title: Expression of ion transport-associated proteins in human efferent and epididymal ducts.
abstract: Appropriate intraluminal microenvironment in the epididymis is essential for maturation of sperm. To clarify whether the anion transporters SLC26A2, SLC26A6, SLC26A7, and SLC26A8 might participate in generating this proper intraluminal milieu, we studied the localization of these proteins in the human efferent and the epididymal ducts by immunohistochemistry. In addition, immunohistochemistry of several SLC26-interacting proteins was performed: the Na(+)/H(+) exchanger 3 (NHE3), the Cl(-) channel cystic fibrosis transmembrane conductance regulator (CFTR), the proton pump V-ATPase, their regulator Na(+)/H(+) exchanger regulating factor 1 (NHERF-1), and carbonic anhydrase II (CAII). Our results show that SLC26A6, CFTR, NHE3, and NHERF-1 are co-expressed on the apical side of the nonciliated cells, and SLC26A2 appears in the cilia of the ciliated cells in the human efferent ducts. In the epididymal ducts, SLC26A6, CFTR, NHERF-1, CAII, and V-ATPase (B and E subunits) were co-localized to the apical mitochondria rich cells, while SLC26A7 was expressed in a subgroup of basal cells. SLC26A8 was not found in the structures studied. This is the first study describing the localization of SLC26A2, A6 and A7, and NHERF-1 in the efferent and the epididymal ducts. Immunolocalization of human CFTR, NHE3, CAII, and V-ATPase in these structures differs partly from previous reports from rodents. Our findings suggest roles for these proteins in male fertility, either independently or through interaction and reciprocal regulation with co-localized proteins shown to affect fertility, when disrupted.
authors.affiliation: Department of Medical Genetics, University of Helsinki, Helsinki, Finland. minna.kujala@helsinki.fi
authors.forename: Minna
authors.initials: M
authors.lastname: Kujala
authors.forename: Satu
authors.initials: S
authors.lastname: Hihnala
authors.forename: Jukka
authors.initials: J
authors.lastname: Tienari
authors.forename: Kari
authors.initials: K
authors.lastname: Kaunisto
authors.forename: Johanna
authors.initials: J
authors.lastname: Hästbacka
authors.forename: Christer
authors.initials: C
authors.lastname: Holmberg
authors.forename: Juha
authors.initials: J
authors.lastname: Kere
authors.forename: Pia
authors.initials: P
authors.lastname: Höglund
mesh_terms: D000328:Adult; D000368:Aged; D027321:Anion Transport Proteins / Q000032:analysis; D017920:Antiporters / Q000032:analysis; D024402:Carbonic Anhydrase II / Q000032:analysis; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000032:analysis; D004822:Epididymis / Q000737:chemistry*; D006801:Humans; D007150:Immunohistochemistry; D017136:Ion Transport / Q000502:physiology*; D008297:Male; D026901:Membrane Transport Proteins / Q000032:analysis*; D008875:Middle Aged; D010750:Phosphoproteins / Q000032:analysis; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000032:analysis; D000076988:Sulfate Transporters; D016707:Tissue Fixation; D025262:Vacuolar Proton-Translocating ATPases / Q000032:analysis; D014649:Vas Deferens / Q000737:chemistry*
chemical_list: D027321:Anion Transport Proteins; D017920:Antiporters; D026901:Membrane Transport Proteins; D010750:Phosphoproteins; C089651:SLC26A2 protein, human; C439529:SLC26A6 protein, human; C455626:SLC26A7 protein, human; C455627:SLC26A8 protein, human; C000613385:SLC9A3 protein, human; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; D000076988:Sulfate Transporters; C093376:sodium-hydrogen exchanger regulatory factor; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D025262:Vacuolar Proton-Translocating ATPases; D024402:Carbonic Anhydrase II