mtDNA DAMPS: a pharmacologic target in multi-organ system failure

 描述（由申请人提供）：通过K 08机制进行研究培训的申请来自一位创伤外科医生和重症监护专家，他已经担任助理教授三年。他现在提出了一个多维的培训计划，旨在启动他的学术生涯作为一个基本的和翻译外科医生科学家，并专注于创伤和重症监护医学中最普遍的问题之一，特别是多器官系统衰竭（MOSF）。培训计划-物理位于高度跨学科和资金充足的中心肺生物学和该地区唯一的水平 1创伤中心-旨在为候选人提供（1）核心知识和实验室技能，（2）研究方法和生物统计学方面的最新专业知识，以及（3）科学写作，演讲和学术领导技能。将利用教学课程，明智地出席现场和场外研讨会和会议，以及密集的实验室经验来实现这些目标。提出的研究计划的动机是两个显着的差距与MOSF患者的护理。首先，虽然严重损伤的结果有所改善，部分原因是复苏和支持治疗的进步，MOSF仍然是一个严重的临床问题，因为尚未开发出预防或逆转综合征的药理学策略。第二，虽然线粒体和生物能量功能障碍长期以来被认为是对严重损伤的反应，但整合细胞对全身性炎症反应的关键哨兵分子存在于这些线粒体和生物能量异常中的前景以前没有被考虑过。因此，候选人的研究培训计划将测试线粒体DNA（mtDNA）作为控制MOSF中有害细胞反应的分子哨兵的新概念。多条线索的证据都集中在这个想法上。线粒体基因组比核DNA对氧化损伤更敏感，这一观察结果的重要性通过MOSF谱中氧和氮（RS）的反应性物种的参与而得到强调。此外，使用转基因策略或新型平台药物调节mtDNA修复效率协调地决定了在氧化剂或细菌攻击的培养细胞、分离的器官和完整动物中的存活和功能。最明显的是，最近的证据表明mtDNA是MOSF的细胞间介质。损伤后释放到循环中的线粒体基因组片段-称为线粒体DNA损伤相关分子模式（DAMP）-可能通过TLR介导的炎症和驻留细胞活化将损伤从初始损伤部位传播到远处器官（19）。由于mtDNA DAMP处置的分子决定因素完全未被探索，因此拟议的研究将测试具有预防意义的假设，即在严重创伤中，线粒体基因组的氧化碱基损伤导致mtDNA DAMP的血浆积累，从而导致MOSF的演变。在严重创伤患者、人外周血单个核细胞（PBMC）和啮齿动物MOSF模型中的研究将：（1）确定严重创伤患者血浆mtDNA DAMP水平与MOSF指数之间的关系;（2）在人PBMC中检验氧化剂介导的mtDNA损伤和mtDNA修复动力学分别为正和负的假设，与mtDNA DAMP释放到细胞外环境中相关;和（3）确定在铜绿假单胞菌诱导的脓毒症的大鼠模型中，用新型平台药物增加的mtDNA修复和增强的mtDNA DAMP降解是否预防和逆转MOSF。总的来说，这项研究将提供第一个观察证据，将血浆mtDNA DAMP与严重受伤患者的脆弱人群中MOSF的演变联系起来。然而，其最具创新性和最重要的贡献涉及通过提供增强mtDNA修复和加速mtDNA DAMP降解的策略抑制mtDNA DAMP积累和器官衰竭传播的概念验证来鉴定MOSF中用于药物干预的分离靶标。相信在这个培训项目结束时，候选人将很好地定位于启动第一个关于控制严重损伤中mtDNA DAMP介导MOSF策略临床试验。此外，候选人将开创一个独立的实验室研究计划，其目标将是在分子水平上定义新的药理学靶点，以管理创伤和其他疾病中的mtDNA DAMP处置，这些细胞内和细胞内介质发挥致病作用。

 DESCRIPTION (provided by applicant): This application for research training via the K08 mechanism originates from a trauma surgeon and critical care specialist that has been an assistant professor for three years. He now proposes a multi-dimensional training program intended to launch his academic career as a basic and translational surgeon-scientist and focused on one of the most pervasive problems in trauma and critical care medicine, specifically, multiple organ system failure (MOSF). The training program - physically located in the highly interdisciplinary and well-funded Center for Lung Biology and in the region's only level 1 Trauma Center - is intended to provide the candidate with (1) core knowledge and laboratory skills, (2) state-of-the-art expertise in research methods and biostatistics, and (3) scientific writing, presentation, and academic leadership skills. A combination of didactic courses, judicious attendance at on-site and off-site seminars and meetings, and intense laboratory experiences will be utilized to achieve these goals. The proposed research plan is motivated by two striking gaps in the care of patients with MOSF. First, although outcomes of severe injury have improved partly as a consequence of advances in resuscitation and supportive care, MOSF remains a serious clinical problem because pharmacologic strategies to prevent or reverse the syndrome have yet to be developed. Second, while mitochondrial and bioenergetic dysfunction have long been incriminated in the response to severe injury, the prospect that key sentinel molecule(s) integrating cellular responses to systemic inflammation reside in these mitochondrial and bioenergetic abnormalities has not previously been considered. Accordingly, the candidate's research training plan will test the novel concept that mitochondrial DNA (mtDNA) acts as a molecular sentinel governing deleterious cell responses in MOSF. Multiple lines of evidence converge on this idea. The mitochondrial genome is far more sensitive to oxidative damage than nuclear DNA, an observation whose significance is underscored by involvement of reactive species of oxygen and nitrogen (RS) across the spectrum of MOSF. Further, modulation of mtDNA repair efficiency using transgenic strategies or novel platform drugs coordinately dictate survival and function in oxidant or bacteria-challenged cultured cells, isolated organs, and intact animals. Most provocatively, recent evidence incriminates mtDNA as an intercellular mediator of MOSF. Fragments of the mitochondrial genome released into the circulation after injury - termed mtDNA Damage Associated Molecular Patterns (DAMPs) - may serve to propagate damage from the initial site of injury to distant organs through TLR-mediated activation of inflammatory and resident cells (19). Because molecular determinants of mtDNA DAMP disposition are entirely unexplored, the proposed research will test the translationally-significant hypothesis that in severe trauma, oxidative base damage to the mitochondrial genome causes plasma accumulation of mtDNA DAMPs resulting in the evolution of MOSF. Studies in severely injured human patients, human peripheral blood mononuclear cells (PBMCs), and in a rodent model of MOSF will: (1) Define relationships between plasma mtDNA DAMP levels and indices of MOSF in patients with severe trauma; (2) Test the hypothesis in human PBMCs that oxidant- mediated mtDNA damage and mtDNA repair kinetics are positively and negatively, respectively, associated with mtDNA DAMP release into the extracellular environment; and, (3) Determine if increased mtDNA repair and enhanced mtDNA DAMP degradation with novel platform drugs, prevents and reverses MOSF In a rat model of Pseudomonas aeruginosa-induced sepsis. Collectively, this research will provide the first observational evidence linking plasma mtDNA DAMPs to the evolution of MOSF in a vulnerable population of severely injured patients. However, its most innovative and significant contributions relate to the identification of isolated targets for pharmacologic intervention in MOSF by providing proof-of-concept that strategies to augment mtDNA repair and accelerate mtDNA DAMP degradation suppress mtDNA DAMP accumulation and propagation of organ failure. It is believed that at the end of this training program, the candidate will be well positined to launch the first clinical trials on strategies to control mtDNA DAMP- mediated MOSF in severe injury. In addition, the candidate will inaugurate an independent laboratory research program whose goal will be define at a molecular level novel pharmacologic targets to govern mtDNA DAMP disposition in trauma and other disorders for which these inter- and intracellular mediators play pathogenic role.