The effect of miRNA-29b-3p on lipopolysaccharide (LPS)-induced apoptosis and inflammatory responses of the alveolar epithelial cells targeting the Bax gene

摘要

To investigate the activity of miRNA-29b-3p on lipopolysaccharide (LPS)-induced apoptosis and inflammatory responses of human pulmonary alveolar epithelial cells (HPAEpiC). The HPAEpiCs were divided into the control, LPS, LPS+miRNA-NC, and LPS+miRNA-29b-3p groups. Flow cytometric analysis was performed to test the occurrence of apoptosis. Enzyme-linked immunosorbent assay was used for testing the following inflammatory factors: IL-6, IL-10, and TNF-alpha levels. The real-time quantitative reverse transcription polymerase chain reaction technique was employed to determine the miRNA-29b-3p levels, and related Bax gene of Bcl-2 which were detected by the western blotting technique. Bioinformatics software predictions showed that there were complementary sequences of miRNA-29b-3p included in 3' UTR of the Bax gene, also the dual luciferase reporter gene assay confirmed the targeting association between miRNA-29b-3p and the Bax gene. In comparison with the control group, the level of apoptosis recorded in IL-6 and TNF-alpha inflammatory factors of the HPAEpiCs in the LPS group was seen to have increased (P < 0.05), and the level of IL-10 and miRNA-29b-3p reduced greatly (P < 0.05). In comparison with the LPS+miRNA-NC group, the rate of HPAEpiCs apoptosis in the LPS+miRNA-29b-3p group reduced greatly (P < 0.05); while the level of Bcl-2 protein increased (P < 0.05), IL-6, IL-10, TNF-alpha inflammatory factors, and Bax protein levels decreased apparently (P < 0.05). Negative regulation of the miRNA-29b-3p on Bax gene expression in the HPAEpiCs was recorded. There was an over-expression of the Bax gene reversed action of miRNA-29b-3p on the LPS-induced HPAEpiCs apoptosis and inflammatory factor expression. The over-expression of miRNA-29b-3p can inhibit LPS-induced apoptosis and inflammation of the HPAEpiCs, which may influence the down-regulation of the Bax gene.