1
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Morris SM, Wiens L, Rose O, Fritz G, Rogers T, Gebhard S. Regulatory interactions between daptomycin- and bacitracin-responsive pathways coordinate the cell envelope antibiotic resistance response of Enterococcus faecalis. Mol Microbiol 2024; 121:1148-1163. [PMID: 38646792 DOI: 10.1111/mmi.15264] [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: 11/17/2022] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 04/23/2024]
Abstract
Enterococcal infections frequently show high levels of antibiotic resistance, including to cell envelope-acting antibiotics like daptomycin (DAP). While we have a good understanding of the resistance mechanisms, less is known about the control of such resistance genes in enterococci. Previous work unveiled a bacitracin resistance network, comprised of the sensory ABC transporter SapAB, the two-component system (TCS) SapRS and the resistance ABC transporter RapAB. Interestingly, components of this system have recently been implicated in DAP resistance, a role usually regulated by the TCS LiaFSR. To better understand the regulation of DAP resistance and how this relates to mutations observed in DAP-resistant clinical isolates of enterococci, we here explored the interplay between these two regulatory pathways. Our results show that SapR regulates an additional resistance operon, dltXABCD, a known DAP resistance determinant, and show that LiaFSR regulates the expression of sapRS. This regulatory structure places SapRS-target genes under dual control, where expression is directly controlled by SapRS, which itself is up-regulated through LiaFSR. The network structure described here shows how Enterococcus faecalis coordinates its response to cell envelope attack and can explain why clinical DAP resistance often emerges via mutations in regulatory components.
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Affiliation(s)
- Sali M Morris
- Life Sciences Department, Milner Centre for Evolution, University of Bath, Bath, UK
| | - Laura Wiens
- Institute of Molecular Physiology, Johannes-Gutenberg-University Mainz, Mainz, Germany
| | - Olivia Rose
- Life Sciences Department, Milner Centre for Evolution, University of Bath, Bath, UK
| | - Georg Fritz
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Tim Rogers
- Department of Mathematical Sciences, University of Bath, Bath, UK
| | - Susanne Gebhard
- Life Sciences Department, Milner Centre for Evolution, University of Bath, Bath, UK
- Institute of Molecular Physiology, Johannes-Gutenberg-University Mainz, Mainz, Germany
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2
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Sass P. Antibiotics: Precious Goods in Changing Times. Methods Mol Biol 2023; 2601:3-26. [PMID: 36445576 DOI: 10.1007/978-1-0716-2855-3_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Antibiotics represent a first line of defense of diverse microorganisms, which produce and use antibiotics to counteract natural enemies or competitors for nutritional resources in their nearby environment. For antimicrobial activity, nature has invented a great variety of antibiotic modes of action that involve the perturbation of essential bacterial structures or biosynthesis pathways of macromolecules such as the bacterial cell wall, DNA, RNA, or proteins, thereby threatening the specific microbial lifestyle and eventually even survival. However, along with highly inventive modes of antibiotic action, nature also developed a comparable set of resistance mechanisms that help the bacteria to circumvent antibiotic action. Microorganisms have evolved specific adaptive responses that allow to appropriately react to the presence of antimicrobial agents, thereby ensuring survival during antimicrobial stress. In times of rapid development and spread of antibiotic (multi-)resistance, new resistance-breaking strategies to counteract bacterial infections are desperately needed. This chapter is an update to Chapter 1 of the first edition of this book and intends to give an overview of common antibiotics and their target pathways. It will also present examples for new antibiotics with novel modes of action, illustrating that nature's repertoire of innovative new antimicrobial agents has not been fully exploited yet, and we still might find new drugs that help to evade established antimicrobial resistance strategies.
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Affiliation(s)
- Peter Sass
- Interfaculty Institute for Microbiology and Infection Medicine, Microbial Bioactive Compounds, University of Tübingen, Tübingen, Germany.
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3
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Sulaiman JE, Long L, Qian PY, Lam H. Proteome profiling of evolved methicillin-resistant Staphylococcus aureus strains with distinct daptomycin tolerance and resistance phenotypes. Front Microbiol 2022; 13:970146. [PMID: 35992709 PMCID: PMC9386379 DOI: 10.3389/fmicb.2022.970146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 07/13/2022] [Indexed: 12/04/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a highly dangerous pathogen, and daptomycin has been increasingly used to treat its infections in clinics. Recently, several groups have shown that tolerance and resistance of microbes can evolve rapidly under cyclic antibiotic exposure. We have previously shown that the same tolerance and resistance development occurs in MRSA treated with daptomycin in an adaptive laboratory evolution (ALE) experiment. In the present study, we performed proteomic analysis to compare six daptomycin-tolerant and resistant MRSA strains that were evolved from the same ancestral strain. The strain with a higher tolerance level than the others had the most different proteome and response to antibiotic treatment, resembling those observed in persister cells, which are small subpopulations of bacteria that survive lethal antibiotics treatment. By comparing the proteome changes across strains with similar phenotypes, we identified the key proteins that play important roles in daptomycin tolerance and resistance in MRSA. We selected two candidates to be confirmed by gene overexpression analysis. Overexpression of EcsA1 and FabG, which were up-regulated in all of the tolerant evolved strains, led to increased daptomycin tolerance in wild-type MRSA. The proteomics data also suggested that cell wall modulations were implicated in both resistance and tolerance, but in different ways. While the resistant strains had peptidoglycan changes and a more positive surface charge to directly repel daptomycin, the tolerant strains possessed different cell wall changes that do not involve the peptidoglycan nor alterations of the surface charge. Overall, our study showed the differential proteome profiles among multiple tolerant and resistant strains, pinpointed the key proteins for the two phenotypes and revealed the differences in cell wall modulations between the daptomycin-tolerant/resistant strains.
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Affiliation(s)
- Jordy Evan Sulaiman
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Lexin Long
- Department of Ocean Science and Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Pei-Yuan Qian
- Department of Ocean Science and Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Henry Lam
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- *Correspondence: Henry Lam,
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4
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Wang Z, Koirala B, Hernandez Y, Zimmerman M, Brady SF. Bioinformatic prospecting and synthesis of a bifunctional lipopeptide antibiotic that evades resistance. Science 2022; 376:991-996. [PMID: 35617397 PMCID: PMC10904332 DOI: 10.1126/science.abn4213] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Emerging resistance to currently used antibiotics is a global public health crisis. Because most of the biosynthetic capacity within the bacterial kingdom has remained silent in previous antibiotic discovery efforts, uncharacterized biosynthetic gene clusters found in bacterial genome-sequencing studies remain an appealing source of antibiotics with distinctive modes of action. Here, we report the discovery of a naturally inspired lipopeptide antibiotic called cilagicin, which we chemically synthesized on the basis of a detailed bioinformatic analysis of the cil biosynthetic gene cluster. Cilagicin's ability to sequester two distinct, indispensable undecaprenyl phosphates used in cell wall biosynthesis, together with the absence of detectable resistance in laboratory tests and among multidrug-resistant clinical isolates, makes it an appealing candidate for combating antibiotic-resistant pathogens.
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Affiliation(s)
- Zongqiang Wang
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, New York, NY 10065, USA
| | - Bimal Koirala
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, New York, NY 10065, USA
| | - Yozen Hernandez
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, New York, NY 10065, USA
| | - Matthew Zimmerman
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA
| | - Sean F Brady
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, New York, NY 10065, USA
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5
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Shinjyo Y, Midorikawa N, Matsumoto T, Sugaya Y, Ozawa Y, Oana A, Horie C, Yoshikawa H, Takahashi Y, Hasegawa T, Asai K. Analysis of cell death in Bacillus subtilis caused by sesquiterpenes from Chrysopogon zizanioides (L.) Roberty. J GEN APPL MICROBIOL 2022; 68:62-70. [PMID: 35418537 DOI: 10.2323/jgam.2021.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Recently, the antibacterial effects of essential oils have been investigated in addition to their therapeutic purposes. Owing to their hydrophobic nature, they are thought to perturb the integrity of the bacterial cell membrane, leading to cell death. Against such antibiotic challenges, bacteria develop mechanisms for cell envelope stress responses (CESR). In Bacillus subtilis, a gram-positive sporulating soil bacterium, the extracytoplasmic function (ECF) sigma factor-mediated response system plays a pivotal role in CESR. Among them, σM is strongly involved in response to cell envelope stress, including a shortage of available bactoprenol. Vetiver essential oil, a product of Chrysopogon zizanioides (L.) Roberty root, is also known to possess bactericidal activity. σM was exclusively and strongly induced when the cells were exposed to Vetiver extract, and depletion of multi-ECF sigma factors (ΔsigM, ΔsigW, ΔsigX, and ΔsigV) enhanced sensitivity to it. From this quadruple mutant strain, the suppressor strains, which restored resistance to the bactericidal activity of Vetiver extract, emerged, although attempts to obtain resistant strains from the wild type did not succeed. Whole-genome resequencing of the suppressor strains and genetic analysis revealed inactivation of xseB or pnpA, which code for exodeoxyribonuclease or polynucleotide phosphorylase, respectively. This allowed the quadruple mutant strain to escape from cell death caused by Vetiver extract. Composition analysis suggested that the sesquiterpene, khusimol, might contribute to the bactericidal activity of the Vetiver extract.
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Affiliation(s)
- Yu Shinjyo
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Naoya Midorikawa
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University
| | - Takashi Matsumoto
- Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture
| | - Yuki Sugaya
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Yoshiki Ozawa
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Ayumi Oana
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Chiaki Horie
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Hirofumi Yoshikawa
- Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture.,Department of Bioscience, Tokyo University of Agriculture
| | - Yasuhiro Takahashi
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University
| | - Toshio Hasegawa
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University
| | - Kei Asai
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University.,Department of Bioscience, Tokyo University of Agriculture
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6
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Surfactin Shows Relatively Low Antimicrobial Activity against Bacillus subtilis and Other Bacterial Model Organisms in the Absence of Synergistic Metabolites. Microorganisms 2022; 10:microorganisms10040779. [PMID: 35456828 PMCID: PMC9030240 DOI: 10.3390/microorganisms10040779] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/30/2022] [Accepted: 04/02/2022] [Indexed: 11/17/2022] Open
Abstract
Surfactin is described as a powerful biosurfactant and is natively produced by Bacillus subtilis in notable quantities. Among other industrially relevant characteristics, antimicrobial properties have been attributed to surfactin-producing Bacillus isolates. To investigate this property, stress approaches were carried out with biotechnologically established strains of Corynebacterium glutamicum, Bacillus subtilis, Escherichia coli and Pseudomonas putida with the highest possible amounts of surfactin. Contrary to the popular opinion, the highest growth-reducing effects were detectable in B. subtilis and E. coli after surfactin treatment of 100 g/L with 35 and 33%, respectively, while P. putida showed no growth-specific response. In contrast, other antimicrobial biosurfactants, like rhamnolipids and sophorolipids, showed significantly stronger effects on bacterial growth. Since the addition of high amounts of surfactin in defined mineral salt medium reduced the cell growth of B. subtilis by about 40%, the initial stress response at the protein level was analyzed by mass spectrometry, showing induction of stress proteins under control of alternative sigma factors σB and σW as well as the activation of LiaRS two-component system. Overall, although surfactin is associated with antimicrobial properties, relatively low growth-reducing effects could be demonstrated after the surfactin addition, challenging the general claim of the antimicrobial properties of surfactin.
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7
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Popp PF, Friebel L, Benjdia A, Guillot A, Berteau O, Mascher T. The Epipeptide Biosynthesis Locus epeXEPAB Is Widely Distributed in Firmicutes and Triggers Intrinsic Cell Envelope Stress. Microb Physiol 2021; 31:306-318. [PMID: 34120110 DOI: 10.1159/000516750] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/22/2021] [Indexed: 11/19/2022]
Abstract
The epeXEPAB (formerly yydFGHIJ) locus of Bacillus subtilis encodes a minimalistic biosynthetic pathway for a linear antimicrobial epipeptide, EpeX, which is ribosomally produced and post-translationally processed by the action of the radical-SAM epimerase, EpeE, and a membrane-anchored signal 2 peptide peptidase, EpeP. The ABC transporter EpeAB provides intrinsic immunity against self-produced EpeX, without conferring resistance against extrinsically added EpeX. EpeX specifically targets, and severely perturbs the integrity of the cytoplasmic membrane, which leads to the induction of the Lia-dependent envelope stress response. Here, we provide new insights into the distribution, expression, and regulation of the minimalistic epeXEPAB locus of B. subtilis, as well as the biosynthesis and biological efficiency of the produced epipeptide EpeX*. A comprehensive comparative genomics study demonstrates that the epe-locus is restricted to but widely distributed within the phylum Firmicutes. The gene products of epeXEP are necessary and sufficient for the production of the mature antimicrobial peptide EpeX*. In B. subtilis, the epeXEPAB locus is transcribed from three different promoters, one upstream of epeX (PepeX) and two within epeP (PepeA1 and PepeA2). While the latter two are mostly constitutive, PepeX shows a growth phase-dependent induction at the onset of stationary phase. We demonstrate that this regulation is the result of the antagonistic action of two global regulators: The transition state regulator AbrB keeps the epe locus shut off during exponential growth by direct binding. This tight repression is relieved by the master regulator of sporulation, Spo0A, which counteracts the AbrB-dependent repression of epeXEPAB expression during the transition to stationary phase. The net result of these three -promoters is an expression pattern that ensures EpeAB-dependent autoimmunity prior to EpeX* production. In the absence of EpeAB, the general envelope stress response proteins LiaIH can compensate for the loss of specific autoimmunity by providing sufficient protection against the membrane-perturbating action of EpeX*. Hence, the transcriptional regulation of epe expression and the resulting intrinsic induction of the two corresponding resistance functions, encoded by epeAB and liaIH, are well balanced to provide a need-based immunity against mature EpeX*.
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Affiliation(s)
- Philipp F Popp
- Institute of Microbiology, Technische Universität (TU) Dresden, Dresden, Germany.,Institute for Biology - Bacterial Physiology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Lena Friebel
- Institute of Microbiology, Technische Universität (TU) Dresden, Dresden, Germany
| | - Alhosna Benjdia
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, Jouy-en-Josas, France
| | - Alain Guillot
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, Jouy-en-Josas, France
| | - Olivier Berteau
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, Jouy-en-Josas, France
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität (TU) Dresden, Dresden, Germany
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8
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Dijksteel GS, Ulrich MMW, Middelkoop E, Boekema BKHL. Review: Lessons Learned From Clinical Trials Using Antimicrobial Peptides (AMPs). Front Microbiol 2021; 12:616979. [PMID: 33692766 PMCID: PMC7937881 DOI: 10.3389/fmicb.2021.616979] [Citation(s) in RCA: 183] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 01/29/2021] [Indexed: 12/15/2022] Open
Abstract
Antimicrobial peptides (AMPs) or host defense peptides protect the host against various pathogens such as yeast, fungi, viruses and bacteria. AMPs also display immunomodulatory properties ranging from the modulation of inflammatory responses to the promotion of wound healing. More interestingly, AMPs cause cell disruption through non-specific interactions with the membrane surface of pathogens. This is most likely responsible for the low or limited emergence of bacterial resistance against many AMPs. Despite the increasing number of antibiotic-resistant bacteria and the potency of novel AMPs to combat such pathogens, only a few AMPs are in clinical use. Therefore, the current review describes (i) the potential of AMPs as alternatives to antibiotics, (ii) the challenges toward clinical implementation of AMPs and (iii) strategies to improve the success rate of AMPs in clinical trials, emphasizing the lessons we could learn from these trials.
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Affiliation(s)
- Gabrielle S Dijksteel
- Association of Dutch Burn Centres, Beverwijk, Netherlands.,Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Magda M W Ulrich
- Association of Dutch Burn Centres, Beverwijk, Netherlands.,Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Department of Pathology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Esther Middelkoop
- Association of Dutch Burn Centres, Beverwijk, Netherlands.,Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
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9
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The Cell Envelope Stress Response of Bacillus subtilis towards Laspartomycin C. Antibiotics (Basel) 2020; 9:antibiotics9110729. [PMID: 33114184 PMCID: PMC7690785 DOI: 10.3390/antibiotics9110729] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 11/17/2022] Open
Abstract
Cell wall antibiotics are important tools in our fight against Gram-positive pathogens, but many strains become increasingly resistant against existing drugs. Laspartomycin C is a novel antibiotic that targets undecaprenyl phosphate (UP), a key intermediate in the lipid II cycle of cell wall biosynthesis. While laspartomycin C has been thoroughly examined biochemically, detailed knowledge about potential resistance mechanisms in bacteria is lacking. Here, we use reporter strains to monitor the activity of central resistance modules in the Bacillus subtilis cell envelope stress response network during laspartomycin C attack and determine the impact on the resistance of these modules using knock-out strains. In contrast to the closely related UP-binding antibiotic friulimicin B, which only activates ECF σ factor-controlled stress response modules, we find that laspartomycin C additionally triggers activation of stress response systems reacting to membrane perturbation and blockage of other lipid II cycle intermediates. Interestingly, none of the studied resistance genes conferred any kind of protection against laspartomycin C. While this appears promising for therapeutic use of laspartomycin C, it raises concerns that existing cell envelope stress response networks may already be poised for spontaneous development of resistance during prolonged or repeated exposure to this new antibiotic.
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10
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Schäfer AB, Wenzel M. A How-To Guide for Mode of Action Analysis of Antimicrobial Peptides. Front Cell Infect Microbiol 2020; 10:540898. [PMID: 33194788 PMCID: PMC7604286 DOI: 10.3389/fcimb.2020.540898] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a promising alternative to classical antibiotics in the fight against multi-resistant bacteria. They are produced by organisms from all domains of life and constitute a nearly universal defense mechanism against infectious agents. No drug can be approved without information about its mechanism of action. In order to use them in a clinical setting, it is pivotal to understand how AMPs work. While many pore-forming AMPs are well-characterized in model membrane systems, non-pore-forming peptides are often poorly understood. Moreover, there is evidence that pore formation may not happen or not play a role in vivo. It is therefore imperative to study how AMPs interact with their targets in vivo and consequently kill microorganisms. This has been difficult in the past, since established methods did not provide much mechanistic detail. Especially, methods to study membrane-active compounds have been scarce. Recent advances, in particular in microscopy technology and cell biological labeling techniques, now allow studying mechanisms of AMPs in unprecedented detail. This review gives an overview of available in vivo methods to investigate the antibacterial mechanisms of AMPs. In addition to classical mode of action classification assays, we discuss global profiling techniques, such as genomic and proteomic approaches, as well as bacterial cytological profiling and other cell biological assays. We cover approaches to determine the effects of AMPs on cell morphology, outer membrane, cell wall, and inner membrane properties, cellular macromolecules, and protein targets. We particularly expand on methods to examine cytoplasmic membrane parameters, such as composition, thickness, organization, fluidity, potential, and the functionality of membrane-associated processes. This review aims to provide a guide for researchers, who seek a broad overview of the available methodology to study the mechanisms of AMPs in living bacteria.
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Affiliation(s)
| | - Michaela Wenzel
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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11
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Karas JA, Carter GP, Howden BP, Turner AM, Paulin OKA, Swarbrick JD, Baker MA, Li J, Velkov T. Structure–Activity Relationships of Daptomycin Lipopeptides. J Med Chem 2020; 63:13266-13290. [DOI: 10.1021/acs.jmedchem.0c00780] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- John A. Karas
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Glen P. Carter
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Benjamin P. Howden
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Adrianna M. Turner
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Olivia K. A. Paulin
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - James D. Swarbrick
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Mark. A. Baker
- Priority Research Centre in Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Jian Li
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Tony Velkov
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
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12
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Khodadadi E, Zeinalzadeh E, Taghizadeh S, Mehramouz B, Kamounah FS, Khodadadi E, Ganbarov K, Yousefi B, Bastami M, Kafil HS. Proteomic Applications in Antimicrobial Resistance and Clinical Microbiology Studies. Infect Drug Resist 2020; 13:1785-1806. [PMID: 32606829 PMCID: PMC7305820 DOI: 10.2147/idr.s238446] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 05/23/2020] [Indexed: 12/11/2022] Open
Abstract
Sequences of the genomes of all-important bacterial pathogens of man, plants, and animals have been completed. Still, it is not enough to achieve complete information of all the mechanisms controlling the biological processes of an organism. Along with all advances in different proteomics technologies, proteomics has completed our knowledge of biological processes all around the world. Proteomics is a valuable technique to explain the complement of proteins in any organism. One of the fields that has been notably benefited from other systems approaches is bacterial pathogenesis. An emerging field is to use proteomics to examine the infectious agents in terms of, among many, the response the host and pathogen to the infection process, which leads to a deeper knowledge of the mechanisms of bacterial virulence. This trend also enables us to identify quantitative measurements for proteins extracted from microorganisms. The present review study is an attempt to summarize a variety of different proteomic techniques and advances. The significant applications in bacterial pathogenesis studies are also covered. Moreover, the areas where proteomics may lead the future studies are introduced.
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Affiliation(s)
- Ehsaneh Khodadadi
- Drug Applied Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Elham Zeinalzadeh
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.,Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sepehr Taghizadeh
- Drug Applied Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Bahareh Mehramouz
- Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Fadhil S Kamounah
- Department of Chemistry, University of Copenhagen, Copenhagen, DK 2100, Denmark
| | - Ehsan Khodadadi
- Department of Biology, Tabriz Branch, Islamic Azad University, Tabriz, Iran
| | | | - Bahman Yousefi
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Milad Bastami
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hossein Samadi Kafil
- Drug Applied Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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13
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Jani S, Sterzenbach K, Adatrao V, Tajbakhsh G, Mascher T, Golemi-Kotra D. Low phosphatase activity of LiaS and strong LiaR-DNA affinity explain the unusual LiaS to LiaR in vivo stoichiometry. BMC Microbiol 2020; 20:104. [PMID: 32349670 PMCID: PMC7191749 DOI: 10.1186/s12866-020-01796-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/20/2020] [Indexed: 11/20/2022] Open
Abstract
Background LiaRS mediates Bacillus subtilis response to cell envelope perturbations. A third protein, LiaF, has an inhibitory role over LiaRS in the absence of stimulus. Together, LiaF and LiaRS form a three-component system characterized by an unusual stoichiometry, a 4:1 ratio between LiaS and LiaR, the significance of which in the signal transduction mechanism of LiaRS is not entirely understood. Results We measured, for the first time, the kinetics of the phosphorylation-dependent processes of LiaRS, the DNA-binding affinity of LiaR, and characterized the effect of phosphorylation on LiaR oligomerization state. Our study reveals that LiaS is less proficient as a phosphatase. Consequently, unspecific phosphorylation of LiaR by acetyl phosphate may be significant in vivo. This drawback is exacerbated by the strong interaction between LiaR and its own promoter, as it can drive LiaRS into losing grip over its own control in the absence of stimuli. These intrinsic, seemingly ‘disadvantageous”, attributes of LiaRS are likely overcome by the higher concentration of LiaS over LiaR in vivo, and a pro-phosphatase role of LiaF. Conclusions Overall, our study shows that despite the conservative nature of two-component systems, they are, ultimately, tailored to meet specific cell needs by modulating the dynamics of interactions among their components and the kinetics of phosphorylation-mediated processes.
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Affiliation(s)
- Shailee Jani
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
| | - Karen Sterzenbach
- Institute for Microbiology, Technische Universität Dresden, Dresden, Germany
| | - Vijaya Adatrao
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
| | - Ghazal Tajbakhsh
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
| | - Thorsten Mascher
- Institute for Microbiology, Technische Universität Dresden, Dresden, Germany.
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14
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Popp PF, Benjdia A, Strahl H, Berteau O, Mascher T. The Epipeptide YydF Intrinsically Triggers the Cell Envelope Stress Response of Bacillus subtilis and Causes Severe Membrane Perturbations. Front Microbiol 2020; 11:151. [PMID: 32117169 PMCID: PMC7026026 DOI: 10.3389/fmicb.2020.00151] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/22/2020] [Indexed: 01/05/2023] Open
Abstract
The Gram-positive model organism and soil bacterium Bacillus subtilis naturally produces a variety of antimicrobial peptides (AMPs), including the ribosomally synthesized and post-translationally modified AMP YydF, which is encoded in the yydFGHIJ locus. The yydF gene encodes the pre-pro-peptide, which is, in a unique manner, initially modified at two amino acid positions by the radical SAM epimerase YydG. Subsequently, the membrane-anchored putative protease YydH is thought to cleave and release the mature AMP, YydF, to the environment. The AMP YydF, with two discreet epimerizations among 17 residues as sole post-translational modification, defines a novel class of ribosomally synthesized and post-translationally modified peptides (RiPPs) called epipeptides, for which the mode-of-action (MOA) is unknown. The predicted ABC transporter encoded by yydIJ was previously postulated as an autoimmunity determinant of B. subtilis against its own AMP. Here, we demonstrate that extrinsically added YydF* kills B. subtilis cells by dissipating membrane potential via membrane permeabilization. This severe membrane perturbation is accompanied by a rapid reduction of membrane fluidity, substantiated by lipid domain formation. The epipeptide triggers a narrow and highly specific cellular response. The strong induction of liaIH expression, a marker for cell envelope stress in B. subtilis, further supports the MOA described above. A subsequent mutational study demonstrates that LiaIH—and not YydIJ—represents the most efficient resistance determinant against YydF* action. Unexpectedly, none of the observed cellular effects upon YydF* treatment alone are able to trigger liaIH expression, indicating that only the unique combination of membrane permeabilization and membrane rigidification caused by the epipetide, leads to the observed cell envelope stress response.
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Affiliation(s)
- Philipp F Popp
- Institute of Microbiology, Technische Universität (TU) Dresden, Dresden, Germany
| | - Alhosna Benjdia
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | - Henrik Strahl
- Center for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Olivier Berteau
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität (TU) Dresden, Dresden, Germany
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15
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Gray DA, Wenzel M. More Than a Pore: A Current Perspective on the In Vivo Mode of Action of the Lipopeptide Antibiotic Daptomycin. Antibiotics (Basel) 2020; 9:E17. [PMID: 31947747 PMCID: PMC7168178 DOI: 10.3390/antibiotics9010017] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 12/29/2019] [Accepted: 12/31/2019] [Indexed: 12/19/2022] Open
Abstract
Daptomycin is a cyclic lipopeptide antibiotic, which was discovered in 1987 and entered the market in 2003. To date, it serves as last resort antibiotic to treat complicated skin infections, bacteremia, and right-sided endocarditis caused by Gram-positive pathogens, most prominently methicillin-resistant Staphylococcus aureus. Daptomycin was the last representative of a novel antibiotic class that was introduced to the clinic. It is also one of the few membrane-active compounds that can be applied systemically. While membrane-active antibiotics have long been limited to topical applications and were generally excluded from systemic drug development, they promise slower resistance development than many classical drugs that target single proteins. The success of daptomycin together with the emergence of more and more multi-resistant superbugs attracted renewed interest in this compound class. Studying daptomycin as a pioneering systemic membrane-active compound might help to pave the way for future membrane-targeting antibiotics. However, more than 30 years after its discovery, the exact mechanism of action of daptomycin is still debated. In particular, there is a prominent discrepancy between in vivo and in vitro studies. In this review, we discuss the current knowledge on the mechanism of daptomycin against Gram-positive bacteria and try to offer explanations for these conflicting observations.
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Affiliation(s)
- Declan Alan Gray
- Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK;
| | - Michaela Wenzel
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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16
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Minimal exposure of lipid II cycle intermediates triggers cell wall antibiotic resistance. Nat Commun 2019; 10:2733. [PMID: 31227716 PMCID: PMC6588590 DOI: 10.1038/s41467-019-10673-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 05/23/2019] [Indexed: 01/08/2023] Open
Abstract
Cell wall antibiotics are crucial for combatting the emerging wave of resistant bacteria. Yet, our understanding of antibiotic action is limited, as many strains devoid of all resistance determinants display far higher antibiotic tolerance in vivo than suggested by the antibiotic-target binding affinity in vitro. To resolve this conflict, here we develop a comprehensive theory for the bacterial cell wall biosynthetic pathway and study its perturbation by antibiotics. We find that the closed-loop architecture of the lipid II cycle of wall biosynthesis features a highly asymmetric distribution of pathway intermediates, and show that antibiotic tolerance scales inversely with the abundance of the targeted pathway intermediate. We formalize this principle of minimal target exposure as intrinsic resistance mechanism and predict how cooperative drug-target interactions can mitigate resistance. The theory accurately predicts the in vivo efficacy for various cell wall antibiotics in different Gram-positive bacteria and contributes to a systems-level understanding of antibiotic action.
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17
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McAuley S, Vadia S, Jani C, Huynh A, Yang Z, Levin PA, Nodwell JR. A Chemical Inhibitor of Cell Growth Reduces Cell Size in Bacillus subtilis. ACS Chem Biol 2019; 14:688-695. [PMID: 30848888 DOI: 10.1021/acschembio.8b01066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacteria exhibit complex responses to biologically active small molecules. These responses include reductions in transcriptional and translational efficiency, alterations in metabolic flux, and in some cases, dramatic changes in growth and morphology. Here, we describe Min-1, a novel small molecule that inhibits growth of Gram-positive bacteria by targeting the cell envelope. Subinhibitory levels of Min-1 inhibits sporulation in Streptomyces venezuelae and reduces growth rate and cell length in Bacillus subtilis. The effect of Min-1 on B. subtilis cell length is significant at high growth rates sustained by nutrient-rich media but drops off when growth rate is reduced during growth on less energy-rich carbon sources. In each medium, Min-1 has no impact on the proportion of cells containing FtsZ-rings, suggesting that Min-1 reduces the mass at which FtsZ assembly is initiated. The effect of Min-1 on size is independent of UDP-glucose, which couples cell division to carbon availability, and the alarmone ppGpp, which reduces cell size via its impact on fatty acid synthesis. Min-1 activates the LiaRS stress response, which is sensitive to disruptions in the lipid II cycle and the cell membrane, and also compromises cell membrane integrity. Therefore, this novel synthetic molecule inhibits growth at high concentrations and induces a short-cell phenotype at subinhibitory concentrations that is independent of known systems that influence cell length, highlighting the complex interactions between small molecules and cell morphology.
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Affiliation(s)
- Scott McAuley
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Stephen Vadia
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63105 United States
| | - Charul Jani
- Department of Biochemistry and Biomedical Sciences, Michael DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Alan Huynh
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Zhizhou Yang
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63105 United States
| | - Petra Anne Levin
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63105 United States
| | - Justin R. Nodwell
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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18
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Abstract
Daptomycin, a calcium-dependent lipopeptide antibiotic whose full mode of action is still not entirely understood, has become a standard-of-care agent for treating methicillin-resistant Staphylococcus aureus (MRSA) infections. Daptomycin-resistant (DAP-R) S. aureus mutants emerge during therapy, featuring isolates which in most cases possess point mutations in the mprF gene. MprF is a bifunctional bacterial resistance protein that synthesizes the positively charged lipid lysyl-phosphatidylglycerol (LysPG) and translocates it subsequently from the inner membrane leaflet to the outer membrane leaflet. This process leads to increased positive S. aureus surface charge and reduces susceptibility to cationic antimicrobial peptides and cationic antibiotics. We characterized the most commonly reported MprF mutations in DAP-R S. aureus strains in a defined genetic background and found that only certain mutations, including the frequently reported T345A single nucleotide polymorphism (SNP), can reproducibly cause daptomycin resistance. Surprisingly, T345A did not alter LysPG synthesis, LysPG translocation, or the S. aureus cell surface charge. MprF-mediated DAP-R relied on a functional flippase domain and was restricted to daptomycin and a related cyclic lipopeptide antibiotic, friulimicin B, suggesting that the mutations modulate specific interactions with these two antibiotics. Notably, the T345A mutation led to weakened intramolecular domain interactions of MprF, suggesting that daptomycin and friulimicin resistance-conferring mutations may alter the substrate range of the MprF flippase to directly translocate these lipopeptide antibiotics or other membrane components with crucial roles in the activity of these antimicrobials. Our study points to a new mechanism used by S. aureus to resist calcium-dependent lipopeptide antibiotics and increases our understanding of the bacterial phospholipid flippase MprF.IMPORTANCE Ever since daptomycin was introduced to the clinic, daptomycin-resistant isolates have been reported. In most cases, the resistant isolates harbor point mutations in MprF, which produces and flips the positively charged phospholipid LysPG. This has led to the assumption that the resistance mechanism relies on the overproduction of LysPG, given that increased LysPG production may lead to increased electrostatic repulsion of positively charged antimicrobial compounds, including daptomycin. Here we show that the resistance mechanism is highly specific and relies on a different process that involves a functional MprF flippase, suggesting that the resistance-conferring mutations may enable the flippase to accommodate daptomycin or an unknown component that is crucial for its activity. Our report provides a new perspective on the mechanism of resistance to a major antibiotic.
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19
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Müller A, Grein F, Otto A, Gries K, Orlov D, Zarubaev V, Girard M, Sher X, Shamova O, Roemer T, François P, Becher D, Schneider T, Sahl HG. Differential daptomycin resistance development in Staphylococcus aureus strains with active and mutated gra regulatory systems. Int J Med Microbiol 2017; 308:335-348. [PMID: 29429584 DOI: 10.1016/j.ijmm.2017.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 12/13/2017] [Accepted: 12/18/2017] [Indexed: 02/03/2023] Open
Abstract
The first-in-class lipopeptide antibiotic daptomycin (DAP) is highly active against Gram-positive pathogens including ß-lactam and glycopeptide resistant strains. Its molecular mode of action remains enigmatic, since a defined target has not been identified so far and multiple effects, primarily on the cell envelope have been observed. Reduced DAP susceptibility has been described in S. aureus and enterococci after prolonged treatment courses. In line with its pleiotropic antibiotic activities, a unique, defined molecular mechanism of resistance has not emerged, instead non-susceptibility appears often accompanied by alterations in membrane composition and changes in cell wall homeostasis. We compared S. aureus strains HG001 and SG511, which differ primarily in the functionality of the histidine kinase GraS, to evaluate the impact of the GraRS regulatory system on the development of DAP non-susceptibility. After extensive serial passing, both DAPR variants reached a minimal inhibitory concentration of 31 μg/ml and shared some phenotypic characteristics (e.g. thicker cell wall, reduced autolysis). However, based on comprehensive analysis of the underlying genetic, transcriptomic and proteomic changes, we found that both strains took different routes to achieve DAP resistance. Our study highlights the impressive genetic and physiological capacity of S. aureus to counteract pleiotropic activities of cell wall- and membrane-active compounds even when a major cell wall regulatory system is dysfunctional.
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Affiliation(s)
- Anna Müller
- Institute for Pharmaceutical Microbiology, University Hospital Bonn, University of Bonn, Bonn, Germany; German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn.
| | - Fabian Grein
- Institute for Pharmaceutical Microbiology, University Hospital Bonn, University of Bonn, Bonn, Germany; German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn
| | - Andreas Otto
- Institute for Microbiology, University of Greifswald, Greifswald, Germany
| | - Kathrin Gries
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Dmitriy Orlov
- Institute for Experimental Medicine, Saint Petersburg, Russia; Saint Petersburg University, Saint Petersburg, Russia
| | - Vladimir Zarubaev
- Pasteur Institute of Epidemiology and Microbiology, Saint Petersburg Russia
| | - Myriam Girard
- Genomic Research Laboratory, Department of Medical Specialties, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
| | - Xinwei Sher
- Merck & Co., Infectious Diseases, Kenilworth, NJ, USA
| | - Olga Shamova
- Institute for Experimental Medicine, Saint Petersburg, Russia; Saint Petersburg University, Saint Petersburg, Russia
| | | | - Patrice François
- Genomic Research Laboratory, Department of Medical Specialties, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
| | - Dörte Becher
- Institute for Microbiology, University of Greifswald, Greifswald, Germany
| | - Tanja Schneider
- Institute for Pharmaceutical Microbiology, University Hospital Bonn, University of Bonn, Bonn, Germany; German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn
| | - Hans-Georg Sahl
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn; Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, University of Bonn, Bonn, Germany
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20
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Woods EC, McBride SM. Regulation of antimicrobial resistance by extracytoplasmic function (ECF) sigma factors. Microbes Infect 2017; 19:238-248. [PMID: 28153747 DOI: 10.1016/j.micinf.2017.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/20/2017] [Accepted: 01/21/2017] [Indexed: 11/27/2022]
Abstract
Extracytoplasmic function (ECF) sigma factors are a subfamily of σ70 sigma factors that activate genes involved in stress-response functions. In many bacteria, ECF sigma factors regulate resistance to antimicrobial compounds. This review will summarize the ECF sigma factors that regulate antimicrobial resistance in model organisms and clinically relevant pathogens.
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Affiliation(s)
- Emily C Woods
- Department of Microbiology and Immunology, Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Shonna M McBride
- Department of Microbiology and Immunology, Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA, USA.
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21
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Abstract
Antibiotics represent a first line of defense of diverse microorganisms, which produce and use antibiotics to counteract natural enemies or competitors for nutritional resources in their nearby environment. For antimicrobial activity, nature has invented a great variety of mechanisms of antibiotic action that involve the perturbation of essential bacterial structures or biosynthesis pathways of macromolecules such as the bacterial cell wall, DNA, RNA, or proteins, thereby threatening the specific microbial lifestyle and eventually even survival. However, along with highly inventive modes of antibiotic action, nature also developed a comparable set of resistance mechanisms that help the bacteria to circumvent antibiotic action. Microorganisms have evolved specific adaptive responses that allow appropriately reacting to the presence of antimicrobial agents, ensuring survival during antimicrobial stress. In times of rapid development and spread of antibiotic (multi-)resistance, we need to explore new, resistance-breaking strategies to counteract bacterial infections. This chapter intends to give an overview of common antibiotics and their target pathways. It will also discuss recent advances in finding new antibiotics with novel modes of action, illustrating that nature's repertoire of innovative new antimicrobial agents has not been fully exploited yet, and we still might find new drugs that help to evade established antimicrobial resistance strategies.
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Affiliation(s)
- Peter Sass
- Interfaculty Institute for Microbiology and Infection Medicine, Microbial Bioactive Compounds, University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany.
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22
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The action mechanism of daptomycin. Bioorg Med Chem 2016; 24:6253-6268. [DOI: 10.1016/j.bmc.2016.05.052] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/20/2016] [Accepted: 05/26/2016] [Indexed: 11/15/2022]
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23
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Daptomycin inhibits cell envelope synthesis by interfering with fluid membrane microdomains. Proc Natl Acad Sci U S A 2016; 113:E7077-E7086. [PMID: 27791134 DOI: 10.1073/pnas.1611173113] [Citation(s) in RCA: 269] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Daptomycin is a highly efficient last-resort antibiotic that targets the bacterial cell membrane. Despite its clinical importance, the exact mechanism by which daptomycin kills bacteria is not fully understood. Different experiments have led to different models, including (i) blockage of cell wall synthesis, (ii) membrane pore formation, and (iii) the generation of altered membrane curvature leading to aberrant recruitment of proteins. To determine which model is correct, we carried out a comprehensive mode-of-action study using the model organism Bacillus subtilis and different assays, including proteomics, ionomics, and fluorescence light microscopy. We found that daptomycin causes a gradual decrease in membrane potential but does not form discrete membrane pores. Although we found no evidence for altered membrane curvature, we confirmed that daptomycin inhibits cell wall synthesis. Interestingly, using different fluorescent lipid probes, we showed that binding of daptomycin led to a drastic rearrangement of fluid lipid domains, affecting overall membrane fluidity. Importantly, these changes resulted in the rapid detachment of the membrane-associated lipid II synthase MurG and the phospholipid synthase PlsX. Both proteins preferentially colocalize with fluid membrane microdomains. Delocalization of these proteins presumably is a key reason why daptomycin blocks cell wall synthesis. Finally, clustering of fluid lipids by daptomycin likely causes hydrophobic mismatches between fluid and more rigid membrane areas. This mismatch can facilitate proton leakage and may explain the gradual membrane depolarization observed with daptomycin. Targeting of fluid lipid domains has not been described before for antibiotics and adds another dimension to our understanding of membrane-active antibiotics.
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24
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Tran TT, Miller WR, Shamoo Y, Arias CA. Targeting cell membrane adaptation as a novel antimicrobial strategy. Curr Opin Microbiol 2016; 33:91-96. [PMID: 27458841 DOI: 10.1016/j.mib.2016.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/01/2016] [Accepted: 07/05/2016] [Indexed: 01/19/2023]
Abstract
Emergence of antibiotic resistance is an example of the incredible plasticity of bacteria to survive in all environments. The search for new antibiotics active against traditional targets is more challenging due not only to the lack of novel natural products to fulfill the current clinical needs against multidrug-resistant (MDR) bacteria, but also for the possible 'collateral' effects on the human microbiota. Thus, non-traditional approaches to combat MDR bacteria have been proposed. Here, we discuss the possibility of targeting the membrane response to the antibiotic attack (cell membrane adaptation) as a viable strategy to increase the activity of current antimicrobials, enhance the activity of the innate immune system and prevent development of resistance during therapy using the three-component regulatory system LiaFSR of enterococci as a model.
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Affiliation(s)
- Truc T Tran
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas McGovern Medical School, Houston, TX, United States; Center for Antibiotic Resistance and Microbial Genomics, University of Texas McGovern Medical School, Houston, TX, United States
| | - William R Miller
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas McGovern Medical School, Houston, TX, United States; Center for Antibiotic Resistance and Microbial Genomics, University of Texas McGovern Medical School, Houston, TX, United States
| | - Yousif Shamoo
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX, United States
| | - Cesar A Arias
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas McGovern Medical School, Houston, TX, United States; Center for Antibiotic Resistance and Microbial Genomics, University of Texas McGovern Medical School, Houston, TX, United States; Molecular Genetics and Antimicrobial Resistance Unit, Universidad El Bosque, Bogota, Colombia; International Center for Microbial Genomics, Universidad El Bosque, Bogota, Colombia.
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25
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Radeck J, Fritz G, Mascher T. The cell envelope stress response of Bacillus subtilis: from static signaling devices to dynamic regulatory network. Curr Genet 2016; 63:79-90. [PMID: 27344142 DOI: 10.1007/s00294-016-0624-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 11/24/2022]
Abstract
The cell envelope stress response (CESR) encompasses all regulatory events that enable a cell to protect the integrity of its envelope, an essential structure of any bacterial cell. The underlying signaling network is particularly well understood in the Gram-positive model organism Bacillus subtilis. It consists of a number of two-component systems (2CS) and extracytoplasmic function σ factors that together regulate the production of both specific resistance determinants and general mechanisms to protect the envelope against antimicrobial peptides targeting the biogenesis of the cell wall. Here, we summarize the current picture of the B. subtilis CESR network, from the initial identification of the corresponding signaling devices to unraveling their interdependence and the underlying regulatory hierarchy within the network. In the course of detailed mechanistic studies, a number of novel signaling features could be described for the 2CSs involved in mediating CESR. This includes a novel class of so-called intramembrane-sensing histidine kinases (IM-HKs), which-instead of acting as stress sensors themselves-are activated via interprotein signal transfer. Some of these IM-HKs are involved in sensing the flux of antibiotic resistance transporters, a unique mechanism of responding to extracellular antibiotic challenge.
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Affiliation(s)
- Jara Radeck
- Institute of Microbiology, Technische Universität (TU) Dresden, Dresden, Germany
| | - Georg Fritz
- LOEWE-Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität (TU) Dresden, Dresden, Germany.
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26
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Wolf D, Mascher T. The applied side of antimicrobial peptide-inducible promoters from Firmicutes bacteria: expression systems and whole-cell biosensors. Appl Microbiol Biotechnol 2016; 100:4817-29. [PMID: 27102123 DOI: 10.1007/s00253-016-7519-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 03/23/2016] [Accepted: 03/25/2016] [Indexed: 11/28/2022]
Abstract
The cell envelope is an essential bacterial structure that consists of the cytoplasmic membrane, the cell wall, and-in Gram-negative bacteria-the outer membrane. Because of its crucial functions, it represents a prime antibiotic target. Monitoring and maintaining its integrity are therefore keys to survival, especially in competitive environments where antibiotics represent one means of suppressing the growth of competitors. Resistance against external antibiotic threat, as well as auto-immunity against self-produced antibiotics, is often mediated by two-component systems (2CSs). They respond to antibiotic threat by inducing gene expression that results in the production of specific resistance determinants. The underlying transcriptional control is exhibited at the level of specific target promoters, which usually share a number of relevant features: They are tightly controlled and only induced in the presence of specific (sets of) antibiotics. This induction is dose dependent and often very sensitive, that is, it occurs well below inhibitory antibiotic concentrations. Because of these characteristics, a number of well-characterized cell envelope stress-inducible promoters have been developed for two different applied purposes: first, as whole-cell biosensors for antibiotic detection and mechanism-of-action studies, and second, as antibiotic-inducible expression systems for biotechnological purposes. The current state of research in both fields will be discussed in this review, focusing on 2CS-regulated promoters from Firmicutes bacteria that are induced to mediate resistance against antimicrobial peptides (AMPs) targeting the cell envelope.
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Affiliation(s)
- Diana Wolf
- Institute of Microbiology, Technische Universität (TU) Dresden, 01062, Dresden, Germany
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität (TU) Dresden, 01062, Dresden, Germany.
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27
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Radeck J, Gebhard S, Orchard PS, Kirchner M, Bauer S, Mascher T, Fritz G. Anatomy of the bacitracin resistance network inBacillus subtilis. Mol Microbiol 2016; 100:607-20. [DOI: 10.1111/mmi.13336] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2016] [Indexed: 12/23/2022]
Affiliation(s)
- Jara Radeck
- Technische Universität Dresden, Institute of Microbiology; Dresden Germany
- Ludwig-Maximilians-Universität Mänchen, Department Biology I; Mänchen Germany
| | - Susanne Gebhard
- University of Bath, Department of Biology and Biochemistry, Milner Centre for Evolution; Bath United Kingdom
| | | | - Marion Kirchner
- Ludwig-Maximilians-Universität Mänchen, Department Biology I; Mänchen Germany
| | - Stephanie Bauer
- Ludwig-Maximilians-Universität Mänchen, Department Biology I; Mänchen Germany
| | - Thorsten Mascher
- Technische Universität Dresden, Institute of Microbiology; Dresden Germany
| | - Georg Fritz
- Philipps-Universität Marburg, LOEWE-Center for Synthetic Microbiology (SYNMIKRO); Marburg Germany
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Molohon KJ, Saint-Vincent PMB, Park S, Doroghazi JR, Maxson T, Hershfield JR, Flatt KM, Schroeder NE, Ha T, Mitchell DA. Plantazolicin is an ultra-narrow spectrum antibiotic that targets the Bacillus anthracis membrane. ACS Infect Dis 2016; 2:207-220. [PMID: 27152321 DOI: 10.1021/acsinfecdis.5b00115] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Plantazolicin (PZN) is a ribosomally synthesized and post-translationally modified natural product from Bacillus methylotrophicus FZB42 and Bacillus pumilus. Extensive tailoring to twelve of the fourteen amino acid residues in the mature natural product endows PZN with not only a rigid, polyheterocyclic structure, but also antibacterial activity. Here we report a remarkably discriminatory activity of PZN toward Bacillus anthracis, which rivals a previously-described gamma (γ) phage lysis assay in distinguishing B. anthracis from other members of the Bacillus cereus group. We evaluate the underlying cause of this selective activity by measuring the RNA expression profile of PZN-treated B. anthracis, which revealed significant upregulation of genes within the cell envelope stress response. PZN depolarizes the B. anthracis membrane like other cell envelope-acting compounds but uniquely localizes to distinct foci within the envelope. Selection and whole-genome sequencing of PZN-resistant mutants of B. anthracis implicate a relationship between the action of PZN and cardiolipin (CL) within the membrane. Exogenous CL increases the potency of PZN in wild type B. anthracis and promotes the incorporation of fluorescently tagged PZN in the cell envelope. We propose that PZN localizes to and exacerbates structurally compromised regions of the bacterial membrane, which ultimately results in cell lysis.
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Affiliation(s)
- Katie J. Molohon
- Department of Microbiology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | | | - Seongjin Park
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - James R. Doroghazi
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Tucker Maxson
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Jeremy R. Hershfield
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, United States
| | - Kristen M. Flatt
- Department of Crop Sciences, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Nathan E. Schroeder
- Department of Crop Sciences, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Taekjip Ha
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, United States
| | - Douglas A. Mitchell
- Department of Microbiology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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29
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Helmann JD. Bacillus subtilis extracytoplasmic function (ECF) sigma factors and defense of the cell envelope. Curr Opin Microbiol 2016; 30:122-132. [PMID: 26901131 DOI: 10.1016/j.mib.2016.02.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 01/29/2016] [Accepted: 02/02/2016] [Indexed: 01/20/2023]
Abstract
Bacillus subtilis provides a model for investigation of the bacterial cell envelope, the first line of defense against environmental threats. Extracytoplasmic function (ECF) sigma factors activate genes that confer resistance to agents that threaten the integrity of the envelope. Although their individual regulons overlap, σ(W) is most closely associated with membrane-active agents, σ(X) with cationic antimicrobial peptide resistance, and σ(V) with resistance to lysozyme. Here, I highlight the role of the σ(M) regulon, which is strongly induced by conditions that impair peptidoglycan synthesis and includes the core pathways of envelope synthesis and cell division, as well as stress-inducible alternative enzymes. Studies of these cell envelope stress responses provide insights into how bacteria acclimate to the presence of antibiotics.
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Affiliation(s)
- John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA.
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30
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References. Antibiotics (Basel) 2015. [DOI: 10.1128/9781555819316.refs] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Abstract
Daptomycin (DAP) is a cyclic lipopeptide with in vitro activity against a variety of Gram-positive pathogens, including multidrug-resistant organisms. Since its introduction into clinical practice in 2003, DAP has become an important key frontline antibiotic for severe or deep-seated infections caused by Gram-positive organisms. Unfortunately, DAP resistance (DAP-R) has been extensively documented in clinically important organisms such as Staphylococcus aureus, Enterococcus spp., and Streptococcus spp. Studies on the mechanisms of DAP-R in Bacillus subtilis and other Gram-positive bacteria indicate that the genetic pathways of DAP-R are diverse and complex. However, a common phenomenon emerging from these mechanistic studies is that DAP-R is associated with important adaptive changes in cell wall and cell membrane homeostasis with critical changes in cell physiology. Findings related to these adaptive changes have provided novel insights into the genetics and molecular mechanisms of bacterial cell envelope stress response and the manner in which Gram-positive bacteria cope with the antimicrobial peptide attack and protect vital structures of the cell envelope, such as the cell membrane. In this review, we will examine the most recent findings related to the molecular mechanisms of resistance to DAP in relevant Gram-positive pathogens and discuss the clinical implications for therapy against these important bacteria.
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Affiliation(s)
- Truc T Tran
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School at Houston, Houston, Texas.,International Center for Microbial Genomics, Universidad El Bosque, Bogota, Colombia
| | - Jose M Munita
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School at Houston, Houston, Texas.,International Center for Microbial Genomics, Universidad El Bosque, Bogota, Colombia.,Clinica Alemana de Santiago, Universidad del Desarrollo, Santiago, Chile
| | - Cesar A Arias
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School at Houston, Houston, Texas.,International Center for Microbial Genomics, Universidad El Bosque, Bogota, Colombia.,Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, Texas.,Molecular Genetics and Antimicrobial Resistance Unit, Universidad El Bosque, Bogota, Colombia
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32
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Yu WB, Ye BC. High-level iron mitigates fusaricidin-induced membrane damage and reduces membrane fluidity leading to enhanced drug resistance inBacillus subtilis. J Basic Microbiol 2015; 56:502-9. [DOI: 10.1002/jobm.201500291] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/29/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Wen-Bang Yu
- Lab of Biosystems and Microanalysis; State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology; Shanghai China
| | - Bang-Ce Ye
- Lab of Biosystems and Microanalysis; State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology; Shanghai China
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33
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Lee CR, Lee JH, Park KS, Jeong BC, Lee SH. Quantitative proteomic view associated with resistance to clinically important antibiotics in Gram-positive bacteria: a systematic review. Front Microbiol 2015; 6:828. [PMID: 26322035 PMCID: PMC4531251 DOI: 10.3389/fmicb.2015.00828] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 07/27/2015] [Indexed: 11/13/2022] Open
Abstract
The increase of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) poses a worldwide and serious health threat. Although new antibiotics, such as daptomycin and linezolid, have been developed for the treatment of infections of Gram-positive pathogens, the emergence of daptomycin-resistant and linezolid-resistant strains during therapy has now increased clinical treatment failures. In the past few years, studies using quantitative proteomic methods have provided a considerable progress in understanding antibiotic resistance mechanisms. In this review, to understand the resistance mechanisms to four clinically important antibiotics (methicillin, vancomycin, linezolid, and daptomycin) used in the treatment of Gram-positive pathogens, we summarize recent advances in studies on resistance mechanisms using quantitative proteomic methods, and also examine proteins playing an important role in the bacterial mechanisms of resistance to the four antibiotics. Proteomic researches can identify proteins whose expression levels are changed in the resistance mechanism to only one antibiotic, such as LiaH in daptomycin resistance and PrsA in vancomycin resistance, and many proteins simultaneously involved in resistance mechanisms to various antibiotics. Most of resistance-related proteins, which are simultaneously associated with resistance mechanisms to several antibiotics, play important roles in regulating bacterial envelope biogenesis, or compensating for the fitness cost of antibiotic resistance. Therefore, proteomic data confirm that antibiotic resistance requires the fitness cost and the bacterial envelope is an important factor in antibiotic resistance.
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Affiliation(s)
- Chang-Ro Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Jung Hun Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Kwang Seung Park
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Byeong Chul Jeong
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Sang Hee Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
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34
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Two-component system YvqEC-dependent bacterial resistance against vancomycin in Bacillus thuringiensis. Antonie van Leeuwenhoek 2015; 108:365-76. [PMID: 26025304 DOI: 10.1007/s10482-015-0489-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 05/19/2015] [Indexed: 02/06/2023]
Abstract
YvqEC is one of the two-component signal transduction systems that may respond to cell envelope stress and enable cells to adjust multiple cellular functions. It consists of a histidine kinase YvqE and a response regulator YvqC. In this study, we separately constructed a single gene mutant ΔyvqE and a double gene mutant ΔyvqEC in Bacillus thuringiensis BMB171 through a homing endonucleases I-SceI mediated markerless gene deletion method. We found that the deletion of either yvqE or yvqEC weakened the resistance of B. thuringiensis against vancomycin. We also identified nine operons that may be involved in the cellular metabolism regulated by YvqC. This study not only enriches our understanding of bacterial resistance mechanisms against vancomycin, but also helps investigate the functions of YvqEC.
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35
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Small cationic antimicrobial peptides delocalize peripheral membrane proteins. Proc Natl Acad Sci U S A 2014; 111:E1409-18. [PMID: 24706874 DOI: 10.1073/pnas.1319900111] [Citation(s) in RCA: 250] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Short antimicrobial peptides rich in arginine (R) and tryptophan (W) interact with membranes. To learn how this interaction leads to bacterial death, we characterized the effects of the minimal pharmacophore RWRWRW-NH2. A ruthenium-substituted derivative of this peptide localized to the membrane in vivo, and the peptide also integrated readily into mixed phospholipid bilayers that resemble Gram-positive membranes. Proteome and Western blot analyses showed that integration of the peptide caused delocalization of peripheral membrane proteins essential for respiration and cell-wall biosynthesis, limiting cellular energy and undermining cell-wall integrity. This delocalization phenomenon also was observed with the cyclic peptide gramicidin S, indicating the generality of the mechanism. Exogenous glutamate increases tolerance to the peptide, indicating that osmotic destabilization also contributes to antibacterial efficacy. Bacillus subtilis responds to peptide stress by releasing osmoprotective amino acids, in part via mechanosensitive channels. This response is triggered by membrane-targeting bacteriolytic peptides of different structural classes as well as by hypoosmotic conditions.
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36
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A putative bactoprenol glycosyltransferase, CsbB, in Bacillus subtilis activates SigM in the absence of co-transcribed YfhO. Biochem Biophys Res Commun 2013; 436:6-11. [PMID: 23632331 DOI: 10.1016/j.bbrc.2013.04.064] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 04/22/2013] [Indexed: 11/21/2022]
Abstract
Bacteria are equipped with complex cell surface structures, such as cell walls. How they maintain cell surface integrity through cell wall metabolism during growth and adaptation to unfavorable environmental conditions is still elusive. In the Gram-positive soil bacterium Bacillus subtilis, one extracytoplasmic function (ECF) sigma factor, SigM, is believed to play a primary role in cell surface integrity. Here, we find that expression of CsbB, which is known to be involved in the extracellular stress response, causes constitutive activation of SigM when YfhO, a membrane protein with unknown function, is lost. CsbB has similarity with the well-characterized bactoprenol glucosyltransferase GtrB found in Gram-negative bacteria. Substitution of a single amino acid residue at the putative catalytic site of CsbB abolishes this constitutive activation, and expression of Escherichia coli GtrB in B. subtilis causes similar effects as expression of CsbB, suggesting that SigM is activated by the glycosyltransferase activity of CsbB. A comparison with the Gtr system in Gram-negative bacteria suggests that accumulation of glycosylated bactoprenol catalyzed by CsbB reduces the bactoprenol pool in the absence of YfhO. Reduction of bactoprenol synthesis causes similar effects as expression of CsbB. We propose that it is the shortage of available bactoprenol within a cell that induces SigM activity.
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37
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Fränzel B, Penkova M, Frese C, Metzler-Nolte N, Andreas Wolters D. Escherichia coli exhibits a membrane-related response to a small arginine- and tryptophan-rich antimicrobial peptide. Proteomics 2013; 12:2319-30. [PMID: 22685012 DOI: 10.1002/pmic.201100636] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Since multiresistant bacterial strains are more widespread and the victim numbers steadily increase, it is very important to possess a broad bandwidth of antimicrobial substances. Antibiotics often feature membrane-associated effect mechanisms. So, we present a membrane proteomic approach to shed light on the cellular response of Escherichia coli as model organism to the hexapeptide MP196, which is arginine and tryptophan rich. Analyzing integral membrane proteins are still challenging, although various detection strategies have been developed in the past. In particular, membrane proteomics in bacteria have been conducted very little due to the special physical properties of these membrane proteins. To obtain more information on the cellular response of the new compound group of small peptides, the tryptophan- and arginine-rich hexapeptide MP196 was subject to a comprehensive quantitative membrane proteomic study on E. coli by means of metabolic labeling in combination with membrane lipid analyses. This study provides in total 767 protein identifications including 185 integral membrane proteins, from which 624 could be quantified. Among these proteins, 134 were differentially expressed. Thereby, functional groups such as amino acid and membrane biosynthesis were affected, stress response could be observed, and the lipid composition of the membrane was significantly altered. Especially, the strong upregulation of the envelope stress induced protein. Spy indicates membrane damage, as well as the downregulation of the mechano-sensitive channel MscL beside others. Finally, the exceptional downregulation of transport systems strengthens these findings.
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Affiliation(s)
- Benjamin Fränzel
- Lehrstuhl für Analytische Chemie, Biomolekulare Massenspektrometrie, Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Bochum, Germany
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38
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Lima TB, Pinto MFS, Ribeiro SM, de Lima LA, Viana JC, Gomes Júnior N, Cândido EDS, Dias SC, Franco OL. Bacterial resistance mechanism: what proteomics can elucidate. FASEB J 2013; 27:1291-303. [PMID: 23349550 DOI: 10.1096/fj.12-221127] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Antibiotics are important therapeutic agents commonly used for the control of bacterial infectious diseases; however, resistance to antibiotics has become a global public health problem. Therefore, effective therapy in the treatment of resistant bacteria is necessary and, to achieve this, a detailed understanding of mechanisms that underlie drug resistance must be sought. To fill the multiple gaps that remain in understanding bacterial resistance, proteomic tools have been used to study bacterial physiology in response to antibiotic stress. In general, the global analysis of changes in the protein composition of bacterial cells in response to treatment with antibiotic agents has made it possible to construct a database of proteins involved in the process of resistance to drugs with similar mechanisms of action. In the past few years, progress in using proteomic tools has provided the most realistic picture of the infective process, since these tools detect the end products of gene biosynthetic pathways, which may eventually determine a biological phenotype. In most bacterial species, alterations occur in energy and nitrogen metabolism regulation; glucan biosynthesis is up-regulated; amino acid, protein, and nucleotide synthesis is affected; and various proteins show a stress response after exposing these microorganisms to antibiotics. These issues have been useful in identifying targets for the development of novel antibiotics and also in understanding, at the molecular level, how bacteria resist antibiotics.
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Affiliation(s)
- Thais Bergamin Lima
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasilia, Brazil
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39
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Schrecke K, Jordan S, Mascher T. Stoichiometry and perturbation studies of the LiaFSR system ofBacillus subtilis. Mol Microbiol 2013; 87:769-88. [DOI: 10.1111/mmi.12130] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2012] [Indexed: 01/18/2023]
Affiliation(s)
- Karen Schrecke
- Department of Biology I; Ludwig-Maximilians-University Munich; Munich; Germany
| | - Sina Jordan
- Department of Biology I; Ludwig-Maximilians-University Munich; Munich; Germany
| | - Thorsten Mascher
- Department of Biology I; Ludwig-Maximilians-University Munich; Munich; Germany
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40
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Bayer AS, Schneider T, Sahl HG. Mechanisms of daptomycin resistance in Staphylococcus aureus: role of the cell membrane and cell wall. Ann N Y Acad Sci 2013; 1277:139-58. [PMID: 23215859 PMCID: PMC3556211 DOI: 10.1111/j.1749-6632.2012.06819.x] [Citation(s) in RCA: 220] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The bactericidal, cell membrane-targeting lipopeptide antibiotic daptomycin (DAP) is an important agent in treating invasive Staphylococcus aureus infections. However, there have been numerous recent reports of development of daptomycin resistance (DAP-R) during therapy with this agent. The mechanisms of DAP-R in S. aureus appear to be quite diverse. DAP-R strains often exhibit progressive accumulation of single nucleotide polymorphisms in the multipeptide resistance factor gene (mprF) and the yycFG components of the yycFGHI operon. Both loci are involved in key cell membrane (CM) events, with mprF being responsible for the synthesis and outer CM translocation of the positively charged phospholipid, lysyl-phosphotidylglycerol (L-PG), while the yyc operon is involved in the generalized response to stressors such as antimicrobials. In addition, other perturbations of the CM have been identified in DAP-R strains, including extremes in CM order, resistance to CM depolarization and permeabilization, and reduced surface binding of DAP. Moreover, modifications of the cell wall (CW) appear to also contribute to DAP-R, including enhanced expression of the dlt operon (involved in d-alanylation of CW teichoic acids) and progressive CW thickening.
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Affiliation(s)
- Arnold S Bayer
- Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles, Torrance, California 905092, USA.
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41
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Wenzel M, Kohl B, Münch D, Raatschen N, Albada HB, Hamoen L, Metzler-Nolte N, Sahl HG, Bandow JE. Proteomic response of Bacillus subtilis to lantibiotics reflects differences in interaction with the cytoplasmic membrane. Antimicrob Agents Chemother 2012; 56:5749-57. [PMID: 22926563 PMCID: PMC3486579 DOI: 10.1128/aac.01380-12] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 08/16/2012] [Indexed: 12/17/2022] Open
Abstract
Mersacidin, gallidermin, and nisin are lantibiotics, antimicrobial peptides containing lanthionine. They show potent antibacterial activity. All three interfere with cell wall biosynthesis by binding lipid II, but they display different levels of interaction with the cytoplasmic membrane. On one end of the spectrum, mersacidin interferes with cell wall biosynthesis by binding lipid II without integrating into bacterial membranes. On the other end of the spectrum, nisin readily integrates into membranes, where it forms large pores. It destroys the membrane potential and causes leakage of nutrients and ions. Gallidermin, in an intermediate position, also readily integrates into membranes. However, pore formation occurs only in some bacteria and depends on membrane composition. In this study, we investigated the impact of nisin, gallidermin, and mersacidin on cell wall integrity, membrane pore formation, and membrane depolarization in Bacillus subtilis. The impact of the lantibiotics on the cell envelope was correlated to the proteomic response they elicit in B. subtilis. By drawing on a proteomic response library, including other envelope-targeting antibiotics such as bacitracin, vancomycin, gramicidin S, or valinomycin, YtrE could be identified as the most reliable marker protein for interfering with membrane-bound steps of cell wall biosynthesis. NadE and PspA were identified as markers for antibiotics interacting with the cytoplasmic membrane.
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Affiliation(s)
- Michaela Wenzel
- Biology of Microorganisms, Ruhr University Bochum, Bochum, Germany
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42
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Cell envelope stress response in cell wall-deficient L-forms of Bacillus subtilis. Antimicrob Agents Chemother 2012; 56:5907-15. [PMID: 22964256 DOI: 10.1128/aac.00770-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
L-forms are cell wall-deficient bacteria that can grow and proliferate in osmotically stabilizing media. Recently, a strain of the Gram-positive model bacterium Bacillus subtilis was constructed that allowed controlled switching between rod-shaped wild-type cells and corresponding L-forms. Both states can be stably maintained under suitable culture conditions. Because of the absence of a cell wall, L-forms are known to be insensitive to β-lactam antibiotics, but reports on the susceptibility of L-forms to other antibiotics that interfere with membrane-anchored steps of cell wall biosynthesis are sparse, conflicting, and strongly influenced by strain background and method of L-form generation. Here we investigated the response of B. subtilis to the presence of cell envelope antibiotics, with regard to both antibiotic resistance and the induction of the known LiaRS- and BceRS-dependent cell envelope stress biosensors. Our results show that B. subtilis L-forms are resistant to antibiotics that interfere with the bactoprenol cycle, such as bacitracin, vancomycin, and mersacidin, but are hypersensitive to nisin and daptomycin, which both affect membrane integrity. Moreover, we established a lacZ-based reporter gene assay for L-forms and provide evidence that LiaRS senses its inducers indirectly (damage sensing), while the Bce module detects its inducers directly (drug sensing).
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43
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Raatschen N, Elisabeth Bandow J. 2‐D Gel‐Based Proteomic Approaches to Antibiotic Drug Discovery. ACTA ACUST UNITED AC 2012; Chapter 1:Unit1F.2. [DOI: 10.1002/9780471729259.mc01f02s26] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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44
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Mishra BB, Tiwari VK. Natural products: An evolving role in future drug discovery. Eur J Med Chem 2011; 46:4769-807. [DOI: 10.1016/j.ejmech.2011.07.057] [Citation(s) in RCA: 565] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 07/29/2011] [Accepted: 07/30/2011] [Indexed: 11/16/2022]
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45
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Wecke T, Mascher T. Antibiotic research in the age of omics: from expression profiles to interspecies communication. J Antimicrob Chemother 2011; 66:2689-704. [DOI: 10.1093/jac/dkr373] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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46
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Model membrane approaches to determine the role of calcium for the antimicrobial activity of friulimicin. Int J Antimicrob Agents 2011; 37:256-60. [PMID: 21306875 DOI: 10.1016/j.ijantimicag.2010.11.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 11/05/2010] [Accepted: 11/12/2010] [Indexed: 11/23/2022]
Abstract
Friulimicin is a cyclic lipopeptide antibiotic, currently in clinical development, that possesses excellent activity against Gram-positive bacteria, including multiresistant strains. A recent study on the mode of action of friulimicin reported on the interference with bacterial cell wall biosynthesis via a calcium-dependent complexing of the bactoprenol phosphate carrier C₅₅-P. The calcium dependency of this non-common targeted activity remains to be elucidated. In the present model membrane approach, the role of calcium for friulimicin targeting to C₅₅-P was investigated by biosensor-based detection of binding affinities. The findings were supplemented by atomic force microscopy (AFM) and circular dichroism (CD) spectroscopy. Comparing the calcium salt of friulimicin with the calcium-free peptide, calcium appeared to be essential for friulimicin interaction with DOPC model membranes. The binding affinity was even higher in the presence of 0.1 mol% C₅₅-P (0.21 μM vs. 1.22 μM), confirming the targeted mode of action. Binding experiments with supplemented calcium salts suggest (i) the phosphate group as the essential moiety of C₅₅-P, referring to a bridging function of calcium between the negatively charged friulimicin and C₅₅-P, and (ii) a structural effect of calcium shifting the peptide into a suitable binding conformation (CD spectra). AFM images confirmed that calcium has no, or only a minor, effect on the aggregate formation of friulimicin. These data shed new light on the mechanisms of antibacterial activity of friulimicin.
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47
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Wecke T, Bauer T, Harth H, Mäder U, Mascher T. The rhamnolipid stress response of Bacillus subtilis. FEMS Microbiol Lett 2011; 323:113-23. [PMID: 22092710 DOI: 10.1111/j.1574-6968.2011.02367.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 07/20/2011] [Accepted: 07/21/2011] [Indexed: 12/29/2022] Open
Abstract
Rhamnolipids are biosurfactants produced by the soil bacterium P seudomonas aeruginosa. In addition to their high industrial potential as surface-active molecules, rhamnolipids also have antimicrobial properties. In densely populated habitats, such as the soil, production of antimicrobial compounds is important to inhibit growth of competitors. For the latter, it is crucial for survival to sense and respond to the presence of those antibiotics. To gain a first insight into the biological competition involving biosurfactants, we investigated the cellular response of the model organism B acillus subtilis upon exposure to rhamnolipids by genome-wide transcriptional profiling. Most of the differentially expressed genes can be assigned to two different regulatory networks: the cell envelope stress response mediated by the two-component system LiaRS and the extracytoplasmic function σ factor σ(M) and the CssRS-dependent secretion stress response. Subsequent phenotypic analysis demonstrated a protective function of LiaRS and σ(M) against cell lysis caused by rhamnolipids. Taken together, we present the first evidence that a single antimicrobial compound can simultaneously induce genes from two independent stress stimulons.
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Affiliation(s)
- Tina Wecke
- Department of Biology I, Ludwig-Maximilians-University, Munich, Germany
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Wenzel M, Bandow JE. Proteomic signatures in antibiotic research. Proteomics 2011; 11:3256-68. [DOI: 10.1002/pmic.201100046] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/13/2011] [Accepted: 03/22/2011] [Indexed: 11/06/2022]
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Molecular cloning and identification of the laspartomycin biosynthetic gene cluster from Streptomyces viridochromogenes. Gene 2011; 483:11-21. [PMID: 21640802 DOI: 10.1016/j.gene.2011.05.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 05/10/2011] [Accepted: 05/10/2011] [Indexed: 11/21/2022]
Abstract
The biosynthetic gene cluster for laspartomycins, a family of 11 amino acid peptide antibiotics, has been cloned and sequenced from Streptomyces viridochromogenes ATCC 29814. Annotation of a segment of 88912bp of S. viridochromogenes genomic sequence revealed the putative lpm cluster and its flanking regions which harbor 43 open reading frames. The lpm cluster, which spans approximately 60 kb, consists of 21 open reading frames. Those include four NRPS genes (lpmA/orf18, lpmB/orf25, lpmC/orf26 and lpmD/orf27), four genes (orfs 21, 22, 24 and 29) involved in the lipid tail biosynthesis and attachment, four regulatory genes (orfs 13, 19, 32 and 33) and three putative exporters or self-resistance genes (orfs 14, 20 and 30). In addition, the gene involved in the biosynthesis of the nonproteinogenic amino acid Pip was also identified in the lpm cluster while the genes necessary for the biosynthesis of the rare residue diaminopropionic acid (Dap) were found to reside elsewhere on the chromosome. Interestingly, the dabA, dabB and dabC genes predicted to code for the biosynthesis of the unusual amino acid diaminobutyric acid (Dab) are organized into the lpm cluster even though the Dab residue was not found in the laspartomycins. Disruption of the NRPS lpmC gene completely abolished laspartomycin production in the corresponding mutant strain. These findings will allow molecular engineering and combinatorial biosynthesis approaches to expand the structural diversity of the amphomycin-group peptide antibiotics including the laspartomycins and friulimicins.
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Peptide antibiotic sensing and detoxification modules of Bacillus subtilis. Antimicrob Agents Chemother 2010; 55:515-25. [PMID: 21078927 DOI: 10.1128/aac.00352-10] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peptide antibiotics are produced by a wide range of microorganisms. Most of them target the cell envelope, often by inhibiting cell wall synthesis. One of the resistance mechanisms against antimicrobial peptides is a detoxification module consisting of a two-component system and an ABC transporter. Upon the detection of such a compound, the two-component system induces the expression of the ABC transporter, which in turn removes the antibiotic from its site of action, mediating the resistance of the cell. Three such peptide antibiotic-sensing and detoxification modules are present in Bacillus subtilis. Here we show that each of these modules responds to a number of peptides and confers resistance against them. BceRS-BceAB (BceRS-AB) responds to bacitracin, plectasin, mersacidin, and actagardine. YxdJK-LM is induced by a cationic antimicrobial peptide, LL-37. The PsdRS-AB (formerly YvcPQ-RS) system responds primarily to lipid II-binding lantibiotics such as nisin and gallidermin. We characterized the psdRS-AB operon and defined the regulatory sequences within the P(psdA) promoter. Mutation analysis demonstrated that P(psdA) expression is fully PsdR dependent. The features of both the P(bceA) and P(psdA) promoters make them promising candidates as novel whole-cell biosensors that can easily be adjusted for high-throughput screening.
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