Immunotherapies for RAN protein diseases

项目摘要 重复扩增突变导致50多种神经退行性疾病，包括亨廷顿病 (HD)和C9 orf 72肌萎缩侧索硬化症。尽管有大量的研究，但没有有效的治疗方法， 任何一种疾病重复扩增突变通常是双向转录的， 相关的非AUG（RAN）翻译（1）。这个过程导致扩增RNA被翻译成 毒性RAN蛋白跨越所有阅读框，而不需要AUG或AUG样起始密码子（2）。 因为正义和反义扩增RNA都可以在每个阅读框中翻译，所以多达六个毒性扩增RNA可以在每个阅读框中翻译。 蛋白质可以由单一突变产生。据报道，RAN蛋白在疾病中积累- 11种扩张性疾病（1，3，4）患者的受累组织，包括亨廷顿病（HD）（5）和 脊髓小脑性共济失调8型（6），由CAG·CTG扩展突变引起，C9 orf 72， 由GGGGCC·GGCCCC膨胀引起（7-9）。有强有力的证据表明RAN蛋白是有毒的， 导致越来越多的重复扩增疾病，可能是一个有吸引力的治疗靶点。 在C9-ALS BAC转基因小鼠中的强有力的临床前数据表明，被动免疫治疗减少了RAN 蛋白质，改善行为，延长寿命，改善神经病理学表型，包括运动 C9-BAC转基因小鼠中的神经元存活（10）。虽然有前途，被动免疫疗法伴随着许多 缺点包括产生这些抗体的费用以及患者必须经常接受 注射剂这项提议的中心假设是，针对RAN蛋白的疫苗接种将是有效的免疫治疗。 在C9 orf 72 ALS和HD小鼠中引发有益的免疫应答并减轻疾病的策略。我建议 通过确定基于RNA的脂质体疫苗是否可以引发有益的免疫应答来验证这一假设， 在C9-ALS和HD小鼠模型中降低RAN蛋白水平并改善疾病。

Project Summary Repeat expansion mutations cause more than 50 neurodegenerative diseases, including Huntington’s disease (HD) and C9orf72 amyotrophic lateral sclerosis. Despite intense research, there are no effective treatments for any of these disorders. Repeat expansion mutations are often bidirectionally transcribed and can undergo repeat associated non-AUG (RAN) translation (1). This process results in the expansion RNAs being translated into toxic RAN proteins across all reading frames without the requirement for AUG, or AUG-like initiation codons (2). Because both sense and antisense expansion RNAs can be translated in each reading frame, up to six toxic proteins can be produced from a single mutation. RAN proteins have been reported to accumulate in disease- affected tissues of patients for 11 expansion diseases (1, 3, 4), including Huntington’s disease (HD) (5) and spinocerebellar ataxia type 8 (6) which are caused by CAG•CTG expansion mutations and C9orf72 which is caused by a GGGGCC•GGCCCC expansion (7-9). There is strong evidence that RAN proteins are toxic and contribute to a growing number of repeat-expansion disorders and could be an attractive therapeutic target. Strong preclinical data in C9-ALS BAC transgenic mice show that passive immunotherapy reduced RAN proteins, improved behavior, increased longevity, and improved neuropathological phenotypes including motor neuronal survival in C9-BAC transgenic mice (10). While promising, passive immunotherapy comes with many disadvantages including the expense to produce these antibodies and that patients must receive frequent injections. The central hypothesis of this proposal is that vaccination against RAN proteins will be an effective strategy to elicit a beneficial immune response and mitigate disease in C9orf72 ALS and HD mice. I propose to test this hypothesis by determining if RNA-based liposome vaccines can elicit beneficial immune responses that reduce RAN protein levels and improve disease in mouse models of C9-ALS and HD.