Functional genomics and metabolomics reveal the toxicological effects of cadmium in Mus musculus mice

Abstract

Cadmium (Cd) is an environmental pollutant that accumulates in the organisms causing serious health problems. Over the past decades, omics studies have been conducted trying to elucidate changes in the genome, the transcriptome or the proteome after Cd exposure. Metabolomics is relatively new to the omics revolution, but has shown enormous potential for investigating biological systems or their perturbations. When metabolomic data are interpreted in combination with genomic, transcriptomic and proteomic results, in the so-called systems biology approach, a holistic knowledge of the organism/process under investigation can be achieved. In this work, transcriptional and proteomic analysis (functional genomics) were combined with metabolomic workflow to evaluate the biological responses caused in Mus musculus mice by Cd (subcutaneous injection for 10 consecutive days). Animals showed high Cd levels in liver and plasma, drastic lipid peroxidation in liver, increased transcription of hepatic genes involved in oxidative stress, metal transport, immune response and lipid metabolism and moderate decreases of DNA repair genes mRNAs. 2DE-DIGE proteomics confirmed changes of hepatic proteins related to stress and immune responses, or involved in energy metabolism, suggesting a metabolic switch in the liver from oxidative phosphorylation to aerobic glycolysis, that was confirmed by metabolomics analysis, via DIMS and GC–MS. This metabolic alteration is particularly important for highly proliferating cells, like tumor cells, which requires a continuous supply of precursors for the synthesis of lipids, proteins and nucleic acids. The metabolic changes observed in mouse liver by metabolomics and the oxidative stress detected via functional genomics could be in the base of Cd hepatocarcinogenicity.