Role of fibronectin in vascular plexus self-organization during embryogenesis

描述(由申请人提供)：由中胚层前体细胞形成血管是胚胎发育和某些病理生理学共同的基本过程。最近，我们发现，从分离的血管母细胞簇形成血管索涉及到广泛的侵袭活动。在这个血管生成萌芽的过程中，一群内皮细胞侵入数百微米的无血管区域，从而奠定了原始血管丛的结构。我们的目标是确定纤维连接蛋白及其主要内皮受体在这一过程中的特定作用。具体地说，我们将(1)确定纤维连接蛋白在血管生成萌发过程中是否起到指导作用，(2)研究原始内皮细胞束周围瞬时的、富含纤维连接蛋白的细胞外基质的大组装动力学和周转，(3)确定细胞黏附复合体的分子组成以及整合素avb3和a5b1的各自作用，以及(4)将实验数据合成血管生成的定量模型。在存在或不存在干扰试剂的情况下，将通过自动光学显微镜和荧光标记抗体和GFP构建物的组合，在体内研究血管生成萌发。该项目的长期目标是充分详细地了解内皮细胞与细胞外基质的相互作用，以便构建可预测的定量模型，无论是用于组织工程，还是理解发育的形态发生过程。 了解血管发育具有压倒性的临床重要性。我们的目标，以及其他血管生物学家的目标，是解释促进或抑制血管生长的机制，从而调节血管网络结构。特别是，内皮祖细胞是治疗性血管形成策略、组织工程和试图阻止肿瘤生长的重点。

DESCRIPTION (provided by applicant): Vessel formation from mesodermal progenitors, vasculogenesis, is a fundamental process common to both embryonic development and certain pathophysiologies. Recently we showed that the formation of vascular cords from isolated clusters of angioblasts involves extensive invasive activity. During this process, vasculogenic sprouting, a group of endothelial cells invades hundreds of micrometers into avascular areas, and thereby lays down the structure of the primordial vascular plexus. We aim to determine the specific role of fibronectin, and its major endothelial receptors in the process. Specifically, we will (1) determine if fibronectin acts as a guidance cue during vasculogenic sprouting, (2) study the cell-mediated macro- assembly dynamics and turnover of the transient, fibronectin-rich extracellular matrix surrounding the cords of primordial endothelial cells, (3) determine the molecular composition of cell adhesion complexes and the respective roles of integrins avb3 and a5b1, and (4) synthesize the experimental data into a quantitative model of vasculogenesis. Vasculogenic sprouting will be studied in vivo, through automated optical microscopy and a combination of fluorescence-tagged antibodies and GFP constructs, in the presence or absence of perturbing reagents. The long term goal of the project is to understand endothelial cell-ECM interactions in sufficient detail to allow the construction of predictive quantitative models, either for tissue engineering, or to understand developmental morphogenetic processes. Understanding blood vessel development is of overwhelming clinical importance. Our goal, and the goal of other vascular biologists, is to explain the mechanisms that promote or inhibit vessel growth and thus regulate the structure of the vessel network. In particular, endothelial progenitors are in the focus of therapeutic vascularization strategies, tissue engineering, and attempts to block tumor growth.