Profiling and bioinformatics analyses of circular RNAs in myocardial ischemia/reperfusion injury model in mice

Myocardial ischemia/reperfusion (I/R) injury, which is associated with high morbidity and mortality, is a main cause of unexpected myocardial injury after acute myocardial infarction. However, the underlying mechanism remains unclear. Circular RNAs (circRNAs), which are formed from protein-coding genes, can sequester microRNAs or proteins, modulate transcription and interfere with splicing. Authoritative studies suggest that circRNAs may play an important role in myocardial I/R injury.

To explore the role and mechanism of circRNAs in myocardial I/R injury.

We constructed a myocardial I/R injury model using ligation of the left anterior descending coronary artery, and evaluated the success of the validated model using triphenyltetrazolium chloride and hematoxylin-eosin staining. Then, left ventricular samples from different groups were selected for mRNA-sequence, and differential gene screening was performed on the obtained results. The differentially obtained mRNAs were divided into up-regulated and down-regulated according to their expression levels, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis were performed, respectively. Then, the obtained circRNA and microRNA (miRNA) were paired for analysis, and the binding sites of miRNA and mRNA were virtual screened. Finally, the obtained circRNA, miRNA and mRNA were constructed by ceRNA mutual most useful network.

We used an RNA sequencing array to investigate the expression signatures of circRNAs in myocardial I/R injury using three samples from the I/R group and three samples from the sham group. A total of 142 upregulated and 121 downregulated circRNAs were found to be differentially expressed (fold change ≥ 2, P < 0.05). GO and KEGG functional analyses of these circRNAs were performed. GO analysis revealed that these circRNAs were involved mainly in cellular and intracellular processes. KEGG analysis demonstrated that 6 of the top 20 pathways were correlated with cell apoptosis. Furthermore, a circRNA-miRNA coexpression network and ceRNA network based on these genes were constructed, revealing that mmu-circ-0001452, mmu-circ-0001637, and mmu-circ-0000870 might be key regulators of myocardial I/R injury.

This research provides new insights into the mechanism of myocardial I/R, which mmu-circ-0001452, mmu-circ-0001637, and mmu-circ-0000870 are expected to be new therapeutic targets for myocardial I/R injury.