Researchers have discovered a new mode of vertical transmission of the microbiome from mother to child, where microbes in the maternal gut shared genes with microbes in the infant's gut during the perinatal period, starting immediately before birth and continuing for the first few weeks after birth. This horizontal gene transfer allowed maternal microbial strains to influence the functional capacity of the infant's microbiome, in the absence of persistent transmission of the microbial strains themselves.
Such a large-scale integrative analysis, presented December 22 in the journal Cell, provides a series of high-resolution snapshots of the dynamics of intestinal colonization that influence child development before and after birth.
“This is the first study to describe the transfer of mobile genetic elements between maternal and infant microbiomes,” says lead author Ramnik Xavier of the Broad Institute of MIT and Harvard. “Our study also integrated, for the first time, gut microbiome and metabolome profiles from mothers and infants and uncovered links between gut metabolites, bacteria, and breast milk substrates. This investigation represents a unique insight into the co-development of infant gut microbiomes and metabolomes under the influence of known maternal and dietary factors.”
Gut bacteria promote immune system maturation in part through the production of microbial metabolites. The development of the infant gut microbiome follows predictable patterns, beginning with the transmission of microbes from the mother to birth. In addition to immune system maturation, microbial metabolites also influence early cognitive development.
The perinatal period represents a critical window for cognitive and immune development, promoted by maternal and infant gut microbiota and their metabolites. However, the co-development of microbiomes and metabolomes during the perinatal period and the determinants of this process are not well understood.
To address this gap in knowledge, Xavier and colleagues tracked the co-development of microbiomes and metabolomes from late pregnancy to one year of age, using longitudinal multi-omics data from a cohort of 70 mother-child dyads. They found large-scale transfer of mobile genetic elements from mother to child, often involving genes associated with diet-related adaptations.
"The maternal microbiome could shape the child's gut microbiome through horizontal gene transfer, beyond the classical vertical transmission of strains and species. Furthermore, the identification of distinctive metabolomic profiles and microbe-metabolite interactions in the child's gut constitutes a platform for further study of microbial contributions to child development," says Xavier.
