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）：伤害感受器基因表达的活动依赖性变化在疼痛的发病机制中发挥着至关重要的作用，这些变化是由组织或神经损伤或炎症相关的数十个基因的电活动增加引发的。已经确定了持续性疼痛的机制（例如，离子通道、受体和神经调节剂）。伤害感受器中负责活性依赖性基因调节的具体机制和转录因子在很大程度上尚不清楚，Ca2+ 依赖性转录因子在神经元的兴奋转录耦合中发挥着关键作用。由于以下原因，它是调节伤害感受器基因表达的有吸引力的候选者：首先，四种 NFAT 同工型（NFATc1-c4；NFATc3 是主要）在 DRG 神经元中表达并受其调节。其次，NFAT 对 DRG 神经元中的 [Ca2+]i 升高高度敏感（激活阈值~300 nM），这是通过电压门控 Ca2+ 通道和 TRPV1 受体介导的 Ca2+ 进入。第三，NFAT调节许多与疼痛有关的基因的表达，例如COX-2、BDNF、GluA2、 IL-6、趋化因子受体 CCR2 以及基于我们的试验数据、CGRP 和电压门控 Na+ 通道 Nav1.7。第四，我们使用 NFATc3 KO 小鼠进行的初步研究表明，NFATc3 有助于炎症诱导的疼痛敏化。表明 NFAT 在疼痛控制中发挥着重要作用，但特定 NFAT 亚型在此过程中的作用及其潜在机制尚不清楚。 NFATc3 在 DRG 神经元的活性依赖性基因调节中发挥着关键作用，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。我们将通过比较 WT 和 NFATc3 KO 的热敏化和机械敏化（完整）来研究 NFATc3 在炎症、组织和神经损伤后疼痛超敏反应中的功能意义。在目标 2 中，我们分别使用炎症（足底内完全弗氏佐剂/CFA）、组织损伤（切口后疼痛）和神经损伤（幸存神经损伤/SNI）产生的持续性疼痛模型。将通过测试去极化对表达的影响来确定 NFATc3 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WT 和 NFATc3 KO 小鼠 DRG 神经元中的 CGRP 和 Nav1.7 将增进我们对伤害感受器和疼痛敏化中活动依赖性基因调控的控制机制的理解，并有望导致缓解疼痛的新策略的开发。通过针对特定的 NFAT 同工型及其调节机制来缓解疼痛。 相关性：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动依赖性基因调控，特别是 Ca2+ 依赖性转录因子 NFAT，如何促进疼痛的发病机制。由手术创伤、炎症或神经损伤引起，可能会导致针对 NFAT 和相关信号机制的新治疗策略的开发，以减轻疼痛。