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Investigating Oxidative Stress and Inflammatory Responses Elicited by Silver Nanoparticles Using High-Throughput Reporter Genes in HepG2 Cells: Effect of Size, Surface Coating, and Intracellular Uptake
Prasad, R., J. McGee, M. Killius, D. Ackerman, C. Blackman, D. DeMarini, AND Steve Simmons. Investigating Oxidative Stress and Inflammatory Responses Elicited by Silver Nanoparticles Using High-Throughput Reporter Genes in HepG2 Cells: Effect of Size, Surface Coating, and Intracellular Uptake. TOXICOLOGY IN VITRO. Elsevier Science Ltd, New York, NY, 27(6):2013-21, (2013).
Abstract Silver nanoparticles (Ag NP) have been shown to generate reactive oxygen species; however, the association between physicochemical characteristics of nanoparticles and cellular stress responses elicited by exposure has not been elucidated. Here, we examined three key stress-responsive pathways activated by Nrf-2/ARE, NFκB, and AP1 during exposure to Ag NP of two distinct sizes (10 and 75 nm) and coatings (citrate and polyvinylpyrrolidone), as well as silver nitrate (AgNO3), and CeO2 nanoparticles. The in vitro assays assessed the cellular response in a battery of stable luciferase-reporter HepG2 cell lines. We further assessed the impact of Ag NP and AgNO3 exposure on cellular redox status by measuring glutathione depletion. Lastly, we determined intracellular Ag concentration by inductively coupled plasma mass spectroscopy (ICP-MS) and re-analyzed reporter-gene data using these values to estimate the relative potencies of the Ag NPs and AgNO3. Our results show activation of all three stress response pathways, with Nrf-2/ARE displaying the strongest response elicited by each Ag NP and AgNO3 evaluated here. The smaller (10-nm) Ag NPs were more potent than the larger (75-nm) Ag NPs in each stress-response pathway, and citrate-coated Ag NPs had higher intracellular silver concentrations compared with both PVP-coated Ag NP and AgNO3. The cellular stress response profiles after Ag NP exposure were similar to that of AgNO3, suggesting that the oxidative stress and inflammatory effects of Ag NP are likely due to the cytotoxicity of silver ions. Disclaimer: The information in this document has been funded wholly (or in part) by the U.S. Environmental Protection Agency. It has been subjected to review by the National Health and Environmental Effects Research Laboratory and approved for publication. Approval does not signify that the contents reflect the views of the Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.
This study was done in order to characterize the bioactivity and potential toxicity of silver nanoparticles. Silver nanoparticles are increasing used in a variety of commercial applications such as textiles, wound dressings, and appliances due to their antimicrobial properties. Their increased use necessitates a thoughtful characterization of any potential toxic effects. This is part of EPA’s ORD ongoing effort to characterize the biological properties of engineered nanoparticles.
Record Details:Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB
INTEGRATED SYSTEMS TOXICOLOGY DIVISION
GENETIC AND CELLULAR TOXICOLOGY BRANCH