DIFFERENTIATION OF MOUSE YOLK SAC ENDOTHELIAL CELLS

建议研究分析几个离散的步骤，通过这些步骤 大多数原始的内皮细胞前体在哺乳动物中可以 胚胎发育，产生各种血管，组成 新生器官的微血管构筑。这些步骤被认为是 包括：1)假想的造血性血管母细胞的出现 干细胞产生了不同的血液循环谱系 血液，以及生成血管的血管母细胞。血管母细胞是 首先在胚胎外卵黄囊中检测到它们，在那里它们可以被显示 结合形成第一批可见的微血管。虽然 随后，初始血管可能会分支并穿透不同的 器官雏形(血管生成)，大量的血管母细胞迁移 作为个体细胞转化为发育中的器官雏形参与其中 特定微血管床的形成(血管生成)。为了什么？ 在一定程度上也有分化和招聘的局部兴起 间充质细胞在不同器官微血管形成中的作用 地点尚不清楚。 来研究事件发生的顺序 微血管实验的目的是： 1.鉴定和分离卵黄囊血管母细胞； B.根据这些血管母细胞的细胞表面来描述它们的特征 表型，对生长因子的反应，特定的激酶和表达 细胞因子的合成； C.开发方法，允许血管母细胞在没有 分化，从而建立血管母细胞系； D.建立允许血管母细胞形成三维结构的方法 试管或通畅的血管。 A.确定肺组织中出现的特异性属性。 发育中的肺原基由卵黄囊血管母细胞(1a或1c； 血管生成)或被卵黄囊微血管穿透(1D；血管生成) B.类似地决定心肌分化的模式 心脏发育过程中的相关微血管 C.勾勒出大脑特定属性在 前脑/大脑发育中的微血管构筑 3.利用上述产生的信息，分析最早出现的情况 内细胞团细胞中血管母细胞的特性 早期胚胎或由胚胎干细胞(ES细胞)前体生成。 总而言之，这些研究将提供一个关于器官特异性的图景 哺乳动物胚胎中存在微血管的异质性。 对这一过程的理解可能会导致制定战略 选择性地增强或抑制血管形成，并提供 对这种特殊的血管分化的洞察 随着炎症、肿瘤的建立，其发病机制广泛 一系列血管新生疾病。

Studies are proposed to analyze the several discrete steps by which the most primitive precursors of endothelial cells can, during mammalian embryonic development, generate the diverse blood vessels that comprise the microvasculature of the emerging organs. These steps are believed to include: 1) the emergence from postulated hemangioblasts of hematopoietic stem cells which give rise to tahe various lineages of the circulating blood, and angioblasts which give rise to blood vessels. Angioblasts are first detectable in the extraembryonic yolk sac where they can be shown to coalesce to give rise to the first visible microvessels. Although subsequently the initial blood vessels may branch and penetrate different organ rudiments (angiogenesis), a significant number of angioblasts migrate as individual cells into developing organ rudiments to participate there in the formation of specific microvascular beds (vasculogenesis). To what extent there is also differentiation and recruitment of locally arising mesenchymal cells in the formation of the microvessels in different organ sites is not known. To study the sequence of events underlying the development of the microvasculature experiments are proposed to: 1. a. Identify and isolate yolk sac angioblasts; b. Characterize these angioblasts in terms of their cell surface phenotype, response to growth factors, expression of specific kinases and synthesis of cytokines; c. Develop methods that permit angioblast proliferation without differentiation, thus establishing angioblast cell lines; d. Establish methods that permit angioblasts to form three-dimensional tubes or patent vessels in vitro. 2. a. determine the emergence of lung-specific properties in the developing lung rudiment seeded by yolk sac angioblasts (1a or 1c; vasculogenesis) or penetrated by yolk sac microvessels (1d; angiogenesis) b. similarly determine the pattern of differentiation of myocardium associated microvessels during heart development c. delineate the appearance of brain-specific properties in the developing microvasculature of the forebrain/cerebrum 3. analyze, using the information generated above, the earliest emergence of angioblast-specific properties in cells from the inner cell mass of the early embryo or generated from embryonic stem cell (ES cell) precursors. Together, these studies will provide a picture of how organ-specific heterogeneity of the microvasculature occurs in the mammalian embryo. Understanding of this process may lead to development of strategies for selective augmentation or inhibition of blood vessel formation and provide insight into such specialized vascular differentiations as those associated with inflammation, establishment of tumors, or the pathogenesis of a wide array of angiogenic diseases.