Expression of a Catalytically Inactive Mutant Form of Glutathione Peroxidase 4 (Gpx4) Confers a Dominant-negative Effect in Male Fertility.
The selenoenzyme Gpx4 is essential for early embryogenesis and cell viability for its unique function to prevent phospholipid oxidation. Recently, the cytosolic form of Gpx4 was identified as an upstream regulator of a novel form of non-apoptotic cell death, called ferroptosis, whereas the mitochondrial isoform of Gpx4 was previously shown to be crucial for male fertility. Here, we generated and analyzed mice with a targeted mutation of the active site selenocysteine of Gpx4 (Gpx4_U46S). Mice homozygous for Gpx4_U46S died at the same embryonic stage (E7.5) as Gpx4(-/-) embryos as expected. Surprisingly, male mice heterozygous for Gpx4_U46S presented subfertility. Subfertility was manifested in a reduced number of litters from heterozygous breeding and an impairment of spermatozoa to fertilize oocytes in vitro. Morphologically, sperm isolated from heterozygous Gpx4_U46S mice revealed many structural abnormalities particularly in the spermatozoa midpiece due to improper oxidation and polymerization of sperm capsular proteins and malformation of the mitochondrial capsule surrounding and stabilizing sperm mitochondria. These findings are reminiscent of sperm isolated from selenium-deprived rodents or from mice specifically lacking mitochondrial Gpx4. Due to a strongly facilitated incorporation of Ser in the polypeptide chain as compared with selenocysteine at the UGA codon, expression of the catalytically inactive Gpx4_U46S was found to be strongly increased. Because the stability of the mitochondrial capsule of mature spermatozoa depends on the moonlighting function of Gpx4 both as an enzyme oxidizing capsular protein thiols and as a structural protein, tightly controlled expression of functional Gpx4 emerges as a key for full male fertility.
From the Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrassse 1, 85764 Neuherberg, Germany.
Irina
I
Ingold
Research Unit Analytical Pathology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
Michaela
M
Aichler
From the Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrassse 1, 85764 Neuherberg, Germany.
Elena
E
Yefremova
Department of Molecular Medicine, University of Padova, 35121 Padova, Italy.
Antonella
A
Roveri
From the Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrassse 1, 85764 Neuherberg, Germany.
Katalin
K
Buday
From the Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrassse 1, 85764 Neuherberg, Germany.
Sebastian
S
Doll
From the Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrassse 1, 85764 Neuherberg, Germany.
Adrianne
A
Tasdemir
From the Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrassse 1, 85764 Neuherberg, Germany.
Nils
N
Hoffard
From the Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrassse 1, 85764 Neuherberg, Germany, Deutsches Zentrum für Neurodegenerative Erkrankungen e. V. (DZNE) Standort München, Schillerstrasse 44, 80336 Munich, Germany, Munich Cluster for Systems Neurology (SyNergy) Adolf-Butenandt-Institut Ludwig-Maximilians-Universität München, Schillerstrasse 44, 80336 Munich, Germany, and Technische Universität München-Weihenstephan, Lehrstuhl für Entwicklungsgenetik c/o Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
Wolfgang
W
Wurst
Research Unit Analytical Pathology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
Axel
A
Walch
Department of Molecular Medicine, University of Padova, 35121 Padova, Italy.
Fulvio
F
Ursini
From the Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrassse 1, 85764 Neuherberg, Germany.
José Pedro
JP
Friedmann Angeli
From the Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstrassse 1, 85764 Neuherberg, Germany, marcus.conrad@helmholtz-muenchen.de.
Marcus
M
Conrad
D019943:Amino Acid Substitution; D000818:Animals; D020134:Catalytic Domain; D002478:Cells, Cultured; D020964:Embryo Loss / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005260:Female; D005979:Glutathione Peroxidase / Q000235:genetics* / Q000378:metabolism*; D006579:Heterozygote; D006720:Homozygote; D007248:Infertility, Male / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D017279:Selenocysteine / Q000235:genetics; D012694:Serine / Q000235:genetics; D013091:Spermatogenesis; D013094:Spermatozoa / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure
D017279:Selenocysteine; D012694:Serine; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D005979:Glutathione Peroxidase
selenoprotein, selenium, spermatogenesis, glutathione, peroxidase, mouse genetics, fertilization