The role of mTOR signaling in oligodendrocyte differentiation and CNS myelination

mTOR信号在少突胶质细胞分化和中枢神经系统髓鞘形成中的作用

• 批准号: 8667345
• 负责人: WENDY B MACKLIN
• 金额: $ 63.1万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-30 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8667345
• 关键词: Address; Adult; Area; Coculture Techniques; Complex; Cultured Cells; Data; Demyelinating Diseases; Demyelinations; Development; Disease; Elements; Event; Human; In Vitro; Laboratories; Literature; Maintenance; Mediating; Molecular; Multiple Sclerosis; Mus; Mutant Strains Mice; Myelin; Neuraxis; Oligodendroglia; Pathway interactions; Proteins; Proteome; Proteomics; Raptors; Reagent; Regulation; Research; Role; Signal Pathway; Signal Transduction; Sirolimus; TSC1/2 gene; Techniques; Testing; Time; Tissue-Specific Gene Expression; Tissues; Wood material; design; human FRAP1 protein; in vivo; mTOR inhibition; myelination; nervous system development; overexpression; programs; remyelination; repaired

DESCRIPTION (provided by applicant): The current studies are a multiple-P.I. proposal that focuses on the role of mTOR in oligodendrocyte development and CNS myelination. This is an important research area because of the devastating consequences of demyelination in humans and the need to understand the molecular details of how myelination and remyelination are regulated, in order to repair such damage. The Macklin laboratory has investigated the role of Akt and mTOR in CNS myelination, while the Wood laboratory has investigated the role of mTOR in oligodendrocyte differentiation and has identified an mTOR-regulated proteome in oligodendrocytes. There is inconsistency in the literature and in the preliminary data from the two laboratories as to when in the developmental program of oligodendrocytes mTOR becomes a major regulator. Thus, the current proposal is designed to answer unequivocally when and how the mTOR signaling complexes regulate oligodendrocyte development including potential actions on both differentiation and myelination. Rather than compete to address these questions, we propose a collaborative project using complementary mouse lines, and standardized reagents and techniques. The two laboratories have complementary sets of conditional mutant mice that will be used collaboratively to investigate these questions. In the first specific aim, we will investigate the mechanisms by which mTOR regulates oligodendrocyte differentiation, testing the hypothesis that mTOR directly regulates oligodendrocyte differentiation via specific actions of both mTORC1 and mTORC2. This will be investigated by studying the signaling pathways and the differentiation events that are modulated in mTOR, raptor or rictor conditionally-deleted mice. In the second specific aim, we will investigate the mechanisms by which mTOR regulates CNS myelination and myelin maintenance. We will test the hypothesis that mTOR directly regulates myelination via both mTORC1 and mTORC2, with differential control by each complex. Studies will additionally investigate how active myelination shifts to myelin maintenance in the CNS. In the third specific aim, we will investigate the upstream regulation of the two mTOR complexes by TSC1/2 in developing oligodendrocytes. These studies will test the hypothesis that TSC signaling regulates oligodendrocyte differentiation and CNS myelination through upstream inhibition of mTORC1 and activation of mTORC2. TSC1/2 are considered to be negative regulators of mTOR signaling, yet in some contexts loss of TSC activity induces hypomyelination rather than the expected hypermyelination. Establishing how they impact mTOR signaling in the oligodendrocyte is therefore important. In the final aim, we will determine the mechanisms by which the mTOR pathway regulates remyelination. The crucial questions in this aim will be whether the role of this pathway in the regulation of oligodendrocyte differentiation and myelination recapitulates its function during development, or whether there are unique elements of mTOR regulation of remyelination in adult tissue. This aim clearly has significant impact on our understanding of remyelination in multiple sclerosis.

描述（由申请方提供）：当前研究是一项多P.I.该提案侧重于mTOR在少突胶质细胞发育和CNS髓鞘形成中的作用。这是一个重要的研究领域，因为人类脱髓鞘的破坏性后果，以及需要了解髓鞘形成和髓鞘再生如何调节的分子细节，以修复这种损伤。Macklin实验室研究了Akt和mTOR在CNS髓鞘形成中的作用，而Wood实验室研究了mTOR在少突胶质细胞分化中的作用，并鉴定了少突胶质细胞中mTOR调节的蛋白质组。在文献和来自两个实验室的初步数据中，关于在少突胶质细胞的发育程序中，mTOR何时成为主要调节因子存在不一致。因此，目前的建议旨在明确回答mTOR信号复合物何时以及如何调节少突胶质细胞发育，包括对分化和髓鞘形成的潜在作用。 而不是竞争来解决这些问题，我们提出了一个合作项目，使用互补的小鼠品系，标准化的试剂和技术。这两个实验室有互补的条件突变小鼠，将用于合作研究这些问题。在第一个具体目标中，我们将研究mTOR调节少突胶质细胞分化的机制，检验mTOR通过mTORC 1和mTORC 2的特异性作用直接调节少突胶质细胞分化的假设。这将通过研究在mTOR、raptor或rictor条件性缺失小鼠中调节的信号传导途径和分化事件来研究。在第二个具体目标中，我们将研究mTOR调节CNS髓鞘形成和髓鞘维持的机制。我们将检验mTOR通过mTORC 1和mTORC 2直接调节髓鞘形成的假设，每个复合物具有差异控制。研究还将调查中枢神经系统中活跃的髓鞘形成如何转变为髓鞘维持。在第三个具体目标中，我们将研究在发育中的少突胶质细胞中TSC 1/2对两种mTOR复合物的上游调控。这些研究将检验TSC信号通过上游抑制mTORC 1和激活mTORC 2调节少突胶质细胞分化和CNS髓鞘形成的假设。TSC 1/2被认为是mTOR信号传导的负调节剂，然而在某些情况下，TSC活性的丧失诱导髓鞘形成不足而不是预期的髓鞘形成过度。因此，确定它们如何影响少突胶质细胞中的mTOR信号传导是重要的。在最后的目标，我们将确定mTOR途径调节髓鞘再生的机制。这一目标的关键问题是，这一途径在调节少突胶质细胞分化和髓鞘形成中的作用是否重演了它的作用。 在发育过程中的功能，或是否有独特的元件mTOR调节髓鞘再生成人组织。这个目标显然对我们理解多发性硬化的髓鞘再生有重大影响。