Mechanisms of Target-Specific Axon Regeneration

靶标特异性轴突再生机制

• 批准号: 10610120
• 负责人: Adam James Isabella
• 金额: $ 8.96万
• 依托单位: FRED HUTCHINSON CANCER CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-15 至 2023-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10610120
• 关键词: Address; Adhesives; Affect; Affinity; American; Axon; Back; Biological; Biological Assay; Brain; Cell Adhesion Molecules; Cell surface; Cells; Chemicals; Chemotactic Factors; Chimera organism; Chronic; Clinical; Complex; Connective Tissue; Coupled; Coupling; Cues; Development; Embryo; Environment; Exhibits; Genetic; Goals; Growth; Growth Cones; Health; Human; In Vitro; Injury; Label; Measures; Methods; Modeling; Molecular; Morphology; Motor; Muscle fasciculation; Mutagenesis; Natural regeneration; Nerve; Nerve Fibers; Nerve Regeneration; Neuroglia; Neurons; Outcome; Patients; Pattern; Pharmacology; Positioning Attribute; Process; Property; Recovery; Recovery of Function; Research; Resolution; Sensory; Signal Transduction; Structure; Subgroup; Synapses; System; Techniques; Therapeutic; Therapeutic Intervention; Tissues; Vagus nerve structure; Zebrafish; axon growth; axon injury; axon regeneration; base; cell regeneration; chronic pain; imaging genetics; improved; in vivo; insight; knowledge base; member; motor deficit; mutant; nerve damage; nerve injury; nerve supply; neural patterning; novel; peripheral nerve damage; programs; regenerative; reinnervation; scaffold; therapy development; tissue regeneration; tool; transcriptome sequencing

Project Summary Nerve damage is a common affliction that causes sensory and/or motor deficits. Recovery involves a regenerative process in which damaged axons within a nerve fiber must re-extend to the appropriate target tissues, in a process known as target-specific regeneration. This process often fails in humans, leaving patients with chronic health problems. Improving clinical outcomes requires a better understanding of how target-specific regeneration is regulated. We know that components of the nerve support scaffold can guide axon re-extension along simple paths. However, when axons reach nerve branch points, they require more specific guidance mechanisms to differentiate between multiple paths and select the correct one. We have little understanding of what environmental cues guide these decisions, and how they are appropriately interpreted by regrowing axons. The objective of this proposal is to identify cellular and molecular mechanisms that regulate axon targeting decisions to promote target-specific regeneration. I have established the zebrafish vagus nerve as a model to elucidate mechanisms of target-specific axon regeneration. Regenerating vagus axons select between five nerve branches to robustly re-innervate the correct target tissue, although how they do so is not known. I hypothesize that two non-mutually-exclusive mechanisms regulate target-specific regeneration: 1) chemosensation, in which a regenerating axon can interpret spatially patterned chemical guidance cues in the environment that direct its growth; 2) fasciculation, in which a regenerating axon can recognize undamaged axons that are innervating its intended target and use them as a substrate for directed growth. The three aims of this proposal will comprehensively identify how growing axons interact with their environment at the cell biological and molecular levels during target-specific regeneration. In Aim 1, I will combine a novel single-cell chimera regeneration assay with live imaging and genetic and pharmacological manipulations to establish a conceptual understanding of how in vivo axon-environment interactions guide targeting decisions. In Aim 2, I will combine a novel method to label and isolate live neurons based on their innervation target with in vivo and in vitro techniques to precisely measure how axons of each of the five innervation target groups interact with other axons, and with chemical signals, in the environment. In Aim 3, I will combine innervation target-specific neuron isolation with RNAseq and mutant analysis for unbiased identification of molecules that regulate target selection in each of the five innervation target groups. This study will greatly enhance our fundamental understanding of how axons reinnervate their target tissues during regeneration, and provide an important knowledge base to develop improved treatments for nerve damage.

项目摘要 神经损伤是导致感觉和/或运动缺陷的常见痛苦。恢复涉及a 再生过程，在神经​​纤维内受损的轴突必须重新扩展到适当的目标 组织，在称为目标特异性再生的过程中。这个过程通常在人类中失败，使患者失败 存在慢性健康问题。改善临床结果需要更好地了解目标特定目标 调节再生。我们知道神经支撑支架的组件可以指导轴突重新扩展 沿着简单的路径。但是，当轴突达到神经分支点时，它们需要更具体的指导 区分多个路径并选择正确的机制。我们对 哪些环境提示指导这些决定，以及如何通过再生轴突适当解释它们。 该建议的目的是识别调节轴突靶向的细胞和分子机制 促进目标特异性再生的决定。 我已经建立了斑马鱼迷走神经作为阐明目标特异性轴突机制的模型 再生。再生的迷走轴轴突在五个神经分支之间选择以鲁棒性重新启动正确 靶组织，尽管他们是如何做到的。我假设两种非截然不同的机制 调节目标特异性再生：1）化学敏化，其中再生轴突可以在空间上解释 将化学指导提示在环境中指导其增长； 2）着迷，其中 再生轴突可以识别未损坏的轴突，这些轴突将其预期目标支配并用作 底物定向增长。该提案的三个目标将全面确定轴突的生长方式 在目标特异性再生期间，在细胞生物学和分子水平上与环境相互作用。在 AIM 1，我将将一种新型的单细胞嵌合再生测定法与实时成像和遗传和 药理操作以建立对体内轴突环境的概念理解 互动指导目标决策。在AIM 2中，我将结合一种新颖的方法来标记和分离活神经元 基于它们具有体内和体外技术的神经靶标，以精确测量每个轴突的轴突 五个神经支配目标基团与其他轴突以及化学信号在环境中相互作用。目标 3，我将与RNASEQ和突变体分析结合神经靶靶神经元隔离和无偏的突变体分析 鉴定在五个神经支配靶基组中每个人中调节目标选择的分子。这项研究 将大大增强我们对轴突如何重新构造其目标组织的基本理解 再生，并提供一个重要的知识库，以开发改进的神经损伤治疗方法。