scholarly journals Modulation of pulmonary endothelial endothelin B receptor expression and signaling: implications for experimental hepatopulmonary syndrome

2007 ◽  
Vol 292 (6) ◽  
pp. L1467-L1472 ◽  
Author(s):  
Liping Tang ◽  
Bao Luo ◽  
Rakesh P. Patel ◽  
Yiqun Ling ◽  
Junlan Zhang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Shear Stress ◽  
Portal Hypertension ◽  
Hepatopulmonary Syndrome ◽  
Receptor Expression ◽  
No Production ◽  
Laminar Shear Stress ◽  
Akt Activation ◽  
Microvascular Endothelial ◽  
Endothelin B

The hepatopulmonary syndrome (HPS) results from intrapulmonary vasodilation in the setting of cirrhosis and portal hypertension. In experimental HPS, pulmonary endothelial endothelin B (ETB) receptor overexpression and increased circulating endothelin-1 (ET-1) contribute to vasodilation through enhanced endothelial nitric oxide synthase (eNOS)-derived nitric oxide (NO) production. In both experimental cirrhosis and prehepatic portal hypertension, ETB receptor overexpression correlates with increased vascular shear stress, a known modulator of ETB receptor expression. We investigated the mechanisms of pulmonary endothelial ETB receptor-mediated eNOS activation by ET-1 in vitro and in vivo. The effect of shear stress on ETB receptor expression was assessed in rat pulmonary microvascular endothelial cells (RPMVECs). The consequences of ETB receptor overexpression on ET-1-dependent ETB receptor-mediated eNOS activation were evaluated in RPMVECs and in prehepatic portal hypertensive animals exposed to exogenous ET-1. Laminar shear stress increased ETB receptor expression in RPMVECs without altering mRNA stability. Both shear-mediated and targeted overexpression of the ETB receptor enhanced ET-1-mediated ETB receptor-dependent eNOS activation in RPMVECs through Ca2+-mediated signaling pathways and independent of Akt activation. In prehepatic portal hypertensive animals relative to control, ET-1 administration also activated eNOS independent of Akt activation and triggered HPS. These findings support that increased pulmonary microvascular endothelial ETB receptor expression modulates ET-1-mediated eNOS activation, independent of Akt, and contributes to the development of HPS.

scholarly journals The Effect of Race and Shear Stress on CRP-Induced Responses in Endothelial Cells

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Chenyi Ling ◽  
Marc D. Cook ◽  
Heather Grimm ◽  
Maitha Aldokhayyil ◽  
Dulce Gomez ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Function ◽  
Racial Differences ◽  
Umbilical Vein ◽  
Receptor Expression ◽  
No Production ◽  
Laminar Shear Stress ◽  
Enos Expression

Background. C-reactive protein (CRP) is an independent biomarker of systemic inflammation and a predictor of future cardiovascular disease (CVD). More than just a pure bystander, CRP directly interacts with endothelial cells to decrease endothelial nitric oxide synthase (eNOS) expression and bioactivity, decrease nitric oxide (NO) production, and increase the release of vasoconstrictors and adhesion molecules. Race is significantly associated with CRP levels and CVD risks. With aerobic exercise, the vessel wall is exposed to chronic high laminar shear stress (HiLSS) that shifts the endothelium phenotype towards an anti-inflammatory, antioxidant, antiapoptotic, and antiproliferative environment. Thus, the purpose of this study was to assess the racial differences concerning the CRP-induced effects in endothelial cells and the potential role of HiLSS in mitigating these differences. Methods. Human umbilical vein endothelial cells (HUVECs) from four African American (AA) and four Caucasian (CA) donors were cultured and incubated under the following conditions: (1) static control, (2) CRP (10 μg/mL, 24 hours), (3) CRP receptor (FcγRIIB) inhibitor followed by CRP stimulation, (4) HiLSS (20 dyne/cm2, 24 hours), and (5) HiLSS followed by CRP stimulation. Results. AA HUVECs had significantly higher FcγRIIB receptor expression under both basal and CRP incubation conditions. Blocking FcγRIIB receptor significantly attenuated the CRP-induced decrements in eNOS expression only in AA HUVECs. Finally, HiLSS significantly counteracted CRP-induced effects. Conclusion. Understanding potential racial differences in endothelial function is important to improve CVD prevention. Our results shed light on FcγRIIB receptor as a potential contributor to racial differences in endothelial function in AA.

scholarly journals Pentoxifylline attenuation of experimental hepatopulmonary syndrome

2007 ◽  
Vol 102 (3) ◽  
pp. 949-955 ◽  
Author(s):  
Junlan Zhang ◽  
Yiqun Ling ◽  
Liping Tang ◽  
Bao Luo ◽  
Balu K. Chacko ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Hepatopulmonary Syndrome ◽  
Microvascular Endothelial Cells ◽  
Enos Expression ◽  
Akt Activation ◽  
Pulmonary Microvascular Endothelial Cells ◽  
Tnf Α

Hepatopulmonary syndrome (HPS) following rat common bile duct ligation results from pulmonary molecular changes that may be influenced by circulating TNF-α and increased vascular shear stress, through activation of NF-κB or Akt. Increased pulmonary microvascular endothelin B (ETB) receptor and endothelial nitric oxide synthase (eNOS) levels contribute to nitric oxide production and the development of experimental HPS. Pentoxifylline (PTX), a phosphodiesterase and nonspecific TNF-α inhibitor, ameliorates experimental HPS when begun before hepatic injury. However, how PTX influences the molecular events associated with initiation of experimental HPS after liver injury is established is unknown. We assessed the effects of PTX on the molecular and physiological features of HPS in vivo and on shear stress or TNF-α-mediated events in rat pulmonary microvascular endothelial cells in vitro. PTX significantly improved HPS without altering portal or systemic hemodynamics and downregulated pulmonary ETB receptor levels and eNOS expression and activation. These changes were associated with a reduction in circulating TNF levels and NF-κB activation and complete inhibition of Akt activation. In rat pulmonary microvascular endothelial cells, PTX inhibited shear stress-induced ETB receptor and eNOS expression and eNOS activation. These effects were also associated with inhibition of Akt activation and were reproduced by wortmanin. In contrast, TNF-α had no effects on endothelial ETB and eNOS alterations in vitro. PTX has direct effects in the pulmonary microvasculature, likely mediated through Akt inhibition, that ameliorate experimental HPS.

scholarly journals Attenuation of experimental hepatopulmonary syndrome in endothelin B receptor-deficient rats

2009 ◽  
Vol 296 (4) ◽  
pp. G704-G708 ◽  
Author(s):  
Junlan Zhang ◽  
Yiqun Ling ◽  
Liping Tang ◽  
Bao Luo ◽  
David M. Pollock ◽  
...  
Keyword(s):  
Hepatopulmonary Syndrome ◽  
Receptor Activation ◽  
Receptor Expression ◽  
Similar Degree ◽  
No Production ◽  
Wild Type ◽  
Common Bile Duct Ligation ◽  
Pulmonary Endothelium ◽  
Duct Ligation ◽  
Endothelin B

Experimental hepatopulmonary syndrome (HPS) after common bile duct ligation (CBDL) in rat is accompanied by increased lung vascular endothelial endothelin B (ETB) receptor expression and increased circulating levels of endothelin-1 (ET-1). The onset of HPS is hypothesized to be triggered by ET-1/ETB receptor activation of endothelial nitric oxide synthase (eNOS)-derived NO production in the pulmonary endothelium. However, whether functional pulmonary vascular ETB receptors are required for the development of experimental HPS is not defined. We evaluated the effects of vascular ETB receptor deficiency on the development of experimental HPS. The molecular and physiological alterations of HPS were compared in 2-wk CBDL wild-type and ETB receptor-deficient (transgenic sl/sl) rats. Relative to wild-type rats, basal hepatic and plasma ET-1 levels were elevated in sl/sl controls although, unlike wild-type animals circulating ET-1 levels, did not increase further after CBDL in sl/sl animals. In contrast to wild-type animals, ETB receptor-deficient rats did not develop increased Akt and eNOS expression and activation and did not develop gas exchange abnormalities of HPS after CBDL. There was a similar degree of pulmonary intravascular monocyte accumulation in both 2-wk CBDL sl/sl and wild-type animals. In conclusion, ETB receptor deficiency inhibits lung Akt/eNOS activation and prevents the onset of experimental HPS after CBDL. This effect is independent of inhibition of pulmonary intravascular monocyte accumulation. These results demonstrate that ET-1/ETB receptor signaling plays a key role in the initiation of experimental HPS.

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.

Laminar Flow on Endothelial Cells Suppresses eNOS O-GlcNAcylation to Promote eNOS Activity

2021 ◽  
Author(s):  
Sarah Basehore ◽  
Samantha Bohlman ◽  
Callie Weber ◽  
Swathi Swaminathan ◽  
Yuji Zhang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Laminar Flow ◽  
No Production ◽  
Disturbed Flow ◽  
Enos Activity ◽  
Enos Phosphorylation ◽  
Steady Laminar ◽  
In Cells

Rationale: In diabetic animals as well as high glucose cell culture conditions, endothelial nitric oxide synthase (eNOS) is heavily O-GlcNAcylated, which inhibits its phosphorylation and nitric oxide (NO) production. It is unknown, however, whether varied blood flow conditions, which affect eNOS phosphorylation, modulate eNOS activity via O-GlcNAcylation-dependent mechanisms. Objective: The goal of this study was to test if steady laminar flow, but not oscillating disturbed flow, decreases eNOS O-GlcNAcylation, thereby elevating eNOS phosphorylation and NO production. Methods and Results: Human umbilical vein endothelial cells (HUVEC) were exposed to either laminar flow (20 dynes/cm2 shear stress) or oscillating disturbed flow (4{plus minus}6 dynes/cm2 shear stress) for 24 hours in a cone-and-plate device. eNOS O-GlcNAcylation was almost completely abolished in cells exposed to steady laminar but not oscillating disturbed flow. Interestingly, there was no change in protein level or activity of key O-GlcNAcylation enzymes (OGT, OGA, or GFAT). Instead, metabolomics data suggest that steady laminar flow decreases glycolysis and hexosamine biosynthetic pathway (HBP) activity, thereby reducing UDP-GlcNAc pool size and consequent O-GlcNAcylation. Inhibition of glycolysis via 2-deoxy-2-glucose (2-DG) in cells exposed to disturbed flow efficiently decreased eNOS O-GlcNAcylation, thereby increasing eNOS phosphorylation and NO production. Finally, we detected significantly higher O-GlcNAcylated proteins in endothelium of the inner aortic arch in mice, suggesting that disturbed flow increases protein O-GlcNAcylation in vivo. Conclusions: Our data demonstrate that steady laminar but not oscillating disturbed flow decreases eNOS O-GlcNAcylation by limiting glycolysis and UDP-GlcNAc substrate availability, thus enhancing eNOS phosphorylation and NO production. This research shows for the first time that O-GlcNAcylation is regulated by mechanical stimuli, relates flow-induced glycolytic reductions to macrovascular disease, and highlights targeting HBP metabolic enzymes in endothelial cells as a novel therapeutic strategy to restore eNOS activity and prevent EC dysfunction in cardiovascular disease.

Nitric oxide limits coronary vasoconstriction by a shear stress-dependent mechanism

2001 ◽  
Vol 281 (2) ◽  
pp. H796-H803 ◽  
Author(s):  
David W. Stepp ◽  
Daphne Merkus ◽  
Yasuhiro Nishikawa ◽  
William M. Chilian
Keyword(s):  
Nitric Oxide ◽  
Shear Stress ◽  
Coronary Microcirculation ◽  
Shear Stresses ◽  
No Production ◽  
Small Arteries ◽  
Inner Diameter ◽  
Stress Dependent ◽  
Dependent Mechanism

Increases in shear stress promote coronary vasodilation by stimulating the production of nitric oxide (NO). Whether shear stress-induced NO production also limits vasoconstriction in the coronary microcirculation in vivo is unknown. Accordingly, we measured microvascular diameter and flow velocity in the beating heart along with estimated blood viscosity to calculate shear stress during vasoconstriction with endothelin or vasopressin. Measurements were repeated in the presence of N G-monomethyl-l-arginine (l-NMMA) to inhibit NO production and BQ-788 to block NO-linked endothelin type B receptors. BQ-788 did not augment steady-state constriction to endothelin, suggesting that NO production via activation of this receptor is inconsequential. l-NMMA potentiated constriction to both agonists, particularly in small arteries (inner diameter >120 μm). Shear stresses in small arteries were elevated during constriction and further elevated during constriction after l-NMMA. These observations suggest that NO production limits vasoconstriction in the coronary microcirculation and that the principal stimulus for this governance is elevated shear stress. The degree of shear stress moderation of constriction is heterogeneously distributed, with small arteries displaying a higher degree of shear stress regulation than arterioles. These results provide the strongest evidence to date that shear stress-mediated production of NO exerts a “braking” influence on constriction in the coronary microcirculation.

ET-1 and TNF-α in HPS: analysis in prehepatic portal hypertension and biliary and nonbiliary cirrhosis in rats

2004 ◽  
Vol 286 (2) ◽  
pp. G294-G303 ◽  
Author(s):  
Bao Luo ◽  
Lichuan Liu ◽  
Liping Tang ◽  
Junlan Zhang ◽  
Yiqun Ling ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Portal Hypertension ◽  
Nitric Oxide Synthase ◽  
Receptor Expression ◽  
Heme Oxygenase 1 ◽  
Portal Vein Ligation ◽  
Biliary Cirrhosis ◽  
Duct Ligation ◽  
Tnf Α ◽  
Oxide Synthase

Common bile duct ligation (CBDL) triggers a molecular cascade resulting in the hepatopulmonary syndrome (HPS). Both increased hepatic endothelin-1 (ET-1) production and pulmonary vascular ETB receptor expression with stimulation of endothelial nitric oxide synthase and TNF-α mediated inducible nitric oxide synthase and heme oxygenase-1 expression in pulmonary intravascular macrophages occur. Whether biliary cirrhosis is unique in triggering ET-1 and TNF-α alterations and HPS is unknown. We evaluated for HPS in rat prehepatic portal hypertension [partial portal vein ligation (PVL)], biliary (CBDL) and nonbiliary [thioacetamide treatment (TAA)] cirrhosis, and assessed ET-1 infusion in normal and PVL animals. Control, PVL, CBDL, TAA-treated, and ET-1-infused PVL animals had ET-1 and TNF-α levels measured and underwent molecular and physiological evaluation for HPS. HPS developed only in biliary cirrhosis in association with increased plasma ET-1 and TNF-α levels and the development of established molecular changes in the pulmonary microvasculature. In contrast, PVL did not increase ET-1 or TNF-α levels and TAA treatment increased TNF-α levels alone, and neither resulted in the full development of molecular or physiological changes of HPS despite portal pressure increases similar to those after CBDL. Exogenous ET-1 increased TNF-α levels and triggered HPS after PVL. Combination of ET-1 and TNF-α overproduction is unique to biliary cirrhosis and associated with experimental HPS. ET-1 infusion increases TNF-α levels and triggers HPS in prehepatic portal hypertension. ET-1 and TNF-α interact to trigger pulmonary microvascular changes in experimental HPS.

Angiotensin II receptor subtypes determine induced NO production in rat glomerular mesangial cells

2000 ◽  
Vol 279 (6) ◽  
pp. F1092-F1100 ◽  
Author(s):  
Jörg Schwöbel ◽  
Tina Fischer ◽  
Bettina Lanz ◽  
Markus Mohaupt
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Mesangial Cells ◽  
Receptor Expression ◽  
Receptor Subtypes ◽  
No Production ◽  
Ang Ii ◽  
Glomerular Mesangial Cells ◽  
Nitrite Production ◽  
The Impact

Angiotensin II (ANG II) and nitric oxide (NO) have contrasting vascular effects, yet both sustain inflammatory responses. We investigated the impact of ANG II on lipopolysaccharide (LPS)/interferon-γ (IFN)-induced NO production in cultured rat mesangial cells (MCs). LPS/IFN-induced nitrite production, the inducible form of nitric oxide synthase (NOS-2) mRNA, and protein expression were dose dependently inhibited by ANG II on coincubation, which was abolished on ANG II type 2 (AT2) receptor blockade by PD-123319. Homology-based RT-PCR verified the presence of AT1A, AT1B, and AT2 receptors. To shift the AT receptor expression toward the type 1 receptor, two sets of experiments were performed: LPS/IFN preincubation for 24 h was followed by 8-h coincubation with ANG II; or during 24-h coincubation of LPS/IFN and ANG II, dexamethasone was added for the last 6-h period. Both led to an amplified overall expression of NOS-2 protein and NO production that was inhibitable by actinomycin D in the first setup. Induced NO production was enhanced via the AT1 receptor; however, it was diminished via the AT2 receptor. In conclusion, induced NO production is negatively controlled by the AT2, whereas AT1 receptor stimulation enhanced NO synthesis in MCs. The overall NO availability depended on the onset of the inflammatory stimuli with respect to ANG II exposure and the available AT receptors.

scholarly journals Laminar Shear Stress Regulates Endothelial Kinin B1 Receptor Expression and Function

2009 ◽  
Vol 29 (11) ◽  
pp. 1757-1763 ◽  
Author(s):  
Johan Duchene ◽  
Cécile Cayla ◽  
Sandrine Vessillier ◽  
Ramona Scotland ◽  
Kazuo Yamashiro ◽  
...  
Keyword(s):  
Shear Stress ◽  
Receptor Expression ◽  
Laminar Shear Stress ◽  
B1 Receptor ◽  
Kinin B1 Receptor ◽  
And Function ◽  
Laminar Shear

scholarly journals High salt induces autocrine actions of ET-1 on inner medullary collecting duct NO production via upregulated ETB receptor expression

2016 ◽  
Vol 311 (2) ◽  
pp. R263-R271 ◽  
Author(s):  
Kelly Anne Hyndman ◽  
Courtney Dugas ◽  
Alexandra M. Arguello ◽  
Traci T. Goodchild ◽  
Kathleen M. Buckley ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Collecting Duct ◽  
High Salt ◽  
Receptor Expression ◽  
Electrolyte Balance ◽  
No Production ◽  
Inner Medullary Collecting Duct ◽  
Nitrite Production ◽  
Vasa Recta ◽  
Medullary Collecting Duct

The collecting duct endothelin-1 (ET-1), endothelin B (ETB) receptor, and nitric oxide synthase-1 (NOS1) pathways are critical for regulation of fluid-electrolyte balance and blood pressure control during high-salt feeding. ET-1, ETB receptor, and NOS1 are highly expressed in the inner medullary collecting duct (IMCD) and vasa recta, suggesting that there may be cross talk or paracrine signaling between the vasa recta and IMCD. The purpose of this study was to test the hypothesis that endothelial cell-derived ET-1 (paracrine) and collecting duct-derived ET-1 (autocrine) promote IMCD nitric oxide (NO) production through activation of the ETB receptor during high-salt feeding. We determined that after 7 days of a high-salt diet (HS7), there was a shift to 100% ETB expression in IMCDs, as well as a twofold increase in nitrite production (a metabolite of NO), and this increase could be prevented by acute inhibition of the ETB receptor. ETB receptor blockade or NOS1 inhibition also prevented the ET-1-dependent decrease in ion transport from primary IMCDs, as determined by transepithelial resistance. IMCD were also isolated from vascular endothelial ET-1 knockout mice (VEETKO), collecting duct ET-1 KO (CDET-1KO), and flox controls. Nitrite production by IMCD from VEETKO and flox mice was similarly increased twofold with HS7. However, IMCD NO production from CDET-1KO mice was significantly blunted with HS7 compared with flox control. Taken together, these data indicate that during high-salt feeding, the autocrine actions of ET-1 via upregulation of the ETB receptor are critical for IMCD NO production, facilitating inhibition of ion reabsorption.

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