Dissecting metabolic control by cytosolic-mitochondrial NAD compartmentalization

通过胞浆-线粒体 NAD 区室化剖析代谢控制

• 批准号: 10714342
• 负责人: Nora Kory
• 金额: $ 37.2万
• 依托单位: HARVARD SCHOOL OF PUBLIC HEALTH
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-05 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10714342
• 关键词: Aging; Area; Biochemical; Biological Assay; Cells; Consumption; DNA Repair; Diabetes Mellitus; Disease; Electrons; Genes; Goals; Health; Homeostasis; Human; Inner mitochondrial membrane; Laboratories; Link; Liver; Malignant Neoplasms; Metabolic; Metabolic Control; Metabolism; Mitochondria; Neurodegenerative Disorders; Nicotinamide adenine dinucleotide; Organelles; Oxidation-Reduction; Pathology; Physiology; Process; Proteins; Regulation; Research; Respiration; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Signaling Protein; Sirtuins; Stress; age related; axonal degeneration; cofactor; driving force; healthspan; human disease; insight; loss of function; mitochondrial dysfunction; mouse model; programs; proteoliposomes; response; transcription factor; uptake

Abstract Nicotinamide adenine dinucleotide (NAD+) is a cofactor and signaling molecule that regulates critical processes from DNA repair to axon degeneration. NAD+ levels decline with mitochondrial dysfunction, in aging, and in various age- related pathologies. Moreover, studies have repeatedly shown that increased NAD+ levels are beneficial for cellular and organismal healthspan. Multiple cellular compartments contain NAD+-synthesis and NAD+-consuming signaling proteins, but little is known about the mechanisms by which NAD+ concentrations in each organelle are appropriately tuned to metabolic and signaling demands. Mitochondria harbor up to 70% of cellular NAD+, and NAD+ acts as an electron carrier in mitochondrial respiration and as a signaling molecule through the mitochondrial sirtuins. However, it is not known how the mitochondrial NAD+ pool is established and maintained or how it contributes to cellular metabolic control. Using gene co-essentiality analysis, we recently identified a mitochondrial transporter, SLC25A51, required for the uptake of NAD+ into mitochondria. We hypothesize that SLC25A51 is a major factor in cellular NAD+ compartmentalization and a critical player in metabolic homeostasis and a cell’s response to stress. A major long- term goal of our research program is to understand how cells regulate their mitochondrial NAD+ pool and NAD+ compartmentalization to control metabolism and signaling in health and disease. In the next five years, we will focus on three areas outlined in this proposal: 1) understanding the biochemical mechanism and driving forces of mitochondrial NAD+ transport by characterizing the activity of SLC25A51 in cell-free proteoliposome transport assays; 2) determining how mitochondrial NAD+ transport is regulated, by identifying the signaling pathway and transcription factors that regulate SLC25A51 expression and by elucidating how the protein is turned over in or removed from the inner mitochondrial membrane; and 3) delineating how cytosolic-mitochondrial NAD+ compartmentalization contributes to metabolic regulation in the liver using SLC25A51 loss-of-function mouse models. The results of our studies will provide important insights into the mechanisms of cellular NAD+ compartmentalization and identify new modes of metabolic regulation relevant for human disease. This research program is aligned with our laboratory’s overall goals to understand the mechanisms of metabolic compartmentalization, and specifically the role of mitochondrial transporters, in adjusting mitochondrial function to metabolic demands and cell state, and responding to stress.

抽象的 烟酰胺腺嘌呤二核苷酸（NAD+）是一种辅因子和信号分子，可调节来自关键过程 DNA修复到轴突变性。 NAD+水平下降，线粒体功能障碍，衰老和各个年龄段 相关病理。此外，研究反复表明，NAD+水平升高对细胞有益 和有机健康范围。多个蜂窝室包含nAD+ - 联合和NAD+震动信号传导 蛋白质，但对每个细胞器中NAD+浓度的机制知之甚少 调整了代谢和信号的需求。线粒体港口高达70％的细胞NAD+，而NAD+充当 线粒体呼吸中的电子载体和通过线粒体sirtuins作为信号分子。然而， 尚不清楚如何建立和维护线粒体NAD+池或如何贡献细胞 代谢控制。使用基因共同性分析，我们最近确定了线粒体转运蛋白SLC25A51， 摄取NAD+进入线粒体所必需的。我们假设SLC25A51是细胞NAD+的主要因素 隔室化和代谢稳态的关键参与者以及细胞对压力的反应。主要长期 我们的研究计划的术语目标是了解细胞如何调节其线粒体NAD+池和NAD+ 控制健康和疾病中的代谢和信号传导的分隔。在接下来的五年中，我们将集中精力 在此提案中概述的三个领域：1）了解 线粒体NAD+传输通过表征SLC25A51在无细胞蛋白质体转运中的活性 测定； 2）通过识别信号通路和 调节SLC25A51表达的转录因子，并通过阐明如何将蛋白质翻转或 从内部线粒体膜中取出； 3）描述细胞质量的NAD+如何 隔室化使用SLC25A51损失小鼠有助于肝脏中的代谢调节 型号。我们的研究结果将为细胞NAD+的机制提供重要的见解 分隔并确定与人类疾病相关的代谢调节的新模式。这项研究 计划与我们实验室的总体目标保持一致，以了解代谢机制 隔室化，特别是线粒体转运蛋白的作用，在将线粒体功能调整为 代谢需求和细胞状态，并应对压力。