Interneurons and Epilepsy in Dlx1 Mutant Mice

描述（由申请人提供）：抑制性中间神经元合成GABA，并在中枢神经系统中发挥关键调节作用。最近的观察表明，这些interneurons的发展需要一个家庭的Dlx转录因子。在我们实验室的研究中（Cobos et al. 2005），证明缺乏Dlx 1的小鼠逐渐丧失皮质和海马中间神经元的一个亚类，导致突触抑制减少和癫痫。这种新的神经元缺陷的迟发性癫痫模型提供了一个独特的机会来精确定义神经元在癫痫发生中的作用，并最终测试治疗干预措施来中断或废除这一过程。为了响应最近的NINDS“基准”，我们在这里提出的实验，将检查Dlx 1缺陷（和随后的interneuron损失）如何改变网络的兴奋性，并测试一个潜在的治疗干预使用GABA祖细胞。技术将涉及使用急性脑切片保持在体外，和应用可视化膜片钳方法来研究海马中间神经元及其相关电路的生理功能。还将应用视频脑电图监测和细胞移植技术。提出了三个具体的目标：（i）确定Dlx1是否需要中间神经元的功能，（ii）确定是否突触输入到幸存的中间神经元在Dlx1突变小鼠被破坏，和（iii）确定GABA祖细胞移植物是否减少癫痫发作活动在Dlx1突变小鼠。我们的研究结果有望提供有关中间神经元在癫痫中的作用的关键信息，并可能直接证明GABA祖细胞治疗癫痫发作的潜力。 公共卫生相关性：癫痫是一种常见的神经系统疾病，困扰着近300万美国人。海马和皮层回路中抑制性突触传递的丢失或减少是导致癫痫出现的一个潜在机制。使用缺乏抑制性神经细胞的小鼠突变体和细胞移植策略来产生新的抑制性神经细胞，我们将研究癫痫的潜在机制和潜在的治疗方法。

DESCRIPTION (provided by applicant): Inhibitory interneurons synthesize GABA and play a critical regulatory role in the central nervous system. Recent observations suggest that development of these interneurons requires a family of Dlx transcription factors. In studies from our laboratory (Cobos et al. 2005), it was demonstrated that mice lacking Dlx1 progressively lose a sub-class of cortical and hippocampal interneurons resulting in reduced synaptic inhibition and epilepsy. This novel model of interneuron-deficient, late-onset epilepsy offers a unique opportunity to precisely define the role of interneurons in epileptogenesis, and ultimately test therapeutic interventions to interrupt or abrogate this process. In response to recent NINDS "benchmarks", we here propose experiments that will examine how Dlx1 deficiency (and subsequent interneuron loss) alters network excitability, and test a potential therapeutic intervention using GABA progenitor cells. Techniques will involve use of acute brain slices maintained in vitro, and application of visualized patch clamp methods to study the physiological function of hippocampal interneurons and their associated circuits. Video-EEG monitoring and cell grafting techniques will also be applied. Three specific aims are proposed: (i) determine whether Dlx1 is required for interneuron function, (ii) determine whether synaptic input to surviving interneurons is disrupted in Dlx1 mutant mice, and (iii) determine whether GABA progenitor cell grafts reduce seizure activity in Dlx1 mutant mice. Our results promise to provide critical information about the role of interneurons in epilepsy and may provide a direct demonstration of the potential for GABA progenitor cells to treat seizures. PUBLIC HEALTH RELEVANCE: Epilepsy is a common neurological disorder afflicting nearly 3 million Americans. Loss or reduction of inhibitory synaptic transmission in hippocampal and cortical circuits is one potential mechanism resulting in the emergence of epilepsy. Using a mouse mutant lacking inhibitory nerve cells, and a cell grafting strategy to generate new inhibitory nerve cells, we will examine the mechanisms underlying epilepsy and a potential treatment.