Simulating Extinction Memory with Infralimbic DREADDs

使用下边缘 DREADD 模拟消退记忆

• 批准号: 8767607
• 负责人: JAMIE PETERS
• 金额: $ 17.58万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8767607
• 关键词: Accounting; Acetylcholine; Addictive Behavior; Adverse effects; Animal Model; Award; Behavior; Behavior Therapy; Behavioral Model; Blood - brain barrier anatomy; Brain; Brain region; CAV2 gene; Cholera Toxin; Clozapine; Cocaine; Cocaine Dependence; Cognitive Therapy; Data; Designer Drugs; Detection; Dorsal; Drug Addiction; Efferent Pathways; Electrodes; Engineering; Environment; Extinction (Psychology); FDA approved; Failure; Funding; GTP-Binding Proteins; Gene Transfer; Genes; Goals; Health; Human; Hypothalamic structure; Intervention; Knowledge; Laboratories; Lateral; Learning; Ligands; Mediating; Memory; Mentors; Modeling; Muscarinic Acetylcholine Receptor; Neurons; Nootropic Agents; Nucleus Accumbens; One-Step dentin bonding system; Oxides; Pathway interactions; Patients; Pharmaceutical Preparations; Pharmacological Treatment; Pharmacotherapy; Predisposition; Prefrontal Cortex; Procedures; Process; Proteins; Protocols documentation; Public Health; Rattus; Relapse; Research; Research Design; Research Personnel; Resistance; Retrieval; Rodent Model; Role; Science; Self Administration; Signal Transduction; Simulate; Site; Staging; System; Techniques; Technology; Therapeutic Effect; Training; Vaccines; Viral; Viral Vector; Virus Diseases; Work; addiction; base; career; cognitive control; combinatorial; conditioned fear; craving; drug seeking behavior; implantation; insight; interest; neural circuit; neuromechanism; novel; novel strategies; preference; programs; protein expression; public health relevance; receptor; research study; skills; success; treatment strategy; vector

DESCRIPTION (provided by applicant): Cocaine addiction is a major health problem for which pharmacological treatments are lacking. Given the failure of many attempted pharmacotherapies and vaccines to reduce relapse, novel treatment strategies are needed. One limitation to standard therapies is that they must be systemically administered, and upon crossing the blood-brain barrier, they globally activate or inhibit neurons that express the receptor they target. Given that many receptors are ubiquitously expressed in different brain regions, our ability to couple this strategy with our existing knowledge of the neural circuitry of addiction is limited. Viral-mediated gene transfer strategies are bringing us one step closer in this effort, by allowing the restricted expression of specific genes in specific neurons. The advent of Designer Receptors Activated Exclusively by Designer Drugs (DREADDs) has brought us to the forefront of this effort. These synthetic receptors are modified muscarinic receptors that are fully functional in terms of their ability to activate G-protein signaling cascades, but have been engineered to no longer respond to their endogenous ligand, acetylcholine, and instead respond to the synthetic ligand, clozapine-N-oxide (CNO). Like standard pharmacotherapies, CNO can be administered systemically and crosses the blood-brain barrier to activate DREADDs. Viral-mediated transfer of DREADDs to specific neurons thus permits the specific targeting of pharmacotherapies to discrete neural circuit components, allowing us to use existing knowledge about addiction circuitry to control drug-seeking behavior. At this stage, the viral infection process is a neurosurgical one, but the process is no more invasive than the neurosurgical implantation of deep-brain stimulating (DBS) electrodes, a strategy which is currently being employed in treatment-resistant addicted patients. Nonetheless, once the viral vector has successfully infected neurons in the brain region of interest, it can be repeatedly activated or inactivated with systemic CNO, depending on the variety of DREADD chosen. For my dissertation work at MUSC, I discovered the infralimbic cortex to be a critical brain region for the inhibition of cocaine seeking (Peters et al., J Neurosi, 2008). This observation is related to the phenomenon of extinction, a procedure akin to cognitive behavioral therapy, which can be modeled in rats and is inversely related to relapse. Evidence suggests that the formation of an extinction memory involves recruitment of the infralimbic cortex to the addiction neural circuit, and when this circuit component is active, cocaine seeking is inhibited. If we take the infralimbic cortex offline using brain-site directed pharmacological inactivation, relapse occurs. Thus, constant activity in infralimbic cortex is necessary to suppress relapse. Unfortunately, extinction memory that is formed naturally through the process of behavioral therapy is relatively weak by comparison to the strong drug memories that drive relapse. Importantly, these drug reminders drive relapse through the prelimbic cortex, which lies just dorsal to the infralimbic cortex. This underscores the importance of therapies that can selectively target the ventral, infralimbic cortex to enhance extinction, without inadvertently promoting relapse through actions in its functional opponent, prelimbic cortex. The DREADD technology provides a way to do just that. My work in conditioned fear suggests that it is possible to pharmacologically simulate extinction memory by activating infralimbic cortex (Peters et al., Science, 2010). In this K01 proposal, I will attempt to elicit similar effects on cocaine seeking using the DREADD approach, which is especially advantageous for repeatedly stimulating infralimbic cortex. Very little is known about the efferent pathways by which infralimbic cortex controls extinction of addictive behaviors. The second aim of this proposal will couple the DREADD technology with a novel, retrogradely acting CAV2 viral vector, which will permit the exclusive expression of DREADDs in specific infralimbic pathways. I already have a strong hypothesis that the nucleus accumbens shell and lateral hypothalamus may account for these infralimbic-based therapeutic effects. However, the Fos expression analyses I propose will simultaneously permit a more open-ended approach to identifying other candidate regions. Identifying the efferent pathways by which infralimbic cortex inhibits cocaine seeking will allow for more focused interventions and potentially reduce side effects. My strong mentoring team will provide me with state-of-the-art training in the proposed techniques, and I will be immersed in an enriched institutional environment. The proposed research will: 1) identify a novel treatment strategy for addiction with strong translational potential, 2) further establish my current research niche in extinction of addictive memories, and 3) lay the groundwork upon which I can build an independent research program in the addiction field.

描述（由申请人提供）：可卡因成瘾是一个主要的健康问题，缺乏药物治疗。鉴于许多尝试的药物疗法和疫苗未能减少复发，因此需要新的治疗策略。标准疗法的一个局限性是它们必须全身施用，并且在穿过血脑屏障时，它们全面激活或抑制表达它们靶向的受体的神经元。鉴于许多受体在不同的大脑区域普遍表达，我们将这种策略与我们现有的神经回路知识结合起来的能力， 成瘾是有限的。病毒介导的基因转移策略通过允许特定基因在特定神经元中的限制性表达，使我们在这一努力中更近了一步。设计师受体专门由设计师药物激活（DREADDs）的出现使我们走到了这一努力的最前沿。这些合成受体是修饰的毒蕈碱受体，其在激活G蛋白信号级联的能力方面是完全功能性的，但已被工程化以不再对其内源性配体乙酰胆碱应答，而是对合成配体氯氮平-N-氧化物（CNO）应答。与标准药物疗法一样，CNO可以全身给药，并穿过血脑屏障激活DREADD。因此，病毒介导的DREADD转移到特定的神经元，允许药物治疗的特定靶向离散的神经回路组件，使我们能够使用现有的知识成瘾回路来控制药物寻求行为。在这个阶段，病毒感染过程是一个神经外科手术，但该过程并不比脑深部刺激（DBS）电极的神经外科植入更具侵入性，这是目前用于治疗抵抗性成瘾患者的策略。尽管如此，一旦病毒载体成功感染了感兴趣的大脑区域的神经元，它可以被系统性CNO反复激活或灭活，这取决于所选择的DREADD的种类。对于我在MUSC的论文工作，我发现边缘下皮层是抑制可卡因寻求的关键大脑区域（Peters等人，J Neurosi，2008）。这一观察结果与消退现象有关，这是一种类似于认知行为疗法的过程，可以在大鼠中建模，并与复发呈负相关。有证据表明，消退记忆的形成涉及到边缘下皮层对成瘾神经回路的招募，当这个回路组件活跃时，可卡因寻求被抑制。如果我们使用大脑部位定向药理学失活来使边缘下皮层离线，复发就会发生。因此，边缘下皮层的持续活动对抑制复发是必要的。不幸的是，通过行为治疗过程自然形成的消退记忆与促使复发的强烈药物记忆相比相对较弱。重要的是，这些药物提醒物通过前边缘皮层（位于下边缘皮层的背侧）驱动复发。这就强调了 有选择性地靶向腹侧边缘下皮层以增强消退，而不会无意中通过其功能对手边缘前皮层的作用促进复发。DREADD技术提供了一种方法来做到这一点。我在条件性恐惧方面的工作表明，通过激活边缘下皮层来模拟灭绝记忆是可能的（彼得斯等人，Science，2010）。在这个K 01的建议中，我将尝试使用DREADD方法来引起对可卡因寻求的类似影响，DREADD方法对于反复刺激边缘下皮层特别有利。关于传出神经， 边缘下皮层控制成瘾行为消退的途径。该提案的第二个目的是将DREADD技术与新型的逆行作用的CAV 2病毒载体结合，其将允许DREADD在特定的边缘下通路中的排他性表达。我已经有了一个强有力的假设，即丘脑底核壳和外侧下丘脑可能解释了这些基于下丘脑的治疗效果。然而，我提出的Fos表达分析将同时允许一个更开放的方法来识别其他候选区域。确定边缘下皮层抑制可卡因寻求的传出通路将允许更有针对性的干预，并可能减少副作用。我强大的指导团队将为我提供所提出的技术的最先进的培训，我将沉浸在一个丰富的机构环境中。拟议的研究将：1）确定一种具有强大转化潜力的成瘾新治疗策略，2）进一步建立我目前在成瘾记忆消退方面的研究利基，3）奠定基础，我可以在成瘾领域建立一个独立的研究计划。