Specific effect of arachidonic acid on inducible nitric oxide synthase mRNA expression in human osteoblastic cells

2005 ◽  
Vol 109 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Giovanna Priante ◽  
Estella Musacchio ◽  
Elisa Pagnin ◽  
Lorenzo A. Calò ◽  
Bruno Baggio
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Arachidonic Acid ◽  
Mrna Expression ◽  
Inos Expression ◽  
Osteoblastic Cells ◽  
Human Osteoblast ◽  
Inos Gene ◽  
Human Osteoblastic Cells ◽  
Inos Gene Expression

A specific modulatory effect of PUFAs (polyunsaturated fatty acids) on gene expression of some cytokines involved in bone remodelling has been reported previously. In particular, although a direct action of AA (arachidonic acid) on bone cytokine gene expression has been shown in human osteoblastic cells, OA (oleic acid) and EPA (eicosapentaenoic acid) were ineffective. Since the NO (nitric oxide) system has also been shown to have an important modulatory activity on osteoblasts, osteoclasts and bone metabolism, in the present study we have investigated the effects of PUFAs on iNOS (inducible NO synthase) gene expression in a human osteoblast-like cell line. AA induced a significant increase in iNOS mRNA expression, whereas EPA and OA had no stimulatory effects but instead caused a significant inhibition of AA-induced iNOS gene expression. Blocking of the COX (cyclo-oxygenase) pathway did not inhibit AA-induced iNOS expression. AA action was inhibited instead by the addition of calphostin C and genistein, inhibitors of PKC (protein kinase C) and tyrosine kinases respectively. Experiments performed with specific anti-cytokine antibodies showed a significant decrease in iNOS expression in AA-treated osteoblastic cells, suggesting that both cytokine-dependent and -independent mechanisms account for the effects of AA on iNOS gene expression. In conclusion, our investigation clearly shows specific effects of PUFAs on iNOS expression in human osteoblast-like cells with a cytokine-dependent and -independent mechanism. These results might have clinical relevance and are of interest for understanding the reported beneficial effects of dietary PUFA manipulation on the prevention and/or treatment of primary and secondary bone disease.

scholarly journals Essential amino acid tryptophan inhibits induction of inducible nitric oxide synthase gene expression in interleukin-1β stimulated hepatocytes

2019 ◽  
Vol 2 (7) ◽  
pp. 170
Author(s):  
Takumi Tsuda ◽  
Hirokazu Miki ◽  
Richi Nakatake ◽  
Tatsuma Sakaguchi ◽  
Masahiko Hatta ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inducible Nitric Oxide Synthase ◽  
Inos Expression ◽  
No Production ◽  
Inos Gene ◽  
Oxide Synthase ◽  
Inos Gene Expression ◽  
Inducible Nitric Oxide

Background/objective: Tryptophan exerts protective effects against a variety of organ inflammation and injury, including liver. However, there are few scientific reports about the mechanisms involved in the action. Pro-inflammatory cytokine interleukin (IL)-1β stimulates the induction of inducible nitric oxide synthase (iNOS) expression and NO production in cultured hepatocytes (“in vitro liver injury model”), and the prevention of iNOS expression and NO production is considered to be an indicator of liver protection. This study aimed to examine whether tryptophan influences the induction of iNOS gene expression and the mechanisms.Methods: Tryptophan was added into primary cultures of rat hepatocytes stimulated by IL-1β. The iNOS induction, NO production and its signaling pathway were analyzed.Results: IL-1β induced iNOS gene expression, which was followed by iNOS expression and NO production. Tryptophan inhibited the expression of iNOS mRNA and protein, and decreased the production of NO. Transfection experiments with iNOS promoter-luciferase constructs revealed that tryptophan reduced the activities of iNOS mRNA synthesis and its stability. Tryptophan blocked two essential signaling pathways, the activation of nuclear factor (NF)-κB and upregulation of type I IL-1receptor (IL-1RI).Conclusions: Results indicate that tryptophan can prevent the NO production by the inhibition of iNOS gene expression, in part through NF-κB activation and IL-1RI upregulation, in inflamed hepatocytes. Tryptophan may be a potential therapeutic treatment in injured organs, including liver.Key words: tryptophan, inducible nitric oxide synthase, nitric oxide, cultured hepatocytes, nuclear factor-κB, type I interleukin-1 receptor

PPARγ is not required for the inhibitory actions of PGJ2 on cytokine signaling in pancreatic β-cells

2004 ◽  
Vol 286 (3) ◽  
pp. E329-E336 ◽  
Author(s):  
Sarah M. Weber ◽  
Anna L. Scarim ◽  
John A. Corbett
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Cytokine Signaling ◽  
Rinm5f Cells ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Inos Gene ◽  
Ifn Γ ◽  
Anti Inflammatory ◽  
Inos Gene Expression

Peroxisome proliferator-activated receptor (PPAR)γ agonists, such as 15-deoxy-Δ12,14-prostaglandin J2 (PGJ2) and troglitazone, have been shown to elicit anti-inflammatory effects in pancreatic β-cells that include inhibition of cytokine-stimulated inducible nitric oxide synthase (iNOS) gene expression and production of nitric oxide. In addition, these ligands impair IL-1-induced NF-κB and MAPK as well as IFN-γ-stimulated signal transducer and activator of transcription (STAT)1 activation in β-cells. The purpose of this study was to determine if PPARγ activation participates in the anti-inflammatory actions of PGJ2 in β-cells. Pretreatment of RINm5F cells for 6 h with PGJ2 results in inhibition of IL-1-stimulated IκB degradation and IFN-γ-stimulated STAT1 phosphorylation. Overexpression of a dominant-negative (dn) PPARγ mutant or treatment with the PPARγ antagonist GW-9662 does not modulate the inhibitory actions of PGJ2 on cytokine signaling in RINm5F cells. Although these agents fail to attenuate the inhibitory actions of PGJ2 on cytokine signaling, they do inhibit PGJ2-stimulated PPARγ response element reporter activity. Consistent with the inability to attenuate the inhibitory actions of PGJ2 on cytokine signaling, neither dnPPARγ nor GW-9662 prevents the inhibitory actions of PGJ2 on IL-1-stimulated iNOS gene expression or nitric oxide production by RINm5F cells. These findings support a PPARγ-independent mechanism by which PPARγ ligands impair cytokine signaling and iNOS expression by islets.

scholarly journals Effects of Lycopene, Indole-3-Carbinol, and Luteolin on Nitric Oxide Production and iNOS Expression are Organ-Specific in Rats

2010 ◽  
Vol 61 (3) ◽  
pp. 275-285 ◽  
Author(s):  
Evita Rostoka ◽  
Sergejs Isajevs ◽  
Larisa Baumane ◽  
Aija Line ◽  
Karina Silina ◽  
...  
Keyword(s):  
Gene Expression ◽  
Brain Cortex ◽  
Natural Compounds ◽  
Inos Expression ◽  
No Production ◽  
Nitric Oxide Production ◽  
Inos Gene ◽  
Organ Specific ◽  
The Brain ◽  
Inos Gene Expression

Effects of Lycopene, Indole-3-Carbinol, and Luteolin on Nitric Oxide Production and iNOS Expression are Organ-Specific in RatsNatural compounds are known to modify NO content in tissues; however, the biological activity of polyphenol-rich food often does not correspond to the effects of individual polyphenols on NO synthase activity. The aim of this study was to see how natural compounds luteolin, indole-3-carbinol, and lycopene modify NO production in rat tissues and change the expression of the iNOS gene and protein. Indole-3-carbinol produced multiple effects on the NO level; it significantly decreased NO concentration in blood, lungs, and skeletal muscles and increased it in the liver. Indole-3-carbinol enhanced lipopolyssaccharide (LPS)-induced NO production in all rat organs. It decreased iNOS gene expression in the brain cortex of animals that did not receive LPS and up-regulated it in the LPS-treated animals. Lycopene increased the iNOS gene transcription rate in the brain cortex of LPS-treated animals. Luteolin did not modify NO production in any organ of LPS-untreated rats, nor did it affect gene expression in the liver. In the brain it slightly decreased iNOS gene expression. Luteolin decreased NO production in the blood of LPS-treated animals and the number of iNOS-positive cells in these animals. Our results suggest that changes in tissue NO levels caused by natural compounds cannot be predicted from their effect on NOS expression or activity obtained in model systems. This stresses the importance of direct measurements of NO and NOS expression in animal tissues.

scholarly journals Role of Nuclear Factor-κB Activation in Cytokine- and Sphingomyelinase-Stimulated Inducible Nitric Oxide Synthase Gene Expression in Vascular Smooth Muscle Cells**This work was supported in part by grants-in-aid from the Ministry of Education, Science, and Culture and the Ministry of Health and Welfare of Japan.

Endocrinology ◽  
1998 ◽  
Vol 139 (11) ◽  
pp. 4506-4512 ◽  
Author(s):  
Koichi Katsuyama ◽  
Masayoshi Shichiri ◽  
Fumiaki Marumo ◽  
Yukio Hirata
Keyword(s):  
Gene Expression ◽  
Nuclear Translocation ◽  
Proteasome Inhibitors ◽  
Nuclear Factor Κb ◽  
Inos Expression ◽  
Inos Gene ◽  
Oxide Synthase ◽  
Inos Gene Expression ◽  
Inducible Nitric Oxide

Abstract Inflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNFα), are known to activate sphingomyelinase (SMase) and nuclear factor-κB (NF-κB) in certain cell types, which also stimulate inducible nitric oxide synthase (iNOS) gene in vascular smooth muscle cells (VSMCs). However, it remains unknown whether the SMase pathway is involved in iNOS gene expression in VSMCs. Therefore, the present study was designed to examine whether SMase induces iNOS gene expression via the NF-κB activation pathway similar to that of IL-1β and TNFα in cultured rat VSMCs. Neutral SMase, although less potently than IL-1β and TNFα, stimulated nitrite/nitrate (NOx) production, and iNOS messenger RNA and protein expression, as assessed by Northern and Western blot analyses, respectively. Neutral SMase, IL-1β, and TNFα activated NF-κB, as revealed by electrophoretic mobility shift assay, and its nuclear translocation, as demonstrated by immunocytochemical study. Neutral SMase potentiated NOx production, iNOS expression, and NF-κB activation stimulated by TNFα, but not by IL-1β. Aldehyde peptide proteasome inhibitors completely blocked NOx production, iNOS expression, NF-κB activation, and its nuclear translocation induced by cytokines and neutral SMase. IL-1β and TNFα, but not neutral SMase, caused a transient decrease in IκB-α protein levels, whereas IκB-β protein expression was not affected by either agent. Proteasome inhibitors prevented cytokine-mediated IκB-α degradation. Several cell-permeable ceramide analogs (C2, C6, and C8), hydrolysis products of sphingomyelin, activated NF-κB less potently than neutral SMase, but had no effect on NOx production. These results demonstrate an essential role of NF-κB activation in mediation of neutral SMase-induced iNOS expression, but distinct from the proteasome-mediated IκB-α degradation by cytokines, suggesting the possible involvement of an additional signaling pathway(s).

Dexamethasone suppresses iNOS gene expression by upregulating I-κBα and inhibiting NF-κB

1997 ◽  
Vol 273 (6) ◽  
pp. G1290-G1296 ◽  
Author(s):  
Michael E. De Vera ◽  
Bradley S. Taylor ◽  
Qi Wang ◽  
Richard A. Shapiro ◽  
Timothy R. Billiar ◽  
...  
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Rat Hepatocytes ◽  
Nuclear Factor Κb ◽  
Interferon Γ ◽  
Inos Expression ◽  
Inos Mrna ◽  
Band Shift ◽  
Inos Gene ◽  
Inos Gene Expression

Cytokine-stimulated inducible nitric oxide synthase (iNOS) gene expression is dependent on nuclear factor-κB (NF-κB) activation and is suppressed by glucocorticoids (GC). In this study we examined the molecular mechanisms of GC inhibition of iNOS expression in rat hepatocytes. Combinations of tumor necrosis factor-α, interleukin-1β, and interferon-γ (cytokine mixture CM) induced high levels of iNOS mRNA and NO synthesis. The synthetic GC dexamethasone markedly repressed iNOS mRNA and protein expression, and nuclear run-on assays showed that this inhibition was occurring at the level of transcription. In addition, transfection studies showed that CM-stimulated activity of a 1.6-kb murine iNOS promoter fragment linked upstream of luciferase was suppressed by dexamethasone. Electromobility shift assays demonstrated that CM induced the appearance of an NF-κB complex composed of p50 and p65 subunits; the addition of dexamethasone markedly decreased this band shift. I-κBα expression was decreased by CM and upregulated in the presence of dexamethasone. Subsequently, nuclear p65 levels were decreased by dexamethasone compared with CM-treated cells. Thus GC repress NF-κB DNA-binding activity in rat hepatocytes in part through the upregulation of its inhibitor I-κBα. These data indicate that one mechanism by which GC block iNOS expression is through the inhibition of NF-κB activation resulting in decreased iNOS transcription.

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