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Kroneislová G, Macůrková A, Novotná Z, Ježek R, Lovecká P. Antimicrobial activity and properties of de novo design of short synthetic lipopeptides. Folia Microbiol (Praha) 2024; 69:445-457. [PMID: 38277095 PMCID: PMC11003925 DOI: 10.1007/s12223-024-01132-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 01/09/2024] [Indexed: 01/27/2024]
Abstract
The aim of this article is to introduce the topic of newly designed peptides as well as their biological activity. We designed nine encoded peptides composed of six amino acids. All these peptides were synthesized with C-terminal amidation. To investigate the importance of increased hydrophobicity at the amino end of the peptides, all of them were subsequently synthesized with palmitic or lithocholic acid at the N-terminus. Antimicrobial activity was tested on Gram-positive and Gram-negative bacteria and fungi. Cytotoxicity was measured on HepG2 and HEK 293 T cell cultures. Peptides bearing a hydrophobic group exhibited the best antimicrobial activity. Lipopeptides with palmitic or lithocholic acid (PAL or LCA peptides) at the N-terminus and with C-terminal amidation were highly active against Gram-positive bacteria, especially against strains of Staphylococcus aureus and Candida tropicalis. The LCA peptide SHP 1.3 with the sequence LCA-LVKRAG-NH2, had high efficiency on HepG2 human liver hepatocellular carcinoma cells (97%).
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Affiliation(s)
- Gabriela Kroneislová
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemical Technology Prague, Prague, Czech Republic
| | - Anna Macůrková
- Department of Diary, Fat and Cosmetics, Faculty of Food and Biochemical Technology, University of Chemical Technology Prague, Prague, Czech Republic
| | - Zuzana Novotná
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemical Technology Prague, Prague, Czech Republic
| | - Rudolf Ježek
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemical Technology Prague, Prague, Czech Republic
| | - Petra Lovecká
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemical Technology Prague, Prague, Czech Republic.
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van Gent ME, Schonkeren-Ravensbergen B, Achkif A, Beentjes D, Dolezal N, van Meijgaarden KE, Drijfhout JW, Nibbering PH. C-Terminal PEGylation Improves SAAP-148 Peptide's Immunomodulatory Activities. J Innate Immun 2023; 15:724-738. [PMID: 37725929 PMCID: PMC10601628 DOI: 10.1159/000534068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 08/30/2023] [Indexed: 09/21/2023] Open
Abstract
Synthetic antibacterial and anti-biofilm peptide (SAAP)-148 was developed to combat bacterial infections not effectively treatable with current antibiotics. SAAP-148 is highly effective against antimicrobial-resistant bacteria without inducing resistance; however, challenges for further development of SAAP-148 include its cytotoxicity and short circulation half-life. To circumvent these drawbacks, a library of SAAP-148 linked to polyethylene glycol (PEG) groups of various lengths was synthesized and screened for in vitro antibacterial activity and hemolytic activity. Results indicated that PEGylated SAAP-148 variants combine antibacterial activities with reduced hemolysis compared to SAAP-148. Interestingly, proinflammatory immunomodulatory activities of SAAP-148 were enhanced upon C-terminal PEGylation, with SAAP-148-PEG27 showing the most effect. SAAP-148-PEG27 enhanced SAAP-148's capacity to chemoattract human neutrophils and was able to more efficiently (re)direct M-CSF-induced monocyte-macrophage differentiation toward type 1 macrophages as opposed to SAAP-148. Furthermore, dendritic cells with a stronger mature expression profile were produced if monocytes were exposed to SAAP-148-PEG27 during monocyte-immature dendritic cell differentiation in comparison to SAAP-148. Parameters that influenced the immunomodulatory activities of the peptide-PEG conjugate include (i) the length of the PEG group, (ii) the position of PEG conjugation, and (iii) the peptide sequence. Together, these results indicate that SAAP-148-PEG27 is highly effective in redirecting monocyte-macrophage differentiation toward a proinflammatory phenotype and promoting monocyte-mature dendritic cell development. Therefore, SAAP-148-PEG27 may be a promising agent to modulate inadequate immune responses in case of tumors and chronically infected wounds.
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Affiliation(s)
- Miriam E. van Gent
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Asma Achkif
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Daan Beentjes
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Natasja Dolezal
- Department of Immunology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Jan Wouter Drijfhout
- Department of Immunology, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter H. Nibbering
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
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Silva ML, Carneiro MN, Cavalcante RMB, Guerrero JAP, Fontenelle ROS, Lorenzón EN, Cilli EM, Carneiro VA. K-aurein: A notable aurein 1.2-derived peptide that modulates Candida albicans filamentation and reduces biofilm biomass. Amino Acids 2023; 55:1003-1012. [PMID: 37442853 DOI: 10.1007/s00726-023-03288-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 05/25/2023] [Indexed: 07/15/2023]
Abstract
Candida albicans is considered one of the most important opportunistic fungi due to the large arsenal of virulence factors that help throughout the progress of the infection. In this sense, antimicrobial peptides (AMPs) appear as an alternative, with great antifungal action. Among these, aurein 1.2 has been widely explored, becoming the basis for the discovery of new AMPs, such as K-aurein (K-au). Thus, this study evaluated the anti-C. albicans potential of K-au against virulence factors, planktonic growth, and biofilm formation of clinical isolates. Firstly, K-au antifungal activity was determined by the microdilution method and time-kill curve. The inhibition of hydrolytic enzyme secretion (proteinase, phospholipase, and hemolysin) and germ tube formation was tested. Then, the antibiofilm potential of K-au was verified through biomass quantification and scanning electron microscopy (SEM). All tests were compared with the classical antifungal drug, amphotericin B (AmB). The outcomes showed fungicidal action of K-au at 62.50 µg mL-1 for all isolates, with a time of action around 150-180 min, determined by the time-kill curve. K-au-treated cells decreased by around 40% of the germinative tube compared to the control. Additionally, K-au inhibited the biofilm formation by more than 90% compared to AmB and the control group. SEM images show apparent cellular disaggregation without the formation of filamentous structures. Therefore, the findings suggest a promising anti-C. albicans effect of K-au due to its fungicidal activity against planktonic cells, or its ability to inhibit important virulence factors like germ tube and biofilm formation. Thus, this peptide could be explored as a useful compound against C. albicans-related infection.
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Affiliation(s)
- Maria Laína Silva
- Laboratory of Biofilms and Antimicrobial Agents (LaBAM), Faculty of Medicine, Federal University of Ceara-UFC, Sobral, 62048-280, Brazil
| | - Maria Nágila Carneiro
- Laboratory of Biofilms and Antimicrobial Agents (LaBAM), Faculty of Medicine, Federal University of Ceara-UFC, Sobral, 62048-280, Brazil
| | - Rafaela Mesquita Bastos Cavalcante
- Laboratory of Biofilms and Antimicrobial Agents (LaBAM), Faculty of Medicine, Federal University of Ceara-UFC, Sobral, 62048-280, Brazil
| | - Jesús Alberto Pérez Guerrero
- Laboratory of Biofilms and Antimicrobial Agents (LaBAM), Faculty of Medicine, Federal University of Ceara-UFC, Sobral, 62048-280, Brazil
| | | | | | - Eduardo Maffud Cilli
- Department of Biochemistry and Organic Chemistry, Estadual University of São Paulo-UNESP, Araraquara, 14800-900, Brazil
| | - Victor Alves Carneiro
- Laboratory of Biofilms and Antimicrobial Agents (LaBAM), Faculty of Medicine, Federal University of Ceara-UFC, Sobral, 62048-280, Brazil.
- Center for Bioprospecting and Applied Molecular Experimentation (NUBEM), University Center INTA-UNINTA, Sobral, 62050-100, Brazil.
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Deciphering Structure-Function Relationship Unveils Salt-Resistant Mode of Action of a Potent MRSA-Inhibiting Antimicrobial Peptide, RR14. J Bacteriol 2022; 204:e0031222. [PMID: 36377870 PMCID: PMC9765028 DOI: 10.1128/jb.00312-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Multidrug-resistant (MDR) bacteria lead to considerable morbidity and mortality, threatening public health worldwide. In particular, infections of methicillin-resistant Staphylococcus aureus (MRSA) in hospital and community settings are becoming a serious health problem. Antimicrobial peptides (AMPs) are considered novel therapeutic targets against MDR bacteria. However, salt sensitivity reduces the bactericidal potency of AMPs, posing a major obstacle for their development as antibiotics. Thus, the design and development of salt-insensitive peptides with potent antibacterial activity is imperative. Here, we employed biochemical and biophysical examinations coupled with molecular modeling to systematically investigate the structure-function relationship of a novel salt-insensitive AMP, RR14. The secondary structure of RR14 was characterized as an apparent α-helix, a structure that confers strong membrane-permeabilizing ability targeting bacterial-mimetic membranes. Additionally, the bioactive structure of RR14 was determined in complex with dodecylphosphocholine (DPC) micelles, where it possesses a central α-helical segment comprising residues R4 to K13 (R4-K13). RR14 was observed to orient itself into the DPC micelle with its N terminus and the α-helical segment (I5-R10) buried inside the micelles, which is essential for membrane permeabilization and bactericidal activity. Moreover, the specific and featured arrangement of positively charged residues of RR14 on its amphipathic helical conformation has great potential to render its strong salt resistance ability. Our study explored the structure-function relationship of RR14, explaining its possible mode of action against MRSA and other microbes. The insights obtained are of great applicability for the development of new antibacterial agents. IMPORTANCE Many antimicrobial peptides have been observed to become inactive in the presence of high salt concentrations. To further develop new and novel AMPs with potent bactericidal activity and salt insensitivity, understanding the structural basis for salt resistance is important. Here, we employed biochemical and biophysical examinations to systematically investigate the structure-function relationship of a novel salt-insensitive AMP, RR14. RR14 was observed to orient itself into DPC micelles with the N terminus and the α-helical segment (I5-R10) buried inside the micelles, which is essential for membrane permeabilization and bactericidal activity. Moreover, the specific and featured arrangement of cationic residues of RR14 on its amphipathic helical conformation renders its strong salt resistance ability. The insights obtained are of great applicability for developing new antibacterial agents.
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Kakar A, Sastré-Velásquez LE, Hess M, Galgóczy L, Papp C, Holzknecht J, Romanelli A, Váradi G, Malanovic N, Marx F. The Membrane Activity of the Amphibian Temporin B Peptide Analog TB_KKG6K Sheds Light on the Mechanism That Kills Candida albicans. mSphere 2022; 7:e0029022. [PMID: 35972132 PMCID: PMC9599520 DOI: 10.1128/msphere.00290-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 07/27/2022] [Indexed: 11/25/2022] Open
Abstract
Temporin B (TB) is a 13-amino-acid-long, cationic peptide secreted by the granular glands of the European frog Rana temporaria. We recently showed that the modified TB peptide analog TB_KKG6K rapidly killed planktonic and sessile Candida albicans at low micromolar concentrations and was neither hemolytic nor cytotoxic to mammalian cells in vitro. The present study aimed to shed light into its mechanism of action, with a focus on its fungal cell membrane activity. We utilized different fluorescent dyes to prove that it rapidly induces membrane depolarization and permeabilization. Studies on model membrane systems revealed that the TB analog undergoes hydrophobic and electrostatic membrane interactions, showing a preference for anionic lipids, and identified phosphatidylinositol and cardiolipin as possible peptide targets. Fluorescence microscopy using fluorescein isothiocyanate-labeled TB_KKG6K in the presence of the lipophilic dye FM4-64 indicated that the peptide compromises membrane integrity and rapidly enters C. albicans cells in an energy-independent manner. Peptide-treated cells analyzed by cryo-based electron microscopy exhibited no signs of cell lysis; however, subcellular structures had disintegrated, suggesting that intracellular activity may form part of the killing mechanism of the peptide. Taken together, this study proved that TB_KKG6K compromises C. albicans membrane function, which explains the previously observed rapid, fungicidal mode of action and supports its great potential as a future anti-Candida therapeutic. IMPORTANCE Fungal infections with the opportunistic human pathogen C. albicans are associated with high mortality rates in immunocompromised patients. This is partly due to the yeast's ability to rapidly develop resistance toward currently available antifungals. Small, cationic, membrane-active peptides are promising compounds to fight against resistance development, as many of them effectuate rapid fungal cell death. This fast killing is believed to hamper the development of resistance, as the fungi do not have sufficient time to adapt to the antifungal compound. We previously reported that the synthetic variant of the amphibian TB peptide, TB_KKG6K, rapidly kills C. albicans. In the current study, the mechanism of action of the TB analog was investigated. We show that this TB analog is membrane-active and impairs cell membrane function, highlighting its potential to be developed as an attractive alternative anti-C. albicans therapeutic that may hinder the development of resistance.
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Affiliation(s)
- Anant Kakar
- Biocenter, Institute of Molecular Biology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Michael Hess
- Institute for Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - László Galgóczy
- Department of Biotechnology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- Institute of Biochemistry, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Csaba Papp
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Jeanett Holzknecht
- Biocenter, Institute of Molecular Biology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Györgyi Váradi
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Nermina Malanovic
- Institute of Molecular Biosciences, Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Florentine Marx
- Biocenter, Institute of Molecular Biology, Medical University of Innsbruck, Innsbruck, Austria
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