Radiation-induced reactive oxygen species partially assemble neutrophil NADPH oxidase

• Published in: Free radical biology & medicine Vol. 164; pp. 76 - 84
• Main Authors: Owusu, Stephenson B., Hudik, Elodie, Férard, Céline, Dupré-Crochet, Sophie, Addison, Eric C.D.K., Preko, Kwasi, Bizouarn, Tania, Houée-Levin, Chantal, Baciou, Laura
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 20-02-2021; Elsevier
• Subjects: Humans; Hydrogen Peroxide; Immunology; Innate immunity; Ionizing radiation; Life Sciences; NADPH oxidase; NADPH Oxidases - genetics; Neutrophils; Phosphoproteins; Radiation; Reactive Oxygen Species; ROS; Superoxide radical; Superoxides; BCA; PMA; Neutrophils; cytb558; TBST; SOD; PKC; Superoxide radical; DDM; MAPK; TNF; ECL; Ionizing radiation; GM-CSF; PMSF; NADPH oxidase; ROS; AMPK; DPI; CAPS
• ISSN: 0891-5849; 1873-4596
• DOI: 10.1016/j.freeradbiomed.2020.12.233

Neutrophils are key cells from the innate immune system that destroy invading bacteria or viruses, thanks mainly to the non-mitochondrial reactive oxygen species (ROS) generated by the enzyme NADPH oxidase. Our aim was to study the response of neutrophils to situations of oxidative stress with emphasis on the impact on the NADPH oxidase complex. To mimic oxidative stress, we used gamma irradiation that generated ROS (OH•, O2•- and H2O2) in a quantitative controlled manner. We showed that, although irradiation induces shorter half-lives of neutrophil (reduced by at least a factor of 2), it triggers a pre-activation of surviving neutrophils. This is detectable by the production of a small but significant amount of superoxide anions, proportional to the dose (about 3 times that of sham). Investigations at the molecular level showed that this ROS increase was generated by the NADPH oxidase enzyme after neutrophils irradiation. The NADPH oxidase complex undergoes an incomplete assembly which includes p47phox and p67phox but excludes the G-protein Rac. Importantly, this irradiation-induced pre-activation is capable of considerably improving neutrophil reactivity. Indeed, we have observed that this leads to an increase in the production of ROS and the capacity of phagocytosis, leading to the conclusion that radiation induced ROS clearly behave as neutrophil primers.
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•Gamma irradiation, mimicking oxidative stress, triggers neutrophil priming.•Irradiated neutrophils generate moderate amount of ROS through the activation of NADPH oxidase.•ROS production is due to incomplete assembly of the NADPH oxidase complex at the plasma membrane of irradiated neutrophils.•A priming marker was identified on p47 (phosphorylation of Ser345).•Pre-stimulated neutrophils by irradiation respond with increased oxidative burst.