Detailed profiling of m6A modified circRNAs and synergistic effects of circRNA and environmental risk factors for coronary artery disease

The modification of N6-methyladenosine (m6A) modification is implicated in human diseases. However, considerable uncertainty is associated with the regulatory mechanisms of m6A circRNAs in coronary artery disease (CAD), which require further clarification. In this study, m6A-modified RNA immunoprecipitation sequencing (MeRIP-seq) was conducted to investigate m6A-modified circRNAs in human coronary artery smooth muscle cells (HCASMCs) and to identify potential biomarkers for CAD. A total of 830 and 331 up- and down-regulated m6A peaks, (corresponding to 463 and 243 up- and down-regulated circRNAs, respectively), were identified in HCASMCs in a pathological condition. Functional analysis suggested that these circRNAs appeared to participate in intracellular protein, histone deacetylase complex, ATP-dependent activity, autophagy, and AMPK signaling pathway. Four candidate circRNAs were selected for further evaluation in HCASMCs and human samples. The results suggested that hsa_circHECTD1 and hsa_circZBTB46 were significantly increased in patients with CAD (p-value = 0.039 and p-value = 0.014) and may act as potential diagnostic biomarkers of CAD. Furthermore, statistical results showed that hsa_circHECTD1 and hsa_circSEC62 were positively correlated with triglyceride (TG) (r = 0.213, p-value = 0.014) and Gensini Score (used to quantify the severity of CAD) (r = 0.349, p-value <0.001), respectively. Logistic regression revealed that hsa_circZBTB46 was strongly correlated with the incidence of CAD, and the synergistic effects of circRNAs and hypertension enhanced the risk of CAD. These results show that hsa_circHECTD1 and hsa_circZBTB46 may be new targets for further studies, and this study enhances our understanding of the effects of m6A-circRNAs on the pathogenesis of CAD.