气道内中性粒细胞胞外诱捕网的形成与清除——中性粒细胞哮喘机制新探索

Neutrophilic asthma, characterized predominately by neutrophil infiltration, is an independent respiratory airway inflammation phenotype of asthma. It has been shown that neutrophilic asthma is tightly correlated with clinical severe asthma, refractory asthma, steroid-resistant asthma, obesity asthma and etc. However, the mechanisms for this disease remain largely unknown. Neutrophil extracellular traps (NETs) are formed by neutrophils releasing their cellular contents in the form of DNA-protein complex, generating networks of extracellular fibers that are coated with anti-microbe histones and granule proteins (e.g. NE, MPO). NETs possess capacity to eliminate microorganisms, but are simultaneously immunogenicity and tissue toxicity. The proposed study capitalizes “neutrophilic respiratory inflammation”, linking neutrophilic asthma and NETs, and hypotheses that dysregulation of NETs formation and elimination in airway may play a key role in persistent airway inflammation and injury in neutrophilic asthma. Cross-section study and cohort study for neutrophilic asthma patients will be carried out and induced sputum test will be employed. The formation and characteristics of NETs will be observed, qualitatively and quantitatively analyzed, to delineate the correlation to disease status and the impact of medicine. In vitro, effects of NETs on neutrophils chemotaxis, and pulmonary macrophages on NETs clearance and influential factors will be investigated. All of these researches aim to provide new insights for pathogenesis research and therapy to this disease.

中性粒细胞哮喘是以中性粒细胞浸润为主的哮喘气道炎症表型，已发现与临床所见的重症哮喘、哮喘激素抵抗和肥胖型哮喘等关系密切，但目前对其机制知之甚少。中性粒细胞胞外诱捕网（NETs）是中性粒细胞胞内物质以DNA-蛋白质复合物形式释放出细胞外形成的被覆抗微生物组蛋白和颗粒蛋白（NE、MPO等）的解聚核染色质纤维网状结构，它既具有清除病原微生物的作用，又具有组织毒性和免疫原性。本课题以“中性粒细胞气道炎症”为切入点，提出NETs在气道内的形成与清除障碍可能是中性粒细胞哮喘气道炎症持续存在和气道损伤的关键环节。通过横断面调查与队列研究，采用诱导痰技术，观察中性粒细胞哮喘患者诱导痰中NETs的形成和特点，分析NETs的存在与疾病的相关性以及药物干预对NETs的影响，体外实验探讨NETs对呼吸道中性粒细胞的炎症趋化性，研究肺泡巨噬细胞清除NETs的情况，为中性粒细胞哮喘病理机制研究和治疗提供新思路。

中性粒细胞哮喘是以中性粒细胞浸润为主的哮喘气道炎症表型，已发现与临床所见的重症哮喘、哮喘激素抵抗和肥胖型哮喘等关系密切，但目前对其机制知之甚少。中性粒细胞胞外诱捕网（NETs）是中性粒细胞胞内物质以DNA-蛋白质复合物形式释放出细胞外形成的被覆抗微生物组蛋白和颗粒蛋白（NE、MPO等）的解聚核染色质纤维网状结构，它既具有清除病原微生物的作用，又具有组织毒性和免疫原性。本课题以“中性粒细胞气道炎症”为切入点，提出NETs在气道内的形成与清除障碍可能是中性粒细胞哮喘气道炎症持续存在和气道损伤的关键环节的假说。通过基础结合临床的研究模式，利用诱导痰、免疫荧光染色与共聚焦显微镜成像、ELISA等技术，发现：NETs存在于中性粒细胞哮喘患者诱导痰中，巨噬细胞具有通过破坏DNA网状结构清除NETs的作用。NETs的存在和疾病的状态（肺功能和哮喘控制水平）相关，药物的干预可以降低NETs的水平，为阐述中性粒细胞哮喘气道炎症与气道损伤提供科学证据。因此，本研究具有重要的科学意义及潜在应用价值，为哮喘评估及研发新的哮喘药物提供科学依据。