Specific roles of the αVβ1, αVβ3 and αVβ5 integrins in avian neural crest cell adhesion and migration on vitronectin

Abstract

To identify potentially important extracellular matrix adhesive molecules in neural crest cell migration, the possible role of vitronectin and its corresponding integrin receptors was examined in the adhesion and migration of avian neural crest cells in vitro. Adhesion and migration on vitronectin were comparable to those found on fibronectin and could be almost entirely abolished by antibodies against vitronectin and by RGD peptides. Immunoprecipitation and immunocytochemistry analyses revealed that neural crest cells expressed primarily the αVβ1, αVβ3 and αVβ5 integrins as possible vitronectin receptors. Inhibition assays of cellular adhesion and migration with functionperturbing antibodies demonstrated that adhesion of neural crest cells to vitronectin was mediated essentially by one or more of the different αV integrins, with a possible preeminence of αVβ1, whereas cell migration involved mostly the αVβ3 and αVβ5 integrins. Immunofluorescence labeling of cultured motile neural crest cells revealed that the αV integrins are differentially distributed on the cell surface. The β1 and αV subunits were both diffuse on the surface of cells and in focal adhesion sites in association with vinculin, talin and α-actinin, whereas the αVβ3 and αVβ5 integrins were essentially diffuse on the cell surface. Finally, vitronectin could be detected by immunoblotting and immunohistochemistry in the early embryo during the ontogeny of the neural crest. It was in particular closely associated with the surface of migrating neural crest cells. In conclusion, our study indicates that neural crest cells can adhere to and migrate on vitronectin in vitro by an RGD-dependent mechanism involving at least the αVβ1, αVβ3 and αVβ5 integrins and that these integrins may have specific roles in the control of cell adhesion and migration.