多溴联苯醚致神经血管单元损伤的分子机制研究

PBDEs, a class of persistent organic pollutants, are ubiquitous in the environment. Neurotoxicity (such as developmental neurotoxicity) is one of their major adverse effects. Given that previous studies were mainly focused on neural cells and the effects on non-neural cells are largely unknown, this project is to investigate the neurotoxic effects of BDE-47, a predominant PBDE in the environmental and biological samples (particularly in human tissues), on the neurovascular unit (NVU) which consists of neuronal cells, glial cells, vascular endothelial cells, and pericytes. High-throughput single-cell RNA sequencing and bioinformatics will be applied to characterize the single-cell gene expression profiles of NYU from mice postnatally treated with BDE-47. With the comparisons among different types of cells or identical type of cells, we sought to clarify the shared and disparate responses of cells and cellular heterogeneity of NVU exposed to BDE-47. In addition, we will perform a number of in vitro and in vivo experiments to demonstrate the mechanisms of neuronal injury, neurovascular developmental defect and the impairment of blood-brain barrier with an emphasis on neurovascular interaction. This study will help to identify the key molecules, signaling pathways and their cellular localizations correlated with PBDEs exposure, which will provide valuable insights into the elucidation of neurotoxic effects, screening of biomarkers and biological monitoring of PBDEs.

PBDEs是环境中广泛存在的持久性有机污染物，神经系统损伤（如神经发育障碍）是PBDEs的主要毒性效应之一。已有的研究主要关注神经细胞损伤，缺乏对神经组织非神经细胞毒性的探讨。本项目将从神经血管单元角度，以环境和生物样品（尤其是人体）中主要的PBDE单体--BDE-47为研究对象，采用高通量单细胞RNA测序技术，分析出生早期BDE-47暴露引起的神经血管单元各组分（神经元、胶质细胞、血管内皮细胞和周细胞）的单细胞基因表达变化特征。基于异类细胞间和同类细胞间比较，探讨神经血管单元各组分毒性反应的异同点和细胞间的异质性。通过体外细胞和整体动物实验，深入研究PBDEs引起的神经元损伤、神经血管发育异常和血脑屏障功能障碍机制，重点关注对神经-血管相互作用的影响，识别神经系统损伤的关键分子事件、毒性通路及其细胞定位，为阐明PBDEs神经毒性机制、筛选生物标志物及生物监测提供重要依据。

有机阻燃剂的健康危害是当前环境科学领域的重点关注问题，神经系统损伤是其主要毒性效应，但机制尚待阐明。本项目围绕环境典型溴系阻燃剂PBDEs及其替代品磷系阻燃剂对神经血管单元的损伤作用及机制，通过探讨BDE-47、BDE-99、TPhP、TDCPP对血管生长、血脑屏障、神经细胞结构和功能以及神经行为的影响，描绘了低剂量暴露的毒效应特征。应用单细胞转录组测序等方法解析血管内皮细胞、神经元、神经干细胞、胶质细胞、巨噬细胞等神经血管单元组分细胞基因表达谱，比较各类细胞分子水平效应异同点，分析毒性反应异质性特征，识别血管内皮细胞、神经干细胞及小胶质细胞是神经毒性敏感效应靶标，提示以往研究重点关注神经元的局限性，丰富了阻燃剂类污染物的神经毒性靶点理论。发现血脑屏障损害、神经生长抑制和炎症激活是神经血管单元损害的主要效应，基于效应敏感细胞特征性通路深入探讨影响血管内皮细胞功能、神经血管交互作用以及炎症相关机制，阐明Nrf2介导氧化应激通路、神经导向分子通路和小胶质细胞介导炎症通路在神经血管单元损伤中的关键调节作用，筛选并鉴定Nrf2、VEGF、Sema、Il-1b等多个关键效应分子，有望开发成为有机阻燃剂环境监测和毒性评价的重要生物标志物。发现斑马鱼血管对典型溴系和磷系阻燃剂暴露极其敏感，可作为有机阻燃剂早期暴露和低剂量效应评价的首选模型。本项目从崭新角度全面、深入探讨神经毒作用模式，为构建环境典型有机阻燃剂的有害结局路径提供重要依据。