Showing papers on "Vascular endothelial growth factor B published in 1990"

Production of vascular endothelial cell growth factor

Abstract: There is described an isolated vascular endothelial cell growth factor selected from the group consisting of bovine vascular endothelial cell growth factor of 120 amino acids and human vascular endothelial cell growth factor of 121 amino acids. The vascular endothelial cell growth factor is useful in the treatment of wounds in which neovascularization or reendothelialization is required for healing.

Oxygen tension regulates the expression of the platelet-derived growth factor-B chain gene in human endothelial cells.

Abstract: Hypoxic states are associated with abnormal proliferation and constriction of the smooth muscle cells surrounding the distal vessels of the lung. In hypoxic as well as in normal states, the endothelial cell layer may play a key role in controlling smooth muscle tone by secreting a number of vasoactive agents. Platelet-derived growth factor (PDGF), produced by endothelial cells, is a major growth factor for vascular smooth muscle cells and a powerful vasoconstrictor. It consists of a disulfide-linked dimer of two related peptides, A and B, that are products of two different genes. We found that hypoxic conditions (0-3% oxygen environments) significantly increased PDGF-B mRNA in cultured human umbilical vein endothelial cells by enhancing the transcriptional rate of this gene. This increase was inversely proportional to oxygen tension and was reversible upon reexposure of cells to a 21% oxygen atmosphere. mRNA levels of PDGF-A were not affected nor was the overall rate of cellular gene transcription increased in response to hypoxia. These studies indicate that endothelial cells are not only capable of sensing oxygen tension, but are also able to discriminate and respond to even small differences in oxygen tension resulting in dramatic upregulation of the PDGF-B chain gene.

Purification of a glycoprotein vascular endothelial cell mitogen from a rat glioma-derived cell line.

Abstract: A growth factor that is mitogenic for vascular endothelial cells, with an ED50 of approximately 1 ng/ml, has been purified 170,000-fold to apparent homogeneity from tissue culture medium conditioned by a rat glioma-derived cell line The pure protein is a 46-kDa dimer composed of two subunits of equivalent mass as established by comparison of migration in SDS/polyacrylamide gels with and without prior reduction This glioma-derived growth factor is a glycoprotein and is not mitogenic for BALB/c 3T3 fibroblasts, properties that further distinguish it from other well-characterized vascular endothelial cell mitogens In contrast to acidic and basic fibroblast growth factors and to platelet-derived endothelial cell growth factor, which have no secretory leader sequences and might only be released by leakage from damaged cells, the glycoprotein nature of this mitogen implies that it is processed through the glycosylating secretory pathway This secretable growth factor could, therefore, be readily available in the extracellular space under normal physiological conditions in vivo to promote vascular endothelial cell proliferation associated with blood-vessel growth and maintenance

Interleukin 1 is an autocrine regulator of human endothelial cell growth.

Abstract: Proliferation of endothelial cells is regulated through the autocrine production of growth factors and the expression of cognate surface receptors. In this study, we demonstrate that interleukin 1 (IL-1) is an inhibitor of endothelial growth in vitro and in vivo. IL-1 arrested growing, cultured endothelial cells in G1 phase; inhibition of proliferation was dose dependent and occurred in parallel with occupancy of endothelial surface IL-1 receptors. In an angiogenesis model, IL-1 could inhibit fibroblast growth factor-induced vessel formation. The autocrine nature of the IL-1 effect on endothelial proliferation was demonstrated by the observation that occupancy of cell-surface receptors by endogenous IL-1 depressed cell growth. The potential significance of this finding was emphasized by the detection of IL-1 in the native endothelium of human umbilical veins. A mechanism by which IL-1 may exert its inhibitory effect on endothelial cell growth was suggested by studies showing that IL-1 decreased the expression of high-affinity fibroblast growth factor binding sites on endothelium. These results point to a potentially important role of IL-1 in regulating blood vessel growth and suggest that autocrine production of inhibitory factors may be a mechanism controlling proliferation of normal cells.

DNA sequences encoding bVEGF120 and hVEGF121 and methods for the production of bovine and human vascular endothelial cell growth factors, bVEGF120 and hVEGF121

Abstract: Isolated DNA sequences, expression vectors and transformant cells are provided which allow for the large scale production of vascular endothelial cell growth factor. The vascular endothelial cell growth factor is useful in the treatment of wounds in which neovascularization or reendothelialization is required for healing.

Stimulus-Secretion Coupling in Vascular Endothelial Cells

Abstract: Endothelium contributes to regulation of vasomotor tone through secretion of two well-characterized vasodilator substances, prostacyclin and endothelium­ derived relaxing factor (EDRF). Endothelial cells may also secrete the en­ dothelium-dependent vasodilators ATP, acetylcholine, and substance P, and at least one peptide vasoconstrictor substance, endothelin. Endothelium­ derived vasoactive agents may be important in mediating the influence of flow on vasomotor tone, vascular geometry, and angiogenesis (35). A second function of endothelium is regulation of intravascular thrombosis. This may be promoted by secretion of platelet adhesion proteins including thrombospondin, fibronectin, collagen, and von Willebrand factor (VWF), but prevented by the secretion of prostacyclin and EDRF, which inhibit platelet activation synergistically. Endothelium promotes coagulation through expression of tissue factor and secretion of factor V, and plasminogen activa­ tor inhibitor (PAl), but inhibits coagUlation through secretion of thrombomod­ ulin and tissue plasminogen activator (TPA). Endothelial secretion of mitogens and growth inhibitors for vascular smooth muscle may be important in atherogenesis. Endothelial regulation of the extravasation of leucocytes by expression of adhesion proteins and secre-

Conditioned Medium from Mouse Sarcoma 180 Cells Contains Vascular Endothelial Growth Factor

Abstract: Medium conditioned by mouse sarcoma 180 cells stimulates the growth of capillary endothelial cells. The growth factor produced by mouse sarcoma 180 cells is heparin-binding, dithiothreitol-sensitive, endothelial cell specific, and secreted into the medium. The characteristics of this mouse sarcoma-derived growth factor are very similar to those of vascular endothelial growth factor (VEGF) first described by Ferrara and Henzel (1989). The N-terminal amino acid sequences of the two growth factors are similar. Since the amino acid sequence of vascular permeability factor (VPF) is essentially identical to that of VEGF, a Western blot of mouse sarcoma 180-derived endothelial growth factor was probed with a polyclonal antibody raised against human VPF. This antibody reacted with several proteins of approximately 23 kDa, suggesting the presence of multiple forms of a VEGF-like protein. A full length cDNA probe for bovine VEGF reacted strongly with RNA isolated from mouse sarcoma 180 cells. We conclude that an endothelial growth factor found in conditioned medium from mouse sarcoma 180 cells is VEGF.

The control of vascular endothelial cell injury.

Abstract: The mechanism by which MCI-186 showed a potent cytoprotective effect on the in vitro endothelial cell injury due to 15-HPETE was studied Stimulation of human leukocytes with various chemical mediators such as TPA, f-Met-Leu-Phe, LTB4, etc elicited the production of active oxygens, which could be detected by luminol-dependent chemiluminescence Among the chemical mediators tested, TPA elicited the chemiluminescence the most, and f-Met-Leu-Phe and LTB4 came next When the leukocytes were directly placed on a monolayer of cultured endothelial cells, followed by stimulating the leukocytes with TPA, severe endothelial cell injury was observed The effect of TPA was dose dependent There was good correlation between the active oxygen releasing activity and the cytotoxic activity When the leukocytes were placed on a filter which was set apart from the monolayer of endothelial cell in a culture dish, and stimulated the leukocytes with TPA, no cytotoxicity was observed These data strongly suggest that the substance responsible for the cytotoxicity must be a very labile and short-lived substance, presumably active oxygens On the other hand, MCI-186 was found to have a complete quenching activity to the chemiluminescence due to active oxygens in the TPA-leukocyte system Taken together, these factors indicate that the potent cytoprotective effect of MCI-186 may be due to its specific radical scavenging activity

Modulation of Endothelial Hemostatic Properties: An Active Role in the Host Response

Abstract: As the cells forming the luminal vascular surface, endothelium regulates both barrier function, and pro- and anticoagulant reactions. Endothelial cells can do this by controlling the expression of cell surface molecules, such as receptors that regulate the hemostatic balance and those that affect permeability across the endothelial monolayer. This regulation occurs in response to environmental stimuli, such as cytokines, which have a central role in inflammation, or glucose-modified proteins, which accumulate in the vasculature in aging and diabetes and are associated with vascular complications. The endothelial cell emerges as a dynamic regulator maintaining homeostasis in the quiescent state and contributing to the pathogenesis of vascular lesions in the stimulated state.

The role of platelet-activating factor in endothelial cells.

Abstract: Endothelial cells activated by receptor-mediated agonists, particularly those involved in inflammation and thrombosis, synthesize platelet-activating factor and express it on their surfaces. This PAF serves as a signal for neutrophils, and perhaps other blood cells, to bind to the endothelium. In some cases, the PAF produced by endothelial cells appears to be a sufficient stimulus for this binding, but in other circumstances it appears to act in concert with a glycoprotein, GMP-140. The synthesis and expression of PAF are tightly regulated under normal conditions, but can be induced by bacterial toxins and oxidants, which in vivo might result in vascular damage and thrombosis.

A Comparison of Ectonucleotidase Activities on Vascular Endothelial and Smooth Muscle Cellsa

Abstract: Extracellular adenine nucleotides can be sequentially hydrolyzed to yield adenosine by ectoenzymes found on many cell types.' Because the extent of phosphorylation can profoundly modify the physiologic effects of extracellular adenine nucleotides, we thought it highly likely that the regulation of the time course of their hydrolysis would be complex and would be tuned to serve different purposes in different locations. Regulation of the rates of nucleotide hydrolysis, together with an array of cell-specific responses to adenine nucleotides and adenosine, provides a rich network of regulatory elements with which to integrate the time course of cell and tissue response during crisis or signaling. We have investigated the whole time course of hydrolysis of ATP, ADP, and AMP by cultured endothelial cells and smooth muscle cells from pig aorta.*,' Cells were grown attached to polystyrene beads. Cell-coated beads were loaded into chromatography columns, and substrates were perfused over them (FIG. 1 ). In single-pass perfusion, this gives an incubation volume-to-cell-surface ratio close to that observed in intact issue. When substrates are recirculated over the cells, the volumeto-surface ratio is comparable to that found at the surface of large blood vessels. We found that endothelial cells and smooth muscle cells differ strikingly in their means of regulation of the rate of adenosine appearance from ATP or ADP.

Effect of growth factors on human vascular endothelial cell prostacyclin production.

Abstract: Prostacyclin (PGI2) is an antithrombotic factor, which may prevent the initiation and the complications of arteriosclerosis. The most important site of PGI2 production is the vascular endothelium, but little is known about how this process is regulated. In this connection, there is special interest in the roles of various growth factors released from platelets, macrophages, vascular smooth muscle cells, and the endothelial cells themselves. We investigated the effects of transforming growth factor-beta (TGF-beta), platelet-derived growth factor (PDGF), and acidic and basic fibroblast growth factors (aFGF and bFGF) on the PGI2 production of cultured human umbilical vein endothelial cells by measuring the stable metabolite of PGI2, 6-keto-prostaglandin F1 alpha, by radioimmunoassay. TGF-beta induced dose- and time-dependent stimulation of PGI2 production. The lowest stimulatory concentration of TGF-beta was 0.1 ng/ml, and the maximal response, a 2.1-fold rise, was obtained with 1.0 ng/ml. The effect of TGF-beta lasted 48 hours and was blocked by inhibitors of transcription, translation, and cyclooxygenase. Maximal stimulation by TGF-beta was enhanced by epidermal growth factor. PDGF and bFGF had no effect on PGI2 production, but aFGF inhibited it. This is the first demonstration that TGF-beta enhances PGI2 production by human vascular cells, and this phenomenon may be part of negative feedback mechanisms that prevent thrombosis and arteriosclerosis.

Endothelial Control of Vascular Tone and Growth

Abstract: Endothelial cells play an important regulatory role in the circulation as a physical barrier and as a source of a variety of regulatory substances. Endothelium-derived nitric oxide and prostacyclin are released in response to physical stimuli, hormones and platelet-derived substances and induce vascular relaxation and inhibition of platelet function. Certain substances can evoke a hyperpolarization of smooth muscle cells. In addition, endothelial cells can release several contracting factors (i.e. endothelin, thromboxane A2, angiotensin II, superoxide and unidentified endothelium-derived contracting factors), at least under certain conditions. Endothelial cells are also a source of growth inhibitors and promoters, such as heparin and heparin sulphates, platelet-derived growth factor and thrombospondin. Several vasoactive substances produced by the endothelium, such as nitric oxide, endothelin and angiotensin II may also play a role in the regulation of vascular growth. Thus, the endothelial layer can regu...

Heparin-endothelial cell interactions.

Abstract: Recent observations have revealed that heparin influences endothelial cell proliferation in a number of ways unrelated to its anticoagulant properties. A majority of the nonanticoagulant actions of he

Scatter factor regulates vascular endothelial cell motility.

Abstract: Scatter factors (SFs) are mesenchymal cellderived cytokines which stimulate epithelial motility. SF purified from ras-transformed 3T3 cell supernatants markedly stimulated vascular endothelial cell migration at < 100 pM. Preliminary studies suggest endothelial lines with cobblestone (epithelioid) morphology respond to SF, while those lines with elongated cells do not respond. SFs may play roles in development and tissue repair.

Platelet-derived Endothelial Cell Growth Factor

Abstract: Platelet-derived endothelial cell growth factor (PD-ECGF) is a 45 kDa single chain polypeptide, which stimulates the DNA synthesis and chemotaxis of endothelial cells in vitro and angiogenesis in vivo. Purification from human platelets and cDNA cloning from a human placental cDNA library, revealed that PD-ECGF is a novel type of peptide without sequence similarity to hitherto known proteins. PD-ECGF is present in human platelets and placenta, and is produced by certain normal and transformed cultured cells; it lacks a hydrophobic leader sequence and most of the protein remains inside the producer cells. Analysis of PD-ECGF produced by cultured cells, revealed that it contains nucleotide(s) covalently bound to serine residues. The in vivo function of PD-ECGF is not known; its target cell specificity and tissue distribution suggest roles in angiogenesis of the placenta and in the maintenance of the integrity of the endothelial cell layer of blood vessels. PD-ECGF may have a clinical utility in the stimulation of wound healing and re-endothelialization of vessels.

Heparin-binding (fibroblast) growth factors type one and two genes are co-expressed in proliferating normal human vascular endothelial and smooth muscle cells in culture.

Abstract: Complimentary ribonucleic acid (cRNA) probes were used to detect expression of the genes for heparin binding (fibroblast) growth factor type one (HBGF-1) and two (HBGF-2) in cultured endothelial and smooth muscle cells from normal human blood vessels. Hybridizationin situ revealed that transcripts for both HBGF-1 and HBGF-2 are expressed in endothelial cells from both umbilical vein and aorta. Relative intensity of radioactive grains suggest that HBGF-1 gene expression may exceed HBGF-2 expression in aortic smooth muscle cells. Collective expression of both HBGF-1 and HBGF-2 in smooth muscle cells may exceed that in endothelial cells.

Selected cytokines promote the synthesis of platelet-activating factor in vascular endothelial cells: comparison between tumor necrosis factor alpha and beta and interleukin-1.

Abstract: Tumor necrosis factor (TNF alpha and TNF beta) and interleukin-1 (IL-1) are mediators of immunity and inflammation that induce different, but partially overlapping responses in human endothelial cells (HEC). We compared the effect of purified recombinant human TNF alpha, TNF beta and IL-1 on the production of platelet-activating factor (PAF) in HEC. After 30-60 min of treatment with TNF alpha or TNF beta, HEC produce and partially release considerable amounts of PAF, which reach a maximum after 4-6 h. In HEC treated with IL-1 PAF production is detectable after 2 h and peaks at 8-12 h. More than twice as much PAF is produced in response to optimal concentrations of TNF alpha than in response to TNF beta or IL-1. However, PAF synthesis is stimulated by lower molar concentrations of IL-1 than TNF alpha and TNF beta. The ability to induce PAF synthesis in HEC seems to be restricted to these three cytokines, as shown by negative results obtained with other cytokines that activate HEC (interferons, granulocyte- and granulocyte-macrophage colony-stimulating factor, epithelial growth factor, fibroblast growth factor, transforming growth factor beta), or participate in the inflammatory process (IL-6, platelet-derived growth factor).

LPS-stimulated bovine aortic endothelial cells produce IL-1 and IL-6 like activities.

Abstract: Vascular endothelium is known to closely interact with leukocytes and immunocompetent cells. We report here that cultured bovine aortic endothelial cells (BAEC) synthesize both interleukin 1 (IL-1) and interleukin 6 (IL-6) like activities in response to bacterial lipopolysaccharide stimulation. Our results agree with previous data obtained from human venous endothelia and support the concept that IL-1 and IL-6 synthesis are properties common to endothelial cells from different vascular beds. The IL-1 activity was measured by murine thymocyte proliferation assay and by an indirect bioassay using NOB1 cells, which evidenced higher IL-1 amounts than the former. This discrepancy appeared to be partly due to the simultaneous production of one or more inhibitor(s) of the thymocyte proliferation by BAEC. The IL-6 assay was performed with the murine hydridoma cell line B9. In other respects, the cyclooxygenase inhibitor indomethacin enhanced the IL-1 like production, but was ineffective on IL-6 like production. The present study provides additional evidence that endothelial cells from large arteries may also participate in inflammatory and immunological processes.

Retinoid-induced potentiation of epidermal growth factor mitogenic effect on corneal endothelial cells.

Abstract: Epidermal growth factor (EGF) is mitogenic for bovine corneal endothelial cells in culture. Pretreatment with either retinoic acid or the synthetic analog CBS-211 A ((E)-4-[2-(2-isopropyl-5-thienyl)propenyl]benzoic acid) at 10(-8)-10(-6) M enhanced the EGF effect. This potentiating effect of retinoids contrasts with their intrinsic activity, which results in cell growth inhibition in the absence of growth factor. The present data emphasize the previously reported beneficial effect of retinoic acid on corneal endothelium wound healing. This effect could be related to the potentiation of endogenous growth factors and further underlines the importance of retinoids in the medical treatment of corneal endothelial lesions.

P2‐Purinergic Receptors on Vascular Endothelial Cells

Abstract: ATP and ADP, via P,, receptors, stimulate the release of nitric oxide’ and of prostacyclin *.’ from aortic endothelial cells and increase their rate of proliferation? These actions might have a physiological importance in the interaction between platelets and the vascular endothelium. The release of prostacyclin will limit the extent of platelet aggregation following a lesion of the endothelium, while the mitogenic effect will accelerate the repair of that lesion. Bovine aortic endothelial cells (BAECs) provided a useful model to elucidate the transduction mechanisms associated with PZy receptors. The occupancy of these receptors induces the hydrolysis of several phospholipids by various phospholipases, generating different second messengers. These responses have different time courses and are triggered by distinct mechanisms (FIG. 1). ATP and ADP induce a rapid and transient accumulation of inositol trisphosphate ( lP3), reflecting the hydrolysis of phosphatidylinositol bisphosphate (PIP,) by phospholipase C (FIG. lA).’ The rise of cytoplasmic Ca2+ that results6 is responsible for a burst of prostacyclin release, probably via the activation of a Ca2+-dependent phospholipase A,.’ The coupling of the P,, receptors and the phospholipase C seems to involve a GTP-binding protein (FIG. lC).* ATP and ADP also induce a sustained increase of the choline level inside endothelial cells (FIG. lB), an increase likely to result from the activation of phospholipase D, which hydrolyzes phosphatidylcholine into phosphatidic acid and choline? Phosphatidic acid might play a role in the mitogenic effect of ATP.” Depletion of protein kinase C by a prolonged exposure to phorbol 12-myristate 13-acetate abolished the ATP-stimulated release of choline metabolites (FIG. 1D). This indicates that the activation of protein kinase C by diacylglycerol released from PIP, plays a crucial role in the stimulation of phospholipase D.’