Circadian rhythms and the early developing gut microbiome 2416

Abstract Description Circadian rhythms help balance energy budgets over a 24-hour period. Circadian rhythms also influence the immune system and the microbiota. Secretory IgA (sIgA) in the gut, for example, is primarily produced during the sleep cycle. Likewise, the gut microbiota responds to circadian rhythms with key phyla fluctuating throughout the day, heavily influenced by variables like sleep and diet. Here we investigated the role the circadian rhythm plays in early postnatal microbiome development. We used the laboratory opossum Monodelphis domestica as our model. As a marsupial, M. domestica are born in an extremely altricial and in an immunodeficient state, equivalent to a 40-day human embryo. They develop much of their adaptive immune system postnatally while also establishing their gut microbiome. Previously, we demonstrated that the newborn opossum gut microbiome resembles the mammary microbiome and, therefore, is most likely derived from milk. We demonstrate that adult marsupial gut microbiomes are influenced by a circadian rhythm, making this an ancient feature of mammals. We also investigate whether this rhythm is present in the opossum mammary, how it influences the developing neonatal gut microbiome, and correlation with the postnatal development of the immune system. Funding Sources Supported by NSF: IOS-2103367 Topic Categories Mucosal and Regional Immunology (MUC)