Biology of desmosome-gap junctions in the testis

Summary

Principal Investigator: Dolores D Mruk
Abstract: DESCRIPTION (provided by applicant): One of the best-studied phenomena in cell biology is the adhesion of cells to form an organized epithelium, which is facilitated by adherens junctions and desmosomes. In the testis, morphological studies in the 1970s reported the presence of desmosome-gap junctions (also known as desmosome-like junctions) between adjacent Sertoli cells at the blood-testis barrier, as well as between Sertoli cells and germ cells. Unfortunately, since this time there has not been a single report addressing the biology of desmosome-gap junctions and their significance in spermatogenesis. This application aims to fill this gap by investigating desmosome-gap junction dynamics in the mammalian testis. A survey by RT-PCR revealed that Sertoli and germ cells express several desmosome target genes, including desmoglein-2, desmocollin-2, plakophilin and desmoplakin. Moreover, when Sertoli cells were cultured at high density in vitro, thereby forming a polarized epithelium with functional cell junctions reminiscent of the blood-testis barrier in vivo, desmosome-like structures were visible by electron microscopy. This coincided with an up-regulation in the levels of several desmosome proteins, illustrating that the testis is equipped with the necessary 'building blocks'to establish functional desmosome-like junctions in vivo. In this application, the P.I. has two aims. First, using a well-characterized Sertoli cell in vitro model, the P.I. will investigate crosstalk between desmosome-like and gap junctions. To address this aim, the P.I. will use crosslinking and coimmunoprecipitation, followed by immunofluorescence microscopy, to identify protein-protein interactions common to both desmosome-like and gap junctions. Finally, the function of gap junctions will be assessed in functional experiments when two key desmosomal cadherins, namely desmoglein-2 and desmocollin-2, are silenced in Sertoli cells in vitro by RNAi. Second, the P.I. will examine the role of desmosome-gap junctions in blood-testis barrier function. Specifically, the P.I. will knockdown desmoglein-2 and desmocollin-2 in Sertoli cells and assess the function of the blood-testis barrier by transepithelial electrical resistance (TER) measurements, immunofluorescence and electron microscopy. Preliminary results presented herein, which showed changes in JAM-A, ZO-1 and CAR when only desmoglein-2 was silenced in Sertoli cells in vitro, support this Specific Aim. Finally, the P.I. will investigate in part the mechanism underlying blood- testis barrier restructuring following desmoglein-2 and desmocoolin-2. The P.I. believes these results will be welcomed in the field because they would represent the first findings on the biology of desmosome-gap junctions in the testis since their initial morphological identification. PUBLIC HEALTH RELEVANCE: Adhesion between adjacent Sertoli cells in the seminiferous epithelium of the testis in mammals is needed for spermatogenesis and fertility. If Sertoli cell adhesion at the level of the blood-testis barrier is compromised, germ cells deplete prematurely from the epithelium, and infertility can result. The study of desmosome-gap junctions in the testis will yield new and important insights into the biology of spermatogenesis.
Funding Period: ----------------2009 - ---------------2011-
more information: NIH RePORT

Top Publications

  1. pmc Sertolin mediates blood-testis barrier restructuring
    Michelle W M Li
    Center for Biomedical Research, Population Council, New York, New York 10065
    Endocrinology 155:1520-31. 2014
  2. pmc Intercellular adhesion molecule-1 is a regulator of blood-testis barrier function
    Xiang Xiao
    Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    J Cell Sci 125:5677-89. 2012
  3. pmc Intercellular adhesion molecule-2 is involved in apical ectoplasmic specialization dynamics during spermatogenesis in the rat
    Xiang Xiao
    Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    J Endocrinol 216:73-86. 2013
  4. pmc Signalling pathways regulating the blood-testis barrier
    Pearl P Y Lie
    Center for Biomedical Research, Population Council, New York, NY 10065, USA
    Int J Biochem Cell Biol 45:621-5. 2013
  5. pmc Rictor/mTORC2 regulates blood-testis barrier dynamics via its effects on gap junction communications and actin filament network
    Ka Wai Mok
    Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, USA
    FASEB J 27:1137-52. 2013
  6. pmc Gap junctions and blood-tissue barriers
    Michelle W M Li
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, New York, New York, USA
    Adv Exp Med Biol 763:260-80. 2012
  7. ncbi Intercellular adhesion molecule 1: recent findings and new concepts involved in mammalian spermatogenesis
    Dolores D Mruk
    Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, United States Electronic address
    Semin Cell Dev Biol 29:43-54. 2014
  8. ncbi Adjudin, a potential male contraceptive, exerts its effects locally in the seminiferous epithelium of mammalian testes
    Ka Wai Mok
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, New York 10065, USA
    Reproduction 141:571-80. 2011
  9. ncbi Drug transporters and blood--testis barrier function
    Linlin Su
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065, USA
    J Endocrinol 209:337-51. 2011
  10. pmc Regulation of spermiogenesis, spermiation and blood-testis barrier dynamics: novel insights from studies on Eps8 and Arp3
    C Yan Cheng
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    Biochem J 435:553-62. 2011

Scientific Experts

  • C Yan Cheng
  • Dolores D Mruk
  • Pearl P Y Lie
  • Linlin Su
  • Xiang Xiao
  • Will M Lee
  • Michelle W M Li
  • Ka Wai Mok
  • K W Mok
  • Elissa W P Wong
  • Ilona A Kopera
  • W M Lee
  • Wing Yee Lui
  • Barbara Bilinska

Detail Information

Publications28

  1. pmc Sertolin mediates blood-testis barrier restructuring
    Michelle W M Li
    Center for Biomedical Research, Population Council, New York, New York 10065
    Endocrinology 155:1520-31. 2014
    ..Taken collectively, these results suggest that sertolin may be involved in coordinating spermatid release and BTB restructuring during spermatogenesis in the rat. ..
  2. pmc Intercellular adhesion molecule-1 is a regulator of blood-testis barrier function
    Xiang Xiao
    Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    J Cell Sci 125:5677-89. 2012
    ..These data illustrate the existence of a unique mechanism in the mammalian testis where ICAM-1 can either positively or negatively regulate BTB function...
  3. pmc Intercellular adhesion molecule-2 is involved in apical ectoplasmic specialization dynamics during spermatogenesis in the rat
    Xiang Xiao
    Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    J Endocrinol 216:73-86. 2013
    ..Taken collectively, these results illustrate that ICAM2 plays an important role in apical ES dynamics during spermatogenesis...
  4. pmc Signalling pathways regulating the blood-testis barrier
    Pearl P Y Lie
    Center for Biomedical Research, Population Council, New York, NY 10065, USA
    Int J Biochem Cell Biol 45:621-5. 2013
    ..Herein, we discuss the signaling pathways and mechanisms involved in blood-testis barrier restructuring in the mammalian testis...
  5. pmc Rictor/mTORC2 regulates blood-testis barrier dynamics via its effects on gap junction communications and actin filament network
    Ka Wai Mok
    Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, USA
    FASEB J 27:1137-52. 2013
    ..Rictor knockdown by RNAi was also found to impede Sertoli cell-cell GJ communication, disrupting protein distribution (e.g., occludin, ZO-1) at the BTB, illustrating that rictor is a crucial BTB regulator...
  6. pmc Gap junctions and blood-tissue barriers
    Michelle W M Li
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, New York, New York, USA
    Adv Exp Med Biol 763:260-80. 2012
    ....
  7. ncbi Intercellular adhesion molecule 1: recent findings and new concepts involved in mammalian spermatogenesis
    Dolores D Mruk
    Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, United States Electronic address
    Semin Cell Dev Biol 29:43-54. 2014
    ..In this review, we focus on the biology of intercellular adhesion molecules in the mammalian testis, hoping that this information is useful in the design of future studies. ..
  8. ncbi Adjudin, a potential male contraceptive, exerts its effects locally in the seminiferous epithelium of mammalian testes
    Ka Wai Mok
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, New York 10065, USA
    Reproduction 141:571-80. 2011
    ..In this review, we highlight some of the recent advances and obstacles regarding the possible use of adjudin as a male contraceptive...
  9. ncbi Drug transporters and blood--testis barrier function
    Linlin Su
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065, USA
    J Endocrinol 209:337-51. 2011
    ....
  10. pmc Regulation of spermiogenesis, spermiation and blood-testis barrier dynamics: novel insights from studies on Eps8 and Arp3
    C Yan Cheng
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    Biochem J 435:553-62. 2011
    ....
  11. pmc Spermatogonial stem cells alone are not sufficient to re-initiate spermatogenesis in the rat testis following adjudin-induced infertility
    K W Mok
    Center for Biomedical Research, Population Council, New York, NY 10065, USA
    Int J Androl 35:86-101. 2012
    ..In short, these findings illustrate the critical significance of the BTB for re-initiation of spermatogenesis besides SSC and spermatogonia...
  12. pmc The biology of interleukin-1: emerging concepts in the regulation of the actin cytoskeleton and cell junction dynamics
    Pearl P Y Lie
    Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    Cell Mol Life Sci 69:487-500. 2012
    ..In this review, we highlight new and interesting findings that show IL-1 to be a critical player of restructuring events in the seminiferous epithelium of the testis during spermatogenesis...
  13. pmc The blood-testis barrier and its implications for male contraception
    C Yan Cheng
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    Pharmacol Rev 64:16-64. 2012
    ..Collectively, these findings illustrate multiple potential targets are present at the BTB for innovative contraceptive development and for better delivery of drugs to alleviate toxicant-induced reproductive dysfunction in men...
  14. pmc c-Yes regulates cell adhesion at the blood-testis barrier and the apical ectoplasmic specialization in the seminiferous epithelium of rat testes
    Xiang Xiao
    Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    Int J Biochem Cell Biol 43:651-65. 2011
    ..In summary, c-Yes regulates BTB and apical ES integrity by maintaining proper distribution of integral membrane proteins and actin filament organization at these sites...
  15. ncbi The biology of the desmosome-like junction a versatile anchoring junction and signal transducer in the seminiferous epithelium
    Pearl P Y Lie
    Population Council, Center for Biomedical Research, New York, New York, USA
    Int Rev Cell Mol Biol 286:223-69. 2011
    ..We place special emphasis on the emerging role of desmosome-like junctions as signal transducers during germ cell movement across the seminiferous epithelium...
  16. pmc Crosstalk between desmoglein-2/desmocollin-2/Src kinase and coxsackie and adenovirus receptor/ZO-1 protein complexes, regulates blood-testis barrier dynamics
    Pearl P Y Lie
    Population Council, Center for Biomedical Research, 1230 York Avenue, New York, NY 10065, United States
    Int J Biochem Cell Biol 42:975-86. 2010
    ..We hereby propose a novel regulatory protein complex composed of desmoglein-2, desmocollin-2, c-Src, coxsackie and adenovirus receptor and zonula occludens-1 at the blood-testis barrier...
  17. pmc Cytoskeletal dynamics and spermatogenesis
    Pearl P Y Lie
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    Philos Trans R Soc Lond B Biol Sci 365:1581-92. 2010
    ....
  18. pmc Sertoli-germ cell junctions in the testis: a review of recent data
    Ilona A Kopera
    Population Council, Center for Biomedical Research, 1230 York Avenue, New York, NY 10065, USA
    Philos Trans R Soc Lond B Biol Sci 365:1593-605. 2010
    ..Here, we discuss recent findings relating to these two junction types in the testis, highlighting prospective areas that should be investigated in future studies...
  19. pmc Tight junctions in the testis: new perspectives
    Dolores D Mruk
    Population Council, Center for Biomedical Research, 1230 York Avenue, New York, NY 10065, USA
    Philos Trans R Soc Lond B Biol Sci 365:1621-35. 2010
    ..We also discuss how this information may apply to future studies investigating the movement of preleptotene spermatocytes across the BTB...
  20. pmc Regulation of blood-testis barrier dynamics by TGF-beta3 is a Cdc42-dependent protein trafficking event
    Elissa W P Wong
    Center for Biomedical Research, Population Council, New York, NY 10065, USA
    Proc Natl Acad Sci U S A 107:11399-404. 2010
    ..In summary, Cdc42 is a crucial regulatory component in the TGF-beta3-mediated cascade of events that leads to the disruption of the TJ fibrils above the preleptotene spermatocytes to facilitate their transit...
  21. pmc A local autocrine axis in the testes that regulates spermatogenesis
    C Yan Cheng
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    Nat Rev Endocrinol 6:380-95. 2010
    ..This local regulatory axis is the emerging target for male contraception...
  22. pmc Differential effects of testosterone and TGF-β3 on endocytic vesicle-mediated protein trafficking events at the blood-testis barrier
    Linlin Su
    Center for Biomedical Research, Population Council, New York, NY 10065, USA
    Exp Cell Res 316:2945-60. 2010
    ....
  23. pmc Adjudin-mediated Sertoli-germ cell junction disassembly affects Sertoli cell barrier function in vitro and in vivo
    Linlin Su
    Population Council, Center for Biomedical Research, New York, NY 10065, USA
    Int J Biochem Cell Biol 42:1864-75. 2010
    ..These results illustrate that a unique mechanism exists to maintain blood-testis barrier integrity at all costs, irrespective of the presence of germ cells in the seminiferous epithelium of the testis...
  24. ncbi Drug transporters, the blood-testis barrier, and spermatogenesis
    Linlin Su
    The Mary M Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065, USA
    J Endocrinol 208:207-23. 2011
    ..For example, when drugs (e.g. male contraceptives) that can perturb germ cell adhesion and/or maturation are actively pumped out of the testis or are prevented from entering the apical compartment, such as by efflux pumps...
  25. pmc Emerging role for drug transporters at the blood-testis barrier
    Dolores D Mruk
    Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
    Trends Pharmacol Sci 32:99-106. 2011
    ..Modulation of efflux pump function via specific inhibitors could help to deliver contraceptives to the testis in the future...
  26. ncbi The myotubularin family of lipid phosphatases in disease and in spermatogenesis
    Dolores D Mruk
    Center for Biomedical Research, New York, NY 10065, USA
    Biochem J 433:253-62. 2011
    ....
  27. pmc Interleukin-1alpha is a regulator of the blood-testis barrier
    Pearl P Y Lie
    Center for Biomedical Research, Population Council, New York, NY 10065, USA
    FASEB J 25:1244-53. 2011
    ..As important, an increase in the kinetics of occludin internalization but a decrease in its rate of degradation was noted following IL-1α treatment. These results indicate that IL-1α is a critical regulator of BTB dynamics...
  28. pmc Drug transporter, P-glycoprotein (MDR1), is an integrated component of the mammalian blood-testis barrier
    Linlin Su
    Population Council, Center for Biomedical Research, 1230 York Avenue, NY 10065, USA
    Int J Biochem Cell Biol 41:2578-87. 2009
    ..g., occludin, claudin-11 and JAM-A) was noted when testis lysates from Adjudin-treated rats were used for co-immunoprecipitation experiments, suggesting that P-gp may enhance BTB function during Sertoli-germ cell junction restructuring...