Role of phospholipase A2 in mammalian sperm‐egg fusion: Development of hamster oolemma fusibility by lysophosphatidylcholine

Riffo, Marta S.; Párraga, Mario

doi:10.1002/(sici)1097-010x(19970901)279:1<81::aid-jez8>3.3.co;2-v

Cited by 17 publications

(25 citation statements)

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“…Phospholipase A2 (PLA2) breaks down phosphatidylcholine (PC) to LPC, and it is interesting to note that a PLA2 inhibitor inhibited fertilization envelope formation during sea urchin fertilization but did not block the increase in [Ca11] in or acid efflux/zygote alkalinization (20). Furthermore, Riffo and Parraga (21) suggest that PLA2 activation is important in sperm-egg fusion, inasmuch as LPC addition induced the interspecies fusion of human sperm and the hamster egg and anti-PLA2 antibodies were inhibitory.…”

Section: Lipid Signaling Related To Fertilizationmentioning

confidence: 92%

“…As noted earlier, PLA2 inhibition blocks some fertilization events, and there is evidence that LPC, produced through the action of PLA2 on PC, plays a role in membrane fusion (20,21). Although this should be examined directly, the ?50% drop in total amount LPC during fertilization suggests that high levels of LPC do not play a role in sperm-egg fusion or subsequent cortical granule exocytosis.…”

Section: Lpc Changes In Fertilizationmentioning

confidence: 99%

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Lipid levels in sperm, eggs, and during fertilization in Xenopus laevis

Petcoff

Holland

Stith

2008

Journal of Lipid Research

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Critical developmental periods, such as fertilization, involve metabolic activation, membrane fusion events such as sperm-egg or plasma membrane-cortical granule merger, and production and hydrolysis of phospholipids. However, there has been no large-scale quantification of phospholipid changes during fertilization. Using an enzymatic assay, traditional FA analysis by TLC and gas chromatography, along with a new method of phospholipid measurement involving HPLC separation and evaporative light-scattering detection, we report lipid levels in eggs, sperm, and during fertilization in Xenopus laevis. Sperm were found to contain different amounts of phospholipids as compared with eggs. During fertilization, total phosphatidylinositol, lysophosphatidylcholine, sphingomyelin, and phosphatidylserine decreased, and ceramide increased, whereas there was no change in phosphatidylcholine, cardiolipin, or phosphatidylethanolamine. FA analysis of phospholipids found numerous changes during fertilization. Because there is an increase in sn-1,2-diacylglycerol at fertilization, the FAs associated with this increase and the source of the increase in this neutral lipid were examined. Finally, activation of phospholipase C, phospholipase D, phospholipase A2, autotoxin, and sphingomyelinase at fertilization is discussed. Major goals of the LIPID Metabolites and Pathways Strategy (LIPID MAPS) are to "separate and detect all of the lipids in a specific cell," "to quantitate each of the lipid metabolites present and determine the changes in their levels," and to study lipid metabolic pathways during biological events (1). Characterizing changes in the lipid composition during defined biological events is part of the concept of "functional lipidomics" (2). These fundamental, descriptive studies will facilitate our understanding of how lipids regulate membrane fluidity and fusion, lipid rafts, the cytoskeleton, kinases, and protein binding to membranes (e.g., 3-5) to induce pleiotropic cellular effects.About 15 years ago, quantification of lipid mass changes during maturation of the oocyte to the fertilizable egg, and during fertilization of the egg by sperm, was begun in Xenopus laevis (6-9). Critical developmental events can be isolated in vitro with this model system, and large numbers of gametes can be obtained to provide sufficient amounts of second messengers and lipids. During fertilization, membrane bending and fusion are associated with the acrosome reaction of sperm (wherein the large sperm acrosome undergoes exocytosis upon interaction with layers that cover the egg), with sperm-egg merger, and with subsequent fertilization events such as cortical granule exocytosis (10, 11). Furthermore, both Xenopus and human eggs are arrested in meiosis II (12).Compared with oocytes, one disadvantage of studying eggs is that they have a short life, much less than the estimated time for lipid precursor incorporation to near equilibrium levels (6, 7). Thus, lipid analysis based on label incorporation or turnover is not reliable, and ...

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Section: Lipid Signaling Related To Fertilizationmentioning

confidence: 92%

Section: Lpc Changes In Fertilizationmentioning

confidence: 99%

Lipid levels in sperm, eggs, and during fertilization in Xenopus laevis

Petcoff

Holland

Stith

2008

Journal of Lipid Research

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“…reported (29,38), but the two studies were performed using antibodies with unclear specificity toward the different sPLA 2 isoforms and were thus inconclusive regarding the identity of the human sperm sPLA 2 . Finally, there is evidence suggesting that other PLA 2 s including iPLA 2 β and likely a cPLA 2 member are present in sperm (18,19).…”

Section: Figurementioning

confidence: 99%

“…The fact that addition of LPC during the fertilization step was able to restore the fertilizing potential of sperm capacitated in conditions where mGX was inhibited also supports a role of mGX when secreted during ZP-induced AR. Besides, LPC increases both sperm binding to ZP and sperm-oocyte fusion (37,38). The targets of the mGX metabolites allowing sperm to efficiently fertilize an egg, however, remain to be determined.…”

Section: Figurementioning

confidence: 99%

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Group X phospholipase A2 is released during sperm acrosome reaction and controls fertility outcome in mice

Escoffier¹,

Jemel²,

Tanemoto³

et al. 2010

J. Clin. Invest.

100

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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 A 2 (sPLA 2 ) 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 sPLA 2 (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 sPLA 2 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.

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Proteins of the accessory sex glands associated with the oocyte‐penetrating capacity of cauda epididymal sperm from holstein bulls of documented fertility

Moura

Chapman

Killian

2006

Molecular Reproduction Devel

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We previously reported that accessory sex gland fluid (AGF) from high fertility (HF) bulls influenced the oocyte-penetrating capacity of cauda epididymal sperm from low fertility (LF) bulls, based on in vitro fertilization (IVF) assays. The present study determined if AGF proteins were associated with these effects. Nineteen IVF assays with 12 bulls were grouped as follows. Group I (n = 8): assays where sperm from LF bulls exposed to AGF from HF bulls had greater oocyte penetration than exposed to homologous AGF. Group II (n = 7): sperm from LF bulls to AGF from HF bulls versus homologous AGF showed no significant differences. Group III (n = 4): sperm from LF bulls treated with homologous AGF had greater fertility than sperm treated with AGF from HF bulls. Sire fertility was based on nonreturn rates (NNR) and AGF collected by artificial vagina from bulls with cannulated vasa deferentia. Two-dimensional SDS-PAGE maps of AGF were analyzed by PDQuest and proteins identified by tandem mass spectrometry and Western blots. Differences in spot intensity between AGF of HF and LF bulls were compared across groups of IVF assays (P < 0.05). The expression of BSP A1/A2 and A3, BSP 30 kDa, clusterin, albumin, phospholipase A(2) (PLA(2)), and osteopontin was greater in the AGF of HF bulls in Group I as compared to Groups II and III. Conversely, there was less nucleobindin in the AGF of HF bulls in Group I than in Groups II and III. This is the first report of nucleobindin (58 kDa/pI 5.6) in male reproductive fluids, using both immunoblots and mass spectrometry. Thus, the effect of AGF from HF bulls on epididymal sperm is likely the result of specific proteins expressed in the AGF.

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Role of phospholipase A2 in mammalian sperm‐egg fusion: Development of hamster oolemma fusibility by lysophosphatidylcholine

Cited by 17 publications

References 0 publications

Lipid levels in sperm, eggs, and during fertilization in Xenopus laevis

Lipid levels in sperm, eggs, and during fertilization in Xenopus laevis

Group X phospholipase A2 is released during sperm acrosome reaction and controls fertility outcome in mice

Proteins of the accessory sex glands associated with the oocyte‐penetrating capacity of cauda epididymal sperm from holstein bulls of documented fertility

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