Transcriptomic analysis of bone and fibrous tissue morphogenesis during digit tip regeneration in the adult mouse

Purpose: Investigate the transcriptomic landscape throughout the time course of murine digit regeneration after level-dependent amputation. Methods: The terminal phalanx bone of hind limb digits was subjected to either a distal amputation (25% bone length loss) or proximal amputation (65% bone length loss). Total RNA was isolated from bone and fibrous tissues distal to the distal interphalangeal joint at 12, 14, and 21 days post-amputation (DPA). mRNA library was sequenced using Illumina HiSeq 3000. Trimmed reads were aligned to the mouse genome mm10 and batch-corrected. Results: A limb-specific developmental signaling pathway is transiently upregulated at 14 DPA after distal amputation, corresponding with regeneration of digit tip tissues. Absence of a limb-specific pathway after proximal amputation corresponded with minimal regeneration and fibrotic scarring. Conclusions: Digit regeneration is a level-dependent and spatiotemporally controlled process, with distal and proximal amputations showing significant differences in gene expression and tissue regrowth over time. Overall design: mRNA profiles of the murine digit tip at various time points after distal amputation or proximal amputation were generated using high throughput sequencing.