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 激活周细胞表达其成骨细胞“程序”并产生 钙化基质在动脉粥样硬化病变的背景下。钙化 斑块是血栓栓塞的重要危险因素， 心肌梗塞和中风-主要的健康问题。周细胞是 间充质细胞存在于动脉中，并与 微血管系统中的内皮细胞。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， 脂肪细胞、软骨细胞和成纤维细胞依赖于旁分泌调节 来自相邻细胞的信号、细胞因子、生长因子、其它可溶性因子， 和细胞外基质。我们将使用原代大鼠和人类周细胞， 探讨体外钙化的规律。因为没有 周细胞系，我们也将永生人类周细胞与强制 人端粒酶逆转录酶（hTERT-pericyte）在人结肠癌细胞中的表达 努力开发一个可靠的，临床相关的研究模型。要求1 表征了可溶性因子和培养条件的作用， 周细胞分化成钙化成骨细胞样表型， 并试图通过基因阵列方法更清楚地定义这种表型。目的 2定义了配体依赖性信号传导途径，这些途径对于 周细胞分化和钙化。在这里，我们将测试我们的第二个 假设周细胞是降胆固醇他汀类药物的靶点 药物，通过调节富含胆固醇的预组装膜信号 复合物（小窝和脂筏）和/或减少的辅助 信号蛋白降胆固醇他汀类药物在 治疗动脉粥样硬化，以及对骨量的重要作用。目标3 研究周细胞和它们的一些细胞之间的细胞间相互作用， 动脉粥样硬化病变中的主要邻居（内皮细胞， 巨噬细胞和泡沫细胞），可以启动和维持周细胞成骨 分化体外实验应该会产生大量详细的信息 对调节周细胞介导的 钙化在目标4中，然后将在体内研究这些标记物， 高胆固醇血症WHHL兔钙化性动脉粥样硬化病变 进行他汀类药物治疗，以及在人类病理标本中。我们 我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。 本项目通过连接3个领域的研究者来响应RFA-HL-01-014 对血管钙化知识的进步至关重要：血管 细胞生物学（周细胞），骨细胞生物学（成骨细胞分化， 膜信号传导、矿化基质、RANKL对巨噬细胞谱系的作用）， 以及动脉粥样硬化和他汀类药物研究（兔子和人类研究）。我们认为 该提议利用强大的技术解决血管钙化， 原创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.