DMPO traps DNA-centered Radicals Preventing hrpt Gene Mutagenesis: a Model of Genotoxicity Induced at Sites of Neutrophilic Inflammation

RAMIREZ DARIO; LOPEZ CM; CLAVELES CASAS, FN; BARRERA FS; DI SCIULLO, MARÍA PAULA; GOMEZ-MEJIBA SANDRA

Las Vegas

Congreso; The Society for Redox Biology and Medicine´s 26th Annual Conference; 2019

The Society for Redox Biology and Medicine

Pulmonary neutrophilic inflammation is an acute response to airway irritation and includes recruitment and activation of neutrophils with the production of HOCL-a highly reactive species. HOCL produced hy myeloperoxidase (MPO) generates radical events in the genomic DNA. Co-incubation of lung epithelial cells with activated human neutrophils results in accumulation of MPO inside the epithelial cells a system that resembles neutrophilic inflammation in the irritated airways. Herein we sought to test whether DNA radicalization produced by intracellularly produced HOCL can cause hypoxanthine-guanine phosphoribosyltransferase (hrpt)- gene mutation in A549 airway epithelial cells and how the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) can modulate this process. Exposure of A549 cells loaded with active MPO and exposed to a flow or bolus addition of H2O2, produced HOCl inside them. Intracellularly produced HOCl caused DNA radicalization, 8-oxo-7,8-dihydro-2´-deoxyguanosine (8-oxo-dGuo), p53 translocation within the nucleus and hrpt gene mutation. DNA radicalization precedes 8-oxo-dGuo formation and hrpt gene mutation. The DMPO trapped DNA-centered radicals, reduced 8-oxo-dGuo accumulation, and blocked hrpt gene mutation. The mechanism and potential use of DMPO, or its structural derivatives, to reduce the accumulation of mutations at sites of neutrophilic inflammation is discussed. Supported by PICT3369/PIP916/PROICO 100218 and 023418/PUE IMIBIO-SL.