1
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Kaur M, Mingeot-Leclercq MP. Maintenance of bacterial outer membrane lipid asymmetry: insight into MlaA. BMC Microbiol 2024; 24:186. [PMID: 38802775 PMCID: PMC11131202 DOI: 10.1186/s12866-023-03138-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 11/29/2023] [Indexed: 05/29/2024] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria acts as an effective barrier to protect against toxic compounds. By nature, the OM is asymmetric with the highly packed lipopolysaccharide (LPS) at the outer leaflet and glycerophospholipids at the inner leaflet. OM asymmetry is maintained by the Mla system, in which is responsible for the retrograde transport of glycerophospholipids from the OM to the inner membrane. This system is comprised of six Mla proteins, including MlaA, an OM lipoprotein involved in the removal of glycerophospholipids that are mis-localized at the outer leaflet of the OM. Interestingly, MlaA was initially identified - and called VacJ - based on its role in the intracellular spreading of Shigella flexneri.Many open questions remain with respect to the Mla system and the mechanism involved in the translocation of mislocated glycerophospholipids at the outer leaflet of the OM, by MlaA. After summarizing the current knowledge on MlaA, we focus on the impact of mlaA deletion on OM lipid composition and biophysical properties of the OM. How changes in OM lipid composition and biophysical properties can impact the generation of membrane vesicles and membrane permeability is discussed. Finally, we explore whether and how MlaA might be a candidate for improving the activity of antibiotics and as a vaccine candidate.Efforts dedicated to understanding the relationship between the OM lipid composition and the mechanical strength of the bacterial envelope and, in turn, how such properties act against external stress, are needed for the design of new targets or drugs for Gram-negative infections.
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Affiliation(s)
- M Kaur
- Louvain Drug Research Institute, Université catholique de Louvain, Unité de Pharmacologie cellulaire et moléculaire, B1.73.05; 73 Av E. Mounier, Brussels, 1200, Belgium
| | - M-P Mingeot-Leclercq
- Louvain Drug Research Institute, Université catholique de Louvain, Unité de Pharmacologie cellulaire et moléculaire, B1.73.05; 73 Av E. Mounier, Brussels, 1200, Belgium.
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2
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Sharma P, Vaiwala R, Gopinath AK, Chockalingam R, Ayappa KG. Structure of the Bacterial Cell Envelope and Interactions with Antimicrobials: Insights from Molecular Dynamics Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:7791-7811. [PMID: 38451026 DOI: 10.1021/acs.langmuir.3c03474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Bacteria have evolved over 3 billion years, shaping our intrinsic and symbiotic coexistence with these single-celled organisms. With rising populations of drug-resistant strains, the search for novel antimicrobials is an ongoing area of research. Advances in high-performance computing platforms have led to a variety of molecular dynamics simulation strategies to study the interactions of antimicrobial molecules with different compartments of the bacterial cell envelope of both Gram-positive and Gram-negative species. In this review, we begin with a detailed description of the structural aspects of the bacterial cell envelope. Simulations concerned with the transport and associated free energy of small molecules and ions through the outer membrane, peptidoglycan, inner membrane and outer membrane porins are discussed. Since surfactants are widely used as antimicrobials, a section is devoted to the interactions of surfactants with the cell wall and inner membranes. The review ends with a discussion on antimicrobial peptides and the insights gained from the molecular simulations on the free energy of translocation. Challenges involved in developing accurate molecular models and coarse-grained strategies that provide a trade-off between atomic details with a gain in sampling time are highlighted. The need for efficient sampling strategies to obtain accurate free energies of translocation is also discussed. Molecular dynamics simulations have evolved as a powerful tool that can potentially be used to design and develop novel antimicrobials and strategies to effectively treat bacterial infections.
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Affiliation(s)
- Pradyumn Sharma
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - Rakesh Vaiwala
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - Amar Krishna Gopinath
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - Rajalakshmi Chockalingam
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
| | - K Ganapathy Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India, 560012
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3
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Gasanov V, Vorotelyak E, Vasiliev A. Expression of the Antimicrobial Peptide SE-33-A2P, a Modified Analog of Cathelicidin, and an Analysis of Its Properties. Antibiotics (Basel) 2024; 13:190. [PMID: 38391576 PMCID: PMC10886013 DOI: 10.3390/antibiotics13020190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 02/03/2024] [Accepted: 02/06/2024] [Indexed: 02/24/2024] Open
Abstract
In this study, we developed a method for the expression of the antimicrobial peptide SE-33-A2P in E. coli bacterial cells. The SE-33-A2P peptide consists of A2P and SE-33 peptides and is a retro analog of cathelicidin possessing antimicrobial activity against both Gram-positive and Gram-negative bacteria. Furthermore, the A2P peptide is a self-cleaving peptide. For an efficient expression of the SE-33-A2P peptide, a gene encoding several repetitive sequences of the SE-33 peptide separated by A2P sequences was created. The gene was cloned into a plasmid, with which E. coli cells were transformed. An induction of the product expression was carried out by IPTG after the cell culture gained high density. The inducible expression product, due to the properties of the A2P peptide, was cleaved in the cell into SE-33-A2P peptides. As the next step, the SE-33-A2P peptide was purified using filtration and chromatography. Its activity against both Gram-positive and Gram-negative bacteria, including antibiotic-resistant bacteria, was proved. The developed approach for obtaining a prokaryotic system for the expression of a highly active antimicrobial peptide expands the opportunities for producing antimicrobial peptides via industrial methods.
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Affiliation(s)
- Vagif Gasanov
- Laboratory of Cell Biology, N.K. Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Vavilov Str. 26, 119334 Moscow, Russia
| | - Ekaterina Vorotelyak
- Laboratory of Cell Biology, N.K. Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Vavilov Str. 26, 119334 Moscow, Russia
| | - Andrey Vasiliev
- Laboratory of Cell Biology, N.K. Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Vavilov Str. 26, 119334 Moscow, Russia
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4
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Velayatipour F, Tarrahimofrad H, Zamani J, Fotouhi F, Aminzadeh S. In-vitro antimicrobial activity of AF-DP protein and in-silico approach of cell membrane disruption. J Biomol Struct Dyn 2024:1-18. [PMID: 38319027 DOI: 10.1080/07391102.2024.2308763] [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: 08/31/2023] [Accepted: 01/14/2024] [Indexed: 02/07/2024]
Abstract
Microbial resistance against common antibiotics has become one of the most serious threats to human health. The increasing statistics on this problem show the necessity of finding a way to deal with it. In recent years, antimicrobial peptides with unique properties and the capability of targeting a wide range of pathogens, have been considered as a potential for replacing common antibiotics. A small chitin-binding protein with anticandidal activity was isolated from Moringa oleifera seeds by Neto and colleagues in 2017, which very much resembled antimicrobial peptides. In this study, the antimicrobial protein 'AF-DP' was identified and characterized. AF-DP was heterologously expressed, purified, and characterized, and its 3D structure was predicted. Six molecular dynamic simulations were performed to investigate how the protein interacts with Gram-negative inner and outer, Gram-positive, fungal, cancerous, and normal mammalian membranes. Also, its antimicrobial and anticancer activity was assessed in vitro via minimum inhibition concentration (MIC) and MTT assays, respectively. This protein with 111 amino acids and a total net charge (of 10.5) has been predicted to be mainly composed of alpha helix and random coils. Its MIC affecting the growth of Escherichia coli, Staphylococcus aureus, and Candida albicans was 30 µg/ml, 100 µg/ml, and 100 µg/ml, respectively; AF-DP showed anticancer activity against MCF-7 breast cancer cell line. Scanning electron microscopic analysis confirmed the creation of pores and scratches on the surface of the bacterial membrane. The results of this research show that AF-DP can be a candidate for the production of new drugs as an AMP with antimicrobial activity.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Fatemeh Velayatipour
- Bioprocess Engineering Group, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Hossein Tarrahimofrad
- Bioprocess Engineering Group, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Javad Zamani
- Bioprocess Engineering Group, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Fatemeh Fotouhi
- Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saeed Aminzadeh
- Bioprocess Engineering Group, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
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5
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Maher C, Hassan KA. The Gram-negative permeability barrier: tipping the balance of the in and the out. mBio 2023; 14:e0120523. [PMID: 37861328 PMCID: PMC10746187 DOI: 10.1128/mbio.01205-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023] Open
Abstract
Gram-negative bacteria are intrinsically resistant to many antibiotics, due in large part to the permeability barrier formed by their cell envelope. The complex and synergistic interplay of the two Gram-negative membranes and active efflux prevents the accumulation of a diverse range of compounds that are effective against Gram-positive bacteria. A lack of detailed information on how components of the cell envelope contribute to this has been identified as a key barrier to the rational development of new antibiotics with efficacy against Gram-negative species. This review describes the current understanding of the role of the different components of the Gram-negative cell envelope in preventing compound accumulation and the state of efforts to describe properties that allow compounds to overcome this barrier and apply them to the development of new broad-spectrum antibiotics.
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Affiliation(s)
- Claire Maher
- College of Engineering, Science and Environment, University of Newcastle, Newcastle, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
| | - Karl A. Hassan
- College of Engineering, Science and Environment, University of Newcastle, Newcastle, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
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6
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Lipid-A-dependent and cholesterol-dependent dynamics properties of liposomes from gram-negative bacteria in ESKAPE. Sci Rep 2022; 12:19474. [PMID: 36376343 PMCID: PMC9663605 DOI: 10.1038/s41598-022-22886-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 10/20/2022] [Indexed: 11/16/2022] Open
Abstract
AntiMicrobial Resistance (AMR) is a worldwide health emergency. ESKAPE pathogens include the most relevant AMR bacterial families. In particular, Gram-negative bacteria stand out due to their cell envelope complexity which exhibits strong resistance to antimicrobials. A key element for AMR is the chemical structure of lipid A, modulating the physico-chemical properties of the membrane and permeability to antibiotics. Liposomes are used as models of bacterial membrane infective vesicles. In this work, coarse-grained molecular dynamics simulations were used to model liposomes from ESKAPE Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa). We captured the role of lipid A, cardiolipin and cholesterol on liposome morphology and physico-chemical properties. Additionally, the reported antimicrobial peptides Cecropin B1, JB95, and PTCDA1-kf, were used to unveil their implications on membrane disruption. This study opens a promising starting point to understand molecular keys of bacterial membranes and to promote the discovery of new antimicrobials to overcome AMR.
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7
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Lysozyme and Its Application as Antibacterial Agent in Food Industry. Molecules 2022; 27:molecules27196305. [PMID: 36234848 PMCID: PMC9572377 DOI: 10.3390/molecules27196305] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/18/2022] [Accepted: 09/21/2022] [Indexed: 11/17/2022] Open
Abstract
Lysozymes are hydrolytic enzymes characterized by their ability to cleave the β-(1,4)-glycosidic bonds in peptidoglycan, a major structural component of the bacterial cell wall. This hydrolysis action compromises the integrity of the cell wall, causing the lysis of bacteria. For more than 80 years, its role of antibacterial defense in animals has been renowned, and it is also used as a preservative in foods and pharmaceuticals. In order to improve the antimicrobial efficacy of lysozyme, extensive research has been intended for its modifications. This manuscript reviews the natural antibiotic compound lysozyme with reference to its catalytic and non-catalytic mode of antibacterial action, lysozyme types, susceptibility and resistance of bacteria, modification of lysozyme molecules, and its applications in the food industry.
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8
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Jiang X, Han M, Tran K, Patil NA, Ma W, Roberts KD, Xiao M, Sommer B, Schreiber F, Wang L, Velkov T, Li J. An Intelligent Strategy with All-Atom Molecular Dynamics Simulations for the Design of Lipopeptides against Multidrug-Resistant Pseudomonas aeruginosa. J Med Chem 2022; 65:10001-10013. [PMID: 35786900 DOI: 10.1021/acs.jmedchem.2c00657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Multidrug-resistant Gram-negative bacteria seriously threaten modern medicine due to the lack of efficacious therapeutic options. Their outer membrane (OM) is an essential protective fortress to exclude many antibiotics. Unfortunately, current structural biology methods are not able to resolve the membrane structure and it is difficult to examine the specific interaction between the OM and small molecules. These limitations hinder mechanistic understanding of antibiotic penetration through the OM and antibiotic discovery. Here, we developed biologically relevant OM models by quantitatively determining membrane lipidomics of Pseudomonas aeruginosa and elucidated how lipopolysaccharide modifications and OM vesicles mediated resistance to polymyxins. Supported by chemical biology and pharmacological assays, our multiscale molecular dynamics simulations provide an intelligent platform to quantify the membrane-penetrating thermodynamics of peptides and predict their antimicrobial activity. Through experimental validations with our in-house polymyxin analogue library, our computational strategy may have significant potential in accelerating the discovery of lipopeptides against bacterial "superbugs".
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Affiliation(s)
- Xukai Jiang
- National Glycoengineering Research Center, Shandong University, Qingdao 266237, China
| | - Meiling Han
- Biomedicine Discovery Institute, Infection Program and Department of Microbiology, Monash University, Melbourne 3800, Australia
| | - Kevin Tran
- Biomedicine Discovery Institute, Infection Program and Department of Microbiology, Monash University, Melbourne 3800, Australia
| | - Nitin A Patil
- Biomedicine Discovery Institute, Infection Program and Department of Microbiology, Monash University, Melbourne 3800, Australia
| | - Wendong Ma
- Biomedicine Discovery Institute, Infection Program and Department of Microbiology, Monash University, Melbourne 3800, Australia
| | - Kade D Roberts
- Biomedicine Discovery Institute, Infection Program and Department of Microbiology, Monash University, Melbourne 3800, Australia
| | - Min Xiao
- National Glycoengineering Research Center, Shandong University, Qingdao 266237, China
| | - Bjorn Sommer
- Department of Computer and Information Science, University of Konstanz, Konstanz 78457, Germany
| | - Falk Schreiber
- Department of Computer and Information Science, University of Konstanz, Konstanz 78457, Germany
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Tony Velkov
- Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne 3010, Australia
| | - Jian Li
- Biomedicine Discovery Institute, Infection Program and Department of Microbiology, Monash University, Melbourne 3800, Australia
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9
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Ginez LD, Osorio A, Vázquez-Ramírez R, Arenas T, Mendoza L, Camarena L, Poggio S. Changes in fluidity of the E. coli outer membrane in response to temperature, divalent cations and polymyxin-B show two different mechanisms of membrane fluidity adaptation. FEBS J 2022; 289:3550-3567. [PMID: 35038363 DOI: 10.1111/febs.16358] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/23/2021] [Accepted: 01/13/2022] [Indexed: 12/28/2022]
Abstract
The outer membrane (OM) is an essential component of the Gram-negative bacterial cell envelope. Restricted diffusion of integral OM proteins and lipopolysaccharide (LPS) that constitute the outer leaflet of the OM support a model in which the OM is in a semi-crystalline state. The low fluidity of the OM has been suggested to be an important property of this membrane that even contributes to cell rigidity. The LPS characteristics strongly determine the properties of the OM and the LPS layer fluidity has been measured using different techniques that require specific conditions or are technically challenging. Here, we characterize the Escherichia coli LPS fluidity by evaluating the lateral diffusion of the styryl dye FM4-64FX in fluorescence recovery after photobleaching experiments. This technique allowed us to determine the effect of different conditions and genetic backgrounds on the LPS fluidity. Our results show that a fraction of the LPS can slowly diffuse and that the fluidity of the LPS layer adapts by modifying the diffusion of the LPS and the fraction of mobile LPS molecules.
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Affiliation(s)
- Luis David Ginez
- Departamento Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
| | - Aurora Osorio
- Departamento Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
| | - Ricardo Vázquez-Ramírez
- Departamento Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
| | - Thelma Arenas
- Departamento Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
| | - Luis Mendoza
- Departamento Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
| | - Laura Camarena
- Departamento Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
| | - Sebastian Poggio
- Departamento Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México
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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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11
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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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12
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Murtha AN, Kazi MI, Schargel RD, Cross T, Fihn C, Cattoir V, Carlson EE, Boll JM, Dörr T. High-level carbapenem tolerance requires antibiotic-induced outer membrane modifications. PLoS Pathog 2022; 18:e1010307. [PMID: 35130322 PMCID: PMC8853513 DOI: 10.1371/journal.ppat.1010307] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 02/17/2022] [Accepted: 01/26/2022] [Indexed: 12/22/2022] Open
Abstract
Antibiotic tolerance is an understudied potential contributor to antibiotic treatment failure and the emergence of multidrug-resistant bacteria. The molecular mechanisms governing tolerance remain poorly understood. A prominent type of β-lactam tolerance relies on the formation of cell wall-deficient spheroplasts, which maintain structural integrity via their outer membrane (OM), an asymmetric lipid bilayer consisting of phospholipids on the inner leaflet and a lipid-linked polysaccharide (lipopolysaccharide, LPS) enriched in the outer monolayer on the cell surface. How a membrane structure like LPS, with its reliance on mere electrostatic interactions to maintain stability, is capable of countering internal turgor pressure is unknown. Here, we have uncovered a novel role for the PhoPQ two-component system in tolerance to the β-lactam antibiotic meropenem in Enterobacterales. We found that PhoPQ is induced by meropenem treatment and promotes an increase in 4-amino-4-deoxy-L-aminoarabinose [L-Ara4N] modification of lipid A, the membrane anchor of LPS. L-Ara4N modifications likely enhance structural integrity, and consequently tolerance to meropenem, in several Enterobacterales species. Importantly, mutational inactivation of the negative PhoPQ regulator mgrB (commonly selected for during clinical therapy with the last-resort antibiotic colistin, an antimicrobial peptide [AMP]) results in dramatically enhanced tolerance, suggesting that AMPs can collaterally select for meropenem tolerance via stable overactivation of PhoPQ. Lastly, we identify histidine kinase inhibitors (including an FDA-approved drug) that inhibit PhoPQ-dependent LPS modifications and consequently potentiate meropenem to enhance lysis of tolerant cells. In summary, our results suggest that PhoPQ-mediated LPS modifications play a significant role in stabilizing the OM, promoting survival when the primary integrity maintenance structure, the cell wall, is removed. Treating an infection with an antibiotic often fails, resulting in a tremendous public health burden. One understudied likely reason for treatment failure is the development of “antibiotic tolerance”, the ability of bacteria to survive normally lethal exposure to an antibiotic. Here, we describe a molecular mechanism promoting tolerance. A bacterial stress sensor (PhoPQ) is activated in response to antibiotic (meropenem) treatment and consequently strengthens a bacterial protective “shell” to enhance survival. We also identify inhibitors of this mechanism, opening the door to developing compounds that help antibiotics work better against tolerant bacteria.
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Affiliation(s)
- Andrew N. Murtha
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Microbiology, Cornell University, Ithaca, New York, United States of America
| | - Misha I. Kazi
- Department of Biology, University of Texas Arlington, Arlington, Texas, United States of America
| | - Richard D. Schargel
- Department of Biology, University of Texas Arlington, Arlington, Texas, United States of America
| | - Trevor Cross
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Microbiology, Cornell University, Ithaca, New York, United States of America
| | - Conrad Fihn
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Vincent Cattoir
- Department of Clinical Microbiology and National Reference Center for Antimicrobial Resistance (Lab Enterococci), Rennes University Hospital, Rennes, France; Inserm Unit U1230, University of Rennes 1, Rennes, France
| | - Erin E. Carlson
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Molecular Pharmacology and Therapeutics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Joseph M. Boll
- Department of Biology, University of Texas Arlington, Arlington, Texas, United States of America
- * E-mail: (JMB); (TD)
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Microbiology, Cornell University, Ithaca, New York, United States of America
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York, United States of America
- * E-mail: (JMB); (TD)
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13
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González-Fernández C, Bringas E, Oostenbrink C, Ortiz I. In silico investigation and surmounting of Lipopolysaccharide barrier in Gram-Negative Bacteria: How far has molecular dynamics Come? Comput Struct Biotechnol J 2022; 20:5886-5901. [PMID: 36382192 PMCID: PMC9636410 DOI: 10.1016/j.csbj.2022.10.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/24/2022] [Accepted: 10/24/2022] [Indexed: 11/29/2022] Open
Abstract
Lipopolysaccharide (LPS), a main component of the outer membrane of Gram-negative bacteria, has crucial implications on both antibiotic resistance and the overstimulation of the host innate immune system. Fighting against these global concerns calls for the molecular understanding of the barrier function and immunostimulatory ability of LPS. Molecular dynamics (MD) simulations have become an invaluable tool for uncovering important findings in LPS research. While the reach of MD simulations for investigating the immunostimulatory ability of LPS has been already outlined, little attention has been paid to the role of MD simulations for exploring its barrier function and synthesis. Herein, we give an overview about the impact of MD simulations on gaining insight into the shield role and synthesis pathway of LPS, which have attracted considerable attention to discover molecules able to surmount antibiotic resistance, either circumventing LPS defenses or disrupting its synthesis. We specifically focus on the enhanced sampling and free energy calculation methods that have been combined with MD simulations to address such research. We also highlight the use of special-purpose MD supercomputers, the importance of appropriate LPS and ions parameterization to obtain reliable results, and the complementary views that MD and wet-lab experiments provide. Thereby, this work, which covers the last five years of research, apart from outlining the phenomena and strategies that are being explored, evidences the valuable insights that are gained by MD, which may be useful to advance antibiotic design, and what the prospects of this in silico method could be in LPS research.
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Affiliation(s)
- Cristina González-Fernández
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005 Santander, Spain
| | - Eugenio Bringas
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005 Santander, Spain
| | - Chris Oostenbrink
- Institute for Molecular Modeling and Simulation, BOKU – University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Inmaculada Ortiz
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005 Santander, Spain
- Corresponding author.
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14
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Sun Y, Deng Z, Jiang X, Yuan B, Yang K. Interactions between polymyxin B and various bacterial membrane mimics: A molecular dynamics study. Colloids Surf B Biointerfaces 2021; 211:112288. [PMID: 34942463 DOI: 10.1016/j.colsurfb.2021.112288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/21/2021] [Accepted: 12/11/2021] [Indexed: 11/17/2022]
Abstract
Polymyxin B (PMB) is clinically used as a last-line therapy against life-threatening Gram-negative "superbugs". However, thorough understanding of the membrane actions of PMB at a molecular level is still lacking. In this work, a variety of bacterial membrane mimics with varying lipid compositions were built, and their interactions with PMB were systematically investigated using coarse-grained molecular dynamics simulation. PMB demonstrated characteristic preference to specific lipid species during its interaction with different membrane systems, such as the rough mutant lipipolysacchrides (Re LPS) preference in an outer membrane (OM) or the cardiolipin and POPG affinity in an inner membrane (IM). As a result of the lipid-specific actions, complicated membrane interaction states of PMB were observed, including adsorption on the OM surface. In contrast, for the IM or a mutative OM containing "impurity lipids" like POPE, POPG or lipid A, it could insert into the membrane via its acyl chain. Such actions of PMB influence the structure and lipid mobility of the membrane. In particular, the OM-bound PMB breaks the synchronous movement of Re LPS molecules in the outer leaflet and makes them diffuse more randomly, while its insertion into IM blocks the phospholipid diffusion and makes the membrane more homogeneous in the trajectory space. Our results provide insight into the action mechanism of PMB at a membrane level and a foundation for developing novel and safer polymyxin strategies for better clinical use.
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Affiliation(s)
- Yuliang Sun
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, Jiangsu, China
| | - Zhixiong Deng
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, Jiangsu, China
| | - Xukai Jiang
- National Glycoengineering Research Center, Shandong University, Qingdao 266237, Shandong, China
| | - Bing Yuan
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China.
| | - Kai Yang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, Jiangsu, China.
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15
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Thoma J, Burmann BM. Architects of their own environment: How membrane proteins shape the Gram-negative cell envelope. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 128:1-34. [PMID: 35034716 DOI: 10.1016/bs.apcsb.2021.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Gram-negative bacteria are surrounded by a complex multilayered cell envelope, consisting of an inner and an outer membrane, and separated by the aqueous periplasm, which contains a thin peptidoglycan cell wall. These bacteria employ an arsenal of highly specialized membrane protein machineries to ensure the correct assembly and maintenance of the membranes forming the cell envelope. Here, we review the diverse protein systems, which perform these functions in Escherichia coli, such as the folding and insertion of membrane proteins, the transport of lipoproteins and lipopolysaccharide within the cell envelope, the targeting of phospholipids, and the regulation of mistargeted envelope components. Some of these protein machineries have been known for a long time, yet still hold surprises. Others have only recently been described and some are still missing pieces or yet remain to be discovered.
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Affiliation(s)
- Johannes Thoma
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Göteborg, Sweden; Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden.
| | - Björn M Burmann
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Göteborg, Sweden; Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
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16
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González-Fernández C, Basauri A, Fallanza M, Bringas E, Oostenbrink C, Ortiz I. Fighting Against Bacterial Lipopolysaccharide-Caused Infections through Molecular Dynamics Simulations: A Review. J Chem Inf Model 2021; 61:4839-4851. [PMID: 34559524 PMCID: PMC8549069 DOI: 10.1021/acs.jcim.1c00613] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
![]()
Lipopolysaccharide
(LPS) is the primary component of the outer
leaflet of Gram-negative bacterial outer membranes. LPS elicits an
overwhelming immune response during infection, which can lead to life-threatening
sepsis or septic shock for which no suitable treatment is available
so far. As a result of the worldwide expanding multidrug-resistant
bacteria, the occurrence and frequency of sepsis are expected to increase;
thus, there is an urge to develop novel strategies for treating bacterial
infections. In this regard, gaining an in-depth understanding about
the ability of LPS to both stimulate the host immune system and interact
with several molecules is crucial for fighting against LPS-caused
infections and allowing for the rational design of novel antisepsis
drugs, vaccines and LPS sequestration and detection methods. Molecular
dynamics (MD) simulations, which are understood as being a computational
microscope, have proven to be of significant value to understand LPS-related
phenomena, driving and optimizing experimental research studies. In
this work, a comprehensive review on the methods that can be combined
with MD simulations, recently applied in LPS research, is provided.
We focus especially on both enhanced sampling methods, which enable
the exploration of more complex systems and access to larger time
scales, and free energy calculation approaches. Thereby, apart from
outlining several strategies for surmounting LPS-caused infections,
this work reports the current state-of-the-art of the methods applied
with MD simulations for moving a step forward in the development of
such strategies.
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Affiliation(s)
- Cristina González-Fernández
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005 Santander, Spain
| | - Arantza Basauri
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005 Santander, Spain
| | - Marcos Fallanza
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005 Santander, Spain
| | - Eugenio Bringas
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005 Santander, Spain
| | - Chris Oostenbrink
- Institute for Molecular Modeling and Simulation, BOKU - University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Inmaculada Ortiz
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005 Santander, Spain
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17
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Jiang X, Sun Y, Yang K, Yuan B, Velkov T, Wang L, Li J. Coarse-grained simulations uncover Gram-negative bacterial defense against polymyxins by the outer membrane. Comput Struct Biotechnol J 2021; 19:3885-3891. [PMID: 34584634 PMCID: PMC8441625 DOI: 10.1016/j.csbj.2021.06.051] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 01/12/2023] Open
Abstract
A structural model of bacterial outer membrane (OM) was developed with Ra LPS. Free energy landscape was revealed for polymyxin interactions with the OM. LPS core sugars and calcium ions confer intrinsic resistance to antibiotics.
The outer membrane (OM) of Gram-negative bacteria is a formidable barrier against antibiotics. Understanding the structure and function of the OM is essential for the discovery of novel membrane-acting agents against multidrug-resistant Gram-negative pathogens. However, it remains challenging to obtain three-dimensional structure of bacterial membranes using crystallographic approaches, which has significantly hindered the elucidation of its interaction with antibiotics. Here, we developed an asymmetric OM model consisting of rough lipopolysaccharide (LPS) and three key types of phospholipids. Using coarse-grained molecular dynamics simulations, we investigated the interaction dynamics of LPS-containing OM with the polymyxins, a last-line class of antibiotics against Gram-negative ‘superbugs’. We discovered that polymyxin molecules spontaneously penetrated the OM core sugar region where most were trapped before entering the lipid A region. Examination of the free energy profile of polymyxin penetration revealed a major free energy barrier at the LPS inner core and lipid A interface. Further analysis revealed calcium ions predominantly distributed in the inner core region and mediated extensive cross-linking interactions between LPS molecules, thereby inhibiting the penetration of polymyxins into the hydrophobic region of the OM. Collectively, our results provide novel mechanistic insights into an intrinsic defense of Gram-negative bacteria to polymyxins and may help identify new antimicrobial targets.
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Affiliation(s)
- Xukai Jiang
- National Glycoengineering Research Center, Shandong University, Qingdao, China.,Biomedicine Discovery Institute, Infection & Immunity Program, Department of Microbiology, Monash University, Melbourne, Australia
| | - Yuliang Sun
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, China
| | - Kai Yang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, China
| | - Bing Yuan
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, China
| | - Tony Velkov
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Australia
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Jian Li
- Biomedicine Discovery Institute, Infection & Immunity Program, Department of Microbiology, Monash University, Melbourne, Australia
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18
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Jiang X, Patil NA, Azad MAK, Wickremasinghe H, Yu H, Zhao J, Zhang X, Li M, Gong B, Wan L, Ma W, Thompson PE, Yang K, Yuan B, Schreiber F, Wang L, Velkov T, Roberts KD, Li J. A novel chemical biology and computational approach to expedite the discovery of new-generation polymyxins against life-threatening Acinetobacter baumannii. Chem Sci 2021; 12:12211-12220. [PMID: 34667587 PMCID: PMC8457388 DOI: 10.1039/d1sc03460j] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/12/2021] [Indexed: 01/20/2023] Open
Abstract
Multidrug-resistant Gram-negative bacteria represent a major medical challenge worldwide. New antibiotics are desperately required with 'old' polymyxins often being the only available therapeutic option. Here, we systematically investigated the structure-activity relationship (SAR) of polymyxins using a quantitative lipidomics-informed outer membrane (OM) model of Acinetobacter baumannii and a series of chemically synthesized polymyxin analogs. By integrating chemical biology and all-atom molecular dynamics simulations, we deciphered how each residue of the polymyxin molecule modulated its conformational folding and specific interactions with the bacterial OM. Importantly, a novel designed polymyxin analog FADDI-287 with predicted stronger OM penetration showed improved in vitro antibacterial activity. Collectively, our study provides a novel chemical biology and computational strategy to expedite the discovery of new-generation polymyxins against life-threatening Gram-negative 'superbugs'.
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Affiliation(s)
- Xukai Jiang
- National Glycoengineering Research Center, Shandong University Qingdao China
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
| | - Nitin A Patil
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
| | - Mohammad A K Azad
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
| | - Hasini Wickremasinghe
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
| | - Heidi Yu
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
| | - Jinxin Zhao
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
| | - Xinru Zhang
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
| | - Mengyao Li
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
| | - Bin Gong
- School of Software, Shandong University Jinan China
| | - Lin Wan
- School of Software, Shandong University Jinan China
| | - Wendong Ma
- Centre for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University Suzhou China
| | - Philip E Thompson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Science, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University Melbourne Australia
| | - Kai Yang
- Centre for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University Suzhou China
| | - Bing Yuan
- Centre for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University Suzhou China
| | - Falk Schreiber
- Department of Computer and Information Science, University of Konstanz Konstanz Germany
- Faculty of Information Technology, Monash University Melbourne Australia
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Shandong University Qingdao China
| | - Tony Velkov
- Department of Pharmacology & Therapeutics, University of Melbourne Melbourne Australia
| | - Kade D Roberts
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
| | - Jian Li
- Biomedicine Discovery Institute, Infection & Immunity Program, Monash University Melbourne Australia +61 3 9905 6450 +61 3 9903 9702
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19
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Sheikh SW, Ali A, Ahsan A, Shakoor S, Shang F, Xue T. Insights into Emergence of Antibiotic Resistance in Acid-Adapted Enterohaemorrhagic Escherichia coli. Antibiotics (Basel) 2021; 10:antibiotics10050522. [PMID: 34063307 PMCID: PMC8147483 DOI: 10.3390/antibiotics10050522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/15/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
The emergence of multidrug-resistant pathogens presents a global challenge for treating and preventing disease spread through zoonotic transmission. The water and foodborne Enterohaemorrhagic Escherichia coli (EHEC) are capable of causing intestinal and systemic diseases. The root cause of the emergence of these strains is their metabolic adaptation to environmental stressors, especially acidic pH. Acid treatment is desired to kill pathogens, but the protective mechanisms employed by EHECs cross-protect against antimicrobial peptides and thus facilitate opportunities for survival and pathogenesis. In this review, we have discussed the correlation between acid tolerance and antibiotic resistance, highlighting the identification of novel targets for potential production of antimicrobial therapeutics. We have also summarized the molecular mechanisms used by acid-adapted EHECs, such as the two-component response systems mediating structural modifications, competitive inhibition, and efflux activation that facilitate cross-protection against antimicrobial compounds. Moving beyond the descriptive studies, this review highlights low pH stress as an emerging player in the development of cross-protection against antimicrobial agents. We have also described potential gene targets for innovative therapeutic approaches to overcome the risk of multidrug-resistant diseases in healthcare and industry.
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Affiliation(s)
- Salma Waheed Sheikh
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
| | - Ahmad Ali
- School of Agronomy, Anhui Agricultural University, Hefei 230036, China;
| | - Asma Ahsan
- Faculty of Life Sciences, University of Central Punjab, Lahore 54000, Punjab, Pakistan;
| | - Sidra Shakoor
- Station de Neucfchateau, CIRAD, 97130 Sainte-Marie, Capesterre Belle Eau, Guadeloupe, France;
| | - Fei Shang
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
- Correspondence: (F.S.); (T.X.); Tel.: +86-551-657-87380 (F.S.); +86-551-657-80690 (T.X.)
| | - Ting Xue
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
- Correspondence: (F.S.); (T.X.); Tel.: +86-551-657-87380 (F.S.); +86-551-657-80690 (T.X.)
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20
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Matamoros-Recio A, Franco-Gonzalez JF, Forgione RE, Torres-Mozas A, Silipo A, Martín-Santamaría S. Understanding the Antibacterial Resistance: Computational Explorations in Bacterial Membranes. ACS OMEGA 2021; 6:6041-6054. [PMID: 33718695 PMCID: PMC7948216 DOI: 10.1021/acsomega.0c05590] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 02/09/2021] [Indexed: 05/05/2023]
Affiliation(s)
- Alejandra Matamoros-Recio
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Research Margarita Salas, CIB-CSIC, C/Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Juan Felipe Franco-Gonzalez
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Research Margarita Salas, CIB-CSIC, C/Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Rosa Ester Forgione
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Research Margarita Salas, CIB-CSIC, C/Ramiro de Maeztu, 9, 28040 Madrid, Spain
- Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant’Angelo, Università di Napoli Federico II, Via Cintia 4, 80126 Napoli, Italy
| | - Angel Torres-Mozas
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Research Margarita Salas, CIB-CSIC, C/Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Alba Silipo
- Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant’Angelo, Università di Napoli Federico II, Via Cintia 4, 80126 Napoli, Italy
| | - Sonsoles Martín-Santamaría
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Research Margarita Salas, CIB-CSIC, C/Ramiro de Maeztu, 9, 28040 Madrid, Spain
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21
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Makowski M, Felício MR, Fensterseifer ICM, Franco OL, Santos NC, Gonçalves S. EcDBS1R4, an Antimicrobial Peptide Effective against Escherichia coli with In Vitro Fusogenic Ability. Int J Mol Sci 2020; 21:ijms21239104. [PMID: 33265989 PMCID: PMC7730630 DOI: 10.3390/ijms21239104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 01/18/2023] Open
Abstract
Discovering antibiotic molecules able to hold the growing spread of antimicrobial resistance is one of the most urgent endeavors that public health must tackle. The case of Gram-negative bacterial pathogens is of special concern, as they are intrinsically resistant to many antibiotics, due to an outer membrane that constitutes an effective permeability barrier. Antimicrobial peptides (AMPs) have been pointed out as potential alternatives to conventional antibiotics, as their main mechanism of action is membrane disruption, arguably less prone to elicit resistance in pathogens. Here, we investigate the in vitro activity and selectivity of EcDBS1R4, a bioinspired AMP. To this purpose, we have used bacterial cells and model membrane systems mimicking both the inner and the outer membranes of Escherichia coli, and a variety of optical spectroscopic methodologies. EcDBS1R4 is effective against the Gram-negative E. coli, ineffective against the Gram-positive Staphylococcus aureus and noncytotoxic for human cells. EcDBS1R4 does not form stable pores in E. coli, as the peptide does not dissipate its membrane potential, suggesting an unusual mechanism of action. Interestingly, EcDBS1R4 promotes a hemi-fusion of vesicles mimicking the inner membrane of E. coli. This fusogenic ability of EcDBS1R4 requires the presence of phospholipids with a negative curvature and a negative charge. This finding suggests that EcDBS1R4 promotes a large lipid spatial reorganization able to reshape membrane curvature, with interesting biological implications herein discussed.
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Affiliation(s)
- Marcin Makowski
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; (M.M.); (M.R.F.)
| | - Mário R. Felício
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; (M.M.); (M.R.F.)
| | - Isabel C. M. Fensterseifer
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília 71966-700, Brazil; (I.C.M.F.); (O.L.F.)
- S-Inova Biotech, Pós-graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-010, Brazil
| | - Octávio L. Franco
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília 71966-700, Brazil; (I.C.M.F.); (O.L.F.)
- S-Inova Biotech, Pós-graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-010, Brazil
| | - Nuno C. Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; (M.M.); (M.R.F.)
- Correspondence: (N.C.S.); (S.G.)
| | - Sónia Gonçalves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal; (M.M.); (M.R.F.)
- Correspondence: (N.C.S.); (S.G.)
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22
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Abel S, Marchi M, Solier J, Finet S, Brillet K, Bonneté F. Structural insights into the membrane receptor ShuA in DDM micelles and in a model of gram-negative bacteria outer membrane as seen by SAXS and MD simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183504. [PMID: 33157097 DOI: 10.1016/j.bbamem.2020.183504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 09/20/2020] [Accepted: 10/20/2020] [Indexed: 11/19/2022]
Abstract
Successful crystallization of membrane proteins in detergent micelles depends on key factors such as conformational stability of the protein in micellar assemblies, the protein-detergent complex (PDC) monodispersity and favorable protein crystal contacts by suitable shielding of the protein hydrophobic surface by the detergent belt. With the aim of studying the influence of amphiphilic environment on membrane protein structure, stability and crystallizability, we combine molecular dynamics (MD) simulations with SEC-MALLS and SEC-SAXS (Size Exclusion Chromatography in line with Multi Angle Laser Light Scattering or Small Angle X-ray Scattering) experiments to describe the protein-detergent interactions that could help to rationalize PDC crystallization. In this context, we compare the protein-detergent interactions of ShuA from Shigella dysenteriae in n-Dodecyl-β-D-Maltopyranoside (DDM) with ShuA inserted in a realistic model of gram-negative bacteria outer membrane (OM) containing a mixture of bacterial lipopolysaccharide and phospholipids. To evaluate the quality of the PDC models, we compute the corresponding SAXS curves from the MD trajectories and compare with the experimental ones. We show that computed SAXS curves obtained from the MD trajectories reproduce better the SAXS obtained from the SEC-SAXS experiments for ShuA surrounded by 268 DDM molecules. The MD results show that the DDM molecules form around ShuA a closed belt whose the hydrophobic thickness appears slightly smaller (~22 Å) than the hydrophobic transmembrane domain of the protein (24.6 Å) suggested by Orientations of Proteins in Membranes (OPM) database. The simulations also show that ShuA transmembrane domain is remarkably stable in all the systems except for the extracellular and periplasmic loops that exhibit larger movements due to specific molecular interactions with lipopolysaccharides (LPS). We finally point out that this detergent behavior may lead to the occlusion of the periplasmic hydrophilic surface and poor crystal contacts leading to difficulties in crystallization of ShuA in DDM.
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Affiliation(s)
- Stéphane Abel
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
| | - Massimo Marchi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Justine Solier
- Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces, UMR 5279 CNRS Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, INP, F38000 Grenoble, France
| | - Stéphanie Finet
- Institut de Minéralogie, de Physique de Matériaux et de Cosmochimie, UMR 7590 CNRS-Sorbonne université, Bioinformatique et Biophysique, 4 Place Jussieu, F75005 Paris, France
| | - Karl Brillet
- Institut de Biologie Moléculaire et Cellulaire UPR 9002 CNRS, Architecture et Réactivité de l'ARN, 2 allée Konrad Roentgen, F67000 Strasbourg, France
| | - Françoise Bonneté
- Institut de Biologie Physico-Chimique (IBPC) UMR 7099 CNRS Université de Paris, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, 13 rue Pierre et Marie Curie, F75005 Paris, France.
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23
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Jiang X, Yang K, Han ML, Yuan B, Li J, Gong B, Velkov T, Schreiber F, Wang L, Li J. Outer Membranes of Polymyxin-Resistant Acinetobacter baumannii with Phosphoethanolamine-Modified Lipid A and Lipopolysaccharide Loss Display Different Atomic-Scale Interactions with Polymyxins. ACS Infect Dis 2020; 6:2698-2708. [PMID: 32871077 DOI: 10.1021/acsinfecdis.0c00330] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Resistance to the last-line polymyxins is increasingly reported in multidrug-resistant Gram-negative pathogens, including Acinetobacter baumannii, which develops resistance via either lipid A modification (e.g., with phosphoethanolamine [pEtN]) or even lipopolysaccharide (LPS) loss in the outer membrane (OM). Considering these two different mechanisms, quantitative membrane lipidomics data were utilized to develop three OM models representing polymyxin-susceptible and -resistant A. baumannii strains. Through all-atom molecular simulations with enhanced sampling techniques, the effect of lipid A-pEtN modification and LPS loss on the action of colistin (i.e., polymyxin E) was examined for the first time, with a focus on the dynamics and energetics of colistin penetration into these OMs. Lipid A-pEtN modification improved the OM stability, impeding the penetration of colistin into the OM; this differed from the current literature that lipid A-pEtN modification confers resistance by diminishing the initial interaction with polymyxins. In contrast, the LPS deficiency significantly reduced the negative charges on the OM surface, diminishing the binding of colistin. Moreover, both lipid A-pEtN modification and LPS loss also constituted colistin resistance through disturbing the conformational transitions of the colistin molecule. Collectively, atomic-scale interactions between polymyxins and different bacterial OMs are very different and the findings may facilitate the discovery of new-generation polymyxins against Gram-negative 'superbugs'.
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Affiliation(s)
- Xukai Jiang
- Biomedicine Discovery Institute, Infection & Immunity Program, Department of Microbiology, Monash University, Melbourne, VIC 3800, Australia
| | - Kai Yang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
| | - Mei-Ling Han
- Biomedicine Discovery Institute, Infection & Immunity Program, Department of Microbiology, Monash University, Melbourne, VIC 3800, Australia
| | - Bing Yuan
- Center for Soft Condensed Matter Physics and Interdisciplinary Research, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
| | - Jingliang Li
- Institute for Frontier Materials, Deakin University, Geelong, VIC 3217, Australia
| | - Bin Gong
- School of Software, Shandong University, Jinan 250101, China
| | - Tony Velkov
- Department of Pharmacology & Therapeutics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Falk Schreiber
- Department of Computer and Information Science, University of Konstanz, Konstanz 78467, Germany
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Jian Li
- Biomedicine Discovery Institute, Infection & Immunity Program, Department of Microbiology, Monash University, Melbourne, VIC 3800, Australia
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24
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Jiang X, Yang K, Yuan B, Gong B, Wan L, Patil NA, Swarbrick JD, Roberts KD, Schreiber F, Wang L, Velkov T, Li J. Simulations of octapeptin-outer membrane interactions reveal conformational flexibility is linked to antimicrobial potency. J Biol Chem 2020; 295:15902-15912. [PMID: 32913118 DOI: 10.1074/jbc.ra120.014856] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/09/2020] [Indexed: 12/22/2022] Open
Abstract
The octapeptins are lipopeptide antibiotics that are structurally similar to polymyxins yet retain activity against polymyxin-resistant Gram-negative pathogens, suggesting they might be used to treat recalcitrant infections. However, the basis of their unique activity is unclear because of the difficulty in generating high-resolution experimental data of the interaction of antimicrobial peptides with lipid membranes. To elucidate these structure-activity relationships, we employed all-atom molecular dynamics simulations with umbrella sampling to investigate the conformational and energetic landscape of octapeptins interacting with bacterial outer membrane (OM). Specifically, we examined the interaction of octapeptin C4 and FADDI-115, lacking a single hydroxyl group compared with octapeptin C4, with the lipid A-phosphoethanolamine modified OM of Acinetobacter baumannii Octapeptin C4 and FADDI-115 both penetrated into the OM hydrophobic center but experienced different conformational transitions from an unfolded to a folded state that was highly dependent on the structural flexibility of their respective N-terminal fatty acyl groups. The additional hydroxyl group present in the fatty acyl group of octapeptin C4 resulted in the molecule becoming trapped in a semifolded state, leading to a higher free energy barrier for OM penetration. The free energy barrier for the translocation through the OM hydrophobic layer was ∼72 kcal/mol for octapeptin C4 and 62 kcal/mol for FADDI-115. Our results help to explain the lower antimicrobial activity previously observed for octapeptin C4 compared with FADDI-115 and more broadly improve our understanding of the structure-function relationships of octapeptins. These findings may facilitate the discovery of next-generation octapeptins against polymyxin-resistant Gram-negative 'superbugs.'
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Affiliation(s)
- Xukai Jiang
- Biomedicine Discovery Institute, Infection & Immunity Program, Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Kai Yang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, China
| | - Bing Yuan
- Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou, China
| | - Bin Gong
- School of Software, Shandong University, Jinan, China
| | - Lin Wan
- School of Software, Shandong University, Jinan, China
| | - Nitin A Patil
- Biomedicine Discovery Institute, Infection & Immunity Program, Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - James D Swarbrick
- Department of Pharmacology and Therapeutics, University of Melbourne, Melbourne, Victoria, Australia
| | - Kade D Roberts
- Biomedicine Discovery Institute, Infection & Immunity Program, Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Falk Schreiber
- Department of Computer and Information Science, University of Konstanz, Konstanz, Germany
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Tony Velkov
- Department of Pharmacology and Therapeutics, University of Melbourne, Melbourne, Victoria, Australia.
| | - Jian Li
- Biomedicine Discovery Institute, Infection & Immunity Program, Department of Microbiology, Monash University, Melbourne, Victoria, Australia.
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25
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Mechanism of polyamine induced colistin resistance through electrostatic networks on bacterial outer membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183297. [PMID: 32339485 DOI: 10.1016/j.bbamem.2020.183297] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/21/2020] [Accepted: 03/29/2020] [Indexed: 12/18/2022]
Abstract
Naturally occurring linear polyamines are known to enable bacteria to be resistant to cationic membrane active peptides. To understand this protective mechanism, molecular dynamics simulations are employed to probe their effect on a model bacterial outer membrane. Being protonated at physiological pH, the amine groups of the polyamine engage in favorable electrostatic interactions with the negatively charged phosphate groups of the membrane. Additionally, the amine groups form large number of hydrogen bonds with the phosphate groups. At high concentrations, these hydrogen bonds and the electrostatic network can non-covalently crosslink the lipid A molecules, resulting in stabilization of the outer membrane against membrane active antibiotics such as colistin and polymyxin B. Moreover, large polyamine molecules (e.g., spermidine) have a stronger stabilization effect than small polyamine molecules (e.g., ethylene diamine). The atomistic insights provide useful guidance for the design of next generation membrane active amine-rich antibiotics, especially to tackle the growing threat of multi-drug resistance of Gram negative bacteria.
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26
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Sharma P, Parthasarathi S, Patil N, Waskar M, Raut JS, Puranik M, Ayappa KG, Basu JK. Assessing Barriers for Antimicrobial Penetration in Complex Asymmetric Bacterial Membranes: A Case Study with Thymol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8800-8814. [PMID: 32609530 DOI: 10.1021/acs.langmuir.0c01124] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The bacterial cell envelope is a complex multilayered structure evolved to protect bacteria in hostile environments. An understanding of the molecular basis for the interaction and transport of antibacterial therapeutics with the bacterial cell envelope will enable the development of drug molecules to combat bacterial infections and suppress the emergence of drug-resistant strains. Here we report the successful creation of an in vitro supported lipid bilayer (SLB) platform of the outer membrane (OM) of E. coli, an archetypical Gram-negative bacterium, containing the full smooth lipopolysaccharide (S-LPS) architecture of the membrane. Using this platform, we performed fluorescence correlation spectroscopy (FCS) in combination with molecular dynamics (MD) simulations to measure lipid diffusivities and provide molecular insights into the transport of natural antimicrobial agent thymol. Lipid diffusivities measured on symmetric supported lipid bilayers made up of inner membrane lipids show a distinct increase in the presence of thymol as also corroborated by MD simulations. However, lipid diffusivities in the asymmetric OM consisting of only S-LPS are invariant upon exposure to thymol. Increasing the phospholipid content in the LPS-containing outer leaflet improved the penetration toward thymol as reflected in slightly higher relative diffusivity changes in the inner leaflet when compared with the outer leaflet. Free-energy computations reveal the presence of a barrier (∼6 kT) only in the core-saccharide region of the OM for the translocation of thymol while the external O-antigen part is easily traversed. In contrast, thymol spontaneously inserts into the inner membrane. In addition to providing leaflet-resolved penetration barriers in bacterial membranes, we also assess the ability of small molecules to penetrate various membrane components. With rising bacterial resistance, our study opens up the possibility of screening potential antimicrobial drug candidates using these realistic model platforms for Gram-negative bacteria.
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Affiliation(s)
| | | | - Nivedita Patil
- Unilever RD Bangalore, 64 Main Road, Whitefield, Bangalore 560066, India
| | - Morris Waskar
- Unilever RD Bangalore, 64 Main Road, Whitefield, Bangalore 560066, India
| | - Janhavi S Raut
- Unilever RD Bangalore, 64 Main Road, Whitefield, Bangalore 560066, India
| | - Mrinalini Puranik
- Unilever RD Bangalore, 64 Main Road, Whitefield, Bangalore 560066, India
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27
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Martinotti C, Ruiz-Perez L, Deplazes E, Mancera RL. Molecular Dynamics Simulation of Small Molecules Interacting with Biological Membranes. Chemphyschem 2020; 21:1486-1514. [PMID: 32452115 DOI: 10.1002/cphc.202000219] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/22/2020] [Indexed: 12/12/2022]
Abstract
Cell membranes protect and compartmentalise cells and their organelles. The semi-permeable nature of these membranes controls the exchange of solutes across their structure. Characterising the interaction of small molecules with biological membranes is critical to understanding of physiological processes, drug action and permeation, and many biotechnological applications. This review provides an overview of how molecular simulations are used to study the interaction of small molecules with biological membranes, with a particular focus on the interactions of water, organic compounds, drugs and short peptides with models of plasma cell membrane and stratum corneum lipid bilayers. This review will not delve on other types of membranes which might have different composition and arrangement, such as thylakoid or mitochondrial membranes. The application of unbiased molecular dynamics simulations and enhanced sampling methods such as umbrella sampling, metadynamics and replica exchange are described using key examples. This review demonstrates how state-of-the-art molecular simulations have been used successfully to describe the mechanism of binding and permeation of small molecules with biological membranes, as well as associated changes to the structure and dynamics of these membranes. The review concludes with an outlook on future directions in this field.
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Affiliation(s)
- Carlo Martinotti
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and, Curtin Institute for Computation, Curtin University, Perth, WA 6845, Australia
| | - Lanie Ruiz-Perez
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and, Curtin Institute for Computation, Curtin University, Perth, WA 6845, Australia
| | - Evelyne Deplazes
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Ricardo L Mancera
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and, Curtin Institute for Computation, Curtin University, Perth, WA 6845, Australia
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28
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Molecular characterization of the outer membrane of Pseudomonas aeruginosa. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183151. [DOI: 10.1016/j.bbamem.2019.183151] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 10/28/2019] [Accepted: 12/06/2019] [Indexed: 01/07/2023]
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29
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Rice A, Rooney MT, Greenwood AI, Cotten ML, Wereszczynski J. Lipopolysaccharide Simulations Are Sensitive to Phosphate Charge and Ion Parameterization. J Chem Theory Comput 2020; 16:1806-1815. [PMID: 32023054 DOI: 10.1021/acs.jctc.9b00868] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The high proportion of lipopolysaccharide (LPS) molecules in the outer membrane of Gram-negative bacteria makes it a highly effective barrier to small molecules, antibiotic drugs, and other antimicrobial agents. Given this vital role in protecting bacteria from potentially hostile environments, simulations of LPS bilayers and outer membrane systems represent a critical tool for understanding the mechanisms of bacterial resistance and the development of new antibiotic compounds that circumvent these defenses. The basis of these simulations is parameterizations of LPS, which have been developed for all major molecular dynamics force fields. However, these parameterizations differ in both the protonation state of LPS and how LPS membranes behave in the presence of various ion species. To address these discrepancies and understand the effects of phosphate charge on bilayer properties, simulations were performed for multiple distinct LPS chemotypes with different ion parameterizations in both protonated or deprotonated lipid A states. These simulations show that bilayer properties, such as the area per lipid and inter-lipid hydrogen bonding, are highly influenced by the choice of phosphate group charges, cation type, and ion parameterization, with protonated LPS and monovalent cations with modified nonbonded parameters providing the best match to the experiments. Additionally, alchemical free energy simulations were performed to determine theoretical pKa values for LPS and subsequently validated by 31P solid-state nuclear magnetic resonance experiments. Results from these complementary computational and experimental studies demonstrate that the protonated state dominates at physiological pH, contrary to the deprotonated form modeled by many LPS force fields. Overall, these results highlight the sensitivity of LPS simulations to phosphate charge and ion parameters while offering recommendations for how existing models should be updated for consistency between force fields as well as to best match experiments.
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Affiliation(s)
- Amy Rice
- Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Mary T Rooney
- Department of Applied Science, College of William and Mary, Williamsburg, Virginia 23185, United States
| | - Alexander I Greenwood
- Department of Applied Science, College of William and Mary, Williamsburg, Virginia 23185, United States.,Department of Physics, College of William and Mary, Williamsburg, Virginia 23185, United States
| | - Myriam L Cotten
- Department of Applied Science, College of William and Mary, Williamsburg, Virginia 23185, United States
| | - Jeff Wereszczynski
- Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, Illinois 60616, United States
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30
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Martynowycz MW, Rice A, Andreev K, Nobre TM, Kuzmenko I, Wereszczynski J, Gidalevitz D. Salmonella Membrane Structural Remodeling Increases Resistance to Antimicrobial Peptide LL-37. ACS Infect Dis 2019; 5:1214-1222. [PMID: 31083918 DOI: 10.1021/acsinfecdis.9b00066] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Gram-negative bacteria are protected from their environment by an outer membrane that is primarily composed of lipopolysaccharides (LPSs). Under stress, pathogenic serotypes of Salmonella enterica remodel their LPSs through the PhoPQ two-component regulatory system that increases resistance to both conventional antibiotics and antimicrobial peptides (AMPs). Acquired resistance to AMPs is contrary to the established narrative that AMPs circumvent bacterial resistance by targeting the general chemical properties of membrane lipids. However, the specific mechanisms underlying AMP resistance remain elusive. Here we report a 2-fold increase in bacteriostatic concentrations of human AMP LL-37 for S. enterica with modified LPSs. LPSs with and without chemical modifications were isolated and investigated by Langmuir films coupled with grazing-incidence X-ray diffraction (GIXD) and specular X-ray reflectivity (XR). The initial interactions between LL-37 and LPS bilayers were probed using all-atom molecular dynamics simulations. These simulations suggest that initial association is nonspecific to the type of LPS and governed by hydrogen bonding to the LPS outer carbohydrates. GIXD experiments indicate that the interactions of the peptide with monolayers reduce the number of crystalline domains but greatly increase the typical domain size in both LPS isoforms. Electron densities derived from XR experiments corroborate the bacteriostatic values found in vitro and indicate that peptide intercalation is reduced by LPS modification. We hypothesize that defects at the liquid-ordered boundary facilitate LL-37 intercalation into the outer membrane, whereas PhoPQ-mediated LPS modification protects against this process by having innately increased crystallinity. Since induced ordering has been observed with other AMPs and drugs, LPS modification may represent a general mechanism by which Gram-negative bacteria protect against host innate immunity.
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Affiliation(s)
- Michael W. Martynowycz
- Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, 10 West 35th Street, Chicago, Illinois 60616, United States
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Building 401, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Amy Rice
- Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, 10 West 35th Street, Chicago, Illinois 60616, United States
| | - Konstantin Andreev
- Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, 10 West 35th Street, Chicago, Illinois 60616, United States
| | - Thatyane M. Nobre
- Departamento de Fisica e Ciecias dos Materiais, Instituto de Fisica de São Carlos, 400 Parque Arnold Schimidt, 13566-590 São Carlos-SP, Brazil
| | - Ivan Kuzmenko
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Building 401, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Jeff Wereszczynski
- Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, 10 West 35th Street, Chicago, Illinois 60616, United States
| | - David Gidalevitz
- Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, 10 West 35th Street, Chicago, Illinois 60616, United States
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31
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Marrink SJ, Corradi V, Souza PC, Ingólfsson HI, Tieleman DP, Sansom MS. Computational Modeling of Realistic Cell Membranes. Chem Rev 2019; 119:6184-6226. [PMID: 30623647 PMCID: PMC6509646 DOI: 10.1021/acs.chemrev.8b00460] [Citation(s) in RCA: 410] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Indexed: 12/15/2022]
Abstract
Cell membranes contain a large variety of lipid types and are crowded with proteins, endowing them with the plasticity needed to fulfill their key roles in cell functioning. The compositional complexity of cellular membranes gives rise to a heterogeneous lateral organization, which is still poorly understood. Computational models, in particular molecular dynamics simulations and related techniques, have provided important insight into the organizational principles of cell membranes over the past decades. Now, we are witnessing a transition from simulations of simpler membrane models to multicomponent systems, culminating in realistic models of an increasing variety of cell types and organelles. Here, we review the state of the art in the field of realistic membrane simulations and discuss the current limitations and challenges ahead.
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Affiliation(s)
- Siewert J. Marrink
- Groningen
Biomolecular Sciences and Biotechnology Institute & Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Valentina Corradi
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Paulo C.T. Souza
- Groningen
Biomolecular Sciences and Biotechnology Institute & Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Helgi I. Ingólfsson
- Biosciences
and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| | - D. Peter Tieleman
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Mark S.P. Sansom
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K.
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32
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Li Y, Niu D, Bai Y, Lan T, Peng M, Dong Z, Li J. Identification of a novel C1q complement component in razor clam Sinonovacula constricta and its role in antibacterial activity. FISH & SHELLFISH IMMUNOLOGY 2019; 87:193-201. [PMID: 30639866 DOI: 10.1016/j.fsi.2019.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 01/07/2019] [Accepted: 01/10/2019] [Indexed: 06/09/2023]
Abstract
The serum complement component C1q mediates a variety of immune regulatory functions. Herein, we identified a globular head C1q (ghC1q) gene in razor clam Sinonovacula constricta. The complete Sc-ghC1q gene was 872 bp long included an 81 bp 5'-untranslated region (UTR), a 95 bp 3'-UTR with a poly(A) tail, and an open reading frame (ORF) of 696 bp. The mRNA expression of Sc-ghC1q was upregulated in hepatopancreas and hemocytes. After Staphylococcus aureus or Vibrio anguillarum challenge, Sc-ghC1q mRNA transcript abundance was significantly upregulated in hemolymph. Recombinant Sc-ghC1q protein could bind lipopolysaccharide (LPS) and lipoteichoic acid (LTA), and it could agglutinate both Gram-positive and Gram-negative bacteria. Additionally, flow cytometry revealed that Sc-ghC1q strongly promoted phagocytosis in hemocytes. Together, these results demonstrated that Sc-ghC1q played an important role in innate immunity in S. constricta.
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Affiliation(s)
- Yan Li
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Donghong Niu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; National Demonstration Centre for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China.
| | - Yuqi Bai
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Tianyi Lan
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Maoxiao Peng
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Zhiguo Dong
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Huaihai Institute of Technology, Lianyungang, 222005, China
| | - Jiale Li
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; Shanghai Engineering Research Centre of Aquaculture, Shanghai, 201306, China.
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33
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Traini G, Ruiz-de-Angulo A, Blanco-Canosa JB, Zamacola Bascarán K, Molinaro A, Silipo A, Escors D, Mareque-Rivas JC. Cancer Immunotherapy of TLR4 Agonist-Antigen Constructs Enhanced with Pathogen-Mimicking Magnetite Nanoparticles and Checkpoint Blockade of PD-L1. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1803993. [PMID: 30569516 DOI: 10.1002/smll.201803993] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 11/07/2018] [Indexed: 05/10/2023]
Abstract
Despite the tremendous potential of Toll-like receptor 4 (TLR4) agonists in vaccines, their efficacy as monotherapy to treat cancer has been limited. Only some lipopolysaccharides (LPS) isolated from particular bacterial strains or structures like monophosphoryl lipid A (MPLA) derived from lipooligosaccharide (LOS), avoid toxic overactivation of innate immune responses while retaining adequate immunogenicity to act as adjuvants. Here, different LOS structures are incorporated into nanoparticle-filled phospholipid micelles for efficient vaccine delivery and more potent cancer immunotherapy. The structurally unique LOS of the plant pathogen Xcc is incorporated into phospholipid micelles encapsulating iron oxide nanoparticles, producing stable pathogen-mimicking nanostructures suitable for targeting antigen presenting cells in the lymph nodes. The antigen is conjugated via a hydrazone bond, enabling rapid, easy-to-monitor and high-yield antigen ligation at low concentrations. The protective effect of these constructs is investigated against a highly aggressive model for tumor immunotherapy. The results show that the nanovaccines lead to a higher-level antigen-specific cytotoxic T lymphocyte (CTL) effector and memory responses, which when combined with abrogation of the immunosuppressive programmed death-ligand 1 (PD-L1), provide 100% long-term protection against repeated tumor challenge. This nanovaccine platform in combination with checkpoint inhibition of PD-L1 represents a promising approach to improve the cancer immunotherapy of TLR4 agonists.
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Affiliation(s)
- Giordano Traini
- CIC biomaGUNE, Paseo Miramón 182, 20014, San Sebastián, Spain
| | | | | | | | - Antonio Molinaro
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant' Angelo, Via Cintia 4, 80126, Napoli, Italy
| | - Alba Silipo
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant' Angelo, Via Cintia 4, 80126, Napoli, Italy
| | - David Escors
- Navarrabiomed-Biomedical Research Centre, Fundación Miguel Servet-IdISNA, Complejo Hospitalario de Navarra, 31008, Pamplona, Spain
| | - Juan C Mareque-Rivas
- Department of Chemistry and Centre for NanoHealth, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
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