Peripheral Glial Response to Sensory Nerve Degeneration

 描述(申请人提供)：本项目的重点是包裹大多数感觉神经轴突的外围非髓鞘胶质细胞。在神经疾病中，无髓鞘轴突经常受损和/或丢失。非髓鞘胶质细胞被认为在受影响神经的修复、退化和/或再生中发挥关键作用。我们选择关注感觉神经轴突退化的反应，这是许多神经疾病的共同特征。为了更好地了解神经胶质细胞对轴突损伤/退变的反应机制，我们建立了斑马鱼周围感觉神经退行性变的诱导性模型。该模型允许有条件地和选择性地消融周围感觉神经元及其轴突。在我们的初步研究中，我们发现有证据表明，在轴突变性时，外周神经胶质细胞对于轴突碎片的清除和免疫细胞向受累神经部位的招募至关重要。将在这一提议中检验的假设是，轴突损伤和退化诱导神经胶质细胞改变其基因表达，导致吞噬行为并向免疫系统发出信号。在这个应用中，我们提出了两个目标：(1)识别与周围神经胶质细胞对感觉神经退化的反应有关的基因；(2)验证目标1中确定的候选基因。这将通过对对照和甲硝唑处理的鱼的转录组分析来实现。候选基因的验证将使用qPCR、原位杂交和CRISPR/Cas9介导的缺失分析。相关基因的鉴定将为未来研究外周神经胶质细胞对感觉回路死亡和退化的反应机制提供重要的基础，并可作为高等脊椎动物定向研究的起点，最终目标是在临床上开发新的方向来治疗许多衰弱的感觉神经病。

 DESCRIPTION (provided by applicant): The focus of this project is the peripheral non-myelinating glia that ensheath the majority of sensory axons. Unmyelinated axons are often damaged and/or lost in neuropathies. The non-myelinating glia are thought to play key roles in the repair, degeneration and/or regeneration of the affected nerves. We have chosen to focus on the response to degeneration of sensory axons, one feature common to many neuropathies. To gain a better understanding of the mechanisms involved in the glial response to axonal damage/degeneration, we developed an inducible model of peripheral sensory nerve degeneration in zebrafish. This model permits the conditional and selective ablation of peripheral sensory neurons and their axons. In our initial studies, we have found evidence that upon axon degeneration, peripheral glia are critical to the removal of axonal debris and recruitment of immune cells to sites of the involved nerves. The hypothesis that will be tested in this proposal is that axonal damage and degeneration induces glia to alter their gene expression, resulting in phagocytic behaviors and signaling to the immune system. In this application, we propose two aims: (1) identify genes involved in the response of peripheral glia to sensory neurodegeneration and (2) to validate the candidate genes identified in Aim 1. This will be achieved through transcriptome analysis of control and metronidazole- treated fish. Validation of candidate genes will be performed using qPCR, in situ hybridization and CRISPR/Cas9 mediated deletion analysis. Identification of involved genes will provide an important foundation for future investigations into the mechanisms by which peripheral glia react to death and degeneration of sensory circuits, and can be used as the starting points for directed studies in higher vertebrates, with the eventual goal of developing new directions in clinical efforts to treat this aspect of many debilitating sensory neuropathies.