Murine Age-related Macular Degeneration: Model of Known Human Risk Factors

描述（由申请人提供）：年龄相关性黄斑变性（AMD）是一种迟发性、进行性、神经退行性疾病，对老年人具有破坏性影响。这种疾病主要发生在65岁以上的人群中，约占西欧和北美登记失明人数的50%。AMD表现为“干”（萎缩性）或“湿”（渗出性）。AMD的发病机制显然是多因素的，遗传和环境因素，包括年龄、吸烟、饮食、性别、氧化应激和炎症在发病和发展中起作用。我们最近开发了一种AMD的小鼠模型，结合了AMD的三个危险因素：高龄，载脂蛋白E [apoE（蛋白）；人类APOE（基因）异构体的表达和暴露于高脂肪，高胆固醇（HF-C）饮食。这些小鼠的病理变化与干性和湿性AMD的形态学特征相似，包括厚的弥漫性视网膜下色素上皮（RPE）沉积、富含脂质的样物质沉积、Bruch膜增厚、RPE萎缩的斑块区覆盖光感受器变性和脉络膜新生血管（CNV）。重要的是，这些变化需要所有三个风险因素的存在。这种自发发生的CNV动物模型首次纳入了人类疾病的生理相关危险因素。在本提案中，我们的目标是开发和建立这种AMD的动物模型，超越其目前记录的历史，以记录表型的可重复性；将RPE、Bruch膜和脉络膜的变化与光感受器的退行性作用联系起来，并确定导致这些变化的分子途径。我们希望阐明该模型中发生的变化的发病机制将有助于我们了解导致AMD神经病理的未知分子机制。为此，我们提出了三个具体目标：(1)确定长期暴露于HF-C饮食是否会增加AMD小鼠模型中自发性CNV和亚rpe沉积形成的严重程度；(2)以光感受器为重点，检查和评估APOE小鼠视网膜的退行性和突触变化；(3)利用比较微阵列表达谱技术，鉴定这些apoE小鼠眼睛中RPE、脉络膜和视网膜中调控沉积物和CNV形成通路的基因。对这些动物的分析将提供对AMD发病机制的深入了解，以及分离特定危险因素的相对贡献和退行性影响的手段。

DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is a late-onset, progressive, neurodegenerative disease with devastating impact on the elderly. This disease occurs primarily in people over the age of 65 years and accounts for approximately 50% of registered blindness in Western Europe and North America. AMD develops as either "dry" (atrophic) or "wet" (exudative). The pathogenesis of AMD is clearly multifactorial with genetic and environmental factors including aging, smoking, diet, gender, oxidative stress, and inflammation playing roles in onset and progression. We have recently developed a murine model of AMD by combining three of the risk factors for AMD: advanced age, apolipoprotein E [apoE (protein); human APOE (gene)] isoform expression and exposure to a high- fat, high-cholesterol (HF-C) diet. These mice develop pathological changes similar to the morphologic hallmarks observed in dry and wet human AMD, including thick diffuse sub-retinal pigment epithelium (RPE) deposits, lipid- rich drusen-like deposits, thickening of Bruch's membrane, patchy regions of RPE atrophy overlying photoreceptor degeneration and choroidal neovascularization (CNV). Importantly, these changes require the presence of all three risk factors. This animal model of spontaneously-occurring CNV is the first to incorporate physiologically-relevant risk factors of human disease. In this proposal, we aim to develop and establish this animal model of AMD, beyond its currently documented history, to document the reproducibility of the phenotype; to correlate changes in the RPE, Bruch's membrane and choroid to degenerative effects in the photoreceptors and to identify molecular pathways responsible for these changes. We expect that elucidation of the pathogenesis of the changes that occur in this model will contribute to our understanding of unknown molecular mechanisms leading to the neuropathology of AMD. To this end, we propose three Specific Aims: (1) Determine whether prolonged exposure to a HF-C diet increases severity of spontaneous CNV and sub-RPE deposit formation in a mouse model of AMD; (2) Examine and evaluate degenerative and synaptic changes in the retina in APOE mice with a focus on photoreceptors; (3) to identify genes in the RPE, choroid and retina that regulate pathways responsible for the development of deposits and CNV in the eyes of these apoE mice, using comparative microarray expression profiling. Analysis of these animals will provide insight into the pathogenesis of AMD as well as a means to separate the relative contribution and degenerative effects of specific risk factors.