Isolation and characterization of centroacinar/terminal ductal progenitor cells in adult mouse pancreas

Abstract

The question of whether dedicated progenitor cells exist in adult vertebrate pancreas remains controversial. Centroacinar cells and terminal duct (CA/TD) cells lie at the junction between peripheral acinar cells and the adjacent ductal epithelium, and are frequently included among cell types proposed as candidate pancreatic progenitors. However these cells have not previously been isolated in a manner that allows formal assessment of their progenitor capacities. We have found that a subset of adult CA/TD cells are characterized by high levels of ALDH1 enzymatic activity, related to high-level expression of both Aldh1a1 and Aldh1a7. This allows their isolation by FACS using a fluorogenic ALDH1 substrate. FACSisolated CA/TD cells are relatively depleted of transcripts associated with differentiated pancreatic cell types. In contrast, they are markedly enriched for transcripts encoding Sca1, Sdf1, c-Met, Nestin, and Sox9, markers previously associated with progenitor populations in embryonic pancreas and other tissues. FACS-sorted CA/TD cells are uniquely able to form self-renewing "pancreatospheres" in suspension culture, even when plated at clonal density. These spheres display a capacity for spontaneous endocrine and exocrine differentiation, as well as glucose-responsive insulin secretion. In addition, when injected into cultured embryonic dorsal pancreatic buds, these adult cells display a unique capacity to contribute to both the embryonic endocrine and exocrine lineages. Finally, these cells demonstrate dramatic expansion in the setting of chronic epithelial injury. These findings suggest that CA/TD cells are indeed capable of progenitor function and may contribute to the maintenance of tissue homeostasis in adult mouse pancreas.

Detection of an Intermediate Filament Protein in the Pancreas and Mandibular Salivary Gland of the Goat (Capra hircus): An Immunocytochemical Study

“…However, little is known about the presence of some salivary gland cells that could show a progenitor function. Interestingly, it has been reported that the CACs of the pancreas in adult mouse and zebrafish showed a progenitor function and may contribute to the maintenance of tissue homeostasis [31,32]. Similarly, we revealed the presence of centroacinar-like cells in the goat submandibular salivary glands and we hypothesize that cells could have a regenerative role.…”

Pancreas organogenesis: From bud to plexus to gland

“…Isolated ALDH1 þ /Ecadherin þ cells were reported to give rise to all pancreas cell types from small aggregates (''pancreatospheres'') in vitro, and when implanted into cultured pancreatic explants. This observation might provide the strongest support yet for the long-standing proposal that CAC can act as facultative progenitors capable of transdifferentiation (Rovira et al, 2010).…”

“…The CAC could presumably, at a low level, feed progeny towards the normal homeostatic maintenance of the various pancreatic cell types. A study by Rovira et al (2010) detected high relative expression of aldehyde dehydrogenase1 (ALDH1, mainly ALDH1a1 and ALDH1a7) specifically in Ecadherin þ CAC. Isolated ALDH1 þ /Ecadherin þ cells were reported to give rise to all pancreas cell types from small aggregates (''pancreatospheres'') in vitro, and when implanted into cultured pancreatic explants.…”

Postnatal Pancreas of Mice Contains Tripotent Progenitors Capable of Giving Rise to Duct, Acinar, and Endocrine Cells In Vitro

“…These cells can be isolated, expanded, and differentiated in vitro into all three pancreatic lineages, which include glucose-responsive b-like cells [19,20]. The results from these studies and others rationalized the use of in vitro assays not only for the generation of insulin-producing cells for cell replacement therapy, but as a means to identify and characterize pancreatic progenitors particularly from the understudied adult and postnatal stage.…”

“…On the other hand, tri-lineage potential was demonstrated for adult centroacinar cells (enriched by high aldehyde dehydrogenase 1 enzymatic activity) [19] and adult ductal cells (enriched by CD133 and Sox9 co-expression) [20]. These cells can be isolated, expanded, and differentiated in vitro into all three pancreatic lineages, which include glucose-responsive b-like cells [19,20].…”