Lim EW, Fallon RJ, Bates C, Ideguchi Y, Nagasaki T, Handzlik MK, Joulia E, Bonelli R, Green CR, Ansell BRE, Kitano M, Polis I, Roberts AJ, Furuya S, Allikmets R, Wallace M, Friedlander M, Metallo CM, and Gantner ML
Metabolic homeostasis is maintained by redundant pathways to ensure adequate nutrient supply during fasting and other stresses. These pathways are regulated locally in tissues and systemically via the liver, kidney, and circulation. Here, we characterize how serine, glycine, and one-carbon (SGOC) metabolism fluxes across the eye, liver, and kidney sustain retinal amino acid levels and function. Individuals with macular telangiectasia (MacTel), an age-related retinal disease with reduced circulating serine and glycine, carrying deleterious alleles in SGOC metabolic enzymes exhibit an exaggerated reduction in circulating serine. A Phgdh +/ - mouse model of this haploinsufficiency experiences accelerated retinal defects upon dietary serine/glycine restriction, highlighting how otherwise silent haploinsufficiencies can impact retinal health. We demonstrate that serine-associated retinopathy and peripheral neuropathy are reversible, as both are restored in mice upon serine supplementation. These data provide molecular insights into the genetic and metabolic drivers of neuro-retinal dysfunction while highlighting therapeutic opportunities to ameliorate this pathogenesis., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)