Jonathan Swann is a Professor of Metabolism in the School of Human Development and Health at the University of Southampton and Visiting Professor in the Department of Metabolism, Digestion, and Reproduction at Imperial College London and the Department of Neuroscience at the Karolinska Institute. He leads a metabolomic-based research programme to understand the influence of gene-environment interactions on the mammalian metabolic system and their implications for development, health and disease. His primary interests involve developing analytical techniques and models to study the metabolic interactions between the gut microbiome and the mammalian host. He has a specific interest in the gut-brain axis and how nutritional exposures in early-life shape the colonization trajectories of the microbiota and their downstream consequences for behavior and cognitive function.
With a genetic entourage estimated to comprise over 3 million different genes, the gut microbiome contains approximately 100-150 times more genetic information than the human genome. Many of these microbial genes encode enzymes that substantially extend the metabolic repertoire of the collective supra-organism, increasing the diversity of substrates that can be processed and the compounds to which the host is exposed. Several of these molecules are bioactive and can be precursors for important host processes/metabolites and can also serve as ligands for receptors that modulate host gene expression. There is increasing evidence showing that metabolites modulated by these microorganisms can also participate in the bidirectional communication that exists between the gut microbiota and central nervous system, termed the microbiota-gut-brain axis. This includes neurotransmitters, short chain fatty acids, bile acids, choline metabolites, and various amino acid derivatives such as indoles, cresols, and imidazole propionate as well as molecules altered by immune interactions between the microbiota and host. Many of these microbial-derived signals translocate to the brain where they exert their effects while others act locally in the gut. Through various mechanisms these chemical messengers have been implicated in the modification of emotional behavior and cognitive function. Interestingly, their abundance can be modulated through dietary manipulation. This presentation will review our current understanding in this area.