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Sfakianoudis K, Zikopoulos A, Grigoriadis S, Seretis N, Maziotis E, Anifandis G, Xystra P, Kostoulas C, Giougli U, Pantos K, Simopoulou M, Georgiou I. The Role of One-Carbon Metabolism and Methyl Donors in Medically Assisted Reproduction: A Narrative Review of the Literature. Int J Mol Sci 2024; 25:4977. [PMID: 38732193 PMCID: PMC11084717 DOI: 10.3390/ijms25094977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
One-carbon (1-C) metabolic deficiency impairs homeostasis, driving disease development, including infertility. It is of importance to summarize the current evidence regarding the clinical utility of 1-C metabolism-related biomolecules and methyl donors, namely, folate, betaine, choline, vitamin B12, homocysteine (Hcy), and zinc, as potential biomarkers, dietary supplements, and culture media supplements in the context of medically assisted reproduction (MAR). A narrative review of the literature was conducted in the PubMed/Medline database. Diet, ageing, and the endocrine milieu of individuals affect both 1-C metabolism and fertility status. In vitro fertilization (IVF) techniques, and culture conditions in particular, have a direct impact on 1-C metabolic activity in gametes and embryos. Critical analysis indicated that zinc supplementation in cryopreservation media may be a promising approach to reducing oxidative damage, while female serum homocysteine levels may be employed as a possible biomarker for predicting IVF outcomes. Nonetheless, the level of evidence is low, and future studies are needed to verify these data. One-carbon metabolism-related processes, including redox defense and epigenetic regulation, may be compromised in IVF-derived embryos. The study of 1-C metabolism may lead the way towards improving MAR efficiency and safety and ensuring the lifelong health of MAR infants.
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Affiliation(s)
- Konstantinos Sfakianoudis
- Centre for Human Reproduction, Genesis Athens Clinic, 14-16, Papanikoli, 15232 Athens, Greece; (K.S.); (K.P.)
| | - Athanasios Zikopoulos
- Laboratory of Medical Genetics, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece; (A.Z.); (N.S.); (C.K.); (U.G.); (I.G.)
- Obstetrics and Gynecology, Royal Cornwall Hospital, Treliske, Truro TR1 3LJ, UK
| | - Sokratis Grigoriadis
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (S.G.); (E.M.); (P.X.)
| | - Nikolaos Seretis
- Laboratory of Medical Genetics, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece; (A.Z.); (N.S.); (C.K.); (U.G.); (I.G.)
| | - Evangelos Maziotis
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (S.G.); (E.M.); (P.X.)
| | - George Anifandis
- Department of Obstetrics and Gynecology, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41222 Larisa, Greece;
| | - Paraskevi Xystra
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (S.G.); (E.M.); (P.X.)
| | - Charilaos Kostoulas
- Laboratory of Medical Genetics, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece; (A.Z.); (N.S.); (C.K.); (U.G.); (I.G.)
| | - Urania Giougli
- Laboratory of Medical Genetics, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece; (A.Z.); (N.S.); (C.K.); (U.G.); (I.G.)
| | - Konstantinos Pantos
- Centre for Human Reproduction, Genesis Athens Clinic, 14-16, Papanikoli, 15232 Athens, Greece; (K.S.); (K.P.)
| | - Mara Simopoulou
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (S.G.); (E.M.); (P.X.)
| | - Ioannis Georgiou
- Laboratory of Medical Genetics, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece; (A.Z.); (N.S.); (C.K.); (U.G.); (I.G.)
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Morabbi A, Karimian M. Trace and essential elements as vital components to improve the performance of the male reproductive system: Implications in cell signaling pathways. J Trace Elem Med Biol 2024; 83:127403. [PMID: 38340548 DOI: 10.1016/j.jtemb.2024.127403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/02/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024]
Abstract
Successful male fertilization requires the main processes such as normal spermatogenesis, sperm capacitation, hyperactivation, and acrosome reaction. The progress of these processes depends on some endogenous and exogenous factors. So, the optimal level of ions and essential and rare elements such as selenium, zinc, copper, iron, manganese, calcium, and so on in various types of cells of the reproductive system could affect conception and male fertility rates. The function of trace elements in the male reproductive system could be exerted through some cellular and molecular processes, such as the management of active oxygen species, involvement in the action of membrane channels, regulation of enzyme activity, regulation of gene expression and hormone levels, and modulation of signaling cascades. In this review, we aim to summarize the available evidence on the role of trace elements in improving male reproductive performance. Also, special attention is paid to the cellular aspects and the involved molecular signaling cascades.
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Affiliation(s)
- Ali Morabbi
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Iran
| | - Mohammad Karimian
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Iran.
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Breitbart H, Grinshtein E. Mechanisms That Protect Mammalian Sperm from the Spontaneous Acrosome Reaction. Int J Mol Sci 2023; 24:17005. [PMID: 38069328 PMCID: PMC10707520 DOI: 10.3390/ijms242317005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
To acquire the capacity to fertilize the oocyte, mammalian spermatozoa must undergo a series of biochemical reactions in the female reproductive tract, which are collectively called capacitation. The capacitated spermatozoa subsequently interact with the oocyte zona-pellucida and undergo the acrosome reaction, which enables the penetration of the oocyte and subsequent fertilization. However, the spontaneous acrosome reaction (sAR) can occur prematurely in the sperm before reaching the oocyte cumulus oophorus, thereby jeopardizing fertilization. One of the main processes in capacitation involves actin polymerization, and the resulting F-actin is subsequently dispersed prior to the acrosome reaction. Several biochemical reactions that occur during sperm capacitation, including actin polymerization, protect sperm from sAR. In the present review, we describe the protective mechanisms that regulate sperm capacitation and prevent sAR.
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Affiliation(s)
- Haim Breitbart
- The Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel
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Miyazawa Y, Fujinoki M. Enhancement of rat spermatozoal hyperactivation by progesterone. J Reprod Dev 2023; 69:279-290. [PMID: 37690839 PMCID: PMC10602764 DOI: 10.1262/jrd.2023-040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/19/2023] [Indexed: 09/12/2023] Open
Abstract
Progesterone (P) is a well-known enhancer of hyperactivation which is associated with the success of in vitro fertilization (IVF). In this study, we examined whether P-enhanced hyperactivation affected IVF success in rats. When rat spermatozoa were exposed to 10, 20, and 40 ng/ml P, 20 ng/ml P enhanced hyperactivation via the membrane progesterone receptor. In addition, the enhancement of hyperactivation by 20 ng/ml P was regulated by phospholipase C, transmembrane adenylate cyclase, and protein kinase A. However, 20 ng/ml P did not affect IVF success. These results suggest that 20 ng/ml P enhances rat spermatozoal hyperactivation through non-genomic pathways. Because the concentration of P changes during the estrous cycle, it seems that rat spermatozoa are hyperactivated in response to the oviductal environment. However, the effect of 20 ng/ml P does not seem to fully capacitate spermatozoa.
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Affiliation(s)
- Yuki Miyazawa
- Research Laboratory of Laboratory Animals, Research Center for Laboratory Animals, Comprehensive Research Facilities for Advanced Medical Science, School of Medicine, Dokkyo Medical University, Tochigi 321-0293, Japan
| | - Masakatsu Fujinoki
- Research Laboratory of Laboratory Animals, Research Center for Laboratory Animals, Comprehensive Research Facilities for Advanced Medical Science, School of Medicine, Dokkyo Medical University, Tochigi 321-0293, Japan
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Correlation of zinc level in spermoplasm with fertility characteristics of human ejaculate. КЛИНИЧЕСКАЯ ПРАКТИКА 2022. [DOI: 10.17816/clinpract115002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Background: Zinc is essential for the normal functioning of the male reproductive system. The data on the diagnostic value of the determination of zinc in human spermoplasm and the relationship of its level with the main parameters of sperm fertility are contradictory.
Aims: Study of correlations of zinc level in spermoplasm with spermogram characteristics.
Methods: Sperm of men of reproductive age (n=486, average age 33.073.03 years) was studied. In addition to the standard spermogram, MAR tests (IgA, IgG and IgM) were performed in the sperm samples, the degree of fragmentation of sperm DNA was assessed, the interaction of sperm with hyaluronic acid was assessed, acrosine activity, neutral alpha-glucosidase activity was determined, citric acid, fructose and glycodelin levels were determined, the level of reactive oxygen species was studied. Determination of the zinc level in the spermoplasm was carried out by a standard spectrophotometric method with 5-Br-PAPS chromogen. Pearson's formula was used for correlation analysis. The study was conducted from 2018 to May 2022, once.
Results: A significant negative correlation of the zinc level in the spermoplasm with the age of men was revealed (r=-0.1625, p0.001). The level of zinc in the spermoplasm was weakly negatively correlated with the dilution time and with the viscosity of the sperm. The positive correlation was with the number of spermatozoa (r=0.1345, p0.01) and their mobility (r=0.3825, p0.00001). The level of zinc in the spermoplasm negatively correlates with the degree of fragmentation of sperm DNA and with the amount of reactive oxygen species, and with the test for binding of sperm with hyaluronic acid positively.
Conclusions: The level of zinc in the spermoplasm significantly correlates with a number of physiological and biochemical characteristics of sperm. The data obtained allow us to recommend the determination of zinc in the sperm plasma not only to assess the functional activity of the prostate gland, but also to diagnose the fertility of the ejaculate, as well as to optimize therapy with zinc-containing drugs and improve control over the effectiveness of the treatment.
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Maciejewski R, Radzikowska-Büchner E, Flieger W, Kulczycka K, Baj J, Forma A, Flieger J. An Overview of Essential Microelements and Common Metallic Nanoparticles and Their Effects on Male Fertility. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph191711066. [PMID: 36078782 PMCID: PMC9518444 DOI: 10.3390/ijerph191711066] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 05/17/2023]
Abstract
Numerous factors affect reproduction, including stress, diet, obesity, the use of stimulants, or exposure to toxins, along with heavy elements (lead, silver, cadmium, uranium, vanadium, mercury, arsenic). Metals, like other xenotoxins, can cause infertility through, e.g., impairment of endocrine function and gametogenesis or excess production of reactive oxygen species (ROS). The advancement of nanotechnology has created another hazard to human safety through exposure to metals in the form of nanomaterials (NMs). Nanoparticles (NPs) exhibit a specific ability to penetrate cell membranes and biological barriers in the human body. These ultra-fine particles (<100 nm) can enter the human body through the respiratory tract, food, skin, injection, or implantation. Once absorbed, NPs are transported to various organs through the blood or lymph. Absorbed NPs, thanks to ultrahigh reactivity compared to bulk materials in microscale size, disrupt the homeostasis of the body as a result of interaction with biological molecules such as DNA, lipids, and proteins; interfering with the functioning of cells, organs, and physiological systems; and leading to severe pathological dysfunctions. Over the past decades, much research has been performed on the reproductive effects of essential trace elements. The research hypothesis that disturbances in the metabolism of trace elements are one of the many causes of infertility has been unquestionably confirmed. This review examines the complex reproductive risks for men regarding the exposure to potentially harmless xenobiotics based on a series of 298 articles over the past 30 years. The research was conducted using PubMed, Web of Science, and Scopus databases searching for papers devoted to in vivo and in vitro studies related to the influence of essential elements (iron, selenium, manganese, cobalt, zinc, copper, and molybdenum) and widely used metallic NPs on male reproduction potential.
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Affiliation(s)
| | | | - Wojciech Flieger
- Department of Anatomy, Medical University of Lublin, 20-090 Lublin, Poland
| | - Kinga Kulczycka
- Institute of Health Sciences, John Paul II Catholic University of Lublin, 20-708 Lublin, Poland
| | - Jacek Baj
- Department of Anatomy, Medical University of Lublin, 20-090 Lublin, Poland
| | - Alicja Forma
- Department of Forensic Medicine, Medical University of Lublin, ul. Jaczewskiego 8B, 20-090 Lublin, Poland
| | - Jolanta Flieger
- Department of Analytical Chemistry, Medical University of Lublin, Chodźki 4A, 20-093 Lublin, Poland
- Correspondence: ; Tel.: +48-81448-7182
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Carlson EJ, Francis R, Liu Y, Li P, Lyon M, Santi CM, Hook DJ, Hawkinson JE, Georg GI. Discovery and Characterization of Multiple Classes of Human CatSper Blockers. ChemMedChem 2022; 17:e202000499. [PMID: 35644882 PMCID: PMC9378630 DOI: 10.1002/cmdc.202000499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 05/25/2022] [Indexed: 11/25/2022]
Abstract
The cation channel of sperm (CatSper) is a validated target for nonhormonal male contraception, but it lacks selective blockers, hindering studies to establish its role in both motility and capacitation. Via an innovative calcium uptake assay utilizing human sperm we discovered novel inhibitors of CatSper function from a high-throughput screening campaign of 72,000 compounds. Preliminary SAR was established for seven hit series. HTS hits or their more potent analogs blocked potassium-induced depolarization and noncompetitively inhibited progesterone-induced CatSper activation. CatSper channel blockade was confirmed by patch clamp electrophysiology and these compounds inhibited progesterone- and prostaglandin E1-induced hyperactivated sperm motility. One of the hit compounds is a potent CatSper inhibitor with high selectivity for CatSper over hCav1.2, hNav1.5, moderate selectivity over hSlo3 and hERG, and low cytotoxicity and is therefore the most promising inhibitor identified in this study. These new CatSper blockers serve as useful starting points for chemical probe development and drug discovery efforts.
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Affiliation(s)
- Erick J. Carlson
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Rawle Francis
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Yutong Liu
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Ping Li
- Department of Obstetrics and GynecologyWashington University School of Medicine425 S. Euclid AvenueSt. LouisMO 63110USA
| | - Maximilian Lyon
- Department of Obstetrics and GynecologyWashington University School of Medicine425 S. Euclid AvenueSt. LouisMO 63110USA
| | - Celia M. Santi
- Department of Obstetrics and GynecologyWashington University School of Medicine425 S. Euclid AvenueSt. LouisMO 63110USA
| | - Derek J. Hook
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Jon E. Hawkinson
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Gunda I. Georg
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
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Jeschke JK, Biagioni C, Schierling T, Wagner IV, Börgel F, Schepmann D, Schüring A, Kulle AE, Holterhus PM, von Wolff M, Wünsch B, Nordhoff V, Strünker T, Brenker C. The Action of Reproductive Fluids and Contained Steroids, Prostaglandins, and Zn 2+ on CatSper Ca 2+ Channels in Human Sperm. Front Cell Dev Biol 2021; 9:699554. [PMID: 34381781 PMCID: PMC8350739 DOI: 10.3389/fcell.2021.699554] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/23/2021] [Indexed: 12/16/2022] Open
Abstract
The sperm-specific Ca2+ channel CatSper registers chemical cues that assist human sperm to fertilize the egg. Prime examples are progesterone and prostaglandin E1 that activate CatSper without involving classical nuclear and G protein-coupled receptors, respectively. Here, we study the action of seminal and follicular fluid as well of the contained individual prostaglandins and steroids on the intracellular Ca2+ concentration of sperm from donors and CATSPER2-deficient patients that lack functional CatSper channels. We show that any of the reproductive steroids and prostaglandins evokes a rapid Ca2+ increase that invariably rests on Ca2+ influx via CatSper. The hormones compete for the same steroid- and prostaglandin-binding site to activate the channel, respectively. Analysis of the hormones’ structure–activity relationship highlights their unique pharmacology in sperm and the chemical features determining their effective properties. Finally, we show that Zn2+ suppresses the action of steroids and prostaglandins on CatSper, which might prevent premature prostaglandin activation of CatSper in the ejaculate, aiding sperm to escape from the ejaculate into the female genital tract. Altogether, our findings reinforce that human CatSper serves as a promiscuous chemosensor that enables sperm to probe the varying hormonal microenvironment prevailing at different stages during their journey across the female genital tract.
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Affiliation(s)
- Janice K Jeschke
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Cristina Biagioni
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Tobias Schierling
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Isabel Viola Wagner
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany.,Department of Pediatrics, University Hospital Lübeck, University of Lübeck, Lübeck, Germany
| | - Frederik Börgel
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Dirk Schepmann
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Andreas Schüring
- UKM Kinderwunschzentrum, University Hospital Münster, Münster, Germany
| | - Alexandra E Kulle
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Christian-Albrechts-University, Kiel, Germany
| | - Paul Martin Holterhus
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Christian-Albrechts-University, Kiel, Germany
| | - Michael von Wolff
- Division of Gynecological Endocrinology and Reproductive Medicine, University Women's Hospital, Bern, Switzerland
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Verena Nordhoff
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Timo Strünker
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany.,Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany
| | - Christoph Brenker
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
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9
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The Role of Zinc in Male Fertility. Int J Mol Sci 2020; 21:ijms21207796. [PMID: 33096823 PMCID: PMC7589359 DOI: 10.3390/ijms21207796] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/14/2020] [Accepted: 10/20/2020] [Indexed: 12/18/2022] Open
Abstract
Several studies proposed the importance of zinc ion in male fertility. Here, we describe the properties, roles and cellular mechanisms of action of Zn2+ in spermatozoa, focusing on its involvement in sperm motility, capacitation and acrosomal exocytosis, three functions that are crucial for successful fertilization. The impact of zinc supplementation on assisted fertilization techniques is also described. The impact of zinc on sperm motility has been investigated in many vertebrate and invertebrate species. It has been reported that Zn2+ in human seminal plasma decreases sperm motility and that Zn2+ removal enhances motility. Reduction in the intracellular concentration of Zn2+ during epididymal transit allows the development of progressive motility and the subsequent hyper activated motility during sperm capacitation. Extracellular Zn2+ affects intracellular signaling pathways through its interaction with the Zn2+ sensing receptor (ZnR), also named GPR39. This receptor was found in the sperm tail and the acrosome, suggesting the possible involvement of Zn2+ in sperm motility and acrosomal exocytosis. Our studies showed that Zn2+ stimulates bovine sperm acrosomal exocytosis, as well as human sperm hyper-activated motility, were both mediated by GPR39. Zn2+ binds and activates GPR39, which activates the trans-membrane-adenylyl-cyclase (tmAC) to catalyze cAMP production. The NHE (Na+/H+-exchanger) is activated by cAMP, leading in increased pHi and activation of the sperm-specific Ca2+ channel CatSper, resulting in an increase in [Ca2+]i, which, together with HCO3−, activates the soluble adenylyl-cyclase (sAC). The increase in [cAMP]i activates protein kinase A (PKA), followed by activation of the Src-epidermal growth factor receptor-Pphospholipase C (Src-EGFR-PLC) cascade, resulting in inositol-triphosphate (IP3) production, which mobilizes Ca2+ from the acrosome, causing a further increase in [Ca2+]i and the development of hyper-activated motility. PKA also activates phospholipase D1 (PLD1), leading to F-actin formation during capacitation. Prior to the acrosomal exocytosis, PLC induces phosphadidylinositol-4,5-bisphosphate (PIP2) hydrolysis, leading to the release of the actin-severing protein gelsolin to the cytosol, which is activated by Ca2+, resulting in F-actin breakdown and the occurrence of acrosomal exocytosis.
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Dey S, Brothag C, Vijayaraghavan S. Signaling Enzymes Required for Sperm Maturation and Fertilization in Mammals. Front Cell Dev Biol 2019; 7:341. [PMID: 31921853 PMCID: PMC6930163 DOI: 10.3389/fcell.2019.00341] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 12/03/2019] [Indexed: 12/18/2022] Open
Abstract
In mammals, motility and fertilizing ability of spermatozoa develop during their passage through the epididymis. After ejaculation, sperm undergo capacitation and hyperactivation in the female reproductive tract - a motility transition that is required for sperm penetration of the egg. Both epididymal initiation of sperm motility and hyperactivation are essential for male fertility. Motility initiation in the epididymis and sperm hyperactivation involve changes in metabolism, cAMP (cyclic adenosine mono-phosphate), calcium and pH acting through protein kinases and phosphatases. Despite this knowledge, we still do not understand, in biochemical terms, how sperm acquire motility in the epididymis and how motility is altered in the female reproductive tract. Recent data show that the sperm specific protein phosphatase PP1γ2, glycogen synthase kinase 3 (GSK3), and the calcium regulated phosphatase calcineurin (PP2B), are involved in epididymal sperm maturation. The protein phosphatase PP1γ2 is present only in testis and sperm in mammals. PP1γ2 has a isoform-specific requirement for normal function of mammalian sperm. Sperm PP1γ2 is regulated by three proteins - inhibitor 2, inhibitor 3 and SDS22. Changes in phosphorylation of these three inhibitors and their binding to PP1γ2 are involved in initiation and activation of sperm motility. The inhibitors are phosphorylated by protein kinases, one of which is GSK3. The isoform GSK3α is essential for epididymal sperm maturation and fertility. Calcium levels dramatically decrease during sperm maturation and initiation of motility suggesting that the calcium activated sperm phosphatase (PP2B) activity also decreases. Loss of PP2B results in male infertility due to impaired sperm maturation in the epididymis. Thus the three signaling enzymes PP1γ2, GSK3, and PP2B along with the documented PKA (protein kinase A) have key roles in sperm maturation and hyperactivation. Significantly, all these four signaling enzymes are present as specific isoforms only in placental mammals, a testimony to their essential roles in the unique aspects of sperm function in mammals. These findings should lead to a better biochemical understanding of the basis of male infertility and should lead to novel approaches to a male contraception and managed reproduction.
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