Regulation of Vascular Calcification by Adventitial Endothelial Cells

项目总结/摘要 血管钙化影响约60%的60岁以上的成年人， 动脉粥样硬化动脉粥样硬化钙化是心血管发病率的独立危险因素， mortality.尽管进行了数十年的研究，但还没有令人信服的药物治疗可以预防或 逆转血管钙化。内膜（管腔）内皮形成血管系统的最内层。 在疾病条件下，内膜内皮细胞（EC）被刺激转化为骨祖细胞 细胞通过内皮-间充质转化并促进血管钙化。外膜中的EC 有助于血管疾病中的新血管生成。然而，很少有人知道外膜内皮细胞是否 与血管钙化有关。在骨发育过程中，由高表达的 EC标志物CD 31和糖蛋白内粘蛋白（Emcn）对于骨形成是关键的。我们的初步 使用基质玻璃蛋白（Mgp）敲除（Mgp-/-）小鼠作为血管钙化模型的研究揭示了两个 钙化动脉中不同的EC群，由CD 31 +Emcn-定义的内膜EC（i-EC）和 以CD 31 +Emcn+为特征的外膜EC（a-EC）。这两种EC亚型具有不同的Emcn表达， 在人类钙化动脉中也检测到了这种水平。批量RNA测序研究显示i-EC富集 在干细胞和成骨标志物中，a-EC表现出上调的Notch表达。内皮缺失 Notch 1基因减少了血管钙化，增加了Mgp-/-小鼠的存活率。在这一提议中， 我们假设a-EC支持动物模型血管钙化中的生物矿化， 人动脉粥样硬化病变，并密切调节Notch信号。在目标1中，我们将定义 使用单细胞RNA的血管钙化中a-EC（CD 31 +Emcn+）群体的分子特征 测序我们将描绘血管钙化中a-ECs的发育轨迹， 钙化的程度和严重程度。在目标2中，我们将确定内皮亚型（a-10）的贡献。 内皮细胞和i-EC）和Notch信号在动脉粥样硬化钙化中的作用。我们将研究内皮细胞- Notch 1受体在EC亚型、钙化和转录谱上的特异性缺失， 动脉粥样硬化病变拟议的研究将提供新的见解的基本机制， 内皮细胞生物学在动脉粥样硬化钙化中的作用， 治疗调制这些项目的完成将与得到指导的职业发展计划一起， 作为一个基础，以促进候选人过渡到一个成功的和独立的医生科学家 在心血管研究中。

PROJECT SUMMARY/ABSTRACT Vascular calcification affects ~60% of adults over 60 years of age and is frequently seen in patients with atherosclerosis. Atherosclerotic calcification is an independent risk factor for cardiovascular morbidity and mortality. Despite decades of research, no medical therapy has been convincingly established to prevent or reverse vascular calcification. The intimal (luminal) endothelium forms the innermost layer of the vasculature. Under disease conditions, the intimal endothelial cells (ECs) are stimulated to transform into osteoprogenitor cells through endothelial-mesenchymal transitions and contribute to vascular calcification. ECs in the adventitia contribute to neoangiogenesis in vascular disease. However, little is known about whether adventitial ECs are associated with vascular calcification. During bone development, a subset of ECs defined by high expression of the EC marker CD31 and the glycoprotein Endomucin (Emcn) are critical for bone formation. Our preliminary study using Matrix Gla Protein (Mgp) knockout (Mgp-/-) mice as a model of vascular calcification revealed two distinct populations of ECs in the calcified aortas, the intimal ECs (i-ECs) defined by CD31+Emcn- and the adventitial ECs (a-ECs) characterized by CD31+Emcn+. These two EC subtypes with distinct Emcn expression levels were also detected in human calcified arteries. Bulk RNA sequencing studies showed i-ECs were enriched in stem cell and osteogenic markers and a-ECs exhibited upregulated Notch expression. Endothelial deletion of the Notch1 gene reduced vascular calcification and increased the survival of the Mgp-/- mice. In this proposal, we hypothesize that a-ECs support the biomineralization in the vascular calcification in animal models and human atherosclerotic lesions, and are closely regulated by Notch signaling. In Aim 1, we will define the molecular signature of the a-EC (CD31+Emcn+) population in vascular calcification using single cell RNA sequencing. We will delineate the developmental trajectories of a-ECs in vascular calcification with correlation to the extent and severity of calcification. In Aim 2, we will determine the contribution of endothelial subtypes (a- ECs and i-ECs) and Notch signaling in atherosclerotic calcification. We will investigate the effect of endothelial- specific deletion of the Notch1 receptor on EC subtypes, calcification and transcriptional profiles in atherosclerotic lesions. The proposed studies will provide novel insight into the fundamental mechanisms of endothelial cell biology in atherosclerotic calcification and may identify potential gene targets for selective therapeutic modulation. Together with the mentored career development plan, the completion of the projects will serve as a foundation to facilitate the candidate to transition into a successful and independent physician scientist in cardiovascular research.