An integrated LC-MS/MS platform for noninvasive urinary nucleus acid adductomics: A pilot study for tobacco exposure

Tobacco smoke exposure significantly increases the level of global nucleoside damage. To evaluate all aspects of nucleic acid (NA) modifications, NA adductomics analyzes DNA, RNA and nucleobase adducts and provides comprehensive data. Liquid chromatography-tandem triple quadrupole mass spectrometry (LC-QQQ-MS/MS) and LC-Zeno-TOF-MS/MS were employed to screen for DNA, RNA and nucleobase adducts, as part of the analytical platform that was designed to combine high sensitivity and high resolution detection. We identified and distinguished urine nucleoside adducts via precursor ion and neutral loss scanning. A total of 245 potential adducts were detected, of which 28 were known adducts. The smoking group had significantly higher concentrations of nucleoside adducts in rat urine than the control group, based on MRM scanning, which was then used to perform relative quantitative analysis of these adducts. Urine nucleoside adducts were further confirmed using LC-Zeno-TOF-MS/MS. This highlights the potential of untargeted detection methods to provide comprehensive data on both known and unknown adducts. These approaches can be used to investigate the interactions among oxidative and alkylation stresses, and epigenetic modifications caused by exposure to tobacco smoke. Tobacco smoke is a common environmental pollutant, and many of its chemicals have been identified as hazardous substances. Oxidants and carcinogens in tobacco smoke trigger oxidative and alkylation stress, causing nucleoside damage in humans. This research aimed to establish a highly sensitive platform to construct a global nucleotide adduct profile of DNA, RNA, and nucleobase adducts in urine, expanding the existing urinary nucleoside adductome. Our findings revealed a significant increase in urine nucleoside adduct levels in the tobacco smoke exposure group, highlighting the potential negative role of tobacco smoking exposure on oxidative and alkylation pressure and epigenetic effects.