Division of Molecular Cell Biology, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, Saga 849‑8501, Japan.
Mol Med Rep. 2012 Aug;6(2):379-84. doi: 10.3892/mmr.2012.935. Epub 2012 Jun 6.
Peroxiredoxin (Prx)-4, a secretable endoplasmic reticulum (ER)-resident isoform of the mammalian Prx family, functions as a thioredoxin-dependent peroxidase. It is acknowledged that Prx-4 plays a role in the detoxification of hydrogen peroxide, and potentially other peroxides, which may be generated during the oxidative folding of proteins and oxidative stress in the ER. The present study was undertaken in order to specifically quantify the tissue levels of Prx-4. To accomplish this, an enzyme-linked immunosorbent assay was developed using a specific polyclonal antibody produced by immunizing a rabbit with native recombinant rat Prx-4 protein. The assay was used to detect Prx-4 in the range of 0.1 and 10 ng/ml, and to investigate tissue distribution in rats. Using this immunoassay, we found that the serum levels of Prx-4 were substantially lower in asymptomatic Long-Evans Cinnamon rats, a rat model of Wilson's disease, compared to normal rats. In addition, the treatment of rat hepatoma cells with N-acetylcysteine led to a significant increase in the release of Prx-4 protein into the medium; thus, it appears likely that the secretion of Prx-4 is associated with the redox state within cells. These results suggest that serum Prx-4 has potential for use as a biomarker for hepatic oxidative stress.
过氧化物酶 4（Prx-4）是哺乳动物 Prx 家族的一种可分泌的内质网（ER）驻留同工型，作为一种依赖硫氧还蛋白的过氧化物酶发挥作用。人们已经认识到 Prx-4 在过氧化氢的解毒中发挥作用，并且可能在蛋白质的氧化折叠和 ER 中的氧化应激期间产生其他过氧化物。本研究旨在专门定量 Prx-4 的组织水平。为了实现这一目标，使用通过用天然重组大鼠 Prx-4 蛋白免疫兔子产生的特异性多克隆抗体开发了酶联免疫吸附测定法。该测定法用于检测 0.1 和 10 ng/ml 范围内的 Prx-4，并研究大鼠中的组织分布。使用这种免疫测定法，我们发现无症状的长耳肉桂大鼠（Wilson 病的大鼠模型）的血清 Prx-4 水平明显低于正常大鼠。此外，用 N-乙酰半胱氨酸处理大鼠肝癌细胞导致 Prx-4 蛋白大量释放到培养基中；因此，Prx-4 的分泌似乎与细胞内的氧化还原状态有关。这些结果表明，血清 Prx-4 有可能用作肝氧化应激的生物标志物。
