Striatal Modulation of Epigenetic DNA Demethylation in Reward Learning

项目摘要 学习和记忆的神经表观遗传学模型认为，在学习和记忆过程中， 活性神经元以急性或慢性方式调节其放电特性，从而为细胞提供 分子记忆的形式。部分由突出的感官体验驱动，这些变化可能 在动物的整个剩余寿命中调节行为。因为毒瘾是一种慢性的 适应不良依赖于广泛的分子和生理可塑性，神经表观遗传假说， 成瘾是一个新兴的研究领域。啮齿类动物的精神刺激奖励已被证明可以调节 神经元染色质状态。在核内的动态DNA甲基化，奖励的中心枢纽 整合来自中脑的药物诱导的多巴胺能神经传递的处理也被证明是 调节可卡因敏化和情境奖励记忆。然而，人们对这个角色知之甚少， 纹状体去甲基化的机制。最近的证据表明， 涉及5-甲基胞嘧啶氧化和随后的碱基切除和修复的去甲基化 未甲基化的碱基这项提案将研究DNA去甲基化的广度和功能， 在奖励学习和基因表达中起重要作用。原代分离培养纹状体神经元 将被用来研究多巴胺对转录和相关DNA甲基化的影响。此外，本发明还 使用CRISPR技术的多重转录控制将用于去甲基化的全局调控 决定去甲基化对学习相关基因表达和可卡因奖赏作用的因素 行为最后，由于对大脑中位点特异性表观遗传动力学的作用知之甚少， 这项研究将利用一种新的融合构建体来指导纹状体中的单基因座去甲基化。的结果 该提案将扩大目前对滥用药物劫持药物的分子机制的理解。 奖励系统，并从长远来看，将提供新的见解的潜在有效性表观遗传 成瘾治疗中的操纵

Project Summary The neuroepigenetic model of learning and memory posits that a number of critical epigenetic changes in the active neuron regulate its firing properties in an acute or chronic manner and thereby provide the cell with a form of molecular memory. Driven in part by salient sensory experiences, these changes can potentially modulate behavior for the entire remaining lifespan of the animal. Because drug addiction is a state of chronic maladaptation dependent on broad molecular and physiological plasticity, the neuroepigenetic hypothesis of addiction is an emerging area of research. Psychostimulant reward in rodents has been shown to modulate the neuronal chromatin state. Dynamic DNA methylation in the nucleus accumbens, a central hub of reward processing that integrates drug-induced dopaminergic neurotransmission from the midbrain, was also shown to regulate cocaine sensitization and contextual reward memory. However, little is known about the role or mechanism of demethylation in the striatum. Recent evidence points to a sequential mechanism of demethylation involving oxidation of 5-methylcytosine and subsequent base-excision and repair to the default unmethylated base. This proposal will examine the breadth and functionality of DNA demethylation in the nucleus accumbens in reward learning and gene expression. A dissociated primary culture of striatal neurons will be used to examine the effect of dopamine on transcription and associated DNA methylation. Additionally, multiplex transcriptional control with CRISPR technologies will be used for global regulation of demethylation factors to determine the role of demethylation on learning-related gene expression and cocaine reward behavior. Finally, because the role of site-specific epigenetic dynamics in the brain is poorly understood, this study will utilize a novel fusion construct to direct single-locus demethylation in the striatum. The results of this proposal will expand the current understanding of molecular mechanisms by which drugs of abuse hijack the reward system and, in the long term, will offer novel insights into the potential effectiveness of epigenetic manipulation in addiction therapy.