scholarly journals Histidine-rich glycoprotein does not interfere with interactions between antithrombin III and heparin-like compounds on vascular endothelial cells

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 191-193 ◽  
Author(s):  
K Shimada ◽  
A Kawamoto ◽  
K Matsubayashi ◽  
T Ozawa

Abstract The role of histidine-rich glycoprotein in controlling heparin-like compounds on the endothelial cell surface is still unclear. The effects of this heparin-neutralizing protein on the interaction between antithrombin III and cultured porcine aortic endothelial cells were examined. Displacement of 125I-labeled antithrombin III specifically bound to endothelial cells by unlabeled histidine-rich glycoprotein was much less potent than that by unlabeled antithrombin III. One hundred- fold molar excess of histidine-rich glycoprotein displaced specific 125I-antithrombin III binding only by 20%. Furthermore, the endothelial cell-mediated acceleration of thrombin inactivation by antithrombin III was diminished by protamine sulfate, but was not affected by histidine- rich glycoprotein even at a histidine-rich glycoprotein/antithrombin III molar ratio of approximately 7:1. These data indicate that histidine-rich glycoprotein does not interfere with the interaction of endothelial cell heparin-like compounds with antithrombin III. Thus, it may not play an important role in the modulation of anticoagulant activity of endothelial cells in vivo, suggesting that the commonly accepted view of the probable function of this protein is erroneous.

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 191-193
Author(s):  
K Shimada ◽  
A Kawamoto ◽  
K Matsubayashi ◽  
T Ozawa

The role of histidine-rich glycoprotein in controlling heparin-like compounds on the endothelial cell surface is still unclear. The effects of this heparin-neutralizing protein on the interaction between antithrombin III and cultured porcine aortic endothelial cells were examined. Displacement of 125I-labeled antithrombin III specifically bound to endothelial cells by unlabeled histidine-rich glycoprotein was much less potent than that by unlabeled antithrombin III. One hundred- fold molar excess of histidine-rich glycoprotein displaced specific 125I-antithrombin III binding only by 20%. Furthermore, the endothelial cell-mediated acceleration of thrombin inactivation by antithrombin III was diminished by protamine sulfate, but was not affected by histidine- rich glycoprotein even at a histidine-rich glycoprotein/antithrombin III molar ratio of approximately 7:1. These data indicate that histidine-rich glycoprotein does not interfere with the interaction of endothelial cell heparin-like compounds with antithrombin III. Thus, it may not play an important role in the modulation of anticoagulant activity of endothelial cells in vivo, suggesting that the commonly accepted view of the probable function of this protein is erroneous.


Blood ◽  
2010 ◽  
Vol 115 (20) ◽  
pp. 4130-4137 ◽  
Author(s):  
Jinmin Gao ◽  
Lei Sun ◽  
Lihong Huo ◽  
Min Liu ◽  
Dengwen Li ◽  
...  

Cylindromatosis (CYLD) is a deubiquitinase that was initially identified as a tumor suppressor and has recently been implicated in diverse normal physiologic processes. In this study, we have investigated the involvement of CYLD in angiogenesis, the formation of new blood vessels from preexisting ones. We find that knockdown of CYLD expression significantly impairs angiogenesis in vitro in both matrigel-based tube formation assay and collagen-based 3-dimensional capillary sprouting assay. Disruption of CYLD also remarkably inhibits angiogenic response in vivo, as evidenced by diminished blood vessel growth into the angioreactors implanted in mice. Mechanistic studies show that CYLD regulates angiogenesis by mediating the spreading and migration of vascular endothelial cells. Silencing of CYLD dramatically decreases microtubule dynamics in endothelial cells and inhibits endothelial cell migration by blocking the polarization process. Furthermore, we identify Rac1 activation as an important factor contributing to the action of CYLD in regulating endothelial cell migration and angiogenesis. Our findings thus uncover a previously unrecognized role for CYLD in the angiogenic process and provide a novel mechanism for Rac1 activation during endothelial cell migration and angiogenesis.


Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 1089-1098 ◽  
Author(s):  
T.M. Schlaeger ◽  
Y. Qin ◽  
Y. Fujiwara ◽  
J. Magram ◽  
T.N. Sato

Vascular endothelial cells play essential roles in the function and development of the cardiovascular system. However, due to the lack of lineage-specific markers suitable for molecular and biochemical analyses, very little is known about the molecular mechanisms that regulate endothelial cell differentiation. We report the first vascular endothelial cell lineage-specific (including angioblastic precursor cells) 1.2 kb promoter in transgenic mice. Moreover, deletion analysis of this promoter region in transgenic embryos revealed multiple elements that are required for the maximum endothelial cell lineage-specific expression. This is a powerful molecular tool that will enable us to identify factors and cellular signals essential for the establishment of vascular endothelial cell lineage. It will also allow us to deliver genes specifically into this cell type in vivo to test specifically molecules that have been implicated in cardiovascular development. Furthermore, we have established embryonic stem (ES) cells from the blastocysts of the transgenic mouse that carry the 1.2 kb promoter-LacZ reporter transgene. These ES cells were able to differentiate in vitro to form cystic embryoid bodies (CEB) that contain endothelial cells determined by PECAM immunohistochemistry. However, these in vitro differentiated endothelial cells did not express the LacZ reporter gene. This indicates the lack of factors and/or cellular interactions which are required to induce the expression of the reporter gene mediated by this 1.2 kb promoter in this in vitro differentiation system. Thus this system will allow us to screen for the putative inducers that exist in vivo but not in vitro. These putative inducers are presumably important for in vivo differentiation of vascular endothelial cells.


2011 ◽  
Vol 22 (22) ◽  
pp. 4324-4334 ◽  
Author(s):  
Joshua T. Morgan ◽  
Emily R. Pfeiffer ◽  
Twanda L. Thirkill ◽  
Priyadarsini Kumar ◽  
Gordon Peng ◽  
...  

Changes in blood flow regulate gene expression and protein synthesis in vascular endothelial cells, and this regulation is involved in the development of atherosclerosis. How mechanical stimuli are transmitted from the endothelial luminal surface to the nucleus is incompletely understood. The linker of nucleus and cytoskeleton (LINC) complexes have been proposed as part of a continuous physical link between the plasma membrane and subnuclear structures. LINC proteins nesprin-1, -2, and -4 have been shown to mediate nuclear positioning via microtubule motors and actin. Although nesprin-3 connects intermediate filaments to the nucleus, no functional consequences of nesprin-3 mutations on cellular processes have been described. Here we show that nesprin-3 is robustly expressed in human aortic endothelial cells (HAECs) and localizes to the nuclear envelope. Nesprin-3 regulates HAEC morpho­logy, with nesprin-3 knockdown inducing prominent cellular elongation. Nesprin-3 also organizes perinuclear cytoskeletal organization and is required to attach the centrosome to the nuclear envelope. Finally, nesprin-3 is required for flow-induced polarization of the centrosome and flow-induced migration in HAECs. These results represent the most complete description to date of nesprin-3 function and suggest that nesprin-3 regulates vascular endothelial cell shape, perinuclear cytoskeletal architecture, and important aspects of flow-mediated mechanotransduction.


2015 ◽  
Vol 35 (7) ◽  
pp. 1299-1313 ◽  
Author(s):  
Shan Wang ◽  
Katherine R. Amato ◽  
Wenqiang Song ◽  
Victoria Youngblood ◽  
Keunwook Lee ◽  
...  

Mammaliantargetofrapamycin (mTOR) is a serine/threonine kinase that regulates a diverse array of cellular processes, including cell growth, survival, metabolism, and cytoskeleton dynamics. mTOR functions in two distinct complexes, mTORC1 and mTORC2, whose activities and substrate specificities are regulated by complex specific cofactors, including Raptor and Rictor, respectively. Little is known regarding the relative contribution of mTORC1 versus mTORC2 in vascular endothelial cells. Using mouse models of Raptor or Rictor gene targeting, we discovered that Rictor ablation inhibited vascular endothelial growth factor (VEGF)-induced endothelial cell proliferation and assemblyin vitroand angiogenesisin vivo, whereas the loss of Raptor had only a modest effect on endothelial cells (ECs). Mechanistically, the loss of Rictor reduced the phosphorylation of AKT, protein kinase Cα (PKCα), and NDRG1 without affecting the mTORC1 pathway. In contrast, the loss of Raptor increased the phosphorylation of AKT despite inhibiting the phosphorylation of S6K1, a direct target of mTORC1. Reconstitution of Rictor-null cells with myristoylated AKT (Myr-AKT) rescued vascular assembly in Rictor-deficient endothelial cells, whereas PKCα rescued proliferation defects. Furthermore, tumor neovascularizationin vivowas significantly decreased upon EC-specific Rictor deletion in mice. These data indicate that mTORC2 is a critical signaling node required for VEGF-mediated angiogenesis through the regulation of AKT and PKCα in vascular endothelial cells.


1988 ◽  
Vol 60 (02) ◽  
pp. 226-229 ◽  
Author(s):  
Jerome M Teitel ◽  
Hong-Yu Ni ◽  
John J Freedman ◽  
M Bernadette Garvey

SummarySome classical hemophiliacs have a paradoxical hemostatic response to prothrombin complex concentrate (PCC). We hypothesized that vascular endothelial cells (EC) may contribute to this “factor VIII bypassing activity”. When PCC were incubated with suspensions or monolayer cultures of EC, they acquired the ability to partially bypass the defect of factor VIII deficient plasma. This factor VIII bypassing activity distributed with EC and not with the supernatant PCC, and was not a general property of intravascular cells. The effect of PCC was even more dramatic on fixed EC monolayers, which became procoagulant after incubation with PCC. The time courses of association and dissociation of the PCC-derived factor VIII bypassing activity of fixed and viable EC monolayers were both rapid. We conclude that EC may provide a privileged site for sequestration of constituents of PCC which express coagulant activity and which bypass the abnormality of factor VIII deficient plasma.


1995 ◽  
Vol 74 (04) ◽  
pp. 1045-1049 ◽  
Author(s):  
P Butthep ◽  
A Bunyaratvej ◽  
Y Funahara ◽  
H Kitaguchi ◽  
S Fucharoen ◽  
...  

SummaryAn increased level of plasma thrombomodulin (TM) in α- and β- thalassaemia was demonstrated using an enzyme-linked immunosorbent assay (ELISA). Nonsplenectomized patients with β-thalassaemia/ haemoglobin E (BE) had higher levels of TM than splenectomized cases (BE-S). Patients with leg ulcers (BE-LU) were found to have the highest increase in TM level. Appearance of larger platelets in all types of thalassaemic blood was observed indicating an increase in the number of younger platelets. These data indicate that injury of vascular endothelial cells is present in thalassaemic patients.


1993 ◽  
Vol 265 (4) ◽  
pp. H1424-H1433 ◽  
Author(s):  
R. C. Ziegelstein ◽  
L. Cheng ◽  
P. S. Blank ◽  
H. A. Spurgeon ◽  
E. G. Lakatta ◽  
...  

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.


1996 ◽  
Vol 316 (3) ◽  
pp. 703-707 ◽  
Author(s):  
Ralf BIRKENHÄGER ◽  
Bernard SCHNEPPE ◽  
Wolfgang RÖCKL ◽  
Jörg WILTING ◽  
Herbert A. WEICH ◽  
...  

Vascular endothilial growth factor (VEGF) and placenta growth factor (PIGF) are members of a dimeric-growth-factor family with angiogenic properties. VEGF is a highly potent and specific mitogen for endothelial cells, playing a vital role in angiogenesis in vivo. The role of PIGF is less clear. We expressed the monomeric splice forms VEGF-165, VEGF-121, PIGF-1 and PlGF-2 as unfused genes in Escherichia coli using the pCYTEXP expression system. In vitro dimerization experiments revealed that both homo- and hetero-dimers can be formed from these monomeric proteins. The dimers were tested for their ability to promote capillary growth in vivo and stimulate DNA synthesis in cultured human vascular endothelial cells. Heterodimers comprising different VEGF splice forms, or combinations of VEGF/PlGF splice forms, showed mitogenic activity. The results demonstrate that four different heterodimeric growth factors are likely to have as yet uncharacterized functions in vivo.


Sign in / Sign up

Export Citation Format

Share Document