Consecutive pharmacological activation of PKA and PKC mimics the potent cardioprotection of temperature preconditioning.
OBJECTIVE
Temperature preconditioning (TP) provides very powerful protection against ischaemia/reperfusion. Understanding the signalling pathways involved may enable the development of effective pharmacological cardioprotection. We investigated the interrelationship between activation of protein kinase A (PKA) and protein kinase C (PKC) in the signalling mechanisms of TP and developed a potent pharmacological intervention based on this mechanism.


RESULTS
Isolated rat hearts were subjected to TP, 30 min global ischaemia, and 60 min reperfusion. Other control and TP hearts were perfused with either sotalol (β-adrenergic blocker) or H-89 (PKA inhibitor). Some hearts were pre-treated with either isoproterenol (β-adrenergic agonist) or adenosine (PKC activator) that were given alone, simultaneously, or sequentially. Pre-treatment with isoproterenol, adenosine, and the consecutive isoproterenol/adenosine treatment was also combined with the PKC inhibitor chelerythrine. Cardioprotection was evaluated by haemodynamic function recovery, lactate dehydrogenase release, measurement of mitochondrial permeability transition pore opening, and protein carbonylation during reperfusion. Cyclic AMP and PKA activity were increased in TP hearts. H-89 and sotalol blocked the cardioprotective effect of TP and TP-induced PKC activation. Isoproterenol, adenosine, and the consecutive treatment increased PKC activity during pre-ischaemia. Isoproterenol significantly reduced myocardial glycogen content. Isoproterenol and adenosine, alone or simultaneously, protected hearts but the consecutive treatment gave the highest protection. Cardioprotective effects of adenosine were completely blocked by chelerythrine but those of the consecutive treatment only attenuated.


CONCLUSIONS
The signal transduction pathway of TP involves PKA activation that precedes PKC activation. Pharmacologically induced consecutive PKA/PKC activation mimics TP and induces extremely potent cardioprotection.
Khaliulin
Igor
I
Department of Biochemistry and the Bristol Heart Institute, University of Bristol, University Walk, Bristol BS8 1TD, UK. i.khaliulin@bristol.ac.uk
Parker
Joanna E
JE
Halestrap
Andrew P
AP
D000241:Adenosine / Q000494:pharmacology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000494:pharmacology*; D006003:Glycogen / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D006439:Hemodynamics / Q000187:drug effects; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000187:drug effects / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology; D010477:Perfusion; D010766:Phosphorylation; D050050:Protein Carbonylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function; D015398:Signal Transduction / Q000187:drug effects; D013696:Temperature; D013997:Time Factors; D016277:Ventricular Function, Left / Q000187:drug effects
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D002316:Cardiotonic Agents; D020536:Enzyme Activators; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D047428:Protein Kinase Inhibitors; D006003:Glycogen; D007770:L-Lactate Dehydrogenase; D051057:Proto-Oncogene Proteins c-akt; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D038362:Glycogen Synthase Kinase 3; D000241:Adenosine; D007545:Isoproterenol