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Hoffmann A, Steffens U, Maček B, Franz-Wachtel M, Nieselt K, Harbig TA, Scherlach K, Hertweck C, Sahl HG, Bierbaum G. The unusual mode of action of the polyketide glycoside antibiotic cervimycin C. mSphere 2024; 9:e0076423. [PMID: 38722162 DOI: 10.1128/msphere.00764-23] [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: 01/02/2024] [Accepted: 03/28/2024] [Indexed: 05/30/2024] Open
Abstract
Cervimycins A-D are bis-glycosylated polyketide antibiotics produced by Streptomyces tendae HKI 0179 with bactericidal activity against Gram-positive bacteria. In this study, cervimycin C (CmC) treatment caused a spaghetti-like phenotype in Bacillus subtilis 168, with elongated curved cells, which stayed joined after cell division, and exhibited a chromosome segregation defect, resulting in ghost cells without DNA. Electron microscopy of CmC-treated Staphylococcus aureus (3 × MIC) revealed swollen cells, misshapen septa, cell wall thickening, and a rough cell wall surface. Incorporation tests in B. subtilis indicated an effect on DNA biosynthesis at high cervimycin concentrations. Indeed, artificial downregulation of the DNA gyrase subunit B gene (gyrB) increased the activity of cervimycin in agar diffusion tests, and, in high concentrations (starting at 62.5 × MIC), the antibiotic inhibited S. aureus DNA gyrase supercoiling activity in vitro. To obtain a more global view on the mode of action of CmC, transcriptomics and proteomics of cervimycin treated versus untreated S. aureus cells were performed. Interestingly, 3 × MIC of cervimycin did not induce characteristic responses, which would indicate disturbance of the DNA gyrase activity in vivo. Instead, cervimycin induced the expression of the CtsR/HrcA heat shock operon and the expression of autolysins, exhibiting similarity to the ribosome-targeting antibiotic gentamicin. In summary, we identified the DNA gyrase as a target, but at low concentrations, electron microscopy and omics data revealed a more complex mode of action of cervimycin, which comprised induction of the heat shock response, indicating protein stress in the cell.IMPORTANCEAntibiotic resistance of Gram-positive bacteria is an emerging problem in modern medicine, and new antibiotics with novel modes of action are urgently needed. Secondary metabolites from Streptomyces species are an important source of antibiotics, like the cervimycin complex produced by Streptomyces tendae HKI 0179. The phenotypic response of Bacillus subtilis and Staphylococcus aureus toward cervimycin C indicated a chromosome segregation and septum formation defect. This effect was at first attributed to an interaction between cervimycin C and the DNA gyrase. However, omics data of cervimycin treated versus untreated S. aureus cells indicated a different mode of action, because the stress response did not include the SOS response but resembled the response toward antibiotics that induce mistranslation or premature chain termination and cause protein stress. In summary, these results point toward a possibly novel mechanism that generates protein stress in the cells and subsequently leads to defects in cell and chromosome segregation.
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Affiliation(s)
- Alina Hoffmann
- University Hospital Bonn, Institute of Medical Microbiology, Immunology and Parasitology, Bonn, Germany
| | - Ursula Steffens
- University Hospital Bonn, Institute of Medical Microbiology, Immunology and Parasitology, Bonn, Germany
| | - Boris Maček
- University of Tübingen, Proteome Center Tübingen, Tübingen, Germany
| | | | - Kay Nieselt
- University of Tübingen, Interfaculty Institute for Bioinformatics and Medical Informatics, Tübingen, Germany
| | - Theresa Anisja Harbig
- University of Tübingen, Interfaculty Institute for Bioinformatics and Medical Informatics, Tübingen, Germany
| | - Kirstin Scherlach
- Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Jena, Germany
| | - Christian Hertweck
- Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Jena, Germany
- Friedrich Schiller University Jena, Institute of Microbiology, Faculty of Biological Sciences, Jena, Germany
| | - Hans-Georg Sahl
- University of Bonn, Institute for Pharmaceutical Microbiology, Bonn, Germany
| | - Gabriele Bierbaum
- University Hospital Bonn, Institute of Medical Microbiology, Immunology and Parasitology, Bonn, Germany
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Ahator SD, Hegstad K, Lentz CS, Johannessen M. Deciphering Staphylococcus aureus-host dynamics using dual activity-based protein profiling of ATP-interacting proteins. mSystems 2024; 9:e0017924. [PMID: 38656122 PMCID: PMC11097646 DOI: 10.1128/msystems.00179-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 03/26/2024] [Indexed: 04/26/2024] Open
Abstract
The utilization of ATP within cells plays a fundamental role in cellular processes that are essential for the regulation of host-pathogen dynamics and the subsequent immune response. This study focuses on ATP-binding proteins to dissect the complex interplay between Staphylococcus aureus and human cells, particularly macrophages (THP-1) and keratinocytes (HaCaT), during an intracellular infection. A snapshot of the various protein activity and function is provided using a desthiobiotin-ATP probe, which targets ATP-interacting proteins. In S. aureus, we observe enrichment in pathways required for nutrient acquisition, biosynthesis and metabolism of amino acids, and energy metabolism when located inside human cells. Additionally, the direct profiling of the protein activity revealed specific adaptations of S. aureus to the keratinocytes and macrophages. Mapping the differentially activated proteins to biochemical pathways in the human cells with intracellular bacteria revealed cell-type-specific adaptations to bacterial challenges where THP-1 cells prioritized immune defenses, autophagic cell death, and inflammation. In contrast, HaCaT cells emphasized barrier integrity and immune activation. We also observe bacterial modulation of host processes and metabolic shifts. These findings offer valuable insights into the dynamics of S. aureus-host cell interactions, shedding light on modulating host immune responses to S. aureus, which could involve developing immunomodulatory therapies. IMPORTANCE This study uses a chemoproteomic approach to target active ATP-interacting proteins and examines the dynamic proteomic interactions between Staphylococcus aureus and human cell lines THP-1 and HaCaT. It uncovers the distinct responses of macrophages and keratinocytes during bacterial infection. S. aureus demonstrated a tailored response to the intracellular environment of each cell type and adaptation during exposure to professional and non-professional phagocytes. It also highlights strategies employed by S. aureus to persist within host cells. This study offers significant insights into the human cell response to S. aureus infection, illuminating the complex proteomic shifts that underlie the defense mechanisms of macrophages and keratinocytes. Notably, the study underscores the nuanced interplay between the host's metabolic reprogramming and immune strategy, suggesting potential therapeutic targets for enhancing host defense and inhibiting bacterial survival. The findings enhance our understanding of host-pathogen interactions and can inform the development of targeted therapies against S. aureus infections.
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Affiliation(s)
- Stephen Dela Ahator
- Centre for New Antibacterial Strategies (CANS) & Research Group for Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT–The Arctic University of Norway, Tromsø, Norway
| | - Kristin Hegstad
- Centre for New Antibacterial Strategies (CANS) & Research Group for Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT–The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Christian S. Lentz
- Centre for New Antibacterial Strategies (CANS) & Research Group for Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT–The Arctic University of Norway, Tromsø, Norway
| | - Mona Johannessen
- Centre for New Antibacterial Strategies (CANS) & Research Group for Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT–The Arctic University of Norway, Tromsø, Norway
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Sharkey LKR, Guerillot R, Walsh CJ, Turner AM, Lee JYH, Neville SL, Klatt S, Baines SL, Pidot SJ, Rossello FJ, Seemann T, McWilliam HEG, Cho E, Carter GP, Howden BP, McDevitt CA, Hachani A, Stinear TP, Monk IR. The two-component system WalKR provides an essential link between cell wall homeostasis and DNA replication in Staphylococcus aureus. mBio 2023; 14:e0226223. [PMID: 37850732 PMCID: PMC10746227 DOI: 10.1128/mbio.02262-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 09/05/2023] [Indexed: 10/19/2023] Open
Abstract
Among the 16 two-component systems in the opportunistic human pathogen Staphylococcus aureus, only WalKR is essential. Like the orthologous systems in other Bacillota, S. aureus WalKR controls autolysins involved in peptidoglycan remodeling and is therefore intimately involved in cell division. However, despite the importance of WalKR in S. aureus, the basis for its essentiality is not understood and the regulon is poorly defined. Here, we defined a consensus WalR DNA-binding motif and the direct WalKR regulon by using functional genomics, including chromatin immunoprecipitation sequencing, with a panel of isogenic walKR mutants that had a spectrum of altered activities. Consistent with prior findings, the direct regulon includes multiple autolysin genes. However, this work also revealed that WalR directly regulates at least five essential genes involved in lipoteichoic acid synthesis (ltaS): translation (rplK), DNA compaction (hup), initiation of DNA replication (dnaA, hup) and purine nucleotide metabolism (prs). Thus, WalKR in S. aureus serves as a polyfunctional regulator that contributes to fundamental control over critical cell processes by coordinately linking cell wall homeostasis with purine biosynthesis, protein biosynthesis, and DNA replication. Our findings further address the essentiality of this locus and highlight the importance of WalKR as a bona fide target for novel anti-staphylococcal therapeutics. IMPORTANCE The opportunistic human pathogen Staphylococcus aureus uses an array of protein sensing systems called two-component systems (TCS) to sense environmental signals and adapt its physiology in response by regulating different genes. This sensory network is key to S. aureus versatility and success as a pathogen. Here, we reveal for the first time the full extent of the regulatory network of WalKR, the only staphylococcal TCS that is indispensable for survival under laboratory conditions. We found that WalKR is a master regulator of cell growth, coordinating the expression of genes from multiple, fundamental S. aureus cellular processes, including those involved in maintaining cell wall metabolism, protein biosynthesis, nucleotide metabolism, and the initiation of DNA replication.
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Affiliation(s)
- Liam K. R. Sharkey
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Romain Guerillot
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Calum J. Walsh
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Adrianna M. Turner
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Jean Y. H. Lee
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Stephanie L. Neville
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Stephan Klatt
- The Florey Institute of Neuroscience and Mental Health, Melbourne Dementia Research Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Sarah L. Baines
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Sacha J. Pidot
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Fernando J. Rossello
- University of Melbourne Centre for Cancer Research, The University of Melbourne, Melbourne, Victoria, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria, Australia
| | - Torsten Seemann
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology, Centre for Pathogen Genomics, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Hamish E. G. McWilliam
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Ellie Cho
- Biological Optical Microscopy Platform, University of Melbourne, Melbourne, Victoria, Australia
| | - Glen P. Carter
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Benjamin P. Howden
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology, Centre for Pathogen Genomics, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Christopher A. McDevitt
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Abderrahman Hachani
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology, Centre for Pathogen Genomics, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Ian R. Monk
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
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Gómez-Arrebola C, Hernandez SB, Culp EJ, Wright GD, Solano C, Cava F, Lasa I. Staphylococcus aureus susceptibility to complestatin and corbomycin depends on the VraSR two-component system. Microbiol Spectr 2023; 11:e0037023. [PMID: 37646518 PMCID: PMC10581084 DOI: 10.1128/spectrum.00370-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 06/30/2023] [Indexed: 09/01/2023] Open
Abstract
The overuse of antibiotics in humans and livestock has driven the emergence and spread of antimicrobial resistance and has therefore prompted research on the discovery of novel antibiotics. Complestatin (Cm) and corbomycin (Cb) are glycopeptide antibiotics with an unprecedented mechanism of action that is active even against methicillin-resistant and daptomycin-resistant Staphylococcus aureus. They bind to peptidoglycan and block the activity of peptidoglycan hydrolases required for remodeling the cell wall during growth. Bacterial signaling through two-component transduction systems (TCSs) has been associated with the development of S. aureus antimicrobial resistance. However, the role of TCSs in S. aureus susceptibility to Cm and Cb has not been previously addressed. In this study, we determined that, among all 16 S. aureus TCSs, VraSR is the only one controlling the susceptibility to Cm and Cb. Deletion of vraSR increased bacterial susceptibility to both antibiotics. Epistasis analysis with members of the vraSR regulon revealed that deletion of spdC, which encodes a membrane protein that scaffolds SagB for cleavage of peptidoglycan strands to achieve physiological length, in the vraSR mutant restored Cm and Cb susceptibility to wild-type levels. Moreover, deletion of either spdC or sagB in the wild-type strain increased resistance to both antibiotics. Further analyses revealed a significant rise in the relative amount of peptidoglycan and its total degree of cross-linkage in ΔspdC and ΔsagB mutants compared to the wild-type strain, suggesting that these changes in the cell wall provide resistance to the damaging effect of Cm and Cb. IMPORTANCE Although Staphylococcus aureus is a common colonizer of the skin and digestive tract of humans and many animals, it is also a versatile pathogen responsible for causing a wide variety and number of infections. Treatment of these infections requires the bacteria to be constantly exposed to antibiotic treatment, which facilitates the selection of antibiotic-resistant strains. The development of new antibiotics is, therefore, urgently needed. In this paper, we investigated the role of the sensory system of S. aureus in susceptibility to two new antibiotics: corbomycin and complestatin. The results shed light on the cell-wall synthesis processes that are affected by the presence of the antibiotic and the sensory system responsible for coordinating their activity.
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Affiliation(s)
- Carmen Gómez-Arrebola
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Sara B. Hernandez
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Elizabeth J. Culp
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Gerard D. Wright
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Cristina Solano
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Felipe Cava
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Iñigo Lasa
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
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5
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Schulz LM, Rothe P, Halbedel S, Gründling A, Rismondo J. Imbalance of peptidoglycan biosynthesis alters the cell surface charge of Listeria monocytogenes. Cell Surf 2022; 8:100085. [PMID: 36304571 PMCID: PMC9593813 DOI: 10.1016/j.tcsw.2022.100085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 02/09/2023] Open
Abstract
The bacterial cell wall is composed of a thick layer of peptidoglycan and cell wall polymers, which are either embedded in the membrane or linked to the peptidoglycan backbone and referred to as lipoteichoic acid (LTA) and wall teichoic acid (WTA), respectively. Modifications of the peptidoglycan or WTA backbone can alter the susceptibility of the bacterial cell towards cationic antimicrobials and lysozyme. The human pathogen Listeria monocytogenes is intrinsically resistant towards lysozyme, mainly due to deacetylation and O-acetylation of the peptidoglycan backbone via PgdA and OatA. Recent studies identified additional factors, which contribute to the lysozyme resistance of this pathogen. One of these is the predicted ABC transporter, EslABC. An eslB mutant is hyper-sensitive towards lysozyme, likely due to the production of thinner and less O-acetylated peptidoglycan. Using a suppressor screen, we show here that suppression of eslB phenotypes could be achieved by enhancing peptidoglycan biosynthesis, reducing peptidoglycan hydrolysis or alterations in WTA biosynthesis and modification. The lack of EslB also leads to a higher negative surface charge, which likely stimulates the activity of peptidoglycan hydrolases and lysozyme. Based on our results, we hypothesize that the portion of cell surface exposed WTA is increased in the eslB mutant due to the thinner peptidoglycan layer and that latter one could be caused by an impairment in UDP-N-acetylglucosamine (UDP-GlcNAc) production or distribution.
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Affiliation(s)
- Lisa Maria Schulz
- Department of General Microbiology, Institute of Microbiology and Genetics, GZMB, Georg-August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Patricia Rothe
- FG11, Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Burgstraße 37, 38855 Wernigerode, Germany
| | - Sven Halbedel
- FG11, Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Burgstraße 37, 38855 Wernigerode, Germany
- Institute for Medical Microbiology and Hospital Hygiene, Otto von Guericke University Magdeburg, Leipziger Straße 44, 39120 Magdeburg, Germany
| | - Angelika Gründling
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jeanine Rismondo
- Department of General Microbiology, Institute of Microbiology and Genetics, GZMB, Georg-August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
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Cervimycin-Resistant Staphylococcus aureus Strains Display Vancomycin-Intermediate Resistant Phenotypes. Microbiol Spectr 2022; 10:e0256722. [PMID: 36173303 PMCID: PMC9603734 DOI: 10.1128/spectrum.02567-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Resistance to antibiotics is an increasing problem and necessitates novel antibacterial therapies. The polyketide antibiotics cervimycin A to D are natural products of Streptomyces tendae HKI 0179 with promising activity against multidrug-resistant staphylococci and vancomycin-resistant enterococci. To initiate mode of action studies, we selected cervimycin C- and D-resistant (CmR) Staphylococcus aureus strains. Genome sequencing of CmR mutants revealed amino acid exchanges in the essential histidine kinase WalK, the Clp protease proteolytic subunit ClpP or the Clp ATPase ClpC, and the heat shock protein DnaK. Interestingly, all characterized CmR mutants harbored a combination of mutations in walK and clpP or clpC. In vitro and in vivo analyses showed that the mutations in the Clp proteins abolished ClpP or ClpC activity, and the deletion of clpP rendered S. aureus but not all Bacillus subtilis strains cervimycin-resistant. The essential gene walK was the second mutational hotspot in the CmR S. aureus strains, which decreased WalK activity in vitro and generated a vancomycin-intermediate resistant phenotype, with a thickened cell wall, a lower growth rate, and reduced cell lysis. Transcriptomic and proteomic analyses revealed massive alterations in the CmR strains compared to the parent strain S. aureus SG511, with major shifts in the heat shock regulon, the metal ion homeostasis, and the carbohydrate metabolism. Taken together, mutations in the heat shock genes clpP, clpC, and dnaK, and the walK kinase gene in CmR mutants induced a vancomycin-intermediate resistant phenotype in S. aureus, suggesting cell wall metabolism or the Clp protease system as primary target of cervimycin. IMPORTANCE Staphylococcus aureus is a frequent cause of infections in both the community and hospital setting. Resistance development of S. aureus to various antibiotics is a severe problem for the treatment of this pathogen worldwide. New powerful antimicrobial agents against Gram-positives are needed, since antibiotics like vancomycin fail to cure vancomycin-intermediate resistant S. aureus (VISA) and vancomycin-resistant enterococci (VRE) infections. One candidate substance with promising activity against these organisms is cervimycin, which is an antibiotic complex with a yet unknown mode of action. In our study, we provide first insights into the mode of action of cervimycins. By characterizing cervimycin-resistant S. aureus strains, we revealed the Clp system and the essential kinase WalK as mutational hotspots for cervimycin resistance in S. aureus. It further emerged that cervimycin-resistant S. aureus strains show a VISA phenotype, indicating a role of cervimycin in perturbing the bacterial cell envelope.
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Sionov RV, Banerjee S, Bogomolov S, Smoum R, Mechoulam R, Steinberg D. Targeting the Achilles’ Heel of Multidrug-Resistant Staphylococcus aureus by the Endocannabinoid Anandamide. Int J Mol Sci 2022; 23:ijms23147798. [PMID: 35887146 PMCID: PMC9319909 DOI: 10.3390/ijms23147798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 02/06/2023] Open
Abstract
Antibiotic-resistant Staphylococcus aureus is a major health issue that requires new therapeutic approaches. Accumulating data suggest that it is possible to sensitize these bacteria to antibiotics by combining them with inhibitors targeting efflux pumps, the low-affinity penicillin-binding protein PBP2a, cell wall teichoic acid, or the cell division protein FtsZ. We have previously shown that the endocannabinoid Anandamide (N-arachidonoylethanolamine; AEA) could sensitize drug-resistant S. aureus to a variety of antibiotics, among others, through growth arrest and inhibition of drug efflux. Here, we looked at biochemical alterations caused by AEA. We observed that AEA increased the intracellular drug concentration of a fluorescent penicillin and augmented its binding to membrane proteins with concomitant altered membrane distribution of these proteins. AEA also prevented the secretion of exopolysaccharides (EPS) and reduced the cell wall teichoic acid content, both processes known to require transporter proteins. Notably, AEA was found to inhibit membrane ATPase activity that is necessary for transmembrane transport. AEA did not affect the membrane GTPase activity, and the GTPase cell division protein FtsZ formed the Z-ring of the divisome normally in the presence of AEA. Rather, AEA caused a reduction in murein hydrolase activities involved in daughter cell separation. Altogether, this study shows that AEA affects several biochemical processes that culminate in the sensitization of the drug-resistant bacteria to antibiotics.
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Affiliation(s)
- Ronit Vogt Sionov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
- Correspondence:
| | - Shreya Banerjee
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Sergei Bogomolov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Reem Smoum
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Raphael Mechoulam
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Doron Steinberg
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
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8
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Chen H, Yu C, Wu H, Li G, Li C, Hong W, Yang X, Wang H, You X. Recent Advances in Histidine Kinase-Targeted Antimicrobial Agents. Front Chem 2022; 10:866392. [PMID: 35860627 PMCID: PMC9289397 DOI: 10.3389/fchem.2022.866392] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/16/2022] [Indexed: 11/15/2022] Open
Abstract
The prevalence of antimicrobial-resistant pathogens significantly limited the number of effective antibiotics available clinically, which urgently requires new drug targets to screen, design, and develop novel antibacterial drugs. Two-component system (TCS), which is comprised of a histidine kinase (HK) and a response regulator (RR), is a common mechanism whereby bacteria can sense a range of stimuli and make an appropriate adaptive response. HKs as the sensor part of the bacterial TCS can regulate various processes such as growth, vitality, antibiotic resistance, and virulence, and have been considered as a promising target for antibacterial drugs. In the current review, we highlighted the structural basis and functional importance of bacterial TCS especially HKs as a target in the discovery of new antimicrobials, and summarize the latest research progress of small-molecule HK-inhibitors as potential novel antimicrobial drugs reported in the past decade.
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Affiliation(s)
- Hongtong Chen
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chengqi Yu
- School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Han Wu
- School of Pharmacy, Minzu University of China, Beijing, China
- Key Laboratory of Ethnomedicine (Minzu University of China), Ministry of Education, Beijing, China
| | - Guoqing Li
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Congran Li
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wei Hong
- Beijing Institute of Collaborative Innovation, Beijing, China
| | - Xinyi Yang
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- *Correspondence: Xinyi Yang, ; Hao Wang, ; Xuefu You,
| | - Hao Wang
- School of Pharmacy, Minzu University of China, Beijing, China
- Key Laboratory of Ethnomedicine (Minzu University of China), Ministry of Education, Beijing, China
- Institute of National Security, Minzu University of China, Beijing, China
- *Correspondence: Xinyi Yang, ; Hao Wang, ; Xuefu You,
| | - Xuefu You
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- *Correspondence: Xinyi Yang, ; Hao Wang, ; Xuefu You,
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9
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Wang M, Buist G, van Dijl JM. Staphylococcus aureus cell wall maintenance - the multifaceted roles of peptidoglycan hydrolases in bacterial growth, fitness, and virulence. FEMS Microbiol Rev 2022; 46:6604383. [PMID: 35675307 PMCID: PMC9616470 DOI: 10.1093/femsre/fuac025] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/22/2022] [Accepted: 05/25/2022] [Indexed: 01/07/2023] Open
Abstract
Staphylococcus aureus is an important human and livestock pathogen that is well-protected against environmental insults by a thick cell wall. Accordingly, the wall is a major target of present-day antimicrobial therapy. Unfortunately, S. aureus has mastered the art of antimicrobial resistance, as underscored by the global spread of methicillin-resistant S. aureus (MRSA). The major cell wall component is peptidoglycan. Importantly, the peptidoglycan network is not only vital for cell wall function, but it also represents a bacterial Achilles' heel. In particular, this network is continuously opened by no less than 18 different peptidoglycan hydrolases (PGHs) encoded by the S. aureus core genome, which facilitate bacterial growth and division. This focuses attention on the specific functions executed by these enzymes, their subcellular localization, their control at the transcriptional and post-transcriptional levels, their contributions to staphylococcal virulence and their overall importance in bacterial homeostasis. As highlighted in the present review, our understanding of the different aspects of PGH function in S. aureus has been substantially increased over recent years. This is important because it opens up new possibilities to exploit PGHs as innovative targets for next-generation antimicrobials, passive or active immunization strategies, or even to engineer them into effective antimicrobial agents.
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Affiliation(s)
- Min Wang
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | | | - Jan Maarten van Dijl
- Corresponding author: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, HPC EB80, 9700 RB Groningen, the Netherlands, Tel. +31-50-3615187; Fax. +31-50-3619105; E-mail:
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10
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Luo S, Yang X, Wu S, Li Y, Wu J, Liu M, Liu Z, Yu K, Wang X, Dai T, Huang X, Hu X. Understanding a defensive response of methicillin-resistant Staphylococcus aureus (MRSA) after exposure to multiple cycles of sub-lethal blue Light. FEMS Microbiol Lett 2022; 369:6604381. [PMID: 35675215 DOI: 10.1093/femsle/fnac050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/04/2022] [Accepted: 06/03/2022] [Indexed: 11/14/2022] Open
Abstract
Blue light (BL) has showed bactericidal effectiveness against methicillin-resistant Staphylococcus aureus (MRSA), one of the major clinical pathogens with antibiotic resistance. Bacteria likely respond to the oxidative stress induced by BL, however, the defensive response is still unclear. This study was to reveal the phenotypic change of MRSA after exposed to 15 cycles of sub-lethal blue light illumination. The comparative transcriptomic results showed that the expression of peptidoglycan (PG) synthesis gene glmS was significantly up-regulated in the cells after the multiple cycle light treatment, and the biochemical analysis determined that the content of PG synthesized was increased by 25.86% when compared to that in control cells. Furthermore, significant thickening of the cell wall was observed under transmission electron microscope (P < 0.05). The light sensitivity of the tested MRSA strain was reduced after the multiple cycles light treatment, indicating the possibility of MRSA being more adaptive to the BL stress. The present study suggested that the multiple cycles of sub-lethal BL could change the light susceptibility of MRSA through thickening cell wall.
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Affiliation(s)
- Shuanghua Luo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xi Yang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Shuyan Wu
- AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand
| | - Yuanbu Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Jiaxin Wu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Minmin Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Zhaojun Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Keyang Yu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Tianhong Dai
- Department of Dermatology, Harvard Medical School, Boston, MA 02114, USA
| | - Xiaodong Huang
- Guangzhou YueHui Cosmetics Co. Ltd., Guangzhou 514410, China
| | - Xiaoqing Hu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
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11
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The WalRK Two-Component System Is Essential for Proper Cell Envelope Biogenesis in Clostridioides difficile. J Bacteriol 2022; 204:e0012122. [PMID: 35575581 PMCID: PMC9210968 DOI: 10.1128/jb.00121-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The WalR-WalK two-component regulatory system (TCS) is found in all Firmicutes, in which it regulates the expression of multiple genes required for remodeling the cell envelope during growth and division. Unlike most TCSs, WalRK is essential for viability, so it has attracted interest as a potential antibiotic target. In this study, we used overexpression of WalR and CRISPR interference to investigate the Wal system of Clostridioides difficile, a major cause of hospital-associated diarrhea in high-income countries. We confirmed that the wal operon is essential and identified morphological defects and cell lysis as the major terminal phenotypes of altered wal expression. We also used transcriptome sequencing (RNA-seq) to identify over 150 genes whose expression changes in response to WalR levels. This gene set is enriched in cell envelope genes and includes genes encoding several predicted PG hydrolases and proteins that could regulate PG hydrolase activity. A distinct feature of the C. difficile cell envelope is the presence of an S-layer, and we found that WalR affects expression of several genes which encode S-layer proteins. An unexpected finding was that some Wal-associated phenotypic defects were inverted in comparison to what has been reported for other Firmicutes. For example, downregulation of Wal signaling caused C. difficile cells to become longer rather than shorter, as in Bacillus subtilis. Likewise, downregulation of Wal rendered C. difficile more sensitive to vancomycin, whereas reduced Wal activity is linked to increased vancomycin resistance in Staphylococcus aureus. IMPORTANCE The WalRK two-component system (TCS) is essential for coordinating synthesis and turnover of peptidoglycan in Firmicutes. We investigated the WalRK TCS in Clostridioides difficile, an important bacterial pathogen with an atypical cell envelope. We confirmed that WalRK is essential and regulates cell envelope biogenesis, although several of the phenotypic changes we observed were opposite to what has been reported for other Firmicutes. We also identified over 150 genes whose expression is controlled either directly or indirectly by WalR. Overall, our findings provide a foundation for future investigations of an important regulatory system and potential antibiotic target in C. difficile.
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12
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Kong L, Su M, Sang J, Huang S, Wang M, Cai Y, Xie M, Wu J, Wang S, Foster SJ, Zhang J, Han A. The W-Acidic Motif of Histidine Kinase WalK Is Required for Signaling and Transcriptional Regulation in Streptococcus mutans. Front Microbiol 2022; 13:820089. [PMID: 35558126 PMCID: PMC9087282 DOI: 10.3389/fmicb.2022.820089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/14/2022] [Indexed: 02/05/2023] Open
Abstract
In Streptococcus mutans, we find that the histidine kinase WalK possesses the longest C-terminal tail (CTT) among all 14 TCSs, and this tail plays a key role in the interaction of WalK with its response regulator WalR. We demonstrate that the intrinsically disordered CTT is characterized by a conserved tryptophan residue surrounded by acidic amino acids. Mutation in the tryptophan not only disrupts the stable interaction, but also impairs the efficient phosphotransferase and phosphatase activities of WalRK. In addition, the tryptophan is important for WalK to compete with DNA containing a WalR binding motif for the WalR interaction. We further show that the tryptophan is important for in vivo transcriptional regulation and bacterial biofilm formation by S. mutans. Moreover, Staphylococcus aureus WalK also has a characteristic CTT, albeit relatively shorter, with a conserved W-acidic motif, that is required for the WalRK interaction in vitro. Together, these data reveal that the W-acidic motif of WalK is indispensable for its interaction with WalR, thereby playing a key role in the WalRK-dependent signal transduction, transcriptional regulation and biofilm formation.
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Affiliation(s)
- Lingyuan Kong
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Mingyang Su
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Jiayan Sang
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Shanshan Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Min Wang
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Yongfei Cai
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Mingquan Xie
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Jun Wu
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Shida Wang
- State Key Laboratory for Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Simon J Foster
- Department of Molecular Biology and Biotechnology, The Florey Institute, The University of Sheffield, Sheffield, United Kingdom
| | - Jiaqin Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Aidong Han
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
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13
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Wu S, Zhang J, Peng Q, Liu Y, Lei L, Zhang H. The Role of Staphylococcus aureus YycFG in Gene Regulation, Biofilm Organization and Drug Resistance. Antibiotics (Basel) 2021; 10:antibiotics10121555. [PMID: 34943766 PMCID: PMC8698359 DOI: 10.3390/antibiotics10121555] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/09/2021] [Accepted: 12/16/2021] [Indexed: 02/05/2023] Open
Abstract
Antibiotic resistance is a serious global health concern that may have significant social and financial consequences. Methicillin-resistant Staphylococcus aureus (MRSA) infection is responsible for substantial morbidity and leads to the death of 21.8% of infected patients annually. A lack of novel antibiotics has prompted the exploration of therapies targeting bacterial virulence mechanisms. The two-component signal transduction system (TCS) enables microbial cells to regulate gene expression and the subsequent metabolic processes that occur due to environmental changes. The YycFG TCS in S. aureus is essential for bacterial viability, the regulation of cell membrane metabolism, cell wall synthesis and biofilm formation. However, the role of YycFG-associated biofilm organization in S. aureus antimicrobial drug resistance and gene regulation has not been discussed in detail. We reviewed the main molecules involved in YycFG-associated cell wall biosynthesis, biofilm development and polysaccharide intercellular adhesin (PIA) accumulation. Two YycFG-associated regulatory mechanisms, accessory gene regulator (agr) and staphylococcal accessory regulator (SarA), were also discussed. We highlighted the importance of biofilm formation in the development of antimicrobial drug resistance in S. aureus infections. Data revealed that inhibition of the YycFG pathway reduced PIA production, biofilm formation and bacterial pathogenicity, which provides a potential target for the management of MRSA-induced infections.
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Affiliation(s)
- Shizhou Wu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu 610041, China; (S.W.); (J.Z.); (Q.P.)
| | - Junqi Zhang
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu 610041, China; (S.W.); (J.Z.); (Q.P.)
| | - Qi Peng
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu 610041, China; (S.W.); (J.Z.); (Q.P.)
| | - Yunjie Liu
- West China School of Public Health, Sichuan University, Chengdu 610041, China;
| | - Lei Lei
- West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
- Correspondence: (L.L.); (H.Z.)
| | - Hui Zhang
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu 610041, China; (S.W.); (J.Z.); (Q.P.)
- Correspondence: (L.L.); (H.Z.)
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14
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Kant S, Pancholi V. Novel Tyrosine Kinase-Mediated Phosphorylation With Dual Specificity Plays a Key Role in the Modulation of Streptococcus pyogenes Physiology and Virulence. Front Microbiol 2021; 12:689246. [PMID: 34950110 PMCID: PMC8689070 DOI: 10.3389/fmicb.2021.689246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/25/2021] [Indexed: 11/15/2022] Open
Abstract
Streptococcus pyogenes (Group A Streptococcus, GAS) genomes do not contain a gene encoding a typical bacterial-type tyrosine kinase (BY-kinase) but contain an orphan gene-encoding protein Tyr-phosphatase (SP-PTP). Hence, the importance of Tyr-phosphorylation is underappreciated and not recognized for its role in GAS pathophysiology and pathogenesis. The fact that SP-PTP dephosphorylates Abl-tyrosine kinase-phosphorylated myelin basic protein (MBP), and SP-STK (S. pyogenes Ser/Thr kinase) also autophosphorylates its Tyr101-residue prompted us to identify a putative tyrosine kinase and Tyr-phosphorylation in GAS. Upon a genome-wide search of kinases possessing a classical Walker motif, we identified a non-canonical tyrosine kinase M5005_Spy_1476, a ∼17 kDa protein (153 aa) (SP-TyK). The purified recombinant SP-TyK autophosphorylated in the presence of ATP. In vitro and in vivo phosphoproteomic analyses revealed two key phosphorylated tyrosine residues located within the catalytic domain of SP-TyK. An isogenic mutant lacking SP-TyK derived from the M1T1 strain showed a retarded growth pattern. It displayed defective cell division and long chains with multiple parallel septa, often resulting in aggregates. Transcriptomic analysis of the mutant revealed 287 differentially expressed genes responsible for GAS pathophysiology and pathogenesis. SP-TyK also phosphorylated GAS CovR, WalR, SP-STP, and SDH/GAPDH proteins with dual specificity targeting their Tyr/Ser/Thr residues as revealed by biochemical and mass-spectrometric-based phosphoproteomic analyses. SP-TyK-phosphorylated CovR bound to PcovR efficiently. The mutant displayed sustained release of IL-6 compared to TNF-α during co-culturing with A549 lung cell lines, attenuation in mice sepsis model, and significantly reduced ability to adhere to and invade A549 lung cells and form biofilms on abiotic surfaces. SP-TyK, thus, plays a critical role in fine-tuning the regulation of key cellular functions essential for GAS pathophysiology and pathogenesis through post-translational modifications and hence, may serve as a promising target for future therapeutic developments.
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15
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Demonstration of the role of cell wall homeostasis in Staphylococcus aureus growth and the action of bactericidal antibiotics. Proc Natl Acad Sci U S A 2021; 118:2106022118. [PMID: 34716264 PMCID: PMC8612353 DOI: 10.1073/pnas.2106022118] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 09/02/2021] [Indexed: 12/29/2022] Open
Abstract
Bacterial cell wall peptidoglycan is essential, maintaining both cellular integrity and morphology, in the face of internal turgor pressure. Peptidoglycan synthesis is important, as it is targeted by cell wall antibiotics, including methicillin and vancomycin. Here, we have used the major human pathogen Staphylococcus aureus to elucidate both the cell wall dynamic processes essential for growth (life) and the bactericidal effects of cell wall antibiotics (death) based on the principle of coordinated peptidoglycan synthesis and hydrolysis. The death of S. aureus due to depletion of the essential, two-component and positive regulatory system for peptidoglycan hydrolase activity (WalKR) is prevented by addition of otherwise bactericidal cell wall antibiotics, resulting in stasis. In contrast, cell wall antibiotics kill via the activity of peptidoglycan hydrolases in the absence of concomitant synthesis. Both methicillin and vancomycin treatment lead to the appearance of perforating holes throughout the cell wall due to peptidoglycan hydrolases. Methicillin alone also results in plasmolysis and misshapen septa with the involvement of the major peptidoglycan hydrolase Atl, a process that is inhibited by vancomycin. The bactericidal effect of vancomycin involves the peptidoglycan hydrolase SagB. In the presence of cell wall antibiotics, the inhibition of peptidoglycan hydrolase activity using the inhibitor complestatin results in reduced killing, while, conversely, the deregulation of hydrolase activity via loss of wall teichoic acids increases the death rate. For S. aureus, the independent regulation of cell wall synthesis and hydrolysis can lead to cell growth, death, or stasis, with implications for the development of new control regimes for this important pathogen.
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16
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Five major two components systems of Staphylococcus aureus for adaptation in diverse hostile environment. Microb Pathog 2021; 159:105119. [PMID: 34339796 DOI: 10.1016/j.micpath.2021.105119] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 05/21/2021] [Accepted: 07/28/2021] [Indexed: 11/21/2022]
Abstract
Staphylococcus aureus is an eminent and opportunistic human pathogen that can colonize in the intestines, skin tissue and perineal regions of the host and cause severe infectious diseases. The presence of complex regulatory network and existence of virulent gene expression along with tuning metabolism enables the S. aureus to adopt the diversity of environments. Two component system (TCS) is a widely distributed mechanism in S. aureus that permit it for changing gene expression profile in response of environment stimuli. TCS usually consist of transmembrane histidine kinase (HK) and cytosolic response regulator. S. aureus contains totally 16 conserved pairs of two component systems, involving in different signaling mechanisms. There is a connection among these regulatory circuits and they can easily have effect on each other's expression. This review has discussed five major types of TCS in S. aureus and covers the recent knowledge of their virulence gene expression. We can get more understanding towards staphylococcal pathogenicity by getting insights about gene regulatory pathways via TCS, which can further provide implications in vaccine formation and new ways for drug design to combat serious infections caused by S. aureus in humans.
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17
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Fisher JF, Mobashery S. β-Lactams against the Fortress of the Gram-Positive Staphylococcus aureus Bacterium. Chem Rev 2021; 121:3412-3463. [PMID: 33373523 PMCID: PMC8653850 DOI: 10.1021/acs.chemrev.0c01010] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The biological diversity of the unicellular bacteria-whether assessed by shape, food, metabolism, or ecological niche-surely rivals (if not exceeds) that of the multicellular eukaryotes. The relationship between bacteria whose ecological niche is the eukaryote, and the eukaryote, is often symbiosis or stasis. Some bacteria, however, seek advantage in this relationship. One of the most successful-to the disadvantage of the eukaryote-is the small (less than 1 μm diameter) and nearly spherical Staphylococcus aureus bacterium. For decades, successful clinical control of its infection has been accomplished using β-lactam antibiotics such as the penicillins and the cephalosporins. Over these same decades S. aureus has perfected resistance mechanisms against these antibiotics, which are then countered by new generations of β-lactam structure. This review addresses the current breadth of biochemical and microbiological efforts to preserve the future of the β-lactam antibiotics through a better understanding of how S. aureus protects the enzyme targets of the β-lactams, the penicillin-binding proteins. The penicillin-binding proteins are essential enzyme catalysts for the biosynthesis of the cell wall, and understanding how this cell wall is integrated into the protective cell envelope of the bacterium may identify new antibacterials and new adjuvants that preserve the efficacy of the β-lactams.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
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18
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Mikkelsen K, Sirisarn W, Alharbi O, Alharbi M, Liu H, Nøhr-Meldgaard K, Mayer K, Vestergaard M, Gallagher LA, Derrick JP, McBain AJ, Biboy J, Vollmer W, O'Gara JP, Grunert T, Ingmer H, Xia G. The Novel Membrane-Associated Auxiliary Factors AuxA and AuxB Modulate β-lactam Resistance in MRSA by stabilizing Lipoteichoic Acids. Int J Antimicrob Agents 2021; 57:106283. [PMID: 33503451 DOI: 10.1016/j.ijantimicag.2021.106283] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/08/2020] [Accepted: 12/19/2020] [Indexed: 01/20/2023]
Abstract
A major determinant of β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is the drug insensitive transpeptidase, PBP2a, encoded by mecA. Full expression of the resistance phenotype requires auxiliary factors. Two such factors, auxiliary factor A (auxA, SAUSA300_0980) and B (auxB, SAUSA300_1003), were identified in a screen against mutants with increased susceptibility to β-lactams in the MRSA strain, JE2. auxA and auxB encode transmembrane proteins, with AuxA predicted to be a transporter. Inactivation of auxA or auxB enhanced β-lactam susceptibility in community-, hospital- and livestock-associated MRSA strains without affecting PBP2a expression, peptidoglycan cross-linking or wall teichoic acid synthesis. Both mutants displayed increased susceptibility to inhibitors of lipoteichoic acid (LTA) synthesis and alanylation pathways and released LTA even in the absence of β-lactams. The β-lactam susceptibility of the aux mutants was suppressed by mutations inactivating gdpP, which was previously found to allow growth of mutants lacking the lipoteichoic synthase enzyme, LtaS. Using the Galleria mellonella infection model, enhanced survival of larvae inoculated with either auxA or auxB mutants was observed compared with the wild-type strain following treatment with amoxicillin. These results indicate that AuxA and AuxB are central for LTA stability and potential inhibitors can be tools to re-sensitize MRSA strains to β-lactams and combat MRSA infections.
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Affiliation(s)
- Kasper Mikkelsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark
| | - Wanchat Sirisarn
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Ohood Alharbi
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Mohanned Alharbi
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Huayong Liu
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | | | - Katharina Mayer
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Martin Vestergaard
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark
| | - Laura A Gallagher
- Department of Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Jeremy P Derrick
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Andrew J McBain
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, NU Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, NU Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - James P O'Gara
- Department of Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Tom Grunert
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark.
| | - Guoqing Xia
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom.
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19
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Grossman AB, Rice KC, Vermerris W. Lignin solvated in zwitterionic Good's buffers displays antibacterial synergy against
Staphylococcus aureus
. J Appl Polym Sci 2020. [DOI: 10.1002/app.49107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Adam B. Grossman
- Department of Microbiology & Cell Science IFAS, University of Florida Gainesville Florida, USA
| | - Kelly C. Rice
- Department of Microbiology & Cell Science IFAS, University of Florida Gainesville Florida, USA
| | - Wilfred Vermerris
- Department of Microbiology & Cell Science IFAS, University of Florida Gainesville Florida, USA
- UF Genetics Institute, University of Florida Gainesville Florida
- Florida Center for Renewable Chemicals and Fuels University of Florida Gainesville Florida
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20
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Another Breaker of the Wall: the Biological Function of the Usp45 Protein of Lactococcus lactis. Appl Environ Microbiol 2020; 86:AEM.00903-20. [PMID: 32532874 DOI: 10.1128/aem.00903-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 06/01/2020] [Indexed: 11/20/2022] Open
Abstract
Lactococcus lactis is a Gram-positive bacterium that is widely used as a cell factory for the expression of heterologous proteins that are relevant in the pharmaceutical and nutraceutical fields. The signal peptide of the major secreted protein of L. lactis, Usp45, has been employed extensively in engineering strategies to secrete proteins of interest. However, the biological function of Usp45 has remained obscure despite more than 25 years of research. Studies on Usp45 homologs in other Gram-positive bacteria suggest that Usp45 may play a role in cell wall turnover processes. Here, we show the effect of inactivation and overexpression of the usp45 gene on L. lactis growth, phenotype, and cell division. Our results are in agreement with those obtained in streptococci and demonstrate that the L. lactis Usp45 protein is essential for proper cell division. We also show that the usp45 promoter is highly activated by galactose. Overall, our results indicate that Usp45 mediates cell separation, probably by acting as a peptidoglycan hydrolase.IMPORTANCE The cell wall, composed mainly of peptidoglycan, is key to maintaining the cell shape and protecting the cell from bursting. Peptidoglycan degradation by peptidoglycan hydrolysis and autolysins occurs during growth and cell division. Since peptidoglycan hydrolases are important for virulence, envelope integrity, and regulation of cell division, it is valuable to investigate their function and regulation. Notably, PcsB-like proteins such as Usp45 have been proposed as new targets for antimicrobial drugs and could also be target for the development of food-grade suicide systems. In addition, although various other expression and secretion systems have been developed for use in Lactococcus lactis, the most-used signal peptide for protein secretion in this bacterium is that of the Usp45 protein. Thus, elucidating the biological function of Usp45 and determining the factors affecting its expression would contribute to optimize several applications.
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21
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Gajdiss M, Monk IR, Bertsche U, Kienemund J, Funk T, Dietrich A, Hort M, Sib E, Stinear TP, Bierbaum G. YycH and YycI Regulate Expression of Staphylococcus aureus Autolysins by Activation of WalRK Phosphorylation. Microorganisms 2020; 8:microorganisms8060870. [PMID: 32526915 PMCID: PMC7355866 DOI: 10.3390/microorganisms8060870] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/05/2020] [Accepted: 06/07/2020] [Indexed: 11/16/2022] Open
Abstract
Staphylococcus aureus is a facultative pathogen that can encode numerous antibiotic resistance and immune evasion genes and can cause severe infections. Reduced susceptibility to last resort antibiotics such as vancomycin and daptomycin is often associated with mutations in walRK, an essential two-component regulatory system (TCS). This study focuses on the WalK accessory membrane proteins YycH and YycI and their influence on WalRK phosphorylation. Depletion of YycH and YycI by antisense RNA caused an impaired autolysis, indicating a positive regulatory function on WalK as has been previously described. Phosphorylation assays with full-length recombinant proteins in phospholipid liposomes showed that YycH and YycI stimulate WalK activity and that both regulatory proteins are needed for full activation of the WalK kinase. This was validated in vivo through examining the phosphorylation status of WalR using Phos-tag SDS-PAGE with a yycHI deletion mutant exhibiting reduced levels of phosphorylated WalR. In the yycHI knockdown strain, muropeptide composition of the cell wall was not affected, however, the wall teichoic acid content was increased. In conclusion, a direct modulation of WalRK phosphorylation activity by the accessory proteins YycH and YycI is reported both in vitro and in vivo. Taken together, our results show that YycH and YycI are important in the direct regulation of WalRK-dependent cell wall metabolism.
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Affiliation(s)
- Mike Gajdiss
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Ian R. Monk
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3010, Australia; (I.R.M.); (T.P.S.)
| | - Ute Bertsche
- Department of Infection Biology, University of Tuebingen, 72076 Tuebingen, Germany;
| | - Janina Kienemund
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Tanja Funk
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Alina Dietrich
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Michael Hort
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Esther Sib
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3010, Australia; (I.R.M.); (T.P.S.)
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
- Correspondence:
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22
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Cannabidiol is an effective helper compound in combination with bacitracin to kill Gram-positive bacteria. Sci Rep 2020; 10:4112. [PMID: 32139776 PMCID: PMC7057955 DOI: 10.1038/s41598-020-60952-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/19/2020] [Indexed: 01/19/2023] Open
Abstract
The cannabinoid cannabidiol (CBD) is characterised in this study as a helper compound against resistant bacteria. CBD potentiates the effect of bacitracin (BAC) against Gram-positive bacteria (Staphylococcus species, Listeria monocytogenes, and Enterococcus faecalis) but appears ineffective against Gram-negative bacteria. CBD reduced the MIC value of BAC by at least 64-fold and the combination yielded an FIC index of 0.5 or below in most Gram-positive bacteria tested. Morphological changes in S. aureus as a result of the combination of CBD and BAC included several septa formations during cell division along with membrane irregularities. Analysis of the muropeptide composition of treated S. aureus indicated no changes in the cell wall composition. However, CBD and BAC treated bacteria did show a decreased rate of autolysis. The bacteria further showed a decreased membrane potential upon treatment with CBD; yet, they did not show any further decrease upon combination treatment. Noticeably, expression of a major cell division regulator gene, ezrA, was reduced two-fold upon combination treatment emphasising the impact of the combination on cell division. Based on these observations, the combination of CBD and BAC is suggested to be a putative novel treatment in clinical settings for treatment of infections with antibiotic resistant Gram-positive bacteria.
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23
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Scornec H, Palud A, Pédron T, Wheeler R, Petitgonnet C, Boneca IG, Cavin JF, Sansonetti PJ, Licandro H. Study of the cwaRS-ldcA Operon Coding a Two-Component System and a Putative L,D-Carboxypeptidase in Lactobacillus paracasei. Front Microbiol 2020; 11:156. [PMID: 32194510 PMCID: PMC7062640 DOI: 10.3389/fmicb.2020.00156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/22/2020] [Indexed: 11/22/2022] Open
Abstract
The cell surface is the primary recognition site between the bacterium and the host. An operon of three genes, LSEI_0219 (cwaR), LSEI_0220 (cwaS), and LSEI_0221 (ldcA), has been previously identified as required for the establishment of Lactobacillus paracasei in the gut. The genes cwaR and cwaS encode a predicted two-component system (TCS) and ldcA a predicted D-alanyl-D-alanine carboxypeptidase which is a peptidoglycan (PG) biosynthesis enzyme. We explored the functionality and the physiological role of these three genes, particularly their impact on the bacterial cell wall architecture and on the bacterial adaptation to environmental perturbations in the gut. The functionality of CwaS/R proteins as a TCS has been demonstrated by biochemical analysis. It is involved in the transcriptional regulation of several genes of the PG biosynthesis. Analysis of the muropeptides of PG in mutants allowed us to re-annotate LSEI_0221 as a putative L,D-carboxypeptidase (LdcA). The absence of this protein coincided with a decrease of two surface antigens: LSEI_0020, corresponding to p40 or msp2 whose implication in the host epithelial homeostasis has been recently studied, and LSEI_2029 which has never been functionally characterized. The inactivation of each of these three genes induces susceptibility to antimicrobial peptides (hBD1, hBD2, and CCL20), which could be the main cause of the gut establishment deficiency. Thus, this operon is necessary for the presence of two surface antigens and for a suitable cell wall architecture.
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Affiliation(s)
- Hélène Scornec
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | - Aurore Palud
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | - Thierry Pédron
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- Unité INSERM, Institut Pasteur, Paris, France
| | - Richard Wheeler
- Unité de Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur, Paris, France
- Avenir Group, INSERM, Paris, France
| | - Clément Petitgonnet
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | - Ivo Gomperts Boneca
- Unité de Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur, Paris, France
- Avenir Group, INSERM, Paris, France
| | - Jean-François Cavin
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | - Philippe J. Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- Unité INSERM, Institut Pasteur, Paris, France
- Chaire de Microbiologie et Maladies Infectieuses, Collège de France, Paris, France
| | - Hélène Licandro
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
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24
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Dobihal GS, Brunet YR, Flores-Kim J, Rudner DZ. Homeostatic control of cell wall hydrolysis by the WalRK two-component signaling pathway in Bacillus subtilis. eLife 2019; 8:52088. [PMID: 31808740 PMCID: PMC7299342 DOI: 10.7554/elife.52088] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 12/05/2019] [Indexed: 12/31/2022] Open
Abstract
Bacterial cells are encased in a peptidoglycan (PG) exoskeleton that protects them from osmotic lysis and specifies their distinct shapes. Cell wall hydrolases are required to enlarge this covalently closed macromolecule during growth, but how these autolytic enzymes are regulated remains poorly understood. Bacillus subtilis encodes two functionally redundant D,L-endopeptidases (CwlO and LytE) that cleave peptide crosslinks to allow expansion of the PG meshwork during growth. Here, we provide evidence that the essential and broadly conserved WalR-WalK two component regulatory system continuously monitors changes in the activity of these hydrolases by sensing the cleavage products generated by these enzymes and modulating their levels and activity in response. The WalR-WalK pathway is conserved among many Gram-positive pathogens where it controls transcription of distinct sets of PG hydrolases. Cell wall remodeling in these bacteria may be subject to homeostatic control mechanisms similar to the one reported here.
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Affiliation(s)
| | - Yannick R Brunet
- Department of Microbiology, Harvard Medical School, Boston, United States
| | - Josué Flores-Kim
- Department of Microbiology, Harvard Medical School, Boston, United States
| | - David Z Rudner
- Department of Microbiology, Harvard Medical School, Boston, United States
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25
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Monk IR, Shaikh N, Begg SL, Gajdiss M, Sharkey LKR, Lee JYH, Pidot SJ, Seemann T, Kuiper M, Winnen B, Hvorup R, Collins BM, Bierbaum G, Udagedara SR, Morey JR, Pulyani N, Howden BP, Maher MJ, McDevitt CA, King GF, Stinear TP. Zinc-binding to the cytoplasmic PAS domain regulates the essential WalK histidine kinase of Staphylococcus aureus. Nat Commun 2019; 10:3067. [PMID: 31296851 PMCID: PMC6624279 DOI: 10.1038/s41467-019-10932-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 06/05/2019] [Indexed: 01/23/2023] Open
Abstract
WalKR (YycFG) is the only essential two-component regulator in the human pathogen Staphylococcus aureus. WalKR regulates peptidoglycan synthesis, but this function alone does not explain its essentiality. Here, to further understand WalKR function, we investigate a suppressor mutant that arose when WalKR activity was impaired; a histidine to tyrosine substitution (H271Y) in the cytoplasmic Per-Arnt-Sim (PASCYT) domain of the histidine kinase WalK. Introducing the WalKH271Y mutation into wild-type S. aureus activates the WalKR regulon. Structural analyses of the WalK PASCYT domain reveal a metal-binding site, in which a zinc ion (Zn2+) is tetrahedrally-coordinated by four amino acids including H271. The WalKH271Y mutation abrogates metal binding, increasing WalK kinase activity and WalR phosphorylation. Thus, Zn2+-binding negatively regulates WalKR. Promoter-reporter experiments using S. aureus confirm Zn2+ sensing by this system. Identification of a metal ligand recognized by the WalKR system broadens our understanding of this critical S. aureus regulon.
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Affiliation(s)
- Ian R Monk
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia.
| | - Nausad Shaikh
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Stephanie L Begg
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Mike Gajdiss
- University Clinics of Bonn, Institute of Medical Microbiology, Immunology and Parasitology, 53127, Bonn, Germany
| | - Liam K R Sharkey
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Jean Y H Lee
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Sacha J Pidot
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Torsten Seemann
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia.,Melbourne Bioinformatics, University of Melbourne, Melbourne, VIC, 3000, Australia
| | | | | | - Rikki Hvorup
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Gabriele Bierbaum
- University Clinics of Bonn, Institute of Medical Microbiology, Immunology and Parasitology, 53127, Bonn, Germany
| | - Saumya R Udagedara
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Jacqueline R Morey
- Department of Molecular and Biomedical Sciences, School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Neha Pulyani
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Benjamin P Howden
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Megan J Maher
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Christopher A McDevitt
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia.,Department of Molecular and Biomedical Sciences, School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, 3000, Australia.
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26
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Abstract
Dating back to the 1960s, initial studies on the staphylococcal cell wall were driven by the need to clarify the mode of action of the first antibiotics and the resistance mechanisms developed by the bacteria. During the following decades, the elucidation of the biosynthetic path and primary composition of staphylococcal cell walls was propelled by advances in microbial cell biology, specifically, the introduction of high-resolution analytical techniques and molecular genetic approaches. The field of staphylococcal cell wall gradually gained its own significance as the complexity of its chemical structure and involvement in numerous cellular processes became evident, namely its versatile role in host interactions, coordination of cell division and environmental stress signaling.This chapter includes an updated description of the anatomy of staphylococcal cell walls, paying particular attention to information from the last decade, under four headings: high-resolution analysis of the Staphylococcus aureus peptidoglycan; variations in peptidoglycan composition; genetic determinants and enzymes in cell wall synthesis; and complex functions of cell walls. The latest contributions to a more precise picture of the staphylococcal cell envelope were possible due to recently developed state-of-the-art microscopy and spectroscopy techniques and to a wide combination of -omics approaches, that are allowing to obtain a more integrative view of this highly dynamic structure.
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Affiliation(s)
- Rita Sobral
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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27
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Poupel O, Proux C, Jagla B, Msadek T, Dubrac S. SpdC, a novel virulence factor, controls histidine kinase activity in Staphylococcus aureus. PLoS Pathog 2018; 14:e1006917. [PMID: 29543889 PMCID: PMC5854430 DOI: 10.1371/journal.ppat.1006917] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 02/01/2018] [Indexed: 11/18/2022] Open
Abstract
The success of Staphylococcus aureus, as both a human and animal pathogen, stems from its ability to rapidly adapt to a wide spectrum of environmental conditions. Two-component systems (TCSs) play a crucial role in this process. Here, we describe a novel staphylococcal virulence factor, SpdC, an Abi-domain protein, involved in signal sensing and/or transduction. We have uncovered a functional link between the WalKR essential TCS and the SpdC Abi membrane protein. Expression of spdC is positively regulated by the WalKR system and, in turn, SpdC negatively controls WalKR regulon genes, effectively constituting a negative feedback loop. The WalKR system is mainly involved in controlling cell wall metabolism through regulation of autolysin production. We have shown that SpdC inhibits the WalKR-dependent synthesis of four peptidoglycan hydrolases, SceD, SsaA, LytM and AtlA, as well as impacting S. aureus resistance towards lysostaphin and cell wall antibiotics such as oxacillin and tunicamycin. We have also shown that SpdC is required for S. aureus biofilm formation and virulence in a murine septicemia model. Using protein-protein interactions in E. coli as well as subcellular localization in S. aureus, we showed that SpdC and the WalK kinase are both localized at the division septum and that the two proteins interact. In addition to WalK, our results indicate that SpdC also interacts with nine other S. aureus histidine kinases, suggesting that this membrane protein may act as a global regulator of TCS activity. Indeed, using RNA-Seq analysis, we showed that SpdC controls the expression of approximately one hundred genes in S. aureus, many of which belong to TCS regulons.
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Affiliation(s)
- Olivier Poupel
- Department of Microbiology, Biology of Gram-Positive Pathogens, Institut Pasteur, Paris, France
- ERL3526, CNRS, Paris, France
| | - Caroline Proux
- Transcriptome and EpiGenome, BioMics, Center for Innovation and Technological Research, Institut Pasteur, Paris, France
| | - Bernd Jagla
- Transcriptome and EpiGenome, BioMics, Center for Innovation and Technological Research, Institut Pasteur, Paris, France
- Center for Human Immunology, Center for Translational Science, Institut Pasteur, Paris, France
- Bioinformatics & Biostatistics HUB, Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris, France
| | - Tarek Msadek
- Department of Microbiology, Biology of Gram-Positive Pathogens, Institut Pasteur, Paris, France
- ERL3526, CNRS, Paris, France
- * E-mail: (TM); (SD)
| | - Sarah Dubrac
- Department of Microbiology, Biology of Gram-Positive Pathogens, Institut Pasteur, Paris, France
- ERL3526, CNRS, Paris, France
- * E-mail: (TM); (SD)
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28
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Takada H, Yoshikawa H. Essentiality and function of WalK/WalR two-component system: the past, present, and future of research. Biosci Biotechnol Biochem 2018. [PMID: 29514560 DOI: 10.1080/09168451.2018.1444466] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The WalK/WalR two-component system (TCS), originally identified in Bacillus subtilis, is very highly conserved in gram-positive bacteria, including several important pathogens. The WalK/WalR TCS appears to be involved in the growth of most bacterial species encoding it. Previous studies have indicated conserved functions of this system, defining this signal transduction pathway as a crucial regulatory system for cell wall metabolism. Because of such effects on essential functions, this system is considered a potential target for anti-infective therapeutics. In this review, we discuss the role of WalK/WalR TCS in different bacterial cells, focusing on the function of the genes in its regulon as well as the variations in walRK operon structure, its auxiliary proteins, and the composition of its regulon. We also discuss recent experimental data addressing its essential function and the potential type of signal being sensed by B. subtilis. This review also focuses on the potential future research.
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Affiliation(s)
- Hiraku Takada
- Department of Life Science and Research Center for Life Science, College of Science, Rikkyo University, Tokyo, Japan.,Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
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29
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Takada H, Shiwa Y, Takino Y, Osaka N, Ueda S, Watanabe S, Chibazakura T, Su'etsugu M, Utsumi R, Yoshikawa H. Essentiality of WalRK for growth in Bacillus subtilis and its role during heat stress. MICROBIOLOGY-SGM 2018; 164:670-684. [PMID: 29465029 DOI: 10.1099/mic.0.000625] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
WalRK is an essential two-component signal transduction system that plays a central role in coordinating cell wall synthesis and cell growth in Bacillus subtilis. However, the physiological role of WalRK and its essentiality for growth have not been elucidated. We investigated the behaviour of WalRK during heat stress and its essentiality for cell proliferation. We determined that the inactivation of the walHI genes which encode the negative modulator of WalK, resulted in growth defects and eventual cell lysis at high temperatures. Screening of suppressor mutations revealed that the inactivation of LytE, an dl-endopeptidase, restored the growth of the ΔwalHI mutant at high temperatures. Suppressor mutations that reduced heat induction arising from the walRK regulon were also mapped to the walK ORF. Therefore, we hypothesized that overactivation of LytE affects the phenotype of the ΔwalHI mutant. This hypothesis was corroborated by the overexpression of the negative regulator of LytE, IseA and PdaC, which rescued the growth of the ΔwalHI mutant at high temperatures. Elucidating the cause of the temperature sensitivity of the ΔwalHI mutant could explain the essentiality of WalRK. We proved that the constitutive expression of lytE or cwlO using a synthetic promoter uncouples these expressions from WalRK, and renders WalRK nonessential in the pdaC and iseA mutant backgrounds. We propose that the essentiality of WalRK is derived from the coordination of cell wall metabolism with cell growth by regulating dl-endopeptidase activity under various growth conditions.
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Affiliation(s)
- Hiraku Takada
- Department of Life Science and Research Center for Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan.,Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Yuh Shiwa
- Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Yuta Takino
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Natsuki Osaka
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Shuhei Ueda
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, 3327-204 Nakamachi, Nara-shi, Nara 631-8505, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Taku Chibazakura
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Masayuki Su'etsugu
- Department of Life Science and Research Center for Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
| | - Ryutaro Utsumi
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, 3327-204 Nakamachi, Nara-shi, Nara 631-8505, Japan
| | - Hirofumi Yoshikawa
- Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.,Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
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30
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Tomasini A, Moreau K, Chicher J, Geissmann T, Vandenesch F, Romby P, Marzi S, Caldelari I. The RNA targetome of Staphylococcus aureus non-coding RNA RsaA: impact on cell surface properties and defense mechanisms. Nucleic Acids Res 2017; 45:6746-6760. [PMID: 28379505 PMCID: PMC5499838 DOI: 10.1093/nar/gkx219] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 03/24/2017] [Indexed: 01/08/2023] Open
Abstract
The virulon of Staphyloccocus aureus is controlled by intricate connections between transcriptional and post-transcriptional regulators including proteins and small non-coding RNAs (sRNAs). Many of the sRNAs regulate gene expression through base-pairings with mRNAs. However, characterization of the direct sRNA targets in Gram-positive bacteria remained a difficult challenge. Here, we have applied and adapted the MS2-affinity purification approach coupled to RNA sequencing (MAPS) to determine the targetome of RsaA sRNA of S. aureus, known to repress the synthesis of the transcriptional regulator MgrA. Several mRNAs were enriched with RsaA expanding its regulatory network. Besides mgrA, several of these mRNAs encode a family of SsaA-like enzymes involved in peptidoglycan metabolism and the secreted anti-inflammatory FLIPr protein. Using a combination of in vivo and in vitro approaches, these mRNAs were validated as direct RsaA targets. Quantitative differential proteomics of wild-type and mutant strains corroborated the MAPS results. Additionally, it revealed that RsaA indirectly activated the synthesis of surface proteins supporting previous data that RsaA stimulated biofilm formation and favoured chronic infections. All together, this study shows that MAPS could also be easily applied in Gram-positive bacteria for identification of sRNA targetome.
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Affiliation(s)
- Arnaud Tomasini
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
| | - Karen Moreau
- CIRI, International Center for Infectiology Research, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Hospices Civils de Lyon, University of Lyon, F-69008, Lyon, France
| | | | - Thomas Geissmann
- CIRI, International Center for Infectiology Research, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Hospices Civils de Lyon, University of Lyon, F-69008, Lyon, France
| | - François Vandenesch
- CIRI, International Center for Infectiology Research, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Hospices Civils de Lyon, University of Lyon, F-69008, Lyon, France
| | - Pascale Romby
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
| | - Stefano Marzi
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
| | - Isabelle Caldelari
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
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31
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Cardona ST, Choy M, Hogan AM. Essential Two-Component Systems Regulating Cell Envelope Functions: Opportunities for Novel Antibiotic Therapies. J Membr Biol 2017; 251:75-89. [DOI: 10.1007/s00232-017-9995-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 10/20/2017] [Indexed: 01/22/2023]
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32
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Kant S, Asthana S, Missiakas D, Pancholi V. A novel STK1-targeted small-molecule as an "antibiotic resistance breaker" against multidrug-resistant Staphylococcus aureus. Sci Rep 2017; 7:5067. [PMID: 28698584 PMCID: PMC5505960 DOI: 10.1038/s41598-017-05314-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 06/15/2017] [Indexed: 01/28/2023] Open
Abstract
Ser/Thr protein kinase (STK1) plays a critical role in cell wall biosynthesis of and drug resistance in methicillin-resistant Staphylococcus aureus (MRSA). MRSA strains lacking STK1 become susceptible to failing cephalosporins, such as Ceftriaxone and Cefotaxime. STK1, despite being nonessential protein for MRSA survival, it can serve as an important therapeutic agent for combination therapy. Here, we report a novel small molecule quinazoline compound, Inh2-B1, which specifically inhibits STK1 activity by directly binding to its ATP-binding catalytic domain. Functional analyses encompassing in vitro growth inhibition of MRSA, and in vivo protection studies in mice against the lethal MRSA challenge indicated that at high concentration neither Inh2-B1 nor Ceftriaxone or Cefotaxime alone was able to inhibit the growth of bacteria or protect the challenged mice. However, the growth of MRSA was inhibited, and a significant protection in mice against the bacterial challenge was observed at a micromolar concentration of Ceftriaxone or Cefotaxime in the presence of Inh2-B1. Cell-dependent minimal to no toxicity of Inh2-B1, and its abilities to down-regulate cell wall hydrolase genes and disrupt the biofilm formation of MRSA clearly indicated that Inh2-B1 serves as a therapeutically important “antibiotic-resistance-breaker,” which enhances the bactericidal activity of Ceftriaxone/Cefotaxime against highly pathogenic MRSA infection.
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Affiliation(s)
- Sashi Kant
- Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Shailendra Asthana
- Drug Discovery Research Center, Translational Health Science and Technology Institute, Faridabad-Gurgaon Expressway, Haryana, India
| | | | - Vijay Pancholi
- Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio, USA.
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Novel Antibacterial Coating on Orthopedic Wires To Eliminate Pin Tract Infections. Antimicrob Agents Chemother 2017; 61:AAC.00442-17. [PMID: 28483964 DOI: 10.1128/aac.00442-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/04/2017] [Indexed: 12/21/2022] Open
Abstract
Novel approaches to the prevention of microbial infections after the insertion of orthopedic external fixators are in great demand because of the extremely high incidence rates of such infections, which can reach up to 100% with longer implant residence times. Monolaurin is an antimicrobial agent with a known safety record that is broadly used in the food and cosmetic industries; however, its use in antimicrobial coatings of medical devices has not been studied in much detail. Here, we report the use of monolaurin as an antibacterial coating on external fixators for the first time. Monolaurin-coated Kirschner wires (K-wires) showed excellent antibacterial properties against three different bacterial strains, i.e., methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), and Staphylococcus epidermidis Approximately 6.0-log reductions of both planktonic and adherent bacteria were achieved using monolaurin-coated K-wires, but monolaurin-coated K-wires did not show any observable cytotoxicity with mouse osteoblast cell cultures. Overall, monolaurin-coated K-wires could be promising as potent antimicrobial materials for orthopedic surgery.
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Xu T, Wu Y, Lin Z, Bertram R, Götz F, Zhang Y, Qu D. Identification of Genes Controlled by the Essential YycFG Two-Component System Reveals a Role for Biofilm Modulation in Staphylococcus epidermidis. Front Microbiol 2017; 8:724. [PMID: 28491057 PMCID: PMC5405149 DOI: 10.3389/fmicb.2017.00724] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/07/2017] [Indexed: 01/11/2023] Open
Abstract
Biofilms play a crucial role in the pathogenicity of Staphylococcus epidermidis, while little is known about whether the essential YycFG two-component signal transduction system (TCS) is involved in biofilm formation. We used antisense RNA (asRNA) to silence the yycFG TCS in order to study its regulatory functions in S. epidermidis. Strain 1457 expressing asRNAyycF exhibited a significant delay (~4–5 h) in entry to log phase, which was partially complemented by overexpressing ssaA. The expression of asRNAyycF and asRNAyycG resulted in a 68 and 50% decrease in biofilm formation at 6 h, respectively, while they had no significant inhibitory effect on 12 h biofilm formation. The expression of asRNAyycF led to a ~5-fold increase in polysaccharide intercellular adhesion (PIA) production, but it did not affect the expression of accumulation-associated protein (Aap) or the release of extracellular DNA. Consistently, quantitative real-time PCR showed that silencing yycF resulted in an increased transcription of biofilm-related genes, including icaA, arlR, sarA, sarX, and sbp. An in silico search of the YycF regulon for the conserved YycF recognition pattern and a modified motif in S. epidermidis, along with additional gel shift and DNase I footprinting assays, showed that arlR, sarA, sarX, and icaA are directly regulated by YycF. Our data suggests that YycFG modulates S. epidermidis biofilm formation in an ica-dependent manner.
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Affiliation(s)
- Tao Xu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Department of Medical Microbiology and Parasitology, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan UniversityShanghai, China.,Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan UniversityShanghai, China
| | - Yang Wu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Department of Medical Microbiology and Parasitology, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan UniversityShanghai, China
| | - Zhiwei Lin
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Department of Medical Microbiology and Parasitology, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan UniversityShanghai, China
| | - Ralph Bertram
- Klinikum Nürnberg Medical School GmbH, Research Department, Paracelsus Medical UniversityNuremberg, Germany.,Department of Microbial Genetics, Faculty of Science, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of TübingenTübingen, Germany
| | - Friedrich Götz
- Department of Microbial Genetics, Faculty of Science, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of TübingenTübingen, Germany
| | - Ying Zhang
- Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan UniversityShanghai, China.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins UniversityBaltimore, MD, USA
| | - Di Qu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Department of Medical Microbiology and Parasitology, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan UniversityShanghai, China
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35
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Hardt P, Engels I, Rausch M, Gajdiss M, Ulm H, Sass P, Ohlsen K, Sahl HG, Bierbaum G, Schneider T, Grein F. The cell wall precursor lipid II acts as a molecular signal for the Ser/Thr kinase PknB of Staphylococcus aureus. Int J Med Microbiol 2016; 307:1-10. [PMID: 27989665 DOI: 10.1016/j.ijmm.2016.12.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/22/2016] [Accepted: 12/10/2016] [Indexed: 12/23/2022] Open
Abstract
The assembly of the bacterial cell wall requires synchronization of a multitude of biosynthetic machineries and regulatory networks. The eukaryotic-like serine/threonine kinase PknB has been implicated in coordinating cross-wall formation, autolysis and cell division in Staphylococcus aureus. However, the signal molecule sensed by this kinase remained elusive so far. Here, we provide compelling biochemical evidence that PknB interacts with the ultimate cell wall precursor lipid II, triggering kinase activity. Moreover, we observed crosstalk of PknB with the two component system WalKR and identified the early cell division protein FtsZ as another PknB phosphorylation substrate in S. aureus. In agreement with the implied role in regulation of cell envelope metabolism, we found PknB to preferentially localize to the septum of S. aureus and the PASTA domains to be crucial for recruitment to this site. The data provide a model for the contribution of PknB to control cell wall metabolism and cell division.
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Affiliation(s)
- Patrick Hardt
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany
| | - Ina Engels
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany; German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Marvin Rausch
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany; German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Mike Gajdiss
- Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, Bonn, Germany
| | - Hannah Ulm
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany
| | - Peter Sass
- Interfaculty Institute for Microbiology and Infection Medicine, Department for Microbial Bioactive Compounds, University of Tuebingen, Tuebingen, Germany
| | - Knut Ohlsen
- Institute for Molecular Infection Biology, University of Wuerzburg, Wuerzburg, Germany
| | - Hans-Georg Sahl
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany; Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, Bonn, Germany
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, University of Bonn, Bonn, Germany
| | - Tanja Schneider
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany; German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany.
| | - Fabian Grein
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany; German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany.
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36
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Cameron DR, Jiang JH, Kostoulias X, Foxwell DJ, Peleg AY. Vancomycin susceptibility in methicillin-resistant Staphylococcus aureus is mediated by YycHI activation of the WalRK essential two-component regulatory system. Sci Rep 2016; 6:30823. [PMID: 27600558 PMCID: PMC5013275 DOI: 10.1038/srep30823] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 06/09/2016] [Indexed: 02/01/2023] Open
Abstract
The treatment of infections caused by methicillin-resistant Staphylococcus aureus is complicated by the emergence of strains with intermediate-level resistance to vancomycin (termed VISA). We have characterised a molecular pathway involved in the in vivo evolution of VISA mediated by the regulatory proteins YycH and YycI. In contrast to their function in other bacterial species, we report a positive role for these auxiliary proteins in regulation of the two-component regulator WalRK. Transcriptional profiling of yycH and yycI deletion mutants revealed downregulation of the ‘WalRK regulon’ including cell wall hydrolase genes atlA and sle1, with functional autolysis assays supporting these data by showing an impaired autolytic phenotype for each deletion strain. Using bacterial-two hybrid assays, we showed that YycH and YycI interact, and that YycHI also interacts with the sensor kinase WalK, forming a ternary protein complex. Mutation to YycH or YycI associated with clinical VISA strains had a deleterious impact on the YycHI/WalK complex, suggesting that the interaction is important for the regulation of WalRK. Taken together, we have described a novel antibiotic resistance strategy for the human pathogen S. aureus, whereby YycHI mutations are selected for in vivo leading to reduced WalRK activation, impaired cell wall turnover and ultimately reduced vancomycin efficacy.
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Affiliation(s)
- David R Cameron
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Jhih-Hang Jiang
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Xenia Kostoulias
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Daniel J Foxwell
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Anton Y Peleg
- Department of Microbiology, Monash University, Melbourne, Australia.,Department of Infectious Diseases, Alfred Hospital and Monash University, Melbourne, Australia
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37
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Poupel O, Moyat M, Groizeleau J, Antunes LCS, Gribaldo S, Msadek T, Dubrac S. Transcriptional Analysis and Subcellular Protein Localization Reveal Specific Features of the Essential WalKR System in Staphylococcus aureus. PLoS One 2016; 11:e0151449. [PMID: 26999783 PMCID: PMC4801191 DOI: 10.1371/journal.pone.0151449] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 02/29/2016] [Indexed: 11/21/2022] Open
Abstract
The WalKR two-component system, controlling cell wall metabolism, is highly conserved among Bacilli and essential for cell viability. In Staphylococcus aureus, walR and walK are followed by three genes of unknown function: walH, walI and walJ. Sequence analysis and transcript mapping revealed a unique genetic structure for this locus in S. aureus: the last gene of the locus, walJ, is transcribed independently, whereas transcription of the tetra-cistronic walRKHI operon occurred from two independent promoters located upstream from walR. Protein topology analysis and protein-protein interactions in E. coli as well as subcellular localization in S. aureus allowed us to show that WalH and WalI are membrane-bound proteins, which associate with WalK to form a complex at the cell division septum. While these interactions suggest that WalH and WalI play a role in activity of the WalKR regulatory pathway, deletion of walH and/or walI did not have a major effect on genes whose expression is strongly dependent on WalKR or on associated phenotypes. No effect of WalH or WalI was seen on tightly controlled WalKR regulon genes such as sle1 or saouhsc_00773, which encodes a CHAP-domain amidase. Of the genes encoding the two major S. aureus autolysins, AtlA and Sle1, only transcription of atlA was increased in the ΔwalH or ΔwalI mutants. Likewise, bacterial autolysis was not increased in the absence of WalH and/or WalI and biofilm formation was lowered rather than increased. Our results suggest that contrary to their major role as WalK inhibitors in B. subtilis, the WalH and WalI proteins have evolved a different function in S. aureus, where they are more accessory. A phylogenomic analysis shows a striking conservation of the 5 gene wal cluster along the evolutionary history of Bacilli, supporting the key importance of this signal transduction system, and indicating that the walH and walI genes were lost in the ancestor of Streptococcaceae, leading to their atypical 3 wal gene cluster, walRKJ.
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Affiliation(s)
- Olivier Poupel
- Institut Pasteur, Biology of Gram-Positive Pathogens, Department of Microbiology, Paris, France
- CNRS, ERL3526, Paris, France
| | - Mati Moyat
- Institut Pasteur, Biology of Gram-Positive Pathogens, Department of Microbiology, Paris, France
- CNRS, ERL3526, Paris, France
| | - Julie Groizeleau
- Institut Pasteur, Biology of Gram-Positive Pathogens, Department of Microbiology, Paris, France
- CNRS, ERL3526, Paris, France
| | - Luísa C. S. Antunes
- Institut Pasteur, Molecular Biology of Gene in Extremophiles, Department of Microbiology, Paris, France
| | - Simonetta Gribaldo
- Institut Pasteur, Molecular Biology of Gene in Extremophiles, Department of Microbiology, Paris, France
| | - Tarek Msadek
- Institut Pasteur, Biology of Gram-Positive Pathogens, Department of Microbiology, Paris, France
- CNRS, ERL3526, Paris, France
- * E-mail: (TM); (SD)
| | - Sarah Dubrac
- Institut Pasteur, Biology of Gram-Positive Pathogens, Department of Microbiology, Paris, France
- CNRS, ERL3526, Paris, France
- * E-mail: (TM); (SD)
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38
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Lioliou E, Fechter P, Caldelari I, Jester BC, Dubrac S, Helfer AC, Boisset S, Vandenesch F, Romby P, Geissmann T. Various checkpoints prevent the synthesis of Staphylococcus aureus peptidoglycan hydrolase LytM in the stationary growth phase. RNA Biol 2016; 13:427-40. [PMID: 26901414 DOI: 10.1080/15476286.2016.1153209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In Staphylococcus aureus, peptidoglycan metabolism plays a role in the host inflammatory response and pathogenesis. Transcription of the peptidoglycan hydrolases is activated by the essential 2-component system WalKR at low cell density. During stationary growth phase, WalKR is not active and transcription of the peptidoglycan hydrolase genes is repressed. In this work, we studied regulation of expression of the glycylglycine endopeptidase LytM. We show that, in addition to the transcriptional regulation mediated by WalKR, the synthesis of LytM is negatively controlled by a unique mechanism at the stationary growth phase. We have identified 2 different mRNAs encoding lytM, which vary in the length of their 5' untranslated (5'UTR) regions. LytM is predominantly produced from the WalKR-regulated mRNA transcript carrying a short 5'UTR. The lytM mRNA is also transcribed as part of a polycistronic operon with the upstream SA0264 gene and is constitutively expressed. Although SA0264 protein can be synthesized from the longer operon transcript, lytM cannot be translated because its ribosome-binding site is sequestered into a translationally inactive secondary structure. In addition, the effector of the agr system, RNAIII, can inhibit translation of lytM present on the operon without altering the transcript level but does not have an effect on the translation of the upstream gene. We propose that this dual regulation of lytM expression, at the transcriptional and post-transcriptional levels, contributes to prevent cell wall damage during the stationary phase of growth.
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Affiliation(s)
- Efthimia Lioliou
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Pierre Fechter
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Isabelle Caldelari
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Brian C Jester
- b Institute of Systems and Synthetic Biology, University of Evry-Val-d'Essonne, CNRS FRE3561 , Evry , France
| | - Sarah Dubrac
- c Unité de Biologie des Bactéries pathogènes à Gram-positif, Institut Pasteur , 28 rue du Dr Roux, Paris , France
| | - Anne-Catherine Helfer
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Sandrine Boisset
- d CIRI, Center International de Recherche en Infectiologie - Inserm U1111 - Université Lyon 1 - Ecole Normale Supérieure de Lyon - CNRS UMR5308 , 21 Avenue Tony Garnier, LYON cedex 07 , France
| | - François Vandenesch
- d CIRI, Center International de Recherche en Infectiologie - Inserm U1111 - Université Lyon 1 - Ecole Normale Supérieure de Lyon - CNRS UMR5308 , 21 Avenue Tony Garnier, LYON cedex 07 , France
| | - Pascale Romby
- a Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC , 15 rue René Descartes, Strasbourg , France
| | - Thomas Geissmann
- d CIRI, Center International de Recherche en Infectiologie - Inserm U1111 - Université Lyon 1 - Ecole Normale Supérieure de Lyon - CNRS UMR5308 , 21 Avenue Tony Garnier, LYON cedex 07 , France
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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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40
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Nair N, Vinod V, Suresh MK, Vijayrajratnam S, Biswas L, Peethambaran R, Vasudevan AK, Biswas R. Amidase, a cell wall hydrolase, elicits protective immunity against Staphylococcus aureus and S. epidermidis. Int J Biol Macromol 2015; 77:314-21. [PMID: 25841371 DOI: 10.1016/j.ijbiomac.2015.03.047] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Revised: 03/11/2015] [Accepted: 03/12/2015] [Indexed: 02/08/2023]
Abstract
The morbidity and the mortality associated with Staphylococcus aureus and S. epidermidis infections have greatly increased due to the rapid emergence of highly virulent and antibiotic resistant strains. Development of a vaccine-based therapy is greatly desired. However, no staphylococcal vaccine is available till date. In this study, we have identified Major amidase (Atl-AM) as a prime candidate for future vaccine design against these pathogens. Atl-AM is a multi-functional non-covalently cell wall associated protein which is involved in staphylococcal cell separation after cell division, host extracellular matrix adhesion and biofilm formation. Atl-AM is present on the surface of diverse S. aureus and S. epidermidis strains. When used in combination with Freund's adjuvant, Atl-AM generated a mixed Th1 and Th2 mediated immune response which is skewed more toward Th1; and showed increased production of opsonophagocytic IgG2a and IgG2b antibodies. Significant protective immune response was observed when vaccinated mice were challenged with S. aureus or S. epidermidis. Vaccination prevented the systemic dissemination of both organisms. Our results demonstrate the remarkable efficacy of Atl-AM as a vaccine candidate against both of these pathogens.
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Affiliation(s)
- Nisha Nair
- Amrita Center for Nanoscience and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, AIMS - Ponekkara, Cochin, Kerala 682041, India
| | - Vivek Vinod
- Amrita Center for Nanoscience and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, AIMS - Ponekkara, Cochin, Kerala 682041, India
| | - Maneesha K Suresh
- Amrita Center for Nanoscience and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, AIMS - Ponekkara, Cochin, Kerala 682041, India
| | - Sukhithasri Vijayrajratnam
- Amrita Center for Nanoscience and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, AIMS - Ponekkara, Cochin, Kerala 682041, India
| | - Lalitha Biswas
- Amrita Center for Nanoscience and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, AIMS - Ponekkara, Cochin, Kerala 682041, India
| | - Reshmi Peethambaran
- Department of Veterinary Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, AIMS - Ponekkara, Cochin, Kerala 682041, India
| | - Anil Kumar Vasudevan
- Department of Microbiology, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, AIMS - Ponekkara, Cochin, Kerala 682041, India
| | - Raja Biswas
- Amrita Center for Nanoscience and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, AIMS - Ponekkara, Cochin, Kerala 682041, India.
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41
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Hattangady DS, Singh AK, Muthaiyan A, Jayaswal RK, Gustafson JE, Ulanov AV, Li Z, Wilkinson BJ, Pfeltz RF. Genomic, Transcriptomic and Metabolomic Studies of Two Well-Characterized, Laboratory-Derived Vancomycin-Intermediate Staphylococcus aureus Strains Derived from the Same Parent Strain. Antibiotics (Basel) 2015; 4:76-112. [PMID: 27025616 PMCID: PMC4790321 DOI: 10.3390/antibiotics4010076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 11/20/2014] [Accepted: 12/10/2014] [Indexed: 11/16/2022] Open
Abstract
Complete genome comparisons, transcriptomic and metabolomic studies were performed on two laboratory-selected, well-characterized vancomycin-intermediate Staphylococcus aureus (VISA) derived from the same parent MRSA that have changes in cell wall composition and decreased autolysis. A variety of mutations were found in the VISA, with more in strain 13136p(-)m⁺V20 (vancomycin MIC = 16 µg/mL) than strain 13136p(-)m⁺V5 (MIC = 8 µg/mL). Most of the mutations have not previously been associated with the VISA phenotype; some were associated with cell wall metabolism and many with stress responses, notably relating to DNA damage. The genomes and transcriptomes of the two VISA support the importance of gene expression regulation to the VISA phenotype. Similarities in overall transcriptomic and metabolomic data indicated that the VISA physiologic state includes elements of the stringent response, such as downregulation of protein and nucleotide synthesis, the pentose phosphate pathway and nutrient transport systems. Gene expression for secreted virulence determinants was generally downregulated, but was more variable for surface-associated virulence determinants, although capsule formation was clearly inhibited. The importance of activated stress response elements could be seen across all three analyses, as in the accumulation of osmoprotectant metabolites such as proline and glutamate. Concentrations of potential cell wall precursor amino acids and glucosamine were increased in the VISA strains. Polyamines were decreased in the VISA, which may facilitate the accrual of mutations. Overall, the studies confirm the wide variability in mutations and gene expression patterns that can lead to the VISA phenotype.
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Affiliation(s)
- Dipti S Hattangady
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA.
| | - Atul K Singh
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA.
| | - Arun Muthaiyan
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA.
| | | | - John E Gustafson
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Alexander V Ulanov
- Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Urbana, IL 61807, USA.
| | - Zhong Li
- Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Urbana, IL 61807, USA.
| | - Brian J Wilkinson
- School of Biological Sciences, Illinois State University, Normal, IL 61790, USA.
| | - Richard F Pfeltz
- BD Diagnostic Systems, Microbiology Research and Development, Sparks, MD 21152, USA.
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42
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Characterization of a novel two-component regulatory system, HptRS, the regulator for the hexose phosphate transport system in Staphylococcus aureus. Infect Immun 2015; 83:1620-8. [PMID: 25644013 DOI: 10.1128/iai.03109-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hexose phosphate is an important carbon source within the cytoplasm of host cells. Bacterial pathogens that invade, survive, and multiply within various host epithelial cells exploit hexose phosphates from the host cytoplasm through the hexose phosphate transport (HPT) system to gain energy and synthesize cellular components. In Escherichia coli, the HPT system consists of a two-component regulatory system (UhpAB) and a phosphate sensor protein (UhpC) that tightly regulate expression of a hexose phosphate transporter (UhpT). Although growing evidence suggests that Staphylococcus aureus also can invade, survive, and multiply within various host epithelial cells, the genetic elements involved in the HPT system in S. aureus have not been characterized yet. In this study, we identified and characterized the HPT system in S. aureus that includes the hptRS (a novel two-component regulatory system), the hptA (a putative phosphate sensor), and the uhpT (a hexose phosphate transporter) genes. The hptA, hptRS, and uhpT markerless deletion mutants were generated by an allelic replacement method using a modified pMAD-CM-GFPuv vector system. We demonstrated that both hptA and hptRS are required to positively regulate transcription of uhpT in response to extracellular phosphates, such as glycerol-3-phosphate (G3P), glucose-6-phosphate (G6P), and fosfomycin. Mutational studies revealed that disruption of the hptA, hptRS, or uhpT gene impaired the growth of bacteria when the available carbon source was limited to G6P, impaired survival/multiplication within various types of host cells, and increased resistance to fosfomycin. The results of this study suggest that the HPT system plays an important role in adaptation of S. aureus within the host cells and could be an important target for developing novel antistaphylococcal therapies.
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43
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The Role of Two-Component Signal Transduction Systems in Staphylococcus aureus Virulence Regulation. Curr Top Microbiol Immunol 2015; 409:145-198. [PMID: 26728068 DOI: 10.1007/82_2015_5019] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Staphylococcus aureus is a versatile, opportunistic human pathogen that can asymptomatically colonize a human host but can also cause a variety of cutaneous and systemic infections. The ability of S. aureus to adapt to such diverse environments is reflected in the presence of complex regulatory networks fine-tuning metabolic and virulence gene expression. One of the most widely distributed mechanisms is the two-component signal transduction system (TCS) which allows a pathogen to alter its gene expression profile in response to environmental stimuli. The simpler TCSs consist of only a transmembrane histidine kinase (HK) and a cytosolic response regulator. S. aureus encodes a total of 16 conserved pairs of TCSs that are involved in diverse signalling cascades ranging from global virulence gene regulation (e.g. quorum sensing by the Agr system), the bacterial response to antimicrobial agents, cell wall metabolism, respiration and nutrient sensing. These regulatory circuits are often interconnected and affect each other's expression, thus fine-tuning staphylococcal gene regulation. This manuscript gives an overview of the current knowledge of staphylococcal environmental sensing by TCS and its influence on virulence gene expression and virulence itself. Understanding bacterial gene regulation by TCS can give major insights into staphylococcal pathogenicity and has important implications for knowledge-based drug design and vaccine formulation.
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44
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Mechanism of reduced vancomycin susceptibility conferred by walK mutation in community-acquired methicillin-resistant Staphylococcus aureus strain MW2. Antimicrob Agents Chemother 2014; 59:1352-5. [PMID: 25451044 DOI: 10.1128/aac.04290-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Point mutations with unclear molecular mechanisms are often associated with vancomycin resistance in Staphylococcus aureus. Here, we observed that the walK (G223D) mutation caused decreased expression of genes associated with cell wall metabolism, decreased autolytic activity, thickened cell walls, and reduced vancomycin susceptibility. A phosphorylation assay showed that WalK (G223D) exhibited reduced autophosphorylation, which led to reduced phosphorylation of WalR. An electrophoretic mobility shift assay indicated that WalK (G223D)-phosphorylated WalR had a reduced capacity to bind to the atlA promoter.
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45
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Abstract
Staphylococcal protein A (SpA) is anchored to the cell wall envelope of Staphylococcus aureus by sortase A, which links the threonyl (T) of its C-terminal LPXTG motif to peptidoglycan cross-bridges (i.e., Gly5). SpA binds the Fcγ domains of IgG and protects staphylococci from opsonophagocytic clearance. Moreover, SpA cross-links B-cell receptors to modify host adaptive immune responses. The mechanisms whereby SpA is released from the bacterial surface to access the host's immune system are not known. Here we demonstrate that SpA is released with murein tetrapeptide-tetraglycyl [L-Ala-D-iGln-(SpA-Gly5)L-Lys-D-Ala-Gly4] linked to its C-terminal threonyl. LytN, a cross-wall murein hydrolase, contributes to the release of SpA by removing amino sugars [i.e., N-acetylmuramic acid-N-acetylglucosamine (MurNAc-GlcNAc)] from attached peptidoglycan, whereas LytM, a pentaglycyl-endopeptidase, triggers polypeptide release from the bacterial envelope. A model is proposed whereby murein hydrolases cleave the anchor structure of released SpA to modify host immune responses.
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46
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Comparative genomic and transcriptomic analyses of NaCl-tolerant Staphylococcus sp. OJ82 isolated from fermented seafood. Appl Microbiol Biotechnol 2013; 98:807-22. [PMID: 24346282 DOI: 10.1007/s00253-013-5436-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/25/2013] [Accepted: 11/26/2013] [Indexed: 12/25/2022]
Abstract
Bacteria belonging to the Staphylococcus genus reside in various natural environments; however, only disease-associated Staphylococcus strains have received attention while ecological function and physiologies of non-pathogenic strains were often neglected. Because high level of tolerance against NaCl is a common trait of Staphylococcus, we investigated the characteristics of halotolerance in Staphylococcus sp. OJ82 isolated from fermented seafood containing a high concentration of NaCl. Among the 292 isolates screened, OJ82 showed the highest β-galactosidase and extracellular protease activities under high-salt conditions. Comparative genomic analysis with other Staphylococcus strains showed that (a) replication origins are highly conserved, (b) the OJ82 strain has a high number of amino acid transport- and metabolism-related genes, and (c) OJ82 has many unique proteins (15 %) and 12 prophage-related genomic islands. RNA-seq analysis under high-salt conditions showed that genes involved in cell membranes, transport, osmotic stress, ATP synthesis, and translation are highly expressed. OJ82 may use the ribulose monophosphate pathway to detoxify some toxic intermediates under high-salt conditions. Six new and three known non-coding small RNAs of the OJ82 strain were also found in the RNA-seq analysis. Genomic and transcriptomic analyses identified target β-galactosidase and extracellular protease. Interestingly, the OJ82 strain became resistant to bacteriocin produced by the Bacillus strain only under high-salt conditions. Our data showed that the OJ82 strain adapted to high-salt conditions by expressing core cellular processes (translation, ATP production) and defense genes (membrane synthesis, compatible solute transports, ribulose monophosphate pathway) could survive bacteriocin exposure under high-salt conditions.
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47
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The dynamics of peptidoglycan structure and function: conference report on the 3rd Great Wall Symposium. Res Microbiol 2013; 165:60-7. [PMID: 24239960 DOI: 10.1016/j.resmic.2013.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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48
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Abstract
Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents.
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49
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Quiblier C, Seidl K, Roschitzki B, Zinkernagel AS, Berger-Bächi B, Senn MM. Secretome analysis defines the major role of SecDF in Staphylococcus aureus virulence. PLoS One 2013; 8:e63513. [PMID: 23658837 PMCID: PMC3643904 DOI: 10.1371/journal.pone.0063513] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 04/02/2013] [Indexed: 01/27/2023] Open
Abstract
The Sec pathway plays a prominent role in protein export and membrane insertion, including the secretion of major bacterial virulence determinants. The accessory Sec constituent SecDF has been proposed to contribute to protein export. Deletion of Staphylococcus aureus secDF has previously been shown to reduce resistance, to alter cell separation, and to change the expression of certain virulence factors. To analyse the impact of the secDF deletion in S. aureus on protein secretion, a quantitative secretome analysis was performed. Numerous Sec signal containing proteins involved in virulence were found to be decreased in the supernatant of the secDF mutant. However, two Sec-dependent hydrolases were increased in comparison to the wild type, suggesting additional indirect, regulatory effects to occur upon deletion of secDF. Adhesion, invasion, and cytotoxicity of the secDF mutant were reduced in human umbilical vein endothelial cells. Virulence was significantly reduced using a Galleria mellonella insect model. Altogether, SecDF is a promising therapeutic target for controlling S. aureus infections.
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Affiliation(s)
- Chantal Quiblier
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Kati Seidl
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Bernd Roschitzki
- Functional Genomics Center Zurich, Swiss Federal Institute of Technology and University of Zurich, Zurich, Switzerland
| | - Annelies S. Zinkernagel
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | | - Maria M. Senn
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
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50
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Decreased vancomycin susceptibility in Staphylococcus aureus caused by IS256 tempering of WalKR expression. Antimicrob Agents Chemother 2013; 57:3240-9. [PMID: 23629723 DOI: 10.1128/aac.00279-13] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Vancomycin-intermediate Staphylococcus aureus (VISA) strains often arise by mutations in the essential two-component regulator walKR; however their impact on walKR function has not been definitively established. Here, we investigated 10 MRSA strains recovered serially after exposure of vancomycin-susceptible S. aureus (VSSA) JKD6009 to simulated human vancomycin dosing regimens (500 mg to 4,000 mg every 12 h) using a 10-day hollow fiber infection model. After continued exposure to the vancomycin regimens, two isolates displayed reduced susceptibility to both vancomycin and daptomycin, developing independent IS256 insertions in the walKR 5' untranslated region (5' UTR). Quantitative reverse transcription-PCR (RT-PCR) revealed a 50% reduction in walKR gene expression in the IS256 mutants compared to the VSSA parent. Green fluorescent protein (GFP) reporter analysis, promoter mapping, and site-directed mutagenesis confirmed these findings and showed that the IS256 insertions had replaced two SigA-like walKR promoters with weaker, hybrid promoters. Removal of IS256 reverted the phenotype to VSSA, showing that reduced expression of WalKR did induce the VISA phenotype. Analysis of selected WalKR-regulated autolysins revealed upregulation of ssaA but no change in expression of sak and sceD in both IS256 mutants. Whole-genome sequencing of the two mutants revealed an additional IS256 insertion within agrC for one mutant, and we confirmed that this mutation abolished agr function. These data provide the first substantial analysis of walKR promoter function and show that prolonged vancomycin exposure can result in VISA through an IS256-mediated reduction in walKR expression; however, the mechanisms by which this occurs remain to be determined.
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