title: Reversible programming of pluripotent cell differentiation.
abstract: We have undertaken an in vitro differentiation analysis of two related, interconvertible, pluripotent cell populations, ES and early primitive ectoderm-like (EPL) cells, which are most similar in morphology, gene expression, cytokine responsiveness and differentiation potential in vivo to ICM and early primitive ectoderm, respectively. Pluripotent cells were differentiated in vitro as aggregates (embryoid bodies) and the appearance and abundance of cell lineages were assessed by morphology and gene expression. Differentiation in EPL cell embryoid bodies recapitulated normal developmental progression in vivo, but was advanced in comparison to ES cell embryoid bodies, with the rapid establishment of late primitive ectoderm specific gene expression, and subsequent loss of pluripotent cell markers. Nascent mesoderm was formed earlier and more extensively in EPL cell embryoid bodies, and resulted in the appearance of terminally differentiated mesodermal cell types prior to and at higher levels than in ES cell embryoid bodies. Nascent mesoderm in EPL cell embryoid bodies was not specified but could be programmed to alternative fates by the addition of exogenous factors. EPL cells remained competent to form primitive endoderm even though this is not the normal fate of primitive ectoderm in vivo. The establishment of primitive ectoderm-like gene expression and inability to participate in embryogenesis following blastocyst injection is therefore not directly associated with restriction in the ability to form extra-embryonic lineages. However, the EPL cell embryoid body environment did not support differentiation of primitive endoderm to visceral endoderm, indicating the lack of an inductive signal for visceral endoderm formation deduced to originate from the pluripotent cells. Similarly, the inability of EPL cells to form neurons when differentiated as embryoid bodies was attributable to perturbation of the differentiation environment and loss of inductive signals rather than a restricted differentiation potential. Reversion of EPL cells to ES cells was accompanied by restoration of ES cell-like differentiation potential. These results demonstrate the ability of pluripotent cells to adopt developmentally distinct, stable cell states with altered differentiation potentials.
authors.affiliation: Department of Biochemistry, University of Adelaide, Adelaide 5005, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Lake
authors.forename: J
authors.initials: J
authors.lastname: Rathjen
authors.forename: J
authors.initials: J
authors.lastname: Remiszewski
authors.forename: P D
authors.initials: PD
authors.lastname: Rathjen
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology; D019556:COS Cells / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D019070:Cell Lineage; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003470:Culture Media / Q000494:pharmacology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004475:Ectoderm / Q000166:cytology; D004707:Endoderm / Q000166:cytology; D005326:Fetal Proteins / Q000096:biosynthesis / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D006131:Growth Inhibitors / Q000494:pharmacology; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines / Q000494:pharmacology; D008648:Mesoderm / Q000166:cytology; D051379:Mice; D008954:Models, Biological; D009024:Morphogenesis / Q000235:genetics / Q000502:physiology; D009474:Neurons / Q000166:cytology; D009940:Organoids; D013234:Stem Cells / Q000166:cytology*; D014781:Viscera / Q000196:embryology
chemical_list: D003470:Culture Media; D017077:Culture Media, Conditioned; D005326:Fetal Proteins; D006131:Growth Inhibitors; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; C507838:Lif protein, mouse; D008222:Lymphokines