Protective Effects of Probiotic Mediated Digested Gliadin and 33-mer Peptide in Caco-2 Cell Cultures.

Gluten protein generates an immunogenic 33-mer peptide upon incomplete digestion, leading to induced cytotoxic and inflammatory responses in intestinal epithelial cells of susceptible individuals with Celiac disease (CeD). The present study investigates the protective effects of gluten hydrolyzing probiotic strains-Bacillus subtilis AJG10 and Bacillus tequilensis AJG23 on gliadin and 33-mer peptide in the Caco-2 cell model. The effect of probiotics on further degradation of 33-mer peptide and pepsin-trypsin digested gliadin was analysed using SDS-PAGE and mass spectrometry. The effect of all fractions on Caco-2 cell viability, nitric oxide (NO) production, and expression of pro-inflammatory cytokines was evaluated. A significant degradation of immunogenic peptide fragments after probiotic treatments resulted in 44%-53% reduction in NO production and a decrease of 27%-37% in cytokine expression and overall improvement in cell viability. The results suggested the potential of probiotic interventions in reducing the toxic effects of digested gliadin and immunogenic peptides.