LEGO-Lipophosphonoxins: A Novel Approach in Designing Membrane Targeting Antimicrobials

Area of Science:

• Medicinal Chemistry
• Microbiology
• Drug Discovery

Background:

• Bacterial antibiotic resistance is a growing global health threat.
• Existing antibiotic classes are becoming less effective.
• Lipophosphonoxins (LPPOs) show antibacterial activity but are inhibited by serum albumin.

Purpose of the Study:

• To synthesize and evaluate novel LEGO-lipophosphonoxin (LEGO-LPPO) compounds.
• To overcome the inhibitory effect of serum albumin on LPPO activity.
• To explore the structure-activity relationship of LEGO-LPPOs for enhanced antibacterial efficacy.

Main Methods:

• Synthesis of LEGO-LPPO analogs with modular components (linker, connectors, polar/hydrophobic modules).
• Structure-activity relationship studies by systematically altering linker and hydrophobic module lengths.
• In vitro evaluation of antibacterial activity against Gram-negative and Gram-positive bacteria, including resistant strains and persisters.
• Assessment of mechanism of action, including membrane potential disruption and pore formation.
• Evaluation of compound efficacy in the presence of serum albumin.
• Cytotoxicity and resistance development propensity assays.

Main Results:

• LEGO-LPPOs were synthesized and demonstrated broad-spectrum activity against Gram-negative and Gram-positive bacteria.
• Compounds were effective against multidrug-resistant strains and bacterial persisters.
• Activity was maintained in the presence of serum albumin, a key improvement over previous LPPOs.
• Mechanism involves initial depletion of membrane potential followed by pore formation in the cytoplasmic membrane.
• LEGO-LPPOs exhibited low cytotoxicity and low propensity for resistance development.

Conclusions:

• LEGO-LPPOs represent a novel class of antibacterial agents with significant potential.
• Their modular design allows for optimization of activity and overcomes serum albumin inhibition.
• The dual mechanism of action and favorable resistance profile suggest therapeutic viability for treating resistant bacterial infections.