Genotoxic effects of neutrophils and hypochlorous acid.
Chronic inflammation has been recognized as a contributing factor in the pathogenesis of lung cancer. In this process, reactive oxygen species released by neutrophils may play an important role. The aim of the present study was to investigate the capacity of the major neutrophilic oxidant hypochlorous acid (HOCl), which is formed by myeloperoxidase (MPO), to induce DNA damage and mutagenicity in lung cells. HOCl was mutagenic in lung epithelial A549 cells in vitro, showing at physiological concentrations a significant induction of mutations in the HPRT gene. We studied three major types of DNA lesions that could be relevant for this HOCl-induced mutagenicity. Single strand DNA breakage and 8-oxo-7,8-dihydro-2'-deoxyguanosine were not found to be increased following HOCl treatment. On the other hand, HOCl caused a significant increase in the formation of 3-(2-deoxy-beta-D-erythro-pentofuranosyl)pyrimido[1,2-alpha]purin-10(3H)-one (M(1)dG), which can be formed by either malondialdehyde (MDA) or base propenals. We observed an increased MDA formation upon exposure of A549 cells to HOCl, but a role of base propenals cannot be excluded. In line with this, we observed 4-fold increased M(1)dG adduct levels in mice that were intratracheally instilled with lipopolysaccharide to induce a pulmonary inflammation with neutrophil influx. Depletion of circulating neutrophils significantly reduced pulmonary MPO activity as well as M(1)dG adducts levels, thereby providing a causal link between neutrophils/HOCl and pulmonary genotoxicity in vivo. Taken together, these data indicate that MPO catalysed formation of HOCl during lung inflammation should be considered as a significant source of neutrophil-induced genotoxicity.
Güngör
Nejla
N
Department of Health Risk Analysis and Toxicology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, PO Box 616, 6200 MD, Maastricht, The Netherlands.
Knaapen
Ad M
AM
Munnia
Armelle
A
Peluso
Marco
M
Haenen
Guido R
GR
Chiu
Roland K
RK
Godschalk
Roger W L
RW
van Schooten
Frederik J
FJ
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000236:Adenoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D018736:DNA Adducts; D053904:DNA Breaks, Single-Stranded / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects*; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D006997:Hypochlorous Acid / Q000633:toxicity*; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics / Q000378:metabolism; D007249:Inflammation / Q000139:chemically induced; D015227:Lipid Peroxidation / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D008175:Lung Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation / Q000235:genetics; D009504:Neutrophils / Q000378:metabolism*; D016877:Oxidants / Q000633:toxicity*; D009195:Peroxidase / Q000378:metabolism; D011684:Purine Nucleosides / Q000378:metabolism
C491625:3-(2'-deoxy-beta-D-erythro-pentofuranosyl)pyrimido(1,2-alpha)purin-10(3H)-one; D018736:DNA Adducts; D008070:Lipopolysaccharides; D016877:Oxidants; D011684:Purine Nucleosides; D008315:Malondialdehyde; D006997:Hypochlorous Acid; D000080242:8-Hydroxy-2'-Deoxyguanosine; D009195:Peroxidase; D007041:Hypoxanthine Phosphoribosyltransferase; D003849:Deoxyguanosine