Role of dopamine-glutamate receptor heteromers and downstream nuclear calcium signaling in addiction

成瘾与其他精神疾病一样，与大脑中多巴胺（DA）和谷氨酸（Glu）介导的突触传递失衡有关。该提案的中心目标是建立靶向DA受体（DAR）和NMDA型谷氨酸受体（NMDAR）之间的串扰的方法，而不是单个受体的功能，这可能为新型、更特异和有效的治疗提供基础。纹状体中DA D1受体（D1 R）和NMDAR相互作用形成的异聚体控制突触可塑性和可卡因诱导的信号传导。我们将探索DAR/NMDAR异聚体及其下游核钙信号在成瘾发展中的作用，并确定设计新的药理学工具以对抗成瘾的关键目标。伴侣1和2建立了新的方法来检测DAR/NMDAR异聚体并阻断与它们相关的信号传导事件。D1 R/GluN 1和D2 R/GluN 2B异聚体的调制将在可卡因诱导的精神兴奋敏化和自然奖励的背景下，在整个奖励回路中进行研究。我们的初步数据表明，D1 R/GluN 1异聚体在小鼠的纹状体在精神病致敏显着增加。将开发基于病毒的方法，以区域特异性和时间控制的方式阻断异聚体的形成，以确定它们在可卡因成瘾中的功能。D1 R/GluN 1异聚体的破坏抑制了培养的纹状体中型多刺神经元（MSNs）核钙信号的产生。Partner 3已经确定，核钙瞬变是将神经元活性变化与基因转录和记忆巩固联系起来的关键事件。合作伙伴1和3将研究这个特殊的钙池在成瘾背景下的作用。合作伙伴3将研究可卡因诱导的精神过敏期间自由活动小鼠D1 R-MSN或D2 R-MSN中纹状体中核钙信号的动力学，有或没有用异聚体形成阻断剂进行预处理。核钙信号传导阻滞剂将用于建立长期行为适应，神经元形态和基因表达谱变化的因果关系。为了解决与临床前/临床研究中使用肽相关的困难，合作伙伴4将筛选特异性靶向DAR/NMDAR异聚体的非肽化合物库。将在体外和体内测试先导化合物破坏内源性异聚体、其下游核钙信号传导和可卡因成瘾相关行为改变的能力。该项目可能导致朝着确定具有治疗潜力的新靶点迈出重要一步，不仅用于成瘾，还用于各种其他精神疾病，这些疾病伴随着由于纹状体中DA和Glu介导的突触传递不平衡而导致的奖励系统功能障碍。

Addiction, like other psychiatric disorders, is associated with an imbalance of dopamine (DA) and glutamate (Glu) mediated synaptic transmission in the brain. A central goal of this proposal is to establish means of targeting the crosstalk between DA receptors (DARs) and NMDA-type glutamate receptors (NMDARs), rather than the functions of the individual receptors, which may provide the basis for novel, more specific and effective therapies. Heteromers that are formed by the interaction of DA D1 receptors (D1Rs) and NMDARs in the striatum control synaptic plasticity and cocaine-induced signaling. We will explore the role of DAR/NMDAR heteromers and their downstream nuclear calcium signaling in the development of addiction and identify key targets for the design of novel pharmacological tools to combat addiction. Partners 1 and 2 set up novel approaches to detect DAR/NMDAR heteromers and to block the signaling events associated with them. The modulation of D1R/GluN1 and D2R/GluN2B heteromers will be studied in the entire reward circuitry during cocaine-induced psychomotor sensitization and in the context of natural reward. Our preliminary data indicate a dramatic increase of D1R/GluN1 heteromers in the striatum of mice during psychomotor sensitization. Viral-based approaches will be developed to block, in a region-specific and temporally controlled manner, heteromer formation in order to determine their functions in cocaine addiction. Disruption of D1R/GluN1 heteromers inhibits the generation of nuclear calcium signals in cultured striatal medium-size spiny neurons (MSNs). Partner 3 has established that nuclear calcium transients are critical events linking changes in neuronal activity to gene transcription and memory consolidation. Partners 1 and 3 will study the role of this particular pool of calcium in the context of addiction. Partner 3 will study the dynamics of nuclear calcium signals in the striatum in D1R-MSN or D2R-MSN in freely moving mice during cocaine-induced psychomotor sensitization with or without pretreatment with blockers of heteromer formation. Blockers of nuclear calcium signaling will be used to establish causal links to long-term behavioral adaptations, changes of the neuronal morphology and gene expression profiles. To address the difficulties associated with the use of peptides in pre-clinical/clinical studies, partner 4 will screen a library for non-peptide compounds that target specifically DAR/NMDAR heteromers. Lead compounds will be tested in vitro and in vivo for their ability to disrupt endogenous heteromers, their downstream nuclear calcium signaling and cocaine addiction associated behavioral alterations. This project may lead to a major step forward towards identifying new targets with therapeutic potentials not only for addiction but also for various other psychiatric diseases that are accompanied by dysfunctions of the reward system due to an imbalance of DA and Glu mediated synaptic transmission in the striatum.