Mechanisms of enhanced food allergy by S. aureus skin colonization in Atopic Dermatitis

特应性皮炎中金黄色葡萄球菌皮肤定植增强食物过敏的机制

• 批准号: 10638821
• 负责人: RAIF SALIM GEHA
• 金额: $ 80.01万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-22 至 2028-02-29
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10638821
• 关键词: Address; Affinity; Allergic; Allergic Reaction; Anaphylaxis; Antibodies; Antigens; Atopic Dermatitis; Attenuated; Bacteria; Basophils; Binding; CASP8 gene; Caspase; Cells; Data; Dendritic Cells; Disease; Epithelial Cells; Epithelium; Event; Exposure to; Food; Food Hypersensitivity; IL3 Gene; IgE; In Vitro; Inflammation; Interleukin-4; Intestinal Absorption; Intestinal permeability; Mediating; Mediator; Monoclonal Antibodies; Mus; Myosin Light Chain Kinase; Oral; Ovalbumin; Pathway interactions; Patients; Predisposition; Proteins; Role; Scheme; Serum; Signal Transduction; Skin; Skin colonization; Staphylococcal Enterotoxin B; Staphylococcus aureus; Stromal Cells; Superantigens; T-Lymphocyte; TNFRSF5 gene; Technical Expertise; Testing; Tight Junctions; Toxin; absorption; antigen challenge; draining lymph node; food antigen; in vivo; inhibitor; intestinal barrier; intestinal epithelium; keratinocyte; mast cell; mouse model; novel therapeutics; passive sensitization; receptor; recruit; response; small molecule; synergism

Abstract The skin of AD patients is often colonized by S. aureus strains that produce superantigens (SAg), primarily staphylococcal enterotoxin B (SEB). There is a positive association between S. aureus skin colonization and food allergy in AD. The mechanism of this association is unknown. We have made the observation that epicutaneous (EC) application of ovalbumin (OVA) and SAg producer S. aureus, or OVA and SEB, results in the selective exaggeration of anaphylaxis to oral challenge with OVA compared to EC application of OVA alone. Moreover, it results in exaggerated systemic anaphylaxis to oral challenge with BSA-TNP in mice passively sensitized with IgE anti-TNP, indicating that the enhancement of food anaphylaxis was non-antigen-specific and determined by factors beyond differences in IgE Ab levels or affinity. We propose to dissect the mechanisms of SEB enhancement of IgE mediated oral anaphylaxis. Preliminary data show that enhanced susceptibility to oral anaphylaxis in mice EC exposed to OVA+SEB is associated with elevated levels of serum IL-4, dependent on IL-4 and IL-4R expression by intestinal epithelial cells (IECs),and accompanied by increased intestinal permeability (IP). Enhanced susceptibility is inhibited by Divertin, a small molecule that suppresses intestinal absorption of antigen via the paracellular pathway by blocking the recruitment of myosin light chain kinase (MLCK) to the peri-junctional actinomyosin ring, where it disrupts epithelial tight junctions. This suggests a critical role for MLCK in food allergy. In addition, the data show that EC application of SEB causes a massive influx of basophils in skin-draining lymph nodes (dLNs) that was dependent on CD40 keratinocyte (KC)-derived IL-33, and T cells. The recruited basophils enhanced the ability of dendritic cells (DCs) from skin dLNs to drive Th2 polarization. Pretreatment of DCs in vitro with IL-4 also promoted their capacity to drive Th2 polarization. We propose to test the hypothesis that SEB from S. aureus that colonizes AD skin binds to CD40 on KCs and triggers caspase 8 mediated cleavage and release of bioactive IL-33 which induces IL-3 release by T cells leading to recruitment of basophils in dLNs. There, basophil-derived IL-4 promotes the Th2 polarizing ability of DCs that have captured antigen encountered in the skin. These events drive a rise in systemic levels of Th2 derived IL-4. Increased IL-4 signaling in IECs synergizes with mediators released by MCs to promote MLCK dependent barrier loss by causing redistribution of tight junction proteins. The resulting increased antigen absorption triggers a forward amplification cycle of MC activation that exaggerates allergy to foods against which the patient has been sensitized. The studies proposed will define the mechanisms by which S. aureus skin colonization aggravates food allergy and will uncover a central role of MLCK in this disease. They may lead to novel therapies for food allergy that would target S. aureus skin colonization, CD40 in skin, IL-33 and MLCK.

摘要 AD患者的皮肤经常被S.产生超抗原（SAg）的金黄色葡萄球菌菌株，主要 葡萄球菌肠毒素B（SE B）。S.金黄色葡萄球菌皮肤定植和 AD中的食物过敏这种关联的机制尚不清楚。我们观察到， 表皮（EC）应用卵清蛋白（OVA）和SAg生产者S.金黄色葡萄球菌，或OVA和SEB，导致 与单独使用OVA的EC应用相比，选择性加重了对用OVA口服激发的过敏反应。 此外，它导致小鼠被动地对BSA-TNP口服激发的全身过敏反应增强 用IgE抗TNP致敏，表明食物过敏反应的增强是非抗原特异性的， 由IgE Ab水平或亲和力差异以外的因素决定。我们建议剖析 SEB增强IgE介导的口腔过敏反应。 初步数据显示，暴露于OVA+SEB的小鼠EC对口服过敏反应的敏感性增强 与血清IL-4水平升高相关，依赖于肠上皮细胞表达IL-4和IL-4 R β 细胞（IEC），并伴有肠通透性增加（IP）。增强的敏感性被抑制， Divertin是一种小分子，通过细胞旁途径抑制抗原的肠道吸收， 阻断肌球蛋白轻链激酶（MLCK）募集到连接周围的放线菌球蛋白环， 破坏上皮紧密连接。这表明MLCK在食物过敏中起关键作用。此外，数据显示， SEB的EC应用导致皮肤引流淋巴结（dLN）中嗜碱性粒细胞的大量流入， 依赖于CD 40角质形成细胞（KC）衍生的IL-33和T细胞。募集的嗜碱性粒细胞增强了 的树突状细胞（DC）从皮肤dLN驱动Th 2极化。用IL-4在体外预处理DC也 促进了它们驱动Th 2极化的能力。 我们提出了一个假设，即SEB从S。定植于AD皮肤的金黄色葡萄球菌结合KC上的CD 40 并触发胱天蛋白酶8介导的生物活性IL-33的切割和释放，其诱导T细胞释放IL-3 导致dLN中嗜碱性粒细胞的募集。在那里，嗜碱性粒细胞来源的IL-4促进Th 2极化能力， 已捕获皮肤中遇到的抗原的DC。这些事件促使Th 2的系统水平升高 衍生的IL-4。IEC中增加的IL-4信号传导与MC释放的介质协同促进MLCK 通过引起紧密连接蛋白的重新分布来依赖屏障损失。由此产生的抗原增加 吸收触发了MC激活的正向放大循环，从而夸大了对食物的过敏， 病人已经过敏了 这些研究将明确S.金黄色葡萄球菌皮肤定植污染食物 并将揭示MLCK在这种疾病中的核心作用。它们可能会导致食物过敏的新疗法 这将针对S。金黄色葡萄球菌皮肤定植、皮肤中的CD 40、IL-33和MLCK。