Prosaposin-derived peptides enhanced sprouting of sensory neurons in vitroand induced sprouting at motor endplates in vivo

Prosaposin exhibits neurotrophic factor properties that are localized to a 12-amino acid sequence located in the amino terminal portion of the saposin C domain. Prosaptides are peptides derived from the neurotrophic portion o f prosaposin; these have been previously reported to be bioactive in neurob lastoma cell lines in vitro. We report that prosaptides were also bioactive in explants of adult primary sensory neurons by dose-dependently increasin g both the number (3- to 4-fold) and elongation of these neurites by 50%. L ocal injection of prosaptides into the gluteus muscle of adult mice also in duced sprouting at the motor endplate. Our results indicate that prosaptide s are potent neuritogenic factors for both sensory and motor neurons of adu lt peripheral nerve.