Complementary regulation of heme oxygenase-1 and peroxiredoxin I gene expression by oxidative stress in the liver.

Heme oxygenase (HO)-1, the inducible isoform of the rate-limiting enzyme of heme degradation, and peroxiredoxin (Prx) I, a thioredoxin-dependent peroxidase, are multifunctional antioxidant stress proteins which are coordinately up-regulated by oxidative stress in cell cultures. HO-1 and Prx I exhibit a different hepatic cellular and subcellular localization. Here, a distinct expression pattern of the two genes was confirmed by in situ hybridization of normal rat liver. Moreover, expression of the HO-1 and Prx I genes was determined in a model of acutely damaged rat liver which was elicited by application of a single dose of carbon tetrachloride (CCl4). The mRNA levels of the HO-1 and Prx I genes were induced in whole livers of CCl4-treated rats with differential kinetics as determined by Northern blot analysis. While HO-1 mRNA was induced up to 48 hr, Prx I exhibited a maximum level of mRNA after 12 hr of treatment with CCl4. CCl4-dependent oxidative stress led to a focal increase of perivenous HO-1 positive liver cells with simultaneous loss of Prx I immunoreactivity. Taken together, the complementary hepatic gene expression pattern of HO-1 and Prx I in response to oxidative stress may suggest a functional interplay of these antioxidant genes.