Thioesterase-mediated lipotoxicity in liver and thermogenic adipose tissue

肝脏和产热脂肪组织中硫酯酶介导的脂毒性

• 批准号: 10468796
• 负责人: Baran Ersoy
• 金额: $ 42.38万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-13 至 2026-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10468796
• 关键词: Ablation; Acetyl Coenzyme A; Acyl Coenzyme A; Adipocytes; Adipose tissue; Anabolism; Biological Availability; Body Weight decreased; Caenorhabditis elegans; Cells; Ceramides; Citric Acid Cycle; Climate; Closure by clamp; Consumption; Data; Deacetylase; Defect; Diet; Dietary Fats; Dietary Sugars; Diglycerides; Disease; Endoplasmic Reticulum; Energy Metabolism; Exhibits; Family member; Fatty Acids; Fractionation; Glucose; Goals; Hepatic; Hepatocyte; Histology; Homeostasis; Human; Hydrolysis; Immunoblot Analysis; Impairment; In Vitro; Indirect Calorimetry; Inner mitochondrial membrane; Insulin Resistance; Intervention; Knockout Mice; Lipids; Liver; Lysine; Measurement; Measures; Mediating; Membrane; Metabolic; Metabolic Diseases; Mission; Mitochondria; Mitochondrial Matrix; Molecular; Mus; National Institute of Diabetes and Digestive and Kidney Diseases; Nutrient; Obesity; Outcome; Overnutrition; Oxidative Stress; Pathogenesis; Pathway interactions; Pharmacology; Phosphorylation; Plasma; Prevention; Production; Protein Acetylation; Protein Kinase C; Proteins; Public Health; Publishing; RNA Interference; Reactive Oxygen Species; Recombinants; Regulation; Research; Research Proposals; Resolution; Role; Sirtuins; Testing; Therapeutic; Thermogenesis; Tissues; base; design; endoplasmic reticulum stress; experimental study; glucose metabolism; glucose production; improved; insulin sensitivity; insulin signaling; knock-down; lipid biosynthesis; lipid metabolism; lipidomics; metabolomics; non-alcoholic fatty liver disease; novel; novel therapeutic intervention; protein activation; response; sugar; trafficking

PROJECT SUMMARY/ABSTRACT Obesity-induced lipotoxicity is the primary pathophysiological defect that predisposes to non-alcoholic fatty liver disease (NAFLD). Because current management options remain limited, identification of new regulatory mechanisms that govern the maladaptive response to overnutrition will serve to identify novel opportunities for pharmacologic intervention. Acyl-CoA thioesterases (Acots) control the cellular utilization of fatty acids by hydrolyzing acyl-CoA into non-esterified fatty acids. Our long-term goal is to define how aberrant Acot activity can be leveraged for therapeutic purposes. The objective of this research is to determine the mechanisms by which Acot9-mediated hydrolysis of acetyl-CoA culminates in metabolic disease. Our preliminary data indicates that Acot9 locates to the inner membrane (IM) of the mitochondria in the liver where it traffics acetyl-CoA towards the citric acid (TCA) cycle. This results in increased hepatic glucose production (HGP) and de novo lipogenesis (DNL) as well as lipotoxicity as evidenced by reactive oxygen species (ROS) and hepatic insulin resistance. In addition to TCA cycle, Acot9 increased acetyl-CoA supply for lysine acetylation of proteins (AcK) by controlling acetyl-CoA bioavailability and by inhibiting the deacetylase sirtuin 3 (Sirt3), which reduces ROS by inhibiting AcK. In contrast to liver, in thermogenic adipose tissue (BAT), cold-induced translocation of Acot9 from IM into mitochondrial matrix suppressed thermogenesis by trafficking acetyl-CoA away from TCA cycle. Our central hypothesis is that obesity-induced activation of Acot9 impairs nutrient homeostasis by promoting lipotoxicity in the liver and by limiting thermogenesis in BAT. The rationale is that the mechanisms of acetyl- CoA trafficking by Acot9 will reveal novel targets for the prevention of lipotoxicity and its pathophysiological consequences. The central hypothesis will be tested in three specific aims: 1) To identify the molecular mechanisms by which hepatic Acot9 promotes hepatic lipotoxicity; 2) To elucidate the mechanisms by which Acot9 in BAT limits thermogenesis; and 3) To determine the mechanisms by which Acot9 controls AcK and ROS in the liver. In Aim 1, the mechanisms of Acot9-induced lipotoxicity, HGP and DNL will be elucidated in mice with liver-specific ablation of Acot9 (Acot9LKO) using lipidomics and metabolomics. Impact on insulin signaling and lipotoxic pathways will be determined in mice and primary hepatocytes. Aim 2 will use mice with BAT-specific ablation of Acot9 for the indirect calorimetry measurements in climate-controlled cages. Clamp, tissue histology and metabolomics will assess the metabolic function of Acot9 in BAT. Cultured brown adipocytes and recombinant Acot9 will be used to determine the mechanism of Acot9 translocation into mitochondrial matrix. Aim 3 will use Acot9LKO/Sirt3–/– double knockout mice to determine the role of Sirt3 in Acot9-mediated regulation of AcK and ROS in the liver. Overall, this proposal will elucidate new mechanisms of thioesterase-mediated control of acetyl-CoA utilization. This is significant because acetyl-CoA is the common breakdown end-product of nearly all dietary lipids and sugars. These studies are expected to establish Acot9 as a tractable target for the management of NAFLD.

项目摘要/摘要 肥胖引起的脂肪毒性是易于非酒精脂肪肝的主要病理生理缺陷 疾病（NAFLD）。由于当前管理选项仍然有限，因此确定新监管 管理对营养不良的适应不良反应的机制将有助于确定新的机会 药理干预。酰基-COA硫酯酶（ACOTS）控制脂肪酸的细胞利用 将酰基二氧化碳水解为非酯化脂肪酸。我们的长期目标是定义异常活动 可以将其用于治疗目的。这项研究的目的是确定 ACOT9介导的乙酰氧气水解最终在代谢疾病中。我们的初步数据指示 该ACOT9位于肝脏中的线粒体的内膜（IM）上 朝向柠檬酸（TCA）周期。这导致肝葡萄糖产生（HGP）和从头开始增加 活性氧（ROS）和肝胰岛素证明了脂肪生成（DNL）以及脂肪毒性 反抗。除TCA周期外，ACOT9增加了蛋白质赖氨酸乙酰-COA（ACK）的乙酰-COA供应 通过控制乙酰-COA生物利用度并抑制脱乙酰基酶Sirtuin 3（SIRT3），从而减少ROS 通过抑制ACK。与肝脏相反，在热脂肪组织（BAT）中，冷诱导的ACOT9易位 从IM到线粒体基质，通过运输乙酰辅酶A抑制了从TCA循环的热生成。 我们的中心假设是，肥胖引起的ACOT9激活通过促进而损害营养稳态 肝脏中的脂肪毒性并通过限制蝙蝠中的热发生。理由是乙酰基的机制 ACOT9进行的COA运输将揭示预防脂肪毒性及其病理生理学的新目标 结果。中央假设将以三个特定的目的进行测试：1）确定分子 肝ACOT9促进肝脂肪毒性的机制； 2）阐明的机制 ACOT9在BAT中限制了热发生； 3）确定ACOT9控制ACK和的机制 ROS在肝脏中。在AIM 1中，ACOT9诱导的脂肪毒性，HGP和DNL的机制将在 使用脂质组学和代谢组学的ACOT9（ACOT9LKO）肝脏特异性消融的小鼠。对胰岛素的影响 信号传导和脂肪毒性途径将在小鼠和原发性肝细胞中确定。 AIM 2将使用小鼠与 ACOT9的BAT特异性消融，用于气候控制笼中间接量热法测量。夹钳， 组织学和代谢组学将评估ACOT9在BAT中的代谢功能。培养的棕色 脂肪细胞和重组ACOT9将用于确定ACOT9易位的机理 线粒体基质。 AIM 3将使用ACOT9LKO/SIRT3 - / - 双敲除小鼠来确定SIRT3的作用 ACOT9介导的肝脏中ACK和ROS的调节。总体而言，该建议将阐明新机制 硫酯酶介导的乙酰辅酶A使用的控制。这很重要，因为乙酰辅酶A是 几乎所有饮食脂质和糖的常见末期产物。这些研究有望 将ACOT9建立为NAFLD管理的可容纳目标。