scholarly journals Prolactin activation of mammary nitric oxide synthase: molecular mechanisms

2002 ◽  
Vol 28 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase ◽  
Intracellular Calcium ◽  
Molecular Mechanisms ◽  
Mammary Epithelial Cells ◽  
Calcium Ionophore ◽  
Mammary Epithelial ◽  
No Production ◽  
2B Protein ◽  
Oxide Synthase

Prolactin (PRL) is capable of stimulating both calcium and nitric oxide (NO) accumulation in mammary epithelial cells within 15min. A calcium ionophore was also able to stimulate NO levels to an extent similar to that generated by PRL. Furthermore, maximal concentrations of PRL and the ionophore were not additive, suggesting that they were both using the same pathway, i.e. calcium. Finally, the depletion of intracellular calcium completely abrogated the effect of PRL on NO production. No other pathway known to affect NO synthase (NOS) influenced the action of PRL. Specifically, manipulations of protein phosphatase 2B, protein kinase B (PKB), protein kinase C (PKC), and arginine transport did not alter the activation of NOS by PRL. Therefore, the ability of PRL to stimulate NO production at 15min can be completely explained by its ability to elevate intracellular calcium.

scholarly journals Interaction of PKC and NOS in signal transduction of microvascular hyperpermeability

1997 ◽  
Vol 273 (5) ◽  
pp. H2442-H2451 ◽  
Author(s):  
Qiaobing Huang ◽  
Yuan Yuan
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase ◽  
Calcium Ionophore ◽  
Cytosolic Calcium ◽  
No Production ◽  
Apparent Permeability ◽  
Apparent Permeability Coefficient ◽  
Dependent Protein ◽  
Transient Elevation ◽  
Oxide Synthase

Our previous studies have shown that inflammatory mediators increase microvascular permeability through a phospholipase C-nitric oxide synthase (NOS)-guanylate cyclase cascade. The aim of this study is to delineate in more detail the signaling pathway leading to microvascular hyperpermeability. Endothelial cytosolic calcium and the apparent permeability coefficient of albumin ( P a) were measured in isolated and perfused coronary venules. Histamine stimulated a rapid increase in cytosolic calcium followed by a transient elevation in P a. The NOS inhibitor N G-monomethyl-l-arginine (l-NMMA) and the guanosine 3′,5′-cyclic monophosphate-dependent protein kinase G (PKG) inhibitor KT-5823 abolished the hyperpermeability but did not affect the calcium response to histamine. Similarly, the calcium ionophore ionomycin produced a calcium spike preceding venular hyperpermeability. Blockage of the NOS-PKG cascade inhibited the increase in P a, whereas the endothelial calcium was still elevated on administration of ionomycin. Furthermore, the relationship between protein kinase C (PKC) and the calcium-NOS-PKG pathway in modulation of venular permeability was investigated. Stimulation of PKC with phorbol 12-myristate 13-acetate (PMA) dramatically increased basal P a without significantly changing the cytosolic calcium level. The selective PKC inhibitor bisindolylmaleimide abolished the effect of PMA but did not alter the effect of histamines on P a. In contrast, both l-NMMA and KT-5823 were able to greatly attenuate the increase in P a caused by PMA. These results suggest that 1) elevation of endothelial cytosolic calcium is an early signaling event preceding nitric oxide (NO) synthesis in the transduction of endothelial hyperpermeability, and 2) activation of PKC may alter the endothelial barrier function partially through the modulation of NO production.

The Signaling Pathways in Nitric Oxide Production by Neutrophils Exposed to N-nitrosodimethylamine

2018 ◽  
Vol 16 (2) ◽  
pp. 194-199
Author(s):  
Wioletta Ratajczak-Wrona ◽  
Ewa Jablonska
Keyword(s):  
Nitric Oxide ◽  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Polymorphonuclear Neutrophils ◽  
Microbial Pathogens ◽  
Human Neutrophils ◽  
No Production ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

Background: Polymorphonuclear neutrophils (PMNs) play a crucial role in the innate immune system’s response to microbial pathogens through the release of reactive nitrogen species, including Nitric Oxide (NO). </P><P> Methods: In neutrophils, NO is produced by the inducible Nitric Oxide Synthase (iNOS), which is regulated by various signaling pathways and transcription factors. N-nitrosodimethylamine (NDMA), a potential human carcinogen, affects immune cells. NDMA plays a major part in the growing incidence of cancers. Thanks to the increasing knowledge on the toxicological role of NDMA, the environmental factors that condition the exposure to this compound, especially its precursors- nitrates arouse wide concern. Results: In this article, we present a detailed summary of the molecular mechanisms of NDMA’s effect on the iNOS-dependent NO production in human neutrophils. Conclusion: This research contributes to a more complete understanding of the mechanisms that explain the changes that occur during nonspecific cellular responses to NDMA toxicity.

Hypothermia-induced cardioprotection using extended ischemia and early reperfusion cooling

2007 ◽  
Vol 292 (4) ◽  
pp. H1995-H2003 ◽  
Author(s):  
Zuo-Hui Shao ◽  
Wei-Tien Chang ◽  
Kim Chai Chan ◽  
Kim R. Wojcik ◽  
Chin-Wang Hsu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase ◽  
Therapeutic Hypothermia ◽  
Optimal Timing ◽  
No Production ◽  
Early Reperfusion ◽  
No Signaling ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Pkc Activation

Optimal timing of therapeutic hypothermia for cardiac ischemia is unknown. Our prior work suggests that ischemia with rapid reperfusion (I/R) in cardiomyocytes can be more damaging than prolonged ischemia alone. Also, these cardiomyocytes demonstrate protein kinase C (PKC) activation and nitric oxide (NO) signaling that confer protection against I/R injury. Thus we hypothesized that hypothermia will protect most using extended ischemia and early reperfusion cooling and is mediated via PKC and NO synthase (NOS). Chick cardiomyocytes were exposed to an established model of 1-h ischemia/3-h reperfusion, and the same field of initially contracting cells was monitored for viability and NO generation. Normothermic I/R resulted in 49.7 ± 3.4% cell death. Hypothermia induction to 25°C was most protective (14.3 ± 0.6% death, P < 0.001 vs. I/R control) when instituted during extended ischemia and early reperfusion, compared with induction after reperfusion (22.4 ± 2.9% death). Protection was completely lost if onset of cooling was delayed by 15 min of reperfusion (45.0 ± 8.2% death). Extended ischemia/early reperfusion cooling was associated with increased and sustained NO generation at reperfusion and decreased caspase-3 activation. The NOS inhibitor Nω-nitro-l-arginine methyl ester (200 μM) reversed these changes and abrogated hypothermia protection. In addition, the PKCε inhibitor myr-PKCε v1-2 (5 μM) also reversed NO production and hypothermia protection. In conclusion, therapeutic hypothermia initiated during extended ischemia/early reperfusion optimally protects cardiomyocytes from I/R injury. Such protection appears to be mediated by increased NO generation via activation of protein kinase Cε; nitric oxide synthase.

Effects of homocysteine on endothelial nitric oxide production

2000 ◽  
Vol 279 (4) ◽  
pp. F671-F678 ◽  
Author(s):  
Xiaohui Zhang ◽  
Hong Li ◽  
Haoli Jin ◽  
Zachary Ebin ◽  
Sergey Brodsky ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Redox State ◽  
Calcium Ionophore ◽  
No Production ◽  
Cellular Redox ◽  
A Cell ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Peroxynitrite Scavengers

Hyperhomocysteinemia (HHCy) is an independent and graded cardiovascular risk factor. HHCy is prevalent in patients with chronic renal failure, contributing to the increased mortality rate. Controversy exists as to the effects of HHCy on nitric oxide (NO) production: it has been shown that HHCy both increases and suppresses it. We addressed this problem by using amperometric electrochemical NO detection with a porphyrinic microelectrode to study responses of endothelial cells incubated with homocysteine (Hcy) to the stimulation with bradykinin, calcium ionophore, or l-arginine. Twenty-four-hour preincubation with Hcy (10, 20, and 50 μM) resulted in a gradual decline in responsiveness of endothelial cells to the above stimuli. Hcy did not affect the expression of endothelial nitric oxide synthase (eNOS), but it stimulated formation of superoxide anions, as judged by fluorescence of dichlorofluorescein, and peroxynitrite, as detected by using immunoprecipitation and immunoblotting of proteins modified by tyrosine nitration. Hcy did not directly affect the ability of recombinant eNOS to generate NO, but oxidation of sulfhydryl groups in eNOS reduced its NO-generating activity. Addition of 5-methyltetrahydrofolate restored NO responses to all agonists tested but affected neither the expression of the enzyme nor formation of nitrotyrosine-modified proteins. In addition, a scavenger of peroxynitrite or a cell-permeant superoxide dismutase mimetic reversed the Hcy-induced suppression of NO production by endothelial cells. In conclusion, electrochemical detection of NO release from cultured endothelial cells demonstrated that concentrations of Hcy >20 μM produce a significant indirect suppression of eNOS activity without any discernible effects on its expression. Folates, superoxide ions, and peroxynitrite scavengers restore the NO-generating activity to eNOS, collectively suggesting that cellular redox state plays an important role in HCy-suppressed NO-generating function of this enzyme.

scholarly journals Endoplasmic Reticulum Ca2+ Release Modulates Endothelial Nitric-oxide Synthase via Extracellular Signal-regulated Kinase (ERK) 1/2-mediated Serine 635 Phosphorylation

2011 ◽  
Vol 286 (22) ◽  
pp. 20100-20108 ◽  
Author(s):  
Zhihong Xiao ◽  
Tingting Wang ◽  
Honghua Qin ◽  
Chao Huang ◽  
Youmei Feng ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Protein Kinase ◽  
Nitric Oxide Synthase ◽  
Protein Phosphorylation ◽  
Endothelial Nitric Oxide Synthase ◽  
No Production ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Endothelial nitric-oxide synthase (eNOS) plays a central role in cardiovascular regulation. eNOS function is critically modulated by Ca2+ and protein phosphorylation, but the interrelationship between intracellular Ca2+ mobilization and eNOS phosphorylation is poorly understood. Here we show that endoplasmic reticulum (ER) Ca2+ release activates eNOS by selectively promoting its Ser-635/633 (bovine/human) phosphorylation. With bovine endothelial cells, thapsigargin-induced ER Ca2+ release caused a dose-dependent increase in eNOS Ser-635 phosphorylation, leading to elevated NO production. ER Ca2+ release also promoted eNOS Ser-633 phosphorylation in mouse vessels in vivo. This effect was independent of extracellular Ca2+ and selective to Ser-635 because the phosphorylation status of other eNOS sites, including Ser-1179 or Thr-497, was unaffected in thapsigargin-treated cells. Blocking ERK1/2 abolished ER Ca2+ release-induced eNOS Ser-635 phosphorylation, whereas inhibiting protein kinase A or Ca2+/calmodulin-dependent protein kinase II had no effect. Protein phosphorylation assay confirmed that ERK1/2 directly phosphorylated the eNOS Ser-635 residue in vitro. Further studies demonstrated that ER Ca2+ release-induced ERK1/2 activation mediated the enhancing action of purine or bradykinin receptor stimulation on eNOS Ser-635/633 phosphorylation in bovine/human endothelial cells. Mutating the Ser-635 to nonphosphorylatable alanine prevented ATP from activating eNOS in cells. Taken together, these studies reveal that ER Ca2+ release enhances eNOS Ser-635 phosphorylation and function via ERK1/2 activation. Because ER Ca2+ is commonly mobilized by agonists or physicochemical stimuli, the identified ER Ca2+-ERK1/2-eNOS Ser-635 phosphorylation pathway may have a broad role in the regulation of endothelial function.

scholarly journals Dual modes of control of c-fos mRNA induction by intracellular calcium in T cells.

1994 ◽  
Vol 14 (7) ◽  
pp. 4579-4587 ◽  
Author(s):  
G Lee ◽  
M Gilman
Keyword(s):  
T Cells ◽  
Protein Kinase C ◽  
T Cell ◽  
Protein Kinase ◽  
Intracellular Calcium ◽  
Molecular Mechanisms ◽  
Calcium Ionophore ◽  
Cytoplasmic Calcium ◽  
Mrna Induction ◽  
Kinase C

Cytoplasmic calcium is a nearly universal second messenger in eukaryotes. In many cell types, elevated intracellular calcium interacts synergistically with inducers of protein kinase C to elicit activation of complete biological programs normally induced by extracellular signals. In T cells, elevated cytoplasmic calcium is a critical mediator of activation in response to stimulation of the antigen receptor, and in some T-cell lines, treatment with a combination of calcium ionophore and protein kinase C activator mimics authentic antigen treatment. The synergistic interaction of calcium and protein kinase C in T cells is also observed at the level of gene expression. Here we examine the molecular mechanisms through which these agents exert synergistic control over the expression of the c-fos proto-oncogene in a T-cell hybridoma. We find that the principal effect of calcium is on the elongation of c-fos transcripts. This step constitutes the major control of c-fos mRNA accumulation in these cells. In addition, calcium regulates the initiation of c-fos transcription. This effect requires the serum response element of the c-fos gene and an additional sequence immediately 3' to this element. Thus, calcium regulates c-fos expression through at least two distinct molecular pathways.

Dual modes of control of c-fos mRNA induction by intracellular calcium in T cells

1994 ◽  
Vol 14 (7) ◽  
pp. 4579-4587
Author(s):  
G Lee ◽  
M Gilman
Keyword(s):  
T Cells ◽  
Protein Kinase C ◽  
T Cell ◽  
Protein Kinase ◽  
Intracellular Calcium ◽  
Molecular Mechanisms ◽  
Calcium Ionophore ◽  
Cytoplasmic Calcium ◽  
Mrna Induction ◽  
Kinase C

Cytoplasmic calcium is a nearly universal second messenger in eukaryotes. In many cell types, elevated intracellular calcium interacts synergistically with inducers of protein kinase C to elicit activation of complete biological programs normally induced by extracellular signals. In T cells, elevated cytoplasmic calcium is a critical mediator of activation in response to stimulation of the antigen receptor, and in some T-cell lines, treatment with a combination of calcium ionophore and protein kinase C activator mimics authentic antigen treatment. The synergistic interaction of calcium and protein kinase C in T cells is also observed at the level of gene expression. Here we examine the molecular mechanisms through which these agents exert synergistic control over the expression of the c-fos proto-oncogene in a T-cell hybridoma. We find that the principal effect of calcium is on the elongation of c-fos transcripts. This step constitutes the major control of c-fos mRNA accumulation in these cells. In addition, calcium regulates the initiation of c-fos transcription. This effect requires the serum response element of the c-fos gene and an additional sequence immediately 3' to this element. Thus, calcium regulates c-fos expression through at least two distinct molecular pathways.

Flow-dependent regulation of endothelial nitric oxide synthase: role of protein kinases

2003 ◽  
Vol 285 (3) ◽  
pp. C499-C508 ◽  
Author(s):  
Yong Chool Boo ◽  
Hanjoong Jo
Keyword(s):  
Nitric Oxide ◽  
Shear Stress ◽  
Protein Kinase ◽  
Nitric Oxide Synthase ◽  
Protein Kinases ◽  
Endothelial Nitric Oxide Synthase ◽  
Current Status ◽  
No Production ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Vascular endothelial cells are directly and continuously exposed to fluid shear stress generated by blood flow. Shear stress regulates endothelial structure and function by controlling expression of mechanosensitive genes and production of vasoactive factors such as nitric oxide (NO). Though it is well known that shear stress stimulates NO production from endothelial nitric oxide synthase (eNOS), the underlying molecular mechanisms remain unclear and controversial. Shear-induced production of NO involves Ca2+/calmodulin-independent mechanisms, including phosphorylation of eNOS at several sites and its interaction with other proteins, including caveolin and heat shock protein-90. There have been conflicting results as to which protein kinases—protein kinase A, protein kinase B (Akt), other Ser/Thr protein kinases, or tyrosine kinases—are responsible for shear-dependent eNOS regulation. The functional significance of each phosphorylation site is still unclear. We have attempted to summarize the current status of understanding in shear-dependent eNOS regulation.

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.

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 &micro;g 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 &lt; 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 &lt; 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&nbsp;&lt; 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 &lt; 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.

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