Unraveling the molecular connections that link circadian rhythms and lipid metabolism

项目摘要 生物钟的失调和破坏导致代谢和生理功能障碍。时钟调节 新陈代谢，而代谢活动反馈影响昼夜节律，这种相互作用之间的时钟 新陈代谢协调生理机能。然而，一个主要的知识差距是对 新陈代谢影响生物钟功能的机制。这项研究的目的是阐明 生物钟和脂质代谢通过相互作用和相互作用相互联系的机制 使用模式生物拟南芥的脂质介质和主要的时钟调节器之间的调节。的 所提出的研究的可行性得到最近发现的支持，即中心甘油脂代谢中间体， 磷脂酸（PA），直接结合到时钟转录因子LHY（晚伸长下胚轴）， PA代谢活动的操纵改变了时钟输出，时钟的中断扰乱了脂质的积累， 拟南芥。该假说认为PA-LHY相互作用作为细胞导管整合生物钟 与脂质代谢和介导脂质生产和生物体对不断变化的环境的反应。测试 假设，目标1将通过确定脂质结合特异性来表征PA与时钟调节因子的相互作用 与LHY的结合，参与PA结合的氨基酸残基，以及PA-LHY相互作用的细胞内位置， 亚细胞特异性PA生物传感器和质谱法。目标2将讨论PA代谢的改变是如何导致 生物钟和介导的压力反应，通过鉴定基因/酶负责生产PA种类， 更改时钟功能。通过量化细胞PA变化对生物钟相关基因表达的影响， 这些数据将用于模拟细胞PA变化如何导致昼夜节律和生物钟的改变 产出目标3将通过使用生物钟突变体来评估生物钟如何影响脂质代谢， 内部昼夜节律和外部环境之间的失调影响脂质代谢， 积累此外，脂质代谢中的时钟靶向基因将被鉴定并测试其在昼夜节律中的作用。 调节脂质积累。这项研究将揭示生物钟和生物钟的新的调节机制。 和脂质代谢，并将推进目前对这两种途径之间相互作用的理解。结果 与人类健康有关，因为PA是参与哺乳动物生物钟调节的脂质介质， 生物钟的基本分子机制在植物和人类之间是保守的。 因此，所提出的工作的影响是推进分子互连的基础知识 真核生物中脂质代谢和生物钟之间的联系，这些信息有可能成为未来的战略， 了解和减轻与生物钟中断相关的代谢和生理功能障碍。

PROJECT SUMMARY Misalignments and disruption of the circadian clock lead to metabolic and physiological dysfunctions. The clock regulates metabolism whereas metabolic activities feedback to influence circadian rhythms, and this interplay between the clock and metabolism coordinates physiology. However, one major knowledge gap is the limited understanding of the mechanism by which metabolism affects clock function. The goal of the proposed research is to elucidate the molecular mechanism by which the circadian clock and lipid metabolism are interconnected through the interaction and reciprocal regulation between lipid mediators and major clock regulators using the model organism Arabidopsis thaliana. The feasibility of the proposed research is supported by recent findings that the central glycerolipid metabolic intermediate, phosphatidic acid (PA), directly binds to the clock transcription factor LHY (LATE ELONGATED HYPOCOTYL), manipulations of PA-metabolizing activities alter clock outputs, and disruptions of the clock perturb lipid accumulation in Arabidopsis. The hypothesis is that the PA-LHY interaction functions as a cellular conduit to integrate the circadian clock with lipid metabolism and mediate lipid production and organismal responses to changing environments. To test the hypothesis, Aim 1 will characterize PA interaction with the clock regulators by determining the lipid binding specificity to LHY, the amino acid residues involved in PA binding, and the intracellular location of the PA-LHY interaction using subcellular-specific PA biosensors and mass spectrometry. Aim 2 will address how altered PA metabolism entrains the circadian clock and mediates stress responses by identifying genes/enzymes responsible for producing PA species that alter clock function. Through quantifying the effect of cellular PA changes on the expression of genes involved in clock regulation, these data will be used to model how cellular PA changes lead to alterations in circadian rhythms and clock outputs. Aim 3 will determine how the circadian clock affects lipid metabolism by using clock mutants to assess how misalignments between internal circadian rhythms and the external environment affect lipid metabolism and accumulation. In addition, clock-targeted genes in lipid metabolism will be identified and tested for roles in the circadian regulation of lipid accumulation. The proposed studies will reveal new regulatory mechanisms for both the circadian clock and lipid metabolism and will advance the current understanding of the interplay between these two pathways. The results are relevant to human health because PA is a lipid mediator involved in mammalian clock regulation and various pathological processes, and the basic molecular mechanism of the clock is conserved between plants and humans. Therefore, the impact of the proposed work is to advance foundational knowledge for the molecular interconnection between lipid metabolism and the clock in eukaryotes, and the information has the potential for future strategies for understanding and mitigating metabolic and physiological dysfunctions associated with clock disruptions.