Therapeutic potential and the critical site of action of non-addicting glibenclamide in neuropathic pain

背景：几乎一半的退伍军人经历慢性疼痛，这与 2500万美国平民遭受着严重的慢性疼痛。慢性疼痛是一种常见的 与军事和恐怖有关的伤害的后遗症。大多数战场上的创伤都涉及暴露在 四肢，导致周围神经受损引起的神经病理性疼痛的发生率很高。阿片类药物使用障碍 正在进行的“阿片类药物流行”在一定程度上是由合法使用用于神经性疾病的阿片类药物引起的。 疼痛。部署后，15%的退伍军人使用阿片类药物，而一般人口的这一比例为4%。 对于退伍军人来说，阿片类药物的使用与自杀有直接关系。靶向替代非阿片类药物 使用非成瘾药物控制疼痛的途径是神经病理性疼痛研究的主要目标。在外围设备之后 神经损伤(PNI)、细胞因子和趋化因子在中枢上调，包括在背角星形胶质细胞， 它们在神经病理性疼痛的发病机制中起到了机械作用。背部反应性星形胶质细胞 角蛋白表现出一种慢性激活的促炎分泌(CAPS)表型，其特征是 分泌多种因子，包括白细胞介素6(IL-6)、趋化因子C-C基序配体2(CCL2)和 趋化因子C-X-C基序配体1(CXCL1)，每一种都被证明与神经病变有关 疼痛行为。PNI后星形细胞帽的表型与炎症和神经元有关 通过神经元趋化因子受体过度激活，导致神经病理性疼痛。我们的试点数据表明 新发现，在神经病理性疼痛的小鼠坐骨神经袖套模型中，抑制磺脲受体1 (SUR1)，连续几周每天服用小剂量格列本脲，在治疗期间开始治疗 PNI后第21天的慢性期，导致以下方面的显著减少：(I)机械性超敏、热痛觉过敏 背角星形胶质细胞表达IL-6、CCL2和CXCL1。 描述：该项目具有临床相关目标，即确定治疗潜力、耐受性、 以及格列本脲治疗PNI所致神经病理性疼痛行为的关键作用部位。四个独立的 计划在雄性和雌性小鼠坐骨神经袖带模型上进行实验，并进行治疗 仅在慢性期，即PNI后3周。在这些实验中，我们将检查：(A)各种不同的能力 全身剂量和鞘内注射格列本脲可有效逆转神经病理性疼痛行为(机械性疼痛 痛觉过敏、热痛觉过敏、位置逃避/回避、焦虑和类似抑郁的行为)，以及相关 运动功能障碍；(B)全身性格列本脲逐渐消退神经炎症的能力。 背根神经节/背角，与观察到的痛觉异常逐渐消退相关；(C) 治疗停止后格列本脲治疗；和(D)作用部位的解剖和细胞。 格列本脲。将对小鼠进行长达11周的神经病理性疼痛行为和运动功能研究；DRG和 将研究背角组织的神经炎症，包括星形胶质细胞和小胶质细胞的激活，以及 SUR1-TRPM4、IL-6、CCL2和CXCL1的表达。这个项目是第一个研究神经病理效应的项目。 格列本脲对SUR1疼痛的抑制作用，安全、不成瘾，可重新用于治疗 治疗神经病理性疼痛，从而大大改善受影响退伍军人的功能。

BACKGROUND: Almost half of Veterans experience chronic pain, which is disproportionately greater than the 25 million Americans in the civilian population who suffer from significant chronic pain. Chronic pain is a common sequela of military- and terror-related injuries. The majority of battlefield wounds involve injuries to exposed limbs, resulting in high rates of neuropathic pain caused by damage to a peripheral nerve. Opioid use disorder and the ongoing “opioid epidemic” are driven in part by the legitimate use of opioids prescribed for neuropathic pain. Post-deployment, 15% of military Veterans use opioids, compared to 4% of the general population, and in Veterans, there is a direct correlation between the use of opioids and suicide. Targeting alternative non-opioid pathways for pain control using non-addicting drugs is a major goal of neuropathic pain research. After peripheral nerve injury (PNI), cytokines and chemokines are upregulated centrally, including in dorsal horn astrocytes, where they contribute mechanistically to the pathogenesis of neuropathic pain. Reactive astrocytes in the dorsal horn exhibit a chronically activated, pro-inflammatory secretory (CAPS) phenotype characterized by the secretion of numerous factors, including interleukin-6 (IL-6), chemokine C-C motif ligand 2 (CCL2) and chemokine C-X-C motif ligand 1 (CXCL1), each of which individually has been shown to contribute to neuropathic pain behaviors. The post-PNI astrocytic CAPS phenotype contributes to both inflammation and neuronal hyperactivation via neuronal chemokine receptors, leading to neuropathic pain. Our pilot data demonstrate the novel findings that, in the murine sciatic nerve cuff model of neuropathic pain, inhibiting sulfonylurea receptor 1 (SUR1) with low-dose glibenclamide administered daily over several weeks, with treatment beginning during the chronic phase at day21 after PNI, causes marked reductions in: (i) mechanical allodynia, thermal hyperalgesia and place escape/avoidance; (ii) dorsal horn astrocyte expression of IL-6, CCL2 and CXCL1. DESCRIPTION: This project has the clinically relevant aim of establishing the therapeutic potential, durability, and critical site of action of glibenclamide treatment in neuropathic pain behaviors induced by PNI. Four separate experiments are planned in males and females using the murine sciatic nerve cuff model, with treatments applied only during the chronic phase, 3 weeks after PNI. In these experiments, we will examine: (a) the ability of various doses of systemic and intrathecal glibenclamide to effectively reverse neuropathic pain behaviors (mechanical allodynia, thermal hyperalgesia, place escape/avoidance, anxiety and depression-like behaviors), and related motor dysfunction; (b) the ability of systemic glibenclamide to gradually extinguish neuroinflammation in the DRG/dorsal horn, for correlation with the observed gradual extinction of allodynia; (c) the durability of glibenclamide treatment after treatment cessation; and (d) the anatomical and cellular site of action of glibenclamide. Mice will be studied up to 11 weeks for neuropathic pain behaviors and motor function; DRG and dorsal horn tissues will be studied for neuroinflammation, including astrocyte and microglial activation, and expression of SUR1-TRPM4, IL-6, CCL2 and CXCL1. This project is the first to study the effects in neuropathic pain of SUR1 inhibition by glibenclamide, which is safe, non-addicting and could be repurposed for the treatment of neuropathic pain, thereby greatly improving the function of affected Veterans.