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Tucker SK, McHugh RE, Roe AJ. One problem, multiple potential targets: Where are we now in the development of small molecule inhibitors against Shiga toxin? Cell Signal 2024; 121:111253. [PMID: 38852937 DOI: 10.1016/j.cellsig.2024.111253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/04/2024] [Accepted: 06/06/2024] [Indexed: 06/11/2024]
Abstract
Shiga toxin-producing Escherichia coli (STEC) are a group of enteric pathogens which carry phage-encoded Shiga toxins (Stx). STEC infections begin with severe abdominal pain and non-bloody diarrhoea, which can progress to bloody diarrhoea after approximately 4-days post-infection. In high-risk groups such as children and the elderly, patients may develop haemolytic uremic syndrome (HUS). HUS is characterised by microangiopathic haemolytic anaemia, thrombocytopenia, and in severe disease acute renal failure. Traditional antibiotics have been linked with increased toxin production due to the activation of recA-mediated bacterial stress response, resulting in poorer patient outcomes. Therefore, treatment relies on supportive therapies. Antivirulence strategies have been explored as an alternative treatment for bacterial infections and blockers of virulence factors such as the Type III Secretion System. Recent improvements in the mechanistic understanding of the Stx pathway have led to the design of inhibitors to disrupt the pathway, leading to toxin-mediated ribosome damage. However, compounds have yet to progress beyond Phase III clinical trials successfully. This review explores the progress in developing small molecule inhibitors by collating lead compounds derived from in-silico and experimental approaches.
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Affiliation(s)
- Samantha K Tucker
- School of Infection and Immunity, University of Glasgow, Glasgow G12 8TA, United Kingdom
| | - Rebecca E McHugh
- School of Infection and Immunity, University of Glasgow, Glasgow G12 8TA, United Kingdom
| | - Andrew J Roe
- School of Infection and Immunity, University of Glasgow, Glasgow G12 8TA, United Kingdom.
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2
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Hwang SB, Chelliah R, Kang JE, Rubab M, Banan-MwineDaliri E, Elahi F, Oh DH. Role of Recent Therapeutic Applications and the Infection Strategies of Shiga Toxin-Producing Escherichia coli. Front Cell Infect Microbiol 2021; 11:614963. [PMID: 34268129 PMCID: PMC8276698 DOI: 10.3389/fcimb.2021.614963] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 05/07/2021] [Indexed: 12/17/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a global foodborne bacterial pathogen that is often accountable for colon disorder or distress. STEC commonly induces severe diarrhea in hosts but can cause critical illnesses due to the Shiga toxin virulence factors. To date, there have been a significant number of STEC serotypes have been evolved. STECs vary from nausea and hemorrhoid (HC) to possible lethal hemolytic-based uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP). Inflammation-based STEC is usually a foodborne illness with Shiga toxins (Stx 1 and 2) thought to be pathogenesis. The STEC's pathogenicity depends significantly on developing one or more Shiga toxins, which can constrain host cell protein synthesis leading to cytotoxicity. In managing STEC infections, antimicrobial agents are generally avoided, as bacterial damage and discharge of accumulated toxins are thought the body. It has also been documented that certain antibiotics improve toxin production and the development of these species. Many different groups have attempted various therapies, including toxin-focused antibodies, toxin-based polymers, synbiotic agents, and secondary metabolites remedies. Besides, in recent years, antibiotics' efficacy in treating STEC infections has been reassessed with some encouraging methods. Nevertheless, the primary role of synbiotic effectiveness (probiotic and prebiotic) against pathogenic STEC and other enteropathogens is less recognized. Additional studies are required to understand the mechanisms of action of probiotic bacteria and yeast against STEC infection. Because of the consensus contraindication of antimicrobials for these bacterial pathogens, the examination was focused on alternative remedy strategies for STEC infections. The rise of novel STEC serotypes and approaches employed in its treatment are highlighted.
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Affiliation(s)
- Su-bin Hwang
- Department of Food Science and Biotechnology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Ramachandran Chelliah
- Department of Food Science and Biotechnology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Ji Eun Kang
- Department of Food Science and Biotechnology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Momna Rubab
- School of Food and Agricultural Sciences, University of Management and Technology, Lahore, Pakistan
| | - Eric Banan-MwineDaliri
- Department of Food Science and Biotechnology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Fazle Elahi
- Department of Food Science and Biotechnology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
| | - Deog-Hwan Oh
- Department of Food Science and Biotechnology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon, South Korea
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3
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Valid Presumption of Shiga Toxin-Mediated Damage of Developing Erythrocytes in EHEC-Associated Hemolytic Uremic Syndrome. Toxins (Basel) 2020; 12:toxins12060373. [PMID: 32512916 PMCID: PMC7354503 DOI: 10.3390/toxins12060373] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 02/06/2023] Open
Abstract
The global emergence of clinical diseases caused by enterohemorrhagic Escherichia coli (EHEC) is an issue of great concern. EHEC release Shiga toxins (Stxs) as their key virulence factors, and investigations on the cell-damaging mechanisms toward target cells are inevitable for the development of novel mitigation strategies. Stx-mediated hemolytic uremic syndrome (HUS), characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal injury, is the most severe outcome of an EHEC infection. Hemolytic anemia during HUS is defined as the loss of erythrocytes by mechanical disruption when passing through narrowed microvessels. The formation of thrombi in the microvasculature is considered an indirect effect of Stx-mediated injury mainly of the renal microvascular endothelial cells, resulting in obstructions of vessels. In this review, we summarize and discuss recent data providing evidence that HUS-associated hemolytic anemia may arise not only from intravascular rupture of erythrocytes, but also from the extravascular impairment of erythropoiesis, the development of red blood cells in the bone marrow, via direct Stx-mediated damage of maturing erythrocytes, leading to “non-hemolytic” anemia.
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4
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Lingwood C. Verotoxin Receptor-Based Pathology and Therapies. Front Cell Infect Microbiol 2020; 10:123. [PMID: 32296648 PMCID: PMC7136409 DOI: 10.3389/fcimb.2020.00123] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/05/2020] [Indexed: 12/22/2022] Open
Abstract
Verotoxin, VT (aka Shiga toxin,Stx) is produced by enterohemorrhagic E. coli (EHEC) and is the key pathogenic factor in EHEC-induced hemolytic uremic syndrome (eHUS-hemolytic anemia/thrombocytopenia/glomerular infarct) which can follow gastrointestinal EHEC infection, particularly in children. This AB5 subunit toxin family bind target cell globotriaosyl ceramide (Gb3), a glycosphingolipid (GSL) (aka CD77, pk blood group antigen) of the globoseries of neutral GSLs, initiating lipid raft-dependent plasma membrane Gb3 clustering, membrane curvature, invagination, scission, endosomal trafficking, and retrograde traffic via the TGN to the Golgi, and ER. In the ER, A/B subunits separate and the A subunit hijacks the ER reverse translocon (dislocon-used to eliminate misfolded proteins-ER associated degradation-ERAD) for cytosolic access. This property has been used to devise toxoid-based therapy to temporarily block ERAD and rescue the mutant phenotype of several genetic protein misfolding diseases. The A subunit avoids cytosolic proteosomal degradation, to block protein synthesis via its RNA glycanase activity. In humans, Gb3 is primarily expressed in the kidney, particularly in the glomerular endothelial cells. Here, Gb3 is in lipid rafts (more ordered membrane domains which accumulate GSLs/cholesterol) whereas renal tubular Gb3 is in the non-raft membrane fraction, explaining the basic pathology of eHUS (glomerular endothelial infarct). Females are more susceptible and this correlates with higher renal Gb3 expression. HUS can be associated with encephalopathy, more commonly following verotoxin 2 exposure. Gb3 is expressed in the microvasculature of the brain. All members of the VT family bind Gb3, but with varying affinity. VT2e (pig edema toxin) binds Gb4 preferentially. Verotoxin-specific therapeutics based on chemical analogs of Gb3, though effective in vitro, have failed in vivo. While some analogs are effective in animal models, there are no good rodent models of eHUS since Gb3 is not expressed in rodent glomeruli. However, the mouse mimics the neurological symptoms more closely and provides an excellent tool to assess therapeutics. In addition to direct cytotoxicity, other factors including VT–induced cytokine release and aberrant complement cascade, are now appreciated as important in eHUS. Based on atypical HUS therapy, treatment of eHUS patients with anticomplement antibodies has proven effective in some cases. A recent switch using stem cells to try to reverse, rather than prevent VT induced pathology may prove a more effective methodology.
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Affiliation(s)
- Clifford Lingwood
- Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
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5
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Pradhan S, Karve SS, Weiss AA, Hawkins J, Poling HM, Helmrath MA, Wells JM, McCauley HA. Tissue Responses to Shiga Toxin in Human Intestinal Organoids. Cell Mol Gastroenterol Hepatol 2020; 10:171-190. [PMID: 32145469 PMCID: PMC7240222 DOI: 10.1016/j.jcmgh.2020.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS Shiga toxin (Stx)-producing Escherichia coli (eg, O157:H7) infection produces bloody diarrhea, while Stx inhibits protein synthesis and causes the life-threatening systemic complication of hemolytic uremic syndrome. The murine intestinal tract is resistant to O157:H7 and Stx, and human cells in culture fail to model the complex tissue responses to intestinal injury. We used genetically identical, human stem cell-derived intestinal tissues of varying complexity to study Stx toxicity in vitro and in vivo. METHODS In vitro susceptibility to apical or basolateral exposure to Stx was assessed using human intestinal organoids (HIOs) derived from embryonic stem cells, or enteroids derived from multipotent intestinal stem cells. HIOs contain a lumen, with a single layer of differentiated epithelium surrounded by mesenchymal cells. Enteroids only contain epithelium. In vivo susceptibility was assessed using HIOs, with or without an enteric nervous system, transplanted into mice. RESULTS Stx induced necrosis and apoptotic death in both epithelial and mesenchymal cells. Responses that require protein synthesis (cellular proliferation and wound repair) also were observed. Epithelial barrier function was maintained even after epithelial cell death was seen, and apical to basolateral translocation of Stx was seen. Tissue cross-talk, in which mesenchymal cell damage caused epithelial cell damage, was observed. Stx induced mesenchymal expression of the epithelial marker E-cadherin, the initial step in mesenchymal-epithelial transition. In vivo responses of HIO transplants injected with Stx mirrored those seen in vitro. CONCLUSIONS Intestinal tissue responses to protein synthesis inhibition by Stx are complex. Organoid models allow for an unprecedented examination of human tissue responses to a deadly toxin.
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Affiliation(s)
- Suman Pradhan
- Department of Molecular Genetics, University of Cincinnati, Cincinnati, Ohio
| | - Sayali S Karve
- Department of Molecular Genetics, University of Cincinnati, Cincinnati, Ohio
| | - Alison A Weiss
- Department of Molecular Genetics, University of Cincinnati, Cincinnati, Ohio.
| | | | | | | | - James M Wells
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Heather A McCauley
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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6
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Structural and Functional Characterization of Stx2k, a New Subtype of Shiga Toxin 2. Microorganisms 2019; 8:microorganisms8010004. [PMID: 31861375 PMCID: PMC7022315 DOI: 10.3390/microorganisms8010004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 12/12/2019] [Accepted: 12/14/2019] [Indexed: 01/07/2023] Open
Abstract
Shiga toxin (Stx) is the major virulence factor of Shiga toxin-producing Escherichia coli (STEC). Stx evolves rapidly and, as such, new subtypes continue to emerge that challenge the efficacy of existing disease management and surveillance strategies. A new subtype, Stx2k, was recently identified in E. coli isolated from a wide range of sources including diarrheal patients, animals, and raw meats, and was poorly detected by existing immunoassays. In this study, the structure of Stx2kE167Q was determined at 2.29 Å resolution and the conservation of structure with Stx2a was revealed. A novel polyclonal antibody capable of neutralizing Stx2k and an immunoassay, with a 10-fold increase in sensitivity compared to assays using extant antibodies, were developed. Stx2k is less toxic than Stx2a in Vero cell assays but is similar to Stx2a in receptor-binding preference, thermostability, and acid tolerance. Although Stx2k does not appear to be as potent as Stx2a to Vero cells, the wide distribution and blended virulence profiles of the Stx2k-producing strains suggest that horizontal gene transfer through Stx2k-converting phages could result in the emergence of new and highly virulent pathogens. This study provides useful information and tools for early detection and control of Stx2k-producing E. coli, which could reduce public risk of infection by less-known STECs.
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7
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Legros N, Pohlentz G, Steil D, Müthing J. Shiga toxin-glycosphingolipid interaction: Status quo of research with focus on primary human brain and kidney endothelial cells. Int J Med Microbiol 2018; 308:1073-1084. [PMID: 30224239 DOI: 10.1016/j.ijmm.2018.09.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/28/2018] [Accepted: 09/06/2018] [Indexed: 12/21/2022] Open
Abstract
Shiga toxin (Stx)-mediated injury of the kidneys and the brain represent the major extraintestinal complications in humans upon infection by enterohemorrhagic Escherichia coli (EHEC). Damage of renal and cerebral endothelial cells is the key event in the pathogenesis of the life-threatening hemolytic uremic syndrome (HUS). Stxs are AB5 toxins and the B-pentamers of the two clinically important Stx subtypes Stx1a and Stx2a preferentially bind to the glycosphingolipid globotriaosylceramide (Gb3Cer, Galα4Galβ4Glcβ1Cer) and to less extent to globotetraosylceramide (Gb4Cer, GalNAcβ3Galα4Galβ4Glcβ1), which are expected to reside in lipid rafts in the plasma membrane of the human endothelium. This review summarizes the current knowledge on the Stx glycosphingolipid receptors and their lipid membrane ensemble in primary human brain microvascular endothelial cells (pHBMECs) and primary human renal glomerular endothelial cells (pHRGECs). Increasing knowledge on the precise initial molecular mechanisms by which Stxs interact with cellular targets will help to develop specific therapeutics and/or preventive measures to combat EHEC-caused diseases.
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Affiliation(s)
- Nadine Legros
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany
| | | | - Daniel Steil
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany
| | - Johannes Müthing
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany; Interdisciplinary Center for Clinical Research (IZKF), University of Münster, D-48149 Münster, Germany.
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8
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Silva CJ. Food Forensics: Using Mass Spectrometry To Detect Foodborne Protein Contaminants, as Exemplified by Shiga Toxin Variants and Prion Strains. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:8435-8450. [PMID: 29860833 DOI: 10.1021/acs.jafc.8b01517] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Food forensicists need a variety of tools to detect the many possible food contaminants. As a result of its analytical flexibility, mass spectrometry is one of those tools. Use of the multiple reaction monitoring (MRM) method expands its use to quantitation as well as detection of infectious proteins (prions) and protein toxins, such as Shiga toxins. The sample processing steps inactivate prions and Shiga toxins; the proteins are digested with proteases to yield peptides suitable for MRM-based analysis. Prions are detected by their distinct physicochemical properties and differential covalent modification. Shiga toxin analysis is based on detecting peptides derived from the five identical binding B subunits comprising the toxin. 15N-labeled internal standards are prepared from cloned proteins. These examples illustrate the power of MRM, in that the same instrument can be used to safely detect and quantitate protein toxins, prions, and small molecules that might contaminate our food.
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Affiliation(s)
- Christopher J Silva
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service , United States Department of Agriculture , Albany , California 94710 , United States
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9
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Moonens K, Remaut H. Evolution and structural dynamics of bacterial glycan binding adhesins. Curr Opin Struct Biol 2017; 44:48-58. [DOI: 10.1016/j.sbi.2016.12.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/30/2016] [Accepted: 12/05/2016] [Indexed: 01/25/2023]
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10
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Zhang P, Paszkiewicz E, Wang Q, Sadowska JM, Kitov PI, Bundle DR, Ling CC. Clustering of PK-trisaccharides on amphiphilic cyclodextrin reveals unprecedented affinity for the Shiga-like toxin Stx2. Chem Commun (Camb) 2017; 53:10528-10531. [DOI: 10.1039/c7cc06299k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Amphiphilic cyclodextrin-based PK-glycoarrays show remarkable binding avidity and selectivity for Stx2 in solid phase assay formats.
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Affiliation(s)
- Ping Zhang
- Alberta Glycomics Centre
- Department of Chemistry
- University of Calgary
- Calgary
- T2N 1N4 Canada
| | - Eugenia Paszkiewicz
- Alberta Glycomics Centre
- Department of Chemistry
- University of Alberta
- Edmonton
- T6G 2G2 Canada
| | - Qifang Wang
- Alberta Glycomics Centre
- Department of Chemistry
- University of Calgary
- Calgary
- T2N 1N4 Canada
| | - Joanna M. Sadowska
- Alberta Glycomics Centre
- Department of Chemistry
- University of Alberta
- Edmonton
- T6G 2G2 Canada
| | - Pavel I. Kitov
- Alberta Glycomics Centre
- Department of Chemistry
- University of Alberta
- Edmonton
- T6G 2G2 Canada
| | - David R. Bundle
- Alberta Glycomics Centre
- Department of Chemistry
- University of Alberta
- Edmonton
- T6G 2G2 Canada
| | - Chang-Chun Ling
- Alberta Glycomics Centre
- Department of Chemistry
- University of Calgary
- Calgary
- T2N 1N4 Canada
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11
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Ailte I, Lingelem ABD, Kavaliauskiene S, Bergan J, Kvalvaag AS, Myrann AG, Skotland T, Sandvig K. Addition of lysophospholipids with large head groups to cells inhibits Shiga toxin binding. Sci Rep 2016; 6:30336. [PMID: 27458147 PMCID: PMC4960542 DOI: 10.1038/srep30336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 06/30/2016] [Indexed: 12/20/2022] Open
Abstract
Shiga toxin (Stx), an AB5 toxin, binds specifically to the neutral glycosphingolipid Gb3 at the cell surface before being transported into cells. We here demonstrate that addition of conical lysophospholipids (LPLs) with large head groups inhibit Stx binding to cells whereas LPLs with small head groups do not. Lysophosphatidylinositol (LPI 18:0), the most efficient LPL with the largest head group, was selected for in-depth investigations to study how the binding of Stx is regulated. We show that the inhibition of Stx binding by LPI is reversible and possibly regulated by cholesterol since addition of methyl-β-cyclodextrin (mβCD) reversed the ability of LPI to inhibit binding. LPI-induced inhibition of Stx binding is independent of signalling and membrane turnover as it occurs in fixed cells as well as after depletion of cellular ATP. Furthermore, data obtained with fluorescent membrane dyes suggest that LPI treatment has a direct effect on plasma membrane lipid packing with shift towards a liquid disordered phase in the outer leaflet, while lysophosphoethanolamine (LPE), which has a small head group, does not. In conclusion, our data show that cellular treatment with conical LPLs with large head groups changes intrinsic properties of the plasma membrane and modulates Stx binding to Gb3.
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Affiliation(s)
- Ieva Ailte
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - Anne Berit Dyve Lingelem
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway
| | - Simona Kavaliauskiene
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - Jonas Bergan
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway.,Department of Research and Innovation, Østfold Hospital, Sarpsborg, Norway
| | - Audun Sverre Kvalvaag
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway
| | - Anne-Grethe Myrann
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway
| | - Tore Skotland
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway
| | - Kirsten Sandvig
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo, Norway.,Department of Biosciences, University of Oslo, Oslo, Norway
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12
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Bhatia S, Camacho LC, Haag R. Pathogen Inhibition by Multivalent Ligand Architectures. J Am Chem Soc 2016; 138:8654-66. [DOI: 10.1021/jacs.5b12950] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Sumati Bhatia
- Institut
für Chemie
und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
| | - Luis Cuellar Camacho
- Institut
für Chemie
und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
| | - Rainer Haag
- Institut
für Chemie
und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany
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13
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AB5 Preassembly Is Not Required for Shiga Toxin Activity. J Bacteriol 2016; 198:1621-1630. [PMID: 27002129 DOI: 10.1128/jb.00918-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 03/15/2016] [Indexed: 01/19/2023] Open
Abstract
UNLABELLED Shiga toxin (Stx)-producing Escherichia coli (STEC) is a major cause of foodborne illness, including the life-threatening complication hemolytic-uremic syndrome. The German outbreak in 2011 resulted in nearly 4,000 cases of infection, with 54 deaths. Two forms of Stx, Stx1 and Stx2, differ in potency, and subtype Stx2a is most commonly associated with fatal human disease. Stx is considered to be an AB5 toxin. The single A (enzymatically active) subunit inhibits protein synthesis by cleaving a catalytic adenine from the eukaryotic rRNA. The B (binding) subunit forms a homopentamer and mediates cellular association and toxin internalization by binding to the glycolipid globotriaosylceramide (Gb3). Both subunits are essential for toxicity. Here we report that unlike other AB5 toxin family members, Stx is produced by STEC as unassembled A and B subunits. A preformed AB5 complex is not required for cellular toxicity or in vivo toxicity to mice, and toxin assembly likely occurs at the cell membrane. We demonstrate that disruption of A- and B-subunit association by use of A-subunit peptides that lack enzymatic activity can protect mice from lethal doses of toxin. Currently, no treatments have been proven to be effective for hemolytic-uremic syndrome. Our studies demonstrate that agents that interfere with A- and B-subunit assembly may have therapeutic potential. Shiga toxin (Stx) produced by pathogenic Escherichia coli is considered to be an AB5 heterohexamer; however, no known mechanisms ensure AB5 assembly. Stx released by E. coli is not in the AB5 conformation and assembles at the receptor interface. Thus, unassembled Stx can impart toxicity. This finding shows that preventing AB5 assembly is a potential treatment for Stx-associated illnesses. IMPORTANCE Complications due to Shiga toxin are frequently fatal, and at present, supportive care is the only treatment option. Furthermore, antibiotic treatment is contraindicated due to the ability of antibiotics to amplify bacterial expression of Shiga toxin. We report, contrary to prevailing assumptions, that Shiga toxin produced by STEC circulates as unassembled A and B subunits at concentrations that are lethal to mice. Similar to the case for anthrax toxin, assembly occurs on receptors expressed on the surfaces of mammalian target cells. Disruption of Shiga toxin assembly by use of A-subunit peptides that lack enzymatic activity protects mice from lethal challenge with Shiga toxin, suggesting a new approach for development of therapeutics.
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14
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Shiga Toxins as Multi-Functional Proteins: Induction of Host Cellular Stress Responses, Role in Pathogenesis and Therapeutic Applications. Toxins (Basel) 2016; 8:toxins8030077. [PMID: 26999205 PMCID: PMC4810222 DOI: 10.3390/toxins8030077] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 02/25/2016] [Accepted: 02/29/2016] [Indexed: 12/17/2022] Open
Abstract
Shiga toxins (Stxs) produced by Shiga toxin-producing bacteria Shigella dysenteriae serotype 1 and select serotypes of Escherichia coli are primary virulence factors in the pathogenesis of hemorrhagic colitis progressing to potentially fatal systemic complications, such as hemolytic uremic syndrome and central nervous system abnormalities. Current therapeutic options to treat patients infected with toxin-producing bacteria are limited. The structures of Stxs, toxin-receptor binding, intracellular transport and the mode of action of the toxins have been well defined. However, in the last decade, numerous studies have demonstrated that in addition to being potent protein synthesis inhibitors, Stxs are also multifunctional proteins capable of activating multiple cell stress signaling pathways, which may result in apoptosis, autophagy or activation of the innate immune response. Here, we briefly present the current understanding of Stx-activated signaling pathways and provide a concise review of therapeutic applications to target tumors by engineering the toxins.
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15
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Hu Y, Tu YH, Liu DY, Liao JX, Sun JS. Synthetic investigation toward apigenin 5-O-glycoside camellianin B as well as the chemical structure revision. Org Biomol Chem 2016; 14:4842-7. [DOI: 10.1039/c6ob00655h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first total synthesis of the proposed and authentic structures of camellianin B were achieved, based on which the chemical structures of camellianins A and B were revised.
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Affiliation(s)
- Yang Hu
- The National Engineering Research Centre for Carbohydrate Synthesis
- Jiangxi Normal University
- Nanchang 330022
- China
| | - Yuan-Hong Tu
- The National Engineering Research Centre for Carbohydrate Synthesis
- Jiangxi Normal University
- Nanchang 330022
- China
| | - De-Yong Liu
- The National Engineering Research Centre for Carbohydrate Synthesis
- Jiangxi Normal University
- Nanchang 330022
- China
| | - Jin-Xi Liao
- The National Engineering Research Centre for Carbohydrate Synthesis
- Jiangxi Normal University
- Nanchang 330022
- China
| | - Jian-Song Sun
- The National Engineering Research Centre for Carbohydrate Synthesis
- Jiangxi Normal University
- Nanchang 330022
- China
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The Dramatic Modulatory Role of the 2'N Substitution of the Terminal Amino Hexose of Globotetraosylceramide in Determining Binding by Members of the Verotoxin Family. CHROMATOGRAPHY 2015. [DOI: 10.3390/chromatography2030529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Polymer antidotes for toxin sequestration. Adv Drug Deliv Rev 2015; 90:81-100. [PMID: 26026975 DOI: 10.1016/j.addr.2015.05.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/09/2015] [Accepted: 05/21/2015] [Indexed: 12/24/2022]
Abstract
Toxins delivered by envenomation, secreted by microorganisms, or unintentionally ingested can pose an immediate threat to life. Rapid intervention coupled with the appropriate antidote is required to mitigate the threat. Many antidotes are biological products and their cost, methods of production, potential for eliciting immunogenic responses, the time needed to generate them, and stability issues contribute to their limited availability and effectiveness. These factors exacerbate a world-wide challenge for providing treatment. In this review we evaluate a number of polymer constructs that may serve as alternative antidotes. The range of toxins investigated includes those from sources such as plants, animals and bacteria. The development of polymeric heavy metal sequestrants for use as antidotes to heavy metal poisoning faces similar challenges, thus recent findings in this area have also been included. Two general strategies have emerged for the development of polymeric antidotes. In one, the polymer acts as a scaffold for the presentation of ligands with a known affinity for the toxin. A second strategy is to generate polymers with an intrinsic affinity, and in some cases selectivity, to a range of toxins. Importantly, in vivo efficacy has been demonstrated for each of these strategies, which suggests that these approaches hold promise as an alternative to biological or small molecule based treatments.
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18
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El-Hawiet A, Kitova EN, Klassen JS. Recognition of human milk oligosaccharides by bacterial exotoxins. Glycobiology 2015; 25:845-54. [DOI: 10.1093/glycob/cwv025] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 04/22/2015] [Indexed: 01/09/2023] Open
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Basu D, Tumer NE. Do the A subunits contribute to the differences in the toxicity of Shiga toxin 1 and Shiga toxin 2? Toxins (Basel) 2015; 7:1467-85. [PMID: 25938272 PMCID: PMC4448158 DOI: 10.3390/toxins7051467] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/23/2015] [Accepted: 04/27/2015] [Indexed: 12/25/2022] Open
Abstract
Shiga toxin producing Escherichia coli O157:H7 (STEC) is one of the leading causes of food-poisoning around the world. Some STEC strains produce Shiga toxin 1 (Stx1) and/or Shiga toxin 2 (Stx2) or variants of either toxin, which are critical for the development of hemorrhagic colitis (HC) or hemolytic uremic syndrome (HUS). Currently, there are no therapeutic treatments for HC or HUS. E. coli O157:H7 strains carrying Stx2 are more virulent and are more frequently associated with HUS, which is the most common cause of renal failure in children in the US. The basis for the increased potency of Stx2 is not fully understood. Shiga toxins belong to the AB5 family of protein toxins with an A subunit, which depurinates a universally conserved adenine residue in the α-sarcin/ricin loop (SRL) of the 28S rRNA and five copies of the B subunit responsible for binding to cellular receptors. Recent studies showed differences in the structure, receptor binding, dependence on ribosomal proteins and pathogenicity of Stx1 and Stx2 and supported a role for the B subunit in differential toxicity. However, the current data do not rule out a potential role for the A1 subunits in the differential toxicity of Stx1 and Stx2. This review highlights the recent progress in understanding the differences in the A1 subunits of Stx1 and Stx2 and their role in defining toxicity.
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Affiliation(s)
- Debaleena Basu
- Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901-8520, USA.
| | - Nilgun E Tumer
- Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901-8520, USA.
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20
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Ruer S, Pinotsis N, Steadman D, Waksman G, Remaut H. Virulence-targeted Antibacterials: Concept, Promise, and Susceptibility to Resistance Mechanisms. Chem Biol Drug Des 2015; 86:379-99. [DOI: 10.1111/cbdd.12517] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/23/2014] [Accepted: 01/06/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Ségolène Ruer
- Structural and Molecular Microbiology; Structural Biology Research Center; VIB; Pleinlaan 2 Brussels 1050 Belgium
- Structural Biology Brussels; Vrije Universiteit Brussel; Pleinlaan 2 Brussels 1050 Belgium
| | - Nikos Pinotsis
- Institute of Structural and Molecular Biology (ISMB); UCL and Birkbeck College; London WC1E 7HX UK
| | - David Steadman
- Wolfson Institute for Biomedical Research (WIBR); UCL; London WC1E 6BT UK
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology (ISMB); UCL and Birkbeck College; London WC1E 7HX UK
| | - Han Remaut
- Structural and Molecular Microbiology; Structural Biology Research Center; VIB; Pleinlaan 2 Brussels 1050 Belgium
- Structural Biology Brussels; Vrije Universiteit Brussel; Pleinlaan 2 Brussels 1050 Belgium
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21
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Karve SS, Weiss AA. Glycolipid binding preferences of Shiga toxin variants. PLoS One 2014; 9:e101173. [PMID: 24983355 PMCID: PMC4077739 DOI: 10.1371/journal.pone.0101173] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 06/03/2014] [Indexed: 11/18/2022] Open
Abstract
The major virulence factor of Shiga toxin producing E. coli, is Shiga toxin (Stx), an AB5 toxin that consists of a ribosomal RNA-cleaving A-subunit surrounded by a pentamer of receptor-binding B subunits. The two major isoforms, Stx1 and Stx2, and Stx2 variants (Stx2a-h) significantly differ in toxicity. The exact reason for this toxicity difference is unknown, however different receptor binding preferences are speculated to play a role. Previous studies used enzyme linked immunosorbent assay (ELISA) to study binding of Stx1 and Stx2a toxoids to glycolipid receptors. Here, we studied binding of holotoxin and B-subunits of Stx1, Stx2a, Stx2b, Stx2c and Stx2d to glycolipid receptors globotriaosylceramide (Gb3) and globotetraosylceramide (Gb4) in the presence of cell membrane components such as phosphatidylcholine (PC), cholesterol (Ch) and other neutral glycolipids. In the absence of PC and Ch, holotoxins of Stx2 variants bound to mixtures of Gb3 with other glycolipids but not to Gb3 or Gb4 alone. Binding of all Stx holotoxins significantly increased in the presence of PC and Ch. Previously, Stx2a has been shown to form a less stable B-pentamer compared to Stx1. However, its effect on glycolipid receptor binding is unknown. In this study, we showed that even in the absence of the A-subunit, the B-subunits of both Stx1 and Stx2a were able to bind to the glycolipids and the more stable B-pentamer formed by Stx1 bound better than the less stable pentamer of Stx2a. B-subunit mutant of Stx1 L41Q, which shows similar stability as Stx2a B-subunits, lacked glycolipid binding, suggesting that pentamerization is more critical for binding of Stx1 than Stx2a.
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Affiliation(s)
- Sayali S. Karve
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Alison A. Weiss
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio, United States of America
- * E-mail:
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