Investigation of ApiCCT1 for Huntingtons disease therapeutics

描述(申请人提供)：亨廷顿病(HD)是一种遗传性神经退行性疾病，导致广泛的神经元功能障碍和死亡，特别是在纹状体的中等刺状神经元。目前还没有针对HD的疾病修饰疗法。HD的一个病理特征是突变的亨廷顿蛋白(MHTT)的聚集和聚集，最终导致神经元和突起内的核内和细胞质内包涵体。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。辅助新合成的蛋白质折叠和重新折叠错误折叠的蛋白质的伴侣是吸引人的靶向体内mHTT聚集的候选治疗药物。CCT1是伴侣复合体的一个亚单位，在从头合成蛋白质的过程中与蛋白质结合并折叠，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在体外可以调节聚集，并与HTT的前17个氨基酸结合。我们发现，在HD细胞模型中，外源性ApiCCT1减少了mHTT的聚集，并减少了mHTT介导的毒性，使ApiCCT1成为一种有前景的HD治疗方法。在这项建议中，我们提供了一种策略，以进一步研究ApiCCT1对mHTT聚集的细胞效应，评估ApiCCT1传递的体内潜力，并检验干细胞持续传递sApiCCT1作为HD的一种新的疾病修改治疗选择。具体目标1：研究ApiCCT1调节mHTT聚集物种的机制。MHTT聚集性ApiCCT1的减少可能是由多条途径介导的。这个目的的目的是研究ApiCCT1的作用机制，以了解ApiCCT1作为一种潜在的治疗方法的使用情况。具体目标2：检测ApiCCT1作为治疗药物的潜力和体内聚集的效果。这些实验将测试ApiCCT1对体内聚集的影响，支持机制研究，并检验连续传递ApiCCT1作为一种治疗方法的潜力。具体目标3：确定干细胞介导的ApiCCT1对HD表型的疗效。以细胞为基础的方法传递治疗分子并提供多种治疗活动本身可能提供一种更有效的方法。因此，我们建议研究一种基于干细胞的治疗策略，以提供ApiCCT1持续输送到纹状体。这些实验将表明，将神经营养支持与ApiCCT1传递相结合是否足以改善生化和行为结果指标。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的传递将通过防止聚集和促进mHTT的降解来调节HD表型，而干细胞传递sApiCCT1将提供额外的神经保护，从而为一种新的疾病修改HD疗法提供潜在的可能性。

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.