Role of the Nrf2-heme oxygenase-1 pathway in silver nanoparticle-mediated cytotoxicity
- Yeungnam University, College of Pharmacy, Gyeongsan-si, Gyeongsangbuk-do 712-749 (Korea, Republic of)
- Daegu Haany University, College of Oriental Medicine, Gyeongsan-si, Gyeongsangbuk-do 712-715 (Korea, Republic of)
Silver nanoparticles (nano-Ag) have been widely used in various commercial products including textiles, electronic appliances and biomedical products. However, there remains insufficient information on the potential risk of nano-Ag to human health and environment. In the current study, we have investigated the role of NF-E2-related factor 2 (Nrf2) transcription factor in nano-Ag-induced cytotoxicity. When Nrf2 expression was blocked using interring RNA expression in ovarian carcinoma cell line, nano-Ag treatment showed a substantial decrease in cell viability with concomitant increases in apoptosis and DNA damage compared to the control cells. Target gene analysis revealed that the expression of heme oxygenase-1 (HO-1) was highly elevated by nano-Ag in nonspecific shRNA expressing cells, while Nrf2 knockdown cells (NRF2i) did not increase HO-1 expression. The role of HO-1 in cytoprotection against nano-Ag was reinforced by results using pharmacological inducer of HO-1: cobalt protoporphyrin-mediated HO-1 activation in the NRF2i cells prevented nano-Ag-mediated cell death. Similarly, pharmacological or genetic inhibition of HO-1 in nonspecific control cells exacerbated nano-Ag toxicity. As the upstream signaling mechanism, nano-Ag required the phosphoinositide 3-kinase (PI3K) and p38MAPK signaling cascades for HO-1 induction. The treatment with either PI3K inhibitor or p38MAPK inhibitor suppressed HO-1 induction and intensified nano-Ag-induced cell death. Taken together, these results suggest that Nrf2-dependent HO-1 up-regulation plays a protective role in nano-Ag-induced DNA damage and consequent cell death. In addition, nano-Ag-mediated HO-1 induction is associated with the PI3K and p38MAPK signaling pathways. -- Highlights: ► Role of Nrf2 signaling in silver nanoparticle toxicity. ► Silver nanoparticle toxicity is increased by Nrf2 blockade. ► Nrf2-dependent HO-1 induction protects cells from silver nanoparticle toxicity. ► PI3K and p38MAPK cascades are involved in Nrf2/HO-1 induction.
- OSTI ID:
- 22215202
- Journal Information:
- Toxicology and Applied Pharmacology, Vol. 258, Issue 1; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0041-008X
- Country of Publication:
- United States
- Language:
- English
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