Immenschuh Stephan, Baumgart-Vogt Eveline, Tan Melly, Iwahara Shin-ichiro, Ramadori Giuliano, Fahimi H Dariush
Institute of Clinical Chemistry and Pathobiochemistry, University of Giessen, Giessen, Germany.
J Histochem Cytochem. 2003 Dec;51(12):1621-31. doi: 10.1177/002215540305101206.
Heme-binding protein 23 (HBP23), also termed peroxiredoxin (Prx) I, and heme oxygenase-1 (HO-1) are distinct antioxidant stress proteins that are co-ordinately induced by oxidative stress. HBP23/Prx I has thioredoxin-dependent peroxidase activity with high binding affinity for the pro-oxidant heme, while HO-1 is the inducible isoform of the rate-limiting enzyme of heme degradation. We investigated the cellular and subcellular localization of both proteins in rat liver. Whereas by immunohistochemistry (IHC) a uniformly high level of HBP23/Prx I expression was observed in liver parenchymal and different sinusoidal cells, HO-1 expression was restricted to Kupffer cells. By immunoelectron microscopy using the protein A-gold technique, HBP23/Prx I immunoreactivity was detected in cytoplasm, nuclear matrix, mitochondria, and peroxisomes of parenchymal and non-parenchymal liver cell populations. In contrast, the secretory pathway, i.e., the endoplasmic reticulum and Golgi complex, was free of label. As determined by immunocytochemical (ICC) studies in liver cell cultures and by Western and Northern blotting analysis, HBP23/Prx I was highly expressed in cultures of isolated hepatocytes and Kupffer cells. In contrast, HO-1 was constitutively expressed only in Kupffer cell cultures but was also inducible in hepatocytes. These data suggest that HBP23/Prx I and HO-1 may have complementary antioxidant functions in different cell populations in rat liver.
血红素结合蛋白23（HBP23），也称为过氧化物酶（Prx）I，和血红素加氧酶-1（HO-1）是不同的抗氧化应激蛋白，它们在氧化应激下协同诱导产生。HBP23/Prx I具有硫氧还蛋白依赖性过氧化物酶活性，对促氧化剂血红素具有高结合亲和力，而HO-1是血红素降解限速酶的诱导型同工酶。我们研究了这两种蛋白在大鼠肝脏中的细胞和亚细胞定位。通过免疫组织化学（IHC），在肝实质细胞和不同的窦状隙细胞中均观察到HBP23/Prx I表达水平普遍较高，而HO-1表达仅限于库普弗细胞。使用蛋白A-金技术的免疫电子显微镜检查显示，在肝实质和非实质细胞群体的细胞质、核基质、线粒体和过氧化物酶体中检测到HBP23/Prx I免疫反应性。相反，分泌途径，即内质网和高尔基体复合体，没有标记。通过肝细胞培养中的免疫细胞化学（ICC）研究以及蛋白质免疫印迹和Northern印迹分析确定，HBP23/Prx I在分离的肝细胞和库普弗细胞培养物中高表达。相比之下，HO-1仅在库普弗细胞培养物中组成性表达，但在肝细胞中也可诱导表达。这些数据表明，HBP23/Prx I和HO-1在大鼠肝脏的不同细胞群体中可能具有互补的抗氧化功能。
