Harnessing gating-pore currents to identify novel Nav1.7 modulators

利用门孔电流识别新型 Nav1.7 调制器

• 批准号: 8259349
• 负责人: THEODORE R CUMMINS
• 金额: $ 23.1万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8259349
• 关键词: Action Potentials; Acute Pain; Address; Adverse effects; Afferent Neurons; American; Amino Acids; Analgesics; Animals; Arrhythmia; Biological Assay; Carbamazepine; Cardiac; Cells; Chimera organism; Clinical; Clinical Research; Development; Disease; Drug Delivery Systems; Effectiveness; Epilepsy; Esthesia; Exhibits; Gated Ion Channel; Generations; Genes; Goals; Health; Individual; Ion Channel; Length; Lidocaine; Measures; Medical; Monitor; Muscle; Neuraxis; Neurons; Nociception; Noise; Pain; Pain Research; Patients; Peripheral; Pharmaceutical Preparations; Pharmacology; Play; Positioning Attribute; Protein Isoforms; Proteins; Reading; Risk; Role; Screening procedure; Signal Transduction; Sodium; Sodium Channel; Sodium Channel Blockers; Specificity; System; Targeted Toxins; Techniques; Testing; Therapeutic; Therapeutic Agents; chronic neuropathic pain; clinically relevant; cost; design; high reward; inhibitor/antagonist; injured; innovation; neuronal excitability; novel; novel strategies; prevent; research and development; research study; sensor; voltage; voltage clamp; voltage gated channel

DESCRIPTION (provided by applicant): Pain is significant national health problem, costing the American public more than $100 billion each year. Voltage-gated sodium currents are essential to the generation of action potentials and contribute to the hyperexcitability of nociceptive neurons. However, although sodium channel blockers are useful for preventing acute pain, they are often associated with undesirable cardiac and CNS side effects due to their lack of isoform selectivity, limiting their therapeutic window and their effectiveness in treating chronic and neuropathic pain. Several voltage-gated sodium channels are preferentially expressed in nociceptive neurons (Nav1.7, Nav1.8 and Nav1.8). Nav1.7 in particular has been shown to play an absolutely crucial role in pain, including chronic neuropathic pain. Developing drugs that specifically target these nociceptive sodium channels could substantially increase the therapeutic armamentarium for pain. The majority of sodium channel inhibitors and modulators that have been identified interact with the sodium channel pore - because the amino acid residues lining the pore are highly conserved among the nine sodium channel genes, it has been difficult to identify pore blockers with isoform specificity. By contrast, the voltage-sensors of sodium channels show greater divergence and therefore it should be possible to develop voltage gating modifiers that target specific sodium channel isoforms. We are proposing to harness gating-pore currents to monitor sodium channel voltage-sensor function and enhance our ability to screen for voltage- gating modifiers. These gating-pore currents are currents that selectively flow through the voltage sensor domains of ion channels and provide a direct read-out of the voltage-sensor position. Importantly, they do not reflect pore activity. Two specific aims are proposed: AIM I will determine if gating-pore currents can be used to monitor the activity of voltage-sensor modulators of voltage-gated sodium channels. AIM II will determine if isolated voltage sensors or chimeric bacterial sodium channels containing a single voltage sensor of Nav1.7 can generate gating-pore currents that are sensitive to specific voltage-sensor modulators. Although we initially target Nav1.7 channels because of their importance in pain, this approach should be readily adaptable for identification and characterization of voltage-sensor modulators of other voltage-gated channels and therefore could be used to help identify isoform specific voltage-gated channel modulators that can be used in research and for the development of better therapeutics to treat a multitude of disorders of excitability such as pain, epilepsy and cardiac arrhythmias. PUBLIC HEALTH RELEVANCE: Pain is a serious medical problem that is difficult to treat in many patients. There is exceptionally strong experimental and clinical evidence indicating that drugs targeting a specific protein, Nav1.7, might be especially good at selectively blocking pain sensations. This study develops a new assay for identifying drugs that target the activity of this crucial protein.

描述(申请人提供)：疼痛是一个重要的国家健康问题，每年给美国公众造成超过1000亿美元的损失。电压门控钠电流对动作电位的产生是必不可少的，并有助于伤害性神经元的超兴奋性。然而，尽管钠通道阻滞剂有助于预防急性疼痛，但由于缺乏异构体选择性，它们经常伴随着不良的心脏和中枢神经系统副作用，限制了它们的治疗窗口和治疗慢性和神经性疼痛的有效性。几种电压门控性钠通道在伤害性神经元(Nav1.7、Nav1.8和Nav1.8)中优先表达。特别是Nav1.7，已被证明在疼痛中发挥绝对关键的作用，包括慢性神经病理性疼痛。开发专门针对这些伤害性钠通道的药物可能会大大增加治疗疼痛的武器。已确定的大多数钠通道抑制剂和调节剂都与钠通道孔相互作用--因为孔内的氨基酸残基在九个钠通道基因中高度保守，所以很难识别具有异构体特异性的孔阻滞剂。相比之下，电压传感器 钠通道的不同亚型表现出更大的分歧，因此应该有可能开发针对特定钠通道亚型的电压门控修饰剂。我们建议利用门控孔电流来监控钠通道电压传感器的功能，并增强我们筛选电压门控修饰剂的能力。这些门孔电流是选择性地流过离子通道的电压传感器域并提供电压传感器位置的直接读出的电流。重要的是，它们不能反映毛孔的活动。提出了两个具体的目标：目的I将确定门孔电流是否可以用于监测电压门控钠通道的电压传感器调制器的活动。AIM II将确定包含Nav1.7单个电压传感器的隔离电压传感器或嵌合细菌钠通道是否可以产生对特定电压传感器调制器敏感的门孔电流。虽然我们最初针对Nav1.7通道是因为它们在疼痛中的重要性，但这种方法应该很容易适应识别和表征其他电压门控通道的电压传感器调制器，因此可以用于帮助识别可用于研究和开发更好的治疗方法来治疗多种兴奋性疾病，如疼痛、癫痫和心律失常的异构体特定的电压门控通道调制器。 公共卫生相关性：疼痛是一个严重的医学问题，在许多患者中很难治疗。有非常有力的实验和临床证据表明，针对特定蛋白质Nav1.7的药物可能特别擅长选择性地阻断痛感。这项研究开发了一种新的方法来鉴定针对该活性的药物。 关键蛋白质。