Grant: Joint Canada-Israel Health Research Program

The human gastrointestinal tract is home to 100 trillion microorganisms and research has identified that this "gut microbiota" plays an important role in the development and normal function of our immune and nervous systems. Most recently evidence in animal models suggests that the gut microbiota can influence brain chemistry and consequently behavior. However, we do not know how this occurs. Critically, we also do not know how disruption of the normal gut microbiota early in life, due to antibiotic use for example, might influence brain development and potentially contribute to behavioral and/or mood disorders. In this study we will use mouse models to examine the effect of perinatal and early-life exposure to different antibiotics on brain chemistry and behavior in young adults. In particular we will focus on the potentially important contribution of the immune system to signaling between bacteria and the brain. Because relationships with associated bacteria are important for almost all animals, and likely rely on many evolutionarily conserved mechanisms, we will also take advantage of the much simpler system of gut microbiota -host interactions that occur in the fruit fly to identify potentially novel communication pathways between bacteria and the immune and nervous system. The successful completion of this project will give us with a greater understanding of the mechanisms underpinning the connection between gut bacteria and the brain and provide insight into the potential contribution of the gut microbiota disruption to the development of mood and behavioural disorders. Such knowledge may aid in the development of novel approaches to help maintain mental health.