Extracellular vesicle-derived miR-1249-5p regulates influenza A virus-induced acute lung injury in RAW246.7 cells through targeting SLC4A1.

Acute lung injury (ALI) is characterized by tissue damage that leads to pulmonary epithelial membrane dysfunction and macrophage activation. Currently however, the exact mechanism by which the initial mediators of mouse lung epithelial (MLE-12) cells induce inflammation remines unclear. We constructed co-culture systems of MLE-12 cells with mouse macrophage cells RAW246.7 which were realized by the supernatant and Transwell chamber. In previous study, we successfully constructed an influenza A virus-induced MLE-12 cells model. Extracellular Vesicles (EVs) from cells supernatant were isolated by differential ultracentrifugation and confirmed by transmission electron microscopy. High-throughput sequencing results showed that MLE-12 cells stimulated by influenza A virus had higher level of miR-1249-5p. The results were validated by RT-qPCR analysis. The research aimed to investigate the roles and mechanisms of miR-1249-5p in ALI. RAW246.7 cells were transfected with miR-1249-5p mimic/inhibitor. The concentrations of TNF-α, IL-6 were determined by ELISA and the uptake of EVs was monitored by confocal laser scanning microscope. Western blotting detected changes in the SLC4A1 and NF-κB signaling pathway. The results indicated that miR-1249-5p played an important role in ALI, and further investigation of its target gene SLC4A1 and NF-κB signaling pathway provides ideas for new therapeutic targets and strategies for ALI.