内质网应激CHOP信号通路通过影响巨噬细胞固有免疫应答参与哮喘发病机制探讨

Several recent studies have revealed that endoplasmic reticulum stress (ERS) is implicated in the pathogenesis of asthma. C/EBP homologous protein (CHOP), also called GADD153 or DDit-3, plays an important role in the progress of ERS. However, to our knowledge, there were no reports about the effects of CHOP on asthma. Meanwhile，we completed some reseaches and found that ERS involved of CHOP signal pathway in asthma mainly happened in macrophages by comparing the CHOP gene knockout C57BL/6 mice asthmatic models to the wild-type mice asthmatic models. Based on these knowledge，firstly, we plan to investigate the effects of ERS on macrophages' fate (polarization, apoptosis and necropotosis) by detecting the induced sputum from asthma patients in this study. Thus, some upstream and downstream moleculars, which have relationship with CHOP, would be selected for next investigation. Secondly, some interfering studies will be carried out in vivo and in vitro on the CHOP gene knock-off mice，in order to reveal the role of CHOP signal pathway in macrophages and the effcts on airway inflammation. The results of the study will reveal the detail of the CHOP signal pathway and the effects of it on asthmatic airway inflammation. This study may augment the knowledge of asthma pathogenesis and potentially help to find a new promising target of asthma therapy. Thus, it have important value of science.

目前研究表明，内质网应激促进了支气管哮喘的气道炎症。CHOP蛋白（亦称GADD153或DDit-3）是内质网应激过程中的重要信号分子，其在哮喘中具体作用机制尚无研究。在我们已经进行的预实验中，通过对比分别用CHOP基因敲除小鼠和野生型小鼠制作的哮喘模型，发现CHOP蛋白关联的内质网应激主要发生在哮喘巨噬细胞中。基于以上基础，本研究拟通过观察哮喘患者诱导痰的巨噬细胞中内质网应激对巨噬细胞的影响（极化方向、凋亡及程序性死亡），分析探讨哮喘巨噬细胞中CHOP信号的上游影响因素及下游信号传导；并进一步以CHOP基因敲除小鼠为研究工具，通过动物模型和细胞体外干预实验，阐明不同炎症环境下，CHOP信号通路对哮喘巨噬细胞的影响特征及其具体分子机制。本研究的实施将进一步扩展我们对于哮喘发病机制的认识，并可能发现新的潜在治疗靶点，具有重要的科学意义和理论价值。

研究发现内质网应激参与哮喘的发病，本研究以内质网应激为切入点，深入的阐释内质网应激标志Chop在哮喘发病中的作用及作用机制。研究发现在哮喘患者和小鼠过敏性哮喘模型中存在异常的Chop表达以及内质网应激。Chop主要在巨噬细胞中过表达。在OVA诱导的哮喘模型中，敲除Chop小鼠的气道炎症，气道重塑和气道高反应性较对照小鼠明显减轻。体外实验进一步发现Chop的高表达能促进巨噬细胞的替代活化。机制研究中首次发现了IL-4 /STAT6 /转录因子EC（Tfec）/ IL-4受体α正反馈调节通路，其中IL-4诱导Chop表达，然后促进STAT6的磷酸化，磷酸化的STAT6增加Tfec表达，而Tfec转录IL-4受体α表达以促进巨噬细胞替代活化，进而参与到哮喘的发病机制。通过慢病毒降低Chop的表达能有效治疗OVA诱导的小鼠哮喘模型。进一步的研究发现哮喘患者诱导痰中CHOP+CD206+巨噬细胞的数目与肺功能中FEV1和FEV1/FVC%呈现显著负相关。本研究发现了内质网应激及Chop通过调控巨噬细胞的替代活化参与哮喘的发病机制，并为哮喘的治疗提出了新的标靶。