In vivo gene signature of re-epithelialized tissue post-wounding from wildtype or Rnasel KO mice

Mammalian injury responses are characterized by fibrosis and scarring rather than the functional regeneration observed in other phyla. Limited regenerative capacity in mammals could reflect a loss of pro-regeneration programs or active suppression by genes functioning akin to tumor suppressors. To uncover programs governing regeneration in mammals, we investigated Wound Induced Hair Neogenesis (WIHN), a rare example of regeneration in adult mammals1,2. Through comprehensive screening of transcripts associated with both WIHN and human facial rejuvenation after laser treatment, we found the endoribonuclease RNase L to be a powerful suppressor of regeneration. Rnasel-/- mice exhibit remarkable regenerative capacity and accelerated wound healing following injury through the production of IL-36α. Consistent with the known role of RNase L to stimulate caspase-1 signaling, we find that pharmacologic inhibition of caspases promotes regeneration in an IL-36-dependent manner. These responses are not limited to skin but occur following intestinal injury as well, suggesting that suppression of regeneration is a general characteristic of mammalian wound healing. Taken together, this work suggests a therapeutic strategy to uncover latent regenerative capacity and promote functional response to injury. Biopsies of re-epithelialized tissue were recovered from wild-type or Rnasel KO mice approximately 10 days after wounding. Total RNA was extracted and sent for microarray analysis. Deep tissue wounds of 1.25cm^2 were performed on wild-type or Rnasel KO mice. After 10 days the scab detached (SD0), signifying re-epithelialization. SD0 tissue was surgically removed and total RNA was extracted and submitted for microarray analysis. A single KO sample was compared to a single WT sample.