Proteomic analysis to identify markers of exposure to cadmium sulphide quantum dots (CdS QDs)

Abstract

Background The increasing use of cadmium sulphide (CdS) quantum dot (QD)-enabled products is expected to be accompanied by their release into the environment. In this study, the whole organism Saccharomyces cerevisiae was used as a model eukaryote to study protein modulations employing 2D- gel electrophoresis and gel-free iTRAQ (Isobaric Tags for Relative and Absolute Quantitation) proteomics following cell exposure to CdS QDs for 9 and 24 h. From both biotechnological and ecotoxicological perspectives, the use of S. cerevisiae as a model organism sheds light on the impact nanomaterials have on the biochemical responses of the exposed organism. Results Key proteins involved in essential biological pathways were downregulated, in particular after 24 h exposure. These include the major proteins of the glycolytic pathway, the components of mitochondrial respiratory chain complexes III, IV and V involved in the oxidative phosphorylation chain, the ATP-dependent molecular chaperone Hsc82 as well as other proteins responsible for protein folding and ubiquitination in the endoplasmic reticulum. Some of the proteins whose expression was altered have previously been described as strongly-adsorbed by CdS QD nanomaterial surfaces as hard corona, and involved in the cytotoxicity of this class of engineered nanomaterials. These data may be extrapolated to broader contexts and a wider range of organisms by allowing the identification of robust biomarkers of exposure to CdS QDs. Conclusions The work shows the power of the model organisms S. cerevisiae in biotechnology to ensure high levels of health and environmental safety. In fact, the double proteomic approach allowed to identify early markers of exposure to CdS QDs among all the proteins reprogrammed by the treatment.