The Role of the Neuronal Membrane Proteasome in the Peripheral Nervous System and Pain Sensation

项目摘要 虽然蛋白酶体通常被称为蛋白质降解机器，但现在认为它具有 神经系统中的额外信号功能。一个鲜为人知但在治疗上很重要的作用 因为蛋白酶体在外周神经系统（PNS）中参与疼痛调节。然而， 蛋白酶体活性对痛觉的影响是复杂的，并且有些自相矛盾：蛋白酶体抑制已经被认为是一种有效的方法。 发现可以减轻疼痛或引起疼痛敏感化和周围神经病变，具体取决于持续时间 抑制、抑制剂类型和抑制剂剂量。最近的一项发现可能会让我们深入了解这种监管 其机制是我们实验室检测到一种与血浆结合的神经元特异性蛋白酶体 一种快速调节活性依赖性神经元钙离子的膜（NMP：神经元膜蛋白酶体） 通过细胞外信号肽的释放进行信号传导。我们实验室的初步数据显示， 表明NMP抑制减少背根神经节伤害感受器活性和机械性疼痛 敏感性，表明这种新的神经元通讯途径可能是关键的蛋白酶体/疼痛 信号然而，关于NMP的许多基本问题仍然存在，包括它与细胞溶质的区别。 蛋白酶体以及不同神经元亚群中的NMP表达如何影响痛觉。的 该建议的中心假设是PNS NMP在疼痛信号传导中起重要作用， PNS感觉神经元中NMP表达的特征，包括亚型特异性活动模式， 膜定位模式，通过旁分泌的差异直接影响其对疼痛敏感性的调节 发信号。为了解决这一假设，我们提出了一系列的生化，分子，生理， 针对两个具体目标的行为测定：目标1。确定NMP的分布和结构 在PNS神经元膜中;和Aim 2.研究PNS NMP在不同神经元亚型中的作用 与痛觉有关。这些目标的实现将阐明PNS的基本性质 NMP和提供洞察其在疼痛感觉的调节作用，确定可能的治疗途径， 疼痛调节，并为未来研究PNS NMP在健康中的作用奠定基础 和疾病

PROJECT SUMMARY While the proteasome is typically known as protein degradation machinery, it is now recognized to have additional signaling functions in the nervous system. One poorly understood but therapeutically important role for the proteasome is in pain regulation in the peripheral nervous system (PNS). However, the relationship of proteasome activity to pain sensation is complex and somewhat paradoxical: proteasome inhibition has been found to either reduce pain or to cause pain sensitization and peripheral neuropathies depending on length of inhibition, type of inhibitor, and inhibitor dose. A recent discovery that may grant insight into this regulatory mechanism is our laboratory’s detection of a specialized, neuron-specific proteasome bound to the plasma membrane (NMP: neuronal membrane proteasome) that rapidly modulates activity-dependent neuronal calcium signaling through the release of extracellular signaling peptides. Preliminary data from our laboratory has demonstrated that NMP inhibition reduces dorsal root ganglion nociceptor activity and mechanical pain sensitivity, indicating that this novel neuronal communication pathway may be critical in proteasome/pain signaling. However, many fundamental questions about the NMP remain, including how it differs from cytosolic proteasomes and how variable NMP expression across neuronal sub-populations affects pain sensation. The central hypothesis of this proposal is that the PNS NMP plays an important role in pain signaling and that characteristics of NMP expression in PNS sensory neurons, including subtype-specific activity patterns and membrane localization patterns, directly affect its modulation of pain sensitization via differences in paracrine signaling. To address this hypothesis, we propose a series of biochemical, molecular, physiological, and behavioral assays addressing two specific aims: Aim 1. To determine the distribution and structure of the NMP in PNS neuronal membranes; and Aim 2. To investigate the role of the PNS NMP in diverse neuronal subtypes relevant to pain sensation. The completion of these aims will elucidate fundamental properties about the PNS NMP and provide insight into its regulatory role in pain sensation, identifying possible therapeutic avenues for pain modulation and laying the foundation for future investigations examining the role of the PNS NMP in health and disease.