The Mechanism Underlying MicroRNA-31 In Acetaminophen Induced Drug-induced Liver Injury

Objective: Acetaminophen(APAP)is widely used as the antipyretic and analgesic drug in clinic.Its excessive abuse can result in severe drug-induced hepatotoxicity and irreversible liver failure.Inflammatory cells act as key roles in the drug-induced liver injury.Non-coding RNA(microRNA,miRNAs)are important regulators for inflammatory cytokines,among them microRNA-31 is closely associated with inflammatory regulation pathways.In this study,we investigated the role of microRNA-31 in drug-induced liver injury and its potential mechanism.Content and Method: By intraperitoneal injecting APAP in C57 BL/6 mouse,we investigated the fold change of microRNA-31 in this drug-induced liver injury model.Comparing with wide-type mouse,microRNA-31 knockout mouse show an incline of aggravation for liver injury.The results of hematoxylin-eosin staining and serum transaminase emphasize the different level of liver injury among WT and microRNA-31 knockout group.SYBR Green RT-PCR was used to detect the expression of inflammatory cytokines.Furthermore,Nano materials mixed with mimics were injected through the tail vein to build an over-expressive microRNA-31 model.The role of microRNA-31 was confirmed by this model.We used bioinformatics software to predict the potential targets of microRNA-31.Taqman real time quantitative PCR was used to detect the expression of target genes in various mouse model.Reporter gene assays and site-directed mutagenesis system to identify the target of miR-31 and overexpressing or knockout of miR-31 in mouse models determined the effect on mRNA and protein level of the potential target.Result: Our study showed that microRNA-31 knockout mouse enhanced the level of APAP-induced liver injury.The elevation of serum ALT and AST,aug mentation of hematoxylin-eosin staining area and high expressive level of inflammatory cytokines CXCL10、CCL5、IL6、TNFa confirmed the protective effect of microRNA-31 in liver injury.On contrast,the serum ALT and AST,HE area and expression of inflammatory cytokines decreased when miR-31 was overexpressed.Finally,we found E-selectin was the target gene of miR-31.The mRNA and protein levels of E-selectin were overexpressed in miR-31 knockout mouse,while these indexes were decreased in miR-31 over expressive models.Conclusion: MiR-31 plays an important role in drug-induced liver injury.MiR-31 can protect the liver injury by suppress the expression of inflammatory cytokines.E-selectin is the target gene of miR-31,which can be regulated by miR-31 in the process of liver injury.