ABSTRACT

Staphylococcus aureus is a skin commensal microorganism commonly colonizing healthy humans. Nevertheless, S. aureus can also be responsible for cutaneous infections and contribute to flare-up of inflammatory skin diseases such as atopic dermatitis (AD), which is characterized by dysbiosis of the skin microbiota with S. aureus as the predominant species. However, the role of major virulence factors of this pathogen such as phenol-soluble modulin (PSM) toxins in epidermal inflammation remains poorly understood. Stimulation of primary human keratinocytes with sublytic concentrations of synthetic and purified PSM α3 resulted in upregulation of a large panel of pro-inflammatory chemokine and cytokine gene expression, including CXCL1, CXCL2, CXCL3, CXCL5, CXCL8, CCL20, IL-1α, IL-1β, IL-6, IL-36γ and TNF-α, while inducing the release of CXCL8, CCL20, TNF-α and IL-6. In addition, using S. aureus culture supernatant from mutants deleted from genes encoding either α-type PSMs or all PSM production, PSMs were shown to be the main factors of S. aureus secretome responsible for pro-inflammatory mediator induction in human keratinocytes. On the other hand, α-type PSM-containing supernatant triggered an intense induction of pro-inflammatory mediator expression and secretion during both topical and basal layer stimulation of an ex vivo model of human skin explants, a physiologically relevant model of pluristratified epidermis. Taken together, the results of this study show that PSMs and more specifically α-type PSMs are major virulence factors of S. aureus inducing a potent inflammatory response during infection of the human epidermis and could thereby contribute to AD flare-up through exacerbation of skin inflammation.

摘要

金黄色葡萄球菌是一种皮肤共生微生物，通常在健康人体内定殖。然而，金黄色葡萄球菌也可能导致皮肤感染并导致炎症性皮肤病如特应性皮炎 (AD) 的发作，其特征是金黄色葡萄球菌导致皮肤微生物群失调作为优势种。然而，这种病原体的主要毒力因子如酚溶性调节蛋白 (PSM) 毒素在表皮炎症中的作用仍然知之甚少。用亚溶解浓度的合成和纯化 PSM α3 刺激原代人角质形成细胞导致一大组促炎趋化因子和细胞因子基因表达上调，包括 CXCL1、CXCL2、CXCL3、CXCL5、CXCL8、CCL20、IL-1α、IL- 1β、IL-6、IL-36γ 和 TNF-α，同时诱导 CXCL8、CCL20、TNF-α 和 IL-6 的释放。此外，使用从编码 α 型 PSM 或所有 PSM 产生的基因中删除的突变体的金黄色葡萄球菌培养上清液，显示 PSM 是金黄色葡萄球菌的主要因素负责人角质形成细胞中促炎介质诱导的分泌组。另一方面，含有α-型 PSM 的上清液在人皮肤外植体的离体模型（一种多分层表皮的生理相关模型）的局部和基底层刺激过程中引发了促炎介质表达和分泌的强烈诱导。总之，本研究的结果表明，PSMs，更具体地说是 α 型 PSMs 是金黄色葡萄球菌的主要毒力因子，在感染人类表皮期间诱导强烈的炎症反应，从而可能通过皮肤恶化导致 AD 发作。炎。