Investigation of ApiCCT1 for Huntingtons disease therapeutics

描述（由申请人提供）：亨廷顿病（HD）是一种遗传性神经退行性疾病，其导致广泛的神经元功能障碍和死亡，特别是在纹状体的中型多棘神经元中。目前尚无针对HD的疾病缓解疗法。HD的病理标志是突变亨廷顿蛋白（mHTT）的积累和聚集，最终导致神经元和神经突过程中的核内和细胞质内含物。虽然聚集在HD进展中的作用尚不清楚，但mHTT聚集是疾病的标志物。协助新合成蛋白质折叠和重新折叠错误折叠蛋白质的伴侣是针对体内mHTT聚集的有趣候选疗法。CCT 1是分子伴侣复合物的一个亚基，在从头蛋白质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CCT 1的顶端结构域ApiCCT 1可以在体外调节聚集并结合HTT的前17个AA。我们发现ApiCCT 1的外源性递送减少了mHTT的聚集，并降低了HD细胞模型中mHTT介导的毒性，使ApiCCT 1成为一种有希望的HD治疗药物。在该提案中，我们提供了一种策略，以进一步研究ApiCCT 1对mHTT聚集的细胞效应，评估ApiCCT 1递送的体内潜力，并检查干细胞连续递送sApiCCT 1作为HD的新型疾病修饰治疗选择。具体目的1：研究ApiCCT 1调节mHTT聚集物质的机制。mHTT聚集ApiCCT 1的减少可能由多种途径介导。本研究旨在研究ApiCCT 1的作用机制，为ApiCCT 1作为潜在疗法的使用提供信息。具体目的2：检查ApiCCT 1作为治疗剂的潜力，并测试对体内聚集的影响。这些实验将测试ApiCCT 1对体内聚集的影响，支持机制研究，并检查连续ApiCCT 1递送作为治疗方法的潜力。具体目标3：确定干细胞介导的ApiCCT 1递送对HD表型的功效。基于细胞的递送治疗分子的方法本身也提供多种治疗活性，这可能是一种更有效的方法。因此，我们建议研究一种基于干细胞的治疗策略，以向纹状体提供ApiCCT 1的连续递送。这些实验将表明，将神经营养支持与ApiCCT 1递送相结合是否足以改善生化和行为结果指标。这种联合治疗有可能极大地影响HD的临床治疗。我们假设ApiCCT 1的递送将通过防止聚集和促进mHTT降解来调节HD表型，并且sApiCCT 1的干细胞递送将提供额外的神经保护，从而为新型疾病修饰HD疗法提供潜力。

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.