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Peter G Stanton - One of the best experts on this subject based on the ideXlab platform.
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Gonadotropin suppression in men leads to a reduction in Claudin-11 at the Sertoli cell tight junction
Human Reproduction, 2016Co-Authors: Mark J. Mccabe, Sarah J Meachem, Robert I Mclachlan, Gerard A. Tarulli, Geraldine Laven-law, K.l. Matthiesson, Marcel E. Dinger, Peter G StantonAbstract:STUDY QUESTION: Are Sertoli cell tight junctions (TJs) disrupted in men undergoing hormonal contraception? SUMMARY ANSWER: 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. WHAT IS KNOWN ALREADY: 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. STUDY DESIGN SIZE DURATION: 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 5alpha-reductase inhibitor dutasteride (D). A control group consisted of seven additional men with three archived samples available for this study. PARTICIPANTS/MATERIALS SETTINGS METHODS: Immunohistochemical localization of Claudin-11 (TJ) and other junctional type markers [ZO-1 (cytoplasmic plaque) beta-catenin (adherens junction) connexin-43 (gap junction) vinculin (ectoplasmic specialization) and beta-actin (cytoskeleton)] and quantitative PCR was conducted using matched frozen testis tissue. MAIN RESULTS AND THE ROLE OF CHANCE: 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 40% of control. Changes in localization of connexin-43 and vinculin were also observed (smaller effects than for Claudin-11) but ZO-1 beta-catenin and beta-actin did not differ compared with control. LIMITATIONS REASONS FOR CAUTION: 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. WIDER IMPLICATIONS OF THE FINDINGS: 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. STUDY FUNDING/COMPETING INTERESTS: National Health and Medical Research Council (Australia) Program Grants 241000 and 494802; Research Fellowship 1022327 (to R.I.M.) and the Victorian Governments Operational Infrastructure Support Program. None of the authors have any conflicts to disclose. TRIAL REGISTRATION NUMBER: Not applicable. (c) The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions please email: journals.permissions@oup.com.
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Claudin-11 and occludin are major contributors to Sertoli cell tight junction function, in vitro
Asian Journal of Andrology, 2016Co-Authors: Mark J. Mccabe, Caroline F.h. Foo, Marcel E. Dinger, Peter M. Smooker, Peter G StantonAbstract:The Sertoli cell tight junction (TJ) is the key component of the blood-testis barrier, where it sequesters developing germ cells undergoing spermatogenesis within the seminiferous tubules. Hormonally regulated Claudin-11 is a critical transmembrane protein involved in barrier function and its murine knockout results in infertility. We aimed to assess quantitatively the significance of the contribution of Claudin-11 to TJ function, in vitro, using siRNA-mediated gene silencing. We also conducted an analysis of the contribution of occludin, another intrinsic transmembrane protein of the TJ. Silencing of Claudin-11 and/or occludin was conducted using siRNA in an immature rat Sertoli cell culture model. Transepithelial electrical resistance was used to assess quantitatively TJ function throughout the culture. Two days after siRNA treatment, cells were fixed for immunocytochemical localization of junction proteins or lyzed for RT-PCR assessment of mRNA expression. Silencing of Claudin-11, occludin, or both resulted in significant decreases in TJ function of 55% (P < 0.01), 51% (P < 0.01), and 62% (P < 0.01), respectively. Data were concomitant with significant decreases in mRNA expression and marked reductions in the localization of targeted proteins to the Sertoli cell TJ. We provide quantitative evidence that Claudin-11 contributes significantly (P < 0.01) to Sertoli cell TJ function in vitro. Interestingly, occludin, which is hormonally regulated but not implicated in infertility until late adulthood, is also a significant (P < 0.01) contributor to barrier function. Our data are consistent with in vivo studies that clearly demonstrate a role for these proteins in maintaining normal TJ barrier structure and function.
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Claudin 11 and connexin 43 display altered spatial patterns of organization in men with primary seminiferous tubule failure compared with controls
Fertility and Sterility, 2013Co-Authors: Jenna T Haverfield, Sarah J Meachem, Moira K Obryan, Peter G Stanton, Robert I MclachlanAbstract:Objective To assess the spatial organization of two proteins involved in the Sertoli cell junctional complex in men with primary seminiferous tubule failure. Design Retrospective study. Setting Medical research institute. Patient(s) Sixteen men total, six with meiotic arrest, seven with the Sertoli cell-only phenotype, and three with normal spermatogenesis. Intervention(s) None. Main Outcome Measure(s) Differences in Claudin-11 and connexin-43 organization as detected using confocal microscopy. Result(s) In men with primary seminiferous tubule failure, four organizational patterns (I–IV) were recognized and quantified for Claudin-11. Across these patterns, Claudin-11 changed from a basal filamentous staining pattern to a punctate staining pattern with diffuse localization throughout the entire epithelium. Similar changes in staining patterns for connexin-43 were observed. Major differences were seen in the spatial organization of Claudin-11 and connexin-43 in tubules from control men compared with tubules with primary seminiferous tubule failure, but we observed no differences in the spatial organization of these proteins in tubules from men with meiotic arrest and Sertoli cell-only phenotypes. Conclusion(s) The spatial organization of Claudin-11 and connexin-43 is altered in men with primary seminiferous tubule failure. Disorganization of the proteins composing the Sertoli cell junctional complex may be involved in the spermatogenic impairment, possibly via loss of blood-testis barrier function.
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androgen initiates sertoli cell tight junction formation in the hypogonadal hpg mouse
Biology of Reproduction, 2012Co-Authors: Peter G Stanton, Mark J. Mccabe, Charles M Allan, Peter K Nicholls, Kirsten J MctavishAbstract:Sertoli cell tight junctions (TJs) form at puberty as a major component of the blood-testis barrier (BTB), which is essential for spermatogenesis. This study characterized the hormonal induction of functional Sertoli cell TJ formation in vivo using the gonadotropin-deficient hypogonadal (hpg) mouse that displays prepubertal spermatogenic arrest. Androgen actions were determined in hpg mice treated for 2 or 10 days with dihydrotestosterone (DHT). Follicle-stimulating hormone (FSH) actions were studied in hpg mice expressing transgenic human FSH (hpg+tgFSH) with or without DHT treatment. TJ formation was examined by mRNA expression and immunolocalization of TJ proteins Claudin-3 and Claudin-11, and barrier functionality was examined by biotin tracer permeability. Immunolocalization of Claudin-3 and Claudin-11 was extensive at wild-type (wt) Sertoli cell TJs, which functionally excluded permeability tracer. In contrast, seminiferous tubules of hpg testes lacked Claudin-3, but Claudin-11 protein was present in adluminal regions of Sertoli cells. Biotin tracer permeated throughout these tubules, demonstrating dysfunctional TJs. In hpg+tgFSH testes, Claudin-3 was generally absent, but Claudin-11 had redistributed basally toward the TJs, where function was variable. In hpg testes, DHT treatment stimulated the redistribution of Claudin-11 protein toward the basal region of Sertoli cells by Day 2, increased Cldn3 and Cldn11 mRNA expression, then induced the formation of functional TJs containing both proteins by Day 10. In hpg+tgFSH testes, TJ protein redistribution was accelerated and functional TJs formed by Day 2 of DHT treatment. We conclude that androgen stimulates initial Sertoli cell TJ formation and function in mice, whereas FSH activity is insufficient alone, but augments androgen-induced TJ function.
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Gonadotropins regulate rat testicular tight junctions in vivo.
Endocrinology, 2010Co-Authors: Mark J. Mccabe, Sarah J Meachem, Gerard A. Tarulli, Peter M. Smooker, David Robertson, Peter G StantonAbstract:Sertoli cell tight junctions (TJs) are an essential component of the blood-testis barrier required for spermatogenesis; however, the role of gonadotropins in their maintenance is unknown. This study aimed to investigate the effect of gonadotropin suppression and short-term replacement on TJ function and TJ protein (occludin and Claudin-11) expression and localization, in an adult rat model in vivo. Rats (n = 10/group) received the GnRH antagonist, acyline, for 7 wk to suppress gonadotropins. Three groups then received for 7 d: 1) human recombinant FSH, 2) human chorionic gonadotropin (hCG) and rat FSH antibody (to study testicular androgen stimulation alone), and 3) hCG alone (to study testicular androgen and pituitary FSH production). TJ proteins were assessed by real-time PCR, Western blot analysis, and immunohistochemistry, whereas TJ function was assessed with a biotin permeation tracer. Acyline treatment significantly reduced testis weights, serum androgens, LH and FSH, and adluminal germ cells (pachytene spermatocyte, round and elongating spermatids). In contrast to controls, acyline induced seminiferous tubule permeability to biotin, loss of tubule lumens, and loss of occludin, but redistribution of Claudin-11, immunostaining. Short-term hormone replacement stimulated significant recoveries in adluminal germ cell numbers. In hCG ± FSH antibody-treated rats, occludin and Claudin-11 protein relocalized at the TJ, but such relocalization was minimal with FSH alone. Tubule lumens also reappeared, but most tubules remained permeable to biotin tracer, despite the presence of occludin. It is concluded that gonadotropins maintain Sertoli cell TJs in the adult rat via a mechanism that includes the localization of occludin and Claudin-11 at functional TJs.
Myung Chan Gye - One of the best experts on this subject based on the ideXlab platform.
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Changes in Inflammatory Cytokines Accompany Deregulation of Claudin-11, Resulting in Inter-Sertoli Tight Junctions in Varicocele Rat Testes
Journal of Urology, 2016Co-Authors: Jong Kwan Park, Myung Chan GyeAbstract:Purpose: To elucidate the changes that occur in the blood-testis barrier during varicocele we examined changes in Cldn11 (Claudin-11), an element of the blood-testis barrier, as well as steroidogenesis and proinflammatory cytokines in a model of varicocele rat testes.Materials and Methods: Male rats with experimentally induced varicocele were sacrificed 4 weeks after operation. Testicular histology and blood testosterone concentrations were examined. The expression of tight junctions, steroidogenic enzymes, apoptosis and immune cell markers, and proinflammatory cytokines in the testes were evaluated by reverse transcriptase-polymerase chain reaction, Western blot and immunohistochemistry.Results: Weight and Johnsen scores of varicocele testes were lower than those of normal testes. mRNA expression of Bad and Bax increased whereas Bcl-xl and Bcl2 mRNA decreased in varicocele testes compared to controls. Although blood testosterone did not change, Leydig cell 3βHsd immunoreactivity, testicular 3βHsd6 and 17...
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Claudin 11 Inter-Sertoli Tight Junctions in the Testis of the Korean Soft-Shelled Turtle (Pelodiscus maackii)
Biology of Reproduction, 2015Co-Authors: Chan-jin Park, Jae Eun Lee, Myung Chan GyeAbstract:Expression of Claudin 11 (CLDN11), a tight junction (TJ) protein, was examined in the Korean soft-shelled turtle (Pelodiscus maackii) testis. Spermatogenesis began during the breeding season and peaked at the end of the breeding season. Spermiation started in summer and peaked in autumn. The deduced amino acid sequence of P. maackii CLDN11 was similar to those of avian and mammalian species. During the nonbreeding season when spermatogenesis and testosterone production were active, testicular Cldn11 levels were high. In the seminiferous epithelium, strong, wavy CLDN11 strands parallel to the basement membrane delaminate the spermatogonia, and early spermatocytes are in the open compartment. Otherwise, CLDN11 was found beneath the early spermatocytes and in the Sertoli cell cytoplasm. Punctate zonula occludens 1 (ZO-1) immunoreactivity was found within the CLDN11 strands parallel to the basement membrane or at the outermost periphery of the seminiferous epithelium close to the basal lamina. During the breeding season, when circulating testosterone levels and spermatogenic activity was low, testicular CLDN11 level was lower than those during the nonbreeding season. CLDN11 was found at apicolateral contact sites between adjacent Sertoli cells devoid of the postmeiotic germ cells. At this time, lanthanum tracer diffused to the adluminal compartment of seminiferous epithelium. In cultured testis tissues, testosterone propionate significantly increased the level of Cldn11 mRNA. In P. maackii testis, CLDN11 participates in the development of the blood-testis barrier (BTB), where the CLDN11 expression was coupled with spermatogenic activity and circulating androgen levels, indicating the conserved nature of TJs expressing CLDN11 at the BTB in amniotes.
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Claudin-11 expression increased in spermatogenic defect in human testes.
Fertility and Sterility, 2011Co-Authors: Won Heum Nah, Jae Eun Lee, Hyun Jun Park, Nam Cheol Park, Myung Chan GyeAbstract:Expression of Claudin-11, which builds up blood–testis barrier (BTB), was increased in decreased spermatogenesis, including in hypospermatogenesis, spermatocytic and maturation arrest, and Sertoli cell only (SCO) testes. Increased Claudin-11 immunoreactivity was observed at the inter-Sertoli tight junctions in maturation arrest and in the cytoplasm of Sertoli cells in SCO. The late spermatogenic wave may negatively regulate Claudin-11 gene activation and the subcellular localization of Claudin-11 in Sertoli cells, thus altering the BTB in the human testis.
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Expression of Claudin-1 and -11 in immature and mature pheasant (Phasianus colchicus) testes.
Theriogenology, 2011Co-Authors: Chan-jin Park, Sara Shim, J.e. Lee, W.h. Nah, K.j. Choi, Myung Chan GyeAbstract:The expression of Claudin-1 and -11, tight junctions (TJs) proteins was examined in immature and adult pheasant (Phasianus colchicus) testes. Claudin-1 and -11 cDNA were highly similar to those of human, mice, and chicken. Claudin-1 mRNA and protein (21 kDa) levels in immature testes were higher than those of adult testis. In immature testes until 6 weeks of age, Claudin-1 was found at contacts between adjacent Sertoli cells and between Sertoli cells and germ cells. In adult testis, Claudin-1 was found in early spermatocytes migrating the blood testis barrier (BTB). Blood vessels were positive for Claudin-1. Claudin-11 mRNA and protein (21 kDa) increased during adulthood development of testis. In immature testis, Claudin-11 was found in apicolateral contacts between adjacent Sertoli cells, indicating its involvement in cell adhesion in immature testis. In adult testis, strong wavy Claudin-11 immunoreactivity was parallel to basal lamina at the basal part of seminiferous epithelium, indicating that Claudin-11 at the inter-Sertoli TJs may act as a structural element of the BTB. Weak Claudin-1 and -11 immunoreactivity at contacts between Sertoli cells to elongating/elongated spermatids, meiotic germ cells, and basal lamina suggests that they also participate in the cell–cell and cell–extracellular matrix adhesion in pheasant testis. Testosterone increased Claudin-11 mRNA in testis organ culture and Sertoli cell primary culture, suggesting positive regulation of Claudin-11 gene by androgen in Sertoli cells of pheasant testis. This is the first report on the Claudins expression at BTB in avian testis.
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Postnatal changes in the expression of Claudin-11 in the testes and excurrent ducts of the domestic rabbit (Oryctolagus cuniculus domesticus).
Journal of Andrology, 2010Co-Authors: Chan-jin Park, Jae Eun Lee, Hyun Jun Park, Nam Cheol Park, Sara Shim, Dong Min Kim, Myung Chan GyeAbstract:ABSTRACT: We examined the expression of Claudin-11 (CLDN11) in the testes and male reproductive tracts of rabbits. The rabbit CLDN11 cDNA sequences were nearly identical with human, mouse, and bovine CLDN11. The levels of CLDN11 mRNA and protein (22 kDa) were markedly increased in the testis during adult development. On postnatal day (PND) 10, CLDN11 was colocalized with ZO-1 at the lateral contacts between adjacent Sertoli cells and was perpendicular to the basal lamina. In adult testis on PND 180, CLDN11 was codistributed with ZO1, and the pattern of immunoreactivity consisted of wavy linear tracts parallel to the basal lamina, which was different according to the spermatogenic stage. These results suggest that CLDN11 participates in inter–Sertoli cell tight junctions (TJs) at the blood-testis barrier in adult rabbits. CLDN11 was also found in the basal regions of Sertoli cells adjacent to the basal lamina in adult testis, suggesting that CLDN11 also participates in the adhesion between Sertoli cells and the basal lamina. CLDN11 mRNA and protein expressions were decreased in the adult epididymis compared with those in immature animals. In adults, CLDN11 mRNA levels were relatively high in the efferent duct, followed by those in the vas deferens, proximal corpus, and distal cauda, although low levels were observed in the initial segment and caput. On PND 10, CLDN11 immunoreactivity was identified at the apicolateral contacts between adjacent epithelial cells in the epididymis and vas deferens. In adults, CLDN11 was found in the nonciliated cells in the efferent duct and at the lateral contacts in the epithelial cells in the epididymal segments. In the caput, CLDN11 was found at the apicolateral contacts between adjacent epithelial cells, but expression was weak to negligible in the corpus of the vas deferens. CLDN11 may play an important role in TJs and cell adhesion in immature rabbit excurrent duct epithelia. In adult rabbits, CLDN11 in efferent duct epithelium and epididymal epithelium may contribute to the specific environment for sperm maturation.
Alexander Gow - One of the best experts on this subject based on the ideXlab platform.
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Absence of Claudin 11 in CNS Myelin Perturbs Behavior and Neurotransmitter Levels in Mice.
Scientific Reports, 2018Co-Authors: Kathleen J. Maheras, Marcello Peppi, Farhad Ghoddoussi, Matthew P. Galloway, Shane A. Perrine, Alexander GowAbstract:Neuronal origins of behavioral disorders have been examined for decades to construct frameworks for understanding psychiatric diseases and developing useful therapeutic strategies with clinical application. Despite abundant anecdotal evidence for white matter etiologies, including altered tractography in neuroimaging and diminished oligodendrocyte-specific gene expression in autopsy studies, mechanistic data demonstrating that dysfunctional myelin sheaths can cause behavioral deficits and perturb neurotransmitter biochemistry have not been forthcoming. At least in part, this impasse stems from difficulties in identifying model systems free of degenerative pathology to enable unambiguous assessment of neuron biology and behavior in a background of myelin dysfunction. Herein we examine myelin mutant mice lacking expression of the Claudin11 gene in oligodendrocytes and characterize two behavioral endophenotypes: perturbed auditory processing and reduced anxiety/avoidance. Importantly, these behaviors are associated with increased transmission time along myelinated fibers as well as glutamate and GABA neurotransmitter imbalances in auditory brainstem and amygdala, in the absence of neurodegeneration. Thus, our findings broaden the etiology of neuropsychiatric disease to include dysfunctional myelin, and identify a preclinical model for the development of novel disease-modifying therapies.
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Claudin-11 Tight Junctions in Myelin Are a Barrier to Diffusion and Lack Strong Adhesive Properties
Biophysical Journal, 2015Co-Authors: Andrew R. Denninger, Alexander Gow, Andrew M. Breglio, Kathleen J. Maheras, G. Leduc, Viviana Cristiglio, Bruno Demé, Daniel A. KirschnerAbstract:The radial component is a network of interlamellar tight junctions (TJs) unique to central nervous system myelin. Ablation of Claudin-11, a TJ protein, results in the absence of the radial component and compromises the passive electrical properties of myelin. Although TJs are known to regulate paracellular diffusion, this barrier function has not been directly demonstrated for the radial component, and some evidence suggests that the radial component may also mediate adhesion between myelin membranes. To investigate the physical properties of Claudin-11 TJs, we compared fresh, unfixed Claudin 11-null and control nerves using x-ray and neutron diffraction. In Claudin 11-null tissue, we detected no changes in myelin structure, stability, or membrane interactions, which argues against the notion that myelin TJs exhibit significant adhesive properties. Moreover, our osmotic stressing and D2O-H2O exchange experiments demonstrate that myelin lacking Claudin-11 is more permeable to water and small osmolytes. Thus, our data indicate that the radial component serves primarily as a diffusion barrier and elucidate the mechanism by which TJs govern myelin function.
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Phenotyping the Claudin 11 deficiency in testis: from histology to immunohistochemistry.
Methods in Molecular Biology, 2011Co-Authors: Séverine Mazaud-guittot, Alexander Gow, Brigitte Le Magueresse-battistoniAbstract:The testis is a heterogeneous organ that comprises a number of cell types, including germ cells at -different stages in their maturation, differentiated neighbor nursing cells, and endocrine somatic cells. Despite such cellular heterogeneity the testis is highly organized, with germ cell development and differentiation being compartmentalized into the interconnected tubular network of the seminiferous epithelium. Intratesticular scaffolds rely heavily on the basement membrane of the seminiferous tubules while germ cell development inside the seminiferous epithelium is critically dependent on the Blood Testis Barrier (BTB). The BTB is a macromolecular tight junction complex generated by somatic Sertoli cells within the seminiferous epithelium. The BTB divides the seminiferous epithelium into two compartments: the basal compartment, which delineates a niche for the proliferation and renewal of spermatogonia; and the adluminal compartment, where differentiating germ cells undergo meiosis and spermiogenesis. The BTB is unique in mammalian tissues because it is cyclically reconstructed during the spermatogenic cycle as preleptotene spermatocytes migrate from the basal compartment to the adluminal compartment and enter meiosis. In mouse, the loss of the BTB in the absence of the Claudin 11 protein causes azoospermia and leads to infertility. Specifically, cldn11 deficiency results in sloughing of the cells of the seminiferous epithelium into the lumen. Understanding this pathophysiology has involved histological examination of the tissue defects as well as immunohistological characterization. Here, we present a comparative study of several modifications to the classical Hematoxylin-Eosin stain that may improve the diagnostic usefulness of this technique, as well as the use of several selective markers to identify testicular cell types.
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Claudin 11 Deficiency in Mice Results in Loss of the Sertoli Cell Epithelial Phenotype in the Testis
Biology of Reproduction, 2010Co-Authors: Séverine Mazaud-guittot, Alexander Gow, Emmanuelle Meugnier, Sandra Pesenti, Hubert Vidal, Brigitte Le Magueresse-battistoniAbstract:Tissue integrity relies on barriers formed between epithelial cells. In the testis, the barrier is formed at the initiation of puberty by a tight junction complex between adjacent Sertoli cells, thereby defining an adluminal compartment where meiosis and spermiogenesis occur. Claudin 11 is an obligatory protein for tight junction formation and barrier integrity in the testis. It is expressed by Sertoli cells, and spermatogenesis does not proceed beyond meiosis in its absence, resulting in male sterility. Sertoli cell maturation—arrest of proliferation and expression of proteins to support germ cell development—parallels tight junction assembly; however, the pathophysiology underlying the loss of tight junctions in the mature testis remains largely undefined. Here, using immunohistochemistry and microarrays we demonstrate that adult Cldn11−/− mouse Sertoli cells can proliferate while maintaining expression of mature markers. Sertoli cells detach from the basement membrane, acquire a fibroblast cell shape, are eliminated through the lumen together with apoptotic germ cells, and are found in epididymis. These changes are associated with tight junction regulation as well as actin-related and cell cycle gene expression. Thus, Cldn11−/− Sertoli cells exhibit a unique phenotype whereby loss of tight junction integrity results in loss of the epithelial phenotype.
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Tight junctions potentiate the insulative properties of small CNS myelinated axons.
Journal of Cell Biology, 2008Co-Authors: Jérôme Devaux, Alexander GowAbstract:Claudin family proteins form the physical barriers of tight junctions (TJs) and regulate paracellular diffusion across polarized epithelia. In addition to these heterotypic TJs, Claudin 11 forms autotypic TJs comprising the radial component of central nervous system myelin. The exact function of these TJs has been unclear, although their location at the membrane perimeter is well sited to regulate diffusion between the interstitium and intramyelinic space. In this study, we demonstrate that Claudin 11 affords rapid nerve conduction principally for small diameter myelinated axons. Claudin 11–null mice have preserved myelin and axonal architecture, but as much as a 60% decrease in conduction. They also have increased action potential thresholds and activated internodal potassium channels. These data indicate that TJs modulate the biophysical properties of myelin. Computational modeling reveals that Claudin 11 reduces current flow through myelin and moderates its capacitive charging. Together, our data shed new light on myelin structural components and our understanding of the biology and pathophysiology of this membrane.
Janet M. Bronstein - One of the best experts on this subject based on the ideXlab platform.
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osp Claudin 11 forms a complex with a novel member of the tetraspanin super family and β1 integrin and regulates proliferation and migration of oligodendrocytes
Journal of Cell Biology, 2001Co-Authors: Seema K Tiwariwoodruff, Alex G Buznikov, Trung Vu, Paul E Micevych, Kendall Chen, Harley I Kornblum, Janet M. BronsteinAbstract:Oligodendrocyte-specific protein (OSP)/Claudin-11 is a major component of central nervous system myelin and forms tight junctions (TJs) within myelin sheaths. TJs are essential for forming a paracellular barrier and have been implicated in the regulation of growth and differentiation via signal transduction pathways. We have identified an OSP/Claudin-11–associated protein (OAP)1, using a yeast two-hybrid screen. OAP-1 is a novel member of the tetraspanin superfamily, and it is widely expressed in several cell types, including oligodendrocytes. OAP-1, OSP/Claudin-11, and β1 integrin form a complex as indicated by coimmunoprecipitation and confocal immunocytochemistry. Overexpression of OSP/Claudin-11 or OAP-1 induced proliferation in an oligodendrocyte cell line. Anti–OAP-1, anti–OSP/Claudin-11, and anti–β1 integrin antibodies inhibited migration of primary oligodendrocytes, and migration was impaired in OSP/Claudin-11–deficient primary oligodendrocytes. These data suggest a role for OSP/Claudin-11, OAP-1, and β1 integrin complex in regulating proliferation and migration of oligodendrocytes, a process essential for normal myelination and repair.
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Osp/Claudin-11 Forms a Complex with a Novel Member of the Tetraspanin Super Family and β1 Integrin and Regulates Proliferation and Migration of Oligodendrocytes
Journal of Cell Biology, 2001Co-Authors: Seema K. Tiwari-woodruff, Alex G Buznikov, Paul E Micevych, Kendall Chen, Harley I Kornblum, Janet M. BronsteinAbstract:Oligodendrocyte-specific protein (OSP)/Claudin-11 is a major component of central nervous system myelin and forms tight junctions (TJs) within myelin sheaths. TJs are essential for forming a paracellular barrier and have been implicated in the regulation of growth and differentiation via signal transduction pathways. We have identified an OSP/Claudin-11–associated protein (OAP)1, using a yeast two-hybrid screen. OAP-1 is a novel member of the tetraspanin superfamily, and it is widely expressed in several cell types, including oligodendrocytes. OAP-1, OSP/Claudin-11, and β1 integrin form a complex as indicated by coimmunoprecipitation and confocal immunocytochemistry. Overexpression of OSP/Claudin-11 or OAP-1 induced proliferation in an oligodendrocyte cell line. Anti–OAP-1, anti–OSP/Claudin-11, and anti–β1 integrin antibodies inhibited migration of primary oligodendrocytes, and migration was impaired in OSP/Claudin-11–deficient primary oligodendrocytes. These data suggest a role for OSP/Claudin-11, OAP-1, and β1 integrin complex in regulating proliferation and migration of oligodendrocytes, a process essential for normal myelination and repair.
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Developmental expression of OSP/Claudin-11.
Journal of Neuroscience Research, 2000Co-Authors: Janet M. Bronstein, Kendall Chen, Seema K. Tiwari-woodruff, Harley I KornblumAbstract:Oligodendrocyte-specific protein (OSP/Claudin-11) is a major component of CNS myelin and has been recently added to the Claudin family of tight junction proteins. In this study, the developmental expression of OSP/Claudin-11 was determined using in situ hybridization, immunohistochemistry (IH), and Western blot analysis. OSP/Claudin-11 mRNA was expressed in a bimodal fashion. During prenatal development, OSP/Claudin-11 mRNA was abundant in developing meninges, in areas adjacent to cartilage, and in mesoderm. In postnatal animals, OSP/Claudin-11 was expressed primarily in developing oligodendrocytes and to a lesser extent, in testes. Double-labeled IH using O2-A progenitor cells revealed that OSP/Claudin-11 expression occurs from the early progenitor stage and continues in mature oligodendrocytes. Electron microscopic IH localized OSP/Claudin-11 to laminar myelin in the adult CNS. Western blot analysis of OSP/Claudin-11 in developing brain revealed the expression of two separate transcripts that were developmentally regulated. These data demonstrate that OSP/Claudin-11 expression is highly regulated during development and, therefore, may play an important role in growth and differentiation of oligodendrocytes and other cells outside the CNS. J. Neurosci. Res. 3:284–290, 2000 © 2000 Wiley-Liss, Inc.
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developmental expression of osp Claudin 11
Journal of Neuroscience Research, 2000Co-Authors: Janet M. Bronstein, Seema K Tiwariwoodruff, Kendall Chen, Harley I KornblumAbstract:Oligodendrocyte-specific protein (OSP/Claudin-11) is a major component of CNS myelin and has been recently added to the Claudin family of tight junction proteins. In this study, the developmental expression of OSP/Claudin-11 was determined using in situ hybridization, immunohistochemistry (IH), and Western blot analysis. OSP/Claudin-11 mRNA was expressed in a bimodal fashion. During prenatal development, OSP/Claudin-11 mRNA was abundant in developing meninges, in areas adjacent to cartilage, and in mesoderm. In postnatal animals, OSP/Claudin-11 was expressed primarily in developing oligodendrocytes and to a lesser extent, in testes. Double-labeled IH using O2-A progenitor cells revealed that OSP/Claudin-11 expression occurs from the early progenitor stage and continues in mature oligodendrocytes. Electron microscopic IH localized OSP/Claudin-11 to laminar myelin in the adult CNS. Western blot analysis of OSP/Claudin-11 in developing brain revealed the expression of two separate transcripts that were developmentally regulated. These data demonstrate that OSP/Claudin-11 expression is highly regulated during development and, therefore, may play an important role in growth and differentiation of oligodendrocytes and other cells outside the CNS. J. Neurosci. Res. 3:284–290, 2000 © 2000 Wiley-Liss, Inc.
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Involvement of OSP/Claudin-11 in oligodendrocyte membrane interactions: role in biology and disease.
Journal of Neuroscience Research, 2000Co-Authors: Janet M. Bronstein, Alex G Buznikov, Seema K. Tiwari-woodruff, David B. StevensAbstract:Oligodendrocyte-specific protein (OSP/Claudin-11) is a four transmembrane protein concentrated in central nervous system myelin. Recent evidence has emerged suggesting that OSP/Claudin-11 is involved in membrane interactions at tight junctions and with the extracellular matrix. OSP/Claudin-11 seems to modulate proliferation and migration of oligodendrocytes presumably through these interactions. Furthermore, evidence is presented implicating OSP/Claudin-11 as an autoantigen in the development of autoimmune demyelinating disease. J. Neurosci. Res. 59:706–711, 2000 © 2000 Wiley-Liss, Inc.
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Gonadotropin suppression in men leads to a reduction in Claudin-11 at the Sertoli cell tight junction
Human Reproduction, 2016Co-Authors: Mark J. Mccabe, Sarah J Meachem, Robert I Mclachlan, Gerard A. Tarulli, Geraldine Laven-law, K.l. Matthiesson, Marcel E. Dinger, Peter G StantonAbstract:STUDY QUESTION: Are Sertoli cell tight junctions (TJs) disrupted in men undergoing hormonal contraception? SUMMARY ANSWER: 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. WHAT IS KNOWN ALREADY: 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. STUDY DESIGN SIZE DURATION: 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 5alpha-reductase inhibitor dutasteride (D). A control group consisted of seven additional men with three archived samples available for this study. PARTICIPANTS/MATERIALS SETTINGS METHODS: Immunohistochemical localization of Claudin-11 (TJ) and other junctional type markers [ZO-1 (cytoplasmic plaque) beta-catenin (adherens junction) connexin-43 (gap junction) vinculin (ectoplasmic specialization) and beta-actin (cytoskeleton)] and quantitative PCR was conducted using matched frozen testis tissue. MAIN RESULTS AND THE ROLE OF CHANCE: 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 40% of control. Changes in localization of connexin-43 and vinculin were also observed (smaller effects than for Claudin-11) but ZO-1 beta-catenin and beta-actin did not differ compared with control. LIMITATIONS REASONS FOR CAUTION: 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. WIDER IMPLICATIONS OF THE FINDINGS: 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. STUDY FUNDING/COMPETING INTERESTS: National Health and Medical Research Council (Australia) Program Grants 241000 and 494802; Research Fellowship 1022327 (to R.I.M.) and the Victorian Governments Operational Infrastructure Support Program. None of the authors have any conflicts to disclose. TRIAL REGISTRATION NUMBER: Not applicable. (c) The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions please email: journals.permissions@oup.com.
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Claudin-11 and occludin are major contributors to Sertoli cell tight junction function, in vitro
Asian Journal of Andrology, 2016Co-Authors: Mark J. Mccabe, Caroline F.h. Foo, Marcel E. Dinger, Peter M. Smooker, Peter G StantonAbstract:The Sertoli cell tight junction (TJ) is the key component of the blood-testis barrier, where it sequesters developing germ cells undergoing spermatogenesis within the seminiferous tubules. Hormonally regulated Claudin-11 is a critical transmembrane protein involved in barrier function and its murine knockout results in infertility. We aimed to assess quantitatively the significance of the contribution of Claudin-11 to TJ function, in vitro, using siRNA-mediated gene silencing. We also conducted an analysis of the contribution of occludin, another intrinsic transmembrane protein of the TJ. Silencing of Claudin-11 and/or occludin was conducted using siRNA in an immature rat Sertoli cell culture model. Transepithelial electrical resistance was used to assess quantitatively TJ function throughout the culture. Two days after siRNA treatment, cells were fixed for immunocytochemical localization of junction proteins or lyzed for RT-PCR assessment of mRNA expression. Silencing of Claudin-11, occludin, or both resulted in significant decreases in TJ function of 55% (P < 0.01), 51% (P < 0.01), and 62% (P < 0.01), respectively. Data were concomitant with significant decreases in mRNA expression and marked reductions in the localization of targeted proteins to the Sertoli cell TJ. We provide quantitative evidence that Claudin-11 contributes significantly (P < 0.01) to Sertoli cell TJ function in vitro. Interestingly, occludin, which is hormonally regulated but not implicated in infertility until late adulthood, is also a significant (P < 0.01) contributor to barrier function. Our data are consistent with in vivo studies that clearly demonstrate a role for these proteins in maintaining normal TJ barrier structure and function.
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androgen initiates sertoli cell tight junction formation in the hypogonadal hpg mouse
Biology of Reproduction, 2012Co-Authors: Peter G Stanton, Mark J. Mccabe, Charles M Allan, Peter K Nicholls, Kirsten J MctavishAbstract:Sertoli cell tight junctions (TJs) form at puberty as a major component of the blood-testis barrier (BTB), which is essential for spermatogenesis. This study characterized the hormonal induction of functional Sertoli cell TJ formation in vivo using the gonadotropin-deficient hypogonadal (hpg) mouse that displays prepubertal spermatogenic arrest. Androgen actions were determined in hpg mice treated for 2 or 10 days with dihydrotestosterone (DHT). Follicle-stimulating hormone (FSH) actions were studied in hpg mice expressing transgenic human FSH (hpg+tgFSH) with or without DHT treatment. TJ formation was examined by mRNA expression and immunolocalization of TJ proteins Claudin-3 and Claudin-11, and barrier functionality was examined by biotin tracer permeability. Immunolocalization of Claudin-3 and Claudin-11 was extensive at wild-type (wt) Sertoli cell TJs, which functionally excluded permeability tracer. In contrast, seminiferous tubules of hpg testes lacked Claudin-3, but Claudin-11 protein was present in adluminal regions of Sertoli cells. Biotin tracer permeated throughout these tubules, demonstrating dysfunctional TJs. In hpg+tgFSH testes, Claudin-3 was generally absent, but Claudin-11 had redistributed basally toward the TJs, where function was variable. In hpg testes, DHT treatment stimulated the redistribution of Claudin-11 protein toward the basal region of Sertoli cells by Day 2, increased Cldn3 and Cldn11 mRNA expression, then induced the formation of functional TJs containing both proteins by Day 10. In hpg+tgFSH testes, TJ protein redistribution was accelerated and functional TJs formed by Day 2 of DHT treatment. We conclude that androgen stimulates initial Sertoli cell TJ formation and function in mice, whereas FSH activity is insufficient alone, but augments androgen-induced TJ function.
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Gonadotropins regulate rat testicular tight junctions in vivo.
Endocrinology, 2010Co-Authors: Mark J. Mccabe, Sarah J Meachem, Gerard A. Tarulli, Peter M. Smooker, David Robertson, Peter G StantonAbstract:Sertoli cell tight junctions (TJs) are an essential component of the blood-testis barrier required for spermatogenesis; however, the role of gonadotropins in their maintenance is unknown. This study aimed to investigate the effect of gonadotropin suppression and short-term replacement on TJ function and TJ protein (occludin and Claudin-11) expression and localization, in an adult rat model in vivo. Rats (n = 10/group) received the GnRH antagonist, acyline, for 7 wk to suppress gonadotropins. Three groups then received for 7 d: 1) human recombinant FSH, 2) human chorionic gonadotropin (hCG) and rat FSH antibody (to study testicular androgen stimulation alone), and 3) hCG alone (to study testicular androgen and pituitary FSH production). TJ proteins were assessed by real-time PCR, Western blot analysis, and immunohistochemistry, whereas TJ function was assessed with a biotin permeation tracer. Acyline treatment significantly reduced testis weights, serum androgens, LH and FSH, and adluminal germ cells (pachytene spermatocyte, round and elongating spermatids). In contrast to controls, acyline induced seminiferous tubule permeability to biotin, loss of tubule lumens, and loss of occludin, but redistribution of Claudin-11, immunostaining. Short-term hormone replacement stimulated significant recoveries in adluminal germ cell numbers. In hCG ± FSH antibody-treated rats, occludin and Claudin-11 protein relocalized at the TJ, but such relocalization was minimal with FSH alone. Tubule lumens also reappeared, but most tubules remained permeable to biotin tracer, despite the presence of occludin. It is concluded that gonadotropins maintain Sertoli cell TJs in the adult rat via a mechanism that includes the localization of occludin and Claudin-11 at functional TJs.