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Syndecan-1 Promotes Streptococcus pneumoniae Corneal Infection by Facilitating the Assembly of Adhesive Fibronectin Fibrils. mBio 2020; 11:mBio.01907-20. [PMID: 33293379 PMCID: PMC7733941 DOI: 10.1128/mbio.01907-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Subversion of heparan sulfate proteoglycans (HSPGs) is thought to be a common virulence mechanism shared by many microbial pathogens. The prevailing assumption is that pathogens co-opt HSPGs as cell surface attachment receptors or as inhibitors of innate host defense. However, there are few data that clearly support this idea in vivo We found that deletion of syndecan-1 (Sdc1), a major cell surface HSPG of epithelial cells, causes a gain of function in a mouse model of scarified corneal infection, where Sdc1-/- corneas were significantly less susceptible to Streptococcus pneumoniae infection. Administration of excess Sdc1 ectodomains significantly inhibited S. pneumoniae corneal infection, suggesting that Sdc1 promotes infection as a cell surface attachment receptor. However, S. pneumoniae did not interact with Sdc1 and Sdc1 was shed upon S. pneumoniae infection, indicating that Sdc1 does not directly support S. pneumoniae adhesion. Instead, Sdc1 promoted S. pneumoniae adhesion by driving the assembly of fibronectin (FN) fibrils in the corneal basement membrane to which S. pneumoniae attaches when infecting injured corneas. S. pneumoniae specifically bound to corneal FN via PavA, and PavA deletion significantly attenuated S. pneumoniae virulence in the cornea. Excess Sdc1 ectodomains inhibited S. pneumoniae corneal infection by binding to the Hep II domain and interfering with S. pneumoniae PavA binding to FN. These findings reveal a previously unknown virulence mechanism of S. pneumoniae where key extracellular matrix (ECM) interactions and structures that are essential for host cell homeostasis are exploited for bacterial pathogenesis.IMPORTANCE Bacterial pathogens have evolved several ingenious mechanisms to subvert host cell biology for their pathogenesis. Bacterial attachment to the host ECM establishes a niche to grow and is considered one of the critical steps of infection. This pathogenic mechanism entails coordinated assembly of the ECM by the host to form the ECM structure and organization that are specifically recognized by bacteria for their adhesion. We serendipitously discovered that epithelial Sdc1 facilitates the assembly of FN fibrils in the corneal basement membrane and that this normal biological function of Sdc1 has detrimental consequences for the host in S. pneumoniae corneal infection. Our studies suggest that bacterial subversion of the host ECM is more complex than previously appreciated.
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McNitt DH, Van De Water L, Marasco D, Berisio R, Lukomski S. Streptococcal Collagen-like Protein 1 Binds Wound Fibronectin: Implications in Pathogen Targeting. Curr Med Chem 2019; 26:1933-1945. [PMID: 30182848 DOI: 10.2174/0929867325666180831165704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/18/2018] [Accepted: 06/28/2018] [Indexed: 02/01/2023]
Abstract
Group A Streptococcus (GAS) infections are responsible for significant morbidity and mortality worldwide. The outlook for an effective global vaccine is reduced because of significant antigenic variation among GAS strains worldwide. Other challenges in GAS therapy include the lack of common access to antibiotics in developing countries, as well as allergy to and treatment failures with penicillin and increasing erythromycin resistance in the industrialized world. At the portal of entry, GAS binds to newly deposited extracellular matrix, which is rich in cellular fibronectin isoforms with extra domain A (EDA, also termed EIIIA) via the surface adhesin, the streptococcal collagen-like protein 1 (Scl1). Recombinant Scl1 constructs, derived from diverse GAS strains, bind the EDA loop segment situated between the C and C' β-strands. Despite the sequence diversity in Scl1 proteins, multiple sequence alignments and secondary structure predictions of Scl1 variants, as well as crystallography and homology modeling studies, point to a conserved mechanism of Scl1-EDA binding. We propose that targeting this interaction may prevent the progression of infection. A synthetic cyclic peptide, derived from the EDA C-C' loop, binds to recombinant Scl1 with a micromolar dissociation constant. This review highlights the current concept of EDA binding to Scl1 and provides incentives to exploit this binding to treat GAS infections and wound colonization.
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Affiliation(s)
- Dudley H McNitt
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University School of Medicine, 2095 Health Sciences North, Morgantown, WV 26506, United States
| | - Livingston Van De Water
- Departments of Surgery and Regenerative and Cancer Cell Biology, Albany Medical College, Albany, NY 12208, United States
| | - Daniela Marasco
- Department of Pharmacy, University of Naples Frederico II, Naples, Italy
| | - Rita Berisio
- Institute of Biostructures and Bioimaging, National Research Council, via Mezzocannone, 16, 80134, Naples, Italy
| | - Slawomir Lukomski
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University School of Medicine, 2095 Health Sciences North, Morgantown, WV 26506, United States
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Turner CE, Bubba L, Efstratiou A. Pathogenicity Factors in Group C and G Streptococci. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0020-2018. [PMID: 31111818 PMCID: PMC11026075 DOI: 10.1128/microbiolspec.gpp3-0020-2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Indexed: 11/20/2022] Open
Abstract
Initially recognized zoonoses, streptococci belonging to Lancefield group C (GCS) and G (GGS) were subsequently recognised as human pathogens causing a diverse range of symptoms, from asymptomatic carriage to life threatening diseases. Their taxonomy has changed during the last decade. Asymptomatic carriage is <4% amongst the human population and invasive infections are often in association with chronic diseases such as diabetes, cardiovascular diseases or chronic skin infections. Other clinical manifestations include acute pharyngitis, pneumonia, endocarditis, bacteraemia and toxic-shock syndrome. Post streptococcal sequalae such as rheumatic fever and acute glomerulonephritis have also been described but mainly in developed countries and amongst specific populations. Putative virulence determinants for these organisms include adhesins, toxins, and other factors that are essential for dissemination in human tissues and for interference with the host immune responses. High nucleotide similarities among virulence genes and their association with mobile genetic elements supports the hypothesis of extensive horizontal gene transfer events between the various pyogenic streptococcal species belonging to Lancefield groups A, C and G. A better understanding of the mechanisms of pathogenesis should be apparent by whole-genome sequencing, and this would result in more effective clinical strategies for the pyogenic group in general.
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Affiliation(s)
- Claire E Turner
- Department of Molecular Biology & Biotechnology, The Florey Institute, University of Sheffield, Sheffield, UK
| | - Laura Bubba
- Reference Microbiology Division, National Infection Service, Public Health England, London, United Kingdom
- European Programme for Public Health Microbiology Training (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Androulla Efstratiou
- Reference Microbiology Division, National Infection Service, Public Health England, London, United Kingdom
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Abstract
ABSTRACT
Of the eight phylogenetic groups comprising the genus
Streptococcus
, Lancefield group C and G streptococci (GCS and GGS, resp.) occupy four of them, including the Pyogenic, Anginosus, and Mitis groups, and one Unnamed group so far. These organisms thrive as opportunistic commensals in both humans and animals but may also be associated with clinically serious infections, often resembling those due to their closest genetic relatives, the group A streptoccci (GAS). Advances in molecular genetics, taxonomic approaches and phylogenomic studies have led to the establishment of at least 12 species, several of which being subdivided into subspecies. This review summarizes these advances, citing 264 early and recent references. It focuses on the molecular structure and genetic regulation of clinically important proteins associated with the cell wall, cytoplasmic membrane and extracellular environment. The article also addresses the question of how, based on the current knowledge, basic research and translational medicine might proceed to further advance our understanding of these multifaceted organisms. Particular emphasis in this respect is placed on streptokinase as the protein determining the host specificity of infection and the Rsh-mediated stringent response with its potential for supporting bacterial survival under nutritional stress conditions.
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Solanki V, Tiwari M, Tiwari V. Host-bacteria interaction and adhesin study for development of therapeutics. Int J Biol Macromol 2018; 112:54-64. [PMID: 29414732 DOI: 10.1016/j.ijbiomac.2018.01.151] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/17/2018] [Accepted: 01/21/2018] [Indexed: 12/15/2022]
Abstract
Host-pathogen interaction is one of the most important areas of study to understand the adhesion of the pathogen to the host organisms. To adhere on the host cell surface, bacteria assemble the diverse adhesive structures on its surface, which play a foremost role in targeting to the host cell. We have highlighted different bacterial adhesins which are either protein mediated or glycan mediated. The present article listed examples of different bacterial adhesin proteins involved in the interactions with their host, types and subtypes of the fimbriae and non-fimbriae bacterial adhesins. Different bacterial surface adhesin subunits interact with host via different host surface biomolecules. We have also discussed the interactome of some of the pathogens with their host. Therefore, the present study will help researchers to have a detailed understanding of different interacting bacterial adhesins and henceforth, develop new therapies, adhesin specific antibodies and vaccines, which can effectively control pathogenicity of the pathogens.
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Affiliation(s)
- Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India.
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Abstract
Nosocomial or hospital-acquired infections are associated with prolonged hospitalizations and increased healthcare costs. Infections associated with surgical implants are becoming more difficult and more costly to manage, as they require repeated surgical procedures and a longer period of time to treat patients. Continued advances in the use of medical devices, an increase in the number of immunocompromised patients, and a steady rise in the prevalence of antibiotic-resistant organisms has renewed interest in the development of novel therapies that can be used to prevent and treat nosocomial infections. This review provides an overview of bacterial adhesins and focuses on novel immunological therapies developed to treat staphylococcal infections.
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Affiliation(s)
- J M Patti
- Inhibitex, Inc., Alpharetta, Georgia, USA.
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7
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Stones DH, Al-Saedi F, Vaz D, Perez-Soto N, Krachler AM. Biomimetic Materials to Characterize Bacteria-host Interactions. J Vis Exp 2015. [PMID: 26650964 PMCID: PMC4692734 DOI: 10.3791/53400] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Bacterial attachment to host cells is one of the earliest events during bacterial colonization of host tissues and thus a key step during infection. The biochemical and functional characterization of adhesins mediating these initial bacteria-host interactions is often compromised by the presence of other bacterial factors, such as cell wall components or secreted molecules, which interfere with the analysis. This protocol describes the production and use of biomimetic materials, consisting of pure recombinant adhesins chemically coupled to commercially available, functionalized polystyrene beads, which have been used successfully to dissect the biochemical and functional interactions between individual bacterial adhesins and host cell receptors. Protocols for different coupling chemistries, allowing directional immobilization of recombinant adhesins on polymer scaffolds, and for assessment of the coupling efficiency of the resulting “bacteriomimetic” materials are also discussed. We further describe how these materials can be used as a tool to inhibit pathogen mediated cytotoxicity and discuss scope, limitations and further applications of this approach in studying bacterial - host interactions.
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Affiliation(s)
- Daniel H Stones
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham
| | - Fitua Al-Saedi
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham
| | - Diana Vaz
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham
| | - Nicolas Perez-Soto
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham
| | - Anne M Krachler
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham;
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Hos NJ, Rieg S, Kern WV, Jonas D, Fowler VG, Higgins PG, Seifert H, Kaasch AJ. Amino acid alterations in fibronectin binding protein A (FnBPA) and bacterial genotype are associated with cardiac device related infection in Staphylococcus aureus bacteraemia. J Infect 2014; 70:153-9. [PMID: 25246358 DOI: 10.1016/j.jinf.2014.09.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/26/2014] [Accepted: 09/15/2014] [Indexed: 12/01/2022]
Abstract
OBJECTIVES Staphylococcus aureus initiates cardiac device-related infection (CDI) by binding of fibronectin binding protein A (FnBPA) to the device's surface. In FnBPA, specific "binding enhancing" amino acid alterations are associated with CDI. However, no study has investigated whether these mutations also occur in geographically different regions and whether they arise during infection or are inherent properties of the infecting isolate. METHODS We analysed bacterial isolates from 34 patients with S. aureus bacteraemia and implanted cardiac devices for association with CDI, FnBPA sequence, classification into a clonal complex (CC), and binding to fibronectin (Fn). RESULTS We confirmed that amino acid alterations at positions 652, 782, and 786 in FnBPA were associated with CDI (p = 0.005). Furthermore, CC15 and CC45 isolates were associated with CDI (p = 0.004). All isolates within a CC exhibited a characteristic mutation pattern, with major changes occurring in CC45 including a duplication of D1 and an altered immunogenic epitope in the D3 repeat. Isolates harbouring the "binding enhancing" mutations showed a slightly increased Fn binding capability, whereas Fn binding was decreased in CC45 isolates, according to a microtiter plate assay. CONCLUSIONS FnBPA sequence variations are lineage specific and display inherent properties of the infecting isolate. Sequence analysis of FnBPA, as well as the bacterial genotype, may be used to predict the risk for device-related infection.
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Affiliation(s)
- Nina J Hos
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany
| | - Siegbert Rieg
- Center for Infectious Diseases and Travel Medicine, Department of Medicine, University Hospital of Freiburg, Germany
| | - Winfried V Kern
- Center for Infectious Diseases and Travel Medicine, Department of Medicine, University Hospital of Freiburg, Germany
| | - Daniel Jonas
- Department of Environmental Health Sciences, University Hospital of Freiburg, Germany
| | - Vance G Fowler
- Department of Medicine, Duke University, Durham, NC, USA
| | - Paul G Higgins
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany
| | - Harald Seifert
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany; German Centre for Infection Research (DZIF), Bonn-Cologne, Germany
| | - Achim J Kaasch
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany.
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9
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Kuo CJ, Bell H, Hsieh CL, Ptak CP, Chang YF. Novel mycobacteria antigen 85 complex binding motif on fibronectin. J Biol Chem 2011; 287:1892-902. [PMID: 22128161 DOI: 10.1074/jbc.m111.298687] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The members of the antigen 85 protein family (Ag85), consisting of members Ag85A, Ag85B, and Ag85C, are the predominantly secreted proteins of mycobacteria and possess the ability to specifically interact with fibronectin (Fn). Because Fn-binding proteins are likely to be important virulence factors of Mycobacterium spp., Ag85 may contribute to the adherence, invasion, and dissemination of organisms in host tissue. In this study, we reported the Fn binding affinity of Ag85A, Ag85B, and Ag85C from Mycobacterium avium subsp. paratuberculosis (MAP) (K(D) values were determined from 33.6 to 68.4 nm) and mapped the Ag85-binding motifs of Fn. Fn14, a type III module located on the heparin-binding domain II (Hep-2) of Fn, was discovered to interact with Ag85 from MAP. The peptide inhibition assay subsequently demonstrated that a peptide consisting of residues 17-26 from Fn14 ((17)SLLVSWQPPR(26), termed P17-26) could interfere with Ag85B binding to Fn (73.3% reduction). In addition, single alanine substitutions along the sequence of P17-26 revealed that the key residues involved in Ag85-Fn binding likely contribute through hydrophobic and charge interactions. Moreover, binding of Ag85 on Fn siRNA-transfected Caco2 cells was dramatically reduced (44.6%), implying the physiological significance of the Ag85-Fn interaction between mycobacteria and host cells during infection. Our results indicate that Ag85 binds to Fn at a novel motif and plays a critical role in mycobacteria adherence to host cells by initiating infection. Ag85 might serve as an important colonization factor potentially contributing to mycobacterial virulence.
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Affiliation(s)
- Chih-Jung Kuo
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
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10
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Montanaro L, Speziale P, Campoccia D, Pirini V, Ravaioli S, Cangini I, Visai L, Arciola CR. Polymorphisms of agr locus correspond to distinct genetic patterns of virulence in Staphylococcus aureus clinical isolates from orthopedic implant infections. J Biomed Mater Res A 2010; 94:825-32. [PMID: 20336749 DOI: 10.1002/jbm.a.32764] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Staphylococcus aureus is the leading etiologic agent of orthopedic implant infections. It is endowed with the accessory gene regulator (agr) locus that modulates expression of many virulence genes. Four allelic groups of agr have been recognized within this bacterial species. Here, 200 S. aureus isolates from orthopedic implant infections, typed at the start depending on their agr group, were screened for the presence of adhesin and leukotoxin genes. Interestingly, specific virulence gene patterns emerged in association with agr groups. The most frequently observed agr groups, agr I and agr II, were associated with the presence of sdrE, fib (agr II more than agr I), fnbB (agr I more than agr II), and lukE/lukD (agr II more than agr I). The third more frequent agr group, agr III, differed clearly from agr I and II, exhibiting high prevalence of bbp, generally not harbored by agr I and II, and copresence of bbp with cna, whereas high prevalence of the tandem sdrE/fib marked definitely agr II (91% of agr II isolates), and, though less strictly, agr I, in which prevailed the peculiar fib/fnbB pattern. The only four isolates belonging to agr IV showed full copresence of bbp with fib. Results point out distinct patterns of virulence genes, which underlie distinct evolutive strategies associated to agr groups in S. aureus causing orthopedic implant infections.
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Affiliation(s)
- Lucio Montanaro
- Research Unit on Implant Infections, Rizzoli Orthopaedic Institute, Bologna, Italy
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Lin YP, McDonough SP, Sharma Y, Chang YF. The terminal immunoglobulin-like repeats of LigA and LigB of Leptospira enhance their binding to gelatin binding domain of fibronectin and host cells. PLoS One 2010; 5:e11301. [PMID: 20585579 PMCID: PMC2892007 DOI: 10.1371/journal.pone.0011301] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 05/19/2010] [Indexed: 01/17/2023] Open
Abstract
Leptospira spp. are pathogenic spirochetes that cause the zoonotic disease leptospirosis. Leptospiral immunoglobulin (Ig)-like protein B (LigB) contributes to the binding of Leptospira to extracellular matrix proteins such as fibronectin, fibrinogen, laminin, elastin, tropoelastin and collagen. A high-affinity Fn-binding region of LigB has been localized to LigBCen2, which contains the partial 11th and full 12th Ig-like repeats (LigBCen2R) and 47 amino acids of the non-repeat region (LigBCen2NR) of LigB. In this study, the gelatin binding domain of fibronectin was shown to interact with LigBCen2R (K(D) = 1.91+/-0.40 microM). Not only LigBCen2R but also other Ig-like domains of Lig proteins including LigAVar7'-8, LigAVar10, LigAVar11, LigAVar12, LigAVar13, LigBCen7'-8, and LigBCen9 bind to GBD. Interestingly, a large gain in affinity was achieved through an avidity effect, with the terminal domains, 13th (LigA) or 12th (LigB) Ig-like repeat of Lig protein (LigAVar7'-13 and LigBCen7'-12) enhancing binding affinity approximately 51 and 28 fold, respectively, compared to recombinant proteins without this terminal repeat. In addition, the inhibited effect on MDCKs cells can also be promoted by Lig proteins with terminal domains, but these two domains are not required for gelatin binding domain binding and cell adhesion. Interestingly, Lig proteins with the terminal domains could form compact structures with a round shape mediated by multidomain interaction. This is the first report about the interaction of gelatin binding domain of Fn and Lig proteins and provides an example of Lig-gelatin binding domain binding mediating bacterial-host interaction.
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Affiliation(s)
- Yi-Pin Lin
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Sean P. McDonough
- Department of Biomedical Science, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | | | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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Campylobacter jejuni FlpA binds fibronectin and is required for maximal host cell adherence. J Bacteriol 2010; 192:68-76. [PMID: 19880595 DOI: 10.1128/jb.00969-09] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Campylobacter jejuni is one of the most frequent bacterial causes of food-borne gastrointestinal disease in developed countries. Previous work indicates that the binding of C. jejuni to human intestinal cells is crucial for host colonization and disease. Fibronectin (Fn), a major constituent of the extracellular matrix, is a approximately 250-kDa glycoprotein present at regions of cell-to-cell contact in the intestinal epithelium. Fn is composed of three types of repeating units: type I (approximately 45 amino acids), type II (approximately 60 amino acids), and type III (approximately 90 amino acids). The deduced amino acid sequence of C. jejuni flpA (Cj1279c) contains at least three Fn type III domains. Based on the presence of the Fn type III domains, we hypothesized that FlpA contributes to the binding of C. jejuni to human INT 407 epithelial cells and Fn. We assessed the contribution of FlpA in C. jejuni binding to host cells by in vitro adherence assays with a C. jejuni wild-type strain and a C. jejuni flpA mutant and binding of purified FlpA protein to Fn by enzyme-linked immunosorbent assay (ELISA). Adherence assays revealed the binding of the C. jejuni flpA mutant to INT 407 epithelial cells was significantly reduced compared with that for a wild-type strain. In addition, rabbit polyclonal serum generated against FlpA blocked C. jejuni adherence to INT 407 cells in a concentration-dependent manner. Binding of FlpA to Fn was found to be dose dependent and saturable by ELISA, demonstrating the specificity of the interaction. Based on these data, we conclude that FlpA mediates C. jejuni attachment to host epithelial cells via Fn binding.
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Abstract
Streptococci are clinically important Gram-positive bacteria that are capable to cause a wide variety of diseases in humans and animals. Phylogenetic analyses based on 16S rRNA sequences of the streptococcal species reveal a clustering pattern, reflecting, with a few exceptions, their pathogenic potential and ecological preferences. Microbial adhesion to host tissues is the initial critical event in the pathogenesis of most infections. Streptococci use multiple adhesins to attach to the epithelium, and their expression is regulated in response to environmental and growth conditions. Bacterial adhesins recognize and bind cell surface molecules and extracellular matrix components through specific domains that for certain adhesin families have been well defined and found conserved across the streptococcal species. In this review, we present the different streptococcal adhesin families categorized on the basis of their adhesive properties and structural characteristics, and, when available, we focus the attention on conserved functional domains.
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Affiliation(s)
- Monica Moschioni
- Novartis Vaccines and Diagnostics, Via Fiorentina 1, Siena, Italy
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14
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Liu Y, Strauss J, Camesano TA. Adhesion forces between Staphylococcus epidermidis and surfaces bearing self-assembled monolayers in the presence of model proteins. Biomaterials 2008; 29:4374-82. [PMID: 18760835 DOI: 10.1016/j.biomaterials.2008.07.044] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Accepted: 07/26/2008] [Indexed: 10/21/2022]
Abstract
Self-assembled monolayers (SAMs) are being developed into coatings to reduce microbial biofilm formation on biomaterials. To test anti-adhesion properties, SAMs can be easily constructed on gold, and used to represent a coated biomaterial. However, coatings that prevent bacterial adhesion must also resist protein adsorption. We explored the competitive effects of bacteria and protein for adsorption to SAMs, choosing fetal bovine serum (FBS) to represent protein non-specific binding, and fibronectin (FN) to evaluate ligand/receptor binding. Staphylococcus epidermidis were immobilized on an atomic force microscope (AFM) tip and used as a force probe to detect the interaction forces between bacteria and gold-coated SAMs. The SAMs tested were alkanethiol molecules terminating in isophthalic acid (IPA) or isophthalic acid with silver (IAG). While S. epidermidis showed weak interactions with FBS, the bacteria showed strong adhesion with FN, due to ligand/receptor binding. Bacterial retention and viability experiments were correlated with the force measurements. S. epidermidis interacting with IAG SAMs showed a loss of viability, due to the mobility of silver ions. For most substrata, there was a link between high adhesion forces with bacteria and a high percentage of dead cells being retained on that substratum (even in the absence of a specific biocidal effect, such as silver). This may suggest that high adhesion forces can cause stress to the bacteria which contributed to their death. The relationship between highly adhesive SAMs and bacterial inactivation may be useful in future biomaterial design. When evaluating coatings for biomaterials, it is important to consider the interplay between bacteria, proteins, and the coating material.
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Affiliation(s)
- Yatao Liu
- Department of Chemical Engineering, Life Science and Bioengineering Center at Gateway Park, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
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15
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Meenan NAG, Visai L, Valtulina V, Schwarz-Linek U, Norris NC, Gurusiddappa S, Höök M, Speziale P, Potts JR. The tandem beta-zipper model defines high affinity fibronectin-binding repeats within Staphylococcus aureus FnBPA. J Biol Chem 2007; 282:25893-902. [PMID: 17606607 DOI: 10.1074/jbc.m703063200] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Binding of the fibronectin-binding protein FnBPA from Staphylococcus aureus to the human protein fibronectin has previously been implicated in the development of infective endocarditis, specifically in the processes of platelet activation and invasion of the endothelium. We recently proposed a model for binding of fibronectin to FnBPA in which the bacterial protein contains 11 potential binding sites (FnBPA-1 to FnBPA-11), each composed of motifs that bind to consecutive fibronectin type 1 modules in the N-terminal domain of fibronectin. Here we show that six of the 11 sites bind with dissociation constants in the nanomolar range; other sites bind more weakly. The high affinity binding sites include FnBPA-1, the sequence of which had previously been thought to be encompassed by the fibrinogen-binding A domain of FnBPA. Both the number and sequence conservation of the type-1 module binding motifs appears to be important for high affinity binding. The in vivo relevance of the in vitro binding studies is confirmed by the presence of antibodies in patients with S. aureus infections that specifically recognize complexes of these six high affinity repeats with fibronectin.
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Affiliation(s)
- Nicola A G Meenan
- Department of Biology, University of York, P.O. Box 373, York YO10 5YW, United Kingdom
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16
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Hall AE, Patel PR, Domanski PJ, Prater BD, Gorovits EL, Syribeys PJ, Vernachio JH, Patti JM, Hutchins JT. A panel of monoclonal antibodies recognizing the Staphylococcus epidermidis fibrinogen-binding MSCRAMM SdrG. Hybridoma (Larchmt) 2007; 26:28-34. [PMID: 17316083 DOI: 10.1089/hyb.2006.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Staphylococcus epidermidis is an important opportunistic human pathogen that has recently emerged as a major cause of foreign-body infections. The most important stage contributing to the pathogenesis of this bacteria is the initial adherence to host tissue. SdrG is a cell-wall-anchored fibrinogen-binding adhesin of S. epidermidis that has been shown to be necessary for bacterial binding to fibrinogen-coated foreign bodies, such as catheters. Here we report the generation and characterization of a panel of monoclonal antibodies (MAbs) directed against this S. epidermidis virulence factor. Through the use of multiple in vitro assays, surface plasmon resonance, and flow cytometry, we have characterized a diverse array of MAbs that may prove to be beneficial in studies that address the precise biologic role of SdrG.
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Choy HA, Kelley MM, Chen TL, Møller AK, Matsunaga J, Haake DA. Physiological osmotic induction of Leptospira interrogans adhesion: LigA and LigB bind extracellular matrix proteins and fibrinogen. Infect Immun 2007; 75:2441-50. [PMID: 17296754 PMCID: PMC1865782 DOI: 10.1128/iai.01635-06] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transmission of leptospirosis occurs through contact of mucous membranes and abraded skin with freshwater contaminated by pathogenic Leptospira spp. Exposure to physiological osmolarity induces leptospires to express high levels of the Lig surface proteins containing imperfect immunoglobulin-like repeats that are shared or differ between LigA and LigB. We report that osmotic induction of Lig is accompanied by 1.6- to 2.5-fold increases in leptospiral adhesion to immobilized extracellular matrix and plasma proteins, including collagens I and IV, laminin, and especially fibronectin and fibrinogen. Recombinant LigA-unique and LigB-unique repeat proteins bind to these same host ligands. We found that the avidity of LigB in binding fibronectin is comparable to that of the Staphylococcus aureus FnBPA D repeats. Both LigA- and LigB-unique repeats interact with the amino-terminal fibrin- and gelatin-binding domains of fibronectin, which are also recognized by fibronectin-binding proteins mediating the adhesion of other microbial pathogens. In contrast, repeats common to both LigA and LigB do not bind these host proteins, and nonrepeat sequences in the carboxy-terminal domain of LigB show only weak interaction with fibronectin and fibrinogen. A functional role for the binding activity of LigA and LigB is suggested by the ability of the recombinants to inhibit leptospiral adhesion to fibronectin by 28% and 21%, respectively. The binding of LigA and LigB to multiple ligands present in different tissues suggests that these adhesins may be involved in the initial colonization and dissemination stages of leptospirosis. The characterization of the Lig adhesin function should aid the design of Lig-based vaccines and serodiagnostic tests.
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Affiliation(s)
- Henry A Choy
- Division of Infectious Diseases, 111F, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073, USA.
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18
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Rafii MS, Hagiwara H, Mercado ML, Seo NS, Xu T, Dugan T, Owens RT, Hook M, McQuillan DJ, Young MF, Fallon JR. Biglycan binds to alpha- and gamma-sarcoglycan and regulates their expression during development. J Cell Physiol 2006; 209:439-47. [PMID: 16883602 PMCID: PMC2929672 DOI: 10.1002/jcp.20740] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The dystrophin-associated protein complex (DAPC), which links the cytoskeleton to the extracellular matrix, is essential for muscle cell survival, and is defective in a wide range of muscular dystrophies. The DAPC contains two transmembrane subcomplexes-the dystroglycans and the sarcoglycans. Although several extracellular binding partners have been identified for the dystroglycans, none have been described for the sarcoglycan subcomplex. Here we show that the small leucine-rich repeat (LRR) proteoglycan biglycan binds to alpha- and gamma-sarcoglycan as judged by ligand blot overlay and co-immunoprecipitation assays. Our studies with biglycan-decorin chimeras show that alpha- and gamma-sarcoglycan bind to distinct sites on the polypeptide core of biglycan. Both biglycan proteoglycan as well as biglycan polypeptide lacking glycosaminoglycan (GAG) side chains are components of the dystrophin glycoprotein complex isolated from adult skeletal muscle membranes. Finally, our immunohistochemical and biochemical studies with biglycan null mice show that the expression of alpha- and gamma-sarcoglycan is selectively reduced in muscle from young (P14-P21) animals, while levels in adult muscle (> or = P35) are unchanged. We conclude that biglycan is a ligand for two members of the sarcoglycan complex and regulates their expression at discrete developmental ages.
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Affiliation(s)
- Michael S. Rafii
- Department of Neuroscience, Brown University, Providence RI, 02912
| | - Hiroki Hagiwara
- Department of Neuroscience, Brown University, Providence RI, 02912
| | | | | | - Tianshun Xu
- Craniofacial and Skeletal Diseases Branch, National Institutes of Dental Research, National Institutes of Health, Bethesda MD, 20892
| | - Tracey Dugan
- Texas A&M University System Health Science Center Institute of Biosciences and Technology
| | | | - Magnus Hook
- Texas A&M University System Health Science Center Institute of Biosciences and Technology
| | | | - Marian F. Young
- Craniofacial and Skeletal Diseases Branch, National Institutes of Dental Research, National Institutes of Health, Bethesda MD, 20892
| | - Justin R. Fallon
- Department of Neuroscience, Brown University, Providence RI, 02912
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19
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Schwarz-Linek U, Höök M, Potts JR. Fibronectin-binding proteins of Gram-positive cocci. Microbes Infect 2006; 8:2291-8. [PMID: 16782385 DOI: 10.1016/j.micinf.2006.03.011] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Accepted: 03/06/2006] [Indexed: 11/30/2022]
Abstract
Cell wall-attached fibronectin-binding proteins are important multifunctional virulence factors of Staphylococcus aureus and Streptococcus pyogenes. This review describes recent advances in the understanding of the function of these proteins on a molecular level and of their role in infections.
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Affiliation(s)
- Ulrich Schwarz-Linek
- Centre for Biomolecular Sciences, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK.
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20
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Dabo SM, Confer AW, Anderson BE, Gupta S. Bartonella henselae Pap31, an extracellular matrix adhesin, binds the fibronectin repeat III13 module. Infect Immun 2006; 74:2513-21. [PMID: 16622186 PMCID: PMC1459717 DOI: 10.1128/iai.74.5.2513-2521.2006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Bartonella henselae wound-associated infections suggest involvement of extracellular matrix molecules in adhesion and invasion. Pap31 was previously identified as a hemin-binding protein. Our recent studies suggest the protein is an adhesin that is recognized by the host's immune systems. In this study we examined the interactions of B. henselae Pap31 with fibronectin (Fn), heparin (Hep), and human umbilical vein endothelial cells (HUVECs). The cloned gene was expressed in Escherichia coli, and the purified Pap31 protein elicited strong antibody responses in mice and was reactive with rabbit anti-live B. henselae and mouse anti-Pap31 antibodies by Western blotting. Pap31 bound to immobilized Fn and to HUVECs in a dose-dependent manner and to Hep. Fn fragment-binding assays identified the Hep-1 and Hep-2 binding domains of human Fn and in particular the (12-13)FnIII repeat module as primary binding sites for this adhesin. Furthermore, Pap31 binding to the above Fn fragments could be inhibited by Hep, suggesting a common binding site involving the 13FnIII repeat module on the Hep-2 domain of Fn. Adherence of intact B. henselae to HUVECs was inhibited by increasing concentrations of anti-Pap31 antibodies. In addition, purified Pap31 coprecipitated effectively with Fn and anti-Fn antibodies. Taken together, these data suggest that Pap31 is an Fn-binding protein mediating the B. henselae-host interaction(s), and they implicate the 13FnIII repeat module as an important binding site for this adhesin on the Fn molecule. These interactions may be important initial steps leading to bacterial attachment and colonization that promote the establishment of B. henselae infections in vivo.
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Affiliation(s)
- S M Dabo
- Department of Veterinary Pathobiology, Room 250 McElroy Hall, Oklahoma State University, Stillwater, OK 74078-2007, USA.
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21
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Kreikemeyer B, Nakata M, Oehmcke S, Gschwendtner C, Normann J, Podbielski A. Streptococcus pyogenes collagen type I-binding Cpa surface protein. Expression profile, binding characteristics, biological functions, and potential clinical impact. J Biol Chem 2005; 280:33228-39. [PMID: 16040603 DOI: 10.1074/jbc.m502896200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Streptococcus pyogenes collagen type I-binding protein Cpa (collagen-binding protein of group A streptococci) expressed by 28 serotypes of group A streptococci has been extensively characterized at the gene and protein levels. Evidence for three distinct families of cpa genes was found, all of which shared a common sequence encoding a 60-amino acid domain that accounted for selective binding to type I collagen. Surface plasmon resonance-based affinity measurements and functional studies indicated that the expression of Cpa was consistent with an attachment role for bacteria to tissue containing collagen type I. A cpa mutant displayed a significantly decreased internalization rate when incubated with HEp-2 cells but had no effect on the host cell viability. By utilizing serum from patients with a positive titer for streptolysin/DNase antibody, an increased anti-Cpa antibody titer was noted for patients with a clinical history of arthritis or osteomyelitis. Taken together, these results suggest Cpa may be a relevant matrix adhesin contributing to the pathogenesis of S. pyogenes infection of bones and joints.
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Affiliation(s)
- Bernd Kreikemeyer
- Department of Medical Microbiology and Hospital Hygiene, Hospital of Rostock University, Schillingallee 70, D-18057 Rostock, Germany
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22
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Que YA, Haefliger JA, Piroth L, François P, Widmer E, Entenza JM, Sinha B, Herrmann M, Francioli P, Vaudaux P, Moreillon P. Fibrinogen and fibronectin binding cooperate for valve infection and invasion in Staphylococcus aureus experimental endocarditis. ACTA ACUST UNITED AC 2005; 201:1627-35. [PMID: 15897276 PMCID: PMC2212930 DOI: 10.1084/jem.20050125] [Citation(s) in RCA: 218] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The expression of Staphylococcus aureus adhesins in Lactococcus lactis identified clumping factor A (ClfA) and fibronectin-binding protein A (FnBPA) as critical for valve colonization in rats with experimental endocarditis. This study further analyzed their role in disease evolution. Infected animals were followed for 3 d. ClfA-positive lactococci successfully colonized damaged valves, but were spontaneously eradicated over 48 h. In contrast, FnBPA-positive lactococci progressively increased bacterial titers in vegetations and spleens. At imaging, ClfA-positive lactococci were restricted to the vegetations, whereas FnBPA-positive lactococci also invaded the adjacent endothelium. This reflected the capacity of FnBPA to trigger cell internalization in vitro. Because FnBPA carries both fibrinogen- and fibronectin-binding domains, we tested the role of these functionalities by deleting the fibrinogen-binding domain of FnBPA and supplementing it with the fibrinogen-binding domain of ClfA in cis or in trans. Deletion of the fibrinogen-binding domain of FnBPA did not alter fibronectin binding and cell internalization in vitro. However, it totally abrogated valve infectivity in vivo. This ability was restored in cis by inserting the fibrinogen-binding domain of ClfA into truncated FnBPA, and in trans by coexpressing full-length ClfA and truncated FnBPA on two separate plasmids. Thus, fibrinogen and fibronectin binding could cooperate for S. aureus valve colonization and endothelial invasion in vivo.
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MESH Headings
- Adhesins, Bacterial/genetics
- Adhesins, Bacterial/metabolism
- Animals
- Bacterial Adhesion/genetics
- Coagulase/genetics
- Coagulase/metabolism
- Endocarditis, Bacterial/metabolism
- Endocarditis, Bacterial/microbiology
- Endocarditis, Bacterial/pathology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/microbiology
- Endothelium, Vascular/pathology
- Female
- Fibrinogen/metabolism
- Fibronectins/metabolism
- Heart Valves/metabolism
- Heart Valves/microbiology
- Heart Valves/pathology
- Lactococcus lactis/genetics
- Lactococcus lactis/pathogenicity
- Protein Binding
- Protein Structure, Tertiary/genetics
- Rats
- Rats, Wistar
- Sequence Deletion
- Spleen/metabolism
- Spleen/microbiology
- Spleen/pathology
- Staphylococcal Infections/metabolism
- Staphylococcal Infections/microbiology
- Staphylococcal Infections/pathology
- Staphylococcus aureus/genetics
- Staphylococcus aureus/pathogenicity
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Affiliation(s)
- Yok-Ai Que
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
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23
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Kintarak S, Nair SP, Speight PM, Whawell SA. A recombinant fragment of the fibronectin-binding protein of Staphylococcus aureus inhibits keratinocyte migration. Arch Dermatol Res 2005; 296:250-7. [PMID: 15503090 DOI: 10.1007/s00403-004-0515-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Staphylococcus aureus is a common wound-infecting organism which can interact with cells via the extracellular matrix protein fibronectin (FN). The aim of this study was to determine the effect of the FN-binding protein (FnBP) of S. aureus on the behaviour of a human skin keratinocytes cell line (UP). FN-coated plates and Transwell membranes were exposed to a recombinant protein encompassing the D1-D4 repeat region of S. aureus FnBPB (rFnBPBD1-D4) before cell adhesion and migration assays. The influence of this protein on migration into a wounded area, cell cycle progression and endogenous cellular FN assembly was also assessed. The rFnBPBD1-D4 protein potently inhibited S. aureus entry into UP keratinocytes but had no effect on cell adhesion to FN substrate. It inhibited UP keratinocyte Transwell migration by 17% (P= 0.04) and 31% (P=0.02) at 10 and 100 microg/ml, respectively. In the wound assay, 100 microg/ml of rFnBPBD1-D4 protein reduced the migration area by approximately 30%. No differences in cell cycle progression were observed. In the presence of rFnBPBD1-D4, most of the cellular FN matrix on the cell surface and along the cell filopodia seen in untreated cells was absent. Interaction of S. aureus FnBPs with FN may influence cell behaviour and thus play a role in delayed epithelial closure in infected healing wounds.
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Affiliation(s)
- Sompid Kintarak
- Department of Stomatology, Faculty of Dentistry, Prince of Songkla University, Hatyai, 90112 Songkhla, Thailand
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24
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Gomes AR, Vinga S, Zavolan M, de Lencastre H. Analysis of the genetic variability of virulence-related loci in epidemic clones of methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 2005; 49:366-79. [PMID: 15616317 PMCID: PMC538922 DOI: 10.1128/aac.49.1.366-379.2005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) isolates have previously been classified into major epidemic clonal types by pulsed-field gel electrophoresis in combination with multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec typing. We aimed to investigate whether genetic variability in potentially polymorphic domains of virulence-related factors could provide another level of differentiation in a diverse collection of epidemic MRSA clones. The target regions of strains representative of epidemic clones and genetically related methicillin-susceptible S. aureus isolates from the 1960s that were sequenced included the R domains of clfA and clfB; the D, W, and M regions of fnbA and fnbB; and three regions in the agr operon. Sequence variation ranged from very conserved regions, such as those for RNAIII and the agr interpromoter region, to the highly polymorphic R regions of the clf genes. The sequences of the clf R domains could be grouped into six major sequence types on the basis of the sequences in their 3' regions. Six sequence types were also observed for the fnb sequences at the amino acid level. From an evolutionary point of view, it was interesting that a small DNA stretch at the 3' clf R-domain sequence and the fnb sequences agreed with the results of MLST for this set of strains. In particular, clfB R-domain sequences, which had a high discriminatory capacity and with which the types distinguished were congruent with those obtained by other molecular typing methods, have potential for use for the typing of S. aureus. Clone- and strain-specific sequence motifs in the clf and fnb genes may represent useful additions to a typing methodology with a DNA array.
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Affiliation(s)
- A R Gomes
- Laboratory of Molecular Genetics, Universidade Nova de Lisboa, Oeiras, Portugal
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25
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Schwarz-Linek U, Pilka ES, Pickford AR, Kim JH, Höök M, Campbell ID, Potts JR. High Affinity Streptococcal Binding to Human Fibronectin Requires Specific Recognition of Sequential F1 Modules. J Biol Chem 2004; 279:39017-25. [PMID: 15247227 DOI: 10.1074/jbc.m405083200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fibronectin (Fn) binding by the Streptococcus pyogenes protein SfbI has been shown to trigger integrin-dependent internalization of this pathogen by human epithelial and endothelial cells. Here, using nuclear magnetic resonance spectroscopy and isothermal titration calorimetry in a dissection approach, the basis for the specificity and high affinity of the interaction between the N-terminal domain of Fn and SfbI is revealed. Each of the five Fn type 1 modules is directly involved in the interaction and is recognized by short consecutive motifs within the repeat region of SfbI. Crucially, these motifs must be combined in the correct order to form a high affinity ligand for the N-terminal domain of Fn.
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Affiliation(s)
- Ulrich Schwarz-Linek
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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26
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Ingham KC, Brew S, Vaz D, Sauder DN, McGavin MJ. Interaction of Staphylococcus aureus fibronectin-binding protein with fibronectin: affinity, stoichiometry, and modular requirements. J Biol Chem 2004; 279:42945-53. [PMID: 15294899 DOI: 10.1074/jbc.m406984200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The repetitive D1, D2, and D3 elements of Staphylococcus aureus fibronectin-binding protein FnBPA each bind the N-terminal 29-kDa fragment (N29) of fibronectin with low micromolar dissociation constants (Kd), but in tandem they compose a high affinity domain, D1-3. An additional seven Fn-binding segments have been predicted in FnBPA in a region N-terminal of the D-repeats (Schwarz-Linek, U., Werner, J. M., Pickford, A. R., Gurusiddappa, S., Kim, J. H., Pilka, E. S., Briggs, J. A., Gough, T. S., Hook, M., Campbell, I. D., and Potts, J. R. (2003) Nature 423, 177-181). We have evaluated the requirements for high affinity binding of N29 to the D-repeat domain and determined the affinity and stoichiometry of N29 binding to segments that are N-terminal of the D-repeats in the related FnBPB adhesin. We confirmed that D1-3 has two equivalent high affinity sites (Kd, approximately 1 nm) and provided evidence for one or more lower affinity sites (Kd, approximately 0.5 microm). Bimodular D1-2 and D2-3 exhibit intermediate affinity sites with respective Kd values of 0.25 and 0.044 microm, as well as a low affinity site with a Kd value of 2.2-2.5 microm. We also identified two binding domains that are N-terminal of the D-repeats, designated DuB and DuA. Segments internal to these domains individually bound N29 with similar Kd values of approximately 2 microm, whereas the DuBA polypeptide possessing both segments and other intervening sites bound four molecules of N29 with much higher affinity (Kd, approximately 10 nm). DuBAD, a larger polypeptide harboring all of the known or predicted binding motifs in FnBPB, bound seven to eight molecules of N29, with a Kd of approximately 7 nm. Because most of the isolated binding segments display low affinity for N29 and lack motifs for binding of one or both of the 1F1 and 5F1 modules in the N-terminal domain of Fn, we propose that high affinity is achieved in part as a consequence of self-interaction between bound molecules of N29.
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Affiliation(s)
- Kenneth C Ingham
- Department of Biochemistry, American Red Cross Holland Laboratory, Rockville, Maryland 20855, USA
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27
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Kim JH, Singvall J, Schwarz-Linek U, Johnson BJB, Potts JR, Höök M. BBK32, a fibronectin binding MSCRAMM from Borrelia burgdorferi, contains a disordered region that undergoes a conformational change on ligand binding. J Biol Chem 2004; 279:41706-14. [PMID: 15292204 DOI: 10.1074/jbc.m401691200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BBK32 is a fibronectin-binding lipoprotein on Borrelia burgdorferi, the causative agent of Lyme disease. Analysis using secondary structure prediction programs suggested that BBK32 is composed of two domains, an N-terminal segment lacking well defined secondary structure and a C-terminal segment composed largely of alpha-helices. Analysis of purified recombinant forms of the two domains by circular dichroism spectroscopy, gel permeation chromatography, and intrinsic viscosity determination were consistent with an N-terminal-extended, unstructured segment and a C-terminal globular domain in BBK32. Solid phase binding experiments suggest that the unstructured N-terminal domain binds fibronectin. Analysis of changes in circular dichroism spectra of the N-terminal segment of BBK32 upon binding of the N-terminal domain of fibronectin revealed an increase in beta-sheet content in the complex. Hence, BBK32, which belongs to a different family of proteins and shows no overall sequence similarity with the fibronectin binding MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) of Gram-positive bacteria, binds fibronectin by a mechanism that is reminiscent of the "tandem beta-zipper" previously demonstrated for the fibronectin binding of streptococcal adhesins.
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Affiliation(s)
- Jung Hwa Kim
- Center for Extracellular Matrix Biology, Albert B. Alkek Institute of Biosciences and Technology, Texas A and M University System Health Science Center, Houston, Texas 77030, USA
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28
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Roche FM, Downer R, Keane F, Speziale P, Park PW, Foster TJ. The N-terminal A domain of fibronectin-binding proteins A and B promotes adhesion of Staphylococcus aureus to elastin. J Biol Chem 2004; 279:38433-40. [PMID: 15234962 DOI: 10.1074/jbc.m402122200] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ability of Staphylococcus aureus to adhere to components of the extracellular matrix is an important mechanism for colonization of host tissues during infection. We have previously shown that S. aureus binds elastin, a major component of the extracellular matrix. The integral membrane protein, elastin-binding protein (EbpS), binds soluble elastin peptides and tropoelastin via its surface-exposed N-terminal domain. In this study, we demonstrate that some strains of S. aureus adhere strongly to immobilized human elastin and that this interaction is independent of EbpS but instead is mediated by the fibronectin-binding proteins, FnBPA and FnBPB. Our results show that EbpS mutant cells adhere to elastin-coated plates, whereas the cells negative for FnBPA and FnBPB do not adhere to the plates. Furthermore, only wild-type cells from the exponential phase of growth adhered when FnBPs were expressed maximally. We show that adherence to elastin promoted by FnBPA was not affected by soluble fibronectin, suggesting that the elastin binding domain is distinct from the fibronectin binding regions. Recombinant FnBPA(37-544) (rFnBPA(37-544)) protein corresponding to the A region of FnBPA and anti-FnBPA(37-544) antibodies inhibited FnBPA-mediated bacterial adherence to immobilized elastin. Finally, recombinant A domain proteins, rFnBPA(37-544) and rFnBPB(37-540), bound immobilized elastin dose-dependently and saturably. This interaction was inhibited by soluble elastin peptides, suggesting a specific receptor-ligand interaction.
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Affiliation(s)
- Fiona M Roche
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland
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29
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Ito HO, Soutome S, Nokihara K, Inoue M. Identification and characterization of bacterial-binding property in the type III repeat domain of fibronectin. Biochem Biophys Res Commun 2004; 320:347-53. [PMID: 15219833 DOI: 10.1016/j.bbrc.2004.05.170] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2004] [Indexed: 11/17/2022]
Abstract
To characterize fibronectin binding with Granulicatella adiacens, a causative agent of infective endocarditis, monoclonal antibodies were generated against human fibronectin and selected for their capacity to inhibit the fibronectin binding of the organism. Thermolysin and lysyl-endopeptidase digests of fibronectin were characterized by Western blot. The epitope of inhibitory monoclonal antibody was found in the central portion of fibronectin known as the cell-binding domain, and not in the N-terminal portion known to be the binding region of most microbial species, e.g., Staphylococcus aureus and Streptococcus pyogenes. While these two species could bind to both the N-terminal and central portion, Escherichia coli and G. adiacens bind only to the latter. Excess amounts of free fibronectin in the solution inhibited the bacterial adherence to the N-terminal fibronectin fragment, but not to the central region, thereby suggesting the central region plays a significant role for in vivo bacterial colonization in the presence of high concentrations of soluble fibronectin.
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Affiliation(s)
- Hiro-O Ito
- Department of Preventive Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan.
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30
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Schwarz-Linek U, Höök M, Potts JR. The molecular basis of fibronectin-mediated bacterial adherence to host cells. Mol Microbiol 2004; 52:631-41. [PMID: 15101971 DOI: 10.1111/j.1365-2958.2004.04027.x] [Citation(s) in RCA: 205] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many pathogenic Gram-positive bacteria produce cell wall-anchored proteins that bind to components of the extracellular matrix (ECM) of the host. These bacterial MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) are thought to play a critical role in infection. One group of MSCRAMMs, produced by staphylococci and streptococci, targets fibronectin (Fn, a glycoprotein found in the ECM and body fluids of vertebrates) using repeats in the C-terminal region of the bacterial protein. These bacterial Fn-binding proteins (FnBPs) mediate adhesion to host tissue and bacterial uptake into non-phagocytic host cells. Recent studies on interactions between the host and bacterial proteins at the residue-specific level and on the mechanism of host cell invasion are providing a much clearer picture of these processes.
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Affiliation(s)
- Ulrich Schwarz-Linek
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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Schwarz-Linek U, Werner JM, Pickford AR, Gurusiddappa S, Kim JH, Pilka ES, Briggs JAG, Gough TS, Höök M, Campbell ID, Potts JR. Pathogenic bacteria attach to human fibronectin through a tandem beta-zipper. Nature 2003; 423:177-81. [PMID: 12736686 DOI: 10.1038/nature01589] [Citation(s) in RCA: 280] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2002] [Accepted: 03/21/2003] [Indexed: 11/09/2022]
Abstract
Staphylococcus aureus and Streptococcus pyogenes, two important human pathogens, target host fibronectin (Fn) in their adhesion to and invasion of host cells. Fibronectin-binding proteins (FnBPs), anchored in the bacterial cell wall, have multiple Fn-binding repeats in an unfolded region of the protein. The bacterium-binding site in the amino-terminal domain (1-5F1) of Fn contains five sequential Fn type 1 (F1) modules. Here we show the structure of a streptococcal (S. dysgalactiae) FnBP peptide (B3) in complex with the module pair 1F12F1. This identifies 1F1- and 2F1-binding motifs in B3 that form additional antiparallel beta-strands on sequential F1 modules-the first example of a tandem beta-zipper. Sequence analyses of larger regions of FnBPs from S. pyogenes and S. aureus reveal a repeating pattern of F1-binding motifs that match the pattern of F1 modules in 1-5F1 of Fn. In the process of Fn-mediated invasion of host cells, therefore, the bacterial proteins seem to exploit the modular structure of Fn by forming extended tandem beta-zippers. This work is a vital step forward in explaining the full mechanism of the integrin-dependent FnBP-mediated invasion of host cells.
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Affiliation(s)
- Ulrich Schwarz-Linek
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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Elgalai I, Foster HA. Comparison of adhesion of wound isolates of Staphylococcus aureus to immobilized proteins. J Appl Microbiol 2003; 94:413-20. [PMID: 12588550 DOI: 10.1046/j.1365-2672.2003.01858.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To determine the ability of 149 clinical isolates of Staphylococcus aureus from burns, other wounds and environmental isolates to adhere to immobilized proteins. METHODS AND RESULTS The ability to bind to immobilized fibrinogen, fibronectin, laminin, collagen, IgG and lysozyme was studied using a microtitre plate assay. The strains were very diverse. Binding to fibrinogen was most frequent, followed by fibronectin, collagen and laminin. Binding to IgG and lysozyme was weak and few strains showed strong binding. Numerical analysis showed that 65% of the strains infecting burns had similar properties and bound to fibrinogen, fibronectin, collagen and IgG. The strains infecting other wounds had more variable characteristics. CONCLUSIONS The ability to adhere to proteins is important in wound infection, but clinical isolates were diverse in their ability to bind to the proteins tested. Burn wounds were more likely to be infected with strains showing multiple binding characteristics. SIGNIFICANCE AND IMPACT OF THE STUDY The study confirms the importance of adhesins in clinical infection.
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Affiliation(s)
- I Elgalai
- Biosciences Research Institute, School of Environment and Life Sciences, University of Salford, Salford, Lancs, UK
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33
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Visai L, De Rossi E, Valtulina V, Casolini F, Rindi S, Guglierame P, Pietrocola G, Bellotti V, Riccardi G, Speziale P. Identification and characterization of a new ligand-binding site in FnbB, a fibronectin-binding adhesin from Streptococcus dysgalactiae. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1646:173-83. [PMID: 12637025 DOI: 10.1016/s1570-9639(03)00020-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Streptococcus dysgalactiae S2, a bovine mastitis isolate, expresses the fibronectin (Fn)-binding adhesin FnbB. Here, we describe a new fibronectin-binding domain called UFnBD, located 100 amino acid N-terminal to the primary repetitive Fn-binding domain (FnBRD-B) of FnbB. UFnBD interacted with N-terminal region of Fn (N29) and this binding was mostly mediated by type I module pair 2-3 of N29 fragment, whereas FnBRD-B mainly bound to type I module pair 4-5. Furthermore, UFnBD inhibited adherence of S. dysgalactiae to Fn but at lower level as compared to FnBRD-B. UFnBD exclusively shared antigenic properties with the Fn-binding unit Du of FnbpA from Staphylococcus aureus but not with ligand-binding domains or motifs of other adhesins, while Fn-induced determinants of FnBRD-B and other adhesins appeared to be conformationally related. Consistent with this, a monoclonal antibody 7E11 generated from a mouse immunized with FnbB, and that recognized UFnBD did not cross-react with FnBRD-B. The epitope for 7E11 was mapped to 40 amino acid long segment within UFnBD and interaction between the antibody and the epitope was specifically induced by Fn or N29. A similar antibody epitope was observed in Streptococcus pyogenes strains suggesting the presence of an adhesin bearing epitope related to FnbB.
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Affiliation(s)
- Livia Visai
- Department of Biochemistry, University of Pavia, Italy
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34
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Shinji H, Seki K, Tajima A, Uchida A, Masuda S. Fibronectin bound to the surface of Staphylococcus aureus induces association of very late antigen 5 and intracellular signaling factors with macrophage cytoskeleton. Infect Immun 2003; 71:140-6. [PMID: 12496159 PMCID: PMC143151 DOI: 10.1128/iai.71.1.140-146.2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus Cowan I and a clinically isolated coagulase-negative Staphylococcus strain, S. saprophyticus 10312, were found to have two fibronectin binding proteins, FnBPA and FnBPB. While both staphylococci bound to serum fibronectin to a similar extent, fibronectin binding significantly increased the phagocytic activity of macrophages against S. aureus (by ca. 150%) but not against S. saprophyticus. This enhancing effect of fibronectin was inhibited by an RGD sequence-containing peptide and also by anti-very late antigen 5 antibody. This suggests that the effect is mediated by very late antigen 5 expressed on macrophages. In macrophages ingesting fibronectin-bound Cowan I, alpha(5) and beta(1) chains were associated with the cytoskeleton. Cytosolic signaling factors such as paxillin, c-Src, and c-Csk were also associated with the cytoskeleton. On the contrary, beta(3) integrin transiently disappeared from the cytoskeleton when macrophages ingested the fibronectin-treated S. aureus Cowan I. Furthermore, the Src kinase family tyrosine kinase Lyn dissociated from the cytoskeleton. These cellular components did not respond in a fibronectin-dependent manner when macrophages phagocytosed S. saprophyticus. This means that only fibronectin-treated S. aureus Cowan I induces the accumulation of very late antigen 5, which in turn induces the association of paxillin and tyrosine kinases. It is thought that the phagocytic activity of macrophages against fibronectin-treated S. aureus was increased by signaling via the activation of very late antigen 5.
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Affiliation(s)
- Hitomi Shinji
- Department of Microbiology II, Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan.
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35
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Williams RJ, Henderson B, Sharp LJ, Nair SP. Identification of a fibronectin-binding protein from Staphylococcus epidermidis. Infect Immun 2002; 70:6805-10. [PMID: 12438356 PMCID: PMC133053 DOI: 10.1128/iai.70.12.6805-6810.2002] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus epidermidis has been reported to bind to a number of host cell extracellular matrix proteins, including fibronectin. Here we report the identification of a fibronectin-binding protein from S. epidermidis. A phage display library of S. epidermidis genomic DNA was constructed and panned against immobilized fibronectin. A number of phagemid clones containing overlapping inserts were identified, and one of these clones, pSE109FN, contained a 1.4-kb insert. Phage pSE109FN was found to bind to fibronectin but not to collagen, fibrinogen, laminin, or vitronectin. However, pSE109FN also bound to heparin, hyaluronate, and plasminogen, although to a lesser extent than it bound to fibronectin. Analysis of The Institute for Genomic Research S. epidermidis genome sequence database revealed a 1.85-kb region within a putative 30.5-kb open reading frame, to which the overlapping DNA inserts contained within the fibronectin-binding phagemids mapped. We have designated the gene encoding the fibronectin-binding domain embp. A recombinant protein, Embp32, which encompassed the fibronectin-binding domain of Embp, blocked the binding of S. epidermidis, but not the binding of Staphylococcus aureus, to fibronectin. In contrast, a recombinant protein, FnBPB[D1-D4], spanning the fibronectin-binding domain of the S. aureus fibronectin-binding protein FnBPB, blocked binding of S. aureus to fibronectin but had a negligible effect on the binding of S. epidermidis.
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Affiliation(s)
- Rachel J Williams
- Cellular Microbiology Research Group, Eastman Dental Institute for Oral Health Care Sciences, University College London, United Kingdom
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36
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Terao Y, Kawabata S, Kunitomo E, Nakagawa I, Hamada S. Novel laminin-binding protein of Streptococcus pyogenes, Lbp, is involved in adhesion to epithelial cells. Infect Immun 2002; 70:993-7. [PMID: 11796638 PMCID: PMC127702 DOI: 10.1128/iai.70.2.993-997.2002] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The lbp gene, which encodes a laminin-binding protein (Lbp) of Streptococcus pyogenes, was found in all S. pyogenes M types. An Lbp-deficient mutant showed a significantly lower efficiency of adhesion to HEp-2 cells than did the wild-type strain. These results indicate that Lbp is one of the important S. pyogenes adhesins.
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Affiliation(s)
- Yutaka Terao
- Department of Oral Microbiology, Osaka University Faculty of Dentistry, Suita-Osaka 565-0871, Japan
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37
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Massey RC, Kantzanou MN, Fowler T, Day NP, Schofield K, Wann ER, Berendt AR, Höök M, Peacock SJ. Fibronectin-binding protein A of Staphylococcus aureus has multiple, substituting, binding regions that mediate adherence to fibronectin and invasion of endothelial cells. Cell Microbiol 2001; 3:839-51. [PMID: 11736995 DOI: 10.1046/j.1462-5822.2001.00157.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Invasive Staphylococcus aureus infection frequently involves bacterial seeding from the bloodstream to other body tissues, a process necessarily involving interactions between circulating bacteria and vascular endothelial cells. Staphylococcus aureus fibronectin-binding protein is central to the invasion of endothelium, fibronectin forming a bridge between bacterial fibronectin-binding proteins and host cell receptors. To dissect further the mechanisms of invasion of endothelial cells by S. aureus, a series of truncated FnBPA proteins that lacked one or more of the A, B, C or D regions were expressed on the surface of S. aureus and tested in fibronectin adhesion, endothelial cell adhesion and invasion assays. We found that this protein has multiple, substituting, fibronectin-binding regions, each capable of conferring both adherence to fibronectin and endothelial cells, and endothelial cell invasion. By expressing S. aureus FnBPA on the surface of the non-invasive Gram-positive organism Lactococcus lactis, we have found that no other bacterial factor is required for invasion. Furthermore, we have demonstrated that, as with other cell types, invasion of endothelial cells is mediated by integrin alpha5beta1. These findings may be of relevance to the development of preventive measures against systemic infection, and bacterial spread in the bacteraemic patient.
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Affiliation(s)
- R C Massey
- Nuffield Department of Clinical Laboratory Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
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38
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Terao Y, Kawabata S, Kunitomo E, Murakami J, Nakagawa I, Hamada S. Fba, a novel fibronectin-binding protein from Streptococcus pyogenes, promotes bacterial entry into epithelial cells, and the fba gene is positively transcribed under the Mga regulator. Mol Microbiol 2001; 42:75-86. [PMID: 11679068 DOI: 10.1046/j.1365-2958.2001.02579.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In infection by Streptococcus pyogenes, fibronectin (Fn)-binding proteins play important roles as adhesins and invasins. Here, we present a novel Fn-binding protein of S. pyogenes that exhibits a low similarity to other Fn-binding proteins reported. After searching the Oklahoma Streptococcal Genome Sequencing Database for open reading frames (ORFs) with an LPXTG motif, nine ORFs were found among those recognized as putative surface proteins, and one of them was designated as Fba. The fba gene was found in M types 1, 2, 4, 22, 28 and 49 of S. pyogenes, but not in other serotypes or groups of streptococci. Fba, a 37.8 kDa protein, possesses three or four proline-rich repeat domains and exhibits a high homology to FnBPA, the Fn-binding protein of Staphylococcus aureus. Recombinant Fba exhibited a strong binding ability to Fn. In addition, Fba-deficient mutants showed diminished invasive capabilities to HEp-2 cells and low mortality in mice following skin infection. The fba gene was located downstream of the mga regulon and analysis using an mga-inactivated mutant revealed that it was transcribed under the control of the Mga regulator. These results indicate that Fba is a novel protein and one of the important virulence factors of S. pyogenes.
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Affiliation(s)
- Y Terao
- Department of Oral Microbiology, Osaka University Faculty of Dentistry, Suita-Osaka 565-0871, Japan
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39
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Cho SH, Strickland I, Boguniewicz M, Leung DY. Fibronectin and fibrinogen contribute to the enhanced binding of Staphylococcus aureus to atopic skin. J Allergy Clin Immunol 2001; 108:269-74. [PMID: 11496245 DOI: 10.1067/mai.2001.117455] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Staphylococcus aureus colonizes the skin lesions of more than 90% of patients with atopic dermatitis (AD). The mechanism for increased S aureus colonization in AD is unknown. However, the initial event in colonization requires adherence of S aureus to the skin. OBJECTIVE The purpose of this study was to examine the roles of various bacterial adhesins on S aureus binding to AD skin. METHODS In an attempt to delineate the mechanism behind this adherence process, an in vitro bacterial binding assay was developed to quantitate the adherence of various S aureus strains to AD, psoriatic, and normal skin sections. S aureus strains used in this study were obtained either from cultures of AD skin lesions or from genetically manipulated strains of S aureus that lacked specific microbial surface components recognizing adhesive matrix molecules (MSCRAMMs)--namely, fibronectin-binding protein (Fnbp), fibrinogen-binding protein (Clf), collagen-binding protein (Cna), and their parent strains. In addition, S aureus strains from patients with AD were pretreated with fibronectin or fibrinogen to block MSCRAMM receptors and interfere with binding. RESULTS Under all experimental conditions, binding of S aureus was localized primarily to the stratum corneum. Immunocytochemical staining of AD skin sections showed a redistribution of fibronectin to the cornified layer, an observation not seen in normal skin. S aureus binding to uninvolved AD skin was significantly greater than the binding to uninvolved psoriatic skin (P <.0001) and normal skin (P <.0005). The Fnbp-negative S aureus showed a significant reduction in binding to the AD skin (P <.0001) but not to the psoriatic and normal skin. In the AD skin, a significant reduction in the binding of S aureus was also observed in the Clf-negative strain (P <.0001) but not in the Cna-negative S aureus. Preincubation of S aureus with either fibronectin or fibrinogen also inhibited bacterial binding to AD skin (P <.0001). CONCLUSION These data suggest that fibronectin and fibrinogen--but not collagen--play a major role in the enhanced binding of S aureus to the skin of patients with AD.
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Affiliation(s)
- S H Cho
- Department of Pediatrics, National Jewish Medical and Research Center, Denver. CO 80206, USA
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40
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Tomasini-Johansson BR, Kaufman NR, Ensenberger MG, Ozeri V, Hanski E, Mosher DF. A 49-residue peptide from adhesin F1 of Streptococcus pyogenes inhibits fibronectin matrix assembly. J Biol Chem 2001; 276:23430-9. [PMID: 11323441 DOI: 10.1074/jbc.m103467200] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
F1 is an adhesin of Streptococcus pyogenes which binds the N-terminal 70-kDa region of fibronectin with high affinity. The fibronectin binding region of F1 is comprised of a 43-residue upstream domain and a repeat domain comprised of five tandem 37-residue sequences. We investigated the effects of these domains on the assembly of fibronectin matrix by human dermal fibroblasts, MG63 osteosarcoma cells, or fibroblasts derived from fibronectin-null stem cells. Subequimolar or equimolar concentrations of recombinant proteins containing both the upstream and repeat domains or just the repeat domain enhanced binding of fibronectin or its N-terminal 70-kDa fragment to cell layers; higher concentrations of these recombinant proteins inhibited binding. The enhanced binding did not result in greater matrix assembly and was caused by increased ligand binding to substratum. In contrast, recombinant or synthetic protein containing the 43 residues of the upstream domain and the first 6 residues from the repeat domain exhibited monophasic inhibition with an IC(50) of approximately 10 nm. Truncation of the 49-residue sequence at its N or C terminus caused loss of inhibitory activity. The 49-residue upstream sequence blocked incorporation of both endogenous cellular fibronectin and exogenous plasma fibronectin into extracellular matrix and inhibited binding of 70-kDa fragment to fibronectin-null cells in a fibronectin-free system. Inhibition of matrix assembly by the 49-mer had no effect on cell adhesion to substratum, cell growth, formation of focal contacts, or formation of stress fibers. These results indicate that the 49-residue upstream sequence of F1 binds in an inhibitory mode to N-terminal parts of exogenous and endogenous fibronectin which are critical for fibronectin fibrillogenesis.
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Affiliation(s)
- B R Tomasini-Johansson
- Department of Medicine and the Molecular and Cellular Pharmacology Program, University of Wisconsin, Madison, Wisconsin 53706, USA
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41
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Rice K, Huesca M, Vaz D, McGavin MJ. Variance in fibronectin binding and fnb locus polymorphisms in Staphylococcus aureus: identification of antigenic variation in a fibronectin binding protein adhesin of the epidemic CMRSA-1 strain of methicillin-resistant S. aureus. Infect Immun 2001; 69:3791-9. [PMID: 11349044 PMCID: PMC98394 DOI: 10.1128/iai.69.6.3791-3799.2001] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The fnbA and fnbB genes of Staphylococcus aureus 8325-4 encode fibronectin (Fn) binding proteins FnBPA and FnBPB, which promote adherence to host tissues. Each adhesin contains three copies of a repeated D motif that binds Fn and is a target for vaccine development. In this study, we assess variability within the Fn-binding domain of the FnBP adhesins and evaluate factors that promote variance in Fn binding among clinical isolates. Based on variation in the number of fnb genes or the number of D motifs, we identified five polymorphism groups. S. aureus 8325-4 and 91% of methicillin-resistant S. aureus (MRSA) isolates belong to polymorphism group I, with two fnb genes and three copies of the D motif. Polymorphism group II contained one fnb gene with only two D motifs and was associated with the epidemic CMRSA-4 strain, which exhibited high protease activity and low Fn binding. Polymorphism group III was unique to the epidemic CMRSA-1 strain, defined by the presence of a fourth D motif that exhibited antigenic variation within a conserved sequence that is essential for Fn binding. However, the sequence of the D motifs was otherwise highly conserved among the other polymorphism groups. Variation in Fn binding among MRSA isolates was inversely related to protease activity but not to the number of fnb genes or the number of D motifs. Therefore, the fnb locus is polymorphic in a small number of strains, but this does not contribute to variation in Fn binding. The antigenic variation that was observed only in the epidemic CMRSA-1 strain may have evolved in response to a host immune response encountered during successive cycles of colonization, transmission, and infection in the nosocomial environment.
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Affiliation(s)
- K Rice
- University of Toronto, Department of Laboratory Medicine and Pathobiology, and Sunnybrook and Women's College Health Science Center, Department of Microbiology, Toronto, Ontario M4N 3M5, Canada
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42
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Schwarz-Linek U, Plevin MJ, Pickford AR, Höök M, Campbell ID, Potts JR. Binding of a peptide from aStreptococcus dysgalactiaeMSCRAMM to the N-terminal F1 module pair of human fibronectin involves both modules. FEBS Lett 2001; 497:137-40. [PMID: 11377428 DOI: 10.1016/s0014-5793(01)02418-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Host invasion by a number of pathogenic bacteria such as staphylococci and streptococci involves binding to fibronectin, a ubiquitous extracellular matrix protein. On the bacterial side, host extracellular matrix adherence is mediated by MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) which, in some cases, have been identified to be important virulence factors. In this study we used nuclear magnetic resonance spectroscopy to characterize the interaction of B3, a synthetic peptide derived from an adhesin of Streptococcus dysgalactiae, with the N-terminal module pair 1F12F1 of human fibronectin. 1F12F1 chemical shift changes occurring on formation of the 1F12F1/B3 complex indicate that both modules bind to the peptide and that a similar region of each module is involved. A similar surface of the 4F15F1 module pair had previously been identified as the binding site for a fibronectin-binding peptide from Staphylococcus aureus.
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Affiliation(s)
- U Schwarz-Linek
- Department of Biochemistry, University of Oxford, South Parks Road, UK
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43
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Miyamoto YJ, Wann ER, Fowler T, Duffield E, Höök M, McIntyre BW. Fibronectin binding protein A of Staphylococcus aureus can mediate human T lymphocyte adhesion and coactivation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:5129-38. [PMID: 11290795 DOI: 10.4049/jimmunol.166.8.5129] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The extracellular matrix protein fibronectin (FN) mediates the adhesion of bacteria as well as T lymphocytes. Mammalian cells express integrins alpha(4)beta(1) and alpha(5)beta(1) as the major FN-binding cell surface receptors. Bacteria such as Staphylococcus aureus, also express FN-binding receptors that are important for adherence to host tissue and initiation of infection. The S. aureus FN-binding protein, FnbpA, has been previously identified, and recombinant proteins that correspond to distinct functional regions of this protein have been made. Three recombinant truncated forms of FnbpA, rFnbpA(37-881), rFnbpA(37-605), and rFnbpA(620-881), were examined for effects on in vitro adhesion and coactivation of human T lymphocytes. These proteins, when coimmobilized with anti-CD3 mAb, activated T lymphocyte proliferation. The coactivation signal generated by the rFnbpA proteins required medium containing serum with FN. Furthermore, the costimulatory signal could be restored in FN-depleted serum when the rFnbpAs were preloaded with soluble FN. Monoclonal Ab blocking studies revealed that integrin alpha(5)beta(1) is the major receptor responsible for the rFnbpA costimulatory signal. Shear flow cell detachment assays confirmed that lymphocytes can bind to FN captured by the rFnbpA proteins. These results suggest that the S. aureus rFnbpA can interact with integrin alpha(5)beta(1) via an FN bridge to mediate adhesion and costimulatory signals to T lymphocytes.
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Affiliation(s)
- Y J Miyamoto
- Department of Immunology, University of Texas M. D. Anderson Cancer Center, and Center for Extracellular Matrix Biology, Albert B. Alkek Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX 77030, USA
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44
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Talay SR, Zock A, Rohde M, Molinari G, Oggioni M, Pozzi G, Guzman CA, Chhatwal GS. Co-operative binding of human fibronectin to Sfbl protein triggers streptococcal invasion into respiratory epithelial cells. Cell Microbiol 2000; 2:521-35. [PMID: 11207605 DOI: 10.1046/j.1462-5822.2000.00076.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Streptococcal fibronectin binding protein I (SfbI) mediates adherence to and invasion of Streptococcus pyogenes into human epithelial cells. In this study, we analysed the binding activity of distinct domains of SfbI protein towards its ligand, the extracellular matrix component fibronectin, as well as the biological implication of the binding events during the infection process. By using purified recombinant SfbI derivatives as well as in vivo expressed SfbI domains on the surface of heterologous organism Streptococcus gordonii, we were able to dissociate the two major streptococcal target domains on the human fibronectin molecule. The SfbI repeat region exclusively bound to the 30 kDa N-terminal fragment of fibronectin, whereas the SfbI spacer region exclusively bound to the 45 kDa collagen-binding fragment of fibronectin. In the case of native surface-expressed SfbI protein, an induced fit mode of bacteria-fibronectin interaction was identified. We demonstrate that binding of the 30 kDa fibronectin fragment to the repeat region of SfbI protein co-operatively activates the adjacent SfbI spacer domain to bind the 45 kDa fibronectin fragment. The biological consequence arising from this novel mode of fibronectin targeting was analysed in eukaryotic cell invasion assays. The repeat region of SfbI protein is mediating adherence and constitutes a prerequisite for subsequent invasion, whereas the SfbI spacer domain efficiently triggers the invasion process of streptococci into the eukaryotic cell. Thus, we were able to dissect bacterial adhesion from invasion by manipulating one protein. SfbI protein therefore represents a highly evolved prokaryotic molecule that exploits the host factor fibronectin not only for extracellular targeting but also for its subsequent activation that leads to efficient cellular invasion.
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Affiliation(s)
- S R Talay
- Division of Microbiology, Technical University/GBF-National Research Centre for Biotechnology, Braunschweig, Germany.
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45
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Dziewanowska K, Carson AR, Patti JM, Deobald CF, Bayles KW, Bohach GA. Staphylococcal fibronectin binding protein interacts with heat shock protein 60 and integrins: role in internalization by epithelial cells. Infect Immun 2000; 68:6321-8. [PMID: 11035741 PMCID: PMC97715 DOI: 10.1128/iai.68.11.6321-6328.2000] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We reported previously that internalization of Staphylococcus aureus by nonprofessional phagocytes involves an interaction between fibronectin (Fn) binding protein (FnBP) and the host cell, resulting in signal transduction, tyrosine kinase activity, and cytoskeletal rearrangement (K. Dziewanowska, J. M. Patti, C. F. Deobald, K. W. Bayles, W. R. Trumble, and G. A. Bohach, Infect. Immun. 67:4673-4678, 1999). The goal of the present study was to identify the host molecules responsible for uptake of the organism through an interaction with FnBP. First, Fn was required for internalization. Addition of small amounts of exogenous Fn stimulated the uptake of S. aureus by HEp-2 cells, which are deficient in Fn synthesis. Fn antibodies blocked internalization of the organism by MAC-T cell monolayers, a bovine epithelial cell line which expresses Fn. Second, a monoclonal antibody (MAb) specific for beta(1) integrins dramatically reduced S. aureus invasion, suggesting that the formation of a Fn bridge linking the host cell beta(1) integrin and FnBP precedes internalization. However, ligand blotting of cell membrane proteins with a functional fragment of FnBP consistently identified an additional approximately 55-kDa receptor on both human and bovine epithelial cells. This protein was purified and identified by N-terminal microsequencing as heat shock protein 60 (Hsp60). The interaction between FnBP and Hsp60 also occurred when the whole cells were used. Cell membrane localization of Hsp60 was confirmed by biotinylation with an agent nonpermeable to the cell membrane. Pretreatment of epithelial cells with a MAb specific for eukaryotic Hsp60 significantly reduced internalization of S. aureus. Combined, these results suggest that the FnBP binds directly to both Hsp60 and Fn and is linked to beta(1) integrins through a Fn bridge. The simultaneous involvement of Fn and two host cell ligands, beta(1) integrins and Hsp60, suggests that FnBP is a multifunctional adhesin that mediates internalization in a manner similar to that proposed for OpaA, the Neisseria gonorrhoeae FnBP homolog (J. P. M. van Putten, T. D. Duensing, and R. L. Cole, Mol. Microbiol. 29:369-379, 1998).
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Affiliation(s)
- K Dziewanowska
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844, USA
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Fowler T, Wann ER, Joh D, Johansson S, Foster TJ, Höök M. Cellular invasion by Staphylococcus aureus involves a fibronectin bridge between the bacterial fibronectin-binding MSCRAMMs and host cell beta1 integrins. Eur J Cell Biol 2000; 79:672-9. [PMID: 11089915 DOI: 10.1078/0171-9335-00104] [Citation(s) in RCA: 188] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Although Staphylococcus aureus is primarily considered an extracellular pathogen, recent evidence suggests that this bacterium can invade a variety of nonprofessional phagocytic cells. Here we investigate the early stages of cellular invasion by S. aureus and determine the bacterial and host components that are required for this process. S. aureus expresses two cell surface-associated fibronectin (FN)-binding proteins (FnbpA and FnbpB) that mediate the interaction of the bacteria with both soluble and solid-phase FN in vitro. Using a mutant of S. aureus that lacks the expression of both Fnbps, we show that the expression of either protein is necessary for efficient uptake by the mouse fibroblast line GD25beta1A. Invasion could be inhibited by soluble recombinant proteins encompassing either the FN-binding D repeat region or the A region (and B repeats) of FnbpA, suggesting that the activities of both regions are important in this process. We demonstrate that FN is also required for invasion of this cell line. In the presence of FN-depleted fetal bovine serum, the invasion level was reduced by approximately 40% compared to in the presence of whole fetal bovine serum. Invasion could be further reduced by the addition of anti-mouse FN antibodies to the assay. Finally, we utilize a mutant mouse fibroblast line, which lacks beta1 integrin expression, to demonstrate that host cell beta1 integrins are necessary for efficient cellular invasion. The level of invasion of the mutant cell line GD25 was reduced by approximately 97% compared to the beta1-expressing complemented cell line GD25beta1A. In addition, invasion of the GD25beta1A cell line could be inhibited by an RGD-containing peptide, further implicating a role for integrins in this process. Based on these observations, we put forward a model of S. aureus invasion in which host FN forms a bridge between the bacterial Fnbps and host cell beta1 integrins, leading to bacterial uptake.
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Affiliation(s)
- T Fowler
- Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston 77030, USA
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Wann ER, Gurusiddappa S, Hook M. The fibronectin-binding MSCRAMM FnbpA of Staphylococcus aureus is a bifunctional protein that also binds to fibrinogen. J Biol Chem 2000; 275:13863-71. [PMID: 10788510 DOI: 10.1074/jbc.275.18.13863] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Staphylococcus aureus is an important pathogen capable of causing a wide spectrum of diseases in humans and animals. This bacterium expresses a variety of virulence factors that participate in the process of infection. These include MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) that mediate the adherence of the bacteria to host extracellular matrix components, such as collagen, fibronectin (Fn), and fibrinogen (Fg). Two Fn-binding MSCRAMMs, FnbpA and FnbpB, have been previously identified. The Fn binding activity has been localized to the approximately 40-amino acid residue D repeats in the C-terminal part of these proteins. However, no biological activity has yet been attributed to the N-terminal A regions of these proteins. These regions exhibit substantial amino acid sequence identity to the A regions of other staphylococcal MSCRAMMs, including ClfA, ClfB, and SdrG (Fbe), all of which bind Fg. This raises the question of whether the Fn-binding MSCRAMMs can also bind specifically to Fg. In this report, we show that a recombinant form of the A region of FnbpA does specifically recognize Fg. We localize the binding site in Fg for recombinant FnbpA to the gamma-chain, in particular to the C-terminal residues of this polypeptide, the site also recognized by ClfA. In addition, we demonstrate that recombinant FnbpA can compete with ClfA for binding to both immobilized and soluble Fg. By the use of surface plasmon resonance spectroscopy and fluorescence polarization, we determine the dissociation equilibrium constant for the interaction of recombinant FnbpA with intact immobilized Fg and with a synthetic C-terminal gamma-chain peptide, respectively. Finally, by overexpressing FnbpA in a mutant strain of S. aureus that lacks the expression of both ClfA and ClfB, we show that native FnbpA can mediate the interaction of S. aureus with soluble Fg.
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Affiliation(s)
- E R Wann
- Center for Extracellular Matrix Biology, Department of Biochemistry and Biophysics, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030-3303, USA.
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Huesca M, Sun Q, Peralta R, Shivji GM, Sauder DN, McGavin MJ. Synthetic peptide immunogens elicit polyclonal and monoclonal antibodies specific for linear epitopes in the D motifs of Staphylococcus aureus fibronectin-binding protein, which are composed of amino acids that are essential for fibronectin binding. Infect Immun 2000; 68:1156-63. [PMID: 10678920 PMCID: PMC97261 DOI: 10.1128/iai.68.3.1156-1163.2000] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A fibronectin (Fn)-binding adhesin of Staphylococcus aureus contains three tandem 37- or 38-amino-acid motifs (D1, D2, and D3), which function to bind Fn. Plasma from patients with S. aureus infections contain antibodies that preferentially recognize ligand induced binding sites in the D motifs and do not inhibit Fn binding (F. Casolini, L. Visai, D. Joh, P. G. Conaldi, A. Toniolo, M. Höök, and P. Speziale, Infect. Immun. 66:5433-5442, 1998). To eliminate the influence of Fn binding on antibody development, we used synthetic peptide immunogens D1(21-34) and D3(20-33), which each contain a conserved pattern of amino acids that is essential for Fn binding but which cannot bind Fn without N- or C-terminal extensions. The D3(20-33) immunogen promoted the production of polyclonal antibodies that were 10-fold more effective as inhibitors of Fn-binding to the D3 motif than antibodies obtained by immunizing with an extended peptide D3(16-36), which exhibits functional Fn binding. The D3(20-33) immunogen also facilitated the production of a monoclonal antibody, 9C3, which was highly specific for the epitope SVDFEED, and abolished Fn binding by the D3 motif. When mixed with polyclonal anti-D1(21-34) immunoglobulin G, 70% inhibition of Fn binding to the three tandem D motifs was achieved compared to no more than 30% inhibition with either antibody preparation alone. Therefore, by immunizing with short synthetic peptides that are unable to bind Fn, we have effectively stimulated the production of antibodies specific for epitopes comprised of amino acids that are essential for Fn binding. Although these epitopes occur within a conserved pattern of amino acids that is required for Fn binding, the antibodies recognized specific linear epitope sequences and not a conserved structure common to all repeated motifs.
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Affiliation(s)
- M Huesca
- Division of Microbiology, Sunnybrook and Women's College Health Sciences Centre, North York, Ontario M4N 3M5, Canada
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Cunliffe D, Smart CA, Alexander C, Vulfson EN. Bacterial adhesion at synthetic surfaces. Appl Environ Microbiol 1999; 65:4995-5002. [PMID: 10543814 PMCID: PMC91672 DOI: 10.1128/aem.65.11.4995-5002.1999] [Citation(s) in RCA: 212] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A systematic investigation into the effect of surface chemistry on bacterial adhesion was carried out. In particular, a number of physicochemical factors important in defining the surface at the molecular level were assessed for their effect on the adhesion of Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, and Escherichia coli. The primary experiments involved the grafting of groups varying in hydrophilicity, hydrophobicity, chain length, and chemical functionality onto glass substrates such that the surfaces were homogeneous and densely packed with functional groups. All of the surfaces were found to be chemically well defined, and their measured surface energies varied from 15 to 41 mJ. m(-2). Protein adsorption experiments were performed with (3)H-labelled bovine serum albumin and cytochrome c prior to bacterial attachment studies. Hydrophilic uncharged surfaces showed the greatest resistance to protein adsorption; however, our studies also showed that the effectiveness of poly(ethyleneoxide) (PEO) polymers was not simply a result of its hydrophilicity and molecular weight alone. The adsorption of the two proteins approximately correlated with short-term cell adhesion, and bacterial attachment for L. monocytogenes and E. coli also correlated with the chemistry of the underlying substrate. However, for S. aureus and S. typhimurium a different pattern of attachment occurred, suggesting a dissimilar mechanism of cell attachment, although high-molecular-weight PEO was still the least-cell-adsorbing surface. The implications of this for in vivo attachment of cells suggest that hydrophilic passivating groups may be the best method for preventing cell adsorption to synthetic substrates provided they can be grafted uniformly and in sufficient density at the surface.
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Affiliation(s)
- D Cunliffe
- Macromolecular Science Department, Institute of Food Research, Reading Laboratory, Reading RG6 6BZ, United Kingdom
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Joh D, Wann ER, Kreikemeyer B, Speziale P, Höök M. Role of fibronectin-binding MSCRAMMs in bacterial adherence and entry into mammalian cells. Matrix Biol 1999; 18:211-23. [PMID: 10429941 DOI: 10.1016/s0945-053x(99)00025-6] [Citation(s) in RCA: 207] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Most bacterial infections are initiated by the adherence of microorganisms to host tissues. This process involves the interaction of specific bacterial surface structures, called adhesins, with host components. In this review, we discuss a group of microbial adhesins known as Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) which recognize and bind FN. The interaction of bacteria with FN is believed to contribute significantly to the virulence of a number of microorganisms, including staphylococci and streptococci. Several FN-binding MSCRAMMs of staphylococci and streptococci exhibit a similar structural organization and mechanism of ligand recognition. The ligand-binding domain consists of tandem repeats of a approximately 45 amino acid long unit which bind to the 29-kDa N-terminal region of FN. The binding mechanism is unusual in that the repeat units are unstructured and appear to undergo a conformational change upon ligand binding. Apart from supporting bacterial adherence, FN is also involved in bacterial entry into non-phagocytic mammalian cells. A sandwich model has been proposed in which FN forms a molecular bridge between MSCRAMMs on the bacterial surface and integrins on the host cell. However, the precise mechanism of bacterial invasion and the roles of FN and integrins in this process have yet to be fully elucidated.
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Affiliation(s)
- D Joh
- Center for Extracellular Matrix Biology, Albert B. Alkek Institute of Biosciences and Technology, Texas A&M University System, Houston 77030, USA
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