Induction of endothelial cell proliferation by recombinant and microparticle-tissue factor involves beta1-integrin and extracellular signal regulated kinase activation.
OBJECTIVE
Increased levels of circulating tissue factor (TF) in the form of microparticles increase the risk of thrombosis. However, any direct influence of microparticle-associated TF on vascular endothelial cell proliferation is not known. In this study, the influence of recombinant and microparticle-associated TF on endothelial cell proliferation and mitogen-activated protein kinase signaling mechanisms was examined.


RESULTS
Incubation of human coronary artery endothelial cells with lipidated recombinant full-length TF, or TF-containing microparticles (50 to 200 pmol/L TF), increased the rate of cell proliferation and induced phosphorylation of extracellular signal regulated kinase 1 in a TF-dependent manner. Inhibition of extracellular signal regulated kinase 1/2 using PD98059 or extracellular signal regulated kinase 1/2 antisense oligonucleotides or inhibition of c-Jun N-terminal kinase reduced recombinant TF-mediated cell proliferation. PD98059 also reduced cell proliferation in response to TF-containing microparticles. Inclusion of FVIIa (5 nmol/L) and FXa (10 nmol/L) or preincubation of cells with an inhibitory anti-FVIIa antibody had no additional influence on TF-mediated cell proliferation. However, preincubation of exogenous TF with a beta1-integrin peptide (amino acids 579 to 799) reduced TF-mediated proliferation.


CONCLUSIONS
High concentrations of recombinant or microparticle-associated TF stimulate endothelial cell proliferation through activation of the extracellular signal regulated kinase 1/2 pathway, mediated through a novel mechanism requiring the interaction of exogenous TF with cell surface beta1-integrin and independent of FVIIa.
Collier
Mary E W
ME
Biomedical Section, Department of Biological Sciences, University of Hull, Hull HU6 7RX, United Kingdom.
Ettelaie
Camille
C
D017209:Apoptosis; D049109:Cell Proliferation / Q000187:drug effects; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D004789:Enzyme Activation; D015942:Factor VIIa / Q000378:metabolism; D015951:Factor Xa / Q000378:metabolism; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013925:Thromboplastin / Q000378:metabolism*; D013997:Time Factors
D019012:Integrin beta1; D016376:Oligonucleotides, Antisense; D047428:Protein Kinase Inhibitors; D011994:Recombinant Proteins; D013925:Thromboplastin; C103587:recombinant FVIIa; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D015942:Factor VIIa; D015951:Factor Xa