Odoribacter splanchnicus rescues aging-related intestinal P-glycoprotein damage via GDP-L-fucose secretion.

Intestinal P-glycoprotein (P-gp/ABCB1) is a key barrier limiting xenobiotic absorption, yet its functional decline with aging is poorly understood. Here, we show that gut microbiota dysbiosis contributes to age-associated P-gp deficiency. Integrated multi-omics analyses of human cohorts and murine models identify Odoribacter splanchnicus (O. splanchnicus) as a key commensal species whose depletion impairs intestinal P-gp function. Mechanistically, O. splanchnicus encodes GDP-mannose 4, 6-dehydratase (GMDS) and GDP-L-fucose synthase (TSTA3), enabling microbial biosynthesis of GDP-L-fucose. This metabolite directly promotes phosphorylation of the eukaryotic translation initiation factor 4E (eIF4E) and activates c-Jun-driven ABCB1 expression, thereby restoring xenobiotic efflux. These findings establish a microbiota-metabolite-transporter signaling axis that maintains intestinal detoxification, suggesting that targeting either microbes or metabolites could help prevent adverse drug reactions in older adults.