CD73 is a multi-functional protein that regulates liver injury

CD73是一种调节肝损伤的多功能蛋白

• 批准号: 9882993
• 负责人: Natasha T Snider
• 金额: $ 34.43万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9882993
• 关键词: 5' -Nucleotidase; ATF2 gene; Active Sites; Acute; Address; Adenosine; Adenosine Monophosphate; Albumins; Alcohols; Animals; Antibodies; Apoptosis; Binding; Biochemical; Biological; Biology; Cardiovascular Diseases; Catalytic Domain; Cell surface; Cells; Cessation of life; Chemicals; Chronic; Chronic Hepatitis C; Cirrhosis; Clinical; Couples; Data; Development; Diet; Disease; Disease Progression; Down-Regulation; Enzymes; Estrogen receptor positive; Ethanol; Etiology; Event; Fibrosis; Genes; Genetic Transcription; Goals; Hepatocyte; High Fat Diet; Homeostasis; Human; Image; In Vitro; Inflammation; Injury; Knockout Mice; Leukotrienes; Ligands; Lipids; Liver; Liver diseases; LoxP-flanked allele; Malignant Neoplasms; Messenger RNA; Metabolic; Metabolism; Mitochondria; Modeling; Molecular; Mus; Names; National Institute on Alcohol Abuse and Alcoholism; Pain; Pathology; Patients; Pharmaceutical Preparations; Phosphorylation; Play; Predisposition; Primary carcinoma of the liver cells; Protein Isoforms; Proteins; Proteomics; RNA Splicing; Recombinants; Regulation; Research Personnel; Resistance; Resources; Role; Sampling; Signal Transduction; Site; Slice; Solid; Stress; Suggestion; Thromboxane B2; Tissues; Transcript; Up-Regulation; Variant; Virus; Wild Type Mouse; Work; base; chronic liver disease; endoplasmic reticulum stress; experimental study; extracellular; feeding; foot; glycoproteomics; glycosylation; hepatocellular injury; hepatocyte injury; improved; in vivo; insight; liver function; liver injury; loss of function; mRNA Precursor; mutant; non-alcoholic fatty liver disease; nonalcoholic steatohepatitis; novel; problem drinker; protein function; receptor; resilience; screening; therapeutic target

Abstract. Their central importance to the synthetic, secretory and metabolic functions of the liver renders hepatocytes particularly vulnerable to injury. Reinforcing hepatocyte resilience to damaging insults holds potential to block liver disease progression at early stages, independent of etiology. To that end, ecto-5’-nucleotidase (CD73) is a promising novel liver disease target, as it plays critical roles in multiple mouse liver injury models, and is dysregulated in livers of patients with chronic liver diseases of multiple etiologies. The classical function of CD73 is metabolism of extracellular adenosine monophosphate (AMP) to adenosine. We found that global CD73-/- mice are resistant to chemically-induced hepatocellular injury, an unexpected finding given that liver injury induces near-complete loss of cell surface CD73 AMPase activity in wild-type mice. This points to alternative functions, which is also supported by our identification of a novel, catalytically-inactive CD73 isoform (CD73S) in advanced human liver disease. We observe differences in apoptosis-related signaling in primary hepatocytes expressing the two different human CD73 isoforms. CD73 binds two bioactive lipids in vitro, suggesting that it may regulate lipid homeostasis. Our central hypothesis is that non-enzymatic and alternative isoform-related mechanisms of hepatocyte CD73 promote liver injury and disease progression. The hypothesis will be addressed via two specific aims: (i) Define the non-enzymatic and isoform-specific functions of CD73 in hepatocytes and (ii) Examine the in vivo and tissue-level mechanisms of hepatoprotection in the absence of CD73. Our approach for Aim 1 will couple high throughput ligand screening, high content imaging, and proteomics with detailed biochemical, molecular and cell-biological assessments to determine if CD73 is a lipid-sensing receptor or a regulator of ER stress, and to determine the specific function of the non-catalytic CD73S variant in hepatocyte resistance to stress. For Aim 2, we will examine liver-specific contributions of CD73 in vivo using two models of alcohol and high fat diet-induced injury and our newly-generated liver-specific CD73-/- mice. We will utilize recombinant enzyme in vivo and precision-cut liver slices to perform mechanistic rescue and loss-of-function studies. This work will lead to a thorough integration of CD73 function in hepatocytes with the potential to yield novel mechanistic approaches for hepatoprotection.

抽象的。 它们对肝脏呈肝细胞的合成，秘书和代谢功能的核心重要性 增强肝细胞对破坏伤害的弹性有可能阻止 肝病在早期阶段的进展，与病因无关。为此，Ecto-5'-核苷酸酶（CD73）是一个 有希望的新型肝病靶标，因为它在多个小鼠肝损伤模型中起关键作用，并且 多种病因的慢性肝病患者的生活失调。 CD73的经典功能 是细胞外腺苷单磷酸（AMP）的代谢。我们发现全球CD73 - / - 小鼠 对化学诱导的肝细胞质损伤具有抵抗力，这是一个意外的发现，鉴于肝损伤会影响 野生型小鼠中细胞表面CD73 Ampase活性的几乎完全丧失。这表明替代功能， 这也是我们对高级催化活性CD73同工型（CD73）的识别所支持的 人肝病。我们观察到表达的原发性肝细胞中与凋亡相关的信号传导的差异 两个不同的人CD73同工型。 CD73在体外结合了两种生物活性脂质，表明它可能调节 脂质稳态。我们的中心假设是，非酶和替代同工型的机制 肝细胞CD73促进肝损伤和疾病进展。该假设将通过两个特定 目的：（i）定义CD73在肝细胞中的非酶和同工型特异性功能，（ii）检查 在没有CD73的情况下，体内和组织水平的机理。我们的目标1将 夫妇具有详细生化的高吞吐配体筛选，高含量成像和蛋白质组学， 分子和细胞生物学评估，以确定CD73是脂质的接收器还是ER的调节剂 应力，并确定非催化CD73S变体在肝细胞抗性中的特定功能 压力。对于AIM 2，我们将使用两种酒精和 高脂肪饮食诱导的损伤和我们新生成的肝脏特异性CD73 - / - 小鼠。我们将使用重组 酶在体内和精确切割肝切片中进行机械救援和功能丧失研究。这 工作将导致肝细胞中CD73功能的彻底整合，并有可能产生新颖 肝保护措施的机械方法。