IgE-Independent Mast Cell Activation by Food-Derived Peptides in Eosinophilic Esophagitis (EoE)

食物源性肽对嗜酸粒细胞性食管炎 (EoE) 中不依赖 IgE 的肥大细胞的激活

• 批准号: 10115609
• 负责人: Emily Clarke McGowan
• 金额: $ 20.19万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10115609
• 关键词: Address; Allergic Reaction; Amino Acids; Anaphylaxis; Asthma; Automobile Driving; Biopsy; CD34 gene; Cations; Cell Line; Cells; Chronic Disease; Chymase; Clinical; Consumption; Country; Data; Digestion; Disease; Enrollment; Eosinophilic Esophagitis; Eotaxin; Esophageal Tissue; Esophagus; Fibroblast Growth Factor; Fibrosis; Food; G-Protein-Coupled Receptors; Gluten; Histamine Release; Human; Hypersensitivity; IL3 Gene; IL5 gene; IgE; Immunofluorescence Microscopy; Inflammation; Inflammation Mediators; Inflammatory; Ingestion; Interleukin-13; Interleukin-4; Interleukin-5; Irritable Bowel Syndrome; Lead; Leukotrienes; Mediating; Mediator of activation protein; Messenger RNA; Milk; Monoclonal Antibodies; Muscle Contraction; Names; Opioid; Pathogenesis; Patients; Pattern; Peptides; Peripheral; Peritoneal; Phenotype; Platelet-Derived Growth Factor; Prevalence; Production; Prostaglandin D2; Public Health; Rattus; Resources; Role; Scleroderma; Small Interfering RNA; Smooth Muscle; Stimulus; Testing; Therapeutic Intervention; Tissues; Tryptase; United States; Wheat; base; beta-n-acetylhexosaminidase; cohort; crosslink; cytokine; eosinophil; extracellular; food antigen; mast cell; mu opioid receptors; novel; recruit; release of sequestered calcium ion into cytoplasm; stem cells

PROJECT SUMMARY/ABSTRACT Eosinophilic esophagitis (EoE) is a rapidly emerging chronic disease, predominantly triggered by food antigens, that progresses from inflammation to fibrosis. Despite the name eosinophilic esophagitis, increasing evidence suggests that mast cells (MC), which drive fibrosis in conditions such as asthma and scleroderma, are integral to the pathogenesis of EoE. MCs classically release histamine and other inflammatory mediators upon cross-linking of immunoglobulin E (IgE), but multiple lines of evidence have demonstrated that EoE is not mediated by IgE. MCs can also be activated by a range of cationic substances, including opiates, through a novel G-protein coupled receptor, MAS-related G protein-coupled receptor X2 (MRGPRX2). Milk and wheat are the two most common triggers of EoE, and digestion of these foods produces homologous 7 amino acid (AA) peptides, beta-casomorphin (BCM7) and gliadorphin (G7), respectively, that can engage µ opioid receptors and activate rat peritoneal MCs. Our group recently found that these two peptides also activate the human LUVA MC line. Using a HEK293 MRGPRX2 transfected cell line, our group further found that the opiate-like peptides BCM7 and G7 can activate these cells only in the presence of MRGPRX2. This finding leads to our central hypothesis that MCs are integral to the pathogenesis of EoE, and that non-IgE mediated activation of MCs occurs through food-induced activation of MRGPRX2. Dr. McGowan proposes to explore this hypothesis by examining 1) whether BCM7 and G7 activate MCs through MRGPRX2 using HEK293 cells with and without stably transfected MRGPRX2 and LUVA cells with and without siRNA-mediated silencing of MRGPRX2; 2) whether BCM7 and G7 stimulation of MCs leads to the production of mediators that are known to contribute to the fibrosis and eosinophil recruitment seen in EoE; and 3) whether esophageal MCs in patients with EoE express MRGPRX2 and correlate with fibrotic features. Elucidating the mechanism by which BCM7 and G7 activate MCs and lead to the inflammation and fibrosis seen in EoE will have broad implications for our understanding of EoE pathogenesis, as well as other food- related conditions such as irritable bowel syndrome and non-celiac gluten sensitivity that are also triggered by milk and wheat ingestion. This is a question with significant public health implications, as BCM7 and G7 are widely consumed in the United States and other westernized countries, where the prevalence of EoE is increasing. Demonstrating activation of MCs by these food-derived peptides could lead to a paradigm shift in the way that we view the pathogenesis and treatment options for this disease.

项目总结/摘要 嗜酸性食管炎（EoE）是一种快速出现的慢性疾病，主要由食物引起 抗原，从炎症发展到纤维化。尽管名称嗜酸性食管炎，增加 有证据表明，肥大细胞（MC），在哮喘和硬皮病等疾病中驱动纤维化， 是EoE发病机制的组成部分。MC典型地释放组胺和其他炎症介质 免疫球蛋白E（IgE）交联后，但多条证据表明，EoE不是 由IgE介导。MCs也可以被一系列阳离子物质激活，包括阿片类药物，通过一种类似的方式。 新的G蛋白偶联受体，MAS相关G蛋白偶联受体X2（MRGPRX 2）。牛奶和小麦 是EoE的两个最常见的触发因素，消化这些食物会产生同源的7种氨基酸 (AA)肽，β-酪啡肽（BCM 7）和gliadorphin（G7），分别可以参与μ阿片类药物 受体并激活大鼠腹膜MC。我们的研究小组最近发现，这两种肽也可以激活 人类LUVA MC系。使用HEK 293 MRGPRX 2转染细胞系，我们小组进一步发现 阿片样肽BCM 7和G7仅在MRGPRX 2存在时才能激活这些细胞。这 这一发现导致我们的中心假设，即MC是EoE发病机制的组成部分，非IgE MC介导的活化通过食物诱导的MRGPRX 2活化发生。麦高恩博士提议 通过检查1）是否BCM 7和G7通过MRGPRX 2激活MC来探索这一假设， 具有和不具有稳定转染的MRGPRX 2的HEK 293细胞和具有和不具有siRNA介导的MRGPRX 2的LUVA细胞 MRGPRX 2的沉默; 2）MCs的BCM 7和G7刺激是否导致介体的产生， 已知有助于在EoE中观察到的纤维化和嗜酸性粒细胞募集;以及3）是否食管 EoE患者的MC表达MRGPRX 2并与纤维化特征相关。 阐明BCM 7和G7激活MC并导致炎症和纤维化的机制 在EoE中看到的将对我们理解EoE发病机制以及其他食物产生广泛的影响， 相关的条件，如肠易激综合征和非腹腔麸质敏感性，也引发了 牛奶和小麦的摄入量这是一个具有重大公共卫生影响的问题，因为BCM 7和G7是 在美国和其他西方化国家广泛消费，在这些国家，EoE的患病率是 增加。证实这些食物来源的肽对MC的激活可能会导致MC的范式转变。 我们看待这种疾病的发病机制和治疗选择的方式。