Selected Probiotic Lactobacilli Have the Capacity To Hydrolyze Gluten Peptides during Simulated Gastrointestinal Digestion

Abstract

The aim of this study was to demonstrate the capacity of probiotic lactobacilli to hydrolyze immunogenic gluten peptides. Eighteen commercial strains of probiotic lactobacilli with highly variable peptidase activity (i.e., aminopeptidase N, iminopeptidase, prolyl endopeptidyl peptidase, tripeptidase, prolidase, prolinase, and dipeptidase), including toward Pro-rich peptides, were tested in this study. Ten probiotic strains were selected on the basis of their specific enzyme activity. When pooled, these 10 strains provided the peptidase portfolio that is required to completely degrade the immunogenic gluten peptides involved in celiac disease (CD). The selected probiotic mixture was able to completely hydrolyze well-known immunogenic epitopes, including the gliadin 33-mer peptide, the peptide spanning residues 57 to 68 of the ␣9-gliadin (␣9-gliadin peptide 57-68), A-gliadin peptide 62-75, and ␥-gliadin peptide 62-75. During digestion under simulated gastrointestinal conditions, the pool of 10 selected probiotic lactobacilli strongly hydrolyzed the wheat bread gluten (ca. 18,000 ppm) to less than 10 ppm after 360 min of treatment. As determined by multidimensional chromatography (MDLC) coupled to nanoelectrospray ionization (nano-ESI)-tandem mass spectrometry (MS/MS), no known immunogenic peptides were detected in wheat bread that was digested in the presence of the probiotics. Accordingly, the level of cytokines (interleukin 2 [IL-2], IL-10, and interferon gamma [IFN-␥]) produced by duodenal biopsy specimens from CD patients who consumed wheat bread digested by probiotics was similar to the baseline value (negative control). Probiotics that specifically hydrolyze gluten polypeptides could also be used to hydrolyze immunogenic peptides that contaminate gluten-free products. This could provide a new and safe adjunctive therapy alternative to the gluten-free diet (GFD).IMPORTANCE This study confirmed that probiotic Lactobacillus strains have different enzymatic abilities for hydrolyzing polypeptides, including the Pro-rich epitopes involved in the pathology of CD. Ten lactobacilli with complementary peptidase activities that hydrolyze gluten peptides during simulated gastrointestinal digestion were selected and tested. The results collected showed the potential of probiotic formulas as novel dietary treatments for CD patients.KEYWORDS celiac disease, probiotic lactobacilli, peptidases, gluten immunogenic peptides, cytokines C eliac disease (CD) is an immune-mediated enteropathy that is triggered by the ingestion of gluten (in genetically susceptible individuals) and that results from the interaction between gluten and immune, genetic, and environmental factors (1). The prevalence of CD is as high as 1% in European countries (2), and its clinical

A Probiotic Preparation Hydrolyzes Gliadin and Protects Intestinal Cells from the Toxicity of Pro-Inflammatory Peptides

“…This could be reasonable, considering the presence of different kind of proteases in the intestinal tract, each according to its specificity, to proteolyze the proteins in smaller fragments. Our results are in line with previous publications which demonstrate that probiotic lactobacilli and bifidobacteria may digest gluten peptides, thus reducing their immunogenic potential [18,26,34]. Most notably, these properties may well justify the beneficial effects observed after administration of the same probiotic product studied in our paper to CD patients affected by IBS-like symptoms even if on a GFD [16], and reinforce the concept of the therapeutic potential of probiotics in CD.…”

“…Overall, five peptidases are required to completely degrade the 33-mer and other synthetic immunogenic peptides [25]. A recent study identified 10 strains of lactobacilli that, when pooled, provided the peptidase portfolio required to completely degrade the immunogenic gluten peptides, including the 33-mer, involved in CD [26]. A consortium of different strains was necessary to obtain this result because no single bacterial strain possesses all the peptidases required to completely hydrolyze gluten immunogenic epitopes [25,27,28].…”

Bacterial-Based Strategies to Hydrolyze Gluten Peptides and Protect Intestinal Mucosa

“…The levels of IL-2, IL-10, and IFN-g were overexpressed as a consequence of pepsin-trypsin (PT) wheat bread digestion products that were not treated with the probiotic strains. In contrast, the level of cytokines was similar to the baseline value in duodenal biopsy specimens exposed to PT digestion products from wheat bread, containing the selected probiotic strains (17).…”

Gluten Immunogenic Peptides as Standard for the Evaluation of Potential Harmful Prolamin Content in Food and Human Specimen

“…The challenge lies in preventing the degradation of the protease enzymes in the gastrointestinal tract [100]. A pool of selected lactobacilli demonstrated the capacity of strongly hydrolyzed the wheat bread gluten (18,000 ppm) to less than 10 ppm after 360 min of treatment by R5 sandwich and competitive ELISA [101]. The specificity of G12 moAb to detect GIP was exploited to evaluate the immunogenic potential of the pool of peptides produced during bacterial colonization [102].…”