Network toxicology-driven insights on nitrogen-based flame retardant-induced hepatotoxicity: Computational prediction and experimental validation

Nitrogen-based flame retardants (NBFRs) are widely used in various products, and their long-term exposure may cause liver damage in humans. However, the underlying mechanism remains unclear. This study systematically investigated the mechanisms of NBFR-induced liver injury by integrating network toxicology, molecular docking, and Mendelian randomization analyses. The potential target genes of NBFR and liver injury-related genes were obtained from multiple databases. A protein-protein interaction network was constructed, followed by functional enrichment analysis. The core genes were validated using 2 liver injury-related transcriptomic datasets. Subsequently, molecular docking was performed to simulate the binding interactions between NBFR and the core proteins. Toxicological assessment revealed that NBFRs had significant hepatotoxic potential. The intersection analysis identified 41 genes related to both NBFR exposure and liver injury. Cross-validation using 2 transcriptomic datasets confirmed that superoxide dismutase 2 (SOD2) was a core target gene. Molecular docking results showed that all 4 NBFR compounds exhibited stable binding to SOD2. NBFR treatment significantly reduced telomerase-immortalized human liver epithelial-2 cell viability in a time-dependent manner, as determined by the Cell Counting Kit-8 assay. Moreover, quantitative polymerase chain reaction analysis revealed a marked downregulation of SOD2 mRNA levels, whereas western blot analysis confirmed a corresponding decrease in SOD2 protein expression. This study identified SOD2 as a key molecular target mediating liver injury induced by NBFR, although further experimental validation is required to confirm its mechanisms and clinical relevance.