scholarly journals Estrogen Modulation of Endothelial Nitric Oxide Synthase

2002 ◽  
Vol 23 (5) ◽  
pp. 665-686 ◽  
Author(s):  
Ken L. Chambliss ◽  
Philip W. Shaul
Keyword(s):  
Nitric Oxide ◽  
Basic Research ◽  
Heat Shock Protein 90 ◽  
No Production ◽  
Downstream Signaling ◽  
Estrogen Response ◽  
Enos Phosphorylation ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Nongenomic Effects

Abstract Over the past decade, clinical and basic research has demonstrated that estrogen has a dramatic impact on the response to vascular injury and the development of atherosclerosis. Further work has indicated that this is at least partially mediated by an enhancement in nitric oxide (NO) production by the endothelial isoform of NO synthase (eNOS) due to increases in both eNOS expression and level of activation. The effects on eNOS abundance are primarily mediated at the level of gene transcription, and they are dependent on estrogen receptors (ERs), which classically serve as transcription factors, but they are independent of estrogen response element action. Estrogen also has potent nongenomic effects on eNOS activity mediated by a subpopulation of ERα localized to caveolae in endothelial cells, where they are coupled to eNOS in a functional signaling module. These observations, which emphasize dependence on cell surface-associated receptors, provide evidence for the existence of a steroid receptor fast-action complex, or SRFC, in caveolae. Estrogen binding to ERα on the SRFC in caveolae leads to Gαi activation, which mediates downstream events. The downstream signaling includes activation of tyrosine kinase-MAPK and Akt/protein kinase B signaling, stimulation of heat shock protein 90 binding to eNOS, and perturbation of the local calcium environment, leading to eNOS phosphorylation and calmodulin-mediated eNOS stimulation. These unique genomic and nongenomic processes are critical to the vasoprotective and atheroprotective characteristics of estrogen. In addition, they serve as excellent paradigms for further elucidation of novel mechanisms of steroid hormone action.

Microparticles from Patients with the Acute Coronary Syndrome Impair Vasodilatation by Inhibiting the Akt/eNOS-Hsp90 Signaling Pathway

Cardiology ◽  
2015 ◽  
Vol 132 (4) ◽  
pp. 252-260 ◽  
Author(s):  
Wen-Qi Han ◽  
Feng-Jun Chang ◽  
Qun-Rang Wang ◽  
Jun-Qiang Pan
Keyword(s):  
Nitric Oxide ◽  
Acute Coronary Syndrome ◽  
Endothelial Dysfunction ◽  
Heat Shock Protein 90 ◽  
No Production ◽  
Healthy Controls ◽  
Coronary Syndrome ◽  
Enos Phosphorylation ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Objectives: Endothelial dysfunction is involved in the development of the acute coronary syndrome (ACS). Plasma microparticles (MPs) from other diseases have been demonstrated to initiate coagulation and endothelial dysfunction. However, whether MPs from ACS patients impair vasodilatation and endothelial function remains unclear. Methods: Patients (n = 62) with ACS and healthy controls (n = 30) were recruited for MP isolation. Rat thoracic aortas were incubated with MPs from ACS patients or healthy controls to determine the effects of MPs on endothelial-dependent vasodilatation, the phosphorylation of Akt and endothelial nitric oxide synthase (eNOS), the interaction of eNOS with heat shock protein 90 (Hsp90), and nitric oxide (NO) and superoxide anion (O2-) production. The origin of MPs was assessed by flow cytometry. Results: MP concentrations were increased in patients with ACS compared with healthy controls. They were positively correlated with the degree of coronary artery stenosis. MPs from ACS patients impair endothelial-dependent vasodilatation, decrease both Akt and eNOS phosphorylation, decrease the interaction between eNOS and Hsp90, and decrease NO production but increase O2- generation in rat thoracic aortas. Endothelial-derived MPs and platelet-derived MPs made up nearly 75% of MPs. Conclusions: Our data indicate that MPs from ACS patients negatively affect endothelial-dependent vasodilatation via Akt/eNOS-Hsp90 pathways.

scholarly journals Cadmium reduces nitric oxide production by impairing phosphorylation of endothelial nitric oxide synthase

2008 ◽  
Vol 86 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Syamantak Majumder ◽  
Ajit Muley ◽  
Gopi Krishna Kolluru ◽  
Samir Saurabh ◽  
K. P. Tamilarasan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Function ◽  
Egg Yolk ◽  
Cellular Migration ◽  
No Production ◽  
Enos Phosphorylation ◽  
Low Levels ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Cadmium (Cd) perturbs vascular health and interferes with endothelial function. However, the effects of exposing endothelial cells to low doses of Cd on the production of nitric oxide (NO) are largely unknown. The objective of the present study was to evaluate these effects by using low levels of CdCl2 concentrations, ranging from 10 to 1000 nmol/L. Cd perturbations in endothelial function were studied by employing wound-healing and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays. The results suggest that a CdCl2 concentration of 100 nmol/L maximally attenuated NO production, cellular migration, and energy metabolism in endothelial cells. An egg yolk angiogenesis model was employed to study the effect of Cd exposure on angiogenesis. The results demonstrate that NO supplementation restored Cd-attenuated angiogenesis. Immunofluorescence, Western blot, and immuno-detection studies showed that low levels of Cd inhibit NO production in endothelial cells by blocking eNOS phosphorylation, which is possibly linked to processes involving endothelial function and dysfunction, including angiogenesis.

scholarly journals Ablation of eNOS does not promote adipose tissue inflammation

2016 ◽  
Vol 310 (8) ◽  
pp. R744-R751 ◽  
Author(s):  
Thomas J. Jurrissen ◽  
Ryan D. Sheldon ◽  
Michelle L. Gastecki ◽  
Makenzie L. Woodford ◽  
Terese M. Zidon ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Adipose Tissue ◽  
Control Diet ◽  
Western Diet ◽  
No Production ◽  
Wild Type ◽  
Oxphos Complex ◽  
Enos Phosphorylation ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Adipose tissue (AT) inflammation is a hallmark characteristic of obesity and an important determinant of insulin resistance and cardiovascular disease; therefore, a better understanding of factors regulating AT inflammation is critical. It is well established that reduced vascular endothelial nitric oxide (NO) bioavailability promotes arterial inflammation; however, the role of NO in modulating inflammation in AT remains disputed. In the present study, 10-wk-old C57BL6 wild-type and endothelial nitric oxide synthase (eNOS) knockout male mice were randomized to either a control diet (10% kcal from fat) or a Western diet (44.9% kcal from fat, 17% sucrose, and 1% cholesterol) for 18 wk ( n = 7 or 8/group). In wild-type mice, Western diet-induced obesity led to increased visceral white AT expression of inflammatory genes (e.g., MCP1, TNF-α, and CCL5 mRNAs) and markers of macrophage infiltration (e.g., CD68, ITGAM, EMR1, CD11C mRNAs, and Mac-2 protein), as well as reduced markers of mitochondrial content (e.g., OXPHOS complex I and IV protein). Unexpectedly, these effects of Western diet on visceral white AT were not accompanied by decreases in eNOS phosphorylation at Ser-1177 or increases in eNOS phosphorylation at Thr-495. Also counter to expectations, eNOS knockout mice, independent of the diet, were leaner and did not exhibit greater white or brown AT inflammation compared with wild-type mice. Collectively, these findings do not support the hypothesis that reduced NO production from eNOS contributes to obesity-related AT inflammation.

scholarly journals The role of HYAL2 in LSS-induced glycocalyx impairment and the PKA-mediated decrease in eNOS–Ser-633 phosphorylation and nitric oxide production

2016 ◽  
Vol 27 (25) ◽  
pp. 3972-3979 ◽  
Author(s):  
Xiangquan Kong ◽  
Liang Chen ◽  
Peng Ye ◽  
Zhimei Wang ◽  
Junjie Zhang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Shear Stress ◽  
Umbilical Vein ◽  
Endothelial Glycocalyx ◽  
No Production ◽  
Enos Phosphorylation ◽  
Umbilical Vein Endothelial Cells ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Hyaluronan (HA) in the endothelial glycocalyx serves as a mechanotransducer for high-shear-stress–stimulated endothelial nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) production. Low shear stress (LSS) has been shown to contribute to endothelial inflammation and atherosclerosis by impairing the barrier and mechanotransduction properties of the glycocalyx. Here we focus on the possible role of hyaluronidase 2 (HYAL2) in LSS-induced glycocalyx impairment and the resulting alterations in eNOS phosphorylation and NO production in human umbilical vein endothelial cells (HUVECs). We show that LSS strongly activates HYAL2 to degrade HA in the glycocalyx. The dephosphorylation of eNOS–Ser-633 under LSS was triggered after HA degradation by hyaluronidase and prevented by repairing the glycocalyx with high–molecular weight hyaluronan. Knocking down HYAL2 in HUVECs protected against HA degradation in the glycocalyx by inhibiting the expression and activity of HYAL2 and further blocked the dephosphorylation of eNOS–Ser-633 and the decrease in NO production in response to LSS. The LSS-induced dephosphorylation of PKA was completely abrogated in HYAL2 siRNA–transfected HUVECs. The LSS-induced dephosphorylation of eNOS–Ser-633 was also reversed by the PKA activator 8-Br-cAMP. We thus suggest that LSS inhibits eNOS–Ser-633 phosphorylation and, at least partially, NO production by activating HYAL2 to degrade HA in the glycocalyx.

Increased cardiac microvascular permeability and activation of cardiac endothelial nitric oxide synthase in high tidal volume ventilation-induced lung injury

2010 ◽  
Vol 4 (1) ◽  
pp. 27-36
Author(s):  
Ming-Jui Hung ◽  
Ming-Yow Hung ◽  
Wen-Jin Cherng ◽  
Li-Fu Li
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Lung Injury ◽  
Tidal Volume ◽  
Endothelial Nitric Oxide Synthase ◽  
Microvascular Permeability ◽  
Akt Phosphorylation ◽  
Enos Phosphorylation ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Abstract Background: Positive pressure ventilation with large tidal volumes has been shown to cause lung injury via the serine/threonine kinase-protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS)-pathways. However, the effects of high tidal volume (VT) ventilation on the heart are unclear. Objectives: Evaluate the effect of VT ventilation on the cardiac vascular permeability and intracellular Akt and eNOS signaling pathway. Methods: C57BL/6 and Akt knock-out (heterozygotes, +/−) mice were exposed to high VT (30 mL/kg) mechanical ventilation with room air for one and/or five hours. Results: High VT ventilation increased cardiac microvascular permeability and eNOS phosphorylation in a timedependent manner. Serum cardiac troponin I was increased after one hour of high VT ventilation. Cardiac Akt phosphorylation was accentuated after one hour and attenuated after five hours of high VT ventilation. Pharmacological inhibition of Akt with LY294002 and high VT ventilation of Akt+/− mice attenuated cardiac Akt phosphorylation, but not eNOS phosphorylation. Conclusion: High VT ventilation increased cardiac myocardial injury, microvascular permeability, and eNOS phosphorylation. Involvement of cardiac Akt in high VT ventilation was transient.

scholarly journals Rho GTPase/Rho Kinase Negatively Regulates Endothelial Nitric Oxide Synthase Phosphorylation through the Inhibition of Protein Kinase B/Akt in Human Endothelial Cells

2002 ◽  
Vol 22 (24) ◽  
pp. 8467-8477 ◽  
Author(s):  
Xiu-Fen Ming ◽  
Hema Viswambharan ◽  
Christine Barandier ◽  
Jean Ruffieux ◽  
Kozo Kaibuchi ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Nitric Oxide Synthase ◽  
Rho Gtpase ◽  
Protein Kinase B ◽  
Rho Kinase ◽  
Enos Expression ◽  
Enos Phosphorylation ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

ABSTRACT Endothelial nitric oxide synthase (eNOS) is an important regulator of cardiovascular homeostasis by production of nitric oxide (NO) from vascular endothelial cells. It can be activated by protein kinase B (PKB)/Akt via phosphorylation at Ser-1177. We are interested in the role of Rho GTPase/Rho kinase (ROCK) pathway in regulation of eNOS expression and activation. Using adenovirus-mediated gene transfer in human umbilical vein endothelial cells (HUVECs), we show here that both active RhoA and ROCK not only downregulate eNOS gene expression as reported previously but also inhibit eNOS phosphorylation at Ser-1177 and cellular NO production with concomitant suppression of PKB activation. Moreover, coexpression of a constitutive active form of PKB restores the phosphorylation but not gene expression of eNOS in the presence of active RhoA. Furthermore, we show that thrombin inhibits eNOS phosphorylation, as well as expression via Rho/ROCK pathway. Expression of the active PKB reverses eNOS phosphorylation but has no effect on downregulation of eNOS expression induced by thrombin. Taken together, these data demonstrate that Rho/ROCK pathway negatively regulates eNOS phosphorylation through inhibition of PKB, whereas it downregulates eNOS expression independent of PKB.

scholarly journals Protein kinase Cδ regulates endothelial nitric oxide synthase expression via Akt activation and nitric oxide generation

2008 ◽  
Vol 294 (3) ◽  
pp. L582-L591 ◽  
Author(s):  
Neetu Sud ◽  
Stephen Wedgwood ◽  
Stephen M. Black
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Promoter Activity ◽  
Dominant Negative ◽  
No Production ◽  
Enos Expression ◽  
Akt Activation ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

In this study, we explore the roles of the delta isoform of PKC (PKCδ) in the regulation of endothelial nitric oxide synthase (eNOS) activity in pulmonary arterial endothelial cells isolated from fetal lambs (FPAECs). Pharmacological inhibition of PKCδ with either rottlerin or with the peptide, δV1-1, acutely attenuated NO production, and this was associated with a decrease in phosphorylation of eNOS at Ser1177 (S1177). The chronic effects of PKCδ inhibition using either rottlerin or the overexpression of a dominant negative PKCδ mutant included the downregulation of eNOS gene expression that was manifested by a decrease in both eNOS promoter activity and protein expression after 24 h of treatment. We also found that PKCδ inhibition blunted Akt activation as observed by a reduction in phosphorylated Akt at position Ser473. Thus, we conclude that PKCδ is actively involved in the activation of Akt. To determine the effect of Akt on eNOS signaling, we overexpressed a dominant negative mutant of Akt and determined its effect of NO generation, eNOS expression, and phosphorylation of eNOS at S1177. Our results demonstrated that Akt inhibition was associated with decreased NO production that correlated with reduced phosphorylation of eNOS at S1177, and decreased eNOS promoter activity. We next evaluated the effect of endogenously produced NO on eNOS expression by incubating FPAECs with the eNOS inhibitor 2-ethyl-2-thiopseudourea (ETU). ETU significantly inhibited NO production, eNOS promoter activity, and eNOS protein levels. Together, our data indicate involvement of PKCδ-mediated Akt activation and NO generation in maintaining eNOS expression.

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.

Endothelin stimulates endothelial nitric oxide synthase expression in the thick ascending limb

2004 ◽  
Vol 287 (2) ◽  
pp. F231-F235 ◽  
Author(s):  
Marcela Herrera ◽  
Jeffrey L. Garvin
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Receptor Antagonist ◽  
Endothelial Nitric Oxide Synthase ◽  
No Production ◽  
Thick Ascending Limb ◽  
Enos Expression ◽  
No Release ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Endothelin-1 (ET-1) acutely inhibits NaCl reabsorption by the thick ascending limb (THAL) by activating the ETB receptor, stimulating endothelial nitric oxide synthase (eNOS), and releasing nitric oxide (NO). In nonrenal tissue, chronic exposure to ET-1 stimulates eNOS expression via the ETB receptor and activation of phosphatidylinositol 3-kinase (PI3K). We hypothesized that ET-1 increases eNOS expression in the THAL by binding to ETB receptors and stimulating PI3K. In primary cultures of medullary THALs treated for 24 h, eNOS expression increased by 36 ± 18% with 0.01 nM ET-1, 123 ± 30% with 0.1 nM ( P < 0.05; n = 5), and 71 ± 30% with 1 nM, whereas 10 nM had no effect. BQ-788, a selective ETB receptor antagonist, completely blocked stimulation of eNOS expression caused by 0.1 nM ET-1 (12 ± 25 vs. 120 ± 40% for ET-1 alone; P < 0.05; n = 5). BQ-123, a selective ETA receptor antagonist, did not affect the increase in eNOS caused by 0.1 nM ET-1. Sarafotoxin c (S6c; 0.1 μM), a selective ETB receptor agonist, increased eNOS expression by 77 ± 30% ( P < 0.05; n = 6). Wortmannin (0.01 μM), a PI3K inhibitor, completely blocked the stimulatory effect of 0.1 μM S6c (77 ± 30 vs. −28 ± 9%; P < 0.05; n = 6). To test whether the increase in eNOS expression heightens activity, we measured NO release in response to simultaneous treatment with l-arginine, ionomycin, and clonidine using a NO-sensitive electrode. NO release by control cells was 337 ± 61 and 690 ± 126 pA in ET-1-treated cells ( P < 0.05; n = 5). Taken together, these data suggest that ET-1 stimulates THAL eNOS, activating ETB receptors and PI3K and thereby increasing NO production.

scholarly journals Nitric oxide function in atherosclerosis

1997 ◽  
Vol 6 (1) ◽  
pp. 3-21 ◽  
Author(s):  
K. E. Matthys ◽  
H. Bult
Keyword(s):  
Nitric Oxide ◽  
Leukocyte Adhesion ◽  
Atherosclerotic Lesion ◽  
Vascular Wall ◽  
Early Event ◽  
No Production ◽  
Oxygen Intermediates ◽  
Atherosclerotic Lesions ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Atherosclerosis is a chronic inflammatory process in the intima of conduit arteries, which disturbs the endothelium-dependent regulation of the vascular tone by the labile liposoluble radical nitric oxide (NO) formed by the constitutive endothelial nitric oxide synthase (eNOS). This defect predisposes to coronary vasospasm and cardiac ischaemia, with anginal pain as the typical clinical manifestation. It is now appreciated that endothelial dysfunction is an early event in atherogenesis and that it may also involve the microcirculation, in which atherosclerotic lesions do not develop. On the other hand, the inflammatory environment in atherosclerotic plaques may result in the expression of the inducible NO synthase (iNOS) isozyme. Whether the dysfunction in endothelial NO production is causal to, or the result of, atherosclerotic lesion formation is still highly debated. Most evidence supports the hypothesis that constitutive endothelial NO release protects against atherogenesis e.g. by preventing smooth muscle cell proliferation and leukocyte adhesion. Nitric oxide generated by the inducible isozyme may be beneficial by replacing the failing endothelial production but excessive release may damage the vascular wall cells, especially in combination with reactive oxygen intermediates.

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