title: The double inhibition of endogenously produced BMP and Wnt factors synergistically triggers dorsal telencephalic differentiation of mouse ES cells.
abstract: Embryonic stem (ES) cells are becoming a popular model of in vitro neurogenesis, as they display intrinsic capability to generate neural progenitors that undergo the known steps of in vivo neural development. These include the acquisition of distinct regional fates, which depend on growth factors and signals that are present in the culture medium. The control of the intracellular signaling that is active at different steps of ES cell neuralization, even when cells are cultured in chemically defined medium, is complicated by the endogenous production of growth factors. However, this endogenous production has been poorly investigated so far. To address this point, we performed a high-throughput analysis of the expression of morphogens during mouse ES cell neuralization in minimal medium. We found that during their neuralization, ES cells increased the expression of members of Wnt, Fibroblast Growth Factor (FGF), and BMP families. Conversely, the expression of Activin/Nodal and Shh ligands was low in early steps of neuralization. In this experimental condition, neural progenitors and neurons generated by ES cells expressed a gene expression profile that was consistent with a midbrain identity. We found that endogenous BMP and Wnt signaling, but not FGF signaling, synergistically affected ES cell neural patterning, by turning off a profile of dorsal/telencephalic gene expression. Double BMP and Wnt inhibition allowed neuralized ES cells to sequentially activate key genes of cortical differentiation. Our findings are consistent with a novel synergistic effect of Wnt and BMP endogenous signaling of ES cells in inhibiting a cortical differentiation program.
authors.affiliation: Scuola Normale Superiore, Classe di Scienze, Pisa, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Bertacchi
authors.forename: Luca
authors.initials: L
authors.lastname: Pandolfini
authors.forename: Mara
authors.initials: M
authors.lastname: D'Onofrio
authors.forename: Rossella
authors.initials: R
authors.lastname: Brandi
authors.forename: Federico
authors.initials: F
authors.lastname: Cremisi
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002540:Cerebral Cortex / Q000166:cytology*; D053595:Embryonic Stem Cells / Q000166:cytology*; D005346:Fibroblast Growth Factors / Q000037:antagonists & inhibitors / Q000378:metabolism; D015870:Gene Expression / Q000502:physiology*; D051379:Mice; D015398:Signal Transduction / Q000502:physiology*; D051153:Wnt Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D019485:Bone Morphogenetic Proteins; D051153:Wnt Proteins; D005346:Fibroblast Growth Factors
keywords: BMP; Wnt; cortical fate; in vitro neurogenesis; mouse embryonic stem cells