Supplementation of Reduced Gluten Barley Diet with Oral Prolyl Endopeptidase Effectively Abrogates Enteropathy-Associated Changes in Gluten-Sensitive Macaques (original) (raw)
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Nutrients, 2015
Celiac disease (CD) affects approximately 1% of the general population while an estimated additional 6% suffers from a recently characterized, rapidly emerging, similar disease, referred to as non-celiac gluten sensitivity (NCGS). The only effective treatment of CD and NCGS requires removal of gluten sources from the diet. Since required adherence to a gluten-free diet (GFD) is difficult to accomplish, efforts to develop alternative treatments have been intensifying in recent years. In this study, the non-human primate model of CD/NCGS, e.g., gluten-sensitive rhesus macaque, was utilized with the objective to evaluate the treatment potential of reduced gluten cereals using a reduced gluten (RG; 1% of normal gluten) barley mutant as a model. Conventional and RG barleys were used for the formulation of experimental chows and fed to gluten-sensitive (GS) and control macaques to determine if RG barley causes a remission of dietary gluten-induced clinical and immune responses in GS macaques. The impacts of the RG barley diet were compared with the impacts of the conventional barley-containing chow and the GFD. Although remission of the anti-gliadin antibody (AGA) serum responses and an improvement of clinical diarrhea were noted after switching the conventional to the RG barley diet, production of
Transepithelial Transport and Enzymatic Detoxification of Gluten in Gluten-Sensitive Rhesus Macaques
PLoS ONE, 2008
Background and Aims: In a previous report, we characterized a condition of gluten sensitivity in juvenile rhesus macaques that is similar in many respects to the human condition of gluten sensitivity, celiac disease. This animal model of gluten sensitivity may therefore be useful toward studying both the pathogenesis and the treatment of celiac disease. Here, we perform two pilot experiments to demonstrate the potential utility of this model for studying intestinal permeability toward an immunotoxic gluten peptide and pharmacological detoxification of gluten in vivo by an oral enzyme drug candidate.
Next-generation therapies for celiac disease: The gluten-targeted approaches
Background: Wheat is one of the main foods of the human diet. It contains a protein complex, gluten, which is primarily responsible for the rheological behavior of wheat flours. However, it is gluten that triggers and maintains the enteropathy in celiac disease, a common autoimmune disorder of the small intestine. Individuals who suffer from celiac disease must follow a gluten-free diet, the only effective treatment available. Compliance to the restrictive diet is demanding and new treatment strategies for celiac disease are desired by patients and clinicians. Scope and approach: Based on increasing knowledge of the pathogenesis of celiac disease, some gluten-targeted approaches have been devised, such as down-regulation of gliadin expression, proteolysis of immunodominant peptides, transamidation of glutamine residues and sequestering of gliadin proteins. The present work critically discusses these experimental therapies, their usefulness, and the results obtained, in order to infer what the next generation of therapies for celiac disease will be. Key findings and conclusions: The gluten detoxification technologies have shown promising results in clinical trials by attenuating the symptomatology associated with celiac disease. These include gluten-specific proteases, which are close to entering the market for use by patients who may have mistakenly ingested food contaminated with gluten. Although so far none of the technologies allow the safe consumption of gluten without limitations, new and promising advances have been made, thus creating positive expectations in the search for an alternative to the gluten-free diet.
Nutrients, 2016
Theterm gluten intolerance may refer to three types of human disorders: autoimmune celiac disease (CD), allergy to wheat and non-celiac gluten sensitivity (NCGS). Gluten is a mixture of prolamin proteins present mostly in wheat, but also in barley, rye and oat. Gluten can be subdivided into three major groups: S-rich, S-poor and high molecular weight proteins. Prolamins within the groups possess similar structures and properties. All gluten proteins are evolutionarily connected and share the same ancestral origin. Gluten proteins are highly resistant to hydrolysis mediated by proteases of the human gastrointestinal tract. It results in emergence of pathogenic peptides, which cause CD and allergy in genetically predisposed people. There is a hierarchy of peptide toxicity and peptide recognition by T cells. Nowadays, there are several ways to detoxify gluten peptides: the most common is gluten-free diet (GFD), which has proved its effectiveness; prevention programs, enzymatic therapy, correction of gluten pathogenicity pathways and genetically modified grains with reduced immunotoxicity. A deep understanding of gluten intolerance underlying mechanisms and detailed knowledge of gluten properties may lead to the emergence of novel effective approaches for treatment of gluten-related disorders.
Emerging therapeutic options for celiac disease: potential alternatives to a gluten-free diet
Gastroenterology & hepatology, 2012
Celiac disease is an autoimmune disorder of the small intestine that is more common than was previously thought. This disease is caused by an inappropriate immune response to wheat gluten, barley, and rye. Three main pathways cause celiac disease: the environmental trigger (gluten), genetic susceptibility, and unusual gut permeability. The only treatment currently available is a strict gluten-free diet. Unfortunately, a majority of patients have difficulty complying with this diet, and the response to therapy is poor. Therefore, alternative treatments are being developed, and new insights into the pathophysiology of celiac disease have led to research into novel therapies. New treatments include engineering gluten-free grains, decreasing intestinal permeability by blockage of the epithelial zonulin receptor, inducing oral tolerance to gluten with a therapeutic vaccine, and degrading immunodominant gliadin peptides using probiotics with endopeptidases or transglutaminase inhibitors. ...
AJP: Gastrointestinal and Liver Physiology, 2006
Stepniak, Dariusz, Liesbeth Spaenij-Dekking, Cristina Mitea, Martine Moester, Arnoud de Ru, Renee Baak-Pablo, Peter van Veelen, Luppo Edens, and Frits Koning. Highly efficient gluten degradation with a newly identified prolyl endoprotease: implications for celiac disease. Celiac disease is a T cell-driven intolerance to wheat gluten. The gluten-derived T cell epitopes are proline-rich and thereby highly resistant to proteolytic degradation within the gastrointestinal tract. Oral supplementation with prolyl oligopeptidases has therefore been proposed as a potential therapeutic approach. The enzymes studied, however, have limitations as they are irreversibly inactivated by pepsin and acidic pH, both present in the stomach. As a consequence, these enzymes will fail to degrade gluten before it reaches the small intestine, the site where gluten induces inflammatory T cell responses that lead to celiac disease. We have now determined the usefulness of a newly identified prolyl endoprotease from Aspergillus niger for this purpose. Gluten and its peptic/ tryptic digest were treated with prolyl endoprotease, and the destruction of the T cell epitopes was tested using mass spectrometry, T cell proliferation assays, ELISA, reverse-phase HPLC, SDS-PAGE, and Western blotting. We observed that the A. niger prolyl endoprotease works optimally at 4 -5 pH, remains stable at 2 pH, and is completely resistant to digestion with pepsin. Moreover, the A. niger-derived enzyme efficiently degraded all tested T cell stimulatory peptides as well as intact gluten molecules. On average, the endoprotease from A. niger degraded gluten peptides 60 times faster than a prolyl oligopeptidase. Together these results indicate that the enzyme from A. niger efficiently degrades gluten proteins. Future studies are required to determine if the prolyl endoprotease can be used as an oral supplement to reduce gluten intake in patients.
Gut, 2007
Background: Coeliac disease is caused by an immune response to gluten. As gluten proteins are proline rich they are resistant to enzymatic digestion in the gastrointestinal tract, a property that probably contributes to the immunogenic nature of gluten. Aims: This study determined the efficiency of gluten degradation by a post-proline cutting enzyme, Aspergillus niger prolyl endoprotease (AN-PEP), in a dynamic system that closely mimics the human gastrointestinal tract (TIM system). Methods: Two experiments were performed. In the first, a slice of bread was processed in the TIM system with and without co-administration of AN-PEP. In the second, a standard fast food menu was used. Samples of the digesting meals were taken from the stomach, duodenum, jejunum and ileum compartments at time zero until 4 hours after the start of the experiment. In these samples the levels of immunogenic peptides from gliadins and glutenins were assessed by monoclonal antibody-based competition assays, Western blot analysis and proliferation T-cell assays. Results: AN-PEP accelerated the degradation of gluten in the stomach compartment to such an extent that hardly any gluten reached the duodenum compartment. Conclusion: AN-PEP is capable of accelerating the degradation of gluten in a gastrointestinal system that closely mimics in-vivo digestion. This implies that the coadministration of AN-PEP with a gluten-containing meal might eliminate gluten toxicity, thus offering patients the possibility of abandoning (occasionally) their strict glutenfree diet.
Evolving Therapy for Celiac Disease
Frontiers in Pediatrics
Gluten is known to be the main triggering factor for celiac disease (CeD), an immune-mediated disorder. CeD is therefore managed using a strict and lifelong gluten-free diet (GFD), the only effective treatment available currently. However, the GFD is restrictive. Hence, efforts are being made to explore alternative therapies. Based on their mechanisms of action on various molecular targets involved in the pathogenesis of CeD, these therapies may be classified into one of the following five broad approaches. The first approach focuses on decreasing the immunogenic content of gluten, using strategies like genetically modified wheat, intra-intestinal gluten digestion using glutenases, microwave thermal treatment of hydrated wheat kernels, and gluten pretreatment with either bacterial/ fungal derived endopeptidases or microbial transglutaminase. The second approach involves sequestering gluten in the gut lumen before it is digested into immunogenic peptides and absorbed, using binder drugs like polymer p(HEMA-co-SS), single chain fragment variable (scFv), and anti-gluten antibody AGY. The third approach aims to prevent uptake of digested gluten through intestinal epithelial tight junctions, using a zonulin antagonist. The fourth approach involves tissue transglutaminase (tTG) inhibitors to prevent the enhancement of immunogenicity of digested gluten by the intestinal tTG enzyme. The fifth approach seeks to prevent downstream immune activation after uptake of gluten immunogenic peptides through the intestinal mucosal epithelial layer. Examples include HLA-DQ2 blockers that prevent presentation of gluten derived-antigens by dendritic cells to T cells, immune-tolerizing therapies like the vaccine Nexvax2 and TIMP-Glia, cathepsin inhibitors, immunosuppressants like corticosteroids, azathioprine etc., and anti-cytokine agents targeting TNF-α and interleukin-15. Apart from these approaches, research is being done to evaluate the effectiveness of probiotics/prebiotics, helminth therapy using Necator americanus, low FODMAP diet, and pancreatic enzyme supplementation in CeD symptom control; however, the mechanisms by which they play a beneficial role in CeD are yet to be clearly established. Overall, although many therapies being explored are still in the pre-clinical phase, some like the zonulin antagonist, immune tolerizing therapies and glutenases have reached phase II/III clinical trials. While these potential options appear exciting, currently they may at best be used to supplement rather than supplant the GFD.
Targeted modification of wheat grain protein to reduce the content of celiac causing epitopes
Functional & Integrative Genomics, 2012
The prolamin peptides in wheat gluten and in the homologous storage proteins of barley and rye cause painful chronic erasure of microvilli of the small intestine epithelium in celiac patients. If untreated, it can lead to chronic diarrhea, abdominal distension, osteoporosis, weight-loss due to malabsorption of nutrients, and anemia. In addition to congenital cases, lifelong exposure to gluten proteins in bread and pasta can also induce development of celiac sprue in adults. To date, the only effective treatment is lifelong strict abstinence from the staple food grains. Complete exclusion of dietary gluten is, however, difficult due to use of wheat in many foods, incomplete labeling and social constraints. Thus, finding alternative therapies for this most common foodborne disease remained an active area of research, which has led to many suggestions in last few years. The pros and cons associated with these therapies were reviewed in the present communication. As different celiac patients are immunogenic to different members of the undigestible proline/glutamine rich peptides of ∼149 gliadins and low molecular weight glutenin subunits as well as the six high molecular weight glutenin subunits, an exhaustive digestion of the immunogenic peptides in the stomach, duodenum, jejunum, and ileum of celiacs is required. In view of the above, we evaluated the capacity of cereal grains to synthesize and store the enzymes prolyl endopeptidase from Flavobacterium meningosepticum and the barley cysteine endoprotease B2, which in combination are capable of detoxifying immunogenic gluten peptides in a novel treatment of celiac disease.
A Non-Human Primate Model for Gluten Sensitivity
PLoS ONE, 2008
Background and Aims: Gluten sensitivity is widespread among humans. For example, in celiac disease patients, an inflammatory response to dietary gluten leads to enteropathy, malabsorption, circulating antibodies against gluten and transglutaminase 2, and clinical symptoms such as diarrhea. There is a growing need in fundamental and translational research for animal models that exhibit aspects of human gluten sensitivity.