Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore and Bethesda, Maryland (S.L.D., C.L.P., M.F., L.L.); Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan (S.L.D.); Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark (M.A.H., B.H.); Neurobiology of Addiction Section, Integrative Neuroscience Research Branch, National Institute on Drug Abuse (C.L.P., G.F.K., L.F.V.) and Medication Development Program, National Institute on Drug Abuse Intramural Research Program (A.S., K.C.R., L.L.), National Institutes of Health, Baltimore, Maryland; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health (M.F.) and Division of Addiction Medicine, Department of Medicine, School of Medicine (L.L.), Johns Hopkins University, Baltimore, Maryland; Department of Chemistry (J.E.M., J.L.H.), Department of Biology (J.L.H.), and BioInspired Syracuse (J.L.H.), Syracuse University, Syracuse, New York; Pfizer Inc. Medicine Design, Groton, Connecticut (I.A.S.); Clinical Pharmacokinetics Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island (S.A., F.A.); Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (A.S., K.C.R.); and Center for Alcohol Addiction Studies, Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, Rhode Island (L.L.).
Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore and Bethesda, Maryland (S.L.D., C.L.P., M.F., L.L.); Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan (S.L.D.); Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark (M.A.H., B.H.); Neurobiology of Addiction Section, Integrative Neuroscience Research Branch, National Institute on Drug Abuse (C.L.P., G.F.K., L.F.V.) and Medication Development Program, National Institute on Drug Abuse Intramural Research Program (A.S., K.C.R., L.L.), National Institutes of Health, Baltimore, Maryland; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health (M.F.) and Division of Addiction Medicine, Department of Medicine, School of Medicine (L.L.), Johns Hopkins University, Baltimore, Maryland; Department of Chemistry (J.E.M., J.L.H.), Department of Biology (J.L.H.), and BioInspired Syracuse (J.L.H.), Syracuse University, Syracuse, New York; Pfizer Inc. Medicine Design, Groton, Connecticut (I.A.S.); Clinical Pharmacokinetics Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island (S.A., F.A.); Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (A.S., K.C.R.); and Center for Alcohol Addiction Studies, Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, Rhode Island (L.L.)
J Pharmacol Exp Ther. 2023 Aug;386(2):117-128. doi: 10.1124/jpet.122.001393. Epub 2023 Jan 11.
Preclinical and clinical studies have identified the ghrelin receptor [growth hormone secretagogue receptor (GHSR)1a] as a potential target for treating alcohol use disorder. A recent phase 1a clinical trial of a GHSR1a antagonist/inverse agonist, PF-5190457, in individuals with heavy alcohol drinking identified a previously undetected major hydroxy metabolite of PF-5190457, namely PF-6870961. Here, we further characterized PF-6870961 by screening for off-target interactions in a high-throughput screen and determined its in vitro pharmacodynamic profile at GHSR1a through binding and concentration-response assays. Moreover, we determined whether the metabolite demonstrated an in vivo effect by assessing effects on food intake in male and female rats. We found that PF-6870961 had no off-target interactions and demonstrated both binding affinity and inverse agonist activity at GHSR1a. In comparison with its parent compound, PF-5190457, the metabolite PF-6870961 had lower binding affinity and potency at inhibiting GHSR1a-induced inositol phosphate accumulation. However, PF-6870961 had increased inhibitory potency at GHSR1a-induced -arrestin recruitment relative to its parent compound. Intraperitoneal injection of PF-6870961 suppressed food intake under conditions of both food restriction and with ad libitum access to food in male and female rats, demonstrating in vivo activity. The effects of PF-6870961 on food intake were abolished in male and female rats knockout for GHSR, thus demonstrating that its effects on food intake are in fact mediated by the GHSR receptor. Our findings indicate that the newly discovered major hydroxy metabolite of PF-5190457 may contribute to the overall activity of PF-5190457 by demonstrating inhibitory activity at GHSR1a. SIGNIFICANCE STATEMENT: Antagonists or inverse agonists of the growth hormone secretagogue receptor (GHSR)1a have demonstrated substantial potential as therapeutics for alcohol use disorder. We here expand understanding of the pharmacology of one such GHSR1a inverse agonist, PF-5190457, by studying the safety and pharmacodynamics of its major hydroxy metabolite, PF-6870961. Our data demonstrate biased inverse agonism of PF-6870961 at GHSR1a and provide new structure-activity relationship insight into GHSR1a inverse agonism.
临床前和临床研究已经确定了胃饥饿素受体[生长激素促分泌素受体 (GHSR)1a]是治疗酒精使用障碍的潜在靶点。最近一项针对 GHSR1a 拮抗剂/反向激动剂 PF-5190457 的 1a 期临床试验，在大量饮酒的个体中发现了 PF-5190457 的一种先前未检测到的主要羟基代谢物，即 PF-6870961。在这里，我们通过高通量筛选研究了 PF-6870961 的其他靶点相互作用，并通过结合和浓度反应测定确定了其在 GHSR1a 上的体外药效学特征。此外，我们通过评估对雄性和雌性大鼠摄食的影响来确定代谢物是否具有体内作用。我们发现 PF-6870961 没有其他靶点相互作用，并且在 GHSR1a 上具有结合亲和力和反向激动剂活性。与母体化合物 PF-5190457 相比，代谢物 PF-6870961 对抑制 GHSR1a 诱导的肌醇磷酸积累的结合亲和力和效力较低。然而，PF-6870961 在抑制 GHSR1a 诱导的 -arrestin 募集方面的抑制效力高于其母体化合物。PF-6870961 腹腔注射可抑制雄性和雌性大鼠在食物限制和自由摄取食物条件下的摄食，证明了其体内活性。在雄性和雌性 GHSR 敲除大鼠中，PF-6870961 对食物摄入的影响被消除，从而表明其对食物摄入的影响实际上是由 GHSR 受体介导的。我们的研究结果表明，PF-5190457 的这种新发现的主要羟基代谢物可能通过在 GHSR1a 上表现出抑制活性来对 PF-5190457 的整体活性做出贡献。
生长激素促分泌素受体 (GHSR)1a 的拮抗剂或反向激动剂已被证明在治疗酒精使用障碍方面具有很大的潜力。我们通过研究其主要羟基代谢物 PF-6870961 的安全性和药效学，进一步了解了此类 GHSR1a 反向激动剂 PF-5190457 的药理学。我们的数据表明 PF-6870961 在 GHSR1a 上具有偏置反向激动作用，并为 GHSR1a 反向激动作用提供了新的结构-活性关系见解。
