The role of mTOR signaling in the cognitive impact of sleep deprivation

描述(由申请人提供)：睡眠不足会导致海马体突触可塑性和海马体依赖记忆存储的缺陷。然而，睡眠剥夺的这些效应背后的分子和细胞机制仍不清楚。几项研究表明，蛋白质合成途径在睡眠期间和睡眠剥夺后会发生变化。然而，之前没有人详细描述过蛋白质合成是如何随着睡眠或睡眠不足而改变的，也没有人描述这些改变是如何调节记忆形成的。在这个提案中，我们将探索哺乳动物雷帕霉素靶标(MTOR)信号在睡眠和睡眠介导的记忆巩固中的蛋白质合成调节作用。拟议中的实验将开发工具来分析大脑中的mTOR信号，并将为mTOR信号在睡眠依赖记忆巩固中的新作用提供直接证据。在这一应用中，提出了两个特定的目标，利用新的遗传学方法来研究睡眠剥夺如何影响mTOR信号通路，从而导致翻译减少。为了直接测试mTOR信号--特别是4E-BP活性--在睡眠剥夺诱导的损伤中的作用，我们将在特定目标1中使用病毒表达方法来确定在海马区表达野生型4E-BP是否足以恢复睡眠剥夺导致的记忆和可塑性缺陷。这种方法将允许在睡眠剥夺的情况下，仔细选择时间和细胞类型以及大脑区域特定的4E-BP表达。最后，在特定的目标2中，我们将使用病毒方法来确定在海马区表达磷酸化缺陷的4E-BP是否会模仿睡眠剥夺的影响。重要的是，这些实验将使我们能够确定mTOR信号是否在睡眠缺失所观察到的记忆和可塑性缺陷中发挥作用。

DESCRIPTION (provided by applicant): Sleep loss produces deficits in hippocampal synaptic plasticity and hippocampus-dependent memory storage. However, the molecular and cellular mechanisms that underlie these effects of sleep deprivation remain unclear. Several studies have suggested that protein synthesis pathways are altered during sleep and after periods of sleep deprivation. None however have previously described in mechanistic detail how protein synthesis is altered with sleep or sleep deprivation, nor how these alterations regulate memory formation. In this proposal, we will explore the protein synthesis regulatory role of mammalian target of rapamycin (mTOR) signaling during sleep and sleep-mediated memory consolidation. The experiments proposed will develop tools to analyze mTOR signaling in the brain and will provide direct evidence for a novel role of mTOR signaling in sleep-dependent memory consolidation. In this application, two Specific Aims are proposed that use novel genetic approaches to study how sleep deprivation affects the mTOR signaling pathway that results in reduced translation. To directly test the role of mTOR signaling - and the role of 4E-BP activity in particular - in sleep deprivation-induced impairments, we will use a viral-expression approach in Specific Aim 1 to determine if expressing wild-type 4E-BP in the hippocampus is sufficient to restore memory and plasticity deficits induced by sleep deprivation. This approach will allow for carefully timed and cell type- and brain region-specific expression of 4E-BP with sleep deprivation. Finally, in Specific Aim 2 we will use a viral approach to determine if expressing phosphorylation-defective 4E-BP in the hippocampus will mimic the effects of sleep deprivation. Importantly, these experiments will allow us to determine if mTOR signaling plays a functional role in the memory and plasticity deficits observed with sleep loss.