Ionic Mechanisms Underlying Dorsal Root Ganglion Excitability

背根神经节兴奋性的离子机制

基本信息

批准号：
8438806
负责人：
Arindam Bhattacharjee
金额：
$ 31.17万
依托单位：
STATE UNIVERSITY OF NEW YORK AT BUFFALO
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-01 至 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8438806
关键词：
Affect Afferent Neurons Analgesics Attenuated Behavior Behavioral Assay Binding Biochemical Cells Complex Consensus Diabetes Mellitus Diabetic Neuropathies Diabetic mouse Esthesia Exhibits Family Functional disorder Future Gene Expression Genes Glucose Goals Hyperalgesia Immunohistochemistry Ions Kinetics Knockout Mice Label Lead Link Marshal Metabolic Mitogen Activated Protein Kinase 1 Modeling Molecular Mus Nervous system structure Neurons Neuropathy Numbness Outcome Pain Pathway interactions Perception Peripheral Nervous System Diseases Persistent pain Phenotype Phosphorylation Phosphorylation Inhibition Phosphorylation Site Physicians Physiological Population Potassium Potassium Channel Primary Lesion Process Property Proteins Rattus Reaction Recombinants Reflex action Regulation Research Project Grants Role Sensory Signal Transduction Site-Directed Mutagenesis Societies Sodium Spinal Ganglia Stimulus Streptozocin Symptoms System Techniques Testing Ubiquitination Unemployment Visit Western World Work Xenopus oocyte allodynia chronic pain design diabetic experience human MAPK14 protein improved neuronal excitability novel pain behavior painful neuropathy response treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Pain sensation in neuropathic pain is complex consisting of weakness, sensory deficits and numbness, reflex changes, abnormal sensations that occur either spontaneously or in reaction to external stimuli, hyperalgesia and allodynia. Perturbations in dorsal root ganglion (DRG) neuron excitability are key in precipitating neuropathic pain, especially during diabetes, the most common cause of neuropathic pain. During diabetes, the p38 mitogen-activated protein kinase (p38MAPK) signaling system is activated and when this pathway is inhibited, diabetes-induced neuropathic pain is attenuated. However, the major ion conductances involved in the neuropathic process of DRG neurons are unclear. DRG neurons possess high levels of a novel, understudied family of potassium channels called sodium-activated potassium channels (KNa). Our previous work has shown that KNa is a considerable component of the outward potassium current and is responsible for firing accommodation in DRG neurons. When we experimentally reduce the expression of these channels in DRG neurons, it produces hyperexcitability that resembles neuropathic neurons. There are two genes encoding these channels, Slack and Slick. In heterologous expression systems, the Slick and Slack subunits can co-assemble to form heteromeric channels systems with very slow activation kinetics ideal for controlling firing accommodation. Moreover, homomeric Slick channels appear to be subject to Nedd4l-dependent ubiquitination, suggesting that Slack/Slick heteromeric channels are the preferred configuration of native KNa channels. Slack and Slick also have p38MAPK consensus phosphorylation sites proximal to the sodium binding/gating region of the channels. A decrease in KNa channel activity likely ensues after diabetes-activated p38MAPK signaling. Since diabetes also affects transcriptional activities, we expect to find long-term changes in KNa channel expression in neurons. Using electrophysiological, biochemical, molecular, pain behavioral assays and a previously uncharacterized Slick knockout mouse, we will test the hypotheses: heteromeric KNa channels constrain sensory neuron hyperexcitability and neuropathic pain is associated with decreased KNa channel activity in DRG neurons. The specific aims are (1) To study the regulation of DRG KNa channels by p38MAPK (2) To investigate the subunit properties of KNa channels in DRG neurons (3) To study neuronal KNa channel activity during diabetes and compare pain behavior to Slick knockout mice. This research project will assess the involvement of KNa channels in the diabetic neuropathy. PUBLIC HEALTH RELEVANCE: Elucidating the mechanisms underlying persistent pain in peripheral neuropathy is of vital importance for future treatment strategies. This proposal is designed to determine how sodium-activated potassium channels regulate sensory neuron excitability and if they are down regulated during neuropathic pain. The conclusions of these studies may identify these channels as analgesic targets for neuropathic pain.

描述（由申请人提供）：神经性疼痛的疼痛感觉很复杂，包括无力、感觉缺陷和麻木、反射变化、自发发生或对外部刺激反应的异常感觉、痛觉过敏和异常性疼痛。背根神经节 (DRG) 神经元兴奋性的扰动是引发神经性疼痛的关键，尤其是在糖尿病期间，糖尿病是神经性疼痛的最常见原因。糖尿病期间，p38 丝裂原激活蛋白激酶 (p38MAPK) 信号系统被激活，当该通路受到抑制时，糖尿病引起的神经性疼痛就会减弱。然而，参与 DRG 神经元神经病理过程的主要离子电导尚不清楚。 DRG 神经元拥有高水平的新型、尚未研究的钾通道家族，称为钠激活钾通道 (KNa)。我们之前的工作表明，KNa 是外向钾电流的重要组成部分，负责 DRG 神经元的调节调节。当我们通过实验减少 DRG 神经元中这些通道的表达时，它会产生类似于神经病性神经元的过度兴奋。有两个基因编码这些通道：Slack 和 Slick。在异源表达系统中，Slick 和 Slack 亚基可以共同组装形成异聚通道系统，其激活动力学非常缓慢，非常适合控制发射调节。此外，同聚 Slick 通道似乎受到 Nedd4l 依赖性泛素化的影响，表明 Slack/Slick 异聚通道是天然 KNa 通道的首选配置。 Slack 和 Slick 还具有靠近通道钠结合/门控区域的 p38MAPK 共有磷酸化位点。糖尿病激活 p38MAPK 信号传导后，KNa 通道活性可能会降低。由于糖尿病也会影响转录活动，因此我们期望发现神经元中 KNa 通道表达的长期变化。使用电生理学、生化、分子、疼痛行为测定和先前未表征的 Slick 基因敲除小鼠，我们将测试以下假设：异聚 KNa 通道限制感觉神经元过度兴奋，神经性疼痛与 DRG 神经元中 KNa 通道活性降低有关。具体目标是 (1) 研究 p38MAPK 对 DRG KNa 通道的调节 (2) 研究 DRG 神经元中 KNa 通道的亚基特性 (3) 研究糖尿病期间神经元 KNa 通道的活性并比较与 Slick 基因敲除小鼠的疼痛行为。该研究项目将评估 KNa 通道在糖尿病神经病变中的参与情况。公共健康相关性：阐明周围神经病变持续性疼痛的机制对于未来的治疗策略至关重要。该提案旨在确定钠激活钾通道如何调节感觉神经元兴奋性以及它们在神经性疼痛期间是否下调。这些研究的结论可能会将这些通道确定为神经性疼痛的镇痛靶点。