scholarly journals Low guanylyl cyclase activity in Weddell seals: implications for peripheral vasoconstriction and perfusion of the brain during diving

2019 ◽  
Vol 316 (6) ◽  
pp. R704-R715 ◽  
Author(s):  
Allyson G. Hindle ◽  
Kaitlin N. Allen ◽  
Annabelle J. Batten ◽  
Luis A. Hückstädt ◽  
Jason Turner-Maier ◽  
...  
Keyword(s):  
Guanylyl Cyclase ◽  
Soluble Guanylyl Cyclase ◽  
Amino Acid Sequences ◽  
No Production ◽  
Diving Response ◽  
No Donor ◽  
Weddell Seals ◽  
Terrestrial Mammals ◽  
And Function ◽  
The Brain

Nitric oxide (NO) is a potent vasodilator, which improves perfusion and oxygen delivery during tissue hypoxia in terrestrial animals. The vertebrate dive response involves vasoconstriction in select tissues, which persists despite profound hypoxia. Using tissues collected from Weddell seals at necropsy, we investigated whether vasoconstriction is aided by downregulation of local hypoxia signaling mechanisms. We focused on NO–soluble guanylyl cyclase (GC)-cGMP signaling, a well-known vasodilatory transduction pathway. Seals have a lower GC protein abundance, activity, and capacity to respond to NO stimulation than do terrestrial mammals. In seal lung homogenates, GC produced less cGMP (20.1 ± 3.7 pmol·mg protein−1·min−1) than the lungs of dogs (−80 ± 144 pmol·mg protein−1·min−1 less than seals), sheep (−472 ± 96), rats (−664 ± 104) or mice (−1,160 ± 104, P < 0.0001). Amino acid sequences of the GC enzyme α-subunits differed between seals and terrestrial mammals, potentially affecting their structure and function. Vasoconstriction in diving Weddell seals is not consistent across tissues; perfusion is maintained in the brain and heart but decreased in other organs such as the kidney. A NO donor increased median GC activity 49.5-fold in the seal brain but only 27.4-fold in the kidney, consistent with the priority of cerebral perfusion during diving. Nos3 expression was high in the seal brain, which could improve NO production and vasodilatory potential. Conversely, Pde5a expression was high in the seal renal artery, which may increase cGMP breakdown and vasoconstriction in the kidney. Taken together, the results of this study suggest that alterations in the NO-cGMP pathway facilitate the diving response.

Maturational changes in the regulation of pulmonary vascular tone by nitric oxide in neonatal rats

2007 ◽  
Vol 293 (5) ◽  
pp. L1261-L1270 ◽  
Author(s):  
Louis G. Chicoine ◽  
Michael L. Paffett ◽  
Mark R. Girton ◽  
Matthew J. Metropoulus ◽  
Mandar S. Joshi ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Guanylyl Cyclase ◽  
Vascular Tone ◽  
Age Groups ◽  
Soluble Guanylyl Cyclase ◽  
No Production ◽  
Sprague Dawley ◽  
No Donor ◽  
Early Postnatal Development ◽  
Old Rats

Nitric oxide (NO) is an important regulator of vasomotor tone in the pulmonary circulation. We tested the hypothesis that the role NO plays in regulating vascular tone changes during early postnatal development. Isolated, perfused lungs from 7- and 14-day-old Sprague-Dawley rats were studied. Baseline total pulmonary vascular resistance (PVR) was not different between age groups. The addition of KCl to the perfusate caused a concentration-dependent increase in PVR that did not differ between age groups. However, the nitric oxide synthase (NOS) inhibitor Nω-nitro-l-arginine augmented the K+-induced increase in PVR in both groups, and the effect was greater in lungs from 14-day-old rats vs. 7-day-old rats. Lung levels of total endothelial, inducible, and neuronal NOS proteins were not different between groups; however, the production rate of exhaled NO was greater in lungs from 14-day-old rats compared with those of 7-day-old rats. Vasodilation to 0.1 μM of the NO donor spermine NONOate was greater in 14-day lungs than in 7-day lungs, and lung levels of both soluble guanylyl cyclase and cGMP were greater at 14 days than at 7 days. Vasodilation to 100 μM of the cGMP analog 8-(4-chlorophenylthio)guanosine-3′,5′-cyclic monophosphate was greater in 7-day lungs than in 14-day lungs. Our results demonstrate that the pulmonary vascular bed depends more on NO production to modulate vascular tone at 14 days than at 7 days of age. The observed differences in NO sensitivity may be due to maturational increases in soluble guanylyl cyclase protein levels.

scholarly journals Cellular Distribution and Function of Soluble Guanylyl Cyclase in Rat Kidney and Liver

2001 ◽  
Vol 12 (11) ◽  
pp. 2209-2220 ◽  
Author(s):  
FRANZISKA THEILIG ◽  
MAGDALENA BOSTANJOGLO ◽  
HERMANN PAVENSTÄDT ◽  
CLEMENS GRUPP ◽  
GUDRUN HOLLAND ◽  
...  
Keyword(s):  
Guanylyl Cyclase ◽  
Mesangial Cells ◽  
Rat Kidney ◽  
Soluble Guanylyl Cyclase ◽  
No Donor ◽  
Ito Cells ◽  
Reverse Transcription Pcr ◽  
Cgmp Signaling ◽  
And Function

Abstract. Soluble guanylyl cyclase (sGC) catalyzes the biosynthesis of cGMP in response to binding of L-arginine-derived nitric oxide (NO). Functionally, the NO-sGC-cGMP signaling pathway in kidney and liver has been associated with regional hemodynamics and the regulation of glomerular parameters. The distribution of the ubiquitous sGC isoform α1β1 sGC was studied with a novel, highly specific antibody against the β1 subunit. In parallel, the presence of mRNA encoding both subunits was investigated by using in situ hybridization and reverse transcription-PCR assays. The NO-induced, sGC-dependent accumulation of cGMP in cytosolic extracts of tissues and cells was measured in vitro. Renal glomerular arterioles, including the renin-producing granular cells, mesangium, and descending vasa recta, as well as cortical and medullary interstitial fibroblasts, expressed sGC. Stimulation of isolated mesangial cells, renal fibroblasts, and hepatic Ito cells with a NO donor resulted in markedly increased cytosolic cGMP levels. This assessment of sGC expression and activity in vascular and interstitial cells of kidney and liver may have implications for understanding the role of local cGMP signaling cascades.

Phosphodiesterase-5 inhibitors oppose hyperoxic vasoconstriction and accelerate seizure development in rats exposed to hyperbaric oxygen

2009 ◽  
Vol 106 (4) ◽  
pp. 1234-1242 ◽  
Author(s):  
Ivan T. Demchenko ◽  
Alex Ruehle ◽  
Barry W. Allen ◽  
Richard D. Vann ◽  
Claude A. Piantadosi
Keyword(s):  
Hyperbaric Oxygen ◽  
Positive Function ◽  
Initial Response ◽  
Brain Regions ◽  
No Production ◽  
No Donor ◽  
Mean Values ◽  
Brain Nitric Oxide ◽  
The Brain ◽  
Phosphodiesterase 5

Oxygen is a potent cerebral vasoconstrictor, but excessive exposure to hyperbaric oxygen (HBO2) can reverse this vasoconstriction by stimulating brain nitric oxide (NO) production, which increases cerebral blood flow (CBF)—a predictor of O2 convulsions. We tested the hypothesis that phosphodiesterase (PDE)-5 blockers, specifically sildenafil and tadalafil, increase CBF in HBO2 and accelerate seizure development. To estimate changes in cerebrovascular responses to hyperoxia, CBF was measured by hydrogen clearance in anesthetized rats, either control animals or those pretreated with one of these blockers, with the NO inhibitor Nω-nitro-l-arginine methyl ester (l-NAME), with the NO donor S-nitroso- N-acetylpenicillamine (SNAP), or with a blocker combined with l-NAME. Animals were exposed to 30% O2 at 1 atm absolute (ATA) (“air”) or to 100% O2 at 4 or 6 ATA. EEG spikes indicated central nervous system CNS O2 toxicity. The effects of PDE-5 blockade varied as a positive function of ambient Po2. In air, CBF did not increase significantly, except after pretreatment with SNAP. However, at 6 ATA O2, mean values for CBF increased and values for seizure latency decreased, both significantly; pretreatment with l-NAME abolished these effects. Conscious rats treated with sildenafil before HBO2 were also more susceptible to CNS O2 toxicity, as demonstrated by significantly shortened convulsive latency. Decreases in regional CBF reflect net vasoconstriction in the brain regions studied, since mean arterial pressures remained constant or increased throughout. Thus PDE-5 blockers oppose the protective vasoconstriction that is the initial response to hyperbaric hyperoxia, decreasing the safety of HBO2 by hastening onset of CNS O2 toxicity.

scholarly journals cGMP: a unique 2nd messenger molecule – recent developments in cGMP research and development

2019 ◽  
Vol 393 (2) ◽  
pp. 287-302 ◽  
Author(s):  
Andreas Friebe ◽  
Peter Sandner ◽  
Achim Schmidtko
Keyword(s):  
Guanylyl Cyclase ◽  
Soluble Guanylyl Cyclase ◽  
Cell Types ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Therapeutic Implications ◽  
Cellular Effects ◽  
Recent Developments ◽  
And Function ◽  
Messenger Molecule

AbstractCyclic guanosine monophosphate (cGMP) is a unique second messenger molecule formed in different cell types and tissues. cGMP targets a variety of downstream effector molecules and, thus, elicits a very broad variety of cellular effects. Its production is triggered by stimulation of either soluble guanylyl cyclase (sGC) or particulate guanylyl cyclase (pGC); both enzymes exist in different isoforms. cGMP-induced effects are regulated by endogenous receptor ligands such as nitric oxide (NO) and natriuretic peptides (NPs). Depending on the distribution of sGC and pGC and the formation of ligands, this pathway regulates not only the cardiovascular system but also the kidney, lung, liver, and brain function; in addition, the cGMP pathway is involved in the pathogenesis of fibrosis, inflammation, or neurodegeneration and may also play a role in infectious diseases such as malaria. Moreover, new pharmacological approaches are being developed which target sGC- and pGC-dependent pathways for the treatment of various diseases. Therefore, it is of key interest to understand this pathway from scratch, beginning with the molecular basis of cGMP generation, the structure and function of both guanylyl cyclases and cGMP downstream targets; research efforts also focus on the subsequent signaling cascades, their potential crosstalk, and also the translational and, ultimately, the clinical implications of cGMP modulation. This review tries to summarize the contributions to the “9th International cGMP Conference on cGMP Generators, Effectors and Therapeutic Implications” held in Mainz in 2019. Presented data will be discussed and extended also in light of recent landmark findings and ongoing activities in the field of preclinical and clinical cGMP research.

TNF-alpha and IFN-gamma induce expression of nitric oxide synthase in cultured rat medullary interstitial cells

1995 ◽  
Vol 269 (2) ◽  
pp. F212-F217 ◽  
Author(s):  
K. S. Lau ◽  
O. Nakashima ◽  
G. R. Aalund ◽  
L. Hogarth ◽  
K. Ujiie ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Nitric Oxide Synthase ◽  
Vascular Smooth Muscle ◽  
Guanylyl Cyclase ◽  
Soluble Guanylyl Cyclase ◽  
Tnf Alpha ◽  
No Production ◽  
Ifn Gamma ◽  
Oxide Synthase

Cytokines increase the expression of the inducible (type II) nitric oxide synthase (NOS) in macrophages, liver, and renal epithelial cells. Previously, we found that cultured rat medullary interstitial cells (RMIC) contain high levels of soluble guanylyl cyclase. To determine whether these cells can also produce NO, we studied the effects of tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) on NO production, NOS II mRNA, and NOS II protein expression. Both TNF-alpha and IFN-gamma, in the presence of a low concentration of the other cytokine, caused dose-dependent increases in NO production. Exposure to TNF-alpha and IFN-gamma stimulated the production of NOS II mRNA, as determined by Northern blotting. Restriction mapping of reverse transcription-polymerase chain reaction products indicated that normal cells contained macrophage NOS II, whereas cytokine-stimulated cells contained primarily vascular smooth muscle NOS II and some macrophage NOS II. The appearance of NOS II protein was demonstrated by Western blotting. RMIC cell guanosine 3',5'-cyclic monophosphate accumulation increased 129-fold in response to the cytokines. NOS inhibitors decreased nitrite production. We conclude that 1) TNF-alpha and IFN-gamma induce the expression of vascular smooth muscle NOS II and production of NO in RMIC, and 2) NO acts as an autocrine activator of the soluble guanylyl cyclase in RMIC.

Biphasic Roles for the Soluble Guanylyl Cyclase (sGC) In Platelet Activation In Mice

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 486-486
Author(s):  
Guoying Zhang ◽  
Binggang Xiang ◽  
Radek C. Skoda ◽  
Susan S. Smyth ◽  
Xiaoping Du ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Guanylyl Cyclase ◽  
Conflicts Of Interest ◽  
Soluble Guanylyl Cyclase ◽  
Wild Type ◽  
No Donor ◽  
Cgmp Production ◽  
Deficient Mice

Abstract Abstract 486 The role of intracellular secondary messenger cGMP in platelet activation has been controversial, with both stimulatory and inhibitory roles reported. The platelet cGMP is believed to be predominantly synthesized by soluble guanylyl cyclase (sGC), which is activated by nitric oxide (NO). To specifically determine the role of sGC-dependent cGMP synthesis in platelet function and in vivo thrombosis and hemostasis, we produced mice harboring a “floxed” sGC beta1 allele. In the “floxed” sGC beta1 mice (sGC beta1fl/fl), the exons 7 and 8 of sGC beta1 gene and an inserted Neo cassette were flanked with three LoxP sites. Platelet-specific deletion of sGC beta1fl/fl allele was accomplished through breeding of the sGC beta1fl/fl mice with pf4-Cre recombinase transgenic mice. Immunoblotting showed the complete absence of this protein in sGC beta1fl/fl/Cre platelets. Mice lacking sGC beta1 in platelets appeared to develop normally and had normal blood counts, including platelets. Blood pressure of platelet-specific sGC deficient mice was comparable to that of wild-type littermates. Inactivating the sGC beta1 gene in platelets abolished cGMP production induced by either NO donors or platelet agonists that are known to activate endogenous NO synthesis, confirming that both the platelet agonist-induced and NO donor-induced platelet cGMP production are predominantly mediated by sGC. Platelets lacking sGC exhibit a marked defect in aggregation and secretion in response to low doses of platelet agonists, collagen and thrombin. Importantly, tail-bleeding times were significantly prolonged in the platelet-specific sGC deficient mice compared with the wild-type littermates. In a FeCl3-induced carotid artery thrombosis model, time to occlusive thrombosis was prolonged in the platelet-specific sGC deficient mice, compared to wild type littermates. Thus, the agonist-stimulated sGC activation is important in promoting platelet granule secretion and aggregation. On the other hand, NO donor SNP-induced inhibition of platelet activation was abolished in sGC-deficient platelets. However, at high concentrations (>100μM), SNP inhibited platelet activation in both wild type and sGC deficient mice, indicating that both cGMP-dependent and -independent mechanisms are involved in NO donor-induced inhibition of platelet activation. Together, our data demonstrate that sGC contributes to both agonist-induced platelet activation and NO donor-induced platelet inhibition. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Nitric Oxide (NO) Donor Sodium Nitroprusside (SNP) and Its Potential for the Schizophrenia Therapy: Lights and Shadows

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3196
Author(s):  
Elli Zoupa ◽  
Nikolaos Pitsikas
Keyword(s):  
Nitric Oxide ◽  
Sodium Nitroprusside ◽  
Cognitive Deficits ◽  
Negative Symptoms ◽  
Mental Disease ◽  
No Production ◽  
No Donor ◽  
No Donors ◽  
Worldwide Population ◽  
The Brain

Schizophrenia is a severe psychiatric disorder affecting up to 1% of the worldwide population. Available therapy presents different limits comprising lack of efficiency in attenuating negative symptoms and cognitive deficits, typical features of schizophrenia and severe side effects. There is pressing requirement, therefore, to develop novel neuroleptics with higher efficacy and safety. Nitric oxide (NO), an intra- and inter-cellular messenger in the brain, appears to be implicated in the pathogenesis of schizophrenia. In particular, underproduction of this gaseous molecule is associated to this mental disease. The latter suggests that increment of nitrergic activity might be of utility for the medication of schizophrenia. Based on the above, molecules able to enhance NO production, as are NO donors, might represent a class of compounds candidates. Sodium nitroprusside (SNP) is a NO donor and is proposed as a promising novel compound for the treatment of schizophrenia. In the present review, we intended to critically assess advances in research of SNP for the therapy of schizophrenia and discuss its potential superiority over currently used neuroleptics.

scholarly journals Nitric Oxide Promotes Human Hematopoietic Stem Cell Homing and Engraftment Via cGMP-Pkg Signaling

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 807-807 ◽  
Author(s):  
Xinxin Huang ◽  
Bin Guo ◽  
Maegan L. Capitano ◽  
Hal E. Broxmeyer
Keyword(s):  
Guanylyl Cyclase ◽  
Pde5 Inhibitor ◽  
Soluble Guanylyl Cyclase ◽  
Treated Group ◽  
Vehicle Control ◽  
No Donor ◽  
Hematopoietic Stem ◽  
Cell Homing ◽  
Cd34 Cells ◽  
Hsc Transplantation

Abstract The success of hematopoietic stem cell (HSC) transplantation relies on adequate homing and long-term engraftment of HSC into the bone marrow (BM). The free radical nitric oxide (NO) is a gaseous molecule that plays important roles in a variety of physiological regulations. NO can freely diffuse across cellular membranes and activate an enzyme, soluble guanylyl cyclase, to produce cyclic guanosine monophosphate (cGMP) from guanosine triphosphate (GTP). cGMP binding activates cGMP-dependent protein kinase (PKG) and other proteins to regulate many biological processes. However, the roles of NO and cGMP in regulating HSC function still remain poorly understood. To explore the importance of NO signaling in HSC, we first evaluated the effects of NO on human cord blood (CB) HSC chemotaxis in an in vitro transwell migration assay. We found that treatment of human CB CD34+ cells for 16 hours with an NO synthesis inhibitor, L-NAME, did not affect chemotaxis towards CXCL12. However, treatment of human CB CD34+ cells 16 hours with NO donor compound sodium nitroprusside (SNP) resulted in 55% more migration toward CXCL12 compared to vehicle control. Enhanced chemotaxis by SNP was also observed in a more primitive HSC cell population (Lin-CD34+CD38-CD45RA-CD49f+CD90+, 71% more migration) suggesting NO donor treatment promote HSC migration. The other two NO donors, SNAP and NOC5 showed similar effects on promoting CD34+ cells and HSC migration. NO activates soluble guanylyl cyclase in target cells, so next we explored the relationship between HSC migration and soluble guanylyl cyclase. By treating human CB CD34+ cells with riociguat, a soluble guanylyl cyclase stimulator, we found that riociguat treatment also resulted in 78% more HSC migration toward CXCL12. The other soluble guanylyl cyclase activator BAY412272 showed a similar effect as riociguat by promoting HSC chemotaxis (68% more migration compared with vehicle control). Inside the cell cGMP is degraded by phosphodiesterase 5 (PDE5), so a PDE5 inhibitor would suppress cGMP breakdown and activate cGMP signaling. Consistently, we found that CD34+ cells with PDE5 inhibitor avanafil or sildenafil treatment showed increased HSC chemotaxis compared with vehicle control (57% and 62% more migration respectively). Next we used PKG inhibitor KT5823 to test whether PKG is involved in HSC migration and found that KT5823 totally blocked the effects of SNP, riociguat and avanafil on enhanced HSC migration, suggesting that NO promote HSC migration through cGMP-PKG signaling. To directly evaluate in vivo homing, vehicle, SNP or riociguat treated CB CD34+ cells were injected into sublethally irradiated NSG (NOD.Cg-PrkdcscidIL2rgtm1Wjl/Sz) mice, and human cell homing to mouse BM, as indicated by human CD45 percentage, was analyzed 24 hours after transplantation. Consistently, SNP or riociguat treatment resulted in a 2.1 fold and 2.3 fold increase of human cell homing in NSG mice respectively compared with vehicle control treatment. Next, we performed a limiting dilution assay to compare the frequency of SCID-repopulating cells (SRCs) in vehicle and riociguat treated CB CD34+ cells. Engraftment of riociguat-treated CB CD34+ cells was significantly increased in primary NSG recipient mice compared with that of vehicle control treated group four months after transplantation (47.6% vs 23.7%). Both human myeloid and lymphoid chimerisms were also increased. Poisson distribution analysis revealed an SRC frequency of 1/2977 in vehicle control treated group and 1/512 in Riociguat treatment, resulting in the presence of 335.9 SRCs and 1953.1 SRCs in 1×106 cells from vehicle control and riociguat-treated cultures. We are currently performing RNA-seq and quantitative proteomic analysis in riociguat-treated CB CD34+ cells to reveal specific downstream targets in regulating HSC homing. Taken together, our study suggests that human HSC homing and engraftment can be enhanced by modulating the NO/cGMP signaling pathway. Some compounds tested in our study, such as SNP, riociguat, avanafil are FDA approved medications broadly used for myocardial infarction, pulmonary hypertension and erectile dysfunction. So utilization of these drugs in HSC transplantation should be practical. Our work offers a new and simple approach to bolster the effectiveness of HSC transplantation. Disclosures No relevant conflicts of interest to declare.

scholarly journals Age Impairs Soluble Guanylyl Cyclase Function in Mouse Mesenteric Arteries

2021 ◽  
Vol 22 (21) ◽  
pp. 11412
Author(s):  
Cheng Zhong ◽  
Minze Xu ◽  
Sengül Boral ◽  
Holger Summer ◽  
Falk-Bach Lichtenberger ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Mrna Expression ◽  
Guanylyl Cyclase ◽  
Pde5 Inhibitor ◽  
Soluble Guanylyl Cyclase ◽  
Mesenteric Arteries ◽  
No Donor ◽  
Diabetic Vasculopathy ◽  
Endothelial Nitric Oxide

Endothelial dysfunction (ED) comes with age, even without overt vessel damage such as that which occurs in atherosclerosis and diabetic vasculopathy. We hypothesized that aging would affect the downstream signalling of the endothelial nitric oxide (NO) system in the vascular smooth muscle (VSM). With this in mind, resistance mesenteric arteries were isolated from 13-week (juvenile) and 40-week-old (aged) mice and tested under isometric conditions using wire myography. Acetylcholine (ACh)-induced relaxation was reduced in aged as compared to juvenile vessels. Pretreatment with L-NAME, which inhibits nitrix oxide synthases (NOS), decreased ACh-mediated vasorelaxation, whereby differences in vasorelaxation between groups disappeared. Endothelium-independent vasorelaxation by the NO donor sodium nitroprusside (SNP) was similar in both groups; however, SNP bolus application (10−6 mol L−1) as well as soluble guanylyl cyclase (sGC) activation by runcaciguat (10−6 mol L−1) caused faster responses in juvenile vessels. This was accompanied by higher cGMP concentrations and a stronger response to the PDE5 inhibitor sildenafil in juvenile vessels. Mesenteric arteries and aortas did not reveal apparent histological differences between groups (van Gieson staining). The mRNA expression of the α1 and α2 subunits of sGC was lower in aged animals, as was PDE5 mRNA expression. In conclusion, vasorelaxation is compromised at an early age in mice even in the absence of histopathological alterations. Vascular smooth muscle sGC is a key element in aged vessel dysfunction.

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