Coagulation factor Xa stimulates platelet-derived growth factor release and mitogenesis in cultured vascular smooth muscle cells of rat.
The mitogenic effect of activated coagulation factor X (factor Xa) was examined in cultured aortic smooth muscle cells (VSMC) from Wistar-Kyoto rats (WKY). Factor Xa stimulated DNA synthesis and cell growth in VSMC, not through the phospholipase C-protein kinase C pathway because increase of inositol monophosphate (IP) accumulation and intracellular Ca2+ concentration was not observed, but probably via the PDGF receptor tyrosine kinase pathway since the pathway's components, Ras, Raf-1, MAPK (both 42 and 44 kD), and the transcription factors, c-Fos and c-Jun, were activated. These appeared to be effected by the serine protease activity of factor Xa, since in the presence of serine protease inhibitors such as PMSF, leupeptin, benzamidine, TAP anticoagulant, and TLCK, the latter three being specific inhibitors of the factor Xa, active site, the effects were completely blocked. Anti-factor Xa mAb, 5224, which specifically negated the activity of factor Xa, also inhibited completely the mitogenic effect of factor Xa, but not that of thrombin. Addition of PDGF did not affect the effect of factor Xa, which, however, was inhibited by anti-PDGF-AB antibody. This observation and the activation of PDGF receptor tyrosine kinase pathway suggested that the factor Xa might exert its effect via PDGF-like function. Direct measurement confirmed that factor Xa stimulated the release of PDGF from VSMC. Factor Xa, therefore, exerts serine protease activity on VSMC, causing somehow the release of PDGF, that in turn acts on the PDGF receptor tyrosine kinase; the pathway is then turned on, leading eventually to DNA synthesis and cell proliferation.
Ko
F N
FN
Pharmacological Institute, College of Medicine, National Taiwan University, Taipei.
Yang
Y C
YC
Huang
S C
SC
Ou
J T
JT
D000818:Animals; D019138:Antibodies, Blocking / Q000276:immunology; D001011:Aorta / Q000166:cytology; D015153:Blotting, Western; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D015951:Factor Xa / Q000276:immunology / Q000494:pharmacology*; D005434:Flow Cytometry; D015151:Immunoblotting; D020930:MAP Kinase Kinase Kinases; D008954:Models, Biological; D009130:Muscle, Smooth / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D051381:Rats; D017479:Receptors, Platelet-Derived Growth Factor / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D018631:ras Proteins / Q000378:metabolism
D019138:Antibodies, Blocking; D010982:Platelet-Derived Growth Factor; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D015842:Serine Proteinase Inhibitors; D004247:DNA; D011505:Protein-Tyrosine Kinases; D017479:Receptors, Platelet-Derived Growth Factor; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020930:MAP Kinase Kinase Kinases; C087095:insulin-stimulated MEK kinase; D015951:Factor Xa; D018631:ras Proteins