Molecular and cellular mechanisms in food anaphylaxis

食物过敏反应的分子和细胞机制

基本信息

批准号：
10408011
负责人：
RAIF SALIM GEHA
金额：
$ 54.8万
依托单位：
BOSTON CHILDREN'S HOSPITAL
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：
2020-06-01 至 2025-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10408011
关键词：
Adult Affect Allergic Anaphylaxis Antibiotics Antibodies Antigens Automobile Driving Cell physiology Cells Child Disease model Eczema Enteral Exhibits Food Food Hypersensitivity General Population Genes Germ-Free Guanine Nucleotide Exchange Factors IgE Immune Immunity Incidence Ingestion Interleukin-17 Interleukin-4 Intestinal permeability Intestines Lamina Propria Mediating Molecular Mouse Strains Mus Oral Outcome Patients Phenocopy Predisposition Prevention strategy Production Regulatory T-Lymphocyte Role STAT3 gene Sampling Serum Severities Signal Transduction Small Intestines T-Lymphocyte Testing Th2 Cells Transgenic Mice Tryptase absorption antigen challenge antimicrobial peptide crosslink cytokine dysbiosis fecal transplantation food allergen gut microbiome interleukin-22 intestinal epithelium mast cell microbiome novel novel strategies passive sensitization recurrent infection

项目摘要

Abstract Food allergy is mediated by antigen crosslinking of IgE antibodies bound to mast cells (MC) and is often associated with intestinal dysbiosis. IgE sensitization to food is not by itself sufficient to drive food anaphylaxis. Intestinal MC load, which controls intestinal permeability and systemic antigen absorption, is an important determinant. The guanine nucleotide exchange factor, DOCK8, is important for STAT3 activation, IL-22, and IL- 17 production. As food allergy and anaphylaxis are cardinal features of DOCK8 deficient patients, DOCK8 deficiency offers an attractive disease model for identifying mechanisms underlying food allergy. We find elevated serum tryptase levels in DOCK8 deficient patients. Dock8-/- mice exhibit exaggerated IgE- mediated anaphylaxis to oral, but not i.p. antigen challenge, as well as intestinal MC expansion, which we show is neither a consequence of a cell intrinsic DOCK8 deficiency within MCs, nor dependent on IgE. Mice with selective deficiency in DOCK8 in T cells phenocopy Dock8-/- mice, and both exhibit similar intestinal dysbiosis T cells in the small intestine (SI) lamina propria (LP) of Dock8-/- mice have decreased expression of Il22 and Il17 and increased expression of Il4 and Il13. DOCK8 deficient SI epithelium has decreased expression of antimicrobial peptide (AMP) genes, but increased numbers of tuft cells and elevated Il25 expression. Treatment with either sIL-22 or an oral antibiotic cocktail normalizes intestinal MC expansion, suggesting a critical role for dysbiosis driven by type 17 cytokine deficiency. IL-25 and IL-4 blockade reduce intestinal MC load and passive oral anaphylaxis in Dock8-/- mice, suggesting a critical role for IL-25, which promotes type 2 cytokine production by ILC2s and Th2 cells, and for IL-4, which acts on MCs. Importantly, germ free (GF) WT recipients of fecal microbiota transplantation (FMT) from conventionally raised Dock8-/- mice have significantly greater intestinal MC load compared to GF WT recipients of FMT from conventionally raised WT controls. Thus, our proposed studies investigate the mechanisms by which dysbiosis in DOCK8 deficiency may increase intestinal MC load and thereby promote anaphylaxis are relevant to patients with classic food allergy. We will test the hypotheses that 1) reduced production of type 17 cytokines due to defective STAT3 activation in DOCK8 deficiency results in intestinal dysbiosis, 2) dysbiosis causes intestinal tuft cells to produce IL-25, which drives type 2 cytokine production by ILC2s and Th2 cells, and 3) IL-4, in turn, drives intestinal MC expansion and activation, thereby promoting anaphylaxis to ingested antigen. We will make use of transgenic mice and take advantage of our access to DOCK8 deficient patients and previously well-characterized fecal samples from children with classic food allergy to test our hypotheses. The proposed studies will delineate how immune mechanisms important for maintaining the intestinal microbiome regulate intestinal MC expansion and activation, and thereby the severity of food allergy, thus identifying novel strategies for the prevention and treatment of food allergy.

抽象的食物过敏是由与肥大细胞（MC）结合的IgE抗体的抗原交联介导的，并且通常是与肠道营养不良有关。 IgE对食物的敏感本身不足以驱动食物过敏反应。控制肠道通透性和全身性抗原吸收的肠道MC负载是重要的决定因素。鸟嘌呤核苷酸交换因子DOCK8对于STAT3激活，IL-22和IL-很重要 17生产。由于食物过敏和过敏反应是Dock8患者的主要特征，Dock8 缺乏症提供了一个有吸引力的疾病模型，用于识别食物过敏的基础机制。我们发现Dock8缺乏的患者的血清胰蛋白酶水平升高。 dock8 - / - 鼠标表现出夸张的Ige- 介导过敏到口服，但不是i.p.抗原挑战以及肠道MC扩展，我们显示既不是MC内固有的DOCK8缺乏的结果，也不是依赖IgE的结果。老鼠与 T细胞中DOCK8的选择性缺陷态dock8 - / - 小鼠，并且两者均表现出相似的肠道营养不良T 小肠道（Si）固有层（LP）的细胞dock8 - / - 小鼠的表达降低了IL22和IL17 并增加了IL4和IL13的表达。 Dock8缺乏Si上皮的表达降低抗菌肽（AMP）基因，但簇状细胞数量增加和IL25表达升高。治疗用SIL-22或口服抗生素鸡尾酒使肠道MC扩展归一化，这表明对由17型细胞因子缺乏驱动的营养不良。 IL-25和IL-4阻滞减少肠道MC负载和被动 Dock8 - / - 小鼠中的口服过敏反应，这表明IL-25的关键作用，促进2型细胞因子的产生由ILC2S和Th2细胞以及对MCS作用的IL-4。重要的是，粪便的无细菌（GF）WT接受者传统升高的Dock8 - / - 小鼠的微生物群移植（FMT）具有明显更大的肠道与来自常规升高的WT对照的FMT的GF WT受体相比，MC负载。因此，我们提出了研究研究了Dock8缺乏症中营养不良的机制可能会增加肠道MC载荷因此，促进过敏反应与经典食物过敏的患者有关。我们将检验以下假设，即1）由于缺陷而减少17型细胞因子的产生 Dock8缺乏的STAT3激活导致肠道营养不良，2）营养不良导致肠簇生产IL-25的细胞，该细胞驱动ILC2和Th2细胞产生2型细胞因子，以及3）IL-4 转弯，驱动肠道MC的膨胀和激活，从而促进过敏症摄入的抗原。我们将利用转基因小鼠，并利用我们对Dock8不足的患者的机会，以前有经典食物过敏儿童的特征良好的粪便样品来检验我们的假设。拟议的研究将描述免疫机制对于维持肠道如何重要微生物组调节肠道MC的扩张和激活，从而调节食物过敏的严重程度，因此确定预防和治疗食物过敏的新型策略。