The mechanism of action of pepR, a viral-derived peptide, against Staphylococcus aureus biofilms

Journal Article · Fri May 24 00:00:00 EDT 2019 · Journal of Antimicrobial Chemotherapy

DOI:https://doi.org/10.1093/jac/dkz223· OSTI ID:1564567

Pinto, Sandra N. ^[1]; Dias, Susana A. ^[2]; Cruz, Ana F. ^[2]; Mil-Homens, Dalila ^[3]; Fernandes, Fabio ^[1]; Valle, Javier ^[4]; Andreu, David ^[4]; Prieto, Manuel ^[1]; Castanho, Miguel A. R. B. ^[2]; Coutinho, Ana ^[5]; Veiga, Ana Salomé ^[2]

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1. Centro de Química-Física Molecular e IN, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais Lisboa, Portugal, iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais Lisboa, Portugal
2. Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, Lisboa, Portugal
3. iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais Lisboa, Portugal
4. Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona Biomedical Research Park, Barcelona, Spain
5. Centro de Química-Física Molecular e IN, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais Lisboa, Portugal, iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais Lisboa, Portugal, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande Lisboa, Portugal

Abstract Objectives To investigate the mechanism of action at the molecular level of pepR, a multifunctional peptide derived from the Dengue virus capsid protein, against Staphylococcus aureus biofilms. Methods Biofilm mass, metabolic activity and viability were quantified using conventional microbiology techniques, while fluorescence imaging methods, including a real-time calcein release assay, were employed to investigate the kinetics of pepR activity at different biofilm depths. Results Using flow cytometry-based assays, we showed that pepR is able to prevent staphylococcal biofilm formation due to a fast killing of planktonic bacteria, which in turn resulted from a peptide-induced increase in the permeability of the bacterial membranes. The activity of pepR against pre-formed biofilms was evaluated through the application of a quantitative live/dead confocal laser scanning microscopy (CLSM) assay. The results show that the bactericidal activity of pepR on pre-formed biofilms is dose and depth dependent. A CLSM-based assay of calcein release from biofilm-embedded bacteria was further developed to indirectly assess the diffusion and membrane permeabilization properties of pepR throughout the biofilm. A slower diffusion and delayed activity of the peptide at deeper layers of the biofilm were quantified. Conclusions Overall, our results show that the activity of pepR on pre-formed biofilms is controlled by its diffusion along the biofilm layers, an effect that can be counteracted by an additional administration of peptide. Our study sheds new light on the antibiofilm mechanism of action of antimicrobial peptides, particularly the importance of their diffusion properties through the biofilm matrix on their activity.

• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Nuclear Fuel Cycle and Supply Chain
• Grant/Contract Number: SFRH/BPD/92409/2013; PD/BD/114425/2016; PD/BD/136866/2018; SFRH/BPD/91831/2012; IF/00803/2012; IF/00386/2015
• OSTI ID: 1564567
• Journal Information: Journal of Antimicrobial Chemotherapy, Journal Name: Journal of Antimicrobial Chemotherapy Vol. 74 Journal Issue: 9; ISSN 0305-7453
• Publisher: Oxford University Press
• Country of Publication: United Kingdom
• Language: English