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: 8894104
• 负责人: WENDY B MACKLIN
• 金额: $ 69.85万
• 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 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8894104
• 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（由申请人提供）：当前的研究是多 P.I.该提案重点关注 mTOR 在少突胶质细胞发育和中枢神经系统髓鞘形成中的作用。这是一个重要的研究领域，因为脱髓鞘对人类造成了毁灭性的后果，并且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。关于 mTOR 在少突胶质细胞发育过程中何时成为主要调节因子，文献和两个实验室的初步数据存在不一致。因此，当前的提议旨在明确回答 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。 我们没有竞相解决这些问题，而是提出了一个使用互补小鼠系以及标准化试剂和技术的合作项目。这两个实验室拥有互补的条件突变小鼠组，将共同使用它们来研究这些问题。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 mTORC1 和 mTORC2 的特定作用直接调节少突胶质细胞分化的假设。这将通过研究 mTOR、raptor 或 rictor 条件缺失小鼠中调节的信号通路和分化事件来进行研究。在第二个具体目标中，我们将研究 mTOR 调节中枢神经系统髓鞘形成和髓磷脂维持的机制。我们将测试 mTOR 通过 mTORC1 和 mTORC2 直接调节髓鞘形成的假设，并由每个复合体进行差异控制。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的维持。在第三个具体目标中，我们将研究少突胶质细胞发育过程中 TSC1/2 对两个 mTOR 复合物的上游调节。这些研究将检验 TSC 信号传导通过上游 mTORC1 抑制和 mTORC2 激活调节少突胶质细胞分化和 CNS 髓鞘形成的假设。 TSC1/2 被认为是 mTOR 信号传导的负调节因子，但在某些情况下，TSC 活性的丧失会导致髓鞘形成不足，而不是预期的髓鞘形成过多。因此，确定它们如何影响少突胶质细胞中的 mTOR 信号传导非常重要。最终目标是确定 mTOR 通路调节髓鞘再生的机制。这一目标的关键问题是该途径在少突胶质细胞分化和髓鞘形成调节中的作用是否重现了它的作用。 发育过程中的功能，或者是否存在 mTOR 调节成人组织髓鞘再生的独特元件。这一目标显然对我们对多发性硬化症髓鞘再生的理解产生了重大影响。