Toxicogenomics

Toxicogenomics is an interdisciplinary field that combines toxicology with genomics to study how biological systems respond at the molecular level to chemical exposure. It uses genome-scale data to investigate the mechanisms of toxicity, individual susceptibility, and dose–response relationships.

Methods rely on high-throughput technologies: transcriptomics (microarrays, RNA-seq), proteomics, and metabolomics, typically in cell lines, tissues, or whole organisms. Experimental designs include exposure to chemicals or drugs, followed by collection of samples for omics profiling. Data analysis involves differential expression, pathway and network analyses, and integration with toxicology endpoints. Public repositories and toxicogenomic databases provide reference signatures and benchmarks. The concept of adverse outcome pathways (AOPs) is often used to link molecular initiating events to higher-level adverse effects.

Applications include hazard identification and mechanism elucidation, biomarker discovery for exposure and effect, and informing regulatory risk assessment. Toxicogenomics can contribute to alternative testing strategies by identifying in vitro signatures that predict in vivo outcomes and by prioritizing chemicals for further testing.

Challenges include data heterogeneity, reproducibility, and cross-species extrapolation, as well as the need for standardized protocols and robust validation of putative biomarkers. The field is evolving toward systems toxicology, integrating multi-omics data to model complex toxic responses and to support more efficient and ethical regulatory decision making.