Proteomic analysis of domestic pig pancreas during development using two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry

Feeder-cell-independent culture of the pig embryonic stem cell-derived exocrine pancreatic cell line, PICM-31

The adaptation to feeder-independent growth of a pig embryonic stem cell-derived pancreatic cell line is described. The parental PICM-31 cell line, previously characterized as an exocrine pancreas cell line, was colony-cloned two times in succession resulting in the derivative cell line, PICM-31A1. PICM-31A1 cells were adapted to growth on a polymerized collagen matrix using feeder cell-conditioned medium and were designated PICM-31FF. Like the parental cells, the PICM-31FF cells were small and grew relatively slowly in closely knit colonies that eventually coalesced into a continuous monolayer. The PICM-31FF cells were extensively cultured: 40 passages at 1:2, 1:3, and finally 1:5 split ratios over a 1-yr period. Ultrastructure analysis showed the cells' epithelial morphology and revealed that they retained their secretory granules typical of pancreas acinar cells. The cells maintained their expression of digestive enzymes, including carboxypeptidase A1 (CPA1), amylase 2A (AMY2A), and phospholipase A2 (PLA2G1B). Alpha-fetoprotein (AFP), a fetal cell marker, continued to be expressed by the cells as was the pancreas alpha cell-associated gene, transthyretin. Several pancreas-associated developmental genes were also expressed by the cells, including pancreatic and duodenal homeobox 1 (PDX1) and pancreas-specific transcription factor, 1a (PTF1A). Proteomic analysis of cellular proteins confirmed the cells' production of digestive enzymes and showed that the cells expressed cytokeratin-8 and cytokeratin-18. The PICM-31FF cell line provides an in vitro model of fetal pig pancreatic exocrine cells without the complicating presence of feeder cells.

Derivation and Characterization of a Pig Embryonic-Stem-Cell-Derived Exocrine Pancreatic Cell Line

OBJECTIVES

The aim of this study was to identify an epithelial cell line isolated from the spontaneous differentiation of totipotent pig epiblast cells.

METHODS

PICM-31 and its colony-cloned derivative cell line, PICM-31A, were established from the culture and differentiation of an epiblast mass isolated from an 8-day-old pig blastocyst. The cell lines were analyzed by transmission electron microscopy, marker gene expression, and mass spectroscopy-based proteomics.

RESULTS

The PICM-31 cell lines were continuously cultured and could be successively colony cloned. They spontaneously self-organized into acinarlike structures. Transmission electron microscopy indicated that the cell lines' cells were epithelial and filled with secretory granules. Candidate gene expression analysis of the cells showed an exocrine pancreatic profile that included digestive enzyme expression, for example, carboxypeptidase A1, and expression of the fetal marker, α-fetoprotein. Pancreatic progenitor marker expression included pancreatic and duodenal homeobox 1, NK6 homeobox 1, and pancreas-specific transcription factor 1a, but not neurogenin 3. Proteomic analysis of cellular proteins confirmed the cells' production of digestive enzymes and showed that the cells expressed cytokeratins 8 and 18.

CONCLUSIONS

The PICM-31 cell lines provide in vitro models of fetal pig pancreatic exocrine cells. They are the first demonstration of continuous cultures, that is, cell lines, of nontransformed pig pancreas cells.

Alpha-1 Antitrypsin as a Therapeutic Agent for Conditions not Associated with Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin is a positive acute phase reactant whose serum level rises in response to inflammatory stress, presumably to balance pro-inflammatory processes. In addition to its serine protease inhibitory action, alpha-1 antitrypsin exhibits broader anti-inflammatory and immunomodulatory activity, and increasing its serum concentration by the administration of exogenous alpha-1 antitrypsin to above-normal levels potentially could be therapeutic in conditions other than alpha-1 antitrypsin deficiency. In vitro observations, studies in animal models and in some instances early human trials suggest that intravenous or inhaled alpha-1 antitrypsin has beneficial effects in type 1 diabetes, viral infections, graft-versus-host disease, cystic fibrosis, and alpha-1 antitrypsin-replete chronic obstructive pulmonary disease among others. While the results of pivotal clinical trials have not been reported to date, new indications for alpha-1 antitrypsin therapy are likely to emerge in the future based on currently available scientific data.