Mitochondrial DNA: a target and effector of pulmonary epithelial cell injury

 描述（由申请人提供）：肺上皮细胞是各种肺部疾病发病机制中的关键效应物以及靶标。气道中的氧化应激已被认为是哮喘、慢性阻塞性肺疾病、急性呼吸窘迫综合征和包括肺癌在内的其他肺部疾病期间肺损伤发展的早期事件。高氧合组织如肺特别容易发生氧化应激损伤。虽然线粒体DNA对氧化剂诱导的损伤高度敏感，但尚未研究线粒体DNA损伤与肺上皮细胞损伤的致病作用。基于我们在体外和体内的初步数据，我们提出了一个新的假设，即受损的线粒体DNA作为一种新的哨兵分子在诱导肺上皮细胞的促炎反应的最早阶段。与核DNA相反，线粒体DNA包括细菌DNA的几个特征，使其在诱导炎症反应方面特别有效。通过阐明线粒体DNA损伤在促进肺部炎症中的积极作用，该项目有望确定新的治疗方向，以改善其负面结果。我们的假设将通过体外和体内研究相结合进行全面评估，目的如下：目的1。阐明线粒体DNA特异性损伤在体外促炎信号传导中的作用;通过分析关键线粒体和细胞功能的变化，以及促炎反应的信号传导途径，包括氧化线粒体DNA释放机制和DNA敏感受体;所有这些都是对线粒体DNA特异性损伤的反应。目标二。通过对小鼠肺线粒体DNA氧化损伤、肺泡灌洗液中氧化线粒体DNA的存在以及气道炎症反应之间的联系进行综合分析，阐明线粒体DNA损伤在体内肺部炎症反应中的致病作用。自由基生物学和DNA损伤领域的先前观点是，DNA损伤是氧化性和炎性肺损伤的下游结果。相比之下，我们的项目将建立一个新的范例，在肺部炎症性疾病的发病机制，通过证明线粒体DNA损伤作为一个早期的致病步骤，诱导炎症性肺反应。了解这一过程的分子机制有可能制定新的治疗方法。我们在DNA修复/损伤，线粒体病理学和合作者组装方面的独特专业知识使我们非常适合承担这个项目。此外，R21是理想的创始机制，为初级教师，以发展成功的R 01应用程序在不久的将来。

 DESCRIPTION (provided by applicant): Pulmonary epithelial cells are key effectors as well as targets in the pathogenesis of various lung diseases. Oxidative stress in airways has been implicated as an early event in development of lung injury during asthma, chronic obstructive pulmonary disease, acute respiratory distress syndrome and other lung diseases including lung cancer. Highly oxygenated tissues such as lungs are particularly prone to oxidative stress injury. Although mitochondrial DNA is highly susceptible to oxidant-induced damage, the pathogenic role of mitochondrial DNA damage has not been investigated in connection to the lung epithelial cell injury. Based on several lines of our in vitro and in vivo preliminary data, we put forward th novel hypothesis that damaged mitochondrial DNA acts as a novel sentinel molecule at the earliest phase of the induction of pro-inflammatory response in pulmonary epithelial cells. Mitochondrial DNA, as opposed to nuclear DNA, includes several characteristic features of bacterial DNA, making it particularly potent in inducing inflammatory response. By unraveling the active role of mitochondrial DNA damage in the promotion of pulmonary inflammation, this project is expected to identify new therapeutic directions to ameliorate its negative outcome. Our hypothesis will be comprehensively evaluated by combination of in vitro and in vivo studies by following aims: Aim 1. To elucidate the role of mitochondrial DNA-specific damage in the development of pro-inflammatory signaling in vitro; by analyzing changes of critical mitochondrial and cellular functions, and signaling pathways of the pro- inflammatory response including mechanism of oxidized mitochondrial DNA release and DNA-sensing receptors; all in response to mitochondrial DNA-specific damage. Aim 2. To elucidate the causative role of the mitochondrial DNA damage in the pulmonary inflammatory response in vivo by comprehensive analysis of the connection between oxidative damage to the mitochondrial DNA in the lungs, the presence of oxidized mitochondrial DNA in the alveolar lavage fluid, and inflammatory response in mouse airways. The previous view in the field of free radical biology and DNA injury was that damage to the DNA is a downstream consequence of oxidative and inflammatory lung injury. In contrast, our project will establish a new paradigm in the pathogenesis of pulmonary inflammatory diseases by demonstrating that mitochondrial DNA damage acts as an early causative step in induction of the inflammatory lung response. Understanding the molecular mechanisms of this process has the potential to formulate novel therapeutic approaches. Our unique expertise in DNA repair/damage, mitochondrial pathobiology and assembly of the collaborators makes us ideally suited to undertake this project. Moreover, R21 is ideal founding mechanism for junior faculty in order to develop successful R01 application in the near future.