scholarly journals CD44 isoforms containing exon V3 are responsible for the presentation of heparin-binding growth factor.

1995 ◽  
Vol 128 (4) ◽  
pp. 687-698 ◽  
Author(s):  
K L Bennett ◽  
D G Jackson ◽  
J C Simon ◽  
E Tanczos ◽  
R Peach ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Growth Factors ◽  
Growth Factor ◽  
Binding Proteins ◽  
Vascular Endothelial Cells ◽  
Heparin Binding ◽  
Binding Studies ◽  
Cd44 Isoforms ◽  
Cultured Endothelial Cells ◽  
Alternatively Spliced

Glycosaminoglycan-modified isoforms of CD44 have been implicated in growth factor presentation at sites of inflammation. In the present study we show that COS cell transfectants expressing CD44 isoforms containing the alternatively spliced exon V3 are modified with heparan sulfate (HS). Binding studies with three HS-binding growth factors, basic-fibroblast growth factor (b-FGF), heparin binding-epidermal growth factor (HB-EGF), and amphiregulin, showed that the HS-modified CD44 isoforms are able to bind to b-FGF and HB-EGF, but not AR. b-FGF and HB-EGF binding to HS-modified CD44 was eliminated by pretreating the protein with heparitinase or by blocking with free heparin. HS-modified CD44 immunoprecipitated from keratinocytes, which express a CD44 isoform containing V3, also bound to b-FGF. We examined whether HS-modified CD44 isoforms were expressed by activated endothelial cells where they might present HS-binding growth factors to leukocytes during an inflammatory response. PCR and antibody-binding studies showed that activated cultured endothelial cells only express the CD44H isoform which does not contain any of the variably spliced exons including V3. Immunohistological studies with antibodies directed to CD44 extracellular domains encoded by the variably spliced exons showed that vascular endothelial cells in inflamed skin tissue sections do not express CD44 spliced variants. Keratinocytes, monocytes, and dendritic cells in the same specimens were found to express variably spliced CD44. 35SO4(-2)-labeling experiments demonstrated that activated cultured endothelial cells do not express detectable levels of chondroitin sulfate or HS-modified CD44. Our results suggest that one of the functions of CD44 isoforms expressing V3 is to bind and present a subset of HS-binding proteins. Furthermore, it is probable that HS-modified CD44 is involved in the presentation of HS-binding proteins by keratinocytes in inflamed skin. However, our data suggests that CD44 is not likely to be the proteoglycan principally involved in presenting HS-binding growth factors to leukocytes on the vascular cell wall.

IGFBP-3 binding to endothelial cells inhibits plasmin and thrombin proteolysis

2002 ◽  
Vol 282 (1) ◽  
pp. E52-E58 ◽  
Author(s):  
B. A. Booth ◽  
M. Boes ◽  
B. L. Dake ◽  
K. L. Knudtson ◽  
R. S. Bar
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Vascular Endothelial Cells ◽  
Binding Protein ◽  
Vascular Endothelial ◽  
Insulin Like Growth Factor ◽  
Heparin Binding ◽  
Binding Region ◽  
Factor Binding ◽  
Igfbp 3

Insulin-like growth factor-binding protein (IGFBP)-3 contains a highly basic COOH-terminal heparin-binding region, the P3 region, which is thought to be important in the binding of IGFBP-3 to endothelial cells. IGFBP-3 and IGFBP-4, and their chimeras IGFBP-34 and IGFBP-43, were treated with plasmin and with thrombin, proteases known to cleave IGFBP-3. IGFBP-3 was highly susceptible to plasmin, whereas IGFBP-4 was less so. Substitution of the P3 region for the P4 region in IGFBP-4 (IGFBP-43) increased the ability of the protease to digest IGFBP-43; substitution of the P4 region for the P3 region in IGFBP-3 (IGFBP-34) decreased the digestion of IGFBP-34. When 125I-labeled IGFBP-3 or125I-IGFBP-43 was first bound to vascular endothelial cells, subsequent proteolysis by either plasmin or thrombin was substantially inhibited. Proteolysis of125I-IGFBP-34 was not inhibited in the presence of endothelial cells. The P3 peptide was cleaved by plasmin but not by thrombin. We conclude that the P3 region is central to proteolysis of IGFBP-3 by plasmin and thrombin, processes which were inhibited by association of IGFBP-3 with endothelial cells.

scholarly journals Control of proliferation of human vascular endothelial cells. Characterization of the response of human umbilical vein endothelial cells to fibroblast growth factor, epidermal growth factor, and thrombin

1978 ◽  
Vol 77 (3) ◽  
pp. 774-788 ◽  
Author(s):  
D Gospodarowicz ◽  
KD Brown ◽  
CR Birdwell ◽  
BR Zetter
Keyword(s):  
Endothelial Cells ◽  
Growth Factors ◽  
Growth Factor ◽  
Vascular Endothelial Cells ◽  
Umbilical Vein ◽  
Physiological Role ◽  
Cell Types ◽  
Vascular Endothelial ◽  
Human Endothelial Cells ◽  
Epidermal Growth

Because the response of human endothelial cells to growth factors and conditioning agents has broad implications for our understanding of wound healing angiogenesis, and human atherogenesis, we have investigated the responses of these cells to the fibroblast (FGF) and epidermal growth factors (EGF), as well as to the protease thrombin, which has been previously shown to potentiate the growth response of other cell types of FGF and EGF. Because the vascular endothelial cells that form the inner lining of blood vessels may be expected to be exposed to high thrombin concentrations after trauma or in pathological states associated with thrombosis, they are of particular interest with respect to the physiological role of this protease in potentiating cell proliferation. Our results indicate that human vascular endothelial cells respond poorly to either FGF or thrombin alone. In contrast, when cells are maintained in the presence of thrombin, their proliferative response to FGF is greatly increased even in cultures seeded at a density as low as 3 cells/mm2. Human vascular endothelial cells also respond to EGF and thrombin, although their rate of proliferation is much slower than when maintained with FGF and thrombin. In contrast, bovine vascular endothelial cells derived from vascular territories as diverse as the bovine heart, aortic arch, and umbilical vein respond maximally to FGF alone and neither respond to nor bind EGF. Furthermore, the response of bovine vascular endothelial cells to FGF was not potentiated by thrombin, indicating that the set of factors controlling the proliferation of vascular endothelial cells could be species-dependent. The requirement of cultured human vascular endothelial cells for thrombin could explain why the human cells, in contrast to bovine endothelial cells, are so difficult to maintain in tissue culture. Our results demonstrate that by using FGF and thrombin one can develop cultures of human vascular endothelial cells capable of being passage repeatedly while maintaining a high mitotic index. The stock cultures used for these studies have been passed weekly with a split ratio of 1 to 10 and are currently in their 30th passage. These cultures are indistinguishable from earlier passages when examined for the presence of Weibel-Palade bodies or Factor VIII antigen. We conclude that the use of FGF and thrombin can prevent the precocious senescence observed in most human endothelial cells cultures previously described.

Growth Factors Produced By Cultured Human Vascular Endothelial Cells

1981 ◽  
Author(s):  
Ch Willems ◽  
G C B Astaldi ◽  
Ph G de Groot ◽  
M Janssen ◽  
M D Gonsalvez ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Protein Synthesis ◽  
Growth Factors ◽  
Growth Factor ◽  
Cultured Cells ◽  
Vascular Endothelial Cells ◽  
Human Lymphocytes ◽  
Hybridoma Cells ◽  
Thymidine Uptake ◽  
Vascular Endothelial

The growth of cells in culture is regulated by several as yet undefined growth factors which are normally present in serum and released by cultured cells in vitro. We have investigated media conditioned by cultured vascular human endothelial cells (HEC) and smooth muscle cells (SMC) derived from umbilical veins and expiants from umbilical cords respectively. Cell proliferation was measured by 3H thymidine uptake. The conditioned medium of confluent endothelial cells (HECS) contain(s) oneor more factors which inhibit the growth of nonconfluent endothelial cells and SMC. HECS derived from actively growing HEC as well as conditioned SMC medium were inactive. The growth factor(s) is (are) also present in serum free HECS and is released in a time dependant fashion at least up to 72 h. The release of HECS does not correlate with cell lysis, but our experiments indicate that protein synthesis is required for the generation of HECS. HECS contains also potent growth factor(s) for hybridoma cells particularly for xenogenetic hybridomas between mouse myeloma cells and human lymphocytes. HECS can substitute for feeder cells in cloning by limiting dilution of hybridoma cells. The growth of hybridoma cells is enhanced, both by a 24 h “pulse” with HEC as well as in its continuous presence during culture, indicating that the effect is based on delivering a growth signal to the cells. In preliminary experiments to characterize HECS, the following findings were observed, - HECS production requires protein synthesis in endothelial cells, - the activity is abolished by treatment with periodate, suggesting that sugar moieties are involved, - on gel filtration HECS activity is associated with a molecular weight of 20-30×103. These findings demonstrate that one or more growth factors are synthesized and released by vascular endothelial cells, a finding which underlines once more the pivotal role of the endothelium in biological systems.

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