DNA Methylation in Memory Formation

描述（由申请人提供）：CNS中持久、经验依赖性功能变化的维持和延续的生化信号机制仍然是神秘的。虽然在这方面已经确定了几个有吸引力的潜在机制，包括CaMKII自磷酸化，PKM-zeta生产，AMPA受体的自动调节，转录调节机制至今很少受到关注。该项目将研究一种有效的转录调节机制，改变DNA甲基化，可能作为海马和皮质中的持久信号，以维持基因表达，细胞特性和电路功能的持续改变。我们将通过执行两个特定目标来测试这个概念的重要预测。在具体目标1中，我们将检验DNA甲基化控制体内ARC基因表达和海马位置场稳定性的假设。先前的结果已经证明，应用各种DNMT抑制剂，以及DNMT 1和3A基因的条件性缺失，导致海马LTP的缺陷和海马依赖性长期背景学习的缺陷。然而，尚不清楚海马可塑性的缺陷如何导致行为动物的记忆缺陷。在这个目标中，我们将调查DNA甲基化在细胞和系统水平上的作用，通过调查经验驱动的长期和短期的变化，在特定的海马神经元亚型使用免疫组织化学和激光捕获解剖。在另外的研究中，我们将研究DNA甲基化调节海马弧基因表达的能力，并通过研究DNA甲基化控制海马定位细胞放电模式的形成和稳定的能力。在特定目标2中，我们将检验DNA甲基化控制前扣带皮质中远程记忆存储的假设。最近几个实验室的研究表明，遥远的，即非常持久的，上下文记忆是巩固和存储在前扣带皮层。有趣的是，DNA甲基化的持久变化可能有助于稳定皮层中的远程记忆，在这个目标中，我们将测试远程记忆的形成是否与前扣带皮层中的DNA甲基化改变有关，以及是否破坏皮层DNA甲基化导致远程记忆不稳定。 公共卫生相关性：对有助于持久行为改变的信号传导机制的研究将导致确定用于药物开发的新的神经药理学靶点，并将有助于更好地理解神经行为功能的调节。该项目将特别与影响基因表达的药物可能是记忆功能障碍和促进长期行为改变的有用疗法的想法相关。

DESCRIPTION (provided by applicant): The biochemical signaling mechanisms underlying the sustenance and perpetuation of long-lasting, experience-dependent functional change in the CNS remain mysterious. Although several appealing potential mechanisms in this context have been identified, including CaMKII autophosphorylation, PKM-zeta production, and AMPA receptor auto-regulation, transcription-regulating mechanisms have received little attention to date. This Project will investigate the hypothesis that a potent transcription-regulating mechanism, altered DNA methylation, might serve as a lasting signal in the hippocampus and cortex to subserve persisting alterations in gene expression, cellular properties, and circuit function. We will test this idea by executing two Specific Aims that test important predictions of the concept. In Specific Aim 1 we will test the hypothesis that DNA methylation controls arc gene expression and hippocampal place field stability in vivo. Prior results have demonstrated that application of a variety of DNMT inhibitors, and conditional deletion of the DNMT 1 and 3A genes, leads to deficits in hippocampal LTP and deficits in hippocampus-dependent long-term contextual learning. However, it is not known how the deficits in hippocampal plasticity lead to memory deficits in the behaving animal. In this Aim we will investigate the role of DNA methylation at the cellular and systems level by investigating experience-driven long-term and short-term changes in DNA methylation in specific hippocampal neuronal subtypes using both immunohistochemistry and laser-capture dissection. In additional studies we will investigate the capacity of DNA methylation to regulate hippocampal arc gene expression, and by investigating the capacity of DNA methylation to control the formation and stabilization of hippocampal place cell firing patterns. In Specific Aim 2 we will test the hypothesis that DNA methylation controls the storage of remote memory in the anterior cingulate cortex. Recent work from several laboratories has demonstrated that remote, i.e. very long-lasting, contextual memories are consolidated and stored in the anterior cingulate cortex. It is intriguing to consider that lasting changes in DNA methylation might contribute to stabilization of remote memory in the cortex, and in this Aim we will test whether remote memory formation is associated with altered DNA methylation in the anterior cingulate cortex, and whether disrupting cortical DNA methylation leads to remote memory destabilization. PUBLIC HEALTH RELEVANCE: The study of the signaling mechanisms that contribute to long-lasting behavioral change will lead to the identification of novel neuropharmacological targets for drug development, and will contribute to a better general understanding of regulation of neurobehavioral function. This Project will specifically be relevant to the idea that drugs affecting gene expression may potentially be useful therapies for memory dysfunction and for facilitating long-term behavioral modification.