AUTHOR=Haileselassie Yeneneh , Navis Marit , Vu Nam , Qazi Khaleda Rahman , Rethi Bence , Sverremark-Ekström Eva 

TITLE=Postbiotic Modulation of Retinoic Acid Imprinted Mucosal-like Dendritic Cells by Probiotic Lactobacillus reuteri 17938 In Vitro

JOURNAL=Frontiers in Immunology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2016.00096

DOI=10.3389/fimmu.2016.00096

ISSN=1664-3224

ABSTRACT=<p>Lactobacilli are widely used as probiotics with beneficial effects on infection-associated diarrhea, but also used in clinical trials of e.g., necrotizing enterocolitis and inflammatory bowel diseases. The possibility of using probiotic metabolic products, so-called postbiotics, is desirable as it could prevent possible side effects of live bacteria in individuals with a disturbed gut epithelial barrier. Here, we studied how <italic>Lactobacillus reuteri</italic> DSM 17938 cell-free supernatant (<italic>L. reuteri</italic>-CFS) influenced retinoic acid (RA)-driven mucosal-like dendritic cells (DC) and their subsequent effect on T regulatory cells (Treg) <italic>in vitro</italic>. RA clearly imprinted a mucosal-like DC phenotype with higher IL10 production, increased CD103 and CD1d expression, and a downregulated mRNA expression of several inflammatory-associated genes (NFκB1, RELB, and TNF). Treatment with <italic>L. reuteri</italic>-CFS further influenced the tolerogenic phenotype of RA-DC by downregulating most genes involved in antigen uptake, antigen presentation, and signal transduction as well as several chemokine receptors, while upregulating IL10 production. <italic>L. reuteri</italic>-CFS also augmented CCR7 expression on RA-DC. In cocultures, RA-DC increased IL10 and FOXP3 expression in Treg, but pre-treatment with <italic>L. reuteri</italic>-CFS did not further influence the Treg phenotype. In conclusion, <italic>L. reuteri</italic>-CFS modulates the phenotype and function of mucosal-like DC, implicating its potential application as postbiotic.</p>