title: Maintenance of pluripotency in human and mouse embryonic stem cells through activation of Wnt signaling by a pharmacological GSK-3-specific inhibitor.
abstract: Human and mouse embryonic stem cells (HESCs and MESCs, respectively) self-renew indefinitely while maintaining the ability to generate all three germ-layer derivatives. Despite the importance of ESCs in developmental biology and their potential impact on tissue replacement therapy, the molecular mechanism underlying ESC self-renewal is poorly understood. Here we show that activation of the canonical Wnt pathway is sufficient to maintain self-renewal of both HESCs and MESCs. Although Stat-3 signaling is involved in MESC self-renewal, stimulation of this pathway does not support self-renewal of HESCs. Instead we find that Wnt pathway activation by 6-bromoindirubin-3'-oxime (BIO), a specific pharmacological inhibitor of glycogen synthase kinase-3 (GSK-3), maintains the undifferentiated phenotype in both types of ESCs and sustains expression of the pluripotent state-specific transcription factors Oct-3/4, Rex-1 and Nanog. Wnt signaling is endogenously activated in undifferentiated MESCs and is downregulated upon differentiation. In addition, BIO-mediated Wnt activation is functionally reversible, as withdrawal of the compound leads to normal multidifferentiation programs in both HESCs and MESCs. These results suggest that the use of GSK-3-specific inhibitors such as BIO may have practical applications in regenerative medicine.
authors.affiliation: Laboratory of Molecular Vertebrate Embryology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
authors.forename: Noboru
authors.initials: N
authors.lastname: Sato
authors.forename: Laurent
authors.initials: L
authors.lastname: Meijer
authors.forename: Leandros
authors.initials: L
authors.lastname: Skaltsounis
authors.forename: Paul
authors.initials: P
authors.lastname: Greengard
authors.forename: Ali H
authors.initials: AH
authors.lastname: Brivanlou
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D004622:Embryo, Mammalian / Q000166:cytology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000502:physiology; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors*; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D051379:Mice; D010091:Oximes / Q000494:pharmacology*; D039904:Pluripotent Stem Cells / Q000166:cytology*; D011518:Proto-Oncogene Proteins / Q000187:drug effects* / Q000502:physiology; D051153:Wnt Proteins; D029961:Zebrafish Proteins
chemical_list: C483321:6-bromoindirubin-3'-oxime; D004791:Enzyme Inhibitors; D007211:Indoles; D010091:Oximes; D011518:Proto-Oncogene Proteins; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D038362:Glycogen Synthase Kinase 3