Evidence that acrosin activity is important for the development of fusibility of mammalian spermatozoa with the oolemma: inhibitor studies using the golden hamster

Zygote ◽  
1993 ◽  
Vol 1 (1) ◽  
pp. 79-91 ◽  
Author(s):  
Hiroko Takano ◽  
R. Yanagimachi ◽  
Umbert A. Urch
Keyword(s):  
Plasma Membrane ◽  
Acrosome Reaction ◽  
Free Medium ◽  
Inhibitory Effects ◽  
Chloromethyl Ketone ◽  
Gamete Fusion ◽  
Sperm Plasma Membrane ◽  
Acrosomal Enzyme ◽  
Acrosin Activity ◽  
Mammalian Spermatozoa

SummaryThe sperm plasma membrane over the equatorial segment of the acrosome gains the ability to fuse with the oolemma some time during, or after, the acrosome reaction. Since acrosin is a major component of the acrosome matrix that dissolves during the acrosome reaction, we sought to determine the effect of acrosin inhibitors on the sperm's ability to fuse with the oolemma. Five acrosin inhibitors (soybean trypsin inhibitor (SBTI), leupeptin, benzamidine, N-p-tosyl-1-lysin-chloromethyl ketone (TLCK) and phenylmethylsulphonyl fluoride (PMSF) and one non-acrosin inhibitor (N-p-tosyl-1-phenylalanine chloromethyl ketone (TPCK) were tested at non-toxic levels (below motility-disturbing concentrations). These inhibitors were added at three different times: (1) during the acrosome reaction of spermatozoa, (2) during sperm-oocyte contact and fusion, and (3) soon after sperm-oocyte fusion was completed. TLCK prevented sperm-oocyte fusion by inhibiting the acrosome reaction.PMSF inhibited gamete fusion, without inhibiting the acrosome reaction. SBTI, leupeptin and benzamidine also inhibited gamete fusion, but they had no effect if spermatozoa were allowed to acrosome-react in inhibitor-free medium. TPCK was without any inhibitory effects, suggesting that chymotrypsin-like enzymes are not involved in gamete fusion. Although acrosin inhibitors prevented acrosome-reacted spermatozoa from becoming fusion-competent, acrosin (and trypsin) alone could not make the plasma membrane of acrosome-intact spermatozoa fusion-competent. The data suggest that (1) the plasma membrane of the acrosomal region first undergoes dramatic changes immediately before or during the acrosome reaction and (2) acrosin released from the acrosome during the acrosome reaction further alters biophysical and biochemical characteristics of the plasma membrane over the equatorial segment. Such dual changes make the plasma membrane of this specialised region of the spermatozoon competent to fuse with the oolemma. Acrosin may not be the only acrosomal enzyme to participate in these changes.

scholarly journals Effect of calmodulin on the stimulation of capacitation and acrosome reaction of frozen thawed bull spermatozoa

2017 ◽  
Vol 45 (3) ◽  
pp. 1-9
Author(s):  
QS Akter ◽  
KMA Tareq ◽  
K Hamano ◽  
RB Gilchrist
Keyword(s):  
Acrosome Reaction ◽  
Specific Binding ◽  
Staining Technique ◽  
Inhibitory Effect ◽  
Free Medium ◽  
Inhibitory Effects ◽  
Specific Binding Protein ◽  
Bovine Spermatozoa ◽  
Mammalian Spermatozoa

Capacitation and acrosome reaction (AR) are the prerequisites for successful fertilization by mammalian spermatozoa. Intracellular calcium (Ca2+) has a regulatory role in sperm motility, capacitation, and AR. Calmodulin (CaM) antagonists calmidazolium (CZ) and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W7) were used to investigate the possible role of CaM, a Ca2+ specific binding protein, on motility, capacitation and AR of frozen-thawed bovine spermatozoa. Capacitation and AR in sperm were evaluated by using chlortetracycline (CTC) staining technique. Addition of the 1 mM dibutyryl cAMP (dbcAMP) and 100 ?M 1-methy l-3-isobutylxanthine (IBMX) to CaM antagonists treated sperm incubated in the presence of NaHCO3 and CaCl2 in media overcome the inhibitory effects of these antagonists to support capacitation and AR at 4 h of incubation period. In contrast, addition of dbcAMP with IBMX induced AR in spermatozoa incubated with NaHCO3-free medium but these compounds did not induce AR in cells incubated in CaCl2-free medium. However, the addition of dbcAMP and IBMX partially, but significantly (p<0.01) reversed the inhibitory effect of W7 and CZ on the sperm capacitation and AR. These results suggest that CaM may play an important role in the regulation of capacitation and AR in frozen-thawed bovine spermatozoa.Bang. J. Anim. Sci. 2016. 45 (3): 1-9

scholarly journals Sperm Lipid Markers of Male Fertility in Mammals

2021 ◽  
Vol 22 (16) ◽  
pp. 8767
Author(s):  
Shuwen Shan ◽  
Fangzheng Xu ◽  
Marc Hirschfeld ◽  
Bertram Brenig
Keyword(s):  
Plasma Membrane ◽  
Lipid Metabolism ◽  
Male Fertility ◽  
Acrosome Reaction ◽  
Membrane Lipids ◽  
Reproductive Function ◽  
Cellular Processes ◽  
Male Reproductive Function ◽  
Sperm Plasma Membrane ◽  
Mammalian Spermatozoa

Sperm plasma membrane lipids are essential for the function and integrity of mammalian spermatozoa. Various lipid types are involved in each key step within the fertilization process in their own yet coordinated way. The balance between lipid metabolism is tightly regulated to ensure physiological cellular processes, especially referring to crucial steps such as sperm motility, capacitation, acrosome reaction or fusion. At the same time, it has been shown that male reproductive function depends on the homeostasis of sperm lipids. Here, we review the effects of phospholipid, neutral lipid and glycolipid homeostasis on sperm fertilization function and male fertility in mammals.

Mechanism of human sperm activation by extracellular ATP

1996 ◽  
Vol 270 (6) ◽  
pp. C1709-C1714 ◽  
Author(s):  
C. Foresta ◽  
M. Rossato ◽  
P. Chiozzi ◽  
F. Di Virgilio
Keyword(s):  
Plasma Membrane ◽  
Acrosome Reaction ◽  
Human Sperm ◽  
Extracellular Atp ◽  
Effective Concentration ◽  
Na Channel ◽  
Monovalent Cations ◽  
Sperm Activation ◽  
Gated Channel ◽  
Sperm Plasma Membrane

We have identified the mechanism whereby extracellular ATP (ATPe) triggers the acrosome reaction in human spermatozoa. This nucleotide opens a ligand-gated ion channel expressed on the sperm plasma membrane. ATPe threshold and 50% effective concentration calculated on the total added ATPe are 0.1 and 2 mM, respectively, corresponding to a free ATP concentration (ATP4-) of 3 and 200 microM, respectively. The ATPe-gated channel is selective for monovalent cations (Na+, choline, and methylglucamine), whereas on the contrary, permeability to Ca2+ is negligible. Isosmolar replacement of extracellular Na+ with sucrose fully blocked ATPe-dependent sperm activation, thus suggesting a mandatory role for Na+ influx. These results show that human sperm express an ATPe-gated Na+ channel that might have an important role in sperm activation before egg fertilization.

Interactions between gametes leading to fertilization: the sperm's eye view

1995 ◽  
Vol 7 (4) ◽  
pp. 927 ◽  
Author(s):  
BT Storey
Keyword(s):  
Plasma Membrane ◽  
Acrosome Reaction ◽  
Mammalian Species ◽  
Sperm Chromatin ◽  
Peptide Backbone ◽  
Mouse Sperm ◽  
Gamete Interactions ◽  
Sperm Plasma Membrane ◽  
Sperm Penetration ◽  
Strong Candidate

Sexual reproduction requires that the gamete carrying the male-derived haploid chromatin join with the gamete carrying the female-derived haploid chromatin during fertilization to produce the diploid zygote. To accomplish this feat, the sperm must not only meet the egg, it must recognize the egg and be recognized in turn by the egg, and in the end must enter and be engulfed by the egg. In this selective overview of gamete interactions that lead to fertilization, encounters of three kinds, followed by the finale of gamete fusion, are considered from the sperm's viewpoint, with particular emphasis on the mammalian species with the mouse as the principal model. The first encounter is with the zona pellucida of the egg, to whose surface the sperm must bind. Mouse sperm appear to have four binding sites for zona ligands. Three interact with sugar moieties of the oligosaccharide chains of the mouse zona glycoprotein ZP3; the fourth binds a peptide backbone arginine. Capacitation is not required for this encounter, but is obligate for the second encounter--induction of the acrosome reaction in the bound sperm. The acrosome reaction is an exocytotic process that makes available the enzymatic machinery needed for sperm penetration the zona which is the end point of a sequence of reactions directed by intracellular signalling systems. In mouse sperm, these systems are presumed to be activated by ligands on ZP3 binding to ligand-specific sperm receptors with consequent aggregation of receptors. No receptor has been identified with certainty, nor have candidates for putative ZP3 ligands been identified. Completion of the acrosome reaction allows the sperm to penetrate the zona and, bind to the egg plasma membrane, thereby completing the third encounter. In the mouse, a 94-kDa protein appears essential for this binding. In the guinea-pig, a sperm plasma membrane protein (formerly PH-30, now fertilin), is a strong candidate for the mediator of the fusion process by which the egg engulfs the sperm. Decondensation of the sperm chromatin reverses the remarkable packing of DNA organized by sperm protamines. Mitochondrial DNA is also engulfed by the egg; the question of whether this DNA makes a small finite, or null, contribution to cytosolic inheritance is still in debate. The puzzles attending these encounters are presented as reminders of the intricacy and fascination, as well as of the vital necessity, of gamete interaction.

Progesterone interaction with sperm plasma membrane, calcium influx and induction of the acrosome reaction

1999 ◽  
Vol 7 (2) ◽  
pp. 81-93 ◽  
Author(s):  
Christopher Bray ◽  
Jackson CK Brown ◽  
Steve Publicover ◽  
Christopher LR Barratt
Keyword(s):  
Plasma Membrane ◽  
Steroid Hormones ◽  
Nuclear Receptors ◽  
Acrosome Reaction ◽  
Calcium Influx ◽  
Membrane Receptors ◽  
Sperm Plasma Membrane ◽  
The Subject ◽  
Genomic Effects ◽  
Intense Research

In contrast to the classic action of steroid hormones through cytoplasmic/nuclear receptors, there is an accumulating body of data which strongly suggests that they have a direct effect on cells mediated through putative membrane receptors, a so-called non-genomic action. Although such non-genomic effects were discovered 50 years ago it is only in the last 15 years that the subject has become an area of intense research.

scholarly journals Ion fluxes through the progesterone-activated channel of the sperm plasma membrane

1993 ◽  
Vol 294 (1) ◽  
pp. 279-283 ◽  
Author(s):  
C Foresta ◽  
M Rossato ◽  
F Di Virgilio
Keyword(s):  
Plasma Membrane ◽  
Pertussis Toxin ◽  
Acrosome Reaction ◽  
Monovalent Cations ◽  
Voltage Gated ◽  
Free Choline ◽  
Sperm Plasma Membrane ◽  
Ionic Changes ◽  
Voltage Gated Channels ◽  
Fast Acting

We have characterized ionic changes triggered by progesterone in human spermatozoa. This steroid, which is a fast-acting stimulator of the acrosome reaction, triggered a rapid increase in the cytoplasmic Ca2+ concentration ([Ca2+]i) which was entirely due to influx across the plasma membrane, as it was obliterated by chelation of extracellular Ca2+. Ca2+ fluxes were insensitive to verapamil and pertussis toxin, thus suggesting that they did not occur via voltage-gated channels and did not involve a pertussis toxin-sensitive G protein, and were potentiated in Na(+)-free, choline-containing or methylglucamine-containing medium. Progesterone also caused a depolarization of the plasma membrane in Na(+)-containing as well as in choline- or methyl-glucamine-containing saline; depolarization was larger in the absence of extracellular Ca2+, suggesting that Na+ and Ca2+ fluxes occurred through the same channel. Progesterone was able to trigger the acrosome reaction in the three media investigated (Na+, choline and methylglucamine), provided that extracellular Ca2+ was also present. We conclude that progesterone activates a membrane ion channel that is permeable to monovalent cations as well as to Ca2+.

Ultrastructural mapping of a sperm plasma membrane autoantigen before and after the acrosome reaction

1988 ◽  
Vol 19 (4) ◽  
pp. 387-399 ◽  
Author(s):  
Nair Esaguy ◽  
Jeffrey E. Welch ◽  
Michael G. O'Rand
Keyword(s):  
Plasma Membrane ◽  
Acrosome Reaction ◽  
Before And After ◽  
Sperm Plasma Membrane

scholarly journals Ca2+ channels from the sea urchin sperm plasma membrane.

1990 ◽  
Vol 95 (2) ◽  
pp. 273-296 ◽  
Author(s):  
A Liévano ◽  
E C Vega-SaenzdeMiera ◽  
A Darszon
Keyword(s):  
Plasma Membrane ◽  
Sea Urchin ◽  
Acrosome Reaction ◽  
Main Channel ◽  
Open Probability ◽  
Boltzmann Function ◽  
Sperm Plasma Membrane ◽  
Egg Jelly ◽  
Sea Urchin Sperm ◽  
Ca2 Channels

Ca2+ influx across the sea urchin sperm plasma membrane is a necessary step during the egg jelly-induced acrosome reaction. There is pharmacological evidence for the involvement of Ca2+ channels in this influx, but their presence has not been directly demonstrated because of the small size of this cell. Sea urchin sperm Ca2+ channels are being studied by fusing isolated plasma membranes into planar lipid bilayers. With this strategy, a Ca2+ channel has been detected with the following characteristics: (a) the channel exhibits a high mainstate conductance (gamma MS) of 172 pS in 50 mM CaCl2 solutions with voltage-dependent decaying to smaller conductance states at negative Em; (b) the channel is blocked by millimolar concentrations of Cd2+, Co2+, and La3+, which also inhibit the egg jelly-induced acrosome reaction; (c) the gamma MS conductance sequence for the tested divalent cations is the following: Ba2+ greater than Sr2+ greater than Ca2+; and (d) the channel discriminates poorly for divalent over monovalent cations (PCa/PNa = 5.9). The sperm Ca2+ channel gamma MS rectifies in symmetrical 10 mM CaCl2, having a maximal slope conductance value of 94 pS at +100 mV applied to the cis side of the bilayer. Under these conditions, a different single-channel activity of lesser conductance became apparent above the gamma MS current at positive membrane potentials. Also in 10 mM Ca2+ solutions, Mg2+ permeates through the main channel when added to the cis side with a PCa/PMg = 2.9, while it blocks when added to the trans side. In 50 mM Ca2+ solutions, the gamma MS open probability has values of 1.0 at voltages more positive than -40 mV and decreases at more negatives potentials, following a Boltzmann function with an E0.5 = -72 mV and an apparent gating charge value of 3.9. These results describe a novel Ca2(+)-selective channel, and suggest that the main channel works as a single multipore assembly.

scholarly journals Activation of sperm in the female reproductive tract in mammals

2020 ◽  
Vol 76 (09) ◽  
pp. 6445-2020
Author(s):  
ALEKSANDRA KRAWCZYK ◽  
JADWIGA JAWORSKA-ADAMU
Keyword(s):  
Plasma Membrane ◽  
Acrosome Reaction ◽  
Reproductive Tract ◽  
Female Reproductive Tract ◽  
Perivitelline Space ◽  
Male Gametes ◽  
Activation Mechanisms ◽  
Sperm Plasma Membrane ◽  
Controlled Reproduction ◽  
Two Stages

The formation of a new diploidal organism is preceded by a series of mutual interactions of haploidal gametes. This process is very complicated and requires the prior activation of reproductive cells. Male gametes eventually mature in the female reproductive tract, acquiring mobility and fertilization. This process takes place in two stages. Sperms are first capacitated. This phenomenon is reversible and leads to structural, cytophysiological and biochemical changes in the sperm plasma membrane as well as to the sperm hyperactivation. Then, due to the contact with the zona pellucida of the oocyte, the irreversible acrosome reaction occurs. This process involves the fusion of the sperm plasma membrane with the outer membrane of the acrosome, the release of enzymes and exposure of the inner acrosome membrane. This enables sperm to penetrate towards the perivitelline space and oolemma. Contact with the oocyte initiates a series of interactions leading to egg activation and the fusion of gametes. Each of these stages involves many different factors that result in the recognition, attraction and adhesion of reproductive cells. Knowledge about the activation mechanisms can improve the effectiveness of supported and controlled reproduction techniques.

scholarly journals Evidence for involvement of metalloendoproteases in a step in sea urchin gamete fusion.

1988 ◽  
Vol 107 (2) ◽  
pp. 539-544 ◽  
Author(s):  
J L Roe ◽  
H A Farach ◽  
W J Strittmatter ◽  
W J Lennarz
Keyword(s):  
Plasma Membrane ◽  
Membrane Fusion ◽  
Sea Urchin ◽  
Acrosome Reaction ◽  
Fusion Process ◽  
Cortical Granule ◽  
Cortical Granules ◽  
Gamete Fusion ◽  
Cortical Granule Exocytosis ◽  
Cytoplasmic Continuity

Membrane fusion events are required in three steps in sea urchin fertilization: the acrosome reaction in sperm, fusion of the plasma membrane of acrosome-reacted sperm with the plasma membrane of the egg, and exocytosis of the contents of the egg cortical granules. We recently reported the involvement of a Zn2+-dependent metalloendoprotease in the acrosome reaction (Farach, H. C., D. I. Mundy, W. J. Strittmatter, and W. J. Lennarz. 1987. J. Biol. Chem. 262:5483-5487). In the current study, we investigated the possible involvement of metalloendoproteases in the two other fusion events of fertilization. The use of inhibitors of metalloendoproteases provided evidence that at least one of the fusion events subsequent to the acrosome reaction requires such enzymes. These inhibitors did not block the binding of sperm to egg or the process of cortical granule exocytosis. However, sperm-egg fusion, assayed by the ability of the bound sperm to establish cytoplasmic continuity with the egg, was inhibited by metalloendoprotease substrate. Thus, in addition to the acrosome reaction, an event in the gamete fusion process requires a metalloendoprotease.

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