title: Investigation of bipotent differentiation of hepatoblasts using inducible diphtheria toxin receptor-transgenic mice.
abstract: OBJECTIVE
  Hepatic progenitor cells, called hepatoblasts, are highly proliferative and exhibit bipotential differentiation into hepatocytes and cholangiocytes in the fetal liver. Thus, they are the ideal source for transplantation therapy. Although several studies have been performed in vitro, the molecular mechanisms regulating hepatoblast differentiation in vivo following transplantation remain poorly understood. The aim of this study was to investigate an in vivo model to analyze hepatoblast bipotency and proliferative ability.
  
  
  METHODS
  Hepatic transplantation model using Cre-inducible diphtheria toxin receptor-transgenic mice (iDTR), and albafpCre mice expressing Cre under the control of albumin and α-fetoprotein (AFP) regulatory elements were established. Fresh hepatoblasts were transplanted into diphtheria toxin (DT)-injected iDTRalbafpCre mice and we analyzed their differentiation and proliferation abilities by immunostaining and gene expression profiles.
  
  
  RESULTS
  Fresh hepatoblasts transplanted into DT-injected iDTRalbafpCre mice engrafted and differentiated into both hepatocytes and cholangiocytes. Additionally, the number of engrafted hepatoblast-derived hepatocytes increased following partial hepatectomy and serial DT injections. Expression levels of hepatic functional genes in transplanted hepatoblast-derived hepatocytes were similar to that of normal hepatocytes.
  
  
  CONCLUSIONS
  In our iDTRalbafpCre transplantation model, fresh hepatoblasts could differentiate into hepatocytes and cholangiocytes. In addition, these donor cells were induced to proliferate by the following liver injury stimulation. This result suggests that this model is valuable for investigating hepatoblast differentiation pathways in vivo.
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.|Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Yanagida
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors.forename: Naoak
authors.initials: N
authors.lastname: Mizuno
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yamazaki
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Kato-Itoh
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Umino
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sato
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.|Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, USA.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ito
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.|Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, USA.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Nakauchi
authors.affiliation: Department of Molecular Life Sciences, Tokai University School of Medicine, Isehara, Japan.
authors.forename: Akihide
authors.initials: A
authors.lastname: Kamiya
keywords: bipotency; diphtheria toxin receptor; hepatoblast; transplantation