An integrative approach of [i]Propionibacterium freudenreichii[/i] immunomodulatory mechanisms

Propionibacterium freudenreichii is the main Propionibacterium consumed both in traditional cheeses and in innovative probiotic product. A portion of 10 grams of Emmental cheese provides around 10 10 live P. freudenreichii , a major bacterial intake in France and other industrialized countries. Surprisingly, little is known about its effect on human health, compared to lactobacilli or bifidobacteria. However, recent works indicate promising beneficial effects including modulation of intestinal microbiota, metabolic activities and inflammation. In this context, the molecular mechanisms responsible for the immunomodulatory properties of P.freudenreichii , and of fermented dairy product containing it, were investigated. In that aim, an integrative approach was undertaken, in a research program of the French National Agency for Research (ANR). It consisted of the sequencing and annotation of the genomes of 20 strains, followed by comparative genomics, in the design of a pangenomic chip, followed by comparative transcriptomic analysis , in a comparative surface proteomic analysis, and in comparison of the immunomodulatory properties, ex vivo and in vivo , using model cheeses. This investigation reveals, for the first time, the molecular mechanism responsible for modulation of the immune system and of inflammation by P.freudenreichii . These results are in accordance with clinical results obtained by others with the same bacterium