Cooperation between HGF and CNTF in promoting the survival and growth of sensory and parasympathetic neurons

Previous studies have shown that hepatocyte growth factor (HGF) enhances the survival and growth of neurons that depend on NGF for survival. To determine if HGF cooperates with other neurotrophic factors in the developing peripheral nervous system, we studied the effect of HGF on parasympathetic ciliary ganglion neurons and proprioceptive trigeminal mesencephalic nucleus (TMN) neurons, both of which survive with CNTF. HGF did not promote the survival of these neurons on its own but did enhance the number that survived with CNTF and increased the length and branching of their neurite arbors. HGF did not, however, enhance the survival and growth of TMN neurons incubated with BDNF, which promoted their survival as effectively as CNTF. These results show that HGF cooperates with CNTF in promoting the survival and growth of parasympathetic and proprioceptive neurons and that within the same neurons, the effects of HGF on survival and growth are selectively dependent on which other signaling pathways are concurrently activated.