Role of Pannexin-1 in Chemotherapy-Induced Neuropathic Pain

项目总结/摘要 神经性疼痛是用细胞毒性化学治疗剂（例如化疗剂）治疗癌症的失能后果。 如紫杉醇。慢性疼痛的经济成本，包括神经性疼痛作为一个大的组成部分，已经被 估计仅在美国就超过5000亿美元。现有的治疗方法在很大程度上是无效的， 疼痛是减少化疗剂量的最常见原因之一。神经性疼痛可能是短暂的 长期（急性神经性疼痛）或在多次化疗后持续（慢性神经性疼痛） 疼痛）。尽管与化疗诱导的周围神经病变（CIPN）相关的疼痛机制 其他形式的慢性神经性疼痛通常与炎症过程有关， 嘌呤能信号我们的研究小组以前发现，释放ATP和ATP的Pannexin 1（Panx 1）通道， 其他潜在的促炎代谢物，是神经性疾病的发展和维持所必需的。 直接神经损伤后的疼痛。因此，我假设Panx 1也可能导致CIPN相关疼痛。 我从基因敲除小鼠获得的令人兴奋的初步数据揭示了Panx 1的独特作用，特别是在过渡中。 从急性疼痛到慢性疼痛。具体地说，Panx 1缺失小鼠发生急性机械超敏反应， 紫杉醇的初始回合，但不像野生型小鼠，神经性疼痛没有维持和解决 在第二次紫杉醇注射后在这个建议中，我研究了细胞和机械的基础，这种作用， 用紫杉醇处理的小鼠进行行为测定，沿着电生理和免疫学检查， 背根神经节（DRG）中感觉神经元和免疫细胞的表征。在目标1中，我使用基因 和药理学工具，包括全球和细胞特异性Panx 1敲除小鼠，以确定 造血细胞中Panx 1对慢性神经病理性疼痛的作用驱动目标2的假设是， Panx 1是紫杉醇反复发作后DRG持续炎症所必需的。我用贴片 钳夹电生理学、流式细胞术和免疫组织化学来确定神经元兴奋性， 在神经病理性疼痛的急性和慢性阶段的DRG的炎症状态。总的来说，这项建议将 提供了关于Panx 1参与慢性化疗诱导的神经性疼痛的新信息， 将Panx 1视为治疗这种挽救生命的衰弱副作用的新靶点的理由 细胞毒性化疗。

PROJECT SUMMARY/ABSTRACT Neuropathic pain is an incapacitating consequence of cancer treatment with cytotoxic chemotherapeutics, such as paclitaxel. The economic cost of chronic pain, including neuropathic pain as a large component, has been estimated to be over $500 billion in the US alone. Existing treatments are largely ineffective, and neuropathic pain is one of the most common reasons for reducing chemotherapy dosing. Neuropathic pain may be short term (acute neuropathic pain) or it may persist after multiple doses of chemotherapy (chronic neuropathic pain). Although mechanisms for pain associated with chemotherapeutic-induced peripheral neuropathy (CIPN) are not known, other forms of chronic neuropathic pain are often associated with an inflammatory process and purinergic signaling. Our group previously found that Pannexin 1 (Panx1) channels, which release ATP and other potentially pro-inflammatory metabolites, are required for development and maintenance of neuropathic pain after direct nerve injury. Thus, I hypothesize that Panx1 may also contribute to CIPN-associated pain. My exciting preliminary data from knockout mice reveal a unique role for Panx1 specifically in the transition from acute to chronic pain. Specifically, Panx1-deleted mice developed acute mechanical hypersensitivity after an initial bout of paclitaxel, but unlike wild type mice, the neuropathic pain was not maintained and resolved after a second bout of paclitaxel. In this proposal, I examine the cellular and mechanistic basis for this role of Panx1 using behavioral assays with paclitaxel-treated mice, along with electrophysiological and immunological characterization of sensory neurons and immune cells in dorsal root ganglion (DRG). In Aim 1, I use genetic and pharmacological tools, including global and cell-specific Panx1 knockout mice, to determine the contribution of Panx1 in hematopoietic cells to chronic neuropathic pain. The hypothesis driving Aim 2 is that Panx1 is necessary for the persistent inflammation of DRG after repeated bouts of paclitaxel. I use patch clamp electrophysiology, flow-cytometry, and immunohistochemistry to determine neuron excitability and inflammatory states of DRG during acute and chronic phase of neuropathic pain. Collectively, this proposal will provide new information regarding Panx1 involvement in chronic chemotherapy-induced neuropathic pain, and a rationale for considering Panx1 as a novel target for treating this debilitating side effect of life-saving cytotoxic chemotherapies.