Abstract
Changes in sulfur-based redox metabolite profiles in multiple tissues of long-lived Snell dwarf mice were compared with age- and sex-matched controls. Plasma methionine and its oxidation products, hypotaurine and taurine, were increased in Snell dwarfs while cystine and glutathione levels were decreased, leading to an oxidative shift in the redox potential. Sexual dimorphism in renal cystathionine β-synthase (CBS) activity was observed in control mice but not in Snell dwarfs. Instead, female Snell mice exhibited ~2-fold higher CBS activity, comparable to levels seen in male Snell dwarf and in control mice. Taurine levels were significantly higher in kidney and brain of Snell dwarf versus control mice. Methionine adenosyltransferase (MAT) was higher in liver of Snell dwarfs, and the higher concentration of its product, S-adenosylmethionine, was correlated with elevated global DNA methylation status. Application of a mathematical model for methionine metabolism revealed that the metabolite perturbations in Snell dwarfs could be explained by decreased methionine transport, increased MAT and increased methyltransferase activity. Our study provides a comprehensive map of systemic differences in the sulfur network between Snell dwarfs and controls, providing the necessary foundation for assessment of nutrition-linked metabolic status in long-lived versus control animals.