Background: Acute respiratory distress syndrome (ARDS) is multiple inflammatory injury lung disease. MiR-27a-3p alleviates lung injury, whether miR-27a-3p could affect the lung inflammation is not clear. Therefore, we established the lipopolysaccharides (LPS)-induced alveolar epithelial cell model to simulate ARDS inflammation in vitro to investigate the effect of miR-27a-3p in ARDS. Methods: After LPS-induced alveolar epithelial cell model was established and FOXO3 was proved to be targeted by miR-27a-3p, the miR-27a-3p mimic, inhibitor, or FOXO3-overexpression plasmids were transfected into the cells. The effects of miR-27a-3p and FOXO3 on cell viability and apoptosis were then evaluated. The levels of apoptosis-/inflammation-related factors, miR-27a-3p, and FOXO3 were further analyzed. Also, the activities of reactive oxygen species (ROS) and nicotinamide adenine dinucleotide phosphate (NAPDH) in cells were examined. Results: MiR-27a-3p was down-regulated in LPS-induced alveolar epithelial cells. The decreased-cell viability of the LPS-induced cells was increased by miR-27a-3p mimic while inhibited by FOXO3. The enhanced-apoptosis, and up-regulated Bax and C caspase-3 were reduced by miR-27a-3p mimic while inhibited by FOXO3; the down-regulated Bcl-2 of the LPS-induced cells was increased by miR-27a-3p mimic while inhibited by FOXO3. The up-regulated IL-6, IL-8, ROS, and NAPDH in the LPS-induced cells were reduced by miR-27a-3p mimic while inhibited by FOXO3. Besides, FOXO3 reversed the effect of miR-27a-3p mimic on the LPS-induced cells. Conclusion: MiR-27a-3p targeted FOXO3 to mitigated inflammation and apoptosis of LPS-induced alveolar epithelial cells via suppressing NAPDH/ROS activation. (C) 2020 Elsevier Inc. All rights reserved.