Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach

Abstract

Two different zinc oxide nanoparticles, as well as zinc ion, are used to study the cellular responses of the RAW264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are crossvalidated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations.3

Molecular responses of alveolar epithelial A549 cells to chronic exposure to titanium dioxide nanoparticles: A proteomic view

“…The median coefficient of variation of spot intensity was 21%; it ranged between 13% and 25% depending on the sample i.e. within the range of typical 2D gel-based experiments [22,37,38].…”

“…Sample preparation, 2D gel analysis and mass spectrometry were performed as already described [22]. Only the specific methods are described here.…”

A combined proteomic and targeted analysis unravels new toxic mechanisms for zinc oxide nanoparticles in macrophages

“…Despite their relatively scarce use, all proteomic studies have shown a potential to unravel interesting cellular responses, e.g. mitochondrial responses [25,27], cytoskeletal responses [26], or metabolic ones [28], metabolic responses being also demonstrated by targeted studies [29]. This is why, in addition to our previous work [28,30] carried out in RPMI, a medium that does not stimulate the AHR [20], we have undertaken a proteomic study of the responses of macrophages to zinc oxide nanoparticles in AHRstimulating conditions, i.e.…”

Metal oxide nanoparticles interact with immune cells and activate different cellular responses

“…7 However, the cellular and molecular effects of many moNps have not been fully characterized, although some effects on cell death, genotoxicity, and the production of reactive oxygen species by them have been described. [8][9][10][11] There has been a steady increase in the number of studies concerning gene expression and proteomic analysis, [12][13][14][15] but more investigations are urgently needed, especially those involving a comparison of the effects induced by different Nps on immune cells and aimed at understanding the cellular pathways that are activated by these NMs.…”

“…40 Moreover, the CYP19A1 gene involved in xenobiotic metabolism is upregulated in the presence of ZnO Nps. Indeed, ZnO Nps and Zn 2+ ions have a negative effect on macrophage metabolism 12 and they have also been shown to increase the amounts of some enzymes involved in glycolysis and in the pentose phosphate pathway, for example, 6-phosphogluconate dehydrogenase or aldose reductase.…”