MiR-24 Attenuates Oxidative Stress and Mitochondrial Apoptosis in Ventilator-Induced Lung Injury by Targeting Bcl-2-related Ovarian Killer.

Mechanical ventilation (MV), though life-saving in acute respiratory distress syndrome (ARDS), can cause ventilator-induced lung injury (VILI). MicroRNA-24 (miR-24) has been implicated in regulating inflammation and apoptosis, but its role in VILI remains unexplored. Therefore, our study aimed to explore the role of mechanism of miR-24 in VILI. MiR-24 expression was analyzed in MV-induced ARDS rat models (GSE57223), plasma from ARDS patients, and cyclic stretch (CS)-treated alveolar epithelial cells. Functional studies included intratracheal delivery of miR-24-agomir in rats with VILI and transfection of miR-24 mimic in CS-exposed cells. Inflammatory cytokines, oxidative stress markers, apoptosis, and mitochondrial dysfunction were assessed using ELISA, RT-qPCR, TUNEL, JC-1 staining, and ATP assays. BOK was identified as a target of miR-24 via bioinformatics, luciferase reporter, and RNA pull-down assays. Rescue experiments using BOK overexpression vectors (pcDNA3.1/BOK) were conducted in both models to confirm functional interaction. MiR-24 was significantly downregulated in ARDS patients and VILI models and positively correlated with oxygenation index. Overexpression of miR-24 attenuated MV- and CS-induced inflammation, oxidative damage, and mitochondrial apoptosis dysfunction. BOK was confirmed as a direct target of miR-24; its expression was upregulated in ARDS and VILI and inversely correlated with miR-24 levels. Silencing of BOK attenuated MV-induced inflammation, oxidative damage, and apoptosis in rats. Importantly, BOK overexpression reversed the protective effects of miR-24 both in vivo and in vitro, confirming its role as a key downstream effector. Receiver operating characteristic (ROC) analysis showed that miR-24 had good diagnostic potential (AUC = 0.834). Overall, MiR-24 protects against MV-induced lung injury by targeting BOK and modulating key injury pathways. The miR-24/BOK axis offers a promising therapeutic avenue for ARDS-associated VILI.