Epigenetic mechanisms of sustained transcription across cocaine abstinence

项目摘要 可卡因成瘾的特点是强迫性药物寻求和高度脆弱性复发 即使在长期禁欲之后。因此，成瘾研究领域的一个主要焦点是 研究人员已经确定了稳定的，可卡因诱导的神经适应发生在大脑奖励回路中。 转录的变化在整个禁欲过程中持续存在，但其潜在的分子机制 这种持久性的机制仍然难以捉摸。 我们最近发现转录因子Nr4a1（核受体亚家族4） 抑制可卡因奖赏和寻求行为。我们的初步数据显示，Nr4a1是一种 可卡因诱导转录的中枢调节因子，包括晚期靶基因表达 禁欲本研究的重要性因治疗剂的效用而得到加强， 调节Nr4a1和阻断小鼠可卡因自我给药，强调了巨大的 这项基础研究计划在打击吸毒成瘾方面的潜力。 鉴于组蛋白翻译后修饰（hPTM）赋予基因表达的长期变化， 稳定的细胞表型所必需的表达， 禁欲可以解释个体基因如何“记住”先前的药物暴露。我们有 先前发现Nr4a1在晚期禁欲时调节单个靶基因的hPTM。这 一项提案旨在确定细胞核中持续基因表达的机制 自愿可卡因自我给药后雄性和雌性小鼠的NAc。我们 应用新的方法对染色质和基因表达进行细胞类型特异性定量 在一个单一的样本。然后，我们使用表观遗传学方法验证了Nr4a1作用的因果机制。 在体内编辑。在本研究的结论中，我们将定义细胞类型特异性 Nr4a1调节可卡因戒断过程中稳定基因表达的机制。超出 因此，我们将应用机器学习来识别持续基因表达的新调节因子。 与可卡因成瘾有关

PROJECT SUMMARY Cocaine addiction is characterized by compulsive drug seeking and high vulnerability to relapse even after prolonged abstinence. A major focus of the field of addiction research has therefore been to identify stable, cocaine-induced neuroadaptations occurring in brain reward circuits. Transcriptional changes are known to persist throughout abstinence, yet the underlying molecular mechanisms of such persistence remain elusive. We recently discovered that the transcription factor, Nr4a1 (nuclear receptor subfamily 4) represses cocaine reward and seeking behavior. Our preliminary data show that Nr4a1 is a central regulator of cocaine-induced transcription, including target gene expression in late abstinence. The significance of this study is strengthened by the utility of therapeutic agents that regulate Nr4a1 and block mouse cocaine self-administration, underscoring the enormous potential of this basic research program in combating drug addiction. Given that histone posttranslational modifications (hPTMs) confer long-lasting changes in gene expression necessary for stable cellular phenotypes, histone modifications acquired during abstinence may explain how individual genes “remember” prior drug exposure. We have previously found that Nr4a1 regulates hPTMs at individual target genes at late abstinence. This proposal aims to define the mechanism(s) of persistent gene expression in the nucleus accumbens (NAc) of male and female mice following volitional cocaine self-administration. We apply novel methods for cell-type specific quantification of both chromatin and gene expression in a single sample. We then validate the causal mechanism of Nr4a1 action using epigenetic editing in vivo. At the conclusion of this study we will have defined the cell-type specific mechanism by which Nr4a1 regulates stable gene expression across cocaine abstinence. Beyond this, we will apply machine learning to identify novel regulators of persistent gene expression relevant to cocaine addiction.