Project description:Age-related macular degeneration (AMD) is a major cause of blindness in the western world. While genetic studies have linked both common and rare variants in genes involved in regulation of the complement system to increased risk of development of AMD, environmental factors, such as smoking and nutrition, can also significantly affect the risk of developing the disease and the rate of disease progression. Since epigenetics has been implicated in mediating, in part, the disease risk associated with some environmental factors, we investigated a possible epigenetic contribution to AMD. We performed genome-wide DNA methylation profiling of blood from AMD patients and controls. No differential methylation site reached genome-wide significance; however, when epigenetic changes in and around known GWASdefined AMD risk loci were explored, we found small but significant DNA methylation differences in the blood of neovascular AMD patients near age-related maculopathy susceptibility 2 (ARMS2), a top-ranked GWAS locus preferentially associated with neovascular AMD. The methylation level of one of the CpG sites significantly correlated with the genotype of the risk SNP rs10490924, suggesting a possible epigenetic mechanism of risk. Integrating genome-wide DNA methylation analysis of retina samples with and without AMD together with blood samples, we further identified a consistent, replicable change in DNA methylation in the promoter region of protease serine 50 (PRSS50). These methylation changes may identify sites in novel genes that are susceptible to non-genetic factors known to contribute to AMD development and progression.
Project description:Comparing fibroblasts and derived -iPSC and - RPE cells from human AMD and non-AMD donors Retinal pigment epithelium (RPE) generated from skin biopsies of donors with age-related macular degeneration (AMD) exhibit a disease phenotype and a distinct transcriptome compared to age-matched controls. We investigated whether similar differences existed in the skin fibroblasts and induced pluripotent stem cells (iPSCs) derived from them. Hierarchical cluster and principal component analyses revealed significant overlap in the transcriptome of fibroblasts of AMD and non-AMD donors. After reprogramming, iPSCs exhibited slight differences. In contrast, the transcriptome of RPE derived from AMD and normal donors segregated into two distinct clusters. Differences in the expression of specific genes that were evident between normal and AMD-derived RPE were not observed in fibroblasts or iPSCs. Mitochondrial respiration was reduced in RPE from AMD patients but not in fibroblast or iPSCs. RPE derived from AMD patients have a distinct transcriptome and phenotype compared to controls that is not observed in their corresponding skin fibroblasts or iPSCs.
Project description:Wet age-related macular degeneration (AMD), characterized by leaky neovessels emanating from the choroid, is a main cause of blindness. As current treatments for wet AMD require regular intravitreal injections of anti-VEGF biologics, there is a need for the novel development of less invasive treatments. Here, we developed a novel inhibitor of microtubule-associated End Binding 3 protein (EB3), herein termed EBIN, which blocked pathological Ca2+ signaling in activated endothelial cells and suppressed leakage of choroidal neovessels. Delivery of EBIN via eye drops in mouse and non-human primate (NHP) models of AMD prevented neovascular leakage and neovascularization as effectively as intravitreal injection of anti-VEGF therapy. EBIN activated Meis2-Pax6 regenerative pathways in metabolic-active endothelial cells comprising neovessels and promoted tissue regeneration. Furthermore, single nuclei assay for transposase-accessible chromatin sequencing (sn-ATAC-seq) analysis demonstrated that in metabolic-active endothelial cells, the RPE, and photoreceptors, EBIN induced global increases in chromatin accessibility, the biological process progressively inhibited in AMD patients. These results suggest the unique therapeutic mode of action of this novel drug candidate, which can potentially promote regeneration of eye tissue by reversing the degenerative processes underlying both the neovascular and atrophic forms of AMD.