A humanized mouse model for UBQLN2-associated ALS-dementia

UBQLN2 相关 ALS 痴呆的人源化小鼠模型

• 批准号: 10754023
• 负责人: Randal Scot Tibbetts
• 金额: $ 42.76万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10754023
• 关键词: Alleles; Behavior; Behavior assessment; Behavioral; Birth; Cell model; Cells; Client; Clinical; Cognitive; Defect; Dementia; Disease; Disease Pathway; Drosophila genus; Enterobacteria phage P1 Cre recombinase; Evaluation; Exhibits; Frontotemporal Dementia; Gene Dosage; Gene Targeting; Genes; Genetic; Glean; Goals; Histopathology; Homeostasis; Human; Knock-in; Learning; Legal patent; Link; Mammals; Masks; Memory; Modeling; Molecular Chaperones; Motor; Motor Neurons; Mouse Strains; Mus; Mutation; Nerve Degeneration; Nervous Mouse; Nervous System; Neurodegenerative Disorders; Neurologic; Other Genetics; Pathway interactions; Phenotype; Point Mutation; Primary Lateral Sclerosis; Proline; Protein Overexpression; Proteins; Rodent; Rodent Model; Sclerosis; Site; Solubility; Spastic Paraplegia; Study models; Switch Genes; Testing; Tissues; Toxic effect; Transgenic Organisms; Ubiquitin; Work; combinatorial; constitutive expression; embryonic stem cell; expectation; fly; frontotemporal lobar dementia amyotrophic lateral sclerosis; human disease; human model; humanized mouse; induced pluripotent stem cell; motor behavior; motor neuron degeneration; mouse model; multicatalytic endopeptidase complex; mutant; nestin protein; neurodegenerative phenotype; overexpression; protein aggregation; targeted treatment; tool; ubiquilin

Abstract The objective of this R21 proposal is to develop a humanized mouse model for UBQLN2-associated amyotrophic sclerosis (ALS) and frontotemporal dementia (FTD), devastating neurodegenerative disorders that lie on either end of a clinical disease spectrum. Among more than 20 different genes implicated in ALS/FTD, X-linked mutations in the ubiquitin (Ub) chaperone UBQLN2 cause diverse neurologic phenotypes, ranging from pure ALS with or without FTD, to primary lateral sclerosis and spastic paraplegia. ALS/FTD-associated mutations in UBQLN2 disrupt its folding and promote its aggregation; however, the mechanisms whereby UBQLN2 mutations instigate neurodegeneration in ALS/FTD are unclear. UBQLN2 mutant transgenic rodents recapitulated UBQLN2 histopathology but manifested highly discrepant neurological phenotypes ranging from patent motor neuron degeneration to no observable phenotype. A caveat to these studies—and transgenic rodent models in general—is that overexpression of wild-type UBQLN2 also elicits toxicity, likely through disruption of Ub homeostasis. On the other hand, while there is a strong need for models in which culprit ALS mutations are expressed at endogenous levels, mice harboring ALS-associated UBQLN2 knockin mutations exhibit weak phenotypes, precluding mechanistic studies. This has been a general problem for mouse models of human neurodegenerative diseases. In an attempt to augment UBQLN2 toxicity at endogenous expression levels, our group developed a combinatorial UBQLN2 mutant (UBQLN24XALS) harboring four different clinical mutations that reduce its solubility in a semi-additive manner. UBQLN24XALS caused enhanced toxicity relative to wild-type UBQLN2 or UBQLN2 clinical mutants when overexpressed in Drosophila or when expressed from a UBQLN2 knockin allele in iPS-derived motor neurons (iMNs). Genetic suppressors of UBQLN24XALS toxicity in Drosophila also suppressed its toxicity in iMNs suggesting that UBQLN24XALS toxicity mechanism is at least partially conserved in flies and mammals. Here, we propose to generate a conditional, humanized UBQLN24XALS mouse model to allow spatially and temporally controlled UBQLN24XALS in the mouse nervous system. After a full evaluation of neurodegenerative phenotypes, UBQLN24XALS mice will be used as a tool to decipher ALS disease pathways using ‘omics approaches and information gleaned from orthologous studies in Drosophila and cellular models of ALS-UBQLN2. Information learned should also inform ALS/FTD arising sporadically and from other genetic causes. The objectives of the proposal are to: 1) Generate conditional, humanized UBQLN2WT to UBQLN24XALS gene switch mice; 2) Histopathologic and behavioral assessment of Nestin (Nes)-Cre, UBQLN24XALS mice.

抽象的 该R21提案的目的是开发与UBQLN2相关的人源化小鼠模型 肌萎缩性硬化症（ALS）和额颞痴呆（FTD），毁灭性神经退行性疾病 这位于临床疾病谱的两端。在实施的20多种不同基因中 泛素（UB）伴侣UBQLN2中的ALS/FTD，X连锁突变引起了潜水员神经系统 表型，范围从具有或没有FTD的纯AL到原发性硬化症和痉挛性截瘫。 UBQLN2中的ALS/FTD相关突变破坏了其折叠并促进其聚集；但是， UBQLN2突变​​激发ALS/FTD中神经变性的机制尚不清楚。 UBQLN2 突变的转基因啮齿动物概括了UBQLN2组织病理学，但表现出高度差异 从专利运动神经元变性到无观察表型的神经表型。一个 这些研究的警告以及一般的转基因啮齿动物模型是野生型的过表达 UBQLN2也可能通过破坏UB稳态引起毒性。另一方面，当 非常需要在内源水平上表达罪魁祸首突变的模型，小鼠 携带与ALS相关的UBQLN2敲击素突变暴露于弱表型，排除机械 研究。对于人类神经退行性疾病的小鼠模型来说，这是一个普遍的问题。 为了在内源表达水平上增加UBQLN2毒性，我们的小组开发了 组合UBQLN2突变​​体（UBQLN24XALS）具有四种不同的临床突变 以半添加方式溶解性。 UBQLN24XALS相对于野生型UBQLN2引起毒性增强 当在果蝇中过表达或从ubqln2表达时，或UBQLN2临床突变体 IPS衍生的运动神经元（IMN）中的敲击等位基因。 UBQLN24XAX毒性的遗传补充剂 果蝇还抑制了其在IMN中的毒性，表明UBQLN24XAX毒性机制至少是 在苍蝇和哺乳动物中部分保守。在这里，我们建议生成有条件的人性化 UBQLN24XALS鼠标模型允许在小鼠神经中在空间和暂时控制的UBQLN24XALS模型 系统。在对神经退行性表型进行完整评估后，UBQLN24XAX小鼠将用作工具 使用“ OMICS”方法和从直系同源收集的信息破译ALS疾病途径 果蝇和ALS-UBQLN2细胞模型的研究。学习的信息也应信息 ALS/FTD偶尔出现并来自其他遗传原因。该提案的目标是：1） 生成条件人源化的UBQLN2WT到UBQLN24XAX基因开关小鼠； 2）组织病理学和 Nestin（NES）-CRE，UBQLN24XAX小鼠的行为评估。