Trematocine-derived antimicrobial peptides from the Antarctic fish Trematomus bernacchaii: potent antibacterial agents against ESKAPE pathogens

• Published in: Frontiers in Microbiology
• Main Authors: Damiano Squitieri, Federica Massaro, Monica Mollica Graziano, Stefano Borocci, Margherita Cacaci, Maura Di Vito, Fernando Porcelli, Roberto Rosato, Francesca Ceccacci, Maurizio Sanguinetti, Francesco Buonocore, Francesca Bugli
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2024
• Subjects: antimicrobial peptides; antimicrobial resistance; ESKAPE pathogens; membranolytic agents; multi-drug resistant bacteria; Microbiology; QR1-502; Antarctic; The Antarctic; Antarc*
• Online Access: https://doi.org/10.3389/fmicb.2024.1447301; https://doaj.org/article/0e5eae83f95c4afcbd84d0af0983bca0

IntroductionThis study investigated the interaction with membrane mimetic systems (LUVs), bacterial membranes, the CD spectra, and the bactericidal activity of two designed trematocine mutants, named Trem-HK and Trem-HSK. Mutants were constructed from the scaffold of Trematocine (Trem), a natural 22-amino acid AMP from the Antarctic fish Trematomus bernacchii, aiming to increase their positive charge.MethodsThe selectivity of the designed AMPs towards bacterial membranes was improved compared to Trematocine, verified by their interaction with different LUVs and their membranolytic activity. Additionally, their α-helical conformation was not influenced by the amino acid substitutions. Our findings revealed a significant enhancement in antibacterial efficacy against ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae family) pathogens for both Trem-HK and Trem-HSK.ResultsFirstly, we showed that the selectivity of the two new designed AMPs towards bacterial membranes was greatly improved compared to Trematocine, verifying their interaction with different LUVs and their membranolytic activity. We determined that their α-helical conformation was not influenced by the amino acid substitutions. We characterized the tested bacterial collection for resistance traits to different classes of antibiotics. The minimum inhibitory and bactericidal concentration (MIC and MBC) values of the ESKAPE collection were reduced by up to 80% compared to Trematocine. The bactericidal concentrations of Trematocine mutants showed important membranolytic action, evident by scanning electron microscopy, on all tested species. We further evaluated the cytotoxicity and hemolytic activity of the mutants. At 2.5 μM concentration, both mutants demonstrated low cytotoxicity and hemolysis, indicating selectivity towards bacterial cells. However, these effects increased at higher concentrations.DiscussionAssessment of in vivo toxicity using the Galleria ...