Targeting aberrant neurogenesis to prevent epilepsy and associated cognitive decline

 描述（由申请人提供）：严重脑损伤后的急性癫痫发作（或癫痫持续状态，SE）通常会导致癫痫和认知障碍。海马神经发生异常后的侮辱，但成人产生的神经元在慢性癫痫发作或相关的认知缺陷的发展中的作用仍有待确定。最近，我们发现在急性癫痫发作前消融成人神经发生可降低慢性癫痫发作频率，并使癫痫相关的认知缺陷正常化。这些数据帮助我们为这项拨款提案制定了一个明确的目标：确定急性癫痫发作后神经发生消融对慢性癫痫发作和癫痫相关记忆功能的影响。我们的中心假设是成人神经发生在慢性癫痫发作和相关的记忆障碍中起着关键作用，我们的初步结果表明，靶向异常海马神经发生可能会减少复发性癫痫发作并恢复癫痫脑损伤后的认知功能。我们将在3个具体目标中验证这一假设：1）确定靶向成人神经发生以预防癫痫和相关认知缺陷的治疗窗口，2）评估异常神经发生在预防癫痫中的长期作用，3）通过NeuroD研究鉴定靶向异常神经发生的分子。目的1和2将利用巢蛋白-δ-HSV-胸苷激酶转基因小鼠遗传消融新生神经元。目标1还将使用Ascl1-CreERT2;诱导型DT-A模型消融神经发生。Aim 3将使用NeuroD条件性敲除小鼠。在所有3个目标中，我们将进行连续视频EEG记录，以测量慢性癫痫发作频率和持续时间。在目标1和2中，将进行新位置、新物体和情境依赖性恐惧条件反射测试，以测量记忆功能。概念框架和方法是创新的，因为我们将最先进的遗传和敲除小鼠技术应用于颞叶癫痫的小鼠模型，并剖析SE依赖性神经发生的潜在细胞水平机制。由于我们的长期目标是了解异常神经发生如何驱动慢性癫痫的重要分子机制，因此所提出的工作与疾病相关并且非常重要。它将推进和扩展我们对癫痫发作活动依赖的分子网络调节神经干细胞增殖、分化、存活和新生神经元成熟的基本理解，这将推进我们对基础和病理状态下神经发生的理解。拟议的研究与NIH的使命相关，因为它将使我们能够获得有关癫痫和相关合并症的基本基础的基本见解，以及获得治疗神经和精神疾病的新途径的知识。

 DESCRIPTION (provided by applicant): Acute seizures (or status epilepticus, SE) after a severe brain insult often leads to epilepsy and cognitive impairment. Aberrant hippocampal neurogenesis follows the insult but the role of adult-generated neurons in the development of chronic seizures or associated cognitive deficits remains to be determined. Recently, we found ablation of adult neurogenesis prior to acute seizures reduced chronic seizure frequency and normalized epilepsy-associated cognitive deficits. These data helped us formulate a clear objective for this grant proposal: to determine the effect of neurogenesis ablation after acute seizures in chronic seizure generation and epilepsy-associated memory function. Our central hypothesis is adult neurogenesis plays a key role in chronic seizure development and associated memory impairment, and our preliminary results suggest that targeting aberrant hippocampal neurogenesis may reduce recurrent seizures and restore cognitive function following a pro-epileptic brain insult. We will test this hypothesis in 3 specific aims: 1) To defie the therapeutic window of targeting adult neurogenesis to prevent epilepsy and associated cognitive deficits, 2) To evaluate the long-term effects of aberrant neurogenesis in preventing epilepsy, and 3) To identify molecules to target aberrant neurogenesis through studies on NeuroD. Aims 1 and 2 will utilize a Nestin-δ-HSV-thymidine kinase transgenic mouse to genetically ablate newborn neurons. Aim 1 will also use an Ascl1-CreERT2; inducible DT-A model to ablate neurogenesis. Aim 3 will use a NeuroD conditional knockout mouse. In all 3 Aims, we will perform continuous video-EEG recording to measure chronic seizure frequency and duration. In Aims 1 and 2, novel location, novel object, and context-dependent fear conditioning tests will be performed to measure memory function. The conceptual framework and approach is innovative because we will apply state-of-the-art genetic and knockout mouse techniques to a mouse model of temporal lobe epilepsy and dissect underlying cellular- level mechanisms of SE-dependent neurogenesis. As our long-term goal is to understand the molecular mechanisms important for how aberrant neurogenesis drives chronic epilepsy, the proposed work is disease- relevant and highly significant. It will advance and expand our basic understanding of seizure activity- dependent molecular networks regulating neural stem cell proliferation, differentiation, survival and maturation of newborn neurons, which will advance our understanding of neurogenesis in both basal and pathological states. The proposed study is relevant to NIH's mission as it will allow us to gain fundamental insight regarding the fundamental underpinnings of epilepsy and associated comorbidities as well as acquiring knowledge towards new avenues for treating neurological and psychiatric disorders.