PM2.5所致肺损伤中能量代谢通路扰动及相关表遗传调控机制研究

Fine particulate matter (PM2.5) in ambient environment is associated with lung dysfunction, however, the underlying mechanism is still unclear. Based on transcriptional assay coupled with metabolomics analysis, we found that energy metabolism pathway is involved in the early-stage pulmonary disorders induced by PM2.5 and its components. Here we propose the hypothesis that the disturbance of energy metabolism pathway is an up-stream event in the progression of PM2.5 induced pulmonary lesions. Exposure of PM2.5 and its components lead to dysfunction of mitochondria and disturbance of epigenetics, ultimately leading to pulmonary damages..We are trying to validate our hypothesis upon three levels by detecting the levels of key molecules involved in citrate metabolism, expression of acetylation of histone 3, dysfunction of mitochondria in vitro; in animal models dynamic nasal PM2.5 and its components inhalation mice mode; the correlation between energy metabolism pathway molecular markers and PM2.5 exposure will be validated in human blood samples. We are trying to establish the dose-response curve of energy metabolism key points in response to PM2.5 and its components exposures. The potential therapeutic small molecular metabolites could be identified by metabolomics analysis, which could help to rescue the disturbance of energy metabolism induced by PM2.5 exposure. These studies could facilitate the integrative understanding of pulmonary toxic mechanism induced by PM2.5, as well as the identification of early biomarkers.

流行病学研究发现肺部疾病高发与PM2.5污染密切相关，但详尽分子机制未明。课题组前期研究发现PM2.5干扰细胞能量代谢通路引起线粒体功能下降，最终导致肺损伤。据此提出如下科学假说：能量代谢通路扰动可能是PM2.5及其组分导致肺损伤的早期分子事件；是连接PM2.5暴露、线粒体功能损伤、表遗传调控的关键分子通路。拟通过代谢组学对肺组织细胞中能量代谢代谢通路关键分子扰动；组蛋白修饰位点筛选、ChIP-seq对细胞表遗传修饰调控；以及线粒体损伤标志物进行检测；建立PM2.5及组分长期动态吸入染毒小鼠模型；定组人群研究血样分析，从细胞、动物和人群三个水平，对以上科研假说进行验证。发现PM2.5及其组分暴露引起肺损伤的早期标志分子；明确能量代谢通路对细胞表遗修饰传的调控；通过代谢组学技术发现潜在具有修复能量代谢通路能力的小分子化合物，探讨PM2.5及其组分致肺损伤的早期的分子机制。

本项目通过研究大气细颗粒物（fine particulate matter, PM2.5）及关键组分的暴露水平和特征，以及在此暴露情况下，探讨肺组织能量代谢通路扰动的毒作用机制与表观遗传的关键标志物，筛选并验证小分子代谢物作为PM2.5及其组分暴露所致的肺损伤效应标志及治疗靶点的可行性。完成如下研究目标：1）利用代谢组学及miRNA芯片筛选PM2.5及其金属组分暴露引起肺损伤的早期分子标志；2）明确PM2.5及其金属组分对细胞能量代谢通路的扰动；3）通过代谢组学技术筛选对能量代谢通路具有潜在修复能力的小分子化合物。研究结果发现：1）利用构建的体内外暴露模型发现，PM2.5暴露导致上皮标志物表达减少，间充质标志物表达水平和细胞侵袭能力增加；PM2.5主要金属组分铝颗粒在体外或体内均可引起线粒体依赖性细胞凋亡和氧化应激；筛选了多个在铝颗粒暴露模型中具有调控作用的miRNAs。2）PM2.5暴露导致ATP柠檬酸裂解酶（ACLY）表达水平增高，而敲减ACLY可以抑制PM2.5暴露诱导的HBE细胞的上皮细胞-间充质转化（EMT）、迁移和侵袭能力的增加。3）抗氧化剂乙酰基L-肉碱能够恢复铝颗粒对线粒体复合体I，IV和V相关基因表达水平的影响，拮抗纳米氧化铝暴露导致的体内外模型凋亡和氧化损伤作用。本项目结合代谢组学分析识别出关键代谢分子，其通过修复能量代谢通路，缓解PM2.5及其毒性组分引起的呼吸系统损伤，为大气污染的个体防护提供理论依据。项目负责人受邀参加全国毒理学大会、环境与健康大会、等本领域内重要学术会议，并做分会场报告。课题组成员先后参加亚洲环境诱变剂会议，并做分会场报告3人次。相关成果在Advanced Science、Environ Int、Environ Pollut、Ecotoxicol Environ Saf 等SCI期刊发表论文6篇，先后培养硕士研究生3名。