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

---

Query: EC:1.6.99.6 (NADPH oxidase)
10,295 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The elicitation of an oxidative burst in phagocytes rests on the assembly of a multicomponental complex (NADPH oxidase) consisting of a membrane-associated flavocytochrome (cytochrome b559), representing the redox element responsible for the NADPH-dependent reduction of oxygen to superoxide (O-2), two cytosolic components (p47(phox), p67(phox)), and the small GTPase Rac (1 or 2). We found that 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), an irreversible serine protease inhibitor, prevented the elicitation of O-2 production in intact macrophages and the amphiphile-dependent activation of NADPH oxidase in a cell-free system, consisting of solubilized membrane or purified cytochrome b559 combined with total cytosol or a mixture of recombinant p47(phox), p67(phox), and Rac1. AEBSF acted at the activation step and did not interfere with the ensuing electron flow. It did not scavenge oxygen radicals and did not affect assay reagents. Five other serine protease inhibitors (three irreversible and two reversible) were found to lack an inhibitory effect on cell-free activation of NADPH oxidase. A structure-function study of AEBSF analogues demonstrated that the presence of a sulfonyl fluoride group was essential for inhibitory activity and that compounds containing an aminoalkylbenzene moiety were more active than amidinobenzene derivatives. Exposure of the membrane fraction or of purified cytochrome b559, but not of cytosol or recombinant cytosolic components, to AEBSF, in the presence of a critical concentration of the activating amphiphile lithium dodecyl sulfate, resulted in a marked impairment of their ability to support cell-free NADPH oxidase activation upon complementation with untreated cytosol or cytosolic components. Kinetic analysis of the effect of varying the concentration of each of the three cytosolic components on the inhibitory potency of AEBSF indicated that this was inversely related to the concentrations of p47(phox) and, to a lesser degree, p67(phox). AEBSF also prevented the amphiphile-elicited translocation of p47(phox) and p67(phox) to the membrane. These results are interpreted as indicating that AEBSF interferes with the binding of p47(phox) and/or p67(phox) to cytochrome b559, probably by a direct effect on cytochrome b559.
...
PMID:Inhibition of NADPH oxidase activation by 4-(2-aminoethyl)-benzenesulfonyl fluoride and related compounds. 914 50

Hypoxic pulmonary vasoconstriction (HPV) matches lung perfusion with ventilation. Controversy exists whether decreased or increased reactive oxygen species may elicit HPV and from which source such oxygen metabolites are derived. In rabbit lungs, we detected transcripts of a nonphagocytic NADPH oxidase subunit homologous to mitogenic oxidase-1 (Mox1) or NADPH oxidase homolog 1 (NOH-1L). In perfused rabbit lungs, we employed 1) a new NADPH oxidase inhibitor [4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF; 100-600 microM)] and 2) the superoxide dismutase (SOD) inhibitors diethyldithiocarbamic acid (DETC; 100 microM to 10 mM) and triethylenetetramine (TETA; 1-25 mM). Specificity of these agents for HPV was investigated by comparison with U-46619-induced vasoconstrictions. AEBSF induced a transient increase in pulmonary arterial pressure with increased strength of HPV. Subsequent to this initial response, normoxic pulmonary arterial pressure was not affected and HPV was specifically suppressed. Whereas DETC turned out to act in a nonspecific fashion, TETA suppressed HPV specifically. These findings provide evidence of a role for a nonphagocytic NAD(P)H oxidase with superoxide and SOD-related hydrogen peroxide formation in HPV. Because HPV was inhibited but not mimicked by the inhibitors, increased rather than decreased superoxide and/or hydrogen peroxide formation is suggested as the hypoxia-provoked signaling event.
...
PMID:Hypoxic vasoconstriction in intact lungs: a role for NADPH oxidase-derived H(2)O(2)? 1100 Jan 28

We investigated the mechanism of cell toxicity of alpha-tocopheryl hemisuccinate (TS). TS concentration- and time-dependently induced the lactate dehydrogenase release and DNA fragmentation of rat vascular smooth muscle cells (VSMC). Exogenous addition of superoxide dismutase, but not catalase, significantly inhibited the cell toxicity of TS. The NADPH-dependent oxidase activity of VSMC was stimulated by TS treatment. The cell toxicity of TS was inhibited by NADPH oxidase inhibitor 4-(2-aminoethyl)-benzenesulfonyl fluoride. Consequently, TS-induced apoptosis of VSMC was suggested to be caused by exogenous O(2)(-) generated via the oxidase system activated with TS.
...
PMID:Superoxide is responsible for apoptosis in rat vascular smooth muscle cells induced by alpha-tocopheryl hemisuccinate. 1151 94

Vascular endothelial growth factor (VEGF) is a potent vascular endothelial cell-specific mitogen that modulates endothelial cell function. In the present study, we show that VEGF induces manganese-superoxide dismutase (MnSOD) mRNA and protein in human coronary artery endothelial cells (HCAEC) and pulmonary artery endothelial cells. VEGF-mediated induction of MnSOD mRNA was inhibited by pretreatment with the NADPH oxidase inhibitors, diphenyleneiodonium (DPI), and 4-(2-aminoethyl)-benzenesulfonyl fluoride, but not with the nitric oxide synthase inhibitor L-NAME (N-monomethyl-L-arginine) or the xanthine oxidase inhibitor allopurinol. VEGF stimulation of MnSOD was also inhibited by adenoviral-mediated overexpression of catalase Cu, Zn-SOD and a dominant-negative form of the small GTPase component of NADPH oxidase Rac1 (Rac1N17). Treatment of HCAEC with VEGF resulted in a transient increase in ROS production at 20 min, as measured by 2,7-dichlorodihydrofluorescein oxidation. This effect was abrogated by expression of Rac1N17. Taken together, these findings suggest that VEGF induces MnSOD by an NADPH oxidase-dependent mechanism and that VEGF signaling in the endothelium is coupled to the redox state of the cell.
...
PMID:Vascular endothelial growth factor induces manganese-superoxide dismutase expression in endothelial cells by a Rac1-regulated NADPH oxidase-dependent mechanism. 1164 Dec 65

A significant increase in the induction of inducible nitric-oxide synthase (iNOS) protein expression and in the levels of nitrite plus nitrate was observed in rat aortic smooth muscle cells (RASMCs) stably transfected with catalase (RASMC-2C2) as compared with empty vector-transfected RASMC-V4 cells after exposure to cytokines and lipopolysaccharide. The increased expression of iNOS protein in the RASMC-2C2 cells was associated with a significant activation of nuclear transcription factor kappaB, one of the transcriptional regulators of iNOS expression. The induction of iNOS was also accompanied by increased protein tyrosine nitration in both cell types as revealed by immunocytochemical staining and high pressure liquid chromatography with on-line electrospray ionization tandem mass spectrometry. Nitrotyrosine formation was inhibited by 1400W, an iNOS inhibitor, by 4-(2-aminoethyl) benzenesulfonyl fluoride, an inhibitor of NADPH oxidase, and by the superoxide dismutase mimetic M40403, but not by the peroxidase inhibitor 4-aminobenzoic hydrazide. Electron microscopy using affinity-purified anti-nitrotyrosine antibodies revealed labeling at the cytosolic side of the rough endoplasmic reticulum membranes, in the nucleus, occasionally in mitochondria, and consistently within the fibrillar layer underneath the plasma membrane. Collectively, the data in this model system indicate that hydrogen peroxide, by inhibiting the activation of nuclear transcription factor kappaB, prevents iNOS expression, whereas superoxide contributes in a precise pattern of intracellular protein tyrosine nitration.
...
PMID:Expression of inducible nitric-oxide synthase and intracellular protein tyrosine nitration in vascular smooth muscle cells: role of reactive oxygen species. 1269 Jan 3

The purpose of this study was to determine the role of NADPH oxidase in H(+) secretion by airway epithelia. In whole cell patch clamp recordings primary human tracheal epithelial cells (hTE) and the human serous gland cell line Calu-3 expressed a functionally similar zinc-blockable plasma membrane H(+) conductance. However, the rate of H(+) secretion of confluent epithelial monolayers measured in Ussing chambers was 9-fold larger in hTE compared with Calu-3. In hTE H(+) secretion was blocked by mucosal ZnCl(2) and the NADPH oxidase blockers acetovanillone and 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF), whereas these same blockers had no effect in Calu-3. We determined levels of transcripts for the NADPH oxidase transmembrane isoforms (Nox1 through -5, Duox1 and -2, and p22(phox)) and found Duox1, -2, and p22(phox) to be highly expressed in hTE, as well as the intracellular subunits p40(phox), p47(phox), and p67(phox). In contrast, Calu-3 lacked transcripts for Duox1, p40(phox), and p47(phox). Anti-Duox antibody staining resulted in prominent apical staining in hTE but no significant staining in Calu-3. When treated with amiloride to block the Na(+)/H(+) exchanger, intracellular pH in hTE acidified at significantly higher rates than in Calu-3, and treatment with AEBSF blocked acidification. These data suggest a role for an apically located Duox-based NADPH oxidase during intracellular H(+) production and H(+) secretion, but not in H(+) conduction.
...
PMID:NADPH oxidase-dependent acid production in airway epithelial cells. 1521 Jun 97

Although reactive oxygen species (ROS) participate in many cellular mechanisms, only few data exist concerning their involvement in physiological angiogenesis. The aim of the present work was to elucidate possible mechanisms through which ROS affect angiogenesis in vivo, using the model of the chicken embryo chorioallantoic membrane (CAM). Superoxide dismutase (SOD) and its membrane permeable mimetic tempol, dose dependently decreased angiogenesis and down-regulated inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production. The NADPH oxidase inhibitors, 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF) and apocynin, but not allopurinol, also had a dose dependent inhibitory effect on angiogenesis and NO production in vivo. Catalase and the intracellular hydrogen peroxide (H2O2) scavenger sodium pyruvate decreased, while H2O2 increased in a dose-dependent manner the number of CAM blood vessels, as well as the expression and activity of iNOS. Dexamethasone, which down-regulated NO production by iNOS and L-NAME, but not D-NAME, dose dependently decreased angiogenesis in vivo. These data suggest that antioxidants affect physiological angiogenesis in vivo, through regulation of NOS expression and activity.
...
PMID:Antioxidants inhibit angiogenesis in vivo through down-regulation of nitric oxide synthase expression and activity. 1529 58

Direct stretch of beta1 integrin activates an outwardly rectifying, tamoxifen-sensitive Cl(-) current (Cl(-) SAC) via focal adhesion kinase (FAK) and/or Src. The characteristics of Cl(-) SAC resemble those of the volume-sensitive Cl(-) current, I(Cl,swell). Because myocyte stretch releases angiotensin II (AngII), which binds AT1 receptors (AT1R) and stimulates FAK and Src in an autocrine-paracrine loop, we tested whether AT1R and their downstream signaling cascade participate in mechanotransduction. Paramagnetic beads coated with mAb for beta1-integrin were applied to myocytes and pulled upward with an electromagnet while recording whole-cell anion current. Losartan (5 microM), an AT1R competitive antagonist, blocked Cl(-) SAC but did not significantly alter the background Cl(-) current in the absence of integrin stretch. AT1R signaling is mediated largely by H(2)O(2) produced from superoxide generated by sarcolemmal NADPH oxidase. Diphenyleneiodonium (DPI, 60 microM), a potent NADPH oxidase inhibitor, rapidly and completely blocked both Cl(-) SAC elicited by stretch and the background Cl(-) current. A structurally unrelated NADPH oxidase inhibitor, 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF, 0.5 and 2 mM), also rapidly and completely blocked Cl(-) SAC as well as a large fraction of the background Cl(-) current. With continuing integrin stretch, Cl(-) SAC recovered upon washout of AEBSF (2 mM). In the absence of stretch, exogenous AngII (5 nM) activated an outwardly rectifying Cl(-) current that was rapidly and completely blocked by DPI (60 microM). Moreover, exogenous H(2)O(2) (10, 100, and 500 microM), the eventual product of NADPH oxidase activity, also activated Cl(-) SAC in the absence of stretch, whereas catalase (1,000 U/ml), an H(2)O(2) scavenger, attenuated the response to stretch. Application of H(2)O(2) during NADPH oxidase inhibition by either DPI (60 microM) or AEBSF (0.5 mM) did not fully reactivate Cl(-) SAC, however. These results suggest that stretch of beta1-integrin in cardiac myocytes elicits Cl(-) SAC by activating AT1R and NADPH oxidase and, thereby, producing reactive oxygen species. In addition, NADPH oxidase may be intimately coupled to the channel responsible for Cl(-) SAC, providing a second regulatory pathway.
...
PMID:Angiotensin II (AT1) receptors and NADPH oxidase regulate Cl- current elicited by beta1 integrin stretch in rabbit ventricular myocytes. 1533 22

We have recently shown that superoxide and hydrogen peroxide are putative inducers of angiogenesis in vivo, possibly through up regulation of inducible nitric oxide synthase (NOS) and increased production of endogenous nitric oxide (NO). The aim of the present work was to elucidate the implication of reactive oxygen species in endothelial cell functions, using cultures of human umbilical vein endothelial cells (HUVEC). Superoxide dismutase (SOD), tempol (membrane permeable SOD mimetic) and the NADPH oxidase inhibitors, 4-(2-aminoethyl)-benzenesulfonyl fluoride and apocynin, but not allopurinol, inhibited HUVEC proliferation and migration, as well as activity of endothelial NOS (eNOS). Catalase and the intracellular hydrogen peroxide scavenger sodium pyruvate decreased, while hydrogen peroxide increased HUVEC proliferation, migration and activity of eNOS. Dexamethasone induced the proliferation and migration of HUVEC and activated eNOS. Nomega-nitro-L-arginine methyl ester (L-NAME), but not Nomega-nitro-D-arginine methyl ester, decreased endothelial cell functions and reversed the effects of dexamethasone and hydrogen peroxide. N5-(1-iminoethyl)-L-ornithine dihydrochloride, but not the inducible NOS specific inhibitor N-[[3-(aminomethyl)phenyl]methyl]-ethanimidamide dihydrochloride also decreased endothelial cell functions, similarly to L-NAME. The guanylate cyclase inhibitor 1H-[1,2,4]Oxadiazole[4,3-a]quinoxalin-1-one inhibited HUVEC proliferation in a concentration-dependent manner and completely reversed hydrogen peroxide-induced proliferation, migration and cGMP accumulation. In conclusion, superoxide and hydrogen peroxide seem to play a significant role in promoting endothelial cell proliferation and migration, possibly through regulation of eNOS activity.
...
PMID:Antioxidants inhibit human endothelial cell functions through down-regulation of endothelial nitric oxide synthase activity. 1574 Jul 22

Membrane potential in oxygen-sensitive type I cells in carotid body is controlled by diverse sets of voltage-dependent and -independent K(+) channels. Coupling of Po(2) to the open-closed state of channels may involve production of reactive oxygen species (ROS) by NADPH oxidase. One hypothesis suggests that ROS are produced in proportion to the prevailing Po(2) and a subset of K(+) channels closes as ROS levels decrease. We evaluated ROS levels in normal and p47(phox) gene-deleted [NADPH oxidase knockout (KO)] type I cells using the ROS-sensitive dye dihydroethidium (DHE). In normal cells, hypoxia elicited an increase in ROS, which was blocked by the specific NADPH oxidase inhibitor 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF, 3 mM). KO type I cells did not respond to hypoxia, but the mitochondrial uncoupler azide (5 microM) elicited increased fluorescence in both normal and KO cells. Hypoxia had no effect on ROS production in sensory and sympathetic neurons. Methodological control experiments showed that stimulation of neutrophils with a cocktail containing the chemotactic peptide N-formyl-Met-Leu-Phe (1 microM), arachidonic acid (10 microM), and cytochalasin B (5 microg/ml) elicited a rapid increase in DHE fluorescence. This response was blocked by the NADPH oxidase inhibitor diphenyleneiodonium (10 microM). KO neutrophils did not respond; however, azide (5 microM) elicited a rapid increase in fluorescence. Physiological studies in type I cells demonstrated that hypoxia evoked an enhanced depression of K+ current and increased intracellular Ca2+ levels in KO vs. normal cells. Moreover, AEBSF potentiated hypoxia-induced increases in intracellular Ca2+ and enhanced the depression of K+ current in low O(2). Our findings suggest that local compartmental increases in oxidase activity and ROS production inhibit the activity of type I cells by facilitating K+ channel activity in hypoxia.
...
PMID:Effect of p47phox gene deletion on ROS production and oxygen sensing in mouse carotid body chemoreceptor cells. 1628 Apr 59


1 2 Next >>

---