scholarly journals Caspase-mediated loss of mitochondrial function and generation of reactive oxygen species during apoptosis

2003 ◽  
Vol 160 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Jean-Ehrland Ricci ◽  
Roberta A. Gottlieb ◽  
Douglas R. Green
Keyword(s):  
Reactive Oxygen Species ◽  
Oxygen Consumption ◽  
Electron Transport ◽  
Cytochrome C ◽  
Mitochondrial Function ◽  
Complex I ◽  
Caspase 3 ◽  
Reactive Oxygen ◽  
Complex Iii ◽  
Oxygen Species

During apoptosis, the permeabilization of the mitochondrial outer membrane allows the release of cytochrome c, which induces caspase activation to orchestrate the death of the cell. Mitochondria rapidly lose their transmembrane potential (ΔΨm) and generate reactive oxygen species (ROS), both of which are likely to contribute to the dismantling of the cell. Here we show that both the rapid loss of ΔΨm and the generation of ROS are due to the effects of activated caspases on mitochondrial electron transport complexes I and II. Caspase-3 disrupts oxygen consumption induced by complex I and II substrates but not that induced by electron transfer to complex IV. Similarly, ΔΨm generated in the presence of complex I or II substrates is disrupted by caspase-3, and ROS are produced. Complex III activity measured by cytochrome c reduction remains intact after caspase-3 treatment. In apoptotic cells, electron transport and oxygen consumption that depends on complex I or II was disrupted in a caspase-dependent manner. Our results indicate that after cytochrome c release the activation of caspases feeds back on the permeabilized mitochondria to damage mitochondrial function (loss of ΔΨm) and generate ROS through effects of caspases on complex I and II in the electron transport chain.

scholarly journals Complex I-mediated reactive oxygen species generation: modulation by cytochrome c and NAD(P)+ oxidation–reduction state

2002 ◽  
Vol 368 (2) ◽  
pp. 545-553 ◽  
Author(s):  
Yulia KUSHNAREVA ◽  
Anne N. MURPHY ◽  
Alexander ANDREYEV
Keyword(s):  
Reactive Oxygen Species ◽  
Cytochrome C ◽  
Complex I ◽  
Electron Flow ◽  
Reactive Oxygen ◽  
Complex Iii ◽  
Ros Generation ◽  
Ros Production ◽  
Oxygen Species ◽  
Reduced State

Several lines of evidence indicate that mitochondrial reactive oxygen species (ROS) generation is the major source of oxidative stress in the cell. It has been shown that ROS production accompanies cytochrome c release in different apoptotic paradigms, but the site(s) of ROS production remain obscure. In the current study, we demonstrate that loss of cytochrome c by mitochondria oxidizing NAD+-linked substrates results in a dramatic increase of ROS production and respiratory inhibition. This increased ROS production can be mimicked by rotenone, a complex I inhibitor, as well as other chemical inhibitors of electron flow that act further downstream in the electron transport chain. The effects of cytochrome c depletion from mitoplasts on ROS production and respiration are reversible upon addition of exogenous cytochrome c. Thus in these models of mitochondrial injury, a primary site of ROS generation in both brain and heart mitochondria is proximal to the rotenone inhibitory site, rather than in complex III. ROS production at complex I is critically dependent upon a highly reduced state of the mitochondrial NAD(P)+ pool and is achieved upon nearly complete inhibition of the respiratory chain. Redox clamp experiments using the acetoacetate/d-β-hydroxybutyrate couple in the presence of a maximally inhibitory rotenone concentration suggest that the site is approx. 50mV more electronegative than the NADH/NAD+ couple. In the absence of inhibitors, this highly reduced state of mitochondria can be induced by reverse electron flow from succinate to NAD+, accounting for profound ROS production in the presence of succinate. These results lead us to propose a model of thermodynamic control of mitochondrial ROS production which suggests that the ROS-generating site of complex I is the Fe—S centre N-1a.

Ascorbic acid improves mitochondrial function in liver of arsenic-treated rat

2010 ◽  
Vol 26 (5) ◽  
pp. 265-272 ◽  
Author(s):  
Sohini Singh ◽  
Suresh Vir Singh Rana
Keyword(s):  
Reactive Oxygen Species ◽  
Ascorbic Acid ◽  
Mitochondrial Function ◽  
Caspase 3 ◽  
Succinic Dehydrogenase ◽  
Reactive Oxygen ◽  
Ultrastructural Changes ◽  
Arsenic Toxicity ◽  
Oxygen Species

Arsenic is an ubiquitous and well-documented carcinogenic metalloid. The most common source of arsenic is drinking water. The mechanism of arsenic toxicity in a cell has historically been centered around its inhibitory effects on cellular respiration and mitochondrial injury. Ascorbic acid, a low molecular weight, water-soluble antioxidant, improves the reduced glutathione (GSH) status by recycling oxidized glutathione. Ascorbic acid can improve mitochondrial function by improving the thiol status; thereby preventing reactive oxygen species— mediated damage to liver as well as kidney. Ascorbic acid has been shown to protect membrane and other cellular compartments by regenerating vitamin E. Therefore, ascorbic acid seems to be a suitable protective factor against arsenic toxicity. Present reports describe the effect of ascorbic acid on oxidative phosphorylation, adenosine triphosphatase (ATPase), succinic dehydrogenase, caspase-3 and apoptosis in the liver of rats treated with arsenic trioxide (AsIII). Ultrastructural changes in the mitochondria have also been reported. We show that cotreatments with ascorbic acid and AsIII improve mitochondrial structure and function. We attribute these improvements mainly to antioxidative role of ascorbic acid. Apoptosis was restricted due to caspase-3 inhibition. Ascorbic acid could protect DNA from the attack of reactive oxygen species generated by AsIII. Consequently its events led to improved ADP:O ratio, normalized ATPase activity and restored the activity of succinic dehydrogenase. Overall, results support the protective role of ascorbic acid against As III-induced liver injury.

scholarly journals A Chemogenomic Screen in Saccharomyces cerevisiae Uncovers a Primary Role for the Mitochondria in Farnesol Toxicity and Its Regulation by the Pkc1 Pathway

2006 ◽  
Vol 282 (7) ◽  
pp. 4868-4874 ◽  
Author(s):  
Gregory D. Fairn ◽  
Kendra MacDonald ◽  
Christopher R. McMaster
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Reactive Oxygen Species ◽  
Cell Death ◽  
Electron Transport ◽  
Signaling Pathway ◽  
Electron Transport Chain ◽  
Reactive Oxygen ◽  
Complex Iii ◽  
Oxygen Species ◽  
Transport Chain

The isoprenoid farnesol has been shown to preferentially induce apoptosis in cancerous cells; however, the mode of action of farnesol-induced death is not established. We used chemogenomic profiling using Saccharomyces cerevisiae to probe the core cellular processes targeted by farnesol. This screen revealed 48 genes whose inactivation increased sensitivity to farnesol. The gene set indicated a role for the generation of oxygen radicals by the Rieske iron-sulfur component of complex III of the electron transport chain as a major mediator of farnesol-induced cell death. Consistent with this, loss of mitochondrial DNA, which abolishes electron transport, resulted in robust resistance to farnesol. A genomic interaction map predicted interconnectedness between the Pkc1 signaling pathway and farnesol sensitivity via regulation of the generation of reactive oxygen species. Consistent with this prediction (i) Pkc1, Bck1, and Mkk1 relocalized to the mitochondria upon farnesol addition, (ii) inactivation of the only non-essential and non-redundant member of the Pkc1 signaling pathway, BCK1, resulted in farnesol sensitivity, and (iii) expression of activated alleles of PKC1, BCK1, and MKK1 increased resistance to farnesol and hydrogen peroxide. Sensitivity to farnesol was not affected by the presence of the osmostabilizer sorbitol nor did farnesol affect phosphorylation of the ultimate Pkc1-responsive kinase responsible for controlling the cell wall integrity pathway, Slt2. The data indicate that the generation of reactive oxygen species by the electron transport chain is a primary mechanism by which farnesol kills cells. The Pkc1 signaling pathway regulates farnesol-mediated cell death through management of the generation of reactive oxygen species.

scholarly journals Oxygen Sensitivity of Mitochondrial Reactive Oxygen Species Generation Depends on Metabolic Conditions

2009 ◽  
Vol 284 (24) ◽  
pp. 16236-16245 ◽  
Author(s):  
David L. Hoffman ◽  
Paul S. Brookes
Keyword(s):  
Reactive Oxygen Species ◽  
Electron Transfer ◽  
Complex I ◽  
Reactive Oxygen ◽  
Complex Iii ◽  
Ros Generation ◽  
Oxygen Species ◽  
Quinone Oxidoreductase ◽  
Electron Transfer Flavoprotein ◽  
Metabolic Conditions

The mitochondrial generation of reactive oxygen species (ROS) plays a central role in many cell signaling pathways, but debate still surrounds its regulation by factors, such as substrate availability, [O2] and metabolic state. Previously, we showed that in isolated mitochondria respiring on succinate, ROS generation was a hyperbolic function of [O2]. In the current study, we used a wide variety of substrates and inhibitors to probe the O2 sensitivity of mitochondrial ROS generation under different metabolic conditions. From such data, the apparent Km for O2 of putative ROS-generating sites within mitochondria was estimated as follows: 0.2, 0.9, 2.0, and 5.0 μm O2 for the complex I flavin site, complex I electron backflow, complex III QO site, and electron transfer flavoprotein quinone oxidoreductase of β-oxidation, respectively. Differential effects of respiratory inhibitors on ROS generation were also observed at varying [O2]. Based on these data, we hypothesize that at physiological [O2], complex I is a significant source of ROS, whereas the electron transfer flavoprotein quinone oxidoreductase may only contribute to ROS generation at very high [O2]. Furthermore, we suggest that previous discrepancies in the assignment of effects of inhibitors on ROS may be due to differences in experimental [O2]. Finally, the data set (see supplemental material) may be useful in the mathematical modeling of mitochondrial metabolism.

Attenuation of Mitochondrial Respiration by Sevoflurane in Isolated Cardiac Mitochondria Is Mediated in Part by Reactive Oxygen Species

2004 ◽  
Vol 100 (3) ◽  
pp. 498-505 ◽  
Author(s):  
Matthias L. Riess ◽  
Janis T. Eells ◽  
Leo G. Kevin ◽  
Amadou K. S. Camara ◽  
Michele M. Henry ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Electron Transport ◽  
Complex I ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Cardiac Mitochondria ◽  
Reactive Oxygen Species Formation ◽  
Complex Ii ◽  
Anesthetic Preconditioning ◽  
Species Formation

Background Anesthetic preconditioning protects against cardiac ischemia/reperfusion injury. Increases in reduced nicotinamide adenine dinucleotide and reactive oxygen species during sevoflurane exposure suggest attenuated mitochondrial electron transport as a trigger of anesthetic preconditioning. The authors investigated the effects of sevoflurane on respiration in isolated cardiac mitochondria. Methods Mitochondria were isolated from fresh guinea pig hearts, and mitochondrial oxygen consumption was measured in the presence of complex I (pyruvate) or complex II (succinate) substrates. The mitochondria were exposed to 0, 0.13, 0.39, 1.3, or 3.9 mM sevoflurane. State 3 respiration was determined after adenosine diphosphate addition. The reactive oxygen species scavengers manganese(III) tetrakis (4-benzoic acid) porphyrin chloride and N-tert-Butyl-a-(2-sulfophenyl)nitrone sodium (10 microM each), or the K(ATP) channel blockers glibenclamide (2 microM) or 5-hydroxydecanoate (300 microM), were given alone or before 1.3 mM sevoflurane. Results Sevoflurane attenuated respiration for both complex I and complex II substrates, depending on the dose. Glibenclamide and 5-hydroxydecanoate had no effect on this attenuation. Both scavengers, however, abolished the sevoflurane-induced attenuation for complex I substrates, but not for complex II substrates. Conclusion The findings suggest that sevoflurane-induced attenuation of complex I is mediated by reactive oxygen species, whereas attenuation of other respiratory complexes is mediated by a different mechanism. The opening of mitochondrial K(ATP) channels by sevoflurane does not seem to be involved in this effect. Thus, reactive oxygen species formation may not only result from attenuated electron transport by sevoflurane, but it may also contribute to complex I attenuation, possibly leading to a positive feedback and amplification of sevoflurane-induced reactive oxygen species formation in triggering anesthetic preconditioning.

scholarly journals Physiologic Implications of Reactive Oxygen Species Production by Mitochondrial Complex I Reverse Electron Transport

Antioxidants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 285 ◽  
Author(s):  
John O. Onukwufor ◽  
Brandon J. Berry ◽  
Andrew P. Wojtovich
Keyword(s):  
Reactive Oxygen Species ◽  
Electron Transport ◽  
Complex I ◽  
Reactive Oxygen ◽  
Reverse Direction ◽  
Mitochondrial Complex I ◽  
Ros Production ◽  
Oxygen Species ◽  
Mitochondrial Complex ◽  
Reverse Electron Transport

Mitochondrial reactive oxygen species (ROS) can be either detrimental or beneficial depending on the amount, duration, and location of their production. Mitochondrial complex I is a component of the electron transport chain and transfers electrons from NADH to ubiquinone. Complex I is also a source of ROS production. Under certain thermodynamic conditions, electron transfer can reverse direction and reduce oxygen at complex I to generate ROS. Conditions that favor this reverse electron transport (RET) include highly reduced ubiquinone pools, high mitochondrial membrane potential, and accumulated metabolic substrates. Historically, complex I RET was associated with pathological conditions, causing oxidative stress. However, recent evidence suggests that ROS generation by complex I RET contributes to signaling events in cells and organisms. Collectively, these studies demonstrate that the impact of complex I RET, either beneficial or detrimental, can be determined by the timing and quantity of ROS production. In this article we review the role of site-specific ROS production at complex I in the contexts of pathology and physiologic signaling.

scholarly journals Atractylenolide I alleviates ischemia/reperfusion injury by preserving mitochondrial function and inhibiting caspase-3 activity

2021 ◽  
Vol 49 (2) ◽  
pp. 030006052199331
Author(s):  
Caiqin Sun ◽  
Xuesong Zhang ◽  
Fei Yu ◽  
Chen Liu ◽  
Fangbin Hu ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Flow Cytometry ◽  
Mitochondrial Function ◽  
Caspase 3 ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
B Cell Lymphoma ◽  
Oxygen Species ◽  
Atractylenolide I ◽  
Hypoxia Reoxygenation

Objective Myocardial ischemia/reperfusion (I/R) injury causes various severe heart diseases, including myocardial infarction. This study aimed to determine the therapeutic effect of atractylenolide I (ATR-I), which is an active ingredient isolated from Atractylodes macrocephala, on myocardial I/R injury. Methods Male Sprague-Dawley rats were randomly allocated to the five following groups (nine rats/group): control, I/R, and I/R + ATR-I preconditioning (10, 50, and 250 µg). The effects of ATR-I on rats with I/R injury were verified in cardiomyocytes with hypoxia/reoxygenation. Production of reactive oxygen species was determined. The proliferative ability of cardiomyocytes was detected using the bromodeoxyuridine assay. Mitochondrial membrane potential was measured using flow cytometry. Cellular apoptosis was assessed by flow cytometry and the terminal dUTP‐digoxigenin nick end labeling assay. Results I/R and hypoxia/reoxygenation injury increased mitochondrial dysfunction and activated caspase-3 and Bax/B cell lymphoma 2 expression in vitro and in vivo. ATR-I pretreatment dose-dependently significantly attenuated myocardial apoptosis and suppressed oxidative stress as reflected by increased mitochondrial DNA copy number and superoxide dismutase activity, and decreased reactive oxygen species and Ca2+ content. Conclusion ATR-I protects against I/R injury by protecting mitochondrial function and inhibiting activation of caspase-3.

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