Tissue expression and cellular localization of phospholipid hydroperoxide glutathione peroxidase (PHGPx) mRNA in male mice

Abstract

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is an ubiquitous antioxidant enzyme, but the exact expression pattern in mammalian tissues is still unknown. The expression and cellular localization of PHGPx mRNA were examined in male mice using real time-polymerase chain reaction and in situ hybridization techniques. The rank order of PHGPx mRNA expression across tissues exhibiting substantial levels of expression was:testes >> heart > cerebrum > or = ileum > stomach = liver = jejunum > or = epididymis. In testes, PHGPx mRNA was highly expressed in spermiogenic cells and Leydig cells. The signal was also expressed in the molecular layer, Purkinje cell layer, and white matter of cerebellum, the pituicytes of neurohypophysis, the parafollicular cells and follicular basement membrane of thyroid, the exocrine portion of pancreas, the tubular epithelium of kidney, the smooth muscle cells of arteries, and the red pulp of spleen. In the gastrointestinal tract, PHGPx mRNA expression was mainly observed in the keratinized surface epithelium of forestomach, the submucosal glands and serosa layers, and further the Paneth cells of intestines. PHGPx mRNA appeared to be ubiquitously expressed in the parenchyma of heart, liver, and lung. These results indicate that PHGPx exhibits a cell- and tissue-specific expression pattern in mice.

Peroxiredoxin 6: A Bifunctional Enzyme with Glutathione Peroxidase and Phospholipase A2Activities

“…To date, only two enzymes have been shown with the ability to reduce cellular phospholipid hydroperoxides. Phospholipid hydroperoxide glutathione peroxidase (GPx4), the first enzyme described with this activity, is highly expressed in testis, where it appears to also have a structural role, but is expressed at much lower levels in other organs such as the lung, where antioxidant defense is crucial (2,93). More recently, Prdx6 also has been shown to reduce phospholipid hydroperoxides (21).…”

“…Subsequently, recombinant protein generated in Escherichia coli was shown to have both peroxidase and PLA 2 activities (6,34). Before the consensus on nomenclature, the protein had been called nonselenium GSH peroxidase (86), aiPLA 2 (38), 1-Cys Prdx (34), antioxidant protein 2 (AOP2) (75), Clara cell protein 26 (CC26), and p29 (47), whereas the gene in addition to ORF6 (64) has been called LTW4 (30) and keratinocyte growth factor (KGF)-regulated gene 1 (24).…”

“…These proteins, based on identity of the catalytic center, have been described in archaea, bacteria, parasites, yeast, insects, mollusks, amphibians, birds, and other orders although differences exist with respect to activity and structure compared with the mammalian enzymes (66). As examples, yeast 1-Cys Prdx is thioredoxin dependent, unlike the mammalian enzymes, whereas nonmammalian species show considerable heterogeneity in the amino acid sequence corresponding to the 1-Cys Prdx lipase motif (66); whether any of these alternate motifs support PLA 2 activity is yet to be determined. Several reviews of Prdx6 have been published previously (53,66,73,84).…”

Effects of Resistance Exercise Training on Antioxidant Enzyme and GLUT 8 Expression in Testes of Type 2 Diabetic Rats

“…14 The phospholipid hydroperoxide GPx (PHGPx) is one of the most important GPx isoforms in a testicular context and is highly expressed in both spermatogenic and Leydig cells. 15 Since most forms of GPx are selenium dependent it is possible to gauge the importance of these enzymes in the support of testicular function by examining the impact of selenium deficiency on male reproduction. Animals fed on a selenium deficient diet exhibit a significant reduction of testicular GPx activity and an accompanying loss of germ cells from the germinal epithelium of the testes.…”

Phospholipid hydroperoxide glutathione peroxidase gene is regulated via an estrogen and estrogen receptor signaling in cultured mouse fetuses

“…PHGPx is distributed in a variety of adult and embryonic tissues (Schneider et al 2006;Baek et al 2007a). PHGPx heterozygous mice appear to be normal even though they have a low level of PHGPx, whereas the embryos of PHGPx homozygous mice die between embryonic days 7.5 and 8.5 Yant et al 2003), thereby indicating that PHGPx is an essential enzyme in embryogenesis.…”