1
|
|
2
|
Fulceri F, Ferrucci M, Lenzi P, Soldani P, Bartalucci A, Paparelli A, Gesi M. MDMA (ecstasy) enhances loud noise-induced morphofunctional alterations in heart and adrenal gland. Microsc Res Tech 2011; 74:874-87. [PMID: 23939676 DOI: 10.1002/jemt.20971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 10/26/2010] [Indexed: 11/09/2022]
Abstract
Noise is an environmental stressor increasingly more present in modern life and, in particular, in a variety of recreational contexts. The aim of this work is to show the effects of noise on the myocardium and adrenal gland, through a careful review of the literature dealing with the peripheral effects of noise exposure in experimental and clinical studies. Noise induces adverse effects in human health, principally involving the cardiovascular and autonomic nervous systems, and the endocrine apparatus. Several factors in recreational environments potentially worsen the effects induced by loud noise. Among these, the intake of 3,4-methylenedioxymethamphetamine (MDMA) is frequently associated with noise exposure in recreational situations, because of its high compliance within social and relaxation settings. For this reason, MDMA is defined as a club drug--as its intake by young people often occurs in association with other factors, such as aggregation, high temperatures, and noise. It is known that self-administration of MDMA by humans causes severe toxicity. In particular, the myocardium is affected early after MDMA intake--resulting in tachycardia, hypertension, and arrhythmia. Furthermore, MDMA alters the activity of the adrenal glands by elevating catecholamines and corticosterone levels. This review shows that combining MDMA and loud noise exposure potentiates the effects that are produced by each single stimulant alone as seen in experimental animal models. The convergence of the effects of prolonged loud noise exposure and the consumption of MDMA on the same system might explain the sudden fatal events that happen in recreational situations.
Collapse
Affiliation(s)
- Federica Fulceri
- Department of Human Morphology and Applied Biology, University of Pisa, Pisa, Italy
| | | | | | | | | | | | | |
Collapse
|
3
|
Heyno E, Mary V, Schopfer P, Krieger-Liszkay A. Oxygen activation at the plasma membrane: relation between superoxide and hydroxyl radical production by isolated membranes. PLANTA 2011; 234:35-45. [PMID: 21359959 DOI: 10.1007/s00425-011-1379-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 02/06/2011] [Indexed: 05/25/2023]
Abstract
Production of reactive oxygen species (hydroxyl radicals, superoxide radicals and hydrogen peroxide) was studied using EPR spin-trapping techniques and specific dyes in isolated plasma membranes from the growing and the non-growing zones of hypocotyls and roots of etiolated soybean seedlings as well as coleoptiles and roots of etiolated maize seedlings. NAD(P)H mediated the production of superoxide in all plasma membrane samples. Hydroxyl radicals were only produced by the membranes of the hypocotyl growing zone when a Fenton catalyst (FeEDTA) was present. By contrast, in membranes from other parts of the seedlings a low rate of spontaneous hydroxyl radical formation was observed due to the presence of small amounts of tightly bound peroxidase. It is concluded that apoplastic hydroxyl radical generation depends fully, or for the most part, on peroxidase localized in the cell wall. In soybean plasma membranes from the growing zone of the hypocotyl pharmacological tests showed that the superoxide production could potentially be attributed to the action of at least two enzymes, an NADPH oxidase and, in the presence of menadione, a quinone reductase.
Collapse
Affiliation(s)
- Eiri Heyno
- Commissariat à l'Energie Atomique (CEA Saclay), iBiTec-S, CNRS URA 2096, Service de Bioénergétique Biologie Structurale et Mécanisme, Bât. 532, 91191 Gif-sur-Yvette, France
| | | | | | | |
Collapse
|
4
|
Schopfer P, Heyno E, Drepper F, Krieger-Liszkay A. Naphthoquinone-dependent generation of superoxide radicals by quinone reductase isolated from the plasma membrane of soybean. PLANT PHYSIOLOGY 2008; 147:864-78. [PMID: 18408044 PMCID: PMC2409040 DOI: 10.1104/pp.108.118745] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Accepted: 04/08/2008] [Indexed: 05/04/2023]
Abstract
Using a tetrazolium-based assay, a NAD(P)H oxidoreductase was purified from plasma membranes prepared from soybean (Glycine max) hypocotyls. The enzyme, a tetramer of 85 kD, produces O2(.-) by a reaction that depended on menadione or several other 1,4-naphthoquinones, in apparent agreement with a classification as a one-electron-transferring flavoenzyme producing semiquinone radicals. However, the enzyme displayed catalytic and molecular properties of obligatory two-electron-transferring quinone reductases of the DT-diaphorase type, including insensitivity to inhibition by diphenyleneiodonium. This apparent discrepancy was clarified by investigating the pH-dependent reactivity of menadionehydroquinone toward O2 and identifying the protein by mass spectrometry and immunological techniques. The enzyme turned out to be a classical NAD(P)H:quinone-acceptor oxidoreductase (EC 1.6.5.2, formerly 1.6.99.2) that reduces menadione to menadionehydroquinone and subsequently undergoes autoxidation at pH > or = 6.5. Autoxidation involves the production of the semiquinone as an intermediate, creating the conditions for one-electron reduction of O2. The possible function of this enzyme in the generation of O2(.-) and H2O2 at the plasma membrane of plants in vivo is discussed.
Collapse
Affiliation(s)
- Peter Schopfer
- Universität Freiburg, Institut für Biologie II, D-79104 Freiburg, Germany
| | | | | | | |
Collapse
|
5
|
Lambeth JD, Krause KH, Clark RA. NOX enzymes as novel targets for drug development. Semin Immunopathol 2008; 30:339-63. [PMID: 18509646 DOI: 10.1007/s00281-008-0123-6] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 04/25/2008] [Indexed: 02/07/2023]
Abstract
The members of the NOX/DUOX family of NADPH oxidases mediate such physiologic functions as host defense, cell signaling, and thyroid hormone biosynthesis through the generation of reactive oxygen species (ROS), including superoxide anion and hydrogen peroxide. Moreover, ROS are involved in a broad range of fundamental biochemical and cellular processes, and data accumulated in recent years indicate that the NOX enzymes comprise one of the most important biological sources of ROS. Given the high biochemical reactivity of ROS, it is not surprising that they have been implicated in a wide variety of pathologies and diseases. Prominent among the settings that feature ROS-mediated tissue injury are disorders associated with inflammation, aging, and progressive degenerative changes in cells and organ systems, and it appears that essentially no organ system is exempt. Among the disorders currently believed to be mediated at least in part by NOX-derived ROS are hypertension, aortic aneurysm, myocardial infarction (and other ischemia-reperfusion disorders), pulmonary fibrosis and hypertension, amyotropic lateral sclerosis, Alzheimer's disease, Parkinson's disease, ischemic stroke, diabetic nephropathy, and renal cell carcinoma. Several small-molecule and peptide inhibitors of the NOX enzymes have been useful in experimental studies, but issues of specificity, potency, and toxicity militate against any of the existing published compounds as candidates for drug development. Given the broad array of disease targets documented in recent work, the time is here for vigorous efforts to develop clinically useful inhibitors of the NOX enzymes. As most (though not all) NOX-related diseases appear to be mediated by a single member of the NOX family, agents with isoform specificity will be preferred, although broadly active NOX inhibitors may prove to be useful in some settings.
Collapse
|
6
|
Nossaman BD, Kadowitz PJ. Potential Benefits of Peroxynitrite. THE OPEN PHARMACOLOGY JOURNAL 2008; 2:31-53. [PMID: 19305646 PMCID: PMC2659344 DOI: 10.2174/1874143600802010031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 03/24/2008] [Accepted: 04/29/2008] [Indexed: 12/14/2022]
Abstract
Peroxynitrite (PN) is generated by the reaction of nitric oxide (NO) and superoxide in one of the most rapid reactions in biology. Studies have reported that PN is a cytotoxic molecule that contributes to vascular injury in a number of disease states. However, it has become apparent that PN has beneficial effects including vasodilation, inhibition of platelet aggregation, inhibition of inflammatory cell adhesion, and protection against ischemia/reperfusion injury in the heart. It is our hypothesis that PN may serve to inactivate superoxide and prolong the actions of NO in the circulation. This manuscript reviews the beneficial effects of PN in the cardiovascular system.
Collapse
Affiliation(s)
- Bobby D. Nossaman
- Critical Care Medicine, Department of Anesthesiology, Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, Louisiana 70121 USA
- Department of Pharmacology, Tulane University Medical Center, 1430 Tulane Avenue, New Orleans, Louisiana 70112-2699 USA
| | - Philip J. Kadowitz
- Department of Pharmacology, Tulane University Medical Center, 1430 Tulane Avenue, New Orleans, Louisiana 70112-2699 USA
| |
Collapse
|
7
|
Szymczyk KH, Kerr BAE, Freeman TA, Adams CS, Steinbeck MJ. Involvement of hydrogen peroxide in the differentiation and apoptosis of preosteoclastic cells exposed to arsenite. Biochem Pharmacol 2006; 72:761-9. [PMID: 16876763 DOI: 10.1016/j.bcp.2006.06.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 06/08/2006] [Accepted: 06/08/2006] [Indexed: 11/21/2022]
Abstract
Long-term exposure to sodium arsenite (AsO(2)) promotes the development of various cancers. Paradoxically, arsenic also induces pro-myelomonocytic leukemia cell differentiation, and at higher concentrations, apoptosis. The present study investigated the effects of AsO(2) on preosteoclasts. When treated with 2.5-5microM AsO(2), RAW264.7 cells underwent osteoclast differentiation as evidenced by an increase in the number of multinucleate cells expressing tartrate resistant acid phosphatase (TRAP). The appearance of these phenotypic markers was preceded by a low level increase in extracellular production of H(2)O(2) and was prevented by the addition of catalase (4.5microg/ml), an enzyme that removes H(2)O(2). Only at high concentrations (10-25microM) of AsO(2) was a significant loss of cell viability and a high level increase in H(2)O(2) production (1.5microM) observed. Apoptosis was blocked by pretreatment with diphenylene iodonium chloride (2microM), a NAD(P)H-flavoprotein inhibitor, suggesting the involvement of NADPH-oxidase. The data show that AsO(2), dose-dependently, stimulates increasing amounts of H(2)O(2) production. Moreover, at concentrations found in tissues of individuals exposed to geochemical AsO(2), osteoclasts underwent an H(2)O(2)-dependent differentiation. Therefore, chronic exposure to low-level amounts of AsO(2) could result in increased bone resorption and contribute to bone related pathologies.
Collapse
Affiliation(s)
- K H Szymczyk
- Department of Orthopaedic Surgery, Thomas Jefferson University, 1015 Walnut Street, Suite 501 Curtis, Philadelphia, PA, USA.
| | | | | | | | | |
Collapse
|
8
|
Staali L, Bauer S, Mörgelin M, Björck L, Tapper H. Streptococcus pyogenes bacteria modulate membrane traffic in human neutrophils and selectively inhibit azurophilic granule fusion with phagosomes. Cell Microbiol 2006; 8:690-703. [PMID: 16548894 DOI: 10.1111/j.1462-5822.2005.00662.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We recently reported that the human pathogen Streptococcus pyogenes of the M1 serotype survives and replicates intracellularly after being phagocytosed by human neutrophils. These data raised the possibility that the generation of reactive oxygen metabolites by neutrophils, and the release of microbicidal molecules from their azurophilic and specific granules into phagosomes, can be modulated by S. pyogenes bacteria expressing surface-associated M and/or M-like proteins. We now demonstrate, using flow cytometry, immunofluorescence microscopy and transmission electron microscopy, that live wild-type S. pyogenes, after internalization by human neutrophils, inhibits the fusion of azurophilic granules with phagosomes. In contrast, azurophilic granule-content is efficiently delivered to phagosomes containing bacteria not expressing M and/or M-like proteins. Also, when heat-killed wild-type bacteria are used as the phagocytic prey, fusion of azurophilic granules with phagosomes is observed. The inhibition caused by live wild-type S. pyogenes is specific for azurophilic granule-phagosome fusion, because the mobilization of specific granules and the production of reactive oxygen species are induced to a similar extent by all strains tested. In conclusion, our results demonstrate that viable S. pyogenes bacteria expressing M and M-like proteins selectively prevent the fusion of azurophilic granules with phagosomes.
Collapse
Affiliation(s)
- Leïla Staali
- Department of Clinical Sciences, Section for Clinical and Experimental Infectious Medicine, BMC, B14, Lund University, Tornavägen 10, SE-221 84 Lund, Sweden
| | | | | | | | | |
Collapse
|
9
|
He YY, Huang JL, Block ML, Hong JS, Chignell CF. Role of Phagocyte Oxidase in UVA-Induced Oxidative Stress and Apoptosis in Keratinocytes. J Invest Dermatol 2005; 125:560-6. [PMID: 16117799 DOI: 10.1111/j.0022-202x.2005.23851.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Chronic exposure to ultraviolet radiation including ultraviolet A (315-400 nm) (UVA) may cause photocarcinogenesis and photoaging. The UVA-induced production of reactive oxygen species (ROS) and the resultant oxidative stress exposure play an important role in these biological processes. Here we have investigated the role of phagocyte oxidase (PHOX, gp91phox) in the production of ROS, redox status change, and apoptosis after UVA exposure by using gp91phox-deficient (gp91phox-/-) primary keratinocytes. UVA radiation resulted in increased ROS production and oxidation of reduced glutathione (GSH) to its oxidized form (GSSG). The presence of diphenylene iodonium (DPI) inhibited ROS production by UVA. In comparison with wild-type cells, gp91phox-/- cells produced slightly less ROS and GSH oxidation. UVA radiation induced apoptosis in wild-type keratinocytes as detected by phosphatidylserine (PS) translocation, caspase activation, and DNA fragmentation. As compared with wild-type cells, UVA induced less PS translocation in gp91phox-deficient cells. No difference, however, was observed in caspase activation and DNA fragmentation after UVA exposure in wild-type and gp91phox-/- cells. These findings suggest that gp91phox plays a limited role in the UVA-induced ROS production, oxidative stress, and therefore the PS translocation, but has no effect on UVA-induced caspase activation and DNA fragmentation during apoptosis.
Collapse
Affiliation(s)
- Yu-Ying He
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
| | | | | | | | | |
Collapse
|
10
|
Affiliation(s)
- Gregor Rothe
- Bremer Zentrum für Laboratoriumsmedizin GmbH, D-28205 Bremen, Germany
| | | |
Collapse
|
11
|
Riganti C, Gazzano E, Polimeni M, Costamagna C, Bosia A, Ghigo D. Diphenyleneiodonium inhibits the cell redox metabolism and induces oxidative stress. J Biol Chem 2004; 279:47726-31. [PMID: 15358777 DOI: 10.1074/jbc.m406314200] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Diphenyleneiodonium (DPI) and the structurally related compound diphenyliodonium (DIP) are widely used as inhibitors of flavoenzymes, particularly NADPH oxidase. Here we report further evidence that DPI and DIP are not specific flavin binders. A 3-h incubation of N11 glial cells with DPI significantly inhibited in a dose-dependent way both the pentose phosphate pathway and the tricarboxylic acid cycle. In parallel, we observed a dose-dependent increase of reactive oxygen species generation and lipoperoxidation and increased leakage of lactate dehydrogenase activity in the extracellular medium. The glutathione/glutathione disulfide ratio decreased, whereas the efflux of glutathione out of the cells increased. This suggests that DPI causes an augmented oxidative stress and exerts a cytotoxic effect in N11 cells. Indeed, the cells were protected from these events when loaded with glutathione. Similar results were observed using DIP instead of DPI and also in other cell types. We suggest that the DPI-elicited inhibition of the pentose phosphate pathway and tricarboxylic acid cycle may be mediated by the blockade of several NAD(P)-dependent enzymes, such as glucose 6-phosphate dehydrogenase, glyceraldehyde 3-phosphate dehydrogenase, and lactate dehydrogenase. In light of these results, we think that some effects of DPI or DIP in in vitro and in vivo experimental models should be interpreted with caution.
Collapse
Affiliation(s)
- Chiara Riganti
- Department of Genetics, Biology, and Biochemistry, University of Torino, Via Santena 5/bis, 10126 Torino, Italy
| | | | | | | | | | | |
Collapse
|
12
|
Audi SH, Zhao H, Bongard RD, Hogg N, Kettenhofen NJ, Kalyanaraman B, Dawson CA, Merker MP. Pulmonary arterial endothelial cells affect the redox status of coenzyme Q0. Free Radic Biol Med 2003; 34:892-907. [PMID: 12654478 DOI: 10.1016/s0891-5849(03)00025-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The pulmonary endothelium is capable of reducing certain redox-active compounds as they pass from the systemic venous to the arterial circulation. This may have important consequences with regard to the pulmonary and systemic disposition and biochemistry of these compounds. Because quinones comprise an important class of redox-active compounds with a range of physiological, toxicological, and pharmacological activities, the objective of the present study was to determine the fate of a model quinone, coenzyme Q0 (Q), added to the extracellular medium surrounding pulmonary arterial endothelial cells in culture, with particular attention to the effect of the cells on the redox status of Q in the medium. Spectrophotometry, electron paramagnetic resonance (EPR), and high-performance liquid chromatography (HPLC) demonstrated that, when the oxidized form Q is added to the medium surrounding the cells, it is rapidly converted to its quinol form (QH2) with a small concentration of semiquinone (Q*-) also detectable. The isolation of cell plasma membrane proteins revealed an NADH-Q oxidoreductase located on the outer plasma membrane surface, which apparently participates in the reduction process. In addition, once formed the QH2 undergoes a cyanide-sensitive oxidation by the cells. Thus, the actual rate of Q reduction by the cells is greater than the net QH2 output from the cells.
Collapse
Affiliation(s)
- Said H Audi
- Department of Biomedical Engineering, Marquette University, Milwaukee, WI, USA
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Wright MV, Kuhn TB. CNS neurons express two distinct plasma membrane electron transport systems implicated in neuronal viability. J Neurochem 2002; 83:655-64. [PMID: 12390527 DOI: 10.1046/j.1471-4159.2002.01176.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Trans-plasma membrane electron transport is critical for maintaining cellular redox balance and viability, yet few, if any, investigations have studied it in intact primary neurons. In this investigation, extracellular reduction of 2,6-dichloroindophenol (DCIP) and ferricyanide (FeCN) were measured as indicators of trans-plasma membrane electron transport by chick forebrain neurons. Neurons readily reduced DCIP, but not FeCN unless CoQ(1), an exogenous ubiquinone analog, was added to the assays. CoQ(1) stimulated FeCN reduction in a dose-dependent manner but had no effect on DCIP reduction. Reduction of both substrates was totally inhibited by epsilon-maleimidocaproic acid (MCA), a membrane-impermeant thiol reagent, and slightly inhibited by superoxide dismutase. Diphenylene iodonium, a flavoenzyme inhibitor, completely inhibited FeCN reduction but had no affect on DCIP reduction, suggesting that these substrates are reduced by distinct redox pathways. The relationship between plasma membrane electron transport and neuronal viability was tested using the inhibitors MCA and capsaicin. MCA caused a dose-dependent decline in neuronal viability that closely paralleled its inhibition of both reductase activities. Similarly capsaicin, a NADH oxidase inhibitor, induced a rapid decline in neuronal viability. These results suggest that trans-plasma membrane electron transport helps maintain a stable redox environment required for neuronal viability.
Collapse
Affiliation(s)
- M V Wright
- Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska, USA
| | | |
Collapse
|
14
|
Dri P, Presani G, Perticarari S, Albèri L, Prodan M, Decleva E. Measurement of phagosomal pH of normal and CGD-like human neutrophils by dual fluorescence flow cytometry. CYTOMETRY 2002; 48:159-66. [PMID: 12116362 DOI: 10.1002/cyto.10123] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Phagosomal pH is thought to play an important role in the antimicrobial activity of polymorphonuclear leukocytes (PMNs). In this study, we set up a method for a rapid and accurate measurement of phagosomal pH in PMNs with the use of Candida albicans doubly labeled with a pH-insensitive and a pH-sensitive probe and flow cytometry. METHODS Heat-killed, serum-opsonized C. albicans were doubly labeled with fluorescein, a pH-sensitive probe, and rhodamine, a pH-insensitive probe, and incubated with human PMNs. Flow cytometric readings of PMN-associated Candida were then taken, and the intraphagosomal pH was calculated on the basis of the ratio of fluorescein:rhodamine fluorescence by using a calibration curve obtained after equilibration of phagosomal pH with different external pH values after addition of digitonin. RESULTS A rapid rise in phagosomal pH, which reached pH 7.8, was observed 2 min after initiation of phagocytosis and progressively declined to pH 6.9 after 15 min. Such a rise was not observed in PMNs with defective microbicidal activity (deficient in nicotinamide adenine dinucleotide phosphate oxidase), where phagosomal pH dropped to pH 6.6, 2 min after phagocytosis. The abnormal initial acidification in PMNs deficient in nicotinamide adenine dinucleotide phosphate oxidase was prevented by using lysosomotropic weak bases or the vacuolar-type H(+) pump inhibitor concanamycin A. CONCLUSIONS Phagosomal pH of PMNs can be easily and accurately measured by dual fluorescence flow cytometry. The method can be applied to assess phagosomal pH in PMNs with defective microbicidal activity and to monitor the outcome of pharmacologic interventions aimed at correcting its abnormalities.
Collapse
Affiliation(s)
- Pietro Dri
- Department of Physiology and Pathology, University of Trieste, Trieste, Italy.
| | | | | | | | | | | |
Collapse
|
15
|
Audi SH, Bongard RD, Okamoto Y, Merker MP, Roerig DL, Dawson CA. Pulmonary reduction of an intravascular redox polymer. Am J Physiol Lung Cell Mol Physiol 2001; 280:L1290-9. [PMID: 11350810 DOI: 10.1152/ajplung.2001.280.6.l1290] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pulmonary endothelial cells in culture reduce external electron acceptors via transplasma membrane electron transport (TPMET). In studying endothelial TPMET in intact lungs, it is difficult to exclude intracellular reduction and reducing agents released by the lung. Therefore, we evaluated the role of endothelial TPMET in the reduction of a cell-impermeant redox polymer, toluidine blue O polyacrylamide (TBOP(+)), in intact rat lungs. When added to the perfusate recirculating through the lungs, the venous effluent TBOP(+) concentration decreased to an equilibrium level reflecting TBOP(+) reduction and autooxidation of its reduced (TBOPH) form. Adding superoxide dismutase (SOD) to the perfusate increased the equilibrium TBOP(+) concentration. Kinetic analysis indicated that the SOD effect could be attributed to elimination of the superoxide product of TBOPH autooxidation rather than of superoxide released by the lungs, and experiments with lung-conditioned perfusate excluded release of other TBOP(+) reductants in sufficient quantities to cause significant TBOP(+) reduction. Thus the results indicate that TBOP(+) reduction is via TPMET and support the utility of TBOP(+) and the kinetic model for investigating TPMET mechanisms and their adaptations to physiological and pathophysiological stresses in the intact lung.
Collapse
Affiliation(s)
- S H Audi
- Department of Biomedical Engineering, Marquette University, Milwaukee, WI 53201-1881, USA
| | | | | | | | | | | |
Collapse
|
16
|
Components and organization of the nadph oxidase of phagocytic cells. PHAGOCYTOSIS: THE HOST 1999. [DOI: 10.1016/s1874-5172(99)80043-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
17
|
Hoshino M, Baba T. Laser Photolysis of Iron(III) Tetraphenylporphyrin in Methanol. A Kinetic Study on the Formation of the Superoxide Anion Radical from the Dioxygen Adduct of Iron(II) Tetraphenylporphyrin. J Am Chem Soc 1998. [DOI: 10.1021/ja9806783] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mikio Hoshino
- The Institute of Physical and Chemical Research Wako, Saitama 351, Japan
| | - Tomoya Baba
- The Institute of Physical and Chemical Research Wako, Saitama 351, Japan
| |
Collapse
|
18
|
Hiran TS, Moulton PJ, Hancock JT. Detection of superoxide and NADPH oxidase in porcine articular chondrocytes. Free Radic Biol Med 1997; 23:736-43. [PMID: 9296450 DOI: 10.1016/s0891-5849(97)00054-3] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Porcine articular chondrocytes have the capacity to release superoxide in response to the addition of the calcium ionophore ionomycin in a concentration-dependent manner. This activity was not stimulated by the addition of fMetLeuPhe or the kinase activator phorbol myristate acetate (PMA). However, this release of superoxide was inhibited by iodonium diphenyl (IDP), suggesting the involvement of NADPH oxidase. Reverse transcriptase polymerase chain reaction (RT-PCR) using oligonucleotides designed against the known sequences for the human phagocyte NADPH oxidase showed the expression of p22-phox, p40-phox, and p47-phox mRNA, while Western blot analysis of chondrocyte extracts using polyclonal antisera raised against the human phagocyte NADPH oxidase suggested the presence of the p67-phox polypeptide. These results suggest that porcine articular chondrocytes can release reactive oxygen species using a NADPH oxidase-like complex.
Collapse
Affiliation(s)
- T S Hiran
- Faculty of Applied Sciences, University of the West of England, Bristol, UK
| | | | | |
Collapse
|
19
|
Affiliation(s)
- Peter J. Stang
- Department of Chemistry, University of Minnesota-Duluth, Duluth, Minnesota 55812
| | | |
Collapse
|
20
|
Affiliation(s)
- L M Henderson
- Department of Biochemistry, School of Medical Sciences, University of Bristol, UK
| | | |
Collapse
|
21
|
Bishop A, Paz MA, Gallop PM, Karnovsky ML. Inhibition of redox cycling of methoxatin (PQQ), and of superoxide release by phagocytic white cells. Free Radic Biol Med 1995; 18:617-20. [PMID: 9101256 DOI: 10.1016/0891-5849(94)00178-m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The iodonium compounds diphenyleneiodonium and diphenyliodonium, and the amine compounds, 4,5-dimethyl phenylene diamine, N,N-dimethyl 1,4-phenylene diamine, 1,2-diamino-4,5-methyleneoxybenzene, and aminomalononitrile inhibit methoxatin's (PQQ's) redox activity in vitro, that is, the methoxatin-coupled oxidation of glycine and reduction of nitroblue tetrazolium to formazan. The compounds mentioned above also inhibit phorbol myristate acetate (PMA) stimulated superoxide release by phagocytic white cells--determined mainly as the superoxide dismutase sensitive reduction of ferricytochrome C. Related compounds, 3,4-diaminopyridine and 4-dimethylamino-benzylamine, did not inhibit redox activity of PQQ in vitro, nor did they inhibit PMA stimulated superoxide production in monocytes or neutrophils. Thus, there is a correlation between an agent's ability to inhibit PQQ redox cycling and its ability to inhibit superoxide release by phagocytes. The findings are a further indication that PQQ is involved in the respiratory burst of phagocytic cells.
Collapse
Affiliation(s)
- A Bishop
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | |
Collapse
|
22
|
Goldwasser E, Alibali P, Gardner A. Differential inhibition by iodonium compounds of induced erythropoietin expression. J Biol Chem 1995; 270:2628-9. [PMID: 7852328 DOI: 10.1074/jbc.270.6.2628] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Diphenylene iodonium chloride suppresses the cobaltous chloride-induced expression of erythropoietin by Hep3B cells to about 50% at a concentration of 30 nM. At that concentration, it has no effect on the response to low oxygen. The related compound iodonium diphenyl chloride acts similarly but is a much less effective inhibitor. If, as reported, diphenylene iodonium chloride is a specific inhibitor of cytochrome b, it follows that the response to CoCl2 is dependent on that enzyme but the response to hypoxia is not.
Collapse
Affiliation(s)
- E Goldwasser
- Department of Biochemistry and Molecular Biology, University of Chicago, Illinois 60637
| | | | | |
Collapse
|
23
|
Münzel T, Sayegh H, Freeman BA, Tarpey MM, Harrison DG. Evidence for enhanced vascular superoxide anion production in nitrate tolerance. A novel mechanism underlying tolerance and cross-tolerance. J Clin Invest 1995; 95:187-94. [PMID: 7814613 PMCID: PMC295403 DOI: 10.1172/jci117637] [Citation(s) in RCA: 541] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We sought to examine mechanisms underlying nitroglycerin (NTG) tolerance and "cross-tolerance" to other nitrovasodilators. Rabbits were treated for 3 d with NTG patches (0.4 mg/h) and their aortic segments studied in organ chambers. Relaxations were examined after preconstriction with phenylephrine. In NTG tolerant rabbit aorta, relaxations to cGMP-dependent vasodilators such as NTG (45 +/- 6%), SIN-1 (69 +/- 7%), and acetylcholine (ACh, 64 +/- 5%) were attenuated vs. controls, (90 +/- 2, 94 +/- 3, and 89 +/- 2% respectively, P < 0.05 for all), while responses to the cAMP-dependent vasodilator forskolin remained unchanged. In tolerant aorta, endothelial removal markedly enhanced relaxations to NTG and SIN-1 (82 +/- 4 and 95 +/- 3%, respectively). Other studies were performed to determine how the endothelium enhances tolerance. Vascular steady state .-O2 levels (assessed by lucigenin chemiluminescence) was increased twofold in tolerant vs. control vessels with endothelium (0.31 +/- 0.01 vs. 0.61 +/- 0.01 nmol/mg per minute). This difference was less in vessels after denudation of the endothelium. Diphenylene iodonium, an inhibitor of flavoprotein containing oxidases, and Tiron a direct .-O2 scavenger normalized .-O2 levels. In contrast, oxypurinol (1 mM) an inhibitor of xanthine oxidase, rotenone (50 microM) an inhibitor of mitochondrial electron transport and NG-nitro-L-arginine (100 microM) an inhibitor of nitric oxide synthase did not affect the chemiluminescence signals from NTG-tolerant aortas. Pretreatment of tolerant aorta with liposome-entrapped, pH sensitive superoxide dismutase (600 U/ml) significantly enhanced maximal relaxation in response to NTG, SIN-1, and ACh, and effectively reduced chemiluminescence signals. These studies show that continuous NTG treatment is associated with increased vascular .-O2-production and consequent inhibition of NO. mediated vasorelaxation produced by both exogenous and endogenous nitrovasodilators.
Collapse
Affiliation(s)
- T Münzel
- Department of Medicine, Emory University School of Medicine, Atlanta Veterans Administration Medical Center, Georgia 30322
| | | | | | | | | |
Collapse
|
24
|
Thrasher AJ, Keep NH, Wientjes F, Segal AW. Chronic granulomatous disease. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1227:1-24. [PMID: 7918677 DOI: 10.1016/0925-4439(94)90100-7] [Citation(s) in RCA: 168] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- A J Thrasher
- Division of Molecular Medicine, University College London, Medical School, UK
| | | | | | | |
Collapse
|
25
|
Abstract
PQQ, also called methoxatin, has been isolated from guinea-pig neutrophils. The organic cations diphenyleneiodonium (DPI) and diphenyliodonium (BPI) and the aromatic o-diamine 4,5-dimethylphenylenediamine (DIMPDA) sequester synthetic PQQ and inhibit its redox-cycling activity in a model system. Standards were made of adducts of tritiated PQQ with unlabeled DIMPDA and of unlabeled PQQ with tritiated DPI or DIMPDA. PQQ adducts were isolated from guinea-pig neutrophils with each of the tritiated inhibitors. They were separated and defined by high-performance liquid chromatography (HPLC). Tiron, a disodium benzene disulphonic acid, broke the DPI-PQQ adduct isolated from neutrophils and released free PQQ. Both DPI and DIMPDA, as well as BPI, blocked O2.- release by stimulated neutrophils. The blockade exerted by these inhibitors was released by the addition of PQQ to the cell suspensions. The data demonstrate the presence of PQQ in guinea-pig neutrophils and suggest that it has a possible role, direct or indirect, in the O2.(-)-producing respiratory burst.
Collapse
Affiliation(s)
- A Bishop
- Department of Genetics, Harvard Medical School, Harvard School of Dental Medicine, Boston, MA
| | | | | | | |
Collapse
|
26
|
Cross A, Yarchover J, Curnutte J. The superoxide-generating system of human neutrophils possesses a novel diaphorase activity. Evidence for distinct regulation of electron flow within NADPH oxidase by p67-phox and p47-phox. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31824-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
27
|
Dème D, Doussiere J, De Sandro V, Dupuy C, Pommier J, Virion A. The Ca2+/NADPH-dependent H2O2 generator in thyroid plasma membrane: inhibition by diphenyleneiodonium. Biochem J 1994; 301 ( Pt 1):75-81. [PMID: 8037694 PMCID: PMC1137145 DOI: 10.1042/bj3010075] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The thyroid plasma membrane contains a Ca(2+)-regulated NADPH-dependent H2O2-generating system which provides H2O2 for the peroxidase-catalysed biosynthesis of thyroid hormones. The electron transfer from NADPH to O2 catalysed by this system was studied by using diphenyleneiodonium (DPI), an inhibitor of flavo- and haemo-proteins. The prosthetic group of the H2O2 generator was removed by incubation with 5 mM CHAPS at 40 degrees C, and an active holoenzyme was reconstituted with FAD, but not with FMN. The H2O2-generating system also had an intrinsic Ca(2+)-dependent NADPH:ferricyanide reductase activity which is probably linked to its flavodehydrogenase component (or domain). Both activities, H2O2 production and ferricyanide reductase activity, were inhibited by DPI, with similar K1/2 (2.5 nmol/mg of protein). DPI only inhibited a system reduced with NADPH in the presence of Ca2+. NADPH could not be replaced by NADP+, NADH or sodium dithionite, suggesting the need for specific mild reduction of a redox centre in a particular conformation. Ferricyanide protected both activities against inhibition by DPI; the NADPH:ferricyanide reductase activity was completely protected at a ferricyanide concentration 20 times lower than that needed to protect the H2O2 formation, implying at least two target sites for DPI. One might be the flavodehydrogenase component; the other was beyond, on the entity which transfers the electrons to O2. This second site has not been identified.
Collapse
Affiliation(s)
- D Dème
- INSERM U. 96, Le Kremlin-Bicêtre, France
| | | | | | | | | | | |
Collapse
|
28
|
Affiliation(s)
- G Rothe
- Institute for Clinical Chemistry and Laboratory Medicine, University of Regensburg, Germany
| | | |
Collapse
|
29
|
O'Donnell BV, Tew DG, Jones OT, England PJ. Studies on the inhibitory mechanism of iodonium compounds with special reference to neutrophil NADPH oxidase. Biochem J 1993; 290 ( Pt 1):41-9. [PMID: 8439298 PMCID: PMC1132380 DOI: 10.1042/bj2900041] [Citation(s) in RCA: 447] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Diphenyleneiodonium (DPI) and its analogues have been previously shown to react via a radical mechanism whereby an electron is abstracted from a nucleophile to form a radical, which then adds back to the nucleophile to form covalent adducts [Banks (1966) Chem. Rev. 66, 243-266]. We propose that the inhibition of neutrophil NADPH oxidase by DPI occurs via a similar mechanism. A reduced redox centre in the oxidase could serve as electron donor to DPI, and inhibition would occur after direct phenylation of the redox cofactor, or of adjacent amino acid groups by the DPI radical. In the absence of an activatory stimulus, human neutrophil NADPH-oxidase was not inhibited by DPI. The Ki for time-dependent inhibition by DPI of human neutrophil membrane NADPH oxidase was found to be 5.6 microM. Inhibitory potency of DPI was shown to be directly related to rate of enzyme turnover, indicating the need for a reduced redox centre. Adducts were formed between photoreduced flavin (FAD or FMN) and inhibitor (DPI or diphenyliodonium). These were separated by h.p.l.c. and characterized by absorbance spectroscopy, 1H-n.m.r. and fast-atom-bombardment m.s. and found to have properties consistent with substituted 4a,5-dihydroflavins. After incubation of pig neutrophil membranes with DPI, the quantity of recoverable intact flavin was greatly diminished when NADPH was present to initiate oxidase turnover, indicating that the flavin may be the site of DPI activation. These results may provide a common mechanism of action for iodonium compounds as inhibitors of other flavoenzymes.
Collapse
Affiliation(s)
- B V O'Donnell
- Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K
| | | | | | | |
Collapse
|
30
|
Glaser CB, Morser J, Clarke JH, Blasko E, McLean K, Kuhn I, Chang RJ, Lin JH, Vilander L, Andrews WH, Light DR. Oxidation of a specific methionine in thrombomodulin by activated neutrophil products blocks cofactor activity. A potential rapid mechanism for modulation of coagulation. J Clin Invest 1992; 90:2565-73. [PMID: 1334978 PMCID: PMC443416 DOI: 10.1172/jci116151] [Citation(s) in RCA: 183] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Endothelial thrombomodulin (TM) plays a critical role in hemostasis as a cofactor for thrombin-dependent formation of activated protein C, a potent anticoagulant. Chloramine T, H2O2, or hypochlorous acid generated from H2O2 by myeloperoxidase rapidly destroy 75-90% of TM cofactor activity. Activated PMN, the primary in vivo source of biological oxidants, also rapidly inactivate TM. Oxidation of TM by PMN is inhibited by diphenylene iodonium, an inhibitor of NADPH oxidase. Both Met291 and Met388 in the six epidermal growth factor-like repeat domain are oxidized; however, only substitutions of Met388 lead to TM analogues that resist oxidative inactivation. We suggest that in inflamed tissues activated PMN may inactivate TM and demonstrate further evidence of the interaction between the inflammatory process and induction of thrombotic potential.
Collapse
Affiliation(s)
- C B Glaser
- Department of Protein Chemistry, Berlex Biosciences, South San Francisco, California 94080
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Doussière J, Vignais PV. Diphenylene iodonium as an inhibitor of the NADPH oxidase complex of bovine neutrophils. Factors controlling the inhibitory potency of diphenylene iodonium in a cell-free system of oxidase activation. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 208:61-71. [PMID: 1324836 DOI: 10.1111/j.1432-1033.1992.tb17159.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Diphenylene iodonium (Ph2I), a lipophilic reagent, is an efficient inhibitor of the production of O2- by the activated NADPH oxidase of bovine neutrophils. In a cell-free system of NADPH oxidase activation consisting of neutrophil membranes and cytosol from resting cells, supplemented with guanosine 5'-[gamma-thio]triphosphate, MgCl2 and arachidonic acid, or in membranes isolated from neutrophils activated by 4 beta-phorbol 12-myristate 13-acetate, addition of a reducing agent, e.g. NADPH or sodium dithionite, markedly enhanced inhibition of the NADPH oxidase by Ph2I. The membrane fraction was found to contain the Ph2I-sensitive component(s). In the presence of a concentration of Ph2I sufficient to fully inhibit O2- production (around 10 nmol/mg membrane protein), addition of catalytic amounts of the redox mediator dichloroindophenol (Cl2Ind) resulted in a by-pass of the electron flow to cytochrome c, the rate of which was about half of that determined in non-inhibited oxidase. A marked increase in the efficiency of this by-pass was achieved by addition of sodium deoxycholate. The Cl2-Ind-mediated cytochrome c reduction was negligible in membranes isolated from resting neutrophils. At a higher concentration of Ph2I (100 nmol/mg membrane protein), the Cl2Ind-mediated cytochrome c reductase activity was only half inhibited, which indicated that, in the NADPH oxidase complex, there are at least two Ph2I sensitive components, differing by their sensitivity to the inhibitor. At low concentrations of Ph2I (less than 10 nmol/mg protein), the spectrum of reduced cytochrome b558 in isolated neutrophil membranes was modified, suggesting that the component sensitive to low concentrations of Ph2I is the heme binding component of cytochrome b558. Higher concentrations of Ph2I were found to inhibit the isolated NADPH dehydrogenase component of the oxidase complex. A number of membrane and cytosolic proteins were labeled by [125I]Ph2I. However, the radiolabeling of a membrane-bound 24-kDa protein, which might be the small subunit of cytochrome b558, responded more specifically to the conditions of activation and reduction which are required for inhibition of O2- production by Ph2I. The O2(-)-generating form of xanthine oxidase was also inhibited by Ph2I. Inhibition of xanthine oxidase, a non-heme iron flavoprotein, by Ph2I had a number of features in common with that of the neutrophil NADPH oxidase, namely the requirement of reducing conditions for inhibition of O2- production by Ph2I and the induction of a by-pass of electron flow to cytochrome c by Cl2Ind in the inhibited enzyme, suggesting some similarity in the molecular organization of the two enzymes.
Collapse
Affiliation(s)
- J Doussière
- Département de Biologie Moléculaire et Structurale, Centre d'Etudes Nucléaires, Grenoble, France
| | | |
Collapse
|
32
|
Segal AW, West I, Wientjes F, Nugent JH, Chavan AJ, Haley B, Garcia RC, Rosen H, Scrace G. Cytochrome b-245 is a flavocytochrome containing FAD and the NADPH-binding site of the microbicidal oxidase of phagocytes. Biochem J 1992; 284 ( Pt 3):781-8. [PMID: 1320378 PMCID: PMC1132607 DOI: 10.1042/bj2840781] [Citation(s) in RCA: 287] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The NADPH oxidase of phagocytic cells is important for the efficient killing and digestion of ingested microbes. A very unusual low-potential cytochrome b (b-245) is the only redox molecule to have been identified in this system. The FAD-containing flavoprotein that binds NADPH and transfers electrons to the cytochrome has eluded identification for three decades. We show here that the haem/FAD ratio in the membranes does not change significantly on activation of this oxidase, indicating that the FAD is present in the membranes from the outset and not recruited from the cytosol. The FAD content of membranes from cells of patients with X-linked chronic granulomatous disease (CGD) lacking the cytochrome b was roughly one-quarter of that in normal subjects and in autosomal recessive CGD patients lacking the cytosolic protein p47-phox. Similar low amounts of FAD were present in uninduced promyelocytic (HL60) cells, suggesting that the low amount of FAD in cells from X-CGD patients was probably unrelated to this oxidase system. Cytochrome b-245 appears to bind both the haem and FAD, in a molar ratio of 2:1. The e.p.r. signal of the purified cytochrome was weak and had an asymmetric g(z) peak at g = 3.31. The purified cytochrome could be partially reflavinated (about 20%) in the presence of lipid. Amino acid sequence homology was detected between the beta-subunit of this cytochrome b and the ferredoxin-NADP+ reductase (FNR) family of reductases in the putative NADPH- and FAD-binding sites. 32P-labelled 2-azido-NADP was used as a photoaffinity label for the NADPH-binding site. Labelling that was competed off with NADP was observed in the region of the beta-subunit of the cytochrome. No labelling was seen in this region in X-CGD in three subjects in whom this cytochrome was missing and in a third in whom it was present but bore a Pro-His transposition in the putative NADPH-binding site. These studies indicate that cytochrome b-245 is a flavocytochrome, the first described in higher eukaryotic cells, bearing the complete electron-transporting apparatus of the NADPH oxidase.
Collapse
Affiliation(s)
- A W Segal
- Department of Medicine, University College London, Rayne Institute, U.K
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Kapus A, Szászi K, Ligeti E. Phorbol 12-myristate 13-acetate activates an electrogenic H(+)-conducting pathway in the membrane of neutrophils. Biochem J 1992; 281 ( Pt 3):697-701. [PMID: 1371386 PMCID: PMC1130747 DOI: 10.1042/bj2810697] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The mode of activation of an H(+)-conducting pathway present in the membrane of neutrophils was investigated. (1) Resting neutrophils released protons through an electrogenic Cd(2+)-inhibitable (K0.5 approximately 20 microM) route when a pH gradient and appropriate charge compensation was provided. (2) The rate of H+ efflux was stimulated over 2.5-fold by 4 beta-phorbol 12-myristate 13-acetate (PMA; K0.5 approximately 0.7 nM) or by 4 beta-phorbol 12,13-dibutyrate (K0.5 approximately 20 nM) even when the NADPH oxidase was blocked by p-chloromercuribenzoate. (3) Staurosporine inhibited the effect of PMA. (4) The H+ egress was not enhanced by 4 alpha-phorbol 12,13-didecanoate. (5) Low concentrations of Cd2+ (less than 40 microM) inhibited the H+ flux without influencing the oxidase. The results raise the possibility that protein kinase C could be involved in the activation of an electrogenic H(+)-conducting pathway in the membrane of neutrophils. The activation of this route by phorbol esters seems to be independent of the stimulation of NADPH oxidase.
Collapse
Affiliation(s)
- A Kapus
- Department of Physiology, Semmelweis University Medical School, Budapest, Hungary
| | | | | |
Collapse
|
34
|
Radeke H, Cross A, Hancock J, Jones O, Nakamura M, Kaever V, Resch K. Functional expression of NADPH oxidase components (alpha- and beta-subunits of cytochrome b558 and 45-kDa flavoprotein) by intrinsic human glomerular mesangial cells. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54815-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
35
|
Cross AR, Jones OT. Enzymic mechanisms of superoxide production. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1057:281-98. [PMID: 1851438 DOI: 10.1016/s0005-2728(05)80140-9] [Citation(s) in RCA: 361] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A R Cross
- Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K
| | | |
Collapse
|
36
|
Meier B, Cross AR, Hancock JT, Kaup FJ, Jones OT. Identification of a superoxide-generating NADPH oxidase system in human fibroblasts. Biochem J 1991; 275 ( Pt 1):241-5. [PMID: 1850240 PMCID: PMC1150038 DOI: 10.1042/bj2750241] [Citation(s) in RCA: 179] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Human fibroblasts have the capacity to release superoxide radicals upon stimulation of an electron transport system similar to the NADPH oxidase of leukocytes. Two components of the NADPH oxidase system, (1) a flavoprotein of 45 kDa which binds diphenylene iodonium (a compound described as a specific inhibitor of the leukocyte NADPH oxidase), and (2) a low-potential cytochrome b, are present in fibroblast membranes. Fibroblasts exhibit these compounds at lower concentrations than do polymorphonuclear leukocytes or B-lymphocytes. The superoxide-generating system is rather uniformly associated with the outer cell membrane, as shown by light and electron microscopy. Superoxide release upon stimulation with various agents was prevented by the addition of micromolar concentrations of diphenylene iodonium, making an NADPH oxidase a likely source.
Collapse
Affiliation(s)
- B Meier
- Chemisches Institut, Tierärztliche Hochschule, Hannover, Federal Republic of Germany
| | | | | | | | | |
Collapse
|
37
|
Doussiere J, Vignais PV. Inhibition of O2-. generating oxidase of neutrophils by iodonium biphenyl in a cell free system: effect of the redox state of the oxidase complex. Biochem Biophys Res Commun 1991; 175:143-51. [PMID: 1847802 DOI: 10.1016/s0006-291x(05)81212-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The conditions of inhibition of neutrophil O2-. generating oxidase by iodonium biphenyl (IBP) were studied. In a cell free system of oxidase activation consisting of neutrophil membranes and cytosol, GTP-gamma-S, Mg2+ and arachidonic acid, the inhibitory effect of IBP depended on the redox conditions of the medium. Inhibition was observed when the medium was supplemented with dithionite or NADPH. When the cell free system was incubated with IBP in the absence of reducing agents, full oxidase activity was recovered after removal of free IBP by gel filtration. Bovine neutrophil membranes, but not cytosol, contained component(s) sensitive to IBP. Upon treatment of neutrophil membranes by IBP followed by reduction, the spectrum of reduced cytochrome b558 was modified, suggesting that cytochrome b558 is a target site for IBP.
Collapse
Affiliation(s)
- J Doussiere
- Département de Biologie Moléculaire et Structurale, Centre d'Etudes Nucléaires, Grenoble, France
| | | |
Collapse
|
38
|
Hancock JT, White JI, Jones OT, Silver IA. The use of diphenylene iodonium and its analogues to investigate the role of the NADPH oxidase in the tumoricidal activity of macrophages in vitro. Free Radic Biol Med 1991; 11:25-9. [PMID: 1937127 DOI: 10.1016/0891-5849(91)90184-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Lipopolysaccharide (LPS) was shown to induce tumoricidal activity in peritoneal macrophages. The optimal concentration was found to be 25 micrograms/mL. Approximately 20-h exposure to LPS was required before maximal tumor cell killing was attained. Optimal tumor killing was obtained with a ratio of tumor cell to macrophages of 1:40 with the macrophages in a confluent layer. Diphenylene iodonium (DPI) reduced the tumor cell killing in a dose dependent manner up to 1 microM. Under similar conditions DPI was shown to inhibit the superoxide production of macrophages and this supports the view that the production of oxygen radicals is important in the killing of tumor cells by macrophages and that the inhibitor DPI can be used to investigate their contribution to cytotoxicity.
Collapse
Affiliation(s)
- J T Hancock
- Department of Biochemistry, School of Medical Sciences, University of Bristol, UK
| | | | | | | |
Collapse
|
39
|
Affiliation(s)
- O T Jones
- Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K
| | | | | |
Collapse
|
40
|
Laporte F, Doussiere J, Vignais PV. Respiratory burst of rabbit peritoneal neutrophils. Transition from an NADPH diaphorase activity to an .O2(-)-generating oxidase activity. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 194:301-8. [PMID: 2174779 DOI: 10.1111/j.1432-1033.1990.tb19457.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Superoxide (.O2-) production by the NADPH oxidase of a membrane fraction derived from rabbit peritoneal neutrophils activated by 4 beta-phorbol 12-myristate 13-acetate (PMA) was studied at 25 degrees C under different conditions, and measured by the superoxide dismutase inhibitable reduction of cytochrome c. Whereas PMA-activated rabbit neutrophils incubated in a glucose-supplemented medium exhibited a substantial rate of production of .O2-, the membranes prepared by sonication of the activated neutrophils were virtually unable to generate .O2- in the presence of NADPH. Instead, they exhibited an NADPH-dependent diaphorase activity, measured by the superoxide-dismutase-insensitive reduction of cytochrome c. Upon addition of arachidonic acid, which is known to elicit oxidase activation, the NADPH diaphorase activity of the rabbit neutrophil membranes vanished and was stoichiometrically replaced by an NADPH oxidase activity. The emerging oxidase activity was fully sensitive to iodonium biphenyl, a potent inhibitor of the respiratory burst, whereas the diaphorase activity was not affected. Addition of 0.1% Triton X-100 or an excess of arachidonic acid, acting as detergent, resulted in the reappearance of the diaphorase activity at the expense of the oxidase activity. These results indicate that the diaphorase-oxidase transition is reversible. When the rabbit neutrophil membranes were supplemented with rabbit neutrophil cytosol, guanosine 5'-[gamma-thio]triphosphate and Mg2+, in addition to arachidonic acid, not only the NADPH diaphorase activity disappeared, but the emerging NADPH oxidase activity was markedly enhanced (about 10 times compared to that of membranes treated with arachidonic acid alone). The diaphorase-oxidase transition was accompanied by a 10-fold increase in the Km for NADPH, suggesting a change of conformation propagated to the NADPH-binding site during the transition. The treatment of PMA-activated rabbit neutrophils with cross-linking reagents, like glutaraldehyde or 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide, prevented the loss of the PMA-elicited oxidase activity upon disruption of the cells by sonication, suggesting that the interactions between the components of the oxidase complex are stabilized by cross-linking.
Collapse
Affiliation(s)
- F Laporte
- Département de Biologie Moléculaire et Structurale, Centre d'Etudes Nucléaires, Grenoble, France
| | | | | |
Collapse
|
41
|
Yea CM, Cross AR, Jones OT. Purification and some properties of the 45 kDa diphenylene iodonium-binding flavoprotein of neutrophil NADPH oxidase. Biochem J 1990; 265:95-100. [PMID: 2154184 PMCID: PMC1136618 DOI: 10.1042/bj2650095] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The 45 kDa diphenylene iodonium-binding flavoprotein of the human neutrophil superoxide-generating oxidase has been purified by affinity chromatography. The polypeptide was eluted from Blue Memsep or 2',5'-ADP-agarose columns with either NADP or low concentrations of the specific inhibitor diphenylene iodonium. The purified protein was shown to bind FAD at a ratio of 1.09 mol of FAD/mol of protein. The reconstituted flavoprotein had a fluorescence spectrum similar, but not identical, to that of free FAD. It had an isoelectric point of approx. 4.0. The reconstituted flavoprotein displayed no diaphorase activity towards a range of artificial electron acceptors. Polyclonal antibodies raised against the pure protein inhibited superoxide generation by solubilized oxidase in a dose-dependent manner, and inhibited superoxide generation when incubated with either cytosol or membrane fractions in a reconstituted system. These antibodies precipitated the 45 kDa polypeptide together with a haem-containing 23 kDa protein thought to be the small subunit of cytochrome b-245. Antibodies raised against cytochrome P-450 reductase also precipitated these two polypeptides. These results are consistent with the 45 kDa polypeptide being the flavoprotein of the neutrophil superoxide-generating oxidase.
Collapse
Affiliation(s)
- C M Yea
- Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K
| | | | | |
Collapse
|
42
|
Ellis JA, Cross AR, Jones OT. Studies on the electron-transfer mechanism of the human neutrophil NADPH oxidase. Biochem J 1989; 262:575-9. [PMID: 2553003 PMCID: PMC1133307 DOI: 10.1042/bj2620575] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A superoxide-generating NADPH oxidase was solubilized from phorbol 12-myristate 13-acetate-activated human neutrophils with a mixture of sodium deoxycholate (0.125%, w/v) and Lubrol-PX (0.125%, v/v). The solubilized preparation contained FAD (577 pmol/mg of protein) and cytochrome b-245 (479 pmol/mg of protein) and produced 11.61 mol of O2-./s per mol of cytochrome b (340 nmol of O2-./min per mg of protein). On addition of NADPH, the cytochrome b-245 was reduced by 7.9% and the FAD by 38% in the aerobic steady state; NADH addition caused little steady-state reduction of cytochrome b and FAD. In this preparation, and several others, the measured rate of O2-. production correlated with the turnover of cytochrome b calculated from the extent of cytochrome b-245 reduction under aerobic conditions. Addition of diphenyleneiodonium abolished the reduction of both the FAD and cytochrome b-245 components and inhibited O2-. production. The haem ligand imidazole inhibited O2-. generation and cytochrome b reduction while permitting FAD reduction. These results support the suggestion that the human neutrophil NADPH oxidase has the electron-transport sequence: NADPH----FAD----cytochrome b-245----O2.
Collapse
Affiliation(s)
- J A Ellis
- Department of Biochemistry, Medical School, University of Bristol, U.K
| | | | | |
Collapse
|
43
|
Cotgreave IA, Duddy SK, Kass GE, Thompson D, Moldéus P. Studies on the anti-inflammatory activity of ebselen. Ebselen interferes with granulocyte oxidative burst by dual inhibition of NADPH oxidase and protein kinase C? Biochem Pharmacol 1989; 38:649-56. [PMID: 2537084 DOI: 10.1016/0006-2952(89)90211-6] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ebselen (PZ51, 2-phenyl-1,2-benzoisoselenazol-3-(2H)-one) was shown to be an inhibitor of human granulocyte oxidative burst stimulated by phorbol myristate acetate (IC50 25 microM). Estimation of the primary oxygen metabolites of the burst was complicated by the redox chemistry of Ebselen. Ebselen inhibited NADPH-stimulated superoxide generation by a partially purified NADPH oxidase preparation with an IC50 of 0.5-1.0 microM. Ebselen was also shown to inhibit the activity of partially purified Ca2+- and phospholipid-dependent protein kinase C (IC50 ca. 0.5 microM). Phorbol ester-stimulated phosphorylation of protein in intact cells was inhibited by Ebselen (IC50 ca. 50 microM). These pharmacodynamic properties of Ebselen are discussed in terms of its anti-inflammatory activity in vivo. The findings are also discussed in terms of Ebselen's known ability to interact with sulfhydryl components of cells, particularly critical thiol components of the enzymes studied.
Collapse
Affiliation(s)
- I A Cotgreave
- Department of Toxicology, Karolinska Institutet, Stockholm, Sweden
| | | | | | | | | |
Collapse
|
44
|
Parkinson JF, Gabig TG. Isolation of the respiratory burst oxidase: the role of a flavoprotein component. J Bioenerg Biomembr 1988; 20:653-77. [PMID: 2854127 DOI: 10.1007/bf00762547] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The article reviews the enzymatic and electron transfer properties of a low-potential FAD-dependent flavoprotein that is a component of the NADPH-dependent O2-.-generating respiratory burst oxidase of phagocytes. Current methods available for isolation of the respiratory burst oxidase and the flavoprotein component of the complex are also reviewed. These studies and data obtained from affinity-labeling of respiratory burst oxidase components, suggest that the flavoprotein has a molecular weight of 65-67 kD. The prevailing evidence suggests that the flavoprotein functions as a dehydrogenase/electron transferase and can directly catalyse NADPH-dependent O2-.formation when isolated. However, in neutrophil plasma membranes, the prevailing evidence suggests that the flavoprotein functions primarily to transfer electrons from NADPH to cytochrome b-245 and that this latter redox component is the catalytic side of O2-.formation. A working model for the arrangement of the flavoprotein and cytochrome b-245 components of the respiratory burst oxidase in neutrophil membranes is proposed.
Collapse
Affiliation(s)
- J F Parkinson
- Department of Medicine, Indiana University School of Medicine, Indianapolis 46223
| | | |
Collapse
|
45
|
Ellis JA, Mayer SJ, Jones OT. The effect of the NADPH oxidase inhibitor diphenyleneiodonium on aerobic and anaerobic microbicidal activities of human neutrophils. Biochem J 1988; 251:887-91. [PMID: 2843166 PMCID: PMC1149085 DOI: 10.1042/bj2510887] [Citation(s) in RCA: 142] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
NADPH-dependent superoxide production by intact human neutrophils is inhibited by DPI (diphenyleneiodonium), when stimulated by either FMLP (N-formylmethionyl-leucyl-phenylalanine) or PMA (phorbol 12-myristate 13-acetate). Addition of 10 microM-DPI abolished the reduction of both the FAD and the cytochrome b components of the NADPH oxidase. DPI inhibition of the oxidase was associated with defective aerobic killing of staphylococci by human neutrophils. Anaerobic killing, phagocytosis, chemotaxis and motility were relatively unaffected by 10 microM-DPI. Degranulation of the azurophil and specific granules, induced by the soluble stimuli FMLP or PMA, and by particulate stimuli was decreased by the presence of DPI. The above effects of DPI on human neutrophils are similar to those found in chronic granulomatous disease.
Collapse
Affiliation(s)
- J A Ellis
- Department of Biochemistry, Medical School, University of Bristol, U.K
| | | | | |
Collapse
|