scholarly journals How mitochondria produce reactive oxygen species

2008 ◽  
Vol 417 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Michael P. Murphy
Keyword(s):  
Reactive Oxygen Species ◽  
Oxidative Damage ◽  
Oxygen Species ◽  
Mitochondrial Matrix ◽  
Redox Signalling ◽  
Isolated Mitochondria ◽  
Mitochondrial Ros ◽  
Mammalian Mitochondria ◽  
O2 Production

The production of ROS (reactive oxygen species) by mammalian mitochondria is important because it underlies oxidative damage in many pathologies and contributes to retrograde redox signalling from the organelle to the cytosol and nucleus. Superoxide (O2•−) is the proximal mitochondrial ROS, and in the present review I outline the principles that govern O2•− production within the matrix of mammalian mitochondria. The flux of O2•− is related to the concentration of potential electron donors, the local concentration of O2 and the second-order rate constants for the reactions between them. Two modes of operation by isolated mitochondria result in significant O2•− production, predominantly from complex I: (i) when the mitochondria are not making ATP and consequently have a high Δp (protonmotive force) and a reduced CoQ (coenzyme Q) pool; and (ii) when there is a high NADH/NAD+ ratio in the mitochondrial matrix. For mitochondria that are actively making ATP, and consequently have a lower Δp and NADH/NAD+ ratio, the extent of O2•− production is far lower. The generation of O2•− within the mitochondrial matrix depends critically on Δp, the NADH/NAD+ and CoQH2/CoQ ratios and the local O2 concentration, which are all highly variable and difficult to measure in vivo. Consequently, it is not possible to estimate O2•− generation by mitochondria in vivo from O2•−-production rates by isolated mitochondria, and such extrapolations in the literature are misleading. Even so, the description outlined here facilitates the understanding of factors that favour mitochondrial ROS production. There is a clear need to develop better methods to measure mitochondrial O2•− and H2O2 formation in vivo, as uncertainty about these values hampers studies on the role of mitochondrial ROS in pathological oxidative damage and redox signalling.

scholarly journals Ultraendurance exercise increases the production of reactive oxygen species in isolated mitochondria from human skeletal muscle

2010 ◽  
Vol 108 (4) ◽  
pp. 780-787 ◽  
Author(s):  
Kent Sahlin ◽  
Irina G. Shabalina ◽  
C. Mikael Mattsson ◽  
Linda Bakkman ◽  
Maria Fernström ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Oxidative Damage ◽  
Vastus Lateralis ◽  
Reactive Oxygen ◽  
Ros Production ◽  
Oxygen Species ◽  
Work Intensity ◽  
Isolated Mitochondria ◽  
Mitochondrial Ros

Exercise-induced oxidative stress is important for the muscular adaptation to training but may also cause muscle damage. We hypothesized that prolonged exercise would increase mitochondrial production of reactive oxygen species (ROS) measured in vitro and that this correlates with oxidative damage. Eight male athletes (24–32 yr) performed ultraendurance exercise (kayaking/running/cycling) with an average work intensity of 55% V̇o2peak for 24 h. Muscle biopsies were taken from vastus lateralis before exercise, immediately after exercise, and after 28 h of recovery. The production of H2O2 was measured fluorometrically in isolated mitochondria with the Amplex red and peroxidase system. Succinate-supported mitochondrial H2O2 production was significantly increased after exercise (73% higher, P = 0.025) but restored to the initial level at recovery. Plasma level of free fatty acids (FFA) increased fourfold and exceeded 1.2 mmol/l during the last 6 h of exercise. Plasma FFA at the end of exercise was significantly correlated to mitochondrial ROS production ( r = 0.74, P < 0.05). Mitochondrial content of 4-hydroxy-nonenal-adducts (a marker of oxidative damage) was increased only after recovery and was not correlated with mitochondrial ROS production. Total thiol group level and glutathione peroxidase activity were elevated after recovery. In conclusion, ultraendurance exercise increases ROS production in isolated mitochondria, but this is reversed after 28 h recovery. Mitochondrial ROS production was not correlated with oxidative damage of mitochondrial proteins, which was increased at recovery but not immediately after exercise.

scholarly journals Mitochondrial reactive oxygen species regulate the temporal activation of nuclear factor κB to modulate tumour necrosis factor-induced apoptosis: evidence from mitochondria-targeted antioxidants

2005 ◽  
Vol 389 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Gillian HUGHES ◽  
Michael P. MURPHY ◽  
Elizabeth C. LEDGERWOOD
Keyword(s):  
Reactive Oxygen Species ◽  
Transcription Factor ◽  
Tumour Necrosis ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Oxygen Species ◽  
Mitochondrial Matrix ◽  
Mitochondrial Ros ◽  
Induced Apoptosis ◽  
Necrosis Factor

ROS (reactive oxygen species) from mitochondrial and non-mitochondrial sources have been implicated in TNFα (tumour necrosis factor α)-mediated signalling. In the present study, a new class of specific mitochondria-targeted antioxidants were used to explore directly the role of mitochondrial ROS in TNF-induced apoptosis. MitoVit E {[2-(3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2-yl)ethyl]triphenylphosphonium bromide} (vitamin E attached to a lipophilic cation that facilitates accumulation of the antioxidant in the mitochondrial matrix) enhanced TNF-induced apoptosis of U937 cells. In time course analyses, cleavage and activation of caspase 8 in response to TNF were not affected by MitoVit E, whereas the activation of caspase 3 was significantly increased. Furthermore, there was an increased cleavage of the proapoptotic Bcl-2 family member Bid and an increased release of cytochrome c from mitochondria, in cells treated with TNF in the presence of MitoVit E. We considered several mechanisms by which MitoVit E might accelerate TNF-induced apoptosis including mitochondrial integrity (ATP/ADP levels and permeability transition), alterations in calcium homoeostasis and transcription factor activation. Of these, only the transcription factor NF-κB (nuclear factor κB) was implicated. TNF caused maximal nuclear translocation of NF-κB within 15 min, compared with 1 h in cells pretreated with MitoVit E. Thus the accumulation of an antioxidant within the mitochondrial matrix enhances TNF-induced apoptosis by decreasing or delaying the expression of the protective antiapoptotic proteins. These results demonstrate that mitochondrial ROS production is a physiologically relevant component of the TNF signal-transduction pathway during apoptosis, and reveal a novel functional role for mitochondrial ROS as a temporal regulator of NF-κB activation and NF-κB-dependent antiapoptotic signalling.

scholarly journals Protein-L-isoaspartate O-methyltransferase is required for in vivo control of oxidative damage in red blood cells

Haematologica ◽  
2020 ◽  
pp. 0-0
Author(s):  
Angelo D’Alessandro ◽  
Ariel Hay ◽  
Monika Dzieciatkowska ◽  
Benjamin C. Brown ◽  
Evan J Morrison ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Oxidative Damage ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Reactive Oxygen ◽  
Metabolic Reprogramming ◽  
Oxygen Species ◽  
Common Amino Acid

Red blood cells have the special challenge of a large amount of reactive oxygen species (from their substantial iron load and Fenton reactions) combined with the inability to synthesize new gene products. Considerable progress has been made in elucidating the multiple pathways by which red blood cells neutralize reactive oxygen species via NADPH driven redox reactions. However, far less is known about how red blood cells repair the inevitable damage that does occur when reactive oxygen species break through anti-oxidant defenses. When structural and functional proteins become oxidized, the only remedy available to red blood cells is direct repair of the damaged molecules, as red blood cells cannot synthesize new proteins. Amongst the most common amino acid targets of oxidative damage is the conversion of asparagine and aspartate side chains into a succinimidyl group through deamidation or dehydration, respectively. Red blood cells express an L-Isoaspartyl methyltransferase (PIMT, gene name PCMT1) that can convert succinimidyl groups back to an aspartate. Herein, we report that deletion of PCMT1 significantly alters red blood cell metabolism in a healthy state, but does not impair the circulatory lifespan of red blood cells. Through a combination of genetic ablation, bone marrow transplantation and oxidant stimulation with phenylhydrazine in vivo or blood storage ex vivo, we use omics approaches to show that, when animals are exposed to oxidative stress, red blood cells from PCMT1 knockout undergo significant metabolic reprogramming and increased hemolysis. This is the first report of an essential role of PCMT1 for normal RBC circulation during oxidative stress.

Mitochondrial [dys]function; culprit in pre-eclampsia?

2016 ◽  
Vol 130 (14) ◽  
pp. 1179-1184 ◽  
Author(s):  
Cathal Michael McCarthy ◽  
Louise Clare Kenny
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Mitochondrial Dysfunction ◽  
Vascular Dysfunction ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Redox Signalling ◽  
Mitochondrial Superoxide ◽  
Mitochondrial Ros ◽  
Signalling Systems

Mitochondria are extensively identified for their bioenergetic capacities; however, recently these metabolic hubs are increasingly being appreciated as critical regulators of numerous cellular signalling systems. Mitochondrial reactive oxygen species have evolved as a mode of cross-talk between mitochondrial function and physiological systems, to sustain equipoise and foster adaption to cellular stress. Redox signalling mediated by exaggerated mitochondrial-ROS (reactive oxygen species) has been incriminated in a plethora of disease pathologies. Excessive production of mitochondrial ROS is intrinsically linked to mitochondrial dysfunction. Furthermore, mitochondrial dysfunction is a key facilitator of oxidative stress, inflammation, apoptosis and metabolism. These are key pathogenic intermediaries of pre-eclampsia, hence we hypothesize that mitochondrial dysfunction is a pathogenic mediator of oxidative stress in the pathophysiology of pre-eclampsia. We hypothesize that mitochondrial-targeted antioxidants may restrain production of ROS-mediated deleterious redox signalling pathways. If our hypothesis proves correct, therapeutic strategies directly targeting mitochondrial superoxide scavenging should be actively pursued as they may alleviate maternal vascular dysfunction and dramatically improve maternal and fetal health worldwide.

scholarly journals The mystery of reactive oxygen species derived from cell respiration.

2004 ◽  
Vol 51 (1) ◽  
pp. 223-229 ◽  
Author(s):  
Hans Nohl ◽  
Lars Gille ◽  
Katrin Staniek
Keyword(s):  
Reactive Oxygen Species ◽  
Mitochondrial Respiration ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Cell Respiration ◽  
Detection Systems ◽  
Isolated Mitochondria ◽  
Mitochondrial Ros ◽  
Ros Formation ◽  
Electron Carriers

Mitochondrial respiration is considered to provide reactive oxygen species (ROS) as byproduct of regular electron transfer. Objections were raised since results obtained with isolated mitochondria are commonly transferred to activities of mitochondria in the living cell. High electrogenic membrane potential was reported to trigger formation of mitochondrial ROS involving complex I and III. Suggested bioenergetic parameters, starting ROS formation, widely change with the isolation mode. ROS detection systems generally applied may be misleading due to possible interactions with membrane constituents or electron carriers. Avoiding these problems no conditions reported to transform mitochondrial respiration to a radical source were confirmed. However, changing the physical membrane state affected the highly susceptible interaction of the ubiquinol/bc(1) redox complex such that ROS formation became possible.

Abstract 1383: Mitochondrial Tert Enhances Mitochondria Functions In Vivo by Protecting Mitochondrial DNA Integrity from Oxidative Damage

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Nicole Buechner ◽  
Stefan Dröse ◽  
Sascha Jakob ◽  
Ulrich Brandt ◽  
Joachim Altschmied ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Mitochondrial Dna ◽  
Oxidative Damage ◽  
Molecular Mechanisms ◽  
Heart Function ◽  
Reactive Oxygen ◽  
Lower State ◽  
Oxygen Species ◽  
Mtdna Deletions

Mitochondria are essential for respiration and oxidative phosphorylation. Mitochondrial dysfunction due to aging processes is involved in pathologies and pathogenesis of a series of cardiovascular disorders. New results accumulate showing that the enzyme telomerase with its catalytic subunit telomerase reverse transcriptase (TERT) has a beneficial effect on heart functions. The benefit of short-term running of mice for heart function is dependent on TERT expression. TERT can translocate into the mitochondria and mitochondrial TERT (mtTERT) is protective against stress induced stimuli and binds to mitochondrial DNA (mtDNA). Because mtDNA is highly susceptible to damage produced by reactive oxygen species (ROS) which are generated in close proximity to the respiratory chain, the aim of this study was to determine the functions of mtTERT in vivo and in vitro. Therefore, mitochondria from hearts of adult, 2nd generation TERT-deficient mice (TERT −/−) and wt littermates were isolated and state 3 respiration was measured. Strikingly mitochondria from TERT −/− revealed a significantly lower state 3 respiration (TERTwt: 987 +/− 72 pmol/s*mg vs. TERT−/−: 774 +/− 38 pmol/s*mg, p<0.05, n=5). These results demonstrated that TERT −/− mice have a so far undiscovered heart phenotype. In contrast mitochondria isolated from liver tissues did not show any differences. To get further insights in the molecular mechanisms, we reduced endogenous TERT levels by shRNA and measured mitochondrial reactive oxygen species (mtROS). mtROS were increased after ablation of TERT (scrambled: 4.98 +/− 1.1 % gated vs. shTERT: 2.03 +/−0.7 % gated, p<0.05, n=4). We next determined mtDNA deletions, which are caused by mtROS. Semiquantitative realtime PCR of mtDNA deletions revealed that mtTERT protects mtDNA from oxidative damage. To analyze whether mitochondrial integrity is required to protect from apoptosis, vectors with mitochondrially targeted TERT (mitoTERT) and wildtype TERT (wtTERT) were transfected and apoptosis was measured. mitoTERT showed the most prominent protective effect on H2O2 induced apoptosis. In conclusion, mtTERT has a protective role in mitochondria by importantly contributing to mtDNA integrity and thereby enhancing respiration capacity of the heart.

scholarly journals Icariside II, a Phosphodiesterase-5 Inhibitor, Attenuates Beta-Amyloid-Induced Cognitive Deficits via BDNF/TrkB/CREB Signaling

2018 ◽  
Vol 49 (3) ◽  
pp. 1010-1025 ◽  
Author(s):  
Shuang Liu ◽  
Xiaohui Li ◽  
Jianmei Gao ◽  
Yuangui Liu ◽  
Jingshan Shi ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cognitive Deficits ◽  
Cell Injury ◽  
Intracellular Reactive Oxygen Species ◽  
Oxygen Species ◽  
Mitochondrial Ros ◽  
Icariside Ii ◽  
Underlying Mechanisms ◽  
Phosphodiesterase 5

Background/Aims: Icariside II (ICS II) is an active component from Epimedium brevicornum, a Chinese medicine extensively used in China. Our previous study has proved that ICS II protects against learning and memory impairments and neuronal apoptosis in the hippocampus induced by beta-amyloid25-35 (Aβ25-35) in rats. However, its in-depth underlying mechanisms remain still unclear. Hence this study was designed to explore the potential underlying mechanisms of ICS II by experiments with an in vivo model of Aβ25-35-induced cognitive deficits in rats combined with a neuronal-like PC12 cells injury in vitro model. Methods: The cognitive deficits was measured using Morris water maze test, and apoptosis, intracellular reactive oxygen species (ROS) and mitochondrial ROS levels were detected by TUNEL, DCFH-DA and Mito-SOX staining, respectively. Expression of Bcl-2, Bax, brain derived neurotrophic factor (BDNF), tyrosine receptor kinase B (TrkB), and cAMP response element binding (p-CREB) and active-Caspase 3 levels were evaluated by Western blot. Results: It was found that ICS II, a phosphodiesterase-5 inhibitor, significantly attenuated cognitive deficits caused by Aβ25-35 injection in rats, and ICS II not only significantly enhanced the expression of BDNF and TrkB, but also activated CREB. Furthermore, ICS II also significantly abrogated Aβ25-35-induced PC12 cell injury, and inhibited Aβ25-35-induced intracellular reactive oxygen species (ROS) overproduction, as well as mitochondrial ROS levels. In addition, ICS II up-regulated the expressions of BDNF and TrkB consistent with the findings in vivo. ANA-12, a TrkB inhibitor, blocked the neuroprotective effect of ICS II on Aβ25-35-induced neuronal injury. Conclusion: ICS II mitigates Aβ25-35-induced cognitive deficits and neuronal cell injury by upregulating the BDNF/TrkB/CREB signaling, suggesting that ICS II can be used as a potential therapeutic agent for dementia, such as Alzheimer’s disease.

scholarly journals Dual and Opposite Roles of Reactive Oxygen Species (ROS) in Chagas Disease: Beneficial on the Pathogen and Harmful on the Host

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Edio Maldonado ◽  
Diego A. Rojas ◽  
Sebastian Morales ◽  
Vicente Miralles ◽  
Aldo Solari
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Oxidative Damage ◽  
Chagas Disease ◽  
Molecular Mechanisms ◽  
Reactive Oxygen ◽  
Parasite Growth ◽  
Oxygen Species ◽  
Chronic Stage ◽  
Mitochondrial Ros

Chagas disease is a neglected tropical disease, which affects an estimate of 6-7 million people worldwide. Chagas disease is caused by Trypanosoma cruzi, which is a eukaryotic flagellate unicellular organism. At the primary infection sites, these parasites are phagocytized by macrophages, which produce reactive oxygen species (ROS) in response to the infection with T. cruzi. The ROS produce damage to the host tissues; however, macrophage-produced ROS is also used as a signal for T. cruzi proliferation. At the later stages of infection, mitochondrial ROS is produced by the infected cardiomyocytes that contribute to the oxidative damage, which persists at the chronic stage of the disease. The oxidative damage leads to a functional impairment of the heart. In this review article, we will discuss the mechanisms by which T. cruzi is able to deal with the oxidative stress and how this helps the parasite growth at the acute phase of infection and how the oxidative stress affects the cardiomyopathy at the chronic stage of the Chagas disease. We will describe the mechanisms used by the parasite to deal with ROS and reactive nitrogen species (RNS) through the trypanothione and the mechanisms used to repair the damaged DNA. Also, a description of the events produced by ROS at the acute and chronic stages of the disease is presented. Lastly, we discuss the benefits of ROS for T. cruzi growth and proliferation and the possible mechanisms involved in this phenomenon. Hypothesis is put forward to explain the molecular mechanisms by which ROS triggers parasite growth and proliferation and how ROS is able to produce a long persisting damage on cardiomyocytes even in the absence of the parasite.

scholarly journals Mitochondrial Reactive Oxygen Species (ROS) and ROS-Induced ROS Release

2014 ◽  
Vol 94 (3) ◽  
pp. 909-950 ◽  
Author(s):  
Dmitry B. Zorov ◽  
Magdalena Juhaszova ◽  
Steven J. Sollott
Keyword(s):  
Reactive Oxygen Species ◽  
Mitochondrial Permeability Transition ◽  
Physiological Role ◽  
Reactive Oxygen ◽  
Anion Channel ◽  
Oxygen Species ◽  
Redox Stress ◽  
Mitochondrial Ros

Byproducts of normal mitochondrial metabolism and homeostasis include the buildup of potentially damaging levels of reactive oxygen species (ROS), Ca2+, etc., which must be normalized. Evidence suggests that brief mitochondrial permeability transition pore (mPTP) openings play an important physiological role maintaining healthy mitochondria homeostasis. Adaptive and maladaptive responses to redox stress may involve mitochondrial channels such as mPTP and inner membrane anion channel (IMAC). Their activation causes intra- and intermitochondrial redox-environment changes leading to ROS release. This regenerative cycle of mitochondrial ROS formation and release was named ROS-induced ROS release (RIRR). Brief, reversible mPTP opening-associated ROS release apparently constitutes an adaptive housekeeping function by the timely release from mitochondria of accumulated potentially toxic levels of ROS (and Ca2+). At higher ROS levels, longer mPTP openings may release a ROS burst leading to destruction of mitochondria, and if propagated from mitochondrion to mitochondrion, of the cell itself. The destructive function of RIRR may serve a physiological role by removal of unwanted cells or damaged mitochondria, or cause the pathological elimination of vital and essential mitochondria and cells. The adaptive release of sufficient ROS into the vicinity of mitochondria may also activate local pools of redox-sensitive enzymes involved in protective signaling pathways that limit ischemic damage to mitochondria and cells in that area. Maladaptive mPTP- or IMAC-related RIRR may also be playing a role in aging. Because the mechanism of mitochondrial RIRR highlights the central role of mitochondria-formed ROS, we discuss all of the known ROS-producing sites (shown in vitro) and their relevance to the mitochondrial ROS production in vivo.

Mitochondrial reactive oxygen species (ROS) in animal cells: relevance to aging and normal physiology

2014 ◽  
Vol 92 (7) ◽  
pp. 603-613 ◽  
Author(s):  
Ellen L. Robb ◽  
Casey A. Christoff ◽  
Lucas A. Maddalena ◽  
Jeffrey A. Stuart
Keyword(s):  
Reactive Oxygen Species ◽  
Oxidative Damage ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Animal Cells ◽  
Apoptotic Pathway ◽  
Produce Water ◽  
Mitochondrial Ros ◽  
Electron Reduction ◽  
Macromolecular Damage

In animal mitochondria, the four electron reduction of molecular oxygen to produce water at respiratory complex IV is the terminal step in substrate oxidation. However, respiratory complexes I, II, and III can participate in the single electron reduction of oxygen to produce the radical species superoxide. This progenitor reactive oxygen species (ROS) participates in a number of reactions that generate other ROS. These molecules may react with, and damage, intracellular macromolecules, leading to cellular dysfunction. Mitochondrial ROS production is often considered from this perspective of macromolecular damage and is central to the “oxidative damage theory of aging”, which suggests the accumulation of oxidative damage in animal cells underlies the aging phenotype and limits lifespan. In this review, we discuss some experimental results accumulated over the past decade that are inconsistent with this theory. A limitation of the theory is that it presupposes mitochondrial ROS are inherently harmful. However, it is increasingly apparent that some basic cellular functions are physiologically regulated by normal levels of mitochondrial ROS. For example, cell growth and division, the apoptotic pathway, and mitochondrial fusion–fission dynamics all appear to be redox-regulated by mitochondrial ROS and perhaps the matrix manganese superoxide dismutase (MnSOD). Therefore, it is less clear how the balance between ROS regulation of normal cellular activities and ROS-mediated macromolecular damage is maintained and how this relates to aging and longevity in animals.

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