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

Abstract

Besides cell death, nanoparticles (Nps) can induce other cellular responses such as inflammation. The potential immune response mediated by the exposure of human lymphoid cells to metal oxide Nps (moNps) was characterized using four different moNps (CeO₂, TiO₂, Al₂O₃, and ZnO) to study the three most relevant mitogen-activated protein kinase subfamilies and the nuclear factor kappa-light-chain-enhancer of the activated B-cell inhibitor, IκBα, as well as the expression of several genes by immune cells incubated with these Nps. The moNps activated different signaling pathways and altered the gene expression in human lymphocyte cells. The ZnO Nps were the most active and the release of Zn²⁺ ions was the main mechanism of toxicity. CeO₂ Nps induced the smallest changes in gene expression and in the IκBα protein. The effects of the particles were strongly dependent on the type and concentration of the Nps and on the cell activation status prior to Np exposure.

Keywords:

• Jurkat
• MAPK
• NFκB
• qPCR
• inflammation
• metabolism

Supplementary materials

Nanoparticles were analyzed by transmission electron microscopy and DLS in different media (Figure S1).

The Western blot images quantified in Figure 1 (Figure S2), cells incubated with a tenfold lower Np concentration (Figure S3) or with three different concentrations of Zn²⁺ ions (Figure S4) are shown.

Figure S1 TEM images of uncoated CeO₂, TiO₂, Al₂O₃, and ZnO Nps in water (A–D). DLS measurements of the four Nps in water (E) and in PBS pH 7.4 or with albumin at 400 μg/mL prepared in PBS (F).

Notes: The diameter of the Np aggregates, determined by intensity distribution, and the PdI are represented. Standard deviation is shown in error bars (n=4). Reprinted from Colloids Surf B Biointerfaces, 113, Simón-Vázquez R, Lozano-Fernández T, Peleteiro-Olmedo M, González-Fernández Á, Conformational changes in human plasma proteins induced by metal oxide nanoparticles, 198–206, Copyright 2016, with permission from Elsevier.¹

Abbreviations: DLS, dynamic light scattering; Nps, nanoparticles; PBS, phosphate-buffered saline; PdI, polydispersity index; TEM, transmission electron microscopy.

Figure S2 Western blot showing the expression of p-ERK (1,2), p-p38, p-SAPK/JNK, and IκBα in Jurkat cells, either untreated (control cells, C) or treated with 100 μg/mL CeO₂, TiO₂, Al₂O₃, and 50 μg/mL ZnO Nps.

Note: Cells were prestimulated (+PHA) or not (−PHA) with PHA.

Abbreviations: ERK, extracellular signal-regulated kinase; h, hour; IκBα, nuclear factor kappa-light-chain-enhancer of the activated B-cell inhibitor; JNK, c-Jun amino-terminal kinase; Nps, nanoparticles; PHA, phytohemagglutinin; SAPK, stress-activated protein kinase.

Figure S3 Activation of ERK (1,2), p38, SAPK/JNK, and degradation of IκBα, the NFκB inhibitor, in Jurkat cells in the presence of CeO₂, TiO₂, Al₂O₃, and ZnO nanoparticles.

Notes: Jurkat cells, prestimulated (+PHA) or not (−PHA) with PHA, were incubated with CeO₂, TiO₂, or Al₂O₃ Nps (all at 10 μg/mL) and ZnO Nps (at 5 μg/mL) at two different times (1 and 3 hours). GAPDH was used as a loading control (indicated by arrows).

Abbreviations: ERK, extracellular signal-regulated kinase; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; h, hour; IκBα, NFκB inhibitor; JNK, c-Jun amino-terminal kinase; NFκB, nuclear factor kappa-light-chain-enhancer of the activated B-cell; Nps, nanoparticles; PHA, phytohemagluttinin; SAPK, stress-activated protein kinase.

Figure S4 Activation of ERK (1,2), p38, SAPK/JNK, and IκBα induced by the Zn²⁺ ions in Jurkat cells.

Note: The Zn²⁺ ions were tested at three different concentrations (1, 10, and 100 μg/mL), and in the presence of absence of PHA.

Abbreviations: ERK, extracellular signal-regulated kinase; h, hour; IκBα, nuclear factor kappa-light-chain-enhancer of the activated B-cell inhibitor; JNK, c-Jun amino-terminal kinase; Nps, nanoparticles; PHA, phytohemagluttinin; SAPK, stress-activated protein kinase.

Reference

• Simón-VázquezRLozano-FernándezTPeleteiro-OlmedoMGonzález-FernándezÁConformational changes in human plasma proteins induced by metal oxide nanoparticlesColloids Surf B Biointerfaces201411319820624095988
   PubMed Web of Science ®Google Scholar

Acknowledgments

We would like to thank Sergio Moya and Plasmachem for providing the nanomaterials. We also thank Andrea Hernández-Fernández for excellent technical support, Dr Ángel S. Comesaña for the technical qPCR services at the Centro de Apoyo Científico-Tecnológico a la Investigación, and Dr Luiz Stark for reading the manuscript and for his helpful comments. This work was supported by the Health Impact of Engineered Metal and Metal Oxide Nanoparticles: Response, Bioimaging and Distribution at Cellular and Body Level project (228825, FP7-NMP-SMALL-2) and the Xunta de Galicia (INBIOMED 2012/273, DXPCTSUG-FEDER, Grupo de Potencial de Crecimiento GPC2013-005). We also thank the BIOCAPS project (316265, FP7/REGPOT-2012-2013.1) and acknowledge an Formación de Profesorado Universitario fellowship from the Spanish Ministry of Education to TLF.

Disclosure

The authors report no conflicts of interest in this work.