Sequestration and Synthesis: The Source of Insulin in Cell Clusters Differentiated from Murine Embryonic Stem Cells

The source of insulin released from insulin‐releasing cell clusters (IRCCs) differentiated from embryonic stem cells remains unclear. Rajagopal et al. have suggested that IRCCs do not synthesize but secrete insulin that had been absorbed from media during the multistep protocol. We report here furth...

Full description

Saved in:
Bibliographic Details
Published inStem cells (Dayton, Ohio) Vol. 23; no. 7; pp. 862 - 867
Main Authors Paek, Hyun Joon, Morgan, Jeffrey R., Lysaght, Michael J.
Format Journal Article
LanguageEnglish
Published Bristol John Wiley & Sons, Ltd 01.08.2005
Subjects
Animals
Autoradiography
C-Peptide - chemistry
Cell Differentiation
Cell Proliferation
Cells, Cultured
Culture Techniques
Cysteine - metabolism
Diabetes
Diffusion
Electrophoresis, Polyacrylamide Gel
Embryo, Mammalian - cytology
Embryonic stem cell
Fibroblasts - metabolism
Glucose - metabolism
Glucose stimulation
Guinea Pigs
Immunohistochemistry
Immunoprecipitation
Immunostaining
Insulin
Insulin - metabolism
Insulin Secretion
Islets of Langerhans - cytology
Mice
Microscopy, Electron, Transmission
Peptides - chemistry
Radioisotopes - metabolism
Rats
RNA, Messenger - metabolism
Stem Cells - cytology
Online AccessGet full text

Cover

More Information
Summary:The source of insulin released from insulin‐releasing cell clusters (IRCCs) differentiated from embryonic stem cells remains unclear. Rajagopal et al. have suggested that IRCCs do not synthesize but secrete insulin that had been absorbed from media during the multistep protocol. We report here further data relevant to this controversy. No radioisotopic labeling of insulin was observed when IRCCs were incubated in a medium containing 35S‐cysteine. Less than 1% of the extra‐cellular stoichiometric C‐peptide equivalent to insulin was secreted during glucose stimulation. However, intracellular immunostaining and immunogold labeling were both positive for C‐peptide. Finally, a mass balance calculation showed that simple equilibration of IRCCs by Fickian diffusion from media accounted for at most 4% of secreted insulin. These findings and further analysis of the results of others suggest that the mechanism of insulin secretion by IRCCs is a combination of sequestration and de novo synthesis.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1066-5099
1549-4918
DOI:10.1634/stemcells.2004-0288