The role of circRNAs in the regulation of myocardial angiogenesis in coronary heart disease

Circ-MBOAT2 Regulates Angiogenesis via the miR-495/NOTCH1 Axis and Associates with Myocardial Perfusion in Patients with Coronary Chronic Total Occlusion

Revascularization of coronary chronic total occlusion (CTO) still remains controversial. The factors that impact collateral circulation and myocardial perfusion are of interest. Circular RNA (circRNA) has been shown to regulate the process of angiogenesis. However, the effects of circ-membrane-bound O-acyltransferase domain containing 2 (circ-MBOAT2) on angiogenesis in patients with CTO were unclear. In this study, we evaluated circulating circRNAs and miRNAs in patients with CTO and stable coronary artery disease using high-throughput sequencing. Another cohort of patients were selected to verify the expressions of circ-MBOAT2 and miR-495. The role and mechanism of circ-MBOAT2 in the process of angiogenesis were explored through in vitro and vivo studies. Finally, we came back to a clinical perspective and investigated whether circ-MBOAT2 and miR-495 were associated with the improvement of myocardial perfusion evaluated by single-photon emission computed tomography (SPECT). We found that the expression of circ-MBOAT2 was significantly up-regulated while miR-495 was significantly down-regulated in patients with CTO. The expression of circ-MBOAT2 was negatively correlated with miR-495 in patients with CTO. In an in vitro study, we found that circ-MBOAT2 promoted tube formation and cell migration via the miR-495/NOTCH1 axis in endothelial cells. In an in vivo study, we showed that the inhibition of miR-495 caused the increase in collateral formation in mice after hindlimb ischemia. In a human study, we showed the expressions of circ-MBOAT2 and miR-495 were associated with myocardial perfusion improvement after revascularization of CTO. In conclusion, circ-MBOAT2 regulates angiogenesis via the miR-495/NOTCH1 axis and associates with myocardial perfusion in patients with CTO. Our findings suggest that circ-MBOAT2 and miR-495 may be potential therapeutic targets and prognostic factors for patients with CTO.

Comprehensive analysis of the RNA transcriptome expression profiles and construction of the ceRNA network in heart failure patients with sacubitril/valsartan therapeutic heterogeneity after acute myocardial infarction

Sacubitril/valsartan has a noteworthy advantage in improving ventricular remodelling, as well as reducing cardiovascular mortality and the rate of heart failure (HF) readmission. However, clinically, some patients with HF still have low sensitivity to sacubitril/valsartan, indicating sacubitril/valsartan resistance (SVR). A total of 46 patients with HF after AMI (23 SVR and 23 non-sacubitril/valsartan resistance (NSVR)) were selected. Five SVR and 5 matched NSVR samples were screened for differentially expressed ncRNAs along with mRNAs. A total of 124 differentially expressed miRNAs, 137 circRNAs, 237 lncRNAs and 50 mRNAs were screened by RNA sequencing technology. After quantitative real-time PCR (qRT‒PCR) verification of selected biomarkers in 18 pairs of samples, we found that for patients with SVR, hsa-miR-543, hsa-miR-642b-5p, hsa-miR-760, hsa_circ_0137499, ENST00000474394, ENST00000528337, E2F1, NEAT1, and YTHDF2 were upregulated, and hsa-miR-424-5p, hsa-miR-21-3p, hsa_circRNA_0003275, hsa_circRNA_0004494, hsa_circ_0093522, ENST00000467951, ENST00000558177, ACTA2, ANPEP, and CAMP were downregulated. Then, with the help of our constructed ceRNA network and functional annotation enrichment, we speculated that inflammatory pathways (such as the apelin signalling pathway) and lipid metabolism pathways (such as fatty acid metabolism) may be involved in the regulation of SVR. These discoveries lay a foundation for further mechanistic research and provide a direction for individualized drug administration.