Inducible nitric oxide synthase augments injury elicited by oxidative stress in rat cardiac myocytes

1998 ◽  
Vol 274 (1) ◽  
pp. C245-C252 ◽  
Author(s):  
Junsuke Igarashi ◽  
Masashi Nishida ◽  
Shiro Hoshida ◽  
Nobushige Yamashita ◽  
Hiroaki Kosaka ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Cardiac Myocytes ◽  
Myocardial Injury ◽  
No Production ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
No Donor ◽  
Oxide Synthase ◽  
Gpx Activity

The effects of nitric oxide (NO) produced by cardiac inducible NO synthase (iNOS) on myocardial injury after oxidative stress were examined. Interleukin-1β induced cultured rat neonatal cardiac myocytes to express iNOS. After induction of iNOS,l-arginine enhanced NO production in a concentration-dependent manner. Glutathione peroxidase (GPX) activity in myocytes was attenuated by elevated iNOS activity and by an NO donor, S-nitroso- N-acetyl-penicillamine (SNAP). Although NO production by iNOS did not induce myocardial injury, NO augmented release of lactate dehydrogenase from myocyte cultures after addition of H2O2(0.1 mM, 1 h). Inhibition of iNOS with Nω-nitro-l-arginine methyl ester ameliorated the effects of NO-enhancing treatments on myocardial injury and GPX activity. SNAP augmented the myocardial injury induced by H2O2. Inhibition of GPX activity with antisense oligodeoxyribonucleotide for GPX mRNA increased myocardial injury by H2O2. Results suggest that the induction of cardiac iNOS promotes myocardial injury due to oxidative stress via inactivation of the intrinsic antioxidant enzyme, GPX.

Expression, localization, and regulation of NOS in human mast cell lines: effects on leukotriene production

Blood ◽  
2004 ◽  
Vol 104 (2) ◽  
pp. 462-469 ◽  
Author(s):  
Mark Gilchrist ◽  
Scott D. McCauley ◽  
A. Dean Befus
Keyword(s):  
Nitric Oxide ◽  
Protein Localization ◽  
Human Mast Cell ◽  
No Production ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
No Donor ◽  
No Formation ◽  
Health And Disease ◽  
Oxide Synthase

Abstract Nitric oxide (NO) is a potent radical produced by nitric oxide synthase (NOS) and has pleiotrophic activities in health and disease. As mast cells (MCs) play a central role in both homeostasis and pathology, we investigated NOS expression and NO production in human MC populations. Endothelial NOS (eNOS) was ubiquitously expressed in both human MC lines and skin-derived MCs, while neuronal NOS (nNOS) was variably expressed in the MC populations studied. The inducible (iNOS) isoform was not detected in human MCs. Both growth factor-independent (HMC-1) and -dependent (LAD 2) MC lines showed predominant nuclear eNOS protein localization, with weaker cytoplasmic expression. nNOS showed exclusive cytoplasmic localization in HMC-1. Activation with Ca2+ ionophore (A23187) or IgE-anti-IgE induced eNOS phosphorylation and translocation to the nucleus and nuclear and cytoplasmic NO formation. eNOS colocalizes with the leukotriene (LT)-initiating enzyme 5-lipoxygenase (5-LO) in the MC nucleus. The NO donor, S-nitrosoglutathione (SNOG), inhibited, whereas the NOS inhibitor, NG-nitro-l-arginine methyl ester (L-NAME), potentiated LT release in a dose-dependent manner. Thus, human MC lines produce NO in both cytoplasmic and nuclear compartments, and endogenously produced NO can regulate LT production by MCs. (Blood. 2004;104: 462-469)

scholarly journals Nitric Oxide Inhibits the Replication Cycle of Severe Acute Respiratory Syndrome Coronavirus

2005 ◽  
Vol 79 (3) ◽  
pp. 1966-1969 ◽  
Author(s):  
Sara Åkerström ◽  
Mehrdad Mousavi-Jazi ◽  
Jonas Klingström ◽  
Mikael Leijon ◽  
Åke Lundkvist ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Severe Acute Respiratory Syndrome ◽  
Inhibitory Effect ◽  
Replication Cycle ◽  
Dependent Manner ◽  
Virus Infections ◽  
Concentration Dependent Manner ◽  
No Donor ◽  
Oxide Synthase

ABSTRACT Nitric oxide (NO) is an important signaling molecule between cells which has been shown to have an inhibitory effect on some virus infections. The purpose of this study was to examine whether NO inhibits the replication cycle of the severe acute respiratory syndrome coronavirus (SARS CoV) in vitro. We found that an organic NO donor, S-nitroso-N-acetylpenicillamine, significantly inhibited the replication cycle of SARS CoV in a concentration-dependent manner. We also show here that NO inhibits viral protein and RNA synthesis. Furthermore, we demonstrate that NO generated by inducible nitric oxide synthase, an enzyme that produces NO, inhibits the SARS CoV replication cycle.

scholarly journals Nitric oxide can acutely modulate its biosynthesis through a negative feedback mechanism on l-arginine transport in cardiac myocytes

2010 ◽  
Vol 299 (2) ◽  
pp. C230-C239 ◽  
Author(s):  
Jiaguo Zhou ◽  
David D. Kim ◽  
R. Daniel Peluffo
Keyword(s):  
Nitric Oxide ◽  
Amino Acid ◽  
Cardiac Myocytes ◽  
Amino Acid Transporters ◽  
No Production ◽  
Cardiac Muscle Cells ◽  
No Donor ◽  
Rat Cardiomyocytes ◽  
Cationic Amino Acid ◽  
Intervention Point

Nitric oxide (NO) plays a central role as a cellular signaling molecule in health and disease. In the heart, NO decreases the rate of spontaneous beating and the velocity and extent of shortening and accelerates the velocity of relengthening. Since the cationic amino acid l-arginine (l-Arg) is the substrate for NO production by NO synthases (NOS), we tested whether the transporters that mediate l-Arg import in cardiac muscle cells represent an intervention point in the regulation of NO synthesis. Electrical currents activated by l-Arg with low apparent affinity in whole cell voltage-clamped rat cardiomyocytes were found to be rapidly and reversibly inhibited by NO donors. Radiotracer uptake studies performed on cardiac sarcolemmal vesicles revealed the presence of high-affinity/low-capacity and low-affinity/high-capacity components of cationic amino acid transport that were inhibited by the NO donor S-nitroso- N-acetyl-dl-penicillamine. NO inhibited uptake in a noncompetitive manner with Ki values of 275 and 827 nM for the high- and low-affinity component, respectively. Fluorescence spectroscopy experiments showed that millimolar concentrations of l-Arg initially promoted and then inhibited the release of endogenous NO in cardiomyocytes. Likewise, l-Arg currents measured in cardiac myocytes voltage clamped in the presence of 460 nM free intracellular Ca2+, a condition in which a Ca-CaM complex should activate endogenous NO production, showed fast activation followed by inhibition of l-Arg transport. The NOS inhibitor N-nitro-l-arginine methyl ester, but not blockers of downstream reactions, specifically removed this inhibitory component. These results demonstrate that NO acutely regulates its own biosynthesis by modulating the availability of l-Arg via cationic amino acid transporters.

scholarly journals Complex interactions of NO/cGMP/PKG systems on Ca2+ signaling in afferent arteriolar vascular smooth muscle

2010 ◽  
Vol 298 (1) ◽  
pp. H144-H151 ◽  
Author(s):  
Susan K. Fellner ◽  
William J. Arendshorst
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
No Production ◽  
No Donor ◽  
Complex Interactions ◽  
Resistance Vessels ◽  
Microsphere Method ◽  
Afferent Arterioles ◽  
Oxide Synthase

Little is known about the effects of nitric oxide (NO) and the cyclic GMP (cGMP)/protein kinase G (PKG) system on Ca2+ signaling in vascular smooth muscle cells (VSMC) of resistance vessels in general and afferent arterioles in particular. We tested the hypotheses that cGMP-, Ca2+-dependent big potassium channels (BKCa2+) buffer the Ca2+ response to depolarization by high extracellular KCl and that NO inhibits adenosine diphosphoribose (ADPR) cyclase, thereby reducing the Ca2+-induced Ca2+ release. We isolated rat afferent arterioles, utilizing the magnetized microsphere method, and measured cytosolic Ca2+ concentration ([Ca2+]i) with fura-2, a preparation in which endothelial cells do not participate in [Ca2+]i responses. KCl (50 mM)-induced depolarization causes an immediate increase in [Ca2+]i of 151 nM. The blockers Nω-nitro-l-arginine methyl ester (of nitric oxide synthase), 1,2,4-oxodiazolo-[4,3- a]quinoxalin-1-one (ODQ, of guanylyl cyclase), KT-5823 (of PKG activation), and iberiotoxin (IBX, of BKCa2+ activity) do not alter the [Ca2+]i response to KCl, suggesting no discernible endogenous NO production under basal conditions. The NO donor sodium nitroprusside (SNP) reduces the [Ca2+]i response to 77 nM; IBX restores the response to control values. These data show that activation of BKCa2+ in the presence of NO/cGMP provides a brake on KCl-induced [Ca2+]i responses. Experiments with the inhibitor of cyclic ADPR 8-bromo-cyclic ADPR (8-Br-cADPR) and SNP + downstream inhibitors of PKG and BKCa2+ suggest that NO inhibits ADPR cyclase in intact arterioles. When we pretreat afferent arterioles with 8-bromoguanosine 3′,5′-cyclic monophosphate (8-Br-cGMP; 10 μM), the response to KCl is 143 nM. However, in the presence of both IBX and 8-Br-cGMP, we observe a surprising doubling of the [Ca2+]i response to KCl. In summary, we present evidence for effects of the NO/cGMP/PKG system to reduce [Ca2+]i, via activation of BKCa2+ and possibly by inhibition of ADPR cyclase, and to increase [Ca2+]i, by a mechanism(s) yet to be defined.

Angiotensin II decreases inducible nitric oxide synthase expression in rat astroglial cultures

1995 ◽  
Vol 268 (3) ◽  
pp. C700-C707 ◽  
Author(s):  
L. J. Chandler ◽  
K. Kopnisky ◽  
E. Richards ◽  
F. T. Crews ◽  
C. Sumners
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Nitric Oxide Synthase ◽  
Receptor Antagonist ◽  
Maximal Response ◽  
No Production ◽  
Dependent Manner ◽  
Ang Ii ◽  
Subsequent Formation ◽  
Oxide Synthase

Consistent with stimulation of expression of an inducible form of nitric oxide synthase (iNOS), exposure of rat astroglial cultures to lipopolysaccharide (LPS) caused a time-dependent increase in the accumulation of nitrite in the culture media. Addition of the peptide angiotensin II (ANG II) with LPS decreased subsequent formation of nitrite in a concentration-dependent manner (concentration inhibiting 50% of maximal response approximately 1 nM). The ANG II effect could be blocked by the ANG II type 1 (AT1 receptor antagonist losartan but not by the ANG II type 2 (AT2) receptor antagonist PD-123177. ANG II had no effect on nitrite formation stimulated by a combination of inflammatory cytokines (interleukin-1 beta, tumor necrosis factor-alpha, and interferon-gamma). A brief 10-min exposure to ANG II was sufficient to cause an approximately 30% inhibition of the LPS response, with maximal inhibition of approximately 65% after 3 h, and occurred only when ANG II was added during the iNOS induction phase. Consistent with partial inhibition of LPS-stimulated expression of iNOS, ANG II reduced the levels of both iNOS mRNA and iNOS protein. These results demonstrate that ANG II can decrease LPS-stimulated NO production in astroglia by inhibiting induction of iNOS expression.

Fire Ant Venom Alkaloid, Isosolenopsin A, a Potent and Selective Inhibitor of Neuronal Nitric Oxide Synthase

2003 ◽  
Vol 22 (2) ◽  
pp. 81-86 ◽  
Author(s):  
G. B. Yi ◽  
D. Mc Clendon ◽  
D. Desaiah ◽  
J. Goddard ◽  
A. Lister ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inhibitory Activity ◽  
Systemic Toxicity ◽  
Fire Ant ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Nos Inhibitors ◽  
Oxide Synthase ◽  
Nos Isoforms

Massive, multiple fire ant, Solenopsis invicta, stings are often treated aggressively, particularly in the elderly, despite limited evidence of systemic toxicity due to the venom. Over 95% of the S. invicta venom is composed of piperidine alkaloid components, whose toxicity, if any, is unknown. To assess a possible pharmacological basis for systemic toxicity, an alkaloid-rich, protein-free methanol extract of the venom from whole ants was assayed for inhibitory activity on the following nitric oxide synthase (NOS) isoforms, rat cerebellar neuronal (n NOS), bovine recombinant endothelial (e NOS), and murine recombinant immunologic (i NOS). Cytosolic NOS activity was determined by measuring the conversion of [3H]arginine to [3H]citrulline in vitro. Rat n NOS activity was inhibited significantly and in a concentration-dependent manner by the alkaloid-rich venom extract. For n NOS, enzyme activity was inhibited by approximately 50% with 0.33 ± 0.06 μgg of this venom extract, and over 95% inhibition of the three isoforms, n NOS, e NOS, and i NOS, was found with doses of 60 μg in 60-μl reaction mixture. These results indicate that the alkaloid components of S. invicta venom can produce potent inhibition of all three major NOS isoforms. Isosolenopsin A ( cis-2-methyl-6-undecylpiperidine), a naturally occurring fire ant piperidine alkaloid, was synthesized and tested for inhibitory activity against the three NOS isoforms. Enzyme activities for n NOS and e NOS were over 95% inhibited with 1000 μM of isosolenopsin A, whereas the activity of i NOS was inhibited by only about 20% at the same concentration. The IC50 for each of three NOS isoforms was approximately 18 ± 3.9 μM for n NOS, 156 ± 10 μM for e NOS, and >1000 μM for i NOS, respectively. Kinetic studies showed isosolenopsin A inhibition to be noncompetitive with L-arginine ( Ki = 19 ± 2 μM). The potency of isosolenopsin A as an inhibitor of n NOS compares favorably with the inhibitory potency of widely used n NOS inhibitors. Inhibition of NOS isoforms by isosolenopsin A and structurally similar compounds may have toxicological significance with respect to adverse reactions to fire ant stings.

Differential responses of hydrogen peroxide, lipid peroxidation and antioxidant enzymes in Azolla microphylla exposed to paraquat and nitric oxide

Biologia ◽  
2012 ◽  
Vol 67 (6) ◽  
Author(s):  
Anjuli Sood ◽  
Charu Kalra ◽  
Sunil Pabbi ◽  
Prem Uniyal
Keyword(s):  
Nitric Oxide ◽  
Reactive Oxygen Species ◽  
Lipid Peroxidation ◽  
Antioxidative Enzymes ◽  
Guaiacol Peroxidase ◽  
Dependent Manner ◽  
Oxygen Species ◽  
Concentration Dependent Manner ◽  
No Donor ◽  
Azolla Microphylla

AbstractThe present investigation was carried out to decipher the interplay between paraquat (PQ) and exogenously applied nitric oxide (NO) in Azolla microphylla. The addition of PQ (8 μM) increased the activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) by 1.7, 2.7, 3.9 and 1.9 folds respectively than that control in the fronds of Azolla. The amount of H2O2 was also enhanced by 2.7 times in the PQ treated plants than that of control. The supplementation of sodium nitroprusside (SNP) from 8–100 μM along with PQ, suppressed the activities of antioxidative enzymes and the amount of H2O2 compared to PQ alone. The drop in the activity of antioxidative enzymes — SOD, GPX, CAT and APX was highest (39.9%, 48.4%, 41.6% and 41.3% respectively) on the supplementation of 100 μM SNP with PQ treated fronds compared to PQ alone. The addition of NO scavengers along with NO donor in PQ treated fronds neutralized the effect of exogenously supplied NO. This indicates that NO can effectively protect Azolla against PQ toxicity by quenching reactive oxygen species. However, 200 μM of SNP reversed the protective effect of lower concentration of NO donor against herbicide toxicity. Our study clearly suggests that (i) SNP released NO can work both as cytoprotective and cytotoxic in concentration dependent manner and (ii) involvement of NO in protecting Azolla against PQ toxicity.

scholarly journals Differential regulation of metabolism by nitric oxide andS-nitrosothiols in endothelial cells

2011 ◽  
Vol 301 (3) ◽  
pp. H803-H812 ◽  
Author(s):  
Anne R. Diers ◽  
Katarzyna A. Broniowska ◽  
Victor M. Darley-Usmar ◽  
Neil Hogg
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Oxidative Phosphorylation ◽  
Metabolic Pathways ◽  
Nitrosative Stress ◽  
Surrogate Marker ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
No Donor

S-nitrosation of thiols in key proteins in cell signaling pathways is thought to be an important contributor to nitric oxide (NO)-dependent control of vascular (patho)physiology. Multiple metabolic enzymes are targets of both NO and S-nitrosation, including those involved in glycolysis and oxidative phosphorylation. Thus it is important to understand how these metabolic pathways are integrated by NO-dependent mechanisms. Here, we compared the effects of NO and S-nitrosation on both glycolysis and oxidative phosphorylation in bovine aortic endothelial cells using extracellular flux technology to determine common and unique points of regulation. The compound S-nitroso-l-cysteine (l-CysNO) was used to initiate intracellular S-nitrosation since it is transported into cells and results in stable S-nitrosation in vitro. Its effects were compared with the NO donor DetaNONOate (DetaNO). DetaNO treatment caused only a decrease in the reserve respiratory capacity; however, l-CysNO impaired both this parameter and basal respiration in a concentration-dependent manner. In addition, DetaNO stimulated extracellular acidification rate (ECAR), a surrogate marker of glycolysis, whereas l-CysNO stimulated ECAR at low concentrations and inhibited it at higher concentrations. Moreover, a temporal relationship between NO- and S-nitrosation-mediated effects on metabolism was identified, whereby NO caused a rapid impairment in mitochondrial function, which was eventually overwhelmed by S-nitrosation-dependent processes. Taken together, these results suggest that severe pharmacological nitrosative stress may differentially regulate metabolic pathways through both intracellular S-nitrosation and NO-dependent mechanisms. Moreover, these data provide insight into the role of NO and related compounds in vascular (patho)physiology.

Activation of Nitric Oxide Release and Oxidative Metabolism by Leukotrienes B4, C4, and D4 in Human Polymorphonuclear Leukocytes

Blood ◽  
1999 ◽  
Vol 93 (4) ◽  
pp. 1399-1405 ◽  
Author(s):  
Gerd Lärfars ◽  
Frédérique Lantoine ◽  
Marie-Aude Devynck ◽  
Jan Palmblad ◽  
Hans Gyllenhammar
Keyword(s):  
Nitric Oxide ◽  
Rank Order ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Kinetic Properties ◽  
No Production ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cysteinyl Leukotrienes ◽  
Mediators Of Inflammation

Abstract Because arachidonate metabolites are potent mediators of inflammation, we have studied the effects of leukotriene B4(LTB4) and the cysteinyl leukotrienes C4 and D4 (LTC4 and LTD4) on the release of nitric oxide (NO), in vitro, by human polymorphonuclear granulocytes (PMN). Two independent and highly sensitive real-time methods were used for these studies, ie, the NO-dependent oxidation of oxyhemoglobin (HbO2) to methemoglobin and a NO-sensitive microelectrode. When activated with LTB4, LTC4, or LTD4, but not with other lipoxygenase products such as 5S-HETE, 5-oxo-ETE or 5S,12S-diHETE, PMN produced NO in a stimulus- and concentration-dependent manner. The rank order of potency was LTB4 = LTC4 > LTD4, corresponding to 232 ± 50 pmol of NO/106 PMN for 100 nmol/L LTB4 after 30 minutes. The kinetic properties of the responses were similar for all three leukotrienes with a maximum response at 13 ± 3 minutes. Cysteinyl leukotriene and LTB4 antagonists inhibited the agonist-induced NO production by 70%, and treatment with Bordetella pertussis toxin, or chelation of cytosolic Ca2+, [Ca2+]i, also efficiently inhibited this response. In contrast, treatment of PMN with cytochalasin B (5 μg/mL) enhanced the LTB4-induced NO formation by 86%. Thus, this is the first demonstration that the cysteinyl leukotrienes LTC4 and LTD4, as well as LTB4, activate NO release from human PMN by surface receptor, G-protein and [Ca2+]i-dependent mechanisms. This effect differs from activation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, for which only LTB4is an activator.

Nitric oxide mediates elicitor-induced saponin synthesis in cell cultures of Panax ginseng

2003 ◽  
Vol 30 (8) ◽  
pp. 901 ◽  
Author(s):  
Xiangyang Hu ◽  
Steven J. Neill ◽  
Weiming Cai ◽  
Zhangcheng Tang
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Protein Phosphatase ◽  
Kinase Inhibitor ◽  
Squalene Epoxidase ◽  
No Production ◽  
No Donor ◽  
Phosphatase Inhibitor ◽  
Protein Phosphatase Inhibitor ◽  
Oxide Synthase

The elicitor oligogalacturonic acid (OGA) stimulated nitric oxide (NO) accumulation in the growth medium of ginseng suspension cultures and induced increased nitric oxide synthase (NOS) activity in ginseng cells. OGA also stimulated accumulation of saponin, transcription of genes encoding squalene synthase (sqs) and squalene epoxidase (sqe), two early enzymes of saponin synthesis, and the accumulation of β-amyrin synthase protein (β-AS). Saponin accumulation, sqs and sqe gene expression, and increases in β-AS content were also induced by exposure to NO via the NO donor sodium nitroprusside (SNP). Inhibitors of mammalian nitric oxide synthase reduced both OGA-induced NO accumulation and NOS activity, suggesting that OGA-induced NO production occurs via a NOS-like enzyme. OGA-induced accumulation of β-AS and saponin, and transcription of sqs and sqe, were suppressed by treatments that removed NO or inhibited its production, indicating a role for NO in mediating OGA effects on these defence responses. NO accumulation and increased NOS activity were inhibited by calcium channel inhibitors and a protein kinase inhibitor, but not by a protein phosphatase inhibitor, indicating the requirement for calcium and protein phosphorylation during OGA-induced NO production. Saponin production and transcription, and accumulation of saponin biosynthetic genes and enzymes were also suppressed by these treatments, as well as by the protein phosphatase inhibitor okadaic acid.

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