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

Appl Environ Microbiol. 2019 Apr 4;85(8):e00105-19. doi: 10.1128/AEM.00105-19. Print 2019 Apr 15.

Abstract

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-C16: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-C16:Δ2 also reduced AHL signal production. Genetic and biochemical analyses showed that 14-Me-C16:Δ2 inhibited the production of the BDSF and AHL signals by decreasing the expression of their synthase-encoding genes. Notably, 14-Me-C16:Δ2 attenuated BDSF-regulated phenotypes in various Burkholderia species. These findings suggest that 14-Me-C16: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-2-enoic acid [14-Me-C16:Δ2]) that is capable of interfering with B. cenocepacia QS signaling and virulence. We demonstrate that 14-Me-C16: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-C16:Δ2 could interfere with QS signaling in many Burkholderia species and might be developed as a new antibacterial agent.

Keywords: AHL; BDSF; Burkholderia cenocepacia; quorum sensing; virulence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyl-Butyrolactones / metabolism
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Biofilms / drug effects
  • Burkholderia Infections / microbiology
  • Burkholderia Infections / prevention & control
  • Burkholderia cenocepacia / drug effects*
  • Burkholderia cenocepacia / genetics
  • Burkholderia cenocepacia / metabolism
  • Cyclic GMP / analogs & derivatives
  • Cyclic GMP / metabolism
  • Fatty Acids, Monounsaturated / antagonists & inhibitors*
  • Fatty Acids, Monounsaturated / pharmacology*
  • Gene Expression Regulation, Bacterial
  • Microbial Sensitivity Tests
  • Phenotype
  • Quorum Sensing / drug effects*
  • Signal Transduction
  • Virulence / drug effects
  • Virulence / genetics

Substances

  • 2-dodecenoic acid
  • Acyl-Butyrolactones
  • Bacterial Proteins
  • Fatty Acids, Monounsaturated
  • bis(3',5')-cyclic diguanylic acid
  • Cyclic GMP