Gut Microbes and Potential Mechanism in inflammatory bowel disease (IBD)

 

Increase in IBD

Bacteria

-Adherent-invasive Escherichia coli

Induces inflammation, increases the permeability of the intestinal epithelium, disrupts epitelial mitochondrial networks, induces secretion of TNF

-Enterococcus faecium

Promotes cytokine expression and inflammation

-Enterotoxigenic Bacteroides fragilis

Produces BFT, which directly affects Wnt, NF-κB, STAT3, and MAPK pathways, activates the Stat3 transcription factor, increases Th17 and Treg cells, promotes mucosal permeability

-Ruminococcus gnavus

Produces complex glucorhamnan polysaccharide which can induce secretion of inflammatory cytokines by dendritic cells

-Enterobacteriaceae

Trigger strong inflammatory responses by expressing lipopolysaccharides

-Fusobacterium nucleatum

Activates epithelial TLR4, resulting in inflammation

 

Archaea

-Methanobrevibacter stadtmanae

Stimulates pro-inflammatory cytokine production by dendritic cells

 

Fungi

-Candida albicans

Enhances inflammation by increasing IL-17 and IL-23 production

-Malassezia

 Synthesizes indole compounds that act on AhR and regulates the production of inflammatory mediators

 

Virus

-Faecalibacterium prausnitzii temperate phages

Depletes F. prausnitzii

-Caudovirales

Decreases bacterial richness

 

Decrease in IBD

Bacteria

-F. prausnitzii

Produces butyrate, inhibits NF-κB pathway, maintains a balance of Th17/Treg cells, stimulates the production of anti-inflammatory cytokines, inhibits the production of inflammatory cytokines

-Nontoxigenic B. fragilis 

Induces anti-inflammatory effects of Treg, directs the development of CD4+T cells

-Roseburia (R. hominis,R. intestinalis)

Converts acetate to butyrate, has anti-inflammatory effect

-Clostridium

Produces butyrate which has anti-inflammatory effect

 

Archaea

-Methanobrevibacter smithii

Directs Bacteroides thetaiotaomicron-mediated fermentation of dietary fructans to acetate

 

Fungi

-Saccharomyces cerevisae

Prevents adherent-invasive E. coli from adhering to inflamed intestinal mucosa, prevents the transformation of C. albicans into invasive hyphal form

-Saccharomyces boulardii

Exhibits anti-inflammatory effects and protection against intestinal pathogens

Reference

DOI: 10.5217/ir.2023.00080