HMGB1-NETs信号促发化疗所致肺纤维化及obculactone干预纤维化进程的分子机制研究

Pulmonary fibrosis induced by chemotherapy is characterized by crypticity, unreversibility and lethality. Therefore, elucidation of key molecular events at the initial stage of pulmonary fibrosis is essential to identify the therapeutic targets. We have found that (1) Neutrophil extracellular traps (NETs) appeared in the pulmonary microvessels before tissue lesions been observed, and demonstrated a correlation with the occurrence and development of pulmonary fibrosis; (2) the neutrophils were activated by one of the alarmins, HMGB1, which was released from lung epithelial cells; (3) obaculactone, a small compound, can selectively affect lung epithelial cells, inhibit HMGB1 production and improve bleomycin induced pulmonary fibrosis in mice. The present study is to investigate the following problems: (1) what molecular mechanism is underlying the release of HMGB1 from the alveolar epithelial cells after chemotherapy as well as how, when and where does HMGB1 induce the activation and release of NETs? (2) What is the mechanism underlying the effects of obaculactone on HMGB1 release and NETs formation? This study aims to clarify the molecular mechanism in the early process of pulmonary fibrosis and to provide a new target and a potential drug candidate for clinical treatment.

化疗诱发的肺纤维化具有隐蔽性、难逆性和致死性。阐明疾病发生初始阶段的关键分子事件才能有助于发现治疗靶标。我们发现，(1)中性粒细胞胞外捕捉网（NETs）与肺纤维化的发生与发展呈现良好的相关性。(2)NETs释放可能是源于肺上皮细胞释放的预警素HMGB1。(3)化合物obaculactone能够选择性地影响肺上皮细胞，抑制HMGB1生成，改善博来霉素诱导的小鼠肺纤维化。本研究希望阐明两个问题：(1)化疗药物刺激肺泡上皮细胞释放预警素HMGB1的分子机制及HMGB1在时间、浓度、发生部位方面如何诱导中心粒细胞活化并释放NETs。(2)化合物obaculactone通过什么机制平息HMGB1的释放并抑制NETs的生成。本课题希望以obaculactone为小分子探针，阐明化疗过程中肺组织纤维化病变早期的分子事件，为临床治疗提供新的干预靶标和候选药物。

化疗诱发的肺纤维化具有隐蔽性、难逆性和致死性。阐明疾病发生初始阶段的关键分子事件才能有助于发现治疗靶标。本课题首先是发现了肺纤维化过程中预警素HMGB1的新生物学功能，阐明了HMGB1被肺上皮细胞分泌，刺激中性粒细胞胞外捕捉网NETs产生，以及NETs的下游信号和被巨噬细胞内化的过程。在这一现象的基础上，通过运用体内、体外模型，发现HMGB1的抑制可抑制肺上皮的损伤，促进紧密连接的表达和重排，抑制中性粒细胞的浸润以及炎症，并由此改善肺纤维化的症状。其次，本课题阐明了obaculactone治疗肺纤维化的作用及机制。我们首次发现了obaculactone对HMGB1分泌，中性粒细胞迁移和浸润，NETs产生，以及其后的巨噬细胞介导的炎症反应具有抑制作用，对巨噬细胞活化过程中的TLR4-NF-kB和NLRP3通路都有抑制作用。最后，本研究发现了AMPK信号，MSK信号与HMGB1-TLR4-NETs之间的相互作用，以及与相关疾病之间的高度相关性，尝试通过调控AMPK来重建炎症与修复之间的平衡，据此奠定了围绕这条分子通路干预炎症性疾病的基础。本课题以obaculactone为小分子探针，阐明化疗过程中肺组织纤维化病变早期的分子事件，为临床治疗提供新的干预靶标和候选药物。本项目顺利完成研究计划，已发表SCI论文5篇，尚待发表2-3篇。项目运行期间新申请专利2个，获授权专利2个。培养多名研究生毕业。获教育部自然科学奖一等奖。