Evans, I. A. | bioRxiv Science

bioRxiv2026

Metabolic Analysis of Human Retinal Pigment Epithelium and Choroid Tissue in Aging and Macular Degeneration

Age-related macular degeneration is a common ocular disease that causes vision loss in the elderly, with a complex set of risk factors and proposed mechanisms of pathogenesis. A powerful method for investigating changes in disease is metabolomics, by which small molecules can be identified and quantified simultaneously. We report here the metabolic analysis of human RPE-choroid tissue in aging and macular degeneration (AMD), as well as comparisons of human macular and extramacular RPE-choroid and neural retina. Levels of 215 metabolites were determined in young donors, AMD donors (early/intermediate, geographic atrophy, and neovascularization) and age-matched controls. The largest number of metabolite differences were observed between young and healthy aged controls, as opposed to between aged controls and any stage of AMD. Two notable metabolites found to be increased in aging choroids are trimethylamine N-oxide and uric acid, both of which were significant after Bonferroni correction. A mouse endothelial cell line treated with a high concentration of uric acid exhibited reduced migration in a wound closure assay. This study provides initial insights into the metabolome of human choroids in varying states of age and macular degeneration, as well as functional implications of these changes in the aging choroid.

cell biology↗

bioRxiv2025

PANK2-mediated de novo CoA synthesis is required for metabolic switching to fatty acid oxidation

Humans have 3 different PANK enzymes (PANK1-3) that catalyze the first step in the de novo synthesis of Coenzyme A (CoA). All PANKs are feedback inhibited by acyl-CoAs but only PANK2 can overcome this inhibition by binding palmitoyl-carnitine. Previous studies, conducted under glucose-replete conditions, have failed to detect a PANK2-mediated contribution to CoA synthesis. We found that exposure to BSA-conjugated palmitate (PAL-BSA) led to activation of fatty acid oxidation (FAO) and the accumulation of both palmitoyl-carnitine and palmitoyl-CoA in HEK293T cells, suggesting that PANK2 is active under these conditions. Isotope tracing experiments with 13C15N-pantothenate showed that PANK2 uniquely sustains de novo CoA synthesis and high production of Acetyl-CoA in the presence of long-chain fatty acids, indicating that FAO is limited by CoA availability in these conditions. Consistent with this mechanism, fibroblasts from PKAN patients exhibited impaired oxidation of palmitoyl-carnitine, confirming the functional relevance of our results in a disease context.

biochemistry↗