Analysis of genomic damage in the lung esposed to endotoxin using immuno-spin trapping

DARIO C. RAMIREZ; SANDRA E. GOMEZ-MEJIBA

CHASCOMUS

Congreso; SAB; 2013

SOCIEDAD ARGENTINA DE BIOLOGIA

Analysis of genoMIC damage in the lung exposed to endotoxin: Mechanisms and therapIES Ramirez DC1,2, Gomez-Mejiba SE1,3 1Laboratory of Experimental Medicine and Therapeutics-IMIBIO-SL-CONICET, 2FQByF and 3FCS, UNSL. 5700 San Luis, Argentin. E-mail:  ramirezlabimibiosl@ymail.com   To measure DNA radicalization we use the immuno-spin trapping assay with the nitrone spin trap 5,5-dimethyl-1-pyrroline ?N oxide (DMPO). Biochemical models showed that HOCl added as a bolus or continuously generated by myeloperoxidase (MPO) radicalizes purified DNA. Cell models showed that activated neutrophils can release MPO and epithelial cells can take it up. MPO inside epithelial cells exposed to H2O2 and in activated neutrophils can produce HOCl that radicalize genomic DNA. In addition, by trapping DNA radicals downstream effects, such as formation of 8-oxo-dG and mutation of the HPRT gene were prevented. Biochemical and cell models also showed that resveratrol crosses easily cell membranes and reacts faster with HOCl than with DNA and, thus protects against genotoxicity. In vivo models in mice shown that DMPO had a protective effect against neutrophilic inflammation triggered by intratracheal instillation of LPS. This protection was more likely due to interference with the retention of neutrophils caused by irritation of the airways by LPS. Indeed, DMPO interferes with the NF-kB signaling pathway triggered by LPS, thus decreased expression of adhesion molecules and pro-inflammatiory cytokines. Homing/activation of neutrophils, intracellular HOCl production and DNA radicalization are possible therapeutic targets against genotoxicity casued by neutrophilic inflammation of the airways.