title: Prospective isolation and characterization of bipotent progenitor cells in early mouse liver development.
abstract: Outgrowth of the foregut endoderm to form the liver bud is considered the initial event of liver development. Hepatic stem/progenitor cells (HSPCs) in the liver bud are postulated to migrate into septum transversum mesenchyme at around embryonic day (E) 9 in mice. The studies of liver development focused on the mid-fetal stage (E11.5-14.5) have identified HSPCs at this stage. However, the in vitro characteristics of HSPCs before E11.5 have not been elucidated. This is probably partly because purification and characterization of HSPCs in early fetal livers have not been fully established. To permit detailed phenotypic analyses of early fetal HSPC candidates, we developed a new coculture system, using mouse embryonic fibroblast cells. In this coculture system, CD13(+)Dlk(+) cells purified from mouse early fetal livers (E9.5 and E10.5) formed colonies composed of both albumin-positive hepatocytic cells and cytokeratin (CK) 19-positive cholangiocytic cells, indicating that early fetal CD13(+)Dlk(+) cells have properties of bipotent progenitor cells. Inhibition of signaling by Rho-associated coiled-coil containing protein kinase (Rock) or by nonmuscle myosin II (downstream from Rock) was necessary for effective expansion of early fetal CD13(+)Dlk(+) cells in vitro. In sorted CD13(+)Dlk(+) cells, expression of the hepatocyte marker genes albumin and α-fetoprotein increased with fetal liver age, whereas expression of CK19 and Sox17, endodermal progenitor cell markers, was highest at E9.5 but decreased dramatically thereafter. These first prospective studies of early fetal HSPC candidates demonstrate that bipotent stem/progenitor cells exist before E11.5 and implicate Rock-myosin II signaling in their development.
authors.affiliation: Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Okada
authors.forename: Akihide
authors.initials: A
authors.lastname: Kamiya
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ito
authors.forename: Ayaka
authors.initials: A
authors.lastname: Yanagida
authors.forename: Hidenori
authors.initials: H
authors.lastname: Ito
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kondou
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishina
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Nakauchi
mesh_terms: D000577:Amides / Q000494:pharmacology; D000818:Animals; D018826:CD13 Antigens / Q000378:metabolism; D002135:Calcium-Binding Proteins; D002450:Cell Communication; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D017077:Culture Media, Conditioned; D004622:Embryo, Mammalian / Q000166:cytology; D053595:Embryonic Stem Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008099:Liver / Q000166:cytology* / Q000196:embryology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D024462:Myosin Type II / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000577:Amides; D002135:Calcium-Binding Proteins; D017077:Culture Media, Conditioned; C512925:Dlk1 protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D047428:Protein Kinase Inhibitors; D011725:Pyridines; C108830:Y 27632; D054460:rho-Associated Kinases; D018826:CD13 Antigens; D024462:Myosin Type II