Our laboratory has developed a protocol for endoderm differentiation of mouse embryonic stem cells which consists in exposing cells to high concentrations of a nitric oxide donor for 19 hours. This treatment suppresses the expression of pluripotency genes such as Oct4 and Nanog, and induces differentiation events of early acquisition of epithelial morphology and expression of markers of defi nitive endoderm such as Pdx1. We observed in previous studies in mouse embryonic stem cells (mESC) that nitric Oxide causes an increase of the expression of Zic-1, a marker of differentiation toward ectoderm, so we decided to study this gene in endodermic differentiation process. It has been proved that Zic1 and Gli proteins physically and functionally interact through their zinc finger domains, and that Zic1 is essential to the regulation of Sonic Hedgehog (Ssh) pathway in neural development. The aim objective of this study is to determine if Zic1 is regulated by NO, and if this gene has a role in the regulation of Ssh pathway in mESC related with endoderm development. In our early studies in mouse embryonic stem cells (mESCs) we have analysed Zic1 gene and protein expression of cells treated with high concentration of nitric oxide, as well as the DNA methylation on its promoter region, showing that the expression of Zic1 in presence of Nitric Oxide was increased, without significant changes on DNA methylation. Furthermore, we found that the transcription factor Egr1 could active to Zic1 expression after NO treatment. Then we proved that Zic1 coexpressed with Pdx1 in cells treated with NO, in adult pancreatic cells and in pancreas tissue, which are enough evidence to suspect that Zic1 may be involved in the process of differentiation to endoderm. Finally, we determined that NO treatment suppresses Ssh signaling pathway, decreasing the expression of it targets genes. To test whether this modifi cation is promoted by Zic1, we developed gain and loss of function assays of Zic1, reveling thus the possible role of Zic1 in Ssh signaling pathway inhibition and differentiation process toward endoderm in mESC.

Subvencionado por: - Ministerio de Economía y Competitividad-Secretaría de Estado de Investigación Desarrollo e Innovación (IPT-2011-1615-900000) - Junta de Andalucía (CTS- 7127/2011)

Resumen del póster presentado al XXXVII Congreso de la Sociedad Española de Bioquímica y Biología Molecular, celebrado en Granada del 9 al 12 de septiembre de 2014.

Peer reviewed