scholarly journals Stereoselectivity of ectonucleotidases on vascular endothelial cells

1983 ◽  
Vol 214 (3) ◽  
pp. 975-981 ◽  
Author(s):  
N J Cusack ◽  
J D Pearson ◽  
J L Gordon
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Thiol Group ◽  
Side Chain ◽  
Vascular Endothelial ◽  
Nucleotide Analogues ◽  
Aortic Endothelial Cells ◽  
Nucleotide Analogue ◽  
High Degree ◽  
Aortic Endothelial

We have investigated the stereoselectivity of ectonucleotidases (nucleoside triphosphatase, EC 3.6.1.15; nucleoside diphosphatase, EC 3.6.1.6; 5′-nucleotidase, EC 3.1.3.5) on pig aortic endothelial cells using two classes of nucleotide analogue. In experiments with nucleotide enantiomers in which the natural D-ribofuranosyl moiety is replaced by an L-ribofuranosyl moiety, the rate of catabolism of 100 microM-L-ATP was one-fifth that of D-ATP, the rate of catabolism of 100 microM-L-ADP was one-fifteenth that of D-ADP and there was no detectable catabolism of 100 microM-L-AMP. Each of the L-enantiomers inhibited, apparently competitively, the catabolism of the corresponding D-enantiomer; Ki values were approx. 0.6 mM, 1.0 mM and 3.9 mM for L-ATP, L-ADP and L-AMP respectively. Experiments with adenosine 5′-[beta, gamma-imido]triphosphate and with D- and L-enantiomers of adenosine 5′-[beta, gamma-methylene]triphosphate revealed modest ectopyrophosphatase activity, undetectable in experiments with natural nucleotides, which was also stereoselective. Use of phosphorothioate nucleotide analogues demonstrated that ATP catabolism was virtually stereospecific with respect to the geometry of the thiol group substituted on the beta-phosphate: the Rp isomer was degraded, whereas there was little or no breakdown of the Sp isomer. ADP catabolism was also stereospecific with respect to the geometry of the thiol group substituted on the alpha-phosphate: the Sp isomer but not the Rp isomer was degraded. The geometry of thiol-group substitution on the alpha-phosphate had no effect on ATP catabolism to ADP. There was no detectable catabolism of analogues with thiol-group substitution on the terminal phosphate. Each of the phosphorothioate analogues that was catabolized broke down at a rate similar to that of the natural nucleotide from which it was derived. These results demonstrate that the ectonucleotidases on pig aortic endothelial cells exhibit a high degree of stereoselectivity, characteristic for each enzyme, both with respect to the ribofuranosyl moiety and to the phosphate side chain.

Modulation of calcium homeostasis in cultured rat aortic endothelial cells by intracellular acidification

1993 ◽  
Vol 265 (4) ◽  
pp. H1424-H1433 ◽  
Author(s):  
R. C. Ziegelstein ◽  
L. Cheng ◽  
P. S. Blank ◽  
H. A. Spurgeon ◽  
E. G. Lakatta ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Cytosolic Calcium ◽  
Ph Sensitive ◽  
Vascular Endothelial ◽  
Intracellular Acidification ◽  
Cytosolic Ph ◽  
Aortic Endothelial Cells ◽  
Endothelial Monolayers ◽  
Aortic Endothelial

Acidosis produces vasodilation in a process that may involve the vascular endothelium. Because synthesis and release of endothelium-derived vasodilatory substances are linked to an increase in cytosolic calcium concentration ([Ca2+]i), we examined the effect of intracellular acidification on cultured rat aortic endothelial cells loaded either with the pH-sensitive probe carboxy-seminaphthorhodafluor-1 or the Ca(2+)-sensitive fluorescent probe indo 1. The basal cytosolic pH (pHi) of endothelial monolayers in a 5% CO2-HCO3- buffer was 7.27 +/- 0.02 and that in a bicarbonate-free solution was 7.22 +/- 0.03. Acidification was induced either by removal of NH4Cl (delta pHi = -0.10 +/- 0.02), changing from a bicarbonate-free to a 5% CO2-HCO3(-)-buffered solution at constant buffer pH (delta pHi = -0.18 +/- 0.03), or changing from a 5% to a 20% CO2-HCO3- solution (delta pHi = -0.27 +/- 0.07). Regardless of the method used, intracellular acidification increased [Ca2+]i as indexed by indo 1 fluorescence. The increase in [Ca2+]i induced by changing from a 5 to a 20% CO2-HCO3- solution was not significantly altered by removal of buffer Ca2+ either before or after depletion of bradykinin- and thapsigargin-sensitive intracellular Ca2+ stores. Thus intracellular acidification of vascular endothelial cells releases Ca2+ into the cytosol either from pH-sensitive intracellular buffer sites, mitochondria, or from bradykinin- and thapsigargin-insensitive intracellular stores. This Ca2+ mobilization may be linked to endothelial synthesis and release of vasodilatory substances during acidosis.

Intracellular pathways of insulin transport across vascular endothelial cells

1988 ◽  
Vol 255 (4) ◽  
pp. C459-C464 ◽  
Author(s):  
H. L. Hachiya ◽  
P. A. Halban ◽  
G. L. King
Keyword(s):  
Endothelial Cells ◽  
Insulin Receptor ◽  
Vascular Endothelial Cells ◽  
Insulin Degradation ◽  
Vascular Endothelial ◽  
Aortic Endothelial Cells ◽  
Lysosomal Protease ◽  
Insulin Transport ◽  
Bovine Aortic Endothelial Cells ◽  
Aortic Endothelial

Processing and transport of hormones across vascular endothelial cells may modulate hormone action at subendothelial tissue sites. Insulin was transported across cultured rat capillary and bovine aortic endothelial cells, after a delay of 5-10 min, at a constant rate for 60 min at 37 degrees C. 125I-labeled insulin transport was inhibited by 88 +/- 11% (SE, n = 4) and 75 +/- 18% (SE, n = 4) in the presence of anti-insulin receptor antibody and unlabeled insulin (at 10(-7) M), respectively. Reverse phase high-performance liquid chromatography showed 88% of the 125I-insulin transported over 60 min was indistinguishable from the 125I-insulin added to the cells at 4 degrees C. In aortic endothelial cells preincubated with 2.3 x 10(-9) M of insulin for 24 h, insulin receptor binding was downregulated by 67%, and 125I-insulin transport was decreased by 52 +/- 11%. The proton ionophore monensin (0.05 mM) increased the internalized insulin in bovine aortic endothelial cells by 78%, with a corresponding decrease in 125I-insulin released by 76 +/- 2% (SE, n = 4). 125I-insulin transport across the aortic endothelial cell monolayer was similarly decreased (54 +/- 12%, SE, n = 4) by monensin. In contrast, the lysosomal protease inhibitor leupeptin had no effect. Degradation and transport were similarly dissociated by low temperature. At 15 degrees C, no significant insulin degradation was detected, whereas 125I-insulin release from the cells continued at 30 +/- 3% of the rate at 37 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Swelling-activated K fluxes in vascular endothelial cells: volume regulation via K-Cl cotransport and K channels

1993 ◽  
Vol 265 (3) ◽  
pp. C763-C769 ◽  
Author(s):  
P. B. Perry ◽  
W. C. O'Neill
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Regulatory Volume Decrease ◽  
Cell Swelling ◽  
Ionophore A23187 ◽  
Vascular Endothelial ◽  
Aortic Endothelial Cells ◽  
K Channels ◽  
Volume Decrease ◽  
Aortic Endothelial

K efflux pathways responsible for regulatory volume decrease (RVD) were examined in bovine aortic endothelial cells. Hypotonic swelling produced a rapid and reversible threefold increase in bumetanide-insensitive 86Rb efflux. Swelling-activated 86Rb efflux was inhibited 43% when Cl was replaced with NO3, and this Cl-dependent efflux was inhibited by 1 mM furosemide. Neither Cl replacement nor furosemide inhibited the efflux stimulated by a Ca ionophore (A23187) in isotonic medium. Swelling-activated 86Rb efflux was also inhibited by 4,4'-diisothiocyanostilbene-2,2'-disulfonate but not by dinitrostilbenedisulfonate. Cell swelling induced a volume-regulatory K loss that was incomplete in hypotonic medium but complete and more rapid when bumetanide was added or when cells were swollen isosmotically. K loss in the presence of bumetanide was partially blocked by furosemide. We conclude that two separate swelling-activated K fluxes mediate RVD in aortic endothelial cells: a Cl-dependent, furosemide-sensitive, but bumetanide-insensitive flux that is consistent with K-Cl cotransport, and a Cl-independent efflux that presumably is mediated by K channels.

scholarly journals Metabolism of inositol phosphates in ATP-stimulated vascular endothelial cells

1991 ◽  
Vol 277 (1) ◽  
pp. 103-110 ◽  
Author(s):  
S Pirotton ◽  
B Verjans ◽  
J M Boeynaems ◽  
C Erneux
Keyword(s):  
Endothelial Cells ◽  
Inositol Phosphates ◽  
Vascular Endothelial Cells ◽  
P2y Receptors ◽  
Vascular Endothelial ◽  
Aortic Endothelial Cells ◽  
Control Value ◽  
Time Courses ◽  
Fold Stimulation ◽  
Aortic Endothelial

The accumulation of InsP1, InsP2, InsP3 and InsP4 isomers was investigated in bovine aortic endothelial cells labelled with [3H]inositol and stimulated with ATP. The separation of these isomers was performed by ion-pairing reverse-phase h.p.l.c. on a mu Bondapack C18 column for the InsP3 and InsP4 isomers and by ion-exchange h.p.l.c. on a Partisil SAX column for the InsP1 and InsP2 isomers. In unstimulated endothelial cells, a large amount of material was co-eluted with InsP5 and InsP6, whereas amounts of InsP3 and InsP4 were small. The addition of ATP (100 microM) induced a striking (35-fold stimulation) and transient increase of Ins(1,4,5)P3 that was maximal around 15 s. This peak was followed by a more sustained accumulation of Ins(1,3,4,5)P4 and Ins(1,3,4)P3, but the amounts of these two metabolites accumulated in response to ATP were much smaller than that of Ins(1,4,5)P3. The increase in InsP2 isomers in response to ATP had similar characteristics: a rapid and transient accumulation of Ins(1,4)P2, followed by an increase of Ins(3,4)P2 and Ins(1,3)P2, which was more sustained but had a smaller magnitude. ATP also induced the accumulation of both Ins1P and Ins4P, but with different time courses: the level of Ins4P was maximal at 1 min (60 times the control value) and returned to baseline after 5 min, whereas the increase in Ins1P was undetectable at 1 min and reached a maximum after 5 min, which represented 240% of the basal level. These data indicate that Ins(1,4,5)P3, which is rapidly formed in aortic endothelial cells as a result of activation of P2Y receptors, is preferentially metabolized at early times (less than 1 min) by a 5-phosphatase, with the sequential formation of Ins(1,4)P2 and Ins4P. Afterwards, a small but sustained increase in the content of Ins(1,3,4)P3, Ins(1,3)P2, Ins(3,4)P2 and Ins1P was observed, reflecting the activation of the Ins(1,4,5)P3 3-kinase.

scholarly journals Orai–vascular endothelial-cadherin signaling complex regulates high-glucose exposure-induced increased permeability of mouse aortic endothelial cells

2021 ◽  
Vol 9 (1) ◽  
pp. e002085
Author(s):  
Yuan Wei ◽  
Suwen Bai ◽  
YanHeng Yao ◽  
Wenxuan Hou ◽  
Junwei Zhu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Membrane ◽  
High Glucose ◽  
Expression Level ◽  
Vascular Endothelial ◽  
Aortic Endothelial Cells ◽  
Downstream Signaling ◽  
Signaling Complex ◽  
Aortic Endothelium ◽  
Aortic Endothelial

IntroductionDiabetes-associated endothelial barrier function impairment might be linked to disturbances in Ca2+ homeostasis. To study the role and molecular mechanism of Orais–vascular endothelial (VE)-cadherin signaling complex and its downstream signaling pathway in diabetic endothelial injury using mouse aortic endothelial cells (MAECs).Research design and methodsThe activity of store-operated Ca2+ entry (SOCE) was detected by calcium imaging after 7 days of high-glucose (HG) or normal-glucose (NG) exposure, the expression levels of Orais after HG treatment was detected by western blot analysis. The effect of HG exposure on the expression of phosphorylated (p)-VE-cadherin and VE-cadherin on cell membrane was observed by immunofluorescence assay. HG-induced transendothelial electrical resistance was examined in vitro after MAECs were cultured in HG medium. FD-20 permeability was tested in monolayer aortic endothelial cells through transwell permeability assay. The interactions between Orais and VE-cadherin were detected by co-immunoprecipitation and immunofluorescence technologies. Immunohistochemical experiment was used to detect the expression changes of Orais, VE-cadherin and p-VE-cadherin in aortic endothelium of mice with diabetes.Results(1) The expression levels of Orais and activity of SOCE were significantly increased in MAECs cultured in HG for 7 days. (2) In MAECs cultured in HG for 7 days, the ratio of p-VE-cadherin to VE-cadherin expressed on the cell membrane and the FD-20 permeability in monolayer endothelial cells increased, indicating that intercellular permeability increased. (3) Orais and VE-cadherin can interact and enhance the interaction ratio through HG stimulation. (4) In MAECs cultured with HG, the SOCE activator ATP enhanced the expression level of p-VE-cadherin, and the SOCE inhibitor BTP2 decreased the expression level of p-VE-cadherin. (5) Significantly increased expression of p-VE-cadherin and Orais in the aortic endothelium of mice with diabetes.ConclusionHG exposure stimulated increased expression of Orais in endothelial cells, and increased VE-cadherin phosphorylation through Orais–VE-cadherin complex and a series of downstream signaling pathways, resulting in disruption of endothelial cell junctions and initiation of atherosclerosis.

scholarly journals Bovine brain and pituitary fibroblast growth factors: comparison of their abilities to support the proliferation of human and bovine vascular endothelial cells.

1983 ◽  
Vol 97 (6) ◽  
pp. 1677-1685 ◽  
Author(s):  
D Gospodarowicz ◽  
J Cheng ◽  
M Lirette
Keyword(s):  
Endothelial Cells ◽  
Growth Factors ◽  
Cell Cultures ◽  
Vascular Endothelial Cells ◽  
Fibroblast Growth Factors ◽  
Low Density ◽  
Vascular Endothelial ◽  
Fibroblast Growth ◽  
Aortic Endothelial Cells ◽  
Bovine Aortic Endothelial Cells

The mitogenic effects of brain and pituitary fibroblast growth factors (FGF) on vascular endothelial cells derived from either human umbilical vein or bovine aortic arch have been compared. Both brain and pituitary FGF are mitogenic for low density human umbilical endothelial (HUE) cell cultures maintained on either fibronectin- or laminin-coated dishes or on biomatrices produced by cultured cells such as bovine corneal endothelial cells or the teratocarcinoma cell line PF-HR-9. Pituitary FGF triggered the proliferation of HUE cells at concentrations as low as 0.25 ng/ml, with a half-maximal response at 0.55 ng/ml and optimal effect at 2.5 to 5 ng/ml. It was 50,000-fold more potent than commercial preparations of endothelial cell growth factor and 40 times more potent than commercial preparations of pituitary FGF. Similar results were observed when the effect of pituitary FGF was tested on low density cultures of adult bovine aortic endothelial cells. When the activity of brain and pituitary FGF on low density HUE cell cultures was compared, both mitogens were active. To confirm the presence in brain extract of both acidic and neutral, as well as of basic mitogen, for HUE cells, brain tissues were extracted at acidic (4.5), neutral (7.2), and basic (8.5) pH. The three types of extracts were equally potent in supporting the proliferation of either HUE or adult bovine aortic endothelial cells. When the various extracts were absorbed at pH 6.0 on a carboxymethyl Sephadex C-50 column, the neutral and basic extracts had an activity after adsorption similar to that of unadsorbed extracts. In contrast, extracts prepared at pH 4.5 lost 90-95% of their activity which was recovered in the adsorbed fraction containing FGF.

scholarly journals Thioredoxin reductase regulates the induction of haem oxygenase-1 expression in aortic endothelial cells

2006 ◽  
Vol 394 (1) ◽  
pp. 207-216 ◽  
Author(s):  
Wendy L. Trigona ◽  
Isis K. Mullarky ◽  
Yuzhang Cao ◽  
Lorraine M. Sordillo
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Oxidant Stress ◽  
Thioredoxin Reductase ◽  
Aortic Endothelial Cells ◽  
Glutathione Peroxidase 1 ◽  
Thioredoxin Reductase 1 ◽  
Haem Oxygenase ◽  
Se Deficiency ◽  
Aortic Endothelial

Certain selenoproteins such as GPX-1 (glutathione peroxidase-1) and TrxR1 (thioredoxin reductase-1) possess important antioxidant defence functions in vascular endothelial cells. Reduced selenoprotein activity during dietary selenium (Se) deficiency can result in a compensatory increase of other non-Se-dependent antioxidants, such as HO-1 (haem oxygenase-1) that may help to counteract the damaging effects of oxidant stress. However, the role of individual selenoproteins in regulating vascular-derived protective gene responses such as HO-1 is less understood. Using an oxidant stress model based on Se deficiency in BAECs (bovine aortic endothelial cells), we sought to determine whether TrxR1 activity may contribute to the differential regulation of HO-1 expression as a function of altered redox environment. Se-sufficient BAECs up-regulated HO-1 expression following stimulation with the pro-oxidant, 15-HPETE (15-hydroperoxyeicosatetraenoic acid), and levels of this antioxidant inversely correlated with EC apoptosis. While Se-deficient BAECs exhibited higher basal levels of HO-1, it was not up-regulated upon 15-HPETE treatment, which resulted in significantly higher levels of pro-apoptotic markers. Subsequent results showed that HO-1 induction depended on the activity of TrxR1, as proved with chemical inhibitor studies and direct inhibition with TrxR1 siRNA. Finally, restoring intracellular levels of the reduced substrate Trx (thioredoxin) in Sedeficient BAECs was sufficient to increase HO-1 activation following 15-HPETE stimulation. These data provide evidence for the involvement of the Trx/TrxR system, in the regulation of HO-1 expression in BAECs during pro-oxidant challenge.

Presence of hemoglobin inside aortic endothelial cells after cell-free hemoglobin administration in guinea pigs

1999 ◽  
Vol 276 (2) ◽  
pp. H766-H770 ◽  
Author(s):  
Béatrice Faivre-Fiorina ◽  
Alexis Caron ◽  
Céline Fassot ◽  
Isabelle Fries ◽  
Patrick Menu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Immunohistochemical Staining ◽  
Vascular Endothelial Cells ◽  
Oxygen Carrier ◽  
Molecular Size ◽  
Oxygen Carriers ◽  
Aortic Endothelial Cells ◽  
Subunit Dissociation ◽  
Vasoactive Factors ◽  
Aortic Endothelial

The endothelium is the production site of several potent vasoactive factors that contribute to the modulation of the vascular tone. Because hemoglobin-based oxygen carriers (HBOC) have been demonstrated to cause vasoconstriction and thereby increase arterial pressure by interacting with endothelium-derived factors such as nitric oxide and endothelin-1, we hypothesized that hemoglobin could penetrate into the endothelial cells. Therefore, we investigated the presence of hemoglobin into guinea pig aortic endothelial cells by immunohistochemical staining after exchange transfusion with a hemoglobin-based oxygen carrier. Despite the large molecular size of HBOC due to chemical modifications designed to prevent hemoglobin subunit dissociation and extravascular leakage, hemoglobin was detectable by immunohistochemical staining into the endothelial cells. These findings suggest that the vascular endothelial cells could uptake hemoglobin by endocytosis mechanisms or could help hemoglobin to cross the endothelial barrier toward media by transcytosis mechanisms. These findings are very important to lead future investigations to the mechanisms by which HBOC cause vasoconstriction.

Sign in / Sign up

Export Citation Format

Share Document