Gestational administration of Bifidobacterium dentium results in intergenerational modulation of inflammatory, metabolic, and social behavior.

Prenatal stress (PNS) profoundly impacts maternal and offspring health, with enduring effects including microbiome alterations, neuroinflammation, and behavioral disturbances such as reductions in social behavior. Converging lines of evidence from preclinical and clinical studies suggest that PNS disrupts tryptophan (Trp) metabolic pathways and reduces gut Bifidobacteria, a known beneficial bacterial genus that metabolizes Trp. Specifically, previous work from our lab demonstrated that human prenatal mood disorders in mothers are associated with reduced Bifidobacterium dentium in infants at 13 months. Given that Bifidobacterium has been positively associated with neurodevelopmental and other health benefits and is depleted by PNS, we hypothesized that supplementing PNS-exposed pregnant dams with B. dentium would ameliorate PNS-induced health deficits. We measured inflammatory outputs, Trp metabolite levels and enzymatic gene expression in dams and fetal offspring, and social behavior in adult offspring. We determined that B. dentium reduced maternal systemic inflammation and fetal offspring neuroinflammation, while modulating tryptophan metabolism and increasing kynurenic acid and indole-3-propionic acid intergenerationally. Additional health benefits were demonstrated by the abrogation of PNS-induced reductions in litter weight. Finally, offspring of the B. dentium cohort demonstrated increased sociability in males primarily and increased social novelty primarily in females. Together these data illustrate that B. dentium can orchestrate interrelated host immune, metabolic and behavioral outcomes during and after gestation for both dam and offspring and may be a candidate for prevention of the negative sequelae of stress.