Glutathione Peroxidases at Work on Epididymal Spermatozoa: An Example of the Dual Effect of Reactive Oxygen Species on Mammalian Male Fertilizing Ability

Abstract

ABSTRACT:The mammalian glutathione peroxidase (GPx) gene family encodes bifunctional enzymes that can work either as classical reactive oxygen species (ROS) scavengers or as thiol peroxidases, thereby introducing disulfide bridges in thiol-containing proteins. These dual effects are nowhere better demonstrated than in epididymal maturing spermatozoa, where the concomitant actions of several GPx ensure the achievement of the structural maturation of sperm cells as well as their protection against ROS-induced damage. We review here the roles played by the sperm-associated forms of GPx4 (mitochondrial GPx4 and nuclear GPx4), the secreted GPx5 protein, and the epithelial proteins GPx1, GPx3, and cellular GPx4, all functioning in the mammalian epididymis at different stages of the sperm's epididymal journey, and in different epididymis compartments.

Why are epididymal tumours so rare?

“…34 This may stem from the epithelial principal cells' expressing high activities of indoleamine-2,3-dioxgenase (IDO) and tryptophan-2,3-dioxgenase (TDO), both of which can incorporate molecular oxygen into their substrates, 35 and from the high number of luminal spermatozoa, which consume oxygen even when concentrated and immotile. 36 Complementing this non-oxidative environment are anti-oxidant enzymes and components removing superoxide radicals and hydrogen peroxide, 37 some of which are reported in the human epididymal proteome. 38,39 These anti-oxidant strategies make excessive oxidative damage to epididymal cell DNA unlikely.…”

Importance of Trace Minerals in the Ratio of Breeding Bull - A Review

“…It is involved in normal spermatogenesis and it is an essential component of a range of selenoproteins, including glutathione peroxidase, thioredoxin reductase and iodothyroninedeiodinase (Noblanc et al, 2011). It also plays a vital role in protecting both the intra-and extra-cellular lipid membranes against oxidative damage.…”

Ochrona przed stresem oksydacyjnym w męskim układzie płciowym

“…Choć cała reakcja jest błyskawiczna, w ciągu s CAT unieszkodliwia nawet do mln cząsteczek H₂O₂, to katalaza wykazuje swe właściwości dopiero przy bardzo wysokim poziomie H₂O₂ [ ]. Na poziomie komórkowym aktywna jest w peroksysomach, mitochondriach, siateczce śródpla-zmatycznej oraz cytozolu, a tkankowym jej obecność wykazano w gonadzie, najądrzu, nasieniu szczura GPX1, cytozolowa i GPX3 osoczowa -występują w formie tetrameru, redukują głównie H₂O₂ oraz nadtlenki lipidów [7], GPX2, inna postać cytozolowej formy enzymu, pierwotnie wykazana w układzie pokarmowym gryzoni [7], GPX4, PHGPX, peroksydaza glutationowa nadtlenków lipidów, monomer, enzym związany z błonami, pełni istotną funkcję w spermatogenezie [7,59,60], GPX5 (epGPX), nie zawiera w centrum katalitycznym selenocysteiny, co jednak nie wpływa negatywnie na jej aktywność antyoksydacyjną [58,59,61].…”