A novel host-microbial interaction via the uptake of probiotic-derived molecules by intestinal epithelia

Backgrounds: Altered host-microbial interactions are involved in the pathogenesis of inflammatory bowel diseases (IBDs). This study proposes a novel host-microbial interaction mediated by probiotic-derived molecules.Methods:1. Conditioned media from Bacillus subtilis and Lactobacillus brevis SBL88 cultures were separated by various columns, and we examined the induction of Heat shock protein (Hsp) 27 in Caco2/bbe cells. Bioactive molecules were explored from a fraction that successfully induced Hsp 27. 2. An ex vivo mannitol flux test was used to assess the efficacies of the probiotic-derived molecules in improving intestinal barrier integrity. 3. We examined the molecules effect on the survival rate of dextran sodium sulfate (DSS)-induced colitis mice. 4. Fluorescence- or isotope-labeled bioactive molecules were used to determine the molecule uptake by Caco2/bbe cells. Results:Competence and sporulation factor (CSF) and polyphosphate derived from the Bacillus and Lactobacillus spp. were identified, respectively. These molecules improved the intestinal barrier impairment that had been induced by oxidant stress and also the survival rate of DSS-induced colitis mice. Labeled-CSF and polyphosphate were transported through the novel organic cation transporter 2 and integrin β1-mediated endocytosis, respectively.Conclusion:Probiotic-derived CSF and polyphosphate were taken up by intestinal epithelia in different manners, but both improved the intestinal barrier function and survival rate of mice with lethal colitis, thus suggesting that these molecules are potentially effective agents for treating IBD.