Mitochondrial DNA Damage and Inflammasome Activation in Vascular Inflammation

摘要 在美国，动脉粥样硬化性心脏病是导致死亡的主要原因。慢性炎症是一个关键 这一过程的组成部分和炎症的操纵可能会产生新的治疗方法。最近的研究 强调IL-1是慢性炎症（包括血管炎）中的关键炎症细胞因子， 动脉粥样硬化，中和2型糖尿病和动脉粥样硬化中IL-1的临床试验正在进行中。 以前的研究表明IL-1和细胞凋亡在斑块进展中起关键作用，但没有机制 这两个过程之间的联系以及IL-1被激活的确切机制 直到现在才知道。我们最近发现了NLRP 3炎性小体的难以捉摸的机制 激活IL-1产生，并将凋亡和线粒体（Mt）氧化DNA损伤与此相关。 通路我们发现，诱导线粒体功能障碍的危险信号和线粒体中的ROS， 释放到细胞溶质中的（氧化的）mtDNA，在那里它结合并激活NLRP 3炎性体， 制造活性IL-1的机制。基于这些最近的开创性发现，本文的主要目标 R21的探索性建议是研究线粒体DNA损伤在细胞凋亡和诱导过程中的作用 研究IL-1与血管炎症和动脉粥样硬化的关系， 预防和治疗这种疾病的方法。我们将操纵线粒体DNA修复系统来研究 它作为一种新的治疗策略的潜力，将防止IL-1的激活（以及IL-18-其他 NLRP3依赖性细胞因子），而不是目前的策略，以中和IL-1后，它已经释放 并导致下游激活。基于这些关键发现，我们提出了以下两个目标， 围绕中心假设，即在血管炎症过程中发生的线粒体DNA氧化损伤 激活NLRP3炎性小体产生IL-1？，并在 抑制氧化性DNA损伤将防止NLRP 3炎性体活化， 结果减少血管炎症和动脉粥样硬化。具体目的1-定义的作用， 在饮食诱导的高胆固醇血症中NLRP3炎性体激活期间的线粒体DNA损伤 使用DNA损伤修复基因Ogg1.AIM 2缺陷的小鼠建立动脉粥样硬化小鼠模型 研究通过合成的8-OH-dG阻断线粒体DNA诱导的NLRP 3活化的治疗作用 给药，并确定Ogg1基因转移增强Mt DNA修复的作用。

ABSTRACT Atherosclerotic heart disease is the leading cause of death in the USA. Chronic inflammation is a key component of this process and manipulation of inflammation may yield novel treatments. Recent studies have highlighted IL-1¿, as a key inflammatory cytokine in chronic inflammation, including vasculitis and atherosclerosis, and clinical trials are underway to neutralize IL-1¿ in type 2 diabetes and atherosclerosis. Previous studies showed a key role of IL-1¿ and apoptosis in plaque progression, but no mechanistic connections were drawn between these two processes and the exact mechanism by which IL-1¿is activated was not known until now. We have recently discovered the elusive mechanism of NLRP3 inflammasome activation for IL-1¿production, and linked apoptosis and mitochondrial (Mt) oxidative DNA damage to this pathway. We showed that danger signals that induce Mt dysfunction and ROS in the Mt, result in damaged (oxidized) mtDNA that is released into the cytosol where it binds to and activates the NLRP3 inflammasome, the machinery by which active IL-1¿ is made. Based on these recent seminal findings, the main goal of this exploratory R21 proposal is to investigate the role of mtDNA damage during apoptosis and induction of IL-1¿ as it relates to vascular inflammation and atherosclerosis in order to find novel and more efficient ways to prevent and treat this disease. We will manipulate the mitochondrial DNA repair system to investigate its potential as a new treatment strategy that would prevent the activation of IL-1¿ (as well as IL-18- the other NLRP3-dependent cytokine), as opposed to current strategies to neutralize IL-1¿ after it is already released and led to downstream activation. Based upon these key findings, we propose the following two Aims focused around the central hypothesis that oxidative mtDNA damage that occurs during vascular inflammation activates the NLRP3 inflammasome for IL-1¿production and plays a proinflammatory role in atherogenesis.Inhibition of oxidative DNA damage will prevent NLRP3 inflammasome activation and result in decreased vascular inflammation and atherosclerosis.Specific AIM 1- To define the role of mitochondrial DNA damage during NLRP3 inflammasome activation in a diet-induced hypercholesterolemic mouse models of atherosclerosis using mice deficient in the DNA damage repair gene Ogg1.AIM 2- To investigate the therapeutic role of blocking mitochondrial DNA induced NLRP3 activation by synthetic 8-OH-dG administration and to determine the role of augmenting the Mt DNA repair with Ogg1 gene transfer.