Activation of Akt during simulated ischemia/reperfusion in cardiac myocytes.
In the present study we have investigated whether Akt was activated during simulated ischemia (SI) and simulated ischemia/reperfusion (SI/R) in neonatal rat cardiomyocytes. Akt was phosphorylated on both S473 and T308 residues after 10 min of simulated SI/R and remained elevated for 60 min before returning to basal levels after 2 h. No phosphorylation was observed during SI alone. SI/R-stimulated Akt activation was inhibited by the phosphatidylinositol 3-kinase (PI3-K) inhibitor wortmannin, the tyrosine kinase inhibitor genistein and the Src tyrosine kinase inhibitor PP2, indicating a requirement for tyrosine kinase activity in Akt activation. Furthermore, SB203580, a p38 MAPK inhibitor, partially inhibited Akt activation. SI/R also induced the phosphorylation of PHAS-I, a downstream Akt target, in a wortmannin-dependent manner. These results demonstrate for the first time that SI/R stimulates Akt activation via PI3-K-and Src tyrosine kinase-dependent pathways, whereas p38 MAPK appears to be involved in maintaining Akt activation.
Mockridge
J W
JW
Department of Cardiology, Rayne Institute, King's College London, St Thomas' Hospital, Lambeth Palace Road, London, SE1 7EH, United Kingdom.
Marber
M S
MS
Heads
R J
RJ
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007700:Kinetics; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000378:metabolism*; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D051058:Oncogene Protein v-akt; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D010768:Phosphoserine; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D015682:Retroviridae Proteins, Oncogenic / Q000378:metabolism*; D000077191:Wortmannin
D000730:Androstadienes; D004791:Enzyme Inhibitors; D007093:Imidazoles; D011725:Pyridines; D015682:Retroviridae Proteins, Oncogenic; D010768:Phosphoserine; D019000:Phosphotyrosine; D019833:Genistein; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; D051058:Oncogene Protein v-akt; C093642:SB 203580; D000077191:Wortmannin