Single-cell transcriptomes of the regenerating intestine reveal a revival stem cell

The turnover of the intestinal epithelium is driven by multipotent LGR5 + crypt-base columnar cells (CBCs) located at the bottom of crypt zones 1 . However, CBCs are lost following injury, such as irradiation 2 , but the intestinal epithelium is nevertheless able to recover 3 . Thus, a second population of quiescent ‘+4’ cells, or reserve stem cells (RSCs), has previously been proposed to regenerate the damaged intestine 4 – 7 . Although CBCs and RSCs were thought to be mutually exclusive 4 , 8 , subsequent studies have found that LGR5 + CBCs express RSC markers 9 and that RSCs were dispensable—whereas LGR5 + cells were essential—for repair of the damaged intestine 3 . In addition, progenitors of absorptive enterocytes 10 , secretory cells 11 – 15 and slow cycling LGR5 + cells 16 have been shown to contribute to regeneration whereas the transcriptional regulator YAP1, which is important for intestinal regeneration, was suggested to induce a pro-survival phenotype in LGR5 + cells 17 . Thus, whether cellular plasticity or distinct cell populations are critical for intestinal regeneration remains unknown. Here we applied single-cell RNA sequencing to profile the regenerating mouse intestine and identified a distinct, damage-induced quiescent cell type that we term the revival stem cell (revSC). revSCs are marked by high clusterin expression and are extremely rare under homoeostatic conditions, yet give rise—in a temporal hierarchy—to all the major cell types of the intestine, including LGR5 + CBCs. After intestinal damage by irradiation, targeted ablation of LGR5 + CBCs, or treatment with dextran sodium sulfate, revSCs undergo a YAP1-dependent transient expansion, reconstitute the LGR5 + CBC compartment and are required to regenerate a functional intestine. These studies thus define a unique stem cell that is mobilized by damage to revive the homoeostatic stem cell compartment and regenerate the intestinal epithelium.