MAPK signaling: gates, oscillators and circadian timing

MAPK 信号：门、振荡器和昼夜节律计时

基本信息

批准号：
10375498
负责人：
KARI RENE HOYT
金额：
$ 46.68万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-01 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10375498
关键词：
Address Affect Animal Model Behavior Behavioral Biological Rhythm Cell physiology Cells Central Nervous System Diseases Circadian Dysregulation Circadian Rhythms Complex Coupled Data Development Dissociation Event Gene Mutation Generations Genetic Transcription Goals Health Hour Human Hypothalamic structure Knock-out Knockout Mice Light MAP Kinase Gene Mitogen-Activated Protein Kinases Modeling Molecular Mutant Strains Mice Nature Output Pathway interactions Periodicity Phase Phosphorylation Photic Stimulation Physiological Physiological Processes Physiology Play Population Process Property Regulation Role Scaffolding Protein Series Shapes Signal Pathway Signal Transduction Stimulus System Testing Time Transgenic Mice Transgenic Organisms Work base biochemical tools cell type circadian circadian pacemaker circadian regulation design innovation insight light entrainment light gated mutant neural circuit novel programs response suprachiasmatic nucleus virtual

项目摘要

Project Summary/Abstract Virtually every aspect of human physiology and behavior is modulated by an inherent 24 hour (circadian) timing process. At the center of this clock timing system is the suprachiasmatic nucleus (SCN) of the hypothalamus. A key feature of the SCN clock is the tight, time-of-day, dependent regulation of the MAPK (p44/42 mitogen-activated protein kinase) pathway. Two examples of this phenomenon are the daily oscillations in the activation state of the MAPK pathway, and the clock-gated regulation of the photic responsiveness of the pathway. Importantly, the clock-generated, temporally-delimited, regulation of MAPK signaling appears to play a central role in SCN timing and entrainment. Further, the daily gating of MAPK signaling may be an underlying design principal of all oscillator populations, and as such, MAPK rhythms could have profound and far-reaching effects on a range of physiological processes. Given these implications, it is surprising that we still know relatively little about the cellular mechanisms and synaptic circuits that confer circadian control over MAPK activity. Here, we hypothesize that the circadian regulation of MAPK signaling is an inherent (cell autonomous) feature of SCN cellular oscillators and that this MAPK rhythm is a key mechanistic building-block by which the circadian clock modulates both basic and complex physiological states. To test this hypothesis, we propose the following set of experimental goals. In Aim 1, we will identify the cellular and network properties of the SCN that give rise to the rhythmic regulation of the MAPK pathway. To this end, we will, A) Determine whether MAPK rhythms are cell autonomous or whether they result from an intercellular SCN network, and B) Determine the intracellular signaling events that generate MAPK activity rhythms. In Aim 2 we propose to characterize the molecular, cellular and systems-based mechanisms by which the SCN clock gates light-evoked MAPK pathway activation. To address this largely unexplored phenomenon, we will, A) determine when and how the molecular gate opens, and B), test whether the cytoplasmic ERK scaffold protein PEA-15 serves as the principal circadian gate on MAPK signaling. Of note, we recently identified PEA-15 as a modulator of MAPK signaling in the SCN, and its capacity to dynamically regulate ERK signaling makes it an attractive candidate for the gating of MAPK signaling. In Aim 3 we propose to employ a selective targeting approach to transgenically disrupt MAPK signaling within the SCN core and shell regions to address the roles of MAPK signaling in A) the generation of circadian rhythms, and B) the entrainment of the circadian clock. Further, conditional PEA-15 KO and point mutant PEA-15 transgenic mouse lines will be used to test a model in which PEA-15 phosphorylation leads to rapid ERK dissociation, which we posit to be a key step in the initiation of light-evoked phase-shifting. Together, these data will provide fundamental new insights into the relationship between MAPK signaling and the circadian clock, and point to potential ways in which the dysregulation of clock-gated MAPK signaling could contribute to disorders of the CNS.

项目概要/摘要事实上，人类生理和行为的每个方面都受到固有的 24 小时（昼夜节律）的调节计时过程。该时钟计时系统的中心是视交叉上核（SCN）下丘脑。 SCN 时钟的一个关键特征是 MAPK 的严格、时间相关的调节（p44/42 丝裂原激活蛋白激酶）途径。这种现象的两个例子是日常 MAPK 通路激活状态的振荡，以及光的时钟门控调节通路的响应性。重要的是，MAPK 的时钟生成、时间分隔调节信号传导似乎在 SCN 计时和夹带中发挥着核心作用。此外，MAPK 的每日门控信号传导可能是所有振荡器群体的基本设计原则，因此，MAPK 节律可能对一系列生理过程产生深远的影响。鉴于这些影响，令人惊讶的是，我们对细胞机制和突触回路仍然知之甚少。赋予对 MAPK 活性的昼夜节律控制。在这里，我们假设 MAPK 的昼夜节律调节信号传导是 SCN 细胞振荡器的固有（细胞自主）特征，而 MAPK 节律是关键生物钟调节基本和复杂生理状态的机械构件。测试根据这个假设，我们提出以下一组实验目标。在目标 1 中，我们将识别细胞和 SCN 的网络特性引起 MAPK 通路的节律性调节。为此，我们将，A) 确定 MAPK 节律是否是细胞自主的，或者它们是否是由细胞间 SCN 网络，以及 B) 确定产生 MAPK 活性的细胞内信号传导事件节奏。在目标 2 中，我们建议描述分子、细胞和基于系统的机制，通过这些机制 SCN 时钟控制光诱发的 MAPK 通路激活。为了解决这个很大程度上未被探索的现象，我们将，A) 确定分子门何时以及如何打开，B) 测试细胞质 ERK 是否支架蛋白 PEA-15 是 MAPK 信号传导的主要昼夜节律门。值得注意的是，我们最近确定 PEA-15 是 SCN 中 MAPK 信号传导的调节剂，及其动态调节 ERK 的能力信号传导使其成为 MAPK 信号传导门控的有吸引力的候选者。在目标 3 中，我们建议采用选择性靶向方法以转基因方式破坏 SCN 核心和壳区域内的 MAPK 信号传导解决 MAPK 信号在 A) 昼夜节律的产生和 B) 夹带中的作用生物钟。此外，条件性 PEA-15 KO 和点突变 PEA-15 转基因小鼠系将被用于测试 PEA-15 磷酸化导致 ERK 快速解离的模型，我们认为这是一个光诱发相移启动的关键步骤。这些数据共同将提供根本性的新信息深入了解 MAPK 信号传导与生物钟之间的关系，并指出潜在的方法时钟门控 MAPK 信号传导失调可能导致中枢神经系统疾病。