GFAP null astrocytes are a favorable substrate for neuronal survival and neurite growth

During the development of the CNS, astrocytes play a key role as a substrat e for neuronal migration and axonal growth. These neuron-astrocyte interact ions could be regulated, in part, by the astrocytic cytoskeleton. Nestin, v imentin, and glial fibrillary acidic protein (GFAF) are the three identifie d proteins constitutive of intermediate filaments present in astrocytes. In the present study, we used mice deficient in GFAP to define the influence of the major protein of the astrocytic cytoskeleton on neuron survival and axonal growth in a model of neuron-astrocyte coculture. We observed that GF AP null astrocytes are a better substrate for neuronal survival and neurite outgrowth than wild-type astrocytes. This may be correlated with the relat ively late occurrence of GFAP expression in astrocyte maturation when the e arly steps of neurogenesis are completed. (C) 2000 Wiley-Liss, Inc.