Nerve-derived Schwann cell precursors, acting in a paracrine fashion, are essential for mammalian digit tip regeneration [MOUSE]. Mus musculus

Multi-tissue regenerative capacity is lost in adult mammals with the exception of the distal digit, which regenerates via largely-uncharacterized mechanisms. Here, we demonstrate that following adult mouse distal digit removal, nerve-associated Schwann cell precursors (N-SCPs) dedifferentiate and secrete growth factors that promote expansion of the blastema and digit regeneration. Specifically, when N-SCPs were dysregulated or ablated, mesenchymal precursor proliferation in the blastema was decreased, nail and bone regeneration were impaired, and regeneration could be rescued by transplantation of exogenous N-SCPs. We show that N-SCPs secreted factors that promoted self-renewal of mesenchymal precursors, and we used transcriptomic and proteomic analysis to define candidate factors. Two of these, oncostatin M (OSM) and PDGF-AA, were made by N-SCPs in the regenerating digit, and rescued the deficits in regeneration caused by loss of N-SCPs due to denervation. Since nerves innervate every peripheral tissue, these results have broad implications for mammalian tissue repair and regeneration. Overall design: We obtained the blastemas from three independent biological replicates of regenerating mouse digits and four independent biological replicates on uninjured mouse digits.