Fig. 1

Mechanisms of metabolic host-microbiome crosstalk. Host-microbiome interaction contributes to the organismic balance between energy intake and energy expenditure. For instance, the metabolic activities of the microbiome can produce diverse metabolites such as derivatives of tryptophan metabolism, short chain fatty acids (SCFAs), and other lipid metabolites that can interact with the immune or nervous systems of the colonized host to regulate energy intake and expenditure. SCFAs induce GLP-1 and PYY release from enteroendocrine cells. Epithelial Nfil3 regulates a lipid absorption program in a microbiome-regulated manner. Tryptophan metabolites influence immune cell activities