Diphenyleneiodonium inhibits both potassium and calcium currents in isolated pulmonary artery smooth muscle cells

Weir, Ε. Kenneth; Wyatt, Christopher N.; Reeve, Helen L.; Huang, Jianhe; Archer, SL; Peers, Chris

doi:10.1152/jappl.1994.76.6.2611

Cited by 71 publications

(47 citation statements)

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“…Moreover, experimental evidence suggests that the action of DPI and other iodonium-containing compounds is not restricted to flavoenzymes only. Indeed, DPI caused reversible blockade of K ϩ and Ca 2ϩ currents in isolated type I carotid body cells (12) and in pulmonary smooth muscle cells (13), indicating that DPI is a nonselective ion channel blocker. Both DPI and DIP have been found to be antagonists of the Nmethyl-D-aspartate receptors, through inhibition of opening processes of the ion channel (14); by this way, DIP protects neurons against glutamate toxicity (15).…”

Section: From the Department Of Genetics Biology And Biochemistry mentioning

confidence: 98%

Diphenyleneiodonium Inhibits the Cell Redox Metabolism and Induces Oxidative Stress

Riganti

Gazzano

Polimeni

et al. 2004

Journal of Biological Chemistry

179

133

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Diphenyleneiodonium (DPI) and the structurally related compound diphenyliodonium (DIP) are widely used as inhibitors of flavoenzymes, particularly NADPH oxidase. Here we report further evidence that DPI and DIP are not specific flavin binders. A 3-h incubation of N11 glial cells with DPI significantly inhibited in a dosedependent way both the pentose phosphate pathway and the tricarboxylic acid cycle. In parallel, we observed a dose-dependent increase of reactive oxygen species generation and lipoperoxidation and increased leakage of lactate dehydrogenase activity in the extracellular medium. The glutathione/glutathione disulfide ratio decreased, whereas the efflux of glutathione out of the cells increased. This suggests that DPI causes an augmented oxidative stress and exerts a cytotoxic effect in N11 cells. Indeed, the cells were protected from these events when loaded with glutathione. Similar results were observed using DIP instead of DPI and also in other cell types. We suggest that the DPI-elicited inhibition of the pentose phosphate pathway and tricarboxylic acid cycle may be mediated by the blockade of several NAD(P)-dependent enzymes, such as glucose 6-phosphate dehydrogenase, glyceraldehyde 3-phosphate dehydrogenase, and lactate dehydrogenase. In light of these results, we think that some effects of DPI or DIP in in vitro and in vivo experimental models should be interpreted with caution. Diphenyleneiodonium (DPI) 1 and the structurally related compound diphenyliodonium (DIP) are widely used as uncompetitive inhibitors of flavoenzymes. Firstly identified as a hypoglycemic agent able to block gluconeogenesis and respiration in rat liver (1), DPI has been subsequently shown to inhibit the activity of NADH:ubiquinone oxidoreductase (2, 3), NADPH oxidase (4 -6), nitric-oxide synthase (7), xanthine oxidase (6), and NADPH cytochrome P450 oxidoreductase (8). DPI and other iodonium derivatives have been shown to react via a radical mechanism, whereby an electron is abstracted from FAD or FMN to form a radical, which then adds back to the flavin to form covalent, phenylated adducts (9). Also, heme groups, such as the heme b of NADPH oxidase, have been found to react with DPI and DIP (10).In most experimental works of the last years, DPI or DIP have been used as inhibitors of NADPH oxidase. NADPH oxidases are a group of plasma membrane-associated enzymes found in a variety of cells of mesodermal origin. The most thoroughly studied is the leukocyte isoform, which catalyzes the production of superoxide (O 2 . ) by the one-electron reduction of oxygen, using NADPH as the reducing agent (11). The O 2 .generated by NADPH oxidase serves as the starting material for the production of a vast assortment of reactive oxidants used by phagocytes to kill invading microorganisms or tumor cells (11). A low activity NADPH oxidase is present in a variety of nonphagocytic cells, wherein this enzyme is a source of second messengers. It has been postulated, for instance, that the O 2 . generated by the aorta functions as a blood ...

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Section: From the Department Of Genetics Biology And Biochemistry mentioning

confidence: 98%

Diphenyleneiodonium Inhibits the Cell Redox Metabolism and Induces Oxidative Stress

Riganti

Gazzano

Polimeni

et al. 2004

Journal of Biological Chemistry

179

133

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“…Moreover, a number of publications show that Nox inhibition by DPI, iodonium diphenyl, and aminoethylbenzenesulfonyl fluoride all reduce the acute hypoxiainduced increase in [Ca 2þ ] i and contraction in cultured rat PASMCs (118), and vasoconstriction in isolated calf pulmonary arteries (52) and in rabbit and rat lungs (22, 88, 110). However, the specificity of iodonium compounds as Nox inhibitors has been disputed, because these agents can inhibit the mitochondrial ETC in heart cells and voltage-dependent Ca 2þ currents in PASMCs (68,107). Whereas gp91 phox-=-mice show normal or reduced acute hypoxic responses (6,42,44), acute hypoxic vasoconstriction is inhibited in p47 phox-=-mice (112).…”

Section: Nadph Oxidase Is Involved In the Hypoxic Increase In [Ros] Imentioning

confidence: 99%

ROS-Dependent Signaling Mechanisms for Hypoxic Ca²⁺Responses in Pulmonary Artery Myocytes

Wang

Zheng

2010

Antioxidants & Redox Signaling

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Hypoxic exposure causes pulmonary vasoconstriction, which serves as a critical physiologic process that ensures regional alveolar ventilation and pulmonary perfusion in the lungs, but may become an essential pathologic factor leading to pulmonary hypertension. Although the molecular mechanisms underlying hypoxic pulmonary vasoconstriction and associated pulmonary hypertension are uncertain, increasing evidence indicates that hypoxia can result in a significant increase in intracellular reactive oxygen species concentration ([ROS] i ) through the mitochondrial electron-transport chain in pulmonary artery smooth muscle cells (PASMCs). The increased mitochondrial ROS subsequently activate protein kinase C-e (PKCe) and NADPH oxidase (Nox), providing positive mechanisms that further increase [ROS]

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“…Ahluwalia (2) has indicated that Cl Ϫ current activated by cell swelling in human neutrophiles counteracts a depolarization induced by the NADPH oxidase. Furthermore, DPI has been reported to inhibit K ϩ channels in, e.g., isolated pulmonary smooth muscle cells (74) and type I cells from neonatal rat carotid body (76). To test whether inhibition of the volumesensitive K ϩ and Cl Ϫ channels would have an impact on the ROS production following hypotonic exposure, we estimated the change in fluorescence with time in NIH3T3 cells after hypotonic exposure in the absence and presence of tamoxifen and clofilium, which are recognized as potent blockers of the volume-sensitive Cl Ϫ and K ϩ channels, respectively (33,58).…”

Section: Catalytic and Regulatory Nadph Oxidase Subunits Expressed Inmentioning

confidence: 99%

Volume-sensitive NADPH oxidase activity and taurine efflux in NIH3T3 mouse fibroblasts

Friis

Vorum²,

Lambert

2008

American Journal of Physiology-Cell Physiology

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Friis MB, Vorum KG, Lambert IH. Volume-sensitive NADPH oxidase activity and taurine efflux in NIH3T3 mouse fibroblasts. Am J Physiol Cell Physiol 294: C1552-C1565, 2008. First published April 16, 2008 doi:10.1152/ajpcell.00571.2007.-Reactive oxygen species (ROS) are produced in NIH3T3 fibroblasts during hypotonic stress, and H2O2 potentiates the concomitant release of the organic osmolyte taurine (Lambert IH. J Membr Biol 192: 19 -32, 2003). The increase in ROS production [5-(and-6)-carboxy-2Ј, 7Ј-dichlorodihydrofluorescein diacetate fluorescence] is detectable after a reduction in the extracellular osmolarity from 335 mosM (isotonic) to 300 mosM and reaches a maximal value after a reduction to 260 mosM. The swelling-induced ROS production is reduced by the flavoprotein inhibitor diphenylene iodonium chloride (25 M) but is unaffected by the nitric oxide synthase inhibitor N -nitro-L-arginine methyl ester, indicating that the volume-sensitive ROS production is NADPH oxidase dependent. NIH3T3 cells express the NADPH oxidase components: p22 phox , a NOX4 isotype; p47 phox ; and p67 phox (real-time PCR). Exposure to the Ca 2ϩ -mobilizing agonist ATP (10 M) potentiates the release of taurine but has no effect on ROS production under hypotonic conditions. On the other hand, addition of the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA, 100 nM) or the lipid messenger lysophosphatidic acid (LPA, 10 nM) potentiates the swelling-induced taurine release as well as the ROS production. Overexpression of Rac1 or p47 phox or p47 phox knockdown [small interfering (si)RNA] had no effect on the swelling-induced ROS production or taurine release. NOX4 knockdown (siRNA) impairs the increase in the ROS production and the concomitant taurine release following osmotic exposure. It is suggested that a NOX4 isotype plus p22 phox account for the swelling-induced increase in the ROS production in NIH3T3 cells and that the oxidase activity is potentiated by PKC and LPA but not by Ca 2ϩ . organic osmolytes; NOX4; lysophospholipids; arachidonic acid mobilization; adenosine triphosphate; calcium REACTIVE OXYGEN SPECIES (ROS), e.g., superoxides, hydroxyl radicals, and H 2 O 2 , are produced in a variety of cells upon ligand stimulation, during stress, cell proliferation, and apoptosis (9,16,59,62,63). Within recent years, it has been shown that ROS are produced also upon osmotic stress in various cell types (35,51,71) and that ROS are involved in the swellinginduced activation and inactivation of the volume-sensitive release pathway for the organic osmolyte taurine in, e.g., NIH3T3 fibroblasts (35, 38) and in the activity of the volumesensitive, outwardly rectifying Cl Ϫ channel in liver cells (71). Activation of the volume-sensitive taurine release pathway in NIH3T3 fibroblasts involves specific phospholipase A 2 (PLA 2 ) (40,41), and it appears that the swelling-induced ROS production involves a NADPH oxidase, which is activated at a step downstream to the PLA 2 activation (35). Colston and coworkers (13) similarly ...

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Diphenyleneiodonium inhibits both potassium and calcium currents in isolated pulmonary artery smooth muscle cells

Cited by 71 publications

References 0 publications

Diphenyleneiodonium Inhibits the Cell Redox Metabolism and Induces Oxidative Stress

Diphenyleneiodonium Inhibits the Cell Redox Metabolism and Induces Oxidative Stress

ROS-Dependent Signaling Mechanisms for Hypoxic Ca²⁺Responses in Pulmonary Artery Myocytes

Volume-sensitive NADPH oxidase activity and taurine efflux in NIH3T3 mouse fibroblasts

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Diphenyleneiodonium inhibits both potassium and calcium currents in isolated pulmonary artery smooth muscle cells

Cited by 71 publications

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Diphenyleneiodonium Inhibits the Cell Redox Metabolism and Induces Oxidative Stress

Diphenyleneiodonium Inhibits the Cell Redox Metabolism and Induces Oxidative Stress

ROS-Dependent Signaling Mechanisms for Hypoxic Ca2+Responses in Pulmonary Artery Myocytes

Volume-sensitive NADPH oxidase activity and taurine efflux in NIH3T3 mouse fibroblasts

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ROS-Dependent Signaling Mechanisms for Hypoxic Ca²⁺Responses in Pulmonary Artery Myocytes