This study investigates the link between gut microbiota and depressive-like behaviors in mice using unpredictable chronic mild stress (UCMS). UCMS induced depressive behaviors, transferable via fecal microbiota transplantation (FMT) to naive recipients. This transfer was associated with decreased endocannabinoid (eCB) signaling due to lower fatty acid precursors. Enhancing central eCB signaling or *Lactobacilli* supplementation alleviated these effects, suggesting a mechanistic link between chronic stress, gut microbiota, and depressive behaviors mediated by the eCB system.

Grégoire Chevalier, Eleni Siopi, Laure Guenin-Macé, Maud Pascal, Thomas Laval, Aline Rifflet, Ivo Gomperts Boneca, Caroline Demangel, Benoit Colsch, Alain Pruvost, Emeline Chu-Van, Aurélie Messager, François Leulier, Gabriel Lepousez, Gérard Eberl, Pierre-Marie Lledo