scholarly journals Molecular Characterization and Expression of Cytochrome P450 Aromatase in Atlantic Croaker Brain: Regulation by Antioxidant Status and Nitric Oxide Synthase During Hypoxia Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Md Saydur Rahman ◽  
Peter Thomas
Keyword(s):  
Nitric Oxide ◽  
Cytochrome P450 ◽  
Nitric Oxide Synthase ◽  
Atlantic Croaker ◽  
Mrna Levels ◽  
Hypoxic Stress ◽  
P450 Aromatase ◽  
Cytochrome P450 Aromatase ◽  
Nos Inhibitor ◽  
Oxide Synthase

We have previously shown that nitric oxide synthase (NOS, an enzyme) is significantly increased during hypoxic stress in Atlantic croaker brains and modulated by an antioxidant (AOX). However, the influence of NOS and AOX on cytochrome P450 aromatase (AROM, CYP19a1, an enzyme) activity on vertebrate brains during hypoxic stress is largely unknown. In this study, we characterized brain AROM (bAROM, CYP19a1b) cDNA in croaker and examined the interactive effects of hypoxia and a NOS-inhibitor or AOX on AROM activity. The amino acid sequence of croaker bAROM cDNA is highly homologous (76–80%) to other marine teleost bAROM cDNAs. Both real-time PCR and Northern blot analyses showed that bAROM transcript (size: ∼2.8 kb) is highly expressed in the preoptic-anterior hypothalamus (POAH). Hypoxia exposure (dissolved oxygen, DO: 1.7 mg/L for 4 weeks) caused significant decreases in hypothalamic AROM activity, bAROM mRNA and protein expressions. Hypothalamic AROM activity and mRNA levels were also decreased by pharmacological treatment with N-ethylmaleimide (NEM, an alkylating drug that modifies sulfhydryl groups) of fish exposed to normoxic (DO: ∼6.5 mg/L) conditions. On the other hand, treatments with Nω-nitro-L-arginine methyl ester (NAME, a competitive NOS-inhibitor) or vitamin-E (Vit-E, a powerful AOX) prevented the downregulation of hypothalamic AROM activity and mRNA levels in hypoxic fish. Moreover, NAME and Vit-E treatments also restored gonadal growth in hypoxic fish. Double-labeled immunohistochemistry results showed that AROM and NOS proteins are co-expressed with NADPH oxidase (generates superoxide anion) in the POAH. Collectively, these results suggest that the hypoxia-induced downregulation of AROM activity in teleost brains is influenced by neuronal NOS activity and AOX status. The present study provides, to the best of our knowledge, the first evidence of restoration of AROM levels in vertebrate brains by a competitive NOS-inhibitor and potent AOX during hypoxic stress.

Increasing dihydrobiopterin causes dysfunction of endothelial nitric oxide synthase in rats in vivo

2011 ◽  
Vol 301 (3) ◽  
pp. H721-H729 ◽  
Author(s):  
Katsuhiko Noguchi ◽  
Naobumi Hamadate ◽  
Toshihiro Matsuzaki ◽  
Mayuko Sakanashi ◽  
Junko Nakasone ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Control Treatment ◽  
Enos Uncoupling ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
First Time

An elevation of oxidized forms of tetrahydrobiopterin (BH4), especially dihydrobiopterin (BH2), has been reported in the setting of oxidative stress, such as arteriosclerotic/atherosclerotic disorders, where endothelial nitric oxide synthase (eNOS) is dysfunctional, but the role of BH2 in the regulation of eNOS activity in vivo remains to be evaluated. This study was designed to clarify whether increasing BH2 concentration causes endothelial dysfunction in rats. To increase vascular BH2 levels, the BH2 precursor sepiapterin (SEP) was intravenously given after the administration of the specific dihydrofolate reductase inhibitor methotrexate (MTX) to block intracellular conversion of BH2 to BH4. MTX/SEP treatment did not significantly affect aortic BH4 levels compared with control treatment. However, MTX/SEP treatment markedly augmented aortic BH2 levels (291.1 ± 29.2 vs. 33.4 ± 6.4 pmol/g, P < 0.01) in association with moderate hypertension. Treatment with MTX alone did not significantly alter blood pressure or BH4 levels but decreased the BH4-to-BH2 ratio. Treatment with MTX/SEP, but not with MTX alone, impaired ACh-induced vasodilator and depressor responses compared with the control treatment (both P < 0.05) and also aggravated ACh-induced endothelium-dependent relaxations ( P < 0.05) of isolated aortas without affecting sodium nitroprusside-induced endothelium-independent relaxations. Importantly, MTX/SEP treatment significantly enhanced aortic superoxide production, which was diminished by NOS inhibitor treatment, and the impaired ACh-induced relaxations were reversed with SOD ( P < 0.05), suggesting the involvement of eNOS uncoupling. These results indicate, for the first time, that increasing BH2 causes eNOS dysfunction in vivo even in the absence of BH4 deficiency, demonstrating a novel insight into the regulation of endothelial function.

Glucose uptake during contraction in isolated skeletal muscles from neuronal nitric oxide synthase μ knockout mice

2015 ◽  
Vol 118 (9) ◽  
pp. 1113-1121 ◽  
Author(s):  
Yet Hoi Hong ◽  
Tony Frugier ◽  
Xinmei Zhang ◽  
Robyn M. Murphy ◽  
Gordon S. Lynch ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Nitric Oxide Synthase ◽  
Glucose Uptake ◽  
Ex Vivo ◽  
Organ Bath ◽  
Skeletal Muscle Glucose Uptake ◽  
Nos Inhibitor ◽  
Amp Activated Protein Kinase ◽  
Oxide Synthase

Inhibition of nitric oxide synthase (NOS) significantly attenuates the increase in skeletal muscle glucose uptake during contraction/exercise, and a greater attenuation is observed in individuals with Type 2 diabetes compared with healthy individuals. Therefore, NO appears to play an important role in mediating muscle glucose uptake during contraction. In this study, we investigated the involvement of neuronal NOSμ (nNOSμ), the main NOS isoform activated during contraction, on skeletal muscle glucose uptake during ex vivo contraction. Extensor digitorum longus muscles were isolated from nNOSμ−/−and nNOSμ+/+mice. Muscles were contracted ex vivo in a temperature-controlled (30°C) organ bath with or without the presence of the NOS inhibitor NG-monomethyl-l-arginine (L-NMMA) and the NOS substrate L-arginine. Glucose uptake was determined by radioactive tracers. Skeletal muscle glucose uptake increased approximately fourfold during contraction in muscles from both nNOSμ−/−and nNOSμ+/+mice. L-NMMA significantly attenuated the increase in muscle glucose uptake during contraction in both genotypes. This attenuation was reversed by L-arginine, suggesting that L-NMMA attenuated the increase in muscle glucose uptake during contraction by inhibiting NOS and not via a nonspecific effect of the inhibitor. Low levels of NOS activity (∼4%) were detected in muscles from nNOSμ−/−mice, and there was no evidence of compensation from other NOS isoform or AMP-activated protein kinase which is also involved in mediating muscle glucose uptake during contraction. These results indicate that NO regulates skeletal muscle glucose uptake during ex vivo contraction independently of nNOSμ.

Human placental and fetal membrane nitric oxide synthase activity before, during and after labour at term

1995 ◽  
Vol 7 (6) ◽  
pp. 1505 ◽  
Author(s):  
Iulio JL Di ◽  
NM Gude ◽  
RG King ◽  
SP Brennecke
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Caesarean Section ◽  
Normal Vaginal Delivery ◽  
Fetal Membrane ◽  
High Concentration ◽  
Experimental Conditions ◽  
Nos Inhibitor ◽  
Tissue Specimens ◽  
Oxide Synthase

The aim of this study was to determine whether any labour-associated changes in nitric oxide synthase (NOS) activity occur in human placenta and fetal membranes. NOS activity in amnion, choriodecidua, and placenta obtained from women before (at Caesarean section, not in labour), during (at Caesarean section, in labour) and after (spontaneous onset labour, normal vaginal delivery) labour was assessed by measuring conversion of radio-labelled L-arginine to L-citrulline. NOS activity, as judged by its inhibition by the specific NOS inhibitor N omega-nitro-L-arginine, was present in placental and amnionic tissues, but not in choriodecidual tissue specimens. Activity detected in choriodecidua was significantly blocked during incubation with a high concentration of valine, suggesting that L-arginine was being consumed by reactions other than NOS under the experimental conditions in that tissue. There were no significant differences among the labour groups in either amnion or placental NOS activities measured in the presence of 1 microM L-arginine. Amnion NOS activity was significantly less than that in placenta. Placental V(max) and Km values (determined after removal of endogenous L-arginine) did not differ significantly among the different labour groups.

Requirement of nuclear factor kappaB for the constitutive expression of nitric oxide synthase-2 and cyclooxygenase-2 in rat trophoblasts

1999 ◽  
Vol 112 (18) ◽  
pp. 3147-3155
Author(s):  
N.A. Callejas ◽  
M. Casado ◽  
L. Bosca ◽  
P. Martin-Sanz
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Cyclooxygenase 2 ◽  
Nuclear Factor Kappab ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Cox 2 ◽  
Nf Kappab ◽  
Nitric Oxide Synthase 2 ◽  
Oxide Synthase

Recently isolated trophoblasts express nitric oxide synthase 2 (NOS-2) and cyclooxygenase 2 (COX-2), decreasing the levels of the corresponding mRNAs when the cells were maintained in culture. The sustained expression of COX-2 and NOS-2 in trophoblasts was dependent on the activation of nuclear factor kappaB (NF-kappaB) since proteasome inhibitors and antioxidants that abrogated NF-kappaB activity suppressed the induction of both genes. The time-dependent fall of the mRNA levels of NOS-2 and COX-2 paralleled the inhibition of NF-kappaB, determined by electrophoretic mobility shift assays, and the increase of the IkappaBalpha and IkappaBbeta inhibitory proteins. Isolated trophoblasts synthesized reactive oxygen intermediates (ROI), a process impaired after culturing the cells, and that might be involved in the NF-kappaB activation process. Moreover, treatment of recently isolated cells with ROI scavengers suppressed the expression of COX-2 and NOS-2. Challenge of trophoblasts with interleukin-1beta up-regulated the expression of both proteins, an effect that was potentiated by lipopolysaccharide. These results indicate that the physiological expression of NOS-2 and COX-2 in trophoblasts involves a sustained activation of NF-kappaB which inhibition abrogates the inducibility of both genes.

scholarly journals Formation of Transient Oxygen Complexes of Cytochrome P450 BM3 and Nitric Oxide Synthase under High Pressure

2003 ◽  
Vol 85 (5) ◽  
pp. 3303-3309 ◽  
Author(s):  
Stéphane Marchal ◽  
Hazel Mary Girvan ◽  
Antonius C.F. Gorren ◽  
Bernd Mayer ◽  
Andrew William Munro ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
High Pressure ◽  
Cytochrome P450 ◽  
Nitric Oxide Synthase ◽  
P450 Bm3 ◽  
Cytochrome P450 Bm3 ◽  
Oxide Synthase ◽  
Oxygen Complexes

PKC mediates LPS- and phorbol-induced cardiac cell nitric oxide synthase activity and hypocontractility

1995 ◽  
Vol 269 (6) ◽  
pp. H1891-H1898 ◽  
Author(s):  
T. M. McKenna ◽  
S. Li ◽  
S. Tao
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Cardiac Myocyte ◽  
Contractile Function ◽  
Dependent Manner ◽  
Cardiac Cell ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Myocyte Contractility ◽  
Rat Cardiac Myocytes

Lipopolysaccharide (LPS) treatment impairs cardiac myocyte contractility in a nitric oxide synthase (NOS)-dependent manner. The objective of this study was to assess whether protein kinase C (PKC) transduces the LPS signal into an enhanced NOS activity in rat cardiac myocytes. LPS (100 ng/ml) stimulated myocyte PKC activity, inducible NOS (iNOS) expression, and NOS activity in a time- and protein synthesis-dependent fashion. Directly activating PKC with beta-phorbol 12,13-dibutyrate (beta-PDB) also induced myocyte iNOS synthesis and NOS activity and reduced electrically stimulated contractility, while the inactive alpha-PDB was ineffectual. Contractility could be restored to beta-PDB-incubated cells by superfusion with the NOS inhibitor N omega-nitro-L-arginine methyl ester. PKC blockade with sphingosine, chelerythrine, or calphostin-C precluded LPS- and beta-PDB-induced increases in NOS activity and protected contractility. Depletion of PKC by 18 h of incubation with beta-PDB in the presence of chelerythrine also blocked acquisition of enhanced NOS activity and contractile dysfunction when the myocytes were subsequently exposed to LPS. These findings suggest that PKC is a significant intracellular mediator for the effects of LPS on cardiac cell NOS activity and contractile function.

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