Axonal Transport and Local Translation in Neuropathic Pain

描述（由申请人提供）： 局部蛋白质合成为神经元的远端突起提供了一种快速自主地对其环境做出反应的手段。虽然最好的特点是在树突隔室，在过去5年的工作已经证明，轴突能够局部产生新的蛋白质。在树突中，活性依赖性的局部蛋白质合成在突触可塑性中起作用。也有证据表明轴突中的活性依赖性蛋白质合成。鉴于轴突中合成的蛋白质的复杂群体，很可能轴突合成的蛋白质也在成熟轴突的功能中发挥作用。这一提议的中心假设是，感觉轴突中局部蛋白质合成的变化改变了神经元传播伤害性刺激的能力。这个建议的目的是了解轴突运输和局部蛋白质合成如何导致神经病理性疼痛状态的受损神经元表现出的过度兴奋。我们将使用体外和体内方法来确定离子通道和神经肽mRNA的运输和轴突下定位是否在神经性疼痛中改变，以及局部合成的离子通道是否功能性地插入轴质膜中，以及这种翻译和运输是否被神经性疼痛相关刺激改变。我们将利用嵌合mRNA报告构建体来解决这些转录本的轴突定位，无论是在培养的初级感觉神经元和转基因小鼠。局部合成的离子通道蛋白的GFP标记的融合蛋白将用于确定轴突合成的离子通道的功能相关性，最终目标是了解这些蛋白的轴突运输和局部合成如何有助于神经性疼痛。神经病理性疼痛是指周围神经损伤、感染或炎症后产生的慢性疼痛，与正常疼痛形成鲜明对比，两者都是引起神经病理性疼痛的分子机制，也是神经病理性疼痛对常规疼痛治疗的反应。目前神经创伤的动物模型提供了一些见解，神经元的变化，发生在周围神经损伤-揭示了显着程度的可塑性，在感觉神经元和脊髓。了解轴突运输和局部蛋白质合成如何有助于这些受损感觉神经元的过度兴奋性增加，可能会指向治疗病理性疼痛状态的替代方法。

DESCRIPTION (provided by applicant): Localized protein synthesis provides a means for the distal processes of the neuron to rapidly and autonomously respond to its environment. Although best characterized in the dendritic compartment, work over the past 5 years has proven that axons are capable of locally generating new proteins. In dendrites, activity-dependent local protein synthesis plays a role in synaptic plasticity. There is also evidence for activity-dependent protein synthesis in axons. Given the complex population of proteins synthesized in axons, it is likely that axonally synthesized proteins also play a role in the function of mature axons. The central hypothesis of this proposal is that changes in local protein synthesis in sensory axons alter the neuron's capacity for propagating noxious stimuli. The objective of this proposal is to understand how axonal transport and local protein synthesis contribute to hyperexcitability exhibited by damaged neurons leading to neuropathic pain states. We will use in vitro and in vivo methods to determine if the transport and sub-axonal localization of ion channel and neurotpeptide mRNAs are altered in neuropathic pain, and whether locally synthesized ion channels are functionally inserted into axoplasmic membranes and if this translation and trafficking are altered by neuropathic pain-associated stimuli. We will utilized chimeric mRNA reporter constructs to address axonal localization of these transcripts, both in cultured primary sensory neurons and in transgenic mice. GFP-tagged fusion proteins of locally synthesized ion channel proteins will be used to determine the functional relevance of axonally synthesized ion channels, with the ultimate goal of understanding how axonal trafficking and local synthesis of these proteins contributes to neuropathic pain. Neuropathic pain, the chronic pain experienced following injury, infection, or inflammation of peripheral nerves, sharply contrasts with normal pain, both is the molecular mechanisms which cause it and in their responses to conventional pain treatments. Current animal models of nerve trauma have provided some insights into the neuronal changes that occur in response to peripheral nerve damage - revealing a remarkable degree of plasticity in both the sensory neurons and spinal cord. Understanding how axonal transport and local protein synthesis contribute to increased hyperexcitability of these damaged sensory neurons may point to alternative methods of treating pathological pain states.