1
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Melcrová A, Klein C, Roos WH. Membrane-Active Antibiotics Affect Domains in Bacterial Membranes as the First Step of Their Activity. NANO LETTERS 2024; 24:11800-11807. [PMID: 39145544 PMCID: PMC11440642 DOI: 10.1021/acs.nanolett.4c01873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 08/07/2024] [Accepted: 08/07/2024] [Indexed: 08/16/2024]
Abstract
The need to combat antimicrobial resistance is becoming more and more pressing. Here we investigate the working mechanism of a small cationic agent, N-alkylamide 3d, by conventional and high-speed atomic force microscopy. We show that N-alkylamide 3d interacts with the membrane of Staphylococcus aureus, where it changes the organization and dynamics of lipid domains. After this initial step, supramolecular structures of the antimicrobial agent attach on top of the affected membrane gradually, covering it entirely. These results demonstrate that lateral domains in the bacterial membranes might be affected by small antimicrobial agents more often than anticipated. At the same time, we show a new dual-step activity of N-alkylamide 3d that not only destroys the lateral membrane organization but also effectively covers the whole membrane with aggregates. This final step could render the membrane inaccessible from the outside and possibly prevent signaling and waste disposal of living bacteria.
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Affiliation(s)
- Adéla Melcrová
- Molecular
Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, 9712 AG Groningen, The Netherlands
| | - Christiaan Klein
- Molecular
Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, 9712 AG Groningen, The Netherlands
| | - Wouter H. Roos
- Molecular
Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, 9712 AG Groningen, The Netherlands
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2
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Melcrová A, Maity S, Melcr J, de Kok NAW, Gabler M, van der Eyden J, Stensen W, Svendsen JSM, Driessen AJM, Marrink SJ, Roos WH. Lateral membrane organization as target of an antimicrobial peptidomimetic compound. Nat Commun 2023; 14:4038. [PMID: 37419980 PMCID: PMC10328936 DOI: 10.1038/s41467-023-39726-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 06/20/2023] [Indexed: 07/09/2023] Open
Abstract
Antimicrobial resistance is one of the leading concerns in medical care. Here we study the mechanism of action of an antimicrobial cationic tripeptide, AMC-109, by combining high speed-atomic force microscopy, molecular dynamics, fluorescence assays, and lipidomic analysis. We show that AMC-109 activity on negatively charged membranes derived from Staphylococcus aureus consists of two crucial steps. First, AMC-109 self-assembles into stable aggregates consisting of a hydrophobic core and a cationic surface, with specificity for negatively charged membranes. Second, upon incorporation into the membrane, individual peptides insert into the outer monolayer, affecting lateral membrane organization and dissolving membrane nanodomains, without forming pores. We propose that membrane domain dissolution triggered by AMC-109 may affect crucial functions such as protein sorting and cell wall synthesis. Our results indicate that the AMC-109 mode of action resembles that of the disinfectant benzalkonium chloride (BAK), but with enhanced selectivity for bacterial membranes.
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Affiliation(s)
- Adéla Melcrová
- Molecular Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Groningen, the Netherlands
| | - Sourav Maity
- Molecular Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Groningen, the Netherlands
| | - Josef Melcr
- Molecular Dynamics, Groningen Biomolecular Sciences & Biotechnology Institute, Rijksuniversiteit Groningen, Groningen, the Netherlands
| | - Niels A W de Kok
- Molecular Microbiology, Groningen Biomolecular Sciences & Biotechnology Institute, Rijksuniversiteit Groningen, Groningen, the Netherlands
| | - Mariella Gabler
- Molecular Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Groningen, the Netherlands
| | - Jonne van der Eyden
- Molecular Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Groningen, the Netherlands
| | - Wenche Stensen
- Department of Chemistry, UiT Arctic University of Norway, Tromsø, Norway
| | - John S M Svendsen
- Department of Chemistry, UiT Arctic University of Norway, Tromsø, Norway
| | - Arnold J M Driessen
- Molecular Microbiology, Groningen Biomolecular Sciences & Biotechnology Institute, Rijksuniversiteit Groningen, Groningen, the Netherlands
| | - Siewert J Marrink
- Molecular Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Groningen, the Netherlands
- Molecular Dynamics, Groningen Biomolecular Sciences & Biotechnology Institute, Rijksuniversiteit Groningen, Groningen, the Netherlands
| | - Wouter H Roos
- Molecular Biophysics, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Groningen, the Netherlands.
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3
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He Y, Lei JN, Zhu S, Liu YF, Xu YJ. Monomethyl branched-chain fatty acids-a pearl dropped in the ocean. Crit Rev Food Sci Nutr 2023; 64:9045-9057. [PMID: 37140184 DOI: 10.1080/10408398.2023.2207655] [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] [Indexed: 05/05/2023]
Abstract
As an emerging group of bioactive fatty acids, monomethyl branched-chain fatty acids (mmBCFAs) have sparked the interest of many researchers both domestically and internationally. In addition to documenting the importance of mmBCFAs for growth and development, there is increasing evidence that mmBCFAs are highly correlated with obesity and insulin resistance. According to previous pharmacological investigations, mmBCFAs also exhibit anti-inflammatory effects and anticancer properties. This review summarized the distribution of mmBCFAs, which are widely found in dairy products, ruminants, fish, and fermented foods. Besides, we discuss the biosynthesis pathway in different species and detection methods of mmBCFAs. With the hope to unveil their mechanisms of action, we recapitulated detailed the nutrition and health benefits of mmBCFAs. Furthermore, this study provides a thorough, critical overview of the current state of the art, upcoming difficulties, and trends in mmBCFAs.
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Affiliation(s)
- Yuan He
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, National Engineering Reacher Center for Functional Food, National Engineering Laboratory for Cereal Fermentation Technology, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Jing-Nan Lei
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, National Engineering Reacher Center for Functional Food, National Engineering Laboratory for Cereal Fermentation Technology, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Shuang Zhu
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, National Engineering Reacher Center for Functional Food, National Engineering Laboratory for Cereal Fermentation Technology, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Yuan-Fa Liu
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, National Engineering Reacher Center for Functional Food, National Engineering Laboratory for Cereal Fermentation Technology, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Yong-Jiang Xu
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, National Engineering Reacher Center for Functional Food, National Engineering Laboratory for Cereal Fermentation Technology, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
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4
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Lillja J, Lanekoff I. Quantitative determination of sn-positional phospholipid isomers in MS n using silver cationization. Anal Bioanal Chem 2022; 414:7473-7482. [PMID: 35731255 PMCID: PMC9482905 DOI: 10.1007/s00216-022-04173-6] [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: 04/05/2022] [Revised: 05/13/2022] [Accepted: 06/09/2022] [Indexed: 11/18/2022]
Abstract
Glycerophospholipids are one of the fundamental building blocks for life. The acyl chain connectivity to the glycerol backbone constitutes different sn-positional isomers, which have great diversity and importance for biological function. However, to fully realize their impact on function, analytical techniques that can identify and quantify sn-positional isomers in chemically complex biological samples are needed. Here, we utilize silver ion cationization in combination with tandem mass spectrometry (MSn) to identify sn-positional isomers of phosphatidylcholine (PC) species. In particular, a labile carbocation is generated through a neutral loss (NL) of AgH, the dissociation of which provides diagnostic product ions that correspond to acyl chains at the sn-1 or sn-2 position. The method is comparable to currently available methods, has a sensitivity in the nM-µM range, and is compatible with quantitative imaging using mass spectrometry in MS4. The results reveal a large difference in isomer concentrations and the ion images show that the sn-positional isomers PC 18:1_18:0 are homogeneously distributed, whereas PC 18:1_16:0 and PC 20:1_16:0 show distinct localizations to sub-hippocampal structures.
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Affiliation(s)
- Johan Lillja
- Department of Chemistry - BMC (576), Uppsala University, 751 23, Uppsala, Sweden
| | - Ingela Lanekoff
- Department of Chemistry - BMC (576), Uppsala University, 751 23, Uppsala, Sweden.
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5
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Carey AB, Ashenden A, Köper I. Model architectures for bacterial membranes. Biophys Rev 2022; 14:111-143. [PMID: 35340604 PMCID: PMC8921416 DOI: 10.1007/s12551-021-00913-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/14/2021] [Indexed: 02/06/2023] Open
Abstract
The complex composition of bacterial membranes has a significant impact on the understanding of pathogen function and their development towards antibiotic resistance. In addition to the inherent complexity and biosafety risks of studying biological pathogen membranes, the continual rise of antibiotic resistance and its significant economical and clinical consequences has motivated the development of numerous in vitro model membrane systems with tuneable compositions, geometries, and sizes. Approaches discussed in this review include liposomes, solid-supported bilayers, and computational simulations which have been used to explore various processes including drug-membrane interactions, lipid-protein interactions, host-pathogen interactions, and structure-induced bacterial pathogenesis. The advantages, limitations, and applicable analytical tools of all architectures are summarised with a perspective for future research efforts in architectural improvement and elucidation of resistance development strategies and membrane-targeting antibiotic mechanisms. Supplementary Information The online version contains supplementary material available at 10.1007/s12551-021-00913-7.
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Affiliation(s)
- Ashley B. Carey
- Institute for Nanoscale Science and Technology, College for Science and Engineering, Flinders University, Adelaide, SA 5042 Australia
| | - Alex Ashenden
- Institute for Nanoscale Science and Technology, College for Science and Engineering, Flinders University, Adelaide, SA 5042 Australia
| | - Ingo Köper
- Institute for Nanoscale Science and Technology, College for Science and Engineering, Flinders University, Adelaide, SA 5042 Australia
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6
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Miller LN, Blake MJ, Page EF, Castillo HB, Calhoun TR. Phosphate Ions Alter the Binding of Daptomycin to Living Bacterial Cell Surfaces. ACS Infect Dis 2021; 7:3088-3095. [PMID: 34605244 DOI: 10.1021/acsinfecdis.1c00397] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Advancements in antibiotic drug design are often hindered by missing information on how these small molecules interact with living cells. The antibiotic, daptomycin, has found clinical success and an emerging resistance, but a comprehensive picture of its mechanism of action has remained elusive. Using a surface-specific spectroscopy technique, second harmonic generation, we are able to quantitatively assess the binding of daptomycin to living cell membranes without the addition of exogenous labels. Our results reveal similar binding affinities for both Gram-positive and Gram-negative bacteria studied, including Escherichia coli. More importantly, we show that the presence of phosphate ions influences the binding of daptomycin to the Gram-positive bacterium Enterococcus faecalis. The role of environmental phosphate has not previously been considered in any proposed mechanism, and its implications are expected to be important in vivo.
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Affiliation(s)
- Lindsey N. Miller
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Marea J. Blake
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Eleanor F. Page
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Hannah B. Castillo
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Tessa R. Calhoun
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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7
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Abstract
Spherical ordering from small molecules is a subject of intense interest to chemists. The inherent capability of amphiphiles to assemble spontaneously is the unique feature of the evolutionary process of life. Self-assembly is prevalent in biology and has attracted the interest of scientists across several disciplines. This is because scientists have realized that nature has extensively used this inherent organizational power contained in the molecules. Judicious use of the self-assembly principle is the cornerstone of nature's exotic assemblies. These exotic assemblies lead to unimaginable functions in biology that might not have been predicted from the monomer building blocks alone. Recently, a number of chemical systems that self-assemble in aqueous or organic solvents to form vesicles were reported. This account provides advances made from our laboratory toward designing and understanding the mechanism of formation of spherical vesicular assembly. A bottom-up approach for the de novo design of vesicles using nonlipidated molecular architecture will be a paradigm shift in vesicular research. Vesicles act as a protocell model for studying the origin and evolution of cellular life. They could also act as excellent model systems for studying the fusion of cells and membrane transport. Self-assembled vesicles have enormous potential for several applications such as drug and biomolecule delivery to cells and in materials science. These aspects along with the dynamic nature of vesicular assembly have attracted researchers to the study of spherical assemblies. The common belief was that the molecules that form vesicles must have one polar head and two hydrophobic tails. All attempts to synthesize vesicles are by mimicking nature's strategy, which mainly involves the self-assembly of lipid amphiphiles through a bilayer-like arrangement. Pseudopeptide-based molecules with the ability to form vesicles have changed this long-standing notion. In addition to chemical and medical applications, these peptide vesicles could act as models for protocells, membrane fusion, and the study of the vesiculation mechanism. This Account highlights the progress made toward a heuristic approach to the de novo design of vesicles using pseudopeptides as building blocks.A large number of diverse classes of pseudopeptides showed vesicular assembly. Various acyclic and cyclic molecules were designed and synthesized that showed spherical vesicular assembly. Cystine-based macrocyclic peptides showed drug encapsulation and release. Polymersomes with unusual topology, self-assembling tripodal ligands, and molecules containing amino acids such as lysine, leucine, cystine, and serine were synthesized. The incorporation of a wide variety of amino acids in the vesicle-forming peptides could enhance their scope and applications. The mechanism of vesiculation was also investigated using these designer molecules.
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Affiliation(s)
- V. Haridas
- Department of Chemistry, Indian Institute of Technology Delhi (IITD), New Delhi 110016, India
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8
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Trautmann A, Schleicher L, Deusch S, Gätgens J, Steuber J, Seifert J. Short-Chain Fatty Acids Modulate Metabolic Pathways and Membrane Lipids in Prevotella bryantii B 14. Proteomes 2020; 8:28. [PMID: 33081314 PMCID: PMC7709123 DOI: 10.3390/proteomes8040028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/26/2022] Open
Abstract
Short-chain fatty acids (SCFAs) are bacterial products that are known to be used as energy sources in eukaryotic hosts, whereas their role in the metabolism of intestinal microbes is rarely explored. In the present study, acetic, propionic, butyric, isobutyric, valeric, and isovaleric acid, respectively, were added to a newly defined medium containing Prevotella bryantii B14 cells. After 8 h and 24 h, optical density, pH and SCFA concentrations were measured. Long-chain fatty acid (LCFA) profiles of the bacterial cells were analyzed via gas chromatography-time of flight-mass spectrometry (GC-ToF MS) and proteins were quantified using a mass spectrometry-based, label-free approach. Cultures supplemented with single SCFAs revealed different growth behavior. Structural features of the respective SCFAs were identified in the LCFA profiles, which suggests incorporation into the bacterial membranes. The proteomes of cultures supplemented with acetic and valeric acid differed by an increased abundance of outer membrane proteins. The proteome of the isovaleric acid supplementation showed an increase of proteins in the amino acid metabolism. Our findings indicate a possible interaction between SCFAs, the lipid membrane composition, the abundance of outer membrane proteins, and a modulation of branched chain amino acid biosynthesis by isovaleric acid.
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Affiliation(s)
- Andrej Trautmann
- Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany; (A.T.); (S.D.)
| | - Lena Schleicher
- Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany; (L.S.); (J.S.)
| | - Simon Deusch
- Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany; (A.T.); (S.D.)
| | - Jochem Gätgens
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Julia Steuber
- Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany; (L.S.); (J.S.)
| | - Jana Seifert
- Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany; (A.T.); (S.D.)
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9
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Mescola A, Ragazzini G, Alessandrini A. Daptomycin Strongly Affects the Phase Behavior of Model Lipid Bilayers. J Phys Chem B 2020; 124:8562-8571. [PMID: 32886515 DOI: 10.1021/acs.jpcb.0c06640] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Daptomycin (DAP) is a calcium-dependent cyclic lipopeptide with great affinity for negatively charged phospholipids bearing the phosphatidylglycerol (PG) headgroup and has been used since 2003 as a last resort antibiotic in the treatment of severe infections caused by Gram-positive bacteria. The first step of its mechanism of action involves the interaction with the bacterial membrane, which not only represents a physical barrier but also accommodates transmembrane proteins, such as receptors, transporters, and enzymes, whose activity is crucial for the survival of bacteria. This results in a less efficient development of resistance strategies by pathogens compared to common antibiotics that activate or inhibit biochemical pathways connected to specific target proteins. Although already on the market, the molecular mechanism of action of DAP is still a controversial subject of investigation and it is most likely the result of a combination of distinct effects. Understanding how DAP targets the membrane of pathogens could be of great help in finding its analogues that could better avoid the development of resistance. Here, exploiting fluorescence microscopy and atomic force microscopy (AFM), we demonstrated that DAP affects the thermodynamic behavior of lipid mixtures containing PG moieties. Regardless of whether the PG lipids are in the liquid or solid phase, DAP preferably interacts with this headgroup and is able to penetrate more deeply into the lipid bilayer in the regions where this headgroup is present. In particular, considering the results of an AFM/spectroscopy investigation, DAP appears to produce a stiffening effect of the domains where PG lipids are mainly in the fluid phase, whereas it causes fluidification of the domains where PG lipids are in the solid phase.
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Affiliation(s)
- Andrea Mescola
- CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy
| | - Gregorio Ragazzini
- CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy.,Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy
| | - Andrea Alessandrini
- CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy.,Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy
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10
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Camilo CJJ, Leite DOD, Silva ARA, Menezes IRA, Coutinho HDM, Costa JGM. Lipid vesicles: applications, principal components and methods used in their formulations: A review. ACTA BIOLÓGICA COLOMBIANA 2020. [DOI: 10.15446/abc.v25n2.74830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Liposomes and niosomes are currently the most studied lipid vesicles in the nanomedicine field. The system formed by a phospholipid bilayer in aqueous medium allows these vesicles to carry both hydrophilic and lipophilic compounds, providing an increase in solubility of drugs lready used in conventional therapy. The focus on the development of these vesicles should be directed to determining the ideal composition, with low toxicity, biocompatibility and which remains stable for long periods. These characteristics are related to the components used for formulation and the substances that will be encapsulated. Another important point relates to the methods used during formulation, which are important in determining the type of vesicle formed, whether these be large or small, unilamellar or multilamellar. Because of the deliberate actions applied in the development of these vesicles, this review sought to gather updated information regarding the different methods used, including their main components while considering the behavior of each of them when used in different formulations. Also, data showing the importance of formulations in the medical field evidencing studies performed with liposome and niosome vesicles as promising in this area, and others, were included. The approach allows a better understanding of the participation of components in formulations such as cholesterol and non-ionic surfactants, as well as the basis for choosing the ideal components and methods for future research in the development of these vesicles.
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11
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Visvabharathy L, Genardi S, Cao L, He Y, Alonzo F, Berdyshev E, Wang CR. Group 1 CD1-restricted T cells contribute to control of systemic Staphylococcus aureus infection. PLoS Pathog 2020; 16:e1008443. [PMID: 32343740 PMCID: PMC7188215 DOI: 10.1371/journal.ppat.1008443] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/28/2020] [Indexed: 11/19/2022] Open
Abstract
Staphylococcus aureus (SA) is the causative agent of both skin/soft tissue infections as well as invasive bloodstream infections. Though vaccines have been developed to target both humoral and T cell-mediated immune responses against SA, they have largely failed due to lack of protective efficacy. Group 1 CD1-restricted T cells recognize lipid rather than peptide antigens. Previously found to recognize lipids derived from cell wall of Mycobacterium tuberculosis (Mtb), these cells were associated with protection against Mtb infection in humans. Using a transgenic mouse model expressing human group 1 CD1 molecules (hCD1Tg), we demonstrate that group 1 CD1-restricted T cells can recognize SA-derived lipids in both immunization and infection settings. Systemic infection of hCD1Tg mice showed that SA-specific group 1 CD1-restricted T cell response peaked at 10 days post-infection, and hCD1Tg mice displayed significantly decreased kidney pathology at this time point compared with WT control mice. Immunodominant SA lipid antigens recognized by group 1 CD1-restricted T cells were comprised mainly of cardiolipin and phosphatidyl glycerol, with little contribution from lysyl-phosphatidyl glycerol which is a unique bacterial lipid not present in mammals. Group 1 CD1-restricted T cell lines specific for SA lipids also conferred protection against SA infection in the kidney after adoptive transfer. They were further able to effectively control SA replication in vitro through direct antigen presentation by group 1 CD1-expressing BMDCs. Together, our data demonstrate a previously unknown role for group 1 CD1-restricted SA lipid-specific T cells in the control of systemic MRSA infection.
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Affiliation(s)
- Lavanya Visvabharathy
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, United States of America
| | - Samantha Genardi
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, United States of America
| | - Liang Cao
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, United States of America
| | - Ying He
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, United States of America
| | - Francis Alonzo
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University, Maywood, United States of America
| | - Evgeny Berdyshev
- Department of Medicine, National Jewish Health, Denver, United States of America
| | - Chyung-Ru Wang
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, United States of America
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12
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Malanovic N, Marx L, Blondelle SE, Pabst G, Semeraro EF. Experimental concepts for linking the biological activities of antimicrobial peptides to their molecular modes of action. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183275. [PMID: 32173291 DOI: 10.1016/j.bbamem.2020.183275] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023]
Abstract
The search for novel compounds to combat multi-resistant bacterial infections includes exploring the potency of antimicrobial peptides and derivatives thereof. Complementary to high-throughput screening techniques, biophysical and biochemical studies of the biological activity of these compounds enable deep insight, which can be exploited in designing antimicrobial peptides with improved efficacy. This approach requires the combination of several techniques to study the effect of such peptides on both bacterial cells and simple mimics of their cell envelope, such as lipid-only vesicles. These efforts carry the challenge of bridging results across techniques and sample systems, including the proper choice of membrane mimics. This review describes some important concepts toward the development of potent antimicrobial peptides and how they translate to frequently applied experimental techniques, along with an outline of the biophysics pertaining to the killing mechanism of antimicrobial peptides.
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Affiliation(s)
- Nermina Malanovic
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria.
| | - Lisa Marx
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria
| | | | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria
| | - Enrico F Semeraro
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria
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13
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Miller LN, Brewer WT, Williams JD, Fozo EM, Calhoun TR. Second Harmonic Generation Spectroscopy of Membrane Probe Dynamics in Gram-Positive Bacteria. Biophys J 2019; 117:1419-1428. [PMID: 31586521 DOI: 10.1016/j.bpj.2019.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/11/2019] [Accepted: 09/13/2019] [Indexed: 11/17/2022] Open
Abstract
Bacterial membranes are complex mixtures with dispersity that is dynamic over scales of both space and time. To capture adsorption onto and transport within these mixtures, we conduct simultaneous second harmonic generation (SHG) and two-photon fluorescence measurements on two different gram-positive bacterial species as the cells uptake membrane-specific probe molecules. Our results show that SHG not only can monitor the movement of small molecules across membrane leaflets but also is sensitive to higher-level ordering of the molecules within the membrane. Further, we show that the membranes of Staphylococcus aureus remain more dynamic after longer times at room temperature in comparison to Enterococcus faecalis. Our findings provide insight into the variability of activities seen between structurally similar molecules in gram-positive bacteria while also demonstrating the power of SHG to examine these dynamics.
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Affiliation(s)
- Lindsey N Miller
- Department of Chemistry, University of Tennesseee, Knoxville, Tennessee
| | - William T Brewer
- Department of Microbiology, University of Tennesseee, Knoxville, Tennessee
| | - Julia D Williams
- Department of Microbiology, University of Tennesseee, Knoxville, Tennessee
| | - Elizabeth M Fozo
- Department of Microbiology, University of Tennesseee, Knoxville, Tennessee
| | - Tessa R Calhoun
- Department of Chemistry, University of Tennesseee, Knoxville, Tennessee.
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14
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Abstract
Triclosan and chloroxylenol are broad-spectrum biocides used extensively in healthcare and consumer products. They have been suggested to perturb the structure of bacterial membranes, but studies so far have not considered that most bacterial membranes contain large amounts of branched-chain lipids. Here, molecular dynamics simulation is used to examine the effect of the two biocides on membranes consisting of lipids with methyl-branched chains, cyclopropanated chains, and nonbranched chains. It is shown that triclosan and chloroxylenol induced a phase transition in membranes from a liquid-crystalline to a liquid-ordered phase irrespective of the presence and nature of branching groups. At high concentration, chloroxylenol promoted chain interdigitation. Our results suggest that triclosan and chloroxylenol decrease the degree of fluidity of membranes and that this effect is more pronounced in bacterial membranes. As a result, their biocidal activity could be associated with a change in the function of membrane proteins.
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Affiliation(s)
- David Poger
- School of Chemistry & Molecular Biosciences , The University of Queensland , Brisbane QLD 4072 , Australia
| | - Alan E Mark
- School of Chemistry & Molecular Biosciences , The University of Queensland , Brisbane QLD 4072 , Australia
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15
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Abstract
The rise of antibiotic resistant bacteria requires unconventional strategies toward efficient chemotherapeutic agents, preferably with alternative mechanisms of action. The bacterial cell membrane has become an appealing target since its essential and highly conservative structure are key challenges to resistance mechanisms. Inspired by natural antimicrobial peptides, research on membrane-targeting antimicrobials has been growing out of the peptide space. The pursuit of more druggable molecules led to the discovery that the pharmacophore of antimicrobial peptides is smaller than anticipated. Several promising classes of membrane-targeting antimicrobials have been discovered, such as ceragenins, reutericyclines, carbohydrate amphiphiles - among others. This review will discuss the most recent findings on membrane-targeting antibiotics, focusing on small molecules outside the antimicrobial peptide molecular space.
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16
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Perez-Lopez MI, Mendez-Reina R, Trier S, Herrfurth C, Feussner I, Bernal A, Forero-Shelton M, Leidy C. Variations in carotenoid content and acyl chain composition in exponential, stationary and biofilm states of Staphylococcus aureus, and their influence on membrane biophysical properties. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:978-987. [PMID: 30771288 DOI: 10.1016/j.bbamem.2019.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/01/2019] [Accepted: 02/04/2019] [Indexed: 01/01/2023]
Abstract
Bacteria are often found in close association with surfaces, resulting in the formation of biofilms. In Staphylococcus aureus (S. aureus), biofilms are implicated in the resilience of chronic infections, presenting a serious clinical problem world-wide. Here, S. aureus biofilms are grown under flow within clinical catheters at 37 °C. The lipid composition and biophysical properties of lipid extracts from these biofilms are compared with those from exponential growth and stationary phase cells. Biofilms show a reduction in iso and anteiso branching compensated by an increase in saturated fatty acids compared to stationary phase. A drastic reduction in carotenoid levels is also observed during biofilm formation. Thermotropic measurements of Laurdan GP and DPH polarization, show a reduction of lipid packing at 37 °C for biofilms compared to stationary phase. We studied the effects of carotenoid content on DMPG and DPPG model membranes showing trends in thermotropic behavior consistent with those observed in bacterial isolates, indicating that carotenoids participate in modulating lipid packing. Additionally, bending elastic constant (kc) measurements using vesicle fluctuation analysis (VFA) show that the presence of carotenoids can increase membrane bending rigidity. The antimicrobial peptide Magainin H2 was less activity on liposomes composed of stationary phase compared to biofilms or exponential growth isolates. This study contributes to an understanding of how Staphylococcus aureus modulates the composition of its membrane lipids, and how those changes affect the biophysical properties of membranes, which in turn may play a role in its virulence and its resistance to different membrane-active antimicrobial agents.
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Affiliation(s)
- Maria Isabel Perez-Lopez
- Department of Physics, Universidad de los Andes, Bogotá, Colombia; Biological Sciences Department, Universidad de los Andes, Bogotá, Colombia
| | | | - Steve Trier
- Department of Physics, Universidad de los Andes, Bogotá, Colombia
| | - Cornelia Herrfurth
- Department of Plant Biochemistry, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Goettingen, Germany; Department of Plant Biochemistry, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Adriana Bernal
- Biological Sciences Department, Universidad de los Andes, Bogotá, Colombia
| | | | - Chad Leidy
- Department of Physics, Universidad de los Andes, Bogotá, Colombia.
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17
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Abstract
Many molecular features contribute to the antimicrobial activity of peptides. One aspect that contributes to the antimicrobial activity of a peptide, in many cases, results from the fact that many antimicrobial peptides are polycationic and the lipids on the surface of bacteria are often anionic. In certain cases this can result in the clustering of anionic lipids as a result of the binding of the cationic peptide to the surface of the bacterial membrane. This lipid clustering can be detrimental to the viability of the bacteria to which the peptide binds. Several factors, including the charge, size, and conformational flexibility of the peptide, will determine the efficiency of lipid clustering. In addition, the lipid composition of the bacterial membrane is very variable, and it plays a critical role in this mechanism. As a result, one can test the importance of this factor by determining the species specificity of the antimicrobial activity of the peptide. The molecular mechanism by which lipid clustering affects bacterial viability is uncertain in many cases. This phenomenon can be used to increase the antimicrobial potency of peptides in some case and can also predict the bacterial species specificity of some agents.
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Affiliation(s)
- Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.
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18
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Omardien S, Drijfhout JW, Zaat SA, Brul S. Cationic Amphipathic Antimicrobial Peptides Perturb the Inner Membrane of Germinated Spores Thus Inhibiting Their Outgrowth. Front Microbiol 2018; 9:2277. [PMID: 30319583 PMCID: PMC6168669 DOI: 10.3389/fmicb.2018.02277] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/06/2018] [Indexed: 11/13/2022] Open
Abstract
The mode of action of four cationic amphipathic antimicrobial peptides (AMPs) was evaluated against the non-pathogenic, Gram-positive, spore-forming bacterium, Bacillus subtilis. The AMPs were TC19, TC84, BP2, and the lantibiotic Nisin A. TC19 and TC84 were derived from the human thrombocidin-1. Bactericidal peptide 2 (BP2) was derived from the human bactericidal permeability increasing protein (BPI). We employed structured illumination microscopy (SIM), fluorescence microscopy, Alexa 488-labeled TC84, B. subtilis mutants producing proteins fused to the green fluorescent protein (GFP) and single-cell live imaging to determine the effects of the peptides against spores. TC19, TC84, BP2, and Nisin A showed to be bactericidal against germinated spores by perturbing the inner membrane, thus preventing outgrowth to vegetative cells. Single cell live imaging showed that the AMPs do not affect the germination process, but the burst time and subsequent generation time of vegetative cells. Alexa 488-labeled TC84 suggested that the TC84 might be binding to the dormant spore-coat. Therefore, dormant spores were also pre-coated with the AMPs and cultured on AMP-free culture medium during single-cell live imaging. Pre-coating of the spores with TC19, TC84, and BP2 had no effect on the germination process, and variably affected the burst time and generation time. However, the percentage of spores that burst and grew out into vegetative cells was drastically lower when pre-coated with Nisin A, suggesting a novel application potential of this lantibiotic peptide against spores. Our findings contribute to the understanding of AMPs and show the potential of AMPs as eventual therapeutic agents against spore-forming bacteria.
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Affiliation(s)
- Soraya Omardien
- Swammerdam Institute for Life Sciences, Department of Molecular Biology and Microbial Food Safety, University of Amsterdam, Amsterdam, Netherlands
| | | | - Sebastian A Zaat
- Department of Medical Microbiology, Centre for Infection and Immunity Amsterdam (CINIMA), Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Stanley Brul
- Swammerdam Institute for Life Sciences, Department of Molecular Biology and Microbial Food Safety, University of Amsterdam, Amsterdam, Netherlands
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19
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Sen S, Sirobhushanam S, Johnson SR, Song Y, Tefft R, Gatto C, Wilkinson BJ. Growth-Environment Dependent Modulation of Staphylococcus aureus Branched-Chain to Straight-Chain Fatty Acid Ratio and Incorporation of Unsaturated Fatty Acids. PLoS One 2016; 11:e0165300. [PMID: 27788193 PMCID: PMC5082858 DOI: 10.1371/journal.pone.0165300] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 10/07/2016] [Indexed: 12/14/2022] Open
Abstract
The fatty acid composition of membrane glycerolipids is a major determinant of Staphylococcus aureus membrane biophysical properties that impacts key factors in cell physiology including susceptibility to membrane active antimicrobials, pathogenesis, and response to environmental stress. The fatty acids of S. aureus are considered to be a mixture of branched-chain fatty acids (BCFAs), which increase membrane fluidity, and straight-chain fatty acids (SCFAs) that decrease it. The balance of BCFAs and SCFAs in USA300 strain JE2 and strain SH1000 was affected considerably by differences in the conventional laboratory medium in which the strains were grown with media such as Mueller-Hinton broth and Luria broth resulting in high BCFAs and low SCFAs, whereas growth in Tryptic Soy Broth and Brain-Heart Infusion broth led to reduction in BCFAs and an increase in SCFAs. Straight-chain unsaturated fatty acids (SCUFAs) were not detected. However, when S. aureus was grown ex vivo in serum, the fatty acid composition was radically different with SCUFAs, which increase membrane fluidity, making up a substantial proportion of the total (<25%) with SCFAs (>37%) and BCFAs (>36%) making up the rest. Staphyloxanthin, an additional major membrane lipid component unique to S. aureus, tended to be greater in content in cells with high BCFAs or SCUFAs. Cells with high staphyloxanthin content had a lower membrane fluidity that was attributed to increased production of staphyloxanthin. S. aureus saves energy and carbon by utilizing host fatty acids for part of its total fatty acids when growing in serum, which may impact biophysical properties and pathogenesis given the role of SCUFAs in virulence. The nutritional environment in which S. aureus is grown in vitro or in vivo in an infection is likely to be a major determinant of membrane fatty acid composition.
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Affiliation(s)
- Suranjana Sen
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Sirisha Sirobhushanam
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Seth R. Johnson
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Yang Song
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Ryan Tefft
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Brian J. Wilkinson
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
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20
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Malanovic N, Lohner K. Antimicrobial Peptides Targeting Gram-Positive Bacteria. Pharmaceuticals (Basel) 2016; 9:E59. [PMID: 27657092 PMCID: PMC5039512 DOI: 10.3390/ph9030059] [Citation(s) in RCA: 230] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/07/2016] [Accepted: 09/13/2016] [Indexed: 01/01/2023] Open
Abstract
Antimicrobial peptides (AMPs) have remarkably different structures as well as biological activity profiles, whereupon most of these peptides are supposed to kill bacteria via membrane damage. In order to understand their molecular mechanism and target cell specificity for Gram-positive bacteria, it is essential to consider the architecture of their cell envelopes. Before AMPs can interact with the cytoplasmic membrane of Gram-positive bacteria, they have to traverse the cell wall composed of wall- and lipoteichoic acids and peptidoglycan. While interaction of AMPs with peptidoglycan might rather facilitate penetration, interaction with anionic teichoic acids may act as either a trap for AMPs or a ladder for a route to the cytoplasmic membrane. Interaction with the cytoplasmic membrane frequently leads to lipid segregation affecting membrane domain organization, which affects membrane permeability, inhibits cell division processes or leads to delocalization of essential peripheral membrane proteins. Further, precursors of cell wall components, especially the highly conserved lipid II, are directly targeted by AMPs. Thereby, the peptides do not inhibit peptidoglycan synthesis via binding to proteins like common antibiotics, but form a complex with the precursor molecule, which in addition can promote pore formation and membrane disruption. Thus, the multifaceted mode of actions will make AMPs superior to antibiotics that act only on one specific target.
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Affiliation(s)
- Nermina Malanovic
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Austria.
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Austria.
- BioTechMed Graz, Humboldtstrasse 50/III, 8010 Graz, Austria.
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21
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The importance of cyclic structure for Labaditin on its antimicrobial activity against Staphylococcus aureus. Colloids Surf B Biointerfaces 2016; 148:453-459. [PMID: 27665378 DOI: 10.1016/j.colsurfb.2016.09.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/04/2016] [Accepted: 09/11/2016] [Indexed: 01/24/2023]
Abstract
Antimicrobial resistance has reached alarming levels in many countries, thus leading to a search for new classes of antibiotics, such as antimicrobial peptides whose activity is exerted by interacting specifically with the microorganism membrane. In this study, we investigate the molecular-level mechanism of action for Labaditin (Lo), a 10-amino acid residue cyclic peptide from Jatropha multifida with known bactericidal activity against Streptococcus mutans. We show that Lo is also effective against Staphylococcus aureus (S. aureus) but this does not apply to its linear analogue (L1). Using polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), we observed with that the secondary structure of Lo was preserved upon interacting with Langmuir monolayers from a phospholipid mixture mimicking S. aureus membrane, in contrast to L1. This structure preservation for the rigid, cyclic Lo is key for the self-assembly of peptide nanotubes that induce pore formation in large unilamellar vesicles (LUVs), according to permeability assays and dynamic light scattering measurements. In summary, the comparison between Labaditin (Lo) and its linear analogue L1 allowed us to infer that the bactericidal activity of Lo is more related to its interaction with the membrane. It does not require specific metabolic targets, which makes cyclic peptides promising for antibiotics without bacteria resistance.
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