Host Metabolic Regulation by the Gut Microbiota and Their Metabolites

Abstract

Interactions between the gut microbiome and humans have drawn significant attention in recent years and this relationship is now recognized as a critical factor in human pathophysiology. However traditional studies of the human gut microbiome have primarily focused on which bacterial species are associated with the host’s pathophysiology, while knowledge of how these bacteria exert their influence has been limited. Metabolites produced by gut bacteria are thought to serve as messengers that transmit signals from the bacteria. Here we introduce our recent study focusing on the relationship between the gut microbiome and host metabolism in an attempt to elucidate the functional aspects of the human gut microbiome. This study comprehensively searched for small molecules in feces in addition to performing metagenomic analysis. We identified an increase in carbohydrates, particularly monosaccharides, that are accessible to the host in the feces of insulin-resistant subjects. Although these compounds are not direct metabolites of gut bacteria our metagenomic findings suggest that changes in gut bacteria may contribute to an increase in intestinal monosaccharides through functional changes such as polysaccharide degradation and monosaccharide utilization. This study provides functional insights into how gut bacteria and their metabolites influence human metabolic functions opening the door to novel therapeutic interventions targeting gut bacterial metabolic functions and compounds produced by them.