Mapping pilicide anti-virulence effect in Escherichia coli, a comprehensive structure-activity study

Area of Science:

• Microbiology
• Medicinal Chemistry
• Computational Chemistry

Background:

• Bacterial biofilms contribute to persistent infections and antimicrobial resistance.
• Pili, hair-like appendages on bacteria, are crucial for biofilm formation.
• Pilicides are compounds designed to inhibit pili formation and prevent biofilms.

Purpose of the Study:

• To conduct a comprehensive structure-activity relationship (SAR) study of dihydrothiazolo ring-fused 2-pyridone pilicides.
• To identify key structural features influencing the efficacy of pilicides against bacterial biofilms.
• To develop potent inhibitors of type 1 pili-dependent biofilm formation in Escherichia coli.

Main Methods:

• Systematic variation of substituents on the pilicide central fragment.
• Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) for compound classification.
• Quantitative Structure-Activity Relationship (QSAR) modeling using Partial Least Squares (PLS).

Main Results:

• Polarity was identified as a critical factor for discriminating active from inactive pilicides.
• QSAR modeling indicated that potent inhibitors are generally larger, more lipophilic, more flexible, and possess a lower HOMO energy.
• The most effective pilicide demonstrated significant inhibitory activity with an EC(50) of 400 nM.

Conclusions:

• This study provides valuable SAR insights into the design of effective pilicides.
• Potent inhibitors of type 1 pili-dependent biofilm formation were identified.
• The findings contribute to the development of novel strategies to combat bacterial biofilm-related infections.