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Tourmente M, Sansegundo E, Rial E, Roldan ERS. Bioenergetic changes in response to sperm capacitation and two-way metabolic compensation in a new murine model. Cell Mol Life Sci 2023; 80:11. [PMID: 36534181 PMCID: PMC9763147 DOI: 10.1007/s00018-022-04652-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/29/2022] [Accepted: 11/24/2022] [Indexed: 12/23/2022]
Abstract
The acquisition of fertilizing ability by mammalian spermatozoa, known as "capacitation," includes processes that depend on particular metabolic pathways. This has led to the hypothesis that ATP demands might differ between capacitated and non-capacitated cells. Mouse sperm can produce ATP via OXPHOS and aerobic glycolysis, an advantageous characteristic considering that these cells have to function in the complex and variable environment of the female reproductive tract. Nonetheless, despite evidence showing that both metabolic pathways play a role in events associated with mouse sperm capacitation, there is contradictory evidence regarding changes promoted by capacitation in this species. In addition, the vast majority of studies regarding murine sperm metabolism use Mus musculus laboratory strains as model, thus neglecting the wide diversity of sperm traits of other species of Mus. Focus on closely related species with distinct evolutionary histories, which may be the result of different selective pressures, could shed light on diversity of metabolic processes. Here, we analyzed variations in sperm bioenergetics associated with capacitation in spermatozoa of the steppe mouse, Mus spicilegus, a species with high sperm performance. Furthermore, we compared sperm metabolic traits of this species with similar traits previously characterized in M. musculus. We found that the metabolism of M. spicilegus sperm responded to capacitation in a manner similar to that of M. musculus sperm. However, M. spicilegus sperm showed distinct metabolic features, including the ability to perform cross-pathway metabolic compensation in response to either respiratory or glycolytic inhibition, thus revealing a delicate fine-tuning of its metabolic capacities.
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Affiliation(s)
- Maximiliano Tourmente
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain.
- Centro de Biología Celular y Molecular, Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN - UNC), Universidad Nacional de Córdoba, Córdoba, Argentina.
- Instituto de Investigaciones Biológicas y Tecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas (IIByT - CONICET, UNC), Córdoba, Argentina.
| | - Ester Sansegundo
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Eduardo Rial
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Eduardo R S Roldan
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain.
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2
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Tourmente M, Sansegundo E, Rial E, Roldan ERS. Capacitation promotes a shift in energy metabolism in murine sperm. Front Cell Dev Biol 2022; 10:950979. [PMID: 36081906 PMCID: PMC9445201 DOI: 10.3389/fcell.2022.950979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
In mammals, sperm acquire fertilization ability after a series of physiological and biochemical changes, collectively known as capacitation, that occur inside the female reproductive tract. In addition to other requirements, sperm bioenergetic metabolism has been identified as a fundamental component in the acquisition of capacitation. Mammalian sperm produce ATP through two main metabolic processes, oxidative phosphorylation (OXPHOS) and aerobic glycolysis that are localized to two different flagellar compartments, the midpiece, and the principal piece, respectively. In mouse sperm, the occurrence of many events associated with capacitation relies on the activity of these two energy-producing pathways, leading to the hypothesis that some of these events may impose changes in sperm energetic demands. In the present study, we used extracellular flux analysis to evaluate changes in glycolytic and respiratory parameters of murine sperm that occur as a consequence of capacitation. Furthermore, we examined whether these variations affect sperm ATP sustainability. Our results show that capacitation promotes a shift in the usage ratio of the two main metabolic pathways, from oxidative to glycolytic. However, this metabolic rewiring does not seem to affect the rate at which the sperm consume ATP. We conclude that the probable function of the metabolic switch is to increase the ATP supply in the distal flagellar regions, thus sustaining the energetic demands that arise from capacitation.
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Affiliation(s)
- Maximiliano Tourmente
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
- Centro de Biología Celular y Molecular, Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN—UNC), Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Investigaciones Biológicas y Tecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas (IIByT—CONICET, UNC), Córdoba, Argentina
- *Correspondence: Maximiliano Tourmente, ; Eduardo R. S. Roldan,
| | - Ester Sansegundo
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Eduardo Rial
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Eduardo R. S. Roldan
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
- *Correspondence: Maximiliano Tourmente, ; Eduardo R. S. Roldan,
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3
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Gao DD, Lan CF, Cao XN, Chen L, Lei TL, Peng L, Xu JW, Qiu ZE, Wang LL, Sun Q, Huang ZY, Zhu YX, Zhou WL, Zhang YL. G protein-coupled estrogen receptor promotes acrosome reaction via regulation of Ca2+ signaling in mouse sperm. Biol Reprod 2022; 107:1026-1034. [PMID: 35774023 DOI: 10.1093/biolre/ioac136] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/18/2022] [Accepted: 06/22/2022] [Indexed: 11/13/2022] Open
Abstract
G protein-coupled estrogen receptor (GPER), a seven-transmembrane G protein-coupled receptor, mediates the rapid pre-genomic signaling actions of estrogen and derivatives thereof. The expression of GPER is extensive in mammal male reproductive system. However, the functional role of GPER in mouse sperm has not yet been well recognized. This study revealed that GPER was expressed at the acrosome and the mid-flagellum of the mouse sperm. The endogenous GPER ligand 17β-estradiol and the selective GPER agonist G1 increased intracellular Ca2+ concentration ([Ca2+]i) in mouse sperm, which could be abolished by G15, an antagonist of GPER. In addition, the G1-stimulated Ca2+ response was attenuated by interference with the phospholipase C (PLC) signaling pathways or by blocking the cation sperm channel (CatSper). Chlortetracycline staining assay showed that the activation of GPER increased the incidence of acrosome-reacted sperm. Conclusively, GPER was located at the acrosome and mid-flagellum of the mouse sperm. Activation of GPER triggered the elevation of [Ca2+]i through PLC-dependent Ca2+ mobilization and CatSper-mediated Ca2+ influx, which promoted the acrosome reaction in mouse sperm.
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Affiliation(s)
- Dong-Dong Gao
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China.,Guangdong Provincial Key Laboratory of Physical Activity and Health Promotion, Scientific Research Center, Guangzhou Sport University, Guangzhou, P.R. China
| | - Chong-Feng Lan
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Xiao-Nian Cao
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Lei Chen
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Tian-Lun Lei
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Lei Peng
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Jia-Wen Xu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Zhuo-Er Qiu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Long-Long Wang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Qing Sun
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Zi-Yang Huang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Yun-Xin Zhu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Wen-Liang Zhou
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
| | - Yi-Lin Zhang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China
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4
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Morcillo i Soler P, Hidalgo C, Fekete Z, Zalanyi L, Khalil ISM, Yeste M, Magdanz V. Bundle formation of sperm: Influence of environmental factors. Front Endocrinol (Lausanne) 2022; 13:957684. [PMID: 36299459 PMCID: PMC9591104 DOI: 10.3389/fendo.2022.957684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 09/22/2022] [Indexed: 11/13/2022] Open
Abstract
Cooperative behaviour of sperm is one of the mechanisms that plays a role in sperm competition. It has been observed in several species that spermatozoa interact with each other to form agglomerates or bundles. In this study, we investigate the effect of physical and biochemical factors that will most likely promote bundle formation in bull sperm. These factors include fluid viscosity, swim-up process, post-thaw incubation time and media additives which promote capacitation. While viscosity does not seem to influence the degree of sperm bundling, swim-up, post-thaw migration time and suppressed capacitation increase the occurrence of sperm bundles. This leads to the conclusion that sperm bundling is a result of hydrodynamic and adhesive interactions between the cells which occurs frequently during prolonged incubation times.
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Affiliation(s)
| | - Carlos Hidalgo
- Centro de Biotecnológia Animal SERIDA-DEVA-GIJON, Gijón, Spain
| | - Zoltán Fekete
- ONGO Vettech Ltd., Martonvásár, Hungary
- Faculty of Information Technology & Bionics, Pazmany Peter Catholic University, Budapest, Hungary
| | - Laszlo Zalanyi
- ONGO Vettech Ltd., Martonvásár, Hungary
- Department of Computational Sciences, Wigner Research Centre for Physics, Budapest, Hungary
| | - Islam S. M. Khalil
- Department of Biomechanical Engineering, University of Twente, Enschede, Netherlands
| | - Marc Yeste
- University of Girona, Girona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Veronika Magdanz
- Smart Nanobiodevices Group, Institute for Bioengineering of Catalonia, Barcelona, Spain
- Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada
- *Correspondence: Veronika Magdanz,
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5
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Upadhyay VR, Ramesh V, Dewry RK, Kumar G, Raval K, Patoliya P. Implications of cryopreservation on structural and functional attributes of bovine spermatozoa: An overview. Andrologia 2021; 53:e14154. [PMID: 34143907 DOI: 10.1111/and.14154] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/12/2021] [Accepted: 06/03/2021] [Indexed: 01/31/2023] Open
Abstract
Sperm cryopreservation is an important adjunct to assisted reproduction techniques (ART) for improving the reproductive efficiency of dairy cattle and buffaloes. Improved understanding of mechanisms and challenges of bovine semen cryopreservation is vital for artificial insemination on a commercial basis. Although cryopreservation of bovine spermatozoa is widely practiced and advanced beyond that of other species, there are still major gaps in the knowledge and technology. Upon cryopreservation, disruption of spermatozoal plasma membrane configuration due to alterations in metabolic pathways, enzymes and antioxidants activity add to lower efficiency with loss of sperm longevity and fertilising ability. Therefore, the effective amalgamation of cryo-variables like ambient temperature, cooling and thawing rates, nucleation temperature, type and concentration of the cryoprotectant, seminal plasma composition, free radicals and antioxidant status are required to optimise cryopreservation. Novel strategies like supplementation of cholesterol-loaded cyclodextrins (CLC), nanovesicles, osteopontin, antioxidants, etc., in an extender and recent techniques like nano-purification and modified packaging have to be optimised to ameliorate the cryodamage. This article is intended to describe the basic facts about the sperm cryopreservation process in bovine and the associated biochemical, biophysical, ultra-structural, molecular and functional alterations.
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Affiliation(s)
| | - Vikram Ramesh
- Animal Reproduction and Gynecology, ICAR-National Research Centre on Mithun, Medziphema, India
| | - Raju Kumar Dewry
- Artificial Breeding Research Centre, ICAR-National Dairy Research Institute, Karnal, India
| | - Gaurav Kumar
- Division of Animal Physiology, ICAR-National Dairy Research Institute, Karnal, India
| | - Kathan Raval
- Artificial Breeding Research Centre, ICAR-National Dairy Research Institute, Karnal, India
| | - Priyanka Patoliya
- Division of Livestock Production Management, ICAR-National Dairy Research Institute, Karnal, India
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6
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Balbach M, Hamzeh H, Jikeli JF, Brenker C, Schiffer C, Hansen JN, Neugebauer P, Trötschel C, Jovine L, Han L, Florman HM, Kaupp UB, Strünker T, Wachten D. Molecular Mechanism Underlying the Action of Zona-pellucida Glycoproteins on Mouse Sperm. Front Cell Dev Biol 2020; 8:572735. [PMID: 32984353 PMCID: PMC7487327 DOI: 10.3389/fcell.2020.572735] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/12/2020] [Indexed: 01/10/2023] Open
Abstract
Mammalian oocytes are enveloped by the zona pellucida (ZP), an extracellular matrix of glycoproteins. In sperm, stimulation with ZP proteins evokes a rapid Ca2+ influx via the sperm-specific, pH-sensitive Ca2+ channel CatSper. However, the physiological role and molecular mechanisms underlying ZP-dependent activation of CatSper are unknown. Here, we delineate the sequence of ZP-signaling events in mouse sperm. We show that ZP proteins evoke a rapid intracellular pHi increase that rests predominantly on Na+/H+ exchange by NHA1 and requires cAMP synthesis by the soluble adenylyl cyclase sAC as well as a sufficiently negative membrane potential set by the spem-specific K+ channel Slo3. The alkaline-activated CatSper channel translates the ZP-induced pHi increase into a Ca2+ response. Our findings reveal the molecular components underlying ZP action on mouse sperm, opening up new avenues for understanding the basic principles of sperm function and, thereby, mammalian fertilization.
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Affiliation(s)
- Melanie Balbach
- Center of Advanced European Studies and Research, Department of Molecular Sensory Systems, Bonn, Germany
| | - Hussein Hamzeh
- Center of Advanced European Studies and Research, Department of Molecular Sensory Systems, Bonn, Germany
| | - Jan F Jikeli
- Institute of Innate Immunity, Department of Biophysical Imaging, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christoph Brenker
- Center of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Christian Schiffer
- Center of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Jan N Hansen
- Institute of Innate Immunity, Department of Biophysical Imaging, Medical Faculty, University of Bonn, Bonn, Germany
| | - Pia Neugebauer
- Institute of Innate Immunity, Department of Biophysical Imaging, Medical Faculty, University of Bonn, Bonn, Germany
| | | | - Luca Jovine
- Department of Biosciences and Nutrition, Karolinska Institutet, Solna, Sweden
| | - Ling Han
- Department of Biosciences and Nutrition, Karolinska Institutet, Solna, Sweden
| | - Harvey M Florman
- Department of Obstetrics and Gynecology, University of Massachusetts Medical School Worcester, Worcester, MA, United States
| | - U Benjamin Kaupp
- Center of Advanced European Studies and Research, Department of Molecular Sensory Systems, Bonn, Germany.,Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
| | - Timo Strünker
- Center of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Dagmar Wachten
- Institute of Innate Immunity, Department of Biophysical Imaging, Medical Faculty, University of Bonn, Bonn, Germany
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7
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Jin SK, Yang WX. Factors and pathways involved in capacitation: how are they regulated? Oncotarget 2018; 8:3600-3627. [PMID: 27690295 PMCID: PMC5356907 DOI: 10.18632/oncotarget.12274] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/23/2016] [Indexed: 01/07/2023] Open
Abstract
In mammals, fertilization occurs via a comprehensive progression of events. Freshly ejaculated sperm have yet to acquire progressive motility or fertilization ability. They must first undergo a series of biochemical and physiological changes, collectively known as capacitation. Capacitation is a significant prerequisite to fertilization. During the process of capacitation, changes in membrane properties, intracellular ion concentration and the activities of enzymes, together with other protein modifications, induce multiple signaling events and pathways in defined media in vitro or in the female reproductive tract in vivo. These, in turn, stimulate the acrosome reaction and prepare spermatozoa for penetration of the egg zona pellucida prior to fertilization. In the present review, we conclude all mainstream factors and pathways regulate capacitation and highlight their crosstalk. We also summarize the relationship between capacitation and assisted reproductive technology or human disease. In the end, we sum up the open questions and future avenues in this field.
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Affiliation(s)
- Shi-Kai Jin
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
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8
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Sun XH, Zhu YY, Wang L, Liu HL, Ling Y, Li ZL, Sun LB. The Catsper channel and its roles in male fertility: a systematic review. Reprod Biol Endocrinol 2017; 15:65. [PMID: 28810916 PMCID: PMC5558725 DOI: 10.1186/s12958-017-0281-2] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 08/03/2017] [Indexed: 12/22/2022] Open
Abstract
The Catsper channel is a sperm-specific, Ca2+-permeable, pH-dependent, and low voltage-dependent channel that is essential for the hyperactivity of sperm flagellum, chemotaxis towards the egg, capacitation and acrosome reaction. All of these physiological events require calcium entry into sperm cells. Remarkably, Catsper genes are exclusively expressed in the testis during spermatogenesis, and are sensitive to ion channel-induced pH change, such as NHEs, Ca2+ATPase, K+ channel, Hv1 channel and HCO3- transporters. Furthermore, the Catsper channel is regulated by some physiological stimulants, such as progesterone, cyclic nucleotides (e.g., cAMP, cGMP), zona pellucida (ZP) glycoproteins and bovine serum albumin (BSA). All of these factors normally stimulate Ca2+ entry into sperm through the Catsper channel. In addition, the Catsper channel may be a potential target for male infertility treatment or contraception. This review will focus on the structure, functions, regulation mechanisms and medicinal targets of the Catsper channel.
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Affiliation(s)
- Xiang-hong Sun
- grid.412521.1Department of pharmacy, the affiliated hospital of Qingdao University Medical College, Qingdao, 266555 China
| | - Ying-ying Zhu
- 0000 0001 0455 0905grid.410645.2Department of pharmacy, College of pharmacy of Qingdao University, Qingdao, China
| | - Lin Wang
- grid.412521.1Department of clinical laboratory, the affiliated hospital of Qingdao University Medical College, Qingdao, China
| | - Hong-ling Liu
- grid.412521.1Department of pharmacy, the affiliated hospital of Qingdao University Medical College, Qingdao, 266555 China
| | - Yong Ling
- grid.412521.1Department of pharmacy, the affiliated hospital of Qingdao University Medical College, Qingdao, 266555 China
| | - Zong-li Li
- grid.412521.1Department of pharmacy, the affiliated hospital of Qingdao University Medical College, Qingdao, 266555 China
| | - Li-bo Sun
- grid.412521.1Department of pharmacy, the affiliated hospital of Qingdao University Medical College, Qingdao, 266555 China
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9
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Harikrishna P, Shende AM, Reena KK, Thomas J, Bhure SK. Purification of Regucalcin from the Seminal Vesicular Fluid: A Calcium Binding Multi-Functional Protein. Protein J 2016; 35:310-7. [DOI: 10.1007/s10930-016-9674-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Calcium influx and male fertility in the context of the sperm proteome: an update. BIOMED RESEARCH INTERNATIONAL 2014; 2014:841615. [PMID: 24877140 PMCID: PMC4022195 DOI: 10.1155/2014/841615] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 01/14/2014] [Indexed: 01/06/2023]
Abstract
Freshly ejaculated spermatozoa are incapable or poorly capable of fertilizing an oocyte. The fertilization aptness of spermatozoa depends on the appropriate and time-dependent acquisition of hyperactivation, chemotaxis, capacitation, and the acrosome reaction, where calcium (Ca2+) is extensively involved in almost every step. A literature review showed that several ion channel proteins are likely responsible for regulation of the Ca2+ uptake in spermatozoa. Therefore, manipulation of the functions of channel proteins is closely related to Ca2+ influx, ultimately affecting male fertility. Recently, it has been shown that, together with different physiological stimuli, protein-protein interaction also modifies the Ca2+ influx mechanism in spermatozoa. Modern proteomic analyses have identified several sperm proteins, and, therefore, these findings might provide further insight into understanding the Ca2+ influx, protein functions, and regulation of fertility. The objective of this review was to synthesize the published findings on the Ca2+ influx mechanism in mammalian spermatozoa and its implications for the regulation of male fertility in the context of sperm proteins. Finally, Pathway Studio (9.0) was used to catalog the sperm proteins that regulate the Ca2+ influx signaling by using the information available from the PubMed database following a MedScan Reader (5.0) search.
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11
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Nagdas SK, Buchanan T, McCaskill S, Mackey J, Alvarez GE, Raychoudhury S. Isolation of a calcium-binding protein of the acrosomal membrane of bovine spermatozoa. Int J Biochem Cell Biol 2013; 45:876-84. [PMID: 23376657 DOI: 10.1016/j.biocel.2013.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/18/2013] [Accepted: 01/22/2013] [Indexed: 01/11/2023]
Abstract
The mammalian sperm acrosome reaction is a calcium-dependent exocytotic event characterized by extensive fusion between the plasma and the outer acrosomal membrane. The mechanisms by which elevation of cytosolic calcium initiates the membrane fusion process are not understood and the present study was undertaken to identify calcium-binding proteins in the acrosomal membrane (AM) of bovine spermatozoa. Sperm heads, purified from sonicated spermatozoa, were used to isolate an acrosomal membrane-enriched fraction on Percoll density gradients. Using SDS-PAGE and a (45)Ca(2+)-blot overlay assay, calcium-binding proteins of 64, 45, 43, and 39kDa were identified in the AM enriched fraction. Phase separation analysis with Triton X-114 identified the 64kDa polypeptide as an integral membrane protein. The 64kDa polypeptide was purified and utilized to prepare a polyclonal antiserum. Both light and electron microscopic immunocytochemistry demonstrated that the protein was distributed throughout all domains of the acrosomal membrane. These results identify a 64kDa calcium-binding integral membrane protein of the mammalian acrosome. Its potential function in calcium-dependent membrane fusion events of the acrosome reaction and in fertilization is discussed.
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Affiliation(s)
- Subir K Nagdas
- Department of Chemistry and Physics, Fayetteville State University, Fayetteville, NC 28301, USA.
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12
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Singh VK, Atreja SK, Kumar R, Chhillar S, Singh AK. Assessment of intracellular Ca2+, cAMP and 1,2-diacylglycerol in cryopreserved buffalo (Bubalus bubalis) spermatozoa on supplementation of taurine and trehalose in the extender. Reprod Domest Anim 2011; 47:584-90. [PMID: 21988572 DOI: 10.1111/j.1439-0531.2011.01922.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In mammalian spermatozoa, intracellular calcium plays a major role in sperm functions like motility and capacitation. Cryopreservation-induced modifications to sperm membrane result in an influx of intracellular calcium affecting calcium-dependent intracellular signalling pathways. Intracellular calcium activates adenyl cyclase to produce cAMP that activates phospholipase A(2) (PLA(2) ) and phospholipase C (PLC) generating lysophosphatidyl choline, 1,2-diacylglycerol (DAG) and IP(3) , acting as intracellular secondary messengers required for sperm capacitation. Present study was designed to determine levels of intracellular calcium, cAMP and DAG in fresh and frozen-thawed buffalo spermatozoa cryopreserved in the presence and absence of taurine or trehalose. A total number of nine ejaculates from three randomly chosen buffalo bulls were cryopreserved in Tris-based egg yolk extender and thawed in warm water at 37°C. The cAMP was measured by enzyme immuno assay, and intracellular calcium was quantified using fluorescent dye FURA 2-AM. Total lipid was extracted from spermatozoa, and DAG was estimated using thin layer chromatography followed by spectrophotometric analysis. Intracellular calcium, cAMP and DAG levels in spermatozoa were significantly (p < 0.01) increased following cryopreservation as compared to fresh ejaculate. Addition of taurine or trehalose to the freezing medium significantly decreased (p < 0.01) the levels of intracellular calcium and cAMP in frozen-thawed spermatozoa. 1,2-diacylglycerol content was also decreased significantly (p < 0.01) in spermatozoa cryopreserved in presence of additives. Moreover, significant (p < 0.01) improvement in post-thaw motility, viability and membrane integrity of spermatozoa on addition of taurine or trehalose clearly indicated the reduced level of capacitation-like changes in buffalo spermatozoa.
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Affiliation(s)
- V K Singh
- Reproductive Biochemistry Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, Haryana, India
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13
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Abstract
During mammalian fertilisation, the zona pellucida (ZP) matrix surrounding the oocyte is responsible for the binding of the spermatozoa to the oocyte and induction of the acrosome reaction (AR) in the ZP-bound spermatozoon. The AR is crucial for the penetration of the ZP matrix by spermatozoa. The ZP matrix in mice is composed of three glycoproteins designated ZP1, ZP2 and ZP3, whereas in humans, it is composed of four (ZP1, ZP2, ZP3 and ZP4). ZP3 acts as the putative primary sperm receptor and is responsible for AR induction in mice, whereas in humans (in addition to ZP3), ZP1 and ZP4 also induce the AR. The ability of ZP3 to induce the AR resides in its C-terminal fragment. O-linked glycans are critical for the murine ZP3-mediated AR. However, N-linked glycans of human ZP1, ZP3 and ZP4 have important roles in the induction of the AR. Studies with pharmacological inhibitors showed that the ZP3-induced AR involves the activation of the G(i)-coupled receptor pathway, whereas ZP1- and ZP4-mediated ARs are independent of this pathway. The ZP3-induced AR involves the activation of T-type voltage-operated calcium channels (VOCCs), whereas ZP1- and ZP4-induced ARs involve both T- and L-type VOCCs. To conclude, in mice, ZP3 is primarily responsible for the binding of capacitated spermatozoa to the ZP matrix and induction of the AR, whereas in humans (in addition to ZP3), ZP1 and ZP4 also participate in these stages of fertilisation.
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Ren D, Xia J. Calcium signaling through CatSper channels in mammalian fertilization. Physiology (Bethesda) 2010; 25:165-75. [PMID: 20551230 DOI: 10.1152/physiol.00049.2009] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The molecular mechanisms underlying Ca(2+) entry into sperm are now much more well defined thanks to direct recordings of mature sperm cells. This article reviews the function of a sperm-specific ion channel, CatSper. CatSpers have a clearly defined function in sperm's hyperactivated motility and are essential for male fertility. We propose that physiological stimuli such as zona pellucida and cyclic nucleotides induce Ca(2+) entry through CatSper channels instead of acting on Ca(V) and CNG channels as previously thought.
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Affiliation(s)
- Dejian Ren
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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15
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Bhandari B, Bansal P, Talwar P, Gupta SK. Delineation of downstream signalling components during acrosome reaction mediated by heat solubilized human zona pellucida. Reprod Biol Endocrinol 2010; 8:7. [PMID: 20096131 PMCID: PMC2832785 DOI: 10.1186/1477-7827-8-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 01/23/2010] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Human egg is enveloped by a glycoproteinaceous matrix, zona pellucida (ZP), responsible for binding of the human spermatozoa to the egg and induction of acrosomal exocytosis in the spermatozoon bound to ZP. In the present manuscript, attempts have been made to delineate the downstream signalling components employed by human ZP to induce acrosome reaction. METHODS Heat-solubilized human ZP (SIZP) was used to study the induction of acrosome reaction in capacitated human spermatozoa using tetramethylrhodamine isothiocyanate conjugated Pisum sativum agglutinin (TRITC-PSA) in absence or presence of various pharmacological inhibitors. In addition, intracellular calcium ([Ca2+]i) levels in sperm using Fluo-3 acetoxymethyl ester as fluorescent probe were also estimated in response to SIZP. RESULTS SIZP induces acrosomal exocytosis in capacitated human sperm in a dose dependent manner accompanied by an increase in [Ca2+]i. Human SIZP mediated induction of acrosome reaction depends on extracellular Ca2+ and involves activation of Gi protein-coupled receptor, tyrosine kinase, protein kinases A & C and phosphoinositide 3 (PI3)- kinase. In addition, T-type voltage operated calcium channels and GABA-A receptor associated chloride (Cl-) channels play an important role in SIZP mediated induction of acrosome reaction. CONCLUSIONS Results described in the present study provide a comprehensive account of the various downstream signalling components associated with human ZP mediated acrosome reaction.
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Affiliation(s)
- Beena Bhandari
- Reproductive Cell Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110 067, India
| | - Pankaj Bansal
- Reproductive Cell Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110 067, India
| | - Pankaj Talwar
- Assisted Reproduction Technology Centre, Army Hospital Research & Referral, Delhi Cantonment, Delhi-110 010, India
| | - Satish K Gupta
- Reproductive Cell Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi-110 067, India
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16
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Jakop U, Fuchs B, Süss R, Wibbelt G, Braun B, Müller K, Schiller J. The solubilisation of boar sperm membranes by different detergents - a microscopic, MALDI-TOF MS, (31)P NMR and PAGE study on membrane lysis, extraction efficiency, lipid and protein composition. Lipids Health Dis 2009; 8:49. [PMID: 19906304 PMCID: PMC2781011 DOI: 10.1186/1476-511x-8-49] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2009] [Accepted: 11/11/2009] [Indexed: 11/29/2022] Open
Abstract
Background Detergents are often used to isolate proteins, lipids as well as "detergent-resistant membrane domains" (DRMs) from cells. Different detergents affect different membrane structures according to their physico-chemical properties. However, the effects of different detergents on membrane lysis of boar spermatozoa and the lipid composition of DRMs prepared from the affected sperm membranes have not been investigated so far. Results Spermatozoa were treated with the selected detergents Pluronic F-127, sodium cholate, CHAPS, Tween 20, Triton X-100 and Brij 96V. Different patterns of membrane disintegration were observed by light and electron microscopy. In accordance with microscopic data, different amounts of lipids and proteins were released from the cells by the different detergents. The biochemical methods to assay the phosphorus and cholesterol contents as well as 31P NMR to determine the phospholipids were not influenced by the presence of detergents since comparable amounts of lipids were detected in the organic extracts from whole cell suspensions after exposure to each detergent. However, matrix-assisted laser desorption and ionization time-of-flight mass spectrometry applied to identify phospholipids was essentially disturbed by the presence of detergents which exerted particular suppression effects on signal intensities. After separation of the membrane fractions released by detergents on a sucrose gradient only Triton X-100 and sodium cholate produced sharp turbid DRM bands. Only membrane solubilisation by Triton X-100 leads to an enrichment of cholesterol, sphingomyelin, phosphatidylinositol and phosphatidylethanolamine in a visible DRM band accompanied by a selective accumulation of proteins. Conclusion The boar sperm membranes are solubilised to a different extent by the used detergents. Particularly, the very unique DRMs isolated after Triton X-100 exposure are interesting candidates for further studies regarding the architecture of sperm.
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Affiliation(s)
- Ulrike Jakop
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.
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17
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Buffone MG, Rodriguez-Miranda E, Storey BT, Gerton GL. Acrosomal exocytosis of mouse sperm progresses in a consistent direction in response to zona pellucida. J Cell Physiol 2009; 220:611-20. [PMID: 19373867 DOI: 10.1002/jcp.21781] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sperm acrosomal exocytosis is essential for successful fertilization, and the zona pellucida (ZP) has been classically considered as the primary initiator in vivo. At present, following what is referred to as primary binding of the sperm to the ZP, the acrosome reaction paradigm posits that the outer acrosomal membrane and plasma membrane fuse at random points, releasing the contents of the acrosome. It is then assumed that the inner acrosomal membrane mediates secondary binding of the sperm to the ZP. In the present work we used a live fluorescence imaging system and mouse sperm containing enhanced green fluorescent protein (EGFP) in their acrosomes. We compared the processes of acrosomal exocytosis stimulated by the calcium ionophore ionomycin or by solubilized ZP. As monitored by the loss of EGFP from the sperm, acrosomal exocytosis driven by these two agents occurred differently. When ionomycin was used, exocytosis started randomly (no preference for the anterior, middle or posterior acrosomal regions). In contrast, following treatment with solubilized ZP, the loss of acrosomal components always started at the posterior zone of the acrosome and progressed in an anterograde direction. The exocytosis was slower when stimulated with ZP and on the order of 10 sec, which is in accordance with other reports. These results demonstrate that ZP stimulates acrosomal exocytosis in an orderly manner and suggest that a receptor-mediated event controls this process of membrane fusion and release of acrosomal components. These findings are incorporated into a model.
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Affiliation(s)
- Mariano G Buffone
- Department of Obstetrics and Gynecology, Center for Research on Reproduction and Women's Health, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6160, USA
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18
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Krapf D, O'Brien ED, Cabada MO, Visconti PE, Arranz SE. Egg water from the amphibian Bufo arenarum modulates the ability of homologous sperm to undergo the acrosome reaction in the presence of the vitelline envelope. Biol Reprod 2009; 80:311-9. [PMID: 18923159 PMCID: PMC2804820 DOI: 10.1095/biolreprod.108.071076] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 07/09/2008] [Accepted: 10/08/2008] [Indexed: 11/01/2022] Open
Abstract
Sperm from the toad Bufo arenarum must penetrate the egg jelly before reaching the vitelline envelope (VE), where the acrosome reaction is triggered. When the jelly coat is removed, sperm still bind to the VE, but acrosomal exocytosis is not promoted. Our previous work demonstrated that diffusible substances of the jelly coat, termed "egg water" (EW), triggered capacitation-like changes in B. arenarum sperm, promoting the acquisition of a transient fertilizing capacity. In the present work, we correlated this fertilizing capacity with the ability of the sperm to undergo the acrosome reaction, further substantiating the role of the jelly coat in fertilization. When sperm were exposed to the VE, only those preincubated in EW for 5 or 8 min underwent an increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)), which led to acrosomal exocytosis. Responsiveness to the VE was not acquired on preincubation in EW for 2 or 15 min or in Ringer solution regardless of the preincubation time. In contrast, depletion of intracellular Ca(2+) stores (induced by thapsigargin) promoted [Ca(2+)](i) rise and the acrosome reaction even in sperm that were not exposed to EW. Acrosomal exocytosis was blocked by the presence of Ca(2+) chelators independent of whether a physiological or pharmacological stimulus was used. However, Ni(2+) and mibefradil prevented [Ca(2+)](i) rise and the acrosome reaction of sperm exposed to the VE but not of sperm exposed to thapsigargin. These data suggest that the acrosomal responsiveness of B. arenarum sperm, present during a narrow period, is acquired during EW incubation and involves the modulation of a voltage-dependent Ca(2+) channel.
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Affiliation(s)
- Darío Krapf
- Institute of Molecular and Cell Biology of Rosario (Consejo Nacional de Investigaciones Científicas y Técnicas [CONICET]) and Área Biología, Facultad de Ciencias Biológicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
| | - Emma D. O'Brien
- Institute of Molecular and Cell Biology of Rosario (Consejo Nacional de Investigaciones Científicas y Técnicas [CONICET]) and Área Biología, Facultad de Ciencias Biológicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
| | - Marcelo O. Cabada
- Institute of Molecular and Cell Biology of Rosario (Consejo Nacional de Investigaciones Científicas y Técnicas [CONICET]) and Área Biología, Facultad de Ciencias Biológicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
| | - Pablo E. Visconti
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts 01003
| | - Silvia E. Arranz
- Institute of Molecular and Cell Biology of Rosario (Consejo Nacional de Investigaciones Científicas y Técnicas [CONICET]) and Área Biología, Facultad de Ciencias Biológicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
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Patrat C, Auer J, Fauque P, Leandri RL, Jouannet P, Serres C. Zona pellucida from fertilised human oocytes induces a voltage-dependent calcium influx and the acrosome reaction in spermatozoa, but cannot be penetrated by sperm. BMC DEVELOPMENTAL BIOLOGY 2006; 6:59. [PMID: 17147816 PMCID: PMC1712232 DOI: 10.1186/1471-213x-6-59] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Accepted: 12/05/2006] [Indexed: 01/07/2023]
Abstract
Background The functions of three zona glycoproteins, ZP1, ZP2 and ZP3 during the sperm-zona pellucida (ZP) interaction are now well established in mice. The expression of an additional zona glycoprotein, ZPB/4, in humans, led us to reconsider the classical mouse model of gamete interaction. We investigated the various functions of human ZP (hZP) during the interaction of spermatozoa with fertilised and unfertilised oocytes. Results The hZP of fertilised oocytes retained their ability to bind sperm (albeit less strongly than that from unfertilised oocytes), to induce an intraspermatic calcium influx through voltage-dependent channels similar to that observed with hZP from unfertilised oocytes and to promote the acrosome reaction at a rate similar to that induced by the ZP of unfertilised oocytes (61.6 ± 6.2% vs60.7 ± 9.1% respectively). Conversely, the rate of hZP penetrated by sperm was much lower for fertilised than for unfertilised oocytes (19% vs 57% respectively, p < 0.01). We investigated the status of ZP2 in the oocytes used in the functional tests, and demonstrated that sperm binding and acrosome reaction induction, but not ZP penetration, occurred whether or not ZP2 was cleaved. Conclusion The change in ZP function induced by fertilisation could be different in human and mouse species. Our results suggest a zona blocking to polyspermy based at the sperm penetration level in humans.
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Affiliation(s)
- Catherine Patrat
- Biologie de la Reproduction, Hôpital Cochin, AP-HP, Université Paris Descartes, Faculté de Médecine, Paris, France
| | - Jana Auer
- Biologie de la Reproduction, Hôpital Cochin, AP-HP, Université Paris Descartes, Faculté de Médecine, Paris, France
| | - Patricia Fauque
- Biologie de la Reproduction, Hôpital Cochin, AP-HP, Université Paris Descartes, Faculté de Médecine, Paris, France
| | - Roger L Leandri
- Biologie de la Reproduction, Hôpital Cochin, AP-HP, Université Paris Descartes, Faculté de Médecine, Paris, France
| | - Pierre Jouannet
- Biologie de la Reproduction, Hôpital Cochin, AP-HP, Université Paris Descartes, Faculté de Médecine, Paris, France
| | - Catherine Serres
- Biologie de la Reproduction, Hôpital Cochin, AP-HP, Université Paris Descartes, Faculté de Médecine, Paris, France
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20
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Dutt P, Croall DE, Arthur JSC, Veyra TD, Williams K, Elce JS, Greer PA. m-Calpain is required for preimplantation embryonic development in mice. BMC DEVELOPMENTAL BIOLOGY 2006; 6:3. [PMID: 16433929 PMCID: PMC1382200 DOI: 10.1186/1471-213x-6-3] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 01/24/2006] [Indexed: 12/13/2022]
Abstract
Background μ-calpain and m-calpain are ubiquitously expressed proteases implicated in cellular migration, cell cycle progression, degenerative processes and cell death. These heterodimeric enzymes are composed of distinct catalytic subunits, encoded by Capn1 (μ-calpain) or Capn2 (m-calpain), and a common regulatory subunit encoded by Capn4. Disruption of the mouse Capn4 gene abolished both μ-calpain and m-calpain activity, and resulted in embryonic lethality, thereby suggesting essential roles for one or both of these enzymes during mammalian embryogenesis. Disruption of the Capn1 gene produced viable, fertile mice implying that either m-calpain could compensate for the loss of μ-calpain, or that the loss of m-calpain was responsible for death of Capn4-/- mice. Results To distinguish between the alternatives described above, we deleted an essential coding region in the mouse Capn2 gene in embryonic stems cells and transmitted this mutant allele through the mouse germline. Breeding of heterozygous animals failed to produce homozygous mutant live offspring or implanted embryos. A nested PCR genotyping protocol was established, and homozygous preimplantation mutant embryos were detected at the morula but not at the blastocyts stage. Conclusion We conclude that homozygous disruption of the Capn2 gene results in pre-implantation embryonic lethality between the morula and blastocyst stage. This establishes that μ-calpain and m-calpain have distinct functions, and that m-calpain is vital for development of the preimplantation murine embryo.
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Affiliation(s)
- Previn Dutt
- Division of Cancer Biology and Genetics, Queen's University Cancer Research Institute, Queen's University, Kingston, Ontario; K7L 3N6, Canada
- Department of Biochemistry, Queen's University, Kingston, Ontario; K7L 3N6, Canada
| | - Dorothy E Croall
- Department of Biochemistry, Microbiology and Molecular Biology, University of Maine, Orono, Maine, 04469-5735 USA
| | | | - Teresa De Veyra
- Division of Cancer Biology and Genetics, Queen's University Cancer Research Institute, Queen's University, Kingston, Ontario; K7L 3N6, Canada
| | - Karen Williams
- Division of Cancer Biology and Genetics, Queen's University Cancer Research Institute, Queen's University, Kingston, Ontario; K7L 3N6, Canada
| | - John S Elce
- Department of Biochemistry, Queen's University, Kingston, Ontario; K7L 3N6, Canada
| | - Peter A Greer
- Division of Cancer Biology and Genetics, Queen's University Cancer Research Institute, Queen's University, Kingston, Ontario; K7L 3N6, Canada
- Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario; K7L 3N6, Canada
- Department of Biochemistry, Queen's University, Kingston, Ontario; K7L 3N6, Canada
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21
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Hutt DM, Baltz JM, Ngsee JK. Synaptotagmin VI and VIII and Syntaxin 2 Are Essential for the Mouse Sperm Acrosome Reaction. J Biol Chem 2005; 280:20197-203. [PMID: 15774481 DOI: 10.1074/jbc.m412920200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The sperm acrosome is a large secretory granule that undergoes calcium-stimulated exocytosis by a mechanism analogous to neuronal secretion. In neurons the core SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex, composed of syntaxin (Stx), SNAP-25, and VAMP2, mediates vesicle fusion, whereas calcium regulation is thought to be accomplished by the synaptotagmin (Syt) family, some of which exhibit calcium-dependent binding to syntaxin and SNAP-25. Sperm express Syt VI and VIII and Stx2, which are co-localized to the acrosomal compartment where they might mediate exocytosis in response to calcium influx. Therefore, we examined the calcium dependence and isoform-specific interaction of Syt and Stx. We found that Stx2 binds to Syt I, VI, and VIII in a calcium-dependent manner with EC(50) values of 175, 233, and 96 mum calcium, respectively. We also determined that the EC(50) for calcium of the acrosome reaction in streptolysin O-permeabilized sperm is 87 mum, which closely coincides with the calcium sensitivity of Stx2 and Syt VIII interaction. Consistent with this is the greater potency of recombinant Syt VIII, VI, and Stx2 compared with other isoforms in inhibiting the acrosome reaction in streptolysin O-permeabilized sperm. Similarly, introduction of Syt VIII-specific antibodies was equally effective in inhibiting the acrosome fusion. Taken together, our data suggest a critical role for Syt VIII and Stx2 in membrane fusion and acrosome reaction in the sperm.
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Affiliation(s)
- Darren M Hutt
- Ottawa Health Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1Y 4E9, Canada
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22
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Ben-Aharon I, Brown PR, Etkovitz N, Eddy EM, Shalgi R. The expression of calpain 1 and calpain 2 in spermatogenic cells and spermatozoa of the mouse. Reproduction 2005; 129:435-42. [PMID: 15798018 DOI: 10.1530/rep.1.00255] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
There is some evidence suggesting that Ca2+is involved in processes that occur during the development and function of spermatozoa. Calcium-dependent proteins, such as calmodulin, are expressed during mammalian spermatogenesis further suggesting that Ca2+takes part in its regulation. However, the precise roles of Ca2+in spermatogenesis remain to be elucidated. Calpains are a family of Ca2+-dependent cysteine proteases whose members are expressed ubiquitously or in a tissue-specific manner. Calpain has been demonstrated to mediate specific Ca2+-dependent processes including cell fusion, mitosis and meiosis. We herein followed the expression pattern of calpain’s ubiquitous isoforms, 1 and 2, throughout spermatogenesis at the RNA and protein levels by RT-PCR and Western blotting analysis. Both RNA and protein studies revealed that these isoforms are expressed in all spermatogenic cells. The expression of calpain 1 levels is slightly higher in spermatocytes entering the meiotic phase. Both calpain isoforms are also expressed in mouse spermatozoa and are localized to the acrosomal cap. Inducing capacitated spermatozoa to undergo the acrosome reaction in the presence of a selective calpain inhibitor significantly reduced the acrosome reaction rate in a dose-dependent manner. Thus, calpain, a pluripotential protease with numerous substrates, may serve as an effector in more than one pathway in the complex process of spermatogenesis and in the events preceding fertilization, such as the acrosome reaction.
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Affiliation(s)
- Irit Ben-Aharon
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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23
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Harper CV, Barratt CLR, Publicover SJ. Stimulation of Human Spermatozoa with Progesterone Gradients to Simulate Approach to the Oocyte. J Biol Chem 2004; 279:46315-25. [PMID: 15322137 DOI: 10.1074/jbc.m401194200] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Progesterone is present at micromolar concentrations in the cumulus matrix, which surrounds mammalian oocytes. Exposure of human spermatozoa to a concentration gradient of progesterone (0-3 microM) to simulate approach to the oocyte induced a slowly developing increase in [Ca(2+)](i) upon which, in many cells, slow oscillations were superimposed. [Ca(2+)](i) oscillations often started at very low progesterone (<10 nm), and their frequency did not change during the subsequent rise in concentration. Oscillations also occurred, but in a much smaller proportion of cells, in response to stepped application of progesterone (3 microM). When progesterone was removed, [Ca(2+)](i) oscillations often persisted or quickly resumed. Superfusion with low-Ca(2+) bathing medium (no added Ca(2+)) did not prevent [Ca(2+)](i) oscillations, but they could be abolished by addition of EGTA or La(3+). Inhibitors of sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPases or inositol trisphosphate signaling had no effect on [Ca(2+)](i) oscillations, but pharmacological manipulation of ryanodine receptors affected both their frequency and amplitude. Staining of live spermatozoa with BODIPY FL-X ryanodine showed localization of ryanodine binding primarily to the caudal part of the head and mid-piece. [Ca(2+)](i) oscillations did not induce acrosome reaction, but in cells generating oscillations, the flagellar beat mode alternated in synchrony with the oscillation cycle. Flagellar bending and lateral movement of the sperm head during [Ca(2+)](i) peaks were markedly increased compared with during [Ca(2+)](i) troughs. This alternating pattern of activity is likely to facilitate zona penetration. These observations show that progesterone initiates unusual and complex store-mediated [Ca(2+)](i) signaling in human spermatozoa and identify a previously unrecognized effect of progesterone in regulating sperm "behavior" during fertilization.
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Affiliation(s)
- Claire V Harper
- School of Biosciences, Medical School, University of Birmingham, Birmingham, UK
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Hanna WF, Kerr CL, Shaper JH, Wright WW. Lewis X-Containing Neoglycoproteins Mimic the Intrinsic Ability of Zona Pellucida Glycoprotein ZP3 to Induce the Acrosome Reaction in Capacitated Mouse Sperm1. Biol Reprod 2004; 71:778-89. [PMID: 15128591 DOI: 10.1095/biolreprod.103.023820] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The binding of zona pellucida (ZP) glycoprotein ZP3 to mouse sperm surface receptors is mediated by protein-carbohydrate interactions. Subsequently, ZP3 induces sperm to undergo the acrosome reaction, an obligatory step in fertilization. We have previously identified Lewis X (Le(x); Gal beta 4[Fuc alpha 3]GlcNAc) as a potent inhibitor of in vitro sperm-ZP binding (Johnston et al. J Biol Chem 1998; 273:1888-1895). This glycan is recognized by approximately 70% of the ZP3 binding sites on capacitated, acrosome-intact mouse sperm, whereas Lewis A (Le(a); Gal beta 3[Fuc alpha 4]GlcNAc) is recognized by most of the remaining sites (Kerr et al. Biol Reprod 2004; 71:770-777). Herein, we test the hypothesis that Le(x)- and Le(a)-containing glycans, when clustered on a neoglycoprotein, bind ZP3 receptors on sperm and induce sperm to undergo the acrosome reaction via the same signaling pathways as ZP3. Results show that a Le(x)-containing neoglycoprotein induced the acrosome reaction in a dose-dependent and capacitation-dependent manner. A Le(a)-containing neoglycoprotein also induced sperm to undergo the acrosome reaction but was less potent than Le(x)-containing neoglycoproteins. In contrast, neoglycoproteins containing beta4-lactosamine (Gal beta 4GlcNAc), Lewis B (Fuc alpha 2Gal beta 3[Fuc alpha 4]GlcNAc), and sialyl-Le(x) glycans were inactive, as were four other neoglycoproteins with different nonfucosylated glycans. Consistent with these results, unconjugated Le(x)- and Le(a)-capped glycans were dose-dependent inhibitors, which at saturation, reduced the ZP-induced acrosome reaction by about 60% and 30%, respectively. Experiments utilizing pharmacological inhibitors suggest that induction of the acrosome reaction by solubilized ZP and Le(x)- and Le(a)-containing neoglycoproteins require the same calcium-dependent pathway. However, only the ZP-induced acrosome reaction requires a functional G(i) protein. Thus, Le(x)-containing neoglycoproteins bind to a major class of ZP3 receptors on capacitated sperm. A Le(a)-containing neoglycoprotein binds a second ZP3 receptor but is a less-potent inducer of the acrosome reaction.
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Affiliation(s)
- William F Hanna
- Division of Reproductive Biology, Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
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25
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Tomes CN, Roggero CM, De Blas G, Saling PM, Mayorga LS. Requirement of protein tyrosine kinase and phosphatase activities for human sperm exocytosis. Dev Biol 2004; 265:399-415. [PMID: 14732401 DOI: 10.1016/j.ydbio.2003.09.032] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The acrosome is a membrane-limited granule that overlies the nucleus of the mature spermatozoon. In response to physiological or pharmacological stimuli, sperm undergo calcium-dependent exocytosis termed the acrosome reaction, which is an absolute prerequisite for fertilization. Protein tyrosine phosphorylation and dephosphorylation are a mechanisms by which multiple cellular events are regulated. Here we report that calcium induces tyrosine phosphorylation in streptolysin O (SLO)-permeabilized human sperm. As expected, pretreatment with tyrphostin A47-a tyrosine kinase inhibitor-abolishes the calcium effect. Interestingly, the calcium-induced increase in tyrosine phosphorylation has a functional correlate in sperm exocytosis. Masking of phosphotyrosyl groups with a specific antibody or inhibition of tyrosine kinases with genistein, tyrphostin A47, and tyrphostin A51 prevent the acrosome reaction. By reversibly sequestering intra-acrosomal calcium with a photo-inhibitable chelator, we show a requirement for protein tyrosine phosphorylation late in the exocytotic pathway, after the efflux of intra-acrosomal calcium. Both mouse and human sperm contain highly active tyrosine phosphatases. Importantly, this activity declines when sperm are incubated under capacitating conditions. Inhibition of tyrosine phosphatases with pervanadate, bis(N,N-dimethylhydroxoamido)hydroxovanadate, ethyl-3,4-dephostatin, and phenylarsine oxide prevents the acrosome reaction. Our results show that both tyrosine kinases and phosphatases play a central role in sperm exocytosis.
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Affiliation(s)
- C N Tomes
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM-CONICET), Facultad de Ciencias Médicas, CC56, Universidad Nacional de Cuyo, 5500 Mendoza, Argentina.
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26
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Jaiswal BS, Conti M. Calcium regulation of the soluble adenylyl cyclase expressed in mammalian spermatozoa. Proc Natl Acad Sci U S A 2003; 100:10676-81. [PMID: 12958208 PMCID: PMC196863 DOI: 10.1073/pnas.1831008100] [Citation(s) in RCA: 194] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2003] [Indexed: 11/18/2022] Open
Abstract
In mammals, Ca2+ and HCO3- ions play a critical role in the regulation of sperm function, most likely by regulation of cAMP levels. Mammalian germ cells contain a soluble adenylyl cyclase (sAC) with properties distinct from the well characterized membrane-bound enzymes Here we investigated whether the cyclase expressed in mature spermatozoa has the properties of sAC and whether it is regulated by Ca2+. In addition to an HCO3--dependent activation, the cyclase endogenous to human spermatozoa is stimulated 2- to 3-fold by Ca2+ in a concentration-dependent manner (EC50 approximately 400 nM). In a similar fashion, Ca2+ activates the recombinant rat and human full-length sAC with similar EC50 values. The Ca2+ stimulation was also observed when sAC was activated with HCO3-, was independent of calmodulin, and was associated with an increase in Vmax without changes in Km for ATP-Mg2+. An increase in intracellular Ca2+ by ionophore or by a muscarinic cholinergic receptor agonist increases cAMP in cells transfected with FL-hsAC, but not in mock-transfected cells. Similarly, both Ca2+ and HCO3- stimulate cAMP accumulation in human spermatozoa. These findings provide evidence that human spermatozoa express a cyclase with the properties of sAC and that Ca2+ can substitute for HCO3- in the stimulation of this enzyme, underscoring an important role for sAC in the control of sperm functions.
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Affiliation(s)
- Bijay S Jaiswal
- Division of Reproductive Biology, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA 94305-5317, USA
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27
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Bajpai M, Asin S, Doncel GF. Effect of tyrosine kinase inhibitors on tyrosine phosphorylation and motility parameters in human sperm. ARCHIVES OF ANDROLOGY 2003; 49:229-46. [PMID: 12746102 DOI: 10.1080/01485010390196715] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Tyrosine phosphorylation has recently been associated with capacitation and suggested as a regulator of sperm movement, especially characterizing hyperactivation. The objective of this study was to verify if tyrosine phosphorylation of human sperm proteins was essentially required for the maintenance of motility as well as the development of hyperactivation. Washed sperm were incubated for 6 h in Ham's F10 + 0.35% HSA at 37 degrees C in 5% CO(2), with and without the tyrosine kinase inhibitors genistein, tyrphostin, erbstatin, or herbimycin A and the wide-spectrum kinase inhibitor staurosporin. The concentrations of the inhibitors used in the experiments did not induce sperm toxicity, as measured by membrane integrity and mitochondrial function assays. Samples incubated without the inhibitors (control), increased their tyrosine kinase activity (ELISA), the number and intensity of tyrosine-phosphorylated (PY) protein bands (Western blot), the incidence of PY-immunoreactive sperm (immunofluorescence), and some of the sperm motion characteristics (CASA), such as velocity (VEL), amplitude of lateral head displacement (ALH), and hyperactivation. Among the selective protein tyrosine kinase inhibitors, genistein was the most active and consistent, inhibiting sperm tyrosine kinase activity, PY proteins, incidence of PY sperm, and sperm motility and motion parameters, such as VEL, ALH, and hyperactivation. The rest of the kinase inhibitors decreased motion characteristics to a varied extent and had different effects on phosphorylation parameters. In general, they decreased PY phosphorylation of 2 proteins (83 and 54 kDa) present in whole sperm extracts, and two sets of proteins of low (39-49 kDa) and medium (55-87 kDa) molecular weight present in the Triton X-100-solubilized sperm protein fraction. This inhibition was evident regardless of the total tyrosine kinase activity of the samples or the incidence of PY-immunoreactive sperm. The described findings further support the association between motility and protein tyrosine phosphorylation in human sperm and point to certain proteins as the main linkers.
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Affiliation(s)
- M Bajpai
- CONRAD Program, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA
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28
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Yuan YY, Chen WY, Shi QX, Mao LZ, Yu SQ, Fang X, Roldan ERS. Zona pellucida induces activation of phospholipase A2 during acrosomal exocytosis in guinea pig spermatozoa. Biol Reprod 2003; 68:904-13. [PMID: 12604641 DOI: 10.1095/biolreprod.102.005777] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Phospholipase A(2) (PLA(2)) is activated in spermatozoa in response to progesterone and Ca(2+) ionophores, but to our knowledge, no study has yet reported zona pellucida (ZP)-induced activation of PLA(2). We investigated whether PLA(2) is involved in ZP-stimulated acrosomal exocytosis, if Ca(2+) is required for activation of PLA(2), and signal transduction pathways modulating PLA(2) using guinea pig sperm as a model. Spermatozoa were capacitated and labeled in low-Ca(2+) medium with [(14)C]choline chloride or [(14)C]arachidonic acid and were then exposed to millimolar Ca(2+) and various reagents and stimulated with ZP. Precapacitated spermatozoa exposed to millimolar Ca(2+) and stimulated with ZP experienced increases in arachidonic acid (AA) and lysophosphatidylcholine (lysoPC) levels and a parallel decrease in phosphatidylcholine level; these changes are indicative of PLA(2) activation. Simulation with ZP also led to acrosomal exocytosis in a high proportion of spermatozoa. Lipid changes and exocytosis were prevented if spermatozoa were exposed to aristolochic acid, a PLA(2) inhibitor, before treatment with ZP. Stimulation with ZP in medium without added Ca(2+) or in medium with millimolar Ca(2+) and EGTA or La(3+) resulted in no lipid changes or exocytosis. Pretreatment with pertussis toxin, a G(i) protein inhibitor, before stimulation with ZP blocked the release of AA and lysoPC as well as acrosomal exocytosis. Exposure of spermatozoa to the diacylglycerol (DAG) kinase inhibitor R59022 before ZP stimulation led to a significant increase in generation of lysoPC and exocytosis. Taken together, these results indicate very strongly that PLA(2) plays an essential role in ZP-induced exocytosis in spermatozoa, that PLA(2) activation requires Ca(2+) internalization, and that PLA(2) activation is regulated by signal transduction pathways involving G proteins and DAG.
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Affiliation(s)
- Y Y Yuan
- Zhejiang Academy of Medical Sciences, Hangzhou, Zhejiang 310013, People's Republic of China
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29
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Pommer AC, Linfor JJ, Meyers SA. Capacitation and acrosomal exocytosis are enhanced by incubation of stallion spermatozoa in a commercial semen extender. Theriogenology 2002; 57:1493-501. [PMID: 12054207 DOI: 10.1016/s0093-691x(02)00659-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Preserved stallion semen often has decreased spermatozoal motility and fertility that can vary significantly between individual stallions. It is not known whether the medium used for extending equine sperm contributes to these decreases by inducing premature capacitation during storage. If spermatozoa undergo capacitation or acrosome reaction prior to insemination, this could result in a diminished capacity to penetrate the cumulus mass and fertilize the egg. We hypothesized that skim milk-based semen extenders, similar to those used in cooled storage, stabilize sperm membranes and prolong sperm motility and longevity. However, this could decrease the efficiency of sperm to undergo subsequent capacitation in vivo. This study was designed to evaluate the effects from two media on sperm function. Spermatozoal motility was analyzed, intracellular calcium was measured, and the ability of sperm to undergo acrosome reaction was compared after incubation in a skim milk extender (SME) and Tyrode's medium containing albumin, lactate, and pyruvate (TALP) at 37 degrees C. Results suggest that the SME facilitated capacitation as detected by an increase in both intracellular calcium and acrosome reactions, and a decrease in motility, as compared to TALP. Our data support a shortened functional lifespan for equine sperm in skim milk extender, which indicates that further refinements in cooled semen preservation are required to improve fertility of transported equine semen.
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Affiliation(s)
- Angela C Pommer
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616, USA
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Abstract
Following ejaculation, sperm functions are regulated by interactions with the environment found in the female genital tract. Here spermatozoa become 'capacitated' (i.e. they acquire the capability of completing the acrosome reaction and successfully fertilizing the egg), through a series of surface and intracellular transformations occurring during a process known as capacitation. The limited number of spermatozoa that eventually reach the oocyte must then cross the surrounding cumulus cells before contacting the zona pellucida, undergoing the acrosome reaction and finally fertilizing the oocyte. All the interactions between sperm and their diverse environments are mediated by intracellular signaling pathways. Virtually all the signaling systems known to operate in somatic cells, with the exception of those implying nuclear activity, have been found in spermatozoa, although in some cases the function(s) of the pathway has not been clearly proved.
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Affiliation(s)
- Elisabetta Baldi
- Dipartimento di Fisiopatologia Clinica, Unità di Andrologia, Universita' di Firenze, viale Pieraccini 6, I-50139 Florence, Italy.
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Hutt DM, Cardullo RA, Baltz JM, Ngsee JK. Synaptotagmin VIII is localized to the mouse sperm head and may function in acrosomal exocytosis. Biol Reprod 2002; 66:50-6. [PMID: 11751263 DOI: 10.1095/biolreprod66.1.50] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The acrosome is a large secretory granule that undergoes exocytosis when receptors on the sperm surface bind ligands in the egg extracellular matrix. Acrosomal exocytosis resembles stimulated secretion in neurons in that it is triggered by a rise in intracellular Ca(2+). Synaptotagmins (Syt) comprise proteins thought to transduce this Ca(2+) signal to the fusion machinery. In this study, we showed that Syt VIII is present in spermatogenic cDNA libraries. Antiserum raised against a Syt VIII-specific peptide, which recognizes Syt VIII but does not cross-react with other Syt isoforms, labeled a single prominent band on Western immunoblots of mouse sperm homogenate. Syt VIII was restricted to the sperm membrane fraction enriched in markers associated with the mouse sperm head. Fluorescent immunocytochemistry on intact mouse sperm showed that Syt VIII is localized to the acrosomal crescent and is lost upon acrosome reaction. Moreover, the amount of Syt VIII remaining with the sperm decreased proportionately with the extent of acrosome-reacted sperm. Thus, Syt VIII is a candidate for the Ca(2+) sensor that regulates acrosomal exocytosis in mammalian sperm.
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Affiliation(s)
- Darren M Hutt
- Department of Cellular and Molecular Medicine, Ottawa Health Research Institute, University of Ottawa, Ottawa, Ontario K1Y 4E9, Canada
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32
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Visconti PE, Westbrook VA, Chertihin O, Demarco I, Sleight S, Diekman AB. Novel signaling pathways involved in sperm acquisition of fertilizing capacity. J Reprod Immunol 2002; 53:133-50. [PMID: 11730911 DOI: 10.1016/s0165-0378(01)00103-6] [Citation(s) in RCA: 242] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Capacitation is a complex series of molecular events that occurs in sperm after epididymal maturation and confers on sperm the ability to fertilize an egg. This process can be mimicked in vitro in defined media, the composition of which is based on the electrolyte concentration of oviductal fluid. In most cases, capacitation media contain energy substrates, such as pyruvate, lactate and glucose, a cholesterol acceptor (usually serum albumin), NaHCO(3), Ca(2+), low K(+), and physiological Na(+) concentrations. The mechanism of action by which these compounds promote capacitation is poorly understood at the molecular level; however, some molecular events significant to the initiation of capacitation have been identified. For example, capacitation correlates with cholesterol efflux from the sperm plasma membrane, increased membrane fluidity, modulations in intracellular ion concentrations, hyperpolarization of the sperm plasma membrane and increased protein tyrosine phosphorylation. These molecular events are required for the subsequent induction of hyperactivation and the acrosome reaction. This review discusses the recent progress that has been made in elucidating mechanisms which regulate sperm capacitation.
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Affiliation(s)
- P E Visconti
- Center for Recombinant Gamete Contraceptive Vaccinogens, Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA.
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Bains R, Miles DM, Carson RJ, Adeghe J. Hyaluronic acid increases motility/intracellular CA2+ concentration in human sperm in vitro. ARCHIVES OF ANDROLOGY 2001; 47:119-25. [PMID: 11554683 DOI: 10.1080/014850101316901325] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study investigated the mechanisms of the stimulatory effect of hyaluronic acid on motility in human sperm in vitro. A method, involving the measurement of forward progression through an agarose gel. was used to measure sperm motility quantitatively. Changes in intracellular Ca2+ concentrations in sperm were detected using the fluorescent dye Fluo-3. The effects of hyaluronic acid (6.5, 65, 650 ng/mL) and nifedipine (32 nM) on sperm motility were investigated. The effects of hyaluronic acid, nifedipine (32 nM), A23187 (32 microM), and a monoclonal antibody to human CD44 (1 microg/mL) on changes in intracellular CA2+ concentrations were investigated. Hyaluronic acid significantly (p < .008) stimulated sperm motility and this was partially inhibited by nifedipine. A23187 significantly (p < .005) increased intracellular CA2+ concentrations. Hyaluronic acid significantly (p < .04) increased intracellular Ca2+ concentrations and this was inhibited by nifedipine and a monoclonal antibody to human CD44. Hyaluronic acid stimulated human sperm motility by increasing intracellular Ca2+ concentration, partially via an influx of extracellular Ca2+.
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Affiliation(s)
- R Bains
- Division of Biomedical Sciences, School of Health Sciences, University of Wolverhampton, UK
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34
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Flesch FM, Gadella BM. Dynamics of the mammalian sperm plasma membrane in the process of fertilization. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1469:197-235. [PMID: 11063883 DOI: 10.1016/s0304-4157(00)00018-6] [Citation(s) in RCA: 346] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Sexual reproduction requires the fusion of sperm cell and oocyte during fertilization to produce the diploid zygote. In mammals complex changes in the plasma membrane of the sperm cell are involved in this process. Sperm cells have unusual membranes compared to those of somatic cells. After leaving the testes, sperm cells cease plasma membrane lipid and protein synthesis, and vesicle mediated transport. Biophysical studies reveal that lipids and proteins are organized into lateral regions of the sperm head surface. A delicate reorientation and modification of plasma membrane molecules take place in the female tract when sperm cells are activated by so-called capacitation factors. These surface changes enable the sperm cell to bind to the extra cellular matrix of the egg (zona pellucida, ZP). The ZP primes the sperm cell to initiate the acrosome reaction, which is an exocytotic process that makes available the enzymatic machinery required for sperm penetration through the ZP. After complete penetration the sperm cell meets the plasma membrane of the egg cell (oolemma). A specific set of molecules is involved in a disintegrin-integrin type of anchoring of the two gametes which is completed by fusion of the two gamete plasma membranes. The fertilized egg is activated and zygote formation preludes the development of a new living organism. In this review we focus on the involvement of processes that occur at the sperm plasma membrane in the sequence of events that lead to successful fertilization. For this purpose, dynamics in adhesive and fusion properties, molecular composition and architecture of the sperm plasma membrane, as well as membrane derived signalling are reviewed.
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Affiliation(s)
- F M Flesch
- Department of Biochemistry and Cell Biology, and Department of Farm Animal Health, Graduate School of Animal Health and Institute for Biomembranes, Utrecht University, Yalelaan 2, 3584 CM, Utrecht, The Netherlands
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35
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Abstract
Sperm-egg interaction is a carbohydrate-mediated species-specific event which initiates a signal transduction cascade resulting in the exocytosis of sperm acrosomal contents (i.e., the acrosome reaction). This step is believed to be a prerequisite which enables the acrosome-reacted spermatozoa to penetrate the zona pellucida (ZP) and fertilize the egg. Successful fertilization in the mouse and several other species, including man, involves several sequential steps. These are (1) sperm capacitation in the female genital tract; (2) binding of capacitated spermatozoa to the egg's extracellular coat, the ZP; (3) induction of acrosome reaction (i.e., sperm activation); (4) penetration of the ZP; and (5) fusion of spermatozoon with the egg vitelline membrane. This minireview focuses on the most important aspects of the sperm acrosome, from its formation during sperm development in the testis (spermatogenesis) to its modification in the epididymis and function following sperm-egg interaction. Special emphasis has been given to spermatogenesis, a complex process involving multiple molecular events during mitotic cell division, meiosis, and the process of spermiogenesis. The last event is the final phase when a nondividing round spermatid is transformed into the complex structure of the spermatozoon containing a well-developed acrosome. Our intention is also to briefly discuss the functional significance of the contents of the sperm acrosome during fertilization. It is important to mention that only the carbohydrate-recognizing receptor molecules (glycohydrolases, glycosyltransferases, and/or lectin-like molecules) present on the surface of capacitated spermatozoa are capable of binding to their complementary glycan chains on the ZP. The species-specific binding event starts a calcium-dependent signal transduction pathway resulting in sperm activation. The hydrolytic and proteolytic enzymes released at the site of sperm-zona interaction along with the enhanced thrust of the hyperactivated beat pattern of the bound spermatozoon, are important factors in regulating the penetration of the zona-intact egg.
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Affiliation(s)
- A Abou-Haila
- UFR Biomedicale, Université René Descartes, 45, Rue des Saints-Pères, Paris, 75270, France
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36
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Kobori H, Miyazaki S, Kuwabara Y. Characterization of intracellular Ca(2+) increase in response to progesterone and cyclic nucleotides in mouse spermatozoa. Biol Reprod 2000; 63:113-20. [PMID: 10859249 DOI: 10.1095/biolreprod63.1.113] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Rises in intracellular Ca(2+) concentration ([Ca(2+)](i)) caused by progesterone, an inducer of the acrosome reaction, or by cyclic nucleotides, possible second messengers, were investigated by Ca(2+) imaging of the head of individual mouse sperm. Progesterone induced a [Ca(2+)](i) rise in a dose-dependent manner (4-40 microM), primarily in the postacrosomal region. For 20-microM progesterone, Ca(2+) responses occurred in 42% of sperm, separated into two types: transient type (60% of responding cells; duration, 1-1.5 min; mean amplitude, 335 nM) and prolonged type (40%; >3 min; 730 nM). Prolonged responses required higher doses of progesterone, and their occurrence was enhanced significantly by preincubation for 2-4 h as compared with transient responses. 8-Bromo-cGMP (0.3-3 mM) induced a [Ca(2+)](i) rise more effectively than did 8-bromo-cAMP. For 1-mM 8-bromo-cGMP, 90% of cells exhibited transient Ca(2+) responses (approximately 1 min; 220 nM), independently of the preincubation time. In Ca(2+)-free medium, most sperm showed no Ca(2+) response to progesterone and 8-bromo-cGMP. Pimozide, a Ca(2+) channel blocker, completely blocked prolonged responses and partially inhibited transient responses. These results suggest that progesterone activates at least two distinct Ca(2+) influx pathways, with fast or slow inactivation kinetics, and some sperm show both types of response. A cyclic nucleotide-mediated process could participate in the progesterone-induced [Ca(2+)](i) rise.
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Affiliation(s)
- H Kobori
- Department of Physiology, Tokyo Women's Medical University School of Medicine, Tokyo, Japan
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37
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O'Toole CM, Arnoult C, Darszon A, Steinhardt RA, Florman HM. Ca(2+) entry through store-operated channels in mouse sperm is initiated by egg ZP3 and drives the acrosome reaction. Mol Biol Cell 2000; 11:1571-84. [PMID: 10793136 PMCID: PMC14868 DOI: 10.1091/mbc.11.5.1571] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Fertilization occurs after the completion of the sperm acrosome reaction, a secretory event that is triggered during gamete adhesion. ZP3, an egg zona pellucida glycoprotein, produces a sustained increase of the internal Ca(2+) concentration in mouse sperm, leading to acrosome reactions. Here we show that the sustained Ca(2+) concentration increase is due to the persistent activation of a Ca(2+) influx mechanism during the late stages of ZP3 signal transduction. These cells also possess a Ca(2+) store depletion-activated Ca(2+) entry pathway that is open after treatment with thapsigargin. Thapsigargin and ZP3 activate the same Ca(2+) permeation mechanism, as demonstrated by fluorescence quenching experiments and by channel antagonists. These studies show that ZP3 generates a sustained Ca(2+) influx through a store depletion-operated pathway and that this drives the exocytotic acrosome reaction.
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Affiliation(s)
- C M O'Toole
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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38
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Rockwell PL, Storey BT. Kinetics of onset of mouse sperm acrosome reaction induced by solubilized zona pellucida: fluorimetric determination of loss of pH gradient between acrosomal lumen and medium monitored by dapoxyl (2-aminoethyl) sulfonamide and of intracellular Ca(2+) changes monitored by fluo-3. Mol Reprod Dev 2000; 55:335-49. [PMID: 10657053 DOI: 10.1002/(sici)1098-2795(200003)55:3<335::aid-mrd12>3.0.co;2-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The onset of the zona pellucida-induced acrosome reaction in mouse sperm is marked by loss of the pH gradient existing in acrosome-intact sperm between the acidic acrosomal lumen and the suspending medium, due to pore formation between outer acrosomal and plasma membranes. In earlier work, it was shown that this pH gradient loss occurred in single sperm bound to structurally intact zonae pellucidae with a half-time of 2.1 min; the extended kinetics of this loss determined in a sperm population bound to intact zonae was due to a 180-min range of variable lag times. We hypothesized that this lag time range was due to steric constraints imposed by the three-dimensional structure of the structurally intact zona pellucida, and that this constraint should be removed in solubilized zonae. The fluorescent probe, Dapoxyl(TM) (2-aminoethyl)sulfonamide (DAES) allowed a test of this hypothesis in a population of sperm cells. It is a weak base that is non-fluorescent in aqueous solution, but which accumulates in the acidic acrosomal compartment due to the pH gradient with highly enhanced fluorescence; loss of the pH gradient leads to a decrease in fluorescence. The half-time for DAES fluorescence loss in a population of capacitated, acrosome-intact sperm in response to solubilized zona pellucida protein was 2.13 +/- 0.10 min (SEM, n = 9). The agreement between single cell and cell population kinetics validates the hypothesis of steric constraint in the structurally intact zona pellucida. The change in intracellular Ca(2+) concentration in response to solubilized zona pellucida, as monitored with fluo-3, was a rapid increase, followed by a decrease, with a half-time of 0.85 +/- 0.09 min (SEM, n = 6) to a steady state level higher than the initial level, indicating this Ca(2+) transient as the precursor reaction to onset of the zona-induced acrosome reaction.
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Affiliation(s)
- P L Rockwell
- Center for Research on Reproduction and Women's Health, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104-6142, USA
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39
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Rockwell PL, Storey BT. Determination of the intracellular dissociation constant, K(D), of the fluo-3. Ca(2+) complex in mouse sperm for use in estimating intracellular Ca(2+) concentrations. Mol Reprod Dev 1999; 54:418-28. [PMID: 10542383 DOI: 10.1002/(sici)1098-2795(199912)54:4<418::aid-mrd13>3.0.co;2-i] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In order to calculate the actual, rather than the relative, intracellular Ca(2+) concentration (Ca(2+))(i) in mammalian sperm cells, using fluorescent probes whose fluorescence emission differs between the probe. Ca(2+) complex and free probe, the value of the dissociation constant for the probe. Ca(2+) complex, K(D), is required. Interaction of the probe with cellular components may change the intracellular value of K(D) from that determined in buffered solution. We had previously shown that fluo-3, whose Ca(2+) complex is highly fluorescent whereas free fluo-3 is not, could be used to monitor changes of (Ca(2+))(i) in mouse sperm. In this report, we describe a method for determining K(D) for the fluo-3. Ca(2+) complex in mouse sperm suspended in medium MJB, a medium in which the sperm remain viable, but which contains high Ca(2+). The method involved treating the sperm with ionomycin to provide a plasma membrane Ca(2+) carrier, with nigericin to eliminate pH gradient, and with gramicidin D to eliminate membrane potential, such that (Ca(2+))(i) equilibrates with medium Ca(2+) concentration (Ca(2+))(e), then titrating (Ca(2+))(e) with EGTA in added aliquots to near nil concentration. At EGTA concentrations in excess of total medium Ca(2+), an approximation algorithm was used to calculate (Ca(2+))(e), based on the known K(D) for the EGTA. Ca(2+) complex. The fluorescence of the intracellular fluo-3. Ca(2+) complex, F, decreased with increasing additions of EGTA; (Ca(2+))(i) = (Ca(2+))(e) was plotted as a linear function of F/[F(max) - F]; the slope gives K(D). At 37 degrees C, intracellular K(D) was calculated to be 0.636 +/- 0.018 microM (+/-SEM, n = 8). At 37 degrees C and 20 degrees C, K(D) values in MJB were calculated to be 0.502 +/- 0.022 and 0.578 +/- 0.029 (+/-SEM, n =8 and n = 6), respectively. The higher intracellular K(D) value implies probe interaction with cytosol components, primarily those in the head, as this compartment is the major contributor to sperm fluorescence. Changes in (Ca(2+))(i), monitored with fluo-3 fluorescence, that occur on interaction of capacitated mouse sperm with the zona pellucida and may now be quantified, using 0.636 microM for K(D) of the intracellular fluo-3. Ca(2+) complex.
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Affiliation(s)
- P L Rockwell
- Center for Research on Reproduction and Women's Health, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104-6142, USA
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40
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Loeser CR, Lynch C, Tulsiani DR. Characterization of the pharmacological-sensitivity profile of neoglycoprotein-induced acrosome reaction in mouse spermatozoa. Biol Reprod 1999; 61:629-34. [PMID: 10456838 DOI: 10.1095/biolreprod61.3.629] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Mammalian spermatozoa undergo the acrosome reaction (AR) in response to the interaction of a carbohydrate-recognizing molecule(s) on the sperm plasma membrane (sperm surface receptor) and its complementary glycan (ligand) moiety(ies) on the zona pellucida (ZP). Previously, we demonstrated that a hexose (mannose) or two amino sugars (glucosaminyl or galactosaminyl residues) when covalently conjugated to a protein backbone (neoglycoproteins) mimicked the mouse ZP3 glycoprotein and induced the AR in capacitated mouse spermatozoa (Loeser and Tulsiani, Biol Reprod 1999; 60:94-101). To elucidate the mechanism underlying sperm-neoglycoprotein interaction and the induction of the AR, we have examined the effect of several AR blockers on neoglycoprotein-induced AR. Our data demonstrate that two known L-type Ca(2+) channel blockers prevented the induction of the AR by three neoglycoproteins (mannose-BSA, N-acetylglucosamine-BSA, and N-acetylgalactosamine-BSA). The fact that the L-type Ca(2+) channel blockers (verapamil, diltiazem) had no inhibitory effect on sperm surface galactosyltransferase or alpha-D-mannosidase, two carbohydrate-recognizing enzymes thought to be sperm surface receptors, suggests that the reagents block the AR by a mechanism other than binding to the active site of the enzymes.
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Affiliation(s)
- C R Loeser
- Center for Reproductive Biology Research and Departments of Obstetrics and Gynecology and Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2633, USA
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41
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Arnoult C, Kazam IG, Visconti PE, Kopf GS, Villaz M, Florman HM. Control of the low voltage-activated calcium channel of mouse sperm by egg ZP3 and by membrane hyperpolarization during capacitation. Proc Natl Acad Sci U S A 1999; 96:6757-62. [PMID: 10359785 PMCID: PMC21988 DOI: 10.1073/pnas.96.12.6757] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sperm adhesion to egg zonae pellucidae initiates sperm acrosome reactions, an exocytotic event that is an early step during fertilization. Previously, it was suggested that zona pellucida-evoked Ca2+ entry into sperm through low voltage-activated Ca2+ channels is an essential step in acrosome reactions, based on the inhibitory effects of Ca2+ channel antagonists. However, analysis of this channel is limited by the inability to apply electrophysiological methods directly to sperm. In this report, optical methods of determining membrane potential and internal Ca2+ levels were used to demonstrate that (i) contact with zonae pellucidae activates a transient Ca2+ response in sperm that has a time course and antagonist sensitivity anticipated of low voltage-activated Ca2+ channels; (ii) these channels are unavailable for opening in uncapacitated sperm because of voltage-dependent, steady state inactivation; (iii) membrane hyperpolarization during sperm capacitation is sufficient to recruit channels into a closed state, from which they are available for opening during fertilization; and (iv) channel conductance state may be a factor in determines the efficacy with which channel antagonists inhibit fertilization. This study provides evidence for the activation of sperm Ca2+ channels during gamete adhesion and offers a mechanism that may account for aspects of the regulation of sperm fertility during capacitation through the control of channel availability. Finally, these results suggest that channel conductance state may be a central feature in the design of channel antagonists that inhibit sperm function.
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Affiliation(s)
- C Arnoult
- Centre d'Etudes de Grenoble, Departement de Biologie Moleculaire et Structurale, 38054 Grenoble, France
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42
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Domínguez L, Yunes RM, Fornés MW, Burgos M, Mayorga LS. Calcium and phospholipase A2 are both required for the acrosome reaction mediated by G-proteins stimulation in human spermatozoa. Mol Reprod Dev 1999; 52:297-302. [PMID: 10206661 DOI: 10.1002/(sici)1098-2795(199903)52:3<297::aid-mrd7>3.0.co;2-t] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
G-proteins, calcium, and phospholipase A2 (PLA2) have all been implicated in the cascade of signaling events leading to the acrosome reaction in human spermatozoa. In order to study the role of Ca+2 and PLA2 during the acrosome reaction triggered by G-proteins, we treated human spermatozoa incubated for 3 hr under capacitating conditions with several reagents (GTPgammaS, A23187, ONO-RS-082, arachidonic acid, BAPTA-AM, and TPEN), alone or in different combinations. Our results suggest that GTP-binding proteins require Ca+2 and PLA2 to accomplish their stimulatory effect, and that Ca+2 is also required when the acrosome reaction--bypassing the action of PLA2--is stimulated by AA. Accordingly, when treated with GTPgammaS or AA, the cells loaded with Fura 2-AM showed a steady increase of [Ca+2]i. On the other hand, a massive influx of Ca+2 was completely unable to induce the acrosome reaction if PLA2 was inhibited, suggesting that both an increase of [Ca+2]i and PLA2 activation are required for the acrosome reaction to occur.
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Affiliation(s)
- L Domínguez
- Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina
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43
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Storey BT, Noiles EE, Thompson KA. Comparison of glycerol, other polyols, trehalose, and raffinose to provide a defined cryoprotectant medium for mouse sperm cryopreservation. Cryobiology 1998; 37:46-58. [PMID: 9698429 DOI: 10.1006/cryo.1998.2097] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Most procedures for mouse sperm cryopreservation have utilized raffinose to provide hypertonicity for cell desiccation prior to freezing and glycerol to block intracellular ice formation. Trehalose has been shown in other cell systems to provide positive protection to the plasma membrane and so was examined as a replacement for raffinose. Comparison of 3 and 6% glycerol and 7.5 and 20% sugar showed that 6% glycerol and 7.5% sugar gave maximal protection consistently and so were adopted as standard. Comparison of raffinose and trehalose at this concentration showed trehalose to give significantly better recovery of intact cells: 48 +/- 6% for trehalose, 36 +/- 9% for raffinose (+/- SE, n = 5; arc sine transformed data; P < 0.01). Less hydrophilic polyols should prove more permeant to the membrane than glycerol, enter the cell rapidly, and so possibly inhibit lethal intracellular ice formation effectively. We hypothesized that one of these polyols plus glycerol would be a more effective cryoprotectant than glycerol alone. The polyols tested as supplements to 6% glycerol were propane-1,2-diol, propane-1,3-diol, 1,1,1-tris-(hydroxymethyl)ethane (THME), and 2-ethyl-2-(hydroxymethyl)-propane-1,3-diol (EHMP). With 6% glycerol and 7.5% raffinose or trehalose, the two diols and THME gave less cryoprotection than with glycerol alone, and EHMP reduced postthaw membrane integrity to nil, thus invalidating the hypothesis. Comparison of bicarbonate-containing medium MJB to bicarbonate-free medium NTP, both with 6% glycerol/7.5% trehalose, showed no difference in recovery of membrane-intact cells. For ease of pH maintenance, NTP was chosen for studies of addition prefreeze and removal postthaw of 6% glycerol/7.5% trehalose cryoprotectant with in vitro fertilization as endpoint. Three protocols for cryoprotectant handling were tested: serial addition/dilution; dialysis addition and removal; and dialysis addition and direct insemination without cryoprotectant removal. The last proved significantly superior (P < 0.01), giving 62% fertilized eggs, normalized to controls, compared to 21% for dialysis addition and removal and 32% for serial addition and dilution. The glycerol/trehalose combination thus provides a defined cryoprotectant which, when used with addition by dialysis prefreeze and direct insemination postthaw, yields a satisfactory yield of fertilized eggs in an in vitro fertilization system.
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Affiliation(s)
- B T Storey
- Center for Research on Reproduction and Women's Health, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, 19104, USA
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Florman HM, Arnoult C, Kazam IG, Li C, O'Toole CM. A perspective on the control of mammalian fertilization by egg-activated ion channels in sperm: a tale of two channels. Biol Reprod 1998; 59:12-6. [PMID: 9674987 DOI: 10.1095/biolreprod59.1.12] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Affiliation(s)
- H M Florman
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, MA 02111, USA.
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Pukazhenthi BS, Wildt DE, Ottinger MA, Howard J. Inhibition of domestic cat spermatozoa acrosome reaction and zona pellucida penetration by tyrosine kinase inhibitors. Mol Reprod Dev 1998; 49:48-57. [PMID: 9406195 DOI: 10.1002/(sici)1098-2795(199801)49:1<48::aid-mrd6>3.0.co;2-o] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Spermatozoa from teratospermic domestic cats (> 60% morphologically abnormal spermatozoa per ejaculate) consistently exhibit lower levels of oocyte penetration in vitro than their normospermic (< 40% abnormal spermatozoa per ejaculate) counterparts. This could be caused by structural abnormalities or intracellular defects resulting in disruption of normal cellular functions. Spermatozoa from teratospermic cats also are compromised in the ability to capacitate and undergo the acrosome reaction (AR) in vitro. Further, we recently identified two tyrosine phosphorylated proteins (95- and 160-kDa) localized over the acrosome region in domestic cat spermatozoa. Phosphorylation of these proteins is reduced in teratospermic compared with normospermic ejaculates. To begin to understand the relationship between tyrosine phosphorylation and sperm function, we examined the effects of two protein tyrosine kinase inhibitors (tyrphostin RG-50864 and genistein) on (1) sperm motility; (2) protein tyrosine phosphorylation; (3) the ionophore A23187-induced AR; (4) the spontaneous and zona pellucida (ZP)-induced AR, and (5) the ability of spermatozoa from normospermic cats to penetrate conspecific ZP-intact oocytes. Over a wide range of concentrations, neither inhibitor affected sperm percentage motility during incubation (P > 0.05). Preincubation with either inhibitor reduced tyrosine phosphorylation of both (95- and 160-kDa) sperm proteins. Although both inhibitors blocked the ZP-induced AR, neither influenced the spontaneous AR nor the A23187-induced AR, suggesting that tyrosine phosphorylation may be involved in physiologic AR. No differences (P > 0.05) were observed in the ability of control or inhibitor-treated spermatozoa to bind to or penetrate the outer ZP layer. However, percentages of oocytes with treated spermatozoa in the inner ZP (tyrphostin, 8.7%; genistein, 20.4%) and perivitelline space (tyrphostin, 0%; genistein, 2.3%) were less (P < 0.001) than untreated controls (inner ZP, 62.7%; perivitelline space, 10.2%). These results (1) demonstrate that ZP-induced acrosomal exocytosis in domestic cat spermatozoa is regulated via a tyrosine kinase-dependent pathway and (2) suggest that defects in these signaling pathways may represent one of the causes for compromised sperm function in teratospermic males.
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Affiliation(s)
- B S Pukazhenthi
- Department of Reproductive Physiology, National Zoological Park, Smithsonian Institution, Washington, DC 20008, USA
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46
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Perry RL, Barratt CLR, Warren MA, Cooke ID. Elevating intracellular calcium levels in human sperm using an internal calcium ATPase inhibitor, 2,5-di(tert-butyl) hydroquinone (TBQ), initiates capacitation and the acrosome reaction but only in the presence of extracellular calcium. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/(sici)1097-010x(19971015)279:3<291::aid-jez10>3.0.co;2-d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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47
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Noiles EE, Thompson KA, Storey BT. Water permeability, Lp, of the mouse sperm plasma membrane and its activation energy are strongly dependent on interaction of the plasma membrane with the sperm cytoskeleton. Cryobiology 1997; 35:79-92. [PMID: 9302770 DOI: 10.1006/cryo.1997.2033] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Two parameters fundamental to cell cryobiology are the water permeability (hydraulic conductivity), Lp, and its activation energy, EA. The Lp can be calculated from two experimental determinations: the critical osmolality, Osmcrit, at which 50% of the cells lyse, and the time, tcrit, to 50% lysis in a highly hyposmotic medium, based on the assumption that the cells swell to lysis with minimal resistance to swelling. We have reported [Cryobiology 32, 220-238 (1995)] that mouse sperm in hyposmotic medium show minimal swelling and so fail to meet this assumption. The concept that resistance to swelling was due to anchoring of the plasma membrane through cytoskeletal interaction was examined by treating mouse sperm with 5 microM cytochalasin D to depolymerize the cytoskeletal filamentous actin (f-actin), whose presence was established by staining with fluorescently labeled phalloidin. Diminution of fluorescence due to loss of f-actin induced by cytochalasin D was shown by flow cytometry. Mouse sperm treated with cytochalasin D showed tail curling in hyposmotic medium, similar to that observed with bovine and human sperm, indicating that the standard swelling model was applicable to these cells. Two sets of Lp values were calculated from tcrit: one using individual means of Osmcrit and one using the mean of means of Osmcrit between 37 and 4 degrees C, as these individual means were not significantly different. Values (micron.min-1.atm-1), respectively, were 9.95, 7.15 (37 degrees C); 1.51, 0.91 (22 degrees C); 0.54, 0.78 (12 degrees C); 0.47, 0.50 (4 degrees C); 0.33 (0 degree C); and 0.36 (-3 degrees C). Arrhenius plots gave EA = 13.7 and 11.7 kcal/mol, respectively. Values of t1/2 were calculated from the first-order rate constants characterizing the kinetics of cell lysis at the higher four temperatures; Lp values calculated from these, and the two sets of Osmcrit values described were 5.70, 4.09 (37 degrees C); 1.18, 0.71 (22 degrees C); 0.62, 0.90 (12 degrees C); and 0.34, 0.37 (4 degrees C). Arrhenius plots gave EA = 14.2 and 11.0 kcal/mol, respectively. We propose that these EA values are characteristic of the plasma membrane relatively unperturbed by cytoskeletal interactions. In untreated sperm, decrease of Lp with decreasing temperature and presence of cryoprotectant and the cytoskeletal interactions all act to hamper the sperm cells' ability to respond to osmotic stress encountered during freezing and thawing, such that these cells are especially sensitive to cryodamage.
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Affiliation(s)
- E E Noiles
- Center for Research on Reproduction and Women's Health, University of Pennsylvania Medical Center, Philadelphia 19104, USA
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48
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Maxwell WM, Johnson LA. Chlortetracycline analysis of boar spermatozoa after incubation, flow cytometric sorting, cooling, or cryopreservation. Mol Reprod Dev 1997; 46:408-18. [PMID: 9041145 DOI: 10.1002/(sici)1098-2795(199703)46:3<408::aid-mrd21>3.0.co;2-t] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this study, the effects of staining procedure with chlortetracycline (CTC) and method of analysis of boar spermatozoa after staining were examined. The hypothesis that incubation, flow cytometric sorting, cooling, and cryopreservation cause changes to boar sperm membranes which resemble capacitation and the acrosome reaction was also tested. Membrane status was evaluated by flow cytometry and by fluorescence microscopy after staining with CTC, and acrosome integrity was checked by flow cytometry after staining with FITC-pisum sativum agglutenin and propidium iodide (PI). Flow cytometry was also used to assess viability (percentages of live and dead cells) of boar sperm after staining with SYBR-14 and PI. Staining of spermatozoa with CTC alone and in combination with PI and/or Hoechst 33342 had no effect on the proportion of spermatozoa allocated to the F (uncapacitated), B (capacitated), or AR (acrosome-reacted) CTC fluorescent staining categories. The mean percentages of acrosome-intact and acrosome-reacted cells were 88.4 and 6.8 or 0.8 and 96.5 in semen treated with 0 or 100 microg/ml lysophosphatidylchloine (LPC), respectively (P < 0.001). Most spermatozoa were also in the AR CTC-stained category after treatment with LPC compared with a small proportion in the controls. Using flow cytometry to examine sperm suspensions stained with CTC, a gated population of spermatozoa with low fluorescence (population 1) comprised predominantly F-pattern cells (F-pattern: population 1 vs. population 2, 80.5 vs. 14.4%; P < 0.001), whereas population 2 (high fluorescence) comprised mainly B-pattern cells (B-pattern: population 1 vs. population 2, 8.5 vs. 62.3%; P < 0.001). Incubation (38 degrees C, 4 hr), flow sorting, cooling (to 15 or 5 degrees C) and freezing reduced the proportion of F-pattern and live spermatozoa, and increased the proportion of B-, AR-pattern, and dead spermatozoa, in comparison with fresh semen. There were more membrane changes in spermatozoa cooled to 5 degrees C (30.4, 48.5, 21.1%) than in those cooled to 15 degrees C (56.1, 32.6, 11.5% F-, B-, and AR-pattern spermatozoa, respectively).
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Affiliation(s)
- W M Maxwell
- Department of Animal Science, University of Sydney, Australia
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49
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Murase T, Roldan ER. Progesterone and the zona pellucida activate different transducing pathways in the sequence of events leading to diacylglycerol generation during mouse sperm acrosomal exocytosis. Biochem J 1996; 320 ( Pt 3):1017-23. [PMID: 9003394 PMCID: PMC1218029 DOI: 10.1042/bj3201017] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We tested the involvement of protein tyrosine kinase and G-protein transducing pathways in the formation of diacylglycerol (DAG) during exocytosis in mouse spermatozoa. In capacitated spermatozoa, stimulation with solubilized zona pellucida (ZP) or progesterone led to the formation of DAG and to exocytosis of the acrosomal granule. Stimulation of DAG formation and exocytosis by ZP were inhibited in a concentration-dependent fashion by pre-exposure to tyrphostin A48, a protein tyrosine kinase inhibitor. These ZP-induced responses were also reduced in a concentration-dependent manner by prior incubation with pertussis toxin, a G-protein (Gi class) inhibitor. On the other hand, generation of DAG and exocytosis triggered by progesterone were inhibited if spermatozoa were preincubated with different concentrations of tyrphostin A48, but were not affected by pre-exposure to pertussis toxin. Progesterone acts on at least two novel surface receptors, one being a gamma-aminobutyric acid (GABA) type A (GABAA)-like receptor. Transducing mechanisms coupled to this receptor were tested directly by stimulating spermatozoa with GABA. Treatment of capacitated spermatozoa with GABA resulted in DAG formation and exocytosis. These responses were not seen when cells were preincubated with tyrphostin A48. Pertussis toxin, however, did not affect the generation of DAG and exocytosis triggered by GABA, in agreement with results obtained using progesterone. Taken together, these results indicate that DAG formation during acrosomal exocytosis is differentially regulated by transducing pathways activated by oocyte-associated agonists.
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Affiliation(s)
- T Murase
- Department of Development and Signalling, Babraham Institute, Cambridge, U.K
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50
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Arnoult C, Cardullo RA, Lemos JR, Florman HM. Activation of mouse sperm T-type Ca2+ channels by adhesion to the egg zona pellucida. Proc Natl Acad Sci U S A 1996; 93:13004-9. [PMID: 8917534 PMCID: PMC24036 DOI: 10.1073/pnas.93.23.13004] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The sperm acrosome reaction is a Ca(2+)-dependent exocytotic event that is triggered by adhesion to the mammalian egg's zona pellucida. Previous studies using ion-selective fluorescent probes suggested a role of voltage-sensitive Ca2+ channels in acrosome reactions. Here, wholecell patch clamp techniques are used to demonstrate the expression of functional T-type Ca2+ channels during mouse spermatogenesis. The germ cell T current is inhibited by antagonists of T-type channels (pimozide and amiloride) as well as by antagonists whose major site of action is the somatic cell L-type Ca2+ channel (1,4-dihydropyridines, arylalkylamines, benzothiazapines), as has also been reported for certain somatic cell T currents. In sperm, inhibition of T channels during gamete interaction inhibits zona pellucida-dependent Ca2+ elevations, as demonstrated by ion-selective fluorescent probes, and also inhibits acrosome reactions. These studies directly link sperm T-type Ca2+ channels to fertilization. In addition, the kinetics of channel inhibition by 1,4-dihydropyridines suggests a mechanism for the reported contraceptive effects of those compounds in human males.
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Affiliation(s)
- C Arnoult
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, MA 02111, USA
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