title: Identification and expansion of a unique stem cell population from adult mouse gallbladder.
abstract: The identification of resident stem cells in the mouse gallbladder is, to date, unexplored. In addition, the relationship between adult gallbladder stem cells and intrahepatic bile duct (IHBD) cells is not well understood. The aim of this study was to isolate stem cells from an adult mouse gallbladder and determine whether they were unique, compared to IHBD cells. By limiting dilution analyses and index sorts, we found that an EpCAM(+) CD49f(hi) epithelial cell subpopulation from primary gallbladder is enriched in colony-forming cells, compared to EpCAM(+) CD49f(lo) cells. EpCAM(+) CD49f(hi) cells expressed cluster of differentiation (CD)29, CD133, and stem cell antigen-1, but were negative for lineage markers CD31, CD45, and F4/80. Using a novel feeder cell-culture system, we observed long-term (>passage 20) and clonal expansion of the EpCAM(+) CD49f(hi) cells in vitro. In a matrigel differentiation assay, EpCAM(+) CD49f(+) cells expanding in vitro underwent organotypic morphogenesis forming ductular structures and cysts. These structures are similar to, and recapitulate a transport function of, primary gallbladder. EpCAM(+) CD49f(+) cells also engraft into the subcutaneous space of recipient mice. We compared primary gallbladder and IHBD cells by flow cytometry and found phenotypic differences in the expression of CD49f, CD49e, CD81, CD26, CD54, and CD166. In addition, oligonucleotide microarrays showed that the expanded EpCAM(+) CD49f(+) gallbladder cells and IHBD cells exhibit differences related to lipid and drug metabolism. Notable genes that were different are cytochrome P450, glutathione S-transferase, Indian hedgehog, and solute carrier family genes.
  
  
  CONCLUSIONS
  We have isolated an epithelial cell population from primary mouse gallbladder with stem cell characteristics and found it to be unique, compared to IHBD cells.
authors.affiliation: McGowan Institute for Regenerative Medicine, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA.
authors.forename: Rohan
authors.initials: R
authors.lastname: Manohar
authors.forename: Junji
authors.initials: J
authors.lastname: Komori
authors.forename: Lynda
authors.initials: L
authors.lastname: Guzik
authors.forename: Donna B
authors.initials: DB
authors.lastname: Stolz
authors.forename: Uma R
authors.initials: UR
authors.lastname: Chandran
authors.forename: William A
authors.initials: WA
authors.lastname: LaFramboise
authors.forename: Eric
authors.initials: E
authors.lastname: Lagasse
mesh_terms: D053687:Adult Stem Cells / Q000166:cytology* / Q000378:metabolism; D000367:Age Factors; D000818:Animals; D000951:Antigens, Neoplasm / Q000378:metabolism; D001653:Bile Ducts, Intrahepatic / Q000166:cytology; D015415:Biomarkers / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D000071858:Epithelial Cell Adhesion Molecule; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005704:Gallbladder / Q000166:cytology*; D049452:Green Fluorescent Proteins / Q000235:genetics; D039503:Integrin alpha6 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010641:Phenotype; D055153:Stem Cell Niche / Q000502:physiology*
chemical_list: D000951:Antigens, Neoplasm; D015415:Biomarkers; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule; D039503:Integrin alpha6; D049452:Green Fluorescent Proteins