title: Identification of metabolic signatures linked to anti-inflammatory effects of Faecalibacterium prausnitzii.
abstract: Faecalibacterium prausnitzii is an anti-inflammatory commensal bacterium identified on the basis of human clinical data. The mechanisms underlying its beneficial effects are still unknown. Gnotobiotic mice harboring F. prausnitzii (A2-165) and Escherichia coli (K-12 JM105) were subjected to 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced acute colitis. The inflammatory colitis scores and a gas chromatography-time of flight (GC/TOF) mass spectrometry-based metabolomic profile were monitored in blood, ileum, cecum, colon, and feces in gnotobiotic mice. The potential anti-inflammatory metabolites were tested in vitro. We obtained stable E. coli and F. prausnitzii-diassociated mice in which E. coli primed the gastrointestinal tract (GIT), allowing a durable and stable establishment of F. prausnitzii. The disease activity index, histological scores, myeloperoxidase (MPO) activity, and serum cytokine levels were significantly lower in the presence of F. prausnitzii after TNBS challenge. The protective effect of F. prausnitzii against colitis was correlated to its implantation level and was linked to overrepresented metabolites along the GIT and in serum. Among 983 metabolites in GIT samples and serum, 279 were assigned to known chemical reactions. Some of them, belonging to the ammonia (α-ketoglutarate), osmoprotective (raffinose), and phenolic (including anti-inflammatory shikimic and salicylic acids) pathways, were associated with a protective effect of F. prausnitzii, and the functional link was established in vitro for salicylic acid. We show for the first time that F. prausnitzii is a highly active commensal bacterium involved in reduction of colitis through in vivo modulation of metabolites along the GIT and in the peripheral blood.
  
  
  OBJECTIVE
  Inflammatory bowel diseases (IBD) are characterized by low proportions of F. prausnitzii in the gut microbiome. This commensal bacterium exhibits anti-inflammatory effects through still unknown mechanisms. Stable monoassociated rodents are actually not a reproducible model to decipher F. prausnitzii protective effects. We propose a new gnotobiotic rodent model providing mechanistic clues. In this model, F. prausnitzii exhibits protective effects against an acute colitis and a protective metabolic profile is linked to its presence along the digestive tract. We identified a molecule, salicylic acid, directly involved in the protective effect of F. prausnitzii. Targeting its metabolic pathways could be an attractive therapeutic strategy in IBD.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Miquel
authors.forename: Marion
authors.initials: M
authors.lastname: Leclerc
authors.forename: Rebeca
authors.initials: R
authors.lastname: Martin
authors.forename: Florian
authors.initials: F
authors.lastname: Chain
authors.forename: Marion
authors.initials: M
authors.lastname: Lenoir
authors.forename: Sébastien
authors.initials: S
authors.lastname: Raguideau
authors.forename: Sylvie
authors.initials: S
authors.lastname: Hudault
authors.forename: Chantal
authors.initials: C
authors.lastname: Bridonneau
authors.affiliation: Life Sciences Division Lawrence, Berkeley National Lab, Berkeley, California, USA.
authors.forename: Trent
authors.initials: T
authors.lastname: Northen
authors.affiliation: Life Sciences Division Lawrence, Berkeley National Lab, Berkeley, California, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Bowen
authors.forename: Luis G
authors.initials: LG
authors.lastname: Bermúdez-Humarán
authors.forename: Harry
authors.initials: H
authors.lastname: Sokol
authors.forename: Muriel
authors.initials: M
authors.lastname: Thomas
authors.affiliation: philippe.langella@jouy.inra.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Langella
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000378:metabolism*; D001774:Blood Chemical Analysis; D003092:Colitis / Q000139:chemically induced / Q000473:pathology; D005243:Feces / Q000737:chemistry; D000068536:Bacillota / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000737:chemistry / Q000473:pathology; D008297:Male; D008807:Mice, Inbred BALB C; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000893:Anti-Inflammatory Agents