Cytoskeletal Regulation During Growth Cone Migration and Axon Guidance

生长锥迁移和轴突引导过程中的细胞骨架调节

基本信息

批准号：
7582045
负责人：
FRANK B GERTLER
金额：
$ 28.56万
依托单位：
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-08-01 至 2012-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7582045
关键词：
Actins Adult Afferent Neurons Animals Axon Behavior Binding Binding Proteins Biochemical Biological Biological Assay Brain Caenorhabditis elegans Cell Surface Receptors Cells Complex Cues Cytoskeleton Data Defect Development Disease Electron Microscopy Electroporation Employee Strikes Enterobacteria phage P1 Cre recombinase Environment Exhibits F-Actin Fetal Development Filopodia Fingers Genetic Goals Growth Cones In Vitro Injury Knock-out Knockout Mice Laboratory Finding Lead Learning Life Link Locomotion Mediating Microtubule Stabilization Microtubules Molecular Monitor Morphology Movement Mus Mutation Nerve Nerve Fibers Nervous System Trauma Nervous system structure Neuraxis Neurites Neurons Orthologous Gene Pathway interactions Phenotype Phosphatidylinositols Phosphorylation Site Play Positioning Attribute Preparation Primary Cell Cultures Process Protein Family Proteins RAS Superfamily Proteins RNA Interference RNAi vector Regulation Research Resolution Role Sampling Signal Pathway Signal Transduction Spinal Ganglia Structure System Testing Vertebral column Work axon growth axon guidance axonal guidance base cellular imaging central nervous system injury extracellular human NTN1 protein in utero insight interest knock-down loss of function migration mutant nervous system development netrin-1 polymerization protein complex protein function public health relevance receptor repaired response restoration therapeutic development therapy design therapy development vasodilator-stimulated phosphoprotein

项目摘要

DESCRIPTION (provided by applicant): Damage to connections within the adult Central Nervous System (CNS) by injury or disease is often irreparable. To design therapies to repair CNS damage requires a detailed understanding of the cellular mechanisms underlying CNS development. As the brain matures, neurons migrate to their proper positions within the brain and elaborate processes that are guided to their targets to form proper connections. Both initial formation of growth cone-tipped neurites, and subsequent guided locomotion of axonal growth cones, require F-actin and microtubule (MT) dynamics. F-actin:MT interactions likely play key roles in both of these processes. However, the molecular mechanisms that mediate such interactions, and how these interactions drive neuritogenesis and axon guidance, are not understood. Ena/VASP proteins function in growth cone guidance by controlling actin cytoskeleton dynamics. Using a combination of mouse genetics, primary cell culture, live cell imaging and electron microscopy, my lab found that Ena/VASP-deficient cortical neurons fail to form filopodia, finger-like processes comprised of bundled F-actin. Furthermore, we found that cortical neurons devoid of filopodia fail to form neurites, and exhibit altered microtubule dynamics. Restoration of filopodia in Ena/VASP mutant cortical neurons also rescues neurite initiation. Preliminary data indicate that Ena/VASP-deficient sensory neurons form axons, but exhibit striking guidance defects. We will use sensory neuron preparations from Ena/VASP deficient animals to test our working hypothesis is that Ena/VASP- dependent filopodia formation enables interactions between MTs and actin bundles that are required to receive both attractive and repulsive cues. Additional new data indicate that Ena/VASP proteins may act to coordinate F-actin:MT interactions, and that the TRIM9 protein interacts with both Ena/VASP and microtubules; TRIM9 is also implicated in the control of axon navigation. Furthermore, a network of proteins, including Ena/VASP, is likely regulated by Lamellipodin, a molecule that integrates signals generated by cell-surface receptors for axonal guidance factors. Collectively, these data lead us to hypothesize that Ena/VASP proteins participate in protein networks that play key roles in F-actin: MTs interactions, and are in turn linked to signaling pathways controlled by guidance receptors. Our long-term goal is to understand how neurons integrate environmental cues to orchestrate changes in their morphology and movement necessary to establish a functional nervous system. A better understanding of the mechanistic basis of neurite formation and axon guidance will provide fundamental insight into how connections in the nervous system are established and how they are remodeled during plasticity. The results of our research plan should be of great value to the development of therapeutic approaches to repair these connections subsequent to disease or injury. PUBLIC HEALTH RELEVANCE: Damage to the nerves that form connections within the adult brain and spinal column by injury or disease is often irreparable. We seek a comprehensive understanding of how nerve fibers form and are guided to their targets initially during fetal development expecting that this will help us learn to repair damage to the brain.

描述（由申请人提供）：受伤或疾病对成人中枢神经系统（CNS）内部连接的损害通常是无法弥补的。为了设计修复中枢神经系统损伤的疗法，需要详细了解中枢神经系统开发的细胞机制。随着大脑的成熟，神经元迁移到大脑中的适当位置，并详细的过程被引导到目标以形成适当的连接。生长锥神经突的初始形成，以及随后的轴突生长锥的引导运动，都需要F-肌动蛋白和微管（MT）动力学。 F-肌动蛋白：MT相互作用可能在这两个过程中起关键作用。但是，尚不清楚介导这种相互作用的分子机制，以及这些相互作用如何驱动神经发生和轴突引导。通过控制肌动蛋白细胞骨架动力学，ENA/VASP蛋白在生长锥引导中的功能。使用小鼠遗传学，原代细胞培养，活细胞成像和电子显微镜的结合，我的实验室发现ENA/VASP缺陷的皮质神经元无法形成丝状神经元，由捆绑的F-肌动蛋白组成的手指样过程。此外，我们发现没有丝状神经元的皮质神经元无法形成神经突，并且表现出改变的微管动力学。 ENA/VASP突变性皮质神经元中丝状疾病的恢复也挽救了神经突的启动。初步数据表明，ENA/VASP缺陷的感觉神经元形成轴突，但表现出引人注目的引导缺陷。我们将使用ENA/VASP缺乏动物的感觉神经元制剂来测试我们的工作假设，即ENA/VASP-依赖性丝状疾病的形成可以使MTS与肌动蛋白束之间的相互作用，这些丝网和肌动蛋白束需要获得有吸引力和排斥的提示。其他新数据表明，ENA/VASP蛋白可以起作用以协调F-肌动蛋白：MT相互作用，并且Trim9蛋白与ENA/VASP和微管相互作用。 TRIM9还与轴突导航的控制有关。此外，包括ENA/VASP在内的蛋白质网络很可能受lamellipodin的调节，lamellipodin是一种整合由细胞表面受体产生的信号来用于轴突引导因素。总的来说，这些数据使我们假设ENA/VASP蛋白参与了在F-肌动蛋白中起关键作用的蛋白质网络：MTS相互作用，并且又与指导受体控制的信号通路有关。我们的长期目标是了解神经元如何整合环境线索以策划建立功能性神经系统所必需的形态和运动的变化。更好地理解神经突的机理基础和轴突指导将提供有关神经系统中如何建立联系以及在可塑性期间如何重塑的基本见解。我们的研究计划的结果对于修复疾病或受伤后的治疗方法的发展应该具有很大的价值。公共卫生相关性：受伤或疾病在成人大脑和脊柱内形成连接的神经的损害通常是无法弥补的。我们寻求对神经纤维如何形成的全面理解，并在胎儿发育期间最初被引导到其目标，这将有助于我们学习修复对大脑的损害。