scholarly journals Human sperm subpopulations: relationship between functional quality and protein tyrosine phosphorylation

2004 ◽  
Vol 19 (1) ◽  
pp. 139-146 ◽  
Author(s):  
M.G. Buffone
2017 ◽  
Vol 483 (2) ◽  
pp. 834-839 ◽  
Author(s):  
Aideé S. López-Torres ◽  
María E. González-González ◽  
Esperanza Mata-Martínez ◽  
Fernando Larrea ◽  
Claudia L. Treviño ◽  
...  

Reproduction ◽  
2015 ◽  
Vol 150 (4) ◽  
pp. 257-268 ◽  
Author(s):  
Yuchuan Zhou ◽  
Yanfei Ru ◽  
Huijuan Shi ◽  
Yanjiao Wang ◽  
Bin Wu ◽  
...  

Cholecystokinin (CCK), a peptide hormone and a neurotransmitter, was detected in mature sperm two decades ago. However, the exact role of CCK and the types of CCK receptors (now termed CCK1 and CCK2) in sperm have not been identified. Here, we find that CCK1 and CCK2 receptors are immunolocalized to the acrosomal region of mature sperm. The antagonist of CCK1 or CCK2 receptor strongly activated the soluble adenylyl cyclase/cAMP/protein kinase A signaling pathway that drives sperm capacitation-associated protein tyrosine phosphorylation in dose- and time-dependent manners. But these actions of stimulation were abolished when sperm were incubated in the medium in the absence of HCO3−. Further investigation demonstrated that the inhibitor of CCK1 or CCK2 receptor could accelerate the uptake of HCO3−and significantly elevate the intracellular pH of sperm. Interestingly, the synthetic octapeptide of CCK (CCK8) showed the same action and mechanism as antagonists of CCK receptors. Moreover, CCK8 and the antagonist of CCK1 or CCK2 receptor were also able to accelerate human sperm capacitation-associated protein tyrosine phosphorylation by stimulating the influx of HCO3−. Thus, the present results suggest that CCK and its receptors may regulate sperm capacitation-associated protein tyrosine phosphorylation by modulating the uptake of HCO3−.


Reproduction ◽  
2005 ◽  
Vol 129 (6) ◽  
pp. 697-705 ◽  
Author(s):  
Mariano G Buffone ◽  
Juan C Calamera ◽  
Sandra V Verstraeten ◽  
Gustavo F Doncel

Sperm protein tyrosine phosphorylation has been associated with capacitation, motility changes, zona binding, and fertilizing ability. We previously demonstrated that gradient-isolated human sperm subpopulations differ in their plasma membrane composition, their ability to phosphorylate proteins in tyrosine residues, and their capacity to undergo hyperactivation. In this study, we have characterized capacitation-associated changes in protein tyrosine phosphorylation and membrane fluidity in spermatozoa of asthenozoospermic and normozoospermic patients consulting for infertility. Semen samples were studied at baseline and after a capacitating incubation with or without the addition of a permeable cAMP analog and a phosphodiesterase inhibitor. Basic sperm and computer-assisted motion parameters, hyperactivation, protein tyrosine phosphorylation (immunofluorescence and Western blot), and membrane fluidity (fluorescent Laurdan probe) were the main study parameters. In comparison with normozoospermic and proven-fertile donor semen, asthenozoospermic samples showed lower motility, velocity, and amplitude of lateral head displacement, both originally and after a 6-h capacitating incubation. Unlike those in normal samples, asthenozoospermic spermatozoa were unable to increase protein tyrosine phosphorylation during capacitation. Such impairment, however, was overcome when they were incubated with a membrane-permeable cAMP analog and a phosphodiesterase inhibitor, indicating a possible membrane defect. Confirming this hypothesis, plasma membranes of asthenozoospermic sperm showed decreased fluidity (increased Laurdan polarization), even after a capacitating incubation. In conclusion, spermatozoa from functional asthenozoospermic samples may owe their poor motility, and their inability to properly capacitate and develop hyperactivation, to an impairment in the tyrosine phosphorylation of critical proteins caused by decreased membrane fluidity. These findings suggest a molecular pathogenetic mechanism for a common seminal pathology associated with male infertility.


Author(s):  
Clara I. Marín-Briggiler ◽  
Guillermina M. Luque ◽  
María G. Gervasi ◽  
Natalia Oscoz-Susino ◽  
Jessica M. Sierra ◽  
...  

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.


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