Dynamic regulation of sperm interactions with the zona pellucida prior to and after fertilisation

2013 ◽  
Vol 25 (1) ◽  
pp. 26 ◽  
Author(s):  
B. M. Gadella

Recent findings have refined our thinking on sperm interactions with the cumulus–oocyte complex (COC) and our understanding of how, at the molecular level, the sperm cell fertilises the oocyte. Proteomic analyses has identified a capacitation-dependent sperm surface reordering that leads to the formation of functional multiprotein complexes involved in zona–cumulus interactions in several mammalian species. During this process, multiple docking of the acrosomal membrane to the plasma membrane takes place. In contrast with the dogma that the acrosome reaction is initiated when spermatozoa bind to the zona pellucida (ZP), it has been established recently that, in mice, the fertilising spermatozoon initiates its acrosome reaction during its voyage through the cumulus before it reaches the ZP. In fact, even acrosome-reacted mouse spermatozoa collected from the perivitelline space can fertilise another ZP-intact oocyte. The oviduct appears to influence the extracellular matrix properties of the spermatozoa as well as the COC. This may influence sperm binding and penetration of the cumulus and ZP, and, in doing so, increase monospermic while decreasing polyspermic fertilisation rates. Structural analysis of the ZP has shed new light on how spermatozoa bind and penetrate this structure and how the cortical reaction blocks sperm–ZP interactions. The current understanding of sperm interactions with the cumulus and ZP layers surrounding the oocyte is reviewed with a special emphasis on the lack of comparative knowledge on this topic in humans, as well as in most farm mammals.

Zygote ◽  
1999 ◽  
Vol 7 (2) ◽  
pp. 105-111 ◽  
Author(s):  
R. D. Moreno ◽  
M. Hoshi ◽  
C. Barros

Acrosin is a serine protease located within mammalian acrosome as inactive proacrosin. Sulphated polymers bind to proacrosin and acrosin, to a domain different from the active site. Upon binding, these polymers induce proacrosin activation and some of them, such as fucoidan, inhibit sperm binding to the zona pellucida. In this work we have studied the interaction of solubilised zona pellucida glycoproteins (ZPGs), heparin and ARIS (Acrosome Reaction Inducing Substance of Starfish) with boar and human acrosin. We have found that ARIS, solubilised ZPGs and fucoidan, but not heparin, inhibit the binding of the monoclonal antibody against human acrosin C5F10 to boar or human proacrosin. These results suggest that fucoidan, solubilised ZPGs and ARIS bind to a related domain on the proacrosin surface. Moreover, ARIS was able to induce human proacrosin activation. On the other hand, neither ARIS nor heparin from porcine intestinal mucosa or bovine lung induced hamster sperm acrosome reaction or sperm motility. Recent data showed that acrosin is involved in dispersal of the acrosomal matrix after acrosome reaction. Thus, the control of the ZPG glycan chains over proacrosin activation may regulate both sperm penetration rate and limited proteolysis of zona pellucida proteins.


1989 ◽  
Vol 92 (4) ◽  
pp. 713-722
Author(s):  
M.H. Vazquez ◽  
D.M. Phillips ◽  
P.M. Wassarman

We describe a solid-phase assay that has permitted further analysis of zona pellucida glycoprotein, ZP3, as sperm receptor and acrosome reaction-inducer during fertilization in mice. The assay employs silica beads that contain epoxy groups to which purified, mouse oocyte ZP3 is covalently linked (ZP3-beads). ZP3-beads were characterized, e.g. by whole-mount autoradiography and flow cytofluorometry, incubated with capacitated mouse sperm under a variety of conditions, and the extent of sperm binding determined by light microscopy. Results of experiments presented suggest the following: (1) sperm bind specifically to ZP3-beads, but not to silica beads either exposed to 2-aminoethanol or derivatized with oocyte ZP2, fetuin or bovine serum albumin. (2) In nearly all cases, only one sperm binds per ZP3-bead and binding occurs via the sperm head. (3) The extent of sperm binding to ZP3-beads is dependent on ZP3 and sperm concentrations, as well as on incubation time and temperature. (4) Sperm binding to ZP3-beads is unaffected by antibodies directed against ZP3, but is inhibited in a reversible manner by treatment of ZP3-beads with galactose oxidase. (5) Only acrosome-intact sperm bind to ZP3-beads but, once bound, sperm can undergo the acrosome reaction, which results in their release from ZP3-beads. (6) Islet-activating protein and 3-quinuclidinyl benzilate, two inhibitors of the zona pellucida-induced acrosome reaction, prevent sperm bound to ZP3-beads from undergoing the acrosome reaction. These results confirm and extend previous studies of sperm-egg interaction in mice, and suggest that the solid-phase assay will be useful for both cellular and biochemical analyses of mammalian fertilization.


Author(s):  
Mª José Izquierdo-Rico ◽  
Carla Moros-Nicolás ◽  
Míriam Pérez-Crespo ◽  
Ricardo Laguna-Barraza ◽  
Alfonso Gutiérrez-Adán ◽  
...  

Mammalian eggs are surrounded by an extracellular matrix called the zona pellucida (ZP). This envelope participates in processes such as acrosome reaction induction, sperm binding, protection of the oviductal embryo, and may be involved in speciation. In eutherian mammals, this coat is formed of three or four glycoproteins (ZP1–ZP4). While Mus musculus has been used as a model to study the ZP for more than 35 years, surprisingly, it is the only eutherian species in which the ZP is formed of three glycoproteins Zp1, Zp2, and Zp3, Zp4 being a pseudogene. Zp4 was lost in the Mus lineage after it diverged from Rattus, although it is not known when precisely this loss occurred. In this work, the status of Zp4 in several murine rodents was tested by phylogenetic, molecular, and proteomic analyses. Additionally, assays of cross in vitro fertilization between three and four ZP rodents were performed to test the effect of the presence of Zp4 in murine ZP and its possible involvement in reproductive isolation. Our results showed that Zp4 pseudogenization is restricted to the subgenus Mus, which diverged around 6 MYA. Heterologous in vitro fertilization assays demonstrate that a ZP formed of four glycoproteins is not a barrier for the spermatozoa of species with a ZP formed of three glycoproteins. This study identifies the existence of several mouse species with four ZPs that can be considered suitable for use as an experimental animal model to understand the structural and functional roles of the four ZP proteins in other species, including human.


2006 ◽  
Vol 18 (2) ◽  
pp. 254
Author(s):  
H.-H. Rhee ◽  
S.-J. Sa ◽  
H.-T. Cheong ◽  
B.-K. Yang ◽  
C.-K. Park

Plasminogen activators (PAs) are specific proteolytic enzymes that convert the inactive proenzyme plasminogen to plasmin. The plasmin formed is a nonspecific, potent protease that cleaves blood fibrin clots and several other extracellular proteins. The purposes of the present study were (1) to assess the effect of plamin on sperm viability and acrosome reaction (AR), (2) to examine the effect of plasmin on zona pellucida (ZP) solubility and the binding of sperm to ZP, and (3) to evaluate the effect of plasmin on fertilization responses, including penetration and incidence of polyspermy during in vitro fertilization in the pig. Ejaculated semen was collected from three mature Duroc boars by artificial vagina. The same three boars were used for all experiments. The oocyte maturation medium used was North Carolina State University-23 (NCSU-23) medium supplemented with 10% (v/v) porcine follicular fluid (pFF), 0.6 mM cysteine, 10 IU/mL human chorionic gonadotropin (hCG; Sigma-Aldrich Corporation, St. Louis, MO, USA), and 10 IU/mL pregnant mare's serum gonadotropin (PMSG; Sigma). Porcine spermatozoa, which were washed in Dulbecco PBS (Sigma), were resuspended and incubated in fertilization medium (mTBM) containing 0, 0.1, 1.0, 10.0, or 100.0 ng/mL plasmin (Sigma). Data were analyzed by ANOVA and Duncan's multiple-range test using the Statistical Analysis System (SAS Institute, Inc., Cary, NC, USA). The present study suggests that sperm viability was not affected by plasmin treatment. Also, addition of plasmin in doses ranging between 0.1 and 100.0 ng/mL for 2, 4, or 6 h to washed boar spermatozoa resulted in enhancement of acrosome reaction (AR), compared with untreated cells. Concentrations of 0 and 0.1 ng/mL plasmin (83 � 15 and 95 � 18 sperm/oocyte, respectively) had no effect on sperm binding, whereas 1.0 (123 � 21 sperm/oocyte), 10.0 (124 � 16 sperm/oocyte), and 100 ng/mL (124 � 15 sperm/oocyte) plasmin increased (P < 0.05) sperm binding, compared with the control. The zona pellucida solubility (zona digestion time) was significantly (P < 0.05) lower in medium with 1.0 (123 � 24 s), 10.0 (99 � 15 s), or 100.0 ng/mL (95 � 19 s) plasmin, compared with control (176 � 27 s). When porcine oocytes and spermatozoa were co-incubated in various concentrations of plasmin for 6 h, the penetration rate was significantly (P < 0.05) higher in medium with 1.0 ng/mL plasmin (77.5 � 3.1%), compared with control. However, there were no significant differences in the polyspermic rates and mean numbers of sperm (MNS)/oocyte among the groups treated with plasmin and the control group. We found that addition of plasmin to fertilization medium increases the percentage of acrosome-reacted spermatozoa and the sperm-binding ability of the pig ZP. These results suggest that plasmin may play a role in events related to fertilization in the pig.


Author(s):  
C. Barros ◽  
C. Capote ◽  
C. Pérez ◽  
J. Crosby ◽  
M.I. Becker ◽  
...  

Sperm passage through the zona pellucida requires the occurrence of the acrosome reaction. This latter reaction, in turn, is supposedly needed to release the acrosomal enzymes, particularly acrosin which has been involved in the sperm binding to and penetration through the zona pellucida. The application of the immunogold technique using the monoclonal antiacrosin antibody ACR-C2E5 allowed us to identify acrosin in hamster, human and guinea-pig spermatozoa at the optic and scanning electron microscope, in which the immunogold labelling was silver enhanced. At the transmition electron microscope the monoclonal antibody was indirectly labelled with 10nm gold particles. In hamster spermatozoa there were three patterns of labelling: a) either no labelling, or an intense one over acrosomal region of apparently acrosome intact spermatozoa (Figures la,b, 2a & 3a); b) an intense labelling over the inner acrosomal surface and on the acrosomal cap of acrosome reacted spermatozoa (Figures lc,d, 2b & 3b); and c) either a slight labelling over the equatorial region or no labelling on acrosome reacted spermatozoa (Figure le,f,2c).


1985 ◽  
Vol 101 (6) ◽  
pp. 2239-2244 ◽  
Author(s):  
P Primakoff ◽  
H Hyatt ◽  
D G Myles

After the acrosome reaction, the PH-20 surface antigen of guinea pig sperm migrates from its original location on the posterior head surface to a new location on the inner acrosomal membrane (Myles, D.G., and P. Primakoff, 1984, J. Cell Biol., 99:1634-1641). We have isolated three monoclonal antibodies (MAbs) of the IgG1 subclass, PH-20, PH-21, and PH-22, that bind to the PH-20 antigen. The PH-20 MAb strongly inhibited (approximately 90%) sperm binding to the guinea pig egg zona pellucida at saturating antibody concentrations (greater than 20 micrograms/ml). Half-maximal inhibition of sperm binding to the zona was obtained with approximately 2 micrograms/ml PH-20 MAb. The PH-21 MAb at saturating concentration (50 micrograms/ml) partially inhibited (approximately 45%) sperm-zona binding, and the PH-22 MAb (50 micrograms/ml) did not inhibit (0%) sperm-zona binding. Essentially the same amounts of the three MAbs were bound to sperm under the conditions where inhibition (PH-20, PH-21) or no inhibition (PH-22) of sperm-zona binding was observed, which indicates that the different levels of inhibition did not arise from different levels of MAb binding. Competition binding assays with 125I-labeled MAbs showed that PH-21 binding to sperm was not affected by the binding of PH-20 or PH-22. However, that PH-20 and PH-22 blocked each other's binding to sperm suggests that their recognized determinants may be relatively close to one another. The results indicate that the migrating PH-20 antigen has a required function in sperm binding to the zona pellucida and that the PH-20 MAb affects is active site.


1981 ◽  
Vol 34 (2) ◽  
pp. 245 ◽  
Author(s):  
P Quinn ◽  
JD Stanger

In order to obtain consistently a large number of zona-free mouse ova for studies of sperm-egg interactions, a study was made of the relative effectiveness of removing the zona pellucida from ova by mechanical or enzymatic treatments. Ova exposed to pronase before mechanical removal of the zona pellucida in medium devoid of pronase had similar fertilization rates in vitro compared with ova mechanically denuded in the absence of pronase. Ova with pronase-weakened zonae were easier to denude and survived the mechanical manipulations better than the ova denuded by vigorous aspiration in narrow-bore pipettes. However, exposure to pronase did significantly lower the incidence of polyspermy in the naked ova, indicating that some of the enzyme may have diffused across the perivitelline space and damaged sperm-binding sites on the vitelline plasma membrane. The enzyme treatment also reduced the fertilization rate of zona-intact ova.


Reproduction ◽  
2005 ◽  
Vol 129 (3) ◽  
pp. 263-268 ◽  
Author(s):  
Haim Breitbart ◽  
Gili Cohen ◽  
Sara Rubinstein

In order to fertilize, the mammalian spermatozoa should reside in the female reproductive tract for several hours, during which they undergo a series of biochemical modifications collectively called capacitation. Only capacitated sperm can undergo the acrosome reaction after binding to the egg zona pellucida, a process which enables sperm to penetrate into the egg and fertilize it. Polymerization of globular (G)-actin to filamentous (F)-actin occurs during capacitation, depending on protein kinase A activation, protein tyrosine phosphorylation, and phospholipase D activation. F-actin formation is important for the translocation of phospholipase C from the cytosol to the sperm plasma membrane during capacitation. Prior to the occurrence of the acrosome reaction, the F-actin should undergo depolymerization, a necessary process which enables the outer acrosomal membrane and the overlying plasma membrane to come into close proximity and fuse. The binding of the capacitated sperm to the zona pellucida induces a fast increase in sperm intracellular calcium, activation of actin severing proteins which break down the actin fibers, and allows the acrosome reaction to take place.


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