防哮方调控HIF1/2缺氧应激反应经TGF-β/Smad通路抑制哮喘气道重塑和炎症的作用及分子机制

Airway remodeling and inflammation are the most important pathological changes of chronic bronchial asthma. Traditional Chinese medicine (TCM) in one of the therapies of bronchial asthma. We have found that FangXiaoFang (FXF), a TCM anti-asthma prescription, had satisfactory effect on experimental asthma; however, the mechanisms are unknown. Because oxygen supply to airway tissues is reduced in asthma, hypoxia inducible factor-1 and -2 (HIF-1 and HIF-2) are upregulated, which thereby induce airway remodeling and inflammation. Our preliminary study have shown that HIF-1/HIF-2 was activated and transforming growth factor-1 (TGF-β1) was upregulated in the airway tissues of asthmatic rats and in the airway smooth muscle (ASM) cells and fibroblasts cultured under hypoxia. However, the signal transduction pathway mediating airway remodeling and inflammation has not yet been clarified. We hypothesize that FXF may modulate hypoxia-induced upregulation and activation of HIF-1 and HIF-2, then inhibit the TGF-β1-Smad2/3 pathway, and finally attenuate the airway remodeling and inflammation. Therefore, in this project, we plan to treat ASM cells and fibroblasts by FXF-containing serum as well as HIF1/2 gene interference; to detect the expression and/or activation of HIF-1/HIF-2, TGF-β1 and Smad2/3; to determine proliferation and transformation of ASM cells and fibroblasts, the synthesis and deposition of extracellular matrix molecules, and the production and release of cytokines. Moreover, the effects of FXF on signal molecules, airway remodeling and inflammation will be confirmed in asthmatic rats. Our project will clarify the molecular pharmacological mechanisms of FXF, which has larger novelty and clinical significance.

慢性哮喘最重要病变是气道重塑和炎症。中医药是治疗哮喘重要方法之一，我们发现防哮方有良好疗效，但机制不明。因哮喘时气道供氧不足引发缺氧，上调低氧诱导因子1/2（HIF1/2），进而诱导气道重塑与炎症变化。前期研究发现，在哮喘大鼠气道及低氧培养的气道平滑肌（ASM）和成纤维细胞中，HIF1/2激活、TGF-β1上调，但介导气道重塑和炎症的信号通路仍不清楚。我们假设防哮方可调控低氧状况下HIF1/2上调和活化，通过抑制TGF-β1-Smad2/3通路，减轻气道重塑与炎症变化。本项目拟用防哮方含药血清、HIF1/2基因干预等处理ASM和成纤维细胞，检测HIF1/2、TGF-β1、Smad2/3表达及活化，观察ASM和成纤维细胞增殖与转化、ECM合成与沉积、细胞因子合成释放；并在哮喘大鼠验证防哮方对信号分子、气道重塑和炎症的作用。研究将阐明防哮方分子药理机制，有较高创新性和临床意义。

哮喘是一种常见的阻塞性气道疾病，以炎症和气道重塑为特征，伴随肺功能的逐渐下降。中医药是治疗哮喘重要方法之一，防哮方是一种对哮喘患者有显著临床疗效的中药，但其作用机制尚未阐明。本研究旨在探讨FXF对大鼠哮喘模型气道炎症和重塑的抑制作用，并阐明FXF治疗哮喘中的作用机制与TGF-β/Smads信号通路相关。结果表明，FXF能减轻哮喘大鼠模型和ASM细胞的炎症细胞浸润，减少Th2细胞因子的产生，同时增加Th1细胞因子的表达。在哮喘大鼠中，FXF可减少过敏原引起的气道壁厚增加、杯状细胞增生和胶原沉积。在ASM细胞中，FXF抑制缺氧条件下诱导的细胞增殖和迁移。此外，缺氧时TGF-β和p-Smad3的表达明显增加，FXF治疗后可部分恢复，提示FXF通过恢复Th1/Th2细胞因子和TGF-β/Smad-3通路的平衡，减轻气道炎症和重塑，为哮喘患者提供了潜在的治疗途径。