PECAM-1 AND REGULATION OF ANGIOGENESIS

描述（改编自研究者摘要）：血管生成，高度 新毛细血管形成的调节过程很少发生在正常成人中， 但在胚胎发生、黄体形成和创伤过程中是必需的 治愈不受控制的血管生成在疾病中起重要作用， 类风湿性关节炎、血管瘤、肿瘤生长和转移。发展 有效的抑制血管生成的药物具有潜在的应用价值， 这些疾病的治疗。血小板反应蛋白1（TS 1）和某些肽 来源于TS I的化合物在体内阻断血管生成并抑制增殖， 内皮细胞（EC）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，其表达足够 恢复正常表型并抑制多瘤性血管瘤形成 中T转化的小鼠脑EC。这至少部分是由以下因素介导的： 完全抑制血小板内皮细胞粘附分子- I （PECAM-1）表达，其是EC粘附和血管生成的重要调节剂。 该提案的主要目的是划定表达和粘合剂 不同PECAM-I同种型的功能并表征它们的信号传导 在ECs中的路径。TS I和PECAM-I同种型的表达模式将是 通过原位杂交在发育中的小鼠血管的EC中检查， 免疫组化不同PECAM-I同种型和/或它们的表达 EC中的细胞质嵌合体将决定不同的同种型是否具有 在EC表型调节中的不同作用，需要与 胞质蛋白GST-PECAM- I胞浆融合蛋白 在它们的酪氨酸、丝氨酸和苏氨酸残基上磷酸化的蛋白质将被 用于下拉实验以鉴定信号转导分子 与PECAM- 1相互作用。PECAM-I同种型或his-myc标记的表达 上皮细胞模型（MDCK细胞）中的胞质结构域， 粘附连接非常类似于EC，将说明它们是否影响 粘附连接的形成并影响PECAM-1细胞粘附和 信号功能。这些研究将提供深入了解协调 TS 1和PECAM- 1亚型的表达及其在 调节EC表型。细胞内蛋白质的表征， 与PECAM-I胞质结构域相互作用将提供关于 调节PECAM-1粘附功能的信号通路。是 建议通过利用这些可以获得治疗益处， 信号通路来控制血管过度增生的特点 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.