Role of Proto-Oncogene as a Transcriptional Hub to Regulate the Expression of Regeneration-Associated Genes following Preconditioning Peripheral Nerve Injury.

Preconditioning peripheral nerve injury enhances the intrinsic growth capacity of DRGs sensory axons by inducing transcriptional upregulation of the regeneration-associated genes (RAGs). However, it is still unclear how preconditioning injury leads to the orchestrated induction of many RAGs. The present study identified proto-oncogene as a transcriptional hub gene to regulate the expression of a distinct subset of RAGs in DRGs following the preconditioning injury. We demonstrated that c-MYC bound to the promoters of certain RAGs, such as , , and , and that upregulation following SNI preceded that of the RAGs bound by c-MYC. Marked DNA methylation of the exon 3 sequences was implicated in the early transcriptional activation and accompanied by open histone marks. deletion led to a decrease in the injury-induced expression of a distinct subset of RAGs, which were highly overlapped with the list of RAGs that were upregulated by overexpression. Following dorsal hemisection spinal cord injury in female rats, overexpression in DRGs significantly prevented the retraction of the sensory axons in a manner dependent on its downstream RAG, Our results suggest that plays a critical role in axon regeneration via its transcriptional activity to regulate the expression of a spectrum of downstream RAGs and subsequent effector molecules. Identification of more upstream hub transcription factors and the epigenetic mechanisms specific for individual hub transcription factors would advance our understanding of how the preconditioning injury induces orchestrated upregulation of RAGs.