FASEB journal : official publication of the Federation of American Societies for Experimental Biology
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Heme oxygenase (HO) catalyzes the conversion of heme to biliverdin with the release of iron and carbon monoxide. HO-1 is highly inducible by a large number of physical and chemical factors. CoPP is known to be a potent and effective inducer of HO-1 activity in many tissues. ⋯ Transfection with equal amounts of non-Bach1 or non-Nrf2 related control siRNA did not reduce Bach1 or Nrf2 mRNA or protein, confirming the specificity of Bach1- and Nrf2-siRNA in Huh-7 cells. We conclude that the pathway of CoPP-mediated induction of HO-1 involves the repression of Bach1 and up-regulation of the Nrf2 protein by post-transcriptional site(s) of action. Because CoPP, unlike heme, is neither a prooxidant nor a substrate for HO-1, it might be considered as a potential therapeutic agent in situations where up-regulation of HO-1 is desired.