title: The cell-surface marker MTS24 identifies a novel population of follicular keratinocytes with characteristics of progenitor cells.
abstract: We describe a novel murine progenitor cell population localised to a previously uncharacterised region between sebaceous glands and the hair follicle bulge, defined by its reactivity to the thymic epithelial progenitor cell marker MTS24. MTS24 labels a membrane-bound antigen present during the early stages of hair follicle development and in adult mice. MTS24 co-localises with expression of alpha6-integrin and keratin 14, indicating that these cells include basal keratinocytes. This novel population does not express the bulge-specific stem cell markers CD34 or keratin 15, and is infrequently BrdU label retaining. MTS24-positive and -negative keratinocyte populations were isolated by flow cytometry and assessed for colony-forming efficiency. MTS24-positive keratinocytes exhibited a two-fold increase in colony formation and colony size compared to MTS24-negative basal keratinocytes. In addition, both the MTS24-positive and CD34-positive subpopulations were capable of producing secondary colonies after serial passage of individual cell clones. Finally, gene expression profiles of MTS24 and CD34 subpopulations were compared. These results showed that the overall gene expression profile of MTS24-positive cells resembles the pattern previously reported in bulge stem cells. Taken together, these data suggest that the cell-surface marker MTS24 identifies a new reservoir of hair follicle keratinocytes with a proliferative capacity and gene expression profile suggestive of progenitor or stem cells.
authors.affiliation: Department of Dermatology, Leiden University Medical Center (LUMC The Netherlands.
authors.forename: Joanne G W
authors.initials: JG
authors.lastname: Nijhof
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Braun
authors.forename: Adam
authors.initials: A
authors.lastname: Giangreco
authors.forename: Carina
authors.initials: C
authors.lastname: van Pelt
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawamoto
authors.forename: Richard L
authors.initials: RL
authors.lastname: Boyd
authors.forename: Rein
authors.initials: R
authors.lastname: Willemze
authors.forename: Leon H F
authors.initials: LH
authors.lastname: Mullenders
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Watt
authors.forename: Frank R
authors.initials: FR
authors.lastname: de Gruijl
authors.forename: Willem
authors.initials: W
authors.lastname: van Ewijk
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D002462:Cell Membrane / Q000502:physiology*; D006197:Hair / Q000502:physiology; D015603:Keratinocytes / Q000166:cytology* / Q000502:physiology; D007633:Keratins / Q000032:analysis; D008562:Membrane Glycoproteins / Q000032:analysis*; D008565:Membrane Proteins / Q000032:analysis*; D051379:Mice; D008812:Mice, Hairless; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology
chemical_list: D018952:Antigens, CD34; D000954:Antigens, Surface; D015415:Biomarkers; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C514060:Mts24 protein, mouse; D007633:Keratins