Omics

Untargeted omic analyses in general are conducted in subjects for whom the external exposome has been measured and, where possible, all omic platforms are used in the same subjects to enable cross-omic analyses.

Metabolomics (MS technology)

Plasma or serum samples have been analysed by high resolution mass spectrometry (MS) coupled to UPLC. Metabolic features characterizing exposed groups are identified by multivariate statistics with appropriate correction for the False Discovery Rate (FDR), and efforts to identify the discriminating metabolites are made. A database of known biomarkers from the main environmental contaminants in air and water as measured in various populations has been compiled from the scientific literature into the Exposome-Explorer database (http://exposome-explorer.iarc.fr/).

Adductomics

Application of adductomics to the exposome concept involves an untargeted investigation of the internal exposome based on the measurement of complete categories of features (e.g. protein adducts). The untargeted approach has been realised by focusing on a specific locus of HSA, and using MS of hydrolysis products to profile covalent modifications over a range of masses.

Intermediate omic biomarkers

Additional omic technologies for the analysis of biological molecules have been used to measure the more downstream effects of environmental exposures. These include the effect on the transcriptome, the epigenome and the proteome. Measurements have been conducted using:

1. Transcriptomics (Agilent platform) (number of signals per sample: 44k)

2. Epigenomics:

• Global DNA methylation (Illumina platform) (number of signals per sample: 450k
• microRNA analysis (Agilent platform) (number of signals per sample>1,000)

3. Targeted proteomics (Luminex Multianalyte Profiling platform for inflammation-related proteins) (number of signals per sample ~30).