Beneficial Propionibacteria within a Probiotic Emmental Cheese reduce Dextran Sodium Sulphate-Induced Colitis in Mice: a key role of SlpB.

BactInflam IJL focuses on the bacterial components involved in some inflammatory diseases. In particular, in two of them: chronic inflammatory bowel disease (IBD) and mastitis, affecting human health and animal health, respectively.

International audience

English. Introduction.Inflammatory Bowel Diseases (IBD), including Ulcerative Colitis (UC), coincide with alterations in the gut microbiota. Consumption of immunomodulatory strains of probiotic bacteria may induce or prolong remission in UC patients. Fermented foods, including cheeses, constitute major vectors for bacteria consumption. New evidences revealed anti-inflammatory effects in selected strains of Propionibacterium freudenreichii. Selected strains of the dairy starters Lactobacillus delbrueckii and Streptococcus thermophilus revealed similar immunomodulatory effects. We thus hypothesized that consumption of a functional cheese, fermented by such starter strains, may exert a positive effect on IBD. Methods.Results.We thus produced, in industrial conditions, an Emmental cheese using P. freudenreichii CIRM-BIA 129, in combination with L. delbrueckii CNRZ327 and S. thermophilus LMD-9, as starters. We investigated the impact of its consumption on gut inflammation, with respect to prevention of Dextran Sodium Sulphate (DSS)-induced colitis in mice.Consumption of this Emmental, reduced severity of subsequent DSS-induced colitis, weight loss, disease activity index and histological score. In a preventive way, it reduced small bowel Immunoglobulin A (IgA) secretion, restored occludin gene expression and prevented induction of Tumor Necrosis Factor α (TNFα), Interferon γ (IFNγ) and Interleukin-17 (IL-17). We then investigated the mechanism responsible for such a healing effect in P. freudenreichii. The slpB gene, encoding the surface layer protein SlpB, was inactivated. The resulting mutant failed to protect from inflammation, but rather exerted pro-inflammatory effects in mice.Conclusions.A combination of immunomodulatory strains of starter bacteria can be used to manufacture an anti-inflammatory cheese, as revealed in an animal model of colitis. Key surface proteins are involved in such immunomodulatory properties. This opens new perspectives for personalized nutrition in the context of IBD.