Validation of ubiquilin for Huntingtons disease

泛素对亨廷顿病的验证

• 批准号: 8637268
• 负责人: Mervyn J Monteiro
• 金额: $ 23.03万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8637268
• 关键词: Affect; Animals; Attenuated; Autophagocytosis; Behavioral; Behavioral Assay; Biochemical; Brain; Brain region; Caenorhabditis elegans; Cell Culture Techniques; Cells; Complement; Corpus striatum structure; Culture Media; Defect; Development; Disease; Disease model; Embryo; Evaluation; Exons; Fibroblasts; Health; Hippocampus (Brain); Human; Huntington Disease; In Vitro; Knock-in Mouse; Lead; Length; Longevity; Modeling; Mus; Neurologic; Neurons; Pathogenesis; Pathology; Pathway interactions; Penetrance; Phenotype; Physiological; Proteins; Research; Staging; Symptoms; Testing; Tetanus Helper Peptide; Time; Toxic effect; Transgenic Mice; Transgenic Organisms; Validation; base; effective therapy; human Huntingtin protein; human UBQLN1 protein; human disease; insight; method development; mouse model; multicatalytic endopeptidase complex; mutant; neuropathology; overexpression; polyglutamine; prevent; promoter; protein aggregation; public health relevance; research study; therapeutic target; tool; ubiquilin

DESCRIPTION (provided by applicant): Huntington's disease (HD) is one of the most devastating human diseases known, affecting approximately 120,000 people in the USA. Despite extensive research there is currently no effective treatment for the disease. Our previous studies conducted in fibroblast, neuronal and C. elegans models of HD have shown that overexpression of ubiquilin (ubqln) reduces toxicity of mutant huntingtin (htt) proteins containing expanded polyglutamine repeats. The results suggest that modulation of ubqln expression might be an attractive target for treating HD. However, before such consideration, a necessary and important perquisite is to validate whether overexpression of ubqln can reduce HD-like symptoms in mouse models of the disease. To conduct such tests we have now obtained transgenic mice that overexpress human ubqln-1 throughout the brain, including the striatum and hippocampus. The mice are completely normal based on lifespan and behavioral assays. In an initial test we crossed our ubqln-1 transgenic mice with the R6/2 model of HD and found ubqln-1 overexpression almost completely restores a progressive decline in ubqln levels seen in the brains of R6/2 animals during late stages of the disease. Interestingly, ubqln-1 overexpression reduced htt protein aggregation and increased survival of R6/2 mice by 20%. Despite these alterations we found no significant difference in behavioral defects in the mice, which might be attributed to high expression and penetrance of the toxic R6/2 mutant htt exon- 1 transgenic fragment. It is important that we repeat the test with better models of HD. Two such models are the YAC128 and CAG knock-in mice, both of which express mutant full-length htt proteins at more physiological levels. These HD models have more attenuated HD symptoms over an extended period and should be better suited for our test. Therefore, in Aim 1 we will cross transgenic mice that overexpress human ubiquilin-1 with the YAC128 transgenic mice to evaluate whether ubiquilin-1 overexpression delays and/or prevents the time-course of development of neuropathology and disease symptoms in this model of HD. Aim 2 is a repetition of Aim 1, but differs in that we will use the CAG200 knock-in mouse model of HD instead of the YAC128 mice. We will complement these animal studies with in vitro studies using cultured neurons isolated from the mice that should provide mechanistic into the mode of ubiquilin action in regulating htt toxicity. The results from this study will provide a critical tet of whether ubqln overexpression can delay or prevent HD symptoms. If validated the results could have high impact for HD as it would suggest efforts to find factors that modulate ubiquilin expression could be successfully used for treatment of HD. We describe the next logical steps of how this could be done.

描述（由申请人提供）：亨廷顿舞蹈症 (HD) 是已知最具破坏性的人类疾病之一，影响美国约 120,000 人。尽管进行了广泛的研究，但目前尚无针对该疾病的有效治疗方法。我们之前在 HD 的成纤维细胞、神经元和线虫模型中进行的研究表明，泛素 (ubqln) 的过度表达可降低含有扩展的多聚谷氨酰胺重复序列的突变亨廷顿 (htt) 蛋白的毒性。结果表明，调节 ubqln 表达可能是治疗 HD 的一个有吸引力的靶点。然而，在进行这种考虑之前，一个必要且重要的前提条件是验证 ubqln 的过度表达是否可以减少该疾病小鼠模型中的 HD 样症状。为了进行此类测试，我们现在获得了在整个大脑（包括纹状体和海马体）过度表达人类 ubqln-1 的转基因小鼠。根据寿命和行为分析，这些小鼠完全正常。在初步测试中，我们将 ubqln-1 转基因小鼠与 HD 的 R6/2 模型杂交，发现 ubqln-1 过度表达几乎完全恢复了 R6/2 动物在疾病晚期大脑中 ubqln 水平逐渐下降的情况。有趣的是，ubqln-1 过度表达减少了 htt 蛋白聚集，并使 R6/2 小鼠的存活率增加了 20%。尽管有这些改变，我们发现小鼠的行为缺陷没有显着差异，这可能归因于有毒 R6/2 突变体 htt 外显子 1 转基因片段的高表达和外显率。重要的是我们用更好的高清模型重复测试。两个这样的模型是 YAC128 和 CAG 敲入小鼠，这两种模型都在更生理水平上表达突变全长 htt 蛋白。这些 HD 模型在较长时间内具有更减弱的 HD 症状，应该更适合我们的测试。因此，在目标 1 中，我们将过度表达人泛素 1 的转基因小鼠与 YAC128 转基因小鼠杂交，以评估泛素 1 过度表达是否延迟和/或阻止该 HD 模型中神经病理学和疾病症状的发展时间过程。目标 2 是目标 1 的重复，但不同之处在于我们将使用 HD 的 CAG200 敲入小鼠模型而不是 YAC128 小鼠。我们将使用从小鼠中分离的培养神经元进行体外研究来补充这些动物研究，这些研究应提供泛素调节 htt 毒性作用模式的机制。这项研究的结果将为 ubqln 过度表达是否可以延迟或预防 HD 症状提供关键的四项测试。如果得到验证，该结果可能会对 HD 产生重大影响，因为它表明寻找调节泛素表达的因子的努力可以成功地用于 HD 的治疗。我们描述了如何实现这一点的接下来的逻辑步骤。