Genetic Silencing of Striatal CaV1.3 Calcium Channels as a Potent Antidyskinetic Therapy for PD

项目摘要 帕金森病（PD）标准药物治疗的一个常见副作用是左旋多巴， 给药后的不自主运动称为左旋多巴诱导的运动障碍（LID）。消除 LID仍然是PD治疗中显著未满足的需求。目前没有FDA批准的药物治疗 然而，高达90%的PD患者会出现这种副作用。L-型钙通道CaV1.3是一种 LID预防的目标。PD中纹状体多巴胺（DA）的丢失导致调节障碍， 纹状体CaV1.3通道的过度活性导致突触病理学，包括树突棘的丧失， 纹状体棘状投射神经元似乎参与LID。虽然最初的研究提供了 药理学CaV1.3通道拮抗剂剂量依赖性地降低LID，其作用是部分的， 短暂的，由于现有药物缺乏特异性，可能导致心血管副作用 CaV1.3通道。为了提供明确的目标验证，没有药理学限制，我们 开发了一种rAAV-CaV 1.3-shRNA，以提供连续的、高效的、靶选择性的mRNA水平沉默 纹状体CaV1.3通道。我们研究了这些失调的钙通道的遗传沉默是否 是否可以预防先前左旋多巴未治疗过的帕金森病大鼠中的LID诱导和/或是否可以逆转 这些异常行为在已经表达严重LID表型的帕金森病大鼠中。在我们的'盖子 我们发现在严重帕金森病大鼠中纹状体CaV1.3通道的基因水平沉默， - 在引入左旋多巴之前提供均匀和完全的保护，防止LID的诱导，和 抗运动障碍的益处随时间持续，即使使用高剂量的每日左旋多巴。在我们的'盖子 逆转研究中，我们观察到rAAV介导的CaV1.3沉默在帕金森病大鼠中已经 建立LID可以改善这些行为，一周的药物戒断“药物假期”似乎 是有益的和/或必要的。重要的是，这种方法不会干扰左旋多巴的运动益处， 显示出增强对低剂量左旋多巴的运动反应的趋势。基因传递导致纹状体 CaV1.3沉默提供了迄今为止报道的一些最深刻的抗运动障碍益处。如果这些发现 可以转化为具有类似量级的临床应用，这将提供急需的 这是治疗PD患者的突破，将允许最强大的抗帕金森病治疗 在整个疾病期间都没有减弱。在本申请中，我们提出了一种 在大鼠和非人类灵长类动物中进行的一系列转化研究，将使我们能够扩展这些最初的研究。 原则验证研究，并测试临床试验所需的安全性和有效性的特定假设。 LID纹状体CaV1.3通道的遗传沉默的发展。

Project Summary One often debilitating side-effect of standard pharmacotherapy for Parkinson's disease (PD), levodopa administration, are unwanted involuntary movements known as levodopa-induced dyskinesia (LID). Eliminating LID remains a significant unmet need in PD therapy. There are currently no FDA approved drug treatments for LID, yet up to 90% of individuals with PD develop this side-effect. The L-type calcium channel CaV1.3 is a target of interest for LID prevention. Loss of striatal dopamine (DA) in PD results in dysregulation and overactivity of striatal CaV1.3 channels leading to synaptic pathology, including the loss of dendritic spines on striatal spiny projection neurons that appears to be involved in LID. While initial studies delivering pharmacological CaV1.3 channel antagonists reduced LID dose-dependently, the effects were partial and transient, with potential liability for cardiovascular side-effects due to the lack of specificity of existing drugs for the CaV1.3 channel. To provide unequivocal target validation, free of pharmacological limitations, we developed a rAAV-CaV1.3-shRNA to provide continuous, high potency, target-selective, mRNA-level silencing of striatal CaV1.3 channels. We examined whether genetic silencing of these dysregulated calcium channels could prevent LID induction in previously levodopa naïve parkinsonian rats and/or whether it could reverse these abnormal behaviors in parkinsonian rats already expressing a severe LID phenotype. In our `LID prevention studies' we found that gene level silencing of striatal CaV1.3 channels in severely parkinsonian rats, prior to the introduction of levodopa provides uniform and complete protection against the induction of LID, and that the antidyskinetic benefit is sustained over time even with high doses of daily levodopa. In our `LID reversal studies' we observed that rAAV-mediated CaV1.3 silencing in parkinsonian rats with already established LID could ameliorate these behaviors, with a one-week drug withdrawal 'drug holiday' appearing to be beneficial and/or necessary. Importantly this approach did NOT interfere with motor benefit of levodopa and showed a tendency to enhance motoric response to low dose levodopa. Gene delivery resulting in striatal CaV1.3 silencing provides some of the most profound antidyskinetic benefit reported to date. If these findings can be translated into a clinical application with a similar magnitude, this would provide a much-needed breakthrough in treatment of individuals with PD and would allow the most powerful antiparkinsonian therapy ever identified to work unabated through the duration of the disease. In the current application we propose a series of translational studies in rats and nonhuman primates that will allow us to expand upon these initial proof-of-principle studies and test specific hypotheses of safety and efficacy that will be required for the clinical development of genetic silencing of striatal CaV1.3 channels for LID.