Epitranscriptomic Regulation of Synaptic Responses to Drugs of Abuse

摘要 长期接触滥用药物会导致突触连接的持续变化，这是 以上瘾为特征的复杂行为。因此，揭示调节突触可塑性的因素是 对于理解药物诱导的神经适应的分子基础和改善我们的 治疗上瘾的能力。到目前为止，有几项研究集中在基因表达的表观遗传机制上 调节基因组，而对转录组的修改在很大程度上被忽视了。甲基化 腺苷残基(M6A)最近被证明是一种广泛的RNA修饰，在成千上万的 细胞信使核糖核酸。此外，M6A在大脑中特别丰富，它的调节一直是 与可卡因的行为和电生理反应有关。最近的研究已经开始揭示 M6A调控突触活动过程中基因表达的变化。然而，无论m6A是否有助于 药物诱导的可塑性背后的基因表达的突触变化仍然未知。在这里，我们将 探索m6A介导突触调节基因局部蛋白质产生变化的新假说 滥用药物引起的表情变化。首先，我们将确定可卡因引起的局部变化 小鼠大脑中的甲基组，并识别通过mRNA调控的潜在突触mRNAs 甲基化。其次，我们将开发新的工具来在体内鉴定瞬时M6A：蛋白质 识别新的M6A结合蛋白和可卡因诱导的动态M6A结合事件的相互作用 曝光。第三，我们将使用全球基因表达谱和基因靶向方法的组合来 确定M6A如何调节可卡因暴露后局部基因的表达。总的来说，这些研究将 探索表位转录组在控制药物诱导的基因表达变化中的新作用 揭示了调控成瘾期间发生的长期突触变化的新机制。

ABSTRACT Chronic exposure to drugs of abuse leads to persistent changes in synaptic connectivity which underlie the complex behaviors that characterize addiction. Thus, uncovering the factors that regulate synaptic plasticity is critical for understanding the molecular underpinnings of drug-induced neural adaptation and improving our ability to treat addiction. Several studies to date have focused on epigenetic mechanisms of gene expression that regulate the genome, whereas modifications to the transcriptome have been largely overlooked. Methylation of adenosine residues (m6A) has recently been shown to be a widespread RNA modification found in thousands of cellular mRNAs. Furthermore, m6A is particularly abundant within the brain, and its regulation has been implicated in the behavioral and electrophysiological response to cocaine. Recent studies have begun to reveal that m6A regulates gene expression changes during synaptic activity. However, whether m6A contributes to synaptic changes in gene expression that underlie drug-induced plasticity remains unknown. Here, we will explore the novel hypothesis that m6A-mediated changes in local protein production at the synapse regulate gene expression changes caused by drugs of abuse. First, we will identify cocaine-induced changes to the local methylome within the mouse brain and identify potential synaptic mRNAs which are regulated through mRNA methylation. Second, we will develop novel tools for the in vivo identification of transient m6A:protein interactions to identify both new m6A binding proteins as well as dynamic m6A binding events induced by cocaine exposure. Third, we will use a combination of global gene expression profiling and gene targeting approaches to determine how m6A regulates local gene expression following cocaine exposure. Collectively, these studies will explore novel roles of the epitranscriptome in controlling drug-induced gene expression changes and will likely reveal new mechanisms that regulate long-term synaptic changes that occur during addiction.