Improved HSV Vectors: Gene Transfer into Nervous System

描述（由申请人提供）：基因转移方法已经产生了 为人类神经系统疾病的基因治疗提供了机会， 帕金森病（PD）。由于PD代表一组临床相似的 每种综合征由不同的机制触发，我们假设存在 共同的下游病理生理通路。我们的目标是开发治疗 用于指向路径中的共享公共节点的PD。拟订这样 神经保护性基因治疗取决于安全、 有效的基因转移载体，其可以表达治疗性基因， 在特定的神经元群体中的时间延长。当前可用的 用于直接基因治疗的载体，仅基于质粒的单纯疱疹病毒（HSV） “扩增子”载体已被证明既容纳大的（9 kb） 酪氨酸羟化酶（TH）启动子片段，并提供高度选择性 黑质多巴胺（DA）神经元的基因表达。然而，HSV 扩增子载体表现出转基因沉默，这是一次性扩增的障碍。 给药治疗慢性疾病，如PD。我们的数据表明， 沉默由异染色质形成引起。其中一个目标是 项目是通过改变载体的倾向来破坏转基因沉默， 形成异染色质。在具体目标1中，我们研究了多种不同的 刺激常染色质形成的方法，即染色质状态假设为 支持长期基因表达。与发展有关的第二个问题 PD基因治疗的关键是将不同的治疗基因导向每个隔室 黑质纹状体通路的多巴胺神经元和目标纹状体。在 具体目标2：我们将开发单独的载体， 不同的基因产物表达到每个解剖隔室。第三 成功PD基因治疗的问题是在适当的动物模型中进行评价 疾病。具体目标3将采用两种动物模型： 发展进行性黑质纹状体功能障碍的α-突触核蛋白小鼠， 黑质TH和运动功能减退活动;和我们的修改慢性MPTP 模型产生纹状体去神经支配，多巴胺能细胞损失和 神经寄生虫综合征拟议的研究将产生优化的HSV 矢量，提供了详细的了解他们的特点， 评估它们在不同机制的PD模型中的有效性。

DESCRIPTION (provided by applicant): Gene transfer methods have created the opportunity for developing gene therapy for human neurological diseases such as Parkinson's Disease (PD). Since PD represents a group of clinically similar syndromes each triggered by a different mechanism we hypothesize the existence of a shared downstream pathophysiologic pathway. Our goal is to develop therapy for PD directed at a shared common node in the pathway. The elaboration of such neuroprotective gene therapy is contingent on the development of safe and efficacious gene transfer vectors that can express a therapeutic gene for a prolonged period in specific neuronal populations. Of the currently available vehicles for direct gene therapy only plasmid based herpes simplex virus (HSV) "amplicon" vectors have been demonstrated to both accommodate a large (9 kb) tyrosine hydroxylase (TH) promoter fragment and to provide highly selective gene expression in dopamine (DA) neurons in the substantia nigra. However, HSV amplicon vectors exhibit transgene silencing that is an impediment to one-time dosing for a chronic disease such as PD. Our data indicate that transgene silencing results from heterochromatin formation. One of the goals of this project is to subvert transgene silencing by altering the propensity of vector to form heterochromatin. In Specific Aim 1 we examine multiple different approaches to stimulate euchromatin formation, that chromatin state posited to support long term gene expression. A second issue pertinent to the development of PD gene therapy is to direct different therapeutic genes to each compartment of the diseased nigrostriatal pathway: dopamine neurons and target striatum. In Specific Aim 2 we will develop separate vectors which will afford direct expression of different gene products to each anatomical compartment. A third issue for successful PD gene therapy is evaluation in appropriate animal models of the disease. Specific Aim 3 will employ two animal models: Our novel a-synuclein mice which develop progressive nigrostriatal dysfunction, reduction of substantia nigra TH and hypokinetic activity; and our modified chronic MPTP model which produces striatal denervation, dopaminergic cell loss and a neurobehavorial syndrome. The proposed studies will yield optimized HSV vectors, provide a detailed understanding of their characteristics, and evaluate their effectiveness in mechanistically different models of PD.