香烟烟雾刺激下IL-27调控Th17/Th1免疫反应介导小鼠肺气肿发生的机制

Both Th17 and Th1 cells may play critical roles in the development and the pathogenesis of cigarette smoke-induced COPD. However, there is little information regarding the complexity of Th1 and Th17 cells and the mechanisms of their regulations in this context. Several reports suggest that IL-27 might have a relevant role in the lineage decision-making between Th17 and Th1 cells. In our previous studies, we found that the percentages of Th17, Th17/Th1 and Th1 cells in lungs of cigarette smoke (CS)-exposed mice were significantly increased compared to air-exposed mice, and the numbers of Th1 cells were much higher than the numbers of Th17 cells and Th17/ Th1 cells. Recently, We also found that the levels of IL-27, IL-17 and IFN-γ in the lungs of CS-exposed mice were much higher than those of air-exposed mice, and correlated with emphysematous lesions. Additionally, the levels of IL-27 positively correlated with the levels of IFN-γ. Base on these findings, we speculate that IL-27 are involved in the Th17/Th1 immune response in cigarette smoke-induced emphysema. In the present study, we will investigate the expression of IL-27, Th17 and Th1 cells in the lungs, peripheral blood and spleens of CS-exposed mice by flow cytometry, real-time PCR, double immunofluorescence staining and ELISA, explore the direct contribution of IL-27 in emphysema by treating with an IL-27 neutralizing protein, and assess the possible modulating effects of recombinant IL-27 (rIL-27) on Th17 and Th1 cells differentiations in vitro. Furthermore, we will investigate the capabilities of IL-27 to mediate the convertion between Th17 and Th1 cells in response to cigarette smoke by using adoptive transfer of Th17 cells or Th1 cells in scid mice. Identification of the immunomodulation mechanisms involved in the development of emphysema may have important implications for the development of new therapeutic methods to treat COPD.

Th17与Th1细胞在吸烟诱导COPD发病中起重要作用，但香烟刺激下两者的关系及调控机制尚不清楚。我们前期研究及相关文献报道显示，香烟烟雾暴露肺气肿小鼠肺内出现以Th1为主的Th1、Th17及Th17/Th1细胞上调；IL-27参与调控Th17、Th1分化及转化过程。预实验中我们发现香烟烟雾暴露肺气肿小鼠肺内IL-27、IFN-γ、IL-17水平明显增高，且IL-27与IFN-γ正相关。据此，我们推测，香烟烟雾刺激下IL-27通过调控Th1、Th17反应介导肺气肿发生。本项目拟采用细胞分子生物学实验方法，首先观察IL-27、Th17与Th1细胞在肺气肿小鼠肺组织、外周血、脾脏中的变化，继而研究IL-27对肺气肿发生的影响，通过体外培养、过继转让进一步探讨香烟刺激下IL-27对Th17、Th1细胞分化及相互转化的作用。以阐明香烟诱导肺气肿的免疫学发生机制，为早期防治COPD提供重要的思路。

Th1和Th17细胞在吸烟诱导的COPD/肺气肿发病中起重要作用，但香烟刺激下两者的关系及调控机制尚不清楚。本项目主要探讨香烟刺激下，IL-27对Th1和Th17细胞的分化、相互转化的影响及相关机制。结果显示：1、烟草刺激下，IL-27通过上调p-STAT1及转录因子t-bet促进Th1分化，通过下调p-STAT3及转录因子RORγt抑制Th17分化。2、烟草刺激下，T细胞转录因子t-bet与RORγt存在共表达，IL-27通过上调p-STAT1及转录因子t-bet促进小鼠Th17细胞向Th1方向转化。3、体内IL-27中和抗体干预小鼠后， 其Th1细胞分化减少，肺气肿程度有所减轻，证实IL-27通过促进Th1细胞分化放大炎症反应。本研究的完成进一步阐述了COPD炎症的特征及相关免疫调控机制，提示IL-27可能是今后COPD抗炎治疗的潜在靶点。