A novel target for the treatment of temporal lobe epilepsy

治疗颞叶癫痫的新靶点

• 批准号: 9087344
• 负责人: Andrew P Escayg
• 金额: $ 46.58万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9087344
• 关键词: Affect; Anxiety; Behavior; Behavioral; C57BL/6 Mouse; Clinical; Control Groups; Development; Disease; Dose; Electroencephalography; Encephalopathies; Epilepsy; Etiology; Excision; Exhibits; Febrile Convulsions; Frequencies; Gene Family; Generations; Genes; Genetic; Health; Hippocampus (Brain); Hour; Human; Individual; Injection of therapeutic agent; Kainic Acid; Knockout Mice; Laboratories; Learning; Longevity; Measurement; Memory; Modeling; Monitor; Morphology; Mus; Mutation; Neuraxis; Neurons; Operative Surgical Procedures; Patient observation; Patients; Play; Procedures; Reagent; Recurrence; Refractory; Reporting; Resistance; Role; SCN8A gene; Seizures; Severities; Site; Slice; Sodium; Sodium Channel; Syndrome; Temporal Lobe Epilepsy; Testing; adeno-associated viral vector; alternative treatment; base; biophysical properties; clinically relevant; effective therapy; gain of function mutation; hippocampal sclerosis; improved; insight; knock-down; male; mammalian genome; mouse model; mutant; mutant mouse model; nervous system disorder; neuron loss; neuronal excitability; neuropsychological; novel; prevent; segregation; small hairpin RNA; translational study; treatment strategy; voltage

 DESCRIPTION (provided by applicant): Epilepsy is a common neurological disorder that affects 50 million people worldwide. Approximately 30% of epileptic patients have treatment resistant (refractory) seizures, thereby presenting a major clinical challenge and burden. The most common form of refractory epilepsy is mesial temporal lobe epilepsy (MTLE), characterized by spontaneous seizures, neuropsychological deficits, and hippocampal sclerosis. At present, surgical resection of the epilepsy focus is the best treatment strategy for this disorder; however, this procedure is only used in a subset of cases. Consequently, there is an urgent need to develop alternative treatments. Mutations in the voltage-gated sodium channels (VGSCs) SCN1A, SCN2A, and SCN3A are associated with several epilepsy subtypes including Dravet syndrome (DS) and genetic epilepsy with febrile seizures plus (GEFS+). Gain of function mutations in the VGSC SCN8A have recently identified in individuals with epileptic encephalopathies. However, our laboratory has demonstrated that mice with Scn8a mutations that reduce channel activity or expression are more resistant to induced seizures when compared to their wild-type littermates. In addition, we were able to dramatically ameliorate seizure severity and restore normal lifespans to Scn1a mutants that model DS and GEFS+ by either co-segregation of an Scn8a mutation or hippocampal knockdown of Scn8a expression. Since the hippocampus is the major site of seizure generation and morphological changes in MTLE, we hypothesize that selective reduction of SCN8A expression in the hippocampus will provide an effective strategy for the treatment of MTLE. We will test this hypothesis with three specific aims. In Aim 1, we will establish the effect on spontaneous seizure frequency and severity of reducing hippocampal Scn8a expression in the widely used intra-hippocampal kainic acid mouse model of MTLE. Reduced Scn8a expression will be achieved by hippocampal injection of an adeno-associated viral vector expressing a short hairpin RNA against Scn8a (AAV-3). Seizure activity will be monitored in AAV-3 treated mice using continuous video/EEG analysis and will be compared to control mice injected with a scrambled construct (AAV-GFP). In Aim 2, we will determine if hippocampal reduction of Scn8a expression could also prevent or ameliorate the changes in behavior and hippocampal morphology and that are observed in this model of MTLE. Finally, in Aim 3, we compare the biophysical properties of hippocampal slices from the AAV-3 and AAV-GFP treated mice in order to directly examine neuronal excitability. We will also test if partial pharmacological block of Nav1.6, using novel compounds, can reduce seizure-like bursting activity in hippocampal slices from the MTLE mouse model, and we will explore the contribution of the different VGSCs to the development of MTLE. This clinically relevant proposal will provide important insight into the feasibility of targeting SCN8A as a treatment for MTLE, and more broadly, for other forms of refractory epilepsy.

 描述（由适用提供）：癫痫是一种常见的神经系统疾病，影响了全球5000万人。大约30％的癫痫患者患有耐药性（难治性）癫痫发作，从而提出了重大的临床挑战和伯嫩。难治性癫痫的最常见形式是介体临时叶癫痫（MTLE），其特征是由自发性癫痫发作，神经心理学缺陷和海马硬化赞助。目前，癫痫重点的手术切除是该疾病的最佳治疗策略。但是，此过程仅在一部分情况下使用。因此，迫切需要开发替代治疗方法。电压门控钠通道（VGSC），SCN1A，SCN2A和SCN3A中的突变与几种癫痫亚型（包括Dravet综合征（DS）和遗传性癫痫病，具有高发作性癫痫发作加上（GEFS+））。 VGSC SCN8A中功能突变的增益最近在癫痫性脑病患者中鉴定出来。但是，我们的实验室表明，与野生型同窝仔相比，使用SCN8A突变减少通道活性或表达的小鼠对诱导的癫痫发作更具耐药性。此外，我们能够通过对SCN8A突变的共隔离或SCN8A表达的海马敲低来显着改善癫痫发作的严重程度，并恢复对DS和GEFS+建模的正常寿命。由于海马是癫痫发作产生和形态变化的主要部位，因此我们假设在海马中选择性降低SCN8A表达将为治疗MTLE提供有效的策略。我们将以三个特定的目标检验这一假设。在AIM 1中，我们将建立对降低海马SCN8A表达在广泛使用的海马内海马内海藻酸小鼠MTLE模型中的影响的影响。通过海马注射腺相关病毒载体，表达针对SCN8A的短发夹RNA（AAV-3），SCN8A表达降低将实现。使用连续的视频/EEG分析，将在AAV-3处理的小鼠中监测癫痫发作活动，并将其与注射炒构建体（AAV-GFP）的对照小鼠进行比较。在AIM 2中，我们将确定SCN8A表达的海马还原是否也可以预防或改善行为和海马形态的变化，并且在这种MTLE模型中观察到。最后，在AIM 3中，我们比较了来自AAV-3和AAV-GFP处理的小鼠的海马切片的生物物理特性，以直接检查神经元令人兴奋。我们还将测试使用新型化合物的NAV1.6的部分药理学块是否可以减少MTLE小鼠模型中海马切片中的癫痫发作样爆发活性，我们将探索不同VGSC对MTLE开发的不同VGSC的贡献。该临床上相关的建议将为靶向SCN8A作为MTLE的治疗以及更广泛的其他形式的难治性癫痫的可行性提供重要的见解。