Affiliations: Laboratoire de Recherche sur les Biomatériaux et les Biotechnologies (LR2B), Université du Littoral Côte d'Opale, rue du Dr Calot, Berck sur mer, France | Equipe Matériaux ENSAM, Laboratoire de Métallurgie physique, CNRS URA234, bd Louis XIV, Lille, France
Note: [] Corresponding author: K. Anselme, Laboratoire de Recherche sur les Biomatériaux et les Biotechnologies (LR2B), Université du Littoral Côte d'Opale, 52 rue du Dr Calot, 62608 Berck sur mer, France. Tel./Fax: +33 321 89 20 29; E‐mail: [email protected].
Abstract: Intercellular adhesions are known to play an important role in differentiation of osteoblasts and in the development of bone tissue architecture. However, to our knowledge, they have never been studied during the formation of bone tissue in contact with a biomaterial surface. In an in vitro kinetic study, we followed the expression of proteins involved in cell–cell interactions (β‐catenin), in cell–material interactions (vinculin) and in cytoskeleton (actin) of human osteoblastic cells cultured on grooved titanium‐based substrates during 1, 2, 4, 6, 24, 48, and 72 hours. The human osteoblasts aligned themselves in the 150 μm wide grooves only after 24 hours. The distribution of vinculin‐positive focal contacts, actin cytoskeleton and β‐catenin positive‐adherens junctions was not significantly influenced by the cell alignment. β‐catenin‐positive adherens junctions were expressed by human osteoblasts as soon as 1 hour after inoculation. At this time, they showed a patch‐like aspect along cytoplasmic processes in contact with an underlying or an adjacent cell. After 2 hours, the patches were more and more numerous underlining the connections between cells. After 4 hours and more, the patches were organised in a parallel arrangement perpendicular to the two connected cells forming a “zip‐like” aspect. Additionally, using double immuno‐staining, we demonstrated that sometimes β‐catenin and vinculin appeared co‐localised and sometimes not. The linkage of catenin/cadherin complex and vinculin‐positive focal contacts with actin filaments may explain this apparent co‐localisation.
Keywords: Adhesion, β‐catenin, vinculin, osteoblast, titanium, actin, human
