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Gomez-Gutierrez P, Perez JJ. Discovery of a Bradykinin B2 Partial Agonist Profile of Raloxifene in a Drug Repurposing Campaign. Int J Mol Sci 2020; 22:E257. [PMID: 33383825 PMCID: PMC7796052 DOI: 10.3390/ijms22010257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/14/2020] [Accepted: 12/28/2020] [Indexed: 12/15/2022] Open
Abstract
Covid-19 urges a deeper understanding of the underlying molecular mechanisms involved in illness progression to provide a prompt therapeutical response with an adequate use of available drugs, including drug repurposing. Recently, it was suggested that a dysregulated bradykinin signaling can trigger the cytokine storm observed in patients with severe Covid-19. In the scope of a drug repurposing campaign undertaken to identify bradykinin antagonists, raloxifene was identified as prospective compound in a virtual screening process. The pharmacodynamics profile of raloxifene towards bradykinin receptors is reported in the present work, showing a weak selective partial agonist profile at the B2 receptor. In view of this new profile, its possible use as a therapeutical agent for the treatment of severe Covid-19 is discussed.
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Affiliation(s)
| | - Juan J. Perez
- Department of Chemical Engineering, Universitat Politecnica de Catalunya, ETSEIB, Av. Diagonal, 647, 08028 Barcelona, Spain;
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2
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Vanhoutte PM, Shimokawa H, Feletou M, Tang EHC. Endothelial dysfunction and vascular disease - a 30th anniversary update. Acta Physiol (Oxf) 2017; 219:22-96. [PMID: 26706498 DOI: 10.1111/apha.12646] [Citation(s) in RCA: 556] [Impact Index Per Article: 79.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/27/2015] [Accepted: 12/17/2015] [Indexed: 02/06/2023]
Abstract
The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H2 O2 ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive Gi (e.g. responses to α2 -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive Gq (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H2 O2 ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.
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Affiliation(s)
- P. M. Vanhoutte
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong City Hong Kong
| | - H. Shimokawa
- Department of Cardiovascular Medicine; Tohoku University; Sendai Japan
| | - M. Feletou
- Department of Cardiovascular Research; Institut de Recherches Servier; Suresnes France
| | - E. H. C. Tang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong City Hong Kong
- School of Biomedical Sciences; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong City Hong Kong
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Vlachopoulos C, Xaplanteris P, Stefanadis C. Raloxifene, arterial function and Ockham's razor. Vascul Pharmacol 2013; 58:1-2. [DOI: 10.1016/j.vph.2012.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 11/10/2012] [Indexed: 11/26/2022]
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Cetinkaya Demir B, Uyar Y, Ozbilgin K, Köse C. Effect of raloxifene and atorvastatin in atherosclerotic process in ovariectomized rats. J Obstet Gynaecol Res 2012; 39:229-36. [PMID: 22845341 DOI: 10.1111/j.1447-0756.2012.01969.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM The goal of this study was to investigate the combined effects of raloxifene and atorvastatin in aged ovariectomized rats during endothelial dysfunction and atherosclerotic process. MATERIAL AND METHODS This study was conducted on 28 Wistar albino female rats randomly divided into four groups. All groups were ovariectomized and one group was kept as the control group (OVX). For four weeks, the remaining three groups were treated with the statin atorvastatin (OVX+AV), the selective estrogen receptor modulator raloxifene (OVX+RL), and both atorvastatin and raloxifene (OVX+RL+AV), respectively. At the end of the treatment period, all rats were sacrificed and thoracic aortas excised, and endothelial cells were immunohistochemically stained for markers in the atherosclerotic process, such as inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), endothelin-1 (ET-1), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor alpha (TNF-α). RESULTS Compared to the ovariectomized group, the iNOS level was significantly increased in the OVX+RL group (P=0.002), but contrarily decreased in the groups OVX+AV (P=0.002) and OVX+RL+AV (P=0.002). eNOS levels in the groups OVX+AV (P=0.002) and OVX+RL+AV (P=0.002) were significantly lower than that in the OVX group. When compared to the OVX group, significant reductions in ET-1 and TNF-α levels were found in all treatment groups. A significant decrement in MCP-1 level was found in the OVX+AV group (P=0.002). CONCLUSION In aged ovariectomized rats, the administration of both raloxifene and atorvastatin significantly decreased the levels of ET-1 and TNF-α on endothelial cells. Combined treatment with these drugs shortly after menopause might play a potential preventive role in the early stages of atherosclerosis development.
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Affiliation(s)
- Bilge Cetinkaya Demir
- Department of Obstetrics and Gynecology, Faculty of Medicine, Uludag University, Bursa, Turkey.
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Meyer MR, Prossnitz ER, Barton M. GPER/GPR30 and Regulation of Vascular Tone and Blood Pressure. ACTA ACUST UNITED AC 2011; 11:255-261. [PMID: 24999376 DOI: 10.2174/1871522211108040255] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Natural estrogens such as 17β-estradiol are endogenous vasodilators and have been implicated in the gender differences of hypertension. These hormones activate estrogen receptors ERα and ERβ, which mediate part of estrogen-dependent vasodilation. In addition, a novel G protein-coupled estrogen-binding receptor termed GPER/GPR30 has been identified that is expressed in the cardiovascular system. Using knock-out animals or drugs selectively targeting GPER/GPR30, a significant role for this receptor as a mediator of acute estrogen-dependent vasodilation involving nitric oxide (NO) and blood pressure-lowering activity has been demonstrated. The accumulating evidence that GPER/GPR30 is responsible for control of vascular tone indicates that this receptor may represent a novel drug target for pharmacologic treatment of hypertension in postmenopausal women and possibly also men.
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Affiliation(s)
- Matthias R Meyer
- Molecular Internal Medicine, University of Zurich, Zurich, Switzerland ; Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Eric R Prossnitz
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Matthias Barton
- Molecular Internal Medicine, University of Zurich, Zurich, Switzerland
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Cellular mechanisms of acute decrease of glutamate release induced by raloxifene in rat cerebral cortex. Neuropharmacology 2011; 61:293-304. [DOI: 10.1016/j.neuropharm.2011.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 03/29/2011] [Accepted: 04/12/2011] [Indexed: 11/24/2022]
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Meyer MR, Prossnitz ER, Barton M. The G protein-coupled estrogen receptor GPER/GPR30 as a regulator of cardiovascular function. Vascul Pharmacol 2011; 55:17-25. [PMID: 21742056 PMCID: PMC3216677 DOI: 10.1016/j.vph.2011.06.003] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 06/19/2011] [Accepted: 06/25/2011] [Indexed: 12/29/2022]
Abstract
Endogenous estrogens are important regulators of cardiovascular homeostasis in premenopausal women and delay the development of hypertension and coronary artery disease. These hormones act via three different estrogen receptors affecting both gene transcription and rapid signaling pathways in a complex interplay. In addition to the classical estrogen receptors ERα and ERβ, which are known mediators of estrogen-dependent vascular effects, a G protein-coupled estrogen receptor termed GPER that is expressed in the cardiovascular system has recently been identified. Endogenous human 17β-estradiol, selective estrogen receptor modulators (SERMs) including tamoxifen and raloxifene, and selective estrogen receptor downregulators (SERDs) such as ICI 182,780 are all agonists of GPER, which has been implicated in the regulation of vasomotor tone and protection from myocardial ischemia/reperfusion injury. As a result, understanding the individual role of ERα, ERβ, and GPER in cardiovascular function has become increasingly complex. With accumulating evidence that GPER is responsible for a variety of beneficial cardiovascular effects of estrogens, this receptor may represent a novel target to develop effective strategies for the treatment of cardiovascular diseases by tissue-specific, selective activation of estrogen-dependent molecular pathways devoid of side effects seen with conventional hormone therapy.
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Affiliation(s)
- Matthias R. Meyer
- Molecular Internal Medicine, University of Zurich, Zurich, Switzerland
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Eric R. Prossnitz
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Matthias Barton
- Molecular Internal Medicine, University of Zurich, Zurich, Switzerland
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Tang JY, Li S, Li ZH, Zhang ZJ, Hu G, Cheang LCV, Alex D, Hoi MPM, Kwan YW, Chan SW, Leung GPH, Lee SMY. Calycosin promotes angiogenesis involving estrogen receptor and mitogen-activated protein kinase (MAPK) signaling pathway in zebrafish and HUVEC. PLoS One 2010; 5:e11822. [PMID: 20686605 PMCID: PMC2912279 DOI: 10.1371/journal.pone.0011822] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 06/16/2010] [Indexed: 01/01/2023] Open
Abstract
Background Angiogenesis plays an important role in a wide range of physiological processes, and many diseases are associated with the dysregulation of angiogenesis. Radix Astragali is a Chinese medicinal herb commonly used for treating cardiovascular disorders and has been shown to possess angiogenic effect in previous studies but its active constituent and underlying mechanism remain unclear. The present study investigates the angiogenic effects of calycosin, a major isoflavonoid isolated from Radix Astragali, in vitro and in vivo. Methodology Tg(fli1:EGFP) and Tg(fli1:nEGFP) transgenic zebrafish embryos were treated with different concentrations of calycosin (10, 30, 100 µM) from 72 hpf to 96 hpf prior morphological observation and angiogenesis phenotypes assessment. Zebrafish embryos were exposed to calycosin (10, 100 µM) from 72 hpf to 78 hpf before gene-expression analysis. The effects of VEGFR tyrosine kinase inhibitor on calycosin-induced angiogenesis were studied using 72 hpf Tg(fli1:EGFP) and Tg(fli1:nEGFP) zebrafish embryos. The pro-angiogenic effects of calycosin were compared with raloxifene and tamoxifen in 72 hpf Tg(fli1:EGFP) zebrafish embryos. The binding affinities of calycosin to estrogen receptors (ERs) were evaluated by cell-free and cell-based estrogen receptor binding assays. Human umbilical vein endothelial cell cultures (HUVEC) were pretreated with different concentrations of calycosin (3, 10, 30, 100 µM) for 48 h then tested for cell viability and tube formation. The role of MAPK signaling in calycosin-induced angiogenesis was evaluated using western blotting. Conclusion Calycosin was shown to induce angiogenesis in human umbilical vein endothelial cell cultures (HUVEC) in vitro and zebrafish embryos in vivo via the up-regulation of vascular endothelial growth factor (VEGF), VEGFR1 and VEGFR2 mRNA expression. It was demonstrated that calycosin acted similar to other selective estrogen receptor modulators (SERMs), such as raloxifene and tamoxifen, by displaying selective potency and affinity to estrogen receptors ERα and ERβ. Our results further indicated that calycosin promotes angiogenesis via activation of MAPK with the involvement of ERK1/2 and ER. Together, this study revealed, for the first time, that calycosin acts as a selective estrogen receptor modulator (SERM) to promote angiogenesis, at least in part through VEGF-VEGFR2 and MAPK signaling pathways.
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Affiliation(s)
- Jing Yan Tang
- Institute of Chinese Medical Sciences, University of Macau, Macao, China
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9
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Chan YC, Leung FP, Wong WT, Tian XY, Yung LM, Lau CW, Tsang SY, Yao X, Chen ZY, Huang Y. Therapeutically relevant concentrations of raloxifene dilate pressurized rat resistance arteries via calcium-dependent endothelial nitric oxide synthase activation. Arterioscler Thromb Vasc Biol 2010; 30:992-9. [PMID: 20185791 DOI: 10.1161/atvbaha.110.203935] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Selective estrogen receptor modulators (SERMs) inhibit constriction of mammalian conduit arteries. However, it is unknown whether SERMs at therapeutically achievable concentrations could reduce vascular tone in resistance arteries. The present study aimed to examine roles of Ca(2+) influx in endothelium and endothelial nitric oxide synthase (eNOS) activation in dilatations induced by raloxifene, a second-generation SERM in myogenically active arteries. METHODS AND RESULTS Small mesenteric arteries from Sprague-Dawley rats were isolated and mounted in a pressure myograph for measurement of changes in vessel diameter. [Ca(2+)](i) images on native endothelial cells of intact arteries were determined by the fluorescence imaging technique, and phosphorylation of eNOS was assayed by Western blotting. Raloxifene (0.3 to 10 nmol/L) produced dilatations on established steady myogenic constriction. Female rat arteries dilated significantly more in response to raloxifene than male arteries. Raloxifene-induced dilatations of female arteries were blunted by N(G)-nitro-l-arginine methyl ester but unaffected by 1400W, charybdotoxin plus apamin, wortmannin, or LY294002. Raloxifene (3 nmol/L) triggered rises in endothelial cell [Ca(2+)](i) and increased eNOS phosphorylation at Ser1177. Both effects were greater in arteries from female rats than in arteries from male rats. Increases in endothelial cell [Ca(2+)](i) and in eNOS phosphorylation were prevented by removal of extracellular Ca(2+) ions. Finally, ICI 182,780 did not affect the raloxifene-stimulated rise in endothelial cell [Ca(2+)](i), eNOS phosphorylation, and vasodilatations. Chronic raloxifene treatment reduced myogenic constriction in arteries from female but not male rats. CONCLUSION Raloxifene at therapeutically relevant concentrations inhibits myogenic constriction by an NO-dependent mechanism that causally involves the elevated [Ca(2+)](i) in endothelial cells and subsequent eNOS activation. Raloxifene dilates resistance arteries more effectively in female rats, indicating its significant gender-related action on endothelial cells in microcirculation.
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Affiliation(s)
- Yau Chi Chan
- Institute of Vascular Medicine, Hong Kong, China
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Kim KH, Bender JR. Membrane-initiated actions of estrogen on the endothelium. Mol Cell Endocrinol 2009; 308:3-8. [PMID: 19549586 PMCID: PMC2701909 DOI: 10.1016/j.mce.2009.03.025] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 03/27/2009] [Accepted: 03/30/2009] [Indexed: 12/31/2022]
Abstract
Estrogen-induced rapid, membrane-initiated activation of numerous signal transduction cascades has been shown in animal, cellular and molecular vascular studies, which support the favorable effects of estrogen on vascular structure and function. These effects are mediated by distinct forms of estrogen receptor (ER) alpha. This includes estrogen-stimulated, rapid activation of endothelial nitric oxide synthase (eNOS), resulting in elaboration of the athero-protective, angiogenesis-promoting product nitric oxide (NO). An N-terminus truncated short isoform of ERalpha, ER46, plays a critical role in membrane-initiated, rapid responses to 17beta-estradiol (E2) in human endothelial cells (ECs). We have proposed a ER46-centered, eNOS-activating molecular complex in human EC caveolar membranes, containing c-Src, phosphatidylinositol 3-kinase (PI3K), Akt and eNOS. In this review, we describe estrogen-induced, rapid, non-genomic actions in the endothelium.
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Affiliation(s)
| | - Jeffrey R. Bender
- Corresponding author: Jeffrey R. Bender, Division of Cardiovascular Medicine and Departments of Internal Medicine and Immunobiology, Yale University School of Medicine, 300 Cedar Street, New Haven, Connecticut 06520, USA. Tel. 203-737-2223; Fax. 203-785-7567; E-Mail:
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Intapad S, Suksamrarn A, Piyachaturawat P. Enhancement of vascular relaxation in rat aorta by phytoestrogens from Curcuma comosa Roxb. Vascul Pharmacol 2009; 51:284-90. [PMID: 19665059 DOI: 10.1016/j.vph.2009.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 07/14/2009] [Accepted: 07/21/2009] [Indexed: 10/20/2022]
Abstract
The present study aims to examine the effects and mechanisms of Curcuma comosa Roxb., an indigenous medicinal plant containing phytoestrogens, on vascular relaxation. Using an organ bath system, acute exposure of intact or endothelium-denuded aortic rings to the hexane extract of C. comosa or an isolated diarylheptanoid compound, D3, did not induce relaxation. However, pre-incubation of aortic rings for 20 min with hexane extract of C. comosa (10 microg/ml) or the isolated diarylheptanoid compound, D3, (0.1, 1 and 10 microg/ml) markedly enhanced endothelial-dependent relaxation in response to ACh. The hexane extract did not modulate the relaxation of denuded aortic rings in response to SNP, which suggested a predominant effect on endothelial cells rather than on vascular smooth muscle cells. Co-incubation with ICI 182,780 (estrogen receptor antagonist), L-NAME (nitric oxide synthase inhibitor) or ODQ (guanylase cyclase inhibitor) inhibited the enhancing effects of C. comosa on ACh-induced relaxation. These findings suggest that the actions of C. comosa are mediated through estrogen receptor (ER) and NO-cGMP-dependent mechanisms. In addition, C. comosa also increased the phosphorylation of serine 1177 eNOS and serine 473 Akt proteins, and these effects were abolished by ICI 182,780. The results suggest that C. comosa acutely increases endothelium-dependent relaxation of aortic rings through the ER-Akt-eNOS pathway. This is the first evidence indicating non-genomic action of a novel phytoestrogen from C. comosa, on vascular relaxation.
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Affiliation(s)
- Suttira Intapad
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
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Abstract
The endothelium can evoke relaxations (dilatations) of the underlying vascular smooth muscle, by releasing vasodilator substances. The best characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO). The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDHF-mediated responses). Endothelium-dependent relaxations involve both pertussis toxin-sensitive G(i) (e.g. responses to serotonin and thrombin) and pertussis toxin-insensitive G(q) (e.g. adenosine diphosphate and bradykinin) coupling proteins. The release of NO by the endothelial cell can be up-regulated (e.g. by oestrogens, exercise and dietary factors) and down-regulated (e.g. oxidative stress, smoking and oxidized low-density lipoproteins). It is reduced in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively loose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and causing endothelium-dependent hyperpolarizations), endothelial cells also can evoke contraction (constriction) of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factor (EDCF). Most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells. EDCF-mediated responses are exacerbated when the production of NO is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive patients.
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Affiliation(s)
- P M Vanhoutte
- Department of Pharmacology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
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Moien-Afshari F, Ghosh S, Elmi S, Khazaei M, Rahman MM, Sallam N, Laher I. Exercise restores coronary vascular function independent of myogenic tone or hyperglycemic status in db/db mice. Am J Physiol Heart Circ Physiol 2008; 295:H1470-80. [PMID: 18641279 DOI: 10.1152/ajpheart.00016.2008] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Regulation of coronary function in diabetic hearts is an important component in preventing ischemic cardiac events but remains poorly studied. Exercise is recommended in the management of diabetes, but its effects on diabetic coronary function are relatively unknown. We investigated coronary artery myogenic tone and endothelial function, essential elements in maintaining vascular fluid dynamics in the myocardium. We hypothesized that exercise reduces pressure-induced myogenic constriction of coronary arteries while improving endothelial function in db/db mice, a model of type 2 diabetes. We used pressurized mouse coronary arteries isolated from hearts of control and db/db mice that were sedentary or exercised for 1 h/day on a motorized exercise-wheel system (set at 5.2 m/day, 5 days/wk). Exercise caused a approximately 10% weight loss in db/db mice and decreased whole body oxidative stress, as measured by plasma 8-isoprostane levels, but failed to improve hyperglycemia or plasma insulin levels. Exercise did not alter myogenic regulation of arterial diameter stimulated by increased transmural pressure, nor did it alter smooth muscle responses to U-46619 (a thromboxane agonist) or sodium nitroprusside (an endothelium-independent dilator). Moderate levels of exercise restored ACh-simulated, endothelium-dependent coronary artery vasodilation in db/db mice and increased expression of Mn SOD and decreased nitrotyrosine levels in hearts of db/db mice. We conclude that the vascular benefits of moderate levels of exercise were independent of changes in myogenic tone or hyperglycemic status and primarily involved increased nitric oxide bioavailability in the coronary microcirculation.
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Affiliation(s)
- Farzad Moien-Afshari
- Department of Pharmacology and Therapeutics, Faculty of Medicine,University of British Columbia, Vancouver, British Columbia, Canada
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Moien-Afshari F, Ghosh S, Elmi S, Rahman MM, Sallam N, Khazaei M, Kieffer TJ, Brownsey RW, Laher I. Exercise restores endothelial function independently of weight loss or hyperglycaemic status in db/db mice. Diabetologia 2008; 51:1327-37. [PMID: 18437348 DOI: 10.1007/s00125-008-0996-x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 02/25/2008] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Exercise ameliorates oxidative stress-mediated diabetic vascular endothelial dysfunction through poorly defined mechanisms. We hypothesised that, in addition to improving metabolic parameters, upregulation of antioxidants such as superoxide dismutase (SOD) mediates exercise-induced reductions of oxidative stress and increased nitric oxide (NO) bioavailability, and also restores vasodilatation. METHODS Type 2 diabetic db/db and normoglycaemic wild-type mice were exercised at moderate intensity for 1 h a day for 7 weeks, leading to a 10% body weight loss. Sedentary animals or those undergoing a low-intensity exercise regimen causing non-significant weight loss were also used. We examined aortic endothelial cell function, NO bioavailability and various biomarkers of oxidative stress. RESULTS Moderate-intensity exercise lowered body weight, increased mitochondrial manganese SOD (MnSOD) and both total and phosphorylated (Ser1177) endothelial nitric oxide synthase (eNOS) protein production; it also reduced whole-body (plasma 8-isoprostane) and tissue oxidative stress (nitrotyrosine immunostaining or protein carbonyl levels in the aorta). Low-intensity exercise did not alter body weight; however, it upregulated cytosolic Cu/Zn-SOD instead of MnSOD, and still demonstrated all the above benefits in the db/db aorta. Importantly, both exercise protocols improved endothelial-dependent vasodilatation and NO bioavailability without altering hyperglycaemic status in db/db mice. CONCLUSIONS/INTERPRETATION Exercise reverses diabetic vascular endothelial dysfunction independently of improvements in body weight or hyperglycaemia. Our data suggest that upregulation of eNOS and specific SOD isoforms could play important roles in improving NO bioavailability, as well as in reversing endothelial dysfunction in type 2 diabetes patients through lifestyle modifications in the management of diabetes.
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Affiliation(s)
- F Moien-Afshari
- Department of Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
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Wong CM, Yung LM, Leung FP, Tsang SY, Au CL, Chen ZY, Yao X, Cheng CHK, Lau CW, Gollasch M, Huang Y. Raloxifene protects endothelial cell function against oxidative stress. Br J Pharmacol 2008; 155:326-34. [PMID: 18574454 DOI: 10.1038/bjp.2008.262] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Maintaining a delicate balance between the generation of nitric oxide (NO) and removal of reactive oxygen species (ROS) within the vascular wall is crucial to the physiological regulation of vascular tone. Increased production of ROS reduces the effect and/or bioavailability of NO, leading to an impaired endothelial function. This study tested the hypothesis that raloxifene, a selective oestrogen receptor modulator, can prevent endothelial dysfunction under oxidative stress. EXPERIMENTAL APPROACH Changes in isometric tension were measured in rat aortic rings. The content of cyclic GMP in aortic tissue was determined by radioimmunoassay. Phosphorylation of endothelial NOS (eNOS) and Akt was assayed by Western blot analysis. KEY RESULTS In rings with endothelium, ACh-induced relaxations were attenuated by a ROS-generating reaction (hypoxanthine plus xanthine oxidase, HXXO). The impaired relaxations were ameliorated by acute treatment with raloxifene. HXXO suppressed the ACh-stimulated increase in cyclic GMP levels; this effect was antagonized by raloxifene. The improved endothelial function by raloxifene was abolished by ICI 182,780, and by wortmannin or LY294002. Raloxifene also protected endothelial cell function against H2O2. Raloxifene increased the phosphorylation of eNOS at Ser-1177 and Akt at Ser-473; this effect was blocked by ICI 182,780. Finally, raloxifene was not directly involved in scavenging ROS, and neither inhibited the activity of xanthine oxidase nor stimulated that of superoxide dismutase. CONCLUSION AND IMPLICATIONS Raloxifene is effective against oxidative stress-induced endothelial dysfunction in vitro through an ICI 182,780-sensitive mechanism that involves the increased phosphorylation and activity of Akt and eNOS in rat aortae.
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Affiliation(s)
- C M Wong
- Institute of Vascular Medicine and Department of Physiology, Chinese University of Hong Kong, Hong Kong, China
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