Peripheral mechanisms of central neuropathic pain in multiple sclerosis

多发性硬化症中枢神经病理性疼痛的外周机制

基本信息

批准号：
10495198
负责人：
Kayla Lee Nguyen
金额：
$ 1.44万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-15 至 2022-09-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10495198
关键词：
Ablation Action Potentials Address Affective Afferent Neurons Amyloid beta-Protein Animal Model Behavioral Brain C Fiber Calcium Caliber Capsaicin Career Choice Cells Data Development Diabetic Neuropathies Dorsal Electrophysiology (science)Experimental Autoimmune Encephalomyelitis Family member Fiber Fire - disasters Flagellin Frequencies Fura-2 Future Goals Halorhodopsins Hypersensitivity Image Implant Inflammatory Injections Injury Interneurons Intervention Isolectin Knockout Mice Knowledge Laboratories Learning Lesion Light Literature Maintenance Measurement Measures Mechanics Methods Modeling Multiple Sclerosis Mus Neonatal Neurons Nociceptors Pain Pain Clinics Pain Research Pain management Pathologic Patients Peripheral Pharmaceutical Preparations Phosphotransferases Population Posterior Horn Cells Process Reflex action Reporting Skin Slice Spinal Spinal Cord Spinal Ganglia Spinal cord injury Stimulus Substantia Gelatinosa Tamoxifen Techniques Testing Therapeutic Transgenic Organisms Traumatic Nerve Injury Tropomyosin Woman chronic pain conditional knockout inflammatory pain mechanical allodynia member multiple sclerosis patient optogenetics pain relief painful neuropathy receptor response somatosensory subcutaneous therapeutically effective

项目摘要

Nguyen, Kayla PROJECT SUMMARY/ABSTRACT Neuropathic Pain (NP) afflicts over 50% of patients with multiple sclerosis (MS), yet current treatments for pain relief are inadequate, in part because mechanisms that drive MS pain are poorly understood. In a widely-used animal model of MS, experimental autoimmune encephalomyelitis (EAE), recent electrophysiological recordings of primary afferent neurons (PANs) in the dorsal root ganglion (DRG) revealed: 1) hyperexcitability of medium- to-large diameter neurons and 2) an increase in afterhyperpolarization of small-diameter fibers. These data provide the premise for my long-term goal to investigate the sensitization mechanisms at PANs that drive NP in the EAE model. With behavioral, transgenic, and ablation techniques, I propose to assess the contribution of A and C-fibers to MS pain upon testing the overall hypothesis that EAE produces a persistent hyperexcitability of A and/or C-nociceptors (Aim 1,2) that is associated with increased activity of dorsal horn (DH) neurons (Aim 3) that then drives NP. Aim 1 uses neuronal ablation strategies to identify which subpopulations of primary afferent neurons contribute to NP in EAE. I will use simple conventional neuronal ablation strategies (neonatal capsaicin, intrathecal capsaicin, intrathecal IB4-saporin, intraplantar flagellin/QX-314), followed by a more labor-intensive but powerful conditional knockout approach to eliminate the activity of increasingly precise PAN subsets. I predict that the proposed interventions will reduce key indicators of EAE-induced pain: mechanical and cold hypersensitivity (reflexive pain) and conditioned place aversion (affective pain). Aim 2 uses chemogenetics and optogenetics to test the hypothesis that either Mrgprd- or TrkC-expressing PANs are necessary for NP in EAE. I predict that CreER selective manipulations to inhibit either the MrgprD+ subset of IB4 neurons or the TrkC+ subset of myelinated neurons (decision driven by the results of Aim 1a-b) will reduce EAE mechanical and cold hypersensitivity. Aim 3 will test the hypothesis that EAE sensitizes the somatosensory stimulus-induced activation of spinal interneurons and projection neurons. Our laboratory reported that EAE increases the activity of dorsal horn neurons as measured by the expression of pERK. I propose to extend these studies with a more powerful measure of neuronal activity using spinal cord slice Fura-2 calcium imaging, and by assessing the activity not only of interneurons, but also of projection neurons. The Pittsburgh Center for Pain Research will provide guidance, support, and learning opportunities that will promote the development of my scientific and investigative career aspirations.

阮凯拉项目概要/摘要超过 50% 的多发性硬化症 (MS) 患者患有神经性疼痛 (NP)，但目前的疼痛治疗方法缓解措施并不充分，部分原因是人们对多发性硬化症疼痛的机制知之甚少。在广泛使用的 MS 动物模型、实验性自身免疫性脑脊髓炎 (EAE)、近期电生理记录背根神经节 (DRG) 中的初级传入神经元 (PAN) 的功能揭示：1) 中- 2）小直径神经元后超极化的增加。这些数据为我的长期目标提供前提，即研究驱动 NP 的 PAN 敏化机制 EAE模型。通过行为、转基因和消融技术，我建议评估 A 的贡献在测试 EAE 产生持续性过度兴奋的总体假设后，将 C 纤维与 MS 疼痛联系起来 A 和/或 C 伤害感受器（目标 1,2）与背角 (DH) 神经元活动增加相关（目标 3）然后驱动 NP。目标 1 使用神经元消融策略来识别初级传入神经的哪些亚群神经元有助于 EAE 中的 NP。我将使用简单的常规神经元消融策略（新生儿辣椒素，鞘内注射辣椒素、鞘内注射 IB4-皂草素、足底内鞭毛蛋白/QX-314），然后是劳动密集型的但强大的条件敲除方法可以消除日益精确的 PAN 子集的活性。我预测拟议的干预措施将减少 EAE 引起的疼痛的关键指标：机械性疼痛和冷痛过敏（反射性疼痛）和条件性位置厌恶（情感性疼痛）。目标 2 使用化学遗传学和光遗传学来检验以下假设：表达 Mrgprd 或 TrkC 的 PAN 对于 EAE 中的 NP 是必需的。我预测 CreER 会进行选择性操作来抑制 IB4 神经元的 MrgprD+ 子集或 TrkC+ 有髓神经元子集（由目标 1a-b 结果驱动的决策）将减少 EAE 机械和寒冷超敏反应。目标 3 将检验 EAE 使体感刺激诱发的假设变得敏感脊髓中间神经元和投射神经元的激活。我们的实验室报告 EAE 增加了活性通过 pERK 的表达测量背角神经元的数量。我建议以更多的方式扩展这些研究使用脊髓切片 Fura-2 钙成像来强有力地测量神经元活动，并通过评估不仅是中间神经元的活动，而且是投射神经元的活动。匹兹堡疼痛研究中心将提供指导、支持和学习机会，以促进我的科学和技术的发展调查职业抱负。