101
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Duong TTH, Antao S, Ellis NA, Myers SJ, Witting PK. Supplementation with a synthetic polyphenol limits oxidative stress and enhances neuronal cell viability in response to hypoxia-re-oxygenation injury. Brain Res 2008; 1219:8-18. [PMID: 18538307 DOI: 10.1016/j.brainres.2008.04.044] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 03/28/2008] [Accepted: 04/09/2008] [Indexed: 12/31/2022]
Abstract
Oxidative stress is associated with the pathology of acute and chronic neurodegenerative disease. Cultured human neuronal cells exposed to experimental hypoxia-re-oxygenation (H/R) injury responded with an increased production of reactive oxygen species (ROS) and a significant decrease in intracellular ATP. Expression of genes encoding for hypoxia-inducible factor 1-alpha (HIF1-alpha), inducible haemoxygenase-1 (HO-1), glucose transporter-1 (Glut-1), the oxygen-sensor neuroglobin (Nb) and Cu,Zn-superoxide dismutase (SOD1), catalase (CAT) and glutathione peroxidase-1 (Gpx-1) increased significantly in response to the insult. Enhanced expression of HO-1, SOD1 and CAT correlated with an increase in the corresponding protein activity. Despite the cellular response to bolster antioxidant capacity, apoptosis and necrosis increased following H/R injury. In contrast, ROS accumulation, the endogenous gene response and cell death was limited in neuronal cells pre-incubated with 50 or 100, but not 10 microM of the phenolic antioxidant 3,3',5,5'-tetra-t-butyl-biphenyl-4,4'-diol (BP) prior to H/R injury. These data indicate that the early endogenous gene response to H/R injury is unable to inhibit neuronal dysfunction and that increasing cellular antioxidant capacity with a synthetic polyphenol (>10 microM) is potentially neuro-protective.
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Affiliation(s)
- T T Hong Duong
- Vascular Biology Group, ANZAC Research Institute, Concord Hospital, Concord, NSW 2139, Australia
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102
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Abstract
This review is intended to stimulate interest in the effect of increased expression of heme oxygenase-1 (HO-1) protein and increased levels of HO activity on normal and pathological states. The HO system includes the heme catabolic pathway, comprising HO and biliverdin reductase, and the products of heme degradation, carbon monoxide (CO), iron, and biliverdin/bilirubin. The role of the HO system in diabetes, inflammation, heart disease, hypertension, neurological disorders, transplantation, endotoxemia and other pathologies is a burgeoning area of research. This review focuses on the clinical potential of increased levels of HO-1 protein and HO activity to ameliorate tissue injury. The use of pharmacological and genetic probes to manipulate HO, leading to new insights into the complex relationship of the HO system with biological and pathological phenomena under investigation, is reviewed. This information is critical in both drug development and the implementation of clinical approaches to moderate and to alleviate the numerous chronic disorders in humans affected by perturbations in the HO system.
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Affiliation(s)
- Nader G Abraham
- New York Medical College, Basic Science Building, Valhalla, NY 10595, USA.
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103
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Derbyshire ER, Gunn A, Ibrahim M, Spiro TG, Britt RD, Marletta MA. Characterization of two different five-coordinate soluble guanylate cyclase ferrous-nitrosyl complexes. Biochemistry 2008; 47:3892-9. [PMID: 18302323 DOI: 10.1021/bi7022943] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Soluble guanylate cyclase (sGC), a hemoprotein, is the primary nitric oxide (NO) receptor in higher eukaryotes. The binding of NO to sGC leads to the formation of a five-coordinate ferrous-nitrosyl complex and a several hundred-fold increase in cGMP synthesis. NO activation of sGC is influenced by GTP and the allosteric activators YC-1 and BAY 41-2272. Electron paramagnetic resonance (EPR) spectroscopy shows that the spectrum of the sGC ferrous-nitrosyl complex shifts in the presence of YC-1, BAY 41-2272, or GTP in the presence of excess NO relative to the heme. These molecules shift the EPR signal from one characterized by g 1 = 2.083, g 2 = 2.036, and g 3 = 2.012 to a signal characterized by g 1 = 2.106, g 2 = 2.029, and g 3 = 2.010. The truncated heme domain constructs beta1(1-194) and beta2(1-217) were compared to the full-length enzyme. The EPR spectrum of the beta2(1-217)-NO complex is characterized by g 1 = 2.106, g 2 = 2.025, and g 3 = 2.010, indicating the protein is a good model for the sGC-NO complex in the presence of the activators, while the spectrum of the beta1(1-194)-NO complex resembles the EPR spectrum of sGC in the absence of the activators. Low-temperature resonance Raman spectra of the beta1(1-194)-NO and beta2(1-217)-NO complexes show that the Fe-NO stretching vibration of the beta2(1-217)-NO complex (535 cm (-1)) is significantly different from that of the beta1(1-194)-NO complex (527 cm (-1)). This shows that sGC can adopt different five-coordinate ferrous nitrosyl conformations and suggests that the Fe-NO conformation characterized by this unique EPR signal and Fe-NO stretching vibration represents a highly active sGC state.
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Affiliation(s)
- Emily R Derbyshire
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3320, USA
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104
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Bauer M, Huse K, Settmacher U, Claus RA. The heme oxygenase – carbon monoxide system: regulation and role in stress response and organ failure. Intensive Care Med 2008; 34:640-8. [DOI: 10.1007/s00134-008-1010-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Accepted: 11/05/2007] [Indexed: 11/30/2022]
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105
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Abdel Aziz MT, El-Asmar MF, Mostafa T, Atta H, Fouad HH, Roshdy NK, Rashed LA, Obaia EA, Sabry DA, Abdel Aziz AT, Drummond G, Olszanecki R. Effect of hemin and carbon monoxide releasing molecule (CORM-3) on cGMP in rat penile tissue. J Sex Med 2007; 5:336-43. [PMID: 18179459 DOI: 10.1111/j.1743-6109.2007.00695.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Cyclic guanosine monophosphate (cGMP) levels can be regulated by heme oxygenase-1 and 2 (HO-1 and HO-2)-derived carbon monoxide (CO). AIMS Assessment of the effect of upregulating CO in rat corpora cavernosa (CC) on cavernous cGMP. METHODS Three experimental groups were studied: first group (N = 40), short-term HO induction over 2 weeks by injection of intraperitoneal increasing doses of hemin; the second group (N = 40) was subjected to intracavernosal injection of CO donor, CORM-3, or its inactive form (iCORM-3) over 2 weeks; the third group (N = 60) was subdivided into three subgroups: the first one received a combined hemin and CORM-3, the second one received hemin and its inhibitor stannus mesoporphyrin (SnMP), and third one received a combined hemin, CORM-3, and SnMP. MAIN OUTCOME MEASURES In CC, HO-1 and HO-2 gene expression, Northern blot and Western blot, cGMP levels, and HO enzyme activity. RESULTS In the first group, maximum induction of HO-1 gene expression, HO enzyme activity, and cGMP occurred with 4-mg hemin dose with a successive increase over 2 weeks. In the second group, CORM-3 increased cGMP by twofold compared with iCORM-3, and also increased HO-1 protein. In the third group, SnMP inhibited the enhancing effect of CORM-3 and HO on erectile signaling molecules; i.e., HO-1 gene, enzyme activity, and cGMP. CONCLUSIONS CORM-3- or hemin-mediated CO release could increase cavernous tissue cGMP.
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Affiliation(s)
- M Talaat Abdel Aziz
- Molecular Biology Unit, Medical Biochemistry Department, Faculty of Medicine, Cairo University, Cairo, Egypt
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106
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YC-1 attenuates homotypic human neutrophil aggregation through inhibition of phosphodiesterase activity. Eur J Pharmacol 2007; 579:395-402. [PMID: 18001706 DOI: 10.1016/j.ejphar.2007.10.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 10/04/2007] [Accepted: 10/16/2007] [Indexed: 11/22/2022]
Abstract
This study was undertaken to assess the effects of 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1), a known activator of soluble guanylyl cyclase, on formyl-l-methionyl-l-leucyl-l-phenylalanine (FMLP) and complement component 5a (C5a)-induced homotypic human neutrophil aggregation. YC-1 as well as the phosphodiesterase (PDE)4 inhibitors rolipram and Ro 20-1724, but not the PDE3 inhibitor milrinone, inhibited the aggregation responses stimulated by FMLP and C5a. In contrast, sodium nitroprusside (SNP) had no effect on FMLP- or C5a-induced neutrophil aggregation. Moreover, SNP together with YC-1 failed to modify the YC-1-induced responses. In addition, YC-1 and rolipram, but not milrinone, induced substantial increases in cAMP levels, which occurred through the inhibition of PDE activity but not an increase in adenylate cyclase function. Interestingly, adenosine deaminase abolished the inhibitory effects and cAMP levels of YC-1, rolipram, and Ro 20-1724. In conclusion, these results indicate that the inhibitory effect of YC-1 on homotypic neutrophil aggregation is attributed to an elevation in the cAMP concentration through inhibition of the activity of PDE, which may potentiate the autocrine functions of endogenous adenosine.
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107
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Derbyshire ER, Marletta MA. Butyl isocyanide as a probe of the activation mechanism of soluble guanylate cyclase. Investigating the role of non-heme nitric oxide. J Biol Chem 2007; 282:35741-8. [PMID: 17916555 DOI: 10.1074/jbc.m705557200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nitric oxide (NO) is a physiologically relevant activator of the hemoprotein soluble guanylate cyclase (sGC). In the presence of NO, sGC is activated several hundredfold above the basal level by a mechanism that remains to be elucidated. The heme ligand n-butyl isocyanide (BIC) was used to probe the mechanism of NO activation of sGC. Electronic absorption spectroscopy was used to show that BIC binds to the sGC heme, forming a 6-coordinate complex with an absorbance maximum at 429 nm. BIC activates sGC 2-5-fold, and synergizes with the allosteric activator YC-1, to activate the enzyme 15-25-fold. YC-1 activates the sGC-BIC complex, and leads to an increase in both the V(max) and K(m). BIC was also used to probe the mechanism of NO activation. The activity of the sGC-BIC complex increases 15-fold in the presence of NO, without displacing BIC at the heme, which is consistent with previous reports that proposed the involvement of a non-heme NO binding site in the activation process.
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Affiliation(s)
- Emily R Derbyshire
- Department of Molecular, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
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108
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Dong DL, Zhang Y, Lin DH, Chen J, Patschan S, Goligorsky MS, Nasjletti A, Yang BF, Wang WH. Carbon monoxide stimulates the Ca2(+)-activated big conductance k channels in cultured human endothelial cells. Hypertension 2007; 50:643-51. [PMID: 17724275 DOI: 10.1161/hypertensionaha.107.096057] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We used the whole-cell patch-clamp technique to study K channels in the human umbilical vein endothelial cells and identified a 201 pS K channel, which was blocked by tetraethylammonium and iberiotoxin but not by TRAM34 and apamin. This suggests that the Ca(2+)-activated big-conductance K channel (BK) is expressed in endothelial cells. Application of carbon monoxide (CO) or tricarbonylchloro(glycinato)ruthenium(II), a water soluble CO donor, stimulated the BK channels. Moreover, application of hemin, a substrate of heme oxygenase, mimicked the effect of CO and increased the BK channel activity. The stimulatory effect of hemin was significantly diminished by tin mesoporphyrin, an inhibitor of heme oxygenase. To determine whether the stimulatory effect of CO on the BK channel was mediated by NO and the cGMP-dependent pathway, we examined the effect of CO on BK channels in cells treated with, N(G)-nitro-l-arginine methyl ester, 1H(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one, an inhibitor of soluble guanylate cyclase, or KT5823, an inhibitor of protein kinase G. Addition of either diethylamine NONOate or sodium nitroprusside significantly increased BK channel activity. Inhibition of endogenous NO synthesis with N(G)-nitro-l-arginine methyl ester, blocking soluble guanylate cyclase or protein kinase G, delayed but did not prevent the CO-induced activation of BK channels. Finally, application of an antioxidant agent, ebselen, had no effect on CO-mediated stimulation of BK channels in human umbilical vein endothelial cells. We conclude that BK channels are expressed in human umbilical vein endothelial cells and that they are activated by both CO and NO. CO activates BK channels directly, as well as via a mechanism involving NO or the cGMP-dependent pathway.
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Affiliation(s)
- De-Li Dong
- Department of Pharmacology, Harbin Medical University, Harbin, China
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109
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Alexander PG, Chau L, Tuan RS. Role of nitric oxide in chick embryonic organogenesis and dysmorphogenesis. ACTA ACUST UNITED AC 2007; 79:581-94. [PMID: 17676596 DOI: 10.1002/bdra.20386] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Nitric oxide (NO), produced by the nitric oxide synthase family of enzymes, mediates multiple signaling functions, and when unchecked, NO causes pathological damage. Exposure of embryos to a variety of teratogens, including carbon monoxide (CO), has been shown to increase reactive intermediates, such as NO, and recent work showed that either the excess or absence of NO caused morphological defects. While endogenous NO is known to regulate many adult tissues, its role during embryonic organogenesis and/or in mediating responses to teratogen exposure has not been explored. METHODS We have examined here the presence of NO during normal chick embryonic organogenesis, and investigated the teratogenicity of NO through the application of sodium nitroprusside (SNP), which mimics NO overproduction, and NG-monomethyl-L-arginine (L-NMMA), which inhibits endogenous NOS activity. RESULTS Topical treatment with SNP or L-NMMA for 18 h resulted in morphological defects, specifically in the neural tube and somites, which corresponded to sites of altered apoptosis. The location of NO was histochemically correlated with the observed morphological defects. Coadministration of SNP or L-NMMA with CO showed functional coregulation and interaction between NO and CO in chick embryonic development. CONCLUSIONS Our results showed that regulation of NO is essential for normal axial development, that sites of altered NO expression correlate to those of altered apoptosis and dysmorphogenesis, and that CO coadministration resulted in a rectification of normal NO expression. Collectively, these results suggest that alteration in endogenous NO/CO signaling is responsible, at least in part, for the observed NO-induced teratogenesis.
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Affiliation(s)
- Peter G Alexander
- Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892-8022, USA
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110
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Nickels TJ, Reed GW, Drummond JT, Blevins DE, Lutz MC, Wilson DF. Does nitric oxide modulate transmitter release at the mammalian neuromuscular junction? Clin Exp Pharmacol Physiol 2007; 34:318-26. [PMID: 17324144 DOI: 10.1111/j.1440-1681.2007.04562.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Application of the nitric oxide (NO) donor, sodium nitrite and the NO synthase substrate l-arginine had no effect on nerve-evoked transmitter release in the rat isolated phrenic nerve/hemidiaphragm preparation; however, when adenosine A(1) receptors were blocked with the adenosine A(1) receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) prior to application of sodium nitrate or l-arginine, a significant increase in transmitter release was observed. In addition, the NO donor s-nitroso-N-acetylpenicillamine (SNAP) significantly increased transmitter release in the presence of DPCPX. In the present study, we have made the assumption that these NO donors elevate the level of NO in the tissue. Future studies should test other NO-donating compounds and also monitor the NO concentrations in the tissue to ensure that these effects are, in fact, NO induced. 2. Elevation of cGMP in this preparation with the guanylyl cyclase activator 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) significantly enhanced transmitter release. In the presence of DPCPX and the selective guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), which blocks the production of cGMP, the excitatory effects of sodium nitrite and l-arginine were abolished. 3. These results suggest that NO serves to enhance transmitter release at the rat neuromuscular junction (NMJ) via a cGMP pathway and this facilitation of transmitter release can be blocked with adenosine. Previously, we demonstrated that adenosine inhibits N-type calcium channels. Because NO only affects transmitter release when adenosine A(1) receptors are blocked, we suggest that NO enhances transmitter release by enhancing calcium influx via N-type calcium channels. Further studies are needed to confirm that NO alters transmitter release via cGMP and that this action involves the N-type calcium channel. 4. The results of the present study are consistent with a model of NO neuromodulation that has been proposed for the mammalian vagal-atrial junction. This model suggests that NO acts on NO-sensitive guanylyl cyclase to increase the intracellular levels of cGMP. In turn, cGMP inhibits phosphodiesterase-3, increasing levels of cAMP, which then acts on the N-type calcium channels to enhance calcium influx, leading to an increase in transmitter release. Our only modification to this model for the NMJ is that adenosine serves to block the modulation of transmitter release by NO.
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Affiliation(s)
- Travis J Nickels
- Center for Neuroscience, Department of Zoology, Miami University, Oxford, OH 45056, USA
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111
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Martin NI, Derbyshire ER, Marletta MA. Synthesis and evaluation of a phosphonate analogue of the soluble guanylate cyclase activator YC-1. Bioorg Med Chem Lett 2007; 17:4938-41. [PMID: 17587571 DOI: 10.1016/j.bmcl.2007.06.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 06/06/2007] [Accepted: 06/07/2007] [Indexed: 11/22/2022]
Abstract
Soluble guanylate cyclase (sGC) is activated by the known benzylindazole derivative YC-1 [1-benzyl-3-(5'-hydroxymethyl-2'-furyl)-indazole]. YC-1 also acts synergistically with CO, activating sGC to a level comparable to that achieved upon binding of nitric oxide, the endogenous activator of sGC. We here describe the synthesis of a YC-1 phosphonate analogue with improved aqueous solubility as well as its effects on sGC.
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Affiliation(s)
- Nathaniel I Martin
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
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112
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Chou LC, Huang LJ, Yang JS, Lee FY, Teng CM, Kuo SC. Synthesis of furopyrazole analogs of 1-benzyl-3-(5-hydroxymethyl-2-furyl)indazole (YC-1) as novel anti-leukemia agents. Bioorg Med Chem 2007; 15:1732-40. [PMID: 17189698 DOI: 10.1016/j.bmc.2006.12.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 12/01/2006] [Accepted: 12/02/2006] [Indexed: 11/30/2022]
Abstract
As part of our continuing search for potential anticancer drug candidates in YC-1 analogs, several 1-benzyl-3-(substituted aryl)-5-methylfuro[3,2-c]pyrazoles were synthesized and evaluated for their cytotoxicity against HL-60 cell line. Among these compounds, 1-benzyl-3-(5-hydroxymethyl-2-furyl)-5-methylfuro[3,2-c]pyrazole (1) showed more potency than YC-1. Through investigation of action mechanism, it was found that compound 1 induced terminal differentiation of HL-60 cells toward granulocyte lineage and promoted HL-60 cell differentiation by regulation of Bcl-2 and c-Myc proteins. Meanwhile, compound 1 also demonstrated apoptosis inducing effect. Such anti-leukemia mechanism of action is apparently different from that of YC-1 which mainly works by inducing apoptosis, but not cell differentiation. Therefore, compound 1 is identified here as a new lead compound of cell differentiating agent and apoptosis inducer for further development of new anti-leukemia agents.
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Affiliation(s)
- Li-Chen Chou
- Graduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung, Taiwan
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113
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Winger JA, Derbyshire ER, Marletta MA. Dissociation of nitric oxide from soluble guanylate cyclase and heme-nitric oxide/oxygen binding domain constructs. J Biol Chem 2006; 282:897-907. [PMID: 17098738 DOI: 10.1074/jbc.m606327200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulation of soluble guanylate cyclase (sGC), the primary NO receptor, is linked to NO binding to the prosthetic heme group. Recent studies have demonstrated that the degree and duration of sGC activation depend on the presence and ratio of purine nucleotides and on the presence of excess NO. We measured NO dissociation from full-length alpha1beta1 sGC, and the constructs beta1(1-194), beta1(1-385), and beta2(1-217), at 37 and 10 degrees C with and without the substrate analogue guanosine-5'-[(alpha,beta-methylene]triphosphate (GMPCPP) or the activator 3-(5'-hydroxymethyl-3'-furyl)-1-benzylindazole (YC-1). NO dissociation from each construct was complex, requiring two exponentials to fit the data. Decreasing the temperature decreased the contribution of the faster exponential for all constructs. Inclusion of YC-1 moderately accelerated NO dissociation from sGC and beta2(1-217) at 37 degrees C and dramatically accelerated NO dissociation from sGC at 10 degrees C. The presence of GMPCPP also dramatically accelerated NO dissociation from sGC at 10 degrees C. This acceleration is due to increases in the observed rate for each exponential and in the contribution of the faster exponential. Increases in the contribution of the faster exponential correlated with higher activation of sGC by NO. These data indicate that the sGC ferrous-nitrosyl complex adopts two 5-coordinate conformations, a lower activity "closed" form, which releases NO slowly, and a higher activity "open" form, which releases NO rapidly. The ratio of these two species affects the overall rate of NO dissociation. These results have implications for the function of sGC in vivo, where there is evidence for two NO-regulated activity states.
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Affiliation(s)
- Jonathan A Winger
- Department of Medicinal Chemistry, the University of Michigan, Ann Arbor, Michigan 48109, USA
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114
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Evgenov OV, Pacher P, Schmidt PM, Haskó G, Schmidt HHHW, Stasch JP. NO-independent stimulators and activators of soluble guanylate cyclase: discovery and therapeutic potential. Nat Rev Drug Discov 2006; 5:755-68. [PMID: 16955067 PMCID: PMC2225477 DOI: 10.1038/nrd2038] [Citation(s) in RCA: 533] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Soluble guanylate cyclase (sGC) is a key signal-transduction enzyme activated by nitric oxide (NO). Impaired bioavailability and/or responsiveness to endogenous NO has been implicated in the pathogenesis of cardiovascular and other diseases. Current therapies that involve the use of organic nitrates and other NO donors have limitations, including non-specific interactions of NO with various biomolecules, lack of response and the development of tolerance following prolonged administration. Compounds that activate sGC in an NO-independent manner might therefore provide considerable therapeutic advantages. Here we review the discovery, biochemistry, pharmacology and clinical potential of haem-dependent sGC stimulators (including YC-1, BAY 41-2272, BAY 41-8543, CFM-1571 and A-350619) and haem-independent sGC activators (including BAY 58-2667 and HMR-1766).
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Affiliation(s)
- Oleg V Evgenov
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, CLN 309, Boston, Massachusetts 02114, USA
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115
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Martin E, Berka V, Bogatenkova E, Murad F, Tsai AL. Ligand Selectivity of Soluble Guanylyl Cyclase. J Biol Chem 2006; 281:27836-45. [PMID: 16864588 DOI: 10.1074/jbc.m601078200] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although soluble guanylyl cyclase (sGC) functions in an environment in which O(2), NO, and CO are potential ligands for its heme moiety, the enzyme displays a high affinity for only its physiological ligand, NO, but has a limited affinity for CO and no affinity for O(2). Recent studies of a truncated version of the sGC beta(1)-subunit containing the heme-binding domain (Boon, E. M., Huang, S H., and Marletta, M. A. (2005) Nat. Chem. Biol., 1, 53-59) showed that introduction of the hydrogen-bonding tyrosine into the distal heme pocket changes the ligand specificity of the heme moiety and results in an oxygen-binding sGC. The hypothesis that the absence of hydrogen-bonding residues in the distal heme pocket is sufficient to provide oxygen discrimination by sGC was put forward. We tested this hypothesis in a context of a complete sGC heterodimer containing both the intact alpha(1)- and beta(1)-subunits. We found that the I145Y substitution in the full-length beta-subunit of the sGC heterodimer did not produce an oxygen-binding enzyme. However, this substitution impeded the association of NO and destabilized the NO.heme complex. The tyrosine in the distal heme pocket also impeded both the binding and dissociation of the CO ligand. We propose that the mechanism of oxygen exclusion by sGC not only involves the lack of hydrogen bonding in the distal heme pocket, but also depends on structural elements from other domains of sGC.
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Affiliation(s)
- Emil Martin
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, USA.
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116
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Bermúdez-Ocaña DY, Ambriz-Tututi M, Pérez-Severiano F, Granados-Soto V. Pharmacological evidence for the participation of NO-cyclic GMP-PKG-K+ channel pathway in the antiallodynic action of resveratrol. Pharmacol Biochem Behav 2006; 84:535-42. [PMID: 16899286 DOI: 10.1016/j.pbb.2006.06.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Revised: 05/23/2006] [Accepted: 06/30/2006] [Indexed: 11/15/2022]
Abstract
The possible participation of the nitric oxide (NO)-cyclic GMP-protein kinase G (PKG)-K+ channels pathway in the antiallodynic action of resveratrol and YC-1 in spinal nerve injured rats was assessed. Ligation of L5/L6 spinal nerves produced a clear-cut tactile allodynia in the rats. Intrathecal administration of resveratrol (100-600 microg) and 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (0.1-2.7 microg, YC-1, a soluble guanylyl cyclase activator) decreased tactile allodynia induced by ligation of L5/L6 spinal nerves. Intrathecal treatment with NG-L-nitro-arginine methyl ester (10-100 microg, L-NAME, a NO synthase inhibitor), 1H-(1,2,4)-oxadiazolo(4,2-a)quinoxalin-1-one (1-10 microg, ODQ, a soluble guanylyl cyclase inhibitor), KT-5823 (5-500 ng, a PKG inhibitor) and iberiotoxin (5-500 ng, a large-conductance Ca2+ -activated K+ channel blocker), but not NG-D-nitro-arginine methyl ester (100 microg, D-NAME, an inactive isomer of L-NAME), glibenclamide (12.5-50 microg, ATP-sensitive K+ channel blocker) or vehicle, significantly diminished resveratrol (300 microg)- and YC-1 (2.7 microg)-induced spinal antiallodynia. These effects were independent of prostaglandin synthesis inhibition as indomethacin did not affect resveratrol-induced antiallodynia. Results suggest that resveratrol and YC-1 could activate the proteins of the NO-cyclic GMP-PKG spinal pathway or large-conductance Ca2+ -activated, but not ATP-sensitive, K+ channels at the spinal cord in order to produce at least part of their antiallodynic effect in this model of neuropathy.
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Affiliation(s)
- Deysi Y Bermúdez-Ocaña
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados, Sede Sur, México, D.F., Mexico
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117
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González-Luis G, Cogolludo A, Moreno L, Lodi F, Tamargo J, Pérez-Vizcaíno F, Villamor E. Relaxant Effects of the Soluble Guanylate Cyclase Activator and NO Sensitizer YC-1 in Piglet Pulmonary Arteries. Neonatology 2006; 90:66-72. [PMID: 16534188 DOI: 10.1159/000091968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Accepted: 10/11/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND The indazole derivative YC-1 has been characterized as a nitric oxide (NO)-independent and heme dependent soluble guanylate cyclase (sGC) activator, which also sensitizes sGC to NO. OBJECTIVE To examine the effects of YC-1 on vascular relaxation in newborn and 2-week-old piglet pulmonary arteries. The effect of YC-1 on the relaxation induced by exogenous NO was also analyzed. METHODS Isolated rings from third branch pulmonary arteries and fifth-seventh-generation intrapulmonary arterioles were mounted in organ chambers for isometric tension recording. Arteries were precontracted with the thromboxane A2 mimetic U46619. RESULTS YC-1 induced relaxation was greater in 2-week-old pulmonary arteries and was abolished by the sGC inhibitor ODQ (10 microM). YC-1 induced relaxation was similar in conduit pulmonary arteries and arterioles. In the 2-week-old conduit pulmonary arteries, the response to YC-1 was significantly reduced when the endothelium was removed or after incubation with the NO synthase inhibitor L-NAME (0.1 mM). YC-1 augmented NO-induced relaxation in 2-week-old but not in neonatal conduit pulmonary arteries. CONCLUSIONS Our results indicate that YC-1 induced pulmonary vascular relaxation in conduit and resistance pulmonary arteries and these effects increased with postnatal age. In the 2-week-old conduit pulmonary arteries and besides being a direct activator of sGC, YC-1 produced endothelium-dependent relaxation and synergized with exogenous NO.
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Affiliation(s)
- Gema González-Luis
- Department of Pediatrics, University Hospital Maastricht, Research Institute Growth and Development, Maastricht, The Netherlands
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118
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Rothkegel C, Schmidt PM, Stoll F, Schröder H, Schmidt HHHW, Stasch JP. Identification of residues crucially involved in soluble guanylate cyclase activation. FEBS Lett 2006; 580:4205-13. [PMID: 16831427 DOI: 10.1016/j.febslet.2006.06.079] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 06/23/2006] [Accepted: 06/27/2006] [Indexed: 11/21/2022]
Abstract
The ubiquitous heterodimeric nitric oxide (NO) receptor soluble guanylate cyclase (sGC) plays a key role in various signal transduction pathways. Binding of NO takes place at the prosthetic heme moiety at the N-terminus of the beta(1)-subunit of sGC. The induced structural changes lead to an activation of the catalytic C-terminal domain of the enzyme and to an increased conversion of GTP into the second messenger cyclic GMP (cGMP). In the present work we selected and substituted different residues of the sGC heme-binding pocket based on a sGC homology model. The generated sGC variants were tested in a cGMP reporter cell for their effect on the enzyme activation by heme-dependent (NO, BAY 41-2272) stimulators and heme-independent (BAY 58-2667) activators. The use of these experimental tools allows the enzyme's heme content to be explored in a non-invasive manner. Asp(44), Asp(45) and Phe(74) of the beta(1)-subunit were identified as being crucially important for functional enzyme activation. beta(1)Asp(45) may serve as a switch between different conformational states of sGC and point to a possible mechanism of action of the heme dependent sGC stimulator BAY 41-2272. Furthermore, our data shows that the activation profile of beta(1)IIe(145) Tyr is unchanged compared to the native enzyme, suggesting that Tyr(145) does not confer the ability to distinguish between NO and O(2). In summary, the present work further elucidated intramolecular mechanisms underlying the NO- and BAY 41-2272-mediated sGC activation and raises questions regarding the postulated role of Tyr(145) for ligand discrimination.
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Affiliation(s)
- Christiane Rothkegel
- Cardiovascular Research, Bayer HealthCare, Aprather Weg 18a, D-42096 Wuppertal, Germany
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119
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Yazawa S, Tsuchiya H, Hori H, Makino R. Functional characterization of two nucleotide-binding sites in soluble guanylate cyclase. J Biol Chem 2006; 281:21763-21770. [PMID: 16754683 DOI: 10.1074/jbc.m508983200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Soluble guanylate cyclase is a heterodimeric hemoprotein composed of alpha- and beta-subunits with a homologous motif to the nucleotide-binding sites of adenylate cyclases. Homology modeling of guanylate cyclase, based on the crystal structure of adenylate cyclase, reveals a single GTP-binding site and a putative second site pseudosymmetric to the GTP-binding site. However, the role of this pseudosymmetric site has remained unclear. Using equilibrium dialysis, we identified two nucleotide-binding sites with high and low affinity for alpha,beta-methylene guanosine 5'-triphosphate (GMP-CPP). In contrast, 2'-dADP occupied both sites with equivalent affinities. Adenosine-5'-beta,gamma-imido triphosphate (AMP-PNP), which competitively inhibited the cyclase reaction, bound solely to the high affinity site, indicating the role of this site as the catalytic site. The function of the low affinity site was examined using allosteric activators YC-1 and BAY 41-2272. YC-1 significantly reduced the affinity of 2'-dADP, probably by competing for the same site as 2'-dADP. BAY 41-2272 totally inhibited the specific binding of one molecule of 2'-dADP as well as GMP-CPP. This suggests that the activators compete with these nucleotides for the low affinity site. Infrared and EPR analyses of the enzymic CO- and NO-hemes also supported the suggested role of the low affinity site as a target for the activators. Our results imply that the low affinity site is the pseudosymmetric site, which binds YC-1 or BAY 41-2272.
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Affiliation(s)
- Shinsuke Yazawa
- Department of Life Science, College of Science, Rikkyo University, Nishi-ikebukuro 3-34-1, Toshima-ku, Tokyo 171-8501
| | - Hidemi Tsuchiya
- Department of Life Science, College of Science, Rikkyo University, Nishi-ikebukuro 3-34-1, Toshima-ku, Tokyo 171-8501
| | - Hiroshi Hori
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Ryu Makino
- Department of Life Science, College of Science, Rikkyo University, Nishi-ikebukuro 3-34-1, Toshima-ku, Tokyo 171-8501.
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120
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Boon EM, Davis JH, Tran R, Karow DS, Huang SH, Pan D, Miazgowicz MM, Mathies RA, Marletta MA. Nitric oxide binding to prokaryotic homologs of the soluble guanylate cyclase beta1 H-NOX domain. J Biol Chem 2006; 281:21892-21902. [PMID: 16728401 DOI: 10.1074/jbc.m600557200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The heme cofactor in soluble guanylate cyclase (sGC) is a selective receptor for NO, an important signaling molecule in eukaryotes. The sGC heme domain has been localized to the N-terminal 194 amino acids of the beta1 subunit of sGC and is a member of a family of conserved hemoproteins, called the H-NOX family (Heme-Nitric Oxide and/or OXygen-binding domain). Three new members of this family have now been cloned and characterized, two proteins from Legionella pneumophila (L1 H-NOX and L2 H-NOX) and one from Nostoc punctiforme (Np H-NOX). Like sGC, L1 H-NOX forms a 5-coordinate Fe(II)-NO complex. However, both L2 H-NOX and Np H-NOX form temperature-dependent mixtures of 5- and 6-coordinate Fe(II)-NO complexes; at low temperature, they are primarily 6-coordinate, and at high temperature, the equilibrium is shifted toward a 5-coordinate geometry. This equilibrium is fully reversible with temperature in the absence of free NO. This process is analyzed in terms of a thermally labile proximal Fe(II)-His bond and suggests that in both the 5- and 6-coordinate Fe(II)-NO complexes of L2 H-NOX and Np H-NOX, NO is bound in the distal heme pocket of the H-NOX fold. NO dissociation kinetics for L1 H-NOX and L2 H-NOX have been determined and support a model in which NO dissociates from the distal side of the heme in both 5- and 6-coordinate complexes.
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Affiliation(s)
- Elizabeth M Boon
- Department of Chemistry, University of California, Berkeley, California 94720
| | - Joseph H Davis
- Department of Chemistry, University of California, Berkeley, California 94720
| | - Rosalie Tran
- Department of Chemistry, University of California, Berkeley, California 94720
| | - David S Karow
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Shirley H Huang
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
| | - Duohai Pan
- Department of Chemistry, University of California, Berkeley, California 94720
| | | | - Richard A Mathies
- Department of Chemistry, University of California, Berkeley, California 94720; Division of Physical Biosciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Michael A Marletta
- Department of Chemistry, University of California, Berkeley, California 94720; Department of Molecular and Cell Biology, University of California, Berkeley, California 94720; Division of Physical Biosciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720.
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121
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Ryter SW, Alam J, Choi AMK. Heme oxygenase-1/carbon monoxide: from basic science to therapeutic applications. Physiol Rev 2006; 86:583-650. [PMID: 16601269 DOI: 10.1152/physrev.00011.2005] [Citation(s) in RCA: 1732] [Impact Index Per Article: 96.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The heme oxygenases, which consist of constitutive and inducible isozymes (HO-1, HO-2), catalyze the rate-limiting step in the metabolic conversion of heme to the bile pigments (i.e., biliverdin and bilirubin) and thus constitute a major intracellular source of iron and carbon monoxide (CO). In recent years, endogenously produced CO has been shown to possess intriguing signaling properties affecting numerous critical cellular functions including but not limited to inflammation, cellular proliferation, and apoptotic cell death. The era of gaseous molecules in biomedical research and human diseases initiated with the discovery that the endothelial cell-derived relaxing factor was identical to the gaseous molecule nitric oxide (NO). The discovery that endogenously produced gaseous molecules such as NO and now CO can impart potent physiological and biological effector functions truly represented a paradigm shift and unraveled new avenues of intense investigations. This review covers the molecular and biochemical characterization of HOs, with a discussion on the mechanisms of signal transduction and gene regulation that mediate the induction of HO-1 by environmental stress. Furthermore, the current understanding of the functional significance of HO shall be discussed from the perspective of each of the metabolic by-products, with a special emphasis on CO. Finally, this presentation aspires to lay a foundation for potential future clinical applications of these systems.
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Affiliation(s)
- Stefan W Ryter
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
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122
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Leffler CW, Parfenova H, Jaggar JH, Wang R. Carbon monoxide and hydrogen sulfide: gaseous messengers in cerebrovascular circulation. J Appl Physiol (1985) 2006; 100:1065-76. [PMID: 16467393 PMCID: PMC1363746 DOI: 10.1152/japplphysiol.00793.2005] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
This review focuses on two gaseous cellular messenger molecules, CO and H2S, that are involved in cerebrovascular flow regulation. CO is a dilatory mediator in active hyperemia, autoregulation, hypoxic dilation, and counteracting vasoconstriction. It is produced from heme by a constitutively expressed enzyme [heme oxygenase (HO)-2] expressed highly in the brain and by an inducible enzyme (HO-1). CO production is regulated by controlling substrate availability, HO-2 catalytic activity, and HO-1 expression. CO dilates arterioles by binding to heme that is bound to large-conductance Ca2+-activated K+ channels. This binding elevates channel Ca2+ sensitivity, that increases coupling of Ca2+ sparks to large-conductance Ca2+-activated K+ channel openings and, thereby, hyperpolarizes the vascular smooth muscle. In addition to dilating blood vessels, CO can either inhibit or accentuate vascular cell proliferation and apoptosis, depending on conditions. H2S may also function as a cerebrovascular dilator. It is produced in vascular smooth muscle cells by hydrolysis of l-cysteine catalyzed by cystathione gamma-lyase (CSE). H2S dilates arterioles at physiologically relevant concentrations via activation of ATP-sensitive K+ channels. In addition to dilating blood vessels, H2S promotes apoptosis of vascular smooth muscle cells and inhibits proliferation-associated vascular remodeling. Thus both CO and H2S modulate the function and the structure of circulatory system. Both the HO-CO and CSE-H2S systems have potential to interact with NO and prostanoids in the cerebral circulation. Much of the physiology and biochemistry of HO-CO and CSE-H2S in the cerebral circulation remains open for exploration.
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Affiliation(s)
- Charles W Leffler
- Dept. of Physiology, University of Tennessee Health Science Center, 894 Union Ave., Memphis, TN 38163, USA.
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123
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Alexander SPH, Mathie A, Peters JA. Soluble guanylyl cyclase (E.C. 4.6.1.2). Br J Pharmacol 2006. [DOI: 10.1038/sj.bjp.0706589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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124
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Puranik M, Weeks CL, Lahaye D, Kabil Ö, Taoka S, Nielsen SB, Groves JT, Banerjee R, Spiro TG. Dynamics of carbon monoxide binding to cystathionine beta-synthase. J Biol Chem 2006; 281:13433-13438. [PMID: 16505479 PMCID: PMC2745537 DOI: 10.1074/jbc.m600246200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cystathionine beta-synthase (CBS) condenses homocysteine, a toxic metabolite, with serine in a pyridoxal phosphate-dependent reaction. It also contains a heme cofactor to which carbon monoxide (CO) or nitric oxide can bind, resulting in enzyme inhibition. To understand the mechanism of this regulation, we have investigated the equilibria and kinetics of CO binding to the highly active catalytic core of CBS, which is dimeric. CBS exhibits strong anticooperativity in CO binding with successive association constants of 0.24 and 0.02 microm(-1). Stopped flow measurements reveal slow CO association (0.0166 s(-1)) limited by dissociation of the endogenous ligand, Cys-52. Rebinding of CO and of Cys-52 following CO photodissociation were independently monitored via time-resolved resonance Raman spectroscopy. The Cys-52 rebinding rate, 4000 s(-1), is essentially unchanged between pH 7.6 and 10.5, indicating that the pK(a) of Cys-52 is shifted below pH 7.6. This effect is attributed to the nearby Arg-266 residue, which is proposed to form a salt bridge with the dissociated Cys-52, thereby inhibiting its protonation and slowing rebinding to the Fe. This salt bridge suggests a pathway for enzyme inactivation upon CO binding, because Arg-266 is located on a helix that connects the heme and pyridoxal phosphate cofactor domains.
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Affiliation(s)
- Mrinalini Puranik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| | - Colin L Weeks
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| | - Dorothee Lahaye
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| | - Ömer Kabil
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664
| | - Shinichi Taoka
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664
| | | | - John T Groves
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| | - Ruma Banerjee
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664.
| | - Thomas G Spiro
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544.
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125
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Hering KW, Artz JD, Pearson WH, Marletta MA. The design and synthesis of YC-1 analogues as probes for soluble guanylate cyclase. Bioorg Med Chem Lett 2006; 16:618-21. [PMID: 16326101 DOI: 10.1016/j.bmcl.2005.10.093] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Revised: 10/14/2005] [Accepted: 10/14/2005] [Indexed: 10/25/2022]
Abstract
Soluble guanylate cyclase (sGC) is highly activated in the presence of both YC-1 (1-benzyl-3-(5'-hydroxymethyl-2'-furyl)-indazole) and CO. In this report, the design, synthesis, and activity (i.e., sGC activation) of photolabile analogues of 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1) are presented. Initial results with 6-azido-3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole led to the synthesis of a tritium-labeled analogue. When photoactivated, this analogue labeled the alpha-subunit of sGC.
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Affiliation(s)
- Kirk W Hering
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
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126
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Gorren ACF, Russwurm M, Kollau A, Koesling D, Schmidt K, Mayer B. Effects of nitroglycerin/L-cysteine on soluble guanylate cyclase: evidence for an activation/inactivation equilibrium controlled by nitric oxide binding and haem oxidation. Biochem J 2006; 390:625-31. [PMID: 15907191 PMCID: PMC1198942 DOI: 10.1042/bj20050565] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
GTN (nitroglycerin; glycerol trinitrate) causes dilation of blood vessels via activation of nitric oxide (NO)-sensitive sGC (soluble guanylate cyclase), a heterodimeric haem protein that catalyses the conversion of GTP into cGMP. Activation of sGC by GTN requires enzymatic or non-enzymatic bioactivation of the nitrate. Based on insufficient NO release and lack of spectroscopic evidence for formation of NO-sGC, the cysteine (Cys)-dependent activation of sGC by GTN was proposed to occur in an NO-independent manner. This extraordinary claim is questioned by the present findings. First, the effect of GTN/Cys was blocked by the NO scavenger oxyhaemoglobin, the superoxide-generating compound flavin mononucleotide and the haem-site sGC inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one). Secondly, at equi-effective concentrations, GTN/Cys and the NO donor 2,2-diethyl-1-nitroso-oxyhydrazine released identical amounts of NO. Finally, at sufficiently high rates of NO release, activation of sGC by GTN/Cys was accompanied by a shift of the Soret band from 431 to 399 nm, indicating formation of NO-sGC. In the absence of Cys, GTN caused haem oxidation, apparent as a shift of the Soret band to 392 nm, which was accompanied by inactivation of the NO-stimulated enzyme. These results suggest that the effect of GTN/Cys is the result of an activation/inactivation equilibrium that is controlled by the rate of NO release and haem oxidation.
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Affiliation(s)
- Antonius C F Gorren
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, A-8010 Graz, Austria
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127
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Dumitrascu R, Weissmann N, Ghofrani HA, Dony E, Beuerlein K, Schmidt H, Stasch JP, Gnoth MJ, Seeger W, Grimminger F, Schermuly RT. Activation of soluble guanylate cyclase reverses experimental pulmonary hypertension and vascular remodeling. Circulation 2006; 113:286-95. [PMID: 16391154 DOI: 10.1161/circulationaha.105.581405] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Severe pulmonary hypertension is a disabling disease with high mortality, characterized by pulmonary vascular remodeling and right heart hypertrophy. Using wild-type and homozygous endothelial nitric oxide synthase (NOS3(-/-)) knockout mice with pulmonary hypertension induced by chronic hypoxia and rats with monocrotaline-induced pulmonary hypertension, we examined whether the soluble guanylate cyclase (sGC) stimulator Bay41-2272 or the sGC activator Bay58-2667 could reverse pulmonary vascular remodeling. METHODS AND RESULTS Both Bay41-2272 and Bay58-2667 dose-dependently inhibited the pressor response of acute hypoxia in the isolated perfused lung system. When wild-type (NOS3(+/+)) or NOS3(-/-) mice were housed under 10% oxygen conditions for 21 or 35 days, both strains developed pulmonary hypertension, right heart hypertrophy, and pulmonary vascular remodeling, demonstrated by an increase in fully muscularized peripheral pulmonary arteries. Treatment of wild-type mice with the activator of sGC, Bay58-2667 (10 mg/kg per day), or the stimulator of sGC, Bay41-2272 (10 mg/kg per day), after full establishment of pulmonary hypertension from day 21 to day 35 significantly reduced pulmonary hypertension, right ventricular hypertrophy, and structural remodeling of the lung vasculature. In contrast, only minor efficacy of chronic sGC activator therapies was noted in NOS3(-/-) mice. In monocrotaline-injected rats with established severe pulmonary hypertension, both compounds significantly reversed hemodynamic and structural changes. CONCLUSIONS Activation of sGC reverses hemodynamic and structural changes associated with monocrotaline- and chronic hypoxia-induced experimental pulmonary hypertension. This effect is partially dependent on endogenous nitric oxide generated by NOS3.
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Affiliation(s)
- Rio Dumitrascu
- Medical Clinic II/V, University Hospital, Giessen, Germany
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128
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129
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Wu L, Wang R. Carbon Monoxide: Endogenous Production, Physiological Functions, and Pharmacological Applications. Pharmacol Rev 2005; 57:585-630. [PMID: 16382109 DOI: 10.1124/pr.57.4.3] [Citation(s) in RCA: 648] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Over the last decade, studies have unraveled many aspects of endogenous production and physiological functions of carbon monoxide (CO). The majority of endogenous CO is produced in a reaction catalyzed by the enzyme heme oxygenase (HO). Inducible HO (HO-1) and constitutive HO (HO-2) are mostly recognized for their roles in the oxidation of heme and production of CO and biliverdin, whereas the biological function of the third HO isoform, HO-3, is still unclear. The tissue type-specific distribution of these HO isoforms is largely linked to the specific biological actions of CO on different systems. CO functions as a signaling molecule in the neuronal system, involving the regulation of neurotransmitters and neuropeptide release, learning and memory, and odor response adaptation and many other neuronal activities. The vasorelaxant property and cardiac protection effect of CO have been documented. A plethora of studies have also shown the importance of the roles of CO in the immune, respiratory, reproductive, gastrointestinal, kidney, and liver systems. Our understanding of the cellular and molecular mechanisms that regulate the production and mediate the physiological actions of CO has greatly advanced. Many diseases, including neurodegenerations, hypertension, heart failure, and inflammation, have been linked to the abnormality in CO metabolism and function. Enhancement of endogenous CO production and direct delivery of exogenous CO have found their applications in many health research fields and clinical settings. Future studies will further clarify the gasotransmitter role of CO, provide insight into the pathogenic mechanisms of many CO abnormality-related diseases, and pave the way for innovative preventive and therapeutic strategies based on the physiologic effects of CO.
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Affiliation(s)
- Lingyun Wu
- Department of Biology, Lakehead University, 955 Oliver Rd., Thunder Bay, Ontario, Canada P7B 5E1
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130
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Derbyshire ER, Tran R, Mathies RA, Marletta MA. Characterization of Nitrosoalkane Binding and Activation of Soluble Guanylate Cyclase. Biochemistry 2005; 44:16257-65. [PMID: 16331986 DOI: 10.1021/bi0515671] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Soluble guanylate cyclase (sGC) is the primary receptor for the signaling agent nitric oxide (NO). Electronic absorption and resonance Raman spectroscopy were used to show that nitrosoalkanes bind to the heme of sGC to form six-coordinate, low-spin complexes. In the sGC-nitrosopentane complex, a band assigned to an Fe-N stretching vibration is observed at 543 cm(-)(1) which is similar to values reported for other six-coordinate NO-bound hemoproteins. Nitrosoalkanes activate sGC 2-6-fold and synergize with YC-1, a synthetic benzylindazole derivative, to activate the enzyme 11-47-fold. In addition, the observed off-rates of nitrosoalkanes from sGC were found to be dependent on the alkyl chain length. A linear correlation was found between the observed off-rates and the alkyl chain length which suggests that the sGC heme has a large hydrophobic distal ligand-binding pocket. Together, these data show that nitrosoalkanes are a novel class of heme-based sGC activators and suggest that heme ligation is a general requirement for YC-1 synergism.
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Affiliation(s)
- Emily R Derbyshire
- Department of Molecular and Cell Biology, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-1460, USA
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131
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Priviero FBM, Baracat JS, Teixeira CE, Claudino MA, De Nucci G, Antunes E. MECHANISMS UNDERLYING RELAXATION OF RABBIT AORTA BY BAY 41-2272, A NITRIC OXIDE-INDEPENDENT SOLUBLE GUANYLATE CYCLASE ACTIVATOR. Clin Exp Pharmacol Physiol 2005; 32:728-34. [PMID: 16173929 DOI: 10.1111/j.1440-1681.2005.04262.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. The compound BAY 41-2272 (5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl]-pyrimidin-4-ylamine) has been described as a potent, nitric oxide (NO)-independent, stimulator of soluble guanylate cyclase. In the present study, the mechanisms underlying the relaxant effect of BAY 41-2272 in endothelium-intact and -denuded precontracted rabbit aortic rings were investigated. 2. Male New Zealand white rabbits were anaesthetized with pentobarbital sodium. Aortic rings were transferred to 10 mL organ baths containing oxygenated and warmed Krebs' solution. Tissues were connected to force-displacement transducers and changes in isometric force were recorded. Aortic rings were precontracted submaximally with phenylephrine (1 micromol/L). 3. The addition of BAY 41-2272 (0.01-10 micromol/L) to the organ bath produced concentration-dependent relaxations of the aortic rings with a higher potency in endothelium-intact (pEC50 6.59 +/- 0.05) compared with endothelium-denuded (pEC50 6.19 +/- 0.04; P < 0.05) preparations. No differences in maximal responses were observed in either preparation. The NO synthesis inhibitor NG-nitro-L-arginine methyl ester (100 micromol/L) produced a 2.1-fold rightward shift in endothelium-intact (P < 0.01) rings, but had no effect in endothelium-denuded rings. The soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 1 micromol/L) caused significant rightward shifts of the concentration-response curves to BAY 41-2272 of 4.9- and 2.6-fold in endothelium-intact and -denuded rings, respectively. The phosphodiesterase-5 inhibitor sildenafil (0.1 micromol/L) significantly potentiated the relaxant effects of BAY 41-2272 in both endothelium-intact and -denuded rings. 4. At 1 micromol/L, BAY 41-2272 significantly elevated the aortic cGMP content above basal levels in both endothelium-intact and -denuded rings. Furthermore, ODQ reduced BAY 41-2272-elicited increases in cGMP content by 17 and 90% in endothelium-intact and -denuded rings, respectively (P < 0.01). 5. In conclusion, BAY 41-2272 potently relaxes endothelium-intact and -denuded rabbit aortic rings. The basal release of endothelium-derived NO enhances BAY 41-2272-induced relaxations, suggesting a synergistic effect of BAY 41-2272 and NO on soluble guanylate cyclase. In addition, the endothelium-independent relaxation involves both GMP-dependent and -independent mechanisms.
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Affiliation(s)
- Fernanda B M Priviero
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil
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132
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Che Y, Ellis A, Li CG. Enhanced responsiveness to nitric oxide, nitroxyl anions, and nitrergic transmitter by 3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole in the rat anococcygeus muscle. Nitric Oxide 2005; 13:118-24. [PMID: 15993633 DOI: 10.1016/j.niox.2005.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 04/08/2005] [Accepted: 05/17/2005] [Indexed: 11/24/2022]
Abstract
The effects of 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) on responses to sodium nitroprusside (SNP), S-nitroso-N-acetyl-penicillamine (SNAP), the nitroxyl anion donor Angeli's salt, and nitrergic nerve stimulation, as well as the release of NO from nitrergic nerves, were studied in the rat isolated anococcygeus muscle. YC-1 (1-100 microM) produced concentration-dependent relaxations in contracted muscles, which were partially but significantly reduced by the inhibitor of soluble guanylate cyclase (sGC), 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ, 1 and 10 microM). At a concentration that did not affect tissue tension, YC-1 (1 microM) significantly enhanced relaxations to SNP, SNAP, and Angeli's salt but did not affect relaxations to papaverine (10 microM). Nitrergic relaxations elicited by short periods (1 Hz for 10 s, 15 V) and long periods of EFS (5 Hz for 5 min, 15 V) were also enhanced by YC-1. YC-1 (100 microM), in an l-NAME and tetrodotoxin-insensitive manner, also increased the amount of NO detected in the organ bath media after the tissue was field stimulated (5 Hz for 5 min), which may have resulted from the electrolytic degradation of YC-1, as this effect was also seen in the absence of tissue. In summary, YC-1 enhanced relaxations to donors of NO, Angeli's salt, and nitrergic nerve stimulation in the rat anococcygeus muscle; however, the enhanced release of NO by YC-1 following nitrergic nerve stimulation was not a tissue-dependent effect.
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Affiliation(s)
- Yan Che
- School of Health Sciences, RMIT University, P.O. Box 71, Bundoora, Vic. 3083, Australia
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133
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Cary SPL, Winger JA, Marletta MA. Tonic and acute nitric oxide signaling through soluble guanylate cyclase is mediated by nonheme nitric oxide, ATP, and GTP. Proc Natl Acad Sci U S A 2005; 102:13064-9. [PMID: 16131543 PMCID: PMC1201615 DOI: 10.1073/pnas.0506289102] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nitric oxide (NO) affects many physiological systems by activating cGMP signaling cascades through soluble guanylate cyclase (sGC). In the accepted model, NO binds to the sGC heme, activating the enzyme. Here, we report that in the presence of physiological concentrations of ATP and GTP, NO dissociation from the sGC heme is approximately 160 times slower than the rate of enzyme deactivation in vitro. Deactivated sGC still has NO bound to the heme, and full activation requires additional NO. We propose an activation model where, in the presence of both ATP and GTP, tonic NO forms a stable heme complex with low sGC activity; acute production of NO transiently and fully activates this NO-bound sGC.
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Affiliation(s)
- Stephen P L Cary
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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134
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Pyriochou A, Papapetropoulos A. Soluble guanylyl cyclase: more secrets revealed. Cell Signal 2005; 17:407-13. [PMID: 15601619 DOI: 10.1016/j.cellsig.2004.09.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2004] [Accepted: 09/10/2004] [Indexed: 11/25/2022]
Abstract
Guanylyl cyclases (GCs) are enzymes that convert guanosine-5'-triphosphate (GTP) to cyclic guanosine-3',5'-monophosphate (cGMP). The second messenger cGMP participates in signaling by (1) stimulating the activity of kinases that belong to the protein kinase G family, (2) altering the conductance of cGMP-gated ion channels and (3) changing the activity of cGMP-regulated phosphodiesterases. In contrast to adenylyl cyclases which exist as membrane-bound molecules, guanylyl cyclases (GC) occur in both membrane-bound and cytosolic forms. The particulate GC (pGC) isoforms serve as receptors for natriuretic peptides, while soluble GC (sGC) is the "receptor" for nitric oxide (NO). In addition to the difference in ligands and subcellular organization, the two forms of GC also differ in that pGC exists in homodimeric form, while typically sGC occurs as a heterodimer. Herein, we will review the literature on sGC subunit structure and discuss the regulation of the enzyme at the transcriptional and post-translational level.
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Affiliation(s)
- Anastasia Pyriochou
- Laboratory for Molecular Pharmacology, School of Pharmacy, University of Patras, 26504 Patras, Greece
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135
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Li Z, Pal B, Takenaka S, Tsuyama S, Kitagawa T. Resonance Raman evidence for the presence of two heme pocket conformations with varied activities in CO-bound bovine soluble guanylate cyclase and their conversion. Biochemistry 2005; 44:939-46. [PMID: 15654750 DOI: 10.1021/bi0489208] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Resonance Raman (RR) spectra of soluble guanylate cyclase (sGC) reported by five independent research groups have been classified as two types: sGC(1) and sGC(2). Here we demonstrate that the RR spectra of sGC isolated from bovine lung contain only sGC(2) while both species are observed in the spectra of the CO-bound form (CO-sGC). The relative populations of the two forms were altered from an initial composition in which the CO-sGC(2) form predominated, with the Fe-CO (nu(Fe)(-)(CO)) and C-O stretching modes (nu(CO)) at 472 and 1985 cm(-)(1), respectively, to a composition dominated by the CO-sGC(1) form with nu(Fe)(-)(CO) and nu(CO) at 488 and 1969 cm(-)(1), respectively, following the addition of a xenobiotic, YC-1. Further addition of a substrate, GTP, completed the change. GDP and cGMP had a significantly weaker effect, while a substrate analogue, GTP-gamma-S, had an effect similar to that of GTP. In contrast, ATP had a reverse effect, and suppressed the effects of YC-1 and GTP. In the presence of both YC-1 and GTP, vinyl vibrations of heme were significantly influenced. New CO isotope-sensitive bands were observed at 521, 488, 363, and 227 cm(-)(1). The 521 cm(-)(1) band was assigned to the five-coordinate (5c) species from the model compound studies using ferrous iron protoporphyrin IX in CTAB micelles. Distinct from the 472 cm(-)(1) species, both the 488 and 521 cm(-)(1) species were apparently un-photodissociable when an ordinary Raman spinning cell was used, indicating rapid recombination of photodissociated CO. On the basis of these findings, binding of YC-1 to the heme pocket is proposed.
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Affiliation(s)
- Zhengqiang Li
- Okazaki Institute for Integrative Bioscience, National Institute of Natural Sciences, Myodaiji, Okazaki 444-8787, Japan
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136
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Schmidt PM, Rothkegel C, Wunder F, Schröder H, Stasch JP. Residues stabilizing the heme moiety of the nitric oxide sensor soluble guanylate cyclase. Eur J Pharmacol 2005; 513:67-74. [PMID: 15878710 DOI: 10.1016/j.ejphar.2005.02.046] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Revised: 02/23/2005] [Accepted: 02/25/2005] [Indexed: 10/25/2022]
Abstract
Soluble guanylate cyclase, a heterodimer consisting of an alpha- and a heme-containing beta-subunit, is the major receptor for the biological messenger nitric oxide (NO) and is involved in various signal transduction pathways. The heme moiety of the enzyme is bound between the axial heme ligand histidine(105) and the recently identified counterparts of the heme propionic acids, tyrosine(135) and arginine(139). The latter residues together with an invariant serine(137) form the unique heme binding motif Y-x-S-x-R. In this work, we show that replacement of the serine(137) with alanine destabilizes the binding of the heme moiety and impairs NO-mediated soluble guanylate cyclase activation.
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Affiliation(s)
- Peter M Schmidt
- Institute of Cardiovascular Research, Bayer Healthcare, Wuppertal, Germany.
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137
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Boon EM, Marletta MA. Ligand specificity of H-NOX domains: from sGC to bacterial NO sensors. J Inorg Biochem 2005; 99:892-902. [PMID: 15811506 DOI: 10.1016/j.jinorgbio.2004.12.016] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Revised: 11/26/2004] [Accepted: 12/17/2004] [Indexed: 11/20/2022]
Abstract
Soluble guanylate cyclase (sGC) is a nitric oxide (NO) sensing hemoprotein that has been found in eukaryotes from Drosophila to humans. Prokaryotic proteins with significant homology to the heme domain of sGC have recently been identified through genomic analysis. This family of heme proteins has been named the H-NOX domain, for Heme-Nitric oxide/OXygen binding domain. The key observation from initial studies in this family is that some members, those proteins from most eukaryotes and facultative aerobic prokaryotes, bind NO in a five-coordinate heme complex, but do not bind oxygen (O(2)), the same ligand binding characteristics as sGC. H-NOX family members from obligate aerobic prokaryotes bind O(2) and NO in six-coordinate complexes, similar to the globins and other O(2)-sensing heme proteins. The molecular factors that contribute to these differences in ligand specificity, within a family of sequence related proteins, are the subject of this review.
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Affiliation(s)
- Elizabeth M Boon
- Department of Chemistry, Lawrence Berkeley National Laboratory, University of California-Berkeley, Berkeley, CA 94705-1460, USA
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138
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Pan SL, Guh JH, Peng CY, Wang SW, Chang YL, Cheng FC, Chang JH, Kuo SC, Lee FY, Teng CM. YC-1 [3-(5′-Hydroxymethyl-2′-furyl)-1-benzyl Indazole] Inhibits Endothelial Cell Functions Induced by Angiogenic Factors in Vitro and Angiogenesis in Vivo Models. J Pharmacol Exp Ther 2005; 314:35-42. [PMID: 15784655 DOI: 10.1124/jpet.105.085126] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Angiogenesis is a process that involves endothelial cell proliferation, migration, invasion, and tube formation, and inhibition of these processes has implications for angiogenesis-mediated disorders. The purpose of this study was to evaluate the antiangiogenic efficacy of YC-1 [3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole] in well characterized in vitro and in vivo systems. YC-1 inhibited the ability of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in a dose-dependent manner to induce proliferation, migration, and tube formation in human umbilical vascular endothelial cells; these outcomes were evaluated using [3H]thymidine incorporation, transwell chamber, and Matrigel-coated slide assays, respectively. YC-1 inhibited VEGF- and bFGF-induced p42/p44 mitogen-activated protein kinase and Akt phosphorylation as well as protein kinase C alpha translocation using Western blot analysis. The effect of YC-1 on angiogenesis in vivo was evaluated using the mouse Matrigel implant model. YC-1 administered orally in doses of 1 to 100 mg/kg/day inhibited VEGF- and bFGF-induced neovascularization in a dose-dependent manner over 7 days. These results indicate that YC-1 has antiangiogenic activity at very low doses. Moreover, in transplantable murine tumor models, YC-1 administered orally displayed a high degree of antitumor activity (treatment-to-control life span ratio > 175%) without cytotoxicity. YC-1 may be useful for treating angiogenesis-dependent human diseases such as cancer.
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Affiliation(s)
- Shiow-Lin Pan
- Pharmacological Institute, College of Medicine, National Taiwan University, 1 Jen-Ai Road, Section 1, Taipei, Taiwan
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139
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Wu CH, Chang WC, Chang GY, Kuo SC, Teng CM. The inhibitory mechanism of YC-1, a benzyl indazole, on smooth muscle cell proliferation: an in vitro and in vivo study. J Pharmacol Sci 2005; 94:252-60. [PMID: 15037810 DOI: 10.1254/jphs.94.252] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The pharmacological mechanisms of a synthetic compound 1-benzyl-3-(5'-hydroxymethyl-2'-furyl) indazole (YC-1) in preventing smooth muscle cell proliferation remains to be elucidated. The present study was aimed to explore the effects of YC-1 on certain molecules responsible for cell proliferation, including transforming growth factor (TGF)-beta1, soluble guanylyl cyclase (sGC) and focal adhesion kinase (FAK). The in vivo assay was correlated to the in vitro results of YC-1 on vascular stenosis. YC-1 was applied topically via a pluronic gel onto the balloon-injured rat carotid arteries, which were then harvested two weeks later for histological analysis. Our in vitro results showed that TGF-beta1 was suppressed by YC-1 by 50%. The translational level of sGC was threefold activated by YC-1 while the transcription level of sGC was increased up to 24-fold. FAK, the molecule responsible for cell proliferation and migration, was suppressed by YC-1 on the translational levels for 72%. These in vitro results were in consistent with the in vivo observation that the area ratio of neointima to media was reduced by YC-1. This study provides insights into the pharmacological mechanisms of YC-1 in preventing abnormal smooth muscle cell proliferation and thus supports the use of YC-1 as an adjuvant therapy for balloon injury-induced restenosis.
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MESH Headings
- Administration, Topical
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Carotid Artery, Common/pathology
- Catheterization/adverse effects
- Cell Division/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- Focal Adhesion Kinase 1
- Focal Adhesion Protein-Tyrosine Kinases
- Glyceraldehyde-3-Phosphate Dehydrogenases/drug effects
- Glyceraldehyde-3-Phosphate Dehydrogenases/genetics
- Guanylate Cyclase/drug effects
- Guanylate Cyclase/genetics
- Guanylate Cyclase/metabolism
- Imidazoles/chemistry
- Imidazoles/pharmacology
- Indazoles/administration & dosage
- Indazoles/chemistry
- Indazoles/pharmacokinetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/growth & development
- Poloxamer/chemistry
- Poloxamer/metabolism
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Protein-Tyrosine Kinases/drug effects
- Protein-Tyrosine Kinases/genetics
- RNA, Messenger
- Rats
- Receptors, Enterotoxin
- Receptors, Guanylate Cyclase-Coupled
- Receptors, Peptide/drug effects
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Transforming Growth Factor beta/antagonists & inhibitors
- Transforming Growth Factor beta/metabolism
- Tunica Intima/drug effects
- Tunica Intima/growth & development
- Tunica Intima/pathology
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Affiliation(s)
- Chieh-Hsi Wu
- Department of Pharmacology, China Medical University, Taichung, Taiwan.
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140
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Chien WL, Liang KC, Teng CM, Kuo SC, Lee FY, Fu WM. Enhancement of learning behaviour by a potent nitric oxide-guanylate cyclase activator YC-1. Eur J Neurosci 2005; 21:1679-88. [PMID: 15845095 DOI: 10.1111/j.1460-9568.2005.03993.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Memory is one of the most fundamental mental processes, and various approaches have been used to understand the mechanisms underlying this process. Nitric oxide (NO), cGMP and protein kinase G (PKG) are involved in the modulation of synaptic plasticity in various brain regions. YC-1, which is a benzylindazole derivative, greatly potentiated the response of soluble guanylate cyclase to NO (up to several hundreds fold). We have previously shown that YC-1 markedly enhances long-term potentiation in hippocampal and amygdala slices via NO-cGMP-PKG-dependent pathway. We here further investigated whether YC-1 promotes learning behaviour in Morris water maze and avoidance tests. It was found that YC-1 shortened the escape latency in the task of water maze, increased and decreased the retention scores in passive and active avoidance task, respectively. Administration of YC-1 30 min after foot-shock stimulation did not significantly affect retention scores in response to passive avoidance test. Administration of scopolamine, a muscarinic antagonist, markedly impaired the memory acquisition. Pretreatment of YC-1 inhibited the scopolamine-induced learning deficit. The enhancement of learning behaviour by YC-1 was antagonized by intracerebroventricular injection of NOS inhibitor L-NAME and PKG inhibitors of KT5823 and Rp-8-Br-PET-cGMPS, indicating that NO-cGMP-PKG pathway is also involved in the learning enhancement action of YC-1. YC-1 is thus a good drug candidate for the improvement of learning and memory.
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Affiliation(s)
- Wei-Lin Chien
- Pharmacological Institute, College of Medicine, National Taiwan University, No. 1, Sec. 1, Jen-Ai Road, Taipei, Taiwan
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141
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Wang JP, Chen YS, Tsai CR, Huang LJ, Kuo SC. The blockade of cyclopiazonic acid-induced store-operated Ca2+ entry pathway by YC-1 in neutrophils. Biochem Pharmacol 2005; 68:2053-64. [PMID: 15476676 DOI: 10.1016/j.bcp.2004.07.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2004] [Accepted: 07/09/2004] [Indexed: 10/26/2022]
Abstract
In the presence of external Ca2+, pretreatment of neutrophils with 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) inhibited the cyclopiazonic acid (CPA)-induced [Ca2+](i) elevation in a concentration- but not a time-dependent manner, while YC-1 had no effect on the Ca2+ signals in a Ca2+-free medium. YC-1 failed to inhibit ATP- and interleukin-8 (IL-8)-induced [Ca2+](i) changes. Addition of YC-1 after cell activation strongly inhibited the CPA-induced [Ca2+](i) changes. In a classical Ca2+ readdition protocol, a similar extent inhibition of Ca2+ spike by YC-1 introduced either prior to or after CPA stimulation was obtained. In rat neutrophils, mRNA for endothelial differentiation gene (edg)1, edg5, edg6 and edg8, the putative targets for sphingosine 1-phosphate (S1P), could be detected. However, S1P was found to have little effect on Ca(2+) signals. YC-1 did not inhibit but enhanced the sphingosine-induced [Ca2+](i) changes. Inhibition by YC-1 of CPA-induced [Ca2+](i) changes was not prevented by 7-nitroindazole and N-(3-aminomethyl)benzylacetamidine (1400W), two nitric oxide synthase (NOS) inhibitors, by aristolochic acid, a phospholipase A(2) inhibitor, or by suspension in a Na(+)-deprived medium. YC-1 did not affect the mitochondrial membrane potential. Moreover, YC-1 did not alter [Ca2+](i) changes in response to ionomycin after CPA and formyl-Met-Leu-Phe (fMLP) stimulation in a Ca2+-free medium. YC-1 had no effect on the basal [Ca2+](i) level, the pharmacologically isolated plasma membrane Ca2+-ATPase activity, and Ba2+ entry into CPA-activated cells. YC-1 alone resulted in the accumulation of actin filaments in neutrophils, while significantly reduced the intensity of actin filament staining in the subsequent activation with CPA. These results indicate that YC-1 inhibited CPA-activated store-operated Ca2+ entry (SOCE) probably through the direct blockade of channel activation and/or the disruption of the integrity of the actin cytoskeleton necessary for supporting Ca2+ entry pathway in neutrophils.
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Affiliation(s)
- Jih-Pyang Wang
- Department of Education and Research, Taichung Veterans General Hospital, Taichung 407, Taiwan, Republic of China.
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142
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Bainbridge SA, Sidle EH, Smith GN. Direct placental effects of cigarette smoke protect women from pre-eclampsia: the specific roles of carbon monoxide and antioxidant systems in the placenta. Med Hypotheses 2005; 64:17-27. [PMID: 15533604 DOI: 10.1016/j.mehy.2004.06.019] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Accepted: 06/17/2004] [Indexed: 01/24/2023]
Abstract
Pre-eclampsia is a hypertensive disorder of pregnancy characterized by shallow placentation, inadequate placental perfusion, localized placental oxidative stress, a heightened maternal inflammatory response and subsequent maternal endothelial dysfunction. This pathophysiology leads to an increase in maternal blood pressure, edema and proteinurea. Interestingly, women who smoke cigarettes throughout pregnancy are at a 33% reduced risk of developing this disorder. The exact mechanisms through which cigarette smoke reduces the risk of pre-eclampsia are not yet understood. We propose that cigarette smoke reduces the risk of developing pre-eclampsia via direct placental effects. In this review we will address, and provide evidence for, our specific hypotheses that: (a) CO increases trophoblast invasion and spiral arteriole remodeling; (b) CO decreases a localized inflammatory response at the level of the decidua; (c) CO increases utero-placental, intra-placental and feto-placental blood flow; (d) CO decreases hypoxia-induced apoptosis of the syncitiotrophoblast layer; (e) CO activates hemoproteins involved in normal endothelial functioning normally acted upon by NO; (f) compound(s) within cigarette smoke result in upregulation of antioxidant systems within the placenta. These various mechanisms of action must be further examined as they may provide valuable keys to novel therapeutic design in the realm of pre-eclampsia research.
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Affiliation(s)
- Shannon A Bainbridge
- Department of Anatomy and Cell Biology, Faculty of Health Sciences, Botterell Hall, Queen's University, Kingston, Ont., Canada K7L 3N6.
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143
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Aziz MTA, El-Asmar MF, Mostafa T, Atta H, Wassef MAA, Fouad HH, Roshdy NK, Rashed LA, Sabry D. Effects of Nitric Oxide Synthase and Heme Oxygenase Inducers and Inhibitors on Molecular Signaling of Erectile Function. J Clin Biochem Nutr 2005. [DOI: 10.3164/jcbn.37.103] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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144
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Pal B, Kitagawa T. Interactions of soluble guanylate cyclase with diatomics as probed by resonance Raman spectroscopy. J Inorg Biochem 2005; 99:267-79. [PMID: 15598506 DOI: 10.1016/j.jinorgbio.2004.09.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Revised: 09/24/2004] [Accepted: 09/27/2004] [Indexed: 10/26/2022]
Abstract
Soluble guanylate cyclase (sGC, EC 4.6.1.2) acts as a sensor for nitric oxide (NO), but is also activated by carbon monoxide in the presence of an allosteric modulator. Resonance Raman studies on the structure-function relations of sGC are reviewed with a focus on the CO-adduct in the presence and absence of allosteric modulator, YC-1, and substrate analogues. It is demonstrated that the sGC isolated from bovine lung contains one species with a five-coordinate (5c) ferrous high-spin heme with the Fe-His stretching mode at 204 cm(-1), but its CO adduct yields two species with different conformations about the heme pocket with the Fe-CO stretching (nuFe-CO) mode at 473 and 489 cm(-1), both of which are His- and CO-coordinated 6c ferrous adducts. Addition of YC-1 to it changes their population and further addition of GTP yields one kind of 6c (nuFe-CO=489 cm(-1)) in addition to 5c CO-adduct (nuFe-CO=521 cm(-1)). Under this condition the enzymatic activity becomes nearly the same level as that of NO adduct. Addition of gamma-S-GTP yields the same effect as GTP does but cGMP and GDP gives much less effects. Unexpectedly, ATP cancels the effects of GTP. The structural meaning of these spectroscopic observations is discussed in detail.
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Affiliation(s)
- Biswajit Pal
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Higashiyama 5-1, Okazaki 444-8787, Japan
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145
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Motterlini R, Sawle P, Hammad J, Bains S, Alberto R, Foresti R, Green CJ. CORM‐A1: a new pharmacologically active carbon monoxide‐releasing molecule. FASEB J 2004; 19:284-6. [PMID: 15556971 DOI: 10.1096/fj.04-2169fje] [Citation(s) in RCA: 298] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Carbon monoxide (CO) is emerging as an important and versatile mediator of physiological processes to the extent that treatment of animals with exogenous CO gas has beneficial effects in a range of vascular- and inflammatory-related disease models. The recent discovery that certain transition metal carbonyls function as CO-releasing molecules (CO-RMs) in biological systems highlighted the potential of exploiting this and similar classes of compounds as a stratagem to deliver CO for therapeutic purposes. Here we describe the biochemical features and pharmacological actions of a newly identified water-soluble CO releaser (CORM-A1) that, unlike the first prototypic molecule recently described (CORM-3), does not contain a transition metal and liberates CO at a much slower rate under physiological conditions. Using a myoglobin assay and an amperometric CO electrode, we demonstrated that the release of CO from CORM-A1 is both pH- and temperature-dependent with a half-life of approximately 21 min at 37 degrees C and pH 7.4. In isolated aortic rings, CORM-A1 promoted a gradual but profound concentration-dependent vasorelaxation over time, which was highly amplified by YC-1 (1 microM) and attenuated by ODQ, a stimulator and inhibitor of guanylate cyclase, respectively. Similarly, administration of CORM-A1 (30 micromol/kg i.v.) in vivo produced a mild decrease in mean arterial pressure, which was markedly potentiated by pretreatment with YC-1 (1.2 micromol/kg i.v.). Interestingly, an inactive form of CORM-A1 that is incapable of releasing CO failed to promote both vasorelaxation and hypotension, thus directly implicating CO as the mediator of the observed pharmacological effects. Our results reveal that the bioactivities exerted by CORM-A1 reflect its intrinsic biochemical behavior of a slow CO releaser, which may be advantageous in the treatment of chronic conditions that require CO to be delivered in a carefully controlled manner.
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Affiliation(s)
- Roberto Motterlini
- Vascular Biology Unit, Department of Surgical Research, Northwick Park Institute for Medical Research, Harrow, Middlesex, UK.
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146
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Ott SR, Delago A, Elphick MR. An evolutionarily conserved mechanism for sensitization of soluble guanylyl cyclase reveals extensive nitric oxide-mediated upregulation of cyclic GMP in insect brain. Eur J Neurosci 2004; 20:1231-44. [PMID: 15341595 DOI: 10.1111/j.1460-9568.2004.03588.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Soluble guanylyl cyclase (SGC) is the main receptor for the gaseous signalling molecule nitric oxide (NO) in vertebrates and invertebrates. Recently, a novel class of drugs that regulate mammalian SGC by NO-independent allosteric mechanisms has been identified [e.g. 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole, YC-1]. To assess the evolutionary conservation and hence the potential physiological relevance of these mechanisms, we have tested YC-1 on the brains of two model insects, the cockroach Periplaneta americana and the locust Schistocerca gregaria. YC-1 strongly potentiated the NO-induced elevation of total cyclic 3',5'-guanosine monophosphate (cGMP) and amplified the intensity and consistency of NO-induced cGMP-immunoreactivity in the brain. Our data indicate that the effect of YC-1 was independent of phosphodiesterase inhibition and thus mediated by direct sensitization of SGC. Immunohistopharmacology and co-labelling with antibodies against the SGC alpha-subunit confirmed that cGMP induced by co-application of NO and YC-1 is predominantly attributable to SGC. The staggering number of NO-responsive neurons revealed by YC-1 suggests that previous studies may have considerably underestimated the number of cellular targets for NO in the insect brain. Moreover, a subset of these targets exhibited cGMP-immunoreactivity without application of exogenous NO, demonstrating that YC-1 can be exploited for visualization of physiological cGMP signals in response to endogenous NO production. In conclusion, our discovery that YC-1 is a potent sensitizer of insect SGC indicates that a NO-independent regulatory site is an evolutionarily conserved feature of SGC. Our findings add considerable momentum to the concept of an as yet unidentified endogenous ligand that regulates the gain of the NO-cGMP signalling pathway.
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Affiliation(s)
- Swidbert R Ott
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, E1 4NS, UK.
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147
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Abstract
Carbon monoxide (CO) has long been known to have dramatic physiological effects on organisms ranging from bacteria to humans, but recently there have a number of suggestions that organisms might have specific sensors for CO. This article reviews the current evidence for a variety of proteins with demonstrated or potential CO-sensing ability. Particular emphasis is placed on the molecular description of CooA, a heme-containing CO sensor from Rhodospirillum rubrum, since its biological role as a CO sensor is clear and we have substantial insight into the basis of its sensing ability.
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Affiliation(s)
- Gary P Roberts
- Department of Bacteriology, 420 Henry Mall, University of Wisconsin-Madison, Madison, WI 53706, USA.
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148
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Balashova N, Chang FJ, Lamothe M, Sun Q, Beuve A. Characterization of a novel type of endogenous activator of soluble guanylyl cyclase. J Biol Chem 2004; 280:2186-96. [PMID: 15509556 DOI: 10.1074/jbc.m411545200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Nitric oxide (NO) remains the only firmly established endogenous modulator of soluble guanylyl cyclase (sGC) activity, but physiological, structural, and biochemical evidence now suggests that in vivo regulation of sGC involves direct interaction with other factors. We searched for such endogenous modulators in human umbilical vein endothelial cells and COS-7 cells. The cytosolic fraction of both cell types stimulated the activity of semipurified sGC severalfold in the absence or presence of a saturating concentration of NO. The cytosolic factor was sensitive to proteinase K and destroyed by boiling, suggesting that it contains a protein component. Size exclusion chromatography revealed peaks of activity between 40 and 70 kDa. The sGC-activating effect was further purified by ion exchange chromatography. In the presence of the benzylindazole YC-1 or NO, the partially purified factor synergistically activated sGC, suggesting that this factor had a mode of activation different from that of YC-1 or NO. Four candidate activators were identified from the final purification step by matrix-assisted laser desorption ionization mass spectrometry analysis. Using an sGC affinity matrix, one of them, the molecular chaperone Hsp70, was shown to directly interact with sGC. This interaction was further confirmed by co-immunoprecipitation in lung tissues and by co-localization in smooth muscle cells. sGC and Hsp70 co-localized at the plasma membrane, supporting the idea that sGC can be translocated to the membrane. Hsp70 co-purifies with the sGC-activating effect, and immunodepletion of Hsp70 from COS-7 cytosol coincided with a marked attenuation of the sGC-activating effect, yet the effect was not rescued by the addition of pure Hsp70. Thus, Hsp70 is a novel sGC-interacting protein that is responsible for the sGC-activating effect, probably in association with other factors or after covalent modification.
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Affiliation(s)
- Nataliya Balashova
- Department of Pharmacology and Physiology, New Jersey Medical School, UMDNJ, Newark, New Jersey 07103, USA
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149
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Koesling D, Russwurm M, Mergia E, Mullershausen F, Friebe A. Nitric oxide-sensitive guanylyl cyclase: structure and regulation. Neurochem Int 2004; 45:813-9. [PMID: 15312975 DOI: 10.1016/j.neuint.2004.03.011] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
By the formation of the second messenger cGMP, NO-sensitive guanylyl cyclase (GC) plays a key role within the NO/cGMP signaling cascade which participates in vascular regulation and neurotransmission. The enzyme contains a prosthetic heme group that acts as the acceptor site for NO. High affinity binding of NO to the heme moiety leads to an up to 200-fold activation of the enzyme. Unexpectedly, NO dissociates with a half-life of a few seconds which appears fast enough to account for the deactivation of the enzyme in biological systems. YC-1 and its analogs act as NO sensitizers and led to the discovery of a novel pharmacologically and conceivably physiologically relevant regulatory principle of the enzyme. The two isoforms of the heterodimeric enzyme (alpha1beta1, alpha2beta1) are known that are functionally indistinguishable. The alpha2beta1-isoform mainly occurs in brain whereas the alpha1beta1-enzyme shows a broader distribution and represents the predominantly expressed form of NO-sensitive GC. Until recently, the enzyme has been thought to occur in the cytosol. However, latest evidence suggests that the alpha2-subunit mediates the membrane association of the alpha2beta1-isoform via interaction with a PDZ domain of the post-synaptic scaffold protein PSD-95. Binding to PSD-95 locates this isoform in close proximity to the NO-generating synthases thereby enabling the NO sensor to respond to locally elevated NO concentrations. In sum, the two known isoforms may stand for the neuronal and vascular form of NO-sensitive GC reflecting a possible association to the neuronal and endothelial NO-synthase, respectively.
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Affiliation(s)
- Doris Koesling
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät MA N1, Ruhr-Universität Bochum, 44780 Bochum, Germany.
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150
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Evgenov OV, Ichinose F, Evgenov NV, Gnoth MJ, Falkowski GE, Chang Y, Bloch KD, Zapol WM. Soluble guanylate cyclase activator reverses acute pulmonary hypertension and augments the pulmonary vasodilator response to inhaled nitric oxide in awake lambs. Circulation 2004; 110:2253-9. [PMID: 15466650 DOI: 10.1161/01.cir.0000144469.01521.8a] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Inhaled nitric oxide (NO) is a potent and selective pulmonary vasodilator, which induces cGMP synthesis by activating soluble guanylate cyclase (sGC) in ventilated lung regions. Carbon monoxide (CO) has also been proposed to influence smooth muscle tone via activation of sGC. We examined whether direct stimulation of sGC by BAY 41-2272 would produce pulmonary vasodilation and augment the pulmonary responses to inhaled NO or CO. METHODS AND RESULTS In awake, instrumented lambs, the thromboxane analogue U-46619 was intravenously administered to increase mean pulmonary arterial pressure to 35 mm Hg. Intravenous infusion of BAY 41-2272 (0.03, 0.1, and 0.3 mg x kg(-1) x h(-1)) reduced mean pulmonary arterial pressure and pulmonary vascular resistance and increased transpulmonary cGMP release in a dose-dependent manner. Larger doses of BAY 41-2272 also produced systemic vasodilation and elevated the cardiac index. N(omega)-nitro-l-arginine methyl ester abolished the systemic but not the pulmonary vasodilator effects of BAY 41-2272. Furthermore, infusing BAY 41-2272 at 0.1 mg x kg(-1) x h(-1) potentiated and prolonged the pulmonary vasodilation induced by inhaled NO (2, 10, and 20 ppm). In contrast, inhaled CO (50, 250, and 500 ppm) had no effect on U-46619-induced pulmonary vasoconstriction before or during administration of BAY 41-2272. CONCLUSIONS In lambs with acute pulmonary hypertension, BAY 41-2272 is a potent pulmonary vasodilator that augments and prolongs the pulmonary vasodilator response to inhaled NO. Direct pharmacological stimulation of sGC, either alone or in combination with inhaled NO, may provide a novel approach for the treatment of pulmonary hypertension.
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Affiliation(s)
- Oleg V Evgenov
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, CLN 309, Boston, Mass 02114, USA.
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