Characterization of growth/differentiation factor 5 (GDF-5) as a neurotrophic factor for cultured neurons from chicken dorsal root ganglia.

Growth/differentiation factor-5 (GDF-5), a morphogenetic protein, has previously been shown to act as a neurotrophic factor for midbrain dopaminergic neurons. To further elucidate the neurotrophic potential of GDF-5, serum free cultures of dorsal root ganglionic (DRG) neurons from developing chick embryos were treated with GDF-5 with or without the simultaneous addition of other trophic factors. Our results show that GDF-5 has a minor promoting effect on its own, but it can enhance the survival promoting effect of neurotrophin-3 (NT-3) and nerve growth factor (NGF) on cultured DRG neurons. Our finding fits well into the concept that neurotrophic factors may act synergistically in ensuring survival of different neuronal populations. The capacity of GDF-5 to reduce the requirement of a subpopulation of sensory neurons for NT-3 may have implications for the treatment of peripheral neuropathies.