Cells with surface expression of CD133highCD71low are enriched for tripotent colony-forming progenitor cells in the adult murine pancreas

• CD133, expressed by pancreatic ducts of adult mice, enriches colony-forming progenitor cells but at a low efficiency (~ 5%).
• CD71 can be used to sort CD133+ cells into sub-populations, suggesting ductal cells in the adult pancreas are heterogeneous.
• .CD133highCD71low cells are most enriched for colony-forming progenitor cells; their colony-forming efficiency is up to 30%.
• CD133highCD71low cells display stem cell-like behaviors (self-renewal and multi-lineage differentiation in culture).
• CD133highCD71low cells give rise to double-hormonal (Ins+Gcg+) cells that respond to glucose and secrete insulin in vitro.
• Colonies grown from CD133highCD71low cells give rise to single-hormonal, ductal, and acinar cells in diabetic mice.

Progenitor cells in the adult pancreas are potential sources of endocrine beta cells for treating type 1 diabetes. Previously, we identified tri-potent progenitor cells in the adult (2–4 month-old) murine pancreas that were capable of self-renewal and differentiation into duct, acinar, and endocrine cells in vitro. These progenitor cells were named pancreatic colony-forming units (PCFUs). However, because PCFUs are a minor population in the pancreas (~ 1%) they are difficult to study. To enrich PCFUs, strategies using cell-surface marker analyses and fluorescence-activated cell sorting were developed. We found that CD133highCD71low cells, but not other cell populations, enriched PCFUs by up to 30 fold compared to the unsorted cells. CD133highCD71low cells generated primary, secondary, and subsequent colonies when serially re-plated in Matrigel-containing cultures, suggesting self-renewal abilities. In the presence of a laminin hydrogel, CD133highCD71low cells gave rise to colonies that contained duct, acinar, and Insulin+ Glucagon+ double-hormonal endocrine cells. Colonies from the laminin hydrogel culture were implanted into diabetic mice, and five weeks later duct, acinar, and Insulin+ Glucagon− cells were detected in the grafts, demonstrating tri-lineage differentiation potential of CD133highCD71low cells. These CD133highCD71low cells will enable future studies of putative adult pancreas stem cells in vivo.