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Saeedi P, Yazdanparast M, Behzadi E, Salmanian AH, Mousavi SL, Nazarian S, Amani J. A review on strategies for decreasing E. coli O157:H7 risk in animals. Microb Pathog 2017; 103:186-195. [PMID: 28062285 DOI: 10.1016/j.micpath.2017.01.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 12/25/2016] [Accepted: 01/02/2017] [Indexed: 11/17/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is a food-borne pathogen that younger children are most prone to this microorganism. Hemolytic Uremic Syndrome (HUS) caused by EHEC, leads to the destruction of red blood cells and kidney failure. The virulence of E.coli O157:H7 is attributed to fimbriae, that facilitate colonization of bacteria within the colon and verotoxins (VT) or Shiga toxins (Stx) that are released into the blood. Although, in most cases, the infection is self-limitedin young children and aged population, it may cause HUS. Therefore, several investigations are performed in order to offer effective therapies and vaccines, which can prevent and treat the infection in appropriate time. As the pathogenesis of this infection is complicated, a multi-targeted strategy is required. Since cattle are the most important reservoir of EHEC and the root of contamination, reducing E. coli O157:H7 at the farm level should decrease the risk of human illness. Several vaccine approaches have been employed with different proper outcomes in animal models, including recombinant proteins (virulence factors such as; Stx1/2, intimin, EspA, fusion proteins of A and B Stx subunits), avirulent ghost cells of EHEC O157:H7, live attenuated bacteria expressing recombinant proteins, recombinant fimbrial proteins. In addition to protein-based vaccines, DNA vaccines have provided proper prevention in the laboratory animal model. This review paper summarizes the previous studies, current status and future perspective of different immunization strategies for eradicating Enterohemorrhagic Escherichia coli O157:H7.
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Affiliation(s)
- Pardis Saeedi
- Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Maryam Yazdanparast
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
| | - Elham Behzadi
- Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Ali Hatef Salmanian
- Plant Bioproducts Department, Institute of Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Seyed Latif Mousavi
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
| | - Shahram Nazarian
- Department of Biology, Faculty of Science, Imam Hossein University, Tehran, Iran
| | - Jafar Amani
- Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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52
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Gomes TAT, Elias WP, Scaletsky ICA, Guth BEC, Rodrigues JF, Piazza RMF, Ferreira LCS, Martinez MB. Diarrheagenic Escherichia coli. Braz J Microbiol 2016; 47 Suppl 1:3-30. [PMID: 27866935 PMCID: PMC5156508 DOI: 10.1016/j.bjm.2016.10.015] [Citation(s) in RCA: 247] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 10/27/2016] [Indexed: 12/22/2022] Open
Abstract
Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes.
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Affiliation(s)
- Tânia A T Gomes
- Universidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Microbiologia, Imunologia e Parasitologia, São Paulo, SP, Brazil.
| | - Waldir P Elias
- Instituto Butantan, Laboratório de Bacterologia, São Paulo, SP, Brazil
| | - Isabel C A Scaletsky
- Universidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Microbiologia, Imunologia e Parasitologia, São Paulo, SP, Brazil
| | - Beatriz E C Guth
- Universidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Microbiologia, Imunologia e Parasitologia, São Paulo, SP, Brazil
| | - Juliana F Rodrigues
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil
| | - Roxane M F Piazza
- Instituto Butantan, Laboratório de Bacterologia, São Paulo, SP, Brazil
| | - Luís C S Ferreira
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil
| | - Marina B Martinez
- Universidade de São Paulo, Faculdade de Ciências Farmacêuticas, Departamento de Análises Clínicas e Toxicológicas, São Paulo, SP, Brazil
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Gaytán MO, Martínez-Santos VI, Soto E, González-Pedrajo B. Type Three Secretion System in Attaching and Effacing Pathogens. Front Cell Infect Microbiol 2016; 6:129. [PMID: 27818950 PMCID: PMC5073101 DOI: 10.3389/fcimb.2016.00129] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/27/2016] [Indexed: 02/06/2023] Open
Abstract
Enteropathogenic Escherichia coli and enterohemorrhagic E. coli are diarrheagenic bacterial human pathogens that cause severe gastroenteritis. These enteric pathotypes, together with the mouse pathogen Citrobacter rodentium, belong to the family of attaching and effacing pathogens that form a distinctive histological lesion in the intestinal epithelium. The virulence of these bacteria depends on a type III secretion system (T3SS), which mediates the translocation of effector proteins from the bacterial cytosol into the infected cells. The core architecture of the T3SS consists of a multi-ring basal body embedded in the bacterial membranes, a periplasmic inner rod, a transmembrane export apparatus in the inner membrane, and cytosolic components including an ATPase complex and the C-ring. In addition, two distinct hollow appendages are assembled on the extracellular face of the basal body creating a channel for protein secretion: an approximately 23 nm needle, and a filament that extends up to 600 nm. This filamentous structure allows these pathogens to get through the host cells mucus barrier. Upon contact with the target cell, a translocation pore is assembled in the host membrane through which the effector proteins are injected. Assembly of the T3SS is strictly regulated to ensure proper timing of substrate secretion. The different type III substrates coexist in the bacterial cytoplasm, and their hierarchical secretion is determined by specialized chaperones in coordination with two molecular switches and the so-called sorting platform. In this review, we present recent advances in the understanding of the T3SS in attaching and effacing pathogens.
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Affiliation(s)
- Meztlli O Gaytán
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Verónica I Martínez-Santos
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Eduardo Soto
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
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Humphreys D, Singh V, Koronakis V. Inhibition of WAVE Regulatory Complex Activation by a Bacterial Virulence Effector Counteracts Pathogen Phagocytosis. Cell Rep 2016; 17:697-707. [PMID: 27732847 PMCID: PMC5081413 DOI: 10.1016/j.celrep.2016.09.039] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 06/24/2016] [Accepted: 09/14/2016] [Indexed: 02/05/2023] Open
Abstract
To establish pathogenicity, bacteria must evade phagocytosis directed by remodeling of the actin cytoskeleton. We show that macrophages facilitate pathogen phagocytosis through actin polymerization mediated by the WAVE regulatory complex (WRC), small GTPases Arf and Rac1, and the Arf1 activator ARNO. To establish extracellular infections, enteropathogenic (EPEC) and enterohaemorrhagic (EHEC) Escherichia coli hijack the actin cytoskeleton by injecting virulence effectors into the host cell. Here, we find that the virulence effector EspG counteracts WRC-dependent phagocytosis, enabling EPEC and EHEC to remain extracellular. By reconstituting membrane-associated actin polymerization, we find that EspG disabled WRC activation through two mechanisms: EspG interaction with Arf6 blocked signaling to ARNO while EspG binding of Arf1 impeded collaboration with Rac1, thereby inhibiting WRC recruitment and activation. Investigating the mode of EspG interference revealed sites in Arf1 required for WRC activation and a mechanism facilitating pathogen evasion of innate host defenses.
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Affiliation(s)
- Daniel Humphreys
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
| | - Vikash Singh
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Vassilis Koronakis
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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55
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Rüter C, Schmidt MA. Cell-Penetrating Bacterial Effector Proteins: Better Tools than Targets. Trends Biotechnol 2016; 35:109-120. [PMID: 27592802 DOI: 10.1016/j.tibtech.2016.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 08/01/2016] [Accepted: 08/04/2016] [Indexed: 12/20/2022]
Abstract
Bacterial pathogens have developed intriguing virulence mechanisms, including several sophisticated nanomachines, for injecting effector proteins to manipulate host immune signaling pathways for their own benefit. Therefore, bacterial genomes harbor a wealth of information about how to manipulate the defense systems of the host. Current understanding addresses virulence mechanisms mostly as targets for antimicrobials. We propose a change of paradigm by exploiting bacterial effectors not as targets but as tools for the directed manipulation of host signaling - for the benefit of the host. Recently, effector proteins have been identified that autonomously translocate into host cells, representing a novel class of cell-penetrating peptides (CPPs) or effectors (CPEs). Moreover, autonomous cell penetration overcomes a major hurdle in pharmacology by transducing specific therapeutic agents to intracellular targets.
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Affiliation(s)
- Christian Rüter
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), Westfälische Wilhelms-Universität Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany.
| | - M Alexander Schmidt
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), Westfälische Wilhelms-Universität Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany.
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Yen H, Karino M, Tobe T. Modulation of the Inflammasome Signaling Pathway by Enteropathogenic and Enterohemorrhagic Escherichia coli. Front Cell Infect Microbiol 2016; 6:89. [PMID: 27617233 PMCID: PMC4999430 DOI: 10.3389/fcimb.2016.00089] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 08/11/2016] [Indexed: 01/07/2023] Open
Abstract
Innate immunity is an essential component in the protection of a host against pathogens. Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC, respectively) are known to modulate the innate immune responses of infected cells. The interference is dependent on their type III secretion system (T3SS) and T3SS-dependent effector proteins. Furthermore, these cytosolically injected effectors have been demonstrated to engage multiple immune signaling pathways, including the IFN/STAT, MAPK, NF-κB, and inflammasome pathways. In this review, recent work describing the interaction between EPEC/EHEC and the inflammasome pathway will be discussed.
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Affiliation(s)
- Hilo Yen
- Department of Biomedical Informatics, Graduate School of Medicine, Osaka University Osaka, Japan
| | - Masaki Karino
- Department of Biomedical Informatics, Graduate School of Medicine, Osaka University Osaka, Japan
| | - Toru Tobe
- Department of Biomedical Informatics, Graduate School of Medicine, Osaka University Osaka, Japan
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Sugar and Spice Make Bacteria Not Nice: Protein Glycosylation and Its Influence in Pathogenesis. J Mol Biol 2016; 428:3206-3220. [DOI: 10.1016/j.jmb.2016.04.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/04/2016] [Accepted: 04/08/2016] [Indexed: 01/08/2023]
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Serapio-Palacios A, Navarro-Garcia F. EspC, an Autotransporter Protein Secreted by Enteropathogenic Escherichia coli, Causes Apoptosis and Necrosis through Caspase and Calpain Activation, Including Direct Procaspase-3 Cleavage. mBio 2016; 7:e00479-16. [PMID: 27329750 PMCID: PMC4916375 DOI: 10.1128/mbio.00479-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/12/2016] [Indexed: 01/30/2023] Open
Abstract
UNLABELLED Enteropathogenic Escherichia coli (EPEC) has the ability to antagonize host apoptosis during infection through promotion and inhibition of effectors injected by the type III secretion system (T3SS), but the total number of these effectors and the overall functional relationships between these effectors during infection are poorly understood. EspC produced by EPEC cleaves fodrin, paxillin, and focal adhesion kinase (FAK), which are also cleaved by caspases and calpains during apoptosis. Here we show the role of EspC in cell death induced by EPEC. EspC is involved in EPEC-mediated cell death and induces both apoptosis and necrosis in epithelial cells. EspC induces apoptosis through the mitochondrial apoptotic pathway by provoking (i) a decrease in the expression levels of antiapoptotic protein Bcl-2, (ii) translocation of the proapoptotic protein Bax from cytosol to mitochondria, (iii) cytochrome c release from mitochondria to the cytoplasm, (iv) loss of mitochondrial membrane potential, (v) caspase-9 activation, (vi) cleavage of procaspase-3 and (vii) an increase in caspase-3 activity, (viii) PARP proteolysis, and (ix) nuclear fragmentation and an increase in the sub-G1 population. Interestingly, EspC-induced apoptosis was triggered through a dual mechanism involving both independent and dependent functions of its EspC serine protease motif, the direct cleavage of procaspase-3 being dependent on this motif. This is the first report showing a shortcut for induction of apoptosis by the catalytic activity of an EPEC protein. Furthermore, this atypical intrinsic apoptosis appeared to induce necrosis through the activation of calpain and through the increase of intracellular calcium induced by EspC. Our data indicate that EspC plays a relevant role in cell death induced by EPEC. IMPORTANCE EspC, an autotransporter protein with serine protease activity, has cytotoxic effects on epithelial cells during EPEC infection. EspC causes cytotoxicity by cleaving fodrin, a cytoskeletal actin-associated protein, and focal adhesion proteins (i.e., FAK); interestingly, these proteins are also cleaved during apoptosis and necrosis. Here we show that EspC is able to cause cell death, which is characterized by apoptosis: by dissecting the apoptotic pathway and considering that EspC is translocated by an injectisome, we found that EspC induces the mitochondrial apoptotic pathway. Remarkably, EspC activates this pathway by two distinct mechanisms-either by using or not using its serine protease motif. Thus, we show for the first time that this serine protease motif is able to cleave procaspase-3, thereby reaching the terminal stages of caspase cascade activation leading to apoptosis. Furthermore, this overlapped apoptosis appears to potentiate cell death through necrosis, where EspC induces calpain activation and increases intracellular calcium.
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Affiliation(s)
- Antonio Serapio-Palacios
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), México City, Mexico
| | - Fernando Navarro-Garcia
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), México City, Mexico
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59
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Abstract
Enterohemorrhagic Escherichia coli O157:H7 is a food-borne pathogen transmitted via the fecal-oral route, and can cause bloody diarrhea and hemolytic uremic syndrome (HUS) in the human host. Although a range of colonization factors, Shiga toxins and a type III secretion system (T3SS) all contribute to disease development, the locus of enterocyte effacement (LEE) encoded T3SS is responsible for the formation of lesions in the intestinal tract. While a variety of chemical cues in the host environment are known to up-regulate LEE expression, we recently demonstrated that changes in physical forces at the site of attachment are required for localized, full induction of the system and thus spatial regulation of virulence in the intestinal tract. Here, we discuss our findings in the light of other recent studies describing mechanosensing of the host and force-dependent induction of virulence mechanisms. We discuss potential mechanisms of mechanosensing and mechanotransduction, and the level of conservation across bacterial species.
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Affiliation(s)
- Md. Shahidul Islam
- Department of Biotechnology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Anne Marie Krachler
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
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Ruano-Gallego D, Álvarez B, Fernández LÁ. Engineering the Controlled Assembly of Filamentous Injectisomes in E. coli K-12 for Protein Translocation into Mammalian Cells. ACS Synth Biol 2015; 4:1030-41. [PMID: 26017572 PMCID: PMC4603727 DOI: 10.1021/acssynbio.5b00080] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
![]()
Bacterial pathogens containing type
III protein secretion systems
(T3SS) assemble large needle-like protein complexes in the bacterial
envelope, called injectisomes, for translocation of protein effectors
into host cells. The application of these “molecular syringes”
for the injection of proteins into mammalian cells is hindered by
their structural and genomic complexity, requiring multiple polypeptides
encoded along with effectors in various transcriptional units (TUs)
with intricate regulation. In this work, we have rationally designed
the controlled expression of the filamentous injectisomes found in
enteropathogenic Escherichia coli (EPEC) in the nonpathogenic strain E. coli K-12. All structural components of EPEC injectisomes, encoded in
a genomic island called the locus of enterocyte effacement
(LEE), were engineered in five TUs (eLEEs) excluding effectors, promoters
and transcriptional regulators. These eLEEs were placed under the
control of the IPTG-inducible promoter Ptac and integrated into specific
chromosomal sites of E. coli K-12 using a marker-less
strategy. The resulting strain, named synthetic injector E.
coli (SIEC), assembles filamentous injectisomes similar to
those in EPEC. SIEC injectisomes form pores in the host plasma membrane
and are able to translocate T3-substrate proteins (e.g., translocated intimin receptor, Tir) into the cytoplasm of HeLa
cells reproducing the phenotypes of intimate attachment and polymerization
of actin-pedestals elicited by EPEC bacteria. Hence, SIEC strain allows
the controlled expression of functional filamentous injectisomes for
efficient translocation of proteins with T3S-signals into mammalian
cells.
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Affiliation(s)
- David Ruano-Gallego
- Department of Microbial Biotechnology,
Centro Nacional de Biotecnología, Consejo Superior de Investigaciones
Científicas (CSIC), Campus UAM Cantoblanco, 28049 Madrid, Spain
| | - Beatriz Álvarez
- Department of Microbial Biotechnology,
Centro Nacional de Biotecnología, Consejo Superior de Investigaciones
Científicas (CSIC), Campus UAM Cantoblanco, 28049 Madrid, Spain
| | - Luis Ángel Fernández
- Department of Microbial Biotechnology,
Centro Nacional de Biotecnología, Consejo Superior de Investigaciones
Científicas (CSIC), Campus UAM Cantoblanco, 28049 Madrid, Spain
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