Genome-wide map of N6-methyladenosine circular RNAs identified in mice model of severe acute pancreatitis

BACKGROUND

Severe acute pancreatitis (SAP) is a deadly inflammatory disease with complex pathogenesis and lack of effective therapeutic options. N⁶-methyladenosine (m⁶A) modification of circRNAs plays important roles in physiological and pathological processes. However, the roles of m⁶A circRNA in the pathological process of SAP remains unknown.

AIM

To identify transcriptome-wide map of m⁶A circRNAs and to determine their biological significance and potential mechanisms in SAP.

METHODS

The SAP in C57BL/6 mice was induced using 4% sodium taurocholate salt. The transcriptome-wide map of m⁶A circRNAs was identified by m⁶A-modified RNA immunoprecipitation sequencing. The biological significance of circRNAs with differentially expressed m⁶A peaks was evaluated through gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis. The underlying mechanism of m⁶A circRNAs in SAP was analyzed by constructing of m⁶A circRNA-microRNA networks. The expression of demethylases was determined by quantitative polymerase chain reaction and western blot to deduce the possible mechanism of reversible m⁶A process in SAP.

RESULTS

Fifty-seven circRNAs with differentially expressed m⁶A peaks were identified by m⁶A-modified RNA immunoprecipitation sequencing, of which 32 were upregulated and 25 downregulated. Functional analysis of these m⁶A circRNAs in SAP found some important pathways involved in the pathogenesis of SAP, such as regulation of autophagy and protein digestion. In m⁶A circRNA–miRNA networks, several important miRNAs participated in the occurrence and progression of SAP were found to bind to these m⁶A circRNAs, such as miR-24-3p, miR-26a, miR-92b, miR-216b, miR-324-5p and miR-762. Notably, the total m⁶A level of circRNAs was reduced, while the demethylase alkylation repair homolog 5 was upregulated in SAP.

CONCLUSION

m⁶A modification of circRNAs may be involved in the pathogenesis of SAP. Our findings may provide novel insights to explore the possible pathogenetic mechanism of SAP and seek new potential therapeutic targets for SAP.