Antisense oligonucleotides for the treatment of spinocerebellar ataxia type 2

描述（由申请人提供）： 神经退行性疾病是一种日益加重的社会和经济负担，世卫组织估计，到2040年，它们将取代癌症成为第二大死亡原因。在神经退行性疾病研究中，已经发现了大量的通路，但是它们与相应的人类疾病的直接和主要相关性一直难以证明，并且通路的靶向仍然很困难。拟议的工作将确定脊髓小脑共济失调2型（SCA 2）的治疗方法，SCA 2是一种影响小脑浦肯野神经元（PN）和小脑，脑干和大脑中其他神经元的遗传性神经退行性疾病。SCA 2的原因是ATXN 2基因中的功能获得性CAG扩增，导致共济失调蛋白-2中的多聚谷氨酰胺（polyQ）扩增。我们的目的是鉴定降低ATXN 2表达的反义寡核苷酸（ASO）。我们的基本原理是基于在模式生物和人类中的观察，表明较高剂量的突变等位基因/蛋白质使疾病严重程度恶化，并且即使在小鼠出现症状后，啮齿动物中突变polyQ蛋白表达的下调也会逆转临床表现。此外，在小鼠中完全敲除ATXN 2不会导致神经变性或过早死亡。本研究的优点得到了多种ASO临床试验的积极结果以及正在进行的测试ASO治疗肌萎缩性侧索硬化症（ALS）和脊髓性肌萎缩症（SMA）的临床试验的支持。可行性是基于已建立的资源，包括体外鉴定的主要ASO和具有晚发型进行性运动表型的充分表征的人BAC转基因小鼠模型。提出了三个具体目的：1）从我们已经在初步阿索筛选中鉴定的15种先导ASO中鉴定4种最有效的用于降低ATXN 2表达的ASO，2）测试阿索先导物用于改善生物化学内表型，包括维持神经胶质健康的指示，以及3）测试两种最有效的ASO用于改善SCA 2小鼠BAC模型中的运动表型。拟议的工作将通过证明用反义寡核苷酸靶向显性作用突变polyQ基因的可行性，为治疗神经退行性疾病开辟新的领域。

DESCRIPTION (provided by applicant): Neurodegenerative diseases represent an ever-increasing societal and economic burden with WHO estimates indicating that they will replace cancer as the 2nd leading cause of death by 2040. In neurodegenerative disease research, a wealth of pathways has been uncovered, but their direct and primary relevance to the respective human disease has been difficult to prove and targeting of pathways has remained difficult. The proposed work will identify a treatment for spinocerebellar ataxia type 2 (SCA2), a hereditary neurodegenerative disease affecting cerebellar Purkinje neurons (PNs) and other neurons in the cerebellum, brainstem and cerebrum. The cause of SCA2 is a gain-of-function CAG expansion in the ATXN2 gene resulting in an expanded polyglutamine (polyQ) in ataxin-2. Our objective is identification of antisense oligonucleotides (ASOs) that lower ATXN2 expression. Our rationale is based on observations in model organisms and humans indicating that higher dosages of the mutant allele/protein worsen disease severity and that down-regulation of mutant polyQ protein expression in rodents reverses clinical manifestations even after mice have become symptomatic. Additionally, complete knock-out of ATXN2 in mice does not cause neurodegeneration or premature death. Merit for this study is supported by positive results in clinical trials for multiple ASOs, and ongoing clinical trials to test ASOs for the treatment of amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). The feasibility is based on established resources including lead ASOs identified in vitro and a well-characterized human-BAC transgenic mouse model with late onset progressive motor phenotypes. Three specific aims are proposed: 1) Identification of the 4 most effective ASOs for lowering ATXN2 expression, from 15 lead ASOs that we have already identified in a preliminary ASO screen, 2) testing the ASO leads for amelioration of a biochemical endophenotype that includes indication of maintained glial health, and 3) testing the two most effective ASOs for ameliorating a motor phenotype in an SCA2 mouse BAC model. The proposed work will break new ground for treatment of neurodegenerative diseases by demonstrating feasibility of targeting dominant-acting mutated polyQ genes with antisense oligonucleotides.