title: Long-term culture of postnatal mouse hepatic stem/progenitor cells and their relative developmental hierarchy.
abstract: Few studies on the long-term culture of postnatal mouse hepatic stem/progenitor cells have been reported. We successfully adapted a serum-free culture system that we employed previously to expand fetal mouse hepatic stem/progenitor cells and maintained them in culture over long periods. The expanded postnatal cells contained immature alpha-fetoprotein-positive cells along with hepatocytic and cholangiocytic lineage-committed cells. These cells expressed CD49f but not CD45, CD34, Thy-1, c-kit, CD31, or flk-1, and oncostatin M induced their differentiation. This heterogeneous population contained side population (SP) cells, which express the ATP-binding cassette transporter ABCG2, and sca-1+ cells. As mice aged, the frequency of SP and sca-1+ cells decreased along with the ability of cultured cells to expand. Approximately 20%-40% of the SP cells expressed sca-1, but only a few sca-1+ cells were also SP cells. Analysis of colonies derived from single SP or sca-1+ cells revealed that, although both cells had dual differentiation potential and self-renewal ability, SP cells formed colonies more efficiently and gave rise to SP and sca-1+ cells, whereas sca-1+ cells generated only sca-1+ progeny. Thus, SP cells are more characteristic of stem cells than are sca-1+ cells. In regenerating livers, ABCG2+ cells and sca-1+ cells were detected around or in the portal area (the putative hepatic stem cell niche). The expanded cells share many features of fetal hepatic stem/progenitor cells or oval cells and may be useful in determining the mechanisms whereby hepatic stem cells self-renew and differentiate.
authors.affiliation: Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Atsunori
authors.initials: A
authors.lastname: Tsuchiya
authors.forename: Toshio
authors.initials: T
authors.lastname: Heike
authors.forename: Shiro
authors.initials: S
authors.lastname: Baba
authors.forename: Hisanori
authors.initials: H
authors.lastname: Fujino
authors.forename: Katsutsugu
authors.initials: K
authors.lastname: Umeda
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Minoru
authors.initials: M
authors.lastname: Nomoto
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ichida
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Aoyagi
authors.forename: Tatsutoshi
authors.initials: T
authors.lastname: Nakahata
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation; D017931:DNA Primers; D005434:Flow Cytometry; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D008099:Liver / Q000166:cytology* / Q000254:growth & development / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D012313:RNA / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology*
chemical_list: D017931:DNA Primers; D012313:RNA