Department of Dermatology, Ehime University Graduate School of Medicine, Ehime, Japan.
Department of Dermatology, National Hospital Organization Shikoku Cancer Center, Ehime, Japan.
Biochim Biophys Acta Mol Basis Dis. 2020 May 1;1866(5):165719. doi: 10.1016/j.bbadis.2020.165719. Epub 2020 Feb 7.
In atopic diseases, the epithelium releases cytokines and chemokines that initiate skin inflammation. Atopic dermatitis (AD) is characterized by a disrupted epidermal barrier and is triggered or exacerbated by environmental stimuli such as house dust mite (HDM) allergens. The proinflammatory cytokine interleukin 33 (IL-33) plays an important role in the pathogenesis of AD, but how IL-33 production in keratinocytes is elicited by HDM is unknown. To that end, here we stimulated monolayer-cultured human keratinocytes and human living skin equivalents with Dermatophagoides pteronyssinus HDM extract to investigate its effects on IL-33 production from keratinocytes. The HDM extract induced intracellular expression of IL-33 and modulated its processing and maturation, triggering rapid IL-33 release from keratinocytes. Group 1 HDM allergen but not group 2 HDM allergen elicited IL-33 production. An ATP assay of keratinocyte culture supernatants revealed an acute and transient accumulation of extracellular ATP immediately after the HDM extract stimulation. Using the broad-spectrum P2 antagonist suramin, the specific purinergic receptor P2Y2 (P2RY2) antagonist AR-C118925XX, and P2RY2-specific siRNA, we discovered that the HDM extract-induced IL-33 expression was mainly dependent on extracellular ATP/P2Y2 signaling mediated by transactivation of epidermal growth factor receptor, followed by activation of the ERK kinase signaling pathway. Moreover, HDM extract-induced release of 25-kDa IL-33 from the keratinocytes depended on an extracellular ATP/P2 signaling-mediated intracellular Ca increase. Our study demonstrates the new mechanism controlling the induction and maturation of keratinocyte-produced IL-33 by HDM allergens, an innate immune process that might play a role in AD development or severity.
在特应性疾病中，上皮细胞释放细胞因子和趋化因子，引发皮肤炎症。特应性皮炎（AD）的特征是表皮屏障受损，并且受到环境刺激（如屋尘螨 [HDM] 过敏原）的触发或加剧。促炎细胞因子白细胞介素 33（IL-33）在 AD 的发病机制中起着重要作用，但 HDM 如何引发角质形成细胞产生 IL-33 尚不清楚。为此，我们用屋尘螨 HDM 提取物刺激单层培养的人角质形成细胞和人活体皮肤等效物，以研究其对角质形成细胞产生 IL-33 的影响。HDM 提取物诱导细胞内 IL-33 的表达，并调节其加工和成熟，从而触发角质形成细胞中 IL-33 的快速释放。第 1 组 HDM 过敏原而不是第 2 组 HDM 过敏原引发了 IL-33 的产生。对角质形成细胞培养上清液进行 ATP 测定显示，HDM 提取物刺激后立即急性和短暂地积累细胞外 ATP。使用广谱 P2 拮抗剂苏拉明、特异性嘌呤能受体 P2Y2（P2RY2）拮抗剂 AR-C118925XX 和 P2RY2 特异性 siRNA，我们发现 HDM 提取物诱导的 IL-33 表达主要依赖于细胞外 ATP/P2Y2 信号转导，该信号转导通过表皮生长因子受体的转激活介导，随后激活 ERK 激酶信号通路。此外，HDM 提取物诱导的 25kDa IL-33 从角质形成细胞中的释放依赖于细胞外 ATP/P2 信号介导的细胞内 Ca2+增加。我们的研究表明了控制 HDM 过敏原诱导和成熟角质形成细胞产生的 IL-33 的新机制，这是一种固有免疫过程，可能在 AD 的发展或严重程度中起作用。
