Abstract
Presentation Description :
Age-related macular degeneration (AMD) is a multifactorial disease with age, environment, and genetics as contributing factors. Genetic analysis of AMD has identified 34 high-risk loci involved in different biological pathways, including complement, cell survival, lipid processing, extracellular matrix remodeling, and angiogenesis. The apparent defects in multiple pathways suggest that a single treatment for all AMD patients may not be effective and requires an understanding of the underlying cellular pathways causing AMD. This study defined protein changes in the retinal pigment epithelium (RPE) from human donors phenotyped for the presence and severity of AMD and genotyped for the single nucleotide polymorphisms (SNP) in complement factor H (CFH) that causes substitution of a tyrosine for histidine (Y402H). We used a proteomics approach to test the hypothesis that altered content of the RPE proteome will provide insight into the mechanism responsible for RPE cell death in late AMD. Proteins were isolated from human donor RPE harboring either the low-risk WT allele (n=123) or high-risk CFH SNP (n=120). The presence and severity of AMD was determined using the Minnesota Grading System, where MGS1 is donors without AMD and MGS2 to 4 are donors at progressively more severe disease. Proteins were analyzed by the UHR-IonStar pipeline featuring ultra-high-resolution MS1 acquisition and narrow-window MS1 feature extraction for quantification. A total of 6,996 proteins were quantified in all 243 samples. Statistical testing (2-way ANOVA) revealed significant effects of genotype (263 proteins), AMD status (807 proteins), and interaction of both genotype and AMD (420 proteins). Dunnett’s post-hoc statistics and bioinformatic analysis comparing each disease stage (MGS2-4) with MGS1 for each genotype revealed prominent discrepancies in AMD donors with and without the CFH high-risk SNP. Top altered pathways with high-risk CFH were changes in metabolism, including multiple mitochondrial proteins, stress response, lysosomes, and apoptosis. Top pathways in low-risk RPE included translation, exocytosis, transport of anions and gases, and extracellular matrix organization. These data provide novel insight into genotype-specific changes in the proteome, which will be valuable for designing patient-specific therapies to treat AMD.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.