Loss of Kv8.2 in the Mouse Retina Is Associated With Altered One-Carbon Metabolism.

Photoreceptors are highly energy-demanding neurons, and disruption of photoreceptor signaling remodels retinal metabolism and contributes to degeneration, yet the pathways underlying these changes remain incompletely defined. Kv8.2 knockout (KO) mice, a model of KCNV2 retinopathy, exhibit impaired photoreceptor ion homeostasis and slow rod degeneration, providing an opportunity to investigate metabolic adaptation during progressive dysfunction. Untargeted metabolomic profiling was performed on retinas from wildtype (WT) and Kv8.2 KO mice at 1 and 13 months of age. Principal component analysis revealed distinct profiles for aged Kv8.2 KO retinas compared with aged WT and young groups, while young WT and KO retinas were metabolically similar. The major changes in aged Kv8.2 KO retinas compared to aged WT were reduced nucleobases and nucleosides while the amino acids homocysteine, methionine, and serine were elevated. These are signature metabolites in one-carbon metabolism, a metabolic hub influencing nucleotide metabolism, epigenic regulation, and anti-oxidant defense. Supervised modeling showed that these one-carbon-related changes emerge early and progress with age in Kv8.2 KO retinas. Together, these findings implicate altered one-carbon metabolism as a key mechanism in photoreceptor vulnerability and adaptation in slow retinal degeneration.