Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.3.1 (NADPH oxidase)
 11,281 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Luminol chemiluminescence in phorbolester-activated cultured rat liver Kupffer cells was strongly inhibited by the selenoorganic compound ebselen (IC50 = 2 mumol/L). Ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]one) also diminished reduction of ferricytochrome c (IC50 = 10 mumol/L), indicating a suppression of superoxide anion formation. Likewise, in lipopolysaccharide-pretreated Kupffer cells, ebselen proved to be a potent inhibitor of the conversion of oxyhemoglobin to methemoglobin (IC50 = 3 mumol/L) as a measure of nitric oxide formation. The sulfur-containing analog (2-phenyl-1,2-benzisothiazol-3[2H]one) and the ebselen derivative, methylselenobenzanilide, were inactive. These results indicate that ebselen is a potent inhibitor of NADPH oxidase in Kupffer cells, as has been reported for other macrophages and granulocytes. In addition, they suggest a novel characteristic of ebselen, namely very effective inhibition of nitric oxide synthase of macrophages. In line with its inhibitory effects on the release of reactive oxygen species by macrophages, complemented by its antioxidant properties, ebselen was potent in the prevention of reoxygenation injury of Kupffer cells (IC50 approximately 5 mumol/L).
 ...
PMID:Inhibition of superoxide and nitric oxide release and protection from reoxygenation injury by Ebselen in rat Kupffer cells. 137 78

The origin of luminol-dependent chemiluminescence (CL) in neutrophils stimulated by immune complexes (IC) was investigated. It was found that CL induced by soluble IC and aggregated human gamma globulin (AHG) was glucose-independent, while insoluble IC-induced CL was diminished in the absence of glucose. AHG-induced CL was not inhibited by superoxide dismutase, catalase or 2,5-dimethyl furan, but was suppressed in the presence of phenol, sodium benzoate, sodium formate and mannitol. The CL was also inhibited by inhibitors of arachidonic acid (AA) metabolism including 5,8,11,14-eicosatetraynoic acid, nordihydroguaiaretic acid, quinacrine, indomethacin and aspirin, and by prostaglandins E1 and E2, theophylline and dibutyryl cyclic AMP. Luminol-dependent CL was also studied in cell-free systems including AA plus soybean lipoxygenase, hydroperoxyeicosatetraenoic acid plus peroxidase and xanthine oxidase plus xanthine. Our results indicate that, in neutrophils exposed to soluble IC and AHG, CL is produced and this is closely linked to the formation of free radicals during the metabolism of AA. The radical(s) involved is likely to include the hydroxyl radical. In neutrophils stimulated by large aggregates of IC or micro-organisms, superoxide anion, H2O2 and singlet oxygen are also produced as a result of activation of NAD(P)H oxidase. These oxygen species function as oxidizing agents for AA metabolism and amplify the production of hydroxyl radical along the lipoxygenase (and possibly cyclooxygenase) pathway(s).
 ...
PMID:Luminol-dependent chemiluminescence produced by neutrophils stimulated by immune complexes. 608 70

Luminol chemiluminescence induced by phagocytosis of bacteria was studied in a system consisting of polymorphonuclear granulocytes (PMN), serum, luminol and Staphylococcus aureus. To evaluate the quantitative relationship between luminol chemiluminescence and the bactericidal process time courses for both variables were compared. It was found that initial rate of increase of chemiluminescence and initial rate of killing of bacteria were well correlated whereas the correlation was poorer for later stages of the process. When the rate of the bactericidal process was varied by changing concentrations of bacteria and PMN, directly proportional variations of initial rates of increase of chemiluminescence were observed. This is interpreted as reflecting an accumulation of oxidizing radicals as the result of a phagocytosis dependent gradual activation of the NADPH oxidase system, leading to luminol oxidation and/or killing of bacteria. However, by thermal inactivation of PMNs, chemiluminescence could be diminished whereas killing remained essentially unaffected, showing that these two processes could be uncoupled. Also, addition of erythrocytes to the PMN suspension was associated with decreased chemiluminescence and lysis of erythrocytes with an increased chemiluminescence, emphasizing the importance of proper control of the components of the leucocyte test suspension.
 ...
PMID:The relationship between luminol chemiluminescence and killing of staphylococcus aureus by neutrophil granulocytes. 733 86

Based on our previous evidence indicating that the elevated sister chromatid exchange that characterizes Bloom syndrome (BS) cells may arise in response to elevated production of active oxygen, we have quantitated the levels of active oxygen in two control, two BS and one BS revertant cell lines. Luminol-dependent chemiluminescence was used as a measure of active oxygen production following treatment of the cells with the calcium ionophore A23187 or the chemotactic tripeptide N-formylmethionylleucylphenylalanine. A peptide factor present in plasma was required for priming the cells to undergo the oxidative response. As determined with A23187, active oxygen production was elevated in BS cell lines by 48.6% above control. Using N-formylmethionylleucylphenylalanine, active oxygen production was found to be increased by 250-314%. Chemiluminescence was inhibited in a dose-dependent manner by diphenylene iodonium, which specifically binds to and inhibits membrane-associated NADPH oxidase activity. This compound inhibited oxygen radical production nearly 3 times more effectively in control cells than in BS cells. The capacity to produce elevated levels of oxygen radicals may contribute to the spontaneous chromosomal instability of BS cells and to the associated high incidence of neoplasia in individuals with BS.
 ...
PMID:Elevated production of active oxygen in Bloom's syndrome cell lines. 822 45

Nitric oxide synthase (NOS) inhibitors have been reported to modulate luminol-dependent chemiluminescence (CL) in rat macrophages, whereas the potent oxidant peroxynitrite (ONOO-) was shown to react with luminol to yield CL in a cell-free system. We evaluated the role of the L-arginine/NOS pathway in luminol CL by phorbol ester-activated human polymorphonuclear (PMN) leukocytes using the NOS inhibitors NG-monomethyl-L-arginine (L-NMMA) and N-iminoethyl-L-ornithine (L-NIO). Nitric oxide (.NO) release was determined by oxidation of oxymyoglobin. In addition, the effect of NOS inhibitors on superoxide anion O2.-) production was measured. Luminol CL was notably diminished by L-NMMA in a dose-dependent manner. Superoxide dismutase (SOD) also decreased luminol CL and L-NMMA potentiated light emission decrease produced by SOD. Nitric oxide and O2.- production was significantly decreased by L-NMMA; moreover, luminol-dependent CL but not O2.- production was attenuated by L-NIO. These data suggest that products of catalytic activity of both .NO synthase and NADPH oxidase are required to elicit maximal luminol CL in this system. These studies demonstrate that the NOS synthase pathway is involved in luminol CL by human PMN, and they suggest that ONOO- would be an unrecognized mediator in this phenomenon.
 ...
PMID:Nitric oxide synthase inhibitors decrease human polymorphonuclear leukocyte luminol-dependent chemiluminescence. 858 46

Pyelonephritis is the most common urinary tract infection affecting females of all age groups. Despite concerted efforts the mechanism of renal injury in pyelonephritis is not clearly understood. In the present study we have made an attempt to characterise the mediators of inflammatory insult in an experimental model of ascending pyelonephritis. Mice infected with Escherichia coli O6:K13:H1 were sacrificed at 2, 7 and 14 days post-infection. Luminol-dependent chemiluminescence response, NADPH oxidase, acid phosphatase, beta-glucuronidase and N-acetyl-beta-D-glucosaminidase activities were monitored in circulating as well as renal phagocytic cells in order to determine the role of reactive oxygen species and lysosomal enzymes in genesis of renal injury. We have demonstrated that reactive oxygen species are generated at the initiation of infection and the levels increase progressively during the course of infection. While intracellular release of lysosomal enzymes was seen in all groups, extracellular release was primarily observed at 7 and 14 days post-infection only. The results indicate that while reactive oxygen species play a significant role in tissue injury during all stages of infection, lysosomal enzyme release in extracellular milieu augments tissue destruction at later stages only.
 ...
PMID:Oxygen-dependent and -independent mechanisms of renal injury in experimental ascending pyelonephritis. 882 96

A method was developed for testing the cytotoxicity of various bandage-like wound dressings and gel wound dressings. In this method, the ability of human polymorphonuclear neutrophils (PMNs) to initiate a respiratory burst after exposure to the various wound dressings is used as a marker of cytotoxicity. Luminol-amplified chemiluminescence stimulated with opsonised zymosan or phorbol 12-myristate 13-acetate (PMA) is used to measure the degree of activation of the respiratory burst, i.e. the NADPH oxidase activity, after exposure to wound dressings. Opsonised zymosan (material from yeast cell walls) is a phagocytic stimulus that activates the NADPH oxidase by binding to FC-receptors and complement receptors, and functions as an artificial bacterium, whereas PMA activates the NADPH oxidase by direct activation of protein kinase C. NADPH oxidase activity was inhibited by several wound dressings. The down-regulation of the respiratory burst is detrimental to the bactericial effect of PMNs, and can be used as a marker for the cytotoxicity of wound dressing materials.
 ...
PMID:Cytotoxicity testing of wound-dressing materials. 1138 24

Sepsis is associated with increased production of reactive oxygen species (ROS); however, the metabolic sources of increased ROS are not well understood. We hypothesized that the recently described nonphagocytic NAD(P)H oxidase system could be an important source of the ROS superoxide anion (O2-) during sepsis, and the interaction of O2- with nitric oxide (NO) may contribute to sepsis-induced vascular Injury. To evaluate this issue, we measured O2- production before and after treatment with lipopolysaccharide (LPS) in rats, who are Inducible NO synthase producers (NOSII) and in pigs, who do not produce NOSII. LPS increased O2- production in aorta from rats from 0.38 +/- 0.07 nmol/mg/10 min to 1.18 +/- 0.23 nmol/mg/10 min, (P = 0.001) in rats, and 0.63 +/- 0.05 nmol/mg/10 min to 1.5 +/- 1.6 nmol/mg/10 min (P = 0.001) in carotid arteries from pigs. Components of NAD(P)H oxidase, including p22(phox), gp91(phox), p47(phox), p67(phox), mRNA and p22(phox), and gp91(phox) proteins were present in rat aorta and aorta and carotid arteries from pigs. Expression mildly increased in rats, but not in pigs. In rats, NADH and NADPH greatly increased O2- production with no difference in untreated versus LPS-treated rats. The addition of L-NAME increased NADH-dependant O2- production from 75 +/- 3 nmol/O2-/mg/10 min to 113 +/- 7 nmoVO2-/mg/10 min in LPS-treated rats, but had no effect in untreated rats. In pigs, the NADH-stimulated O2- production was 43 +/- 8 nmol/mg/10 min before and 63 +/- 4.3 nmol/mg/10 min after LPS even without L-NAME (P < 0.05). In contrast to LPS-treated rats, L-NAME markedly decreased NADH-stimulated O2- production (63 +/- 4 nmol/mg/10 min to 33 +/- 5.6 nmol/mg/10 min, P < 0.01). Luminol-enhanced chemiluminescence was also Increased in porcine carotid arteries after LPS treatment, which is consistent with peroxynitrite formation. Our results indicate that components of NAD(P)H oxidase are present in vessels of pigs and rats and there is substantial NADH-dependent O2- production that is increased after LPS. However, the behavior of NAD(P)H oxidase in NOSII-producing and nonproducing species differs with a reduction of O2- by NO in rats and NO-dependent production in pigs.
 ...
PMID:Superoxide production in the vasculature of lipopolysaccharide-treated rats and pigs. 1274 95

Inflammation is a fundamental aspect of many human diseases. In this video report, we demonstrate non-invasive bioluminescence imaging techniques that distinguish acute and chronic inflammation in mouse models. With tissue damage or pathogen invasion, neutrophils are the first line of defense, playing a major role in mediating the acute inflammatory response. As the inflammatory reaction progresses, circulating monocytes gradually migrate into the site of injury and differentiate into mature macrophages, which mediate chronic inflammation and promote tissue repair by removing tissue debris and producing anti-inflammatory cytokines. Intraperitoneal injection of luminol (5-amino-2,3-dihydro-1,4-phthalazinedione, sodium salt) enables detection of acute inflammation largely mediated by tissue-infiltrating neutrophils. Luminol specifically reacts with the superoxide generated within the phagosomes of neutrophils since bioluminescence results from a myeloperoxidase (MPO) mediated reaction. Lucigenin (bis-N-methylacridinium nitrate) also reacts with superoxide in order to generate bioluminescence. However, lucigenin bioluminescence is independent of MPO and it solely relies on phagocyte NADPH oxidase (Phox) in macrophages during chronic inflammation. Together, luminol and lucigenin allow non-invasive visualization and longitudinal assessment of different phagocyte populations across both acute and chronic inflammatory phases. Given the important role of inflammation in a variety of human diseases, we believe this non-invasive imaging method can help investigate the differential roles of neutrophils and macrophages in a variety of pathological conditions.
 ...
PMID:In vivo imaging method to distinguish acute and chronic inflammation. 2397 51