TF/FVIIa transactivate PDGFRbeta to regulate PDGF-BB-induced chemotaxis in different cell types: involvement of Src and PLC.
BACKGROUND
We have previously reported the potentiation of PDGF-BB-induced chemotaxis of fibroblasts, vascular smooth muscle cells, and endothelial cells by FVIIa. Here we studied the role of TF/FVIIa and the induced signaling pathways in regulation of chemotaxis of human monocytes, fibroblasts, and porcine aorta endothelial cells.


RESULTS
Human monocytes were obtained by using Ficoll-Paque gradient and the MACS system (for highly purified population), fibroblasts and PAE cells have been characterized previously. Inhibitors of selected signaling intermediates were used, and the effect of TF/FVIIa on the migratory response of all cells to chemotactic agents was analyzed. The induced signaling was studied by immunoprecipitation and Western blotting. TF/FVIIa complex selectively enhanced PDGF-BB-induced chemotaxis in a Src-family, PLC, and PAR-2-dependent manner. Using PAE cells we identified c-Src and c-Yes as the Src-family members activated by TF/FVIIa. We report for the first time the PAR-2 and Src family-dependent transactivation of PDGFRbeta by TF/FVIIa involving phosphorylation of a subset of PDGFRbeta tyrosines.


CONCLUSIONS
The described transactivation is a likely mechanism of TF/FVIIa-mediated regulation of PDGF-BB-induced chemotaxis. Similar behavior of 3 principally different cell types in our experimental setup may reflect a general function of TF in regulation of cell migration.
Siegbahn
Agneta
A
Department of Medical Sciences, Clinical Chemistry, Academic Hospital, SE-751 85 Uppsala, Sweden. agneta.siegbahn@medsci.uu.se
Johnell
Matilda
M
Nordin
Anna
A
Aberg
Mikael
M
Velling
Teet
T
D000818:Animals; D000077214:Becaplermin; D002478:Cells, Cultured; D002633:Chemotaxis / Q000502:physiology*; D042783:Endothelial Cells / Q000502:physiology; D015942:Factor VIIa / Q000502:physiology*; D005347:Fibroblasts / Q000502:physiology; D006801:Humans; D009000:Monocytes / Q000502:physiology; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D020574:Proto-Oncogene Proteins c-sis; D044464:Receptor, PAR-2 / Q000378:metabolism; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000502:physiology*; D015398:Signal Transduction; D013552:Swine; D013925:Thromboplastin / Q000502:physiology*; D015533:Transcriptional Activation / Q000502:physiology; D010738:Type C Phospholipases / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism*
D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D044464:Receptor, PAR-2; D000077214:Becaplermin; D013925:Thromboplastin; D020797:Receptor, Platelet-Derived Growth Factor beta; D019061:src-Family Kinases; D010738:Type C Phospholipases; D015942:Factor VIIa