Novel genetic modifiers of C9orf72 and Tau toxicity

C9orf72中六核苷酸(GGGGCC)重复扩增是导致 额颞性痴呆(FTD)和肌萎缩侧索硬化症(ALS)。在这项提案中，我们试图确定 利用遗传多样性的C9-FTD/ALS小鼠模型进行新的治疗靶点。在这项研究设计中，我们 将使用腺相关病毒(AAV)驱动突变的C9重复表达(AAV-149R)在一组 协作杂交(CC)重组近交系小鼠以及从 CC菌株的随机重复异交。总体而言，CC和DO小鼠种群提供了很高的 图谱分辨率和广泛的等位基因多样性，携带4500万个SNP和结构变异。这提供了一种 在体内发现调节C9-重复毒性的新基因的独特机会。这些修饰符将是 与将注射AAV-TauP301L以确定修饰剂的CC/DO小鼠的平行研究相比 牛磺酸毒性。在目标1中，我们将使用CC小鼠来鉴定对C9或tau毒性敏感或耐药的菌株 而在目标2中，我们将使用DO小鼠来精细地映射这些潜在的修饰物。在目标3中，我们将表演单人- AAV-149R和AAV-TauP301L小鼠症状前阶段以及AAV-TauP301L小鼠的细胞RNA序列研究 以确定大脑对这些病理反应的进化 单个细胞水平。同样在目标3中，我们将对死后人类组织进行单核RNAseq 健康对照组，额叶皮质c9-ALS、c9-FTD和FTLD-TauP301L。来自这些数据集的最高命中率将是 用于确定来自目标1和目标2的候选基因/基因座的优先顺序，并后续进行验证研究 组织学和生化水平的死后组织。在这项全面研究的结论中，我们 希望已经确定了这两种疾病的众多修饰因素，可以进行更深入的跟踪 由我们的实验室或更广泛的科学界进行的功能研究。很可能这些基因中的一些 修饰剂也可能影响其他神经退行性疾病，如阿尔茨海默病、帕金森氏症 疾病等，并可通过在这些疾病模型中进行有针对性的测试进行跟踪。

Hexanucleotide (GGGGCC) repeat expansions in C9orf72 are the leading genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). In this proposal, we seek to identify new therapeutic targets by using a genetically diverse mouse model of C9-FTD/ALS. In this study design, we will be using adeno-associated virus (AAV) to drive mutant C9-repeat expression (AAV-149R) in a panel of Collaborative Cross (CC) recombinant inbred mice, as well as Diversity Outbred (DO) mice produced from random repeated outcrossing of CC strains. Collectively, the CC and DO mouse populations offer high mapping resolution and broad allelic diversity, carrying 45 million SNPs and structural variants. This provides a unique opportunity to discover new genes that regulate C9-repeat toxicity in vivo. These modifiers will be compared to a parallel study of CC/DO mice that will be injected with AAV-TauP301L to determine modifiers of tau toxicity. In Aim 1 we will use CC mice to identify strains that are sensitive or resistant to C9 or tau toxicity while in Aim 2 we will use the DO mice to finely map these potential modifiers. In Aim 3 we will perform single- cell RNAseq studies from AAV-149R and AAV-TauP301L mice at stages of pre-symptomatic, as well as moderate and severe disease to determine the evolution of the brain response to these pathologies at the individual cell level. Also in Aim 3, we will perform single-nucleus RNAseq on postmortem human tissue from healthy controls, c9-ALS, c9-FTD, and FTLD-TauP301L from frontal cortex. Top hits from these datasets will be used to prioritize candidate genes/loci from Aims 1 and 2, and followed up with validation studies on postmortem tissue at the histological and biochemical level. At the conclusion of this comprehensive study, we hope to have identified numerous modifiers of both diseases that can be followed up for more in depth functional studies by our laboratories or the broader scientific community. It is likely that some of these genetic modifiers could also impact other neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, etc. and could be followed up by targeted testing in those disease models.