scholarly journals The slower the better: how sperm capacitation and acrosome reaction is modified in the presence of estrogens

Reproduction ◽  
2012 ◽  
Vol 143 (3) ◽  
pp. 297-307 ◽  
Author(s):  
Natasa Sebkova ◽  
Martina Cerna ◽  
Lukas Ded ◽  
Jana Peknicova ◽  
Katerina Dvorakova-Hortova
Keyword(s):  
Acrosome Reaction ◽  
Estrogen Receptor Beta ◽  
Calcium Ionophore ◽  
Membrane Receptors ◽  
Sperm Capacitation ◽  
Mouse Sperm ◽  
Synthetic Estrogens ◽  
Dependent Protein ◽  
Plasma Membrane Receptors

In order for mammalian sperm to obtain a fertilizing ability, they must undergo a complex of molecular changes, called capacitation. During capacitation, steroidal compounds can exert a fast nongenomic response in sperm through their interaction with plasma membrane receptors, and activate crucial signaling pathways leading to time-dependent protein tyrosine phosphorylation (TyrP). Estrogen receptor beta was detected in epididymal mouse sperm; therefore, the effect of 17B-estradiol, estrone, estriol, and 17A-ethynylestradiol on mouse sperm capacitation in vitro was investigated. The effect was evaluated by positive TyrP in sperm heads and in the whole sperm lysates. Simultaneously, the state of the acrosome after the calcium ionophore-induced acrosome reaction was assessed. Generally, estrogens displayed a time and concentration-dependent stimulatory effect on sperm TyrP during capacitation. In contrast, the number of sperm that underwent the acrosome reaction was lower in the experimental groups. It has been demonstrated that both natural and synthetic estrogens can modify the physiological progress of mouse sperm capacitation. The potential risk in the procapacitation effect of estrogens can also be seen in the decreased ability of sperm to undergo the acrosome reaction. In conclusion, the capacitating ability of sperm can be significantly lowered by increasing the level of estrogens in the environment.

Sperm from beta 1,4-galactosyltransferase-null mice are refractory to ZP3-induced acrosome reactions and penetrate the zona pellucida poorly

Development ◽  
1997 ◽  
Vol 124 (20) ◽  
pp. 4121-4131 ◽  
Author(s):  
Q. Lu ◽  
B.D. Shur
Keyword(s):  
Acrosome Reaction ◽  
Direct Evidence ◽  
Calcium Ionophore ◽  
Wild Type ◽  
Sperm Surface ◽  
Gamete Recognition ◽  
Dependent Signal ◽  
Relative Inability ◽  
Egg Coat

A variety of sperm surface components have been suggested to mediate gamete recognition by binding to glycoside ligands on the egg coat glycoprotein ZP3. The function of each of these candidate receptors is based upon varying degrees of circumstantial and direct evidence; however, the effects on fertilization of targeted mutations in any of these candidate receptors have not yet been reported. In this paper, we describe the effects of targeted mutations in beta1,4-galactosyltransferase, the best studied of the candidate receptors for ZP3. Surprisingly, galactosyltransferase-null (gt[−/−]) males are fertile; however, sperm from gt(−/−) males bind less radiolabeled ZP3 than wild-type sperm, and are unable to undergo the acrosome reaction in response to either ZP3 or anti-galactosyltransferase antibodies, as do wild-type sperm. In contrast, gt(−/−) sperm undergo the acrosome reaction normally in response to calcium ionophore, which bypasses the requirement for ZP3 binding. The inability of gt(−/−) sperm to undergo a ZP3-induced acrosome reaction renders them physiologically inferior to wild-type sperm, as assayed by their relative inability to penetrate the egg coat and fertilize the oocyte in vitro. Thus, although ZP3 binding and subsequent induction of the acrosome reaction are dispensable for fertilization, they impart a physiological advantage to the fertilizing sperm. A second strain of mice was created that is characterized by a loss of of the long galactosyltransferase isoform responsible for ZP3-dependent signal transduction, but which maintains normal levels of Golgi galactosylation. Sperm from these mice show that the defective sperm-egg interactions in gt(−/−) mice are due directly to a loss of the long galactosyltransferase isoform from the sperm surface and are independent of the state of intracellular galactosylation during spermatogenesis.

322 EFFECT OF SODIUM NITROPRUSSIDE ON BUFFALO SPERM CAPACITATION IN VITRO

2007 ◽  
Vol 19 (1) ◽  
pp. 276 ◽  
Author(s):  
L. Boccia ◽  
L. Attanasio ◽  
A. De Rosa ◽  
G. Pellerano ◽  
R. Di Palo ◽  
...  
Keyword(s):  
Sodium Nitroprusside ◽  
Acrosome Reaction ◽  
Production Efficiency ◽  
Control Group ◽  
Sperm Capacitation ◽  
Promoting Effect ◽  
Vitro Fertilization ◽  
Domestic Species ◽  
Frozen Semen

The overall in vitro embryo production efficiency in buffalo is hampered by the poor fertilization rate. It is known that the quality of the frozen semen may affect fertilization efficiency. However, it is not possible to rule out that the process of capacitation, required by spermatozoa to acquire the fertilizing ability, is impaired in the in vitro fertilization (IVF) system. Although several agents have been proven to induce sperm capacitation in vitro, heparin treatment is still the most efficient method in most of the domestic species. There is evidence that capacitation is part of an oxidative process and that nitric oxide (NO) acts as a capacitation inducer in human (Herrero et al. 1999 Biol. Reprod. 61, 575–581) and bovine (Rodriguez et al. 2005 Anim. Reprod. Sci. 85, 231–242) spermatozoa. The aim of the present study was to evaluate whether sodium nitroprusside (SNP), a well-known generator of NO in vitro, improves buffalo sperm capacitation in vitro. Frozen–thawed sperm from a bull previously tested for IVF were treated by swim-up in order to select only the motile population. Spermatozoa were incubated in the presence of 0.01 mM heparin (control group) for 1 h (n = 266), 2 h (n = 270), and 3 h (n = 306), and in the presence of 10 �M SNP for 1 h (n = 302), 2 h (n = 286), and 3 h (n = 260). The concentration of SNP was chosen on the basis of a preliminary dose-response trial (0.1 �M, 1 �M, and 10 �M). Following incubation with these agents, sperm were exposed for 15 min to 60 �g mL-1 of lysophosphatidylcholine, an agent known to induce acrosome reaction only on capacitated spermatozoa. Trypan blue was used first to differentiate live from dead spermatozoa and the dried smears were then fixed in 37% formaldehyde and stained with Giemsa for acrosome evaluation by microscopic examination. The proportion of acrosome-reacted spermatozoa in each group was used to assess the efficiency of capacitation under different incubation conditions. Differences between groups were analyzed by chi-squared test. No dead spermatozoa were found in all groups. Following 1-h sperm treatment with either heparin or SNP, the proportion of acrosome-reacted spermatozoa was similar (35.3% vs. 28.5%, respectively). However, extending the incubation time to 2 h, SNP significantly (P < 0.01) increased the incidence of acrosome reaction compared to heparin (60.1% vs. 44.1%, respectively). Analogously, when the sperm treatment was prolonged to 3 h, SNP gave a significantly (P < 0.01) higher percentage of acrosome reaction compared to the control (68.8% vs. 36.6%, respectively). In conclusion, sperm treatment with SNP for either 2 or 3 h significant improved the efficiency of buffalo sperm capacitation in vitro compared with heparin, that is, the capacitating agent currently used in the IVF system. The promoting effect of SNP indirectly indicates that NO acts as a capacitation inducer in buffalo spermatozoa. Finally, these results suggest the need to evaluate the effect of SNP on the fertilizing capability of buffalo spermatozoa in vitro.

Effect of estrogens on sperm capacitation and acrosome reaction in vitro

2009 ◽  
Vol 81 (2) ◽  
pp. 155
Author(s):  
L. Ded ◽  
A. Dorosh ◽  
P. Dostalova ◽  
J. Peknicova
Keyword(s):  
Acrosome Reaction ◽  
Sperm Capacitation

In vitro induction of the acrosome reaction in ovine spermatozoa by calcium ionophore A23187

2003 ◽  
Vol 51 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Ö. Uçar ◽  
T. J. Parkinson
Keyword(s):  
Phase Contrast ◽  
Acrosome Reaction ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Contrast Microscopy ◽  
The Relationship ◽  
In Vitro Induction ◽  
Artificial Vagina

The relationship between concentration of calcium ionophore A23187 and incubation time upon the proportion of spermatozoa undergoing acrosome reaction (AR) in vitro was investigated in rams from a commercial artificial insemination (AI) program. Two ejaculates were collected by artificial vagina from each of nine rams of three breeds (Finn Dorset, Charolais and Suffolk) aged 8-36months. Each ejaculate was diluted in a skimmed milk extender. Spermatozoa were thereafter incubated for 45 or 60min in modified Tyrode's medium (TALP) which contained either zero, 0.1 or 1.0µM/l A23187. After fixing in 10% formaldehyde, the number of spermatozoa that had undergone AR was determined by phase contrast microscopy. In pre-incubation samples, 21.3± 3.3% of spermatozoa had undergone AR. Percentages of acrosome reacted spermatozoa were significantly (P<0.001) increased after incubation with A23187. After incubation with 0.1µM/l A23187 for 45 and 60min there were 22.4±3.0% and 31.7±4.3% acrosome reacted spermatozoa, respectively. After incubation with 1.0µM/l A23187 for 45 and 60min there were 46.2±6.5% and 53.8±5.9% acrosome reacted spermatozoa, whilst corresponding numbers in control samples were 17.0±2.7% and 22.3±4.2%. There was also a significant (P<0.001) effect of individual animals upon the responses to different concentrations of A23187. These findings indicate that (i) A23187 can be used to assess the AR of ovine spermatozoa in vitro and (ii) there are effects of individual animals upon the proportion of spermatozoa undergoing AR.

scholarly journals Human neuroblastoma cells acquire regulated secretory properties and different sensitivity to Ca2+ and alpha-latrotoxin after exposure to differentiating agents.

1989 ◽  
Vol 108 (6) ◽  
pp. 2291-2300 ◽  
Author(s):  
E Sher ◽  
S Denis-Donini ◽  
A Zanini ◽  
C Bisiani ◽  
F Clementi
Keyword(s):  
Electron Microscopy ◽  
De Novo ◽  
Neuroblastoma Cells ◽  
Calcium Ionophore ◽  
Membrane Receptors ◽  
Human Neuroblastoma Cells ◽  
Human Neuroblastoma ◽  
Adequate Model ◽  
Human Neurons

IMR-32 human neuroblastoma cells are unable to release [3H]dopamine in response to secretagogues. However, they express a normal complement of membrane receptors and ion channels which are efficiently coupled to second messenger production. In the present study we took advantage of the ability of this cell line to differentiate in vitro in the presence of either dibutyrryl-cAMP or 5-bromodeoxyuridine, to analyze any developmentally regulated changes in its secretory properties. Uptake, storage, and release of [3H]dopamine were studied biochemically and by autoradiography. The calcium ionophore ionomycin, phorbol 12-myristate 13-acetate and the presynaptic acting neurotoxin alpha-latrotoxin were used in both control and differentiated cells as secretagogue agents. The presence of secretory organelles was investigated by electron microscopy; the expression of secretory organelle markers, such as chromogranin/secretogranin proteins (secretory proteins) and synaptophysin (membrane protein), was detected by Western blotting and immunofluorescence. The results obtained indicate that IMR-32 cells acquire regulated secretory properties after in vitro drug-induced differentiation: (a) they assemble "de novo" secretory organelles, as revealed by electron microscopy and detection of secretory organelle markers, and (b) they are able to store [3H]dopamine and to release the neurotransmitter in response to secretagogue stimuli. Furthermore, secretagogue sensitivity was found to be different, depending on the differentiating agent. In fact, dibutyrryl-cAMP treated cells release [3H]dopamine in response to alpha-latrotoxin, but not in response to ionomycin, whereas 5-bromodeoxyuridine treated cells release the neurotransmitter in response to both secretagogues. All together these results suggest that IMR-32 cells represent an adequate model for studying the development of the secretory apparatus in cultured human neurons.

scholarly journals Progress of sperm IZUMO1 relocation during spontaneous acrosome reaction

Reproduction ◽  
2014 ◽  
Vol 147 (2) ◽  
pp. 231-240 ◽  
Author(s):  
Natasa Sebkova ◽  
Lukas Ded ◽  
Katerina Vesela ◽  
Katerina Dvorakova-Hortova
Keyword(s):  
Fusion Protein ◽  
Acrosome Reaction ◽  
Mating Behaviour ◽  
Calcium Ionophore ◽  
Cumulus Cells ◽  
Sperm Head ◽  
High Rate ◽  
Field Mice ◽  
Species Specific

It has been recently shown in mice that sperm undergo acrosome reaction (AR) by passing through cumulus cells; furthermore, the acrosome-reacted sperm can bind to zona pellucida and consequently fertilise the egg. During AR, the relocation of the primary fusion protein IZUMO1 into the equatorial segment is crucial for sperm–egg fusion. There is a high rate of spontaneous AR in rodents, with up to 60% in promiscuous species. The aim of this study was to clarify whether the IZUMO1 relocation in sperm after spontaneous and induced AR is the same, and whether there is a correlation between the speed of IZUMO1 relocation and species-specific mating behaviour in field mice. Immunofluorescent detection of IZUMO1 dynamics during the in vitro capacitation, spontaneous, calcium ionophore and progesterone-induced AR was monitored. Our results show that during spontaneous AR, there is a clear IZUMO1 relocation from the acrosomal cap to the equatorial segment, and further over the whole sperm head. In addition, there is positive tail tyrosine phosphorylation (TyrP) associated with hyperactive motility. Moreover, the beginning and the progress of IZUMO1 relocation and tail TyrP positively correlate with the level of promiscuity and the acrosome instability in promiscuous species. The findings that crucial molecular changes essential for sperm–egg fusion represented by dynamic movements of IZUMO1 also happen during spontaneous AR are vital for understanding fertilisation in mice.

scholarly journals Matrine Inhibits Mouse Sperm Function by Reducing Sperm [Ca2+]i and Phospho-ERK1/2

2015 ◽  
Vol 35 (1) ◽  
pp. 374-385 ◽  
Author(s):  
Tao Luo ◽  
Qian-xing Zou ◽  
Yuan-qiao He ◽  
Hua-feng Wang ◽  
Na Li ◽  
...  
Keyword(s):  
Acrosome Reaction ◽  
Male Reproduction ◽  
In Vitro Toxicity ◽  
Sperm Function ◽  
Ionophore A23187 ◽  
Epididymal Sperm ◽  
Mouse Sperm ◽  
Extracellular Signal ◽  
Mature Mouse

Background: Matrine is a bioactive alkaloid that has a variety of pharmacological effects and is widely used in Chinese medicine. However, its effects on male reproduction are not well known. In this study, we aimed to investigate the in vitro toxicity of matrine on mature mouse sperm. Methods: Mouse cauda epididymal sperm were exposed to matrine (10-200 µM) in vitro. The viability, motility, capacitation, acrosome reaction and fertilization ability of the mouse sperm were examined. Furthermore, the intracellular calcium concentration ([Ca2+]i), calcium (Catsper) and potassium (Ksper) currents, and phosphorylation of extracellular signal regulated kinases 1/2 (p-ERK1/2) of the sperm were analyzed. Results: After exposure to 100 µM or more of matrine, mouse cauda epididymal sperm exhibited a significant reduction in total motility, progressive motility, linear velocity and acrosome reaction rate induced by Ca2+ ionophore A23187. As a result, the fertilization ability of mouse sperm was remarkably decreased by matrine. Our data further demonstrated that matrine significantly reduced sperm [Ca2+]i and [Ca2+]i-related p-ERK1/2; however, both the CatSper and KSper currents, which are thought to interactively regulate Ca2+ influx in sperm, were not affected by matrine. Conclusion: Our findings indicate that matrine inhibits mouse sperm function by reducing sperm [Ca2+]i and suppressing the phosphorylation of ERK1/2.

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