GABA-A Receptor Rescue as a Neuroprotective Strategy in Cerebral Ischemia

GABA-A 受体拯救作为脑缺血的神经保护策略

基本信息

批准号：
7501939
负责人：
Paco S Herson
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：
2007
资助国家：
美国
起止时间：
2007-09-30 至 2012-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7501939
关键词：
Adverse effects Allopregnanolone Animals Anoxia Brain region Cell Death Cell Survival Cells Cerebellar cortex structure Cerebellum Cerebral Ischemia Cessation of life Data Event Excitatory Amino Acid Antagonists GABA-A Receptor Glucose Glutamate Receptor Glutamates Heart Arrest Hippocampus (Brain)Human In Vitro Injection of therapeutic agent Intervention Ischemia Memory Methods Modeling Molecular Motor Mus Neurologic Neurological outcome Neurons Outcome Output Oxygen Pathway interactions Phosphorylation Proteins Purkinje Cells Rate Research Role Synapses Testing Time United States deprivation excitotoxicity gamma-Aminobutyric Acid improved in vivo inhibitor/antagonist loss of function mortality motor deficit multicatalytic endopeptidase complex neuronal survival neuroprotection novel novel strategies prevent protein function receptor receptor function response voltage clamp

项目摘要

DESCRIPTION (provided by applicant): Each year approximately 500,000 people suffer from cardiac arrest in the United States, an event associated with poor neurological outcome. Despite intense research over the past 50 years, there are no pharmacological interventions that have proven successful in improving survival and outcome. A hallmark of ischemia-induced neuronal death is excessive release of glutamate leading to excitotoxicity. Unfortunately, glutamate antagonists have proven unsuccessful in humans, predominantly due to side effects. The logical alternative approach would be to apply compounds that activate GABA-A receptors (GABA-A R) in order to counteract excessive glutamate release and excitotoxicity. Interestingly, GABAergic compounds have yielded disappointingly variable results. Recent data has demonstrated that ischemia results in a rapid loss of GABA-A R protein, indicating that the ischemia-induced decrease in GABA-A R protein may cause a decrease in efficacy of GABA-potentiating compounds. Therefore, a treatment that stabilizes GABA-A R protein and function during an ischemic event is an appealing and exciting new approach to neuroprotection. In order to obtain electrophysiological recordings of neuronal GABA-A R function following ischemia, we have developed a cerebellar neuronal culture model. We will use a combination of methods, most notably whole-cell voltage- clamp recordings of synaptic (mIPSCs) and total GABA-A R activity (Current in response to exogenously applied saturating GABA) to confirm and extend upon our preliminary observation that ischemia causes a reduction in functional GABA-A Rs and importantly that ALLO prevents this ischemia-induced loss of function. This RO1 application will test four specific hypotheses 1) that ALLO prevents ischemia-induced reduction in functional GABA-A R, thereby protecting PCs from ischemia. 2) ALLO prevents ischemia-induced reduction in GABA-A R function by maintaining PKC activity and phosphorylation of GABA-A Rs during ischemia. 3) ALLO stabilizes GABA-A R protein during ischemia by preventing proteosome-dependent degradation of GABA-A receptor protein following ischemia and finally 4) that the ALLO-induced protection of GABA-A R function occurs in intact animals exposed to global ischemia (cardiac arrest). Our findings will begin to elucidate the cellular mechanisms of ALLO neuroprotection of PCs and determine molecular pathways that may represent novel targets for neuroprotection.

描述（由申请人提供）：在美国，每年约有 500,000 人遭受心脏骤停，这是一种与神经系统不良后果相关的事件。尽管过去 50 年进行了大量研究，但尚无药物干预措施被证明可以成功改善生存和预后。缺血引起的神经元死亡的一个标志是谷氨酸的过度释放，导致兴奋性毒性。不幸的是，谷氨酸拮抗剂已被证明在人类中不成功，主要是由于副作用。合理的替代方法是应用激活 GABA-A 受体 (GABA-A R) 的化合物，以抵消过量的谷氨酸释放和兴奋性毒性。有趣的是，GABA能化合物产生了令人失望的多变结果。最近的数据表明，缺血导致GABA-A R 蛋白快速丢失，表明缺血诱导的GABA-A R 蛋白减少可能导致GABA 增强化合物的功效降低。因此，在缺血事件期间稳定 GABA-A R 蛋白和功能的治疗是一种有吸引力且令人兴奋的神经保护新方法。为了获得缺血后神经元 GABA-A R 功能的电生理记录，我们开发了小脑神经元培养模型。我们将使用多种方法的组合，最显着的是突触 (mIPSC) 的全细胞电压钳记录和总 GABA-A R 活性（响应外源施加的饱和 GABA 的电流）来确认和扩展我们的初步观察，即缺血导致功能性 GABA-A R 的减少，重要的是 ALLO 可以防止这种缺血引起的功能丧失。该 RO1 应用将测试四个具体假设 1) ALLO 可以防止缺血引起的功能性 GABA-A R 减少，从而保护 PC 免受缺血。 2) ALLO 通过在缺血期间维持 PKC 活性和 GABA-A R 的磷酸化来防止缺血引起的 GABA-A R 功能降低。 3) ALLO 通过防止缺血后 GABA-A 受体蛋白的蛋白酶体依赖性降解来稳定缺血期间的 GABA-A R 蛋白，最后 4) ALLO 诱导的 GABA-A R 功能保护发生在暴露于整体缺血的完整动物中（心脏停搏）。我们的研究结果将开始阐明 ALLO 对 PC 神经保护的细胞机制，并确定可能代表神经保护新靶点的分子途径。