Circular RNA expression profile of liver tissues in an EtOH-induced mouse model of alcoholic hepatitis

Alcoholic hepatitis (AH) is a widely prevalent liver-related disease that results from long-term alcohol consumption. However, there is still a lack of effective treatment. Previous studies have reported that circular RNAs (circRNAs) are related to the development of various diseases. However, the function of circRNAs and their roles in AH are largely unknown. Therefore, we used bioinformatics analysis to investigate changes in circRNA expression and predict their functions in AH. An AH model was established in C57BL/6J mouse treated by Gao-binge modeling method, and then the circRNA profile of liver tissues was screened by Next Generation Sequencing. By comparing circRNA expression in liver tissues in AH model groups and normal controls, we identified that circRNAs were differently expressed during AH pathogenesis, and then differential expression levels of selected circRNAs were validated by qRT-PCR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were employed to predict the functions of these circRNAs. A total of 20 circRNAs were found to be differentially expressed in AH model groups (p ≤ 0.05) compared with the expression of the normal controls respectively. Among them, 9 circRNAs were significantly up-regulated, and the other 11 were down-regulated. Ten circRNAs were randomly selected to verify the reliability of these profiles by qRT-PCR. After obtaining the parental genes of the differentially expressed circRNAs, the top 30 enrichment GO entries and KEGG pathways were annotated. Then, we selected significantly differentially expressed circRNA (mm9_ circ_018725) for further analysis in vitro. Although the exact mechanisms and biological functions of these circRNAs in the development of AH need further exploration, our findings do suggest that knockdown of mm9_ circ_018725 could inhibit hepatocyte apoptosis induced by EtOH in vitro. In addition, suppression of mm9_ circ_018725 reduced the release of pro-inflammatory cytokines from EtOH-stimulated Raw264.7 cells. Thus, our study brings us closer to understanding the pathogenic mechanisms and finding new molecular targets for the clinical treatment of alcoholic hepatitis.