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Mandel ER, Dunford EC, Abdifarkosh G, Turnbull PC, Perry CGR, Riddell MC, Haas TL. The superoxide dismutase mimetic tempol does not alleviate glucocorticoid-mediated rarefaction of rat skeletal muscle capillaries. Physiol Rep 2018; 5:e13243. [PMID: 28533261 PMCID: PMC5449555 DOI: 10.14814/phy2.13243] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/13/2017] [Accepted: 03/16/2017] [Indexed: 12/17/2022] Open
Abstract
Sustained elevations in circulating glucocorticoids elicit reductions in skeletal muscle microvascular content, but little is known of the underlying mechanisms. We hypothesized that glucocorticoid‐induced oxidative stress contributes to this phenomenon. In rats that were implanted with corticosterone (CORT) or control pellets, CORT caused a significant decrease in muscle glutathione levels and a corresponding increase in protein carbonylation, an irreversible oxidative modification of proteins. Decreased endothelial nitric oxide synthase and increased endothelin‐1 mRNA levels were detected after 9 days of CORT, and blood flow to glycolytic muscles was diminished. Control and CORT rats were treated concurrently with drinking water containing the superoxide dismutase mimetic tempol (172 mg/L) or the α‐1 adrenergic receptor antagonist prazosin (50 mg/L) for 6 or 16 days. Both tempol and prazosin alleviated skeletal muscle protein carbonylation. Tempol failed to prevent CORT‐mediated capillary rarefaction and was ineffective in restoring skeletal muscle blood flow. In contrast, prazosin blocked capillary rarefaction and restored skeletal muscle blood flow to control levels. The failure of tempol to prevent CORT‐induced skeletal muscle microvascular rarefaction does not support a dominant role of superoxide‐induced oxidative stress in this process. Although a decrease in protein carbonylation was observed with prazosin treatment, our data suggest that the maintenance of skeletal muscle microvascular content is related more closely with counteracting the CORT‐mediated influence on skeletal muscle vascular tone.
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Affiliation(s)
- Erin R Mandel
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Emily C Dunford
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Ghoncheh Abdifarkosh
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Patrick C Turnbull
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Christopher G R Perry
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Michael C Riddell
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Tara L Haas
- School of Kinesiology and Health Science and the Muscle Health Research Centre, York University, Toronto, Ontario, Canada
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Cazzaniga A, Maier JAM, Castiglioni S. Prednisolone inhibits SaOS2 osteosarcoma cell proliferation by activating inducible nitric oxide synthase. World J Transl Med 2016; 5:53-58. [DOI: 10.5528/wjtm.v5.i1.53] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/14/2015] [Accepted: 01/31/2016] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of prednisolone, a synthetic glucocorticoid used in inflammatory diseases, on the growth of cultured osteosarcoma cells.
METHODS: Two osteosarcoma cell lines with different degree of differentiation were used. SaOS2 show a rather mature phenotype, while U2OS are negative for almost all osteoblastic markers. The cells were exposed to different concentrations of prednisolone (1-9 μmol/L) with or without antioxidants or the inhibitor of inducible nitric oxide synthase (iNOS) l-N6-(iminoethyl)-lysine-HCl (L-NIL). Cell growth was assessed by counting viable cells. The production of nitric oxide (NO) was measured in the conditioned media by the Griess method. The production of reactive oxygen species was quantified using 2’-7’-dichlorofluorescein diacetate. Western blot with specific antibodies against NOSs was performed on cell extracts.
RESULTS: Prednisolone inhibited SaOS2 cell growth in a dose dependent manner. No significant effects were observed in U2OS. The inhibition of SaOS2 growth is not due to oxidative stress, because antioxidants do not rescue cell proliferation. Since high concentrations of NO inhibit bone formation, we also measured NO and found it induced in SaOS2, but not in U2OS, exposed to prednisolone, because of the upregulation of iNOS as detected by western blot. Therefore, we treated SaOS2 with prednisolone in the presence or in the absence of L-NIL. L-NIL prevented NO release induced by prednisolone at all the concentrations apart from 9 μmol/L. At the same concentrations, we found that L-NIL rescued SaOS2 growth after exposure to prednisolone. In U2OS cells, prednisolone did not induce NO production nor affected cell growth. All together, these data indicate that a link exists between increased amounts of NO and growth inhibition in response to prednisolone in SaOS2.
CONCLUSION: Prednisolone inhibited SaOS2 proliferation by increasing the release of NO through the upregulation of iNOS, while no effect was exerted on U2OS.
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Mata-Greenwood E, Jackson PN, Pearce WJ, Zhang L. Endothelial glucocorticoid receptor promoter methylation according to dexamethasone sensitivity. J Mol Endocrinol 2015; 55:133-46. [PMID: 26242202 PMCID: PMC5113289 DOI: 10.1530/jme-15-0124] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/04/2015] [Indexed: 12/22/2022]
Abstract
We have previously shown that in vitro sensitivity to dexamethasone (DEX) stimulation in human endothelial cells is positively regulated by the glucocorticoid receptor (NR3C1, GR). The present study determined the role of differential GR transcriptional regulation in glucocorticoid sensitivity. We studied 25 human umbilical vein endothelial cells (HUVECs) that had been previously characterized as DEX-sensitive (n=15), or resistant (n=10). Real-time PCR analysis of GR 5'UTR mRNA isoforms showed that all HUVECs expressed isoforms 1B, 1C, 1D, 1F, and 1H, and isoforms 1B and 1C were predominantly expressed. DEX-resistant cells expressed higher basal levels of the 5'UTR mRNA isoforms 1C and 1D, but lower levels of the 5'UTR mRNA isoform 1F than DEX-sensitive cells. DEX treatment significantly decreased GRα and GR-1C mRNA isoform expression in DEX-resistant cells only. Reporter luciferase assays indicated that differential GR mRNA isoform expression was not due to differential promoter usage between DEX-sensitive and DEX-resistant cells. Analysis of promoter methylation, however, showed that DEX-sensitive cells have higher methylation levels of promoter 1D and lower methylation levels of promoter 1F than DEX-resistant cells. Treatment with 5-aza-2-deoxycytidine abolished the differential 5'UTR mRNA isoform expression between DEX-sensitive and DEX-resistant cells. Finally, both GRα overexpression and 5-aza-2-deoxycytidine treatment eliminated the differences between sensitivity groups to DEX-mediated downregulation of endothelial nitric oxide synthase (NOS3), and upregulation of plasminogen activator inhibitor 1 (SERPINE1). In sum, human endothelial GR 5'UTR mRNA expression is regulated by promoter methylation with DEX-sensitive and DEX-resistant cells having different GR promoter methylation patterns.
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Affiliation(s)
- Eugenia Mata-Greenwood
- Divisions of Pharmacology and Physiology Department of Basic Sciences, School of Medicine, Center for Perinatal Biology, Medical Center, Loma Linda University, Room A572, 11234 Anderson Street, Loma Linda, CA 92350, USA
| | - P Naomi Jackson
- Divisions of Pharmacology and Physiology Department of Basic Sciences, School of Medicine, Center for Perinatal Biology, Medical Center, Loma Linda University, Room A572, 11234 Anderson Street, Loma Linda, CA 92350, USA
| | - William J Pearce
- Divisions of Pharmacology and Physiology Department of Basic Sciences, School of Medicine, Center for Perinatal Biology, Medical Center, Loma Linda University, Room A572, 11234 Anderson Street, Loma Linda, CA 92350, USA
| | - Lubo Zhang
- Divisions of Pharmacology and Physiology Department of Basic Sciences, School of Medicine, Center for Perinatal Biology, Medical Center, Loma Linda University, Room A572, 11234 Anderson Street, Loma Linda, CA 92350, USA
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Mata-Greenwood E, Stewart JM, Steinhorn RH, Pearce WJ. Role of BCL2-associated athanogene 1 in differential sensitivity of human endothelial cells to glucocorticoids. Arterioscler Thromb Vasc Biol 2013; 33:1046-55. [PMID: 23493285 DOI: 10.1161/atvbaha.113.301247] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Chronic therapy with synthetic glucocorticoids has been associated with cardiovascular side effects, although differential interindividual susceptibility to glucocorticoids has been observed. The objective of this study was to identify the molecular mechanisms leading to differential glucocorticoid responses in endothelial cells. APPROACH AND RESULTS We tested the sensitivity of 42 human umbilical vein endothelial cells (HUVECs) to dexamethasone as determined by changes in gene expression, promoter transactivation, and procoagulant activity. We identified that 16 HUVECs were sensitive in every test, 14 HUVECs were sensitive in at least 1 test and 12 HUVECs were resistant in every test to dexamethasone. Nuclear translocation assays revealed that Dex-sensitive HUVECs have higher basal and Dex-stimulated levels of nuclear glucocorticoid receptor compared with Dex-resistant HUVECs. Cycloheximide assays revealed that Dex-resistant HUVECs have significantly shorter glucocorticoid receptor protein half-lives than Dex-sensitive HUVECs. Dex-resistant HUVECs have a stronger interaction of glucocorticoid receptor with the proteasomal recruiting protein, BCL2-associated athanogene 1 (BAG1), as shown by immunoprecipitation assays. Silencing BAG1 expression increased Dex-sensitivity in resistant HUVECs, whereas BAG1 overexpression decreased Dex-sensitivity in sensitive HUVECs. Finally, Dex-resistant HUVECs presented higher BAG1 expression than Dex-sensitive HUVECs. CONCLUSIONS In vitro endothelial sensitivity to Dex varies within individuals and is inversely proportional to BAG1 protein expression and glucocorticoid receptor protein turnover.
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Affiliation(s)
- Eugenia Mata-Greenwood
- Department of Basic Sciences, Center for Perinatal Biology, Medical Center, Room A572, Loma Linda University, 11234 Anderson St, Loma Linda, CA 92350, USA.
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Goettsch C, Rauner M, Hamann C, Sinningen K, Hempel U, Bornstein SR, Hofbauer LC. Nuclear factor of activated T cells mediates oxidised LDL-induced calcification of vascular smooth muscle cells. Diabetologia 2011; 54:2690-701. [PMID: 21701818 DOI: 10.1007/s00125-011-2219-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 05/23/2011] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS Vascular calcification is a prominent feature of both atherosclerosis and diabetes, and is clinically associated with osteoporosis. The expression of bone-regulatory factors and the impact of oxidative stress in aortic calcification are well-documented. Recently, nuclear factor of activated T cells (NFAT) cytoplasmic, calcineurin-dependent 1 (NFATc1) was identified in calcified aortic valves and has been implicated in vascular calcification. Therefore, we assessed the mechanisms of osteogenic transdifferentiation of vascular smooth muscle cells induced by oxidised LDL (oxLDL) and evaluated the role of NFAT in this process. METHODS Human coronary artery smooth muscle cells (HCASMCs) were cultured for 21 days in medium supplemented with oxLDL. NFAT was inhibited using the NFAT inhibitor VIVIT, or by knockdown with small interfering RNA (siRNA). Osteogenic transdifferentiation was assessed by gene expression, matrix mineralisation and alkaline phosphatase activity. RESULTS Exposure to oxLDL caused the transformation of HCASMCs towards an osteoblast-like phenotype based on increased mineral matrix formation and RUNX2 expression. NFATc1 blockade completely prevented oxLDL-induced osteogenic transformation of HCASMCs as well as oxLDL-induced stimulation of osteoblast differentiation. In contrast, matrix mineralisation induced by osteogenic medium was independent of the NFAT pathway. Of note, oxLDL-conditioned medium from HCASMCs transferred to bone cells promoted osteoblast mineralisation. Consistent with these in vitro findings, diabetic rats with a twofold increase in oxidised lipid levels displayed higher aortic calcium concentrations and increased expression of osteogenic markers and production of NFATc1. CONCLUSIONS/INTERPRETATION Our results identify the NFAT signalling pathway as a novel regulator of oxLDL-induced transdifferentiation of vascular smooth muscle cells towards an osteoblast-like phenotype.
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Affiliation(s)
- C Goettsch
- Division of Endocrinology, Diabetes and Metabolic Bone Diseases, Department of Medicine III, Technical University Medical Center, Fetscherstraße 74, 01307 Dresden, Germany
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Gielis JF, Lin JY, Wingler K, Van Schil PEY, Schmidt HH, Moens AL. Pathogenetic role of eNOS uncoupling in cardiopulmonary disorders. Free Radic Biol Med 2011; 50:765-76. [PMID: 21172428 DOI: 10.1016/j.freeradbiomed.2010.12.018] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2010] [Revised: 11/14/2010] [Accepted: 12/10/2010] [Indexed: 12/23/2022]
Abstract
The homodimeric flavohemeprotein endothelial nitric oxide synthase (eNOS) oxidizes l-arginine to l-citrulline and nitric oxide (NO), which acutely vasodilates blood vessels and inhibits platelet aggregation. Chronically, eNOS has a major role in the regulation of blood pressure and prevention of atherosclerosis by decreasing leukocyte adhesion and smooth muscle proliferation. However, a disturbed vascular redox balance results in eNOS damage and uncoupling of oxygen activation from l-arginine conversion. Uncoupled eNOS monomerizes and generates reactive oxygen species (ROS) rather than NO. Indeed, eNOS uncoupling has been suggested as one of the main pathomechanisms in a broad range of cardiovascular and pulmonary disorders such as atherosclerosis, ventricular remodeling, and pulmonary hypertension. Therefore, modulating uncoupled eNOS, in particular eNOS-dependent ROS generation, is an attractive therapeutic approach to preventing and/or treating cardiopulmonary disorders, including protective effects during cardiothoracic surgery. This review provides a comprehensive overview of the pathogenetic role of uncoupled eNOS in both cardiovascular and pulmonary disorders. In addition, the related therapeutic possibilities such as supplementation with the eNOS substrate l-arginine, volatile NO, and direct NO donors as well as eNOS modulators such as the eNOS cofactor tetrahydrobiopterin and folic acid are discussed in detail.
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Affiliation(s)
- Jan F Gielis
- Department of Vascular and Thoracic Surgery, University of Antwerp, Antwerp, Belgium
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Jeremy JY, Jones RA, Koupparis AJ, Hotston M, Persad R, Angelini GD, Shukla N. Reactive oxygen species and erectile dysfunction: possible role of NADPH oxidase. Int J Impot Res 2006; 19:265-80. [PMID: 17053777 DOI: 10.1038/sj.ijir.3901523] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Erectile dysfunction (ED) is a widespread condition, the incidence of which is increasing globally. ED is also indicative of underlying vasculopathy and represents a predictor of more serious cardiovascular disorders. Understanding the aetiology of ED may therefore provide invaluable pointers to the pathobiology of other cardiovascular diseases (CVDs) and syndromes. It follows, too, that therapeutic interventions that are successful in treating ED may, ipso facto, be effective in treating the early stages of conditions that include atherosclerosis, angina, plaque rupture and diabetic angiopathy. One common pathological denominator in both CVD and ED is oxidative stress, that is, the overproduction of reactive oxygen species (ROS), in particular, superoxide (O(2)(*-)) and hydrogen peroxide (H(2)O(2)). In this review, therefore, we consider the aetiology and pathobiology of O(2)(*-) in promoting ED and focus on NADPH oxidase as an inducible source of O(2)(*-) and H(2)O(2). Therapeutic strategies aimed at reducing oxidative stress to improve erectile function are also discussed.
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Affiliation(s)
- J Y Jeremy
- Department of Cardiac Surgery, Bristol Heart Institute, Bristol Royal Infirmary, The University of Bristol, Bristol, UK.
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Muzaffar S, Shukla N, Jeremy JY. Nicotinamide adenine dinucleotide phosphate oxidase: a promiscuous therapeutic target for cardiovascular drugs? Trends Cardiovasc Med 2006; 15:278-82. [PMID: 16297764 DOI: 10.1016/j.tcm.2005.09.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Revised: 08/14/2005] [Accepted: 09/01/2005] [Indexed: 02/08/2023]
Abstract
The increased expression and activity of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex has emerged as a major common factor in the etiology of all forms of cardiovascular diseases since the upregulation of intravascular NADPH oxidase results in the formation of superoxide (O(2)(-)), which in turn promotes vasculopathy. An ever-increasing number of drugs commonly used in cardiovascular medicine have been shown to influence NADPH oxidase expression and activity. These include nitric oxide donors, nitroaspirin, eicosanoids, phosphodiesterase inhibitors, corticosteroids, antioxidants, and specific inhibitors. The objective of this review is to discuss these drugs in relation to the mechanisms underlying their effects on NADPH oxidase activity and the expression and therapeutic implications of these effects.
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Affiliation(s)
- Saima Muzaffar
- Department of Cardiac Surgery, Bristol Heart Institute, Bristol Royal Infirmary, University of Bristol, BS2 8HW Bristol, UK
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Jeremy JY, Muzaffar S, Koupparis AJ, Angelini GD, Persad R, Shukla N. Sexual dysfunction and cardiac risk (the second Princeton Concensus Conference). Am J Cardiol 2005; 96:1754-5. [PMID: 16360373 DOI: 10.1016/j.amjcard.2005.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Accepted: 09/02/2005] [Indexed: 11/15/2022]
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