Gastro-intestinal microbes degrading dietary gluten

描述(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个胃肠道健康方面的作用正得到越来越广泛的认识。我们实验室最近的工作表明，居住在口腔--胃肠道的入口处--的细菌能够降解饮食面筋。在患有乳糜泻的患者中，谷蛋白会引起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，这种疾病是由面筋衍生的细胞毒肽触发的宿主抗自我反应。患有明显乳糜泻的患者患有胃肠道疾病，并有营养不良、贫血、骨质疏松症以及淋巴瘤和腺癌等胃肠道恶性肿瘤的风险。为了避免面筋毒性，患者被要求坚持严格的无面筋饮食，这是目前唯一可用的治疗选择。然而，饮食限制方法需要终生承诺，对患者来说是一个巨大的负担。口腔中天然面筋降解菌的发现为中和面筋的有害影响开辟了一条很有希望的新途径。目前的应用旨在探索驻留的胃肠道微生物的蛋白分解活性，并研究它们将面筋蛋白裂解成无毒多肽的潜力。其具体目标是：(1)鉴定牙菌斑和粪便标本中的面筋降解微生物(S)；(2)确定蛋白酶切割位点的特异性，评估免疫原性醇溶蛋白区域的取消，并测定pH活性谱；(3)在T细胞增殖实验和乳糜泻的体内模型中评估选定的微生物和纯化的酶制剂对醇溶蛋白的解毒作用；(4)鉴定、克隆和重组表达最有希望的酶(S)的基因(S)。通过胃肠道的自然定殖物减少面筋毒性将以益生菌的形式或应用纯面筋降解酶的形式提供新的治疗前景。 与公共健康相关：面筋是一种蛋白质，对面筋过敏的人和乳糜泻患者是不能容忍的。降低面筋毒性的一个有希望的方法是使用酶将这些蛋白质降解成无毒的片段。目前的应用寻求识别由人类胃肠道中的驻留微生物表达的面筋中和酶。

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.