PULMONARY NEUTROPHILIC INFLAMMATION CAUSES MUTATIONS IN GENOMIC DNA

LOPEZ CM¹, ,¹ ; RAMÍREZ DC²; GOMEZ-MEJIBA SE

MAR DEL PLATA

Congreso; SAIC; 2023

Pulmonary neutrophilic inflammation (PNI) is caused by the homing and activation of neutrophils in the lung microvasculature exposed to environmental irritants. Upon activation, neutrophils release myeloperoxidase (MPO), the only enzyme that can, under physiological pH, use H2O2 to oxidize chloride ions to hypochlorous acid (HOCl).Released MPO can be taken up by surrounding lung epithelial cells, where it can produce HOCl. Genomic DNA oxidation by intracellularly produced HOCl can lead to mutagenesis and further cell transformation. The hypoxanthine phosphoribosyl transferase (hprt) gene is one of the most sensitive genes to oxidative mutagenesis. Thehrpt mutated cells survive in the presence of 6-thioguanine (6-TG). Herein we used an in vitro experimental model to test whether intracellularly produced HOCl can damage the genome, and whether the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) can protect the genome. To accomplish our aim we used human lungepithelial cells (A549 cell line) and incubate them to human MPO or human neutrophils activated with a phorbol ester (PMA) a well-characterized model of PNI. After these incubations, MPO was traced inside A549 epithelial cells very close to the cell nuclei (Confocal). Upon exposure of MPO-loaded A549 cells to H2O2 , HOCl was intracellularly generated (luminol assay), 8-oxo-deoxyguanosine (8-oxodG) was formed (ELISA in isolated DNA), and 6-TG-resistant cells136 MEDICINA - Volumen 83 - (Supl. V), 2023 1. DRAFT with HOMA-IR (p