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Oludiran A, Malik A, Zourou AC, Wu Y, Gross SP, Siryapon A, Poudel A, Alleyne K, Adams S, Courson DS, Cotten ML, Purcell EB. Host-defense piscidin peptides as antibiotic adjuvants against Clostridioides difficile. PLoS One 2024; 19:e0295627. [PMID: 38252641 PMCID: PMC10802969 DOI: 10.1371/journal.pone.0295627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 11/26/2023] [Indexed: 01/24/2024] Open
Abstract
The spore-forming intestinal pathogen Clostridioides difficile causes multidrug resistant infection with a high rate of recurrence after treatment. Piscidins 1 (p1) and 3 (p3), cationic host defense peptides with micromolar cytotoxicity against C. difficile, sensitize C. difficile to clinically relevant antibiotics tested at sublethal concentrations. Both peptides bind to Cu2+ using an amino terminal copper and nickel binding motif. Here, we investigate the two peptides in the apo and holo states as antibiotic adjuvants against an epidemic strain of C. difficile. We find that the presence of the peptides leads to lower doses of metronidazole, vancomycin, and fidaxomicin to kill C. difficile. The activity of metronidazole, which targets DNA, is enhanced by a factor of 32 when combined with p3, previously shown to bind and condense DNA. Conversely, the activity of vancomycin, which acts at bacterial cell walls, is enhanced 64-fold when combined with membrane-active p1-Cu2+. As shown through microscopy monitoring the permeabilization of membranes of C. difficile cells and vesicle mimics of their membranes, the adjuvant effect of p1 and p3 in the apo and holo states is consistent with a mechanism of action where the peptides enable greater antibiotic penetration through the cell membrane to increase their bioavailability. The variations in effects obtained with the different forms of the peptides reveal that while all piscidins generally sensitize C. difficile to antibiotics, co-treatments can be optimized in accordance with the underlying mechanism of action of the peptides and antibiotics. Overall, this study highlights the potential of antimicrobial peptides as antibiotic adjuvants to increase the lethality of currently approved antibiotic dosages, reducing the risk of incomplete treatments and ensuing drug resistance.
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Affiliation(s)
- Adenrele Oludiran
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - Areej Malik
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
- Biomedical Sciences Program, Old Dominion University, Norfolk, Virginia, United States of America
| | - Andriana C. Zourou
- Department of Applied Science, William & Mary, Williamsburg, Virginia, United States of America
| | - Yonghan Wu
- Irvine Department of Physics and Astronomy, University of California, Los Angeles, California, United States of America
| | - Steven P. Gross
- Ivrine Department of Developmental and Cell Biology, University of California, Los Angeles, California, United States of America
| | - Albert Siryapon
- Irvine Department of Physics and Astronomy, University of California, Los Angeles, California, United States of America
| | - Asia Poudel
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - Kwincy Alleyne
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - Savion Adams
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - David S. Courson
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - Myriam L. Cotten
- Department of Applied Science, William & Mary, Williamsburg, Virginia, United States of America
| | - Erin B. Purcell
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
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2
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Liu F, Greenwood AI, Xiong Y, Miceli RT, Fu R, Anderson KW, McCallum SA, Mihailescu M, Gross R, Cotten ML. Host Defense Peptide Piscidin and Yeast-Derived Glycolipid Exhibit Synergistic Antimicrobial Action through Concerted Interactions with Membranes. JACS AU 2023; 3:3345-3365. [PMID: 38155643 PMCID: PMC10751773 DOI: 10.1021/jacsau.3c00506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 09/25/2023] [Accepted: 09/29/2023] [Indexed: 12/30/2023]
Abstract
Developing new antimicrobials as alternatives to conventional antibiotics has become an urgent race to eradicate drug-resistant bacteria and to save human lives. Conventionally, antimicrobial molecules are studied independently even though they can be cosecreted in vivo. In this research, we investigate two classes of naturally derived antimicrobials: sophorolipid (SL) esters as modified yeast-derived glycolipid biosurfactants that feature high biocompatibility and low production cost; piscidins, which are host defense peptides (HDPs) from fish. While HDPs such as piscidins target the membrane of pathogens, and thus result in low incidence of resistance, SLs are not well understood on a mechanistic level. Here, we demonstrate that combining SL-hexyl ester (SL-HE) with subinhibitory concentration of piscidins 1 (P1) and 3 (P3) stimulates strong antimicrobial synergy, potentiating a promising therapeutic window. Permeabilization assays and biophysical studies employing circular dichroism, NMR, mass spectrometry, and X-ray diffraction are performed to investigate the mechanism underlying this powerful synergy. We reveal four key mechanistic features underlying the synergistic action: (1) P1/3 binds to SL-HE aggregates, becoming α-helical; (2) piscidin-glycolipid assemblies synergistically accumulate on membranes; (3) SL-HE used alone or bound to P1/3 associates with phospholipid bilayers where it induces defects; (4) piscidin-glycolipid complexes disrupt the bilayer structure more dramatically and differently than either compound alone, with phase separation occurring when both agents are present. Overall, dramatic enhancement in antimicrobial activity is associated with the use of two membrane-active agents, with the glycolipid playing the roles of prefolding the peptide, coordinating the delivery of both agents to bacterial surfaces, recruiting the peptide to the pathogenic membranes, and supporting membrane disruption by the peptide. Given that SLs are ubiquitously and safely used in consumer products, the SL/peptide formulation engineered and mechanistically characterized in this study could represent fertile ground to develop novel synergistic agents against drug-resistant bacteria.
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Affiliation(s)
- Fei Liu
- Department
of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Alexander I. Greenwood
- Department
of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
| | - Yawei Xiong
- Department
of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
| | - Rebecca T. Miceli
- Department
of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Riqiang Fu
- Center
of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Kyle W. Anderson
- National
Institute of Standards and Technology, Rockville, Maryland 20850, United States
| | - Scott A. McCallum
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Mihaela Mihailescu
- Institute
for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
| | - Richard Gross
- Department
of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Myriam L. Cotten
- Department
of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
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3
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Lane BJ, Pliotas C. Approaches for the modulation of mechanosensitive MscL channel pores. Front Chem 2023; 11:1162412. [PMID: 37021145 PMCID: PMC10069478 DOI: 10.3389/fchem.2023.1162412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 03/03/2023] [Indexed: 03/17/2023] Open
Abstract
MscL was the first mechanosensitive ion channel identified in bacteria. The channel opens its large pore when the turgor pressure of the cytoplasm increases close to the lytic limit of the cellular membrane. Despite their ubiquity across organisms, their importance in biological processes, and the likelihood that they are one of the oldest mechanisms of sensory activation in cells, the exact molecular mechanism by which these channels sense changes in lateral tension is not fully understood. Modulation of the channel has been key to understanding important aspects of the structure and function of MscL, but a lack of molecular triggers of these channels hindered early developments in the field. Initial attempts to activate mechanosensitive channels and stabilize functionally relevant expanded or open states relied on mutations and associated post-translational modifications that were often cysteine reactive. These sulfhydryl reagents positioned at key residues have allowed the engineering of MscL channels for biotechnological purposes. Other studies have modulated MscL by altering membrane properties, such as lipid composition and physical properties. More recently, a variety of structurally distinct agonists have been shown bind to MscL directly, close to a transmembrane pocket that has been shown to have an important role in channel mechanical gating. These agonists have the potential to be developed further into antimicrobial therapies that target MscL, by considering the structural landscape and properties of these pockets.
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Affiliation(s)
- Benjamin J. Lane
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Christos Pliotas
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester, United Kingdom
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom
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4
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Bischetti M, Alaimo N, Nardelli F, Punzi P, Amariei C, Ingenito R, Musco G, Gallo M, Cicero DO. Structural insights on the selective interaction of the histidine-rich piscidin antimicrobial peptide Of-Pis1 with membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184080. [PMID: 36328080 DOI: 10.1016/j.bbamem.2022.184080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 09/26/2022] [Accepted: 10/20/2022] [Indexed: 11/08/2022]
Abstract
Of-Pis1 is a potent piscidin antimicrobial peptide (AMP), recently isolated from rock bream (Oplegnathus fasciatus). This rich in histidines and glycines 24-amino acid peptide displays high and broad antimicrobial activity and no significant hemolytic toxicity against human erythrocytes, suggesting low toxicity. To better understand the mechanism of action of Of-Pis1 and its potential selectivity, using NMR and CD spectroscopies, we studied the interaction with eukaryotic and procaryotic membranes and membrane models. Anionic sodium dodecyl sulfate (SDS) and lipopolysaccharide (LPS) micelles were used to mimic procaryotic membranes, while zwitterionic dodecyl phosphocholine (DPC) was used as eukaryotic membrane surrogate. In an aqueous environment, Of-Pis1 adopts a flexible random coil conformation. In DPC and SDS instead, the N-terminal region of Of-Pis1 forms an amphipathic α-helix with the non-polar face in close contact with the micelles. Slower solvent exchange and higher pKas of the histidine residues in SDS than in DPC suggest that Of-Pis1 interacts more tightly with SDS. Of-Pis1 also binds tightly and structurally perturbs LPS micelles. Of-Pis1 interacts with both Escherichia coli and mammalian cell membranes, but only in the presence of Escherichia coli membranes it populates the helical conformation. Furthermore, ligand-based NMR experiments support a tighter and more specific interaction with bacterial than with eukaryotic membranes. Overall, these data clearly show the selective interaction of this broadly active AMP with bacterial over eukaryotic membranes. The conformational information is discussed in terms of Of-Pis1 amino acid sequence and composition to provide insights useful to design more potent and selective AMPs.
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Affiliation(s)
- Martina Bischetti
- Department of Chemical Science and Technology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Nadine Alaimo
- Structural Biology and Computational Chemistry, IRBM SpA, Via Pontina Km 30 600, 00 071 Pomezia, Rome, Italy
| | - Francesca Nardelli
- Biomolecular NMR Laboratory, I.R.C.C.S. Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy
| | - Pasqualina Punzi
- Peptides Chemistry Unit, IRBM SpA, Via Pontina Km 30 600, 00 071 Pomezia, Rome, Italy
| | - Cristi Amariei
- Department of Chemical Science and Technology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Raffaele Ingenito
- Peptides Chemistry Unit, IRBM SpA, Via Pontina Km 30 600, 00 071 Pomezia, Rome, Italy
| | - Giovana Musco
- Biomolecular NMR Laboratory, I.R.C.C.S. Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy
| | - Mariana Gallo
- Structural Biology and Computational Chemistry, IRBM SpA, Via Pontina Km 30 600, 00 071 Pomezia, Rome, Italy.
| | - Daniel Oscar Cicero
- Department of Chemical Science and Technology, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133 Rome, Italy
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Flegler VJ, Rasmussen T, Böttcher B. How Functional Lipids Affect the Structure and Gating of Mechanosensitive MscS-like Channels. Int J Mol Sci 2022; 23:ijms232315071. [PMID: 36499396 PMCID: PMC9739000 DOI: 10.3390/ijms232315071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/04/2022] Open
Abstract
The ability to cope with and adapt to changes in the environment is essential for all organisms. Osmotic pressure is a universal threat when environmental changes result in an imbalance of osmolytes inside and outside the cell which causes a deviation from the normal turgor. Cells have developed a potent system to deal with this stress in the form of mechanosensitive ion channels. Channel opening releases solutes from the cell and relieves the stress immediately. In bacteria, these channels directly sense the increased membrane tension caused by the enhanced turgor levels upon hypoosmotic shock. The mechanosensitive channel of small conductance, MscS, from Escherichia coli is one of the most extensively studied examples of mechanically stimulated channels. Different conformational states of this channel were obtained in various detergents and membrane mimetics, highlighting an intimate connection between the channel and its lipidic environment. Associated lipids occupy distinct locations and determine the conformational states of MscS. Not all these features are preserved in the larger MscS-like homologues. Recent structures of homologues from bacteria and plants identify common features and differences. This review discusses the current structural and functional models for MscS opening, as well as the influence of certain membrane characteristics on gating.
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6
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Sidarta M, Baruah L, Wenzel M. Roles of Bacterial Mechanosensitive Channels in Infection and Antibiotic Susceptibility. Pharmaceuticals (Basel) 2022; 15:ph15070770. [PMID: 35890069 PMCID: PMC9322971 DOI: 10.3390/ph15070770] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/17/2022] [Accepted: 06/19/2022] [Indexed: 02/01/2023] Open
Abstract
Bacteria accumulate osmolytes to prevent cell dehydration during hyperosmotic stress. A sudden change to a hypotonic environment leads to a rapid water influx, causing swelling of the protoplast. To prevent cell lysis through osmotic bursting, mechanosensitive channels detect changes in turgor pressure and act as emergency-release valves for the ions and osmolytes, restoring the osmotic balance. This adaptation mechanism is well-characterized with respect to the osmotic challenges bacteria face in environments such as soil or an aquatic habitat. However, mechanosensitive channels also play a role during infection, e.g., during host colonization or release into environmental reservoirs. Moreover, recent studies have proposed roles for mechanosensitive channels as determinants of antibiotic susceptibility. Interestingly, some studies suggest that they serve as entry gates for antimicrobials into cells, enhancing antibiotic efficiency, while others propose that they play a role in antibiotic-stress adaptation, reducing susceptibility to certain antimicrobials. These findings suggest different facets regarding the relevance of mechanosensitive channels during infection and antibiotic exposure as well as illustrate that they may be interesting targets for antibacterial chemotherapy. Here, we summarize the recent findings on the relevance of mechanosensitive channels for bacterial infections, including transitioning between host and environment, virulence, and susceptibility to antimicrobials, and discuss their potential as antibacterial drug targets.
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7
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Abstract
Copper ions bind to biomolecules (e.g., peptides and proteins) playing an essential role in many biological and physiological pathways in the human body. The resulting complexes may contribute to the initiation of neurodegenerative diseases, cancer, and bacterial and viral diseases, or act as therapeutics. Some compounds can chemically damage biological macromolecules and initiate the development of pathogenic states. Conversely, a number of these compounds may have antibacterial, antiviral, and even anticancer properties. One of the most significant current discussions in Cu biochemistry relates to the mechanisms of the positive and negative actions of Cu ions based on the generation of reactive oxygen species, including radicals that can interact with DNA molecules. This review aims to analyze various peptide–copper complexes and the mechanism of their action.
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8
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Copper-binding anticancer peptides from the piscidin family: an expanded mechanism that encompasses physical and chemical bilayer disruption. Sci Rep 2021; 11:12620. [PMID: 34135370 PMCID: PMC8208971 DOI: 10.1038/s41598-021-91670-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 05/21/2021] [Indexed: 12/11/2022] Open
Abstract
In the search for novel broad-spectrum therapeutics to fight chronic infections, inflammation, and cancer, host defense peptides (HDPs) have garnered increasing interest. Characterizing their biologically-active conformations and minimum motifs for function represents a requisite step to developing them into efficacious and safe therapeutics. Here, we demonstrate that metallating HDPs with Cu2+ is an effective chemical strategy to improve their cytotoxicity on cancer cells. Mechanistically, we find that prepared as Cu2+-complexes, the peptides not only physically but also chemically damage lipid membranes. Our testing ground features piscidins 1 and 3 (P1/3), two amphipathic, histidine-rich, membrane-interacting, and cell-penetrating HDPs that are α-helical bound to membranes. To investigate their membrane location, permeabilization effects, and lipid-oxidation capability, we employ neutron reflectometry, impedance spectroscopy, neutron diffraction, and UV spectroscopy. While P1-apo is more potent than P3-apo, metallation boosts their cytotoxicities by up to two- and seven-fold, respectively. Remarkably, P3-Cu2+ is particularly effective at inserting in bilayers, causing water crevices in the hydrocarbon region and placing Cu2+ near the double bonds of the acyl chains, as needed to oxidize them. This study points at a new paradigm where complexing HDPs with Cu2+ to expand their mechanistic reach could be explored to design more potent peptide-based anticancer therapeutics.
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9
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Fu R, Rooney MT, Zhang R, Cotten ML. Coordination of Redox Ions within a Membrane-Binding Peptide: A Tale of Aromatic Rings. J Phys Chem Lett 2021; 12:4392-4399. [PMID: 33939920 DOI: 10.1021/acs.jpclett.1c00636] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The amino-terminal-copper-and-nickel-binding (ATCUN) motif, a tripeptide sequence ending with a histidine, confers important functions to proteins and peptides. Few high-resolution studies have been performed on the ATCUN motifs of membrane-associated proteins and peptides, limiting our understanding of how they stabilize Cu2+/Ni2+ in membranes. Here, we leverage solid-state NMR to investigate metal-binding to piscidin-1 (P1), a host-defense peptide featuring F1F2H3 as its ATCUN motif. Bound to redox ions, P1 chemically and physically damages pathogenic cell membranes. We design 13C/15N correlation experiments to detect and assign the deprotonated nitrogens produced and/or shifted by Ni2+-binding. Occupying multiple chemical states in P1-apo, H3 and the neighboring H4 respond to metalation by populating only the τ-tautomer. H3, as a proximal histidine, directly coordinates the metal, compared to the distal H4. Density functional theory calculations reflect this noncanonical arrangement and point toward cation-π interactions between the F1/F2/H4 aromatic rings and metal. These structural findings, which are relevant to other ATCUN-containing membrane peptides, could help design new therapeutics and materials for use in the areas of drug-resistant bacteria, neurological disorders, and biomedical imaging.
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Affiliation(s)
- Riqiang Fu
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Mary T Rooney
- Department of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
| | - Rongfu Zhang
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Myriam L Cotten
- Department of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
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10
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Portelinha J, Duay SS, Yu SI, Heilemann K, Libardo MDJ, Juliano SA, Klassen JL, Angeles-Boza AM. Antimicrobial Peptides and Copper(II) Ions: Novel Therapeutic Opportunities. Chem Rev 2021; 121:2648-2712. [PMID: 33524257 DOI: 10.1021/acs.chemrev.0c00921] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The emergence of new pathogens and multidrug resistant bacteria is an important public health issue that requires the development of novel classes of antibiotics. Antimicrobial peptides (AMPs) are a promising platform with great potential for the identification of new lead compounds that can combat the aforementioned pathogens due to their broad-spectrum antimicrobial activity and relatively low rate of resistance emergence. AMPs of multicellular organisms made their debut four decades ago thanks to ingenious researchers who asked simple questions about the resistance to bacterial infections of insects. Questions such as "Do fruit flies ever get sick?", combined with pioneering studies, have led to an understanding of AMPs as universal weapons of the immune system. This review focuses on a subclass of AMPs that feature a metal binding motif known as the amino terminal copper and nickel (ATCUN) motif. One of the metal-based strategies of hosts facing a pathogen, it includes wielding the inherent toxicity of copper and deliberately trafficking this metal ion into sites of infection. The sudden increase in the concentration of copper ions in the presence of ATCUN-containing AMPs (ATCUN-AMPs) likely results in a synergistic interaction. Herein, we examine common structural features in ATCUN-AMPs that exist across species, and we highlight unique features that deserve additional attention. We also present the current state of knowledge about the molecular mechanisms behind their antimicrobial activity and the methods available to study this promising class of AMPs.
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Affiliation(s)
- Jasmin Portelinha
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Searle S Duay
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States.,Chemistry Department, Adamson University, 900 San Marcelino Street, Ermita, Manila 1000, Philippines
| | - Seung I Yu
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Kara Heilemann
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - M Daben J Libardo
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Samuel A Juliano
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Jonathan L Klassen
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, Connecticut 06269, United States
| | - Alfredo M Angeles-Boza
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States.,Institute of Material Science, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States
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11
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Sandhu G, Morrow MR, Booth V. Roles of histidine charge and cardiolipin in membrane disruption by antimicrobial peptides Gaduscidin-1 and Gaduscidin-2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183444. [PMID: 32822647 DOI: 10.1016/j.bbamem.2020.183444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/23/2020] [Accepted: 08/10/2020] [Indexed: 11/16/2022]
Abstract
Gad-1 and Gad-2 are helical, histidine-rich antimicrobial peptides (AMPs) from paralogous genes in cod. 15N and 2H solid state nuclear magnetic resonance (NMR) were used to characterize their lipid-bound structures and lipid interactions. Gad-1 was found to position in-plane in POPC: POPG bilayers. Gad-1 displayed greater effects than Gad-2 on lipid acyl chain order of POPE: POPG and POPE: POPG: CL bilayers, in keeping with its greater activity against E. coli. The effect of Gad-1 and Gad-2 on lipid bilayer order was only weakly affected by changes in pH, and hence changes in histidine charge. This was somewhat surprising for Gad-2 as this peptide's biological activity has been shown to be greater at low pH and thus the finding may point to the existence of functional interactions with non-lipid components of bacteria. The incorporation of cardiolipin into POPE: POPG bilayers in such a way as to preserve the overall charge of the bilayers did not alter Gad-1's effects on lipid acyl chain order parameters, which report on motions on the 10-5 s timescale. When cardiolipin and Gad-1 were both present, there were subtle changes on membrane dynamics at other timescales.
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Affiliation(s)
- Gagandeep Sandhu
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Michael R Morrow
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Valerie Booth
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, Canada; Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, Canada.
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12
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Paredes SD, Kim S, Rooney MT, Greenwood AI, Hristova K, Cotten ML. Enhancing the membrane activity of Piscidin 1 through peptide metallation and the presence of oxidized lipid species: Implications for the unification of host defense mechanisms at lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183236. [DOI: 10.1016/j.bbamem.2020.183236] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/14/2020] [Accepted: 02/25/2020] [Indexed: 12/12/2022]
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13
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Cetuk H, Maramba J, Britt M, Scott AJ, Ernst RK, Mihailescu M, Cotten ML, Sukharev S. Differential Interactions of Piscidins with Phospholipids and Lipopolysaccharides at Membrane Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5065-5077. [PMID: 32306736 DOI: 10.1021/acs.langmuir.0c00017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Piscidins 1 and 3 (P1 and P3) are potent antimicrobial peptides isolated from striped bass. Their mechanism of action involves formation of amphipathic α-helices on contact with phospholipids and destabilization of the microbial cytoplasmic membrane. The peptides are active against both Gram-positive and Gram-negative bacteria, suggesting easy passage across the outer membrane. Here, we performed a comparative study of these two piscidins at the air-water interface on lipopolysaccharide (LPS) monolayers modeling the outer bacterial surface of Gram-negative organisms and on phospholipid monolayers, which mimic the inner membrane. The results show that P1 and P3 are highly surface active (log KAW ∼ 6.8) and have similar affinities to phospholipid monolayers (log Klip ≈ 7.7). P1, which is more potent against Gram negatives, exhibits a much stronger partitioning into LPS monolayers (log KLPS = 8.3). Pressure-area isotherms indicate that under increasing lateral pressures, inserted P1 repartitions from phospholipid monolayers back to the subphase or to a more shallow position with in-plane areas of ∼170 Å2 per peptide, corresponding to fully folded amphipathic α-helices. In contrast, peptide expulsion from LPS occurs with areas of ∼35 Å2, suggesting that the peptides may not form the similarly oriented, rigid secondary structures when they avidly intercalate between LPS molecules. Patch-clamp experiments on Escherichia coli spheroplasts show that when P1 and P3 reach the outer surface of the bacterial cytoplasmic membrane, they produce fluctuating conductive structures at voltages above 80 mV. The data suggests that the strong activity of these piscidins against Gram-negative bacteria begins with the preferential accumulation of peptides in the outer LPS layer followed by penetration into the periplasm, where they form stable amphipathic α-helices upon contact with phospholipids and attack the energized inner membrane.
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Affiliation(s)
- Hannah Cetuk
- Biology Department, University of Maryland-College Park, 4094 Campus Drive, College Park, Maryland 20742, United States
| | - Joseph Maramba
- Biology Department, University of Maryland-College Park, 4094 Campus Drive, College Park, Maryland 20742, United States
| | - Madolyn Britt
- Biology Department, University of Maryland-College Park, 4094 Campus Drive, College Park, Maryland 20742, United States
| | - Alison J Scott
- Department of Microbial Pathogenesis, University of Maryland-Baltimore, Baltimore, Maryland 21201, United States
| | - Robert K Ernst
- Department of Microbial Pathogenesis, University of Maryland-Baltimore, Baltimore, Maryland 21201, United States
| | - Mihaela Mihailescu
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, United States
| | - Myriam L Cotten
- Department of Applied Science, College of William and Mary, Williamsburg, Virginia 23185, United States
| | - Sergei Sukharev
- Biology Department, University of Maryland-College Park, 4094 Campus Drive, College Park, Maryland 20742, United States
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14
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Oludiran A, Courson DS, Stuart MD, Radwan AR, Poutsma JC, Cotten ML, Purcell EB. How Oxygen Availability Affects the Antimicrobial Efficacy of Host Defense Peptides: Lessons Learned from Studying the Copper-Binding Peptides Piscidins 1 and 3. Int J Mol Sci 2019; 20:ijms20215289. [PMID: 31653020 PMCID: PMC6862162 DOI: 10.3390/ijms20215289] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 02/07/2023] Open
Abstract
The development of new therapeutic options against Clostridioides difficile (C. difficile) infection is a critical public health concern, as the causative bacterium is highly resistant to multiple classes of antibiotics. Antimicrobial host-defense peptides (HDPs) are highly effective at simultaneously modulating the immune system function and directly killing bacteria through membrane disruption and oxidative damage. The copper-binding HDPs piscidin 1 and piscidin 3 have previously shown potent antimicrobial activity against a number of Gram-negative and Gram-positive bacterial species but have never been investigated in an anaerobic environment. Synergy between piscidins and metal ions increases bacterial killing aerobically. Here, we performed growth inhibition and time-kill assays against C. difficile showing that both piscidins suppress proliferation of C. difficile by killing bacterial cells. Microscopy experiments show that the peptides accumulate at sites of membrane curvature. We find that both piscidins are effective against epidemic C. difficile strains that are highly resistant to other stresses. Notably, copper does not enhance piscidin activity against C. difficile. Thus, while antimicrobial activity of piscidin peptides is conserved in aerobic and anaerobic settings, the peptide-copper interaction depends on environmental oxygen to achieve its maximum potency. The development of pharmaceuticals from HDPs such as piscidin will necessitate consideration of oxygen levels in the targeted tissue.
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Affiliation(s)
- Adenrele Oludiran
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA.
| | - David S Courson
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA.
| | - Malia D Stuart
- Biology Department, Palomar College, San Marcos, CA 92069, USA.
| | - Anwar R Radwan
- Department of Chemistry, College of William and Mary, Williamsburg, VA 23185, USA.
| | - John C Poutsma
- Department of Chemistry, College of William and Mary, Williamsburg, VA 23185, USA.
| | - Myriam L Cotten
- Department of Applied Science, College of William and Mary, Williamsburg, VA 23185, USA.
| | - Erin B Purcell
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA.
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