Long-term in vitro expansion of a human fetal pancreas stem cell that generates all three pancreatic cell lineages.

The mammalian pancreas consists of three epithelial compartments: the acini and ducts of the exocrine pancreas and the endocrine islets of Langerhans. Murine studies indicate that these three compartments derive from a transient, common pancreatic progenitor. Here, we report derivation of 18 human fetal pancreas organoid (hfPO) lines from gestational weeks 8-17 (8-17 GWs) fetal pancreas samples. Four of these lines, derived from 15 to 16 GWs samples, generate acinar-, ductal-, and endocrine-lineage cells while expanding exponentially for >2 years under optimized culture conditions. Single-cell RNA sequencing identifies rare LGR5 cells in fetal pancreas and in hfPOs as the root of the developmental hierarchy. These LGR5 cells share multiple markers with adult gastrointestinal tract stem cells. Organoids derived from single LGR5 organoid-derived cells recapitulate this tripotency in vitro. We describe a human fetal tripotent stem/progenitor cell capable of long-term expansion in vitro and of generating all three pancreatic cell lineages.