Ecto-5'-nucleotidase plays a role in the cardioprotective effects of heat shock protein 72 in ischemia-reperfusion injury in rat hearts.
OBJECTIVE
Heat shock protein 72 (HSP72) is involved in the myocardial self-preservation system under several conditions such as ischemia-reperfusion injury or late preconditioning. However, its mechanism is not fully understood. Ecto-5'-nucleotidase is a key enzyme for synthesizing adenosine and plays an important role in ischemic preconditioning. In this study, we tested the hypothesis that ecto-5'-nucleotidase plays a role in the cardioprotection of HSP72.


METHODS
Rat hearts (H group, n=6) were transfected with HSP72 gene by an intracoronary infusion of hemagglutinating virus of Japan (HVJ)-liposome complex. Control hearts (C group, n=6) were transfected with the beta-galactosidase gene. Following 30 min of normothermic ischemia, grafts were reperfused using Langendorff apparatus.


RESULTS
The activity of ecto-5'-nucleotidase was significantly higher in H group than C group both before and after ischemia-reperfusion (H vs. C; 0.51+/-0.05 vs. 0.29+/-0.06, and 1.41+/-0.15 vs. 0.85+/-0.11 nmol/mg protein/min, P<0.05). H group also showed significant better functional recoveries than C group (P<0.05), as well as less creatine phosphokinase leakage (4.4+/-2.8 vs. 14.2+/-3.4 mU/min, P<0.05) and higher adenosine release (247.5+/-35.1 vs. 54.3+/-1.7 pmol/min, P<0.05). Administration of alpha,beta-methylene adenosine diphosphate (AMP-CP), an inhibitor of ecto-5'-nucleotidase, significantly diminished the tolerance to ischemia-reperfusion injury in H group (P<0.05).


CONCLUSIONS
These results demonstrated that ecto-5'-nucleotidase activated by an overexpression of HSP72 attenuated ischemia-reperfusion injury in the rat myocardium. They suggest that ecto-5'-nucleotidase plays a role in the cardioprotective effects of HSP72 in rat hearts.
Sakaguchi
T
T
Department of Surgery, Course of Interventional Medicine (E1), Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, 565-0871, Osaka, Japan.
Sawa
Y
Y
Kitakaze
M
M
Suzuki
K
K
Nishimura
M
M
Kaneda
Y
Y
Matsuda
H
H
D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D050884:HSP72 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection
D004791:Enzyme Inhibitors; D050884:HSP72 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C523965:alpha,beta-methyleneadenosine 5'-diphosphate; D000244:Adenosine Diphosphate; D000251:Adenosine Triphosphatases; C027201:ectoATPase