Flavones as Quorum Sensing Inhibitors Identified by a Newly Optimized Screening Platform Using Chromobacterium violaceum as Reporter Bacteria.
Quorum sensing (QS) is the process by which bacteria produce and detect signal molecules to coordinate their collective behavior. This intercellular communication is a relevant target for anti-biofilm therapies. Here we have optimized a screening-applicable assay to search for new quorum sensing inhibitors from natural compound libraries. In this system, QS is correlated with the production of violacein, which is directly controlled by the LuxI/LuxR system in Chromobacterium violaceum ATCC 31532. The parallel use of C. violaceum Tn5-mutant CV026, which depends on auto-inducer addition, allows simultaneous discrimination of compounds that act as quenchers of the AHL signal (quorum quenchers). The incorporation of a redox stain into the platform allowed further distinction between QS inhibitors, quorum quenchers and antibacterial compounds. A pilot screening was performed with 465 natural and synthetic flavonoids. All the most active compounds were flavones and they displayed potencies (IC50) in the range of 3.69 to 23.35 μM. These leads were particularly promising as they inhibited the transition from microcolonies into mature biofilms from Escherichia coli and Pseudomonas aeruginosa strains. This approach can be very effective in identifying new antimicrobials posing lesser risks of resistance.
Pharmaceutical Design and Discovery Group (PharmDD), Division of Pharmaceutical Biosciences, Faculty of Pharmacy, Viikinkaari 5E, University of Helsinki, FI-00014 Helsinki, Finland. malena.skogman@helsinki.fi.
Malena E
ME
Skogman
Pharmaceutical Design and Discovery Group (PharmDD), Division of Pharmaceutical Biosciences, Faculty of Pharmacy, Viikinkaari 5E, University of Helsinki, FI-00014 Helsinki, Finland. sonja.kanerva@helsinki.fi.
Sonja
S
Kanerva
Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Abo Akademi University, BioCity, Artillerigatan 6 A, FI-20520 Turku, Finland. suvi.manner@abo.fi.
Suvi
S
Manner
Pharmaceutical Design and Discovery Group (PharmDD), Division of Pharmaceutical Biosciences, Faculty of Pharmacy, Viikinkaari 5E, University of Helsinki, FI-00014 Helsinki, Finland. pia.vuorela@helsinki.fi.
Pia M
PM
Vuorela
Pharmaceutical Design and Discovery Group (PharmDD), Division of Pharmaceutical Biosciences, Faculty of Pharmacy, Viikinkaari 5E, University of Helsinki, FI-00014 Helsinki, Finland. adyary.fallarero@helsinki.fi.
Adyary
A
Fallarero
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D002861:Chromobacterium / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000502:physiology*; D047309:Flavones / Q000737:chemistry / Q000494:pharmacology; D007211:Indoles / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000502:physiology*; D053038:Quorum Sensing / Q000187:drug effects*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D047309:Flavones; D007211:Indoles; C085427:LuxI protein, Bacteria; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C064778:LuxR autoinducer binding proteins; C063155:violacein
Chromobacterium violaceum; anti-biofilm; assay optimization; flavones; flavonoids; microcolonies; quorum sensing; quorum sensing inhibition; screening; violacein quantification