Nitric oxide-epoxygenase interactions and arachidonate-induced dilation of rat renal microvessels

2003 ◽  
Vol 285 (5) ◽  
pp. H2054-H2063 ◽  
Author(s):  
I. T. Udosen ◽  
H. Jiang ◽  
H. C. Hercule ◽  
A. O. Oyekan
Keyword(s):  
Nitric Oxide ◽  
Electromechanical Coupling ◽  
Epoxyeicosatrienoic Acid ◽  
No Donor ◽  
No Donors ◽  
Channel Opener ◽  
Gap Junctional ◽  
Spermine Nonoate ◽  
Cytochrome P 450 ◽  
Dilatory Effect

Nitric oxide (NO) is an inhibitor of hemoproteins including cytochrome P-450 enzymes. This study tested the hypothesis that NO inhibits cytochrome P-450 epoxygenase-dependent vascular responses in kidneys. In rat renal pressurized microvessels, arachidonic acid (AA, 0.03–1 μM) or bradykinin (BK, 0.1–3 μM) elicited NO- and prostanoid-independent vasodilation. Miconazole (1.5 μM) or 6-(2-propargyloxyphenyl)hexanoic acid (30 μM), both of which are inhibitors of epoxygenase enzymes, or the fixing of epoxide levels with 11,12-epoxyeicosatrienoic acid (11,12-EET; 1 and 3 μM) inhibited these responses. Apamin (1 μM), which is a large-conductance Ca2+-activated K+ (BKCa) channel inhibitor, or 18α-glycyrrhetinic acid (30 μM), which is an inhibitor of myoendothelial gap junctional electromechanical coupling, also inhibited these responses. NO donors spermine NONOate (1 and 3 μM) or sodium nitroprusside (0.3 and 3 μM) but not 8-bromo-cGMP (100 μM), which is an analog of cGMP (the second messenger of NO), blunted the dilation produced by AA or BK in a reversible manner without affecting that produced by hydralazine. However, the non-NO donor hydralazine did not affect the dilatory effect of AA or BK. Spermine NONOate did not affect the dilation produced by 11,12-EET, NS-1619 (a BKCa channel opener), or cromakalim (an ATP-sensitive K+ channel opener). AA and BK stimulated EET production, whereas hydralazine had no effect. On the other hand, spermine NONOate (3 μM) attenuated basal (19 ± 7%; P < 0.05) and AA stimulation (1 μM, 29 ± 9%; P < 0.05) of renal preglomerular vascular production of all regioisomeric EETs: 5,6-; 8,9-; 11,12-; and 14,15-EET. These results suggest that NO directly and reversibly inhibits epoxygenase-dependent dilation of rat renal microvessels without affecting the actions of epoxides on K+ channels.

NO inhibits Na+-K+-2Cl−cotransport via a cytochrome P-450-dependent pathway in renal epithelial cells (MMDD1)

2003 ◽  
Vol 284 (6) ◽  
pp. F1235-F1244 ◽  
Author(s):  
Hao He ◽  
Tiina Podymow ◽  
Joseph Zimpelmann ◽  
Kevin D. Burns
Keyword(s):  
Nitric Oxide ◽  
Cytosolic Calcium ◽  
Inhibitory Effect ◽  
Epoxyeicosatrienoic Acid ◽  
No Donors ◽  
Dependent Inhibition ◽  
A Cell ◽  
Oxide Synthase ◽  
Cytochrome P 450 ◽  
Dependent Pathway

Nitric oxide (NO) exerts direct effects on nephron transport. We determined the effect of NO on Na+-K+-2Cl− cotransport in a cell line (MMDD1) with properties of macula densa. Na+-K+-2Cl− cotransport was measured as bumetanide-sensitive 86Rb+ uptake in the presence of ouabain. MMDD1 cells expressed mRNA for the neuronal isoform of nitric oxide synthase, as well as NKCC1 and NKCC2(B) isoforms of the Na+-K+-2Cl−cotransporter. Preincubation of cells with the NO donors sodium nitroprusside (SNP) or S-nitroso- N-acetylpenicillamine (SNAP) caused concentration-dependent inhibition of Na+-K+-2Cl− cotransport. Both apical and basolateral Na+-K+-2Cl−cotransport was inhibited by NO donors. SNP or SNAP had no significant effect on cellular levels of cGMP, cAMP, cytosolic calcium, or phosphorylation of ERK1 and ERK2. In contrast, the inhibitors of cytochrome P-450, 1-aminobenzotriazole (ABT; 10−3 M) or ketoconazole (1.5 × 10−5 M), completely reversed the inhibitory effect of SNAP on apical or basolateral Na+-K+-2Cl−cotransport [apical: control 1.18 ± 0.15 vs. SNAP (10−4 M) 0.41 ± 0.05 pmol · mg−1 · 5 min−1; P < 0.001; SNAP (10−4M) + ABT 1.32 ± 0.10 pmol · mg−1 · 5 min−1; P = not significant vs. control; n = 5]. The cytochrome P-450 epoxyeicosatrienoic acid (EET) metabolite 14,15-EET (5 × 10−7 M) inhibited both apical and basolateral cotransport, whereas 8,9-EET and 11,12-EET had no significant effect. Although 20-hydroxyeicosatetraenoic acid inhibited apical cotransport, the inhibitor of ω-hydroxylase activity HET0016 did not reverse SNAP-mediated inhibition of apical cotransport. These data indicate that NO inhibits apical and basolateral Na+-K+-2Cl− cotransport in MMDD1 cells. The results suggest that the inhibitory pathway is independent of cGMP and might involve stimulation of a cytochrome P-450-dependent pathway.

Nitric oxide preconditioning regulates endothelial monolayer integrity via the heat shock protein 90-soluble guanylate cyclase pathway

2007 ◽  
Vol 292 (2) ◽  
pp. H893-H903 ◽  
Author(s):  
Galina N. Antonova ◽  
Connie M. Snead ◽  
Alexander S. Antonov ◽  
Christiana Dimitropoulou ◽  
Richard C. Venema ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Cell Injury ◽  
Soluble Guanylate Cyclase ◽  
Heat Shock Protein 90 ◽  
Protective Effects ◽  
No Donor ◽  
Spermine Nonoate

Large (pathological) amounts of nitric oxide (NO) induce cell injury, whereas low (physiological) NO concentrations often ameliorate cell injury. We tested the hypotheses that pretreatment of endothelial cells with low concentrations of NO (preconditioning) would prevent injury induced by high NO concentrations. Apoptosis, induced in bovine aortic endothelial cells (BAECs) by exposing them to either 4 mM sodium nitroprusside (SNP) or 0.5 mM N-(2-aminoethyl)- N-(2-hydroxy-2-nitrosohydrazino)-1,2-ethylenediamine (spermine NONOate) for 8 h, was abolished by 24-h pretreatment with either 100 μM SNP, 10 μM spermine NONOate, or 100 μM 8-bromo-cGMP (8-Br-cGMP). Repair of BAECs following wounding, measured as the recovery rate of transendothelial electrical resistance, was delayed by 8-h exposure to 4 mM SNP, and this delay was significantly attenuated by 24-h pretreatment with 100 μM SNP. NO preconditioning produced increased association and expression of soluble guanyl cyclase (sGC) and heat shock protein 90 (HSP90). The protective effect of NO preconditioning, but not the injurious effect of 4 mM SNP, was abolished by either a sGC activity inhibitor 1H-[1,2,4]oxadiazolo-[4,3- a]quinoxalin-1-one (ODQ) or a HSP90 binding inhibitor (radicicol) and was mimicked by 8-Br-cGMP. We conclude that preconditioning with a low dose of NO donor accelerates repair and maintains endothelial integrity via a mechanism that includes the HSP90/sGC pathway. HSP90/sGC may thus play a role in the protective effects of NO-generating drugs from injurious stimuli.

Abstract P607: Nitric Oxide (NO) Regulates Paracellular Permselectivity in Isolated, Perfused Rat Thick Ascending Limbs through Claudin-19

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Casandra M Monzon ◽  
Jeffrey Garvin
Keyword(s):  
Nitric Oxide ◽  
Control Period ◽  
Sprague Dawley ◽  
Permeability Ratio ◽  
Ionic Selectivity ◽  
No Donor ◽  
Sprague Dawley Rats ◽  
Spermine Nonoate ◽  
Dilution Potential ◽  
Cl Permeability

About 50% of the Na reabsorbed in thick ascending limbs (TALs) traverses the paracellular pathway. The ionic selectivity of this route is regulated by claudins in the tight junctions. TALs express claudin-19 which has been reported to regulate TAL Na permeability. We showed that nitric oxide (NO) decreases Na/Cl permeability ratio (PNa/PCl) in TALs by increasing the absolute permeabilities of both ions though PCl increased more. However, whether NO affects paracellular permeability via claudin-19 is unknown. We hypothesize that NO regulates the paracellular permselectivity in TALs through this claudin. To test this we perfused TALs from Sprague Dawley rats and measured dilution potentials (a measure of permselectivity) with and without exogenously-added or endogenously-produced NO in the presence or absence of an antibody against an extracellular domain of claudin-19 or Tamm-Horsfall protein (control). Dilution potentials were generated by reducing bath NaCl from 141 to 32 mM. For the NO donor spermine NONOate (SPM): during the control period, the dilution potential was -9.3 ± 1.8 mV. After SPM (200 μM), it was -6.7 ± 1.6 mV (n = 6; p < 0.003). In the presence of the claudin-19 antibody, SPM had no significant effect on dilution potentials (claudin-19 antibody alone: -12.7 ± 2.1 mV vs claudin-19 antibody + SPM: -12.9 ± 2.4 mV; n = 6). The claudin-19 antibody alone had no effect on dilution potentials. In the presence of the Tamm-Horsfall protein, the effect of SPM was still present (Tamm-Horsfall protein antibody alone: -9.7 ± 1.0 mV; Tamm-Horsfall protein antibody + SPM: -6.3 ± 1.1 mV, p<0.006, n = 6). For experiments with endogenously-produced NO, L-arginine the substrate for NO synthase was added. During the control period, the dilution potential was -11.0 ± 1.1 mV. After L-arginine (500 μM) treatment, they were -9.0 ± 1.2 mV (n = 9; p < 0.05). In the presence of the claudin-19 antibody, L-arginine had no significant effect on dilution potentials (claudin-19 antibody alone: -10.1 ± 0.9 mV vs claudin-19 antibody + L-arginine: -10.1 ± 1.0 mV; n = 9). In the presence of the Tamm-Horsfall protein, the effect of L-arginine was still present. We conclude that the actions of NO on the paracellular permselectivity in thick ascending limbs are at least in part mediated by claudin-19.

Nitric oxide stimulates the stress-activated protein kinase p38 in rat renal mesangial cells

1999 ◽  
Vol 202 (6) ◽  
pp. 655-660
Author(s):  
A. Huwiler ◽  
J. Pfeilschifter
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase ◽  
P38 Mapk ◽  
Mesangial Cells ◽  
Mapk Pathway ◽  
Mapk Cascade ◽  
No Donor ◽  
No Donors ◽  
Mitogen Activated Protein ◽  
Rapid Activation

Nitric oxide (NO) has gained increased attention as a diffusible universal messenger that plays a crucial role in the pathogenesis of inflammatory and autoimmune diseases. Recently, we reported that exogenous NO is able to activate the stress-activated protein kinase (SAPK) cascade in mesangial cells. Here, we demonstrate that exposure of glomerular mesangial cells to compounds releasing NO, including spermine-NO and (Z)-1-?N-methyl-N-[6-(N-methylammoniohexyl)amino]diazen?-1-ium+ ++-1,2-diolate (MAHMA-NO), results in an activation of the stress-activated p38-mitogen-activated protein kinase (p38-MAPK) cascade as measured by the phosphorylation of the activator of transcription factor-2 (ATF2) in an immunocomplex kinase assay. Activation of the p38-MAPK cascade by a short stimulation (10 min) with the NO donor MAHMA-NO causes a large increase in ATF2 phosphorylation that is several times greater than that observed after stimulation with interleukin-1beta, a well-known activator of the p38-MAPK pathway. Time course studies reveal that MAHMA-NO causes rapid and maximal activation of p38-MAPK after 10 min of stimulation and that activation declines to basal levels within 60 min. The longer-lived NO donor spermine-NO causes a comparable rapid activation of the p38-MAPK pathway; however, the increased activation state of p38-MAPK was maintained for several hours before control values were reattained after 24 h of stimulation. Furthermore, the NO donors also activated the classical extracellular signal-regulated kinase (ERK) p44-MAPK cascade as shown by phosphorylation of the specific substrate cytosolic phospholipase A2 in an immunocomplex kinase reaction. Both MAHMA-NO and spermine-NO cause a rapid activation of p44-MAPK after 10 min of stimulation. Interestingly, there is a second delayed peak of p44-MAPK activation after 4–24 h of stimulation with NO donors. These results suggest that there is a differential activation pattern for stress-activated and mitogen-activated protein kinases by NO and that the integration of these signals may lead to specific cell responses.

Characterization of endothelium-derived hyperpolarizing factor in the human forearm microcirculation

2001 ◽  
Vol 280 (6) ◽  
pp. H2470-H2477 ◽  
Author(s):  
Julian P. J. Halcox ◽  
Suresh Narayanan ◽  
Laura Cramer-Joyce ◽  
Rita Mincemoyer ◽  
Arshed A. Quyyumi
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Sodium Nitroprusside ◽  
Forearm Blood Flow ◽  
Human Subjects ◽  
Epoxyeicosatrienoic Acid ◽  
Healthy Human ◽  
Human Forearm ◽  
Oxide Synthase ◽  
Cytochrome P 450

The identity of endothelium-dependent hyperpolarizing factor (EDHF) in the human circulation remains controversial. We investigated whether EDHF contributes to endothelium-dependent vasomotion in the forearm microvasculature by studying the effect of K+ and miconazole, an inhibitor of cytochrome P-450, on the response to bradykinin in healthy human subjects. Study drugs were infused intra-arterially, and forearm blood flow was measured using strain-gauge plethysmography. Infusion of KCl (0.33 mmol/min) into the brachial artery caused baseline vasodilation and inhibited the vasodilator response to bradykinin, but not to sodium nitroprusside. Thus the incremental vasodilation induced by bradykinin was reduced from 14.3 ± 2 to 7.1 ± 2 ml · min−1 · 100 g−1( P < 0.001) after KCl infusion. A similar inhibition of the bradykinin ( P = 0.014), but not the sodium nitroprusside (not significant), response was observed with KCl after the study was repeated during preconstriction with phenylephrine to restore resting blood flow to basal values after KCl. Miconazole (0.125 mg/min) did not inhibit endothelium-dependent or -independent responses to ACh and sodium nitroprusside, respectively. However, after inhibition of cyclooxygenase and nitric oxide synthase with aspirin and N G-monomethyl-l-arginine, the forearm blood flow response to bradykinin ( P = 0.003), but not to sodium nitroprusside (not significant), was significantly suppressed by miconazole. Thus nitric oxide- and prostaglandin-independent, bradykinin-mediated forearm vasodilation is suppressed by high intravascular K+ concentrations, indicating a contribution of EDHF. In the human forearm microvasculature, EDHF appears to be a cytochrome P-450 derivative, possibly an epoxyeicosatrienoic acid.

Nitric oxide affects sarcoplasmic calcium release in skeletal myotubes

2001 ◽  
Vol 91 (5) ◽  
pp. 2117-2124 ◽  
Author(s):  
Leo M. A. Heunks ◽  
Herwin A. Machiels ◽  
P. N. Richard Dekhuijzen ◽  
Y. S. Prakash ◽  
Gary C. Sieck
Keyword(s):  
Nitric Oxide ◽  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Similar Data ◽  
Release Channel ◽  
No Donor ◽  
No Donors ◽  
Subsequent Exposure ◽  
Skeletal Myotubes ◽  
Dose Dependent

In the present study, we used real-time confocal microscopy to examine the effects of two nitric oxide (NO) donors on acetylcholine (ACh; 10 μM)- and caffeine (10 mM)-induced intracellular calcium concentration ([Ca2+]i) responses in C2C12 mouse skeletal myotubes. We hypothesized that NO reduces [Ca2+]i in activated skeletal myotubes through oxidation of thiols associated with the sarcoplasmic reticulum Ca2+-release channel. Exposure to diethylamine NONOate (DEA-NO) reversibly increased resting [Ca2+]i level and resulted in a dose-dependent reduction in the amplitude of ACh-induced [Ca2+]i responses (25 ± 7% reduction with 10 μM DEA-NO and 78 ± 14% reduction with 100 μM DEA-NO). These effects of DEA-NO were partly reversible after subsequent exposure to dithiothreitol (10 mM). Preexposure to DEA-NO (1, 10, and 50 μM) also reduced the amplitude of the caffeine-induced [Ca2+]i response. Similar data were obtained by using the chemically distinct NO donor S-nitroso- N-acetyl-penicillamine (100 μM). These results indicate that NO reduces sarcoplasmic reticulum Ca2+ release in skeletal myotubes, probably by a modification of hyperreactive thiols present on the ryanodine receptor channel.

scholarly journals Nitric oxide inhibits sodium/hydrogen exchange activity in the thick ascending limb

1999 ◽  
Vol 277 (3) ◽  
pp. F377-F382 ◽  
Author(s):  
Jeffrey L. Garvin ◽  
Nancy J. Hong
Keyword(s):  
Nitric Oxide ◽  
Steady State ◽  
Hydrogen Exchange ◽  
Thick Ascending Limb ◽  
Acid Base Balance ◽  
No Donor ◽  
Base Balance ◽  
Dimethyl Amiloride ◽  
Oxide Synthase ◽  
Spermine Nonoate

Nitric oxide (NO) inhibits transport in various nephron segments, and the thick ascending limb (TAL) expresses nitric oxide synthase (NOS). However, the effects of NO on TAL transport have not been extensively studied. We tested the hypothesis that NO inhibits apical and basolateral Na+/H+exchange by the TAL by measuring intracellular pH (pHi) of isolated, perfused rat TALs using the fluorescent dye 2′,7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). The NO donor spermine NONOate (SPM, 10 μM) decreased steady-state pHi in medullary TALs from 7.18 ± 0.13 to 7.13 ± 0.14 ( P < 0.02), whereas controls did not decrease significantly. We next measured the buffering capacity of medullary TALs and the rate at which they recovered from acid loads to investigate the mechanism whereby NO reduces steady-state pHi. SPM decreased H+ flux ( J H) from 2.41 ± 0.66 to 0.97 ± 0.19 pmol ⋅ min−1 ⋅ mm−1, 55%. To assure that the decrease in J H was due to NO, another donor, nitroglycerin (NTG; 10 μM), was used. NTG decreased J H from 1.65 ± 0.11 to 1.07 ± 0.24 pmol ⋅ min−1 ⋅ mm−1, 37%. To determine the relative contributions of the apical and basolateral Na+/H+exchangers, 5-( N, N-dimethyl)amiloride (DMA; 100 μM) was added to either bath or lumen. With DMA added to the bath, SPM decreased J H from 4.78 ± 1.08 to 2.74 ± 0.54 pmol ⋅ min−1 ⋅ mm−1, an inhibition of 41%; and with DMA added to the lumen, SPM decreased J H from 2.31 ± 0.29 to 1.74 ± 0.27 pmol ⋅ min−1 ⋅ mm−1, a reduction of 26%. Addition of DMA alone to both bath and lumen resulted in an 87% inhibition of J H. We conclude that NO inhibits both apical and basolateral Na+/H+exchangers and consequently may play an important role in regulating pHi and may alter acid/base balance by directly affecting bicarbonate absorption in the TAL.

Sodium Nitrite Increases Regional Blood Flow in Patients with Sickle Cell Disease.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2328-2328
Author(s):  
A. Kyle Mack ◽  
Roberto F. Machado ◽  
Vandana Sachdev ◽  
Mark T. Gladwin ◽  
Gregory J. Kato
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Forearm Blood Flow ◽  
Regional Blood Flow ◽  
Cell Disease ◽  
No Donor ◽  
No Donors ◽  
Before And After

Abstract Patients with sickle cell disease have decreased nitric oxide bioavailability, and studies from several groups have confirmed a blunted response to various NO donors in humans and mice with sickle cell disease. Recently published studies show that nitrite induces vasodilation in humans, apparently mediated by conversion of nitrite to NO. This study is designed to determine the potential therapeutic effect of intra-arterial nitrite infusion to restore nitric oxide dependent blood flow in the forearms of patients with sickle cell disease. Venous occlusion strain gauge plethysmography is used to measure the change of forearm blood flow in patients with sickle cell disease, before and after sequential brachial artery infusions of increasing doses of sodium nitrite. In addition, NO responsiveness before and after nitrite infusion is measured by test doses of the NO donor sodium nitroprusside (SNP). Six patients have completed the study and enrollment is continuing. These data indicate that nitrite promotes regional blood flow in patients with sickle cell disease, albeit with a blunted response compared to our healthy control subjects, in whom we previously have found increased blood flow up to 187% with comparable dosing. The significant but blunted response is consistent with the state of nitric oxide resistance to NO donors that has been seen by several groups in patients and mice with SCD. Additionally, we find in these patients that nitrite partially restores SNP responsiveness, with baseline maximal SNP responses more than doubling on average following nitrite infusion, although this finding is preliminary. No adverse effects of nitrite were seen in these six patients. Our early results support a role for nitrite as an NO donor effective in restoring NO-dependent blood flow in patients with sickle cell disease. Additional translational studies are warranted to evaluate the therapeutic effects of systemic nitrite dosing. Table 1. Forearm Blood Flow Response to Nitrite Infusion Nitrite Dose (micromole/min) Sickle Cell Disease Historical Controls P&lt; .0001 (ANOVA) 0.4 5 +/−7.2% N=6 22 +/−3.2% N=10 4 15 +/− 11% N=6 Not infused 40 49 +/− 8.9% N=6 187 +/− 16%N=18 Table 2. Nitrite Effect on Nitroprusside Responsiveness SNP Dose (micrograms/min) Pre-Nitrite Post-Nitrite P= .02 (RM-ANOVA) N=6 0.8 +21 +/− 5.6% +33 +/− 8.3% 1.6 +15 +/− 5.9% +62 +/− 15.1% 3.2 +29 +/− 6.3% +67 +/− 11.5%

Regulation of metalloproteinases by nitric oxide in human trophoblast cells in culture

2001 ◽  
Vol 13 (6) ◽  
pp. 411 ◽  
Author(s):  
Virginia Novaro ◽  
Alejandro Colman-Lerner ◽  
Felipe Vadillo Ortega ◽  
Alicia Jawerbaum ◽  
Dante Paz ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Embryo Implantation ◽  
No Production ◽  
Trophoblast Cells ◽  
Human Trophoblast ◽  
No Donors ◽  
Multinucleated Cells ◽  
Nos Inhibitors ◽  
Spermine Nonoate

The process of embryo implantation requires extensive remodelling of the endometrial extracellular matrix, a function largely performed by matrix-degrading metalloproteinases (MMPs). In the present study, we used trophoblast cells isolated from human term placentas to study the regulation of MMPs by nitric oxide (NO). Using a combination of zymography, Western blot and indirect immunofluorescence, we showed that MMP-2 and MMP-9 are increased during the conversion from low-motile cytotrophoblast cells to the highly motile and differentiated syncytiotrophoblast multinucleated cells. We also observed an increase in NO production and NO synthase (NOS) expression during this cellular differentiation process. In addition, we demonstrated a positive regulatory role of NO on the activity and protein expression of MMP-2 and MMP-9, because NO donors (NOC-18 and spermine-NONOate) or the NOS substrate (L-arginine) stimulate, whereas NOS inhibitors (NG-nitro-L-arginine methyl ester and NG-monomethyl-L-arginine) reduce the expression and gelatinolytic activity of MMP-2 and MMP-9 in isolated trophoblast cells. Taken together, these results suggest that, in differentiating trophoblasts, NO regulates the induction of matrix-degrading proteases required for invasion during embryo implantation.

scholarly journals Nitric oxide regulates nitric oxide synthase-2 gene expression by inhibiting NF-κB binding to DNA

1997 ◽  
Vol 322 (2) ◽  
pp. 609-613 ◽  
Author(s):  
Song Kyu PARK ◽  
Hsin Lee LIN ◽  
Sean MURPHY
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Interferon Γ ◽  
No Production ◽  
No Donor ◽  
Nitric Oxide Synthase 2 ◽  
Oxide Synthase ◽  
Spermine Nonoate ◽  
Dna Complex

Treatment of astroglial cells with interleukin 1β and interferon γ transcriptionally activates the nitric oxide synthase (NOS)-2 gene. The duration of mRNA expression is brief because of transcript instability. In addition, NO donors reduce the expression of NOS-2 mRNA dramatically by reducing the rate of transcription. In this study we observed that the NO donor, spermine NONOate did not inhibit the activation and translocation of NF-κB, a key transcription factor in the induction of NOS-2, but inhibited formation of the NF-κB–DNA complex. This effect was reversed by methaemoglobin (acting as an NO trap) and by the reducing agent dithiothreitol. Formation of the interferon-regulatory factor–DNA complex was unaffected by NO. These results suggest that NO can modulate its own production by interfering with NF-κB interaction with the promoter region of the NOS gene, a negative feedback effect that may be important for limiting NO production in vivo.

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