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Sekar S, Schwarzbach S, Nega M, Bloes DA, Smeds E, Kretschmer D, Foster TJ, Heilbronner S. SLUSH peptides of the PSMβ family enable Staphylococcus lugdunensis to use erythrocytes as a sole source of nutrient iron. FASEB J 2024; 38:e23881. [PMID: 39166718 DOI: 10.1096/fj.202400335r] [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: 02/13/2024] [Revised: 07/08/2024] [Accepted: 07/31/2024] [Indexed: 08/23/2024]
Abstract
During infection, the host employs nutritional immunity to restrict access to iron. Staphylococcus lugdunensis has been recognized for its ability to utilize host-derived heme to overcome iron restriction. However, the mechanism behind this process involves the release of hemoglobin from erythrocytes, and the hemolytic factors of S. lugdunensis remain poorly understood. S. lugdunensis encodes four phenol-soluble modulins (PSMs), short peptides with hemolytic activity. The peptides SLUSH A, SLUSH B, and SLUSH C are β-type PSMs, and OrfX is an α-type PSM. Our study shows the SLUSH locus to be essential for the hemolytic phenotype of S. lugdunensis. All four peptides individually exhibited hemolytic activity against human and sheep erythrocytes, but synergism with sphingomyelinase was observed exclusively against sheep erythrocytes. Furthermore, our findings demonstrate that SLUSH is crucial for allowing the utilization of erythrocytes as the sole source of nutritional iron and confirm the transcriptional regulation of SLUSH by Agr. Additionally, our study reveals that SLUSH peptides stimulate the human immune system. Our analysis identifies SLUSH as a pivotal hemolytic factor of S. lugdunensis and demonstrates its concerted action with heme acquisition systems to overcome iron limitation in the presence of host erythrocytes.
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Affiliation(s)
- Sharmila Sekar
- Department of Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine, Institute for Medical Microbiology and Hygiene, UKT Tübingen, Tübingen, Germany
| | - Selina Schwarzbach
- Department of Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine, Institute for Medical Microbiology and Hygiene, UKT Tübingen, Tübingen, Germany
| | - Mulugeta Nega
- Department of Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Dominik Alexander Bloes
- Department of Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine, Institute for Medical Microbiology and Hygiene, UKT Tübingen, Tübingen, Germany
| | - Emanuel Smeds
- Lund Protein Production Platform, Department of Biology, Lund University, Lund, Sweden
| | - Dorothee Kretschmer
- Department of Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine, Institute for Medical Microbiology and Hygiene, UKT Tübingen, Tübingen, Germany
| | - Timothy J Foster
- Trinity College Dublin, The Moyne Institute of Preventive Medicine, Dublin, Ireland
| | - Simon Heilbronner
- Department of Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine, Institute for Medical Microbiology and Hygiene, UKT Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Tübingen, Germany
- Faculty of Biology, Microbiology, Ludwig Maximilians Universität München, Martinsried, Germany
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2
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Kelly AM, McCarthy KN, Claxton TJ, Carlile SR, O'Brien EC, Vozza EG, Mills KH, McLoughlin RM. IL-10 inhibition during immunization improves vaccine-induced protection against Staphylococcus aureus infection. JCI Insight 2024; 9:e178216. [PMID: 38973612 PMCID: PMC11383370 DOI: 10.1172/jci.insight.178216] [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: 12/05/2023] [Accepted: 05/22/2024] [Indexed: 07/09/2024] Open
Abstract
Staphylococcus aureus is a major human pathogen. An effective anti-S. aureus vaccine remains elusive as the correlates of protection are ill-defined. Targeting specific T cell populations is an important strategy for improving anti-S. aureus vaccine efficacy. Potential bottlenecks that remain are S. aureus-induced immunosuppression and the impact this might have on vaccine-induced immunity. S. aureus induces IL-10, which impedes effector T cell responses, facilitating persistence during both colonization and infection. Thus, it was hypothesized that transient targeting of IL-10 might represent an innovative way to improve vaccine efficacy. In this study, IL-10 expression was elevated in the nares of persistent carriers of S. aureus, and this was associated with reduced systemic S. aureus-specific Th1 responses. This suggests that systemic responses are remodeled because of commensal exposure to S. aureus, which negatively implicates vaccine function. To provide proof of concept that targeting immunosuppressive responses during immunization may be a useful approach to improve vaccine efficacy, we immunized mice with T cell-activating vaccines in combination with IL-10-neutralizing antibodies. Blocking IL-10 during vaccination enhanced effector T cell responses and improved bacterial clearance during subsequent systemic and subcutaneous infection. Taken together, these results reveal a potentially novel strategy for improving anti-S. aureus vaccine efficacy.
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Affiliation(s)
| | - Karen N McCarthy
- Host-Pathogen Interactions Group and
- Immune Regulation Research Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | | | | | | | | | - Kingston Hg Mills
- Immune Regulation Research Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
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Fung WW, SZE RKH, Szeto CC, Chow KM. Staphylococcus lugdunensis Peritoneal Dialysis-Related Peritonitis: A Matched Comparative Analysis. Kidney Med 2024; 6:100811. [PMID: 38650953 PMCID: PMC11033185 DOI: 10.1016/j.xkme.2024.100811] [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: 04/25/2024] Open
Abstract
Rationale & Objective Staphylococcus lugdunensis (S lugdunensis) is a coagulase-negative staphylococcus species that has been increasingly recognized to cause serious infections with virulence resembling Staphylococcus aureus (S aureus). No studies have evaluated the characteristics and outcomes of patients with S lugdunensis peritoneal dialysis-related peritonitis compared with those with S aureus peritonitis. We aim to evaluate the clinical course of peritonitis as caused by these organisms. Study Design A retrospective matched comparative analysis involving a single tertiary center from July 2000 to July 2020. Setting & Participants Forty-eight episodes of S aureus peritonitis were matched to 19 cases of S lugdunensis peritonitis. Analytical Approach The cases were individually matched for year of peritonitis, sex, age (±10 years), and Charlson Comorbidity Index (±3). A comparative analysis was performed between the 2 organisms. The outcome includes responses at day 5 of peritonitis and the rate of complete response. Results There is a higher predilection of diabetes in those with S aureus peritonitis than in those with S lugdunensis (64.6% vs 31.6%; P = 0.03). Patients with S aureus peritonitis also have a much higher total cell count at presentation (4,463.9 ± 5,479.5 vs 1,807.9 ± 3,322.7; P = 0.05); a higher prevalence of poor response at day 5 (50.0% vs 15.8%; P = 0.03); a lower rate of complete response (64.6% vs 94.7%; P = 0.01) and are more prone to relapse with the same organism (29.2% vs 0%, respectively; P = 0.01) as compared to those with S lugdunensis. Limitations The result of this small retrospective study involving a single center may not be generalizable to other centers. There is also no data for comparative analysis on other coagulase-negative staphylococci such as Staphylococcus epidermidis, which belongs to the same family as S lugdunensis. Conclusions Although S aureus peritonitis is more virulent with significant morbidity, S lugdunensis can cause similarly serious peritonitis. This largest case series of S lugdunensis peritonitis enabled better characterization of clinical features and outcomes of patients with S lugdunensis peritonitis.
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Affiliation(s)
- Winston W.S. Fung
- Department of Medicine & Therapeutics, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China
| | - Ryan K.-H. SZE
- Department of Microbiology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China
| | - Cheuk-Chun Szeto
- Department of Medicine & Therapeutics, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China
- Li Ka Shing Institute of Health Sciences (LiHS), The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Kai-Ming Chow
- Department of Medicine & Therapeutics, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China
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Ravaioli S, Campoccia D, Mirzaei R, Mariani V, Bottau G, De Donno A, Montanaro L, Speziale P, Arciola CR. Searching for Virulence Factors among Staphylococcus lugdunensis Isolates from Orthopedic Infections: Correlation of β-hemolysin, hemolysin III, and slush Genes with Hemolytic Activity and Synergistic Hemolytic Activity. Int J Mol Sci 2023; 24:15724. [PMID: 37958706 PMCID: PMC10650139 DOI: 10.3390/ijms242115724] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/20/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
Staphylococcus lugdunensis is an emerging high-virulent pathogen. Here, the presence and expression of virulence genes (icaA, fbl, vwbl, fbpA, slush A, B and C, and genes of the putative β-hemolysin and hemolysin III) and the ability to induce synergistic hemolytic activity and hemolysis after 24, 48 and 72 h were investigated in a collection of twenty-two S. lugdunensis clinical isolates. The collection of isolates, mainly from implant orthopedic infections, had previously been grouped by ribotyping/dendrogram analysis and studied for biofilm matrices, biomasses and antibiotic resistances. Two isolates, constituting a unique small ribogroup sharing the same cluster, exhibited an amplicon size of the slush operon (S. lugdunensis synergistic hemolysin) which was shorter than the expected 977 bp. This outcome can predict the genetic lineage of the S. lugdunensis strains. One isolate (cra1342) presented two deletions: one of 90 bp in slush A and the other of 91 bp in slush B. Another isolate (N860314) showed a single 193 bp deletion, which encompassed part of the slush B terminal sequence and most of slush C. The isolate N860314 was devoid of hemolytic activity after 24 h, and the first consideration was that the deleted region deals with the coding of the active enzymatic site of the slush hemolysin. On the other hand, cra1342 and N860314 isolates with different slush deletions and with hemolytic activity after 24 and 48 h, respectively, could have replaced the hemolytic phenotype through other processes.
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Affiliation(s)
- Stefano Ravaioli
- Laboratorio di Patologia delle Infezioni Associate all’Impianto, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (D.C.); (V.M.); (G.B.); (A.D.D.); (L.M.)
| | - Davide Campoccia
- Laboratorio di Patologia delle Infezioni Associate all’Impianto, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (D.C.); (V.M.); (G.B.); (A.D.D.); (L.M.)
| | - Rasoul Mirzaei
- Venom and Biotherapeutics Molecules Laboratory, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran 1316943551, Iran;
| | - Valentina Mariani
- Laboratorio di Patologia delle Infezioni Associate all’Impianto, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (D.C.); (V.M.); (G.B.); (A.D.D.); (L.M.)
| | - Giulia Bottau
- Laboratorio di Patologia delle Infezioni Associate all’Impianto, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (D.C.); (V.M.); (G.B.); (A.D.D.); (L.M.)
| | - Andrea De Donno
- Laboratorio di Patologia delle Infezioni Associate all’Impianto, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (D.C.); (V.M.); (G.B.); (A.D.D.); (L.M.)
| | - Lucio Montanaro
- Laboratorio di Patologia delle Infezioni Associate all’Impianto, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (D.C.); (V.M.); (G.B.); (A.D.D.); (L.M.)
- Laboratory of Immunorheumatology and Tissue Regeneration, Laboratory of Pathology of Implant Infections, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy
| | - Pietro Speziale
- Department of Molecular Medicine, Biochemistry Section, Viale Taramelli 3/b, 27100 Pavia, Italy;
| | - Carla Renata Arciola
- Laboratory of Immunorheumatology and Tissue Regeneration, Laboratory of Pathology of Implant Infections, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Via San Giacomo 14, 40126 Bologna, Italy
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Ariëns RAS, Cassat JE. Surviving a sticky situation: therapeutic administration of fibrinogen variant γ' improves outcomes of Staphylococcus aureus septicemia. J Thromb Haemost 2023; 21:2048-2050. [PMID: 37468174 PMCID: PMC10947783 DOI: 10.1016/j.jtha.2023.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 07/21/2023]
Affiliation(s)
- Robert A S Ariëns
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - James E Cassat
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, USA.
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6
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Negrón O, Weggeman M, Grimbergen J, Clark EG, Abrahams S, Hur WS, Koopman J, Flick MJ. Fibrinogen γ' promotes host survival during Staphylococcus aureus septicemia in mice. J Thromb Haemost 2023; 21:2277-2290. [PMID: 37001817 PMCID: PMC10528022 DOI: 10.1016/j.jtha.2023.03.019] [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: 02/09/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/31/2023]
Abstract
BACKGROUND Staphylococcus aureus is a common gram-positive bacterium that is the causative agent for several human diseases, including sepsis. A key virulence mechanism is pathogen binding to host fibrinogen through the C-terminal region of the γ-chain. Previous work demonstrated that FggΔ5 mice expressing mutant fibrinogen γΔ5 lacking a S. aureus binding motif had significantly improved survival following S. aureus septicemia. Fibrinogen γ' is a human splice variant that represents about 10% to 15% of the total fibrinogen in plasma and circulates as a fibrinogen γ'-γ heterodimer (phFibγ'-γ). The fibrinogen γ'-chain is also expected to lack S. aureus binding function. OBJECTIVE Determine if human fibrinogen γ'-γ confers host protection during S. aureus septicemia. METHODS Analyses of survival and the host response following S. aureus septicemia challenge in FggΔ5 mice and mice reconstituted with purified phFibγ'-γ or phFibγ-γ. RESULTS Reconstitution of fibrinogen-deficient or wildtype mice with purified phFibγ'-γ prior to infection provided a significant prolongation in host survival relative to mice reconstituted with purified phFibγ-γ, which was superior to that observed with heterozygous FggΔ5 mice. Improved survival could not be accounted for by quantitative differences in fibrinogen-dependent adhesion or clumping, but phFibγ'-γ-containing mixtures generated notably smaller bacterial aggregates. Importantly, administration of phFibγ'-γ after infection also provided a therapeutic benefit by prolonging host survival relative to administration of phFibγ-γ. CONCLUSION These findings provide the proof-of-concept that changing the ratio of naturally occurring fibrinogen variants in blood could offer significant therapeutic potential against bacterial infection and potentially other diseases.
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Affiliation(s)
- Oscar Negrón
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | | | | | - Emily G Clark
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sara Abrahams
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Woosuk S Hur
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | | | - Matthew J Flick
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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7
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Wang C, Paiva TO, Motta C, Speziale P, Pietrocola G, Dufrêne YF. Catch Bond-Mediated Adhesion Drives Staphylococcus aureus Host Cell Invasion. NANO LETTERS 2023. [PMID: 37267288 DOI: 10.1021/acs.nanolett.3c01387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Various viruses and pathogenic bacteria interact with annexin A2 to invade mammalian cells. Here, we show that Staphylococcus aureus engages in extremely strong catch bonds for host cell invasion. By means of single-molecule atomic force microscopy, we find that bacterial surface-located clumping factors bind annexin A2 with extraordinary strength, indicating that these bonds are extremely resilient to mechanical tension. By determining the lifetimes of the complexes under increasing mechanical stress, we demonstrate that the adhesins form catch bonds with their ligand that are capable to sustain forces of 1500-1700 pN. The force-dependent adhesion mechanism identified here provides a molecular framework to explain how S. aureus pathogens tightly attach to host cells during invasion and shows promise for the design of new therapeutics against intracellular S. aureus.
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Affiliation(s)
- Can Wang
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Telmo O Paiva
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Chiara Motta
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Viale Taramelli 3/b, 27100 Pavia, Italy
| | - Pietro Speziale
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Viale Taramelli 3/b, 27100 Pavia, Italy
| | - Giampiero Pietrocola
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Viale Taramelli 3/b, 27100 Pavia, Italy
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
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Yan X, Xu Y, Shen C, Chen D. Inactivation of Staphylococcus aureus by Levulinic Acid Plus Sodium Dodecyl Sulfate and their Antibacterial Mechanisms on S. aureus Biofilms by Transcriptomic Analysis. J Food Prot 2023; 86:100050. [PMID: 36916557 DOI: 10.1016/j.jfp.2023.100050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/14/2023] [Accepted: 01/18/2023] [Indexed: 01/27/2023]
Abstract
The combination of levulinic acid (LVA) and sodium dodecyl sulfate (SDS) in recent years has shown a considerable potential to use as an antimicrobial intervention. The objectives of this study were to evaluate the antimicrobial efficacy of the combination against Staphylococcus aureus in both planktonic and biofilm states and to investigate the transcriptional changes in S. aureus biofilms coincubated with sublethal concentrations of LVA and/or SDS. The minimum inhibitory concentrations (MICs) of LVA and SDS determined by the microdilution method were 3.125 and 0.039 mg/mL, respectively. An additive bacteriostatic interaction (fractional inhibitory concentration index = 1) between the two compounds was observed by the checkerboard assay, whereas a synergistic bactericidal activity was displayed by the time-kill assay. The biomass and viable cells in the biofilms were reduced by both antimicrobials either alone or in combination in a dose-dependent manner. Transcriptomics indicated that more differentially expressed (DE) genes were observed in the biofilm treated with SDS (103 up- and 205 downregulated DE genes) and LVA + SDS (187 up and 162 down) than that coincubated with LVA (34 up and 32 down). The SDS and LVA + SDS treatments mainly affected the expression of genes responsible for cell surface proteins, virulence factors, adhesins, and capsular polysaccharides. Both the antibiofilm assay and the transcriptomics indicated that SDS, not LVA, was the major chemical contributing to the antibacterial efficacy of the combination. This study reveals the behavioral responses and protective mechanisms of S. aureus to LVA and SDS applied individually or in combination.
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Affiliation(s)
- Xiaoxue Yan
- College of Food Science, Southwest University, 2 Tiansheng Rd, Beibei, Chongqing 400715, China; Chongqing Key Laboratory of Speciality Food Co-Built by Sichuan and Chongqing, 400715, China
| | - Yiwei Xu
- College of Food Science, Southwest University, 2 Tiansheng Rd, Beibei, Chongqing 400715, China; Chongqing Key Laboratory of Speciality Food Co-Built by Sichuan and Chongqing, 400715, China
| | - Cangliang Shen
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV 26506, USA
| | - Dong Chen
- College of Food Science, Southwest University, 2 Tiansheng Rd, Beibei, Chongqing 400715, China; Chongqing Key Laboratory of Speciality Food Co-Built by Sichuan and Chongqing, 400715, China.
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9
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Staphylococcus lugdunensis. Trends Microbiol 2021; 29:1143-1145. [PMID: 34462188 DOI: 10.1016/j.tim.2021.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/27/2021] [Accepted: 07/29/2021] [Indexed: 11/23/2022]
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10
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Millar EV, Bennett JW, Barin B, Carey PM, Law NN, English CE, Schwartz MM, Cochrane T, Ellis MW, Tribble DR, Timothy Cooke M, Hennessey JP. Safety, immunogenicity, and efficacy of NDV-3A against Staphylococcus aureus colonization: A phase 2 vaccine trial among US Army Infantry trainees. Vaccine 2021; 39:3179-3188. [PMID: 33962841 PMCID: PMC10430023 DOI: 10.1016/j.vaccine.2021.04.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND Military trainees are at increased risk for Staphylococcus aureus colonization and infection. Disease prevention strategies are needed, but a S. aureus vaccine does not currently exist. METHODS We enrolled US Army Infantry trainees (Fort Benning, GA) in a phase 2, randomized, double-blind, placebo-controlled trial of NDV-3A, a vaccine containing a recombinant adhesin/invasion protein of Candida albicans that has structural similarity to the S. aureus protein clumping factor A. Study participants received one intramuscular dose of NDV-3A or placebo (adjuvant alone) within 72 h of arrival on base. Longitudinal nasal and oral (throat) swabs were collected throughout the 14-week Infantry training cycle. Safety, immunogenicity, and efficacy of NDV-3A against S. aureus nasal / oral acquisition were the endpoints. RESULTS The NDV-3A candidate had minimal reactogenicity and elicited robust antigen-specific B- and T-cell responses. During the 56-day post-vaccination period, there was no difference in the incidence of S. aureus nasal acquisition between those who were randomized to receive NDV-3A vs. placebo (25.6% vs. 29.1%; vaccine efficacy [VE]: 12.1%; p = 0.31). In time-to-event analysis, there was no difference between study groups with respect to the S. aureus colonization-free interval (VE: 13%; p = 0.29). Similarly, the efficacy of NDV-3A against S. aureus oral acquisition was poor (VE: 2.4%; p = 0.52). CONCLUSIONS A single dose of NDV-3A did not prevent nasal nor oral acquisition of S. aureus in a population of military trainees at high risk for colonization.
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Affiliation(s)
- Eugene V Millar
- Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States.
| | - Jason W Bennett
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Burc Barin
- The Emmes Company, Rockville, MD, United States
| | - Patrick M Carey
- Benning Martin Army Community Hospital, Fort Benning, GA, United States
| | - Natasha N Law
- Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States; Benning Martin Army Community Hospital, Fort Benning, GA, United States
| | - Caroline E English
- Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | | | | | - Michael W Ellis
- University of Toledo Medical Center, Toledo, OH, United States
| | - David R Tribble
- Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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Prasad JM, Negrón O, Du X, Mullins ES, Palumbo JS, Gilbertie JM, Höök M, Grover SP, Pawlinski R, Mackman N, Degen JL, Flick MJ. Host fibrinogen drives antimicrobial function in Staphylococcus aureus peritonitis through bacterial-mediated prothrombin activation. Proc Natl Acad Sci U S A 2021; 118:e2009837118. [PMID: 33443167 PMCID: PMC7817220 DOI: 10.1073/pnas.2009837118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The blood-clotting protein fibrinogen has been implicated in host defense following Staphylococcus aureus infection, but precise mechanisms of host protection and pathogen clearance remain undefined. Peritonitis caused by staphylococci species is a complication for patients with cirrhosis, indwelling catheters, or undergoing peritoneal dialysis. Here, we sought to characterize possible mechanisms of fibrin(ogen)-mediated antimicrobial responses. Wild-type (WT) (Fib+) mice rapidly cleared S. aureus following intraperitoneal infection with elimination of ∼99% of an initial inoculum within 15 min. In contrast, fibrinogen-deficient (Fib-) mice failed to clear the microbe. The genotype-dependent disparity in early clearance resulted in a significant difference in host mortality whereby Fib+ mice uniformly survived whereas Fib- mice exhibited high mortality rates within 24 h. Fibrin(ogen)-mediated bacterial clearance was dependent on (pro)thrombin procoagulant function, supporting a suspected role for fibrin polymerization in this mechanism. Unexpectedly, the primary host initiator of coagulation, tissue factor, was found to be dispensable for this antimicrobial activity. Rather, the bacteria-derived prothrombin activator vWbp was identified as the source of the thrombin-generating potential underlying fibrin(ogen)-dependent bacterial clearance. Mice failed to eliminate S. aureus deficient in vWbp, but clearance of these same microbes in WT mice was restored if active thrombin was administered to the peritoneal cavity. These studies establish that the thrombin/fibrinogen axis is fundamental to host antimicrobial defense, offer a possible explanation for the clinical observation that coagulase-negative staphylococci are a highly prominent infectious agent in peritonitis, and suggest caution against anticoagulants in individuals susceptible to peritoneal infections.
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Affiliation(s)
- Joni M Prasad
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Oscar Negrón
- Department of Pathology and Laboratory Medicine, Lineberger Comprehensive Cancer Center, and the UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599
| | - Xinli Du
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Eric S Mullins
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Joseph S Palumbo
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Jessica M Gilbertie
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606
| | - Magnus Höök
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technologies, Texas A&M Health Sciences Center, Houston, TX 77030
| | - Steven P Grover
- Department of Medicine, Lineberger Comprehensive Cancer Center, and the UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599
| | - Rafal Pawlinski
- Department of Medicine, Lineberger Comprehensive Cancer Center, and the UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599
| | - Nigel Mackman
- Department of Medicine, Lineberger Comprehensive Cancer Center, and the UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599
| | - Jay L Degen
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Matthew J Flick
- Department of Pathology and Laboratory Medicine, Lineberger Comprehensive Cancer Center, and the UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599;
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12
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Staphylococcus lugdunensis: a Skin Commensal with Invasive Pathogenic Potential. Clin Microbiol Rev 2020; 34:34/2/e00205-20. [PMID: 33361142 DOI: 10.1128/cmr.00205-20] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Staphylococcus lugdunensis is a species of coagulase-negative staphylococcus (CoNS) that causes serious infections in humans akin to those of S. aureus It was often misidentified as S. aureus, but this has been rectified by recent routine use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) in diagnostic laboratories. It encodes a diverse array of virulence factors for adhesion, cytotoxicity, and innate immune evasion, but these are less diverse than those encoded by S. aureus It expresses an iron-regulated surface determinant (Isd) system combined with a novel energy-coupling factor (ECF) mechanism for extracting heme from hemoproteins. Small cytolytic S. lugdunensis synergistic hemolysins (SLUSH), peptides related to phenol-soluble modulins of S. aureus, act synergistically with β-toxin to lyse erythrocytes. S. lugdunensis expresses a novel peptide antibiotic, lugdunin, that can influence the nasal and skin microbiota. Endovascular infections are initiated by bacterial adherence to fibrinogen promoted by a homologue of Staphylococcus aureus clumping factor A and to von Willebrand factor on damaged endothelium by an uncharacterized mechanism. S. lugdunensis survives within mature phagolysosomes of macrophages without growing and is released only following apoptosis. This differs fundamentally from S. aureus, which actively grows and expresses bicomponent leukotoxins that cause membrane damage and could contribute to survival in the infected host. S. lugdunensis is being investigated as a probiotic to eradicate S. aureus from the nares of carriers. However, this is contraindicated by its innate virulence. Studies to obtain a deeper understanding of S. lugdunensis colonization, virulence, and microbiome interactions are therefore warranted.
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13
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Pickering AC, Fitzgerald JR. The Role of Gram-Positive Surface Proteins in Bacterial Niche- and Host-Specialization. Front Microbiol 2020; 11:594737. [PMID: 33193271 PMCID: PMC7658395 DOI: 10.3389/fmicb.2020.594737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/05/2020] [Indexed: 11/25/2022] Open
Abstract
Gram-positive bacterial pathogens have an array of proteins on their cell surface that mediate interactions with the host environment. In particular, bacterial cell wall-associated (CWA) proteins play key roles in both colonization and pathogenesis. Furthermore, some CWA proteins promote specialization for host-species or mediate colonization of specific anatomical niches within a host. In this mini review, we provide examples of the many ways by which major pathogens, such as Staphylococci, Streptococci and Listeria monocytogenes, utilize CWA proteins for both host- and niche-specialization. We describe different biological mechanisms mediated by CWA proteins including: the acquisition of iron from hemoglobin in the bloodstream, adherence to and invasion of host cells, and innate immune evasion through binding to the plasma proteins fibrinogen, immunoglobulin G, and complement. We also discuss the limitations of using animal models for understanding the role of specific CWA proteins in host-specialization and how transformative technologies, such as CRISPR-Cas, offer tremendous potential for developing transgenic models that simulate the host environment of interest. Improved understanding of the role of CWA proteins in niche- or host-specificity will allow the design of new therapeutic approaches which target key host–pathogen interactions underpinning Gram-positive bacterial infections.
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Affiliation(s)
- Amy C Pickering
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, United Kingdom
| | - J Ross Fitzgerald
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, United Kingdom
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14
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Schilcher K, Horswill AR. Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020; 84:e00026-19. [PMID: 32792334 PMCID: PMC7430342 DOI: 10.1128/mmbr.00026-19] [Citation(s) in RCA: 302] [Impact Index Per Article: 75.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
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Affiliation(s)
- Katrin Schilcher
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA
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15
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Schilcher K, Horswill AR. Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020. [PMID: 32792334 DOI: 10.1128/mmbr.00026-19/asset/e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
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Affiliation(s)
- Katrin Schilcher
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA
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16
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Pietrocola G, Pellegrini A, Alfeo MJ, Marchese L, Foster TJ, Speziale P. The iron-regulated surface determinant B (IsdB) protein from Staphylococcus aureus acts as a receptor for the host protein vitronectin. J Biol Chem 2020; 295:10008-10022. [PMID: 32499371 DOI: 10.1074/jbc.ra120.013510] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/01/2020] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus aureus is an important bacterial pathogen that can cause a wide spectrum of diseases in humans and other animals. S. aureus expresses a variety of virulence factors that promote infection with this pathogen. These include cell-surface proteins that mediate adherence of the bacterial cells to host extracellular matrix components, such as fibronectin and fibrinogen. Here, using immunoblotting, ELISA, and surface plasmon resonance analysis, we report that the iron-regulated surface determinant B (IsdB) protein, besides being involved in heme transport, plays a novel role as a receptor for the plasma and extracellular matrix protein vitronectin (Vn). Vn-binding activity was expressed by staphylococcal strains grown under iron starvation conditions when Isd proteins are expressed. Recombinant IsdB bound Vn dose dependently and specifically. Both near-iron transporter motifs NEAT1 and NEAT2 of IsdB individually bound Vn in a saturable manner, with KD values in the range of 16-18 nm Binding of Vn to IsdB was specifically blocked by heparin and reduced at high ionic strength. Furthermore, IsdB-expressing bacterial cells bound significantly higher amounts of Vn from human plasma than did an isdB mutant. Adherence to and invasion of epithelial and endothelial cells by IsdB-expressing S. aureus cells was promoted by Vn, and an αvβ3 integrin-blocking mAb or cilengitide inhibited adherence and invasion by staphylococci, suggesting that Vn acts as a bridge between IsdB and host αvβ3 integrin.
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Affiliation(s)
- Giampiero Pietrocola
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Angelica Pellegrini
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Mariangela J Alfeo
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Loredana Marchese
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Timothy J Foster
- Department of Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Pietro Speziale
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
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17
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The MSCRAMM Family of Cell-Wall-Anchored Surface Proteins of Gram-Positive Cocci. Trends Microbiol 2019; 27:927-941. [PMID: 31375310 DOI: 10.1016/j.tim.2019.06.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/10/2019] [Accepted: 06/19/2019] [Indexed: 01/21/2023]
Abstract
The microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) are a family of proteins that are defined by the presence of two adjacent IgG-like folded subdomains. These promote binding to ligands by mechanisms that involve major conformational changes exemplified by the binding to fibrinogen by the 'dock-lock-latch' mechanism or to collagen by the 'collagen hug'. Clumping factors A and B are two such MSCRAMMs that have several important roles in the pathogenesis of Staphylococcus aureus infections. MSCRAMM architecture, ligand binding, and roles in infection and colonization are examined with a focus on recent developments with clumping factors.
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18
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Pickering AC, Vitry P, Prystopiuk V, Garcia B, Höök M, Schoenebeck J, Geoghegan JA, Dufrêne YF, Fitzgerald JR. Host-specialized fibrinogen-binding by a bacterial surface protein promotes biofilm formation and innate immune evasion. PLoS Pathog 2019; 15:e1007816. [PMID: 31216354 PMCID: PMC6602291 DOI: 10.1371/journal.ppat.1007816] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/01/2019] [Accepted: 05/06/2019] [Indexed: 11/18/2022] Open
Abstract
Fibrinogen is an essential part of the blood coagulation cascade and a major component of the extracellular matrix in mammals. The interface between fibrinogen and bacterial pathogens is an important determinant of the outcome of infection. Here, we demonstrate that a canine host-restricted skin pathogen, Staphylococcus pseudintermedius, produces a cell wall-associated protein (SpsL) that has evolved the capacity for high strength binding to canine fibrinogen, with reduced binding to fibrinogen of other mammalian species including humans. Binding occurs via the surface-expressed N2N3 subdomains, of the SpsL A-domain, to multiple sites in the fibrinogen α-chain C-domain by a mechanism analogous to the classical dock, lock, and latch binding model. Host-specific binding is dependent on a tandem repeat region of the fibrinogen α-chain, a region highly divergent between mammals. Of note, we discovered that the tandem repeat region is also polymorphic in different canine breeds suggesting a potential influence on canine host susceptibility to S. pseudintermedius infection. Importantly, the strong host-specific fibrinogen-binding interaction of SpsL to canine fibrinogen is essential for bacterial aggregation and biofilm formation, and promotes resistance to neutrophil phagocytosis, suggesting a key role for the interaction during pathogenesis. Taken together, we have dissected a bacterial surface protein-ligand interaction resulting from the co-evolution of host and pathogen that promotes host-specific innate immune evasion and may contribute to its host-restricted ecology. Many bacterial pathogens are specialized for a single host-species and rarely cause infections of other hosts. Our understanding of the bacterial factors underpinning host-specificity are limited. Here we demonstrate that a canine host-restricted bacterial pathogen, Staphylococcus pseudintermedius, produces a surface protein (SpsL) that has the ability to preferentially bind to canine fibrinogen with high strength. This host-specific interaction has evolved via binding to a tandem repeat region of the fibrinogen α-chain which is divergent among mammalian species. Importantly, we found that the strong binding interaction with canine fibrinogen promotes bacterial aggregation and biofilm formation as well as inhibiting neutrophil phagocytosis. Our findings reveal the host-adaptive evolution of a key bacterium-host interaction that promotes evasion of the host immune response.
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Affiliation(s)
- Amy C. Pickering
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, United Kingdom
| | - Pauline Vitry
- Institute of Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Valeriia Prystopiuk
- Institute of Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Brandon Garcia
- Department of Microbiology and Immunology, Brody school of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Magnus Höök
- Center for Infectious and Inflammatory Diseases, Texas A&M Health Science Center, Houston, Texas, United States of America
| | - Jeffrey Schoenebeck
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, United Kingdom
| | - Joan A. Geoghegan
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Yves F. Dufrêne
- Institute of Life Sciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- Walloon Excellence in Life Sciences and Biotechnology, Wavre, Belgium
| | - J. Ross Fitzgerald
- The Roslin Institute and Edinburgh Infectious Diseases, University of Edinburgh, Easter Bush Campus, Edinburgh, Scotland, United Kingdom
- * E-mail:
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19
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Clumping factor B is an important virulence factor during Staphylococcus aureus skin infection and a promising vaccine target. PLoS Pathog 2019; 15:e1007713. [PMID: 31009507 PMCID: PMC6497315 DOI: 10.1371/journal.ppat.1007713] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 05/02/2019] [Accepted: 03/19/2019] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus aureus expresses a number of cell wall-anchored proteins that mediate adhesion and invasion of host cells and tissues and promote immune evasion, consequently contributing to the virulence of this organism. The cell wall-anchored protein clumping factor B (ClfB) has previously been shown to facilitate S. aureus nasal colonization through high affinity interactions with the cornified envelope in the anterior nares. However, the role of ClfB during skin and soft tissue infection (SSTI) has never been investigated. This study reveals a novel role for ClfB during SSTIs. ClfB is crucial in determining the abscess structure and bacterial burden early in infection and this is dependent upon a specific interaction with the ligand loricrin which is expressed within the abscess tissue. Targeting ClfB using a model vaccine that induced both protective humoral and cellular responses, leads to protection during S. aureus skin infection. This study therefore identifies ClfB as an important antigen for future SSTI vaccines. Staphylococcus aureus is the leading cause of skin and soft tissue infections (SSTIs), the treatment of which is becoming increasingly difficult due to antibiotic resistance. An anti-S. aureus vaccine offers a potential solution, but a better understanding of how S. aureus causes pathology during SSTI is required to identify effective vaccine targets. Here, we identify an important virulence determinant during S. aureus SSTI. Clumping factor B (ClfB), a surface protein expressed by S. aureus is shown to promote skin abscess formation by binding to the host protein loricrin. Targeting ClfB using a model vaccine conferred significant protection during S. aureus SSTI. In this study, we uncover an entirely novel mechanism by which S. aureus forms abscesses during skin infection, identifying an important therapeutic target for treating S. aureus SSTI.
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20
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Staphylococcus aureus clumping factor A is a force-sensitive molecular switch that activates bacterial adhesion. Proc Natl Acad Sci U S A 2018; 115:5564-5569. [PMID: 29735708 PMCID: PMC6003445 DOI: 10.1073/pnas.1718104115] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The Staphylococcus aureus surface protein clumping factor A (ClfA) binds to the blood plasma protein fibrinogen (Fg) via molecular interactions that are poorly understood. Here, we unravel the forces guiding the interaction between ClfA and immobilized Fg, showing that it is dramatically enhanced by tensile loading. Our findings favor a model whereby ClfA interacts with Fg via two distinct binding sites, the adhesive function of which is tightly regulated by mechanical force. Reminiscent of a catch bond mechanism, this force-enhanced adhesion explains the ability of ClfA to promote S. aureus colonization of host tissues and biomedical devices under physical stress. Clumping factor A (ClfA), a cell-wall–anchored protein from Staphylococcus aureus, is a virulence factor in various infections and facilitates the colonization of protein-coated biomaterials. ClfA promotes bacterial adhesion to the blood plasma protein fibrinogen (Fg) via molecular forces that have not been studied so far. A unique, yet poorly understood, feature of ClfA is its ability to favor adhesion to Fg at high shear stress. Unraveling the strength and dynamics of the ClfA–Fg interaction would help us better understand how S. aureus colonizes implanted devices and withstands physiological shear stress. By means of single-molecule experiments, we show that ClfA behaves as a force-sensitive molecular switch that potentiates staphylococcal adhesion under mechanical stress. The bond between ClfA and immobilized Fg is weak (∼0.1 nN) at low tensile force, but is dramatically enhanced (∼1.5 nN) by mechanical tension, as observed with catch bonds. Strong bonds, but not weak ones, are inhibited by a peptide mimicking the C-terminal segment of the Fg γ-chain. These results point to a model whereby ClfA interacts with Fg via two distinct binding sites, the adhesive function of which is regulated by mechanical tension. This force-activated mechanism is of biological significance because it explains at the molecular level the ability of ClfA to promote bacterial attachment under high physiological shear stress.
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21
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The Staphylococcus aureus Cell Wall-Anchored Protein Clumping Factor A Is an Important T Cell Antigen. Infect Immun 2017; 85:IAI.00549-17. [PMID: 28947645 PMCID: PMC5695125 DOI: 10.1128/iai.00549-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/18/2017] [Indexed: 02/06/2023] Open
Abstract
Staphylococcus aureus has become increasingly resistant to antibiotics, and vaccines offer a potential solution to this epidemic of antimicrobial resistance. Targeting of specific T cell subsets is now considered crucial for next-generation anti-S. aureus vaccines; however, there is a paucity of information regarding T cell antigens of S. aureus. This study highlights the importance of cell wall-anchored proteins as human CD4+ T cell activators capable of driving antigen-specific Th1 and Th17 cell activation. Clumping factor A (ClfA), which contains N1, N2, and N3 binding domains, was found to be a potent human T cell activator. We further investigated which subdomains of ClfA were involved in T cell activation and found that the full-length ClfA N123 and N23 were potent Th1 and Th17 activators. Interestingly, the N1 subdomain was capable of exclusively activating Th1 cells. Furthermore, when these subdomains were used in a model vaccine, N23 and N1 offered Th1- and Th17-mediated systemic protection in mice upon intraperitoneal challenge. Overall, however, full-length ClfA N123 is required for maximal protection both locally and systemically.
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22
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Mohamad M, Uçkay I, Hannouche D, Miozzari H. Particularities of Staphylococcus Lugdunensis in orthopaedic infections. Infect Dis (Lond) 2017; 50:223-225. [PMID: 28937308 DOI: 10.1080/23744235.2017.1374553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Morad Mohamad
- a Orthopaedic Surgery Service , Geneva University Hospitals , Geneva , Switzerland
| | - Ilker Uçkay
- a Orthopaedic Surgery Service , Geneva University Hospitals , Geneva , Switzerland.,b Faculty of Medicine, University of Geneva , Geneva , Switzerland
| | - Didier Hannouche
- a Orthopaedic Surgery Service , Geneva University Hospitals , Geneva , Switzerland
| | - Hermès Miozzari
- a Orthopaedic Surgery Service , Geneva University Hospitals , Geneva , Switzerland
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Abstract
The staphylococci comprise a diverse genus of Gram-positive, nonmotile commensal organisms that inhabit the skin and mucous membranes of humans and other mammals. In general, staphylococci are benign members of the natural flora, but many species have the capacity to be opportunistic pathogens, mainly infecting individuals who have medical device implants or are otherwise immunocompromised. Staphylococcus aureus and Staphylococcus epidermidis are major sources of hospital-acquired infections and are the most common causes of surgical site infections and medical device-associated bloodstream infections. The ability of staphylococci to form biofilms in vivo makes them highly resistant to chemotherapeutics and leads to chronic diseases. These biofilm infections include osteomyelitis, endocarditis, medical device infections, and persistence in the cystic fibrosis lung. Here, we provide a comprehensive analysis of our current understanding of staphylococcal biofilm formation, with an emphasis on adhesins and regulation, while also addressing how staphylococcal biofilms interact with the immune system. On the whole, this review will provide a thorough picture of biofilm formation of the staphylococcus genus and how this mode of growth impacts the host.
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Naudin C, Schumski A, Salo-Ahen OMH, Herwald H, Smeds E. A rapid method for selecting suitable animal species for studying pathogen interactions with plasma protein ligands in vivo. Microb Biotechnol 2017; 10:657-665. [PMID: 28168836 PMCID: PMC5404189 DOI: 10.1111/1751-7915.12601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 12/15/2016] [Indexed: 12/01/2022] Open
Abstract
Species tropism constitutes a serious problem for developing relevant animal models of infection. Human pathogens can express virulence factors that show specific selectivity to human proteins, while their affinity for orthologs from other species can vary significantly. Suitable animal species must be used to analyse whether virulence factors are potential targets for drug development. We developed an assay that rapidly predicts applicable animal species for studying virulence factors binding plasma proteins. We used two well‐characterized Staphylococcus aureus proteins, SSL7 and Efb, to develop an ELISA‐based inhibition assay using plasma from different animal species. The interaction between SSL7 and human C5 and the binding of Efb to human fibrinogen and human C3 was studied. Affinity experiments and Western blot analyses were used to validate the assay. Human, monkey and cat plasma interfered with binding of SSL7 to human C5. Binding of Efb to human fibrinogen was blocked in human, monkey, gerbil and pig plasma, while human, monkey, gerbil, rabbit, cat and guinea pig plasma inhibited the binding of Efb to human C3. These results emphasize the importance of choosing correct animal models, and thus, our approach is a rapid and cost‐effective method that can be used to prevent unnecessary animal experiments.
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Affiliation(s)
- Clément Naudin
- Department of Clinical Sciences Lund, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Ariane Schumski
- Department of Clinical Sciences Lund, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Outi M H Salo-Ahen
- Faculty of Natural Sciences and Engineering, Pharmacy, Åbo Akademi University, Turku, Finland
| | - Heiko Herwald
- Department of Clinical Sciences Lund, Division of Infection Medicine, Lund University, Lund, Sweden
| | - Emanuel Smeds
- Department of Clinical Sciences Lund, Division of Infection Medicine, Lund University, Lund, Sweden
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Yu W, Kim HK, Rauch S, Schneewind O, Missiakas D. Pathogenic conversion of coagulase-negative staphylococci. Microbes Infect 2017; 19:101-109. [PMID: 28012900 PMCID: PMC5274588 DOI: 10.1016/j.micinf.2016.12.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 12/02/2016] [Accepted: 12/14/2016] [Indexed: 12/31/2022]
Abstract
Humans and animals are colonized by members of the genus Staphylococcus, however only some of these species evolved to cause invasive disease. The genetic basis for conversion of commensal staphylococci into pathogens is not known. We hypothesized that Staphylococcus aureus genes for coagulation and agglutination in vertebrate blood (coa, vwb and clfA) may support pathogenic conversion. Expression of coa and vwb in Staphylococcus epidermidis or Staphylococcus simulans supported a coagulase-positive phenotype but not the ability to cause disease in a mouse model of bloodstream infection. However, the simultaneous expression of coa, vwb and clfA in coagulase-negative staphylococci enabled bacterial agglutination in plasma and enhanced survival of S. simulans in human whole blood. Agglutination of S. simulans in the bloodstream of infected mice upon expression of coa, vwb and clfA provided also a mean for dissemination and replication in distal organs. Thus, the acquisition of genes for bacterial agglutination with fibrin appear sufficient for the conversion of commensal staphylococci into invasive pathogens.
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Affiliation(s)
- Wenqi Yu
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Hwan Keun Kim
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Sabine Rauch
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, IL, USA
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26
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Ganesh VK, Liang X, Geoghegan JA, Cohen ALV, Venugopalan N, Foster TJ, Hook M. Lessons from the Crystal Structure of the S. aureus Surface Protein Clumping Factor A in Complex With Tefibazumab, an Inhibiting Monoclonal Antibody. EBioMedicine 2016; 13:328-338. [PMID: 27789272 PMCID: PMC5264652 DOI: 10.1016/j.ebiom.2016.09.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 09/13/2016] [Accepted: 09/29/2016] [Indexed: 01/07/2023] Open
Abstract
The Staphylococcus aureus fibrinogen binding MSCRAMM (Microbial Surface Components Recognizing Adhesive Matrix Molecules), ClfA (clumping factor A) is an important virulence factor in staphylococcal infections and a component of several vaccines currently under clinical evaluation. The mouse monoclonal antibody aurexis (also called 12-9), and the humanized version tefibazumab are therapeutic monoclonal antibodies targeting ClfA that in combination with conventional antibiotics were effective in animal models but showed less impressive efficacy in a limited Phase II clinical trial. We here report the crystal structure and a biochemical characterization of the ClfA/tefibazumab (Fab) complex. The epitope for tefibazumab is located to the "top" of the N3 subdomain of ClfA and partially overlaps with a previously unidentified second binding site for fibrinogen. A high-affinity binding of ClfA to fibrinogen involves both an interaction at the N3 site and the previously identified docking of the C-terminal segment of the fibrinogen γ-chain in the N2N3 trench. Although tefibazumab binds ClfA with high affinity we observe a modest IC50 value for the inhibition of fibrinogen binding to the MSCRAMM. This observation, paired with a common natural occurring variant of ClfA that is not effectively recognized by the mAb, may partly explain the modest effect tefibazumab showed in the initial clinic trail. This information will provide guidance for the design of the next generation of therapeutic anti-staphylococcal mAbs targeting ClfA.
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Affiliation(s)
- Vannakambadi K. Ganesh
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A & M University Health Science Center, 2121 W Holcombe Blvd., Houston, TX 77030, USA,Corresponding authors.
| | - Xiaowen Liang
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A & M University Health Science Center, 2121 W Holcombe Blvd., Houston, TX 77030, USA
| | - Joan A. Geoghegan
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Ana Luisa V. Cohen
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A & M University Health Science Center, 2121 W Holcombe Blvd., Houston, TX 77030, USA
| | - Nagarajan Venugopalan
- GM/CA@APS, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439, USA
| | - Timothy J Foster
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Magnus Hook
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A & M University Health Science Center, 2121 W Holcombe Blvd., Houston, TX 77030, USA,Corresponding authors.
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27
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Foster TJ. The remarkably multifunctional fibronectin binding proteins of Staphylococcus aureus. Eur J Clin Microbiol Infect Dis 2016; 35:1923-1931. [PMID: 27604831 DOI: 10.1007/s10096-016-2763-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 08/16/2016] [Indexed: 12/01/2022]
Abstract
Staphylococcus aureus expresses two distinct but closely related multifunctional cell wall-anchored (CWA) proteins that bind to the host glycoprotein fibronectin. The fibronectin binding proteins FnBPA and FnBPB comprise two distinct domains. The C-terminal domain comprises a tandem array of repeats that bind to the N-terminal type I modules of fibronectin by the tandem β-zipper mechanism. This causes allosteric activation of a cryptic integrin binding domain, allowing fibronectin to act as a bridge between bacterial cells and the α5β1 integrin on host cells, triggering bacterial uptake by endocytosis. Variants of FnBPA with polymorphisms in fibronectin binding repeats (FnBRs) that increase affinity for the ligand are associated with strains that infect cardiac devices and cause endocarditis, suggesting that binding affinity is particularly important in intravascular infections. The N-terminal A domains of FnBPA and FnBPB have diverged into seven antigenically distinct isoforms. Each binds fibrinogen by the 'dock, lock and latch' mechanism characteristic of clumping factor A. However, FnBPs can also bind to elastin, which is probably important in adhesion to connective tissue in vivo. In addition, they can capture plasminogen from plasma, which can be activated to plasmin by host and bacterial plasminogen activators. The bacterial cells become armed with a host protease which destroys opsonins, contributing to immune evasion and promotes spreading during skin infection. Finally, some methicillin-resistant S. aureus (MRSA) strains form biofilm that depends on the elaboration of FnBPs rather than polysaccharide. The A domains of the FnBPs can interact homophilically, allowing cells to bind together as the biofilm accumulates.
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Affiliation(s)
- T J Foster
- Microbiology Department, Trinity College, Dublin 2, Ireland.
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28
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Crosby HA, Kwiecinski J, Horswill AR. Staphylococcus aureus Aggregation and Coagulation Mechanisms, and Their Function in Host-Pathogen Interactions. ADVANCES IN APPLIED MICROBIOLOGY 2016; 96:1-41. [PMID: 27565579 DOI: 10.1016/bs.aambs.2016.07.018] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The human commensal bacterium Staphylococcus aureus can cause a wide range of infections ranging from skin and soft tissue infections to invasive diseases like septicemia, endocarditis, and pneumonia. Muticellular organization almost certainly contributes to S. aureus pathogenesis mechanisms. While there has been considerable focus on biofilm formation and its role in colonizing prosthetic joints and indwelling devices, less attention has been paid to nonsurface-attached group behavior like aggregation and clumping. S. aureus is unique in its ability to coagulate blood, and it also produces multiple fibrinogen-binding proteins that facilitate clumping. Formation of clumps, which are large, tightly packed groups of cells held together by fibrin(ogen), has been demonstrated to be important for S. aureus virulence and immune evasion. Clumps of cells are able to avoid detection by the host's immune system due to a fibrin(ogen) coat that acts as a shield, and the size of the clumps facilitates evasion of phagocytosis. In addition, clumping could be an important early step in establishing infections that involve tight clusters of cells embedded in host matrix proteins, such as soft tissue abscesses and endocarditis. In this review, we discuss clumping mechanisms and regulation, as well as what is known about how clumping contributes to immune evasion.
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Affiliation(s)
- H A Crosby
- University of Iowa, Iowa City, IA, United States
| | - J Kwiecinski
- University of Iowa, Iowa City, IA, United States
| | - A R Horswill
- University of Iowa, Iowa City, IA, United States
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Staphylococcus aureus Clumping Factor A Remains a Viable Vaccine Target for Prevention of S. aureus Infection. mBio 2016; 7:e00225. [PMID: 26956591 PMCID: PMC4810491 DOI: 10.1128/mbio.00225-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
In a recent article, X. Li et al. [mBio 7(1):e02232-15, 2016, http://dx.doi.org/10.1128/mBio.02232-15] investigate the utility of a vaccine composed of the Staphylococcus aureus protein clumping factor A (ClfA) in protecting mice from S. aureus infection. ClfA, one of the first proteins to be identified as a potential vaccine antigen for S. aureus prophylaxis, is currently a component of several investigational vaccines. The authors conclude that ClfA may not be effective for S. aureus prophylaxis. In contrast, previously published papers reporting positive data suggested that ClfA was potentially an important vaccine target to prevent invasive S. aureus disease. This commentary addresses the observed differences between the findings of Li et al. and those from other publications, highlighting the importance for preclinical vaccine antigen assessments to reflect the biological role of said antigen in virulence and, consequently, the importance of choosing appropriate preclinical disease models to test such antigens.
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30
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Staphylococcus chromogenes, a Coagulase-Negative Staphylococcus Species That Can Clot Plasma. J Clin Microbiol 2016; 54:1372-5. [PMID: 26912749 DOI: 10.1128/jcm.03139-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 02/13/2016] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus chromogenes is one of the main coagulase-negative staphylococci isolated from mastitis of dairy cows. We describe S. chromogenes isolates that can clot plasma. Since the main pathogen causing mastitis is coagulase-positive Staphylococcus aureus, the coagulase-positive phenotype of S. chromogenes described here can easily lead to misidentification.
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31
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Brown AF, Murphy AG, Lalor SJ, Leech JM, O’Keeffe KM, Mac Aogáin M, O’Halloran DP, Lacey KA, Tavakol M, Hearnden CH, Fitzgerald-Hughes D, Humphreys H, Fennell JP, van Wamel WJ, Foster TJ, Geoghegan JA, Lavelle EC, Rogers TR, McLoughlin RM. Memory Th1 Cells Are Protective in Invasive Staphylococcus aureus Infection. PLoS Pathog 2015; 11:e1005226. [PMID: 26539822 PMCID: PMC4634925 DOI: 10.1371/journal.ppat.1005226] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 09/23/2015] [Indexed: 12/15/2022] Open
Abstract
Mechanisms of protective immunity to Staphylococcus aureus infection in humans remain elusive. While the importance of cellular immunity has been shown in mice, T cell responses in humans have not been characterised. Using a murine model of recurrent S. aureus peritonitis, we demonstrated that prior exposure to S. aureus enhanced IFNγ responses upon subsequent infection, while adoptive transfer of S. aureus antigen-specific Th1 cells was protective in naïve mice. Translating these findings, we found that S. aureus antigen-specific Th1 cells were also significantly expanded during human S. aureus bloodstream infection (BSI). These Th1 cells were CD45RO+, indicative of a memory phenotype. Thus, exposure to S. aureus induces memory Th1 cells in mice and humans, identifying Th1 cells as potential S. aureus vaccine targets. Consequently, we developed a model vaccine comprising staphylococcal clumping factor A, which we demonstrate to be an effective human T cell antigen, combined with the Th1-driving adjuvant CpG. This novel Th1-inducing vaccine conferred significant protection during S. aureus infection in mice. This study notably advances our understanding of S. aureus cellular immunity, and demonstrates for the first time that a correlate of S. aureus protective immunity identified in mice may be relevant in humans. Staphylococcus aureus is a leading cause of skin, soft tissue and bone infections and, most seriously, bloodstream infection. When S. aureus does get into the bloodstream, it is more likely to kill than any other bacterial infection, despite all the treatments modern medicine has to offer. It has thus far developed resistance to all antibiotics licensed to treat it. Thus, there is an urgent need to develop a vaccine against S. aureus. However, such a vaccine remains elusive. This is largely due to the fact that we have a very limited understanding of how our immune system fights this infection. Here, we examine how certain T cells of the mouse immune system effectively recognise and respond to S. aureus, and show that transferring these cells to other mice improves their ability to clear infection. We then demonstrate that a vaccine which drives these specific T cells also improves clearance of infection. Until recently, it was not known if human T cells could recognise and respond to S. aureus. Here we show, for the first time, that these cells are expanded in patients with S. aureus bloodstream infection, and suggest that they should be targeted in anti-S. aureus vaccines.
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Affiliation(s)
- Aisling F. Brown
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Alison G. Murphy
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Stephen J. Lalor
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - John M. Leech
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Kate M. O’Keeffe
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Micheál Mac Aogáin
- Department of Clinical Microbiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Dara P. O’Halloran
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Keenan A. Lacey
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Mehri Tavakol
- Department of Medical Microbiology & Infectious Diseases, Erasmus Medical Center, Rotterdam, Netherlands
| | - Claire H. Hearnden
- Adjuvant Research Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | | | - Hilary Humphreys
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Dublin, Ireland
- Department of Microbiology, Beaumont Hospital, Dublin, Ireland
| | - Jérôme P. Fennell
- Department of Clinical Microbiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
- Department of Clinical Microbiology, Adelaide Meath & National Children’s Hospital, Dublin, Ireland
| | - Willem J. van Wamel
- Department of Medical Microbiology & Infectious Diseases, Erasmus Medical Center, Rotterdam, Netherlands
| | - Timothy J. Foster
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Joan A. Geoghegan
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Ed C. Lavelle
- Adjuvant Research Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
- Advanced Materials and Bioengineering Research Centre (AMBER), Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland
| | - Thomas R. Rogers
- Department of Clinical Microbiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
- Department of Clinical Microbiology, St. James's Hospital, Dublin, Ireland
| | - Rachel M. McLoughlin
- Host-Pathogen Interactions Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
- * E-mail:
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32
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Mice expressing a mutant form of fibrinogen that cannot support fibrin formation exhibit compromised antimicrobial host defense. Blood 2015; 126:2047-58. [PMID: 26228483 DOI: 10.1182/blood-2015-04-639849] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/26/2015] [Indexed: 12/14/2022] Open
Abstract
Fibrin(ogen) is central to hemostasis and thrombosis and also contributes to multiple physiologic and pathologic processes beyond coagulation. However, the precise contribution of soluble fibrinogen vs insoluble fibrin matrices to vascular integrity, tissue repair, inflammation, and disease has been undefined and unapproachable. To establish the means to distinguish fibrinogen- and fibrin-dependent processes in vivo, Fib(AEK) mice were generated that carry normal levels of circulating fibrinogen but lack the capacity for fibrin polymer formation due to a germ-line mutation in the Aα chain thrombin cleavage site. Homozygous Fib(AEK) mice developed to term and exhibited postnatal survival superior to that of fibrinogen-deficient mice. Unlike fibrinogen-deficient mice, platelet-rich plasma from Fib(AEK) mice supported normal platelet aggregation in vitro, highlighting that fibrinogen(AEK) retains the functional capacity to support interactions with platelets. Thrombin failed to release fibrinopeptide-A from fibrinogen(AEK) and failed to induce polymer formation with Fib(AEK) plasma or purified fibrinogen(AEK) in 37°C mixtures regardless of incubation time. Fib(AEK) mice displayed both an absence of fibrin polymer formation following liver injury, as assessed by electron microscopy, and a failure to generate stable occlusive thrombi following FeCl3 injury of carotid arteries. Fib(AEK) mice exhibited a profound impediment in Staphylococcus aureus clearance following intraperitoneal infection similar to fibrinogen-deficient mice, yet Fib(AEK) mice displayed a significant infection dose-dependent survival advantage over fibrinogen-deficient mice following peritonitis challenge. Collectively, these findings establish for the first time that fibrin polymer is the molecular form critical for antimicrobial mechanisms while simultaneously highlighting biologically meaningful contributions and functions of the soluble molecule.
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Zapotoczna M, McCarthy H, Rudkin JK, O'Gara JP, O'Neill E. An Essential Role for Coagulase in Staphylococcus aureus Biofilm Development Reveals New Therapeutic Possibilities for Device-Related Infections. J Infect Dis 2015; 212:1883-93. [PMID: 26044292 DOI: 10.1093/infdis/jiv319] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 05/30/2015] [Indexed: 12/15/2022] Open
Abstract
High-level resistance to antimicrobial drugs is a major factor in the pathogenesis of chronic Staphylococcus aureus biofilm-associated, medical device-related infections. Antimicrobial susceptibility analysis revealed that biofilms grown for ≤ 24 hours on biomaterials conditioned with human plasma under venous shear in iron-free cell culture medium were significantly more susceptible to antistaphylococcal antibiotics. Biofilms formed under these physiologically relevant conditions were regulated by SaeRS and dependent on coagulase-catalyzed conversion of fibrinogen into fibrin. In contrast, SarA-regulated biofilms formed on uncoated polystyrene in nutrient-rich bacteriological medium were mediated by the previously characterized biofilm factors poly-N-acetyl glucosamine, fibronectin-binding proteins, or autolytic activity and were antibiotic resistant. Coagulase-mediated biofilms exhibited increased antimicrobial resistance over time (>48 hours) but were always susceptible to dispersal by the fibrinolytic enzymes plasmin or nattokinase. Biofilms recovered from infected central venous catheters in a rat model of device-related infection were dispersed by nattokinase, supporting the important role of the biofilm phenotype and identifying a potentially new therapeutic approach with antimicrobials and fibrinolytic drugs, particularly during the early stages of device-related infection.
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Affiliation(s)
- Marta Zapotoczna
- Department of Clinical Microbiology, Education and Research Centre, Beaumont Hospital, Royal College of Surgeons in Ireland
| | - Hannah McCarthy
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Justine K Rudkin
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - James P O'Gara
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Eoghan O'Neill
- Department of Clinical Microbiology, Education and Research Centre, Beaumont Hospital, Royal College of Surgeons in Ireland Department of Microbiology, Connolly Hospital, Dublin
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Salazar N, Castiblanco-Valencia MM, da Silva LB, de Castro ÍA, Monaris D, Masuda HP, Barbosa AS, Arêas APM. Staphylococcus aureus manganese transport protein C (MntC) is an extracellular matrix- and plasminogen-binding protein. PLoS One 2014; 9:e112730. [PMID: 25409527 PMCID: PMC4237344 DOI: 10.1371/journal.pone.0112730] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 10/14/2014] [Indexed: 11/18/2022] Open
Abstract
Infections caused by Staphylococcus aureus – particularly nosocomial infections - represent a great concern. Usually, the early stage of pathogenesis consists on asymptomatic nasopharynx colonization, which could result in dissemination to other mucosal niches or invasion of sterile sites, such as blood. This pathogenic route depends on scavenging of nutrients as well as binding to and disrupting extracellular matrix (ECM). Manganese transport protein C (MntC), a conserved manganese-binding protein, takes part in this infectious scenario as an ion-scavenging factor and surprisingly as an ECM and coagulation cascade binding protein, as revealed in this work. This study showed a marked ability of MntC to bind to several ECM and coagulation cascade components, including laminin, collagen type IV, cellular and plasma fibronectin, plasminogen and fibrinogen by ELISA. The MntC binding to plasminogen appears to be related to the presence of surface-exposed lysines, since previous incubation with an analogue of lysine residue, ε-aminocaproic acid, or increasing ionic strength affected the interaction between MntC and plasminogen. MntC-bound plasminogen was converted to active plasmin in the presence of urokinase plasminogen activator (uPA). The newly released plasmin, in turn, acted in the cleavage of the α and β chains of fibrinogen. In conclusion, we describe a novel function for MntC that may help staphylococcal mucosal colonization and establishment of invasive disease, through the interaction with ECM and coagulation cascade host proteins. These data suggest that this potential virulence factor could be an adequate candidate to compose an anti-staphylococcal human vaccine formulation.
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Affiliation(s)
- Natália Salazar
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABCSanto André, Brazil
| | | | | | - Íris Arantes de Castro
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Denize Monaris
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Hana Paula Masuda
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABCSanto André, Brazil
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Multi-virulence-locus sequence typing of Staphylococcus lugdunensis generates results consistent with a clonal population structure and is reliable for epidemiological typing. J Clin Microbiol 2014; 52:3624-32. [PMID: 25078912 DOI: 10.1128/jcm.01370-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Staphylococcus lugdunensis is an emergent virulent coagulase-negative staphylococcus responsible for severe infections similar to those caused by Staphylococcus aureus. To understand its potentially pathogenic capacity and have further detailed knowledge of the molecular traits of this organism, 93 isolates from various geographic origins were analyzed by multi-virulence-locus sequence typing (MVLST), targeting seven known or putative virulence-associated loci (atlLR2, atlLR3, hlb, isdJ, SLUG_09050, SLUG_16930, and vwbl). The polymorphisms of the putative virulence-associated loci were moderate and comparable to those of the housekeeping genes analyzed by multilocus sequence typing (MLST). However, the MVLST scheme generated 43 virulence types (VTs) compared to 20 sequence types (STs) based on MLST, indicating that MVLST was significantly more discriminating (Simpson's index [D], 0.943). No hypervirulent lineage or cluster specific to carriage strains was defined. The results of multilocus sequence analysis of known and putative virulence-associated loci are consistent with a clonal population structure for S. lugdunensis, suggesting a coevolution of these genes with housekeeping genes. Indeed, the nonsynonymous to synonymous evolutionary substitutions (dN/dS) ratio, the Tajima's D test, and Single-likelihood ancestor counting (SLAC) analysis suggest that all virulence-associated loci were under negative selection, even atlLR2 (AtlL protein) and SLUG_16930 (FbpA homologue), for which the dN/dS ratios were higher. In addition, this analysis of virulence-associated loci allowed us to propose a trilocus sequence typing scheme based on the intragenic regions of atlLR3, isdJ, and SLUG_16930, which is more discriminant than MLST for studying short-term epidemiology and further characterizing the lineages of the rare but highly pathogenic S. lugdunensis.
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36
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Herman P, El-Kirat-Chatel S, Beaussart A, Geoghegan JA, Foster TJ, Dufrêne YF. The binding force of the staphylococcal adhesin SdrG is remarkably strong. Mol Microbiol 2014; 93:356-68. [PMID: 24898289 DOI: 10.1111/mmi.12663] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2014] [Indexed: 11/27/2022]
Abstract
SdrG is a cell surface adhesin from Staphylococcus epidermidis which binds to the blood plasma protein fibrinogen (Fg). Ligand binding follows a 'dock, lock and latch' model involving dynamic conformational changes of the adhesin that result in a greatly stabilized adhesin-ligand complex. To date, the force and dynamics of this multistep interaction are poorly understood. Here we use atomic force microscopy (AFM) to unravel the binding strength and cell surface localization of SdrG at molecular resolution. Single-cell force spectroscopy shows that SdrG mediates time-dependent attachment to Fg-coated surfaces. Single-molecule force spectroscopy with Fg-coated AFM tips demonstrates that the adhesin forms nanoscale domains on the cell surface, which we believe contribute to strengthen cell adhesion. Notably, we find that the rupture force of single SdrG-Fg bonds is very large, ∼ 2 nN, equivalent to the strength of a covalent bond, and shows a low dissociation rate, suggesting that the bond is very stable. The strong binding force, slow dissociation and clustering of SdrG provide a molecular foundation for the ability of S. epidermidis to colonize implanted biomaterials and to withstand physiological shear forces.
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Affiliation(s)
- Philippe Herman
- Université catholique de Louvain, Institute of Life Sciences, Croix du Sud, 1, bte L7.04.01., B-1348, Louvain-la-Neuve, Belgium
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Solis N, Parker BL, Kwong SM, Robinson G, Firth N, Cordwell SJ. Staphylococcus aureus surface proteins involved in adaptation to oxacillin identified using a novel cell shaving approach. J Proteome Res 2014; 13:2954-72. [PMID: 24708102 DOI: 10.1021/pr500107p] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Staphylococcus aureus is a Gram-positive pathogen responsible for a variety of infections, and some strains are resistant to virtually all classes of antibiotics. Cell shaving proteomics using a novel probability scoring algorithm to compare the surfaceomes of the methicillin-resistant, laboratory-adapted S. aureus COL strain with a COL strain in vitro adapted to high levels of oxacillin (APT). APT displayed altered cell morphology compared with COL and increased aggregation in biofilm assays. Increased resistance to β-lactam antibiotics was observed, but adaptation to oxacillin did not confer multidrug resistance. Analysis of the S. aureus COL and APT surfaceomes identified 150 proteins at a threshold determined by the scoring algorithm. Proteins unique to APT included the LytR-CpsA-Psr (LCP) domain-containing MsrR and SACOL2302. Quantitative RT-PCR showed increased expression of sacol2302 in APT grown with oxacillin (>6-fold compared with COL). Overexpression of sacol2302 in COL to levels consistent with APT (+ oxacillin) did not influence biofilm formation or β-lactam resistance. Proteomics using iTRAQ and LC-MS/MS identified 1323 proteins (∼50% of the theoretical S. aureus proteome), and cluster analysis demonstrated elevated APT abundances of LCP proteins, capsule and peptidoglycan biosynthesis proteins, and proteins involved in wall remodelling. Adaptation to oxacillin also induced urease proteins, which maintained culture pH compared to COL. These results show that S. aureus modifies surface architecture in response to antibiotic adaptation.
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Affiliation(s)
- Nestor Solis
- School of Molecular Bioscience, ‡Discipline of Pathology, School of Medical Sciences, and §School of Biological Sciences, The University of Sydney , New South Wales 2006, Australia
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IsdC from Staphylococcus lugdunensis induces biofilm formation under low-iron growth conditions. Infect Immun 2014; 82:2448-59. [PMID: 24686057 DOI: 10.1128/iai.01542-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Staphylococcus lugdunensis is a coagulase-negative staphylococcus that is a commensal of humans and an opportunistic pathogen. It can cause a spectrum of infections, including those that are associated with the ability to form biofilm, such as occurs with endocarditis or indwelling medical devices. The genome sequences of two strains revealed the presence of orthologues of the ica genes that are responsible for synthesis of poly-N-acetylglucosamine (PNAG) that is commonly associated with biofilm in other staphylococci. However, we discovered that biofilm formed by a panel of S. lugdunensis isolates growing in iron-restricted medium was susceptible to degradation by proteases and not by metaperiodate, suggesting that the biofilm matrix comprised proteins and not PNAG. When the iron concentration was raised to 1 mM biofilm formation by all strains tested was greatly reduced. A mutant of strain N920143 lacking the entire locus that encodes iron-regulated surface determinant (Isd) proteins was defective in biofilm formation under iron-limited conditions. An IsdC-null mutant was defective, whereas IsdK, IsdJ, and IsdB mutants formed biofilm to the same level as the parental strain. Expression of IsdC was required both for the primary attachment to unconditioned polystyrene and for the accumulation phase of biofilm involving cell-cell interactions. Purified recombinant IsdC protein formed dimers in solution and Lactococcus lactis cells expressing only IsdC adhered to immobilized recombinant IsdC but not to IsdJ, IsdK, or IsdB. This is consistent with a specific homophilic interaction between IsdC molecules on neighboring cells contributing to accumulation of S. lugdunensis biofilm in vivo.
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Thomer L, Becker S, Emolo C, Quach A, Kim HK, Rauch S, Anderson M, Leblanc JF, Schneewind O, Faull KF, Missiakas D. N-acetylglucosaminylation of serine-aspartate repeat proteins promotes Staphylococcus aureus bloodstream infection. J Biol Chem 2013; 289:3478-86. [PMID: 24344128 DOI: 10.1074/jbc.m113.532655] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Staphylococcus aureus secretes products that convert host fibrinogen to fibrin and promote its agglutination with fibrin fibrils, thereby shielding bacteria from immune defenses. The agglutination reaction involves ClfA (clumping factor A), a surface protein with serine-aspartate (SD) repeats that captures fibrin fibrils and fibrinogen. Pathogenic staphylococci express several different SD proteins that are modified by two glycosyltransferases, SdgA and SdgB. Here, we characterized three genes of S. aureus, aggA, aggB (sdgA), and aggC (sdgB), and show that aggA and aggC contribute to staphylococcal agglutination with fibrin fibrils in human plasma. We demonstrate that aggB (sdgA) and aggC (sdgB) are involved in GlcNAc modification of the ClfA SD repeats. However, only sdgB is essential for GlcNAc modification, and an sdgB mutant is defective in the pathogenesis of sepsis in mice. Thus, GlcNAc modification of proteins promotes S. aureus replication in the bloodstream of mammalian hosts.
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Affiliation(s)
- Lena Thomer
- From the Department of Microbiology, The University of Chicago, Chicago, Illinois 60637 and
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Seo HS, Minasov G, Seepersaud R, Doran KS, Dubrovska I, Shuvalova L, Anderson WF, Iverson TM, Sullam PM. Characterization of fibrinogen binding by glycoproteins Srr1 and Srr2 of Streptococcus agalactiae. J Biol Chem 2013; 288:35982-96. [PMID: 24165132 PMCID: PMC3861647 DOI: 10.1074/jbc.m113.513358] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serine-rich repeat glycoproteins of Gram-positive bacteria comprise a large family of cell wall proteins. Streptococcus agalactiae (group B streptococcus, GBS) expresses either Srr1 or Srr2 on its surface, depending on the strain. Srr1 has recently been shown to bind fibrinogen, and this interaction contributes to the pathogenesis of GBS meningitis. Although strains expressing Srr2 appear to be hypervirulent, no ligand for this adhesin has been described. We now demonstrate that Srr2 also binds human fibrinogen and that this interaction promotes GBS attachment to endothelial cells. Recombinant Srr1 and Srr2 bound fibrinogen in vitro, with affinities of KD = 2.1 × 10−5 and 3.7 × 10−6m, respectively, as measured by surface plasmon resonance spectroscopy. The binding site for Srr1 and Srr2 was localized to tandem repeats 6–8 of the fibrinogen Aα chain. The structures of both the Srr1 and Srr2 binding regions were determined and, in combination with mutagenesis studies, suggest that both Srr1 and Srr2 interact with a segment of these repeats via a “dock, lock, and latch” mechanism. Moreover, properties of the latch region may account for the increased affinity between Srr2 and fibrinogen. Together, these studies identify how greater affinity of Srr2 for fibrinogen may contribute to the increased virulence associated with Srr2-expressing strains.
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Affiliation(s)
- Ho Seong Seo
- From the Division of Infectious Diseases, Veterans Affairs Medical Center, University of California at San Francisco and the Northern California Institute for Research and Education, San Francisco, California 94121
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Heilbronner S, Hanses F, Monk IR, Speziale P, Foster TJ. Sortase A promotes virulence in experimental Staphylococcus lugdunensis endocarditis. Microbiology (Reading) 2013; 159:2141-2152. [DOI: 10.1099/mic.0.070292-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Simon Heilbronner
- Department of Microbiology, School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Frank Hanses
- Department of Internal Medicine I, University Hospital Regensburg, Germany
| | - Ian R. Monk
- Department of Microbiology, School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Pietro Speziale
- Department of Molecular Medicine, Section of Biochemistry, Viale Taramelli 3/b, Pavia 27100, Italy
| | - Timothy J. Foster
- Department of Microbiology, School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
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Pietrocola G, Geoghegan JA, Rindi S, Di Poto A, Missineo A, Consalvi V, Foster TJ, Speziale P. Molecular Characterization of the Multiple Interactions of SpsD, a Surface Protein from Staphylococcus pseudintermedius, with Host Extracellular Matrix Proteins. PLoS One 2013; 8:e66901. [PMID: 23805283 PMCID: PMC3689669 DOI: 10.1371/journal.pone.0066901] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 05/12/2013] [Indexed: 12/03/2022] Open
Abstract
Staphylococcus pseudintermedius, a commensal and pathogen of dogs and occasionally of humans, expresses surface proteins potentially involved in host colonization and pathogenesis. Here, we describe the cloning and characterization of SpsD, a surface protein of S. pseudintermedius reported as interacting with extracellular matrix proteins and corneocytes. A ligand screen and Western immunoblotting revealed that the N-terminal A domain of SpsD bound fibrinogen, fibronectin, elastin and cytokeratin 10. SpsD also interfered with thrombin-induced fibrinogen coagulation and blocked ADP-induced platelet aggregation. The binding site for SpsD was mapped to residues 395–411 in the fibrinogen γ-chain, while binding sites in fibronectin were localized to the N- and C-terminal regions. SpsD also bound to glycine- and serine-rich omega loops within the C-terminal tail region of cytokeratin 10. Ligand binding studies using SpsD variants lacking the C-terminal segment or containing an amino-acid substitution in the putative ligand binding site provided insights into interaction mechanism of SpsD with the different ligands. Together these data demonstrate the multi-ligand binding properties of SpsD and illustrate some interesting differences in the variety of ligands bound by SpsD and related proteins from S. aureus.
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Affiliation(s)
| | - Joan A. Geoghegan
- Department Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Simonetta Rindi
- Department of Molecular Medicine, Institute of Biochemistry, Pavia, Italy
| | - Antonella Di Poto
- Department of Molecular Medicine, Institute of Biochemistry, Pavia, Italy
| | - Antonino Missineo
- Department of Molecular Medicine, Institute of Biochemistry, Pavia, Italy
| | - Valerio Consalvi
- Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome “La Sapienza”, Roma, Italy
| | - Timothy J. Foster
- Department Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Pietro Speziale
- Department of Molecular Medicine, Institute of Biochemistry, Pavia, Italy
- * E-mail:
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Seo HS, Xiong YQ, Sullam PM. Role of the serine-rich surface glycoprotein Srr1 of Streptococcus agalactiae in the pathogenesis of infective endocarditis. PLoS One 2013; 8:e64204. [PMID: 23717569 PMCID: PMC3662765 DOI: 10.1371/journal.pone.0064204] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 04/12/2013] [Indexed: 11/26/2022] Open
Abstract
The binding of bacteria to fibrinogen and platelets are important events in the pathogenesis of infective endocarditis. Srr1 is a serine-rich repeat glycoprotein of Streptococcus agalactiae that binds directly to the Aα chain of human fibrinogen. To assess the impact of Srr1 on the pathogenesis of endocarditis due to S. agalactiae, we first examined the binding of this organism to immobilized human platelets. Strains expressing Srr1 had significantly higher levels of binding to human platelets in vitro, as compared with isogenic Δsrr1 mutants. In addition, platelet binding was inhibited by pretreatment with anti-fibrinogen IgG or purified Srr1 binding region. To assess the contribution of Srr1 to pathogenicity, we compared the relative virulence of S. agalactiae NCTC 10/84 strain and its Δsrr1 mutant in a rat model of endocarditis, where animals were co-infected with the WT and the mutant strains at a 1∶1 ratio. At 72 h post-infection, bacterial densities (CFU/g) of the WT strain within vegetations, kidneys, and spleens were significantly higher, as compared with the Δsrr1 mutant. These results indicate that Srr1 contributes to the pathogenesis of endocarditis due to S. agalactiae, at least in part through its role in fibrinogen-mediated platelet binding.
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Affiliation(s)
- Ho Seong Seo
- Division of Infectious Diseases, Veterans Affairs Medical Center and the University of California San Francisco, San Francisco, California, United States of America
| | - Yan Q. Xiong
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
- Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Paul M. Sullam
- Division of Infectious Diseases, Veterans Affairs Medical Center and the University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Subdomains N2N3 of fibronectin binding protein A mediate Staphylococcus aureus biofilm formation and adherence to fibrinogen using distinct mechanisms. J Bacteriol 2013; 195:2675-83. [PMID: 23564165 DOI: 10.1128/jb.02128-12] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Health care-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) forms biofilm in vitro that is dependent on the surface-located fibronectin binding proteins A and B (FnBPA, FnBPB). Here we provide new insights into the requirements for FnBP-dependent biofilm formation by MRSA. We show that expression of FnBPs is sustained at high levels throughout the growth cycle in the HA-MRSA strain BH1CC in contrast to laboratory strain SH1000, where expression could be detected only in exponential phase. We found that FnBP-mediated biofilm accumulation required Zn(2+), while the removal of Zn(2+) had no effect on the ability of FnBPA to mediate bacterial adherence to fibrinogen. We also investigated the role of FnBPA expressed on the surface of S. aureus in promoting biofilm formation and bacterial adhesion to fibrinogen. The minimum part of FnBPA required for ligand binding has so far been defined only with recombinant proteins. Here we found that the N1 subdomain was not required for biofilm formation or for FnBPA to promote bacterial adherence to fibrinogen. Residues at the C terminus of subdomain N3 required for FnBPA to bind to ligands using the "dock, lock, and latch" mechanism were necessary for FnBPA to promote bacterial adherence to fibrinogen. However, these residues were not necessary to form biofilm, allowing us to localize the region of FnBPA required for biofilm accumulation to residues 166 to 498. Thus, FnBPA mediates biofilm formation and bacterial adhesion to fibrinogen using two distinct mechanisms. Finally, we identified a hitherto-unrecognized thrombin cleavage site close to the boundary between subdomains N1 and N2 of FnBPA.
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Genetic elimination of the binding motif on fibrinogen for the S. aureus virulence factor ClfA improves host survival in septicemia. Blood 2013; 121:1783-94. [PMID: 23299312 DOI: 10.1182/blood-2012-09-453894] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Fibrinogen can support host antimicrobial containment/clearance mechanisms, yet selected pathogens appear to benefit from host procoagulants to drive bacterial virulence. Here, we explored the hypothesis that host fibrin(ogen), on balance, supports Staphylococcus aureus infection in the context of septicemia. Survival studies following intravenous infection in control and fibrinogen-deficient mice established the overall utility of host fibrin(ogen) to S. aureus virulence. Complementary studies in mice expressing mutant forms of fibrinogen-retaining clotting function, but lacking either the bacterial ClfA (Fibγ(Δ5)) binding motif or the host leukocyte integrin receptor αMβ2 (Fibγ(390-396A)) binding motif, revealed the preeminent importance of the bacterial ClfA-fibrin(ogen) interaction in determining host survival. Studies of mice lacking platelets or the platelet integrin receptor subunit αIIb established that the survival benefits observed in Fibγ(Δ5) mice were largely independent of platelet αIIbβ3-mediated engagement of fibrinogen. Fibγ(Δ5) mice exhibited reduced bacterial burdens in the hearts and kidneys, a blunted host proinflammatory cytokine response, diminished microscopic tissue damage, and significantly diminished plasma markers of cardiac and other organ damage. These findings indicate that host fibrin(ogen) and bacterial ClfA are dual determinants of virulence and that therapeutic interventions at the level of fibrinogen could be advantageous in S. aureus septicemia.
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Staphylococcus Lugdunensis, An Aggressive Coagulase-Negative Pathogen not to be Underestimated. Int J Artif Organs 2012; 35:742-53. [DOI: 10.5301/ijao.5000142] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2012] [Indexed: 01/06/2023]
Abstract
The new emerging coagulase-negative pathogen Staphylococcus lugdunensis is responsible for severe cardiac and joint infections. Since the biochemical phenotypic systems designed for the identification of CoNS do not appear to be species specific and are hardly reliable for the discrimination of S. lugdunensis from other staphylococci, its precise identification requires fine molecular methods. The pathogenic mechanisms by which S. lugdunensis causes severe infections are not yet completely elucidated and in this review its virulence and toxic determinants are surveyed as well as its adhesins and biofilm production.
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Interactions of Staphylococci with Osteoblasts and Phagocytes in the Pathogenesis of Implant-Associated Osteomyelitis. Int J Artif Organs 2012; 35:713-26. [DOI: 10.5301/ijao.5000158] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2012] [Indexed: 11/20/2022]
Abstract
In spite of great advancements in the field of biomaterials and in surgical techniques, the implant of medical devices is still associated with a high risk of bacterial infection. Implant-associated osteomyelitis is a deep infection of bone around the implant. The continuous inflammatory destruction of bone tissues characterizes this serious bone infectious disease. Staphylococcus aureus and Staphylococcus epidermidis are the most prevalent etiologic agents of implant-associated infections, together with the emerging pathogen Staphylococcus lugdunensis. Various interactions between staphylococci, osteoblasts, and phagocytes occurring in the peri-prosthesis environment play a crucial role in the pathogenesis of implant-associated osteomyelitis. Here we focus on two main events: internalization of staphylococci into osteoblasts, and bacterial interactions with phagocytic cells.
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A recombinant clumping factor A-containing vaccine induces functional antibodies to Staphylococcus aureus that are not observed after natural exposure. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:1641-50. [PMID: 22896688 DOI: 10.1128/cvi.00354-12] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Staphylococcus aureus is a Gram-positive pathogen that causes devastating disease and whose pathogenesis is dependent on interactions with host cell factors. Staphylococcal clumping factor A (ClfA) is a highly conserved fibrinogen (Fg)-binding protein and virulence factor that contributes to host tissue adhesion and initiation of infection. ClfA is being investigated as a possible component of a staphylococcal vaccine. We report the development of an Fg-binding assay that is specific for ClfA-mediated binding. Using the assay, we show that despite the presence of anti-ClfA antibodies, human sera from unvaccinated subjects are unable to prevent the binding of S. aureus to an Fg-coated surface. In contrast, antibodies elicited by a recombinant ClfA-containing vaccine were capable of blocking the ClfA-dependent binding of a diverse and clinically relevant collection of staphylococcal strains to Fg. These functional antibodies were also able to displace S. aureus already bound to Fg, suggesting that the ligand-binding activity of ClfA can be effectively neutralized through vaccination.
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Xiang H, Feng Y, Wang J, Liu B, Chen Y, Liu L, Deng X, Yang M. Crystal structures reveal the multi-ligand binding mechanism of Staphylococcus aureus ClfB. PLoS Pathog 2012; 8:e1002751. [PMID: 22719251 PMCID: PMC3375286 DOI: 10.1371/journal.ppat.1002751] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 04/30/2012] [Indexed: 01/07/2023] Open
Abstract
Staphylococcus aureus (S. aureus) pathogenesis is a complex process involving a diverse array of extracellular and cell wall components. ClfB, an MSCRAMM (Microbial Surface Components Recognizing Adhesive Matrix Molecules) family surface protein, described as a fibrinogen-binding clumping factor, is a key determinant of S. aureus nasal colonization, but the molecular basis for ClfB-ligand recognition remains unknown. In this study, we solved the crystal structures of apo-ClfB and its complexes with fibrinogen α (Fg α) and cytokeratin 10 (CK10) peptides. Structural comparison revealed a conserved glycine-serine-rich (GSR) ClfB binding motif (GSSGXGXXG) within the ligands, which was also found in other human proteins such as Engrailed protein, TCF20 and Dermokine proteins. Interaction between Dermokine and ClfB was confirmed by subsequent binding assays. The crystal structure of ClfB complexed with a 15-residue peptide derived from Dermokine revealed the same peptide binding mode of ClfB as identified in the crystal structures of ClfB-Fg α and ClfB-CK10. The results presented here highlight the multi-ligand binding property of ClfB, which is very distinct from other characterized MSCRAMMs to-date. The adherence of multiple peptides carrying the GSR motif into the same pocket in ClfB is reminiscent of MHC molecules. Our results provide a template for the identification of other molecules targeted by S. aureus during its colonization and infection. We propose that other MSCRAMMs like ClfA and SdrG also possess multi-ligand binding properties.
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Affiliation(s)
- Hua Xiang
- Key Laboratory for Protein Sciences of Ministry of Education, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Department of Veterinary Pharmacology, College of Animal Science and Veterinary Medicine, Jilin University, Changchun, China
| | - Yue Feng
- Key Laboratory for Protein Sciences of Ministry of Education, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jiawei Wang
- Key Laboratory for Protein Sciences of Ministry of Education, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Bao Liu
- Department of Vascular Surgery, Peking Union Medical College Hospital, Beijing, China
| | - Yeguang Chen
- Key Laboratory for Protein Sciences of Ministry of Education, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lei Liu
- Key Laboratory for Protein Sciences of Ministry of Education, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Department of Chemistry, Tsinghua University, Beijing, China
| | - Xuming Deng
- Department of Veterinary Pharmacology, College of Animal Science and Veterinary Medicine, Jilin University, Changchun, China
- * E-mail: (XD); (MY)
| | - Maojun Yang
- Key Laboratory for Protein Sciences of Ministry of Education, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- * E-mail: (XD); (MY)
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50
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Ghai R, Falconer RJ, Collins BM. Applications of isothermal titration calorimetry in pure and applied research--survey of the literature from 2010. J Mol Recognit 2012; 25:32-52. [PMID: 22213449 DOI: 10.1002/jmr.1167] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Isothermal titration calorimetry (ITC) is a biophysical technique for measuring the formation and dissociation of molecular complexes and has become an invaluable tool in many branches of science from cell biology to food chemistry. By measuring the heat absorbed or released during bond formation, ITC provides accurate, rapid, and label-free measurement of the thermodynamics of molecular interactions. In this review, we survey the recent literature reporting the use of ITC and have highlighted a number of interesting studies that provide a flavour of the diverse systems to which ITC can be applied. These include measurements of protein-protein and protein-membrane interactions required for macromolecular assembly, analysis of enzyme kinetics, experimental validation of molecular dynamics simulations, and even in manufacturing applications such as food science. Some highlights include studies of the biological complex formed by Staphylococcus aureus enterotoxin C3 and the murine T-cell receptor, the mechanism of membrane association of the Parkinson's disease-associated protein α-synuclein, and the role of non-specific tannin-protein interactions in the quality of different beverages. Recent developments in automation are overcoming limitations on throughput imposed by previous manual procedures and promise to greatly extend usefulness of ITC in the future. We also attempt to impart some practical advice for getting the most out of ITC data for those researchers less familiar with the method.
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Affiliation(s)
- Rajesh Ghai
- Institute for Molecular Bioscience (IMB), University of Queensland, St. Lucia, Queensland, 4072, Australia
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