RNAi Targeting of Kv3 Channels in Basal Ganglia Disease

描述(申请人提供)：帕金森病(PD)是一种以运动功能障碍为特征的神经退行性疾病。每1000名成年人中就有1人受到影响，50岁以后呈指数级上升。目前，还没有治疗帕金森病的方法可以明确地延缓疾病的进展。即使是暂时纠正症状，延长身体活动期也被认为是有价值的。 我们建议测试一种新的策略来缓解帕金森氏症的运动症状。苍白球(GP)和丘脑底核(STN)异常相关的节律活动被认为是帕金森病患者运动迟缓和震颤的基础。GP和STN神经元中的一组特定的膜电导使这种活动成为可能。我们课题组最近的工作表明，GP和STN神经元的高频猝发放电依赖于它们的电压依赖性Kv3K+通道亚基的表达。这些神经元形成含有Kv3.1和Kv3.4亚基的异构体通道。这些异构体通道在重新极化尖峰非常有效--保持它们非常短--然后在尖峰之后停用，以便下一个尖峰快速出现。从这些通道中去除Kv3.4亚基会降低通道的复极化效率，导致更低的最大放电率。因此，我们的目标是验证这一假设，即抑制GP/STN神经元中Kv3.4亚单位将显著减少病理性高频猝发放电，从而缓解PD模型和患者的症状。Kv3.4是基因治疗方法的一个很好的靶点，因为它的表达对快速尖峰神经元具有高度的特异性，而且GP/STN周围区域的非靶向神经元的放电应该不会受到影响。 我们建议使用慢病毒载体来传递小干扰RNA(SiRNA)，该小干扰RNA旨在触发GP和STN神经元中Kv3.4 mRNA的降解。拟议的具体目标将允许开发在帕金森病动物模型中检验我们的假设所需的技术。

DESCRIPTION (provided by applicant): Parkinson's disease (PD) is a neurodegenerative disorder characterized by impairment of motor function. It affects about 1 in 1000 adults, rising exponentially after the age of fifty. At present there is no treatment for PD shown to definitively attenuate disease progression. Even temporal correction of symptoms extending the period of physical mobility is considered valuable. We suggest to test a new strategy to relieve motor symptoms of the Parkinson's disease. The abnormal correlated rhythmic activity in the globus pallidus (GP) and subthalamic nucleus (STN) are believed to underlie bradykinesia and tremor of PD patients. A specific set of membrane conductances in GP and STN neurons enable such activity. Recent work by our group has shown that high frequency burst discharge in GP and STN neurons is dependent upon their expression of a combination of voltage-dependent Kv3 K+ channel subunits. These neurons form heteromeric channels containing Kv3.1 and Kv3.4 subunits. These heteromeric channels are very efficient at repolarizing spikes - keeping them very brief - and then deactivating after the spike to allow the next spike to occur quickly. Eliminating the Kv3.4 subunit from these channels diminishes the repolarizing efficiency of the channels, resulting in lower maximal discharge rates. Thus our goal is to test the hypothesis that the suppression of Kv3.4 subunit in GP/STN neurons will dramatically reduce pathological, high frequency burst discharge leading to symptomatic relief in PD models and patients. Kv3.4 is an excellent target for gene therapy approaches since its expression is highly specific for fast spiking neurons and the firing of non-targeted neurons in GP/STN surrounding areas should not be affected. We propose to use lentivirus vector to deliver small interfering RNA (siRNA) designed to trigger the degradation of Kv3.4 mRNA in GP and STN neurons. The proposed specific aims will allow development of the technology that is necessary for testing of our hypothesis in the animal models of PD.