Vascular Calcification: Pericytes and Statins

描述(由申请人提供)： 我们假设病理性血管钙化是由局部 激活周细胞以表达其成骨细胞的“程序”并产生 动脉粥样硬化病变中的钙化基质。钙化 斑块是血栓栓塞症的重要危险因素， 心肌梗塞和中风--主要的医疗保健问题。周细胞是 驻留在动脉中的间充质细胞，并与 微血管内的内皮细胞。周细胞具有多能性 分化潜能，形成成骨细胞，血管平滑肌细胞， 依赖旁分泌调节的脂肪细胞、软骨细胞和成纤维细胞 来自相邻细胞的信号，细胞因子，生长因子，其他可溶性因子， 和细胞外基质。我们将使用原代大鼠和人类周细胞 探讨体外钙化的调控机制。因为没有 周细胞系，我们还将使人类周细胞永生 人端粒酶逆转录酶(hTERT-周细胞)在人卵巢癌组织中的表达 努力开发可靠的、与临床相关的研究模型。目标1 描述了控制可溶性因子和培养条件的作用 周细胞分化为钙化成骨样表型， 并试图通过基因芯片方法更清楚地定义这种表型。目标 2定义了配体依赖的信号通路，这些信号通路对 周细胞分化和钙化。在这里我们将测试我们的第二个 周细胞是降胆固醇他汀类药物靶点的假说 药物，通过调节富含胆固醇的预组装膜信号 复合体(小窝和脂筏)和/或附件的预烯基化减少 信号蛋白。降胆固醇的他汀类药物对糖尿病有很强的疗效 治疗动脉粥样硬化，以及对骨量的重要作用。目标3 研究周细胞与某些细胞之间的细胞间相互作用。 动脉粥样硬化病变的主要邻居(内皮细胞， 巨噬细胞和泡沫细胞)可能启动和维持周细胞成骨 差异化。试管工作应该会产生一系列详细的信息 调控周细胞介导的因子和基因表达变化 钙化。在目标4中，这些标记随后将在体内进行研究 高胆固醇血症WHHL兔的钙化动脉粥样硬化病变 正在接受他汀类药物治疗，并在人类病理标本中。我们 相信这个项目将为新的治疗方法提供基础 治疗心血管钙化和动脉粥样硬化的策略。 本项目对RFA-HL-01-014做出回应，将3个领域的调查人员联系起来 血管钙化知识发展的关键：血管 细胞生物学(周细胞)、骨细胞生物学(成骨细胞分化、 膜信号，矿化基质，RANKL对巨噬细胞谱系的作用)， 动脉粥样硬化和他汀类药物的研究(兔和人的研究)。我们相信 这项提案用强大的技术解决了血管钙化问题， 独到的见解和新颖的调查途径。

DESCRIPTION (provided by applicant): We hypothesize that pathological vascular calcification is caused by the local activation of pericytes to express their osteoblast "program" and produce calcified matrix in the context of the atherosclerotic lesion. Calcified plaque is an important risk factor for thromboembolism, myocardial infarction, and stroke - major healthcare issues. Pericytes are mesenchymal cells that reside in arteries and form gap junctions with endothelial cells in the microvasculature. Pericytes have multipotent differentiation potential, forming osteoblasts, vascular smooth muscle cells, adipocytes, chondrocytes, and fibroblasts depending on paracrine regulatory signals from adjacent cells, cytokines, growth factors, other soluble factors, and extracellular matrix. We will use primary rat and human pericytes to investigate the regulation of calcification in vitro. Because there are no pericyte cell lines, we will also immortalize human pericytes with forced expression of human telomerase reverse transcriptase (hTERT-pericyte) in an effort to develop a reliable, clinically relevant research model. Aim 1 characterizes the role of soluble factors and culture conditions that control differentiation of pericytes into the calcifying osteoblast-like phenotype, and attempts to more clearly define this phenotype by gene array methods. Aim 2 defines the ligand-dependent signaling pathways that are critical for pericyte differentiation and calcification. Here we will test our second hypothesis that pericytes are the target for cholesterol-lowering statin drugs, through modulation of cholesterol-rich preassembled membrane signaling complexes (caveolae and lipid rafts) and/or reduced prenylation of accessory signaling proteins. Cholesterol-lowering statin drugs have strong efficacy in treating atherosclerosis, as well as important actions on bone mass. Aim 3 studies the cell-cell interactions between pericytes and some of their principal neighbors in atherosclerotic lesions (endothelial cells, macrophages, and foam cells) that may initiate and sustain pericyte osteogenic differentiation. The in vitro work should yield a body of detailed information on factors and gene expression changes that regulate pericyte-mediated calcification. In Aim 4 these markers will then be investigated in vivo in calcifying atherosclerotic lesions of hypercholesterolemic WHHL rabbits undergoing statin drug therapy, and in human pathological specimens. We believe that this Project will provide a foundation for new therapeutic strategies to treat cardiovascular calcification and atherosclerosis. This Project responds to RFA-HL-01-014 by linking investigators in 3 areas critical to the advancement of knowledge of vascular calcification: vascular cell biology (pericytes), bone cell biology (osteoblast differentiation, membrane signaling, mineralized matrix, RANKL actions on macrophage lineage), and atherosclerosis and statin research (rabbit and human studies). We believe this proposal addresses vascular calcification with powerful technology, original insights, and novel avenues of investigation.