RT Journal Article SR Electronic T1 Identification of an anti-inflammatory protein from Faecalibacterium prausnitzii, a commensal bacterium deficient in Crohn’s disease JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 415 OP 425 DO 10.1136/gutjnl-2014-307649 VO 65 IS 3 A1 E Quévrain A1 M A Maubert A1 C Michon A1 F Chain A1 R Marquant A1 J Tailhades A1 S Miquel A1 L Carlier A1 L G Bermúdez-Humarán A1 B Pigneur A1 O Lequin A1 P Kharrat A1 G Thomas A1 D Rainteau A1 C Aubry A1 N Breyner A1 C Afonso A1 S Lavielle A1 J-P Grill A1 G Chassaing A1 J M Chatel A1 G Trugnan A1 R Xavier A1 P Langella A1 H Sokol A1 P Seksik YR 2016 UL http://gut.bmj.com/content/65/3/415.abstract AB Background Crohn’s disease (CD)-associated dysbiosis is characterised by a loss of Faecalibacterium prausnitzii, whose culture supernatant exerts an anti-inflammatory effect both in vitro and in vivo. However, the chemical nature of the anti-inflammatory compounds has not yet been determined.Methods Peptidomic analysis using mass spectrometry was applied to F. prausnitzii supernatant. Anti-inflammatory effects of identified peptides were tested in vitro directly on intestinal epithelial cell lines and on cell lines transfected with a plasmid construction coding for the candidate protein encompassing these peptides. In vivo, the cDNA of the candidate protein was delivered to the gut by recombinant lactic acid bacteria to prevent dinitrobenzene sulfonic acid (DNBS)-colitis in mice.Results The seven peptides, identified in the F. prausnitzii culture supernatants, derived from a single microbial anti-inflammatory molecule (MAM), a protein of 15 kDa, and comprising 53% of non-polar residues. This last feature prevented the direct characterisation of the putative anti-inflammatory activity of MAM-derived peptides. Transfection of MAM cDNA in epithelial cells led to a significant decrease in the activation of the nuclear factor (NF)-κB pathway with a dose-dependent effect. Finally, the use of a food-grade bacterium, Lactococcus lactis, delivering a plasmid encoding MAM was able to alleviate DNBS-induced colitis in mice.Conclusions A 15 kDa protein with anti-inflammatory properties is produced by F. prausnitzii, a commensal bacterium involved in CD pathogenesis. This protein is able to inhibit the NF-κB pathway in intestinal epithelial cells and to prevent colitis in an animal model.