THE NITRONE 5,5-DIMETHYL-1-PYRROLINE N-OXIDE REDUCES PULMONARY NEUTROPHILIC INFLAMMATION IN A MOUSE MODEL OF ACUTE LUNG INJURY CAUSED BY Pseudomonas aeruginosa

LOPEZ C M¹; MATTAR DOMÍNGUEZ M A; RAMÍREZ D C; GOMEZ MEJIBA S E¹

san luis

Congreso; SBC; 2024

032. THE NITRONE 5,5-DIMETHYL-1-PYRROLINE N-OXIDE REDUCES PULMONARY NEUTROPHILICINFLAMMATION IN A MOUSE MODEL OF ACUTE LUNG INJURY CAUSED BY Pseudomonas aeruginosaLopez C M¹, Mattar Domínguez M A2, Ramírez D C3, Gomez Mejiba S E¹¹ Laboratory of Nutrition and Experimental Therapeutics, IMIBIO-SL CONICET; 2Laboratory of Microbiology and Immunology, NationalUniversity of San Luis (UNSL); 3Laboratory of Experimental and Translational Medicine, IMIBIO-SL CONICET. San Luis, 5700 San Luis,Argentina. cristofermlopez.1@gmail.com sandraegomezmejiba@yahoo.comLipopolysaccharide (LPS), is a component of the outer membrane of Gram-negative bacteria, such as Pseudomonas aeruginosa (Pa) that causes redoxchanges and inflammatory NF-κB-controls gene expression. In the pulmonary microvasculature, the latest controls the expression of adhesionmolecules which can slow down neutrophil migration and further activation (a process known as pulmonary neutrophilic inflammation, PNI). DuringPNI, myeloperoxidase (MPO) is released and can be taken up by surrounding airway epithelial cells, where it can oxidize chloride anions to HOCl.HOCl is a powerful oxidant that can damage the genomic DNA by free radical-operated mechanisms. Herein we aimed to test in vivo whether thenitrone 5,5-dimethyl-1-pyrroline N-oxide (DMPO) can prevent DNA-centered radical formation in C57 male mice exposed to dead Pa. After 24 h oforopharyngeal aspiration of Pa (5x107 cells), we found a marked PNI, as assessed by a large infiltration of neutrophils, MPO (content and activity),and chlorotyrosine-modified proteins in the BALF and lung parenchyma. We also found increased expression of ICAM-1, inducible nitric oxidesynthase, and content of nitrotyrosine-modified proteins in the lung parenchyma, as well as increased pro-inflammatory cytokines in serum. Thesechanges were blocked when DMPO (2.5 μmol/mice) was administrated 1h before the exposure to Pa. DMPO also trapped protein and DNA radicalsin the lung parenchyma forming protein- and DNA-nitrone adducts (immuno-spin trapping technique). These data indicate that DMPO reduces Painducedgenotoxic and proteotoxic stress. Taken together, these data are consistent with an effect of DMPO interfering with the LPS-triggered signalingcausing inhibition of the expression of genes under the transcriptional control of NF-κB, thus blocking PNI. The nitrone spin trap can serve as a novelstructural platform for the design of novel drugs to reduce death associated with sepsis and genotoxic damage to the airways.