title: Hypoxia represses the differentiation of Rcho-1 rat trophoblast giant cells.
abstract: BACKGROUND
  A hypoxic environment is known to be essential for early placentation. A low oxygen tension induces hypoxia-inducible factor-1 (HIF-1alpha) which may play an important role as a transcription factor in maintaining the proliferative and undifferentiated phenotype in human trophoblasts.
  
  
  METHODS
  We analyzed the effect of a low oxygen tension on the rat trophoblast giant cell differentiation pathway using Rcho-1 cells which were derived from rat choriocarcinomas and consist of trophoblast stem cells.
  
  
  RESULTS
  We found that a low oxygen tension suppressed the morphological changes and steroidogenesis during differentiation. The anticipated downregulation of the Id-1 transcription factor, a negative regulator of trophoblast giant cell differentiation, was not observed in the hypoxic environment. On the other hand, deferoxamine, which mimics hypoxia and induces HIF-1alpha, caused downregulation of Id-1 transcription factor and trophoblast giant cell differentiation.
  
  
  CONCLUSIONS
  These results indicate that hypoxia represses rat trophoblast giant cell differentiation via an HIF-1alpha-independent pathway.
authors.affiliation: Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Osaka, Japan. take@gyne.med.osaka-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Takeda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sakata
authors.forename: Aki
authors.initials: A
authors.lastname: Isobe
authors.forename: Toshiya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Fumihito
authors.initials: F
authors.lastname: Nishimoto
authors.forename: Ryoko
authors.initials: R
authors.lastname: Minekawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Keiichi
authors.initials: K
authors.lastname: Tasaka
authors.forename: Yuji
authors.initials: Y
authors.lastname: Murata
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000037:antagonists & inhibitors; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D000860:Hypoxia; D051793:Hypoxia-Inducible Factor 1 / Q000378:metabolism*; D051381:Rats; D014327:Trophoblasts / Q000502:physiology*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D051793:Hypoxia-Inducible Factor 1