Lipid droplets and the compartmentalization of subcellular metabolism

脂滴和亚细胞代谢的区室化

• 批准号: 10589330
• 负责人: Douglas G Mashek
• 金额: $ 34.49万
• 依托单位: UNIVERSITY OF MINNESOTA
• 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/10589330
• 关键词: Affect; Aging; Architecture; Area; Biochemical; Biochemical Pathway; Bioenergetics; Biogenesis; Cardiovascular Diseases; Cell physiology; Cells; Cellular biology; Characteristics; Cirrhosis; Coupling; Data; Development; Disease; Endoplasmic Reticulum; Energy Metabolism; Etiology; Fasting; Fatty Acids; Functional disorder; Glean; Health; Hepatic; High Fat Diet; Human; Isotopes; Laboratories; Link; Lipids; Liver; Liver diseases; Malignant Neoplasms; Membrane; Membrane Lipids; Metabolic; Metabolic Diseases; Metabolic Pathway; Metabolism; Mitochondria; Mus; Non-Insulin-Dependent Diabetes Mellitus; Nutritional; Organelles; Oxidative Phosphorylation; Pathway interactions; Physiological; Play; Proteins; Proteome; Proteomics; Publishing; Research; Risk; Role; Route; Signal Transduction; Testing; Therapeutic; Time; Work; cell type; comorbidity; fatty acid oxidation; feeding; imaging approach; innovation; lipid metabolism; liver biopsy; mitochondrial membrane; mitochondrial metabolism; mouse model; non-alcoholic fatty liver disease; novel; oxidation; protein metabolism; sensor; superresolution imaging; superresolution microscopy; trafficking; transcriptome sequencing

Lipid droplets (LDs), the organelles responsible for lipid storage and the largest energy reserve in most cell types, are the defining characteristic and etiological factor in the development of non-alcoholic fatty liver disease (NAFLD). Moreover, LDs are recognized to play central roles in coupling NAFLD to more systemic comorbidities such as Type 2 Diabetes and cardiovascular disease among others. LDs interact with numerous organelles, especially ER and mitochondria, which are thought to coordinate de novo LD biogenesis and fatty acid (FA) transfer/oxidation, respectively. However, published work from our laboratory and others have questioned the established dogma that direct transfer of FAs from LDs to mitochondria is the primary route of their oxidation during fasting. Using a multifaceted approach involving organelle proteomics, isotope tracing, and numerous super resolution microscopy approaches, we show for the first time that in the liver, the proteomes and metabolism of mitochondria attached to LDs (peridroplet mitochondria, PDM) support lipid anabolic pathways, whereas mitochondria unattached to LDs (cytosolic mitochondria, CM) a geared for enhanced FA oxidation and OXPHOS. Moreover, our data point to an important role for mitochondrial-associated membranes (MAMs), an ER domain that tightly interacts with mitochondria, as a key component in regulating LD-mitochondria interactions and dynamics. Collectively, these data suggest that interactions with LDs profoundly affect organelle dynamics and function. Based upon these data, the objective of this application is to define how LD interactions affect lipid metabolism and sensing to coordinate ER and mitochondrial function under physiological and pathophysiological conditions. We hypothesize that interactions of LDs with ER and mitochondria are critical modulators of MAM lipid sensing and mitochondrial function that govern hepatic lipid and energy metabolism. To test this hypothesis, we propose the following three specific aims: Aim 1 - To comprehensively define LD- mitochondria interactions and their impact on FA trafficking; Aim 2 - To determine the mechanisms through which subpopulations of MAM differentially impact mitochondrial bioenergetics and lipid metabolism; and Aim 3 - To determine how NAFLD impacts LD/MAM/mitochondria dynamics in NAFLD. To complete these aims, we will employ a wide range of advanced super resolution imaging approaches, proteomics and RNA sequencing, isotope tracing, and other cell biology and biochemical approaches in cells, mouse models and human liver biopsies. Upon completion of these studies, we will expect that we will have revealed novel mechanisms through which LDs can alter cellular function/dysfunction that underlie NAFLD etiology. We anticipate that this work will open new areas of research into intracellular signaling dynamics, which will advance therapeutic approaches targeting NAFLD and related comorbidities.

脂滴(LDs)，负责储存脂质的细胞器，是大多数细胞类型中最大的能量储备， 是非酒精性脂肪性肝病发展的明确特征和病因 (NAFLD)。此外，LDS被认为在NAFLD与更多系统性合并症的结合中起着核心作用。 如2型糖尿病和心血管疾病等。LDS与许多细胞器相互作用， 特别是内质网和线粒体，它们被认为协调LD的新生物发生和脂肪酸(FA)。 分别为转移/氧化。然而，我们实验室和其他实验室发表的研究成果质疑 公认的教条是FA从LDS直接转移到线粒体是其氧化的主要途径 在禁食期间。使用多方面的方法，涉及细胞器蛋白质组学、同位素示踪和许多 超分辨率显微镜的方法，我们第一次显示，在肝脏中，蛋白质组和 附着在LDS(Peridroplet线粒体，PDM)上的线粒体的代谢支持脂质合成途径， 而线粒体不附着于LDS(细胞质线粒体，CM)，则适合增强FA氧化和 氧磷酸盐。此外，我们的数据指出了线粒体相关膜(MAM)的重要作用，以及 与线粒体紧密相互作用的ER结构域，作为调节LD-线粒体的关键成分 相互作用和动态。总而言之，这些数据表明与LDS的相互作用深刻地影响细胞器 动力和功能。基于这些数据，本应用程序的目标是定义LD如何交互 生理和心理状态下影响脂质代谢和感觉协调内质网和线粒体功能 病理生理条件。我们假设LDS与内质网和线粒体的相互作用是至关重要的 调节肝脏脂肪和能量代谢的MAM脂质感知和线粒体功能的调节剂。 为了验证这一假设，我们提出了以下三个具体目标：目标1-全面定义LD- 线粒体相互作用及其对FA贩运的影响；目标2--确定 MAM的亚群对线粒体生物能量学和脂质代谢有不同的影响；目标3-到 确定NAFLD如何影响NAFLD的LD/MAM/线粒体动力学。为了实现这些目标，我们将 采用了一系列先进的超分辨率成像方法、蛋白质组学和RNA测序， 同位素示踪，以及细胞、小鼠模型和人类肝脏中的其他细胞生物学和生化方法 活组织检查。这些研究完成后，我们预计将通过以下途径揭示新的机制 哪些LDS可以改变NAFLD病因所依据的细胞功能/功能障碍。我们预计这项工作将 开辟了细胞内信号动力学研究的新领域，这将推动治疗方法的发展 以非酒精性脂肪肝及相关并发症为目标。