ADAMTS7 promotes smooth muscle foam cell expansion in atherosclerosis

Human genetic studies have repeatedly associated ADAMTS7 with atherosclerotic cardiovascular disease. Subsequent investigations in mice demonstrated that ADAMTS7 is proatherogenic and induced in response to vascular injury. However, the cell-specific mechanisms governing ADAMTS7 proatherogenicity remain unclear. To determine which vascular cell types express ADAMTS7, we interrogated single-cell RNA-seq of human carotid atherosclerosis and found ADAMTS7 expression in smooth muscle cells (SMCs), endothelial cells (ECs), and fibroblasts. We subsequently created SMC- and EC-specific Adamts7 conditional KO and transgenic mice. Conditional KO of Adamts7 in either cell type did not reduce atherosclerosis, whereas transgenic induction in either cell type increased atherosclerosis. In SMC transgenic mice, this increase coincides with an expansion of lipid-laden SMC foam cells and a decrease in fibrous cap formation. RNA-seq of Adamts7-overexpressing SMCs revealed an upregulation of lipid genes typically assigned to macrophages. Mechanistically, ADAMTS7 increases SMC oxidized LDL uptake through CD36, whose expression is upregulated by PU.1. Assay for transposase-accessible chromatin using sequencing (ATAC-seq) and motif analysis revealed increased chromatin accessibility at AP-1-enriched regions, consistent with AP-1-dependent remodeling of PU.1-regulated lipid-handling loci. In summary, ADAMTS7 promotes atherosclerosis by driving SMC foam cell formation through an AP-1/PU.1/CD36 regulatory axis.