Growth pattern and NGF-dependent survival of dorsal root ganglia neurons of distinct glyco-phenotype.

Abstract

Cell-surface glyco-phenotypes of dorsal root ganglia (DRG) neurons were specified with monoclonal antibodies (mABs) D1 and E1. D1 demarcated sensory afferents in skin but not muscle target. More than 90% of the drg neurons supported by nerve growth factor (NGF) in vitro were D1 positive (D1+). A fraction of these D1+ neurons, those of small to intermediate soma size, coexpressed a PNGase-sensitive glycoepitope E1, defined by mAB E1. In situ and in vitro, E1+/D1+ and E1-/D1+ neurons and nerve fibers were affiliated. After separation of the two glyco-phenotypes, NGF-dependent survival of E1-/D1+ neurons was no longer observed. Two interrelated concepts emerge from these findings: (a) NGFs survival functions for cutaneous sensory neurons are in part indirect and appear to be based on interneuronal cooperation for survival; and (b) interneuronal survival dependencies are likely to be a decisive factor governing nerve fiber assemblages.