PECAM-1 AND REGULATION OF ANGIOGENESIS

描述(改编自研究人员摘要)：血管生成，高度 新的毛细血管形成的调节过程在正常成年人中很少发生， 但在胚胎发育、黄体形成和伤口形成过程中是必需的。 治愈。不受控制的血管生成在疾病中扮演着重要的角色 类风湿性关节炎、血管瘤、肿瘤生长和转移。发展中的 抑制血管生成的有效药物在肿瘤治疗中具有潜在价值。 这些疾病的治疗。凝血酶敏感蛋白1(TS1)和某些多肽 三七总皂甙可阻断体内血管生成，抑制肿瘤细胞增殖。 内皮细胞(ECs)在体外的迁移。这些调查人员已经证明 TS I是EC表型的主要调节因子，其表达充足 恢复多发性瘤的正常表型和抑制血管瘤的形成 中T转化小鼠脑内皮细胞。这至少在一定程度上是通过 完全抑制血小板内皮细胞黏附分子-I (PECAM-1)表达，是EC黏附和血管生成的重要调节因子。 这项建议的主要目标是划定表达和粘合 不同PECAM-I亚型的功能及其信号转导特征 内皮细胞中的通路。TS I和PECAM-I亚型的表达模式为 用原位杂交法检测发育中的小鼠血管内皮细胞 免疫组织化学。不同PECAM-I亚型和/或其亚型的表达 内皮细胞中的细胞质嵌合体将决定不同的亚型是否具有 在EC表型调节中的不同角色，并需要与 细胞质蛋白。GST-PECAM-I胞质融合蛋白 酪氨酸、丝氨酸和苏氨酸残基上的磷酸化将是 在下拉实验中用于识别信号转导分子 与PECAM-1相互作用。标记的PECAM-I或His-myc亚型的表达 上皮细胞模型(MDCK细胞)中的细胞质结构域，它形成 附着点非常类似于EC，将说明它们是否会影响 粘附性连接的形成及其对PECAM-I细胞粘附性的影响 信令功能。这些研究将提供对协调一致的 TS-1和PECAM-1异构体的表达及其相互作用 调控EC表型。胞内蛋白的特性 与PECAM-I胞质结构域的相互作用将提供进一步的知识 调节PECAM-I黏附功能的信号通路。它是 建议可以通过利用这些资源来获得治疗益处 控制血管过度血管化特征的信号通路 关节炎。

DESCRIPTION (Adapted from Investigator's abstract): Angiogenesis, the highly regulated process of new capillary formation rarely occurs in normal adults, but is necessary during embryogenesis, corpus luteum formation, and wound healing. Uncontrolled angiogenesis plays an important role in diseases such as rheumatoid arthritis, hemangiomas, tumor growth and metastasis. Development of effective agents which can inhibit angiogenesis has potential value in the treatment of these diseases. Thrombospondin 1 (TS1) and certain peptides derived from TS I block angiogenesis in vivo and inhibit the proliferation and migration of endothelial cells (ECs) in vitro. These investigators have shown that TS I is a major regulator of EC phenotype and its expression is sufficient to restore a normal phenotype and suppress hemangioma formation in Polyoma middle T transformed mouse brain ECs. This is mediated, at least in part, by complete suppression of platelet endothelial cell adhesion molecule- I (PECAM-1) expression, an important regulator of EC adhesion and angiogenesis. The main objective of this proposal is to delineate the expression and adhesive function of different PECAM- I isoforms and to characterize their signaling pathways in ECs. The expression pattern of TS I and PECAM- I isoforms will be examined in ECs of developing murine blood vessels by in situ hybridization and immunohistochemistry. Expression of different PECAM- I isoforms and/or their cytoplasmic chimeras in ECs will determine whether different isoforms have distinct roles in regulation of EC phenotype and require interactions with cytoplasmic proteins. The GST-PECAM- I cytoplasmic fusion proteins phosphorylated on their tyrosine, serine, and threonine residues will be utilized in pull down experiments to identify the signal transducing molecules which interact with PECAM- 1. Expression of PECAM- I isoforms or his-myc tagged cytoplasmic domains in an epithelial cell model (MDCK cells), which forms adherens junctions very similar to ECs, will illustrate whether they affect formation of adherens junctions and influence PECAM- I cellular adhesive and signaling functions. These studies will provide insight into the coordinated expression of TS 1 and PECAM- 1 isoforms and their interactive roles in regulating EC phenotype. Characterization of the intracellular proteins which interact with PECAM- I cytoplasmic domains will provide further knowledge of the signaling pathways which regulate PECAM- I adhesive functions. It is suggested that a therapeutic benefit can be derived by exploiting these signaling pathways to control the hypervascularization characteristic of arthritis.