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Epididymal maturation – a crucial step in the post-testicular sperm development
Postlerová, Pavla ; Pohlová, Alžběta ; Zigo, Michal ; Jonáková, Věra
Mammalian spermatozoa after their development in testis undergo the post-testicular maturation in epididymis where acquire their fertilization ability and competence of movement. The epididymis is tissue with very active fluid-absorbing and fluid-secreting activity. Epididymal fluid contains ions and small molecules, proteins, glycoproteins and enzymes. The surface of spermatozoa is exposed directly to the epididymal fluid, and the sperm plasma membrane is significantly changed. Some testicular proteins are altered, masked, or replaced by new proteins/glycoproteins of epididymal origin. Several proteins produced by epididymis have been described in various mammalian species and shown to be associated with spermatozoa suggesting a role in the sperm maturation and/or sperm-egg binding and fusion. We isolated proteins from fluid, tissue and sperm of boar epididymis, and separated them by chromatographic and electrophoretic methods. We searched for known proteins using panel of antibodies and tested proteins of epididymal fluid for binding abilities. In the epididymis, we found proteins described as proteins of seminal plasma and associated with the sperm surface, such as spermadhesins, beta-microseminoprotein and acrosin inhibitor. These proteins were detected in epididymal sperm, fluid and tissue. We showed that some epididymal proteins may bind the spermatozoa and change the binding sites on the sperm surface. We determined and identified some proteins from boar epididymal fluid with affinity to heparin, hyaluronan and zona pellucida glycoproteins. These phenomena indicate that epididymal fluid proteins bind to the sperm surface during epididymal maturation and might subsequently play role in the sperm capacitation or sperm-zona pellucida binding.
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Sperm protein profiles of different mammalian species
Pohlová, Alžběta ; Zigo, Michal ; Jonáková, Věra ; Postlerová, Pavla
Proteins are a substantial equipment of the spermatic cell; therefore, the characterization of sperm proteins is crucial for explanation of molecular mechanisms in the reproduction process. We isolated sperm proteins from different mammalian species - pig, bull, human, mouse, dog and cat. Extracted proteins were separated by SDS-electrophoresis and protein/glycoprotein profiles from epididymal or ejaculated sperm were compared. Additionally, we tested cross-reactivity of antibodies prepared to sperm boar proteins on spermatozoa of other mammalian species using immunofluorescent technique. Our future plan is to compare the protein profiles of sperm during their functional development (epididymal, ejaculated, capacitated) in various mammalian species and identify species-specific sperm proteins with zona pellucida binding activity.
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Biochemické motody jako nástroj pro studium proteinů v reprodukci
Postlerová, Pavla ; Zigo, Michal ; Pohlová, Alžběta ; Jonáková, Věra
Studium molekulárních mechanismů rerodukce je důležité pro pochopení tohoto děje. pro extrakci proteinů ze spermií využíváme různé přístupy a specializované kity, které izolují proteiny z různých částí a povrchu spermatické buňky. Proteiny z reprodukčních tekutin dělíme pomocí chromatografických metod. Charakterizaci a porovnání proteinů získaných odlišnými extrakčními metodami nebo proteinů různých savčích druhů a proteinů spermií, které jsou v rozdílných stádiích svého vývoje, provádíme pomocí SDS a 2D elektroforézy. Elektroforeticky separované proteiny přenesené na NC membránu využíváme pro detekci pomocí protilátek nebo k vazebnýcm studiím s biotinem značenými ligandy. Izolace proteinů z reprodukčních tkání a tekutin a jejich detekce pomocí protilátek je nezbytná pro určení původu proteinů reprodukčního traktu. Lokalizace proteinů na povrchu a uvnitř spermatických buněk a v sekreční tkáni reprodukčních orgánů studujeme pomocé imunofluorescenční mikroskopie. Cílená izolace určitých proteinů spermatické buňky, jejich lokalizace na spermiích nebo v tekutinách a tkáních reprodukčního traktu slouží jako nepostradatelné nástroje pro studium molekulárních mechanismů reprodukčního procesu.
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Estrogen receptor beta (ERβ) in testicular cells and sperm
Dostálová, Pavla ; Žatecká, Eva ; Děd, Lukáš ; Dorosh, Andriy ; Postlerová, Pavla ; Jonáková, Věra ; Dvořáková-Hortová, Kateřina ; Pěknicová, Jana
Estrogen is a steroid hormone that plays an important role during sperm development in the male and female reproductive tract. Estrogen signalling is a complex process that depends on cell milieu and presence of receptors. Thanks to the steroid nature of estrogens, they can pass through the plasmatic membrane and bind to the intracellular estrogen receptors (ERs). Within the cell, there are several pools of ERs. One of them is localized to the cell nucleus and their activation leads to direct or indirect binding to DNA and ultimately to alternation in gene expression (genomic pathway). Other pools of ERs are associated with plasma membrane or are located in cytosol. Activation of membrane associated ERs leads to rapid non-genomic responses. Nowadays, two classical estrogen receptors are known – ERα and ERβ. Since ERβ is a predominant variant in testes, we focused our study on expression of ERβ variants in murine testes and sperm. We detected two variants of ERβ at mRNA level in both, testes and sperm. These variants differ in 54 nucleotids within the ligand binding domain and this variability results in different affinity to estrogen. We analyzed individual testicular cell types (spermatogonia, spermatocytes, spermatids, Sertoli cells) by RT-qPCR. Our results suggest that both ERβ variants are coexpressed in the same cell type and may therefore interact together. This may have consequences in mediating of estrogen signalling. Moreover, ERβ is expressed more in the later stages of spermatogenesis suggesting the role of ERβ in these stages or alternatively in spermatozoa alone. At the protein level, we detected ERβ in nuclear, membrane and cytosolic fraction prepared from testicular tissue suggesting the involvement of both, genomic and non-genomic, pathways of estrogen signaling in testes. In sperm, anti-ERβ antibodies localized ERβ in acrosome region and tail which is in accordance with the known role of estrogen on capacitation, acrosome reaction and motility.
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Possible role of spermatogenic protein glyceraldehyde-3-phosphate dehydrogenase (GAPDHS) in mammalian sperm
Margaryan, Hasmik ; Dorosh, Andriy ; Čapková, Jana ; Postlerová, Pavla ; Philimonenko, Anatoly ; Hozák, Pavel ; Pěknicová, Jana
Sperm proteins are important for the structure and function of these specific, highly differentiated cells. Certain of these proteins play a role in sperm-egg recognition during primary or secondary binding at zona pellucida glycoprotein matrix. The aim of this study was to characterize the acrosomal sperm protein recognized by a monoclonal antibody (MoAb) Hs-8, prepared in our laboratory by immunization of BALB/c mice with human ejaculated sperm, and to test the possible role of this protein in gamete interaction. MoAb Hs-8 specifically labelled a 45 kDa protein from the sperm extract in the immunoblotting test. Sequence analysis identified this Hs-8 protein as GAPDHS. In order to perform a control tests, a commercial mouse anti-GAPDHS MoAb was applied. Both antibodies showed similar staining patterns using immunofluorescence labelling, transmission electron microscopy and immunoblot analysis. Moreover, both Hs-8 and commercial anti-GAPDHS antibodies blocked the secondary sperm-zona pellucida binding. Generally, GAPDHS was considered mainly as sperm-specific glycolytic enzyme involved in energy production during spermatogenesis and sperm motility and its role in the sperm head was unknown. In this study, we confirmed the potential additional role of GAPDHS as a binding protein that is involved in the sperm-zona pellucida interaction.
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The ubiquitin–proteasome system is involved in the regulation of activity of spermadhesin aqn1 and acrosin inhibitor, the two sperm surface proteins, during porcine fertilization
Jonáková, Věra ; Yi, Y.J. ; Postlerová, Pavla ; Pěknicová, Jana
The spermadhesin AQN1and acrosin inhibitor (AI/SPINK2) proteins bind to the sperm plasma membrane at ejaculation. The AQN1 has been implicated in sperm binding to zona pellucida (ZP) of the oocyte as well as in sperm interactions with the epithelium of the oviductal sperm reservoir. The SPINK2 protects spermatozoa from proteolytic degradation during their trip up the female genital tract toward the oocyte. This study examined the role of two components of the 19S proteasome regulatory complex, the ubiquitin C-terminal hydrolase UCHL3 and PSMD8 in the AQN1-mediated boar sperm binding to zona pellucida. Interaction of PSMD4 subunit with the acrosomal surface-associated acrosin inhibitor AI/SPINK2 provided another line of evidence for the presence of 26S proteasomes on the sperm surface. Detection of the ubiquitinated forms of SPINK2 supports the hypothesis that SPINK2 activity is controlled by ubiquitin-proteasome system (UPS). The activity of the porcine AQN1, and thus the efficiency of sperm-oocyte recognition/binding, may be controlled by elements of the sperm surface-bound UPS, in particular by UCHL3, and by proteasomal regulatory complex subunit PSMD8. Ubiquitinated isoforms of AQN1 were also detected in boar sperm extracts. The UCHL inhibitor ubiquitin aldehyde and the antibodies against UCHL3 or PSMD8 increased the rate of sperm-ZP penetration and polyspermy during porcine in vitro fertilization (IVF). In contrast, the addition of recombinant UCHL3 to fertilization medium significantly reduced polyspermy rates, while maintaining satisfactory rate of monospermic fertilization (~50%). These results are significant for production agriculture. The high level of polyspermy that hinders porcine IVF for commercial embryo transfer could be mitigated by the modulation of the UCHL3 and/or PSMD8 activity.
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Panel of monoclonal antibodies – alternative tool For monitoring of sperm–zona pellucida receptors localization and identification
Zigo, Michal ; Dorosh, Andriy ; Pohlová, Alžběta ; Jonáková, Věra ; Šulc, Miroslav ; Maňásková-Postlerová, Pavla
Primary binding of the sperm to the zona pellucida (ZP) is one of the many steps necessary for successful fertilization in all sexually reproducing species. Sperm bind ZP by means of membrane receptors which recognize carbohydrate moieties on ZP glycoproteins according to a well-precised sequential process. Primary-binding receptors are localized throughout the acrosomal region of the sperm surface of which many have been disclosed in various mammals. For the monitoring sperm-zona pellucida receptors in terms of localization and characterization - panel of monoclonal antibodies against proteins from the sperm surface was prepared. Antibodies were screened by immunofluorescence and Western blotting for protein localizations and competence of antibodies, respectively. Antibodies recognizing proteins localized on the sperm head and simultaneously detected by Western blot were further studied by means of immunolocalization in reproductive tissues and fluids, binding to ZP, immunoprecipitation and protein identification using MS analysis. Out of 17 prepared antibodies, 8 antibodies were simultaneously recognizing proteins localized on the sperm head and detecting proteins of interest by Western blotting. Further only 3 antibodies recognized proteins which also coincided in binding to ZP. These 3 antibodies were used for immunoprecipitation, and further protein identification of immunoprecipitates revealed that the antibodies distinguish acrosin precursor, RAB2A protein, and lactadherin P47. Acrosin and lactadherin P47 have been already detected on the sperm surface and their physiological functions in reproduction have been proposed. To our knowledge, this is the first time RAB2A has been found on the surface of sperm and its physiological function in the process of fertilization remains undisclosed.
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Enzymatic and inhibiting activity in boar epididymal fluid
Davidová, Nina ; Ren, Š. ; Liberda, J. ; Jonáková, Věra ; Maňásková-Postlerová, Pavla
Sperm maturation, represents a key step in the reproduction process. Spermatozoa, particularly the plasma membrane, are exposed to epididymal fluid (EF) components representing the natural environment essential for their post-testicular maturation. Changes in the sperm membrane proteins are influenced by proteolytic and glycosidic enzymes present in the EF. Accordingly, the occurrence of inhibitors in this reproductive organ is very important for the regulation of sperm membrane protein processing. In present study, we monitored protease and glycosidase activities, and inhibitors of metallo- and serine proteinases in boar EF. Additionally, we studied acrosin inhibitor in fluid, spermatozoa and tissue along the epididymis. We chromatographically separated boar EF into several fractions. These fractions were subjected to SDS-electrophoresis and the separated proteins were either studied by zymographic methods or transferred to nitrocellulose membranes for detection of metallo- and serine proteinases and their inhibitors, and acrosin inhibitor by specific antibody, respectively. Acrosin inhibitor was monitored also in the sperm and tissue of the boar epididymis. In boar epididymal fluid, several metallo- and serine proteinases with different molecular masses, and inhibitors of metalloproteinase MMP-9 and acrosin were found. We measured strong activity of mannosidase in this fluid. Using specific antibody, we registered the increasing signal of acrosin inhibitor from caput to cauda epididymis in the spermatozoa, fluid and also tissue. Proteinases and their inhibitors in reproductive fluids may play a significant role in reproduction processes. Especially, acrosin inhibitor in the reproductive tract inactivates prematurely released sperm acrosin and protects spermatozoa and reproductive epithelium against proteolytic degradation. High mannosidase activity in boar EF suggests evident role of mannose structures in the sperm interaction during reproductive events.
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Povrchové proteiny spermie: původ, biochemické vlastnosti a úloha v reprodukci
Jonáková, Věra ; Postlerová, Pavla ; Tichá, M. ; Pěknicová, Jana
Proteiny semenné plasmy se váží na povrch spermie při ejakulaci a modulují vlastnosti spermie při reprodukci. Kančí spermadhesiny (AQN, AWN, PSP) jsou sekretovány hlavně semenými vaky (SV), ale jejich mRNA byla nalezena také v cauda epididymis a prostatě. Pomocí specifických protilátek PSP I a PSP II proteiny byly imunodetekovány na blotu v tkáňových extraktech cauda epididymis, prostatě, SV, a nepřímou imunofluorescencí v sekreční tkáni cauda epididymis, prostatě, SV. Lokalizovali jsme PSP spermadhesiny na epididymálnícj a ejakulovaných spermiích. PSP proteiny jsou produkovány SV, prostatou a také nadvarletem. Charakterizace proteinů semenné plasmy exprimovaných v jednotlivých reprodukčních orgánech napomůže pochopit jejich úlohu v reprodukci
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Role povrchových proteinů v reprodukci
Jonáková, Věra ; Postlerová, Pavla ; Tichá, M. ; Pěknicová, Jana
Během ejakulace se proteiny semenné plasmy navazují na povrch spermie a tvoří povrchové proteiny spermie, které mohou změnit vazebné vlastnosti spermie. DQH povrchový protein spermie vykazuje afinitu k oviduktálnímu epitelu a glykoproteinům zona pellucida (ZP). DQH mRNA byla detekována v semenných vacích (SV). DQH byl imunodetekován monoklonálními protilátkami (Mabs)v extraktu a tekutině i na tkáňových řezech SV vaků a na plasmatické membráně akrosomu ejakulovaných spermií. Výsledky potvrzují schopnost DQH proteinu se vázat na povrch spermie při ejakulaci, účast při tvorbě rezervoáru spermií v prasečím oviduktu. Spermie preinkubované s Mabs proti DQH proteinu před koinkubací s vajíčkem redukují vazbu spermie k vajíčku. Pro primární vazbu spermie s ZP glykoproteiny vajíčka je důležitý intaktní DQH protein na povrchu spermie.
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