Journal Article

Antibacterial Properties and Efficacy of a Novel SPLUNC1-Derived Antimicrobial Peptide, α4-Short, in a Murine Model of Respiratory Infection

Di, Matthew E., Di, Y. Peter, Chen, Chen, Deslouches, Berthony, Jiang, Shasha

2019

Overview

The rise of superbugs underscores the urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs) have the ability to kill superbugs regardless of resistance to traditional antibiotics. However, AMPs often display a lack of efficacy in vivo. Sequence optimization and engineering are promising but may result in increased host toxicity. We report here the optimization of a novel AMP (α4-short) derived from the multifunctional respiratory protein SPLUNC1. The AMP α4-short demonstrated broad-spectrum activity against superbugs as well as in vivo efficacy in the P. aeruginosa pneumonia model. Further exploration for clinical development is warranted. Multidrug resistance (MDR) by bacterial pathogens constitutes a global health crisis, and resistance to treatment displayed by biofilm-associated infections (e.g., cystic fibrosis, surgical sites, and medical implants) only exacerbates a problem that is already difficult to overcome. Antimicrobial peptides (AMPs) are a promising class of therapeutics that may be useful in the battle against antibiotic resistance, although certain limitations have hindered their clinical development. The goal of this study was to examine the therapeutic potential of novel AMPs derived from the multifunctional respiratory host defense protein SPLUNC1. Using standard growth inhibition and antibiofilm assays, we demonstrated that a novel structurally optimized AMP, α4-short, was highly effective against the most common group of MDR bacteria while showing broad-spectrum bactericidal and antibiofilm activities. With negligible hemolysis and toxicity to white blood cells, the new peptide also demonstrated in vivo efficacy when delivered directly into the airway in a murine model of Pseudomonas aeruginosa -induced respiratory infection. The data warrant further exploration of SPLUNC1-derived AMPs with optimized structures to assess the potential application to difficult-to-cure biofilm-associated infections. IMPORTANCE The rise of superbugs underscores the urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs) have the ability to kill superbugs regardless of resistance to traditional antibiotics. However, AMPs often display a lack of efficacy in vivo. Sequence optimization and engineering are promising but may result in increased host toxicity. We report here the optimization of a novel AMP (α4-short) derived from the multifunctional respiratory protein SPLUNC1. The AMP α4-short demonstrated broad-spectrum activity against superbugs as well as in vivo efficacy in the P. aeruginosa pneumonia model. Further exploration for clinical development is warranted.

• Publisher: American Society for Microbiology
• Subject: airway infection / Amino acids / Animal models / Animals / Anti-Infective Agents - isolation & purification / Anti-Infective Agents - pharmacology / Anti-Infective Agents - therapeutic use / Antibiotic resistance / Antibiotics / Antimicrobial agents / Antimicrobial Cationic Peptides - isolation & purification / Antimicrobial Cationic Peptides - pharmacology / Antimicrobial Cationic Peptides - therapeutic use / Antimicrobial peptides / Bacteria / Bacteria - drug effects / biofilm / Biofilms / Biological Products - isolation & purification / Biological Products - pharmacology / Biological Products - therapeutic use / Blood / broad spectrum / Cystic fibrosis / Cytotoxicity / Disease Models, Animal / Drug resistance / Glycoproteins - metabolism / Kinetics / Leukocytes / Mice / Microbial Sensitivity Tests / Microbial Viability - drug effects / Multidrug resistance / Nosocomial infections / Optimization / Pathogens / Peptides / Phosphoproteins - metabolism / Pseudomonas Infections - drug therapy / Public health / Respiratory tract infection / Respiratory Tract Infections - drug therapy / SPLUNC1 / Staphylococcus infections / Therapeutics and Prevention / Toxicity / Treatment Outcome