Finding NOX2 inhibitors: Targeting regulatory subunits for isoform selectivity

抄録

NADPH oxidase 2 (NOX2) represents a potential therapeutic target for inflammatory disorders. However, clinically applicable NOX2 inhibitors have yet to be available despite extensive research efforts. In our quest for NOX2 inhibitors, we focused on the regulatory subunit p40^phox, which exclusively functions with NOX2, rather than the catalytic subunit gp91^phox, aiming to impede the complete assembly of the NOX2 complex. Chemical compounds were designed to interfere with the interaction between the PX domain in p40^phox and its ligand phosphatidylinositol 3-phosphate (PI3P), and screened for their inhibitory potential, leading to the finding of a hit DG401. DG401 exhibited inhibitory activity against NOX2 in cells within the range of 0.1–10 μM, with high selectivity over other NOX isoforms. Indeed, it disrupted the interaction between p40^phox and PI3P, and prevented the recruitment of p40^phox to the phagosomal membrane during zymosan phagocytosis. In animal model, it displayed oral efficacy in attenuating complete Freund's adjuvant (CFA)-induced inflammation and reactive oxygen species generation. This study provides substantial support for the conceptual rationale that the pharmacological inhibition of NOX2 serves as a viable strategy for treating immuno-inflammatory disorders. In addition, it underscores the potential of regulatory subunits such as p40^phox as promising targets for selectively inhibiting NOX isoforms.