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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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The stallion sperm acrosome: Considerations from a research and clinical perspective. Theriogenology 2023; 196:121-149. [PMID: 36413868 DOI: 10.1016/j.theriogenology.2022.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/02/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022]
Abstract
During the fertilization process, the interaction between the sperm and the oocyte is mediated by a process known as acrosomal exocytosis (AE). Although the role of the sperm acrosome on fertilization has been studied extensively over the last 70 years, little is known about the molecular mechanisms that govern acrosomal function, particularly in species other than mice or humans. Even though subfertility due to acrosomal dysfunction is less common in large animals than in humans, the evaluation of sperm acrosomal function should be considered not only as a complementary but a routine test when individuals are selected for breeding potential. This certainly holds true for stallions, which might display lower levels of fertility in the face of "acceptable" sperm quality parameters determined by conventional sperm assays. Nowadays, the use of high throughput technologies such as flow cytometry or mass spectrometry-based proteomic analysis is commonplace in the research arena. Such techniques can also be implemented in clinical scenarios of males with "idiopathic" subfertility. The current review focuses on the sperm acrosome, with particular emphasis on the stallion. We aim to describe the physiological events that lead to the acrosome formation within the testis, the role of very specific acrosomal proteins during AE, the methods to study the occurrence of AE under in vitro conditions, and the potential use of molecular biology techniques to discover new markers of acrosomal function and subfertility associated with acrosomal dysfunction in stallions.
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Bowker Z, Goldstein S, Breitbart H. Protein acetylation protects sperm from spontaneous acrosome reaction. Theriogenology 2022; 191:231-238. [PMID: 35998406 DOI: 10.1016/j.theriogenology.2022.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 07/27/2022] [Accepted: 08/03/2022] [Indexed: 10/15/2022]
Abstract
In order to penetrate the egg, spermatozoa must undergo the acrosome reaction in close proximity to the egg. This process can take place only after a series of biochemical changes in the sperm, collectively termed capacitation, occur in the female reproductive tract. Sperm cells can undergo spontaneous-acrosome reaction(sAR) before reaching the vicinity of the egg, preventing successful fertilization. Several mechanisms were shown to protect sperm from undergoing sAR, and all of them are involved in proper capacitation. Here, we describe the involvement of protein acetylation in the mechanism that protects bovine spermatozoa from sAR. Incubation of bovine sperm under non-capacitation conditions revealed a strong increase in sAR that was significantly reduced in the presence of deacetylase inhibitors. Protein kinase A (PKA) is an essential key enzyme in sperm capacitation, and its inhibition results in high sAR. The reduction in sAR by hyperacetylation was independent of PKA activity. We previously demonstrated that calmodulin-kinase II (CaMKII) activity protects sperm from sAR, and here we show that its activity is essential for reduction in sAR by hyperacetylation. We further show that the 'exchange protein directly activated by Camp' (EPAC) mediates both protein lysine acetylation and the reduced rate of sAR caused by hyperacetylation. In conclusion, these results suggest a PKA-independent and EPAC-CaMKII dependent hyperacetylation mechanism that protects sperm from sAR.
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Affiliation(s)
- Z Bowker
- The Mina & Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - S Goldstein
- The Mina & Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - H Breitbart
- The Mina & Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 5290002, Israel.
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Zhao YY, Zhang LJ, Liang XY, Zhang XC, Chang JR, Shi M, Liu H, Zhou Y, Sun Z, Zhao YF. Pyruvate Upregulates Hepatic FGF21 Expression by Activating PDE and Inhibiting cAMP–Epac–CREB Signaling Pathway. Int J Mol Sci 2022; 23:ijms23105490. [PMID: 35628302 PMCID: PMC9141208 DOI: 10.3390/ijms23105490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 02/01/2023] Open
Abstract
Fibroblast growth factor 21 (FGF21) functions as a polypeptide hormone to regulate glucose and lipid metabolism, and its expression is regulated by cellular metabolic stress. Pyruvate is an important intermediate metabolite that acts as a key hub for cellular fuel metabolism. However, the effect of pyruvate on hepatic FGF21 expression and secretion remains unknown. Herein, we examined the gene expression and protein levels of FGF21 in human hepatoma HepG2 cells and mouse AML12 hepatocytes in vitro, as well as in mice in vivo. In HepG2 and AML12 cells, pyruvate at concentrations above 0.1 mM significantly increased FGF21 expression and secretion. The increase in cellular cAMP levels by adenylyl cyclase activation, phosphodiesterase (PDE) inhibition and 8-Bromo-cAMP administration significantly restrained pyruvate-stimulated FGF21 expression. Pyruvate significantly increased PDE activities, reduced cAMP levels and decreased CREB phosphorylation. The inhibition of exchange protein directed activated by cAMP (Epac) and cAMP response element binding protein (CREB) upregulated FGF21 expression, upon which pyruvate no longer increased FGF21 expression. The increase in plasma pyruvate levels in mice induced by the intraperitoneal injection of pyruvate significantly increased FGF21 gene expression and PDE activity with a reduction in cAMP levels and CREB phosphorylation in the mouse liver compared with the control. In conclusion, pyruvate activates PDEs to reduce cAMP and then inhibits the cAMP–Epac–CREB signaling pathway to upregulate FGF21 expression in hepatocytes.
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Denisenko V, Chistyakova I, Volkova N, Volkova L, Iolchiev B, Kuzmina T. The Modulation of Functional Status of Bovine Spermatozoa by Progesterone. Animals (Basel) 2021; 11:ani11061788. [PMID: 34203892 PMCID: PMC8232648 DOI: 10.3390/ani11061788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/10/2021] [Accepted: 06/10/2021] [Indexed: 12/18/2022] Open
Abstract
Simple Summary Progesterone is an endogenous steroid hormone, which can induce capacitation and/or acrosome reactions in semen of certain mammalian species. Our study aimed to investigate the effect of progesterone on the functional status of fresh bovine spermatozoa using a chlortetracycline fluorescent probe. Results showed that heparin induced capacitation in spermatozoa incubated with or without progesterone. The destruction of microfilaments by an inhibitor of cytochalasin D blocked the stimulating effect of heparin. Steroid hormone in mixture with prolactin stimulated the acrosome reaction in spermatozoa, which was blocked by an inhibitor of microtubule polymerization (nocodazole). At the acrosome stage, prolactin provided the undergoing of acrosome reaction in male gametes. This effect was noted both in the presence and absence of progesterone and inhibited by nocodazole. The supplementation of dibutyryl cyclic adenosine monophosphate during the acrosome reaction to progesterone-untreated spermatozoa did not cause changes in proportion of acrosome-reacted cells. However, when progesterone was added during capacitation, a significant increase in the proportion of capacitated cells was noted, which was inhibited by nocodazole. Thus, progesterone under the action of prolactin and dibutyryl cyclic adenosine monophosphate determines the functional status of fresh spermatozoa, which indicates progesterone-modulating effect on the indicators of post-ejaculatory maturation of male gametes. Abstract The aim of this study is to identify the effects of progesterone (PRG) on the capacitation and the acrosome reaction in bovine spermatozoa. The fresh sperm samples were incubated with and without capacitation inductors (heparin, dibutyryl cyclic adenosine monophosphate (dbcAMP)), hormones (prolactin (PRL), PRG), inhibitors of microfilaments (cytochalasin D) and microtubules (nocodazole) during capacitation and acrosome reactions. The functional status of spermatozoa was examined using the chlortetracycline assay. Supplementation of heparin stimulated capacitation in the presence and absence of PRG. Cytochalasin D blocked the stimulating effect of heparin on capacitation. The addition of PRL during capacitation (without PRG) did not affect the functional status of spermatozoa, while in PRG-treated cells PRL stimulated the acrosome reaction. PRL (with and without PRG) increased the acrosome reaction in capacitated cells. These PRL-dependent effects were inhibited by nocodazole. During the acrosome reaction, in presence of dbcAMP, PRG decreased the proportion of acrosome-reacted cells compared to PRG-untreated cells. This effect in PRG-treated cells was canceled in the presence of nocodazole. In conclusion, PRG under the action of PRL and dbcAMP determines the changes in the functional status of native sperm cells, which indicates PRG modulating effect on the indicators of post-ejaculatory maturation of spermatozoa.
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Affiliation(s)
- Vitaly Denisenko
- Branch of Federal Research Center for Animal Husbandry Named after Academy Member L.K. Ernst, Russian Research Institute of Genetic and Breeding Farm Animals, 196601 Saint-Petersburg, Russia; (V.D.); (I.C.)
| | - Irena Chistyakova
- Branch of Federal Research Center for Animal Husbandry Named after Academy Member L.K. Ernst, Russian Research Institute of Genetic and Breeding Farm Animals, 196601 Saint-Petersburg, Russia; (V.D.); (I.C.)
| | - Natalia Volkova
- Federal Research Center for Animal Husbandry Named after Academy Member L.K. Ernst, 142132 Moscow, Russia; (N.V.); (L.V.); (B.I.)
| | - Ludmila Volkova
- Federal Research Center for Animal Husbandry Named after Academy Member L.K. Ernst, 142132 Moscow, Russia; (N.V.); (L.V.); (B.I.)
| | - Baylar Iolchiev
- Federal Research Center for Animal Husbandry Named after Academy Member L.K. Ernst, 142132 Moscow, Russia; (N.V.); (L.V.); (B.I.)
| | - Tatyana Kuzmina
- Branch of Federal Research Center for Animal Husbandry Named after Academy Member L.K. Ernst, Russian Research Institute of Genetic and Breeding Farm Animals, 196601 Saint-Petersburg, Russia; (V.D.); (I.C.)
- Correspondence: ; Tel.: +7-9213-92-19-47
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Mata-Martínez E, Sánchez-Tusie AA, Darszon A, Mayorga LS, Treviño CL, De Blas GA. Epac activation induces an extracellular Ca 2+ -independent Ca 2+ wave that triggers acrosome reaction in human spermatozoa. Andrology 2021; 9:1227-1241. [PMID: 33609309 DOI: 10.1111/andr.12989] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/10/2021] [Accepted: 02/17/2021] [Indexed: 01/02/2023]
Abstract
BACKGROUND The signaling pathways of the intracellular second messengers cAMP and Ca2+ play a crucial role in numerous physiological processes in human spermatozoa. One such process is the acrosome reaction (AR), which is necessary for spermatozoa to traverse the egg envelope and to expose a fusogenic membrane allowing the egg-sperm fusion. Progesterone and zona pellucida elicit an intracellular Ca2+ increase that is needed for the AR in the mammalian spermatozoa. This increase is mediated by an initial Ca2+ influx but also by a release from intracellular Ca2+ stores. It is known that intracellular Ca2+ stores play a central role in the regulation of [Ca2+ ]i and in the generation of complex Ca2+ signals such as oscillations and waves. In the human spermatozoa, it has been proposed that the cAMP analog and specific agonist of Epac 8-(p-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (2'-O-Me-cAMP) elicits an intracellular Ca2+ release involved in the AR. OBJECTIVE To identify the molecular entities involved in the Ca2+ mobilization triggered by 2'-O-Me-cAMP in human spermatozoa. MATERIALS AND METHODS In capacitated human spermatozoa, we monitored Ca2+ dynamics and the occurrence of the AR in real time using Fluo 3-AM and FM4-64 in a Ca2+ -free medium. RESULTS Epac activation by 2'-O-Me-cAMP induced a Ca2+ wave that started in the midpiece and propagated to the acrosome region. This Ca2+ response was sensitive to rotenone, CGP, xestospongin, NED-19, and thapsigargin, suggesting the participation of different ion transporters (mitochondrial complex I and Na+ /Ca2+ exchanger, inositol 3-phosphate receptors, two-pore channels and internal store Ca2+ -ATPases). DISCUSSION Our results suggest that Epac activation promotes a dynamic crosstalk between three different intracellular Ca2+ stores: the mitochondria, the redundant nuclear envelope, and the acrosome. CONCLUSION The Ca2+ wave triggered by Epac activation is necessary to induce the AR and to enhance the flagellar beat.
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Affiliation(s)
- Esperanza Mata-Martínez
- Laboratorio de Fusión de Membranas y Exocitosis Acrosomal, Instituto de Histología y Embriología Dr. Mario H. Burgos (IHEM), Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina
| | - Ana Alicia Sánchez-Tusie
- Laboratorio de Fisiología Celular y Molecular, Departamento de Investigación Biomédica, Facultad de Medicina, Universidad Autónoma de Querétaro, México
| | - Alberto Darszon
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Morelos, México
| | - Luis S Mayorga
- Laboratorio de Fusión de Membranas y Exocitosis Acrosomal, Instituto de Histología y Embriología Dr. Mario H. Burgos (IHEM), Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Claudia L Treviño
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Morelos, México
| | - Gerardo A De Blas
- Laboratorio de Fusión de Membranas y Exocitosis Acrosomal, Instituto de Histología y Embriología Dr. Mario H. Burgos (IHEM), Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina.,Laboratorio de Teleanálisis e Investigación Traslacional, Área Farmacología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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Finkelstein M, Etkovitz N, Breitbart H. Ca 2+ signaling in mammalian spermatozoa. Mol Cell Endocrinol 2020; 516:110953. [PMID: 32712383 DOI: 10.1016/j.mce.2020.110953] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 06/08/2020] [Accepted: 07/20/2020] [Indexed: 02/06/2023]
Abstract
Calcium is an essential ion which regulates sperm motility, capacitation and the acrosome reaction (AR), three processes necessary for successful fertilization. The AR enables the spermatozoon to penetrate into the egg. In order to undergo the AR, the spermatozoon must reside in the female reproductive tract for several hours, during which a series of biochemical transformations takes place, collectively called capacitation. An early event in capacitation is relatively small elevation of intracellular Ca2+ (in the nM range) and bicarbonate, which collectively activate the soluble adenylyl cyclase to produce cyclic-AMP; c-AMP activates protein kinase A (PKA), leading to indirect tyrosine phosphorylation of proteins. During capacitation, there is an increase in the membrane-bound phospholipase C (PLC) which is activated prior to the AR by relatively high increase in intracellular Ca2+ (in the μM range). PLC catalyzes the hydrolysis of phosphatidyl-inositol-4,5-bisphosphate (PIP2) to diacylglycerol and inositol-trisphosphate (IP3), leading to activation of protein kinase C (PKC) and the IP3-receptor. PKC activates a Ca2+- channel in the plasma membrane, and IP3 activates the Ca2+- channel in the outer acrosomal membrane, leading to Ca2+ depletion from the acrosome. As a result, the plasma-membrane store-operated Ca2+ channel (SOCC) is activated to increase cytosolic Ca2+ concentration, enabling completion of the acrosome reaction. The hydrolysis of PIP2 by PLC results in the release and activation of PIP2-bound gelsolin, leading to F-actin dispersion, an essential step prior to the AR. Ca2+ is also involved in the regulation of sperm motility. During capacitation, the sperm develops a unique motility pattern called hyper-activated motility (HAM) which is essential for successful fertilization. The main Ca2+-channel that mediates HAM is the sperm-specific CatSper located in the sperm tail.
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Affiliation(s)
| | - Nir Etkovitz
- Sperm Bank, Sheba Hospital, Tel-Hashomer, Israel
| | - Haim Breitbart
- The Mina & Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 5290002, Israel.
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Wang T, Young S, Krenz H, Tüttelmann F, Röpke A, Krallmann C, Kliesch S, Zeng XH, Brenker C, Strünker T. The Ca 2+ channel CatSper is not activated by cAMP/PKA signaling but directly affected by chemicals used to probe the action of cAMP and PKA. J Biol Chem 2020; 295:13181-13193. [PMID: 32703901 DOI: 10.1074/jbc.ra120.013218] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 07/21/2020] [Indexed: 12/14/2022] Open
Abstract
The sperm-specific Ca2+ channel CatSper (cation channel of sperm) controls the influx of Ca2+ into the flagellum and, thereby, the swimming behavior of sperm. A hallmark of human CatSper is its polymodal activation by membrane voltage, intracellular pH, and oviductal hormones. Whether CatSper is also activated by signaling pathways involving an increase of cAMP and ensuing activation of PKA is, however, a matter of controversy. To shed light on this question, we used kinetic ion-sensitive fluorometry, patch-clamp recordings, and optochemistry to study transmembrane Ca2+ flux and membrane currents in human sperm from healthy donors and from patients that lack functional CatSper channels. We found that human CatSper is neither activated by intracellular cAMP directly nor indirectly by the cAMP/PKA-signaling pathway. Instead, we show that nonphysiological concentrations of cAMP and membrane-permeable cAMP analogs used to mimic the action of intracellular cAMP activate human CatSper from the outside via a hitherto-unknown extracellular binding site. Finally, we demonstrate that the effects of common PKA inhibitors on human CatSper rest predominantly, if not exclusively, on off-target drug actions on CatSper itself rather than on inhibition of PKA. We conclude that the concept of an intracellular cAMP/PKA-activation of CatSper is primarily based on unspecific effects of chemical probes used to interfere with cAMP signaling. Altogether, our findings solve several controversial issues and reveal a novel ligand-binding site controlling the activity of CatSper, which has important bearings on future studies of cAMP and Ca2+ signaling in sperm.
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Affiliation(s)
- Tao Wang
- Institute of Life Science and School of Life Science, Nanchang University, Nanchang, Jiangxi, China; Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Samuel Young
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Henrike Krenz
- Institute of Medical Informatics, University of Münster, Münster, Germany
| | - Frank Tüttelmann
- Institute of Human Genetics, University of Münster, Münster, Germany
| | - Albrecht Röpke
- Institute of Human Genetics, University of Münster, Münster, Germany
| | - Claudia Krallmann
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Sabine Kliesch
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Xu-Hui Zeng
- Institute of Life Science and School of Life Science, Nanchang University, Nanchang, Jiangxi, China.
| | - Christoph Brenker
- 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.
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