title: TGF-beta3 regulates the blood-testis barrier dynamics via the p38 mitogen activated protein (MAP) kinase pathway: an in vivo study.
abstract: Recent studies using Sertoli cells cultured in vitro to permit tight junction (TJ) assembly have shown that TJ dynamics are regulated, at least in part, by TGF-beta3 via the p38 mitogen activated protein (MAP) kinase pathway. This in turn regulates the production of occludin, a TJ-integral membrane protein, by Sertoli cells. Yet it is not known if this pathways is used by Sertoli cells to regulate the blood-testis barrier (BTB) function in vivo. Using an in vivo model for studying BTB dynamics, we report herein the CdCl(2)-induced BTB damage in rats was associated with a significant reduction in testicular occludin along with a loss of immunoreactive occludin in the seminiferous epithelium at the site of the BTB. Also, this CdCl(2)-induced occludin loss from the BTB coincided with a surge in testicular TGF-beta3, as well as p-p38 MAP kinase (the phosphorylated/activated form of p38), but not p38 MAP kinase and neither extracellular signal-regulated kinase nor its phosphorylated form (ERK/p-ERK), consistent with results of in vitro studies. More important, intratesticular administration of SB202190, a specific p38 MAP kinase inhibitor, could block the CdCl(2)-induced occludin loss from the BTB. These results illustrate that BTB dynamics in vivo are regulated by the TGF-beta3/p38 MAP kinase pathway, which in turn determines the level of occludin at the site of Sertoli cells TJs.
authors.affiliation: Population Council, New York, New York 10021, USA.
authors.forename: Wing-Yee
authors.initials: WY
authors.lastname: Lui
authors.forename: Ching-Hang
authors.initials: CH
authors.lastname: Wong
authors.forename: Dolores D
authors.initials: DD
authors.lastname: Mruk
authors.forename: C Yan
authors.initials: CY
authors.lastname: Cheng
mesh_terms: D000818:Animals; D019256:Cadmium Chloride / Q000494:pharmacology; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007150:Immunohistochemistry; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D062793:Occludin; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012670:Seminiferous Epithelium / Q000737:chemistry / Q000378:metabolism; D012708:Sertoli Cells / Q000502:physiology; D013737:Testis / Q000098:blood supply* / Q000166:cytology / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D053782:Transforming Growth Factor beta3; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D004791:Enzyme Inhibitors; D007093:Imidazoles; D008565:Membrane Proteins; D062793:Occludin; C568987:Ocln protein, rat; D011725:Pyridines; C509046:Tgfb3 protein, rat; D016212:Transforming Growth Factor beta; D053782:Transforming Growth Factor beta3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D019256:Cadmium Chloride; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole