Editing AMD Risk Alleles in Human Cells

ABSTRACT Age-related macular degeneration (AMD) is a major cause of vision loss, affecting millions of individuals. Two major loci (ARMS2/HTRA1 and CFH) drive most of the risk for AMD. The genes responsible for the pathophysiology of these loci are expressed in ocular cells where they exert their effects. New developments in genome editing have greatly increased the efficiency of editing and reduced the likelihood of off-target events; and the application of these technologies (base editing and prime editing) offers promise for the permanent reduction of risk, especially important as a means to slow or arrest disease progression. Whereas existing treatments for exudative and atrophic AMD can be employed only following neovascularization or geographic atrophy, genome editing to diminish AMD risk in eyes with high-risk genotypes could be employed in a preventative manner. This grant application seeks to address the technological and tissue-specific considerations for editing the pathogenic alleles in two AMD loci (10q26 harboring ARMS2/HTRA1, and 1q harboring CFH). In this multicenter program with experts in retinal stem cell biology, AMD pathology, base editing and prime editing, virus like particle packaging, and gene expression, we will conduct base editing and prime editing of risk loci in human cells including iPSC-derived RPE, retina, and choroid, and donor retinal and choroidal explant cultures. Upon completion, this research program will address fundamental science questions regarding the impact of ARMS2 A69S gene on HTRA1 expression and the role of CFH variants in complement deposition. Additionally, it will shed light on translational science questions, exploring the efficacy of advanced gene editing for modifying critical risk genes in AMD.