Histone Deacetylases: Regulators of Cocaine Reward and Targets for Therapeutics

描述(申请人提供)：研究染色质修饰在调节药物寻找行为所需转录中的作用的诱人方面之一是，这些修饰可能提供瞬时和潜在稳定的表观遗传标记，用于激活和/或维持转录过程。反过来，这些细胞最终可能会参与神经元变化所需的分子机制，这些变化伴随着行为的长期变化。染色质修饰作为一种转录调控的表观遗传学机制，已被证明参与维持细胞记忆(如细胞命运)，并可能是加强和维持长期行为改变所需的突触连接的基础。表观遗传学已经成为神经生物学的几个领域的核心，在这些领域，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具有重要作用。这项提案中的研究重点是组蛋白去乙酰化，这是一种沉默基因表达的机制。组蛋白脱乙酰酶是长期记忆形成的关键负性调节因子，但它们在药物寻找行为中的作用在很大程度上仍未被探索。这项赠款提案的目标1的重点是研究组蛋白脱乙酰酶(HDAC)3在可卡因诱导的条件性位置偏爱获得中的作用。HDAC3是脑内表达最丰富的I类HDAC。该方法涉及到转基因的HDAC3-FLOX小鼠，在这些小鼠中，可以使用腺相关病毒(AAV)表达Cre重组酶来产生纯合的HDAC3缺失。这种方法允许产生空间和时间受限的HDAC3缺失，从而避免传统基因敲除小鼠甚至大多数转基因小鼠产生的发育和性能问题。目标2的重点是检查一类新型的HDAC抑制剂的能力，这些抑制剂对特定的HDAC具有选择性，以促进药物寻找行为的消退。在这两个目标中，脑切片中的组蛋白修饰将使用荧光显微镜进行检查，这使得人们能够确定HDAC3如何在单个神经元水平上直接/间接调节几个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学和药理学方法来研究关键的HDAC3在获得和消除寻求药物行为中的作用。

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.