Identification of proteins involved in the anti-inflammatory properties of Propionibacterium freudenreichii by means of a multi-strain study

Stéphanie-Marie Deutsch,Gwénaël Jan,Benoît Foligné,Mahendra Mariadassou,Valérie Briard-Bion,Julien Burati,Julien Jardin,Coline Plé,Caroline Le Maréchal,Sandrine Parayre,Rozenn Le Guellec,Victoria Chuat,Pierre Nicolas,Valentin Loux,Hélène Falentin,Vincent Peton

doi:10.1038/srep46409

Abstract

Propionibacterium freudenreichii, a dairy starter, can reach a population of almost 109 propionibacteria per gram in Swiss-type cheese at the time of consumption. Also consumed as a probiotic, it displays strain-dependent anti-inflammatory properties mediated by surface proteins that induce IL-10 in leukocytes. We selected 23 strains with varied anti-inflammatory potentials in order to identify the protein(s) involved. After comparative genomic analysis, 12 of these strains were further analysed by surface proteomics, eight of them being further submitted to transcriptomics. The omics data were then correlated to the anti-inflammatory potential evaluated by IL-10 induction. This comparative omics strategy highlighted candidate genes that were further subjected to gene-inactivation validation. This validation confirmed the contribution of surface proteins, including SlpB and SlpE, two proteins with SLH domains known to mediate non-covalent anchorage to the cell-wall. Interestingly, HsdM3, predicted as cytoplasmic and involved in DNA modification, was shown to contribute to anti-inflammatory activity. Finally, we demonstrated that a single protein cannot explain the anti-inflammatory properties of a strain. These properties therefore result from different combinations of surface and cytoplasmic proteins, depending on the strain. Our enhanced understanding of the molecular bases for immunomodulation will enable the relevant screening for bacterial resources with anti-inflammatory properties.

Highlights

To cite this version: Stéphanie-Marie Deutsch, Mahendra Mariadassou, Pierre Nicolas, Sandrine Parayre, Rozenn Le Guellec, et al
Propionibacterium freudenreichii (Pf) is a food grade bacterium with GRAS status that belongs to the dairy propionibacteria class
Twenty-three strains of Pf were tested for their immunomodulatory properties, based on different cytokine induction patterns following the stimulation of human peripheral blood mononuclear cell (PBMC), i.e. IL-10, IL-12, TNF-αand IFN-γ,and after growth in a dairy-based medium

Summary

Introduction

To cite this version: Stéphanie-Marie Deutsch, Mahendra Mariadassou, Pierre Nicolas, Sandrine Parayre, Rozenn Le Guellec, et al. Consumed as a probiotic, it displays strain-dependent anti-inflammatory properties mediated by surface proteins that induce IL-10 in leukocytes. The omics data were correlated to the anti-inflammatory potential evaluated by IL-10 induction This comparative omics strategy highlighted candidate genes that were further subjected to gene-inactivation validation. Propionibacterium freudenreichii (Pf) is a food grade bacterium with GRAS (generally recognized as safe) status that belongs to the dairy propionibacteria class It is most commonly used as a starter for the manufacture of fermented dairy products such Emmental and Leerdammer cheeses[1], but it is employed as a probiotic supplement[2]. The Pf species is characterised by high intraspecific variability among strains regarding numerous physiological traits, including their immunomodulation properties; the data on this latter trait have highlighted the remarkable anti-inflammatory properties of the species, their levels are strain-dependant[7]. In human PBMCs, nine strains of Pf were shown to induce the anti-inflammatory cytokine IL-10 with varying intensity, whereas no pro-inflammatory IL-12, www.nature.com/scientificreports/

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Conclusion