title: H(2)O(2) regulates cardiac myocyte phenotype via concentration-dependent activation of distinct kinase pathways.
abstract: Reactive oxygen species (ROS) can act as signaling molecules to stimulate either hypertrophy or apoptosis in cardiac myocytes. We tested the hypothesis that the phenotypic effects of ROS are due to differential, concentration-dependent activation of specific kinase signaling pathways. Adult rat ventricular myocytes were exposed to H(2)O(2) over a broad concentration range (10-1000 microM). Low concentrations of H(2)O(2) (10-30 microM) increased protein synthesis without affecting survival. Higher concentrations of H(2)O(2) (100-200 microM) increased apoptosis (assessed by TUNEL). Still higher concentrations of H(2)O(2) (300-1000 microM) caused both apoptosis and necrosis. A hypertrophic concentration of H(2)O(2) (10 microM) increased the activity of ERK1/2, but not that of JNK, p38 kinase or Akt. An apoptotic concentration of H(2)O(2) (100 microM) activated JNK, p38 kinase and Akt, and further activated ERK1/2. The MEK1/2 inhibitor U0126 prevented the hypertrophic effect of 10 microM H(2)O(2). The apoptotic effect of 100 microM H(2)O(2) was inhibited bya dominant-negative JNK adenovirus, and was potentiated by U0126 or an Akt inhibitor. Thus, the concentration-dependent effects of ROS on myocyte hypertrophy and growth are due, at least in part, to the differential activation of specific kinase signaling pathways that regulate hypertrophy and apoptosis.
authors.affiliation: Myocardial Biology Unit and Cardiovascular Division, Boston University Medical Center, and School of Medicine, 88 East Newton Street, MA 02118, Boston, USA.
authors.forename: Susan H
authors.initials: SH
authors.lastname: Kwon
authors.forename: David R
authors.initials: DR
authors.lastname: Pimentel
authors.forename: Andrea
authors.initials: A
authors.lastname: Remondino
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Sawyer
authors.forename: Wilson S
authors.initials: WS
authors.lastname: Colucci
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology*; D020287:In Situ Nick-End Labeling; D007930:Leucine / Q000737:chemistry; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D032342:Muscle Cells / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D009336:Necrosis; D010641:Phenotype; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species; D015398:Signal Transduction; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D007930:Leucine