MECHANISMS OF CSD-EVOKED PERSISTENT ACTIVATION OF MENINGEAL NOCICEPTORS

CSD 诱发脑膜伤害感受器持续激活的机制

• 批准号: 9767291
• 负责人: DAN LEVY
• 金额: $ 41.05万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-15 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9767291
• 关键词: Acute; Affect; Afferent Neurons; Animals; Astrocytes; Auras; Behavior; Behavioral; Biological Process; Biosensor; Calcium; Cephalic; Chronic; Classic Migraine; Common Migraine; Conflict (Psychology); Data; Dichloromethylene Diphosphonate; Disease; Electrophysiology (science); Event; Exhibits; Fluoroacetates; Genetic; Grant; Headache; Hour; Image; Lead; Light; Link; Liposomes; Locomotion; Measures; Mechanics; Mediating; Meningeal; Meninges; Microelectrodes; Migraine; Molecular; Monitor; Mus; Naproxen; Nerve Endings; Neuropharmacology; Nociception; Nociceptors; Pain; Peripheral; Pharmacology; Phase; Play; Purinoceptor; Receptor Signaling; Rodent Model; Role; Sensory; Sex Differences; Signal Transduction; Spreading Cortical Depression; Stretching; Structure; Testing; Transgenic Mice; Trigeminal System; afferent nerve; awake; combat; disability; experimental study; imaging approach; in vivo; inhibitor/antagonist; innovation; insight; macrophage; new therapeutic target; novel; optogenetics; pain behavior; receptor; response; sensory system; theories; two-photon

Migraine is the second leading cause of disability worldwide; however, it remains unclear how the headache phase is initiated during a migraine attack. In migraine with aura, a condition that affects about 30% of people with migraine, the leading theory proposes that (a) cortical spreading depression (CSD) is the pathophysiological event that underlies the aura phase, and b) CSD somehow leads to the activation of the meningeal sensory system, resulting in the onset of the headache. Our recent studies, including during the prior grant period, provided a long-missing critical piece of support for the theory by finally showing that CSD does in fact activate meningeal sensory afferents, and can produce a prolonged period of both activation and mechanical sensitization. However, a long-standing problem with the CSD theory has been the paucity of evidence that CSD leads to pain behaviors, as would be expected for an event that supposedly is a potent trigger for headache. Furthermore, efforts to establish a link between CSD, the ensuing meningeal afferent responses, and headache pain have been limited by the challenges of studying the activity of meningeal sensory neurons in awake behaving animals. We have overcome this major obstacle by developing a two- photon calcium imaging approach to monitor the activity of meningeal afferent nerve endings in the awake behaving mouse, during voluntary locomotion via a chronic cranial window. In Aim 1, we propose to pursue this novel imaging approach to expand upon preliminary data suggesting that as a result of CSD-induced mechanical sensitization, meningeal stretching during voluntary locomotion results in enhanced activation of meningeal afferents, and consequent reduction of locomotion. Aims 2 and 3 are to explore cellular and molecular mechanisms that contribute to meningeal nociception following CSD. We will build upon preliminary results and use electrophysiology in anesthetized animals, calcium imaging in awake mice and an optogenetic approach to test the hypothesis that cortical astrocytes play a causal role in mediating the enhanced meningeal afferent responses and related decrease in voluntary locomotion following CSD. We will then employ biosensors, electrophysiology, afferent calcium imaging, pharmacological inhibitors and transgenic mice to test the hypothesis that astrocyte-dependent cortical ATP efflux contributes to CSD-evoked meningeal nociception via purinergic P2X7 signaling in meningeal macrophages. These innovative experiments, in addition of establishing a novel powerful platform for studying the responses of meningeal afferents and associated behavioral consequences related to migraine headache, could also shed light on the roles of cortical astrocytes and meningeal purinergic signaling, as well as sex differences in the mechanisms responsible for migraine pain - a key step towards mitigating the painful effects of CSD in migraine with aura.

偏头痛是全球第二大致残原因；然而，目前尚不清楚头痛是如何发生的 阶段是在偏头痛发作期间启动的。有先兆偏头痛，这种疾病影响约 30% 的人 对于偏头痛，主要理论认为 (a) 皮质扩散性抑制 (CSD) 是 b) CSD 以某种方式导致先兆阶段的病理生理事件的激活 脑膜感觉系统，导致头痛发作。我们最近的研究，包括在 之前的资助期，通过最终表明 CSD 为该理论提供了长期缺失的关键支持 事实上，它确实激活了脑膜感觉传入，并且可以产生长时间的激活和 机械敏化。然而，CSD 理论的一个长期存在的问题是缺乏 有证据表明 CSD 会导致疼痛行为，正如对被认为是有效的事件所预期的那样 引发头痛。此外，努力在 CSD、随后的脑膜传入神经之间建立联系 研究脑膜活动的挑战限制了反应和头痛 清醒行为动物的感觉神经元。我们通过开发两种方法克服了这一主要障碍 光子钙成像方法监测清醒状态下脑膜传入神经末梢的活动 行为小鼠，通过慢性颅窗自愿运动。在目标 1 中，我们建议追求这一目标 新颖的成像方法扩展了初步数据，表明由于 CSD 引起的 机械敏化，随意运动期间脑膜拉伸导致增强的激活 脑膜传入，以及随之而来的运动减少。目标 2 和 3 是探索细胞和 CSD 后脑膜伤害感受的分子机制。我们将在初步基础上 结果并使用麻醉动物的电生理学、清醒小鼠的钙成像和光遗传学 方法来检验皮质星形胶质细胞在介导增强的脑膜中发挥因果作用的假设 CSD 后传入反应和相关的自主运动减少。然后我们将雇用 生物传感器、电生理学、传入钙成像、药理学抑制剂和转基因小鼠进行测试 星形胶质细胞依赖性皮质 ATP 流出有助于 CSD 诱发的脑膜伤害感受的假设 通过脑膜巨噬细胞中的嘌呤能 P2X7 信号传导。这些创新实验，除了 建立一个新颖的强大平台来研究脑膜传入和相关的反应 与偏头痛相关的行为后果也可以揭示皮质星形胶质细胞的作用 和脑膜嘌呤能信号传导，以及导致偏头痛的机制中的性别差异 疼痛 - 减轻先兆偏头痛 CSD 疼痛影响的关键一步。