Cell-based screen for discovering lipopolysaccharide biogenesis inhibitors

Area of Science:

• Microbiology
• Drug Discovery
• Cell Biology

Background:

• Gram-negative bacteria possess a challenging outer membrane barrier, hindering antibiotic efficacy.
• Lipopolysaccharide (LPS) in the outer leaflet is crucial for this permeability barrier.
• Targeting LPS biosynthesis presents a viable strategy against gram-negative infections.

Purpose of the Study:

• To develop a cell-based screen for identifying inhibitors of LPS biosynthesis and transport.
• To discover novel antibacterial compounds targeting essential pathways in gram-negative bacteria.
• To validate MsbA as a potential antibacterial target.

Main Methods:

• Developed a cell-based screening assay leveraging the nonessentiality of LPS biogenesis in Acinetobacter.
• Utilized the screen to identify inhibitors of LPS transport.
• Focused on MsbA, an ATP-dependent flippase essential for LPS translocation.

Main Results:

• Successfully identified an inhibitor of MsbA, an ATP-dependent flippase.
• Observed mislocalization of LPS to the cell interior upon treatment with the MsbA inhibitor.
• Validated MsbA as a universally conserved antibacterial target in gram-negative bacteria.

Conclusions:

• MsbA is a validated target for developing new antibacterial drugs against gram-negative pathogens.
• The developed cell-based screen can identify inhibitors targeting various steps in LPS biogenesis.
• This approach offers insights into gram-negative cell envelope vulnerabilities for future drug development.