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.

摘要 烟酰胺腺嘌呤二核苷酸（NAD+）是一种辅因子和信号分子，可调节细胞分裂的关键过程。 轴突变性的DNA修复。NAD+水平随着线粒体功能障碍、衰老和不同年龄段的人而下降。 相关的病理。此外，研究一再表明，增加NAD+水平有利于细胞增殖， 和有机体的健康寿命。多个细胞区室包含NAD+合成和NAD+消耗信号传导 蛋白质，但很少有人知道的机制，其中NAD+浓度在每个细胞器是适当的 调节代谢和信号需求。线粒体携带高达70%的细胞NAD+，NAD+作为一种蛋白质， 线粒体呼吸中的电子载体，并通过线粒体sirtuins作为信号分子。然而，在这方面， 目前尚不清楚线粒体NAD+库是如何建立和维持的，也不知道它是如何促进细胞凋亡的。 代谢控制利用基因共必要性分析，我们最近发现了一个线粒体转运蛋白，SLC 25 A51， 线粒体摄取NAD+所必需的。我们假设SLC 25 A51是细胞NAD+的主要因素 它是一种细胞间区室化，在代谢稳态和细胞对压力的反应中起着关键作用。一个主要的长期- 我们研究计划的长期目标是了解细胞如何调节其线粒体NAD+库和NAD+ 在健康和疾病中控制代谢和信号传导的区室化。未来五年，我们将重点 本建议概述了三个方面：1）了解生物化学机制和驱动力， 线粒体NAD+转运通过表征SLC 25 A51在无细胞蛋白脂质体转运中的活性 2）通过鉴定信号传导途径，确定线粒体NAD+转运是如何调节的， 转录因子调控SLC 25 A51的表达，并通过阐明蛋白质是如何被翻转， 从线粒体内膜移除;和3）描绘细胞质-线粒体NAD+ 使用SLC 25 A51功能丧失小鼠，区室化有助于肝脏中的代谢调节 模型我们的研究结果将为细胞NAD+的机制提供重要的见解 区室化和识别与人类疾病相关的新的代谢调节模式。本研究 该计划与我们实验室的总体目标是一致的，以了解代谢的机制， 区室化，特别是线粒体转运蛋白的作用，在调节线粒体功能， 代谢需求和细胞状态，以及对压力的反应。