TAM/Gas6在石英粉尘致炎性反应及纤维化中的作用及机制

Pneumoconiosis cause by inhaling quartz (crystalline silica) is the most serious occupational disease in China. The activation and inhibition of innate immune is the source of the inflammatory reaction and fibrosis induced by quartz. However, there is no enough research on this topic. In this project, we plan to evaluate the role and mechanism of TAM (Tyro3、Ax1、Mer）/Gas6, one for innate immune suppression, in the processes of inflammation and fibrosis caused by quartz. We will expose pure quarts to macrophage and mouse in the experiments. The levels of Toll-like receptor, TAM/Gas6, subsequent cytokine follow-up, and inflammation cytokines such as IFN, NF-κB, TNF-α will be determined after quartz exposure to macrophages. The dose or time response relationship between quartz and TAM/Gas6 will be evaluated. After that, the role of activating TAM or adding Gas6 on suppressing immune inflammatory caused by quartz will be discussed. After intratracheal instillation of quartz, the changes of inflammation and fibrosis in different periods will be observed in normal mouse and mouse with anti-TAM/Gas6. More attention will be paid on the effects of activating TAM and/or adding Gas6 to mouse just before they are exposed to quartz. Then, we will compare conditions of inflammation and fibrosis among no-quartz exposed workers, quartz exposed workers and silicosis cases using molecular epidemiological methods. We will evaluate the relationship between the ability to activate TAM/Gas6 and incidence of silicosis. This research project will provide new insight for mechanism research of health damage cause by quartz and provide new idea for the prevention and treatment of pneumoconiosis.

石英粉尘所致尘肺是我国最严重职业病，先天免疫激活与抑制在石英致炎性反应和纤维化的源头，但研究不足。本项目拟研究先天免疫抑制TAM(Tyro3、Ax1、Mer）/Gas6路径对石英所致炎性及纤维化的作用及调控机制。开展巨噬细胞和小鼠的石英染尘实验，测定石英与巨噬细胞培养后Toll受体、TAM/Gas6及后续因子变化，及炎性因子IFN、NF-κB、TNF-α等水平，明确石英与TAM/Gas6的剂量和时间-效应关系，探讨激活TMA受体和补充外源性Gas6对抑制免疫炎性反应的作用；通过动物实验比较拮抗TAM/Gas6后，不同时间点肺部免疫炎性反应和纤维化改变，探讨激活TAM和补充Gas6对炎性和纤维化的抑制作用；采用分子流行病学方法，比较非接尘、石英接尘和矽肺患者炎性及肺纤维化情况，分析TAM/Gas6激活能力和水平与矽肺发病的关联，为石英粉尘健康损伤机制研究提供新线索，为防治尘肺提供新思路。

长期接触石英粉尘可引起职业病尘肺等健康损伤，尘肺以肺组织纤维化为特征，是我国发病最高的职业病，占职业病总数的80%以上。尘肺的发病机制尚不完全清楚，目前也缺乏有效治疗手段。为探索尘肺发病机制，本项目从石英粉尘引发的炎性反应和纤维化着手，通过巨噬细胞染尘、急慢性小鼠染尘动物模型和人群尘肺病例对照验证研究对TAM/Gas6通路在石英粉尘引起的炎性反应和肺部纤维化作用机制进行研究，研究显示：（1）Gas6可以抑制石英粉尘诱导巨噬细胞产生的炎性反应，拮抗Gas6后，染尘细胞分泌的炎性因子如IL-1β、TNF-α等水平升高，即炎性反应增加，补充外源性Gas6降低了巨噬细胞分泌的炎性因子和炎性反应；（2）TAM/Gas6在小鼠石英染尘模型中可调节石英致炎性反应及纤维化作用，拮抗Gas6或抑制TAM受体可增加石英诱导的炎性和纤维化反应，补充外源性Gas6具有抑制石英诱导炎性和纤维化反应的作用，研究结果还发现TAM的三个亚群在石英致炎性反应和纤维化作用不同，Mer亚群对纤维化影响更大；（3）尘肺病例对照研究发现尘肺患者及接尘工人的外周血白细胞中Tyro3 mRNA、Axl mRNA水平高于健康非接尘者，白细胞Gas6 mRNA水平和血浆Gas6水平低于非接尘者。结果提示：TAM/Gas6可负向调节石英引起的炎性反应和纤维化，补充Gas6可以显著降低石英粉尘引起的炎性反应和肺纤维。研究成果为完善尘肺发病机制提供了新思路，为尘肺防治提供了针对性靶点