title: Beta-catenin signaling is required for neural differentiation of embryonic stem cells.
abstract: Culture of embryonic stem (ES) cells at high density inhibits both beta-catenin signaling and neural differentiation. ES cell density does not influence beta-catenin expression, but a greater proportion of beta-catenin is targeted for degradation in high-density cultures. Moreover, in high-density cultures, beta-catenin is preferentially localized to the membrane further reducing beta-catenin signaling. Increasing beta-catenin signaling by treatment with Wnt3a-conditioned medium, by overexpression of beta-catenin, or by overexpression of a dominant-negative form of E-cadherin promotes neurogenesis. Furthermore, beta-catenin signaling is sufficient to induce neurogenesis in high-density cultures even in the absence of retinoic acid (RA), although RA potentiates the effects of beta-catenin. By contrast, RA does not induce neurogenesis in high-density cultures in the absence of beta-catenin signaling. Truncation of the armadillo domain of beta-catenin, but not the C terminus or the N terminus, eliminates its proneural effects. The proneural effects of beta-catenin reflect enhanced lineage commitment rather than proliferation of neural progenitor cells. Neurons induced by beta-catenin overexpression either alone or in association with RA express the caudal neuronal marker Hoxc4. However, RA treatment inhibits the beta-catenin-mediated generation of tyrosine hydroxylase-positive neurons, suggesting that not all of the effects of RA are dependent upon beta-catenin signaling. These observations suggest that beta-catenin signaling promotes neural lineage commitment by ES cells, and that beta-catenin signaling may be a necessary co-factor for RA-mediated neuronal differentiation. Further, enhancement of beta-catenin signaling with RA treatment significantly increases the numbers of neurons generated from ES cells, thus suggesting a method for obtaining large numbers of neural species for possible use in for ES cell transplantation.
authors.affiliation: Department of Neurology, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, IL 60611, USA. j-otero@northwestern.edu
authors.forename: José Javier
authors.initials: JJ
authors.lastname: Otero
authors.forename: Weimin
authors.initials: W
authors.lastname: Fu
authors.forename: Lixin
authors.initials: L
authors.lastname: Kan
authors.forename: Adolfo E
authors.initials: AE
authors.lastname: Cuadra
authors.forename: John A
authors.initials: JA
authors.lastname: Kessler
mesh_terms: D000818:Animals; D015415:Biomarkers; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins; D002454:Cell Differentiation; D002460:Cell Line; D019070:Cell Lineage; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010641:Phenotype; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology; D051153:Wnt Proteins; D051176:beta Catenin; D000099176:Noggin Protein
chemical_list: D015415:Biomarkers; D015820:Cadherins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D014212:Tretinoin; D051153:Wnt Proteins; D051176:beta Catenin; D000099176:Noggin Protein; C495267:CTNNB1 protein, mouse