SOCIALGUT: UNRAVELING NEURAL CIRCUITS OF GUT MICROBIOTA INFLUENCE ON SOCIAL BEHAVIOUR

Several studies have revealed a link between the gut microbiota and social behavior, either through the identification of a specific population of bacteria or microbial metabolites correlated with social cognition. However, the mechanisms by which the gut-derived metabolites acting on the brain influences social behavior remain poorly understood. The ventral tegmental area (VTA), a key brain region regulating social behavior, has been shown to encode sociability, social novelty and social memory. Recent findings from Gabanyi et al., demonstrate that neurons in the VTA express Nod2, a pattern recognition receptor that recognizes bacterial cell wall fragments, like muropeptides.
We hypothesize that Nod2-expressing neurons in VTA contribute to the modulation of social behavior. Supporting this hypothesis, unpublished data demonstrated that muropeptide, muramyl dipeptide (MDP) was able to modulate neuronal activity in the VTA. Moreover, the selective depletion of Nod2 in VTA neurons affected social behavior in mice.
We are now characterizing the Nod2 positive-neurons in the VTA, to then characterize the neuronal circuitry of gut-brain communication underlying social behavior.
This project will establish a causal link between the gut microbiota and social behavior, and map the underlying neuronal mechanisms involved in social behavior.