Nitric oxide impacts human gut microbiota diversity and functionalities

• Main Authors: Bedu-Ferrari, C. (Author), Blanquet-Diot, S. (Author), Brazeau, L. (Author), Delmas, J. (Author), Denis, S. (Author), Etienne-Mesmin, L. (Author), Lebreuilly, L. (Author), Leclerc, M. (Author), Mariadassou, M. (Author), Mayeur, C. (Author), Ramarao, N. (Author), Rué, O. (Author), Tran, S.-L (Author)
• Format: Article
• Language: English
• Published: American Society for Microbiology 2021
• Subjects: amino acid; Anaerobic digester; Article; Bacteroidaceae; biomass; chemoluminescence; Clostridium leptum; controlled study; Desulfovibrio vulgaris; Diversity; Enterobacteriaceae; Enterococcus faecalis; Escherichia coli; Faecalibacterium prausnitzii; feces microflora; fermentation; Functional analysis; homeostasis; human; human experiment; in vitro study; intestine flora; metabolome; Metabolomics; microbial diversity; microbiome; Microbiota; nitric oxide; Nitric oxide; nitrogen metabolism; nonhuman; normal human; oxidation reduction potential; Proteus mirabilis; RNA 16S; Ruminococcaceae; Single strain; Veillonellaceae
• Online Access: View Fulltext in Publisher

 The disruption of gut microbiota homeostasis has been associated with numerous diseases and with a disproportionate inflammatory response, including overproduction of nitric oxide (NO) in the intestinal lumen. However, the influence of NO on the human gut microbiota has not been well characterized yet. We used in vitro fermentation systems inoculated with human fecal samples to monitor the effect of repetitive NO pulses on the gut microbiota. NO exposure increased the redox potential and modified the fermentation profile and gas production. The overall metabolome was modified, reflecting less strict anaerobic conditions and shifts in amino acid and nitrogen metabolism. NO exposure led to a microbial shift in diversity with a decrease in Clostridium leptum group and Faecalibacterium prausnitzii biomass and an increased abundance of the Dialister genus. Escherichia coli, Enterococcus faecalis, and Proteus mirabilis operational taxonomic unit abundance increased, and strains from those species isolated after NO stress showed resistance to high NO concentrations. As a whole, NO quickly changed microbial fermentations, functions, and composition in a pulse- and dose-dependent manner. NO could shift, over time, the trophic chain to conditions that are unfavorable for strict anaerobic microbial processes, implying that a prolonged or uncontrolled inflammation has detrimental and irreversible consequences on the human microbiome. © 2021 Leclerc et al.