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Batani G, Vezzani G, Lashchuk S, Allaoui A, Cardamone D, Raso MM, Boero E, Roscioli E, Ridelfi M, Gasperini G, Pizza M, Rossi O, Berlanda Scorza F, Micoli F, Rappuoli R, Sala C. Development of a visual Adhesion/Invasion Inhibition Assay to assess the functionality of Shigella-specific antibodies. Front Immunol 2024; 15:1374293. [PMID: 38680489 PMCID: PMC11045934 DOI: 10.3389/fimmu.2024.1374293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 04/01/2024] [Indexed: 05/01/2024] Open
Abstract
Introduction Shigella is the etiologic agent of a bacillary dysentery known as shigellosis, which causes millions of infections and thousands of deaths worldwide each year due to Shigella's unique lifestyle within intestinal epithelial cells. Cell adhesion/invasion assays have been extensively used not only to identify targets mediating host-pathogen interaction, but also to evaluate the ability of Shigella-specific antibodies to reduce virulence. However, these assays are time-consuming and labor-intensive and fail to assess differences at the single-cell level. Objectives and methods Here, we developed a simple, fast and high-content method named visual Adhesion/Invasion Inhibition Assay (vAIA) to measure the ability of anti-Shigellaantibodies to inhibit bacterial adhesion to and invasion of epithelial cells by using the confocal microscope Opera Phenix. Results We showed that vAIA performed well with a pooled human serum from subjects challenged with S. sonnei and that a specific anti-IpaD monoclonal antibody effectively reduced bacterial virulence in a dose-dependent manner. Discussion vAIA can therefore inform on the functionality of polyclonal and monoclonal responses thereby supporting the discovery of pathogenicity mechanisms and the development of candidate vaccines and immunotherapies. Lastly, this assay is very versatile and may be easily applied to other Shigella species or serotypes and to different pathogens.
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Affiliation(s)
- Giampiero Batani
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Giacomo Vezzani
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Sabrina Lashchuk
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Abdelmounaaim Allaoui
- The Microbiology Laboratory, University Mohammed VI Polytechnic, Ben, Guerir, Morocco
| | - Dario Cardamone
- Data Science for Health Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | | | - Elena Boero
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Emanuele Roscioli
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Matteo Ridelfi
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Gianmarco Gasperini
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Mariagrazia Pizza
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Omar Rossi
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | | | - Francesca Micoli
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | | | - Claudia Sala
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
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Newman KE, Tindall SN, Mader SL, Khalid S, Thomas GH, Van Der Woude MW. A novel fold for acyltransferase-3 (AT3) proteins provides a framework for transmembrane acyl-group transfer. eLife 2023; 12:e81547. [PMID: 36630168 PMCID: PMC9833829 DOI: 10.7554/elife.81547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 12/04/2022] [Indexed: 01/12/2023] Open
Abstract
Acylation of diverse carbohydrates occurs across all domains of life and can be catalysed by proteins with a membrane bound acyltransferase-3 (AT3) domain (PF01757). In bacteria, these proteins are essential in processes including symbiosis, resistance to viruses and antimicrobials, and biosynthesis of antibiotics, yet their structure and mechanism are largely unknown. In this study, evolutionary co-variance analysis was used to build a computational model of the structure of a bacterial O-antigen modifying acetyltransferase, OafB. The resulting structure exhibited a novel fold for the AT3 domain, which molecular dynamics simulations demonstrated is stable in the membrane. The AT3 domain contains 10 transmembrane helices arranged to form a large cytoplasmic cavity lined by residues known to be essential for function. Further molecular dynamics simulations support a model where the acyl-coA donor spans the membrane through accessing a pore created by movement of an important loop capping the inner cavity, enabling OafB to present the acetyl group close to the likely catalytic resides on the extracytoplasmic surface. Limited but important interactions with the fused SGNH domain in OafB are identified, and modelling suggests this domain is mobile and can both accept acyl-groups from the AT3 and then reach beyond the membrane to reach acceptor substrates. Together this new general model of AT3 function provides a framework for the development of inhibitors that could abrogate critical functions of bacterial pathogens.
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Affiliation(s)
- Kahlan E Newman
- School of Chemistry, University of SouthamptonSouthamptonUnited Kingdom
| | - Sarah N Tindall
- Department of Biology and the York Biomedical Research Institute, University of YorkYorkUnited Kingdom
| | - Sophie L Mader
- Department of Biochemistry, University of OxfordOxfordUnited Kingdom
| | - Syma Khalid
- Department of Biochemistry, University of OxfordOxfordUnited Kingdom
| | - Gavin H Thomas
- Department of Biology and the York Biomedical Research Institute, University of YorkYorkUnited Kingdom
| | - Marjan W Van Der Woude
- Hull York Medical School and the York Biomedical Research Institute, University of YorkYorkUnited Kingdom
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3
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Huan YW, Fa-Arun J, Wang B. The Role of O-antigen in P1 Transduction of Shigella flexneri and Escherichia coli with its Alternative S' Tail Fibre. J Mol Biol 2022; 434:167829. [PMID: 36116540 DOI: 10.1016/j.jmb.2022.167829] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/03/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022]
Abstract
Enterobacteria phage P1 expresses two types of tail fibre, S and S'. Despite the wide usage of phage P1 for transduction, the host range and the receptor for its alternative S' tail fibre was never determined. Here, a ΔS-cin Δpac E. coli P1 lysogenic strain was generated to allow packaging of phagemid DNA into P1 phage having either S or S' tail fibre. P1(S') could transduce phagemid DNA into Shigella flexneri 2a 2457O, Shigella flexneri 5a M90T and Escherichia coli O3 efficiently. Mutational analysis of the O-antigen assembly genes and LPS inhibition assays indicated that P1(S') transduction requires at least one O-antigen unit. E. coli O111:B4 LPS produced a high neutralising effect against P1(S') transduction, indicating that this E. coli strain could be susceptible to P1(S')-mediated transduction. Mutations in the O-antigen modification genes of S. flexneri 2a 2457O and S. flexneri 5a M90T did not cause significant changes to P1(S') transduction efficiency. A higher transduction efficiency of P1(S') improved the delivery of a cas9 antimicrobial phagemid into both S. flexneri 2457O and M90T. These findings provide novel insights into P1 tropism-switching, by identifying the bacterial strains which are susceptible to P1(S')-mediated transduction, as well as demonstrating its potential for delivering a DNA sequence-specific Cas9 antimicrobial into clinically relevant S. flexneri.
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Affiliation(s)
- Yang W Huan
- Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Jidapha Fa-Arun
- Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Baojun Wang
- College of Chemical and Biological Engineering & ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, China; Research Centre of Biological Computation, Zhejiang Laboratory, Hangzhou 311100, China.
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Furevi A, Udekwu KI, Widmalm G. Structural elucidation of the O-antigen polysaccharide from Escherichia coli O125ac and biosynthetic aspects thereof. Glycobiology 2022; 32:1089-1100. [PMID: 36087289 PMCID: PMC9680116 DOI: 10.1093/glycob/cwac061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/30/2022] [Accepted: 09/05/2022] [Indexed: 01/07/2023] Open
Abstract
Enteropathogenic Escherichia coli O125, the cause of infectious diarrheal disease, is comprised of two serogroups, viz., O125ab and O125ac, which display the aggregative adherence pattern with epithelial cells. Herein, the structure of the O-antigen polysaccharide from E. coli O125ac:H6 has been elucidated. Sugar analysis revealed the presence of fucose, mannose, galactose and N-acetyl-galactosamine as major components. Unassigned 1H and 13C NMR data from one- and two-dimensional NMR experiments of the O125ac O-antigen in conjunction with sugar components were used as input to the CASPER program, which can determine polysaccharide structure in a fully automated way, and resulted in the following branched pentasaccharide structure of the repeating unit: →4)[β-d-Galp-(1 → 3)]-β-d-GalpNAc-(1 → 2)-α-d-Manp-(1 → 3)-α-l-Fucp-(1 → 3)-α-d-GalpNAc-(1→, where the side chain is denoted by square brackets. The proposed O-antigen structure was confirmed by 1H and 13C NMR chemical shift assignments and determination of interresidue connectivities. Based on this structure, that of the O125ab O-antigen, which consists of hexasaccharide repeating units with an additional glucosyl group, was possible to establish in a semi-automated fashion by CASPER. The putative existence of gnu and gne in the gene clusters of the O125 serogroups is manifested by N-acetyl-d-galactosamine residues as the initial sugar residue of the biological repeating unit as well as within the repeating unit. The close similarity between O-antigen structures is consistent with the presence of two subgroups in the E. coli O125 serogroup.
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Affiliation(s)
- Axel Furevi
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Klas I Udekwu
- Department of Aquatic Sciences and Assessment, Swedish University of Agriculture, P.O. Box 7050, SE-750 07 Uppsala, Sweden
| | - Göran Widmalm
- To whom correspondence should be addressed: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden. e-mail:
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Abstract
The first critical step in a virus’s infection cycle is attachment to its host. This interaction is precise enough to ensure the virus will be able to productively infect the cell, but some flexibility can be beneficial to enable coevolution and host range switching or expansion. Bacteriophage Sf6 utilizes a two-step process to recognize and attach to its host Shigella flexneri. Sf6 first recognizes the lipopolysaccharide (LPS) of S. flexneri and then binds outer membrane protein (Omp) A or OmpC. This phage infects serotype Y strains but can also form small, turbid plaques on serotype 2a2; turbid plaques appear translucent rather than transparent, indicating greater survival of bacteria. Reduced plating efficiency further suggested inefficient infection. To examine the interactions between Sf6 and this alternate host, phages were experimentally evolved using mixed populations of S. flexneri serotypes Y and 2a2. The recovered mutants could infect serotype 2a2 with greater efficiency than the ancestral Sf6, forming clear plaques on both serotypes. All mutations mapped to two distinct regions of the receptor-binding tailspike protein: (i) adjacent to the LPS binding site near the N terminus; and (ii) at the distal, C-terminal tip of the protein. Although we anticipated interactions between the Sf6 tailspike and 2a2 O-antigen to be weak, LPS of this serotype appears to inhibit infection through strong binding of particles, effectively removing them from the environment. The mutations of the evolved strains reduce the inhibitory effect by either reducing electrostatic interactions with the O-antigen or increasing reliance on the Omp secondary receptors. IMPORTANCE Viruses depend on host cells to propagate themselves. In mixed populations and communities of host cells, finding these susceptible host cells may have to be balanced with avoiding nonhost cells. Alternatively, being able to infect new cell types can increase the fitness of the virus. Many bacterial viruses use a two-step process to identify their hosts, binding first to an LPS receptor and then to a host protein. For Shigella virus Sf6, the tailspike protein was previously known to bind the LPS receptor. Genetic data from this work imply the tailspike also binds to the protein receptor. By experimentally evolving Sf6, we also show that point mutations in this protein can dramatically affect the binding of one or both receptors. This may provide Sf6 flexibility in identifying host cells and the ability to rapidly alter its host range under selective pressure.
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Venturini C, Petrovic Fabijan A, Fajardo Lubian A, Barbirz S, Iredell J. Biological foundations of successful bacteriophage therapy. EMBO Mol Med 2022; 14:e12435. [PMID: 35620963 PMCID: PMC9260219 DOI: 10.15252/emmm.202012435] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 12/20/2022] Open
Abstract
Bacteriophages (phages) are selective viral predators of bacteria. Abundant and ubiquitous in nature, phages can be used to treat bacterial infections (phage therapy), including refractory infections and those resistant to antibiotics. However, despite an abundance of anecdotal evidence of efficacy, significant hurdles remain before routine implementation of phage therapy into medical practice, including a dearth of robust clinical trial data. Phage-bacterium interactions are complex and diverse, characterized by co-evolution trajectories that are significantly influenced by the environments in which they occur (mammalian body sites, water, soil, etc.). An understanding of the molecular mechanisms underpinning these dynamics is essential for successful clinical translation. This review aims to cover key aspects of bacterium-phage interactions that affect bacterial killing by describing the most relevant published literature and detailing the current knowledge gaps most likely to influence therapeutic success.
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Affiliation(s)
- Carola Venturini
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, NSW, Australia.,Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Aleksandra Petrovic Fabijan
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, NSW, Australia.,Faculty of Health and Medicine, School of Medicine, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Alicia Fajardo Lubian
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, NSW, Australia.,Faculty of Health and Medicine, School of Medicine, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Stefanie Barbirz
- Department of Medicine, Science Faculty, MSB Medical School Berlin, Berlin, Germany
| | - Jonathan Iredell
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, NSW, Australia.,Faculty of Health and Medicine, School of Medicine, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.,Westmead Hospital, Western Sydney Local Health District, Westmead, NSW, Australia
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Teh MY, Tran ENH, Morona R. Bacteriophage Sf6 host range mutant that infects Shigella flexneri serotype 2a2 strains. FEMS Microbiol Lett 2022; 369:6537400. [PMID: 35218200 PMCID: PMC8973906 DOI: 10.1093/femsle/fnac020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/24/2022] [Accepted: 02/24/2022] [Indexed: 11/13/2022] Open
Abstract
Shigella flexneri serotype 2a2 (II:9;10) is the most prevalent strain in causing bacillary dysentery in developing countries. Chemical modifications such as glucosylation, O-acetylation, and phosphoethanolamine modifications of lipopolysaccharide (LPS) O antigen (Oag) contribute to the emergence of various serotypes. Sf6 is a Shigella-specific bacteriophage that infects only a limited range of S. flexneri serotypes [X, Y]. LPS Oag is the primary receptor for bacteriophage Sf6 where it uses its tailspike protein (TSP) in binding and hydrolysing LPS Oags. Sf6TSP has recently been shown to be capable of hydrolysing the LPS Oag of Type II strains, albeit modestly. Phage therapy has regained attention in recent years as an alternative therapeutic approach. Therefore, this study aimed to expand the host range of Sf6 to the prevalent S. flexneri serotype 2a2 strain. We discovered a new lytic Sf6 host range mutant that is capable of infecting S. flexneri serotype 2a2 and identified residues in Sf6TSP that may potentially be involved in binding and hydrolysing serotype 2a2 LPS Oag. This work increased the limited Shigella-specific bacteriophage collection and may be useful in the future for phage therapy and/or biocontrolling of S. flexneri in contaminated food and water.
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Affiliation(s)
- Min Yan Teh
- School of Biological Sciences, Department of Molecular and Biomedical Science, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, 5005, Australia
| | - Elizabeth Ngoc Hoa Tran
- School of Biological Sciences, Department of Molecular and Biomedical Science, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, 5005, Australia
| | - Renato Morona
- School of Biological Sciences, Department of Molecular and Biomedical Science, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, 5005, Australia
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