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

基本信息

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
项目类别：
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

项目摘要

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.

项目概要/摘要嗜酸性粒细胞性食管炎 (EoE) 是一种迅速出现的慢性疾病，主要由食物引发尽管名称为嗜酸粒细胞性食管炎，但其从炎症进展为纤维化。有证据表明，肥大细胞（MC）会导致哮喘和硬皮病等疾病的纤维化， MCs 通常会释放组胺和其他炎症介质，是 EoE 发病机制中不可或缺的一部分。免疫球蛋白 E (IgE) 交联，但多种证据表明 EoE 并不由 IgE 介导的 MC 也可以通过一系列阳离子物质（包括阿片类药物）被激活。新型 G 蛋白偶联受体，MAS 相关 G 蛋白偶联受体 X2 (MRGPRX2)。是 EoE 的两种最常见的触发因素，这些食物的消化会产生同源的 7 种氨基酸 (AA) 肽、β-酪啡肽 (BCM7) 和醇磷脂 (G7)，分别可以与 μ 阿片类药物结合我们的研究小组最近发现这两种肽也能激活大鼠腹膜 MC。使用 HEK293 MRGPRX2 转染的人类 LUVA MC 细胞系，我们的小组进一步发现：阿片样肽 BCM7 和 G7 仅在 MRGPRX2 存在的情况下才能激活这些细胞。这一发现引出了我们的中心假设：MC 是 EoE 发病机制中不可或缺的一部分，而非 IgE McGowan 博士建议通过食物诱导的 MRGPRX2 激活来介导 MC 的激活。通过检查 1) BCM7 和 G7 是否通过 MRGPRX2 激活 MC 来探索这一假设具有和不具有稳定转染的 MRGPRX2 的 HEK293 细胞和具有和不具有 siRNA 介导的 LUVA 细胞 MRGPRX2 的沉默；2) BCM7 和 G7 刺激 MC 是否会导致介质的产生已知会导致 EoE 中出现的纤维化和嗜酸性粒细胞募集；3) 是否与食管有关； EoE 患者的 MC 表达 MRGPRX2 并与纤维化特征相关。阐明BCM7和G7激活MCs导致炎症和纤维化的机制 EoE 中所见的现象将对我们理解 EoE 发病机制以及其他食物产生广泛的影响。相关病症，例如肠易激综合症和非乳糜泻麸质敏感性，也是由牛奶和小麦的摄入是一个具有重大公共卫生影响的问题，就像 BCM7 和 G7 一样。在美国和其他西方国家广泛消费，其中 EoE 的患病率证明这些食物来源的肽对 MC 的激活可能会导致范式转变。我们看待这种疾病的发病机制和治疗方案的方式。