Novel mechanisms of growth cone guidance

生长锥引导的新机制

基本信息

批准号：
8098348
负责人：
Michele Lynn Lemons
金额：
$ 18.77万
依托单位：
ASSUMPTION COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-04-01 至 2015-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8098348
关键词：
Academic Research Enhancement Awards Adult Afferent Neurons Affinity Axon Behavior Binding Biochemical Biological Assay Blocking Antibodies Cell Adhesion Molecules Chemicals Co-Immunoprecipitations Complex Cues Cytoplasmic Tail Data Data Reporting Destinations Development Disease Embryo Environment Extracellular Matrix Failure Figs - dietary Growth Cones Injury Integrin Binding Integrins Knowledge Lead Ligands Mediating Mediator of activation protein Mental Retardation Molecular Molecular Conformation Motor Nervous system structure Neurons Paralysed Pathway interactions Peptide antibodies Peptides Play Process Protein Region Publications Research Role Sensory Series Signaling Molecule Small Interfering RNA Spinal Ganglia Spinal cord injury Stroke Structure Students Techniques Testing Thinking Training Western Blotting Work axon guidance axon regeneration axonal guidance cognitive function extracellular human NTN1 protein induced pluripotent stem cell insight laminin-1 nervous system development netrin receptor netrin-1 netrin-2 netrin-3 novel receptor receptor expression research study response skills therapy design/development

项目摘要

DESCRIPTION (provided by applicant): Growth cones are highly specialized structures located at the tips of axons that integrate a complex concert of chemical cues to guide axons to their appropriate destinations. This extraordinary navigational ability of growth cones is essential for proper formation of the nervous system. Aberrant axonal projections are thought to contribute to conditions such as mental retardation. Furthermore, the failure of damaged adult axons to re-navigate to their targets after spinal cord injury or stroke contributes to paralysis and/or compromised motor, sensory and cognitive function. Therefore, a better understanding of growth cone navigation will contribute to treatment of these conditions. For this reason, it is essential to understand the extracellular ligands, as well as their receptors, that direct growth cone guidance. While growth cone ligand-receptor complexes are beginning to be unraveled, significant gaps in our knowledge still exist. In this proposal, we investigate the relationship between the axon guidance molecule netrin-1 and integrin receptors in chick sensory neurons. While netrin-1 has many known receptors, these studies are the first to highlight integrins as possible netrin-1 receptors and as mediators of netrin-induced growth cone behaviors, such as collapse. Our preliminary data suggest that two integrin subunits ( 3, 6) are involved in netrin-induced growth cone collapse. Moreover, our data show that netrin-1 causes integrin activation (a conversion to a high ligand affinity conformational state). These data are exciting because they suggest that integrin receptors, well known for their ability to interact with extracellular matrix molecules, may also interact with the axon guidance molecule, netrin-1 and play a role in netrin-mediated growth cone behaviors. In Aim 1 we will we use siRNA, function blocking antibodies and competitive peptides to individually test the involvement of all known integrin subunits on netrin-induced growth cone collapse. These experiments will provide a profile of neuronal integrin subunits required for netrin- mediated collapse. In Aims 2 and 3, we will examine if the integrin-netrin interaction is direct and/or indirect. In Aim 2, we will use co-immunoprecipitations and affinity columns to determine if netrin-1 directly binds to integrin receptors. This aim will determine if integrins may serve as netrin receptors. In Aim 3, we will determine if traditional netrin receptors mediate an integrin-netrin interaction. More specifically, we will use siRNA to investigate if traditional netrin receptors are involved in netrin-induced integrin activation. These studies will reveal an indirect integrin-netrin relationship. Aims 2 and 3 are not mutually exclusive; netrin-1 may interact with integrins in both a direct (Aim 2) and indirect (Aim 3) manner. This research will provide an excellent training opportunity for undergraduates as they acquire the skills of scientific thinking and engage in all aspects of scientific research. Furthermore, these studies will establish the relationship between netrin-1 and integrin receptors as well as the impact of this relationship on growth cone guidance. These results will provide new insights into the role of integrin receptors in netrin-mediated growth cone repulsive behaviors. PUBLIC HEALTH RELEVANCE: The ability of millions of neurons to accurately navigate their axonal projections through a complex extracellular environment to reach their appropriate targets is essential for proper formation of the nervous system and yet the mechanisms of this navigation are not fully understood. We propose to investigate the role of cell adhesion molecules, integrin receptors, in the navigational abilities of neurons in response to an extracellular guidance molecule, netrin-1.These studies will provide fundamental insights into the mechanisms of axonal guidance and are expected to ultimately lead to the development of new therapies for the treatments of spinal cord injuries or disorders arising from deficiencies in this process.

描述（由申请人提供）：生长锥是位于轴突尖端的高度专业化的结构，它整合了一系列复杂的化学信号，以引导轴突到达适当的目的地。生长锥的这种非凡的导航能力对于神经系统的正确形成至关重要。异常的轴突投射被认为会导致智力低下等病症。此外，脊髓损伤或中风后受损的成人轴突无法重新导航至目标，导致瘫痪和/或运动、感觉和认知功能受损。因此，更好地了解生长锥导航将有助于治疗这些疾病。因此，了解指导生长锥引导的细胞外配体及其受体至关重要。虽然生长锥配体-受体复合物已开始被阐明，但我们的知识仍然存在重大差距。在本提案中，我们研究了鸡感觉神经元中轴突引导分子 netrin-1 和整合素受体之间的关系。虽然 netrin-1 有许多已知的受体，但这些研究首次强调整合素可能是 netrin-1 受体以及作为 netrin 诱导的生长锥行为（例如塌陷）的介质。我们的初步数据表明，两个整合素亚基（3、6）参与了 netrin 诱导的生长锥塌陷。此外，我们的数据表明 netrin-1 会引起整合素激活（向高配体亲和力构象状态的转化）。这些数据令人兴奋，因为它们表明，以与细胞外基质分子相互作用的能力而闻名的整联蛋白受体也可能与轴突引导分子 netrin-1 相互作用，并在 netrin 介导的生长锥行为中发挥作用。在目标 1 中，我们将使用 siRNA、功能阻断抗体和竞争性肽来单独测试所有已知整合素亚基对 netrin 诱导的生长锥塌陷的影响。这些实验将提供 netrin 介导的崩溃所需的神经元整合素亚基的概况。在目标 2 和 3 中，我们将检查整合素-netrin 相互作用是否是直接和/或间接的。在目标 2 中，我们将使用免疫共沉淀和亲和柱来确定 netrin-1 是否直接与整合素受体结合。这一目标将确定整合素是否可以充当 netrin 受体。在目标 3 中，我们将确定传统 netrin 受体是否介导整合素-netrin 相互作用。更具体地说，我们将使用 siRNA 来研究传统 netrin 受体是否参与 netrin 诱导的整合素激活。这些研究将揭示整合素-netrin 的间接关系。目标 2 和 3 并不相互排斥； netrin-1 可能以直接（目标 2）和间接（目标 3）方式与整合素相互作用。这项研究将为本科生获得科学思维技能和从事科学研究的各个方面提供极好的培训机会。此外，这些研究将建立 netrin-1 和整合素受体之间的关系，以及这种关系对生长锥引导的影响。这些结果将为整合素受体在 netrin 介导的生长锥排斥行为中的作用提供新的见解。公共健康相关性：数以百万计的神经元能够通过复杂的细胞外环境准确导航其轴突投射以到达适当的目标，这对于神经系统的正确形成至关重要，但这种导航的机制尚未完全了解。我们建议研究细胞粘附分子、整合素受体在神经元响应细胞外引导分子 netrin-1 的导航能力中的作用。这些研究将为轴突引导机制提供基本见解，并有望最终引导开发新疗法来治疗脊髓损伤或由于这一过程的缺陷而引起的疾病。