Initiating Events in AMD: An Animal Model for the Human Disease

这项建议的广泛、长期目标是从分子角度界定 视网膜外层蛋白质的氧化修饰，免疫系统对它们的识别， 外层视网膜易受攻击，导致年龄相关性黄斑变性的疾病过程 退行性变（AMD）。在上一次资助期间完成的工作显示，AMD眼组织含有 通过加合长链多不饱和脂肪酸的氧化片段而修饰的高水平蛋白质 二十二碳六烯酸（DHA）。许多被这种加合物和其他加合物修饰的蛋白质被发现 玻璃疣和布鲁赫膜。此外，针对这些独特的羧乙基吡咯的自身抗体 加合物（CEP）在AMD患者的循环（血浆）中比在年龄匹配的 没有AMD的人从这些结果中，出现了以下关于 引发AMD的刺激：（a）.由于光感受器-RPE中的DHA浓度很高， 复杂的再加上DHA对氧化损伤的脆弱性，CEP加合物在 在外层视网膜中的时间，（B）。这些CEP加合物代表了免疫系统的新表位 导致产生抗CEP的自身抗体。（c）.抗CEP抗体反过来又参与 在Bruch膜-RPE界面处的补体攻击途径的激活响应于 在视网膜外层组织中继续产生CEP表位。为了验证这一假设， 正常小鼠与CEP加合的小鼠血清白蛋白。我们的预测是， CEP会使小鼠对在视网膜外膜中产生的内源性CEP加合蛋白敏感， 正常的衰老过程。反过来，免疫系统会通过攻击CEP存在的细胞来做出反应。 最容易产生表位。对这些小鼠的分析表明RPE中的局灶性病变， 这是一种类似地图状萎缩的光感受器，与干性AMD相关的致盲终期萎缩。 这种新的AMD小鼠模型将在正常小鼠中进一步表征，并且CEP免疫将 将其扩展到具有补体途径分子及其调节因子遗传缺陷的小鼠。一个新 小鼠AMD模型将是用于临床前试验的重要新资源， 设计用于预防或限制AMD进展的治疗剂。

The broad, long-term objective of this proposal is to define in molecular terms the linkage between the oxidative modifications of proteins in the outer retina, their recognition by the immune system and the vulnerability of the outer retina to attack, leading to the disease processes underlying age-related macular degeneration (AMD). Work completed during the last grant period revealed that AMD eye tissues contain high levels of proteins modified by the adduction of oxidation fragments of the long chain polyunsaturated fatty acid, docosahexaenoic acid (DHA). Many of the proteins modified by this and other adducts are found in drusen and Bruch's membrane. Furthermore, autoantibodies against these unique carboxyethylpyrrole adducts (CEP) are more abundant in the circulation (plasma) of individuals with AMD than are found in agematched individuals without AMD. From these results the following hypothesis has emerged regarding an initiating stimulus for AMD: (a). Because of the high concentration of DHA in the photoreceptors-RPE complex coupled with the vulnerability of DHA to oxidative damage, CEP-adducts are slowly generated over time in the outer retina, (b). These CEP-adducts represent new epitopes foreign to the immune system resulting in the generation of autoantibodies against CEP. (c). Anti-CEP-antibodies in turn are involved in activation of the complement attack pathway at the Bruch's membrane-RPE interface in response to the continued generation of CEP epitopes in tissues of the outer retina. To test this hypothesis we immunized normal mice with CEP-adducted mouse serum albumin. Our prediction was that systemic immunization with CEP would sensitize mice to endogenous CEP-adducted proteins generated in the outer retina during the normal course of aging. In turn the immune system would respond by attacking the cells where CEP epitopes are most readily generated. Analysis of these mice demonstrated focal lesions in the RPE and photoreceptors that mimic geographic atrophy, the blinding end-stage atrophy associated with dry AMD. This new mouse model for AMD will be further characterized in normal mice and the CEP-immunizations will be extended to mice with genetic defects in complement pathway molecules and their regulators. A new model for AMD in the mouse will be an important a new resource for use in the preclinical testing of therapeutics designed to prevent or limit the progression of AMD.