Dietary Nanoparticles Interact with Gluten Peptides and Alter the Intestinal Homeostasis Increasing the Risk of Celiac Disease.
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ABSTRACT:
SUBMITTER: Mancuso C
PROVIDER: S-EPMC8201331 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Celiac sprue is a T-cell-mediated enteropathy elicited in genetically susceptible individuals by dietary gluten proteins. To initiate and propagate inflammation, proteolytically resistant gluten peptides must be translocated across the small intestinal epithelium and presented to DQ2-restricted T cells, but the effectors enabling this translocation under normal and inflammatory conditions are not well understood. We demonstrate that a fluorescently labeled antigenic 33-mer gluten peptide is translocated intact across a T84 cultured epithelial cell monolayer and that preincubation of the monolayer with media from gluten-stimulated, celiac patient-derived intestinal T cells enhances the apical-to-basolateral flux of this peptide in a dose-dependent, saturable manner. The permeability-enhancing activity of activated T-cell media is inhibited by blocking antibodies against either interferon-gamma or its receptor and is recapitulated using recombinant interferon-gamma. At saturating levels of interferon-gamma, activated T-cell media does not further increase transepithelial peptide flux, indicating the primacy of interferon-gamma as an effector of increased epithelial permeability during inflammation. Reducing the assay temperature to 4 degrees C reverses the effect of interferon-gamma but does not reduce basal peptide flux occurring in the absence of interferon-gamma, suggesting active transcellular transport of intact peptides is increased during inflammation. A panel of disease-relevant gluten peptides exhibited an inverse correlation between size and transepithelial flux but no apparent sequence constraints. Anti-interferon-gamma therapy may mitigate the vicious cycle of gluten-induced interferon-gamma secretion and interferon-gamma-mediated enhancement of gluten peptide flux but is unlikely to prevent translocation of gluten peptides in the absence of inflammatory conditions.
| S-EPMC2672868 | biostudies-other
Project description:Celiac disease (CeD) is an autoimmune disorder induced by consuming gluten proteins from wheat, barley, and rye. Glutens resist gastrointestinal proteolysis, resulting in peptides that elicit inflammation in patients with CeD. Despite well-established connections between glutens and CeD, chemically defined, bioavailable peptides produced from dietary proteins have never been identified from humans in an unbiased manner. This is largely attributable to technical challenges, impeding our knowledge of potentially diverse peptide species that encounter the immune system. Here, we develop a liquid chromatographic-mass spectrometric workflow for untargeted sequence analysis of the urinary peptidome. We detect over 600 distinct dietary peptides, of which ~35% have a CeD-relevant T cell epitope and ~5% are known to stimulate innate immune responses. Remarkably, gluten peptides from patients with CeD qualitatively and quantitatively differ from controls. Our results provide a new foundation for understanding gluten immunogenicity, improving CeD management, and characterizing the dietary and urinary peptidomes.
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Project description:Pathogens are exogenous agents capable of causing disease in susceptible organisms. In celiac sprue, a disease triggered by partially hydrolyzed gluten peptides in the small intestine, the offending immunotoxins cannot replicate, but otherwise have many hallmarks of classical pathogens. First, dietary gluten and its peptide metabolites are ubiquitous components of the modern diet, yet only a small, genetically susceptible fraction of the human population contracts celiac sprue. Second, immunotoxic gluten peptides have certain unusual structural features that allow them to survive the harsh proteolytic conditions of the gastrointestinal tract and thereby interact extensively with the mucosal lining of the small intestine. Third, they invade across epithelial barriers intact to access the underlying gut-associated lymphoid tissue. Fourth, they possess recognition sequences for selective modification by an endogenous enzyme, transglutaminase 2, allowing for in situ activation to a more immunotoxic form via host subversion. Fifth, they precipitate a T cell-mediated immune reaction comprising both innate and adaptive responses that causes chronic inflammation of the small intestine. Sixth, complete elimination of immunotoxic gluten peptides from the celiac diet results in remission, whereas reintroduction of gluten in the diet causes relapse. Therefore, in analogy with antibiotics, orally administered proteases that reduce the host's exposure to the immunotoxin by accelerating gluten peptide destruction have considerable therapeutic potential. Last but not least, notwithstanding the power of in vitro methods to reconstitute the essence of the immune response to gluten in a celiac patient, animal models for the disease, while elusive, are likely to yield fundamentally new systems-level insights.
| S-EPMC2323203 | biostudies-literature
Project description:Background and aimsThe dietary compliance and its assessment in celiac disease (CD) patients on a strict gluten-free diet (GFD) remain a challenge. Two relatively new, validated methods have been proposed to detect occasional gluten ingestion: standardized dietary questionnaire and determination of urinary gluten immunogenic peptides (GIPs). Our aim was to prospectively assess dietary compliance via these methods and compare their results with those of tissue transglutaminase antibodies (tTGA).MethodsThis was a prospective single-center study. Consecutive CD patients (aged 1-18 years) on a GFD scheduled for regular consultation between March and August 2019 were invited. In addition to standard care, a completed dietary questionnaire and urine sample for GIP were collected. Pearson's chi-square test, Fisher's exact test, and Mann-Whitney U test were performed.ResultsOf the 156 eligible children, 110 provided informed consent. Completed dietary questionnaire, GIP, and tTGA results were available from 86 children (median age 12.8 years, median GFD duration 30 months, 65% female). Adherence to the GFD evaluated by GIP, dietary questionnaire, and anti-tTGA was 94.2%, 75.6% and 94.2%, respectively. No association was found between the tTGA results and the detection of GIP, as well as between the tTGA results and the dietary questionnaires scores (P = .5 and .312, respectively). The participants perceived both the questionnaire and the measurement of GIP as reassuring with regard to correct implementation of the GFD.ConclusionAll the 3 methods have limitations to monitor dietary compliance. The comparison of their performance shows that the best single method is the use of the validated dietary questionnaire, which should therefore be implemented in the regular care for children with CD. The most effective combination of dietary questionnaire and urinary GIP determination should be used in specific clinical situations.
| S-EPMC11307387 | biostudies-literature
Project description:Gluten is a complex of proteins present in barley, wheat, rye and several varieties of oats that triggers celiac disease in genetically predisposed subjects. Gluten is notoriously difficult to digest by mammalian proteolytic enzymes and therefore, proline-rich digestion-resistant peptides contain multiple immunogenic epitopes. Prolyl endopeptidases (PEP) hydrolyse internal proline residues on the carboxyl side of peptides and have been proposed for food gluten detoxification and as oral enzyme supplementation for celiacs. The aim of this study was to identify new gluten-degrading microbial enzymes with the potential to reduce gluten immunogenicity by neutralizing its antigenic epitopes. Using a gluten-degrading colony screening approach, a bacterial isolate (2RA3) displaying the highest glutenase activity was selected, characterized and its genome completely sequenced. The identification through 16S rDNA gene sequencing showed a 99,1% similarity to Chryseobacterium taeanense. Hydrolysis of gluten immunogenic peptides (GIP) was further monitored, over a 48-hour period, by colony encapsulation in gliadin-containing microspheres, followed by detection with the G12 anti-GIP monoclonal antibody. Glutenase activity was detected in the extracellular medium of 2RA3 cultures, where gel electrophoresis and gliadin zymography revealed the presence of a ~50 kDa gluten-degrading enzyme. Nano-ESI-Q-TOF of the excised active band identified 7 peptides contained in the protein product predicted for an open reading frame (ORF) in the 2RA3 genome. Based on sequence similarity to the PEP family, the new enzyme was named PEP 2RA3. The PEP 2RA3 coding sequence was PCR-amplified from C. taeanense 2RA3, cloned and expressed in Escherichia coli as a C-terminally His-tagged recombinant protein and purified by Ni-NTA affinity chromatography. The recombinant protein, with predicted molecular mass and isoelectric point of 78.95 kDa and 6.8, respectively, shows PEP activity with standard chromogenic substrates, works optimally at pH 8.0 and 30°C and remains stable at pH 6.0 and 50°C, indicating a potential use in gluten-containing food process applications. The ability of the recombinant enzyme to degrade GIP in beer into smaller peptides was confirmed.
| S-EPMC6597064 | biostudies-literature
Project description:This study sought to identify proteins derived from dietary wheat, rye, and barley in human urine samples. The urinary peptidomes of celiac disease patients and healthy controls were compared.
2022-01-18 | PXD031048 | Pride
Project description:It is unclear whether patients with non-celiac gluten sensitivity (NCGS) can tolerate gluten. We have evaluated the changes of both gastrointestinal symptoms and quality of life for NCGS patients after the re-introduction of dietary gluten. Twenty-two NCGS patients reporting functional gastroenterological symptoms and on gluten-free diet (GFD) for the previous three weeks were exposed to incremental gluten-containing diets. Three groups were compared at baseline (immediately after 3-weeks on GFD) and immediately after the return of symptomatology: (i) a group tolerating a low-gluten diet (3.5 g gluten/day, week 1, n = 8), (ii) a group tolerating a mid-gluten diet (8 g gluten/day, week 2, n = 6), and (iii) a group tolerating a high-gluten diet (13 g gluten/day, week 3, n = 8). Their gastrointestinal symptoms and quality of life were assessed at baseline and post-intervention. The most common symptoms were: constipation (46%), abdominal pain (50%) and dyspepsia (38%). A decrease in several short form health survey (SF-36) sub-scores (all p < 0.03) after gluten re-introduction was only observed in the group tolerating the low-gluten diet; the same group showed a lower post-intervention role-emotional SF-36 score (p = 0.01). Most gastrointestinal symptoms remained similar after gluten re-introduction. However, a decrease in the general perception of well-being was only found after gluten re-introduction in the group tolerating a low-gluten diet (p = 0.01); the same was true when comparing the post-intervention general well-being perception among the three groups (p = 0.050). In conclusion, dissimilar responses from patients with NCGS were observed after the re-introduction of gluten, with gluten at a low dosage affecting the quality of life and general well-being of a group of patients, whereas others tolerate even higher doses of dietary gluten.
| S-EPMC6356445 | biostudies-literature
Project description:Dietary gluten proteins from wheat, rye, and barley are the primary triggers for the immuno-pathogenesis of Celiac Sprue, a widespread immune disease of the small intestine. Recent molecular and structural analyses of representative gluten proteins, most notably alpha- and gamma-gliadin proteins from wheat, have improved our understanding of these pathogenic mechanisms. In particular, based on the properties of a 33-mer peptide, generated from alpha-gliadin under physiological conditions, a link between digestive resistance and inflammatory character of gluten has been proposed. Here, we report three lines of investigation in support of this hypothesis. First, biochemical and immunological analysis of deletion mutants of alpha-2 gliadin confirmed that the DQ2 restricted T cell response to the alpha-2 gliadin are directed toward the epitopes clustered within the 33-mer. Second, proteolytic analysis of a representative gamma-gliadin led to the identification of another multivalent 26-mer peptide that was also resistant to further gastric, pancreatic and intestinal brush border degradation, and was a good substrate of human transglutaminase 2 (TG2). Analogous to the 33-mer, the synthetic 26-mer peptide displayed markedly enhanced T cell antigenicity compared to monovalent control peptides. Finally, in silico analysis of the gluten proteome led to the identification of at least 60 putative peptides that share the common characteristics of the 33-mer and the 26-mer peptides. Together, these results highlight the pivotal role of physiologically generated, proteolytically stable, TG2-reactive, multivalent peptides in the immune response to dietary gluten in Celiac Sprue patients. Prolyl endopeptidase treatment was shown to abolish the antigenicity of both the 33-mer and the 26-mer peptides, and was also predicted to have comparable effects on other proline-rich putatively immunotoxic peptides identified from other polypeptides within the gluten proteome.
| S-EPMC1343496 | biostudies-literature
Project description:OBJECTIVES:Treatment for celiac disease (CD) is a lifelong strict gluten-free diet (GFD). Patients should be followed-up with dietary interviews and serology as CD markers to ensure adherence to the diet. However, none of these methods offer an accurate measure of dietary compliance. Our aim was to evaluate the measurement of gluten immunogenic peptides (GIP) in stools as a marker of GFD adherence in CD patients and compare it with traditional methods of GFD monitoring. METHODS:We performed a prospective, nonrandomized, multicenter study including 188 CD patients on GFD and 84 healthy controls. Subjects were given a dietary questionnaire and fecal GIP quantified by enzyme-linked immunosorbent assay (ELISA). Serological anti-tissue transglutaminase (anti-tTG) IgA and anti-deamidated gliadin peptide (anti-DGP) IgA antibodies were measured simultaneously. RESULTS:Of the 188 celiac patients, 56 (29.8%) had detectable GIP levels in stools. There was significant association between age and GIP in stools that revealed increasing dietary transgressions with advancing age (39.2% in subjects ?13 years old) and with gender in certain age groups (60% in men ?13 years old). No association was found between fecal GIP and dietary questionnaire or anti-tTG antibodies. However, association was detected between GIP and anti-DGP antibodies, although 46 of the 53 GIP stool-positive patients were negative for anti-DGP. CONCLUSIONS:Detection of gluten peptides in stools reveals limitations of traditional methods for monitoring GFD in celiac patients. The GIP ELISA enables direct and quantitative assessment of gluten exposure early after ingestion and could aid in the diagnosis and clinical management of nonresponsive CD and refractory CD. Trial registration number NCT02711397.
| S-EPMC5059698 | biostudies-literature
Project description:Introduction and aimUsually, adherence to the gluten-free diet (GFD) in celiac patients is indirectly assessed through serological analysis, questionnaires, or invasive methods such as intestinal biopsy. The detection of gluten immunogenic peptides in urine (urinary gluten immunogenic peptides-uGIP) is a novel technique that directly evaluates the ingestion of gluten. The aim of this study was to evaluate the clinical efficacy of uGIP in the follow-up of celiac disease (CD).MethodsFrom April 2019 to February 2020, CD patients reporting complete adherence to the GFD were prospectively enrolled but were unaware of the reason for the tests. Urinary GIP, the celiac dietary adherence test (CDAT), symptomatic visual analog scales (VAS), and tissue transglutaminase antibodies (tTGA) titres were evaluated. Duodenal histology and capsule endoscopy (CE) were performed when indicated.ResultsA total of 280 patients were enrolled. Thirty-two (11.4%) had a positive uGIP test (uGIP+). uGIP+ patients did not show significant differences in demographic parameters, CDAT, or VAS scores. The tTGA+ titre was not related to the positivity of uGIP (14.4% vs. 10.9% in patients with tTGA+ and tTGA-). Regarding histology, 66.7% of the GIP+ patients had atrophy compared to 32.7% of the GIP patients (p-value 0.01). However, the presence of atrophy did not correlate with tTGA. Mucosal atrophy was detected in 29 (47.5%) out of 61 patients by CE. With this method, no noticeable dependence on uGIP results (24 GIP- vs. 5 GIP+) was observed.ConclusionsThe single uGIP test was positive in 11% of CD cases referring a correct GFD adherence. Furthermore, uGIP results significantly correlated with the duodenal biopsy, formerly considered the gold standard for assessing CD activity.
| S-EPMC10004805 | biostudies-literature