PM2.5特异菌群激活TLR/TSLP天然免疫通路诱发哮喘的机制

PM2.5 is the key component of the air pollutant in causing the asthma. Biological pollutants in air pollutants, including bacteria, viruses, fungi, etc. accounted for 25%. The growth and propagation of the microbiota is closely related to the climatic factors such as temperature and humidity, which can enter and colonize in the human body with the breath and cause disease.Guangzhou is a subtropical marine climate city, in which the distribution, characteristics and pathogenicity of microbiota in PM2.5 are not fully understood.We adopt a multi-disciplinary research and combine environmental hygiene, metagenomic and comparative genomic science, immunology and pathogenic biology methods to analysis the microbiota differences among PM2.5, soil, repiratory tract among animals and asthma patients in Guanghzou, in order to find out specific microbiota that can colonize in the repiratory tract. The key pathway is that TLR, a pattern recognition receptor, can recognize the microbiota and induce TSLP, which lead to asthma. We aim to find the specific microbiota or virulence factors, which can activate TLR/TSLP pathway, using luciferase report gene, quantitative PCR, Crisper/Cas9 etc. methods. At last, TSLP gene knockout mice and asthma model mice are used to study the roles of microbiota in causing asthma and antibacterial effects of serogroup in the prevention and treatment of asthma.Our research will reveal the new pathogenic mechanism of PM2.5 and provide a new idea for the prevention and treatment of asthema caused by PM2.5 in Guangzhou.

PM2.5是大气污染物中导致哮喘的关键成分，其中菌群（细菌、病毒、真菌）等生物性污染物含量占25%。菌群的生长繁殖与温湿度等气候因素密切相关，随呼吸进入人体，部分菌群得以定植并引起疾病发生。广州作为南亚热带海洋性气候城市，其PM2.5中菌群的分布、特征和致病性并不完全清楚。本课题通过环境卫生学、宏基因组与比较基因组学、免疫学和病原生物学方法，分析广州大气PM2.5、土壤、动物和哮喘患者呼吸道中的菌群差异，发现可定植呼吸道的特异菌群；并以模式识别受体TLR识别菌群相关分子模式从而诱导TSLP导致哮喘通路为核心，通过荧光素酶报告基因、定量PCR、Crisper/Cas9等方法寻找可激活TLR/TSLP的菌群或毒力因子；利用TSLP基因敲除小鼠和哮喘模型小鼠研究菌群的致哮喘作用以及抗菌群血清的防治作用，为揭示广州地区PM2.5的致病作用提出新机制，并为发明PM2.5所致哮喘的防治方法提供新思路。

项目背景：.慢性炎症介导的气道高反应性是哮喘主要发病机制。有研究表明大气中PM2.5的浓度每增加10mg/m3，儿童因哮喘住院率增加21%。PM2.5能够吸附有毒物质并到达肺深部，且PM2.5中多种成分均能引发哮喘。纳米颗粒常被PM2.5携带，极易协同损害健康。部分纳米颗粒如SiO2和Co3O4等能够导致哮喘。呼吸道合胞病毒（RSV）与哮喘发生密切相关，RSV隐性感染诱发哮喘的概率远远高于其他病毒感染，新生儿出现RSV感染可以增加幼儿期哮喘的发病风险。本研究通过对PM2.5、纳米颗粒物和RNA病毒的体外研究，观察三者对炎症换页哮喘相关天然免疫功能的交互作用。..主要研究内容：.（1）广州PM2.5中所含菌群测定；.（2）PM2.5诱导A549细胞表达哮喘模相关因子TSLP；.（3）纳米SiO2协同IL-1β对A549细胞IL-1β下游信号通路的激活；.（4）纳米Co3O4对VSV诱导A549抗病毒天然免疫的影响；.（5）PM2.5对VSV诱导 A549抗病毒天然免疫的影响；.重要结果：.（1）广州PM2.5中变形菌门,拟杆菌门和厚壁菌门较丰富，相对丰富度达到了80%以上。.（2）SiO2协同IL-1β促进ERK和I-κB磷酸化，诱导A549细胞过表达IL-1β和IL-6，并抑制A549细胞活性。.（3）Co3O4促进VSV在A549细胞中复制，并协同VSV诱导IRF-3非磷酸化降解而抑制IFN-β、IL-1和IL-6在A549细胞中的表达。.（4）PM2.5能够通过诱导A549细胞过表达TRIM73从而泛素化降解VSV诱导的p-IRF-3进而抑制IFN-β、ISG15、CXCL-10和CCL-5的表达，并促进VSV在A549细胞内的增殖。.（5）PM2.5能够通过诱导A549细胞的自噬作用从而促进RSV病毒的增殖。.（6）PM能够协同诱导C57BL/6J小鼠哮喘发生。..研究的科学意义：.通过以上机制研究，未来有希望通过某种蛋白抑制药物而达到阻碍纳米颗粒或PM2.5促进病毒复制、诱导炎症反应的目的，进而减少PM2.5引发哮喘的几率。