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Carpéné C, Viana P, Fontaine J, Laurell H, Grolleau JL. Multiple Direct Effects of the Dietary Protoalkaloid N-Methyltyramine in Human Adipocytes. Nutrients 2022; 14:nu14153118. [PMID: 35956295 PMCID: PMC9370673 DOI: 10.3390/nu14153118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/23/2022] [Accepted: 07/27/2022] [Indexed: 02/06/2023] Open
Abstract
Dietary amines have been the subject of a novel interest in nutrition since the discovery of trace amine-associated receptors (TAARs), especially TAAR-1, which recognizes tyramine, phenethylamine, tryptamine, octopamine, N-methyltyramine (NMT), synephrine, amphetamine and related derivatives. Alongside the psychostimulant properties of TAAR-1 ligands, it is their ephedrine-like action on weight loss that drives their current consumption via dietary supplements advertised for ‘fat-burning’ properties. Among these trace amines, tyramine has recently been described, at high doses, to exhibit an antilipolytic action and activation of glucose transport in human adipocytes, i.e., effects that are facilitating lipid storage rather than mobilization. Because of its close structural similarity to tyramine, NMT actions on human adipocytes therefore must to be reevaluated. To this aim, we studied the lipolytic and antilipolytic properties of NMT together with its interplay with insulin stimulation of glucose transport along with amine oxidase activities in adipose cells obtained from women undergoing abdominal surgery. NMT activated 2-deoxyglucose uptake when incubated with freshly isolated adipocytes at 0.01–1 mM, reaching one-third of the maximal stimulation by insulin. However, when combined with insulin, NMT limited by half the action of the lipogenic hormone on glucose transport. The NMT-induced stimulation of hexose uptake was sensitive to inhibitors of monoamine oxidases (MAO) and of semicarbazide-sensitive amine oxidase (SSAO), as was the case for tyramine and benzylamine. All three amines inhibited isoprenaline-induced lipolysis to a greater extent than insulin, while they were poorly lipolytic on their own. All three amines—but not isoprenaline—interacted with MAO or SSAO. Due to these multiple effects on human adipocytes, NMT cannot be considered as a direct lipolytic agent, potentially able to improve lipid mobilization and fat oxidation in consumers of NMT-containing dietary supplements.
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Affiliation(s)
- Christian Carpéné
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1297), I2MC, CEDEX 4, 31432 Toulouse, France; (P.V.); (J.F.); (H.L.)
- CHU Rangueil, Université Paul Sabatier, I2MC, CEDEX 4, 31432 Toulouse, France
- Correspondence:
| | - Pénélope Viana
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1297), I2MC, CEDEX 4, 31432 Toulouse, France; (P.V.); (J.F.); (H.L.)
- CHU Rangueil, Université Paul Sabatier, I2MC, CEDEX 4, 31432 Toulouse, France
| | - Jessica Fontaine
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1297), I2MC, CEDEX 4, 31432 Toulouse, France; (P.V.); (J.F.); (H.L.)
- CHU Rangueil, Université Paul Sabatier, I2MC, CEDEX 4, 31432 Toulouse, France
| | - Henrik Laurell
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1297), I2MC, CEDEX 4, 31432 Toulouse, France; (P.V.); (J.F.); (H.L.)
- CHU Rangueil, Université Paul Sabatier, I2MC, CEDEX 4, 31432 Toulouse, France
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Matsumoto T, Takayanagi K, Kojima M, Taguchi K, Kobayashi T. Mechanisms underlying suppression of noradrenaline-induced contraction by prolonged treatment with advanced glycation end-products in organ-cultured rat carotid artery. Pflugers Arch 2020; 472:355-366. [DOI: 10.1007/s00424-020-02349-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/30/2019] [Accepted: 01/14/2020] [Indexed: 01/11/2023]
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Ye F, Wu Y, Chen Y, Xiao D, Shi L. Impact of moderate- and high-intensity exercise on the endothelial ultrastructure and function in mesenteric arteries from hypertensive rats. Life Sci 2019; 222:36-45. [PMID: 30825543 DOI: 10.1016/j.lfs.2019.01.058] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/16/2019] [Accepted: 01/16/2019] [Indexed: 12/20/2022]
Abstract
Oxidative stress (OS) influences vascular function and structure in spontaneously hypertensive rats (SHRs). It is also responsible for the decreased nitric oxide (NO) bioavailability that influences endothelial vasodilation. The effects of high-intensity exercise on endothelial function and ultrastructure in hypertension remain unknown. Thus, this study investigated the effects of moderate- and high-intensity exercise on hypertension-associated endothelial dysfunction and ultrastructural remodeling. Moderate-intensity (SHR-M) and high-intensity (SHRH) aerobic exercise training groups were compared in age-matched sedentary SHRs (SHRC) and normotensive Wistar-Kyoto rats (WKY-C). The results showed that the endothelial ultrastructure was impaired in the SHR-H and SHR-C groups. Glutathione peroxidase levels were significantly increased in the SHR-M group compared to the SHR-C group. MDA content was higher in the SHR-H group than in the SHR-C group, but the levels of antioxidant enzymes did not increase accordingly. Apocynin scavenging reactive oxygen species (ROS) ameliorated endothelium-dependent vasodilator function in the SHR-H group. However, the SHR-M and WKY-C groups abolished the increased vasodilation induced by apocynin. L-NAME, a NO synthase inhibitor, was applied to isolated mesenteric arteries (MAs) to evaluate NO contribution. Moderate-intensity exercise reversed the decreased NO contribution to MAs in hypertension, and high-intensity exercise aggravated this change. These data suggest that moderate-intensity exercise ameliorated adverse remodeling of the endothelial ultrastructure and function in hypertension by decreasing oxidative stress and increasing NO contribution. However, high-intensity exercise exacerbated all of these changes by increasing OS and ROS contribution, and decreasing NO contribution.
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Affiliation(s)
- Fang Ye
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Ying Wu
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Yu Chen
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Daliao Xiao
- Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.
| | - Lijun Shi
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China.
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Craighead DH, Wang H, Santhanam L, Alexander LM. Acute lysyl oxidase inhibition alters microvascular function in normotensive but not hypertensive men and women. Am J Physiol Heart Circ Physiol 2018; 314:H424-H433. [PMID: 29167120 PMCID: PMC5899263 DOI: 10.1152/ajpheart.00521.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The lysyl oxidase (LOX) family of enzymes regulates collagen cross-linking. LOX is upregulated in hypertension, increasing vascular stiffness. In vivo human research is sparse, as long-term LOX inhibition in animals causes vascular instability. Our aim was to evaluate the effects of LOX inhibition on cutaneous microvascular function to determine whether LOX function was upregulated in hypertensive humans. Four intradermal microdialysis fibers were placed in the forearm of 10 young [age: 24 ± 1 yr, mean arterial pressure (MAP): 87 ± 2 mmHg], 10 normotensive (age: 50 ± 2 yr, MAP: 84 ± 1 mmHg), and 10 hypertensive (age: 53 ± 2 yr, MAP: 112 ± 2 mmHg) subjects. Two sites were perfused with 10 mM β-aminopropionitrile (BAPN) to inhibit LOX. The remaining two sites were perfused with lactated Ringer solution (control). A norepinephrine dose response (10-12-10-2 M) was performed to examine receptor-mediated vasoconstrictor function. A sodium nitroprusside dose response (10-8-10-1.3 M) was performed to examine vascular smooth muscle vasodilator function. Red blood cell flux was measured via laser-Doppler flowmetry and normalized to cutaneous vascular conductance (flux/MAP). LogEC50 values were calculated to determine changes in vasosensitivity. Skin tissue samples were analyzed for both extracellular matrix-bound and soluble LOX. LOX inhibition augmented vasoconstrictor sensitivity in young (control: -6.0 and BAPN: -7.1, P = 0.03) and normotensive (control: -4.8 and BAPN: -7.0, P = 0.01) but not hypertensive (control: -6.0 and BAPN: -6.1, P = 0.79) men and women. Relative to young subjects, extracellular matrix-bound LOX expression was higher in hypertensive subjects (young: 100 ± 8 and hypertensive: 162 ± 8, P = 0.002). These results suggest that upregulated LOX may contribute to the vascular stiffness and microvascular dysfunction characteristic in hypertension. NEW & NOTEWORTHY Matrix-bound lysyl oxidase (LOX) and LOX-like 2 expression are upregulated in the microvasculature of hypertensive men and women. Microvascular responsiveness to exogenous stimuli is altered with localized LOX inhibition in healthy men and women but not hypertensive adults. The LOX family differentially affects microvascular function in hypertensive and normotensive men and women.
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Affiliation(s)
| | - Huilei Wang
- Johns Hopkins University School of Medicine , Baltimore, Maryland
| | | | - Lacy M Alexander
- The Pennsylvania State University , University Park, Pennsylvania
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Fedchenko V, Medvedev A. Comparative analysis of expression of genes encoding enzymes of catecholamine catabolism and renalase in tissues of normotensive and hypertensive rats. ACTA ACUST UNITED AC 2017; 63:312-315. [DOI: 10.18097/pbmc20176304312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Comparative analysis of expression of genes encoding enzymes of catecholamine catabolism (monoaminbe oxidases A and B (MAO A and MAO B) and catechol-O-methyl transferase (COMT)) and renalase has been carried out in tissues of normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). Among investigated tissues the highest level of mRNA of genes encoding key enzymes of catecholamine catabolism (MAO A, MAO B, COMT) was found in the heart of WKY rats. In SHR the mRNA levels of these genes were lower (p<0.05-0.01), however, no similar changes were observed in the tissues studied in dependence of hypertension. The relative mRNA levels of the studied genes normalized versus actin mRNA significantly varied. In heart and kidney the relative level of COMT mRNA significantly exceeded the relative levels of both MAO A mRNA and MAO B mRNA. In the brain differences in mRNAs of MAOA, MAOB, and COMT were less pronounced. However, in all examined tissue the renalase mRNA level was much (at least 10-20-fold) lower than any other mRNA studied. Taking into consideration known correlations between mRNAs and corresponding protein products reported in the literature for many genes these results suggest that in the case of any catalytic scenarios proposed or even proved for renalase this protein cannot contribute to catecholamine degradation. It is also unlikely that the products of renalase reaction, b-NAD(P)+ and hydrogen peroxide, can exhibit a hypotensive effect due to low expression of the renalase encoding gene.
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Ardanaz N, Pagano PJ. Hydrogen Peroxide as a Paracrine Vascular Mediator: Regulation and Signaling Leading to Dysfunction. Exp Biol Med (Maywood) 2016; 231:237-51. [PMID: 16514169 DOI: 10.1177/153537020623100302] [Citation(s) in RCA: 166] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Numerous studies have demonstrated the ability of a variety of vascular cells, including endothelial cells, smooth muscle cells, and fibroblasts, to produce reactive oxygen species (ROS). Until recently, major emphasis was placed on the production of superoxide anion (O2–) in the vasculature as a result of its ability to directly attenuate the biological activity of endothelium-derived nitric oxide (NO). The short half-life and radius of diffusion of O2– drastically limit the role of this ROS as an important paracrine hormone in vascular biology. On the contrary, in recent years, the O2– metabolite hydrogen peroxide (H2O2) has increasingly been viewed as an important cellular signaling agent in its own right, capable of modulating both contractile and growth-promoting pathways with more far-reaching effects. In this review, we will assess the vascular production of H2O2, its regulation by endogenous scavenger systems, and its ability to activate a variety of vascular signaling pathways, thereby leading to vascular contraction and growth. This discussion will include the ability of H2O2 to (i) Initiate calcium flux as well as (ii) stimulate pathways leading to sensitization of contractile elements to calcium. The latter involves a variety of protein kinases that have also been strongly implicated in vascular hypertrophy. Previous Intensive study has emphasized the ability of NADPH oxidase-derived O2– and H2O2 to activate these pathways in cultured smooth muscle cells. However, growing evidence indicates a considerably more complex array of unique oxidase systems in the endothelium, media, and adventitia that appear to participate in these deleterious effects in a sequential and temporal manner. Taken together, these findings seem consistent with a paracrine effect of H2O2 across the vascular wall.
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Affiliation(s)
- Noelia Ardanaz
- Hypertension and Vascular Research Division, RM 7044, E&R Building, Henry Ford Hospital, 2799 West Grand Boulevard, Detroit, MI 48202-2689, USA
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Nguyen Dinh Cat A, Antunes TT, Callera GE, Sanchez A, Tsiropoulou S, Dulak-Lis MG, Anagnostopoulou A, He Y, Montezano AC, Jaisser F, Touyz RM. Adipocyte-Specific Mineralocorticoid Receptor Overexpression in Mice Is Associated With Metabolic Syndrome and Vascular Dysfunction: Role of Redox-Sensitive PKG-1 and Rho Kinase. Diabetes 2016; 65:2392-403. [PMID: 27207514 DOI: 10.2337/db15-1627] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 04/09/2016] [Indexed: 11/13/2022]
Abstract
Mineralocorticoid receptor (MR) expression is increased in adipose tissue from obese individuals and animals. We previously demonstrated that adipocyte-MR overexpression (Adipo-MROE) in mice is associated with metabolic changes. Whether adipocyte MR directly influences vascular function in these mice is unknown. We tested this hypothesis in resistant mesenteric arteries from Adipo-MROE mice using myography and in cultured adipocytes. Molecular mechanisms were probed in vessels/vascular smooth muscle cells and adipose tissue/adipocytes and focused on redox-sensitive pathways, Rho kinase activity, and protein kinase G type-1 (PKG-1) signaling. Adipo-MROE versus control-MR mice exhibited reduced vascular contractility, associated with increased generation of adipocyte-derived hydrogen peroxide, activation of vascular redox-sensitive PKG-1, and downregulation of Rho kinase activity. Associated with these vascular changes was increased elastin content in Adipo-MROE. Inhibition of PKG-1 with Rp-8-Br-PET-cGMPS normalized vascular contractility in Adipo-MROE. In the presence of adipocyte-conditioned culture medium, anticontractile effects of the adipose tissue were lost in Adipo-MROE mice but not in control-MR mice. In conclusion, adipocyte-MR upregulation leads to impaired contractility with preserved endothelial function and normal blood pressure. Increased elasticity may contribute to hypocontractility. We also identify functional cross talk between adipocyte MR and arteries and describe novel mechanisms involving redox-sensitive PKG-1 and Rho kinase. Our results suggest that adipose tissue from Adipo-MROE secrete vasoactive factors that preferentially influence vascular smooth muscle cells rather than endothelial cells. Our findings may be important in obesity/adiposity where adipocyte-MR expression/signaling is amplified and vascular risk increased.
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Affiliation(s)
- Aurelie Nguyen Dinh Cat
- Cardiovascular Research and Medical Sciences Institute, University of Glasgow, Glasgow, U.K.
| | - Tayze T Antunes
- Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Glaucia E Callera
- Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Ana Sanchez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Sofia Tsiropoulou
- Cardiovascular Research and Medical Sciences Institute, University of Glasgow, Glasgow, U.K
| | - Maria G Dulak-Lis
- Cardiovascular Research and Medical Sciences Institute, University of Glasgow, Glasgow, U.K
| | | | - Ying He
- Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Augusto C Montezano
- Cardiovascular Research and Medical Sciences Institute, University of Glasgow, Glasgow, U.K
| | - Frederic Jaisser
- INSERM Unit 1138 Team 1, Centre de Recherche des Cordeliers, University Pierre and Marie Curie, Paris, France INSERM, Clinical Investigation Centre 1430, APHP, Henri Mondor Hospital, Pole VERDI, Paris East University, Creteil, France
| | - Rhian M Touyz
- Cardiovascular Research and Medical Sciences Institute, University of Glasgow, Glasgow, U.K. Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
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Severina IS, Fedchenko VI, Veselovsky AV, Medvedev AE. [The history of renalase from amine oxidase to a a-NAD(P)H-oxidase/anomerase]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2016; 61:667-79. [PMID: 26716738 DOI: 10.18097/pbmc20156106667] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Renalase is a recently discovered secretory protein, which plays a certain (still poorly understood) role in regulation of blood pressure. The review summarizes own and literature data accumulated since the first publication on relanase (2005). Initial reports on FAD-dependent amine oxidase activity of this protein were not confirmed in independent experiments performed in different laboratories. In addition, proposed amine oxidase activity of circulating extracellular renalase requires the presence of FAD, which has not been detected either in blood or urinary renalase. Moreover, renalase excreted into urine lacks its N-terminal peptide, which is ultimately needed for accommodation of the FAD cofactor. Results of the Aliverti's group on NAD(P)H binding by renalase and weak diaphorase activity of this protein stimulated further studies of renalase as NAD(P)H oxidase catalyzing reaction of catecholamine co-oxidation. However, physiological importance of such extracellular catecholamine-metabolizing activity (demonstrated in one laboratory and not detected in another laboratory) remains unclear due to existence of much more active enzymatic systems (e.g. neutrophil NAD(P)H oxidase, xanthine oxidase/xanthine) in circulation, which can perform such co-oxidation reactions. Recently a-NAD(P)H oxidase/anomerase activity of renalase, which also pomotes oxidative conversion of b-NADH isomers inhibiting activity of NAD-dependent dehydrogenases, has been described. However, its possible contribution to the antihypertensive effect of renalase remains unclear. Thus, the antihypertensive effect of renalase still remains a phenomenon with unclear biochemical mechanim(s) and functions of intracellular and extracellular (circulating) renalases obviously differ.
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Affiliation(s)
- I S Severina
- Institute of Biomedical Chemistry, Moscow, Russia
| | | | | | - A E Medvedev
- Institute of Biomedical Chemistry, Moscow, Russia
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Chuaiphichai S, McNeill E, Douglas G, Crabtree MJ, Bendall JK, Hale AB, Alp NJ, Channon KM. Cell-autonomous role of endothelial GTP cyclohydrolase 1 and tetrahydrobiopterin in blood pressure regulation. Hypertension 2014; 64:530-40. [PMID: 24777984 PMCID: PMC5238938 DOI: 10.1161/hypertensionaha.114.03089] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tetrahydrobiopterin (BH4) is an essential cofactor for endothelial nitric oxide synthase (eNOS) function and NO generation. Augmentation of BH4 levels can prevent eNOS uncoupling and can improve endothelial dysfunction in vascular disease states. However, the physiological requirement for de novo endothelial cell BH4 biosynthesis in eNOS function remains unclear. We generated a novel mouse model with endothelial cell-specific deletion of GCH1, encoding GTP cyclohydrolase 1, an essential enzyme for BH4 biosynthesis, to test the cell-autonomous requirement for endothelial BH4 biosynthesis in vivo. Mice with a floxed GCH1 allele (GCH1(fl/fl)) were crossed with Tie2cre mice to delete GCH1 in endothelial cells. GCH1(fl/fl)Tie2cre mice demonstrated virtually absent endothelial NO bioactivity and significantly greater O2 (•-) production. GCH1(fl/fl)Tie2cre aortas and mesenteric arteries had enhanced vasoconstriction to phenylephrine and impaired endothelium-dependent vasodilatations to acetylcholine and SLIGRL. Endothelium-dependent vasodilatations in GCH1(fl/fl)Tie2cre aortas were, in part, mediated by eNOS-derived hydrogen peroxide (H2O2), which mediated vasodilatation through soluble guanylate cyclase. Ex vivo supplementation of aortic rings with the BH4 analogue sepiapterin restored normal endothelial function and abolished eNOS-derived H2O2 production in GCH1(fl/fl)Tie2cre aortas. GCH1(fl/fl)Tie2cre mice had higher systemic blood pressure than wild-type littermates, which was normalized by NOS inhibitor, NG-nitro-L-arginine methyl ester. Taken together, these studies reveal an endothelial cell-autonomous requirement for GCH1 and BH4 in regulation of vascular tone and blood pressure and identify endothelial cell BH4 as a pivotal regulator of NO versus H2O2 as alternative eNOS-derived endothelial-derived relaxing factors.
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Affiliation(s)
- Surawee Chuaiphichai
- From the British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Eileen McNeill
- From the British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Gillian Douglas
- From the British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Mark J Crabtree
- From the British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Jennifer K Bendall
- From the British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Ashley B Hale
- From the British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Nicholas J Alp
- From the British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Keith M Channon
- From the British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
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d'Uscio LV, He T, Santhanam AVR, Tai LJ, Evans RM, Katusic ZS. Mechanisms of vascular dysfunction in mice with endothelium-specific deletion of the PPAR-δ gene. Am J Physiol Heart Circ Physiol 2014; 306:H1001-10. [PMID: 24486511 PMCID: PMC3962632 DOI: 10.1152/ajpheart.00761.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/27/2014] [Indexed: 02/06/2023]
Abstract
Peroxisome proliferator-activated receptor (PPAR)-δ is a nuclear hormone receptor that is mainly involved in lipid metabolism. Recent studies have suggested that PPAR-δ agonists exert vascular protective effects. The present study was designed to characterize vascular function in mice with genetic inactivation of PPAR-δ in the endothelium. Mice with vascular endothelial cell-specific deletion of the PPAR-δ gene (ePPARδ(-/-) mice) were generated using loxP/Cre technology. ePPARδ(-/-) mice were normotensive and did not display any sign of metabolic syndrome. Endothelium-dependent relaxations to ACh and endothelium-independent relaxations to the nitric oxide (NO) donor diethylammonium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate were both significantly impaired in the aorta and carotid arteries of ePPARδ(-/-) mice (P < 0.05). In ePPARδ(-/-) mouse aortas, phosphorylation of endothelial NO synthase at Ser(1177) was significantly decreased (P < 0.05). However, basal levels of cGMP were unexpectedly increased (P < 0.05). Enzymatic activity of GTP-cyclohydrolase I and tetrahydrobiopterin levels were also enhanced in ePPARδ(-/-) mice (P < 0.05). Most notably, endothelium-specific deletion of the PPAR-δ gene significantly decreased protein expressions of catalase and glutathione peroxidase 1 and resulted in increased levels of H2O2 in the aorta (P < 0.05). In contrast, superoxide anion production was unaltered. Moreover, treatment with catalase prevented the endothelial dysfunction and elevation of cGMP detected in aortas of ePPARδ(-/-) mice. The findings suggest that increased levels of cGMP caused by H2O2 impair vasodilator reactivity to endogenous and exogenous NO. We speculate that chronic elevation of H2O2 predisposes PPAR-δ-deficient arteries to oxidative stress and vascular dysfunction.
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Affiliation(s)
- Livius V d'Uscio
- Department of Anesthesiology and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota; and
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Wheal AJ, Alexander SPH, Randall MD. Hydrogen peroxide as a mediator of vasorelaxation evoked by N-oleoylethanolamine and anandamide in rat small mesenteric arteries. Eur J Pharmacol 2011; 674:384-90. [PMID: 22154756 DOI: 10.1016/j.ejphar.2011.11.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 11/09/2011] [Accepted: 11/16/2011] [Indexed: 12/31/2022]
Abstract
Hydrogen peroxide (H(2)O(2)) has been shown to participate in endothelium-derived hyperpolarising factor (EDHF)-mediated mechanisms. Vasorelaxation to the endocannabinoid-like N-oleoylethanolamine (OEA) and anandamide has been shown to be endothelium-dependent. Therefore, the principal aim was to investigate whether H(2)O(2) plays a role in vasorelaxation to endocannabinoids in rat mesenteric arteries. We have also investigated the effects of catalase on endothelium-dependent relaxations and vascular responses to H(2)O(2). First- (G1) and third- (G3) order branches of the superior mesenteric artery from male, Wistar rats were mounted in a wire myograph, contracted with methoxamine, and concentration-response curves to anandamide, OEA carbachol or H(2)O(2), were constructed. The influence of nitric oxide production and H(2)O(2) breakdown on these responses were then investigated using L-NAME (300 μM), and catalase (1000 Uml(-1)) respectively. In G1 mesenteric arteries, vasorelaxations to carbachol and H(2)O(2) were inhibited by L-NAME, but not by catalase. Responses to both anandamide and OEA were also unaffected by catalase. In G3 mesenteric arteries, endothelium-dependent relaxations to carbachol were modestly affected by L-NAME, unaffected by catalase alone, but their combination greatly inhibited vasorelaxation. Similarly, catalase inhibited vasorelaxation to anandamide and OEA, and combined treatment with L-NAME further reduced this response. In G1 mesenteric arteries, vasorelaxation to H(2)O(2) is predominantly mediated by nitric oxide. We conclude that in G3 arteries H(2)O(2) activity contributes towards EDHF-type responses and vasorelaxation to endocannabinoids, either directly or indirectly. Given the association between vascular pathophysiology and H(2)O(2), these findings may provide a mechanism whereby disease states may influence responses to endocannabinoid and related mediators.
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Affiliation(s)
- Amanda J Wheal
- Cardiovascular Research Group, School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, United Kingdom
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Félétou M. The Endothelium, Part I: Multiple Functions of the Endothelial Cells -- Focus on Endothelium-Derived Vasoactive Mediators. ACTA ACUST UNITED AC 2011. [DOI: 10.4199/c00031ed1v01y201105isp019] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Mori-Kawabe M, Tsushima H, Fujimoto S, Tada T, Ito JI. Role of Rho/Rho-kinase and NO/cGMP signaling pathways in vascular function prior to atherosclerosis. J Atheroscler Thromb 2009; 16:722-32. [PMID: 19755789 DOI: 10.5551/jat.1875] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AIM Atherosclerosis is a cardiovascular disease; however, there is little information on signal transduction for vascular function in the early stage of atherosclerosis. In this work, we investigated the role of Rho/Rho-kinase and nitrogen oxide (NO)/cyclic GMP (cGMP) signaling pathways in the aorta prior to atherosclerosis. METHODS Tension, the expression of RhoA protein, Rho-kinase activity and the cGMP level were measured using endothelium-intact or -denuded aorta prepared from apolipoprotein E-deficient (apoE-KO) and C57BL/6 wild-type (WT) mice at 2 months of age. RESULTS Phenylephrine (PE) induced less maximal contraction in the endothelium-denuded aorta from apoE-KO than from WT mice. A Rho-kinase inhibitor (Y-27632) reduced more effectively the contraction of apoE-KO than WT mice, but their RhoA proteins and Rho-kinase activities were not so different. Acetylcholine caused larger relaxation of the PE-stimulated, endothelium-intact aorta in apoE-KO due to endothelial NO release than WT mice. The basal cGMP level in the endothelium-intact aorta of apoE-KO mice was higher than that of WT. CONCLUSIONS Smooth muscle contraction via alpha(1)-adrenergic receptor shows higher dependency on Rho-kinase activity, suggesting down-regulation of the mechanism different from Rho/Rho kinase signaling in the aorta prior to atherosclerosis. Endothelium-dependent relaxation is also intensified through the NO/cGMP pathway.
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Affiliation(s)
- Mayumi Mori-Kawabe
- Department of Cellular and Molecular Pharmacology, Nagoya City University Graduate School of Medical Sciences, Japan.
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15
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Fujimoto S, Mori M, Tsushima H, Kunimatsu M. Capsaicin-induced, capsazepine-insensitive relaxation of the guinea-pig ileum. Eur J Pharmacol 2005; 530:144-51. [PMID: 16360146 DOI: 10.1016/j.ejphar.2005.11.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 11/01/2005] [Accepted: 11/03/2005] [Indexed: 11/30/2022]
Abstract
The mechanisms underlying transient receptor potential vanilloid receptor type 1 (TRPV1)-independent relaxation elicited by capsaicin were studied by measuring isometric force and phosphorylation of 20-kDa regulatory light chain subunit of myosin (MLC(20)) in ileum longitudinal smooth muscles of guinea-pigs. In acetylcholine-stimulated tissues, capsaicin (1-100 microM) and resiniferatoxin (10 nM-1 microM) produced a concentration-dependent relaxation. The relaxant response was attenuated by 4-aminopyridine and high-KCl solution, but not by capsazepine, tetraethylammonium, Ba(2+), glibenclamide, charybdotoxin plus apamin nor antagonists of cannabinoid receptor type 1 and calcitonin-gene related peptide. A RhoA kinase inhibitor reduced the relaxant effect of capsaicin at 30 microM. Capsaicin and resiniferatoxin reduced acetylcholine- and caffeine-induced transient contractions in a Ca(2+)-free, EGTA solution. Capsaicin at 30 microM for 20 min did not alter basal levels of MLC(20) phosphorylation, but abolished an increase by acetylcholine in MLC(20) phosphorylation. It is suggested that the relaxant effect of capsaicin at concentrations used is not mediated by TRPV1, but by 4-aminopyridine-sensitive K(+) channels, and that capsaicin inhibits contractile mechanisms involving Ca(2+) release from intracellular storage sites. The relaxation could be explained by a decrease in phosphorylation of MLC(20).
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Affiliation(s)
- Seigo Fujimoto
- Department of Cellular and Molecular Pharmacology, Nagoya City University Graduate School of Medical Sciences, Kawasumi, Mizuho-cho, Mizuho-ku, Japan.
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16
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Ling X, Cota-Gomez A, Flores NC, Hernandez-Saavedra D, McCord JM, Marecki JC, Haskins K, McDuffie M, Powers K, Kench J, Oka M, McMurtry I, Flores SC. Alterations in redox homeostasis and prostaglandins impair endothelial-dependent vasodilation in euglycemic autoimmune nonobese diabetic mice. Free Radic Biol Med 2005; 39:1089-98. [PMID: 16198235 DOI: 10.1016/j.freeradbiomed.2005.05.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 05/24/2005] [Accepted: 05/24/2005] [Indexed: 10/25/2022]
Abstract
We report herein the novel observation that alterations in oxidant/antioxidant balance are evident and cause vascular dysfunction in aortae of prediabetic nonobese-diabetic mice (NOD). We found that nitrotyrosine, a biochemical marker of oxidant stress, was higher in the NOD aortae when compared to age-matched non-autoimmune BALB/c controls or the diabetes-resistant NOD congenic strain, NOD.Lc7. The oxidant stress was localized to the intimal and medial layers, and endothelium-dependent relaxation to acetylcholine was decreased in isolated aortic rings from NOD mice. Inhibition of nitric oxide synthesis caused an endothelium-dependent contraction, and treatment with either a selective thromboxane A2/prostaglandin H2 receptor antagonist or a non-isozyme-specific cyclooxygenase inhibitor reversed this effect. Aortic rings from NOD.Lc7 did not display the paradoxical vasoconstriction. Furthermore, the vascular dysfunction was caused by oxidative stress, as treatment with a superoxide dismutase mimetic in vivo or with native antioxidant enzymes ex vivo inhibited the tissue oxidant stress and restored endothelium-dependent relaxation. Endothelial function was also restored by the inhibitors of NAD(P)H oxidase, diphenylene iodonium or apocynin. Our studies indicate that an oxidant stress that occurs prior to the onset of diabetes in this mouse model contributes to endothelial dysfunction independently of overt diabetes.
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MESH Headings
- Acetophenones/pharmacology
- Acetylcholine/pharmacology
- Animals
- Aorta/chemistry
- Aorta/drug effects
- Aorta/physiopathology
- Cyclooxygenase Inhibitors/pharmacology
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/physiopathology
- Endothelium, Vascular/chemistry
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiopathology
- Homeostasis
- Mice
- Mice, Inbred BALB C
- Mice, Inbred NOD
- NADPH Oxidases/antagonists & inhibitors
- NADPH Oxidases/metabolism
- Nitric Oxide/metabolism
- Onium Compounds/pharmacology
- Oxidation-Reduction
- Oxidative Stress
- Prediabetic State/metabolism
- Prediabetic State/physiopathology
- Prostaglandin-Endoperoxide Synthases/metabolism
- Prostaglandins/metabolism
- Receptors, Thromboxane A2, Prostaglandin H2/antagonists & inhibitors
- Receptors, Thromboxane A2, Prostaglandin H2/metabolism
- Tyrosine/analogs & derivatives
- Tyrosine/analysis
- Tyrosine/metabolism
- Vasodilation
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Affiliation(s)
- Xiaofeng Ling
- Webb-Waring Institute for Cancer, Aging and Antioxidant Research, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Box C-321, Denver, CO 80262, USA
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17
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Lucchesi PA, Belmadani S, Matrougui K. Hydrogen peroxide acts as both vasodilator and vasoconstrictor in the control of perfused mouse mesenteric resistance arteries. J Hypertens 2005; 23:571-9. [PMID: 15716699 DOI: 10.1097/01.hjh.0000160214.40855.79] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Hydrogen peroxide (H2O2) plays a key role in the control of resistance artery (RA) tone and is hypothesized as an endothelial-derived hyperpolarizing factor. METHODS In this study, we investigated the effects of the same concentration of exogenous H2O2 on mouse mesenteric RA tone induced by intraluminal pressure, G-protein coupled receptor activation and KCl. RAs were cannulated in an arteriograph in the absence or presence of vasoconstrictors. RESULTS RA developed myogenic tone (MT) in response to stepwise pressure increases. Under phenylephrine, H2O2 induced a dose-dependent (1-50 micromol/l) vasodilation with maximum dilation at 50 micromol/l. H2O2 at 50 micromol/l induced a full dilation of RA under MT or contraction by phenylephrine that was independent of nitric oxide synthase, cyclooxygenase, endothelium and potassium channels iberiotoxin and apamin sensitive. The Ca2+ channel inhibitor, nimodipine, significantly blocked MT and also the contraction to phenylephrine and KCl. Under these conditions, H2O2 had no effect on RA diameter. Under KCl, the same concentration of H2O2 induced a potent vasoconstriction. This contraction involved p38 mitogen-activated protein-kinase activation but not ERK1/2. CONCLUSIONS These findings provide the first evidence showing that the same and low concentrations of H2O2 can act as a relaxing factor but also as a vasoconstrictor under conditions in which hyperpolarization is compromised.
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Affiliation(s)
- Pamela A Lucchesi
- University of Alabama at Birmingham, Department of Physiology and Biophysics, Birmingham, Alabama, USA
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18
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Sahin AS, Atalik KE, Sahin TK, Doğan N. Cooling and response to hydrogen peroxide in human saphenous vein: role of the endothelium. Fundam Clin Pharmacol 2005; 19:341-6. [PMID: 15910658 DOI: 10.1111/j.1472-8206.2005.00330.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the present work we studied the responses of human saphenous vein to H2O2 and effects of moderate cooling on these responses with analysis of the role of endothelium. H2O2 (10(-7)-10(-2) M) induced concentration-dependent contraction in the intact human saphenous vein strips at both temperatures. At 28 degrees C, the maximal contraction induced by H2O2 was significantly lower than that at 37 degrees C. Compared with intact strips, the sensitivity and the maximal contraction to H2O2 were significantly enhanced in endothelium-denuded strips at 37 and 28 degrees C. However, pD2 values and maximal contractions were not significantly different in endothelium-denuded strips at different temperatures. Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME) increased significantly the maximal contraction and sensitivity to H2O2 at 37 and 28 degrees C. The contractions increased by L-NAME were restored by the pre-incubation of l-arginine (10(-3) M) at every temperature studied. The contractile responses of intact human saphenous veins to H2O2 were reduced significantly by 10(-5) M indomethacin at both temperatures. Our results suggest that H2O2-induced contraction of human saphenous vein are mediated by its direct effect on the smooth muscle and by the generation of products of the cyclooxygenase pathway from the endothelium. Signalling pathways of these contractile effects are the same at 37 and 28 degrees C. Under normal temperature conditions, the contraction to H2O2 is possibly modulated by endothelial nitric oxide. Cooling reduces the contraction to H2O2 by increasing release of nitric oxide.
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Affiliation(s)
- Ayşe Saide Sahin
- Department of Pharmacology, Meram Medicine Faculty, Selçuk University, Konya, Turkey.
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19
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Gluais P, Edwards G, Weston AH, Vanhoutte PM, Félétou M. Hydrogen peroxide and endothelium-dependent hyperpolarization in the guinea-pig carotid artery. Eur J Pharmacol 2005; 513:219-24. [PMID: 15862803 DOI: 10.1016/j.ejphar.2005.02.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 02/14/2005] [Accepted: 02/24/2005] [Indexed: 10/25/2022]
Abstract
This study was designed to determine whether or not endothelium-dependent hyperpolarizations evoked by acetylcholine in the isolated guinea-pig carotid artery involve hydrogen peroxide. Membrane potential was recorded in the vascular smooth muscle cells of that artery. Under control conditions, acetylcholine induced endothelium-dependent hyperpolarization of the vascular smooth muscle cells which was not affected by the presence of catalase, superoxide dismutase or their combination. Neither the superoxide dismutase mimetic, tiron nor the thiol-reducing agent N-acetyl-L-cysteine modified the hyperpolarization evoked by 0.1 microM acetylcholine but each produced a partial and significant inhibition of the hyperpolarization induced by 1 microM acetylcholine. Neither 10 nor 100 microM hydrogen peroxide influenced the resting membrane potential of the smooth muscle cells and the higher concentration did not significantly influence the hyperpolarization elicited by acetylcholine. These data indicate that, in the guinea-pig isolated carotid artery, hydrogen peroxide is unlikely to contribute to the endothelium-dependent hyperpolarization evoked by acetylcholine.
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20
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Sakurai W, Watanabe M, Yamashina A, Konishi M. Effects of hydrogen peroxide on contraction of skinned aorta from guinea pigs. ACTA ACUST UNITED AC 2004; 53:471-4. [PMID: 15038846 DOI: 10.2170/jjphysiol.53.471] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We examined the effects of hydrogen peroxide (H2O2) on the contractile force of cell membrane permeabilized descending thoracic aorta from guinea pigs. H2O2 enhanced generated force in the Ca2+-induced contraction at any given concentration of Ca2+, and maintained force level in the 30 mM Mg2+-induced Ca2+-independent force maintenance. H2O2 seems to directly enhance the cross-bridge interaction of aortic smooth muscles.
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Affiliation(s)
- Wataru Sakurai
- Second Department of Internal Medicine, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-0023 Japan.
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21
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Ellis A, Triggle CR. Endothelium-derived reactive oxygen species: their relationship to endothelium-dependent hyperpolarization and vascular tone. Can J Physiol Pharmacol 2004; 81:1013-28. [PMID: 14719036 DOI: 10.1139/y03-106] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Opinions on the role of reactive oxygen species (ROS) in the vasculature have shifted in recent years, such that they are no longer merely regarded as indicators of cellular damage or byproducts of metabolism--they may also be putative mediators of physiological functions. Hydrogen peroxide (H2O2), in particular, can initiate vascular myocyte proliferation (and, incongruously, apoptosis), hyperplasia, cell adhesion, migration, and the regulation of smooth muscle tone. Endothelial cells express enzymes that produce ROS in response to various stimuli, and H2O2 is a potent relaxant of vascular smooth muscle. H2O2 itself can mediate endothelium-dependent relaxations in some vascular beds. Although nitric oxide (NO) is well recognized as an endothelium-derived dilator, it is also well established, particularly in the microvasculature, that another factor, endothelium-derived hyperpolarizing factor (EDHF), is a significant determinant of vasodilatory tone. This review primarily focuses on the hypothesis that H2O2 is an EDHF in resistance arteries. Putative endothelial sources of H2O2 and the effects of H2O2 on potassium channels, calcium homeostasis, and vascular smooth muscle tone are discussed. Furthermore, given the perception that ROS can more likely elicit cytotoxic effects than perform signalling functions, the arguments for and against H2O2 being an endogenous vasodilator are assessed.
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Affiliation(s)
- Anthie Ellis
- Smooth Muscle Research Group, Faculty of Medicine, University of Calgary, AB, Canada
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22
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Ellis A, Pannirselvam M, Anderson TJ, Triggle CR. Catalase has negligible inhibitory effects on endothelium-dependent relaxations in mouse isolated aorta and small mesenteric artery. Br J Pharmacol 2003; 140:1193-200. [PMID: 14597598 PMCID: PMC1574136 DOI: 10.1038/sj.bjp.0705549] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2003] [Revised: 09/05/2003] [Accepted: 09/23/2003] [Indexed: 11/09/2022] Open
Abstract
1. The current study examined the hypothesis that endothelial production of hydrogen peroxide (H2O2) mediates relaxations to acetylcholine (ACh) in aorta and small mesenteric arteries (SMA) from mice. 2. Relaxations to ACh (0.01-10 microM) and H2O2 (0.1-1000 microM) were produced in aorta and SMA isolated from wild-type C57BL/6 mice and type II diabetic mice (db/db). In SMA, relaxations to ACh were produced in the presence of N omega-nitro-L-arginine methyl ester (100 microM) and indomethacin (Indo, 10 microM). 3. 1-H[1,2,4]oxadiazolo[4,3-]quinoxalin-1-one (10 microM) significantly reduced ACh-induced relaxations in SMA, abolished responses in aorta, but had no effect on relaxations induced by H2O2. Catalase (2500 U ml-1) abolished responses to H2O2, but did not alter relaxations to ACh in the SMA and only caused a small rightward shift in responses to ACh in the aorta. 4. ACh-, but not H2O2-, mediated relaxations were significantly reduced by tetraethylammonium (10 mM), the combination of apamin (1 microM) and charybdotoxin (100 nM), and 25 mm potassium chloride (KCl). Higher KCl (60 mM) abolished relaxations to both ACh and H2O2. Polyethylene glycolated superoxide dismutase (100 U ml-1), the catalase inhibitor 3-amino-1,2,4-triazole (3-AT, 50 mM) and treatment with the copper chelator diethyldithiolcarbamate (3 mM) did not affect relaxations to ACh. 5. H2O2-induced relaxations were endothelium-independent and were not affected by ethylene diamine tetraacetic acid (EDTA 0.067 mM), 4-aminopyridine (1 mM), ouabain (100 microM) and barium (30 microM), 3-AT or Indo. 6. Although the data from this study show that H2O2 dilates vessels, they do not support the notion that H2O2 mediates endothelium-dependent relaxations to ACh in either aorta or SMA from mice.
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MESH Headings
- Acetylcholine/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Aorta, Thoracic/physiopathology
- Apamin/pharmacology
- Cardiovascular Agents/pharmacology
- Catalase/pharmacology
- Charybdotoxin/pharmacology
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/physiopathology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Enzyme Inhibitors/pharmacology
- Hydrogen Peroxide/pharmacology
- Indomethacin/pharmacology
- Male
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Muscle Relaxation/drug effects
- Muscle Relaxation/physiology
- Muscle, Smooth, Vascular/drug effects
- NG-Nitroarginine Methyl Ester/pharmacology
- Potassium Channel Blockers/pharmacology
- Potassium Chloride/pharmacology
- Quinoxalines/pharmacology
- Tetraethylammonium/pharmacology
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Anthie Ellis
- Smooth Muscle Research Group, Faculty of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada T2N 4N1
| | - Malarvannan Pannirselvam
- Smooth Muscle Research Group, Faculty of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada T2N 4N1
| | - Todd J Anderson
- Smooth Muscle Research Group, Faculty of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada T2N 4N1
- Division of Cardiology, Foothills Hospital, Calgary, AB, Canada
| | - Chris R Triggle
- Smooth Muscle Research Group, Faculty of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada T2N 4N1
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Yang M, Yang Y, Zhang S, Kahn AM. Insulin-stimulated hydrogen peroxide increases guanylate cyclase activity in vascular smooth muscle. Hypertension 2003; 42:569-73. [PMID: 12963680 DOI: 10.1161/01.hyp.0000092441.27668.bd] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Insulin resistance is associated with vascular disease. Physiological concentrations of insulin inhibit cultured vascular smooth muscle cell (VSMC) contraction and migration by increasing nitric oxide (NO)-stimulated cGMP accumulation. The failure to do so in insulin-resistant states may aggravate vascular disease. We sought to determine the mechanism of insulin's increase in cGMP accumulation. Isobutylmethylxanthine, an inhibitor of phosphodiesterase activity, inhibited the decline in cGMP levels measured by immunoassay in cGMP-loaded cultured rat aortic VSMCs, but 1 nmol insulin did not. Thus, insulin's increase in cGMP accumulation is due to stimulated production, not inhibited hydrolysis and/or efflux. Insulin, which increases the NADH/NAD+ ratio in these cells, stimulated superoxide anion (O2-) accumulation measured by lucigenin luminescence to 256+/-25% (P<0.05) by a process that was blocked by the NADH oxidase inhibitor diphenyliodonium (DPI) and enhanced by the superoxide dismutase inhibitor diethyldithiocarbonate (DETCA). Insulin also stimulated hydrogen peroxide (H2O2) accumulation measured by horseradish peroxidase/luminol luminescence to 221+/-22% (P<0.05) by a DETCA-sensitive mechanism. H2O2 (100 micromol/L) in the absence of insulin increased NO-stimulated cGMP accumulation to 151+/-11% (P<0.05). Insulin alone increased NO-stimulated cGMP accumulation to 183+/-17% (P<0.05), and this was blocked by either DPI or DETCA. We conclude that insulin increases NADH oxidase-derived O2- production in cultured rat VSMCs. This did not cause the expected scavenging of NO resulting in the reduction of NO-stimulated guanylate cyclase activity, but enough O2- was metabolized to H2O2 to increase overall NO-stimulated cGMP production.
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Affiliation(s)
- Ming Yang
- Division of Renal Diseases and Hypertension, Department of Medicine, The University of Texas Health Science Center, Houston, Tex 77030, USA
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