620 RNase L is a regeneration repressor gene

Abstract

Mammalian injury responses are characterized by fibrosis and scarring rather than functional regeneration. 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 performed comprehensive transcript screening in human subjects after laser rejuvenation treatment and cross-referenced these transcripts to those found in mice with enhanced Wound Induced Hair Neogenesis (WIHN), a rare example of mammalian organogenesis. We find the anti-viral endoribonuclease RNase L to be a powerful suppressor of regeneration. Rnasel-/- mice exhibit remarkable regenerative capacity, with elevated WIHN (n=10, p<0.0001) through enhanced IL-36α (n=3, p<0.01). Consistent with the known role of RNase L to stimulate caspase-1, we find that pharmacologic inhibition of caspases promotes regeneration (n=3 versus 4, p<0.001) in a novel IL-36-dependent manner (n=4, n.s.= not significant). Additionally, these responses are not limited to skin but extend to other organs, such as the colon (n=4, p<0.05), suggesting that suppression of regeneration is a fundamental characteristic of epithelial wound healing. Taken together, this work suggests that RNaseL functions as a regeneration repressor gene in a functional tradeoff that prioritizes host antiviral abilities and is a target to enhance healing in multiple epithelial organs, perhaps even during viral infection.