Mitochondrial modulation for neuroprotection in a model of multiple sclerosis

多发性硬化症模型中线粒体调节的神经保护作用

基本信息

批准号：
7463230
负责人：
Dennis Neil Bourdette
金额：
$ 33.69万
依托单位：
OREGON HEALTH & SCIENCE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-04-01 至 2013-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7463230
关键词：
Acute Attention Axon Bioenergetics Brain Calcium Cell Death Clinical Demyelinations Development Disease Drug usage Encephalomyelitis Endopeptidases Energy Supply Event Experimental Autoimmune Encephalomyelitis Face Free Radicals Genes Goals Immune response Immunosuppressive Agents In Vitro Inflammation Inflammation Mediators Inflammatory Inflammatory Response Injury Intervention Knock-out Knowledge Lead Link Mediating Mediator of activation protein Metabolism Mitochondria Mitochondrial Proteins Modeling Molecular Molecular Target Multiple Sclerosis Mus Mutant Strains Mice Nerve Nerve Fibers Neuraxis Neuronal Injury Neurons Nitrogen Oxygen Pan Genus Paralysed Pathologic Pathway interactions Peptide Hydrolases Permeability Pharmaceutical Preparations Play Process Production Proteins Public Health Regulation Research Resistance Role Severity of illness Site Spinal Cord Testing Therapeutic Wild Type Mouse cell growth regulation cell type cyclophilin D disability mitochondrial dysfunction mitochondrial permeability transition pore neuroprotection novel novel therapeutics prevent protective effect recombinase respiratory response stem therapeutic target

项目摘要

DESCRIPTION (provided by applicant): The long term objective of this research is to identify molecular targets for neuroprotective therapies in multiple sclerosis (MS). It is now recognized that axon damage occurs commonly in MS and is an important cause of permanent disability. Developing neuroprotective therapies that halt axonal degeneration is a major therapeutic goal of MS research. Although the precise mechanisms leading to axonal degeneration are poorly understood, they most likely stem from a cascade of ionic imbalances initiated by mitochondrial dysfunction and concomitant deficits in cellular energy supply, ultimately resulting in mitochondrial and axonal Ca2+ overload. Using the murine model of MS, experimental autoimmune encephalomyelitis (EAE), we have demonstrated that mouse mutants missing cyclophilin D (CyPD-KO), a key regulator of the mitochondrial permeability transition (PT) pore and the major pathway for Ca2+ release from mitochondria, have dramatically reduced axonal damage compared with wild type (WT) mice despite the presence of inflammation within the central nervous system (CNS). CyPD-KO mice develop acute EAE similar to WT mice but unlike the WT mice, recover clinically and show up to an 80% reduction in axonal damage. Importantly, mitochondria from CyPD-KO mice are resistant to Ca2+-mediated PT Pore activation and primary cortical neurons from CyPD-KO mice resist injury induced by oxygen and nitrogen free radicals, mediators of injury in EAE and MS. These results suggest a critical role for the PT Pore in determining the fate of axons in EAE and MS. The guiding hypothesis of this proposal is that modulation of the PT Pore by inactivation of CyPD will enhance the ability of axonal mitochondria to sequester Ca2+ in response to pathologic increases in Ca2+, thereby delaying activation of the PT Pore. In turn, inhibition of PT Pore activation will abrogate ATP depletion, axoplasmic Ca2+ overload, and the initiation of a molecular cascade that leads to axonal destruction. We propose the following specific aims to further test the role of the mitochondrial PT Pore and its modulation by CyPD inactivation in the development of axonal injury in EAE. In Aim 1, we will use CyPDloxP/neuronal Cre mice to determine whether inactivation of CyPD in neurons and their axons and not in other CNS cell types results in axonal protection in EAE. In Aim 2, we will use primary cortical neuronal cultures from WT and CyPD-KO mice to determine whether toxic inflammatory mediators generated during EAE 1) change dendritic stability and neuronal viability in WT neurons and 2) increase mitochondrial Ca2+ levels and activate the PT Pore in these neurons and whether 3) CyPD inactivation inhibits these effects. In Aim 3, we will determine whether drugs that inactivate CyPD protect axons in EAE and cortical neurons in vitro. Our results will expand our knowledge of how modulation of mitochondrial PT Pore responses influence axonal injury in EAE and MS, facilitating the development of novel neuroprotective therapies for the treatment of MS. PUBLIC HEALTH RELEVANCE: Our research seeks to understand how to prevent damage to nerve fibers in the spinal cord of mice with a multiple sclerosis-like disease. We have found that we can dramatically reduce damage to nerves in this multiple sclerosis-like disease by blocking a protein in mitochondria. The results of this research should lead to new treatment approaches for multiple sclerosis by using drugs to block the mitochondrial protein.

描述（由申请人提供）：这项研究的长期目标是确定多发性硬化症（MS）中神经保护疗法的分子靶标。现在已经认识到，轴突损伤通常发生在MS中，是永久残疾的重要原因。开发导致轴突变性的神经保护疗法是MS研究的主要治疗目标。尽管对导致轴突变性的确切机制了解鲜为人知，但它们很可能源自线粒体功能障碍和细胞能量供应中伴随的缺陷引发的一系列离子失衡，最终导致线粒体和轴突CA2+超负荷。 Using the murine model of MS, experimental autoimmune encephalomyelitis (EAE), we have demonstrated that mouse mutants missing cyclophilin D (CyPD-KO), a key regulator of the mitochondrial permeability transition (PT) pore and the major pathway for Ca2+ release from mitochondria, have dramatically reduced axonal damage compared with wild type (WT) mice despite the presence of中枢神经系统（CNS）内的炎症。 CYPD-KO小鼠会产生与WT小鼠相似的急性EAE，但与WT小鼠不同，临床恢复并显示出轴突损伤的80％。重要的是，来自CYPD-KO小鼠的线粒体具有对Ca2+介导的PT孔激活的抗性，而CYPD-KO小鼠的原代皮质神经元抵抗了氧气和氮气自由基诱导的损伤，EAE和MS的损伤介体。这些结果表明，PT孔在确定EAE和MS中轴突的命运方面起着关键作用。该提议的指导假设是，通过CYPD灭活PT孔的调节将增强轴突线粒体隔离Ca2+的病理增加的能力，从而延迟PT孔的激活。反过来，抑制Pt孔的激活将消除ATP耗竭，轴突CA2+过载，以及导致轴突破坏的分子级联反应的启动。我们提出了以下特定目的，以进一步测试线粒体PT孔的作用及其通过CYPD失活在EAE轴突损伤发展中的调节。在AIM 1中，我们将使用CypDloxP/神经元CRE小鼠来确定神经元及其轴突中CYPD的失活是否是否会导致EAE中的轴突保护。在AIM 2中，我们将使用来自WT和CYPD-KO小鼠的原发性皮质神经元培养物来确定EAE期间产生的有毒炎性介质是否在WT神经元中改变树突状稳定性和神经元的可行性，并且2）增加了线粒体Ca2+水平并激活这些神经元中的PT孔和3）cypd。在AIM 3中，我们将确定在体外灭活CYPD的药物是否保护EAE和皮质神经元中的轴突。我们的结果将扩大我们对线粒体PT孔反应的调节如何影响EAE和MS中轴突损伤的知识，从而促进了新型神经保护疗法的发展以治疗MS。公共卫生相关性：我们的研究试图了解如何防止患有多发性硬化症的小鼠脊髓中对神经纤维的损害。我们发现，通过阻断线粒体中的蛋白质，我们可以大大减少这种多发性硬化症样疾病中神经的损害。这项研究的结果应通过使用药物阻断线粒体蛋白来导致多发性硬化症的新方法。