The role of the peripheral liver circadian clock and diurnal gut microbial mediators in the regulation of hepatic gluconeogenesis

外周肝脏生物钟和昼夜肠道微生物介质在肝糖异生调节中的作用

• 批准号: 10228095
• 负责人: Katya Morgan Frazier
• 金额: $ 4.6万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-18 至 2022-09-17
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10228095
• 关键词: 16S ribosomal RNA sequencing; ARNTL gene; Address; Adult; Affect; Albumins; Animal Model; Animals; Aspirate substance; Back; Base Sequence; Bile Acids; Biological Assay; Body Composition; Circadian Dysregulation; Circadian Rhythms; Complex; Coupled; Coupling; Critical Thinking; Cues; Data; Deuterium Oxide; Development; Diet; Disease; Dual-Energy X-Ray Absorptiometry; Eating; Enterobacteria phage P1 Cre recombinase; Environment; Enzymes; Exhibits; Experimental Models; Fasting; Fatty acid glycerol esters; Feces; Feeding behaviors; Gene Expression Profile; Genes; Genetic Transcription; Germ-Free; Gluconeogenesis; Glucose; Gnotobiotic; Goals; Health; Hepatic; Hepatocyte; Hour; Human; Infusion procedures; Insulin; Integration Host Factors; Intestines; Knockout Mice; Knowledge; Lead; Light; Liver; LoxP-flanked allele; Maintenance; Measurement; Measures; Mediating; Mediator of activation protein; Metabolic; Metabolic syndrome; Metabolism; Metagenomics; Microbe; Modification; Molecular; Mus; Nature; Non-Insulin-Dependent Diabetes Mellitus; Organ; Outcome; Output; Pattern; Peripheral; Phenotype; Physiological; Physiology; Plasma; Process; Production; Pyruvate; Regulation; Research Personnel; Ribosomal RNA; Role; Sampling; Scanning; Sleep Wake Cycle; System; Technology; Testing; Therapeutic Intervention; Thinness; Time; Time-restricted feeding; Training; Transgenic Mice; Transgenic Organisms; Transplantation; Volatile Fatty Acids; Wild Type Mouse; Work; base; blood glucose regulation; career development; circadian; circadian pacemaker; energy balance; experimental study; germ free condition; glucose metabolism; glucose production; glucose tolerance; gut microbes; gut microbiome; gut microbiota; hepatic gluconeogenesis; in vivo; insight; knowledge base; meetings; metabolomics; metagenomic sequencing; microbial; microbial community; microbiota; mouse model; novel; skill acquisition; skills; symposium; therapeutically effective; transcription factor

PROJECT SUMMARY: Metabolic syndrome affects over 25% of adults in the US and is difficult to treat due to its multifactorial and complex nature. Glucose dysregulation, either excess or deficiency of glucose levels, is a hallmark of metabolic syndrome with both short- and long-term detrimental physiological effects. Hepatic gluconeogenesis, the endogenous production of glucose in the liver, is critical for maintenance of glucose homeostasis during periods of prolonged fasting. Although gluconeogenesis is influenced by a myriad of systems, strong evidence suggests that host circadian rhythms and cues provided by the gut microbiome significantly contribute to this process. Disruption of either system leads to aberrant hepatic gluconeogenesis, although few mechanistic insights provide an explanation for how these consequences arise and how the two systems are connected. Using novel experimental approaches, I will tease apart these relationships to define the specific mechanisms of action of the hepatic core circadian clock and gut microbiota in regulating glucose homeostasis. Thus, I will address the unmet need for targeted and effective therapeutic interventions for metabolic syndrome. My preliminary data show that targeted deletion of the hepatic core circadian clock gene Bmal1 leads to increased glucose clearance and reduced gluconeogenesis in Specific Pathogen Free (SPF) but not germ-free (GF) mice. This phenotypic difference can be restored by transplantation of a full microbial community into GF hepatic Bmal1 deficient mice, implying that gut microbes are necessary and sufficient for proper hepatic Bmal1 regulation of gluconeogenesis. Microbial 16S rRNA sequencing of stool serially collected over 48 hours reveals that mice lacking hepatic Bmal1 exhibit nearly twice the number of oscillating Clostridia taxa, suggesting changes in microbial community dynamics and function could feed back to alter host metabolism. These data led me to hypothesize that hepatic gluconeogenesis is driven by bidirectional interactions between the hepatic circadian clock and diurnal patterns of specific classes of gut microbes and metabolites. I will utilize both SPF and GF Bmal1-floxed Albumin-Cre transgenic mice, where Bmal1 is deleted only in hepatocytes. Two central aims are proposed: 1) Examine the central role of the liver clock in transducing gut microbial cues that regulate host hepatic GNG and glucose metabolism, and 2) Identify how known gut microbial products that have been shown to modulate liver clock function mediate clock-controlled hepatic GNG and systemic glucose regulation. I will apply in vivo experimental models, gnotobiotic technology, functional metagenomic analyses, and murine conventionalization experiments. This strategy will fill crucial gaps in knowledge relevant to the interactions between gut microbes and peripheral circadian clocks, as well as mechanisms governing how each system imposes unique influence on hepatic gluconeogenesis. These studies serve as an outstanding training vehicle for me to develop the experimental and critical thinking skills necessary to become a productive and independent researcher focused on the microbial basis of host metabolism.

项目概要： 代谢综合征影响美国超过25%的成年人，由于其多因素和多途径， 复杂的性质。葡萄糖调节异常，无论是过量或不足的葡萄糖水平，是一个标志性的代谢 综合征，具有短期和长期的有害生理影响。肝纤维化 肝脏中葡萄糖的内源性产生，对于维持月经期间的葡萄糖稳态至关重要。 长时间的禁食尽管生物的发生受到无数系统的影响，但强有力的证据表明， 宿主的昼夜节律和肠道微生物组提供的线索对这一过程有很大贡献。 任何一个系统的破坏都会导致异常的肝脏再生，尽管很少有机制性的见解提供 解释这些后果是如何产生的，以及这两个系统是如何连接的。使用新颖 实验方法，我将梳理除了这些关系，以确定具体的作用机制， 肝脏核心生物钟和肠道微生物群在调节葡萄糖稳态中的作用。因此，我将向 对代谢综合征的靶向和有效治疗干预的需求尚未得到满足。 我的初步数据显示，靶向删除肝脏核心生物钟基因Bmal 1， 在无特定病原体（SPF）但非无菌条件下，增加葡萄糖清除率并减少新生血管生成 (GF)小鼠这种表型差异可以通过将完整的微生物群落移植到GF中来恢复 肝Bmal 1缺陷小鼠，这意味着肠道微生物对于适当的肝Bmal 1是必要和足够的。 调节植物的生长发育。连续收集48小时的粪便的微生物16 S rRNA测序显示， 缺乏肝脏Bmal 1的小鼠表现出近两倍数量的振荡梭菌分类群，这表明 微生物群落的动态和功能可以反馈改变宿主的代谢。这些数据让我 假设肝纤维化的发生是由肝纤维化和肝纤维化之间的双向相互作用驱动的， 特定种类的肠道微生物和代谢物的昼夜节律钟和昼夜模式。我会利用两者 SPF和GF Bmal 1-floxed Albumin-Cre转基因小鼠，其中Bmal 1仅在肝细胞中缺失。两 提出的主要目的是：1）检查肝脏时钟在转导肠道微生物线索中的中心作用， 调节宿主肝脏GNG和葡萄糖代谢，以及2）确定已知的肠道微生物产物如何具有 已显示调节肝脏生物钟功能介导时钟控制的肝脏GNG和全身葡萄糖 调控我将应用体内实验模型，gnotobiotic技术，功能宏基因组分析， 和小鼠常规化实验。这一战略将填补与下列方面有关的知识方面的重大空白： 肠道微生物和外周生物钟之间的相互作用，以及控制每种生物钟的机制， 系统对肝硬化的发生具有独特的影响。这些研究作为一个优秀的培训， 我的工具，以发展必要的实验和批判性思维技能，成为一个富有成效的， 一位独立的研究人员专注于宿主代谢的微生物基础。