LPS-treated alveolar epithelial cell line A549 induces down-regulation of miR-21 expression and its targeting regulation of PDCD4 to reduce apoptosis

Abstract

Objective To investigate the effect of microRNA (miR) -21 in lipopolysaccharide (LPS) -induced apoptosis of alveolar epithelial cell line A549. Methods A549 cells were treated with LPS, and the change in expression of miR-21 was determined by qRT-PCR. miR-21 mimics were transfected into A549 cells. The cell proliferation was measured by MTT, and the cell apoptosis was examined by flow cytometry. Western blotting was used to determine the expression level of C-capase-3 protein.The target gene prediction software predicted that programmed cell death protein 4 (PDCD4) might be the target gene of miR-21. Then, miR-21 mimics and pcDNA3.1-PDCD4 were co-transfected into A549 cells. The cell proliferation, apoptosis and change in C-capase-3 protein expression were measured by the above methods. Results The expression level of miR-21 decreased in LPS-treated A549 cells. The proliferation activity of A549 cells decreasedafter LPS treatment, and the apoptosis rate and C-capase-3 protein level increased. miR-21 mimics increased the proliferation activity of A549 cells, and decreased the apoptosis rate and C-capase-3 protein level under LPS conditions. miR-21 targeted negative regulation of PDCD4 expression. Up-regulation of PDCD4 inhibited the anti-LPS-induced apoptosis and proliferation of A549 cells by miR-21 mimics. Conclusion LPS induces down-regulation of miR-21 expression in A549 cells, and miR-21 targeting regulation of PDCD4 inhibits LPS-induced apoptosis in A549 cells. Key words: Alveolar epithelial cells; miR-21; Apoptosis; PDCD4; LPS