1
|
Harada A, Tsutsuki H, Zhang T, Yahiro K, Sawa T, Niidome T. Controlled Delivery of an Anti-Inflammatory Toxin to Macrophages by Mutagenesis and Nanoparticle Modification. NANOMATERIALS 2022; 12:nano12132161. [PMID: 35807998 PMCID: PMC9268525 DOI: 10.3390/nano12132161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 02/05/2023]
Abstract
Advances in drug delivery systems (DDSs) have enabled the specific delivery of drugs to target cells. Subtilase cytotoxin (SubAB) produced by certain enterohemorrhagic Escherichia coli strains induces endoplasmic reticulum (ER) stress and suppresses nitric oxide generation in macrophages. We previously reported that modification of SubAB with poly(D,L-lactide-co-glycolic) acid (PLGA) nanoparticles (SubAB-PLGA NPs) increased intracellular uptake of SubAB and had an anti-inflammatory effect on macrophages. However, specific delivery of SubAB to macrophages could not be achieved because its effects on other cell types were not negligible. Therefore, to suppress non-specific SubAB binding, we used low-binding mutant SubABS35A (S35A) in which the 35th serine of the B subunit was mutated to alanine. In a macrophage cell line, PLGA NPs modified with S35A (S35A-PLGA NPs) induced ER stress and had anti-inflammatory effects similar to WT-PLGA NPs. However, in an epithelial cell line, S35A-PLGA NPs induced lower ER stress than WT-PLGA NPs. These results suggest that S35A is selectively delivered to macrophages rather than epithelial cells by modification with PLGA NPs and exerts anti-inflammatory effects. Our findings provide a useful technique for protein delivery to macrophages and encourage medical applications of DDSs for the treatment of inflammatory diseases.
Collapse
Affiliation(s)
- Ayaka Harada
- Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan;
| | - Hiroyasu Tsutsuki
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; (H.T.); (T.Z.); (T.S.)
| | - Tianli Zhang
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; (H.T.); (T.Z.); (T.S.)
| | - Kinnosuke Yahiro
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan;
| | - Tomohiro Sawa
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; (H.T.); (T.Z.); (T.S.)
| | - Takuro Niidome
- Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan;
- Correspondence:
| |
Collapse
|
2
|
Tsutsuki H, Zhang T, Yahiro K, Ono K, Fujiwara Y, Iyoda S, Wei FY, Monde K, Seto K, Ohnishi M, Oshiumi H, Akaike T, Sawa T. Subtilase cytotoxin from Shiga-toxigenic Escherichia coli impairs the inflammasome and exacerbates enteropathogenic bacterial infection. iScience 2022; 25:104050. [PMID: 35345462 PMCID: PMC8957020 DOI: 10.1016/j.isci.2022.104050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/08/2022] [Accepted: 03/08/2022] [Indexed: 01/18/2023] Open
Abstract
Subtilase cytotoxin (SubAB) is an AB5 toxin mainly produced by the locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli (STEC) strain such as O113:H21, yet the contribution of SubAB to STEC infectious disease is unclear. We found that SubAB reduced activation of the STEC O113:H21 infection-induced non-canonical NLRP3 inflammasome and interleukin (IL)-1β and IL-18 production in murine macrophages. Downstream of lipopolysaccharide signaling, SubAB suppressed caspase-11 expression by inhibiting interferon-β/STAT1 signaling, followed by disrupting formation of the NLRP3/caspase-1 assembly. These inhibitions were regulated by PERK/IRE1α-dependent endoplasmic reticulum (ER) stress signaling initiated by cleavage of the host ER chaperone BiP by SubAB. Our murine model of SubAB-producing Citrobacter rodentium demonstrated that SubAB promoted C. rodentium proliferation and worsened symptoms such as intestinal hyperplasia and diarrhea. These findings highlight the inhibitory effect of SubAB on the NLRP3 inflammasome via ER stress, which may be associated with STEC survival and infectious disease pathogenicity in hosts. SubAB from STEC inhibits inflammasome activation and IL-1β/IL-18 production SubAB prevents caspase-11 expression via IRE1α/PERK-dependent inhibition of STAT1 SubAB reduces LPS-induced pro-IL-1β production via IRE1α/PERK-dependent pathway SubAB promotes C. rodentium survival in mouse colon and facilitates the infection
Collapse
Affiliation(s)
- Hiroyasu Tsutsuki
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
- Corresponding author
| | - Tianli Zhang
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Kinnosuke Yahiro
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Katsuhiko Ono
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Yukio Fujiwara
- Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Chuo-ku, Kumamoto 860-8556, Japan
| | - Sunao Iyoda
- Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Fan-Yan Wei
- Department of Modomics Biology and Medicine, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Kazuaki Monde
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Kazuko Seto
- Quality Assurance Unit, Division of Planning, Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka 537-0025, Japan
| | - Makoto Ohnishi
- Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Hiroyuki Oshiumi
- Department of Immunology, Graduate School of Medical Sciences, Kumamoto University, Chuo-ku, Kumamoto 860-8556, Japan
| | - Takaaki Akaike
- Department of Environmental Medicine and Molecular Toxicology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Tomohiro Sawa
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
- Corresponding author
| |
Collapse
|
3
|
Tsutsuki H, Ogura K, Moss J, Yahiro K. Host response to the subtilase cytotoxin produced by locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli. Microbiol Immunol 2020; 64:657-665. [PMID: 32902863 DOI: 10.1111/1348-0421.12841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/05/2020] [Accepted: 09/07/2020] [Indexed: 12/26/2022]
Abstract
Shiga-toxigenic Escherichia coli (STEC) is a major bacterium responsible for disease resulting from foodborne infection, including bloody diarrhea and hemolytic uremic syndrome. STEC produces important virulence factors such as Shiga toxin (Stx) 1 and/or 2. In the STEC family, some locus of enterocyte effacement-negative STEC produce two different types of cytotoxins, namely, Stx2 and subtilase cytotoxin (SubAB). The Stx2 and SubAB cytotoxins are structurally similar and composed of one A subunit and pentamer of B subunits. The catalytically active A subunit of SubAB is a subtilase-like serine protease and specifically cleaves an endoplasmic reticulum (ER) chaperone 78-kDa glucose-regulated protein (GRP78/BiP), a monomeric ATPase that is crucial in protein folding and quality control. The B subunit binds to cell surface receptors. SubAB recognizes sialic carbohydrate-modified cell surface proteins as a receptor. After translocation into cells, SubAB is delivered to the ER, where it cleaves GRP78/BiP. SubAB-catalyzed BiP cleavage induces ER stress, which causes various cell events including inhibition of protein synthesis, suppression of nuclear factor-kappa B activation, apoptotic cell death, and stress granules formation. In this review, we describe SubAB, the SubAB receptor, and the mechanism of cell response to the toxin.
Collapse
Affiliation(s)
- Hiroyasu Tsutsuki
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Kohei Ogura
- Advanced Health Care Science Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Japan
| | - Joel Moss
- Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Kinnosuke Yahiro
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| |
Collapse
|
4
|
Wyrsch ER, Chowdhury PR, Jarocki VM, Brandis KJ, Djordjevic SP. Duplication and diversification of a unique chromosomal virulence island hosting the subtilase cytotoxin in Escherichia coli ST58. Microb Genom 2020; 6:e000387. [PMID: 32519937 PMCID: PMC7371111 DOI: 10.1099/mgen.0.000387] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 05/18/2020] [Indexed: 12/17/2022] Open
Abstract
The AB5 cytotoxins are important virulence factors in Escherichia coli. The most notable members of the AB5 toxin families include Shiga toxin families 1 (Stx1) and 2 (Stx2), which are associated with enterohaemorrhagic E. coli infections causing haemolytic uraemic syndrome and haemorrhagic colitis. The subAB toxins are the newest and least well understood members of the AB5 toxin gene family. The subtilase toxin genes are divided into a plasmid-based variant, subAB1, originally described in enterohaemorrhagic E. coli O113:H21, and distinct chromosomal variants, subAB2, that reside in pathogenicity islands encoding additional virulence effectors. Previously we identified a chromosomal subAB2 operon within an E. coli ST58 strain IBS28 (ONT:H25) taken from a wild ibis nest at an inland wetland in New South Wales, Australia. Here we show the subAB2 toxin operon comprised part of a 140 kb tRNA-Phe chromosomal island that co-hosted tia, encoding an outer-membrane protein that confers an adherence and invasion phenotype and additional virulence and accessory genetic content that potentially originated from known virulence island SE-PAI. This island shared a common evolutionary history with a secondary 90 kb tRNA-Phe pathogenicity island that was presumably generated via a duplication event. IBS28 is closely related [200 single-nucleotide polymorphisms (SNPs)] to four North American ST58 strains. The close relationship between North American isolates of ST58 and IBS28 was further supported by the identification of the only copy of a unique variant of IS26 within the O-antigen gene cluster. Strain ISB28 may be a historically important E. coli ST58 genome sequence hosting a progenitor pathogenicity island encoding subAB.
Collapse
Affiliation(s)
- Ethan R. Wyrsch
- ithree institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
- The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Piklu Roy Chowdhury
- ithree institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
- The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Veronica M. Jarocki
- ithree institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
- The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Kate J. Brandis
- Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington 2052 NSW, Australia
| | - Steven P. Djordjevic
- ithree institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
- The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, NSW 2007, Australia
| |
Collapse
|
5
|
Tsutsuki H, Zhang T, Harada A, Rahman A, Ono K, Yahiro K, Niidome T, Sawa T. Involvement of protein disulfide isomerase in subtilase cytotoxin-induced cell death in HeLa cells. Biochem Biophys Res Commun 2020; 525:1068-1073. [DOI: 10.1016/j.bbrc.2020.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 03/03/2020] [Indexed: 12/01/2022]
|
6
|
Krause M, Sessler K, Kaziales A, Grahl R, Noettger S, Barth H, Schmidt H. Variants of Escherichia coli Subtilase Cytotoxin Subunits Show Differences in Complex Formation In Vitro. Toxins (Basel) 2019; 11:toxins11120703. [PMID: 31816894 PMCID: PMC6950094 DOI: 10.3390/toxins11120703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 11/19/2019] [Accepted: 11/27/2019] [Indexed: 12/11/2022] Open
Abstract
The subtilase cytotoxin (SubAB) of Shiga toxin-producing Escherichia coli (STEC) is a member of the AB5 toxin family. In the current study, we analyzed the formation of active homo- and hetero-complexes of SubAB variants in vitro to characterize the mode of assembly of the subunits. Recombinant SubA1-His, SubB1-His, SubA2-2-His, and SubB2-2-His subunits, and His-tag-free SubA2-2 were separately expressed, purified, and biochemically characterized by circular dichroism (CD) spectroscopy, size-exclusion chromatography (SEC), and analytical ultracentrifugation (aUC). To confirm their biological activity, cytotoxicity assays were performed with HeLa cells. The formation of AB5 complexes was investigated with aUC and isothermal titration calorimetry (ITC). Binding of SubAB2-2-His to HeLa cells was characterized with flow cytometry (FACS). Cytotoxicity experiments revealed that the analyzed recombinant subtilase subunits were biochemically functional and capable of intoxicating HeLa cells. Inhibition of cytotoxicity by Brefeldin A demonstrated that the cleavage is specific. All His-tagged subunits, as well as the non-tagged SubA2-2 subunit, showed the expected secondary structural compositions and oligomerization. Whereas SubAB1-His complexes could be reconstituted in solution, and revealed a Kd value of 3.9 ± 0.8 μmol/L in the lower micromolar range, only transient interactions were observed for the subunits of SubAB2-2-His in solution, which did not result in any binding constant when analyzed with ITC. Additional studies on the binding characteristics of SubAB2-2-His on HeLa cells revealed that the formation of transient complexes improved binding to the target cells. Conclusively, we hypothesize that SubAB variants exhibit different characteristics in their binding behavior to their target cells.
Collapse
Affiliation(s)
- Maike Krause
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, Garbenstraße 28, University of Hohenheim, 70599 Stuttgart, Germany; (M.K.); (R.G.)
| | - Katharina Sessler
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (K.S.); (S.N.); (H.B.)
| | - Anna Kaziales
- Center for Integrated Protein Science Munich, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany;
| | - Richard Grahl
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, Garbenstraße 28, University of Hohenheim, 70599 Stuttgart, Germany; (M.K.); (R.G.)
| | - Sabrina Noettger
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (K.S.); (S.N.); (H.B.)
| | - Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (K.S.); (S.N.); (H.B.)
| | - Herbert Schmidt
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, Garbenstraße 28, University of Hohenheim, 70599 Stuttgart, Germany; (M.K.); (R.G.)
- Correspondence: ; Tel.: +49-711-459-22305
| |
Collapse
|
7
|
A CRISPR Screen Using Subtilase Cytotoxin Identifies SLC39A9 as a Glycan-Regulating Factor. iScience 2019; 15:407-420. [PMID: 31108395 PMCID: PMC6526310 DOI: 10.1016/j.isci.2019.05.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 03/26/2019] [Accepted: 05/03/2019] [Indexed: 01/29/2023] Open
Abstract
Subtilase cytotoxin (SubAB) is a virulence factor produced by locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli strains. The toxin recognizes sialoglycans for entry and cleaves an endoplasmic reticulum chaperon, binding immunoglobulin protein, to cause cell death. However, no systematic screening has yet been performed to identify critical host factors. Here, we performed a genome-wide CRISPR/Cas9 knockout screen for SubAB-induced cell death and identified various sialoglycan-related and membrane-trafficking genes. Analysis of glycan-deficient cells demonstrated that not only N-glycans but also O-glycans serve as SubAB receptors. In addition, SLC39A9, which is a predicted zinc transporter, as well as KDELRs and JTB, were required for SubAB to induce maximal cell death. Disruption of the SLC39A9 gene markedly reduced both complex-type N-glycans and core 1 O-glycans, and the O-glycan reduction was attributed to the reduction of core 1 synthase (C1GalT1). These results provide insights into the post-transcriptional regulation of glycosyltransferases by SLC39A9, as well as sialoglycan species as SubAB receptors.
Collapse
|
8
|
Zhang T, Ono K, Tsutsuki H, Ihara H, Islam W, Akaike T, Sawa T. Enhanced Cellular Polysulfides Negatively Regulate TLR4 Signaling and Mitigate Lethal Endotoxin Shock. Cell Chem Biol 2019; 26:686-698.e4. [DOI: 10.1016/j.chembiol.2019.02.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/03/2018] [Accepted: 01/31/2019] [Indexed: 01/04/2023]
|
9
|
Lang C, Fruth A, Holland G, Laue M, Mühlen S, Dersch P, Flieger A. Novel type of pilus associated with a Shiga-toxigenic E. coli hybrid pathovar conveys aggregative adherence and bacterial virulence. Emerg Microbes Infect 2018; 7:203. [PMID: 30514915 PMCID: PMC6279748 DOI: 10.1038/s41426-018-0209-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/09/2018] [Accepted: 11/11/2018] [Indexed: 01/31/2023]
Abstract
A large German outbreak in 2011 was caused by a locus of enterocyte effacement (LEE)-negative enterohemorrhagic E. coli (EHEC) strain of the serotype O104:H4. This strain harbors markers that are characteristic of both EHEC and enteroaggregative E. coli (EAEC), including aggregative adhesion fimbriae (AAF) genes. Such rare EHEC/EAEC hybrids are highly pathogenic due to their possession of a combination of genes promoting severe toxicity and aggregative adhesion. We previously identified novel EHEC/EAEC hybrids and observed that one strain exhibited aggregative adherence but had no AAF genes. In this study, a genome sequence analysis showed that this strain belongs to the genoserotype O23:H8, MLST ST26, and harbors a 5.2 Mb chromosome and three plasmids. One plasmid carries some EAEC marker genes, such as aatA and genes with limited protein homology (11–61%) to those encoding the bundle-forming pilus (BFP) of enteropathogenic E. coli. Due to significant protein homology distance to known pili, we designated these as aggregate-forming pili (AFP)-encoding genes and the respective plasmid as pAFP. The afp operon was arranged similarly to the operon of BFP genes but contained an additional gene, afpA2, which is homologous to afpA. The deletion of the afp operon, afpA, or a nearby gene (afpR) encoding an AraC-like regulator, but not afpA2, led to a loss of pilin production, piliation, bacterial autoaggregation, and importantly, a >80% reduction in adhesion and cytotoxicity toward epithelial cells. Gene sets similar to the afp operon were identified in a variety of aatA-positive but AAF-negative intestinal pathogenic E. coli. In summary, we characterized widely distributed and novel fimbriae that are essential for aggregative adherence and cytotoxicity in a LEE-negative Shiga-toxigenic hybrid.
Collapse
Affiliation(s)
- Christina Lang
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institut, Wernigerode, Saxony-Anhalt, 38855, Germany
| | - Angelika Fruth
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institut, Wernigerode, Saxony-Anhalt, 38855, Germany
| | - Gudrun Holland
- Division of Advanced Light and Electron Microscopy, Robert Koch Institut, Berlin, 13353, Germany
| | - Michael Laue
- Division of Advanced Light and Electron Microscopy, Robert Koch Institut, Berlin, 13353, Germany
| | - Sabrina Mühlen
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Lower Saxony, 38124, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Lower Saxony, 38124, Germany
| | - Antje Flieger
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institut, Wernigerode, Saxony-Anhalt, 38855, Germany.
| |
Collapse
|
10
|
Krause M, Barth H, Schmidt H. Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli. Toxins (Basel) 2018; 10:toxins10060241. [PMID: 29903982 PMCID: PMC6024878 DOI: 10.3390/toxins10060241] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/07/2018] [Accepted: 06/12/2018] [Indexed: 12/16/2022] Open
Abstract
Studies on Shiga toxin-producing Escherichia coli (STEC) typically examine and classify the virulence gene profiles based on genomic analyses. Among the screened strains, a subgroup of STEC which lacks the locus of enterocyte effacement (LEE) has frequently been identified. This raises the question about the level of pathogenicity of such strains. This review focuses on the advantages and disadvantages of the standard screening procedures in virulence profiling and summarizes the current knowledge concerning the function and regulation of toxins encoded by LEE-negative STEC. Although LEE-negative STEC usually come across as food isolates, which rarely cause infections in humans, some serotypes have been implicated in human diseases. In particular, the LEE-negative E. coli O104:H7 German outbreak strain from 2011 and the Australian O113:H21 strain isolated from a HUS patient attracted attention. Moreover, the LEE-negative STEC O113:H21 strain TS18/08 that was isolated from minced meat is remarkable in that it not only encodes multiple toxins, but in fact expresses three different toxins simultaneously. Their characterization contributes to understanding the virulence of the LEE-negative STEC.
Collapse
Affiliation(s)
- Maike Krause
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany.
| | - Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Herbert Schmidt
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany.
| |
Collapse
|
11
|
Yahiro K, Nagasawa S, Ichimura K, Takeuchi H, Ogura K, Tsutsuki H, Shimizu T, Iyoda S, Ohnishi M, Iwase H, Moss J, Noda M. Mechanism of inhibition of Shiga-toxigenic Escherichia coli SubAB cytotoxicity by steroids and diacylglycerol analogues. Cell Death Discov 2018. [PMID: 29531819 PMCID: PMC5841432 DOI: 10.1038/s41420-017-0007-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Shiga toxigenic Escherichia coli (STEC) are responsible for a worldwide foodborne disease, which is characterized by severe bloody diarrhea and hemolytic uremic syndrome (HUS). Subtilase cytotoxin (SubAB) is a novel AB5 toxin, which is produced by Locus for Enterocyte Effacement (LEE)-negative STEC. Cleavage of the BiP protein by SubAB induces endoplasmic reticulum (ER) stress, followed by induction of cytotoxicity in vitro or lethal severe hemorrhagic inflammation in mice. Here we found that steroids and diacylglycerol (DAG) analogues (e.g., bryostatin 1, Ingenol-3-angelate) inhibited SubAB cytotoxicity. In addition, steroid-induced Bcl-xL expression was a key step in the inhibition of SubAB cytotoxicity. Bcl-xL knockdown increased SubAB-induced apoptosis in steroid-treated HeLa cells, whereas SubAB-induced cytotoxicity was suppressed in Bcl-xL overexpressing cells. In contrast, DAG analogues suppressed SubAB activity independent of Bcl-xL expression at early time points. Addition of Shiga toxin 2 (Stx2) with SubAB to cells enhanced cytotoxicity even in the presence of steroids. In contrast, DAG analogues suppressed cytotoxicity seen in the presence of both toxins. Here, we show the mechanism by which steroids and DAG analogues protect cells against SubAB toxin produced by LEE-negative STEC.
Collapse
Affiliation(s)
- Kinnosuke Yahiro
- 1Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Sayaka Nagasawa
- 2Department of Legal Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Kimitoshi Ichimura
- 1Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Hiroki Takeuchi
- 1Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Kohei Ogura
- 3Pathogenic Microbe Laboratory, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Hiroyasu Tsutsuki
- 4Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Takeshi Shimizu
- 1Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Sunao Iyoda
- 5Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Makoto Ohnishi
- 5Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hirotaro Iwase
- 2Department of Legal Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Joel Moss
- 6Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Masatoshi Noda
- 1Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| |
Collapse
|
12
|
Type Three Secretion System-Dependent Microvascular Thrombosis and Ischemic Enteritis in Human Gut Xenografts Infected with Enteropathogenic Escherichia coli. Infect Immun 2017; 85:IAI.00558-17. [PMID: 28784929 DOI: 10.1128/iai.00558-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 08/04/2017] [Indexed: 01/01/2023] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) is a leading cause of severe intestinal disease and infant mortality in developing countries. Virulence is mediated by a type three secretion system (T3SS), causing the hallmark attaching and effacing (AE) lesions and actin-rich pedestal formation beneath the infecting bacteria on the apical surface of enterocytes. EPEC is a human-specific pathogen whose pathogenesis cannot be studied in animal models. We therefore established an EPEC infection model in human gut xenografts in SCID mice and used it to study the role of T3SS in the pathogenesis of the disease. Following EPEC O127:H6 strain E2348/69 infection, T3SS-dependent AE lesions and pedestals were demonstrated in all infected xenografts. We report here the development of T3SS-dependent intestinal thrombotic microangiopathy (iTMA) and ischemic enteritis in ∼50% of infected human gut xenografts. Using species-specific CD31 immunostaining, we showed that iTMA was limited to the larger human-mouse chimeric blood vessels, which are located between the muscularis mucosa and circular muscular layer of the human gut. These blood vessels were massively invaded by bacteria, which adhered to and formed pedestals on endothelial cells and aggregated with mouse neutrophils in the lumen. We conclude that endothelial infection, iTMA, and ischemic enteritis might be central mechanisms underlying severe EPEC-mediated disease.
Collapse
|
13
|
Seyahian EA, Oltra G, Ochoa F, Melendi S, Hermes R, Paton JC, Paton AW, Lago N, Castro Parodi M, Damiano A, Ibarra C, Zotta E. Systemic effects of Subtilase cytotoxin produced by Escherichia coli O113:H21. Toxicon 2017; 127:49-55. [PMID: 28057514 DOI: 10.1016/j.toxicon.2016.12.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 12/28/2016] [Accepted: 12/31/2016] [Indexed: 01/08/2023]
Abstract
Subtilase cytotoxin (SubAB) is a member of the AB5 cytotoxin family and is produced by certain strains of Shiga toxigenic Escherichia coli. The toxin is known to be lethal to mice, but the pathological mechanisms that contribute to Uremic Hemolytic Syndrome (HUS) are poorly understood. In this study we show that intraperitoneal injection of a sublethal dose of SubAB in rats triggers a systemic response, with ascitic fluid accumulation, heart hypertrophy and damage to the liver, colon and kidney. SubAB treated rats presented microalbuminuria 20 days post inoculation. At this time we found disruption of the glomerular filtration barrier and alteration of the protein reabsorption mechanisms of the proximal tubule. In the kidney, SubAB also triggered an epithelial to mesenchymal transition (Wuyts et al., 1996). These findings indicate that apart from direct cytotoxic effects on renal tissues, SubAB causes significant damage to the other organs, with potential consequences for HUS pathogenesis. IMPORTANCE Uremic Hemolytic Syndrome is an endemic disease in Argentina, with over 400 hundred new cases each year. We have previously described renal effects of Shiga Toxin and its ability to alter renal protein handling. Bearing in mind that Subtilase Cytotoxin is an emerging pathogenic factor, that it is not routinely searched for in patients with HUS, and that to the date its systemic effects have not been fully clarified we decided to study both its systemic effects, and its renal effects to assess whether SubAB could be contributing to pathology seen in children.
Collapse
Affiliation(s)
- E Abril Seyahian
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Fisiología y Biofísica IFIBIO Houssay-CONICET, Argentina
| | - Gisela Oltra
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Fisiología y Biofísica IFIBIO Houssay-CONICET, Argentina
| | - Federico Ochoa
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Fisiología y Biofísica IFIBIO Houssay-CONICET, Argentina
| | - Santiago Melendi
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Fisiología y Biofísica IFIBIO Houssay-CONICET, Argentina
| | - Ricardo Hermes
- Hospital de Agudos Juan A. Fernandez, Laboratorio Central, Argentina
| | - James C Paton
- University of Adelaide, Department of Molecular and Cellular Biology, Research Centre for Infectious Diseases, Australia
| | - Adrienne W Paton
- University of Adelaide, Department of Molecular and Cellular Biology, Research Centre for Infectious Diseases, Australia
| | - Nestor Lago
- Universidad de Buenos Aires, Facultad de Medicina, Laboratorio de Patología Experimental y Aplicada, Argentina
| | - Mauricio Castro Parodi
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Fisiología y Biofísica IFIBIO Houssay-CONICET, Argentina
| | - Alicia Damiano
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Fisiología y Biofísica IFIBIO Houssay-CONICET, Argentina
| | - Cristina Ibarra
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Fisiología y Biofísica IFIBIO Houssay-CONICET, Argentina
| | - Elsa Zotta
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Fisiología y Biofísica IFIBIO Houssay-CONICET, Argentina; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Fisiopatología, Buenos Aires, Argentina.
| |
Collapse
|
14
|
Tsutsuki H, Yahiro K, Ogura K, Ichimura K, Iyoda S, Ohnishi M, Nagasawa S, Seto K, Moss J, Noda M. Subtilase cytotoxin produced by locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli induces stress granule formation. Cell Microbiol 2016; 18:1024-40. [PMID: 26749168 PMCID: PMC10068837 DOI: 10.1111/cmi.12565] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 12/24/2015] [Accepted: 01/06/2016] [Indexed: 12/13/2022]
Abstract
Subtilase cytotoxin (SubAB) is mainly produced by locus of enterocyte effacement (LEE)-negative strains of Shiga-toxigenic Escherichia coli (STEC). SubAB cleaves an endoplasmic reticulum (ER) chaperone, BiP/Grp78, leading to induction of ER stress. This stress causes activation of ER stress sensor proteins and induction of caspase-dependent apoptosis. We found that SubAB induces stress granules (SG) in various cells. Aim of this study was to explore the mechanism by which SubAB induced SG formation. Here, we show that SubAB-induced SG formation is regulated by activation of double-stranded RNA-activated protein kinase (PKR)-like endoplasmic reticulum kinase (PERK). The culture supernatant of STEC O113:H21 dramatically induced SG in Caco2 cells, although subAB knockout STEC O113:H21 culture supernatant did not. Treatment with phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, and lysosomal inhibitors, NH4 Cl and chloroquine, suppressed SubAB-induced SG formation, which was enhanced by PKC and PKD inhibitors. SubAB attenuated the level of PKD1 phosphorylation. Depletion of PKCδ and PKD1 by siRNA promoted SG formation in response to SubAB. Furthermore, death-associated protein 1 (DAP1) knockdown increased basal phospho-PKD1(S916) and suppressed SG formation by SubAB. However, SG formation by an ER stress inducer, Thapsigargin, was not inhibited in PMA-treated cells. Our findings show that SubAB-induced SG formation is regulated by the PERK/DAP1 signalling pathway, which may be modulated by PKCδ/PKD1, and different from the signal transduction pathway that results in Thapsigargin-induced SG formation.
Collapse
Affiliation(s)
- Hiroyasu Tsutsuki
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Kinnosuke Yahiro
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Kohei Ogura
- Pathogenic Microbe Laboratory, Research Institute, National Centre for Global Health and Medicine, Tokyo, Japan
| | - Kimitoshi Ichimura
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Sunao Iyoda
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Makoto Ohnishi
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Sayaka Nagasawa
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Kazuko Seto
- Division of Bacteriology, Osaka Prefectural Institute of Public Health, Osaka, Japan
| | - Joel Moss
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Masatoshi Noda
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| |
Collapse
|
15
|
Hauser E, Bruederle M, Reich C, Bruckbauer A, Funk J, Schmidt H. Subtilase contributes to the cytotoxicity of a Shiga toxin-producing Escherichia coli strain encoding three different toxins. Int J Food Microbiol 2015; 217:156-61. [PMID: 26523884 DOI: 10.1016/j.ijfoodmicro.2015.10.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/15/2015] [Accepted: 10/23/2015] [Indexed: 11/24/2022]
Abstract
Food-borne Shiga toxin-producing Escherichia coli (STEC) O113:H21 strain TS18/08, that has previously been isolated from mixed minced meat, harbors the Shiga toxin (Stx) encoding allele stx2a, the plasmid-located subtilase cytotoxin encoding allele subAB1 and the cytolethal distending toxin type V encoding gene cdt-V. In the current study, it could be shown that each of these toxin genes was transcribed with different transcription levels at different time points by RT real time PCR under laboratory batch conditions in LB-broth. The transcription maximum for cdt-V and subAB1 was observed after 3h while stx2a transcription was highest after 6h of incubation. During this time the mean relationship of the amount of stx2a:subAB1:cdt-V transcripts was 1:26:100. Furthermore, isogenic stx2a and cdt-V chromosomal deletion mutants were constructed to measure the contribution of SubAB1 to the overall cytotoxicity of this strain. In this context, a further copy of stx2 was detected in this strain and was also deleted. Comparing the cytotoxicity of supernatants of the resulting mutant strains TS18/08-3 (Δstx2-1Δstx2-2Δcdt-V) and TS18/08-4 (Δstx2-1Δstx2-2Δcdt-VΔsubAB1) on Vero cells demonstrated a contribution of SubAB1 to the overall cytotoxic effect while the 4-fold isogenic deletion mutant did not show any cytotoxic effect and that was comparable to the non-toxic laboratory E. coli strain C600. The cytotoxic effect could be restored by complementation with the recombinant low copy plasmid pWSK29 harboring subAB1 under the control of its own promoter. In addition, the cytotoxicity of wild type strain TS18/08 to Vero cells was in the same range as the EHEC O157:H7 strain EDL933. Therefore, food-borne STEC O113:H21 strain TS18/08 can be considered as a putative human pathogen.
Collapse
Affiliation(s)
- Elisabeth Hauser
- Institute of Food Science and Biotechnology, Department of Food Microbiology and Hygiene, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany
| | - Matthias Bruederle
- Institute of Food Science and Biotechnology, Department of Food Microbiology and Hygiene, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany
| | - Carolin Reich
- Institute of Food Science and Biotechnology, Department of Food Microbiology and Hygiene, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany
| | - Annette Bruckbauer
- Institute of Food Science and Biotechnology, Department of Food Microbiology and Hygiene, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany
| | - Joschua Funk
- Institute of Food Science and Biotechnology, Department of Food Microbiology and Hygiene, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany
| | - Herbert Schmidt
- Institute of Food Science and Biotechnology, Department of Food Microbiology and Hygiene, Garbenstrasse 28, University of Hohenheim, 70599 Stuttgart, Germany.
| |
Collapse
|
16
|
Nagasawa S, Ogura K, Tsutsuki H, Saitoh H, Moss J, Iwase H, Noda M, Yahiro K. Uptake of Shiga-toxigenic Escherichia coli SubAB by HeLa cells requires an actin- and lipid raft-dependent pathway. Cell Microbiol 2014; 16:1582-601. [PMID: 24844382 DOI: 10.1111/cmi.12315] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 05/07/2014] [Accepted: 05/08/2014] [Indexed: 02/06/2023]
Abstract
The novel cytotoxic factor subtilase cytotoxin (SubAB) is produced mainly by non-O157 Shiga-toxigenic Escherichia coli (STEC). SubAB cleaves the molecular chaperone BiP/GRP78 in the endoplasmic reticulum (ER), leading to activation of RNA-dependent protein kinase (PKR)-like ER kinase (PERK), followed by caspase-dependent cell death. However, the SubAB uptake mechanism in HeLa cells is unknown. In this study, a variety of inhibitors and siRNAs were employed to characterize the SubAB uptake process. SubAB-induced BiP cleavage was inhibited by high concentrations of Dynasore, and methyl-β-cyclodextrin (mβCD) and Filipin III, but not suppressed in clathrin-, dynamin I/II-, caveolin1- and caveolin2-knockdown cells. We observed that SubAB treatment led to dramatic actin rearrangements, e.g. formation of plasma membrane blebs, with a significant increase in fluid uptake. Confocal microscopy analysis showed that SubAB uptake required actin cytoskeleton remodelling and lipid raft cholesterol. Furthermore, internalized SubAB in cells was found in the detergent-resistant domain (DRM) structure. Interestingly, IPA-3, an inhibitor of serine/threonine kinase p21-activated kinase (PAK1), an important protein of macropinocytosis, directly inhibited SubAB-mediated BiP cleavage and SubAB internalization. Thus, our findings suggest that SubAB uses lipid raft- and actin-dependent, but not clathrin-, caveolin- and dynamin-dependent pathways as its major endocytic translocation route.
Collapse
Affiliation(s)
- Sayaka Nagasawa
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, Chiba, 260-8670, Japan
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Differential effects of Escherichia coli subtilase cytotoxin and Shiga toxin 2 on chemokine and proinflammatory cytokine expression in human macrophage, colonic epithelial, and brain microvascular endothelial cell lines. Infect Immun 2014; 82:3567-79. [PMID: 24914216 DOI: 10.1128/iai.02120-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Subtilase cytotoxin (SubAB) is the prototype of a recently emerged family of AB5 cytotoxins produced by Shiga-toxigenic Escherichia coli (STEC). Its mechanism of action involves highly specific A-subunit-mediated proteolytic cleavage of the essential endoplasmic reticulum (ER) chaperone BiP. Our previous in vivo studies showed that intraperitoneal injection of purified SubAB causes a major redistribution of leukocytes and elevated leukocyte apoptosis in mice, as well as profound splenic atrophy. In the current study, we investigated selected chemokine and proinflammatory cytokine responses to treatment with SubAB, a nontoxic derivative (SubAA272B), or Shiga toxin 2 (Stx2) in human macrophage (U937), brain microvascular endothelial (HBMEC), and colonic epithelial (HCT-8) cell lines, at the levels of secreted protein, cell-associated protein, and gene expression. Stx2 treatment upregulated expression of chemokines and cytokines at both the protein and mRNA levels. In contrast, SubAB induced significant decreases in secreted interleukin-8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) in all three tested cell lines and a significant decrease in secreted IL-6 in HBMECs. The downregulation of secreted chemokines or cytokines was not observed in SubAA272B-treated cells, indicating a requirement for BiP cleavage. The downregulation of secreted chemokines and cytokines by SubAB was not reflected at the mRNA and cell-associated protein levels, suggesting a SubAB-induced export defect.
Collapse
|
18
|
Croxen MA, Law RJ, Scholz R, Keeney KM, Wlodarska M, Finlay BB. Recent advances in understanding enteric pathogenic Escherichia coli. Clin Microbiol Rev 2013; 26:822-80. [PMID: 24092857 PMCID: PMC3811233 DOI: 10.1128/cmr.00022-13] [Citation(s) in RCA: 823] [Impact Index Per Article: 74.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.
Collapse
|
19
|
Noda M. [Studies on the mode of action of bacterial AB5 toxins]. Nihon Saikingaku Zasshi 2013; 68:299-311. [PMID: 23985936 DOI: 10.3412/jsb.68.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Bacterial AB5 toxins are proteins, produced by pathogenic bacteria including of Vibrio cholerae, Shigella dysenteriae, and enterohaemorrhagic Escherichia coli, which are usually released into the extracellular medium and cause disease by killing or altering the metabolism of target eukaryotic cells. The toxins are usually composed of one A subunit (a toxic domain) and five B subunits (a receptor-binding domain). This article overviews the characteristics and mode of actions of AB5 toxins including cholera toxin, Shiga-like toxin, and subtilase cytotoxin, and highlights current topics related to the roles of the effectors in promoting bacterial infection.
Collapse
Affiliation(s)
- Masatoshi Noda
- Department of Molecular Infectiology, Chiba University Graduate School of Medicine, Japan
| |
Collapse
|
20
|
Bauwens A, Betz J, Meisen I, Kemper B, Karch H, Müthing J. Facing glycosphingolipid-Shiga toxin interaction: dire straits for endothelial cells of the human vasculature. Cell Mol Life Sci 2013; 70:425-57. [PMID: 22766973 PMCID: PMC11113656 DOI: 10.1007/s00018-012-1060-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 05/25/2012] [Accepted: 06/14/2012] [Indexed: 12/23/2022]
Abstract
The two major Shiga toxin (Stx) types, Stx1 and Stx2, produced by enterohemorrhagic Escherichia coli (EHEC) in particular injure renal and cerebral microvascular endothelial cells after transfer from the human intestine into the circulation. Stxs are AB(5) toxins composed of an enzymatically active A subunit and the pentameric B subunit, which preferentially binds to the glycosphingolipid globotriaosylceramide (Gb3Cer/CD77). This review summarizes the current knowledge on Stx-caused cellular injury and the structural diversity of Stx receptors as well as the initial molecular interaction of Stxs with the human endothelium of different vascular beds. The varying lipoforms of Stx receptors and their spatial organization in lipid rafts suggest a central role in different modes of receptor-mediated endocytosis and intracellular destiny of the toxins. The design and development of tailored Stx neutralizers targeting the oligosaccharide-toxin recognition event has become a very real prospect to ameliorate or prevent life-threatening renal and neurological complications.
Collapse
Affiliation(s)
- Andreas Bauwens
- Institute for Hygiene, University of Münster, Robert-Koch-Str. 41, 48149 Münster, Germany
| | - Josefine Betz
- Institute for Hygiene, University of Münster, Robert-Koch-Str. 41, 48149 Münster, Germany
| | - Iris Meisen
- Institute for Hygiene, University of Münster, Robert-Koch-Str. 41, 48149 Münster, Germany
- Interdisciplinary Center for Clinical Research, University of Münster, Domagkstr. 3, 48149 Münster, Germany
| | - Björn Kemper
- Center for Biomedical Optics and Photonics, University of Münster, Robert-Koch-Str. 45, 48149 Münster, Germany
| | - Helge Karch
- Institute for Hygiene, University of Münster, Robert-Koch-Str. 41, 48149 Münster, Germany
| | - Johannes Müthing
- Institute for Hygiene, University of Münster, Robert-Koch-Str. 41, 48149 Münster, Germany
- Interdisciplinary Center for Clinical Research, University of Münster, Domagkstr. 3, 48149 Münster, Germany
| |
Collapse
|
21
|
Subtilase cytotoxin enhances Escherichia coli survival in macrophages by suppression of nitric oxide production through the inhibition of NF-κB activation. Infect Immun 2012; 80:3939-51. [PMID: 22949549 DOI: 10.1128/iai.00581-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Subtilase cytotoxin (SubAB), which is produced by certain strains of Shiga-toxigenic Escherichia coli (STEC), cleaves an endoplasmic reticulum (ER) chaperone, BiP/Grp78, leading to induction of ER stress and caspase-dependent apoptosis. SubAB alters the innate immune response. SubAB pretreatment of macrophages inhibited lipopolysaccharide (LPS)-induced production of both monocyte chemoattractant protein 1 (MCP-1) and tumor necrosis factor α (TNF-α). We investigated here the mechanism by which SubAB inhibits nitric oxide (NO) production by mouse macrophages. SubAB suppressed LPS-induced NO production through inhibition of inducible NO synthase (iNOS) mRNA and protein expression. Further, SubAB inhibited LPS-induced IκB-α phosphorylation and nuclear localization of the nuclear factor-κB (NF-κB) p65/p50 heterodimer. Reporter gene and chromatin immunoprecipitation (ChIP) assays revealed that SubAB reduced LPS-induced NF-κB p65/p50 heterodimer binding to an NF-κB binding site on the iNOS promoter. In contrast to the native toxin, a catalytically inactivated SubAB mutant slightly enhanced LPS-induced iNOS expression and binding of NF-κB subunits to the iNOS promoter. The SubAB effect on LPS-induced iNOS expression was significantly reduced in macrophages from NF-κB1 (p50)-deficient mice, which lacked a DNA-binding subunit of the p65/p50 heterodimer, suggesting that p50 was involved in SubAB-mediated inhibition of iNOS expression. Treatment of macrophages with an NOS inhibitor or expression of SubAB by E. coli increased E. coli survival in macrophages, suggesting that NO generated by macrophages resulted in efficient killing of the bacteria and SubAB contributed to E. coli survival in macrophages. Thus, we hypothesize that SubAB might represent a novel bacterial strategy to circumvent host defense during STEC infection.
Collapse
|
22
|
Regulation of subtilase cytotoxin-induced cell death by an RNA-dependent protein kinase-like endoplasmic reticulum kinase-dependent proteasome pathway in HeLa cells. Infect Immun 2012; 80:1803-14. [PMID: 22354021 DOI: 10.1128/iai.06164-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Shiga-toxigenic Escherichia coli (STEC) produces subtilase cytotoxin (SubAB), which cleaves the molecular chaperone BiP in the endoplasmic reticulum (ER), leading to an ER stress response and then activation of apoptotic signaling pathways. Here, we show that an early event in SubAB-induced apoptosis in HeLa cells is mediated by RNA-dependent protein kinase (PKR)-like ER kinase (PERK), not activating transcription factor 6 (ATF6) or inositol-requiring enzyme 1(Ire1), two other ER stress sensors. PERK knockdown suppressed SubAB-induced eIF2α phosphorylation, activating transcription factor 4 (ATF4) expression, caspase activation, and cytotoxicity. Knockdown of eIF2α by small interfering RNA (siRNA) or inhibition of eIF2α dephosphorylation by Sal003 enhanced SubAB-induced caspase activation. Treatment with proteasome inhibitors (i.e., MG132 and lactacystin), but not a general caspase inhibitor (Z-VAD) or a lysosome inhibitor (chloroquine), suppressed SubAB-induced caspase activation and poly(ADP-ribose) polymerase (PARP) cleavage, suggesting that the ubiquitin-proteasome system controls events leading to caspase activation, i.e., Bax/Bak conformational changes, followed by cytochrome c release from mitochondria. Levels of ubiquitinated proteins in HeLa cells were significantly decreased by SubAB treatment. Further, in an early event, some antiapoptotic proteins, which normally turn over rapidly, have their synthesis inhibited, and show enhanced degradation via the proteasome, resulting in apoptosis. In PERK knockdown cells, SubAB-induced loss of ubiquitinated proteins was inhibited. Thus, SubAB-induced ER stress is caused by BiP cleavage, leading to PERK activation, not by accumulation of ubiquitinated proteins, which undergo PERK-dependent degradation via the ubiquitin-proteasome system.
Collapse
|