Cyclic Diguanylate G-Quadruplex Inducer-Quorum Sensing Inhibitor Hybrids as Bifunctional Anti-biofilm and Anti-virulence Agents Against <i>Pseudomonas aeruginosa</i>

The release of virulence factors and biofilm formation by <i>Pseudomonas aeruginosa</i> are pivotal drivers of its severe pathogenicity and antibiotic resistance. Based on our prior findings, cyclic di-GMP (c-di-GMP) G-quadruplex inducers are promising biofilm inhibitors and that quorum sensing systems are central regulators of virulence, we aimed to design and synthesize c-di-GMP G-quadruplex inducer-quorum sensing inhibitor hybrids. These hybrids were envisioned as bifunctional agents with both antibiofilm and antivirulence capabilities. Hybrids <b>A7</b> and <b>A11</b>, characterized by their quinoline and 3-indole rings, emerged as potent inhibitors. They achieve this dual action by inducing c-di-GMP G-quadruplex formation and disrupting the <i>las</i> and <i>pqs</i> signaling system. Additionally, hybrids <b>A7</b> and <b>A11</b> attenuated virulence factors and inhibited the motility phenotypes of <i>P. aeruginosa</i>. Furthermore, when tested in <i>in vivo</i> <i>Caenorhabditis elegans</i> infection models, these hybrids, in combination with antibiotics such as tetracycline, improved survival rates, all while maintaining a favorable biosafety profile.