In this study, we aim to investigate the role of miR-30a-5p in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) using LPS-induced A549 cells and mice. We found cell viability was significantly declined accompanied by cell apoptosis and cell cycle arrest at G0/G1 phase in LPS-treated A549 cells. MiR-30a-5p was down-regulated by LPS treatment and miR-30a-5p significantly protected A549 cells from LPS-induced injury by increasing cell viability, reducing cell apoptosis, promoting cell cycle progression, and inhibiting inflammatory reactions. Dual-luciferase activity demonstrated that RUNX2 was a direct target for miR-30a-5p and its expression was negatively and directly regulated by miR-30a-5p. Over-expression of RUNX2 weakened the inhibitory effect of miR-30a-5p on inflammatory injury. In vivo, over-expression of miR-30a-5p alleviated LPS-induced inflammatory responses and lung injury in LPS-administrated mice. Besides, miR-30a-5p repressed LPS-elevated phosphorylation levels of the signal transducer and activator of transcription 3 (STAT3) and c-Jun N-terminal kinase (JNK), IκBα degradation, and NF-κB p65 phosphorylation. In conclusion, miR-30a-5p ameliorates LPS-induced inflammatory injury in A549 cells and mice via targeting RUNX2 and related signaling pathways, thereby influencing the progression of ARDS.
Keywords: ALI; ARDS; LPS; RUNX2; miR-30a-5p.