Single-Cell Transcriptome Analysis Reveals Dynamic Populations of Vascular Cells in Neointimal Hyperplasia

Background: Neointimal hyperplasia (NIH) is the pathological basis of vascular injury disease. Vascular cells are the dominant cells in the process of NIH, but the extent of heterogeneity amongst them is still unclear. Methods: A mouse model of NIH was constructed by inducing carotid artery ligation. Single-cell sequencing was then used to analyze the transcriptional profile of vascular cells. Cluster features were determined by functional enrichment analysis, gene set scoring, pseudo-time analysis, and cell-cell communication analysis. Additionally, immunofluorescence staining was conducted on vascular tissues from fibroblast lineage-traced (PdgfraDreER-tdTomato) mice to validate the presence of Pecam1+Pdgfra+tdTomato+ cells. Results: The left carotid arteries (ligation) were compared to right carotid arteries (sham) from ligation-induced NIH C57BL/6 mice. Integrative analyses revealed a high level of heterogeneity amongst vascular cells, including fourteen clusters and seven cell types. We focused on three dominant cell types: endothelial cells (ECs), vascular smooth muscle cells (vSMCs), and fibroblasts. The major findings were: (1) four subpopulations of ECs, including ECs4, mesenchymal-like ECs (ECs1 and ECs2), and fibro-like ECs (ECs3); (2) four subpopulations of fibroblasts, including pro-inflammatory Fibs-1, Sca1+ Fibs-2, collagen-producing Fibs-3, and mesenchymal-like Fibs-4; (3) four subpopulations of vSMCs, including vSMCs-1, vSMCs-2, vSMCs-3, and vSMCs-3-derived vSMCs; (4) ECs3 express genes related to extracellular matrix (ECM) remodeling and cell migration, and fibro-like vSMCs showed strong chemokine secretion and relatively high levels of proteases; (5) fibro-like vSMCs that secrete Vegfa interact with ECs mainly through vascular endothelial growth factor receptor 2 (Vegfr2). Conclusions: This study presents the dynamic cellular landscape within NIH arteries and reveals potential relationships between several clusters, with a specific focus on ECs3 and fibro-like vSMCs. These two subpopulations may represent potential target cells for the treatment of NIH.