R21: Entrainment of Peripheral Circadian Rhythms

R21：周围昼夜节律的牵引

• 批准号: 7176583
• 负责人: ERIC L BITTMAN
• 金额: $ 17.9万
• 依托单位: UNIVERSITY OF MASSACHUSETTS AMHERST
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-06 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7176583
• 关键词: Acetylcholine; Address; Adopted; Behavior; Behavioral; Biological Assay; Cells; Circadian Rhythms; Collection; Condition; Cues; Daily; Data; Disease; Endocrine; Epinephrine; Feedback; Funding; Genes; Glucagon; Glucocorticoids; Glucose; Health; Hepatic; Hormones; Hypothalamic structure; Insulin; Liver; Luciferases; Maps; Metabolic; Monitor; Mus; Neurotransmitters; Organ; Organ Culture Techniques; Pacemakers; Peripheral; Phase; Phase response curves; Physiologic pulse; Physiological; Production; Pulse taking; Range; Reporter; Research; Role; Running; Signal Transduction; Slice; Stimulus; System; Testing; Time; Tissues; Transgenic Mice; Transgenic Organisms; Very low density lipoprotein cholesterol; Work; circadian pacemaker; design; in vivo; innovation; liver function; novel; novel strategies; relating to nervous system; research study; suprachiasmatic nucleus; tool

DESCRIPTION (provided by applicant): Endogenous daily (circadian) rhythms govern many behavioral and physiological functions. A master pacemaker in the suprachiasmatic nucleus of the hypothalamus (SCN) controls these oscillations, but the transcriptional-translational feedback loops that generate them are distributed in cells throughout the body. These peripheral circadian oscillations persist for many cycles, if not indefinitely, in isolated organs after they are placed in culture. The SCN generates neural and endocrine signals in order to regulate circadian oscillations in peripheral tissues, but the way in which these signals act as entraining cues (zeitgebers) and the determinants of the phase taken by peripheral oscillators to the master pacemaker are poorly understood. Although powerful tools are available in the form of transgenic mice, novel approaches are required to determine the behavior, the physiological role, and the importance of the peripheral oscillators. The experiments described in this R21 application will utilize a mouse luciferase reporter construct in order to establish whether the SCN entrains hepatic oscillations, and to determine which specific signals serve as zeitgebers. The roles of the neurotransmitters epinephrine and acetylcholine, as well as hormones including glucocorticoids, insulin and glucagon, will be examined. The influence of fluctuations in glucose concentration will also be tested. A novel-flow through system will be used in which physiological signals (hormones or neurotransmitters) are added to organ culture chambers containing replicate sections of liver taken from transgenic Per2::luc mice. The ability of these signals to regulate period and phase will be established by luminometry, and we will determine whether the criteria of entrainment are met. For the first time for a peripheral oscillator, the range of entrainment will be examined and phase response curves wil be constructed. The health relevance of circadian organization will be evaluated as the impact of entrainment of the hepatic clock to various periods upon secretion of VLDL-cholesterol is determined through assay of the perifusion effluent. Once this luminometry system is established, it may be used to analyze not only entrainment of other hepatic circadian rhythms, but also the clock-like behavior of other organs. These studies will provide important new tools for analysis of the multi-oscillator system that governs normal physiological function and whose malfunction may contribute to disease.

描述（由申请人提供）：内源性日常（昼夜节律）节律控制着许多行为和生理功能。下丘脑视交叉上核 (SCN) 中的主起搏器控制这些振荡，但产生这些振荡的转录翻译反馈环路分布在全身的细胞中。在将离体器官置于培养物中后，这些外周昼夜节律振荡即使不是无限期地持续多个周期。 SCN 产生神经和内分泌信号以调节外周组织中的昼夜节律振荡，但这些信号作为夹带线索（时间）的方式以及外周振荡器对主起搏器采取的相位的决定因素知之甚少。尽管转基因小鼠可以提供强大的工具，但仍需要新的方法来确定外周振荡器的行为、生理作用和重要性。该 R21 应用中描述的实验将利用小鼠荧光素酶报告基因构建体来确定 SCN 是否夹带肝振荡，并确定哪些特定信号充当时间信号。将检查神经递质肾上腺素和乙酰胆碱以及糖皮质激素、胰岛素和胰高血糖素等激素的作用。还将测试葡萄糖浓度波动的影响。将使用一种新颖的流通系统，其中将生理信号（激素或神经递质）添加到含有取自转基因 Per2::luc 小鼠的肝脏复制切片的器官培养室中。这些信号调节周期和相位的能力将通过发光测定法确定，我们将确定是否满足夹带标准。对于外围振荡器，将首次检查夹带范围并构建相位响应曲线。将评估昼夜节律组织的健康相关性，因为通过测定灌注流出物来确定肝脏时钟对不同时期对 VLDL-胆固醇分泌的影响。一旦建立了这种发光测定系统，它不仅可以用于分析其他肝脏昼夜节律的夹带，还可以用于分析其他器官的类似时钟的行为。这些研究将为分析控制正常生理功能及其故障可能导致疾病的多振荡器系统提供重要的新工具。