Injury-induced CRMP4 expression in adult sensory neurons; a possible target gene for ciliary neurotrophic factor

▶ Ciliary neurotrophic factor induces CRMP4 in dorsal root ganglion neurons. ▶ Injury induces CRMP4 in dorsal root ganglion neurons. ▶ Injured axons have increased CRMP4 protein in vivo. Neurotrophic cytokines, such as ciliary neurotrophic factor (CNTF) play an important role in the development and regeneration of the nervous system. In the present study, we screened gene expression induced by CNTF in adult dorsal root ganglion (DRG) neurons using the Illumina microarray. We found that the expression of both short and long forms of collapsin response-mediator protein 4 (CRMP4) was increased in cultured primary sensory neurons by CNTF. In addition, sciatic nerve injury induced the expression of CRMP4 mRNA and protein in DRG neurons. Finally, the increased CRMP4 protein was transported into peripheral axons following nerve injury. These findings indicate that CRMP4 may be a target gene for CNTF in the regenerative axon growth of DRG neurons after injury.