Mechanisms of immunoproteasome-mediated metabolic disorders

免疫蛋白酶体介导的代谢紊乱的机制

• 批准号: 10398812
• 负责人: Do-Hyung Kim
• 金额: $ 38.61万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10398812
• 关键词: Address; Anti-Inflammatory Agents; Autoimmune Diseases; Binding; Catalytic Domain; Cell physiology; Cells; Chemicals; Chronic; Chronic Active Hepatitis; Cirrhosis; Complex; Development; Digestion; Disease; Energy Metabolism; Genes; Genetic; Genetic Polymorphism; Goals; Health; Hepatic; Hepatocyte; High Fat Diet; Homeostasis; Human; Immune; Impairment; Inflammation; Inflammatory; Inflammatory Response; Insulin Resistance; Knowledge; Label; Link; Lipids; Liver; Mediating; Mediator of activation protein; Metabolic; Metabolic Diseases; Metabolic Pathway; Metabolism; Methods; Mus; Mutation; Nutritional status; Obesity; Outcome; Oxidative Stress; PPAR alpha; Pathway interactions; Patients; Peptides; Phosphorylation; Play; Polyubiquitination; Population; Proteins; Proteomics; Rare Diseases; Research; Role; Signal Transduction; System; Tissues; Ubiquitin; Validation; base; biological adaptation to stress; cytokine; human disease; improved; inhibitor; innovation; insulin sensitivity; lipid metabolism; liver biopsy; mouse model; multicatalytic endopeptidase complex; novel; particle; prevent; therapeutic target

ABSTRACT The immunoproteasome is an inducible type of proteasome whose expression is enhanced by inflammation and oxidative stress. Although the immunoproteasome was found about 30 years ago, the function of the immunoproteasome is poorly understood except its role in producing antigenic peptides. Recent studies have shown that the immunoproteasome regulates cell signaling, differentiation and cytokine secretion in non-immune cells. We found that 95% of proteasome is the immunoproteasome in the mouse liver when mTORC1 is constitutively active. Numerous mutations and polymorphisms have been identified in immunoproteasome-specific genes among human populations of metabolic, autoimmune, and rare diseases. The immunoproteasome level is highly increased in proportion to the degree of inflammation in liver biopsies from patients who have chronic active hepatitis or cirrhosis. Despite the relevance of the immunoproteasome in many human diseases, its functions remain poorly understood mainly due to the lack of knowledge on its target substrates. The objective of this proposed study is to determine the mechanism by which the immunoproteasome digests its preferential target proteins and determine how the selective digestion impairs hepatic and global energy metabolism. We developed mice where the immunoproteasome is depleted specifically in the liver. Interestingly, the depletion of hepatic immunoproteasome led to beneficial metabolic outcomes protecting the mice against obesity, insulin resistance and steatosis. As a possible mechanism, we hypothesize that the immunoproteasome induces metabolic reprogramming by selective digestion of proteins involved in metabolic homeostasis and anti-inflammation. We have three specific aims to address the hypothesis. First, we will define the immunoproteasome as a crucial mediator that impairs hepatic lipid metabolism using a genetic mouse model, primary hepatocytes, and immunoproteasome inhibitors. Second, we will determine the role of the immunoproteasome in oxidative stress-induced insulin resistance. Based on our preliminary study, we hypothesize that the immunoproteasome suppresses Akt-dependent metabolism in chronic oxidative stress or inflammation. Using genetic and chemical approaches, we will demonstrate that the immunoproteasome negatively regulates Akt signaling under oxidative stress and define the immunoproteasome as a promising therapeutic target for insulin resistance. Third, we will use quantitative proteomics and proximity-based labeling methods to comprehensively identify target proteins of the immunoproteasome. We will choose a handful identified proteins and validate them as targets of the immunoproteasome. The identified proteins will allow us to define novel metabolic pathways regulated by the immunoproteasome. The outcomes will innovate our understanding of the immunoproteasome by defining the immunoproteasome as a key mediator and as a promising therapeutic target for inflammatory metabolic diseases.

抽象的 免疫蛋白酶体是一种诱导型蛋白酶体，其表达因炎症而增强 和氧化应激。尽管免疫蛋白酶体大约30年前就被发现了，但其功能 除了免疫蛋白酶体在产生抗原肽方面的作用外，人们对免疫蛋白酶体了解甚少。最近的研究 研究表明，免疫蛋白酶体调节细胞信号传导、分化和细胞因子分泌 非免疫细胞。我们发现小鼠肝脏中95%的蛋白酶体是免疫蛋白酶体 mTORC1 具有组成型活性。已鉴定出许多突变和多态性 代谢、自身免疫和罕见人群中的免疫蛋白酶体特异性基因 疾病。免疫蛋白酶体水平随着炎症程度的增加而显着增加 慢性活动性肝炎或肝硬化患者的肝活检。尽管相关性 免疫蛋白酶体在许多人类疾病中发挥作用，但其功能仍知之甚少，主要是由于缺乏 关于其目标底物的知识。这项研究的目的是确定机制 免疫蛋白酶体通过它消化其优先靶蛋白并确定选择性如何 消化损害肝脏和整体能量代谢。我们开发了免疫蛋白酶体的小鼠 特别是在肝脏中被耗尽。有趣的是，肝免疫蛋白酶体的耗竭导致 有益的代谢结果可以保护小鼠免受肥胖、胰岛素抵抗和脂肪变性的影响。作为一个 可能的机制，我们假设免疫蛋白酶体通过以下方式诱导代谢重编程 选择性消化参与代谢稳态和抗炎的蛋白质。我们有三个 解决假设的具体目标。首先，我们将免疫蛋白酶体定义为关键介质 使用遗传小鼠模型、原代肝细胞和 免疫蛋白酶体抑制剂。其次，我们将确定免疫蛋白酶体在氧化中的作用 压力引起的胰岛素抵抗。根据我们的初步研究，我们假设 免疫蛋白酶体抑制慢性氧化应激或炎症中 Akt 依赖性代谢。 使用遗传和化学方法，我们将证明免疫蛋白酶体对 在氧化应激下调节 Akt 信号传导并将免疫蛋白酶体定义为一种有前途的治疗方法 胰岛素抵抗的目标。第三，我们将使用定量蛋白质组学和基于邻近的标记 全面鉴定免疫蛋白酶体靶蛋白的方法。我们会选择少数 鉴定蛋白质并验证它们作为免疫蛋白酶体的靶标。鉴定出的蛋白质将允许 我们定义了由免疫蛋白酶体调节的新代谢途径。结果将创新 通过将免疫蛋白酶体定义为关键介质和作为我们对免疫蛋白酶体的理解 炎症代谢疾病的一个有前景的治疗靶点。