title: Time-sensitive effects of hypoxia on differentiation of neural stem cells derived from mouse embryonic stem cells in vitro.
abstract: OBJECTIVE
  Oxygen tension is an important component of microenvironment for the differentiation of embryonic stem cells including neural lineage. However, the comprehensive influence of hypoxia on neural differentiation during embryonic neural development has not yet been examined.
  
  
  METHODS
  In this study, we investigated the effect of low oxygen levels (5% O(2)), or hypoxia, in two stages of neural differentiation in vitro: (1) inducing mouse embryonic stem cells into neural stem cells (NSCs); and then (2) inducing NSCs into neural progenitor cells in neurospheres.
  
  
  RESULTS
  In the first stage, NSCs generation was reduced under hypoxia. Less mature morphological changes (including neural marker) of NSCs were observed, suggesting the prevention of early differentiation under hypoxic conditions. Thus undifferentiated stem cells were maintained in this stage. However, in the second stage, hypoxia induced neural differentiation in neurospheres. Nevertheless, non-neural progenitor cell formation, such as mesoderm progenitor cell lines or epithelial cell lines, was restricted by low oxygen tension.
  
  
  CONCLUSIONS
  Our results demonstrate that hypoxia is essential for regulating neural differentiation and show the different effects on NSC differentiation dependent on the time-course of NSC development. In the early stage of NSCs induction, hypoxia inhibits neural differentiation and maintains the undifferentiated state; in the later stage of NSCs induction, hypoxia induces neural differentiation. Our study may contribute to the development of new insights for expansion and control of neural differentiation.
authors.forename: Nguyen Huy
authors.initials: NH
authors.lastname: Binh
authors.forename: Hitomi
authors.initials: H
authors.lastname: Aoki
authors.forename: Manabu
authors.initials: M
authors.lastname: Takamatsu
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Hatano
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hirata
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tomita
authors.forename: Akira
authors.initials: A
authors.lastname: Hara
mesh_terms: D000818:Animals; D002452:Cell Count; D015687:Cell Hypoxia / Q000502:physiology*; D002460:Cell Line; D018920:Coculture Techniques; D053595:Embryonic Stem Cells / Q000166:cytology / Q000502:physiology*; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology; D005347:Fibroblasts / Q000502:physiology; D005455:Fluorescent Antibody Technique; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007150:Immunohistochemistry; D008648:Mesoderm / Q000166:cytology / Q000502:physiology; D051379:Mice; D058953:Neural Stem Cells / Q000166:cytology / Q000502:physiology*; D055495:Neurogenesis / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit
keywords: Embryonic stem cells,; Hypoxia,; Neural progenitor cells,; Neural stem cells,; Neuronal development