大气细颗粒物毒性组分在呼吸道的定位分布及其引发呼吸道损伤及保护/适应性反应的分子作用机制

Epidemiological studies have demonstrated that long-term exposure to high concentrations of airborne fine particulate matter (PM2.5, aerodynamic diameter <2.5 µm) increases the riske of respiratory diseases and induce the adverse health effects in humans. However, we are still far from elucidating the mechanism that induce the adverse effects exerted by toxic compositions of PM2.5. In this project, the aim is to investigate the correlation between toxic compositions of PM2.5 and toxic effects in vivo and in vitro. Firslty, the physical and chemical characterizations of PM2.5 will be carried out using electron microscope, gaschromatography and others. Secondly, neutron activation- radiolabelled PM2.5 mixed with 14C isotopic labeling polycyclic aromatic hydrocarbons (PAHs) will be prepared. The C57BL/6 mice will be administrated with the different doses of labelled PM2.5 by nasal drops once perday. The location and distribution of PM2.5 and its toxic compostions in respiratory tract and other tissues will be exactly determined by nuclear techniques. Thirdly, wide type C57BL/6 mice, .SP-A knock-out (SP-A-/-), SP-D-/-, DDAH1-/- and DDAH1-TG C57BL/6 and A549 cells mice will be exposed to different doses of non-labelled PM2.5 for the indicated interval times. After exposure to PM2.5, the effects of PM2.5-induced injury and anti-injury responses in lung and cells will be carried out using biochemical and molecular immunohistochemical analyses. Moreover, the toxic compositions and chemical specieses of PM2.5 in lung and cells will be analyzed by synchrotron radiation techniques. In summary, our results obtained from this project can doucument the molecular mechanisms of toxic composition with different chemical species of PM2.5 in respiratory injury and protective and adaptive responses, which may provide novel insights into the mechanism of cytotoxicity and even pathogenesis of diseases associated with PM2.5 exposure.

大气细颗粒物（PM2.5）与呼吸道疾病的发生密切相关，已严重影响人类健康。针对PM2.5毒性组分和致毒机制的不确定性，本项目拟在PM2.5理化性质表征分析的基础上，应用中子活化对PM2.5的金属元素进行原位放射性标记，对其高毒性多环芳烃用14C进行化学标记；使用放射性标记的PM2.5暴露处理C57BL/6小鼠，精准测量PM2.5及组分在呼吸道和其他组织器官中的沉积和分布状况；通过不同剂量PM2.5暴露处理野生型、SP-A-/-、SP-D-/-、DDAH1-/-和DDAH1-TG C57BL/6小鼠和A549细胞，明确PM2.5所引发的肺组织和肺上皮细胞损伤/抗损伤反应，并结合同步辐射技术对肺组织和细胞内PM2.5毒性组分及其化学形态的分析，揭示PM2.5不同化学形态的毒性组分在其引发呼吸道损伤及保护/适应性反应的分子作用机制，为诠释细颗粒物毒性组分诱发的机体应答与损伤作用机理提供科学依据。

本项目完成了北京市大气颗粒物（PM10、PM2.5、PM1）的分级采集及其理化性质的系统表征分析；构建了模拟真实PM2.5暴露的动物模型和细胞模型；应用中子活化放射性标记和同步辐射技术等技术建立了实时、定量、高分辨、在体检测呼吸道组织和细胞内PM2.5毒性组分水平和化学形态的分析方法。揭示了不同粒径和理化性质的PM2.5暴露对呼吸道和心血管细胞形态、细胞周期和凋亡及自噬的影响；阐明了PM2.5暴露对肺脏和心脏组织和细胞的氧化应激、炎症反应等毒性效应的分子作用机制。利用放射性标记的PM2.5关键组分，揭示了PM2.5毒性组分在动物呼吸道、肺、心脏等组织器官的迁移分布状态；应用同步辐射微束X射线谱学/荧光分析（μ-XAFS/μ-XRF）等方法精准地检测了PM2.5毒性组分在呼吸道细胞表面和细胞内的定位分布特征及其化学形态。以野生型和基因敲除小鼠和细胞为研究对象，利用蛋白质组学、转录组学等技术获得了PM2.5暴露后肺脏组织和细胞的信号分子调控网络，全面剖析了PM2.5暴露引发呼吸道损伤及保护/适应性反应的分子作用机制，包括表观遗传学、氧化应激、免疫功能紊乱、细胞凋亡机制等。该项目建立的PM2.5毒理学评价方法，可为制定大气颗粒物污染相应的防治措施提供科学依据。项目取得了一批研究成果，已发表了标注项目号的SCI论文36篇、中文核心期刊7篇。项目负责人丁文军教授于2018年获国家科学技术进步二等奖（排名7），2019年获“国务院政府特殊津贴”、“中国科学院朱李月华优秀教师奖”和“中国科学院大学李佩教师奉献奖”。主要参与人张芳副教授2016年晋升教授。项目主要参与者侯小琳研究员，2017年获得“陕西省科学技术二等奖”、“陕西省科学院科学技术一等奖”；2019年获得放射分析和核化学“赫维西奖”和捷克化学学会“弗拉基米尔·马耶尔勋章”。培养10名博士生、13名硕士生。