Copper activates the NF-κB pathway in vivo

Previous results indicated that intravenous injection of copper in the form of a copper-histidine complex in rats triggers the transcriptional induction of the inducible form of nitric oxide synthase (NOS-II). Here, the authors demonstrate that copper activates the transcription factor NF-κB in the liver and lung tissues of rats, and that this effect is mediated by oxidative stress, since all copper-induced changes, which include histological alterations, formation of nitrotyrosines, vascular pressure drop, production of tumor necrosis factor-α (TNF-α), induction of NOS-II and nitrites, are readily prevented by pretreatment of the animals with the antioxidant tempol. By using electrophoretic mobility shift assays, the p50/p65 dimer and higher molecular weight aggregates have been found to be involved in the copper-induced NF-κB activation. COX-2, a NF-κB-dependent gene involved in the inflammatory response, was also transcriptionally induced by copper, this effect being reduced in the presence of tempol. These results suggest that a physiopathological status, characterized by hypercupremic situations, may lead to the onset of inflammation through production of ROS and activation of NF-κB.