间质性肺病（ILD）是抗MDA5抗体阳性皮肌炎（DM）患者的重要临床特征，是影响预后的主要因素；但该抗体是否直接参与ILD发生发展尚不清楚。我们前期研究证实：(1) 抗MDA5抗体阳性的DM-ILD患者外周血中性粒细胞胞外诱捕网(NETs)生成水平显著升高; (2) 差异基因表达谱分析显示DM-ILD患者中性粒细胞中程序性坏死通路相关基因均高表达。本项目拟在细胞水平和动物模型中探讨：(1) 抗MDA5抗体直接诱发DM患者中性粒细胞形成NETs的状况，验证程序性坏死通路在此过程中的关键作用；(2) 研究DM中性粒细胞诱发的NETs对肺成纤维细胞功能的影响；(3)利用肌炎模型小鼠及基因敲除鼠，通过过继免疫及干预治疗实验，证实抗MDA5抗体在DM-ILD的致病作用。本研究有望明确抗MDA5抗体在DM中的致病作用，阐明其诱发中性粒细胞NETs形成参与DM-ILD发病的分子机制。

Interstitial lung disease(ILD) is an important clinical feature of anti-MDA5 antibody-positive dermatomyositis (DM) patients and a major prognostic factor. However, whether the antibody is directly involved in the occurrence and development of ILD remains unclear. In previous study, we found significantly up-regulated expression of neutrophils extracellular traps(NETs) in anti-MDA5 antibody-positive DM patients. Additionally, necroptosis associated genes were found to be highly expressed in DM-ILD neutrophils by microarray analyses. In the present proposal, we will address the following issues at cellular and animal model leves: (1) Whether anti-MDA5 antibody can directly induce the formation of NETs in neutrophils of DM patients, and verifying the key role of necroptosis in this process; (2) Study the effect of NETS induced by neutrophils of DM patients on the function of pulmonary fibroblasts; (3) Design adoptive immunity and intervention therapy experiments using myositis mice and a series of gene knockout mice to confirm the pathogenicity of anti-MDA5 antibody in DM-ILD. Our study will probably clarify the pathogenic role of anti-MDA5 antibody in DM, elucidate the molecular mechanism of anti-MDA5 antibody involved in the pathogenesis of DM-ILD by inducing NETs formation of neutrophils.