A model for directed embryonic stem cell differentiation: Establishing lineage-restricted progenitor cell lines

Abstract

The promise of ESC as a panacea for many diseases is based on an unproven expectation that the pluripotency and highly proliferative capacity of ESC lines can be directed to generate sufficient therapeutic cell types. A possible solution is to restrict the differentiation potential of ESC lines to specific cell types without losing their proliferative capacity by establishing lineagerestricted cell lines from ESCs. Here we describe the establishment of clonal, ESC-derived non-pluripotent progenitor cell lines with endothelial potential. Differentiating ESCs from disaggregated embryoid bodies (EBs) were propagated as a monolayer to screen for rare presumptive colonies of progenitor cells with large nucleus to cytoplasm ratio for establishing clonal cell lines. Some of these clonal lines, E-RoSH, resembled the previously described RoSH2 mouse embryonic endothelial progenitor cell lines. Unlike the parental ES cells, E-RoSH cells do not express pluripotent genes, cannot form teratomas in SCID mice and do not express nestin when cultured in suspension. They express high levels of mesodermal genes and differentiate readily to form endothelial cells when plated on matrigel or transplanted into a teratoma.