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Fulton DA, Dura G, Peters DT. The polymer and materials science of the bacterial fimbriae Caf1. Biomater Sci 2023; 11:7229-7246. [PMID: 37791425 PMCID: PMC10628683 DOI: 10.1039/d3bm01075a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/22/2023] [Indexed: 10/05/2023]
Abstract
Fimbriae are long filamentous polymeric protein structures located upon the surface of bacteria. Often implicated in pathogenicity, the biosynthesis and function of fimbriae has been a productive topic of study for many decades. Evolutionary pressures have ensured that fimbriae possess unique structural and mechanical properties which are advantageous to bacteria. These properties are also difficult to engineer with well-known synthetic and natural fibres, and this has raised an intriguing question: can we exploit the unique properties of bacterial fimbriae in useful ways? Initial work has set out to explore this question by using Capsular antigen fragment 1 (Caf1), a fimbriae expressed naturally by Yersina pestis. These fibres have evolved to 'shield' the bacterium from the immune system of an infected host, and thus are rather bioinert in nature. Caf1 is, however, very amenable to structural mutagenesis which allows the incorporation of useful bioactive functions and the modulation of the fibre's mechanical properties. Its high-yielding recombinant synthesis also ensures plentiful quantities of polymer are available to drive development. These advantageous features make Caf1 an archetype for the development of new polymers and materials based upon bacterial fimbriae. Here, we cover recent advances in this new field, and look to future possibilities of this promising biopolymer.
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Affiliation(s)
- David A Fulton
- Chemistry-School of Natural Science and Environmental Sciences, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK.
| | - Gema Dura
- Chemistry-School of Natural Science and Environmental Sciences, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK.
- Departamento de Química Inorgánica Orgánica y Bioquímica Universidad de Castilla-La Mancha Facultad de Ciencias y Tecnologías Químicas-IRICAAvda, C. J. Cela, 10, Ciudad Real 13071, Spain
| | - Daniel T Peters
- Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
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Böhning J, Dobbelstein AW, Sulkowski N, Eilers K, von Kügelgen A, Tarafder AK, Peak-Chew SY, Skehel M, Alva V, Filloux A, Bharat TAM. Architecture of the biofilm-associated archaic Chaperone-Usher pilus CupE from Pseudomonas aeruginosa. PLoS Pathog 2023; 19:e1011177. [PMID: 37058467 PMCID: PMC10104325 DOI: 10.1371/journal.ppat.1011177] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 02/03/2023] [Indexed: 04/15/2023] Open
Abstract
Chaperone-Usher Pathway (CUP) pili are major adhesins in Gram-negative bacteria, mediating bacterial adherence to biotic and abiotic surfaces. While classical CUP pili have been extensively characterized, little is known about so-called archaic CUP pili, which are phylogenetically widespread and promote biofilm formation by several human pathogens. In this study, we present the electron cryomicroscopy structure of the archaic CupE pilus from the opportunistic human pathogen Pseudomonas aeruginosa. We show that CupE1 subunits within the pilus are arranged in a zigzag architecture, containing an N-terminal donor β-strand extending from each subunit into the next, where it is anchored by hydrophobic interactions, with comparatively weaker interactions at the rest of the inter-subunit interface. Imaging CupE pili on the surface of P. aeruginosa cells using electron cryotomography shows that CupE pili adopt variable curvatures in response to their environment, which might facilitate their role in promoting cellular attachment. Finally, bioinformatic analysis shows the widespread abundance of cupE genes in isolates of P. aeruginosa and the co-occurrence of cupE with other cup clusters, suggesting interdependence of cup pili in regulating bacterial adherence within biofilms. Taken together, our study provides insights into the architecture of archaic CUP pili, providing a structural basis for understanding their role in promoting cellular adhesion and biofilm formation in P. aeruginosa.
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Affiliation(s)
- Jan Böhning
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Adrian W. Dobbelstein
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Nina Sulkowski
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Kira Eilers
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Andriko von Kügelgen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Abul K. Tarafder
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Sew-Yeu Peak-Chew
- Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Mark Skehel
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Vikram Alva
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Alain Filloux
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Tanmay A. M. Bharat
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
- Structural Studies Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
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Peters DT, Reifs A, Alonso-Caballero A, Madkour A, Waller H, Kenny B, Perez-Jimenez R, Lakey JH. Unraveling the molecular determinants of the anti-phagocytic protein cloak of plague bacteria. PLoS Pathog 2022; 18:e1010447. [PMID: 35358289 PMCID: PMC9004762 DOI: 10.1371/journal.ppat.1010447] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 04/12/2022] [Accepted: 03/16/2022] [Indexed: 12/03/2022] Open
Abstract
The pathogenic bacterium Yersina pestis is protected from macrophage engulfment by a capsule like antigen, F1, formed of long polymers of the monomer protein, Caf1. However, despite the importance of this pathogen, the mechanism of protection was not understood. Here we demonstrate how F1 protects the bacteria from phagocytosis. First, we show that Escherichia coli expressing F1 showed greatly reduced adherence to macrophages. Furthermore, the few cells that did adhere remained on the macrophage surface and were not engulfed. We then inserted, by mutation, an “RGDS” integrin binding motif into Caf1. This did not change the number of cells adhering to macrophages but increased the fraction of adherent cells that were engulfed. Therefore, F1 protects in two separate ways, reducing cell adhesion, possibly by acting as a polymer brush, and hiding innate receptor binding sites needed for engulfment. F1 is very robust and we show that E. coli expressing weakened mutant polymers are engulfed like the RGDS mutant. This suggests that innate attachment sites on the native cell surface are exposed if F1 is weakened. Single-molecule force spectroscopy (SMFS) experiments revealed that wild-type F1 displays a very high mechanical stability of 400 pN. However, the mechanical resistance of the destabilised mutants, that were fully engulfed, was only 20% weaker. By only marginally exceeding the mechanical force applied to the Caf1 polymer during phagocytosis it may be that the exceptional tensile strength evolved to resist the forces applied at this stage of engulfment. Macrophages, a type of white blood cell, form an important element of our immune defence. They interrogate other cells’ surfaces for molecular clues and ingest those presenting a threat in a process known as phagocytosis. Not surprisingly, pathogenic bacteria have developed ways to evade this fate. The plague bacterium, Yersinia pestis, produces the long polymeric F1 coat protein which enables it to avoid ingestion, but the mechanism was unclear. We show that equipping Escherichia coli cells with an F1 coat protected them from phagocytosis by two separate mechanisms, reducing contact with the macrophage surface and hiding the signals that tell the macrophages they are targets. F1 is also a very stable protein polymer and using single molecule force spectroscopy we showed it also has a very high resistance to pulling forces. Surprisingly, mutations which reduced this by only 20% caused adherent bacteria to be fully ingested, indicating that cells are subject to significant forces prior to recognition and ingestion. Thus, F1 has evolved three notable properties (i) physical; creation of a hydrated polymer brush to inhibit surface interactions, (ii) chemical; absence of molecular recognition clues needed for engulfment and (iii) mechanical; strength that maintains the camouflage layer during surface stretching.
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Affiliation(s)
- Daniel T. Peters
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | | | - Azzeldin Madkour
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Helen Waller
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Brendan Kenny
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Raul Perez-Jimenez
- CIC nanoGUNE BRTA, San Sebastian, Spain
- Ikerbasque Foundation for Science, Bilbao, Spain
| | - Jeremy H. Lakey
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- * E-mail:
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Solovyova AS, Peters DT, Dura G, Waller H, Lakey JH, Fulton DA. Probing the oligomeric re-assembling of bacterial fimbriae in vitro: a small-angle X-ray scattering and analytical ultracentrifugation study. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2021; 50:597-611. [PMID: 33948690 PMCID: PMC8190007 DOI: 10.1007/s00249-021-01543-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 04/14/2021] [Accepted: 04/20/2021] [Indexed: 02/07/2023]
Abstract
Capsular antigen fragment 1 (Caf1) is an oligomeric protein consisting of 15 kDa monomeric subunits that are non-covalently linked through exceptionally strong and kinetically inert interactions into a linear polymer chain. It has been shown that after its thermal depolymerisation into unfolded monomeric subunits, Caf1 is able to efficiently repolymerise in vitro to reform its polymeric structure. However, little is known about the nature of the repolymerisation process. An improved understanding of this process will lead to the development of methods to better control the lengths of the repolymerised species, and ultimately, to better design of the properties of Caf1-based materials. Here we utilize small-angle X-ray scattering to estimate the size of Caf1 polymers during the first 24 h of the re-polymerisation process. Analytical ultracentrifugation measurements were also used to investigate the process post-24 h, where the rate of repolymerisation becomes considerably slower. Results show that in vitro polymerisation proceeds in a linear manner with no evidence observed for the formation of a lateral polymer network or uncontrolled aggregates. The rate of Caf1 in vitro repolymerisation was found to be concentration-dependent. Importantly, the rate of polymer growth was found to be relatively fast over the first few hours, before continuing at a dramatically slower rate. This observation is not consistent with the previously proposed step-growth mechanism of in vitro polymerisation of Caf1, where a linear increase in polymer length would be expected with time. We speculate how our observations may support the idea that the polymerisation process may be occurring at the ends of the chains with monomers adding sequentially. Our findings will contribute towards the development of new biomaterials for 3D cell culture and bio-printing.
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Affiliation(s)
- Alexandra S Solovyova
- Proteome and Protein Analysis, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK.
| | - Daniel T Peters
- Biosciences Institute, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - Gema Dura
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK.,Departamento de Química Inorgánica, Orgánica y Bioquímica, Universidad de Castilla-La Mancha, Facultad de Ciencias yTecnologías Químicas-IRICA, Avda. C. J. Cela, 10, 13071, Ciudad Real, Spain
| | - Helen Waller
- Biosciences Institute, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - Jeremy H Lakey
- Biosciences Institute, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - David A Fulton
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK.
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Dura G, Crespo-Cuadrado M, Waller H, Peters DT, Ferreira AM, Lakey JH, Fulton DA. Hydrogels of engineered bacterial fimbriae can finely tune 2D human cell culture. Biomater Sci 2021; 9:2542-2552. [PMID: 33571331 DOI: 10.1039/d0bm01966f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Demand continues to grow for biomimetic materials able to create well-defined environments for modulating the behaviour of living cells in culture. Here, we describe hydrogels based upon the polymeric bacterial fimbriae protein capsular antigen fragment 1 (Caf1) that presents tunable biological properties for enhanced tissue cell culture applications. We demonstrate how Caf1 hydrogels can regulate cellular functions such as spreading, proliferation and matrix deposition of human dermal fibroblast cells (hDFBs). Caf1 hydrogels exploring a range of mechanical properties were prepared using copolymers featuring controlled compositions of inert wild-type Caf1 subunits and a mutant subunit displaying the RGDS peptide motif. The hydrogels showed excellent cytocompatibility with hDFBs and the ability to modulate both cell morphology and matrix deposition. Interestingly, Caf1 hydrogels displaying faster stress relaxation were demonstrated to show the highest metabolic activities of growing cells in comparison with other Caf1 hydrogel formulations. The stiffest Caf1 hydrogel impacted cellular morphology, inducing alignment of the cells. This work is significant as it clearly indicates that Caf1-based hydrogels offer tuneable biochemical and mechanical substrates conditions suitable for cell culture applications.
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Affiliation(s)
- Gema Dura
- Chemical Nanoscience Laboratory, Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK.
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Dura G, Peters DT, Waller H, Yemm AI, Perkins ND, Ferreira AM, Crespo-Cuadrado M, Lakey JH, Fulton DA. A Thermally Reformable Protein Polymer. Chem 2020. [DOI: 10.1016/j.chempr.2020.09.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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De Plano LM, Carnazza S, Franco D, Rizzo MG, Conoci S, Petralia S, Nicoletti A, Zappia M, Campolo M, Esposito E, Cuzzocrea S, Guglielmino SPP. Innovative IgG Biomarkers Based on Phage Display Microbial Amyloid Mimotope for State and Stage Diagnosis in Alzheimer's Disease. ACS Chem Neurosci 2020; 11:1013-1026. [PMID: 32176482 PMCID: PMC7997372 DOI: 10.1021/acschemneuro.9b00549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
![]()
An
innovative approach to identify new conformational antigens
of Aβ1–42 recognized by IgG autoantibodies
as biomarkers of state and stage in Alzheimer’s disease (AD)
patients is described. In particular, through the use of bioinformatics
modeling, conformational similarities between several Aβ1–42 forms and other amyloid-like proteins with F1 capsular
antigen (Caf1) of Yersinia pestis were first found.
pVIII M13 phage display libraries were then screened against YPF19,
anti-Caf1 monoclonal antibody, and IgGs of AD patients, in alternate
biopanning cycles of a so-called “double binding” selection.
From the selected phage clones, one, termed 12III1, was found to be
able to prevent in vitro Aβ1–42-induced cytotoxicity in SH-SY5Y cells, as well as to promote disaggregation
of preformed fibrils, to a greater extent with respect to wild-type
phage (pC89). IgG levels detected by 12III1 provided a significant
level of discrimination between diseased and nondemented subjects,
as well as a good correlation with the state progression of the disease.
These results give significant impact in AD state and stage diagnosis,
paving the way for the development not only for an innovative blood
diagnostic assay for AD precise diagnosis, progressive clinical assessment,
and screening but also for new effective treatments.
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Affiliation(s)
- Laura M. De Plano
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Santina Carnazza
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Domenico Franco
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Maria Giovanna Rizzo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Sabrina Conoci
- STmicroelectronics, Stradale Primosole, 50, 95121 Catania, Italy
- Distretto Tecnologico Micro e Nano Sistemi Sicilia, Strada VII-Zona Industriale, 95121 Catania, Italy
| | | | - Alessandra Nicoletti
- Neurology Clinic, Department “G.F. Ingrassia”, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123 Catania, Italy
| | - Mario Zappia
- Neurology Clinic, Department “G.F. Ingrassia”, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123 Catania, Italy
| | - Michela Campolo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Emanuela Esposito
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Salvatore Cuzzocrea
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Salvatore P. P. Guglielmino
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
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Peters DT, Waller H, Birch MA, Lakey JH. Engineered mosaic protein polymers; a simple route to multifunctional biomaterials. J Biol Eng 2019; 13:54. [PMID: 31244892 PMCID: PMC6582577 DOI: 10.1186/s13036-019-0183-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 06/03/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Engineered living materials (ELMs) are an exciting new frontier, where living organisms create highly functional materials. In particular, protein ELMs have the advantage that their properties can be manipulated via simple molecular biology. Caf1 is a protein ELM that is especially attractive as a biomaterial on account of its unique combination of properties: bacterial cells export it as a massive, modular, non-covalent polymer which is resistant to thermal and chemical degradation and free from animal material. Moreover, it is biologically inert, allowing the bioactivity of each 15 kDa monomeric Caf1 subunit to be specifically engineered by mutagenesis and co-expressed in the same Escherichia coli cell to produce a mixture of bioactive Caf1 subunits. RESULTS Here, we show by gel electrophoresis and transmission electron microscopy that the bacterial cells combine these subunits into true mosaic heteropolymers. By combining two separate bioactive motifs in a single mosaic polymer we demonstrate its utility by stimulating the early stages of bone formation by primary human bone marrow stromal cells. Finally, using a synthetic biology approach, we engineer a mosaic of three components, demonstrating that Caf1 complexity depends solely upon the variety of monomers available. CONCLUSIONS These results demonstrate the utility of engineered Caf1 mosaic polymers as a simple route towards the production of multifunctional biomaterials that will be useful in biomedical applications such as 3D tissue culture and wound healing. Additionally, in situ Caf1 producing cells could create complex bacterial communities for biotechnology. GRAPHICAL ABSTRACT
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Affiliation(s)
- Daniel T. Peters
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Helen Waller
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Mark A. Birch
- Division of Trauma and Orthopaedic Surgery, Department of Surgery, University of Cambridge, Cambridge, UK
| | - Jeremy H. Lakey
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK
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Cerofolini L, Giuntini S, Ravera E, Luchinat C, Berti F, Fragai M. Structural characterization of a protein adsorbed on aluminum hydroxide adjuvant in vaccine formulation. NPJ Vaccines 2019; 4:20. [PMID: 31149351 PMCID: PMC6538755 DOI: 10.1038/s41541-019-0115-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 05/03/2019] [Indexed: 12/11/2022] Open
Abstract
The heterogeneous composition of vaccine formulations and the relatively low concentration make the characterization of the protein antigens extremely challenging. Aluminum-containing adjuvants have been used to enhance the immune response of several antigens over the last 90 years and still remain the most commonly used. Here, we show that solid-state NMR and isotope labeling methods can be used to characterize the structural features of the protein antigen component of vaccines and to investigate the preservation of the folding state of proteins adsorbed on Alum hydroxide matrix, providing the way to identify the regions of the protein that are mainly affected by the presence of the inorganic matrix. l-Asparaginase from E. coli has been used as a pilot model of protein antigen. This methodology can find application in several steps of the vaccine development pipeline, from the antigen optimization, through the design of vaccine formulation, up to stability studies and manufacturing process.
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Affiliation(s)
- Linda Cerofolini
- 1Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Stefano Giuntini
- 2Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Enrico Ravera
- 1Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.,2Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Claudio Luchinat
- 1Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.,2Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Francesco Berti
- Technical R&D, GSK Vaccines, Via Fiorentina 1, 53100 Siena, Italy
| | - Marco Fragai
- 1Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.,2Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
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Al-Jawdah AD, Ivanova IG, Waller H, Perkins ND, Lakey JH, Peters DT. Induction of the immunoprotective coat of Yersinia pestis at body temperature is mediated by the Caf1R transcription factor. BMC Microbiol 2019; 19:68. [PMID: 30922226 PMCID: PMC6440114 DOI: 10.1186/s12866-019-1444-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 03/25/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Thermal regulation of gene expression occurs in many microorganisms, and is mediated via several typical mechanisms. Yersinia pestis is the causative agent of the plague and spreads by zoonotic transfer from fleas to mammalian blood with a concomitant rapid temperature change, from ambient to 37 °C, which induces the expression of capsular antigen (Caf1) that inhibits phagocytosis. Caf1 is formed into long polymeric fimbriae by a periplasmic chaperone (Caf1M) and outer membrane usher (Caf1A). All three are encoded on an operon regulated by an AraC-type transcription factor Caf1R. The aim of this study was to determine the role of Caf1R in the thermal control of caf1 operon gene expression. RESULTS PCR analysis of cDNA demonstrated that the genes of the operon are transcribed as a single polycistronic mRNA. Bioinformatic analysis, supported by deletion mutagenesis, then revealed a region containing the promoter of this polycistronic transcript that was critical for Caf1 protein expression. Caf1R was found to be essential for Caf1 protein production. Finally, RT-PCR analysis and western blot experiments showed large, Caf1R dependent increases in caf1 operon transcripts upon a shift in temperature from 25 °C to 35 °C. CONCLUSIONS The results show that thermal control of Caf1 polymer production is established at the transcriptional level, in a Caf1R dependent manner. This gives us new insights into how a virulent pathogen evades destruction by the immune system by detecting and responding to environmental changes.
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Affiliation(s)
- Abdulmajeed D Al-Jawdah
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Iglika G Ivanova
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Helen Waller
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Neil D Perkins
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Jeremy H Lakey
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Daniel T Peters
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, UK.
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Tuneable hydrogels of Caf1 protein fibers. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 93:88-95. [PMID: 30274124 DOI: 10.1016/j.msec.2018.07.063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 07/12/2018] [Accepted: 07/23/2018] [Indexed: 01/20/2023]
Abstract
Capsular antigen fraction 1 (Caf1) is a robust polymeric protein forming a protective layer around the bacterium Yersinia pestis. Occurring as ≈1 μm polymeric fibers, it shares its immunoglobulin-like fold with the majority of mammalian extracellular proteins such as fibronectin and this structural similarity suggests that this unusual polymer could form useful mimics of the extracellular matrix. Driven by the pressing need for reliable animal-free 3D cell culture environments, we showed previously that recombinant Caf1 produced in Escherichia coli can be engineered to include bioactive peptides, which influence cell behavior. Here, we demonstrate that through chemical crosslinking with a small palette of PEG-based crosslinkers, Caf1-based hydrogels can be prepared displaying a wide range of mechanical and morphological properties that were studied by rheology, compressive testing, SDS-PAGE and scanning electron microscopy. By varying the Caf1 protein concentration, viscoelasticity and stiffness (~11-2300 Pa) are reproducibly tunable to match natural and commercial 3D gels. Hydrogel porosity and swelling ratios were found to be defined by crosslinker architecture and concentration. Finally the hydrogels, which are 95-99% water, were shown to retain the high stability of the native Caf1 protein in a range of aqueous conditions, including extended immersion in cell culture media. The unusual Caf1 polymer thus offers the possibility of presenting bioactive protein subunits in a precisely tuneable hydrogel for use in cell culture and drug delivery applications.
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Ulusu Y, Dura G, Waller H, Benning MJ, Fulton DA, Lakey JH, Peters DT. Thermal stability and rheological properties of the ‘non-stick’ Caf1 biomaterial. Biomed Mater 2017. [DOI: 10.1088/1748-605x/aa7a89] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Roque AI, Soliakov A, Birch MA, Philips SR, Shah DSH, Lakey JH. Reversible non-stick behaviour of a bacterial protein polymer provides a tuneable molecular mimic for cell and tissue engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:2704-9, 2616. [PMID: 24623384 PMCID: PMC4112846 DOI: 10.1002/adma.201304645] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 02/12/2014] [Indexed: 06/03/2023]
Abstract
Yersina pestis, the bubonic plague bacterium, is coated with a polymeric protein hydrogel for protection from host defences. The protein, which is robust and non-stick, resembles structures found in many eukaryotic extracellular-matrix proteins. Cells grown on the natural polymer cannot adhere and grow poorly; however, when cell-adhesion motifs are inserted into the protein, the cells proliferate.
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Affiliation(s)
- Ana I. Roque
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneNE2 4HHUnited Kingdom
| | - Andrei Soliakov
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneNE2 4HHUnited Kingdom
| | - Mark A. Birch
- Institute for Cellular MedicineNewcastle UniversityNewcastle upon TyneNE2 4HHUnited Kingdom
| | - Sion R. Philips
- Orla Protein Technologies LtdInternational Centre for LifeTimes SquareNewcastle upon TyneNE1 4EPUK
| | - Deepan S. H. Shah
- Orla Protein Technologies LtdInternational Centre for LifeTimes SquareNewcastle upon TyneNE1 4EPUK
| | - Jeremy H. Lakey
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneNE2 4HHUnited Kingdom
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Increasing the potency of an alhydrogel-formulated anthrax vaccine by minimizing antigen-adjuvant interactions. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1659-68. [PMID: 23986317 DOI: 10.1128/cvi.00320-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aluminum salts are the most widely used vaccine adjuvants, and phosphate is known to modulate antigen-adjuvant interactions. Here we report an unexpected role for phosphate buffer in an anthrax vaccine (SparVax) containing recombinant protective antigen (rPA) and aluminum oxyhydroxide (AlOH) adjuvant (Alhydrogel). Phosphate ions bind to AlOH to produce an aluminum phosphate surface with a reduced rPA adsorption coefficient and binding capacity. However, these effects continued to increase as the free phosphate concentration increased, and the binding of rPA changed from endothermic to exothermic. Crucially, phosphate restored the thermostability of bound rPA so that it resembled the soluble form, even though it remained tightly bound to the surface. Batches of vaccine with either 0.25 mM (subsaturated) or 4 mM (saturated) phosphate were tested in a disease model at batch release, which showed that the latter was significantly more potent. Both formulations retained their potency for 3 years. The strongest aluminum adjuvant effects are thus likely to be via weakly attached or easily released native-state antigen proteins.
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Cao L, Lim T, Jun S, Thornburg T, Avci R, Yang X. Vulnerabilities in Yersinia pestis caf operon are unveiled by a Salmonella vector. PLoS One 2012; 7:e36283. [PMID: 22558420 PMCID: PMC3340336 DOI: 10.1371/journal.pone.0036283] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 03/28/2012] [Indexed: 11/18/2022] Open
Abstract
During infection, Yersinia pestis uses its F1 capsule to enhance survival and cause virulence to mammalian host. Since F1 is produced in large quantities and secreted into the host tissues, it also serves as a major immune target. To hold this detrimental effect under proper control, Y. pestis expresses the caf operon (encoding the F1 capsule) in a temperature-dependent manner. However, additional properties of the caf operon limit its expression. By overexpressing the caf operon in wild-type Salmonella enterica serovar Typhimurium under a potent promoter, virulence of Salmonella was greatly attenuated both in vitro and in vivo. In contrast, expression of the caf operon under the regulation of its native promoter exhibited negligible impairment of Salmonellae virulence. In-depth investigation revealed all individual genes in the caf operon attenuated Salmonella when overexpressed. The deleterious effects of caf operon and the caf individual genes were further confirmed when they were overexpressed in Y. pestis KIM6+. This study suggests that by using a weak inducible promoter, the detrimental effects of the caf operon are minimally manifested in Y. pestis. Thus, through tight regulation of the caf operon, Y. pestis precisely balances its capsular anti-phagocytic properties with the detrimental effects of caf during interaction with mammalian host.
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Affiliation(s)
- Ling Cao
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Timothy Lim
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - SangMu Jun
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Theresa Thornburg
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Recep Avci
- Imaging and Chemical Analysis Laboratory, Department of Physics, Montana State University, Bozeman, Montana, United States of America
| | - Xinghong Yang
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- * E-mail:
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Fimbrial Polyadhesins: Anti-immune Armament of Yersinia. ADVANCES IN YERSINIA RESEARCH 2012; 954:183-201. [DOI: 10.1007/978-1-4614-3561-7_24] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Soliakov A, Kelly IF, Lakey JH, Watkinson A. Anthrax sub-unit vaccine: the structural consequences of binding rPA83 to Alhydrogel®. Eur J Pharm Biopharm 2011; 80:25-32. [PMID: 21964315 DOI: 10.1016/j.ejpb.2011.09.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 09/09/2011] [Accepted: 09/15/2011] [Indexed: 12/31/2022]
Abstract
An anthrax sub-unit vaccine, comprising recombinant Protective Antigen (rPA83) and aluminium hydroxide adjuvant (Alhydrogel®) is currently being developed. Here, a series of biophysical techniques have been applied to free and adjuvant bound antigen. Limited proteolysis and fluorescence identified no changes in rPA83 tertiary structure following binding to Alhydrogel and the bound rPA83 retained two structurally important calcium ions. For adsorbed rPA83, differential scanning calorimetry revealed a small reduction in unfolding temperature but a large decrease in unfolding enthalpy whilst urea unfolding demonstrated unchanged stability but a loss of co-operativity. Overall, these results demonstrate that interactions between rPA83 and Alhydrogel have a minimal effect on the folded protein structure and suggest that antigen destabilisation is not a primary mechanism of Alhydrogel adjuvancy. This study also shows that informative structural characterisation is possible for adjuvant bound sub-unit vaccines.
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Affiliation(s)
- Andrei Soliakov
- Institute for Cell and Molecular Sciences, Newcastle University, Newcastle-upon-Tyne, UK
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Harris JR, Soliakov A, Lewis RJ, Depoix F, Watkinson A, Lakey JH. Alhydrogel® adjuvant, ultrasonic dispersion and protein binding: a TEM and analytical study. Micron 2011; 43:192-200. [PMID: 21831642 DOI: 10.1016/j.micron.2011.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 07/10/2011] [Accepted: 07/11/2011] [Indexed: 01/25/2023]
Abstract
Aluminium-based vaccine adjuvants have been in use since the 1920s. Aluminium hydroxide (alum) that is the chemical basis of Alhydrogel, a widely used adjuvant, is a colloid that binds proteins to the particular surface for efficient presentation to the immune system during the vaccination process. Using conventional TEM and cryo-TEM we have shown that Alhydrogel can be finely dispersed by ultrasonication of the aqueous suspension. Clusters of ultrasonicated aluminium hydroxide micro-fibre crystals have been produced (∼ 10-100 nm), that are significantly smaller than those present the untreated Alhydrogel (∼ 2-12 μm). However, even prolonged ultrasonication did not produce a homogenous suspension of single aluminium hydroxide micro-fibres. The TEM images of unstained and negatively stained air-dried Alhydrogel are very similar to those obtained by cryo-electron microscopy. Visualization of protein on the surface of the finely dispersed Alhydrogel by TEM is facilitated by prior ultrasonication. Several examples are given, including some of medical relevance, using proteins of widely ranging molecular mass and oligomerization state. Even with the smaller mass proteins, their presence on the Alhydrogel surface can be readily defined by TEM. It has been found that low quantities of protein tend to cross-link and aggregate the small Alhydogel clusters, in a more pronounced manner than high protein concentrations. This indicates that complete saturation of the available Alhydrogel surface with protein may be achieved, with minimal cross-linkage, and future exploitation of this treatment of Alhydrogel is likely to be of immediate value for more efficient vaccine production.
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Affiliation(s)
- J Robin Harris
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
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