title: Epithelial basal cells are distinct from dendritic cells and macrophages in the mouse epididymis.
abstract: The epithelium that lines the epididymal duct establishes the optimal milieu in which spermatozoa mature, acquire motility, and are stored. This finely tuned environment also protects antigenic sperm against pathogens and autoimmunity, which are potential causes of transient or permanent infertility. The epididymal epithelium is pseudostratified and contains basal cells (BCs) that are located beneath other epithelial cells. Previous studies showed that in the mouse epididymis, BCs possess macrophage-like characteristics. However, we previously identified a dense population of cells belonging to the mononuclear phagocyte (MP) system (comprised of macrophages and dendritic cells) in the basal compartment of the mouse epididymis and showed that a subset of MPs express the macrophage marker F4/80. In the present study, we evaluate the distribution of BCs and MPs in the epididymis of transgenic CD11c-EYFP mice, in which EYFP is expressed exclusively in MPs, using antibodies against the BC marker keratin 5 (KRT5) and the macrophage marker F4/80. Immunofluorescence labeling for laminin, a basement membrane marker, showed that BCs and most MPs are located in the basal region of the epithelium. Confocal microscopy showed that in the initial segment, both BCs and MPs project intraepithelial extensions and establish a very intricate network. Flow cytometry experiments demonstrated that epididymal MPs and BCs are phenotypically distinct. BCs do not express F4/80, and MPs do not express KRT5. Therefore, despite their proximity and some morphological similarities with peritubular macrophages and dendritic cells, BCs do not belong to the MP system.
authors.affiliation: Division of Nephrology/Program in Membrane Biology, Massachusetts General Hospital (MGH) and Harvard Medical School, Boston, Massachusetts.
authors.forename: Winnie W
authors.initials: WW
authors.lastname: Shum
authors.forename: Tegan B
authors.initials: TB
authors.lastname: Smith
authors.forename: Virna
authors.initials: V
authors.lastname: Cortez-Retamozo
authors.forename: Lubov S
authors.initials: LS
authors.lastname: Grigoryeva
authors.forename: Jeremy W
authors.initials: JW
authors.lastname: Roy
authors.forename: Eric
authors.initials: E
authors.lastname: Hill
authors.forename: Mikael J
authors.initials: MJ
authors.lastname: Pittet
authors.forename: Sylvie
authors.initials: S
authors.lastname: Breton
authors.forename: Nicolas
authors.initials: N
authors.lastname: Da Silva
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000276:immunology; D018845:CD11 Antigens / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D004822:Epididymis / Q000166:cytology / Q000276:immunology*; D004847:Epithelial Cells / Q000276:immunology; D004848:Epithelium / Q000276:immunology*; D005434:Flow Cytometry; D008264:Macrophages / Q000276:immunology*; D008297:Male; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence
chemical_list: D000943:Antigens, Differentiation; D018845:CD11 Antigens; C036763:monocyte-macrophage differentiation antigen
keywords: basal cells; dendritic cells; epididymis; immunology; macrophages; male reproductive tract; reproductive immunology