Expression of transmembrane 4 superfamily (TM4SF) proteins and their role in hepatic stellate cell motility and wound healing migration.
OBJECTIVE
Migration of activated hepatic stellate cells (HSC) is a key event in the progression of liver fibrosis. Little is known about transmembrane proteins involved in HSC motility. Tetraspanins (TM4SF) have been implicated in cell development, differentiation, motility and tumor cell invasion. We evaluated the expression and function of four TM4SF, namely CD9, CD81, CD63 and CD151, and their involvement in HSC migration, adhesion, and proliferation.


RESULTS
All TM4SF investigated were highly expressed at the human HSC surface with different patterns of intracellular distribution. Monoclonal antibodies directed against the four TM4SF inhibited HSC migration induced by extracellular matrix proteins in both wound healing and haptotaxis assays. This inhibition was independent of the ECM substrates employed (collagen type I or IV, laminin), and was comparable to that obtained by incubating the cells with an anti-beta1 blocking mAb. Importantly, cell adhesion was unaffected by the incubation with the same antibodies. Co-immunoprecipitation studies revealed different patterns of association between the four TM4SF studied and beta1 integrin. Finally, anti-TM4SF antibodies did not affect HSC growth.


CONCLUSIONS
These findings provide the first characterization of tetraspanins expression and of their role in HSC migration, a key event in liver tissue wound healing and fibrogenesis.
Mazzocca
Antonio
A
Dipartimento di Medicina Interna, Università degli Studi di Firenze, Viale Morgagni, 85, Florence, Italy. a.mazzocca@dfc.unifi.it
Carloni
Vinicio
V
Sciammetta
Silvia
S
Cordella
Claudia
C
Pantaleo
Pietro
P
Caldini
Anna
A
Gentilini
Paolo
P
Pinzani
Massimo
M
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D005434:Flow Cytometry; D022781:Hepatocytes / Q000737:chemistry / Q000166:cytology* / Q000502:physiology*; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism; D008103:Liver Cirrhosis / Q000473:pathology / Q000503:physiopathology; D008562:Membrane Glycoproteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D008565:Membrane Proteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D010980:Platelet Membrane Glycoproteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D060185:Tetraspanin 24; D060225:Tetraspanin 28; D060245:Tetraspanin 29; D060149:Tetraspanin 30; D014945:Wound Healing / Q000502:physiology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; C554715:CD151 protein, human; C554586:CD63 protein, human; C554798:CD81 protein, human; C554869:CD9 protein, human; D019012:Integrin beta1; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D010980:Platelet Membrane Glycoproteins; D060185:Tetraspanin 24; D060225:Tetraspanin 28; D060245:Tetraspanin 29; D060149:Tetraspanin 30; D004247:DNA