Interactions of mammalian cells with collagen.

Isolated stationary cells recognize and adhere to immobilized extracellular matrix (ECM) components. These processes are mediated by specific receptor-ligand types of interaction. The formation of cell-ECM contacts influences subsequent cellular behaviour, such as the promotion of cell survival, epithelial cell polarization, and cell differentiation. The binding reaction between cells and collagen is discussed in this paper in terms of findings from studies with two cell systems, adult rat hepatocytes and rat cardiac myocytes. Isolated adult rat hepatocytes adhere to or bind laminin, fibronectin, heparan sulphate and collagen. We have characterized the interaction of hepatocytes with collagen and have isolated a glycoprotein fraction from rat liver membranes that contains collagen-binding components. The ability of rat cardiac myocytes to recognize ECM components depends on the state of cell maturation. Myocytes isolated from neonatal rats adhere to the interstitial collagens (types I-III), to collagen types IV and V, to fibronectin and to laminin. In contrast, myocytes isolated from adult rats bind effectively only to collagen type IV and laminin and bind much less effectively to fibronectin. Furthermore, antibodies raised against neonatal myocyte membranes inhibit the adhesion of both neonatal myocytes and hepatocytes to interstitial collagens, but antibodies raised against adult myocyte membranes lack these effects. These observations indicate that similar collagen-binding molecules are present on such diverse cells as hepatocytes and neonatal myocytes and that these components might be lost during cell maturation.