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：
10030396
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/10030396
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，通常是与肠道菌群失调有关。 IgE 对食物的敏感性本身不足以引起食物过敏反应。肠道 MC 负荷控制肠道通透性和全身抗原吸收，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 缺陷患者的主要特征，DOCK8 缺乏症为识别食物过敏的机制提供了一个有吸引力的疾病模型。我们发现 DOCK8 缺陷患者的血清类胰蛋白酶水平升高。 Dock8-/- 小鼠表现出夸张的 IgE- 介导的口服过敏反应，但不是腹膜内过敏。抗原激发，以及肠道 MC 扩张，我们展示了既不是 MC 内细胞内在 DOCK8 缺陷的结果，也不依赖于 IgE。小鼠与 T 细胞表型 Dock8-/- 小鼠中 DOCK8 选择性缺陷，并且两者均表现出相似的肠道菌群失调 T Dock8-/- 小鼠小肠 (SI) 固有层 (LP) 细胞中 Il22 和 Il17 的表达降低 Il4 和 Il13 的表达增加。 DOCK8缺陷的SI上皮细胞的表达减少抗菌肽 (AMP) 基因，但簇细胞数量增加且 Il25 表达升高。治疗 sIL-22 或口服抗生素混合物可以使肠道 MC 扩张正常化，这表明 17 型细胞因子缺乏导致的菌群失调。 IL-25 和 IL-4 阻断可减少肠道 MC 负荷和被动 Dock8-/- 小鼠出现口腔过敏反应，表明 IL-25 发挥着关键作用，可促进 2 型细胞因子的产生由 ILC2 和 Th2 细胞以及作用于 MC 的 IL-4 产生。重要的是，粪便的无菌 (GF) WT 接受者来自传统饲养的 Dock8-/- 小鼠的微生物群移植 (FMT) 具有显着更大的肠道功能 MC负荷与来自传统饲养的WT对照的FMT接受者的GF WT相比。因此，我们提出的研究调查了 DOCK8 缺陷导致的菌群失调可能增加肠道 MC 负荷的机制从而促进过敏反应与典型食物过敏患者相关。我们将检验以下假设：1) 由于缺陷导致 17 型细胞因子的产生减少 DOCK8 缺陷时 STAT3 激活导致肠道菌群失调，2）菌群失调导致肠道簇细胞产生 IL-25，驱动 ILC2 和 Th2 细胞产生 2 型细胞因子，以及 3) IL-4，转，驱动肠道 MC 扩张和激活，从而促进对摄入抗原的过敏反应。我们将利用转基因小鼠并利用我们接触 DOCK8 缺陷患者的机会之前从患有典型食物过敏的儿童身上采集的粪便样本来检验我们的假设。拟议的研究将描述免疫机制对于维持肠道的重要性微生物组调节肠道 MC 扩张和激活，从而调节食物过敏的严重程度，从而确定预防和治疗食物过敏的新策略。