1
|
Lu T, Das S, Howlader DR, Picking WD, Picking WL. Shigella Vaccines: The Continuing Unmet Challenge. Int J Mol Sci 2024; 25:4329. [PMID: 38673913 PMCID: PMC11050647 DOI: 10.3390/ijms25084329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/09/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
Shigellosis is a severe gastrointestinal disease that annually affects approximately 270 million individuals globally. It has particularly high morbidity and mortality in low-income regions; however, it is not confined to these regions and occurs in high-income nations when conditions allow. The ill effects of shigellosis are at their highest in children ages 2 to 5, with survivors often exhibiting impaired growth due to infection-induced malnutrition. The escalating threat of antibiotic resistance further amplifies shigellosis as a serious public health concern. This review explores Shigella pathology, with a primary focus on the status of Shigella vaccine candidates. These candidates include killed whole-cells, live attenuated organisms, LPS-based, and subunit vaccines. The strengths and weaknesses of each vaccination strategy are considered. The discussion includes potential Shigella immunogens, such as LPS, conserved T3SS proteins, outer membrane proteins, diverse animal models used in Shigella vaccine research, and innovative vaccine development approaches. Additionally, this review addresses ongoing challenges that necessitate action toward advancing effective Shigella prevention and control measures.
Collapse
Affiliation(s)
- Ti Lu
- Department of Veterinary Pathobiology and Bond Life Science Center, University of Missouri, Columbia, MO 65201, USA; (D.R.H.); (W.D.P.)
| | - Sayan Das
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA;
| | - Debaki R. Howlader
- Department of Veterinary Pathobiology and Bond Life Science Center, University of Missouri, Columbia, MO 65201, USA; (D.R.H.); (W.D.P.)
| | - William D. Picking
- Department of Veterinary Pathobiology and Bond Life Science Center, University of Missouri, Columbia, MO 65201, USA; (D.R.H.); (W.D.P.)
| | - Wendy L. Picking
- Department of Veterinary Pathobiology and Bond Life Science Center, University of Missouri, Columbia, MO 65201, USA; (D.R.H.); (W.D.P.)
| |
Collapse
|
2
|
Jakob S, Steinchen W, Hanßmann J, Rosum J, Langenfeld K, Osorio-Valeriano M, Steube N, Giammarinaro PI, Hochberg GKA, Glatter T, Bange G, Diepold A, Thanbichler M. The virulence regulator VirB from Shigella flexneri uses a CTP-dependent switch mechanism to activate gene expression. Nat Commun 2024; 15:318. [PMID: 38182620 PMCID: PMC10770331 DOI: 10.1038/s41467-023-44509-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 12/11/2023] [Indexed: 01/07/2024] Open
Abstract
The transcriptional antisilencer VirB acts as a master regulator of virulence gene expression in the human pathogen Shigella flexneri. It binds DNA sequences (virS) upstream of VirB-dependent promoters and counteracts their silencing by the nucleoid-organizing protein H-NS. However, its precise mode of action remains unclear. Notably, VirB is not a classical transcription factor but related to ParB-type DNA-partitioning proteins, which have recently been recognized as DNA-sliding clamps using CTP binding and hydrolysis to control their DNA entry gate. Here, we show that VirB binds CTP, embraces DNA in a clamp-like fashion upon its CTP-dependent loading at virS sites and slides laterally on DNA after clamp closure. Mutations that prevent CTP-binding block VirB loading in vitro and abolish the formation of VirB nucleoprotein complexes as well as virulence gene expression in vivo. Thus, VirB represents a CTP-dependent molecular switch that uses a loading-and-sliding mechanism to control transcription during bacterial pathogenesis.
Collapse
Affiliation(s)
- Sara Jakob
- Department of Biology, University of Marburg, Marburg, Germany
| | - Wieland Steinchen
- Department of Chemistry, University of Marburg, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Juri Hanßmann
- Department of Biology, University of Marburg, Marburg, Germany
- Max Planck Fellow Group Bacterial Cell Biology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Julia Rosum
- Department of Biology, University of Marburg, Marburg, Germany
| | - Katja Langenfeld
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Manuel Osorio-Valeriano
- Department of Biology, University of Marburg, Marburg, Germany
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Niklas Steube
- Evolutionary Biochemistry Group, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Pietro I Giammarinaro
- Department of Chemistry, University of Marburg, Marburg, Germany
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Georg K A Hochberg
- Department of Chemistry, University of Marburg, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
- Evolutionary Biochemistry Group, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Timo Glatter
- Mass Spectrometry and Proteomics Facility, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Gert Bange
- Department of Chemistry, University of Marburg, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
- Max Planck Fellow Group Molecular Physiology of Microbes, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Martin Thanbichler
- Department of Biology, University of Marburg, Marburg, Germany.
- Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany.
- Max Planck Fellow Group Bacterial Cell Biology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
| |
Collapse
|
3
|
Gabor CE, Hazen TH, Delaine-Elias BC, Rasko DA, Barry EM. Genomic, transcriptomic, and phenotypic differences among archetype Shigella flexneri strains of serotypes 2a, 3a, and 6. mSphere 2023; 8:e0040823. [PMID: 37830809 PMCID: PMC10732043 DOI: 10.1128/msphere.00408-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 08/30/2023] [Indexed: 10/14/2023] Open
Abstract
IMPORTANCE Given the genomic diversity between S. flexneri serotypes and the paucity of data to support serotype-specific phenotypic differences, we applied in silico and in vitro functional analyses of archetype strains of 2457T (Sf2a), J17B (Sf3a), and CH060 (Sf6). These archetype strains represent the three leading S. flexneri serotypes recommended for inclusion in multivalent vaccines. Characterizing the genomic and phenotypic variation among these clinically prevalent serotypes is an important step toward understanding serotype-specific host-pathogen interactions to optimize the efficacy of multivalent vaccines and therapeutics. This study underpins the importance for further large-scale serotype-targeted analyses.
Collapse
Affiliation(s)
- Caitlin E. Gabor
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Tracy H. Hazen
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - BreOnna C. Delaine-Elias
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - David A. Rasko
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Center for Pathogen Research, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Eileen M. Barry
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
4
|
Antar H, Gruber S. VirB, a transcriptional activator of virulence in Shigella flexneri, uses CTP as a cofactor. Commun Biol 2023; 6:1204. [PMID: 38007587 PMCID: PMC10676424 DOI: 10.1038/s42003-023-05590-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 11/15/2023] [Indexed: 11/27/2023] Open
Abstract
VirB is a transcriptional activator of virulence in the gram-negative bacterium Shigella flexneri encoded by the large invasion plasmid, pINV. It counteracts the transcriptional silencing by the nucleoid structuring protein, H-NS. Mutations in virB lead to loss of virulence. Studies suggested that VirB binds to specific DNA sequences, remodels the H-NS nucleoprotein complexes, and changes DNA supercoiling. VirB belongs to the superfamily of ParB proteins which are involved in plasmid and chromosome partitioning often as part of a ParABS system. Like ParB, VirB forms discrete foci in Shigella flexneri cells harbouring pINV. Our results reveal that purified preparations of VirB specifically bind the ribonucleotide CTP and slowly but detectably hydrolyse it with mild stimulation by the virS targeting sequences found on pINV. We show that formation of VirB foci in cells requires a virS site and CTP binding residues in VirB. Curiously, DNA stimulation of clamp closure appears efficient even without a virS sequence in vitro. Specificity for entrapment of virS DNA is however evident at elevated salt concentrations. These findings suggest that VirB acts as a CTP-dependent DNA clamp and indicate that the cellular microenvironment contributes to the accumulation of VirB specifically at virS sites.
Collapse
Affiliation(s)
- Hammam Antar
- Department of Fundamental Microbiology (DMF), Faculty of Biology and Medicine (FBM), University of Lausanne, 1015, Lausanne, Switzerland
| | - Stephan Gruber
- Department of Fundamental Microbiology (DMF), Faculty of Biology and Medicine (FBM), University of Lausanne, 1015, Lausanne, Switzerland.
| |
Collapse
|
5
|
Gerson TM, Ott AM, Karney MMA, Socea JN, Ginete DR, Iyer LM, Aravind L, Gary RK, Wing HJ. VirB, a key transcriptional regulator of Shigella virulence, requires a CTP ligand for its regulatory activities. mBio 2023; 14:e0151923. [PMID: 37728345 PMCID: PMC10653881 DOI: 10.1128/mbio.01519-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 07/25/2023] [Indexed: 09/21/2023] Open
Abstract
IMPORTANCE Shigella species cause bacillary dysentery, the second leading cause of diarrheal deaths worldwide. There is a pressing need to identify novel molecular drug targets. Shigella virulence phenotypes are controlled by the transcriptional regulator, VirB. We show that VirB belongs to a fast-evolving, plasmid-borne clade of the ParB superfamily, which has diverged from versions with a distinct cellular role-DNA partitioning. We report that, like classic members of the ParB family, VirB binds a highly unusual ligand, CTP. Mutants predicted to be defective in CTP binding are compromised in a variety of virulence attributes controlled by VirB, likely because these mutants cannot engage DNA. This study (i) reveals that VirB binds CTP, (ii) provides a link between VirB-CTP interactions and Shigella virulence phenotypes, (iii) provides new insight into VirB-CTP-DNA interactions, and (iv) broadens our understanding of the ParB superfamily, a group of bacterial proteins that play critical roles in many bacteria.
Collapse
Affiliation(s)
- Taylor M. Gerson
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, USA
| | - Audrey M. Ott
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, USA
| | - Monika M. A. Karney
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, USA
| | - Jillian N. Socea
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, USA
| | - Daren R. Ginete
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, USA
| | | | - L. Aravind
- Computational Biology Branch, National Library of Medicine, Bethesda, Maryland, USA
| | - Ronald K. Gary
- Department of Chemistry and Biochemistry, University of Nevada Las Vegas, Las Vegas, Nevada, USA
| | - Helen J. Wing
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, USA
| |
Collapse
|
6
|
Miljkovic M, Lozano S, Castellote I, de Cózar C, Villegas-Moreno AI, Gamallo P, Jimenez-Alfaro Martinez D, Fernández-Álvaro E, Ballell L, Garcia GA. Novel inhibitors that target bacterial virulence identified via HTS against intra-macrophage survival of Shigella flexneri. mSphere 2023; 8:e0015423. [PMID: 37565760 PMCID: PMC10597453 DOI: 10.1128/msphere.00154-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/02/2023] [Indexed: 08/12/2023] Open
Abstract
Shigella flexneri is a facultative intracellular pathogen that causes shigellosis, a human diarrheal disease characterized by the destruction of the colonic epithelium. Novel antimicrobial compounds to treat infections are urgently needed due to the proliferation of bacterial antibiotic resistance and lack of new effective antimicrobials in the market. Our approach to find compounds that block the Shigella virulence pathway has three potential advantages: (i) resistance development should be minimized due to the lack of growth selection pressure, (ii) no resistance due to environmental antibiotic exposure should be developed since the virulence pathways are not activated outside of host infection, and (iii) the normal intestinal microbiota, which do not have the targeted virulence pathways, should be unharmed. We chose to utilize two phenotypic assays, inhibition of Shigella survival in macrophages and Shigella growth inhibition (minimum inhibitory concentration), to interrogate the 1.7 M compound screening collection subset of the GlaxoSmithKline drug discovery chemical library. A number of secondary assays on the hit compounds resulting from the primary screens were conducted, which, in combination with chemical, structural, and physical property analyses, narrowed the final hit list to 44 promising compounds for further drug discovery efforts. The rapid development of antibiotic resistance is a critical problem that has the potential of returning the world to a "pre-antibiotic" type of environment, where millions of people will die from previously treatable infections. One relatively newer approach to minimize the selection pressures for the development of resistance is to target virulence pathways. This is anticipated to eliminate any resistance selection pressure in environmental exposure to virulence-targeted antibiotics and will have the added benefit of not affecting the non-virulent microbiome. This paper describes the development and application of a simple, reproducible, and sensitive assay to interrogate an extensive chemical library in high-throughput screening format for activity against the survival of Shigella flexneri 2457T-nl in THP-1 macrophages. The ability to screen very large numbers of compounds in a reasonable time frame (~1.7 M compounds in ~8 months) distinguishes this assay as a powerful tool in further exploring new compounds with intracellular effect on S. flexneri or other pathogens with similar pathways of pathogenesis. The assay utilizes a luciferase reporter which is extremely rapid, simple, relatively inexpensive, and sensitive and possesses a broad linear range. The assay also utilized THP-1 cells that resemble primary monocytes and macrophages in morphology and differentiation properties. THP-1 cells have advantages over human primary monocytes or macrophages because they are highly plastic and their homogeneous genetic background minimizes the degree of variability in the cell phenotype (1). The intracellular and virulence-targeted selectivity of our methodology, determined via secondary screening, is an enormous advantage. Our main interest focuses on hits that are targeting virulence, and the most promising compounds with adequate physicochemical and drug metabolism and pharmacokinetic (DMPK) properties will be progressed to a suitable in vivo shigellosis model to evaluate the therapeutic potential of this approach. Additionally, compounds that act via a host-directed mechanism could be a promising source for further research given that it would allow a whole new, specific, and controlled approach to the treatment of diseases caused by some pathogenic bacteria.
Collapse
Affiliation(s)
- Marija Miljkovic
- Department of Medical Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
- GSK Global Health Unit, Madrid, Spain
| | | | | | | | | | | | | | | | | | - George A. Garcia
- Department of Medical Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| |
Collapse
|
7
|
Huang C, Pham HQ, Zhu L, Wang R, Law OK, Lin SL, Nie QC, Zhang L, Wang X, Lau TCK. Comparative Analysis of Transcriptome and Proteome Revealed the Common Metabolic Pathways Induced by Prevalent ESBL Plasmids in Escherichia coli. Int J Mol Sci 2023; 24:14009. [PMID: 37762311 PMCID: PMC10531281 DOI: 10.3390/ijms241814009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/11/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Antibiotic resistance has emerged as one of the most significant threats to global public health. Plasmids, which are highly efficient self-replicating genetic vehicles, play a critical role in the dissemination of drug-resistant genes. Previous studies have mainly focused on drug-resistant genes only, often neglecting the complete functional role of multidrug-resistant (MDR) plasmids in bacteria. In this study, we conducted a comprehensive investigation of the transcriptomes and proteomes of Escherichia coli J53 transconjugants harboring six major MDR plasmids of different incompatibility (Inc) groups, which were clinically isolated from patients. The RNA-seq analysis revealed that MDR plasmids influenced the gene expression in the bacterial host, in particular, the genes related to metabolic pathways. A proteomic analysis demonstrated the plasmid-induced regulation of several metabolic pathways including anaerobic respiration and the utilization of various carbon sources such as serine, threonine, sialic acid, and galactarate. These findings suggested that MDR plasmids confer a growth advantage to bacterial hosts in the gut, leading to the expansion of plasmid-carrying bacteria over competitors without plasmids. Moreover, this study provided insights into the versatility of prevalent MDR plasmids in moderating the cellular gene network of bacteria, which could potentially be utilized in therapeutics development for bacteria carrying MDR plasmids.
Collapse
Affiliation(s)
- Chuan Huang
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong SAR, China; (C.H.); (H.-Q.P.); (L.Z.); (R.W.); (O.-K.L.); (S.-L.L.); (Q.-C.N.); (L.Z.)
- Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong SAR, China
| | - Hoa-Quynh Pham
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong SAR, China; (C.H.); (H.-Q.P.); (L.Z.); (R.W.); (O.-K.L.); (S.-L.L.); (Q.-C.N.); (L.Z.)
- Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong SAR, China
| | - Lina Zhu
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong SAR, China; (C.H.); (H.-Q.P.); (L.Z.); (R.W.); (O.-K.L.); (S.-L.L.); (Q.-C.N.); (L.Z.)
- Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong SAR, China
| | - Rui Wang
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong SAR, China; (C.H.); (H.-Q.P.); (L.Z.); (R.W.); (O.-K.L.); (S.-L.L.); (Q.-C.N.); (L.Z.)
- Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong SAR, China
| | - Oi-Kwan Law
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong SAR, China; (C.H.); (H.-Q.P.); (L.Z.); (R.W.); (O.-K.L.); (S.-L.L.); (Q.-C.N.); (L.Z.)
- Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong SAR, China
| | - Shu-Ling Lin
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong SAR, China; (C.H.); (H.-Q.P.); (L.Z.); (R.W.); (O.-K.L.); (S.-L.L.); (Q.-C.N.); (L.Z.)
- Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong SAR, China
| | - Qi-Chang Nie
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong SAR, China; (C.H.); (H.-Q.P.); (L.Z.); (R.W.); (O.-K.L.); (S.-L.L.); (Q.-C.N.); (L.Z.)
- Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong SAR, China
| | - Liang Zhang
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong SAR, China; (C.H.); (H.-Q.P.); (L.Z.); (R.W.); (O.-K.L.); (S.-L.L.); (Q.-C.N.); (L.Z.)
- Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong SAR, China
| | - Xin Wang
- Department of Surgery, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China;
| | - Terrence Chi-Kong Lau
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong SAR, China; (C.H.); (H.-Q.P.); (L.Z.); (R.W.); (O.-K.L.); (S.-L.L.); (Q.-C.N.); (L.Z.)
- Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong SAR, China
| |
Collapse
|
8
|
Haidar-Ahmad N, Manigat FO, Silué N, Pontier SM, Campbell-Valois FX. A Tale about Shigella: Evolution, Plasmid, and Virulence. Microorganisms 2023; 11:1709. [PMID: 37512882 PMCID: PMC10383432 DOI: 10.3390/microorganisms11071709] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
Shigella spp. cause hundreds of millions of intestinal infections each year. They target the mucosa of the human colon and are an important model of intracellular bacterial pathogenesis. Shigella is a pathovar of Escherichia coli that is characterized by the presence of a large invasion plasmid, pINV, which encodes the characteristic type III secretion system and icsA used for cytosol invasion and cell-to-cell spread, respectively. First, we review recent advances in the genetic aspects of Shigella, shedding light on its evolutionary history within the E. coli lineage and its relationship to the acquisition of pINV. We then discuss recent insights into the processes that allow for the maintenance of pINV. Finally, we describe the role of the transcription activators VirF, VirB, and MxiE in the major virulence gene regulatory cascades that control the expression of the type III secretion system and icsA. This provides an opportunity to examine the interplay between these pINV-encoded transcriptional activators and numerous chromosome-encoded factors that modulate their activity. Finally, we discuss novel chromosomal genes icaR, icaT, and yccE that are regulated by MxiE. This review emphasizes the notion that Shigella and E. coli have walked the fine line between commensalism and pathogenesis for much of their history.
Collapse
Affiliation(s)
- Nathaline Haidar-Ahmad
- Host-Microbe Interactions Laboratory, Centre for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - France Ourida Manigat
- Host-Microbe Interactions Laboratory, Centre for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Navoun Silué
- Host-Microbe Interactions Laboratory, Centre for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Stéphanie M Pontier
- Centre de Recherche Santé Environnementale et Biodiversité de l'Outaouais (SEBO), CEGEP de l'Outaouais, Gatineau, QC J8Y 6M4, Canada
| | - François-Xavier Campbell-Valois
- Host-Microbe Interactions Laboratory, Centre for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Centre for Infection, Immunity and Inflammation, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| |
Collapse
|
9
|
Gerson TM, Ott AM, Karney MMA, Socea JN, Ginete DR, Iyer LM, Aravind L, Gary RK, Wing HJ. VirB, a key transcriptional regulator of Shigella virulence, requires a CTP ligand for its regulatory activities. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.16.541010. [PMID: 37293012 PMCID: PMC10245682 DOI: 10.1101/2023.05.16.541010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The VirB protein, encoded by the large virulence plasmid of Shigella spp., is a key transcriptional regulator of virulence genes. Without a functional virB gene, Shigella cells are avirulent. On the virulence plasmid, VirB functions to offset transcriptional silencing mediated by the nucleoid structuring protein, H-NS, which binds and sequesters AT-rich DNA, making it inaccessible for gene expression. Thus, gaining a mechanistic understanding of how VirB counters H-NS-mediated silencing is of considerable interest. VirB is unusual in that it does not resemble classic transcription factors. Instead, its closest relatives are found in the ParB superfamily, where the best-characterized members function in faithful DNA segregation before cell division. Here, we show that VirB is a fast-evolving member of this superfamily and report for the first time that the VirB protein binds a highly unusual ligand, CTP. VirB binds this nucleoside triphosphate preferentially and with specificity. Based on alignments with the best-characterized members of the ParB family, we identify amino acids of VirB likely to bind CTP. Substitutions in these residues disrupt several well-documented activities of VirB, including its anti-silencing activity at a VirB-dependent promoter, its role in generating a Congo red positive phenotype in Shigella , and the ability of the VirB protein to form foci in the bacterial cytoplasm when fused to GFP. Thus, this work is the first to show that VirB is a bona fide CTP-binding protein and links Shigella virulence phenotypes to the nucleoside triphosphate, CTP. Importance Shigella species cause bacillary dysentery (shigellosis), the second leading cause of diarrheal deaths worldwide. With growing antibiotic resistance, there is a pressing need to identify novel molecular drug targets. Shigella virulence phenotypes are controlled by the transcriptional regulator, VirB. We show that VirB belongs to a fast-evolving, primarily plasmid-borne clade of the ParB superfamily, which has diverged from versions that have a distinct cellular role - DNA partitioning. We are the first to report that, like classic members of the ParB family, VirB binds a highly unusual ligand, CTP. Mutants predicted to be defective in CTP binding are compromised in a variety of virulence attributes controlled by VirB. This study i) reveals that VirB binds CTP, ii) provides a link between VirB-CTP interactions and Shigella virulence phenotypes, and iii) broadens our understanding of the ParB superfamily, a group of bacterial proteins that play critical roles in many different bacteria.
Collapse
Affiliation(s)
- Taylor M. Gerson
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Audrey M. Ott
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Monika MA. Karney
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Jillian N. Socea
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Daren R. Ginete
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Lakshminarayan M. Iyer
- Computational Biology Branch, 8600 Rockville Pike, Building 38A, Room 5N505, National Library of Medicine, Bethesda, MD 20894
| | - L. Aravind
- Computational Biology Branch, 8600 Rockville Pike, Building 38A, Room 5N505, National Library of Medicine, Bethesda, MD 20894
| | - Ronald K. Gary
- Department of Chemistry and Biochemistry, University of Nevada Las Vegas, Las Vegas, NV 89154-4003
| | - Helen J. Wing
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| |
Collapse
|
10
|
Picker MA, Karney MMA, Gerson TM, Karabachev A, Duhart J, McKenna J, Wing H. Localized modulation of DNA supercoiling, triggered by the Shigella anti-silencer VirB, is sufficient to relieve H-NS-mediated silencing. Nucleic Acids Res 2023; 51:3679-3695. [PMID: 36794722 PMCID: PMC10164555 DOI: 10.1093/nar/gkad088] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 02/17/2023] Open
Abstract
In Bacteria, nucleoid structuring proteins govern nucleoid dynamics and regulate transcription. In Shigella spp., at ≤30°C, the histone-like nucleoid structuring protein (H-NS) transcriptionally silences many genes on the large virulence plasmid. Upon a switch to 37°C, VirB, a DNA binding protein and key transcriptional regulator of Shigella virulence, is produced. VirB functions to counter H-NS-mediated silencing in a process called transcriptional anti-silencing. Here, we show that VirB mediates a loss of negative DNA supercoils from our plasmid-borne, VirB-regulated PicsP-lacZ reporter in vivo. The changes are not caused by a VirB-dependent increase in transcription, nor do they require the presence of H-NS. Instead, the VirB-dependent change in DNA supercoiling requires the interaction of VirB with its DNA binding site, a critical first step in VirB-dependent gene regulation. Using two complementary approaches, we show that VirB:DNA interactions in vitro introduce positive supercoils in plasmid DNA. Subsequently, by exploiting transcription-coupled DNA supercoiling, we reveal that a localized loss of negative supercoils is sufficient to alleviate H-NS-mediated transcriptional silencing independently of VirB. Together, our findings provide novel insight into VirB, a central regulator of Shigella virulence and, more broadly, a molecular mechanism that offsets H-NS-dependent silencing of transcription in bacteria.
Collapse
Affiliation(s)
- Michael A Picker
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Monika M A Karney
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Taylor M Gerson
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | | | - Juan C Duhart
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Joy A McKenna
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| | - Helen J Wing
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154-4004, USA
| |
Collapse
|
11
|
Lynch JP, González-Prieto C, Reeves AZ, Bae S, Powale U, Godbole NP, Tremblay JM, Schmidt FI, Ploegh HL, Kansra V, Glickman JN, Leong JM, Shoemaker CB, Garrett WS, Lesser CF. Engineered Escherichia coli for the in situ secretion of therapeutic nanobodies in the gut. Cell Host Microbe 2023; 31:634-649.e8. [PMID: 37003258 PMCID: PMC10101937 DOI: 10.1016/j.chom.2023.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 12/20/2022] [Accepted: 03/08/2023] [Indexed: 04/03/2023]
Abstract
Drug platforms that enable the directed delivery of therapeutics to sites of diseases to maximize efficacy and limit off-target effects are needed. Here, we report the development of PROT3EcT, a suite of commensal Escherichia coli engineered to secrete proteins directly into their surroundings. These bacteria consist of three modular components: a modified bacterial protein secretion system, the associated regulatable transcriptional activator, and a secreted therapeutic payload. PROT3EcT secrete functional single-domain antibodies, nanobodies (Nbs), and stably colonize and maintain an active secretion system within the intestines of mice. Furthermore, a single prophylactic dose of a variant of PROT3EcT that secretes a tumor necrosis factor-alpha (TNF-α)-neutralizing Nb is sufficient to ablate pro-inflammatory TNF levels and prevent the development of injury and inflammation in a chemically induced model of colitis. This work lays the foundation for developing PROT3EcT as a platform for the treatment of gastrointestinal-based diseases.
Collapse
Affiliation(s)
- Jason P Lynch
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02115, USA; Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Coral González-Prieto
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02115, USA; Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Analise Z Reeves
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02115, USA; Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Sena Bae
- Departments of Immunology and Infectious Diseases and Harvard T.H. Chan Center for the Microbiome in Public Health, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Urmila Powale
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02115, USA; Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Neha P Godbole
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02115, USA; Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Jacqueline M Tremblay
- Department of Infectious Disease and Global Health, Tufts Cummings School of Veterinary Medicine, North Grafton, MA 01536, USA
| | - Florian I Schmidt
- Institute of Innate Immunity, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Hidde L Ploegh
- Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | | | - Jonathan N Glickman
- Department of Pathology, Massachusetts General Hospital, Boston, MA 02115, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA; Tufts Stuart B Levy Center for Integrated Management of Antimicrobial Resistance, Tufts University, Boston, MA 02111, USA
| | - Charles B Shoemaker
- Department of Infectious Disease and Global Health, Tufts Cummings School of Veterinary Medicine, North Grafton, MA 01536, USA; Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Wendy S Garrett
- Departments of Immunology and Infectious Diseases and Harvard T.H. Chan Center for the Microbiome in Public Health, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Cammie F Lesser
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02115, USA; Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Ragon Institute of Harvard and MIT, Cambridge, MA 02139, USA.
| |
Collapse
|
12
|
Flacht L, Lunelli M, Kaszuba K, Chen ZA, Reilly FJO, Rappsilber J, Kosinski J, Kolbe M. Integrative structural analysis of the type III secretion system needle complex from Shigella flexneri. Protein Sci 2023; 32:e4595. [PMID: 36790757 PMCID: PMC10019453 DOI: 10.1002/pro.4595] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 01/31/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023]
Abstract
The type III secretion system (T3SS) is a large, transmembrane protein machinery used by various pathogenic gram-negative bacteria to transport virulence factors into the host cell during infection. Understanding the structure of T3SSs is crucial for future developments of therapeutics that could target this system. However, much of the knowledge about the structure of T3SS is available only for Salmonella, and it is unclear how this large assembly is conserved across species. Here, we combined cryo-electron microscopy, cross-linking mass spectrometry, and integrative modeling to determine the structure of the T3SS needle complex from Shigella flexneri. We show that the Shigella T3SS exhibits unique features distinguishing it from other structurally characterized T3SSs. The secretin pore complex adopts a new fold of its C-terminal S domain and the pilotin MxiM[SctG] locates around the outer surface of the pore. The export apparatus structure exhibits a conserved pseudohelical arrangement but includes the N-terminal domain of the SpaS[SctU] subunit, which was not present in any of the previously published virulence-related T3SS structures. Similar to other T3SSs, however, the apparatus is anchored within the needle complex by a network of flexible linkers that either adjust conformation to connect to equivalent patches on the secretin oligomer or bind distinct surface patches at the same height of the export apparatus. The conserved and unique features delineated by our analysis highlight the necessity to analyze T3SS in a species-specific manner, in order to fully understand the underlying molecular mechanisms of these systems. The structure of the type III secretion system from Shigella flexneri delineates conserved and unique features, which could be used for the development of broad-range therapeutics.
Collapse
Affiliation(s)
- Lara Flacht
- Department for Structural Infection BiologyCenter for Structural Systems Biology (CSSB) & Helmholtz Centre for Infection Research (HZI)HamburgGermany
- Dynamics of Viral Structures, Leibniz Institute for Virology (LIV)HamburgGermany
| | - Michele Lunelli
- Department for Structural Infection BiologyCenter for Structural Systems Biology (CSSB) & Helmholtz Centre for Infection Research (HZI)HamburgGermany
| | - Karol Kaszuba
- Department for Structural Infection BiologyCenter for Structural Systems Biology (CSSB) & Helmholtz Centre for Infection Research (HZI)HamburgGermany
- Centre for Structural Systems Biology (CSSB) & European Molecular Biology Laboratory (EMBL)HamburgGermany
| | - Zhuo Angel Chen
- Technische Universität Berlin, Institute of Biotechnology, Chair of BioanalyticsBerlinGermany
| | - Francis J. O'. Reilly
- Technische Universität Berlin, Institute of Biotechnology, Chair of BioanalyticsBerlinGermany
| | - Juri Rappsilber
- Technische Universität Berlin, Institute of Biotechnology, Chair of BioanalyticsBerlinGermany
- University of Edinburgh, Wellcome Centre for Cell BiologyEdinburghUK
| | - Jan Kosinski
- Centre for Structural Systems Biology (CSSB) & European Molecular Biology Laboratory (EMBL)HamburgGermany
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
| | - Michael Kolbe
- Department for Structural Infection BiologyCenter for Structural Systems Biology (CSSB) & Helmholtz Centre for Infection Research (HZI)HamburgGermany
- MIN‐FacultyUniversity HamburgHamburgGermany
| |
Collapse
|
13
|
Picker MA, Karney MMA, Gerson TM, Karabachev AD, Duhart JC, McKenna JA, Wing HJ. Localized modulation of DNA supercoiling, triggered by the Shigella anti-silencer VirB, is sufficient to relieve H-NS-mediated silencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523335. [PMID: 36711906 PMCID: PMC9882051 DOI: 10.1101/2023.01.09.523335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In Bacteria, nucleoid structuring proteins govern nucleoid dynamics and regulate transcription. In Shigella spp ., at ≤ 30 °C, the histone-like nucleoid structuring protein (H-NS) transcriptionally silences many genes on the large virulence plasmid. Upon a switch to 37 °C, VirB, a DNA binding protein and key transcriptional regulator of Shigella virulence, is produced. VirB functions to counter H-NS-mediated silencing in a process called transcriptional anti-silencing. Here, we show that VirB mediates a loss of negative DNA supercoils from our plasmid-borne, VirB-regulated PicsP-lacZ reporter, in vivo . The changes are not caused by a VirB-dependent increase in transcription, nor do they require the presence of H-NS. Instead, the VirB-dependent change in DNA supercoiling requires the interaction of VirB with its DNA binding site, a critical first step in VirB-dependent gene regulation. Using two complementary approaches, we show that VirB:DNA interactions in vitro introduce positive supercoils in plasmid DNA. Subsequently, by exploiting transcription-coupled DNA supercoiling, we reveal that a localized loss of negative supercoils is sufficient to alleviate H-NS-mediated transcriptional silencing, independently of VirB. Together, our findings provide novel insight into VirB, a central regulator of Shigella virulence and more broadly, a molecular mechanism that offsets H-NS-dependent silencing of transcription in bacteria.
Collapse
|
14
|
Hall CP, Jadeja NB, Sebeck N, Agaisse H. Characterization of MxiE- and H-NS-Dependent Expression of ipaH7.8, ospC1, yccE, and yfdF in Shigella flexneri. mSphere 2022; 7:e0048522. [PMID: 36346241 PMCID: PMC9769918 DOI: 10.1128/msphere.00485-22] [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: 09/29/2022] [Accepted: 10/10/2022] [Indexed: 11/09/2022] Open
Abstract
Shigella flexneri uses a type 3 secretion system (T3SS) apparatus to inject virulence effector proteins into the host cell cytosol. Upon host cell contact, MxiE, an S. flexneri AraC-like transcriptional regulator, is required for the expression of a subset of T3SS effector genes encoded on the large virulence plasmid. Here, we defined the MxiE regulon using RNA-seq. We identified virulence plasmid- and chromosome-encoded genes that are activated in response to type 3 secretion in a MxiE-dependent manner. Bioinformatic analysis revealed that similar to previously known MxiE-dependent genes, chromosome-encoded genes yccE and yfdF contain a regulatory element known as the MxiE box, which is required for their MxiE-dependent expression. The significant AT enrichment of MxiE-dependent genes suggested the involvement of H-NS. Using a dominant negative H-NS system, we demonstrate that H-NS silences the expression of MxiE-dependent genes located on the virulence plasmid (ipaH7.8 and ospC1) and the chromosome (yccE and yfdF). Furthermore, we show that MxiE is no longer required for the expression of ipaH7.8, ospC1, yccE, and yfdF when H-NS silencing is relieved. Finally, we show that the H-NS anti-silencer VirB is not required for ipaH7.8 and yccE expression upon MxiE/IpgC overexpression. Based on these genetic studies, we propose a model of MxiE-dependent gene regulation in which MxiE counteracts H-NS-mediated silencing. IMPORTANCE The expression of horizontally acquired genes, including virulence genes, is subject to complex regulation involving xenogeneic silencing proteins, and counter-silencing mechanisms. The pathogenic properties of Shigella flexneri mainly rely on the acquisition of the type 3 secretion system (T3SS) and cognate effector proteins, whose expression is repressed by the xenogeneic silencing protein H-NS. Based on previous studies, releasing H-NS-mediated silencing mainly relies on two mechanisms involving (i) a temperature shift leading to the release of H-NS at the virF promoter, and (ii) the virulence factor VirB, which dislodges H-NS upon binding to specific motifs upstream of virulence genes, including those encoding the T3SS. In this study, we provide genetic evidence supporting the notion that, in addition to VirB, the AraC family member MxiE also contributes to releasing H-NS-mediated silencing in S. flexneri.
Collapse
Affiliation(s)
- Chelsea P. Hall
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Niti B. Jadeja
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Natalie Sebeck
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| |
Collapse
|
15
|
Geurtsen J, de Been M, Weerdenburg E, Zomer A, McNally A, Poolman J. Genomics and pathotypes of the many faces of Escherichia coli. FEMS Microbiol Rev 2022; 46:6617594. [PMID: 35749579 PMCID: PMC9629502 DOI: 10.1093/femsre/fuac031] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 06/22/2022] [Indexed: 01/09/2023] Open
Abstract
Escherichia coli is the most researched microbial organism in the world. Its varied impact on human health, consisting of commensalism, gastrointestinal disease, or extraintestinal pathologies, has generated a separation of the species into at least eleven pathotypes (also known as pathovars). These are broadly split into two groups, intestinal pathogenic E. coli (InPEC) and extraintestinal pathogenic E. coli (ExPEC). However, components of E. coli's infinite open accessory genome are horizontally transferred with substantial frequency, creating pathogenic hybrid strains that defy a clear pathotype designation. Here, we take a birds-eye view of the E. coli species, characterizing it from historical, clinical, and genetic perspectives. We examine the wide spectrum of human disease caused by E. coli, the genome content of the bacterium, and its propensity to acquire, exchange, and maintain antibiotic resistance genes and virulence traits. Our portrayal of the species also discusses elements that have shaped its overall population structure and summarizes the current state of vaccine development targeted at the most frequent E. coli pathovars. In our conclusions, we advocate streamlining efforts for clinical reporting of ExPEC, and emphasize the pathogenic potential that exists throughout the entire species.
Collapse
Affiliation(s)
- Jeroen Geurtsen
- Janssen Vaccines and Prevention B.V., 2333 Leiden, the Netherlands
| | - Mark de Been
- Janssen Vaccines and Prevention B.V., 2333 Leiden, the Netherlands
| | | | - Aldert Zomer
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 Utrecht, the Netherlands
| | - Alan McNally
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, B15 2TT Birmingham, United Kingdom
| | - Jan Poolman
- Janssen Vaccines and Prevention B.V., 2333 Leiden, the Netherlands
| |
Collapse
|
16
|
Roles of Two-Component Signal Transduction Systems in Shigella Virulence. Biomolecules 2022; 12:biom12091321. [PMID: 36139160 PMCID: PMC9496106 DOI: 10.3390/biom12091321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
Two-component signal transduction systems (TCSs) are widespread types of protein machinery, typically consisting of a histidine kinase membrane sensor and a cytoplasmic transcriptional regulator that can sense and respond to environmental signals. TCSs are responsible for modulating genes involved in a multitude of bacterial functions, including cell division, motility, differentiation, biofilm formation, antibiotic resistance, and virulence. Pathogenic bacteria exploit the capabilities of TCSs to reprogram gene expression according to the different niches they encounter during host infection. This review focuses on the role of TCSs in regulating the virulence phenotype of Shigella, an intracellular pathogen responsible for severe human enteric syndrome. The pathogenicity of Shigella is the result of the complex action of a wide number of virulence determinants located on the chromosome and on a large virulence plasmid. In particular, we will discuss how five TCSs, EnvZ/OmpR, CpxA/CpxR, ArcB/ArcA, PhoQ/PhoP, and EvgS/EvgA, contribute to linking environmental stimuli to the expression of genes related to virulence and fitness within the host. Considering the relevance of TCSs in the expression of virulence in pathogenic bacteria, the identification of drugs that inhibit TCS function may represent a promising approach to combat bacterial infections.
Collapse
|
17
|
Liang J, Zhu Z, Lan R, Meng J, Vrancken B, Lu S, Jin D, Yang J, Wang J, Qin T, Pu J, Zhang L, Dong K, Xu M, Tian H, Jiang T, Xu J. Evolutionary and genomic insights into the long-term colonization of Shigella flexneri in animals. Emerg Microbes Infect 2022; 11:2069-2079. [PMID: 35930371 PMCID: PMC9448383 DOI: 10.1080/22221751.2022.2109514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The enteroinvasive bacterium Shigella flexneri is known as a highly host-adapted human pathogen. There had been no known other reservoirs reported until recently. Here 34 isolates obtained from animals (yaks, dairy cows and beef cattle) from 2016-2017 and 268 human S. flexneri isolates from China were sequenced to determine the relationships between animal and human isolates and infer the evolutionary history of animal-associated S. flexneri. The 18 animal isolates (15 yak and 3 beef cattle isolates) in PG1 were separated into 4 lineages, and the 16 animal isolates (1 yak, 5 beef cattle and 10 dairy cow isolates) in PG3 were clustered in 8 lineages. The most recent human isolates from China belonged to PG3 whereas Chinese isolates from the 1950s-1960s belonged to PG1. PG1 S. flexneri may has been transmitted to the yaks during PG1 circulation in the human population in China and has remained in the yak population since, while PG3 S. flexneri in animals were likely recent transmissions from the human population. Increased stability of the large virulence plasmid and acquisition of abundant antimicrobial resistance determinants may have enabled PG3 to expand globally and replaced PG1 in China. Our study confirms that animals may act as a reservoir for S. flexneri. Genomic analysis revealed the evolutionary history of multiple S. flexneri lineages in animals and humans in China. However, further studies are required to determine the public health threat of S. flexneri from animals.
Collapse
Affiliation(s)
- Junrong Liang
- State Key laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Zhen Zhu
- College of Life Science and Food Engineering, Hebei University of Engineering, Handan, China
| | - Ruiting Lan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Jing Meng
- Institute of Systems Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Suzhou Institute of Systems Medicine, Suzhou, China
| | - Bram Vrancken
- Department of Microbiology and Immunology, Rega Institute, Laboratory of Evolutionary and Computational Virology, KU Leuven, Leuven, Belgium
| | - Shan Lu
- State Key laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.,Research Units of Discovery of Unknown Bacteria and Function, Chinese Academy of Medical Sciences, Beijing, China
| | - Dong Jin
- State Key laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.,Research Units of Discovery of Unknown Bacteria and Function, Chinese Academy of Medical Sciences, Beijing, China
| | - Jing Yang
- State Key laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.,Research Units of Discovery of Unknown Bacteria and Function, Chinese Academy of Medical Sciences, Beijing, China
| | - Jianping Wang
- State Key laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Tian Qin
- State Key laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Ji Pu
- State Key laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Li Zhang
- Institute of Systems Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Suzhou Institute of Systems Medicine, Suzhou, China
| | - Kui Dong
- Shanxi Eye Hospital, Taiyuan, China
| | - Mingchao Xu
- State Key laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Huaiyu Tian
- State Key Laboratory of Remote Sensing Science, Center for Global Change and Public Health, College of Global Change and Earth System Science, Beijing Normal University, Beijing, China
| | - Taijiao Jiang
- Institute of Systems Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Suzhou Institute of Systems Medicine, Suzhou, China.,Guangzhou Laboratory, Guangzhou, China
| | - Jianguo Xu
- State Key laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Research Units of Discovery of Unknown Bacteria and Function, Chinese Academy of Medical Sciences, Beijing, China.,Research Institute of Public Heath, Nankai University, Tianjin, China
| |
Collapse
|
18
|
Bullones-Bolaños A, Bernal-Bayard J, Ramos-Morales F. The NEL Family of Bacterial E3 Ubiquitin Ligases. Int J Mol Sci 2022; 23:7725. [PMID: 35887072 PMCID: PMC9320238 DOI: 10.3390/ijms23147725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 12/16/2022] Open
Abstract
Some pathogenic or symbiotic Gram-negative bacteria can manipulate the ubiquitination system of the eukaryotic host cell using a variety of strategies. Members of the genera Salmonella, Shigella, Sinorhizobium, and Ralstonia, among others, express E3 ubiquitin ligases that belong to the NEL family. These bacteria use type III secretion systems to translocate these proteins into host cells, where they will find their targets. In this review, we first introduce type III secretion systems and the ubiquitination process and consider the various ways bacteria use to alter the ubiquitin ligation machinery. We then focus on the members of the NEL family, their expression, translocation, and subcellular localization in the host cell, and we review what is known about the structure of these proteins, their function in virulence or symbiosis, and their specific targets.
Collapse
Affiliation(s)
| | | | - Francisco Ramos-Morales
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain; (A.B.-B.); (J.B.-B.)
| |
Collapse
|
19
|
Torrez Lamberti MF, Terán LC, Lopez FE, de Las Mercedes Pescaretti M, Delgado MA. Genomic and proteomic characterization of two strains of Shigella flexneri 2 isolated from infants' stool samples in Argentina. BMC Genomics 2022; 23:495. [PMID: 35804311 PMCID: PMC9264714 DOI: 10.1186/s12864-022-08711-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/15/2022] [Indexed: 11/24/2022] Open
Abstract
Background Shigella specie is a globally important intestinal pathogen disseminated all over the world. In this study we analyzed the genome and the proteomic component of two Shigella flexneri 2a clinical isolates, collected from pediatric patients with gastroenteritis of the Northwest region of Argentina (NWA) in two periods of time, with four years of difference. Our goal was to determine putative changes at molecular levels occurred during these four years, that could explain the presence of this Shigella`s serovar as the prevalent pathogen in the population under study. Results As previously reported, our findings support the idea of Shigella has a conserved “core” genome, since comparative studies of CI133 and CI172 genomes performed against 80 genomes obtained from the NCBI database, showed that there is a large number of genes shared among all of them. However, we observed that CI133 and CI172 harbors a small number of strain-specific genes, several of them present in mobile genetic elements, supporting the hypothesis that these isolates were established in the population by horizontal acquisition of genes. These differences were also observed at proteomic level, where it was possible to detect the presence of certain secreted proteins in a culture medium that simulates the host environment. Conclusion Great similarities were observed between the CI133 and CI172 strains, confirming the high percentage of genes constituting the “core” genome of S. flexneri 2. However, numerous strain specific genes were also determined. The presence of the here identified molecular elements into other strain of our culture collation, is currently used to develop characteristic markers of local pathogens. In addition, the most outstanding result of this study was the first description of a S. flexneri 2 producing Colicin E, as one of the characteristics that allows S. flexneri 2 to persist in the microbial community. These findings could also contribute to clarify the mechanism and the evolution strategy used by this pathogen to specifically colonize, survive, and cause infection within the NWA population. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08711-5.
Collapse
Affiliation(s)
- Mónica F Torrez Lamberti
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, 5Q7R+96, San Miguel de Tucumán, Argentina
| | - Lucrecia C Terán
- Centro de Referencia Para Lactobacilos (CERELA-CONICET), Chacabuco 145, 5Q9R+3J, San Miguel de Tucumán, Argentina
| | - Fabián E Lopez
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, 5Q7R+96, San Miguel de Tucumán, Argentina.,Universidad Nacional de Chilecito (UNdeC), 9 de Julio 22, F5360CKB, Chilecito, La Rioja, Argentina
| | - María de Las Mercedes Pescaretti
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, 5Q7R+96, San Miguel de Tucumán, Argentina.
| | - Mónica A Delgado
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, 5Q7R+96, San Miguel de Tucumán, Argentina.
| |
Collapse
|
20
|
Abstract
Pyroptosis, a regulated form of pro-inflammatory cell death, is characterised by cell lysis and by the release of cytokines, damage- and pathogen-associated molecular patterns. It plays an important role during bacterial infection, where it can promote an inflammatory response and eliminate the replicative niche of intracellular pathogens. Recent work, using a variety of bacterial pathogens, has illuminated the versatility of pyroptosis, revealing unexpected and important concepts underlying host defence. In this Review, we overview the molecular mechanisms underlying pyroptosis and discuss their role in host defence, from the single cell to the whole organism. We focus on recent studies using three cellular microbiology paradigms - Mycobacterium tuberculosis, Salmonella Typhimurium and Shigella flexneri - that have transformed the field of pyroptosis. We compare insights discovered in tissue culture, zebrafish and mouse models, highlighting the advantages and disadvantages of using these complementary infection models to investigate pyroptosis and for modelling human infection. Moving forward, we propose that in-depth knowledge of pyroptosis obtained from complementary infection models can better inform future studies using higher vertebrates, including humans, and help develop innovative host-directed therapies to combat bacterial infection.
Collapse
Affiliation(s)
- Dominik Brokatzky
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Serge Mostowy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| |
Collapse
|
21
|
The AraC/XylS Protein MxiE and Its Coregulator IpgC Control a Negative Feedback Loop in the Transcriptional Cascade That Regulates Type III Secretion in Shigella flexneri. J Bacteriol 2022; 204:e0013722. [PMID: 35703565 DOI: 10.1128/jb.00137-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the AraC family of transcriptional regulators (AFTRs) control the expression of many genes important to cellular processes, including virulence. In Shigella species, the type III secretion system (T3SS), a key determinant for host cell invasion, is regulated by the three-tiered VirF/VirB/MxiE transcriptional cascade. Both VirF and MxiE belong to the AFTRs and are characterized as positive transcriptional regulators. Here, we identify a novel regulatory activity for MxiE and its coregulator IpgC, which manifests as a negative feedback loop in the VirF/VirB/MxiE transcriptional cascade. Our findings show that MxiE and IpgC downregulate the virB promoter and, hence, VirB protein production, thus decreasing VirB-dependent promoter activity at ospD1, one of the nearly 50 VirB-dependent genes. At the virB promoter, regions required for negative MxiE- and IpgC-dependent regulation were mapped and found to be coincident with regions required for positive VirF-dependent regulation. In tandem, negative MxiE- and IpgC-dependent regulation of the virB promoter only occurred in the presence of VirF, suggesting that MxiE and IpgC can function to counter VirF activation of the virB promoter. Lastly, MxiE and IpgC do not downregulate another VirF-activated promoter, icsA, demonstrating that this negative feedback loop targets the virB promoter. Our study provides insight into a mechanism that may reprogram Shigella virulence gene expression following type III secretion and provides the impetus to examine if MxiE and IpgC homologs in other important bacterial pathogens, such as Burkholderia pseudomallei and Salmonella enterica serovars Typhimurium and Typhi, coordinate similar negative feedback loops. IMPORTANCE The large AraC family of transcriptional regulators (AFTRs) control virulence gene expression in many bacterial pathogens. In Shigella species, the AraC/XylS protein MxiE and its coregulator IpgC positively regulate the expression of type III secretion system genes within the three-tiered VirF/VirB/MxiE transcriptional cascade. Our findings suggest a negative feedback loop in the VirF/VirB/MxiE cascade, in which MxiE and IpgC counter VirF-dependent activation of the virB promoter, thus making this the first characterization of negative MxiE- and IpgC-dependent regulation. Our study provides insight into a mechanism that likely reprograms Shigella virulence gene expression following type III secretion, which has implications for other important bacterial pathogens with functional homologs of MxiE and IpgC.
Collapse
|
22
|
Pilla G, Arcari G, Tang CM, Carattoli A. Virulence plasmid pINV as a genetic signature for Shigella flexneri phylogeny. Microb Genom 2022; 8. [PMID: 35759406 PMCID: PMC9455713 DOI: 10.1099/mgen.0.000846] [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] [Indexed: 11/18/2022] Open
Abstract
Shigella flexneri is a major health burden in low- and middle-income countries, where it is a leading cause of mortality associated with diarrhoea in children, and shows an increasing incidence among travellers and men having sex with men. Like all Shigella spp., S. flexneri has evolved from commensal Escherichia coli following the acquisition of a large plasmid pINV, which contains genes essential for virulence. Current sequence typing schemes of Shigella are based on combinations of chromosomal genetic loci, since pINV-encoded virulence genes are often lost during growth in the laboratory, making these elements inappropriate for sequence typing. By performing comparative analysis of pINVs from S. flexneri strains isolated from different geographical regions and belonging to different serotypes, we found that in contrast to plasmid-encoded virulence genes, plasmid maintenance genes are highly stable pINV-encoded elements. For the first time, to our knowledge, we have developed a S. flexneri plasmid multilocus sequence typing (pMLST) method based on different combinations of alleles of the vapBC and yacAB toxin–antitoxin (TA) systems, and the parAB partitioning system. This enables typing of S. flexneri pINV plasmids into distinct ‘virulence sequence types’ (vSTs). Furthermore, the phylogenies of vST alleles and bacterial host core genomes suggests an intimate co-evolution of pINV with the chromosome of its bacterial host, consistent with previous findings. This work demonstrates the potential of plasmid maintenance loci as genetic characteristics to study as well as to trace the molecular phylogenesis of S. flexneri pINV and the phylogenetic relationship of this plasmid with its bacterial host.
Collapse
Affiliation(s)
- Giulia Pilla
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Gabriele Arcari
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | |
Collapse
|
23
|
icaR
and
icaT
Are Ancient Chromosome Genes Encoding Substrates of the Type III Secretion Apparatus in Shigella flexneri. mSphere 2022; 7:e0011522. [PMID: 35582904 PMCID: PMC9241512 DOI: 10.1128/msphere.00115-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shigella is an Escherichia coli pathovar that colonizes the cytosol of mucosal cells in the human large intestine. To do this, Shigella uses a Type III Secretion Apparatus (T3SA) to translocate several proteins into host cells. The T3SA and its substrates are encoded by genes of the virulence plasmid pINV or by chromosomal genes derived thereof. We recently discovered two chromosomal genes, which seem unrelated to pINV, although they are activated by MxiE and IpgC similarly to some of the canonical substrates of the T3SA. Here, we showed that the production of the corresponding proteins depended on the conservation of a MxiE box in their cognate promoters. Furthermore, both proteins were secreted by the T3SA in a chaperone-independent manner through the recognition of their respective amino-terminal secretion signal. Based on these observations, we named these new genes icaR and icaT, which stand for invasion chromosome antigen with homology for a transcriptional regulator and a transposase, respectively. icaR and icaT have orthologs in commensal and pathogenic E. coli strains belonging mainly to phylogroups A, B1, D and E. Finally, we demonstrated that icaR and icaT orthologs could be activated by the coproduction of IpgC and MxiE in strains MG1655 K-12 (phylogroup A) and O157:H7 ATCC 43888 (phylogroup E). In contrast, the coproduction of EivF and YgeG, which are homologs of MxiE and IpgC in the E. coli T3SS 2 (ETT2), failed to activate icaR and icaT. IMPORTANCEicaR and icaT are the latest members of the MxiE regulon discovered in the chromosome. The proteins IcaR and IcaT, albeit produced in small amounts, are nonetheless secreted by the T3SA comparably to canonical substrates. The high occurrence of icaR and icaT in phylogroups A, B1, D, and E coupled with their widespread absence in their B2 counterparts agree with the consensus E. coli phylogeny. The widespread conservation of the MxiE box among icaR and icaT orthologs supports the notion that both genes had already undergone coevolution with transcriptional activators ipgC and mxiE- harbored in pINV or a relative- in the last common ancestor of Shigella and of E. coli from phylogroups A, B1, D, and E. The possibility that icaR and icaT may contribute to Shigella pathogenesis cannot be excluded, although some of their characteristics suggest they are fossil genes.
Collapse
|
24
|
A Highly Unstable and Elusive Plasmid That Encodes the Type III Secretion System Is Necessary for Full Virulence in the Marine Fish Pathogen Photobacterium damselae subsp. piscicida. Int J Mol Sci 2022; 23:ijms23094729. [PMID: 35563122 PMCID: PMC9105992 DOI: 10.3390/ijms23094729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 01/27/2023] Open
Abstract
The marine bacterium Photobacterium damselae subsp. piscicida (Pdp) causes photobacteriosis in fish and important financial losses in aquaculture, but knowledge of its virulence factors is still scarce. We here demonstrate that an unstable plasmid (pPHDPT3) that encodes a type III secretion system (T3SS) is highly prevalent in Pdp strains from different geographical origins and fish host species. We found that pPHDPT3 undergoes curing upon in vitro cultivation, and this instability constitutes a generalized feature of pPHDPT3-like plasmids in Pdp strains. pPHDPT3 markers were detected in tissues of naturally-infected moribund fish and in the Pdp colonies grown directly from the fish tissues but were undetectable in a fraction of the colonies produced upon the first passage of the primeval colonies on agar plates. Notably, cured strains exhibited a marked reduction in virulence for fish, demonstrating that pPHDPT3 is a major virulence factor of Pdp. The attempts to stabilize pPHDPT3 by insertion of antibiotic resistance markers by allelic exchange caused an even greater reduction in virulence. We hypothesize that the existence of a high pressure to shed pPHDPT3 plasmid in vitro caused the selection of clones with off-target mutations and gene rearrangements during the process of genetic modification. Collectively, these results show that pPHDPT3 constitutes a novel, hitherto unreported virulence factor of Pdp that shows a high instability in vitro and warn that the picture of Pdp virulence genes has been historically underestimated, since the loss of the T3SS and other plasmid-borne genes may have occurred systematically in laboratories for decades.
Collapse
|
25
|
Maintenance of the Shigella sonnei virulence plasmid is dependent on its repertoire and amino acid sequence of toxin:antitoxin systems. J Bacteriol 2022; 204:e0051921. [PMID: 34978459 PMCID: PMC8923223 DOI: 10.1128/jb.00519-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shigella sonnei is a major cause of bacillary dysentery and an increasing concern due to the spread of multidrug resistance. S. sonnei harbors pINV, an ∼210 kb plasmid that encodes a type III secretion system (T3SS), which is essential for virulence. During growth in the laboratory, avirulence arises spontaneously in S. sonnei at high frequency, hampering studies on and vaccine development against this important pathogen. Here, we investigated the molecular basis for the emergence of avirulence in S. sonnei and showed that avirulence mainly results from pINV loss, which is consistent with previous findings. Ancestral deletions have led to the loss from S. sonnei pINV of two toxin-antitoxin (TA) systems involved in plasmid maintenance, CcdAB and GmvAT, which are found on pINV in Shigella flexneri. We showed that the introduction of these TA systems into S. sonnei pINV reduced but did not eliminate pINV loss, while the single amino acid polymorphisms found in the S. sonnei VapBC TA system compared with S. flexneri VapBC also contributed to pINV loss. Avirulence also resulted from deletions of T3SS-associated genes in pINV through recombination between insertion sequences (ISs) on the plasmid. These events differed from those observed in S. flexneri due to the different distribution and repertoire of ISs. Our findings demonstrated that TA systems and ISs influenced plasmid dynamics and loss in S. sonnei and could be exploited for the design and evaluation of vaccines. IMPORTANCEShigella sonnei is the major cause of shigellosis in high-income and industrializing countries and is an emerging, multidrug-resistant pathogen. A significant challenge when studying this bacterium is that it spontaneously becomes avirulent during growth in the laboratory through loss of its virulence plasmid (pINV). Here, we deciphered the mechanisms leading to avirulence in S. sonnei and how the limited repertoire and amino acid sequences of plasmid-encoded toxin-antitoxin (TA) systems make the maintenance of pINV in this bacterium less efficient compared with Shigella flexneri. Our findings highlighted how subtle differences in plasmids in closely related species have marked effects and could be exploited to reduce plasmid loss in S. sonnei. This should facilitate research on this bacterium and vaccine development.
Collapse
|
26
|
Zhang X, Payne M, Nguyen T, Kaur S, Lan R. Cluster-specific gene markers enhance Shigella and enteroinvasive Escherichia coli in silico serotyping. Microb Genom 2021; 7. [PMID: 34889728 PMCID: PMC8767346 DOI: 10.1099/mgen.0.000704] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Shigella and enteroinvasive Escherichia coli (EIEC) cause human bacillary dysentery with similar invasion mechanisms and share similar physiological, biochemical and genetic characteristics. Differentiation of Shigella from EIEC is important for clinical diagnostic and epidemiological investigations. However, phylogenetically, Shigella and EIEC strains are composed of multiple clusters and are different forms of E. coli, making it difficult to find genetic markers to discriminate between Shigella and EIEC. In this study, we identified 10 Shigella clusters, seven EIEC clusters and 53 sporadic types of EIEC by examining over 17000 publicly available Shigella and EIEC genomes. We compared Shigella and EIEC accessory genomes to identify cluster-specific gene markers for the 17 clusters and 53 sporadic types. The cluster-specific gene markers showed 99.64% accuracy and more than 97.02% specificity. In addition, we developed a freely available in silico serotyping pipeline named Shigella EIEC Cluster Enhanced Serotype Finder (ShigEiFinder) by incorporating the cluster-specific gene markers and established Shigella and EIEC serotype-specific O antigen genes and modification genes into typing. ShigEiFinder can process either paired-end Illumina sequencing reads or assembled genomes and almost perfectly differentiated Shigella from EIEC with 99.70 and 99.74% cluster assignment accuracy for the assembled genomes and read mapping respectively. ShigEiFinder was able to serotype over 59 Shigella serotypes and 22 EIEC serotypes and provided a high specificity of 99.40% for assembled genomes and 99.38% for read mapping for serotyping. The cluster-specific gene markers and our new serotyping tool, ShigEiFinder (installable package: https://github.com/LanLab/ShigEiFinder, online tool: https://mgtdb.unsw.edu.au/ShigEiFinder/), will be useful for epidemiological and diagnostic investigations.
Collapse
Affiliation(s)
- Xiaomei Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Michael Payne
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Thanh Nguyen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Sandeep Kaur
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Ruiting Lan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| |
Collapse
|
27
|
Locke RK, Greig DR, Jenkins C, Dallman TJ, Cowley LA. Acquisition and loss of CTX-M plasmids in Shigella species associated with MSM transmission in the UK. Microb Genom 2021; 7. [PMID: 34427554 PMCID: PMC8549364 DOI: 10.1099/mgen.0.000644] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Shigellosis in men who have sex with men (MSM) is caused by multidrug resistant Shigellae, exhibiting resistance to antimicrobials including azithromycin, ciprofloxacin and more recently the third-generation cephalosporins. We sequenced four blaCTX-M-27-positive MSM Shigella isolates (2018–20) using Oxford Nanopore Technologies; three S. sonnei (identified as two MSM clade 2, one MSM clade 5) and one S. flexneri 3a, to explore AMR context. All S. sonnei isolates harboured Tn7/Int2 chromosomal integrons, whereas S. flexneri 3a contained the Shigella Resistance Locus. All strains harboured IncFII pKSR100-like plasmids (67-83kbp); where present blaCTX-M-27 was located on these plasmids flanked by IS26 and IS903B, however blaCTX-M-27 was lost in S. flexneri 3a during storage between Illumina and Nanopore sequencing. IncFII AMR regions were mosaic and likely reorganised by IS26; three of the four plasmids contained azithromycin-resistance genes erm(B) and mph(A) and one harboured the pKSR100 integron. Additionally, all S. sonnei isolates possessed a large IncB/O/K/Z plasmid, two of which carried aph(3’)-Ib/aph(6)-Id/sul2 and tet(A). Monitoring the transmission of mobile genetic elements with co-located AMR determinants is necessary to inform empirical treatment guidance and clinical management of MSM-associated shigellosis.
Collapse
Affiliation(s)
| | - David R Greig
- Gastrointestinal Reference Services, Public Health England, London, UK.,Division of Infection and Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, EH25 9RG, UK
| | - Claire Jenkins
- Gastrointestinal Reference Services, Public Health England, London, UK
| | - Tim J Dallman
- Gastrointestinal Reference Services, Public Health England, London, UK.,Division of Infection and Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, EH25 9RG, UK
| | | |
Collapse
|
28
|
VirB, a key transcriptional regulator of virulence plasmid genes in Shigella flexneri, forms DNA-binding site dependent foci in the bacterial cytoplasm. J Bacteriol 2021; 203:JB.00627-20. [PMID: 33722845 PMCID: PMC8117518 DOI: 10.1128/jb.00627-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
VirB is a key regulator of genes located on the large virulence plasmid (pINV) in the bacterial pathogen Shigella flexneri VirB is unusual; it is not related to other transcriptional regulators, instead, it belongs to a family of proteins that primarily function in plasmid and chromosome partitioning; exemplified by ParB. Despite this, VirB does not function to segregate DNA, but rather counters transcriptional silencing mediated by the nucleoid structuring protein, H-NS. Since ParB localizes subcellularly as discrete foci in the bacterial cytoplasm, we chose to investigate the subcellular localization of VirB to gain novel insight into how VirB functions as a transcriptional anti-silencer. To do this, a GFP-VirB fusion that retains the regulatory activity of VirB and yet, does not undergo significant protein degradation in S. flexneri, was used. Surprisingly, discrete fluorescent foci were observed in live wild-type S. flexneri cells and an isogenic virB mutant using fluorescence microscopy. In contrast, foci were rarely observed (<10%) in pINV-cured cells or in cells expressing a GFP-VirB fusion carrying amino acid substitutions in the VirB DNA binding domain. Finally, the 25 bp VirB-binding site was demonstrated to be sufficient and necessary for GFP-VirB focus formation using a set of small surrogate plasmids. Combined, these data demonstrate that the VirB:DNA interactions required for the transcriptional anti-silencing activity of VirB on pINV are a prerequisite for the subcellular localization of VirB in the bacterial cytoplasm. The significance of these findings, in light of the anti-silencing activity of VirB, is discussed.ImportanceThis study reveals the subcellular localization of VirB, a key transcriptional regulator of virulence genes found on the large virulence plasmid (pINV) in Shigella. Fluorescent signals generated by an active GFP-VirB fusion form 2, 3, or 4 discrete foci in the bacterial cytoplasm, predominantly at the quarter cell position. These signals are completely dependent upon VirB interacting with its DNA binding site found either on the virulence plasmid or an engineered surrogate. Our findings: 1) provide novel insight into VirB:pINV interactions, 2) suggest that VirB may have utility as a DNA marker, and 3) raise questions about how and why this anti-silencing protein that controls virulence gene expression on pINV of Shigella spp. forms discrete foci/hubs within the bacterial cytoplasm.
Collapse
|
29
|
Seferbekova Z, Zabelkin A, Yakovleva Y, Afasizhev R, Dranenko NO, Alexeev N, Gelfand MS, Bochkareva OO. High Rates of Genome Rearrangements and Pathogenicity of Shigella spp. Front Microbiol 2021; 12:628622. [PMID: 33912145 PMCID: PMC8072062 DOI: 10.3389/fmicb.2021.628622] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 03/22/2021] [Indexed: 02/01/2023] Open
Abstract
Shigella are pathogens originating within the Escherichia lineage but frequently classified as a separate genus. Shigella genomes contain numerous insertion sequences (ISs) that lead to pseudogenisation of affected genes and an increase of non-homologous recombination. Here, we study 414 genomes of E. coli and Shigella strains to assess the contribution of genomic rearrangements to Shigella evolution. We found that Shigella experienced exceptionally high rates of intragenomic rearrangements and had a decreased rate of homologous recombination compared to pathogenic and non-pathogenic E. coli. The high rearrangement rate resulted in independent disruption of syntenic regions and parallel rearrangements in different Shigella lineages. Specifically, we identified two types of chromosomally encoded E3 ubiquitin-protein ligases acquired independently by all Shigella strains that also showed a high level of sequence conservation in the promoter and further in the 5′-intergenic region. In the only available enteroinvasive E. coli (EIEC) strain, which is a pathogenic E. coli with a phenotype intermediate between Shigella and non-pathogenic E. coli, we found a rate of genome rearrangements comparable to those in other E. coli and no functional copies of the two Shigella-specific E3 ubiquitin ligases. These data indicate that the accumulation of ISs influenced many aspects of genome evolution and played an important role in the evolution of intracellular pathogens. Our research demonstrates the power of comparative genomics-based on synteny block composition and an important role of non-coding regions in the evolution of genomic islands.
Collapse
Affiliation(s)
- Zaira Seferbekova
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia.,Institute for Information Transmission Problems (The Kharkevich Institute, RAS), Moscow, Russia
| | - Alexey Zabelkin
- Computer Technologies Laboratory, ITMO University, Saint Petersburg, Russia.,JetBrains Research, Saint Petersburg, Russia.,Bioinformatics Institute, Saint Petersburg, Russia
| | - Yulia Yakovleva
- Bioinformatics Institute, Saint Petersburg, Russia.,Department of Cytology and Histology, Saint Petersburg State University, Saint Petersburg, Russia
| | - Robert Afasizhev
- Institute for Information Transmission Problems (The Kharkevich Institute, RAS), Moscow, Russia
| | - Natalia O Dranenko
- Institute for Information Transmission Problems (The Kharkevich Institute, RAS), Moscow, Russia
| | - Nikita Alexeev
- Computer Technologies Laboratory, ITMO University, Saint Petersburg, Russia
| | - Mikhail S Gelfand
- Institute for Information Transmission Problems (The Kharkevich Institute, RAS), Moscow, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Olga O Bochkareva
- Institute for Information Transmission Problems (The Kharkevich Institute, RAS), Moscow, Russia.,Institute of Science and Technology (IST Austria), Klosterneuburg, Austria
| |
Collapse
|
30
|
Bajunaid W, Haidar-Ahmad N, Kottarampatel AH, Ourida Manigat F, Silué N, F. Tchagang C, Tomaro K, Campbell-Valois FX. The T3SS of Shigella: Expression, Structure, Function, and Role in Vacuole Escape. Microorganisms 2020; 8:microorganisms8121933. [PMID: 33291504 PMCID: PMC7762205 DOI: 10.3390/microorganisms8121933] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 12/18/2022] Open
Abstract
Shigella spp. are one of the leading causes of infectious diarrheal diseases. They are Escherichia coli pathovars that are characterized by the harboring of a large plasmid that encodes most virulence genes, including a type III secretion system (T3SS). The archetypal element of the T3SS is the injectisome, a syringe-like nanomachine composed of approximately 20 proteins, spanning both bacterial membranes and the cell wall, and topped with a needle. Upon contact of the tip of the needle with the plasma membrane, the injectisome secretes its protein substrates into host cells. Some of these substrates act as translocators or effectors whose functions are key to the invasion of the cytosol and the cell-to-cell spread characterizing the lifestyle of Shigella spp. Here, we review the structure, assembly, function, and methods to measure the activity of the injectisome with a focus on Shigella, but complemented with data from other T3SS if required. We also present the regulatory cascade that controls the expression of T3SS genes in Shigella. Finally, we describe the function of translocators and effectors during cell-to-cell spread, particularly during escape from the vacuole, a key element of Shigella’s pathogenesis that has yet to reveal all of its secrets.
Collapse
Affiliation(s)
- Waad Bajunaid
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Nathaline Haidar-Ahmad
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Anwer Hasil Kottarampatel
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - France Ourida Manigat
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Navoun Silué
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Caetanie F. Tchagang
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Kyle Tomaro
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - François-Xavier Campbell-Valois
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (W.B.); (N.H.-A.); (A.H.K.); (F.O.M.); (N.S.); (C.F.T.); (K.T.)
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Correspondence:
| |
Collapse
|
31
|
Riley LW. Distinguishing Pathovars from Nonpathovars: Escherichia coli. Microbiol Spectr 2020; 8:10.1128/microbiolspec.ame-0014-2020. [PMID: 33385193 PMCID: PMC10773148 DOI: 10.1128/microbiolspec.ame-0014-2020] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Indexed: 02/07/2023] Open
Abstract
Escherichia coli is one of the most well-adapted and pathogenically versatile bacterial organisms. It causes a variety of human infections, including gastrointestinal illnesses and extraintestinal infections. It is also part of the intestinal commensal flora of humans and other mammals. Groups of E. coli that cause diarrhea are often described as intestinal pathogenic E. coli (IPEC), while those that cause infections outside of the gut are called extraintestinal pathogenic E. coli (ExPEC). IPEC can cause a variety of diarrheal illnesses as well as extraintestinal syndromes such as hemolytic-uremic syndrome. ExPEC cause urinary tract infections, bloodstream infection, sepsis, and neonatal meningitis. IPEC and ExPEC have thus come to be referred to as pathogenic variants of E. coli or pathovars. While IPEC can be distinguished from commensal E. coli based on their characteristic virulence factors responsible for their associated clinical manifestations, ExPEC cannot be so easily distinguished. IPEC most likely have reservoirs outside of the human intestine but it is unclear if ExPEC represent nothing more than commensal E. coli that breach a sterile barrier to cause extraintestinal infections. This question has become more complicated by the advent of whole genome sequencing (WGS) that has raised a new question about the taxonomic characterization of E. coli based on traditional clinical microbiologic and phylogenetic methods. This review discusses how molecular epidemiologic approaches have been used to address these questions, and how answers to these questions may contribute to our better understanding of the epidemiology of infections caused by E. coli. *This article is part of a curated collection.
Collapse
Affiliation(s)
- Lee W Riley
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, CA 94720
| |
Collapse
|
32
|
Mei L, Qiu X, Jiang C, Yang A. Host Delipidation Mediated by Bacterial Effectors. Trends Microbiol 2020; 29:238-250. [PMID: 33092951 DOI: 10.1016/j.tim.2020.09.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 12/19/2022]
Abstract
Protein lipidation, the covalent attachment of a lipid moiety to a target protein, plays a critical role in many cellular processes in eukaryotic cells. Bacterial pathogens secrete various effectors to subvert the host signaling pathway as a mechanism of microbial pathogenesis. An increasing number of effectors from diverse bacterial pathogens function as cysteine proteases to cause irreversible delipidation of host lipidated proteins. This in turn results in disruption of crucial lipidation-mediated host signal transduction, thereby enabling pathogen survival and replication. In this review, we discuss the role of the bacterial effectors in interactions with the host and highlight our knowledge of irreversible host delipidation, with a focus on the common concerted biochemical mechanisms of the bacterial effectors.
Collapse
Affiliation(s)
- Ligang Mei
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Xiaofeng Qiu
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Chen Jiang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Aimin Yang
- School of Life Sciences, Chongqing University, Chongqing 401331, China; Ultrafast Transient Materials Science Center, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing 401331, China.
| |
Collapse
|
33
|
Bacterial virulence mediated by orthogonal post-translational modification. Nat Chem Biol 2020; 16:1043-1051. [PMID: 32943788 DOI: 10.1038/s41589-020-0638-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/30/2020] [Indexed: 12/28/2022]
Abstract
Many bacterial pathogens secrete virulence factors, also known as effector proteins, directly into host cells. These effectors suppress pro-inflammatory host signaling while promoting bacterial infection. A particularly interesting subset of effectors post-translationally modify host proteins using novel chemistry that is not otherwise found in the mammalian proteome, which we refer to as 'orthogonal post-translational modification' (oPTM). In this Review, we profile oPTM chemistry for effectors that catalyze serine/threonine acetylation, phosphate β-elimination, phosphoribosyl-linked ubiquitination, glutamine deamidation, phosphocholination, cysteine methylation, arginine N-acetylglucosaminylation, and glutamine ADP-ribosylation on host proteins. AMPylation, a PTM that could be considered orthogonal until only recently, is also discussed. We further highlight known cellular targets of oPTMs and their resulting biological consequences. Developing a complete understanding of oPTMs and the host cell processes they hijack will illuminate critical steps in the infection process, which can be harnessed for a variety of therapeutic, diagnostic, and synthetic applications.
Collapse
|
34
|
Inactivation of the sfgtr4 Gene of Shigella flexneri Induces Biofilm Formation and Affects Bacterial Pathogenicity. Microorganisms 2020; 8:microorganisms8060841. [PMID: 32512756 PMCID: PMC7355660 DOI: 10.3390/microorganisms8060841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/08/2020] [Accepted: 05/21/2020] [Indexed: 01/08/2023] Open
Abstract
Biofilm formation is a significant cause for the environmental persistence of foodborne pathogens. This phenomenon remains misunderstood in Shigellaflexneri whose pathogenicity is mainly associated with the virulence plasmid pWR100. Sequence analysis of the latter predicts a putative lipopolysaccharides (LPS) glycosyltransferase (Gtr) encoded by Sfgtr4, which is the second gene of the SfpgdA-orf186-virK-msbB2 locus. We demonstrated here that purified SfGtr4 exhibited a Gtr activity in vitro by transferring glucose to lipid A. To establish the role of SfGtr4 in virulence, we generated a Sfgtr4 mutant and assessed its phenotype in vitro. Sfgtr4 mutant significantly reduced HeLa cells invasion without impairing type III effectors secretion, increased susceptibility to lysozyme degradation, and enhanced bacterial killing by polymorphonuclear neutrophils (PMNs). SfGtr4 is related to proteins required in biofilm formation. We established conditions whereby wild-type Shigella formed biofilm and revealed that its appearance was accelerated by the Sfgtr4 mutant. Additional phenotypical analysis revealed that single SfpdgA and double SfpgdA-Sfgtr4 mutants behaved similarly to Sfgtr4 mutant. Furthermore, a molecular interaction between SfGtr4 and SfPgdA was identified. In summary, the dual contribution of SfGtr4 and SfPgdA to the pathogenicity and the regulation biofilm formation by S. flexneri was demonstrated here.
Collapse
|
35
|
Michelacci V, Tozzoli R, Arancia S, D'Angelo A, Boni A, Knijn A, Prosseda G, Greig DR, Jenkins C, Camou T, Sirok A, Navarro A, Schelotto F, Varela G, Morabito S. Tracing Back the Evolutionary Route of Enteroinvasive Escherichia coli (EIEC) and Shigella Through the Example of the Highly Pathogenic O96:H19 EIEC Clone. Front Cell Infect Microbiol 2020; 10:260. [PMID: 32582565 PMCID: PMC7283534 DOI: 10.3389/fcimb.2020.00260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 05/04/2020] [Indexed: 11/13/2022] Open
Abstract
Enteroinvasive Escherichia coli (EIEC) cause intestinal illness through the same pathogenic mechanism used by Shigella spp. The latter species can be typed through genomic and phenotypic methods used for E. coli and have been proposed for reclassification within E. coli species. Recently the first appearance of a highly pathogenic EIEC O96:H19 was described in Europe as the causative agent of two large outbreaks that occurred in Italy and in the United Kingdom. In contrast to Shigella spp and to the majority of EIEC strains, EIEC O96:H19 fermented lactose, lacked pathoadaptive mutations, and showed good fitness in extracellular environment, similarly to non-pathogenic E. coli, suggesting they have emerged following acquisition of the invasion plasmid by a non-pathogenic E. coli. Here we describe the whole genome comparison of two EIEC O96:H19 strains isolated from severe cases of diarrhea in Uruguay in 2014 with the sequences of EIEC O96:H19 available in the public domain. The phylogenetic comparison grouped all the O96:H19 strains in a single cluster, while reference EIEC strains branched into different clades with Shigella strains occupying apical positions. The comparison of the virulence plasmids showed the presence of a complete conjugation region in at least one O96:H19 EIEC. Reverse Transcriptase Real Time PCR experiments confirmed in this strain the expression of the pilin-encoding gene and conjugation experiments suggested its ability to mobilize an accessory plasmid in a recipient strain. Noteworthy, the tra region was comprised between two reversely oriented IS600 elements, which were also found as remnants in another EIEC O96:H19 plasmid lacking the tra locus. We hypothesize that an IS-mediated recombination mechanism may have caused the loss of the conjugation region commonly observed in EIEC and Shigella virulence plasmids. The results of this study support the hypothesis of EIEC originating from non-pathogenic E. coli through the acquisition of the virulence plasmid via conjugation. Remarkably, this study showed the ability of a circulating EIEC strain to mobilize plasmids through conjugation, suggesting a mechanism for the emergence of novel EIEC clones.
Collapse
Affiliation(s)
- Valeria Michelacci
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Rosangela Tozzoli
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Silvia Arancia
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Alfio D'Angelo
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Arianna Boni
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Arnold Knijn
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Gianni Prosseda
- Department of Biology and Biotechnology "Charles Darwin", Università Sapienza di Roma, Rome, Italy
| | - David R Greig
- Gastrointestinal Bacteria Reference Unit (GBRU), Public Health England, E. coli, Shigella, Yersinia and Vibrio Reference Service, National Infection Service, London, United Kingdom
| | - Claire Jenkins
- Gastrointestinal Bacteria Reference Unit (GBRU), Public Health England, E. coli, Shigella, Yersinia and Vibrio Reference Service, National Infection Service, London, United Kingdom
| | - Teresa Camou
- Departamento de Laboratorios, Ministerio de Salud Pública, Montevideo, Uruguay
| | - Alfredo Sirok
- Departamento de Laboratorios, Ministerio de Salud Pública, Montevideo, Uruguay
| | - Armando Navarro
- Public Health Department, Medicine Faculty, Universidad Nacional Autónoma de Mexico (UNAM), Mexico City, Mexico
| | - Felipe Schelotto
- Departamento de Bacteriología y Virología, Facultad de Medicina, Instituto de Higiene, Universidad de la República, Montevideo, Uruguay
| | - Gustavo Varela
- Departamento de Bacteriología y Virología, Facultad de Medicina, Instituto de Higiene, Universidad de la República, Montevideo, Uruguay
| | - Stefano Morabito
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| |
Collapse
|
36
|
Nigro G, Arena ET, Sachse M, Moya-Nilges M, Marteyn BS, Sansonetti PJ, Campbell-Valois FX. Mapping of Shigella flexneri's tissue distribution and type III secretion apparatus activity during infection of the large intestine of guinea pigs. Pathog Dis 2020; 77:5580288. [PMID: 31578543 PMCID: PMC6920510 DOI: 10.1093/femspd/ftz054] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/30/2019] [Indexed: 12/12/2022] Open
Abstract
Shigella spp. are bacterial pathogens that invade the human colonic mucosa using a type III secretion apparatus (T3SA), a proteinaceous device activated upon contact with host cells. Active T3SAs translocate proteins that carve the intracellular niche of Shigella spp. Nevertheless, the activation state of the T3SA has not been addressed in vivo. Here, we used a green fluorescent protein transcription-based secretion activity reporter (TSAR) to provide a spatio-temporal description of S. flexneri T3SAs activity in the colon of Guinea pigs. First, we observed that early mucus release is triggered in the vicinity of luminal bacteria with inactive T3SA. Subsequent mucosal invasion showed bacteria with active T3SA associated with the brush border, eventually penetrating into epithelial cells. From 2 to 8 h post-challenge, the infection foci expanded, and these intracellular bacteria displayed homogeneously high-secreting activity, while extracellular foci within the lamina propria featured bacteria with low secretion activity. We also found evidence that within lamina propria macrophages, bacteria reside in vacuoles instead of accessing the cytosol. Finally, bacteria were cleared from tissues between 8 and 24 h post-challenge, highlighting the hit-and-run colonization strategy of Shigella. This study demonstrates how genetically encoded reporters can contribute to deciphering pathogenesis in vivo.
Collapse
Affiliation(s)
- Giulia Nigro
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, INSERM U1202, 24-28 rue du Docteur-Roux, 75015 Paris, France
| | - Ellen T Arena
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, INSERM U1202, 24-28 rue du Docteur-Roux, 75015 Paris, France.,Laboratory for Optical and Computational Instrumentation, University of Wisconsin-Madison, Laboratory for Optical and Computational Instrumentation, 271 Animal Sciences, 1675 Observatory Drive, Madison, WI 53706, USA
| | - Martin Sachse
- Ultrastructural Bioimaging unit, Institut Pasteur, 24-28 rue du Docteur-Roux, 75015 Paris, France
| | - Maryse Moya-Nilges
- Ultrastructural Bioimaging unit, Institut Pasteur, 24-28 rue du Docteur-Roux, 75015 Paris, France
| | - Benoit S Marteyn
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, INSERM U1202, 24-28 rue du Docteur-Roux, 75015 Paris, France.,Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS UPR9002, 2 Allée Konrad Roentgen, 67084 Strasbourg, France.,Unité Pathogenèse des Infections Vasculaires, Institut Pasteur, 24-28 rue du Docteur-Roux, 75015 Paris, France
| | - Philippe J Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, INSERM U1202, 24-28 rue du Docteur-Roux, 75015 Paris, France.,Chaire de Microbiologie et Maladies Infectieuses, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris, France
| | - F-X Campbell-Valois
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, INSERM U1202, 24-28 rue du Docteur-Roux, 75015 Paris, France.,The Host-Microbe Interactions Laboratory, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 150 Louis-Pasteur private, Ottawa, ON, K1N 6N5, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Rd, Ottawa, ON, K1N 6N5, Canada
| |
Collapse
|
37
|
The Antiactivator of Type III Secretion, OspD1, Is Transcriptionally Regulated by VirB and H-NS from Remote Sequences in Shigella flexneri. J Bacteriol 2020; 202:JB.00072-20. [PMID: 32123035 DOI: 10.1128/jb.00072-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 02/24/2020] [Indexed: 01/08/2023] Open
Abstract
Shigella species, the causal agents of bacillary dysentery, use a type III secretion system (T3SS) to inject two waves of virulence proteins, known as effectors, into the colonic epithelium to subvert host cell machinery. Prior to host cell contact and secretion of the first wave of T3SS effectors, OspD1, an effector and antiactivator protein, prevents premature production of the second wave of effectors. Despite this important role, regulation of the ospD1 gene is not well understood. While ospD1 belongs to the large regulon of VirB, a transcriptional antisilencing protein that counters silencing mediated by the histone-like nucleoid structuring protein H-NS, it remains unclear if VirB directly or indirectly regulates ospD1 Additionally, it is not known if ospD1 is regulated by H-NS. Here, we identify the primary ospD1 transcription start site (+1) and show that the ospD1 promoter is remotely regulated by both VirB and H-NS. Our findings demonstrate that VirB regulation of ospD1 requires at least one of the two newly identified VirB regulatory sites, centered at -978 and -1270 relative to the ospD1 +1. Intriguingly, one of these sites lies on a 193-bp sequence found in three conserved locations on the large virulence plasmids of Shigella The region required for H-NS-dependent silencing of ospD1 lies between -1120 and -820 relative to the ospD1 +1. Thus, our study provides further evidence that cis-acting regulatory sequences for transcriptional antisilencers and silencers, such as VirB and H-NS, can lie far upstream of the canonical bacterial promoter region (i.e., -250 to +1).IMPORTANCE Transcriptional silencing and antisilencing mechanisms regulate virulence gene expression in many important bacterial pathogens. In Shigella species, plasmid-borne virulence genes, such as those encoding the type III secretion system (T3SS), are silenced by the histone-like nucleoid structuring protein H-NS and antisilenced by VirB. Previous work at the plasmid-borne icsP locus revealed that VirB binds to a remotely located cis-acting regulatory site to relieve transcriptional silencing mediated by H-NS. Here, we characterize a second example of remote VirB antisilencing at ospD1, which encodes a T3SS antiactivator and effector. Our study highlights that remote transcriptional silencing and antisilencing occur more frequently in Shigella than previously thought, and it raises the possibility that long-range transcriptional regulation in bacteria is commonplace.
Collapse
|
38
|
Cervantes-Rivera R, Tronnet S, Puhar A. Complete genome sequence and annotation of the laboratory reference strain Shigella flexneri serotype 5a M90T and genome-wide transcriptional start site determination. BMC Genomics 2020; 21:285. [PMID: 32252626 PMCID: PMC7132871 DOI: 10.1186/s12864-020-6565-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 02/07/2020] [Indexed: 01/19/2023] Open
Abstract
Background Shigella is a Gram-negative facultative intracellular bacterium that causes bacillary dysentery in humans. Shigella invades cells of the colonic mucosa owing to its virulence plasmid-encoded Type 3 Secretion System (T3SS), and multiplies in the target cell cytosol. Although the laboratory reference strain S. flexneri serotype 5a M90T has been extensively used to understand the molecular mechanisms of pathogenesis, its complete genome sequence is not available, thereby greatly limiting studies employing high-throughput sequencing and systems biology approaches. Results We have sequenced, assembled, annotated and manually curated the full genome of S. flexneri 5a M90T. This yielded two complete circular contigs, the chromosome and the virulence plasmid (pWR100). To obtain the genome sequence, we have employed long-read PacBio DNA sequencing followed by polishing with Illumina RNA-seq data. This provides a new hybrid strategy to prepare gapless, highly accurate genome sequences, which also cover AT-rich tracks or repetitive sequences that are transcribed. Furthermore, we have performed genome-wide analysis of transcriptional start sites (TSS) and determined the length of 5′ untranslated regions (5′-UTRs) at typical culture conditions for the inoculum of in vitro infection experiments. We identified 6723 primary TSS (pTSS) and 7328 secondary TSS (sTSS). The S. flexneri 5a M90T annotated genome sequence and the transcriptional start sites are integrated into RegulonDB (http://regulondb.ccg.unam.mx) and RSAT (http://embnet.ccg.unam.mx/rsat/) databases to use their analysis tools in the S. flexneri 5a M90T genome. Conclusions We provide the first complete genome for S. flexneri serotype 5a, specifically the laboratory reference strain M90T. Our work opens the possibility of employing S. flexneri M90T in high-quality systems biology studies such as transcriptomic and differential expression analyses or in genome evolution studies. Moreover, the catalogue of TSS that we report here can be used in molecular pathogenesis studies as a resource to know which genes are transcribed before infection of host cells. The genome sequence, together with the analysis of transcriptional start sites, is also a valuable tool for precise genetic manipulation of S. flexneri 5a M90T. Further, we present a new hybrid strategy to prepare gapless, highly accurate genome sequences. Unlike currently used hybrid strategies combining long- and short-read DNA sequencing technologies to maximize accuracy, our workflow using long-read DNA sequencing and short-read RNA sequencing provides the added value of using non-redundant technologies, which yield distinct, exploitable datasets.
Collapse
Affiliation(s)
- Ramón Cervantes-Rivera
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), 901 87 Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), 901 87, Umeå, Sweden.,Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden
| | - Sophie Tronnet
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), 901 87 Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), 901 87, Umeå, Sweden.,Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden
| | - Andrea Puhar
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), 901 87 Umeå, Sweden. .,Umeå Centre for Microbial Research (UCMR), 901 87, Umeå, Sweden. .,Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden.
| |
Collapse
|
39
|
Abstract
Plasmids have a major role in the development of disease caused by enteric bacterial pathogens. Virulence plasmids are usually large (>40 kb) low copy elements and encode genes that promote host-pathogen interactions. Although virulence plasmids provide advantages to bacteria in specific conditions, they often impose fitness costs on their host. In this Review, we discuss virulence plasmids in Enterobacteriaceae that are important causes of diarrhoea in humans, Shigella spp., Salmonella spp., Yersinia spp and pathovars of Escherichia coli. We contrast these plasmids with those that are routinely used in the laboratory and outline the mechanisms by which virulence plasmids are maintained in bacterial populations. We highlight examples of virulence plasmids that encode multiple mechanisms for their maintenance (for example, toxin-antitoxin and partitioning systems) and speculate on how these might contribute to their propagation and success.
Collapse
|
40
|
Liu S, Feng J, Pu J, Xu X, Lu S, Yang J, Wang Y, Jin D, Du X, Meng X, Luo X, Sun H, Xiong Y, Ye C, Lan R, Xu J. Genomic and molecular characterisation of Escherichia marmotae from wild rodents in Qinghai-Tibet plateau as a potential pathogen. Sci Rep 2019; 9:10619. [PMID: 31337784 PMCID: PMC6650469 DOI: 10.1038/s41598-019-46831-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 07/03/2019] [Indexed: 12/25/2022] Open
Abstract
Wildlife is a reservoir of emerging infectious diseases of humans and domestic animals. Marmota himalayana mainly resides 2800-4000 m above sea level in the Qinghai-Tibetan Plateau, and is the primary animal reservoir of plague pathogen Yersinia pestis. Recently we isolated a new species, Escherichia marmotae from the faeces of M. himalayana. In this study we characterised E. marmotae by genomic analysis and in vitro virulence testing to determine its potential as a human pathogen. We sequenced the genomes of the seven E. marmotae strains and found that they contained a plasmid that carried a Shigella-like type III secretion system (T3SS) and their effectors, and shared the same O antigen gene cluster as Shigella dysenterae 8 and E. coli O38. We also showed that E. marmotae was invasive to HEp-2 cells although it was much less invasive than Shigella. Thus E. marmotae is likely to be an invasive pathogen. However, E. marmotae has a truncated IpaA invasin, and lacks the environmental response regulator VirF and the IcsA-actin based intracellular motility, rendering it far less invasive in comparison to Shigella. E. marmotae also carried a diverse set of virulence factors in addition to the T3SS, including an IS1414 encoded enterotoxin gene astA with 37 copies, E. coli virulence genes lifA/efa, cif, and epeA, and the sfp gene cluster, Yersinia T3SS effector yopJ, one Type II secretion system and two Type VI secretion systems. Therefore, E. marmotae is a potential invasive pathogen.
Collapse
Affiliation(s)
- Sha Liu
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China.,Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China
| | - Jie Feng
- Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Beijing, 100101, China
| | - Ji Pu
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Xuefang Xu
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Shan Lu
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Jing Yang
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Yiting Wang
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Dong Jin
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Xiaochen Du
- Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Beijing, 100101, China
| | - Xiangli Meng
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Xia Luo
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Hui Sun
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Yanwen Xiong
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Changyun Ye
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China
| | - Ruiting Lan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia.
| | - Jianguo Xu
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center of Diagnosis and Treatment of Infectious Diseases, National Institute of Communicable Disease Control and Prevention, Chinese Center of Disease Control and Prevention, Beijing, 102206, China. .,Shanghai Institute of Emerging and Re-emerging infectious diseases, Shanghai Public Health Clinical Center, Shanghai, 201508, China.
| |
Collapse
|
41
|
Abstract
PURPOSE OF REVIEW Diarrhoea is a major global health problem, and recent studies have confirmed Shigella as a major contributor to this burden. Here, we review recent advances in Shigella research; focusing on their epidemiology, pathogenesis, antimicrobial resistance, and the role of the gut microbiome during infection. RECENT FINDINGS Enhanced epidemiological data, combined with new generation diagnostics, has highlighted a greater burden of Shigella disease than was previously estimated, which is not restricted to vulnerable populations in low-middle income countries. As we gain an ever more detailed insight into the orchestrated mechanisms that Shigella exploit to trigger infection, we can also begin to appreciate the complex role of the gut microbiome in preventing and inducing such infections. The use of genomics, in combination with epidemiological data and laboratory investigations, has unravelled the evolution and spread of various species. Such measures have identified resistance to antimicrobials as a key contributor to the success of specific clones. SUMMARY We need to apply novel findings towards sustainable approaches for treating and preventing Shigella infections. Vaccines and alternative treatments are under development and may offer an opportunity to reduce the burden of Shigella disease and restrict the mobility of antimicrobial resistant clones.
Collapse
|
42
|
Liu G, Pilla G, Tang CM. Shigella host: Pathogen interactions: Keeping bacteria in the loop. Cell Microbiol 2019; 21:e13062. [PMID: 31134722 DOI: 10.1111/cmi.13062] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/05/2019] [Accepted: 05/20/2019] [Indexed: 12/15/2022]
Abstract
Shigella spp. are Gram-negative enteric pathogens and the leading cause of bacterial dysentery worldwide. Since the discovery more than three decades ago that the large virulence plasmid of Shigella is essential for pathogenesis, our understanding of how the bacterium orchestrates inflammation and tissue destruction at the mucosal surface has been informed by studies employing the rabbit ileal loop model. Here, we outline how Phillippe Sansonetti, together with his co-workers and collaborators, exploited this model to provide a holistic view of how Shigella survives in the intestinal tract, traverses the intestinal epithelial barrier, and manipulates the host immune system to cause disease.
Collapse
Affiliation(s)
- Guangyu Liu
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Giulia Pilla
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| |
Collapse
|
43
|
The Autotransporter IcsA Promotes Shigella flexneri Biofilm Formation in the Presence of Bile Salts. Infect Immun 2019; 87:IAI.00861-18. [PMID: 30988059 DOI: 10.1128/iai.00861-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/09/2019] [Indexed: 12/25/2022] Open
Abstract
Shigella flexneri is an intracellular bacterial pathogen that invades epithelial cells in the colonic mucosa, leading to bloody diarrhea. A previous study showed that S. flexneri forms biofilms in the presence of bile salts, through an unknown mechanism. Here, we investigated the potential role of adhesin-like autotransporter proteins in S. flexneri biofilm formation. BLAST search analysis revealed that the S. flexneri 2457T genome harbors 4 genes, S1242, S1289, S2406, and icsA, encoding adhesin-like autotransporter proteins. Deletion mutants of the S1242, S1289, S2406 and icsA genes were generated and tested for biofilm formation. Phenotypic analysis of the mutant strains revealed that disruption of icsA abolished bile salt-induced biofilm formation. IcsA is an outer membrane protein secreted at the bacterial pole that is required for S. flexneri actin-based motility during intracellular infection. In extracellular biofilms, IcsA was also secreted at the bacterial pole and mediated bacterial cell-cell contacts and aggregative growth in the presence of bile salts. Dissecting individual roles of bile salts showed that deoxycholate is a robust biofilm inducer compared to cholate. The release of the extracellular domain of IcsA through IcsP-mediated cleavage was greater in the presence of cholate, suggesting that the robustness of biofilm formation was inversely correlated with IcsA processing. Accordingly, deletion of icsP abrogated IcsA processing in biofilms and enhanced biofilm formation.
Collapse
|
44
|
Parajuli P, Rajput MI, Verma NK. Plasmids of Shigella flexneri serotype 1c strain Y394 provide advantages to bacteria in the host. BMC Microbiol 2019; 19:86. [PMID: 31035948 PMCID: PMC6489325 DOI: 10.1186/s12866-019-1455-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 04/11/2019] [Indexed: 11/29/2022] Open
Abstract
Background Shigella flexneri has an extremely complex genome with a significant number of virulence traits acquired by mobile genetic elements including bacteriophages and plasmids. S. flexneri serotype 1c is an emerging etiological agent of bacillary dysentery in developing countries. In this study, the complete nucleotide sequence of two plasmids of S. flexneri serotype 1c strain Y394 was determined and analysed. Results The plasmid pINV-Y394 is an invasive or virulence plasmid of size 221,293 bp composed of a large number of insertion sequences (IS), virulence genes, regulatory and maintenance genes. Three hundred and twenty-eight open reading frames (ORFs) were identified in pINV-Y394, of which about a half (159 ORFs) were identified as IS elements. Ninety-seven ORFs were related to characterized genes (majority of which are associated with virulence and their regulons), and 72 ORFs were uncharacterized or hypothetical genes. The second plasmid pNV-Y394 is of size 10,866 bp and encodes genes conferring resistance against multiple antibiotics of clinical importance. The multidrug resistance gene cassette consists of tetracycline resistance gene tetA, streptomycin resistance gene strA-strB and sulfonamide-resistant dihydropteroate synthase gene sul2. Conclusions These two plasmids together play a key role in the fitness of Y394 in the host environment. The findings from this study indicate that the pathogenic S. flexneri is a highly niche adaptive pathogen which is able to co-evolve with its host and respond to the selection pressure in its environment. Electronic supplementary material The online version of this article (10.1186/s12866-019-1455-1) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Pawan Parajuli
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Munazza I Rajput
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Naresh K Verma
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, ACT, Australia.
| |
Collapse
|
45
|
McVicker G, Hollingshead S, Pilla G, Tang CM. Maintenance of the virulence plasmid in Shigella flexneri is influenced by Lon and two functional partitioning systems. Mol Microbiol 2019; 111:1355-1366. [PMID: 30767313 PMCID: PMC6519299 DOI: 10.1111/mmi.14225] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2019] [Indexed: 11/30/2022]
Abstract
Members of the genus Shigella carry a large plasmid, pINV, which is essential for virulence. In Shigella flexneri, pINV harbours three toxin‐antitoxin (TA) systems, CcdAB, GmvAT and VapBC that promote vertical transmission of the plasmid. Type II TA systems, such as those on pINV, consist of a toxic protein and protein antitoxin. Selective degradation of the antitoxin by proteases leads to the unopposed action of the toxin once genes encoding a TA system have been lost, such as following failure to inherit a plasmid harbouring a TA system. Here, we investigate the role of proteases in the function of the pINV TA systems and demonstrate that Lon, but not ClpP, is required for their activity during plasmid stability. This provides the first evidence that acetyltransferase family TA systems, such as GmvAT, can be regulated by Lon. Interestingly, S. flexneri pINV also harbours two putative partitioning systems, ParAB and StbAB. We show that both systems are functional for plasmid maintenance although their activity is masked by other systems on pINV. Using a model vector based on the pINV replicon, we observe temperature‐dependent differences between the two partitioning systems that contribute to our understanding of the maintenance of virulence in Shigella species.
Collapse
Affiliation(s)
- Gareth McVicker
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Sarah Hollingshead
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Giulia Pilla
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| |
Collapse
|
46
|
Silué N, Marcantonio E, Campbell-Valois FX. RNA-Seq analysis of the T3SA regulon in Shigella flexneri reveals two new chromosomal genes upregulated in the on-state. Methods 2019; 176:71-81. [PMID: 30905752 DOI: 10.1016/j.ymeth.2019.03.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/11/2019] [Accepted: 03/20/2019] [Indexed: 02/06/2023] Open
Abstract
Shigella spp. are enterobacteria that invade human colonic mucosal cells using their Type Three Secretion Apparatus (T3SA). Shigella spp. possess a large plasmid that encodes most of its virulence factors and has been the focus of seminal work that defined the T3SA regulon. Thus, a global assessment of the transcriptional response regulated by the T3SA has been lacking. Herein we used RNA-Seq to identify genes that are differentially expressed when the T3SA is active (on-state) versus inactive (off-state). The quality of the RNA-Seq dataset was validated by its correlation with a prior microarray study. Using novel insights about the expression of non-coding regions, bioinformatic tools and experimentations, we demonstrated the existence of six operons and evidence that ipaH2.5 is a pseudogene. In addition, 86 chromosomal genes were downregulated in the on-state including several non-coding transcripts corresponding to short antisense RNA embedded in the 16S and 23S RNA genes, and 40 coding transcripts, whose cognate proteins were highly connected at the genetic and biochemical levels. Finally, we identified two novel chromosomal genes dubbed gem1 and gem3, which were upregulated in the on-state similarly to genes belonging to the T3SA regulon. The latter findings were validated on biological triplicates by droplet digital PCR. To our knowledge gem1 and gem3 are the first chromosomal members of the T3SA regulon that have no homologs on the plasmid. Our approach provides a path to optimizing RNA-Seq studies in case of bacterial models that had previously been the subject of medium to large scale studies.
Collapse
Affiliation(s)
- Navoun Silué
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Endrei Marcantonio
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - F-X Campbell-Valois
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| |
Collapse
|
47
|
Miller KA, Tomberlin KF, Dziejman M. Vibrio variations on a type three theme. Curr Opin Microbiol 2019; 47:66-73. [PMID: 30711745 DOI: 10.1016/j.mib.2018.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/06/2018] [Accepted: 12/16/2018] [Indexed: 11/18/2022]
Abstract
Mounting evidence suggests that Type 3 Secretion Systems (T3SS) are widespread among Vibrio species, and are present in strains isolated from diverse sources such as human clinical infections, environmental reservoirs, and diseased marine life. Experiments evaluating Vibrio parahaemolyticus and Vibrio cholerae T3SS mediated virulence suggest that Vibrio T3SS pathogenicity islands have a tripartite composition. A conserved 'core' region encodes functions essential for colonization and disease in vivo, including modulation of innate immune signaling pathways and actin dynamics, whereas regions flanking core sequences are variable among strains and encode effector proteins performing a diverse array of activities. Characterizing novel functions associated with Vibrio-specific effectors is, therefore, essential for understanding how vibrios employ T3SS mechanisms to cause disease in a broad range of hosts and how T3SS island composition potentially defines species-specific disease.
Collapse
Affiliation(s)
- Kelly A Miller
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States
| | - Katharine F Tomberlin
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States
| | - Michelle Dziejman
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States.
| |
Collapse
|
48
|
Bastedo DP, Lo T, Laflamme B, Desveaux D, Guttman DS. Diversity and Evolution of Type III Secreted Effectors: A Case Study of Three Families. Curr Top Microbiol Immunol 2019; 427:201-230. [DOI: 10.1007/82_2019_165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
49
|
Dorman MJ, Dorman CJ. Regulatory Hierarchies Controlling Virulence Gene Expression in Shigella flexneri and Vibrio cholerae. Front Microbiol 2018; 9:2686. [PMID: 30473684 PMCID: PMC6237886 DOI: 10.3389/fmicb.2018.02686] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/22/2018] [Indexed: 12/13/2022] Open
Abstract
Gram-negative enteropathogenic bacteria use a variety of strategies to cause disease in the human host and gene regulation in some form is typically a part of the strategy. This article will compare the toxin-based infection strategy used by the non-invasive pathogen Vibrio cholerae, the etiological agent in human cholera, with the invasive approach used by Shigella flexneri, the cause of bacillary dysentery. Despite the differences in the mechanisms by which the two pathogens cause disease, they use environmentally-responsive regulatory hierarchies to control the expression of genes that have some features, and even some components, in common. The involvement of AraC-like transcription factors, the integration host factor, the Factor for inversion stimulation, small regulatory RNAs, the RNA chaperone Hfq, horizontal gene transfer, variable DNA topology and the need to overcome the pervasive silencing of transcription by H-NS of horizontally acquired genes are all shared features. A comparison of the regulatory hierarchies in these two pathogens illustrates some striking cross-species similarities and differences among mechanisms coordinating virulence gene expression. S. flexneri, with its low infectious dose, appears to use a strategy that is centered on the individual bacterial cell, whereas V. cholerae, with a community-based, quorum-dependent approach and an infectious dose that is several orders of magnitude higher, seems to rely more on the actions of a bacterial collective.
Collapse
Affiliation(s)
- Matthew J Dorman
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Charles J Dorman
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
| |
Collapse
|
50
|
Salazar AN, Abeel T. Approximate, simultaneous comparison of microbial genome architectures via syntenic anchoring of quiver representations. Bioinformatics 2018; 34:i732-i742. [PMID: 30423098 PMCID: PMC6129293 DOI: 10.1093/bioinformatics/bty614] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Motivation A long-standing limitation in comparative genomic studies is the dependency on a reference genome, which hinders the spectrum of genetic diversity that can be identified across a population of organisms. This is especially true in the microbial world where genome architectures can significantly vary. There is therefore a need for computational methods that can simultaneously analyze the architectures of multiple genomes without introducing bias from a reference. Results In this article, we present Ptolemy: a novel method for studying the diversity of genome architectures-such as structural variation and pan-genomes-across a collection of microbial assemblies without the need of a reference. Ptolemy is a 'top-down' approach to compare whole genome assemblies. Genomes are represented as labeled multi-directed graphs-known as quivers-which are then merged into a single, canonical quiver by identifying 'gene anchors' via synteny analysis. The canonical quiver represents an approximate, structural alignment of all genomes in a given collection encoding structural variation across (sub-) populations within the collection. We highlight various applications of Ptolemy by analyzing structural variation and the pan-genomes of different datasets composing of Mycobacterium, Saccharomyces, Escherichia and Shigella species. Our results show that Ptolemy is flexible and can handle both conserved and highly dynamic genome architectures. Ptolemy is user-friendly-requires only FASTA-formatted assembly along with a corresponding GFF-formatted file-and resource-friendly-can align 24 genomes in ∼10 mins with four CPUs and <2 GB of RAM. Availability and implementation Github: https://github.com/AbeelLab/ptolemy. Supplementary information Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
- Alex N Salazar
- Delft Bioinformatics Lab, Delft University of Technology, Delft, The Netherlands
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Thomas Abeel
- Delft Bioinformatics Lab, Delft University of Technology, Delft, The Netherlands
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| |
Collapse
|