TY - JOUR
T1 - Role of G proteins and modulation of p38 MAPK activation in the protection by nitric oxide against ischemia-reoxygenation injury
AU - Rakhit, Roby D.
AU - Kabir, Alamgir N.M.
AU - Mockridge, James W.
AU - Saurin, Adrian
AU - Marber, Michael S.
PY - 2001/9/7
Y1 - 2001/9/7
N2 - 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°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 α-hydroxyfarnesylphosphonic acid (αHFP) 10 μM. We studied the time course of p42/44 and p38 MAPK dual-phosphorylation hourly during SI using phosphospecific antibodies, p38 was phosphorylated during SI and the peak phosphorylation was significantly delayed by SNAP pretreatment. The p38 inhibitor SB203580 1 μM, 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 p38β does not contribute to the total p38 signal in our extracts. Thus there is no detectable β isoform. We conclude that the main isoform present in these cells and thought to be responsible for the observed phenomenon, is the α isoform,
AB - 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°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 α-hydroxyfarnesylphosphonic acid (αHFP) 10 μM. We studied the time course of p42/44 and p38 MAPK dual-phosphorylation hourly during SI using phosphospecific antibodies, p38 was phosphorylated during SI and the peak phosphorylation was significantly delayed by SNAP pretreatment. The p38 inhibitor SB203580 1 μM, 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 p38β does not contribute to the total p38 signal in our extracts. Thus there is no detectable β isoform. We conclude that the main isoform present in these cells and thought to be responsible for the observed phenomenon, is the α isoform,
KW - G proteins
KW - Mitogen-activated protein kinase
KW - Nitric oxide
KW - P38
KW - Preconditioning
UR - http://www.scopus.com/inward/record.url?scp=0034810420&partnerID=8YFLogxK
U2 - 10.1006/bbrc.2001.5477
DO - 10.1006/bbrc.2001.5477
M3 - Article
C2 - 11527399
AN - SCOPUS:0034810420
VL - 286
SP - 995
EP - 1002
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 5
ER -