Investigation of endomucin as a novel regulator of angiogenesis

摘要 血管生成，即新血管的生长，是发育、伤口愈合， 和生殖以及一些病理学。异常视网膜血管生成导致视力丧失， 一系列眼部病理学，包括糖尿病视网膜病变、湿性黄斑变性和视网膜病变， 早产内粘蛋白（endomucin，EMCN）是一种由内皮细胞特异性表达的粘蛋白样糖蛋白， 静脉和毛细血管我们的初步研究揭示了EMCN在调节VEGF诱导的细胞凋亡中的作用。 在体外内皮功能和在体内正常血管生成中。使用siRNA减少EMCN表达 导致VEGF刺激的体外内皮细胞增殖、迁移和管形成减少， 体内视网膜血管化。本申请旨在检验EMCN在以下方面发挥作用的假设： VEGF诱导的病理性新血管形成，EMCN通过以下途径影响VEGF刺激的功能： 调制其信号。研究概述了EMCN在病理性血管生成中的作用， 模型的异常视网膜和脉络膜血管生长，以及了解分子 EMCN对VEGF诱导的内皮细胞功能的作用机制。 目的1中的研究将检查EMCN在病理性眼部病变发展中的作用。 体内新血管形成。氧诱导的视网膜新生血管模型和激光诱导的 脉络膜新血管形成的模型将与功能获得和丧失研究结合使用， 在ICAM 2的控制下，使用siRNA和慢病毒递送的shEMCN， 启动子以及ICAM 2控制下的adEMCN。EMCN敲除的效果和 将定量过表达对病理性血管生长的影响。目的2提出阐明分子 EMCN在VEGF诱导的内皮功能调节中的作用机制。研究使用 将使用EMCN缺失突变体来确定EMCN的作用是否在细胞表面介导。 EMCN在细胞表面的作用将通过检测其对VEGF结合的影响来进一步研究， VEGFR2稳定化/内化。细胞内效应将集中在EMCN的可能作用 磷酸化，EMCN对VEGFR2磷酸酶活性的影响以及鉴定潜在的 EMCN细胞内结合伴侣。这些拟议研究的结果将使人们更好地了解 EMCN在正常和病理性血管生成中的作用，并可能导致新的内皮细胞的发展。 用于抑制血管生长的细胞特异性疗法。 !

ABSTRACT Angiogenesis, the growth of new blood vessels, is an important component of development, wound healing, and reproduction as well as a number of pathologies. Abnormal retinal angiogenesis leads to vision loss in a range of ocular pathologies including diabetic retinopathy, wet macular degeneration, and the retinopathy of prematurity. Endomucin (EMCN) is a mucin-like glycoprotein specifically expressed by endothelial cells of veins and capillaries. Our preliminary studies reveal a role for EMCN in the regulation of VEGF-induced endothelial functions in vitro and in normal angiogenesis in vivo. Reduction of EMCN expression using siRNA led to decreased VEGF-stimulated endothelial proliferation, migration and tube formation in vitro, and impaired retinal vascularization in vivo. This application proposes to test the hypothesis that EMCN plays a role in VEGF-induced pathologic neovascularization and that EMCN influences VEGF-stimulated functions by modulating its signaling. Studies are outlined to examine the role of EMCN in pathological angiogenesis using models of abnormal retinal and choroidal blood vessel growth as well as to understand the molecular mechanism that underlies EMCN's effects on VEGF-induced endothelial cell functions using in vitro systems. Studies in Aim 1 will examine the role of EMCN in the development of pathologic ocular neovascularization in vivo. The oxygen-induced model of retinal neovascularization and the laser-induced model of choroidal neovascularization will be utilized in conjunction with both gain and loss of function studies, using both siRNA and lentivirally-delivered shEMCN under the control of ICAM2, an endothelial-specific promoter, as well as adEMCN under the control of ICAM2. The effect of EMCN knockdown and overexpression on pathologic vessel growth will be quantified. Aim 2 proposes to elucidate the molecular mechanism of EMCN's role in the regulation of VEGF-induced endothelial functions. Studies using EMCN deletion mutants will be employed to determine if the effects of EMCN are mediated at the cell surface. The role of EMCN at the cell surface will be further investigated by examining its effect on VEGF binding and VEGFR2 stabilization/internalization. Intracellular effects will focus on a possible role of EMCN phosphorylation, the effect of EMCN on VEGFR2 phosphatase activity as well as the identification of potential EMCN intracellular binding partners. Results of these proposed studies will provide a better understanding of the role of EMCN in normal and pathologic angiogenesis and may lead to the development of novel endothelial cell-specific therapies for the suppression of vessel growth. !