Impact of L rhamnosus on barrier integrity and microbiota. DNBS study

Increasing evidence supports the importance of gut barrier dysfunction in the onset of several diseases. In a previous study, we discovered that Lactobacillus rhamnosus CNCM I-3690 can protect intestinal barrier functions. Here, we investigated the bacterium’s mechanisms of action. Our results show that CNCM I-3690 can i) physically maintain gut barrier modulating goblet cells and the mucus layer and ii) counteract changes in local and systemic lymphocytes. Furthermore, colonic transcriptome analysis revealed that CNCM I 3690 enhances the expression of genes related to healthy gut permeability, motility, and absorption; cell proliferation; and protective functions. Finally, SpaFED pili are clearly important effectors since an L. rhamnosus DspaF mutant failed to provide the same benefits as the CNCM I 3690 wild type, upregulated proinflammatory pathways and modified the colon microbiota increasing Desulfobivrio genera . Taken together, our data suggest that CNCM I 3690 restores impaired intestinal barrier functions via anti-inflammatory and cytoprotective responses mediated by SpaFED pili.