14-P003 Identification of genes expressed in the anterior definitive endoderm

The enteric nervous system (ENS) derives from neural crest, which invade and migrate along the developing gut, proliferate extensively, and differentiate into neurons and glial cells organized as interconnected ganglia that control complex behaviours of the gut, such as peristalsis. While most ENS progenitors undergo differentiation, cells exhibiting properties of enteric progenitor cells (EPCs) can be isolated from embryonic and post-natal mouse gut tissue. Our microarray screen identified that the neural progenitor and stem cell marker SOX2 is expressed in the mouse embryonic ENS. SOX2 is co-expressed with the known EPC marker SOX10. Selecting SOX2 expressing cells provides a possible method for isolating EPCs. Cells derived from embryonic or postnatal gut tissue from a transgenic mouse line in which the bgalneomycin resistance gene fusion protein is knocked into the SOX2 locus (Sox2bgeo) can be cultured under G418 selection, thus allowing substantial enrichment of SOX2 expressing cells. These cells (Sox2bgeoG418) can be propagated in culture for months. Sox2bgeoG418 cells express SOX10 and do not express differentiation markers. Sox2bgeoG418 cells transplanted into the enteric progenitor migratory pathway of mouse and chick embryos migrate along appropriate routes. When transplanted into a mouse gut environment, Sox2bgeoG418 cells migrate, differentiate, and form apparently normal connections with endogenous neurons. Sox2bgeoG418 cells therefore exhibit many properties of enteric progenitors. The ease of maintaining EPCs using this technique lends itself well for use in stem cell replacement studies currently underway in the lab that aim to restore enteric neurons to aganglionic regions in mouse models of Hirschsprung’s disease.