Remodeling of the circRNA Landscape in Myocardial Infarction Integrates Nuclear Regulation, DNA Damage Response, and Cardiomyocyte Structural Pathways

Plasma circular RNAs (circRNAs) are stable RNA molecules found in blood, which makes them potential noninvasive biomarkers for acute myocardial infarction (MI). The aim of this study was to describe the plasma circRNA profile in patients with acute MI and to identify circRNA markers that may help detect heart injury and reflect the biological processes involved. We compared plasma samples from patients with acute MI and healthy controls using total RNA sequencing with unique molecular identifiers (UMIs). After sequencing, reads were processed through quality control, alignment, duplicate removal, and circRNA detection. Differential expression was analyzed after adjusting for age, sex, smoking, and technical factors. Several circRNAs were significantly different between MI cases and controls and were able to separate the two groups in principal component and receiver operating characteristic analyses. Among the most increased circRNAs were hsa-PASK_0004, hsa-STXBP3_0002, hsa-RCAN3_0002, and hsa-RANBP9_0044, while hsa-HIF1A_0002, hsa-SUZ12_0049, hsa-PNRC1_0001, and hsa-RAB2A_0002 were decreased. Several candidates showed AUC values above 0.7. Pathway analysis linked the host genes of these circRNAs to inflammation, platelet activation, coagulation, and cardiomyocyte stress responses. Overall, these findings suggest that circulating circRNAs may serve as useful blood-based markers of MI and provide insight into the molecular changes that accompany acute MI.