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.

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)

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.

scholarly journals Confluence of Vascular Endothelial Cells Induces Cell Cycle Exit by Inhibiting p42/p44 Mitogen-Activated Protein Kinase Activity

1999 ◽  
Vol 19 (4) ◽  
pp. 2763-2772 ◽  
Author(s):  
Francesc Viñals ◽  
Jacques Pouysségur
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Growth Factors ◽  
Vascular Endothelial Cells ◽  
Mitogen Activated Protein Kinase ◽  
Vascular Endothelial ◽  
Cell Cycle Exit ◽  
Mapk Activation ◽  
Mapk Activity ◽  
Mitogen Activated Protein

ABSTRACT Like other cellular models, endothelial cells in cultures stop growing when they reach confluence, even in the presence of growth factors. In this work, we have studied the effect of cellular contact on the activation of p42/p44 mitogen-activated protein kinase (MAPK) by growth factors in mouse vascular endothelial cells. p42/p44 MAPK activation by fetal calf serum or fibroblast growth factor was restrained in confluent cells in comparison with the activity found in sparse cells. Consequently, the induction of c-fos, MAPK phosphatases 1 and 2 (MKP1/2), and cyclin D1 was also restrained in confluent cells. In contrast, the activation of Ras and MEK-1, two upstream activators of the p42/p44 MAPK cascade, was not impaired when cells attained confluence. Sodium orthovanadate, but not okadaic acid, restored p42/p44 MAPK activity in confluent cells. Moreover, lysates from confluent 1G11 cells more effectively inactivated a dually phosphorylated active p42 MAPK than lysates from sparse cells. These results, together with the fact that vanadate-sensitive phosphatase activity was higher in confluent cells, suggest that phosphatases play a role in the down-regulation of p42/p44 MAPK activity. Enforced long-term activation of p42/p44 MAPK by expression of the chimera ΔRaf-1:ER, which activates the p42/p44 MAPK cascade at the level of Raf, enhanced the expression of MKP1/2 and cyclin D1 and, more importantly, restored the reentry of confluent cells into the cell cycle. Therefore, inhibition of p42/p44 MAPK activation by cell-cell contact is a critical step initiating cell cycle exit in vascular endothelial cells.

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.

Abstract 476: Attenuated Activities of Mitochondria in Vascular Endothelial Cells Exposed to Oxidized or Glycated Low Density Lipoprotein

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Garry X Shen ◽  
Subir K Roy Chowdhury
Keyword(s):  
Endothelial Cells ◽  
Respiratory Chain ◽  
Complex I ◽  
Vascular Endothelial Cells ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Mitochondrial Respiratory Chain ◽  
Low Density ◽  
Vascular Endothelial ◽  
Glycated Ldl

Hyperglycemia and dyslipoproteinemia are two major biochemical markers of diabetes. Elevated low density lipoprotein (LDL) is a classical risk factor for atherosclerotic cardiovascular disease. Our previous studies demonstrated that oxidized LDL (ox-LDL) and glycated LDL (gly-LDL) increased the generation of reactive oxygen species (ROS) in vascular endothelial cells. ROS is implicated in endothelial dysfunction and diabetic vascular complications. Mitochondria are an important source of ROS in the body. We hypothesize that ox-LDL or gly-LDL might affect the activity of mitochondrial respiratory chain. We evaluated the activities of mitochondrial respiratory chain complexes in porcine aortic endothelial cells (PAEC) using OROBORS oxygraph. The oxygraph was used as a highly sensitive tool to evaluate mitochondrial complex activity in freshly harvested and digitonin-permeabilized PAEC (for Complex I, the rotenone-sensitive oxidation of glutamate + malate in the presence of ADP; Complex II, antimycin A-sensitive oxidation of succinate; Complex IV, potassium cyanide-sensitive oxidation of ascorbate + TMPD). The oxygen consumption in Complex I, II and IV of PAEC was significantly decreased by >12 h of incubation with LDL, ox-LDL or gly-LDL compared to control cultures. Attenuated activity of succinate cytochrome C reductase was detected in EC treated with LDL, ox-LDL or gly-LDL for 24 h. Decreased levels of respiratory control ratio were detected in EC treated with LDL or ox-LDL for 6 h, but not for 2 h, compared to control. Impaired activity of mitochondrial complexes can cause electron leakage in the respiratory chain and substantially increase ROS formation. The findings suggest that oxidized or glycated LDL attenuates mitochondrial activities in vascular EC, which may contribute to increased ROS generation and endothelial dysfunction induced by the atherogenic lipoproteins (supported by operating grants from Canadian Institute of Health Research and Canadian Diabetes Association).

Sign in / Sign up

Export Citation Format

Share Document