大气多环芳烃对心血管内皮细胞炎症的影响及潜在的分子机制

It has been demonstrated that ambient fine particulate matter (PM2.5) can impact the cardiopulmonary health. Polycyclic aromatic hydrocarbons (PAHs), which are the key toxic components of ambient PM2.5 in China, have been proven by numerous studies to be harmful to residents' respiratory system. But it is currently unclear what effects they may pose to the cardiovascular system. In this project, the inflammatory biomarkers of IL8, IL6 and MCP-1 will be employed to study the inflammatory effects of the 16 kinds of priority PAHs on the human umbilical vein endothelial cells (HUVEC) and explore the dose-effect relationships. The aryl hydrocarbon receptor (AHR), as the target protein of endothelial cells responding to PAHs, will be knockdowned and/or overexpressed by means of RNAi and molecular genetics in the HUVEC to set up the stable cell lines, HUVEC-KD and HUVEC-KD-OE, which will be used as the cell models in the subsequent tests. The interactions between PAHs and AHR and the key regulatory protein, NF-ĸB, and the downstream inflammatory factors will be explored with the cells of HUVEC-KD and HUVEC-KD-OE to uncover the molecular mechanisms underlying the inflammation caused by the PAHs in the endothelial cells. The size distribution of PAHs in the different fraction of fine particulate matter collected from actual air environments will be characterized by GC-MS. The inflammatory effects of the PAHs extracted from different size- fractioned fine particles, especially for the PM0.1, which were demonstrated to be able to pass through the respiratory barrier, will also be explored with the HUVEC. The results of this project can expand our understandings in the adverse effects of PAHs on public health from their acting in cardiovascular health. In addition, it can also provide fundamental scientific data for us to assess the potential risks of airborne PAHs to the cardiovascular health.

细颗粒物影响呼吸和心血管系统健康，多环芳烃是我国细粒子中特征性关键致毒组分，其对呼吸系统危害已被大量前期研究证实，但对心血管系统的健康有何影响，目前尚不清楚。本项目拟针对16种优控多环芳烃，以人脐静脉内皮细胞为细胞模型，以IL8、IL6和MCP1为生物标志物，研究其对内皮细胞炎症的影响，并建立剂量-效应关系；以芳香烃受体为细胞应答多环芳烃的目标蛋白，敲减或过表达内皮细胞的芳香烃受体基因，建立稳定细胞株等为细胞模型，从“多环芳烃→芳香烃受体→炎症关键调控蛋白NF-ĸB→下游炎症因子”的作用上，揭示多环芳烃致内皮细胞炎症的分子机制；分粒径采集分析实际环境大气细颗粒样品中的多环芳烃组成，并探讨不同粒径，特别是能透过肺泡壁生理屏障的超细粒子样品中多环芳烃对内皮细胞的炎性毒性。本项目研究有助于从心血管系统健康影响的角度拓展对多环芳烃健康危害的认识；并为评价多环芳烃对心血管系统健康的影响提供科学依据。

大气细颗粒物（PM2.5）影响心血管系统的健康，多环芳烃（PAH）是我国大气PM2.5的特征性组分，其对心血管系统的健康有何影响，目前尚不清楚。本项目以心血管病发生发展的关键病理环节——内皮细胞炎症为切入点，以人脐静脉内皮细胞为细胞模型，研究PM2.5及其组分PAH和细菌脂多糖（LPS）对内皮细胞炎症的影响与机制。经过4年的研究，首先，建立了多种PAH标准物影响内皮细胞炎症因子表达的剂量-效应关系：低剂量PAH可抑制内皮细胞炎症因子的表达与释放，高剂量PAH则促进炎症因子的表达与释放；建立了LPS诱导内皮细胞炎症因子表达的剂量-效应关系：内皮细胞炎症因子的表达随LPS暴露浓度增加而增加；发现低剂量PAH能抑制LPS诱导内皮细胞炎症因子的表达。其次，揭示了芳香烃受体、MAPK通路的关键蛋白（p38、JNK1/2和ERK1/2）和NF-κB在PAH或LPS单独或其联合作用下影响内皮细胞炎症中的作用机制。第三，阐释了大气PM2.5致内皮细胞炎症的分子机制，结果表明：大气环境剂量的PAH暴露不能解析PM2.5致内皮细胞炎症的生物与化学机制，即PM2.5致内皮细胞炎症的关键毒害组分另有其他，还需深入细致的研究以精确识别出。第四，揭示了PAH和LPS单独或联合作用下影响内皮细胞自噬的分子机制；第五，阐释了大气PM2.5诱导内皮细胞内质网应激和干扰内皮细胞自噬的分子机制；第六，阐明了大气PM2.5致内皮细胞铁死亡的分子机制。本项目的研究结果，拓展了对大气PAH、LPS和PM2.5影响内皮细胞炎症和自噬的分子机制，以及大气PM2.5致内皮细胞内质网应激和铁死亡分子机制的认识，可为科学评价大气PM2.5及其PAH和LPS影响心血管系统的健康提供基础科学数据，并为相关部门的科学决策，特别是科学地预防与控制大气PM2.5及其PAH和LPS对心血管系统健康的潜在风险提供科学依据。