Down-regulation of long non-coding RNA XIST aggravates sepsis-induced lung injury by regulating miR-16-5p

This study aims to explain the role and related mechanisms of long non-coding RNA (lncRNA) X inactive specific transcript (XIST) in sepsis-induced acute lung injury (ALI). The in vivo septic models and in vitro septic model were established. In animal models, the lung injury of the rats was evaluated after XIST was overexpressed. In cell models, the effects of XIST and microRNA (miR)-16-5p on ALI was detected by MTT assay, Western blot and ELISA. The interaction between XIST and miR-16-5p was investigated by bioinformatics analysis, dual-luciferase reporter assay, RIP assay and RNA pull-down assay. We found that XIST expression was down-regulated in lung tissues of septic rats and lipopolysaccharide-stimulated cells, while the expression of miR-16-5p was up-regulated. Down-regulation of XIST significantly promoted pulmonary edema, increased the levels of TNF-α, IL-1β and malondialdehyde, inhibited the cell viability and decreased the level of superoxide dismutase. Mechanistically, it was confirmed that XIST could sponge miR-16-5p, and thus repress its expression, and the transfection of miR-16-5p mimics could reverse the effects of XIST over-expression in the cell model. Collectively, it is concluded that XIST reduces sepsis-induced ALI via regulating miR-16-5p.