Pulmonary Vascular-Right Ventricular Axis Research Program

肺血管-右心室轴研究计划

• 批准号: 8355145
• 负责人: Serpil C. Erzurum
• 金额: $ 67.32万
• 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/8355145
• 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. PUBLIC HEALTH RELEVANCE: Pulmonary arterial hypertension (PAH) is a fatal disease associated with increased pulmonary artery pressure and abnormalities in blood vessel growth. Heart failure is the primary cause of death, but current therapies focus entirely on treating the pulmonary hypertension. The determinants of heart failure are unknown. Some patients have adaptive responses of the heart and retain good function for years, while others have progressive heart failure. The goal of this study is to discover the fundamental mechanisms underlying the development and progression of heart failure so that we can use the knowledge to develop successful strategies for comprehensive treatment of the pulmonary hypertension and heart failure.

描述（由申请人提供）：肺动脉高压（PAH）是一种致命的疾病，其特征是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。我们的研究发现，PAH 中肺血管内皮一氧化氮合酶 (eNOS) 活性丧失，NO 缺乏会导致缺氧诱导因子 1 (HIF-1) 激活，从而导致糖酵解、增殖、抗凋亡内皮细胞促进血管重塑的细胞。 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 合成的 NO 具有心脏保护作用；但 eNOS 尚未在人类 PAH 心脏中进行研究。 eNOS 的激活需要苏氨酸 495 (T495) 处的酶去磷酸化和丝氨酸 1177 (S1177) 处的磷酸化，后者由 β-肾上腺素能受体 (?AR) 下游的环腺苷 (cAMP)/蛋白激酶途径介导 [图 1]。由于所有心力衰竭中都存在 βAR 下调和脱敏，因此我们研究了 eNOS 活性丧失中的 βAR 及其对肺血管-右心室 (RV) 轴的影响。移植的人 PAH 心脏具有脱敏和低数量的 ?AR，并且我们首次表明，来自人 PAH 肺部的肺动脉内皮细胞 (PAEC) 具有类似的低数量和脱敏的 ?AR。初步数据显示，αAR 脱敏是由于磷酸酶对受体的去磷酸化不足所致，磷酸酶受到磷脂酰肌醇 3-激酶 (PI3Kg) 过度激活的抑制。 ?由于磷酸化受体的细胞内循环缺陷，AR 数量较低。与磷酸酶的 PI3K 抑制一致，PAH PAEC 和心肌细胞具有高水平的非活性 pT495 eNOS，确定了在任何类型的激动剂刺激下 NO 产生减少的原因，即 eNOS 处于非活性状态。与内皮细胞一样，PAH 心脏中的 NO 缺乏与 HIF 激活增强和糖酵解代谢增加有关，如糖酵解酶表达和正电子对葡萄糖类似物 [18F]2-氟-2-脱氧-D-葡萄糖的摄取所确定的那样。 PAH 患者的发射断层扫描（空腹 FDG-PET）。令人兴奋的初步研究表明，β-受体阻滞剂可逆转 αAR 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 PAH 中的心肌细胞和内皮细胞遭受 αAR 功能和 eNOS 激活的相互关联的异常，导致 HIF 介导的血管和心肌细胞适应不良表型，所有这些都可以通过 α-受体阻滞剂逆转。我们测试了这一假设，PAEC 源自患者的肺部、移植的人类心脏，并在 PAH 患者中进行了 ?AR 阻断的机制纵向研究。 公共卫生相关性：肺动脉高压 (PAH) 是一种与肺动脉压力升高和血管生长异常相关的致命疾病。心力衰竭是死亡的主要原因，但目前的治疗完全集中于治疗肺动脉高压。心力衰竭的决定因素尚不清楚。一些患者具有心脏的适应性反应并保持良好的功能多年，而另一些患者则患有进行性心力衰竭。本研究的目的是发现心力衰竭发生和进展的基本机制，以便我们能够利用这些知识制定成功的策略来综合治疗肺动脉高压和心力衰竭。