scholarly journals Role of local production of endothelium-derived nitric oxide on cGMP signaling and S-nitrosylation

2010 ◽  
Vol 298 (1) ◽  
pp. H112-H118 ◽  
Author(s):  
Jin Qian ◽  
Qian Zhang ◽  
Jarrod E. Church ◽  
David W. Stepp ◽  
Radu D. Rudic ◽  
...  

Nitric oxide (NO), synthesized by endothelial nitric oxide synthase (eNOS), exerts control over vascular function via two distinct mechanisms, the activation of soluble guanylate cyclase (sGC)/cGMP-dependent signaling or through S-nitrosylation of proteins with reactive thiols ( S-nitrosylation). Previous studies in cultured endothelial cells revealed that eNOS targeted to the plasma membrane (PM) releases greater amounts of NO compared with Golgi tethered eNOS. However, the significance of eNOS localization to sGC-dependent or -independent signaling is not known. Here we show that PM-targeted eNOS, when expressed in human aortic endothelial cells (HAEC) and isolated blood vessels, increases sGC/cGMP signaling to a greater extent than Golgi-localized eNOS. The ability of local NO production to influence sGC-independent mechanisms was also tested by monitoring the secretion of Von Willebrand factor (vWF), which is tonically inhibited by the S-nitrosylation of N-ethylmaleimide sensitive factor (NSF). In eNOS “knockdown” HAECs, vWF secretion was attenuated to a greater degree by PM eNOS compared with a Golgi-restricted eNOS. Moreover, the PM-targeted eNOS induced greater S-nitrosylation of NSF vs. Golgi eNOS. To distinguish between the amount of NO generated and the intracellular location of synthesis, we expressed Golgi and PM-targeted calcium-insensitive forms of eNOS in HAEC. These constructs, which generate equal amounts of NO regardless of location, produced equivalent increases in cGMP in bioassays and equal inhibition of vWF secretion. We conclude that the greater functional effects of PM eNOS are due to the increased amount of NO produced rather than effects derived from the local synthesis of NO.

Endocrinology ◽  
2012 ◽  
Vol 153 (7) ◽  
pp. 3190-3198 ◽  
Author(s):  
Hongwei Si ◽  
Jie Yu ◽  
Hongling Jiang ◽  
Hazel Lum ◽  
Dongmin Liu

We previously reported that genistein, a phytoestrogen, up-regulates endothelial nitric oxide synthase (eNOS) and prevents hypertension in rats that are independent of estrogen signaling machinery. However, how genistein regulates eNOS expression is unknown. In the present study, we show that genistein enhanced eNOS expression and NO synthesis in primary human aortic endothelial cells. Inhibition of extracellular signal regulated kinase, phosphoinositol-3 kinase, or protein kinase C did not affect genistein-enhanced eNOS expression and NO synthesis. However, chemical inhibition of protein kinase A (PKA) or adenoviral transfer of the specific endogenous PKA inhibitor gene completely abolished PKA activity and genistein-stimulated eNOS expression and NO production. Accordingly, genistein induced PKA activity and subsequent phosphorylation of cAMP response element (CRE)-binding protein (CREB) at Ser133. Suppression of CREB by small interfering RNA transfection abolished genistein-enhanced eNOS expression and NO production. Consistently, deletion of the CRE site within human eNOS promoter eliminated genistein-stimulated eNOS promoter activity. These findings provide the first evidence to our knowledge that genistein may play a beneficial role in vascular function through targeting the PKA/CREB/eNOS/NO signaling pathway.


2007 ◽  
Vol 293 (2) ◽  
pp. H1115-H1121 ◽  
Author(s):  
Bonnie L. Goodwin ◽  
Laura C. Pendleton ◽  
Monique M. Levy ◽  
Larry P. Solomonson ◽  
Duane C. Eichler

Endothelial dysfunction associated with elevated serum levels of TNF-α observed in diabetes, obesity, and congenital heart disease results, in part, from the impaired production of endothelial nitric oxide (NO). Cellular NO production depends absolutely on the availability of arginine, substrate of endothelial nitric oxide synthase (eNOS). In this report, evidence is provided demonstrating that treatment with TNF-α (10 ng/ml) suppresses not only eNOS expression but also the availability of arginine via the coordinate suppression of argininosuccinate synthase (AS) expression in aortic endothelial cells. Western blot and real-time RT-PCR demonstrated a significant and dose-dependent reduction of AS protein and mRNA when treated with TNF-α with a corresponding decrease in NO production. Reporter gene analysis demonstrated that TNF-α suppresses the AS proximal promoter, and EMSA analysis showed reduced binding to three essential Sp1 elements. Inhibitor studies suggested that the repression of AS expression by TNF-α may be mediated, in part, via the NF-κB signaling pathway. These findings demonstrate that TNF-α coordinately downregulates eNOS and AS expression, resulting in a severely impaired citrulline-NO cycle. The downregulation of AS by TNF-α is an added insult to endothelial function because of its important role in NO production and in endothelial viability.


Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3575
Author(s):  
Sujeong Jang ◽  
Seongsoo Lee ◽  
Heonyong Park

Cyclodextrins (CDs) are used as drug delivery agents. In this study, we examined whether CDs have an inflammatory effect on endothelial cells. First, we found that β-CD promoted cell proliferation in bovine aortic endothelial cells and elevated nitric oxide (NO) production through dephosphorylation of threonine-495 (T-495) in endothelial nitric oxide synthetase (eNOS). Dephosphorylation of T-495 is known to activate eNOS. Phosphorylation of T-495 was found to be catalyzed by protein kinase Cε (PKCε). We then found that β-CD inhibits binding of PKCε to diacylglycerol (DAG) via formation of a β-CD-DAG complex, indicating that β-CD inactivates PKCε. Furthermore, β-CD controls activation of PKCε by reducing the recruitment of PKCε into the plasma membrane. Finally, β-CD inhibits expression of intercellular and vascular cell adhesion molecule-1 by increasing NO via control of PKCε/eNOS and suppression of THP-1 cell adhesion to endothelial cells. These findings imply that β-CD plays an important role in anti-inflammatory processes.


2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Seonhee Kim ◽  
Ikjun Lee ◽  
Hee-Jung Song ◽  
Su-jeong Choi ◽  
Harsha Nagar ◽  
...  

Far-infrared ray (FIR) therapy has been reported to exert beneficial effects on cardiovascular function by elevating endothelial nitric oxide synthesis (eNOS) activity and nitric oxide (NO) production. Tetrahydrobiopterin (BH4) is a key determinant of eNOS-dependent NO synthesis in vascular endothelial cells. However, whether BH4 synthesis is associated with the effects of FIR on eNOS/NO production has not yet been investigated. In this study, we investigated the effects of FIR on BH4-dependent eNOS/NO production and vascular function. We used FIR-emitting sericite boards as an experimental material and placed human umbilical vein endothelial cells (HUVECs) and Sprague–Dawley rats on the boards with or without FIR irradiation and then evaluated vascular relaxation by detecting NO generation, BH4 synthesis, and Akt/eNOS activation. Our results showed that FIR radiation significantly enhanced Akt/eNOS phosphorylation and NO production in human endothelial cells and aorta tissues. FIR can also induce BH4 storage by elevating levels of enzymes (e.g., guanosine triphosphate cyclohydrolase-1, 6-pyruvoyl tetrahydrobiopterin synthase, sepiapterin reductase, and dihydrofolate reductase), which ultimately results in NO production. These results indicate that FIR upregulated eNOS-dependent NO generation via BH4 synthesis and Akt phosphorylation, which contributes to the regulation of vascular function. This might develop potential clinical application of FIR to treat vascular diseases by augmenting the BH4/NO pathway.


2000 ◽  
Vol 279 (4) ◽  
pp. F671-F678 ◽  
Author(s):  
Xiaohui Zhang ◽  
Hong Li ◽  
Haoli Jin ◽  
Zachary Ebin ◽  
Sergey Brodsky ◽  
...  

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.


2021 ◽  
Vol 22 (19) ◽  
pp. 10287
Author(s):  
Chih-Hsien Wu ◽  
Yi-Lin Chiu ◽  
Chung-Yueh Hsieh ◽  
Guo-Shiang Tsung ◽  
Lian-Shan Wu ◽  
...  

Cilostazol was suggested to be beneficial to retard in-stent atherosclerosis and prevent stent thrombosis. However, the mechanisms responsible for the beneficial effects of cilostazol are not fully understood. In this study, we attempted to verify the mechanism of the antithrombotic effect of cilostazol. Human umbilical vein endothelial cells (HUVECs) were cultured with various concentrations of cilostazol to verify its impact on endothelial cells. KLF2, silent information regulator transcript-1 (SIRT1), endothelial nitric oxide synthase (eNOS), and endothelial thrombomodulin (TM) expression levels were examined. We found cilostazol significantly activated KLF2 expression and KLF2-related endothelial function, including eNOS activation, Nitric oxide (NO) production, and TM secretion. The activation was regulated by SIRT1, which was also stimulated by cilostazol. These findings suggest that cilostazol may be capable of an antithrombotic and vasculoprotective effect in endothelial cells.


2004 ◽  
Vol 286 (3) ◽  
pp. H1043-H1056 ◽  
Author(s):  
Nikolaos M. Tsoukias ◽  
Mahendra Kavdia ◽  
Aleksander S. Popel

Nitric oxide (NO) plays many important physiological roles, including the regulation of vascular smooth muscle tone. In response to hemodynamic or agonist stimuli, endothelial cells produce NO, which can diffuse to smooth muscle where it activates soluble guanylate cyclase (sGC), leading to cGMP formation and smooth muscle relaxation. The close proximity of red blood cells suggests, however, that a significant amount of NO released will be scavenged by blood, and thus the issue of bioavailability of endothelium-derived NO to smooth muscle has been investigated experimentally and theoretically. We formulated a mathematical model for NO transport in an arteriole to test the hypothesis that transient, burst-like NO production can facilitate efficient NO delivery to smooth muscle and reduce NO scavenging by blood. The model simulations predict that 1) the endothelium can maintain a physiologically significant amount of NO in smooth muscle despite the presence of NO scavengers such as hemoglobin and myoglobin; 2) under certain conditions, transient NO release presents a more efficient way for activating sGC and it can increase cGMP formation severalfold; and 3) frequency-rather than amplitude-dependent control of cGMP formation is possible. This suggests that it is the frequency of NO bursts and perhaps the frequency of Ca2+ oscillations in endothelial cells that may limit cGMP formation and regulate vascular tone. The proposed hypothesis suggests a new functional role for Ca2+ oscillations in endothelial cells. Further experimentation is needed to test whether and under what conditions in silico predictions occur in vivo.


2011 ◽  
Vol 300 (4) ◽  
pp. C880-C887 ◽  
Author(s):  
Israel Ramirez-Sanchez ◽  
Lisandro Maya ◽  
Guillermo Ceballos ◽  
Francisco Villarreal

The consumption of cacao-derived (i.e., cocoa) products provides beneficial cardiovascular effects in healthy subjects as well as individuals with endothelial dysfunction such as smokers, diabetics, and postmenopausal women. The vascular actions of cocoa are related to enhanced nitric oxide (NO) production. These actions can be reproduced by the administration of the cacao flavanol (−)-epicatechin (EPI). To further understand the mechanisms behind the vascular action of EPI, we investigated the effects of Ca2+ depletion on endothelial nitric oxide (NO) synthase (eNOS) activation/phosphorylation and translocation. Human coronary artery endothelial cells were treated with EPI or with bradykinin (BK), a well-known Ca2+-dependent eNOS activator. Results demonstrate that both EPI and BK induce increases in intracellular calcium and NO levels. However, under Ca2+-free conditions, EPI (but not BK) is still capable of inducing NO production through eNOS phosphorylation at serine 615, 633, and 1177. Interestingly, EPI-induced translocation of eNOS from the plasmalemma was abolished upon Ca2+ depletion. Thus, under Ca2+-free conditions, EPI can stimulate NO synthesis independent of calmodulin binding to eNOS and of its translocation into the cytoplasm. We also examined the effect of EPI on the NO/cGMP/vasodilator-stimulated phosphoprotein (VASP) pathway activation in isolated Ca2+-deprived canine mesenteric arteries. Results demonstrate that under these conditions, EPI induces the activation of this vasorelaxation-related pathway and that this effect is inhibited by pretreatment with nitro-l-arginine methyl ester, suggesting a functional relevance for this phenomenon.


1995 ◽  
Vol 269 (3) ◽  
pp. C757-C765 ◽  
Author(s):  
B. J. Buckley ◽  
Z. Mirza ◽  
A. R. Whorton

Vascular endothelium responds to Ca(2+)-mobilizing agonists by producing nitric oxide (NO), a potent vasodilator and inhibitor of platelet aggregation. Regulation of constitutively expressed endothelial NO synthase (eNOS) in intact cells is not well understood. We investigated the kinetics of NO formation in response to Ca(2+)-mobilizing agonists, the requirement for extracellular L-arginine, and the role of NO in regulating eNOS activity. When endothelial cells were stimulated with bradykinin and ATP in the presence of 100 microM L-arginine, we observed a rapid and transient rise in intracellular Ca2+ concentration ([Ca2+]i) from 50 +/- 8 nM to 698 +/- 74 and 637 +/- 53 nM, respectively, and a rapid and transient rise in NO production from a basal level of 37 pmol.min-1.mg protein-1 to 256 and 275 pmol.min-1.mg protein-1, respectively. When cells were stimulated with A-23187 or thapsigargin in the presence of 100 microM L-arginine, we observed a sustained increase in [Ca2+]i and a sustained increase in NO production. The rate of NO synthesis was linear over 30 min, rising above control levels of 7 pmol/min to 53 pmol/min for A-23187 and 62 pmol/min for thapsigargin. Thapsigargin stimulated NO production and [Ca2+]i with 50% effective concentration values of 0.01 and 0.05 microM, respectively. Ca(2+)-stimulated NO production was attenuated by the NO synthase inhibitor NG-monomethyl-L-arginine, the removal of extracellular L-arginine, and the Ca(2+)-chelator ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid. When we exposed cells to NO gas (3.1 mM for 15 min) and S-nitrosoglutathione (10 mM for 1 h) thapsigargin-stimulated NO production was decreased by 50%.(ABSTRACT TRUNCATED AT 250 WORDS)


2003 ◽  
Vol 374 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Kennedy MAKONDO ◽  
Kazuhiro KIMURA ◽  
Naoki KITAMURA ◽  
Takanori KITAMURA ◽  
Daisuke YAMAJI ◽  
...  

Hepatocyte growth factor (HGF) causes endothelium-dependent vasodilation, but its relation to endothelial nitric oxide synthase (eNOS) activity remains to be elucidated. Treatment of bovine aortic endothelial cells with HGF increased eNOS activity within minutes, accompanied by an increase of activity-related site-specific phosphorylation of eNOS. The phosphorylation was completely abolished by pretreatment of the cells with a phosphoinositide 3-kinase (PI3K) inhibitor (wortmannin) and by transfection of dominant-negative Akt, and the enzyme activity was inhibited by wortmannin. In addition, eNOS activity and phosphorylation were abolished by pretreatment of the cells with an intracellular Ca2+-chelator, bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetra-acetic acid tetrakis(acetoxymethyl ester) (BAPTA/AM), with a suppression of Akt phosphorylation. These results suggest that HGF stimulates eNOS activity by a PI3K/Akt-dependent phosphorylation in a Ca2+-sensitive manner in vascular endothelial cells.


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