Single cell mapping of large and small arteries during hypertensive aging

Vascular aging is directly related to several major diseases including hypertension and atherosclerosis, in which endothelial dysfunction and smooth muscle phenotype changes are crucial. However, cell types within the vessel wall and their dynamic cellular communication status have not been characterized in different arteries during hypertensive aging. To depict the interconnectedness of complex mechanism between hypertension and aging, we performed single cell RNA sequencing of aorta, femoral and mesentery artery, respectively from Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) aging 16-72 weeks. We found that aging and hypertension alone have a significant impact on the alteration of cellular composition and artery remodeling both on conductive and resistant arteries, even greater when superimposed. Consistently, smooth muscle cells (SMCs) underwent phenotypic switching from contractile towards synthetic, apoptotic and senescent SMCs with aging/hypertension. We identified three sub-clusters of Spp1high synthetic SMCs, Spp1high matrix activated fibroblasts and Spp1high scar-associated macrophage involved in hypertensive aging, highlighting that Spp1, encoding protein osteopontin (OPN), could be a potential regulator participating in hypertensive aging. Spp1high scar-associated macrophage enriched for ROS metabolic process, supramolecular fiber organization and actin filament organization. Cell-cell communication analysis also revealed SPP1-Cd44 receptor pairing was markedly aggravated on hypertensive aging condition. Importantly, the concentration of OPN in human serum significantly potentiated in hypertension patient compared with normal group. Thus, we provide a comprehensive cell atlas to systematically resolve the cellular diversity and dynamic cellular communication changes of the vessel wall during hypertensive aging, highlight the mechanisms of vascular vasodilation through cGMP-PKG signaling pathway and identified a protein marker osteopontin as a potential regulator of vascular remodeling during hypertensive aging.血管衰老与高血压、动脉粥样硬化等多种重大疾病直接相关，其中内皮功能障碍和平滑肌表型改变为核心致病环节。然而，目前尚未明确高血压衰老过程中不同动脉血管壁内的细胞类型及其动态细胞通讯状态。为阐明高血压与衰老之间的复杂相互作用机制，我们对16至72周龄的Wistar京都大鼠（WKY）及自发性高血压大鼠（SHR）的主动脉、股动脉和肠系膜动脉开展了单细胞RNA测序。研究发现，单纯衰老或单纯高血压即可显著改变传导性动脉与阻力性动脉的细胞组成并引发血管重构，当二者共同作用时影响更为显著。与之相符的是，伴随衰老与高血压进程，平滑肌细胞（SMCs）发生了表型转换：从收缩型转变为合成型、凋亡型及衰老型SMC。我们鉴定出高血压衰老过程中参与致病的三个细胞亚群：Spp1high合成型平滑肌细胞、Spp1high基质活化成纤维细胞及Spp1high瘢痕相关巨噬细胞；研究表明，编码骨桥蛋白（osteopontin, OPN）的Spp1基因或可作为高血压衰老的潜在调控因子。Spp1high瘢痕相关巨噬细胞显著富集活性氧（ROS）代谢、超分子纤维组装及肌动蛋白丝组织等生物学过程。细胞间通讯分析同样显示，在高血压衰老状态下，SPP1-Cd44受体配对的信号交流显著增强。值得注意的是，与健康对照组相比，高血压患者血清中的骨桥蛋白（OPN）浓度显著升高。综上，本研究构建了一套完整的细胞图谱，可系统解析高血压衰老过程中血管壁的细胞多样性及动态细胞通讯变化，阐明了通过cGMP-PKG信号通路实现血管舒张的潜在机制，并鉴定出骨桥蛋白可作为高血压衰老过程中血管重构的潜在蛋白标志物。