Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.3.1 (NADPH oxidase)
11,281 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Over 170 years ago Metchnikoff described the bacteriocidal activity of leukocytes. It has been clarified that leukocytes play an important role in first defense mechanism against infection due to microorganism. Leukocytes immigrate to the lesion, which various microorganisms invade across mucosal barrier, and phagocyte and kill ingested microorganisms. The inability of the chronic granulomatous disease (CGD) granulocytes to generate superoxide has prompted the analysis of NADPH oxidase responsible for superoxide generation. The study on CGD has provided profound informations into NADPH oxidase system of leukocytes. Recruitment leukocytes to inflammatory lesion is essential for the inflammatory process, and it is regulated by various chemotactic factors and the adhesion molecules interaction between leukocytes and endothelium of vessels. Identification of interleukin-8 (IL-8) to be one of chemotactic cytokines and its gene cloning offered the progressive understanding for the immigration mechanism of leukocytes from vessels to inflammatory lesion. On the other hand, LFA-1 deficiency revealed that emigration, adhesion and phagocytosis of leukocytes are associated closely with the adhesion molecules on their surfaces. More recently, the cytokine networks of myelopoiesis or inflammatory process have been clarified. Among various cytokines, the cloning of G-CSF has provided the clinical application of rhG-CSF for neutropenic patients who may be induced by the treatment with anticancer agents. This symposium focused on above-mentioned items for an important aspect of neutrophil research.
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PMID:[Progress of leukocyte research]. 159 63

f-Met-Leu-Phe-stimulated luminol-enhanced chemiluminescence was found to be repeatedly defective in some MDS patients. This defect was not attributed to myeloperoxidase deficiency, nor to a defect in NADPH oxidase function, because PMA chemiluminescence was found to be normal in these individuals. An arbitrary value of 7 mV (half the mean control value) was chosen to subdivide the group: MDS patients with values < 7 mV had a mean f-Met-Leu-Phe chemiluminescence response of 2.5 +/- 0.5 compared to MDS patients with values > 7 mV who had a mean response of 15.6 +/- 1.6 mV, P < 0.01 (healthy controls 14 +/- 2 mV). The characteristics of the f-Met-Leu-Phe receptor and initial calcium flux results suggested that the receptor itself was normal in number and function in low f-Met-Leu-Phe responders. The rate of superoxide generation, which is calcium-dependent, was also found to be in the normal range in low f-Met-Leu-Phe responders, although total superoxide production was reduced in some of these patients. When MDS neutrophils with a low f-Met-Leu-Phe response were stimulated with PMA, chemiluminescence was normal, suggesting normal activity of the NADPH-oxidase complex. Furthermore, myeloperoxidase activity was reduced in only three out of the 11 low f-Met-Leu-Phe responders. Following priming with GM-CSF, f-Met-Leu-Phe chemiluminescence was 27 +/- 1.6 mV in low f-Met-Leu-Phe responders compared to controls (87.7 +/- 11 mV, P < 0.005). Thus, although responses were improved, they were not as marked as in control neutrophils. These data suggest that a subgroup of MDS patients have a low f-Met-Leu-Phe chemiluminescence response which is not due to a defect in the f-Met-Leu-Phe receptor or oxidase activity, and in the majority of cases MPO activity is normal. Initial patient survival data suggest that these patients may have an increased risk of infective mortality. It is proposed that defective f-Met-Leu-Phe chemiluminescence results from a putative defect in cell-signalling mechanism upstream of PKC, and GM-CSF priming only partially improves responsiveness.
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PMID:Identification of a subgroup of myelodysplastic patients with a neutrophil stimulation-signalling defect. 791 69

We have investigated the relationship between the expression of the p47-phox and p67-phox cytosolic components of the NADPH oxidase and priming of the macrophage respiratory burst. Western blot analysis revealed that murine bone marrow-derived macrophages (BMM) contain immunoreactive proteins detected by antisera raised against recombinant human p47-phox and p67-phox. Priming BMM by exposure to tumor necrosis factor alpha (TNF-alpha) or lipopolysaccharide (LPS) increased the levels of p47-phox and p67-phox. Colony-stimulating factor 1 (CSF-1), which we previously found to have a negative effect on the priming of murine macrophages, had no effect on the level of p47-phox but down-regulated that of p67-phox. Our results suggest that the regulatory effects of LPS, TNF-alpha, and CSF-1 on the respiratory burst of BMM may be due to modulation of the expression of the p47-phox and p67-phox cytosolic components of the NADPH oxidase.
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PMID:Expression of p47-phox and p67-phox proteins in murine bone marrow-derived macrophages: enhancement by lipopolysaccharide and tumor necrosis factor alpha but not colony stimulating factor 1. 814 24

PMN obtained from asthmatic subjects demonstrate a heightened respiratory burst with increased superoxide generation compared to normals. This enhanced superoxide anion generation could be secondary to increased activity of the respiratory burst NADPH oxidase or diminished metabolism of superoxide via superoxide dismutase (SOD). The two forms of SOD expressed in PMN, CuZnSOD expressed constitutively in the cytosol and inducible mitochondrial MnSOD, were investigated in asthmatics. Resting PMN from asthmatics (N = 9) contained significantly less MnSOD activity compared to controls (0.46 +/- 0.16 vs. 0.79 +/- 0.17 units/10(7) PMN, respectively; P = 0.0002). As several cytokines including interleukins (IL) -1, -4, and -6 as well as granulocyte macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF) enhance the PMN respiratory burst and are synthesized in the asthmatic lung, their effects on PMN MnSOD activity were assayed. In contrast to its effects on lymphocytes, both IL-1 and IL-6 significantly inhibited in a dose-dependent fashion the induction of MnSOD in PMN from normals (0.42 +/- 0.12 and 0.45 +/- 0.05 units/10(7) PMN, respectively, at 10 units/ml of each cytokine; P = 0.02 compared to resting cells) but failed to further modulate MnSOD production in asthmatic PMN. IL-4 and GM-CSF had no effect on MnSOD production, and TNF effects could not be studied because of its effects on cell viability. There were no differences in the activity of CuZnSOD (N = 9) or NADPH oxidase (N = 4) in the two groups. Inhibition of MnSOD activity in PMN secondary to cytokine exposure in the asthmatic lung could explain, at least in part, the increased generation of superoxide from PMN obtained from asthmatics. This would promote the presence and severity of inflammation in the asthmatic lung. These data further support a role for IL-1 and IL-6 in allergic inflammation.
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PMID:Activities of superoxide dismutases and NADPH oxidase in neutrophils obtained from asthmatic and normal donors. 839 94

Platelet-PMN interactions have been extensively studied and a spectrum of possible effects has been demonstrated. However, the physiological relevance of many of the observed in vitro phenomena remains obscure. Here we report a novel, and potentially pathophysiologically important, mechanism by which platelets can enhance PMN reactivity. We first observed that addition of platelets to PMN suspensions enhanced the chemiluminescence response of PMN to FMLP. This enhancement occurred without augmentation of superoxide generation and did not involve mutual platelet-PMN adhesion. The soluble material responsible was biochemically and immunologically identified as PF4 derived from platelet alpha-granules. The alpha-granule release was shown to be selective and required minimal platelet stimulation. Since the PF4 effect did not influence NADPH oxidase activation, it differed markedly from that of other priming agents such as GM-CSF. Further studies showed that the PF4 effect was attributable entirely to the surface translocation and secretion of primary granule myeloperoxidase. There was marked synergy between PF4 and GM-CSF and both were required for maximal potentiation of PMN reactivity. These results demonstrate that PF4 and GM-CSF employ different pathways in PMN priming. The ease with which platelets could release PF4 at sites of vessel-wall damage and inflammation suggests that platelet-PMN interaction via PF4 is likely to be of major pathophysiological importance.
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PMID:Platelets prime PMN via released PF4: mechanism of priming and synergy with GM-CSF. 854 28

Incubation of neutrophils with cytokines such as granulocyte macrophage colony-stimulating factor (GM-CSF) delays their loss of function and changes in cellular morphology that are characteristic of apoptosis. Adenosine triphosphate (ATP) and the diadenosine polyphosphates Ap4A and AP3A were almost as effective as GM-CSF in delaying neutrophil apoptosis. The nucleotides could thus preserve cellular morphology, protect against chromatin fragmentation, and preserve functions such as NADPH oxidase activity and expression of CD16. Moreover, addition of ATP, AP3A and AP4A together with GM-CSF resulted in more pronounced protection from apoptosis than was observed during incubation with either the cytokine or the nucleotides alone. Because ATP, Ap3A, and AP4A may be secreted from activated platelets, these observations suggest that platelet-derived products, perhaps acting in combination with endothelial-derived or immune cell-derived cytokines, can regulate neutrophil function during certain types of inflammation.
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PMID:The diadenosine polyphosphates Ap3A and Ap4A and adenosine triphosphate interact with granulocyte-macrophage colony-stimulating factor to delay neutrophil apoptosis: implications for neutrophil: platelet interactions during inflammation. 860 63

Polymorphonuclear neutrophils play an important role against pathogens through the production of toxic oxygen metabolites by the NADPH oxidase enzyme, which reduces oxygen to superoxide anion in the respiratory burst. Neutropenia, infectious complications and impaired neutrophil function are often reported in glycogen storage disease type Ib (GSDIb), a metabolic disorder characterized by increased glycogen and decreased glucose-6-phosphatase (G-6-P) activity in the liver. Two children with GSDIb and associated neutropenia with recurrent bacterial infections were treated daily with different doses of rHu-GM-CSF. NADPH oxidase activity and chemotaxis in patients were assessed before and during therapy in stimulated and unstimulated neutrophils. During rHu-GM-CSF treatment, any increase found in the NADPH oxidase activity of patients was not significant with respect to that in controls. In one patient chemotaxis was greater than of controls. This finding suggests that in patients with GSDIb both neutropenia and PMN abnormalities may be responsible for infections, and PMN dysfunction probably depends on the degree of inherited functional G-6-P deficit.
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PMID:NADPH oxidase activity and chemotaxis by neutrophils in two patients with glycogen storage disease type Ib treated with recombinant human granulocyte-monocyte colony-stimulating factor. 864 44

Small numbers of CD34+ primitive hematopoietic progenitors are found in normal human peripheral blood. These cells differentiate to myeloid or lymphoid lineage under the influence of growth factors. We investigated the effects of IL5 and other growth factors on the production of eosinophils from peripheral blood CD34+ cells. CD34+ cells were plated in agarose with different combinations of cytokines. At 14 days of growth a triple stain technique was used to identify eosinophil, monocyte and neutrophil colonies. IL5 alone did not support colony growth. In contrast GM-CSF and IL3 alone or together supported the generation of more than 50% eosinophil colonies. Addition of IL5 increased the fraction of eosinophil colonies to over 70%. Under the best conditions (IL3 + GM-CSF + IL5), the addition of interferon-a or LPS inhibited colony growth by 51% and 58%, respectively. Since IL5 alone did not support colony growth from CD34+ cells, we determined when IL5 responsive cells appeared in culture. Cells were grown initially with IL3 + GM-CSF, washed, and plated with IL5 alone. Only when progenitors were grown at least 3 days, could IL5 serve as the single growth factor supporting pure eosinophil colony growth (47 colonies/104 cells plated at day 3 and 134 colonies/104 cells at day 7). Growth of CD34+ in liquid culture for 28 days in the presence of IL3, GM-CSF and IL5 resulted in almost 250 fold increase in cell number, yielding a population of 83% maturing eosinophils. We used our culture system and the sensitive technique of RT-PCR to analyze the kinetics of production of mRNA transcripts encoding several eosinophil proteins. Freshly isolated CD34+ cells contained no eosinophil granule protein transcripts and barely detectable amounts of some oxidase protein transcripts. At day 3 of culture no cells recognizable by histochemical staining as eosinophils could be detected, but transcripts for all five eosinophil granule proteins were present. These transcripts increased several fold during the entire culture period. Similar kinetics were seen for the NADPH oxidase protein transcripts. These studies demonstrate that within 3 days of culture, peripheral blood CD34+ cells can become committed to the eosinophil lineage as demonstrated by responsiveness to IL5 and production of specific protein transcripts.
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PMID:Growth and differentiation of eosinophils from human peripheral blood CD 34+ cells. 902 88

Soluble immune complexes activate a rapid burst of reactive oxidant secretion from neutrophils that have previously been primed with GM-CSF. Binding of these complexes to the cell surface of unprimed neutrophils results in the generation of intracellular Ca2+ transients, but the NADPH oxidase fails to become activated. No phospholipase D activity was observed following the addition of soluble immune complexes to unprimed cells. Upon priming with GM-CSF, the intracellular Ca2+ signal generated following soluble complex binding was greatly extended and phospholipase D was activated: there was also increased phosphorylation of proteins on tyrosine residues and the NADPH oxidase was activated. When Ca2+ influx was prevented, this phospholipase D activity was not observed. This primed oxidase activity was completely inhibited by erbstatin. Treatment of unprimed neutrophils with pervanadate (to inhibit protein tyrosine phosphatases) mimicked the effects of priming in that pervanadate-treated neutrophils secreted reactive oxidants in response to soluble immune complexes. The data indicate that during priming a new signaling pathway is activated that involves Ca2+ influx, phosphorylation on tyrosine residues, phospholipase D activity, and NADPH oxidase activation.
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PMID:Stimulation of primed neutrophils by soluble immune complexes: priming leads to enhanced intracellular Ca2+ elevations, activation of phospholipase D, and activation of the NADPH oxidase. 964 77

Neutrophil superoxide production can be potentiated by prior exposure to "priming" agents such as granulocyte/macrophage colony stimulating factor (GM-CSF). Because the mechanism underlying GM-CSF-dependent priming is not understood, we investigated the effects of GM-CSF on the phosphorylation of the cytosolic NADPH oxidase components p47(phox) and p67(phox). Preincubation of neutrophils with GM-CSF alone increased the phosphorylation of p47(phox) but not that of p67(phox). Addition of formyl-methionyl-leucyl-phenylalanine (fMLP) to GM-CSF-pretreated neutrophils resulted in more intense phosphorylation of p47(phox) than with GM-CSF alone and fMLP alone. GM-CSF-induced p47(phox) phosphorylation was time- and concentration-dependent and ran parallel to the priming effect of GM-CSF on superoxide production. Two-dimensional tryptic peptide mapping of p47(phox) showed that GM-CSF induced phosphorylation of one major peptide. fMLP alone induced phosphorylation of several peptides, an effect enhanced by GM-CSF pretreatment. In contrast to fMLP and phorbol 12-myristate 13-acetate, GM-CSF-induced phosphorylation of p47(phox) was not inhibited by the protein kinase C inhibitor GF109203X. The protein-tyrosine kinase inhibitor genistein and the phosphatidylinositol 3-kinase inhibitor wortmannin inhibited the phosphorylation of p47(phox) induced by GM-CSF and by fMLP but not that induced by phorbol 12-myristate 13-acetate. GM-CSF alone did not induce p47(phox) or p67(phox) translocation to the membrane, but neutrophils treated consecutively with GM-CSF and fMLP showed an increase (compared with fMLP alone) in membrane translocation of p47(phox) and p67(phox). Taken together, these results show that the priming action of GM-CSF on the neutrophil respiratory burst involves partial phosphorylation of p47(phox) on specific serines and suggest the involvement of a priming pathway regulated by protein-tyrosine kinase and phosphatidylinositol 3-kinase.
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PMID:Priming of human neutrophil respiratory burst by granulocyte/macrophage colony-stimulating factor (GM-CSF) involves partial phosphorylation of p47(phox). 1040 Jul 4


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