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

项目总结： 认知缺陷，包括海马体依赖的记忆障碍，是衰老的一个标志。不出所料， 老年人中常见的睡眠障碍加剧了与衰老相关的认知能力下降 人口。然而，人们对这一现象背后的机制缺乏了解。 睡眠、衰老和学习的相互关联的过程。解开这些问题的一个重大挑战 机制一直是缺乏工具来实时研究细胞内和细胞外的高信号 时间分辨率。这使得很难同时观察这些信号的调制 睡眠、学习和衰老等动态过程。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 荧光寿命测光仪(Flip)使我们能够观察cAMP依赖蛋白的活性 蛋白激酶A(PKA)是一种重要的可塑性信号，参与了骨质疏松症的形成和巩固。 睡眠依赖学习，并已被证明可以增强衰老小鼠的学习能力。削皮24小时翻转 脑电和肌电同步记录海马区CA1区 (EMG)测量显示与转换相关的PKA的同步、瞬时激活 从睡到醒。由于持续时间短，这种信号以前从未在行为正常的动物身上观察到过。 因此，本研究旨在探索它在细胞和行为水平上的功能，并阐明这些功能如何 衰老小鼠的功能可能会发生变化。使用光激活腺苷环化酶(BIPAC)和穿孔补片 钳位，我将确定短暂的PKA激活是否足以导致内在兴奋性的增加 (即)，已知的PKA功能和已知的学习细胞关联。此外，通过使用BIPAC和 光激活蛋白激酶抑制肽(PA-PKI)双向调控这一暂时性PKA 信号，我的目标是确定增加这些瞬变的频率是否可以挽救海马区- 衰老小鼠的依赖学习缺陷或破坏成年小鼠完整的海马区依赖学习。 最终，我们的发现将提供对PKA如何在生理上发挥作用的更细微的理解 时间尺度以及在衰老、睡眠和学习的背景下。这项研究也将成为一个例子，说明如何 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.