Ischemic preconditioning affects hexokinase activity and HKII in different subcellular compartments throughout cardiac ischemia-reperfusion
Ischemic preconditioning affects hexokinase activity and HKII in different subcellular compartments throughout cardiac ischemia-reperfusion
复制标题
DOI：
10.1152/japplphysiol.90537.2008
复制
发表时间：
2009-06-01
影响因子：
3.3
通讯作者：
Zuurbier, Coert J.
中科院分区：
文献类型：
--
作者：
Guerel, Ebru;Smeele, Kirsten M.;Zuurbier, Coert J.
E，Smeele Km，Eerbeek O，Koeman A，Demirci C，Hollmann MW，Zuurbier CJ。缺血预适应在整个心脏缺血再灌流过程中影响不同亚细胞室的己糖激酶活性和HKII。应用生理学杂志106：1909-1916,2009。首次发表于2009年2月19日；DOI：10.1152/japplPhysiol.90537.2008。-糖酵解酶己糖激酶(HK)被建议在缺血预适应(IPC)中发挥作用。在本研究中，我们测定了缺血预适应对心肌缺血-再灌流过程中五个不同时间点和三个不同亚细胞部分的HK活性、HKI和HKII蛋白含量的影响。大鼠离体心(10组，每组7只)分别进行35min缺血和30min再灌流(对照组)，IPC组预先给予3次5min的缺血。IPC对微粒体HK活性无影响，仅在缺血35min时胞浆HK活性降低，胞浆HKII蛋白含量下降，但HKI蛋白含量无明显变化。相比之下，缺血前和再灌流时线粒体HK活性均升高，而缺血时无明显变化。IPC对线粒体HK I蛋白含量无明显影响。然而，IPC可使再灌流期间线粒体HK II蛋白含量增加，但不受IPC刺激的影响。结论：缺血时IPC导致胞浆HK活性降低，其原因可能与HKII蛋白含量降低有关。IPC在缺血前和再灌注期均可使线粒体HK活性升高，其作用仅与再灌注期HK II蛋白含量增加相类似。缺血前IPC对HK的磷酸化状态无影响。我们得出结论：IPC与1)缺血前后线粒体HK活性升高的双相反应有关，2)缺血时胞浆HK活性降低，3)HKII而不是HKI的细胞重新分布。
Gurel E, Smeele KM, Eerbeek O, Koeman A, Demirci C, Hollmann MW, Zuurbier CJ. Ischemic preconditioning affects hexokinase activity and HKII in different subcellular compartments throughout cardiac ischemia-reperfusion. J Appl Physiol 106: 1909-1916, 2009. First published February 19, 2009; doi:10.1152/japplphysiol.90537.2008.-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.