Ghrelin Deacylase as a Treatment for Opioid Polysubstance Abuse

生长素释放肽脱酰酶治疗阿片类多物质滥用

• 批准号: 10510245
• 负责人: CHANG-GUO ZHAN
• 金额: $ 170.09万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10510245
• 关键词: Acute; Adverse effects; Affect; Aftercare; Alcohols; Amino Acids; Amphetamines; Animals; Attenuated; Behavior; Binding; Biological Assay; Blood Circulation; Brain; Butyrylcholinesterase; Chimeric Proteins; Chronic; Cocaine; DR1 gene; Data; Dependence; Development; Disease; Dopamine; Dopamine Receptor; Down-Regulation; Drug Exposure; Drug abuse; Enzymes; Esthesia; Euphoria; Feeling; Fentanyl; G-Protein-Coupled Receptors; Gastric Acid; Heroin; High Prevalence; Human; Hydrolase; Hyperactivity; Hypesthesia; In Vitro; Ingestion; Investigation; Lead; Ligands; Literature; Methamphetamine; Morphine; National Institute of Drug Abuse; Neurons; Nicotine; Octanoic Acids; Opioid; Pathway interactions; Peptides; Perception; Pharmaceutical Preparations; Play; Presynaptic Terminals; Process; Production; Property; Proteins; Rattus; Receptor Signaling; Recombinant Proteins; Relapse; Reporting; Research; Rewards; Rodent; Rodent Model; Role; Self Administration; Side; Signal Transduction; Site-Directed Mutagenesis; Somatotropin; Stimulant; Stimulus; Stomach; Structure; Substance Use Disorder; Substance of Abuse; Synapses; System; Testing; Therapeutic; Travel; Withdrawal; Work; animal data; antagonist; base; behavioral study; conditioned place preference; deacylation; design; dopamine system; dopamine transporter; dopaminergic neuron; drug reward; effective therapy; enzyme activity; ghrelin; growth hormone secretagogue receptor; improved; in vivo; in vivo evaluation; methamphetamine effect; methamphetamine use; mutant; novel; novel therapeutic intervention; novel therapeutics; opioid use disorder; opioid user; pleasure; polysubstance abuse; polysubstance use; protein expression; protein purification; rational design; receptor; receptor expression; response; substance use; substance use treatment; success; therapeutic candidate; treatment strategy

With currently available medications for opioid use disorder (OUD), the relapse rate is very high. Further, co- use of an opioid and a stimulant, such as methamphetamine (METH), undermines success in treatment for OUD. It is highly desired to develop novel therapeutic options for treatment of OUDs including polysubstance use disorders (PSUDs). Recently reported studies have revealed an interesting role of ghrelin in drug abuse and reward-relevant behaviors. Ghrelin is known as a “growth-hormone-releasing acylated peptide from stomach”, a 28 amino-acid peptide with the third residue (Ser3) acylated by n-octanoic acid. Ghrelin is produced in the stomach, travels to the brain through blood circulation, and acts on ghrelin (or growth hormone secretagogue) receptor (GHSR) to stimulate the mesolimbic dopamine reward pathway and increase rewarding behaviors in rodents. GHSR antagonism has been shown to attenuate rewarding effects induced by various substances including METH, amphetamine, fentanyl, morphine, heroin, cocaine, nicotine, and alcohol. For example, administration of a selective GHSR antagonist significantly reduced the fentanyl‐seeking/relapse‐like behavior in rats. On the other hand, GHSR has diverse regulatory roles associated with its constitutive activity (the activity in the absence of ghrelin ligand) and, hence, GHSR antagonism could also result in unwanted adverse effects. Thus, alternative strategies targeting ghrelin itself could be more interesting. However, whether targeting ghrelin itself would be effective to attenuate the drug rewarding effects remains controversial in literature as ghrelin levels before and after treatment were not measured in previous animal studies targeting ghrelin itself. It is unclear whether any of the previously used approaches was able to decrease the ghrelin level significantly enough to attenuate the substance reward. We propose to use our recently identified ghrelin deacylase (a mutant of human butyrylcholinesterase or BChE) as a safe and effective ghrelin modulator to attenuate substance rewarding effects. Such a ghrelin modulator is expected to be as effective as a GHSR antagonist in treatment of substance use disorders (SUDs) including PSUDs, but without interacting with any brain receptors/transporters. Specifically, in this investigation, we will first evaluate the BChE mutant for its in vivo potency in modulating ghrelin and attenuating the rewarding and reinforcing effects of representative opioids (fentanyl and heroin) and their combinations with METH in various rodent models. Then, we will design and discover a new BChE mutant as a more potent ghrelin deacylase with further improved catalytic activity for ghrelin diacylation, develop its long-acting fusion protein form, and examine the long-term in vivo effects of the long-acting ghrelin deacylase. Accomplishment of this investigation will determine whether ghrelin itself is a truly effective target and whether a potent ghrelin deacylase as a ghrelin modulator is truly effective for treatment of PSUDs. If the answers are all positive, the most effective long-acting ghrelin deacylase (recombinant protein) to be tested and developed may also serve as a promising therapeutic candidate for treatment of PSUDs.

目前治疗阿片类药物使用障碍（OUD）的药物复发率非常高。此外，共同 使用阿片类药物和兴奋剂，如甲基苯丙胺 (METH)，会损害 OUD 治疗的成功。 非常需要开发新的治疗方案来治疗 OUD，包括使用多物质 疾病（PSUD）。最近报道的研究揭示了生长素释放肽在药物滥用和药物滥用中的有趣作用。 与奖励相关的行为。生长素释放肽被称为“从胃中释放生长激素的酰化肽”， 28 个氨基酸的肽，其第三个残基 (Ser3) 被正辛酸酰化。生长素释放肽 (Ghrelin) 产生于 胃，通过血液循环到达大脑，作用于生长激素释放肽（或生长激素促分泌素） 受体（GHSR）刺激中脑边缘多巴胺奖励途径并增加奖励行为 啮齿动物。 GHSR 拮抗作用已被证明可以减弱各种物质引起的奖赏效应 包括冰毒、安非他明、芬太尼、吗啡、海洛因、可卡因、尼古丁和酒精。例如， 施用选择性 GHSR 拮抗剂显着减少芬太尼寻求/复发样行为 在老鼠身上。另一方面，GHSR 具有与其构成活动（活动 在没有 ghrelin 配体的情况下），因此 GHSR 拮抗作用也可能导致不良的副作用。 因此，针对生长素释放肽本身的替代策略可能更有趣。然而，是否针对 ghrelin 其本身是否能有效减弱药物奖励效应，在文献中仍存在争议，如胃饥饿素 之前针对生长素释放肽本身的动物研究并未测量治疗前后的水平。这是 不清楚以前使用的任何方法是否能够显着降低生长素释放肽水平 足以削弱物质奖励。我们建议使用我们最近发现的生长素释放肽脱酰酶（一种突变体） 人丁酰胆碱酯酶或 BChE）作为安全有效的生长素释放肽调节剂来减弱物质 奖励效果。这种 ghrelin 调节剂预计在治疗以下疾病方面与 GHSR 拮抗剂一样有效 物质使用障碍 (SUD)，包括 PSUD，但不与任何大脑受体/转运蛋白相互作用。 具体来说，在这项研究中，我们将首先评估 BChE 突变体在体内调节的效力 胃饥饿素并减弱代表性阿片类药物（芬太尼和海洛因）的奖赏和增强作用，以及 它们在各种啮齿动物模型中与冰毒的组合。然后，我们将设计并发现一个新的BChE突变体 作为一种更有效的 ghrelin 脱酰酶，进一步提高了 ghrelin 二酰化的催化活性，开发其 长效融合蛋白形式，并检查长效生长素释放肽脱酰酶的长期体内作用。 这项调查的完成将决定ghrelin本身是否是一个真正有效的目标，以及是否 有效的生长素释放肽脱酰酶作为生长素释放肽调节剂对于治疗 PSUD 确实有效。如果答案都是 阳性，待测试和开发的最有效的长效生长素释放肽脱酰酶（重组蛋白）可能 也可作为治疗 PSUD 的有前途的候选药物。