<i>Lgr5</i> + intestinal stem cells are required for organoid survival after genotoxic injury

Progenitors and mature cells can maintain the intestinal epithelium by dedifferentiation and facultative intestinal stem cell (fISC) function when active ISCs (aISCs) are lost to damage. Here, we modeled fISC activation in mouse intestinal organoids with doxorubicin (DXR) treatment, a chemotherapeutic known to ablate Lgr5+ aISCs in vivo. Similar fISC gene activation was observed between organoids treated with low versus high DXR, despite significantly decreased survival at the higher dose. aISCs exhibited dose-dependent loss after DXR treatment but survived at doses compatible with organoid survival. We ablated residual aISCs after DXR treatment using a Lgr52A-DTR allele and observed that aISC survival of the initial genotoxic insult is required for organoid survival following DXR treatment. These results suggest that although typical fISC genes are activated by DXR-induced injury in organoids, functional stemness remains dependent on the aISC pool. Finally, we show that human intestinal organoids require higher doses of DXR to induce loss of survival and downregulation of LGR5. Our data establish a reproducible model of DXR-induced injury in intestinal organoids and reveal differences in in vitro responses to an established in vivo damage modality.