Regulatory Elements Harboring Common Coronary Artery Disease Risk Variants Control Endothelial TSPAN14 Expression and NOTCH1 Signaling

Background: Coronary artery disease (CAD) is a genetically complex condition and remains the leading cause of mortality worldwide. Genome-wide association studies (GWAS) have identified a CAD risk locus on chromosome 10q23 that is independent of traditional risk factors, providing an opportunity to uncover novel molecular mechanisms contributing to CAD pathogenesis. Methods: Improved fine-mapping approaches were used to prioritize noncoding variants at the 10q23 locus within the intronic region of Tetraspanin 14 (TSPAN14). Regulatory elements harboring lead variants were functionally interrogated using chromatin accessibility and CRISPR-mediated deletion approaches in endothelial cells (ECs). Subsequently, TSPAN14 function in ECs was assessed using transcriptomic profiling, Notch signaling activation assays, and EC functional assay using gene knockout (KO) cell lines. Results: Fine-mapping identified two lead variants, rs17680741 and rs12260962, located within regulatory elements predicted to affect TSPAN14 expression in monocytes and ECs, respectively. Chromatin accessibility and enhancer deletion assays demonstrated EC-specific function for rs12260962-harboring regulatory element in TSPAN14 expression regulation. Loss of TSPAN14 resulted in significant transcriptomic changes related to Notch signaling, heart morphogenesis, cell adhesion, and wound healing. Functionally, TSPAN14 KO ECs exhibited impaired cell-cell junction integrity, reduced repair capacity, and diminished mechanosensitive responses. Conclusions: Together, these data identify a regulatory element harboring CAD-associated variants at the 10q23 locus that modulates TSPAN14 expression and downstream Notch signaling in ECs, thereby linking genetic risk to endothelial dysfunction relevant to CAD pathogenesis.