A Novel Nontoxic Inhibitor of the Activation of NADPH Oxidase Reduces Reactive Oxygen Species Production in Mouse Lung

1-Hexadecyl-3-trifluoroethylglycero-sn-2-phosphomethanol (MJ33) is a fluorinated phospholipid analog that inhibits the phospholipase A(2) (PLA(2)) activity of peroxiredoxin 6 (Prdx6). Prdx6 PLA(2) activity is required for activation of NADPH oxidase 2 and subsequent generation of reactive oxygen species (ROS). In vitro, MJ33 inhibited agonist-stimulated production of ROS by the isolated perfused mouse lung, lung microvascular endothelial cells, and polymorphonuclear leukocytes. MJ33 (0.02-0.5 mu mol MJ33/kg body weight) in mixed unilamellar liposomes was administered to C57BL/6 mice by either intratracheal (i.t.) or i.v. routes. Lung MJ33 content, measured by liquid chromatography/mass spectroscopy, showed uptake of 67-87% of the injected dose for i.t. and 23-42% for i.v. administration at 4 hours postinjection. PLA(2) activity of lung homogenates was markedly inhibited (>85%) at 4 hours postadministration. Both MJ33 content and PLA(2) activity gradually returned to near control levels over the subsequent 24-72 hours. Mice treated with MJ33 at 12.5-25 mu mol/kg did not show changes (compared with control) in clinical symptomatology, body weight, hematocrit, and histology of lung, liver, and kidney during a 30- to 50-day observation period. Thus, the toxic dose of MJ33 was >25 mu mol/kg, whereas the PLA(2) inhibitory dose was approximately 0.02 mu mol/kg, indicating a high margin of safety. MJ33 administered to mice prior to lung isolation markedly reduced ROS production and tissue lipid and protein oxidation during ischemia followed by reperfusion. Thus, MJ33 could be useful as a therapeutic agent to prevent ROS-mediated tissue injury associated with lung inflammation or in harvested lungs prior to transplantation.