Stem Cells in Vascular Remodeling

描述(申请人提供)：心血管疾病占美国死亡人数的40%。动脉粥样硬化和再狭窄等血管疾病涉及广泛的血管重塑，如新生内膜的细胞增殖和迁移。血管平滑肌细胞(SMC)是血管壁中膜的主要细胞类型，一般为 公认成熟的SMC在血管重塑过程中可以去分化为增殖/合成表型。然而，在体外和体内缺乏直接的证据表明成熟的SMC去分化的特征，SMC和血管干细胞在疾病发展中的相对贡献还没有很好地阐明。在这里，我们的目标是解决这一知识差距。最近，我们在血管壁中发现了一种新型的多潜能血管干细胞(MVSC)。MVSCs表达Sox10和Sox17等转录标志物，可分化为增殖/合成和成熟的SMC。此外，MVSCs还可以分化为多个间充质细胞(软骨、脂肪和成骨)和神经(外周神经元和雪旺细胞)谱系。通过DNA微阵列分析，我们还发现了一个可能调节MVSC增殖和迁移的潜在的MVSC表面标记。此外，通过谱系追踪和生化分析，我们发现MVSCs在培养中超过了SMCs，并且MVSCs在血管损伤后变得增殖，并有助于新生内膜的形成。最后，我们从人动脉粥样硬化斑块、冠状动脉、主动脉和股动脉分离并鉴定了MVSCs。根据我们的初步研究，我们假设MVSC分化是增殖/合成SMC的主要来源，并有助于新生内膜的形成。为了验证我们的假说，我们提出了三个具体的目标：(1)利用谱系追踪模型鉴定MVSC的标志物以及MVSC和成熟的SMC在体外对增殖/合成的SMC的相对贡献；(2)在转基因小鼠模型中确定MVSCs和成熟的SMC在血管损伤后新生内膜形成中的作用；(3)表征人动脉和动脉粥样硬化病变中的MVSCs。如果完成，这项工作将在血管生物学方面开辟新的天地，并展示MVSC分化在血管重塑和疾病发展中的重要作用。这项工作还将深入了解血管重塑的机制，并通过将MVSC作为治疗靶点来开发血管疾病的新疗法。

DESCRIPTION (provided by applicant): Cardiovascular diseases account for 40% of death in United States. Vascular diseases such as atherosclerosis and restenosis involve extensive vascular remodeling such as cell proliferation and migration in neointima. Vascular smooth muscle cells (SMCs) are a major cell type in the tunica media of vascular wall, and it is generally accepted that mature SMCs can de-differentiate into proliferative/synthetic phenotype during vascular remodeling. However, there is a lack of direct evidence that characterize the de-differentiation of mature SMCs in vitro and in vivo, and the relative contribution of SMCs and vascular stem cells to disease development has not been well elucidated. Here we aim to address this knowledge gap. Recently, we have identified a novel type of multipotent vascular stem cells (MVSCs) in the wall of blood vessels. MVSCs express transcriptional markers such as Sox10 and Sox17, and can differentiate into both proliferative/synthetic and mature SMCs. In addition, MVSCs can differentiate into several mesenchymal (chondrogenic, adipogenic and osteogenic) and neural (peripheral neuron and Schwann cell) lineages. By using DNA microarray analysis, we have also identified a potential MVSC surface marker that may regulate MVSC proliferation and migration. Furthermore, by using lineage tracing and biochemical analysis, we have shown that MVSCs outgrow SMCs in culture and that MVSCs become proliferative following vascular injury and contribute to neointima formation. Finally, we have isolated and characterized MVSCs from human atherosclerotic plaques, coronary artery, aorta and femoral artery. Based on our preliminary studies, we hypothesize that MVSC differentiation is a major source of proliferative/synthetic SMCs and contributes to neointima formation. To test our hypothesis, three Specific Aims are proposed: (1) Characterize MVSC markers and the relative contribution of MVSCs and mature SMCs to proliferative/synthetic SMCs in vitro by using lineage tracing models; (2) Determine the roles of MVSCs and mature SMCs in neointima formation following vascular injury in transgenic mouse models; (3) Characterize MVSCs in human arteries and atherosclerotic lesions. If accomplished, this work will break new grounds in vascular biology, and demonstrate the important role of MVSC differentiation in vascular remodeling and disease development. This work will also provide insight into the mechanisms of vascular remodeling and lead to the development of novel therapies for vascular diseases by using MVSC as a therapeutic target.