Investigating Mechanisms of Acetyl-CoA Sensing and Its Implications in Non-Alcoholic Fatty Liver Disease

研究乙酰辅酶A传感机制及其在非酒精性脂肪肝中的意义

• 批准号: 10251911
• 负责人: Joyce Ying Liu
• 金额: $ 3.35万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10251911
• 关键词: ATP Citrate (pro-S)-Lyase; Acetate-CoA Ligase; Acetates; Acetyl Coenzyme A; Address; Affect; Amino Acids; Biological; Carbohydrates; Carbon; Catabolism; Cell physiology; Cells; Cholesterol; Citrates; Clinical; Clinical Treatment; Clinical Trials; Coenzyme A; Data; Defect; Dietary Fats; Disease; Disease Progression; Enzymes; Family; Family member; Fatty Acids; Fatty Liver; Fatty acid glycerol esters; Fructose; Gene Expression; Genes; Genetic; Genetic Models; Genetic Transcription; Goals; Health; Hepatic; High Fat Diet; Homeostasis; Hypoxia; In Vitro; Individual; Knockout Mice; Life; Lipids; Liver; Liver diseases; Mammalian Cell; Mediating; Messenger RNA; Metabolic; Metabolic Diseases; Metabolic stress; Metabolism; Mitochondria; Modeling; Monitor; Nuclear; Nutrient; Organism; Pathogenesis; Pathology; Pathway interactions; Phase III Clinical Trials; Phenotype; Physiology; Play; Positioning Attribute; Prevalence; Process; Production; Protein Isoforms; Proteins; Public Health; Regulation; Reporting; Role; Signal Pathway; Testing; Therapeutic; Tissues; Ubiquinone; Up-Regulation; Work; base; chronic liver disease; detection of nutrient; dietary excess; fatty acid oxidation; genetic manipulation; hypercholesterolemia; improved; in vivo; in vivo Model; inhibitor/antagonist; insight; lipid biosynthesis; mevalonate; mitochondrial dysfunction; non-alcoholic fatty liver disease; novel; programs; response; tool; transcription factor; transcription factor S-II; treatment strategy

PROJECT SUMMARY Nutrient sensing (i.e. the ability of cells and organisms to sense, report on, and respond to nutrient availability) is a fundamental mechanism that is essential to life and health, but often dysregulated in the context of diseases. While the discovery of sensing mechanisms for some nutrients, such as amino acids and ATP, have yielded critical insight into their implications for disease, the mechanisms other essential metabolites may be sensed remains unexplored. Acetyl-CoA is a metabolite at the intersection of several catabolic, anabolic, and signaling pathways, and therefore, may be uniquely positioned to report on nutrient availability. Indeed, data from our lab and others indicates that acetyl-CoA availability is sensed. Specifically, our lab has previously shown that upon deletion or inhibition of ATP-citrate lyase (ACLY), cells and tissues upregulate Acetyl-CoA synthetase short chain family member 2 (ACSS2) in order to maintain nuclear-cytosolic pools of acetyl-CoA. However, we have a very limited understanding of the mechanisms by which cells sense acetyl-CoA and how this sensing pathway can subsequently engage adaptive responses when acetyl-CoA production via ACLY is compromised. Notably, a liver-specific inhibitor against ACLY is currently in phase 3 clinical trials for the treatment of hypercholesterolemia. Despite this clinical therapeutic and the potential for the inhibitor to be widely used in individuals with metabolic diseases, studies with genetic models of hepatic ACLY deficiency are lacking, and in particular, no studies have investigated the implications of ACLY loss and subsequent compensatory ACSS2 upregulation in metabolic liver disease, such as non-alcoholic fatty liver disease (NAFLD). Based on my preliminary data, I hypothesize i) that the sensitivity of the mevalonate and cholesterol pathway to ACLY loss mediates ACSS2 upregulation via activation of SREBP transcription factors and ii) that suppression of lipogenic acetyl-CoA production and activation of this sensing mechanism has implications in the pathogenesis of NAFLD by causing a defect in mitochondrial function and fatty acid oxidation. I will test this hypothesis, first (aim 1) through quantification of cholesterol pathway metabolites and assessment of SREBP transcriptional activity, using both an in vitro and in vivo model of ACLY deficiency. Further, I will characterize (aim 2) the effect of suppressing lipogenic acetyl-CoA production an in vivo model of hepatic steatosis. Specifically, I will investigate how a deficit in lipogenic acetyl-CoA production alters fatty acid oxidation and mitochondrial function, and determine whether these changes are dependent on alterations in levels of the mevalonate pathway product, ubiquinone. Overall, I expect the results of this study to address an essential mechanism in acetyl-CoA sensing, as well as the functional consequences of targeting acetyl-CoA metabolism in NAFLD, with the potential to impact treatment strategies of existing therapeutics.

项目摘要 营养感应（即细胞和生物的能力感知，报告和响应养分的能力） 是一种对生活和健康至关重要的基本机制，但在 疾病。虽然发现某些营养素（例如氨基酸和ATP）的传感机制具有 对它们对疾病的影响产生了批判性的洞察力，其他必要代谢物可能是 感觉仍然没有探索。乙酰辅酶A是几个分解代谢，合成代谢和 因此，信号通路，因此可以独特地报告营养物的可用性。确实，数据 从我们的实验室和其他实验室中表明，乙酰辅酶A的可用性。具体来说，我们的实验室以前有 表明，在删除或抑制ATP-柠檬酸裂解酸酯（ACLY）时，细胞和组织上调乙酰辅酶A 合成酶短链家族成员2（ACSS2），以维持乙酰辅酶A的核溶质膜池。 但是，我们对细胞感知乙酰辅酶A的机制有非常有限的理解以及如何 当通过Acly产生乙酰辅酶A是 妥协。值得注意的是，针对ACLY的肝特异性抑制剂目前正在3阶段的临床试验中 治疗高胆固醇血症。尽管这种临床治疗和抑制剂的潜力 肝脏缺乏遗传模型的研究中广泛用于代谢性疾病的人 缺乏，尤其是没有研究调查了Acly损失的含义和随后的含义 代谢性ACS2代谢性肝病的上​​调，例如非酒精性脂肪肝病 （NAFLD）。基于我的初步数据，我假设i）甲甲酸和胆固醇的敏感性 通过激活SREBP转录因子，ACLY损失的途径介导ACSS2上调，ii） 抑制脂肪生成乙酰-COA的产生和这种感应机制的激活对 通过导致线粒体功能和脂肪酸氧化的缺陷，NAFLD的发病机理。我会测试这个 假设，首先通过定量胆固醇途径代谢物和SREBP评估 转录活性，同时使用体外和体内腹部缺乏模型。此外，我会描述 （AIM 2）抑制脂肪生成乙酰-COA产生的作用是肝脂肪变性的体内模型。 具体而言，我将研究脂肪生成乙酰-COA产生的不足如何改变脂肪酸氧化和 线粒体功能，并确定这些变化是否取决于 Mevalonate途径产品，泛氨基酮。总的来说，我希望这项研究的结果能够解决重要的 乙酰-COA传感的机制，以及靶向乙酰-COA代谢的功能后果 在NAFLD中，有可能影响现有治疗剂的治疗策略。