Mechanisms Underlying Axonopathy in Hereditary Spastic Paraplegia

遗传性痉挛性截瘫轴突病的潜在机制

• 批准号: 10611493
• 负责人: Anjon Audhya
• 金额: $ 37.54万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2027-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10611493
• 关键词: Address; Adverse effects; Affect; Age; Amyotrophic Lateral Sclerosis; Animals; Ataxia; Atrophic; Axon; Binding; Biochemical; Biochemistry; Birth; Brain; CRISPR/Cas technology; Cell Culture Techniques; Cells; Central Nervous System; Cerebral cortex; Clinical; Clustered Regularly Interspaced Short Palindromic Repeats; Corticospinal Tracts; Data; Defect; Dementia; Development; Disease; Disease Progression; Distal; Drug Screening; Electromyography; Endosomes; Equilibrium; Escherichia coli; Etiology; Eukaryotic Cell; Exhibits; Filament; Foundations; Future; Gait; Gait abnormality; Genes; Genetic study; Glutamates; Glycine; Goals; Hereditary Spastic Paraplegia; Histopathology; Homeostasis; Human; Immunohistochemistry; Impairment; In Vitro; Inhibitory Synapse; Intermediate Filament Proteins; Intermediate Filaments; Intervention; Late-Onset Disorder; Length; Lewy Bodies; Limb structure; Link; Lower Extremity; Maintenance; Mediating; Membrane; Membrane Proteins; Microtubules; Modeling; Molecular; Motor; Movement; Muscle Weakness; Mutation; Nerve Degeneration; Nerve Fibers; Neurodegenerative Disorders; Neurofilament Proteins; Neuronal Dysfunction; Neurons; Neurotransmitters; Onset of illness; Organelles; Paralysed; Parkinson Disease; Pathologic; Patients; Phenotype; Physiological; Physiology; Play; Positioning Attribute; Process; Proteins; Proteomics; Rattus; Recombinant Proteins; Research; Resolution; Rodent; Rodent Model; Role; Scaffolding Protein; Signal Transduction; Solid; Somatotype; Spinal Cord; Sprague-Dawley Rats; Swelling; Synapses; Technology; Testing; Therapeutic; Time; Variant; Work; axon guidance; axonal degeneration; axonopathy; combat; confocal imaging; disease phenotype; drug development; early onset; electron tomography; fusion gene; genome editing; gephyrin; imaging approach; in vivo; induced pluripotent stem cell; innovation; kinematics; live cell imaging; motor control; motor deficit; nervous system disorder; neurofilament; neuronal excitability; novel therapeutics; overexpression; programs; receptor; reconstitution; spasticity; spastin; stem; stem cell model; therapeutic target; time interval; trafficking

Project Summary Axonal degeneration within the corticospinal tract leads to several neurological diseases, including hereditary spastic paraplegias (HSPs), which are a clinically and genetically heterogeneous group of gait disorders characterized by poor balance, spasticity, and progressive muscle weakness that can ultimately result in paralysis. Leveraging parallel animal (rat) and induced pluripotent stem cell (iPSC)-based models, our goal is to develop a better understanding of the pathomechanisms that underlie neurodegeneration resulting from mutations in genes that cause HSP, with a longer term goal of using these models as platforms to identify new therapeutics to combat disease. Using CRISPR-mediated genome editing, we have developed physiologically relevant models that recapitulate phenotypes exhibited by patients suffering from HSP. Specifically, CRISPR- modified rats expressing pathological variants of SPG4 (spastin) and SPG57 (TFG) demonstrate early onset hind limb spasticity and ataxia, which rapidly progresses to hind limb paralysis. Other rat models, including those harboring a truncation of SPG80 (UBAP1) identified previously in patients, exhibit later onset disease phenotypes, enabling us to examine disease progression in multiple, unique contexts. We now have an unprecedented opportunity to determine the mechanistic basis of the axonopathies observed. In particular, we plan to use high- resolution, live cell confocal imaging and electron tomography to test the hypothesis that changes in the trafficking of specific factors, including neurofilament proteins implicated previously in neurodegenerative disease, contribute to impaired neuronal function in HSP. We will also determine how neurofilament trafficking defects observed relate to disease onset based on a combination of electromyography studies, histopathology, and comprehensive gait and kinematic analysis of rodent movement as spasticity and muscle weakness ensues. Furthermore, we will determine mechanisms by which mutations that underlie HSP impact neuronal excitability, again using live cell imaging approaches, but also in vitro biochemistry and genetic studies. Collectively, this work will help to uncover several of the mechanisms that contribute to neuronal dysfunction observed in patients with HSP and lay the foundation for the future development of drug screening approaches.

项目概要 皮质脊髓束内的轴突变性导致多种神经系统疾病，包括 遗传性痉挛性截瘫 (HSP)，这是一组临床和遗传上异质的步态 以平衡不良、痉挛和进行性肌肉无力为特征的疾病，最终可能导致 处于瘫痪状态。利用基于平行动物（大鼠）和诱导多能干细胞（iPSC）的模型，我们的目标是 更好地了解神经退行性疾病引起的病理机制 导致 HSP 的基因突变，长期目标是使用这些模型作为平台来识别新的 对抗疾病的疗法。使用 CRISPR 介导的基因组编辑，我们开发了生理学 重现 HSP 患者表现出的表型的相关模型。具体来说，CRISPR- 表达 SPG4 (spastin) 和 SPG57 (TFG) 病理变异的修饰大鼠表现出早发性 后肢痉挛和共济失调，迅速进展为后肢瘫痪。其他大鼠模型，包括 含有先前在患者中发现的 SPG80 (UBAP1) 截短，表现出晚发疾病表型， 使我们能够在多种独特的背景下检查疾病的进展。我们现在拥有前所未有的 有机会确定所观察到的轴突病的机制基础。特别是，我们计划使用高 分辨率、活细胞共聚焦成像和电子断层扫描来检验以下假设： 特定因子的贩运，包括先前与神经退行性病变有关的神经丝蛋白 疾病，导致 HSP 神经元功能受损。我们还将确定神经丝贩运如何 根据肌电图研究、组织病理学、 并对啮齿动物在发生痉挛和肌肉无力时的运动进行全面的步态和运动学分析。 此外，我们将确定 HSP 突变影响神经元兴奋性的机制， 再次使用活细胞成像方法，而且还进行体外生物化学和遗传学研究。总的来说，这 这项工作将有助于揭示导致患者神经元功能障碍的几种机制 并为未来药物筛选方法的发展奠定基础。