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Wibel R, van Hoogevest P, Drescher S. The role of phospholipids in drug delivery formulations - Recent advances presented at the Researcher's Day 2023 Conference of the Phospholipid Research Center Heidelberg. Eur J Pharm Biopharm 2024; 197:114215. [PMID: 38350530 DOI: 10.1016/j.ejpb.2024.114215] [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: 01/02/2024] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/15/2024]
Abstract
This Focus on Meetings contribution summarizes recent advances in the research on phospholipids and their applications for drug delivery and analytical purposes that have been presented at the hybrid Researcher's Day 2023 Conference of the Phospholipid Research Center (PRC), held on July 3-5, 2023, in Bad Dürkheim, Germany. The PRC is a non-profit organization focused on expanding and sharing scientific and technological knowledge of phospholipids in pharmaceutical and other applications. This is accomplished by, e.g., funding doctoral and postdoctoral research projects. The progress made with these projects is presented at the Researcher's Day Conference every two years. Four main topics were presented and discussed in various lectures: (1) formulation of phospholipid-based nanocarriers, (2) therapeutic applications of phospholipids and phospholipid-based nanocarriers, (3) phospholipids as excipients in oral, dermal, and parenteral dosage forms, and (4) interactions of phospholipids and phospholipid-based vesicles in biological environment and their use as analytical platforms.
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Affiliation(s)
- Richard Wibel
- Phospholipid Research Center, Im Neuenheimer Feld 515, 69120 Heidelberg, Germany
| | - Peter van Hoogevest
- Phospholipid Research Center, Im Neuenheimer Feld 515, 69120 Heidelberg, Germany
| | - Simon Drescher
- Phospholipid Research Center, Im Neuenheimer Feld 515, 69120 Heidelberg, Germany.
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2
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Bril’kov MS, Stenbakk V, Jakubec M, Vasskog T, Kristoffersen T, Cavanagh JP, Ericson JU, Isaksson J, Flaten GE. Bacterial extracellular vesicles: towards realistic models for bacterial membranes in molecular interaction studies by surface plasmon resonance. Front Mol Biosci 2023; 10:1277963. [PMID: 38152113 PMCID: PMC10751319 DOI: 10.3389/fmolb.2023.1277963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/01/2023] [Indexed: 12/29/2023] Open
Abstract
One way to mitigate the ongoing antimicrobial resistance crisis is to discover and develop new classes of antibiotics. As all antibiotics at some point need to either cross or just interact with the bacterial membrane, there is a need for representative models of bacterial membranes and efficient methods to characterize the interactions with novel molecules -both to generate new knowledge and to screen compound libraries. Since the bacterial cell envelope is a complex assembly of lipids, lipopolysaccharides, membrane proteins and other components, constructing relevant synthetic liposome-based models of the membrane is both difficult and expensive. We here propose to let the bacteria do the hard work for us. Bacterial extracellular vesicles (bEVs) are naturally secreted by Gram-negative and Gram-positive bacteria, playing a role in communication between bacteria, as virulence factors, molecular transport or being a part of the antimicrobial resistance mechanism. bEVs consist of the bacterial outer membrane and thus inherit many components and properties of the native outer cell envelope. In this work, we have isolated and characterized bEVs from one Escherichia coli mutant and three clinical strains of the ESKAPE pathogens Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. The bEVs were shown to be representative models for the bacterial membrane in terms of lipid composition with speciesstrain specific variations. The bEVs were further used to probe the interactions between bEV and antimicrobial peptides (AMPs) as model compounds by Surface Plasmon Resonance (SPR) and provide proof-of-principle that bEVs can be used as an easily accessible and highly realistic model for the bacterial surface in interaction studies. This further enables direct monitoring of the effect induced by antibiotics, or the response to host-pathogen interactions.
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Affiliation(s)
- Maxim S. Bril’kov
- Drug Transport and Delivery Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT the Arctic University of Norway, Tromsø, Norway
| | - Victoria Stenbakk
- Drug Transport and Delivery Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT the Arctic University of Norway, Tromsø, Norway
| | - Martin Jakubec
- Chemical Synthesis and Analysis Research Group, Department of Chemistry, Faculty of Natural Sciences and Technology, UiT the Arctic University of Norway, Tromsø, Norway
| | - Terje Vasskog
- Natural Products and Medicinal Chemistry Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT the Arctic University of Norway, Tromsø, Norway
| | - Tone Kristoffersen
- Chemical Synthesis and Analysis Research Group, Department of Chemistry, Faculty of Natural Sciences and Technology, UiT the Arctic University of Norway, Tromsø, Norway
| | - Jorunn Pauline Cavanagh
- Pediatric Research Group, Department of Clinical Medicine, Faculty of Health Sciences, UiT the Arctic University of Norway, Tromsø, Norway
| | - Johanna U. Ericson
- Research Group for Host Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT the Arctic University of Norway, Tromsø, Norway
| | - Johan Isaksson
- Chemical Synthesis and Analysis Research Group, Department of Chemistry, Faculty of Natural Sciences and Technology, UiT the Arctic University of Norway, Tromsø, Norway
- Natural Products and Medicinal Chemistry Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT the Arctic University of Norway, Tromsø, Norway
| | - Gøril Eide Flaten
- Drug Transport and Delivery Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT the Arctic University of Norway, Tromsø, Norway
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Machin JM, Kalli AC, Ranson NA, Radford SE. Protein-lipid charge interactions control the folding of outer membrane proteins into asymmetric membranes. Nat Chem 2023; 15:1754-1764. [PMID: 37710048 PMCID: PMC10695831 DOI: 10.1038/s41557-023-01319-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 08/08/2023] [Indexed: 09/16/2023]
Abstract
Biological membranes consist of two leaflets of phospholipid molecules that form a bilayer, each leaflet comprising a distinct lipid composition. This asymmetry is created and maintained in vivo by dedicated biochemical pathways, but difficulties in creating stable asymmetric membranes in vitro have restricted our understanding of how bilayer asymmetry modulates the folding, stability and function of membrane proteins. In this study, we used cyclodextrin-mediated lipid exchange to generate liposomes with asymmetric bilayers and characterize the stability and folding kinetics of two bacterial outer membrane proteins (OMPs), OmpA and BamA. We found that excess negative charge in the outer leaflet of a liposome impedes their insertion and folding, while excess negative charge in the inner leaflet accelerates their folding relative to symmetric liposomes with the same membrane composition. Using molecular dynamics, mutational analysis and bioinformatics, we identified a positively charged patch critical for folding and stability. These results rationalize the well-known 'positive-outside' rule of OMPs and suggest insights into the mechanisms that drive OMP folding and assembly in vitro and in vivo.
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Affiliation(s)
- Jonathan M Machin
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Antreas C Kalli
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK.
| | - Neil A Ranson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
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4
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Krok E, Stephan M, Dimova R, Piatkowski L. Tunable biomimetic bacterial membranes from binary and ternary lipid mixtures and their application in antimicrobial testing. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184194. [PMID: 37328023 DOI: 10.1016/j.bbamem.2023.184194] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/05/2023] [Accepted: 06/08/2023] [Indexed: 06/18/2023]
Abstract
The reconstruction of accurate yet simplified mimetic models of cell membranes is a very challenging goal of synthetic biology. To date, most of the research focuses on the development of eukaryotic cell membranes, while reconstitution of their prokaryotic counterparts has not been fully addressed, and the proposed models do not reflect well the complexity of bacterial cell envelopes. Here, we describe the reconstitution of biomimetic bacterial membranes with an increasing level of complexity, developed from binary and ternary lipid mixtures. Giant unilamellar vesicles composed of phosphatidylcholine (PC) and phosphatidylethanolamine (PE); PC and phosphatidylglycerol (PG); PE and PG; PE, PG and cardiolipin (CA) at varying molar ratios were successfully prepared by the electroformation method. Each of the proposed mimetic models focuses on reproducing specific membrane features such as membrane charge, curvature, leaflets asymmetry, or the presence of phase separation. GUVs were characterized in terms of size distribution, surface charge, and lateral organization. Finally, the developed models were tested against the lipopeptide antibiotic daptomycin. The obtained results showed a clear dependency of daptomycin binding efficiency on the amount of negatively charged lipid species present in the membrane. We anticipate that the models proposed here can be applied not only in antimicrobial testing but also serve as platforms for studying fundamental biological processes in bacteria as well as their interaction with physiologically relevant biomolecules.
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Affiliation(s)
- Emilia Krok
- Poznan University of Technology, Faculty of Materials Engineering and Technical Physics, Institute of Physics, Piotrowo 3, 60-965 Poznan, Poland; Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany.
| | - Mareike Stephan
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany.
| | - Lukasz Piatkowski
- Poznan University of Technology, Faculty of Materials Engineering and Technical Physics, Institute of Physics, Piotrowo 3, 60-965 Poznan, Poland
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5
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Rath P, Hermann A, Schaefer R, Agustoni E, Vonach JM, Siegrist M, Miscenic C, Tschumi A, Roth D, Bieniossek C, Hiller S. High-throughput screening of BAM inhibitors in native membrane environment. Nat Commun 2023; 14:5648. [PMID: 37704632 PMCID: PMC10499997 DOI: 10.1038/s41467-023-41445-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 09/02/2023] [Indexed: 09/15/2023] Open
Abstract
The outer membrane insertase of Gram-negative bacteria, BAM, is a key target for urgently needed novel antibiotics. Functional reconstitutions of BAM have so far been limited to synthetic membranes and with low throughput capacity for inhibitor screening. Here, we describe a BAM functional assay in native membrane environment capable of high-throughput screening. This is achieved by employing outer membrane vesicles (OMVs) to present BAM directly in native membranes. Refolding of the model substrate OmpT by BAM was possible from the chaperones SurA and Skp, with the required SurA concentration three times higher than Skp. In the OMVs, the antibiotic darobactin had a tenfold higher potency than in synthetic membranes, highlighting the need for native conditions in antibiotics development. The assay is successfully miniaturized for 1536-well plates and upscaled using large scale fermentation, resulting in high-throughput capacities to screen large commercial compound libraries. Our OMV-based assay thus lays the basis for discovery, hit validation and lead expansion of antibiotics targeting BAM.
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Affiliation(s)
- Parthasarathi Rath
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland
| | - Adrian Hermann
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Ramona Schaefer
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Elia Agustoni
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland
| | - Jean-Marie Vonach
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Martin Siegrist
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Christian Miscenic
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Andreas Tschumi
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Doris Roth
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Christoph Bieniossek
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Sebastian Hiller
- Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland.
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Nandi S, Nair KS, Bajaj H. Bacterial Outer-Membrane-Mimicking Giant Unilamellar Vesicle Model for Detecting Antimicrobial Permeability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5891-5900. [PMID: 37036429 DOI: 10.1021/acs.langmuir.3c00378] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The construction of bacterial outer membrane models with native lipids like lipopolysaccharide (LPS) is a barrier to understanding antimicrobial permeability at the membrane interface. Here, we engineer bacterial outer membrane (OM)-mimicking giant unilamellar vesicles (GUVs) by constituting LPS under different pH conditions and assembled GUVs with controlled dimensions. We quantify the LPS reconstituted in GUV membranes and reveal their arrangement in the leaflets of the vesicles. Importantly, we demonstrate the applications of OM vesicles by exploring antimicrobial permeability activity across membranes. Model peptides, melittin and magainin-2, are examined where both peptides exhibit lower membrane activity in OM vesicles than vesicles devoid of LPS. Our findings reveal the mode of action of antimicrobial peptides in bacterial-membrane-mimicking models. Notably, the critical peptide concentration required to elicit activity on model membranes correlates with the cell inhibitory concentrations that revalidate our models closely mimic bacterial membranes. In conclusion, we provide an OM-mimicking model capable of quantifying antimicrobial permeability across membranes.
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Affiliation(s)
- Samir Nandi
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India
| | - Karthika S Nair
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India
| | - Harsha Bajaj
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India
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7
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Stephan MS, Dunsing V, Pramanik S, Chiantia S, Barbirz S, Robinson T, Dimova R. Biomimetic asymmetric bacterial membranes incorporating lipopolysaccharides. Biophys J 2022:S0006-3495(22)03927-3. [PMID: 36523159 DOI: 10.1016/j.bpj.2022.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/30/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Gram-negative bacteria are equipped with a cell wall that contains a complex matrix of lipids, proteins, and glycans, which form a rigid layer protecting bacteria from the environment. Major components of this outer membrane are the high-molecular weight and amphiphilic lipopolysaccharides (LPSs). They form the extracellular part of a heterobilayer with phospholipids. Understanding LPS properties within the outer membrane is therefore important to develop new antimicrobial strategies. Model systems, such as giant unilamellar vesicles (GUVs), provide a suitable platform for exploring membrane properties and interactions. However, LPS molecules contain large polysaccharide parts that confer high water solubility, which makes LPS incorporation in artificial membranes difficult; this hindrance is exacerbated for LPS with long polysaccharide chains, i.e., the smooth LPS. Here, a novel emulsification step of the inverted emulsion method is introduced to incorporate LPS in the outer or the inner leaflet of GUVs, exclusively. We developed an approach to determine the LPS content on individual GUVs and quantify membrane asymmetry. The asymmetric membranes with outer leaflet LPS show incorporations of 1-16 mol % smooth LPS (corresponding to 16-79 wt %), while vesicles with inner leaflet LPS reach coverages of 2-7 mol % smooth LPS (28-60 wt %). Diffusion coefficient measurements in the obtained GUVs showed that increasing LPS concentrations in the membranes resulted in decreased diffusivity.
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Affiliation(s)
| | - Valentin Dunsing
- Aix-Marseille Université, CNRS, IBDM, Turing Center for Living Systems, Marseille, France; University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Germany
| | - Shreya Pramanik
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Salvatore Chiantia
- University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Germany
| | - Stefanie Barbirz
- Department Humanmedizin, MSB Medical School Berlin, Berlin, Germany
| | - Tom Robinson
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
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8
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Panda G, Dash S, Sahu SK. Harnessing the Role of Bacterial Plasma Membrane Modifications for the Development of Sustainable Membranotropic Phytotherapeutics. MEMBRANES 2022; 12:914. [PMID: 36295673 PMCID: PMC9612325 DOI: 10.3390/membranes12100914] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/08/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Membrane-targeted molecules such as cationic antimicrobial peptides (CAMPs) are amongst the most advanced group of antibiotics used against drug-resistant bacteria due to their conserved and accessible targets. However, multi-drug-resistant bacteria alter their plasma membrane (PM) lipids, such as lipopolysaccharides (LPS) and phospholipids (PLs), to evade membrane-targeted antibiotics. Investigations reveal that in addition to LPS, the varying composition and spatiotemporal organization of PLs in the bacterial PM are currently being explored as novel drug targets. Additionally, PM proteins such as Mla complex, MPRF, Lpts, lipid II flippase, PL synthases, and PL flippases that maintain PM integrity are the most sought-after targets for development of new-generation drugs. However, most of their structural details and mechanism of action remains elusive. Exploration of the role of bacterial membrane lipidome and proteome in addition to their organization is the key to developing novel membrane-targeted antibiotics. In addition, membranotropic phytochemicals and their synthetic derivatives have gained attractiveness as popular herbal alternatives against bacterial multi-drug resistance. This review provides the current understanding on the role of bacterial PM components on multidrug resistance and their targeting with membranotropic phytochemicals.
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Affiliation(s)
- Gayatree Panda
- Department of Biotechnology, Maharaja Sriram Chandra Bhanjadeo University (Erstwhile: North Orissa University), Baripada 757003, India
| | - Sabyasachi Dash
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Santosh Kumar Sahu
- Department of Biotechnology, Maharaja Sriram Chandra Bhanjadeo University (Erstwhile: North Orissa University), Baripada 757003, India
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9
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Li S, Ren R, Lyu L, Song J, Wang Y, Lin TW, Brun AL, Hsu HY, Shen HH. Solid and Liquid Surface-Supported Bacterial Membrane Mimetics as a Platform for the Functional and Structural Studies of Antimicrobials. MEMBRANES 2022; 12:membranes12100906. [PMID: 36295664 PMCID: PMC9609327 DOI: 10.3390/membranes12100906] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/05/2022] [Accepted: 09/13/2022] [Indexed: 06/02/2023]
Abstract
Increasing antibiotic resistance has provoked the urgent need to investigate the interactions of antimicrobials with bacterial membranes. The reasons for emerging antibiotic resistance and innovations in novel therapeutic approaches are highly relevant to the mechanistic interactions between antibiotics and membranes. Due to the dynamic nature, complex compositions, and small sizes of native bacterial membranes, bacterial membrane mimetics have been developed to allow for the in vitro examination of structures, properties, dynamics, and interactions. In this review, three types of model membranes are discussed: monolayers, supported lipid bilayers, and supported asymmetric bilayers; this review highlights their advantages and constraints. From monolayers to asymmetric bilayers, biomimetic bacterial membranes replicate various properties of real bacterial membranes. The typical synthetic methods for fabricating each model membrane are introduced. Depending on the properties of lipids and their biological relevance, various lipid compositions have been used to mimic bacterial membranes. For example, mixtures of phosphatidylethanolamines (PE), phosphatidylglycerols (PG), and cardiolipins (CL) at various molar ratios have been used, approaching actual lipid compositions of Gram-positive bacterial membranes and inner membranes of Gram-negative bacteria. Asymmetric lipid bilayers can be fabricated on solid supports to emulate Gram-negative bacterial outer membranes. To probe the properties of the model bacterial membranes and interactions with antimicrobials, three common characterization techniques, including quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance (SPR), and neutron reflectometry (NR) are detailed in this review article. Finally, we provide examples showing that the combination of bacterial membrane models and characterization techniques is capable of providing crucial information in the design of new antimicrobials that combat bacterial resistance.
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Affiliation(s)
- Shiqi Li
- Department of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Ruohua Ren
- Department of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Letian Lyu
- Department of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Jiangning Song
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Yajun Wang
- College of Chemistry & Materials Engineering, Wenzhou University, Wenzhou 325035, China
| | - Tsung-Wu Lin
- Department of Chemistry, Tunghai University, No. 1727, Sec. 4, Taiwan Boulevard, Xitun District, Taichung 40704, Taiwan
| | - Anton Le Brun
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Hsien-Yi Hsu
- Department of Materials Science and Engineering, School of Energy and Environment, City University of Hong Kong, Kowloon Tong, Hong Kong, China
| | - Hsin-Hui Shen
- Department of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
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10
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Loss of β-Ketoacyl Acyl Carrier Protein Synthase III Activity Restores Multidrug-Resistant Escherichia coli Sensitivity to Previously Ineffective Antibiotics. mSphere 2022; 7:e0011722. [PMID: 35574679 PMCID: PMC9241538 DOI: 10.1128/msphere.00117-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gram-negative pathogens are a major concern for global public health due to increasing rates of antibiotic resistance and the lack of new drugs. A major contributing factor toward antibiotic resistance in Gram-negative bacteria is their formidable outer membrane, which acts as a permeability barrier preventing many biologically active antimicrobials from reaching the intracellular targets and thus limiting their efficacy.
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11
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Abstract
AbstractThe 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.
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12
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Paracini N, Schneck E, Imberty A, Micciulla S. Lipopolysaccharides at Solid and Liquid Interfaces: Models for Biophysical Studies of the Gram-negative Bacterial Outer Membrane. Adv Colloid Interface Sci 2022; 301:102603. [PMID: 35093846 DOI: 10.1016/j.cis.2022.102603] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 11/18/2022]
Abstract
Lipopolysaccharides (LPSs) are a constitutive element of the cell envelope of Gram-negative bacteria, representing the main lipid in the external leaflet of their outer membrane (OM) lipid bilayer. These unique surface-exposed glycolipids play a central role in the interactions of Gram-negative organisms with their surrounding environment and represent a key element for protection against antimicrobials and the development of antibiotic resistance. The biophysical investigation of a wide range of different types of in vitro model membranes containing reconstituted LPS has revealed functional and structural properties of these peculiar membrane lipids, providing molecular-level details of their interaction with antimicrobial compounds. LPS assemblies reconstituted at interfaces represent a versatile tool to study the properties of the Gram-negative OM by exploiting several surface-sensitive techniques, in particular X-ray and neutron scattering, which can probe the structure of thin films with sub-nanometer resolution. This review provides an overview of different approaches employed to investigate structural and biophysical properties of LPS, focusing on studies on Langmuir monolayers of LPS at the air/liquid interface and a range of supported LPS-containing model membranes reconstituted at solid/liquid interfaces.
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Affiliation(s)
| | - Emanuel Schneck
- Physics Departent, Technische Universität Darmstadt, Darmstadt, Germany
| | - Anne Imberty
- Université Grenoble Alpes, CNRS, CERMAV, Grenoble, France
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13
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MacDermott-Opeskin HI, Gupta V, O’Mara ML. Lipid-mediated antimicrobial resistance: a phantom menace or a new hope? Biophys Rev 2022; 14:145-162. [PMID: 35251360 PMCID: PMC8880301 DOI: 10.1007/s12551-021-00912-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/14/2021] [Indexed: 02/06/2023] Open
Abstract
Abstract The proposition of a post-antimicrobial era is all the more realistic with the continued rise of antimicrobial resistance. The development of new antimicrobials is failing to counter the ever-increasing rates of bacterial antimicrobial resistance. This necessitates novel antimicrobials and drug targets. The bacterial cell membrane is an essential and highly conserved cellular component in bacteria and acts as the primary barrier for entry of antimicrobials into the cell. Although previously under-exploited as an antimicrobial target, the bacterial cell membrane is attractive for the development of novel antimicrobials due to its importance in pathogen viability. Bacterial cell membranes are diverse assemblies of macromolecules built around a central lipid bilayer core. This lipid bilayer governs the overall membrane biophysical properties and function of its membrane-embedded proteins. This mini-review will outline the mechanisms by which the bacterial membrane causes and controls resistance, with a focus on alterations in the membrane lipid composition, chemical modification of constituent lipids, and the efflux of antimicrobials by membrane-embedded efflux systems. Thorough insight into the interplay between membrane-active antimicrobials and lipid-mediated resistance is needed to enable the rational development of new antimicrobials. In particular, the union of computational approaches and experimental techniques for the development of innovative and efficacious membrane-active antimicrobials is explored.
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Affiliation(s)
- Hugo I. MacDermott-Opeskin
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Vrinda Gupta
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Megan L. O’Mara
- Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
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Nair KS, Raj NB, Nampoothiri KM, Mohanan G, Acosta-Gutiérrez S, Bajaj H. Curved membrane structures induced by native lipids in giant vesicles. J Colloid Interface Sci 2021; 611:397-407. [PMID: 34963074 DOI: 10.1016/j.jcis.2021.12.098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
Abstract
Native lipids in cell-membrane support crucial functions like intercell communication via their ability to deform into curved membrane structures. Cell membrane mimicking Giant unilamellar vesicles (GUV) is imperative in understanding native lipid's role in membrane transformation however remains challenging to assemble. We construct two giant vesicle models mimicking bacterial inner-membrane (IM) and outer-membrane (OM) under physiological conditions using single-step gel-assisted lipid swelling. IM vesicles composed of native bacterial lipids undergo small-scale membrane remodeling into bud and short-nanotube structures. In contrast, OM vesicles asymmetrically assembled from Lipopolysaccharide (LPS) and bacterial lipids underwent global membrane deformation under controlled osmotic stress. Remarkably, highly-curved structures mimicking cell-membrane architectures, including daughter vesicle networks interconnected by necks and nano-tubes ranging from micro to nanoscale, are generated in OM vesicles at osmotic stress comparable to that applied in IM vesicles. Further, we provide a quantitative description of the membrane structures by experimentally determining membrane elastic parameters, i.e., neck curvature and bending rigidity. We can conclude that a larger spontaneous curvature estimated from the neck curvature and softer membranes in OM vesicles is responsible for large-scale deformation compared to IM vesicles. Our findings will help comprehend the shape dynamics of complex native bacterial lipid membranes.
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Affiliation(s)
- Karthika S Nair
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India
| | - Neethu B Raj
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India
| | - K Madhavan Nampoothiri
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India
| | - Gayathri Mohanan
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India
| | - Silvia Acosta-Gutiérrez
- Department of Chemistry, Institute of Structural and Molecular Biology, University College London, UK.
| | - Harsha Bajaj
- Microbial Processes and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695019, Kerala, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad 201002, India.
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15
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Kotlyarov S, Kotlyarova A. Molecular Mechanisms of Lipid Metabolism Disorders in Infectious Exacerbations of Chronic Obstructive Pulmonary Disease. Int J Mol Sci 2021; 22:7634. [PMID: 34299266 PMCID: PMC8308003 DOI: 10.3390/ijms22147634] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/13/2021] [Accepted: 07/15/2021] [Indexed: 02/06/2023] Open
Abstract
Exacerbations largely determine the character of the progression and prognosis of chronic obstructive pulmonary disease (COPD). Exacerbations are connected with changes in the microbiological landscape in the bronchi due to a violation of their immune homeostasis. Many metabolic and immune processes involved in COPD progression are associated with bacterial colonization of the bronchi. The objective of this review is the analysis of the molecular mechanisms of lipid metabolism and immune response disorders in the lungs in COPD exacerbations. The complex role of lipid metabolism disorders in the pathogenesis of some infections is only beginning to be understood, however, there are already fewer and fewer doubts even now about its significance both in the pathogenesis of infectious exacerbations of COPD and in general in the progression of the disease. It is shown that the lipid rafts of the plasma membranes of cells are involved in many processes related to the detection of pathogens, signal transduction, the penetration of pathogens into the cell. Smoking disrupts the normally proceeded processes of lipid metabolism in the lungs, which is a part of the COPD pathogenesis.
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Affiliation(s)
- Stanislav Kotlyarov
- Department of Nursing, Ryazan State Medical University, 390026 Ryazan, Russia
| | - Anna Kotlyarova
- Department of Pharmacology and Pharmacy, Ryazan State Medical University, 390026 Ryazan, Russia;
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