Neurotrophic activity of S-100β in cultures of dorsal root ganglia from embryonic chick and fetal rat

We report here that S-100β, a protein with neurotrophic activity on central nervous system neurons, stimulates neuritic outgrowth from cultures of dorsal root ganglia (DRG). S-100β elicited neurites from explant and dissociated cell cultures of embryonic chick DRG, and the extent of the response varied with the age of the embryo. Specificity was demonstrated by the observation that incubation of S-100β with antibodies directed against S-100β reduced the neurite outgrowth, whereas incubation of S-100β with normal rabbit serum had little effect. S-100β also stimulated the area of neuritic outgrowth from organotypic cultures of fetal rat DRG, showing that the activty of the protein is not restricted to a particular species or culture condition. A mutant S-100β lacking neurotrophic activity on cerebral cortex neurons was unable to effectively stimulate neurite outgrowth from DRG cultures. These studies suggest that S-100β may play a role in neuronal growth and/or maintenance in the peripheral nervous system.