scholarly journals Natriuretic Peptides and Nitric Oxide Stimulate cGMP Synthesis in Different Cellular Compartments

2006 ◽  
Vol 128 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Leslie A. Piggott ◽  
Kathryn A. Hassell ◽  
Zuzana Berkova ◽  
Andrew P. Morris ◽  
Michael Silberbach ◽  
...  

Cyclic nucleotide-gated (CNG) channels are a family of ion channels activated by the binding of cyclic nucleotides. Endogenous channels have been used to measure cyclic nucleotide signals in photoreceptor outer segments and olfactory cilia for decades. Here we have investigated the subcellular localization of cGMP signals by monitoring CNG channel activity in response to agonists that activate either particulate or soluble guanylyl cyclase. CNG channels were heterologously expressed in either human embryonic kidney (HEK)-293 cells that stably overexpress a particulate guanylyl cyclase (HEK-NPRA cells), or cultured vascular smooth muscle cells (VSMCs). Atrial natriuretic peptide (ANP) was used to activate the particulate guanylyl cyclase and the nitric oxide donor S-nitroso-n-acetylpenicillamine (SNAP) was used to activate the soluble guanylyl cyclase. CNG channel activity was monitored by measuring Ca2+ or Mn2+ influx through the channels using the fluorescent dye, fura-2. We found that in HEK-NPRA cells, ANP-induced increases in cGMP levels activated CNG channels in a dose-dependent manner (0.05–10 nM), whereas SNAP (0.01–100 μM) induced increases in cGMP levels triggered little or no activation of CNG channels (P < 0.01). After pretreatment with 100 μM 3-isobutyl-1-methylxanthine (IBMX), a nonspecific phosphodiesterase inhibitor, ANP-induced Mn2+ influx through CNG channels was significantly enhanced, while SNAP-induced Mn2+ influx remained small. In contrast, we found that in the presence of IBMX, both 1 nM ANP and 100 μM SNAP triggered similar increases in total cGMP levels. We next sought to determine if cGMP signals are compartmentalized in VSMCs, which endogenously express particulate and soluble guanylyl cyclase. We found that 10 nM ANP induced activation of CNG channels more readily than 100 μM SNAP; whereas 100 μM SNAP triggered higher levels of total cellular cGMP accumulation. These results suggest that cGMP signals are spatially segregated within cells, and that the functional compartmentalization of cGMP signals may underlie the unique actions of ANP and nitric oxide.

2005 ◽  
Vol 230 (4) ◽  
pp. 242-250 ◽  
Author(s):  
Jun Su ◽  
Peter M. Scholz ◽  
Harvey R. Weiss

Particulate guanylyl cyclase (pGC) and soluble guanylyl cyclase (sGC) are cGMP-generation systems distributed in different intracellular locations. Our aim was to test the hypothesis that the functional effects of cGMP produced by pGC and sGC on contraction and Ca2+ transients would differ in ventricular myocytes. We measured myocyte shortening from adult mice using a video edge-detector and investigated the functional changes after stimulating pGC with C-type natriuretic peptide (CNP; 10–8 M and 10–7 M) or sGC with S-nitroso-N-acetyl-penicillamine (SNAP; nitric oxide donor; 10–6 M and 10–5 M). Significant concentration-dependent decreases in percentage shortening (PCS), maximal rate of shortening (RSmax), and relaxation (RRmax) were produced by CNP. To a similar degree, SNAP concentration-dependently reduced PCS, RSmax, and RRmax. The addition of Rp-8-[(4-chlorophenyl)thio]-cGMPS triethylamine (cGMP-dependent protein kinase inhibitor; 5 × 10–6 M) or erythro-9-(2-hydroxy-3-nonyl) adenine (cGMP-stimulated cAMP phosphodiesterase inhibitor; 10–5 M) reduced the responses induced by CNP or SNAP, suggesting that their actions were through cGMP-mediated pathways. While SNAP significantly increased intracellular cGMP concentration by 57%, CNP had little effect on cGMP production. We also found that CNP markedly decreased the amplitude of Ca2+ transients while SNAP had little effect, suggesting the cGMP generated by sGC may decrease myofilament Ca2+ sensitivity. The small amount of cGMP generated by pGC had a major effect in reducing Ca2+ level. This study suggested the existence of compartmentalization for cGMP in ventricular myocytes.


2011 ◽  
Vol 301 (6) ◽  
pp. H2313-H2321 ◽  
Author(s):  
Calvin K. Y. Chan ◽  
Judith Mak ◽  
Yuansheung Gao ◽  
Ricky Y. K. Man ◽  
Paul M. Vanhoutte

The present study investigated the mechanism underlying the transient potentiation of vasoconstriction by hypoxia in isolated porcine coronary arteries. Isometric tension was measured in rings with or without endothelium. Hypoxia (Po2 <30 mmHg) caused a transient further increase in tension (hypoxic augmentation) in contracted (with U46619) preparations. The hypoxic response was endothelium dependent and abolished by inhibitors of nitric oxide synthase [ Nω-nitro-l-arginine methyl ester (l-NAME)] or soluble guanylyl cyclase (ODQ and NS2028). The addition of DETA NONOate (nitric oxide donor) in the presence of l-NAME restored the hypoxic augmentation, suggesting the involvement of the nitric oxide pathway. However, the same was not observed after incubation with 8-bromo-cyclic GMP, atrial natriuretic peptide, or isoproterenol. Assay of the cyclic GMP content showed no change upon exposure to hypoxia in preparations with and without endothelium. Incubation with protein kinase G and protein kinase A inhibitors did not inhibit the hypoxic augmentation. Thus the hypoxic augmentation is dependent on nitric oxide and soluble guanylyl cyclase but independent of cyclic GMP. The hypoxic augmentation persisted in calcium-free buffer and in the presence of nifedipine, ruling out a role for extracellular calcium influx. Hypoxia did not alter the intracellular calcium concentration, as measured by confocal fluorescence microscopy. This observation and the findings that hypoxic augmentation is enhanced by thapsigargin (sarco/endoplasmic reticulum calcium ATPase inhibitor) and inhibited by HA1077 or Y27632 (Rho kinase inhibitors) demonstrate the involvement of calcium sensitization in the phenomenon.


2000 ◽  
Vol 279 (6) ◽  
pp. C1938-C1945 ◽  
Author(s):  
M. Nara ◽  
P. D. K. Dhulipala ◽  
G. J. Ji ◽  
U. R. Kamasani ◽  
Y.-X. Wang ◽  
...  

We coexpressed the human large-conductance, calcium-activated K (KCa) channel (α- and β-subunits) and rat atrial natriuretic peptide (ANP) receptor genes in Xenopus oocytes to examine the mechanism of guanylyl cyclase stimulatory coupling to the channel. Exposure of oocytes to ANP stimulated whole cell KCa currents by 21 ± 3% (at 60 mV), without altering current kinetics. Similarly, spermine NONOate, a nitric oxide donor, increased KCa currents (20 ± 4% at 60 mV) in oocytes expressing the channel subunits alone. Stimulation of KCacurrents by ANP was inhibited in a concentration-dependent manner by a peptide inhibitor of cGMP-dependent protein kinase (PKG). Receptor/channel stimulatory coupling was not completely abolished by mutating the cAMP-dependent protein kinase phosphorylation site on the α-subunit (S869; Nars M, Dhulipals PD, Wang YX, and Kotlikoff MI. J Biol Chem 273: 14920–14924, 1998) or by mutating a neighboring consensus PKG site (S855), but mutation of both residues virtually abolished coupling. Spermine NONOate also failed to stimulate channels expressed from the double mutant cRNAs. These data indicate that nitric oxide donors stimulate KCa channels through cGMP-dependent phosphorylation and that two serine residues (855 and 869) underlie this stimulatory coupling.


Zygote ◽  
2006 ◽  
Vol 14 (1) ◽  
pp. 9-16 ◽  
Author(s):  
J. Petr ◽  
R. Rajmon ◽  
E. Chmelíková ◽  
M. Tománek ◽  
V. Lánská ◽  
...  

Pig oocytes matured in vitro were parthenogenetically activated (78%) after treatment with 2 mM nitric oxide-donor (±)-S-nitroso-N-acetylpenicillamine (SNAP) for 24 h. Inhibition of soluble guanylyl cyclase with the specific inhibitors 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) or 6-anilino-5,8-quinolinequinone (LY83583) suppressed the SNAP-induced activation in a dose-dependent manner (23% of activated oocytes after treatment with 400 μM ODQ; 12% of activated oocytes after treatment with 40 μM LY83583). 8-Bromo-cyclic guanosine monophosphate (8-Br-cGMP), a phosphodiesterase-resistant analogue of cGMP, enhances the effect of suboptimal doses (0.1 or 0.5 mM) of the NO donor SNAP. DT3, a specific inhibitor of cGMP-dependent protein kinase (PKG, PKG), is also able to inhibit the activation of pig oocytes after NO donor treatment. Involvement of the cGMP-dependent signalling pathway is specific for NO-induced oocyte activation, because both the guanylyl cyclase inhibitor ODQ and the PKG inhibitor DT3 are unable to inhibit activation in oocytes treated with the calcium ionophore A23187. These data indicate that the activation of pig oocytes with an NO donor is cGMP-dependent and that PKG plays an important role in this mode of oocyte activation.


2007 ◽  
Vol 293 (5) ◽  
pp. H3080-H3087 ◽  
Author(s):  
Tian Xia ◽  
Christiana Dimitropoulou ◽  
Jingmin Zeng ◽  
Galina N. Antonova ◽  
Connie Snead ◽  
...  

The nitric oxide receptor soluble guanylyl cyclase (sGC) exists in multimeric protein complexes, including heat shock protein (HSP) 90 and endothelial nitric oxide synthase. Inhibition of HSP90 by geldanamycin causes proteasomal degradation of sGC protein. In this study, we have investigated whether COOH terminus of heat shock protein 70-interacting protein (CHIP), a co-chaperone molecule that is involved in protein folding but is also a chaperone-dependent ubiquitin E3 ligase, could play a role in the process of degradation of sGC. Transient overexpression of CHIP in COS-7 cells degraded heterologous sGC in a concentration-related manner; this downregulation of sGC was abrogated by the proteasome inhibitor MG-132. Transfection of tetratricopeptide repeats and U-box domain CHIP mutants attenuated sGC degradation, suggesting that both domains are indispensable for CHIP function. Results from immunoprecipitation and indirect immunofluorescent microscopy experiments demonstrated that CHIP is associated with sGC, HSP90, and HSP70 in COS-7 cells. Furthermore, CHIP increased the association of HSP70 with sGC. In in vitro ubiquitination assays using purified proteins and ubiquitin enzymes, E3 ligase CHIP directly ubiquitinated sGC; this ubiquitination was potentiated by geldanamycin in COS-7 cells, followed by proteasomal degradation. In rat aortic smooth muscle cells, endogenous sGC was also degraded by adenovirus-infected wild-type CHIP but not by the chaperone interaction-deficient K30A CHIP, whereas CHIP, but not K30A, attenuated sGC expression in, and nitric oxide donor-induced relaxation of, rat aortic rings, suggesting that CHIP plays a regulatory role under physiological conditions. This study reveals a new mechanism for the regulation of sGC, an important mediator of cellular and vascular function.


2001 ◽  
Vol 155 (2) ◽  
pp. 271-278 ◽  
Author(s):  
Florian Mullershausen ◽  
Michael Russwurm ◽  
W. Joseph Thompson ◽  
Li Liu ◽  
Doris Koesling ◽  
...  

Most of the effects of the signaling molecule nitric oxide (NO) are mediated by cGMP, which is synthesized by soluble guanylyl cyclase and degraded by phosphodiesterases. Here we show that in platelets and aortic tissue, NO led to a biphasic response characterized by a tremendous increase in cGMP (up to 100-fold) in less than 30 s and a rapid decline, reflecting the tightly controlled balance of guanylyl cyclase and phosphodiesterase activities. Inverse to the reported increase in sensitivity caused by NO shortage, concentrating NO attenuated the cGMP response in a concentration-dependent manner. We found that guanylyl cyclase remained fully activated during the entire course of the cGMP response; thus, desensitization was not due to a switched off guanylyl cyclase. However, when intact platelets were incubated with NO and then lysed, enhanced activity of phosphodiesterase type 5 was detected in the cytosol. Furthermore, this increase in cGMP degradation is paralleled by the phosphorylation of phosphodiesterase type 5 at Ser-92. Thus, our data suggest that NO-induced desensitization of the cGMP response is caused by the phosphorylation and subsequent activity increase of phosphodiesterase type 5.


Author(s):  
Thomas J Pirtle ◽  
Richard A Satterlie

Abstract Typically, the marine mollusk, Clione limacina, exhibits a slow, hovering locomotor gait to maintain its position in the water column. However, the animal exhibits behaviorally relevant locomotor swim acceleration during escape response and feeding behavior. Both nitric oxide and serotonin mediate this behavioral swim acceleration. In this study, we examine the role that the second messenger, cGMP, plays in mediating nitric oxide and serotonin-induced swim acceleration. We observed that the application of an analog of cGMP or an activator of soluble guanylyl cyclase increased fictive locomotor speed recorded from Pd-7 interneurons of the animal’s locomotor central pattern generator. Moreover, inhibition of soluble guanylyl cyclase decreased fictive locomotor speed. These results suggest that basal levels of cGMP are important for slow swimming and that increased production of cGMP mediates swim acceleration in Clione. Because nitric oxide has its effect through cGMP signaling and because we show herein that cGMP produces cellular changes in Clione swim interneurons that are consistent with cellular changes produced by serotonin application, we hypothesize that both nitric oxide and serotonin function via a common signal transduction pathway that involves cGMP. Our results show that cGMP mediates nitric oxide-induced but not serotonin-induced swim acceleration in Clione.


2001 ◽  
Vol 276 (33) ◽  
pp. 30737-30743 ◽  
Author(s):  
Markus Koglin ◽  
Kai Vehse ◽  
Lars Budaeus ◽  
Hasso Scholz ◽  
Sönke Behrends

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