Molecular Genetics of a Complement Factor H homolog

补体因子 H 同源物的分子遗传学

• 批准号: 10670958
• 负责人: BRUCE E VOGEL
• 金额: $ 38.63万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-30 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10670958
• 关键词: Adult; Affect; Afferent Neurons; Age; Age related macular degeneration; Alternative Complement Pathway; Autopsy; Binding; Binding Sites; Biological Assay; Blindness; Caenorhabditis elegans; Cell physiology; Cell surface; Cessation of life; Cilia; Complement Factor H; Data; Defect; Deposition; Disease; Dissection; Drusen; Enzymes; Epithelial Cells; Functional disorder; Genes; Genetic; Genetic Screening; Genetic Techniques; Genotype; Goals; Health Care Costs; Heparan Sulfate Proteoglycan; Heparitin Sulfate; Heparitin sulfotransferase; Homeostasis; Homologous Gene; Human; Individual; Inflammation; Lipids; Location; Maps; Membrane; Missense Mutation; Modeling; Molecular; Molecular Genetics; Mutation; Nephronophthisis; Neurons; Organoids; Pathogenesis; Pathogenicity; Patients; Phenotype; Photoreceptors; Proteoglycan; Retina; Risk Factors; Role; Structural defect; Structure; Structure of retinal pigment epithelium; Testing; Time; Tissues; United States; Universities; Variant; Work; complement pathway; design; follow-up; gene product; genome wide screen; induced pluripotent stem cell; inflammatory milieu; insight; loss of function mutation; mutant; next generation sequencing; novel; screening; sulfotransferase; syndecan

Project Summary Age-related macular degeneration (AMD) is the leading cause of vision loss in the developed world, affecting 11% of adults over the age of 85. In the United States alone, the disease currently afflicts 10 million individuals, with health care costs in the billions of dollars. The 2005 discovery of a Y402H variant in complement factor H (CFH) as a risk factor was a major advance in AMD genetics, however the functional significance of CFH and Y402H and the pathogenic mechanisms that initiate and promote the disease remain poorly understood. The canonical model of CFH function is that it binds to heparan sulfate (HS) on cell surfaces where it inhibits alternative complement pathway activity by two distinct mechanisms. Thus, the prevailing hypothesis for AMD pathogenesis is that missense mutations in HS binding sites in CFH, that include Y402H, result in defective binding to cell surfaces and ectopic activation of the alternate complement pathway in the retina. As a consequence of this activation, increased inflammation, cytolytic activity, and the accumulation of lipid-rich deposits (i.e. drusen) promote AMD pathogenesis. In stark contrast to this canonical model, preliminary studies by the PI and co-workers indicate that CFH-1, a CFH homolog in C. elegans, localizes on the ciliary membrane of C. elegans mechanosensory neurons in a heparan sulfate dependent manner where it maintains inversin/NPHP-2 within its eponymous cilia compartment. Additional data indicate that the inversin/NPHP-2 compartment is compromised in human Y402H photoreceptors, suggesting that this novel function for CFH-1 is conserved in human CFH. On the basis of this data, the PI proposes the radical hypothesis that CFH is an essential structural component of sensory neuron cilia in the human retina and that structural defects in photoreceptor cilia promote AMD pathogenesis in patients with CFH loss-of-function mutations. The aims of this proposal will extend these preliminary studies and use classic molecular and genetic techniques to dissect the mechanism of CFH-1 localization and function in restricting inversin/NPHP-2 distribution in C. elegans mechansensory neuron cilia. This novel model of CFH-1 function in C. elegans will be tested in human photoreceptors using a retina organoid model derived from induced pluripotent stem cells and genotyped post-mortem retina. Together, the proposed work will provide substantial insight into previously unappreciated CFH functions that are likely to contribute to a unique new model of AMD pathogenesis.

项目概要 年龄相关性黄斑变性（AMD）是发达国家视力丧失的主要原因 全世界 11% 的 85 岁以上成年人受到影响。仅在美国，该疾病目前就困扰着 1000 万人，医疗保健费用达数十亿美元。 2005年发现Y402H 然而，补体因子 H (CFH) 变异作为危险因素是 AMD 遗传学的重大进步 CFH 和 Y402H 的功能意义以及引发和促进的致病机制 人们对这种疾病仍然知之甚少。 CFH功能的典型模型是它与乙酰肝素结合 硫酸盐（HS）存在于细胞表面，通过两种不同的方式抑制替代补体途径活性 机制。因此，AMD 发病机制的普遍假设是 HS 错义突变 CFH 中的结合位点（包括 Y402H）会导致与细胞表面的结合缺陷和异位 视网膜中替代补体途径的激活。作为这种激活的结果， 炎症、细胞溶解活性增加以及富含脂质的沉积物（即玻璃疣）的积累 促进AMD发病机制。 与这个典型模型形成鲜明对比的是，PI 和同事的初步研究表明 CFH-1 是线虫中的 CFH 同源物，定位于线虫的睫状膜上 机械感觉神经元以硫酸乙酰肝素依赖性方式维持 inversin/NPHP-2 在其同名的纤毛室内。附加数据表明 inversin/NPHP-2 室 在人类 Y402H 光感受器中受到损害，表明 CFH-1 的这种新功能是 在人类CFH中保守。根据这些数据，PI 提出了一个激进的假设：CFH 是 人类视网膜感觉神经元纤毛的重要结构成分以及结构缺陷 光感受器纤毛中的蛋白促进 CFH 功能丧失突变患者的 AMD 发病机制。这 该提案的目标将扩展这些初步研究并使用经典的分子和遗传学 剖析CFH-1定位机制和限制inversin/NPHP-2功能的技术 线虫机械感觉神经元纤毛中的分布。 CFH-1 在秀丽隐杆线虫中发挥作用的新模型 将使用源自诱导多能的视网膜类器官模型在人类光感受器中进行测试 干细胞和基因分型的死后视网膜。总之，拟议的工作将提供大量 深入了解以前未被重视的 CFH 功能，这些功能可能有助于形成独特的新模型 AMD 发病机制。