scholarly journals Expression and function of ras proto-oncogene proteins in human sperm cells

1992 ◽  
Vol 102 (3) ◽  
pp. 487-494 ◽  
Author(s):  
R.K. Naz ◽  
K. Ahmad ◽  
P. Kaplan
Keyword(s):  
Sperm Cell ◽  
Acrosome Reaction ◽  
Cell Function ◽  
Beat Frequency ◽  
Human Sperm ◽  
Sperm Cells ◽  
Ras Protein ◽  
Head Displacement ◽  
Sperm Penetration ◽  
And Function

The presence and role of c-ras proteins were investigated in mature human sperm cells. The v-H-ras monoclonal antibody (mAb) against the c-ras protein, p21, reacted specifically with the acrosomal region of methanol-fixed as well as unfixed-live capacitated and non-capacitated human sperm cell in the indirect immunofluorescence technique. The v-H-ras mAb predominantly recognized c-ras protein of 21 kDa on the Western blot of lithium diiodosalicylate (LIS)-solubilized human sperm preparation. The incubation of sperm cells with v-H-ras mAb affected the sperm cell function in the human sperm penetration assay. The antibody significantly reduced the acrosome reaction and release of acrosin activity from the sperm cells. There was no effect of the mAb on percentage motility, although the mAb significantly affected various motility characteristics such as linearity, amplitude of lateral head displacement (ALH) and beat frequency, the motility parameters involved in the hyperactivation phenomenon of sperm cells leading to capacitation and acrosome reaction. These results suggest that the c-ras or c-ras-like proteins are present in mature sperm cell and may have a role in capacitation and/or acrosome reaction of human sperm cell.

scholarly journals EDC IMPACT: Chemical UV filters can affect human sperm function in a progesterone-like manner

2018 ◽  
Vol 7 (1) ◽  
pp. 16-25 ◽  
Author(s):  
A Rehfeld ◽  
D L Egeberg ◽  
K Almstrup ◽  
J H Petersen ◽  
S Dissing ◽  
...  
Keyword(s):  
Acrosome Reaction ◽  
Cell Function ◽  
Human Sperm ◽  
Cumulus Cells ◽  
Viscous Medium ◽  
Sperm Function ◽  
Sperm Cells ◽  
Uv Filters ◽  
Sperm Penetration

Human sperm cell function must be precisely regulated to achieve natural fertilization. Progesterone released by the cumulus cells surrounding the egg induces a Ca2+ influx into human sperm cells via the CatSper Ca2+-channel and thereby controls sperm function. Multiple chemical UV filters have been shown to induce a Ca2+ influx through CatSper, thus mimicking the effect of progesterone on Ca2+ signaling. We hypothesized that these UV filters could also mimic the effect of progesterone on sperm function. We examined 29 UV filters allowed in sunscreens in the US and/or EU for their ability to affect acrosome reaction, penetration, hyperactivation and viability in human sperm cells. We found that, similar to progesterone, the UV filters 4-MBC, 3-BC, Meradimate, Octisalate, BCSA, HMS and OD-PABA induced acrosome reaction and 3-BC increased sperm penetration into a viscous medium. The capacity of the UV filters to induce acrosome reaction and increase sperm penetration was positively associated with the ability of the UV filters to induce a Ca2+ influx. None of the UV filters induced significant changes in the proportion of hyperactivated cells. In conclusion, chemical UV filters that mimic the effect of progesterone on Ca2+ signaling in human sperm cells can similarly mimic the effect of progesterone on acrosome reaction and sperm penetration. Human exposure to these chemical UV filters may impair fertility by interfering with sperm function, e.g. through induction of premature acrosome reaction. Further studies are needed to confirm the results in vivo.

Finasteride interferes with prostaglandin-induced CatSper signalling in human sperm

Reproduction ◽  
2021 ◽  
Vol 161 (5) ◽  
pp. 561-572
Author(s):  
Michala Rosa Birch ◽  
Steen Dissing ◽  
Niels E Skakkebæk ◽  
Anders Rehfeld
Keyword(s):  
Acrosome Reaction ◽  
Endocrine Disrupting Chemicals ◽  
Human Sperm ◽  
Viscous Medium ◽  
Single Cell Imaging ◽  
Multiple Binding Sites ◽  
Transient Rise ◽  
Multiple Binding ◽  
Sperm Penetration ◽  
A Minor

Ca2+ signalling controls human sperm functions necessary for successful fertilization. Multiple endocrine-disrupting chemicals have been found to activate the CatSper Ca2+ channel and thereby interfering with Ca2+ signalling in human sperm. Finasteride is prescribed to men in the fertile age to treat hair loss and its use has been associated with impaired male fertility. Due to the structural relatedness of finasteride to the endogenous CatSper ligand progesterone, this study aimed to investigate whether finasteride affects human sperm in a progestogen-like manner. The effect of finasteride on Ca2+ signalling via CatSper in human sperm was investigated in cell suspensions by single-cell imaging. Additionally, effects on sperm penetration into viscous medium and acrosome reaction were assessed. Finasteride alone caused a minor transient rise in the intracellular, free Ca2+ concentration ([Ca2+]i) at physiologically relevant concentrations. Ca2+ signals induced by PGE1 were inhibited by finasteride displaying mixed type of inhibition consistent with multiple binding sites. Finasteride did not interfere with progesterone-induced Ca2+ signalling and no effect on acrosome reaction or sperm viability was found. Finasteride significantly decreased PGE1-induced penetration into viscous medium but in concentrations above what is measured in blood and seminal fluids during regular finasteride administration. In conclusion, the use of finasteride may affect Ca2+ signalling in human sperm through an interaction with the PGE1-binding site, but to which extend it alters the chances of a successful fertilization needs further investigation. It remains to be investigated whether finasteride administration may give rise to side effects by interfering with prostaglandin signalling elsewhere in the human body.

scholarly journals Localization of phosphatidylserine in boar sperm cell membranes during capacitation and acrosome reaction

Reproduction ◽  
2005 ◽  
Vol 130 (5) ◽  
pp. 615-626 ◽  
Author(s):  
Anke Kurz ◽  
Dagmar Viertel ◽  
Andreas Herrmann ◽  
Karin Müller
Keyword(s):  
Plasma Membrane ◽  
Sperm Cell ◽  
Acrosome Reaction ◽  
Cell Membranes ◽  
Plasma Membranes ◽  
Sperm Cells ◽  
Cytoplasmic Localization ◽  
Lipid Asymmetry ◽  
Viable Cells ◽  
Boar Sperm

One of the essential properties of mammalian, including sperm, plasma membranes is a stable transversal lipid asymmetry with the aminophospholipids, phosphatidylserine (PS) and phosphatidylethanolamine (PE), typically in the inner, cytoplasmic leaflet. The maintenance of this nonrandom lipid distribution is important for the homeostasis of the cell. To clarify the relevance of lipid asymmetry to sperm function, we have studied the localization of PS in boar sperm cell membranes. By using labeled annexin V as a marker for PS and propidium iodide (PI) as a stain for nonviable cells in conjunction with different methods (flow cytometry, fluorescence and electron microscopy), we have assessed the surface exposure of PS in viable cells during sperm genesis, that is, before and during capacitation as well as after acrosome reaction. An approach was set up to address also the presence of PS in the outer acrosome membrane. The results show that PS is localized in the cytoplasmic leaflet of the plasma membrane as well as on the outer acrosome membrane. Our results further indicate the cytoplasmic localization of PS in the postacrosomal region. During capacitation and acrosome reaction of spermatozoa, PS does not become exposed on the outer surface of the viable cells. Only in a subpopulation of PI-positive sperm cells does PS became accessible upon capacitation. The stable cytoplasmic localization of PS in the plasma membrane, as well as in the outer acrosome membrane, is assumed to be essential for a proper genesis of sperm cells during capacitation and acrosome reaction.

scholarly journals Expression and putative function of fibronectin and its receptor (integrin α5β1) in male and female gametes during bovine fertilization in vitro

Reproduction ◽  
2009 ◽  
Vol 138 (3) ◽  
pp. 471-482 ◽  
Author(s):  
Mirjan Thys ◽  
Hans Nauwynck ◽  
Dominiek Maes ◽  
Maarten Hoogewijs ◽  
Dries Vercauteren ◽  
...  
Keyword(s):  
Sperm Cell ◽  
Acrosome Reaction ◽  
Male Gamete ◽  
Inhibitory Effect ◽  
Fertilization In Vitro ◽  
Integrin Receptor ◽  
Male And Female ◽  
Sperm Penetration ◽  
Bovine Spermatozoa

Fibronectin (Fn) is a 440 kDa glycoprotein assumed to participate in sperm–egg interaction in human. Recently, it has been demonstrated that Fn – when present during bovine IVF – strongly inhibits sperm penetration. The present study was conducted firstly to evaluate the expression of Fn and its integrin receptor (α5β1) on male and female bovine gametes using indirect immunofluorescence and secondly, to determine the function of Fn during bovine IVF. Endogenous Fn was detected underneath the zona pellucida (ZP) and integrin α5 on the oolemma of cumulus-denuded oocytes. Bovine spermatozoa displayed integrin α5 at their equatorial segment after acrosome reaction. We established that the main inhibitory effect of exogenously supplemented Fn was located at the sperm–oolemma binding, with a (concurrent) effect on fusion, and this can probably be attributed to the binding of Fn to spermatozoa at the equatorial segment, as shown by means of Alexa Fluor 488-conjugated Fn. Combining these results, the inhibitory effect of exogenously supplemented Fn seemed to be exerted on the male gamete by binding to the exposed integrin α5β1 receptor after acrosome reaction. The presence of endogenous Fn underneath the ZP together with integrin α5 expression on oolemma and acrosome-reacted (AR) sperm cell surface suggests a ‘velcro’ interaction between the endogenous Fn ligand and corresponding receptors on both (AR) sperm cell and oolemma, initiating sperm–egg binding.

scholarly journals Choline dehydrogenase polymorphism rs12676 is a functional variation associated with changes in human sperm cell function

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Amy Rose Johnson ◽  
Sai Lao ◽  
Tongwen Wang ◽  
Joseph Galanko ◽  
Steven Zeisel
Keyword(s):  
Sperm Cell ◽  
Cell Function ◽  
Human Sperm ◽  
Functional Variation ◽  
Choline Dehydrogenase

scholarly journals High-resolution 4-D acquisition of freely swimming human sperm cells without staining

2020 ◽  
Vol 6 (15) ◽  
pp. eaay7619 ◽  
Author(s):  
Gili Dardikman-Yoffe ◽  
Simcha K. Mirsky ◽  
Itay Barnea ◽  
Natan T. Shaked
Keyword(s):  
Refractive Index ◽  
High Resolution ◽  
Sperm Cell ◽  
High Speed ◽  
Three Dimensional ◽  
Human Sperm ◽  
Refractive Index Profile ◽  
Sperm Cells ◽  
Biological Assays ◽  
Natural Movement

We present a new acquisition method that enables high-resolution, fine-detail full reconstruction of the three-dimensional movement and structure of individual human sperm cells swimming freely. We achieve both retrieval of the three-dimensional refractive-index profile of the sperm head, revealing its fine internal organelles and time-varying orientation, and the detailed four-dimensional localization of the thin, highly-dynamic flagellum of the sperm cell. Live human sperm cells were acquired during free swim using a high-speed off-axis holographic system that does not require any moving elements or cell staining. The reconstruction is based solely on the natural movement of the sperm cell and a novel set of algorithms, enabling the detailed four-dimensional recovery. Using this refractive-index imaging approach, we believe that we have detected an area in the cell that is attributed to the centriole. This method has great potential for both biological assays and clinical use of intact sperm cells.

Sperm require beta-N-acetylglucosaminidase to penetrate through the egg zona pellucida

Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1279-1289 ◽  
Author(s):  
D.J. Miller ◽  
X. Gong ◽  
B.D. Shur
Keyword(s):  
Zona Pellucida ◽  
Acrosome Reaction ◽  
Competitive Inhibitor ◽  
Dependent Manner ◽  
Surface Receptors ◽  
Acrosomal Exocytosis ◽  
Sperm Penetration ◽  
Glycosidase Inhibitor ◽  
Beta Glucosidase ◽  
And Function

Fertilization in the mouse is initiated by sperm beta 1,4-galactosyltransferase (GalTase) binding to terminal N-acetylglucosamine residues on the zona pellucida glycoprotein ZP3. Binding of ZP3 induces exocytosis of the sperm acrosome, whose contents are believed to digest a penetration slit in the zona matrix through which sperm reach the egg. As a consequence of acrosomal exocytosis, GalTase is redistributed to the lateral aspect of the sperm head, where its function remains unknown. In this location, GalTase could conceivably impede zona penetration by binding to N-acetylglucosamine residues exposed on zona pellucida glycoproteins. Therefore, in this study we investigated the presence and function of acrosomal glycosidases capable of removing the GalTase-binding site from zona pellucida glycoproteins. beta-N-acetylglucosaminidase was found at very high levels in sperm, being more than 20-fold higher than other glycosidases assayed. The specific isozymic variant was identified as beta-hexosaminidase B. beta-N-acetylglucosaminidase was localized to sperm acrosomes by biochemical and indirect immunofluorescence studies and was released during the acrosome reaction, as expected for an enzyme involved in zona penetration. To determine if, in fact, acrosomal beta-N-acetylglucosaminidase facilitated penetration through the zona, an assay was developed using eggs that were rendered incapable of triggering the block to polyspermy. A specific competitive inhibitor of beta-N-acetylglucosaminidase activity, PUGNAC, inhibited sperm penetration of the zona in a dose-dependent manner, whereas a closely related beta-glucosidase inhibitor, PUGLU, had no effect on zona penetration or on beta-N-acetylglucosaminidase activity. Neither glycosidase inhibitor affected sperm motility or induction of the acrosome reaction. These results demonstrate that beta-N-acetylglucosaminidase is found in sperm acrosomes and is released during the acrosome reaction, at which time it facilitates sperm penetration through the zona. These results also imply that sperm have developed mechanisms to prevent the formation of stable interactions between surface receptors and their zona pellucida ligands during penetration.

Artificially selected human sperm morphology after swim-up processing

2012 ◽  
Vol 90 (10) ◽  
pp. 1207-1214 ◽  
Author(s):  
Tomislav Vladić ◽  
Erik Petersson
Keyword(s):  
Sperm Cell ◽  
Sperm Morphology ◽  
Meta Analysis ◽  
Sperm Concentration ◽  
Human Sperm ◽  
Sperm Cells ◽  
Before And After ◽  
Cell Components ◽  
Sperm Midpiece ◽  
Assisted Fertilization

The swim-up technique is a clinical practice used to select highly motile sperm cells from patient ejaculates to use in assisted fertilization. The aim of this study was to investigate whether the length of different sperm-cell components is related to gamete function. Thus, we explored whether swim-up technique selects for longer sperm cells than mean sperm cells from unprocessed ejaculates. Sperm midpiece, tail endpiece, and total length were measured before and after the swim-up selection by means of contrast-phase and electron microscopy. Correlations between sperm dimensions, sperm motility, and sperm concentration were also investigated. Swim-up selected cells with longer midpiece compared with the unprocessed fractions (5.8 μm (CI 5.52–6.16 μm) vs. 5.3 μm (CI 4.97–5.61 μm), p < 0.05) and shorter tail endpiece (7.8 μm (CI 7.11–8.44 μm) vs. 8.5 μm (CI 7.81–9.14 μm), p < 0.05 after meta-analysis), whereas no effect of swim-up selection was detected on the total sperm cell length. Individuals producing high sperm concentrations had longer sperm midpiece than had men producing lower sperm concentrations. It is concluded that short sperm flagellar tips with long midpieces may be used as biomarkers in infertility therapy.

scholarly journals HPV Infection Affects Human Sperm Functionality by Inhibition of Aquaporin-8

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1241
Author(s):  
Giorgia Pellavio ◽  
Federica Todaro ◽  
Paola Alberizzi ◽  
Claudia Scotti ◽  
Giulia Gastaldi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Model Simulation ◽  
Cell Volume Regulation ◽  
Human Sperm ◽  
Hpv Infection ◽  
Sperm Cells ◽  
Confocal Immunofluorescence ◽  
End Stage ◽  
And Function ◽  
L1 Protein

Human sperm cells express different aquaporins (AQPs), AQP3, 7, 8, 11, which are localized both in the plasma membrane and in intracellular structures. Besides cell volume regulation and end stage of cytoplasm removal during sperm maturation, the role of AQPs extends also to reactive oxygen species (ROS) elimination. Moreover, oxidative stress has been shown to inhibit AQP-mediated H2O2 permeability. A decrease in AQPs functionality is related to a decrease in sperm cells number and motility. Here we investigate the possible effect of human Papillomavirus (HPV) on both expression and function of AQPs in human sperm cells of patients undergoing infertility couple evaluation. Stopped-flow light-scattering experiments demonstrated that HPV infection heavily reduced water permeability of sperm cells in normospermic samples. Confocal immunofluorescence experiments showed a colocalization of HPV L1 protein with AQP8 (Pearson’s correlation coefficient of 0.61), confirmed by co-immunoprecipitation experiments. No interaction of HPV with AQP3 and AQP7 was observed. A 3D model simulation of L1 protein and AQP8 interaction was also performed. Present findings may suggest that HPV infection directly inhibits AQP8 functionality and probably makes sperm cells more sensitive to oxidative stress.

Sperm-mediated gene transfer: effect on bovine in vitro embryo production

Zygote ◽  
2012 ◽  
Vol 21 (4) ◽  
pp. 325-329 ◽  
Author(s):  
Renata Simões ◽  
Alessandra Corallo Nicacio ◽  
Mario Binelli ◽  
Fabiola Freitas de Paula-Lopes ◽  
Marcella Pecora Milazzotto ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Sperm Cell ◽  
Dna Delivery ◽  
Cell Interaction ◽  
Control Group ◽  
Exogenous Dna ◽  
Incubation Periods ◽  
Sperm Penetration ◽  
And Function

SummaryThe technique of sperm-mediated gene transfer (SMGT) can be used to delivery exogenous DNA into the oocyte. However, it has low repeatability and produces inconsistent results. In order to optimize this technique, it is necessary to study the mechanism by which DNA enters the sperm cell and integrates in the sperm genome. Furthermore, studies must focus in the maintenance of sperm cell viability and function. The aim of this study was to evaluate different SMGT protocols of sperm electroporation or capacitation (CaI) aiming to maintain sperm viability in the production of bovine embryos in vitro. Frozen–thawed semen was divided in two experimental groups (electroporation or CaI) and one control group (non-treated cells). For the electroporation method, five different voltages (100, 500, 750, 1000 or 1500 V) with 25 μF capacitance were used. For CaI treatment, combinations of two CaI concentrations (250 nM or 500 nM), two incubation periods of sperm cells with CaI (1 or 5 min) and two incubation periods that mimicked time of sperm cell interaction with exogenous DNA molecules (1 or 2 h) were evaluated. According to our data, electroporation and CaI treatments do not prevent sperm penetration and oocyte fertilization and can be an alternative method to achieve satisfactory DNA delivery in SMGT protocols.

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