RNA-sequencing of injured cultured dorsal root ganglion neurons over time

Injured sensory neurons activate a transcriptional program necessary for robust axon regeneration and eventual target reinnervation. Understanding the transcriptional regulators that govern this axon regenerative response may guide therapeutic strategies to promote axon regeneration in the injured nervous system. Here, we used cultured dorsal root ganglia neurons to identify pro-regenerative transcription factors. Using RNA sequencing, we first characterized this neuronal culture and determined that embryonic day 13.5 DRG (eDRG) neurons cultured for 7 days are similar to e15.5 DRG neurons in vivo and that all neuronal subtypes are represented. This eDRG neuronal culture does not contain other non-neuronal cell types. Next, we performed RNA sequencing at different time points after in vitro axotomy. Analysis of differentially expressed genes revealed upregulation of know regeneration associated transcription factors, including Jun Atf3 and Rest, paralleling the axon injury response in vivo. Analysis of transcription factor binding sites in differentially expressed genes revealed other known transcription factors promoting axon regeneration, such as Myc, Hif1a, Pparg, Ascl1a, Srf, as well as other transcription factors not yet characterized in axon regeneration. We next tested if overexpression of known and novel candidate transcription factors alone or in combination promote axon regeneration in vitro. Our results demonstrate that expression of Ctcf with Yy1 or E2f2 enhances in vitro axon regeneration. Our analysis reveals that pairs of transcription factors can functionally synergize to promote axon regeneration and highlight that transcription factor interaction play an important role as a regulator of axon regeneration. Examine transcriptional changes in DRG neurons after axon injury