Regulation of Embryonic Chick Insulin Cells: Effect of Retinoic Acid and Insulin-Like Growth Factor 1

Abstract

We are interested in the regulation of early pancreatic differentiation, particularly with regard to factors that enhance insulin cell proliferation. Both retinoic acid and insulin-like growth factor 1 (IGF-1) are known to be important in the proliferation and differentiation of insulin cells. Individually, they have the ability to increase the proportion of insulin cells when added to cultures of chick dorsal pancreatic buds. The aim of this study was to define the action of retinoic acid (RA) in combination with IGF-1 on the proportion of insulin cells. The dorsal pancreatic bud of 5-day-old chick embryos was excised and the endodermal component, with minimal adherent mesenchyme, was explanted onto Matrigel. RA (10^–6 M) and IGF-1 (50 ng/ml) were added to Ham’s F12 culture medium containing transferrin (5 µg/ml) and selenium (10^–10 M) (F12.TS). Control explants were cultured in F12.TS alone or in F12.TS containing dimethyl sulphoxide (DMSO) [F12.TS (DMSO)]. After 7 days in culture, insulin and glucagon cells were localized immunocytochemically; numbers of insulin cells were expressed as a percentage of insulin plus glucagon cell counts. Addition of RA plus IGF-1 to the medium increased the proportion of insulin cells markedly (23.43%) compared with the proportions in control explants (11.3% with F12.TS (DMSO), 13.2% with F12.TS). This increase represents a more than twofold increase in the proportion of insulin cells over that of control explants.

Supplementation of Zinc Induces Retinoic Acid-Mediated Differentiation of Rat Bone Marrow Mesenchymal Stem Cells (Mscs) in to Insulin Producing Cells (Ipcs) in-Vitro

“…The induction was mediated by nicotinamide and retinoic acid as detailed by Kramer. 13,14 These differentiated cells expressed insulin, confirming its potential use as a therapeutic method.…”

Comparison of Ocular Pathologies in Vitamin A–Deficient Mice and RPE65 Gene Knockout Mice

“…It is known that RA may play a critical role in photoreceptor cell morphology regulation. 7 It remains to be determined whether the deprivation of retinol or/and RA in VAD mice is the cause of OS disorganization, which eventually leads to photoreceptor cell degeneration.…”

Retinoic Acid Stimulates the Dynamics of Mouse Gastric Epithelial Progenitors

“…3C, 3D). Insulin could be another factor, because we have recently found it to stimulate proliferation of gastric epithelial progenitors in vitro [30] and retinoic acid has been reported to stimulate insulin production [31]. Finally, because we have observed effects for retinoic acid on epithelial progenitors and two lineages, pit and zymogenic, migrating in different directions and the mRNA and protein expressions of retinoid receptors are localized in more than one cell type in the gastric glands [12, 13], it seems likely that the effects observed in this study due to retinoic acid treatment are via ligand receptor binding.…”