Peroxiredoxin 6 is required for activation of NADPH oxidase (NOX2) through its Phospholipase A2 activity

Peroxiredoxin 6 (Prdx6) has been reported as required for maximal activation of NADPH oxidase (NOX2) in PMN (P. Leavey, JBC 277, 45181, 2002) but the mechanism for this effect is not known. Here we demonstrate that Prdx6 activation of NOX2 in pulmonary endothelium, PMN and macrophages is due to its PLA 2 activity. ROS generation in response to Angiotensin II (Ang II) or phorbol myristic acid (PMA) or fMLF was markedly reduced in Prdx6 null isolated perfused lungs, pulmonary microvascular endothelial cells (PMVEC), PMN and alveolar macrophages. Rac1 and p47phox, cytosolic components of NOX2, translocated to the cell membrane after Ang II treatment in wild type but not Prdx6 null MPMVEC. MJ33 (inhibitor of Prdx6 PLA2) inhibited ROS generation upon agonist treatment by ~85%. Transfection of null cells with full length Prdx6 rescued both PLA 2 activity and Ang II induced ROS generation while mutant transfectants (S32A, H26A, D140A) were ineffective. Ang II treatment of wild type cells resulted in phosphorylation of Prdx6 and its translocation from the cytosol to the cell membrane. Phosphorylation and translocation of Prdx6 and ROS generation were markedly reduced by the MEKK inhibitor, U0126. Thus, phosphorylation of Prdx6 associated with agonist‐induced MAP kinase activation leads to Prdx6 translocation to the membrane where its PLA2 activity facilitates the translocation of NOX2 components and assembly of the oxidase.