Ang II and Norepinephrine in Cardiac Sympathetic Nerves

心脏交感神经中的 Ang II 和去甲肾上腺素

• 批准号: 7177556
• 负责人: ROBERTO LEVI
• 金额: $ 47.79万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7177556
• 关键词: 1-Methyl-4-phenylpyridinium; 6-carboxyfluorescein; ANG gene; Abbreviations; Acute; Address; Amiloride; Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Arrhythmia; Biological; Buffers; Calcium; Calmodulin; Cardiac; Cavia; Cell Degranulation; Cell Line; Cell model; Cells; Cessation of life; Chemosensitization; Coupling; Cultured Cells; Data; Desipramine; Elements; Enzymes; Esters; Exocytosis; Exposure to; Figs - dietary; Functional disorder; Grant; Heart; Human; Incubated; Investigation; Ischemia; Kidney; Knock-out; Knockout Mice; Measures; Mediating; Membrane; Modeling; Molecular; Mus; Myocardial Ischemia; Nerve; Nerve Endings; Neuroblastoma; Neurons; Norepinephrine; Parents; Pathologic; Pathway interactions; Peptidyl-Dipeptidase A; Physiological; Physiological reperfusion; Physiology; Play; Proto-Oncogene Protein c-kit; Rate; Rattus; Receptor, Angiotensin, Type 1; Renin; Renin-Angiotensin System; Reperfusion Therapy; Research Personnel; Role; Signal Pathway; Signal Transduction; Source; Synaptosomes; Ventricular Fibrillation; Work; angiogenin; base; congenic; mast cell; noradrenaline transporter; novel; paracrine; prevent; programs; receptor; research study; response; therapeutic target

DESCRIPTION (provided by applicant): In myocardial ischemia, pathologic release of norepinephrine (NE) from sympathetic nerves leads to arrhythmias and death. The mechanisms responsible remain obscure. The overall objective of this grant is to address the important biological issue of whether a local renin-angiotensin system (RAS) plays a significant role in exacerbating NE release in myocardial ischemia. Our preliminary results demonstrate that cardiac mast cells are a novel source of renin, the rate-limiting enzyme responsible for initiating ANG n formation. We hypothesize that degranulation of cardiac mast cells, as occurs in ischemia, is pivotal for activation of local RAS and ANG II formation in the proximity of neuronal ATi receptors (ATiR). In Specific Aim I, we will characterize mast-cell renin from congenic controls (CC) of c-Kit knock out (KO) mice, and from cultured human mast cells (HMC-1). We will also investigate in normoxic and ischemic cardiac models from guinea-pigs, and CC and KO mice, whether locally synthesized ANG n from mast-cell-derived renin activates neuronal ATiR to elicit NE release and reperfusion arrhythmias. We have already ascertained in a cultured-cell model of ischemic sympathetic nerves, that exogenous ANG n stimulates neuronal Na+/H^ exchange (NHE) leading to excessive carrier-mediated NE release. Thus, in Specific Aim n we will study, in human neuroblastoma cells transfected with the cloned rat ATjA receptor (SH-SYSY-ATu), the signal transduction of this ANG H-mediated NHE stimulation. Experiments in SH-SYSY-ATiA cells demonstrate that stimulation of NHE and carrier-mediated NE release by AT)R activation occurs via a Ca +-dependent pathway. Accordingly, our investigation will focus on elucidating the role of PLC, Ca2+, PKC, and calmodulin in this Ca2+-dependent pathway. The overall premise of these experiments is that if we understand the patho-physiological basis for the formation of ANG n in the ischemic heart, and how ANG II exacerbates NE release, then we will also have identified potential therapeutic targets to alleviate ischemic arrhythmias and associated cardiac dysfunctions.

描述(申请人提供)：在心肌缺血时，交感神经病理性释放去甲肾上腺素(NE)导致心律失常和死亡。负责的机制仍然不清楚。这笔赠款的总体目标是解决重要的生物学问题，即局部肾素-血管紧张素系统(RAS)在心肌缺血时是否在加剧NE释放方面发挥重要作用。我们的初步结果表明，心脏肥大细胞是肾素的新来源，肾素是启动血管紧张素形成的限速酶。我们假设，心肌肥大细胞的脱颗粒，就像在缺血时发生的那样，对于激活局部RAS和神经元ATI受体(ATI)附近的Ang II形成是关键的。在特定的目标I中，我们将从c-Kit基因敲除(KO)小鼠的同源对照(CC)和培养的人类肥大细胞(HMC-1)中鉴定肥大细胞肾素。我们还将在豚鼠、CC和KO小鼠的常氧和缺血心脏模型上，研究肥大细胞来源的肾素局部合成的Ang是否激活神经元Atir，从而引发NE释放和再灌注性心律失常。我们已经在缺血型交感神经培养细胞模型中证实，外源性Ang_n刺激神经元Na~+/H~+交换(NHE)，导致载体介导的NE过度释放。因此，有针对性地，我们将在转导克隆的大鼠ATjA受体的人神经母细胞瘤细胞(SH-SYSY-ATU)中，研究这种Ang H介导的NHE刺激的信号转导。在SH-SYSY-ATIA细胞中的实验表明，AT)R激活对NHE和载体介导的NE释放的刺激是通过钙依赖的途径发生的。因此，我们的研究将集中于阐明PLC、Ca~(2+)、PKC和钙调蛋白在这一钙依赖途径中的作用。这些实验的总体前提是，如果我们了解缺血心脏血管紧张素Ⅱ形成的病理生理学基础，以及血管紧张素Ⅱ是如何促进去甲肾上腺素释放的，那么我们也将确定潜在的治疗靶点来缓解缺血性心律失常和相关的心功能障碍。