MicroRNA-92a serves as a risk factor in sepsis-induced ARDS and regulates apoptosis and cell migration in lipopolysaccharide-induced HPMEC and A549 cell injury

Sepsis-induced acute respiratory distress syndrome (ARDS) is a common, high mortality complication in intensive care unit (ICU) patients. MicroRNA-92a (miR-92a) plays a role in many diseases, but its association with sepsis-induced ARDS is unclear. We enrolled 53 patients, including 17 with sepsis only, and 36 with sepsis-induced ARDS. Lipopolysaccharide (LPS) was used to stimulate pulmonary microvascular endothelial cells (HPMEC) and alveolar epithelial A549 cells, which were used to investigate the miR-92a roles in ARDS. MiR-92a expression levels in patient serum and cells were quantified using quantitative reverse transcription-polymerase chain reaction (RT-PCR), and protein expression was examined using Western blotting. The effect of miR-92a on apoptosis was examined using flow cytometry. Wound healing and transwell migration assays were used to evaluate cell migration. Serum miR-92a expression was higher in patients with sepsis-induced ARDS, when compared to patients with sepsis only. After LPS treatment in cells, miR-92a expression was higher when compared with control group, cell apoptosis and inflammatory responses were increased and cell migration was inhibited. However, cell apoptosis and inflammatory responses were decreased and cell migration was enhanced after miR-92a downregulation, when compared with inhibitor negative control (NC) group. Moreover, phosphorylated-Akt and phosphorylated-mTOR expression were increased after miR-92a inhibition. Our study provides evidence that circulating serum miR-92a could act as a risk factor for sepsis-induced ARDS. MiR-92a inhibition attenuated the adverse effects of LPS on ARDS through the Akt/mTOR signaling pathway.