MJ33, an inhibitor of the phospholipase A2 activity of peroxiredoxin 6, reduces reactive oxygen species production in a model of endotoxin induced lung inflammation

Abstract

NADPH oxidases (NOX) are a major source of enzymatically generated reactive oxygen species (ROS) in mammalian cells; of these, Nox2 activation is thought to play a role in the injury associated with lung inflammation. We reported that Nox2 activation and ROS production occurs through peroxiredoxin 6 (Prdx6) and its subsequent PLA2 activity. Thus blocking Prdx6 PLA2 activity can be a strategy to inhibit ROS generation during inflammation. Here we used MJ33, a potent Prdx6 PLA2 inhibitor and evaluated ROS generation in endothelial cells in vitro and in mouse lungs in vivo post LPS treatment. LPS was either added to endothelial cells in culture or injected i.v. or i.t in mice, while MJ33 was added directly to cell cultures or administered i.t. at doses between 1–10 mole % in liposomes. ROS generation in endothelial cells (monitored by H2DCF fluorescence) showed a 3‐ fold increase after LPS treatment as compared to controls; however addition of MJ33 reduced ROS levels to control values. Lungs from mice treated with LPS showed an almost 10 fold higher rate of ROS production (as monitored by H2O2 specific dye, amplex red) which was abolished by pretreatment with MJ33. Administration of MJ33 in LPS treated mice reduced ROS levels to values as seen with Prdx6 null and Nox2 null lungs indicating that Prdx6 PLA2 activity is critical to LPS induced ROS production and that MJ33 treatment may provide a favorable outcome during inflammation.