Role of CB2 in Analgesic Mechanisms

CB2 在镇痛机制中的作用

• 批准号: 9127680
• 负责人: Andrea Grace Hohmann
• 金额: $ 35.1万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-15 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9127680
• 关键词: 2-arachidonylglycerol; Adverse effects; Affect; Affinity; Agonist; Analgesics; Arrestins; Astrocytes; Binding; Binding Sites; CNR2 gene; Calcium Channel; Cancer Survivor; Cannabinoids; Cell Line; Cells; Chemotherapy-Oncologic Procedure; Chemotherapy-induced peripheral neuropathy; Combined Modality Therapy; Development; Dose-Limiting; Endocannabinoids; Human; Hyperalgesia; Lead; MAGL inhibitor; MAPK3 gene; Maintenance; Mediating; Microglia; Modeling; Mus; Neurons; Neuropathy; Paclitaxel; Pain; Pathway interactions; Peripheral Nervous System Diseases; Pharmaceutical Preparations; Pharmacology; Phase; Point Mutation; Population; Pre-Clinical Model; Proteins; Receptor Signaling; Recruitment Activity; Regulation; Research; Rodent; Role; Signal Transduction; Spinal Cord; System; Testing; Traumatic Nerve Injury; Treatment Efficacy; Treatment Protocols; Work; allodynia; beta-arrestin; cell type; cellular targeting; chemotherapeutic agent; conventional therapy; drug development; effective therapy; endocannabinoid signaling; gabapentin; improved; in vitro Model; in vivo; inflammatory neuropathic pain; inflammatory pain; nerve injury; new therapeutic target; novel; novel strategies; painful neuropathy; pregabalin; public health relevance; receptor binding; research study; trafficking; unpublished works

 DESCRIPTION (provided by applicant): Cancer chemotherapy frequently causes a painful peripheral neuropathy that is dose-limiting and can be irreversible. Gabapentin is clinically used to treat diverse forms of neuropathic pain. However, the mechanism(s) responsible for its antinociceptive effects remain poorly understood. Unpublished work from our groups suggests that gabapentin suppresses neuropathic pain induced by the chemotherapeutic agent paclitaxel in rodents through interactions with CB2 cannabinoid receptors. At the cellular level, gabapentin selectively increases ability of the endocannabinoid 2-arachidonoylglycerol (2-AG) to recruit β-arrestin to CB2 receptors. These observations suggest a previously unrecognized interaction between CB2 receptors, β- arrestin/ERK1/2 signaling and gabapentin-induced antinociception. We postulate that gabapentin analgesic efficacy is due (at least in part) to a CB2-specific mechanism that involves increased β-arrestin signaling in microglia or neurons. We will thoroughly test this hypothesis by completing three Specific Aims: Aim 1 will characterize the impact of gabapentin on CB2 receptor signaling using transfected cells lines, cell lines natively expressing CB2 receptors and primary cultures of CB2-expressing cells. In addition, potential allosteric interactions between gabapentin and CB2 will be probed. Aim 2 will use conditional deletion of CB2 from neurons, microglia, and astrocytes to determine which cell type(s) express the CB2 receptors mediating gabapentin antinociception during the development and maintenance phases of paclitaxel neuropathy. Since CB2 agonists efficaciously relieve paclitaxel-induced allodynia and hyperalgesia, this approach will also be used to determine the cell type(s) mediating antinociception elicited by direct acting CB2-agonists. Aim 3 will extend the findings of the first two aims to determine if gabapentin efficacy is also CB2-mediated in other nerve injury and inflammatory pain models. The relevant cell type(s) will be determined using conditional deletion of CB2 as warranted and as described in the second specific aim. This aim will also investigate the mechanism of direct-acting CB2 agonists in these pain models using the above conditional deletion approach. Our research team combines expertise in (1) CB2 receptor binding, signaling, trafficking, and regulation, (2) cannabinoid pharmacology and antinociceptive mechanisms, and (3) mouse preclinical models of pain. Our studies suggest a highly novel and previously unrecognized intersection between CB2 receptors, endocannabinoids, and arrestin signaling that underlies the therapeutic efficacy of gabapentin. Understanding the cross-talk between these pathways is critical both for elucidating the mechanism of action of gabapentin to exploit and optimize its therapeutic efficacy and for identifying novel therapeutic targets for drug development that lack unwanted side effects of conventional treatments. Lastly, our studies will also identify the cellular targets of CB2 agonist as they relieve a variety of pathological pain states.

 描述（通过应用提供）：癌症化疗经常引起疼痛的周围神经病，这是限制剂量的，可能是不可逆的。加巴喷丁在临床上用于治疗神经性疼痛的潜水形式。然而，负责其抗伤害感受效应的机制仍然鲜为人知。我们小组的未发表的工作表明，加巴喷丁抑制了通过与CB2大麻素受体的相互作用，啮齿动物在啮齿动物中paclitaxel引起的神经性疼痛。在细胞水平上，加巴喷蛋白有选择地提高内源性大麻素2-芳基烯丙基甘油（2-AG）将β-arrestin募集到CB2受体的能力。这些观察结果表明，CB2受体，β-arrestin/erk1/2信号传导和加巴喷丁诱导的抗伤害感受之间的先前未识别的相互作用。我们假设Gabapentin镇痛效率（至少部分）归因于CB2特异性机制，该机制涉及小胶质细胞或神经元中β-arrestin信号的增加。我们将通过完成三个具体目标来彻底检验这一假设：AIM 1将使用翻译的细胞系，固定表达CB2受体的细胞系和CB2表达细胞的主要培养物来表征Gabapentin对CB2受体信号传导的影响。此外，将探测加巴喷丁与CB2之间的潜在变构相互作用。 AIM 2将使用来自神经元，小胶质细胞和星形胶质细胞的CB2有条件缺失来确定在紫杉醇Neuropathy的发育和维持阶段中介导Gabapentin抗伤害感受的CB2受体。由于CB2激动剂有效地挽救了紫杉醇诱导的异常性痛和痛觉过敏，因此该方法还将用于确定通过直接作用CB2激动剂引起的介导抗伤害感受的细胞类型。 AIM 3将扩展前两个目的的发现，以确定在其他神经损伤和炎症性疼痛模型中介导的Gabapentin效率是否也是CB2介导的。相关的单元格类型将使用CB2的条件删除如第二个特定目的所述确定。该目标还将使用上述条件缺失方法研究这些疼痛模型中直接作用CB2激动剂的机制。我们的研究团队结合了（1）CB2受体结合，信号传导，运输和调节的专业知识，（2）大麻素药理学和抗伤害感受机制，以及（3）疼痛的小鼠临床前模型。我们的研究表明，CB2受体，内源性大麻素和阻止蛋白信号之间的高度新颖且以前无法识别的相交是加巴喷丁的治疗效率的基础。了解这些途径之间的串扰对于阐明加巴喷丁的作用机理至关重要，以利用和优化其治疗有效性，并确定缺乏常规治疗副作用的药物开发的新型治疗靶标。最后，我们的研究还将确定CB2激动剂的细胞靶标，因为它们挽救了各种病理疼痛状态。