scholarly journals Increased superoxide leads to decreased flow-induced dilation in resistance arteries of Mn-SOD-deficient mice

2005 ◽  
Vol 288 (5) ◽  
pp. H2225-H2231 ◽  
Author(s):  
Changdong Yan ◽  
An Huang ◽  
Zhiping Wu ◽  
Pawel M. Kaminski ◽  
Michael S. Wolin ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Vascular Function ◽  
Manganese Superoxide Dismutase ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Enos Activity ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Enos Protein

The role of mitochondrial manganese-superoxide dismutase (Mn-SOD) in the maintenance of vascular function has not yet been studied. Thus we examined flow- and agonist-induced dilations in isolated mesenteric arteries (∼90 μm in diameter) of Mn-SOD heterozygous (Mn-SOD+/−) and wild-type (WT) mice. Increases in flow elicited dilations in all vessels, but the magnitude of the dilation was significantly less in vessels of Mn-SOD+/− mice than in those of WT mice (64 vs. 74% of passive diameter). Nω-nitro-l-arginine methyl ester inhibited the dilation in vessels of WT mice but had no effect on vessels of Mn-SOD+/− mice. Tempol or tiron (superoxide scavengers) increased flow-induced dilation in vessels of Mn-SOD+/− mice. Acetylcholine- and sodium nitroprusside-induced, but not adenosine-induced, dilations were also decreased in arteries of Mn-SOD+/− mice. Superoxide levels in the arteries of Mn-SOD+/− mice were significantly increased. Western blot analysis confirmed a 50% reduction of Mn-SOD protein in the vessels of Mn-SOD+/− mice. A 41% reduction in endothelial nitric oxide synthase (eNOS) protein and a 37% reduction in eNOS activity were also found in the vessels of Mn-SOD+/− mice. Whereas there was no difference in eNOS protein in kidney homogenates of WT and Mn-SOD+/− mice, a significant reduction of nitric oxide synthase activity was found in Mn-SOD+/− mice, which could be restored by the administration of tiron. We conclude that an increased concentration of superoxide due to reduced activity of Mn-SOD, which inactivates nitric oxide and inhibits eNOS activity, contributes to the impaired vasodilator function of isolated mesenteric arteries of Mn-SOD+/− mice. These results suggest that Mn-SOD contributes significantly to the regulation of vascular function.

scholarly journals Epithelial Na+ channel differentially contributes to shear stress-mediated vascular responsiveness in carotid and mesenteric arteries from mice

2018 ◽  
Vol 314 (5) ◽  
pp. H1022-H1032 ◽  
Author(s):  
Zoe Ashley ◽  
Sama Mugloo ◽  
Fiona J. McDonald ◽  
Martin Fronius
Keyword(s):  
Nitric Oxide ◽  
Shear Stress ◽  
Nitric Oxide Synthase ◽  
Signaling Pathways ◽  
Endothelial Nitric Oxide Synthase ◽  
Mesenteric Arteries ◽  
Intraluminal Pressure ◽  
Resistance Arteries ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

A potential “new player” in arteries for mediating shear stress responses is the epithelial Na+ channel (ENaC). The contribution of ENaC as shear sensor in intact arteries, and particularly different types of arteries (conduit and resistance), is unknown. We investigated the role of ENaC in both conduit (carotid) and resistance (third-order mesenteric) arteries isolated from C57Bl/6J mice. Vessel characteristics were determined at baseline (60 mmHg, no flow) and in response to increased intraluminal pressure and shear stress using a pressure myograph. These protocols were performed in the absence and presence of the ENaC inhibitor amiloride (10 µM) and after inhibition of endothelial nitric oxide synthase (eNOS) by Nω-nitro-l-arginine methyl ester (l-NAME; 100 µM). Under no-flow conditions, amiloride increased internal and external diameters of carotid (13 ± 2%, P < 0.05) but not mesenteric (0.5 ± 0.9%, P > 0.05) arteries. In response to increased intraluminal pressure, amiloride had no effect on the internal diameter of either type of artery. However, amiloride affected the stress-strain curves of mesenteric arteries. With increased shear stress, ENaC-dependent effects were observed in both arteries. In carotid arteries, amiloride augmented flow-mediated dilation (9.2 ± 5.3%) compared with control (no amiloride, 6.2 ± 3.3%, P < 0.05). In mesenteric arteries, amiloride induced a flow-mediated constriction (−11.5 ± 6.6%) compared with control (−2.2 ± 4.5%, P < 0.05). l-NAME mimicked the effect of ENaC inhibition and prevented further amiloride effects in both types of arteries. These observations indicate that ENaC contributes to shear sensing in conduit and resistance arteries. ENaC-mediated effects were associated with NO production but may involve different (artery-dependent) downstream signaling pathways. NEW & NOTEWORTHY The epithelial Na+ channel (ENaC) contributes to shear sensing in conduit and resistance arteries. In conduit arteries ENaC has a role as a vasoconstrictor, whereas in resistance arteries ENaC contributes to vasodilation. Interaction of ENaC with endothelial nitric oxide synthase/nitric oxide signaling to mediate the effects is supported; however, cross talk with other shear stress-dependent signaling pathways cannot be excluded. Listen to this article’s corresponding podcast at https://ajpheart.podbean.com/e/different-roles-of-enac-in-carotid-and-mesenteric-arteries/ .

Fetal origins of adult vascular dysfunction in mice lacking endothelial nitric oxide synthase

2005 ◽  
Vol 288 (5) ◽  
pp. R1114-R1121 ◽  
Author(s):  
Monica Longo ◽  
Venu Jain ◽  
Yuri P. Vedernikov ◽  
Radek Bukowski ◽  
Robert E. Garfield ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Vascular Function ◽  
Vascular Dysfunction ◽  
Mesenteric Arteries ◽  
Fetal Origins ◽  
Uterine Environment ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Epidemiological studies have shown increased incidence of hypertension and coronary artery disease in growth-restricted fetuses during their adult life. A novel animal model was used to test the hypothesis regarding the role of an abnormal uterine environment in fetal programming of adult vascular dysfunction. Mice lacking a functional endothelial nitric oxide synthase (NOS3−/−KO, where KO is knockout) and wild-type (WT) mice (NOS3+/+WT) were crossbred to produce homozygous NOS3−/−KO, maternally derived heterozygous (NOS3+/−mat, mother with NOS3 deficiency), paternally derived heterozygous (NOS3+/−pat, normal mother), and NOS3+/+WT litters. Number of fetuses per litter was smaller in NOS3−/−KO and NOS3+/−mat compared with NOS3+/−pat and NOS3+/+WT mice. Adult female mice from these litters (7–8 wk old) were killed, and ring preparations of carotid and mesenteric arteries were mounted in a wire myograph to evaluate the passive and reactive vascular characteristics. Slope of the length-tension plot (a measure of vascular compliance) was increased, and optimal diameter (as calculated by Laplace equation) was decreased in NOS3−/−KO and NOS3+/−mat compared with NOS3+/−pat and NOS3+/+WT mice. Acetylcholine caused vasorelaxation in NOS3+/−pat and NOS3+/+WT and contraction in NOS3−/−KO and NOS3+/−mat mice. Responses to phenylephrine and Ca2+ were increased in NOS3−/−KO and NOS3+/−mat compared with NOS3+/−pat and NOS3+/+WT mice. Relaxation to isoproterenol was decreased in NOS3−/−KO and NOS3+/−mat vs. NOS3+/−pat and NOS3+/+WT mice. Abnormalities in the passive and reactive in vitro vascular properties seen in NOS+/−mat that developed in a NOS3-deficient maternal/uterine environment compared with the genetically identical NOS3+/−pat mice that developed in a normal environment are the first direct evidence in support of a role for uterine environment in determining vascular function in later life.

Regulation of endothelial nitric oxide synthase by the actin cytoskeleton

2003 ◽  
Vol 284 (6) ◽  
pp. C1542-C1549 ◽  
Author(s):  
Yunchao Su ◽  
Sophia Edwards-Bennett ◽  
Michael R. Bubb ◽  
Edward R. Block
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Plasma Membranes ◽  
Enos Activity ◽  
Swinholide A ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Texas Red ◽  
Enos Protein

In the present study, the association of endothelial nitric oxide synthase (eNOS) with the actin cytoskeleton in pulmonary artery endothelial cells (PAEC) was examined. We found that the protein contents of eNOS, actin, and caveolin-1 were significantly higher in the caveolar fraction of plasma membranes than in the noncaveolar fraction of plasma membranes in PAEC. Immunoprecipitation of eNOS from lysates of caveolar fractions of plasma membranes in PAEC resulted in the coprecipitation of actin, and immunoprecipitation of actin from lysates of caveolar fractions resulted in the coprecipitation of eNOS. Confocal microscopy of PAEC, in which eNOS was labeled with fluorescein, F-actin was labeled with Texas red-phalloidin, and G-actin was labeled with deoxyribonuclease I conjugated with Texas red, also demonstrated an association between eNOS and F-actin or G-actin. Incubation of purified eNOS with purified F-actin and G-actin resulted in an increase in eNOS activity. The increase in eNOS activity caused by G-actin was much higher than that caused by F-actin. Incubation of PAEC with swinholide A, an actin filament disruptor, resulted in an increase in eNOS activity, eNOS protein content, and association of eNOS with G-actin and in a decrease in the association of eNOS with F-actin. The increase in eNOS activity was higher than that in eNOS protein content in swinholide A-treated cells. In contrast, exposure of PAEC to phalloidin, an actin filament stabilizer, caused decreases in eNOS activity and association of eNOS with G-actin and increases in association of eNOS with F-actin. These results suggest that eNOS is associated with actin in PAEC and that actin and its polymerization state play an important role in the regulation of eNOS activity.

Expression of endothelial nitric oxide synthase in the postnatal developing porcine kidney

2001 ◽  
Vol 280 (5) ◽  
pp. R1269-R1275 ◽  
Author(s):  
Michael J. Solhaug ◽  
Usa Kullaprawithaya ◽  
Xui Q. Dong ◽  
Ke-Wen Dong
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Protein Content ◽  
Endothelial Nitric Oxide Synthase ◽  
Enos Expression ◽  
Developmentally Regulated ◽  
Enos Mrna ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Enos Protein

The postnatal pattern of renal endothelial nitric oxide synthase (eNOS) is unknown. The purpose of this study was to characterize eNOS expression during maturation and compare this to neuronal NOS (nNOS). The experiments measured whole kidney eNOS mRNA expression by RT-PCR and protein content by Western blot, as well as cortical and medullary protein content in piglets at selected postnatal ages and in adult pigs. Whole kidney eNOS mRNA was compared with nNOS. Whole kidney eNOS expression decreased from the newborn to its lowest at 7 days, returning by 14 days to adult levels. This eNOS mRNA pattern contrasted with nNOS, which was highest at birth, and progressively decreased to its lowest level in the adult. At birth, cortical eNOS protein was greater than medullary, contrasting with the adult pattern of equivalent levels. In conclusion eNOS is developmentally regulated during early renal maturation and may critically participate in renal function during this period. The eNOS developmental pattern differs from nNOS, suggesting that these isoforms may have different regulatory factors and functional contributions in the postnatal kidney.

scholarly journals Inhibition of MEK/ERK1/2 signalling alters endothelial nitric oxide synthase activity in an agonist-dependent manner

2006 ◽  
Vol 398 (2) ◽  
pp. 279-288 ◽  
Author(s):  
Jacqueline M. Cale ◽  
Ian M. Bird
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Intracellular Trafficking ◽  
Enos Activity ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Nitric Oxide Synthase Activity

eNOS (endothelial nitric oxide synthase) activity is post-translationally regulated in a complex fashion by acylation, protein–protein interactions, intracellular trafficking and phosphorylation, among others. Signalling pathways that regulate eNOS activity include phosphoinositide 3-kinase/Akt, cyclic nucleotide-dependent kinases [PKA (protein kinase A) and PKG], PKC, as well as ERKs (extracellular-signal-regulated kinases). The role of ERKs in eNOS activation remains controversial. In the present study, we have examined the role of ERK1/2 in eNOS activation in HUVEC-CS [transformed HUVEC (human umbilical-vein endothelial cells)] as well as a widely used model for eNOS study, transiently transfected COS-7 cells. U0126 pretreatment of HUVEC-CS potentiated ATP-stimulated eNOS activity, independent of changes in intracellular Ca2+ concentration ([Ca2+]i). In COS-7 cells transiently expressing ovine eNOS, U0126 potentiated A23187-stimulated eNOS activity, but inhibited ATP-stimulated activity. Compensatory changes in phosphorylation of five key eNOS residues did not account for changes in A23187-stimulated activity. However, in the case of ATP, altered phosphorylation and changes in [Ca2+]i may partially contribute to U0126 inhibition of activity. Finally, seven eNOS alanine mutants of putative ERK1/2 targets were generated and the effects of U0126 pretreatment on eNOS activity were gauged with A23187 and ATP treatment. T97A-eNOS was the only construct significantly different from wild-type after U0126 pretreatment and ATP stimulation of eNOS activation. In the present study, eNOS activity was either potentiated or inhibited in COS-7 cells, suggesting agonist dependence for MEK/ERK1/2 signalling [where MEK is MAPK (mitogen-activated protein kinase)/ERK kinase] to eNOS and a complex mechanism including [Ca2+]i, phosphorylation and, possibly, intracellular trafficking.

scholarly journals Endothelial Nitric Oxide Synthase and Its Negative Regulator Caveolin-1 Localize to Distinct Perinuclear Organelles

2002 ◽  
Vol 50 (6) ◽  
pp. 779-788 ◽  
Author(s):  
Roland Govers ◽  
Peter van der Sluijs ◽  
Elly van Donselaar ◽  
Jan-Willem Slot ◽  
Ton J. Rabelink
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Golgi Complex ◽  
Endothelial Nitric Oxide Synthase ◽  
Direct Interaction ◽  
Negative Regulator ◽  
Caveolin 1 ◽  
Enos Activity ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Caveolin-1 is a member of a subset of intracellular proteins that regulate endothelial nitric oxide synthase (eNOS) activity. In caveolae, caveolin-1 inhibits eNOS activity via a direct interaction with the enzyme. Previous work has indicated that both eNOS and caveolin-1 are also localized at the perinuclear Golgi complex. Whether caveolin-1 is involved in eNOS regulation in this cell compartment is unknown. Here we studied the localization of eNOS and caveolin-1 in the perinuclear region of primary bovine aortic endothelial cells. By immunofluorescence microscopy we show that both eNOS and caveolin-1 co-localize with Golgi markers. On treatment of the cells with the microtubule-depolymerizing drug nocodazole, the Golgi complex is scattered and caveolin-1 is found in vesicles at the periphery of the cell, while eNOS is localized at large structures near the nucleus. The nocodazole-induced redistribution of eNOS is similar to that of cis-, medial-, and trans-Golgi markers, while the caveolin-1 redistribution resembles that of sec22, a marker for the intermediate compartment. The localization of eNOS and caveolin-1 at distinct perinuclear compartments that behave differently in the presence of nocodazole indicates that eNOS activity is not regulated by caveolin-1 in the Golgi complex.

scholarly journals Locally Different Endothelial Nitric Oxide Synthase Protein Levels in Ascending Aortic Aneurysms of Bicuspid and Tricuspid Aortic Valve

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Salah A. Mohamed ◽  
Arlo Radtke ◽  
Roza Saraei ◽  
Joern Bullerdiek ◽  
Hajar Sorani ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Aortic Valve ◽  
Endothelial Nitric Oxide Synthase ◽  
Aortic Aneurysms ◽  
Tricuspid Aortic Valve ◽  
Protein Levels ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Enos Protein

Aims. Dysregulated expression of the endothelial nitric oxide synthase (eNOS) is observed in aortic aneurysms associated with bicuspid aortic valve (BAV). We determined eNOS protein levels in various areas in ascending aortic aneurysms.Methods and Results. Aneurysmal specimens were collected from 19 patients, 14 with BAV and 5 with tricuspid aortic valve (TAV). ENOS protein levels were measured in the outer curve (convexity), the opposite side (concavity), the distal and above the sinotubular junction (proximal) aneurysm. Cultured aortic cells were treated with NO synthesis inhibitor L-NAME and the amounts of 35 apoptosis-related proteins were determined. In patients with BAV, eNOS levels were significantly lower in the proximal aorta than in the concavity and distal aorta. ENOS protein levels were also lower in the convexity than in the concavity. While the convexity and distal aorta showed similar eNOS protein levels in BAV and TAV patients, levels were higher in TAV proximal aorta. Inhibition of NO synthesis in aneurysmal aortic cells by L-NAME led to a cytosolic increase in the levels of mitochondrial serine protease HTRA2/Omi.Conclusion. ENOS protein levels were varied at different areas of the aneurysmal aorta. The dysregulation of nitric oxide can lead to an increase in proapoptotic HTRA2/Omi.

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