Molecular Determinants of Synaptic Plasticity in Chronic Pain

项目摘要 我们研究计划的总体目标是阐明支配突触的潜在分子原理 与慢性疼痛相关的可塑性。慢性神经病理性疼痛是一个重要而又未被解决的临床问题。 谷氨酸α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic酸受体(AMPAR)介导绝大多数 哺乳动物中枢神经系统中的快速兴奋性突触传递。AMPAR是四聚阳离子 通道由GluA1到GluA4四个亚基的组合组装而成。GluA2特别是 对AMPAR的生物物理性质很重要，因为含有GluA2的AMPAR对钙离子是不渗透的。 相反，缺乏GluA2的AMPAR显示出内向整流电流，并具有高的钙通透性 因此被称为钙渗透性AMPAR(CP-AMPAR)。脊髓突触CP-AMPAR的分布 在神经病理性疼痛中，背角神经元明显增多。然而，潜在的分子机制 AMPAR亚单位组成在神经病理性疼痛中的变化仍鲜为人知。我们的主要目标是 提案是确定负责监管组装和贩运的关键分子机制 神经病理性疼痛中的CP-AMPARα-2δ-1，通常被认为是钙通道亚单位，在脊髓中上调 神经病理性疼痛中的背角。我们的初步研究表明，α-2δ-1在体外与AMPAR亚基相互作用 在体内，α-2δ-1的表达增加促进了CP-AMPAR在脊髓的突触整合 后角。在这个提案中，我们将检验我们的总体假设，即α2δ-1增强突触CP-AMPAR 脊髓背角神经元通过与AMPAR亚单位的物理相互作用在神经病理性疼痛中的发生率 优先调节它们的亚单位组成和突触运输。我们将使用多学科方法 α-2、δ-1-AMPAR偶联及其在神经病理性疼痛分子、细胞和行为中的作用 级别。在我们的项目完成时，我们将获得重要的机械性洞察力，以了解 α-2、δ-1在神经损伤和糖尿病神经病变引起的神经病理性疼痛和突触可塑性中的作用。这是一项新的 信息将重新定义α2δ-1的生理功能以及α2δ-1结合的CP-AMPAR在 加巴喷丁的治疗效果。因此，拟议研究的结果将具有持续性 通过促进我们对神经病理性疼痛的突触机制的理解，产生积极的影响，导致 慢性神经病理性疼痛新疗法的开发。

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.