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NADPH oxidase 4 has a crucial impact on the microcirculation of hypercholesteremic LDL receptor deficient mice. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.3381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Introduction
NADPH oxidase (NOX) 4-generated H2O2 has anti-atherosclerotic properties in conduit arteries like the aorta and carotids. However, the role of NOX4 on vascular function of small resistance arteries and blood pressure in a mouse model of familial hypercholesterolemia is unknown.
Purpose
We evaluated whether NOX4-generated H2O2 might play a role in perivascular adipose tissue of the thoracic aorta (tPVAT) and small resistance arteries on vascular function in a mouse model of familial hypercholesterolemia.
Methods
Aortic segments and mesenteric arteries from 26-week-old Ldlr−/− and Nox4−/− / Ldlr−/− mice were analysed by Mulvany myograph. In addition, vascular contraction and relaxation was analysed in the presence of L-NAME and catalase. Analysis of mRNA expression was performed in murine and human tissue by quantitative real-time PCR. Blood pressure was detected by tail cuff method in conscious, trained mice.
Results
Loss of NOX4 led to severe endothelial dysfunction in mesenteric arteries of Ldlr−/− mice. Blocking of NO synthases with L-NAME led to decreased endothelial relaxation in Ldlr−/− mice at the level of Nox4−/− / Ldlr−/− mice. However, incubation with L-NAME did not worsen the established endothelial dysfunction of the mesenteric arteries from Nox4−/− / Ldlr−/− mice. These results are strikingly different from the aorta, where inhibition of NO synthases led to a similarly impaired endothelial relaxation in both mouse strains. We detected a similar eNOS expression in the aorta of Ldlr−/− and Nox4−/− / Ldlr−/−, but a reduced eNOS expression in the mesenteric arteries of Nox4−/− / Ldlr−/− mice. H2O2 can induce eNOS expression. Therefore, we analysed the vascular function after catalase incubation and again found a significant reduction of endothelial function in the mesenteric arteries of Ldlr−/− mice. Finally, we analysed blood pressure of these mice and did not observe differences in systolic blood pressure, despite significant differences in endothelial function of resistant arteries.
Conclusion
NOX4 protects against severe endothelial dysfunction in the mesenteric artery in a model of hypercholesterolemia.
Funding Acknowledgement
Type of funding sources: Other. Main funding source(s): Ghanaian-German postgraduate training scholarship program (DAAD)
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Abstract
Currently, we are experiencing a true pandemic of a communicable disease by the virus SARS-CoV-2 holding the whole world firmly in its grasp. Amazingly and unfortunately, this virus uses a metabolic and endocrine pathway via ACE2 to enter our cells causing damage and disease. Our international research training programme funded by the German Research Foundation has a clear mission to train the best students wherever they may come from to learn to tackle the enormous challenges of diabetes and its complications for our society. A modern training programme in diabetes and metabolism does not only involve a thorough understanding of classical physiology, biology and clinical diabetology but has to bring together an interdisciplinary team. With the arrival of the coronavirus pandemic, this prestigious and unique metabolic training programme is facing new challenges but also new opportunities. The consortium of the training programme has recognized early on the need for a guidance and for practical recommendations to cope with the COVID-19 pandemic for the community of patients with metabolic disease, obesity and diabetes. This involves the optimal management from surgical obesity programmes to medications and insulin replacement. We also established a global registry analyzing the dimension and role of metabolic disease including new onset diabetes potentially triggered by the virus. We have involved experts of infectious disease and virology to our faculty with this metabolic training programme to offer the full breadth and scope of expertise needed to meet these scientific challenges. We have all learned that this pandemic does not respect or heed any national borders and that we have to work together as a global community. We believe that this transCampus metabolic training programme provides a prime example how an international team of established experts in the field of metabolism can work together with students from all over the world to address a new pandemic.
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P6285Protective effects of exercise on vascular function are mediated by NADPH oxidase 4. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz746.0883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background/Introduction
Physical activity is one of the most potent strategies to prevent endothelial dysfunction. Recent evidence indicates vaso-protective properties of H2O2 produced by main endothelial NADPH oxidase isoform 4 (Nox4) in the vasculature.
Purpose
Therefore, we hypothesized that Nox4 connects physical activity with vaso-protective effects.
Methods and results
Analysis of endothelial function by Mulvany myograph showed endothelial dysfunction in wild-type as well as in Nox4−/− mice after 20 weeks on high-fat diet. Access to voluntary running wheels during high-fat diet prevented endothelial dysfunction in wild-type but not in Nox4−/− mice. Mechanistically, exercise led to increased H2O2 release in the aorta of wild-type mice with increased phosphorylation of eNOS pathway member AKT serine/threonine kinase 1 (Akt1), subsequently. Both effects were diminished in aortas of Nox4−/− mice. Deletion of Nox4 also led to decreased capacity for intracellular calcium release and reduced phenylephrine-mediated contraction, whereas potassium-induced contraction was unaffected. H2O2 scavenger catalase reduced phenylephrine-contraction in wild-type mice. Supplementation of H2O2 increased phenylephrine-induced contraction in Nox4−/− mice. Exercise induced key regulator of mitochondria biogenesis peroxisome proliferative activated receptor gamma, coactivator 1 alpha (Ppargc1a) in wild-type but not Nox4−/− mice. Furthermore, exercise induced citrate synthase activity and reduced mitochondria mass in the absence of Nox4. Thus, Nox4−/− mice became less active and ran less compared with wild-type mice.
Conclusions
Nox4 derived H2O2 plays a key role in exercise-induced adaptations of eNOS and Ppargc1a pathway and intracellular calcium release. Hence, loss of Nox4 diminished physical activity performance and vascular protective effects of exercise.
Acknowledgement/Funding
This work was supported by a research grant of the German Cardiac Society (DGK) (to H.L.) and DFG (Grant MO 1695/4-1 to H.M.).
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P3606Mineralocorticoid receptor antagonist therapy improves vascular function in patients with coronary artery disease. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p3606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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P545Impact of cigarette smoke, next generation tobacco and nicotine products on the cytotoxic, oxidative and pro-inflammatory status of THP-1 cells. Cardiovasc Res 2018. [DOI: 10.1093/cvr/cvy060.401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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P348Optical coherence tomography as a novel method to measure endothelial dysfunction in mice in vivo. Cardiovasc Res 2018. [DOI: 10.1093/cvr/cvy060.261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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P155Cigarette smoke-induced BACH1 regulates the cross talk between NRF2 and AHR through inhibiting microRNA-125b. Cardiovasc Res 2018. [DOI: 10.1093/cvr/cvy060.116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
SummaryThis review focuses on the role of vascular oxidative stress in the development and progression of endothelial dysfunction. We discuss different sources of oxidative stress in the vessel wall, oxidative stress and coagulation, the role of oxidative stress and vascular function in arteries and veins, the flow-dependent regulation of reactive oxygen species, the putative impact of oxidative stress on atherosclerosis, the interaction of angiotensin II, oxidative stress and endothelial dysfunction, and clinical implications.
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P6286Interaction between oxidized LDL, angiotensin II and oxidative stress. Eur Heart J 2017. [DOI: 10.1093/eurheartj/ehx493.p6286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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P3481Inhibition of exosomal and cellular miRNA-125b within the anti-oxidative response to cigarette smoking. Eur Heart J 2017. [DOI: 10.1093/eurheartj/ehx504.p3481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Poster session 3Cell growth, differentiation and stem cells - Heart511The role of the endocannabinoid system in modelling muscular dystrophy cardiac disease with induced pluripotent stem cells.512An emerging role of T lymphocytes in cardiac regenerative processes in heart failure due to dilated cardiomyopathy513Canonical wnt signaling reverses the ‘aged/senescent’ human endogenous cardiac stem cell phenotype514Hippo signalling modulates survival of human induced pluripotent stem cell-derived cardiomyocytes515Biocompatibility of mesenchymal stem cells with a spider silk matrix and its potential use as scaffold for cardiac tissue regeneration516A snapshot of genome-wide transcription in human induced pluripotent stem cell-derived hepatocyte-like cells (iPSC-HLCs)517Can NOS/sGC/cGK1 pathway trigger the differentiation and maturation of mouse embryonic stem cells (ESCs)?518Introduction of external Ik1 to human-induced pluripotent stem cell-derived cardiomyocytes via Ik1-expressing HEK293519Cell therapy of the heart studied using adult myocardial slices in vitro520Enhancement of the paracrine potential of human adipose derived stem cells when cultured as spheroid bodies521Mechanosensitivity of cardiomyocyte progenitor cells: the strain response in 2D and 3D environments522The effect of the vascular-like network on the maturation of the human induced pluripotent stem cell derived cardiomyocytes.Transcriptional control and RNA species - Heart525Gene expression regulation in heart failure: from pathobiology to bioinformatics526Human transcriptome in idiopathic dilated cardiomyopathy - a novel high throughput screening527A high-throghput approach unveils putative miRNA-mediated mitochondria-targeted cardioprotective circuits activated by T3 in the post ischemia reperfusion setting528The effect of uraemia on the expression of miR-212/132 and the calcineurin pathway in the rat heartCytokines and cellular inflammation - Heart531Lack of growth differentiation factor 15 aggravates adverse cardiac remodeling upon pressure-overload in mice532Blocking heteromerization of platelet chemokines ccl5 and cxcl4 reduces inflammation and preserves heart function after myocardial infarction533Is there an association between low-dose aspirin use and clinical outcome in HFPEF? Implications of modulating monocyte function and inflammatory mediator release534N-terminal truncated intracellular matrix metalloproteinase-2 expression in diabetic heart.535Expression of CD39 and CD73 on peripheral T-cell subsets in calcific aortic stenosis536Mast cells in the atrial myocardium of patients with atrial fibrillation: a comparison with patients in sinus rhythm539Characteristics of the inflammatory response in patients with coronary artery disease and arterial hypertension540Pro-inflammatory cytokines as cardiovascular events predictors in rheumatoid arthritis and asymptomatic atherosclerosis541Characterization of FVB/N murinic bone marrow-derived macrophage polarization into M1 and M2 phenotypes542The biological expression and thoracic anterior pain syndromeSignal transduction - Heart545The association of heat shock protein 90 and TGFbeta receptor I is involved in collagen production during cardiac remodelling in aortic-banded mice546Loss of the inhibitory GalphaO protein in the rostral ventrolateral medulla of the brainstem leads to abnormalities in cardiovascular reflexes and altered ventricular excitablitiy547Selenoprotein P regulates pressure overload-induced cardiac remodeling548Study of adenylyl cyclase activity in erythrocyte membranes in patients with chronic heart failure549Direct thrombin inhibitors inhibit atrial myocardium hypertrophy in a rat model of heart failure and atrial remodeling550Tissue factor / FVIIa transactivates the IGF-1R by a Src-dependent phosphorylation of caveolin-1551Notch signaling is differently altered in endothelial and smooth muscle cells of ascending aortic aneurysm patients552Frizzled 5 expression is essential for endothelial proliferation and migration553Modulation of vascular function and ROS production by novel synthetic benzopyran analogues in diabetes mellitusExtracellular matrix and fibrosis - Heart556Cardiac fibroblasts as inflammatory supporter cells trigger cardiac inflammation in heart failure557A role for galectin-3 in calcific aortic valve stenosis558Omega-3 polyunsaturated fatty acids- can they decrease risk for ventricular fibrillation?559Serum levels of elastin derived peptides and circulating elastin-antielastin immune complexes in sera of patients with coronary artery disease560Endocardial fibroelastosis is secondary to hemodynamic alterations in the chick model of hypoplastic left heart syndrome561Dynamics of serum levels of matrix metalloproteinases in primary anterior STEMI patients564Deletion of the alpha-7 nicotinic acetylcholine receptor changes the vascular remodeling induced by transverse aortic constriction in mice.565Extracellular matrix remodelling in response to venous hypertension: proteomics of human varicose veinsIon channels, ion exchangers and cellular electrophysiology - Heart568Microtubule-associated protein RP/EB family member 1 modulates sodium channel trafficking and cardiac conduction569Investigation of electrophysiological abnormalities in a rabbit athlete's heart model570Upregulation of expression of multiple genes in the atrioventricular node of streptozotocin-induced diabetic rat571miR-1 as a regulator of sinoatrial rhythm in endurance training adaptation572Selective sodium-calcium exchanger inhibition reduces myocardial dysfunction associated with hypokalaemia and ventricular fibrillation573Effect of racemic and levo-methadone on action potential of human ventricular cardiomyocytes574Acute temperature effects on the chick embryonic heart functionVasculogenesis, angiogenesis and arteriogenesis577Clinical improvement and enhanced collateral vessel growth after monocyte transplantation in mice578The role of HIF-1 alpha, VEGF and obstructive sleep apnoea in the development of coronary collateral circulation579Initiating cardiac repair with a trans-coronary sinus catheter intervention in an ischemia/reperfusion porcine animal model580Early adaptation of pre-existing collaterals after acute arteriolar and venular microocclusion: an in vivo study in chick chorioallantoic membraneEndothelium583EDH-type responses to the activator of potassium KCa2.3 and KCa3.1 channels SKA-31 in the small mesenteric artery from spontaneously hypertensive rats584The peculiarities of endothelial dysfunction in patients with chronic renocardial syndrome585Endothelial dysfunction, atherosclerosis of the carotid arteries and level of leptin in patient with coronary heart disease in combination with hepatic steatosis depend from body mass index.586Role of non-coding RNAs in thoracic aortic aneurysm associated with bicuspid aortic valve587Cigarette smoke extract abrogates atheroprotective effects of high laminar flow on endothelial function588The prognostic value of anti-connective tissue antibodies in coronary heart disease and asymptomatic atherosclerosis589Novel potential properties of bioactive peptides from spanish dry-cured ham on the endothelium.Lipids592Intermediate density lipoprotein is associated with monocyte subset distribution in patients with stable atherosclerosis593The characteristics of dyslipidemia in rheumatoid arthritisAtherosclerosis596Macrophages differentiated in vitro are heterogeneous: morphological and functional profile in patients with coronary artery disease597Palmitoylethanolamide promotes anti-inflammatory phenotype of macrophages and attenuates plaque formation in ApoE-/- mice598Amiodarone versus esmolol in the perioperative period: an in vitro study of coronary artery bypass grafts599BMPRII signaling of fibrocytes, a mesenchymal progenitor cell population, is increased in STEMI and dyslipidemia600The characteristics of atherogenesis and systemic inflammation in rheumatoid arthritis601Role of adenosine-to-inosine RNA editing in human atherosclerosis602Presence of bacterial DNA in thrombus aspirates of patients with myocardial infarction603Novel E-selectin binding polymers reduce atherosclerotic lesions in ApoE(-/-) mice604Differential expression of the plasminogen receptor Plg-RKT in monocyte and macrophage subsets - possible functional consequences in atherogenesis605Apelin-13 treatment enhances the stability of atherosclerotic plaques606Mast cells are increased in the media of coronary lesions in patients with myocardial infarction and favor atherosclerotic plaque instability607Association of neutrophil to lymphocyte ratio with presence of isolated coronary artery ectasiaCalcium fluxes and excitation-contraction coupling610The coxsackie- and adenovirus receptor (CAR) regulates calcium homeostasis in the developing heart611HMW-AGEs application acutely reduces ICaL in adult cardiomyocytes612Measuring electrical conductibility of cardiac T-tubular systems613Postnatal development of cardiac excitation-contraction coupling in rats614Role of altered Ca2+ homeostasis during adverse cardiac remodeling after ischemia/reperfusion615Experimental study of sarcoplasmic reticulum dysfunction and energetic metabolism in failing myocardium associated with diabetes mellitusHibernation, stunning and preconditioning618Volatile anesthetic preconditioning attenuates ischemic-reperfusion injury in type II diabetic patients undergoing on-pump heart surgery619The effect of early and delayed phase of remote ischemic preconditioning on ischemia-reperfusion injury in the isolated hearts of healthy and diabetic rats620Post-conditioning with 1668-thioate leads to attenuation of the inflammatory response and remodeling with less fibrosis and better left ventricular function in a murine model of myocardial infarction621Maturation-related changes in response to ischemia-reperfusion injury and in effects of classical ischemic preconditioning and remote preconditioningMitochondria and energetics624Phase changes in myocardial mitochondrial respiration caused by hypoxic preconditioning or periodic hypoxic training625Desmin mutations depress mitochondrial metabolism626Methylene blue modulates mitochondrial function and monoamine oxidases-related ROS production in diabetic rat hearts627Doxorubicin modulates the real-time oxygen consumption rate of freshly isolated adult rat and human ventricular cardiomyocytesCardiomyopathies and fibrosis630Effects of genetic or pharmacologic inhibition of the ubiquitin/proteasome system on myocardial proteostasis and cardiac function631Suppression of Wnt signalling in a desmoglein-2 transgenic mouse model for arrhythmogenic cardiomyopathy632Cold-induced cardiac hypertrophy is reversed after thermo-neutral deacclimatization633CD45 is a sensitive marker to diagnose lymphocytic myocarditis in endomyocardial biopsies of living patients and in autopsies634Atrial epicardial adipose tissue derives from epicardial progenitors635Caloric restriction ameliorates cardiac function, sympathetic cardiac innervation and beta-adrenergic receptor signaling in an experimental model of post-ischemic heart failure636High fat diet improves cardiac remodelling and function after extensive myocardial infarction in mice637Epigenetic therapy reduces cardiac hypertrophy in murine models of heart failure638Imbalance of the VHL/HIF signaling in WT1+ Epicardial Progenitors results in coronary vascular defects, fibrosis and cardiac hypertrophy639Diastolic dysfunction is the first stage of the developing heart failure640Colchicine aggravates coxsackievirus B3 infection in miceArterial and pulmonary hypertension642Osteopontin as a marker of pulmonary hypertension in patients with coronary heart disease combined with chronic obstructive pulmonary disease643Myocardial dynamic stiffness is increased in experimental pulmonary hypertension partly due to incomplete relaxation644Hypotensive effect of quercetin is possibly mediated by down-regulation of immunotroteasome subunits in aorta of spontaneously hypertensive rats645Urocortin-2 improves right ventricular function and attenuates experimental pulmonary arterial hypertension646A preclinical evaluation of the anti-hypertensive properties of an aqueous extract of Agathosma (Buchu)Biomarkers648The adiponectin level in hypertensive females with rheumatoid arthritis and its relationship with subclinical atherosclerosis649Markers for identification of renal dysfunction in the patients with chronic heart failure650cardio-hepatic syndromes in chronic heart failure: North Africa profile651To study other biomarkers that assess during myocardial infarction652Interconnections of apelin levels with parameters of lipid metabolism in hypertension patients653Plasma proteomics in hypertension: prediction and follow-up of albuminuria during chronic renin-angiotensin system suppression654Soluble RAGE levels in plasma of patients with cerebrovascular events. Cardiovasc Res 2016. [DOI: 10.1093/cvr/cvw150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
Obesity is a well-known risk factor of atherosclerosis and heart failure. In the human heart, a local endothelin system containing prepro-endothelin-1, endothelin-converting enzyme-1, and endothelin receptors A and B has been described. The endothelin system is activated in heart failure; however, the impact of obesity on the cardiac endothelin system is unknown. In this study, 18-week-old male C57BL/6 mice fed either a control diet or a high-fat diet for 10 weeks were analyzed. High-fat diet significantly increased the body weight of the animals and augmented low-density lipoprotein, high-density lipoprotein, and cholesterol plasma levels, compared to control. The animal groups showed no significant differences in left ventricular size or function (heart rate, ejection fraction, fractional shortening, left ventricular posterior wall thickness, cardiac output) after control or high-fat diet. We did not observe signs of cardiac hypertrophy or changes in markers of cardiac fibrosis in these heart samples. The cardiac expression of prepro-endothelin-1 mRNA, endothelin-converting enzyme-1 mRNA, and protein and endothelin receptors A and B mRNA was increased in 18-week-old obese C57BL/6 mice compared to animals with normal weight (p<0.05 vs. control). Furthermore, endothelin-1 plasma levels showed an increasing trend. In conclusion, an increased expression of genes of the endothelin system was observed in the hearts of 18-week-old mice after high-fat diet, possibly contributing to later cardiovascular complications of obesity.
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Impact of mineralocorticoid receptor blockade on vascular function in atherosclerotic mouse models under high-fat diet. Atherosclerosis 2014. [DOI: 10.1016/j.atherosclerosis.2014.05.434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Local hemodynamic forces and aqueous cigarette smoke extract affect development of endothelial dysfunction. Atherosclerosis 2014. [DOI: 10.1016/j.atherosclerosis.2014.05.323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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15
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Influence of a mineralocorticoid receptor blockade on vascular function in atherosclerotic mouse models under high-fat diet. Exp Clin Endocrinol Diabetes 2014. [DOI: 10.1055/s-0034-1371981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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ERK1/2 MAPKs and Wnt Signaling Pathways are Independently Involved in Adipocytokine-Mediated Aldosterone Secretion. Exp Clin Endocrinol Diabetes 2011; 119:644-8. [DOI: 10.1055/s-0031-1284367] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AbstractObesity is one major risk factor for the development of arterial hypertension, and the development of obesity-related hypertension has been associated with increased plasma aldosterone levels. Our previous work shows a direct stimulatory effect of adipokines on aldosterone secretion from human adrenocortical cells, mediated via ERK1/2-dependent upregulation of steroid acute regulatory protein (StAR) activity. Recent evidence also indicates the involvement of the Wnt-signaling pathway in fat cell-mediated aldosterone secretion. Wnt-signaling molecules are secreted by adipocytes and regulate the activity of SF-1, a key transcription factor in adrenal steroidogenesis. The goal of this study was to investigate the cellular mechanisms of adipocyte-induced aldosterone secretion in detail, and to evaluate effects and possible interactions of the ERK1/2 MAPK- and the Wnt-signaling pathways on adipocyte-induced adrenocortical aldosterone secretion. Our results show that, similar to adipocyte-conditioned medium (ACM), β-catenin, which is an intracellular mediator of canonical Wnt-signaling, induced StAR promotor activity in human NCI-H295R adrenocortical cells, and ACM-induced StAR promotor activity depended on intact SF-1 binding sites. Wnt antagonist sFRP-1 inhibited adipokine-mediated StAR activity, but did not affect ERK1/2 MAPK activation. Accordingly, Wnt did not stimulate ERK1/2 phosphorylation in adrenocortical cells, indicating that ERK1/2 MAPK and Wnt signaling pathways are independently involved in adipocyte-mediated aldosterone secretion.
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Saturday, 17 July 2010. Cardiovasc Res 2010. [DOI: 10.1093/cvr/cvq174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sunday, 18 July 2010. Cardiovasc Res 2010. [DOI: 10.1093/cvr/cvq176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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22
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[LOX-1 receptor as a novel target in endothelial dysfunction and atherosclerosis]. Dtsch Med Wochenschr 2010; 135:308-12. [PMID: 20146162 DOI: 10.1055/s-0029-1244854] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Atherosclerosis with its complications like heart attack and stroke, is the most frequent cause of death in the industrialized countries. Oxidized low-density lipoproteins (LDL) play a major role in the pathogenesis of atherosclerosis. Inhibition of cholesterol synthesis by statins has several protective effects but is not sufficient to prevent the uptake of oxidized LDL and the development of atherosclerotic plaques. For this reason a selective pharmacological inhibition of the uptake of oxidized LDL (oxLDL) in endothelial cells is an interesting therapeutic approach. An important novel target molecule is the endothelial lectin-like oxLDL receptor LOX-1. This receptor is able to take up both minimally and highly oxidized LDL. In addition it mediates endothelial phagocytosis of aged and apoptotic cells and plays a role in thrombocyte adhesion and in the interaction between bacterial proteins and endothelial cells in sepsis. LOX-1 is induced by proinflammatory cytokines, oxLDL, angiotensin II, endothelin-1 and arterial hypertension. LOX-1 increases endothelial dysfunction and atherosclerosis by endothelial uptake of oxLDL. This is the reason why LOX-1 has been considered as a novel link between hypertension and atherosclerosis. Transgenic overexpression of the LOX-1 receptor and high-fat diet induces intramyocardial vascular disease and endothelial dysfunction in resistance arteries. In contrast, genetic deletion of the LOX-1 gene reduces the development of atherosclerotic plaques. In the clinical context LOX-1 has been detected in the early phase of endothelial dysfunction and atherosclerosis in arteries of patients with coronary heart disease. Several novel data support a role of LOX-1 in the endothelial dysfunction in diabetic vascular and renal disease, hypercholesterolemia, obesity and preeclampsia. This makes the LOX-1 receptor a novel and interesting target molecule in endothelial dysfunction and atherosclerosis.
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Abstract
Diabetes mellitus is an important risk factor for cardiovascular diseases. Clinical evidence supports a link between hyperglycemia, endothelial dysfunction, and vascular disorders. However, the precise molecular mechanisms causing endothelial dysfunction in diabetic patients remain unclear. An interesting novel mediator could be chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII), which plays an essential role in glucose metabolism. COUP-TFII is known to be expressed in venous endothelial cells. In this study, we show COUP-TFII expression in human umbilical vein endothelial cells (HUVECs) and human coronary artery endothelial cells. HUVECs express glucose transporters 1, 3, 6, and 10, and the insulin receptor. Insulin in combination with glucose activates protein kinase B (PKB or Akt) phosphorylation via phosphoinositide 3-kinase (PI3-kinase). Short-term (60-240 min) stimulation of HUVECs with high glucose increased COUP-TFII expression independent of insulin. Long-term (48 h) stimulation of HUVECs with high glucose augmented expression of the insulin receptor and E-selectin, but downregulated COUP-TFII protein expression. Downregulation of COUP-TFII by shRNA leads to downregulation of E-selectin and upregulation of eNOS and glucose transporters. Our data suggest that COUP-TFII is regulated by glucose in a time- and dose-dependent manner in endothelial cells. COUP-TFII might affect endothelial function in a diabetic background.
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Abstract
In this study, we demonstrate the application of optical coherence tomography (OCT) as a contactless imaging technique to analyze vasodynamics in small blood vessels in vivo. The transluminal OCT imaging of vessels avoids micro traumata in the endothelium and circumvents surgical intervention. It can be performed in the intact perfused vessel and provides a new method to measure vascular function and dynamics in vivo. The resolution of 10 mum and the velocity of image acquisition are adequate to detect differences in the inner diameter, the maximal velocity, or the time to half-maximal diameter change of small vessels. We applied this new technology to study the vascular dynamics in small vessels of 6- and 20-week-old C57BL/6 mice in vivo. In addition, we determined by this technique the impact of a high-fat diet for 14 weeks on vascular function in 20-week-old animals. The diameter of the saphenous artery was increased under resting conditions, after vasoconstriction and after vasodilatation in 20-week-old animals on normal chow and high-fat diet, compared to 6-week-old animals. High-fat diet caused a significantly impaired vasoconstriction in the saphenous artery. The maximal velocity of diameter changes of the saphenous artery was determined by time-resolved OCT imaging. A significant reduction of this parameter was found during vasoconstriction in 20-week-old mice on high-fat diet, compared to 6-week-old animals. In conclusion, transluminal optical coherence tomography imaging is a novel and useful technique to analyze the impaired vasodynamics of small arteries in response to high-fat diet in vivo.
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Endotheliale Dysfunktion und Atherosklerose. Z Geburtshilfe Neonatol 2009. [DOI: 10.1055/s-0029-1216310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
The regulation of endothelial function plays an important role in the development and progression of metabolic and cardiovascular diseases. A critical determinant of endothelial function is the balance between nitric oxide and reactive oxygen species. Endothelium-derived NO availability can be limited by enhanced formation of reactive oxygen species. Major sources of reactive oxygen species in the vessel wall are NAD(P)H oxidase complexes. This review summarizes the impact of vascular NAD(P)H oxidase-derived reactive oxygen species on atherosclerosis and endothelial dysfunction. Changes in NAD(P)H oxidase expression and activity have clinical implications. Mutations in NAD(P)H oxidase subunits can lead to impaired oxidative burst in leukocytes and chronic granulomatous disease. In contrast, normalization of increased expression and activity of NAD(P)H oxidase in endothelial dysfunction and vascular disorders can be considered as a novel therapeutic strategy in the treatment of cardiovascular diseases.
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Expression of human endothelin-converting enzyme isoforms: role of angiotensin II. Can J Physiol Pharmacol 2008; 86:299-309. [PMID: 18516092 DOI: 10.1139/y08-023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A key step in endothelin-1 (ET-1) synthesis is the proteolytic cleavage of big ET-1 by the endothelin-converting enzyme-1 (ECE-1). Four alternatively spliced isoforms, ECE-1a to ECE-1d, have been discovered; however, regulation of the expression of specific ECE-1 isoforms is not well understood. Therefore, we stimulated primary human umbilical vein endothelial cells (HUVECs) with angiotensin II (Ang II). Furthermore, expression of ECE-1 isoforms was determined in internal mammary arteries of patients undergoing coronary artery bypass grafting surgery. Patients had received one of 4 therapies: angiotensin-converting enzyme inhibitors (ACE-I), Ang II type 1 receptor blockers (ARB), HMG-CoA reductase inhibitors (statins), and a control group that had received neither ACE-I, ARB (that is, treatment not interfering in the renin-angiotensin system), nor statins. Under control conditions, ECE-1a is the dominant isoform in HUVECs (4.5+/-2.8 amol/microg RNA), followed by ECE-1c (2.7+/-1.0 amol/microg), ECE-1d (0.49+/-0.17 amol/microg), and ECE-1b (0.17+/-0.04 amol/microg). Stimulation with Ang II did not change the ECE-1 expression pattern or the ET-1 release. We found that ECE-1 mRNA expression was higher in patients treated with statins than in patients treated with ARB therapy (5.8+/-0.76 RU versus 3.0+/-0.4 RU), mainly attributed to ECE-1a. In addition, ECE-1a mRNA expression was higher in patients receiving ACE-I therapy than in patients receiving ARB therapy (1.68+/-0.27 RU versus 0.83+/-0.07 RU). We conclude that ECE-1a is the major ECE-1 isoform in primary human endothelial cells. Its expression in internal mammary arteries can be regulated by statin therapy and differs between patients with ACE-I and ARB therapy.
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Endothelin receptor B-mediated induction of c-jun and AP-1 in response to shear stress in human endothelial cellsThis article is one of a selection of papers published in the special issue (part 2 of 2) on Forefronts in Endothelin. Can J Physiol Pharmacol 2008; 86:499-504. [DOI: 10.1139/y08-026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In vivo, endothelial cells are constantly exposed to shear stress by flowing blood. Short-term exposure of endothelial cells to shear stress has been shown to induce endothelin-1 release. It is currently unknown, however, whether this shear stress-dependent endothelin-1 release affects the expression and activity of transcription factors. In this study, primary cultures of human endothelial cells from the umbilical vein were exposed to laminar shear stress in a cone-and-plate viscometer. Laminar shear stress for 30 min induced a 2-fold increase in mRNA expression of c-jun , but not c-fos, in human endothelial cells. Blockade of endothelin receptor subtype B (ETB) with BQ788 prevented this shear stress-dependent induction of c-jun expression. The induction of c-jun by shear stress involved protein kinase C and endothelial NO synthase. In addition, exposure of endothelial cells to arterial laminar shear stress for 1 h increased the binding of transcription factor AP-1 to its consensus sequence by 1.7-fold in electrophoretic mobility shift assays. This induction was also mediated by an ETB-dependent pathway. Supershift analysis supports an AP-1 complex containing c-jun, but not c-fos, in human endothelial cells. In conclusion, our data suggest endothelin-1-mediated induction of c-jun expression and activation of AP-1 (possibly as a c-jun homodimer) by laminar shear stress in human endothelial cells.
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Abstract
Increased levels of low-density lipoproteins are well-established risk factors of endothelial dysfunction and the metabolic syndrome. In this study, we evaluated the effect of native low-density lipoprotein (nLDL) and oxidized LDL (oxLDL) on the expression of genes of the renin-angiotensin system (angiotensin-converting enzyme, ACE; angiotensin II type 1 receptor, AT(1)) and their receptors (low-density lipoprotein receptor: LDLR; lectin-like oxLDL receptor: LOX-1; toll-like receptor 4: TLR4) in primary cultures of human umbilical vein endothelial cells. ACE and AT(1) expressions were significantly increased after stimulation with nLDL and oxLDL. OxLDL receptor LOX-1 showed a maximum induction after 7 hours. Increased LOX-1 protein expression in response to oxLDL could be blocked by a LOX-1-specific antibody. TLR4 expression was increased by nLDL and oxLDL as well. We conclude that LDL and oxLDL can activate the renin-angiotensin system and their receptors LDLR, LOX-1, and TLR4 in human endothelial cells. These data suggest a novel link between hypercholesterolemia and hypertension in patients with the metabolic syndrome.
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MESH Headings
- Analysis of Variance
- Cells, Cultured
- Endothelial Cells/metabolism
- Gene Expression Regulation/physiology
- Humans
- Hypercholesterolemia/metabolism
- Hypertension/metabolism
- Lipoproteins, LDL/metabolism
- Metabolic Syndrome/metabolism
- Peptidyl-Dipeptidase A/genetics
- Peptidyl-Dipeptidase A/metabolism
- RNA, Messenger/analysis
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Receptors, LDL/genetics
- Receptors, LDL/metabolism
- Renin-Angiotensin System/genetics
- Renin-Angiotensin System/physiology
- Scavenger Receptors, Class E/genetics
- Scavenger Receptors, Class E/metabolism
- Statistics, Nonparametric
- Toll-Like Receptor 4/genetics
- Toll-Like Receptor 4/metabolism
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Pam3CSK4 and LTA-TLRs ligands associated with microdomains induce IL8 production in human adrenocortical cancer cells. Horm Metab Res 2007; 39:457-60. [PMID: 17578764 DOI: 10.1055/s-2007-980189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Bacterially derived ligands, Pam3CSK4 and LPS, can directly impact adrenal glands steroidogenesis through microdomain-related TLR1/2 and 4, respectively, and indirectly via immune cell-derived cytokines. The bilateral immunoadrenal relationship plays an important role in the proper functioning of both systems. CXC chemokine-dependent immune cell infiltration into adrenocortical carcinomas (ACC), which correlates with poor prognosis, is a common phenomenon. Recently, IL8 was identified in ACC and NCI-H295R cells, and was found to contribute to ACC tumour growth. The aim of this study was to clarify the role of different TLR ligands in IL8 production in NCI-H295R cells. This is the first study to demonstrate the expression of several TLRs including TLR1, 3, 6, 7 and 9 in human adrenocortical cells by using the RT-PCR approach. Only stimulation with TLR1/6 together with TLR2 ligands resulted in IL8 peptide and mRNA induction in a dose and time-dependent manner. Our data suggest that gram-positive bacteria-related TLR1/2/6 ligands might contribute to adrenal gland tumorigenesis via IL8 production.
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31
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Oxidative stress and endothelial dysfunction. Hamostaseologie 2007; 27:5-12. [PMID: 17279271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
This review focuses on the role of vascular oxidative stress in the development and progression of endothelial dysfunction. We discuss different sources of oxidative stress in the vessel wall, oxidative stress and coagulation, the role of oxidative stress and vascular function in arteries and veins, the flow-dependent regulation of reactive oxygen species, the putative impact of oxidative stress on atherosclerosis, the interaction of angiotensin II, oxidative stress and endothelial dysfunction, and clinical implications.
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Increased cardiac endothelial nitric oxide synthase expression in patients taking angiotensin-converting enzyme inhibitor therapy. Eur J Clin Invest 2006; 36:705-12. [PMID: 16968466 DOI: 10.1111/j.1365-2362.2006.01715.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND The efficacy of angiotensin-converting enzyme (ACE) inhibitors has been demonstrated in large clinical trials, but knowledge of the underlying mechanisms remains incomplete. Therefore, this study investigated the impact of ACE inhibitor therapy on cardiac nitric oxide (NO) synthases in patients with coronary artery disease (CAD) or heart failure. PATIENTS AND METHODS The mRNA expression was quantified by standard calibrated competitive RT-PCR, protein expression by Western blotting and NOS activity by monitoring the conversion of [3H]arginine to [3H]citrulline during enzymatic formation of NO in tissue homogenates of myocardium of patients with, or without, ACE inhibitor treatment before elective coronary artery bypass grafting or heart transplantation. RESULTS The mRNA expression (amol microg(-1) RNA) of endothelial NO synthase (eNOS) was higher (22.5 +/- 4.8, n = 23) in the atrial myocardium of patients taking ACE inhibitor treatment, before elective coronary artery bypass grafting, compared with patients not taking this therapy (8.9 +/- 0.7, n = 33, P < 0.0001). The ACE inhibitor therapy increased eNOS protein expression from [(9 +/- 0.7) relative units (RUs) to (12 +/- 0.9) RUs, P < 0.05, respectively] and cardiac NOS activity from 17.6 +/- 1.3 to 23.7 +/- 1.1 pmol mg protein(-1) min(-1) (P < 0.001, respectively). Inducible and neuronal NO synthase expression was not changed by the ACE inhibition. A similar up-regulation of eNOS by ACE inhibition was found in the left ventricles of patients with heart failure. The augmented endothelial NOS expression and activity was not the result of differences in clinical characteristics and concomitant therapy between the patient groups. CONCLUSION Increased eNOS expression and activity might contribute to the beneficial effects of ACE inhibitor therapy in the treatment of CAD and heart failure.
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Age-dependent depression in circulating endothelial progenitor cells in patients under coronary artery bypass grafting. Thorac Cardiovasc Surg 2004. [DOI: 10.1055/s-2004-816608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Induction of NAD(P)H oxidase by oxidized low-density lipoprotein in human endothelial cells: antioxidative potential of hydroxymethylglutaryl coenzyme A reductase inhibitor therapy. Circulation 2001; 104:1767-72. [PMID: 11591612 DOI: 10.1161/hc4001.097056] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Elevated oxidative stress and superoxide anion formation in vascular cells could promote conversion of LDL to atherogenic oxidized LDL (oxLDL), contributing to endothelial dysfunction and atherosclerosis. As a major source of vascular superoxide anion formation, an endothelial NAD(P)H oxidase, similar to the leukocyte enzyme, has been identified. METHODS AND RESULTS To elucidate functional differences between NAD(P)H oxidases of endothelial cells and leukocytes, DNA sequences of endothelial NAD(P)H oxidase subunits were determined. Gp91phox cDNA sequence showed no difference between the 2 cell types. Endothelial p67phox cDNA sequence revealed 2 known polymorphisms, which do not affect NAD(P)H oxidase function. Next, we analyzed relative mRNA expression of NAD(P)H subunits in human umbilical vein endothelial cells (HUVECs) and leukocytes using a common cRNA standard in competitive reverse transcription-polymerase chain reaction. NAD(P)H oxidase subunits p22phox and p47phox are expressed at a similar level in both cell types, whereas p67phox (2.5%) and gp91phox (1.1%) are expressed at a much lower level in endothelial cells than in leukocytes. Differences of gp91phox expression in leukocytes and HUVECs correlate with differences in superoxide release. Gp91phox mRNA and endothelial superoxide anion formation are induced in response to oxLDL in HUVECs. Furthermore, a lower gp91phox mRNA expression was found in internal mammary artery biopsy samples of patients with coronary artery disease treated with HMG-CoA reductase inhibitors before coronary bypass surgery. CONCLUSIONS We conclude that oxLDL induces proatherosclerotic NAD(P)H oxidase expression and superoxide anion formation in human endothelial cells and an antioxidative potential of HMG-CoA reductase inhibition via reduction of vascular NAD(P)H oxidase expression.
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Upregulation of vascular NAD(P)H oxidase subunit gp91phox and impairment of the nitric oxide signal transduction pathway in hypertension. Biochem Biophys Res Commun 2001; 285:1130-5. [PMID: 11478771 DOI: 10.1006/bbrc.2001.5312] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study we analyzed the role of vascular NAD(P)H oxidase in the generation of O(2)(-) and the endothelial impairment of NO signal transduction pathway in hypertension. In aortic rings of 15-month-old stroke-prone spontaneously hypertensive rats (SHR15) we found a 10-fold increased expression of NAD(P)H oxidase subunit gp91phox mRNA associated with a 3-fold increased production of O(2)(-) compared to age-matched Wistar rats (WIS15). Vasorelaxation studies in aortas of SHR15 showed a strongly diminished response to acetylcholine, NO-donor S-nitroso-N-acetyl-d,l-penicillamine, and organic nitrate glyceryl trinitrate compared to WIS15. Soluble guanylate cyclase (sGC) activity and sGC beta(1)-subunit protein expression was downregulated in aortas and lungs of SHR15. These data suggest an upregulation of vascular NAD(P)H oxidase and an impairment of the NO signal transduction pathway in hypertension.
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Induction of the oxLDL receptor LOX-1 by endothelin-1 in human endothelial cells. Biochem Biophys Res Commun 2001; 284:961-5. [PMID: 11409887 DOI: 10.1006/bbrc.2001.5044] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study, we analyzed the effect of endothelin-1 (ET-1) on expression of the lectin-like oxidized low-density lipoprotein (oxLDL) receptor-1 LOX-1 and on oxLDL uptake in primary cultures of human umbilical vein endothelial cells (HUVEC). LOX-1 mRNA was quantified by standard-calibrated competitive RT-PCR, LOX-1 protein expression by Western analysis and endothelial oxLDL uptake using DiI-labeled oxLDL. ET-1 induces LOX-1 mRNA expression, reaching its maximum after 1 h (160 +/- 14% of control, 100 nM ET-1, P < 0.05). This increased ET-1-mediated LOX-1 mRNA expression could be inhibited by endothelin receptor B antagonist BQ-788. In addition, ET-1 stimulates LOX-1 protein expression and oxLDL uptake in HUVEC. The augmented oxLDL uptake by ET-1 is mediated by endothelin receptor B, but not by protein kinases. These data support a new pathophysiological mechanism how locally and systemically increased ET-1 levels could promote LOX-1-mediated oxLDL uptake in human endothelial cells and the development and progression of endothelial dysfunction and atherosclerosis.
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MESH Headings
- Biological Transport/drug effects
- Blotting, Western
- Cells, Cultured
- Endothelin Receptor Antagonists
- Endothelin-1/pharmacology
- Endothelium, Vascular/metabolism
- Gene Expression Regulation/drug effects
- Humans
- Kinetics
- Lipoproteins, LDL/metabolism
- Oligopeptides/pharmacology
- Piperidines/pharmacology
- Protein Kinases/metabolism
- RNA, Messenger/genetics
- Receptor, Endothelin B
- Receptors, LDL/analysis
- Receptors, LDL/biosynthesis
- Receptors, LDL/genetics
- Receptors, Oxidized LDL
- Reverse Transcriptase Polymerase Chain Reaction
- Scavenger Receptors, Class E
- Transcription, Genetic/drug effects
- Umbilical Veins
- Up-Regulation/drug effects
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[Reverse remodeling by surgery--fact or fiction?]. ZEITSCHRIFT FUR KARDIOLOGIE 2001; 89 Suppl 7:76-84. [PMID: 11098563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Mortality of chronic heart failure in industrial countries remains unacceptably high despite advances in medical therapy. Heart transplantation, the gold standard in the treatment of end-stage heart failure is reserved for only a few patients because of the shortage of donor hearts. Surgical alternatives to transplantation include dynamic cardiomyoplasty (CMP), mitral valve reconstruction, left ventricular reduction surgery (PLVR) and ventricular assist devices (VAD). Improved survival and objective physiologic improvement have not been documented for CMP in the treatment of dilative cardiomyopathy. Mitral valve reconstruction on the other hand shows promising results. PLVR is an innovative procedure in which the heart is surgically reduced in size and cardiac function is dramatically improved immediately after surgery. The presence of long-term effects is still unknown. VAD have been shown to be extremely effective as a short- and long-term "bridge" to heart transplantation. They are not approved for permanent support. A randomized trial in the U.S. is underway to compare the efficacy of these devices with the efficacy of medical therapy in NYHA functional class IV patients in quality of life, survival and costs.
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Increased expression of endothelin-1 and inducible nitric oxide synthase isoform II in aging arteries in vivo: implications for atherosclerosis. Biochem Biophys Res Commun 2001; 280:908-13. [PMID: 11162610 DOI: 10.1006/bbrc.2000.4180] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We here report that aging increases expression of endothelin-1 and NO synthases in the vasculature and kidney of normotensive rats in vivo. Expression of preproendothelin-1 mRNA was quantified by RT-PCR and in situ hybridization, and endothelin-1 protein was determined by radioimmunoassay/HPLC. Vascular mRNA expression of NO synthase isoforms II and III was analyzed by RT-PCR. In young animals, vascular endothelin-1 protein was differentially expressed (aorta < renal artery < carotid artery) and increased with aging in all vascular beds (P < 0.05). In the intact aorta of aged rats, mRNA expression of preproendothelin-1, "inducible" NO synthase II, and endothelial cell NO synthase III gene was up-regulated (P < 0.05). Moreover, preproendothelin-1 mRNA expression increased in glomeruli and tubulointerstitial cells (P < 0.05). To our knowledge this is the first study demonstrating local vascular up-regulation of the trophic factor endothelin under physiological conditions. Activation of vascular endothelin and NO synthases may be important, pressure-independent factors contributing to structural and functional abnormalities of age-dependent diseases, including atherosclerosis.
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Abstract
The flowing blood generates shear stress at the endothelial cell surface. The endothelial cells modify their phenotype by alterations in gene expression in response to different levels of fluid shear stress. To identify genes involved in this process, human umbilical vein endothelial cells were exposed to laminar shear stress (venous or arterial levels) in a cone-and-plate apparatus for 24 hours. Using the method of RNA arbitrarily primed polymerase chain reaction, we cloned a polymerase chain reaction fragment representing an mRNA species downregulated by arterial compared with venous shear stress (shear stress downregulated gene-1, SSD-1). According to Northern blot analysis, corresponding SSD-1 cDNA clones revealed a similar, time-dependent downregulation after 24 hours of arterial shear stress compared with venous shear stress or static controls. Three SSD-1 mRNA species of 2.8, 4.1, and 4.6 kb were expressed in a tissue-specific manner. The encoded amino acid sequence of the human endothelial SSD-1 isoform (4.1-kb mRNA species) revealed 80.4% identity and 90.9% homology to the bovine ss-tubulin folding cofactor D (tfcD) gene. Downregulation of tfcD mRNA expression by shear stress was defined at the level of transcription by nuclear run-on assays. The tfcD protein was downregulated by arterial shear stress. The shear stress-dependent downregulation of tfcD mRNA and protein was attenuated by the NO synthase inhibitor Nomega-nitro-L-arginine methyl ester. Furthermore, the NO donor DETA-NO downregulated tfcD mRNA. Because tfcD was shown to be a microtubule-destabilizing protein, our data suggest a shear stress-dependent regulation of the microtubular dynamics in human endothelial cells.
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Shear stress-dependent expression of apoptosis-regulating genes in endothelial cells. Biochem Biophys Res Commun 2000; 278:740-6. [PMID: 11095978 DOI: 10.1006/bbrc.2000.3873] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Laminar shear stress exerts potent anti-apoptotic effects. Therefore, we analyzed the influence of laminar shear stress on the expression of apoptosis-regulating genes in human umbilical vein endothelial cells (HUVEC). Application of high levels of laminar shear stress (15 and 30 dyn/cm(2)) decreased the susceptibility of HUVEC to undergo apoptosis, whereas low shear stress (1 dyn/cm(2)) had no effect. These diminished signs of apoptosis were accompanied by a decreased mRNA expression of apoptosis-inducing Fas receptor. Furthermore, mRNA and protein expression of anti-apoptotic, soluble Fas isoform FasExo6Del and anti-apoptotic Bcl-x(L) were induced. Surprisingly, high shear stress also elevated mRNA and protein expression of pro-apoptotic Bak. The shear stress-induced up-regulation of Bcl-x(L) and Bak mRNA can be abrogated by inhibition of the endothelial NO synthase. We propose that altered expression of Bcl-x(L) and the Fas system is involved in the protective effect of laminar shear stress against apoptosis in human endothelial cells.
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Deloading of the left ventricle by ventricular assist device normalizes increased expression of endothelin ET(A) receptors but not endothelin-converting enzyme-1 in patients with end-stage heart failure. Circulation 2000; 102:III188-93. [PMID: 11082385 DOI: 10.1161/01.cir.102.suppl_3.iii-188] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Ventricular assist devices (VAD) are implanted in patients with end-stage heart failure for bridging the time until heart transplantation, resulting in hemodynamic unloading of the failing heart, improved cardiac contractile and mitochondrial function, and reversal of cardiac hypertrophy. It is unknown whether VAD unloading may affect the cardiac endothelin (ET) system, which has been proposed as one of the putative pathomechanisms of heart failure. METHODS AND RESULTS With the use of standard-calibrated, competitive reverse-transcription-polymerase chain reaction mRNA expression of components of the ET system was analyzed in left ventricular myocardium from nonfailing donor hearts, from failing hearts without and with ACE inhibitor therapy, and from patients with end-stage heart failure at the time of VAD implantation and 103+/-15 days after VAD implantation during removal with subsequent heart transplantation. ET receptor A (ET(A)) was markedly upregulated in failing human myocardium. This increased ET(A) expression was not affected by ACE inhibitor treatment but was normalized by VAD unloading. ET(A) expression before or after VAD implantation did not correlate with duration of VAD implantation or suppression of Pro-ANP mRNA. ET(B) mRNA expression was unaffected by heart failure or VAD. In contrast, increased ET-converting enzyme-1 mRNA and ET-1 peptide levels in failing myocardium were partially normalized by ACE inhibition but not by VAD unloading. CONCLUSIONS We conclude that VAD implantation normalizes ET(A) expression in failing human left ventricular myocardium, probably as the result of the beneficial effects of VAD unloading.
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Abstract
Using the orally active endothelin-A- (ET(A)) receptor antagonist LU135252, we determined whether endothelin-1 (ET-1) and/or dietary fat may be involved in angiotensin-converting enzyme (ACE) regulation in vivo. In C57BL6/J mice, renal and pulmonary tissue ACE activity (nmol/l His-Leu/mg protein) was measured and ACE mRNA expression, tissue ET-1 protein content and nitrite/nitrate level were measured in the kidney. Western-type diet increased renal ACE activity by 70% (55 +/- 4 vs 33 +/- 3 nmol/l His-Leu/mg protein, p < 0.05) and increased renal ET-1 levels (267 +/- 19 pg/g vs 190 +/- 18, p < 0.05). Chronic LU135252 treatment completely prevented activation of renal ACE activity (13.3 +/- 0.3 His-Leu/mg protein nmol/l, p < 0.05) independent of ACE mRNA expression or renal ET-1 protein levels. Thus, dietary fat activates renal ACE activity and ET-1 is involved in regulation of tissue ACE activity in vivo independently of ACE mRNA expression.
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The small G-protein Rac mediates depolarization-induced superoxide formation in human endothelial cells. J Biol Chem 2000; 275:18745-50. [PMID: 10764736 DOI: 10.1074/jbc.m000026200] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Superoxide anions impair nitric oxide-mediated responses and are involved in the development of hypertensive vascular hypertrophy. The regulation of their production in the vascular system is, however, poorly understood. We investigated whether changes in membrane potential that occur in hypertensive vessels modulate endothelial superoxide production. In cultured human umbilical vein endothelial cells, changes in membrane potential were induced by high potassium buffer, the non-selective potassium channel blocker tetrabutylammonium chloride (1 mm), and the non-selective cation ionophore gramicidin (1 micrometer). Superoxide formation was significantly elevated to a similar degree by all three treatments (by approximately 60%, n = 23, p < 0.01), whereas hyperpolarization by the K(ATP) channel activator Hoe234 (1 micrometer) significantly decreased superoxide formation. Depolarization also induced an increased tyrosine phosphorylation of several not yet identified proteins (90-110 kDa) and resulted in a significant increase in membrane association of the small G-protein Rac. Accordingly, the Rac inhibitor Clostridium difficile toxin B blocked the effects of depolarization on superoxide formation. The tyrosine kinase inhibitor genistein (30 micrometer, n = 15) abolished depolarization-induced superoxide formation and also prevented depolarization-induced Rac translocation associated with it. It is concluded that depolarization is an important stimulus of endothelial superoxide production, which involves a tyrosine phosphorylation-dependent translocation of the small G-protein Rac.
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Abstract
In this study, the effect of shear stress on the expression of genes of the human endothelin-1 system was examined. Primary cultures of human umbilical vein endothelial cells (HUVEC) were exposed to laminar shear stress of 1, 15 or 30 dyn cm-2 (i.e. 0.1, 1.5 or 3 N m-2) (venous and two different arterial levels of shear stress) in a cone-and-plate viscometer. Laminar shear stress transiently upregulates preproendothelin-1 (ppET-1) mRNA, reaching its maximum after 30 min (approx 1.7-fold increase). In contrast, long-term application of shear stress (24 h) causes downregulation of ppET-1 mRNA in a dose-dependent manner. Arterial levels of shear stress result in downregulation of endothelin-converting enzyme-1 isoform ECE-1a (predominating in HUVEC) to 36.2 +/- 8.5 %, and isoform ECE-1b mRNA to 72.3 +/- 1.9 % of static control level. The endothelin-1 (ET-1) release is downregulated by laminar shear stress in a dose-dependent manner. This downregulation of ppET-1 mRNA and ET-1 release is not affected by inhibition of protein kinase C (PKC), or tyrosine kinase. Inhibition of endothelial NO synthase (L-NAME, 500 microm) prevents downregulation of ppET-1 mRNA by shear stress. In contrast, increasing degrees of long-term shear stress upregulate endothelin receptor type B (ETB) mRNA by a NO- and PKC-, but not tyrosine kinase-dependent mechanism. In conclusion, our data suggest the downregulation of human endothelin synthesis, and an upregulation of the ETB receptor by long-term arterial laminar shear stress. These effects might contribute to the vasoprotective and anti-arteriosclerotic potential of arterial laminar shear stress.
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Abstract
Superoxide anions (O(*-)(2)) induce oxidative stress and reduce endothelial NO availability by peroxynitrite formation. In human endothelial cells gp91(phox) was identified as the limiting subunit of the forming NAD(P)H oxidase. Because endothelin-1 (ET-1) is considered as a pro-atherosclerotic stimulus, we analyzed the effect of ET-1 on gp91(phox) expression and O(*-)(2) generation in primary cultures of human umbilical vein endothelial cells (HUVECs). The gp91(phox) mRNA expression was quantified by standard calibrated competitive reverse transcriptase-polymerase chain reaction. ET-1 induces gp91(phox) mRNA expression in HUVEC (max. after 1 h). The induction of gp91(phox) expression was dose-dependent, reaching its maximum at 10 nmol/L ET-1. The increased gp91(phox) expression is mediated by endothelial receptor type B (ET(B)). Furthermore, ET-1 augments O(*-)(2) generation in human endothelial cells as measured by coelenterazine chemiluminescence. These data support a new mechanism: how ET-1 increases oxidative stress in the vessel wall leading to endothelial dysfunction and enhanced susceptibility to atherosclerosis.
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Obesity is associated with tissue-specific activation of renal angiotensin-converting enzyme in vivo: evidence for a regulatory role of endothelin. Hypertension 2000; 35:329-36. [PMID: 10642320 DOI: 10.1161/01.hyp.35.1.329] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In the C57BL/6J mice model, we investigated whether obesity affects the function or expression of components of the tissue renin-angiotensin system and whether endothelin (ET)-1 contributes to these changes. ACE activity (nmol. L His-Leu. mg protein(-1)) was measured in lung, kidney, and liver in control (receiving standard chow) and obese animals treated for 30 weeks with a high-fat, low cholesterol diet alone or in combination with LU135252, an orally active ET(A) receptor antagonist. ACE mRNA expression was measured in the kidney, and the effects of LU135252 on purified human ACE were determined. Aortic and renal tissue ET-1 protein content was measured, and the vascular contractility to angiotensin II was assessed. Obesity was associated with a tissue-specific increase in ACE activity in the kidney (55+/-4 versus 33+/-3 nmol/L) but not in the lung (34+/-2 versus 32+/-2 nmol/L). Long-term LU135252 treatment completely prevented this activation (13.3+/-0.3 versus 55+/-4 nmol/L, P<0.05) independent of ACE mRNA expression, body weight, or renal ET-1 protein but did not affect pulmonary or hepatic ACE activity. Obesity potentiated contractions in response to angiotensin II in the aorta (from 6+/-2% to 33+/-5% KCl) but not in the carotid artery (4+/-1% to 3.6+/-1% KCl), an effect that was completely prevented with LU135252 treatment (6+/-0.4% versus 33+/-5% KCl). No effect of LU135252 on purified ACE was observed. Thus, obesity is associated with the activation of renal ACE in vivo independent of its mRNA expression and enhanced vascular contractility to angiotensin II. These effects are regulated by ET in an organ-specific manner, providing novel mechanisms by which ET antagonists may exert organ protection.
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Abstract
BACKGROUND Oxidatively modified LDL (oxLDL) plays an important role in the development of atherosclerosis. OxLDL effects, eg, foam cell formation, are mediated in part by the classic scavenger receptor, whereas other effects may involve the recently cloned endothelial oxLDL receptor, LOX-1 (lectinlike oxLDL receptor-1), which is distinct from macrophage scavenger receptors. Because the regulation of LOX-1 must still be defined, we investigated whether LOX-1 is regulated by the potentially proatherosclerotic stimulant angiotensin II (Ang II). METHODS AND RESULTS Using competitive reverse transcription-polymerase chain reaction (RT-PCR), we quantified mRNA expression of LOX-1 in primary cultures of human umbilical vein endothelial cells (HUVECs). After treatment with Ang II for 3 hours (1 nmol/L to 1 micromol/L), LOX-1 mRNA was concentration-dependently induced (from 6.9+/-1.4 to 23.1+/-5.5 relative units [RU] by 1 micromol/L Ang II; P<0.05). The angiotensin II type 1 (AT(1)) receptor antagonist losartan prevented this induction. Incubation of HUVECs with Ang II (100 nmol/L, 3 hours) induced LOX-1 protein expression (212+/-21% of control level; P<0. 01) and uptake of 1,1'-dioctadecyl-3,3,3', 3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled oxLDL (209+/-17% of control level; P<0.05) by an AT(1)-dependent pathway, reaching its maximum after 24 hours (680+/-89%; P<0.05). In internal mammary artery biopsy samples from patients with or without ACE inhibitor treatment before coronary artery bypass surgery, LOX-1 mRNA was downregulated by ACE inhibition (6.4+/-2.0 versus 19.3+/-5. 9 RU; n=12 each; P<0.05). CONCLUSIONS We conclude that LOX-1 is regulated by Ang II in vitro and in vivo, that induction of LOX-1 is mediated by the AT(1) receptor, and that repression of LOX-1 by long-term ACE inhibitor treatment may contribute to the antiatherosclerotic potential of this therapy.
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Abstract
The effect of mechanical strain on transcription and expression of the immediate-early genes, early growth response gene-1 (Egr-1), c-jun, and c-fos, was investigated in neonatal rat aortic vascular smooth muscle (VSM) cells. Cells grown on silicone elastomer plates were subjected to cyclic mechanical strain (1 Hz) at various durations and magnitudes. Egr-1 mRNA increased rapidly in response to cyclic strain, reached a maximum of 10-fold after 30 minutes, and returned to baseline after 4 hours. c-jun exhibited a similar pattern, whereas c-fos mRNA expression was unaffected by strain. Cycloheximide prolonged the increase in Egr-1 and c-jun mRNA and caused superinduction of both. The threshold level of continuous cyclic strain needed to induce expression was 5% for Egr-1 and c-jun. Even a single cycle of mechanical strain that lasted 1 second was sufficient to induce Egr-1 and c-jun mRNA. Strain also increased expression of a transiently transfected Egr-1 promoter-reporter construct. The effect of varying extracellular matrices on strain-induced Egr-1 and c-jun mRNA was examined. In contrast to collagen type 1- and pronectin-coated plates, strain did not significantly alter expression of Egr-1 and c-jun was less induced on laminin-coated plates. On collagen type 1, strain increased Egr-1 protein levels by 2.1-fold at 60 minutes. Immunofluorescence microscopy revealed translocation of Egr-1 to the nucleus in response to strain. These observations indicate that Egr-1 expression and translocation are sensitive to mechanical perturbation of the cell. c-jun is also induced by strain, but c-fos is not. The signal for this induction may involve specific cell-matrix interactions.
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MESH Headings
- Animals
- Animals, Newborn
- Biological Transport
- Cell Nucleus/metabolism
- Cells, Cultured
- Chloramphenicol O-Acetyltransferase
- DNA-Binding Proteins/biosynthesis
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Early Growth Response Protein 1
- Humans
- Immediate-Early Proteins/biosynthesis
- Immediate-Early Proteins/genetics
- Immediate-Early Proteins/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Plasmids/biosynthesis
- Promoter Regions, Genetic/genetics
- Proto-Oncogene Proteins c-jun/biosynthesis
- Proto-Oncogene Proteins c-jun/genetics
- RNA, Messenger/biosynthesis
- Rats
- Stress, Mechanical
- Transcription Factors/biosynthesis
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Up-Regulation
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Mechanism of ET(A)-receptor stimulation-induced increases in intracellular Ca2+ in SK-N-MC cells. Br J Pharmacol 1998; 125:1202-11. [PMID: 9863648 PMCID: PMC1565711 DOI: 10.1038/sj.bjp.0702208] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The mechanism underlying endothelin-1 (ET-1)-induced increases in intracellular Ca2+ concentrations in the human neuroblastoma cell-line SK-N-MC was investigated. ET-receptor agonists increased inositol phosphate (IP)-formation (assessed as accumulation of total [3H]-IPs in [3H]-myo-inositol prelabelled cells) and intracellular Ca2+ (assessed by the FURA-2 method) with an order of potency: ET-1 > sarafotoxin 6b (S6b)> ET-3 = S6c; the ETA-receptor antagonist BQ-123 inhibited both responses with apparent pKi-values of 8.3 and 8.6, respectively, while the ETB-receptor antagonist BQ-788 did not. Pretreatment of the cells with pertussis toxin (PTX, 500 ng ml(-1) overnight) reduced ET-1-induced Ca2+ increases by 46+/-5%, but rather enhanced ET-1-induced IP-formation. Chelation of extracellular Ca2+ by 5 mM EGTA did not affect ET-1-induced IP-formation. However, in the presence of 5 mM EGTA or SKF 96365, an inhibitor of receptor mediated Ca2+ influx (1.0-3.0 x 10(-5) M) ET-1-induced Ca2+ increases were inhibited in normal, but not in PTX-treated cells. [125I]-ET-1 binding studies as well as mRNA expression studies (by RT-PCR) detected only ETA-receptors whereas expression of ETB-receptor mRNA was marginal. ET-1 (10(-8) M) inhibited isoprenaline-evoked cyclic AMP increases; this was antagonized by BQ-123, not affected by BQ-788 and abolished by PTX-treatment. We conclude that SK-N-MC cells contain a homogeneous population of ETA-receptors that couple to IP-formation and inhibition of cyclic AMP formation. Stimulation of these ETA-receptors increases intracellular Ca2+ by at least two mechanisms: a PTX-insensitive IP-mediated Ca2+ mobilization from intracellular stores and a PTX-sensitive influx of extracellular Ca2+.
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Alternative splicing of the primary Fas transcript generating soluble Fas antagonists is suppressed in the failing human ventricular myocardium. Biochem Biophys Res Commun 1997; 239:794-8. [PMID: 9367848 DOI: 10.1006/bbrc.1997.7555] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Apoptosis of cardiomyocytes has been proposed as a factor contributing to severe heart failure. Since the trigger for apoptotic cellular suicide in nonischemic myocardium is unknown, we analyzed in human myocardial tissue the expression of the apoptosis-inducing membrane receptor Fas/APO-1 and of its alternatively spliced soluble isoforms which antagonize Fas by binding of the Fas ligand. Using reverse transcription polymerase chain reaction (RT-PCR) we found mRNA for Fas and 5 isoforms in nonfailing left ventricles, whereas Fas and only one isoform (FasExo6Del) were detectable in failing left ventricles. Standard calibrated, competitive RT-PCR revealed no significant increase of Fas mRNA in failing compared to nonfailing ventricles. However, the mRNA for FasExo6Del, expressed nearly on the same level as Fas in nonfailing ventricles, was decreased about 3-fold in failing ventricles. We propose that this altered expression of the Fas system renders the myocardium more susceptible for Fas-mediated apoptosis in end-stage heart failure.
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