title: Attenuation of acetaldehyde-induced cell injury by overexpression of aldehyde dehydrogenase-2 (ALDH2) transgene in human cardiac myocytes: role of MAP kinase signaling.
abstract: Acetaldehyde, the major metabolite of ethanol, which is far more toxic and reactive than ethanol, may be responsible for alcohol-induced cardiac damage. This study was designed to examine the impact of facilitated acetaldehyde metabolism using transfection of human aldehyde dehydrogenase-2 (ALDH2) transgene on acetaldehyde- and ethanol-induced cell injury. Fetal human cardiac myocytes were transfected with ALDH2, the efficacy of which was verified by flow cytometry, Western blot and ALDH2 activity assays. Generation of reactive oxygen species (ROS) was detected using 5-(6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H2DCFDA). Apoptosis was evaluated by 4',6'-diamidino-2'-phenylindoladihydrochloride (DAPI) fluorescence microscopy, quantitative DNA fragmentation ELISA and caspase 3 activity. Acetaldehyde and ethanol elicited overt ROS generation and apoptosis in human cardiac myocytes following 24-48 h of incubation. Immunostaining revealed activation of the MAP kinase cascades ERK1/2, SAPK/JNK and p38 MAP kinase in acetaldehyde-treated myocytes. Interestingly, ALDH2 transgene significantly attenuated acetaldehyde-induced ROS generation, apoptosis and phosphorylation of ERK1/2 and SAPK/JNK. Time-dependent response (0-12 h) revealed ROS accumulation and activation of MAP kinases prior to acetaldehyde-induced apoptosis. In addition, acetaldehyde-induced ROS generation and apoptosis were antagonized by non-enzymatic antioxidants. Our results suggested that ALDH2 transgene overexpression may effectively alleviate acetaldehyde-elicited cell injury through an ERK1/2 and SPAK/JNK-dependent mechanism. Our data are consistent with the notion of acetaldehyde as a contributor to alcoholic cardiomyopathy and implicate the therapeutic potential of ALDH2 enzyme in alcoholic complications.
authors.affiliation: Center for Cardiovascular Research and Alterative Medicine, Division of Pharmaceutical Sciences, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Shi-Yan
authors.initials: SY
authors.lastname: Li
authors.forename: Qun
authors.initials: Q
authors.lastname: Li
authors.forename: James J
authors.initials: JJ
authors.lastname: Shen
authors.forename: Feng
authors.initials: F
authors.lastname: Dong
authors.forename: Valerie K
authors.initials: VK
authors.lastname: Sigmon
authors.forename: Yizhen
authors.initials: Y
authors.lastname: Liu
authors.forename: Jun
authors.initials: J
authors.lastname: Ren
mesh_terms: D000079:Acetaldehyde / Q000494:pharmacology; D000444:Aldehyde Dehydrogenase / Q000096:biosynthesis / Q000235:genetics*; D000071396:Aldehyde Dehydrogenase, Mitochondrial; D017209:Apoptosis / Q000502:physiology; D015153:Blotting, Western; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000201:enzymology*; D018384:Oxidative Stress / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; C096127:ALDH2 protein, human; D000444:Aldehyde Dehydrogenase; D000071396:Aldehyde Dehydrogenase, Mitochondrial; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D000079:Acetaldehyde