Role of G proteins and modulation of p38 MAPK activation in the protection by nitric oxide against ischemia-reoxygenation injury.
Protein kinase C (PKC)-mediated regulation of the mitogen-activated protein kinases (MAPK) may play a role in the protection afforded by ischemic preconditioning (PC). Nitric oxide (NO) can influence MAPK activation via interaction with PKC or farnesylation of low-molecular-weight (LMWT) G proteins. However, we have recently reported the mechanism of NO-induced cardioprotection to be a PKC-independent process. Therefore, we investigated the role of LMWT G proteins and MAPK signaling in NO-induced cardioprotection against simulated ischemia-reoxygenation (SI-R) injury. Neonatal rat cardiomyocytes treated for 90 min with the NO donor S-nitroso-N-acetyl-l,l-penicillamine (SNAP) 1 mM were protected against 6 h of SI (hypoxic conditions at 37 degrees C with 20 mM lactate, 16 mM KCl at pH 6.2) and 24 h reoxygenation under normal culture conditions. NO-induced protection was blocked by the G protein inhibitor alpha-hydroxyfarnesylphosphonic acid (alphaHFP) 10 microM. We studied the time course of p42/44 and p38 MAPK dual-phosphorylation hourly during SI using phospho-specific antibodies. p38 was phosphorylated during SI and the peak phosphorylation was significantly delayed by SNAP pretreatment. The p38 inhibitor SB203580 1 microM, given during SI, protected against injury. Thus the delay in peak p38 activation may contribute to, rather than be the effect of, NO-induced cardioprotection. We have shown that p38beta does not contribute to the total p38 signal in our extracts. Thus there is no detectable beta isoform. We conclude that the main isoform present in these cells and thought to be responsible for the observed phenomenon, is the alpha isoform.
Rakhit
R D
RD
Department of Cardiology, Kings College London, St. Thomas' Hospital, Lambeth Palace Road, London, SE1 7AH, United Kingdom. roby@rakhit.freeserve.co.uk
Kabir
A N
AN
Mockridge
J W
JW
Saurin
A
A
Marber
M S
MS
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis; D015153:Blotting, Western; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005204:Farnesol / Q000031:analogs & derivatives / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D019157:Ischemic Preconditioning, Myocardial; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D009206:Myocardium / Q000166:cytology; D009569:Nitric Oxide / Q000378:metabolism*; D063065:Organophosphonates / Q000494:pharmacology; D010766:Phosphorylation; D011485:Protein Binding; D020033:Protein Isoforms; D011493:Protein Kinase C / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000517:prevention & control*; D013997:Time Factors; D048051:p38 Mitogen-Activated Protein Kinases
C080570:(alpha-hydroxyfarnesyl)phosphonic acid; D004791:Enzyme Inhibitors; D007093:Imidazoles; D063065:Organophosphonates; D020033:Protein Isoforms; D011725:Pyridines; D009569:Nitric Oxide; D005204:Farnesol; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D019204:GTP-Binding Proteins; C093642:SB 203580