Histone Deacetylases: Regulators of Cocaine Reward and Targets for Therapeutics

描述（由申请人提供）：检查染色质修饰在调节药物寻求行为所需的转录中的作用的诱人方面之一是，这些修饰可以提供瞬时和潜在稳定的表观遗传标记，以激活和/或维持转录过程。这些反过来又可能最终参与神经元变化所需的分子机制，从而使行为发生持久的变化。作为转录控制的表观遗传机制，染色质修饰已显示参与维持细胞记忆（例如，细胞命运），并可能加强和维持突触连接所需的长期行为变化的基础。表观遗传学已经成为神经生物学的几个领域的核心，研究人员发现，染色质修饰的调节在癫痫，药物成瘾，抑郁症，神经退行性疾病和记忆中起着重要作用。该提案的研究重点是组蛋白去乙酰化，这是基因表达沉默的一种机制。组蛋白去乙酰化酶是长期记忆形成的关键负调节因子，但它们在药物寻求行为中的作用在很大程度上尚未探索。本研究的目的1是研究组蛋白去乙酰化酶3在可卡因诱导的条件性位置偏爱中的作用。HDAC 3是脑中表达最丰富的I类HDAC。该方法涉及遗传修饰的HDAC 3-FLOX小鼠，其中可以使用表达Cre重组酶的腺相关病毒（AAV）产生纯合HDAC 3缺失。该方法允许产生空间和时间限制的HDAC 3缺失，其避免了由传统敲除小鼠或甚至大多数转基因小鼠引起的发育和性能问题。目的2的重点是检查一类新型HDAC抑制剂的能力，这些抑制剂对特定HDAC具有选择性，以促进药物寻求行为的消失。在这两个目标中，将使用落射荧光显微镜检查脑切片中的组蛋白修饰，这使得人们能够确定HDAC 3如何在单个神经元水平上直接/间接调节几种感兴趣的组蛋白修饰。总之，这项研究提案描述了一种创新的遗传和药理学方法，以研究关键HDAC，HDAC 3在寻求药物行为的获得和消失中的作用。

DESCRIPTION (provided by applicant): One of the alluring aspects of examining the role of chromatin modifications in modulating transcription required for drug seeking behavior is that these modifications may provide transient and potentially stable epigenetic marks in the service of activating and/or maintaining transcriptional processes. These in turn may ultimately participate in the molecular mechanisms required for neuronal changes subserving long lasting changes in behavior. As an epigenetic mechanism of transcriptional control, chromatin modification has been shown to participate in maintaining cellular memory (e.g., cell fate) and may underlie the strengthening and maintenance of synaptic connections required for long-term changes in behavior. Epigenetics has become central to several fields of neurobiology where researchers have found that regulation of chromatin modification has a significant role in epilepsy, drug addiction, depression, neurodegenerative diseases, and memory. The research in this proposal is focused on histone deacetylation, which is a mechanism by which gene expression is silenced. Histone deacetylases are key negative regulators of long-term memory formation, but their role in drug seeking behavior remains largely unexplored. The focus of Aim 1 of this grant proposal is to examine the role of histone deacetylase (HDAC) 3 in the acquisition of cocaine-induced conditioned place preference. HDAC3 is the most abundant class I HDAC expressed in brain. The approach involves genetically modified HDAC3-FLOX mice in which homozygous HDAC3 deletions can be generated using adeno-associated virus (AAV) expressing Cre recombinase. This method allows for the generation of spatially and temporally restricted HDAC3 deletions that avoid developmental and performance issues that arise from traditional knockout mice or even most transgenic mice. The focus of Aim 2 is to examine the ability of a novel class of HDAC inhibitors that are selective for specific HDACs to facilitate extinction of drug seeking behavior. In both aims, histone modifications in brain sections will be examined using epifluorescent microscopy, which allows one to determine how HDAC3 directly/indirectly regulates several histone modifications of interest at the level of individual neurons. In summary, this research proposal describes an innovative genetic and pharmacological approach to examine the role of a key HDAC, HDAC3, in acquisition and extinction of drug-seeking behavior.