Chromatin Remodelling in Damaged Intestinal Crypts Orchestrates Redundant TGFβ and Hippo Signalling to Drive Regeneration

Abstract

Cell state dynamics underlying regeneration are under-characterized. Intestinal damage prompts reprogramming into revival stem cells (revSCs) that reconstitute Lgr5+ intestinal stem cells (ISCs). Single nuclei multiomics of chromatin accessibility and transcriptomes during regeneration from irradition showed revSCs display epigenetic profiles shared with ISCs and differentiated lineages. Furthermore, while revSC genes are accessible throughout homeostatic epithelia, damage-induced global alterations in crypt and revSC chromatin converge on TGF{beta}, as well as Hippo pathways. We show TGF{beta} directly induces functional revSCs and demonstrate individual revSCs form organoids with reconstituted Lgr5+ ISCs. Despite this, loss of TGF{beta} signalling yielded mild regenerative defects. In contrast, interference in both Hippo and TGF{beta} abolished revSCs, precluded generation of new ISCs and led to rapid intestinal collapse. Thus, the epithelium is poised to engage the revSC regenerative program that relies on crypt-localized, transient morphogen cues that function in a compensatory manner to support intestinal regeneration.