PAEs经皮暴露对儿童特应性皮炎的影响及分子机制

Phthalates (PAEs) is one of the most ubiquitously occurring persistent organic pollutant in the environment. Atopic dermatitis is a common refractory disease related with immunity. The incidence rate of this disease among infants and children is about 10-20% or more. Epidemiological and experimental studies show that PAEs exposure is highly associated with the increased risk of atopic dermatitis. However, the specific molecular mechanisms are mostly unclear. The weaning period is critical for growth and development, during which the body is more sensitive to exogenous chemicals. This study aims to establish a model of weaned nude mice with atopic dermatitis exposed to PAEs through skin contact, to determine the influence of PAEs exposure on the formation of inflammatory skin foci and the changes of the typical indicators for atopic dermatitis in the serum. The oxidative stress level and the expression of inflammation-related genes in the peripheral blood monocytes from mice will be examined. The mediation effect for two signaling pathways related to epidermis injury, NF-κB and ERK/MAPK, in the development of atopic dermatitis will be elucidated through the pretreatment of antagonist for pathways. Besides, peripheral blood monocytes from patients with atopic dermatitis aged 0-12, will be prepared for PAEs exposure.Taken together, the inherent correlation between oxidative stress, inflammatory reaction, signaling pathways and PAEs-related atopic dermatitis will be clarified, and diverse functions of different PAEs will be elucidated eventually. This study could provide reference to the molecular mechanism for the promotion of atopic dermatitis by PAEs exposure in infants and children.

邻苯二甲酸酯（PAEs）是环境最常见的持久性有机物之一。特应性皮炎是免疫相关的常见难治病，儿童发病率约10-20%甚至更高。流行病学调查和实验研究表明，PAEs暴露与特应性皮炎存在密切联系，但分子机理研究报道较少。断乳期是生长发育关键期，对外源化学物异常敏感。本项目拟建立断乳特应性皮炎裸鼠模型，经皮暴露于PAEs，观察皮肤炎性灶形成及血液中关键指标的改变；检测小鼠外周血单核细胞氧化水平及炎症反应相关基因的表达；结合通路拮抗剂处理，阐明表皮损伤相关信号通路NF-κB和ERK/MAPK在特应性皮炎发展过程中的介导作用。在此基础上，结合0-12岁儿童患者外周血单核细胞暴露实验结果，最终揭示氧化应激、炎症反应及信号通路与PAEs相关特应性皮炎的内在关联，并甄别各种PAEs的作用差异。本项目有望为PAEs促进儿童特应性皮炎发展的分子机制提供参考。

邻苯二甲酸二异壬酯（DINP）是人工合成的邻苯二甲酸酯（PAEs）类化合物之一，作为氯乙烯塑料增塑剂，广泛应用于塑料制品的生产。流行病学调查及动物实验结果发现，DINP暴露与哮喘及特应性皮炎等过敏性疾病密切相关，但作用机制研究报道较少。朗格汉斯细胞（LCs）是表皮中的树突细胞（DC），介导外源物引起的多种皮肤疾患，而作用机制尚不明确。儿童处于生长发育关键期，对外源化学物异常敏感，本项目拟建立DINP经皮暴露的刚断乳 C57BL/6 和BALB/c 小鼠过敏性皮炎模型，阐明DINP对过敏性皮炎的促进作用，并以C57BL/6 小鼠为重点探讨作用机制。利用表皮LCs敲除型huLangerin-DTA小鼠阐明LCs在DINP促过敏性皮炎过程中的作用与分子机制。本项目分析了DINP暴露后过敏性皮炎小鼠模型皮损程度及耳厚度变化；制作耳组织切片，并进行H&E染色及TB染色观察组织病理学改变；免疫组化法检测耳组织TSLP的表达；ELISA法检测血清TSLP、S100A7水平及耳组织TSLP、IL-13、IL-5、IL-17蛋白表达水平；RT-PCR法检测淋巴结中TSLP、IL-17、IL-13、IL-4 mRNA表达水平；流式细胞术分析DINP暴露后鼠耳表皮LCs摄取异硫氰酸荧光素（FITC）水平，鼠耳表皮和颌下淋巴结中DC分化标志物CD86、CD40、CD80、PDL1和PDL2等表面分子的平均荧光强度，以及分析DINP暴露后huLangerin-DTA与同窝对照C57BL/6小鼠淋巴结中CD4+ IL-17+ T细胞（Th17）、CD4+ IFN-γ+ T细胞（Th1）、CD4+ IL-5+ T及CD4+ IL-13+ T细胞（Th2）数目变化情况。结果表明，DINP暴露加剧断乳期 C57BL/6 和BALB/c 小鼠过敏性皮炎症状，耳肿增加、嗜酸性粒细胞等炎症细胞增多、肥大细胞脱颗粒增多等、耳组织及血清中免疫指标变化。C57BL/6小鼠皮炎机制研究表明，DINP活化表皮LCs，促进LCs由表皮迁移至淋巴结，促进DC分化，诱导Th17、Th2细胞响应，产生高水平IL-17、IL-4、IL-5、IL-31等细胞因子及TSLP、S100A7，继而加剧小鼠过敏性皮炎。本项目有望为DINP等环境污染物经LCs介导促进过敏性皮炎的机制研究开辟一个新领域。