title: Overexpression of NANOG in human ES cells enables feeder-free growth while inducing primitive ectoderm features.
abstract: Human embryonic stem cells (HESCs) are pluripotent cells derived from the ICM of blastocyst stage embryos. As the factors needed for their growth are largely undefined, they are propagated on feeder cells or with conditioned media from feeder cells. This is in contrast to mouse embryonic stem cells (MESCs) where addition of leukemia inhibitory factor (LIF) replaces the need for a feeder layer. Recently, the transcription factor Nanog was suggested to allow LIF and feeder-free growth of MESCs. Here, we show that NANOG overexpression in HESCs enables their propagation for multiple passages during which the cells remain pluripotent. NANOG overexpressing cells form colonies efficiently even at a very low density, an ability lost upon excision of the transgene. Cells overexpressing NANOG downregulate expression of markers specific to the ICM and acquire expression of a marker specific to the primitive ectoderm (the consecutive pluripotent population in the embryo). Examination of global transcriptional changes upon NANOG overexpression by DNA microarray analysis reveals new markers suggested to discriminate between these populations. These results are significant in the understanding of self-renewal and pluripotency pathways in HESCs, and of their use for modeling early development in humans.
authors.affiliation: Department of Genetics, Institute of Life Sciences, The Hebrew University, Jerusalem, Israel.
authors.forename: Henia
authors.initials: H
authors.lastname: Darr
authors.forename: Yoav
authors.initials: Y
authors.lastname: Mayshar
authors.forename: Nissim
authors.initials: N
authors.lastname: Benvenisty
mesh_terms: D015415:Biomarkers; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D017077:Culture Media, Conditioned; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004475:Ectoderm / Q000166:cytology* / Q000378:metabolism*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D000071317:Nanog Homeobox Protein; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic; D015854:Up-Regulation / Q000235:genetics
chemical_list: D015415:Biomarkers; D017077:Culture Media, Conditioned; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein