The role of wake-associated protein kinase A transients in intrinsic plasticity and learning through aging

项目摘要： 认知缺陷，包括大脑依赖性记忆的中断，是衰老的标志。可以预见， 与衰老相关的认知能力下降因睡眠中断而加剧， 人口然而，人们对这一现象背后的机制严重缺乏了解。 睡眠、衰老和学习的相互关联的过程。解开这些谜团的一个重大挑战是 机制一直缺乏工具来研究细胞内和细胞外信号在真实的时间与高 时间分辨率这使得难以观察这些信号的调制以及这种调制。 动态过程如睡眠、学习和衰老。为了应对这些挑战，我们的实验室开发了一种 基于荧光寿命的光学传感器FLIM-AKAR，当与定制的 荧光寿命光度法（FLiP）装置允许我们观察cAMP依赖性蛋白的活性 激酶A（PKA）是一种重要的可塑性信号，参与了神经系统的形成和巩固。 睡眠依赖性学习，并已被证明可以增强衰老小鼠的学习能力。配对24小时FLiP 同步脑电图（EEG）和肌电图记录海马CA 1区 (EMG)测量结果显示，PKA的同步，瞬时激活与转换相关 从睡到醒由于其持续时间短，这种信号以前从未在行为动物中观察到过。 因此，本研究旨在探讨其在细胞和行为水平上的功能，并阐明这些功能是如何在细胞和行为水平上发挥作用的。 衰老的小鼠的功能可能会发生变化。使用光活化腺苷酸环化酶（biPAC）和穿孔贴片 钳，我将确定是否短暂PKA激活足以引起内在兴奋性的增加 (IE)PKA的一个已知功能和一个已知的学习相关细胞。此外，通过使用biPAC和 光活化蛋白激酶抑制肽（PA-PKI）双向操纵这种瞬时PKA 信号，我的目标是确定是否增加这些瞬变的频率可以挽救海马- 在衰老小鼠中的依赖性学习缺陷或在成年小鼠中破坏完整的海马依赖性学习。 最终，我们的研究结果将提供一个更细致的了解PKA如何在生理功能， 时间尺度和老化，睡眠和学习的背景下。这项研究也将作为一个例子， 利用新的光学工具可以加强我们对细胞信号动力学的理解， 与复杂的行为有关。

Project Summary: Cognitive deficits including disruptions in hippocampal-dependent memory are a hallmark of aging. Predictably, aging-associated cognitive decline is exacerbated by sleep disruptions commonly seen in the aging and elderly population. However, there is a significant lack of understanding about the mechanism behind the interconnected processes of sleep, aging and learning. One significant challenge to unraveling these mechanisms has been the lack of tools to study intracellular and extracellular signals in real time with high temporal resolution. This has made it difficult to observe the modulation of these signals alongside such dynamic processes as sleep, learning and aging. To address these challenges, our lab developed a fluorescence-lifetime based optical sensor, FLIM-AKAR, which when used in combination with a custom-built fluorescence lifetime photometry (FLiP) rig has allowed us to observe the activity of cAMP-dependent protein kinase A (PKA), an important plasticity signal that has been implicated in the formation and consolidation of sleep-dependent learning and has been shown to enhance learning in aging mice. Paring 24-hour FLiP recordings in hippocampal CA1 with simultaneous electroencephalography (EEG) and electromyography (EMG) measurements revealed a synchronized, transient activation of PKA that is associated with transitions from sleep to wake. Due to its short duration, this signal has never been observed before in a behaving animal. Thus, this study aims to explore its function on both cellular and behavioral levels and elucidate how those functions may change in aging mice. Using photoactivatable adenylate cyclase (biPAC) and perforated patch clamp, I will determine whether transient PKA activation is sufficient to cause an increase in intrinsic excitability (IE), a known function of PKA and a known cellular correlate of learning. Further, by using biPAC and photoactivatable protein kinase inhibitor peptide (PA-PKI) to bidirectionally manipulate this transient PKA signal, I aim to determine whether increasing the frequency of these transients can rescue hippocampal- dependent learning deficits in aging mice or disrupt intact hippocampal-dependent learning in adult mice. Ultimately, our findings will provide a more nuanced understanding of how PKA functions at physiologic timescales and in the context of aging, sleep, and learning. This study will also stand as an example of how taking advantage of new optical tools can bolster our understanding of how the dynamics of cell signaling relate to complex behaviors.