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励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，通过这种机制，可卡因刺激HDAC5在S279位点的瞬时去磷酸化，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引发的药物寻求恢复至关重要。此外，我们发现密切相关的酶HDAC4受到慢性可卡因暴露的相反调节，这表明这种调节在可卡因诱导的行为可塑性的发展中起重要作用。在这项资助中，我们试图表征HDAC4和HDAC5的差异调节，并测试这种调节对体内可卡因奖励和药物复发行为的重要性。具体目标1：在此目标中，我们将描述HDAC4和HDAC5在可卡因暴露下的差异磷酸化，以便更好地了解这种调节对可卡因奖励和药物寻求行为的潜在作用。我们将使用实验室中建立的条件和新试剂来评估这些hdac的磷酸化和亚细胞分布。特异性目的2：在此目的中，我们将利用病毒介导的基因传递在小鼠NAc中表达HDAC4磷酸化位点突变体。此外，我们将使用新型的HDAC4捆绑条件KO小鼠和成年NAc中病毒介导的cre表达来测试HDAC4在限制可卡因诱导的行为适应方面的必要性。具体目标3：在这个目标中，我们将扩展我们的发现，可卡因触发短暂的HDAC5核积累，以限制可卡因奖励，通过测试去磷酸化的HDAC5在可卡因成瘾最相关的模型中的作用，静脉注射可卡因自我给药。我们的初步研究结果表明，当HDAC5的去磷酸化形式表达时，可抑制可卡因原恢复。我们试图在这些研究的基础上进行扩展，以确定核HDAC5对可卡因服用和寻求、为可卡因工作的动机以及恢复寻求毒品行为的倾向的影响。

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.