lntegrin expression on epiphyseal mouse chondrocytes in monolayer culture

Abstract

The expression of al-, a3-, av- and a5B1- integrins and their specific ligand binding were investigated in monolayer cultures of chondrocytes from 17-day-old mouse embryos using morphological and immunomorphological methods. After a 1-day culture period av-, a3- and a5B1-integrins were observed on these cells. Immunoelectronmicroscopic investigation revealed localization predominantly in the contact areas with extracellular structures on the cell surface. alintegrin could not be demonstrated on chondrocytes. After a 5-day culture period the number of fibroblastlike cells with a l - , av- and a5B1-integrins had increased. a3-integrin was hardly recognizable on these cells. Collagen type 1 and fibronectin could be shown as ligands on the cell surface. The number of chondrocytes with collagen type 11 on their surface continuously decreased. a3-integrin is obviously responsible for the binding of collagen type 11, and al-integrin for the binding of collagen type 1. Therefore, it can be concluded that the changes of chondrocytes to fibroblast- like cells in monolayer culture are accompanied by changes of integrin genes.