Pharmacological validation of adenylyl cyclase 1 as a drug target for chronic pain

慢性疼痛每年花费美国超过6350亿美元，然而，患者未能得到充分的缓解 从可用的药物中，并经常成为药物依赖。这些观察突出了 确定作用于独特靶点的新药物以治疗慢性疼痛。遗传学、神经生物学和临床前 研究表明腺苷酸环化酶1型（AC 1）可能提供新的药物靶点。AC 1敲除 与同窝对照相比，小鼠（AC 1-/-）表现出减少或不存在炎性和神经性疼痛。 AC 1小分子抑制剂NB 001的临床前研究显示，NB 001可减轻慢性疼痛， 反应（即炎症和神经性）。同样，我们最近也证明， 新型AC 1抑制剂ST 034307也可减轻小鼠模型中的炎性疼痛。这些研究表明 前提是AC 1是慢性疼痛抑制剂的新靶点。不幸的是，NB 001和ST 034307 存在重大问题和责任，阻碍进一步发展。为此，我们最近放映了一部 化学库收集，使我们能够确定一个嘧啶酮支架的发展新的AC 1 抑制剂的基于几个有希望的标准，该支架被优先用于命中-引线优化。初步 构效关系（SAR）研究首次揭示了亚微摩尔的化合物 在AC 1的效力，以及相对于密切相关的AC 8的选择性。此外，使用电极导线的初始体内研究 化合物在慢性疼痛的动物模型中显示活性。尽管有这些令人鼓舞的观察结果， 化合物具有极低的水溶性。我们提出了药物化学优化这一点， 支架开发有效的和选择性的AC 1活性抑制剂作为新的探针在以下具体 目的：具体目标1将利用药物化学优化的嘧啶酮骨架，开发有效的 药物样AC 1选择性分子探针。具体目标2将确定药物的药理学特异性， 使用一组体外模型测定探针分子，并探索探针活性的机制。此外，本发明还 我们将使用反复的药物化学和药理学进行体内临床前药代动力学测试。 然后，具体目标3将使用最佳分子来探索AC 1抑制剂的体内药理学活性 在炎症性疼痛、条件性位置偏爱和阿片类药物戒断的小鼠模型中。于年底 研究中，我们将为研究界提供< 100 nM AC 1效价的化学探针，> 30倍 相对于其他AC和相关CNS靶标的选择性和体内功效。这些新的探测器将提供必要的 工具来验证AC 1作为治疗慢性疼痛的新的和安全的药物靶点。

Chronic pain costs the US more than $635 billion per year, however, patients fail to receive adequate relief from the available drugs and often become drug-dependent. These observations highlight the importance for identifying new agents acting on unique targets to treat chronic pain. Genetic, neurobiological, and preclinical studies have suggested that adenylyl cyclase type 1 (AC1) may provide that new drug target. AC1 knock out mice (AC1-/-) show reduced or absent inflammatory and neuropathic pain when compared to littermate controls. Preclinical studies with a small molecule inhibitor of AC1, NB001 revealed that NB001 reduced chronic pain responses (i.e. inflammatory and neuropathic) in both mice and rats. Similarly, we have recently shown that a novel AC1 inhibitor, ST034307 also reduced inflammatory pain in a mouse model. These studies are consistent with the premise that AC1 is a new target for inhibitors of chronic pain. Unfortunately, both NB001 and ST034307 have significant issues and liabilities preventing further development. To that end, we have recently screened a chemical library collection that allowed us to identify a pyrimidinone scaffold for the development of novel AC1 inhibitors. This scaffold was prioritized for hit-to-lead optimization based on several promising criteria. Preliminary structure-activity relationship (SAR) studies have revealed for the first time compounds with sub-micromolar potency at AC1, as well as selectivity versus the closely-related AC8. Further, initial in vivo studies with a lead compound reveal activity in an animal model of chronic pain. Despite these promising observations, the lead compounds suffer from extremely low aqueous solubility. We propose medicinal chemistry optimization of this scaffold to develop potent and selective inhibitors of AC1 activity as novel probes under the following Specific Aims: Specific aim 1 will use medicinal chemistry optimization of the pyrimidinone scaffold to develop potent drug-like AC1-selective molecular probes. Specific aim 2 will establish the pharmacological specificity of the probe molecules using a set of in vitro model assays and explore the mechanisms for probe activity. Additionally, we will execute in vivo preclinical pharmacokinetic testing with iterative medicinal chemistry and pharmacology. Specific aim 3 will then use the best molecules to explore the in vivo pharmacological activity of the AC1 inhibitors in a mouse model of inflammatory pain, conditioned place preference, and opioid withdrawal. At the end of this study, we shall provide the research community with chemical probes with < 100 nM AC1 potency, > 30-fold selectivity vs other ACs and related CNS targets, and in vivo efficacy. These new probes will provide essential tools to validate AC1 as a new and safe drug target in the treatment of chronic pain.