Molecular control of aberrant adult-born granule cells in epilepsy

项目概要/摘要： 严重脑损伤（如创伤性脑损伤或癫痫持续状态）后的潜伏期， 自发性复发性癫痫发作的特征在于成年海马神经发生的变化。 深刻的形态学变化，包括肺门异位颗粒细胞和异常树突发育 (e.g.,因此，提出了癫痫发作诱导的神经发生是否 是致癫痫的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，动物模型中现有的消融策略都遭受了 无法破译机制，促进异常的成人出生的颗粒细胞（abGC），因为细胞 从电路中移除。在这个修改后的R 01应用程序中，我们将利用最近发表的工作， 我们的实验室证明，未成熟abGC中的活性调节Ca 2+和基因表达， 这是产生异常abGC和破坏海马回路所必需和充分的 导致癫痫。我们提出的工作，以确定机制，促进异常神经发生， 专注于驱动异常abGCs的基因和信号通路，以及识别神经元 异常abGC的输入。因为我们过去的工作一直是在毛果芸香碱模型的mesial 颞叶癫痫，我们将扩大这些研究，以解决异常abGC的作用，在非状态 模型，例如在受控的皮质撞击损伤后发生的癫痫。在目标1中，我们将证明， 在abGCs中hM 4D 1调节的基因表达提供了一种操纵潜在的异常基因调节的新方法。 途径，并确定我们的前2个候选基因的功能作用-Timp 3和Rrm 2-在RNA中鉴定- 测序分析在目标2中，我们将在毛果芸香碱模型中使用hM 4Di补充目标1中的工作， 鉴定野生型小鼠中与异常abGC相关的hM 3Dq活化基因和神经元输入。在 目的3，我们将在控制性皮质撞击损伤后消融或沉默abGCs，并评估其对大脑皮质的影响。 慢性癫痫的发展。这些研究预计将有助于更好地了解 促进异常abGC成熟的机制，这可能提供新的策略， 异常的新神经元，而不伤害健康的神经元。这些研究将在各种领域产生广泛的影响， 神经系统疾病，包括癫痫。

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.