Gastro-intestinal microbes degrading dietary gluten

描述（由申请人提供）：胃肠道是多种微生物的主要储存库。定植微生物在促进宿主代谢过程和整体胃肠道健康方面的作用正得到越来越广泛的认识。我们实验室最近的研究表明，居住在胃肠道入口的口腔中的细菌能够降解饮食中的麸质。谷蛋白会引起乳糜泻患者的免疫反应和严重的临床症状。这种疾病的基础是一种自身免疫性疾病，其中宿主抗自我反应是由谷蛋白衍生的细胞毒性肽引发的。患有明显乳糜泻的患者患有胃肠病，并且有营养不良、贫血、骨质疏松和胃肠道恶性肿瘤（如淋巴瘤和腺癌）的风险。为了避免麸质毒性，患者必须坚持严格的无麸质饮食，这是目前唯一可用的治疗选择。然而，饮食限制方法需要终身承诺，对患者来说是一个重大负担。从口腔中发现的天然谷蛋白降解微生物为寻求中和谷蛋白的有害影响开辟了一条有希望的新途径。目前的应用旨在探索常驻胃肠道微生物的蛋白水解活性，并研究它们将麸质蛋白片段成无毒肽的潜力。具体目的是：(1)鉴定牙菌斑和粪便标本中的谷蛋白降解微生物；(2)确定蛋白酶裂解位点特异性，评估免疫原性麦胶蛋白区域的消除，并确定pH活性谱；(3)在t细胞增殖试验和乳糜泻体内模型中评估选定微生物和纯化酶制剂对麦胶蛋白的解毒作用；(4)鉴定、克隆和重组表达最有前途的酶基因。通过胃肠道的自然定植物减少谷蛋白毒性将以益生菌的形式或纯谷蛋白降解酶的应用提供新的治疗前景。

DESCRIPTION (provided by applicant): The gastrointestinal tract is a major reservoir of a wide variety of microorganisms. The role of the colonizing microorganisms in contributing to host metabolic processes and overall gastrointestinal health is becoming more widely recognized. Recent work in our laboratory has revealed that bacteria residing in the oral cavity, the entrance to the gastrointestinal tract, are able to degrade dietary gluten. Glutens elicit immunologic reactions and serious clinical conditions in patients suffering from celiac disease. The basis of this disease is an auto-immune disorder in which a host-anti-self response is triggered by gluten-derived cytotoxic peptides. Patients with overt celiac disease suffer from gastroenteropathy and are at risk for malnutrition, anemia, osteoporosis and gastrointestinal malignancies such as lymphoma and adenocarcinoma. To avoid gluten toxicity, patients are required to adherence to a strict gluten-free diet, which is currently the only treatment option available. However, the dietary restriction approach requires a life-long commitment and represents a significant burden to the patient. The discovery of natural gluten degrading microorganisms from the oral cavity opens a promising new avenue in the quest to neutralize the deleterious effects of glutens. The current application seeks to explore the proteolytic activities of resident gastrointestinal microorganisms and study their potential to fragment gluten proteins into non-toxic peptides. The specific aims are: (1) To identify gluten-degrading microorganism(s) in dental plaque and fecal specimens; (2) To define protease cleavage site specificity and assess the abolishment of immunogenic gliadin regions, and to determine pH activity profiles; (3) To assess gliadin detoxification by selected microbes and purified enzyme preparations in a T-cell proliferation assay and in an in vivo model for celiac disease; (4) To characterize, clone and recombinantly express the gene(s) of the most promising enzyme(s). Reduction of gluten toxicity by natural colonizers of the gastrointestinal tract would offer novel treatment perspectives in the form of probiotics or applications of pure gluten-degrading enzymes. PUBLIC HEALTH RELEVANCE: Glutens are proteins which are not tolerated by people who are allergic to gluten and by patients suffering from celiac disease. A promising approach to reduce gluten toxicity is using enzymes to degrade these proteins into non-toxic fragments. The current application seeks to identify gluten-neutralizing enzymes expressed by resident microbes from the human gastrointestinal tract.