Ischemic preconditioning affects hexokinase activity and HKII in different subcellular compartments throughout cardiac ischemia-reperfusion

• Published in: Journal of applied physiology (1985) 2009-06, Vol.106 (6), p.1909-1916
• Main Authors: Gurel, Ebru, Smeele, Kirsten M, Eerbeek, Otto, Koeman, Anneke, Demirci, Cihan, Hollmann, Markus W, Zuurbier, Coert J
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cardiovascular disease; Cell Fractionation; Cells; Cellular Structures - enzymology; Cytosol - enzymology; Enzymes; Fundamental and applied biological sciences. Psychology; Hexokinase - metabolism; Ischemia; Ischemic Preconditioning, Myocardial; Kinases; Male; Mitochondria, Heart - enzymology; Myocardial Reperfusion Injury - enzymology; Myocardial Reperfusion Injury - physiopathology; Physiology; Proteins; Rats; Rats, Wistar; Rodents
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.90537.2008

Departments of 1 Anesthesiology and 2 Physiology, Academic Medical Center, Amsterdam, The Netherlands; and 3 Department of Biology, University of Istanbul, Istanbul, Turkey Submitted 17 April 2008 ; accepted in final form 18 February 2009 The glycolytic enzyme hexokinase (HK) is suggested to play a role in ischemic preconditioning (IPC). In the present study we determined how ischemic preconditioning affects HK activity and HKI and HKII protein content at five different time points and three different subcellular fractions throughout cardiac ischemia-reperfusion. Isolated Langendorff-perfused rat hearts (10 groups of 7 hearts each) were subjected to 35 min ischemia and 30 min reperfusion (control groups); the IPC groups were pretreated with 3 times 5-min ischemia. IPC was without effect on microsomal HK activity, and only decreased cytosolic HK activity at 35 min ischemia, which was mimicked by decreased cytosolic HKII, but not HKI, protein content. In contrast, mitochondrial HK activity at baseline and during reperfusion was elevated by IPC, without changes during ischemia. No effect of IPC on mitochondrial HK I protein content was observed. However, mitochondrial HK II protein content during reperfusion was augmented by IPC, albeit not following the IPC stimulus. It is concluded that IPC results in decreased cytosolic HK activity during ischemia that could be explained by decreased HKII protein content. IPC increased mitochondrial HK activity before ischemia and during reperfusion that was only mimicked by increased HK II protein content during reperfusion. IPC was without effect on the phosphorylation status of HK before ischemia. We conclude that IPC is associated with 1 ) a biphasic response of increased mitochondrial HK activity before and after ischemia, 2 ) decreased cytosolic HK activity during ischemia, and 3 ) cellular redistribution of HKII but not HKI. myocardial infarction; permeability transition pore; cardioprotection; compartmentation Address for reprint requests and other correspondence: C. J. Zuurbier, Dept. of Anaesthesiology, Academic Medical Centre, Univ. of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands (e-mail: c.j.zuurbier{at}amc.uva.nl )