Small molecules, big effects: microbial metabolites in intestinal immunity

Abstract

The mammalian intestine is host to a vast number of microbial organisms. The immune system must balance tolerance with innate and adaptive defense mechanisms to maintain homeostasis with the microbial community. Interestingly, microbial metabolites have been shown to play a role in shaping the host immune response, thus assisting with adaptations that have significant implications for human health and disease. New investigations have uncovered roles for metabolites in modulating almost every aspect of the immune system. In this minireview, we survey these recent findings, which taken together reveal nuanced interactions that we are just beginning to understand.

Microbial community-scale metabolic modeling predicts personalized short chain fatty acid production profiles in the human gut

“…The human gut microbiota serves many functions: maintaining intestinal barrier function, regulating peripheral and systemic inflammation, and breaking down indigestible dietary components and host substrates into a wide range of bioactive compounds 1,2 . One of the primary mechanisms by which the gut microbiota impacts human health is through the production of small molecules that enter the circulation and are absorbed and transformed by host tissues [3][4][5] . Approximately half of the metabolites detected in human blood are significantly associated with cross-sectional variation in gut microbiome composition 6 .…”

Untargeted metabolomics of pulmonary tuberculosis patient serum reveals potential prognostic markers of both latent infection and outcome

“…Metabolites are small molecules that represent ongoing biological processes and may provide insights into the mechanisms that underlie the disease process as well as disease progression ( 8 ). Due to their special characteristics, metabolites have become potential disease biomarkers for disease ( 9 , 10 ).…”