ICAM-1 governs angiogenesis and endothelial redox status

描述（由申请人提供）：刺激血管生成涉及内皮细胞从静止到有丝分裂和亲迁移表型的转变。内皮细胞运动的协调调节是这一现象的一个整体过程。然而，内皮细胞定向迁移的具体分子机制仍不清楚。VEGF（164）通过激活包括PI3K、Akt和eNOS在内的多种细胞通路，是内皮细胞迁移的有效介质。最近的研究表明，VEGF（164）刺激增加了粘附分子的表达，如细胞间粘附分子-1 （ICAM-1）的表达，其可能参与了VEGF介导的内皮细胞迁移。然而，关于黏附分子调控血管生成的机制还缺乏详细的信息。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）对PTEN磷酸酶的氧化还原调控VEGF（164）血管生成活性，调节内皮细胞NOS活性和细胞内定位的假说。这一假设将通过以下具体目标进行检验：1)确定ICAM-1如何调节GCL-C功能并检查GSH如何影响VEGF（164) ROS的产生，2)确定ICAM-1如何控制eNOS细胞定位和活性以响应VEGF（164）刺激，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。从这些目标中积累的数据将为在VEGF（164）介导的血管生成和内皮细胞趋化过程中，ICAM-1在控制内皮谷胱甘肽代谢、eNOS活性和生物利用度以及PTEN活性中的作用提供独特的见解。该项目的完成将大大促进我们对炎症粘附分子调节血管生成的具体机制的理解，并确定治疗性血管生成干预的新靶点。

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.