Validation of Neuropilin-1 receptor signaling in nociceptive processing

摘要 伤害性疼痛是一种对有害刺激的保护性反应，是在伤害性疼痛时生存所必需的。 代表由外周伤害性感受器神经元敏化引起的伤害性感觉改变 到引发疼痛反应的亚阈值输入。在研究SARS-CoV-2刺突蛋白的潜在作用时 在疼痛中，我们发现Neuropilin 1(Nrp1)是介导血管转导的关键受体 血管内皮细胞生长因子-A(VEGFA)信号在肿瘤痛模型中敏化感觉神经元。在……里面 神经损伤疼痛模型与血管生成因子--血管内皮生长因子-A的结合 Nrp1，并引起机械性痛觉过敏和热痛敏。Nrp1的药理拮抗作用 阻断VEGFA可诱导痛样行为。这项工作表明，Nrp1可能是一种新的治疗方法 具有逆转慢性疼痛的潜力的目标。从机制上讲，Nrp1位于胞浆蛋白的上游- N型电压门控钙离子双向转运调节蛋白CRMP2的表达 (Cav2.2)以及电压门控钠通道。我们假设激活的是 VEGFA/Nrp1/CRMP2/离子通道通路诱导背根神经节神经元敏化 因此，通过增加兴奋性突触对背部的输入而导致神经病理性疼痛状态 脊髓神经元。在这个提议中，我们检验了干扰VEGFA结合到 Nrp1通过CRMP2启动细胞内信号级联，导致钠离子减少 和钙通道功能活性，以减少伤害性感受器活动，最终减少疼痛样 行为。我们计划通过使用两个慢性疼痛模型来验证我们的假设，以回答以下问题： 1.Nrp1信号是否通过诱导伤害性感受器敏化和慢性超敏反应 CRMP2？ 2.Nrp1信号如何影响急、慢性疼痛？ 3.鞘内抑制NRP1的抗伤害性作用是否由靶向DRG介导 神经元、小胶质细胞，还是两者兼而有之？ 拟议研究的完成将允许：(1)确认慢性疼痛的新靶点；(2)使用两种慢性疼痛 探索疼痛模型的适用范围，以及(Iii)为开发 下一代基于机制的慢性止痛药。 总体而言，这些实验的完成将验证Nrp1在伤害感受处理中的作用，并将打开 Nrp1用于慢性疼痛治疗的未来治疗靶点的机会。

ABSTRACT Nociceptive pain is a protective response to harmful stimuli that is necessary to survival while nociplastic pain represents altered nociception arising from a sensitization of peripheral nociceptor neurons leading to subthreshold inputs eliciting a pain response. While studying a potential role for SARS-CoV-2 spike protein in pain, we identified Neuropilin 1 (NRP1) as a key receptor mediating the transduction of vascular endothelial growth factor-A (VEGFA) signaling to sensitize sensory neurons in models of nociplastic pain. In models of nerve injury pain, vascular endothelial growth factor-A (VEGFA) – an angiogenic factor – binds NRP1 and induces mechanical allodynia and thermal hyperalgesia. Pharmacological antagonism of NRP1 blocked VEGFA induced pain-like behaviors. This work demonstrated that NRP1 could be a novel therapeutic target with the potential to reverse chronic pain. Mechanistically, NRP1 sits upstream of a cytosolic protein – the collapsin response mediator protein 2 (CRMP2), a dual trafficking regulator of N-type voltage-gated calcium (CaV2.2) as well as voltage-gated sodium channels. We hypothesize that activation of the VEGFA/NRP1/CRMP2/ion channel pathway elicits sensitization of dorsal root ganglion neurons, consequently contributing to neuropathic pain states by enhancing excitatory synaptic input to dorsal spinal cord neurons. In this proposal, we test the hypothesis that interfering with VEGFA binding to NRP1 initiates an intracellular signaling cascade that, through CRMP2, leads to a decrease in sodium and calcium channel functional activity to decrease nociceptor activity culminating in reduced pain-like behaviors. We plan to test our hypothesis by using two chronic pain models to answer the following questions: 1. Does NRP1 signaling induce nociceptor sensitization and chronic hypersensitivity via CRMP2? 2. How does NRP1 signaling affect acute and chronic pain? 3. Are the anti-nociceptive effects of intrathecal NRP1inhibition mediated by targeting DRG neurons, microglia, or both? Completion of the proposed studies will allow: (i) validation of a novel target of chronic pain, (ii) use two chronic pain models to explore the breadth of applicability, and (iii) provide important information for development of a next generation of mechanism-based chronic pain medications. Overall, completion of these experiments will validate the role of NRP1 in nociceptive processing and will open opportunities for future therapeutic targeting of NRP1 for chronic pain treatment.