Trapping DNA-centered Radicals Prevents Genotoxicity: an in vitro model

BARRERA, FLORENCIA; GOMEZ-MEJIBA, SANDRA; LOPEZ, CRISTOFER MARTÍN; DI SCIULLO, MARIA; CASAS, FLORENCIA CLAVELES; RAMIREZ, DARIO

FREE RADICAL BIOLOGY AND MEDICINE

ELSEVIER SCIENCE INC

Año: 2020 vol. 159 p. 44 - 45

0891-5849

Introduction: Neutrophilic inflammation (NI) is a tissue response to irritation that can lead to mutations. NI involves neutrophil activation at irritated sites where myeloperoxidase (MPO) is released and taken up by surrounding cells. Inside cells, and in the presence of H2O2, HOCl is formed, but whether it can cause genotoxicity is partially known. Objective: Herein we aimed at showing whether intracellularly produced HOCl can cause mutation in airway epithelial cells using an in vitro model. Method: Human A549 lung epithelial cells were either incubated with highly purifiedhuman MPO and then exposed to H2O2, or they were cocultured with a phorbol ester-activated human neutrophils. Results: Added or neutrophil released MPO was taken up by A549 cells. When exposed to H2O2 added as a bolus or generated by the glucose/glucose oxidase system, HOCl was intracellularly produced causing 8-oxo-dG formation, fosfo-p53 translocation into de nucleus, and mutation of the hypoxanthine phosphorybosyl transferase gene. These effects were prevented when cells where incubated with either a cell permeable MPO inhibitor (ABAH), a scavenger of HOCl (resveratrol) or when the nitrone spin trap 5,5-dimethyl-1-pyrrline N-oxide was added before H2O2 addition. Conclusion: These data suggest that DNA-radicalization caused by HOCl precedes 8-oxo-dG formation and mutagenesis