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

项目摘要 帕金森病标准药物治疗的一种经常使人虚弱的副作用--左旋多巴 给药，是不受欢迎的非自愿运动，称为左旋多巴诱导的运动障碍(LID)。消除 LID仍然是PD治疗中一个重要的未得到满足的需求。目前还没有FDA批准的药物治疗 LID，然而高达90%的帕金森病患者会出现这种副作用。L型钙通道CaV1.3是一种 预防盖子的目标。帕金森病患者纹状体多巴胺(DA)的丢失导致调节失调和 纹状体CaV1.3通道过度活动导致突触病理，包括树突棘的丢失 纹状体棘投射神经元似乎与LID有关。虽然初步研究提供了 药理CaV1.3通道拮抗剂对LID的抑制作用呈剂量依赖关系，其作用具有部分和 暂时性的，由于现有药物缺乏特异性而可能导致心血管副作用 CaV1.3频道。为了提供明确的靶点验证，不受药理学限制，我们 开发了一种rAAV-CaV1.3-shRNA，提供持续、高效、靶向选择性、mRNA水平的沉默 纹状体CaV1.3通道。我们检查了这些调节失调的钙通道是否发生了遗传沉默 可以阻止先前左旋多巴幼稚帕金森病大鼠的LID诱导和/或是否可以逆转 帕金森病大鼠的这些异常行为已经表现出严重的LID表型。在我们的`LID 预防研究我们发现，严重帕金森病大鼠纹状体CaV1.3通道的基因水平沉默， 在引入左旋多巴之前，提供了统一和完全的保护，防止盖子的诱导，以及 即使每天服用高剂量的左旋多巴，抗运动障碍的益处也会随着时间的推移而持续。在我们的`LID 逆转研究：我们观察到rAAV介导的CaV1.3沉默帕金森病大鼠 现有的LID可以改善这些行为，为期一周的戒毒日似乎可以改善这些行为 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 对低剂量左旋多巴有增强运动反应的趋势。基因传递导致纹状体 CaV1.3沉默提供了一些迄今报道的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 帕金森病患者治疗方面的突破，将使最有效的抗帕金森病疗法成为可能 曾被确定在疾病持续期间有增无减地工作。在本申请中，我们提出了一种 在老鼠和非人灵长类动物中进行的一系列翻译研究，将使我们能够扩展这些最初的 临床所需的原则验证研究和测试安全性和有效性的特定假设 LID纹状体CaV1.3通道遗传沉默的研究进展

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.