Neuronal regulation of myelination

髓鞘形成的神经元调节

基本信息

批准号：
8546459
负责人：
Roman Jeno Giger
金额：
$ 32.29万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-30 至 2017-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8546459
关键词：
Ablation Actins Acute Adolescent Adult Alleles Autophagocytosis Axon Biochemical Process Biological Preservation Biotinylation Cell Maturation Cell membrane Cells Charcot-Marie-Tooth Disease Coculture Techniques Communication Cuprizone Defect Demyelinating Diseases Development Disease Endocytosis Evaluation Exhibits Foundations Generations Genes Genetic Genetic Models Goals Human Inherited Injection of therapeutic agent Knockout Mice Label Lesion Lipids Lysophosphatidylcholines Lysosomes Mediating Membrane Membrane Proteins Methods Modeling Molecular Molecular Probes Monitor Multiple Sclerosis Mus Mutant Strains Mice Mutate Mutation Myelin Myelin Sheath Nervous System Physiology Nervous system structure Neural Conduction Neuraxis Neuroglia Neurologic Neurons Nodal Oligodendroglia Optic Nerve Pathway interactions Patients Peripheral Peripheral Nervous System Peripheral Nervous System Diseases Phenotype Phosphatidylinositols Phosphoric Monoester Hydrolases Pre-Clinical Model Process Proteins Proteome Proteomics Recycling Regulation Research Retinal Ganglion Cells Sampling Schwann Cells Signal Transduction Simplexvirus Site Spinal Ganglia Staging Stem cells Structure Surface Tamoxifen Testing Transgenic Mice Transgenic Organisms Tremor Two-Dimensional Gel Electrophoresis Vertebrates Vesicle Viral Viral Vector White Matter Disease base cyanine dye 5 gene therapy genetic regulatory protein human disease improved in vivo innovation insight leukodystrophy macromolecule malformation mouse model mutant myelination nervous system disorder novel novel therapeutics preclinical study repaired research study restoration sciatic nerve spinal nerve posterior root trafficking treatment strategy white matter

项目摘要

DESCRIPTION (provided by applicant): In vertebrates, including humans, rapid neuronal communication in the peripheral (PNS) and central nervous system (CNS) is dependent on proper myelination. The myelin-forming cell in the PNS is the Schwann cell (SC) and in the CNS the oligodendrocyte (OL). These specialized cells ensheath neuronal processes and thereby facilitate rapid propagation of electrical impulses. PNS myelin is defective in several types of Charcot-Marie-Tooth (CMT) disease, one of the most common inherited neurological disorders. Abnormal development of myelin in the CNS results in disorders known as leukodystrophies. We previously described the severe peripheral neuropathy CMT4J, caused by mutation of the human FIG4/SAC3 gene encoding an evolutionarily conserved lipid phosphatase that regulates intracellular vesicle trafficking along the endo-lysosomal pathway. The main objectives of our research are to understand the molecular mechanisms by which FIG4 deficiency disrupts myelin formation, and to develop treatment strategies for CMT4J in a preclinical model. Mutant mice with global loss of Fig4 expression (Fig4-/-) exhibit dramatic reduction of myelin in the CNS and PNS, severe tremor, and juvenile lethality. Electrophysiological recordings revealed slowed conduction of electrical impulses in sciatic and optic nerves. Surprisingly, the myelin defects in Fig4-/- mice can be "rescued" by neuron-specific expression of wildtype Fig4. Based on these observations, we hypothesize that loss of Fig4 disrupts neuron-specific signaling mechanisms required for myelination. In Specific Aim 1 and Aim 2 we use a combination of mouse genetics and proteomics to identify the neuronal myelination signals that are disrupted in Fig4 mutant mice and to determine the temporal requirement for Fig4 in vivo. These experiments will provide new mechanistic insights into the neuronal signals that direct myelinogenesis. To model human CMT4J, we developed transgenic mice that ubiquitously express low levels of the human disease allele Fig4-I41T on a Fig4-/- background (CMT4J mice). These mice exhibit hypomyelination comparable to that of Fig4-/- mice, but survive to adulthood with many neurologic features of the human disease. Since we have shown that transgenic expression of Fig4 in neurons is sufficient to drive myelination, we propose a gene therapy study in Specific Aim 3. Dorsal root ganglion neurons (PNS) and retinal ganglion cells (CNS) of CMT4J mice will be transduced with viral vectors to express wildtype Fig4. Myelination, nodal structure, and nerve conduction velocity in sciatic or optic nerve will be monitored as indicators of efficacy. Restoration of myelination by Fig4 gene therapy in mice would demonstrate a new therapeutic avenue for patients suffering from myelination disorders.

描述（由申请人提供）：在包括人类在内的脊椎动物中，周围（PNS）和中枢神经系统（CNS）中的快速神经元通信取决于适当的髓鞘化。 PNS中的髓磷脂形成细胞是Schwann细胞（SC）和CNS中的少突胶质细胞（OL）。这些专门的细胞围绕神经元过程，从而促进电脉冲的快速传播。 PNS髓磷脂在几种类型的Charcot-Marie-Tooth（CMT）疾病中有缺陷，这是最常见的遗传性神经系统疾病之一。中枢神经系统中髓磷脂的异常发育会导致疾病称为白细胞营养不良。我们先前描述了严重的周围神经病CMT4J，这是由人体FIG4/SAC3基因的突变引起的，该基因编码了一种进化保守的脂质磷酸酶，该脂质磷酸酶调节沿着内溶液途径的细胞内囊泡运输。我们研究的主要目标是了解FIF4缺乏症会破坏髓磷脂形成的分子机制，并在临床前模型中制定CMT4J的治疗策略。具有FIG4表达全球损失的突变小鼠（FIG4 - / - ）在中枢神经系统和PNS中表现出明显的髓磷脂，严重的震颤和少年致死性。电生理记录显示，坐骨神经和视神经中电脉冲的传导减慢。令人惊讶的是，FIG4 - / - 小鼠中的髓磷脂缺陷可以被野生型FIG4的神经元特异性表达“拯救”。基于这些观察结果，我们假设FIG4的损失破坏了髓鞘形成所需的神经元特异性信号传导机制。在特定的目标1和AIM 2中，我们使用小鼠遗传学和蛋白质组学的组合来识别在FIF4突变小鼠中破坏的神经元髓鞘信号，并确定体内Fig4的时间需求。这些实验将为指导髓质生成的神经元信号提供新的机械见解。为了建模人类CMT4J，我们开发了转基因小鼠，这些小鼠普遍于FIG4 - / - 背景（CMT4J小鼠）上表达低水平的人类疾病等位基因FIG4-I41T。这些小鼠表现出与图4-/ - 小鼠相当的低髓性，但具有人类疾病的许多神经系统特征的成年。由于我们已经表明，神经元中图4的转基因表达足以驱动髓鞘化，因此我们提出了一项基因疗法研究3.特定目标3。背根神经节神经元（PNS）和视网膜神经节细胞（CNS）和CMT4J小鼠的视网膜神经节细胞（CNS），将用病毒转导表达野生型fig4的向量。坐骨神经或视神经中的髓鞘化，淋巴结结构和神经传导速度将被监测为功效的指标。在小鼠中通过FIG4基因疗法恢复髓鞘化，将为患有髓鞘疾病的患者提供新的治疗途径。