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 th e survival and growth of neurons that depend on NGF for survival. To determ ine if HGF cooperates with other neurotrophic factors in the developing per ipheral nervous system, we studied the effect of HGF on parasympathetic cil iary ganglion neurons and proprioceptive trigeminal mesencephalic nucleus ( TMN) neurons, both of which survive with CNTF. HGF did not promote the surv ival of these neurons on its own but did enhance the number that survived w ith CNTF and increased the length and branching of their neurite arbors. HG F did not, however, enhance the survival and growth of TMN neurons incubate d with BDNF, which promoted their survival as effectively as CNTF. These re sults show that HGF cooperates with CNTF in promoting the survival and grow th of parasympathetic and proprioceptive neurons and that within the same n eurons, the effects of HGF on survival and growth are selectively dependent on which other signaling pathways are concurrently activated.