0000000000246801
AUTHOR
Thomas Wallerath
showing 15 related works from this author
Identification of the NO Synthase isoforms Expressed in Human Neutrophil Granulocytes, Megakaryocytes and Platelets
1997
SummaryUsing Western blot and fluorescent immunocytochemistry, NOS III (or ecNOS) and NOS II (or iNOS), but no NOS I (or ncNOS), were identified in preparations of human platelets. Reverse-transcription polymerase chain reactions (RT-PCR) demonstrated NOS III mRNA, but no NOS II mRNA (which is short-lived) and no NOS I mRNA in platelets. Immunofluorescent staining of human bone marrow smears showed the presence of NOS III, but not NOS I in megakaryocytes. A subpopulation of megakaryocytes also expressed NOS II. In preparations of human neutrophils, immunocytochemistry demonstrated NOS I in all cells, whereas no NOS III was detected. The few NOS II positive cells were characterized as contam…
Animal Models of Hypertension
2007
Hypertension affects approximately 25% of adults and is a major risk factor for cardiovascular disease. Although there are currently adequate therapeutic options for humans with hypertension, the molecular mechanisms underlying hypertension are still relatively unknown. The generation of hypertensive animal models provides an excellent modality to not only study the pathophysiology but also test innovative therapeutics. This chapter describes the detailed methods that utilize the drinking water of rats to develop models of nitric oxide synthase (NOS) inhibition-induced, guanosine triphosphate cyclohydrolase (GTPCH) inhibition-induced, and glucocorticoid-induced hypertension.
Activation of protein kinase C alpha and/or epsilon enhances transcription of the human endothelial nitric oxide synthase gene.
1998
In primary human umbilical vein endothelial cells (HUVECs), incubation with phorbol-12-myristate-13-acetate (PMA) enhanced basal and bradykinin-stimulated nitric oxide production. In the HUVEC-derived cell line EA.hy 926, PMA and phorbol-12,13-dibutyrate stimulated endothelial nitric oxide synthase (NOS III) mRNA expression in a concentration- and time-dependent manner. Maximal mRNA expression (3.3-fold increase) was observed after 18 hr. NOS III protein and activity were increased to a similar extent. The specific protein kinase C (PKC) inhibitors bisindolylmaleimide I (1 microM), Gö 6976 [12-(2 cyanoethyl)-6,7,12, 13-tetrahydro-13-methyl-5-oxo-5H-indolo[2,3-a]pyrrolo-[3, 4-c]carbazole] (1…
A blend of polyphenolic compounds explains the stimulatory effect of red wine on human endothelial NO synthase
2005
A high intake of polyphenolic compounds is likely to have beneficial effects on the cardiovascular system. Especially red wine is a rich source of polyphenols, and we have previously shown that French red wine upregulates eNOS, a protective enzyme in the cardiovascular system. The current study tested (poly)phenolic constituents of red wine for their ability to enhance eNOS expression (and the activity of a 3.5-kb human eNOS promoter) in human EA.hy 926 endothelial cells. Of the compounds tested, we found 3,4',5-trihydroxy-trans-stilbene (trans-resveratrol) to be the most efficacious stimulator of eNOS expression (and eNOS transcription), but this compound alone could not explain the total …
Dual effect of ceramide on human endothelial cells: induction of oxidative stress and transcriptional upregulation of endothelial nitric oxide syntha…
2002
Background— Generation of the second-messenger molecule ceramide by stimulated sphingomyelinase activity has been implicated in the inflammatory processes contributing to the pathogenesis of atherosclerosis. However, reports of stimulatory effects of ceramide on endothelial NO production in animal models suggest antiatherosclerotic effects of the molecule. Therefore, we investigated long-term effects of ceramide on NO generation in human endothelial cells. Methods and Results— In human umbilical vein endothelial cells (HUVECs) and in HUVEC-derived EA.hy 926 endothelial cells, C6-ceramide ( N -hexanoyl- d -erythro-sphingosine) reduced the generation of bioactive NO (RFL-6 reporter-cell assa…
Stimulation of endothelial nitric oxide synthase by proinsulin C-peptide.
2003
There is increasing evidence for biological functions of human C-peptide. Recently, we have described that proinsulin C-peptide increases nutritive capillary blood flow and restores erythrocyte deformability in type 1 diabetic patients, whereas it has no such effect in non-diabetic subjects. The aim of the current study was to elucidate cellular mechanisms of this vasodilator effect in vitro by measuring the nitric oxide (NO)-mediated increase of cGMP production in a RFL-6 reporter cell assay and by demonstrating endothelial calcium influx with the Fluo-3 technique. C-peptide increased the release of NO from endothelial NO synthase (eNOS) in bovine aortic endothelial cells in a concentratio…
Resveratrol, a polyphenolic phytoalexin present in red wine, enhances expression and activity of endothelial nitric oxide synthase.
2002
Background— Estrogens can upregulate endothelial nitric oxide synthase (eNOS) in human endothelial cells by increasing eNOS promoter activity and enhancing the binding activity of the transcription factor Sp1. Resveratrol, a polyphenolic phytoalexin found in grapes and wine, has been reported to act as an agonist at the estrogen receptor. Therefore, we tested the effect of this putative phytoestrogen on eNOS expression in human endothelial cells. Methods and Results— Incubation of human umbilical vein endothelial cells (HUVEC) and HUVEC-derived EA.hy 926 cells with resveratrol for 24 to 72 hours upregulated eNOS mRNA expression in a time- and concentration-dependent manner (up to 2.8-fold)…
Red wine increases the expression of human endothelial nitric oxide synthase
2003
Abstract Objectives The study tested the effect of red wine on endothelial-type nitric oxide synthase (eNOS) expression and eNOS activity in human endothelial cells. Background Endothelial-type nitric oxide (NO) synthase exerts vasoprotective effects. Moderate alcohol consumption has been associated with a reduction of cardiovascular disease, and red wine seems to offer more benefits than any other type of drink. However, the molecular basis of this protective effect is unclear. Methods Human endothelial cells were treated with red wine, and eNOS messenger ribonucleic acid (mRNA) expression was measured by RNase protection assay, eNOS protein expression by Western blotting, and eNOS activit…
Regulation of endothelial-type NO synthase expression in pathophysiology and in response to drugs.
2002
In many types of cardiovascular pathophysiology such as hypercholesterolemia and atherosclerosis, diabetes, cigarette smoking, or hypertension (with its sequelae stroke and heart failure) the expression of endothelial NO synthase (eNOS) is altered. Both up- and downregulation of eNOS have been observed, depending on the underlying disease. When eNOS is upregulated, the upregulation is often futile and goes along with a reduction in bioactive NO. This is due to an increased production of superoxide generated by NAD(P)H oxidase and by an uncoupled eNOS. A number of drugs with favorable effects on cardiovascular disease upregulate eNOS expression. The resulting increase in vascular NO producti…
Physiological mechanisms regulating the expression of endothelial-type NO synthase
2002
Although endothelial nitric oxide synthase (eNOS) is a constitutively expressed enzyme, its expression is regulated by a number of biophysical, biochemical, and hormonal stimuli, both under physiological conditions and in pathology. This review summarizes the recent findings in this field. Shear stress, growth factors (such as transforming growth factor-beta, fibroblast growth factor, vascular endothelial growth factor, and platelet-derived growth factor), hormones (such as estrogens, insulin, angiotensin II, and endothelin 1), and other compounds (such as lysophosphatidylcholine) upregulate eNOS expression. On the other hand, the cytokine tumor necrosis factor-alpha and bacterial lipopolys…
Cytokine induction of NO synthase II in human DLD-1 cells: roles of the JAK-STAT, AP-1 and NF-κB-signaling pathways
1998
1. In human epithelial-like DLD-I cells, nitric oxide synthase (NOS) II expression was induced by interferon-gamma (100 u ml(-1)) alone and, to a larger extent, by a cytokine mixture (CM) consisting of interferon-gamma, interleukin-1beta (50 u ml(-1)) and tumor necrosis factor-alpha (10 ng ml(-1)). 2. CM-induced NOS II expression was inhibited by tyrphostin B42 (mRNA down to 1%; nitrite production down to 0.5% at 300 microM) and tyrphostin A25 (mRNA down to 24%, nitrite production down to 1% at 200 microM), suggesting the involvement of janus kinase 2 (JAK-2). Tyrphostin B42 also blocked the CM-induced JAK-2 phosphorylation (kinase assay) and reduced the CM-stimulated STAT1alpha binding act…
Down-regulation of the expression of endothelial NO synthase is likely to contribute to glucocorticoid-mediated hypertension.
1999
Hypertension is a side effect of systemically administered glucocorticoids, but the underlying molecular mechanism remains poorly understood. Ingestion of dexamethasone by rats telemetrically instrumented increased blood pressure progressively over 7 days. Plasma concentrations of Na + and K + and urinary Na + and K + excretion remained constant, excluding a mineralocorticoid-mediated mechanism. Plasma NO 2 − /NO 3 − (the oxidation products of NO) decreased to 40%, and the expression of endothelial NO synthase (NOS III) was found down-regulated in the aorta and several other tissues of glucocorticoid-treated rats. The vasodilator response of resistance arterioles was tested by intravital m…
Dexamethasone lacks effect on blood pressure in mice with a disrupted endothelial NO synthase gene.
2003
Cushing's syndrome and systemic administration of glucocorticoids are associated with hypertension, but the underlying molecular mechanism is only partially understood. We have shown previously that dexamethasone downregulates the expression of the endothelial NO synthase (eNOS) gene in human endothelial cells and in the rat and that this may contribute to the blood pressure-raising effect of the steroid [Proc. Natl. Acad. Sci. USA 96 (1999) 13357]. In the current communication, we demonstrated that dexamethasone increased mean arterial blood pressure in wild-type C-57 Bl6 mice (eNOS+/+ mice), but had no effect on blood pressure in mice with a disrupted eNOS gene (eNOS-/- mice) derived from…
Estrogens increase transcription of the human endothelial NO synthase gene: analysis of the transcription factors involved.
1998
Abstract —Estrogens have been found to reduce the incidence of cardiovascular disease that has been ascribed in part to an increased expression and/or activity of the vasoprotective endothelial NO synthase (NOS III). Some reports have shown that the level of expression of this constitutive enzyme can be upregulated by estrogens. The current study investigates the molecular mechanism of the NOS III upregulation in human endothelial EA.hy 926 cells. Incubation of EA.hy 926 cells with 17β-estradiol or the more stable 17α-ethinyl estradiol enhanced NOS III mRNA and protein expression up to 1.8-fold, without changing the stability of the NOS III mRNA. There was no enhancement of NOS III mRNA af…
Dexamethasone suppresses eNOS and CAT-1 and induces oxidative stress in mouse resistance arterioles
2004
Long-term treatment with glucocorticoids is associated with mild to moderate hypertension. We reported previously that downregulation of endothelial NO synthase (eNOS) expression and activity is likely to contribute to this increase in blood pressure. In the present study, we tested the effects of dexamethasone on the vasodilation of microvascular arterioles using implanted dorsal skin-fold chambers in anesthetized C57BL/6J mice. Experiments were performed on control mice or on mice treated with dexamethasone (0.1–3 mg/kg of body wt). Endothelium-dependent vasodilation in response to ACh (0.1–10 μM) was reduced by dexamethasone in a dose-dependent fashion. Comparable inhibition was seen in …