White Matter Protection in Cerebral Ischemia

脑缺血中的白质保护

基本信息

批准号：
9292388
负责人：
GUODONG CAO
金额：
$ 33.69万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-07-01 至 2019-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9292388
关键词：
Accounting Affect Animals Area Blood Blood - brain barrier anatomy Brain Brain Diseases Cause of Death Cell Death Cells Cerebral Ischemia Cerebral cortex Cerebrum Cessation of life Clinic Clinical Clinical Treatment Communication Cytosol Demyelinations Endothelin-1 Enzymes Extracellular Space Glucose Goals Human Infarction Injury Internal Capsule Interneurons Intervention Ischemia Ischemic Brain Injury Ischemic Stroke Lead Lesion Light Mediating Microglia Microinjections Middle Cerebral Artery Occlusion Molecular Mus Myelin Natural regeneration Neurological outcome Neurons Nicotinamide Mononucleotide Nicotinamide adenine dinucleotide Oligodendroglia Oxygen Pathologic Phagocytosis Pilot Projects Play Principal Investigator Production Proteins Quality of life Recombinant Proteins Recombinants Research Role Signal Pathway Signal Transduction Source Stem cells Stroke Synapses System Testing Therapeutic Toxic effect Transgenic Mice Transgenic Organisms brain dysfunction clinically relevant deprivation disability enzyme biosynthesis extracellular functional disability functional outcomes gray matter improved in vivo ineffective therapies insight intraperitoneal macrophage neglect neuroprotection neurotransmission nicotinamide phosphoribosyltransferase novel overexpression post stroke programs promoter protective effect public health relevance stroke treatment therapeutic target treatment trial vector white matter white matter injury

项目摘要

DESCRIPTION (provided by applicant): Cerebral white matter is highly vulnerable to cerebral ischemia13 and white matter injury (WMI) is a major cause of functional disability in stroke, the nation's third leading cause of death and the leading cause of permanent disability. Thus, interventions targeted at WMI, an area that remains relatively understudied and poorly understood, may significantly improve post-stroke quality of life. Nicotinamide phosphoribosyltransferase (NAMPT) primarily localizes in the cytosol and functions as the rate-limiting enzyme for the biosynthesis of nicotinamide adenine dinucleotide (NAD)14. NAMPT is neuroprotective against cerebral ischemia15,16. In non-CNS systems, NAMPT can be found in the extracellular space (eNAMPT) and circulates systemically in the blood. Whether the CNS also has eNAMPT and the role of this eNAMPT remains unknown. In our pilot studies, we first detected that neural cells secrete NAMPT into the extracellular space and that eNAMPT, but not its intracellular counterpart (iNAMPT), is selectively induced after ischemia, implying that extracellular NAMPT may play a role in ischemia. Increased NAMPT levels are present in the extracellular space and in white matter after ischemia in neuron-specific transgenic mice. Most importantly, in addition to gray matter protection, we found that NAMPT transgenic overexpression protects against WMI after ischemia. These findings lead us to speculate that extracellular NAMPT may mediate white matter protection after ischemia. In line with this, we found that recombinant NAMPT protein protects oligodendrocytes against ischemia-like injury induced by oxygen glucose deprivation (OGD) and AMPA toxicity. More importantly, we found that exogenously administered NAMPT protein can cross the blood brain barrier and protect against ischemic WMI in vivo. Further studies found that recombinant NAMPT protein protects against cell death of oligodendrocytes and its progenitor cells (OPCs) induced by ischemia, and enhances the differentiation of OPCs into mature oligodendrocytes. These findings suggest that NAMPT may directly protect against WMI via inhibiting oligodendrocyte death and enhancing the maturation of OPCs. We found that NAMPT also enhances microglial myelin phagocytosis. This is important because damaged myelin is believed to suppress the maturation of OPCs and cause demyelination in many pathological conditions. Thus NAMPT may indirectly enhance oligodendrogenesis via modulating microglial myelin phagocytosis. The objective of this project is to further test the white matter protective effect of NAMPT and its underlying mechanisms, and to develop a novel and clinically relevant therapeutic approach for white matter protection after cerebral ischemia. The central hypothesis to be tested is that NAMPT protects against WMI via enhancing oligodendrocytic protection/ regeneration and microglia-mediated myelin phagocytosis. Focal ischemia will be induced in mice by middle cerebral artery occlusion (MCAO) The following Specific Aims are proposed: Aim 1: Test the hypothesis that systemic administration of NAMPT protein protects against WMI induced by focal ischemia. The proposed study will test the potential translational value of NAMPT in treating WMI induced by focal cerebral ischemia. NAMPT recombinant protein will be administrated intraperitoneally to mice and the effect of NAMPT on ischemic brain injury will be quantitatively evaluated. The endpoints for assessment include infarct volume, WMI, and neurological outcomes. Aim 2: Test the hypothesis that NAMPT protects against WMI by inhibiting oligodendrocytic death and enhancing oligodendrogenesis after cerebral ischemia. The proposed study will test whether systemic administration of NAMPT protein reduces oligodendrocyte death after focal ischemia. We will also test whether NAMPT stimulates the regeneration of oligodendrocytes after ischemia. Aim 3: Test the hypothesis that NAMPT protects against WMI by enhancing microglial myelin phagocytosis. Two approaches will be used to elevate NAMPT levels: systemic administration of NAMPT protein and microglia-targeted NAMPT overexpression via an AAV9 vector driven by microglia/macrophage specific F4/80 promoter. The effect of NAMPT on microglial myelin phagocytosis, oligodendrogenesis, WMI, and functional outcomes after ischemia will be evaluated. PHS 398/2590 (Rev. 06/09) Page Continuation Format Page

描述（由申请人提供）：脑白质高度容易受到脑缺血13的影响，而白质损伤（WMI）是中风功能障碍的主要原因，这是美国第三大死亡的主要原因，也是永久残疾的主要原因。因此，针对WMI的干预措施（该领域仍然相对研究且理解较低，可能会显着改善中风后生活质量。烟酰胺磷酸糖基转移酶（NAMPT）主要定位在细胞质中，并用作烟酰胺腺苷二核苷酸（NAD）14的生物合成的限速酶。 NAMPT对脑缺血15,16具有神经保护作用。在非CNS系统中，可以在细胞外空间（ENAMPT）中找到NAMPT，并在血液中系统地循环。中枢神经系统是否也具有着迷，并且该eNAMPT的作用仍然未知。在我们的试点研究中，我们首先检测到神经细胞将nampt分泌到细胞外空间中，而在缺血后，它被选择性地诱导了细胞外空间，而不是其细胞内对应物（INAMPT），这意味着细胞外NAMPT可能在缺血中起作用。在神经元特异性转基因小鼠缺血后的细胞外空间和白质中存在NAMPT水平的增加。最重要的是，除了灰质保护外，我们还发现，NAMPT转基因过表达可预防缺血后的WMI。这些发现使我们推测细胞外nampt可能介导缺血后的白质保护。与此相一致，我们发现重组NAMPT蛋白可以保护少突胶质细胞免受氧气葡萄糖剥夺（OGD）和AMPA毒性引起的缺血样损伤。更重要的是，我们发现外源施用的NAMPT蛋白可以越过血脑屏障并预防体内缺血性WMI。进一步的研究发现，重组NAMPT蛋白可以预防缺血诱导的少突胶质细胞及其祖细胞（OPC）的细胞死亡，并增强了OPC分化为成熟的少突胶质细胞。这些发现表明，NAMPT可以通过抑制少突胶质死亡并增强OPC的成熟来直接保护WMI。我们发现NAMPT还增强了小胶质髓磷脂吞噬作用。这很重要，因为被认为受损的髓磷脂会抑制OPC的成熟并在许多病理条件下引起脱髓鞘。因此，NAMPT可以通过调节小胶质细胞吞噬作用来间接增强寡构成。该项目的目的是进一步测试NAMPT及其潜在机制的白质保护作用，并在脑缺血后开发一种新型且与临床相关的治疗方法，以保护白质保护。要测试的中心假设是，NAMPT通过增强少突胶质细胞保护/再生和小胶质细胞介导的髓磷脂吞噬作用来预防WMI。局部缺血将通过脑中动脉闭塞（MCAO）在小鼠中诱导以下特定目的：目标1：检验假说，即nampt蛋白的全身施用可预防由局灶性局部缺血引起的WMI。拟议的研究将测试NAMPT在治疗局灶性脑缺血引起的WMI中的潜在翻译价值。 NAMPT重组蛋白将腹膜内延伸至小鼠，NAMPT对缺血性脑损伤的影响将进行定量评估。评估的终点包括梗塞量，WMI和神经系统结果。 AIM 2：检验以下假设：NAMPT通过抑制少突胶质性死亡并增强脑缺血后的寡肾上腺素发生来预防WMI。拟议的研究将测试NAMPT蛋白的全身施用是否会减少局灶性缺血后的少突胶质细胞死亡。我们还将测试NAMPT是否刺激缺血后少突胶质细胞的再生。 AIM 3：检验nampt通过增强小胶质细胞吞噬作用来预防WMI的假设。将使用两种方法来提高NAMPT水平：通过由小胶质细胞/巨噬细胞特异性F4/80启动子驱动的AAV9载体，全身施用NAMPT蛋白和靶向小胶质细胞的NAMPT过表达。将评估NAMPT对局部缺血之后小胶质细胞吞噬作用，寡构成，WMI和功能结果的影响。 PHS 398/2590（修订版06/09）页面延续格式页面