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: 8580498
• 负责人: Xiongwen Chen
• 金额: $ 36.89万
• 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 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8580498
• 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; 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; public health relevance; 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）：心肌梗死（MI）是心衰的主要原因。心肌梗死需要持续激活交感肾上腺素能系统（SAS）以维持心脏的泵功能。SAS激活导致蛋白激酶A （PKA）和Ca2+/钙调素依赖性激酶II （CaMK II）过度激活，导致不良的心脏重构并促进HF的发展。因此，限制过度的PKA活性可能对心肌梗死后的心脏有有益的影响。心脏中有内源性PKA抑制剂蛋白（PKI）可以调节PKA活性。然而，PKI在正常和病变心脏中的作用尚不清楚。我们发现小鼠心肌梗死后内源性PKIa上调，PKIa缺乏增强心脏肾上腺素能反应，但促进心肌梗死后HF的发展。β - ar刺激也激活不依赖于PKA的心脏保护信号通路，因为：(1) PKA抑制抑制cAMP信号通路EPAC/Rap1/Raf/ERK通路，保护培养的心肌细胞凋亡~(2)与对照组相比，PKI- gfp转基因小鼠心肌梗死后心功能改善，肥厚减轻。(3)β受体阻滞剂美托洛尔可能降低PKI对心肌梗死后心脏的一些有益作用。在这项研究中，我们将确定KI是否以及如何调节正常和梗死心脏的肾上腺素能信号。我们假设，在应激心脏中，通过pki介导的过度PKA激活的抑制将减少PKA和CaMK II信号的潜在有害影响，并将通过cAMP/EPAC和b2AR/Gi/Akt途径保持SAS信号的有益作用。我们的假设是PKA是心脏应激状态下过度SAS活性有害影响的重要节点控制点。我们预测用于治疗HF患者的临床有效的bAR拮抗剂可能会减少bAR信号的有害和心脏保护功能。因此，通过PKI的选择性PKA抑制方法将模仿“优化的”偏倚β受体阻滞剂，这可能比常用的β受体阻滞剂疗法提供更多的益处。为了验证这些想法，我们建立了PKIa敲除小鼠系和过表达不同水平（高、中、低）PKI-GFP融合基因的转基因小鼠系。为了探索EPAC激活在心肌梗死后PKA抑制所保留的心脏保护中的作用，我们将使用EPAC1或EPAC2缺失的小鼠。我们的具体目标是：1。为了确定内源性PKI抑制PKA在心肌梗死后HF发展中的作用，将PKI-a敲除小鼠和对照组小鼠进行心肌梗死应激。为了确定是否以及如何选择性抑制PKA，通过PKI小基因的过表达（无论是通过遗传操作还是通过病毒基因传递），可以减少mi诱导的导致HF的结构和功能变化。我们还将比较PKI对PKA抑制的保护作用与β受体阻滞剂的保护作用。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。