The role of bacterial toxins in human skin disease.

描述（由申请人提供）：特应性皮炎（AD）是一种瘙痒性慢性炎症性皮肤病，与显著的发病率和职业残疾相关，影响美国17%的儿童和近2%的成年人。研究强调了金黄色葡萄球菌感染、定植和毒素产生在AD严重程度/恶化中的重要性。这项竞争更新R01资助申请（5 R01 AR41256-18）的总体目标将是确定产毒素金黄色葡萄球菌在AD患者体内的定植如何改变皮肤的炎症反应。此外，我们还希望研究金黄色葡萄球菌与Th2环境联合产生毒素增强皮肤炎症的新机制。我们以前对葡萄球菌超抗原的研究主要集中在皮肤中这些毒素对单核细胞的激活。新的初步数据表明，葡萄球菌超抗原（staphylococcal enterotoxin B， SEB）也直接作用于角质形成细胞，并通过诱导促炎和Th2细胞皮肤归巢趋化因子参与皮肤炎症。SEB刺激的人角质形成细胞的全球基因表达谱显示，SEB激活了蛋白酶，并表明SEB可能通过影响过敏原吸收和炎症的细胞外基质的变化而增强过敏性皮肤致敏，我们将在本提议中对此进行探讨。我们提出了Th2细胞因子增强角质细胞对SEB反应的证据，并提出这可能是通过与SEB诱导途径的协同作用和/或SEB特异性受体的表达增加而发生的，因此放大了特应性皮肤的炎症反应。最后，我们证明葡萄球菌孔形成α -毒素，通常与金黄色葡萄球菌产生超抗原相一致，可以通过促进葡萄球菌产物通过毒素诱导的孔进入细胞内，从而允许细胞内受体参与，从而增强对葡萄球菌产物的反应。Th2细胞因子可能增加α -毒素与角化细胞的结合，影响孔的形成并增强角化细胞对葡萄球菌产物的反应。该提案的具体目的是：首先，确定葡萄球菌超抗原对角化细胞炎症反应的影响，重点关注超抗原激活的人角化细胞和来自产生超抗原的金黄色葡萄球菌定植的AD患者皮肤样本的基因和蛋白质表达谱，以及表皮应用SEB后小鼠皮肤的体内炎症反应和过敏原吸收；其次，通过分析角质形成细胞中基因和蛋白表达的变化，评估STAT6转基因小鼠对SEB的炎症反应，探索SEB和Th2细胞因子参与的信号通路，并确定特异性SEB受体，探索Th2细胞因子在皮肤对葡萄球菌超抗原反应中的调节作用；最后，研究葡萄球菌α -毒素在角化细胞对SEB/其他葡萄球菌产物反应中的免疫调节作用。研究可能会确定控制由葡萄球菌毒素和特应性引起的皮肤炎症的治疗方法。

DESCRIPTION (provided by applicant): Atopic dermatitis (AD) is a pruritic chronic inflammatory skin disease associated with significant morbidity and occupational disability affecting 17% of children and nearly 2% of adults in the U.S. Studies have highlighted the importance of S. aureus infection, colonization and toxin production in AD severity/exacerbation. The overall goal of this competing renewal R01 grant application (5 R01 AR41256-18) will be to determine how colonization with toxin producing S. aureus in AD patients alters inflammatory response in the skin. As well, we wish to investigate novel mechanisms by which Th2 environment in combination with toxin production by S. aureus enhance skin inflammation. Our previous studies of staphylococcal superantigens primarily focused on mononuclear cell activation by these toxins in the skin. New preliminary data show that staphylococcal superantigens (staphylococcal enterotoxin B, SEB) also exert effects directly on keratinocytes and contribute to the skin inflammation by inducing proinflammatory and Th2 cell skin homing chemokines. Global gene expression profiling of SEB stimulated human keratinocytes demonstrates protease activation by SEB and suggests that SEB may enhance allergic skin sensitization due to changes in extracellular matrix that can affect allergen absorption and inflammation, which we will explore in this proposal. We present evidence for Th2 cytokine potentiation of keratinocyte responses to SEB and propose that this occurs either through synergism with SEB induced pathways and/or increased expression of a specific receptor to SEB, therefore amplifying inflammatory responses in atopic skin. Finally, we demonstrate that staphylococcal pore forming alpha-toxin, that often coincides with superantigen production by S. aureus, can potentiate responses to staphylococcal products by facilitating their intracellular entry via toxin-induced pores, thereby allowing the engagement of intracellular receptors. Th2 cytokines may increase alpha-toxin binding to keratinocytes, affecting pore formation and intensifying keratinocyte responses to staphylococcal products. The specific aims of this proposal will be: first, to determine the effects of staphylococcal superantigens on inflammatory responses of keratinocytes, focusing on gene and protein expression profiling in superantigen activated human keratinocytes and skin samples from AD patients colonized with superantigen producing S. aureus, in vivo inflammatory responses and allergen absorption in murine skin following epicutaneous application of SEB; second, to explore the modulatory role of Th2 cytokines in responses to staphylococcal superantigens in the skin by analyzing changes in gene and protein expression in keratinocytes, assessing inflammatory responses to SEB in STAT6 transgenic mice, exploring signaling pathways engaged by SEB and Th2 cytokines, and defining the specific SEB receptor; finally, to investigate the immunomodulatory role of staphylococcal alpha-toxin in keratinocyte responses to SEB/other staphylococcal products. Studies will likely identify therapeutic approaches in the control of skin inflammation initiated by staphylococcal toxins and atopy. PUBLIC HEALTH RELEVANCE: Staphylococcus aureus has emerged as a worldwide pathogen that is rapidly increasing in prevalence and causing serious illness. The specific objectives of this study will be to determine the mechanisms by which staphylococcal toxins cause human skin disease particularly atopic dermatitis which is the most common cause of chronic skin disease in children and often persist into adulthood. Data from this grant may lead to more effective treatment strategies for this serious public health issue.