Mechanisms of Target-Specific Axon Regeneration

靶标特异性轴突再生机制

基本信息

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
项目类别：
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

项目摘要

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.

项目概要神经损伤是一种常见的疾病，会导致感觉和/或运动缺陷。恢复涉及再生过程，神经纤维内受损的轴突必须重新延伸到适当的目标组织，这一过程称为目标特异性再生。这个过程在人类身上经常失败，导致患者患有慢性健康问题。改善临床结果需要更好地了解目标特异性如何再生受到调节。我们知道神经支撑支架的组件可以引导轴突重新延伸沿着简单的路径。然而，当轴突到达神经分支点时，它们需要更具体的引导区分多条路径并选择正确路径的机制。我们对此知之甚少哪些环境因素指导着这些决定，以及轴突再生如何适当地解释这些决定。该提案的目的是确定调节轴突靶向的细胞和分子机制促进特定目标再生的决策。我建立了斑马鱼迷走神经作为模型来阐明目标特异性轴突的机制再生。再生迷走神经轴突在五个神经分支之间进行选择，以强有力地重新支配正确的神经分支目标组织，尽管它们如何做到这一点尚不清楚。我假设两种非互斥机制调节目标特异性再生：1）化学感觉，其中再生轴突可以在空间上解释环境中引导其生长的化学引导线索； 2) 肌束震颤，其中再生轴突可以识别未受损的轴突，这些轴突正在刺激其预期目标，并将它们用作定向生长的基质。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过程中，它们在细胞生物学和分子水平上与环境相互作用。在目标 1，我将把一种新型单细胞嵌合体再生测定与实时成像和遗传和药理学操作以建立对体内轴突环境如何的概念性理解互动指导目标决策。在目标 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他们的神经支配目标，利用体内和体外技术来精确测量每个轴突的情况五个神经支配目标组与环境中的其他轴突和化学信号相互作用。瞄准 3，我将把神经支配目标特异性神经元分离与RNAseq和突变体分析结合起来，以实现无偏识别调节五个神经支配目标组中每个目标选择的分子。这项研究将极大地增强我们对轴突如何重新支配其目标组织的基本理解再生，并为开发神经损伤的改进治疗方法提供重要的知识基础。