Activity-Dependent Gene Expression in Human Epilepsy

我们已经开发了功能基因组学方法，以确定差异表达的基因在人类新皮质局灶性癫痫区域。我们在所有患者中发现了一小部分基因的诱导，而不管他们的癫痫病因如何。这些持续诱导的基因中的大多数属于学习和记忆中使用的经过充分研究的途径，包括MAP激酶信号传导、立即早期基因/转录以及突触发育和加强。这些基因是非常可靠的癫痫新皮层的标志物，因为它们的表达与发作间期放电频率精确相关。为了了解它们在癫痫中的作用，我们将其中一些基因定位到6层人类癫痫新皮层中的特定神经元。在这些癫痫区域内，我们发现磷酸化CREB的持续诱导和突触棘密度的相应增加。这些发现产生了一个有趣的假设，即持续的癫痫活动产生持续的MAPK信号传导和基因激活，促进结构和功能的变化，以维持慢性癫痫状态。本研究的第一个目的是将MAPK通路中的信号传导中间体与人类癫痫新皮层中突触组织的活性依赖性基因诱导和变化联系起来。第二个是使用癫痫模型在大鼠中确定MAPK信号传导对基因表达，突触变化和癫痫活动的功能重要性，以便我们可以开发新的人类抗癫痫治疗药物。

We have developed functional genomic methods to identify differentially expressed genes within focal epileptic regions of human neocortex. We discovered the induction of a small group of genes in all patients, regardless of the cause of their epilepsy. Most of these persistently-induced genes belong to a well-studied pathway used in learning and memory that includes MAP kinase signaling, immediate-early gene/transcription, and synaptic development and strengthening. These genes are extremely reliable markers of epileptic neocortex as their expression correlates precisely with interictal discharge frequency. As a means to understand their role in epilepsy, we have mapped some of these genes to specific neurons within the 6-layered human epileptic neocortex. Within these epileptic regions, we found a persistent induction of phospho-CREB and a corresponding increase in synaptic spine density. These findings generate an intriguing hypothesis that ongoing epileptic activity produces sustained MAPK signaling and gene activations that promote structural and functional changes to maintain the chronic epileptic state. The first aim in this proposal is to relate signaling intermediates in the MAPK pathway to activity-dependent gene induction and changes in synaptic organization in human epileptic neocortex. The second is to use an epileptic model in the rat to determine the functional importance of MAPK signaling on gene expression, synaptic changes, and epileptic activities so that we can develop novel human antiepileptic therapeutics.