Functions of the fibrinolytic system in human Ito cells and its control by basic fibroblast and platelet-derived growth factor.
During liver fibrogenesis, hepatic stellate cells (HSC) proliferate and migrate under the influence of growth factors, including platelet-derived growth factor (PDGF) and basic-fibroblast growth factor (b-FGF). The plasminogen activation system regulates extracellular matrix (ECM) catabolism and cell movement. We evaluated the expression and biological functions of the plasminogen activation system in human HSC and its interaction with PDGF and b-FGF. Urokinase-plasminogen activator receptors (u-PAR) were measured by radioligand binding, cell cross-linking, immunoassay, and RNAse protection assay. u-PA and plasminogen activator inhibitors (PAIs) expression and activities were analyzed by zymography, immunoassay, and RNase protection assay. Cell migration and proliferation, studied in Boyden chambers and by microscopic counting, were evaluated after the addition of PDGF, b-FGF, and blockade with anti-u-PA, anti-u-PAR antibodies, and antisense oligodeoxynucleotides (aODN) against u-PAR mRNA. We have shown that HSC produce u-PAR, u-PA, and PAI-1. PDGF and b-FGF up-regulate u-PA and u-PAR, but not PAI-1, and exogenous addition of u-PA stimulates HSC proliferation, chemotaxis, and chemoinvasion. Inhibition of u-PA/u-PAR with antibodies against u-PA or u-PAR and with u-PAR aODN inhibit the proliferative, chemotactic, and chemoinvasive activity of PDGF and b-FGF. These findings indicate that u-PA and u-PAR are required for the mitogenic and chemoinvasive activity of PDGF and b-FGF on HSC.
Fibbi
G
G
Institute of General Pathology, Department of Clinical Pathophysiology, University of Florence, Florence, Italy.
Pucci
M
M
Grappone
C
C
Pellegrini
G
G
Salzano
R
R
Casini
A
A
Milani
S
S
Del Rosso
M
M
D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005109:Extracellular Matrix / Q000502:physiology; D005342:Fibrinolysis / Q000187:drug effects / Q000502:physiology*; D016222:Fibroblast Growth Factor 2 / Q000502:physiology*; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010960:Plasminogen Activators / Q000494:pharmacology; D010982:Platelet-Derived Growth Factor / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D055293:Receptors, Urokinase Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism / Q000494:pharmacology
D006133:Growth Substances; D016376:Oligonucleotides, Antisense; C524898:PLAUR protein, human; D010982:Platelet-Derived Growth Factor; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D016222:Fibroblast Growth Factor 2; D010960:Plasminogen Activators; D014568:Urokinase-Type Plasminogen Activator