锑靶向线粒体致呼吸系统上皮细胞损伤作用及机制研究

With the rapid development of antimony mining and smelting and antimony processing industry, public concerns have been raised on the health hazards of occupational antimony exposure. Epidemiological studies have indicated that antimony exposure was associated with increased risks of different respiratory diseases, including lung injury and pneumoconiosis. Laboratory studies showed that oxidative stress plays a key role in antimony-induced cell injury. However, the mechanism of antimony induced oxidative stress, e.g., induction of reactive oxygen species (ROS), remain unclear. In bronchiolar epithelium BEAS-2B cells and alveolar epithelium A549 cells, we found that exposure to antimony increased cellular ROS levels and inhibited cell viability, while mitochondrial ROS scavenger significantly attenuated antimony-induced cell injury. Interestingly, our preliminary results showed that antimony induced mitochondrial dysfunction and could be enriched in mitochondria. These novel findings drive us to propose a hypothesis that exposure to antimony induced cell injury may be through oxidative stress by direct targeting mitochondria. In this proposal, we will 1) investigate the temporal and spatial pattern that antimony was transported into mitochondria; 2) identify specific types of mitochondrial ROS induced by antimony and elucidate the source of ROS; 3) screen the candidate proteins associated with mitochondria that may interact with antinomy by HPLC-MS/MS and explore the role of the key interacting protein involved in antimony-induced ROS. We expect to elucidate the molecular mechanisms on antimony-induced oxidative stress in bronchiolar and alveolar epithelium cells by targeting mitochondria, which may provide preventive and therapeutic targets for lung injury induced by antimony.

随着锑矿开采、冶炼及锑加工相关产业的发展，职业性锑暴露人群增多，潜在的健康危害越来越受到关注。锑主要经呼吸系统进入人体，引起上呼吸道刺激症状、急慢性肺损伤和尘肺等。研究显示，锑暴露主要通过氧化应激途径引起细胞损伤，但锑诱导氧自由基（ROS）产生的机制仍不清楚。我们的前期研究发现，线粒体ROS清除剂能显著抑制锑暴露引起的支气管和肺泡上皮细胞损伤，且锑能影响线粒体功能并在线粒体中富集，提示锑可能通过靶向线粒体诱导氧化应激引起细胞损伤。为此，本项目拟在细胞和亚细胞水平分析锑进入线粒体的时间和空间分布特征以及锑致线粒体ROS增加的种类和途径；然后，利用液质联用技术等筛选鉴定锑靶向线粒体的相互作用蛋白，并利用生化分析、分子细胞生物学等实验技术分析关键蛋白在锑诱导ROS生成中的作用。本项目研究预期探索阐明锑靶向线粒体引起氧化应激致细胞损伤的分子机理，研究成果将有望为锑暴露致肺损伤防治提供靶点。

随着锑矿开采、冶炼及锑加工相关产业的发展，职业性锑暴露人群增多，职业性锑暴露的.健康危害越来越受到关注。职业性锑暴露主要经呼吸系统进入人体，引起上呼吸道刺激症状、.急慢性肺损伤和尘肺等，但锑致肺损伤的作用机理仍不清楚。我们的前期研究发现，锑暴露主要通过氧化应激途径引起呼吸系统上皮细胞损伤，且氧自由基（ROS）主要来源于线粒体。为深入探索锑诱导ROS产生的机制，本项目在前期研究的基础上以支气管上皮细胞和肺上皮细胞为模型，在细胞和亚细胞水平明确锑在细胞内的分布、锑致线粒体ROS增加的种类和方式，以及锑致线粒体功能紊乱。项目初步提出锑致呼吸系统细胞损伤机制，即锑主要富集于线粒体，通过破坏线粒体氧化还原平衡，进而影响线粒体功能，造成细胞损伤。需要指出的是，项目组研究未能预期筛选到锑作用的线粒体候选蛋白，还有待于后期通过其它技术方法完善。项目研究阐明锑靶向线粒体损伤细胞的分子机理，研究成果可助于为锑致肺损伤干预提供靶点。