stauprimide priming of human embryonic stem cells toward definitive endoderm

objective: in vitro production of a definitive endoderm (de) is an important issue in stem cell-related differentiation studies and it can assist with the production of more efficient endoderm derivatives for therapeutic applications. despite tremendous progress in de differentiation of human embryonic stem cells (hescs), researchers have yet to discover universal, efficient and cost-effective protocols. materials and methods: in this experimental study, we have treated hescs with 200 nm of stauprimide (spd) for one day followed by activin a (50 ng/ml; a50) for the next three days (spd-a50). in the positive control group, hescs were treated with wnt3a (25 ng/ml) and activin a (100 ng/ml) for the first day followed by activin a for the next three days (100 ng/ml; w/a100-a100). results: gene expression analysis showed up regulation of de-specific marker genes (sox17, foxa2 and cxcr4) comparable to that observed in the positive control group. expression of the other lineage specific markers did not significantly change (p<0.05). we also obtained the same gene expression results using another hesc line. the use of higher concentrations of spd (400 and 800 nm) in the spd-a50 protocol caused an increase in the expression sox17 as well as a dramatic increase in mortality rate of the hescs. a lower concentration of activin a (25 ng/ml) was not able to up regulate the de-specific marker genes. then, a50 was replaced by inducers of definitive endoderm; ide1/2 (ide1 and ide2), two previously reported small molecule (sm) inducers of de, in our protocol (spd-ide1/2). this replacement resulted in the up regulation of visceral endoderm (ve) marker (sox7) but not de-specific markers. therefore, while the spd-a50 protocol led to de production, we have shown that ide1/2 could not fully replace activin a in de induction of hescs. conclusion: these findings can assist with the design of more efficient chemically-defined protocols for de induction of hescs and lead to a better understanding of the different signaling networks that are involved in de differentiation of hescs.