Single-cell RNA-seq reveals cellular heterogeneity of mouse carotid artery under disturbed flow
Fengchan Li, Kunmin Yan, Lili Wu, Zhong Zheng, Yun Du, Ziting Liu, Luyao Zhao, Wei Li, Yulan Sheng, Lijie Ren, Chaojun Tang, Li Zhu
Abstract
Abstract Disturbed blood flow (d-flow) has been known to induce changes of the cells in the arterial wall, increasing the risk of atherosclerosis. However, the heterogeneity of the vascular cell populations under d-flow remains less understood. To generate d-flow in vivo, partial carotid artery ligation (PCL) was performed. Seven days after ligation, single-cell RNA sequencing of nine left carotid arteries (LCA) from the PCL group (10,262 cells) or control group (14,580 cells) was applied and a single-cell atlas of gene expression was constructed. The integrated analysis identified 15 distinct carotid cell clusters, including 10 d-flow-relevant subpopulations. Among endothelial cells, at least four subpopulations were identified, including Klk8 hi ECs, Lrp1 hi ECs, Dkk2 hi ECs, and Cd36 hi ECs. Analysis of GSVA and single-cell trajectories indicated that the previously undescribed Dkk2 hi ECs subpopulation was mechanosensitive and potentially transformed from Klk8 hi ECs under d-flow. D-flow-induced Spp1 hi VSMCs subpopulation that appeared to be endowed with osteoblast differentiation, suggesting a role in arterial stiffness. Among the infiltrating cell subpopulations, Trem2 hi Mφ, Birc5 hi Mφ, DCs, CD4 + T cells, CXCR6 + T cells, NK cells, and granulocytes were identified under d-flow. Of note, the novel Birc5 hi Mφ was identified as a potential contributor to the accumulation of macrophages in atherosclerosis. Finally, Dkk2 hi ECs, and Cd36 hi ECs were also found in the proatherosclerotic area of the aorta where the d-flow occurs. In conclusion, we presented a comprehensive single-cell atlas of all cells in the carotid artery under d-flow, identified previously unrecognized cell subpopulations and their gene expression signatures, and suggested their specialized functions.