Abstract

A metallomic analytical approach based on the use of size exclusion chromatography (Superdex-75 and Superdex TM-Peptide) coupled to ICP-MS has been used to obtain metal profiles related to metallobiomolecules overexpression or inhibition in mice caused by contamination. The method is complemented with a second chromatographic dimension (anion and cation exchange chromatography) for species purification and isolation, and in some cases metal-species identification by mass spectrometry. The biological response of free-living mice Mus spretus (liver, kidney and brain) from contaminated and non-contaminated areas of areas of Doñana National Park (southwest Spain) and the surroundings were found to be affected by differential contamination. The results reveal the presence of high concentration of Fe, Cu and Zn in liver and As and Cd in kidney in contaminated areas. Upregulation of peaks traced by Cu, Zn and Cd at 7 kDa (matching with metallothionein I standard) in liver cytosolic extract is triggered by the presence of contaminants. Other Cu and Zn-peaks located at 32 kDa are also overexpressed by pollution and can be related to upregulation of superoxide dismutase. In kidney the presence of Cu, Zn and Cd-binding peaks located at 7 kDa from sites affected by contamination can also be observed. Finally, the abundance of low molecular mass As species in kidney due to the excretion of this element as methyl and dimethylarsenic is remarkable. In addition, the laboratory mice Mus musculus was used as control due to already sequenced and genetically homologous to Mus spretus. For this reason, biological response of Mus musculus to metal contamination was checked by exposure experiments to Cd and As and results were compared with those obtained from Mus spretus from contaminated areas.

Keywords: Metallomics, SEC-ICP-MS, Mus spretus, Mus musculus, environmental metallomics, biological response, contamination