An acidic pH and activation of phosphoinositide 3-kinase stimulate differentiation of pancreatic progenitors into insulin-producing cells.
Adult pancreatic nonendocrine cells represent a potential alternative source of insulin-producing tissue for the treatment of diabetes. Differentiation of these cells is regulated by various signaling pathways including the phosphoinositide 3-kinase (PI3K) pathway. Therefore, we evaluated the effect of PI3K on this process. Compared with untreated cells the differentiation of human nonendocrine pancreatic cells into insulin-producing elements was increased after treatment with IGF-1, EGF, and Exendin-4, growth factors known to be activators of the PI3K pathway (12.2 +/- 3.2% vs 9.1 +/- 3.2%). Treatment with PI3K pathway inhibitor wortmannin reduced the number of differentiated beta cells from 9.1 +/- 3.2 to 0.7 +/- 0.4%. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed that insulin-like growth factor-1 (IGF-1), epidermal growth factor (EGF), and Exendin-4 significantly increased the expression of the transcription factor neurogenin-3, whereas the expressions of pancreatic and duodenal homeobox 1 (PDX-1), neurogenic differentiation 1 (NeuroD) were increased only among samples treated with ZnCl2 and not significantly affected by treatment with the tested growth factors. Successful differentiation of IGF-1, EGF-, and Exendin-4-treated cells into functional beta cells was confirmed by C-peptide secretion in response to 5 versus 20 mmol glucose stimulation (0.24 vs 0.91 pmol C-peptide/microg DNA). These results showed that activation of the PI3K signaling pathway might be used to stimulate the differentiation of nonendocrine pancreatic cells into insulin-producing elements.
Koblas
T
T
Diabetes Center, Institute for Clinical and Experimental Medicine, Prague, Czech Republic. tokb@ikem.cz
Zacharovova
K
K
Berkova
Z
Z
Girman
P
P
Saudek
F
F
D000328:Adult; D000368:Aged; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D002469:Cell Separation; D017931:DNA Primers; D003973:Diatrizoate / Q000494:pharmacology; D004789:Enzyme Activation; D005362:Ficoll / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry / Q000379:methods; D007328:Insulin / Q000096:biosynthesis* / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology* / Q000378:metabolism; D008875:Middle Aged; D010179:Pancreas / Q000166:cytology* / Q000378:metabolism; D010183:Pancreatic Ducts / Q000166:cytology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism
D017931:DNA Primers; D007328:Insulin; D003973:Diatrizoate; D005362:Ficoll; D019869:Phosphatidylinositol 3-Kinases