Molecular Determinants of Synaptic Plasticity in Chronic Pain

项目概要 我们研究计划的总体目标是阐明控制突触的基本分子原理 与慢性疼痛相关的可塑性。慢性神经性疼痛是一个重要且尚未解决的临床问题。 谷氨酸 α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体 (AMPAR) 介导绝大多数 哺乳动物中枢神经系统中快速兴奋性突触传递的研究。 AMPAR 是四聚体阳离子 通道由四个亚基（GluA1 至 GluA4）的组合组件组成。 GluA2 特别是 对于 AMPAR 的生物物理特性很重要，因为含 GluA2 的 AMPAR 对 Ca2 是不可渗透的。 相比之下，缺乏 GluA2 的 AMPAR 显示内向整流电流，并且具有高 Ca2 渗透性，并且 因此被称为 Ca2 渗透性 AMPAR（CP-AMPAR）。脊髓突触 CP-AMPAR 的患病率 神经性疼痛时背角神经元明显增加。然而，其背后的分子机制 AMPAR 亚基组成在神经性疼痛中的转变仍鲜为人知。我们的主要目标 提议是确定负责调节组装和贩运的关键分子机制 CP-AMPAR 治疗神经性疼痛。 α2δ-1，通常被认为是 Ca2 通道亚基，在脊髓中上调 神经性疼痛的背角。我们的初步研究表明α2δ-1在体外与AMPAR亚基相互作用 在体内，α2δ-1 表达的增加促进了 CP-AMPAR 在脊髓中的突触掺入 背角。在这个提案中，我们将测试我们的总体假设，即 α2δ-1 增强突触 CP-AMPAR 通过与 AMPAR 亚基的物理相互作用，脊髓背角神经元在神经性疼痛中的患病率 优先调节其亚基组成和突触运输。我们将采用多学科方法 研究 α2δ-1-AMPAR 耦合及其在分子、细胞和行为神经病理性疼痛中的独特作用 水平。在我们的项目完成时，我们将对定义不明确的角色获得重要的机制洞察 α2δ-1 在神经损伤和糖尿病神经病变引起的突触可塑性和神经性疼痛中的作用。这个新的 这些信息将重新定义α2δ-1的生理功能以及α2δ-1结合的CP-AMPAR在 加巴喷丁类药物的治疗作用。因此，拟议研究的结果将具有持续性 通过增进我们对神经性疼痛突触机制的理解来产生积极影响，从而导致 开发治疗慢性神经性疼痛的新疗法。

Project Summary The overall goal of our research program is to elucidate the underlying molecular principles that govern synaptic plasticity associated with chronic pain. Chronic neuropathic pain is a significant and unmet clinical problem. Glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) mediate the vast majority of fast excitatory synaptic transmission in the mammalian central nervous system. AMPARs are tetrameric cation channels composed of a combinational assembly of four subunits, GluA1 through GluA4. GluA2 is particularly important for the biophysical properties of AMPARs because GluA2-containing AMPARs are impermeable to Ca2+. In contrast, GluA2-lacking AMPARs show inward-rectifying currents and have a high Ca2+ permeability and are thus referred to as Ca2+-permeable AMPARs (CP-AMPARs). The prevalence of synaptic CP-AMPARs of spinal dorsal horn neurons is markedly increased in neuropathic pain. However, the molecular mechanisms underlying the switch of AMPAR subunit composition in neuropathic pain remain little known. The major objective of our proposal is to determine the key molecular mechanism responsible for regulating the assembly and trafficking of CP-AMPARs in neuropathic pain. α2δ-1, often considered a Ca2+ channel subunit, is upregulated in the spinal dorsal horn in neuropathic pain. Our preliminary studies showed that α2δ-1 interacted with AMPAR subunits in vitro and in vivo and that increased α2δ-1 expression promoted synaptic incorporation of CP-AMPARs in the spinal dorsal horn. In this proposal, we will test our overall hypothesis that α2δ-1 potentiates the synaptic CP-AMPAR prevalence in spinal dorsal horn neurons in neuropathic pain through physical interaction with AMPAR subunits to preferentially regulate their subunit composition and synaptic trafficking. We will use a multidisciplinary approach to study α2δ-1–AMPAR coupling and its distinct role in neuropathic pain at molecular, cellular, and behavioral levels. At the completion of our project, we will gain significant mechanistic insight into the poorly defined role of α2δ-1 in synaptic plasticity and neuropathic pain caused by nerve injury and diabetic neuropathy. This new information will redefine the physiological function α2δ-1 and the role of α2δ-1–bound CP-AMPARs in the therapeutic effects of gabapentinoids. Therefore, the findings from the proposed studies will have a sustained positive impact by advancing our understanding of the synaptic mechanism of neuropathic pain, leading to the development of new therapies for chronic neuropathic pain.