Laminin and fibronectin in cell adhesion: enhanced adhesion of cells from regenerating liver to laminin.

Abstract

Laminin, a basement membrane glycoprotein isolated from cultures of mouse endodermal cells and rat yolk sac carcinoma cells, promoted the attachment of liver cells obtained from regenerating mouse liver. Cells from normal mouse liver attached readily to dishes coated with fibronectin but attached poorly to surfaces coated with laminin. Both proteins efficiently promoted the attachment of cells from livers undergoing regeneration. After regeneration, the attachment to laminin returned to the low levels found in animals not subjected to partial hepatectomy but attachment to fibronectin remained high. Immunofluorescent staining of sections of normal liver with antilaminin revealed the presence of laminin in or adjacent to the walls of the bile ducts and blood vessels. After induction of regeneration by partial hepatectomy, increased amounts of laminin appeared in the sinusoidal areas. After carbon tetrachloride poisoning, staining for laminin was especially pronounced in the necrotic and postnecrotic areas around the central veins. This additional expression of laminin was transient. It reached a maximum around 5-6 days after the injury and then gradually disappeared. These findings show that laminin is an adhesive protein. The increase of laminin in regenerating liver and the adhesiveness of cells from such livers to laminin suggest a role for laminin in the maintenance ofa proper tissue organization during liver regeneration.

Do neurons in the vertebrate CNS migrate on laminin?

“…Fibronectin has some neurite-promoting activity in vitro, but this effect appears to be limited to neurones of the peripheral nervous system (Baron-Van Evercooren et al, 1982;Rogers et al, 1983). The remaining known connective tissue and basement membrane components investigated, such as type IV collagen, which is produced by Schwann-cells (Bunge et al, 1980) and proteoglycans, which are present in the brain in vivo (Aquino et al, 1984), do not influence neurite outgrowth (Carbonetto et al, 1983;Manthorpe et al, 1983 vations suggest, together with the reported transient induction (Terranova et al, 1980;Foidart et al, 1980;Carlsson et al., of laminin in astrocytes of adult rat brain after injury (Liesi et 1981), and has an adhesive function . Since al., 1984a), that laminin may also play a role in neuronal embryonic brain and the external granule cell layer of post-natal regeneration.…”

Laminin is induced in astrocytes of adult brain by injury.

“…Hepatocytes from regenerating liver show enhanced adhesion to laminin (Carlsson et al, 1981) and fibronectin is known to be present during the early stages of tissue repair (Vaheri et al, 1983). Glial cells are thought to guide axons during brain development (Sidman and Rakic, 1973;Silver et al, 1982) and brain injury causes both induction of GFAP-positive Laniinin in adult rat brain after injury astrocytes (Bignami and Dahl, 1974b) and secretion of a protein with neuronotrophic activity (Nieto-Sampedro et al, 1982).…”

Fibronectin isoforms in plasma membrane domains of normal and regenerating rat liver

“…During liver regeneration, especially when hepatocytes enter into a proliferative stage [2], the nature of the interactions between hepatocytes and extracellular matrix components also changes . This is illustrated by the decreased interaction of fibronectin and laminin with dividing hepatocytes [6].…”