Region-specific gene expression and sex inform about disease susceptibility in the aorta

Pathology in large vessels frequently develops at specific locations, implying that local stressors and spatially restricted gene expression are likely contributors to disease susceptibility. Here we perform single-cell transcriptomics in the carotids, the aortic arch and the thoracic and abdominal aorta to identify site- and sex-specific differences that could inform about vulnerability. Our findings revealed (1) regionally defined transcriptional profiles, (2) signatures associated with embryonic origins and (3) differential contributions of sex-specific effectors. Furthermore, cross-referencing regional-specific signatures with available genome-wide association study and expression quantitative trait loci databases identified 339 disease candidates associated with aorta distensibility, stiffness index and blood pressure. CPNE8 and SORBS2 were further evaluated and highlighted as strong causal candidates. Sex differences were predominantly observed in the thoracic and abdominal aorta. MCAM (CD146), a transcript with sex-skewed expression and lower in male mice and men, had significantly reduced expression in human aortic aneurysms. The findings reveal underlying diversity within vascular smooth muscle cell populations relevant to understanding site-specific and sex-specific variation of vascular pathologies.