Role of fibronectin in vascular plexus self-organization during embryogenesis

描述（申请人提供）：中胚层祖细胞形成血管，血管发生，是胚胎发育和某些病理生理共同的基本过程。最近我们发现，从孤立的成血管细胞簇形成血管索涉及广泛的侵入性活动。在这个过程中，一组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。我们的目的是确定纤维连接蛋白及其主要内皮受体在这一过程中的具体作用。具体来说，我们将(1)确定纤维连接蛋白是否在血管生成发芽过程中起指导作用，(2)研究细胞介导的宏观组装动力学和原始内皮细胞索周围富含纤维连接蛋白的瞬时细胞外基质的周转，(3)确定细胞粘附复合物的分子组成以及整合素avb3和a5b1的各自作用，以及(4)将实验数据综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绿色荧光蛋白结构的组合在体内研究血管源性发芽。该项目的长期目标是充分了解内皮细胞- ecm相互作用的细节，以便为组织工程或理解发育形态发生过程构建预测定量模型。

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.