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

AMD 的起始事件：人类疾病的动物模型

• 批准号: 7882922
• 负责人: JOE Gilbert HOLLYFIELD
• 金额: $ 32.36万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-02 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7882922
• 关键词: Age; Age related macular degeneration; Aging; Animal Model; Antibodies; Antigens; Appearance; Atrophic; Autoantibodies; Blood Circulation; Bruch' s basal membrane structure; Cells; Complement; Complement Activation; Complement Factor H; Complex; Coupled; Data; Development; Disease; Docosahexaenoic Acids; Drusen; Epitopes; Event; Eye; Generations; Genetic Polymorphism; Goals; Grant; Immune; Immune response; Immune system; Immunization; Individual; Inflammation; Inflammatory; Knockout Mice; Lesion; Light; Link; Modeling; Molecular; Mus; Mutation; Oxygen; Pathogenesis; Pathology; Pathway interactions; Patients; Photoreceptors; Plasma; Polyunsaturated Fatty Acids; Post-Translational Protein Processing; Preclinical Testing; Process; Property; Proteins; Publishing; Resources; Retina; Retinal; Rodent Model; Serum Albumin; Signal Transduction; Staging; Stimulus; Testing; Therapeutic; Time; Tissues; Wild Type Mouse; Work; adduct; base; cell type; complement pathway; design; genetic regulatory protein; geographic atrophy; human disease; innovation; insight; mouse model; normal aging; novel; oxidation; oxidative damage; prevent; response

DESCRIPTION (provided by applicant): 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 age-matched 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.

描述（由申请人提供）：该提案的广泛、长期目标是用分子术语定义外视网膜蛋白质的氧化修饰、免疫系统对它们的识别以及外视网膜受到攻击的脆弱性之间的联系，从而导致年龄相关性黄斑变性（AMD）的疾病过程。上一次资助期间完成的工作表明，AMD 眼组织含有高水平的蛋白质，这些蛋白质是通过长链多不饱和脂肪酸二十二碳六烯酸 (DHA) 的氧化片段加成而修饰的。许多由这种加合物和其他加合物修饰的蛋白质存在于玻璃疣和布鲁赫膜中。此外，AMD 患者循环（血浆）中针对这些独特的羧乙基吡咯加合物 (CEP) 的自身抗体比年龄匹配的非 AMD 患者中的抗体更为丰富。根据这些结果，出现了以下关于 AMD 的起始刺激的假设：(a)。由于光感受器-RPE 复合物中 DHA 浓度高，加上 DHA 容易受到氧化损伤，CEP 加合物会随着时间的推移在外视网膜中缓慢生成（b）。这些 CEP 加合物代表免疫系统外来的新表位，导致产生针对 CEP 的自身抗体。 （三）。抗CEP抗体反过来参与Bruch膜-RPE界面补体攻击途径的激活，以响应外视网膜组织中CEP表位的持续生成。为了检验这一假设，我们用 CEP 加合的小鼠血清白蛋白免疫正常小鼠。我们的预测是，CEP 全身免疫将使小鼠对正常衰老过程中视网膜外层产生的内源性 CEP 加合蛋白敏感。反过来，免疫系统会通过攻击最容易产生 CEP 表位的细胞来做出反应。对这些小鼠的分析表明，RPE 和光感受器出现局灶性病变，类似于地理萎缩，即与干性 AMD 相关的致盲终末期萎缩。这种新的 AMD 小鼠模型将在正常小鼠中进行进一步表征，并且 CEP 免疫将扩展到补体途径分子及其调节因子存在遗传缺陷的小鼠。小鼠 AMD 的新模型将成为用于预防或限制 AMD 进展的疗法临床前测试的重要新资源。