[Analysis on the expression profile of circRNAs in hypertrophic myocardium mice]

Objective: To explore the differential expression of circRNAs and their potential impact on the pathophysiological process in cardiac hypertrophy. Methods: Six SPF C57BL/6J male mice, aged 8 to 10 weeks, were randomly divided into transverse aortic constriction (TAC) group (n=3) or sham operation(sham) group (n=3) according to random number table method. TAC mouse model was used to induce cardiac hypertrophy. Four weeks after surgery, high-throughput sequencing analysis was performed to detect differentially expressed circRNA in left myocardial tissues of mice between TAC group and sham group, and principal component analysis of circRNA was performed by R language software. Enrichment analysis was performed by GO and KEGG databases to predict the basic functions of differentially expressed circRNA-derived genes and their biological pathways. The differentially expressed circRNAs in the sequencing results were verified by real-time fluorescence quantitative polymerase chain reaction. Cytoscape software was used to construct circRNA-microRNA (miRNA) network maps to predict their interactions by combining differentially expressed circRNA and TargetScan predicted miRNA sites. Results: Principal component analysis was performed on 4 580 circRNAs detected from 6 samples of mice in TAC group and sham group. The results of R language software indicated that the variance contribution rate of the first 3 principal components, namely the first, second and third principal components, was 91.01%, 3.19% and 2.01%, respectively, and the cumulative variance contribution rate of the 3 components was 96.21%. Among the differentially expressed circRNAs, 6 (19%) were up-regulated and 25 (81%) were down-regulated in the TAC group. GO analysis showed that differentially expressed circRNA was closely related to the occurrence and development of cardiac hypertrophy, and KEGG pathway analysis suggested that downregulated circRNA expression was involved in the regulation of actin cytoskeleton. Fifteen out of the 31 differentially expressed circRNAs were selected for real-time fluorescence quantitative polymerase chain reaction verification, and the results showed that 8 circRNAs were consistent with sequencing results. circRNA-miRNA co-expression network analysis results showed that chr11:65218529-65233184-interacts with mmu-miRNA-30e-3p and mmu-miRNA-30a-3p. Conclusions The differential expression of circRNA in hypertrophic myocardium mice is evidenced in TAC mouse model. circRNA may interact with the corresponding miRNA to influence the occurrence and development of cardiac hypertrophy through autophagy-related cellular hypertrophy pathway or apoptosis-related pathological phenotypes.