Circadian SCN-Liver Axis in the Neuroendocrine Response to Calorie Restriction

昼夜节律 SCN-肝轴对热量限制的神经内分泌反应

• 批准号: 10585791
• 负责人: Joseph Bass
• 金额: $ 52.84万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2027-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10585791
• 关键词: ARNTL gene; Ablation; Acetylation; Behavioral; Bioenergetics; Body Temperature; Brain; CRISPR/Cas technology; Caloric Restriction; Cell Respiration; Cells; Communication; Darkness; Deacetylase; Deacetylation; Diet; Disinhibition; Epigenetic Process; Exhibits; Fasting; Genetic; Genetic Transcription; Goals; Health; Health Benefit; Hepatic; Homeostasis; Hypothalamic structure; Knock-in Mouse; Lactobacillus brevis; Light; Link; Liver; Maintenance; Mammals; Medial Dorsal Nucleus; Metabolic; Metabolic Pathway; Metabolism; Mitochondria; Molecular; Mus; Mutant Strains Mice; NADH; NADH oxidase; Neurons; Neurosecretory Systems; Nicotinamide adenine dinucleotide; Nutrient; Nutrient availability; Output; Oxidation-Reduction; Pacemakers; Pathway interactions; Periodicity; Peripheral; Physiological Adaptation; Post-Translational Protein Processing; Protocols documentation; Publishing; Reaction; Resistance; Respiration; Role; SIRT1 gene; Signal Transduction; Sleep; Sleep Wake Cycle; System; Testing; Thermogenesis; Tissues; Water; circadian; circadian pacemaker; detection of nutrient; feeding; gain of function; genetic approach; genetic manipulation; improved; innovation; loss of function; mimetics; neural circuit; programs; response; sleep regulation; suprachiasmatic nucleus; tool

In mammals, the hypothalamic pacemaker clock synchronizes peripheral tissue clocks to temporally partition oxidative and reductive metabolic pathways to align fuel utilization with nutrient availability. Yet how the circadian clock in brain and peripheral tissues integrates nutrient state with transcription to promote energy conservation and metabolic homeostasis during sleep and in nutrient scarce conditions remains obscure. An exciting clue as to how nutrient signals control circadian transcription emerged from the discovery in our group and others that nicotinamide adenine dinucleotide (NAD+) and the NAD+-dependent deacetylase SIRT1 regulate circadian behavioral and mitochondrial rhythms through posttranslational modification of the core clock repressor PER2, indicating that NAD+-SIRT1 controls clock cycles within both neurons and peripheral cells. Interconversion of NAD+ with its reduced form NADH during redox reactions is dependent upon nutrient state. In new results published after our first submission, we show that NADH accumulation in liver during healthful calorie restriction inhibits SIRT1 and reduces daytime body temperature and oxidative metabolism. Surprisingly, reducing NADH levels through hepatic transduction of the water-forming NADH oxidase Lactobacillus brevis (LbNOX) disinhibits SIRT1 and augments oxidative cycles of metabolism and transcription. Further, our newly-generated PER2K680Q acetyl-mimetic knockin mice, which are resistant to SIRT1-induced deacetylation, exhibit profound period lengthening, while clock ablation in the suprachiasmatic nucleus (SCN) abrogates rhythmic feeding and thermogenesis. We are now poised with innovative genetic tools and circadian protocols to dissect how the circadian clock promotes energy constancy during sleep and in adaptation to calorie restriction at the level of the liver (Aim 1) and hypothalamic pacemaker neurons (Aim 2). Aim 1 will specifically test the hypothesis that nutrient sensing by the clock involves NAD(H)-SIRT1 signaling. We propose to dissect the role of redox state in clock function and metabolism during sleep and calorie restriction by genetically manipulating NAD(H) levels using LbNox in combination with hepatic clock ablation or PER2K680Q acetyl-mimetic knockin mice. Aim 2 will examine the role of hypothalamic pacemaker neuron subtypes in synchronizing thermogenesis, feeding, and metabolic rhythms with sleep and in the adaptive response to calorie restriction by utilizing an innovative combination of CRISPR-Cas9 clock ablation, loss and gain of function studies, and projection-based chemogenetic manipulation of pacemaker neurons. Collectively, our proposed studies will elucidate circadian mechanisms involved in maintenance of energy constancy across the sleep-wake cycle and how clock adaptations contribute to health benefits of hypocaloric diet.

在哺乳动物中，下丘脑起搏器时钟同步外周组织时钟以进行时间分区 氧化和还原代谢途径，使燃料利用率与营养物质可用性保持一致。然而昼夜节律如何 大脑和周围组织中的时钟将营养状态与转录结合起来，以促进能量保存 睡眠期间和营养匮乏条件下的代谢稳态仍然不清楚。一个令人兴奋的线索 我们小组和其他人的发现揭示了营养信号如何控制昼夜节律转录 烟酰胺腺嘌呤二核苷酸 (NAD+) 和 NAD+ 依赖性脱乙酰酶 SIRT1 调节昼夜节律 通过核心时钟抑制子 PER2 的翻译后修饰来调节行为和线粒体节律， 表明 NAD+-SIRT1 控制神经元和外周细胞内的时钟周期。相互转换 NAD+ 及其还原形式 NADH 在氧化还原反应过程中取决于营养状态。在新结果中 在我们第一次提交后发表的文章中，我们表明健康热量限制期间肝脏中 NADH 的积累 抑制 SIRT1 并降低白天体温和氧化代谢。令人惊讶的是，减少 NADH 通过肝脏转导形成水的 NADH 氧化酶来抑制短乳杆菌 (LbNOX) 的水平 SIRT1 并增强代谢和转录的氧化循环。此外，我们新生成的 PER2K680Q 乙酰模拟敲入小鼠对 SIRT1 诱导的脱乙酰化具有抵抗力，表现出深刻的周期 延长，同时视交叉上核（SCN）的时钟消融消除了节律性进食和 生热作用。我们现在准备使用创新的遗传工具和昼夜节律协议来剖析如何 生物钟促进睡眠期间的能量恒定以及适应卡路里限制水平 肝脏（目标 1）和下丘脑起搏神经元（目标 2）。目标 1 将专门检验以下假设：营养素 时钟传感涉及 NAD(H)-SIRT1 信号传输。我们建议剖析氧化还原态在时钟中的作用 通过基因操纵 NAD(H) 水平来限制睡眠期间的功能和代谢以及卡路里限制 LbNox 与肝时钟消融或 PER2K680Q 乙酰模拟敲入小鼠组合。目标 2 将检查 下丘脑起搏器神经元亚型在同步生热、进食和代谢中的作用 通过利用创新的组合来调节睡眠节律和对卡路里限制的适应性反应 CRISPR-Cas9 时钟消融、功能丧失和获得研究以及基于预测的化学遗传学操作 起搏器神经元。总的来说，我们提出的研究将阐明涉及的昼夜节律机制 维持整个睡眠-觉醒周期的能量恒定以及生物钟适应如何促进健康 低热量饮食的好处。