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Rostovsky I, Wieler U, Kuzmina A, Taube R, Sal-Man N. Secretion of functional interferon by the type 3 secretion system of enteropathogenic Escherichia coli. Microb Cell Fact 2024; 23:163. [PMID: 38824527 PMCID: PMC11144349 DOI: 10.1186/s12934-024-02397-y] [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: 02/12/2024] [Accepted: 04/18/2024] [Indexed: 06/03/2024] Open
Abstract
BACKGROUND Type I interferons (IFN-I)-a group of cytokines with immunomodulatory, antiproliferative, and antiviral properties-are widely used as therapeutics for various cancers and viral diseases. Since IFNs are proteins, they are highly susceptible to degradation by proteases and by hydrolysis in the strong acid environment of the stomach, and they are therefore administered parenterally. In this study, we examined whether the intestinal bacterium, enteropathogenic Escherichia coli (EPEC), can be exploited for oral delivery of IFN-Is. EPEC survives the harsh conditions of the stomach and, upon reaching the small intestine, expresses a type III secretion system (T3SS) that is used to translocate effector proteins across the bacterial envelope into the eukaryotic host cells. RESULTS In this study, we developed an attenuated EPEC strain that cannot colonize the host but can secrete functional human IFNα2 variant through the T3SS. We found that this bacteria-secreted IFN exhibited antiproliferative and antiviral activities similar to commercially available IFN. CONCLUSION These findings present a potential novel approach for the oral delivery of IFN via secreting bacteria.
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Affiliation(s)
- Irina Rostovsky
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, 84105, Beer-Sheva, Israel
| | - Uri Wieler
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, 84105, Beer-Sheva, Israel
| | - Alona Kuzmina
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, 84105, Beer-Sheva, Israel
| | - Ran Taube
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, 84105, Beer-Sheva, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, 84105, Beer-Sheva, Israel.
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2
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Gershberg J, Morhaim M, Rostrovsky I, Eichler J, Sal-Man N. The sequence of events of enteropathogenic E. coli's type III secretion system translocon assembly. iScience 2024; 27:109108. [PMID: 38375228 PMCID: PMC10875159 DOI: 10.1016/j.isci.2024.109108] [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: 08/23/2023] [Revised: 12/17/2023] [Accepted: 01/31/2024] [Indexed: 02/21/2024] Open
Abstract
Many bacterial pathogens employ the type III secretion system (T3SS), a specialized complex that transports effector proteins that manipulate various cellular processes. The T3SS forms a translocon pore within the host-cell membrane consisting of two secreted proteins that transition from a soluble state into a transmembrane complex. Still, the exact sequence of events leading to the formation of a membranous functional pore remains uncertain. Here, we utilized the translocon proteins of enteropathogenic E. coli (EPEC) to investigate the sequence of those steps leading to translocon assembly, including self-oligomerization, hetero-oligomerization, interprotein interaction, and membrane insertion. We found that in EPEC, EspD (SctE) plays a dominant role in pore formation as it assembles into an oligomeric state, regardless of pH, membrane contact, or the presence of EspB (SctB). Subsequently, EspB subunits integrate into EspD homo-oligomers to create EspB-EspD hetero-oligomers that adopt a transmembrane orientation to create a functional pore complex.
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Affiliation(s)
- Jenia Gershberg
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - May Morhaim
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Irina Rostrovsky
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Jerry Eichler
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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3
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Lisboa J, Pereira C, Pinto RD, Rodrigues IS, Pereira LMG, Pinheiro B, Oliveira P, Pereira PJB, Azevedo JE, Durand D, Benz R, do Vale A, Dos Santos NMS. Unconventional structure and mechanisms for membrane interaction and translocation of the NF-κB-targeting toxin AIP56. Nat Commun 2023; 14:7431. [PMID: 37973928 PMCID: PMC10654918 DOI: 10.1038/s41467-023-43054-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: 05/15/2023] [Accepted: 10/30/2023] [Indexed: 11/19/2023] Open
Abstract
Bacterial AB toxins are secreted key virulence factors that are internalized by target cells through receptor-mediated endocytosis, translocating their enzymatic domain to the cytosol from endosomes (short-trip) or the endoplasmic reticulum (long-trip). To accomplish this, bacterial AB toxins evolved a multidomain structure organized into either a single polypeptide chain or non-covalently associated polypeptide chains. The prototypical short-trip single-chain toxin is characterized by a receptor-binding domain that confers cellular specificity and a translocation domain responsible for pore formation whereby the catalytic domain translocates to the cytosol in an endosomal acidification-dependent way. In this work, the determination of the three-dimensional structure of AIP56 shows that, instead of a two-domain organization suggested by previous studies, AIP56 has three-domains: a non-LEE encoded effector C (NleC)-like catalytic domain associated with a small middle domain that contains the linker-peptide, followed by the receptor-binding domain. In contrast to prototypical single-chain AB toxins, AIP56 does not comprise a typical structurally complex translocation domain; instead, the elements involved in translocation are scattered across its domains. Thus, the catalytic domain contains a helical hairpin that serves as a molecular switch for triggering the conformational changes necessary for membrane insertion only upon endosomal acidification, whereas the middle and receptor-binding domains are required for pore formation.
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Affiliation(s)
- Johnny Lisboa
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal.
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal.
| | - Cassilda Pereira
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Rute D Pinto
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
| | - Inês S Rodrigues
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Liliana M G Pereira
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
| | - Bruno Pinheiro
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
- Doctoral Program in Molecular and Cell Biology (MCbiology), Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto, Porto, Portugal
| | - Pedro Oliveira
- EPIUnit, ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Pedro José Barbosa Pereira
- Biomolecular Structure Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
- Macromolecular Structure Group, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Jorge E Azevedo
- ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
- Organelle Biogenesis and Function, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
- Organelle Biogenesis and Function, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Dominique Durand
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Roland Benz
- Science Faculty, Constructor University, Bremen, Germany
| | - Ana do Vale
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Nuno M S Dos Santos
- Fish Immunology and Vaccinology Group, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal.
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal.
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Nandi I, Aroeti B. Mitogen-Activated Protein Kinases (MAPKs) and Enteric Bacterial Pathogens: A Complex Interplay. Int J Mol Sci 2023; 24:11905. [PMID: 37569283 PMCID: PMC10419152 DOI: 10.3390/ijms241511905] [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: 06/18/2023] [Revised: 07/19/2023] [Accepted: 07/19/2023] [Indexed: 08/13/2023] Open
Abstract
Diverse extracellular and intracellular cues activate mammalian mitogen-activated protein kinases (MAPKs). Canonically, the activation starts at cell surface receptors and continues via intracellular MAPK components, acting in the host cell nucleus as activators of transcriptional programs to regulate various cellular activities, including proinflammatory responses against bacterial pathogens. For instance, binding host pattern recognition receptors (PRRs) on the surface of intestinal epithelial cells to bacterial pathogen external components trigger the MAPK/NF-κB signaling cascade, eliciting cytokine production. This results in an innate immune response that can eliminate the bacterial pathogen. However, enteric bacterial pathogens evolved sophisticated mechanisms that interfere with such a response by delivering virulent proteins, termed effectors, and toxins into the host cells. These proteins act in numerous ways to inactivate or activate critical components of the MAPK signaling cascades and innate immunity. The consequence of such activities could lead to successful bacterial colonization, dissemination, and pathogenicity. This article will review enteric bacterial pathogens' strategies to modulate MAPKs and host responses. It will also discuss findings attempting to develop anti-microbial treatments by targeting MAPKs.
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Affiliation(s)
| | - Benjamin Aroeti
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190410, Israel;
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Pillay TD, Hettiarachchi SU, Gan J, Diaz-Del-Olmo I, Yu XJ, Muench JH, Thurston TL, Pearson JS. Speaking the host language: how Salmonella effector proteins manipulate the host. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001342. [PMID: 37279149 PMCID: PMC10333799 DOI: 10.1099/mic.0.001342] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 05/10/2023] [Indexed: 06/08/2023]
Abstract
Salmonella injects over 40 virulence factors, termed effectors, into host cells to subvert diverse host cellular processes. Of these 40 Salmonella effectors, at least 25 have been described as mediating eukaryotic-like, biochemical post-translational modifications (PTMs) of host proteins, altering the outcome of infection. The downstream changes mediated by an effector's enzymatic activity range from highly specific to multifunctional, and altogether their combined action impacts the function of an impressive array of host cellular processes, including signal transduction, membrane trafficking, and both innate and adaptive immune responses. Salmonella and related Gram-negative pathogens have been a rich resource for the discovery of unique enzymatic activities, expanding our understanding of host signalling networks, bacterial pathogenesis as well as basic biochemistry. In this review, we provide an up-to-date assessment of host manipulation mediated by the Salmonella type III secretion system injectosome, exploring the cellular effects of diverse effector activities with a particular focus on PTMs and the implications for infection outcomes. We also highlight activities and functions of numerous effectors that remain poorly characterized.
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Affiliation(s)
- Timesh D. Pillay
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Sahampath U. Hettiarachchi
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Jiyao Gan
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Ines Diaz-Del-Olmo
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
| | - Xiu-Jun Yu
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
| | - Janina H. Muench
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Teresa L.M. Thurston
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College, London SW7 2AZ, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Jaclyn S. Pearson
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
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6
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Ta A, Ricci-Azevedo R, Vasudevan SO, Wright SS, Kumari P, Havira MS, Surendran Nair M, Rathinam VA, Vanaja SK. A bacterial autotransporter impairs innate immune responses by targeting the transcription factor TFE3. Nat Commun 2023; 14:2035. [PMID: 37041208 PMCID: PMC10090168 DOI: 10.1038/s41467-023-37812-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 03/29/2023] [Indexed: 04/13/2023] Open
Abstract
Type I interferons (IFNs) are consequential cytokines in antibacterial defense. Whether and how bacterial pathogens inhibit innate immune receptor-driven type I IFN expression remains mostly unknown. By screening a library of enterohemorrhagic Escherichia coli (EHEC) mutants, we uncovered EhaF, an uncharacterized protein, as an inhibitor of innate immune responses including IFNs. Further analyses identified EhaF as a secreted autotransporter-a type of bacterial secretion system with no known innate immune-modulatory function-that translocates into host cell cytosol and inhibit IFN response to EHEC. Mechanistically, EhaF interacts with and inhibits the MiT/TFE family transcription factor TFE3 resulting in impaired TANK phosphorylation and consequently, reduced IRF3 activation and type I IFN expression. Notably, EhaF-mediated innate immune suppression promotes EHEC colonization and pathogenesis in vivo. Overall, this study has uncovered a previously unknown autotransporter-based bacterial strategy that targets a specific transcription factor to subvert innate host defense.
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Affiliation(s)
- Atri Ta
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Rafael Ricci-Azevedo
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Swathy O Vasudevan
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Skylar S Wright
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Puja Kumari
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave, Farmington, CT, 06030, USA
| | | | - Meera Surendran Nair
- Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA, 16802, USA
| | - Vijay A Rathinam
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Sivapriya Kailasan Vanaja
- Department of Immunology, UConn Health School of Medicine, 263 Farmington Ave, Farmington, CT, 06030, USA.
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7
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Braverman D, Gershberg J, Sal-Man N. The transmembrane domains of the type III secretion system effector Tir are involved in its secretion and cellular activities. Front Cell Infect Microbiol 2023; 13:1103552. [PMID: 36864885 PMCID: PMC9971567 DOI: 10.3389/fcimb.2023.1103552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 02/01/2023] [Indexed: 02/16/2023] Open
Abstract
Introduction Enteropathogenic Escherichia coli (EPEC) is a diarrheagenic pathogen and one of the major causes of gastrointestinal illness in developing countries. EPEC, similar to many other Gram-negative bacterial pathogens, possesses essential virulence machinery called the type III secretion system (T3SS) that enables the injection of effector proteins from the bacteria into the host cytoplasm. Of these, the translocated intimin receptor (Tir) is the first effector to be injected, and its activity is essential for the formation of attaching and effacing lesions, the hallmark of EPEC colonization. Tir belongs to a unique group of transmembrane domain (TMD)-containing secreted proteins, which have two conflicting destination indications, one for bacterial membrane integration and another for protein secretion. In this study, we examined whether TMDs participate in the secretion, translocation, and function of Tir in host cells. Methods We created Tir TMD variants with the original or alternative TMD sequence. Results We found that the C-terminal TMD of Tir (TMD2) is critical for the ability of Tir to escape integration into the bacterial membrane. However, the TMD sequence was not by itself sufficient and its effect was context-dependent. Moreover, the N-terminal TMD of Tir (TMD1) was important for the postsecretion function of Tir at the host cell. Discussion Taken together, our study further supports the hypothesis that the TMD sequences of translocated proteins encode information crucial for protein secretion and their postsecretion function.
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Affiliation(s)
- Dor Braverman
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Jenia Gershberg
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Robinson LA, Collins ACZ, Murphy RA, Davies JC, Allsopp LP. Diversity and prevalence of type VI secretion system effectors in clinical Pseudomonas aeruginosa isolates. Front Microbiol 2023; 13:1042505. [PMID: 36687572 PMCID: PMC9846239 DOI: 10.3389/fmicb.2022.1042505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 11/23/2022] [Indexed: 01/06/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen and a major driver of morbidity and mortality in people with Cystic Fibrosis (CF). The Type VI secretion system (T6SS) is a molecular nanomachine that translocates effectors across the bacterial membrane into target cells or the extracellular environment enabling intermicrobial interaction. P. aeruginosa encodes three T6SS clusters, the H1-, H2- and H3-T6SS, and numerous orphan islands. Genetic diversity of T6SS-associated effectors in P. aeruginosa has been noted in reference strains but has yet to be explored in clinical isolates. Here, we perform a comprehensive bioinformatic analysis of the pangenome and T6SS effector genes in 52 high-quality clinical P. aeruginosa genomes isolated from CF patients and housed in the Personalised Approach to P. aeruginosa strain repository. We confirm that the clinical CF isolate pangenome is open and principally made up of accessory and unique genes that may provide strain-specific advantages. We observed genetic variability in some effector/immunity encoding genes and show that several well-characterised vgrG and PAAR islands are absent from numerous isolates. Our analysis shows clear evidence of disruption to T6SS genomic loci through transposon, prophage, and mobile genetic element insertions. We identified an orphan vgrG island in P. aeruginosa strain PAK and five clinical isolates using in silico analysis which we denote vgrG7, predicting a gene within this cluster to encode a Tle2 lipase family effector. Close comparison of T6SS loci in clinical isolates compared to reference P. aeruginosa strain PAO1 revealed the presence of genes encoding eight new T6SS effectors with the following putative functions: cytidine deaminase, lipase, metallopeptidase, NADase, and pyocin. Finally, the prevalence of characterised and putative T6SS effectors were assessed in 532 publicly available P. aeruginosa genomes, which suggests the existence of accessory effectors. Our in silico study of the P. aeruginosa T6SS exposes a level of genetic diversity at T6SS genomic loci not seen to date within P. aeruginosa, particularly in CF isolates. As understanding the effector repertoire is key to identifying the targets of T6SSs and its efficacy, this comprehensive analysis provides a path for future experimental characterisation of these mediators of intermicrobial competition and host manipulation.
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Affiliation(s)
- Luca A. Robinson
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Alice C. Z. Collins
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Ronan A. Murphy
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Jane C. Davies
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Department of Paediatric Respiratory Medicine, Royal Brompton Hospital, London, United Kingdom
| | - Luke P. Allsopp
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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9
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Gorelik O, Rogad A, Holoidovsky L, Meijler MM, Sal-Man N. Indole intercepts the communication between enteropathogenic E. coli and Vibrio cholerae. Gut Microbes 2022; 14:2138677. [PMID: 36519445 PMCID: PMC9635540 DOI: 10.1080/19490976.2022.2138677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Reported numbers of diarrheal samples exhibiting co-infections or multiple infections, with two or more infectious agents, are rising, likely due to advances in bacterial diagnostic techniques. Bacterial species detected in these samples include Vibrio cholerae (V. cholerae) and enteropathogenic Escherichia coli (EPEC), which infect the small intestine and are associated with high mortality rates. It has previously been reported that EPEC exhibit enhanced virulence in the presence of V. cholerae owing to their ability to sense and respond to elevated concentrations of cholera autoinducer 1 (CAI-1), which is the primary quorum-sensing (QS) molecule produced by V. cholerae. In this study, we examined this interspecies bacterial communication in the presence of indole, a major microbiome-derived metabolite found at high concentrations in the human gut. Interestingly, we discovered that although indole did not affect bacterial growth or CAI-1 production, it impaired the ability of EPEC to enhance its virulence activity in response to the presence of V. cholerae. Furthermore, the co-culture of EPEC and V. cholerae in the presence of B. thetaiotaomicron, an indole-producing commensal bacteria, ablated the enhancement of EPEC virulence. Together, these results suggest that microbiome compositions or diets that influence indole gut concentrations may differentially impact the virulence of pathogens and their ability to sense and respond to competing bacteria.
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Affiliation(s)
- Orna Gorelik
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Alona Rogad
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Lara Holoidovsky
- Department of Chemistry, the National Institute for Biotechnology in the Negev Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Michael M. Meijler
- Department of Chemistry, the National Institute for Biotechnology in the Negev Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel,CONTACT Neta Sal-Man The Shraga Segal Department of Microbiology, Immunology, and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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10
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Ciaston I, Dobosz E, Potempa J, Koziel J. The subversion of toll-like receptor signaling by bacterial and viral proteases during the development of infectious diseases. Mol Aspects Med 2022; 88:101143. [PMID: 36152458 PMCID: PMC9924004 DOI: 10.1016/j.mam.2022.101143] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/29/2022] [Accepted: 09/09/2022] [Indexed: 02/05/2023]
Abstract
Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) that respond to pathogen-associated molecular patterns (PAMPs). The recognition of specific microbial ligands by TLRs triggers an innate immune response and also promotes adaptive immunity, which is necessary for the efficient elimination of invading pathogens. Successful pathogens have therefore evolved strategies to subvert and/or manipulate TLR signaling. Both the impairment and uncontrolled activation of TLR signaling can harm the host, causing tissue destruction and allowing pathogens to proliferate, thus favoring disease progression. In this context, microbial proteases are key virulence factors that modify components of the TLR signaling pathway. In this review, we discuss the role of bacterial and viral proteases in the manipulation of TLR signaling, highlighting the importance of these enzymes during the development of infectious diseases.
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Affiliation(s)
- Izabela Ciaston
- Department of Microbiology Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ewelina Dobosz
- Department of Microbiology Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Jan Potempa
- Department of Microbiology Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland; Department of Oral Health and Systemic Disease, University of Louisville School of Dentistry, University of Louisville, Louisville, KY, USA.
| | - Joanna Koziel
- Department of Microbiology Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
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11
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Sanchez-Garrido J, Ruano-Gallego D, Choudhary JS, Frankel G. The type III secretion system effector network hypothesis. Trends Microbiol 2022; 30:524-533. [PMID: 34840074 DOI: 10.1016/j.tim.2021.10.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 10/26/2021] [Accepted: 10/28/2021] [Indexed: 11/18/2022]
Abstract
Type III secretion system (T3SS) effectors are key virulence factors that underpin the infection strategy of many clinically important Gram-negative pathogens, including Salmonella enterica, Shigella spp., enteropathogenic and enterohemorrhagic Escherichia coli and their murine equivalent, Citrobacter rodentium. The cellular processes or proteins targeted by the effectors can be common to multiple pathogens or pathogen-specific. The main approach to understanding T3SS-mediated pathogenesis has been to determine the contribution of one effector at a time, with the aim of piecing together individual functions and unveiling infection mechanisms. However, in contrast to this prevailing approach, simultaneous deletion of multiple effectors revealed that they function as an interconnected network in vivo, uncovering effector codependency and context-dependent effector essentiality. This paradigm shift in T3SS biology is at the heart of this opinion article.
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Affiliation(s)
- Julia Sanchez-Garrido
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK.
| | - David Ruano-Gallego
- Department of Molecular Evolution, Centro de Astrobiología, Instituto Nacional de Técnica Aeroespacial-Consejo Superior de Investigaciones Científicas (INTA-CSIC), Madrid, Spain.
| | - Jyoti S Choudhary
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, UK
| | - Gad Frankel
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
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12
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Deb S, Gokulan CG, Nathawat R, Patel HK, Sonti RV. Suppression of XopQ-XopX-induced immune responses of rice by the type III effector XopG. MOLECULAR PLANT PATHOLOGY 2022; 23:634-648. [PMID: 35150038 PMCID: PMC8995061 DOI: 10.1111/mpp.13184] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/01/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
Effectors that suppress effector-triggered immunity (ETI) are an essential part of the arms race in the co-evolution of bacterial pathogens and their host plants. Xanthomonas oryzae pv. oryzae uses multiple type III secretion system (T3SS) secreted effectors such as XopU, XopV, XopP, XopG, and AvrBs2 to suppress rice immune responses that are induced by the interaction of two other effectors, XopQ and XopX. Here we show that each of these five suppressors can interact individually with both XopQ and XopX. One of the suppressors, XopG, is a predicted metallopeptidase that appears to have been introduced into X. oryzae pv. oryzae by horizontal gene transfer. XopQ and XopX interact with each other in the nucleus while interaction with XopG sequesters them in the cytoplasm. The XopG E76A and XopG E85A mutants are defective in interaction with XopQ and XopX, and are also defective in suppression of XopQ-XopX-mediated immune responses. Both mutations individually affect the virulence-promoting ability of XopG. These results indicate that XopG is important for X. oryzae pv. oryzae virulence and provide insights into the mechanisms by which this protein suppresses ETI in rice.
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Affiliation(s)
- Sohini Deb
- CSIR ‐ Centre for Cellular and Molecular Biology (CSIR‐CCMB)HyderabadIndia
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - C. G. Gokulan
- CSIR ‐ Centre for Cellular and Molecular Biology (CSIR‐CCMB)HyderabadIndia
| | - Rajkanwar Nathawat
- CSIR ‐ Centre for Cellular and Molecular Biology (CSIR‐CCMB)HyderabadIndia
| | - Hitendra K. Patel
- CSIR ‐ Centre for Cellular and Molecular Biology (CSIR‐CCMB)HyderabadIndia
| | - Ramesh V. Sonti
- CSIR ‐ Centre for Cellular and Molecular Biology (CSIR‐CCMB)HyderabadIndia
- Indian Institute of Science Education and Research (IISER) TirupatiTirupatiIndia
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13
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Hu F, Zhang Y, Liu Q, Wang Z. PurA facilitates Edwardsiella piscicida to escape NF-κB signaling activation. FISH & SHELLFISH IMMUNOLOGY 2022; 124:254-260. [PMID: 35395412 DOI: 10.1016/j.fsi.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/01/2022] [Accepted: 04/01/2022] [Indexed: 06/14/2023]
Abstract
The host NF-κB signaling pathway plays critical role in defensing against bacterial infection. However, bacteria also evolve strategies to escape from host clearance. Edwardsiella piscicida is a threatening pathogen in aquaculture, while the molecular mechanism of E. piscicida in inhibiting NF-κB signaling remains largely unknown. Herein, using E. piscicida transposon insertion mutant library combined with a NF-κB luciferase reporter system, we identified forty-six genes of E. piscicida, which were involved in inhibiting the NF-κB signaling activation in vitro. Moreover, we further explored the top 10 significantly changed mutants through zebrafish larvae infection model and validated that six genes were involved in inhibiting NF-κB activation in vivo. Specifically, we identified the adenylosuccinate synthase mutated strain (ΔpurA) infection exhibited a robust activation of NF-κB signaling, along with higher expression of cxcl8a and cxcl8b to mediate the recruitment of neutrophils in vivo. Taken together, these results identified the key factors of E. piscicida in inhibiting NF-κB activation, which will contribute to better understanding the pathogenesis of this important pathogen.
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Affiliation(s)
- Feizi Hu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Yuanxing Zhang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China; Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, 200237, China
| | - Qin Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China; Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, 200237, China
| | - Zhuang Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
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14
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Woida PJ, Satchell KJF. Bacterial Toxin and Effector Regulation of Intestinal Immune Signaling. Front Cell Dev Biol 2022; 10:837691. [PMID: 35252199 PMCID: PMC8888934 DOI: 10.3389/fcell.2022.837691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
The host immune response is highly effective to detect and clear infecting bacterial pathogens. Given the elaborate surveillance systems of the host, it is evident that in order to productively infect a host, the bacteria often coordinate virulence factors to fine-tune the host response during infection. These coordinated events can include either suppressing or activating the signaling pathways that control the immune response and thereby promote bacterial colonization and infection. This review will cover the surveillance and signaling systems for detection of bacteria in the intestine and a sample of the toxins and effectors that have been characterized that cirumvent these signaling pathways. These factors that promote infection and disease progression have also been redirected as tools or therapeutics. Thus, these toxins are enemies deployed to enhance infection, but can also be redeployed as allies to enable research and protect against infection.
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15
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Jiang L, Yang W, Jiang X, Yao T, Wang L, Yang B. Virulence-related O islands in enterohemorrhagic Escherichia coli O157:H7. Gut Microbes 2022; 13:1992237. [PMID: 34711138 PMCID: PMC8565820 DOI: 10.1080/19490976.2021.1992237] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a principally foodborne pathogen linked to serious diseases, including bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Comparative genomics analysis revealed that EHEC O157 contains 177 unique genomic islands, termed O islands, compared with the nonpathogenic E. coli K-12 laboratory strain. These O islands contribute largely to the pathogenicity of EHEC O157:H7 by providing numerous virulence factors, effectors, virulence regulatory proteins, and virulence regulatory sRNAs. The present review aimed to provide a comprehensive understanding of the research progress on the function of O islands, especially focusing on virulence-related O islands.
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Affiliation(s)
- Lingyan Jiang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, P. R. China
| | - Wen Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, P. R. China
| | - Xinlei Jiang
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin, P. R. China
| | - Ting Yao
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, P. R. China
| | - Lu Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, P. R. China
| | - Bin Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, P. R. China,CONTACT Bin Yang TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin300457, P. R. China
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16
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Abstract
The type III secretion system (T3SS) is crucial for the virulence of several pathogenic Escherichia coli species as well as for other gram-negative bacterial strains. Therefore, the ability to monitor this system constitutes a valuable tool for assessing the involvement of different proteins in bacterial virulence, for identifying critical domains and specific mutations, and for evaluating the antivirulence activities of various drugs. The major advantage of the T3SS secretion assay for E. coli over assays for other gram-negative pathogens is that it does not necessarily require specific antibodies. Here, we describe how to grow enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) strains under T3SS-inducing conditions, separate the supernatant fraction from the bacterial pellet, analyze this fraction on sodium dodecyl sulfate (SDS)-polyacrylamide gels, and evaluate the level of T3SS activity. We describe a qualitative analysis using Coomassie staining and a quantitative assay using western blotting.
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Affiliation(s)
- Bosko Mitrovic
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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17
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Tseytin I, Lezerovich S, David N, Sal-Man N. Interactions and substrate selectivity within the SctRST complex of the type III secretion system of enteropathogenic Escherichia coli. Gut Microbes 2022; 14:2013763. [PMID: 34965187 PMCID: PMC8726614 DOI: 10.1080/19490976.2021.2013763] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 02/04/2023] Open
Abstract
Many bacterial pathogens employ a protein complex, termed the type III secretion system (T3SS), to inject bacterial effectors into host cells. These effectors manipulate various cellular processes to promote bacterial growth and survival. The T3SS complex adopts a nano-syringe shape that is assembled across the bacterial membranes, with an extracellular needle extending toward the host cell membrane. The assembly of the T3SS is initiated by the association of three proteins, known as SctR, SctS, and SctT, which create an entry portal to the translocation channel within the bacterial inner membrane. Using the T3SS of enteropathogenic Escherichia coli, we investigated, by mutational and functional analyses, the role of two structural construction sites formed within the SctRST complex and revealed that they are mutation-resistant components that are likely to act as seals preventing leakage of ions and metabolites rather than as substrate gates. In addition, we identified two residues in the SctS protein, Pro23, and Lys54, that are critical for the proper activity of the T3SS. We propose that Pro23 is critical for the physical orientation of the SctS transmembrane domains that create the tip of the SctRST complex and for their positioning with regard to other T3SS substructures. Surprisingly, we found that SctS Lys54, which was previously suggested to mediate the SctS self-oligomerization, is critical for T3SS activity due to its essential role in SctS-SctT hetero-interactions.
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Affiliation(s)
- Irit Tseytin
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Shir Lezerovich
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Nofar David
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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18
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Leiser OP, Hobbs EC, Sims AC, Korch GW, Taylor KL. Beyond the List: Bioagent-Agnostic Signatures Could Enable a More Flexible and Resilient Biodefense Posture Than an Approach Based on Priority Agent Lists Alone. Pathogens 2021; 10:1497. [PMID: 34832652 PMCID: PMC8623450 DOI: 10.3390/pathogens10111497] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/11/2021] [Accepted: 11/13/2021] [Indexed: 12/23/2022] Open
Abstract
As of 2021, the biothreat policy and research communities organize their efforts around lists of priority agents, which elides consideration of novel pathogens and biotoxins. For example, the Select Agents and Toxins list is composed of agents that historic biological warfare programs had weaponized or that have previously caused great harm during natural outbreaks. Similarly, lists of priority agents promulgated by the World Health Organization and the National Institute of Allergy and Infectious Diseases are composed of previously known pathogens and biotoxins. To fill this gap, we argue that the research/scientific and biodefense/biosecurity communities should categorize agents based on how they impact their hosts to augment current list-based paradigms. Specifically, we propose integrating the results of multi-omics studies to identify bioagent-agnostic signatures (BASs) of disease-namely, patterns of biomarkers that accurately and reproducibly predict the impacts of infection or intoxication without prior knowledge of the causative agent. Here, we highlight three pathways that investigators might exploit as sources of signals to construct BASs and their applicability to this framework. The research community will need to forge robust interdisciplinary teams to surmount substantial experimental, technical, and data analytic challenges that stand in the way of our long-term vision. However, if successful, our functionality-based BAS model could present a means to more effectively surveil for and treat known and novel agents alike.
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Affiliation(s)
- Owen P. Leiser
- Pacific Northwest National Laboratory, Seattle, WA 98109, USA; (O.P.L.); (E.C.H.)
| | - Errett C. Hobbs
- Pacific Northwest National Laboratory, Seattle, WA 98109, USA; (O.P.L.); (E.C.H.)
| | - Amy C. Sims
- Pacific Northwest National Laboratory, Richland, WA 99354, USA;
| | - George W. Korch
- Battelle National Biodefense Institute, LLC, Fort Detrick, MD 21072, USA;
| | - Karen L. Taylor
- Pacific Northwest National Laboratory, Seattle, WA 98109, USA; (O.P.L.); (E.C.H.)
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19
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Categorizing sequences of concern by function to better assess mechanisms of microbial pathogenesis. Infect Immun 2021; 90:e0033421. [PMID: 34780277 PMCID: PMC9119117 DOI: 10.1128/iai.00334-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
To identify sequences with a role in microbial pathogenesis, we assessed the adequacy of their annotation by existing controlled vocabularies and sequence databases. Our goal was to regularize descriptions of microbial pathogenesis for improved integration with bioinformatic applications. Here, we review the challenges of annotating sequences for pathogenic activity. We relate the categorization of more than 2,750 sequences of pathogenic microbes through a controlled vocabulary called Functions of Sequences of Concern (FunSoCs). These allow for an ease of description by both humans and machines. We provide a subset of 220 fully annotated sequences in the supplemental material as examples. The use of this compact (∼30 terms), controlled vocabulary has potential benefits for research in microbial genomics, public health, biosecurity, biosurveillance, and the characterization of new and emerging pathogens.
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20
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The Roles of c-Jun N-Terminal Kinase (JNK) in Infectious Diseases. Int J Mol Sci 2021; 22:ijms22179640. [PMID: 34502556 PMCID: PMC8431791 DOI: 10.3390/ijms22179640] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/03/2021] [Accepted: 09/03/2021] [Indexed: 01/12/2023] Open
Abstract
c-Jun N-terminal kinases (JNKs) are among the most crucial mitogen-activated protein kinases (MAPKs) and regulate various cellular processes, including cell proliferation, apoptosis, autophagy, and inflammation. Microbes heavily rely on cellular signaling pathways for their effective replication; hence, JNKs may play important roles in infectious diseases. In this review, we describe the basic signaling properties of MAPKs and JNKs in apoptosis, autophagy, and inflammasome activation. Furthermore, we discuss the roles of JNKs in various infectious diseases induced by viruses, bacteria, fungi, and parasites, as well as their potential to serve as targets for the development of therapeutic agents for infectious diseases. We expect this review to expand our understanding of the JNK signaling pathway’s role in infectious diseases and provide important clues for the prevention and treatment of infectious diseases.
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21
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Chatterjee S, Lekmeechai S, Constantinou N, Grzybowska EA, Kozik Z, Choudhary JS, Berger CN, Frankel G, Clements A. The type III secretion system effector EspO of enterohaemorrhagic Escherichia coli inhibits apoptosis through an interaction with HAX-1. Cell Microbiol 2021; 23:e13366. [PMID: 34021690 PMCID: PMC7613270 DOI: 10.1111/cmi.13366] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 12/15/2022]
Abstract
Many enteric pathogens employ a type III secretion system (T3SS) to translocate effector proteins directly into the host cell cytoplasm, where they subvert signalling pathways of the intestinal epithelium. Here, we report that the anti-apoptotic regulator HS1-associated protein X1 (HAX-1) is an interaction partner of the T3SS effectors EspO of enterohaemorrhagic Escherichia coli (EHEC) and Citrobacter rodentium, OspE of Shigella flexneri and Osp1STYM of Salmonella enterica serovar Typhimurium. EspO, OspE and Osp1STYM have previously been reported to interact with the focal adhesions protein integrin linked kinase (ILK). We found that EspO localizes both to the focal adhesions (ILK localisation) and mitochondria (HAX-1 localisation), and that increased expression of HAX-1 leads to enhanced mitochondrial localisation of EspO. Ectopic expression of EspO, OspE and Osp1STYM protects cells from apoptosis induced by staurosporine and tunicamycin. Depleting cells of HAX-1 indicates that the anti-apoptotic activity of EspO is HAX-1 dependent. Both HAX-1 and ILK were further confirmed as EspO1-interacting proteins during infection using T3SS-delivered EspO1. Using cell detachment as a proxy for cell death we confirmed that T3SS-delivered EspO1 could inhibit cell death induced during EPEC infection, to a similar extent as the anti-apoptotic effector NleH, or treatment with the pan caspase inhibitor z-VAD. In contrast, in cells lacking HAX-1, EspO1 was no longer able to protect against cell detachment, while NleH1 and z-VAD maintained their protective activity. Therefore, during both infection and ectopic expression EspO protects cells from cell death by interacting with HAX-1. These results suggest that despite the differences between EHEC, C. rodentium, Shigella and S. typhimurium infections, hijacking HAX-1 anti-apoptotic signalling is a common strategy to maintain the viability of infected cells. TAKE AWAY: EspO homologues are found in EHEC, Shigella, S. typhimurium and some EPEC. EspO homologues interact with HAX-1. EspO protects infected cells from apoptosis. EspO joins a growing list of T3SS effectors that manipulate cell death pathways.
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Affiliation(s)
- Sharanya Chatterjee
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College, London, UK
| | - Sujinna Lekmeechai
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College, London, UK
| | - Nicolas Constantinou
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College, London, UK
| | - Ewa A. Grzybowska
- Department of Molecular and Translational Oncology, Maria Sklodowska-Curie National Institute of Oncology, Warsaw, Poland
| | - Zuzanna Kozik
- Functional Proteomics Group, The Institute for Cancer Research, London, UK
| | - Jyoti S. Choudhary
- Functional Proteomics Group, The Institute for Cancer Research, London, UK
| | - Cedric N. Berger
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College, London, UK
| | - Gad Frankel
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College, London, UK
| | - Abigail Clements
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College, London, UK
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22
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Mitrović B, Lezerovich S, Sal-Man N. The Role of the Membrane-Associated Domain of the Export Apparatus Protein, EscV (SctV), in the Activity of the Type III Secretion System. Front Microbiol 2021; 12:719469. [PMID: 34413845 PMCID: PMC8369761 DOI: 10.3389/fmicb.2021.719469] [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: 06/02/2021] [Accepted: 07/05/2021] [Indexed: 11/13/2022] Open
Abstract
Diarrheal diseases remain a major public health concern worldwide. Many of the causative bacterial pathogens that cause these diseases have a specialized protein complex, the type III secretion system (T3SS), which delivers effector proteins directly into host cells. These effectors manipulate host cell processes for the benefit of the infecting bacteria. The T3SS structure resembles a syringe anchored within the bacterial membrane, projecting toward the host cell membrane. The entry port of the T3SS substrates, called the export apparatus, is formed by five integral membrane proteins. Among the export apparatus proteins, EscV is the largest, and as it forms a nonamer, it constitutes the largest portion of the export apparatus complex. While there are considerable data on the soluble cytoplasmic domain of EscV, our knowledge of its membrane-associated section and its transmembrane domains (TMDs) is still very limited. In this study, using an isolated genetic reporter system, we found that TMD5 and TMD6 of EscV mediate strong self-oligomerization. Substituting these TMDs within the full-length protein with a random hydrophobic sequence resulted in a complete loss of function of the T3SS, further suggesting that the EscV TMD5 and TMD6 sequences have a functional role in addition to their structural role as membrane anchors. As we observed only mild reduction in the ability of the TMD-exchanged variants to integrate into the full or intermediate T3SS complexes, we concluded that EscV TMD5 and TMD6 are not crucial for the global assembly or stability of the T3SS complex but are rather involved in promoting the necessary TMD–TMD interactions within the complex and the overall TMD orientation to allow channel opening for the entry of T3SS substrates.
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Affiliation(s)
- Boško Mitrović
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Shir Lezerovich
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
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23
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Viana F, Peringathara SS, Rizvi A, Schroeder GN. Host manipulation by bacterial type III and type IV secretion system effector proteases. Cell Microbiol 2021; 23:e13384. [PMID: 34392594 DOI: 10.1111/cmi.13384] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 01/08/2023]
Abstract
Proteases are powerful enzymes, which cleave peptide bonds, leading most of the time to irreversible fragmentation or degradation of their substrates. Therefore they control many critical cell fate decisions in eukaryotes. Bacterial pathogens exploit this power and deliver protease effectors through specialised secretion systems into host cells. Research over the past years revealed that the functions of protease effectors during infection are diverse, reflecting the lifestyles and adaptations to specific hosts; however, only a small number of peptidase families seem to have given rise to most of these protease virulence factors by the evolution of different substrate-binding specificities, intracellular activation and subcellular targeting mechanisms. Here, we review our current knowledge about the enzymology and function of protease effectors, which Gram-negative bacterial pathogens translocate via type III and IV secretion systems to irreversibly manipulate host processes. We highlight emerging concepts such as signalling by protease cleavage products and effector-triggered immunity, which host cells employ to detect and defend themselves against a protease attack. TAKE AWAY: Proteases irreversibly cleave proteins to control critical cell fate decisions. Gram-negative bacteria use type III and IV secretion systems to inject effectors. Protease effectors are integral weapons for the manipulation of host processes. Effectors evolved from few peptidase families to target diverse substrates. Effector-triggered immunity upon proteolytic attack emerges as host defence.
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Affiliation(s)
- Flávia Viana
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Shruthi Sachidanandan Peringathara
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Arshad Rizvi
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Gunnar N Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
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24
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Chen RY, Keddie BA. The Galleria mellonella-Enteropathogenic Escherichia coli Model System: Characterization of Pathogen Virulence and Insect Immune Responses. JOURNAL OF INSECT SCIENCE (ONLINE) 2021; 21:6329131. [PMID: 34314494 PMCID: PMC8315237 DOI: 10.1093/jisesa/ieab046] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Indexed: 05/22/2023]
Abstract
The use of Galleria mellonella (Linnaeus) (Lepidoptera: Pyralidae), an economical insect model, for the study of enteropathogenic Escherichia coli (Migula) (EPEC), a diarrheagenic human pathogen, has been demonstrated previously but remains poorly understood. The present study characterizes the Galleria-EPEC system extensively for future studies using this system. We found that EPEC causes disease in G. mellonella larvae when injected intrahemocoelically but not orally. Disease manifests as increased mortality, decreased survival time, delayed pupation, decreased pupal mass, increased pupal duration, and hemocytopenia. Disease symptoms are dose-dependent and can be used as metrics for measuring EPEC virulence in future studies. The type III secretion system was only partially responsible for EPEC virulence in G. mellonella while the majority of the virulence remains unknown in origin. EPEC elicits insect anti-bacterial immune responses including melanization, hemolymph coagulation, nodulation, and phagocytosis. The immune responses were unable to control EPEC replication in the early stage of infection (≤3 h post-injection). EPEC clearance from the hemocoel does not guarantee insect survival. Overall, this study provided insights into EPEC virulence and pathogenesis in G. mellonella and identified areas of future research using this system.
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Affiliation(s)
- Robin Y Chen
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
- Corresponding author, e-mail:
| | - B Andrew Keddie
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
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Hajra D, Nair AV, Chakravortty D. An elegant nano-injection machinery for sabotaging the host: Role of Type III secretion system in virulence of different human and animal pathogenic bacteria. Phys Life Rev 2021; 38:25-54. [PMID: 34090822 DOI: 10.1016/j.plrev.2021.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 05/23/2021] [Indexed: 01/22/2023]
Abstract
Various Gram-negative bacteria possess a specialized membrane-bound protein secretion system known as the Type III secretion system (T3SS), which transports the bacterial effector proteins into the host cytosol thereby helping in bacterial pathogenesis. The T3SS has a special needle-like translocon that can sense the contact with the host cell membrane and translocate effectors. The export apparatus of T3SS recognizes these effector proteins bound to chaperones and translocates them into the host cell. Once in the host cell cytoplasm, these effector proteins result in modulation of the host system and promote bacterial localization and infection. Using molecular biology, bioinformatics, genetic techniques, electron microscopic studies, and mathematical modeling, the structure and function of the T3SS and the corresponding effector proteins in various bacteria have been studied. The strategies used by different human pathogenic bacteria to modulate the host system and thereby enhance their virulence mechanism using T3SS have also been well studied. Here we review the history, evolution, and general structure of the T3SS, highlighting the details of its comparison with the flagellar export machinery. Also, this article provides mechanistic details about the common role of T3SS in subversion and manipulation of host cellular processes. Additionally, this review describes specific T3SS apparatus and the role of their specific effectors in bacterial pathogenesis by considering several human and animal pathogenic bacteria.
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Affiliation(s)
- Dipasree Hajra
- Department of Microbiology & Cell Biology, Indian Institute of Science, India
| | - Abhilash Vijay Nair
- Department of Microbiology & Cell Biology, Indian Institute of Science, India
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26
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Hasan MK, El Qaidi S, Hardwidge PR. The T3SS Effector Protease NleC Is Active within Citrobacter rodentium. Pathogens 2021; 10:pathogens10050589. [PMID: 34065796 PMCID: PMC8151275 DOI: 10.3390/pathogens10050589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 11/18/2022] Open
Abstract
Whether type III secretion system (T3SS) effector proteins encoded by Gram-negative bacterial pathogens have intra-bacterial activities is an important and emerging area of investigation. Gram-negative bacteria interact with their mammalian hosts by using secretion systems to inject virulence proteins directly into infected host cells. Many of these injected protein effectors are enzymes that modify the structure and inhibit the function of mammalian proteins. The underlying dogma is that T3SS effectors are inactive until they are injected into host cells, where they then fold into their active conformations. We previously observed that the T3SS effectors NleB and SseK1 glycosylate Citrobacter rodentium and Salmonella enterica proteins, respectively, leading to enhanced resistance to environmental stress. Here, we sought to extend these studies to determine whether the T3SS effector protease NleC is also active within C. rodentium. To do this, we expressed the best-characterized mammalian substrate of NleC, the NF-κB p65 subunit in C. rodentium and monitored its proteolytic cleavage as a function of NleC activity. Intra-bacterial p65 cleavage was strictly dependent upon NleC. A p65 mutant lacking the known CE cleavage motif was resistant to NleC. Thus, we conclude that, in addition to NleB, NleC is also enzymatically active within C. rodentium.
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27
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Nissim-Eliraz E, Nir E, Marsiano N, Yagel S, Shpigel NY. NF-kappa-B activation unveils the presence of inflammatory hotspots in human gut xenografts. PLoS One 2021; 16:e0243010. [PMID: 33939711 PMCID: PMC8092666 DOI: 10.1371/journal.pone.0243010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/17/2021] [Indexed: 12/13/2022] Open
Abstract
The single-epithelial cell layer of the gut mucosa serves as an essential barrier between the host and luminal microflora and plays a major role in innate immunity against invading pathogens. Nuclear factor kB (NF-κB), a central component of the cellular signaling machinery, regulates immune response and inflammation. NF-κB proteins are activated by signaling pathways downstream to microbial recognition receptors and cytokines receptors. Highly regulated NF-κB activity in intestinal epithelial cells (IEC) is essential for normal gut homeostasis; dysregulated activity has been linked to a number of disease states, including inflammatory bowel diseases (IBD) such as Crohn's Disease (CD). Our aim was to visualize and quantify spatial and temporal dynamics of NF-κB activity in steady state and inflamed human gut. Lentivirus technology was used to transduce the IEC of human gut xenografts in SCID mice with a NF-κB luminescence reporter system. NF-κB signaling was visualized and quantified using low resolution, intravital imaging of the whole body and high resolution, immunofluorescence microscopic imaging of the tissues. We show that NF-κB is activated in select subset of IEC with low "leaky" NF-κB activity. These unique inflammatory epithelial cells are clustered in the gut into discrete hotspots of NF-κB activity that are visible in steady state and selectively activated by systemic LPS and human TNFα or luminal bacteria. The presence of inflammatory hotspots in the normal and inflamed gut might explain the patchy mucosal lesions characterizing CD and thus could have important implications for diagnosis and therapy.
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Affiliation(s)
- Einat Nissim-Eliraz
- Department of Basic Sciences, Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - Eilam Nir
- Department of Basic Sciences, Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - Noga Marsiano
- Department of Basic Sciences, Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - Simcha Yagel
- Department of Obstetrics and Gynecology, Hadassah University Hospital, Jerusalem, Israel
| | - Nahum Y. Shpigel
- Department of Basic Sciences, Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
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28
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Mooney BC, Mantz M, Graciet E, Huesgen PF. Cutting the line: manipulation of plant immunity by bacterial type III effector proteases. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3395-3409. [PMID: 33640987 DOI: 10.1093/jxb/erab095] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
Pathogens and their hosts are engaged in an evolutionary arms race. Pathogen-derived effectors promote virulence by targeting components of a host's innate immune system, while hosts have evolved proteins that sense effectors and trigger a pathogen-specific immune response. Many bacterial effectors are translocated into host cells using type III secretion systems. Type III effector proteases irreversibly modify host proteins by cleavage of peptide bonds and are prevalent among both plant and animal bacterial pathogens. In plants, the study of model effector proteases has yielded important insights into the virulence mechanisms employed by pathogens to overcome their host's immune response, as well as into the mechanisms deployed by their hosts to detect these effector proteases and counteract their effects. In recent years, the study of a larger number of effector proteases, across a wider range of pathogens, has yielded novel insights into their functions and recognition. One key limitation that remains is the lack of methods to detect protease cleavage at the proteome-wide level. We review known substrates and mechanisms of plant pathogen type III effector proteases and compare their functions with those of known type III effector proteases of mammalian pathogens. Finally, we discuss approaches to uncover their function on a system-wide level.
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Affiliation(s)
- Brian C Mooney
- Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Melissa Mantz
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany
- CECAD, Medical Faculty and University Hospital, University of Cologne, Cologne, Germany
| | - Emmanuelle Graciet
- Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Pitter F Huesgen
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany
- CECAD, Medical Faculty and University Hospital, University of Cologne, Cologne, Germany
- Institute for Biochemistry, Faculty of Mathematics and Natural Sciences, University of Cologne, Cologne, Germany
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Takemura M, Haneda T, Idei H, Miki T, Okada N. A Salmonella type III effector, PipA, works in a different manner than the PipA family effectors GogA and GtgA. PLoS One 2021; 16:e0248975. [PMID: 33735297 PMCID: PMC7971870 DOI: 10.1371/journal.pone.0248975] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/08/2021] [Indexed: 12/31/2022] Open
Abstract
Nuclear factor-kappa B (NF-κB) plays a critical role in the host defense against microbial pathogens. Many pathogens modulate NF-κB signaling to establish infection in their host. Salmonella enterica serovar Typhimurium (S. Typhimurium) possesses two type III secretion systems (T3SS-1 and T3SS-2) and directly injects many effector proteins into host cells. It has been reported that some effectors block NF-κB signaling, but the molecular mechanism of the inactivation of NF-κB signaling in S. Typhimurium is poorly understood. Here, we identified seven type III effectors-GogA, GtgA, PipA, SseK1, SseK2, SseK3, and SteE-that inhibited NF-κB activation in HeLa cells stimulated with TNF-α. We also determined that only GogA and GtgA are involved in regulation of the activation of NF-κB in HeLa cells infected with S. Typhimurium. GogA, GtgA, and PipA are highly homologous to one another and have the consensus zinc metalloprotease HEXXH motif. Our experiments demonstrated that GogA, GtgA, and PipA each directly cleaved NF-κB p65, whereas GogA and GtgA, but not PipA, inhibited the NF-κB activation in HeLa cells infected with S. Typhimurium. Further, expressions of the gogA or gtgA gene were induced under the SPI-1-and SPI-2-inducing conditions, but expression of the pipA gene was induced only under the SPI-2-inducing condition. We also showed that PipA was secreted into RAW264.7 cells through T3SS-2. Finally, we indicated that PipA elicits bacterial dissemination in the systemic stage of infection of S. Typhimurium via a T3SS-1-independent mechanism. Collectively, our results suggest that PipA, GogA and GtgA contribute to S. Typhimurium pathogenesis in different ways.
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Affiliation(s)
- Momo Takemura
- Laboratory of Microbiology, School of Pharmacy, Kitasato University, Minato, Tokyo, Japan
| | - Takeshi Haneda
- Laboratory of Microbiology, School of Pharmacy, Kitasato University, Minato, Tokyo, Japan
- * E-mail:
| | - Hikari Idei
- Laboratory of Microbiology, School of Pharmacy, Kitasato University, Minato, Tokyo, Japan
| | - Tsuyoshi Miki
- Laboratory of Microbiology, School of Pharmacy, Kitasato University, Minato, Tokyo, Japan
| | - Nobuhiko Okada
- Laboratory of Microbiology, School of Pharmacy, Kitasato University, Minato, Tokyo, Japan
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Gershberg J, Braverman D, Sal-Man N. Transmembrane domains of type III-secreted proteins affect bacterial-host interactions in enteropathogenic E. coli. Virulence 2021; 12:902-917. [PMID: 33729090 PMCID: PMC7993127 DOI: 10.1080/21505594.2021.1898777] [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] [Indexed: 11/21/2022] Open
Abstract
Many bacterial pathogens utilize a specialized secretion system, termed type III secretion system (T3SS), to translocate effector proteins into host cells and establish bacterial infection. The T3SS is anchored within the bacterial membranes and contains a long needle/filament that extends toward the host-cell and forms, at its distal end, a pore complex within the host membrane. The T3SS pore complex consists of two bacterial proteins, termed SctB and SctE, which have conflicting targeting indications; a signal sequence that targets to secretion to the extracellular environment via the T3SS, and transmembrane domains (TMDs) that target to membrane localization. In this study, we investigate whether the TMD sequences of SctB and SctE have special features that differentiate them from classical TMDs and allow them to escape bacterial membrane integration. For this purpose, we exchanged the SctB and SctE native TMDs for alternative hydrophobic sequences and found that the TMD sequences of SctB and SctE dictate membrane destination (bacterial versus host membrane). Moreover, we examined the role of the SctB TMD sequence in the activity of the full-length protein, post secretion, and found that the TMD does not serve only as a hydrophobic segment, but is also involved in the ability of the protein to translocate itself and other proteins into and across the host cell membrane.
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Affiliation(s)
- Jenia Gershberg
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Dor Braverman
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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31
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Ruano-Gallego D, Sanchez-Garrido J, Kozik Z, Núñez-Berrueco E, Cepeda-Molero M, Mullineaux-Sanders C, Naemi Baghshomali Y, Slater SL, Wagner N, Glegola-Madejska I, Roumeliotis TI, Pupko T, Fernández LÁ, Rodríguez-Patón A, Choudhary JS, Frankel G. Type III secretion system effectors form robust and flexible intracellular virulence networks. Science 2021; 371:eabc9531. [PMID: 33707240 DOI: 10.1126/science.abc9531] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 12/15/2020] [Accepted: 01/15/2021] [Indexed: 12/14/2022]
Abstract
Infections with many Gram-negative pathogens, including Escherichia coli, Salmonella, Shigella, and Yersinia, rely on type III secretion system (T3SS) effectors. We hypothesized that while hijacking processes within mammalian cells, the effectors operate as a robust network that can tolerate substantial contractions. This was tested in vivo using the mouse pathogen Citrobacter rodentium (encoding 31 effectors). Sequential gene deletions showed that effector essentiality for infection was context dependent and that the network could tolerate 60% contraction while maintaining pathogenicity. Despite inducing very different colonic cytokine profiles (e.g., interleukin-22, interleukin-17, interferon-γ, or granulocyte-macrophage colony-stimulating factor), different networks induced protective immunity. Using data from >100 distinct mutant combinations, we built and trained a machine learning model able to predict colonization outcomes, which were confirmed experimentally. Furthermore, reproducing the human-restricted enteropathogenic E. coli effector repertoire in C. rodentium was not sufficient for efficient colonization, which implicates effector networks in host adaptation. These results unveil the extreme robustness of both T3SS effector networks and host responses.
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Affiliation(s)
- David Ruano-Gallego
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Julia Sanchez-Garrido
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Zuzanna Kozik
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, UK
| | - Elena Núñez-Berrueco
- Laboratorio de Inteligencia Artificial, Departamento de Inteligencia Artificial, Universidad Politécnica de Madrid, Campus de Montegancedo, Boadilla del Monte, Madrid, Spain
| | - Massiel Cepeda-Molero
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | | | - Yasaman Naemi Baghshomali
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Sabrina L Slater
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Izabela Glegola-Madejska
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Theodoros I Roumeliotis
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, UK
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Luis Ángel Fernández
- Centro Nacional de Biotecnología (CNB-CSIC), Department of Microbial Biotechnology, Madrid, Spain
| | - Alfonso Rodríguez-Patón
- Laboratorio de Inteligencia Artificial, Departamento de Inteligencia Artificial, Universidad Politécnica de Madrid, Campus de Montegancedo, Boadilla del Monte, Madrid, Spain
| | - Jyoti S Choudhary
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, UK.
| | - Gad Frankel
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College, London, UK.
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Mak H, Thurston TLM. Interesting Biochemistries in the Structure and Function of Bacterial Effectors. Front Cell Infect Microbiol 2021; 11:608860. [PMID: 33718265 PMCID: PMC7943720 DOI: 10.3389/fcimb.2021.608860] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 01/13/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial effector proteins, delivered into host cells by specialized multiprotein secretion systems, are a key mediator of bacterial pathogenesis. Following delivery, they modulate a range of host cellular processes and functions. Strong selective pressures have resulted in bacterial effectors evolving unique structures that can mimic host protein biochemical activity or enable novel and distinct biochemistries. Despite the protein structure-function paradigm, effectors from different bacterial species that share biochemical activities, such as the conjugation of ubiquitin to a substrate, do not necessarily share structural or sequence homology to each other or the eukaryotic proteins that carry out the same function. Furthermore, some bacterial effectors have evolved structural variations to known protein folds which enable different or additional biochemical and physiological functions. Despite the overall low occurrence of intrinsically disordered proteins or regions in prokaryotic proteomes compared to eukaryotes proteomes, bacterial effectors appear to have adopted intrinsically disordered regions that mimic the disordered regions of eukaryotic signaling proteins. In this review, we explore examples of the diverse biochemical properties found in bacterial effectors that enable effector-mediated interference of eukaryotic signaling pathways and ultimately support pathogenesis. Despite challenges in the structural and functional characterisation of effectors, recent progress has been made in understanding the often unusual and fascinating ways in which these virulence factors promote pathogenesis. Nevertheless, continued work is essential to reveal the array of remarkable activities displayed by effectors.
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Affiliation(s)
| | - Teresa L. M. Thurston
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
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33
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Citrobacter rodentium Infection Induces Persistent Molecular Changes and Interferon Gamma-Dependent Major Histocompatibility Complex Class II Expression in the Colonic Epithelium. mBio 2021; 13:e0323321. [PMID: 35100877 PMCID: PMC8805023 DOI: 10.1128/mbio.03233-21] [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] [Indexed: 12/28/2022] Open
Abstract
Most studies of infections at mucosal surfaces have focused on the acute phase of the disease. Consequently, little is known about the molecular processes that underpin tissue recovery and the long-term consequences postinfection. Here, we conducted temporal deep quantitative proteomic analysis of colonic intestinal epithelial cells (cIECs) from mice infected with the natural mouse pathogen Citrobacter rodentium over time points corresponding to the late steady-state phase (10 days postinfection [DPI]), the clearance phase (13 to 20 DPI), and 4 weeks after the pathogen has been cleared (48 DPI). C. rodentium, which relies on a type III secretion system to infect, is used to model infections with enteropathogenic and enterohemorrhagic Escherichia coli. We observe a strong upregulation of inflammatory signaling and nutritional immunity responses during the clearance phase of the infection. Despite morphological tissue recovery, chromogranin B (ChgB)-positive endocrine cells remained significantly below baseline levels at 48 DPI. In contrast, we observed an increased abundance of proteins involved in antigen processing and presentation 4 weeks after pathogen clearance. In particular, long-term changes were characterized by a persistent interferon gamma (IFN-γ) response and the expression of major histocompatibility complex class II (MHCII) molecules in 60% of the EpCAM+ cIECs, which were not seen in Ifnγ-/- mice. Nonetheless, both wild-type and Ifnγ-/- mice mounted similar systemic and colonic IgG responses to C. rodentium and were equally protected from rechallenge, suggesting that cIEC MHCII is not necessary for protective immunity against C. rodentium. IMPORTANCE Mucosal surfaces respond to infection by mounting an array of metabolic, inflammatory, and tissue repair responses. While these have been well studied during acute infection, less is known about tissue recovery after pathogen clearance. We employ the mouse pathogen Citrobacter rodentium, which binds colonic intestinal epithelial cells (cIECs), to investigate the long-term effects of bacterial infection on gut physiology. Using global proteomic analysis, we study cIEC temporal responses during and after the clearance phase of infection. While the overall tissue morphology recovered, cIECs showed persistent signs of infection 4 weeks after pathogen clearance. These were characterized by a strong IFN-γ signature, including the upregulation of major histocompatibility complex class II (MHCII) antigen presentation proteins, suggesting that the tissue remains on "high alert" for weeks after the acute insult is resolved. However, we demonstrate that cIEC MHCII expression, which is induced by IFN-γ, is not required for protective IgG-mediated immunity against C. rodentium; instead, it may play a role in mucosal recovery.
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34
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Huang A, Lu M, Ling E, Li P, Wang C. A M35 family metalloprotease is required for fungal virulence against insects by inactivating host prophenoloxidases and beyond. Virulence 2021; 11:222-237. [PMID: 32079481 PMCID: PMC7051145 DOI: 10.1080/21505594.2020.1731126] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
A diverse family of metalloproteases (MPs) is distributed in eukaryotes. However, the functions of MPs are still understudied. We report that seven MPs belonging to the M35 family are encoded in the genome of the insect pathogenic fungus Metarhizium robertsii. By gene deletions and insect bioassays, we found that one of the M35-family MPs, i.e. MrM35-4, is required for fungal virulence against insect hosts. MrM35-4 is a secretable enzyme and shows a proteolytic activity implicated in facilitating fungal penetration of insect cuticles. After gene rescue and overexpression, insect bioassays indicated that MrM35-4 contributes to inhibiting insect cuticular and hemocyte melanization activities. Enzymatic cleavage assays revealed that the recombinant prophenoloxidases PPO1 and PPO2 of Drosophila melanogaster could be clipped by MrM35-4 in a manner differing from a serine protease that can activate PPO activities. In addition, it was found that MrM35-4 is involved in suppressing antifungal gene expression in insects. Consistent with the evident apoptogenic effect of MrM35-4 on host cells, we found that the PPO mutant flies differentially succumbed to the infections of the wild-type and mutant strains of M. robertsii. Thus, MrM35-4 plays a multifaceted role beyond targeting PPOs during fungus-insect interactions, which represents a previously unsuspected strategy employed by Metarhizium to outmaneuver insect immune defenses.
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Affiliation(s)
- Antian Huang
- School of Life Science and Technology, Tongji University, Shanghai, China.,CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Mengting Lu
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Erjun Ling
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Ping Li
- School of Life Science and Technology, Tongji University, Shanghai, China
| | - Chengshu Wang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
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35
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Hillman Y, Gershberg J, Lustiger D, Even D, Braverman D, Dror Y, Ashur I, Vernick S, Sal-Man N, Wine Y. Monoclonal Antibody-Based Biosensor for Point-of-Care Detection of Type III Secretion System Expressing Pathogens. Anal Chem 2020; 93:928-935. [DOI: 10.1021/acs.analchem.0c03621] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Yaron Hillman
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Green building, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Jenia Gershberg
- Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 8410501, Israel
| | - Dan Lustiger
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Green building, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Dan Even
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Green building, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Dor Braverman
- Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 8410501, Israel
| | - Yael Dror
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Green building, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Idan Ashur
- Institute of Agricultural Engineering, Agricultural Research Organization, Volcani Center, 68 Hamaccabim Rd, Rishon Lezion 5025001, Israel
| | - Sefi Vernick
- Institute of Agricultural Engineering, Agricultural Research Organization, Volcani Center, 68 Hamaccabim Rd, Rishon Lezion 5025001, Israel
| | - Neta Sal-Man
- Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 8410501, Israel
| | - Yariv Wine
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Green building, Tel-Aviv University, Tel Aviv 6997801, Israel
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36
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Zhong Q, Roumeliotis TI, Kozik Z, Cepeda-Molero M, Fernández LÁ, Shenoy AR, Bakal C, Frankel G, Choudhary JS. Clustering of Tir during enteropathogenic E. coli infection triggers calcium influx-dependent pyroptosis in intestinal epithelial cells. PLoS Biol 2020; 18:e3000986. [PMID: 33378358 PMCID: PMC7773185 DOI: 10.1371/journal.pbio.3000986] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 11/24/2020] [Indexed: 11/19/2022] Open
Abstract
Clustering of the enteropathogenic Escherichia coli (EPEC) type III secretion system (T3SS) effector translocated intimin receptor (Tir) by intimin leads to actin polymerisation and pyroptotic cell death in macrophages. The effect of Tir clustering on the viability of EPEC-infected intestinal epithelial cells (IECs) is unknown. We show that EPEC induces pyroptosis in IECs in a Tir-dependent but actin polymerisation-independent manner, which was enhanced by priming with interferon gamma (IFNγ). Mechanistically, Tir clustering triggers rapid Ca2+ influx, which induces lipopolysaccharide (LPS) internalisation, followed by activation of caspase-4 and pyroptosis. Knockdown of caspase-4 or gasdermin D (GSDMD), translocation of NleF, which blocks caspase-4 or chelation of extracellular Ca2+, inhibited EPEC-induced cell death. IEC lines with low endogenous abundance of GSDMD were resistant to Tir-induced cell death. Conversely, ATP-induced extracellular Ca2+ influx enhanced cell death, which confirmed the key regulatory role of Ca2+ in EPEC-induced pyroptosis. We reveal a novel mechanism through which infection with an extracellular pathogen leads to pyroptosis in IECs.
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Affiliation(s)
- Qiyun Zhong
- Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, United Kingdom
| | - Theodoros I. Roumeliotis
- Functional Proteomics Group, Chester Beatty Laboratories, The Institute of Cancer Research, London, United Kingdom
| | - Zuza Kozik
- Functional Proteomics Group, Chester Beatty Laboratories, The Institute of Cancer Research, London, United Kingdom
| | - Massiel Cepeda-Molero
- Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, United Kingdom
| | - Luis Ángel Fernández
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Campus UAM-Cantoblanco, Madrid, Spain
| | - Avinash R. Shenoy
- Centre for Molecular Bacteriology & Infection, Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Chris Bakal
- Dynamical Cell Systems, Chester Beatty Laboratories, The Institute of Cancer Research, London, United Kingdom
| | - Gad Frankel
- Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, United Kingdom
| | - Jyoti S. Choudhary
- Functional Proteomics Group, Chester Beatty Laboratories, The Institute of Cancer Research, London, United Kingdom
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Gan J, Giogha C, Hartland EL. Molecular mechanisms employed by enteric bacterial pathogens to antagonise host innate immunity. Curr Opin Microbiol 2020; 59:58-64. [PMID: 32862049 DOI: 10.1016/j.mib.2020.07.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 07/25/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022]
Abstract
Many Gram-negative enteric pathogens, including enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC), Salmonella, Shigella, and Yersinia species have evolved strategies to combat host defence mechanisms. Critical bacterial virulence factors, which often include but are not limited to type III secreted effector proteins, are deployed to cooperatively interfere with key host defence pathways. Recent studies in this area have not only contributed to our knowledge of bacterial pathogenesis, but have also shed light on the host pathways that are critical for controlling bacterial infection. In this review, we summarise recent breakthroughs in our understanding of the mechanisms utilised by enteric bacterial pathogens to rewire critical host innate immune responses, including cell death and inflammatory signaling and cell-intrinsic anti-microbial responses such as xenophagy.
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Affiliation(s)
- Jiyao Gan
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Victoria, Australia; Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Cristina Giogha
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia; Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia
| | - Elizabeth L Hartland
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia; Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia.
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38
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Riebisch AK, Mühlen S. Attaching and effacing pathogens: the effector ABC of immune subversion. Future Microbiol 2020; 15:945-958. [PMID: 32716209 DOI: 10.2217/fmb-2019-0274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The innate immune response resembles an essential barrier to bacterial infection. Many bacterial pathogens have, therefore, evolved mechanisms to evade from or subvert the host immune response in order to colonize, survive and multiply. The attaching and effacing pathogens enteropathogenic Escherichia coli, enterohaemorrhagic E. coli, Escherichia albertii and Citrobacter rodentium are Gram-negative extracellular gastrointestinal pathogens. They use a type III secretion system to inject effector proteins into the host cell to manipulate a variety of cellular processes. Over the last decade, considerable progress was made in identifying and characterizing the effector proteins of attaching and effacing pathogens that are involved in the inhibition of innate immune signaling pathways, in determining their host cell targets and elucidating the mechanisms they employ. Their functions will be reviewed here.
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Affiliation(s)
- Anna Katharina Riebisch
- Systems-Oriented Immunology & Inflammation Research, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.,Institute for Molecular & Clinical Immunology, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany.,Department of Molecular Immunology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Sabrina Mühlen
- Institute for Infectiology, University of Münster, 48149 Münster, Germany.,German Center for Infection Research (DZIF), Associated Site University of Münster, 48149 Münster, Germany
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39
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Denzer L, Schroten H, Schwerk C. From Gene to Protein-How Bacterial Virulence Factors Manipulate Host Gene Expression During Infection. Int J Mol Sci 2020; 21:ijms21103730. [PMID: 32466312 PMCID: PMC7279228 DOI: 10.3390/ijms21103730] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 02/06/2023] Open
Abstract
Bacteria evolved many strategies to survive and persist within host cells. Secretion of bacterial effectors enables bacteria not only to enter the host cell but also to manipulate host gene expression to circumvent clearance by the host immune response. Some effectors were also shown to evade the nucleus to manipulate epigenetic processes as well as transcription and mRNA procession and are therefore classified as nucleomodulins. Others were shown to interfere downstream with gene expression at the level of mRNA stability, favoring either mRNA stabilization or mRNA degradation, translation or protein stability, including mechanisms of protein activation and degradation. Finally, manipulation of innate immune signaling and nutrient supply creates a replicative niche that enables bacterial intracellular persistence and survival. In this review, we want to highlight the divergent strategies applied by intracellular bacteria to evade host immune responses through subversion of host gene expression via bacterial effectors. Since these virulence proteins mimic host cell enzymes or own novel enzymatic functions, characterizing their properties could help to understand the complex interactions between host and pathogen during infections. Additionally, these insights could propose potential targets for medical therapy.
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Gur-Arie L, Eitan-Wexler M, Weinberger N, Rosenshine I, Livnah O. The bacterial metalloprotease NleD selectively cleaves mitogen-activated protein kinases that have high flexibility in their activation loop. J Biol Chem 2020; 295:9409-9420. [PMID: 32404367 DOI: 10.1074/jbc.ra120.013590] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/07/2020] [Indexed: 01/07/2023] Open
Abstract
Microbial pathogens often target the host mitogen-activated protein kinase (MAPK) network to suppress host immune responses. We previously identified a bacterial type III secretion system effector, termed NleD, a metalloprotease that inactivates MAPKs by specifically cleaving their activation loop. Here, we show that NleDs form a growing family of virulence factors harbored by human and plant pathogens as well as insect symbionts. These NleDs disable specifically Jun N-terminal kinases (JNKs) and p38s that are required for host immune response, whereas extracellular signal-regulated kinase (ERK), which is essential for host cell viability, remains intact. We investigated the mechanism that makes ERK resistant to NleD cleavage. Biochemical and structural analyses revealed that NleD exclusively targets activation loops with high conformational flexibility. Accordingly, NleD cleaved the flexible loops of JNK and p38 but not the rigid loop of ERK. Our findings elucidate a compelling mechanism of native substrate proteolysis that is promoted by entropy-driven specificity. We propose that such entropy-based selectivity is a general attribute of proteolytic enzymes.
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Affiliation(s)
- Lihi Gur-Arie
- Department Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maayan Eitan-Wexler
- Department of Biological Chemistry, Alexander Silverman Institute of Life Sciences, The Wolfson Centre for Applied Structural Biology, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nina Weinberger
- Department of Biological Chemistry, Alexander Silverman Institute of Life Sciences, The Wolfson Centre for Applied Structural Biology, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ilan Rosenshine
- Department Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Oded Livnah
- Department of Biological Chemistry, Alexander Silverman Institute of Life Sciences, The Wolfson Centre for Applied Structural Biology, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel
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Pan X, Luo J, Li S. Bacteria-Catalyzed Arginine Glycosylation in Pathogens and Host. Front Cell Infect Microbiol 2020; 10:185. [PMID: 32411621 PMCID: PMC7199390 DOI: 10.3389/fcimb.2020.00185] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/07/2020] [Indexed: 01/25/2023] Open
Abstract
In recent years, protein glycosylation in pathogenic bacteria has attracted more and more attention, and accumulating evidence indicated that this type of posttranslational modification is involved in many physiological processes. The NleB from several enteropathogenic bacteria species as well as SseK from Salmonella enterica are type III secretion system effectors, which have an atypical N-acetylglucosamine (N-GlcNAc) transferase activity that specifically modified a conserved arginine in TRADD, FADD, and RIPK1. NleB/SseKs GlcNAcylation of death domain proteins abrogates homotypic and heterotypic death receptors/adaptors interactions, thereby blocking an important antimicrobial host response. Interestingly, NleB/SseKs could also GlcNAcylate themselves, and self-GlcNAcylation of NleB, SseK1, and SseK3 are crucial for their biological activity during infection. In addition, EarP (EF-P specific arginine rhamnosyl transferase for Posttranslational activation) catalyzes arginine rhamnosylation of translation elongation factor P (EF-P). Importantly, this kind of N-linked protein glycosylation is not only important for EF-P dependent rescue of polyproline stalled ribosomes but also for pathogenicity in Pseudomonas aeruginosa and other clinically relevant bacteria. Glycosylation of arginine is unique because the guanidine group of arginine has a high acid dissociation constant value and representing an extremely poor nucleophile. Recently, the crystal structures of NleB, SseKs, EarP, arginine GlcNAcylated death domain-containing proteins, NleB/FADD-DD, and EarP/EF-P/dTDP-β-L-rhamnose were solved by our group and other groups, revealing the unique catalytic mechanisms. In this review, we provide detailed information about the currently known arginine glycosyltransferases and their potential catalytic mechanisms.
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Affiliation(s)
- Xing Pan
- Institute of Infection and Immunity, Taihe Hospital, Hubei University of Medicine, Shiyan, China.,College of Biomedicine and Health, Huazhong Agricultural University, Wuhan, China.,College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jie Luo
- Institute of Infection and Immunity, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Shan Li
- Institute of Infection and Immunity, Taihe Hospital, Hubei University of Medicine, Shiyan, China.,College of Biomedicine and Health, Huazhong Agricultural University, Wuhan, China.,College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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EspFu-Mediated Actin Assembly Enhances Enteropathogenic Escherichia coli Adherence and Activates Host Cell Inflammatory Signaling Pathways. mBio 2020; 11:mBio.00617-20. [PMID: 32291304 PMCID: PMC7157822 DOI: 10.1128/mbio.00617-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
EPEC is among the leading causes of diarrheal disease worldwide. The colonization of the gut mucosa by EPEC results in actin pedestal formation at the site of bacterial attachment. These pedestals are referred to as attaching and effacing (AE) lesions. Here, we exploit the different molecular mechanisms used by EPEC to induce AE lesions on epithelial cells, showing that the effector EspFu is associated with increased bacterial attachment and enhanced epithelial colonization compared to the Tir-Nck pathway. Moreover, we also showed that actin pedestal formation can counterbalance the anti-inflammatory activity induced by EPEC, especially when driven by EspFu. Collectively, our findings provide new insights into virulence mechanisms employed by EPEC to colonize epithelial cells, as well as the host response to this enteric pathogen. The translocation of effectors into the host cell through type 3 secretion systems (T3SS) is a sophisticated strategy employed by pathogenic bacteria to subvert host responses and facilitate colonization. Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) utilize the Tir and EspFu (also known as TccP) effectors to remodel the host cytoskeleton, culminating in the formation of attaching and effacing (AE) lesions on enterocytes. While some EPEC strains require tyrosine phosphorylation of Tir and recruitment of the host Nck to trigger actin polymerization, EHEC and certain EPEC strains, whose Tir is not phosphorylated, rely on the effector EspFu for efficient actin remodeling. Here, we investigated the role played by Tir-Nck and Tir-EspFu actin polymerization pathways during the infection of epithelial cells, as well as the host transcriptional response to the AE lesion formation induced by EPEC. We found that EspFu-mediated actin assembly promotes bacterial attachment and epithelial colonization more efficiently than Tir-Nck. Moreover, we showed that both actin polymerization mechanisms can activate inflammatory pathways and reverse the anti-inflammatory response induced by EPEC in epithelial cells. However, this activity is remarkably more evident in infections with EspFu-expressing EPEC strains. This study demonstrates the complex interactions between effector-mediated actin remodeling and inflammation. Different strains carry different combinations of these two effectors, highlighting the plasticity of pathogenic E. coli enteric infections.
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Lacey CA, Miao EA. Programmed Cell Death in the Evolutionary Race against Bacterial Virulence Factors. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a036459. [PMID: 31501197 DOI: 10.1101/cshperspect.a036459] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Innate immune sensors can recognize when host cells are irrevocably compromised by pathogens, and in response can trigger programmed cell death (pyroptosis, apoptosis, and necroptosis). Innate sensors can directly bind microbial ligands; for example, NAIP/NLRC4 detects flagellin/rod/needle, whereas caspase-11 detects lipopolysaccharide. Other sensors are guards that monitor normal function of cellular proteins; for instance, pyrin monitors Rho GTPases, whereas caspase-8 and receptor-interacting protein kinase (RIPK)3 guards RIPK1 transcriptional signaling. Some proteins that need to be guarded can be duplicated as decoy domains, as seen in the integrated decoy domains within NLRP1 that watch for microbial attack. Here, we discuss the evolutionary battle between pathogens and host innate immune sensors/guards, illustrated by the Red Queen hypothesis. We discuss in depth four pathogens, and how they either fail in this evolutionary race (Chromobacterium violaceum, Burkholderia thailandensis), or how the evolutionary race generates increasingly complex virulence factors and host innate immune signaling pathways (Yersinia species, and enteropathogenic Escherichia coli [EPEC]).
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Affiliation(s)
- Carolyn A Lacey
- Department of Microbiology and Immunology, Center for Gastrointestinal Biology and Disease, and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Edward A Miao
- Department of Microbiology and Immunology, Center for Gastrointestinal Biology and Disease, and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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44
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Tseytin I, Mitrovic B, David N, Langenfeld K, Zarivach R, Diepold A, Sal-Man N. The Role of the Small Export Apparatus Protein, SctS, in the Activity of the Type III Secretion System. Front Microbiol 2019; 10:2551. [PMID: 31798543 PMCID: PMC6863770 DOI: 10.3389/fmicb.2019.02551] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/22/2019] [Indexed: 12/15/2022] Open
Abstract
Many gram-negative pathogens utilize a protein complex, termed the type III secretion system (T3SS), to inject virulence factors from their cytoplasm directly into the host cell. An export apparatus that is formed by five putative integral membrane proteins (SctR/S/T/U/V), resides at the center of the T3SS complex. In this study, we characterized the smallest export apparatus protein, SctS, which contains two putative transmembrane domains (PTMD) that dynamically extract from the inner membrane and adopt a helix-turn-helix structure upon assembly of the T3SS. Replacement of each SctS PTMD with an alternative hydrophobic sequence resulted in abolishment of the T3SS activity, yet SctS self- and hetero-interactions as well as the overall assembly of the T3SS complex were unaffected. Our findings suggest that SctS PTMDs are not crucial for the interactions or the assembly of the T3SS base complex but rather that they are involved in adjusting the orientation of the export apparatus relative to additional T3SS sub-structures, such as the cytoplasmic- and the inner-membrane rings. This ensures the fittings between the dynamic and static components of the T3SS and supports the functionality of the T3SS complex.
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Affiliation(s)
- Irit Tseytin
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Bosko Mitrovic
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Nofar David
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Katja Langenfeld
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Raz Zarivach
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
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45
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Mesquita CS, Soares-Castro P, Faustino A, Santos HM, Capelo JL, Santos P. Identification of genomic loci associated with genotypic and phenotypic variation among Pseudomonas aeruginosa clinical isolates from pneumonia. Microb Pathog 2019; 136:103702. [PMID: 31472259 DOI: 10.1016/j.micpath.2019.103702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 11/19/2022]
Abstract
In this work, a genotype-phenotype survey of a highly diversified Pseudomonas aeruginosa collection was conducted, aiming to detail pathogen-associated scenarios that clinicians face nowadays. Genetic relation based on RAPD-PCR of 705 isolates, retrieved from 424 patients and several clinical contexts, reported an almost isolate-specific molecular-pattern. Pneumonia-associated isolates HB13 and HB15, clustered in the same RAPD-PCR group, were selected to evaluate the genomic background underlying their contrasting antibiotic resistance and virulence. The HB13 genome harbors antibiotic-inactivating enzymes-coding genes (e.g. aac(3)-Ia, arr, blaVIM-2) and single-nucleotide variations (SNVs) in antibiotic targets, likely accounting for its pan-resistance, whereas HB15 susceptibility correlated to predicted dysfunctional alleles. Isolate HB13 showed the unprecedented rhl-cluster absence and variations in other pathogen competitiveness contributors. Conversely, HB15 genome comprises exoenzyme-coding genes and SNVs linked to increased virulence. Secretome analysis identified signatures features with unknown function as potential novel pathogenic (e.g. a MATE-protein in HB13, a protease in HB15) and antibiotic resistance (a HlyD-like secretion protein in HB13) determinants. Detection of active prophages, proteases (including protease IV and alkaline metalloproteinase), a porin and a peptidase in HB15 highlights the secreted arsenal likely essential for its virulent behavior. The presented phenotype-genome association will contribute to the current knowledge on Pseudomonas aeruginosa pathogenomics.
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Affiliation(s)
- Cristina S Mesquita
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Pedro Soares-Castro
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Alberta Faustino
- Clinical Pathology Service, Hospital de Braga, 4710-243, Braga, Portugal
| | - Hugo M Santos
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal; PROTEOMASS Scientific Society, Madan Park, Rua dos Inventores, 2825-152, Caparica, Portugal
| | - José L Capelo
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal; PROTEOMASS Scientific Society, Madan Park, Rua dos Inventores, 2825-152, Caparica, Portugal
| | - Pedro Santos
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
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46
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Dorrington MG, Fraser IDC. NF-κB Signaling in Macrophages: Dynamics, Crosstalk, and Signal Integration. Front Immunol 2019; 10:705. [PMID: 31024544 PMCID: PMC6465568 DOI: 10.3389/fimmu.2019.00705] [Citation(s) in RCA: 404] [Impact Index Per Article: 80.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 03/14/2019] [Indexed: 12/12/2022] Open
Abstract
The nuclear factor-κB (NF-κB) signaling pathway is one of the best understood immune-related pathways thanks to almost four decades of intense research. NF-κB signaling is activated by numerous discrete stimuli and is a master regulator of the inflammatory response to pathogens and cancerous cells, as well as a key regulator of autoimmune diseases. In this regard, the role of NF-κB signaling in immunity is not unlike that of the macrophage. The dynamics by which NF-κB proteins shuttle between the cytoplasm and the nucleus to initiate transcription have been studied rigorously in fibroblasts and other non-hematopoietic cells, but many questions remain as to how current models of NF-κB signaling and dynamics can be translated to innate immune cells such as macrophages. In this review, we will present recent research on the dynamics of NF-κB signaling and focus especially on how these dynamics vary in different cell types, while discussing why these characteristics may be important. We will end by looking ahead to how new techniques and technologies should allow us to analyze these signaling processes with greater clarity, bringing us closer to a more complete understanding of inflammatory transcription factor dynamics and how different cellular contexts might allow for appropriate control of innate immune responses.
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Affiliation(s)
- Michael G Dorrington
- Signaling Systems Section, Laboratory of Immune System Biology, NIAID, DIR, NIH, Bethesda, MD, United States
| | - Iain D C Fraser
- Signaling Systems Section, Laboratory of Immune System Biology, NIAID, DIR, NIH, Bethesda, MD, United States
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47
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Gorelik O, Levy N, Shaulov L, Yegodayev K, Meijler MM, Sal-Man N. Vibrio cholerae autoinducer-1 enhances the virulence of enteropathogenic Escherichia coli. Sci Rep 2019; 9:4122. [PMID: 30858454 PMCID: PMC6411865 DOI: 10.1038/s41598-019-40859-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 02/25/2019] [Indexed: 12/19/2022] Open
Abstract
Diarrhoea is the second leading cause of death in children under the age of five. The bacterial species, Vibrio cholerae and enteropathogenic Escherichia coli (EPEC), are among the main pathogens that cause diarrhoeal diseases, which are associated with high mortality rates. These two pathogens have a common infection site-the small intestine. While it is known that both pathogens utilize quorum sensing (QS) to determine their population size, it is not yet clear whether potential bacterial competitors can also use this information. In this study, we examined the ability of EPEC to determine V. cholerae population sizes and to modulate its own virulence mechanisms accordingly. We found that EPEC virulence is enhanced in response to elevated concentrations of cholera autoinducer-1 (CAI-1), even though neither a CAI-1 synthase nor CAI-1 receptors have been reported in E. coli. This CAI-1 sensing and virulence upregulation response may facilitate the ability of EPEC to coordinate successful colonization of a host co-infected with V. cholerae. To the best of our knowledge, this is the first observed example of 'eavesdropping' between two bacterial pathogens that is based on interspecies sensing of a QS molecule.
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Affiliation(s)
- Orna Gorelik
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Niva Levy
- The Department of Chemistry and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Lihi Shaulov
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ksenia Yegodayev
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Michael M Meijler
- The Department of Chemistry and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Neta Sal-Man
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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Lin Z, Cheng Y, Wang RJ, Du J, Volovych O, Li JC, Hu Y, Lu ZY, Lu Z, Zou Z. A Metalloprotease Homolog Venom Protein From a Parasitoid Wasp Suppresses the Toll Pathway in Host Hemocytes. Front Immunol 2018; 9:2301. [PMID: 30405599 PMCID: PMC6206080 DOI: 10.3389/fimmu.2018.02301] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/17/2018] [Indexed: 12/18/2022] Open
Abstract
Parasitoid wasps depend on a variety of maternal virulence factors to ensure successful parasitism. Encapsulation response carried out by host hemocytes is one of the major host immune responses toward limiting endoparasitoid wasp offspring production. We found that VRF1, a metalloprotease homolog venom protein identified from the endoparasitoid wasp, Microplitis mediator, could modulate egg encapsulation in its host, the cotton bollworm, Helicoverpa armigera. Here, we show that the VRF1 proenzyme is cleaved after parasitism, and that the C-terminal fragment containing the catalytic domain enters host hemocytes 6 h post-parasitism. Furthermore, using yeast two-hybrid and pull-down assays, VRF1 is shown to interact with the H. armigera NF-κB factor, Dorsal. We also show that overexpressed of VRF1 in an H. armigera cell line cleaved Dorsal in vivo. Taken together, our results have revealed a novel mechanism by which a component of endoparasitoid wasp venom interferes with the Toll signaling pathway in the host hemocytes.
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Affiliation(s)
- Zhe Lin
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Yang Cheng
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Rui-Juan Wang
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Jie Du
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Olga Volovych
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Jian-Cheng Li
- Institute of Plant Protection of Hebei Academy of Agriculture and Forestry Sciences, Baoding, China
| | - Yang Hu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Zi-Yun Lu
- Institute of Plant Protection of Hebei Academy of Agriculture and Forestry Sciences, Baoding, China
| | - Zhiqiang Lu
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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49
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Cozier GE, Acharya KR. How a DNA mimic catches and cleaves NF-κB. J Biol Chem 2018; 293:15330-15331. [PMID: 30266880 DOI: 10.1074/jbc.h118.005528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bacterial pathogens use several strategies to infect host cells, one of which involves blocking host defenses. During infection, the bacterial effector proteins GtgA, GogA, PipA, and NleC are injected into host cells by the type III secretion system (T3SS), where they suppress the proinflammatory NF-κB signaling pathway to dampen immune responses. The authors demonstrate that these effectors bind NF-κB via their DNA-mimicking regions and uncover differences in effector sequences and structures explaining the individual specificities of these effectors for distinct NF-κB subunits.
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Affiliation(s)
- Gyles E Cozier
- From the Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - K Ravi Acharya
- From the Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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50
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Jennings E, Esposito D, Rittinger K, Thurston TLM. Structure-function analyses of the bacterial zinc metalloprotease effector protein GtgA uncover key residues required for deactivating NF-κB. J Biol Chem 2018; 293:15316-15329. [PMID: 30049795 PMCID: PMC6166728 DOI: 10.1074/jbc.ra118.004255] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/23/2018] [Indexed: 12/03/2022] Open
Abstract
The closely related type III secretion system zinc metalloprotease effector proteins GtgA, GogA, and PipA are translocated into host cells during Salmonella infection. They then cleave nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) transcription factor subunits, dampening activation of the NF-κB signaling pathway and thereby suppressing host immune responses. We demonstrate here that GtgA, GogA, and PipA cleave a subset of NF-κB subunits, including p65, RelB, and cRel but not NF-κB1 and NF-κB2, whereas the functionally similar type III secretion system effector NleC of enteropathogenic and enterohemorrhagic Escherichia coli cleaved all five NF-κB subunits. Mutational analysis of NF-κB subunits revealed that a single nonconserved residue in NF-κB1 and NF-κB2 that corresponds to the P1' residue Arg-41 in p65 prevents cleavage of these subunits by GtgA, GogA, and PipA, explaining the observed substrate specificity of these enzymes. Crystal structures of GtgA in its apo-form and in complex with the p65 N-terminal domain explained the importance of the P1' residue. Furthermore, the pattern of interactions suggested that GtgA recognizes NF-κB subunits by mimicking the shape and negative charge of the DNA phosphate backbone. Moreover, structure-based mutational analysis of GtgA uncovered amino acids that are required for the interaction of GtgA with p65, as well as those that are required for full activity of GtgA in suppressing NF-κB activation. This study therefore provides detailed and critical insight into the mechanism of substrate recognition by this family of proteins important for bacterial virulence.
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Affiliation(s)
- Elliott Jennings
- From the Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ and
| | - Diego Esposito
- the Molecular Structure of Cell Signalling Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, United Kingdom
| | - Katrin Rittinger
- the Molecular Structure of Cell Signalling Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, United Kingdom
| | - Teresa L M Thurston
- From the Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ and
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