Targeted Disruption of Beta-Adrenergic Signaling to Increase Cardiac Contractilit

有针对性地破坏 β-肾上腺素能信号以增加心脏收缩力

基本信息

批准号：
7841125
负责人：
BRADLEY K MCCONNELL
金额：
$ 26.09万
依托单位：
UNIVERSITY OF HOUSTON
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-15 至 2012-07-14
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7841125
关键词：
A kinase anchoring protein AKAP12 gene AKAP13 gene Achievement Acute Adenoviruses Adrenergic Agents Adrenergic Receptor Adverse effects Agonist Apoptosis Arrhythmia Back Binding Binding Sites CREB1 gene Calcium Calcium Signaling Cardiac Cardiac Myocytes Cardiomyopathies Cardiovascular Diseases Caspase Catheterization Cause of Death Cell physiology Cells Chronic Clinical Complex Congenital Heart Defects Coronary Arteriosclerosis Cyclic AMP Cyclic AMP-Dependent Protein Kinases Development Diagnosis Dimensions Disease Dobutamine Dose Echocardiography Evaluation Event Functional disorder Gene Expression Gene Expression Microarray Analysis Gene Transfer Goals Gravin Health Heart Heart Diseases Heart failure Homeostasis Human Hypertension Image Impairment Infusion procedures Isoproterenol Knock-out Knockout Mice Lead Left Ventricular Ejection Fraction Location Measures Mediating Microfilaments Milrinone Modeling Morphology Mus Muscle Cells Myocardial Myocardial Infarction Myocarditis Patients Peptides Phosphodiesterase Inhibitors Phosphorylation Principal Investigator Public Health Publishing Rattus Regulation Relaxation Research Research Personnel RyR2 Ryanodine Receptor Calcium Release Channel Ryanodine Receptors Signal Pathway Signal Transduction Syndrome Tachycardia Testing Thyroid Diseases Tissues Troponin I United States Ventricular Ventricular Arrhythmia Ventricular Remodeling adenoviral-mediated adenylyl cyclase 2 adrenergic base blood pump density depressed desensitization falls genetic regulatory protein hemodynamics improved in vivo indexing inhibitor/antagonist mouse model myosin-binding protein C new therapeutic target novel papillary muscle phospholamban pressure programs protein function receptor response therapeutic target

项目摘要

DESCRIPTION: Heart disease is the leading cause of death in the USA. ?-adrenergic receptor (?-AR) stimulation is the primary mechanism to increase cardiac contractility. However chronic sympathetic stimulation, as occurs in heart failure (HF), results in receptor desensitization and reduced contractility. ?-AR stimulation signals through PKA-dependent phosphorylation in part by PKA binding to A-kinase anchoring proteins (AKAPs) to influence Ca2+ homeostasis. AKAPs are targeted to specific intracellular locations resulting in localization of PKA with its substrates. Thus agents that modify PKA signaling would be expected to mediate an enhanced inotropic response. Based on observations in myocytes that (a) adenoviral (Ad) mediated Ht31 expression, a competing regulatory PKA subunit (Rll) binding peptide, disrupted PKA anchoring to AKAPs which increased the contractile response to ?-AR stimulation and this (b) surprisingly occurred in the absence of increased Ca2+ transients. We are eager to test the central hypothesis of this project that disruption of PKA binding to AKAPs in hearts in vivo, enhances the contractile response to ?-AR stimulation in normal hearts and rescues the impaired contractile response a model of HF. I propose that this increased inotropic response is mediated in part by increasing myofilament Ca2+ sensitivity. Our goal is to understand AKAP function and the signal transduction of this multi-component regulator of PKA signaling in health and in cardiovascular disease. By using Ad-mediated Ht31 peptide expression via in vivo gene transfer of rat hearts to disrupt PKA/AKAP interactions, we will evaluate whether cardiac contractility and myocardial remodeling are increased in both normal and failing rat hearts (Aim 1); and whether the events mediating altered contractility results from decreased PKA-dependent phosphorylation leading to increased myofilament Ca2+ sensitivity (Aim 2). By using gravin (AKAP12) knockout mice to specifically target and disrupt PKA localization to the ?2- AR, we will determine whether cardiac function in vivo, is increased by blocking AKAP12 regulated receptor desensitization, similar to that observed with ?ARKct's ability to restore cardiac function in HF (Aim 3); and whether increased cardiac function following ?-AR stimulation is mediated by increased ?2-AR dependent mediated signaling, using hearts and myocytes from these mice (Aim 4). Achievement of our aims, should not only improve our understanding of the function and signal transduction for this central regulator of PKA signaling, but may potentially represent a novel therapeutic target for inotropic therapy for patients with HF.

描述：心脏病是美国的首要死因。 β-肾上腺素能受体（β-AR）刺激是增加心肌收缩力的主要机制。然而，慢性交感神经刺激，如心力衰竭 (HF) 中发生的情况，会导致受体脱敏和收缩力降低。 β-AR 刺激信号通过 PKA 依赖性磷酸化部分通过 PKA 与 A 激酶锚定蛋白 (AKAP) 结合来影响 Ca2+ 稳态。 AKAP 靶向特定的细胞内位置，导致 PKA 及其底物定位。因此，修饰 PKA 信号传导的药物有望介导增强的正性肌力反应。基于对肌细胞的观察，(a) 腺病毒 (Ad) 介导 Ht31 表达，一种竞争性调节 PKA 亚基 (RII) 结合肽，破坏了 PKA 锚定到 AKAP，从而增加了对 α-AR 刺激的收缩反应，并且 (b) 令人惊讶地发生了在没有增加 Ca2+ 瞬变的情况下。我们渴望测试这个项目的中心假设，即破坏体内PKA与AKAPs的结合，增强正常心脏对β-AR刺激的收缩反应，并挽救心力衰竭模型中受损的收缩反应。我认为这种增强的正性肌力反应部分是通过增加肌丝 Ca2+ 敏感性来介导的。我们的目标是了解 AKAP 功能以及这种 PKA 信号多组分调节剂在健康和心血管疾病中的信号转导。通过利用 Ad 介导的 Ht31 肽表达，通过大鼠心脏的体内基因转移来破坏 PKA/AKAP 相互作用，我们将评估正常和衰竭大鼠心脏的心肌收缩力和心肌重塑是否增加（目标 1）；介导收缩性改变的事件是否是由 PKA 依赖性磷酸化减少导致肌丝 Ca2+ 敏感性增加所致（目标 2）。通过使用 gravin (AKAP12) 敲除小鼠特异性靶向和破坏 PKA 定位到 ?2-AR，我们将确定是否通过阻断 AKAP12 调节的受体脱敏来增强体内心脏功能，类似于用 ?ARKct 恢复能力观察到的结果心力衰竭时的心脏功能（目标 3）；以及使用这些小鼠的心脏和肌细胞，α-AR 刺激后心脏功能的增强是否是通过增强的 β2-AR 依赖性介导的信号传导来介导的（目标 4）。我们目标的实现，不仅应该提高我们对 PKA 信号传导中央调节器的功能和信号转导的理解，而且可能成为心力衰竭患者正性肌力治疗的新治疗靶点。