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+) 是一种辅助因子和信号分子，可调节关键过程 DNA 修复轴突变性随着线粒体功能障碍、衰老和不同年龄阶段的发生而下降。 此外，研究多次表明 NAD+ 水平的增加对细胞有益。 多个细胞区室包含 NAD+ 合成和 NAD+ 消耗信号。 蛋白质，但对于每个细胞器中 NAD+ 浓度适当的机制知之甚少 线粒体含有高达 70% 的细胞 NAD+，而 NAD+ 则充当细胞中的 NAD+。 线粒体呼吸中的电子载体，并作为线粒体沉默调节蛋白的信号分子。 目前尚不清楚线粒体 NAD+ 池是如何建立和维持的，也不知道它如何促进细胞 通过基因共必需性分析，我们最近鉴定了一种线粒体转运蛋白 SLC25A51， 我们认为 SLC25A51 是细胞 NAD+ 的主要因子。 区室化是代谢稳态和细胞对压力反应的关键因素。 我们研究项目的长期目标是了解细胞如何调节线粒体 NAD+ 库和 NAD+ 未来五年，我们将重点关注控制健康和疾病中的新陈代谢和信号传导。 该提案概述的三个领域：1）了解生化机制和驱动力 通过表征无细胞蛋白脂质体转运中 SLC25A51 的活性来研究线粒体 NAD+ 转运 2) 通过识别信号通路来确定线粒体 NAD+ 转运的调节方式 调节 SLC25A51 表达的转录因子，并阐明蛋白质如何在或 从线粒体内膜去除；3) 描述胞质线粒体 NAD+ 的作用 使用 SLC25A51 功能丧失小鼠进行区室化有助于肝脏代谢调节 我们的研究结果将为细胞 NAD+ 的机制提供重要的见解。 这项研究划分并确定与人类疾病相关的代谢调节的新模式。 该计划与我们实验室了解代谢机制的总体目标一致 区室化，特别是线粒体转运蛋白在调节线粒体功能中的作用 代谢需求和细胞状态，以及对压力的反应。