Effect of Regulating FUNDC1 Mitophagy-Mediated cGAS/STING Pathway in Oleic Acid-Induced Acute Lung Injury Model.

Acute lung injury (ALI) involves inflammatory cytokines and chemokines, resulting in lung and multiple organ injuries. This study explored the mechanism of mitophagy and cGAS/STING pathway in oleic acid (OA)-induced ALI. Mice and pulmonary microvascular endothelial cells were divided into four groups: control group (Con), ALI group, FUNDC1 ^-/- control group (F-Con), and FUNDC1 ^-/- ALI group (F-ALI). After 24 h of modeling, proceed with tissue collection. Lung tissues were stained using hematoxylin eosin. Autophagosomes were observed by electron microscope and mtDNA was detected by qPCR. Western blot was used to analyze protein expression of pathways cGAS, STING, pTBK1, pIRF3, and pNF-κB. Serum IFN-β expression was detected by ELISA. Cellular morphological changes were observed using microscopy. LDH level, cGAS, and STING in endothelial cells were observed. Compared with control group, pathological changes in ALI group were significantly aggravated. Expressions of serum IFN-β, cGAS, STING, pTBK1, pIRF3, and pNF-κB in lung tissues of ALI mice were significantly higher than control group. After OA, the morphology of lung microvascular endothelial cells changed and LDH expression increased. After FUNDC1 gene was knocked out to inhibit mitophagy, autophagosomes were significantly reduced and mtDNA increased. Expressions of pathway proteins in lung tissues and cells of FUNDC1 ^-/- ALI group were higher than those of wild-type ALI group. Serum IFN-β expression also increased. Silencing FUNDC1 inhibits mitophagy. Subsequently, accumulated mtDNA activates cGAS/STING pathway, aggravating ALI pathological damage and inflammation, suggesting that mitophagy may provide protection in OA-induced ALI through cGAS/STING pathway.