The role of NADPH production in regulating endoplasmic reticulum function and the progression of non-alcoholic steatohepatitis

NADPH产生在调节内质网功能和非酒精性脂肪性肝炎进展中的作用

• 批准号: 10386489
• 负责人: Erica Gansemer
• 金额: $ 1.51万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2022-05-27
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10386489
• 关键词: Affect; Animals; Attenuated; Budgets; Cell physiology; Cells; Cessation of life; Cholesterol; Chronic; Citric Acid Cycle; Communication; Confocal Microscopy; Data; Development; Diet; Disease; Endoplasmic Reticulum; Environment; Equilibrium; Fatty acid glycerol esters; Fructose; Genetic Transcription; Glutathione; Glutathione Disulfide; Glutathione Reductase; Goals; Health; Hepatic; Hepatocyte; Homeostasis; Individual; Inflammation; Isocitrate Dehydrogenase; Isoenzymes; Knockout Mice; Lead; Link; Lipids; Liver; Mediating; Metabolic; Metabolic Diseases; Metabolism; Mitochondria; Mitochondrial Matrix; Molecular; Molecular and Cellular Biology; Mus; NADP; Nutrient; Obesity; Organelles; Organism; Outcome; Oxidation-Reduction; Oxides; Pathway interactions; Physiological; Predisposition; Process; Production; Proteins; Research; Role; Signal Transduction; Source; Stable Isotope Labeling; Stress; System; Testing; Tissues; Training; Translations; Tricarboxylic Acids; Work; base; endoplasmic reticulum stress; experience; experimental study; glutathione peroxidase; in vivo; lipid metabolism; liver injury; mitochondrial dysfunction; mitochondrial metabolism; non-alcoholic fatty liver disease; nonalcoholic steatohepatitis; novel; novel therapeutics; nutrient deprivation; oxidative damage; premature; protein folding; proteostasis; pyruvate carrier; ratiometric; sensor

Project Summary Cellular homeostasis is critical not only for the health of individual cells, but for an organism as a whole. Dysregulation of cellular processes, such as metabolism, contribute to the development of numerous diseases that have been difficult to fully characterize and treat thus far. Difficulty with treatment arises in part from the intricacy of cellular metabolism. The mitochondria are the primary metabolic organelles, and they cooperate with other organelles, including the endoplasmic reticulum (ER). The ER is responsible for lipid packaging and oxidative protein folding, and is sensitive to perturbations that disrupt these processes. Perturbations to ER function, better known as ER stress, result in activation of an adaptive pathway that coordinates transcription, translation, and metabolism to return the cell to homeostasis. However, chronic ER stress often leads to disease, including metabolic diseases such as non-alcoholic steatohepatitis (NASH). To date, NASH research has focused on either the mitochondria or ER, but not both. I recently showed that flux through the mitochondrial tricarboxylic acid (TCA) cycle impacts ER homeostasis through cellular redox signaling via NADPH and glutathione. This observation led to the hypothesis that TCA flux could communicate nutrient availability to the ER through NADPH and glutathione in an effort to balance the cellular redox budget and prime the ER for an influx of proteins or lipids. This also led to the hypothesis that redox communication between the ER and mitochondria results in ER stress-induced NASH. These two hypotheses are not mutually exclusive; it is possible that this redox mechanism is responsible for communicating nutrient status to the ER, but that it has no impact on NASH progression. Testing these hypotheses has the potential to uncover a novel mechanism for NASH progression. In this proposal, I will rigorously test the hypothesis that NADPH and glutathione redox lead to ER stress- induced NASH when nutrients are abundant. I will utilize animals lacking the TCA isozyme, isocitrate dehydrogenase (Idh2), which generates NADPH in the mitochondrial matrix. I will assess the susceptibility of these animals to ER stress and a NASH-promoting diet, while also determining how nutrient availability regulates pathway-specific NADPH production. Additionally, I will test the hypothesis that redox signals are communicated from the mitochondria to the ER by assessing compartment-specific levels of NADPH and glutathione under varied nutrient conditions. The broad goal of this proposal is to clarify the role of NADPH and glutathione in regulating ER function based on nutrient status. Successful completion of this proposal has the potential to spur research to develop new therapeutics for NASH, and may also be applied to other metabolic diseases and metabolically active tissues.

项目摘要 细胞动态平衡不仅对单个细胞的健康至关重要，对整个有机体也是如此。 细胞过程的失调，如新陈代谢，会导致许多疾病的发生 到目前为止，这些疾病很难完全定性和治疗。治疗困难的部分原因是 细胞代谢的错综复杂。线粒体是主要的代谢细胞器，它们相互协作 与其他细胞器，包括内质网。急诊室负责脂质包装和 氧化蛋白质折叠，并对扰乱这些过程的扰动敏感。对ER的摄动 功能，更为人所知的内质网应激，导致激活一条协调转录的适应性途径， 翻译和新陈代谢，使细胞恢复到动态平衡。然而，慢性内质网应激往往会导致 疾病，包括代谢性疾病，如非酒精性脂肪性肝炎(NASH)。到目前为止，纳什研究 专注于线粒体或内质网，但不是两者都有。我最近展示了流通量通过 线粒体三羧酸(TCA)循环通过细胞氧化还原信号途径影响内质网稳态 NADPH和谷胱甘肽。这一观察结果导致了TCA通量可以传递营养物质的假设 通过NADPH和谷胱甘肽对内质网的可用性，以努力平衡细胞氧化还原预算和 为蛋白质或脂类的流入启动ER。这也导致了氧化还原通讯的假说 内质网和线粒体之间的相互作用导致内质网应激诱导的NASH。这两个假设并不是相互的。 独占；这种氧化还原机制可能负责将营养状态传达给内质网， 但这对纳什的进步没有影响。检验这些假说有可能发现一部小说 纳什进展的机制。 在这项提议中，我将严格检验NADPH和谷胱甘肽氧化还原导致内质网应激的假设- 当营养丰富时诱发NASH。我将利用缺乏TCA同工酶的动物，异柠檬酸 脱氢酶(IDH2)，在线粒体基质中产生NADPH。我将评估其易感性 这些动物对内质网应激和促进NASH的饮食，同时也决定了如何获得营养 调节特定途径的NADPH的产生。此外，我将测试氧化还原信号是 通过评估室内特定水平的NADPH和内质网从线粒体传递到内质网 不同营养条件下的谷胱甘肽。这项提案的广泛目标是澄清NADPH和 谷胱甘肽在营养状态调节内质网功能中的作用。这项提案的成功完成将使 有潜力推动研究为NASH开发新的治疗方法，也可能应用于其他代谢 疾病和代谢活跃的组织。