferation, apoptosis