HERB-INDUCED OXIDANT PRECONDITIONING IN CARDIOMYOCYTES

草药诱导的心肌细胞氧化预处理

• 批准号: 7470953
• 负责人: Zuo-hui Shao
• 金额: $ 23.4万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7470953
• 关键词: Alternative Medicine; Antioxidants; Apoptosis; Apoptotic; Attenuated; Cardiac; Cardiac Myocytes; Caspase; Cell Death; Cell Survival; Cells; Cessation of life; Clinical; DNA Fragmentation; Dose; Electron Transport; Event; Exposure to; Figs - dietary; Flavonoids; Future; Gene Silencing; Generations; Heart; Heart Arrest; Herb; Herbal Medicine; Hypoxia; Injury; Ischemia; Ischemic Preconditioning; Knock-out; Knockout Mice; Lactate Dehydrogenase; Lead; Measures; Mediating; Mediator of activation protein; Medicine; Membrane Potentials; Mitochondria; Modeling; Mus; Myocardial Infarction; Nitric Oxide; Oxidants; Pathway interactions; Patients; Phase; Phenotype; Phosphorylation; Phosphotransferases; Production; Property; Protocols documentation; Reactive Oxygen Species; Reperfusion Injury; Reperfusion Therapy; Risk; Role; Scutellaria baicalensis; Signal Pathway; Signal Transduction; Simulate; Small Interfering RNA; Source; Stress; Testing; Time; Work; attenuation; baicalein; cytochrome c; design; genetic manipulation; inhibitor/antagonist; kinase inhibitor; mimetics; mitochondrial membrane; mouse model; oxidant stress; preconditioning; prevent; protective effect; public health relevance; research study; response; translational study

DESCRIPTION (provided by applicant): This proposal builds upon work suggesting that the herbal extract Scutellaria baicalensis (SbE) and its major component baicalein may simulate many important components of cardiac preconditioning (PC), i.e. trigger transient mitochondrial oxidant signaling, activate the survival kinase Akt, attenuate reperfusion reactive oxygen species (ROS) and increase reperfusion nitric oxide (NO) generation. It is one of the few PC compounds we have tested that provides significant protection in 3 lethal models of cardiac ischemia/ reperfusion (I/R): chick cardiomyocytes, murine cardiomyocytes and murine cardiac arrest. An herbal extract already used in popular alternative medicine has practical advantages for use as a pharmacologic cardiac PC agent in patients at risk for adverse cardiac events. This proposal seeks to further examine PC protection induced by SbE and/or baicalein in murine cardiomyocytes by determining the mechanisms involved in generating the protective phenotype. We hypothesize that SbE and/or baicalein will induce PC protection against murine cardiomyocyte I/R injury via a transient ROS generation that initiates the activation of PKCe and/or Akt resulting in eNOS activation and increased reperfusion NO generation. Specifically, Aim 1 will optimize the dose of SbE and/or baicalein that trigger ROS-mediated PC, and determine the source and importance of these ROS using various antioxidants and mitochondrial inhibitors. Further, we will test whether these transient ROS induce augmented reperfusion NO and protection against apoptosis. In Aim 2, we will evaluate the pathway by which the most effective herb-induced PC protocol confers protection. We will assess the activation of PKCe and/or Akt in herb-induced PC using PKCe translocation, Akt phosphorylation, and Akt activity. We also will examine the role of ROS in inducing PKCe and/or Akt activation and the effect of this kinase activation on eNOS phosphorylation and NO generation using kinase inhibitors, siRNA gene silencing and knockout strategies for eNOS and Akt-1. These results will help clarify important PC pathways in murine cardiomyocytes, focusing on how mitochondrial oxidants, certain stress kinases, and eNOS may interact to protect against I/R injury. This work will be used to plan translational studies of herb-PC into our mouse model of cardiac arrest. Finally, a better understanding of SbE- and/or baicalein PC could lead to new oxidant-mediated PC clinical therapies. PUBLIC HEALTH RELEVANCE: From a layperson perspective, there are few medicines that protect against future heart attacks. In addition, many studies of herb compounds as alternative medicines have focused on their antioxidant effects. This proposal will study an herb mixture that actually increases a type of oxidant stress in the heart that may help condition it and protect against future heart attack injury.

DESCRIPTION (provided by applicant): This proposal builds upon work suggesting that the herbal extract Scutellaria baicalensis (SbE) and its major component baicalein may simulate many important components of cardiac preconditioning (PC), i.e. trigger transient mitochondrial oxidant signaling, activate the survival kinase Akt, attenuate reperfusion reactive oxygen species (ROS) and increase reperfusion一氧化氮（NO）产生。这是我们测试过的少数PC化合物之一，可在3种致命的心脏缺血/再灌注模型（I/ R）中提供明显的保护：鸡心肌细胞，鼠心肌细胞和鼠心脏骤停。在流行替代医学中已经使用的草药提取物在患有不良心脏事件风险的患者中用作药理学心脏PC剂具有实际优势。该提案旨在通过确定产生保护性表型的机制来进一步检查鼠心肌细胞中SBE和/或黄氨酸引起的PC保护。我们假设SBE和/或黄胶蛋白会通过瞬时ROS产生诱导PC防御鼠心肌细胞I/R损伤，从而启动PKCE和/或Akt的激活，从而导致eNOS激活，并增加再灌注。具体而言，AIM 1将优化触发ROS介导的PC的SBE和/或黄酸酯的剂量，并使用各种抗氧化剂和线粒体抑制剂确定这些ROS的来源和重要性。此外，我们将测试这些瞬态ROS是否诱导增强的再灌注否和防止凋亡的保护。在AIM 2中，我们将评估最有效的草药诱导的PC协议赋予保护的途径。我们将使用PKCE易位，AKT磷酸化和AKT活性评估Herb诱导的PC中PKCE和/或AKT的激活。我们还将研究ROS在诱导PKCE和/或AKT激活中的作用，以及该激酶激活对ENOS磷酸化的影响，使用激酶抑制剂，siRNA基因沉默和openos eNOS和AKT-1的敲除策略。这些结果将有助于阐明鼠心肌细胞中重要的PC途径，重点是线粒体氧化剂，某些应激激酶和eNOS如何相互作用以防止I/R损伤。这项工作将用于将Herb-PC的翻译研究计划为我们的心脏骤停的小鼠模型。最后，更好地了解SBE和/或Baicalein PC可能会导致新的氧化剂介导的PC临床疗法。公共卫生相关性：从外行人的角度来看，很少有药物可以防止未来的心脏病发作。此外，许多关于替代药物的草药化合物的研究都集中在其抗氧化作用上。该提案将研究一种实际上增加心脏中氧化应激的草药混合物，可能有助于调节其并防止未来的心脏病发作损伤。