Gut Bacterial Species Distinctively Impact Host Purine Metabolites during Aging in Drosophila.

Gut microbiota impacts the host metabolome and affects its health span. How bacterial species in the gut influence age-dependent metabolic alteration has not been elucidated. Here we show in Drosophila melanogaster that allantoin, an end product of purine metabolism, is increased during aging in a microbiota-dependent manner. Allantoin levels are low in young flies but are commonly elevated upon lifespan-shortening dietary manipulations such as high-purine, high-sugar, or high-yeast feeding. Removing Acetobacter persici in the Drosophila microbiome attenuated age-dependent allantoin increase. Mono-association with A. persici, but not with Lactobacillus plantarum, increased allantoin in aged flies. A. persici increased allantoin via activation of innate immune signaling IMD pathway in the renal tubules. On the other hand, analysis of bacteria-conditioned diets revealed that L. plantarum can decrease allantoin by reducing purines in the diet. These data together demonstrate species-specific regulations of host purine levels by the gut microbiome.