title: Advanced glycation endproduct induces ROS accumulation, apoptosis, MAP kinase activation and nuclear O-GlcNAcylation in human cardiac myocytes.
abstract: Accumulation of advanced glycation endproduct (AGE) has been implicated in the pathogenesis of diabetic complications. However, the precise role and mechanism behind AGE-associated diabetic heart injury are not fully clear. This study was designed to evaluate the effect of AGE on accumulation of reactive oxygen species (ROS), apoptosis, mitogen-activated protein kinase (MAPK) activation and nuclear O-GlcNAcylation in fetal human cardiac myocytes. Myocytes were maintained for 24-72 h in a defined culture medium containing high glucose, the AGE carbon precursor methylglyoxal (MG), and MG-AGE derived from MG and bovine serum albumin (BSA). Generation of ROS was detected by 5-(6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate. Apoptosis was evaluated by caspase-3 activity and quantitative DNA fragmentation. Both high glucose (25.5 mM) and MG (200 microM) significantly enhanced ROS and AGE formation with greater effects elicited by MG. Both high glucose and MG-AGE significantly facilitated apoptosis with a more predominant effect from MG-AGE. In addition, phosphorylation of MAPK cascade [extracellular signal-regulated kinase-1/2 (ERK1/2) and p38] and nuclear O-GlcNAcylation were enhanced in MG-AGE-treated myocytes, similar to those elicited by high glucose. MG-AGE-induced phosphorylation of ERK1/2 and p38 was nullified by neutralizing AGE with specific anti-AGE antibody but not nonspecific antiserum. Collectively, these results indicated that AGE or its precursor MG may trigger ROS generation, apoptosis, MAPK activation and nuclear O-GlcNAcylation in human cardiac myocytes, in a manner reminiscent of high extracellular glucose.
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: Valerie K
authors.initials: VK
authors.lastname: Sigmon
authors.forename: Sara A
authors.initials: SA
authors.lastname: Babcock
authors.forename: Jun
authors.initials: J
authors.lastname: Ren
mesh_terms: D000215:Acylation; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002417:Cattle; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D053938:DNA Fragmentation; D005333:Fetus / Q000166:cytology; D005947:Glucose / Q000494:pharmacology; D017127:Glycation End Products, Advanced / Q000494:pharmacology*; D006031:Glycosylation; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000096:biosynthesis*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism*; D011765:Pyruvaldehyde / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000494:pharmacology
chemical_list: D017127:Glycation End Products, Advanced; D017382:Reactive Oxygen Species; D012710:Serum Albumin, Bovine; D011765:Pyruvaldehyde; D017351:N-Acetylglucosaminyltransferases; C449880:O-GlcNAc transferase; D020929:Mitogen-Activated Protein Kinase Kinases; D053148:Caspase 3; D005947:Glucose