PKC-dependent activation of p44/p42 MAPKs during myocardial ischemia-reperfusion in conscious rabbits. Am J Physiol 1999 May;276(5):H1468-81
Date
05/18/1999Pubmed ID
10330229DOI
10.1152/ajpheart.1999.276.5.H1468Scopus ID
2-s2.0-0032993140 (requires institutional sign-in at Scopus site) 209 CitationsAbstract
Using conscious rabbits, we examined the effect of ischemic preconditioning (PC) on p44 and p42 mitogen-activated protein kinases (MAPKs). We found that both isoforms contribute significantly to total MAPK activity in the heart (in-gel kinase assay: p44, 59 +/- 1%; p42, 41 +/- 1%). Ischemic PC (6 cycles of 4-min occlusion/4-min reperfusion) elicited a pronounced increase in total cellular MAPK activity (+89%). This increase, which occurred exclusively in the nuclear fraction, was contributed by both isoforms (in-gel kinase assay: p44, +97%; p42, +210%) and was accompanied by migration of the two proteins from the cytosolic to the nuclear compartment. In control rabbits, MAPK kinase (MEK)1 and MEK2, direct activators of p44 and p42 MAPKs, were located almost exclusively in the cytosolic fraction. Ischemic PC induced a marked increase in cytosolic MEK activity (+164%), whereas nuclear MEK activity did not change, indicating that MEK-induced activation of MAPKs occurred in the cytosolic compartment. Activation of MAPKs after ischemic PC was completely blocked by the protein kinase C (PKC) inhibitor chelerythrine. Selective overexpression of PKC-epsilon in adult rabbit cardiomyocytes induced activation of both p44 and p42 MAPKs and reduced lactate dehydrogenase release during simulated ischemia-reperfusion, which was abolished by the MEK inhibitor PD-98059. The results demonstrate that 1) ischemic PC induces a rapid activation of p44 and p42 MAPKs in hearts of conscious rabbits; 2) the mechanism of this phenomenon involves activation of p44 and p42 MAPKs in the cytosol and their subsequent translocation to the nucleus; and 3) it occurs via a PKC-mediated signaling pathway. The in vitro data implicate PKC-epsilon as the specific isoform responsible for PKC-induced MAPK activation and suggest that p44/p42 MAPKs contribute to PKC-epsilon-mediated protection against simulated ischemia. The results are compatible with the hypothesis that p44 and p42 MAPKs may play a role in myocardial adaptations to ischemic stress.
Author List
Ping P, Zhang J, Cao X, Li RC, Kong D, Tang XL, Qiu Y, Manchikalapudi S, Auchampach JA, Black RG, Bolli RAuthor
John A. Auchampach PhD Professor in the Pharmacology and Toxicology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AlkaloidsAmino Acid Sequence
Animals
Benzophenanthridines
Calcium-Calmodulin-Dependent Protein Kinases
Cell Compartmentation
Cell Nucleus
Cells, Cultured
Consciousness
Coronary Vessels
Cytosol
DNA, Complementary
Enzyme Activation
Ischemic Preconditioning
Isoenzymes
MAP Kinase Kinase 1
MAP Kinase Kinase 2
Male
Mitogen-Activated Protein Kinase 1
Mitogen-Activated Protein Kinase 3
Mitogen-Activated Protein Kinase Kinases
Mitogen-Activated Protein Kinases
Molecular Sequence Data
Muscle Fibers, Skeletal
Myocardial Ischemia
Myocardial Reperfusion Injury
Phenanthridines
Protein Kinase C
Protein Kinase C-epsilon
Protein-Tyrosine Kinases
Rabbits
Signal Transduction