气道上皮细胞中脂伐/钙振荡的变化导致哮喘急性发作的初步研究

Acute exacerbation of asthma seriously affects the life quality of patients and is life-threatening. Increased inflammatory response of the airway epithelial cells plays a pivotal role in the acute exacerbation of asthma. Therefore, exploring the triggering mechanism of the increased inflammatory response of airway epithelial cells is supposed to provide new target for preventing acute exacerbation. Our previous work showed that asthmatic Th2 cytokine IL-4 could change the frequency of intracellular calcium oscillation, which maybe resulted from lipid rafts clustering and integrating the calcium signal pathway on the epithelial cells membrane,therefore regulate the expression of the downstream genes, which contribute to "triggering factors induced increased inflammatory response of the airway epithelial cells". We hypothesized that "trigger factors could induce lipid rafts clustering in airway epithelial cells, therefore regulate the calcium oscillation by integrating calcium signals and increase the inflammatory response of the airway epithelial cells to stimuli, which lead to acute exacerbation of asthma".The aim of this project is to verify our hypothisis at molecular, cell and animal levels.The results could contribute to clarify the triggering mechanism of asthma and provide new target for preventing acute exacerbation of asthma.

哮喘的急性发作严重影响患者的生活质量并威胁生命。气道上皮细胞的炎症反应性增高在哮喘的急性发作中起着至关重要的作用，因此探讨"诱发因素导致气道上皮细胞炎症反应性增高"的发生机制可为预防哮喘急性发作提供靶点。申请者的预实验提示，哮喘细胞因子IL-4可通过上皮细胞膜上的脂筏对钙信号整合后改变钙振荡的频率；而钙振荡频率的改变又可调控下游的转录因子。这可能是参与"诱发因素导致气道上皮细胞炎症反应性增高"的机制。本项目拟从分子、细胞及动物整体水平展开研究，以验证"哮喘的诱发因素影响气道上皮细胞脂筏的聚集，从而整合细胞的钙信号而影响钙振荡的频率，进而引起气道上皮细胞对刺激的反应性增高，导致哮喘急性发作"的创新性假说，研究结果将有助于阐明哮喘的触发机制并可为预防哮喘急性发作提供新的靶点。

哮喘的急性发作严重影响了患者的生活质量并威胁生命安全。气道上皮细胞的炎症反应性增高在哮喘的急性发病中起着重要作用。粘液分泌的增加能促进气道的高反应性，是哮喘的一项重要特征。本项目从分子、细胞和动物模型多个水平研究了哮喘相关细胞因子IL-4、IL-5、IL-13，诱发因素病毒感染、冷空气刺激对支气管上皮细胞脂筏形成，细胞钙振荡和粘液分泌的影响。哮喘动物模型用脂筏抑制剂干预后，观察病毒感染、运动、冷空气等对哮喘急性发作的影响。本研究首次发现在大鼠上皮气道细胞内，IL-4 促进caveolin-1蛋白在脂筏内的聚集以及TPRC1 蛋白在脂筏上的共定位，破坏脂筏的结构和阻断TPRC1 蛋白能削弱IL-4介导的钙信号，及下游NF-κB活性的增强和MUS5AC的合成增加。IL-4通过诱导脂筏的聚集并激活TPRC1 蛋白来增强MUS5AC的合成。因此，IL-4通过促进富含caveolin-1蛋白脂筏的聚集并活化脂筏内的TPRC1 蛋白，进而增强钙信号和上调NF-κB的活性，最终导致MUS5AC合成的增加。本研究发现了哮喘细胞因子致粘液合成增加的新的信号机制，结果将有助于阐明哮喘的触发机制并可为预防哮喘急性发作提供新的策略。