Reactive oxygen species affect mitochondrial electron transport complex I activity through oxidative cardiolipin damage

Background Reactive oxygen species (ROS) mediate the effects of anesthetic precondition to protect against ischemia and reperfusion injury, but the mechanisms of ROS generation remain unclear. In this study, the authors investigated if mitochondria-targeted antioxidant (mitotempol) abolishes the cardioprotective effects of anesthetic preconditioning. Further, the authors investigated the mechanism by which isoflurane alters ROS generation in isolated mitochondria and submitochondrial particles. Methods Rats were pretreated with 0.9% saline, 3.0 mg/kg mitotempol in the absence or presence of 30 min exposure to isoflurane. Myocardial infarction was induced by left anterior descending artery occlusion for 30 min followed by reperfusion for 2 h and infarct size measurements. Mitochondrial ROS production was determined spectrofluorometrically. The effect of isoflurane on enzymatic activity of mitochondrial respiratory complexes was also determined. Results Isoflurane reduced myocardial infarct size (40 ± 9% = mean ± SD) compared with control experiments (60 ± 4%). Mitotempol abolished the cardioprotective effects of anesthetic preconditioning (60 ± 9%). Isoflurane enhanced ROS generation in submitochondrial particles with nicotinamide adenine dinucleotide (reduced form), but not with succinate, as substrate. In intact mitochondria, isoflurane enhanced ROS production in the presence of rotenone, antimycin A, or ubiquinone when pyruvate and malate were substrates, but isoflurane attenuated ROS production when succinate was substrate. Mitochondrial respiratory experiments and electron transport chain complex assays revealed that isoflurane inhibited only complex I activity. Conclusions The results demonstrated that isoflurane produces ROS at complex I and III of the respiratory chain via the attenuation of complex I activity. The action on complex I decreases unfavorable reverse electron flow and ROS release in myocardium during reperfusion.

Download Full-text

Diphenyleneiodonium acutely inhibits reactive oxygen species production by mitochondrial complex I during reverse, but not forward electron transport

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/j.bbabio.2008.03.005 ◽

2008 ◽

Vol 1777 (5) ◽

pp. 397-403 ◽

Cited By ~ 74

Author(s):

Adrian J. Lambert ◽

Julie A. Buckingham ◽

Helen M. Boysen ◽

Martin D. Brand

Keyword(s):

Reactive Oxygen Species ◽

Electron Transport ◽

Complex I ◽

Reactive Oxygen Species Production ◽

Reactive Oxygen ◽

Mitochondrial Complex I ◽

Oxygen Species ◽

Mitochondrial Complex ◽

Species Production

Download Full-text

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

Anesthesiology ◽

10.1097/00000542-200403000-00007 ◽

2004 ◽

Vol 100 (3) ◽

pp. 498-505 ◽

Cited By ~ 48

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.

Download Full-text

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

Antioxidants ◽

10.3390/antiox8080285 ◽

2019 ◽

Vol 8 (8) ◽

pp. 285 ◽

Cited By ~ 11

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.

Download Full-text

Dicarboxylate carrier-mediated glutathione transport is essential for reactive oxygen species homeostasis and normal respiration in rat brain mitochondria

AJP Cell Physiology ◽

10.1152/ajpcell.00058.2010 ◽

2010 ◽

Vol 299 (2) ◽

pp. C497-C505 ◽

Cited By ~ 29

Author(s):

Christelle K. Kamga ◽

Shelley X. Zhang ◽

Yang Wang

Keyword(s):

Reactive Oxygen Species ◽

Complex I ◽

Reactive Oxygen ◽

Brain Mitochondria ◽

Basal Respiration ◽

Oxygen Species ◽

Ros Homeostasis ◽

Mitochondrial Glutathione ◽

Complex I Activity ◽

Glutathione Transport

Glutathione transport into mitochondria is mediated by oxoglutarate (OGC) and dicarboxylate carrier (DIC) in the kidney and liver. However, transport mechanisms in brain mitochondria are unknown. We found that both carriers were expressed in the brain. Using cortical mitochondria incubated with physiological levels of glutathione, we found that butylmalonate, a DIC inhibitor, reduced mitochondrial glutathione to levels similar to those seen in mitochondria incubated without extramitochondrial glutathione (59% of control). In contrast, phenylsuccinate, an OGC inhibitor, had no effect (97% of control). Additional experiments with DIC and OGC short hairpin RNA in neuronal-like PC12 cells resulted in similar findings. Significantly, DIC inhibition resulted in increased reactive oxygen species (ROS) content in and H2O2 release from mitochondria. It also led to decreased membrane potential, increased basal respiration rates, and decreased phosphorus-to-oxygen (P/O) ratios, especially when electron transport was initiated from complex I. Accordingly, we found that DIC inhibition impaired complex I activity, but not those for complexes II and III. This impairment was not associated with dislodgment of complex subunits. These results suggest that DIC is the main glutathione transporter in cortical mitochondria and that DIC-mediated glutathione transport is essential for these mitochondria to maintain ROS homeostasis and normal respiratory functions.

Download Full-text

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

The Journal of Cell Biology ◽

10.1083/jcb.200208089 ◽

2003 ◽

Vol 160 (1) ◽

pp. 65-75 ◽

Cited By ~ 338

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.

Download Full-text