Developing a drug-inducible gene therapy for temporal lobe epilepsy

美国有300万癫痫患者。这项研究旨在开发一种一流的药物- 针对最常见形式的局灶性癫痫、颞叶癫痫（TLE）的诱导基因疗法。tle 影响了50万美国人，然而，尽管这个问题的规模，TLE的医学治疗失败， 三分之一的病人。显然，对于无副作用的治疗存在大量未满足的临床需求。 这些研究的指导性假设是TLE是一种基于回路的疾病， 开发针对这些回路的下一代基因疗法。关键技术进步 为解决这一假设所做的工作包括：1）开发新的TLE动物模型， 适合药物筛选的自发性癫痫发作特征; 2）绘制癫痫回路 使用活性依赖性启动子;以及3）开发靶向 具体电路。人们发现，电刺激特定品系的小鼠（VGAT-Cre） 足以引发边缘癫痫为了将该模型扩展到其他品系的小鼠， 刺激与化学惊厥剂红藻氨酸组合。这种混合方法有效地 在常用的小鼠品系如C57B1/6中引发自发性癫痫发作。重要的是 混合方法为使用TRAP2菌株的研究打开了大门，该菌株已被证明对电路有用。 制图研究。药物诱导基因疗法使用公认的多西环素（Dox） 规范系统。技术上的挑战是将这个系统固定化，使其适合病毒载体， 在没有诱导物（泄漏）的情况下减少基因表达，并开发启动子工具包， 靶向神经元亚型。我们的目标是开发一个Dox-On系统， 癫痫发作和可能的副作用可以通过降低Dox剂量来减少。减少泄漏， 背景水平是一个重要的安全特征，尚未纳入任何FDA批准的 基因治疗目前许多抗癫痫药物的作用机制是减少癫痫发作， 兴奋性神经元的活性或增强抑制性神经元的活性。通过开发基因 选择性靶向这些类型的神经元的治疗，拟议的研究将比较这两种 接近。这些疗法的关键指标是显示它们减少自发性癫痫发作频率 50%，目标是癫痫回路中的特定节点。疗效研究将采用严格的临床前 具有盲法、再现性和靶点参与的研究设计。为使这一方案取得成功， 研究是癫痫动物模型基础研究临床转化的丰富环境。

There are 3 million Americans with epilepsy. This research aims to develop a first-in-class drug- inducible gene therapy for the most common form of focal epilepsy, temporal lobe epilepsy (TLE). TLE affects half a million Americans, yet despite the size of this problem, medical treatment of TLE fails in a third of these patients. Clearly there is a large unmet clinical need for a treatment without side effects. The guiding hypothesis of these studies is that TLE is a circuit-based disease, requiring the development of next-generation gene therapies that target these circuits. Key technological advances made to address this hypothesis include: 1) development of novel animal models of TLE with spontaneous seizure characteristics that are amenable to drug screening; 2) mapping epileptic circuits using activity-dependent promoters; and 3) development of drug-inducible gene therapies that target specific circuits. It was discovered that electrical stimulation of a specific strain of mouse (VGAT-Cre) was sufficient to trigger limbic epilepsy. To extend the model to other strains of mice, electrical stimulation was combined with a chemoconvulsant, kainic acid. This hybrid approach effectively triggered spontaneous seizures in commonly used mouse strains, such as C57Bl/6. Importantly, the hybrid approach opened the door for studies using the TRAP2 strain, which has proven useful for circuit mapping studies. The drug-inducible gene therapy uses the well-established doxycycline (Dox) regulated system. The technological challenges were to miniaturize this system so it fits in viral vectors, reduce gene expression in the absence of the inducer (leak), and develop a toolkit of promoters to target neuronal subtypes. The goal is to develop a Dox-On system where Dox administration reduces seizures and that possible side effects can be reduced by lowering the Dox dose. Reducing leak to background levels is an important safety feature that has yet to be incorporated in any FDA-approved gene therapy. The mechanisms of action of many current antiseizure drugs are to either reduce the activity of excitatory neurons or enhance the activity of inhibitory neurons. By developing gene therapies that selectively target these types of neurons, the proposed studies will compare these two approaches. Key metrics for these therapies are to show they reduce spontaneous seizure frequency by 50% and target specific nodes in the epileptic circuit. Efficacy studies will use rigorous preclinical study designs with blinding, reproducibility, and target engagement. Contributing to the success of this study is a rich environment for clinical translation of basic research in animal models of epilepsy.