气道上皮细胞-肺部固有淋巴细胞对话在不同表型支气管哮喘中的作用和机制研究

Group 2 innate lymphoid cells (ILC2) play essential roles in the initiation of eosinophilic asthma which is featured by airway eosinophilic inflammation. However, the role of ILCs in neutrophilic asthma which is irresponsive to inhaled corticosteroid remains unknown. IL-12 and IL-25 promote the differentiation and activation of ILC1 and ILC2, respectively. We found that epithelial IL-25 expression was increased in subjects with eosinophilic asthma, whereas epithelial IL-12 expression was increased in subjects with neutrophilic asthma. Meanwhile, the expressions of the markers for ILC1, IL12Rβ2 and T-bet, were markedly increased in BALF cells from subjects with neutrophilic asthma. And the levels of effector molecule of ILC1, IFN-γ, was increased in BALF from subjects with neutrophilic asthma. Importantly, epithelial IL-12 levels were significantly correlated with BALF IFN-γ levels and IL12Rβ2, T-bet expression levels in BALF cells. Therefore, we hypothesize that epithelial cytokine including IL-12 promotes ILC1 differentiation and activation which contribute to airway neutrophilic inflammation in neutrophilic asthma. We propose to examine the main subgroups of ILCs in neutrophilic asthma, and determine the role of ILC1 cells in the pathogenesis of neutrophilic asthma. We are going to investigate the molecular mechanisms underlying airway epithelial cell-ILCs crosstalk. This project will provide new target for the treatment of neutrophilic asthma which is irresponsive to corticosteroid therapy.

肺部2型固有淋巴细胞（ILC2）在嗜酸性粒细胞哮喘中有重要作用，但ILC细胞在对激素不敏感的嗜中性粒细胞哮喘中的作用不清楚。IL-12、IL-25分别促进ILC1和ILC2细胞活化，我们发现嗜酸性粒细胞哮喘患者气道上皮细胞（EC）IL-25表达增高，而嗜中性粒细胞哮喘EC中IL-12表达明显增高，并且ILC1细胞的分子标记IL12Rβ2、T-bet和效应分子IFN-γ在嗜中性粒细胞哮喘患者中表达明显上升、而且与EC细胞IL-12水平有显著相关性，我们推测气道EC通过表达IL-12等促进ILC1细胞分化，EC-ILC1细胞对话在嗜中性粒细胞哮喘发病中有重要作用。我们拟分析不同表型哮喘患者肺组织ILC亚群的分布，研究ILC1在嗜中性粒细胞哮喘中的作用，探索气道EC—肺部ILC对话的分子机制，从EC—ILC细胞对话的角度为支气管哮喘，特别是为激素不敏感的嗜中性粒细胞哮喘的治疗提供新思路。

气道上皮细胞-肺部固有淋巴细胞对话在哮喘发病中有重要作用，比如气道上皮细胞通过表达IL-25，促进2型固有淋巴细胞（ILC2）的分化，在嗜酸性粒细胞哮喘或者type 2-high哮喘发病中有关键作用。我们通过实施本项目发现，type 2-high哮喘（嗜酸性粒细胞哮喘）、type 2-low哮喘（包括嗜中性粒细胞哮喘）气道上皮细胞miRNA表达谱存在显著差异。miR-206在type 2-high哮喘中的表达明显高于type 2-low哮喘，并证实ATP水解酶CD39是miR-206靶基因。过敏原诱导上皮细胞释放ATP，能够反馈性下调miR-206和上调CD39表达。同时，细胞外ATP介导了过敏原诱导的气道上皮细胞IL-25, TSLP表达。因此，miR-206通过CD39-ATP轴调节气道上皮细胞IL-25和TSLP表达。抑制气道上皮细胞miR-206的表达，通过CD39-ATP轴下调IL-25和TSLP的表达，抑制2型肺部固有淋巴细胞增殖，减轻哮喘气道炎症、粘液过度分泌和气道高反应性。因此，气道上皮细胞miR-206通过CD39-ATP轴调节IL-25表达以及肺部ILC2细胞的增殖。我们的研究发现了调节气道上皮细胞和肺部固有淋巴细胞对话的新的上游机制。我们还发现IL-25通过阻断NF-kB核转位，抑制嗜中性粒细胞哮喘肺部巨噬细胞IL-12、IL-23表达和M1极化，从而减轻嗜中性粒细胞哮喘气道炎症。这为激素不敏感的嗜中性粒细胞哮喘的治疗提供了新思路。