气道平滑肌生物力学行为异常与哮喘病理机制关系的研究

Asthma is a major chronic repiraotry disease, yet its etheiology is still unclear. Considering that the airway smooth muscle (ASM) is the end-effector of bronchial airway narrowing that ultimately obstructs pulmonary airflow in ashtmatic patient, we thus propose to take a multi-method and multi-level approach to study alterations of biomechanical behaviors in either normal or asthmatic state, and their implications to astham pathobiology. The specific aims include: 1) To explore the relationship between air pollutants such as PM2.5 and the abnormalities of ASM biomechanical behaviors. 2) To reveal the abnormalities of biomechanical behaviors of ASM cells, expecially those in response to extracellular microenvironment factors (substrate stiffness, stretch and inflammatory factors) and the associated regulatory mechanicams. 3) To elucidate those abnormalities and their roles in airway excessive narrowing with the view point of soft matter rheology such as fluid-solid state transition. 4) To establish a multi-layered mechanical model of the airway wall that is embeded with biomechanical features of ASM, and real-patient based three dimensional models of pulmonary airways for simulation of the airway narrowing process. This proposal is raised to overcome the limitations of studying ASM mechanics at separate and singular level in normal state, thus may enable a more comprehensive and accurate understanding how ASM biomechanical behaviors at different levels participate and mediate the regulation of the multi-layered airway narrowing, as well as their roles in the excessive narrowing of asthmatic airways, and provide insights in seeking new approaches for diagnosis and therapy of asthma based on targeting ASM.

哮喘是一种重大慢性呼吸道疾病，但其病理机制尚无定论。鉴于气道平滑肌是哮喘气道过度缩窄导致呼吸障碍的主要效应器，本项目拟从细胞到器官多层次研究正常和病理状态下气道平滑肌生物力学行为的变化及其与哮喘病理机制的关系，包括：1）探究PM2.5等大气污染物与气道平滑肌生物力学行为异常的关系；2）揭示气道平滑肌细胞生物力学行为异常，特别是其对胞外微环境因素（基质硬度、拉伸刺激和炎症因子）响应的异常及调控机制；3）运用流-固转化等软物质流变学观点解释细胞力学行为异常及其在气道过度缩窄中的作用；4）建立嵌入气道平滑肌的多层气管力学模型和真实气道三维数值模型并数值模拟气道的收缩过程。本项目旨在克服单一层次研究的局限性，系统深入地研究气道平滑肌在不同层次的生物力学行为并揭示其如何参与和介导多层结构气道的收缩功能，为全面解释哮喘气道过度缩窄的病理机制和探索以气道平滑肌为靶点的诊治手段提供科学依据和新的思路。

哮喘是一种重大慢性呼吸道疾病，全球患者超3亿人，但其病理机制并不清楚，至今尚无治愈疗法。气道平滑肌细胞（ASMCs）参与哮喘所有病理过程并且是气道狭窄的终极力学因素。因此，ASMCs的生物力学特性与哮喘病理因素的相互关系是哮喘病理机制中的一个关键科学问题。本项目围绕这一问题，从分子与细胞机制、药物开发与研究方法等方面系统性地开展了以下研究。.1. 在分子与细胞机制方面.1）阐明了哮喘易感基因（ADAM8、ADAM33）作为哮喘治疗新靶点的作用机制；.2）揭示了ASMCs通过胞外基质传递的牵张力建立远程信号交流的机制，为深入认识生理病理条件下气道组织重构现象和机制提供了新的角度；.3）建立了模拟气道凹/凸曲面微环境的新方法，发现了ASMCs在不同曲率凹/凸曲面上表现出不同生物力学行为的现象及其调控机制；.4）阐明了臭氧等环境污染物通过外泌体等调节ASMCs生物力学行为，进而参与哮喘病理机制的途径；.5）建立了嵌入气道平滑肌层的气道组织力学数值模型，获得了气道组织中应力分布不均及其与肌层厚度和刚度的关系。.2..在药物发现/器械开发方面.1）揭示了传统哮喘治疗中药通过活化苦味受体从而舒张ASMCs的机制和基于中药苦味物质的气道舒张剂筛选和发现策略；.2）发现了跨膜蛋白16A在炎症因子作用下引起ASMCs的膜去极化及气道高反应性的作用；.3）揭示了传统针刺疗法刺激产生金属硫蛋白2与ASMCs表面肌动蛋白结合蛋白2结合以舒张ASMCs的作用机制；.4）构建了具有不同层间距的多层结构胶原基底材料和结构稳定且具备抗菌与自愈合功能的表面涂层材料，为气道组织工程材料研发提供了新思路。.3..在方法学方面.1）建立了FRET探针和影像实验技术体系，并发现血小板生长因子活化ASMCs胞内Fyn的现象；.2）构建了一套细胞富集分选芯片系统，并在低丰度循环肿瘤细胞分型检测中得到验证。.本项目的完成对深入认识哮喘病理过程中ASMCs的作用与机制，进而彻底揭示哮喘的发病机制具有重要参考价值，并为探索哮喘等呼吸疾病预防和诊治的新疗法和新技术提供了新的思路和有价值的参考方案。