Molecular control of aberrant adult-born granule cells in epilepsy

项目摘要/摘要： 严重脑损伤后的潜伏期，如创伤性脑损伤或癫痫持续状态，并在 自发性反复发作，以成年后海马神经发生的改变为特征。 包括肺门异位颗粒细胞和树突发育异常在内的深刻的形态变化 (例如，肺门基底树突起)，因此提出了一个问题，即癫痫是否诱导神经发生 会导致癫痫。我们过去在急性癫痫发作之前或之后消融成人神经发生的工作表明- 新神经元的癫痫作用，然而在动物模型中现有的消融策略都受到了 无法破译促进异常成人出生颗粒细胞(AbGC)的机制，因为这些细胞 从电路中移除。在这个修订的R01应用程序中，我们将利用最近发布的来自 我们的实验室证明，未成熟abGC中的活动调节钙离子和基因表达，这是 产生异常abGC和破坏海马神经回路的必要条件和充分条件 导致癫痫。我们建议开展工作以确定促进异常神经发生的机制， 重点关注驱动异常abGC的基因和信号通路，以及识别神经元 对异常的abGC的输入。因为我们过去的工作一直是在皮洛卡品模型的梅赛尔 颞叶癫痫，我们将扩大这些研究，以解决异常abGC在非状态中的作用 模型，如癫痫发生后，受控皮质撞击损伤。在目标1中，我们将证明 HM4Di调控的abGC基因表达为调控潜在的异常基因调控提供了新的途径 途径并定义我们在RNA中发现的前两个候选基因-TIMP3和Rrm2-的功能作用。 测序分析。在目标2中，我们将在匹罗卡品模型中使用hM4Di来补充目标1中的工作，并 鉴定与野生型小鼠异常abGC相关的hM3Dq激活基因和神经元输入。在……里面 目的3，我们将消融或沉默受控皮质撞击伤后的abGC，并评估其对 慢性癫痫的发展。这些研究预计将为我们提供更好的理解 促进ABGC异常成熟的机制，这可能提供特定靶点的新策略 不正常的新神经元，而不是健康的神经元。这些研究将广泛影响各种不同的 包括癫痫在内的神经系统疾病。

Project Summary/Abstract: The latent period after a severe brain insult such as traumatic brain injury or status epilepticus, and before the onset of spontaneous recurrent seizures, is characterized by changes in adult hippocampal neurogenesis. Profound morphological changes, including hilar ectopic granule cells and abnormal dendritic development (e.g., hilar basal dendrites) is observed, therefore raising the question whether seizure- induced neurogenesis is epileptogenic. Our past work of ablating adult neurogenesis before or after acute seizures has shown a pro- epileptic role of new neurons, however existing ablation strategies in animal models have all suffered from an inability to decipher the mechanisms that promote aberrant adult-born granule cells (abGCs) because the cells are removed from the circuit. In this revised R01 application, we will capitalize on recently published work from our laboratory demonstrating that activity in immature abGCs regulates Ca2+ and gene expression which is necessary and sufficient for the production of aberrant abGCs and disruption of the hippocampal circuitry leading to epilepsy. We propose work to determine the mechanisms that promote aberrant neurogenesis, focusing on the genes and signaling pathways that drive aberrant abGCs as well as identifying the neuronal inputs to the aberrant abGCs. Because our past work has always been in the pilocarpine model of mesial temporal lobe epilepsy, we will expand these studies to address the role of aberrant abGCs in a non-status model, such as epilepsy that occurs after controlled cortical impact injury. In Aim 1, we will demonstrate that hM4Di-regulated gene expression in abGCs offers a new way to manipulate potential aberrant gene regulatory pathways and define the functional role of our top 2 candidate genes – Timp3 and Rrm2 - identified in RNA- sequencing analysis. In Aim 2, we will complement the work in Aim 1 using hM4Di in the pilocarpine model and identify the hM3Dq activated genes and neuronal inputs associated with aberrant abGCs in wild-type mice. In Aim 3, we will ablate or silence abGCs after controlled cortical impact injury and evaluate the impact on the development of chronic seizures. Together these studies are expected to provide a greater understanding of the mechanisms that promote aberrant abGC maturation, which may offer new strategies to specifically target abnormal new neurons while sparing healthy neurons. These studies would be broadly impactful in a variety of neurological disorders including epilepsy.