A Bioinformatics Analysis Of Underlying Molecular Mechanisms Of Concanavalin A-induced Murine Hepatitis

Objective:To explore the mechanisms of fulminant hepatitis (FH) at very early stage, and to find out critical pathways that play a key role in its initiation and progression. Also, we conduct this study to understand microRNA (miRNA)'s regulation role in this process.Methods:Twelve Bald/C mice were divided into four groups:one group left as negative control and sacrificed immediately after injection of PBS (Phosphate Buffered Saline), another three groups with concanavalin A administration sacrificed at 1 h,3 h, and 6 h correspondingly after injection. Affymetrix GeneChip(?) Mouse 430 2.0 Array was employed to evaluate the expression profile of each of the 12 samples. Significant analysis was done on the microarray data to extract the genes that were differentially expressed. Also enrichment analysis was carried out to find out relevant pathways within which regulated genes were significantly enriched. The expression profiling of miRNA from liver tissues was also analyzed by microarray. The differentially expressed miRNAs, were subjected to time-series profile analysis, their predicted target genes were also subject to enrichment analysis of annotation terms, and their overlapping with up/down regulated genes were also tested.Results:We found 393,8354 and 11344 differentially expressed genes at 3 time points correspondingly. During 0-1 h and 1-3 h, most of the pathways enriched with regulated genes were related to immune response and inflammation, Among which, Toll-like receptor (TLR) signaling and MAPK signaling appeared during both phases, while Cytokine (CK)-CK receptor interaction, Apoptosis, T cell receptor signaling, and Natural killer (NK) cell mediated cytotoxicity pathways emerged during the second phase. Pathways that found significant during 3-6 h were mostly related to metabolic process. Eleven microRNAs among multi-Class were found to be significantly differentially expressed, and their target genes were enriched in the following annotation terms:as Leukocyte transendothelial migration, Antigen processing and presentation, Cell cycle and cell death. Also the regulated genes found during expression analysis were found to be significantly enriched in candidate targets of differential expressed miRNAs. Three miRNAs:mmu-miR-465a-5p, mmu-miR-377 and mmu-miR-155, they ranked high in differential expression and degree of enrichment of regulated genes in their corresponding targets.Conclusion:The TLR signaling pathway dominates the early responses of ConA induced FH on mouse. It stimulate the production of typeâ… cytokines, therefore recruiting and activating T/NK cells. Activated T/NK cells exert their cytotoxicity on hepatocytes through inducing apoptosis intermediated by death receptors, resulting in liver injury. The whole process is evidently regulated by miRNA to a greater or less degree.