Extracellular Proteinases in Ocular Neovascularization

描述（由申请人提供）：视网膜新生血管是美国工作年龄成人（糖尿病视网膜病变）和婴儿（早产儿视网膜病变）致盲的主要原因。血管生成级联反应的一个重要事件是毛细血管基底膜的破裂和微血管内皮细胞通过细胞外基质的侵入和迁移。血管生成的这一步骤部分取决于蛋白酶的表达和活性，包括尿激酶（uPA）及其受体。该酶的活性受特异性内源性抑制剂纤溶酶原激活物抑制剂派-1的调节。派-1在新血管形成期间在视网膜中升高，并且似乎是新生血管反应所需的。血管生成的起始以及蛋白酶和抑制剂表达的刺激受特异性生长因子（包括众所周知的血管内皮生长因子（VEGF））的活性调节。其他因素可能在此过程中发挥重要作用，包括肝细胞生长因子（HGF），其在眼部血管生成中的功能很少受到关注。了解蛋白酶，蛋白酶抑制剂和生长因子的表达机制，并确定其功能的特异性抑制剂，可能会为视网膜新生血管的新的治疗干预措施的发展提供独特的机会。该建议将测试视网膜新生血管化是由特定生长因子、细胞外蛋白酶及其抑制剂的表达促进的假设，抑制这些生长因子、细胞外蛋白酶及其抑制剂可能导致新的和有用的治疗。本研究的主要目的是：（1）研究派-1在视网膜新生血管形成中的表达及作用。我们将使用生物化学，组织学和分子技术，包括使用基因敲除动物来实现这一目标。(2)目的探讨肝细胞生长因子（HGF）在视网膜新生血管形成过程中对视网膜毛细血管内皮细胞行为和蛋白酶表达的调控作用。研究将集中在HGF在野生型和转基因动物中调节蛋白酶表达和内皮细胞行为的作用。(3)确定是否可以通过使用直接或间接抑制派-1或HGF功能的试剂来抑制视网膜新生血管形成的程度。这些研究的结果将使我们能够进一步确定视网膜中新血管形成的机制，这可能导致严重的视觉并发症，以及血管生成过程的特定阶段是否是治疗干预的适当目标。这种方法将提供一个合理的基础上，开发潜在的强大和有效的治疗眼部新生血管。

DESCRIPTION (provided by applicant): Retinal neovascularization is the leading cause of blindness in the United States among working-age adults (diabetic retinopathy) and infants (retinopathy of prematurity). An important event of the angiogenesis cascade is the breakdown of the capillary basement membrane and the invasion and migration of microvascular endothelial cells through the extracellular matrix. This step of angiogenesis is partially dependent upon the expression and activity of proteinases, including urokinase (uPA) and its receptor. The activity of this enzyme is regulated by specific endogenous inhibitor, plasminogen activator inhibitor PAI-1. PAI-1 is elevated in the retina during new vessel formation and appears to be required for the neovascular response. The initiation of angiogenesis and the stimulation of proteinase and inhibitor expression are regulated by the activity of specific growth factors including the well known vascular endothelial growth factor (VEGF). Other factors may play important roles during this process including the hepatocyte growth factor (HGF) which has received little attention in terms of its function in ocular angiogenesis. Understanding the mechanisms of proteinase, proteinase inhibitor and growth factor expression, and identifying specific inhibitors of their functions may provide unique opportunities for the development of new therapeutic interventions for retinal neovascularization. This proposal will test the hypothesis that retinal neovascularization is facilitated by the expression of specific growth factors, extracelluar proteinases and their inhibitors, the inhibition of which may lead to new and useful therapies. The aims of this study which will address the hypothesis are: (1) To characterize the expression and role of PAI-1 in retinal neovascularization. We will use biochemical, histological and molecular techniques, including the use of knockout animals to address this aim. (2) To determine the expression and role of hepatocyte growth factor (HGF) in the regulation of proteinase expression and retinal capillary endothelial cell behavior in retinal neovascularization. Studies will focus on the role of HGF in regulating proteinase expression and endothelial cell behavior using wildtype and transgenic animals. (3) To determine if the extent of retinal neovascularization can be suppressed through the use of agents which directly or indirectly inhibit the function of PAI-1 or HGF. The results of these studies will allow us to further define the mechanisms involved in the formation of new vessels in the retina which can lead to serious visual complications, and whether a specific stage of the angiogenic process is an appropriate target for therapeutic intervention. Such an approach will provide a rational basis for the development of potentially powerful and effective therapeutics for ocular neovascularization.