Repurposing Tirazone as an Effective Quorum Sensing Inhibitor Against Pseudomonas aeruginosa Virulence and Biofilm Formation (raw data)

Antibiotic resistance has emerged as a critical global public health challenge. Quorum sensing (QS), a density-dependent regulatory mechanism, plays a pivotal role in bacterial pathogenesis by coordinating virulence factor expression, making it a critical target for antivirulence therapy. Leveraging a drug repositioning strategy, this study systematically investigated the antivirulence potential and mechanism by which Tirazone modulates the QS-related pathogenicity of Pseudomonas aeruginosa. Molecular docking analysis predicted that Tirazone could bind to the core QS regulatory proteins, LasR, RhlR, and PqsR of P. aeruginosa with abundant active sites, whereas the binding free energies were higher than those of the native QS signals. In vitro experiments demonstrated that Tirazone significantly suppressed virulence factor secretion, cell motilities, and biofilm formation in the model P. aeruginosa strain PAO1, and downregulated the expression of a series of QS-related genes with low effective concentration (£ 8 μM). A competitive binding model of QS signal molecules further elucidated that Tirazone interfered with QS signaling by competitively inhibiting the function of LasR, RhlR, and PqsR. Additionally, Tirazone treatment significantly protected Caenorhabditis elegans and mouse models from P. aeruginosa PAO1 infection, and Tirazone treated mice exhibited reduced bacterial load and less pathological lesion in the lung tissues. Moreover, Tirazone demonstrated synergistic effects with polymyxin B, levofloxacin, and amikacin, significantly enhancing their bactericidal efficacy in treating P. aeruginosa. This study reveals the molecular mechanism underlying Tirazone’s multi-target intervention in the QS system, and provides an experimental foundation for developing combination therapies based on antivirulence strategies.