scholarly journals Attenuation of oxidant stress during reoxygenation by AMP 579 in cardiomyocytes

2001 ◽  
Vol 281 (6) ◽  
pp. H2585-H2589 ◽  
Author(s):  
Zhelong Xu ◽  
Michael V. Cohen ◽  
James M. Downey ◽  
Terry L. Vanden Hoek ◽  
Zhenhai Yao
Keyword(s):  
Cell Death ◽  
Reperfusion Injury ◽  
Oxidant Stress ◽  
Myocardial Reperfusion ◽  
Ros Generation ◽  
Iodide Uptake ◽  
Simultaneous Exposure ◽  
Embryonic Cardiomyocytes ◽  
Dichlorofluorescin Diacetate ◽  
Reactive Oxidant

AMP 579, an adenosine A1/A2 receptor agonist, has a strong anti-infarct effect when administered just before reperfusion. Because oxidative stress has been proposed to contribute to myocardial reperfusion injury, we tested whether AMP 579 can reduce the production of reactive oxidant species (ROS) during reoxygenation in cultured chick embryonic cardiomyocytes. The intracellular fluorescent probe 2′,7′-dichlorofluorescin diacetate (DCFH) was used to detect ROS. The cells were subjected to 60 min of simulated ischemia, followed by either 15 min or 3 h of reoxygenation. AMP 579 (0.5 and 1 μM), when started 10 min before reoxygenation, significantly reduced ROS generation from 4.86 ± 0.30 (arbitrary units) in untreated cells to 2.72 ± 0.31 and 1.85 ± 0.14, respectively ( P < 0.05). Cell death that was assessed by propidium iodide uptake was markedly reduced by AMP 579 (49.6 ± 4.7% of control cells vs. 25.4 ± 2.4%, P < 0.05). In contrast, adenosine did not alter ROS generation or cell death. Attenuation of ROS production by AMP 579 was completely prevented by simultaneous exposure of cells to the selective adenosine A2 antagonist 8-(13-chlorostyryl) caffeine. These results indicate that AMP 579 directly protects cardiomyocytes from reperfusion injury by a mechanism that attenuates intracellular oxidant stress. Furthermore, adenosine could not duplicate these effects.

Baicalein attenuates oxidant stress in cardiomyocytes

2002 ◽  
Vol 282 (3) ◽  
pp. H999-H1006 ◽  
Author(s):  
Zuo-Hui Shao ◽  
Terry L. Vanden Hoek ◽  
Yimin Qin ◽  
Lance B. Becker ◽  
Paul T. Schumacker ◽  
...  
Keyword(s):  
Cell Death ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Ischemia Reperfusion ◽  
Oxidant Stress ◽  
Complex Iii ◽  
Ros Generation ◽  
Resonance Spectroscopy ◽  
Iodide Uptake ◽  
Simulated Ischemia

Flavonoids within Scutellaria baicalensis may be potent antioxidants on the basis of our studies of S. baicalensis extract. To further this work, we studied the antioxidative effects of baicalein, a flavonoid component of S. baicalensis, in a chick cardiomyocyte model of reactive oxygen species (ROS) generation during hypoxia, simulated ischemia-reperfusion, or mitochondrial complex III inhibition with antimycin A. Oxidant stress was measured by oxidation of the intracellular probes 2′,7′-dichlorofluorescin diacetate and dihydroethidium. Viability was assessed by propidium iodide uptake. Baicalein attenuated oxidant stress during all conditions studied and acted within minutes of treatment. For example, baicalein given only at reperfusion dose dependently attenuated the ROS burst at 5 min after 1 h of simulated ischemia. It also decreased subsequent cell death at 3 h of reperfusion from 52.3 ± 2.5% in untreated cells to 29.4 ± 3.0% (with return of contractions; P < 0.001). In vitro studies using electron paramagnetic resonance spectroscopy with the spin trap 5-methoxycarbonyl-5-methyl-1-pyrroline- N-oxide revealed that baicalein scavenges superoxide but does not mimic the effects of superoxide dismutase. We conclude that baicalein can scavenge ROS generation in cardiomyocytes and that it protects against cell death in an ischemia-reperfusion model when given only at reperfusion.

Reperfusion injury on cardiac myocytes after simulated ischemia

1996 ◽  
Vol 270 (4) ◽  
pp. H1334-H1341 ◽  
Author(s):  
T. L. Vanden Hoek ◽  
Z. Shao ◽  
C. Li ◽  
R. Zak ◽  
P. T. Schumacker ◽  
...  
Keyword(s):  
Cell Death ◽  
Reperfusion Injury ◽  
Cell Injury ◽  
Membrane Damage ◽  
Cardiac Injury ◽  
Cellular Membrane ◽  
Iodide Uptake ◽  
Membrane Injury ◽  
Simulated Ischemia ◽  
Lactate Dehydrogenase Release

The extent of cardiac injury incurred during reperfusion as opposed to that occurring during ischemia is unclear. This study tested the hypothesis that simulated ischemia followed by simulated reperfusion causes significant "reperfusion injury" in isolated chick cardiomyocytes. Cells were exposed to hypoxia, hypercarbic acidosis, hyperkalemia, and substrate deprivation for 1 h followed by 3 h of reperfusion. Irreversible cell membrane injury, measured by propidium iodide uptake, increased from 4% of cells at the end of ischemia to 73% after reperfusion; death occurred in only 17% of cells kept ischemic for 4 h. Lactate dehydrogenase release was consistent with these changes. Lengthening ischemia from 30 to 90 min increased cell injury as expected, but of the total cell death, > 90% occurred during reperfusion. "Chemical hypoxia" composed of cyanide (2.5 mM) plus 2-deoxyglucose augmented injury before reperfusion compared with simulated ischemia. Inhibition of oxygen radical generation by use of metal chelator 1,10-phenanthroline reduced cell death from 73% to 40% after reperfusion (P = 0.001). We conclude that simulated reperfusion significantly augments the cellular membrane damage elicited by simulated ischemia in isolated cardiomyocytes devoid of other factors and suggest that reactive oxygen species, perhaps from the mitochondria, participate in this injury.

Abstract P133: Role of Akt and p38 in Oxidant Stress Injury and Hypothermic Protection in Murine Cardiomyocytes

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Kimberly R Wojcik ◽  
Zuo-Hui Shao ◽  
Chang-Qing Li ◽  
Kimm J Hamann ◽  
Terry L Vanden Hoek
Keyword(s):  
Cell Death ◽  
Cardiac Arrest ◽  
Cell Injury ◽  
Ischemia Reperfusion ◽  
Oxidant Stress ◽  
Ros Generation ◽  
Akt Inhibitor ◽  
Stress Injury ◽  
P38 Inhibitor ◽  
Sb 203580

Cardiac arrest is an ischemia/reperfusion (I/R) disease characterized by oxidant generation, inflammation, and cell death; and hypothermia (HT) has been shown to improve post-cardiac arrest reperfusion injury. We developed a neonatal mouse cardiomyocyte model of I/R (90 min I + 3 hr R) that demonstrates cell injury associated with increased reactive oxygen species (ROS) generation at reperfusion (as measured by DCFH). Mild HT (32°C) protects mouse cardiomyocytes from I/R injury, and we hypothesize that this protection may be related to the activation of the survival kinase Akt. The Akt inhibitor API-2 (10 ìM) reversed HT protection [32.4 ± 7.1% vs 65.7 ± 6.3% with API-2, p< .01(as measured by PI)] to cell death levels commensurate with normothermic I/R injury (60.7 ± 6.0%). Phospho-Akt (pAkt) levels declined during ischemia, and while both Ser473 and Thr308 were phosphorylated in normothermia and HT within 15 min reperfusion, HT showed an augmented level of pAkt at Thr308. Furthermore, this increase was sustained for the first 30 min of reperfusion. To further study this relationship, murine cardiomyocytes were exposed to exogenous H2O2 to mimic the oxidant stress associated with I/R. Mouse cardiomyocytes demonstrated a dose- and time-dependent activation of Akt to H2O2 that showed maximal activation of both the Ser473 and Thr308 sites within 30 min with 200 ìM H2O2. As in I/R-stimulated cells, the Thr308 site declined to near baseline levels within 1 hr while Ser473 remained elevated. Based on recent findings linking Akt and ROS with p38, we examined the effect of I/R and H2O2 on p38. Mouse cardiomyocytes demonstrated a rapid activation of p-p38 (Thr10/Tyr182) in the context of both stresses. Further, we studied the effect of the Akt inhibitor, API-2, as well as the p38 inhibitor, SB 203580, in H2O2-stimulated cells. As in I/R, API-2 blocked H2O2-induced pAkt, but this inhibitor did not have any effect on p-p38. However, when p38 activation was blocked using SB 203580, pAkt levels decreased by 2 hr. These data suggest that HT is, in part, mediated through Akt and that p38 lies upstream of Akt in the context of oxidant stress. These kinases may act as triggers for the initiation of survival pathways in cardiomyocytes to combat potential damage induced by ROS generation.

scholarly journals Mechanisms of cell death in oxidant stress and ischemia‐reperfusion injury

2007 ◽  
Vol 21 (5) ◽  
Author(s):  
Gabriel Loor ◽  
Jyothi Kondapalli ◽  
Bumihka Sharma ◽  
Robert Guzy ◽  
Paul Schumacker
Keyword(s):  
Cell Death ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Oxidant Stress

Na+ overload-induced mitochondrial damage in the ischemic heart

2004 ◽  
Vol 82 (12) ◽  
pp. 1033-1043 ◽  
Author(s):  
Satoshi Takeo ◽  
Kouichi Tanonaka
Keyword(s):  
Cell Death ◽  
Free Radicals ◽  
Reperfusion Injury ◽  
Myocardial Contractility ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ion Homeostasis ◽  
Myocardial Cell ◽  
Myocardial Reperfusion ◽  
Contractile Dysfunction

Ischemia induces a decrease in myocardial contractility that may lead more or less to contractile dysfunction in the heart. When the duration of ischemia is relatively short, myocardial contractility is immediately reversed to control levels upon reperfusion. In contrast, reperfusion induces myocardial cell death when the heart is exposed to a prolonged period of ischemia. This phenomenon is the so-called "reperfusion injury". Numerous investigators have reported the mechanisms underlying myocardial reperfusion injury such as generation of free radicals, disturbance in the intracellular ion homeostasis, and lack of energy for contraction. Despite a variety of investigations concerning the mechanisms for ischemia and ischemia–reperfusion injury, ionic disturbances have been proposed to play an important role in the genesis of the ischemia–reperfusion injury. In this present study, we focused on the contribution of Na+ overload and mitochondrial dysfunction during ischemia to the genesis of this ischemia–reperfusion injury.Key words: mitochondria, myocardial ischemia, Na+ channels, Na+/H+ exchanger, Na+ overload.

scholarly journals Brain-Specific Serine-47 Modification of Cytochrome c Regulates Cytochrome c Oxidase Activity Attenuating ROS Production and Cell Death: Implications for Ischemia/Reperfusion Injury and Akt Signaling

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1843 ◽  
Author(s):  
Hasini A. Kalpage ◽  
Junmei Wan ◽  
Paul T. Morse ◽  
Icksoo Lee ◽  
Maik Hüttemann
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Reperfusion Injury ◽  
Cell Line ◽  
Cytochrome C Oxidase ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ros Generation ◽  
Ros Production ◽  
The Brain

We previously reported that serine-47 (S47) phosphorylation of cytochrome c (Cytc) in the brain results in lower cytochrome c oxidase (COX) activity and caspase-3 activity in vitro. We here analyze the effect of S47 modification in fibroblast cell lines stably expressing S47E phosphomimetic Cytc, unphosphorylated WT, or S47A Cytc. Our results show that S47E Cytc results in partial inhibition of mitochondrial respiration corresponding with lower mitochondrial membrane potentials (ΔΨm) and reduced reactive oxygen species (ROS) production. When exposed to an oxygen-glucose deprivation/reoxygenation (OGD/R) model simulating ischemia/reperfusion injury, the Cytc S47E phosphomimetic cell line showed minimal ROS generation compared to the unphosphorylated WT Cytc cell line that generated high levels of ROS upon reoxygenation. Consequently, the S47E Cytc cell line also resulted in significantly lower cell death upon exposure to OGD/R, confirming the cytoprotective role of S47 phosphorylation of Cytc. S47E Cytc also resulted in lower cell death upon H2O2 treatment. Finally, we propose that pro-survival kinase Akt (protein kinase B) is a likely mediator of the S47 phosphorylation of Cytc in the brain. Akt inhibitor wortmannin abolished S47 phosphorylation of Cytc, while the Akt activator SC79 maintained S47 phosphorylation of Cytc. Overall, our results suggest that loss of S47 phosphorylation of Cytc during brain ischemia drives reperfusion injury through maximal electron transport chain flux, ΔΨm hyperpolarization, and ROS-triggered cell death.

scholarly journals CBIO-07. CELL DEATH INDUCED BY AN OSCILLATING MAGNETIC FIELD IN PATIENT DERIVED GLIOBLASTOMA CELLS IS MEDIATED BY REACTIVE OXYGEN SPECIES

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii17-ii17
Author(s):  
Shashank Hambarde ◽  
Martyn Sharpe ◽  
David Baskin ◽  
Santosh Helekar
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Cell Viability ◽  
Cortical Neurons ◽  
Reactive Oxygen ◽  
Great Promise ◽  
Antioxidant Vitamin ◽  
Ros Generation ◽  
Oxygen Species ◽  
Novel Therapy

Abstract Noninvasive cancer therapy with minimal side effects would be ideal for improving patient outcome in the clinic. We have developed a novel therapy using strong rotating magnets mounted on a helmet. They generate oscillating magnetic fields (OMF) that penetrate through the skull and cover the entire brain. We have demonstrated that OMF can effectively kill patient derived glioblastoma (GBM) cells in cell culture without having cytotoxic effects on cortical neurons and normal human astrocytes (NHA). Exposure of GBM cells to OMF reduced the cell viability by 33% in comparison to sham-treated cells (p&lt; 0.001), while not affecting NHA cell viability. Time lapse video-microscopy for 16 h after OMF exposure showed a marked elevation of mitochondrial reactive oxygen species (ROS), and rapid apoptosis of GBM cells due to activation of caspase 3. Addition of a potent antioxidant vitamin E analog Trolox effectively blocked OMF-induced GBM cell death. Furthermore, OMF significantly potentiated the cytotoxic effect of the pro-oxidant Benzylamine. The results of our studies demonstrate that OMF-induced cell death is mediated by ROS generation. These results demonstrate a potent oncolytic effect on GBM cells that is novel and unrelated to any previously described therapy, including a very different mechanism of action and different technology compared to Optune therapy. The effect is very powerful, and unlike Optune, can be seen within hours after initiation of treatment. We believe that this technology holds great promise for new, effective and nontoxic treatment of glioblastoma.

scholarly journals Ca2+ overload- and ROS-associated mitochondrial dysfunction contributes to δ-tocotrienol-mediated paraptosis in melanoma cells

APOPTOSIS ◽  
2021 ◽  
Author(s):  
Michela Raimondi ◽  
Fabrizio Fontana ◽  
Monica Marzagalli ◽  
Matteo Audano ◽  
Giangiacomo Beretta ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Mitochondrial Dysfunction ◽  
Atp Synthesis ◽  
Melanoma Cells ◽  
Human Melanoma ◽  
Ros Generation ◽  
Therapy Outcomes ◽  
Human Melanoma Cells ◽  
Oxphos Complex

Abstract Melanoma is an aggressive tumor with still poor therapy outcomes. δ-tocotrienol (δ-TT) is a vitamin E derivative displaying potent anti-cancer properties. Previously, we demonstrated that δ-TT triggers apoptosis in human melanoma cells. Here, we investigated whether it might also activate paraptosis, a non-canonical programmed cell death. In accordance with the main paraptotic features, δ-TT was shown to promote cytoplasmic vacuolization, associated with endoplasmic reticulum/mitochondrial dilation and protein synthesis, as well as MAPK activation in A375 and BLM cell lines. Moreover, treated cells exhibited a significant reduced expression of OXPHOS complex I and a marked decrease in oxygen consumption and mitochondrial membrane potential, culminating in decreased ATP synthesis and AMPK phosphorylation. This mitochondrial dysfunction resulted in ROS overproduction, found to be responsible for paraptosis induction. Additionally, δ-TT caused Ca2+ homeostasis disruption, with endoplasmic reticulum-derived ions accumulating in mitochondria and activating the paraptotic signaling. Interestingly, by using both IP3R and VDAC inhibitors, a close cause-effect relationship between mitochondrial Ca2+ overload and ROS generation was evidenced. Collectively, these results provide novel insights into δ-TT anti-melanoma activity, highlighting its ability to induce mitochondrial dysfunction-mediated paraptosis. Graphic Abstract δ-tocotrienol induces paraptotic cell death in human melanoma cells, causing endoplasmic reticulum dilation and mitochondrial swelling. These alterations induce an impairment of mitochondrial function, ROS production and calcium overload.

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