Activity-Dependent Gene Expression in Human Epilepsy

我们已经开发了功能基因组方法来确定人类大脑皮层局灶性癫痫区域内差异表达的基因。我们发现在所有患者中都有一小群基因的诱导，无论他们的癫痫原因是什么。这些持续诱导的基因大多属于学习和记忆中被广泛研究的途径，包括MAP激酶信号、即刻早期基因/转录以及突触发育和加强。这些基因是癫痫新皮质极其可靠的标志物，因为它们的表达与发作间期放电频率精确相关。作为了解它们在癫痫中的作用的一种手段，我们已经将这些基因中的一些映射到6层人类癫痫新皮质中的特定神经元。在这些癫痫区域，我们发现了持续的磷酸化CREB的诱导和相应的突触棘密度的增加。这些发现产生了一个有趣的假说，即持续的癫痫活动产生持续的MAPK信号和基因激活，促进结构和功能变化，以维持慢性癫痫状态。这个建议的第一个目的是将MAPK通路中的信号中间体与人类癫痫新皮质中活性依赖的基因诱导和突触组织的变化联系起来。二是利用大鼠癫痫模型，确定MAPK信号在基因表达、突触变化和癫痫活动中的功能重要性，从而开发新的人类抗癫痫药物。

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.