RNA-binding proteins are a major target of silica nanoparticles in cell extracts

Abstract

Upon contact with biological fluids, nanoparticles (NPs) are readily coated by cellular compounds, particularly proteins, which are determining factors for the localization and toxicity of NPs in the organism. Here, we improved a methodological approach to identify proteins that adsorb on silica NPs with high affinity. Using large-scale proteomics and mixtures of soluble proteins prepared either from yeast cells or from alveolar human cells, we observed that proteins with large unstructured region(s) are more prone to bind on silica NPs. These disordered regions provide flexibility to proteins, a property that promotes their adsorption. The statistical analyses also pointed to a marked overrepresentation of RNA-binding proteins (RBPs) and of translation initiation factors among the adsorbed proteins. We propose that silica surfaces, which are mainly composed of Si–O⁻ and Si–OH groups, mimic ribose-phosphate molecules (rich in –O⁻ and –OH) and trap the proteins able to interact with ribose-phosphate containing molecules. Finally, using an in vitro assay, we showed that the sequestration of translation initiation factors by silica NPs results in an inhibition of the in vitro translational activity. This result demonstrates that characterizing the protein corona of various NPs would be a relevant approach to predict their potential toxicological effects.

• Protein corona
• proteomics
• silica nanoparticles
• intrinsically disordered protein
• RNA binding protein

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

This work was supported under grant “program de toxicologie” by Atomic Energy and Alternative Energies Commission (CEA); Christelle Mathé under grant “program NanoSciences Ile-de-France by C’nano IdF”; and Mathilde Biola-Clier and Marie Carrière under grant Labex Serenade (n° ANR-11-LABX-0064) funded by the “Investissements d’Avenir” French Government program of the French National Research Agency (ANR) through the A*MIDEX project (n° ANR-11-IDEX-0001-02).

Supplementary material available online