Single-cell and spatial transcriptomics map senescent vascular cells in arterial remodeling during atherosclerosis in mice.

Growing evidence suggests that the induction of cellular senescence in vascular cells is causally linked to the etiology of cardiovascular diseases. To investigate systematically the heterogeneity of senescent vascular cells in atherosclerosis, we used a high-fat diet and PCSK9 overexpression to induce atherosclerosis in a senescence reporter mouse model (p16-tdTomato^+/-) and performed single-cell RNA sequencing on whole aortas. Using the SenMayo and CellAge gene sets, we identified four clusters of vascular smooth muscle cells (VSMCs), fibroblasts and T cells enriched in features of senescence, which were reduced upon treatment with the senolytic agent ABT-737. We then derived a global senescence signature of atherosclerosis including Spp1, Ctsb and Tnfrsf11b mRNAs. We validated the enrichment of these mRNAs in senescence by using spatial transcriptomics in a second mouse model of atherosclerosis and senolysis (Ldlr^-/-; p16-3MR), as well as by analyzing in vitro models of human VSMC senescence. Our results uncover a vascular-specific transcriptomic signature of senescence that may be exploited for tracking and treating age-related vascular diseases.