Effects of Matrix pH on Spontaneous Transient Depolarization and Reactive Oxygen Species Production in Mitochondria

Reactive oxygen species (ROS) oxidize surrounding molecules and thus impair their functions. Since mitochondria are a major source of ROS, suppression of ROS overproduction in the mitochondria is important for cells. Spontaneous transient depolarization of individual mitochondria is a physiological phenomenon widely observed from plants to mammals. Mitochondrial uncoupling can reduce ROS production; therefore, it is conceivable that transient depolarization could reduce ROS production. However, transient depolarization has been observed with increased ROS production. Therefore, the exact contribution of transient depolarization to ROS production has not been elucidated. In this study, we examined how the spontaneous transient depolarization occurring in individual mitochondria affected ROS production. When the matrix pH increased after the addition of malate or exposure of the isolated mitochondria to a high-pH buffer, transient depolarization was stimulated. Similar stimulation by an increased matrix pH was also observed in the mitochondria in intact H9c2 cells. Modifying the mitochondrial membrane potential and matrix pH by adding K+ in the presence of valinomycin, a K+ ionophore, clarified that an increase in the matrix pH is a major cause of ROS generation. When we added ADP in the presence of oligomycin to suppress the transient depolarization without decreasing the matrix pH, we observed the suppression of mitochondrial respiration, increased matrix pH, and enhanced ROS production. Based on these results, we propose a model where spontaneous transient depolarization occurs during increased proton influx through proton channels opened by increased matrix pH, leading to the suppression of ROS production. This study improves our understanding of mitochondrial behavior.

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Impact of CD14 on Reactive Oxygen Species Production from Human Leukocytes Primed byEscherichia coliLipopolysaccharides

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/6043245 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Dmitry S. Kabanov ◽

Olga Yu. Vwedenskaya ◽

Marina A. Fokina ◽

Elena M. Morozova ◽

Sergey V. Grachev ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Reactive Oxygen ◽

Polymorphonuclear Neutrophils ◽

Ros Generation ◽

Ros Production ◽

Oxygen Species ◽

Human Pmns ◽

Species Production ◽

The Impact ◽

Priming Activity

Lipopolysaccharides (LPS) from Gram-negative bacteria prime human polymorphonuclear neutrophils (PMNs) via multicomponent receptor cluster including CD14 and MD-2·TLR4 for the enhanced release of reactive oxygen species (ROS) were triggered by bacterial derived peptideN-formyl-methionyl-leucyl-phenylalanine (fMLP). In this study, we investigated the impact of CD14 on LPS-induced priming of human PMNs for fMLP-triggered ROS generation (respiratory or oxidative) burst. Monoclonal antibodies against human CD14 (mAbs) as well as isotype-matched IgG2a did not influence significantly fMLP-triggered ROS production from LPS-unprimed PMNs. Anti-CD14 mAbs (clone UCHM-1) attenuated LPS-induced priming of PMNs as it had been mirrored by fMLP-triggered decrease of ROS production. Similar priming activity of S-LPS or Re-LPS fromEscherichia colifor fMLP-triggered ROS release from PMNs was found. Obtained results suggest that glycosylphosphatidylinositol-anchored CD14 is the key player in LPS-induced PMN priming for fMLP-triggered ROS production. We believe that blockade of CD14 on the cell surface and clinical use of anti-CD14 mAbs or their Fab fragments may diminish the production of ROS and improve outcomes during cardiovascular diseases manifested by LPS-induced inflammation.

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Reactive Oxygen Species in Host Plant Are Required for an Early Defense Response against Attack of Stagonospora nodorum Berk. Necrotrophic Effectors SnTox

Plants ◽

10.3390/plants10081586 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1586

Author(s):

Svetlana Veselova ◽

Tatyana Nuzhnaya ◽

Guzel Burkhanova ◽

Sergey Rumyantsev ◽

Igor Maksimov

Keyword(s):

Reactive Oxygen Species ◽

Early Stage ◽

Reactive Oxygen ◽

Triticum Aestivum L ◽

Redox Status ◽

Stagonospora Nodorum ◽

Ros Generation ◽

Ros Production ◽

Oxygen Species ◽

Necrotrophic Effectors

Reactive oxygen species (ROS) play a central role in plant immune responses. The most important virulence factors of the Stagonospora nodorum Berk. are multiple fungal necrotrophic effectors (NEs) (SnTox) that affect the redox-status and cause necrosis and/or chlorosis in wheat lines possessing dominant susceptibility genes (Snn). However, the effect of NEs on ROS generation at the early stages of infection has not been studied. We studied the early stage of infection of various wheat genotypes with S nodorum isolates -Sn4VD, SnB, and Sn9MN, carrying a different set of NE genes. Our results indicate that all three NEs of SnToxA, SnTox1, SnTox3 significantly contributed to cause disease, and the virulence of the isolates depended on their differential expression in plants (Triticum aestivum L.). The Tsn1–SnToxA, Snn1–SnTox1and Snn3–SnTox3 interactions played an important role in inhibition ROS production at the initial stage of infection. The Snn3–SnTox3 inhibited ROS production in wheat by affecting NADPH-oxidases, peroxidases, superoxide dismutase and catalase. The Tsn1–SnToxA inhibited ROS production in wheat by affecting peroxidases and catalase. The Snn1–SnTox1 inhibited the production of ROS in wheat by mainly affecting a peroxidase. Collectively, these results show that the inverse gene-for gene interactions between effector of pathogen and product of host sensitivity gene suppress the host’s own PAMP-triggered immunity pathway, resulting in NE-triggered susceptibility (NETS). These results are fundamentally changing our understanding of the development of this economical important wheat disease.

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CYP450 Mediates Reactive Oxygen Species Production in a Mouse Model of β-Thalassemia through an Increase in 20-HETE Activity

International Journal of Molecular Sciences ◽

10.3390/ijms22031106 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1106

Author(s):

Rayan Bou-Fakhredin ◽

Batoul Dia ◽

Hilda E. Ghadieh ◽

Stefano Rivella ◽

Maria Domenica Cappellini ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Mouse Model ◽

Cell Injury ◽

Nicotinamide Adenine Dinucleotide Phosphate ◽

Reactive Oxygen ◽

Ros Generation ◽

Oxygen Species ◽

Species Production ◽

Different Sources ◽

Dependent Pathway

Oxidative damage by reactive oxygen species (ROS) is one of the main contributors to cell injury and tissue damage in thalassemia patients. Recent studies suggest that ROS generation in non-transfusion-dependent (NTDT) patients occurs as a result of iron overload. Among the different sources of ROS, the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family of enzymes and cytochrome P450 (CYP450) have been proposed to be major contributors for oxidative stress in several diseases. However, the sources of ROS in patients with NTDT remain poorly understood. In this study, Hbbth3/+ mice, a mouse model for β-thalassemia, were used. These mice exhibit an unchanged or decreased expression of the major NOX isoforms, NOX1, NOX2 and NOX4, when compared to their C57BL/6 control littermates. However, a significant increase in the protein synthesis of CYP4A and CYP4F was observed in the Hbbth3/+ mice when compared to the C57BL/6 control mice. These changes were paralleled by an increased production of 20-hydroxyeicosatetraenoic acid (20-HETE), a CYP4A and CYP4F metabolite. Furthermore, these changes corroborate with onset of ROS production concomitant with liver injury. To our knowledge, this is the first report indicating that CYP450 4A and 4F-induced 20-HETE production mediates reactive oxygen species overgeneration in Hbbth3/+ mice through an NADPH-dependent pathway.

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Intradialytic granulocyte reactive oxygen species production: a prospective, crossover trial.

Journal of the American Society of Nephrology ◽

10.1681/asn.v42178 ◽

1993 ◽

Vol 4 (2) ◽

pp. 178-186 ◽

Cited By ~ 2

Author(s):

J Himmelfarb ◽

K A Ault ◽

D Holbrook ◽

D A Leeber ◽

R M Hakim

Keyword(s):

Reactive Oxygen Species ◽

Reactive Oxygen ◽

Fold Increase ◽

Ros Production ◽

Oxygen Species ◽

Susceptibility To Infection ◽

Flow Cytometric ◽

Ros Formation ◽

Dialysis Membranes ◽

Species Production

By the use of flow cytometric techniques, this prospective, randomized crossover study was designed to analyze intradialytic granulocyte reactive oxygen species (ROS) formation in whole blood with complement-activating and noncomplement-activating hollow fiber membranes. Dialysis with a complement-activating membrane resulted in a 6.5-fold increase in granulocyte hydrogen peroxide production 15 min after dialysis initiation and remained significantly elevated (P < 0.01) through the first 30 min with this membrane in comparison to both predialysis values and simultaneous values with a noncomplement-activating membrane. Further studies demonstrated that blood obtained at 15 min with a complement-activating membrane generated significantly less granulocyte ROS production in response to Staphylococcus aureus incubation than blood obtained either predialysis or at the same time in dialysis with a noncomplement-activating membrane. Both complement-activating and noncomplement-activating dialysis membranes caused slightly decreased granulocyte responsiveness to phorbol myristate acetate. It was concluded that hemodialysis with complement-activating membranes results in increased granulocyte ROS production and decreased responsiveness to S. aureus challenge during the dialysis procedure. These results document the potential role of ROS in hemodialysis-associated pathology and susceptibility to infection.

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Abstract 19967: Differential Roles of the NADPH-Oxidase 1 and 2 in Platelet Activation and Thrombosis

Circulation ◽

10.1161/circ.132.suppl_3.19967 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Michael K Delaney ◽

Kyungho Kim ◽

Brian Estevez ◽

Aleksandra Stojanovic-Terpo ◽

Bo Shen ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Platelet Activation ◽

Nicotinamide Adenine Dinucleotide Phosphate ◽

Reactive Oxygen ◽

Ros Generation ◽

Ros Production ◽

Oxygen Species ◽

General Role ◽

Glycoprotein Vi ◽

Activation Pathways

Objective: Reactive oxygen species (ROS) generated from activated platelets is known to regulate platelet activation. However, it remains unclear whether and how different isoforms of nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) oxidases (NOXs) play roles in different platelet activation pathways. Here we investigated the role of NOX1 and NOX2 in different platelet activation pathways using NOX1 and NOX2 knockout mice. Approach and Results: NOX1-/- platelets showed selective defects in G protein coupled receptor (GPCR)-mediated platelet activation induced by thrombin, protease-activated receptor 4 agonist peptide (PAR4AP) and thromboxane A2 analog U46619, but was not affected in platelet activation induced by collagen-related peptide (CRP), a glycoprotein VI (GPVI) agonist. In contrast, NOX2-/- platelets showed potent inhibition of CRP-induced platelet activation, and also showed partial inhibition of thrombin-induced platelet aggregation and secretion. Consistently, production of reactive oxygen species (ROS) was inhibited in NOX1-/- platelets stimulated with thrombin, but not CRP, whereas NOX2-/- platelets showed reduced ROS generation induced by CRP or thrombin. Interestingly, laser-induced arterial thrombosis was impaired in NOX2-/- mice, and in thrombocytopenic mice transfused with NOX2-/- platelets, suggesting an important role for NOX2-dependent platelet ROS production in the laser-induced injury model of thrombosis. Conclusions: NOX1 and NOX2 play differential roles in different platelet activation pathways: NOX1 mediates GPCR-mediated ROS production and platelet activation, whereas NOX2 plays a general role in GPVI- and GPCR-induced ROS production and platelet activation in vitro , and in laser-induced thrombosis in vivo .

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2-Hydroxymelatonin, Rather Than Melatonin, Is Responsible for RBOH-Dependent Reactive Oxygen Species Production Leading to Premature Senescence in Plants

Antioxidants ◽

10.3390/antiox10111728 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1728

Author(s):

Hyoung Yool Lee ◽

Kyoungwhan Back

Keyword(s):

Reactive Oxygen Species ◽

Reactive Oxygen ◽

Ion Leakage ◽

Ros Production ◽

Oxygen Species ◽

Aba Signaling ◽

Melatonin Treatment ◽

Leaf Chlorosis ◽

Leaf Necrosis ◽

Species Production

Unlike animals, plants amply convert melatonin into 2-hydroxymelatonin (2-OHM) and cyclic 3-hydroxymelatonin (3-OHM) through the action of melatonin 2-hydroxylase (M2H) and melatonin 3-hydroxylase (M3H), respectively. Thus, the effects of exogenous melatonin treatment in plants may be caused by melatonin, 2-OHM, or 3-OHM, or some combination of these compounds. Indeed, studies of melatonin’s effects on reactive oxygen species (ROS) production have reported conflicting results. In this study, we demonstrated that 2-OHM treatment induced ROS production, whereas melatonin did not. ROS production from 2-OHM treatment occurred in old arabidopsis leaves in darkness, consistent with an ethylene-mediated senescence mechanism. Transgenic tobacco plants containing overexpressed rice M2H exhibited dwarfism and leaf necrosis of the upper leaves and early senescence of the lower leaves. We also demonstrated that 2-OHM-mediated ROS production is respiratory burst NADPH oxidase (RBOH)-dependent and that 2-OHM-induced senescence genes require ethylene and the abscisic acid (ABA) signaling pathway in arabidopsis. In contrast to melatonin, 2-OHM treatment induced senescence symptoms such as leaf chlorosis and increased ion leakage in arabidopsis. Senescence induction is known to begin with decreased levels of proteins involved in chloroplast maintenance, including Lhcb1 and ClpR1. Together, these results show that 2-OHM acts as a senescence-inducing factor by inducing ROS production in plants.

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Mitochondrial uncoupling does not decrease reactive oxygen species production after ischemia-reperfusion

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00189.2014 ◽

2014 ◽

Vol 307 (7) ◽

pp. H996-H1004 ◽

Cited By ~ 14

Author(s):

Ricardo Quarrie ◽

Daniel S. Lee ◽

Levy Reyes ◽

Warren Erdahl ◽

Douglas R. Pfeiffer ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Myocardial Dysfunction ◽

Ischemia Reperfusion ◽

Reactive Oxygen ◽

Ros Production ◽

Oxygen Species ◽

Sprague Dawley ◽

Mitochondrial Uncoupling ◽

Mitochondrial Ros ◽

Ros Formation

Cardiac ischemia-reperfusion (IR) leads to myocardial dysfunction by increasing production of reactive oxygen species (ROS). Mitochondrial H+ leak decreases ROS formation; it has been postulated that increasing H+ leak may be a mechanism of decreasing ROS production after IR. Ischemic preconditioning (IPC) decreases ROS formation after IR, but the mechanism is unknown. We hypothesize that pharmacologically increasing mitochondrial H+ leak would decrease ROS production after IR. We further hypothesize that IPC would be associated with an increase in the rate of H+ leak. Isolated male Sprague-Dawley rat hearts were subjected to either control or IPC. Mitochondria were isolated at end equilibration, end ischemia, and end reperfusion. Mitochondrial membrane potential (mΔΨ) was measured using a tetraphenylphosphonium electrode. Mitochondrial uncoupling was achieved by adding increasing concentrations of FCCP. Mitochondrial ROS production was measured by fluorometry using Amplex-Red. Pyridine dinucleotide levels were measured using HPLC. Before IR, increasing H+ leak decreased mitochondrial ROS production. After IR, ROS production was not affected by increasing H+ leak. H+ leak increased at end ischemia in control mitochondria. IPC mitochondria showed no change in the rate of H+ leak throughout IR. NADPH levels decreased after IR in both IPC and control mitochondria while NADH increased. Pharmacologically, increasing H+ leak is not a method of decreasing ROS production after IR. Replenishing the NADPH pool may be a means of scavenging the excess ROS thereby attenuating oxidative damage after IR.

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Reactive Oxygen Species Are Differentially Regulated in Chronic Myeloid Leukemia Versus Philadelphia Negative Myeloproliferative Neoplasms

Blood ◽

10.1182/blood.v112.11.4215.4215 ◽

2008 ◽

Vol 112 (11) ◽

pp. 4215-4215

Author(s):

Estelle Guerin ◽

Francis Belloc ◽

Gabriel Etienne ◽

Pierre Duffau ◽

Francois-Xavier Mahon ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Bone Marrow ◽

Peripheral Blood ◽

Myeloproliferative Neoplasms ◽

Reactive Oxygen ◽

Ros Generation ◽

Separate Analysis ◽

Ros Production ◽

Oxygen Species ◽

Normal Cells

Abstract Deregulation of tyrosine-kinases is a characteristic of most Myeloproliferative Neoplasms (MPN); evolution from chronic phase to acute leukemia depends on the acquisition of additional mutations. Reactive Oxygen Species (ROS), the production of which is increased by tyrosine-kinase activation, can be responsible for additional mutations. The role of ROS in generating genetic aberrations has been mainly studied in BCR-ABL-positive cell lines. Little is known of ROS metabolism in primary cells from CML or Philadelphia-negative MPN (Ph-MPN). After informed consent, cells from blood or bone marrow were obtained from patients diagnosed with CML (12 bone marrow (BM), 8 peripheral blood (PB)), or Ph-MPN (4 Polycythemia Vera, 6 Essential Thrombocythemia, 3 Primary Myelofibroses, 2 atypical CML) and from healthy donors (bone marrow donors) or patients devoid of hematological disease undergoing thoracotomy. Cells were incubated with DCFDA, a fluorogenic marker of ROS production, labelled with an anti-CD45 antibody, stimulated with either the oxidant hydrogen peroxide (H2O2) or the PKC activator Phorbol Myristate Acetate (PMA), and analysed for ROS production by flow cytometry. CD45/SSC gating allowed separate analysis of granulocytes, monocytes or lymphocytes. The basal level of ROS was not higher in CML cells as compared to normal BM or PB leukocytes. It was even significantly lower in CML lymphocytes, either from the BM (2.35 Arbitrary Units vs 8.3 AU, p=5.5 10−5) or PB (2.47 AU vs 7.4 AU, p=3.10−5) and in CML granulocytes from peripheral blood (14 AU vs 45 AU, p =10 −5), but not bone marrow. The ROS levels of Ph-MPN cells were similar or slightly higher than control cells. Upon H2O2 stimulation however, ROS production increased significantly more in CML cells as compared to normal cells (6 fold increase), whatever the cell type (granulocytes, monocytes and lymphocytes) or their origin (PB or BM). In contrast, for Ph-MPN cells, H2O2-stimulated ROS production was close to that of normal cells, with only BM lymphocytes showing ROS generation four fold higher than control BM lymphocytes. After PMA stimulation, which yielded a more modest ROS production than H2O2, CML cells behaved similarly to normal cells, whereas ROS production was four fold higher in Ph-MPN cells, whatever their type and origin. In conclusion, ROS levels at the basal stage are not higher in MPN cells, whether they are Philadelphia positive or negative, as compared to normal cells. Various kinds of stimulation induce different patterns of response, CML cells being more sensitive to oxidants whereas Ph-MPN cells respond more to the cytokine-mimicking agent PMA. These results suggest that the mechanisms of ROS generation and thus of genetic instability are different in CML and Ph-MPN.

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Reactive oxygen species production and discontinuous gas exchange in insects

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2011.1243 ◽

2011 ◽

Vol 279 (1730) ◽

pp. 893-901 ◽

Cited By ~ 14

Author(s):

Leigh Boardman ◽

John S. Terblanche ◽

Stefan K. Hetz ◽

Elrike Marais ◽

Steven L. Chown

Keyword(s):

Reactive Oxygen Species ◽

Gas Exchange ◽

Oxidative Damage ◽

Negative Relationship ◽

Reactive Oxygen ◽

Organizational Level ◽

Ros Production ◽

Oxygen Species ◽

Time Flow ◽

Species Production

While biochemical mechanisms are typically used by animals to reduce oxidative damage, insects are suspected to employ a higher organizational level, discontinuous gas exchange mechanism to do so. Using a combination of real-time, flow-through respirometry and live-cell fluorescence microscopy, we show that spiracular control associated with the discontinuous gas exchange cycle (DGC) in Samia cynthia pupae is related to reactive oxygen species (ROS). Hyperoxia fails to increase mean ROS production, although minima are elevated above normoxic levels. Furthermore, a negative relationship between mean and mean ROS production indicates that higher ROS production is generally associated with lower . Our results, therefore, suggest a possible signalling role for ROS in DGC, rather than supporting the idea that DGC acts to reduce oxidative damage by regulating ROS production.

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Effect of Single Layer Centrifugation on reactive oxygen species and sperm mitochondrial membrane potential in cooled stallion semen

Reproduction Fertility and Development ◽

10.1071/rd15440 ◽

2017 ◽

Vol 29 (5) ◽

pp. 1039 ◽

Cited By ~ 16

Author(s):

J. M. Morrell ◽

A. Lagerqvist ◽

P. Humblot ◽

A. Johannisson

Keyword(s):

Reactive Oxygen Species ◽

Hydrogen Peroxide ◽

Membrane Potential ◽

Mitochondrial Membrane Potential ◽

Mitochondrial Membrane ◽

Reactive Oxygen ◽

Single Layer ◽

Ros Production ◽

Oxygen Species ◽

Species Production

Additional means are needed for evaluating the quality of stallion spermatozoa in semen doses for AI. Mitochondrial membrane potential (ΔΨm) has been linked to fertility in some species, but is rarely used in the evaluation of cooled stallion semen; metabolic activity may be associated with reactive oxygen species production (ROS). In the present study, ΔΨm and ROS production were measured in doses of cooled stallion semen. The effect of colloid centrifugation on these parameters was also investigated. In this case, colloid centrifugation involves centrifuging a sperm sample through a silane-coated silica colloid formulation to retrieve the most robust spermatozoa. High and low ΔΨm in cooled stallion semen varied between stallions and between ejaculates, but was not affected by single-layer centrifugation (SLC). The SLC-selected spermatozoa produced significantly less hydrogen peroxide than controls (P < 0.001), which could explain the increased longevity and retention of fertilising capacity seen in previous studies. For SLC samples, ΔΨm was positively associated with viable spermatozoa that were not producing reactive oxygen species (r = 0.49; P < 0.001) and negatively associated with ROS production (for superoxide: r = –0.4, P < 0.01; for hydrogen peroxide: r = –0.39, P < 0.05). There was no clear association between ΔΨm and ROS production in control samples.

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