Laminin is produced by early rat astrocytes in primary culture.

Abstract

The production of laminin by early rat astrocytes in primary culture was investigated by double immunoffuorescence staining for laminin and the gliat fibrillary acidic protein (GFAP), a defined astrocyte marker. In early cultures (3 d in vitro; 3 DIV) cytoplasmic laminin was detected in all the GFAP-positive cells which formed the major population (80%) of the nonneuronal cells present in cultures from 20-21-d embryonic, newborn, or 5-d-old rat brains. Monensin treatment (10 #M, 4 h) resulted in accumulation of laminin in the Golgi region, located using labeled wheat germ agglutinin. Laminin started gradually to disappear from the cells with the time in culture, was absent in starshaped, apparently mature astrocytes, but remained as pericellular matrix deposits. The disappearance of cellular laminin was dependent on the age of the animal and the time in culture so that it started earlier in cultures from 5-d-old rat brains (5 DIV) and approximately following the in vivo age difference in cultures from newborn (12 DIV) and embryonic (14 DIV) rat brains.Our results indicate that laminin is a protein of early astrocytes and also deposited by them in primary culture, thus suggesting a role for this glycoprotein in the development of the central nervous system.The development and migration of brain cells have been extensively studied (1-3), and the timing for the appearance of the glial fibriUary acidic protein, a defined astrocyte marker (4-6) both in brain and in primary culture, has been well documented (4,(7)(8)(9).In several studies on primary cultures the development of neurons and glial cells have been shown to closely follow the pattern of the in vivo development (8-13); tissue culture systems may thus serve as experimental models for central development and cell interactions (14,15).Laminin, one of the matrix glycoproteins (16), is present in all basement membranes so far investigated (16-18) and is produced by various epithelial cells in culture (16,19). It is also produced by mouse neuroblastoma Cells (20), in which its pattern of localization suggests a role for laminin as their adhesion protein) In adult mouse brain, laminin has been found only in connection with blood vessel wails (21), but little is known about the expression of laminin in normal developing cells of neuroectodermal origin. Fibronectin, the other major noncollagenous matrix glycoprotein, important in normal development of several types of cells (22, 23), has been demonLiesi, P. 1983. Laminin in cultured mouse C 1300 neuroblastoma cells: immunocytochemical localization by pre-and postembedding electron microscope procedures. J. Histochem. Cytochem. In press. 920 strated to be present in vessel walls in developing and adult rat brain (24). In primary brain cell cultures, fibronectin is thought to be due to mesenchymal cell contamination (25).In the present study, we used primary cultures from early rat brain to study the possible role of laminin for development of central cells of neuroectodermal origin. We demonstrate that lamin...

Discovery of a functional protein complex of netrin-4, laminin γ1 chain, and integrin α6β1 in mouse neural stem cells

“…In the olfactory system, astrocytic function may include tissue remodeling associated with mitosis and migration of other cells. Astrocyte production of laminin and other extracellular matrix components such as tenascin-C and chondroitin sulfate has been demonstrated under both normal and pathological conditions (29,37). To add further levels of complexity and diversity, there appear to be multiple subsets of GFAP-expressing astrocytes in the olfactory system, distinguished by whether or not they express surface markers such as vimentin and nestin (38,39).…”

“…Laminin is thought to be involved in the development of the brain (28) and in the regulation of NSC migration, expansion, and differentiation into neurons and astrocytes (29). Glial cells of mammalian brain produce a variant form of laminin composed only of ␤ and ␥ chains (30).…”

Laminin is induced in astrocytes of adult brain by injury.

“…This is also where fibronectin, the other major matrix glycoprotein, occurs in brain tissue (Schachner et al, 1978;Paetau et al, 1980). Recently, we detected laminin production by rat astrocytes in primary culture (Liesi et al, 1983a) and found that in cultured neuroblastoma cells the ultrastructural localization of laminin (Liesi, 1983) is compatible with a role for this glycoprotein in cell-to-cell and cellto-substratum interactions (Terranova et al, 1980;Ekblom et al, 1980;Liesi, 1983). Brain injury is known to exert a glial reaction that involves a conversion of the protoplasmic astrocytes of the gray matter into reactive astrocytes positive for glial fibrillary acidic protein (GFAP) (Bignami and Dahl, 1974b;Bignami et al, 1980).…”

Up-regulation of the integrin alpha 1/beta 1 in human neuroblastoma cells differentiated by retinoic acid: correlation with increased neurite outgrowth response to laminin.

“…Among the matrix components, laminin has an important role as it promotes neurite outgrowth and extension of several nerve cell types (Sanes, 1989). Laminin is produced by Schwann cells and astrocytes (Liesi et al, 1983;Bunge et al, 1989) and is a basal membrane component in the peripheral nerves (Bunge et al, 1989) and in selected regions of the central nervous system (Liesi, 1985). Nerve cells recognize laminin via cell-surface receptors of the integrin family (Reichardt et al, 1989).…”