Molecular Mechanisms of Vascular Calcification

血管钙化的预防部分由基质玻璃蛋白（MGP）和肝脏ABC介导 转运蛋白C6（AbccG）。MGP是一种分泌性基质蛋白，可能通过以下方式影响体内血管钙化： 通过γ-羧基化谷氨酸结合骨形态发生蛋白（BMP）和/或钙。我们 数据显示，在血管细胞中，BMP-2/4诱导激活素样激酶受体1（ALK 1）的表达， TGF-3受体在血管发育中的作用ALK 1也在动脉粥样硬化病变中表达， 促进培养的病变细胞的聚集和增殖。ALK 1受体的诱导使BMP- 2/4调节血管内皮生长因子和MGP的表达，这提供了一个反馈回路 以限制BMP活性。该途径在动脉粥样硬化形成中的重要性尚不清楚。Abcc 6是一种膜 主要在肝脏中表达的转运蛋白。在我们以前的研究中， 整合基因组学方法，并显示出防止血管钙化。Abcc 6缺陷 与以进行性钙化为特征的弹性纤维性假黄瘤有关， 加速动脉粥样硬化Abcc 6的作用位点和机制尚不清楚。这 本申请集中于MGP和Abcc 6预防血管钙化的机制，以及MGP和Abcc 6的抗血管钙化作用。 ALK 1和Abcc 6在动脉粥样硬化形成中作用。将讨论四个具体目标。具体目标1： 确定BMP结合相对于钙结合对于MGP抑制血管生成的能力的重要性， 在小鼠体内使用同源重组进行钙化。在具体目标2中，我们将确定 BMP-2/4诱导ALK 1 - 1表达所需的受体和信号通路。 受体使用siRNA，显性负性受体和分子抑制剂体外。第3章将 阐明Abcc 6及其相关通路，并确定其抑制作用的位点和分子基础。 使用体外和体内技术对血管钙化的影响。在第四个目标中，我们将 解决了调节ALK 1和Abcc 6的表达对建立的肿瘤细胞中病变发展的影响， 小鼠动脉粥样硬化模型。

Prevention of vascular calcification is mediated in part by Matrix Gla Protein (MGP) and the hepatic ABC transporter C6 (AbccG). MGP is a secreted matrix protein and may affect vascular calcification in vivo by binding bone morphogenetic proteins (BMP) and/or calcium through gamma-carboxylated glutamates. Our data show that in vascular cells BMP-2/4 induce expression of the activin-like kinase receptor 1 (ALK1), an essential TGF-3 receptor in vascular development. ALK1 is also expressed in atherosclerotic lesions and promotes aggregation and proliferation of cultured lesion cells. Induction of the ALK1 receptor allows BMP- 2/4 to regulate expression of vascular endothelial growth factor and MGP, which provides a feed back loop to limit BMP-activity. The importance of this pathway in atherogenesis is unknown. Abcc6 is a membrane transporter that is mainly expressed in the liver. AbccG was identified in our previous studies using an integrative genomics approach, and was shown to protect against vascular calcification. Abcc6 deficiency has been associated with pseudoxanthoma elasticum that is characterized by progressive calcification and accelerated atherosclerosis. The site and the mechanism of action of Abcc6 are not understood. This application focuses on the mechanisms by which MGP and Abcc6 prevent vascular calcification, and the effect of ALK1 and Abcc6 on atherogenesis. Four specific aims will be addressed. In Specific Aim 1; we will determine the importance of BMP-binding versus calcium-binding for the ability of MGP to inhibit vascular calcification in vivo using homologous recombination in mice. In Specific Aim 2, we will identify the receptor(s) and signaling pathway(s) that are required for BMP-2/4 to induce expression of the ALK1- receptor using siRNA, dominant negative receptors and molecular inhibitors in vitro. Specific Aim 3 will address Abcc6 and Abcc6 related pathways and determine the site and the molecular basis of its inhibitory effect on vascular calcification using both in vitro and in vivo techniques. Finally, in Specific Aim 4, we will address the effects of modulating expression of ALK1 and Abcc6 on lesion development in established mouse models of atherosclerosis.