Gene Therapy for Treatment of Epilepsy

描述(申请人提供)：尽管在癫痫治疗方面取得了许多进展，但难于药物干预的癫痫发作仍然是癫痫患者发病率和残疾的重要原因。涉及癫痫患者的纵向研究表明，许多患者的癫痫发作频率和严重程度都有所减少，但无论是手术治疗还是内科治疗的患者，尽管接受了治疗，但记忆功能往往呈进行性下降。因此，控制癫痫发作的新方法是必要的。癫痫发作倾向的增加是由神经元兴奋性异常引起的。电压门控离子通道在控制神经元内在兴奋性方面起着重要作用，许多离子通道与人类和动物癫痫综合征有关。其中一类电压门控离子通道是超极化激活的环核苷酸门控(HCN)通道，它介导阳离子电流Ih。已发现四个密切相关的基因(Hcn1-4)编码不同的通道亚单位蛋白(HCN1-4)；这些通道与全身性和局灶性癫痫有关。Hcn2基因的全局缺失可能通过增加丘脑皮质神经元中钙通道的爆发，导致小鼠癫痫失神。我们最近鉴定了一种新的自发的小鼠神经学突变体，Aapthetic，它患有缺失性癫痫，原因是在HCN2基因上插入了一个四个碱基对，扰乱了HCN2蛋白的表达。由于丘脑皮质神经元中hcn2的丢失产生钙通道介导的爆发，从而导致小鼠失神发作，我们假设病毒过表达hcn2在丘脑皮质神经元中将恢复正常的h通道功能，并减少癫痫、麻木小鼠的癫痫发作。我们将利用生理学、细胞生物学和生物化学技术来解决以下具体目标：1)确定病毒过表达在迟钝小鼠的丘脑皮质神经元是否可以恢复Hcn2蛋白的表达并逆转ih的缺陷；2)确定病毒过表达的丘脑皮质神经元是否可以减少迟钝小鼠的癫痫发作。 公共卫生相关性：在公共卫生方面，尽管有许多新的内科和外科治疗，难治性癫痫发作仍然是导致癫痫患者残疾的一个重要原因。这项工作的目的是探索利用病毒向神经元传递特定离子通道基因是否可以有效逆转癫痫脑内离子通道缺陷和防止癫痫发作，最终目的是探索这一工具作为一种治疗难治性癫痫的新方法。

DESCRIPTION (provided by applicant): Despite numerous advances in epilepsy therapeutics, seizures refractory to medical intervention remain a significant cause of morbidity and disability in patients with epilepsy. Longitudinal studies involving patients with epilepsy have shown reduction of frequency and severity of seizures in many patients, but both surgically and medically treated patients often demonstrate a progressive decline in memory function despite treatment. As such novel approaches to controlling seizures in epilepsy are warranted. Increased seizure propensity in epilepsy is caused by abnormal neuronal excitability. Voltage gated ion channels play an important role in controlling intrinsic neuronal excitability, and many have been implicated in human and animal epilepsy syndromes. One such class of voltage-gated ion channels is the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel, which mediates the cationic current, Ih. Four closely related genes (Hcn1-4) coding for distinct channel subunit proteins (HCN1-4) have been identified; these channels have been implicated in both generalized and focal epilepsies. Global deletion of Hcn2 causes absence epilepsy in mice, likely by increasing calcium channel bursting in thalamocortical neurons. We have recently characterized a novel spontaneous mouse neurological mutant, apathetic, which has absence epilepsy owing to a four base pair insertion in the Hcn2 gene that disrupts HCN2 protein expression. Because loss of HCN2 in thalamocortical neurons produces calcium channel-mediated bursting that leads to absence seizures in mice, we hypothesize that viral overexpression of HCN2 in thalamocortical neurons will restore normal h channel function and reduce seizures in the epileptic, apathetic mice. We will utilize physiological, cell biological and biochemical techniques to address the following specific aims: 1) To determine whether viral overexpression of HCN2 in thalamocortical neurons of apathetic mice can restore HCN2 protein expression and reverse the deficit in Ih, and 2) to determine whether viral overexpression of HCN2 in thalamocortical neurons reduce seizures in apathetic mice. PUBLIC HEALTH RELEVANCE: With respect to public health, despite numerous new medical and surgical treatments, refractory seizures remain a significant cause of disability in patients with epilepsy. The purpose of this work is to explore whether gene therapy utilizing viral delivery of specific ion channel genes to neurons can effectively reverse ion channel deficits and prevent seizures in epileptic brain, with the ultimate goal of exploring this tool as a novel therapy for medically refractory epilepsy.