Opposing Effects of Prostaglandin E2 EP3 and EP4 Receptors on Mitochondrial

前列腺素 E2 EP3 和 EP4 受体对线粒体的相反作用

• 批准号: 10391357
• 负责人: PAMELA HARDING
• 金额: $ 53.74万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-15 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10391357
• 关键词: Adult; Affect; Affinity; Agonist; Angiotensin II; Biochemical; Cardiac; Cardiac Myocytes; Cardiovascular Diseases; Carnitine; Cause of Death; Complex; Coupled; Data; Dependence; Dilated Cardiomyopathy; Dinoprostone; Disease; Disease Progression; Down-Regulation; EP4 receptor; Echocardiography; Electron Transport; Energy Metabolism; Energy-Generating Resources; Event; Fatty Acids; Funding; GTP-Binding Protein alpha Subunits, Gs; Genes; Glucose; Heart; Heart Diseases; Heart Injuries; Heart failure; Histology; Hypertension; Impairment; In Vitro; Inflammation; Kinetics; Knockout Mice; Knowledge; Laboratories; Measurement; Measures; Mediating; Membrane Potentials; Messenger RNA; Mitochondria; Morbidity - disease rate; Mouse Strains; Mus; Myocardial Infarction; NMR Spectroscopy; NR4A2 gene; Orphan; Oxidative Phosphorylation; Palmitates; Pathogenesis; Pathologic; Persons; Phenotype; Physiological; Play; Process; Prostaglandin Production; Prostaglandins; Proteins; Respiratory Chain; Role; Signal Pathway; Signal Transduction; Superoxide Dismutase; Superoxides; Testing; Tissues; Transferase; Transgenic Mice; United States; United States National Institutes of Health; Up-Regulation; WFDC2 gene; cardiovascular disorder therapy; cost; fatty acid oxidation; heart function; imaging study; improved; in vivo; interdisciplinary approach; knock-down; lipidomics; mitochondrial dysfunction; mitochondrial membrane; mortality; mouse model; novel; novel therapeutics; overexpression; oxidation; prevent; receptor; transcription factor; transcriptomics

ABSTRACT Heart disease and heart failure are important causes of morbidity and mortality, affecting approximately 300 million people, at an enormous cost. Although current treatments slow the progression of these diseases, there has been little progress in preventing the compensated heart transitioning to that of a failing one. The Prostaglandin E2 (PGE2) receptor subtypes EP3 and EP4 are most abundant in the heart and activate different signaling pathways (Gαi for EP3, Gαs for EP4). Compelling data from my laboratory shows that EP3 expression is increased in the pathologically diseased heart produced by myocardial infarction (MI) or Angiotensin II- dependent hypertension (Ang II-HTN), that stimulation of the EP3 receptor decreases cardiac contractility whereas EP4 increases it and that overexpression of EP4 in the failing heart improves cardiac function. The failing heart switches from fatty acid (FA) oxidation to reliance on glucose. Coupled with this are alterations in mitochondrial function. Thus, mitochondrial dysfunction is an important player in the pathogenesis of heart failure. Our previous gene array data showed dramatic down regulation of mitochondrial genes in mice in which the EP4 receptor was deleted in cardiomyocytes; allowing PGE2 to act via the EP3 receptor and new data shows that an EP3 agonist reduces Complex I activity and ATP levels in adult mouse cardiomyocytes. mRNAs for proteins that alter both FA oxidation and their transport into mitochondria; specifically, carnitine palmitoyl transferase (CPT) were also down regulated in EP4 KO hearts. In other tissues, CPT activity was reportedly regulated by the transcription factor/orphan receptor NR4A2 (Nurr1) in a PGE2-dependent process but whether this occurs in the heart is unstudied. Since heart failure is characterized by reduced FA oxidation, we propose the novel overall hypothesis: EP3 is increased during cardiac injury and impairs mitochondrial function due to reduced fatty acid import via diminished CPT activity. This is mediated by decreased activity of the transcription factor, NR4A2. Ultimately these events contribute to heart failure. To test this hypothesis, we propose 3 aims that will use a new conditional and cardiomyocyte-specific EP3 KO mouse model coupled with an EP3 overexpressing transgenic mouse to determine whether upregulation of cardiomyocyte EP3 contributes to impaired contractile function and reduced mitochondrial function in heart failure caused by Ang II-HTN and MI. The study also examines whether PGE2 via its EP3 receptor reduces import of fatty acids into mitochondria via decreased activity of the transcription factor NR4A2 which subsequently reduces CPT activity; and whether these events reduce subsequent ATP levels. The proposal employs a multidisciplinary approach including physiological, biochemical and imaging studies that will impact the treatment of heart failure.

摘要 心脏病和心力衰竭是发病率和死亡率的重要原因，影响约300人。 百万人，付出了巨大的代价。尽管目前的治疗方法延缓了这些疾病的进展，但 在防止代偿心脏过渡到衰竭心脏方面进展甚微。这个 前列腺素E2(PGE2)受体亚型EP3和EP4在心脏中含量最丰富，其激活方式不同 信号通路(EP3为GαI，EP4为GαS)。来自我的实验室的令人信服的数据表明，EP3表达 在心肌梗死(MI)或血管紧张素II产生的病理性心脏中增加- 依赖性高血压(Ang II-HTN)，刺激EP3受体降低心肌收缩能力 而EP4则增加了它的表达，并且在衰竭的心脏中过度表达EP4可以改善心脏功能。这个 衰竭的心脏从脂肪酸(FA)氧化转变为依赖葡萄糖。与此相伴随的是在 线粒体功能。因此，线粒体功能障碍是心脏发病机制中的一个重要因素。 失败了。我们先前的基因阵列数据显示，在小鼠中，线粒体基因显著下调 心肌细胞中EP4受体被删除；允许PGE2通过EP3受体和新数据发挥作用 显示EP3激动剂降低成年小鼠心肌细胞的复合体i活性和ATP水平。MRNAs 用于改变FA氧化及其向线粒体转运的蛋白质；具体地说，肉碱棕榈酰 转移酶(CPT)在EP4KO心脏中也表达下调。据报道，在其他组织中，CPT活性 在PGE2依赖的过程中受转录因子/孤儿受体NR4A2(Nurr1)的调节，但是否 这种情况发生在心脏是未经研究的。由于心力衰竭的特征是FA氧化减少，我们建议 新的总体假说：EP3在心脏损伤期间增加，并因以下原因损害线粒体功能 通过降低CPT活性来减少脂肪酸进口。这是由转录活性降低所介导的。 因子，NR4A2。最终，这些事件会导致心力衰竭。为了验证这一假设，我们提出了三个目标 这将使用一种新的条件性和心肌细胞特异性的EP3 KO小鼠模型和EP3 过表达转基因小鼠以确定心肌细胞EP3的上调是否有助于 Ang II-HTN和MI所致心力衰竭时心肌收缩功能受损，线粒体功能降低。 这项研究还检查了前列腺素E_2是否通过其EP3受体减少了脂肪酸进入线粒体 通过降低转录因子NR4A2的活性从而降低CPT的活性；以及 这些事件会降低随后的ATP水平。该提案采用了多学科的方法，包括 将影响心力衰竭治疗的生理、生化和成像研究。