Impacts on the Placenta-Brain Axis in Pregnant Mice Devoid of Gut Microbiota

Gut microbiota play an important role in regulating individual health. It is also increasingly apparent that changes in maternal gut microbiota result can render her offspring more susceptible to diseases later in life. Such bacterial induced changes likely originate in the womb. As the placenta is the primary communication organ between mother and conceptus, it is vulnerable to in utero environmental changes, including those associated with maternal gut microbiota. The placenta also relays nutritional and other factors, including serotonin, to the developing fetal brain that help guide development of this organ. Thus, placental disruptions can influence the placenta-brain axis and subsequently neurobehavioral programming with potential long-term consequences. One mechanism by which changes in maternal gut microbiota might effect the placenta are through alterations in bacterial short chained fatty acids (SCFA). The hypothesis, thus, tested in the current studies is that absence of a maternal gut microbiota, as occurs in germ-free (GF) mice, would impact bacterial SCFA in her fecal samples and in the fetal placenta and brain. Secondarily, we tested whether transcriptomic changes would be evident in the placenta and fetal brain from conceptuses derived from GF relative to multi-pathogen free (MPF) pregnant females.