Isolation of Mouse Pancreatic Ductal Progenitor Cells Expressing CD133 and c-Met by Flow Cytometric Cell Sorting

Background & Aims: Islet transplantation has become available across the globe since a novel protocol was reported. However, because donors are in short supply, only a minority of patients benefit from this procedure. Pancreatic progenitor cells are a promising resource for regeneration of new islets, but whether progenitor cells reside in ductal epithelium is not clear. Methods: Mouse pancreas was examined by immunohistochemistry with cell surface markers specific for ductal cells. We developed an isolation method for ductal cells by flow cytometric cell sorting using a newly identified specific marker for ductal cells. By using an in vitro colony assay, we characterized their proliferative and multipotent capacity. Results: CD133 is expressed specifically in ductal epithelium. Flow cytometric analysis revealed that purified ductal cells are highly enriched in the CD133⁺CD34^-CD45^-Ter119^- fraction. An analysis of clonal epithelial colonies formed by individual cells revealed that progenitor cells with multilineage differentiation capacity are present in neonatal ductal epithelium. Moreover, these progenitor cells express c-Met. In adult mice, progenitor cells that show a high proliferative capacity but appear committed to a ductal lineage are co-purified with CD133⁺CD34^-CD45^-Ter119^- cells. Conclusions: We established a system for isolating and culturing mouse pancreatic ductal cells that relies on flow cytometric cell sorting. Clonal analysis revealed that a population of progenitor cells is present among CD133⁺ ductal cells. Isolation of these cells will facilitate future studies into the roles of pancreatic progenitor cells in regeneration and carcinogenesis.