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Müller K, Müller P, Lui F, Kroh PD, Braun BC. Porcine spermadhesin AQN-3 binds to negatively charged phospholipids. Chem Phys Lipids 2023; 254:105306. [PMID: 37156322 DOI: 10.1016/j.chemphyslip.2023.105306] [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: 03/15/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 05/10/2023]
Abstract
The spermadhesin AQN-3 is a major component of porcine seminal plasma. While various studies suggest that this protein binds to boar sperm cells, its attachment to the cells is poorly understood. Therefore, the capacity of AQN-3 to interact with lipids was investigated. For that purpose, AQN-3 was recombinantly expressed in E. coli and purified via the included His-tag. Characterizing the quaternary structure by size exclusion chromatography revealed that recombinant AQN-3 (recAQN-3) is largely present as multimer and/or aggregate. To determine the lipid specificity of recAQN-3, a lipid stripe method and a multilamellar vesicle (MLV)-based binding assay were used. Both assays show that recAQN-3 selectively interacts with negatively charged lipids, like phosphatidic acid, phosphatidylinositol phosphates, and cardiolipin. No interaction was observed with phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, or cholesterol. The affinity to negatively charged lipids can be explained by electrostatic interactions because binding is partly reversed under high-salt condition. However, more factors have to be assumed like hydrogen bonds and/or hydrophobic forces because the majority of bound molecules was not released by high salt. To confirm the observed binding behavior for the native protein, porcine seminal plasma was incubated with MLVs comprising phosphatidic acid or phosphatidyl-4,5-bisphosphate. Attached proteins were isolated, digested, and analyzed by mass spectrometry. Native AQN-3 was detected in all samples analyzed and was - besides AWN - the most abundant protein. It remains to be investigated whether AQN-3, together with other sperm associated seminal plasma proteins, acts as decapacitation factor by targeting negative lipids with signaling or other functional roles in fertilization.
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Affiliation(s)
- Karin Müller
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, D-10315 Berlin, Germany.
| | - Peter Müller
- Faculty of Life Sciences, Department of Biology, Humboldt University Berlin, Invalidenstrasse 42, 10115 Berlin, Germany
| | - Fan Lui
- Mass spectrometry, Leibniz Institute of Molecular Pharmacology, Robert-Rössle-Straße 10, D-13125 Berlin, Germany
| | - Pascal D Kroh
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, D-10315 Berlin, Germany
| | - Beate C Braun
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, D-10315 Berlin, Germany.
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Kroh PD, Braun BC, Lui F, Müller P, Müller K. Boar spermadhesin AWN: Novel insights in its binding behavior and localization on sperm. Biol Reprod 2022; 106:775-791. [PMID: 35020825 DOI: 10.1093/biolre/ioab244] [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: 04/19/2021] [Revised: 11/16/2021] [Accepted: 01/05/2022] [Indexed: 11/14/2022] Open
Abstract
As a major spermadhesin first found in the seminal plasma of boars, AWN is described to fulfil a variety of reproduction related tasks. Although being the best investigated boar spermadhesin, information about its interaction with membranes is inconsistent. In this regard, previous reports locate AWN either inside or on the surface of sperm cells and at different regions, depending on the method and antibody used. Here, we localize native AWN in/on epididymal, ejaculated, capacitated and acrosome-reacted boar sperm using epifluorescence and electron microscopy, as well as an analysis of potential lipid binding partners of native and recombinant AWN. By applying a custom-made anti-AWN antibody, localization of AWN in the equatorial segment of ejaculated, capacitated and acrosome-reacted boar sperm was discovered. Electron microscopy showed that AWN is localized both on the sperm surface and on the cytoplasmic side of the plasma membrane, and in close vicinity to the nuclear and both acrosomal membranes of sperm. Analysis of epididymal sperm indicated migration of AWN from the retral postacrosomal part to the equatorial segment during the epididymal passage. In contrast to hypotheses claiming a specific association of AWN to phosphatidylethanolamine and in line with our previous study describing an interaction with phosphatidic acid, the current results show a rather electrostatically-driven binding mechanism of AWN to negative lipids. In conclusion, this work provides new insights into the arrangement of AWN in the equatorial segment that suggest a possible role in sperm-oocyte fusion.
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Affiliation(s)
- Pascal D Kroh
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Beate C Braun
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Fan Lui
- Mass Spectrometry, Leibniz Research Institute for Molecular Pharmacology, Berlin, Germany
| | - Peter Müller
- Department of Biology/Biophysics, Humboldt University of Berlin, Berlin, Germany
| | - Karin Müller
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
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Zhao Y, Vanderkooi S, Kan FWK. The role of oviduct-specific glycoprotein (OVGP1) in modulating biological functions of gametes and embryos. Histochem Cell Biol 2022; 157:371-388. [PMID: 34993641 PMCID: PMC8979936 DOI: 10.1007/s00418-021-02065-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2021] [Indexed: 01/13/2023]
Abstract
Diverse lines of evidence indicate that the mammalian oviduct makes important contributions to the complex process of reproduction other than being simply a conduit for the transport of gametes and embryos. The cumulative synthesis and transport of proteins secreted by oviductal secretory cells into the oviductal lumen create a microenvironment supporting important reproductive events, including sperm capacitation, fertilization, and early embryo development. Among the components that have been identified in the oviductal fluid is a family of glycosylated proteins known collectively as oviduct-specific glycoprotein (OVGP1) or oviductin. OVGP1 has been identified in several mammalian species, including humans. The present review summarizes the work carried out, in various mammalian species, by many research groups revealing the synthesis and secretion of OVGP1, its fate in the female reproductive tract upon secretion by the oviductal epithelium, and its role in modulating biological functions of gametes and embryos. The production and functions of recombinant human OVGP1 and recombinant OVGP1 of other mammalian species are also discussed. Some of the findings obtained with immunocytochemistry will be highlighted in the present review. It is hoped that the findings obtained from recent studies carried out with recombinant OVGP1 from various species will rekindle researchers’ interest in pursuing further the role of the oviductal microenvironment, of which OVGP1 is a major component, in contributing to the successful occurrence of early reproductive events, and the potential use of OVGP1 in improving the current assisted reproductive technology in alleviating infertility.
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Affiliation(s)
- Yuewen Zhao
- Department of Biomedical and Molecular Sciences, Faculty of Health Sciences, Queen's University, Kingston, ON, K7L 3N, Canada
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics, Gynecology and Reproductive Sciences, Yale Fertility Center, Yale University, Orange, CT, 06477, USA
| | - Sydney Vanderkooi
- Department of Biomedical and Molecular Sciences, Faculty of Health Sciences, Queen's University, Kingston, ON, K7L 3N, Canada
| | - Frederick W K Kan
- Department of Biomedical and Molecular Sciences, Faculty of Health Sciences, Queen's University, Kingston, ON, K7L 3N, Canada.
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Schröter F, Müller K, Müller P, Krause E, Braun BC. Recombinant expression of porcine spermadhesin AWN and its phospholipid interaction: Indication for a novel lipid binding property. Reprod Domest Anim 2017; 52:585-595. [PMID: 28326614 DOI: 10.1111/rda.12953] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/07/2017] [Indexed: 01/05/2023]
Abstract
AWN is a porcine (Sus scrofa domestica) seminal plasma protein and has been linked to a variety of processes related to fertilization. To acquire the protein in sufficient amount and purity for functional studies, we established its recombinant expression in E. coli and a three-step purification protocol based on different chromatographies. The test for AWN-phospholipid interaction revealed phosphatidic acid and cardiolipin as potential binding partners. As phosphatidic acid is surmised to play a role in cation-induced membrane destabilization and fusion events, we propose a membrane protective function of the presented binding affinity. Further studies with recombinant AWN will allow new insights into the mechanism of sperm-spermadhesin interaction and might provide new approaches for artificial reproduction techniques.
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Affiliation(s)
- F Schröter
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - K Müller
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - P Müller
- Department of Biology/Biophysics, Humboldt University of Berlin, Berlin, Germany
| | - E Krause
- Department Mass Spectrometry, Leibniz Institute for Molecular Pharmacology, Berlin, Germany
| | - B C Braun
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
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Hribal R, Hachen A, Jewgenow K, Zahmel J, Fernandez-Gonzalez L, Braun BC. The influence of recombinant feline oviductin on different aspects of domestic cat (Felis catus) IVF and embryo quality. Theriogenology 2014; 82:742-9. [PMID: 25023298 DOI: 10.1016/j.theriogenology.2014.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/21/2014] [Accepted: 06/05/2014] [Indexed: 11/25/2022]
Abstract
Oviductin is known to be a key player providing a convenient environment for the process of fertilization affecting this by direct interaction with oocytes and sperm. As in vitro embryo production in the context of assisted reproduction for endangered felids is still in the process of optimization, oviductin might be used to improve IVF results. Recombinant His-tagged feline oviductin was expressed by transformed Escherichia coli BL21DE3 cells. The protein was purified by immobilized metal ion affinity chromatography. The effect of the recombinant protein was characterized in three experiments: a hemizona assay for sperm binding analysis, the IVF outcome, and the relative mRNA expression levels in blastocysts after IVF. A significant higher number of bound sperm cells were found after incubation in oviductin. No significant effect on cleavage, morula, and blastocyst rates with or without oviductin incubation during IVF could be observed. However, the relative mRNA abundance of GJA1, a gene, whose expression level is known to be a marker of embryo quality, was significantly increased (P value less than 0.05) in blastocysts after oviductin treatment. In contrast to this, expression of OCT4, HSP70, DNMT1, DNMT3A, BAX, IGF1R, and GAPDH was not significantly affected. We assume that our recombinant oviductin in its current nonglycosylated form is able to enhance sperm binding. Despite of a missing significant effect on IVF outcome, embryo quality in terms of relative GJA1 expression is influenced positively. These promising results demonstrate the value of recombinant oviductin for the IVF in cats.
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Affiliation(s)
- Romy Hribal
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.
| | - Alexandra Hachen
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Katarina Jewgenow
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Jennifer Zahmel
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | | | - Beate C Braun
- Department Reproduction Biology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
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