Proteomic responses of human intestinal Caco-2 cells exposed to silver nanoparticles and ionic silver

• Published in: Journal of applied toxicology 2016-03, Vol.36 (3), p.404-413
• Main Authors: Oberemm, Axel, Hansen, Ulf, Böhmert, Linda, Meckert, Christine, Braeuning, Albert, Thünemann, Andreas F., Lampen, Alfonso
• Format: Article
• Language: English
• Subjects: 2-DE; Caco-2 Cells; Cell Survival - drug effects; Cytotoxicity; Deregulation; Dose-Response Relationship, Drug; Electrophoresis, Gel, Two-Dimensional; Exposure; hazard identification; Humans; in vitro; Intestinal Mucosa - drug effects; Intestinal Mucosa - metabolism; Intestinal Mucosa - pathology; MALDI-TOF MS; Metal Nanoparticles - chemistry; Nanoparticles; Nanostructure; Protein folding; Proteins; Proteins - metabolism; Proteomics; Proteomics - methods; Silver; Silver - chemistry; Silver - pharmacology; silver nanoparticles; Silver Nitrate - chemistry; Silver Nitrate - pharmacology; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Spots; Tandem Mass Spectrometry; Time Factors; two-dimensional gel electrophoresis
• ISSN: 0260-437X; 1099-1263
• DOI: 10.1002/jat.3231

Even although quite a number of studies have been performed so far to demonstrate nanoparticle‐specific effects of substances in living systems, clear evidence of these effects is still under debate. The present study was designed as a comparative proteomic analysis of human intestinal cells exposed to a commercial silver nanoparticle reference material and ions from AgNO3. A two‐dimensional gel electrophoresis/MALDI mass spectrometry (MS)‐based proteomic analysis was conducted after 24‐h incubation of differentiated Caco‐2 cells with non‐cytotoxic and low cytotoxic silver concentrations (2.5 and 25 µg ml−1 nanosilver, 0.5 and 5 µg ml−1 AgNO3). Out of an overall number of 316 protein spots differentially expressed at a fold change of ≥ 1.4 or ≤ −1.4 in all treatments, 169 proteins could be identified. In total, 231 spots were specifically deregulated in particle‐treated groups compared with 41 spots, which were limited to AgNO3‐treatments. Forty‐four spots (14 %) were commonly deregulated by both types of treatment. A considerable fraction of the proteins differentially expressed after treatment with nanoparticles is related to protein folding, synthesis or modification of proteins as well as cellular assembly and organization. Overlays of networks obtained for particulate and ionic treatments showed matches, indicating common mechanisms of combined particle and ionic silver exposure and exclusive ionic silver treatment. However, proteomic responses of Caco‐2 cells treated with higher concentrations of silver species also showed some differences, for example regarding proteins related to fatty acid and energy metabolism, suggesting an induction of also some different molecular mechanisms for particle exposure and ionic treatment. Copyright © 2015 John Wiley & Sons, Ltd. This study showed that exposure to non‐toxic amounts of nanosized and ionic silver induced different patterns of deregulated proteins in human Caco‐2 cells. Much more proteins were differentially expressed after exposure to nanosilver compared with ionic treatments and only a relatively small proportion of protein spots were commonly deregulated by both, particle and ionic treatments. However, overlays of functional networks obtained for particulate and ionic treatments revealed overlaps, indicating some common cellular mechanisms.