Development of a Human Hydrolase to Treat Cocaine Abuse and Overdose: Rat Models

开发治疗可卡因滥用和过量的人类水解酶：大鼠模型

• 批准号: 7348786
• 负责人: WILLIAM Stephen BRIMIJOIN
• 金额: $ 32.1万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-30 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7348786
• 关键词: Abate; Abstinence; Address; Adenovirus Vector; Adverse effects; Amphetamines; Attenuated; Automobile Driving; Behavior; Biology; Brain; Butyrylcholinesterase; Cardiovascular system; Cholinesterases; Cocaine; Cocaine Abuse; Cocaine Dependence; Condition; Cues; Depth; Development; Diffusion; Dopamine; Dopamine Antagonists; Dose; Drug Kinetics; Drug or chemical Tissue Distribution; End Point; Engineering; Enzymes; Evaluation; Extinction (Psychology); Female; Food; Gene Transfer; Generations; Goals; Half-Life; Heart; Hour; Human; Hydrolase; Hydrolase Gene; Injection of therapeutic agent; Intervention; Life; Liver; Maintenance; Measures; Metabolism; Methods; Modeling; Molecular; Motivation; Motor Seizures; Mus; Mutagenesis; Mutation; Neostriatum; Overdose; Patients; Pharmaceutical Preparations; Phase; Plasma; Protein Engineering; Proteins; Rattus; Recovery; Relapse; Research; Rewards; Rodent; Route; Safety; Schedule; Seizures; Self Administration; Self-Administered; Signal Transduction; Specificity; Speed; Staging; Stem cells; Structure; Testing; Therapeutic; Therapeutic Agents; Time; Toxic effect; Viral Vector; Week; Work; addiction; analog; base; behavior test; cocaine esterase; concept; design; driving behavior; drug maintenance; drug of abuse; drug seeking behavior; gene induction; gene therapy; gene transfer vector; helper-dependent adenoviral vector; male; metabolic abnormality assessment; novel; prevent; programs; response; reward circuitry; sex; success

DESCRIPTION (provided by applicant): A novel concept for treatment of cocaine abuse envisages radically accelerated metabolism of cocaine as a means of reducing drug-seeking behavior. We propose a study of "metabolic therapy" for cocaine overdose and two critical stages of cocaine addiction: steady-state maintenance of drug self-administration, and drug-primed relapse or reinstatement of drug-seeking behavior after a period of abstinence. Our therapeutic agent is a human plasma cholinesterase converted by structure-driven mutagenesis into a cocaine hydrolase (CocH) that metabolizes cocaine with exceptional speed and is far more stable than bacterial cocaine esterase. Injections of this protein hastened drug elimination 100-fold or more, prevented toxicity from a lethal dose of cocaine given up to 12 hr later, and rescued rats from overdose even after convulsive seizures commenced. In preliminary trials this hydrolase prevented reinstatement of cocaine-seeking behavior in rats that had previously self-administered the drug. These findings indicate that long-term delivery of CocH might aid in dealing with cocaine abuse and its associated toxicity. The research plan addresses this prospect with three aims. FIRST are studies to extend the surprising finding that toxicity from cocaine overdose abates in seconds after CocH injection. Extensive pharmacokinetics and mechanistic studies of dopamine transients in the neostriatum of cocaine-challenged rats will test the hypothesis that recovery from seizures reflects the creation of steep cocaine diffusion gradients between brain and plasma. SECOND are tests of CocH on the motivation for cocaine self-administration in rats working under a progressive ratio schedule for several doses of drug. Rats will also be pretreated with CocH to further investigate its ability to block cocaine-primed reinstatement of cocaine-seeking behavior. THIRD are studies on CocH gene transfer. Preliminary results with a first-generation adenoviral gene transfer vector showed that high-level transduction of cocaine hydrolase in liver blocked the induction of delta-FosB in neostriatum, a molecular signal of cocaine addiction. We now plan to test advanced helper-dependent adenoviral vectors that should sustain expression for months in the periphery and the brain. Along with viral vectors we will also examine the delivery of hydrolase by modified stem cells. Our Research Plan is based on the premise that one or more of these gene-transfer approaches will suppress drug-seeking behavior in addicted rats and also reduce the propensity for relapse. This hypothesis, if substantiated, might later be extended to human patients. Previous attempts to block such behavior, which involves activation of dopaminergic reward circuitry, have used dopamine receptor antagonists. In contrast to the many side effects of those agents, we expect our proposed treatment to lack adverse effects at doses that suppress drug seeking. Our results should increase understanding of the biology of abuse and test the concept that cocaine abuse might be effectively treated by methods that prevent drug access to targets in the brain. Program Narrative: Recent advances in protein engineering have led to a human enzyme that destroys cocaine rapidly enough to prevent it from reaching the heart or brain. Our preliminary results show that this enzyme rescues rats from lethal seizures after drug overdose and also prevent formerly addicted rats from relapsing when they get access to cocaine. This application will investigate whether direct treatment or gene therapy with this enzyme can reduce drug-seeking behavior in rats as a model for cocaine addiction in humans.

描述（由申请人提供）：一种治疗可卡因滥用的新概念设想从根本上加速可卡因的代谢，作为减少吸毒行为的一种手段。我们建议研究可卡因过量和可卡因成瘾的两个关键阶段的“代谢疗法”：药物自我给药的稳态维持，以及药物引发的戒断一段时间后药物寻求行为的复发或恢复。我们的治疗剂是一种通过结构驱动突变转化为可卡因水解酶（CocH）的人血浆胆碱酯酶，该酶以异常的速度代谢可卡因，并且比细菌可卡因酯酶稳定得多。注射这种蛋白质可使药物消除速度加快100倍或更多，防止致命剂量可卡因在12小时后产生毒性，甚至在惊厥发作后也能使大鼠免于过量服用。在初步试验中，这种水解酶可以防止先前自行服用可卡因的大鼠恢复寻求可卡因的行为。这些发现表明，长期服用CocH可能有助于处理可卡因滥用及其相关毒性。研究计划有三个目标来解决这一前景。首先，研究扩展了令人惊讶的发现，即注射CocH后，可卡因过量的毒性在几秒钟内减弱。对可卡因刺激大鼠新纹状体多巴胺瞬态的广泛药代动力学和机制研究将检验癫痫发作后的恢复反映了可卡因在大脑和血浆之间形成陡峭扩散梯度的假设。第二项是CocH对大鼠可卡因自我给药动机的测试，这些大鼠在几个剂量的药物的递进比例计划下工作。大鼠也将接受CocH预处理，以进一步研究其阻止可卡因引发的可卡因寻求行为恢复的能力。三是CocH基因转移的研究。第一代腺病毒基因转移载体的初步结果表明，肝脏中可卡因水解酶的高水平转导阻断了新纹状体中δ - fosb的诱导，这是可卡因成瘾的分子信号。我们现在计划测试高级辅助依赖腺病毒载体，它应该能在外周和大脑中维持数月的表达。除了病毒载体外，我们还将研究修饰干细胞对水解酶的递送。我们的研究计划是基于一个前提，即这些基因转移方法中的一种或多种将抑制成瘾大鼠的药物寻求行为，并减少复发的倾向。这一假设如果得到证实，以后可能会推广到人类患者身上。先前试图阻止这种行为，包括激活多巴胺能奖励回路，使用多巴胺受体拮抗剂。与这些药物的许多副作用相比，我们希望我们提出的治疗方法在抑制药物寻找的剂量下没有副作用。我们的研究结果应该增加对滥用生物学的理解，并验证这样一个概念，即可卡因滥用可以通过防止药物进入大脑目标的方法得到有效治疗。节目简介：蛋白质工程的最新进展导致了一种人体酶，它可以迅速破坏可卡因，防止可卡因到达心脏或大脑。我们的初步研究结果表明，这种酶可以使大鼠在药物过量后免于致命的癫痫发作，也可以防止以前上瘾的大鼠在获得可卡因后复发。这个应用程序将研究用这种酶的直接治疗或基因治疗是否可以减少大鼠的药物寻求行为，作为人类可卡因成瘾的模型。