GFAP TRANSFECTED CELLS PRODUCE LAMININ, LEADING TO NEURITE OUTGROWTH PROMOTION

ACCUMULATING evidence indicates the importance of astrocytes in neuron al development and regeneration. While glial fibrillary acidic protein (GFAP) is believed to mediate the morphology of developing astrocytes , its precise function remains unknown. To analyse the function of GFA P in astrocytes, we established GFAP-expressing cell lines by transfec tion of mouse GFAP cDNA into mouse fibroblast L cells. Stable transfec tants expressed GFAP uniformly in the cytoplasm with no phenotypic cha nges and exhibited extended processes rich in GFAP. GFAP-expressing ce lls significantly promoted the neurite outgrowth of rat cerebral corte x neurones in the co-culture system. Analysis of the products of GFAP- expressing cells revealed an increase in production of laminin, but no t fibronectin. These results suggest that L cells expressing GFAP incr ease laminin production, leading to promotion of neurite outgrowth.