Genetic dissection of peripheral glia and glial sheath development

外周胶质细胞和胶质鞘发育的遗传解剖

• 批准号: RGPIN-2014-04511
• 负责人: Auld, Vanessa
• 金额: $ 3.42万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=566567
• 关键词: Genetic; dissection; peripheral; glia; glial

Overview: The long-term goal of my research program is to study the protein interactions that underlies the development of the glial sheath that ensheaths and insulates the peripheral nerve. The peripheral nerve responds to environment cues and controls muscle contraction and are surrounded by layers of glial cells, the major insulator of the nervous system. The formation of a glial sheath around axons is an essential component of the development and function of the nervous system in all animals. Little is known about the mechanisms that trigger glial cells to migrate along and then wrap their associated axons. Both glial migration and the formation of the glial wrap around axons involves protein adhesion and communication between cells leading to extensive rearrangements of the cytoskeleton. Glial cells must differentiate from elongated migrating cells into cells with elaborate extensions that encompass the axons they wrap. In Drosophila three distinct glial layers contribute to the mature peripheral nerve. In later stages the glial sheath must be maintained and expand to match animal growth to ensure complete insulation of the underlying axons. Loss of the glial sheath leads to a disruption of neuronal function and lethality. Our previous work funded by NSERC has shown that a class of adhesion proteins called the integrins and their binding partners within the cell play a critical role in establishing and maintaining the glial sheath. We found that integrin communication between the distinct glia layers in the peripheral nervous system (PNS) is critical to maintain glia function and insulating glia wrap. But how the integrin complex functions to control glia sheath formation is not known. We have evidence within the core of the peripheral nerve, integrin mediated adhesion is not through extracellular matrix components but rather through membrane bound ligands. Our investigation of potential integrin ligands identified Basigin, a transmembrane Ig domain protein, as critical for glia-glial adhesion to maintain the glial wrap and the glial layers. Our NSERC funded research has also uncovered a critical role of the gap junction protein, Innexin 2, in the development or maintenance of the glial sheath and these data also point to an essential role for glia-glia communication. But how Innexin 2 contributes to sheath formation either as a gap junction or an adhesion protein is not known. Therefore our research program is consolidating on the central theme that the development and maintenance of the glia sheath around axons is a function of not just of glia to axon communication but also of glia to glia communication. Our short terms goals will address the mechanisms that underlie this communication. Approach: My laboratory has extensive experience analyzing the molecules and developmental dynamics of the glia of the peripheral nervous system using a combination of molecular and cell biology paired with high resolution imaging. We have generated a collection of cellular and genetic markers that allow us to manipulate the genes expressed in the peripheral glia and then assess the results during the development. Therefore we can use the Drosophila model system to isolate and characterize the global fundamental mechanisms that underlie glial cell development and sheath formation in all animals. Objectives: We will investigate the molecular mechanisms that underlie integrin mediated glial sheath formation and maintenance, and the role of the Ig domain proteins including Basigin in this process. We will use a loss of function and rescue approach to determine how innexin 2 functions in the glial sheath, as a gap junction and through what signaling mechanism.

概述：我的研究计划的长期目标是研究蛋白质相互作用，该蛋白质相互作用是胶质鞘开发的基础，该胶质鞘的开发和隔离神经。周围神经对环境线索的反应并控制肌肉收缩，并被神经胶质细胞的层（神经系统的主要绝缘子）包围。轴突周围的神经胶质鞘形成是所有动物神经系统发育和功能的重要组成部分。关于触发神经胶质细胞沿迁移然后包裹相关轴突的机制知之甚少。神经胶质迁移和轴突周围的神经胶质包裹的形成都涉及蛋白质粘附和细胞之间导致细胞骨架广泛重排的通讯。神经胶质细胞必须从延伸的迁移细胞中区分出涵盖其包裹的轴突的精细延伸效应。在果蝇中，三个不同的神经胶质层有助于成熟的外周神经。在后来的阶段，必须保持神经胶鞘并扩展以匹配动物的生长，以确保完全绝缘的轴突。神经胶质鞘的丧失会导致神经元功能和致死性的破坏。我们以前由NSERC资助的工作表明，一类称为整联蛋白及其结合伴侣在细胞中的粘附蛋白在建立和维持神经胶质鞘中起着至关重要的作用。我们发现，周围神经系统（PNS）中不同神经胶质层之间的整合素通信对于维持胶质功能和绝缘胶质包裹至关重要。但是，尚不清楚整合素复合物如何控制神经胶质鞘形成。我们有周围神经核心的证据，整联蛋白介导的粘附不是通过细胞外基质成分，而是通过膜结合的配体。我们对潜在整联蛋白配体的研究确定了跨膜Ig结构蛋白Basigin，对于维持神经胶质包裹和神经胶质层的神经胶质粘附至关重要。我们的NSERC资助的研究还发现了间隙连接蛋白Innexin 2在开发或维持神经胶质鞘中的关键作用，这些数据也表明了Glia-Glia通信的重要作用。但是，不知道Innexin 2作为间隙连接或粘附蛋白的鞘形成如何促进鞘形成。因此，我们的研究计划正在整合一个中心主题，即轴突周围的神经胶质鞘的开发和维护不仅是胶质传播到轴突通信的函数，而且是神经胶质通信的胶质函数。我们的短期目标将解决基于这种交流的机制。方法：我的实验室拥有丰富的经验，分析了外周神经系统神经胶质的分子和发育动力学，并结合了分子和细胞生物学与高分辨率成像搭配。我们已经产生了一系列细胞和遗传标记，使我们能够操纵在外周胶质神经胶质中表达的基因，然后在发育过程中评估结果。因此，我们可以使用果蝇模型系统来隔离和表征所有动物的神经胶质细胞发育和鞘形成的全球基本机制。目的：我们将研究整合素介导的神经胶质鞘形成和维护的分子机制，以及包括Basigin在此过程中的IG结构域蛋白的作用。我们将使用功能和救援方法的丧失来确定Innexin 2在神经胶质鞘中的功能如何作为间隙连接以及通过什么信号传导机制。