Developing GPR37 activators as non-opioid pain therapeutics

摘要 强烈的伤害性感受器输入会在脊髓背角产生长期变化，这类似于 记忆印记在大脑中。因此，这种长期的变化被认为构成了“脊椎疼痛记忆” 潜在的慢性疼痛。针对“疼痛记忆维持”的慢性疼痛疗法的研究已经取得了进展 由于我们对维持这种记忆的机制了解不完全，这一研究没有取得成功。在这里，我们走 一种概念性的触发内源性“疼痛记忆擦除”机制的新方法 预防和治疗慢性疼痛。根据文献和我们的初步数据显示 用其可能的激动剂激活脊髓G蛋白偶联受体37(GPR37)逆转脊髓长 在多种动物模型中，突触突触增强和取消/抑制长时间疼痛超敏反应 提出脊髓GPR37是消除脊髓疼痛记忆的关键，因此，其激动剂将是很有前途的 疼痛疗法有效地预防/治疗慢性疼痛。这个项目是收集初步数据来验证这一点 从疼痛生物学、药物成瘾和药物发现/开发的角度通过以下几个方面提出想法 明确的目标。在目标1中，使用Tx14A，一种可能的GPR37多肽激动剂，我们将验证脊髓GPR37是一种 疼痛治疗的分子靶点和鉴定表达受体的细胞以介导疼痛记忆消除 效果。此外，我们将确定TX14A是否逆转实验诱导的背侧长期变化 角神经元对传入输入的反应。在目标2中，我们将开发GPR37细胞检测系统并执行 高通量筛选(HTS)测试小分子库中的化合物以识别潜在的可用药 GPR37激动剂。使用药物化学方法，我们还将设计、合成和早期优化 基于TX14A和GPR37 HTS‘HITS’的新小肽和模拟肽小分子。在《目标3》中， 我们将开发和优化临床前体内测试范例，以简化止痛药的评估 新的GPR37激动剂的疗效和滥用易感性。 通过这些目标获得的初步结果将为后续的团队研究奠定基础 U19应用程序响应RFA-NS-21-015。具体而言，目标1-3的结果将是三个目标的基础 U19应用中的研究组成部分：1)治疗目标和基础生物学的验证，2) 测试开发、筛选和优化，以及3)动物模型和/或验证的开发和验证 结果衡量标准。

ABSTRACT Intense nociceptor inputs produce long-term changes in the spinal cord dorsal horn, which resemble the memory engram in the brain. Thus, such long-term changes are suggested to constitute ‘spinal pain memory’ underlying chronic pain. Efforts to develop chronic pain therapies targeting ‘pain memory maintenance’ have been unsuccessful due to our incomplete understanding of mechanisms maintaining this memory. Here we take a conceptually novel approach of triggering endogenous ‘pain memory erasure’ mechanisms for effective prevention and treatment of chronic pain. Based on the literature and our preliminary data demonstrating that activating the spinal G protein-coupled receptor 37 (GPR37) using its putative agonists reverses spinal long- term synaptic potentiation and abolishes/curtails long-lasting pain hypersensitivity in multiple animal models, we propose that spinal GPR37 is the key to erasing spinal pain memory and therefore, its agonists will be promising pain therapeutics effectively prevent/treat chronic pain. This project is to collect preliminary data validating this idea from pain biology, drug addiction, and drug discovery/development perspectives through the following Specific Aims. In Aim 1, using TX14A, a putative peptide agonist for GPR37, we will validate spinal GPR37 as a molecular target for pain therapy and identify cells expressing the receptor to mediate the pain memory erasure effect. Additionally, we will determine if TX14A reverses experimentally induced long-term changes in dorsal horn neuronal responses to afferent inputs. In Aim 2, we will develop a GPR37 cellular assay system and perform a high throughput screening (HTS) testing compounds in small molecule libraries to identify potential druggable GPR37 agonists. Using medicinal chemistry approaches, we will also design, synthesize, and early optimize new small peptide and peptidomimetic small molecules based on TX14A and the GPR37 HTS ‘hits’. In Aim 3, we will develop and optimize preclinical in vivo testing paradigms to streamline the assessment of analgesic efficacy and abuse liability of new GPR37 agonists. The preliminary results obtained through these Aims will lay the groundwork for a subsequent Team Research U19 application responding to RFA-NS-21-015. Specifically, the results of Aims 1-3 will be the basis of the three Research Components in the U19 application: 1) Validation of Therapeutic Target and Underlying Biology, 2) Assay Development, Screening and Optimization, and 3) Development and Validation of Animal Models and/or Outcome Measures.