DIFFERENTIAL EXPRESSION OF THE 2 VEGF RECEPTORS FLT AND KDR IN PLACENTA AND VASCULAR ENDOTHELIAL-CELLS

Vascular endothelial growth factor (VEGF) is a newly identified growth and permeability factor with a unique specificity for endothelial cells. Recently the fit-encoded tyrosine kinase was characterized as a receptor for VEGF. A novel tyrosine kinase receptor encoded by the KDR gene was also found to bind VEGF with high affinity when expressed in CMT-3 cells. Screening for fit and KDR expression in a variety of species and tissue-derived endothelial cells demonstrates that fit is predominantly expressed in human placenta and human vascular endothelial cells. Placenta growth factor (PlGF), a growth factor significantly related to VEGF, is coexpressed with fit in placenta and human vascular endothelial cells. KDR is more widely distributed and expressed in all vessel-derived endothelial cells. These data demonstrate that cultured human endothelial cells isolated from different tissues express both VEGF receptors in relative high levels and, additionally, that all investigated nonhuman endothelial cells in culture are also positive for KDR gene expression. (C) 1994 Wiley-Liss, Inc.