EFFECTS OF TENASCIN-C IN CULTURED HIPPOCAMPAL ASTROCYTES - NCAM AND FIBRONECTIN IMMUNOREACTIVITY CHANGES

Tenascin-C is an extracellular matrix glycoprotein with trophic and re pulsive properties on neuronal cells, involved in migratory processes of immature neurons. Previous reports demonstrated that this molecule is produced and secreted by astrocytes, in vitro after activation by b FGF or in vivo after CNS lesion. In injured brain the expression of te nascin-C has been correlated with the glial reaction since it was obse rved in regions suffering a dramatic glial proliferation and hypertrop hy. In this report we show that the treatment of cultured hippocampal astrocytes with tenascin-C results in an increased fibronectin and NCA M immunoreactivities. In addition, treated astrocytes form longer exte nsions than control ones. The number of cells as well as the levels of GFAP mRNA and protein immunoreactivity are not modified after tenasci n-C treatment. The present changes may, therefore, be related to the m odification of the adhesive properties of astrocytes to the substrate. These observations are compatible with the hypothesis that tenascin-C may contribute to the glial scarring process. (C) 1997 Wiley-Liss, In c.