scholarly journals Hypoxia Increases Nitric Oxide-Dependent Inhibition of Angiogenic Growth

2021 ◽  
Vol 1 (3) ◽  
pp. 366-380
Author(s):  
Cristina Arce ◽  
Diana Vicente ◽  
Fermí Monto ◽  
Laura González ◽  
Cristina Nuñez ◽  
...  

Nitric oxide (NO) is a proangiogenic factor acting through the soluble guanylate cyclase (sGC) pathway. However, angiogenic growth increases energy demand, which may be hampered by NO inhibition of cytochrome c oxidase (CcO). Then, NO activity would be the balanced result of sGC activation (pro-angiogenic) and CcO inhibition (anti-angiogenic). NO activity in a rat and eNOS−/− mice aortic ring angiogenic model and in a tube formation assay (human aortic endothelial cells) were analyzed in parallel with mitochondrial O2 consumption. Studies were performed with NO donor (DETA-NO), sGC inhibitor (ODQ), and NOS or nNOS inhibitors (L-NAME or SMTC, respectively). Experiments were performed under different O2 concentrations (0–21%). Key findings were: (i) eNOS-derived NO inhibits angiogenic growth by a mechanism independent on sGC pathway and related to inhibition of mitochondrial O2 consumption; (ii) NO inhibition of the angiogenic growth is more evident in hypoxic vessels; (iii) in the absence of eNOS-derived NO, the modulation of angiogenic growth, related to hypoxia, disappears. Therefore, NO, but not lower O2 levels, decreases the angiogenic response in hypoxia through competitive inhibition of CcO. This anti-angiogenic activity could be a promising target to impair pathological angiogenesis in hypoxic conditions, as it occurs in tumors or ischemic diseases.

2003 ◽  
Vol 285 (2) ◽  
pp. L296-L304 ◽  
Author(s):  
Christopher J. Mingone ◽  
Sachin A. Gupte ◽  
Takafumi Iesaki ◽  
Michael S. Wolin

Nitric oxide (NO) donors generally relax vascular preparations through cGMP-mediated mechanisms. Relaxation of endothelium-denuded bovine pulmonary arteries (BPA) and coronary arteries to the NO donor S-nitroso- N-acetyl-penicillamine (SNAP) is almost eliminated by inhibition of soluble guanylate cyclase activation with 10 μM 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), whereas only a modest inhibition of relaxation is observed under hypoxia (PO2 = 8–10 Torr). This effect of hypoxia is independent of the contractile agent used and is also observed with NO gas. ODQ eliminated SNAP-induced increases in cGMP under hypoxia in BPA. cGMP-independent relaxation of BPA to SNAP was not attenuated by inhibition of K+ channels (10 mM tetraethylammonium), myosin light chain phosphatase (0.5 μM microcystin-LR), or adenylate cyclase (4 μM 2′,5′-dideoxyadenosine). SNAP relaxed BPA contracted with serotonin under Ca2+-free conditions in the presence of hypoxia and ODQ, and contraction to Ca2+ readdition was also attenuated. The sarcoplasmic reticulum Ca2+-reuptake inhibitor cyclopiazonic acid (0.2 mM) attenuated SNAP-mediated relaxation of BPA in the presence of ODQ. Thus hypoxic conditions appear to promote a cGMP-independent relaxation of BPA to NO by enhancing sarcoplasmic reticulum Ca2+ reuptake.


2007 ◽  
Vol 292 (2) ◽  
pp. H893-H903 ◽  
Author(s):  
Galina N. Antonova ◽  
Connie M. Snead ◽  
Alexander S. Antonov ◽  
Christiana Dimitropoulou ◽  
Richard C. Venema ◽  
...  

Large (pathological) amounts of nitric oxide (NO) induce cell injury, whereas low (physiological) NO concentrations often ameliorate cell injury. We tested the hypotheses that pretreatment of endothelial cells with low concentrations of NO (preconditioning) would prevent injury induced by high NO concentrations. Apoptosis, induced in bovine aortic endothelial cells (BAECs) by exposing them to either 4 mM sodium nitroprusside (SNP) or 0.5 mM N-(2-aminoethyl)- N-(2-hydroxy-2-nitrosohydrazino)-1,2-ethylenediamine (spermine NONOate) for 8 h, was abolished by 24-h pretreatment with either 100 μM SNP, 10 μM spermine NONOate, or 100 μM 8-bromo-cGMP (8-Br-cGMP). Repair of BAECs following wounding, measured as the recovery rate of transendothelial electrical resistance, was delayed by 8-h exposure to 4 mM SNP, and this delay was significantly attenuated by 24-h pretreatment with 100 μM SNP. NO preconditioning produced increased association and expression of soluble guanyl cyclase (sGC) and heat shock protein 90 (HSP90). The protective effect of NO preconditioning, but not the injurious effect of 4 mM SNP, was abolished by either a sGC activity inhibitor 1H-[1,2,4]oxadiazolo-[4,3- a]quinoxalin-1-one (ODQ) or a HSP90 binding inhibitor (radicicol) and was mimicked by 8-Br-cGMP. We conclude that preconditioning with a low dose of NO donor accelerates repair and maintains endothelial integrity via a mechanism that includes the HSP90/sGC pathway. HSP90/sGC may thus play a role in the protective effects of NO-generating drugs from injurious stimuli.


2004 ◽  
Vol 286 (5) ◽  
pp. L984-L991 ◽  
Author(s):  
Lisa K. Kelly ◽  
Stephen Wedgwood ◽  
Robin H. Steinhorn ◽  
Stephen M. Black

The use of exogenous nitric oxide (NO) has been shown to alter the regulation of other endothelially derived mediators of vascular tone, such as endothelin-1 (ET-1). However, the interaction between NO and ET-1 appears to be complex and remains incompletely understood. One of the major actions of NO is the activation of soluble guanylate cyclase (sGC) with the subsequent generation of cGMP. Therefore, we undertook this study to test the hypothesis that NO regulates ET-1 production via the activation of the sGC/cGMP pathway. The results obtained indicated that the exposure of primary cultures of 4-wk-old ovine pulmonary arterial endothelial cells (4-wk PAECs) to the long-acting NO donor DETA NONOate induced both a dose- and time-dependent decrease in secreted ET-1. This decrease in ET-1 secretion occurred in the absence of changes in endothelin-converting enzyme-1 or sGC expression but in conjunction with a decrease in prepro-ET-1 mRNA. The changes in ET-1 release were inversely proportional to the cellular cGMP content. Furthermore, the NO-independent activator of sGC, YC-1, or treatment with a cGMP analog also produced significant decreases in ET-1 secretion. Conversely, pretreatment with the sGC inhibitor ODQ blocked the NO-induced decrease in ET-1. Therefore, we conclude that exposure of 4-wk PAECs to exogenous NO decreases secreted ET-1 resulting from the activation of sGC and increased cGMP generation.


2003 ◽  
Vol 284 (5) ◽  
pp. C1140-C1148 ◽  
Author(s):  
Richard Weller ◽  
Ann Schwentker ◽  
Timothy R. Billiar ◽  
Yoram Vodovotz

Nitric oxide (NO) can either prevent or promote apoptosis, depending on cell type. In the present study, we tested the hypothesis that NO suppresses ultraviolet B radiation (UVB)-induced keratinocyte apoptosis both in vitro and in vivo. Irradiation with UVB or addition of the NO synthase (NOS) inhibitor N G-nitro-l-arginine methyl ester (l-NAME) increased apoptosis in the human keratinocyte cell line CCD 1106 KERTr, and apoptosis was greater when the two agents were given in combination. Addition of the chemical NO donor S-nitroso- N-acetyl-penicillamine (SNAP) immediately after UVB completely abrogated the rise in apoptosis induced by l-NAME. An adenoviral vector expressing human inducible NOS (AdiNOS) also reduced keratinocyte death after UVB. Caspase-3 activity, an indicator of apoptosis, doubled in keratinocytes incubated with l-NAME compared with the inactive isomer, d-NAME, and was reduced by SNAP. Apoptosis was also increased on addition of 1,H-[1,2,4]oxadiazolo[4,3- a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase. Mice null for endothelial NOS (eNOS) exhibited significantly higher apoptosis than wild-type mice both in the dermis and epidermis, whereas mice null for inducible NOS (iNOS) exhibited more apoptosis than wild-type mice only in the dermis. These results demonstrate an antiapoptotic role for NO in keratinocytes, mediated by cGMP, and indicate an antiapoptotic role for both eNOS and iNOS in skin damage induced by UVB.


2003 ◽  
Vol 81 (2) ◽  
pp. 105-113 ◽  
Author(s):  
Xiaohong Tracey Gan ◽  
Subrata Chakrabarti ◽  
Morris Karmazyn

Endothelin-1 (ET-1) and nitric oxide (NO) exert opposite effects in the cardiovascular system, and there is evidence that the NO counters the potential deleterious effects of ET-1. We investigated whether NO affects the increased mRNA expression of ET-1 and endothelin receptors induced by (i) 30 min of ischemia with or without 30 min reperfusion in myocytes from isolated rat hearts or (ii) ischemic conditions (acidosis or hypoxia) in cultured rat neonatal ventricular myocytes. Ischemia with or without reperfusion produced more than a twofold increase in mRNA expression of ET-1 as well as the ETAand ETBreceptor (P < 0.05), although these effects were completely blocked by the NO donor 3-morpholinosydnonimine (SIN-1; 1 μM). To assess the possible factors regulating ET expression, myocytes were exposed to acidosis (pH 6.8–6.2) or to hypoxic conditions in an anaerobic chamber for 24 h in the presence or absence of SIN-1. At all acidic pHs, ET-1 and ETAreceptor mRNA expression was significantly (P < 0.05) elevated approximately threefold, although the magnitude of elevation was independent of the degree of acidosis. These effects were completely prevented by SIN-1. ETBreceptor expression was unaffected by acidosis. Hypoxia increased ET-1 as well as ETAand ETBreceptor expression threefold (P < 0.05), although this was unaffected by SIN-1. Our results demonstrate that myocardial ischemia and reperfusion upregulate the ET system, which is inhibited by NO. Although increased expression of the ET system can be mimicked by both acidosis and hypoxia, only the effects of the former are NO sensitive. NO may serve an endogenous inhibitory factor which regulates the expression of the ET system under pathological conditions.Key words: ET-1, ET receptors, NO, neonatal rat ventricular myocytes, hypoxia, acidosis.


2011 ◽  
Vol 300 (5) ◽  
pp. C979-C988 ◽  
Author(s):  
Huafang Wang ◽  
Yunchao Su

Nitric oxide (NO) mediates endothelial angiogenesis via inducing the expression of integrin αvβ3. During angiogenesis, endothelial cells adhere to and migrate into the extracellular matrix through integrins. Collagen IV binds to integrin αvβ3, leading to integrin activation, which affects a number of signaling processes in endothelial cells. In the present study, we evaluated the role of collagen IV in NO-induced angiogenesis. We found that NO donor 2,2′-(hydroxynitrosohydrazino)bis-ethanamine (NOC-18) causes increases in collagen IV mRNA and protein in lung endothelial cells and collagen IV release into the medium. Addition of collagen IV into the coating of endothelial culture increases endothelial monolayer wound repair, proliferation, and tube formation. Inhibition of collagen IV synthesis using gene silencing attenuates NOC-18-induced increases in monolayer wound repair, cell proliferation, and tube formation as well as in the phosphorylation of focal adhesion kinase (FAK). Integrin blocking antibody LM609 prevents NOC-18-induced increase in endothelial monolayer wound repair. Inhibition of protein kinase G (PKG) using the specific PKG inhibitor KT5823 or PKG small interfering RNA prevents NOC-18-induced increases in collagen IV protein and mRNA and endothelial angiogenesis. Together, these results indicate that NO promotes collagen IV synthesis via a PKG signaling pathway and that the increase in collagen IV synthesis contributes to NO-induced angiogenesis of lung endothelial cells through integrin-FAK signaling. Manipulation of collagen IV could be a novel approach for the prevention and treatment of diseases such as alveolar capillary dysplasia, severe pulmonary arterial hypertension, and tumor invasion.


Reproduction ◽  
2011 ◽  
Vol 141 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Erica Miraglia ◽  
Federico De Angelis ◽  
Elena Gazzano ◽  
Hossain Hassanpour ◽  
Angela Bertagna ◽  
...  

Nitric oxide (NO), a modulator of several physiological processes, is involved in different human sperm functions. We have investigated whether NO may stimulate the motility of human spermatozoa via activation of the soluble guanylate cyclase (sGC)/cGMP pathway. Sperm samples obtained by masturbation from 70 normozoospermic patients were processed by the swim-up technique. The kinetic parameters of the motile sperm-rich fractions were assessed by computer-assisted sperm analysis. After a 30–90 min incubation, the NO donor S-nitrosoglutathione (GSNO) exerted a significant enhancing effect on progressive motility (77, 78, and 78% vs 66, 65, and 62% of the control at the corresponding time), straight linear velocity (44, 49, and 48 μm/s vs 34, 35, and 35.5 μm/s), curvilinear velocity (81, 83, and 84 μm/s vs 68 μm/s), and average path velocity (52, 57, and 54 μm/s vs 40, 42, and 42 μm/s) at 5 μM but not at lower concentrations, and in parallel increased the synthesis of cGMP. A similar effect was obtained with the NO donor spermine NONOate after 30 and 60 min. The GSNO-induced effects on sperm motility were abolished by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (a specific sGC inhibitor) and mimicked by 8-bromo-cGMP (8-Br-cGMP; a cell-permeating cGMP analog); the treatment with Rp-8-Br-cGMPS (an inhibitor of cGMP-dependent protein kinases) prevented both the GSNO- and the 8-Br-cGMP-induced responses. On the contrary, we did not observe any effect of the cGMP/PRKG1 (PKG) pathway modulators on the onset of hyperactivated sperm motility. Our results suggest that NO stimulates human sperm motility via the activation of sGC, the subsequent synthesis of cGMP, and the activation of cGMP-dependent protein kinases.


2001 ◽  
Vol 204 (7) ◽  
pp. 1319-1332 ◽  
Author(s):  
H. Aonuma ◽  
P.L. Newland

Little is known of the action of nitric oxide (NO) at the synaptic level on identified interneurones in local circuits that process mechanosensory signals. Here, we examine the action of NO in the terminal abdominal ganglion of the crayfish Pacifastacus leniusculus, where it has modulatory effects on the synaptic inputs of 17 identified ascending interneurones mediated by electrical stimulation of a sensory nerve. To analyse the role of NO in the processing of sensory signals, we bath-applied the NO donor SNAP, the NO scavenger PTIO, the nitric oxide synthase (NOS) inhibitor l-NAME, the NOS substrate l-arginine, a cyclic GMP (cGMP) analogue, 8-Br-cGMP, and the soluble guanylate cyclase (sGC) inhibitor ODQ. The effects of these chemicals on the synaptic inputs of the interneurones could be divided into two distinct classes. The NO donor SNAP enhanced the inputs to one class of interneurone (class 1) and depressed those to another (class 2). Neither the inactive isomer NAP nor degassed SNAP had any effect on the inputs to these same classes of interneurone. The NO scavenger PTIO caused the opposite effects to those of the NO donor SNAP, indicating that endogenous NO may have an action in local circuits. Preventing the synthesis of NO using l-NAME had the opposite effect to that of SNAP on each response class of interneurone. Increasing the synthesis of endogenous NO by applying l-arginine led to effects on both response classes of interneurone similar to those of SNAP. Taken together, these results suggested that NO was the active component in mediating the changes in amplitude of the excitatory postsynaptic potentials. Finally, the effects of 8-Br-cGMP were similar to those of the NO donor, indicating the possible involvement of a NO-sensitive guanylate cyclase. This was confirmed by preventing the synthesis of cGMP by sGC using ODQ, which caused the opposite effects to those of 8-Br-cGMP on the two response classes of interneurone. The results indicate that a NO-cGMP signal transduction pathway, in which NO regulates transmitter release from mechanosensory afferents onto intersegmental ascending interneurones, is probably present in the local circuits of the crayfish.


2003 ◽  
Vol 284 (5) ◽  
pp. C1215-C1222 ◽  
Author(s):  
Yukiko Kaneko ◽  
Tomohisa Ishikawa ◽  
Satoshi Amano ◽  
Koichi Nakayama

In isolated rat pancreatic β-cells, the nitric oxide (NO) donor NOC-7 at 1 μM reduced the amplitude of the oscillations of cytosolic Ca2+ concentration ([Ca2+]c) induced by 11.1 mM glucose, and at 10 μM terminated them. In the presence of N G-nitro-l-arginine (l-NNA), however, NOC-7 at 0.5 and 1 μM increased the amplitude of the [Ca2+]c oscillations, although the NO donor at 10 μM still suppressed them. Aqueous NO solution also had a dual effect on the [Ca2+]c oscillations. The soluble guanylate cyclase inhibitor LY-83583 and the cGMP-dependent protein kinase inhibitor KT5823 inhibited the stimulatory effect of NO, and 8-bromo-cGMP increased the amplitude of the [Ca2+]c oscillations. Patch-clamp analyses in the perforated configuration showed that 8-bromo-cGMP inhibited whole cell ATP-sensitive K+ currents in the isolated rat pancreatic β-cells, suggesting that the inhibition by cGMP of ATP-sensitive K+ channels is, at least in part, responsible for the stimulatory effect of NO on the [Ca2+]c oscillations. In the presence ofl-NNA, the glucose-induced insulin secretion from isolated islets was facilitated by 0.5 μM NOC-7, whereas it was suppressed by 10 μM NOC-7. These results suggest that NO facilitates glucose-induced [Ca2+]c oscillations of β-cells and insulin secretion at low concentrations, which effects are mediated by cGMP, whereas NO inhibits them in a cGMP-independent manner at high concentrations.


1995 ◽  
Vol 268 (5) ◽  
pp. G831-G842 ◽  
Author(s):  
F. S. Cayabyab ◽  
E. E. Daniel

The ionic mechanisms by which nitric oxide (NO) or a related compound mediates the inhibitory junction potentials (IJPs) of the opossum esophageal circular smooth muscle were studied using microelectrodes and double sucrose gap. The NO donors, 3-morpholino-sydnonimine hydrochloride and sodium nitroprusside, induced 15- to 20-mV hyperpolarizations that reversed near the potassium equilibrium potential as did the IJPs. They inhibited the IJPs and decreased electrotonic potentials (increased conductance) even during restoration of the resting membrane potential by application of depolarizing current. Quinine was more efficacious than apamin in inhibiting the IJPs or NO donor hyperpolarizations, whereas the other K+ channel blockers tested (tetraethylammonium, charybdotoxin, 4-aminopyridine, Cs+, and glibenclamide) were without effect. Glibenclamide abolished the hyperpolarizing effects of the K+ channel opener BRL-34915. Low Cl- Krebs (isethionate substitutions) caused hyperpolarizations, increased electrotonic potentials, and reduced IJPs. The neural blockers, tetrodotoxin, omega-conotoxin GVIA, and N omega-nitro-L-arginine methyl ester, inhibited IJPs but not the responses to NO donors, indicating a postjunctional effect. Methylene blue and cystamine, soluble guanylate cyclase inhibitors, suppressed IJPs and responses to NO donors. We conclude that NO mediates esophageal IJPs, which depend on guanosine 3',5'-cyclic monophosphate elevation and activation of quinine- and apamin-sensitive K+ channels.


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