Role of a medial habenula circuit and Nr4a2 in regulating cocaine action during reinstatement

项目摘要/摘要 众所周知，滥用药物会导致奖赏回路突触可塑性的长期变化， 归根结底，是行为的持续变化。了解这些变化背后的机制是关键 这是个未解决的问题。由于奖励电路和学习和记忆电路共享关键节点，新的 学习和记忆领域的发现将有可能揭示药物寻找的各个方面 行为。特别是，众所周知，基因表达是持久形式的突触所必需的。 可塑性和长期记忆的形成。最近，研究表明，表观遗传调控对 记忆巩固过程中的基因表达可以调节基因表达动态，导致令人惊讶的结果 对记忆形成的影响。例如，核中组蛋白脱乙酰基酶3(HDAC3)的抑制或缺失 伏隔核可维持Nr4a2(核孤儿受体2)的表达，与可卡因- 与上下文相关的记忆形成。Nr4a2是酪氨酸羟化酶和多巴胺的转录因子 转运体，定义多巴胺能信号转运酶。内侧缰核(MHB)，一个高度 表达HDAC3和NR4A2，其预测最近被确定为药物的主要靶点 滥用职权。我已经证明，MHB正在通过可卡因刺激恢复CPP和 MHB的激活诱导了一种重定性样的表型(特异性目标1)。此提案的F99阶段 将测试MHB内的Nr4a2是否是可卡因引发的恢复的关键调节因素(特定目标2.1)。它 将测试滥用药物引起的表观遗传改变是否会导致MHB内Nr4a2的错误调节 (具体目标2.2)。最后，使用CHIP-SEQ方法，它将设法查明Nr4a2功能的变化，该变化 致力于恢复与毒品有关的行为(具体目标2.2)。 拟议的项目还将帮助候选人阿尔贝托·L先生实现其职业目标，即成为 一家专注于研究的机构的独立调查员。该项目提供尖端技术方面的培训 研究技能，包括流式细胞仪、芯片定量聚合酶链式反应和病毒载体来操纵基因表达。此外， 拟议的研究将提供专业和技术培训，为候选人成功地 转到实验室的博士后职位(K00)，研究驱动药物寻找的神经回路 行为。加州大学欧文分校是为实现这些目标而进行培训的理想环境。 UCI是一所拥有1)鼓励合作和协作的智力环境，2)技术环境的大学 用于进行尖端研究的资源，以及3)鼓励教学培训的知名教师， 指导，以及其他必要的专业技能的发展。这里为这两个人提出的完整计划 F99和K00阶段的目的是培养一名独立的神经生物学家，为过渡做好准备 一个成功的博士后职位，并最终成为独立的终身研究员。

Project Summary/Abstract Drugs of abuse are known to cause long-term changes in the synaptic plasticity of reward circuitry and, ultimately, persistent changes in behavior. Understanding the mechanisms underlying these changes is a key open question. As the reward circuitry and the learning and memory circuitry share key nodal points, new discoveries in the learning and memory field will have the potential to shed light on aspects of drug-seeking behavior. In particular, it is well established that gene expression is required for long-lasting forms of synaptic plasticity and long-term memory formation. Very recently, studies demonstrated that epigenetic regulation of gene expression during memory consolidation can modulate gene expression dynamics, resulting in surprising effects on memory formation. For example, inhibition or deletion of histone deacetylase 3 (HDAC3) in the nucleus accumbens leads to maintained expression of Nr4a2 (nuclear orphan receptor 2), correlating with cocaine- context associated memory formation. Nr4a2 is a transcription factor for tyrosine hydroxylase and the dopamine transporter, defining enzymes of dopaminergic signaling. The medial habenula (MHb), a region that highly expresses both HDAC3 and NR4A2, and its projections have recently been identified as main targets of drugs of abuse. I have already demonstrated that the MHb is engaged by cocaine-primed reinstatement of CPP and activation of the MHb induces a reinstatetement-like phenotype (Specific Aim 1). The F99 phase of this proposal will test whether Nr4a2 within the MHb is a key regulator of cocaine-primed reinstatement (Specific Aim 2.1). It will test whether epigenetic alterations induced by drugs of abuse lead to misregulation of Nr4a2 within the MHb (Specific Aim 2.2). Lastly, using a ChIP-seq approach, it will seek to identify alterations in Nr4a2 function that engage the reinstatement of drug-associated behavior (Specific Aim 2.2). The proposed project will also help the candidate, Mr. Alberto López, achieve his career goal of becoming an independent investigator at a research-focused institution. This project provides training in cutting-edge research skill, including FACS, ChIP-qPCR, and viral vectors to manipulate gene expression. Further, the proposed studies will provide professional and technical training to prepare the candidate to successfully transition to a postdoctoral position (K00) in a laboratory that studies the neural-circuitry driving drug-seeking behavior. The University of California, Irvine is an ideal environment for training towards achieving these goals. UCI is a university with 1) an intellectual environment that encourages cooperation and collaboration, 2) technical resources to perform cutting-edge research, and 3) renowned faculty that encourage pedagogical training, mentorship, and development of other necessary professional skills. The complete plan proposed here for both the F99 and K00 phases has been designed to develop an independent neurobiologist prepared for a transition to a successful postdoctoral position and, ultimately, independent tenured investigator.