Complement factor H modulates lipoprotein clearance in AMD

补体因子 H 调节 AMD 中的脂蛋白清除

• 批准号: 10459378
• 负责人: CATHERINE BOWES RICKMAN
• 金额: $ 55.8万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10459378
• 关键词: Address; Affect; Age; Age related macular degeneration; Alternative Complement Pathway; American; Amino Acids; Animal Model; Apolipoprotein E; Apolipoproteins; Apolipoproteins B; Area; Binding; Biochemical; Biological Aging; Blindness; Blood; Bruch' s basal membrane structure; Cells; Cessation of life; Cholesterol; Choroid; Complement; Complement Activation; Complement Factor H; Complex; Data; Deposition; Developed Countries; Development; Diet; Disease; Drusen; Elderly; Epidemiology; Epithelial Cells; Eye; Eye diseases; Fatty acid glycerol esters; Functional disorder; Generations; Genes; Genetic Complementation Test; Genetic Polymorphism; Genetic Risk; Glycosaminoglycans; Goals; High Density Lipoproteins; Histidine; Human; Length; Link; Lipids; Lipoproteins; Liver; Metabolism; Modeling; Mus; National Eye Institute; National Institute on Aging; Outcome Study; Pathogenesis; Pathogenicity; Pathology; Pathway interactions; Patients; Peptides; Phenotype; Pigment Epithelium; Plasma; Play; Positioning Attribute; Proteins; Proteome; RNA Splicing; Research; Research Priority; Risk; Risk Factors; Role; Testing; Transgenic Mice; Tyrosine; Variant; age related; aged; apolipoprotein B-48; base; complement system; design; epidemiology study; extracellular; genetic analysis; genome wide association study; healthy aging; improved; in vivo; in vivo Model; induced pluripotent stem cell; lipid metabolism; mimetics; mouse model; novel; particle; prevent; public health relevance; reverse cholesterol transport; risk variant; socioeconomics; therapeutic target; trafficking

ABSTRACT In developed countries, age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the elderly and there are no treatments for the majority of patients. Early AMD is characterized by the formation of protein- and lipid-rich, sub-retinal pigmented epithelium (RPE) deposits. These deposits contain many constituents that are attributable to both the activation of the complement cascade and lipoprotein metabolism. In addition, complement and lipoprotein pathway genes have been independently associated with AMD in multiple ways including genetic risk association and epidemiological studies. Efforts to understand how lipid metabolism/trafficking and complement dysregulation contribute to AMD have been limited in part by the lack of age-dependent in vivo models that faithfully recapitulate these pathogenic aspects of the disease. The aim of the proposed studies is to leverage data derived using novel animal models of AMD that we have developed. These models invoke advanced age, complement dysregulation and lipid/cholesterol perturbation, all known contributors to human AMD risk. Specifically, we generated mouse models based on the most replicated genetic risk variant associated with AMD risk, the tyrosine (Y) to histidine (H) substitution at amino acid position 402 (Y402H) of human complement factor H, the soluble regulator of the alternative complement pathway. Only mice expressing the human H402 AMD risk variant (CFH-H/H) develop an AMD phenotype compared to mice expressing the normal human Y402 CFH variant. Significantly, the AMD phenotype correlates with changes in lipoprotein levels in blood, and in the RPE/Bruch’s membrane (BrM)/choroid complex. Thus, we are the first to observe a functional consequence of the Y402H polymorphism in vivo, which promotes an AMD-like pathology and affects lipoprotein levels in aged mice. In addition, we analyzed ApoA-1 containing lipoproteins isolated from BrM and plasma of elderly human donors and found they have very different protein compositions. The most striking difference is the significantly higher concentration of ApoB and ApoE in BrM, which are known to bind to glycosaminoglycans (GAGs) and could promote lipoprotein deposition onto BrM GAGs; likely initiating downstream effects that contribute to RPE dysfunction/death. Based on these observations and other studies we hypothesize that aberrant RPE-derived high-density lipoprotein (HDL)-like lipoprotein secretion contributes to AMD development, and is modulated by CFH. Thus, the goals of the proposed studies are to use our novel animal models of AMD and human induced pluripotent stem cell-derived RPE to (1) elucidate the mechanism by which CFH modulates lipoprotein clearance in AMD pathogenesis and (2) to test whether augmenting normal CFH and/or enhancing local HDL clearance are viable strategies for treating AMD. Outcomes from these studies will mechanistically determine the interaction of two risk factors, CFH and lipoproteins in AMD and establish proof of concept for these factors as therapeutic targets for AMD.

抽象的 在发达国家，与年龄相关的黄斑变性（AMD）是不可逆转的失明的主要原因 在过去，大多数患者都没有治疗。早期AMD的特征是 蛋白质和脂质富含视网膜下皮上皮（RPE）沉积物的形成。这些沉积物包含 许多构成归因于完成级联和脂蛋白的激活 代谢。另外，完成和脂蛋白途径基因与 AMD以多种方式包括遗传风险关联和流行病学研究。努力了解如何 脂质代谢/贩运和完成失调会导致AMD的贡献受到部分限制 缺乏体内模型的年龄依赖性，这些模型忠实地概括了该疾病的这些致病性方面。这 拟议的研究的目的是利用使用AMD的新型动物模型得出的数据 发达。这些模型调用了高龄，完成失调和脂质/胆固醇扰动， 人类AMD风险的所有已知贡献者。具体来说，我们基于最多的鼠标模型 与AMD风险相关的复制遗传风险变异，酪氨酸（Y）与氨基的组氨酸（H）取代 人类补体因子h的酸位置402（Y402H），替代性完成的固体调节剂 路径。仅表达人H402 AMD风险变体（CFH-H/H）的小鼠发展AMD表型 与表达正常人Y402 CFH变体的小鼠相比。值得注意的是，AMD表型 与血液中脂蛋白水平的变化以及RPE/BRUCH膜（BRM）/脉络膜相关 复杂的。这是我们第一个观察体内Y402H多态性的功能后果的人， 促进类似AMD的病理学，并影响老年小鼠的脂蛋白水平。此外，我们分析了apoa-1 含有从BRM分离的脂蛋白和老年人供体的血浆，发现它们非常 不同的蛋白质组成。最明显的差异是APOB的浓度明显更高 和BRM中的APOE，已知与糖胺聚糖（GAG）结合，可以促进脂蛋白 沉积到BRM插科打;可能会引发导致RPE功能障碍/死亡的下游效应。 基于这些观察结果和其他研究，我们假设异常RPE衍生的高密度 脂蛋白（HDL）样脂蛋白分泌有助于AMD发育，并由CFH调节。那， 拟议的研究的目标是使用我们的新型AMD和人类诱导多能动物模型 干细胞衍生的RPE至（1）阐明CFH调节AMD中脂蛋白清除率的机制 发病机理和（2）测试增加正常CFH和/或增强局部HDL清除率是否是 可行的治疗AMD策略。 这些研究的结果将从机械上确定两个危险因素的相互作用，CFH和 AMD中的脂蛋白并为这些因素建立概念证明，作为AMD的治疗靶标。