Enhanced Gram-Negative Membrane Disruption and In Vivo Efficacy via Lysine-Arginine Enrichment of Opis16a
Mandelie van der Walt1, Carel B Oosthuizen2, Miruna Serian3
1Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria 0002, South Africa.
Abstract:
Infections complicate burn wound care, especially with the rise of antimicrobial resistance. Antimicrobial peptides (AMPs) offer the potential for advancing wound care by combating persistent infections. Opis16a, a scorpion venom-derived AMP, exhibits potent antibacterial activity by targeting Gram-negative membranes, causing rapid membrane disruption and bacterial cell death. Here, four novel Opis16a analogues were developed with improved membrane targeting and antibacterial efficacy. One analogue shows particular promise for topical application in Gram-negative burn wound infections. Enhanced peptide-lipid hydrogen bonding increases conformational stability, membrane insertion, and permeabilization rates. Substituting lysine residues in the C-terminal with arginine leads to the most consistent improvement in activity, selectivity for pathogen over HaCat cells, and stability in serum. In an in vivo Galleria mellonella burn wound model, a 5 mg/kg topical dose provides better protection than Opis16a against Enterobacter cloacae NICD 16103. These findings highlight the potential of optimized bactericidal AMPs to improve burn wound care.
Insights
Novel antimicrobial peptides (AMPs) show promise for treating burn wound infections. Optimized analogues of Opis16a demonstrate enhanced efficacy against Gram-negative bacteria, offering new therapeutic potential.
Area of Science:
- Biochemistry
- Microbiology
- Wound Care Research
Background:
- Burn wound infections are a significant clinical challenge, exacerbated by increasing antimicrobial resistance.
- Antimicrobial peptides (AMPs) present a promising therapeutic avenue for combating persistent bacterial infections in wounds.
- Opis16a, a scorpion-derived AMP, effectively targets Gram-negative bacterial membranes but requires optimization for clinical application.
Purpose of the Study:
- To develop novel analogues of the antimicrobial peptide Opis16a with enhanced membrane targeting and antibacterial efficacy.
- To investigate the structural modifications that improve Opis16a's activity, selectivity, and stability for burn wound infections.
- To evaluate the therapeutic potential of optimized Opis16a analogues in a relevant preclinical model.
Main Methods:
- Design and synthesis of four novel Opis16a analogues.
- Assessment of peptide-lipid interactions, conformational stability, and membrane permeabilization.
- Evaluation of antibacterial activity against Gram-negative bacteria and selectivity against human keratinocytes (HaCat cells).
- In vivo efficacy testing using a Galleria mellonella burn wound infection model.
Main Results:
- Optimized Opis16a analogues demonstrated improved membrane targeting and increased antibacterial potency.
- Enhanced peptide-lipid hydrogen bonding contributed to greater conformational stability and membrane insertion.
- Substitution of lysine with arginine residues in the C-terminus yielded consistent improvements in activity, selectivity, and serum stability.
- One analogue showed superior protection in a Galleria mellonella model against Enterobacter cloacae compared to native Opis16a.
Conclusions:
- Optimized Opis16a analogues represent a promising strategy for developing new treatments for Gram-negative burn wound infections.
- Structural modifications, particularly C-terminal arginine substitutions, enhance AMP efficacy and stability.
- These findings support the advancement of bactericidal AMPs for improved burn wound care and combating antimicrobial resistance.
