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）是心力衰竭的主要原因。 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+/钙调蛋白依赖性激酶 II (CaMK II) 过度激活，从而导致不良心脏重塑并促进心力衰竭的发生。因此，限制过度的 PKA 活性可能对 MI 后的心脏产生有益的影响。心脏中存在内源性 PKA 抑制蛋白 (PKI)，可以调节 PKA 活性。然而，PKI 在正常和患病心脏中的作用仍不清楚。我们发现 MI 后小鼠心脏中的内源性 PKIa 上调，并且 PKIa 缺乏会增强心脏肾上腺素能反应，但会在 MI 后加速心力衰竭的发生。 beta-AR 刺激还激活 PKA 独立的心脏保护信号通路，因为：(1) PKA 抑制使 cAMP 信号转导至 EPAC/Rap1/Raf/ERK 通路，从而保护培养的心肌细胞免于凋亡~(2) PKI-GFP 转基因小鼠的心脏功能得到改善与 MI 后的对照小鼠相比，肥厚减少。 (3) 美托洛尔（一种 β 受体阻滞剂）可能会降低 PKI 对 MI 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塞心脏中的肾上腺素能信号传导。我们假设 PKI 介导的对应激心脏中过度 PKA 激活的抑制将减少 PKA 和 CaMK II 信号传导的潜在有害影响，并通过 cAMP/EPAC 和 b2AR/Gi/Akt 途径保留 SAS 信号传导的有益影响。我们的假设是，PKA 是心脏应激状态下 SAS 过度活动产生有害影响的重要节点控制点。 我们预测，用于治疗心力衰竭患者的临床有效的 bAR 拮抗剂可能会减少 bAR 信号传导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”的偏向 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益处。为了测试这些想法，我们建立了 PKIa 敲除小鼠品系，以及过表达不同水平（高、中和低）PKI-GFP 融合基因的转基因小鼠品系。为了探讨 EPAC 激活在心肌梗死后免受 PKA 抑制的心脏保护中的作用，我们将使用 EPAC1 或 EPAC2 缺陷的小鼠。我们的具体目标是： 1. 确定 PKI 抑制内源性 PKA 在 MI 后心力衰竭发展中的作用。 PKI-a 敲除小鼠和对照小鼠将承受 MI 应激。 2. 确定选择性抑制 PKA 并过度表达 PKI 小基因（通过基因操作或通过病毒基因传递）是否以及如何能够减少 MI 诱导的导致心力衰竭的结构和功能变化。我们还将比较 PKI 抑制 PKA 与 β 受体阻滞剂的保护作用。 我们的长期目标是揭示PKA/PKI在心力衰竭中的作用，并探索使用PKI治疗心力衰竭的可能性。