New NADPH Oxidase 2 Inhibitors Display Potent Activity against Oxidative Stress by Targeting p22(phox)-p47(phox) Interactions

NADPH oxidase (NOX2) is responsible for reactive oxygen species (ROS) production in neutrophils and has been recognized as a key mediator in inflammatory and cardiovascular pathologies. Nevertheless, there is a lack of specific NOX2 pharmacological inhibitors. In medicinal chemistry, heterocyclic compounds are essential scaffolds for drug design, and among them, indole is a very versatile pharmacophore. We tested the hypothesis that indole heteroaryl-acrylonitrile derivatives may serve as NOX2 inhibitors by evaluating the capacity of 19 of these molecules to inhibit NOX2-derived ROS production in human neutrophils (HL-60 cells). Of these compounds, C6 and C14 exhibited concentration-dependent inhibition of NOX2 (IC(50)~1 µM). These molecules also reduced NOX2-derived oxidative stress in cardiomyocytes and prevented cardiac damage induced by ischemia-reperfusion. Compound C6 significantly reduced the membrane translocation of p47(phox), a cytosolic subunit that is required for NOX2 activation. Molecular docking analyses of the binding modes of these molecules with p47(phox) indicated that C6 and C14 interact with specific residues in the inner part of the groove of p47(phox), the binding cavity for p22(phox). This combination of methods showed that novel indole heteroaryl acrylonitriles represent interesting lead compounds for developing specific and potent NOX2 inhibitors.