M-Type K+ Channels: In Vivo Neuroprotective Role during Cerebrovascular Stro

M 型 K 通道：脑血管痉挛期间的体内神经保护作用

基本信息

批准号：
8484755
负责人：
Sonya Marie Bierbower
金额：
$ 5.66万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-07-01 至 2015-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8484755
关键词：
Action Potentials Animals Antiepileptic Agents Area Behavioral Behavioral Assay Biochemical Biological Assay Blood Vessels Brain Brain Edema Brain Infarction Brain region Carotid Arteries Cations Cell Death Cells Cerebrum Cessation of life Clinical Complex Cytoprotection Development Disease Dominant-Negative Mutation Dyes Encephalitis Endothelium Equilibrium Event Extravasation Filament Free Radical Formation Growth Hour Human Hypoxia Image Infarction Inflammation Inflammatory Response Injury Ipsilateral Ischemic Stroke Knock-in Mouse Lasers Learning Lesion Light Locomotion Mediating Membrane Potentials Middle Cerebral Artery Occlusion Modeling Motor Motor Skills Mus Necrosis Nervous System Trauma Neurologic Neurons Neurophysiology - biologic function Neurosciences Outcome Parietal Lobe Patients Pharmaceutical Preparations Play Potassium Channel Probability Production Reactive Oxygen Species Research Research Personnel Role Rose Bengal Rotarod Performance Test Series Severities Stroke Techniques Testing Therapeutic Intervention Thrombosis Time Tissues Training Wild Type Mouse Work acute stroke career career development cell injury cerebrovascular channel blockers design disability drug development flupirtine improved in vivo in vivo Model innovation insight middle cerebral artery morris water maze mouse model neuronal excitability neuroprotection novel novel therapeutic intervention novel therapeutics post stroke research study response skills voltage

项目摘要

DESCRIPTION (provided by applicant): Stroke is the third leading cause of human death in the USA and remains the focus of efforts to define the pathophysiologic mechanisms leading to tissue damage. Neuronal damage and cell loss occurs in numerous brain regions after strokes, thus providing a highly-relevant context for study. This project investigates neuroprotection during ischemic stroke through "M-channels" which are critical K+ channels that stabilize resting potentials by counterbalancing the depolarizing effects of excitatory cation currents. Produced by combinations of KCNQ2-5 subunits, voltage-gated M channels play critical roles in control of neuronal excitability, and action potential firing. We have previously shown that most M-type channels to be up- regulated by reactive oxygen species (ROS), molecules commonly produced during and after ischemic cerebrovascular stroke. This study hypothesizes that M current-mediated neuronal silencing has a neuroprotective role by increasing the open-probability of KCNQ channels, thus decreasing neuronal activity and prolonging activation of cellular cascades resulting in cell death. Two in vivo mouse models are used and the first involves a cerebral infarct within the parietal cortex produced by laser-controlled photothrombosis. When the photo-sensitizing dye, Rose Bengal, is irradiated by laser light, free-radical formation occurs causing endothelium damage, leakage of vascular contents into the parenchyma and vascular thrombosis. The second in vivo model is the middle cerebral artery occlusion (MCAo), in which a filament is introduced non-invasively into the MCA via the carotid artery. The MCAo model produces a catastrophic stroke in the ipsilateral hemisphere, with correspondingly pronounced cerebral deficits. The M-current activity will be pharmacologically altered in both mouse models using the M-channel openers, retigabine (RTG) and flupirtine, and the blocker, XE991, with drug application at various time points post-stroke. Additionally, dominant- negative KCNQ3 knock-in mice will be used in both models to confirm a specific M-channel mechanism. Finally, behavioral assays designed to distinguish degrees of injury and neural function will be used to delineate minute changes in function due to channel activation or blockage. Motor and co-ordination deficits will be assayed with the balance beam, ladder dexterity, open-field locomotion and accelerating rotarod tests. Learning deficits will be assayed using the Morris water maze. Thus, this study uses two strong and exciting stroke models, which may provide novel modes of therapeutic intervention for reducing neuronal damage caused during commonly-occurring ischemic attacks, by modulating the activity of M-type K+ channels.

描述（由申请人提供）：中风是美国人类死亡的第三主要原因，并且仍然是定义导致组织损害的病理生理机制的努力的重点。中风后许多大脑区域发生神经元损伤和细胞丧失，从而为研究提供了高度相关的背景。该项目通过“ M通道”调查了缺血性中风期间的神经保护作用，这是关键的K+通道，通过平衡兴奋性阳离子电流的去极化作用来稳定静息电位。通过KCNQ2-5亚基的组合产生的电压门控M通道在控制神经元兴奋性和动作电势射击方面起着关键作用。我们先前已经表明，大多数由反应性氧（ROS）上调节的大多数M型通道，通常在缺血性脑脑中和之后产生的分子。这项研究假设M电流介导的神经元沉默通过增加KCNQ通道的开放性而具有神经保护作用，从而降低了神经元活性并延长细胞级联反应导致细胞死亡。使用了两个体内小鼠模型，首先涉及激光控制的光栓塞产生的甲状腺皮质内的脑梗塞。当光敏染料（玫瑰孟加拉）被激光光照射时，自由基形成会导致内皮损伤，血管含量泄漏到实质中和血管血栓形成。第二个体内模型是脑动脉闭塞（MCAO），其中细丝通过颈动脉非侵入性地引入MCA。 MCAO模型在同侧半球中产生灾难性的中风，具有相应的大脑缺陷。在两种小鼠模型中，使用M通道开瓶器（RTG）（RTG）和Flupirtine以及Blocker XE991在两种小鼠模型中都会改变M-电流活性。另外，在两种模型中都将使用显性 - 负KCNQ3敲入小鼠来确认特定的M通道机制。最后，旨在区分损伤程度和神经功能程度的行为分析将用于描述由于通道激活或阻塞而导致功能的微小变化。电动机和协调不足将通过平衡梁，梯子敏捷，开放式运动和加速旋转rot测试来测定。学习缺陷将使用莫里斯水迷宫进行测定。因此，这项研究使用了两个强烈而令人兴奋的中风模型，这些模型可以通过调节M型K+通道的活性来提供新型的治疗干预模式，以减少常见的缺血性攻击期间造成的神经元损伤。