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

• 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
• 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

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：心脏病是美国人的主要死因。？-肾上腺素能受体(？-AR)兴奋是增加心肌收缩能力的主要机制。然而，慢性交感神经刺激，如在心力衰竭(HF)中发生的，导致受体脱敏和收缩能力降低。？-AR刺激信号通过依赖于PKA的磷酸化，部分通过PKA与A-激酶锚定蛋白(AKAP)的结合来影响钙稳态。AKAP针对特定的细胞内位置，导致PKA及其底物的定位。因此，修改PKA信号的药物有望调节增强的变力反应。基于在心肌细胞中观察到：(A)腺病毒(Ad)介导的Ht31表达，一种竞争调节的PKA亚单位(RLL)结合肽，破坏了与AKAP结合的PKA，从而增加了对？-AR刺激的收缩反应，并且(B)令人惊讶的是，这种情况在没有增加的钙瞬变的情况下发生。我们急于验证这个项目的中心假设，即在活体心脏中破坏PKA与AKAPs的结合，增强正常心脏对？-AR刺激的收缩反应，并挽救受损的收缩反应，这是一种心衰模型。我认为这种肌力反应的增加部分是通过增加肌丝对钙的敏感性来实现的。我们的目标是了解AKAP的功能以及这种多组分的PKA信号调节因子在健康和心血管疾病中的信号转导。通过利用Ad介导的Ht31肽通过大鼠心脏体内基因转移来阻断PKA/AKAP相互作用，我们将评估正常和衰竭大鼠心脏的收缩能力和心肌重塑是否都增加(目标1)；以及介导收缩能力改变的事件是否源于PKA依赖的磷酸化减少导致肌丝钙敏感性增加(目标2)。通过使用Gravin(AKAP12)基因敲除小鼠来特异性地靶向并干扰PKA对β2-AR的定位，我们将确定在体内是否通过阻断AKAP12调节的受体脱敏来增强心功能，类似于在？ARKct恢复心功能的能力(目标3)；以及使用这些小鼠的心脏和心肌细胞(目标4)，？-AR刺激后的心功能增强是否是通过增加？2-AR依赖的中介信号来调节的(目标4)。我们的目标的实现，不仅应该提高我们对这个PKA信号中枢调节因子的功能和信号转导的理解，而且可能成为心力衰竭患者变力治疗的新靶点。