MAPK signaling: gates, oscillators and circadian timing

MAPK 信号：门、振荡器和昼夜节律计时

• 批准号: 9981221
• 负责人: KARI RENE HOYT
• 金额: $ 46.69万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 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/9981221
• 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

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.

项目摘要/摘要 实际上，人类生理和行为的各个方面都由固有​​的24小时（昼夜节律）调节 定时过程。在这个时钟正时系统的中心是核上核（SCN） 下丘脑。 SCN时钟的一个关键特征是MAPK的紧密，时间依赖的调节 （P44/42丝裂原激活的蛋白激酶）途径。这种现象的两个例子是每日 MAPK途径的激活状态的振荡和光学的时钟门控调节 路径的响应能力。重要的是，时钟生成的，暂时性的，MAPK的调节 信号传导似乎在SCN时机和夹带中起着核心作用。此外，MAPK的每日门控 信号传导可能是所有振荡器种群的基本设计主管，因此MAPK节奏 可能会对一系列生理过程产生深远和深远的影响。鉴于这些含义 令人惊讶的是，我们仍然对细胞机制和突触电路的了解相对较少 赋予昼夜节律对MAPK活动的控制。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（单元自主）特征，并且该MAPK节奏是关键 昼夜节律调节基本和复杂生理状态的机械建筑块。测试 这个假设，我们提出了以下一组实验目标。在AIM 1中，我们将确定细胞和 SCN的网络属性引起了MAPK途径的节奏调节。为此， 我们将，a）确定MAPK节奏是否是细胞自主或它们是由 细胞间SCN网络和b）确定生成MAPK活动的细胞内信号传导事件 节奏。在AIM 2中，我们建议表征分子，细胞和基于系统的机制 SCN时钟门诱发的MAPK途径激活。为了解决这一很大程度上未开发的现象， 我们将a）确定分子栅极何时以及如何打开，b）测试胞质ERK是否是否打开 脚手架蛋白质PEA-15是MAPK信号传导上的主要昼夜节门。值得注意的是，我们最近 将PEA-15鉴定为SCN中MAPK信号的调节剂，并且其动态调节ERK的能力 信号传导使其成为MAPK信号传输门控的有吸引力的候选者。在AIM 3中，我们建议采用 选择性的靶向方法，用于跨基因中断SCN核心和外壳区域内的MAPK信号传导 解决MAPK信号在a）产生昼夜节律的作用，b） 昼夜节律。此外，有条件的PEA-15 KO和点突变体Pea-15转基因小鼠系将是 用于测试PEA-15磷酸化导致快速ERK解离的模型，我们认为这是一个 启动光相变的关键步骤。这些数据将共同提供基本的新 了解MAPK信号传导与昼夜节律之间的关系，并指出潜在的方式 时钟门控MAPK信号的失调可能导致CNS的疾病。