Contribution of RAN proteins to HD, SCA3 other CAG.CTG expansion diseases

项目摘要 自从我们在2011年发现重复关联的非ATG(RAN)运行翻译以来，我们和 其他研究表明，Ran蛋白在九种不同的扩张性疾病中积累。这些 蛋白质，可以从正义和反义扩展转录本中表达， 积聚在与疾病相关的人体组织中，包括脊髓小脑型共济失调8型(SCA8) 和亨廷顿病(HD)。我们现在有证据表明PolySer和PolyLeu Ran蛋白质 积聚在一组脊髓-海洋脑性共济失调(SCA1、2、3、6和7)中，其中CAG·CTG 扩增突变位于PolyGln开放阅读框中。此外，我们还有 开发了AAV和小分子方法来抑制RAN翻译。我们将使用这些 测试我们的中心假说的工具和遗传方法运行蛋白质病理学是一个 编码CAG·CTG扩张性疾病的聚谷氨酰胺共有的特征和 抑制PKR途径将降低RAN蛋白水平，减轻疾病。 我们将在三个具体目标中阐述我们的中心假设：(1)测试假设 RAN蛋白参与聚谷氨酰胺编码引起的脊髓小脑性共济失调(SCAs) CAG·CTG重复扩增突变。(2)检验SCA和HD运行的假设 蛋白质是有毒的，抑制PKR将降低RAN蛋白水平并改善细胞 HD和SCA3IPSC来源细胞的表型(3)：检验Ran蛋白的假说 利用基因作用独立于PolyGln效应的小鼠的HD和SCA3表型 和药理学方法。这些具体目标加在一起将决定 RAN蛋白在HD、SCA3和CAG·CTG重复扩张性疾病中的作用 将PKR抑制作为一种潜在的治疗方法来治疗这一大类 毁灭性的重复扩张性疾病。

Project Summary Since we discovered repeat associated non-ATG (RAN) RAN translation in 2011, we and others have shown that RAN proteins accumulate in nine different expansion disorders. These proteins, which can be expressed from both sense and antisense expansion transcripts, accumulate in disease-relevant human tissues including spinocerebellar ataxia type 8 (SCA8) and Huntington disease (HD). We now have evidence that polySer and polyLeu RAN proteins accumulate in a group of spinocebellar ataxias (SCA1, 2, 3, 6 and 7) in which the CAG·CTG expansion mutations are located in polyGln open reading frames. Additionally, we have developed AAV and small molecule approaches to inhibit RAN translation. We will use these tools and genetic approaches to test our central hypotheses that RAN protein pathology is a common feature shared across polyglutamine encoding CAG·CTG expansion disorders and that inhibiting the PKR pathway will reduce RAN protein levels and mitigate disease. We will address our central hypothesis in three specific aims (1) To test the hypothesis that RAN proteins contribute to spinocerebellar ataxias (SCAs) caused by polyglutamine encoding CAG·CTG repeat expansion mutations. (2) To test the hypothesis that SCA and HD RAN proteins are toxic and PKR inhibition will decrease RAN protein levels and improve cellular phenotypes in HD and SCA3 iPSC derived cells (3) : To test the hypothesis that RAN proteins contribute to HD and SCA3 phenotypes in mice independent of polyGln effects using genetic and pharmacological approaches. Taken together these specific aims will determine the contribution of RAN proteins to HD,SCA3 and CAG·CTG repeat expansion disorders and characterize PKR inhibition as a potential therapeutic approach for this large class of devastating repeat expansion diseases.