NADPH:O<sub>2</sub> oxidoreductase of human eosinophils in the cell‐free system

Bolscher, Ben G.J.M.; Koenderman, Leo; Tool, Anton T.J.; Stokman, Petra M.; Roos, Dirk

doi:10.1016/0014-5793(90)81025-j

Cited by 22 publications

(13 citation statements)

References 22 publications

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“…This procedure measures only extracellular production of O 2 -, since O 2 -and cytochrome c are membrane impermeable. Previous studies using immunoblot analysis have demonstrated that eosinophils produce more NADPH oxidase than neutrophils, which was thought to explain why eosinophils generate more O 2 -than neutrophils (15,17,18). However, the discrepancy in O 2 -production between eosinophils and neutrophils may also be attributable to neutrophils preferentially generating O 2…”

Section: Discussionmentioning

confidence: 99%

“…The molecular mechanisms associated with NADPH oxidase assembly and activation have been studied in more detail in neutrophils (5, 8, 10 -13) and cell-free assays (10,14) than in eosinophils (15)(16)(17)(18)(19). This complex is composed of five essential subunits, the membrane-bound cytochrome b 558 (a complex of two subunits, p22 phox and gp91 phox ) which associates with cytosolic subunits Rac, p47…”

Section: Divergence Of Mechanisms Regulating Respiratory Burst In Blomentioning

confidence: 99%

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Divergence of Mechanisms Regulating Respiratory Burst in Blood and Sputum Eosinophils and Neutrophils from Atopic Subjects

Lacy

Latif

Steward

et al. 2003

The Journal of Immunology

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Eosinophil respiratory burst is an important event in asthma and related inflammatory disorders. However, little is known concerning activation of the respiratory burst NADPH oxidase in human eosinophils. Conversely, neutrophils are known to assemble NADPH oxidase in intracellular and plasma membranes. We hypothesized that eosinophils and neutrophils translocate NADPH oxidase to distinct intracellular locations, consistent with their respective functions in O2−-mediated cytotoxicity. PMA-induced O2– release assayed by cytochrome c was 3.4-fold higher in atopic human eosinophils than in neutrophils, although membrane-permeable dihydrorhodamine-123 showed similar amounts of release. Eosinophil O2– release was dependent on Rac, in that it was 54% inhibited by Clostridium difficile toxin B (400–800 ng/ml). In eosinophils stimulated with PMA, a pronounced shift of cytosolic Rac to p22phox-positive plasma membrane was observed by confocal microscopy, whereas neutrophils directed Rac2 mainly to intracellular sites coexpressing p22phox. Similarly, ex vivo sputum eosinophils from asthmatic subjects exhibited predominantly plasma membrane-associated immunoreactivity for Rac, whereas sputum neutrophils exhibited cytoplasmic Rac2 staining. Thus, activated sputum eosinophils, rather than neutrophils, may contribute significantly to the pathogenesis of asthma by extracellular release of tissue-damaging O2–. Our findings suggest that the differential modes of NADPH oxidase assembly in these cells may have important implications for oxidant-mediated tissue injury.

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Section: Discussionmentioning

confidence: 99%

Section: Divergence Of Mechanisms Regulating Respiratory Burst In Blomentioning

confidence: 99%

Divergence of Mechanisms Regulating Respiratory Burst in Blood and Sputum Eosinophils and Neutrophils from Atopic Subjects

Lacy

Latif

Steward

et al. 2003

The Journal of Immunology

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“…NADPH oxidase has been thoroughly studied in phagocytic cells (Babior, 2004;Batot et al, 1995;Cross and Segal, 2004); however, the presence of analogous NADPH oxidases in nonphagocytic cells also has been described (Bokoch and Knaus, 2003;Bolscher et al, 1990;Brozna et al, 1988;Lambeth, 2004). NADPH oxidase-like enzymes have been identified in vascular smooth muscle cells (Fukui et al, 1995), fibroblasts (Thannickal and Fanburg, 1995), endothelial cells (Jones et al, 1996), rat peripheral neurons (Dvorakova et al, 1999;Tammariello et al, 2000), cerebral cortical neurons (Noh and Koh, 2000), hippocampal pyramidal neurons, and cerebellar Purkinje neurons (Mizuki et al, 1998;Serrano et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Synaptic localization of a functional NADPH oxidase in the mouse hippocampus

Tejada‐Simon

Serrano

Villasana

et al. 2005

Molecular and Cellular Neuroscience

196

154

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Superoxide has been shown to be critical for hippocampal long-term potentiation (LTP) and hippocampus-dependent memory function. A possible source for the generation of superoxide during these processes is NADPH oxidase. The active oxidase consists of two membrane proteins, gp91 phox and p22 phox , and four cytosolic proteins, p40 phox , p47 phox , p67 phox , and Rac. Upon stimulation, the cytosolic proteins translocate to the membrane to form a complex with the membrane components, which results in production of superoxide. Here, we determined the presence, localization, and functionality of a NADPH oxidase in mouse hippocampus by examining the NADPH oxidase proteins as well as the production of superoxide. All of the NADPH oxidase proteins were present in hippocampal homogenates and enriched in synaptoneurosome preparations. Immunocytochemical analysis of cultured hippocampal neurons indicated that all NADPH oxidase proteins were localized in neuronal cell bodies as well as dendrites. Furthermore, double labeling analysis using antibodies to p67 phox and the presynaptic marker synaptophysin suggest a close association of the NADPH oxidase subunits with synaptic sites. Finally, stimulation of hippocampal slices with phorbol esters triggered translocation of the cytoplasmic NADPH oxidase proteins to the membrane and an increase in superoxide production that was blocked by inhibitors of NADPH oxidase. Taken together, our data suggest that NADPH oxidase is present in mouse hippocampus and might be the source of superoxide production required for LTP and memory function.

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“…Compared with neutrophils, there is a poor understanding of the events that transduce receptor activation to the release of these mediators from eosinophils. Furthermore, there is scant information concerning the contribution of plasma membrane electrical conductances to the regulation of the function of eosinophils, although the study of such events has proved to be difficult even in the more numerous neutrophil.In common with neutrophils, monocytes and macrophages, eosinophils possess a respiratory burst oxidase complex (NADPH: 02 oxidoreductase; Segal, Garcia, Goldstone, Cross & Jones, 1981;Bolscher, Koenderman, Tool, Stokman & Roos, 1990) which, upon cell activation, is fully assembled to undertake the single-electron reduction of oxygen to produce superoxide anion (Cross & Jones, 1991). The superoxide anion provides a basis for the subsequent production of other cytotoxic reactive oxidants including hydrogen peroxide, -OH and hypohalous acids.…”

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confidence: 99%

Voltage‐activated proton current in eosinophils from human blood.

Gordienko

Tare

Parveen

et al. 1996

The Journal of Physiology

114

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1. The resting membrane potential of freshly purified normodense human eosinophils bathed in and dialysed with quasi-physiological solutions was -63 + 2 mV (n = 100). 2. In voltage-clamp mode with quasi-physiological internal and external solutions, voltage steps from the holding potential of -60 mV to levels positive to +20 mV resulted in development of a quasi-instantaneous outward current and a slowly developing outward current. The instantaneous current was absent when the cells were bathed in and dialysed with K+-free solution.3. The slow outward current persisted following simultaneous replacement of K+, Na+ and most of the Cl-with largely impermeant ions (tetraethylammonium, N-methyl-D-glucamine and methanesulphonate) and was augmented when the cell was dialysed with a solution of increased buffering capacity for protons. The observed reversal potential of the current closely followed the hydrogen equilibrium potential over a wide range of internal-external pH combinations, indicating that the conductance underlying the slow outward current was highly selective for H+ ions. 4. Acidification of the pipette solution (increasing [H+]1) augmented the outward H+ current and shifted its activation range negatively, whilst acidification of the external solution had the opposite effect. The voltage dependence of the current is modulated by the transmembrane pH gradient so that only outward current could be activated. However, when the outward current was activated by a voltage step, rapid acidification of external solution produced an inward H+ current which rapidly deactivated. 5. The proton current was reversibly inhibited in a voltage-dependent manner by extracellular application of Zn2+. The apparent dissociation constants were 8 nm (at +40 mV), 36 nm (at +70 mV) and 200 nm (at +100 mV).6. The proton current was augmented by exposure to 10 ,UM arachidonic acid. This augmentation consisted of a shift of the voltage dependence of activation to more negative potentials and enhancement of maximum conductance (H,max Assessment of the role of the eosinophil in health and disease eosinophils are now incriminated as important effector cells has proved difficult because these cells constitute only a in a number of diverse human diseases. These include the small percentage of the total leucocyte population. This host response to parasite infestation and tumours, the contrasts with the relatively sophisticated understanding reaction to transplanted tissues, and both allergic and nonthat exists for the more abundant neutrophil. Nevertheless, allergic inflammatory reactions of the major organ systems (reviewed by Spry, 1988).* To whom correspondence should be addressed. Receptor-directed stimulation of eosinophils and neutrophils leads to the release of a wide repertoire of chemical mediators. Some of these exist preformed within secretory granules, whilst others, such as eicosanoids and oxidants, are generated de novo when the cell is stimulated. Compared with neutrophils, there is a poor understanding of the events that...

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NADPH:O₂ oxidoreductase of human eosinophils in the cell‐free system

Cited by 22 publications

References 22 publications

Divergence of Mechanisms Regulating Respiratory Burst in Blood and Sputum Eosinophils and Neutrophils from Atopic Subjects

Divergence of Mechanisms Regulating Respiratory Burst in Blood and Sputum Eosinophils and Neutrophils from Atopic Subjects

Synaptic localization of a functional NADPH oxidase in the mouse hippocampus

Voltage‐activated proton current in eosinophils from human blood.

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NADPH:O2 oxidoreductase of human eosinophils in the cell‐free system

Cited by 22 publications

References 22 publications

Divergence of Mechanisms Regulating Respiratory Burst in Blood and Sputum Eosinophils and Neutrophils from Atopic Subjects

Divergence of Mechanisms Regulating Respiratory Burst in Blood and Sputum Eosinophils and Neutrophils from Atopic Subjects

Synaptic localization of a functional NADPH oxidase in the mouse hippocampus

Voltage‐activated proton current in eosinophils from human blood.

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Product

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NADPH:O₂ oxidoreductase of human eosinophils in the cell‐free system