scholarly journals Urea Excretion and Arginase Activity as New Biomarkers for Nitrite Stress in Freshwater Aquatic Animals

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3521
Author(s):  
Gaetana Napolitano ◽  
Gianluca Fasciolo ◽  
Claudio Agnisola ◽  
Paola Venditti
Keyword(s):  
Nitric Oxide ◽  
Anthropogenic Activities ◽  
Arginase Activity ◽  
No Production ◽  
Uptake System ◽  
Urea Excretion ◽  
Chloride Uptake ◽  
New Biomarkers ◽  
Oxide Synthase

Background: In recent years, the concern has been growing on increasing aquatic nitrite levels due to anthropogenic activities. Crustaceans and fish easily uptake nitrite via the chloride uptake system of gills. High nitrite body levels may interfere with nitric oxide (NO) production by nitric oxide synthase (NOS). The arginase, which catalyzes arginine conversion to ornithine and urea, is central to NO homeostasis. In vivo, changes in the arginase activity alter urea body levels and urea excretion and modulate NOS by altering arginine availability for NO synthesis. Excess arginase activity may uncouple NOS and induce oxidative stress. Methods: We tested muscle arginase activity and urea excretion in two fish species, zebrafish and convict cichlid, and the crustacean Yamato shrimp, under sub-lethal nitrite stress. Results: Exposure to nitrite (2 mM in the fish, 1 mM in the shrimp) significantly increased blood nitrite concentration in all species. Concomitantly, nitrite stress significantly increased arginase activity, urea excretion, and urea levels in the blood. In Yamato shrimp, urea levels also increased in muscle. Conclusion: Our results agree with the hypothesis that nitrite stress affects NO homeostasis by arginase stimulation and urea excretion. These parameters might function as markers of sub-lethal nitrite stress in freshwater fish and crustaceans.

scholarly journals Effects of chitosan on nitric oxide production and inducible nitric oxide synthase activity and mRNA expression in weaned piglets

2018 ◽  
Vol 60 (No. 8) ◽  
pp. 359-366
Author(s):  
J. Li ◽  
B. Shi ◽  
S. Yan ◽  
L. Jin ◽  
Y. Guo ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Mrna Expression ◽  
Inducible Nitric Oxide Synthase ◽  
No Production ◽  
Weaned Piglets ◽  
Inos Activity ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

The effects of chitosan on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) activity and gene expression in vivo or vitro were investigated in weaned piglets. In vivo, 180 weaned piglets were assigned to five dietary treatments with six replicates. The piglets were fed on a basal diet supplemented with 0 (control), 100, 500, 1000, and 2000 mg chitosan/kg feed, respectively. In vitro, the peripheral blood mononuclear cells (PBMCs) from a weaned piglet were cultured respectively with 0 (control), 40, 80, 160, and 320 µg chitosan/ml medium. Results showed that serum NO concentrations on days 14 and 28 and iNOS activity on day 28 were quadratically improved with increasing chitosan dose (P < 0.05). The iNOS mRNA expressions were linearly or quadratically enhanced in the duodenum on day 28, and were improved quadratically in the jejunum on days 14 and 28 and in the ileum on day 28 (P < 0.01). In vitro, the NO concentrations, iNOS activity, and mRNA expression in unstimulated PBMCs were quadratically enhanced by chitosan, but the improvement of NO concentrations and iNOS activity by chitosan were markedly inhibited by N-(3-[aminomethyl] benzyl) acetamidine (1400w) (P < 0.05). Moreover, the increase of NO concentrations, iNOS activity, and mRNA expression in PBMCs induced by lipopolysaccharide (LPS) were suppressed significantly by chitosan (P < 0.05). The results indicated that the NO concentrations, iNOS activity, and mRNA expression in piglets were increased by feeding chitosan in a dose-dependent manner. In addition, chitosan improved the NO production in unstimulated PBMCs but inhibited its production in LPS-induced cells, which exerted bidirectional regulatory effects on the NO production via modulated iNOS activity and mRNA expression.

Short-term exposure to homocysteine depresses rat aortic contractility by an endothelium-dependent mechanism

2000 ◽  
Vol 78 (6) ◽  
pp. 500-506 ◽  
Author(s):  
S Wang ◽  
G Wright ◽  
J Harrah ◽  
R Touchon ◽  
W McCumbee ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Nitric Oxide Synthase ◽  
Contractile Response ◽  
Fold Increase ◽  
No Production ◽  
Short Term ◽  
Short Term Exposure ◽  
Oxide Synthase

The effect of short-term exposure to homocysteine (Hcy) on the contractile characteristics of rat aortic tissue was assessed both in vitro and in vivo. The contractile response of Hcy-treated aortic rings in culture for 1 or 4 days was unchanged from control responses. By comparison, aortic rings from animals injected with Hcy showed marked attenuation of response compared with controls injected with saline, cysteine or methionine. The contractile response to K+ was decreased within 24 hours of Hcy injection, whereas the response to both K+ (-27%) and noradrenaline (-56%) was significantly decreased by 4 days. In contrast, the contractile response to phorbol-12,13-dibutyrate was not different between Hcy and control groups. Intimal rubbing completely restored the responsiveness of Hcy-treated tissue to K+ and noradrenaline. By comparison, L-NAME only partially restored contractile responsiveness, while the cyclooxygenase inhibitor indomethacin had no effect on contractile attenuation induced by Hcy. Western blot analysis showed a 2-fold increase of endothelial nitric oxide synthase (eNOS) and a 3-fold increase in inducible nitric oxide synthase (iNOS) protein expression in the aortic endothelial cells from Hcy-injected rats. The results indicate an early detectable effect of Hcy on the in vivo contractile properties of vascular smooth muscle. The effect is endothelium-mediated and may vary depending on the agonist studied. The mechanism is uncertain but appears to involve increased nitric oxide (NO) production. Finally, the data suggest that attenuation of contraction may not be due to a direct effect of Hcy but that the compound is modified or acts indirectly in vivo.Key words: nitric oxide, nitric oxide synthase, in vivo, smooth muscle.

Plasma arginine metabolites reflect airway dysfunction in a murine model of allergic airway inflammation

2015 ◽  
Vol 118 (10) ◽  
pp. 1229-1233 ◽  
Author(s):  
Jeremy A. Scott ◽  
Michelle L. North ◽  
Mahrouk Rafii ◽  
Hailu Huang ◽  
Paul Pencharz ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Airway Inflammation ◽  
Plasma Concentrations ◽  
Allergic Airway Inflammation ◽  
Airway Responsiveness ◽  
Arginase Activity ◽  
Therapeutic Interventions ◽  
Oxide Synthase

l-Arginine metabolism is important in the maintenance of airway tone. Shift of metabolism from the nitric oxide synthase to arginase pathways contributes to the increased airway responsiveness in asthma. We tested the hypothesis that systemic levels of l-arginine metabolites are biomarkers reflective of airway dysfunction. We used a mouse model of acute allergic airway inflammation to OVA that manifests with significant airway hyperresponsiveness to methacholine. To determine tissue arginase activity in vivo, the isotopic enrichment of an infused l-arginine stable isotope and its product amino acid l-ornithine were measured in lung and airway homogenates using liquid chromatography-tandem mass spectrometry. Tissue and plasma concentrations of other l-arginine metabolites, including l-citrulline and symmetric and asymmetric dimethylarginine, were measured and correlated with lung arginase activity and methacholine responsiveness of the airways. The effectiveness of intratracheal instillation of an arginase inhibitor (boronoethylcysteine) on pulmonary arginase activity and circulating concentrations of l-arginine metabolites was also studied. We demonstrate that 1) plasma indexes of l-arginine bioavailability and impairment of nitric oxide synthase function correlate with airway responsiveness to methacholine; 2) plasma levels of l-ornithine predict in vivo pulmonary arginase activity and airway function; and 3) acute arginase inhibition reduces in vivo pulmonary arginase activity to control levels and normalizes plasma l-ornithine, but not l-arginine, bioavailability in this model. We conclude that plasma l-ornithine may be useful as a systemic biomarker to predict responses to therapeutic interventions targeting airway arginase in asthma.

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.

Abstract 1333: Modulation Of Cardiac Beta-adrenergic Responsiveness By The Neuronal Nitric Oxide Synthase/Sarcolemmal Calcium Pump Complex

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Tamer M Mohamed ◽  
Delvac Oceandy ◽  
Nasser Alatwi ◽  
Florence Baudoin ◽  
Elizabeth J Cartwright ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Neuronal Nitric Oxide Synthase ◽  
Neonatal Rat ◽  
No Production ◽  
Adrenergic Stimulation ◽  
Rat Cardiomyocytes ◽  
Adrenergic Response ◽  
Oxide Synthase

The pivotal role of neuronal nitric oxide synthase (nNOS) in regulating cardiac function has only recently been unveiled. Notably, others have shown that responsiveness to β-adrenergic stimulation is dependent on nNOS activity. In a cellular model, we showed that the Ca 2+ /calmodulin-dependent nNOS activity is reduced by overexpression of isoform 4b of the plasma membrane Ca 2+ /Calmodulin-dependent Ca 2+ -pump (PMCA4b), which binds to nNOS. We demonstrated that PMCA4b overexpression in the heart reduced β-adrenergic responsiveness in vivo via an nNOS dependent mechanism (Oceandy et al, Circulation 2007). Here we investigated the cellular mechanisms of the regulation of the β-adrenergic response by PMCA4b. We used an adenoviral system to overexpress PMCA4b (PMCA4b cells) or LacZ (control, C) in neonatal rat cardiomyocytes. PMCA4b cells showed an 18±5% and 24±5% reduction in nitric oxide (DAF-FM fluorescence) and cGMP levels, respectively (n=6, p<0.05 each) compared to C demonstrating the regulation of NO production by the PMCA4b in this system. Since nNOS has been shown to regulate phospholamban (PLB) phosphorylation, we examined phosphorylation of PLB at Ser16. PMCA4b cells showed a significant increase in Ser16-PLB at baseline (66±17%, p<0.05) compared to C. As a result of increased baseline Ser16-PLB in PMCA4b cells, β-adrenergic stimulation of PMCA4b cells using 2μM isoproter-enol (IP) showed reduced relative induction in Ser16-PLB (23±10% vs. 78±19% in C; n=5, p<0.05). Further analysis in adult cardiomyocytes isolated from our PMCA4b transgenic mice (PMCA4b TG) demonstrated that PMCA4b TG showed 3-fold higher Ser16-PLB phosphorylation at baseline compared to wild type (WT) myocytes and the relative response following β-adrenergic stimulation was significantly reduced (1.2±0.2 fold induction after IP treatment in PMCA4b TG, vs. 3.1±0.7 in WT, n=5, p<0.05). Thus, PMCA4b regulates NO production from nNOS, which in turn modulates cGMP levels and PLB phosphorylation. These findings provide mechanistic insight into the regulation of the β-adrenergic response in the heart by PMCA4b and place this Ca 2+ -pump upstream of the recently described pathway linking nNOS and Ser16-PLB phosphorylation and downstream of the β-adrenergic receptor(s).

Evaluation of islet heme oxygenase-CO and nitric oxide synthase-NO pathways during acute endotoxemia

2001 ◽  
Vol 280 (5) ◽  
pp. C1242-C1254 ◽  
Author(s):  
Ragnar Henningsson ◽  
Per Alm ◽  
Ingmar Lundquist
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Heme Oxygenase ◽  
Insulin Response ◽  
Glucagon Secretion ◽  
No Production ◽  
Compensatory Mechanisms ◽  
Oxide Synthase

We investigated, by a combined in vivo and in vitro approach, the temporal changes of islet nitric oxide synthase (NOS)-derived nitric oxide (NO) and heme oxygenase (HO)-derived carbon monoxide (CO) production in relation to insulin and glucagon secretion during acute endotoxemia induced by lipopolysaccharide (LPS) in mice. Basal plasma glucagon, islet cAMP and cGMP content after in vitro incubation, the insulin response to glucose in vivo and in vitro, and the insulin and glucagon responses to the adenylate cyclase activator forskolin were greatly increased after LPS. Immunoblots demonstrated expression of inducible NOS (iNOS), inducible HO (HO-1), and an increased expression of constitutive HO (HO-2) in islet tissue. Immunocytochemistry revealed a marked expression of iNOS in many β-cells, but only in single α-cells after LPS. Moreover, biochemical analysis showed a time dependent and markedly increased production of NO and CO in these islets. Addition of a NOS inhibitor to such islets evoked a marked potentiation of glucose-stimulated insulin release. Finally, after incubation in vitro, a marked suppression of NO production by both exogenous CO and glucagon was observed in control islets. This effect occurred independently of a concomitant inhibition of guanylyl cyclase. We suggest that the impairing effect of increased production of islet NO on insulin secretion during acute endotoxemia is antagonized by increased activities of the islet cAMP and HO-CO systems, constituting important compensatory mechanisms against the noxious and diabetogenic actions of NO in endocrine pancreas.

In vivo pharmacological evaluation off two novel type II (inducible) nitric oxide synthase inhibitors

1995 ◽  
Vol 73 (5) ◽  
pp. 665-669 ◽  
Author(s):  
W. Ross Tracey ◽  
Masaki Nakane ◽  
Fatima Basha ◽  
George Carter
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inducible Nitric Oxide Synthase ◽  
No Production ◽  
Type Ii ◽  
Nos Inhibitors ◽  
Oxide Synthase ◽  
Dose Dependent ◽  
Inducible Nitric Oxide

Selective type II (inducible) nitric oxide synthase (NOS) inhibitors have several potential therapeutic applications, including treatment of sepsis, diabetes, and autoimmune diseases. The ability of two novel, selective inhibitors of type II NOS, S-ethylisothiourea (EIT) and 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), to inhibit type II NOS function in vivo was studied in lipopolysaccharide (LPS) treated rats. Type II NOS activity was assessed by measuring changes in plasma nitrite and nitrate concentrations ([NOx]). Both EIT and AMT elicited a dose-dependent and >95% inhibition of the LPS-induced increase in plasma [NOx]. The ED50 values for EIT and AMT were 0.4 and 0.2 mg/kg, respectively. In addition, the administration of LPS and either NOS inhibitor resulted in a dose-dependent increase in animal mortality; neither compound was lethal when administered alone. Pretreatment with L-arginine (but not D-arginine) prevented the mortality, while not affecting the type II NOS-dependent NO production, suggesting the toxicity may be due to inhibition of one of the other NOS isoforms (endothelial or neuronal). Thus, although EIT and AMT are potent inhibitors of type II NOS function in vivo, type II NOS inhibitors of even greater selectivity may need to be developed for therapeutic applications.Key words: nitric oxide, nitrite, nitrate, sepsis, lipopolysaccharide.

scholarly journals Induction of Gamma Interferon and Nitric Oxide by Truncated Pneumolysin That Lacks Pore-Forming Activity

2002 ◽  
Vol 70 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Hisashi Baba ◽  
Ikuo Kawamura ◽  
Chikara Kohda ◽  
Takamasa Nomura ◽  
Yutaka Ito ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Neutralizing Antibody ◽  
Cytolytic Activity ◽  
Gamma Interferon ◽  
Full Length ◽  
No Production ◽  
Spleen Cells ◽  
Ifn Γ ◽  
Oxide Synthase

ABSTRACT Pneumolysin (PLY), an important virulence factor of Streptococcus pneumoniae, is known to exert various effects on the host immune cells, including cytokine induction, in addition to its known cytolytic activity as a member of the thiol-activated cytolysins. It is of interest to determine whether cytolytic activity is involved in triggering the cytokine production. In this study, we constructed full-length recombinant PLY and noncytolytic truncated PLYs with C-terminal deletions to examine the response of spleen cells to these PLY preparations. When cytolytic activity was blocked by treatment with cholesterol, full-length PLY was capable of inducing gamma interferon (IFN-γ) production. Truncated PLYs that originally exhibited no cytolytic activity were also active in IFN-γ induction. Therefore, the IFN-γ-inducing ability of PLY appeared to be independent of the cytolytic activity. Furthermore, IFN-γ-inducing preparations were also capable of inducing nitric oxide synthase expression and nitric oxide (NO) production, and the addition of neutralizing antibody to IFN-γ abolished the NO production. These results clearly demonstrated that PLY is capable of inducing IFN-γ production in spleen cells by a mechanism different from pore formation and that the induced IFN-γ stimulates NO production. These findings were discussed with reference to the contribution of PLY to the virulence of S. pneumoniae in vivo.

scholarly journals Identification of Golgi-localized acyl transferases that palmitoylate and regulate endothelial nitric oxide synthase

2006 ◽  
Vol 174 (3) ◽  
pp. 369-377 ◽  
Author(s):  
Carlos Fernández-Hernando ◽  
Masaki Fukata ◽  
Pascal N. Bernatchez ◽  
Yuko Fukata ◽  
Michelle I. Lin ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Cdna Clones ◽  
No Production ◽  
Human Endothelial Cells ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Lipid modifications mediate the subcellular localization and biological activity of many proteins, including endothelial nitric oxide synthase (eNOS). This enzyme resides on the cytoplasmic aspect of the Golgi apparatus and in caveolae and is dually acylated by both N-myristoylation and S-palmitoylation. Palmitoylation-deficient mutants of eNOS release less nitric oxide (NO). We identify enzymes that palmitoylate eNOS in vivo. Transfection of human embryonic kidney 293 cells with the complementary DNA (cDNA) for eNOS and 23 cDNA clones encoding the Asp-His-His-Cys motif (DHHC) palmitoyl transferase family members showed that five clones (2, 3, 7, 8, and 21) enhanced incorporation of [3H]-palmitate into eNOS. Human endothelial cells express all five of these enzymes, which colocalize with eNOS in the Golgi and plasma membrane and interact with eNOS. Importantly, inhibition of DHHC-21 palmitoyl transferase, but not DHHC-3, in human endothelial cells reduces eNOS palmitoylation, eNOS targeting, and stimulated NO production. Collectively, our data describe five new Golgi-targeted DHHC enzymes in human endothelial cells and suggest a regulatory role of DHHC-21 in governing eNOS localization and function.

scholarly journals Protection against Doxorubicin-Induced Cardiotoxicity through Modulating iNOS/ARG 2 Balance by Electroacupuncture at PC6

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Jingya Wang ◽  
Lin Yao ◽  
Xiaoli Wu ◽  
Qi Guo ◽  
Shengxuan Sun ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Protective Effect ◽  
No Production ◽  
Myocardial Cells ◽  
Molecular Biotechnology ◽  
Underlying Mechanisms ◽  
Vitro Analysis ◽  
Oxide Synthase

Background. Doxorubicin (DOX) is a commonly used chemotherapeutic drug but is limited in clinical applications by its cardiotoxicity. Neiguan acupoint (PC6) is a well-recognized acupoint for the treatment of cardiothoracic disease. However, whether acupuncture at PC6 could be effective in preventing DOX-induced cardiotoxicity is still unknown. Methods. A set of experiments were performed with myocardial cells, wild type, inducible nitric oxide synthase knockout (iNOS-/-), and myocardial-specific ablation arginase 2 (Myh6-ARG 2-/-) mice. We investigated the protective effect and the underlying mechanisms for electroacupuncture (EA) against DOX-induced cardiotoxicity by echocardiography, immunostaining, biochemical analysis, and molecular biotechnology in vivo and in vitro analysis. Results. We found that DOX-mediated nitric oxide (NO) production was positively correlated with the iNOS level but has a negative correlation with the arginase 2 (ARG 2) level in both myocardial cells and tissues. Meanwhile, EA at PC6 alleviated cardiac dysfunction and cardiac hypertrophy in DOX-treated mice. EA at PC6 blocked the upregulation of NO production in accompanied with the downregulated iNOS and upregulated ARG 2 levels in myocardial tissue induced by DOX. Furthermore, knockout iNOS prevented cardiotoxicity and EA treatment did not cause the further improvement of cardiac function in iNOS-/- mice treated by DOX. In contrast, deficiency of myocardial ARG 2 aggravated DOX-induced cardiotoxicity and reduced EA protective effect. Conclusion. These results suggest that EA treatment at PC6 can prevent DOX-induced cardiotoxicity through modulating NO production by modulating the iNOS/ARG 2 balance in myocardial cells.

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