Peroxiredoxin 4knockout results in elevated spermatogenic cell death via oxidative stress

Abstract

Prx (peroxiredoxin) is a multifunctional redox protein with thioredoxin-dependent peroxidase activity. Prx4 is present as a secretory protein in most tissues, whereas in sexually mature testes it is anchored in the ER (endoplasmic reticulum) membrane of spermatogenic cells via an uncleaved N-terminal hydrophobic peptide. We generated a Prx4 knockout mouse to investigate the function of Prx4 in vivo. Prx4(-/y) mice lacking Prx4 expression in all cells were obtained by mating Prx4(flox/+) female mice with Cre-transgenic male mice that ubiquitously expressed Cre recombinase. The resulting Prx4(-/y) male mice were fertile, and most organs were nearly normal in size, except for testicular atrophy. The number of deoxynucleotidyl transferase-mediated dUTP nick end labelling-positive spermatogenic cells was higher in Prx4(-/y) mice than in Prx4(+/y) mice and increased remarkably in response to warming the lower abdomen at 43 degrees C for 15 min. Cells reactive to antibodies against 4-hydroxynonenal and 8-hydroxyguanine were high in the Prx4(-/y) mice and concomitant with elevated oxidation of lipid and protein thiols. The cauda epididymis of Prx4(-/y) mice contained round spermatocytes, which were not found in Prx4(+/y) mice, and displayed oligozoospermia. However, mature spermatozoa from the epididymis of Prx4(-/y) mice exhibited normal fertilization In vitro. Taken together, these results indicate that spermatogenic cells lacking Prx4 are more susceptible to cell death via oxidative damage than their wild-type counterparts. Our results suggest that the presence of Prx4, most likely the membrane-bound form, is important for spermatogenesis, but not an absolute requisite.

Identification and Characterization of Alternatively Transcribed Form of Peroxiredoxin IV Gene That Is Specifically Expressed in Spermatids of Postpubertal Mouse Testis

“…Consistent with previous observations (8,14,16,23), only a 27-kDa immunoreactive protein was detected in all tissues with the exception of the testis, which showed an immunoreactive protein of ϳ29.5 kDa in addition to the 27-kDa protein (supplemental Fig. S1A).…”

“…Animals-Male C57BL/6J mice were obtained from The Jackson Laboratory (Bar Harbor, ME), and Prx IV KO mice were described previously (16). All mice were housed in a temperature-controlled animal room with a 12-h light, 12-h dark cycle.…”

“…The Prx IV gene was mapped to the X chromosome in both humans and rodents (10,15), and Prx IV knock-out (KO) mice were recently generated by deletion of exon 1 of the gene (16). The Prx IV KO mice are fertile, but the males manifest testicular atrophy and increased lipid peroxidation in the testis as well as accelerated spermatogenic cell death under conditions of oxidative stress (16).…”

Protein Folding and Quality Control in the ER

“…For example, ERp57 knockout mice showed embryonic lethality, suggesting that ERp57 has a specific role in early development (Garbi et al 2006;Coe et al 2010). Knockout mice of ERdj5, Prdx4, and Ero1a/b (see later section) showed less severe phenotypes, which suggests that their roles can be compensated for by other factors (Iuchi et al 2009;Hosoda et al 2010;Zito et al 2010a). In addition, some ER proteins appear to possess functions outside the ER, such as in mitochondria or nucleus (P5 and ERp57) (Coppari et al 2002;Kimura et al 2008).…”

Proteomic analysis of oxidative modification in endothelial colony-forming cells treated by hydrogen peroxide

“…Prx4 plays an important role not only in peroxide defense, but also in regulating peroxide-mediated cell signaling. Spermatogenic cells were reported to be more susceptible to cell death via oxidative damage in Prx4-knockout mice (49). Prx4 protects cells from oxidative stress by metabolizing Ero1-generated H 2 O 2 and overoxidation of Prx4 can be caused by increased Ero1 activity in cells (50).…”