Anti-<i>Staphylococcus aureus</i> Activity and Structural Characterization of Rationally Designed Peptides

<b>Background/Objectives</b>: Microbial infections represent a significant threat to public health due to the emergence and spread of antimicrobial resistance. Adjunctive and alternative therapeutic strategies are explored to tackle this issue, including the use of natural or synthetic a...

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Main Authors: Lorenza Artesani, Mariana Gallo, Laura Giovati, Francesca Maria Bisignano, Elena Ferrari, Lara M. Castronovo, Stefania Conti, Francesco Santoro, Thelma A. Pertinhez, Tecla Ciociola
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Antibiotics
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Online Access:https://www.mdpi.com/2079-6382/14/5/437
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author Lorenza Artesani
Mariana Gallo
Laura Giovati
Francesca Maria Bisignano
Elena Ferrari
Lara M. Castronovo
Stefania Conti
Francesco Santoro
Thelma A. Pertinhez
Tecla Ciociola
author_facet Lorenza Artesani
Mariana Gallo
Laura Giovati
Francesca Maria Bisignano
Elena Ferrari
Lara M. Castronovo
Stefania Conti
Francesco Santoro
Thelma A. Pertinhez
Tecla Ciociola
author_sort Lorenza Artesani
collection DOAJ
description <b>Background/Objectives</b>: Microbial infections represent a significant threat to public health due to the emergence and spread of antimicrobial resistance. Adjunctive and alternative therapeutic strategies are explored to tackle this issue, including the use of natural or synthetic antimicrobial peptides. Previous research showed that antibody-derived peptides possess antimicrobial, antiviral, and immunomodulatory properties. This study aimed to characterize newly designed antibody-derived peptides and evaluate their effectiveness against representative strains of <i>Staphylococcus aureus</i>, including drug-resistant isolates. <b>Methods</b>: Colony-forming unit assays and confocal microscopy studies were performed to evaluate peptide activity against planktonic microbial cells. Cytotoxicity tests were performed on THP-1 human monocytic cells. Circular dichroism (CD) and nuclear magnetic resonance (NMR) were employed for the conformational characterization of peptides. <b>Results</b>: The half-maximal effective concentrations of the peptides against bacterial reference strains and drug-resistant isolates ranged from 0.17 to 18.05 µM, while cytotoxic effects were not observed against mammalian cells. A killing kinetics analysis and observation by confocal microscopy of the interaction between peptides and bacteria suggested a mechanism of action involving membrane perturbation. CD studies showed that all peptides predominantly exhibit a random coil arrangement in aqueous solution. NMR spectroscopy revealed that the most active peptide adopts a helical conformation in the presence of membrane mimetics. <b>Conclusions</b>: The structural characterization and evaluation of the newly designed peptides’ antimicrobial activity may lead to the selection of a candidate to be further studied to develop an alternative treatment against microbial infections caused by drug-resistant strains.
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spelling doaj-art-cc2c83497df5424aa43ea957ea63bcbc2025-08-20T01:56:20ZengMDPI AGAntibiotics2079-63822025-04-0114543710.3390/antibiotics14050437Anti-<i>Staphylococcus aureus</i> Activity and Structural Characterization of Rationally Designed PeptidesLorenza Artesani0Mariana Gallo1Laura Giovati2Francesca Maria Bisignano3Elena Ferrari4Lara M. Castronovo5Stefania Conti6Francesco Santoro7Thelma A. Pertinhez8Tecla Ciociola9Laboratory of Microbiology and Virology, Department of Medicine and Surgery, University of Parma, 43125 Parma, ItalyLaboratory of Biochemistry and Metabolomics, Department of Medicine and Surgery, University of Parma, 43125 Parma, ItalyLaboratory of Microbiology and Virology, Department of Medicine and Surgery, University of Parma, 43125 Parma, ItalyLaboratory of Microbiology and Virology, Department of Medicine and Surgery, University of Parma, 43125 Parma, ItalyLaboratory of Biochemistry and Metabolomics, Department of Medicine and Surgery, University of Parma, 43125 Parma, ItalyLaboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, 53100 Siena, ItalyLaboratory of Microbiology and Virology, Department of Medicine and Surgery, University of Parma, 43125 Parma, ItalyLaboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, 53100 Siena, ItalyLaboratory of Biochemistry and Metabolomics, Department of Medicine and Surgery, University of Parma, 43125 Parma, ItalyLaboratory of Microbiology and Virology, Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy<b>Background/Objectives</b>: Microbial infections represent a significant threat to public health due to the emergence and spread of antimicrobial resistance. Adjunctive and alternative therapeutic strategies are explored to tackle this issue, including the use of natural or synthetic antimicrobial peptides. Previous research showed that antibody-derived peptides possess antimicrobial, antiviral, and immunomodulatory properties. This study aimed to characterize newly designed antibody-derived peptides and evaluate their effectiveness against representative strains of <i>Staphylococcus aureus</i>, including drug-resistant isolates. <b>Methods</b>: Colony-forming unit assays and confocal microscopy studies were performed to evaluate peptide activity against planktonic microbial cells. Cytotoxicity tests were performed on THP-1 human monocytic cells. Circular dichroism (CD) and nuclear magnetic resonance (NMR) were employed for the conformational characterization of peptides. <b>Results</b>: The half-maximal effective concentrations of the peptides against bacterial reference strains and drug-resistant isolates ranged from 0.17 to 18.05 µM, while cytotoxic effects were not observed against mammalian cells. A killing kinetics analysis and observation by confocal microscopy of the interaction between peptides and bacteria suggested a mechanism of action involving membrane perturbation. CD studies showed that all peptides predominantly exhibit a random coil arrangement in aqueous solution. NMR spectroscopy revealed that the most active peptide adopts a helical conformation in the presence of membrane mimetics. <b>Conclusions</b>: The structural characterization and evaluation of the newly designed peptides’ antimicrobial activity may lead to the selection of a candidate to be further studied to develop an alternative treatment against microbial infections caused by drug-resistant strains.https://www.mdpi.com/2079-6382/14/5/437antimicrobial peptides<i>Staphylococcus aureus</i>MRSAVRSAstructural characterizationcircular dichroism
spellingShingle Lorenza Artesani
Mariana Gallo
Laura Giovati
Francesca Maria Bisignano
Elena Ferrari
Lara M. Castronovo
Stefania Conti
Francesco Santoro
Thelma A. Pertinhez
Tecla Ciociola
Anti-<i>Staphylococcus aureus</i> Activity and Structural Characterization of Rationally Designed Peptides
Antibiotics
antimicrobial peptides
<i>Staphylococcus aureus</i>
MRSA
VRSA
structural characterization
circular dichroism
title Anti-<i>Staphylococcus aureus</i> Activity and Structural Characterization of Rationally Designed Peptides
title_full Anti-<i>Staphylococcus aureus</i> Activity and Structural Characterization of Rationally Designed Peptides
title_fullStr Anti-<i>Staphylococcus aureus</i> Activity and Structural Characterization of Rationally Designed Peptides
title_full_unstemmed Anti-<i>Staphylococcus aureus</i> Activity and Structural Characterization of Rationally Designed Peptides
title_short Anti-<i>Staphylococcus aureus</i> Activity and Structural Characterization of Rationally Designed Peptides
title_sort anti i staphylococcus aureus i activity and structural characterization of rationally designed peptides
topic antimicrobial peptides
<i>Staphylococcus aureus</i>
MRSA
VRSA
structural characterization
circular dichroism
url https://www.mdpi.com/2079-6382/14/5/437
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