ARX related Interneuron dysfunction and intractable pediatric epilepsy

描述（由申请人提供）：早期癫痫性脑病是一组以难治性癫痫发作、发育不良、6岁前发病为特征的综合征。作为一名专门研究儿童癫痫的儿童神经学家，我花了很多临床时间为患有这些疾病的孩子的家庭提供咨询。我发现这些对话令人沮丧，因为我告诉这些家庭，我们的治疗方法不是针对这些疾病设计的，指导诊断和治疗的基础研究也很少。迫切需要对早期顽固性癫痫进行进一步的研究。如果要在诊断和治疗方面取得进展，开发模型来研究这些综合征是必不可少的。最近，一种发育转录因子——马栗子相关同源盒基因（ARX）的突变已被证明可导致x连锁婴儿痉挛综合征和其他早期癫痫性脑病。我们的实验表明，中间神经元中Arx的选择性基因缺失（Arx CKO）导致gaba能中间神经元的异常迁移、脑电图活动改变和自发性癫痫发作。这些数据使我们假设，在条件Arx小鼠中，早期中间神经元的丧失改变了正常网络功能的发展，导致顽固性癫痫发作和早期癫痫性脑病的认知功能障碍。这一建议既制定了实验来检查中间神经元功能障碍如何导致癫痫发作和脑病的潜在病理生理过程，也为我提供了培训机会，以促进我作为一名独立研究者的职业过渡。为了研究Arx丢失如何导致癫痫发作和智力迟钝，我首先建议使用电压敏感染料成像技术来确定电路水平功能障碍的程度。接下来，我们将记录和比较对照小鼠和Arx CKO突变小鼠在皮层和海马节律期间的脑电图和单单位活动的发展，以确定节律是如何中断的以及哪些中间神经元参与其中。这些研究将确定中断神经元间发育是否会改变束缚认知过程的正常节律。最后，我们将使用一系列行为技术测试小鼠的认知功能，以提供将回路和网络水平的功能障碍与小鼠的认知缺陷联系起来的证据。除了提议的实验之外，我还制定了一个计划，帮助我在费城儿童医院和宾夕法尼亚大学工作时培养过渡到独立所需的技能。从这些研究中，我将学习两个技巧，并在我未来的工作中实施。这些研究也将奠定一个模型的基础，用于理解神经元间发育的改变是如何导致早期癫痫性脑病的。

DESCRIPTION (provided by applicant): The early epileptic encephalopathies are a group of syndromes characterized by intractable seizures, poor developmental outcome, and onset before six years of age. As a child neurologist specializing in pediatric epilepsy, I spend much of my clinical time counseling families whose children have these conditions. I find the conversations to be frustrating as I inform the families that our treatments are not designed for these diseases and little basic research exists to guide diagnosis and treatment. There is a pressing need for further research into the early intractable epilepsies. Developing models to study these syndromes is essential if advances in diagnosis and treatment are to be made. Recently, mutations in the aristaless-related homeobox gene (ARX), a developmental transcription factor, have been shown to cause X-linked infantile spasms syndrome and other early epileptic encephalopathies. Our experiments have shown that selective genetic deletion of Arx in interneurons (Arx CKO) results in abnormal migration of GABAergic interneurons, altered EEG activity, and spontaneous seizures. These data lead us to hypothesize that early loss of interneurons, in conditional Arx mice, alters the development of normal network function leading to intractable seizures and cognitive dysfunction modeling the early epileptic encephalopathies. This proposal both formulates experiments to examine the underlying pathophysiological processes of how interneuron dysfunction leads to seizures and encephalopathy as well as develops training opportunities to facilitate my transition to a career as an independent investigator. To study how Arx loss leads to seizures and mental retardation I first propose to determine the extent of circuit level dysfunction using a voltage sensitive dye imaging technique. Next, we will record and compare the development of control and Arx CKO mutant mice EEG and single unit activity during cortical and hippocampal rhythms to determine how rhythms are interrupted and which interneurons are involved. These studies will ascertain if interrupting interneuronal development alters the normal rhythms that bind cognitive processes. Finally, we will test the cognitive function of the mice, using a battery of behavioral techniques, to provide evidence linking circuit and network level dysfunction to the cognitive deficits of the mice. In addition to the proposed experiments, I have created a plan to help develop the skills needed for my transition to independence while working at the Children's Hospital of Philadelphia and the University of Pennsylvania. From these studies I will learn two techniques to implement in my future work. These studies will also set the foundation of a model to be used to understand how alterations in interneuronal development lead to an early epileptic encephalopathy.