Sialic Acid in Purified Human Sperm

Oshio, Shigeru; Kaneko, Shohei; Iizuka, R; Mohri, Hideo

doi:10.3109/01485018708988487

Cited by 7 publications

(3 citation statements)

References 18 publications

(9 reference statements)

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“…In earlier investigations conducted to identify the types of gangliosides in the sperm membrane, endogenous mono-, di-and trisialogangliosides (GM3, GM1, GD1a, GD1b and GT1b) have been observed in animal 23 and human spermatozoa 24 at low concentrations of approximately 1 mg-5 mg per 100 million spermatozoa, 43 although their exact function has not been completely elucidated.…”

Section: Gangliosides and Spermatozoamentioning

confidence: 99%

Protective effects of exogenous gangliosides on ROS-induced changes in human spermatozoa

Gavella¹,

Lipovac²

2013

Asian J Androl

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This article summarizes the available evidence on the efficacy of gangliosides to reduce the degree of reactive oxygen species (ROS)-mediated damage. The antioxidative efficacy of exogenous gangliosides in protecting different cells encouraged us to examine their ability to protect human spermatozoa. Gangliosides are sialic acid-containing glycosphingolipids with strong amphiphilic character due to the bulky headgroup made of several sugar rings with sialic acid residues and the double-tailed hydrophobic lipid moiety. The amphiphilicity of gangliosides allows them to exist as micelles in aqueous media when they are present at a concentration above their critical micellar concentration. The protective effect of ganglioside micelles on spermatozoa is believed to stem from their ability to scavenge free radicals and prevent their damaging effects. In our study, we particularly focused our attention on the protective effect of ganglioside micelles on DNA in human spermatozoa exposed to cryopreservation. The results indicate that ganglioside micelles can modulate the hydrophobic properties of the sperm membrane to increase tolerance to DNA fragmentation, thus protecting the DNA from cryopreservation-induced damage. Further actions of ganglioside micelles, which were documented by biochemical and biophysical studies, included (i) the modulation of superoxide anion generation by increasing the diffusion barrier for membrane events responsible for signal translocation to the interior of the cell; (ii) the inhibition of iron-catalysed hydroxyl radical formation due to the iron chelation potential of gangliosides; and (iii) inhibition of hydrogen peroxide diffusion across the sperm membrane.

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Section: Gangliosides and Spermatozoamentioning

confidence: 99%

Protective effects of exogenous gangliosides on ROS-induced changes in human spermatozoa

Gavella¹,

Lipovac²

2013

Asian J Androl

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“…23 This observation is not surprising because Sg has a very basic isoelectric point (pI > 9.5) 1,9 and the surface of spermatozoa has a high content of acidic proteins (such as sialylated proteins). 24 This ionic binding is strong because, even after two consecutive Percoll (GE Healthcare Bio-Sciences, Bare d' Urfe, Canada) washes (to maximize the removal of seminal plasma proteins loosely associated with the plasma membrane), Sg and/or related antigens are detected in spermatozoa, in both Triton-soluble and Triton-insoluble (Sigma Chemical Co., St. Louis, MO) fractions (immunoblotting data). 1 Furthermore, a polypeptide (19 kd) that appears to be a proteolytic product of Sg from the N-terminal domain was found in human sperm nuclei.…”

Section: Sg and Its Roles In Semenmentioning

confidence: 99%

Semenogelin, the Main Protein of the Human Semen Coagulum, Regulates Sperm Function

Lamirande¹

2007

Semin Thromb Hemost

117

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Semenogelin (Sg), the main component of the human semen coagulum, is an important and versatile protein acting on several sperm parameters, both as intact or degraded Sg. Sg originates mostly from seminal vesicle and probably is responsible for sperm immobilization in the seminal coagulum. Purified Sg can be cross-linked by transglutaminase or phosphorylated by kinases, but the actual occurrence of these reactions in reproductive physiology is not clear. Experimental evidence demonstrates that prostate-specific antigen (PSA) rapidly cleaves Sg, an event temporally associated with semen liquefaction and initiation of sperm motility. Sg and its degradation peptides participate in various processes including Zn +2 shuttling, antibacterial activity, hyaluronidase activation, and so on. Sg inhibits sperm motility at the concentration found in the coagulum, but the rapid processing by PSA allows initiation of movement. The mechanism of Sg action and its targets are not known, but improper Sg degradation decreases fertility. Sg and its degradation peptides block sperm capacitation and associated events at concentrations much lower than those of seminal plasma and could play important role in preventing premature capacitation. The effects of Sg are dependent on time and proteolysis due to PSA, and any imbalance may affect sperm physiology and fertility.

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“…Semen samples were diluted with sperm culture buffer (Hepes-buffered Hank's solution, pH 7.4) (Oshio et al, 1987) in a ratio of 1:10 and the sperm were sedimented by centrifugation at 400 g for 5 min. The supernatant was discarded, the sperm pellet resuspended gently in buffer and recentrifuged.…”

Section: Superoxide Anion Generation Assaymentioning

confidence: 99%

Effect of pentoxifylline on superoxide anion production by human sperm

1991

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The in-vitro effect of pentoxifylline, a methylxanthine derivative, on superoxide anion generation by sperm was studied in 27 men with superoxide anion production ranging from 0.57 to 13.8 nmoles 02-. per 10(6) sperm. Superoxide anion release stimulated by phorbol myristate acetate, a potent activator of oxygen radical generation, was reduced by 29-72% following the addition of 10 mM pentoxifylline. The inhibitory effect of this millimolar concentration of the drug did not depend on the initial superoxide production in the presence of phorbol myristate acetate. These results point to a potential use for pentoxifylline in the treatment of male infertility in men with an increased superoxide anion generation capacity.

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Sialic Acid in Purified Human Sperm

Cited by 7 publications

References 18 publications

Protective effects of exogenous gangliosides on ROS-induced changes in human spermatozoa

Protective effects of exogenous gangliosides on ROS-induced changes in human spermatozoa

Semenogelin, the Main Protein of the Human Semen Coagulum, Regulates Sperm Function

Effect of pentoxifylline on superoxide anion production by human sperm

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