Structure-based molecular hybridization design and synthesis of Keap1-Nrf2 inhibitors for anti-inflammatory treatment

The Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway stands as a pivotal mechanism in defending against oxidative stress damage and related inflammation. Blocking the Keap1-Nrf2 protein-protein interaction (PPI) offers a promising therapeutic approach for treating diseases related to oxidative stress and inflammation. Our group previously reported NXPZ-2, a naphthalene sulfonamide derivative targeting Keap1, which effectively inhibits the Keap1-Nrf2 PPI, thereby releasing Nrf2 to exert its anti-inflammatory and antioxidant effects. In the present work, we employed a structure-based molecular hybridization strategy to design a series of novel naphthalene sulfonamides by combining NXPZ-2 with the Nrf2 activator dimethyl fumarate (DMF) or its analogues. Among these new derivatives, compound 1c, specifically (Z)-4-((4-(N-(2-amino-2-oxoethyl)-N-(4-((N-(2-amino-2-oxoethyl)-4-methoxyphenyl)sulfonamide)naphthalen-1-yl) sulfamoyl)phenyl)amino)-4-oxobut-2-enoic acid, exhibited the highest PPI inhibitory activity, with a K_D2 value of 0.119 μM. In an LPS-induced RAW264.7 cell model, this compound mitigated LPS-induced cellular damage, suppressed the expression of pro-inflammatory cytokine TNF-α and IL-6, and significantly elevated the intracellular GSH and SOD enzyme activities. Furthermore, in an LPS-induced acute lung injury (ALI) mouse model, the compound demonstrated a remarkable ability to alleviate oxidative damage and inflammation in the lungs. In conclusion, this novel naphthalene sulfonamide represents a promising drug candidate for Keap1-targeting therapy in ALI. Molecular docking analysis revealed that the amide and maleic acid groups of 1c facilitate strong interactions with the Kelch domain of Keap1, explaining the compound's preference for binding through hydrogen bonding and π-π stacking interactions.