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Wölkart G, Stessel H, Fassett E, Teschl E, Friedl K, Trummer M, Schrammel A, Kollau A, Mayer B, Fassett J. Adenosine kinase (ADK) inhibition with ABT-702 induces ADK protein degradation and a distinct form of sustained cardioprotection. Eur J Pharmacol 2022; 927:175050. [PMID: 35618039 DOI: 10.1016/j.ejphar.2022.175050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 11/18/2022]
Abstract
Pharmacological inhibition of adenosine kinase (ADK), the major route of myocardial adenosine metabolism, can elicit acute cardioprotection against ischemia-reperfusion (IR) by increasing adenosine signaling. Here, we identified a novel, extended effect of the ADK inhibitor, ABT-702, on cardiac ADK protein longevity and investigated its impact on sustained adenosinergic cardioprotection. We found that ABT-702 treatment significantly reduced cardiac ADK protein content in mice 24-72 h after administration (IP or oral). ABT-702 did not alter ADK mRNA levels, but strongly diminished (ADK-L) isoform protein content through a proteasome-dependent mechanism. Langendorff perfusion experiments revealed that hearts from ABT-702-treated mice maintain higher adenosine release long after ABT-702 tissue elimination, accompanied by increased basal coronary flow (CF) and robust tolerance to IR. Sustained cardioprotection by ABT-702 did not involve increased nitric oxide synthase expression, but was completely dependent upon increased adenosine release in the delayed phase (24 h), as indicated by the loss of cardioprotection and CF increase upon perfusion of adenosine deaminase or adenosine receptor antagonist, 8-phenyltheophylline. Importantly, blocking adenosine receptor activity with theophylline during ABT-702 administration prevented ADK degradation, preserved late cardiac ADK activity, diminished CF increase and abolished delayed cardioprotection, indicating that early adenosine receptor signaling induces late ADK degradation to elicit sustained adenosine release. Together, these results indicate that ABT-702 induces a distinct form of delayed cardioprotection mediated by adenosine receptor-dependent, proteasomal degradation of cardiac ADK and enhanced adenosine signaling in the late phase. These findings suggest ADK protein stability may be pharmacologically targeted to achieve sustained adenosinergic cardioprotection.
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Affiliation(s)
- Gerald Wölkart
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria
| | - Heike Stessel
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria
| | - Erin Fassett
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria
| | - Eva Teschl
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria
| | - Katrin Friedl
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria
| | - Modesta Trummer
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria
| | - Astrid Schrammel
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria
| | - Alexander Kollau
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria
| | - Bernd Mayer
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria
| | - John Fassett
- Department of Pharmacology and Toxicology, University of Graz, 8010, Graz, Austria.
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Mussbacher M, Stessel H, Pirker T, Gorren ACF, Mayer B, Schrammel A. Author Correction: S-nitrosoglutathione inhibits adipogenesis in 3T3-L1 preadipocytes by S-nitrosation of CCAAT/enhancer-binding protein β. Sci Rep 2020; 10:9846. [PMID: 32528086 PMCID: PMC7289844 DOI: 10.1038/s41598-020-67063-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Marion Mussbacher
- Department of Pharmacology and Toxicology, University of Graz, Humboldtstraße 46, A-8010, Graz, Austria.,Center for Physiology and Pharmacology, Department of Vascular Biology and Thrombosis Research, Medical University of Vienna, Schwarzspanierstraβe 17, A-1090, Vienna, Austria
| | - Heike Stessel
- Department of Pharmacology and Toxicology, University of Graz, Humboldtstraße 46, A-8010, Graz, Austria
| | - Teresa Pirker
- Department of Pharmacology and Toxicology, University of Graz, Humboldtstraße 46, A-8010, Graz, Austria
| | - Antonius C F Gorren
- Department of Pharmacology and Toxicology, University of Graz, Humboldtstraße 46, A-8010, Graz, Austria
| | - Bernd Mayer
- Department of Pharmacology and Toxicology, University of Graz, Humboldtstraße 46, A-8010, Graz, Austria
| | - Astrid Schrammel
- Department of Pharmacology and Toxicology, University of Graz, Humboldtstraße 46, A-8010, Graz, Austria.
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Wölkart G, Kollau A, Stessel H, Russwurm M, Koesling D, Schrammel A, Schmidt K, Mayer B. Effects of flavoring compounds used in electronic cigarette refill liquids on endothelial and vascular function. PLoS One 2019; 14:e0222152. [PMID: 31498828 PMCID: PMC6733504 DOI: 10.1371/journal.pone.0222152] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 08/18/2019] [Indexed: 12/26/2022] Open
Abstract
Electronic cigarette refill liquids are commercially provided with a wide variety of flavoring agents. A recent study suggested that several common flavors may scavenge nitric oxide (NO) and cause endothelial dysfunction. It was the aim of the present study to investigate the effects of these flavors on NO/cyclic GMP-mediated signaling and vascular relaxation. We tested the flavoring agents for effects on Ca2+-induced cGMP accumulation and NO synthase activation in cultured endothelial cells. NO scavenging was studied with NO-activated soluble guanylate cyclase and as NO release from a NO donor, measured with a NO electrode. Blood vessel function was studied with precontracted rat aortic rings in the absence and presence of acetylcholine or a NO donor. Cinnamaldehyde inhibited Ca2+-stimulated endothelial cGMP accumulation and NO synthase activation at ≥0.3 mM. Cinnamaldehyde and diacetyl inhibited NO-activated soluble guanylate cyclase with IC50 values of 0.56 (0.54–0.58) and 0.29 (0.24–0.36) mM, respectively, and caused moderate NO scavenging at 1 mM that was not mediated by superoxide anions. The other compounds did not scavenge NO at 1 mM. None of the flavorings interfered with acetylcholine-induced vascular relaxation, but they caused relaxation of pre-contracted aortas. The most potent compounds were eugenol and cinnamaldehyde with EC50 values of ~0.5 mM. Since the flavors did not affect endothelium-dependent vascular relaxation, NO scavenging by cinnamaldehyde and diacetyl does not result in impaired blood vessel function. Although not studied in vivo, the low potency of the compounds renders it unlikely that the observed effects are relevant to humans inhaling flavored vapor from electronic cigarettes.
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Affiliation(s)
- Gerald Wölkart
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, Karl-Franzens-Universität Graz, Graz, Austria
| | - Alexander Kollau
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, Karl-Franzens-Universität Graz, Graz, Austria
| | - Heike Stessel
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, Karl-Franzens-Universität Graz, Graz, Austria
| | - Michael Russwurm
- Department of Pharmacology and Toxicology, Ruhr-Universität Bochum, Bochum, Germany
| | - Doris Koesling
- Department of Pharmacology and Toxicology, Ruhr-Universität Bochum, Bochum, Germany
| | - Astrid Schrammel
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, Karl-Franzens-Universität Graz, Graz, Austria
| | - Kurt Schmidt
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, Karl-Franzens-Universität Graz, Graz, Austria
| | - Bernd Mayer
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, Karl-Franzens-Universität Graz, Graz, Austria
- * E-mail:
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Wölkart G, Beretta M, Wenzl MV, Stessel H, Schmidt K, Maeda N, Mayer B, Schrammel A. Tolerance to nitroglycerin through proteasomal down-regulation of aldehyde dehydrogenase-2 in a genetic mouse model of ascorbate deficiency. Br J Pharmacol 2015. [PMID: 23194305 PMCID: PMC3623057 DOI: 10.1111/bph.12081] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background and Purpose L-gulonolactone oxidase-deficient (Gulo(-/-)) mice were used to study the effects of ascorbate deficiency on aortic relaxation by nitroglycerin (GTN) with focus on changes in the expression and activity of vascular aldehyde dehydrogenase-2 (ALDH2), which catalyses GTN bioactivation. Experimental Approach Ascorbate deficiency was induced in Gulo(-/-) mice by ascorbate deprivation for 4 weeks. Some of the animals were concomitantly treated with the proteasome inhibitor bortezomib and effects compared with ascorbate-supplemented Gulo(-/-), untreated or nitrate-tolerant wild-type mice. Aortic relaxation of the experimental groups to GTN, ACh and a NO donor was studied. Changes in mRNA and protein expression of vascular ALDH2 were quantified by qPCR and immunoblotting, respectively, and aortic GTN denitration rates determined. Key Results Like GTN treatment, ascorbate deprivation induced vascular tolerance to GTN that was associated with markedly decreased rates of GTN denitration. Ascorbate deficiency did not affect ALDH2 mRNA levels, but reduced ALDH2 protein expression and the total amount of ubiquitinated proteins to about 40% of wild-type controls. These effects were largely prevented by ascorbate supplementation or treating Gulo(-/-) mice with the 26S proteasome inhibitor bortezomib. Conclusions and Implications Our data indicate that ascorbate deficiency results in vascular tolerance to GTN via proteasomal degradation of ALDH2. The results support the view that impaired ALDH2-catalysed metabolism of GTN contributes significantly to the development of vascular nitrate tolerance and reveal a hitherto unrecognized protective effect of ascorbate in the vasculature.
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Affiliation(s)
- G Wölkart
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, Graz, Austria
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Mussbacher M, Stessel H, Wölkart G, Haemmerle G, Zechner R, Mayer B, Schrammel A. Role of the ubiquitin-proteasome system in cardiac dysfunction of adipose triglyceride lipase-deficient mice. J Mol Cell Cardiol 2014; 77:11-9. [PMID: 25285770 PMCID: PMC4263609 DOI: 10.1016/j.yjmcc.2014.09.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 09/25/2014] [Accepted: 09/26/2014] [Indexed: 12/12/2022]
Abstract
Systemic deletion of the gene encoding for adipose triglyceride lipase (ATGL) in mice leads to severe cardiac dysfunction due to massive accumulation of neutral lipids in cardiomyocytes. Recently, impaired peroxisome proliferator-activated receptor α (PPARα) signaling has been described to substantially contribute to the observed cardiac phenotype. Disturbances of the ubiquitin-proteasome system (UPS) have been implicated in numerous cardiac diseases including cardiomyopathy, ischemic heart disease, and heart failure. The objective of the present study was to investigate the potential role of UPS in cardiac ATGL deficiency. Our results demonstrate prominent accumulation of ubiquitinated proteins in hearts of ATGL-deficient mice, an effect that was abolished upon cardiomyocyte-directed overexpression of ATGL. In parallel, cardiac protein expression of the ubiquitin-activating enzyme E1a, which catalyzes the first step of the ubiquitination cascade, was significantly upregulated in ATGL-deficient hearts. Dysfunction of the UPS was accompanied by activation of NF-κB signaling. Moreover, the endoplasmic reticulum (ER)-resident chaperon protein disulfide isomerase was significantly upregulated in ATGL-deficient hearts. Chronic treatment of ATGL-deficient mice with the PPARα agonist Wy14,643 improved proteasomal function, prevented NF-κB activation and decreased oxidative stress. In summary, our data point to a hitherto unrecognized link between proteasomal function, PPARα signaling and cardiovascular disease.
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Affiliation(s)
- Marion Mussbacher
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria.
| | - Heike Stessel
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria.
| | - Gerald Wölkart
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria.
| | - Guenter Haemmerle
- Department of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria.
| | - Rudolf Zechner
- Department of Molecular Biosciences, University of Graz, Heinrichstrasse 31, A-8010 Graz, Austria.
| | - Bernd Mayer
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria.
| | - Astrid Schrammel
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, A-8010 Graz, Austria.
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Schrammel A, Mussbacher M, Wölkart G, Stessel H, Pail K, Winkler S, Schweiger M, Haemmerle G, Al Zoughbi W, Höfler G, Lametschwandtner A, Zechner R, Mayer B. Endothelial dysfunction in adipose triglyceride lipase deficiency. Biochim Biophys Acta 2014; 1841:906-17. [PMID: 24657704 PMCID: PMC4000266 DOI: 10.1016/j.bbalip.2014.03.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 02/27/2014] [Accepted: 03/13/2014] [Indexed: 12/31/2022]
Abstract
Systemic knockout of adipose triglyceride lipase (ATGL), the pivotal enzyme of triglyceride lipolysis, results in a murine phenotype that is characterized by progredient cardiac steatosis and severe heart failure. Since cardiac and vascular dysfunction have been closely related in numerous studies we investigated endothelium-dependent and -independent vessel function of ATGL knockout mice. Aortic relaxation studies and Langendorff perfusion experiments of isolated hearts showed that ATGL knockout mice suffer from pronounced micro- and macrovascular endothelial dysfunction. Experiments with agonists directly targeting vascular smooth muscle cells revealed the functional integrity of the smooth muscle cell layer. Loss of vascular reactivity was restored ~50% upon treatment of ATGL knockout mice with the PPARα agonist Wy14,643, indicating that this phenomenon is partly a consequence of impaired cardiac contractility. Biochemical analysis revealed that aortic endothelial NO synthase expression and activity were significantly reduced in ATGL deficiency. Enzyme activity was fully restored in ATGL mice treated with the PPARα agonist. Biochemical analysis of perivascular adipose tissue demonstrated that ATGL knockout mice suffer from perivascular inflammatory oxidative stress which occurs independent of cardiac dysfunction and might contribute to vascular defects. Our results reveal a hitherto unrecognized link between disturbed lipid metabolism, obesity and cardiovascular disease.
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Affiliation(s)
- Astrid Schrammel
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
| | - Marion Mussbacher
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
| | - Gerald Wölkart
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
| | - Heike Stessel
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
| | - Karoline Pail
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
| | - Sarah Winkler
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
| | - Martina Schweiger
- Department of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria.
| | - Guenter Haemmerle
- Department of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria.
| | - Wael Al Zoughbi
- Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8010 Graz, Austria.
| | - Gerald Höfler
- Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8010 Graz, Austria.
| | - Alois Lametschwandtner
- Department of Cell Biology and Physiology, Vessel and Muscle Research Unit, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria.
| | - Rudolf Zechner
- Department of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria.
| | - Bernd Mayer
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
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Kolesnik B, Palten K, Schrammel A, Stessel H, Schmidt K, Mayer B, Gorren AC. Efficient nitrosation of glutathione by nitric oxide. Free Radic Biol Med 2013; 63:51-64. [PMID: 23660531 PMCID: PMC3734348 DOI: 10.1016/j.freeradbiomed.2013.04.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 01/24/2013] [Accepted: 04/27/2013] [Indexed: 02/07/2023]
Abstract
Nitrosothiols are increasingly regarded as important participants in a range of physiological processes, yet little is known about their biological generation. Nitrosothiols can be formed from the corresponding thiols by nitric oxide in a reaction that requires the presence of oxygen and is mediated by reactive intermediates (NO₂ or N₂O₃) formed in the course of NO autoxidation. Because the autoxidation of NO is second order in NO, it is extremely slow at submicromolar NO concentrations, casting doubt on its physiological relevance. In this paper we present evidence that at submicromolar NO concentrations the aerobic nitrosation of glutathione does not involve NO autoxidation but a reaction that is first order in NO. We show that this reaction produces nitrosoglutathione efficiently in a reaction that is strongly stimulated by physiological concentrations of Mg(2+). These observations suggest that direct aerobic nitrosation may represent a physiologically relevant pathway of nitrosothiol formation.
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Schrammel A, Mussbacher M, Wölkart G, Stessel H, Hämmerle G, Al Zoughbi W, Höfler G, Lametschwandtner A, Zechner R, Mayer B. Endothelial dysfunction in a mouse model of human neutral lipid storage disease. BMC Pharmacol Toxicol 2013. [PMCID: PMC3765552 DOI: 10.1186/2050-6511-14-s1-p64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Schrammel A, Mussbacher M, Winkler S, Haemmerle G, Stessel H, Wölkart G, Zechner R, Mayer B. Cardiac oxidative stress in a mouse model of neutral lipid storage disease. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1600-8. [PMID: 23867907 PMCID: PMC3795454 DOI: 10.1016/j.bbalip.2013.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/19/2013] [Accepted: 07/08/2013] [Indexed: 12/11/2022]
Abstract
Cardiac oxidative stress has been implicated in the pathogenesis of hypertrophy, cardiomyopathy and heart failure. Systemic deletion of the gene encoding adipose triglyceride lipase (ATGL), the enzyme that catalyzes the rate-limiting step of triglyceride lipolysis, results in a phenotype characterized by severe steatotic cardiac dysfunction. The objective of the present study was to investigate a potential role of oxidative stress in cardiac ATGL deficiency. Hearts of mice with global ATGL knockout were compared to those of mice with cardiomyocyte-restricted overexpression of ATGL and to those of wildtype littermates. Our results demonstrate that oxidative stress, measured as lucigenin chemiluminescence, was increased ~ 6-fold in ATGL-deficient hearts. In parallel, cytosolic NADPH oxidase subunits p67phox and p47phox were upregulated 4–5-fold at the protein level. Moreover, a prominent upregulation of different inflammatory markers (tumor necrosis factor α, monocyte chemotactant protein-1, interleukin 6, and galectin-3) was observed in those hearts. Both the oxidative and inflammatory responses were abolished upon cardiomyocyte-restricted overexpression of ATGL. Investigating the effect of oxidative and inflammatory stress on nitric oxide/cGMP signal transduction we observed a ~ 2.5-fold upregulation of soluble guanylate cyclase activity and a ~ 2-fold increase in cardiac tetrahydrobiopterin levels. Systemic treatment of ATGL-deficient mice with the superoxide dismutase mimetic Mn(III)tetrakis (4-benzoic acid) porphyrin did not ameliorate but rather aggravated cardiac oxidative stress. Our data suggest that oxidative and inflammatory stress seems involved in lipotoxic heart disease. Upregulation of soluble guanylate cyclase and cardiac tetrahydrobiopterin might be regarded as counterregulatory mechanisms in cardiac ATGL deficiency. ATGL(−/−) mice suffer from severe cardiac oxidative stress originating from upregulation of NOX2-dependent NADPH oxidase. Inflammation markers TNFα, MCP-1, IL-6, and Mac-2 are increased in cardiac ATGL deficiency. Activity of sGC and cardiac BH4 levels are elevated in ATGL(−/−) hearts. Systemic treatment of ATGL(−/−) mice with the SOD mimetic MnTBAP did not ameliorate oxidative stress.
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Key Words
- (s)GC
- (soluble) guanylate cyclase
- 2,2-diethyl-1-nitroso-oxyhydrazine
- ATGL
- ATGL(−/−)
- Adipose triglyceride lipase
- BH(2)
- BH(4)
- Cardiac hypertrophy
- DAG
- DEA/NO
- FFA
- GAPDH
- IL-6
- Inflammation
- MCP-1
- Mac-2
- Mn(III)tetrakis (4-benzoic acid) porphyrin chloride
- MnTBAP
- NADPH
- NADPH oxidase
- NO
- NOX
- ONOO(−)
- Oxidative stress
- PBS
- PKC
- PPARα
- SOD
- TG
- TNFα
- VASP
- adipose triglyceride lipase
- adipose triglyceride lipase knockout
- diacylglycerol
- dihydrobiopterin, [2-amino-6-(1,2-dihydroxypropyl)-7,8-dihydro-1H-pteridin-4-one]
- eNOS
- endothelial nitric oxide synthase
- free fatty acid
- galectin-3
- glyceraldehyde-3-phosphate dehydrogenase
- iNOS
- inducible nitric oxide synthase
- interleukin 6
- monocyte chemotactic protein-1
- nNOS
- neuronal nitric oxide synthase
- nicotinamide adenine dinucleotide phosphate
- nitric oxide
- pVASP
- peroxisome proliferator receptor α
- peroxynitrite
- phosphate-buffered saline
- phosphorylated vasodilator-stimulated phosphoprotein
- protein kinase C
- superoxide dismutase
- tetrahydrobiopterin, [(6R)-2-amino-6-[(1R,2S)-1,2-dihydroxypropyl]-5,6,7,8-tetrahydropteridin-4(1H)-one]
- triacylglycerol
- tumor necrosis factor α
- vasodilator-stimulated phosphoprotein
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Affiliation(s)
- Astrid Schrammel
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
- Corresponding author. Tel.: + 43 316 380 5559; fax: + 43 316 380 9890.
| | - Marion Mussbacher
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Sarah Winkler
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Guenter Haemmerle
- Department of Molecular Biosciences, University of Graz, Heinrichstraße 31, 8010 Graz, Austria
| | - Heike Stessel
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Gerald Wölkart
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Rudolf Zechner
- Department of Molecular Biosciences, University of Graz, Heinrichstraße 31, 8010 Graz, Austria
| | - Bernd Mayer
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
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Schrammel A, Wölkart G, Beretta M, Stessel H, Schmidt K, Maeda N, Mayer B. Tolerance to nitroglycerin through proteasomal degradation of aldehyde dehydrogenase-2 in a genetic mouse model of ascorbate deficiency. BMC Pharmacol Toxicol 2012. [PMCID: PMC3506294 DOI: 10.1186/2050-6511-13-s1-a36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Schmidt K, Rehn M, Stessel H, Wölkart G, Mayer B. Evidence against tetrahydrobiopterin depletion of vascular tissue exposed to nitric oxide/superoxide or nitroglycerin. Free Radic Biol Med 2010; 48:145-52. [PMID: 19853656 DOI: 10.1016/j.freeradbiomed.2009.10.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 09/15/2009] [Accepted: 10/16/2009] [Indexed: 11/22/2022]
Abstract
Several cardiovascular disorders, including atherosclerosis and tolerance to the antianginal drug nitroglycerin (GTN), may be associated with the generation of superoxide anions, which react with nitric oxide (NO) to yield peroxynitrite. According to a widely held view, oxidation of tetrahydrobiopterin (BH(4)) by peroxynitrite causes uncoupling of endothelial NO synthase (eNOS), resulting in reduced NO bioavailability and endothelial dysfunction under conditions of oxidative stress. In this study we determined the levels of reduced biopterins and endothelial function in cultured cells exposed to peroxynitrite and GTN as well as in blood vessels isolated from GTN-tolerant guinea pigs and rats. BH(4) was rapidly oxidized by peroxynitrite and 3-morpholino sydnonimine (SIN-1) in buffer, but this was prevented by glutathione and not observed in endothelial cells exposed to SIN-1 or GTN. Prolonged treatment of the cells with 0.1 mM GTN caused slow N(G)-nitro-l-arginine-sensitive formation of reactive oxygen species without affecting eNOS activity. Endothelial function and BH(4)/BH(2) levels were identical in blood vessels of control and GTN-tolerant animals. Our results suggest that peroxynitrite-triggered BH(4) oxidation does not occur in endothelial cells or GTN-exposed blood vessels. GTN seems to trigger minor eNOS uncoupling that is unrelated to BH(4) depletion and without observable consequence on eNOS function.
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Affiliation(s)
- Kurt Schmidt
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, A-8010 Graz, Austria
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Zeller A, Wenzl MV, Beretta M, Stessel H, Russwurm M, Koesling D, Schmidt K, Mayer B. Mechanisms underlying activation of soluble guanylate cyclase by the nitroxyl donor Angeli's salt. Mol Pharmacol 2009; 76:1115-22. [PMID: 19720727 DOI: 10.1124/mol.109.059915] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitroxyl (HNO) may be formed endogenously by uncoupled nitric-oxide (NO) synthases, enzymatic reduction of NO or as product of vascular nitroglycerin bioactivation. The established HNO donor Angeli's salt (trioxodinitrate, AS) causes cGMP-dependent vasodilation through activation of soluble guanylate cyclase (sGC). We investigated the mechanisms underlying this effect using purified sGC and cultured endothelial cells. AS (up to 0.1 mM) had no significant effect on sGC activity in the absence of superoxide dismutase (SOD) or dithiothreitol (DTT). In the presence of SOD, AS caused biphasic sGC activation (apparent EC(50) approximately 10 nM, maximum at 1 microM) that was accompanied by the formation of NO. DTT (2 mM) inhibited the effects of <10 microM AS but led to sGC activation and NO release at 0.1 mM AS even without SOD. AS had no effect on ferric sGC, excluding activation of the oxidized enzyme by HNO. The NO scavenger carboxy-PTIO inhibited endothelial cGMP accumulation induced by AS in the presence but not in the absence of SOD (EC(50) approximately 50 nM and approximately 16 microM, respectively). Carboxy-PTIO (0.1 mM) inhibited the effect of <or=10 microM AS in the presence of SOD but caused NO release from 0.1 mM AS in the absence of SOD. These data indicate that AS activates sGC exclusively via NO, formed either via SOD-catalyzed oxidation of HNO or through a minor AS decomposition pathway that is unmasked in the presence of HNO scavenging thiols.
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Affiliation(s)
- Andreas Zeller
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, Graz, Austria
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Wenzl MV, Wölkart G, Stessel H, Beretta M, Schmidt K, Mayer B. Different effects of ascorbate deprivation and classical vascular nitrate tolerance on aldehyde dehydrogenase-catalysed bioactivation of nitroglycerin. Br J Pharmacol 2009; 156:1248-55. [PMID: 19254277 DOI: 10.1111/j.1476-5381.2009.00126.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Vascular tolerance to nitroglycerin (GTN) may be caused by impaired GTN bioactivation due to inactivation of mitochondrial aldehyde dehydrogenase (ALDH2). As relaxation to GTN is reduced but still sensitive to ALDH2 inhibitors in ascorbate deficiency, we compared the contribution of ALDH2 inactivation to GTN hyposensitivity in ascorbate deficiency and classical in vivo nitrate tolerance. EXPERIMENTAL APPROACH Guinea pigs were fed standard or ascorbate-free diet for 2 weeks. Reversibility was tested by feeding ascorbate-deficient animals standard diet for 1 week. Nitrate tolerance was induced by subcutaneous injection of 50 mg x kg(-1) GTN 4 times daily for 3 days. Ascorbate levels were determined in plasma, blood vessels, heart and liver. GTN-induced relaxation was measured as isometric tension of aortic rings; vascular GTN biotransformation was assayed as formation of 1,2- and 1,3-glyceryl dinitrate (GDN). KEY RESULTS Two weeks of ascorbate deprivation had no effect on relaxation to nitric oxide but reduced the potency of GTN approximately 10-fold in a fully reversible manner. GTN-induced relaxation was similarly reduced in nitrate tolerance but not further attenuated by ALDH inhibitors. Nitrate tolerance reduced ascorbate plasma levels without affecting ascorbate in blood vessels, liver and heart. GTN denitration was significantly diminished in nitrate-tolerant and ascorbate-deficient rings. However, while the approximately 10-fold preferential 1,2-GDN formation, indicative for active ALDH2, had been retained in ascorbate deficiency, selectivity was largely lost in nitrate tolerance. CONCLUSIONS AND IMPLICATIONS These results indicate that nitrate tolerance is associated with ALDH2 inactivation, whereas ascorbate deficiency possibly results in down-regulation of ALDH2 expression.
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Affiliation(s)
- M V Wenzl
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, Graz, Austria
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Mayer B, Kleschyov AL, Stessel H, Russwurm M, Münzel T, Koesling D, Schmidt K. Inactivation of Soluble Guanylate Cyclase by Stoichiometric S-Nitrosation. Mol Pharmacol 2008; 75:886-91. [DOI: 10.1124/mol.108.052142] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Stessel H, Brunner F. Effect of Endothelin Antagonism on Contractility, Intracellular Calcium Regulation and Calcium Regulatory Protein Expression in Right Ventricular Hypertrophy of the Rat. Basic Clin Pharmacol Toxicol 2008. [DOI: 10.1111/j.1742-7843.2004.pto_940107.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
AIMS Nitroglycerin (GTN) acts through release of a nitric oxide (NO)-related activator of soluble guanylate cyclase in vascular smooth muscle. Besides enzymatic GTN bioactivation catalysed by aldehyde dehydrogenase, non-enzymatic reaction of GTN with ascorbate also results in the formation of a bioactive product. Using an established guinea pig model of ascorbate deficiency, we investigated whether endogenous ascorbate contributes to GTN-induced vasodilation. METHODS AND RESULTS Guinea pigs were fed either standard or ascorbate-free diet for 2 or 4 weeks prior to measuring the GTN response of aortic rings and isolated hearts. The effects of ascorbate on GTN metabolism were studied with purified mitochondrial aldehyde dehydrogenase (ALDH2) and isolated mitochondria. Ascorbate deprivation led to severe scorbutic symptoms and loss of body weight, but had no (2 weeks) or only slight (4 weeks) effects on aortic relaxations to a direct NO donor. The EC(50) of GTN was increased from 0.058 +/- 0.018 to 0.46 +/- 0.066 and 5.5 +/- 0.9 microM after 2 and 4 weeks of ascorbate-free diet, respectively. Similarly, coronary vasodilation to GTN was severely impaired in ascorbate deficiency. The potency of GTN was reduced to a similar extent by ALDH inhibitors in control and ascorbate-deficient blood vessels. Up to 10 mM ascorbate had no effect on GTN metabolism catalysed by purified ALDH2 or liver mitochondria isolated from ascorbate-deficient guinea pigs. CONCLUSION Our results indicate that prolonged ascorbate deficiency causes tolerance to GTN without affecting NO/cyclic GMP-mediated vasorelaxation.
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Affiliation(s)
- Gerald Wölkart
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, Universitätsplatz 2, A-8010 Graz, Austria
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Wölkart G, Pang X, Stessel H, Kirchengast M, Brunner F. Chronic endothelin-A receptor antagonism is as protective as angiotensin converting enzyme inhibition against cardiac dysfunction in diabetic rats. Br J Pharmacol 2007; 151:1187-97. [PMID: 17572700 PMCID: PMC2189828 DOI: 10.1038/sj.bjp.0707325] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 04/23/2007] [Accepted: 05/02/2007] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Diabetes mellitus is associated with a specific cardiomyopathy. We compared the cardioprotective effects of an endothelin-A receptor blocker (ET(A)-RB) with those of an angiotensin-converting enzyme inhibitor (ACE-I) in rats with streptozotocin (STZ)-induced diabetes. EXPERIMENTAL APPROACH Diabetic rats were left untreated or received either the ET(A)-RB atrasentan or the ACE-I ramipril (each 3 mg kg(-1) per day) orally for 8 weeks. Isolated isovolumic heart function was studied during normoxia and in response to ischaemia-reperfusion. Cardiac fibrosis, tissue oxidative stress and tissue nitric oxide synthase (NOS) activity were determined. KEY RESULTS Basal left ventricular systolic contractility was lower in diabetic compared to nondiabetic hearts and ET(A)-RB or ACE-I treatment significantly antagonised the decline. Following 15 min of no-flow ischaemia, reperfusion systolic function was depressed and left-ventricular end-diastolic pressure (LVEDP) was elevated in diabetic hearts. ET(A)-RB or ACE-I treatment significantly improved recovery of reperfusion systolic and diastolic function, without differences between groups. Hydroxyproline (an index of tissue fibrosis) and malondialdehyde (a measure of tissue oxidative stress) were elevated at the end of reperfusion in diabetic, compared to nondiabetic hearts. Either treatment reduced hydroxyproline and malondialdehyde to control level. Constitutive NOS activity was similar in nondiabetic and diabetic hearts and unaffected by ET(A)-RB or ACE-I treatment. CONCLUSIONS AND IMPLICATIONS These results suggest that in experimental type 1 diabetes ET(A)-RB is as effective as an ACE-I in ameliorating myocardial functions during normoxia and ischaemia-reperfusion. Combining the two treatments neither afforded additive effects, nor diminished any protection effect seen with either drug.
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Affiliation(s)
- G Wölkart
- Department of Pharmacology and Toxicology, University of Graz Graz, Austria
| | - X Pang
- Department of Pharmacology and Toxicology, University of Graz Graz, Austria
| | - H Stessel
- Department of Pharmacology and Toxicology, University of Graz Graz, Austria
| | - M Kirchengast
- PRA International Mannheim, Germany
- Faculty of Clinical Medicine, Department of Pharmacology and Toxicology, Mannheim Ruprecht-Karls-University Heidelberg Mannheim, Germany
| | - F Brunner
- Department of Pharmacology and Toxicology, University of Graz Graz, Austria
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Pozo-Navas B, Stessel H, Wölkart G, Brunner F. Role of myocardial nitric oxide in diabetic ischemia-reperfusion dysfunction: studies in mice with myocyte-specific overexpression of endothelial nitric-oxide synthase. J Pharmacol Exp Ther 2006; 319:729-38. [PMID: 16857730 DOI: 10.1124/jpet.106.107854] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the role of nitric oxide (NO) in myocardial ischemia-reperfusion injury of diabetic mice with myocyte-specific overexpression of endothelial NO synthase (NOS). Four weeks after diabetes induction with streptozotocin (blood glucose approximately 29 mM), isolated isovolumic heart function and cellular NO metabolites in response to brief normothermic ischemia-reperfusion were determined. Under normoxic conditions transgenic (TG) hearts from nondiabetic and diabetic animals generated less left-ventricular developed pressure compared with wild-type (WT) control hearts, and this abnormality was unaffected by NOS inhibition. During ischemia, the rise in end-diastolic pressure was less in the TG than WT group of nondiabetic hearts, whereas the transgene had no effect in the diabetic group. Similarly, the transgene also improved reperfusion systolic and diastolic function in nondiabetic but not in diabetic hearts. NOS inhibition worsened reperfusion function in diabetic hearts. Postischemic nitrite and cGMP formation were higher in nondiabetic TG than WT hearts, but in diabetic hearts cGMP was no longer elevated. The formation of reactive oxygen species (superoxide and peroxynitrite) during early reperfusion, measured by electron spin resonance spectroscopy, was similar in nondiabetic WT and TG hearts, but it was significantly higher in diabetic TG hearts. Stimulating endogenous NO production with 10 microM bradykinin more strongly reduced myocardial O(2) consumption in diabetic TG than diabetic WT hearts perfused in normoxia, whereas there was no difference after ischemia-reperfusion. Thus, providing additional endogenous NO is sufficient to protect nondiabetic hearts against ischemia-induced injury, but for a similar protection in diabetic hearts, effective scavenging of reactive oxygen species is also important.
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Affiliation(s)
- Beatriz Pozo-Navas
- Department of Pharmacology and Toxicology, Universität Graz, Universitätsplatz 2, A-8010 Graz, Austria
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Wölkart G, Stessel H, Saad Z, Kirchengast M, Brunner F. Cardioprotective effects of atrasentan, an endothelin-A receptor antagonist, but not of nitric oxide in diabetic mice with myocyte-specific overexpression of endothelial nitric oxide synthase. Br J Pharmacol 2006; 148:671-81. [PMID: 16702986 PMCID: PMC1751871 DOI: 10.1038/sj.bjp.0706772] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. We investigated the roles of nitric oxide (NO) and endothelin-1 (ET-1) in organ dysfunction in diabetic mice with normal genotype (wild-type, WT) or myocyte-specific overexpression of endothelial NO synthase (eNOS) (transgenic, TG) after chronic oral treatment with the endothelin-A (ETA) receptor antagonist atrasentan. 2. Mice were rendered diabetic by injection of 200 mg kg-1 streptozotocin (STZ). Experimental groups were: untreated WT diabetic (n=9), untreated TG diabetic (n=9), atrasentan-treated WT diabetic (n=9), atrasentan-treated TG diabetic (n=8) and the four corresponding nondiabetic groups (n=5). Atrasentan was administered orally via drinking water at 3 mg kg-1 per day over 28 days. All diabetic mice developed similar hyperglycaemia (27-30 mmol l-1). 3. Atrasentan treatment significantly improved left ventricular systolic and diastolic function in response to exogenous norepinephrine, but there were no differences between genotypes. 4. Atrasentan antagonized the diabetic impairments in endothelium-dependent coronary relaxation and thromboxane-receptor mediated aortic constriction. Further, it improved cardiac and renal oxidant status as evident from reduced tissue malondialdehyde levels. 5. Atrasentan reduced diabetic urine flow, proteinuria and plasma creatinine levels, but creatinine clearance was not significantly altered. 6. These results suggest that in experimental type 1 diabetes, blocking ETA receptors ameliorates myocardial, coronary and renal function and improves tissue oxidant status, whereas raising myocardial NO levels has neither beneficial nor deleterious effects on diabetic cardiomyopathy in this transgenic model.
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Affiliation(s)
- Gerald Wölkart
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, Graz 8010, Austria
| | - Heike Stessel
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, Graz 8010, Austria
| | - Zora Saad
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, Graz 8010, Austria
| | - Michael Kirchengast
- PRA International, Dynamostrasse 13-15, Mannheim D-681161 Germany
- Institute of Pharmacology and Toxicology, Faculty of Clinical Medicine, Mannheim Ruprecht-Karls-University Heidelberg, Mannheim, Germany
| | - Friedrich Brunner
- Department of Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, Graz 8010, Austria
- Author for correspondence:
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Wölkart G, Stessel H, Brunner F. In vivo administration of d-arginine: effects on blood pressure and vascular function in angiotensin II-induced hypertensive rats. Atherosclerosis 2004; 176:219-25. [PMID: 15380443 DOI: 10.1016/j.atherosclerosis.2004.05.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2004] [Revised: 05/14/2004] [Accepted: 05/28/2004] [Indexed: 11/20/2022]
Abstract
OBJECTIVE We tested the hypothesis that D-arginine (D-Arg), which is not a substrate for nitric oxide synthase but scavenges reactive oxygen in vitro, is protective in vivo. METHODS Rats were made hypertensive by administering angiotensin II (Ang II) (0.7mg kg(-1) per day) for 7 days (Ang II group). Two other groups additionally received either 3 mmol D-Arg (Ang II + D-Arg group) or vitamin C (1g) (Ang II + Vit C group) per day. Sham-operated animals served as controls (n = 6-9). Systolic blood pressure was monitored daily and cardiovascular function determined ex vivo at 7 days. RESULTS Ang II raised systolic blood pressure to 184mmHg, the increase was slightly attenuated by D-Arg treatment (-17mmHg; P < 0.05 versus Ang II alone) and prevented by Vit C. Acetylcholine-induced coronary relaxation was impaired in the Ang II group (P < 0.05 versus sham), the impairment was no different in the Ang II + D-Arg group, but prevented by Vit C. Likewise, Vit C but not D-Arg ameliorated reperfusion endothelium-dependent relaxation. However, in aortic rings D-Arg slightly improved acetylcholine relaxation (P < 0.05). Oxidative stress load estimated in plasma with thiobarbituric acid reactive substance was higher in the Ang II than the sham group, Vit C abolished the increase, but D-Arg was without effect. CONCLUSION D-Arg is weakly antihypertensive in vivo and ameliorates aortic, but not coronary endothelium-dependent relaxation ex vivo. Because D-Arg had no effect on plasma oxidant status, this protection appears to be independent of reactive oxygen scavenging activity.
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Affiliation(s)
- Gerald Wölkart
- Institut für Pharmakologie und Toxikologie, Universität Graz, Universitätsplatz 2, A-8010 Graz, Austria
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Stessel H, Brunner F. Effect of endothelin antagonism on contractility, intracellular calcium regulation and calcium regulatory protein expression in right ventricular hypertrophy of the rat. Basic Clin Pharmacol Toxicol 2004; 94:37-45. [PMID: 14725613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
We have documented the effects of long-term endothelin receptor antagonism on intracellular Ca2+ regulation and Ca2+ regulatory protein expression in rat hearts with right ventricular hypertrophy without signs of heart failure. Rats were given either a single injection of monocrotaline (50 mg/kg, n=9) resulting in pulmonary hypertension-induced myocardial hypertrophy, or monocrotaline followed by daily administration of the endothelin subtype-A receptor antagonist 2-benzo(1,3)dioxol-5-yl-3-benzyl-4-(4-methoxy-phenyl-)-4-oxobut-2-enoate-Na (PD 155080, 50 mg/kg) over 9 weeks (n=8). Hearts from saline-injected rats served as controls (n=9). Monocrotaline-treated animals developed marked right-sided hypertrophy without fibrosis as evident from hydroxyproline measurements, systolic contractility was increased, fully compensating for the increased afterload, but diastolic function was impaired as evident from protracted relaxation and slowed diastolic intracellular Ca2+ handling (measured by aequorin bioluminescence). In hypertrophic hearts, quantitative immunoblotting analyses showed increased levels both of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) and phosphorylated phospholamban, along with decreased levels of total phospholamban, which is in line with strengthened right ventricular systolic function. PD 155080 reversed abnormalities in Ca2+ handling, although SERCA and phospholamban protein levels were not altered (P=not significant versus monocrotaline group). Thus, endothelin-A receptor antagonism attenuates right ventricular remodeling and improves myocardial Ca2+ handling, but has no discernable effect on elevated expression of SERCA and phospholamban observed in hypertrophic hearts. These data indicate that the hypotensive action of PD 155080 is independent of its effects, if any, on SERCA and its regulation.
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Affiliation(s)
- Heike Stessel
- Institute of Pharmacology and Toxicology, Karl-Franzens-University of Graz, Universitätsplatz 2, A-8010 Graz, Austria
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Stessel H, Brunner F. Effect of Endothelin Antagonism on Contractility, Intracellular Calcium Regulation and Calcium Regulatory Protein Expression in Right Ventricular Hypertrophy of the Rat. ACTA ACUST UNITED AC 2004. [DOI: 10.1111/j.1742-7843.2004.pto940107.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
BACKGROUND Human primary varicosity is associated with 'weakness' of the vein wall. We investigated whether the reduced responsiveness of varicose veins to physiological vasoconstrictors might result from impaired Ca2+ mobilization in venous smooth muscle. MATERIALS AND METHODS The hypothesis was tested in cells derived from phenotypically different vein segments that were obtained from the inguinal saphenous vein (tissue with incompetent valves), the distal portion of the long saphenous vein just above the medial ankle (clinically healthy tissue), and from a tributary to the long saphenous vein just below the knee (incompetent and overtly varicose tissue). Saphenous vein from patients undergoing cardiac surgery served as control. Cytosolic free Ca2+ levels ([Ca2+]i) were determined with the fura-2 method in cultured medial smooth muscle cells of third to sixth passage (21-23 measurements per tissue derived from five controls and seven patients). RESULTS Angiotensin II (10 nmol L-1 to 10 mumol L-1) induced a significantly (P < 0.05) smaller rise in [Ca(2+)1i response in cells derived from incompetent or varicose segments (approximatley 70 nmol L-1) than in cells derived from clinically healthy vein (approximately 130 nmol L-1) or controls (approximately 170 nmol L-1). Likewise, the effect of endothelin-1 (100 nmol L-1) on [Ca2+]i was considerably less in cells derived from segments with incompetent valves or from varicose vessel segments than in cells derived from control patients (P < 0.05). In organ baths, endothelium-denuded strips of varicose vessels contracted significantly less in response to these agonists than clinically healthy segments from the same patient. CONCLUSIONS The reduced contractility of diseased human varicose veins in response to angiotensin II and endothelin-1 involves impaired Ca2+ mobilization.
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Affiliation(s)
- S Schuller-Petrovic
- Department of Dermatology, University Clinic, University of Graz, Graz, Austria
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Abstract
The role of nitric oxide (NO) and guanosine 3',5'-cyclic monophosphate (cyclic GMP) in cellular regulation of endothelin-1 (ET-1) secretion was investigated in cultured porcine aortic endothelial cells. NO synthase was inhibited with NG-nitro-L-arginine (L-NNA) and guanylyl cyclase with the novel selective inhibitor, ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) (3 microM). Basal and phorbol ester (PMA)-stimulated ET-1 secretion were unaffected by ODQ, but stimulated secretion was increased by L-NNA. In the presence of the NO donors, spermine/NO, S-nitroso-glutathione (GSNO), and nitroprusside (NP) ET-1 secretion was reduced, but ODQ had no effect on this inhibition, although it effectively inhibited cyclic GMP production. NO release from donors, measured with a sensitive NO electrode, was greatest for spermine/NO, intermediate for GSNO, minimal for NP and paralleled inhibition of ET-1 secretion. The data suggest that in cultured endothelial cells, curtailment of ET-1 secretion is mediated by NO and independent of cyclic GMP.
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Affiliation(s)
- F Brunner
- Institut für Pharmakologie und Toxikologie, Universität Graz, Austria
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Brunner F, Stessel H, Watzinger N, Löffler BM, Opie LH. Binding of endothelin to plasma proteins and tissue receptors: effects on endothelin determination, vasoactivity, and tissue kinetics. FEBS Lett 1995; 373:97-101. [PMID: 7589443 DOI: 10.1016/0014-5793(95)01017-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In vitro binding of (3-[125I]Tyr)-endothelin-1 ([125I]ET-1) and (3-[125I]Tyr)-big ET-1(1-38) ([125I]big ET-1) to plasma proteins of healthy humans, cardiac patients and normotensive and hypertensive rats was investigated by equilibrium dialysis. Binding of both tracers was similar in plasma from healthy humans, patients with congestive heart failure, and following myocardial infarction (approximately 60%), and marginally higher in rat plasmas (approximately 70%). Binding of [125I]ET-1 to human plasma could be explained by binding to human serum albumin. Endogenous plasma ET-1 levels were approximately 9 pg/ml in healthy humans, and approximately 12-16 pg/ml in cardiac patients; big ET-1 concentrations were approximately two- to threefold higher. ET-1 bound to plasma protein was partly lost in column extraction. In rat isolated perfused hearts, the coronary dilator and constrictor potency of exogenous free and albumin-bound ET-1 was similar, whereas the kinetics of endogenous ET-1 was impeded by tight binding to ET receptors. The data indicate that binding of ET-1 to plasma proteins is without effect on peptide vasoactivity, but binding to tissue receptors greatly impedes its tissue kinetics.
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Affiliation(s)
- F Brunner
- Institut für Pharmakologie und Toxikologie, Universität Graz, Austria
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Brunner F, Stessel H, Graier WF. The effects of intracellular Ca2+ concentration and hypoxia on basal endothelin-1 secretion by cultured porcine aortic endothelial cells. Agents Actions Suppl 1995; 45:269-73. [PMID: 7717188 DOI: 10.1007/978-3-0348-7346-8_36] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
When the intracellular free Ca2+ concentration ([Ca2+]i) of porcine aortic endothelial cells incubated in normoxic or hypoxic atmosphere was varied more than tenfold, basal endothelin-1 (ET-1) secretion was maximal at control conditions ([Ca2+]i = 190 nM) and reduced at lower and higher [Ca2+]i. High [Ca2+]i reduced ET-1 synthesis only in part via activation of the NO/cGMP system. Our results provide evidence that basal ET-1 secretion is regulated by [Ca2+]i, and that Ca2+ plays a similar role in hypoxic and normoxic signal transduction.
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Affiliation(s)
- F Brunner
- Institut für Pharmakologie und Toxikologie, Karl-Franzens-Universität Graz, Austria
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Abstract
The role of intracellular free Ca2+ concentration ([Ca2+]i) in cellular regulation of endothelin-1 (ET-1) secretion was investigated in cultured porcine aortic endothelial cells of first passage. Intracellular Ca2+ concentrations were adjusted between 50 nM and 1 microM using EGTA and thapsigargin, respectively. ET-1 secretion was maximal at [Ca2+]i of 190-470 nM, and reduced at low (50 and 110 nM) and high (> 470 nM) [Ca2+]i. The Ca2+ ionophores A23187 and ionomycin (each 1 microM), both of which raise [Ca2+]i above 1 microM, also potently inhibited ET-1 secretion under basal and stimulated conditions. The A23187-induced reduction in ET-1 secretion was not affected by NG-nitro-L-arginine (0.1 mM). Our results provide evidence that basal ET-1 secretion is regulated by Ca2+ and that Ca2+ ionophores reduce ET-1 secretion due to the inhibitory effect of high [Ca2+]i.
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Affiliation(s)
- F Brunner
- Institut für Pharmakologie und Toxikologie, Karl-Franzens-Universität Graz, Austria
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