The vascular endothelial growth factor receptor Flt-1 mediates biological activities. Implications for a functional role of placenta growth factor in monocyte activation and chemotaxis.
Two distinct receptors for vascular endothelial growth factor (VEGF), the tyrosine kinase receptors Flt-1 and Flk-1/KDR, have been described. In this study we show that monocytes, in contrast to endothelium, express only the VEGF receptor Flt-1, and that this receptor specifically binds also the VEGF homolog placenta growth factor (PlGF). Both VEGF and PlGF stimulate tissue factor production and chemotaxis in monocytes at equivalent doses. In contrast, endothelial cells expressing both the Flt-1 and the Flk-1/KDR receptors produce more tissue factor upon stimulation with VEGF than after stimulation with PlGF. Neutralizing antibodies to the KDR receptor reduce the VEGF-stimulated tissue factor induction in endothelial cells to levels obtained by stimulation with PlGF alone, but do not affect PlGF-induced tissue factor induction in endothelial cells nor the VEGF-dependent tissue factor production in monocytes. These findings strongly suggest Flt-1 as a functional receptor for VEGF and PlGF in monocytes and endothelial cells and identify this receptor as a mediator of monocyte recruitment and procoagulant activity.
Clauss
M
M
Abteilung für Molekulare Zellbiologie, Max-Planck-Institut für Physiologische und Klinische Forschung, D-61231 Bad Nauheim, Germany.
Weich
H
H
Breier
G
G
Knies
U
U
Röckl
W
W
Waltenberger
J
J
Risau
W
W
D000818:Animals; D001483:Base Sequence; D001667:Binding, Competitive; D002634:Chemotaxis, Leukocyte / Q000502:physiology*; D016228:Endothelial Growth Factors / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D006801:Humans; D008222:Lymphokines / Q000378:metabolism; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism*; D000072483:Placenta Growth Factor; D011257:Pregnancy Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D017978:Receptors, Growth Factor / Q000378:metabolism*; D040262:Receptors, Vascular Endothelial Growth Factor; D013552:Swine; D013925:Thromboplastin / Q000096:biosynthesis*; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; C000608036:PGF protein, human; D011257:Pregnancy Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D000072483:Placenta Growth Factor; D013925:Thromboplastin; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D040281:Vascular Endothelial Growth Factor Receptor-1