“…The generation of ROS has also been implicated in several human disorders, including hypertension, atherosclerosis, ischemia/reperfusion injury, neurodegenerative disease, chronic granulomatous disease, and the deleterious effects of aging [18,56]. The use of ROS by leukocytes in the defense against pathogens is well recognized, but the role of ROS as second messengers is sill emerging, e.g., ROS generation has been linked to the activation of transcription factors, including apurinic/apyrimidinic endonuclease 1 (APE1)/Ref1, nuclear factor κB (NFκB), and AP-1, as well as the signaling kinases p90 ribosomal S6 kinase (p90RSK) and various MAPKs [21,[57][58][59][60][61][62][63][64][65]. Although the mechanisms of ROS-induced signaling have not been fully resolved, multiple processes including inactivation of phosphatases through cysteine modification and the activation of redox sensitive systems, have been proposed [57,61,62,66].…”