Targeting microbial β-CAs: bridging in silico screening with in vitro validation

Area of Science:

• Microbiology
• Medicinal Chemistry
• Drug Discovery

Background:

• Antimicrobial resistance (AMR) poses a significant global health challenge, necessitating novel therapeutic strategies.
• Pseudomonas aeruginosa is a critical pathogen associated with high resistance rates, particularly in vulnerable patient populations.
• Beta-carbonic anhydrases (β-CAs) represent a potential druggable target for combating bacterial infections.

Purpose of the Study:

• To identify and validate novel inhibitors of Pseudomonas aeruginosa beta-carbonic anhydrase (PsCA3).
• To explore new chemical scaffolds for targeting microbial β-CAs with high selectivity over human carbonic anhydrases (hCAs).

Main Methods:

• A consensus structure-based virtual screening approach was employed to identify potential PsCA3 inhibitors from a library of 607 small molecules.
• Experimental validation involved enzyme inhibition assays to assess the inhibitory activity of selected compounds against PsCA3.
• Selectivity was evaluated by testing compounds against human alpha-carbonic anhydrases (hCAs).
• Further optimization and testing involved benzoxazinone/dihydroquinolinone scaffolds and additional microbial β-CAs.

Main Results:

• Twenty-one diverse compounds were initially selected and validated for PsCA3 inhibition.
• Potent inhibitors targeting microbial β-CAs were identified, demonstrating activity at micromolar and submicromolar concentrations.
• Remarkable selectivity was observed, with identified ligands effectively sparing human carbonic anhydrases.
• Novel scaffolds beyond the initial focus were discovered, expanding the chemical space for β-CA inhibitors.

Conclusions:

• The study successfully identified novel, potent, and selective inhibitors of microbial beta-carbonic anhydrases, specifically targeting Pseudomonas aeruginosa.
• These findings highlight PsCA3 as a viable drug target and provide promising lead compounds for the development of new antibacterial agents to combat AMR.
• The identified compounds and scaffolds offer a foundation for future drug development efforts against resistant bacterial infections.