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Wang L, Yan M, Wu S, Mao B, Wong CKC, Ge R, Sun F, Cheng CY. Microtubule Cytoskeleton and Spermatogenesis-Lesson From Studies of Toxicant Models. Toxicol Sci 2020; 177:305-315. [PMID: 32647867 PMCID: PMC7548287 DOI: 10.1093/toxsci/kfaa109] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Studies have shown that mammalian testes, in particular the Sertoli cells, are highly susceptible to exposure of environmental toxicants, such as cadmium, perfluorooctanesulfonate, phthalates, 2,5-hexanedione and bisphenol A. However, important studies conducted by reproductive toxicologists and/or biologists in the past have been treated as toxicology reports per se. Yet, many of these studies provided important mechanistic insights on the toxicant-induced testis injury and reproductive dysfunction, relevant to the biology of the testis and spermatogenesis. Furthermore, recent studies have shown that findings obtained from toxicant models are exceedingly helpful tools to unravel the biology of testis function in particular spermatogenesis, including specific cellular events associated with spermatid transport to support spermiogenesis and spermiation. In this review, we critically evaluate some recent data, focusing primarily on the molecular structure and role of microtubules in cellular function, illustrating the importance of toxicant models to unravel the biology of microtubule cytoskeleton in supporting spermatogenesis, well beyond information on toxicology. These findings have opened up some potential areas of research which should be carefully evaluated in the years to come.
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Affiliation(s)
- Lingling Wang
- The Second Affiliated Hospital and Yuying Children’s Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, Jiangsu 210009, China
| | - Ming Yan
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, Jiangsu 210009, China
| | - Siwen Wu
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, Jiangsu 210009, China
| | - Baiping Mao
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, Jiangsu 210009, China
| | - Chris K C Wong
- Department of Biology, Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon, Hong Kong, China
| | - Renshan Ge
- The Second Affiliated Hospital and Yuying Children’s Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Fei Sun
- Institute of Reproductive Medicine, Nantong University School of Medicine, Nantong, Jiangsu 226001, China
| | - C Yan Cheng
- The Second Affiliated Hospital and Yuying Children’s Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065
- Institute of Reproductive Medicine, Nantong University School of Medicine, Nantong, Jiangsu 226001, China
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2
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Li LX, Wu SW, Yan M, Lian QQ, Ge RS, Cheng CY. Regulation of blood-testis barrier dynamics by the mTORC1/rpS6 signaling complex: An in vitro study. Asian J Androl 2020; 21:365-375. [PMID: 30829292 PMCID: PMC6628733 DOI: 10.4103/aja.aja_126_18] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
During spermatogenesis, developing germ cells that lack the cellular ultrastructures of filopodia and lamellipodia generally found in migrating cells, such as macrophages and fibroblasts, rely on Sertoli cells to support their transport across the seminiferous epithelium. These include the transport of preleptotene spermatocytes across the blood-testis barrier (BTB), but also the transport of germ cells, in particular developing haploid spermatids, across the seminiferous epithelium, that is to and away from the tubule lumen, depending on the stages of the epithelial cycle. On the other hand, cell junctions at the Sertoli cell–cell and Sertoli–germ cell interface also undergo rapid remodeling, involving disassembly and reassembly of cell junctions, which, in turn, are supported by actin- and microtubule-based cytoskeletal remodeling. Interestingly, the underlying mechanism(s) and the involving biomolecule(s) that regulate or support cytoskeletal remodeling remain largely unknown. Herein, we used an in vitro model of primary Sertoli cell cultures that mimicked the Sertoli BTB in vivo overexpressed with the ribosomal protein S6 (rpS6, the downstream signaling protein of mammalian target of rapamycin complex 1 [mTORC1]) cloned into the mammalian expression vector pCI-neo, namely, quadruple phosphomimetic and constitutively active mutant of rpS6 (pCI-neo/p-rpS6-MT) versus pCI-neo/rpS6-WT (wild-type) and empty vector (pCI-neo/Ctrl) for studies. These findings provide compelling evidence that the mTORC1/rpS6 signal pathway exerted its effects to promote Sertoli cell BTB remodeling. This was mediated through changes in the organization of actin- and microtubule-based cytoskeletons, involving changes in the distribution and/or spatial expression of actin- and microtubule-regulatory proteins.
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Affiliation(s)
- Lin-Xi Li
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou 325027, China.,The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Si-Wen Wu
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou 325027, China.,The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Ming Yan
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY 10065, USA.,Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing 210009, China
| | - Qing-Quan Lian
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Ren-Shan Ge
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - C Yan Cheng
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou 325027, China.,The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY 10065, USA
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3
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Wang L, Dou T, Li S, Liu Y. Transcriptome profiling and pathway analysis of the effects of mono-(2-ethylhexyl) phthalate in mouse Sertoli cells. Exp Ther Med 2019; 17:2821-2829. [PMID: 30906470 DOI: 10.3892/etm.2019.7239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 01/28/2019] [Indexed: 01/12/2023] Open
Abstract
Phthalates are confirmed to have toxic effects on the reproductive system and are likely to have further damaging actions in humans. The present study explored the molecular mechanisms of the toxic effect of mono-(2-ethylhexyl) phthalate (MEHP) on mouse Sertoli cells. Cell apoptosis and proliferation assays were used to assess the effects of MEHP on the TM4 Sertoli cell line derived from mouse testes. TM4 cells were treated with two doses of MEHP or left untreated as a control group, followed by RNA extraction and analysis using high-throughput transcriptome sequencing technology. The gene expression profile obtained was then subjected to a bioinformatics analysis to explore the molecular mechanisms of reproductive toxicity. The results revealed that 528 and 269 genes were upregulated in the high- and low-dose MEHP groups of cells compared with the control group, while 148 and 173 genes were downregulated. Gene ontology (GO) analysis indicated that the differently expressed genes were associated with the GO term 'extracellular region' of the cellular component domain in the high and low MEHP groups. Compared with the control group, eight common pathway changes were identified in the high- and low-dose MEHP groups, including 'terpenoid backbone biosynthesis'. Reverse transcription-quantitative polymerase chain reaction analysis was used to validation, and hermetic effects were observed for certain genes. These results provide an important basis and experimental data for further research into the mechanisms of phthalate-induced toxicity.
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Affiliation(s)
- Liqiang Wang
- Key Laboratory of Public Health Safety of The Ministry of Education, School of Public Health, Fudan University, Shanghai 200032, P.R. China.,College of Medical Technology, Shanghai University of Medicine & Health Sciences, Shanghai 201318, P.R. China
| | - Tonghai Dou
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Shuguang Li
- Key Laboratory of Public Health Safety of The Ministry of Education, School of Public Health, Fudan University, Shanghai 200032, P.R. China
| | - Yang Liu
- Shanghai Institute of Quality Inspection and Technical Research, National Quality Supervision and Inspection Center for Food Products (Shanghai), Shanghai 200233, P.R. China
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4
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Ansar S, Abudawood M, Hamed SS, Aleem MM. Sodium Selenite Protects Against Silver Nanoparticle-Induced Testicular Toxicity and Inflammation. Biol Trace Elem Res 2017; 175:161-168. [PMID: 27239677 DOI: 10.1007/s12011-016-0759-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 05/23/2016] [Indexed: 11/26/2022]
Abstract
Metal nanomaterials hold great potential and play an important role in consumer products. However, the increasing use of nanomaterials has raised concern over inadvertent exposure and potential risks for human health and the environment. Henceforth, in vivo testing of nanoparticles and protection against its toxicity is required. Using rat as an animal model, effect of sodium selenite (Se), an essential trace element, on rat testes exposed to silver nanoparticles (AgNPs) was evaluated. Male rats were treated with AgNPs (5 mg/kg/b.w) i/p or Se (0.2 mg/kg/b.w) by gavage. AgNP administration decreased Glutathione (GSH) levels and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) and increased levels of malondialdehyde (MDA) and expression of interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α). However, treatment with Se increased GSH levels and activities of SOD, CAT, and GPx compared with AgNP-treated group and decreased the level of MDA and inflammatory biomarkers significantly (p < 0.05) as compared with AgNP-treated group. Light microscopic analyses also revealed that AgNP induced histopathological changes in testes tissue. Further, protection by Se on biochemical results was confirmed by alleviation of the histopathological changes in the tissue. Results show the adverse effects of AgNPs on the male reproductive tract, particularly spermatogenesis, and suggest that Se possesses significant potential in reducing AgNP-induced testicular toxicity.
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Affiliation(s)
- Sabah Ansar
- Clinical Laboratory Sciences, Applied Medical Science, King Saud University, Riyadh, Saudi Arabia.
| | - Manal Abudawood
- Clinical Laboratory Sciences, Applied Medical Science, King Saud University, Riyadh, Saudi Arabia
| | - Sherifa Shaker Hamed
- Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia
- Zoology Department, Faculty of Science, University of Alexandria, Moharram Bey, Alexandria, Egypt
| | - Mukhtar M Aleem
- Chemistry and Biochemistry Department, University of California, Santa Cruz, CA, USA
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5
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França LR, Hess RA, Dufour JM, Hofmann MC, Griswold MD. The Sertoli cell: one hundred fifty years of beauty and plasticity. Andrology 2016; 4:189-212. [PMID: 26846984 DOI: 10.1111/andr.12165] [Citation(s) in RCA: 259] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/30/2015] [Accepted: 01/04/2016] [Indexed: 12/18/2022]
Abstract
It has been one and a half centuries since Enrico Sertoli published the seminal discovery of the testicular 'nurse cell', not only a key cell in the testis, but indeed one of the most amazing cells in the vertebrate body. In this review, we begin by examining the three phases of morphological research that have occurred in the study of Sertoli cells, because microscopic anatomy was essentially the only scientific discipline available for about the first 75 years after the discovery. Biochemistry and molecular biology then changed all of biological sciences, including our understanding of the functions of Sertoli cells. Immunology and stem cell biology were not even topics of science in 1865, but they have now become major issues in our appreciation of Sertoli cell's role in spermatogenesis. We end with the universal importance and plasticity of function by comparing Sertoli cells in fish, amphibians, and mammals. In these various classes of vertebrates, Sertoli cells have quite different modes of proliferation and epithelial maintenance, cystic vs. tubular formation, yet accomplish essentially the same function but in strikingly different ways.
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Affiliation(s)
- L R França
- Laboratory of Cellular Biology, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.,National Institute for Amazonian Research (INPA), Manaus, Amazonas, Brazil
| | - R A Hess
- Reproductive Biology and Toxicology, Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA
| | - J M Dufour
- Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - M C Hofmann
- Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - M D Griswold
- Center for Reproductive Biology, School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
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6
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Ansar S, AlGhosoon HT, Hamed S. Evaluation of protective effect of rutin on lead acetate-induced testicular toxicity in Wistar rats. TOXIN REV 2016. [DOI: 10.3109/15569543.2015.1136333] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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7
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Domke LM, Rickelt S, Dörflinger Y, Kuhn C, Winter-Simanowski S, Zimbelmann R, Rosin-Arbesfeld R, Heid H, Franke WW. The cell-cell junctions of mammalian testes: I. The adhering junctions of the seminiferous epithelium represent special differentiation structures. Cell Tissue Res 2014; 357:645-65. [PMID: 24907851 PMCID: PMC4148596 DOI: 10.1007/s00441-014-1906-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 04/28/2014] [Indexed: 01/08/2023]
Abstract
The seminiferous tubules and the excurrent ducts of the mammalian testis are physiologically separated from the mesenchymal tissues and the blood and lymph system by a special structural barrier to paracellular translocations of molecules and particles: the "blood-testis barrier", formed by junctions connecting Sertoli cells with each other and with spermatogonial cells. In combined biochemical as well as light and electron microscopical studies we systematically determine the molecules located in the adhering junctions of adult mammalian (human, bovine, porcine, murine, i.e., rat and mouse) testis. We show that the seminiferous epithelium does not contain desmosomes, or "desmosome-like" junctions, nor any of the desmosome-specific marker molecules and that the adhering junctions of tubules and ductules are fundamentally different. While the ductules contain classical epithelial cell layers with E-cadherin-based adherens junctions (AJs) and typical desmosomes, the Sertoli cells of the tubules lack desmosomes and "desmosome-like" junctions but are connected by morphologically different forms of AJs. These junctions are based on N-cadherin anchored in cytoplasmic plaques, which in some subforms appear thick and dense but in other subforms contain only scarce and loosely arranged plaque structures formed by α- and β-catenin, proteins p120, p0071 and plakoglobin, together with a member of the striatin family and also, in rodents, the proteins ZO-1 and myozap. These N-cadherin-based AJs also include two novel types of junctions: the "areae adhaerentes", i.e., variously-sized, often very large cell-cell contacts and small sieve-plate-like AJs perforated by cytoplasm-to-cytoplasm channels of 5-7 nm internal diameter ("cribelliform junctions"). We emphasize the unique character of this epithelium that totally lacks major epithelial marker molecules and structures such as keratin filaments and desmosomal elements as well as EpCAM- and PERP-containing junctions. We also discuss the nature, development and possible functions of these junctions.
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Affiliation(s)
- Lisa M. Domke
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Brandenburg University of Technology, Senftenberg, Germany
- Present Address: Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology (MIT), Cambridge, MA USA
| | - Steffen Rickelt
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Yvette Dörflinger
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Caecilia Kuhn
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Progen Biotechnik GmbH, Heidelberg, Germany
| | - Stefanie Winter-Simanowski
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Ralf Zimbelmann
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Rina Rosin-Arbesfeld
- Department of Anatomy, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Hans Heid
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Werner W. Franke
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Progen Biotechnik GmbH, Heidelberg, Germany
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Agbor VA, Tao S, Lei N, Heckert LL. A Wt1-Dmrt1 transgene restores DMRT1 to sertoli cells of Dmrt1(-/-) testes: a novel model of DMRT1-deficient germ cells. Biol Reprod 2013; 88:51. [PMID: 23255335 DOI: 10.1095/biolreprod.112.103135] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
DMRT1 is an evolutionarily conserved transcriptional factor expressed only in the postnatal testis, where it is produced in Sertoli cells and germ cells. While deletion of Dmrt1 in mice demonstrated it is required for postnatal testis development and fertility, much is still unknown about its temporal- and cell-specific functions. This study characterized a novel mouse model of DMRT1-deficient germ cells that was generated by breeding Dmrt1-null (Dmrt1(-/-)) mice with Wt1-Dmrt1 transgenic (Dmrt1(+/-;tg)) mice, which express a rat Dmrt1 cDNA in gonadal supporting cells by directing it from the Wilms tumor 1 locus in a yeast artificial chromosome transgene. Like Dmrt1(-/-) mice, male Dmrt1(-/-) transgenic mice (Dmrt1(-/-;tg)) were infertile, while female mice were fertile. Immunohistochemistry and Western blot analysis showed transgenic DMRT1 expressed in supporting cells of the newborn gonads of both sex and in Sertoli cells of the testis afterbirth. Sertoli cells were evaluated by electron microscopy, revealing that maturation of Dmrt1(-/-;tg) Sertoli cells was incomplete. Morphological analysis of testes from 42-day-old mice showed that, compared to Dmrt1(-/-) mice, Dmrt1(-/-;tg) mice have improved seminiferous tubule structure, with lumens present in many. Immunohistochemistry of the polarity markers ESPIN and NECTIN-2 showed that DMRT1 in Sertoli cells is required for NECTIN-2 expression and influences organization of ectoplasmic specializations. Further functional analyses of the transgene on a Dmrt1(-/-) background showed that it did not rescue the decrease in Dmrt1(-/-) testis size, but when expressed on a wild-type background, exogenous DMRT1 prevented the normal age-related decline in testis size and enhanced sperm progressive motility. The studies suggest that DMRT1 in Sertoli cells regulates tubule morphology, spermatogenesis, and sperm function via its effects on Sertoli cell maturation and polarity. Furthermore, expression and function of transgenic DMRT1 in Sertoli cells establishes a novel mouse model of DMRT1-deficient germ cells generated by breeding Dmrt1-null mice with Wt1-Dmrt1 transgenic mice (rescue; Dmrt1(-/-;tg)).
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Affiliation(s)
- Valentine A Agbor
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Xiao X, Mruk DD, Cheng CY. Intercellular adhesion molecules (ICAMs) and spermatogenesis. Hum Reprod Update 2013; 19:167-86. [PMID: 23287428 DOI: 10.1093/humupd/dms049] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND During the seminiferous epithelial cycle, restructuring takes places at the Sertoli-Sertoli and Sertoli-germ cell interface to accommodate spermatogonia/spermatogonial stem cell renewal via mitosis, cell cycle progression and meiosis, spermiogenesis and spermiation since developing germ cells, in particular spermatids, move 'up and down' the seminiferous epithelium. Furthermore, preleptotene spermatocytes differentiated from type B spermatogonia residing at the basal compartment must traverse the blood-testis barrier (BTB) to enter the adluminal compartment to prepare for meiosis at Stage VIII of the epithelial cycle, a process also accompanied by the release of sperm at spermiation. These cellular events that take place at the opposite ends of the epithelium are co-ordinated by a functional axis designated the apical ectoplasmic specialization (ES)-BTB-basement membrane. However, the regulatory molecules that co-ordinate cellular events in this axis are not known. METHODS Literature was searched at http://www.pubmed.org and http://scholar.google.com to identify published findings regarding intercellular adhesion molecules (ICAMs) and the regulation of this axis. RESULTS Members of the ICAM family, namely ICAM-1 and ICAM-2, and the biologically active soluble ICAM-1 (sICAM-1) are the likely regulatory molecules that co-ordinate these events. sICAM-1 and ICAM-1 have antagonistic effects on the Sertoli cell tight junction-permeability barrier, involved in Sertoli cell BTB restructuring, whereas ICAM-2 is restricted to the apical ES, regulating spermatid adhesion during the epithelial cycle. Studies in other epithelia/endothelia on the role of the ICAM family in regulating cell movement are discussed and this information has been evaluated and integrated into studies of these proteins in the testis to create a hypothetical model, depicting how ICAMs regulate junction restructuring events during spermatogenesis. CONCLUSIONS ICAMs are crucial regulatory molecules of spermatogenesis. The proposed hypothetical model serves as a framework in designing functional experiments for future studies.
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Affiliation(s)
- Xiang Xiao
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA
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10
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Irie K, Shimizu K, Sakisaka T, Ikeda W, Takai Y. Roles of nectins in cell adhesion, signaling and polarization. Handb Exp Pharmacol 2012:343-72. [PMID: 20455098 DOI: 10.1007/978-3-540-68170-0_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Nectins are Ca(2+)-independent immunoglobulin-like cell-cell adhesion molecules which constitute a family of four members. Nectins homophilically and heterophilically trans-interact and cause cell-cell adhesion. This nectin-based cell-cell adhesion plays roles in the organization of adherens junctions in epithelial cells and fibroblasts and synaptic junctions in neurons in cooperation with cadherins. The nectin-based cell-cell adhesion plays roles in the contacts between commissural axons and floor plate cells and in the organization of Sertoli cell-spermatid junctions in the testis, independently of cadherins. Nectins furthermore regulate intracellular signaling through Cdc42 and Rac small G proteins and cell polarization through cell polarity proteins. Pathologically, nectins serve as entry and cell-cell spread mediators of herpes simplex viruses.
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Affiliation(s)
- K Irie
- Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
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11
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Chung SSW, Choi C, Wang X, Hallock L, Wolgemuth DJ. Aberrant distribution of junctional complex components in retinoic acid receptor alpha-deficient mice. Microsc Res Tech 2010; 73:583-96. [PMID: 19937743 PMCID: PMC2877760 DOI: 10.1002/jemt.20797] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Retinoic acid receptor alpha (RARalpha)-deficient mice are sterile, with abnormalities in the progression of spermatogenesis and spermiogenesis. In this study, we investigated whether defective retinoid signaling involved at least in part, disrupted cell-cell interactions. Hypertonic fixation approaches revealed defects in the integrity of the Sertoli-cell barrier in the tubules of RARalpha-deficient testes. Dye transfer experiments further revealed that coupling between cells from the basal to adluminal compartments was aberrant. There were also differences in the expression of several known retinoic acid (RA)-responsive genes encoding structural components of tight junctions and gap junctions. Immunostaining demonstrated a delay in the incorporation of zonula occludens (ZO-1), a peripheral component protein of tight junctions, into the Sertoli cell tight junctions. Markedly reduced expression of connexin-40 in mutant pachytene spermatocytes and round spermatids was found by in situ hybridization. An ectopic distribution of vimentin and disrupted cyclic expression of vimentin, which is usually tightly regulated during spermiogenesis, was found in RARalpha-deficient testes at all ages examined. Thus, the specific defects in spermiogenesis in RARalpha-deficient testes may correlate with a disrupted cyclic expression of RA-responsive structural components, including vimentin, a downregulation of connexin-40 in spermatogenic cells, and delayed assembly of ZO-1 into Sertoli cell tight junctions. Interestingly, bioinformatic analysis revealed that many genes that are components of tight junctions and gap junctions contained potential retinoic acid response element binding sites.
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Affiliation(s)
- Sanny S W Chung
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032
- The Institute of Human Nutrition, Columbia University Medical Center, New York, NY 10032
| | - Cindy Choi
- The Institute of Human Nutrition, Columbia University Medical Center, New York, NY 10032
| | - Xiangyuan Wang
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
| | - Loretta Hallock
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
| | - Debra J Wolgemuth
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032
- The Institute of Human Nutrition, Columbia University Medical Center, New York, NY 10032
- The Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032
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12
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Hermo L, Pelletier RM, Cyr DG, Smith CE. Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 5: intercellular junctions and contacts between germs cells and Sertoli cells and their regulatory interactions, testicular cholesterol, and genes/proteins associated with more than one germ cell generation. Microsc Res Tech 2010; 73:409-94. [PMID: 19941291 DOI: 10.1002/jemt.20786] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In the testis, cell adhesion and junctional molecules permit specific interactions and intracellular communication between germ and Sertoli cells and apposed Sertoli cells. Among the many adhesion family of proteins, NCAM, nectin and nectin-like, catenins, and cadherens will be discussed, along with gap junctions between germ and Sertoli cells and the many members of the connexin family. The blood-testis barrier separates the haploid spermatids from blood borne elements. In the barrier, the intercellular junctions consist of many proteins such as occludin, tricellulin, and claudins. Changes in the expression of cell adhesion molecules are also an essential part of the mechanism that allows germ cells to move from the basal compartment of the seminiferous tubule to the adluminal compartment thus crossing the blood-testis barrier and well-defined proteins have been shown to assist in this process. Several structural components show interactions between germ cells to Sertoli cells such as the ectoplasmic specialization which are more closely related to Sertoli cells and tubulobulbar complexes that are processes of elongating spermatids embedded into Sertoli cells. Germ cells also modify several Sertoli functions and this also appears to be the case for residual bodies. Cholesterol plays a significant role during spermatogenesis and is essential for germ cell development. Lastly, we list genes/proteins that are expressed not only in any one specific generation of germ cells but across more than one generation.
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Affiliation(s)
- Louis Hermo
- Faculty of Medicine, Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada H3A 2B2.
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13
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Vogl AW, Vaid KS, Guttman JA. The Sertoli cell cytoskeleton. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 636:186-211. [PMID: 19856169 DOI: 10.1007/978-0-387-09597-4_11] [Citation(s) in RCA: 188] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The cytoskeleton of terminally differentiated mammalian Sertoli cells is one of the most elaborate of those that have been described for cells in tissues. Actin filaments, intermediate filaments and microtubules have distinct patterns of distribution that change during the cyclic process of spermatogenesis. Each of the three major cytoskeletal elements is either concentrated at or related in part to intercellular junctions. Actin filaments are concentrated in unique structures termed ectoplasmic specializations that function in intercellular adhesion, and at tubulobulbar complexes that are thought to be involved with junction internalization during sperm release and movement of spermatocytes through basal junctions between neighboring Sertoi cells. Intermediate filaments occur in a perinuclear network which has peripheral extensions to desmosome-like junctions with adjacent cells and to small hemidesmosome-like attachments to the basal lamina. Unlike in most other epithelia where the intermediate filaments are of the keratin type, intermediate filaments in mature Sertoli cells are of the vimentin type. The function of intermediate filaments in Sertoli cells in not entirely clear; however, the pattern of filament distribution and the limited experimental data available are consistent with a role in maintaining tissue integrity when the epithelium is mechanically stressed. Microtubules are abundant in Sertoli cells and are predominantly oriented parallel to the long axis of the cell. Microtubules are involved with maintaining the columnar shape of Sertoli cells, with transporting and positioning organelles in the cytoplasm, and with secreting seminiferous tubule fluid. In addition, microtubule-based transport machinery is coupled to intercellular junctions to translocate and position adjacent spermatids in the epithelium. Although the cytoskeleton of Sertoli cells has structural and functional properties common to cells generally, there are a number of properties that are unique and that appear related to processes fundamental to spermatogenesis and to interfacing somatic cells both with similar neighboring somatic cells and with differentiating cells of the germ cell line.
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Affiliation(s)
- A Wayne Vogl
- Department of Cellular and Physiological Sciences, The University of British Columbia, Vancouver, British Columbia, Canada.
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Thomas C, Tholl S, Moes D, Dieterle M, Papuga J, Moreau F, Steinmetz A. Actin bundling in plants. ACTA ACUST UNITED AC 2009; 66:940-57. [DOI: 10.1002/cm.20389] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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Cheng CY, Mruk DD. An intracellular trafficking pathway in the seminiferous epithelium regulating spermatogenesis: a biochemical and molecular perspective. Crit Rev Biochem Mol Biol 2009; 44:245-63. [PMID: 19622063 PMCID: PMC2758293 DOI: 10.1080/10409230903061207] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
During spermatogenesis in adult rat testes, fully developed spermatids (i.e. spermatozoa) at the luminal edge of the seminiferous epithelium undergo "spermiation" at stage VIII of the seminiferous epithelial cycle. This is manifested by the disruption of the apical ectoplasmic specialization (apical ES) so that spermatozoa can enter the tubule lumen and to complete their maturation in the epididymis. At the same time, the blood-testis barrier (BTB) located near the basement membrane undergoes extensive restructuring to allow transit of preleptotene spermatocytes so that post-meiotic germ cells complete their development behind the BTB. While spermiation and BTB restructuring take place concurrently at opposite ends of the Sertoli cell epithelium, the biochemical mechanism(s) by which they are coordinated were not known until recently. Studies have shown that fragments of laminin chains are generated from the laminin/integrin protein complex at the apical ES via the action of MMP-2 (matrix metalloprotease-2) at spermiation. These peptides serve as the local autocrine factors to destabilize the BTB. These laminin peptides also exert their effects on hemidesmosome which, in turn, further potentiates BTB restructuring. Thus, a novel apical ES-BTB-hemidesmosome regulatory loop is operating in the seminiferous epithelium to coordinate these two crucial cellular events of spermatogenesis. This functional loop is further assisted by the Par3/Par6-based polarity protein complex in coordination with cytokines and testosterone at the BTB. Herein, we provide a critical review based on the latest findings in the field regarding the regulation of these cellular events. These recent findings also open up a new window for investigators studying blood-tissue barriers.
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Affiliation(s)
- C Yan Cheng
- Center for Biomedical Research, Population Council, 1230 York Avenue, New York, New York 10065, USA.
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16
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Lee NPY, Wong EWP, Mruk DD, Cheng CY. Testicular cell junction: a novel target for male contraception. Curr Med Chem 2009; 16:906-15. [PMID: 19275601 DOI: 10.2174/092986709787549262] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Even though various contraceptive methods are widely available, the number of unwanted pregnancies is still on the rise in developing countries, pressurizing the already resource limited nations. One of the major underlying reasons is the lack of effective, low cost, and safe contraceptives for couples. During the past decade, some studies were performed using animal models to decipher if the Sertoli-germ cell junction in the testis is a target for male fertility regulation. Some of these study models were based on the use of hormones and/or chemicals to disrupt the hypothalamic-pituitary-testicular axis (e.g., androgen-based implants or pills) and others utilized a panel of chemical entities or synthetic peptides to perturb spermatogenesis either reversibly or non-reversibly. Among them, adjudin, a potential male contraceptive, is one of the compounds exerting its action on the unique adherens junctions, known as ectoplasmic specializations, in the testis. Since the testis is equipped with inter-connected cell junctions, an initial targeting of one junction type may affect the others and these accumulative effects could lead to spermatogenic arrest. This review attempts to cover an innovative theme on how male infertility can be achieved by inducing junction instability and defects in the testis, opening a new window of research for male contraceptive development. While it will still take much time and effort of intensive investigation before a product can reach the consumable market, these findings have provided hope for better family planning involving men.
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Affiliation(s)
- Nikki P Y Lee
- Center for Biomedical Research, Population Council, New York, New York 10065, USA.
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17
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Koduri S, Hild SA, Pessaint L, Reel JR, Attardi BJ. Mechanism of action of l-CDB-4022, a potential nonhormonal male contraceptive, in the seminiferous epithelium of the rat testis. Endocrinology 2008; 149:1850-60. [PMID: 18174280 PMCID: PMC2276710 DOI: 10.1210/en.2007-1332] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The present study was conducted to elucidate the possible molecular mechanisms involved in the antispermatogenic activity of l-CDB-4022, an indenopyridine. In this study 45-d-old male Sprague-Dawley rats were treated with a single oral dose of l-CDB-4022 (2.5 mg/kg) or vehicle, and blood and testes were collected at various time points. The rate of body weight gain was not affected, but a significant loss of testes weight was induced by l-CDB-4022. Serum hormones were assayed using specific RIAs or ELISAs, and testicular protein and RNA were analyzed by Western blotting and RT-PCR, respectively. There was a significant decrease in inhibin B and concomitant increase in FSH in serum from l-CDB-4022-treated rats, but serum levels of activin A, testosterone, and LH were unchanged. Western analysis of testicular lysates from l-CDB-4022-treated rats exhibited phosphorylation of ERK1/2 at 4 h and later time points. Loss of nectin/afadin complex occurred at 48 h, but there was an increase in levels of integrin-beta1, N-cadherin, alpha-catenin, and beta-catenin protein at 24 h and later time points. Increase in expression of Fas ligand and Fas receptor was detected 8 and 24 h after l-CDB-4022 treatment. The ratio of the membrane to soluble form of stem cell factor mRNA was decreased. Immunohistochemical analysis of testicular sections indicated a dramatic disruption of the Sertoli cell microtubule network in l-CDB-4022-treated rats. Collectively, these results suggest that l-CDB-4022 activates the MAPK pathway, reduces expression of prosurvival factors such as the membrane form of stem cell factor, alters expression of Sertoli-germ cell adherens junction proteins, disrupts Sertoli cell microtubule structure, and induces the proapoptotic factor, Fas, culminating in germ cell loss from the seminiferous epithelium.
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Affiliation(s)
- Sailaja Koduri
- Division of Reproductive Endocrinology and Toxicology, BIOQUAL Inc., 9600 Medical Center Drive, Rockville, MD 20850-3336, USA.
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18
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Mruk DD. New perspectives in non-hormonal male contraception. Trends Endocrinol Metab 2008; 19:57-64. [PMID: 18291665 DOI: 10.1016/j.tem.2007.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 11/03/2007] [Accepted: 11/05/2007] [Indexed: 02/06/2023]
Abstract
As the world's population continues to soar, contraception has become increasingly important. Recently, men have expressed willingness to share the burden of family planning. Thus, safe, effective and reversible male contraceptives would satisfy an urgent need among couples. Currently, there are several promising non-hormonal contraceptives at various stages of research and development. In addition, major advances in genomic and proteomic research have been instrumental in identifying and characterizing genes and proteins expressed uniquely in the testis or other male reproductive organs, which might become 'druggable' targets for non-hormonal male contraceptive development in the future. Through committed research, advocacy and support, male contraceptives are likely to become a valuable addition to the current choices of family planning.
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Affiliation(s)
- Dolores D Mruk
- Population Council, Center for Biomedical Research, 1230 York Avenue, New York, NY 10065, USA.
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19
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Wang F, Zhang Q, Cao J, Huang Q, Zhu X. The microtubule plus end-binding protein EB1 is involved in Sertoli cell plasticity in testicular seminiferous tubules. Exp Cell Res 2008; 314:213-26. [DOI: 10.1016/j.yexcr.2007.09.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 08/28/2007] [Accepted: 09/21/2007] [Indexed: 10/22/2022]
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20
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Anahara R, Toyama Y, Koda M, Honma S, Nishihira J, Toshimori K, Mori C. Deletion of macrophage migration inhibitory factor gene induces down regulation of sex hormones and ultrastructural abnormalities in mouse testes. Reprod Toxicol 2006; 21:167-70. [PMID: 16188421 DOI: 10.1016/j.reprotox.2005.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 08/14/2005] [Accepted: 08/19/2005] [Indexed: 11/27/2022]
Abstract
Macrophage migration inhibitory factor (MIF) is a multifunctional protein that acts as a pro-inflammatory cytokine, pituitary hormone, immunoregulator and mitogen. The MIF gene knockout (MIFKO) mouse has been used to study the MIF response in many tissues, such as with skin injury and spinal cord injury; however, there is little information about the MIFKO mouse testis. This study reports the levels of serum and intratesticular estradiol and testosterone, the ultrastructure of the testis, and preliminary findings from in vitro fertilization. Our results revealed a decrease in estradiol and testosterone levels and deformation in spermiogenesis, in the MIFKO mouse. These initial findings study may lead to a better understanding of the role that MIF plays in the mouse testis.
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Affiliation(s)
- Reiko Anahara
- Department of Bioenvironmental Medicine, Graduate School of Medicine, Chiba University, A3 1-8-1, Inohana, Chiba 260-8670, Japan
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21
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Zhang J, Mruk DD, Cheng CY. Myotubularin phosphoinositide phosphatases, protein phosphatases, and kinases: their roles in junction dynamics and spermatogenesis. J Cell Physiol 2005; 204:470-83. [PMID: 15690393 DOI: 10.1002/jcp.20303] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Spermatogenesis in the seminiferous epithelium of the mammalian testis is a dynamic cellular event. It involves extensive restructuring at the Sertoli-germ cell interface, permitting germ cells to traverse the epithelium from basal to adluminal compartment. As such, Sertoli-germ cell actin-based adherens junctions (AJ), such as ectoplasmic specializations (ES), must disassemble and reassemble to facilitate this event. Recent studies have shown that AJ dynamics are regulated by intricate interactions between AJ integral membrane proteins (e.g., cadherins, alpha6beta1 integrins and nectins), phosphatases, kinases, adaptors, and the underlying cytoskeleton network. For instance, the myotubularin (MTM) phosphoinositide (PI) phosphatases, such as MTM related protein 2 (MTMR2), can form a functional complex with c-Src (a non-receptor protein tyrosine kinase). In turn, this phosphatase/kinase complex associates with beta-catenin, a constituent of the N-cadherin/beta-catenin functional unit at the AJ site. This MTMR2-c-Src-beta-catenin complex apparently regulates the phosphorylation status of beta-catenin, which determines cell adhesive function conferred by the cadherin-catenin protein complex in the seminiferous epithelium. In this review, we discuss the current status of research on selected phosphatases and kinases, and how these proteins potentially interact with adaptors at AJ in the seminiferous epithelium to regulate cell adhesion in the testis. Specific research areas that are open for further investigation are also highlighted.
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Affiliation(s)
- Jiayi Zhang
- Population Council, Center for Biomedical Research, New York, New York, USA
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22
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Lee NPY, Mruk DD, Wong CH, Cheng CY. Regulation of Sertoli-germ cell adherens junction dynamics in the testis via the nitric oxide synthase (NOS)/cGMP/protein kinase G (PRKG)/beta-catenin (CATNB) signaling pathway: an in vitro and in vivo study. Biol Reprod 2005; 73:458-71. [PMID: 15858215 DOI: 10.1095/biolreprod.105.040766] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
During spermatogenesis, extensive restructuring of cell junctions takes place in the seminiferous epithelium to facilitate germ cell movement. However, the mechanism that regulates this event remains largely unknown. Recent studies have shown that nitric oxide (NO) likely regulates tight junction (TJ) dynamics in the testis via the cGMP/protein kinase G (cGMP-dependent protein kinase, PRKG) signaling pathway. Due to the proximity of TJ and adherens junctions (AJ) in the testis, in particular at the blood-testis barrier, it is of interest to investigate if NO can affect AJ dynamics. Studies using Sertoli-germ cell cocultures in vitro have shown that the levels of NOS (nitric oxide synthase), cGMP, and PRKG were induced when anchoring junctions were being established. Using an in vivo model in which adult rats were treated with adjudin [a molecule that induces adherens junction disruption, formerly called AF-2364, 1-(2,4-dichlorobenzyl)-IH-indazole-3-carbohydrazide], the event of AJ disruption was also associated with a transient iNOS (inducible nitric oxide synthase, NOS2) induction. Immunohistochemistry has illustrated that NOS2 was intensely accumulated in Sertoli and germ cells in the epithelium during adjudin-induced germ cell loss, with a concomitant accumulation of intracellular cGMP and an induction of PRKG but not cAMP or protein kinase A (cAMP-dependent protein kinase, PRKA). To identify the NOS-mediated downstream signaling partners, coimmunoprecipitation was used to demonstrate that NOS2 and eNOS (endothelial nitric oxide synthase, NOS3) were structurally associated with the N-cadherin (CDH2)/beta-catenin (CATNB)/actin complex but not the nectin-3 (poliovirus receptor-related 3, PVRL 3)/afadin (myeloid/lymphoid or mixed lineage-leukemia tranlocation to 4 homolog, MLLT4) nor the integrin beta1 (ITB1)-mediated protein complexes, illustrating the spatial vicinity of NOS with selected AJ-protein complexes. Interestingly, CDH2 and CATNB were shown to dissociate from NOS during the adjudin-mediated AJ disruption, implicating the CDH2/CATNB protein complex is the likely downstream target of the NO signaling. Furthermore, PRKG, the downstream signaling protein of NOS, was shown to interact with CATNB in the rat testis. Perhaps the most important of all, pretreatment of testes with KT5823, a specific PRKG inhibitor, can indeed delay the adjudin-induced germ cell loss, further validating NOS/NO regulates Sertoli-germ cell AJ dynamics via the cGMP/PRKG pathway. These results illustrate that the CDH2/CATNB-mediated adhesion function in the testis is regulated, at least in part, via the NOS/cGMP/PRKG/CATNB pathway.
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Yamada A, Irie K, Fukuhara A, Ooshio T, Takai Y. Requirement of the actin cytoskeleton for the association of nectins with other cell adhesion molecules at adherens and tight junctions in MDCK cells. Genes Cells 2004; 9:843-55. [PMID: 15330861 DOI: 10.1111/j.1365-2443.2004.00768.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Nectins, Ca(2+)-independent immunoglobulin-like cell adhesion molecules (CAMs), first form cell-cell adhesion where cadherins are recruited, forming adherens junctions (AJs) in epithelial cells and fibroblasts. In addition, nectins recruit claudins, occludin, and junctional adhesion molecules (JAMs) to the apical side of AJs, forming tight junctions (TJs) in epithelial cells. Nectins are associated with these CAMs through peripheral membrane proteins (PMPs), many of which are actin filament-binding proteins. We examined here the roles of the actin cytoskeleton in the association of nectins with other CAMs in MDCK cells stably expressing exogenous nectin-1. The nectin-1-based cell-cell adhesion was formed and maintained irrespective of the presence and absence of the actin filament-disrupting agents, such as cytochalasin D and latrunculin A. In the presence of these agents, only afadin remained at the nectin-1-based cell-cell adhesion sites, whereas E-cadherin and other PMPs at AJs, alpha-catenin, beta-catenin, vinculin, alpha-actinin, ADIP, and LMO7, were not concentrated there. The CAMs at TJs, claudin-1, occludin and JAM-1, or the PMPs at TJs, ZO-1 and MAGI-1, were not concentrated there, either. These results indicate that the actin cytoskeleton is required for the association of the nectin-afadin unit with other CAMs and PMPs at AJs and TJs.
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Affiliation(s)
- Akio Yamada
- Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita 565-0871, Japan
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24
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Mruk DD, Cheng CY. Sertoli-Sertoli and Sertoli-germ cell interactions and their significance in germ cell movement in the seminiferous epithelium during spermatogenesis. Endocr Rev 2004; 25:747-806. [PMID: 15466940 DOI: 10.1210/er.2003-0022] [Citation(s) in RCA: 596] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Spermatogenesis is the process by which a single spermatogonium develops into 256 spermatozoa, one of which will fertilize the ovum. Since the 1950s when the stages of the epithelial cycle were first described, reproductive biologists have been in pursuit of one question: How can a spermatogonium traverse the epithelium, while at the same time differentiating into elongate spermatids that remain attached to the Sertoli cell throughout their development? Although it was generally agreed upon that junction restructuring was involved, at that time the types of junctions present in the testis were not even discerned. Today, it is known that tight, anchoring, and gap junctions are found in the testis. The testis also has two unique anchoring junction types, the ectoplasmic specialization and tubulobulbar complex. However, attention has recently shifted on identifying the regulatory molecules that "open" and "close" junctions, because this information will be useful in elucidating the mechanism of germ cell movement. For instance, cytokines have been shown to induce Sertoli cell tight junction disassembly by shutting down the production of tight junction proteins. Other factors such as proteases, protease inhibitors, GTPases, kinases, and phosphatases also come into play. In this review, we focus on this cellular phenomenon, recapping recent developments in the field.
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Affiliation(s)
- Dolores D Mruk
- Population Council, Center for Biomedical Research, New York, New York 10021, USA.
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25
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Mueller S, Rosenquist TA, Takai Y, Bronson RA, Wimmer E. Loss of nectin-2 at Sertoli-spermatid junctions leads to male infertility and correlates with severe spermatozoan head and midpiece malformation, impaired binding to the zona pellucida, and oocyte penetration. Biol Reprod 2003; 69:1330-40. [PMID: 12801998 DOI: 10.1095/biolreprod.102.014670] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The members of the nectin/CD155 gene family represent a growing class of novel cell adhesion molecules of the immunoglobulin superfamily. In the present study, we describe the generation of a mouse line lacking a functional nectin-2 gene (nectin-2LacZ/LacZ) and analyze the resulting male-specific infertility phenotype. Although nectin-2LacZ/LacZ males produced normal amounts of motile spermatozoa, scanning electron microscopy revealed severe malformations of the spermatozoan head and midpiece. Besides a 4-fold reduction in migration of nectin-2LacZ/LacZ spermatozoa to the oviducts, in vitro binding to zona-intact mouse oocytes was reduced 6-fold. On the other hand, nectin-2LacZ/LacZ spermatozoa bound to zona-free hamster oocytes at near-wild type levels but, remarkably, failed to penetrate. In addition to the previously reported expression of nectin-2 and nectin-3 at Sertoli-spermatid junctions and of nectin-2 at inter-Sertoli cell junctions, we also found nectin-2 to localize at apical cell-cell junctions of the epididymal epithelium. Expression analysis of a LacZ knockin gene into the defunct nectin-2 gene in nectin-2LacZ/LacZ mice provided additional support for our earlier conjecture that in normal testis, nectin-2 is produced exclusively by Sertoli cells. Finally, we found Sertoli-spermatid junctions in nectin-2LacZ/LacZ mice to be virtually devoid of the actin-bundling protein espin, suggesting that ectoplasmic specializations fail to form in the absence of nectin-2. Our functional analyses indicate that the infertility phenotype of nectin-2-deficient male mice is caused by a combination of reduced migration to the oviduct, spermatozoa-zona binding, and sperm-oocyte fusion. We corroborate our previous description of a heterotypic adhesion complex between Sertoli cells and elongated spermatids that is maintained by nectin-2 and nectin-3, respectively.
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Affiliation(s)
- Steffen Mueller
- Department of Molecular Genetics, State University of New York at Stony Brook, New York 11794, USA
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Beardsley A, O'Donnell L. Characterization of normal spermiation and spermiation failure induced by hormone suppression in adult rats. Biol Reprod 2003; 68:1299-307. [PMID: 12606480 DOI: 10.1095/biolreprod.102.009811] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
At the end of spermatogenesis, elongated spermatids are released from supporting Sertoli cells via the process termed spermiation. Previous studies have shown that spermiation failure occurs after hormone suppression, in which spermatids are retained instead of releasing. However, the molecular mechanisms involved in spermiation and spermiation failure are largely unknown. The aims of the present study were, first, to characterize the ultrastructural events associated with normal spermiation and spermiation failure using light and electron microscopy and, second, to investigate the localization of cell adhesion-associated (beta1-integrin and cadherins) and junction-associated molecules (integrin-associated kinase [ILK], beta-catenin, and espin) during these processes. Four adult Sprague-Dawley rats received testosterone and estradiol implants and FSH antibody (2 mg kg-1 day-1) for 7 days to suppress testicular testosterone and FSH and to induce spermiation failure. Four rats treated with saline were used as controls. After testosterone and FSH suppression, spermiation at the ultrastructural level appeared to be normal until the final disengagement of the spermatids from Sertoli cells (stage VIII), at which stage a large number of retained spermatids were noted. Immunohistochemical localization of espin showed that during spermiation, removal of the ectoplasmic specialization (ES) occurred 30 h before spermatid disengagement, suggesting that non-ES junctions mediate the spermatid-Sertoli cell interaction before and during disengagement. beta1-Integrin and beta-catenin remained associated with spermatids after ES removal and until disengagement; however, ILK was removed along with the ES. Though detectable, N-cadherin was not associated with the spermatid-Sertoli cell junction. After testosterone and FSH suppression, beta1-integrin, but not N-cadherin or beta-catenin, remained associated with spermatids that failed to spermiate. In conclusion, hormone suppression-induced spermiation failure is caused by defects in the disengagement of spermatids from the Sertoli cell, and this process likely is mediated by beta1-integrin in an ILK-independent mechanism.
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Affiliation(s)
- Amanda Beardsley
- Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia
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Toyama Y, Maekawa M, Yuasa S. Ectoplasmic specializations in the Sertoli cell: new vistas based on genetic defects and testicular toxicology. Anat Sci Int 2003; 78:1-16. [PMID: 12680465 DOI: 10.1046/j.0022-7722.2003.00034.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract The ectoplasmic specialization is a unique junctional complex formed in two cortical areas of the Sertoli cell in the mammalian testis: one near the base of the seminiferous epithelium forming the blood-testis barrier, and the other near the lumen of the seminiferous tubule embracing the acrosome region of the developing spermatids. The specialization consists of the Sertoli cell plasma membrane, a subsurface cistern of the endoplasmic reticulum and a layer of closely packed actin filaments that is sandwiched between the plasma membrane and the subsurface cistern. No functions of the specializations other than the blood-testis barrier have been established. However, over the past decade, knowledge about the ectoplasmic specialization has been steadily accumulating and, in particular, there has been a tremendous increase in knowledge based on molecular biological approaches to specialization-associated proteins, including tight junction-associated proteins, based on phenotype analyses of gene-knockout mice and mutant animals, and based on analyses of the effects of exogenous estrogens, so-called endocrine disruptors. Progress in studies on the ectoplasmic specialization will facilitate the elucidation of numerous important questions regarding spermatogenesis, including the pathogenesis of azoospermia and the mechanisms of action of endocrine disruptors.
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Affiliation(s)
- Yoshiro Toyama
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Chiba University, Chiba, Japan.
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Lee NPY, Mruk D, Lee WM, Cheng CY. Is the cadherin/catenin complex a functional unit of cell-cell actin-based adherens junctions in the rat testis? Biol Reprod 2003; 68:489-508. [PMID: 12533412 DOI: 10.1095/biolreprod.102.005793] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Much controversy exists regarding the presence of the cadherin/catenin complex and its intracellular attachment site in the testis, which is the functional unit for actin-based cell-cell adherens junctions (AJs) in multiple epithelia. Furthermore, whether germ and Sertoli cells are equipped with the necessary AJ-associated signaling molecules to regulate this cadherin/catenin complex during spermatogenesis is not known. In the present study, it was shown that both Sertoli and germ cells indeed express N-cadherin, E-cadherin, alpha-catenin, beta-catenin, and p120(ctn) by semiquantitative reverse transcription-polymerase chain reaction and immunoblotting. Furthermore, the assembly of AJs between Sertoli and germ cells was associated with a transient induction in the steady-state mRNA and protein levels of cadherins and catenins. These analyses reveal, to our knowledge for the first time, that the testis may indeed be using the cadherin/catenin complex as one of the functional units to regulate AJ dynamics between Sertoli and germ cells in addition to alpha(6)beta(1) integrin and the nectin/afadin complex. To further confirm the existence of such a complex between Sertoli and germ cells, immunoprecipitation experiments were performed using Sertoli-germ cell lysates during AJ assembly. An anti-N-cadherin antibody can pull out beta-catenin, whereas N-cadherin can also be pulled out using an anti-beta-catenin antibody. To further expand and validate these in vitro biochemical studies, immunofluorescent histochemistry was performed, which colocalized N-cadherin and beta-catenin to the same site of Sertoli-Sertoli and Sertoli-germ cell AJs, possibly ectoplasmic specializations near the basal compartment, at the lower third of the seminiferous epithelium in vivo as well as between Sertoli cells cultured in vitro. Furthermore, studies by cross-linking using dithiobis(succinimidylpropionate) confirmed that the cadherin/catenin complex between Sertoli cells as well as between Sertoli and germ cells indeed structurally linked to actin but not to vimentin (an intermediate filament protein) or to tubulin (a microtubule protein). These results thus unequivocally demonstrate that the cadherin/catenin complex, which can be up-regulated by testosterone, is indeed present between Sertoli and germ cells and is used for the assembly of functional AJs.
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Affiliation(s)
- Nikki P Y Lee
- Population Council, Center for Biomedical Research, New York, New York 10021, USA
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Abstract
With the background that the foodborne mycotoxin aflatoxin B(1) (AFB(1)) could be toxic to the male reproductive mechanism in man as well as wild and domestic animals, the present study was aimed at finding the effect of AFB(1) on sperm. The Swiss albino mouse was the test animal. AFB(1,) suspended in corn oil and ethanol (95:5, v/v), was administered intraperitoneally to 90-day-old mice at a daily dose of 50 microg/kg body weight for 7, 15, 35 and 45 days. The analysis consisted of fertility testing and counts, motility and abnormalities of the cauda epididymidal sperm, adopting light- as well as electron-microscopy. The fertility of the treated mice was reduced drastically. Sperm concentration in the epididymis and sperm motility decreased whereas sperm abnormalities increased. In particular, sperm abnormalities like two axonemes in a common cytoplasm, sticking together of heads/tails, etc., were noted. A higher percentage of cauda epididymidal spermatozoa than in the control mice retained the cytoplasmic droplet (CD) and such retention was dependent on the duration of the treatment. Spermatozoa retaining the CD were inhibited in motility. Sperm CD of AFB(1)-treated mice contained electron-dense spherical inclusions, which are hypothesized as lipid inclusions produced from the lamellae through the spherical vesicles of the CD. The results indicate disruption of the spermatogenic as well as androgenic compartments of the testis by AFB(1). The results also reflect an alteration of epididymal function towards the post-testicular sperm maturation process by AFB(1).
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Affiliation(s)
- V F Agnes
- Department of Animal Science, School of Life Sciences, Bharathidhasan University, Tiruchirappalli-620024, India
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Nakai M, Miller MG, Carnes K, Hess RA. Stage-specific effects of the fungicide carbendazim on Sertoli cell microtubules in rat testis. Tissue Cell 2002; 34:73-80. [PMID: 12165241 DOI: 10.1016/s0040-8166(02)00006-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of the present study is to provide a morphological explanation of carbendazim (CBZ)-induced sloughing of germ cells that occurs in a stage-specific manner. Therefore, very early alterations in the seminiferous tubule epithelium were examined histologically in the rat testis after oral administration of CBZ (400mg/kg). Gaps between the elongated and round spermatids, the first indication of germ cell sloughing (pre-sloughing), were observed in stage late VI-early VII seminiferous tubules at 90-min post-treatment. Tubulin immunoreaction in the Sertoli cells was reduced in intensity in tubules with pre-sloughing. However, electron microscopy demonstrated that there were some intact microtubules in these cells. At 120 min, sloughing was seen in stage late VI-early VII and XIII-XIV. Tubulin immunoreaction in the Sertoli cells was greatly decreased in intensity in tubules where cell sloughing was observed. Electron microscopy showed that there were few microtubules in the body region of these cells. Stages II-V and mid-VII-VIII were exempt from the sloughing effect at 180 min. These changes in microtubules were not observed in Sertoli cells that did not exhibit sloughing characteristics, regardless of the post-treatment intervals. The present results suggest that stage specificity of sloughing is due to the stage-specific susceptibility of Sertoli cell microtubules to CBZ.
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Affiliation(s)
- M Nakai
- Department of Veterinary Biosciences, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL 61801, USA
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31
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Cheng CY, Mruk DD. Cell Junction Dynamics in the Testis: Sertoli-Germ Cell Interactions and Male Contraceptive Development. Physiol Rev 2002; 82:825-74. [PMID: 12270945 DOI: 10.1152/physrev.00009.2002] [Citation(s) in RCA: 420] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Spermatogenesis is an intriguing but complicated biological process. However, many studies since the 1960s have focused either on the hormonal events of the hypothalamus-pituitary-testicular axis or morphological events that take place in the seminiferous epithelium. Recent advances in biochemistry, cell biology, and molecular biology have shifted attention to understanding some of the key events that regulate spermatogenesis, such as germ cell apoptosis, cell cycle regulation, Sertoli-germ cell communication, and junction dynamics. In this review, we discuss the physiology and biology of junction dynamics in the testis, in particular how these events affect interactions of Sertoli and germ cells in the seminiferous epithelium behind the blood-testis barrier. We also discuss how these events regulate the opening and closing of the blood-testis barrier to permit the timely passage of preleptotene and leptotene spermatocytes across the blood-testis barrier. This is physiologically important since developing germ cells must translocate across the blood-testis barrier as well as traverse the seminiferous epithelium during their development. We also discuss several available in vitro and in vivo models that can be used to study Sertoli-germ cell anchoring junctions and Sertoli-Sertoli tight junctions. An in-depth survey in this subject has also identified several potential targets to be tackled to perturb spermatogenesis, which will likely lead to the development of novel male contraceptives.
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Affiliation(s)
- C Yan Cheng
- Population Council, Center for Biomedical Research, New York, New York 10021, USA.
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Maekawa M, Toyama Y, Yasuda M, Yagi T, Yuasa S. Fyn tyrosine kinase in Sertoli cells is involved in mouse spermatogenesis. Biol Reprod 2002; 66:211-21. [PMID: 11751285 DOI: 10.1095/biolreprod66.1.211] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Fyn is a member of the Src family of non-receptor-type tyrosine kinases and plays an important role in signal transductions regulating cell proliferation and differentiation. Fyn immunoreactivity was localized in the Sertoli cells of mouse testes. Although fyn-deficient adult male mice were fertile, a significant reduction in testis weight and degenerated germ cells were observed at 3 and 4 wk of age. Electron microscopic examination revealed that fyn -/- testis has ultrastructural abnormalities in the specialized junctional structures of the Sertoli cells, the ectoplasmic specializations. Unusual vesicular structures were found in the actin filament layers of the ectoplasmic specializations of mutant mice. Immunohistochemical studies demonstrated that both Fyn and actin filaments were concentrated in the areas of ectoplasmic specializations. At these sites, a high level of phosphotyrosine was also immunostained in wild-type testes, whereas phosphotyrosine immunoreactivity was reduced in fyn -/- testes. Immunoblot analyses revealed that Fyn was mainly distributed within the Triton X-100-insoluble cytoskeletal fraction prepared from wild-type testes, suggesting that Fyn might be associated with cytoskeletal proteins such as actin filaments. These findings suggest that Fyn kinase functions at the ectoplasmic specializations of the Sertoli cells in the testes, regulating the dynamics of cytoskeletal proteins. Fyn-mediated signal transduction in the Sertoli cells may affect the survival and differentiation of germ cells at a specific stage during spermatogenesis.
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Affiliation(s)
- Mamiko Maekawa
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan.
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Grieshaber SS, Lankenau DH, Talbot T, Holland S, Petersen NS. Expression of the 53 kD forked protein rescues F-actin bundle formation and mutant bristle phenotypes in Drosophila. CELL MOTILITY AND THE CYTOSKELETON 2001; 50:198-206. [PMID: 11807940 DOI: 10.1002/cm.10007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
forked mutations affect bristle development in Drosophila pupae, resulting in short, thick, gnarled bristles in the adult. The forked proteins are components of 200-300-microm-long actin fiber bundles that are present transiently during pupal development [Petersen et al., 1994: Genetics 136:173-182]. These bundles are composed of segments of 3-10 microm long, and forked protein is localized along the actin fiber bundle segments and accumulates at the junctions connecting them longitudinally. In the forked mutants, f(36a) and f(hd), F-actin bundles are greatly reduced in number and size, and bundle segmentation is absent. The p-element, P[w(+), falter] contains a 5.3-kb fragment of the forked gene that encodes the 53-kD forked protein [Lankenau et al., 1996: Mol Cell Biol 16:3535-3544]. Expression of only the 53-kD forked protein is sufficient to rescue the actin bundle and bristle phenotypes of f(36a) and f(hd) mutant flies. The 5.3-kb forked sequence, although smaller than the 13-kb region previously shown to rescue forked mutants [Petersen et al., 1994: Genetics 136:173-182], does contain the core forked sequence that encodes actin binding and bundling domains in cultured mammalian cells [Grieshaber and Petersen, 1999: J Cell Sci 112:2203-2211]. These data show that the 53-kD forked protein is sufficient for normal bristle development and that the domains shown previously to be important for actin bundling in cell culture may be all that are required for normal actin bundle formation in developing Drosophila bristles.
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Affiliation(s)
- S S Grieshaber
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, USA
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Mulholland DJ, Dedhar S, Vogl AW. Rat seminiferous epithelium contains a unique junction (Ectoplasmic specialization) with signaling properties both of cell/cell and cell/matrix junctions. Biol Reprod 2001; 64:396-407. [PMID: 11133699 DOI: 10.1095/biolreprod64.1.396] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The seminiferous epithelium contains unique actin related cell-cell junctions, termed ectoplasmic specializations (ESs). Turnover of these junctions is fundamental to sperm release and to movement of spermatocytes from basal to adluminal compartments of the epithelium during spermatogenesis. In this study we report several novel observations related to the spatial and temporal distribution of integrin-related signaling molecules at ESs. We confirm the presence of beta(1)-integrin at these sites and further demonstrate co-localization of integrin linked kinase (ILK). beta(1)-Integrin and ILK were shown by immunoprecipitation to associate in whole cell lysates of seminiferous epithelium. This observation provides the first evidence for a direct beta(1)-integrin/ILK interaction in noncultured epithelium. Pan-cadherin and beta-catenin antibodies did not react at ESs. Rather, antibodies reacted with desmosome-like junctions that are present both at basal junctional complexes between Sertoli cells and at sites of attachment to spermatogenic cells. Focal adhesion kinase (FAK), a known integrin-associated molecule, did not codistribute with beta(1)-integrins and did not associate with these adhesion molecules in immunoprecipitation studies. Although FAK was expressed in the epithelium, it appeared to be limited to the cytoplasm of early spermatogenic cells. Significantly, polyclonal antibodies against phosphotyrosine-containing residues reacted strongly at ESs, with highest levels detected during sperm release and turnover of basal junction complexes. Our observations indicate that ESs share cell signaling features both of cell-cell junctions and of cell-extracellular matrix junctions.
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Affiliation(s)
- D J Mulholland
- Department of Anatomy, University of British Columbia, Vancouver, British Columbia, Canada.
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O'Donnell L, Stanton PG, Bartles JR, Robertson DM. Sertoli cell ectoplasmic specializations in the seminiferous epithelium of the testosterone-suppressed adult rat. Biol Reprod 2000; 63:99-108. [PMID: 10859247 DOI: 10.1095/biolreprod63.1.99] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Sertoli cell ectoplasmic specialization is a unique junctional structure involved in the interaction between elongating spermatids and Sertoli cells. We have previously shown that suppression of testicular testosterone in adult rats by low-dose testosterone and estradiol (TE) treatment causes the premature detachment of step 8 round spermatids from the Sertoli cell. Because these detaching round spermatids would normally associate with the Sertoli cell via the ectoplasmic specialization, we hypothesized that ectoplasmic specializations would be absent in the seminiferous epithelium of TE-treated rats, and the lack of this junction would cause round spermatids to detach. In this study, we investigated Sertoli cell ectoplasmic specializations in normal and TE-treated rat testis using electron microscopy and localization of known ectoplasmic specialization-associated proteins (espin, actin, and vinculin) by immunocytochemistry and confocal microscopy. In TE-treated rats where round spermatid detachment was occurring, ectoplasmic specializations of normal morphology were observed opposite the remaining step 8 spermatids in the epithelium and, importantly, in the adluminal Sertoli cell cytoplasm during and after round spermatid detachment. When higher doses of testosterone were administered to promote the reattachment of all step 8 round spermatids, newly elongating spermatids associated with ectoplasmic specialization proteins within 2 days. We concluded that the Sertoli cell ectoplasmic specialization structure is qualitatively normal in TE-treated rats, and thus the absence of this structure is unlikely to be the cause of round spermatid detachment. We suggest that defects in adhesion molecules between round spermatids and Sertoli cells are likely to be involved in the testosterone-dependent detachment of round spermatids from the seminiferous epithelium.
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Affiliation(s)
- L O'Donnell
- Prince Henry's Institute of Medical Research, Monash Medical Centre, Clayton, Victoria 3168, Australia.
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Vogl AW. Spatially dynamic intercellular adhesion junction is coupled to a microtubule-based motility system: evidence from an in vitro binding assay. CELL MOTILITY AND THE CYTOSKELETON 2000; 34:1-12. [PMID: 9162577 DOI: 10.1002/(sici)1097-0169(1996)34:1<1::aid-cm1>3.0.co;2-g] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
During spermatogenesis, spermatids change position in the seminiferous epithelium along an axis that is perpendicular to the seminiferous tubule wall. During this period, spermatids are attached to apical invaginations of Sertoli cells. In areas of this attachment, unique junction plaques occur in Sertoli cells. These plaques consist of regions of the plasma membrane involved with intercellular adhesion, a layer of actin filaments that are hexagonally packed, and an underlying cistern of endoplasmic reticulum (ER). It previously has been proposed that these junction plaques, and therefore the attached spermatids, are translocated, by motor proteins, along microtubule tracts in the Sertoli cell. If this is true, microtubules should bind to the junction plaque in a nucleotide dependent fashion. To verify this prediction, seminiferous epithelia of the rat were separated from tubule walls and then mechanically fragmented. These epithelial preparations were incubated, in both the presence and absence of 10 mM Mg(+)(+)ATP, with exogenous microtubules stabilized with taxol. Then unbound microtubules were separated from microtubules bound to larger epithelial components by centrifuging the samples through a step sucrose gradient. The fraction enriched for elongate spermatids was collected and processed for electron microscopy. The results indicate that the junction plaques remain attached to spermatids, the plaques are intact, and the cytoplasmic face of the ER binds microtubules in a nucleotide dependent fashion. The results are consistent with the presence of motor proteins on the ER component of the junction plaques and with the general hypothesis of microtubule-dependent spermatid translocation.
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Affiliation(s)
- A W Vogl
- Department of Anatomy, University of British Columbia, Vancouver, Canada
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Wolfrum U, Liu X, Schmitt A, Udovichenko IP, Williams DS. Myosin VIIa as a common component of cilia and microvilli. CELL MOTILITY AND THE CYTOSKELETON 2000; 40:261-71. [PMID: 9678669 DOI: 10.1002/(sici)1097-0169(1998)40:3<261::aid-cm5>3.0.co;2-g] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The distribution of myosin VIIa, which is defective or absent in Usher syndrome 1B, was studied in a variety of tissues by immunomicroscopy. The primary aim was to determine whether this putative actin-based mechanoenzyme is a common component of cilia. Previously, it has been proposed that defective ciliary function might be the basis of some forms of Usher syndrome. Myosin VIIa was detected in cilia from cochlear hair cells, olfactory neurons, kidney distal tubules, and lung bronchi. It was also found to cofractionate with the axonemal fraction of retinal photoreceptor cells. Immunolabeling appeared most concentrated in the periphery of the transition zone of the cilia. This general presence of a myosin in cilia is surprising, given that cilia are dominated by microtubules, and not actin filaments. In addition to cilia, myosin VIIa was also found in actin-rich microvilli of different types of cell. We conclude that myosin VIIa is a common component of cilia and microvilli.
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Affiliation(s)
- U Wolfrum
- Zoologisches Institut, Universität Karlsruhe, Germany
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Vogl AW, Pfeiffer DC, Mulholland D, Kimel G, Guttman J. Unique and multifunctional adhesion junctions in the testis: ectoplasmic specializations. ARCHIVES OF HISTOLOGY AND CYTOLOGY 2000; 63:1-15. [PMID: 10770585 DOI: 10.1679/aohc.63.1] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this paper, we review the structure and function of a unique type of actin-related intercellular adhesion junctions in the testis. Based on their ultrastructure, the junctions are divided into five distinct domains. The currently identified molecular components of each domain are summarized. In addition, the architecture of the mammalian system is compared with that of non-mammalian vertebrates. Functionally, the junctions are related to the turnover of adhesion between Sertoli cells, to the attachment of spermatids to the seminiferous epithelium, and to sperm release. They also are part of the mechanism by which spermatids are moved through the epithelium. Evidence consistent with adhesion and motility related functions is discussed. Control, both of junction turnover and of microtubule-based transport, is identified as an important avenue for future research.
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Affiliation(s)
- A W Vogl
- Department of Anatomy, Faculty of Medicine, The University of British Columbia, Vancouver, Canada.
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Abstract
Parallel actin bundles are present in a diverse array of structures, where they are critical determinants of cellular shape and physiology. In the past 18 months, new findings have solidified the concept that parallel actin bundles are assembled in cells through the sequential action of multiple actin-bundling proteins and have begun to shed light on the roles played by the individual actin-bundling proteins.
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Affiliation(s)
- J R Bartles
- Department of Cell and Molecular Biology, Ward 11-185, Northwestern University Medical School, Chicago, IL 60611, USA.
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40
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Chen B, Li A, Wang D, Wang M, Zheng L, Bartles JR. Espin contains an additional actin-binding site in its N terminus and is a major actin-bundling protein of the Sertoli cell-spermatid ectoplasmic specialization junctional plaque. Mol Biol Cell 1999; 10:4327-39. [PMID: 10588661 PMCID: PMC25761 DOI: 10.1091/mbc.10.12.4327] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The espins are actin-binding and -bundling proteins localized to parallel actin bundles. The 837-amino-acid "espin" of Sertoli cell-spermatid junctions (ectoplasmic specializations) and the 253-amino-acid "small espin" of brush border microvilli are splice isoforms that share a C-terminal 116-amino-acid actin-bundling module but contain different N termini. To investigate the roles of espin and its extended N terminus, we examined the actin-binding and -bundling properties of espin constructs and the stoichiometry and developmental accumulation of espin within the ectoplasmic specialization. An espin construct bound to F-actin with an approximately threefold higher affinity (K(d) = approximately 70 nM) than small espin and was approximately 2.5 times more efficient at forming bundles. The increased affinity appeared to be due to an additional actin-binding site in the N terminus of espin. This additional actin-binding site bound to F-actin with a K(d) of approximately 1 microM, decorated actin stress fiber-like structures in transfected cells, and was mapped to a peptide between the two proline-rich peptides in the N terminus of espin. Espin was detected at approximately 4-5 x 10(6) copies per ectoplasmic specialization, or approximately 1 espin per 20 actin monomers and accumulated there coincident with the formation of parallel actin bundles during spermiogenesis. These results suggest that espin is a major actin-bundling protein of the Sertoli cell-spermatid ectoplasmic specialization.
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Affiliation(s)
- B Chen
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
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41
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Pineau C, Dupaix A, Jégou B. The Co-culture of Sertoli Cells and Germ Cells: Applications in Toxicology. Toxicol In Vitro 1999; 13:513-20. [DOI: 10.1016/s0887-2333(99)00025-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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42
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Beach SF, Vogl AW. Spermatid translocation in the rat seminiferous epithelium: coupling membrane trafficking machinery to a junction plaque. Biol Reprod 1999; 60:1036-46. [PMID: 10084982 DOI: 10.1095/biolreprod60.4.1036] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In this study, we demonstrate that specialized junction plaques that occur between Sertoli cells and spermatids in the rat testis support microtubule translocation in vitro. During spermatogenesis, Sertoli cells are attached to spermatids by specialized adhesion junctions termed ectoplasmic specializations (ESs). These structures consist of regions of the plasma membrane adherent to the spermatid head, a submembrane layer of tightly packed actin filaments, and an attached cistern of endoplasmic reticulum. It has been proposed that motor proteins on the endoplasmic reticulum interact with adjacent microtubules to translocate the junction plaques, and hence the attached spermatids, within the epithelium. If this hypothesis is true, then isolated junctions should support microtubule transport. To verify this prediction, we have mechanically isolated rat spermatids, together with their attached ESs, and tested them for their ability to transport microtubules in vitro. Most assays were done in the presence of 2 mg/ml testicular cytosol and at room temperature. ESs attached to spermatids supported microtubule translocation. In some cases in which motility events were detected, microtubules moved smoothly over the junction site. In others, the movement was slow but progressive, saltatory and "inch-worm-like." No motility was detected in the absence of exogenous ATP or in the presence of apyrase (an enzyme that catalyses the breakdown of ATP). Our results are consistent with the microtubule-based motility hypothesis of spermatid translocation.
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Affiliation(s)
- S F Beach
- Department of Anatomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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43
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Miller MG, Mulholland DJ, Vogl AW. Rat testis motor proteins associated with spermatid translocation (dynein) and spermatid flagella (kinesin-II). Biol Reprod 1999; 60:1047-56. [PMID: 10084983 DOI: 10.1095/biolreprod60.4.1047] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In this study, we report sites in the seminiferous epithelium of the rat testis that are immunoreactive with antibodies to the intermediate chain of cytoplasmic dynein and kinesin II. The study was done to determine whether or not microtubule-dependent motor proteins are present in Sertoli cell regions involved with spermatid translocation. Sections and epithelial fragments of perfusion-fixed rat testis were probed with an antibody (clone 74.1) to the intermediate chain of cytoplasmic dynein (IC74) and to kinesin-II. Labeling with the antibody to cytoplasmic dynein was dramatically evident in Sertoli cell regions surrounding apical crypts containing attached spermatids and known to contain unique intercellular attachment plaques. The antibody to kinesin II reacted only with spermatid tails. The levels of cytoplasmic dynein visible on immunoblots of supernatants collected from spermatid/junction complexes treated with an actin-severing enzyme (gelsolin) were greater than those of controls, indicating that at least some of the dynein may have been associated with Sertoli cell junction plaques attached to spermatids. Results are consistent with the conclusion that an isoform of cytoplasmic dynein may be responsible for the apical translocation of elongate spermatids that occurs before sperm release. Also, this is the first report of kinesin-II in mammalian spermatid tails.
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Affiliation(s)
- M G Miller
- Department of Environmental Toxicology, University of California, Davis, California 95616, USA
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Weil S, Degen AA, Rosenstrauch A, Friedländer M. Intratesticular spermatozoa retention in low fertility ageing roosters is related to malformations of Sertoli cell ectoplasmic specializations. ACTA ACUST UNITED AC 1996. [DOI: 10.1002/(sici)1097-010x(19960701)275:4<317::aid-jez10>3.0.co;2-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Bartles JR, Wierda A, Zheng L. Identification and characterization of espin, an actin-binding protein localized to the F-actin-rich junctional plaques of Sertoli cell ectoplasmic specializations. J Cell Sci 1996; 109 ( Pt 6):1229-39. [PMID: 8799813 DOI: 10.1242/jcs.109.6.1229] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ectoplasmic specializations are membrane-cytoskeletal assemblages found in Sertoli cells at sites of attachment to elongate spermatids or neighboring Sertoli cells. They are characterized in part by the presence of a unique junctional plaque which contains a narrow layer of parallel actin bundles sandwiched between the Sertoli cell plasma membrane and an affiliated cistern of endoplasmic reticulum. Using a monoclonal antibody, we have identified ‘espin,’ a novel actin-binding protein localized to ectoplasmic specializations. By immunogold electron microscopy, espin was localized to the parallel actin bundles of ectoplasmic specializations at sites where Sertoli cells contacted the heads of elongate spermatids. The protein was also detected at the sites of ectoplasmic specializations between neighboring Sertoli cells. Espin exhibits an apparent molecular mass of approximately 110 kDa in SDS gels. It is encoded by an approximately 2.9 kb mRNA, which was found to be specific to testis among the 11 rat organs and tissues examined. On the basis of cDNA sequence, espin is predicted to be an 836 amino acid protein which contains 8 ankyrin-like repeats in its N-terminal third, a potential P-loop, two proline-rich peptides and two peptides which contain clusters of multiple glutamates bracketed by arginines, lysines and glutamines in a pattern reminiscent of the repetitive motif found in the protein trichohyalin. The ankyrin-like repeats and a 66 amino acid peptide in the C terminus show significant sequence similarity to proteins encoded by the forked gene of Drosophila. A fusion protein containing the C-terminal 378 amino acids of espin was found to bind with high affinity (Kd = approximately 10 nM) to F-actin in vitro with a stoichiometry of approximately 1 espin per 6 actin monomers. When expressed by transfected NRK fibroblasts, the same C-terminal fragment of espin was observed to decorate actin fibers or cables. On the basis of its structure, localization and properties, we hypothesize that espin is involved in linking actin filaments to each other or to membranes, thereby potentially playing a key role in the organization and function of the ectoplasmic specialization.
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Affiliation(s)
- J R Bartles
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, IL 60611, USA.
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Guraya SS. The comparative cell biology of accessory somatic (or Sertoli) cells in the animal testis. INTERNATIONAL REVIEW OF CYTOLOGY 1995; 160:163-220. [PMID: 7558683 DOI: 10.1016/s0074-7696(08)61555-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A comparative account is given of recent advances in the cell biology of testicular accessory somatic (or Sertoli) cells in mammals, nonmammalian vertebrates, and invertebrates by comparing and contrasting their structure and function. Their structure is discussed in relation to the nucleus, cytoplasmic organelles, and inclusions (lipids, the cytoskeleton, junctional complexes, and blood-testis barrier, which show great diversity and a variable testicular architecture), and mode of spermatogenesis. A very limited somatic cell-germinal association or its complete absence is observed in some groups of invertebrates. Wherever the somatic accessory cells are present, their comparative functions are discussed in relation to (1) mechanical support and nutrition; (2) translocation of germ cells; (3) paracrine regulation and a combination of male germ cell proliferation and differentiation by secretion of regulatory proteins, including peptide growth factors and hormones; (4) phagocytosis; (5) steroid hormone synthesis and metabolism; and (6) spermiation. Comparative cellular and molecular aspects of Sertoli cell-germ cell and peritubular cell interactions and the regulatory (hormonal) mechanisms involved as well as gaps in our knowledge about the molecular aspects of these interactions are emphasized for a better understanding of diversity in the patterns and regulation of spermatogenesis in animals.
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Affiliation(s)
- S S Guraya
- Department of Zoology, Punjab Agricultural University, Ludhiana, India
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Pfeiffer DC, Vogl AW. Ectoplasmic ("junctional") specializations in Sertoli cells of the rooster and turtle: evolutionary implications. Anat Rec (Hoboken) 1993; 235:33-50. [PMID: 8417627 DOI: 10.1002/ar.1092350105] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Ectoplasmic specializations are complex actin-containing structures found at certain sites of intercellular attachment in Sertoli cells. Current evidence indicates that these structures are a form of actin-associated adhesion junction. In the turtle (Pseudemys scripta) and rooster (Gallus domesticus) ectoplasmic specializations are known to occur adjacent to sites of attachment to elongate spermatids and are characterized by a layer of "loosely" cross-linked actin filaments that lies next to the plasma membrane. In the turtle, a cistern of endoplasmic reticulum is associated with the cytoplasmic face of the filament layer. We have found that, in fixed frozen sections of turtle and rooster testes, immunological probes for myosin II react with epithelial regions that also stain with probes for filamentous actin and that are known to be sites at which ectoplasmic specializations occur. Furthermore, when exposed to standard contraction buffers, the diameters of glycerinated ectoplasmic specializations of the turtle are statistically smaller than those of the same structures exposed to control buffers. We interpret these smaller diameters as being produced by the contraction of actin bundles within the ectoplasmic specializations. Our results indicate that ectoplasmic specializations in the rooster and turtle, unlike those in mammals, possess contractile properties. We speculate that ectoplasmic specializations in eutherian mammals may have evolved from actin-associated adhesion junctions in which the actin bundles were initially contractile and from which myosin II was secondarily lost.
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Affiliation(s)
- D C Pfeiffer
- Department of Anatomy, Faculty of Medicine, University of British Columbia, Vancouver, Canada
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Abstract
The Sertoli cell extends from the basement membrane of the seminiferous tubule towards its lumen; it sends cytoplasmic processes which envelop different generations of germ cells. The use of Sertoli cell culture began to develop in 1975. To reduce germ cell contamination immature animals are generally used as Sertoli cell donors. Sertoli cell mitosis essentially occurs in sexually immature testes in mammals; mitosis of these cells is observed in vitro during a limited period of time. Sertoli cells in vivo perform an impressive range of functions: structural support of the seminiferous epithelium, displacement of germ cells and release of sperm; formation of the Sertoli cell blood-testis barrier; secretion of factors and nutrition of germ cells; phagocytosis of degenerating germ cells and of germ cell materials. Some of the Sertoli cell functions can be studied in vitro. The recent development of Sertoli cell culture on permeable supports (with or without extracellular matrix) has resulted in progress in understanding the vectorial secretion of several Sertoli cell markers. In addition to FSH and testosterone, several other humoral factors are known to influence Sertoli cell function. Furthermore, myoid cells bordering the tubules as well as germ cells are capable of regulating Sertoli cell activity. Sertoli cells are the most widely used testicular cells for in vitro toxicology. The testis is highly vulnerable to xenobiotics and radiations, yet the number of studies undertaken in this field is insufficient and should be drastically increased.
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Affiliation(s)
- B Jégou
- CJF INSERM 91-04, Université de Rennes I, Bretagne, France
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