Tissue factor pathway inhibitor-2 is upregulated by vascular endothelial growth factor and suppresses growth factor-induced proliferation of endothelial cells.
OBJECTIVE
The purpose of this study is to investigate the expression and regulation of type-2 tissue factor pathway inhibitor (TFPI-2) in endothelial cells, as well as the regulation of human endothelial cell (EC) function by TFPI-2.


RESULTS
Real-time polymerase chain reaction (PCR) and Western blot analysis revealed that vascular endothelial growth factor (VEGF) induced both time- and dose-dependent increase in TFPI-2 mRNA and protein expression in endothelial cells. TFPI-2 mRNA expression was also significantly upregulated by IL-1beta, and modestly increased by both tumor necrosis factor (TNF)-alpha and fibroblast growth factor (FGF)-2, but not placental growth factor (PlGF). VEGF upregulation of TFPI-2 was dramatically reduced by inhibition of the MEK pathway. Administration of TFPI-2 protein suppressed both VEGF and FGF-2 stimulation of EC proliferation in a dose-dependent manner. A recombinant preparation of the first Kunitz-type domain of TFPI-2 (KD1) did not suppress growth factor stimulation of EC proliferation, suggesting a mechanism distinct from the proteinase inhibitory activity of TFPI-2. Exogenously added TFPI-2 protein suppressed VEGF-induced EC migration in 2 different assays. Recombinant wt-KD1 or the R24K mutant of KD1, but not the R24Q mutant, dramatically suppressed VEGF-induced EC migration. TFPI-2 protein, but not recombinant KD1, blocked VEGF-induced activation of both Akt and ERK1/2 in ECs. At higher doses, TFPI-2 protein blocked VEGFR2 activation.


CONCLUSIONS
Our data suggest that VEGF-upregulation of TFPI-2 expression in endothelial cells may represent a mechanism for negative feedback regulation and modulation of its pro-angiogenic action on endothelial cells. TFPI-2, or derivatives of TFPI-2, may be novel therapeutics for treatment of angiogenic disease processes.
Xu
Zhenhua
Z
Department of Ophthalmology, The Wilmer Ophthalmological Institute, The Johns Hopkins University School of Medicine, 1550 Orleans Street, Baltimore, MD 21231, USA.
Maiti
Debasish
D
Kisiel
Walter
W
Duh
Elia J
EJ
D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D053583:Interleukin-1beta / Q000494:pharmacology; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*
D006023:Glycoproteins; D053583:Interleukin-1beta; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C021240:tissue-factor-pathway inhibitor 2; D016222:Fibroblast Growth Factor 2; D040262:Receptors, Vascular Endothelial Growth Factor; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D020930:MAP Kinase Kinase Kinases