Platelet‐activating factor induces acrosome reaction via the activation of extracellular signal‐regulated kinase in human spermatozoa

Andrologia ◽  
2020 ◽  
Vol 52 (5) ◽  
Author(s):  
Haitao Wu ◽  
Jing Gao ◽  
Xia Wang ◽  
Tsz Ying Leung ◽  
Yong‐Gang Duan ◽  
...  
Keyword(s):  
Acrosome Reaction ◽  
Platelet Activating Factor ◽  
Human Spermatozoa ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal

scholarly journals β-Arrestin 1 Participates in Platelet-Activating Factor Receptor-Mediated Endocytosis of Streptococcus pneumoniae

2005 ◽  
Vol 73 (12) ◽  
pp. 7827-7835 ◽  
Author(s):  
Jana N. Radin ◽  
Carlos J. Orihuela ◽  
Gopal Murti ◽  
Christopher Guglielmo ◽  
Peter J. Murray ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Platelet Activating Factor ◽  
Eukaryotic Cells ◽  
Adapter Protein ◽  
Extracellular Signal Regulated Kinase ◽  
Cos Cells ◽  
Impaired Ability ◽  
Extracellular Signal ◽  
Platelet Activating Factor Receptor ◽  
Portal Of Entry

ABSTRACT Pneumococci traverse eukaryotic cells within vacuoles without intracytoplasmic multiplication. The platelet-activating factor receptor (PAFr) has been suggested as a portal of entry. Pneumococci colocalized with PAFr on endothelial cells and PAFr−/− mice showed a substantially impaired ability to support bacterial translocation, particularly from blood to brain. Pneumococci-induced colocalization of PAFr and β-arrestin 1 at the plasma membrane of endothelial cells and PAFr-mediated pneumococcal uptake in transfected COS cells were greatly increased by cotransfection with the scaffold/adapter protein β-arrestin 1. Activation of extracellular signal-regulated kinase kinases was required for uptake and was limited to the cytoplasmic compartment, consistent with activation by β-arrestin rather than PAFr. Uptake of the pneumococcal vacuole involved clathrin, and half the bacteria proceeded into vacuoles marked by Rab5 and later Rab7, the classical route to the lysosome. Overexpression of β-arrestin in endothelial cells decreased colocalization with Rab7. We conclude that the association of β-arrestin with the PAFr contributes to successful translocation of pneumococci.

Melatonin protects human spermatozoa from apoptosis via melatonin receptor– and extracellular signal–regulated kinase-mediated pathways

2011 ◽  
Vol 95 (7) ◽  
pp. 2290-2296 ◽  
Author(s):  
Javier Espino ◽  
Águeda Ortiz ◽  
Ignacio Bejarano ◽  
Graciela M. Lozano ◽  
Fabian Monllor ◽  
...  
Keyword(s):  
Human Spermatozoa ◽  
Melatonin Receptor ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal

scholarly journals Stimulation of platelet-activating factor synthesis by progesterone and A23187 in human spermatozoa

1993 ◽  
Vol 292 (1) ◽  
pp. 209-216 ◽  
Author(s):  
E Baldi ◽  
C Falsetti ◽  
C Krausz ◽  
G Gervasi ◽  
V Carloni ◽  
...  
Keyword(s):  
Acrosome Reaction ◽  
Platelet Activating Factor ◽  
Human Sperm ◽  
Human Spermatozoa ◽  
Acetate Incorporation ◽  
Acid Release ◽  
Similar Kinetic ◽  
Mammalian Spermatozoa ◽  
Stimulation Of

The presence of platelet-activating factor (PAF) has been demonstrated recently in mammalian spermatozoa, together with evidence for a role of this phospholipid in enhancing sperm motility and fertilizing ability. To investigate whether PAF synthesis and release occurs in human spermatozoa following incubation with stimuli that induce acrosome reaction, spermatozoa were incubated with progesterone and A23187, two known inducers of the exocytotic event. PAF synthesis (remodelling pathway) was assessed by [3H]acetate incorporation into PAF. Treatment of spermatozoa with progesterone and A23187 resulted in an increase of [3H]acetate incorporation into PAF. Most of the newly synthesized [3H]PAF formed in response to acrosome reaction was found in the supernatant, suggesting a release of the phospholipid from spermatozoa. PAF-like material extracted from human spermatozoa was able to induce aggregation of rabbit platelets and showed identical retention time and the same ion m/e values as authentic PAF when analysed with g.c.-m.s. Lyso-PAF:acetyl-CoA acetyltransferase (EC 2.3.1.67) activity in human spermatozoa was also studied and showed similar kinetic parameters to those described for other cell systems. Stimulation of spermatozoa with progesterone and A23187 induced an increase of [3H]arachidonic acid release, suggesting an activation of phospholipase A. In conclusion, our results demonstrated increased production and release of PAF in human sperm following stimulation with progesterone and A23187 and suggest a role for this phospholipid in the activation of spermatozoa.

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