Pulmonary Vascular-Right Ventricular Axis Research Program

肺血管-右心室轴研究计划

• 批准号: 8530275
• 负责人: Serpil C. Erzurum
• 金额: $ 62.79万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8530275
• 关键词: 2-Fluoro-2-deoxyglucose; Adenylate Cyclase; Adrenergic Receptor; Agonist; Apoptosis; Binding; Biochemical; Blood Vessels; Cardiac; Cardiac Myocytes; Cause of Death; Cells; Clinical Trials; Clinical assessments; Cyclic AMP; Data; Deoxyglucose; Development; Disease; Down-Regulation; Endothelial Cells; Endothelium; Enzymes; Event; Failure; Fasting; Figs - dietary; Functional disorder; Goals; Growth; Health; Heart; Heart failure; Human; Investigation; Knowledge; Lead; Left; Link; Longitudinal Studies; Lung; Mediating; Metabolic; Metabolism; Modeling; Muscle Cells; Pathologic; Pathway interactions; Patients; Peripheral Blood Mononuclear Cell; Phenotype; Phosphatidylinositols; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiological; Placebo Control; Play; Positron-Emission Tomography; Production; Protein Dephosphorylation; Protein Kinase; Protein Phosphatase 2A Regulatory Subunit PR53; Protein phosphatase; Pulmonary Hypertension; Pulmonary artery structure; Receptor Signaling; Recovery; Recycling; Regulation; Research; Resistance; Role; Serine; Signal Transduction; Signal Transduction Pathway; Testing; Threonine; Time; Transducers; Vascular remodeling; Ventricular; carvedilol; desensitization; functional improvement; functional restoration; functional status; glucose analog; hemodynamics; human NOS3 protein; hypoxia inducible factor 1; in vivo; novel; pressure; programs; pulmonary arterial hypertension; receptor; receptor downregulation; receptor function; response; uptake

DESCRIPTION (provided by applicant): Pulmonary arterial hypertension (PAH) is a fatal disease characterized by impaired regulation of pulmonary hemodynamics and vascular growth; right ventricular failure is the leading cause of death. Our studies have identified loss of pulmonary vascular endothelial nitric oxide synthase (eNOS) activity in PAH, and that the NO deficiency leads to hypoxia-inducible factor-1 (HIF-1) activation, which results in glycolytic, proliferative, apoptosis-resistant endothelial cells that promote vascular remodeling. The mechanism(s) of eNOS activity loss is unknown. eNOS is also present in the cardiomyocyte, where NO synthesis by eNOS is cardioprotective; but eNOS has not been studied in the human PAH heart. Activation of eNOS requires enzyme dephosphorylation at Threonine 495 (T495) and phosphorylation at Serine 1177 (S1177), the latter mediated by cyclic adenosine monophosphate (cAMP)/protein kinase pathways downstream of ?-Adrenergic Receptors (?AR) [Fig 1]. Because ?AR downregulation and desensitization are found in all heart failure, we investigated ?AR in the eNOS activity loss and its consequences on the pulmonary vascular-right ventricular (RV) axis. Explanted human PAH hearts have desensitization and low numbers of ?AR, and for the first time, we show that pulmonary arterial endothelial cells (PAEC) from human PAH lungs have similarly low numbers and de- sensitization of ?AR. Preliminary data reveal that ?AR desensitization is due to deficient dephosphorylation of the receptor by phosphatases, which are inhibited by over-activation of phosphatidyl inositol 3-kinase (PI3Kg). ?AR numbers are low due to defective intracellular recycling of phosphorylated receptors. Consistent with PI3K inhibition of phosphatases, PAH PAEC and cardiomyocytes have high levels of the inactive pT495 eNOS, identifying the cause of decreased NO production upon any type of agonist stimulation, i.e. eNOS is in an inactive state. As in the endothelial cell, NO deficiency in PAH hearts is associated with greater HIF-activation and increased glycolytic metabolism as identified by glycolytic enzyme expression and uptake of the glucose analogue [18F]2-fluoro-2-deoxy-D-glucose by positron emission tomography (fasting FDG-PET) in PAH patients. Exciting preliminary studies indicate that b-blockers reverse ?AR dysfunction, restore phosphatase- mediated eNOS activation, and thus increase cAMP and NO production, respectively. Thus, we hypothesize that cardiomyocytes and endothelial cells in PAH suffer from interconnected abnormalities of ?AR function and eNOS activation that lead to a HIF-mediated maladaptive vascular and cardiomyocyte phenotype, all of which is reversible by ?-blocker. We test this hypothesis PAEC derived from patients' lungs, explanted human hearts, and in a mechanistic longitudinal study of ?AR blockade in PAH patients.

描述（由申请方提供）：肺动脉高压（PAH）是一种致死性疾病，其特征为肺血流动力学和血管生长调节受损;右心室衰竭是死亡的主要原因。我们的研究已经确定了PAH患者肺血管内皮一氧化氮合酶（eNOS）活性的丧失，并且NO缺乏导致缺氧诱导因子-1（HIF-1）激活，这导致糖酵解、增殖、抗凋亡内皮细胞促进血管重塑。eNOS活性丧失的机制尚不清楚。eNOS也存在于心肌细胞中，其中eNOS的NO合成具有心脏保护作用;但尚未在人类PAH心脏中研究eNOS。eNOS的激活需要在Three 495（T495）处的酶去磷酸化和在丝氨酸1177（S1177）处的磷酸化，后者由环磷酸腺苷（cAMP）/蛋白激酶途径介导。肾上腺素能受体（？AR）[图1]。为什么？我们研究发现，在所有心力衰竭患者中均存在AR下调和脱敏现象？AR在eNOS活性丧失及其对肺血管-右心室（RV）轴的后果。移植的人PAH心脏有脱敏和低数量的？AR，并为第一次，我们表明，肺动脉内皮细胞（PAEC）从人类肺PAH肺有类似的低数量和脱敏？AR.初步数据显示，？AR脱敏是由于磷酸酶对受体的去磷酸化不足，而磷酸酶被磷脂酰肌醇3-激酶（PI 3 Kg）的过度活化所抑制。?由于磷酸化受体的细胞内再循环缺陷，AR数量较低。与磷酸酶的PI 3 K抑制一致，PAH PAEC和心肌细胞具有高水平的无活性pT 495 eNOS，确定了任何类型的激动剂刺激后NO产生减少的原因，即eNOS处于无活性状态。与内皮细胞一样，PAH心脏中的NO缺乏与更大的HIF激活和糖酵解代谢增加相关，如通过PAH患者中糖酵解酶表达和葡萄糖类似物[18 F]2-氟-2-脱氧-D-葡萄糖的摄取（通过正电子发射断层扫描（空腹FDG-PET）确定）。令人兴奋的初步研究表明，b受体阻滞剂逆转？AR功能障碍，恢复磷酸酶介导的eNOS激活，从而分别增加cAMP和NO的产生。因此，我们假设，心肌细胞和内皮细胞在肺动脉高压遭受相互关联的异常？AR功能和eNOS激活导致HIF介导的适应不良的血管和心肌细胞表型，所有这些都是可逆的？修颜乳液我们测试这一假设PAEC来自患者的肺，心脏，并在一个机械纵向研究？PAH患者中的AR阻断。