Complement Factor H (Y402H) polymorphism for age-related macular degeneration alters retinal lipids

Age-related macular degeneration (AMD), the leading cause of blindness in the elderly, is associated with multiple risk factors and involves death of the retinal pigment epithelium (RPE). We investigated how the Y402H polymorphism of Complement Factor H (CFH) and cigarette smoke extract (CSE), major AMD genetic and environmental risks, affect lipid metabolism in RPE differentiated from induced pluripotent stem cells (iPSC-RPE) that were derived from human donors genotyped for low-risk (LR) or high-risk (HR) CFH. Results from discovery-based (lipidomics, proteomics) and targeted (mitochondrial fatty acid oxidation (FAO)) assays found significant genotype-dependent differences under basal conditions include higher free fatty acids and cholesterol esters in HR cells. CSE induced differences in proteins regulating lipid handling, lipolysis, and inflammation. Lower FAO in HR cells was observed in multiple donors and pairs of parent/isogenic edited lines compared with LR lines. CSE induced lipid accumulation, lipid composition remodeling, and upregulation of proteins involved in lipid synthesis/hydrolysis, production of bioactive lipid mediators, and metabolism of ceramide and cholesterol. These results elucidate putative mechanisms driving pathology in RPE harboring CFH Y402H.