TGFβs modulate permeability of the blood-epididymis barrier in an in vitro model.
The blood-epididymis barrier (BEB) is formed by epithelial tight junctions mediating selective permeability of the epididymal epithelium. Defective barrier function can disturb the balance of the epididymal milieu, which may result in infertility. The stroma of the epididymis contains high amounts of cytokines of the TGFβ family of unknown function. We screened possible effects of all three TGFβ isoforms on paracellular tightness in a BEB in vitro model based on the strongly polarized mouse epididymal epithelial MEPC5 cells in the transwell system. In this model we found a robust transepithelial electrical resistance (TER) of about 840 Ω x cm(2). Effects on the paracellular permeability were evaluated by two methods, TER and FITC-Dextran-based tracer diffusion assays. Both assays add up to corresponding results indicating a time-dependent disturbance of the BEB differentially for the three TGFβ isoforms (TGFβ3>TGFβ1>TGFβ2) in a TGFβ-receptor-1 kinase- and Smad-dependent manner. The tight junction protein claudin-1 was found to be reduced by the treatment with TGFβs, whereas occludin was not influenced. Epididymal epithelial cells are predominantly responsive to TGFβs from the basolateral side, suggesting that TGFβ may have an impact on the epididymal epithelium from the stroma in vivo. Our data show for the first time that TGFβs decrease paracellular tightness in epididymal epithelial cells, thus establishing a novel mechanism of regulation of BEB permeability, which is elementary for sperm maturation and male fertility.
Institute of Anatomy and Cell Biology, Justus-Liebig-University Giessen, Giessen, Germany ; Department of Gynecology and Obstetrics, Justus-Liebig-University Giessen, Giessen, Germany.
Angelika
A
Stammler
Dieter
D
Müller
Yoshiaki
Y
Tabuchi
Lutz
L
Konrad
Ralf
R
Middendorff
D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D062445:Claudin-1 / Q000378:metabolism; D017097:Electric Impedance; D004822:Epididymis / Q000187:drug effects / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008297:Male; D062793:Occludin / Q000378:metabolism; D010539:Permeability / Q000187:drug effects; D021381:Protein Transport; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D062725:Tight Junction Proteins / Q000378:metabolism; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000494:pharmacology
D062445:Claudin-1; D062793:Occludin; D018125:Receptors, Transforming Growth Factor beta; D051900:Smad3 Protein; D062725:Tight Junction Proteins; D016212:Transforming Growth Factor beta