A wound-induced differentiation trajectory for neurons

Abstract

AbstractAnimals capable of whole-body regeneration can replace any missing cell type and regenerate fully-functional new organs,de novo. The regeneration of a new brain requires the formation of diverse neuronal cell types and their assembly into an organized structure and correctly-wired circuits. Recent work in various regenerative animals has revealed transcriptional programs required for the differentiation of distinct neuronal subpopulations, however how these transcriptional programs are initiated upon amputation remains unknown. Here, we focused on the highly regenerative acoel worm,Hofstenia miamia, to study wound-induced transcriptional regulatory events that lead to the production of neurons. Footprinting analysis using chromatin accessibility data on an improved genome assembly revealed that binding sites for the NFY transcription factor complex were significantly bound during regeneration, showing a dynamic increase in binding within one hour upon amputation specifically in tail fragments, which will regenerate a new brain. Strikingly, NFY targets were highly enriched for genes with neuronal functional. Single-cell transcriptome analysis combined with functional studies identifiedsox4+stem cells as the likely progenitor population for multiple neuronal subtypes. Further, we found that wound-inducedsox4expression is likely under direct transcriptional control by NFY, uncovering a mechanism for how early wound-induced binding of a transcriptional regulator results in the initiation of a neuronal differentiation pathway.HighlightsA new chromosome-scale assembly forHofsteniaenables comprehensive analysis of transcription factor binding during regenerationNFY motifs become dynamically bound by 1hpa in regenerating tail fragments, particularly in the loci of neural genesAsox4+neural-specialized stem cell is identified using scRNA-seqsox4is wound-induced and required for differentiation of multiple neural cell typesNFY regulates wound-induced expression ofsox4during regeneration