Regulation of Tyrosine Hydroxylase by CLOCK: Potential Mechanisms Underlying the

时钟对酪氨酸羟化酶的调节：潜在机制

• 批准号: 8397040
• 负责人: Wilbur Putney Williams
• 金额: $ 4.92万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8397040
• 关键词: Affect; Animal Model; Animals; Attenuated; Behavior; Behavioral; Binding; Binding Proteins; Biological Assay; Biological Rhythm; Bipolar Disorder; CREB1 gene; Cell Nucleus; Circadian Rhythms; Cocaine; Development; Disease; Dominant-Negative Mutation; Dopamine; Dopamine Receptor; Drug Addiction; Drug abuse; Drug usage; Elements; Enzymes; Exhibits; Genes; Genetic; Genetic Transcription; Histone Deacetylase; Link; Luciferases; Major Depressive Disorder; Manic; Mass Spectrum Analysis; Mediating; Mental disorders; Modeling; Molecular; Morphine; Mus; Mutant Strains Mice; Mutate; Mutation; National Institute of Drug Abuse; Neuronal Plasticity; Neurons; Nucleus Accumbens; Overdose; PC12 Cells; Pattern; Periodicity; Pharmaceutical Preparations; Point Mutation; Predisposition; Protein Binding; Proteins; Recruitment Activity; Regulation; Research; Rewards; Risk Factors; Role; Signal Transduction; Stimulus; Symptoms; System; Transcription Repressor/Corepressor; Transgenic Mice; Tyrosine 3-Monooxygenase; Up-Regulation; Ventral Tegmental Area; Viral; addiction; chromatin immunoprecipitation; circadian pacemaker; cocaine exposure; dopamine transporter; drug of abuse; drug reward; drug sensitivity; new therapeutic target; novel; prevent; promoter; protein activation; research study; response; reward circuitry; reward processing; transcription factor; transmission process

DESCRIPTION (provided by applicant): The alterations in neuroplasticity following drug abuse are believed to underlie the emergence of addiction, a devastating illness that affects millions worldwide. Despite intensive research into the mechanisms underlying addiction, the development of successful treatment options remains largely unfulfilled. It is now evident that disruptions in the circadian system, which coordinates the thousands of biological rhythms necessary for optimal functioning, is an underlying causative factor for psychiatric disease, including major depressive disorder, bipolar disorder and drug addiction. Indeed, circadian rhythms in drug sensitivity, seasonal patterns of drug use and overdose, and the susceptibility to addiction associated with genetic disruptions in the circadian system suggest a link between these systems. However, it is unclear how the molecular mechanisms that constitute the circadian clock impact reward circuitry central to drug dependence. Additionally, the lack of animal models that reliably capitulate the complexity of psychiatric disorders has limited our understanding of the underlying mechanisms of these illnesses. Our lab has identified and characterized a role for the circadian gene, Clock, in the regulation of reward circuitry and represents a promising candidate target for ameliorating critical risk factors in models of addiction and bipolar disorder. Transgenic mice with a dominant negative point mutation in this gene, Clock¿19, exhibit increased dopaminergic neuronal firing, upregulated TH in the VTA, increased dopaminergic tone in the NAcc and precipitates the heightened sensitivity to rewarding stimuli, including ICSS, morphine and cocaine observed in these animals. Determining the precise regulatory mechanisms by which Clock impacts reward circuitry will uncover novel therapeutic targets for the treatment of these disorders. A likely target of CLOCK in the VTA is the phosphoactive CRE-element binding protein (pCREB), the principle driver of TH transcription and is widely implicated in mediating the neuronal plasticity associated with addiction. Our lab has recently uncovered an interaction between CLOCK and pCREB at the TH promoter in the VTA providing a potential molecular link by which CLOCK regulates dopaminergic transmission and underlies the heightened dopaminergic and behavioral response to drugs of abuse in the Clock¿19mutant mouse. This proposal will 1) determine how CLOCK and pCREB interact at the TH promoter to drive rhythmic dopamine transcription 2) uncover the mechanisms underlying the inability of CLOCK¿19 to regulate dopamine transmission in the VTA and 3) determine the role of CREB signaling in Clock¿19 mice underlying the heightened sensitivity to cocaine in this model of bipolar mania. Together, these studies will bridge the gap between the circadian system and reward circuitry implicated in the development of drug dependence associated with multiple psychiatric diseases. PUBLIC HEALTH RELEVANCE: Many psychiatric illnesses, including drug addiction, are associated with disturbances in the circadian system. It is clear that these disturbances represent a potential cause, rather than a symptom of these illnesses. This connection remains correlative, as the mechanisms underlying the circadian control of reward circuitry are largely unexplored. The McClung lab has characterized a suite of neurobiolgical and behavioral alterations associated with increased dopaminergic firing and TH levels and heightened sensitivity to drugs of abuse in animals with a dominant mutation in the circadian Clock gene (Clock¿19). Determining the precise regulatory mechanisms by which Clock impacts reward circuitry will uncover novel therapeutic targets for the treatment of these disorders. These experiments aim to uncover the mechanisms by which CLOCK regulates TH in the VTA, and how the Clock¿19 mutation results in the dopaminergic upregulation central to the increased drug seeking in this model of bipolar mania, thus bridging the gap between the circadian system and reward circuitry implicated in the development of drug dependence.

描述（由申请人提供）：药物滥用后神经可塑性的改变被认为是成瘾出现的基础，成瘾是一种影响全球数百万人的毁灭性疾病。尽管深入研究了成瘾的潜在机制，但成功治疗方案的开发在很大程度上仍未实现。现在很明显，昼夜节律系统的中断，协调了最佳功能所需的数千种生物节律，是精神疾病的潜在致病因素，包括重度抑郁症，双相情感障碍和药物成瘾。事实上，药物敏感性的昼夜节律，药物使用和过量的季节性模式，以及与昼夜节律系统中遗传破坏相关的成瘾易感性表明这些系统之间存在联系。然而，目前还不清楚构成生物钟的分子机制如何影响药物依赖的奖赏回路。此外，由于缺乏可靠的动物模型来解释精神疾病的复杂性，限制了我们对这些疾病的潜在机制的理解。我们的实验室已经确定并表征了昼夜节律基因Clock在奖赏回路调节中的作用，并且代表了改善成瘾和双相情感障碍模型中关键风险因素的有希望的候选目标。在该基因中具有显性负性点突变的转基因小鼠Clock 19表现出增加的多巴胺能神经元放电，VTA中TH的上调，NAcc中多巴胺能张力的增加，并沉淀对奖励刺激的高度敏感性，包括在这些动物中观察到的ICSS，吗啡和可卡因。确定时钟影响奖励电路的精确调节机制将揭示治疗这些疾病的新治疗靶点。VTA中CLOCK的一个可能靶点是磷酸化CREB元件结合蛋白（pCREB），它是TH转录的主要驱动因子，广泛参与介导与成瘾相关的神经元可塑性。我们的实验室最近发现了CLOCK和pCREB之间的相互作用，在VTA的TH启动子提供了一个潜在的分子联系，CLOCK调节多巴胺能的传输和基础的提高多巴胺能和行为反应的药物滥用的时钟19突变小鼠。该提案将1）确定CLOCK和pCREB如何在TH启动子处相互作用以驱动节律性多巴胺转录2）揭示CLOCK <$19无法调节VTA中多巴胺传递的潜在机制和3）确定CREB信号传导在Clock <$19小鼠中的作用，其潜在作用是在该双相躁狂模型中对可卡因的敏感性增加。总之，这些研究将弥合与多种精神疾病相关的药物依赖性发展中所涉及的昼夜节律系统和奖励回路之间的差距。 公共卫生相关性：许多精神疾病，包括药物成瘾，都与昼夜节律系统紊乱有关。很明显，这些干扰是这些疾病的潜在原因，而不是症状。这种联系仍然是相关的，因为奖赏回路的昼夜节律控制机制在很大程度上尚未被探索。McClung实验室已经描述了一系列神经生物学和行为变化，这些变化与昼夜节律时钟基因（Clock ² 19）显性突变的动物中多巴胺能放电和TH水平增加以及对药物滥用敏感性增加相关。确定时钟影响奖励电路的精确调节机制将揭示治疗这些疾病的新治疗靶点。这些实验旨在揭示CLOCK调节腹侧被盖区TH的机制，以及Clock <$19突变如何导致多巴胺能上调，从而在双相躁狂模型中增加药物寻求，从而弥合昼夜节律系统和与药物依赖发展有关的奖励电路之间的差距。