MT1-MMP-based Animal Model of Age-related Macular Degeneration (AMD)

描述（由申请人提供）：老年性黄斑变性（AMD）是60岁以上老年人致盲的头号原因。AMD的原发损伤发生在视网膜色素上皮（RPE）。AMD有两种形式，干型和湿型，后者与脉络膜新生血管（CNV）有关，导致90%的失明。AMD是一种涉及多基因的复杂疾病。当生物学概念结合起来识别满足多种标准的基因时，表达谱分析是复杂多基因疾病的有力方法。由于光感受器外段（OS）的日常吞噬是RPE的关键功能，而在AMD发病机制中发挥作用的基因可能会显示表达变化，因此我们使用了一种称为CHANGE的自定义表达谱策略来确定满足这两个标准的候选AMD基因。膜型基质金属蛋白酶I （MT1-MMP）是通过该策略发现的一个基因，它显示1)参与OS吞噬，2)与AMD的病理程度相关，3)在另一种视网膜变性（RCS大鼠模型）中增加。建立了MT1-MMP的Tet-On条件过表达转基因小鼠模型，以证实该候选基因的致病潜力。在模型中，强力霉素诱导MT1-MMP过表达，在诱导后的几天内，RPE出现了剧烈的空泡变性、增殖和迁移，导致CNV，类似于AMD的特征。MT1-MMP竞逐AMD因为1)是MMP2的主要催化剂已被证明是增加interphotoreceptor矩阵和chorioneovascular膜的AMD患者,2)是细胞迁移的一个重要中介的内皮细胞在血管的形成,使得CNV相关,3)它让VEGF在湿性AMD已被证明是重要,和4)它对其他各种活动矩阵组件,基质在amd样索斯比眼底营养不良中的重要性已得到证实。因此，我们认为MT1-MMP是AMD重要的新治疗靶点。这项STTR申请代表了与iTherapeutics合作开发我们发现的潜在双重商业利益的项目的第一阶段，即1)AMD脉络膜新生血管模型，其中CNV可以通过简单的给予多西环素来轻松快速地诱导，用于测试各种针对湿型AMD的治疗方法，2)抗mt1 - mmp药物作为AMD的潜在治疗方法。I期的目标将集中在1)以上内容，其中Specific Aim 1，在3个选择的转基因模型株系中选择最佳株系诱导MT1-MMP过表达和表型表达一致性，Specific Aim 2，通过组织学、免疫学和分子分析确认模型中RPE和CNV进行性变性的表型。对于第二阶段，我们将使用我们的模型作为模板，继续执行上述步骤。公共卫生相关性：年龄相关性黄斑变性，尤其是湿型黄斑变性，是60岁以上老年人失明的头号原因。该项目旨在建立一种强大的AMD动物模型，用于湿性AMD治疗方法的测试，并利用它来确定一种新的有效治疗湿性AMD的方法，这与老年人的公共健康密切相关。

DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is the number one cause of blindness for the elderly population over 60. The primary damage in AMD occurs in the retinal pigment epithelium (RPE). There are two forms of AMD, the dry and the wet form, the latter being associated with choroidal neovascularization (CNV) and responsible for 90% of the blindness. AMD is a complex disease involving multiple genes. Expression profiling is a powerful approach to complex multi-gene diseases, when biological concepts are combined to identify genes fulfilling multiple criteria. Since daily phagocytosis of photoreceptor outer segments (OS) is a key function of RPE, and genes that play a role in the pathogenesis of AMD would be expected to show expression changes, we used a custom expression profiling strategy called CHANGE to identify candidate AMD genes fulfilling both criteria. Membrane-type matrix metalloproteinase I (MT1-MMP) was a gene identified by this strategy that showed 1) involvement in OS phagocytosis, 2) increase that correlated with the degree of pathology in AMD, and 3) increase in another retinal degeneration, the RCS rat model. A Tet-On conditional over-expression transgenic mouse model of MT1-MMP was constructed to confirm the pathogenic potential of this candidate gene. Induction of MT1-MMP over-expression by doxycycline administration in the model demonstrated dramatic vacuolar degeneration, proliferation, and migration of RPE, leading to CNV, resembling characteristics seen in AMD, within days of induction. MT1-MMP is a plausible candidate for AMD since 1) it is the primary activator of MMP2 which has been shown to be increased in the interphotoreceptor matrix and chorioneovascular membranes of AMD patients, 2) it is an important mediator of cellular migration for endothelial cells in blood vessel formation, making it relevant to CNV, 3) it up-regulates VEGF which has been shown to be important in wet AMD, and 4) it has activities against various other matrix components, and the importance of matrix has been demonstrated in AMD-like Sorsby's fundus dystrophy. Thus, we believe MT1-MMP to be an important new therapeutic target for AMD. This STTR application represents the Phase I of a project to develop in collaboration with iTherapeutics the potential dual commercial benefit of our discovery, namely 1) a model of AMD choroidal neovascularization in which the CNV can be easily and quickly induced by a simple administration of doxycycline for testing of various therapeutics against the wet form of AMD, and 2) anti-MT1-MMP agents as potential therapeutics for AMD. The aims for Phase I will focus on 1) above with Specific Aim 1, to select the best line of the transgenic model among the 3 selected lines for induction of MT1-MMP over-expression and consistency of phenotypic expression, and Specific Aim 2, to confirm the phenotype of progressive degeneration of RPE and CNV in the model through histological, immunological, and molecular analyses. For Phase II, we will pursue 2) above, using our model as a template. PUBLIC HEALTH RELEVANCE: Age-related macular degeneration, especially the wet form, is the number one cause of blindness for the elderly population over 60. This project whose aim is to develop a powerful animal model of AMD that can be used for testing of therapeutics for wet AMD and to use it to identify a new effective therapeutic for wet AMD is highly relevant to public health of the elderly.