Activity Assay: Nox2 activity assay for primary screening: Plasma membranes were prepared from human neutrophils, which express large amounts of Nox2, stored at −80 C until use. See Curnutte et al., J. Biol. Chem. 1987, 262, 6450-6452, hereby incorporated by reference. Membranes are mixed with recombinant, purified cytosolic regulatory proteins (p67Np47N chimera, and a constitutively active mutant of Rac, Rac1(Q61)) and FAD, along with varying concentrations of compound, and LO12, which emits light when it reacts with ROS. The reaction is initiated by addition of NADPH and SDS (an artificial activator of Nox2).Nox2 assay in human neutrophils: Human neutrophils were obtained from healthy volunteers (REF). LO12 luminescence was quantified as above. Nox4 assay using stably transfected HEK cell: HEK cells stably transfected with human Nox4 were incubated with varying concentrations of compound along with LO12.
Control Assay: Assay controls. To rule out interference with either Nox2 or Nox4 luminescence assays, two approaches are used. In one, xanthine oxidase replaces the Nox2 enzymatic system as the source of ROS in the Nox2/LO12 assay. Xanthine is added to initiate the reaction and LO12 luminescence is recorded. In the other, exogenous H2O2 is supplied in place of the Nox4 expressing H2O2-generating cells and luminescence is recorded.