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.

项目概要 细胞稳态不仅对于单个细胞的健康至关重要，而且对于整个有机体也至关重要。 细胞过程（例如新陈代谢）的失调会导致多种疾病的发生 迄今为止，很难充分描述和治疗这些问题。治疗困难部分源于 细胞代谢的复杂性。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（ER）。 ER 负责脂质包装和 氧化蛋白质折叠，并且对破坏这些过程的扰动敏感。对 ER 的干扰 功能，更好地称为内质网应激，导致协调转录的适应性途径的激活， 翻译和新陈代谢使细胞恢复稳态。然而，慢性 ER 应激通常会导致 疾病，包括代谢性疾病，例如非酒精性脂肪性肝炎（NASH）。迄今为止，NASH 研究 重点关注线粒体或内质网，但不是同时关注两者。我最近表明，通过 线粒体三羧酸 (TCA) 循环通过细胞氧化还原信号传导影响 ER 稳态 NADPH 和谷胱甘肽。这一观察结果得出了这样的假设：TCA 通量可以传递营养物质 通过 NADPH 和谷胱甘肽向 ER 提供可用性，以平衡细胞氧化还原预算和 为内质网做好蛋白质或脂质流入的准备。这也导致了氧化还原通讯的假设 ER 和线粒体之间的相互作用导致 ER 应激诱发 NASH。这两个假设并不相互 独家的;这种氧化还原机制可能负责将营养状态传达给内质网， 但它对 NASH 进展没有影响。测试这些假设有可能发现一部小说 NASH 进展的机制。 在这个提案中，我将严格检验 NADPH 和谷胱甘肽氧化还原导致 ER 应激的假设 - 当营养丰富时，会诱发 NASH。我将利用缺乏 TCA 同工酶、异柠檬酸的动物 脱氢酶 (Idh2)，在线粒体基质中生成 NADPH。我将评估其敏感性 这些动物面临 ER 压力和促进 NASH 的饮食，同时还确定营养的可用性 调节途径特异性 NADPH 的产生。此外，我将测试氧化还原信号是的假设 通过评估 NADPH 的隔室特异性水平从线粒体到 ER 进行通讯 不同营养条​​件下的谷胱甘肽。该提案的总体目标是阐明 NADPH 的作用和 谷胱甘肽根据营养状况调节 ER 功能。本提案的顺利完成 有潜力刺激研究开发 NASH 新疗法，也可能应用于其他代谢 疾病和代谢活跃的组织。