AGING, LIPID PEROXIDATION, AND CARDIAC REPERFUSION

衰老、脂质过氧化和心脏再灌注

• 批准号: 6137073
• 负责人: LUKE I. SZWEDA
• 金额: $ 21.33万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2003-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6137073
• 关键词: age difference; cell senescence; cellular pathology; cellular respiration; endopeptidases; enzyme activity; enzyme inhibitors; free radicals; histology; immunochemistry; laboratory rat; lipid peroxides; lipids; mass spectrometry; mitochondria; myocardial ischemia /hypoxia; oxidative stress; peroxidation; posttranslational modifications; protein localization; protein purification; protein structure function; reperfusion; respiratory enzyme; superoxides

DESCRIPTION (Adapted from the Applicant's Abstract): Reperfusion of cardiac tissue results in declines in mitochondrial respiration, the severity of which increases with age. Critical to the energy status and function of the heart, cardiac mitochondria exhibit reperfusion-induced increases in free radical production. A direct link between free radicals and mitochondrial dysfunction has yet to be established. 4- Hydroxy-2-nonenal (HNE), a major product of lipid peroxidation readily reacts with and inactivates enzymes. Work from the Principal Investigator's laboratory had established that reperfusion results in modification of specific proteins by HNE. The level of HNE modification increases with age and parallels declines in mitochondrial respiration. Treatment of intact cardiac mitochondria with concentrations of HNE expected during reperfusion causes rapid declines in NADH-dependent respiration similar to that observed during reperfusion. The Principal Investigator thus proposes that: Reperfusion-induced declines in mitochondrial respiration are due, in part, to modification of specific mitochondrial proteins(s) by HNE and that these processes contribute to age-related increases in myocardial reperfusion injury. To test this hypothesis, hearts isolated from rats of different ages will be subjected to varying durations of ischemia and reperfusion. Mitochondria will then be isolated to determine: 1. Specific respiratory enzymes inactivated during ischemia and reperfusion. 2. The identities of mitochondrial protein(s) modified by HNE and the level of HNE modification. 3. Changes in mitochondrial susceptibility to HNE damage and superoxide anion generation. Chemical, immunochemical, and mass spectroscopic techniques will be utilized to detect and purify HNE-modified protein. Relationships between the level and identity of mitochondrial proteins modified by HNE (Aim 2) and those exhibiting reperfusion-induced declines in activity (Aim 1) will define mechanisms responsible for loss in mitochondrial function during reperfusion. Determinants of HNE-mediated damage to mitochondria will be established by evaluating changes in mitochondrial properties which occur during aging and ischemia (Aim 1) and result in elevated rates of HNE formation and/or increased susceptibility of specific respiratory enzymes to modification (Aim 3). Identification of specific mechanisms of myocardial reperfusion injury and conditions under which they occur is necessary if intervention is to be achieved.

描述（改编自申请人的摘要）：再灌注 心脏组织导致线粒体呼吸下降 其严重程度随着年龄的增长而增加。对能源状况至关重要 心脏功能，心脏线粒体表现出再灌注诱导 自由基产生增加。免费之间的直接链接 自由基和线粒体功能障碍之间的关系尚未确定。 4- 羟基-2-壬烯醛 (HNE)，脂质过氧化反应的主要产物 与酶发生反应并使酶失活。校长的工作 研究人员的实验室已确定再灌注会导致 通过 HNE 修饰特定蛋白质。 HNE修改级别 随着年龄的增长而增加，并且与线粒体呼吸的减少相似。 用浓度的 HNE 处理完整的心脏线粒体 再灌注期间预期会导致 NADH 依赖性迅速下降 呼吸与再灌注期间观察到的相似。校长 因此，研究者提出：再灌注引起的 线粒体呼吸部分是由于特定的修饰 HNE 产生的线粒体蛋白以及这些过程有助于 年龄相关的心肌再灌注损伤增加。 为了验证这一假设，从不同年龄的大鼠中分离出心脏 会经历不同持续时间的缺血和再灌注。 然后分离线粒体以确定： 1. 缺血时特定呼吸酶失活 再灌注。 2. HNE 修饰的线粒体蛋白的身份及 HNE 修改水平。 3. 线粒体对HNE损伤和超氧化物敏感性的变化 阴离子的产生。 化学、免疫化学和质谱技术将 用于检测和纯化 HNE 修饰的蛋白质。人际关系 HNE 修饰的线粒体蛋白的水平和特性之间的关系 （目标 2）以及表现出再灌注引起的活动下降的患者 （目标 1）将定义导致线粒体损失的机制 再灌注期间的功能。 HNE 介导的损伤的决定因素 将通过评估线粒体的变化来建立线粒体 老化和缺血期间发生的特性（目标 1）并导致 HNE 形成率升高和/或 HNE 易感性增加 特定的呼吸酶进行修饰（目标 3）。鉴定 心肌再灌注损伤的具体机制和条件 如果要实现干预，它们的发生是必要的。