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.

ATP门控离子通道（P2X受体）的激活剂正在与Bruce Liang博士（康涅狄格大学）合作进行合成和研究以进行心脏保护。在我们的实验室中合成的MRS2339是心肌细胞中存在的P2X4R离子通道的核苷酸激活剂。我们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盐衍生物MRS2339更稳定，并且正在体内探索。 MRS2339目前已获得私营企业的许可，以治疗心力衰竭。 P2X离子通道介导心血管，炎症和中枢神经系统中的许多有效且可能重要的生物学作用。先前的研究表明，细胞外ATP可能导致鼠，大鼠和豚鼠心室心肌细胞的离子电流。介导该电流的受体似乎是P2X受体，其中P2X4受体是重要的亚基。 P2X受体的激活导致向钠，钾和钙离子渗透的非选择性阳离子通道的打开。电流是在负膜电位下向内向内的，逆转接近0 mV，并以正势向外变。内源性细胞外ATP对该受体通道的连续激活可能会假定重要的生物学功能。在静息或负膜电位下的这种恒定激活将产生内向电流，而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通道实现其生物学作用的可能的离子机制。通过发现，心肌细胞特异性的过表达P2X4受体可以挽救心肌病的肥大和心力衰竭表型，这表明心脏肌细胞特异性的过表达（CSQ）心脏肌病模型的肥大和心力衰竭表型。然而，关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受体通道的激活是否增加对心力衰竭的进展是有益或有害的。使用几种新型的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。长期给予一种新型的核苷酸酶耐药性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，减少了心脏肥大和增加的寿命。数据表明，心脏P2X电流的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，我们确定了与MRS2339的结构相关的未加成的碳环核苷酸类似物（包括不可氢化的膦酸盐），这些核苷酸类似物代表了治疗心力衰竭的潜在候选者，这表明这是一种可行且结构广泛的方法。我们还发现，2-环己基噻吩并腺苷在心力衰竭（HF）的小鼠中具有有益的治疗作用。 我们为我们的合作者Michael Iadarola博士提供了瞬时受体潜在阳离子频道v构件1（TRPV1）的研究的化合物。 TRPV1是一种高传导性的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。在充当多模式的伤害感受器中，温度大于43°C，质子和小分子香草胶质配体（如辣椒素）。对各种刺激（热，低pH，香草素和内托苯酚）的反应能力及其在实验性炎症性和神经性疼痛模型中的敏感性和表达改变的能力，这使TRPV1成为开发新型非阿片类镇痛药的主要目标。这些主要是拮抗剂，在人类临床试验中具有无法忍受的副作用，但是最近的工作表明，在这种情况下，有效的激动剂或增强剂激动剂具有效用。在这里，我们表明二氢吡啶衍生物4,5-二甲基-3-（2-甲氧亚乙基硫硫代）-2-甲基-6-苯基-6-苯基-1,4-二羟基吡啶-3,5-二甲基二羧酸盐（MRS1477）表现为蛋白质和触发剂的阳性隔离器调节剂，这是proton and vanilloid and vanilloid activation of trpv1的阳性隔离剂。在低pH（6.0）和蛋白激酶C磷酸化的炎性模拟情况下，添加MRS1477进一步提高了已经敏化的TPRV1对辣椒素的敏感性。 MRS1477不会影响已知的香草剂拮抗剂的抑制作用，并且在存在正常的香草剂拮抗剂的情况下仍然有效地通过pH激活增强。这些结果表明，用于阳性变构调制的TRPV1上的一个不同位点可能结合内源性化合物或新型药理剂。 TRPV1敏感性的正调节表明，在组织损伤和炎症部位的高度活性伤害性神经端的钙过载可能会产生选择性镇痛。