Huntington's Disease Antisense Transcript

亨廷顿病反义转录本

• 批准号: 7897196
• 负责人: RUSSELL L MARGOLIS
• 金额: $ 20.5万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-15 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7897196
• 关键词: Address; Affect; Biological Models; Brain; Brain region; CAG repeat; Cell model; Cells; Chromosomes; Data; Development; Disease; Exons; FMR1; Fragile X Syndrome; Funding; Generations; Genes; Genome; Human; Huntington Disease; Lead; Length; Location; Maps; Mediating; Modeling; Myotonic Dystrophy; Neurodegenerative Disorders; Nomenclature; Pathogenesis; Patients; Pattern; Process; RNA Splicing; Regulation; Relative (related person); Role; Series; Small Interfering RNA; Staging; Structure; Testing; Therapeutic; Therapeutic Agents; Tissues; Toxic effect; Transcript; Translating; Type 1 Spinocerebellar Ataxia; United States; Variant; base; design; human DICER1 protein; human Huntingtin protein; insight; mind control; mouse genome; mouse model; mutant; novel strategies; novel therapeutics; overexpression; polyglutamine; promoter; public health relevance; research study; therapeutic target

DESCRIPTION (provided by applicant): Huntington's disease (HD) is a fatal neurodegenerative disorder, affecting about 30,000 people in the United State, and caused by an expansion of a CAG repeat (encoding polyglutamine) in the gene huntingtin located on chromosome 4p. While ample evidence supports a major role for polyglutamine toxicity in the pathogenesis of Huntington's disease (HD), the complete explanation for HD pathogenesis remains elusive. Recent evidence suggests that transcripts antisense to genes are present throughout the genome. In particular, antisense transcripts with potential roles in disease pathogenesis have been detected at the locus of a number of repeat expansion diseases, including fragile X, myotonic dystrophy type 1, spinocerebellar ataxia type 8, and Huntington's disease-like 2. Our preliminary data indicates that 1) an antisense transcript spanning the CAG/CTG repeat region at the HD locus (termed huntingtin antisense, abbreviated HTTAS) exists and is expressed in multiple brain regions; 2) HTTAS promoter activity is inversely proportional to the length of the CAG/CTG repeat, 3) HTTAS is decreased in HD brain compared to control brain, and 4) exogenous overexpression of HTTAS decreases huntingtin (HTT) levels, while knockdown of HTTAS increases HTT levels. We have also developed a series of constructs modeling the HD locus, which demonstrates the repeat-length dependent influence of HTTAS on HTT. Based on this initial data, we hypothesize that HTTAS influences HTT expression in a repeat length-dependent manner, with consequent impact on HD pathogenesis. We will test this hypothesis in Aim 1 by mapping the complete HTTAS gene in the human and mouse genome, confirming the repeat-length dependent actiivty of the promoter, and determining the pattern of HTTAS1 expression in normal and HD brain. In Aim 2, we will use cell models to determine the effect of HTTAS on HTT expression both in cis and in trans, and in the setting of normal and expanded repeats. These experiments will enable us to establish the existence and function of HTTAS, and provide us with sufficient preliminary data to compete for long term funding for this project. Ultimately, understanding the relationship between HTT and HTTAS will provide new insights into the mechanism of HD pathogenesis and may lead to the development of novel therapeutic strategies. PUBLIC HEALTH RELEVANCE: Antisense transcripts appear to regulate mutant transcripts in a number of diseases, including several repeat expansion diseases. We propose to test the hypothesis that an antisense transcript at the HD locus regulates huntingtin. If confirmed, antisense regulation would provide a new approach to understanding the pathogenesis of HD, and new approaches for developing therapeutic agents for HD.

描述（由申请人提供）：亨廷顿病 (HD) 是一种致命的神经退行性疾病，影响美国约 30,000 人，由位于染色体 4p 上的亨廷顿基因中的 CAG 重复序列（编码聚谷氨酰胺）的扩展引起。虽然大量证据支持多聚谷氨酰胺毒性在亨廷顿病 (HD) 发病机制中发挥重要作用，但 HD 发病机制的完整解释仍然难以捉摸。最近的证据表明，基因反义转录本存在于整个基因组中。特别是，在许多重复扩增疾病的位点上检测到了在疾病发病机制中具有潜在作用的反义转录本，包括脆性X、强直性肌营养不良1型、脊髓小脑性共济失调8型和亨廷顿病样2型。我们的初步数据表明，1）跨越HD位点处的CAG/CTG重复区域的反义转录本（称为亨廷顿蛋白） 反义，缩写为HTTAS）存在并在多个大脑区域表达； 2) HTTAS 启动子活性与 CAG/CTG 重复序列的长度成反比，3) 与对照脑相比，HD 脑中 HTTAS 降低，4) HTTAS 的外源过度表达会降低亨廷顿蛋白 (HTT) 水平，而 HTTAS 的敲除会增加 HTT 水平。我们还开发了一系列 HD 基因座建模结构，证明了 HTTAS 对 HTT 的重复长度依赖性影响。基于这些初始数据，我们假设 HTTAS 以重复长度依赖性方式影响 HTT 表达，从而影响 HD 发病机制。我们将通过在人类和小鼠基因组中绘制完整的 HTTAS 基因图谱，确认启动子的重复长度依赖性活性，并确定正常和 HD 大脑中 HTTAS1 的表达模式，来测试目标 1 中的这一假设。在目标 2 中，我们将使用细胞模型来确定 HTTAS 对顺式和反式以及正常和扩展重复设置中 HTT 表达的影响。这些实验将使我们能够确定HTTAS的存在和功能，并为我们竞争该项目的长期资金提供足够的初步数据。最终，了解 HTT 和 HTTAS 之间的关系将为 HD 发病机制提供新的见解，并可能导致新治疗策略的开发。 公共健康相关性：反义转录本似乎可以调节许多疾病中的突变转录本，包括几种重复扩增疾病。我们建议检验 HD 基因座的反义转录本调节亨廷顿蛋白的假设。如果得到证实，反义调控将为理解 HD 发病机制提供新方法，并为开发 HD 治疗药物提供新方法。