Compared to lentiviral infected controls (undifferentiated) we have concluded that it is within the adherent differentiated cellular aggregates where PDX1and insulincells stay. differentiated in the pancreatic medium were characterized by circulation cytometry (BD fluorescence activated cell sorting), immunostaining and real-time polymerase chain reaction (PCR) (7900HT Fast Realtime PCR System). RESULTS: In the presence of 10% serum MSCs rapidly expand while the epithelial cell populace Quetiapine declines. The percentage of vimentin+ cells increased from 22% 5.83% to 80.43% 3.24% (14 d) and 99.00% 0.0% (21 d), and the percentage of epithelial cells decreased from 74.71% 8.34% to 26.57% 9.75% (14 d) and 4.00% 1.53% (21 d), < 0.01 for all time points. Our novel pancreatic epithelial growth medium preserved the epithelial cell phenotype and minimized epithelial cell dedifferentiation and EMT. Cells expanded in our epithelial medium contained significantly less mesenchymal cells (vimentin+) compared to controls (44.87% 4.93% 95.67% 1.36%; < 0.01). During cell differentiation lentiviral reporting exhibited that, PDX1+ and insulin+ cells were localized within adherent epithelial cell aggregates compared to controls. Compared to starting islets differentiated cells experienced at least two fold higher gene expression of PDX1, insulin, PAX4 and RFX (< 0.05). CONCLUSION: PDX1+ cells were confined to adherent epithelial cell aggregates and not vimentin+ cells (mesenchymal), suggesting that EMT is not a mechanism for generating pancreatic progenitor cells. our previously explained protocol and we confirmed by lineage tracing, circulation cytometry, immunostaining and real-time polymerase Mouse monoclonal antibody to LRRFIP1 chain reaction that islet progenitors reside in the pancreatic epithelium and are not derived via a mesenchymal cell intermediate. INTRODUCTION Islet transplantation is an attractive alternative to daily insulin injections to achieve a more physiological means for restoring glucose homeostasis[1-3]. Identifying and understanding the origin of a potential human -cell progenitor could alleviate the current shortage of donor islets and contribute to the overall knowledge of -cell regeneration. However, the study of -cell progenitors is usually fraught with controversy, as several conflicting models and mechanisms describing the origin and presence of these progenitor cells have been proposed. Despite lineage tracing experiments utilizing transgenic mouse models[4-6] the exact origin of -cell progenitors residing within the pancreas is usually yet to be elucidated. For example -cell progenitors have been proposed to originate from: Quetiapine -cell replication, acinar cell transdifferentiation[7,8], ductal cell transdifferentiation[9-12], pancreas derived multipotent precursors, pluripotent islet survivor cells and -cell dedifferentiation with growth of mesenchymal stem cell (MSC) intermediates epithelial mesenchymal transition (EMT)[15-20]. Previously we reported that MSCs, also referred to as multi-potent stromal cells, could be expanded 12-fold from human islet depleted pancreatic tissue (IDPT) that remains following islet isolation. We exhibited that these pancreatic MSCs could be partially differentiated into islet-like cells. However, in a follow up study we could not restore an epithelial phenotype during tissue culture or generate functional endocrine cells. We hypothesized that this was due in part to our experimental culture conditions, which favored pancreatic MSC growth and negatively selected pancreatic epithelial cells. In this study we statement that, during pancreatic MSC growth, epithelial cells also proliferate and when these epithelial cells are enriched and differentiated, this cell populace expresses developmental transcription factors indicative of a -cell Quetiapine progenitor such as PAX4 and RFX6[24-26]. Therefore, to maintain epithelial cell phenotype and allow long-term study of this cell populace (Ins1) promoter and monomeric reddish fluorescent protein (mRFP) is usually controlled by the mouse promoter we decided that PDX1+ cells observed after 25 d post-differentiation were epithelial cells. Unlike the reversible (EMT) model first explained by Gershengorn et al and the dedifferentiation of -cells then replication of -cell-derived cells explained by Russ et al, we propose that -cell progenitors reside within the human pancreatic epithelium and that these cells have the potential to respond favorably to differentiation without dedifferentiation into a MSC intermediate EMT. Overall, we statement a novel cell culture media that promotes pancreatic epithelial cell survival and minimizes MSC overgrowth, and statement that PDX1+ cells observed 25 d post-differentiation are epithelial cells. MATERIALS AND METHODS Cell growth and differentiation Human islets (= 9) and IDPT (= 13) were obtained from the Edmonton Clinical Islet.
Compared to lentiviral infected controls (undifferentiated) we have concluded that it is within the adherent differentiated cellular aggregates where PDX1and insulincells stay
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