Role of RPE-derived VEGF in Choroid Development and Stability

RPE 衍生的 VEGF 在脉络膜发育和稳定性中的作用

• 批准号: 7060810
• 负责人: Patricia Ann D'Amore
• 金额: $ 43.06万
• 依托单位: SCHEPENS EYE RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7060810
• 关键词: angiogenesis; biological models; capillary bed; cytoprotection; electron microscopy; genetically modified animals; growth factor receptors; human tissue; immunocytochemistry; kinase inhibitor; laboratory mouse; phosphorylation; polymerase chain reaction; protein isoforms; protein tyrosine kinase; receptor expression; retina circulation; retinal pigment epithelium; small molecule; vascular endothelial growth factors

DESCRIPTION (provided by applicant): Although a significant body of evidence indicates a role for the retinal pigment epithelium in the development and maintenance of the choroidal vasculature, the mechanisms that underlie this relationship are unknown. In addition to an important function in the normal retina, the interactions between RPE and the choroidal vasculature are central to a number of retinal pathologies, including age-related macular diseases (ARMD) such as geographic atrophy. Several findings point to a possible role for vascular endothelial growth factor (VEGF) as a mediator of the RPE cell survival effect on choroidai vessels. Data from experimental models indicate a survival function for VEGF in vessel stabilization, RPE in the adult make VEGF, and choroidal endothelial cells express VEGF receptors, which we show are constitutively activated in the adult. We therefore propose to test the hypothesis that RPE-derived VEGF is necessary for the development and maintenance of the choroidal vasculature by the following aims. (1) To determine the expression pattern of VEGF family members and their receptors (VEGFR1, VEGFR2, VEGFR3, and the neuropilins), and VEGF receptor activation status in the choroid-RPE complex during development and in the adult. (2) To examine the role of VEGF in choroidal vascular development using mice that express only VEGF188, an isoform not normally made by RPE, and mice with an RPE-specific deletion of VEGF. The role of VEGF in the maintenance of the adult choroidal vasculature will be determined by inhibition of the VEGFR2 tyrosine phosphorylation using SU5416, a small molecule VEGFR2-selective tyrosine kinase inhibitor; and interference with the interaction between RPE-derived VEGF and choroidal endothelial VEGFR2 using an inducible DN-VEGFR2 transgenic mouse model. (3) To assess the ability of exogenously added VEGF to "rescue" choroidal loss due to experimentally induced RPE destruction. RPE will be destroyed by systemic administration of sodium iodate (NalO3) and the role of VEGF in trophic effects of RPE on the choroid will be assessed by investigating the ability of exogenously added VEGF to rescue the choroidal loss. Results of these studies will provide mechanistic insight into the means by which RPE support normal choroidal function, and thus may reveal targets for therapeutic intervention into the blinding diseases of macular degeneration.

描述（由申请人提供）：尽管大量证据表明视网膜色素上皮在脉络膜血管系统的发育和维持中发挥作用，但这种关系背后的机制尚不清楚。除了在正常视网膜中发挥重要功能外，RPE 和脉络膜脉管系统之间的相互作用也是许多视网膜病理的核心，包括年龄相关性黄斑疾病 (ARMD)，例如地图样萎缩。多项研究结果表明，血管内皮生长因子 (VEGF) 可能作为脉络膜血管 RPE 细胞存活效应的介质。来自实验模型的数据表明 VEGF 在血管稳定中的生存功能，成人中的 RPE 产生 VEGF，脉络膜内皮细胞表达 VEGF 受体，我们表明这些受体在成人中被组成性激活。因此，我们建议通过以下目标来检验 RPE 衍生的 VEGF 对于脉络膜血管系统的发育和维持所必需的假设。 (1) 确定 VEGF 家族成员及其受体（VEGFR1、VEGFR2、VEGFR3 和神经毡蛋白）的表达模式，以及发育期间和成人脉络膜-RPE 复合体中 VEGF 受体的激活状态。 (2) 使用仅表达 VEGF188（RPE 通常不产生的同工型）的小鼠和 RPE 特异性缺失 VEGF 的小鼠来检查 VEGF 在脉络膜血管发育中的作用。 VEGF 在维持成人脉络膜血管系统中的作用将通过使用 SU5416（一种小分子 VEGFR2 选择性酪氨酸激酶抑制剂）抑制 VEGFR2 酪氨酸磷酸化来确定；并使用可诱导的 DN-VEGFR2 转基因小鼠模型干扰 RPE 衍生的 VEGF 和脉络膜内皮 VEGFR2 之间的相互作用。 (3) 评估外源添加 VEGF“拯救”由于实验诱导的 RPE 破坏而导致的脉络膜丧失的能力。 RPE将通过全身施用碘酸钠(NalO3)而被破坏，并且VEGF在RPE对脉络膜的营养作用中的作用将通过研究外源添加的VEGF拯救脉络膜损失的能力来评估。这些研究的结果将为 RPE 支持正常脉络膜功能的机制提供深入的了解，从而可能揭示治疗干预黄斑变性致盲性疾病的目标。