Probiotic Propionibacterium freudenreichii requires SlpB protein to mitigate mucositis induced by chemotherapy

// Fillipe Luiz Rosa do Carmo 1 , 2 , Houem Rabah 2 , 3 , Barbara Fernandes Cordeiro 1 , Sara Heloisa da Silva 1 , Rafaela Miranda Pessoa 4 , Simone Odilia Antunes Fernandes 4 , Valbert Nascimento Cardoso 4 , Valerie Gagnaire 2 , Martine Deplanche 2 , Bruna Savassi 1 , Alessandra Figueiroa 1 , Emiliano Rosa Oliveira 1 , Caio Cesar Fonseca 1 , Maria Izabel Alves Queiroz 1 , Nubia Morais Rodrigues 1 , Savio Henrique de Cicco Sandes 1 , Alvaro Cantini Nunes 1 , Luisa Lemos 1 , Juliana de Lima Alves 1 , Ana Maria Caetano Faria 1 , Enio Ferreira 1 , Yves Le Loir 2 , Gwenael Jan 2 , * and Vasco Azevedo 1 , * 1 Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brasil 2 STLO, INRA, Agrocampus Ouest, UMR1253, Science & Technologie du Lait & de l'Oeuf, Rennes, France 3 Bba, Pole Agronomique Ouest, Regions Bretagne et Pays de la Loire, Rennes, France 4 Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brazil * These authors share senior authorship Correspondence to: Gwenael Jan, email: gwenael.jan@inra.fr Keywords: mucositis; probiotic; surface protein; immunomodulation; inflammation Received: June 11, 2019     Accepted: October 21, 2019     Published: December 31, 2019 ABSTRACT Propionibacterium freudenreichii CIRM-BIA 129 ( P. freudenreichii wild type, WT) is a probiotic bacterium, which exerts immunomodulatory effects. This strain possesses extractable surface proteins, including SlpB, which are involved in anti-inflammatory effect and in adhesion to epithelial cells. We decided to investigate the impact of slpB gene mutation on immunomodulation in vitro and in vivo . In an in vitro assay, P. freudenreichii WT reduced expression of IL-8 (p<0.0001) and TNF-α (p<0.0001) cytokines in LPS-stimulated HT-29 cells. P. freudenreichii Δ slpB , lacking the SlpB protein, failed to do so. Subsequently, both strains were investigated in vivo in a 5-FU-induced mucositis mice model. Mucositis is a common side effect of cytotoxic chemotherapy with 5-FU, characterized by mucosal injury, inflammation, diarrhea, and weight loss. The WT strain prevented weight loss, reduced inflammation and consequently histopathological scores. Furthermore, it regulated key markers, including Claudin-1 (cld1 , p<0.0005) and IL-17a ( Il17a , p<0.0001) genes, as well as IL-12 (p<0.0001) and IL-1β (p<0.0429) cytokines levels. Mutant strain displayed opposite regulatory effect on cld1 expression and on IL-12 levels. This work emphasizes the importance of SlpB in P. freudenreichii ability to reduce mucositis inflammation. It opens perspectives for the development of probiotic products to decrease side effects of chemotherapy using GRAS bacteria with immunomodulatory surface protein properties.