Protein Kinase A Inhibitor Peptide (PKI) and Cardiac Protection in Heart Failure

蛋白激酶 A 抑制肽 (PKI) 与心力衰竭的心脏保护

• 批准号: 8860229
• 负责人: Xiongwen Chen
• 金额: $ 38.42万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8860229
• 关键词: Adenylate Cyclase; Adrenergic Agents; Adrenergic Receptor; Adrenergic beta-Antagonists; Amino Acids; Animal Model; Apoptosis; Arrhythmia; Base Sequence; Binding; Blood; CREB1 gene; Calmodulin; Cardiac; Catecholamines; Cause of Death; Cell Death; Chronic; Complex; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Defect; Development; Disadvantaged; Fibrosis; Functional disorder; Gene Delivery; Gene Dosage; Gene Expression; Genes; Goals; Health; Heart; Heart failure; Hypertrophy; Knock-out; Knockout Mice; Ligation; Measures; Mediating; Metabolism; Metoprolol; Mus; Muscle Cells; Myocardial Infarction; Myocardium; Nodal; Normal tissue morphology; PKA inhibitor; Pathway interactions; Patients; Peptides; Phosphotransferases; Protein Deficiency; Protein Isoforms; Protein Kinase A Inhibitor; Proteins; Pump; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Stress; Structure; Syndrome; System; Testing; Transgenic Animals; Transgenic Mice; adrenergic; fusion gene; gene therapy; genetic manipulation; heart function; improved; novel; overexpression; protective effect; research study; response; tool; viral gene delivery

DESCRIPTION (provided by applicant): Myocardial infarction (MI) is a major cause of HF. MI requires persistent activation of the sympathetic adrenergic system (SAS) in order to maintain the pump function of the heart. SAS activation causes excessive activation of protein Kinase A (PKA) and Ca2+/calmodulin-dependent kinase II (CaMK II), which causes adverse cardiac remodeling and promotes HF development. Thus, limiting excessive PKA activity could have beneficial effects in hearts after MI. There are endogenous PKA inhibitor proteins (PKI) in the heart that may regulate PKA activity. However, the role of PKI in normal and diseased hearts remains unclear. We have found that the endogenous PKIa is upregulated in mouse hearts after MI and PKIa deficiency enhances cardiac adrenergic responses but precipitates HF development after MI. beta-AR stimulation also activates PKA- independent cardioprotective signaling pathways because: (1) PKA inhibition spares cAMP signaling to EPAC/Rap1/Raf/ERK pathway to protect cultured myocytes from apoptosis~ (2) PKI-GFP transgenic mice had improved cardiac function and reduced hypertrophy than control mice after MI. (3) Metoprolol, a beta-blocker may reduce some of beneficial effects of PKI in post-MI hearts. In this study we will determine if and how KI regulates adrenergic signaling in the normal and infarcted heart. We hypothesize that PKI-mediated inhibition of excessive PKA activation in stressed hearts will reduce the potentially detrimental effects of PKA and CaMK II signaling and will preserve beneficial effects f SAS signaling through cAMP/EPAC and b2AR/Gi/Akt pathways. Our hypothesis is that PKA is an essential nodal control point for the detrimental effects of excessive SAS activity i cardiac stress states. We predict that clinically effective bAR antagonists used to tret HF patients will probably reduce both detrimental and cardioprotective features of bAR signaling. Therefore, a selective PKA inhibitory approach through PKI will mimics an "optimized" biased beta-blocker, which may provide more benefit than commonly used beta-blocker therapies. To test these ideas, we have established a PKIa knockout mouse line, and transgenic mouse lines overexpressing different levels (high, medium and low) of a PKI-GFP fusion gene. To explore the role of EPAC activation in cardiac protection spared by PKA inhibition after MI, we will use mice deficient in EPAC1 or EPAC2. Our SPECIFIC AIMS are: 1. To determine the role of endogenous PKA inhibition by PKI in HF development after MI. PKI-a knockout and control mice will be stressed with MI. 2. To determine if and how selective inhibition of PKA, with overexpression of a PKI minigene (either by genetic manipulation or alternatively by viral gene delivery), can reduce MI-induced structural and functional changes that cause HF. We will also compare the protective effects of PKA inhibition with PKI to those of beta-blockers. Our long-term goal is to reveal the roles of PKA/PKI in HF and explore the possibility of using PKI to treat HF.

描述（由申请人提供）：心肌梗塞（MI）是HF的主要原因。 MI需要持续激活交感神经肾上腺素能系统（SAS），以维持心脏的泵功能。 SAS激活会导致蛋白激酶A（PKA）和Ca2+/钙调蛋白依赖性激酶II（CAMK II）的过度激活，这会导致心脏不良重塑并促进HF的发展。因此，限制过多的PKA活性可能在MI之后对心脏产生有益的影响。心脏中有内源性PKA抑制剂蛋白（PKI）可能调节PKA活性。但是，PKI在正常和患病心脏中的作用尚不清楚。我们发现，MI和PKIA缺乏后，内源性PKIA在小鼠心脏中被上调，增强了心脏肾上腺素能反应，但在MI后会沉淀HF发育。 β-AR刺激还激活了PKA-独立的心脏保护信号传导途径，因为：（1）PKA抑制在camp camp信号传导到EPAC/RAP1/RAP1/RAP1/RAIF/ERK途径以保护培养的肌细胞免受凋亡的影响〜（2）PKI-GFP转基因小鼠的心脏功能和对照小鼠的过度症比MI改善了心脏功能和对照小鼠的改善。 （3）美托洛尔，β受体阻滞剂可能会减少PKI在MI后心脏中的某些有益作用。 在这项研究中，我们将确定KI是否以及如何调节正常和梗塞心脏中的肾上腺素能信号传导。我们假设PKI介导的压力心脏中PKA过度激活的抑制作用将减少PKA和CAMK II信号的潜在有害作用，并将通过CAMP/EPAC/EPAC和B2AR/GI/AKT途径保留有益的效果F SAS信号。我们的假设是，PKA是SAS活性I心脏应激状态的有害影响的重要淋巴结控制点。 我们预测，用于HF HF患者的临床有效的酒吧拮抗剂可能会减少条形信号的有害和心脏保护特征。 因此，通过PKI进行选择性的PKA抑制方法将模仿“优化”的偏置β受体阻滞剂，该β受体阻滞剂可能比常用的β受体阻滞剂疗法更具好处。为了测试这些想法，我们已经建立了PKIA基因敲除小鼠系，而转基因小鼠线过表达PKI-GFP融合基因的不同水平（高，中和低）。为了探索EPAC激活在MI后PKA抑制保留的心脏保护中的作用，我们将使用缺乏EPAC1或EPAC2的小鼠。我们的具体目的是：1。确定PKI在MI后PKI抑制内源性PKA的作用。 PKI-A敲除和对照小鼠将用MI强调。 2。确定PKA的选择性抑制以及如何通过过度表达PKI Minigene（通过遗传操作或通过病毒基因传递）可以减少导致HF的MI诱导的结构和功能变化。我们还将将PKA抑制作用与PKI与β受体阻滞剂的保护作用进行比较。 我们的长期目标是揭示PKA/PKI在HF中的作用，并探索使用PKI治疗HF的可能性。