IL-17A在成纤维细胞来源CXCL12介导的COPD气道重塑中的作用及机制研究

The interactions of fibroblasts and bronchial epithelial cells play key roles in the progression of airway remodeling in chronic obstructive pulmonary disease (COPD). IL-17A triggers the activation of fibroblasts and secretion of numerous inflammatory mediators, and then participate the epithelial-to-mesenchymal transition (EMT) process. We found that higher levels of CXCL12 mRNA and protein in the mice primary lung fibroblasts culture with IL-17A treatment and decreased expression of CXCL12 in lung tissues of mice with anti-IL-17A antibody treatment compared with the control mice in the preliminary study. There were researches showed that CXCL12/CXCR4 pathway is involved in the development of airway chronic inflammation, so we hypothesis that IL-17A is involved in the airway remodeling of COPD by inducing the activation of fibroblasts and driving the EMT process, which are depending on the CXCL12/CXCR4 pathway. In vitro, the primary lung fibroblasts were treated with IL-17A and the activation of fibroblasts and the expression of CXCL12 were analyzed. The EMT process were studied in the bronchial epithelial cells co-cultured with the conditioned medium (CM) of primary lung fibroblasts from COPD patients. In vivo, based on the mice model of COPD induced by CS exposure, we evaluate the effect of anti-IL-17A antibody and AMD3100, the CXCL12/CXCR4 pathway inhibitor, on the inhibition of lung fibroblasts, EMT, the improvement of airway remodeling and the potential signal transduction mechanism. This project presented an innovative theory that IL-17A can promote the airway remodeling in COPD by activating the fibroblasts/CXCL12/CXCR4 pathway, which provided a novel target for intervention of airway remodeling in COPD.

成纤维细胞和支气管上皮细胞的相互作用在COPD的气道重塑中发挥重要作用，IL-17A可刺激成纤维细胞活化并分泌炎性介质，促进支气管上皮间充质转化（EMT）。我们的前期研究发现，IL-17A促进成纤维细胞分泌CXCL12增加，IL-17A抗体则降低小鼠肺组织CXCL12的表达，而CXCL12/CXCR4通路参与了多种慢性气道炎症的发展。因此假设：IL-17A刺激肺成纤维细胞活化后参与COPD气道重塑的过程可能依赖于CXCL12/CXCR4通路。本项目拟采用IL-17A刺激培养，分析成纤维细胞活化、CXCL12表达变化及对EMT的影响；体内研究IL-17A抗体和CXCL12抑制剂对小鼠COPD模型肺组织成纤维细胞活化、EMT和气道重塑的作用及可能信号机制。本项目提出了IL-17A通过成纤维细胞/CXCL12/CXCR4通路参与COPD气道重塑的新见解，为改善COPD气道重塑提供新的干预靶点。

本项目旨在通过体外及体内实验，研究IL-17A对肺成纤维细胞活化的影响，并通过CXCL12/CXCR4通路促进EMT进而介导COPD气道重塑过程。本课题组研究发现IL-17A可以活化小鼠及人原代肺成纤维细胞，并分泌CXCL12。将IL-17A刺激后的人原代肺成纤维细胞培养上清与人肺上皮细胞16HBE共培养，发现上皮细胞出现EMT，与ERK通路的激活相关。在体内实验部分，本课题组通过建立小鼠COPD模型，发现COPD小鼠肺组织发生气道重塑，而抗IL-17A抗体和CXCL12/CXCR4通路阻滞剂AMD3100的使用通过抑制EMT改善了气道重塑，该过程与ERK信号通路相关。本研究结果是对COPD疾病发生发展机制的补充，也为COPD的治疗提出了新思路。