4-hydroxy-2-nonenal in mitochondrial DNA damage and contractile dysfunction in diabetic heart: a role for aldehyde dehydrogenase 2

4-羟基-2-壬烯醛在糖尿病心脏线粒体 DNA 损伤和收缩功能障碍中的作用：乙醛脱氢酶 2 的作用

• 批准号: 9756477
• 负责人: Suresh Selvaraj Palaniyandi
• 金额: $ 38.24万
• 依托单位: HENRY FORD HEALTH SYSTEM
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9756477
• 关键词: 4 hydroxynonenal; Aldehydes; Amino Acids; Asians; Attenuated; Base Excision Repairs; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cardiovascular system; DNA; DNA Damage; DNA Repair; DNA Repair Enzymes; Data; Dependovirus; Development; Diabetes Mellitus; Diabetic mouse; Drug Metabolic Detoxication; Enzymes; Exhibits; Functional disorder; Genes; Glucose; Goals; Guanine; Heart; Heart Diseases; Heart Mitochondria; High Fat Diet; Hyperglycemia; Impairment; In Situ; Intervention; Knock-in; Lead; Mass Spectrum Analysis; Mediating; Mitochondria; Mitochondrial DNA; Modeling; Mus; Mutant Strains Mice; Mutation; Myocardial; Myocardial dysfunction; Myocardium; Non-Insulin-Dependent Diabetes Mellitus; Oxidative Stress; Oxides; Pathogenesis; Pathology; Pharmaceutical Preparations; Physiological; Proteins; Reactive Oxygen Species; Reporting; Respiration; Role; Site-Directed Mutagenesis; Small Interfering RNA; Streptozocin; Stress; Structure; Testing; Transfection; Type 2 diabetic; Variant; adduct; aldehyde dehydrogenases; base; covalent bond; diabetic; diabetic cardiomyopathy; diabetic patient; heart damage; heart function; improved; indexing; macromolecule; molecular modeling; mutant; novel; overexpression; promoter; repair enzyme; repaired; respiratory; therapeutic target

Project Abstract: Diabetes mellitus (DM) afflicts 26 million people in the US. Around 65% of these diabetic patients die of cardiovascular complications. We and others have found that DM increases reactive oxygen species (ROS)- mediated aldehydes like 4-hydroxy-2-nonenal (4HNE) levels. 4HNE forms covalent bonds with macromolecules known as adducts, which lead to cellular damage and decreased cardiac function. Aldehyde dehydrogenase (ALDH2) is a cardiac mitochondrial enzyme that detoxifies 4HNE greatly in the heart. We and others have reported that in streptozotocin-induced hyperglycemic models increase in 4HNE protein adducts and decrease in myocardial ALDH2 activity correlate with cardiomyopathy. Although we think this causes cardiac dysfunction, the exact mechanism is unclear. However, most diabetic patients have type-2 DM. Thus, it is imperative to investigate whether increased mitochondrial 4HNE and lower ALDH2 activity in the cardiomyocytes contribute to cardiac dysfunction in type-2 DM models. We recently demonstrated that high glucose stress or 4HNE administration decreased mitochondrial respiration with increased mitochondrial DNA (mtDNA) damage in cultured cardiomyocytes. In our preliminary study using type-2 diabetic mouse heart, we found an increase in mitochondrial levels of 8-hydroxyguanine (8OHG), an oxidized mtDNA product, which is primarily repaired by 8- oxoguanine glycosylase (OGG)-1. Next, we found increased 4HNE adduct formation on OGG-1 and reduced cardiac OGG-1 levels. These data suggest that 4HNE adduction on OGG-1 reduces its level and activity thereby raising the unmetabolized 8OHG level. Thus, we postulate that 4HNE-mediated mtDNA damage is part of the mechanism by which lower ALDH2 causes mitochondrial respiratory dysfunction and thus cardiac contractile dysfunction. To test our idea, we will use a high-fat diet induced type-2 DM model in wild type C57BL/6 and ALDH2*2 mutant mice. This mutation mimics East Asians with the E487K variant (ALDH2*2), which exhibits lower ALDH2 activity. We will overexpress ALDH2 and OGG-1 genes in the myocardium in situ or treat our diabetic mice with Alda-1, the only specific drug available to improve the catalytic activity of both wild type and mutant ALDH2. We propose following two specific aims: Aim 1. To determine whether increased 4HNE adduction on mtOGG-1 causes mtDNA damage, poor mitochondrial respiration, and impaired cardiomyocyte contractility in type-2 DM. Aim 2. To determine whether decreasing 4HNE-mediated mtDNA damage after the onset of cardiac dysfunction in type2-DM attenuates pathogenesis of cardiomyopathy. This study will identify a novel role of ALDH2 in type-2 DM mediated cardiac dysfunction and establish that ALDH2 could be a therapeutic target for restoring cardiac function in type-2 diabetic patients.

项目摘要： 糖尿病 (DM) 困扰着美国 2600 万人。大约65%的糖尿病患者死于 心血管并发症。我们和其他人发现 DM 会增加活性氧 (ROS) - 介导的醛类，如 4-羟基-2-壬烯醛 (4HNE) 水平。 4HNE与大分子形成共价键 称为加合物，会导致细胞损伤和心脏功能下降。乙醛脱氢酶 (ALDH2) 是一种心脏线粒体酶，可在心脏中大量解毒 4HNE。我们和其他人有 报道称，在链脲佐菌素诱导的高血糖模型中，4HNE 蛋白加合物增加并减少 心肌 ALDH2 活性与心肌病相关。虽然我们认为这会导致心脏功能障碍， 确切的机制尚不清楚。然而，大多数糖尿病患者患有2型糖尿病。因此，当务之急是 研究心肌细胞中线粒体 4HNE 增加和 ALDH2 活性降低是否有助于 2 型糖尿病模型中的心功能障碍。我们最近证明，高葡萄糖应激或 4HNE 给药减少了线粒体呼吸，增加了线粒体 DNA (mtDNA) 损伤 培养的心肌细胞。在我们使用 2 型糖尿病小鼠心脏进行的初步研究中，我们发现 线粒体中 8-羟基鸟嘌呤 (8OHG) 的水平，这是一种氧化的 mtDNA 产物，主要由 8- 氧代鸟嘌呤糖基化酶（OGG）-1。接下来，我们发现 OGG-1 上的 4HNE 加合物形成增加，并减少 心脏 OGG-1 水平。这些数据表明 OGG-1 上的 4HNE 加合降低了其水平和活性，从而降低了 OGG-1 的水平和活性。 提高未代谢的 8OHG 水平。因此，我们假设 4HNE 介导的 mtDNA 损伤是 降低 ALDH2 导致线粒体呼吸功能障碍并进而导致心肌收缩的机制 功能障碍。为了测试我们的想法，我们将在野生型 C57BL/6 和 ALDH2*2 突变小鼠。这种突变模仿东亚人的 E487K 变体 (ALDH2*2)，表现出 降低 ALDH2 活性。我们将在心肌中原位过度表达 ALDH2 和 OGG-1 基因或治疗我们的 Alda-1 是唯一可提高野生型和糖尿病小鼠催化活性的特异性药物 突变型 ALDH2。我们提出以下两个具体目标： 目标 1. 确定 mtOGG-1 上 4HNE 内收增加是否会导致 mtDNA 损伤，较差 2 型糖尿病中线粒体呼吸和心肌细胞收缩力受损。 目标 2. 确定心脏病发作后是否可以减少 4HNE 介导的 mtDNA 损伤 2 型糖尿病的功能障碍会减弱心肌病的发病机制。 这项研究将确定 ALDH2 在 2 型糖尿病介导的心脏功能障碍中的新作用，并确定 ALDH2 可能成为恢复 2 型糖尿病患者心脏功能的治疗靶点。