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. mRNA profiles of the murine digit tip at various time points after distal amputation or proximal amputation were generated using high throughput sequencing.