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Asian Journal of Andrology Sep 2008To investigate the in vitro effects of insulin and leptin on human sperm motility, viability, acrosome reaction and nitric oxide (NO) production.
AIM
To investigate the in vitro effects of insulin and leptin on human sperm motility, viability, acrosome reaction and nitric oxide (NO) production.
METHODS
Washed human spermatozoa from normozoospermic donors were treated with insulin (10 microIU) and leptin (10 nmol). Insulin and leptin effects were blocked by inhibition of their intracellular effector, phosphotidylinositol 3-kinase (PI3K), by wortmannin (10 micromol) 30 min prior to insulin and leptin being given. Computer-assisted semen analysis was used to assess motility after 1, 2 and 3 h of incubation. Viability was assessed by fluorescence-activated cell sorting using propidium iodide as a fluorescent probe. Acrosome-reacted cells were observed under a fluorescent microscope using fluorescein-isothiocyanate-Pisum sativum agglutinin as a probe. NO was measured after treating the sperm with 4,5-diaminofluorescein-2/diacetate (DAF-2/DA) and analyzed by fluorescence-activated cell sorting.
RESULTS
Insulin and leptin significantly increased total motility, progressive motility and acrosome reaction, as well as NO production.
CONCLUSION
This study showed the in vitro beneficial effects of insulin and leptin on human sperm function. These hormones could play a role in enhancing the fertilization capacity of human spermatozoa.
Topics: Acrosome Reaction; Cell Survival; Flow Cytometry; Humans; Hypoglycemic Agents; In Vitro Techniques; Insulin; Leptin; Male; Nitric Oxide; Sperm Motility; Spermatozoa
PubMed: 18645684
DOI: 10.1111/j.1745-7262.2008.00421.x -
Developmental Biology Dec 2014Extracellular zinc regulates cell proliferation via the MAP1 kinase pathway in several cell types, and has been shown to act as a signaling molecule. The testis contains...
Extracellular zinc regulates cell proliferation via the MAP1 kinase pathway in several cell types, and has been shown to act as a signaling molecule. The testis contains a relatively high concentration of Zn(2+), required in both the early and late stages of spermatogenesis. Despite the clinical significance of this ion, its role in mature sperm cells is poorly understood. In this study, we characterized the role of Zn(2+) in sperm capacitation and in the acrosome reaction. Western blot analysis revealed the presence of ZnR of the GPR39 type in sperm cells. We previously demonstrated the presence of active epidermal growth factor receptor (EGFR) in sperm, its possible transactivation by direct activation of G-protein coupled receptor (GPCR), and its involvement in sperm capacitation and in the acrosome reaction (AR). We show here that Zn(2+) activates the EGFR during sperm capacitation, which is mediated by activation of trans-membrane adenylyl cyclase (tmAC), protein kinase A (PKA), and the tyrosine kinase, Src. Moreover, the addition of Zn(2+) to capacitated sperm caused further stimulation of EGFR and phosphatydil-inositol-3-kinase (PI3K) phosphorylation, leading to the AR. The stimulation of the AR by Zn(2+) also occurred in the absence of Ca(2+) in the incubation medium, and required the tmAC, indicating that Zn(2+) activates a GPCR. The AR stimulated by Zn(2+) is mediated by GPR39 receptor, PKA, Src and the EGFR, as well as the EGFR down-stream effectors PI3K, phospholipase C (PLC) and protein kinase C (PKC). These data support a role for extracellular zinc, acting through the ZnR, in regulating multiple signaling pathways in sperm capacitation and the acrosome reaction.
Topics: Acrosome Reaction; Adenylyl Cyclases; Animals; Blotting, Western; Cattle; Cyclic AMP-Dependent Protein Kinases; ErbB Receptors; Immunohistochemistry; Male; Receptors, G-Protein-Coupled; Signal Transduction; Sperm Capacitation; Zinc; src-Family Kinases
PubMed: 25446533
DOI: 10.1016/j.ydbio.2014.10.009 -
Journal of Andrology 2002Identification of norepinephrine (NE) within the microenvironment of the bovine oviduct suggests a potential role for catecholamines in the events surrounding...
Identification of norepinephrine (NE) within the microenvironment of the bovine oviduct suggests a potential role for catecholamines in the events surrounding fertilization. Previous studies have shown that the catecholamines capacitate and induce the acrosome reaction in spermatozoa from several species. The current project was undertaken to investigate the role of catecholamines in bovine sperm capacitation and the acrosome reaction. Freshly ejaculated bovine spermatozoa were incubated in NE (0-1000 ng/mL) and induced to acrosome-react with lysophosphatidylcholine (LPC). Additionally, spermatozoa capacitated with heparin were incubated with NE (0-1000 ng/mL) to assess its ability to induce the acrosome-reaction in capacitated spermatozoa. Concentrations of NE were chosen on the basis of physiological concentrations previously determined for bovine oviductal fluid. NE at concentrations of 10 and 20 ng/mL capacitated bovine spermatozoa after 2 hours of incubation. Additionally, spermatozoa incubated for 2 hours with heparin were induced to acrosome-react with 10 and 20 ng/mL NE. Interestingly, higher concentrations of NE inhibited both capacitation and the acrosome reaction. Incubating spermatozoa with dopamine or epinephrine did not result in capacitation or the acrosome reaction, suggesting that the action of NE was specific to that catecholamine. The ability of NE to capacitate or induce the acrosome reaction appears to be dependent on the presence of another membrane-destabilizing factor. Although adrenergic receptors have not been identified on spermatozoa from any species, the action of NE on spermatozoa may be a receptor-mediated event. This study suggests a possible function for oviductal catecholamines in sperm preparation prior to fertilization.
Topics: Acrosome Reaction; Animals; Cattle; Dopamine; Epinephrine; In Vitro Techniques; Male; Norepinephrine; Sperm Capacitation; Spermatozoa; Sympathomimetics
PubMed: 12002437
DOI: No ID Found -
Molecular Human Reproduction Aug 2011Upon ejaculation, mammalian spermatozoa have to undergo a sequence of physiological transformations within the female reproductive tract that will allow them to reach... (Review)
Review
Upon ejaculation, mammalian spermatozoa have to undergo a sequence of physiological transformations within the female reproductive tract that will allow them to reach and fertilize the egg. These include initiation of motility, hyperactivation of motility and perhaps chemotaxis toward the egg, and culminate in the acrosome reaction that permits sperm to penetrate the protective vestments of the egg. These physiological responses are triggered through the activation of sperm ion channels that cause elevations of sperm intracellular pH and Ca(2+) in response to certain cues within the female reproductive tract. Despite their key role in sperm physiology and their absolute requirement for the process of fertilization, sperm ion channels remain poorly understood due to the extreme difficulty in application of the patch-clamp technique to spermatozoa. This review covers the topic of sperm ion channels in the following order: first, we discuss how the intracellular Ca(2+) and pH signaling mediated by sperm ion channels controls sperm behavior during the process of fertilization. Then, we briefly cover the history of the methodology to study sperm ion channels, which culminated in the recent development of a reproducible whole-cell patch-clamp technique for mouse and human cells. We further discuss the main approaches used to patch-clamp mature mouse and human spermatozoa. Finally, we focus on the newly discovered sperm ion channels CatSper, KSper (Slo3) and HSper (H(v)1), identified by the sperm patch-clamp technique. We conclude that the patch-clamp technique has markedly improved and shifted our understanding of the sperm ion channels, in addition to revealing significant species-specific differences in these channels. This method is critical for identification of the molecular mechanisms that control sperm behavior within the female reproductive tract and make fertilization possible.
Topics: Acrosome Reaction; Animals; Calcium; Calcium Channels; Chemotaxis; Female; Fertilization; Humans; Hydrogen-Ion Concentration; Ion Channel Gating; Ion Channels; Large-Conductance Calcium-Activated Potassium Channels; Male; Mice; Patch-Clamp Techniques; Signal Transduction; Sperm Motility; Sperm-Ovum Interactions; Spermatozoa
PubMed: 21642646
DOI: 10.1093/molehr/gar044 -
Cells May 2024As in most cells, intracellular pH regulation is fundamental for sperm physiology. Key sperm functions like swimming, maturation, and a unique exocytotic process, the... (Review)
Review
As in most cells, intracellular pH regulation is fundamental for sperm physiology. Key sperm functions like swimming, maturation, and a unique exocytotic process, the acrosome reaction, necessary for gamete fusion, are deeply influenced by pH. Sperm pH regulation, both intracellularly and within organelles such as the acrosome, requires a coordinated interplay of various transporters and channels, ensuring that this cell is primed for fertilization. Consistent with the pivotal importance of pH regulation in mammalian sperm physiology, several of its unique transporters are dependent on cytosolic pH. Examples include the Ca channel CatSper and the K channel Slo3. The absence of these channels leads to male infertility. This review outlines the main transport elements involved in pH regulation, including cytosolic and acrosomal pH, that participate in these complex functions. We present a glimpse of how these transporters are regulated and how distinct sets of them are orchestrated to allow sperm to fertilize the egg. Much research is needed to begin to envision the complete set of players and the choreography of how cytosolic and organellar pH are regulated in each sperm function.
Topics: Male; Hydrogen-Ion Concentration; Animals; Cytosol; Humans; Acrosome; Spermatozoa; Mammals; Acrosome Reaction
PubMed: 38786087
DOI: 10.3390/cells13100865 -
Scientific Reports Oct 2015All cells are covered by glycans, an individually unique layer of oligo- and polysaccharides that are critical moderators of self-recognition and other cellular-level...
All cells are covered by glycans, an individually unique layer of oligo- and polysaccharides that are critical moderators of self-recognition and other cellular-level interactions (e.g. fertilization). The functional similarity between these processes suggests that gamete surface glycans may also have an important, but currently overlooked, role in sexual selection. Here we develop a user-friendly methodological approach designed to facilitate future tests of this possibility. Our proposed method is based on flow cytometric quantification of female-induced sperm acrosome reaction and sperm surface glycan modifications in the Mediterranean mussel Mytilus galloprovincialis. In this species, as with many other taxa, eggs release water-soluble factors that attract conspecific sperm (chemoattraction) and promote potentially measurable changes in sperm behavior and physiology. We demonstrate that flow cytometry is able to identify sperm from other seawater particles as well as accurately measure both acrosome reaction and structural modifications in sperm glycans. This methodological approach can increase our understanding of chemically-moderated gamete-level interactions and individual-specific gamete recognition in Mytilus sp. and other taxa with similar, easily identifiable acrosome structure. Our approach is also likely to be applicable to several other species, since carbohydrate-mediated cellular-level interactions between gametes are universal among externally and internally fertilizing species.
Topics: Acrosome; Acrosome Reaction; Animals; Bivalvia; Female; Fertilization; Flow Cytometry; Lectins; Male; Monosaccharides; Polysaccharides; Spermatozoa
PubMed: 26470849
DOI: 10.1038/srep15321 -
Scientific Reports Sep 2018Mammalian sperm are unable to fertilize the egg immediately after ejaculation. To gain fertilization competence, they need to undergo a series of modifications inside...
Mammalian sperm are unable to fertilize the egg immediately after ejaculation. To gain fertilization competence, they need to undergo a series of modifications inside the female reproductive tract, known as capacitation. Capacitation involves several molecular events such as phosphorylation cascades, hyperpolarization of the plasma membrane and intracellular Ca changes, which prepare the sperm to develop two essential features for fertilization competence: hyperactivation and acrosome reaction. Since sperm cells lack new protein biosynthesis, post-translational modification of existing proteins plays a crucial role to obtain full functionality. Here, we show the presence of acetylated proteins in murine sperm, which increase during capacitation. Pharmacological hyperacetylation of lysine residues in non-capacitated sperm induces activation of PKA, hyperpolarization of the sperm plasma membrane, CatSper opening and Ca influx, all capacitation-associated molecular events. Furthermore, hyperacetylation of non-capacitated sperm promotes hyperactivation and prepares the sperm to undergo acrosome reaction. Together, these results indicate that acetylation could be involved in the acquisition of fertilization competence of mammalian sperm.
Topics: Acetylation; Acrosome Reaction; Animals; Lysine; Male; Mice; Sperm Capacitation; Spermatozoa
PubMed: 30190490
DOI: 10.1038/s41598-018-31557-5 -
Protein & Cell Feb 2011Fertilization is a process involving multiple steps that lead to the final fusion of one sperm and the oocyte to form the zygote. One of the steps, acrosome reaction... (Review)
Review
Fertilization is a process involving multiple steps that lead to the final fusion of one sperm and the oocyte to form the zygote. One of the steps, acrosome reaction (AR), is an exocytosis process, during which the outer acrosome membrane fuses with the inner sperm membrane, leading to the release of acrosome enzymes that facilitate sperm penetration of the egg investments. Though AR has been investigated for decades, the initial steps of AR in vivo, however, remain largely unknown. A well elucidated model holds the view that AR occurs on the surface of the zona pellucida (ZP), which is triggered by binding of sperm with one of the ZP glycosylated protein, ZP3. However, this model fails to explain the large number of 'falsely' acrosome-reacted sperms found within the cumulus layer in many species examined. With the emerging evidence of cross-talk between sperm and cumulus cells, the potential significance of AR in the cumulus oophorus, the outer layer of the egg, has been gradually revealed. Here we review the acrosome status within the cumulus layer, the cross-talk between sperm and cumulus cells with the involvement of a novel sperm-released factor, NYD-SP8, and re-evaluate the importance and physiological significance of the AR in the cumulus in fertilization.
Topics: Acrosome Reaction; Cell Communication; Cumulus Cells; Female; Fertilization; Humans; Male; Membrane Proteins; Oocytes; Progesterone; Spermatozoa
PubMed: 21380641
DOI: 10.1007/s13238-011-1022-5 -
Andrology Mar 2014Zona pellucida-based induction of acrosome reaction (AR) is a popular and well-accepted hypothesis. However, this hypothesis is being challenged in recent years and it...
Zona pellucida-based induction of acrosome reaction (AR) is a popular and well-accepted hypothesis. However, this hypothesis is being challenged in recent years and it has been proposed that the cumulus cells might be the site of AR. In our previous study, we reported the presence of a synaptic protein Liprin α3 on sperm acrosome, and proposed its role in AR. This study was designed to understand the role of Liprin α3 and its interacting proteins in regulation of AR. It is observed that the presence of anti-Liprin α3 antibody inhibits the process of AR. Colocalization experiments demonstrate the coexistence of leucocyte antigen related (LAR) protein, Rab-interacting molecule (RIM) and Liprin α3 on sperm acrosome thereby completing the identification of all the members of RIM/MUNC/Rab3A/liprinα complex required for membrane fusion. This study demonstrates the effect of LAR ligands such as Syndecans, Nidogens and LAR wedge domain peptide on AR. We could see an increase in AR in presence of these ligands. On the basis of these data, we speculate that in presence of ligands or wedge peptide, LAR undergoes dimerization leading to inhibition of phosphatase activity and increase in AR. The presence of one of the ligands Syndecan-1 on cumulus cells led us to hypothesize that it is Syndecan which induces AR in vivo and thus another site of AR could lie in cumulus.
Topics: Acrosome; Acrosome Reaction; Animals; Antibodies; Cumulus Cells; Dimerization; Humans; Ligands; Male; Membrane Glycoproteins; Mice; Rats; Receptor-Like Protein Tyrosine Phosphatases, Class 2; Spermatozoa; Syndecans; Vesicular Transport Proteins
PubMed: 24327330
DOI: 10.1111/j.2047-2927.2013.00167 -
The International Journal of... 2019The acrosome reaction is induced in the sperm of Cynops pyrrhogaster immediately in response to a ligand protein called acrosome reaction-inducing substance (ARIS) in...
The acrosome reaction is induced in the sperm of Cynops pyrrhogaster immediately in response to a ligand protein called acrosome reaction-inducing substance (ARIS) in the egg jelly at fertilization, whereas a spontaneous acrosome reaction occurs time-dependently in correlation with the decline of sperm quality for fertilization. The ARIS-induced acrosome reaction was recently found to be mediated by TRPV4 in association with the NMDA type glutamate receptor, although the intracellular mediators for the acrosome reaction are largely unclear. In the present study, spontaneous acrosome reaction was significantly inhibited by Ni, RN1734, and diltiazem, which blocks Cav3.2, TRPV4 or TRPM8, and the cyclic nucleotide-gated channel, respectively. In contrast, expression of Ca-activated transmembrane and soluble adenylyl cyclases was detected in the sperm of C. pyrrhogaster by reverse transcription-polymerase chain reaction. Activator of transmembrane or soluble adenylyl cyclases (forskolin or HCO ) independently promoted spontaneous acrosome reaction, while an inhibitor of each enzyme (MD12330A or KH7) inhibited it only in the sperm with high potential for spontaneous acrosome reaction. An inhibitor of protein kinase A (H89) inhibited spontaneous acrosome reaction in a manner independent of sperm potential for spontaneous acrosome reaction. Surprisingly, KH7 significantly inhibited ARIS-induced acrosome reaction, but its effect was seen in a small percentage of sperm. H89 had no effect on ARIS-induced acrosome reaction. These results suggest that C. pyrrhogaster sperm possess multiple intracellular pathways for acrosome reaction, involving Ca permeable channels, adenylyl cyclases and PKA, and that two pathways having distinct dependencies on adenylyl cyclases may contribute to ARIS-induced acrosome reaction at fertilization.
Topics: Acrosome Reaction; Adenylyl Cyclases; Animals; Diltiazem; Female; Fertilization; Gene Expression Regulation, Enzymologic; Ion Channels; Male; Nickel; Ovum; Salamandridae; Signal Transduction; Sperm-Ovum Interactions; Spermatozoa; Sulfonamides
PubMed: 32149368
DOI: 10.1387/ijdb.190092aw