title: Gonadotropin suppression in men leads to a reduction in claudin-11 at the Sertoli cell tight junction.
abstract: OBJECTIVE
  Are Sertoli cell tight junctions (TJs) disrupted in men undergoing hormonal contraception?
  
  
  CONCLUSIONS
  Localization of the key Sertoli cell TJ protein, claudin-11, was markedly disrupted by 8 weeks of gonadotropin suppression, the degree of which was related to the extent of adluminal germ cell suppression.
  
  
  BACKGROUND
  Sertoli cell TJs are vital components of the blood-testis barrier (BTB) that sequester developing adluminal meiotic germ cells and spermatids from the vascular compartment. Claudin-11 knockout mice are infertile; additionally claudin-11 is spatially disrupted in chronically gonadotropin-suppressed rats coincident with a loss of BTB function, and claudin-11 is disorganized in various human testicular disorders. These data support the Sertoli cell TJ as a potential site of hormonal contraceptive action.
  
  
  METHODS
  BTB proteins were assessed by immunohistochemistry (n = 16 samples) and mRNA (n = 18 samples) expression levels in available archived testis tissue from a previous study of 22 men who had undergone 8 weeks of gonadotropin suppression and for whom meiotic and post-meiotic germ cell numbers were available. The gonadotropin suppression regimens were (i) testosterone enanthate (TE) plus the GnRH antagonist, acyline (A); (ii) TE + the progestin, levonorgestrel, (LNG); (iii) TE + LNG + A or (iv) TE + LNG + the 5α-reductase inhibitor, dutasteride (D). A control group consisted of seven additional men, with three archived samples available for this study.
  
  
  METHODS
  Immunohistochemical localization of claudin-11 (TJ) and other junctional type markers [ZO-1 (cytoplasmic plaque), β-catenin (adherens junction), connexin-43 (gap junction), vinculin (ectoplasmic specialization) and β-actin (cytoskeleton)] and quantitative PCR was conducted using matched frozen testis tissue.
  
  
  RESULTS
  Claudin-11 formed a continuous staining pattern at the BTB in control men. Regardless of gonadotropin suppression treatment, claudin-11 localization was markedly disrupted and was broadly associated with the extent of meiotic/post-meiotic germ cell suppression; claudin-11 staining was (i) punctate (i.e. 'spotty' appearance) at the basal aspect of tubules when the average numbers of adluminal germ cells were <15% of control, (ii) presented as short fragments with cytoplasmic extensions when numbers were 15-25% of control or (iii) remained continuous when numbers were >40% of control. Changes in localization of connexin-43 and vinculin were also observed (smaller effects than for claudin-11) but ZO-1, β-catenin and β-actin did not differ, compared with control.
  
  
  CONCLUSIONS
  Claudin-11 was the only Sertoli cell TJ protein investigated, but it is considered to be the most pivotal of constituent proteins given its known implication in infertility and BTB function. We were limited to testis samples which had been gonadotropin-suppressed for 8 weeks, shorter than the 74-day spermatogenic wave, which may account for the heterogeneity in claudin-11 and germ cell response observed among the men. Longer suppression (12-24 weeks) is known to suppress germ cells further and claudin-11 disruption may be more uniform, although we could not access such samples.
  
  
  CONCLUSIONS
  These findings are important for our understanding of the sites of action of male hormonal contraception, because they suggest that BTB function could be ablated following long-term hormone suppression treatment.
  
  
  BACKGROUND
  National Health and Medical Research Council (Australia) Program Grants 241000 and 494802; Research Fellowship 1022327 (to R.I.M.) and the Victorian Government's Operational Infrastructure Support Program. None of the authors have any conflicts to disclose.
  
  
  BACKGROUND
  Not applicable.
authors.affiliation: Hudson Institute of Medical Research, Monash Medical Centre, Clayton, VIC 3168, Australia Department of Molecular and Translational Science, Monash University, Clayton, VIC 3168, Australia Applied Biology/Biotechnology, Royal Melbourne Institute of Technology University, Bundoora, VIC 3088, Australia Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia St Vincent's Clinical School, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: M J
authors.initials: MJ
authors.lastname: McCabe
authors.affiliation: Hudson Institute of Medical Research, Monash Medical Centre, Clayton, VIC 3168, Australia Department of Molecular and Translational Science, Monash University, Clayton, VIC 3168, Australia Dame Roma Mitchell Cancer Research Laboratories, Discipline of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
authors.forename: G A
authors.initials: GA
authors.lastname: Tarulli
authors.affiliation: Dame Roma Mitchell Cancer Research Laboratories, Discipline of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
authors.forename: G
authors.initials: G
authors.lastname: Laven-Law
authors.affiliation: Hudson Institute of Medical Research, Monash Medical Centre, Clayton, VIC 3168, Australia Department of Molecular and Translational Science, Monash University, Clayton, VIC 3168, Australia.
authors.forename: K L
authors.initials: KL
authors.lastname: Matthiesson
authors.affiliation: Hudson Institute of Medical Research, Monash Medical Centre, Clayton, VIC 3168, Australia Department of Molecular and Translational Science, Monash University, Clayton, VIC 3168, Australia Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3168, Australia.
authors.forename: S J
authors.initials: SJ
authors.lastname: Meachem
authors.affiliation: Hudson Institute of Medical Research, Monash Medical Centre, Clayton, VIC 3168, Australia Department of Molecular and Translational Science, Monash University, Clayton, VIC 3168, Australia.
authors.forename: R I
authors.initials: RI
authors.lastname: McLachlan
authors.affiliation: Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia St Vincent's Clinical School, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: M E
authors.initials: ME
authors.lastname: Dinger
authors.affiliation: Hudson Institute of Medical Research, Monash Medical Centre, Clayton, VIC 3168, Australia Department of Molecular and Translational Science, Monash University, Clayton, VIC 3168, Australia peter.stanton@hudson.org.au.
authors.forename: P G
authors.initials: PG
authors.lastname: Stanton
mesh_terms: D058891:5-alpha Reductase Inhibitors / Q000494:pharmacology; D000328:Adult; D000728:Androgens / Q000494:pharmacology; D001814:Blood-Testis Barrier / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D057167:Claudins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D003272:Contraceptive Agents, Male / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects*; D000068538:Dutasteride / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D006801:Humans; D007150:Immunohistochemistry; D016912:Levonorgestrel / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D015203:Reproducibility of Results; D012708:Sertoli Cells / Q000166:cytology / Q000187:drug effects*; D013091:Spermatogenesis / Q000187:drug effects; D013739:Testosterone / Q000031:analogs & derivatives / Q000494:pharmacology; D019108:Tight Junctions / Q000187:drug effects*; D055815:Young Adult
chemical_list: D058891:5-alpha Reductase Inhibitors; D000728:Androgens; C120453:CLDN11 protein, human; D057167:Claudins; D003272:Contraceptive Agents, Male; D009842:Oligopeptides; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D016912:Levonorgestrel; C004648:testosterone enanthate; D000068538:Dutasteride; C109238:acyline
keywords: Male hormonal contraception; Sertoli cell tight junction; claudin-11; human; spermatogenesis