Abstract
After injury to the central nervous system (CNS), neuron-intrinsic limitations and extracellular factors in the CNS milieu restrict axon growth potential. A greater understanding of the underlying mechanisms of axon growth may provide therapeutic targets for the development of axon regeneration promoting therapies. Models of enhanced axon growth, such as after a conditioning lesion to the peripheral branch of a dorsal root ganglion or the axon growth observed in the developing CNS compared to a mature CNS, offer opportunities to identify features that differentiate these systems from the adult CNS which lacks regenerative growth potential. We present here a transcriptomic deconvolution of enhanced axon growth driven by selective kinase inhibition in embryonic hippocampal neurons, with the goal of identifying transcriptional regulators associated with potentiated axon growth in embryonic CNS neurons. Through the use of RNA sequencing and transcription factor binding site enrichment analysis we identify transcriptional factors putatively driving differential gene expression during kinase inhibitor-driven enhanced neurite outgrowth. Subsequently, an in vitro phenotypic loss-of-function screen was used to evaluate the list of transcription factor targets for a role in neurite outgrowth. We identified several potential regulators of neurite outgrowth in embryonic hippocampal neurons, and further validation suggested Forkhead box (Fox) family transcription factor Foxp2 restricts neurite outgrowth while FoxO subfamily members Foxo1 and Foxo3a promote neurite outgrowth. Altogether, we designed a combined transcriptomic-phenotypic screening strategy to identify novel transcriptional regulators of neurite outgrowth using transcriptomics-driven biased target selection.