Long non-coding RNA OIP5-AS1 aggravates acute lung injury through promoting inflammation and cell apoptosis via regulating miR-26a-5p/TLR4 axis

Abstract

\n Background: Acute lung injury (ALI) is a pulmonary disorder that leads to acute failure of respiration and thereby results in a high mortality worldwide. Increasing studies have verified that TLR4 is a promoter in ALI, however, the underlying upstream mechanisms of TLR4 was still rarely investigated. Methods: Lipopolysaccharide (LPS) was used to induce cell model and animal model. A wide range of experiments including RT-qPCR, Western blot, ELISA, flow cytometry, H&E staining, RIP, luciferase activity and caspase-3 activity were carried out to figure out the expression status, specific role and potential upstream mechanism of TLR4.Result: RT-qPCR identified that TLR4 expression was upregulated in ALI mice and LPS-induced WI-38 cells. Moreover, miR-26a-5p was confirmed to target TLR4 according to luciferase reporter assay. Besides, miR-26a-5p overexpression decreased the contents of proinflammatory factors (TNF-α and IL-1β) and restrained cell apoptosis, while upregulation of TLR4 reversed these effects of miR-26a-5p mimics, implying that miR-26a-5p alleviated ALI through regulating TLR4. Afterwards, OIP5-AS1 was identified to bind with miR-26a-5p by RNA immunoprecipitation (RIP) and luciferase reporter assay. Functionally, OIP5-AS1 upregulation accelerated the inflammation injuries and miR-26a-5p overexpression counteracted the influence of OIP5-AS1 upregulation on proinflammatory factors and cell apoptosis.Conclusion: OIP5-AS1 accelerated ALI through regulating miR-26a-5p/TLR4 axis in ALI mice and LPS-induced cells, which indicates a promising insight into diagnostics and therapeutics in ALI.