Development of Drugs Acting at Ion Channels

作用于离子通道的药物的开发

• 批准号: 8741397
• 负责人: Kenneth Alan Jacobson
• 金额: $ 6.75万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8741397
• 关键词: Absence of pain sensation; Action Potentials; Adenosine; Adverse effects; Affect; Afferent Neurons; Agonist; Binding; Biological; Biological Process; Calcium; Calcium ion; Calsequestrin; Capsaicin; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cardiovascular system; Cations; Cavia; Cells; Chronic; Clinical Trials; Collaborations; Connecticut; Data; Development; Dihydropyridines; Enhancers; Gated Ion Channel; Goals; Heart Hypertrophy; Heart failure; Human; Hydrolysis; Industry; Inflammation; Inflammatory; Ion Channel; Lead; Licensing; Ligands; Longevity; Lung; Mediating; Membrane Potentials; Modeling; Molecular Structure; Mus; Muscle Cells; Nerve Endings; Neuraxis; Nociception; Nociceptors; Nucleotidases; Nucleotides; P2X-receptor; Pain management; Peripheral Nervous System; Phenotype; Phosphorylation; Preparation; Protein Kinase C; Protons; Rattus; Receptor Activation; Regulation; Resistance; Rest; Role; Site; Structure-Activity Relationship; System; TRPV1 gene; Temperature; Therapeutic Effect; Tissues; United States National Institutes of Health; Universities; Vanilloid; Vasodilator Agents; Ventricular; Work; analog; design; dicarboxylate; dihydropyridine; drug development; extracellular; heat stimulus; in vivo; inflammatory neuropathic pain; inorganic phosphate; member; mimetics; non-opioid analgesic; novel; novel strategies; nucleotidase; nucleotide analog; overexpression; phosphonate; potassium ion; receptor; small molecule; sodium ion

Activators of ATP-gated ion channels (P2X receptors) are being synthesized and investigated for cardioprotection in collaboration with Dr. Bruce Liang (University of Connecticut). MRS2339, synthesized in our lab, is a nucleotide activator of a P2X4R ion channel present in the cardiac muscle cells. We have explored the structure activity relationships of this nucleotide. Certain phosphonate derivatives are more stable to hydrolysis than the phosphate derivative MRS2339 and are being explored in vivo. MRS2339 is currently being licensed by private industry for the treatment of heart failure. The P2X ion channels mediate a number of potent and possibly important biological effects in the cardiovascular, inflammatory, and central nervous systems. Previous studies have shown that extracellular ATP can cause an ionic current in murine, rat and guinea pig cardiac ventricular myocytes. The receptor that mediates this current appears to be a P2X receptor, of which the P2X4 receptor is an important subunit. Activation of P2X receptors leads to the opening of a nonselective cation channel permeable to sodium, potassium, and calcium ions. The current is inward at negative membrane potentials, reverses near 0 mV, and becomes outward at positive potentials. The continuous activation of this receptor channel by endogenous extracellular ATP may assume an important biological function. This constant activation under the resting or negative membrane potentials would produce an inward current, whereas its activation during depolarized portions of the action potential should lead to an outward current. These currents represent a possible ionic mechanism by which the cardiac P2X channel achieves its biological effects. A potential biologically important role of the cardiac P2X receptor was suggested by the finding that cardiac myocyte-specific overexpression of the P2X4 receptor can rescue the hypertrophic and heart failure phenotype of the calsequestrin (CSQ) model of cardiomyopathy. However, little is known regarding regulation of the cardiac P2X receptor in cardiac hypertrophy or failure. Furthermore, it is not clear whether an increased activation of the endogenous P2X receptor channel is beneficial or harmful in the progression of heart failure. The regulation of the P2X receptor-mediated ionic current and its potential role in heart failure was investigated using several novel nucleotide agonists. Chronic administration of a novel nucleotidase-resistant P2 receptor agonist MRS2339, which was capable of inducing this ionic current and was devoid of any vasodilator action, reduced cardiac hypertrophy and increased lifespan. The data suggests that an important biological function of the cardiac P2X current is to favorably modulate the progression of cardiac hypertrophy and failure. Recently we identified uncharged carbocyclic nucleotide analogues (including nonhydrolyzable phosphonates) related structurally to MRS2339, that represent potential candidates for the treatment of heart failure, suggesting this as a viable and structurally broad approach. We also found a beneficial therapeutic effect of 2-cyclohexylthio-adenosine 5-monophosphate in mice with heart failure (HF). We have provided compounds for the study of transient receptor potential cation channel subfamily V member 1 (TRPV1) to our collaborator Dr. Michael Iadarola of NIH. TRPV1 is a high-conductance, nonselective cation channel strongly expressed in nociceptive primary afferent neurons of the peripheral nervous system. In functions as a multimodal nociceptor gated by temperatures greater than 43˚C, protons, and small molecule vanilloid ligands such as capsaicin. The ability to respond to a variety of stimuli (heat, low pH, vanilloids, and endovanilloids) and its altered sensitivity and expression in experimental inflammatory and neuropathic pain models made TRPV1 a major target for the development of novel, nonopioid analgesics. These have been mostly antagonists, which have intolerable side effects in human clinical trials, but recent work shows that potent agonists or enhancers agonists have utility in this context. Here we show that the dihydropyridine derivative 4,5-diethyl-3-(2-methoxyethylthio)-2-methyl-6-phenyl-1,4-dihydropyridine-3,5-dicarboxylate (MRS1477) behaves as a positive allosteric modulator of both proton and vanilloid activation of TRPV1. Under inflammatory mimetic conditions of low pH (6.0) and protein kinase C phosphorylation, addition of MRS1477 further increased sensitivity of already sensitized TPRV1 toward capsaicin. MRS1477 does not affect inhibition by known vanilloid antagonists and remains effective in potentiating activation by pH in the presence of an orthosteric vanilloid antagonist. These results indicate a distinct site on TRPV1 for positive allosteric modulation that may bind endogenous compounds or novel pharmacological agents. Positive modulation of TRPV1 sensitivity suggests that it may be possible to produce a selective analgesia through calcium overload restricted to highly active nociceptive nerve endings at sites of tissue damage and inflammation.

与 Bruce Liang 博士（康涅狄格大学）合作，正在合成 ATP 门控离子通道（P2X 受体）激活剂，并研究其心脏保护作用。 MRS2339 是我们实验室合成的，是心肌细胞中 P2X4R 离子通道的核苷酸激活剂。我们已经探索了该核苷酸的结构活性关系。某些膦酸酯衍生物比磷酸酯衍生物 MRS2339 对水解更稳定，并且正在体内进行探索。 MRS2339 目前已获得私营企业的许可用于治疗心力衰竭。 P2X 离子通道在心血管、炎症和中枢神经系统中介导许多有效且可能重要的生物效应。先前的研究表明，细胞外 ATP 可以在小鼠、大鼠和豚鼠的心室肌细胞中引起离子电流。介导这种电流的受体似乎是P2X受体，其中P2X4受体是一个重要的亚基。 P2X 受体的激活导致可渗透钠、钾和钙离子的非选择性阳离子通道打开。膜电位为负时，电流向内，在 0 mV 附近反转，膜电位为正时，电流变为向外。内源性细胞外 ATP 对该受体通道的持续激活可能具有重要的生物学功能。这种在静息或负膜电位下的持续激活将产生内向电流，而其在动作电位的去极化部分期间的激活应导致外向电流。这些电流代表了心脏 P2X 通道实现其生物效应的可能离子机制。心肌细胞特异性 P2X4 受体过度表达可以挽救钙钙蛋白 (CSQ) 心肌病模型的肥厚和心力衰竭表型，这一发现表明心脏 P2X 受体具有潜在的重要生物学作用。然而，对于心脏肥大或衰竭中心脏 P2X 受体的调节知之甚少。此外，尚不清楚内源性 P2X 受体通道的激活增加对于心力衰竭的进展是有益还是有害。使用几种新型核苷酸激动剂研究了 P2X 受体介导的离子电流的调节及其在心力衰竭中的潜在作用。长期服用一种新型的抗核苷酸酶 P2 受体激动剂 MRS2339，它能够诱导这种离子电流，并且没有任何血管舒张作用，可减少心脏肥大并延长寿命。数据表明，心脏 P2X 电流的一个重要生物学功能是有利地调节心脏肥大和衰竭的进展。最近，我们发现了与 MRS2339 结构相关的不带电荷的碳环核苷酸类似物（包括不可水解的膦酸酯），它们代表了治疗心力衰竭的潜在候选者，表明这是一种可行且结构广泛的方法。我们还发现 2-环己基硫代腺苷 5-单磷酸对心力衰竭 (HF) 小鼠具有有益的治疗作用。 我们已向我们的合作者 NIH 的 Michael Iadarola 博士提供了用于研究瞬时受体电位阳离子通道亚家族 V 成员 1 (TRPV1) 的化合物。 TRPV1 是一种高电导、非选择性阳离子通道，在周围神经系统的伤害性初级传入神经元中强烈表达。作为多模式伤害感受器，由高于 43°C 的温度、质子和小分子香草酸配体（如辣椒素）控制。 TRPV1 对各种刺激（热、低 pH、香草醛和内香草素）做出反应的能力及其在实验性炎症和神经病理性疼痛模型中改变的敏感性和表达，使 TRPV1 成为开发新型非阿片类镇痛药的主要目标。这些大多是拮抗剂，在人体临床试验中具有无法忍受的副作用，但最近的研究表明，强效激动剂或增强剂激动剂在这方面具有实用性。在这里，我们证明二氢吡啶衍生物 4,5-二乙基-3-(2-甲氧基乙硫基)-2-甲基-6-苯基-1,4-二氢吡啶-3,5-二羧酸酯 (MRS1477) 可以作为正变构调节剂TRPV1 的质子和香草醛激活。在低 pH (6.0) 和蛋白激酶 C 磷酸化的炎症模拟条件下，添加 MRS1477 进一步增加了已致敏的 TPRV1 对辣椒素的敏感性。 MRS1477 不会影响已知的香草酸拮抗剂的抑制作用，并且在存在正位香草酸拮抗剂的情况下仍能有效增强 pH 值的激活作用。这些结果表明 TRPV1 上有一个用于正向变构调节的独特位点，该位点可能结合内源性化合物或新型药物。 TRPV1 敏感性的正向调节表明，有可能通过限制组织损伤和炎症部位高度活跃的伤害性神经末梢的钙超载来产生选择性镇痛。