Cholesterol Efflux Alters Lipid Raft Stability and Distribution During Capacitation of Boar Spermatozoa1

Shadan, Sadaf; James, P S; Howes, E. A.; Jones, Roy

doi:10.1095/biolreprod.103.026435

Cited by 152 publications

(137 citation statements)

References 76 publications

(81 reference statements)

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“…However, incubation in the sperm capacitation media formulated for these studies elicited a marked redistribution of CTB staining to one that was restricted to the periacrosomal region of the sperm head. This result shares a striking similarity to previous observations of the GM1 ganglioside localisation reported in boar, human, and mouse sperm following incubation under capacitating conditions (Shadan et al 2004, Nixon et al 2010.…”

Section: Resultssupporting

confidence: 90%

Capacitation in the presence of methyl-β-cyclodextrin results in enhanced zona pellucida-binding ability of stallion spermatozoa

et al. 2014

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While IVF has been widely successful in many domesticated species, the development of a robust IVF system for the horse remains an elusive and highly valued goal. A major impediment to the development of equine IVF is the fact that optimised conditions for the capacitation of equine spermatozoa are yet to be developed. Conversely, it is known that stallion spermatozoa are particularly susceptible to damage arising as a consequence of capacitation-like changes induced prematurely in response to semen handling and transport conditions. To address these limitations, this study sought to develop an effective system to both suppress and promote the in vitro capacitation of stallion spermatozoa. Our data indicated that the latter could be achieved in a bicarbonate-rich medium supplemented with a phosphodiesterase inhibitor, a cyclic AMP analogue, and methyl-b-cyclodextrin, an efficient cholesterolwithdrawing agent. The populations of spermatozoa generated under these conditions displayed a number of hallmarks of capacitation, including elevated levels of tyrosine phosphorylation, a reorganisation of the plasma membrane leading to lipid raft coalescence in the peri-acrosomal region of the sperm head, and a dramatic increase in their ability to interact with heterologous bovine zona pellucida (ZP) and undergo agonist-induced acrosomal exocytosis. Furthermore, this functional transformation was effectively suppressed in media devoid of bicarbonate. Collectively, these results highlight the importance of efficient cholesterol removal in priming stallion spermatozoa for ZP binding in vitro.

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Section: Resultssupporting

confidence: 90%

Capacitation in the presence of methyl-β-cyclodextrin results in enhanced zona pellucida-binding ability of stallion spermatozoa

et al. 2014

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“…Incubation of Percoll-washed sperm in an IVF medium caused the redistribution of both lipid raft marker proteins into the more confined region of the apical ridge and the labelling appears as a clustering of the punctuated structures that were observed prior to the incubation (van Gestel et al, 2005a). Similar dynamics were described by other groups (Shadan et al, 2004;Cross, 2004;Selvaraj et al, 2007) Interestingly, it is possible to isolate a detergent resistant membrane (DRM) fraction at 4°C using 0.1% Triton X-100 or similar detergent strength buffers. The non-solubilized membranes floated over a discontinuous density gradient and this floating fraction containing the DRM.…”

Section: Sperm Membrane Microdomainssupporting

confidence: 56%

Sperm head membrane reorganisation during capacitation

Gadella¹,

Tsai²,

Boerke³

et al. 2008

Int. J. Dev. Biol.

172

150

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The sperm cell has a characteristic polarized morphology and its surface is also highly differentiated into different membrane domains. Junctional protein ring structures seal the surface of the mid-piece from the head and the tail respectively and probably prevent random diffusion of membrane molecules over the protein rings. Despite the absence of such lateral diffusion-preventing structures, the sperm head surface is also highly heterogeneous. Furthermore, lipid and membrane protein ordering is subjected to changes when sperm become capacitated. The forces that maintain the lateral polarity of membrane molecules over the sperm surface, as well as those that cause their dynamic redistribution, are only poorly understood. Nevertheless, it is known that each of the sperm head surface regions has specific roles to allow sperm to fertilize the oocyte: a specific region is devoted to zona pellucida binding, a larger area of the sperm head surface is involved in the acrosome reaction (intracellular fusion), while yet another region is involved in egg plasma membrane binding and fertilization fusion (intercellular membrane fusion). All three events occur in the area of the sperm head where the plasma membrane covers the acrosome. Recently, lipid ordered microdomains (lipid rafts) were discovered in membranes of many biological specimens including sperm. In this review, we cover the latest insights about sperm lipid raft research and discuss how sperm lipid raft dynamics may relate to sperm-zona binding and the zona-induced acrosome reaction.

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“…Our results show that GM1 is located at the postacrosomal region and tail of all ram spermatozoa. Furthermore, we were unable to observe changes in GM1 location associated with capacitation, although a trend toward the reorganization of GM1 has been suggested in methyl-beta-cyclodextrin-induced capacitated boar sperm [31].…”

Section: Discussioncontrasting

confidence: 84%

“…Following in vitro capacitation, membrane rafts become highly enriched in zona binding proteins [28][29][30]. However, contradictory results have been reported, and although some authors have described a redistribution of DRMs after in vitro capacitation [29][30][31], others [32] found no change in the distribution of raft markers after the induction of this process.…”

Section: Introductionmentioning

confidence: 99%

Remodelling of Lipid Rafts during In vitro Capacitation and Acrosome Reaction of Ram Spermatozoa

Colás¹

2013

Biochem Anal Biochem

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Background: Lipid rafts are often known as Detergent-Resistant Microdomains (DRMs). We report for the first time the presence of two lipid raft markers, caveolin-1 and ganglioside GM1, on the ram sperm surface, and the effect of in vitro capacitation and acrosome reaction on these marker distributions, the protein content and lipid composition of DRM and non-DRM fractions. Methods:Caveolin-1 and ganglioside GM1 were evidenced by immunocytochemical and fluorescence analysis, respectively. DRM and non-DRM fractions were separated by an OptiPrep TM density gradient. Cholesterol by fluorometry, GM1 by peroxidase reaction, protein content by spectrophotometry, and fatty acid profiling by gas chromatography were determined.Results: Caveolin-1 was evidenced at the acrosome of 59.2 ± 4.3% fresh spermatozoa, and the proportion of stained cells increased (P<0.05) after capacitation. GM1 was detected at the post-acrosome and tail of all spermatozoa, and no change was found after capacitation. Cholesterol and GM1 were distributed all along the gradient, with a peak in DRM fractions. A higher proportion (P<0.001) of saturated fatty acids was found in DRM fractions, confirmed by the unsaturation index and a higher lipid/protein ratio. In vitro capacitation induced a decrease in the content of saturated fatty acids in both DRM (P<0.001) and non-DRM (P<0.01) fractions. Polyunsaturated fatty acids increased in DRMs after the acrosome reaction. All treatments resulted in lower content of cholesterol and proteins in DRM (P<0.01) and non-DRM fractions (P<0.001), and a higherGM1 content in DRMs (P < 0.05). Conclusions:Lipid raft-like microdomains were isolated in a discrete region of the gradient. Their high content of saturated fatty acids confers a highly ordered environment. Their composition is modified during in vitro capacitation and acrosome reaction. General significance:These results represent the first characterization of ram sperm DRM, and may contribute to a better understanding of the sperm fertilizing potential acquisition mechanism.

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Cholesterol Efflux Alters Lipid Raft Stability and Distribution During Capacitation of Boar Spermatozoa1

Cited by 152 publications

References 76 publications

Capacitation in the presence of methyl-β-cyclodextrin results in enhanced zona pellucida-binding ability of stallion spermatozoa

Capacitation in the presence of methyl-β-cyclodextrin results in enhanced zona pellucida-binding ability of stallion spermatozoa

Sperm head membrane reorganisation during capacitation

Remodelling of Lipid Rafts during In vitro Capacitation and Acrosome Reaction of Ram Spermatozoa

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