The Role of Ca-dependent Transcription Factor NFAT in Pain Control

Ca 依赖性转录因子 NFAT 在疼痛控制中的作用

• 批准号: 8943179
• 负责人: Yuriy M Usachev
• 金额: $ 22.65万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8943179
• 关键词: Action Potentials; Afferent Neurons; Applications Grants; Binding; Biological Assay; Bradykinin; Brain-Derived Neurotrophic Factor; Calcineurin; Calcitonin Gene-Related Peptide; Capsaicin; Cell Nucleus; Cells; Coupling; Data; Development; Freund' s Adjuvant; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Hypersensitivity; Immune; Immunoassay; Inflammation; Injection of therapeutic agent; Injury; Interleukin-6; Ion Channel; Knock-out; Knockout Mice; Label; Lead; Luciferases; Maintenance; Mechanics; Mediating; Modeling; Monitor; Muscle Cells; Mutate; Neuromodulator Receptors; Neurons; Nociception; Nociceptors; Nuclear Localization Signal; Operative Surgical Procedures; PTGS2 gene; Pain; Pain management; Pathogenesis; Persistent pain; Play; Process; Protein Dephosphorylation; Protein Isoforms; Protein phosphatase; Public Health; Regulation; Reporter; Reporter Genes; Reverse Transcriptase Polymerase Chain Reaction; Role; Signal Transduction; Spinal Ganglia; Surgical incisions; T-Cell Activation; TRPV1 gene; Testing; Tissues; Transcription Initiation; Trauma; Western Blotting; Work; base; cell type; chemokine receptor; chronic pain; inflammatory neuropathic pain; nerve injury; novel therapeutics; nuclear factors of activated T-cells; patch clamp; prevent; receptor; response; spared nerve; transcription factor; transcription factor NF-AT c3; voltage

 DESCRIPTION (provided by applicant): Activity-dependent changes in gene expression in nociceptors play a crucial role in the pathogenesis of pain. These changes are triggered by increased electrical activity following tissue or nerve injury, or inflammation. Dozens of genes associated with the development of persistent pain have been identified (e.g., ion channels, receptors and neuromodulators). Pharmacological targeting of the expression of groups of genes that depend on common transcription factors may allow preventing the development or maintenance of chronic pain states. Yet, the specific mechanisms and transcription factors responsible for activity-dependent gene regulation in nociceptors are largely unknown. Ca2+ and Ca2+-dependent transcription factors play key roles in excitation- transcription coupling in neurons. Here, we focus on the Ca2+-dependent transcription factor NFAT as an attractive candidate for regulating gene expression in nociceptors for the following reasons. First, four NFAT isoforms (NFATc1-c4; NFATc3 being the predominant) are expressed in DRG neurons and regulated by action potentials and pain producing compounds such as capsaicin, bradykinin and NGF. Second, NFAT is highly sensitive to [Ca2+]i elevations in DRG neurons (activation trheshold~300 nM) mediated by Ca2+ entry via voltage-gated Ca2+ channels and TRPV1 receptors. Third, NFAT regulates the expression of a number of genes implicated in pain, such as COX-2, BDNF, GluA2, IL-6, chemokine receptor CCR2, and based on our pilot data, CGRP and voltage-gated Na+ channel Nav1.7. Fourth, our preliminary studies using NFATc3 KO mice indicate that NFATc3 contributes to inflammation-induced pain sensitization. Collectively, these observations suggest that NFAT plays an important role in pain control. However the roles of specific NFAT isoforms in this process and the underlying mechanisms are not known. We hypothesize that NFATc3 plays a critical role in activity-dependent gene regulation in DRG neurons, which contributes to inflammation- and injury-induced nociceptor sensitization and to the pathogenesis of inflammatory and neuropathic pain. This hypothesis will be tested in two specific aims. In Aim 1, we will examine the functional significance of NFATc3 in pain hypersensitivity following inflammation, tissue and nerve injury by comparing thermal and mechanical sensitization in WT and NFATc3 KO (complete and sensory-neuron-specific KO) mice using models of persistent pain produced by inflammation (intraplantar complete Freund's adjuvant/CFA), tissue injury (postincisional pain) and nerve injury (spared nerve injury/SNI), respectively. In Aim 2, we will establish the role of NFATc3 in regulating the expression of two important molecules implicated in pain, CGRP and Nav1.7, by testing the effects of depolarization on the expression of CGRP and Nav1.7 in DRG neurons from WT and NFATc3 KO mice. These studies will advance our understanding of the mechanisms that control activity- dependent gene regulation in nociceptors and pain sensitization, and are expected to lead to the development of new strategies for alleviating pain by targeting specific NFAT isoforms and their regulatory mechanisms. RELEVANCE: Pain management remains one of the most serious public health problems. The proposed studies will help to better understand how the activity-dependent gene regulation in primary nociceptors, and specifically, the Ca2+ -dependent transcription factor NFAT, contribute to the pathogenesis of pain caused by surgical trauma, inflammation or nerve injury, and may lead to the development of new therapeutic strategies targeting NFAT and the associated signaling mechanisms to alleviate pain.

 描述（由申请人提供）：伤害感受器中基因表达的活性依赖性变化在疼痛的发病机制中起关键作用。这些变化是由组织或神经损伤或炎症后增加的电活动触发的。已经鉴定了数十种与持续性疼痛的发展相关的基因（例如，离子通道、受体和神经调质）。依赖于共同转录因子的基因组的表达的药理学靶向可以允许预防慢性疼痛状态的发展或维持。然而，在伤害感受器中负责活性依赖性基因调控的具体机制和转录因子在很大程度上是未知的。Ca ~（2+）和Ca ~（2+）依赖性转录因子在神经元兴奋-转录偶联中起着关键作用。在这里，我们专注于Ca 2+依赖性转录因子NFAT作为一个有吸引力的候选人调节伤害感受器的基因表达，原因如下。首先，四种NFAT同种型（NFATc 1-c4; NFATc 3是主要的）在DRG神经元中表达，并由动作电位和疼痛产生化合物（如辣椒素、缓激肽和NGF）调节。第二，NFAT对DRG神经元中的[Ca 2 +]i升高高度敏感（激活阈值约300 nM），这是通过电压门控Ca 2+通道和TRPV 1受体介导的Ca 2+进入。第三，NFAT调节许多与疼痛有关的基因的表达，如考克斯-2、BDNF、GluA 2、IL-6、趋化因子受体CCR 2，以及基于我们的试验数据的CGRP和电压门控Na+通道Nav1.7。第四，我们使用NFATc 3 KO小鼠的初步研究表明，NFATc 3有助于炎症诱导的疼痛敏感化。总的来说，这些观察结果表明，NFAT在疼痛控制中起着重要作用。然而，具体的NFAT亚型在这一过程中的作用和潜在的机制是未知的。我们假设NFATc 3在DRG神经元的活性依赖性基因调控中起关键作用，这有助于炎症和损伤诱导的伤害感受器敏化以及炎症和神经病理性疼痛的发病机制。这一假设将在两个具体目标中得到检验。在目的1中，我们将通过比较WT和NFATc 3 KO中的热致敏和机械致敏来检查NFATc 3在炎症、组织和神经损伤后的疼痛超敏性中的功能意义。使用炎症产生的持续性疼痛模型的（完全和感觉神经元特异性KO）小鼠（足底完全弗氏佐剂/CFA）、组织损伤（切口后疼痛）和神经损伤（备用神经损伤/SNI）。在目的2中，我们将通过测试去极化对来自WT和NFATc 3 KO小鼠的DRG神经元中CGRP和Nav1.7表达的影响来确定NFATc 3在调节与疼痛有关的两个重要分子CGRP和Nav1.7的表达中的作用。这些研究将促进我们对控制伤害感受器和疼痛敏化中的活性依赖性基因调控的机制的理解，并有望导致通过靶向特定NFAT亚型及其调控机制来缓解疼痛的新策略的开发。 疼痛管理仍然是最严重的公共卫生问题之一。拟议的研究将有助于更好地了解初级伤害感受器中的活性依赖性基因调控，特别是Ca 2+依赖性转录因子NFAT，如何有助于手术创伤，炎症或神经损伤引起的疼痛的发病机制，并可能导致针对NFAT和相关信号机制的新治疗策略的发展，以减轻疼痛。