Broad Spectrum Pro-Quorum-Sensing Molecules as Inhibitors of Virulence in Vibrios

Vibrio cholerae The disease cholera, caused by the pathogenic bacterium Vibrio cholerae, is a major health concern in developing regions. In order to be virulent, V. cholerae must precisely control the timing of production of virulence factors. To do this, V. cholerae uses a cell-cell communication process called quorum sensing to regulate pathogenicity.

This paper identifies and characterises new classes of small molecules that interfere with quorum-sensing-control of virulence in multiple Vibrio species. The molecules target the key quorum-sensing regulator LuxO. These molecules have the potential to be developed into new anti-infectives to combat infectious diseases of global importance.

 

Broad Spectrum Pro-Quorum-Sensing Molecules as Inhibitors of Virulence in Vibrios. (2012) PLoS Pathog 8(6): e1002767. doi:10.1371/journal.ppat.1002767
Quorum sensing (QS) is a bacterial cell-cell communication process that relies on the production and detection of extracellular signal molecules called autoinducers. QS allows bacteria to perform collective activities. Vibrio cholerae, a pathogen that causes an acute disease, uses QS to repress virulence factor production and biofilm formation. Thus, molecules that activate QS in V. cholerae have the potential to control pathogenicity in this globally important bacterium. Using a whole-cell high-throughput screen, we identified eleven molecules that activate V. cholerae QS: eight molecules are receptor agonists and three molecules are antagonists of LuxO, the central NtrC-type response regulator that controls the global V. cholerae QS cascade. The LuxO inhibitors act by an uncompetitive mechanism by binding to the pre-formed LuxO-ATP complex to inhibit ATP hydrolysis. Genetic analyses suggest that the inhibitors bind in close proximity to the Walker B motif. The inhibitors display broad-spectrum capability in activation of QS in Vibrio species that employ LuxO. To the best of our knowledge, these are the first molecules identified that inhibit the ATPase activity of a NtrC-type response regulator. Our discovery supports the idea that exploiting pro-QS molecules is a promising strategy for the development of novel anti-infectives.

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