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)在美国困扰着2600万人。这些糖尿病患者中约65%死于 心血管并发症。我们和其他人发现，糖尿病会增加活性氧自由基(ROS)- 介导的醛，如4-羟基-2-壬烯醛(4HNE)水平。4HNE与大分子形成共价键 被称为加合物，会导致细胞损伤和心脏功能下降。乙醛脱氢酶 (ALDH2)是一种心肌线粒体酶，能极大地解毒心脏中的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蛋白加合物增加而减少 在心肌中，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，大多数糖尿病患者都患有2型糖尿病。因此，迫切需要 研究心肌细胞中线粒体4HNE增加和ALDH2活性降低是否起作用 与2型糖尿病模型的心功能不全有关。我们最近证明，高糖应激或4HNE 给药降低线粒体呼吸，增加线粒体DNA损伤 培养的心肌细胞。在我们对2型糖尿病小鼠心脏的初步研究中，我们发现 线粒体8-羟基鸟嘌呤(8OHG)是一种氧化的mtDNA产物，主要由8-羟基鸟嘌呤修复。 氧鸟嘌呤糖基酶(OGG)-1。接下来，我们发现Ogg-1上4HNE加合物的形成增加，而减少 心脏Ogg-1水平。这些数据表明，Ogg-1上的4HNE加合物降低了Ogg-1的水平和活性 提高未代谢的80HG水平。因此，我们假设4HNE介导的线粒体DNA损伤是 低ALDH2导致线粒体呼吸功能障碍从而导致心肌收缩的机制 功能障碍。为了验证我们的想法，我们将使用高脂饮食诱导的野生型C57BL/6和2型DM模型 ALDH2*2突变小鼠。这种突变模仿东亚人的E487K变异(ALDH2*2)，表现为 降低ALDH2活性。我们将在原位心肌中过表达ALDH2和OGG-1基因或治疗我们的 糖尿病小鼠服用Alda-1，这是唯一可用于提高野生型和 突变体ALDH2。我们提出以下两个具体目标： 目的1.确定mtOGG-1上4HNE内收增加是否导致mtDNA损伤， 2型糖尿病患者线粒体呼吸和心肌细胞收缩功能受损。 目的2.确定心脏骤停后是否能减少4HNE介导的线粒体DNA损伤 2型糖尿病的功能障碍可减轻心肌病的发病机制。 这项研究将确定ALDH2在2型糖尿病介导的心功能障碍中的新作用，并建立 ALDH2可作为恢复2型糖尿病患者心功能的治疗靶点。