Adult human pancreatic acinar cells dedifferentiate into an embryonic progenitor-like state in 3D suspension culture.

Human pancreatic exocrine cells were cultured in 3D suspension and formed pancreatospheres composed of acinar-derived and duct-like cells. We investigated, up to 6 days, the fate of human pancreatic acinar cells using fluorescein-conjugated Ulex Europaeus Agglutinin 1 lectin, a previously published acinar-specific non-genetic lineage tracing strategy. At day 4, fluorescence-activated cell sort for the intracellularly incorporated FITC-conjugated UEA1 lectin and the duct-specific CA19.9 surface marker, distinguished acinar-derived cells (UEA1+CA19.9-) from duct-like cells (UEA1-CA19.9+) and acinar-to-duct-like transdifferentiated cells (UEA1+CA19.9+). mRNA expression analysis of the acinar-derived (UEA1+CA19.9-) and duct-like (UEA1-CA19.9+) cell fractions with concomitant immunocytochemical analysis of the pancreatospheres revealed acquisition of an embryonic signature in the UEA1+CA19.9- acinar-derived cells characterized by de novo expression of SOX9 and CD142, robust expression of PDX1 and surface expression of GP2. The colocalisation of CD142, a multipotent pancreatic progenitor surface marker, PDX1, SOX9 and GP2 is reminiscent of a cellular state present during human embryonic development. Addition of TGF-beta signalling inhibitor Alk5iII, induced a 28-fold increased KI67-labeling in pancreatospheres, more pronounced in the CD142+GP2+ acinar-derived cells. These findings with human cells underscore the remarkable plasticity of pancreatic exocrine acinar cells, previously described in rodents, and could find applications in the field of regenerative medicine.