Egr-1, a Central and Unifying Role in Cardioprotection from Ischemia-Reperfusion Injury?
ABSTRACT Our previous studies have shown that N-n-butyl haloperidol iodide (F(2)) can antagonize myocardial ischemia/reperfusion (I/R) injury by blocking intracellular Ca(2+) overload and suppressing Egr-1 overexpression. The present study is to investigate the relation between the reduction of Ca(2+) overload and the inhibition of Egr-1 overexpression.
The Sprague-Dawley rat myocardial I/R model and cultured cardiomyocyte hypoxia-reoxygenation (H/R) model were established. Administration of Egr-1 antisense oligodeoxyribonucleotide (AS-ODN) only or combining with F(2), Egr-1 protein expression was examined by Western-blot analyses. Hemodynamic parameters, creatine kinase (CK) and lactate dehydrogenase (LDH), superoxide dismutase (SOD) and malondialdehyde (MDA), myeloperoxidase (MPO), cardiac troponin I (cTnI), and tumor necrosis factor-alpha (TNF-alpha) were measured to assess the degree of injury and inflammation of myocardial tissues and cells.
Treatment with Egr-1 AS-ODN significantly reduced Egr-1 protein expression and attenuated injury and inflammation of myocardium caused by I/R or H/R evidenced by the amelioration of hemodynamics, the decrease in leakage of CK, LDH, cTnI, the increase in MDA generation, the decrease in SOD activity, the reduction of MPO activity in myocardial tissues and release of TNF-alpha from cultured cardiomyocytes. Treatment with F(2) combined with Egr-1 AS-ODN, the inhibition of Egr-1 protein expression and inflammation (MPO activity and TNF-alpha level) were not enhanced, but the protection from myocardial I/R (or H/R) injury was significantly increased in hemodynamics and cytomembrane permeability relative to the using of Egr-1 AS-ODN only.
These data suggest that the inhibition of Egr-1 overexpression cannot involve all mechanisms of cardioprotection from I/R injury.
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ABSTRACT: One of the leading cause of death in the world is ischemia/reperfusion (I/R) -mediated acute myocardial infarction (AMI).There are a lot of Chinese traditional patent medicines, such as Xin'an Capsules, Xin Xuening Tablet and so on, which have the protective effects on myocardial I/R injury and have been routinely used in treating cardiac diseases for a long time in China. Hyperoside (Hyp) is the chief component of these medicines. This study investigated the action of Hyp in isolated myocardial I/R injury, as well as its possible mechanisms.Using the Langendorff model, isolated Sprague-Dawley rat hearts were subjected to 30min of global ischemia and 50min of reperfusion. Cardiac function was measured, and infarct size was evaluated by triphenyltetrazolium chloride staining at the end of the reperfusion. Coronary effluent was analyzed for lactate dehydrogenase (LDH) and creatine kinase (CK). Myocardium was also measured for the activity of total superoxide dismutase (T-SOD) and the content of Malonaldialdehyde (MDA). Phosphorylation of extracellular signal-regulated protein kinase (ERK) was analyzed by Western blotting.We reported for the first time that administration of Hyp before/ after I/R significantly improved heart contraction and limited the infarct size, CK and LDH leakage from the damaged myocardium after I/R. The activity of SOD and the content of MDA remarkably changed in the presence of Hyp as well. Phosphorylation of ERK was significantly increased in Hyp-treated hearts when compared to controls (p<0.01). Hyp-induced ERK phosphorylation was inhibited by PD98059. We therefore conclude that Hyp can protect cardiomyocytes from I/R-induced oxidative stress through the activation of ERK-dependent signaling.Free Radical Biology and Medicine 01/2013; 57. DOI:10.1016/j.freeradbiomed.2012.12.023 · 5.71 Impact Factor
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ABSTRACT: Despite decades of intensive research, there is still no effective treatment for ischemia/reperfusion (I/R) injury, an important corollary in the treatment of ischemic disease. I/R injury is initiated when the altered biochemistry of cells after ischemia is no longer compatible with oxygenated microenvironment (or reperfusion). To better understand the molecular basis of this alteration and subsequent incompatibility, we assessed the temporal and quantitative alterations in the cardiac proteome of a mouse cardiac I/R model by an iTRAQ approach at 30 min of ischemia, and at 60 or 120 min reperfusion after the ischemia using sham-operated mouse heart as the baseline control. Of the 509 quantified proteins identified, 121 proteins exhibited significant changes (p-value<0.05) over time and were mostly clustered in eight functional groups: Fatty acid oxidation, Glycolysis, TCA cycle, ETC (electron transport chain), Redox Homeostasis, Glutathione S-transferase, Apoptosis related, and Heat Shock proteins. The first four groups are intimately involved in ATP production and the last four groups are known to be important in cellular antioxidant activity. During ischemia and reperfusion, the short supply of oxygen precipitates a pivotal metabolic switch from aerobic metabolism involving fatty acid oxidation, TCA, and phosphorylation to anaerobic metabolism for ATP production and this, in turn, increases reactive oxygen species (ROS) formation. Therefore the implication of these 8 functional groups suggested that ischemia-reperfusion injury is underpinned in part by proteomic alterations. Reversion of these alterations to preischemia levels took at least 60 min, suggesting a refractory period in which the ischemic cells cannot adjust to the presence of oxygen. Therefore, therapeutics that could compensate for these proteomic alterations during this interim refractory period could alleviate ischemia-reperfusion injury to enhance cellular recovery from an ischemic to a normoxic microenvironment. Among the perturbed proteins, Park7 and Ppia were selected for further investigation of their functions under hypoxia. The results show that Park7 plays a key role in regulating antioxidative stress and cell survival, and Ppia may function in coping with the unfolded protein stress in the I/R condition.Journal of Proteome Research 03/2012; 11(4):2331-46. DOI:10.1021/pr201025m · 5.00 Impact Factor
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ABSTRACT: The aim of this paper is to investigate whether Shen-fu injection (SFI), a traditional Chinese medicine, could attenuate myocardial ischemia-reperfusion (MI/R) injury in diabetes. Streptozotocin-induced diabetic rats were randomly assigned to the Sham, I/R, SFI preconditioning, and SFI plus wortmannin (a phosphatidylinositol 3-kinase inhibitor) groups. After the treatment, hearts were subjected to 30 min of coronary artery occlusion and 2 h reperfusion except the Sham group. Myocardial infarct size and cardiomyocytes apoptosis were increased significantly in MI/R group as compared with the Sham group. SFI preconditioning significantly decreased infarct size, apoptosis, caspase-3 protein expression, MDA level in myocardial tissues, and plasma level of CK and LDH but increased p-Akt, p-eNOS, bcl-2 protein expression, and SOD activity compared to I/R group. Moreover, SFI-induced cardioprotection was abolished by wortmannin. We conclude that SFI preconditioning protects diabetic hearts from I/R injury via PI3K/Akt-dependent pathway.BioMed Research International 01/2011; 2011(1110-7243):384627. DOI:10.1155/2011/384627 · 2.71 Impact Factor