Transforming growth factor beta-1 stimulates invasivity of hepatic stellate cells by engagement of the cell-associated fibrinolytic system.
The activation of hepatic stellate cells (HSC) during liver fibrogenesis has been shown to be mediated by paracrine and autocrine loops involving transforming growth factor-beta1 (TGF-beta1) as the main fibrogenic mediator secreted by activated macrophages, endothelial cells and liberated by disintegrated platelets. The cell-associated plasminogen activation system regulates extracellular matrix (ECM) catabolism and cell movement. We have studied whether TGF-beta1 could modulate the plasminogen activation system in human HSC and the role of such protease system in the activity of TGF-beta1 on HSC. Urokinase plasminogen activator receptors (u-PAR), u-PA and plasminogen activator inhibitor type 1 (PAI-1) were determined by immunoassay and RNase protection assay. Cell migration, evaluated either as chemotaxis or as chemoinvasion, was studied in Boyden chambers after addition of TGF-beta1, and inhibition with anti-u-PA and anti-u-PAR antagonists [antibodies against u-PA and u-PAR and antisense oligonucleotides (aODN) against u-PAR mRNA]. We have shown that TGF-beta1 is not mitogenic for HSC, while it is a powerful motogen either in chemotaxis or chemoinvasion assays. TGF-beta1 up-regulates the synthesis and expression of PAI-1, as well as u-PAR expression and exposure at the cell membrane, while it does not affect u-PA levels. TGF-beta1-dependent chemoinvasion of reconstituted basement membrane exploits the cell-associated plasminogen activation system, since it is blocked by monoclonal antibodies against u-PA and against various u-PAR domains, as well as by anti-u-PAR aODN. We have also observed a cumulative effect of TGF-beta1, b-FGF and PDGF in the invasion assay of HSC: in the presence of low amounts of TGF-beta1 the chemoinvasive activity of PDGF and bFGF is dramatically increased. Also this cooperation requires u-PAR and is inhibited by monoclonal antibodies against u-PAR domains I, II and III.
Fibbi
G
G
Department of Experimental Pathology and Oncology, University of Florence, Italy.
Pucci
M
M
D'Alessio
S
S
Grappone
C
C
Pellegrini
G
G
Salzano
R
R
Casini
A
A
Milani
S
S
Del Rosso
M
M
D000818:Animals; D002455:Cell Division; D002465:Cell Movement; D002478:Cells, Cultured; D003094:Collagen / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004797:Enzyme-Linked Immunosorbent Assay; D005342:Fibrinolysis; D016222:Fibroblast Growth Factor 2 / Q000096:biosynthesis; D006801:Humans; D007797:Laminin / Q000494:pharmacology; D008099:Liver / Q000166:cytology*; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D009361:Neoplasm Invasiveness; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis; D017434:Protein Structure, Tertiary; D011509:Proteoglycans / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D012260:Ribonucleases / Q000378:metabolism; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D053773:Transforming Growth Factor beta1; D014945:Wound Healing
D004338:Drug Combinations; D007797:Laminin; D016376:Oligonucleotides, Antisense; C524898:PLAUR protein, human; D010982:Platelet-Derived Growth Factor; C524899:Plaur protein, mouse; D011509:Proteoglycans; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; C508960:TGFB1 protein, human; C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D016222:Fibroblast Growth Factor 2; C059485:matrigel; D003094:Collagen; D012260:Ribonucleases