Histone Deacetylases: Regulators of Cocaine Reward and Targets for Therapeutics

描述（由申请人提供）：研究染色质修饰在药物寻找行为所需的转录调节中的作用的一个诱人方面是，这些修饰可能在激活和/或维持转录过程中提供短暂和潜在稳定的表观遗传标记。这些反过来可能最终参与神经元变化所需的分子机制，为行为的持久变化服务。作为转录控制的一种表观遗传机制，染色质修饰已被证明参与维持细胞记忆（如细胞命运），并可能是长期行为改变所需的突触连接的加强和维持的基础。表观遗传学已经成为神经生物学几个领域的核心，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。本提案的研究重点是组蛋白去乙酰化，这是一种基因表达沉默的机制。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仍未得到充分研究。该资助计划的重点是研究组蛋白去乙酰化酶（HDAC） 3在可卡因诱导的条件位置偏好获得中的作用。HDAC3是脑中表达量最多的一类HDAC。该方法涉及转基因HDAC3- flox小鼠，使用表达Cre重组酶的腺相关病毒（AAV）可以产生HDAC3纯合子缺失。这种方法允许在空间和时间上限制HDAC3缺失的产生，从而避免了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。Aim 2的重点是研究一类新的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失。在这两个目标中，将使用荧光显微镜检查脑切片中的组蛋白修饰，这允许人们确定HDAC3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，本研究方案描述了一种创新的遗传和药理学方法来研究关键HDAC HDAC3在药物寻求行为的获得和消除中的作用。

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. PUBLIC HEALTH RELEVANCE: Results from this research proposal will significantly contribute to two aspects of drug seeking behavior. First, we will have a better understanding of a key molecular mechanism by which neurons make drug-induced long-lasting changes correlating with persistent changes in behavior. Second, we will explore the ability of novel inhibitors of these key molecular mechanisms to enhance the disruption of drug cue associations as a novel therapeutic approach.