scholarly journals Why doesn’t conventional IVF work in the horse? The equine oviduct as a microenvironment for capacitation/fertilization

Reproduction ◽  
2016 ◽  
Vol 152 (6) ◽  
pp. R233-R245 ◽  
Author(s):  
Bart Leemans ◽  
Bart M Gadella ◽  
Tom A E Stout ◽  
Catharina De Schauwer ◽  
Hilde Nelis ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Secretory Granules ◽  
Lectin Binding ◽  
Mammalian Species ◽  
Protein Tyrosine Phosphorylation ◽  
Limited Information ◽  
Acid Base Balance ◽  
Protein Tyrosine

In contrast to man and many other mammalian species, conventionalin vitrofertilization (IVF) with horse gametes is not reliably successful. The apparent inability of stallion spermatozoa to penetrate the zona pellucidain vitrois most likely due to incomplete activation of spermatozoa (capacitation) because of inadequate capacitating or fertilizing media.In vivo, the oviduct and its secretions provide a microenvironment that does reliably support and regulate interaction between the gametes. This review focuses on equine sperm–oviduct interaction. Equine sperm–oviduct binding appears to be more complex than the presumed species-specific calcium-dependent lectin binding phenomenon; unfortunately, the nature of the interaction is not understood. Various capacitation-related events are induced to regulate sperm release from the oviduct epithelium and most data suggest that exposure to oviduct secretions triggers sperm capacitationin vivo. However, only limited information is available about equine oviduct secreted factors, and few have been identified. Another aspect of equine oviduct physiology relevant to capacitation is acid–base balance.In vitro, it has been demonstrated that stallion spermatozoa show tail-associated protein tyrosine phosphorylation after binding to oviduct epithelial cells containing alkaline secretory granules. In response to alkaline follicular fluid preparations (pH 7.9), stallion spermatozoa also show tail-associated protein tyrosine phosphorylation, hyperactivated motility and (limited) release from oviduct epithelial binding. However, these ‘capacitating conditions’ are not able to induce the acrosome reaction and fertilization. In conclusion, developing a defined capacitating medium to support successful equine IVF will depend on identifying as yet uncharacterized capacitation triggers present in the oviduct.

scholarly journals Intracellular calcium and protein tyrosine phosphorylation during the release of bovine sperm adhering to the fallopian tube epithelium in vitro

Reproduction ◽  
2005 ◽  
Vol 129 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Roberto Gualtieri ◽  
Raffaele Boni ◽  
Elisabetta Tosti ◽  
Maria Zagami ◽  
Riccardo Talevi
Keyword(s):  
Tyrosine Phosphorylation ◽  
Ionophore A23187 ◽  
Protein Tyrosine Phosphorylation ◽  
Protein Tyrosine ◽  
Phosphorylated Proteins ◽  
Bovine Sperm ◽  
Surface Remodeling ◽  
Bovine Species

In mammals, sperm adhesion to the epithelial cells lining the oviductal isthmus plays a key role in the maintenance of motility and in the selection of superior quality subpopulations. In the bovine species, heparin and other sulfated glycoconjugates powerfully induce the synchronous release of sperm adhering to tubal epithelium in vitro and may represent the signal which triggers release at ovulation in vivo. Sperm detachment may be due either to surface remodeling or to hyperactivation brought about by capacitation. In this paper, the dynamics of intracellular free Ca2+concentration ([Ca2+]i) and protein tyrosine phosphorylation in sperm during and after heparin-induced release from in vitro cultured oviductal monolayers were assessed to determine whether this event is due to capacitation. Moreover, Ca2+-ionophore A23187, thapsigargin, thimerosal and caffeine were used to determine whether [Ca2+]i increase and/or hyperactivation can induce sperm release. Results showed that: 1. heparin-released sperm have significantly higher [Ca2+]i than adhering sperm; 2. heparin induces a [Ca2+]i elevation in the sperm head followed by detachment from the monolayers; 3. external Ca2+is not required for heparin-induced release; 4. [Ca2+]i increase and/or hyperactivation are unable to release sperm; and 5. heparin-released sperm have an increased level of tyrosine phosphorylated proteins compared with adhering sperm. In conclusion, although heparin is considered a long-lasting capacitation agent, it quickly modulates the capacitation of bovine sperm adhering to the fallopian epithelium, probably leading to surface remodeling and therefore to the release of sperm selected and stored within the oviduct through adhesion.

scholarly journals Signal transduction mechanisms involved in in vitro ram sperm capacitation

Reproduction ◽  
2006 ◽  
Vol 132 (5) ◽  
pp. 721-732 ◽  
Author(s):  
Patricia Grasa ◽  
José Álvaro Cebrián-Pérez ◽  
Teresa Muiño-Blanco
Keyword(s):  
Tyrosine Phosphorylation ◽  
Calcium Influx ◽  
Calcium Entry ◽  
Calcium Entry Blocker ◽  
Protein Tyrosine Phosphorylation ◽  
Sperm Capacitation ◽  
Protein Tyrosine ◽  
Entry Blocker ◽  
Ram Sperm

We validate the chlortetracycline (CTC) technique for the evaluation of capacitation and acrosome reaction-like changes in ram sperm, carrying out a double estimation of the acrosome status after treatment with lysophosphatidylcholine, using fluorescein isocyanate (FITC)-RCA/ethidium homodimer 1 (EthD-1) and CTC/EthD-1. Highly consistent results and a positive correlation between the results of acrosome-reacted sperm evaluated with both techniques were obtained. In this study, we evaluate the effects of ram sperm capacitation of BSA, Ca2+, NaHCO3and cAMP agonists and their influence on the associated protein tyrosine phosphorylation. We found a time-dependent increase in capacitation related to protein tyrosine phosphorylation, either in the absence or the presence of BSA. The addition of an increasing concentration of cholesterol to samples containing BSA did not influence results. The effect of bicarbonate was concentration-dependent, with a significantly lowered value of non-capacitated sperm in the presence 18 and 25 mM. The addition of extracellular calcium did not significantly increase either the proportion of capacitated sperm or the protein tyrosine phosphorylation signalling, although a significantly higher value of acrosome-reacted sperm was found in samples containing 4 mM Ca2+. cAMP agonists increased capacitated sperm and protein tyrosine phosphorylation signalling. The inhibition of protein kinase A by H-89 caused a decrease in sperm capacitation. Addition of a calcium-entry blocker (Verapamil; Sigma) did not influence results, which suggests that the calcium entry blocker was unable to inhibit the calcium influx associated with capacitation in ram sperm. Our findings might benefit our understanding of the biochemical mechanisms involved in mammalian sperm capacitation and ultimately, fertility.

Capacitation of mouse spermatozoa. I. Correlation between the capacitation state and protein tyrosine phosphorylation

Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 1129-1137 ◽  
Author(s):  
P.E. Visconti ◽  
J.L. Bailey ◽  
G.D. Moore ◽  
D. Pan ◽  
P. Olds-Clarke ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Tyrosine Phosphorylation ◽  
Bovine Serum ◽  
Female Reproductive Tract ◽  
Dependent Manner ◽  
Protein Tyrosine Phosphorylation ◽  
Sperm Capacitation ◽  
Protein Tyrosine

The molecular basis of mammalian sperm capacitation, defined functionally as those processes that confer on the sperm the acquisition of fertilization-competence either in vivo in the female reproductive tract or in vitro, is poorly understood. We demonstrate here that capacitation of caudal epididymal mouse sperm in vitro is accompanied by a time-dependent increase in the protein tyrosine phosphorylation of a subset of proteins of M(r) 40,000-120,000. Incubation of sperm in media devoid of bovine serum albumin, CaCl2 or NaHCO3, components which individually are required for capacitation, prevent the sperm from undergoing capacitation as assessed by the ability of the cells to acquire the pattern B chlortetracycline fluorescence, to undergo the zona pellucida-induced acrosome reaction and, in some cases, to fertilize metaphase II-arrested eggs in vitro. In each of these cases the protein tyrosine phosphorylation of the subset of capacitation-associated proteins does not occur. Protein tyrosine phosphorylation of these particular proteins, as well as sperm capacitation, can be recovered in media devoid of each of these three constituents (bovine serum albumin, CaCl2 or NaHCO3) by adding back the appropriate component in a concentration-dependent manner. The requirement of NaHCO3 for these phosphorylations is not due to an alkalinization of intracellular sperm pH or to an increase in media pH. Caput epididymal sperm, which lack the ability to undergo capacitation in vitro, do not display this capacitation-dependent subset of tyrosine phosphorylated proteins in complete media even after extended incubation periods, and do not fertilize metaphase II-arrested eggs in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Protein tyrosine phosphorylation mediates TNF-induced endothelial-neutrophil adhesion in vitro

1998 ◽  
Vol 274 (2) ◽  
pp. H513-H519 ◽  
Author(s):  
Susan A. Kelly ◽  
Pascal J. Goldschmidt-Clermont ◽  
Emily E. Milliken ◽  
Toshiyuki Arai ◽  
Elise H. Smith ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Adhesion Molecules ◽  
Neutrophil Adhesion ◽  
Protein Tyrosine Phosphorylation ◽  
Protein Tyrosine ◽  
Tnf Α ◽  
Dose Dependent

Proinflammatory cytokines initiate the vascular inflammatory response via the upregulation of adhesion molecules on the luminal endothelial surface. We investigated directly the role of protein tyrosine phosphorylation in the upregulation of the endothelial adhesion molecules, intercellular adhesion molecule 1 (ICAM-1) and E-selectin, and the consequent adhesion of neutrophils, after tumor necrosis factor (TNF)-α-stimulation of human aortic endothelial cells in vitro. Time- and dose-dependent TNF-α-stimulated ICAM-1 and E-selectin upregulation and neutrophil adhesion each were suppressed by tyrosine kinase inhibitors, including genistein (200 μM), but not genistin, its isoflavone analog without tyrosine kinase inhibitory activity. Tyrphostin AG 126, a synthetic selective tyrosine kinase inhibitor, also suppressed ICAM-1 and E-selectin upregulation and neutrophil adhesion, each in a dose-dependent manner, whereas tyrphostin AG 1288 had no effect. Tyrosine phosphorylation of two proteins (85 and 145 kDa in the cytoskeleton fraction) found minutes after TNF-α-stimulation was also inhibited by genistein. These findings suggest that, in endothelial cells, TNF-α upregulates ICAM-1 and E-selectin expression and consequent neutrophil adhesion via protein tyrosine phosphorylation.

scholarly journals Porphyromonas gingivalis Tyrosine Phosphatase Php1 Promotes Community Development and Pathogenicity

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Young-Jung Jung ◽  
Daniel P. Miller ◽  
John D. Perpich ◽  
Zackary R. Fitzsimonds ◽  
Daonan Shen ◽  
...  
Keyword(s):  
Community Development ◽  
Phosphatase Activity ◽  
Tyrosine Phosphorylation ◽  
Porphyromonas Gingivalis ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphorylation ◽  
Tyrosine Phosphatases ◽  
Content Type ◽  
Protein Tyrosine

ABSTRACT Protein-tyrosine phosphorylation in bacteria plays a significant role in multiple cellular functions, including those related to community development and virulence. Metal-dependent protein tyrosine phosphatases that belong to the polymerase and histindinol phosphatase (PHP) family are widespread in Gram-positive bacteria. Here, we show that Porphyromonas gingivalis, a Gram-negative periodontal pathogen, expresses a PHP protein, Php1, with divalent metal ion-dependent tyrosine phosphatase activity. Php1 tyrosine phosphatase activity was attenuated by mutation of conserved histidine residues that are important for the coordination of metal ions and by mutation of a conserved arginine residue, a key residue for catalysis in other bacterial PHPs. The php1 gene is located immediately downstream of the gene encoding the bacterial tyrosine (BY) kinase Ptk1, which was a substrate for Php1 in vitro. Php1 rapidly caused the conversion of Ptk1 to a state of low tyrosine phosphorylation in the absence of discernible intermediate phosphoforms. Active Php1 was required for P. gingivalis exopolysaccharide production and for community development with the antecedent oral biofilm constituent Streptococcus gordonii under nutrient-depleted conditions. In contrast, the absence of Php1 had no effect on the ability of P. gingivalis to form monospecies biofilms. In vitro, Php1 enzymatic activity was resistant to the effects of the streptococcal secreted metabolites pABA and H2O2, which inhibited Ltp1, an enzyme in the low-molecular-weight (LMW) phosphotyrosine phosphatase family. Ptk1 reciprocally phosphorylated Php1 on tyrosine residues 159 and 161, which independently impacted phosphatase activity. Loss of Php1 rendered P. gingivalis nonvirulent in an animal model of periodontal disease. Collectively, these results demonstrate that P. gingivalis possesses active PHP and LMW tyrosine phosphatases, a unique configuration in Gram-negatives which may allow P. gingivalis to maintain phosphorylation/dephosphorylation homeostasis in multispecies communities. Moreover, Php1 contributes to the pathogenic potential of the organism. IMPORTANCE Periodontal diseases are among the most common infections of humans and are also associated with systemic inflammatory conditions. Colonization and pathogenicity of P. gingivalis are regulated by signal transduction pathways based on protein tyrosine phosphorylation and dephosphorylation. Here, we identify and characterize a novel component of the tyrosine (de)phosphorylation axis: a polymerase and histindinol phosphatase (PHP) family enzyme. This tyrosine phosphatase, designated Php1, was required for P. gingivalis community development with other oral bacteria, and in the absence of Php1 activity P. gingivalis was unable to cause disease in a mouse model of periodontitis. This work provides significant insights into the protein tyrosine (de)phosphorylation network in P. gingivalis, its adaptation to heterotypic communities, and its contribution to colonization and virulence.

Erythropoietin induces association of the JAK2 protein tyrosine kinase with the erythropoietin receptor in vivo

Blood ◽  
1994 ◽  
Vol 84 (5) ◽  
pp. 1501-1507 ◽  
Author(s):  
O Miura ◽  
N Nakamura ◽  
FW Quelle ◽  
BA Witthuhn ◽  
JN Ihle ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Immune Complex ◽  
Proximal Region ◽  
Erythropoietin Receptor ◽  
Tyrosine Kinase Domain ◽  
Protein Tyrosine ◽  
Cytoplasmic Region

Abstract Protein tyrosine phosphorylation has been hypothesized to play a key role in the growth signaling induced by erythropoietin (Epo), although the Epo receptor (EpoR), a member of the cytokine receptor superfamily, lacks a tyrosine kinase domain. Recently, the JAK2 tyrosine kinase was shown to be activated on Epo stimulation and to bind to the cytoplasmic domain of EpoR in vitro. To further explore the mechanisms of activation of JAK2 in EpoR-mediated signal transduction, we assessed the conditions for association of JAK2 with EpoR in vivo. Epo stimulation rapidly induced association of JAK2 with the EpoR in an interleukin 3 (IL-3)-dependent cell line transfected with the wild-type EpoR. On Epo stimulation JAK2 also associated with a truncated mutant EpoR (H-mutant), which is mitogenetically active but not tyrosine phosphorylated, indicating that association does not require receptor phosphorylation and occurs in the membrane proximal region. However, association was not detected with mutant receptors inactivated by an internal deletion or a point mutation, Trp282 to Arg, in a membrane- proximal cytoplasmic region (PB or PM4 mutant, respectively). Immune complex kinase assays of anti-EpoR immunoprecipitates also revealed that activated JAK2 associates with the EpoR in Epo-stimulated cells. By this approach, association also occurred with the mitogenically active H mutant but not with the mitogenically inactive PB or PM4 mutants. In the immune complex kinases assays, EpoR, JAK2, and a 150-kD protein were phosphorylated on tyrosine. Taken together, the results further support the hypothesis that, on Epo stimulation, JAK2 associates with the membrane-proximal cytoplasmic region of the EpoR to be activated and induces tyrosine phosphorylation of cellular substrates, including the EpoR, to transduce a growth signal.

scholarly journals Human Sperm Remain Motile After a Temporary Energy Restriction but do Not Undergo Capacitation-Related Events

2021 ◽  
Vol 9 ◽  
Author(s):  
Clara I. Marín-Briggiler ◽  
Guillermina M. Luque ◽  
María G. Gervasi ◽  
Natalia Oscoz-Susino ◽  
Jessica M. Sierra ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Metabolic Pathways ◽  
Energy Recovery ◽  
Human Sperm ◽  
Energy Restriction ◽  
Protein Tyrosine Phosphorylation ◽  
Mouse Sperm ◽  
Protein Tyrosine ◽  
Intracellular Ca

To acquire fertilization competence, mammalian sperm must undergo several biochemical and physiological modifications known as capacitation. Despite its relevance, the metabolic pathways that regulate the capacitation-related events, including the development of hyperactivated motility, are still poorly described. Previous studies from our group have shown that temporary energy restriction in mouse sperm enhanced hyperactivation, in vitro fertilization, early embryo development and pregnancy rates after embryo transfer, and it improved intracytoplasmic sperm injection results in the bovine model. However, the effects of starvation and energy recovery protocols on human sperm function have not yet been established. In the present work, human sperm were incubated for different periods of time in medium containing glucose, pyruvate and lactate (NUTR) or devoid of nutrients for the starving condition (STRV). Sperm maintained in STRV displayed reduced percentages of motility and kinematic parameters compared to cells incubated in NUTR medium. Moreover, they did not undergo hyperactivation and showed reduced levels of ATP, cAMP and protein tyrosine phosphorylation. Similar to our results with mouse sperm, starvation induced increased intracellular Ca2+ concentrations. Starved human sperm were capable to continue moving for more than 27 h, but the incubation with a mitochondrial uncoupler or inhibitors of oxidative phosphorylation led to a complete motility loss. When exogenous nutrients were added back (sperm energy recovery (SER) treatment), hyperactivated motility was rescued and there was a rise in sperm ATP and cAMP levels in 1 min, with a decrease in intracellular Ca2+ concentration and no changes in sperm protein tyrosine phosphorylation. The finding that human sperm can remain motile for several hours under starvation due to mitochondrial use of endogenous metabolites implies that other metabolic pathways may play a role in sperm energy production. In addition, full recovery of motility and other capacitation parameters of human sperm after SER suggests that this treatment might be used to modulate human sperm fertilizing ability in vitro.

Quantification of kinetic changes in protein tyrosine phosphorylation and cytosolic Ca2+ concentration in boar spermatozoa during cryopreservation

2012 ◽  
Vol 24 (4) ◽  
pp. 531 ◽  
Author(s):  
A. Kumaresan ◽  
A. P. Siqueira ◽  
M. S. Hossain ◽  
A. Johannisson ◽  
I. Eriksson ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Tyrosine Phosphorylation ◽  
Mammalian Species ◽  
Protein Tyrosine Phosphorylation ◽  
Protein Tyrosine ◽  
Quantitative Evidence ◽  
Phosphorylated Proteins ◽  
Straight Line ◽  
Cryopreserved Sperm ◽  
Boar Spermatozoa

Protein tyrosine phosphorylation in sperm is associated with capacitation in several mammalian species. Although tyrosine phosphorylated proteins have been demonstrated in cryopreserved sperm, indicating capacitation-like changes during cryopreservation, these changes have not yet been quantified objectively. We monitored tyrosine phosphorylation, intracellular calcium and sperm kinematics throughout the cryopreservation process, and studied the relationships among them in boar spermatozoa. Sperm kinetics changed significantly during cryopreservation: curvilinear velocity, average path velocity and straight line velocity all decreased significantly (P < 0.05). While the percentage of sperm with high intracellular calcium declined (P < 0.05), global phosphorylation increased significantly (P < 0.01). Specifically, cooling to 5°C induced phosphorylation in the spermatozoa. After cooling, a 32-kDa protein not observed in fresh semen appeared and was consistently present throughout the cryopreservation process. While the level of expression of this phosphoprotein decreased after addition of the second extender, frozen–thawed spermatozoa showed an increased expression. The proportion of sperm cells with phosphorylation in the acrosomal area also increased significantly (P < 0.05) during cryopreservation, indicating that phosphorylation might be associated with capacitation-like changes. These results provide the first quantitative evidence of dynamic changes in the subpopulation of boar spermatozoa undergoing tyrosine phosphorylation during cryopreservation.

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