Discovery of new diketopiperazines inhibiting Burkholderia cenocepacia quorum sensing in vitro and in vivo

Scoffone, Viola Camilla; Chiarelli, Laurent R.; Makarov, Vadim; Brackman, Gilles; Israyilova, Aygun; Azzalin, Alberto; Forneris, Federico; Riabova, Olga; Savina, S. V.; Coenye, Tom; Riccardi, Giovanna; Buroni, Silvia

doi:10.1038/srep32487

Cited by 44 publications

(46 citation statements)

References 52 publications

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“…Determination of CepI activity in the presence of BH. B. cenocepacia CepI was expressed in Escherichia coli BL21(DE3) cells and purified according to a previously described procedure (56). The enzymatic activity was determined by a spectrophotometric assay according to Christensen et al (57), which measures the holo-ACP formation by titrating the release of the free thiol of ACP with dichlorophenylindophenol (DCPIP; ϭ 19,100 M Ϫ1 cm Ϫ1 ).…”

Section: Methodsmentioning

confidence: 99%

Various Evolutionary Trajectories Lead to Loss of the Tobramycin-Potentiating Activity of the Quorum-Sensing Inhibitor Baicalin Hydrate in Burkholderia cenocepacia Biofilms

Saß

Slachmuylders

Acker

et al. 2019

Antimicrob Agents Chemother

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Combining antibiotics with potentiators that increase their activity is a promising strategy to tackle infections caused by antibiotic-resistant bacteria. As potentiators do not interfere with essential processes, it has been hypothesized that they are less likely to induce resistance. However, evidence supporting this hypothesis is lacking. In the present study, we investigated whether Burkholderia cenocepacia J2315 biofilms develop reduced susceptibility toward one such adjuvant, baicalin hydrate (BH). Biofilms were repeatedly and intermittently treated with tobramycin (TOB) alone or in combination with BH for 24 h. After treatment, the remaining cells were quantified using plate counting. After 15 cycles, biofilm cells were less susceptible to TOB and TOBϩBH compared to the start population, and the potentiating effect of BH toward TOB was lost. Whole-genome sequencing was performed to probe which changes were involved in the reduced effect of BH, and mutations in 14 protein-coding genes were identified (including mutations in genes involved in central metabolism and in BCAL0296, encoding an ABC transporter). No changes in the MIC or MBC of TOB or changes in the number of persister cells were observed. However, basal intracellular levels of reactive oxygen species (ROS) and ROS levels found after treatment with TOB were markedly decreased in the evolved populations. In addition, in evolved cultures with mutations in BCAL0296, a significantly reduced uptake of TOB was observed. Our results indicate that B. cenocepacia J2315 biofilms rapidly lose susceptibility toward the antibiotic-potentiating activity of BH and point to changes in central metabolism, reduced ROS production, and reduced TOB uptake as mechanisms.

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Section: Methodsmentioning

confidence: 99%

Various Evolutionary Trajectories Lead to Loss of the Tobramycin-Potentiating Activity of the Quorum-Sensing Inhibitor Baicalin Hydrate in Burkholderia cenocepacia Biofilms

Saß

Slachmuylders

Acker

et al. 2019

Antimicrob Agents Chemother

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“…During the last few years, we focused our attention on this topic, proposing new targets, such as the glutamate racemase (Israyilova et al, 2016), new strategies, such as the inhibition of quorum sensing (Scoffone et al, 2016;Buroni et al, 2018) and new drugs (Scoffone et al, 2014), to fight B. cenocepacia infections. We found that the benzothiadiazole derivative C109 is highly effective against B. cenocepacia (Scoffone et al, 2015) and other Gram-negative and-positive bacteria, including Mycobacterium abscessus (Hogan et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Chemical, Metabolic, and Cellular Characterization of a FtsZ Inhibitor Effective Against Burkholderia cenocepacia

et al. 2020

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There is an urgent need for new antimicrobials to treat the opportunistic Gram-negative Burkholderia cenocepacia, which represents a problematic challenge for cystic fibrosis patients. Recently, a benzothiadiazole derivative, C109, was shown to be effective against the infections caused by B. cenocepacia and other Gram-negative and-positive bacteria. C109 has a promising cellular target, the cell division protein FtsZ, and a recently developed PEGylated formulation make it an attractive molecule to counteract Burkholderia infections. However, the ability of efflux pumps to extrude it out of the cell represents a limitation for its use. Here, more than 50 derivatives of C109 were synthesized and tested against Gram-negative species and the Gram-positive Staphylococcus aureus. In addition, their activity was evaluated on the purified FtsZ protein. The chemical, metabolic and cellular stability of C109 has been assayed using different biological systems, including quantitative single-cell imaging. However, no further improvement on C109 was achieved, and the role of efflux in resistance was further confirmed. Also, a novel nitroreductase that can inactivate the compound was characterized, but it does not appear to play a role in natural resistance. All these data allowed a deep characterization of the compound, which will contribute to a further improvement of its properties.

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“…In particular, the development of QS inhibitors as novel drugs to treat bacterial infections has attracted significant attention over the past 20 years (18-21, 23-27, 36). For example, a number of compounds have been screened and identified or synthesized as antagonists of QS systems, including diketopiperazines (37) and baicalein (38). The compounds with activities that interfere with the BDSF QS significantly inhibit B. cenocepacia virulence, suggesting that interference in QS signaling can be used as favorable therapeutic method to treat B. cenocepacia infections.…”

Section: Discussionmentioning

confidence: 99%

Disruption of Quorum Sensing and Virulence in Burkholderia cenocepacia by a Structural Analogue of the cis -2-Dodecenoic Acid Signal

Cui

Song

Yang

et al. 2019

Appl Environ Microbiol

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Quorum sensing (QS) signals are widely used by bacterial pathogens to control biological functions and virulence in response to changes in cell population densities. Burkholderia cenocepacia employs a molecular mechanism in which the cis-2-dodecenoic acid (named Burkholderia diffusible signal factor [BDSF]) QS system regulates N-acyl homoserine lactone (AHL) signal production and virulence by modulating intracellular levels of cyclic diguanosine monophosphate (c-di-GMP). Thus, inhibition of BDSF signaling may offer a non-antibiotic-based therapeutic strategy against BDSF-regulated bacterial infections. In this study, we report the synthesis of small-molecule mimics of the BDSF signal and evaluate their ability to inhibit BDSF QS signaling in B. cenocepacia. A novel structural analogue of BDSF, 14-Me-C 16:Δ2 (cis-14-methylpentadec-2-enoic acid), was observed to inhibit BDSF production and impair BDSF-regulated phenotypes in B. cenocepacia, including motility, biofilm formation, and virulence, while it did not inhibit the growth rate of this pathogen. 14-Me-C 16:Δ2 also reduced AHL signal production. Genetic and biochemical analyses showed that 14-Me-C 16:Δ2 inhibited the production of the BDSF and AHL signals by decreasing the expression of their synthase-encoding genes. Notably, 14-Me-C 16:Δ2 attenuated BDSF-regulated phenotypes in various Burkholderia species. These findings suggest that 14-Me-C 16:Δ2 could potentially be developed as a new therapeutic agent against pathogenic Burkholderia species by interfering with their QS signaling. IMPORTANCE Burkholderia cenocepacia is an important opportunistic pathogen which can cause life-threatening infections in susceptible individuals, particularly in cystic fibrosis and immunocompromised patients. It usually employs two types of quorum sensing (QS) systems, including the cis-2-dodecenoic acid (BDSF) system and N-acyl homoserine lactone (AHL) system, to regulate virulence. In this study, we have designed and identified an unsaturated fatty acid compound (cis-14-methylpentadec-2enoic acid [14-Me-C 16:Δ2 ]) that is capable of interfering with B. cenocepacia QS signaling and virulence. We demonstrate that 14-Me-C 16:Δ2 reduced BDSF and AHL signal production in B. cenocepacia. It also impaired QS-regulated phenotypes in various Burkholderia species. These results suggest that 14-Me-C 16:Δ2 could interfere with QS signaling in many Burkholderia species and might be developed as a new antibacterial agent.

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Discovery of new diketopiperazines inhibiting Burkholderia cenocepacia quorum sensing in vitro and in vivo

Cited by 44 publications

References 52 publications

Various Evolutionary Trajectories Lead to Loss of the Tobramycin-Potentiating Activity of the Quorum-Sensing Inhibitor Baicalin Hydrate in Burkholderia cenocepacia Biofilms

Various Evolutionary Trajectories Lead to Loss of the Tobramycin-Potentiating Activity of the Quorum-Sensing Inhibitor Baicalin Hydrate in Burkholderia cenocepacia Biofilms

Chemical, Metabolic, and Cellular Characterization of a FtsZ Inhibitor Effective Against Burkholderia cenocepacia

Disruption of Quorum Sensing and Virulence in Burkholderia cenocepacia by a Structural Analogue of the cis -2-Dodecenoic Acid Signal

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