Wnt5a介导的非经典Wnt-YAP/TAZ通路在环境PAHs暴露致气道上皮损伤和肺功能下降中的作用机制研究

Polycyclic aromatic hydrocarbons (PAHs) are considered as one kind of the most widespread organic environmental pollutants. Our previous results indicated that PAH exposures might reduce lung function by injuring airway epithelium. However, the underlying mechanisms remain unclear. Wnt5a-mediated non-canonical Wnt-YAP/TAZ pathway was found to affect tissue repair by antagonizing canonical Wnt pathway, but the role of Wnt5a-mediated non-canonical Wnt-YAP/TAZ pathway in airway epithelial injury and lung function decline induced by PAH exposures was unknown to date. In this study, we will conduct in vitro experiments using human bronchial epithelial cells which were treated with different doses of PAHs (using BaP, a suitable surrogate marker to represent mixtures of PAHs). Concentrations of the non-canonical Wnt-YAP/TAZ pathway related biomarkers were measured at different time points to explore the dose-response and time-response relationships. We will further perform a toxicological study by using normal mice, Wnt5a antagonist treated mice and recombinant Wnt5a protein treated mice, to learn the effect of Wnt5a-mediated non-canonical Wnt-YAP/TAZ pathway on airway epithelium and ventilatory function after BaP exposure. Finally, we will conduct an epidemiological study of 240 participants from the Wuhan-Zhuhai cohort. We will detect concentrations of individual PAH exposures and the pathway related biomarkers, and then link them to levels of airway epithelial injury and lung function parameters, which enables us to investigate relationships of the non-canonical Wnt-YAP/TAZ pathway with PAH exposures and airway disorders.

多环芳烃（PAHs）是常见的环境污染物之一。本课题组前期研究提示，PAHs可通过损伤气道上皮影响肺功能，但机制不清。组织修复异常是气道上皮损伤持续和多种肺部疾病发生的关键。研究发现Wnt5a介导的非经典Wnt-YAP/TAZ通路可通过抑制组织修复重要信号途径而影响修复功能，但该通路在PAHs暴露致气道上皮损伤和肺功能下降中的作用尚无报道。本研究拟采用不同剂量PAHs进行体内外染毒实验，测定不同时间点非经典Wnt-YAP/TAZ通路相关配体Wnt5a及关键因子表达水平，明确其剂量-效应和时间-效应关系；通过拮抗和补充Wnt5a的方法，探讨该通路在PAHs暴露损伤气道上皮和通气功能中的作用；同时测定已建立的队列人群个体PAHs暴露和非经典Wnt-YAP/TAZ通路关键指标的浓度，结合气道上皮损伤和肺功能水平，验证该通路在PAHs暴露致气道损伤中的作用，为PAHs损伤呼吸系统的机制提供新思路。

多环芳烃（PAHs）是常见的环境污染物之一。本课题组前期研究提示，PAHs可通过损伤气道上皮影响肺功能，但机制不清。组织修复异常是气道上皮损伤持续和多种肺部疾病发生的关键。既往研究发现Wnt5a介导的非经典Wnt-YAP/TAZ通路可通过抑制组织修复重要信号途径而影响修复功能，但该通路在PAHs暴露致气道上皮损伤和肺功能下降中的作用尚无报道。本项目通过细胞、动物实验结合人群研究较系统地探索了非经典Wnt-YAP/TAZ通路在PAHs暴露致气道损伤中的作用。选择PAHs代表物BaP进行不同剂量体内外染毒实验，测定不同时间点非经典Wnt-YAP/TAZ通路相关配体Wnt5a及关键因子表达水平，发现PAHs暴露与Wnt5a介导的非经典Wnt-YAP/TAZ通路关键因子之间的剂量-效应关系和时间-效应关系，了解了该途径在PAHs暴露致气道损伤和通气功能异常发生中的作用，明确了BaP染毒可通过激活Wnt5a介导的非经典Wnt-YAP/TAZ信号通路，诱发肺部炎症以及气道上皮损伤；进一步通过拮抗和补充Wnt5a的方法，探讨了该通路在PAHs暴露损伤气道上皮和通气功能中的作用，发现外源性加入Wnt5a可促进BaP暴露引起的炎症反应以及肺上皮损伤；采用拮抗Wnt5a能明显减轻以上作用，并有助于重构小气道和肺泡功能；通过测定已建立的队列人群个体PAHs暴露和非经典Wnt-YAP/TAZ通路关键指标的浓度，结合气道上皮损伤和肺功能水平，分析了非经典Wnt-YAP/TAZ通路关键因子与环境PAHs暴露、气道上皮损伤程度以及肺功能水平之间的关联，发现环境空气中PAHs与机体细胞增殖水平升高密切相关，且该效应主要来源于PM2.5上结合的4环及以上PAHs，同时验证Wnt5a介导的非经典Wnt-YAP/TAZ信号通路关键因子与肺功能水平，为PAHs损伤呼吸系统的机制提供新思路。本项目的顺利实施，不仅丰富了PAHs呼吸毒性的新分子机制，同时提示Wnt5a成为环境PAHs引起肺功能损伤干预靶点的可能。