Recovery of redox homeostasis altered by CuNPs in H4IIE liver cells does not reduce the cytotoxic effects of these NPs: An investigation using aryl hydrocarbon receptor (AhR) dependent antioxidant activity. (25th February 2015)

• Record Type: Journal Article
• Authors: Connolly, Mona; Fernández-Cruz, María Luisa; Navas, José María
• Is Part Of: Chemico-biological interactions. Volume 228(2015)
• Page Start: 57
• Page End: 68
• Publication Date: 2015-02-25
• Subjects: CuNP copper nanoparticle -- ROS reactive oxygen species -- AhR aryl hydrocarbon receptor -- ßNF ß-Naphthoflavone -- αNF α-Naphthoflavone -- GST glutathione-S-transferase -- GSH glutathione -- GSSG oxidised glutathione -- Nrf2 nuclear factor erythroid-2-related factor -- HO-1 heme oxygenase-1 -- SnPP tin protoporphyrin IX -- TEM transmission electron microscopy -- AREs anti-oxidant response elements -- XREs xenobiotic response elements -- LOEC lowest observed effect concentration -- CYP1A1 cytochrome P450, family 1, subfamily A, polypeptide 1 -- RR resazurin reduction -- EROD 7-ethoxyresorufin-O-deethylase -- MTT 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromide -- P/S penicillin and streptomycin -- EMEM Eagle Minimum Essential Medium -- NEAA non-essential amino acids -- BSA bovine serum albumin -- DLS dynamic light scattering -- PBS phosphate-buffered saline -- FBS foetal bovine serum -- NADPH β-nicotinamide adenine dinucleotide 2′-phosphate reduced tetrasodium salt hydrate; Copper nanoparticles (CuNPs) -- Oxidative stress -- H4IIE -- Aryl hydrocarbon receptor (AhR) -- ß-Naphthoflavone (ßNF) -- Co-incubation; Biochemistry -- Periodicals; Toxicological chemistry -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biochimie -- Périodiques; Toxicologie biochimique -- Périodiques; 572
• DOI: 10.1016/j.cbi.2015.01.012
• Languages: English
• ISSNs: 0009-2797

Abstract

Highlights: Investigating oxidative stress as a mechanism of cytotoxicity of CuNPs. CuNPs induce oxidative stress in H4IIE cells. Upregulation of AhR dependent antioxidant defence abrogates ROS induced by CuNPs. Evidence of non-oxidative stress mediated cytotoxicity of CuNPs. Implications for using oxidative stress as mechanistic paradigm for NP cytotoxicity. Abstract: The generation of reactive oxygen species (ROS) and consequent oxidative stress is regarded as a relevant mechanism for nanoparticle toxicity. In cells, the activation of the aryl hydrocarbon receptor (AhR) triggers a cascade of defence responses against oxidative stress. By increasing AhR dependent cellular anti-oxidant activity, we tested the extent to which the cytotoxic effect of copper nanoparticles (CuNPs) is governed by oxidative stress. H4IIE rat hepatoma cells were challenged with high ROS levels after exposure to CuNPs, while the AhR-induced cellular anti-oxidant defence was simultaneously activated by the AhR ligand beta-Naphthoflavone (ßNF). Activation of phase II detoxification enzymes (as glutathione-S-transferases, GSTs) and anti-oxidants (glutathione, GSH) led to a complete abrogation of CuNP-induced ROS production. However, a concurrent reduction in cytotoxicity was not detected, thereby indicating that CuNPs exert non-oxidative stress mediated cytotoxic effects. Transmission electron microscopy analysis pointed to a direct physical perturbation of cellular structures by CuNPs, thus contributing to their cytotoxicity. Our observations highlight that distinct mechanisms underlie the toxicity of ions and NPs and indicate that while ROS elicitation is CuNP-specific, the cytotoxic action of these particles may not be directly related to their pro-oxidative activity. These findings have important implications with respect to the oxidative stress paradigm used to explain NP toxicity.