基于Jagged/Notch信号通路调控小气道与肺泡上皮异常分化的补肺益肾方治疗COPD的作用机制研究

Chronic obstructive pulmonary disease(COPD) is a kind of serious diseases. BuFeiYiShen prescription has good effect on COPD, involving in complex mechanisms. Anti-inflammatory effects of BuFeiYiShen prescription might be related to JAK / STAT or NF-κB signaling pathways in previous study. However, these mechanisms can not explain some effects such as improving pulmonary ventilation, regulating distribution or amounts of T lymphocyte subsets in blood and bronchoalveolar lavage fluid. The results show that there are probably other mechanisms underlying these effects. Key pathology of COPD includes of abnormal differentiation of small airway epithelium and airway remodeling, composing of mucus secretion, airway remodeling and alveolar epithelial- mesenchymal transition, et al, which are related to Jagged/Notch signaling pathway. Thus, we speculate that therapeutic effect on COPD of BuFeiYiShen prescription may be interfering with Jagged/Notch signaling pathway. To confirm the hypothesis, a new study program is given to explore whether regulation of Jagged/Notch signaling pathway is one of mechanisms on abnormal differentiation of small airway epithelium and alveolar epithelialium for BuFeiYiShen prescription by in vivo and in vitro methods, such as COPD rat model made by cigarette smoke extract, cell model attacked with cigarette smoke and LPS, indexes assays of molecular biology and immunology, and so on. In a word, based on reseach of overall level, cell level and molecular level, the purpose of the study is to explore the relationship between Jagged/Notch signaling pathway and some efficacy for BuFeiYiShen prescription against COPD.

慢性阻塞性肺疾病(COPD)是严重危害人类健康的疾病，补肺益肾方对其有较好疗效，涉及复杂的作用机制。前期研究发现其抗炎等作用可能与JAK/STAT、NF-κB信号转导路径有关，但不能解释补肺益肾方改善通气、调节T淋巴细胞亚群数量等作用，说明尚存在其他的作用机制。肺小气道上皮的异常分化以及气道重构是COPD关键的病理环节，Jagged/Notch信号通路参与黏液分泌、气道重塑、肺泡上皮间质化等多个病理环节的调控，由此我们推测补肺益肾方可能通过干预Jagged/Notch信号通路对COPD产生治疗作用。因此，我们应用COPD大鼠模型和香烟烟雾提取物与脂多糖联合攻击的细胞模型，采用分子生物学以及免疫学等技术，研究Jagged/Notch信号转导通路相关因子对COPD小气道上皮和肺泡上皮异常分化的调控，从整体-细胞-分子层面，阐释补肺益肾方基于Jagged/Notch信号通路的作用机制和疗效。

补肺益肾法是中医治疗COPD的常规方法，得到中医学界的认可，但其临床治疗的机制尚未明确。本研究建立COPD大鼠模型，评估肺功能、肺组织病理、炎症因子等变化，确认补肺益肾方的抑制COPD效应，发现干预后，Notch通路中Dll4、Hes1、Hey1、Notch1、Hey2、Heyl、Jag1、Notch3、Dll1、Notch4的mRNA表达降低。进一步的研究发现：补肺益肾方体外抑制香烟烟雾诱导的肺泡上皮细胞的间质转化和气道上皮细胞的MUC5AC蛋白的高分泌；未发现间质转化的肺泡上皮细胞Notch信号通路的活化，但补肺益肾方作用的烟雾诱导的细胞，Notch信号通路进一步抑制；高分泌MUC5AC的气道上皮细胞存在Notch信号通路的活化，补肺益肾方抑制Notch信号通路的活化，支持课题立项的假说：补肺益肾方调控气道上皮异常分化与其对Notch信号转导的干预有关。进一步的研究揭示出涉及的靶点信号分子有：Notch3、Notch4、Jagged1、Delta3、Delta4和HEY1。研究还探讨了补肺益肾方与Notch抑制剂DAPT之间的相互作用。得出的结果如下：两者抑制烟雾诱导的肺泡上皮间质转化，合用存在减效关系；两者抑制烟雾诱导的肺气道上皮细胞的MUC5AC高分泌，合用存在增效关系。上述研究结果，初步揭示了补肺益肾方抑制COPD的作用与Notch信号通路的抑制有关，为进一步的机制探讨提供了依据和参考。