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Nguyen HT, Martin LJ. Classical cadherins in the testis: how are they regulated? Reprod Fertil Dev 2023; 35:641-660. [PMID: 37717581 DOI: 10.1071/rd23084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 08/31/2023] [Indexed: 09/19/2023] Open
Abstract
Cadherins (CDH) are crucial intercellular adhesion molecules, contributing to morphogenesis and creating tissue barriers by regulating cells' movement, clustering and differentiation. In the testis, classical cadherins such as CDH1, CDH2 and CDH3 are critical to gonadogenesis by promoting the migration and the subsequent clustering of primordial germ cells with somatic cells. While CDH2 is present in both Sertoli and germ cells in rodents, CDH1 is primarily detected in undifferentiated spermatogonia. As for CDH3, its expression is mainly found in germ and pre-Sertoli cells in developing gonads until the establishment of the blood-testis barrier (BTB). This barrier is made of Sertoli cells forming intercellular junctional complexes. The restructuring of the BTB allows the movement of early spermatocytes toward the apical compartment as they differentiate during a process called spermatogenesis. CDH2 is among many junctional proteins participating in this process and is regulated by several pathways. While cytokines promote the disassembly of the BTB by enhancing junctional protein endocytosis for degradation, testosterone facilitates the assembly of the BTB by increasing the recycling of endocytosed junctional proteins. Mitogen-activated protein kinases (MAPKs) are also mediators of the BTB kinetics in many chemically induced damages in the testis. In addition to regulating Sertoli cell functions, follicle stimulating hormone can also regulate the expression of CDH2. In this review, we discuss the current knowledge on regulatory mechanisms of cadherin localisation and expression in the testis.
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Affiliation(s)
- Ha Tuyen Nguyen
- Biology Department, Université de Moncton, Moncton, NB E1A 3E9, Canada
| | - Luc J Martin
- Biology Department, Université de Moncton, Moncton, NB E1A 3E9, Canada
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2
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Wang JM, Li ZF, Qi HY, Zhao Z, Yang WX. es-Arp3 and es-Eps8 regulate spermatogenesis via microfilaments in the seminiferous tubule of Eriocheir sinensis. Tissue Cell 2023; 81:102028. [PMID: 36709695 DOI: 10.1016/j.tice.2023.102028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/13/2022] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Spermatogenesis is a complicated process that includes spermatogonia differentiation, spermatocytes meiosis, spermatids spermiogenesis and final release of spermatozoa. Actin-related protein 3 (Arp3) and epidermal growth factor receptor pathway substrate 8 (Eps8) are two actin binding proteins that regulate cell adhesion in seminiferous tubules during mammalian spermatogenesis. However, the functions of these two proteins during spermatogenesis in nonmammalian species, especially Crustacea, are still unknown. Here, we cloned es-Arp3 and es-Eps8 from the testis of Chinese mitten crab Eriocheir sinensis. es-Arp3 and es-Eps8 were located in spermatocytes, spermatids and spermatozoa. Knockdown of es-Arp3 and es-Eps8 in vivo caused morphological changes to seminiferous tubules including delayed spermatozoa release, shedding of germ cells and vacuoles. Filamentous-actin (F-actin) filaments network was disorganized due to deficiency of es-Arp3 and es-Eps8. Accompanying this, four junctional proteins (α-catenin, β-catenin, pinin and ZO1) displayed abnormal expression levels as well as penetrating biotin signals in seminiferous tubules. We also used the Arp2/3 complex inhibitor CK666 to block es-Arp3 activity and supported es-Arp3 knockdown results. In summary, our study demonstrated for the first time that es-Arp3 and es-Eps8 are important for spermatogenesis via regulating microfilament-mediated cell adhesion in Eriocheir sinensis.
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Affiliation(s)
- Jia-Ming Wang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhen-Fang Li
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hong-Yu Qi
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhan Zhao
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
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3
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Wang L, Zhang R, Wu B, Yu Y, Li W, Li S, Liu C. Autophagy mediated tubulobulbar complex components degradation is required for spermiation. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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4
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Zhang Y. SPATA33 affects the formation of cell adhesion complex by interacting with CTNNA3 in TM4 cells. Cell Tissue Res 2022; 389:145-157. [PMID: 35536443 DOI: 10.1007/s00441-022-03631-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/26/2022] [Indexed: 11/25/2022]
Abstract
Communication between Sertoli cell is essential during spermatogenesis and testicular development in mice, and the dynamic balance of this communication is regulated by some adhesion proteins. In this study, we found that SPATA33 and CTNNA3 were involved in this process. Quantitative real-time PCR and western blotting showed similar trend of expression of two proteins in the testis of mice of different ages. Subsequently, CRISPR-Cas9 technique was used to prepare Spata33 knockout cell lines with TM4 cells, cell wound scratch assay showed that Spata33 gene knockout affected cell migration, and flow cytometry assay showed that Spata33 knockout resulted in a decreased percentage of G1 phase cells in TM4 cell line. In addition, phalloidin staining assay showed that Spata33 gene knockout disrupted the formation of F-actin. Moreover, the protein immunoprecipitation experiment showed the interaction between SPATA33 and CTNNA3, which affected the interaction between CTNNA3 and CTNNB1. SPATA33 inhibits the formation of CDH1-CTNNB1-CTNNA3 complex through its interaction with CTNNA3, thus weakening adhesion between Sertoli cell and promoting cell migration.
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Affiliation(s)
- Ying Zhang
- Luoyang Normal University, Luoyang, 471934, Henan, China.
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Cervero P, Vrenken K, Klose M, Rehm K, Linder S. Nectin stabilization at adherens junctions is counteracted by Rab5a-dependent endocytosis. Eur J Cell Biol 2021; 100:151184. [PMID: 34826799 DOI: 10.1016/j.ejcb.2021.151184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 11/19/2022] Open
Abstract
Cell-cell junctions undergo constant remodeling, which is crucial for the control of vascular integrity. Indeed, transport of junctional components such as cadherins is understood in increasing depth. However, little is known about the respective pathways regulating localization of nectin at cell-cell junctions. Here, we performed an siRNA-based screen of vesicle regulators of the RabGTPase family, leading to the identification of a novel role for Rab5a in the endocytosis nectin-2 at adherens junctions of primary human endothelial cells (HUVEC). Confocal microscopy experiments revealed disordered nectin-2 localization at adherens junctions upon Rab5a depletion. In addition, internalized nectin-2 was shown to prominently localize to Rab5a-positive vesicles in both fixed and living cells. As shown previously, nectin-2 stabilization at junctions is achieved via drebrin-dependent coupling to the subcortical actin cytoskeleton. Consistently, depletion of drebrin in this study leads to enhanced internalization of nectin-2 from junctions. Strikingly, simultaneous silencing of Rab5a and drebrin restored the junctional localization of nectin-2, pointing to Rab5a as counteracting the drebrin-dependent stabilization of nectin-2 at adherens junctions. This mechanism could be further validated by transendothelial resistance measurements. Collectively, our results identify Rab5a as a key player in the endocytosis of nectin-2 and thus in the regulation of adherens junction integrity in primary human endothelial cells.
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Affiliation(s)
- Pasquale Cervero
- Institut für medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Kirsten Vrenken
- Institut für medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Eppendorf, Martinistr. 52, 20246 Hamburg, Germany; Laboratory of Pediatric Oncology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, P.O.Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Matthias Klose
- Institut für medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Kerstin Rehm
- Institut für medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
| | - Stefan Linder
- Institut für medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
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Palia P, Adams A, Sriram A, Vogl AW. Cortactin knockdown results in disruption of basal TBCs and alters turnover of Sertoli cell ESs in Rattus norvegicus†. Biol Reprod 2021; 105:1330-1343. [PMID: 34426822 DOI: 10.1093/biolre/ioab161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 07/05/2021] [Accepted: 08/17/2021] [Indexed: 11/13/2022] Open
Abstract
Here we explore the prediction that long-term knockdown of cortactin (CTTN), a component of tubulobulbar complexes (TBCs), disrupts TBCs in Sertoli cells and alters the turnover of basal ectoplasmic specializations (ESs). In rats, intratesticular injections of siRNA targeting CTTN (siCTTN) in one testis and nontargeting siRNA (siControl) in the contralateral testis were done on days 0, 2, 4, 6, and 8. The experiment was terminated on day 9 and testes were analyzed by either western blotting, or by stimulated emission depletion (STED), electron and/or conventional fluorescence microscopy. Levels of CTTN were successfully knocked down in experimental testes compared to controls. When cryo-sections were labeled for actin filaments, or CTTN, and oxysterol binding protein-related protein 9 (ORP9) and analyzed by STED microscopy, TBCs were "less distinct" than in tubules of the same stages from control testes. When analyzed by electron microscopy, redundant clumps of basal actin filament containing ESs were observed in experimental sections. Using labeling of actin filaments in ESs, thresholding techniques were used to calculate the number of pixels above threshold per unit length of tubule wall in seminiferous tubules at Stage VII. Median values were higher in experimental testes relative to controls in the four animals analyzed. Although we detected subtle differences in ES turnover, we were unable to demonstrate changes in spermatocyte translocation or in the levels of junction proteins at the sites. Our results are the first to demonstrate that perturbation of basal TBCs alters the turnover of actin-related junctions (ESs).
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Affiliation(s)
- Prunveer Palia
- Life Sciences Institute and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Arlo Adams
- Life Sciences Institute and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aarati Sriram
- Life Sciences Institute and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - A Wayne Vogl
- Life Sciences Institute and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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DNase activity in human seminal plasma and follicular fluid and its inhibition by follicular fluid chelating agents. Reprod Biomed Online 2021; 43:1079-1086. [PMID: 34753679 DOI: 10.1016/j.rbmo.2021.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/30/2021] [Accepted: 09/20/2021] [Indexed: 11/23/2022]
Abstract
RESEARCH QUESTION What is the mechanism by which human follicular fluid inhibits seminal plasma DNase activity? DESIGN Human genomic DNA was incubated with human follicular fluid and seminal plasma (reaction mixture) under different experimental conditions; increasing volumes of human follicular fluid; proteinase K digested or heat inactivated human follicular fluid; and the addition of Ca2+ or Mg2+ to the reaction mixture. RESULTS Increasing volume of human follicular fluid resulted in a dose-dependent inhibition of seminal plasma DNase activity. Inhibition was not caused by proteins in the human follicular fluid as digestion with proteinase K or heat inactivation of human follicular fluid failed to abolish its inhibitory effect. Addition of divalent cations resulted in a reversion of the inhibitory effect, providing evidence that human follicular fluid inhibition of seminal plasma DNase activity seems to be mediated by a compound with chelating activity. Furthermore, incubation of genomic DNA with human follicular fluid in the presence of divalent cations served to elicit the existence of DNase activity. CONCLUSIONS Human follicular fluid seems to contain a molecule or molecules with chelating capacity that inhibits DNase activity of both follicular fluid and seminal plasma. Our findings provide new insight to understanding sperm preservation and the physiology of fertilization biology.
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Zakrzewski P, Suwińska A, Lenartowski R, Rędowicz MJ, Buss F, Lenartowska M. Myosin VI maintains the actin-dependent organization of the tubulobulbar complexes required for endocytosis during mouse spermiogenesis†‡. Biol Reprod 2021; 102:863-875. [PMID: 31901088 PMCID: PMC7124960 DOI: 10.1093/biolre/ioz232] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/16/2019] [Accepted: 12/30/2019] [Indexed: 12/15/2022] Open
Abstract
Myosin VI (MYO6) is an actin-based motor that has been implicated in a wide range of cellular processes, including endocytosis and the regulation of actin dynamics. MYO6 is crucial for actin/membrane remodeling during the final step of Drosophila spermatogenesis, and MYO6-deficient males are sterile. This protein also localizes to actin-rich structures involved in mouse spermiogenesis. Although loss of MYO6 in Snell's waltzer knock-out (KO) mice causes several defects and shows reduced male fertility, no studies have been published to address the role of MYO6 in sperm development in mouse. Here we demonstrate that MYO6 and some of its binding partners are present at highly specialized actin-based structures, the apical tubulobulbar complexes (TBCs), which mediate endocytosis of the intercellular junctions at the Sertoli cell-spermatid interface, an essential process for sperm release. Using electron and light microscopy and biochemical approaches, we show that MYO6, GIPC1 and TOM1/L2 form a complex in testis and localize predominantly to an early endocytic APPL1-positive compartment of the TBCs that is distinct from EEA1-positive early endosomes. These proteins also associate with the TBC actin-free bulbular region. Finally, our studies using testis from Snell's waltzer males show that loss of MYO6 causes disruption of the actin cytoskeleton and disorganization of the TBCs and leads to defects in the distribution of the MYO6-positive early APPL1-endosomes. Taken together, we report here for the first time that lack of MYO6 in mouse testis reduces male fertility and disrupts spatial organization of the TBC-related endocytic compartment during the late phase of spermiogenesis.
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Affiliation(s)
- Przemysław Zakrzewski
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, Torun, Poland.,Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, Torun, Poland
| | - Anna Suwińska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, Torun, Poland.,Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, Torun, Poland
| | - Robert Lenartowski
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, Torun, Poland.,Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, Torun, Poland
| | - Maria Jolanta Rędowicz
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Folma Buss
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Marta Lenartowska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, Torun, Poland.,Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, Torun, Poland
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9
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Molecular insights into hormone regulation via signaling pathways in Sertoli cells: With discussion on infertility and testicular tumor. Gene 2020; 753:144812. [DOI: 10.1016/j.gene.2020.144812] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/17/2020] [Accepted: 05/22/2020] [Indexed: 02/07/2023]
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10
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Yan M, Li L, Mao B, Li H, Li SYT, Mruk D, Silvestrini B, Lian Q, Ge R, Cheng CY. mTORC1/rpS6 signaling complex modifies BTB transport function: an in vivo study using the adjudin model. Am J Physiol Endocrinol Metab 2019; 317:E121-E138. [PMID: 31112404 PMCID: PMC6689739 DOI: 10.1152/ajpendo.00553.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/30/2019] [Accepted: 05/05/2019] [Indexed: 12/13/2022]
Abstract
Studies have shown that the mTORC1/rpS6 signaling cascade regulates Sertoli cell blood-testis barrier (BTB) dynamics. For instance, specific inhibition of mTORC1 by treating Sertoli cells with rapamycin promotes the Sertoli cell barrier, making it "tighter." However, activation of mTORC1 by overexpressing a full-length rpS6 cDNA clone (i.e., rpS6-WT, wild type) in Sertoli cells promotes BTB remodeling, making the barrier "leaky." Also, there is an increase in rpS6 and p-rpS6 (phosphorylated and activated rpS6) expression at the BTB in testes at stages VIII-IX of the epithelial cycle, and it coincides with BTB remodeling to support the transport of preleptotene spermatocytes across the barrier, illustrating that rpS6 is a BTB-modifying signaling protein. Herein, we used a constitutively active, quadruple phosphomimetic mutant of rpS6, namely p-rpS6-MT of p-rpS6-S235E/S236E/S240E/S244E, wherein Ser (S) was converted to Glu (E) at amino acid residues 235, 236, 240, and 244 from the NH2 terminus by site-directed mutagenesis, for its overexpression in rat testes in vivo using the Polyplus in vivo jet-PEI transfection reagent with high transfection efficiency. Overexpression of this p-rpS6-MT was capable of inducing BTB remodeling, making the barrier "leaky." This thus promoted the entry of the nonhormonal male contraceptive adjudin into the adluminal compartment in the seminiferous epithelium to induce germ cell exfoliation. Combined overexpression of p-rpS6-MT with a male contraceptive (e.g., adjudin) potentiated the drug bioavailability by modifying the BTB. This approach thus lowers intrinsic drug toxicity due to a reduced drug dose, further characterizing the biology of BTB transport function.
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Affiliation(s)
- Ming Yan
- Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, New York
| | - Linxi Li
- Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, New York
- Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University , Wenzhou, Zhejiang , China
| | - Baiping Mao
- Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, New York
- Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University , Wenzhou, Zhejiang , China
| | - Huitao Li
- Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, New York
- Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University , Wenzhou, Zhejiang , China
| | - Stephen Y T Li
- Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, New York
| | - Dolores Mruk
- Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, New York
| | | | - Qingquan Lian
- Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University , Wenzhou, Zhejiang , China
| | - Renshan Ge
- Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University , Wenzhou, Zhejiang , China
| | - C Yan Cheng
- Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, New York
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Xiao X, Yang Y, Mao B, Cheng CY, Ni Y. Emerging role for SRC family kinases in junction dynamics during spermatogenesis. Reproduction 2019; 157:R85-R94. [PMID: 30608903 PMCID: PMC6602873 DOI: 10.1530/rep-18-0440] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 01/03/2019] [Indexed: 12/22/2022]
Abstract
SRC family kinases (SFKs) are known regulators of multiple cellular events, including cell movement, differentiation, proliferation, survival and apoptosis. SFKs are expressed virtually by all mammalian cells. They are non-receptor protein kinases that phosphorylate a variety of cellular proteins on tyrosine, leading to the activation of protein targets in response to environmental stimuli. Among SFKs, SRC, YES and FYN are the ubiquitously expressed and best studied members. In fact, SRC, the prototypical SFK, was the first tyrosine kinase identified in mammalian cells. Studies have shown that SFKs are regulators of cell junctions, and function in endocytosis and membrane trafficking to regulate junction restructuring events. Herein, we briefly summarize the recent findings in the field regarding the role of SFKs in the testis in regulating spermatogenesis, particularly in Sertoli-Sertoli and Sertoli-germ cell adhesion. While it is almost 50 years since the identification of the oncogene v-Src encoded by Rous sarcoma transforming virus, the understanding of SFK involvement during spermatogenesis in the testis remains far behind that in other epithelia and tissues. The goal of this review is to bridge this gap.
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Affiliation(s)
- Xiang Xiao
- Department of Reproductive Physiology, Zhejiang Academy of Medical Sciences, Hangzhou 310013, Zhejiang, China
| | - Yue Yang
- Department of Reproductive Physiology, Zhejiang Academy of Medical Sciences, Hangzhou 310013, Zhejiang, China
| | - Baiping Mao
- The Mary M. Woldford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, United States
| | - C. Yan Cheng
- The Mary M. Woldford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, United States
| | - Ya Ni
- Department of Reproductive Physiology, Zhejiang Academy of Medical Sciences, Hangzhou 310013, Zhejiang, China
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Adams A, Sriram A, Wayne Vogl A. Internalization of Intact Intercellular Junctions in the Testis by Clathrin/Actin-Mediated Endocytic Structures: Tubulobulbar Complexes. Anat Rec (Hoboken) 2018; 301:2080-2085. [PMID: 30312540 DOI: 10.1002/ar.23963] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/12/2018] [Accepted: 04/17/2018] [Indexed: 02/06/2023]
Abstract
Sertoli cells of the mammalian seminiferous epithelium form unique subcellular actin-related structures at intercellular junctions. The appearance of these so called "tubulobulbar complexes" (TBCs) precedes both sperm release at the apex of the epithelium and the movement of early spermatogenic cells out of the spermatogonial stem cell niche at the base of the epithelium. TBCs are considered to be part of the mechanism of junction endocytosis by Sertoli cells. The structures contain junction proteins and morphologically identifiable junctions, and are associated with markers of endocytosis. Here we review the current state of knowledge about the structure and function of TBCs. As the complexes form, they morphologically resemble and have the molecular signature of clathrin-coated pits with extremely long necks. As they mature, the actin filament networks around the "necks" of the structures progressively disassemble and the membrane cores expand or swell into distinct "bulbs". These bulbs acquire extensive membrane contact sites with associated cisternae of endoplasmic reticulum. Eventually the bulbs undergo scission and continue through endosomal compartments of the Sertoli cells. The morphology and composition of TBC indicates to us that the structures likely evolved from the basic clathrin-mediated endocytosis mechanism common to cells generally, and along the way they incorporated unique features to accommodate the cyclic turnover of massive and "intact" intercellular junctions that occurs during spermatogenesis. Anat Rec, 301:2080-2085, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Arlo Adams
- Department of Cellular and Physiological Sciences, Life Sciences Centre, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aarati Sriram
- Department of Cellular and Physiological Sciences, Life Sciences Centre, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - A Wayne Vogl
- Department of Cellular and Physiological Sciences, Life Sciences Centre, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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13
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Dynamic of VE-cadherin-mediated spermatid-Sertoli cell contacts in the mouse seminiferous epithelium. Histochem Cell Biol 2018; 150:173-185. [PMID: 29797291 DOI: 10.1007/s00418-018-1682-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2018] [Indexed: 02/04/2023]
Abstract
Spermatids are haploid differentiating cells that, in the meantime they differentiate, translocate along the seminiferous epithelium towards the tubule lumen to be just released as spermatozoa. The success of such a migration depends on dynamic of spermatid-Sertoli cell contacts, the molecular nature of which has not been well defined yet. It was demonstrated that the vascular endothelial cadherin (VEC) is expressed transitorily in the mouse seminiferous epithelium. Here, we evaluated the pattern of VEC expression by immunohistochemistry first in seminiferous tubules at different stages of the epithelial cycle when only unique types of germ cell associations are present. Changes in the pattern of VEC localization according to the step of spermatid differentiation were analysed in detail using testis fragments and spontaneously released germ cells. Utilizing the first wave of spermatogenesis as an in vivo model to have at disposal spermatids at progressive steps of differentiation, we checked for level of looser VEC association with the membrane by performing protein solubilisation under mild detergent conditions and assays through VEC-immunoblotting. Being changes in VEC solubilisation paralleled in changes in phosphotyrosine (pY) content, we evaluated if spermatid VEC undergoes Y658 phosphorylation and if this correlates with VEC solubilisation and spermatid progression in differentiation. Altogether, our study shows a temporally restricted pattern of VEC expression that culminates with the presence of round spermatids to progressively decrease starting from spermatid elongation. Conversely, pY658-VEC signs elongating spermatids; its intracellular polarized compartmentalization suggests a possible involvement of pY658-VEC in the acquisition of spermatid cell polarity.
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14
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Kumar A, Raut S, Balasinor NH. Endocrine regulation of sperm release. Reprod Fertil Dev 2018; 30:1595-1603. [DOI: 10.1071/rd18057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/02/2018] [Indexed: 01/11/2023] Open
Abstract
Spermiation (sperm release) is the culmination of a spermatid’s journey in the seminiferous epithelium. After a long association with the Sertoli cell, spermatids have to finally ‘let go’ of the support from Sertoli cells in order to be transported to the epididymis. Spermiation is a multistep process characterised by removal of excess spermatid cytoplasm, recycling of junctional adhesion molecules by endocytosis, extensive cytoskeletal remodelling and final spermatid disengagement. Successful execution of all these events requires coordinated regulation by endocrine and paracrine factors. This review focuses on the endocrine regulation of spermiation. With the aim of delineating how hormones control the various aspects of spermiation, this review provides an analysis of recent advances in research on the hormonal control of molecules associated with the spermiation machinery. Because spermiation is one of the most sensitive phases of spermatogenesis to variations in hormone levels, understanding their molecular control is imperative to advance our knowledge of the nuances of spermatogenesis and male fertility.
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15
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MicroRNAs in Sertoli cells: implications for spermatogenesis and fertility. Cell Tissue Res 2017; 370:335-346. [DOI: 10.1007/s00441-017-2667-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 06/30/2017] [Indexed: 12/12/2022]
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16
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Kumar A, Dumasia K, Deshpande S, Balasinor NH. Direct regulation of genes involved in sperm release by estrogen and androgen through their receptors and coregulators. J Steroid Biochem Mol Biol 2017; 171:66-74. [PMID: 28242260 DOI: 10.1016/j.jsbmb.2017.02.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/08/2017] [Accepted: 02/23/2017] [Indexed: 12/23/2022]
Abstract
Steroid hormones, estrogen and androgen, control transcription in various reproductive and non-reproductive tissues. Both hormones are known to be important for control of sperm release from the seminiferous epithelium (spermiation), a process characterized by extensive remodeling of actin filaments and endocytosis. Earlier studies with an estrogen (E2)-induced rat model of spermiation failure revealed genes involved in actin remodeling (Arpc1b and Evl) and endocytosis (Picalm, Eea1, and Stx5a) to be differentially regulated. Further, among these genes, Arpc1b and Evl were found to be estrogen-responsive whereas Eea1 and Stx5a were androgen-responsive and Picalm was responsive to both hormones in seminiferous tubule cultures. Yet, the mechanism by which these genes are regulated by estrogen and androgen in the testis was unclear. Here, we report the presence of a functional estrogen response element (ERE) upstream of Arpc1b and Evl genes and androgen response element (ARE) upstream of Picalm, Eea1, and Stx5a genes. Chromatin immunoprecipitation in control versus E2-treated testes revealed significant changes in estrogen receptor beta (ERβ) recruitment along with coregulators to the EREs upstream of Arpc1b and Evl genes and androgen receptor (AR) at AREs upstream of Picalm, Eea1, and Stx5a genes. Enrichment patterns of these EREs/AREs with coregulators, activating and repressing histone modifications along with RNA polymerase II recruitment, correlated with the observed expression patterns of these genes upon E2 treatment. Taken together, our results reveal direct targets of estrogen and androgen in the testes and provide insights into transcriptional control of sperm release by the two steroid hormones.
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Affiliation(s)
- Anita Kumar
- Department of Neuroendocrinology, National Institute for Research in Reproductive Health (ICMR), Parel, Mumbai 400012, India
| | - Kushaan Dumasia
- Department of Neuroendocrinology, National Institute for Research in Reproductive Health (ICMR), Parel, Mumbai 400012, India
| | - Sharvari Deshpande
- Department of Neuroendocrinology, National Institute for Research in Reproductive Health (ICMR), Parel, Mumbai 400012, India
| | - N H Balasinor
- Department of Neuroendocrinology, National Institute for Research in Reproductive Health (ICMR), Parel, Mumbai 400012, India.
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Lyon K, Adams A, Piva M, Asghari P, Moore ED, Vogl AW. Ca2+ signaling machinery is present at intercellular junctions and structures associated with junction turnover in rat Sertoli cells†. Biol Reprod 2017; 96:1288-1302. [DOI: 10.1093/biolre/iox042] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/08/2017] [Indexed: 11/13/2022] Open
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18
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Wen Q, Tang EI, Gao Y, Jesus TT, Chu DS, Lee WM, Wong CKC, Liu YX, Xiao X, Silvestrini B, Cheng CY. Signaling pathways regulating blood-tissue barriers - Lesson from the testis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:141-153. [PMID: 28450047 DOI: 10.1016/j.bbamem.2017.04.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 04/18/2017] [Accepted: 04/21/2017] [Indexed: 12/12/2022]
Abstract
Signaling pathways that regulate blood-tissue barriers are important for studying the biology of various blood-tissue barriers. This information, if deciphered and better understood, will provide better therapeutic management of diseases particularly in organs that are sealed by the corresponding blood-tissue barriers from systemic circulation, such as the brain and the testis. These barriers block the access of antibiotics and/or chemotherapeutical agents across the corresponding barriers. Studies in the last decade using the blood-testis barrier (BTB) in rats have demonstrated the presence of several signaling pathways that are crucial to modulate BTB function. Herein, we critically evaluate these findings and provide hypothetical models regarding the underlying mechanisms by which these signaling molecules/pathways modulate BTB dynamics. This information should be carefully evaluated to examine their applicability in other tissue barriers which shall benefit future functional studies in the field. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Qing Wen
- The Mary M. Woldford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, United States
| | - Elizabeth I Tang
- The Mary M. Woldford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, United States
| | - Ying Gao
- The Mary M. Woldford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, United States
| | - Tito T Jesus
- The Mary M. Woldford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, United States
| | - Darren S Chu
- The Mary M. Woldford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, United States
| | - Will M Lee
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Chris K C Wong
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Yi-Xun Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xiang Xiao
- Department of Reproductive Physiology, Zhejiang Academy of Medical Sciences, Hangzhou 310013, Zhejiang, China
| | | | - C Yan Cheng
- The Mary M. Woldford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, NY 10065, United States.
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Adams A, Wayne Vogl A. High Resolution Localization of Rab5, EEA1, and Nectin-3 to Tubulobulbar Complexes in the Rat Testis. Anat Rec (Hoboken) 2017; 300:1160-1170. [PMID: 28176461 DOI: 10.1002/ar.23563] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 09/27/2016] [Accepted: 10/02/2016] [Indexed: 11/10/2022]
Abstract
Tubulobulbar complexes are clathrin/actin-based structures that internalize intercellular junctions in the testis. They resemble coated pits with extremely long necks that are cuffed by dendritic actin networks. As the structures mature, a swollen region or bulb develops near the end of each complex. The bulbs lack actin cuffs and are closely associated with cisternae of endoplasmic reticulum. The bulbs expand and are internalized and enter endocytic compartments of the Sertoli cell. Previous immunofluorescence studies have demonstrated that markers for early endosomes (Rab5 and EEA1) are associated with tubulobulbar complexes and are localized at or near the ends of the structures. Here we use a pre-embedding immunoelectron microscopic technique to accurately localize these markers to apical tubulobulbar complexes that occur at junctions between Sertoli cells and spermatids. Staining for Rab5 occurs at bulbs, identified by the presence of two plasma membranes and a close association with cisternae of endoplasmic reticulum. EEA1 is associated with large vesicles that lack an association with the endoplasmic reticulum. Labeling for nectin-3, an adhesion junction protein in the spermatid plasma membrane, occurs at junctions, TBC bulbs, and in associated double membrane vesicles. Our results suggest that Rab5 associates with junction protein containing bulbs prior to their internalization and that EEA1 associates with the structures later and after internalization. We conclude that at tubulobulbar complexes in Sertoli cells of the seminiferous epithelium, the identity of 'bulbs' as putative early endosomes begins to be established prior to their undergoing scission or budding from their parent structures. Anat Rec, 300:1160-1170, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Arlo Adams
- Department of Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - A Wayne Vogl
- Department of Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
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20
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Zhang Z, Li W, Zhang Y, Zhang L, Teves ME, Liu H, Strauss JF, Pazour GJ, Foster JA, Hess RA, Zhang Z. Intraflagellar transport protein IFT20 is essential for male fertility and spermiogenesis in mice. Mol Biol Cell 2016; 27:mbc.E16-05-0318. [PMID: 27682589 PMCID: PMC5170554 DOI: 10.1091/mbc.e16-05-0318] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 09/06/2016] [Accepted: 09/20/2016] [Indexed: 12/22/2022] Open
Abstract
Intraflagellar transport (IFT) is a conserved mechanism thought to be essential for the assembly and maintenance of cilia and flagella. However, little is known about its role in mammalian sperm flagella formation. To fill this gap, we disrupted the Ift20 gene in male germ cells. Homozygous mutant mice were infertile with significantly reduced sperm counts and motility. In addition, abnormally shaped elongating spermatid heads and bulbous round spermatids were found in the lumen of the seminiferous tubules. Electron microscopy revealed increased cytoplasmic vesicles, fiber-like structures, abnormal accumulation of mitochondria and a decrease in mature lysosomes. The few developed sperm had disrupted axonemes and some retained cytoplasmic lobe components on the flagella. ODF2 and SPAG16L, two sperm flagella proteins failed to be incorporated into sperm tails of the mutant mice, and in the germ cells, both were assembled into complexes with lighter density in the absence of IFT20. Disrupting IFT20 did not significantly change expression levels of IFT88, a component of IFT-B complex, and IFT140, a component of IFT-A complex. Even though the expression level of an autophagy core protein that associates with IFT20, ATG16, was reduced in the testis of the Ift20 mutant mice, expression levels of other major autophagy markers, including LC3 and ubiquitin were not changed. Our studies suggest that IFT20 is essential for male fertility and spermiogenesis in mice, and its major function is to transport cargo proteins for sperm flagella formation. It also appears to be involved in removing excess cytoplasmic components.
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Affiliation(s)
- Zhengang Zhang
- Department of Gastroenterology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei, China, 430030 Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Wei Li
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Yong Zhang
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, 23298 Department of Dermatology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei, China, 430030
| | - Ling Zhang
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, 23298 School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430065
| | - Maria E Teves
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Hong Liu
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, 23298 School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, 430065
| | - Jerome F Strauss
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - James A Foster
- Department of Biology, Randolph-Macon College, Ashland, VA 23005
| | - Rex A Hess
- Comparative Biosciences, College of Veterinary Medicine, University of Illinois, 2001 S. Lincoln, Urbana, IL 61802-6199
| | - Zhibing Zhang
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
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Kumar A, Dumasia K, Deshpande S, Gaonkar R, Balasinor N. Actin related protein complex subunit 1b controls sperm release, barrier integrity and cell division during adult rat spermatogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1996-2005. [DOI: 10.1016/j.bbamcr.2016.04.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/28/2016] [Accepted: 04/20/2016] [Indexed: 12/18/2022]
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22
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Sriram A, Lyon KRP, Ho CD, Huynh N, Vogl AW. Actin Disruption Results in Altered Morphology of Basal Tubulobulbar Complexes in Rat Seminiferous Epithelium. Anat Rec (Hoboken) 2016; 299:1449-55. [PMID: 27348857 DOI: 10.1002/ar.23394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 05/29/2016] [Indexed: 11/11/2022]
Abstract
Basal tubulobulbar complexes (TBCs) that occur at attachment sites between neighboring Sertoli cells are subcellular machines that internalize intercellular junctions during movement of spermatocytes from basal to adluminal compartments of the seminiferous epithelium. Each complex consists of an elongate tubular extension of two attached plasma membranes, and is capped at its distal end by a clathrin-coated pit. The tubular region is surrounded by a cuff of actin arranged in a dendritic network. Near the end of the complex, a bulbous region forms that lacks the actin cuff but is closely associated with cisternae of endoplasmic reticulum. The bulb eventually buds from the complex and enters endocytic compartments of the Sertoli cell. Previous research has shown that when the actin network is perturbed using the actin filament-disruptor, cytochalasin D, apical tubulobulbar complexes that are associated with spermatids were associated with lower levels of actin, patchy actin networks and swollen tubular regions. Here we explored the effects of actin network perturbation on the morphology of basal tubulobulbar complexes in stage V seminiferous tubules. Isolated rat testes were perfused ex vivo for one hour with oxygenated Krebs-Henseleit buffer (with BSA) containing either 40 μM cytochalasin D or control solution containing DMSO and perfusion-fixed for electron microscopy. Compared to control, actin cuffs in drug-treated TBCs appeared less uniform and patchy. In addition, the tubular regions of the complexes appeared swollen. Our results are consistent with the conclusion that intact networks of actin filaments are required for maintaining the structural integrity of basal TBCs. Anat Rec, 299:1449-1455, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Aarati Sriram
- Department of Cellular and Physiological Sciences Faculty of Medicine, The University of British Columbia, Canada
| | - Kevin R P Lyon
- Department of Obstetrics and Gynaecology Faculty of Medicine, The University of British Columbia, Canada
| | - Clement Dallas Ho
- Department of Cellular and Physiological Sciences Faculty of Medicine, The University of British Columbia, Canada
| | - Nghi Huynh
- Department of Cellular and Physiological Sciences Faculty of Medicine, The University of British Columbia, Canada
| | - A Wayne Vogl
- Department of Cellular and Physiological Sciences Faculty of Medicine, The University of British Columbia, Canada. .,Department of Obstetrics and Gynaecology Faculty of Medicine, The University of British Columbia, Canada.
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23
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Ahmed N, Yufei H, Yang P, Muhammad Yasir W, Zhang Q, Liu T, Hong C, Lisi H, Xiaoya C, Chen Q. Cytological study on Sertoli cells and their interactions with germ cells during annual reproductive cycle in turtle. Ecol Evol 2016; 6:4050-64. [PMID: 27516863 PMCID: PMC4972231 DOI: 10.1002/ece3.2193] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 04/07/2016] [Accepted: 04/26/2016] [Indexed: 12/20/2022] Open
Abstract
Sertoli cells (SCs) play a central role in the development of germ cells within functional testes and exhibit varying morphology during spermatogenesis. This present study investigated the seasonal morphological changes in SCs in the reproductive cycle of Pelodiscus sinensis by light microscopy, transmission electron microscopy (TEM), and immunohistochemistry. During hibernation period with the quiescent of spermatogenesis, several autophagosomes were observed inside the SCs, the processes of which retracted. In early spermatogenesis, when the germ cells started to proliferate, the SCs contained numerous lipid droplets instead of autophagosomes. In late spermatogenesis, the SCs processes became very thin and contacted several round/elongated spermatids in pockets. At this time, abundant endoplasmic reticulum and numerous mitochondria were present in the SCs. The organization of the tight junctions and the adherens junctions between the SCs and germ cells also changed during the reproductive cycle. Moreover, SCs were involved in the formation of cytoplasmic bridges, phagophores, and exosome secretions during spermatogenesis. Tubulobulbar complexes (TBC) were also developed by SCs around the nucleus of the spermatid at the time of spermiation. Strong, positive expression of vimentin was noted on the SCs during late spermatogenesis compared with the hibernation stage and the early stage of spermatogenesis. These data provide clear cytological evidence about the seasonal changes in SCs, corresponding with their different roles in germ cells within the Chinese soft‐shelled turtle Pelodiscus sinensis.
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Affiliation(s)
- Nisar Ahmed
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China; Faculty of Veterinary and Animal Sciences LUAWMS Uthal 90150 Pakistan
| | - Huang Yufei
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China
| | - Ping Yang
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China
| | - Waqas Muhammad Yasir
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China
| | - Qian Zhang
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China
| | - Tengfei Liu
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China
| | - Chen Hong
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China
| | - Hu Lisi
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China
| | - Chu Xiaoya
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China
| | - Qiusheng Chen
- Laboratory of Animal Cell Biology and Embryology College of Veterinary Medicine Nanjing Agricultural University Nanjing 210095 China
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Liu C, Wang H, Shang Y, Liu W, Song Z, Zhao H, Wang L, Jia P, Gao F, Xu Z, Yang L, Gao F, Li W. Autophagy is required for ectoplasmic specialization assembly in sertoli cells. Autophagy 2016; 12:814-32. [PMID: 26986811 DOI: 10.1080/15548627.2016.1159377] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The ectoplasmic specialization (ES) is essential for Sertoli-germ cell communication to support all phases of germ cell development and maturity. Its formation and remodeling requires rapid reorganization of the cytoskeleton. However, the molecular mechanism underlying the regulation of ES assembly is still largely unknown. Here, we show that Sertoli cell-specific disruption of autophagy influenced male mouse fertility due to the resulting disorganized seminiferous tubules and spermatozoa with malformed heads. In autophagy-deficient mouse testes, cytoskeleton structures were disordered and ES assembly was disrupted. The disorganization of the cytoskeleton structures might be caused by the accumulation of a negative cytoskeleton organization regulator, PDLIM1, and these defects could be partially rescued by Pdlim1 knockdown in autophagy-deficient Sertoli cells. Altogether, our works reveal that the degradation of PDLIM1 by autophagy in Sertoli cells is important for the proper assembly of the ES, and these findings define a novel role for autophagy in Sertoli cell-germ cell communication.
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Affiliation(s)
- Chao Liu
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
| | - Hongna Wang
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
| | - Yongliang Shang
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
| | - Weixiao Liu
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China
| | - Zhenhua Song
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
| | - Haichao Zhao
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
| | - Lina Wang
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
| | - Pengfei Jia
- c State Key Laboratory of Molecular Developmental Biology and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences , Beijing , China
| | - Fengyi Gao
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China
| | - Zhiliang Xu
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
| | - Lin Yang
- c State Key Laboratory of Molecular Developmental Biology and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences , Beijing , China
| | - Fei Gao
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
| | - Wei Li
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
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25
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Pariante P, Dotolo R, Venditti M, Ferrara D, Donizetti A, Aniello F, Minucci S. First Evidence of DAAM1 Localization During the Post-Natal Development of Rat Testis and in Mammalian Sperm. J Cell Physiol 2016; 231:2172-84. [PMID: 26831620 DOI: 10.1002/jcp.25330] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 02/01/2016] [Indexed: 01/16/2023]
Abstract
Dishevelled-associated activator of morphogenesis 1 (DAAM1) is a formin-family protein involved in nucleation of unbranched actin filaments and in cytoskeletal organization through Wnt-Dishevelled PCP pathway, which participates in essential biological processes, such as cell polarity, movement, and adhesion during morphogenesis and organogenesis. While its role has been investigated during development and in somatic cells, its potential association with the germinal compartment and reproduction is still unexplored. In this work, we assessed the possible association of DAAM1 with the morphogenesis of rat testis. We studied its expression and profiled its localization versus actin and tubulin, during the first wave of spermatogenesis and in the adult gonad (from 7 to 60 dpp). We show that, in mitotic phases, DAAM1 shares its localization with actin in Sertoli cells, gonocytes, and spermatogonia. Later, during meiosis, both proteins are found in spermatocytes, while only actin is detectable at the forming blood-testis barrier. DAAM1, then, follows the development of the acrosome system throughout spermiogenesis, and it is finally retained inside the cytoplasmic droplet in mature gametes, as corroborated by additional immunolocalization data on both rat and human sperm. Unlike the DAAM1, actin keeps its localization in Sertoli cells, and tubulin is associated with their protruding cytoplasm during the process. Our data support, for the first time, the hypothesis of a role for DAAM1 in cytoskeletal organization during Mammalian testis morphogenesis and gamete progression, while also hinting at its possible investigation as a morphological marker of germ cell and sperm physiology. J. Cell. Physiol. 231: 2172-2184, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Paolo Pariante
- Dipartimento di Medicina Sperimentale, Sez. Fisiologia Umana e Funzioni Biologiche Integrate "F. Bottazzi", Seconda Università di Napoli, Napoli, Italy
| | - Raffaele Dotolo
- Dipartimento di Medicina Sperimentale, Sez. Fisiologia Umana e Funzioni Biologiche Integrate "F. Bottazzi", Seconda Università di Napoli, Napoli, Italy
| | - Massimo Venditti
- Dipartimento di Medicina Sperimentale, Sez. Fisiologia Umana e Funzioni Biologiche Integrate "F. Bottazzi", Seconda Università di Napoli, Napoli, Italy
| | - Diana Ferrara
- Dipartimento di Medicina Sperimentale, Sez. Fisiologia Umana e Funzioni Biologiche Integrate "F. Bottazzi", Seconda Università di Napoli, Napoli, Italy
| | - Aldo Donizetti
- Dipartimento di Biologia, Università di Napoli Federico II, Napoli, Italy
| | - Francesco Aniello
- Dipartimento di Biologia, Università di Napoli Federico II, Napoli, Italy
| | - Sergio Minucci
- Dipartimento di Medicina Sperimentale, Sez. Fisiologia Umana e Funzioni Biologiche Integrate "F. Bottazzi", Seconda Università di Napoli, Napoli, Italy
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26
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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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Mruk DD, Cheng CY. The Mammalian Blood-Testis Barrier: Its Biology and Regulation. Endocr Rev 2015; 36:564-91. [PMID: 26357922 PMCID: PMC4591527 DOI: 10.1210/er.2014-1101] [Citation(s) in RCA: 382] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 09/03/2015] [Indexed: 12/31/2022]
Abstract
Spermatogenesis is the cellular process by which spermatogonia develop into mature spermatids within seminiferous tubules, the functional unit of the mammalian testis, under the structural and nutritional support of Sertoli cells and the precise regulation of endocrine factors. As germ cells develop, they traverse the seminiferous epithelium, a process that involves restructuring of Sertoli-germ cell junctions, as well as Sertoli-Sertoli cell junctions at the blood-testis barrier. The blood-testis barrier, one of the tightest tissue barriers in the mammalian body, divides the seminiferous epithelium into 2 compartments, basal and adluminal. The blood-testis barrier is different from most other tissue barriers in that it is not only comprised of tight junctions. Instead, tight junctions coexist and cofunction with ectoplasmic specializations, desmosomes, and gap junctions to create a unique microenvironment for the completion of meiosis and the subsequent development of spermatids into spermatozoa via spermiogenesis. Studies from the past decade or so have identified the key structural, scaffolding, and signaling proteins of the blood-testis barrier. More recent studies have defined the regulatory mechanisms that underlie blood-testis barrier function. We review here the biology and regulation of the mammalian blood-testis barrier and highlight research areas that should be expanded in future studies.
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Affiliation(s)
- Dolores D Mruk
- Center for Biomedical Research, Population Council, New York, New York 10065
| | - C Yan Cheng
- Center for Biomedical Research, Population Council, New York, New York 10065
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Raju D, Schonauer S, Hamzeh H, Flynn KC, Bradke F, vom Dorp K, Dörmann P, Yildiz Y, Trötschel C, Poetsch A, Breiden B, Sandhoff K, Körschen HG, Wachten D. Accumulation of glucosylceramide in the absence of the beta-glucosidase GBA2 alters cytoskeletal dynamics. PLoS Genet 2015; 11:e1005063. [PMID: 25803043 PMCID: PMC4372435 DOI: 10.1371/journal.pgen.1005063] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 02/09/2015] [Indexed: 11/18/2022] Open
Abstract
Glycosphingolipids are key elements of cellular membranes, thereby, controlling a variety of cellular functions. Accumulation of the simple glycosphingolipid glucosylceramide results in life-threatening lipid storage-diseases or in male infertility. How glucosylceramide regulates cellular processes is ill defined. Here, we reveal that glucosylceramide accumulation in GBA2 knockout-mice alters cytoskeletal dynamics due to a more ordered lipid organization in the plasma membrane. In dermal fibroblasts, accumulation of glucosylceramide augments actin polymerization and promotes microtubules persistence, resulting in a higher number of filopodia and lamellipodia and longer microtubules. Similar cytoskeletal defects were observed in male germ and Sertoli cells from GBA2 knockout-mice. In particular, the organization of F-actin structures in the ectoplasmic specialization and microtubules in the sperm manchette is affected. Thus, glucosylceramide regulates cytoskeletal dynamics, providing mechanistic insights into how glucosylceramide controls signaling pathways not only during sperm development, but also in other cell types. During mammalian spermatogenesis, sperm with a head and a tail are formed from a round cell. This process is tightly regulated and involves the close interaction of somatic Sertoli cells and germ cells. Accumulation of the glycosphingolipid glucosylceramide in the absence of the beta-glucosidase GBA2 has been proposed to disturb sperm development, leading to morphological defects. However, the underlying mechanism is not known. Here, we demonstrate that accumulation of glucosylceramide in GBA2 knockout-mice controls the dynamics of the actin and microtubule cytoskeleton, which are crucial for sperm development. In particular, cytoskeletal structures at the interface between Sertoli and germ cells are disorganized, leading to malformation of the sperm head and a defect in acrosome formation. In summary, we provide mechanistic insights into how glucosylceramide controls cellular signaling and dysregulation of this essential glycosphingolipid leads to male infertility.
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Affiliation(s)
- Diana Raju
- Minerva Research Group—Molecular Physiology, Center of Advanced European Studies and Research, Bonn, Germany
| | - Sophie Schonauer
- Minerva Research Group—Molecular Physiology, Center of Advanced European Studies and Research, Bonn, Germany
| | - Hussein Hamzeh
- Minerva Research Group—Molecular Physiology, Center of Advanced European Studies and Research, Bonn, Germany
| | - Kevin C. Flynn
- Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE e.V.), Bonn, Germany
| | - Frank Bradke
- Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE e.V.), Bonn, Germany
| | - Katharina vom Dorp
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Bonn, Germany
| | - Peter Dörmann
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Bonn, Germany
| | - Yildiz Yildiz
- Innere Medizin am Landeskrankenhaus Bregenz, Bregenz, Austria
| | | | - Ansgar Poetsch
- Biochemie der Pflanzen, Ruhr-Universität Bochum, Bochum, Germany
| | - Bernadette Breiden
- Life and Medical Sciences Institute (LIMES) c/o Kekulé-Institute of Chemistry and Biochemistry, Bonn, Germany
| | - Konrad Sandhoff
- Life and Medical Sciences Institute (LIMES) c/o Kekulé-Institute of Chemistry and Biochemistry, Bonn, Germany
| | - Heinz G. Körschen
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, Bonn, Germany
| | - Dagmar Wachten
- Minerva Research Group—Molecular Physiology, Center of Advanced European Studies and Research, Bonn, Germany
- * E-mail:
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Kumar A, Dumasia K, Gaonkar R, Sonawane S, Kadam L, Balasinor NH. Estrogen and androgen regulate actin-remodeling and endocytosis-related genes during rat spermiation. Mol Cell Endocrinol 2015; 404:91-101. [PMID: 25637714 DOI: 10.1016/j.mce.2014.12.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/26/2014] [Accepted: 12/17/2014] [Indexed: 12/22/2022]
Abstract
Spermiation, the sperm release process, is imperative to male fertility and reproduction. Morphologically, it is characterized by removal of atypical adherens junctions called ectoplasmic specializations, and formation of transient endocytic devices called tubulobulbar complexes requiring cytoskeleton remodeling and recruitment of proteins needed for endocytosis. Earlier, estrogen administration to adult male rats was seen to cause spermiation failure due to disruption of tubulobulbar complexes. This was accompanied by reduction in intratesticular testosterone levels and increase in intratesticular estrogen along with deregulation of genes involved in cytoskeleton remodeling (Arpc1b, Evl and Capg) and endocytosis (Picalm, Eea1 and Stx5a). In the present study, we aim to understand the role of estrogen and androgen in regulating these genes independently using seminiferous tubule culture system treated with estrogen, androgen or agonists and antagonists of estrogen receptors. We find that transcripts of Arpc1b, Evl and Picalm are responsive to estrogen while those of Picalm, Eea1 and Stx5a are responsive to androgen. We also find that the estrogen regulation of Arpc1b and Evl is mediated through estrogen receptor β and that of Picalm occurs through estrogen receptors α and β. Localization of these proteins at or in the vicinity of tubulobulbar complexes reveals that ARPC1B, EVL, PICALM, EEA1 and STX5A seem to be involved in spermiation. Thus, estrogen and androgen regulate specific genes in seminiferous tubules that could play a role in spermiation.
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Affiliation(s)
- Anita Kumar
- Deparment of Neuroendocrinology, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - Kushaan Dumasia
- Deparment of Neuroendocrinology, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - Reshma Gaonkar
- Confocal Facility, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - Shobha Sonawane
- Confocal Facility, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - Leena Kadam
- Deparment of Neuroendocrinology, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - N H Balasinor
- Deparment of Neuroendocrinology, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India.
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O'Donnell L. Mechanisms of spermiogenesis and spermiation and how they are disturbed. SPERMATOGENESIS 2015; 4:e979623. [PMID: 26413397 DOI: 10.4161/21565562.2014.979623] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 10/16/2014] [Indexed: 11/19/2022]
Abstract
Haploid round spermatids undergo a remarkable transformation during spermiogenesis. The nucleus polarizes to one side of the cell as the nucleus condenses and elongates, and the microtubule-based manchette sculpts the nucleus into its species-specific head shape. The assembly of the central component of the sperm flagellum, known as the axoneme, begins early in spermiogenesis, and is followed by the assembly of secondary structures needed for normal flagella. The final remodelling of the mature elongated spermatid occurs during spermiation, when the spermatids line up along the luminal edge, shed their residual cytoplasm and are ultimately released into the lumen. Defects in spermiogenesis and spermiation are manifested as low sperm number, abnormal sperm morphology and poor motility and are commonly observed during reproductive toxicant administration, as well as in genetically modified mouse models of male infertility. This chapter summarizes the major physiological processes and the most commonly observed defects in spermiogenesis and spermiation, to aid in the diagnosis of the potential mechanisms that could be perturbed by experimental manipulation such as reproductive toxicant administration.
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Affiliation(s)
- Liza O'Donnell
- MIMR-PHI Institute of Medical Research ; Clayton, Victoria, Australia ; Department of Anatomy and Developmental Biology; Monash University ; Clayton, Victoria, Australia
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31
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Cheng CY. Toxicants target cell junctions in the testis: Insights from the indazole-carboxylic acid model. SPERMATOGENESIS 2015; 4:e981485. [PMID: 26413399 PMCID: PMC4581065 DOI: 10.4161/21565562.2014.981485] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 10/23/2014] [Indexed: 12/31/2022]
Abstract
There are numerous types of junctions in the seminiferous epithelium which are integrated with, and critically dependent on the Sertoli cell cytoskeleton. These include the basal tight junctions between Sertoli cells that form the main component of the blood–testis barrier, the basal ectoplasmic specializations (basal ES) and basal tubulobulbar complexes (basal TBC) between Sertoli cells; as well as apical ES and apical TBC between Sertoli cells and the developing spermatids that orchestrate spermiogenesis and spermiation. These junctions, namely TJ, ES, and TBC interact with actin microfilament-based cytoskeleton, which together with the desmosomal junctions that interact with the intermediate filament-based cytoskeleton plus the highly polarized microtubule-based cytoskeleton are working in concert to move spermatocytes and spermatids between the basal and luminal aspect of the seminiferous epithelium. In short, these various junctions are structurally complexed with the actin- and microtubule-based cytoskeleton or intermediate filaments of the Sertoli cell. Studies have shown toxicants (e.g., cadmium, bisphenol A (BPA), perfluorooctanesulfonate (PFOS), phthalates, and glycerol), and some male contraceptives under development (e.g., adjudin, gamendazole), exert their effects, at least in part, by targeting cell junctions in the testis. The disruption of Sertoli–Sertoli cell and Sertoli–germ cell junctions, results in the loss of germ cells from the seminiferous epithelium. Adjudin, a potential male contraceptive under investigation in our laboratory, produces loss of spermatids from the seminiferous tubules through disruption of the Sertoli cell spermatid junctions and disruption of the Sertoli cell cytoskeleton. The molecular and structural changes associated with adjudin administration are described, to provide an example of the profile of changes caused by disturbance of Sertoli-germ cell and also Sertoli cell-cell junctions.
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Affiliation(s)
- C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research; Center for Biomedical Research; Population Council ; New York, NY USA
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Li MW, Xiao X, Mruk DD, Lam YL, Lee WM, Lui WY, Bonanomi M, Silvestrini B, Cheng CY. Actin-binding protein drebrin E is involved in junction dynamics during spermatogenesis. SPERMATOGENESIS 2014; 1:123-136. [PMID: 22319661 DOI: 10.4161/spmg.1.2.16393] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The actin-based cytoskeleton plays a critical role in the seminiferous epithelium during spermatogenesis by conferring cell shape, adhesion, structural support and cell polarity to both Sertoli and developing germ cells, which are essential for spermatogonial stem cell renewal, maintenance of the stem cell niche, cell cycle progression, mitosis, meiosis, spermiogenesis and spermiation. However, few functional studies are found in the literature, which explore the functional significance of actin dynamics in these events. This by and large is due to a lack of information on the proteins that regulate actin dynamics. Herein, we report drebrin E is an integrated component of the apical ectoplasmic specialization (apical ES) and the basal ES at the blood-testis barrier (BTB) in the seminiferous epithelium of the adult rat testis. Using immunohistochemistry and dual-labeled immunofluorescence analysis, drebrin E was found to display a stage-specific localization at the apical ES, as well as at the basal ES at the BTB during the seminiferous epithelial cycle of spermatogenesis. Drebrin E was first detected in stage V tubules at the basal ES with the highest expression at the BTB at stages V and VI, but it diminished considerably by stages VII and VIII and was almost non-detectable until stage IV. At the apical ES, drebrin E was also first detected at stage V, surrounding the entire head of the elongating spermatid, but by stage VI its localization had "shifted" to localize most intensely and almost exclusively to the concave side of the spermatid head. In stage VII tubules, drebrin E co-localized with actin, as well as with two other actin regulatory proteins Eps8 (epidermal growth factor receptor pathway substrate 8, an actin capping and bundling protein) and Arp3 (actin-related protein 3, a component of the Arp2/3 complex known to regulate actin nucleation and branching). The localization of drebrin E at the apical ES was compromised following treatment of rats with adjudin, which is known to exert its destructive effects primarily at the apical ES by inducing premature loss of elongating/elongated spermatids from the epithelium, mimicking "spermiation." Instead of being restricted to the concave side of spermatid heads, drebrin E was found to be mis-localized in the seminiferous epithelium of adjudin-treated rats; it was also present on the convex side of elongating spermatids, but these cells were mis-oriented so that their heads no longer pointed toward the basement membrane. The expression of drebrin E by Sertoli cells was also found to be modulated by TGFβ3 and TNFα. Since Arp3, but not Eps8, was found to bind drebrin E; and cytokines were also shown to affect the cellular distribution of drebrin E and enhance the interaction between drebrin E and Arp3, these findings illustrate that cytokines may regulate BTB dynamics during the epithelial cycle by recruiting drebrin E and Arp3 to the BTB microenvironment to induce changes in the configuration of actin filament bundles at the basal ES. In summary, these findings illustrate drebrin E is working in concert with Arp3 to regulate actin filament bundles at both the apical and the basal ES in the testis, conferring adhesion and cell polarity at both sites during spermatogenesis.
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Affiliation(s)
- Michelle Wm Li
- Center for Biomedical Research; The Population Council; New York, NY USA
| | - Xiang Xiao
- Center for Biomedical Research; The Population Council; New York, NY USA
| | - Dolores D Mruk
- Center for Biomedical Research; The Population Council; New York, NY USA
| | - Yee-Ling Lam
- Center for Biomedical Research; The Population Council; New York, NY USA
| | - Will M Lee
- School of Biological Sciences; The University of Hong Kong; Hong Kong, China
| | - Wing-Yee Lui
- School of Biological Sciences; The University of Hong Kong; Hong Kong, China
| | | | | | - C Yan Cheng
- Center for Biomedical Research; The Population Council; New York, NY USA
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Tang EI, Xiao X, Mruk DD, Qian XJ, Mok KW, Jenardhanan P, Lee WM, Mathur PP, Cheng CY. Microtubule affinity-regulating kinase 4 (MARK4) is a component of the ectoplasmic specialization in the rat testis. SPERMATOGENESIS 2014; 2:117-126. [PMID: 22670221 PMCID: PMC3364792 DOI: 10.4161/spmg.20724] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During the seminiferous epithelial cycle of spermatogenesis, the ectoplasmic specialization (ES, a testis-specific adherens junction, AJ, type) maintains the polarity of elongating/elongated spermatids and confers adhesion to Sertoli cells in the seminiferous epithelium, and known as the apical ES. On the other hand, the ES is also found at the Sertoli-Sertoli cell interface at the blood-testis barrier (BTB) known as basal ES, which together with the tight junction (TJ), maintains Sertoli cell polarity and adhesion, creating a functional barrier that limits paracellular transport of substances across the BTB. However, the apical and basal ES are segregated and restricted to the adluminal compartment and the BTB, respectively. During the transit of preleptotene spermatocytes across the BTB and the release of sperm at spermiation at stage VIII of the seminiferous epithelial cycle, both the apical and basal ES undergo extensive restructuring to facilitate cell movement at these sites. The regulation of these events, in particular their coordination, remains unclear. Studies in other epithelia have shown that the tubulin cytoskeleton is intimately related to cell movement, and MARK [microtubule-associated protein (MAP)/microtubule affinity-regulating kinase] family kinases are crucial regulators of tubulin cytoskeleton stability. Herein MARK4, the predominant member of the MARK protein family in the testis, was shown to be expressed by both Sertoli and germ cells. MARK4 was also detected at the apical and basal ES, displaying highly restrictive spatiotemporal expression at these sites, as well as co-localizing with markers of the apical and basal ES. The expression of MARK4 was found to be stage-specific during the epithelial cycle, structurally associating with α-tubulin and the desmosomal adaptor plakophilin-2, but not with actin-based BTB proteins occludin, β-catenin and Eps8 (epidermal growth factor receptor pathway substrate 8, an actin bundling and barbed end capping protein). More importantly, it was shown that the expression of MARK4 tightly associated with the integrity of the apical ES because a diminished expression of MARK4 associated with apical ES disruption that led to the detachment of elongating/elongated spermatids from the epithelium. These findings thus illustrate that the integrity of apical ES, an actin-based and testis-specific AJ, is dependent not only on the actin filament network, but also on the tubulin-based cytoskeleton.
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Young JS, Vogl AW. Focal adhesion proteins Zyxin and Vinculin are co-distributed at tubulobulbar complexes. SPERMATOGENESIS 2014; 2:63-68. [PMID: 22553491 PMCID: PMC3341248 DOI: 10.4161/spmg.19391] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Tubulobulbar complexes (TBCs) are actin-related double-membrane invaginations formed at intercellular junctions in the seminiferous epithelium of mammalian testis. They occur at basal junction complexes between neighboring Sertoli cells and at apical junctions between Sertoli cells and spermatids. They are proposed to internalize intercellular junctions during the translocation of spermatocytes from basal to adluminal compartments of the seminiferous epithelium, and during sperm release from Sertoli cells. Although TBCs are specific to the seminiferous epithelium, they morphologically resemble podosomes in osteoclasts. Previously, we have reported that a key group of proteins consisting of N-WASp, Arp2/3, cortactin and dynamin that occur at podosomes also is present at TBCs. Here we explore the prediction that zyxin, a focal adhesion protein known to be present at podosomes, also is present at apical TBCs. A rabbit polyclonal anti-zyxin antibody (B71) was used to label fixed fragments and frozen sections of testis. In both fragments and sections, B71 labeled tubular regions of TBCs at apical sites of attachment between Sertoli cells and spermatids, in addition to being localized at actin related intercellular adhesion junctions termed ectoplasmic specializations. Although the function of zyxin at TBCs has yet to be determined, the protein is known to interact with the cytoplasmic domain of integrins at focal adhesions, and integrins are known to be present in TBCs.
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Affiliation(s)
- J'nelle S Young
- Department of Cellular and Physiological Sciences; Faculty of Medicine; Life Sciences Centre; The University of British Columbia; Vancouver, BC Canada
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Cheng CY, Mruk DD. Actin binding proteins and spermiogenesis: Some unexpected findings. SPERMATOGENESIS 2014; 1:99-104. [PMID: 22319657 DOI: 10.4161/spmg.1.2.16913] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 06/05/2011] [Accepted: 06/07/2011] [Indexed: 12/18/2022]
Abstract
Drebrin E, an actin-binding protein lacking intrinsic activity in the regulation of actin dynamics (e.g., polymerization, capping, nucleation, branching, cross-linking, bundling and severing), is known to recruit actin regulatory proteins to a specific cellular site. Herein, we critically evaluate recent findings in the field which illustrate that drebrin E works together with two other actin-binding proteins, namely Arp3 (actin-related protein 3, a component of the Arp2/3 complex that simultaneously controls actin nucleation for polymerization and branching of actin filaments) and Eps8 (epidermal growth factor receptor pathway substrate 8 that controls capping of the barbed ends of actin filaments, as well as actin filament bundling) to regulate the homeostasis of F-actin filament bundles at the ectoplasmic specialization (ES), a testis-specific atypical adherens junction (AJ) in the seminiferous epithelium. This is mediated by the strict temporal and spatial expression of these three actin-binding proteins at the apical and basal ES at the Sertoli cell-spermatid (step 8-19) and Sertoli-Sertoli cell interface, respectively, during the seminiferous epithelial cycle of spermatogenesis. In this Commentary, we put forth a possible model by which drebrin E may be acting as a platform upon which proteins (e.g., Arp3) that are needed to alter the conformation of actin filament bundles at the ES can be recruited to the site, thus facilitating changes in cell shape and cell position in the epithelium during spermiogenesis and spermiation. In short, drebrin E may be acting as a "logistic" distribution center to manage different regulatory proteins at the apical ES, thereby regulating the dynamics of actin filament bundles and modulating the plasticity of the apical ES. This would allow adhesion to be altered continuously throughout the epithelial cycle to accommodate spermatid movement in the seminiferous epithelium during spermiogenesis and spermiation. We also describe a hypothetical model, upon which functional studies can be designed in the future.
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Affiliation(s)
- C Yan Cheng
- Center for Biomedical Research; The Population Council; New York, NY USA
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Gilibili RR, Vogl AW, Chang TKH, Bandiera SM. Localization of Cytochrome P450 and Related Enzymes in Adult Rat Testis and Downregulation by Estradiol and Bisphenol A. Toxicol Sci 2014; 140:26-39. [DOI: 10.1093/toxsci/kfu070] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
The transport of germ cells across the seminiferous epithelium is composed of a series of cellular events during the epithelial cycle essential to the completion of spermatogenesis. Without the timely transport of spermatids during spermiogenesis, spermatozoa that are transformed from step 19 spermatids in the rat testis fail to reach the luminal edge of the apical compartment and enter the tubule lumen at spermiation, thereby arriving the epididymis for further maturation. Step 19 spermatids and/or sperms that remain in the epithelium beyond stage VIII of the epithelial cycle will be removed by the Sertoli cell via phagocytosis to form phagosomes and be degraded by lysosomes, leading to subfertility and/or infertility. However, the biology of spermatid transport, in particular the final events that lead to spermiation remain elusive. Based on recent data in the field, we critically evaluate the biology of spermiation herein by focusing on the actin binding proteins (ABPs) that regulate the organization of actin microfilaments at the Sertoli-spermatid interface, which is crucial for spermatid transport during this event. The hypothesis we put forth herein also highlights some specific areas of research that can be pursued by investigators in the years to come.
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Cheng CY, Lie PPY, Wong EWP, Mruk DD. Focal adhesion kinase and actin regulatory/binding proteins that modulate F-actin organization at the tissue barrier: Lesson from the testis. Tissue Barriers 2014; 1:e24252. [PMID: 24665388 PMCID: PMC3875635 DOI: 10.4161/tisb.24252] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 03/07/2013] [Accepted: 03/09/2013] [Indexed: 11/28/2022] Open
Abstract
Focal adhesion kinase (FAK), as its name implied, is an important mediator of integrin-based signaling function in mammalian cells at the focal adhesion complex (FAC, also known as focal contact) at the cell-extracellular matrix interface. FAK is intimately related to cell movement, such as in macrophages, fibroblasts and also tumor cells. In the testis, however, FAK and two of its phosphorylated forms, p-FAK-Tyr407 and -Tyr397, are not found at the FAC since there is no ultrastructure analogous or similar to FAC in the mammalian testis vs. other epithelia. Instead, FAK and its two phosphorylated forms are detected along the seminiferous epithelium in the rat testis at the cell-cell interface in a testis-specific adherens junction (AJ) known as the ectoplasmic specialization (ES). ES is an F-actin-rich ultrastructure in which bundles of actin filaments are sandwiched in-between plasma membrane and cisternae of endoplasmic reticulum not found in other mammalian epithelial/endothelial cells. The ES is restricted to the interface of Sertoli cells and spermatids (step 8–19) known as the apical ES, and to the Sertoli cell-cell interface known as the basal ES. Interestingly, the basal ES is also an integrated component of the blood-testis barrier (BTB), coexisting with tight junction (TJ) and gap junction (GJ), and it is conceivable that actin filament bundles at the ES undergo extensive organization, converting from their “bundled” to “de-bundled/branching” configuration to facilitate transport of germ cells across the epithelium and at the BTB during the epithelial cycle. A recent report (Lie et al. PNAS 109:12562–12567, 2012) has demonstrated that the stage-specific and spatiotemporal expression of p-FAK-Tyr407 and -Tyr397 are crucial to the regulation of these events via their stage-specific and spatiotemporal expression during the epithelial cycle mediated by their effects on the organization of the actin filament bundles at the ES, involving actin binding/regulatory proteins. In this Commentary, we will critically evaluate these findings in light of other recent reports in the field. While these ideas are based on studies in the BTB in the rat testis, this information should be applicable and helpful to investigators studying other tissue barriers.
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Affiliation(s)
- C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research; Center for Biomedical Research; Population Council; New York, NY USA
| | - Pearl P Y Lie
- The Mary M. Wohlford Laboratory for Male Contraceptive Research; Center for Biomedical Research; Population Council; New York, NY USA
| | - Elissa W P Wong
- The Mary M. Wohlford Laboratory for Male Contraceptive Research; Center for Biomedical Research; Population Council; New York, NY USA
| | - Dolores D Mruk
- The Mary M. Wohlford Laboratory for Male Contraceptive Research; Center for Biomedical Research; Population Council; New York, NY USA
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The dynamic of the apical ectoplasmic specialization between spermatids and Sertoli cells: the case of the small GTPase Rap1. BIOMED RESEARCH INTERNATIONAL 2014; 2014:635979. [PMID: 24719879 PMCID: PMC3955676 DOI: 10.1155/2014/635979] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 01/19/2014] [Indexed: 12/31/2022]
Abstract
Despite advances in assisted reproductive technologies, infertility remains a consistent health problem worldwide. Spermiation is the process through which mature spermatids detach from the supporting Sertoli cells and are released into the tubule lumen. Spermiation failure leads to lack of mature spermatozoa and, if not occasional, could result into azoospermia, major cause of male infertility in human population. Spermatids are led through their differentiation into spermatozoa by the apical ectoplasmic specialization (aES), a testis-specific, actin-based anchoring junction restricted to the Sertoli-spermatid interface. The aES helps spermatid movement across the seminiferous epithelium, promotes spermatid positioning, and prevents the release of immature spermatozoa. To accomplish its functions, aES needs to undergo tightly and timely regulated restructuring. Even if components of aES are partly known, the mechanism/s through which aES is regulated remains still elusive. In this review, we propose a model by which the small GTPase Rap1 could regulate aES assembly/remodelling. The characterization of key players in the dynamic of aES, such as Rap1, could open new possibility to develop prognostic, diagnostic, and therapeutic approaches for male patients under treatment for infertility as well as it could lead to the identification of new target for male contraception.
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Upadhyay RD, Kumar A, Balasinor NH. Localization of proteins involved in endocytosis at tubulobulbar complexes in rat testes. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/arsci.2014.21001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Vogl AW, Du M, Wang XY, Young JS. Novel clathrin/actin-based endocytic machinery associated with junction turnover in the seminiferous epithelium. Semin Cell Dev Biol 2013; 30:55-64. [PMID: 24280271 DOI: 10.1016/j.semcdb.2013.11.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 11/13/2013] [Accepted: 11/18/2013] [Indexed: 01/25/2023]
Abstract
Tubulobulbar complexes are elaborate clathrin/actin related structures that form at sites of intercellular attachment in the seminiferous epithelium of the mammalian testis. Here we summarize what is currently known about the morphology and molecular composition of these structures and review evidence that the structures internalize intercellular junctions both at apical sites of Sertoli cell attachment to spermatids, and at basal sites where Sertoli cells form the blood-testis barrier. We present updated models of the sperm release and spermatocyte translocation mechanisms that incorporate tubulobulbar complexes into their designs.
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Affiliation(s)
- A Wayne Vogl
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC Canada V6T 1Z3.
| | - Min Du
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC Canada V6T 1Z3.
| | - Xue Ying Wang
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC Canada V6T 1Z3.
| | - J'Nelle S Young
- Department of Radiology, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA. J'
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Aristaeus de Asis M, Pires M, Lyon K, Vogl AW. A network of spectrin and plectin surrounds the actin cuffs of apical tubulobulbar complexes in the rat. SPERMATOGENESIS 2013; 3:e25733. [PMID: 24381803 PMCID: PMC3861171 DOI: 10.4161/spmg.25733] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 11/19/2022]
Abstract
Tubulobulbar complexes (TBCs) are actin-related endocytic structures that internalize intercellular junctions in the seminiferous epithelium. The structures consist of elongate tubular projections of the attached plasma membranes of two adjacent cells that project into Sertoli cells. This double membrane core is cuffed by a dentritic actin network and is capped at its end by a clathrin-coated pit. Here we explore the possibility that elements of the spectrin cytoskeleton are associated with clusters of tubulobulbar complexes that develop at adhesion junctions between late spermatids and Sertoli cells at the apex of the epithelium, and extend what is known about the distribution of plectin at the sites. Cryo-sections of perfusion-fixed testes and apical processes of Sertoli cells mechanically dissociated from perfusion-fixed testes were probed for spectrin, EPB41, and actin and analyzed using conventional fluorescence microscopy and confocal microscopy. Data sets from confocal microscopy were analyzed further in three-dimensional reconstructions using computer software. Additional apical Sertoli cell processes were probed for plectin and analyzed using conventional fluorescence microscopy. Antibodies generated against elements of the spectrin cytoskeleton react with material around and between the actin cuffs of tubulobulbar complexes, but appear excluded from the actin cuffs themselves. A similar staining pattern occurs with a probe for plectin. Immunoelectron microscopy confirmed the staining patterns observed by fluourescence microscopy. Based on our results, we suggest that a network of spectrin and plectin forms a scaffold around tubulobulbar complexes that may provide support for the actin network that cuffs each complex and also link adjacent complexes together.
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Affiliation(s)
| | - Manuel Pires
- Faculte des Sciences Fondamentales et Appliquees; Universite de Poitiers; Poitiers, France
| | - Kevin Lyon
- Department of Cellular and Physiological Sciences; Faculty of Medicine; University of British Columbia; BC Canada
| | - A Wayne Vogl
- Department of Cellular and Physiological Sciences; Faculty of Medicine; University of British Columbia; BC Canada
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Qian X, Cheng YH, Mruk DD, Cheng CY. Breast cancer resistance protein (Bcrp) and the testis--an unexpected turn of events. Asian J Androl 2013; 15:455-60. [PMID: 23665760 DOI: 10.1038/aja.2013.24] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 02/06/2013] [Accepted: 03/06/2013] [Indexed: 01/28/2023] Open
Abstract
Breast cancer resistance protein (Bcrp) is an ATP-dependent efflux drug transporter. It has a diverse spectrum of hydrophilic and hydrophobic substrates ranging from anticancer, antiviral and antihypertensive drugs, to organic anions, antibiotics, phytoestrogens (e.g., genistein, daidzein, coumestrol), xenoestrogens and steroids (e.g., dehydroepiandrosterone sulfate). Bcrp is an integral membrane protein in cancer and normal cells within multiple organs (e.g., brain, placenta, intestine and testis) that maintains cellular homeostasis by extruding drugs and harmful substances from the inside of cells. In the brain, Bcrp is a major component of the blood-brain barrier located on endothelial cells near tight junctions (TJs). However, Bcrp is absent at the Sertoli cell blood-testis barrier (BTB); instead, it is localized almost exclusively to the endothelial TJ in microvessels in the interstitium and the peritubular myoid cells in the tunica propria. Recent studies have shown that Bcrp is also expressed stage specifically and spatiotemporally by Sertoli and germ cells in the seminiferous epithelium of rat testes, limited only to a testis-specific cell adhesion ultrastructure known as the apical ectoplasmic specialisation (ES) in stage VI-early VIII tubules. These findings suggest that Bcrp is equipped by late spermatids and Sertoli cells to protect late-stage spermatids completing spermiogenesis. Furthermore, Bcrp was found to be associated with F (filamentous)-actin and several actin regulatory proteins at the apical ES and might be involved in the organisation of actin filaments at the apical ES in stage VII-VIII tubules. These findings will be carefully evaluated in this brief review.
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Affiliation(s)
- Xiaojing Qian
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY 10065, USA
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Qian X, Mruk DD, Cheng CY. Rai14 (retinoic acid induced protein 14) is involved in regulating f-actin dynamics at the ectoplasmic specialization in the rat testis*. PLoS One 2013; 8:e60656. [PMID: 23565266 PMCID: PMC3614988 DOI: 10.1371/journal.pone.0060656] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 03/01/2013] [Indexed: 01/31/2023] Open
Abstract
Rai14 (retinoic acid induced protein 14) is an actin binding protein first identified in the liver, highly expressed in the placenta, the testis, and the eye. In the course of studying actin binding proteins that regulate the organization of actin filament bundles in the ectoplasmic specialization (ES), a testis-specific actin-rich adherens junction (AJ) type, Rai14 was shown to be one of the regulatory proteins at the ES. In the rat testis, Rai14 was found to be expressed by Sertoli and germ cells, structurally associated with actin and an actin cross-linking protein palladin. Its expression was the highest at the ES in the seminiferous epithelium of adult rat testes, most notably at the apical ES at the Sertoli-spermatid interface, and expressed stage-specifically during the epithelial cycle in stage VII-VIII tubules. However, Rai14 was also found at the basal ES near the basement membrane, associated with the blood-testis barrier (BTB) in stage VIII-IX tubules. A knockdown of Rai14 in Sertoli cells cultured in vitro by RNAi was found to perturb the Sertoli cell tight junction-permeability function in vitro, mediated by a disruption of F-actin, which in turn led to protein mis-localization at the Sertoli cell BTB. When Rai14 in the testis in vivo was knockdown by RNAi, defects in spermatid polarity and adhesion, as well as spermatid transport were noted mediated via changes in F-actin organization and mis-localization of proteins at the apical ES. In short, Rai14 is involved in the re-organization of actin filaments in Sertoli cells during the epithelial cycle, participating in conferring spermatid polarity and cell adhesion in the testis.
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Affiliation(s)
- Xiaojing Qian
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, United States of America
- Department of Anatomy, Histology and Embryology, School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Dolores D. Mruk
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - C. Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, United States of America
- * E-mail:
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Du M, Young J, De Asis M, Cipollone J, Roskelley C, Takai Y, Nicholls PK, Stanton PG, Deng W, Finlay BB, Vogl AW. A novel subcellular machine contributes to basal junction remodeling in the seminiferous epithelium. Biol Reprod 2013; 88:60. [PMID: 23303684 DOI: 10.1095/biolreprod.112.104851] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tubulobulbar complexes are cytoskeleton-related membrane structures that develop at sites of intercellular attachment in mammalian seminiferous epithelium. At apical junctions between Sertoli cells and spermatids, the structures internalize adhesion junctions and are a component of the sperm release mechanism. Here we explore the possibility that tubulobulbar complexes that form at the blood-testis barrier are subcellular machines that internalize basal junction complexes. Using electron microscopy, we confirmed that morphologically identifiable tight and gap junctions are present in basal tubulobulbar complexes in rats. In addition, immunological probes for claudin-11 (CLDN11), connexin-43 (GJA1), and nectin-2 (PVRL2) react with linear structures at the light level that we interpret as tubulobulbar complexes, and probes for early endosome antigen 1 (EEA1) and Rab5 (RAB5A) react in similar locations. Significantly, fluorescence patterns for actin and claudin-11 indicate that the amount of junction present is dramatically reduced over the time period that tubulobulbar complexes are known to be most prevalent during spermatogenesis. We also demonstrated, using electron microscopy and fluorescence microscopy, that tubulobulbar complexes develop at basal junctions in primary cultures of Sertoli cells and that like their in vivo counterparts, the structures contain junction proteins. We use this culture system together with transfection techniques to show that junction proteins from one transfected cell occur in structures that project into adjacent nontransfected cells as predicted by the junction internalization hypothesis. On the basis of our findings, we present a new model for basal junction remodeling as it relates to spermatocyte translocation in the seminiferous epithelium.
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Affiliation(s)
- Min Du
- Department of Cellular and Physiological Sciences, Faculty of Medicine, Life Sciences Centre, The University of British Columbia, Vancouver, British Columbia, Canada
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Su W, Mruk DD, Cheng CY. Regulation of actin dynamics and protein trafficking during spermatogenesis--insights into a complex process. Crit Rev Biochem Mol Biol 2013; 48:153-72. [PMID: 23339542 DOI: 10.3109/10409238.2012.758084] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the mammalian testis, extensive restructuring takes place across the seminiferous epithelium at the Sertoli-Sertoli and Sertoli-germ cell interface during the epithelial cycle of spermatogenesis, which is important to facilitate changes in the cell shape and morphology of developing germ cells. However, precise communications also take place at the cell junctions to coordinate the discrete events pertinent to spermatogenesis, namely spermatogonial renewal via mitosis, cell cycle progression and meiosis, spermiogenesis and spermiation. It is obvious that these cellular events are intimately related to the underlying actin-based cytoskeleton which is being used by different cell junctions for their attachment. However, little is known on the biology and regulation of this cytoskeleton, in particular its possible involvement in endocytic vesicle-mediated trafficking during spermatogenesis, which in turn affects cell adhesive function and communication at the cell-cell interface. Studies in other epithelia in recent years have shed insightful information on the intimate involvement of actin dynamics and protein trafficking in regulating cell adhesion and communications. The goal of this critical review is to provide an updated assessment of the latest findings in the field on how these complex processes are being regulated during spermatogenesis. We also provide a working model based on the latest findings in the field including our laboratory to provide our thoughts on an apparent complicated subject, which also serves as the framework for investigators in the field. It is obvious that this model will be rapidly updated when more data are available in future years.
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Affiliation(s)
- Wenhui Su
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY 10065, 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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Vogl AW, Young JS, Du M. New insights into roles of tubulobulbar complexes in sperm release and turnover of blood-testis barrier. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 303:319-55. [PMID: 23445814 DOI: 10.1016/b978-0-12-407697-6.00008-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Tubulobulbar complexes are actin-filament-related structures that form at intercellular junctions in the seminiferous epithelium of mammalian testis. The structures occur both at adhesion junctions between Sertoli cells and the maturing spermatids in apical regions of the epithelium, and at junction complexes between neighboring Sertoli cells near the base of the epithelium. Here, we review the general morphology and molecular composition of tubulobulbar complexes, and also include a description of tubulobulbar complex structure in the human seminiferous epithelium. Although tubulobulbar complexes are unique to the seminiferous epithelium, they have the molecular signature of clathrin-based endocytosis machinery present generally in cells. We review the evidence that tubulobulbar complexes internalize intact intercellular junctions and are significant components of the sperm-release mechanism and the process by which spermatocytes translocate from basal to adluminal compartments of the epithelium.
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Affiliation(s)
- A Wayne Vogl
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.
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Xiao X, Mruk DD, Cheng FL, Cheng CY. C-Src and c-Yes are two unlikely partners of spermatogenesis and their roles in blood-testis barrier dynamics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 763:295-317. [PMID: 23397631 DOI: 10.1007/978-1-4614-4711-5_15] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Src family kinases (SFKs), in particular c-Src and c-Yes, are nonreceptor protein tyrosine kinases that mediate integrin signaling at focal adhesion complex at the cell-extracellular matrix interface to regulate cell adhesion, cell cycle progression, cell survival, proliferation and differentiation, most notably in cancer cells during tumorigenesis and metastasis. Interestingly, recent studies have shown that these two proto-oncogenes are integrated components of the stem cell niche and the cell-cell actin-based anchoring junction known as ectoplasmic specialization (ES) at the: (1) Sertoli cell-spermatid interface known as apical ES and (2) Sertoli-Sertoli cell interface known as basal ES which together with tight junctions (TJ), gap junctions and desmosomes constitute the blood-testis barrier (BTB). At the stem cell niche, these SFKs regulate spermatogonial stem cell (SSC) renewal to maintain the proper population of SSC/spermatogonia for spermatogenesis. At the apical ES and the BTB, c-Src and c-Yes confer cell adhesion either by maintaining the proper phosphorylation status of integral membrane proteins at the site which in turn regulates protein-protein interactions between integral membrane proteins and their adaptors, or by facilitating androgen action on spermatogenesis via a nongenomic pathway which also modulates cell adhesion in the seminiferous epithelium. Herein, we critically evaluate recent findings in the field regarding the roles of these two unlikely partners of spermatogenesis. We also propose a hypothetical model on the mechanistic functions of c-Src and c-Yes in spermatogenesis so that functional experiments can be designed in future studies.
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Affiliation(s)
- Xiang Xiao
- Center for Biomedical Research, Population Council, New York New York, USA
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50
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Wong EWP, Lee WM, Cheng CY. Secreted Frizzled-related protein 1 (sFRP1) regulates spermatid adhesion in the testis via dephosphorylation of focal adhesion kinase and the nectin-3 adhesion protein complex. FASEB J 2012; 27:464-77. [PMID: 23073828 DOI: 10.1096/fj.12-212514] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Development of spermatozoa in adult mammalian testis during spermatogenesis involves extensive cell migration and differentiation. Spermatogonia that reside at the basal compartment of the seminiferous epithelium differentiate into more advanced germ cell types that migrate toward the apical compartment until elongated spermatids are released into the tubule lumen during spermiation. Apical ectoplasmic specialization (ES; a testis-specific anchoring junction) is the only cell junction that anchors and maintains the polarity of elongating/elongated spermatids (step 8-19 spermatids) in the epithelium. Little is known regarding the signaling pathways that trigger the disassembly of the apical ES at spermiation. Here, we show that secreted Frizzled-related protein 1 (sFRP1), a putative tumor suppressor gene that is frequently down-regulated in multiple carcinomas, is a crucial regulatory protein for spermiation. The expression of sFRP1 is tightly regulated in adult rat testis to control spermatid adhesion and sperm release at spermiation. Down-regulation of sFRP1 during testicular development was found to coincide with the onset of the first wave of spermiation at approximately age 45 d postpartum, implying that sFRP1 might be correlated with elongated spermatid adhesion conferred by the apical ES before spermiation. Indeed, administration of sFRP1 recombinant protein to the testis in vivo delayed spermiation, which was accompanied by down-regulation of phosphorylated (p)-focal adhesion kinase (FAK)-Tyr(397) and retention of nectin-3 adhesion protein at the apical ES. To further investigate the functional relationship between p-FAK-Tyr(397) and localization of nectin-3, we overexpressed sFRP1 using lentiviral vectors in the Sertoli-germ cell coculture system. Consistent with the in vivo findings, overexpression of sFRP1 induced down-regulation of p-FAK-Tyr(397), leading to a decline in phosphorylation of nectin-3. In summary, this report highlights the critical role of sFRP1 in regulating spermiation via its effects on the FAK signaling and retention of nectin-3 adhesion complex at the apical ES.
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Affiliation(s)
- Elissa W P Wong
- Center for Biomedical Research, Population Council, Rockefeller University, New York, New York 10065, USA
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