ICAM-1 governs angiogenesis and endothelial redox status

描述(申请人提供)：血管生成的刺激涉及内皮细胞从静止到有丝分裂和支持迁移的表型的转变。在这一现象中，内皮细胞运动的协调调节是一个不可或缺的过程。然而，负责内皮细胞定向迁移的特定分子机制仍未得到很好的描述。血管内皮细胞生长因子(164)通过激活PI3K、Akt和eNOS等多种细胞信号通路，有效地调节内皮细胞的迁移。最近的研究表明，血管内皮细胞生长因子(164)的刺激增加了黏附分子的表达，如细胞间黏附分子-1(ICAM-1)的表达，这可能参与了血管内皮细胞的迁移。然而，关于黏附分子调控血管生成的详细机制的信息还很少。因此，本研究将探讨ICAM-1通过负调控谷氨酸半胱氨酸连接酶(GCL-C)和随后的谷胱甘肽(GSH)氧化还原调节PTEN磷酸酶来调控血管生成活性，并调控内皮细胞一氧化氮合酶活性和细胞内定位的假说。这一假说将通过以下具体目标得到验证：1)确定ICAM-1如何调节GCL-C功能，并研究GSH如何影响VEGF(164)ROS的产生；2)确定ICAM-1如何调控eNOS细胞对VEGF(164)刺激的定位和活性；以及3)确定细胞内GSH水平的增加如何影响PTEN对VEGF(164)信号的调节。从这些目标积累的数据将提供独特的洞察ICAM-1在调控内皮细胞谷胱甘肽代谢、eNOS活性和生物利用度，以及在血管内皮生长因子(164)介导的血管生成和内皮细胞趋化过程中PTEN活性的作用。该项目的完成将极大地促进我们对炎性黏附分子调节血管生成的具体机制的理解，并为治疗性血管生成干预寻找新的靶点。

DESCRIPTION (provided by applicant): Stimulation of angiogenesis involves the transition of endothelial cells from a quiescent to mitogenic and pro-migratory phenotype. Coordinate regulation of endothelial cell motility is an integral process in this phenomenon. However, specific molecular mechanisms responsible for directional migration of endothelial cells remain poorly characterized. VEGF(164) is a potent mediator of endothelial cell migration through activation of various cellular pathways including PI3K, Akt, and eNOS. Recent studies demonstrate that VEGF(164) stimulation increases adhesion molecule expression, such as intercellular adhesion molecule-1 (ICAM-1) expression, which may participate in VEGF mediated endothelial cell migration. However, there is a paucity of information detailing mechanisms of adhesion molecule regulation of angiogenesis. Therefore, this proposal will investigate the hypothesis that ICAM-1 governs VEGF(164) angiogenic activity by negatively regulating glutamate cysteine ligase (GCL-C) and subsequent glutathione (GSH) redox regulation of PTEN phosphatase, and modulates endothelial NOS activity and intracellular localization. This hypothesis will be examined by the following specific aims: 1) determine how ICAM-1 modulates GCL-C function and examine how GSH affects VEGF(164) ROS production, 2) determine how ICAM-1 governs eNOS cellular localization and activity in response to VEGF(164) stimulation, and 3) determine how increased intracellular levels of GSH affect PTEN regulation of VEGF(164) signaling. Data accumulated from these aims will provide unique insight into the role of ICAM-1 in controlling endothelial glutathione metabolism, eNOS activity and bioavailability, and PTEN activity during VEGF(164) mediated angiogenesis and endothelial cell chemotaxis. Completion of this project will significantly advance our understanding of specific mechanisms by which inflammatory adhesion molecules regulate angiogenesis and identify new targets for therapeutic angiogenic intervention.