PKC-dependent delayed metabolic preconditioning is independent of transient MAPK activation.
In this study we used an in vitro model of delayed preconditioning to investigate activation of mitogen-activated protein kinases (MAPKs) and their potential role in protection. Neonatal rat cardiomyocytes were preconditioned using a buffer containing glycolytic inhibitors and low pH (minimal metabolic preconditioning; MMPC) consisting of modified Krebs buffer, 10 mM 2-deoxyglucose, and 20 mM lactate, pH 6.8, for 2 h followed by 24 h of simulated reperfusion before lethal simulated ischemia (LSI). MAPK activation during the MMPC protocol was determined using phospho-specific antisera and the effect on protection determined following LSI. Rapid, transient phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38 MAPK was observed during each of the MMPC, reperfusion, and LSI phases; an effect blocked by MAPK inhibitors PD-98059 and SB-203580, respectively, but not by the protein kinase C (PKC) inhibitor Ro31-8220. However, although MMPC was blocked by Ro31-8220, treatment with the MAPK inhibitors during the preconditioning protocol did not block delayed protection conferred by MMPC. Thus the data suggest that, in this model of delayed preconditioning, protection appears to be PKC dependent but independent of ERK1/2 or p38 MAPK activation.
Department of Cardiology, King's College London, The Rayne Institute, St. Thomas' Hospital, London, SE1 7EH, United Kingdom.
J W
JW
Mockridge
A
A
Punn
D S
DS
Latchman
M S
MS
Marber
R J
RJ
Heads
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D003470:Culture Media; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006321:Heart / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000494:pharmacology; D019157:Ischemic Preconditioning, Myocardial; D007700:Kinetics; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D011493:Protein Kinase C / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D048051:p38 Mitogen-Activated Protein Kinases
D003470:Culture Media; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D011725:Pyridines; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one