Investigation of ApiCCT1 for Huntingtons disease therapeutics

描述（由申请人提供）：亨廷顿氏病（HD）是一种遗传性神经退行性疾病，可导致普遍的神经元功能障碍和死亡，尤其是纹状体的中棘神经元。目前还没有针对HD的疾病改善疗法。HD的病理特征是突变亨廷顿蛋白（mHTT）的积累和聚集，最终导致神经元和神经突内的核内和胞质包涵体。虽然聚集在HD进展中的作用尚不清楚，但mHTT聚集是疾病的一个标志。辅助折叠新合成蛋白和重新折叠错误折叠蛋白的伴侣蛋白是针对体内mHTT聚集的有趣的候选治疗方法。CCT1是伴侣复合物的一个亚基，在蛋白质从头合成过程中结合和折叠蛋白质，可以调节mHTT片段介导的聚集和毒性。只有CCT1的顶端结构域ApiCCT1可以调节体外聚集，并结合HTT的前17个AAs。我们发现外源性递送ApiCCT1可以减少mHTT的聚集，降低mHTT介导的HD细胞模型毒性，使ApiCCT1成为一种有前景的HD治疗药物。在本提案中，我们提供了一种策略来进一步研究ApiCCT1对mHTT聚集的细胞效应，评估ApiCCT1递送的体内潜力，并研究干细胞连续递送sApiCCT1作为HD的一种新的疾病改善治疗选择。具体目的1：研究ApiCCT1调节mHTT聚集物种的机制。mHTT聚集ApiCCT1的降低可能通过多种途径介导。本研究的目的是研究ApiCCT1的作用机制，为ApiCCT1作为一种潜在的治疗方法提供信息。特异性目标2：研究ApiCCT1作为治疗药物的潜力，并测试其在体内聚集的作用。这些实验将测试ApiCCT1对体内聚集的影响，支持机制研究，并检查ApiCCT1连续递送作为治疗方法的潜力。特异性目的3：确定干细胞介导的ApiCCT1传递对HD表型的影响。基于细胞的方法递送治疗分子并提供多种治疗活动本身可能提供更有效的方法。因此，我们建议研究一种基于干细胞的治疗策略，以提供ApiCCT1连续递送到纹状体。这些实验将表明联合神经营养支持与ApiCCT1递送是否足以改善生化和行为结果测量。这种联合疗法有可能极大地影响HD的临床治疗。我们假设ApiCCT1的传递将通过阻止聚集和促进mHTT降解来调节HD表型，并且sApiCCT1的干细胞传递将提供额外的神经保护，从而提供一种新的疾病修饰HD治疗的潜力。

DESCRIPTION (provided by applicant): Huntington's disease (HD) is a hereditary neurodegenerative disease that results in pervasive neuronal dysfunction and death, particularly in the medium spiny neurons of the striatum. There are currently no disease-modifying therapies for HD. A pathological hallmark of HD is accumulation and aggregation of mutant huntingtin protein (mHTT), ultimately resulting in intranuclear and cytoplasmic inclusions within neurons and neurite processes. While the role of aggregation in HD progression is not clear, mHTT aggregation is a marker of disease. Chaperones that assist in the folding of newly synthesized proteins and refold misfolded proteins are intriguing candidate therapeutics to target mHTT aggregation in vivo. CCT1, a subunit of a chaperone complex that binds and folds proteins during de novo protein synthesis, can modulate aggregation and toxicity mediated by a fragment of mHTT. Just the apical domain of CCT1, ApiCCT1, can modulate aggregation in vitro and binds the first 17 AAs of HTT. We find that exogenous delivery of ApiCCT1 decreases aggregation of mHTT and reduces mHTT-mediated toxicity in cell models of HD, making ApiCCT1 a promising therapeutic for HD. In this proposal we provide a strategy to further investigate the cellular effects of ApiCCT1 on mHTT aggregation, evaluate the in vivo potential of ApiCCT1 delivery, and examine continuous delivery of sApiCCT1 by stem cells as a novel disease-modifying therapy option for HD. Specific Aim 1: Investigate mechanism by which ApiCCT1 modulates mHTT aggregation species. The reduction of mHTT aggregation ApiCCT1 may be mediated by multiple pathways. The goal of this aim is to examine mechanisms of ApiCCT1 action to inform the use of ApiCCT1 as a potential therapy. Specific Aim 2: Examine potential of ApiCCT1 as a therapeutic agent and test effects on aggregation in vivo. These experiments will test ApiCCT1 effects on aggregation in vivo, support mechanistic studies, and examine the potential of continuous ApiCCT1 delivery as a therapeutic approach. Specific Aim 3: Determine efficacy of stem cell mediated delivery of ApiCCT1 on HD phenotypes. Cell-based approaches to deliver therapeutic molecules and also provide multiple therapeutic activities themselves may provide a more effective method. Therefore, we propose to investigate a stem cell-based therapeutic strategy to provide continuous delivery of ApiCCT1 to the striatum. These experiments will indicate if combining neurotrophic support with ApiCCT1 delivery is sufficient to improve biochemical and behavioral outcome measures. A combination therapy of this kind has the potential to greatly influence clinical treatment of HD. We hypothesize that delivery of ApiCCT1 will modulate HD phenotypes by preventing aggregation and facilitating mHTT degradation and that stem cell delivery of sApiCCT1 will provide additional neuroprotection, thus offering the potential for a novel disease-modifying HD therapy.