title: Laminin synthesis and the adhesion characteristics of immortalized human corneal epithelial cells to laminin isoforms.
abstract: We have studied the synthesis of laminins (Ln) and determined the specific integrins mediating the adhesion of immortalized human corneal epithelial cells to mouse Ln-1, and human Lns-5 and -10. Immunofluorescence microscopy of the cells demonstrated integrin alpha(2), alpha(3), alpha(6), beta(1)and beta(4)subunits, integrins alpha(6)and beta(4)being found in a typical 'leopard-skin' like manner. Immunoprecipitation studies showed that the cells produced alpha 3, beta 3 and gamma 2 chains of Ln-5, but not Lns-1 or -10. In culture Ln-5 was found as small plaques beneath the adhering cells within 1 hr, while in 4 hr widely spread Ln-5 plaques were observed in colocalization with beta(4)integrin subunit. By using a quantitative cell adhesion assay and function-blocking monoclonal antibodies we showed that integrin beta(1)subunit plays a role in mediating corneal epithelial cell adhesion to mouse Ln-1. However, none of the available function-blocking antibodies to integrin alpha-subunits inhibited the adhesion. Integrin alpha(3)beta(1)complex mediated the adhesion of corneal epithelial cells to human Lns-5 and -10. Integrin complex alpha(3)beta(1), as well as laminin alpha(3)chain, was also shown to mediate cell adhesion to newly produced endogenous Ln-5. The present results show that integrin alpha(3)beta(1)complex mediates the adhesion of corneal epithelial cells to Lns-5 and -10, while a yet unknown integrin alpha subunit appears to play a role in the adhesion to Ln-1. The results also show that among corneal basement membrane laminins, Ln-5 is synthetized by epithelial cells while Ln-10 may be a product of keratocytes.
authors.affiliation: Department of Anatomy, Institute of Biomedicine, University of Helsinki, Helsinki, Finland. hasenson@hytti.uku.fi
authors.forename: S
authors.initials: S
authors.lastname: Filenius
authors.forename: M
authors.initials: M
authors.lastname: Hormia
authors.forename: J
authors.initials: J
authors.lastname: Rissanen
authors.forename: R E
authors.initials: RE
authors.lastname: Burgeson
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
authors.forename: K
authors.initials: K
authors.lastname: Araki-Sasaki
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
authors.forename: I
authors.initials: I
authors.lastname: Virtanen
authors.forename: T
authors.initials: T
authors.lastname: Tervo
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D002448:Cell Adhesion; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D019573:Epithelium, Corneal / Q000166:cytology / Q000502:physiology*; D006801:Humans; D016023:Integrins / Q000378:metabolism; D007797:Laminin / Q000502:physiology*; D051379:Mice; D011233:Precipitin Tests; D020033:Protein Isoforms
chemical_list: D000911:Antibodies, Monoclonal; D016023:Integrins; D007797:Laminin; D020033:Protein Isoforms