Development of selective calpain-1 inhibitors for chronic pain

项目摘要 在美国历史上，从未有过开发新型非阿片类药物的未满足的医疗需求。 慢性疼痛的治疗比今天更紧迫。超过6500万美国成年人患有 慢性疼痛，导致每年近6350亿美元的医疗费用。尽管它们的功效有限， 阿片类药物具有成瘾、耐受性和运动表现受损的潜力，已成为 慢性疼痛管理，导致阿片类药物流行病肆虐整个美国的社区。 因此，迫切需要开发用于慢性疼痛管理的新型非阿片类药物疗法。这 应用程序通过利用我们的新型人工智能（AI）驱动， 药物发现平台，以开发钙蛋白酶-1的选择性抑制剂作为新型非阿片类药物治疗剂， 慢性疼痛在慢性神经病理性疼痛动物模型中的研究表明， 钙蛋白酶-1，其下调K+ Cl-协同转运蛋白活性，导致突触抑制减弱 和神经性疼痛。我们小组先前的工作也表明，药理学抑制和 钙蛋白酶-1基因敲除减轻镰状细胞小鼠慢性疼痛行为 疾病（SCD）。重要的是，钙蛋白酶-1抑制的镇痛作用不诱导耐受性副作用， 这表明钙蛋白酶-1抑制剂具有非成瘾性的潜力。通过应用我们创新的人工 智能（AI）驱动的药物发现平台筛选虚拟化学库，我们确定了四（4） 新型钙蛋白酶-1抑制剂，并验证了它们在生化测定中的功效。在此，我们建议 将我们最有效的命中化合物进展为钙蛋白酶-1选择性半胱氨酸蛋白酶的先导化合物 家族选择性、非阿片类和CNS渗透剂，在3种慢性疼痛中至少有1种中证实有效 测试的动物模型包括慢性镰状细胞病疼痛、慢性炎性疼痛和慢性炎症性疼痛。 神经性疼痛提出了三个目标，包括目标1：合成~100种我们最有效的类似物 命中化合物，并表征体外活性和选择性。成功标准：前20名细胞渗透性， 钙蛋白酶-1抑制剂，对钙蛋白酶-2具有中等选择性，对组织蛋白酶具有高度选择性， 半胱天冬酶-1，目标2：评估我们来自目标1的前20种钙蛋白酶-1抑制剂的ADME-Tox和PK特征。 成功标准：前2种CNS渗透选择性钙蛋白酶-1抑制剂，具有有利的体内PK特征，以及 目的3：确定我们的首选钙蛋白酶-1抑制剂在3种慢性疼痛中的疗效和PK/PD关系 动物模型成功：3例慢性疼痛中至少1例的机械性痛觉过敏至少减少40%。 疼痛动物模型测试。第一阶段的成功完成将产生一种新型的CNS渗透剂， 在至少1种慢性疼痛动物模型中证实了钙蛋白酶-1抑制剂的有效性。我们的整体产品 将是第一个口服，中枢神经系统作用，选择性钙蛋白酶-1抑制剂慢性疼痛。重要的是，我们的产品 将减少慢性疼痛患者的阿片类药物使用，并有助于遏制美国阿片类药物的流行。

PROJECT SUMMARY Never in the history of the United States has the unmet medical need to develop novel, non-opioid therapeutics for chronic pain been more urgent than it is today. More than 65 million US adults suffer from chronic pain, resulting in almost $635 billion in annual healthcare costs. Despite their limited efficacy, and potential for addiction, tolerance, and impaired motor performance, opioids have become a mainstay for chronic pain management, resulting in an opioid epidemic that is ravaging communities throughout the US. Thus, there is an urgent need to develop novel, non-opioid therapies for chronic pain management. This application addresses this unmet medical need by leveraging our novel artificial intelligence (AI)-driven drug discovery platform to develop selective inhibitors of calpain-1 as novel non-opioid therapeutics for chronic pain. Studies in chronic neuropathic pain animal models have shown that nerve injury overactivates calpain-1, which downregulates K+ Cl- cotransporter activity, resulting in diminished synaptic inhibition and neuropathic pain. Prior work by our group has also shown that both pharmacological inhibition and whole body genetic knockout of calpain-1 attenuates chronic pain behaviors in mouse models of sickle cell disease (SCD). Importantly, the analgesic effect of calpain-1 inhibition did not induce tolerance side effects, suggesting the potential for calpain-1 inhibitors to be non-addictive. By applying our innovative artificial intelligence (AI)-driven drug discovery platform to screen a virtual chemical library, we identified four (4) novel calpain-1 inhibitors, and validated them for efficacy in biochemical assays. Here, we propose to progress our most potent hit compound to a lead compound that is calpain-1 selective, cysteine protease family selective, non-opioid, and CNS penetrant with efficacy demonstrated in at least 1 of 3 chronic pain animal models tested, including chronic sickle cell disease pain, chronic inflammatory pain, and chronic neuropathic pain. Three aims are proposed, including Aim 1: Synthesize ~100 analogs of our most potent hit compound, and characterize in vitro activity and selectivity. Success criteria: Top 20 cell-permeable, calpain-1 inhibitors, moderately selective against calpain-2, and highly selective against cathepsins and caspase-1, Aim 2: Evaluate ADME-Tox and PK profile of our top 20 calpain-1 inhibitors from Aim 1. Success criteria: Top 2 CNS-penetrant selective calpain-1 inhibitors with favorable in vivo PK profile, and Aim 3: Determine the efficacy and PK/PD relationship of our top calpain-1 inhibitor in 3 chronic pain animal models. Success: at least 40% reduction in mechanical hyperalgesia in at least 1 of the 3 chronic pain animal models tested. Successful completion of this Phase I will yield a novel CNS-penetrant, selective calpain-1inhibitor with efficacy demonstrated in at least 1 chronic pain animal model. Our overall product would be the first, oral, CNS acting, selective calpain-1 inhibitor for chronic pain. Importantly, our product would reduce opioid usage in chronic pain patients, and help to stem the US opioid epidemic.