Group X phospholipase A2 is released during sperm acrosome reaction and controls fertility outcome in mice.
Ejaculated mammalian sperm must undergo a maturation process called capacitation before they are able to fertilize an egg. Several studies have suggested a role for members of the secreted phospholipase A2 (sPLA2) family in capacitation, acrosome reaction (AR), and fertilization, but the molecular nature of these enzymes and their specific roles have remained elusive. Here, we have demonstrated that mouse group X sPLA2 (mGX) is the major enzyme present in the acrosome of spermatozoa and that it is released in an active form during capacitation through spontaneous AR. mGX-deficient male mice produced smaller litters than wild-type male siblings when crossed with mGX-deficient females. Further analysis revealed that spermatozoa from mGX-deficient mice exhibited lower rates of spontaneous AR and that this was associated with decreased in vitro fertilization (IVF) efficiency due to a drop in the fertilization potential of the sperm and an increased rate of aborted embryos. Treatment of sperm with sPLA2 inhibitors and antibodies specific for mGX blocked spontaneous AR of wild-type sperm and reduced IVF success. Addition of lysophosphatidylcholine, a catalytic product of mGX, overcame these deficiencies. Finally, recombinant mGX triggered AR and improved IVF outcome. Taken together, our results highlight a paracrine role for mGX during capacitation in which the enzyme primes sperm for efficient fertilization and boosts premature AR of a likely phospholipid-damaged sperm subpopulation to eliminate suboptimal sperm from the pool available for fertilization.
Escoffier
Jessica
J
Grenoble Institute of Neuroscience, INSERM U836, Grenoble, France.
Jemel
Ikram
I
Tanemoto
Akemi
A
Taketomi
Yoshitaka
Y
Payre
Christine
C
Coatrieux
Christelle
C
Sato
Hiroyasu
H
Yamamoto
Kei
K
Masuda
Seiko
S
Pernet-Gallay
Karin
K
Pierre
Virginie
V
Hara
Shuntaro
S
Murakami
Makoto
M
De Waard
Michel
M
Lambeau
Gérard
G
Arnoult
Christophe
C
D020101:Acrosome Reaction; D000818:Animals; D003433:Crosses, Genetic; D005260:Female; D005298:Fertility; D005306:Fertilization; D005307:Fertilization in Vitro; D005786:Gene Expression Regulation; D054509:Group X Phospholipases A2 / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D013094:Spermatozoa / Q000378:metabolism*; D013737:Testis / Q000378:metabolism
D054509:Group X Phospholipases A2