Antisense oligonucleotides to treat spinal and bulbar muscular atrophy

 描述(申请人提供)：脊柱球肌萎缩症(SBMA)是一种无法治疗的运动神经元和骨骼肌退行性疾病，由雄激素受体(AR)基因中的CAG/谷氨酰胺束扩张引起。多聚谷氨酰胺受体(PolyQ AR)经历荷尔蒙依赖的核转位和展开，这是毒性和男性进行性肌肉无力发展所必需的步骤。虽然引起SBMA突变的疾病早在20多年前就被发现，但SBMA发病机制仍然知之甚少。作为另一种关注被PolyQ AR干扰的下游通路的选择，我们建议测试一种新的治疗策略，使用反义寡核苷酸(ASO)来下调突变基因的表达。这项应用的目的是完成SBMA敲入小鼠模型的临床前研究，以确定外周注射ASO的安全性和有效性。我们的中心假设是，多聚Q受体在外周的毒性是疾病发病机制的一个重要因素，也是一个有吸引力的治疗靶点。这一假说不同于针对CNS内毒性效应的领域研究，是基于我们使用ASO的初步发现，ASO在小鼠皮下给药后抑制AR基因在外周的表达，但不抑制CNS。这些ASO是在与专门生产ASO的公司Isis PharmPharmticals持续的学术和产业合作中开发的。与Isis合作，我们发现外围基因抑制可以挽救我们实验室开发的SBMA敲入小鼠模型中骨骼肌质量、肌纤维大小和寿命的缺陷。这些数据表明外周多聚Q-AR在疾病中的重要作用，并提出了一种新的治疗途径。利用表型、组织学、遗传学和生化分析，我们将建立改善SBMA基因敲入小鼠疾病的最佳ASO传递途径、剂量和时间进程(目标1)，并确定外周ASO治疗的长期效果(目标2)。如果成功，这些研究将提供临床前小鼠模型的基本疗效数据，然后在该项目的下一阶段继续进行优化和启用IND的研究，作为在人类SBMA患者进行临床试验的前奏。

 DESCRIPTION (provided by applicant): Spinobulbar muscular atrophy (SBMA) is an untreatable degenerative disorder of motor neurons and skeletal muscle caused by a CAG/glutamine tract expansion in the androgen receptor (AR) gene. The polyglutamine AR (polyQ AR) undergoes hormone-dependent nuclear translocation and unfolding, steps that are essential to toxicity and to the development of progressive muscle weakness in men. Although the disease causing mutation was identified over two decades ago, mechanisms central to SBMA pathogenesis remain poorly understood. As an alternative to focusing on downstream pathways disrupted by the polyQ AR, here we propose to test a novel therapeutic strategy using antisense oligonucleotides (ASO) to knock-down expression of the mutant gene. The objective of this application is to complete preclinical studies in a knock-in mouse model of SBMA to establish the safety and efficacy of peripherally delivered ASO. Our central hypothesis is that toxicity of the polyQ AR in the periphery is an important contributor to disease pathogenesis and an attractive therapeutic target. This hypothesis, which is distinct from efforts in the field aime at targeting toxic effects within the CNS, is based on our preliminary findings using ASO that suppress AR gene expression in the periphery but not CNS following subcutaneous administration to mice. These ASO were developed in an on-going academic-industrial partnership with Isis Pharmaceuticals, a company that specializes in ASO production. Working with Isis, we found that peripheral gene suppression rescues deficits in skeletal muscle mass, muscle fiber size, and lifespan in a knock-in mouse model of SBMA developed by our laboratory. These data point to an important role of peripheral polyQ AR in disease and suggest a novel route to therapy. Using phenotypic, histological, genetic and biochemical analyses we will establish the optimal ASO delivery route, dose and time course to ameliorate disease in SBMA knock-in mice (Aim 1), and determine the long-term effects of peripheral ASO therapy (Aim 2). If successful, these studies will provide essential efficacy data in a preclinical mouse model, which will then proceed to lead optimization and IND-enabling studies in the next stage of this project, as a prelude to a clinical trial in human SBMA patients.