Role and regulation of class IIa HDACs in cocaine addiction

描述(由申请人提供)：确定调节药物体验诱导的大脑奖赏可塑性的关键分子仍然是当前药物滥用研究的重要目标。我们最近发现了一种新的调控机制，通过可卡因刺激S279处HDAC5的瞬时去磷酸化，从而诱导这种染色质修饰酶的核积累。我们还发现，该位点的去磷酸化对于HDAC5限制可卡因奖励和减少可卡因诱导的药物寻找的恢复至关重要。此外，我们发现，与可卡因密切相关的酶HDAC4在可卡因诱导的行为可塑性的发展过程中起着重要的作用。在这项资助中，我们试图描述HDAC4和HDAC5的不同调控，并测试这一调控在体内可卡因奖励和药物复发行为中的重要性。为此，我们提出如下建议：具体目标1：在这个目标中，我们将表征HDAC4和HDAC5对可卡因暴露反应的差异磷酸化，以更好地了解这一调控在可卡因奖赏和药物寻找行为中的潜在作用。我们将使用已建立的条件和我们实验室产生的新试剂来评估这些HDAC的磷酸化和亚细胞分布。目的2：利用病毒介导的基因传递技术，在小鼠NAC中表达HDAC4的磷酸化位点突变体。此外，我们将使用新的漂白的HDAC4条件性KO小鼠和病毒介导的cre在成年NAC中的表达来测试HDAC4限制可卡因诱导的行为适应的必要性。具体目标3：在这个目标中，我们将通过在与可卡因成瘾最相关的模型--静脉注射可卡因--中测试去磷酸化的HDAC5的影响，来扩大我们的发现，即可卡因触发HDAC5的瞬时核积聚，以限制可卡因奖励。我们的初步发现显示，当去磷酸化的HDAC5表达时，可卡因-主要恢复受到抑制。我们试图扩展这些研究，以确定核HDAC5对可卡因的服用和寻求的影响，为可卡因工作的动机，以及恢复药物寻找行为的倾向。

DESCRIPTION (provided by applicant): Identifying key molecules that modulate drug experience-induced brain reward plasticity remains an important goal of current drug abuse research. We recently identified a novel regulatory mechanism by which cocaine stimulates the transient dephosphorylation of HDAC5 at S279, which induces nuclear accumulation of this chromatin-modifying enzyme. We also find that dephosphorylation of this site is critical for HDAC5 to limit cocaine reward and to reduce cocaine-primed reinstatement of drug seeking. In addition, we find that the closely-related enzyme, HDAC4, is oppositely regulated by chronic cocaine exposure, suggesting an important role for this regulation in the development of cocaine-induced behavioral plasticity. In this grant we seek to characterize the differential regulation of HDAC4 and HDAC5 and to test the importance of this regulation for cocaine reward and drug relapse behaviors in vivo. To this end, we propose the following: Specific Aim 1: In this aim, we will characterize the differential phosphorylation of HDAC4 and HDAC5 in response to cocaine exposure, in order to better understand the potential role of this regulation for cocaine reward and drug seeking behaviors. We will use established conditions and novel reagents generated in our lab to assess phosphorylation and subcellular distribution of these HDACs. Specific Aim 2: In this aim, we will utilize viral-mediated gene delivery to express phosphorylation site mutants of HDAC4 in the mouse NAc. In addition, we will use novel floxed HDAC4 conditional KO mice and viral-mediated cre expression in the adult NAc to test the necessity of HDAC4 for limiting cocaine-induced behavioral adaptations. Specific Aim 3: In this aim, we will extend our findings that cocaine triggers transient nuclear accumulation of HDAC5 to limit cocaine reward by testing the effects of the dephosphorylated HDAC5 in the most relevant model for cocaine addiction, intravenous self-administration of cocaine. Our initial findings reveal a suppression of cocaine-prime reinstatement when the dephosphorylated form of HDAC5 is expressed. We seek to expand upon these studies to determine the effect of nuclear HDAC5 on cocaine taking and seeking, motivation to work for cocaine, and propensity to reinstate drug seeking behaviors.