Molecular Determinants of Synaptic Plasticity in Chronic Pain

慢性疼痛中突触可塑性的分子决定因素 我们项目的长期目标是确定控制突触的分子和信号机制， 在慢性疼痛条件下的可塑性。神经病理性疼痛仍然是一个主要的治疗挑战， 脊髓水平的可塑性对于慢性神经性疼痛的发展是根本重要的。不，不 甲基-D-天冬氨酸受体（NMDAR）在初级感觉神经元及其中枢终末中表达 在脊髓背角然而，它们在正常情况下功能不活跃， 在神经损伤和化疗后激活以增强对脊髓背角神经元的突触能输入- 诱发性神经病神经元突触活动和NMDARs转运调控的分子机制 脊髓背角仍然知之甚少。容量调节阴离子通道，由多个 不同的富含亮氨酸重复序列的蛋白8（LRRC8）家族成员，对细胞的调节至关重要。 音量.在我们的初步研究中，我们发现LRRC8A在背根神经节（DRG）神经元中高度表达。 此外，创伤性神经损伤选择性下调DRG中的LRRC8A，但不下调LRRC8B-LRRC8D。 此外，DRG神经元中的LRRC8A下调或条件性敲除诱导NMDAR依赖性神经元凋亡。 疼痛过敏重要的是，我们发现LRRC8A与NMDAR发生物理相互作用， 突触运输和NMDAR活性。在这次续约申请中，我们将具体确定 LRRC8A在两种神经病性脊髓损伤的脊髓水平上对伤害感受和突触NMDARs的调节 疼痛模型在我们有趣的初步数据的基础上，我们建议测试整体假设， LRRC8A蛋白直接与NMDAR相互作用，并且通常抑制NMDAR的突触运输。 脊髓水平;神经损伤或化疗减少LRRC8A表达并增加突触 NMDAR的表达和活性，导致脊髓背角神经元的突触能输入增加， 慢性疼痛我们将采用几种创新和互补的方法，包括生物化学和生物化学。 细胞分析，转基因小鼠和突触记录，以研究LRRC8A如何控制NMDAR， 分子、细胞和行为水平的伤害感受。我们的项目将产生基本的新信息 关于神经病理性疼痛中NMDAR介导的突触可塑性的分子基础。我们项目的发现 有望推进我们对伤害性调节的分子机制的认识，并指导 开发治疗慢性神经性疼痛的新策略。

Molecular Determinants of Synaptic Plasticity in Chronic Pain The long-term goal of our project is to identify the molecular and signaling mechanisms that govern synaptic plasticity under chronic pain conditions. Neuropathic pain remains a major therapeutic challenge, and neuronal plasticity at the spinal cord level is fundamentally important to the development of chronic neuropathic pain. N- methyl-D-aspartate receptors (NMDARs) are expressed in primary sensory neurons and their central terminals in the spinal dorsal horn. However, they are functionally inactive under normal conditions and become tonically activated to potentiate glutamatergic input to spinal dorsal horn neurons after nerve injury and chemotherapy- induced neuropathy. The molecular mechanisms regulating the synaptic activity and trafficking of NMDARs in the spinal dorsal horn remain poorly understood. Volume-regulated anion channels, which are formed by multiple different leucine-rich repeat-containing protein 8 (LRRC8) family members, are crucial to the regulation of cell volume. In our pilot studies, we found that LRRC8A was highly expressed in dorsal root ganglion (DRG) neurons. Also, traumatic nerve injury selectively downregulated LRRC8A, but not LRRC8B-LRRC8D, in the DRG. Furthermore, LRRC8A downregulation or conditional knockout in DRG neurons induces NMDAR-dependent pain hypersensitivity. Importantly, we discovered that LRRC8A physically interacted with NMDARs to control synaptic trafficking and activity of NMDARs. In this renewal application, we will specifically determine the roles of LRRC8A in the regulation of nociception and synaptic NMDARs at the spinal cord level in two neuropathic pain models. On the basis of our intriguing preliminary data, we propose to test the overall hypothesis that LRRC8A protein directly interacts with NMDARs and normally restrains the synaptic trafficking of NMDARs at the spinal cord level; nerve injury or chemotherapy diminishes LRRC8A expression and augments the synaptic expression and activity of NMDARs, leading to increased glutamatergic input to spinal dorsal horn neurons and chronic pain. We will apply several innovative and complementary approaches, including biochemical and cellular analyses, transgenic mice, and synaptic recordings to study how LRRC8A controls NMDARs and nociception at molecular, cellular, and behavioral levels. Our project will generate fundamental new information about the molecular basis of NMDAR-mediated synaptic plasticity in neuropathic pain. Findings from our project are expected to advance our knowledge of molecular mechanisms of nociceptive regulation and to guide the development of new strategies for treating chronic neuropathic pain.