Mitochondrial Structural and Functional Remodeling in Microglial Activation

小胶质细胞激活中的线粒体结构和功能重塑

基本信息

批准号：
9093229
负责人：
BRIAN M POLSTER
金额：
$ 23.1万
依托单位：
UNIVERSITY OF MARYLAND BALTIMORE
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-03-01 至 2018-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9093229
关键词：
Acute Affect Agonist Alzheimer&apos s Disease Animal Model Belief Bioenergetics Blinded Blood - brain barrier anatomy Brain Brain Injuries Cardiac Cells Chronic Complex Data Electron Microscopy Equilibrium Figs - dietary Flow Cytometry Genus Hippocampus Glycolysis Goals Heart Arrest Human Hydrogen Peroxide ITGAM gene Individual Injection of therapeutic agent Injury Interferon Type II Interferons Knock-out Knockout Mice Label Link Lipopolysaccharides Measures Microglia Mitochondria Modeling Morphology Mus NADPH Oxidase Nerve Degeneration Neurodegenerative Disorders Neurons Nitric Oxide Oxidative Phosphorylation PTPRC gene Parkinson Disease Pathology Pharmaceutical Preparations Population Pre-Clinical Model Production Proteins Quality Control Reactive Oxygen Species Respiration Reverse Transcriptase Polymerase Chain Reaction Role Secondary to Signal Transduction Staining method Stains Stroke TLR4 gene TNF gene Testing The Jackson Laboratory Thinking Time Traumatic Brain Injury brain cell brain tissue catalase cellular imaging cytokine in vivo in vivo Model inhibitor/antagonist mouse model neuroinflammation neuropathology novel novel therapeutics public health relevance research study response small molecule inhibitor targeted treatment trafficking

项目摘要

DESCRIPTION (provided by applicant): The mitochondrial fission-promoting protein Drp1 is linked to neuropathology in acute and chronic neurodegenerative disorders. Mdivi-1, a blood-brain barrier permeable drug thought to inhibit Drp1, protects the brain in preclinical models of stroke, cardiac arrest, and Parkinson's disease. While major efforts are underway to test whether targeting the mitochondrial fission-fusion balance in neurons can modify neurodisease, the implications of targeting mitochondrial fission in non-neuronal brain cells are almost entirely unexplored. We see a mitochondrial structural remodeling consistent with Drp1-dependent fission in microglia when they enter a proinflammatory activation state termed M1. A bioenergetic shift from oxidative phosphorylation to glycolysis promotes M1 activation, and activation is marked by production of nitric oxide (NO) and proinflammatory cytokines. Resembling the neuroinflammatory state seen in human brain injury, M1 activation can persist for months to years and result in additional pathology. A better understanding of the mechanisms contributing to M1 activation will help discover novel therapeutics that block the deleterious consequences of M1 microglial activation. We find that the Drp1 inhibitor mdivi-1 suppresses microglial NO and TNF-α production in response to lipopolysaccharide (LPS) ± interferon-γ. We also find that mdivi-1 can inhibit reactive oxygen species (ROS) production by mitochondrial complex I in a Drp1-independent fashion. It is important to determine whether one or both of the known mdivi-1 targets, Drp1 and ROS, contribute to M1 microglial activation in vivo, and thus represent bona fide targets for therapy. This study will test the central hypothesis that in vivo, Drp1 activity but not mitochondrial ROS is required for microglial activation and the accompanying shift in cellular bioenergetics. Microglial activation will be induced in mice by intracerebroventricular administration of LPS. To investigate the role of Drp1, a novel microglia-specific inducible knockout mouse model will be developed. In addition, the existing MCAT mouse ectopically expressing matrix-targeted, H2O2-detoxifying catalase will be used to evaluate a specific requirement for mitochondrial ROS independent of other ROS. In Aim 1, we will determine whether Drp1 is necessary for the bioenergetic shift and microglial M1 activation induced by LPS in vivo. In Aim 2, we will determine whether mitochondrial ROS are required for the bioenergetic shift and microglial M1 activation induced by in vivo LPS injection. Our studies will take a crucial step toward determining whether microglial mitochondria can be targeted for therapy. Since normal Drp1-dependent fission is required for mitochondrial trafficking and quality control in neurons, a strategy specifically targeting Drp1 in microglia may ultimately be more desirable than global inhibition of mitochondrial fission. Our long-term goal is to target mitochondrial mechanisms of microglial activation in models of ischemic and traumatic brain injury, with the ultimate hope of developing a protective therapy for humans.

描述（由适用提供）：线粒体裂变促进蛋白DRP1与急性和慢性神经退行性疾病的神经病理学有关。 MDIVI-1是一种抑制DRP1的血脑屏障渗透性药物，可保护大脑中风，心脏骤停和帕金森氏病。尽管正在进行重大努力来测试靶向神经元中线粒体裂变平衡是否可以改变神经酶酶，但靶向非神经元脑细胞中线粒体裂变的含义几乎完全完全是未探索。我们看到一种与小胶质细胞中DRP1依赖性裂变一致的线粒体结构重塑，当它们进入称为M1的促炎激活状态时。从氧化磷酸化到糖酵解的生物能转移会促进M1激活，并且激活以一氧化氮（NO）和促炎细胞因子的产生为标志。类似于人脑损伤中的神经炎症状态，M1激活可以持续数月至数年，并导致其他病理。更好地了解导致M1激活的机制将有助于发现新的疗法，从而阻止M1小胶质细胞激活的有害后果。我们发现DRP1抑制剂MDIVI-1抑制了小胶质细胞NO和TNF-α的产生，以响应脂多糖（LPS）±Interferon-γ。我们还发现，MDIVI-1可以以DRP1无关的方式抑制线粒体复合物I的活性氧（ROS）。重要的是要确定一个或两个已知的MDIVI-1靶标DRP1和ROS是否有助于体内M1小胶质细胞激活，因此代表了治疗的真正靶标。这项研究将检验中心假设在体内，DRP1活性而不是线粒体ROS是小胶质细胞激活和伴随细胞生物能学的转变。小胶质细胞活化将通过脑室室内的LPS诱导小鼠。为了研究DRP1的作用，将开发出一种新型的小胶质细胞特异性诱导敲除小鼠模型。此外，现有的MCAT小鼠以循环表达的矩阵靶向，H2O2-氧化过氧化氢酶将用于评估与其他ROS无关的线粒体ROS的特定需求。在AIM 1中，我们将确定DRP1是否对于LPS在体内诱导的生物能移位和小胶质细胞M1激活是否需要。在AIM 2中，我们将确定是否需要通过体内LPS注射引起的生物能移位和小胶质细胞M1激活的线粒体ROS。我们的研究将朝着确定小胶质细胞线粒体是否可以用于治疗的关键步骤。由于神经元中线粒体运输和质量控制需要正常的DRP1依赖性裂变，因此特异性针对小胶质细胞中DRP1的策略最终可能比全球对线粒体裂变的抑制更为可取。我们的长期目标是针对缺血性和创伤性脑损伤模型中小胶质细胞激活的线粒体机制，并最终希望为人类开发保护性疗法。