Role of miR-455-3p in the alleviation of LPS-induced acute lung injury by allicin.

Acute lung injury (ALI) is a type of diffuse lung injury that seriously affects the survival of critically ill patients. MicroRNAs (miRNAs) can serve as promising therapeutic targets or offer insights for the development of potential therapeutic strategies against ALI. In our previous study, we demonstrated the protective effect of allicin in ALI, but the role of miRNAs in the alleviation of ALI by allicin remains unclear. This study aimed to investigate whether miRNAs mediate the effects of allicin on ALI. Cell viability and proliferation were determined using CCK-8 and EdU assays, respectively, while cellular apoptosis was analyzed by flow cytometry. The claudin-4 protein was detected by quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) and western blotting. The binding of miR-455 with claudin-4 was determined by bioinformatics analysis and validated by dual luciferase reporter assays. The lung wet/dry ratio of lipopolysaccharide (LPS)-treated rats was determined by hematoxylin and eosin (HE) and TUNEL staining of the pulmonary tissues. The levels of myeloperoxidase (MPO), interleukin (IL)-2, IL-6, and tumor necrosis factor (TNF)-α were determined by enzyme-linked immunosorbent assay (ELISA). We observed that allicin alleviated LPS-induced injury in A549 cells, and claudin-4 knockdown reversed the protective effect of allicin in ALI. Claudin-4 is a direct target of miR-455-3p, and miR-455-3p overexpression partially reversed the protective effect of allicin in LPS-treated A549 cells. Subsequent in vivo experiments confirmed that allicin protects against LPS-induced ALI by regulating the miR-455-3p/claudin-4 axis. The study revealed that the protective effect of allicin in ALI is mediated via miR-455-3p, which suppresses the expression of claudin-4.