Peroxiredoxin II (Prdx II, a typical 2-Cys Prdx) has been originally isolated from erythrocytes, and its structure and peroxidase activity have been adequately studied. Mice lacking Prdx II proteins had heinz bodies in their peripheral blood, and morphologically abnormal cells were detected in the dense red blood cell (RBC) fractions, which contained markedly higher levels of reactive oxygen species (ROS). In this study, a labeling experiment with the thiol-modifying reagent biotinylated iodoacetamide (BIAM) in Prdx II-/- mice revealed that a variety of RBC proteins were highly oxidized. To identify oxidation-sensitive proteins in Prdx II-/- mice, we performed RBC comparative proteome analysis in membrane and cytosolic fractions by nano-UPLC-MSE shotgun proteomics. We found oxidation-sensitive 54 proteins from 61 peptides containing cysteine oxidation, and analyzed comparative expression pattern in healthy RBCs of Prdx II+/+ mice, healthy RBCs of Prdx II-/- mice, and abnormal RBCs of Prdx II-/- mice. These proteins belonged to cellular functions related with RBC lifespan maintain, such as cytoskeleton, stress-induced proteins, metabolic enzymes, signal transduction, and transporters. Furthermore, protein networks among identified oxidation-sensitive proteins were analyzed to associate with various diseases. Consequently, we expected that RBC proteome might provide clues to understand redox-imbalanced diseases.
(-)-Epigallocatechin 3-gallate (EGCG) is a potent antioxidant polyphenol in green tea that acts as an anticancer agent via both direct and indirect pathways. Although the relationship between EGCG's anticancer effects and its antioxidant activity is not fully understood, it is known that EGCG stimulates production of reactive oxygen species (ROS), which induce oxidative stress leading to cell death. In IM9 multiple myeloma cells, EGCG acted in a dose- and time-dependent manner to induce apoptotic cell death. Among the antioxidant enzymes expressed in IM9 cells, levels of peroxiredoxin V (PrdxV) were selectively and significantly reduced by EGCG. Moreover, the ROS scavenger NAC completely inhibited EGCG-induced apoptosis and PrdxV reduction, while overexpression of PrdxV, but not a Prdx(VC48S) mutant, protected IM9 cells from EGCG-induced apoptosis. EGCG-induced reductions in cell viability and PrdxV levels were also observed in primary CD138+ multiple myeloma cells from patients. These results suggest that PrdxV is a key target via which EGCG mediates its anticancer effects.
Peroxiredoxin II knockout (Prdx II(-/-)) mice had a spontaneous phenotype of hemolytic anemia. In this study, we found that Ter-119(+)CD71(+) cells increased in Prdx II(-/-) mice bone marrow (BM) at 8 weeks of age. We examined the differential expression profiles to bone marrow cells (BMCs) between Prdx II(+/+) and Prdx II(-/-) mice using a cDNA microarray. We identified the 136 candidates were differentially expressed a greater twofold increase or decrease than EPO receptor. In this study, we focused on the up-regulated NBPs during erythropoietic differentiation. According to cDNA microarray results, six NBPs except zfp-127 were up-regulated during erythropoiesis in Prdx II(-/-) mice. Among the six candidates, eIF3-p44, hnRNPH1, G3bp, and Zfpm-1 were dramatically increased at day 7 of the in vitro erythropoietic differentiation of human CD34(+) cells. However, DJ-1 and Rbm3 were slightly increased only at day 12. Our results suggest that up-regulated NBPs might be involved during erythropoietic differentiation.
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