MicroRNA-674-5p/5-LO axis involved in autoimmune reaction of Concanavalin A-induced acute mouse liver injury

Autoimmune hepatitis is characterized, in part, by the pathways involving cysteinyl-leukotriene metabolites of arachidonic acid, the dynamics of which remain unclear. Here, we explored post-transcriptional regulation in the 5-lipoxygenase (5-LO) pathway of arachidonic acid in a Concanavalin A (Con A) induced mouse model. We found that Con A administration lead to 5-LO overexpression and cysteinyl-leukotriene release in early hepatic injury, which was attenuated by cyclosporin A pretreatment. Subsequent microarray and qRT-PCR analysis further showed that microRNA-674-5p (miR-674-5p) displayed a significant decrease in expression in Con A-damaged liver. Noting that miR-674-5p harbors a potential binding region for 5-LO, we further transfected hepatic cell lines with overexpressing miR-674-5p mimic and discovered a negative regulating effect of miR-674-5p on 5-LO expression in the presence of IL-6 or TNF-α. These findings suggest that miR-674-5p might be a negative regulator in 5-LO mediated autoimmune liver injury, representing a compelling avenue towards future therapeutic interventions.