吸烟诱导人气道上皮细胞纤毛变短及纤毛相关基因表达水平改变在COPD发病机制中的作用

Cigarette smoking is the major risk factor of COPD. The reduction of mucociliary clearance which is partly maintained by the length of the cilia of the airway epithelial cells is the important pathophysiological change of COPD. Although the previous research has already demonstrated the shorten-length cilia of in vivo large airway epithelial cells which is associated with the down regulation of six cilia related protein coding genes, whether the shorten length cilia as well as the basic molecular regulative mechanism can be founded in smoking COPD patients is still unknown. The present study will try to find the difference of the cilia length and above mentioned six cilia related genes' expression level of the biopsy and brush airway epithelial cells among the groups of health non-smoker, health smoker and smoking COPD patients; to establish the in vitro model of cultured airway epithelial cells with cigarette induced shorten length cilia and observe the pathological characteristics in this progress as well as the involved genetic expression level changes; to express down-regulated cilia related genes ectogenically in cultured airway epithelial cells from health smoker and smoking COPD patients via infected by lentivirus vectors encoding the target genes and then observe whether the shorten of cilia length is reversible. In conclusion, this research is to demonstrate that the cigarette induced shorten length cilia is one of the principal pathogenesis of COPD.

吸烟是COPD的主要危险因素。粘液-纤毛转运系统功能障碍是COPD的重要病理生理改变之一。气道上皮细胞纤毛的长度是维持其正常功能的基础。研究表明健康吸烟者的纤毛长度变短，六个与纤毛形成和结构相关的蛋白质编码基因在健康吸烟人群中基因表达水平有所下调且与纤毛变短存在相关性，但吸烟所致COPD患者的纤毛长度是否发生相同改变及其分子生物学调控机制尚不清楚。该研究拟通过：1.比较健康非吸烟者、健康吸烟者、吸烟COPD患者活检及刷片大气道上皮细胞纤毛长度和6个相关基因表达水平的不同；2.构建吸烟诱导健康上皮细胞纤毛变短的体外培养模型观察其纤毛变短现象以及参与调控基因表达水平的变化；3.构建慢病毒载体感染体外培养的健康吸烟者和吸烟COPD患者气道上皮细胞，外源性地表达前期试验中表达水平下调的纤毛相关基因，观察其纤毛长度变短是否可逆；证实吸烟诱导气道上皮细胞纤毛变短是COPD发病机制的重要环节之一

有研究表明，吸烟会使气道上皮纤毛变短，同时伴随着一些纤毛结构和功能相关基因表达的下调。纤毛结构及功能障碍是吸烟相关疾病尤其是COPD的重要病理生理改变之一。本研究最终通过（1）比较健康非吸烟者、健康吸烟者刷片气道上皮细胞纤毛长度和6个纤毛相关基因表达水平的不同；（2）成功构建吸烟诱导健康气道上皮细胞纤毛变短的体外培养模型观察其纤毛变短现象以及参与调控基因表达水平的变化；（3）慢病毒载体感染体外培养的、香烟烟雾提取物（CSE）处理的气道上皮细胞，外源性地表达前期试验中表达水平被CSE下调的纤毛相关基因，观察其是否可防止纤毛长度变短；发现无论在体内外，吸烟均可缩短纤毛长度，并抑制纤毛发育、结构和功能相关基因的表达；体外模型中，通过慢病毒持续过表达被吸烟下调的纤毛相关基因后，可有效防止吸烟引起的纤毛变短。研究结果提示：（1）吸烟可能通过下调纤毛发育、结构等基因的表达，抑制纤毛长度，而这一机制可能是吸烟导致相关疾病，特别是COPD的发病机制之一；（2）气道上皮细胞体外分化培养模型的建立及体内发现的再现，为进一步研究吸烟引起的相关疾病（主要是COPD）的发病机制及寻找可能的干预靶点提供了良好的研究工具；（3）在体外实验中，慢病毒介导纤毛相关基因DNAH5在气道上皮细胞的持续过表达，可以部分缓解吸烟引起的纤毛变短效应，这一发现为干预吸烟相关疾病COPD的发生发展提供了新的策略。