title: Group X secreted phospholipase A₂ specifically decreases sperm motility in mice.
abstract: Different mammalian secreted phospholipases A(2) (sPLA(2) s) are expressed in male reproductive organs and/or in sperm cells but their cellular functions are still not fully characterized. Because several reports indicate a link between cellular lipids and sperm motility, we have investigated the effect of mouse group IIA, IID, IIE, V, and X sPLA(2) s on sperm motility. Among these enzymes, only mouse group X sPLA(2) (mGX sPLA(2) ) acts as a potent inhibitor of sperm motility that decreases track speed (VCL) and lateral displacement of the head (ALH) of both noncapacitated and capacitated sperm. The inhibitory effect of mGX sPLA(2) is dependent on its enzymatic activity because (i) both the proenzyme form of mGX sPLA(2) (pro-mGX) and the H48Q mutant of mGX sPLA(2) have very weak enzymatic activity and are unable to modulate sperm motility and (ii) LY329722, a specific inhibitor of sPLA(2) s, blocks the inhibitory effect of mGX sPLA(2) . Moreover, mGX sPLA(2) exerts a gradual potency on sperm subpopulations with different velocities, an effect which may be linked to the heterogeneity of lipid composition in these sperm subpopulations. Finally, we found that endogenous mGX sPLA(2) released during spontaneous acrosome reaction modulates sperm motility of capacitated sperm. Together, our results suggest a new role of sPLA(2) in sperm physiology where the sPLA2 selects a sperm subpopulation for fertilization based on its effect on sperm motility.
authors.affiliation: INSERM, U836, Grenoble, France.
authors.forename: Jessica
authors.initials: J
authors.lastname: Escoffier
authors.forename: Virginie J
authors.initials: VJ
authors.lastname: Pierre
authors.forename: Ikram
authors.initials: I
authors.lastname: Jemel
authors.forename: Léa
authors.initials: L
authors.lastname: Munch
authors.forename: Zied
authors.initials: Z
authors.lastname: Boudhraa
authors.forename: Pierre F
authors.initials: PF
authors.lastname: Ray
authors.forename: Michel
authors.initials: M
authors.lastname: De Waard
authors.forename: Gérard
authors.initials: G
authors.lastname: Lambeau
authors.forename: Christophe
authors.initials: C
authors.lastname: Arnoult
mesh_terms: D000177:Acrosome / Q000201:enzymology; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D015536:Down-Regulation / Q000502:physiology*; D004789:Enzyme Activation / Q000502:physiology; D004822:Epididymis / Q000201:enzymology; D005306:Fertilization / Q000502:physiology; D054509:Group X Phospholipases A2 / Q000378:metabolism / Q000502:physiology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011467:Prostate / Q000201:enzymology; D012661:Semen / Q000201:enzymology; D013075:Sperm Capacitation / Q000502:physiology; D013081:Sperm Motility / Q000502:physiology*; D013082:Sperm Tail / Q000201:enzymology
chemical_list: D054509:Group X Phospholipases A2; C516366:Pla2g10 protein, mouse