title: Isolation and characterization of progenitor cells in uninjured, adult rat lacrimal gland.
abstract: OBJECTIVE
  The purpose of this study was to investigate the presence of progenitor cells in the uninjured, adult rat lacrimal gland (LG).
  
  
  METHODS
  The presence of progenitor cells was examined in LG sections from male rats using antibodies against selected stem cell markers and α-smooth muscle actin (SMA), which marks myoepithelial cells (MECs), by immunofluorescence microscopy (IF). Small, immature cells were isolated after digestion of LG with collagenase and culture in RPMI 1640 for 2 weeks. Immature cells were examined for expression of stem cell markers by IF. Immature cell were grown in neuronal, epithelial, and myoepithelial cell media, and examined by light morphology and IF using antibodies to markers of different cell lineages.
  
  
  RESULTS
  In the intact LGs, MECs expressed the stem cell markers nestin, Musashi 1, ABCG2, Pax6, Chx 10, ΔN p63, and Sox 2. All markers colocalized with SMA. Isolated immature cells contained Ki-67, nestin, Musashi 1, Pax 6, and CHX 10. In neuronal media, immature cells differentiated and assumed a neuronal cell morphology expressing neurofilament 200. In media for human corneal endothelial cells, immature cells differentiated, assumed cobblestone morphology, and labeled with the epithelial marker AE1/AE3. In RPMI media immature cells differentiated into cells with MEC-like morphology, and expressed the MEC markers SMA, α-actinin, adenylate cyclase II, and vimentin.
  
  
  CONCLUSIONS
  We conclude that uninjured, adult LG contains progenitor cells that may be MECs, which can be isolated and differentiated into multiple lineages.
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Marie A
authors.initials: MA
authors.lastname: Shatos
authors.forename: Linda
authors.initials: L
authors.lastname: Haugaard-Kedstrom
authors.forename: Robin R
authors.initials: RR
authors.lastname: Hodges
authors.forename: Darlene A
authors.initials: DA
authors.lastname: Dartt
mesh_terms: D053687:Adult Stem Cells / Q000166:cytology* / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism; D007765:Lacrimal Apparatus / Q000166:cytology* / Q000378:metabolism; D008297:Male; D008856:Microscopy, Fluorescence; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D015415:Biomarkers