Abstract：
The ascending aorta is a common location for aneurysm and dissection. This aortic region is populated by a mosaic of medial and adventitial cells that are embryonically derived from either the second heart field (SHF) or the cardiac neural crest. SHF-derived cells populate areas that coincide with the spatial specificity of thoracic aortopathies. The purpose of this study was to determine whether and how SHF-derived cells contribute to ascending aortopathies.
Ascending aortic pathologies were examined in patients with sporadic thoracic aortopathies and angiotensin II (AngII)-infused mice. Ascending aortas without overt pathology from AngII-infused mice were subjected to mass spectrometry-assisted proteomics and molecular features of SHF-derived cells were determined by single-cell transcriptomic analyses. Genetic deletion of either Lrp1 (low-density lipoprotein receptor-related protein 1) or Tgfbr2 (transforming growth factor-β receptor type 2) in SHF-derived cells was conducted to examine the effect of SHF-derived cells on vascular integrity.
Pathologies in human ascending aortic aneurysmal tissues were predominant in outer medial layers and adventitia. This gradient was mimicked in mouse aortas after AngII infusion that was coincident with the distribution of SHF-derived cells. Proteomics indicated that brief AngII infusion before overt pathology occurred evoked downregulation of smooth muscle cell proteins and differential expression of extracellular matrix proteins, including several LRP1 ligands. LRP1 deletion in SHF-derived cells augmented AngII-induced ascending aortic aneurysm and rupture. Single-cell transcriptomic analysis revealed that brief AngII infusion decreased Lrp1 and Tgfbr2 mRNA abundance in SHF-derived cells and induced a unique fibroblast population with low abundance of Tgfbr2 mRNA. SHF-specific Tgfbr2 deletion led to embryonic lethality at E12.5 with dilatation of the outflow tract and retroperitoneal hemorrhage. Integration of proteomic and single-cell transcriptomics results identified PAI1 (plasminogen activator inhibitor 1) as the most increased protein in SHF-derived smooth muscle cells and fibroblasts during AngII infusion. Immunostaining revealed a transmural gradient of PAI1 in both ascending aortas of AngII-infused mice and human ascending aneurysmal aortas that mimicked the gradient of medial and adventitial pathologies.
SHF-derived cells exert a critical role in maintaining vascular integrity through LRP1 and transforming growth factor-β signaling associated with increases of aortic PAI1.
Ascending aortic pathologies were examined in patients with sporadic thoracic aortopathies and angiotensin II (AngII)-infused mice. Ascending aortas without overt pathology from AngII-infused mice were subjected to mass spectrometry-assisted proteomics and molecular features of SHF-derived cells were determined by single-cell transcriptomic analyses. Genetic deletion of either Lrp1 (low-density lipoprotein receptor-related protein 1) or Tgfbr2 (transforming growth factor-β receptor type 2) in SHF-derived cells was conducted to examine the effect of SHF-derived cells on vascular integrity.
Pathologies in human ascending aortic aneurysmal tissues were predominant in outer medial layers and adventitia. This gradient was mimicked in mouse aortas after AngII infusion that was coincident with the distribution of SHF-derived cells. Proteomics indicated that brief AngII infusion before overt pathology occurred evoked downregulation of smooth muscle cell proteins and differential expression of extracellular matrix proteins, including several LRP1 ligands. LRP1 deletion in SHF-derived cells augmented AngII-induced ascending aortic aneurysm and rupture. Single-cell transcriptomic analysis revealed that brief AngII infusion decreased Lrp1 and Tgfbr2 mRNA abundance in SHF-derived cells and induced a unique fibroblast population with low abundance of Tgfbr2 mRNA. SHF-specific Tgfbr2 deletion led to embryonic lethality at E12.5 with dilatation of the outflow tract and retroperitoneal hemorrhage. Integration of proteomic and single-cell transcriptomics results identified PAI1 (plasminogen activator inhibitor 1) as the most increased protein in SHF-derived smooth muscle cells and fibroblasts during AngII infusion. Immunostaining revealed a transmural gradient of PAI1 in both ascending aortas of AngII-infused mice and human ascending aneurysmal aortas that mimicked the gradient of medial and adventitial pathologies.
SHF-derived cells exert a critical role in maintaining vascular integrity through LRP1 and transforming growth factor-β signaling associated with increases of aortic PAI1.
摘要：
升主动脉是动脉瘤和夹层的常见位置。该主动脉区域由来自第二心脏区域（SHF）或心脏神经c的胚胎衍生的内侧和外膜细胞的马赛克填充。SHF衍生的细胞填充与胸主动脉病变的空间特异性一致的区域。这项研究的目的是确定SHF衍生的细胞是否以及如何促进升主动脉病变。
在散发性胸主动脉病变和血管紧张素II（AngII）输注小鼠的患者中检查了升主动脉病变。对来自AngII输注小鼠的无明显病理的升主动脉进行质谱辅助蛋白质组学，并通过单细胞转录组学分析确定SHF衍生细胞的分子特征。进行SHF衍生细胞中Lrp1（低密度脂蛋白受体相关蛋白1）或Tgfbr2（转化生长因子-β受体2型）的遗传缺失，以检查SHF衍生细胞对血管完整性的影响。
人升主动脉瘤组织中的病理以外中间层和外膜为主。在AngII输注后在小鼠主动脉中模拟该梯度,这与SHF衍生细胞的分布一致。蛋白质组学表明，在明显病理之前短暂输注AngII会引起平滑肌细胞蛋白的下调和细胞外基质蛋白的差异表达，包括几个LRP1配体。SHF衍生细胞中的LRP1缺失增加了AngII诱导的升主动脉瘤和破裂。单细胞转录组分析显示，短暂的AngII输注降低了SHF衍生细胞中Lrp1和Tgfbr2mRNA的丰度，并诱导了具有低丰度Tgfbr2mRNA的独特成纤维细胞群体。SHF特异性Tgfbr2缺失导致E12.5处的胚胎致死率，并伴有流出道扩张和腹膜后出血。蛋白质组学和单细胞转录组学的整合结果鉴定了PAI1（纤溶酶原激活物抑制剂1）是AngII输注期间SHF衍生的平滑肌细胞和成纤维细胞中增加最多的蛋白质。免疫染色显示，注入AngII的小鼠的升主动脉和人类升动脉瘤主动脉中PAI1的透壁梯度模仿了内侧和外膜病理的梯度。
SHF来源的细胞通过LRP1和与主动脉PAI1增加相关的转化生长因子-β信号传导在维持血管完整性中发挥关键作用。
在散发性胸主动脉病变和血管紧张素II（AngII）输注小鼠的患者中检查了升主动脉病变。对来自AngII输注小鼠的无明显病理的升主动脉进行质谱辅助蛋白质组学，并通过单细胞转录组学分析确定SHF衍生细胞的分子特征。进行SHF衍生细胞中Lrp1（低密度脂蛋白受体相关蛋白1）或Tgfbr2（转化生长因子-β受体2型）的遗传缺失，以检查SHF衍生细胞对血管完整性的影响。
人升主动脉瘤组织中的病理以外中间层和外膜为主。在AngII输注后在小鼠主动脉中模拟该梯度,这与SHF衍生细胞的分布一致。蛋白质组学表明，在明显病理之前短暂输注AngII会引起平滑肌细胞蛋白的下调和细胞外基质蛋白的差异表达，包括几个LRP1配体。SHF衍生细胞中的LRP1缺失增加了AngII诱导的升主动脉瘤和破裂。单细胞转录组分析显示，短暂的AngII输注降低了SHF衍生细胞中Lrp1和Tgfbr2mRNA的丰度，并诱导了具有低丰度Tgfbr2mRNA的独特成纤维细胞群体。SHF特异性Tgfbr2缺失导致E12.5处的胚胎致死率，并伴有流出道扩张和腹膜后出血。蛋白质组学和单细胞转录组学的整合结果鉴定了PAI1（纤溶酶原激活物抑制剂1）是AngII输注期间SHF衍生的平滑肌细胞和成纤维细胞中增加最多的蛋白质。免疫染色显示，注入AngII的小鼠的升主动脉和人类升动脉瘤主动脉中PAI1的透壁梯度模仿了内侧和外膜病理的梯度。
SHF来源的细胞通过LRP1和与主动脉PAI1增加相关的转化生长因子-β信号传导在维持血管完整性中发挥关键作用。
