Mechanisms of motor superperformance

运动超性能的机制

• 批准号: 10701427
• 负责人: Juan M. Pascual
• 金额: $ 53.97万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-21 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10701427
• 关键词: Adenoviruses; Animals; Behavioral; Binding; Biological Assay; Brain; Cells; Cerebellum; Chemicals; Clinical; Clustered Regularly Interspaced Short Palindromic Repeats; DNA; DNA Folding; DNA Repair; Data; Dependence; Dependovirus; Disease; Embryo; Ethylnitrosourea; Fibroblasts; Future; G-Quartets; GDF8 gene; Gait; Gene Expression; Genes; Genetic; Genetic Transcription; Genomics; Goals; Health; Hippocampus (Brain); Human; Impairment; Injections; Investigation; Laboratory mice; Locomotion; Mediating; Mediation; Mediator of activation protein; Messenger RNA; Methods; Mission; Motor; Movement; Mus; Muscular Dystrophies; Mutant Strains Mice; Mutate; Mutation; Neocortex; Nervous system structure; Neurologic; Organism; Outcome; Output; Performance; Persons; Pharmaceutical Preparations; Pharmacology; Phenotype; Population; Predisposition; Prosencephalon; Purkinje Cells; Radiation; Radiation Induced DNA Damage; Regulation; Resistance; Spinal Cord; Spinal Muscular Atrophy; Stroke; Synapses; Synaptic Transmission; System; Testing; Therapeutic; Transcript; Transcriptional Regulation; United States National Institutes of Health; Up-Regulation; Video Recording; Work; antagonist; base; behavior test; cancer type; disability; drug development; experience; functional gain; gene product; loss of function; loss of function mutation; malignant breast neoplasm; man; motor disorder; motor impairment; motor learning; motor recovery; mutant; nervous system disorder; neurophysiology; novel; overexpression; protein expression; screening; stem; stroke recovery; synaptic function; transcriptome; transcriptomics; treadmill

MECHANISMS OF MOTOR SUPERPERFORMANCE: ABSTRACT Clinical experience and world population-level data indicate that most neurological disability stems from motor dysfunction. Yet, spontaneous superperformer mutations occur in a variety of species including man, illustrating that the intrinsic motor capacity of the organism can be augmented. We set out to identify similar mutations by rotarod screening of 33,806 laboratory mice harboring chemically induced random mutations with the goal of mechanistically explaining and, eventually, pharmacologically enabling the phenomenon of motor superperformance. In this context, we have discovered that a mutation in an unsuspected gene, Rif1 (Replication Timing Regulatory Factor 1), confers supernormal motor ability. Using clustered regularly interspaced short palindromic repeats (CRISPR) Rif1-mutant mice, we have determined that: 1) mutant superperformance is a selective phenotype, with distinct changes in motor features quantifiable by our novel analysis method, but no other effects upon rigorous behavioral testing, and 2) the mutation also leads to accelerated motor recovery from stroke. The superperformance mechanism, however, is unknown: although Rif1 participates in DNA repair and in transcriptional regulation via G4 folded DNA structural stabilization, little is known about its function in the nervous system. There is precedent that DNA repair may be associated to synaptic transmission strength, while DNA G4 regulation could enhance the transcription of genes active in the motor system. We have refined this hypothetical framework by identifying several consequences of the Rif1 mutation: a) Increased cerebellar Purkinje cell firing regularity and local field potential changes in the non- moving mouse, which can influence movement precision, with change of these neurophysiological parameters upon locomotion on a treadmill; b) Increased resistance to DNA-damaging radiation; c) Increased resistance to G4 stabilization; d) Overexpression of a fraction of the cerebellar (but not forebrain or spinal cord) synaptic transcriptome including potential Rif1 mutation mediators such as Kcnma1, Kif5c and Nab2; e) These transcripts may be relevant to the phenotype because we show that loss of function mutations in them degrade motor performance, whereas f) Cerebellar injection of adenovirus-containing Nab2 induces superperformance. This proposal unifies this body of work by postulating that the Rif1 mutation modifies DNA repair and/or G4 DNA folding resulting in upregulation of synaptic transcripts, with either one or both mechanisms augmenting the precision of cerebellar synapse activity relevant to movement control. To this effect, we will conduct neurophysiological studies, determine the transcriptome in single cells, alter Kcnma1, Kif5c and Nab2 expression, and investigate DNA repair and DNA G4 regulation to test which of these mechanisms enable the superperformance phenotype. Our goal is to initiate and steer the mechanistic investigation (by us or any others) of Rif1 in the brain for ultimate therapeutic gain if appropriate.

运动超性能的机制：摘要 临床经验和世界人口水平的数据表明，大多数神经功能障碍源于运动 功能障碍。然而，自发的超级突变发生在包括人类在内的多种物种中， 说明有机体的内在运动能力可以增强。我们开始寻找类似的 通过转棒筛选 33,806 只携带化学诱导随机突变的实验室小鼠，进行突变 目标是从机械上解释并最终从药理学上实现运动现象 超强表现。在这种情况下，我们发现了一个未被怀疑的基因 Rif1 的突变 （复制计时调节因子1），赋予超常的运动能力。定期使用集群 间隔短回文重复序列 (CRISPR) Rif1 突变小鼠，我们确定：1) 突变体 超级表现是一种选择性表型，运动特征的明显变化可以通过我们的小说量化 分析方法，但对严格的行为测试没有其他影响，并且2）突变也会导致 加速中风后的运动恢复。然而，超性能机制尚不清楚：尽管 Rif1 通过 G4 折叠 DNA 结构稳定参与 DNA 修复和转录调控，很少 已知其在神经系统中的功能。有先例表明 DNA 修复可能与 突触传递强度，而 DNA G4 调节可以增强突触中活跃基因的转录 电机系统。我们通过确定 Rif1 的几个后果完善了这个假设框架 突变：a）增加小脑浦肯野细胞放电规律和非非局部场电位变化 移动鼠标，随着这些神经生理参数的变化，会影响运动精度 在跑步机上运动时； b) 增强对 DNA 损伤性辐射的抵抗力； c) 增加抵抗力 G4稳定； d) 小脑（但不是前脑或脊髓）突触部分的过度表达 转录组，包括潜在的 Rif1 突变介质，例如 Kcnma1、Kif5c 和 Nab2； e) 这些 转录本可能与表型相关，因为我们发现它们的功能缺失突变会降解 运动表现，而 f) 小脑注射含有腺病毒的 Nab2 可诱导超强表现。 该提案通过假设 Rif1 突变修改 DNA 修复和/或 G4 来统一这一工作主体 DNA 折叠导致突触转录本上调，其中一种或两种机制都会增强 与运动控制相关的小脑突触活动的精度。为此，我们将进行 神经生理学研究，确定单细胞中的转录组，改变 Kcnma1、Kif5c 和 Nab2 表达，并研究 DNA 修复和 DNA G4 调节，以测试这些机制中的哪一个能够实现 超性能表型。我们的目标是发起并指导机械调查（由我们或任何机构进行） 如果合适的话，大脑中的 Rif1 可以获得最终的治疗效果。

项目成果

Genetic influences on motor learning and superperformance mutants revealed by random mutational survey of mouse locomotion.

通过对小鼠运动的随机突变调查揭示了遗传对运动学习和超性能突变体的影响。

• DOI: 10.1101/2023.06.28.546756
• 发表时间: 2023
• 期刊: bioRxiv : the preprint server for biology
• 作者: Jakkamsetti,Vikram;Ma,Qian;Angulo,Gustavo;Scudder,William;Beutler,Bruce;Pascual,JuanM
• 通讯作者: Pascual,JuanM