Lactonase Specificity Is Key to Quorum Quenching in <i>Pseudomonas aeruginosa</i>

Abstract

Background: Pseudomonas aeruginosa orchestrates the expression of many genes by using quorum sensing (QS) communication process. QS relies on an intricate molecular network including two acyl-homoserine lactones (AHL), involved in the modulation of virulence factors production, biofilm formation or antimicrobial sensitivity. Disrupting QS is a promising approach to modulate virulence while not challenging bacterial survival and can be achieved with AHL-degrading lactonases. Methods: Here, we used two lactonases both targeting the signal molecules N-(3-oxododecanoyl)-L-Homoserine lactone (3-oxo-C12 HSL) and butyryl-homoserine lactone (C4 HSL) albeit with different efficacy on C4 HSL. We used phenotypic analyses to characterize the specific impact of each lactonases on P. aeruginosa virulence. We further used molecular approaches for finely determine the impact of lactonases on gene regulation and protein expressions of P. aeruginosa. Findings: Although, both lactonases similarly impacted AHL-based circuits, strong variations were however observed in Pseudomonas Quinolone Signal regulation yielding in different impacts on phenotypic traits related to virulence, biofilm, pathogenicity or antibiotic susceptibility. Proteomic analysis further allowed to identify the specific impacts of lactonases on P. aeruginosa behavior. Interpretation: This global analysis provides the first evidence that QQ enzyme specificity is crucial to modulate QS-associated behavior in P. aeruginosa PA14 and will help to develop efficient quorum quenching strategies. Funding Statement: This work was supported by a project RAPID (LACTO-TEX) from Direction Generale de l'Armement (DGA, France), Investissements d'avenir program (Mediterranee Infection 10-IAHU-03) of the French Agence Nationale de la Recherche (ANR), Emplois Jeunes Doctorants program of Region Provence-Alpes-Cote d'Azur (PACA, France) and MnDrive initiative. Declaration of Interests: ME and EC have a patent WO2014167140 A1 licensed to Gene&GreenTK. LP, DD, BR, ME and EC report personal fees from Gene&GreenTK during the conduct of the study. The other authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Ethics Approval Statement: Not required.