TYROSINE PHOSPHATASES IN ENDOTHELIAL GROWTH CONTROL

确定调节血管生成和血管生成血管生长的内在分子控制有望为实体瘤、糖尿病视网膜病变、关节炎、皮肤和其他疾病的治疗提供靶点。 微血管完整性的发育组装、重塑和维持是由内皮细胞对局部环境信号的反应通过表面受体转导来调节的动态过程。 成熟血管中内皮的基本性质之一是增殖的细胞环境依赖性约束。 我们提出了一个假设，即内皮受体酪氨酸磷酸酶，ECRTP/CD 148，转导细胞生长停滞信号对阿曲他克林接触的反受体。 特异性结合ECRTP/CD 148胞外域序列的单克隆抗体ECRTP.ab1将其表达定位于肾和其他组织中的动脉和毛细血管内皮。内皮祖细胞在并入发育中的肾肾小球毛细血管之前表达ECRTP/CD 148，并且ECRTP/CD 148在内皮间接触点处积累。 二价形式的ECRTP.ab1阻断培养的内皮细胞增殖和迁移，在小鼠角膜试验中抑制血管生成，并促进细胞内酪氨酸磷蛋白的去磷酸化。缺陷细胞系中ECRTP/CD 148的表达赋予依赖于内在酪氨酸磷酸酶活性的抗体诱导的生长抑制。 目前的提案描述了以下计划：1）确定CD 148的功能性反受体，2）确定ECRTP/CD 148的细胞内底物及其在内皮生长停滞中的作用，3）确定ECRTP/CD 148在血管发育过程中的功能。 同源重组ES系和小鼠将确定ECRTP/CD 148在发育血管组装中的功能。 这些研究将扩展调节血管生成的分子控制的定义，并将定义新的抗血管生成治疗的分子靶点。

Definition of the intrinsic molecular controls that regulate angiogenic and vasculogenic blood vessel growth promises to provide targets for therapy of solid tumors, diabetic retinopathy, arthritis, skin and other diseases. Developmental assembly, remodeling and maintenance of microvascular integrity are dynamic processes regulated by endothelial responses to local environmental cues, transduced through surface receptors. One of the properties fundamental to endothelium in mature vessels is cell context dependent constraints over proliferation. We have advanced the hypothesis that an endothelial receptor tyrosine phosphatase, ECRTP/CD148, transduces cell growth arrest signals on juxtacrine contact with a counter-receptor. A monoclonal antibody, ECRTP.ab1, that specifically binds ECRTP/CD148 ectodomain sequences localizes its expression to endothelium of arteries and capillaries in kidney, and other tissues. Endothelial progenitor cells express ECRTP/CD148 prior to their incorporation into developing glomerular capillaries of kidney, and ECRTP/CD148 accumulates at inter-endothelial points of contact. Bivalent forms of ECRTP.ab1 block cultured endothelial cell proliferation and migration, inhibit angiogenesis in a mouse corneal assay, and promote dephosphorylation of intracellular tyrosine phosphoproteins. Expression of ECRTP/CD148 in deficient cell lines confers antibody-induced growth inhibition that is dependent upon intrinsic tyrosine phosphatase activity. The current proposal describes plans to: 1) define a functional counter-receptor to CD148, 2) to identify intracellular substrates of ECRTP/CD148 and their role in endothelial growth arrest, and 3) to define ECRTP/CD148 function during vascular development. Homologous recombinant ES lines and mice will define function of ECRTP/CD148 in developmental vascular assembly. These studies will extend definition of molecular controls regulating angiogenesis, and will define new molecular targets for anti-angiogenic therapies.