Identification and verification of circRNA biomarkers for coronary artery disease based on WGCNA and the LASSO algorithm

Abstract Background: The role of circular RNAs (circRNAs) as biomarkers of coronary artery disease (CAD) remains poorly explored. The aim of the current study was to identify and validate potential circulating circRNA as biomarkers for the diagnosis of CAD. Methods:CircRNAs expression profile data of CAD was acquired from Gene Expression Omnibus (GEO) database. Differential gene expression analysis, weighted gene coexpression network analysis (WGCNA) and least absolute shrinkage and selection operation (LASSO) were used to screen CAD-related hub circRNAs. The expression levels of hub circRNAs were further verified by qRT-PCR in the blood of 100 CAD patients and 100 control individuals. The diagnostic potential of circRNAs was evaluated using logistic regression analysis, receiver operator characteristic (ROC) analysis, integrated discrimination improvement (IDI), and net reclassification improvement (NRI). Functional enrichment analysis were performed to predict the possible mechanisms of circRNAs in CAD. Results:Herein, 10 CAD-related hub circRNAs were revealed byWGCNA and Lasso analysis. Among these, hsa_circ_0069972 and hsa_circ_0021509 were highly expressed in blood samples of CAD patients, and they were identified as independent predictors after adjusting for relevant confounders. The area under the ROC curve of hsa_circ_0069972 and hsa_circ_0021509 were 0.760 and 0.717, respectively. The classification of patients was improved with the incorporation of circRNAs into the clinical model composed of conventional cardiovascular risk factors, showing an IDI of 0.131 and NRI of 0.170 for hsa_circ_0069972, and an IDI of 0.111 and NRI of 0.150 for hsa_circ_0021509. Functional enrichment analysis showed that hsa_circ_0069972-miRNA-mRNA network was enriched in TGF-β、FoxO and Hippo signaling pathways, and hsa_circ_0021509-miRNA-mRNA network was enriched in PI3K/Akt and MAPK signaling pathways. Conclusion: Hsa_circ_0069972 and hsa_circ_0021509 are identified by integrated analysis, and they are highly expressed in CAD patients. They may serve as novel biomarkers for CAD.