Chimeric Protein-Protein Interface Inhibitors Allow Efficient Inhibition of Type III Secretion Machinery and...

Area of Science:

• Microbiology
• Drug Discovery
• Bacterial Pathogenesis

Background:

• Pseudomonas aeruginosa is an opportunistic pathogen with increasing antibiotic resistance.
• Antivirulence strategies targeting bacterial virulence factors offer an alternative to antibiotics.
• The Type III secretion system (T3SS) is a critical virulence factor in P. aeruginosa.

Purpose of the Study:

• To identify small molecules that inhibit the P. aeruginosa T3SS by targeting protein-protein interactions.
• To develop novel antivirulence compounds with reduced toxicity.
• To evaluate the efficacy of these compounds against bacterial cytotoxicity and virulence.

Main Methods:

• Automated target-based screening of small molecule libraries.
• Split/Mix/Click chemistry for hybrid analogue synthesis.
• Phenotypic analysis including automated microscopy and Galleria mellonella infection models.

Main Results:

• Identified compounds inhibiting the PscE-PscG interaction within the T3SS.
• Developed two nontoxic hybrid leads with specific T3SS inhibitory activity.
• Demonstrated reduced ex vivo bacterial cytotoxicity and in vivo virulence in Galleria mellonella.

Conclusions:

• Disrupting T3SS chaperone interactions is a viable antivirulence strategy.
• Novel hybrid compounds effectively inhibit P. aeruginosa T3SS and reduce virulence.
• These findings support the development of T3SS inhibitors as a new class of therapeutics against P. aeruginosa infections.