DNA Methylation in Memory Formation

描述(由申请人提供)：中枢神经系统长期、经验依赖的功能变化的维持和永久存在的生化信号机制仍然是个谜。尽管在这方面已经发现了几种可能的机制，包括CaMKII自动磷酸化，PKM-Zeta的产生，以及AMPA受体的自动调节，但转录调控机制迄今很少受到关注。该项目将研究一种假设，即一种强大的转录调节机制，即改变的DNA甲基化，可能在海马体和皮质中充当持久的信号，以缓和基因表达、细胞特性和电路功能的持续变化。我们将通过执行两个特定的目标来测试这个想法，这两个目标测试了这个概念的重要预测。在特定的目标1中，我们将在体内验证DNA甲基化控制Arc基因表达和海马区场稳定性的假设。先前的研究结果表明，应用多种DNMT抑制剂，以及DNMT 1和3A基因的条件性缺失，会导致海马LTP和海马依赖的长期上下文学习的缺陷。然而，目前尚不清楚海马区可塑性缺陷是如何导致行为正常的动物记忆障碍的。在这一目标中，我们将通过免疫组织化学和激光捕获解剖研究经验驱动的特定海马神经元亚型DNA甲基化的长期和短期变化，在细胞和系统水平上研究DNA甲基化的作用。在进一步的研究中，我们将研究DNA甲基化调控海马ARCH基因表达的能力，以及DNA甲基化控制海马Place细胞放电模式的形成和稳定的能力。在具体目标2中，我们将测试DNA甲基化控制前扣带回皮质远程记忆存储的假设。最近几个实验室的研究表明，远距离的，即非常持久的上下文记忆被巩固并存储在前扣带回皮质中。耐人寻味的是，DNA甲基化的持续变化可能有助于皮质远程记忆的稳定，在这个目标中，我们将测试远程记忆的形成是否与前扣带回皮质DNA甲基化的改变有关，以及破坏皮质DNA甲基化是否导致远程记忆的不稳定。

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.