LncRNA GAS5 suppresses inflammatory responses and apoptosis of alveolar epithelial cells by targeting miR-429/DUSP1.

Acute lung injury (ALI) is a life-threatening syndrome characterized by excessive inflammation and apoptosis of alveolar epithelial cells. This study firstly investigated the role and mechanism of long non-coding RNA (lncRNA) growth arrest-specific 5 (GAS5) in regulating lipopolysaccharide (LPS)-induced inflammatory response and apoptosis of murine alveolar epithelial cell line MLE-12. The expression of GAS5, miR-429, and dual-specificity phosphatase 1 (DUSP1) were examined using quantitative Real-Time PCR (qRT-PCR) and western blot. The inflammatory responses were evaluated by detecting the levels of pro-inflammatory cytokines using ELISA. Cell apoptosis was assessed by TUNEL assay. The interactions among GAS5, miR-429, and DUSP1 were examined using luciferase reporter assay. The results showed that GAS5 and DUSP1 expression were decreased, whereas miR-429 was increased in lung tissues from LPS-induced ALI mice and LPS-treated MLE-12 cells. Furthermore, GAS5 overexpression decreased cell inflammatory responses and apoptosis in LPS-treated MLE-12 cells, which was reversed by miR-429 mimic and DUSP1 knockdown. Mechanistically, GAS5 acted as a competitive endogenous RNA by sponging miR-429 to facilitate DUSP1 expression. Our findings suggest that GAS5 suppresses inflammatory responses and apoptosis of alveolar epithelial cell MLE-12 by targeting miR-429/DUSP1 axis.