Role of Mitochondrial Aldehyde Dehydrogenases in Ethanol Metabolism and Toxicity

线粒体醛脱氢酶在乙醇代谢和毒性中的作用

基本信息

批准号：
7847692
负责人：
VASILIS VASILIOU
金额：
$ 19.13万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-06-01 至 2011-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7847692
关键词：
Acetaldehyde Address Alcohol abuse Alcohol consumption Alcohol dehydrogenase Alcoholic Liver Diseases Alcohols Aldehydes Alleles Apoptosis Applications Grants Arts Baculoviruses Blood Brain CYP2E1 gene Cell Line Cells Chronic Cytochrome P450 Drug Metabolic Detoxication Enzymes Ethanol Ethanol Metabolism Ethanol toxicity Exhibits Exons Functional disorder Genetic Polymorphism Goals Human Individual Injury Investigation Knowledge Laboratories Lipid Peroxidation Lipids Liver Metabolism Mitochondria Mitochondrial DNA Molecular Target Mus Organ Pathogenesis Pathway interactions Pattern Persons Physiological Play Point Mutation Principal Investigator Proteins Recombinant Proteins Recombinants Risk Role Testing Time Tissues Toxic effect Transgenic Mice Work aldehyde dehydrogenases base catalase design drinking behavior enzyme activity human tissue innovation insight novel research study

项目摘要

DESCRIPTION (provided by applicant): Chronic alcohol abuse has a variety of pathological consequences including damage to liver, brain and other organs. Some of these pathological effects can be attributed to ethanol metabolism. Ethanol is metabolized to acetaldehyde by the alcohol dehydrogenase enzymes (ADHs), ethanol-inducible cytochrome P450 (CYP2E1) and catalase. Many of the toxic effects of ethanol are due to acetaldehyde and its actions on molecular targets viz. proteins, lipids and mitochondrial DNA. As a result, the role of acetaldehyde metabolism may be crucial for understanding the pathogenesis of tissue injury caused by alcohol consumption. Impaired acetaldehyde metabolism is associated with polymorphisms in the human aldehyde dehydrogenase (ALDH) enzymes; these may influence drinking behavior and risk for developing alcoholic liver disease. Mitochondrial ALDH2 and, to a lesser extent, cytosolic ALDH1A1 enzymes are known to play a major role in acetaldehyde detoxification. Human ALDH2 is polymorphic with 2 distinct alleles, ALDH2*1 and ALDH2*2. ALDH2*2 homozygous individuals are completely devoid of ALDH2 activity, whereas ALDH2*1/2*2 heterozygous individuals exhibit only 30-50% of the normal ALDH activity. This altered enzyme activity has physiological ramifications. For example, after equivalent amounts of alcohol are consumed, blood acetaldehyde levels in ALDH2*2 homozygous individuals are 6-20 times higher than those in ALDH2*1/2*1 individuals in whom acetaldehyde is hardly detectable. ALDH1B1 is a mitochondrial enzyme that is 75% identical to ALDH2 and also may be involved in acetaldehyde metabolism. Although there is a considerable amount of information about ALDH2 and ALDH1A1, very little is known about ALDH1B1. Our working hypothesis for this R21 grant application is two-fold. First, we hypothesize that the mitochondrial ALDH1B1 is a functional enzyme that protects cells by metabolizing acetaldehyde and lipid peroxidation-associated aldehydes. Second, we hypothesize that ALDH2*2 protein may inactivate other ALDHs by interacting with them. For the 2-year period of this application, we propose to characterize the human and mouse ALDH1B1 proteins in relation to: (a) enzymatic function (metabolism of acetaldehyde and lipid peroxidation aldehydes), (b) expression pattern in both mouse and human tissues, and (c) its protective role against aldehyde-induced toxicity and apoptosis. These will be studied using recombinant ALDH1B1 proteins and cell lines expressing, over-expressing or lacking this protein. In addition, we will determine whether ALDH2*2 protein inactivates both ALDH2*1 enzymes and ALDH1B1. This will be accomplished by studying the formation of heterotetramers using recombinant proteins and cell lines expressing these proteins.

描述（由申请人提供）：慢性酒精滥用会带来多种病理后果，包括对肝脏，大脑和其他器官的损害。这些病理作用中的一些可以归因于乙醇代谢。乙醇被酒精脱氢酶（ADHS），乙醇诱导的细胞色素P450（CYP2E1）和过酶代谢。乙醇的许多毒性作用是由于乙醛及其对分子靶标的作用，即。蛋白质，脂质和线粒体DNA。结果，乙醛代谢的作用对于理解饮酒引起的组织损伤的发病机理至关重要。乙醛代谢受损与人醛脱氢酶（ALDH）酶的多态性有关。这些可能会影响饮酒行为和患病肝病的风险。线粒体ALDH2，并且在较小程度上，已知胞质Aldh1a1酶在乙醛排毒中起主要作用。人AldH2是多态性的，具有2个不同的等位基因，Aldh2*1和Aldh2*2。 ALDH2*2纯合子完全没有ALDH2活性，而ALDH2*1/2*2杂合子仅显示出正常ALDH活性的30-50％。这种改变的酶活性具有生理后果。例如，在消耗同等量的酒精之后，Aldh2*2纯合子的血乙醛水平比Aldh2*1/2*1个个体高6-20倍，几乎无法检测到乙醛。 ALDH1B1是一种线粒体酶，与ALDH2相同，也可能参与乙醛代谢。尽管关于AldH2和AldH1A1的信息有大量信息，但对AldH1B1的了解鲜为人知。我们对此R21赠款应用程序的工作假设是两倍。首先，我们假设线粒体ALDH1B1是一种功能性酶，可通过代谢乙醛和脂质过氧化相关的醛来保护细胞。其次，我们假设ALDH2*2蛋白可能通过与它们相互作用而使其他ALDH灭活。在此应用的两年期间，我们建议以：（a）酶促功能（乙醛和脂质过氧化醛的代谢），（a）在小鼠和人体组织中的表达模式（c）保护性抗毒性的作用和对aptede的作用。这些将使用重组ALDH1B1蛋白和表达，过表达或缺乏该蛋白的细胞系进行研究。此外，我们将确定ALDH2*2蛋白是否使ALDH2*1酶和ALDH1B1都失活。这将通过使用表达这些蛋白质的重组蛋白和细胞系研究杂晶剂的形成来实现。