Diabetic HDL-associated myristic acid inhibits acetylcholine-induced nitric oxide generation by preventing the association of endothelial nitric oxide synthase with calmodulin

2008 ◽  
Vol 294 (1) ◽  
pp. C295-C305 ◽  
Author(s):  
James White ◽  
Theresa Guerin ◽  
Hollie Swanson ◽  
Steven Post ◽  
Haining Zhu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Myristic Acid ◽  
Acetylcholine Receptors ◽  
Diabetic Mouse ◽  
No Synthase ◽  
Diabetic Patients ◽  
No Production ◽  
Dependent Manner ◽  
Endothelial No Synthase ◽  
Stimulation Of

In the current study, we examined whether diabetes affected the ability of HDL to stimulate nitric oxide (NO) production. Using HDL isolated from both diabetic humans and diabetic mouse models, we found that female HDL no longer induced NO synthesis, despite containing equivalent amounts of estrogen as nondiabetic controls. Furthermore, HDL isolated from diabetic females and males prevented acetylcholine-induced stimulation of NO generation. Analyses of both the human and mouse diabetic HDL particles showed that the HDLs contained increased levels of myristic acid. To determine whether myristic acid associated with HDL particles was responsible for the decrease in NO generation, myristic acid was added to HDL isolated from nondiabetic humans and mice. Myristic acid-associated HDL inhibited the generation of NO in a dose-dependent manner. Importantly, diabetic HDL did not alter the levels of endothelial NO synthase or acetylcholine receptors associated with the cells. Surprisingly, diabetic HDL inhibited ionomycin-induced stimulation of NO production without affecting ionomycin-induced increases in intracellular calcium. Further analysis indicated that diabetic HDL prevented calmodulin from interacting with endothelial NO synthase (eNOS) but did not affect the activation of calmodulin kinase or calcium-independent mechanisms for stimulating eNOS. These studies are the first to show that a specific fatty acid associated with HDL inhibits the stimulation of NO generation. These findings have important implications regarding cardiovascular disease in diabetic patients.

17β-Estradiol decreases hypoxic induction of erythropoietin gene expression

2002 ◽  
Vol 283 (2) ◽  
pp. R496-R504 ◽  
Author(s):  
Harshini Mukundan ◽  
Thomas C. Resta ◽  
Nancy L. Kanagy
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Oxygen Delivery ◽  
Chronic Hypoxia ◽  
No Synthase ◽  
No Production ◽  
Enos Expression ◽  
Hypoxic Induction ◽  
Endothelial No Synthase ◽  
17Β Estradiol

Exposure to chronic hypoxia induces erythropoietin (EPO) production to facilitate oxygen delivery to hypoxic tissues. Previous studies from our laboratory found that ovariectomy (OVX) exacerbates the polycythemic response to hypoxia and treatment with 17β-estradiol (E2-β) inhibits this effect. We hypothesized that E2-β decreases EPO gene expression during hypoxia. Because E2-β can induce nitric oxide (NO) production and NO can attenuate EPO synthesis, we further hypothesized that E2-β inhibition of EPO gene expression is mediated by NO. These hypotheses were tested in OVX catheterized rats treated with E2-β (20 μg/day) or vehicle for 14 days and exposed to 8 or 12 h of hypoxia (12% O2) or normoxia. We found that E2-β treatment significantly decreased EPO synthesis and gene expression during hypoxia. E2-β treatment did not induce endothelial NO synthase (eNOS) expression in the kidney but potentiated hypoxia-induced increases in plasma nitrates. We conclude that E2-β decreases hypoxic induction of EPO. However, this effect does not appear to be related to changes in renal eNOS expression.

Stimulation of nitric oxide from muscle cells by VIP: prejunctional enhancement of VIP release

1992 ◽  
Vol 262 (4) ◽  
pp. G774-G778 ◽  
Author(s):  
J. R. Grider ◽  
K. S. Murthy ◽  
J. G. Jin ◽  
G. M. Makhlouf
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Muscle Cells ◽  
No Synthase ◽  
No Production ◽  
Field Stimulation ◽  
Relaxant Effect ◽  
Gastric Muscle ◽  
Synthase Inhibitor ◽  
Stimulation Of

The source of nitric oxide (NO) and its role in neurally induced relaxation was examined in smooth muscle of the stomach and tenia coli. Field stimulation of gastric muscle strips was accompanied by frequency-dependent relaxation, vasoactive intestinal peptide (VIP) release, and NO production: the NO synthase inhibitor, NG-nitro-L-arginine (L-NNA) completely inhibited NO production and partly inhibited VIP release (52-54%) and relaxation (58-88%); inhibition of all three functions was reversed by L-arginine but not by D-arginine. In isolated gastric muscle cells, VIP caused relaxation and stimulated NO production: L-NNA completely inhibited NO production and partly inhibited relaxation; the inhibition was reversed by L-arginine but not by D-arginine. Abolition of NO production with only partial inhibition of relaxation implied that NO production from muscle cells induced by the action of VIP was partly responsible for relaxation. By contrast, field stimulation of tenia coli was accompanied by relaxation and VIP release but not by NO production. Neither VIP release nor relaxation was affected by L-NNA. In isolated muscle cells of tenia coli, VIP caused relaxation but did not stimulate NO production; relaxation in these cells was not affected by L-NNA. We conclude that 1) VIP is the primary relaxant transmitter in both gastric muscle and tenia coli, 2) the release of VIP in gastric muscle but not in tenia coli stimulates NO production from target muscle cells, and 3) NO amplifies the relaxant effect of VIP in muscle cells and acts presynaptically to enhance the release of VIP.

Direct and reversible inhibition of endothelial nitric oxide synthase by nitric oxide

1995 ◽  
Vol 268 (6) ◽  
pp. H2216-H2223 ◽  
Author(s):  
L. V. Ravichandran ◽  
R. A. Johns ◽  
A. Rengasamy
Keyword(s):  
Nitric Oxide ◽  
Enzyme Activity ◽  
Feedback Mechanism ◽  
No Synthase ◽  
Maximal Velocity ◽  
Dependent Manner ◽  
Reversible Inhibition ◽  
Endothelial No Synthase ◽  
Endothelial Nitric Oxide

The objective of this study was to investigate the regulation of endothelial nitric oxide (NO) synthase by NO. Partially purified endothelial NO synthase was exposed to authentic NO (10-200 microM) and to the nitrovasodilators sodium nitroprusside (SNP; 10-1,000 microM) and S-nitroso-N-acetylpenicillamine (SNAP; 100-1,000 microM), and enzyme activity was assayed by measuring the conversion of L-[3H]arginine to L-[3H]citrulline in the presence of added cofactors. NO, SNP, and SNAP inhibited NO synthase activity in a dose-dependent manner, NO being the most potent inhibitor. The Michaelis constant for L-arginine was not altered (4.87 microM) by NO (50 microM), whereas the maximal velocity of the enzyme decreased from 784 to 633 pmol.mg-1.min-1. Oxyhemoglobin (10 microM) partially prevented the inhibition of NO synthase by NO (50 microM). The data also suggest that NO inhibits endothelial NO synthase activity by directly interacting with the NO synthase and not by an indirect mechanism such as limitation of cofactor or oxygen availability. Dialysis of NO synthase treated with NO (50 microM) partially restored the enzyme activity. This study demonstrates a direct and reversible inhibition of NO synthase by NO, suggesting a feedback mechanism in vivo.

scholarly journals Nitric Oxide is Produced by Cowdria ruminantium-Infected Bovine Pulmonary Endothelial Cells In Vitro and Is Stimulated by Gamma Interferon

1998 ◽  
Vol 66 (5) ◽  
pp. 2115-2121 ◽  
Author(s):  
Mbithe Mutunga ◽  
Patricia M. Preston ◽  
Keith J. Sumption
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
No Synthase ◽  
No Production ◽  
Dependent Manner ◽  
Donor Molecule ◽  
No Donor ◽  
Pulmonary Endothelial Cells ◽  
Cowdria Ruminantium ◽  
Dose Dependent

ABSTRACT Nitric oxide (NO) is a labile inorganic free radical produced by NO synthase from the substrate l-arginine in various cells and tissues including endothelial cells. A substantial elevation of nitrite levels indicative of NO production occurred in cultures ofCowdria ruminantium-infected bovine pulmonary endothelial cells (BPEC) incubated in medium alone. Exposure of the infected cultures to recombinant bovine gamma interferon (BorIFN-γ) resulted in more rapid production of NO, reduced viability of C. ruminantium, and induction of endothelial cell death. Significant inhibition of NO production was noted after addition of the NO synthase inhibitor N-monomethyl-l-arginine (l-NMMA), indicating that the increase in production occurred via the inducible NO synthase pathway. Reduction in the infectivity of C. ruminantium elementary bodies (EBs) occurred in a dose-dependent manner after incubation with the NO donor moleculeS-nitroso-N-acetyl-dl-penicillamine (SNAP) prior to infection of endothelial cells. The level of infection in cultures maintained in SNAP was reduced in a dose-dependent manner with significant negative correlation between the final level of infection on day 7 and the level of SNAP (r = −0.96). It was established that pretreatment and cultivation of C. ruminantium EBs with the NO donor molecule SNAP reduced infectivity to cultures and viability of EBs with the implication that release of NO in vivo following infection of endothelial cells may have an effect upon the multiplication of the agent in the host animal and may be involved in the pathogenesis of heartwater through the effect of this molecule upon circulation.

scholarly journals Stimulation of Nitric Oxide Production in Macrophages by Babesia bovis

1998 ◽  
Vol 66 (9) ◽  
pp. 4130-4136 ◽  
Author(s):  
Roger W. Stich ◽  
Lisl K. M. Shoda ◽  
Miriam Dreewes ◽  
Barbara Adler ◽  
Thomas W. Jungi ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Babesia Bovis ◽  
Biologically Active ◽  
Supernatant Fraction ◽  
No Production ◽  
Dependent Manner ◽  
Ifn Γ ◽  
Vitro Effect ◽  
Culture Supernatants ◽  
Stimulation Of

ABSTRACT Gamma interferon (IFN-γ)-activated macrophages are believed to play a key role in resistance to Babesia bovis through parasite suppression by macrophage secretory products. However, relatively little is known about interactions between this intraerythrocytic parasite and the macrophages of its bovine host. In this study, we examined the in vitro effect of intact and fractionatedB. bovis merozoites on bovine macrophage nitric oxide (NO) production. In the presence of IFN-γ, B. bovis merozoites stimulated NO production, as indicated by the presence of increasedl-arginine-dependent nitrite (NO2 −) levels in culture supernatants of macrophages isolated from several cattle. The merozoite crude membrane (CM) fraction stimulated greater production of NO, in a dose-dependent manner, than did the merozoite homogenate or the soluble, cytosolic high-speed supernatant fraction. Stimulation of NO production by CM was enhanced by as little as 1 U of IFN-γ per ml of culture medium. Upregulation of inducible NO synthase mRNA in bovine macrophages by either B. bovis-parasitized erythrocytes and IFN-γ or CM was also observed. B. bovis-specific T-helper lymphocyte culture supernatants, all of which contained IFN-γ, were also found to induce l-arginine-dependent NO2 − production. Supernatants that induced the highest levels of NO also contained biologically active TNF. These results show that B. bovis merozoites and antigen-stimulated B. bovis-immune T cells can induce the production of NO, a molecule implicated in both protection and pathologic changes associated with hemoprotozoan parasite infections.

Interaction between endogenously produced carbon monoxide and nitric oxide in regulation of renal afferent arterioles

2006 ◽  
Vol 291 (6) ◽  
pp. H2772-H2778 ◽  
Author(s):  
Fady T. Botros ◽  
L. Gabriel Navar
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Soluble Guanylate Cyclase ◽  
No Synthase ◽  
No Production ◽  
Heme Oxygenases ◽  
Juxtamedullary Nephron ◽  
Calcium Activated Potassium Channels ◽  
Afferent Arterioles ◽  
Stimulation Of

Heme oxygenases (HO-1 and HO-2) catalyze the conversion of heme to carbon monoxide (CO), iron, and biliverdin. CO causes vasorelaxation via stimulation of soluble guanylate cyclase (sGC) and/or activation of calcium-activated potassium channels. Because nitric oxide (NO) exerts effects via the same pathways, we tested the interaction between CO and NO on rat afferent arterioles (AAs) using the blood-perfused juxtamedullary nephron preparation. AAs were superfused with either tricarbonyldichlororuthenium (II) dimer, known as CO releasing molecule (CORM-2), 10 μmol/l CO solution, or 15 μmol/l chromium mesoporphyrin (CrMP, HO inhibitor). AAs were also superfused with 1 mmol/l Nω-nitro-l-arginine (l-NNA) to inhibit NO synthase (NOS) or 10 μmol/l 1 H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one to inhibit sGC, and then CrMP was superfused during NOS inhibition or sGC inhibition. Treatment with 150 and 300 μmol/l CORM-2 or with CO (10 μmol/l) significantly dilated AAs (22.0 ± 0.9 and 22.8 ± 0.9 vs. 18.3 ± 0.9 μm, n = 5, P < 0.05; and 26.0 ± 1.4 vs. 18.8 ± 0.7 μm, n = 5, P < 0.05). In untreated vessels, HO inhibition did not alter AA diameter (17.5 ± 0.7 vs. 17.2 ± 0.6 μm, n = 7, P > 0.05); however, during inhibition of NO production, which constricted arterioles to 14.6 ± 1.2 μm, n = 6, P < 0.05, concurrent HO inhibition led to further vasoconstriction (11.7 ± 1.6 μm, n = 6, P < 0.05). CORM-2 attenuated the l-NNA-induced vasoconstriction. Inhibition of sGC caused significant constriction (15.7 ± 0.4 vs. 18.8 ± 0.4 μm, n = 6, P < 0.05). HO inhibition during sGC inhibition did not cause further change in AAs (15.5 ± 0.7 μm, n = 6). We conclude that endogenously produced CO does not exert a perceptible influence on AA diameter in the presence of intact NO system; however, when NO production is inhibited, CO serves as an important renoprotective reserve mechanism to prevent excess afferent arteriolar constriction.

scholarly journals Rise in endothelium-derived NO after stimulation of rat perivascular sympathetic mesenteric nerves

1999 ◽  
Vol 277 (3) ◽  
pp. H1027-H1035 ◽  
Author(s):  
Mauricio P. Boric ◽  
Xavier F. Figueroa ◽  
M. Verónica Donoso ◽  
Alfonso Paredes ◽  
Inés Poblete ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Electrical Stimulation ◽  
Sympathetic Activity ◽  
Perfusion Pressure ◽  
Stimulus Frequency ◽  
No Synthase ◽  
No Production ◽  
No Release ◽  
Perivascular Nerves ◽  
Stimulation Of

To evaluate whether sympathetic activity induces nitric oxide (NO) production, we perfused the rat arterial mesenteric bed and measured luminally accessible norepinephrine (NE), NO, and cGMP before, during, and after stimulation of perivascular nerves. Electrical stimulation (1 min, 30 Hz) raised perfusion pressure by 97 ± 7 mmHg, accompanied by peaks of 23 ± 3 pmol NE, 445 ± 48 pmol NO, and 1 pmol cGMP. Likewise, perfusion with 10 μM NE induced vasoconstriction coupled to increased NO and cGMP release. Electrically elicited NO release depended on stimulus frequency and duration. Endothelium denudation with saponin abolished the NO peak without changing NE release. Inhibition of NO synthase with 100 μM N ω-nitro-l-arginine reduced basal NO and cGMP release and blocked the electrically stimulated and exogenous NE-stimulated NO peak while enhancing vasoconstriction. Blocking either sympathetic exocytosis with 1 μM guanethidine or α1-adrenoceptors with 30 nM prazosin abolished the electrically evoked vasoconstriction and NO release. α2-Adrenoceptor blockade with 1 μM yohimbine reduced both vasoconstriction and NO peak while increasing NE release. In summary, sympathetically released NE induces vasoconstriction, which triggers a secondary release of endothelial NO coupled to cGMP production.

scholarly journals Protein kinase B/Akt activates c-Jun NH2-terminal kinase by increasing NO production in response to shear stress

2001 ◽  
Vol 91 (4) ◽  
pp. 1574-1581 ◽  
Author(s):  
Young-Mi Go ◽  
Yong Chool Boo ◽  
Heonyong Park ◽  
Matthew C. Maland ◽  
Rakesh Patel ◽  
...  
Keyword(s):  
Shear Stress ◽  
Protein Kinase ◽  
Transient Expression ◽  
Protein Kinase B ◽  
No Synthase ◽  
No Production ◽  
Endothelial No Synthase ◽  
Jnk Activation ◽  
Adenoviral Construct ◽  
Stimulation Of

Laminar shear stress activates c-Jun NH2-terminal kinase (JNK) by the mechanisms involving both nitric oxide (NO) and phosphatidylinositide 3-kinase (PI3K). Because protein kinase B (Akt), a downstream effector of PI3K, has been shown to phosphorylate and activate endothelial NO synthase, we hypothesized that Akt regulates shear-dependent activation of JNK by stimulating NO production. Here, we examined the role of Akt in shear-dependent NO production and JNK activation by expressing a dominant negative Akt mutant (AktAA) and a constitutively active mutant (AktMyr) in bovine aortic endothelial cells (BAEC). As expected, pretreatment of BAEC with the PI3K inhibitor (wortmannin) prevented shear-dependent stimulation of Akt and NO production. Transient expression of AktAA in BAEC by using a recombinant adenoviral construct inhibited the shear-dependent stimulation of NO production and JNK activation. However, transient expression of AktMyr by using a recombinant adenoviral construct did not induce JNK activation. This is consistent with our previous finding that NO is required, but not sufficient on its own, to activate JNK in response to shear stress. These results and our previous findings strongly suggest that shear stress triggers activation of PI3K, Akt, and endothelial NO synthase, leading to production of NO, which (along with O[Formula: see text], which is also produced by shear) activates Ras-JNK pathway. The regulation of Akt, NO, and JNK by shear stress is likely to play a critical role in its antiatherogenic effects.

scholarly journals Bradykinin stimulation of nitric oxide production is not sufficient for gamma-globin induction

2014 ◽  
Vol 142 (3-4) ◽  
pp. 189-196 ◽  
Author(s):  
Vladan Cokic ◽  
Tijana Suboticki ◽  
Bojana Beleslin-Cokic ◽  
Milos Diklic ◽  
Pavle Milenkovic ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Globin Gene ◽  
No Production ◽  
Dependent Manner ◽  
Erythroid Progenitors ◽  
Globin Gene Expression ◽  
Stimulation Of

Introduction. Hydroxycarbamide, used in therapy of hemoglobinopathies, enhances nitric oxide (NO) production both in primary human umbilical vein endothelial cells (HUVECs) and human bone marrow endothelial cell line (TrHBMEC). Moreover, NO increases ?-globin and fetal hemoglobin levels in human erythroid progenitors. Objective. In order to find out whether simple physiologic stimulation of NO production by components of hematopoietic microenvironment can increase ?-globin gene expression, the effects of NO-inducer bradykinin were examined in endothelial cells. Methods. The study was performed in co-cultures of human erythroid progenitors, TrHBMEC and HUVECs by ozone-based chemiluminescent determination of NO and real-time quantitative RT-PCR. Results. In accordance with previous reports, the endogenous factor bradykinin increased endothelial cell production of NO in a dose- and time-dependent manner (0.1-0.6 ?M up to 30 minutes). This induction of NO in HUVECs and TrHBMEC by bradykinin was blocked by competitive inhibitors of NO synthase (NOS), demonstrating NOS-dependence. It has been shown that bradykinin significantly reduced endothelial NOS (eNOS) mRNA level and eNOS/?-actin ratio in HUVEC (by twofold). In addition, bradykinin failed to increase ?-globin mRNA expression in erythroid progenitors only, as well as in co-culture studies of erythroid progenitors with TrHBMEC and HUVEC after 24 hours of treatment. Furthermore, bradykinin did not induce ?/? globin ratio in erythroid progenitors in co-cultures with HUVEC. Conclusion. Bradykinin mediated eNOS activation leads to short time and low NO production in endothelial cells, insufficient to induce ?-globin gene expression. These results emphasized the significance of elevated and extended NO production in augmentation of ?-globin gene expression.

SOME ASPECTS OF MECHANISM OF SUCCINAMIDES INFLUENCE ON METABOLIC HOMEOSTASIS OF THE ORGANISM

2018 ◽  
pp. 27-31
Author(s):  
I. A. Palagina
Keyword(s):  
Nitric Oxide ◽  
Biological Activity ◽  
Antioxidant System ◽  
No Synthase ◽  
Antioxidant Potential ◽  
Metabolic Homeostasis ◽  
Energetic Metabolism ◽  
Complex Action ◽  
Energy Processes ◽  
Stimulation Of

Succinate containing compounds possess many types of biological activity and are used for the development of drugs with the target and complex action. This paper is devoted to some aspects of the mechanism of succinamides’ action in a dose of 100 mg/kg. We studied the influence of the compound with antidiabetic properties, -phenylethylamide of 2-oxysuccinanyl acid ( -PhEA-OSAA), and its metabolites such as 2-hydroxyphenylsuccinamide (2-HPhSA) and β-phenylethylsuccinamide ( -PhESA) on the marker indicators of energetic metabolism (EM), antioxidant system (AOS) and nitric oxide (NO) metabolism in subacute experiment on rats. Studies have shown that the action of -FEA-OSAKA on metabolic homeostasis is realized through stimulation of EM, reduction of intensity of NO-synthase metabolism and weakening of the AOS. The nature of the action of -FES and 2-GFS, taking into account the indicators of the state of homeostasis, largely coincides with β-FEA-OSAKA. It was found that the key links in the mechanism of toxic action of succinamides are the effect on antioxidant potential, NO metabolism and energy processes.

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