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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
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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
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A novel endoplasmic stress mediator, Kelch domain containing 7B (KLHDC7B), increased Harakiri (HRK) in the SubAB-induced apoptosis signaling pathway. Cell Death Discov 2021; 7:360. [PMID: 34799565 PMCID: PMC8605022 DOI: 10.1038/s41420-021-00753-0] [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] [Received: 08/26/2021] [Revised: 10/29/2021] [Accepted: 11/03/2021] [Indexed: 11/09/2022] Open
Abstract
Locus for Enterocyte Effacement (LEE)-positive Shiga-toxigenic Escherichia coli (STEC) contributes to many global foodborne diseases, with infection characterized by severe gastrointestinal symptoms, including bloody diarrhea. The incidence of LEE-negative STEC-mediated disease is also increasing globally. Subtilase cytotoxin (SubAB) is released by some LEE-negative STEC strains. It cleaves BiP, which is a chaperone protein located in the endoplasmic reticulum (ER), thereby causing apoptosis induced by ER stress. To date, the apoptotic signaling pathway mediated by SubAB has not been identified. In the current study, RNA-seq analysis showed that SubAB significantly induced the expression of Kelch domain containing 7B (KLHDC7B). We explored the role of KLHDC7B in the SubAB-induced apoptotic pathway. SubAB-induced KLHDC7B mRNA expression was increased after 12 h of incubation of toxin with HeLa cells. KLHDC7B expression was downregulated by knockdown of PKR-like endoplasmic reticulum kinase (PERK), CEBP homologous protein (CHOP), activating transcription factor 4 (ATF4), and CEBP β (CEBPB). KLHDC7B knockdown suppressed SubAB-stimulated CHOP expression, poly(ADP-ribose) polymerase (PARP) cleavage, and cytotoxicity. The over-expressed KLHDC7B was localized to the nucleus and cytosolic fractions. Next, we used RNA-seq to analyze the effect of KLHDC7B knockdown on apoptosis induced by SubAB, and found that the gene encoding for the pro-apoptotic Bcl-2 family protein, Harakiri (HRK), was upregulated in SubAB-treated control cells. However, this effect was not observed in SubAB-treated KLHDC7B-knockdown cells. Therefore, we identified the pathway through which SubAB-induced KLHDC7B regulates HRK expression, which is essential for apoptosis in toxin-mediated ER stress.
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Subtilase cytotoxin induces a novel form of Lipocalin 2, which promotes Shiga-toxigenic Escherichia coli survival. Sci Rep 2020; 10:18943. [PMID: 33144618 PMCID: PMC7609767 DOI: 10.1038/s41598-020-76027-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 10/20/2020] [Indexed: 01/11/2023] Open
Abstract
Shiga-toxigenic Escherichia coli (STEC) infection causes severe bloody diarrhea, renal failure, and hemolytic uremic syndrome. Recent studies showed global increases in Locus for Enterocyte Effacement (LEE)-negative STEC infection. Some LEE-negative STEC produce Subtilase cytotoxin (SubAB), which cleaves endoplasmic reticulum (ER) chaperone protein BiP, inducing ER stress and apoptotic cell death. In this study, we report that SubAB induces expression of a novel form of Lipocalin-2 (LCN2), and describe its biological activity and effects on apoptotic cell death. SubAB induced expression of a novel LCN2, which was regulated by PRKR-like endoplasmic reticulum kinase via the C/EBP homologous protein pathway. SubAB-induced novel-sized LCN2 was not secreted into the culture supernatant. Increased intracellular iron level by addition of holo-transferrin or FeCl3 suppressed SubAB-induced PARP cleavage. Normal-sized FLAG-tagged LCN2 suppressed STEC growth, but this effect was not seen in the presence of SubAB- or tunicamycin-induced unglycosylated FLAG-tagged LCN2. Our study demonstrates that SubAB-induced novel-sized LCN2 does not have anti-STEC activity, suggesting that SubAB plays a crucial role in the survival of LEE-negative STEC as well as inducing apoptosis of the host cells.
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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.
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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
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Desvaux M, Dalmasso G, Beyrouthy R, Barnich N, Delmas J, Bonnet R. Pathogenicity Factors of Genomic Islands in Intestinal and Extraintestinal Escherichia coli. Front Microbiol 2020; 11:2065. [PMID: 33101219 PMCID: PMC7545054 DOI: 10.3389/fmicb.2020.02065] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/05/2020] [Indexed: 12/20/2022] Open
Abstract
Escherichia coli is a versatile bacterial species that includes both harmless commensal strains and pathogenic strains found in the gastrointestinal tract in humans and warm-blooded animals. The growing amount of DNA sequence information generated in the era of "genomics" has helped to increase our understanding of the factors and mechanisms involved in the diversification of this bacterial species. The pathogenic side of E. coli that is afforded through horizontal transfers of genes encoding virulence factors enables this bacterium to become a highly diverse and adapted pathogen that is responsible for intestinal or extraintestinal diseases in humans and animals. Many of the accessory genes acquired by horizontal transfers form syntenic blocks and are recognized as genomic islands (GIs). These genomic regions contribute to the rapid evolution, diversification and adaptation of E. coli variants because they are frequently subject to rearrangements, excision and transfer, as well as to further acquisition of additional DNA. Here, we review a subgroup of GIs from E. coli termed pathogenicity islands (PAIs), a concept defined in the late 1980s by Jörg Hacker and colleagues in Werner Goebel's group at the University of Würzburg, Würzburg, Germany. As with other GIs, the PAIs comprise large genomic regions that differ from the rest of the genome by their G + C content, by their typical insertion within transfer RNA genes, and by their harboring of direct repeats (at their ends), integrase determinants, or other mobility loci. The hallmark of PAIs is their contribution to the emergence of virulent bacteria and to the development of intestinal and extraintestinal diseases. This review summarizes the current knowledge on the structure and functional features of PAIs, on PAI-encoded E. coli pathogenicity factors and on the role of PAIs in host-pathogen interactions.
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Affiliation(s)
- Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, Clermont-Ferrand, France
| | - Guillaume Dalmasso
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Racha Beyrouthy
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Nicolas Barnich
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Julien Delmas
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Richard Bonnet
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
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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]
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Yahiro K, Ogura K, Terasaki Y, Satoh M, Miyagi S, Terasaki M, Yamasaki E, Moss J. Cholix toxin, an eukaryotic elongation factor 2 ADP-ribosyltransferase, interacts with Prohibitins and induces apoptosis with mitochondrial dysfunction in human hepatocytes. Cell Microbiol 2019; 21:e13033. [PMID: 31009148 PMCID: PMC9986844 DOI: 10.1111/cmi.13033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/16/2019] [Indexed: 12/12/2022]
Abstract
Vibrio cholerae produced-Cholix toxin (Cholix) is a cytotoxin that ADP-ribosylates eukaryotic elongation factor 2, inhibiting protein synthesis, and inducing apoptosis. Here, we identified prohibitin (PHB) 1 and 2 as novel Cholix-interacting membrane proteins in immortalised human hepatocytes and HepG2 cells by Cholix immunoprecipitation assays. The expression level of PHB1 was decreased by Cholix after a 12hr incubation. Cholix-induced poly (ADP-ribose) polymerase (PARP) cleavage was significantly enhanced in PHB (PHB1 or PHB2) knockdown cells. In contrast, transiently overexpressed PHB in hepatocytes attenuated Cholix-induced Bax/Bak conformational changes and PARP cleavage. In addition, Cholix-induced reactive oxygen species production and accumulation of fragmented mitochondria were enhanced in PHB-knockdown cells. Furthermore, Cholix induced activation of Rho-associated coiled coil-containing protein kinase 1 (ROCK1), which was enhanced in PHB-knockdown cells, followed by actin filament depolymerisation and accumulation of tubulin in the blebbing cells. Inhibition of ROCK1 by siRNA or its inhibitor suppressed Cholix-induced PARP cleavage and reactive oxygen species generation. Our findings identify PHB as a new protein that interacts with Cholix and is involved in Cholix-induced mitochondrial dysfunction and cytoskeletal rearrangement by ROCK1 activation during apoptosis.
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Affiliation(s)
- Kinnosuke Yahiro
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Kohei Ogura
- Advanced Health Care Science Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Japan
| | - Yasuhiro Terasaki
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Mamoru Satoh
- Division of Clinical Mass Spectrometry, Chiba University Hospital, Chiba, Japan
| | - Satoru Miyagi
- Department of Life Science, Faculty of Medicine, Shimane University, Izumo, Japan
| | - Mika Terasaki
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Eiki Yamasaki
- Diagnostic Center for Animal Health and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan
| | - Joel Moss
- Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
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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.
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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
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El-Aouar Filho RA, Nicolas A, De Paula Castro TL, Deplanche M, De Carvalho Azevedo VA, Goossens PL, Taieb F, Lina G, Le Loir Y, Berkova N. Heterogeneous Family of Cyclomodulins: Smart Weapons That Allow Bacteria to Hijack the Eukaryotic Cell Cycle and Promote Infections. Front Cell Infect Microbiol 2017; 7:208. [PMID: 28589102 PMCID: PMC5440457 DOI: 10.3389/fcimb.2017.00208] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/09/2017] [Indexed: 12/13/2022] Open
Abstract
Some bacterial pathogens modulate signaling pathways of eukaryotic cells in order to subvert the host response for their own benefit, leading to successful colonization and invasion. Pathogenic bacteria produce multiple compounds that generate favorable conditions to their survival and growth during infection in eukaryotic hosts. Many bacterial toxins can alter the cell cycle progression of host cells, impairing essential cellular functions and impeding host cell division. This review summarizes current knowledge regarding cyclomodulins, a heterogeneous family of bacterial effectors that induce eukaryotic cell cycle alterations. We discuss the mechanisms of actions of cyclomodulins according to their biochemical properties, providing examples of various cyclomodulins such as cycle inhibiting factor, γ-glutamyltranspeptidase, cytolethal distending toxins, shiga toxin, subtilase toxin, anthrax toxin, cholera toxin, adenylate cyclase toxins, vacuolating cytotoxin, cytotoxic necrotizing factor, Panton-Valentine leukocidin, phenol soluble modulins, and mycolactone. Special attention is paid to the benefit provided by cyclomodulins to bacteria during colonization of the host.
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Affiliation(s)
- Rachid A El-Aouar Filho
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France.,Departamento de Biologia Geral, Laboratório de Genética Celular e Molecular (LGCM), Instituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Aurélie Nicolas
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
| | - Thiago L De Paula Castro
- Departamento de Biologia Geral, Laboratório de Genética Celular e Molecular (LGCM), Instituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Martine Deplanche
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
| | - Vasco A De Carvalho Azevedo
- Departamento de Biologia Geral, Laboratório de Genética Celular e Molecular (LGCM), Instituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Pierre L Goossens
- HistoPathologie et Modèles Animaux/Pathogénie des Toxi-Infections Bactériennes, Institut PasteurParis, France
| | - Frédéric Taieb
- CHU Purpan USC INRA 1360-CPTP, U1043 Institut National de la Santé et de la Recherche Médicale, Pathogénie Moléculaire et Cellulaire des Infections à Escherichia coliToulouse, France
| | - Gerard Lina
- International Center for Infectiology ResearchLyon, France.,Centre National de la Recherche Scientifique, UMR5308, Institut National de la Santé et de la Recherche Médicale U1111, Ecole Normale Supérieure de Lyon, Université Lyon 1Lyon, France.,Département de Biologie, Institut des Agents Infectieux, Hospices Civils de LyonLyon, France
| | - Yves Le Loir
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
| | - Nadia Berkova
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
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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.
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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
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11
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Cytotoxic and apoptotic effects of recombinant subtilase cytotoxin variants of shiga toxin-producing Escherichia coli. Infect Immun 2015; 83:2338-49. [PMID: 25824835 DOI: 10.1128/iai.00231-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 03/20/2015] [Indexed: 12/24/2022] Open
Abstract
In this study, the cytotoxicity of the recently described subtilase variant SubAB2-2 of Shiga toxin-producing Escherichia coli was determined and compared to the plasmid-encoded SubAB1 and the chromosome-encoded SubAB2-1 variant. The genes for the respective enzymatic active (A) subunits and binding (B) subunits of the subtilase toxins were amplified and cloned. The recombinant toxin subunits were expressed and purified. Their cytotoxicity on Vero cells was measured for the single A and B subunits, as well as for mixtures of both, to analyze whether hybrids with toxic activity can be identified. The results demonstrated that all three SubAB variants are toxic for Vero cells. However, the values for the 50% cytotoxic dose (CD50) differ for the individual variants. Highest cytotoxicity was shown for SubAB1. Moreover, hybrids of subunits from different subtilase toxins can be obtained which cause substantial cytotoxicity to Vero cells after mixing the A and B subunits prior to application to the cells, which is characteristic for binary toxins. Furthermore, higher concentrations of the enzymatic subunit SubA1 exhibited cytotoxic effects in the absence of the respective B1 subunit. A more detailed investigation in the human HeLa cell line revealed that SubA1 alone induced apoptosis, while the B1 subunit alone did not induce cell death.
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DAP1, a negative regulator of autophagy, controls SubAB-mediated apoptosis and autophagy. Infect Immun 2014; 82:4899-908. [PMID: 25183729 DOI: 10.1128/iai.02213-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Autophagy and apoptosis play critical roles in cellular homeostasis and survival. Subtilase cytotoxin (SubAB), produced by non-O157 type Shiga-toxigenic Escherichia coli (STEC), is an important virulence factor in disease. SubAB, a protease, cleaves a specific site on the endoplasmic reticulum (ER) chaperone protein BiP/GRP78, leading to ER stress, and induces apoptosis. Here we report that in HeLa cells, activation of a PERK (RNA-dependent protein kinase [PKR]-like ER kinase)-eIF2α (α subunit of eukaryotic initiation factor 2)-dependent pathway by SubAB-mediated BiP cleavage negatively regulates autophagy and induces apoptosis through death-associated protein 1 (DAP1). We found that SubAB treatment decreased the amounts of autophagy markers LC3-II and p62 as well as those of mTOR (mammalian target of rapamycin) signaling proteins ULK1 and S6K. These proteins showed increased expression levels in PERK knockdown or DAP1 knockdown cells. In addition, depletion of DAP1 in HeLa cells dramatically inhibited the SubAB-stimulated apoptotic pathway: SubAB-induced Bax/Bak conformational changes, Bax/Bak oligomerization, cytochrome c release, activation of caspases, and poly(ADP-ribose) polymerase (PARP) cleavage. These results show that DAP1 is a key regulator, through PERK-eIF2α-dependent pathways, of the induction of apoptosis and reduction of autophagy by SubAB.
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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.
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Affiliation(s)
- Sayaka Nagasawa
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, Chiba, 260-8670, Japan
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Michelacci V, Tozzoli R, Caprioli A, Martínez R, Scheutz F, Grande L, Sánchez S, Morabito S. A new pathogenicity island carrying an allelic variant of the Subtilase cytotoxin is common among Shiga toxin producing Escherichia coli of human and ovine origin. Clin Microbiol Infect 2013; 19:E149-56. [PMID: 23331629 DOI: 10.1111/1469-0691.12122] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 11/30/2012] [Accepted: 12/02/2012] [Indexed: 11/26/2022]
Abstract
Subtilase (SubAB) is a cytotoxin elaborated by some Shiga Toxin (Stx)-producing Escherichia coli (STEC) strains usually lacking the locus of enterocyte effacement (LEE). Two variants of SubAB coding genes have been described: subAB(1) , located on the plasmid of the STEC O113 98NK2 strain, and subAB(2) , located on a pathogenicity island (PAI) together with the tia gene, encoding an invasion determinant described in enterotoxigenic E. coli. In the present study, we determined the entire nucleotide sequence of the PAI containing the subAB(2) operon, termed Subtilase-Encoding PAI (SE-PAI), and identified its integration site in the pheV tRNA locus. In addition, a PCR strategy for discriminating the two subAB allelic variants was developed and used to investigate their presence in E. coli strains belonging to different pathotypes and in a large collection of LEE-negative STEC of human and ovine origin. The results confirmed that subAB genes are carried predominantly by STEC and showed their presence in 72% and 86% of the LEE-negative strains from human cases of diarrhoea and from healthy sheep respectively. Most of the subAB-positive strains (98%) identified possessed the subAB(2) allelic variant and were also positive for tia, suggesting the presence of SE-PAI. Altogether, our observations indicate that subAB(2) is the prevalent SubAB-coding operon in LEE-negative STEC circulating in European countries, and that sheep may represent an important reservoir for human infections with these strains. Further studies are needed to assess the role of tia and/or other genes carried by SE-PAI in the colonization of the host intestinal mucosa.
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Affiliation(s)
- V Michelacci
- European Reference Laboratory for Escherichia coli, Istituto Superiore di Sanità, Dipartimento di Sanità Pubblica Veterinaria e Sicurezza Alimentare, Rome, Italy
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