Colonocyte-derived lactate promotes E. coli fitness in the context of inflammation-associated gut microbiota dysbiosis

Background: Intestinal inflammation disrupts the microbiota composition leading to an expansion of Enterobacteriaceae family members (dysbiosis). Associated with this shift in microbiota composition is a profound change in the metabolic landscape of the intestine. It is unclear how changes in metabolite availability during gut inflammation impact microbial and host physiology. Results: We investigated microbial and host lactate metabolism in murine models of infectious and non-infectious colitis. During inflammation-associated dysbiosis, lactate levels in the gut lumen increased. The disease-associated spike in lactate availability was significantly reduced in mice lacking the lactate dehydrogenase A subunit in intestinal epithelial cells. Commensal E. coli and pathogenic Salmonella, representative Enterobacteriaceae family members, utilized lactate via the respiratory L-lactate dehydrogenase LIdD to increase fitness. Furthermore, mice lacking the lactate dehydrogenase A subunit in intestinal epithelial cells exhibited lower levels of inflammation in a model of noninfectious colitis. Conclusions: The release of lactate by intestinal epithelial cells during gut inflammation impacts the metabolism of gut-associated microbial communities. These findings suggest that during intestinal inflammation and dysbiosis, changes in metabolite availability can perpetuate colitis-associated disturbances of microbiota composition.

Automated summary

This study investigated the metabolism of lactate in the gut during intestinal inflammation and its impact on microbial and host physiology. The researchers found that lactate levels in the gut lumen increased during inflammation-associated dysbiosis. Mice lacking the lactate dehydrogenase A subunit in intestinal epithelial cells showed reduced lactate availability, while commensal E. coli and pathogenic Salmonella utilized lactate to increase fitness. Additionally, these mice exhibited lower levels of inflammation in a model of noninfectious colitis. The release of lactate by intestinal epithelial cells during gut inflammation affects the metabolism of gut-associated microbial communities, perpetuating disturbances in microbiota composition.