Succinate: a microbial product that modulates Drosophila nutritional physiology

Abstract

Gut microorganisms process food in animal guts and release many metabolic by-products, which are predicted to influence host physiological processes such as energy and lipid metabolism. Here, we investigate how succinate, a TCA cycle intermediate that is a major predicted release product of gut bacteria in Drosophila, influences the nutritional physiology of its Drosophila host. We administered succinate as a dietary supplement to microbe- free Drosophila, and quantified key nutritional indices. Dietary succinate significantly reduced fly lipid levels by up to ∼50%. This response was not replicated in parallel experiments conducted with dietary fumarate supplement, indicating that it could not be attributed to a general effect of TCA intermediates. We hypothesize that microbe-derived succinate may contribute to the reduced lipid content of Drosophila bearing gut bacteria, relative to axenic Drosophila. More generally, this study high- lights the importance of microbial-derived metabolites as regulators of host metabolism.