The effect of biased agonism at the Mu-Opioid receptor on drug seeking behavior

Mu-阿片受体的偏向激动对药物寻求行为的影响

• 批准号: 10590603
• 负责人: Lindsey Claire Felth
• 金额: $ 2.22万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10590603
• 关键词: ARRB2; Absence of pain sensation; Adenylate Cyclase; Adverse event; Affect; Agonist; Analgesics; Animal Model; Animals; Arrestins; Automobile Driving; Bar Codes; Biological Assay; Biology; Cell model; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Chronic; Clinic; Clinical; Codeine; Complex; Coupled; Cyclic AMP; Data; Dependence; Development; Dose; Drug Design; Drug Industry; Drug usage; Emergency Situation; Endocytosis; Endorphins; Engineering; Enkephalins; Failure; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; GTP-Binding Proteins; Glutamic Acid; Goals; Impulsivity; In Vitro; Knock-out; Knockout Mice; Ligands; Mediating; Methadone; Modeling; Morphine; Mus; Mutation; Neuronal Plasticity; Opiate Addiction; Opioid; Opioid Analgesics; Opioid Receptor; Oral; Overdose; Oxycodone; Pain; Pain management; Pathway interactions; Peptides; Persons; Pharmaceutical Preparations; Pharmacology; Phenotype; Phosphorylation; Positioning Attribute; Property; Public Health; Recommendation; Recycling; Regulatory Pathway; Rewards; Risk; Self Administration; Signal Transduction; Signaling Protein; Substance Use Disorder; System; Testing; Threonine; Time; Titrations; Training; United States; Ventilatory Depression; Vicodin; Wild Type Mouse; abuse liability; behavioral plasticity; beta-Endorphin; clinical pain; desensitization; design; drug development; drug seeking behavior; emotional distress; endogenous opioids; in vivo; insight; knockout animal; mimetics; mouse model; mu opioid receptors; mutant; novel; opioid abuse; opioid epidemic; opioid overdose; opioid use; pre-clinical; prevent; protein activation; receptor; recruit; response; side effect; small molecule; trafficking

In 2020, drug overdoses jumped by 30% with 190 people in the United States dying every day from opioid overdose. Despite their significant risks, opioids analgesics, including morphine, codeine, Vicodin and oxycontin, are still regarded as the gold standard for alleviating severe pain. All of these drugs exert their analgesic effects through activation of a G protein coupled receptor (GPCR), specifically the Gi coupled µ- Opioid receptor (MOR). Repeated use of opioids leads to the development of tolerance to the analgesic effects of these drugs. This tolerance necessitates dose escalation to maintain sufficient pain control, which, in turn, increases both the likelihood of adverse events including enhanced respiratory depression and death as well as the liability to develop opioid dependence, manifested as physical and emotional distress in the absence of drug. Importantly, dependence is a key driver of the transition from opioid use to opioid abuse yet there is little understanding of the cellular signaling properties of the MOR that promote this transition. The signaling cascade induced by endogenous opioid ligands, such as beta-endorphin, from the MOR in response provide insight, as they produce analgesia without causing the severe tolerance and dependence observed in response to the small molecule opioid drugs. One key difference between the endogenous and exogenous opioids are their ability to recruit β-arrestin-2 following G-protein activation. Counter-intuitively, the endogenous ligands are better recruiters of β-arrestin-2 and subsequently drive substantially more receptor endocytosis and recycling than opioid drugs, even though they produce less tolerance. As such, we propose that facilitating endocytosis will titrate signal transduction at MOR, emulating endorphin signal transduction, thereby reducing tolerance and dependence. To test this hypothesis, we have manipulated the ‘phosphorylation barcode’ of MOR and created an engineered receptor that recruits β-arrestin-2 and undergoes endocytosis in response to morphine. Here we will thoroughly characterize this mutant receptor in a cell-based model, including a cell- based model of tolerance and dependence. We will also assess the phenotypes of WT and β-arrestin-2-KO mice in response to morphine and methadone, the only small molecule drug that significantly recruits β- arrestin-2. We will assess tolerance and dependence in β-arrestin-2-KO in response to morphine and more importantly, methadone. We will use a novel oral operant self-administration paradigm for 16 weeks to model the transition from impulsive to compulsive drug use in both WT and β-arrestin-2-KO animals. For decades the opioid field has focused, unsuccessfully, on developing drugs that show reduced side effects. We propose that these efforts have failed because they were based on the assumption that recruitment of β-arrestin-2 produces tolerance and dependence. The studies proposed here are designed to provide substantial evidence that recruitment of β-arrestin-2 and subsequent endocytosis and recycling is beneficial. As such, they could inform drug development of novel opioid with reduced abuse liability.

2020年，药物过量跃升了30％，美国每天有190人死于Opoid 过量。尽管存在很大的风险，但阿片类药物镇痛药，包括吗啡，可待因，维科丁和 oxycontin仍然被认为是减轻严重疼痛的黄金标准。所有这些药物都施加 通过激活G蛋白偶联受体（GPCR），镇痛作用，特别是GI耦合µ- 阿片类药物接收器（MOR）。反复使用阿片类药物会导致对镇痛作用的耐受性的发展 这些药物。这种公差需要剂量升级以维持足够的疼痛控制，这反过来又 增加了不良事件的可能性，包括增强的呼吸抑郁和死亡 作为发展阿片类药物依赖的责任，在没有的情况下表现为身体和情绪困扰 药品。重要的是，依赖是从阿片类药物使用到阿片类药物滥用的关键驱动力，但几乎没有 了解促进该过渡的MOR的细胞信号传导特性。信号传导 由MOR的内源性阿片类配体诱导的级联阿片类配体诱导的响应 洞察力，因为它们产生镇痛而不会引起严重的耐受性和依赖性 对小分子阿片类药物的反应。内源性和外源性的一个关键区别 Opioid是它们在G蛋白激活后募集β-甲蛋白-2的能力。违反直觉，内源性 配体是更好的β-arrestin-2招募者，随后驱动更多受体内吞作用和 回收利用而不是阿片类药物，即使它们产生的耐受性较低。因此，我们建议促进 内吞作用将在MOR上滴定信号转导，模拟内啡肽信号转导，从而减少 宽容和依赖性。为了检验这一假设，我们操纵了 MOR并创建了一个工程的接收器，该接收器招募β-arrestin-2并经历内吞作用。 吗啡。在这里，我们将在基于细胞的模型中彻底表征该突变受体，包括细胞 - 基于耐受性和依赖性的模型。我们还将评估WT和β-arrestin-2-KO的表型 小鼠响应吗啡和方法酮，这是唯一明显募集β-的小分子药物 逮捕素2。我们将根据吗啡的响应以及更多 重要的是，Metagadone。我们将使用一种新颖的口头操作自我管理范式16周来建模 在WT和β-甲蛋白2-KO动物中，从冲动到强迫性药物的过渡。几十年来 阿片类药物领域的重点是未成功的，开发出显示副作用减少的药物。我们提出了这一点 这些努力失败了，因为它们基于这样的假设，即募集β-arrestin-2会产生 宽容和依赖性。这里提出的研究旨在提供大量证据表明 募集β-arrestin-2以及随后的内吞和回收是有益的。因此，他们可以告知 新型阿片类药物的药物开发，滥用责任减少。