Insights into the impact of silver nanoparticles on human keratinocytes metabolism through NMR metabolomics

abstract

Due to their antimicrobial properties, silver nanoparticles (AgNPs) are increasingly incorporated into consumer goods and medical products. Their potential toxicity to human cells is however a major concern, and there is a need for improved understanding of their effects on cell metabolism and function. Here, Nuclear Magnetic Resonance (NMR) metabolomics was used to investigate the metabolic profile of human epidermis keratinocytes (HaCaT cell line) exposed for 48 h to 30 nm citrate-stabilized spherical AgNPs (10 and 40 p.g/mL). Intracellular aqueous extracts, organic extracts and extracellular culture medium were analysed to provide an integrated view of the cellular metabolic response. The specific metabolite variations, highlighted through multivariate analysis and confirmed by spectral integration, suggested that HaCaT cells exposed to AgNPs displayed upregulated glutathione-based antioxidant protection, increased glutaminolysis, downregulated tricarboxylic acid (TCA) cycle activity, energy depletion and cell membrane modification. Importantly, most metabolic changes were apparent in cells exposed to a concentration of AgNPs which did not affect cell viability at significant levels, thus underlying the sensitivity of NMR metabolomics to detect early biochemical events, even in the absence of a clear cytotoxic response. It can be concluded that NMR metabolomics is an important new tool in the field of in vitro nanotoxicology. (C) 2015 Elsevier Inc. All rights reserved.

keywords

IN-VITRO; SILICA NANOPARTICLES; CELL-CULTURE; LIPID RAFTS; TOXICITY; CYTOTOXICITY; NANOMATERIALS; H-1-NMR; LINE; SKIN

subject category

Biochemistry & Molecular Biology; Biophysics

authors

Carrola, J; Bastos, V; de Oliveira, JMPF; Oliveira, H; Santos, C; Gil, AM; Duarte, IF

Groups

G5 - Biomimetic, Biological and Living Materials

Projects

Metabolic profiling: a novel tool for evaluation of the toxicological and biological effects of nanomaterials (PTDC/SAU-TOX/120953/2010)

CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)

Rede Nacional de Ressonância Magnética Nuclear (PTNMR)

acknowledgements

This work was developed in the scope of the projects CICECO-Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2013) and CESAM (Ref. FCT UID/AMB/50017/2013), financed by National funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. Funding by the European Regional Development Fund (FEDER) through the Competitive Factors Thematic Operational Programme (COMPETE) and by National Funds through the Foundation for Science and Technology (FCT), under the project FCOMP-01-0124-FEDER-021456 (Ref. FCT PTDC/SAU-TOX/120953/2010) is acknowledged. The grants awarded by FCT to JC (SFRH/BD/79494/2011), VB (SFRH/BD/81792/2011), HO (SFRH/BPD/48853/2008) and JMPFO (SFRH/BPD/74868/2010) are also acknowledged. The authors are also grateful to Prof. Ruth Duncan for insightful discussions and helpful comments, and further acknowledge Dr Manfred Spraul, Bruker BioSpin (Germany), for access to software and spectral database, and the Portuguese National NMR (PTNMR) Network, supported with FCT funds.