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Anti-virulent Disruption of Pathogenic Biofilms using Engineered Quorum-quenching Lactonases
Published on: January 1, 2016
ML364 exerts the broad-spectrum antivirulence effect by interfering with the bacterial quorum sensing system
Youwen Zhang1, Limin Dong2, Lang Sun1
1Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Abstract:
Antivirulence strategy has been developed as a nontraditional therapy which would engender a lower evolutionary pressure toward the development of antimicrobial resistance. However, the majority of the antivirulence agents currently in development could not meet clinical needs due to their narrow antibacterial spectrum and limited indications. Therefore, our main purpose is to develop broad-spectrum antivirulence agents that could target on both Gram-positive and Gram-negative pathogens. We discovered ML364, a novel scaffold compound, could inhibit the productions of both pyocyanin of Pseudomonas aeruginosa and staphyloxanthin of Staphylococcus aureus. Further transcriptome sequencing and enrichment analysis showed that the quorum sensing (QS) system of pathogens was mainly disrupted by ML364 treatment. To date, autoinducer-2 (AI-2) of the QS system is the only non-species-specific signaling molecule that responsible for the cross-talk between Gram-negative and Gram-positive species. And further investigation showed that ML364 treatment could significantly inhibit the sensing of AI-2 or its nonborated form DPD signaling in Vibrio campbellii MM32 and attenuate the biofilm formation across multi-species pathogens including Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. The results of molecular docking and MM/GBSA free energy prediction showed that ML364 might have higher affinity with the receptors of DPD/AI-2, when compared with DPD molecule. Finally, the in vivo study showed that ML364 could significantly improve the survival rates of systemically infected mice and attenuate bacterial loads in the organs of mice. Overall, ML364 might interfere with AI-2 quorum sensing system to exert broad-spectrum antivirulence effect both in vitro and in vivo.
Insights
A novel compound, ML364, effectively targets the autoinducer-2 (AI-2) quorum sensing system, offering broad-spectrum antivirulence against Gram-positive and Gram-negative bacteria. This approach reduces resistance pressure and shows promise in improving survival rates in vivo.
Area of Science:
- Microbiology
- Drug Discovery
- Antimicrobial Resistance
Background:
- Antivirulence strategies offer a promising alternative to traditional antibiotics, potentially reducing antimicrobial resistance.
- Current antivirulence agents often exhibit narrow-spectrum activity, limiting their clinical applicability.
- There is a critical need for broad-spectrum antivirulence agents effective against both Gram-positive and Gram-negative pathogens.
Purpose of the Study:
- To develop novel, broad-spectrum antivirulence agents targeting both Gram-positive and Gram-negative bacteria.
- To investigate the mechanism of action of a newly discovered compound, ML364.
- To evaluate the efficacy of ML364 in vitro and in vivo.
Main Methods:
- Screening for compounds inhibiting virulence factors like pyocyanin and staphyloxanthin.
- Transcriptome sequencing to identify pathways affected by ML364.
- Quorum sensing inhibition assays using autoinducer-2 (AI-2) and its nonborated form (DPD).
- Biofilm formation assays across multiple bacterial species.
- Molecular docking and MM/GBSA free energy calculations.
- In vivo efficacy studies in a mouse infection model.
Main Results:
- ML364 inhibited pyocyanin production in *Pseudomonas aeruginosa* and staphyloxanthin in *Staphylococcus aureus*.
- Transcriptome analysis revealed disruption of pathogen quorum sensing (QS) systems by ML364.
- ML364 inhibited AI-2/DPD signaling and attenuated biofilm formation in *P. aeruginosa*, *Escherichia coli*, *Klebsiella pneumoniae*, and *S. aureus*.
- Molecular modeling suggested ML364 has a high affinity for AI-2/DPD receptors.
- In vivo studies demonstrated ML364 significantly improved survival rates and reduced bacterial loads in infected mice.
Conclusions:
- ML364 is a novel broad-spectrum antivirulence compound that targets the AI-2 quorum sensing system.
- ML364 demonstrates efficacy against both Gram-positive and Gram-negative pathogens, reducing virulence and improving outcomes in vivo.
- ML364 represents a promising therapeutic candidate for combating bacterial infections with reduced risk of resistance development.
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