Regulation of Phagolysosome pH in Bovine and Human Neutrophils: The Role of NADPH Oxidase Activity and an Na+ /H+ Antiporter

1989 ◽  
Vol 45 (3) ◽  
pp. 239-248 ◽  
Author(s):  
Susan J. Mayer ◽  
Peter M. Keen ◽  
Neil Craven ◽  
F. John Bourne
Keyword(s):  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Human Neutrophils ◽  
Nadph Oxidase Activity

Two independent killing mechanisms of Candida albicans by human neutrophils: evidence from innate immunity defects

Blood ◽  
2014 ◽  
Vol 124 (4) ◽  
pp. 590-597 ◽  
Author(s):  
Roel P. Gazendam ◽  
John L. van Hamme ◽  
Anton T. J. Tool ◽  
Michel van Houdt ◽  
Paul J. J. H. Verkuijlen ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Candida Albicans ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Human Neutrophils ◽  
Nadph Oxidase Activity ◽  
Key Points

Key Points Human neutrophils use 2 independent mechanisms for the killing of unopsonized and serum-opsonized C albicans. Unopsonized Candida killing depends on CR3 and CARD9 but not dectin-1; opsonized Candida killing on FcγR, PKC, and NADPH oxidase activity.

scholarly journals IGF-I increases the expression of fibronectin by Nox4-dependent Akt phosphorylation in renal tubular epithelial cells

2012 ◽  
Vol 302 (1) ◽  
pp. C122-C130 ◽  
Author(s):  
David D. New ◽  
Karen Block ◽  
Basant Bhandhari ◽  
Yves Gorin ◽  
Hanna E. Abboud
Keyword(s):  
Epithelial Cells ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Dominant Negative ◽  
Tubular Epithelial Cells ◽  
Nadph Oxidase Activity ◽  
Akt Phosphorylation ◽  
Fibronectin Expression ◽  
Igf I

Extracellular matrix accumulation contributes to the progression of chronic kidney disease. Many growth factors including insulin-like growth factor-I (IGF-I) enhance matrix protein accumulation. Proximal tubular epithelial cells (PTCs) synthesize matrix proteins. NADPH oxidases are major sources of reactive oxygen species (ROS), important signaling molecules that mediate biological responses in a variety of cells and tissue. We investigated the mechanism by which IGF-I regulates fibronectin accumulation in PTCs and the role of a potential redox-dependent signaling pathway. IGF-I induces an increase in NADPH-dependent superoxide generation, enhances the release of hydrogen peroxide, and increases the expression of NADPH oxidase 4 (Nox4) in PTCs. IGF-I also stimulates phosphorylation of Akt, and inhibition of Akt or its upstream activator phosphatidylinositol 3-kinase attenuates IGF-I-induced fibronectin accumulation. Expression of dominant negative Akt also inhibits IGF-I-induced expression of fibronectin, indicating a role for this kinase in fibronectin accumulation. Expression of dominant negative adenovirus Nox4 inhibits IGF-I-induced NADPH oxidase activity, Akt phosphorylation, and fibronectin protein expression. Moreover, transfection of small interfering RNA targeting Nox4 decreases Nox4 protein expression and blocks IGF-I-induced Akt phosphorylation and the increase in fibronectin, placing Nox4 and ROS upstream of Akt signaling pathway. To confirm the role of Nox4, PTCs were infected with adenovirus construct expressing wild-type Nox4. Ad-Nox4, but not control Ad-green fluorescent protein, upregulated Nox4 expression and increased NADPH oxidase activity as well as fibronectin expression. Taken together, these results provide the first evidence for a role of Nox4 in IGF-I-induced Akt phosphorylation and fibronectin expression in tubular epithelial cells.

scholarly journals FcγR-stimulated activation of the NADPH oxidase: phosphoinositide-binding protein p40phox regulates NADPH oxidase activity after enzyme assembly on the phagosome

Blood ◽  
2008 ◽  
Vol 112 (9) ◽  
pp. 3867-3877 ◽  
Author(s):  
Wei Tian ◽  
Xing Jun Li ◽  
Natalie D. Stull ◽  
Wenyu Ming ◽  
Chang-Il Suh ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Superoxide Production ◽  
Resting Cells ◽  
Cellular Activation ◽  
Nadph Oxidase Activity ◽  
Phagocyte Nadph Oxidase ◽  
Before And After ◽  
Membrane Bound

AbstractThe phagocyte NADPH oxidase generates superoxide for microbial killing, and includes a membrane-bound flavocytochrome b558 and cytosolic p67phox, p47phox, and p40phox subunits that undergo membrane translocation upon cellular activation. The function of p40phox, which binds p67phox in resting cells, is incompletely understood. Recent studies showed that phagocytosis-induced superoxide production is stimulated by p40phox and its binding to phosphatidylinositol-3-phosphate (PI3P), a phosphoinositide enriched in membranes of internalized phagosomes. To better define the role of p40phox in FcγR-induced oxidase activation, we used immunofluorescence and real-time imaging of FcγR-induced phagocytosis. YFP-tagged p67phox and p40phox translocated to granulocyte phagosomes before phagosome internalization and accumulation of a probe for PI3P. p67phox and p47phox accumulation on nascent and internalized phagosomes did not require p40phox or PI3 kinase activity, although superoxide production before and after phagosome sealing was decreased by mutation of the p40phox PI3P-binding domain or wortmannin. Translocation of p40phox to nascent phagosomes required binding to p67phox but not PI3P, although the loss of PI3P binding reduced p40phox retention after phagosome internalization. We conclude that p40phox functions primarily to regulate FcγR-induced NADPH oxidase activity rather than assembly, and stimulates superoxide production via a PI3P signal that increases after phagosome internalization.

Novel Role of Protein Disulfide Isomerase in the Regulation of NADPH Oxidase Activity: Pathophysiological Implications in Vascular Diseases

2008 ◽  
Vol 10 (6) ◽  
pp. 1101-1114 ◽  
Author(s):  
Francisco R.M. Laurindo ◽  
Denise C. Fernandes ◽  
Angélica M. Amanso ◽  
Lucia R. Lopes ◽  
Célio X.C. Santos
Keyword(s):  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Protein Disulfide Isomerase ◽  
Vascular Diseases ◽  
Disulfide Isomerase ◽  
Nadph Oxidase Activity ◽  
Protein Disulfide

scholarly journals Relation of human neutrophil phorbol ester receptor occupancy and NADPH- oxidase activity

Blood ◽  
1982 ◽  
Vol 60 (2) ◽  
pp. 333-339 ◽  
Author(s):  
AI Tauber ◽  
DB Brettler ◽  
EA Kennington ◽  
PM Blumberg
Keyword(s):  
Nadph Oxidase ◽  
Phorbol Ester ◽  
Respiratory Burst ◽  
Human Neutrophil ◽  
Oxidase Activity ◽  
Receptor Occupancy ◽  
Human Neutrophils ◽  
Binding Studies ◽  
Nadph Oxidase Activity ◽  
Phorbol Ester Receptor

Abstract Phorbol esters are potent stimulants of the respiratory burst of the human neutrophil as assessed by superoxide (O2-) generation in whole cells and by NADPH-oxidase activity in a broken-cell 27,000-g particulate fraction. Phorbol 12-myristate, 13-acetate (PMA) and phorbol 12,13-dibutyrate (PDBu) stimulate production of O2- by human neutrophils with ED50 concentrations of 3.9 +/- 2.1 and 41.7 +/- 7.1 nM, respectively. The relation of biologic activity to receptor occupancy was assessed with binding studies of PMA and PDBu. Phorbol ester binding revealed a single high affinity phorbol ester receptor present at 7.6 x 10(5) sites/cell. The binding affinities for PMA and PDBu, 4.9 nM and 38.4 nM, respectively, agreed quantitatively with that of biologic potencies. Because of the high concentration of phorbol ester receptors (up to 125 nM) and the large amount of nonspecific binding at high cell density, apparent discrepancies between ED50′s for NADPH-oxidase and whole cell O2- generation were noted. With the use of low cell concentrations, quantitative agreement between intact cell production of O2-, NADPH-oxidase activity, and receptor binding was found. These results further support the identity of the NADPH-oxidase as the enzymatic source of respiratory burst O2- production in human neutrophils.

scholarly journals Composition of partially purified NADPH oxidase from pig neutrophils

1984 ◽  
Vol 223 (3) ◽  
pp. 639-648 ◽  
Author(s):  
P Bellavite ◽  
O T G Jones ◽  
A R Cross ◽  
E Papini ◽  
F Rossi
Keyword(s):  
Enzyme Activity ◽  
Cytochrome C ◽  
Nadph Oxidase ◽  
Cytochrome B ◽  
Oxidase Activity ◽  
Gel Filtration ◽  
Purification Procedure ◽  
Nadph Oxidase Activity ◽  
Cytochrome C Reductase

The superoxide (O2.-)-forming enzyme NADPH oxidase from pig neutrophils was solubilized and partially purified by gel-filtration chromatography. The purification procedure allowed the separation of NADPH oxidase activity from NADH-dependent cytochrome c reductase and 2,6-dichlorophenol-indophenol reductase activities. O2.-forming activity was co-purified with cytochrome b-245 and was associated with phospholipids. However, active fractions endowed with cytochrome b were devoid of ubiquinone and contained only little FAD. The cytochrome b/FAD ratio was 1.13:1 in the crude solubilized extract and increased to 18.95:1 in the partially purified preparations. Most of FAD was associated with fractions containing NADH-dependent oxidoreductases. These results are consistent with the postulated role of cytochrome b in O2.-formation by neutrophil NADPH oxidase, but raise doubts about the participation of flavoproteins in this enzyme activity.

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