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.

抽象的 AD 患者的皮肤经常被产生超抗原 (SAg) 的金黄色葡萄球菌菌株定殖，主要是 金黄色葡萄球菌肠毒素 B (SEB) 与金黄色葡萄球菌皮肤定植呈正相关。 AD 中的食物过敏这种关联的机制尚不清楚。 卵清蛋白 (OVA) 和 SAg 生产者金黄色葡萄球菌或 OVA 和 SEB 的表皮 (EC) 应用会导致 与单独使用 OVA 的 EC 应用相比，OVA 口服刺激选择性夸大过敏反应。 此外，它会导致小鼠被动地对 BSA-TNP 口服刺激产生过度的全身过敏反应 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，并且 由 IgE Ab 水平或亲和力差异以外的因素决定。我们建议剖析其机制。 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 对口腔过敏反应的易感性增强 与血清 IL-4 水平升高相关，依赖于肠上皮的 IL-4 和 IL-4Rα 表达 细胞（IEC），并伴随着肠道通透性（IP）增强的敏感性受到抑制。 Divertin，一种小分子，通过细胞旁途径抑制肠道对抗原的吸收 阻断肌球蛋白轻链激酶 (MLCK) 向连接周围放线肌球蛋白环的募集， 此外，数据显示，MLCK 会破坏上皮紧密连接。 EC 应用 SEB 会导致嗜碱性粒细胞大量涌入皮肤引流淋巴结 (dLN)， 依赖于 CD40 角质形成细胞 (KC) 衍生的 IL-33 和招募的嗜碱性粒细胞的 T 细胞增强了这种能力。 还用 IL-4 对皮肤 dLN 中的树突状细胞 (DC) 进行体外预​​处理以驱动 Th2 极化。 提高了它们驱动Th2极化的能力。 我们建议检验以下假设：来自定植 AD 皮肤的金黄色葡萄球菌的 SEB 与 KC 上的 CD40 结合 并触发 caspase 8 介导的生物活性 IL-33 的裂解和释放，从而诱导 T 细胞释放 IL-3 导致 dLN 中嗜碱性粒细胞的募集，其中嗜碱性粒细胞衍生的 IL-4 促进 Th2 极化能力。 捕获皮肤中遇到的抗原的 DC 会导致 Th2 的全身水平升高。 IEC 中IL-4 信号传导的增加与 MC 释放的介质协同作用，促进 MLCK 通过引起紧密连接蛋白的重新分布而导致的依赖性屏障丧失，从而导致抗原增加。 吸收会触发 MC 激活的前向放大循环，从而夸大对食物的过敏 病人已经过敏了。 拟议的研究将确定金黄色葡萄球菌皮肤定植加剧食物恶化的机制 过敏，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。 其目标是金黄色葡萄球菌皮肤定植、皮肤中的 CD40、IL-33 和 MLCK。