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.

描述（由申请人提供）：该提案建立在表明草药提取物黄芩（SbE）及其主要成分黄芩素可以模拟心脏预处理（PC）的许多重要成分的研究基础上，即触发瞬时线粒体氧化信号传导，激活生存激酶Akt，减弱再灌注活性氧 (ROS) 并增加再灌注一氧化氮 (NO) 的产生。它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 (I/R) 模型中提供显着保护：鸡心肌细胞、小鼠心肌细胞和小鼠心脏骤停。一种草药提取物已在流行的替代医学中使用，作为药物心脏 PC 剂用于有不良心脏事件风险的患者具有实际优势。该提案旨在通过确定产生保护表型的机制来进一步检查 SbE 和/或黄芩素在小鼠心肌细胞中诱导的 PC 保护。我们假设 SbE 和/或黄芩素将通过短暂的 ROS 生成诱导 PC 对小鼠心肌细胞 I/R 损伤的保护，从而启动 PKCe 和/或 Akt 的激活，从而导致 eNOS 激活并增加再灌注 NO 的生成。具体来说，目标 1 将优化触发 ROS 介导的 PC 的 SbE 和/或黄芩素的剂量，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，我们将测试这些短暂的 ROS 是否会诱导 NO 再灌注增强和细胞凋亡保护。在目标 2 中，我们将评估最有效的草药诱导 PC 方案提供保护的途径。我们将使用 PKCe 易位、Akt 磷酸化和 Akt 活性评估草药诱导的 PC 中 PKCe 和/或 Akt 的激活。我们还将使用激酶抑制剂、siRNA 基因沉默和 eNOS 和 Akt-1 敲除策略来检查 ROS 在诱导 PKCe 和/或 Akt 激活中的作用，以及该激酶激活对 eNOS 磷酸化和 NO 生成的影响。这些结果将有助于阐明小鼠心肌细胞中重要的 PC 通路，重点关注线粒体氧化剂、某些应激激酶和 eNOS 如何相互作用以防止 I/R 损伤。这项工作将用于计划将 Herb-PC 转化为我们的心脏骤停小鼠模型。最后，更好地了解 SbE-和/或黄芩素 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，很少有药物可以预防未来的心脏病发作。此外，许多关于草药化合物作为替代药物的研究都集中在它们的抗氧化作用上。该提案将研究一种草药混合物，这种混合物实际上会增加心脏中的一种氧化应激，这可能有助于调节心脏并防止未来心脏病发作造成的损伤。