title: Two populations of Thy1-positive mesenchymal cells regulate in vitro maturation of hepatic progenitor cells.
abstract: We previously reported that the in vitro maturation of CD49f(+)Thy1(-)CD45(-) (CD49f positive) fetal hepatic progenitor cells (HPCs) is supported by Thy1-positive mesenchymal cells derived from the fetal liver. These mesenchymal cell preparations contain two populations, one of a cuboidal shape and the other spindle shaped in morphology. In this study, we determined that the mucin-type transmembrane glycoprotein gp38 could distinguish cuboidal cells from spindle cells by immunocytochemistry. RT-PCR analysis revealed differences between isolated CD49f(+/-)Thy1(+)gp38(+)CD45(-) (gp38 positive) cells and CD49f(+/-)Thy1(+)gp38(-)CD45(-) (gp38 negative) cells, whereas both cells expressed mesenchymal cell markers. The coculture with gp38-positive cells promoted the maturation of CD49f-positive HPCs, which was estimated by positivity for periodic acid-Schiff (PAS) staining, whereas the coculture with gp38-negative cells maintained CD49f-positive HPCs negative for PAS staining. The expression of mature hepatocyte markers, such as tyrosine aminotransferase, tryptophan-2,3-dioxygenase, and glucose-6-phosphatase, were upregulated on HPCs by coculture with gp38-positive cells. Furthermore, transmission electron microscopy revealed the acquisition of mature hepatocyte features by HPCs cocultured with gp38-positive cells. This effect on maturation of HPCs was inhibited by the addition of conditioned medium derived from gp38-negative cells. By contrast, the upregulation of bromodeoxyuridine incorporation by HPCs demonstrated the proliferative effect of coculture with gp38-negative cells. In conclusion, these results suggest that in vitro maturation of HPCs promoted by gp38-positive cells may be opposed by an inhibitory effect of gp38-negative cells, which likely maintain the immature, proliferative state of HPCs.
authors.affiliation: Dept of Surgery, Graduate School of Medicine, Kyoto Univ, Shogoin, Kyoto, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Kamo
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yasuchika
authors.forename: Hideaki
authors.initials: H
authors.lastname: Fujii
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Hoppo
authors.forename: Takafumi
authors.initials: T
authors.lastname: Machimoto
authors.forename: Takamichi
authors.initials: T
authors.lastname: Ishii
authors.forename: Naoya
authors.initials: N
authors.lastname: Fujita
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuruo
authors.forename: Jun K
authors.initials: JK
authors.lastname: Yamashita
authors.forename: Hajime
authors.initials: H
authors.lastname: Kubo
authors.forename: Iwao
authors.initials: I
authors.lastname: Ikai
mesh_terms: D000199:Actins / Q000032:analysis / Q000235:genetics; D000818:Animals; D018952:Antigens, CD34 / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D049109:Cell Proliferation; D002469:Cell Separation; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D003893:Desmin / Q000032:analysis / Q000235:genetics; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D039503:Integrin alpha6 / Q000032:analysis / Q000235:genetics; D016023:Integrins / Q000235:genetics; D008099:Liver / Q000166:cytology* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000032:analysis; D008648:Mesoderm / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D018800:Thy-1 Antigens / Q000032:analysis*; D014366:Tryptophan Oxygenase / Q000235:genetics; D014444:Tyrosine Transaminase / Q000235:genetics; D014746:Vimentin / Q000235:genetics; D000098853:Podoplanin
chemical_list: D000199:Actins; D018952:Antigens, CD34; D017077:Culture Media, Conditioned; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D003893:Desmin; D039503:Integrin alpha6; D016023:Integrins; D008562:Membrane Glycoproteins; D018800:Thy-1 Antigens; D014366:Tryptophan Oxygenase; D014444:Tyrosine Transaminase; D014746:Vimentin; C490441:Pdpn protein, mouse; D000098853:Podoplanin