A dual-targeting strategy: Novel 6-substituted 3-Hydroxypyridin-4(1H)-one-hydroxamate conjugates against Pseudomonas aeruginosa biofilm

Pseudomonas aeruginosa is a formidable Gram-negative threat in clinics, where its extensive Antibiotic resistance is largely rooted in a remarkable capacity for biofilm formation. There is a complex interplay between iron metabolism and quorum sensing, which collectively coordinate the formation and development of biofilms. In this work, a series of novel 6-substituted 3-hydroxypyridin-4(1H)-one-conjugated hydroxamic acid derivatives were designed as dual-effect biofilm inhibitors with quorum sensing inhibition and iron chelation. Structure-activity relationship analysis identified 6-substituted 3-hydroxypyridin-4-one derivative 5j as the most potent one, with an IC₅₀ of 2.66 ± 0.46 μM against P. aeruginosa biofilm formation. Mechanistic studies revealed that 5j simultaneously disrupts key QS pathways (las, pqs, and rhl), significantly reducing the production of virulence factors. Concurrently, 5j acts as a potent iron chelator, competitively depriving bacteria of essential iron. Transcriptomics and molecular modeling revealed that this iron starvation, potentially facilitated by interaction with the FpvA receptor, triggers severe metabolic dysregulation. Moreover, in a wound Infection mouse model, 5j enhanced the efficacy of the first-line drug tobramycin by 1000-fold compared to tobramycin alone. In conclusion, this study confirms that compound 5j functions as a dual-action inhibitor against Bacterial biofilms by targeting the QS system and iron homeostasis. By inhibiting biofilm formation and potentiating Antibiotic efficacy, it emerges as a highly promising synergistic agent for the treatment of Bacterial infections.