scholarly journals The phosphoinositide-binding protein p40phox activates the NADPH oxidase during FcγIIA receptor–induced phagocytosis

2006 ◽  
Vol 203 (8) ◽  
pp. 1915-1925 ◽  
Author(s):  
Chang-Il Suh ◽  
Natalie D. Stull ◽  
Xing Jun Li ◽  
Wei Tian ◽  
Marianne O. Price ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Kinase Inhibitors ◽  
Point Mutations ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Enzyme Activation ◽  
Superoxide Production ◽  
Px Domain ◽  
Flavocytochrome B558 ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Phosphatidylinositol 3

Superoxide produced by the phagocyte reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is essential for host defense. Enzyme activation requires translocation of p67phox, p47phox, and Rac-GTP to flavocytochrome b558 in phagocyte membranes. To examine the regulation of phagocytosis-induced superoxide production, flavocytochrome b558, p47phox, p67phox, and the FcγIIA receptor were expressed from stable transgenes in COS7 cells. The resulting COSphoxFcγR cells produce high levels of superoxide when stimulated with phorbol ester and efficiently ingest immunoglobulin (Ig)G-coated erythrocytes, but phagocytosis did not activate the NADPH oxidase. COS7 cells lack p40phox, whose role in the NADPH oxidase is poorly understood. p40phox contains SH3 and phagocyte oxidase and Bem1p (PB1) domains that can mediate binding to p47phox and p67phox, respectively, along with a PX domain that binds to phosphatidylinositol-3-phosphate (PI(3)P), which is generated in phagosomal membranes. Expression of p40phox was sufficient to activate superoxide production in COSphoxFcγR phagosomes. FcγIIA-stimulated NADPH oxidase activity was abrogated by point mutations in p40phox that disrupt PI(3)P binding, or by simultaneous mutations in the SH3 and PB1 domains. Consistent with an essential role for PI(3)P in regulating the oxidase complex, phagosome NADPH oxidase activation in primary macrophages ingesting IgG-coated beads was inhibited by phosphatidylinositol 3 kinase inhibitors to a much greater extent than phagocytosis itself. Hence, this study identifies a role for p40phox and PI(3)P in coupling FcγR-mediated phagocytosis to activation of the NADPH oxidase.

Creation of a genetic system for analysis of the phagocyte respiratory burst: high-level reconstitution of the NADPH oxidase in a nonhematopoietic system

Blood ◽  
2002 ◽  
Vol 99 (8) ◽  
pp. 2653-2661 ◽  
Author(s):  
Marianne O. Price ◽  
Linda C. McPhail ◽  
J. David Lambeth ◽  
Chang-Hoon Han ◽  
Ulla G. Knaus ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Enzyme Activation ◽  
Superoxide Production ◽  
Reduced Form ◽  
Human Neutrophils ◽  
Nadph Oxidase Activity ◽  
High Level

Abstract The phagocyte nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH) oxidase was functionally reconstituted in monkey kidney COS-7 cells by transfection of essential subunits, gp91phox, p22phox, p47phox, and p67phox. COS-7 cells express the essential small guanosine 5′-triphosphatase, Rac1. Transgenic COS-phox cells were capable of arachidonic acid–induced NADPH oxidase activity up to 80% of that of human neutrophils, and of phorbol myristate acetate (PMA)–induced activity up to 20% of that of neutrophils. Expression of all 4 phox components was required for enzyme activity, and enzyme activation was associated with membrane translocation of p47phox, p67phox, and Rac1. Expression of p47phox Ser303Ala/Ser304Ala or Ser379Ala phosphorylation-deficient mutants resulted in significantly impaired NAPDH oxidase activity, compared with expression of wild-type p47phox or the p47phox Ser303Glu/Ser304Glu phosphorylation mimic, suggesting that p47phoxphosphorylation contributes to enzyme activity in the COS system, as is the case in neutrophils. Hence, COS-phox cells should be useful as a new whole-cell model that is both capable of high-level superoxide production and readily amenable to genetic manipulation for investigation of NADPH oxidase function. PMA-elicited superoxide production in COS-phox cells was regulated by activation of protein kinase C (PKC) and Rac. Although COS-7 cells differ from human neutrophils in PKC isoform expression, transient expression of major neutrophil isoforms in COS-phox cells did not increase PMA-induced superoxide production, suggesting that endogenous isoforms were not rate limiting. Val204 in p67phox, previously shown to be required for NADPH oxidase activity under cell-free conditions, was found to be essential for superoxide production by intact COS-phox cells, on the basis of transfection studies using a p67phox(Val204Ala) mutant.

NADPH oxidase promotes NF-κB activation and proliferation in human airway smooth muscle

2002 ◽  
Vol 282 (4) ◽  
pp. L782-L795 ◽  
Author(s):  
Sukhdev S. Brar ◽  
Thomas P. Kennedy ◽  
Anne B. Sturrock ◽  
Thomas P. Huecksteadt ◽  
Mark T. Quinn ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Nadph Oxidase ◽  
Airway Smooth Muscle ◽  
Nicotinamide Adenine Dinucleotide ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nuclear Factor Κb ◽  
Nicotinamide Adenine ◽  
Phagocytic Cells ◽  
Diphenylene Iodonium ◽  
Reduced Nicotinamide Adenine Dinucleotide

Evidence is rapidly accumulating that low-activity-reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases homologous to that in phagocytic cells generate reactive oxygen species as signaling intermediates in both endothelium and vascular smooth muscle. We therefore explored the possibility of such an oxidase regulating growth of airway smooth muscle (AWSM). Proliferation of human AWSM cells in culture was inhibited by the antioxidants catalase and N-acetylcysteine, and by the flavoprotein inhibitor diphenylene iodonium (DPI). Membranes prepared from human AWSM cells generated superoxide anion (O[Formula: see text]) measured by superoxide dismutase-inhibitable lucigenin chemiluminescence, with a distinct preference for NADPH instead of reduced nicotinamide adenine dinucleotide as substrate. Chemiluminescence was also inhibited by DPI, suggesting the presence of a flavoprotein containing oxidase generating O[Formula: see text] as a signaling molecule for cell growth. Examination of human AWSM cells by reverse transcriptase-polymerase chain reaction consistently demonstrated transcripts with sequences identical to those reported for p22phox. Transfection with p22phoxantisense oligonucleotides reduced human AWSM proliferation. Inhibition of NADPH oxidase activity with DPI prevented serum-induced activation of nuclear factor-κB (NF-κB), and overexpression of a superrepressor form of the NF-κB inhibitor IκBα significantly reduced human AWSM growth. These findings suggest that an NADPH oxidase containing p22phoxregulates growth-factor responsive human AWSM proliferation, and that the oxidase signals in part through activation of the prototypical redox-regulated transcription factor NF-κB.

scholarly journals A new genetic subgroup of chronic granulomatous disease with autosomal recessive mutations in p40phox and selective defects in neutrophil NADPH oxidase activity

Blood ◽  
2009 ◽  
Vol 114 (15) ◽  
pp. 3309-3315 ◽  
Author(s):  
Juan D. Matute ◽  
Andres A. Arias ◽  
Nicola A. M. Wright ◽  
Iwona Wrobel ◽  
Christopher C. M. Waterhouse ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Chronic Granulomatous Disease ◽  
Oxidase Activity ◽  
Autosomal Recessive ◽  
Premature Stop Codon ◽  
Superoxide Production ◽  
Human Neutrophils ◽  
Granulomatous Disease ◽  
Recessive Mutations ◽  
Px Domain

Abstract Chronic granulomatous disease (CGD), an immunodeficiency with recurrent pyogenic infections and granulomatous inflammation, results from loss of phagocyte superoxide production by recessive mutations in any 1 of 4 genes encoding subunits of the phagocyte NADPH oxidase. These include gp91phox and p22phox, which form the membrane-integrated flavocytochrome b, and cytosolic subunits p47phox and p67phox. A fifth subunit, p40phox, plays an important role in phagocytosis-induced superoxide production via a phox homology (PX) domain that binds to phosphatidylinositol 3-phosphate (PtdIns(3)P). We report the first case of autosomal recessive mutations in NCF4, the gene encoding p40phox, in a boy who presented with granulomatous colitis. His neutrophils showed a substantial defect in intracellular superoxide production during phagocytosis, whereas extracellular release of superoxide elicited by phorbol ester or formyl-methionyl-leucyl-phenylalanine (fMLF) was unaffected. Genetic analysis of NCF4 showed compound heterozygosity for a frameshift mutation with premature stop codon and a missense mutation predicting a R105Q substitution in the PX domain. Parents and a sibling were healthy heterozygous carriers. p40phoxR105Q lacked binding to PtdIns(3)P and failed to reconstitute phagocytosis-induced oxidase activity in p40phox-deficient granulocytes, with premature loss of p40phoxR105Q from phagosomes. Thus, p40phox binding to PtdIns(3)P is essential for phagocytosis-induced oxidant production in human neutrophils and its absence can be associated with disease.

The Phosphoinositide-Binding Protein p40phox Regulates NADPH Oxidase Activation Rather Than Assembly during FcγIIA Receptor-Induced Phagocytosis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 678-678 ◽  
Author(s):  
Wei Tian ◽  
Xing Jun Li ◽  
Natalie D. Stull ◽  
Chang-Il Suh ◽  
Sergio Grinstein ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Superoxide Production ◽  
Null Mouse ◽  
Target Sequence ◽  
Resting Cells ◽  
Nadph Oxidase Activity ◽  
Px Domain ◽  
Significant Difference ◽  
Nadph Oxidase Activation

Abstract Many critical features of the organization and regulation of the phagocyte NADPH oxidase, a complex multi-subunit enzyme that generates superoxide for microbial killing, remain poorly defined. The active enzyme includes a membrane-bound flavocytochrome b along with p47phox, p67phox, p40phox, and Rac-GTP that are present in the cytosol of resting cells. p67phox is linked by high affinity interactions with both p47phox and p40phox, which appear to translocate as a trimeric complex upon cellular activation. The p47phox subunit acts as an adaptor to promote translocation by docking at a proline-rich target sequence on the flavocytochrome, and p67phox is a Rac-GTP effector containing a domain that activates electron transport. In contrast, the function of p40phox, which is not required for high level oxidase activity in cell free systems, is poorly understood. Recently, our group showed that p40phox plays key role in the activation of superoxide production during phagocytosis of IgG-opsonized targets in COSphoxFcγR cells. This model cell line contains stable transgenes for the flavocytochrome, p47phox, p67phox, and the FcγIIA receptor, without or with an additional transgene for p40phox. p40phox-dependent coupling of FcγR-mediated phagocytosis to superoxide production required an intact p40phox PX domain, which binds to phosphatidylinositol-3-phosphate (PI3P), a phosphoinositide generated by class III PI3 kinases in phagosome membranes (Suh et al J Exp Med 203, 1915Suh et al J Exp Med 203, 2006). Furthermore, a newly developed p40phox-null mouse exhibits reduced neutrophil NADPH oxidase activity in response to selected agonists, including IgG-opsonized targets (Ellson et al J Exp Med 203, 1927Ellson et al J Exp Med 203, 2006). In the current study, we investigated whether p40phox is required for translocation of p67phox during phagocytosis. We generated COSphoxFcγR cells expressing YFP-tagged p67phox from a stable transgene instead of untagged p67phox. Following incubation with IgG-opsonized sheep red blood cells (IgG-RBC), p67phox was detected on phagosome membranes at both early stages of phagosome cup formation and after closure, independent of whether or not p40phox was also co-expressed. However, NADPH oxidase activity was not detected in IgG-RBC phagosomes in COSphoxFcγR-p67phox-YFP cells unless p40phox was present. PMA-activated superoxide production was independent of p40phox, and Western blotting indicated there was no significant difference in expression of the other oxidase subunits in COSphoxFcγR-p67phox-YFP cells without or with the p40phox transgene. Further studies in PLB-985 granulocytes expressing stable transgenes for either YFP-tagged p67phox or p40phox showed that the PI3K inhibitor wortmannin inhibited phagosome NADPH oxidase activity and translocation of p40phox, but localization of p67phox to phagosomes was unaffected. These results indicate that although p40phox positively regulates NADPH oxidase activation during phagocytosis, recruitment of p67phox to the phagosome is independent of p40phox. Taken together, these data suggest that the PX domain of p40phox acts as a PI3P-dependent switch to activate the membrane-assembled NADPH oxidase complex.

Current molecular models for NADPH oxidase regulation by Rac GTPase

Blood ◽  
2002 ◽  
Vol 100 (8) ◽  
pp. 2692-2695 ◽  
Author(s):  
Gary M. Bokoch ◽  
Becky A. Diebold
Keyword(s):  
Nadph Oxidase ◽  
Host Defense ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Oxygen Species ◽  
Molecular Models ◽  
Rac Gtpase ◽  
Rho Family Gtpases ◽  
Rho Family ◽  
Guanosine Triphosphatase ◽  
Reduced Nicotinamide Adenine Dinucleotide

Reactive oxygen species (ROS) have been increasingly recognized as important components of cell signaling in addition to their well-established roles in host defense. The formation of ROS in phagocytic and nonphagocytic cells involves membrane-localized and Rac guanosine triphosphatase (GTPase)–regulated reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase(s). We discuss here the current molecular models for Rac GTPase action in the control of the phagocytic leukocyte NADPH oxidase. As a mechanistically detailed example of Rac GTPase signaling, the NADPH oxidase provides a potential paradigm for signaling by Rho family GTPases in general.

Activation and priming of neutrophil nicotinamide adenine dinucleotide phosphate oxidase and phospholipase A2 are dissociated by inhibitors of the kinases p42ERK2and p38SAPK and by methyl arachidonyl fluorophosphonate, the dual inhibitor of cytosolic and calcium-independent phospholipase A2

Blood ◽  
2001 ◽  
Vol 97 (8) ◽  
pp. 2469-2477 ◽  
Author(s):  
Elahe Mollapour ◽  
David C. Linch ◽  
Pamela J. Roberts
Keyword(s):  
Nadph Oxidase ◽  
Phospholipase A2 ◽  
Nicotinamide Adenine Dinucleotide ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Superoxide Production ◽  
Dual Inhibitor ◽  
Nadph Oxidase Activity ◽  
Gm Csf ◽  
Tnf Α ◽  
Arachidonate Release

Abstract Arachidonic acid (AA) generated by phospholipase A2(PLA2) is thought to be an essential cofactor for phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. Both enzymes are simultaneously primed by cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor–α (TNF-α). The possibility that either unprimed or cytokine-primed responses of PLA2 or NADPH oxidase to the chemotactic agents formyl-methionyl-leucyl-phenylalanine (FMLP) and complement factor 5a (C5a) could be differentially inhibited by inhibitors of the mitogen-activated protein (MAP) kinase family members p42ERK2 (PD98059) and p38SAPK(SB203580) was investigated. PD98059 inhibited the activation of p42ERK2 by GM-CSF, TNF-α, and FMLP, but it did not inhibit FMLP-stimulated superoxide production in either unprimed or primed neutrophils. There was no significant arachidonate release from unprimed neutrophils stimulated by FMLP, and arachidonate release stimulated by calcium ionophore A23187 was not inhibited by PD98059. In contrast, PD98059 inhibited both TNF-α– and GM-CSF–primed PLA2 responses stimulated by FMLP. On the other hand, SB203580 inhibited FMLP-superoxide responses in unprimed as well as TNF-α– and GM-CSF–primed neutrophils, but failed to inhibit TNF-α– and GM-CSF–primed PLA2 responses stimulated by FMLP, and additionally enhanced A23187-stimulated arachidonate release, showing that priming and activation of PLA2 and NADPH oxidase are differentially dependent on both the p38SAPK and p42ERK2 pathways. Studies using C5a as an agonist gave similar results and confirmed the findings with FMLP. In addition, methyl arachidonyl fluorophosphonate (MAFP), the dual inhibitor of c and iPLA2 enzymes, failed to inhibit superoxide production in primed cells at concentrations that inhibited arachidonate release. These data demonstrate that NADPH oxidase activity can be dissociated from AA generation and indicate a more complex role for arachidonate in neutrophil superoxide production.

scholarly journals Roles of Phosphatidylinositol 3-Kinase-Akt and NADPH Oxidase in Adenosine 5′-Triphosphate–Sensitive K + Channel Function Impaired by High Glucose in the Human Artery

Hypertension ◽  
2008 ◽  
Vol 52 (3) ◽  
pp. 507-513 ◽  
Author(s):  
Hiroyuki Kinoshita ◽  
Naoyuki Matsuda ◽  
Hikari Kaba ◽  
Noboru Hatakeyama ◽  
Toshiharu Azma ◽  
...  
Keyword(s):  
High Glucose ◽  
Nicotinamide Adenine Dinucleotide ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nicotinamide Adenine ◽  
Akt Pathway ◽  
Phosphatidylinositol 3 Kinase ◽  
Human Artery ◽  
Channel Function ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Phosphatidylinositol 3

The present study was designed to examine roles of the phosphatidylinositol 3-kinase-Akt pathway and reduced nicotinamide-adenine dinucleotide phosphate oxidases in the reduced ATP-sensitive K + channel function via superoxide produced by high glucose in the human artery. We evaluated the activity of the phosphatidylinositol 3-kinase-Akt pathway, as well as reduced nicotinamide-adenine dinucleotide phosphate oxidases, the intracellular levels of superoxide and ATP-sensitive K + channel function in the human omental artery without endothelium. Levels of the p85-α subunit and reduced nicotinamide-adenine dinucleotide phosphate oxidase subunits, including p47phox, p22phox, and Rac-1, increased in the membrane fraction from arteries treated with d -glucose (20 mmol/L) accompanied by increased intracellular superoxide production. High glucose simultaneously augmented Akt phosphorylation at Ser 473, as well as Thr 308 in the human vascular smooth muscle cells. A phosphatidylinositol 3-kinase inhibitor LY294002, as well as tiron and apocynin, restored vasorelaxation and hyperpolarization in response to an ATP-sensitive K + channel opener levcromakalim. Therefore, it can be concluded that the activation of the phosphatidylinositol 3-kinase-Akt pathway, in combination with the translocation of p47phox, p22phox, and Rac-1, contributes to the superoxide production induced by high glucose, resulting in the impairment of ATP-sensitive K + channel function in the human visceral artery.

scholarly journals Neutrophils from p40phox−/− mice exhibit severe defects in NADPH oxidase regulation and oxidant-dependent bacterial killing

2006 ◽  
Vol 203 (8) ◽  
pp. 1927-1937 ◽  
Author(s):  
Chris D. Ellson ◽  
Keith Davidson ◽  
G. John Ferguson ◽  
Rod O'Connor ◽  
Len R. Stephens ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Critical Role ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Phagocytic Cells ◽  
Bacterial Killing ◽  
Catalytic Core ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Factor Α

The generation of reactive oxygen species (ROS) by the reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex plays a critical role in the antimicrobial functions of the phagocytic cells of the immune system. The catalytic core of this oxidase consists of a complex between gp91phox, p22phox, p47phox, p67phox, p40phox, and rac-2. Mutations in each of the phox components, except p40phox, have been described in cases of chronic granulomatous disease (CGD), defining their essential role in oxidase function. We sought to establish the role of p40phox by investigating the NADPH oxidase responses of neutrophils isolated from p40phox−/− mice. In the absence of p40phox, the expression of p67phox is reduced by ∼55% and oxidase responses to tumor necrosis factor α/fibrinogen, immunoglobulin G latex beads, Staphylococcus aureus, formyl-methionyl-leucyl-phenylalanine, and zymosan were reduced by ∼97, 85, 84, 75, and 30%, respectively. The defect in ROS production by p40phox−/− neutrophils in response to S. aureus translated into a severe, CGD-like defect in the killing of this organism both in vitro and in vivo, defining p40phox as an essential component in bacterial killing.

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