1
|
Felegary A, Nazarian S, Zafarmand-Samarin M, Sadeghi D, Fathi J, Samiei-Abianeh H. Evaluation of the prophylactic effect of egg yolk antibody (IgY) produced against the recombinant protein containing IpaD, IpaB, StxB, and VirG proteins from Shigella. Mol Immunol 2024; 173:53-60. [PMID: 39053389 DOI: 10.1016/j.molimm.2024.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/03/2024] [Accepted: 07/07/2024] [Indexed: 07/27/2024]
Abstract
INTRODUCTION Shigellosis is a gastrointestinal disease causes high morbidity and mortality worldwide, however, there is no anti-Shigella vaccine. The use of antibiotics in shigellosis treatment exacerbates antibiotic resistance. Antibodies, particularly egg yolk antibody (IgY), offer a promising approach to address this challenge. This study aimed to investigate the prophylactic effect of IgY produced against a recombinant chimeric protein containing the immunogens IpaD, IpaB, StxB, and VirG from Shigella. METHODS The chimeric protein, comprising IpaD, IpaB, StxB, and VirG, was expressed in E. coli BL21 and purified using the Ni-NTA column. Following immunization of chickens, IgY was extracted from egg yolk using the PEG-6000 method and analyzed through SDS-PAGE and ELISA techniques. Subsequently, the prophylactic efficacy of IgY was assessed by challenging of mice with 10 LD50 of S. dysenteriae and administering different concentrations of IgY (1.25, 2.5, 5, and 10 mg/kg) under various time conditions. RESULTS The recombinant protein, weighing 82 kDa, was purified and confirmed by western blotting. The IgY concentration was determined as 9.5 mg/ml of egg yolk and the purity of the extracted IgY was over 90 %. The results of the ELISA showed that at least 19 ng of pure antibody identified recombinant protein and reacts with it. The challenge test employing IgY and Shigella demonstrated a direct correlation between the survival rate and antibody concentration, with increased concentrations leading to decreased mortality rates. Treatment of mice with 10 mg/kg IgY leads to 80 % survival of the mice against 10 LD50 S. dysenteriae. CONCLUSION Our findings suggest that IgY may offer therapeutic potential in treating Shigella infections and combating antibiotic resistance.
Collapse
Affiliation(s)
- Alireza Felegary
- Department of Biology, Faculty of Basic Sciences, Imam Hossein University, Tehran, Iran
| | - Shahram Nazarian
- Department of Biology, Faculty of Basic Sciences, Imam Hossein University, Tehran, Iran.
| | | | - Davoud Sadeghi
- Department of Biology, Faculty of Basic Sciences, Imam Hossein University, Tehran, Iran.
| | - Javad Fathi
- Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hossein Samiei-Abianeh
- Department of Biology, Faculty of Basic Sciences, Imam Hossein University, Tehran, Iran; Department of Medical Biotechnology and Nanotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| |
Collapse
|
2
|
Müller T, Krieg N, Lange-Polovinkin AI, Wissuwa B, Gräler MH, Dennhardt S, Coldewey SM. Deletion of Sphingosine Kinase 2 Attenuates Acute Kidney Injury in Mice with Hemolytic-Uremic Syndrome. Int J Mol Sci 2024; 25:7683. [PMID: 39062926 PMCID: PMC11277509 DOI: 10.3390/ijms25147683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 07/09/2024] [Accepted: 07/10/2024] [Indexed: 07/28/2024] Open
Abstract
Typical hemolytic uremic syndrome (HUS) can occur as a severe systemic complication of infections with Shiga toxin (Stx)-producing Escherichia coli. Its pathology can be induced by Stx types, resulting in toxin-mediated damage to renal barriers, inflammation, and the development of acute kidney injury (AKI). Two sphingosine kinase (SphK) isozymes, SphK1 and SphK2, have been shown to be involved in barrier maintenance and renal inflammatory diseases. Therefore, we sought to determine their role in the pathogenesis of HUS. Experimental HUS was induced by the repeated administration of Stx2 in wild-type (WT) and SphK1 (SphK1-/-) or SphK2 (SphK2-/-) null mutant mice. Disease severity was evaluated by assessing clinical symptoms, renal injury and dysfunction, inflammatory status and sphingolipid levels on day 5 of HUS development. Renal inflammation and injury were found to be attenuated in the SphK2-/- mice, but exacerbated in the SphK1-/- mice compared to the WT mice. The divergent outcome appeared to be associated with oppositely altered sphingolipid levels. This study represents the first description of the distinct roles of SphK1-/- and SphK2-/- in the pathogenesis of HUS. The identification of sphingolipid metabolism as a potential target for HUS therapy represents a significant advance in the field of HUS research.
Collapse
Affiliation(s)
- Tina Müller
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07743 Jena, Germany; (T.M.); (N.K.)
- ZIK Septomics Research Center, Jena University Hospital, 07743 Jena, Germany
| | - Nadine Krieg
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07743 Jena, Germany; (T.M.); (N.K.)
- ZIK Septomics Research Center, Jena University Hospital, 07743 Jena, Germany
| | - Antonia I. Lange-Polovinkin
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07743 Jena, Germany; (T.M.); (N.K.)
- ZIK Septomics Research Center, Jena University Hospital, 07743 Jena, Germany
| | - Bianka Wissuwa
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07743 Jena, Germany; (T.M.); (N.K.)
- ZIK Septomics Research Center, Jena University Hospital, 07743 Jena, Germany
| | - Markus H. Gräler
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07743 Jena, Germany; (T.M.); (N.K.)
- Center for Molecular Biomedicine (CMB) and Center for Sepsis Control and Care (CSCC), Jena University Hospital, 07743 Jena, Germany
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, 07743 Jena, Germany
| | - Sophie Dennhardt
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07743 Jena, Germany; (T.M.); (N.K.)
- ZIK Septomics Research Center, Jena University Hospital, 07743 Jena, Germany
| | - Sina M. Coldewey
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07743 Jena, Germany; (T.M.); (N.K.)
- ZIK Septomics Research Center, Jena University Hospital, 07743 Jena, Germany
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, 07743 Jena, Germany
| |
Collapse
|
3
|
Garofalo M, Payros D, Taieb F, Oswald E, Nougayrède JP, Oswald IP. From ribosome to ribotoxins: understanding the toxicity of deoxynivalenol and Shiga toxin, two food borne toxins. Crit Rev Food Sci Nutr 2023:1-13. [PMID: 37862145 DOI: 10.1080/10408398.2023.2271101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Abstract
Ribosomes that synthesize proteins are among the most central and evolutionarily conserved organelles. Given the key role of proteins in cellular functions, prokaryotic and eukaryotic pathogens have evolved potent toxins to inhibit ribosomal functions and weaken their host. Many of these ribotoxin-producing pathogens are associated with food. For example, food can be contaminated with bacterial pathogens that produce the ribotoxin Shiga toxin, but also with the fungal ribotoxin deoxynivalenol. Shiga toxin cleaves ribosomal RNA, while deoxynivalenol binds to and inhibits the peptidyl transferase center. Despite their distinct modes of action, both groups of ribotoxins hinder protein translation, but also trigger other comparable toxic effects, which depend or not on the activation of the ribotoxic stress response. Ribotoxic stress response-dependent effects include inflammation and apoptosis, whereas ribotoxic stress response-independent effects include endoplasmic reticulum stress, oxidative stress, and autophagy. For other effects, such as cell cycle arrest and cytoskeleton modulation, the involvement of the ribotoxic stress response is still controversial. Ribotoxins affect one organelle yet induce multiple toxic effects with multiple consequences for the cell. The ribosome can therefore be considered as the cellular "Achilles heel" targeted by food borne ribotoxins. Considering the high toxicity of ribotoxins, they pose a substantial health risk, as humans are highly susceptible to widespread exposure to these toxins through contaminated food sources.
Collapse
Affiliation(s)
- Marion Garofalo
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
| | - Delphine Payros
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
| | - Frederic Taieb
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
| | - Eric Oswald
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
- CHU Toulouse, Hôpital Purpan, Toulouse, France
| | | | - Isabelle P Oswald
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| |
Collapse
|
4
|
Kellnerová S, Huber S, Massri M, Fleischer V, Losso K, Sarg B, Kremser L, Talasz H, He X, Varrone E, Brigotti M, Ardissino G, Orth-Höller D, Würzner R. Enzymatic Cleavage of Stx2a in the Gut and Identification of Pancreatic Elastase and Trypsin as Possible Main Cleavers. Microorganisms 2023; 11:2487. [PMID: 37894145 PMCID: PMC10609011 DOI: 10.3390/microorganisms11102487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/15/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023] Open
Abstract
Shiga toxins (Stxs), especially the Stx2a subtype, are the major virulence factors involved in enterohemorrhagic Escherichia coli (EHEC)-associated hemolytic uremic syndrome (eHUS), a life-threatening disease causing acute kidney injury, especially in children. After oral transmission and colonization in the gut, EHEC release Stx. Intracellular cleavage of the Stx A subunit, when followed by reduction, boosts the enzymatic activity that causes damage to targeted cells. This cleavage was assumed to be mostly mediated by furin during Stx intracellular trafficking. To investigate whether this cleavage could occur in the intestine, even prior to entering target cells, Stx2a A subunit structure (intact or cleaved) was characterized after its exposure to specific host factors present in human stool. The molecular weight of Stx2a A subunit/fragments was determined by immunoblotting after electrophoretic separation under reducing conditions. In this study, it was demonstrated that Stx2a is cleaved by certain human stool components. Trypsin and chymotrypsin-like elastase 3B (CELA3B), two serine proteases, were identified as potential candidates that can trigger the extracellular cleavage of Stx2a A subunit directly after its secretion by EHEC in the gut. Whether the observed cleavage indeed translates to natural infections and plays a role in eHUS pathogenesis has yet to be determined. If so, it seems likely that a host's protease profile could affect disease development by changing the toxin's biological features.
Collapse
Affiliation(s)
- Sára Kellnerová
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.K.); (S.H.); (M.M.); (V.F.)
| | - Silke Huber
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.K.); (S.H.); (M.M.); (V.F.)
| | - Mariam Massri
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.K.); (S.H.); (M.M.); (V.F.)
| | - Verena Fleischer
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.K.); (S.H.); (M.M.); (V.F.)
| | - Klemens Losso
- Institute of Analytical Chemistry and Radiochemistry, University of Innsbruck, 6020 Innsbruck, Austria;
- Department of Food Technology and Nutrition, MCI|The Entrepreneurial School, 6020 Innsbruck, Austria
| | - Bettina Sarg
- Protein Core Facility, Institute of Medical Biochemistry, Center of Chemistry and Biomedicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (B.S.); (L.K.); (H.T.)
| | - Leopold Kremser
- Protein Core Facility, Institute of Medical Biochemistry, Center of Chemistry and Biomedicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (B.S.); (L.K.); (H.T.)
| | - Heribert Talasz
- Protein Core Facility, Institute of Medical Biochemistry, Center of Chemistry and Biomedicine, Medical University of Innsbruck, 6020 Innsbruck, Austria; (B.S.); (L.K.); (H.T.)
| | - Xiaohua He
- Western Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Albany, CA 74710, USA;
| | - Elisa Varrone
- Department of Medical and Surgical Sciences, School of Medicine, University of Bologna, 40126 Bologna, Italy; (E.V.); (M.B.)
| | - Maurizio Brigotti
- Department of Medical and Surgical Sciences, School of Medicine, University of Bologna, 40126 Bologna, Italy; (E.V.); (M.B.)
| | - Gianluigi Ardissino
- Center for HUS Prevention, Control and Management at Pediatric Nephrology, Dialysis and Transplant Unit, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy;
| | - Dorothea Orth-Höller
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.K.); (S.H.); (M.M.); (V.F.)
- MB-LAB–Clinical Microbiology Laboratory, 6020 Innsbruck, Austria
| | - Reinhard Würzner
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (S.K.); (S.H.); (M.M.); (V.F.)
| |
Collapse
|
5
|
Zhang X, Payne M, Kaur S, Lan R. Improved Genomic Identification, Clustering, and Serotyping of Shiga Toxin-Producing Escherichia coli Using Cluster/Serotype-Specific Gene Markers. Front Cell Infect Microbiol 2022; 11:772574. [PMID: 35083165 PMCID: PMC8785982 DOI: 10.3389/fcimb.2021.772574] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/03/2021] [Indexed: 11/16/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) have more than 470 serotypes. The well-known STEC O157:H7 serotype is a leading cause of STEC infections in humans. However, the incidence of non-O157:H7 STEC serotypes associated with foodborne outbreaks and human infections has increased in recent years. Current detection and serotyping assays are focusing on O157 and top six (“Big six”) non-O157 STEC serogroups. In this study, we performed phylogenetic analysis of nearly 41,000 publicly available STEC genomes representing 460 different STEC serotypes and identified 19 major and 229 minor STEC clusters. STEC cluster-specific gene markers were then identified through comparative genomic analysis. We further identified serotype-specific gene markers for the top 10 most frequent non-O157:H7 STEC serotypes. The cluster or serotype specific gene markers had 99.54% accuracy and more than 97.25% specificity when tested using 38,534 STEC and 14,216 non-STEC E. coli genomes, respectively. In addition, we developed a freely available in silico serotyping pipeline named STECFinder that combined these robust gene markers with established E. coli serotype specific O and H antigen genes and stx genes for accurate identification, cluster determination and serotyping of STEC. STECFinder can assign 99.85% and 99.83% of 38,534 STEC isolates to STEC clusters using assembled genomes and Illumina reads respectively and can simultaneously predict stx subtypes and STEC serotypes. Using shotgun metagenomic sequencing reads of STEC spiked food samples from a published study, we demonstrated that STECFinder can detect the spiked STEC serotypes, accurately. The cluster/serotype-specific gene markers could also be adapted for culture independent typing, facilitating rapid STEC typing. STECFinder is available as an installable package (https://github.com/LanLab/STECFinder) and will be useful for in silico STEC cluster identification and serotyping using genome data.
Collapse
Affiliation(s)
- Xiaomei Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Michael Payne
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Sandeep Kaur
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Ruiting Lan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| |
Collapse
|
6
|
Shiga Toxins as Antitumor Tools. Toxins (Basel) 2021; 13:toxins13100690. [PMID: 34678982 PMCID: PMC8538568 DOI: 10.3390/toxins13100690] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/12/2021] [Accepted: 09/22/2021] [Indexed: 11/16/2022] Open
Abstract
Shiga toxins (Stxs), also known as Shiga-like toxins (SLT) or verotoxins (VT), constitute a family of structurally and functionally related cytotoxic proteins produced by the enteric pathogens Shigella dysenteriae type 1 and Stx-producing Escherichia coli (STEC). Infection with these bacteria causes bloody diarrhea and other pathological manifestations that can lead to HUS (hemolytic and uremic syndrome). At the cellular level, Stxs bind to the cellular receptor Gb3 and inhibit protein synthesis by removing an adenine from the 28S rRNA. This triggers multiple cellular signaling pathways, including the ribotoxic stress response (RSR), unfolded protein response (UPR), autophagy and apoptosis. Stxs cause several pathologies of major public health concern, but their specific targeting of host cells and efficient delivery to the cytosol could potentially be exploited for biomedical purposes. Moreover, high levels of expression have been reported for the Stxs receptor, Gb3/CD77, in Burkitt's lymphoma (BL) cells and on various types of solid tumors. These properties have led to many attempts to develop Stxs as tools for biomedical applications, such as cancer treatment or imaging, and several engineered Stxs are currently being tested. We provide here an overview of these studies.
Collapse
|
7
|
Detzner J, Klein AL, Pohlentz G, Krojnewski E, Humpf HU, Mellmann A, Karch H, Müthing J. Primary Human Renal Proximal Tubular Epithelial Cells (pHRPTEpiCs): Shiga Toxin (Stx) Glycosphingolipid Receptors, Stx Susceptibility, and Interaction with Membrane Microdomains. Toxins (Basel) 2021; 13:toxins13080529. [PMID: 34437399 PMCID: PMC8402424 DOI: 10.3390/toxins13080529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/20/2021] [Accepted: 07/23/2021] [Indexed: 12/13/2022] Open
Abstract
Tubular epithelial cells of the human kidney are considered as targets of Shiga toxins (Stxs) in the Stx-mediated pathogenesis of hemolytic–uremic syndrome (HUS) caused by Stx-releasing enterohemorrhagic Escherichia coli (EHEC). Analysis of Stx-binding glycosphingolipids (GSLs) of primary human renal proximal tubular epithelial cells (pHRPTEpiCs) yielded globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer) with Cer (d18:1, C16:0), Cer (d18:1, C22:0), and Cer (d18:1, C24:1/C24:0) as the dominant lipoforms. Investigation of detergent-resistant membranes (DRMs) and nonDRMs, serving as equivalents for the liquid-ordered and liquid-disordered membrane phase, respectively, revealed the prevalence of Gb3Cer and Gb4Cer together with cholesterol and sphingomyelin in DRMs, suggesting lipid raft association. Stx1a and Stx2a exerted strong cellular damage with half-maximal cytotoxic doses (CD50) of 1.31 × 102 pg/mL and 1.66 × 103 pg/mL, respectively, indicating one order of magnitude higher cellular cytotoxicity of Stx1a. Surface acoustic wave (SAW) real-time interaction analysis using biosensor surfaces coated with DRM or nonDRM fractions gave stronger binding capability of Stx1a versus Stx2a that correlated with the lower cytotoxicity of Stx2a. Our study underlines the substantial role of proximal tubular epithelial cells of the human kidney being associated with the development of Stx-mediated HUS at least for Stx1a, while the impact of Stx2a remains somewhat ambiguous.
Collapse
Affiliation(s)
- Johanna Detzner
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (A.-L.K.); (G.P.); (E.K.); (A.M.); (H.K.)
| | - Anna-Lena Klein
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (A.-L.K.); (G.P.); (E.K.); (A.M.); (H.K.)
| | - Gottfried Pohlentz
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (A.-L.K.); (G.P.); (E.K.); (A.M.); (H.K.)
| | - Elisabeth Krojnewski
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (A.-L.K.); (G.P.); (E.K.); (A.M.); (H.K.)
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, University of Münster, D-48149 Münster, Germany;
| | - Alexander Mellmann
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (A.-L.K.); (G.P.); (E.K.); (A.M.); (H.K.)
| | - Helge Karch
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (A.-L.K.); (G.P.); (E.K.); (A.M.); (H.K.)
| | - Johannes Müthing
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (A.-L.K.); (G.P.); (E.K.); (A.M.); (H.K.)
- Correspondence:
| |
Collapse
|
8
|
Detzner J, Krojnewski E, Pohlentz G, Steil D, Humpf HU, Mellmann A, Karch H, Müthing J. Shiga Toxin (Stx)-Binding Glycosphingolipids of Primary Human Renal Cortical Epithelial Cells (pHRCEpiCs) and Stx-Mediated Cytotoxicity. Toxins (Basel) 2021; 13:toxins13020139. [PMID: 33673393 PMCID: PMC7918848 DOI: 10.3390/toxins13020139] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 12/12/2022] Open
Abstract
Human kidney epithelial cells are supposed to be directly involved in the pathogenesis of the hemolytic–uremic syndrome (HUS) caused by Shiga toxin (Stx)-producing enterohemorrhagic Escherichia coli (EHEC). The characterization of the major and minor Stx-binding glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer), respectively, of primary human renal cortical epithelial cells (pHRCEpiCs) revealed GSLs with Cer (d18:1, C16:0), Cer (d18:1, C22:0), and Cer (d18:1, C24:1/C24:0) as the dominant lipoforms. Using detergent-resistant membranes (DRMs) and non-DRMs, Gb3Cer and Gb4Cer prevailed in the DRM fractions, suggesting their association with microdomains in the liquid-ordered membrane phase. A preference of Gb3Cer and Gb4Cer endowed with C24:0 fatty acid accompanied by minor monounsaturated C24:1-harboring counterparts was observed in DRMs, whereas the C24:1 fatty acid increased in relation to the saturated equivalents in non-DRMs. A shift of the dominant phospholipid phosphatidylcholine with saturated fatty acids in the DRM to unsaturated species in the non-DRM fractions correlated with the GSL distribution. Cytotoxicity assays gave a moderate susceptibility of pHRCEpiCs to the Stx1a and Stx2a subtypes when compared to highly sensitive Vero-B4 cells. The results indicate that presence of Stx-binding GSLs per se and preferred occurrence in microdomains do not necessarily lead to a high cellular susceptibility towards Stx.
Collapse
Affiliation(s)
- Johanna Detzner
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (E.K.); (G.P.); (D.S.); (A.M.); (H.K.)
| | - Elisabeth Krojnewski
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (E.K.); (G.P.); (D.S.); (A.M.); (H.K.)
| | - Gottfried Pohlentz
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (E.K.); (G.P.); (D.S.); (A.M.); (H.K.)
| | - Daniel Steil
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (E.K.); (G.P.); (D.S.); (A.M.); (H.K.)
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, University of Münster, D-48149 Münster, Germany;
| | - Alexander Mellmann
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (E.K.); (G.P.); (D.S.); (A.M.); (H.K.)
| | - Helge Karch
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (E.K.); (G.P.); (D.S.); (A.M.); (H.K.)
| | - Johannes Müthing
- Institute of Hygiene, University of Münster, D-48149 Münster, Germany; (J.D.); (E.K.); (G.P.); (D.S.); (A.M.); (H.K.)
- Correspondence:
| |
Collapse
|
9
|
Shiga Toxin 2a Binds to Complement Components C3b and C5 and Upregulates Their Gene Expression in Human Cell Lines. Toxins (Basel) 2020; 13:toxins13010008. [PMID: 33374102 PMCID: PMC7824702 DOI: 10.3390/toxins13010008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/16/2020] [Accepted: 12/22/2020] [Indexed: 01/06/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) infections can cause EHEC-associated hemolytic uremic syndrome (eHUS) via its main virulent factor, Shiga toxins (Stxs). Complement has been reported to be involved in the progression of eHUS. The aim of this study was to investigate the interactions of the most effective subtype of the toxin, Stx2a, with pivotal complement proteins C3b and C5. The study further examined the effect of Stx2a stimulation on the transcription and synthesis of these complement proteins in human target cell lines. Binding of Stx2a to C3b and C5 was evaluated by ELISA. Kidney and gut cell lines (HK-2 and HCT-8) were stimulated with varied concentrations of Stx2a. Subsequent evaluation of complement gene transcription was studied by real-time PCR (qPCR), and ELISAs and Western blots were performed to examine protein synthesis of C3 and C5 in supernatants and lysates of stimulated HK-2 cells. Stx2a showed a specific binding to C3b and C5. Gene transcription of C3 and C5 was upregulated with increasing concentrations of Stx2a in both cell lines, but protein synthesis was not. This study demonstrates the binding of Stx2a to complement proteins C3b and C5, which could potentially be involved in regulating complement during eHUS infection, supporting further investigations into elucidating the role of complement in eHUS pathogenesis.
Collapse
|
10
|
Lee KS, Lee J, Lee P, Kim CU, Kim DJ, Jeong YJ, Park YJ, Tesh VL, Lee MS. Exosomes released from Shiga toxin 2a-treated human macrophages modulate inflammatory responses and induce cell death in toxin receptor expressing human cells. Cell Microbiol 2020; 22:e13249. [PMID: 32772454 DOI: 10.1111/cmi.13249] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 07/02/2020] [Accepted: 07/24/2020] [Indexed: 12/13/2022]
Abstract
Shiga toxins (Stxs) produced by Stx-producing Escherichia coli are the primarily virulence factors of hemolytic uremic syndrome and central nervous system (CNS) impairment. Although the precise mechanisms of toxin dissemination remain unclear, Stxs bind to extracellular vesicles (EVs). Exosomes, a subset of EVs, may play a key role in Stx-mediated renal injury. To test this hypothesis, we isolated exosomes from monocyte-derived macrophages in the presence of Stx2a or Stx2 toxoids. Macrophage-like differentiated THP-1 cells treated with Stxs secreted Stx-associated exosomes (Stx-Exo) of 90-130 nm in diameter, which induced cytotoxicity in recipient cells in a toxin receptor globotriaosylceramide (Gb3 )-dependent manner. Stx2-Exo engulfed by Gb3 -positive cells were translocated to the endoplasmic reticulum in the human proximal tubule epithelial cell line HK-2. Stx2-Exo contained pro-inflammatory cytokine mRNAs and proteins and induced more severe inflammation than purified Stx2a accompanied by greater death of target cells such as human renal or retinal pigment epithelial cells. Blockade of exosome biogenesis using the pharmacological inhibitor GW4869 reduced Stx2-Exo-mediated human renal cell death. Stx2-Exo isolated from human primary monocyte-derived macrophages activated caspase 3/7 and resulted in significant cell death in primary human renal cortical epithelial cells. Based on these results, we speculate that Stx-containing exosomes derived from macrophages may exacerbate cytotoxicity and inflammation and trigger cell death in toxin-sensitive cells. Therapeutic interventions targeting Stx-containing exosomes may prevent or ameliorate Stx-mediated acute vascular dysfunction.
Collapse
Affiliation(s)
- Kyung-Soo Lee
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, South Korea
| | - Jieun Lee
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Pureum Lee
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, South Korea
| | - Chang-Ung Kim
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Doo-Jin Kim
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Yu-Jin Jeong
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Young-Jun Park
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, South Korea
| | - Vernon L Tesh
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College of Medicine, Bryan, Texas, USA
| | - Moo-Seung Lee
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, South Korea
| |
Collapse
|
11
|
Kim JS, Lee MS, Kim JH. Recent Updates on Outbreaks of Shiga Toxin-Producing Escherichia coli and Its Potential Reservoirs. Front Cell Infect Microbiol 2020; 10:273. [PMID: 32582571 PMCID: PMC7287036 DOI: 10.3389/fcimb.2020.00273] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 05/07/2020] [Indexed: 12/30/2022] Open
Abstract
Following infection with certain strains of Shiga toxin-producing Escherichia coli (STEC), particularly enterohemorrhagic ones, patients are at elevated risk for developing life-threatening extraintestinal complications, such as acute renal failure. Hence, these bacteria represent a public health concern in both developed and developing countries. Shiga toxins (Stxs) expressed by STEC are highly cytotoxic class II ribosome-inactivating proteins and primary virulence factors responsible for major clinical signs of Stx-mediated pathogenesis, including bloody diarrhea, hemolytic uremic syndrome (HUS), and neurological complications. Ruminant animals are thought to serve as critical environmental reservoirs of Stx-producing Escherichia coli (STEC), but other emerging or arising reservoirs of the toxin-producing bacteria have been overlooked. In particular, a number of new animal species from wildlife and aquaculture industries have recently been identified as unexpected reservoir or spillover hosts of STEC. Here, we summarize recent findings about reservoirs of STEC and review outbreaks of these bacteria both within and outside the United States. A better understanding of environmental transmission to humans will facilitate the development of novel strategies for preventing zoonotic STEC infection.
Collapse
Affiliation(s)
- Jun-Seob Kim
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Moo-Seung Lee
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, South Korea.,Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Ji Hyung Kim
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, South Korea
| |
Collapse
|
12
|
Molecular Biology of Escherichia Coli Shiga Toxins' Effects on Mammalian Cells. Toxins (Basel) 2020; 12:toxins12050345. [PMID: 32456125 PMCID: PMC7290813 DOI: 10.3390/toxins12050345] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/18/2020] [Accepted: 05/20/2020] [Indexed: 12/11/2022] Open
Abstract
Shiga toxins (Stxs), syn. Vero(cyto)toxins, are potent bacterial exotoxins and the principal virulence factor of enterohemorrhagic Escherichia coli (EHEC), a subset of Shiga toxin-producing E. coli (STEC). EHEC strains, e.g., strains of serovars O157:H7 and O104:H4, may cause individual cases as well as large outbreaks of life-threatening diseases in humans. Stxs primarily exert a ribotoxic activity in the eukaryotic target cells of the mammalian host resulting in rapid protein synthesis inhibition and cell death. Damage of endothelial cells in the kidneys and the central nervous system by Stxs is central in the pathogenesis of hemolytic uremic syndrome (HUS) in humans and edema disease in pigs. Probably even more important, the toxins also are capable of modulating a plethora of essential cellular functions, which eventually disturb intercellular communication. The review aims at providing a comprehensive overview of the current knowledge of the time course and the consecutive steps of Stx/cell interactions at the molecular level. Intervention measures deduced from an in-depth understanding of this molecular interplay may foster our basic understanding of cellular biology and microbial pathogenesis and pave the way to the creation of host-directed active compounds to mitigate the pathological conditions of STEC infections in the mammalian body.
Collapse
|
13
|
Shimizu M. Pathogenic functions and diagnostic utility of cytokines/chemokines in EHEC-HUS. Pediatr Int 2020; 62:308-315. [PMID: 31742829 DOI: 10.1111/ped.14053] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/07/2019] [Accepted: 11/15/2019] [Indexed: 12/13/2022]
Abstract
Hemolytic - uremic syndrome (HUS) is a severe complication of infection by Shiga toxin (STx)-producing enterohemorrhagic Escherichia coli. Hemolytic - uremic syndrome is defined clinically as a triad of non-immune microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injuries. Neurologic complications such as acute encephalopathy are also observed. In humans, endothelial cells, proximal tubular epithelial cells, mesangial cells, podocytes, intestinal epithelial cells, and monocytes / macrophages are susceptible to STx-mediated injury. Shiga toxin induces the secretion of inflammatory cytokines and chemokines from susceptible cells, including tumor necrosis factor-α interleukin (IL)-1, IL-6, and IL-8. These cytokines and chemokines contribute to the pathogenesis of HUS and encephalopathy by enhancing STx-induced cytotoxicity and inducing inflammatory cell infiltration. Serum cytokine/chemokine levels are therefore useful as indicators of disease activity and predictors of progression from acute kidney injury to chronic kidney disease. Anti-inflammation therapy combined with apheresis to remove excessive cytokines / chemokines and methylprednisolone pulse therapy to suppress cytokine/chemokine production may be an effective treatment regimen for severe E. coli-associated HUS. However, this regimen requires careful monitoring of potential side effects, such as infections, thrombus formation, and hypertension.
Collapse
Affiliation(s)
- Masaki Shimizu
- Department of Pediatrics, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| |
Collapse
|
14
|
Detzner J, Gloerfeld C, Pohlentz G, Legros N, Humpf HU, Mellmann A, Karch H, Müthing J. Structural Insights into Escherichia coli Shiga Toxin (Stx) Glycosphingolipid Receptors of Porcine Renal Epithelial Cells and Inhibition of Stx-Mediated Cellular Injury Using Neoglycolipid-Spiked Glycovesicles. Microorganisms 2019; 7:microorganisms7110582. [PMID: 31752441 PMCID: PMC6920957 DOI: 10.3390/microorganisms7110582] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/15/2019] [Accepted: 11/16/2019] [Indexed: 11/18/2022] Open
Abstract
Shiga toxin (Stx) producing Escherichia coli (STEC) cause the edema disease in pigs by releasing the swine-pathogenic Stx2e subtype as the key virulence factor. Stx2e targets endothelial cells of animal organs including the kidney harboring the Stx receptor glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer, Galα1-4Galβ1-4Glcβ1-1Cer) and globotetraosylceramide (Gb4Cer, GalNAcβ1-3Galα1-4Galβ1-4Glcβ1-1Cer). Since the involvement of renal epithelial cells in the edema disease is unknown, in this study, we analyzed the porcine kidney epithelial cell lines, LLC-PK1 and PK-15, regarding the presence of Stx-binding GSLs, their sensitivity towards Stx2e, and the inhibitory potential of Gb3- and Gb4-neoglycolipids, carrying phosphatidylethanolamine (PE) as the lipid anchor, towards Stx2e. Immunochemical and mass spectrometric analysis revealed various Gb3Cer and Gb4Cer lipoforms as the dominant Stx-binding GSLs in both LLC-PK1 and PK-15 cells. A dihexosylceramide with proposed Galα1-4Gal-sequence (Gal2Cer) was detected in PK-15 cells, whereas LLC-PK1 cells lacked this compound. Both cell lines were susceptible towards Stx2e with LLC-PK1 representing an extremely Stx2e-sensitive cell line. Gb3-PE and Gb4-PE applied as glycovesicles significantly reduced the cytotoxic activity of Stx2e towards LLC-PK1 cells, whereas only Gb4-PE exhibited some protection against Stx2e for PK-15 cells. This is the first report identifying Stx2e receptors of porcine kidney epithelial cells and providing first data on their Stx2e-mediated damage suggesting possible involvement in the edema disease.
Collapse
Affiliation(s)
- Johanna Detzner
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.G.); (G.P.); (N.L.); (A.M.); (H.K.)
| | - Caroline Gloerfeld
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.G.); (G.P.); (N.L.); (A.M.); (H.K.)
| | - Gottfried Pohlentz
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.G.); (G.P.); (N.L.); (A.M.); (H.K.)
| | - Nadine Legros
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.G.); (G.P.); (N.L.); (A.M.); (H.K.)
| | - Hans-Ulrich Humpf
- Institute for Food Chemistry, University of Münster, 48149 Münster, Germany;
| | - Alexander Mellmann
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.G.); (G.P.); (N.L.); (A.M.); (H.K.)
| | - Helge Karch
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.G.); (G.P.); (N.L.); (A.M.); (H.K.)
| | - Johannes Müthing
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.G.); (G.P.); (N.L.); (A.M.); (H.K.)
- Correspondence: ; Tel.: +49-(0)251-8355192
| |
Collapse
|
15
|
Bimodal Response to Shiga Toxin 2 Subtypes Results from Relatively Weak Binding to the Target Cell. Infect Immun 2019; 87:IAI.00428-19. [PMID: 31527121 DOI: 10.1128/iai.00428-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 09/07/2019] [Indexed: 01/15/2023] Open
Abstract
There are two major antigenic forms of Shiga toxin (Stx), Stx1 and Stx2, which bind the same receptor and act on the same target but nonetheless differ in potency. Stx1a is more toxic to cultured cells, but Stx2 subtypes are more potent in animal models. To understand this phenomenon in cultured cells, we used a system that combines flow cytometry with a fluorescent reporter to monitor the Stx-induced inhibition of protein synthesis in single cells. We observed that Vero cells intoxicated with Stx1a behave differently than those intoxicated with Stx2 subtypes: cells challenged with Stx1a exhibited a population-wide loss of protein synthesis, while cells exposed to Stx2a or Stx2c exhibited a dose-dependent bimodal response in which one subpopulation of cells was unaffected (i.e., no loss of protein synthesis). Cells challenged with a hybrid toxin containing the catalytic subunit of Stx1a and the cell-binding subunit of Stx2a also exhibited a bimodal response to intoxication, while cells challenged with a hybrid toxin containing the catalytic subunit of Stx2a and the cell-binding subunit of Stx1a exhibited a population-wide loss of protein synthesis. Other experiments further supported a primary role for the subtype of the B subunit in the outcome of host-Stx interactions. Our collective observations indicate that the bimodal response to Stx2 subtypes is due to relatively weak binding between Stx2 and the host cell that reduces the total functional pool of Stx2 in comparison to that of Stx1a. This explains, in part, the molecular basis for the differential cellular toxicity between Stx1a and Stx2 subtypes.
Collapse
|
16
|
Álvarez RS, Jancic C, Garimano N, Sacerdoti F, Paton AW, Paton JC, Ibarra C, Amaral MM. Crosstalk between Human Microvascular Endothelial Cells and Tubular Epithelial Cells Modulates Pro-Inflammatory Responses Induced by Shiga Toxin Type 2 and Subtilase Cytotoxin. Toxins (Basel) 2019; 11:toxins11110648. [PMID: 31703347 PMCID: PMC6891416 DOI: 10.3390/toxins11110648] [Citation(s) in RCA: 5] [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: 10/11/2019] [Revised: 11/01/2019] [Accepted: 11/05/2019] [Indexed: 01/18/2023] Open
Abstract
Hemolytic uremic syndrome (HUS) is a consequence of Shiga toxin (Stx)-producing Escherichia coli (STEC) infection and is the most frequent cause of acute renal failure (ARF) in children. Subtilase cytotoxin (SubAB) has also been associated with HUS pathogenesis. We previously reported that Stx2 and SubAB cause different effects on co-cultures of human renal microvascular endothelial cells (HGEC) and human proximal tubular epithelial cells (HK-2) relative to HGEC and HK-2 monocultures. In this work we have analyzed the secretion of pro-inflammatory cytokines by co-cultures compared to monocultures exposed or not to Stx2, SubAB, and Stx2+SubAB. Under basal conditions, IL-6, IL-8 and TNF-α secretion was different between monocultures and co-cultures. After toxin treatments, high concentrations of Stx2 and SubAB decreased cytokine secretion by HGEC monocultures, but in contrast, low toxin concentrations increased their release. Toxins did not modulate the cytokine secretion by HK-2 monocultures, but increased their release in the HK-2 co-culture compartment. In addition, HK-2 monocultures were stimulated to release IL-8 after incubation with HGEC conditioned media. Finally, Stx2 and SubAB were detected in HGEC and HK-2 cells from the co-cultures. This work describes, for the first time, the inflammatory responses induced by Stx2 and SubAB, in a crosstalk model of renal endothelial and epithelial cells.
Collapse
Affiliation(s)
- Romina S. Álvarez
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina; (R.S.Á.); (N.G.); (F.S.); (C.I.)
| | - Carolina Jancic
- Laboratorio de Inmunidad Innata, Instituto de Medicina Experimental (IMEX-CONICET), Academia Nacional de Medicina, Buenos Aires 1425, Argentina;
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina
| | - Nicolás Garimano
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina; (R.S.Á.); (N.G.); (F.S.); (C.I.)
| | - Flavia Sacerdoti
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina; (R.S.Á.); (N.G.); (F.S.); (C.I.)
| | - Adrienne W. Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide 5005, Australia; (A.W.P.); (J.C.P.)
| | - James C. Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide 5005, Australia; (A.W.P.); (J.C.P.)
| | - Cristina Ibarra
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina; (R.S.Á.); (N.G.); (F.S.); (C.I.)
| | - María M. Amaral
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina; (R.S.Á.); (N.G.); (F.S.); (C.I.)
- Correspondence:
| |
Collapse
|
17
|
To CZ, Bhunia AK. Three Dimensional Vero Cell-Platform for Rapid and Sensitive Screening of Shiga-Toxin Producing Escherichia coli. Front Microbiol 2019; 10:949. [PMID: 31134009 PMCID: PMC6514307 DOI: 10.3389/fmicb.2019.00949] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 04/15/2019] [Indexed: 01/27/2023] Open
Abstract
Shiga-toxin producing Escherichia coli (STEC) is a serious public health concern. Current Vero cell assay, although sensitive, is lengthy and requires 48-72 h to assess STEC presence in a sample. In this study, we investigated if Vero cells in a three-dimensional (3D) platform would provide improved sensitivity for rapid screening of STEC. Vero cells (epithelial kidney cell line) were grown as a monolayer (2D) or in a collagen-matrix (3D) and exposed to Shiga-toxin (Stx) preparation or STEC cells that were pre-exposed to antibiotics (mitomycin C, ciprofloxacin, or polymyxin B) for toxin induction. Lactate dehydrogenase (LDH) release from Vero cells was used as a biomarker for cytotoxicity. Modified tryptic soy broth (mTSB) as enrichment broth containing mitomycin C (2 μg/ml) or ciprofloxacin (100 ng/ml) significantly induced Stx production, which was further confirmed by the dot-immunoblot assay. The 3D Vero platform detected STEC after 6 h post-infection with cytotoxicity values ranging from 33 to 79%, which is considerably faster than the traditional 2D platform, when tested with STEC. The cytotoxicity for non-Stx producing bacteria, Salmonella, Listeria, Citrobacter, Serratia, and Hafnia was found to be below the cytotoxicity cutoff value of 15%. The detection limit for the 3D Vero cell assay was estimated to be 107 CFU/ml for bacteria and about 32 ng/ml for Stx in 6 h. STEC-inoculated ground beef samples (n = 27) resulted in 38-46% cytotoxicity, and the bacterial isolates (n = 42) from ground beef samples were further confirmed to be stx1 and stx2 positive in a multiplex PCR yielding a very low false-positive result. This 3D cell-based screening assay relies on mammalian cell pathogen interaction that can complement other molecular techniques for the detection of cell-free Stx or STEC cells from food samples for early detection and prevention.
Collapse
Affiliation(s)
- Celina Z. To
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, United States
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, United States
| |
Collapse
|
18
|
Lee MS, Tesh VL. Roles of Shiga Toxins in Immunopathology. Toxins (Basel) 2019; 11:E212. [PMID: 30970547 PMCID: PMC6521259 DOI: 10.3390/toxins11040212] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 04/04/2019] [Accepted: 04/05/2019] [Indexed: 12/20/2022] Open
Abstract
Shigella species and Shiga toxin-producing Escherichia coli (STEC) are agents of bloody diarrhea that may progress to potentially lethal complications such as diarrhea-associated hemolytic uremic syndrome (D+HUS) and neurological disorders. The bacteria share the ability to produce virulence factors called Shiga toxins (Stxs). Research over the past two decades has identified Stxs as multifunctional toxins capable of inducing cell stress responses in addition to their canonical ribotoxic function inhibiting protein synthesis. Notably, Stxs are not only potent inducers of cell death, but also activate innate immune responses that may lead to inflammation, and these effects may increase the severity of organ injury in patients infected with Stx-producing bacteria. In the intestines, kidneys, and central nervous system, excessive or uncontrolled host innate and cellular immune responses triggered by Stxs may result in sensitization of cells to toxin mediated damage, leading to immunopathology and increased morbidity and mortality in animal models (including primates) and human patients. Here, we review studies describing Stx-induced innate immune responses that may be associated with tissue damage, inflammation, and complement activation. We speculate on how these processes may contribute to immunopathological responses to the toxins.
Collapse
Affiliation(s)
- Moo-Seung Lee
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, Korea.
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), 127 Gajeong-ro, Yuseong-gu, Daejeon 34113, Korea.
| | - Vernon L Tesh
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77807, USA.
| |
Collapse
|
19
|
Brigotti M, Orth-Höller D, Carnicelli D, Porcellini E, Galassi E, Tazzari PL, Ricci F, Manoli F, Manet I, Talasz H, Lindner HH, Speth C, Erbeznik T, Fuchs S, Posch W, Chatterjee S, Würzner R. The structure of the Shiga toxin 2a A-subunit dictates the interactions of the toxin with blood components. Cell Microbiol 2019; 21:e13000. [PMID: 30578712 PMCID: PMC6492301 DOI: 10.1111/cmi.13000] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/06/2018] [Accepted: 12/17/2018] [Indexed: 12/29/2022]
Abstract
Hemolytic uremic syndrome (eHUS) is a severe complication of human infections with Shiga toxins (Stxs)-producing Escherichia coli. A key step in the pathogenesis of eHUS is the interaction of Stxs with blood components before the targeting of renal endothelial cells. Here, we show that a single proteolytic cleavage in the Stx2a A-subunit, resulting into two fragments (A1 and A2) linked by a disulfide bridge (cleaved Stx2a), dictates different binding abilities. Uncleaved Stx2a was confirmed to bind to human neutrophils and to trigger leukocyte/platelet aggregate formation, whereas cleaved Stx2a was ineffective. Conversely, binding of complement factor H was confirmed for cleaved Stx2a and not for uncleaved Stx2a. It is worth noting that uncleaved and cleaved Stx2a showed no differences in cytotoxicity for Vero cells or Raji cells, structural conformation, and contaminating endotoxin. These results have been obtained by comparing two Stx2a batches, purified in different laboratories by using different protocols, termed Stx2a(cl; cleaved toxin, Innsbruck) and Stx2a(uncl; uncleaved toxin, Bologna). Stx2a(uncl) behaved as Stx2a(cl) after mild trypsin treatment. In this light, previous controversial results obtained with purified Stx2a has to be critically re-evaluated; furthermore, characterisation of the structure of circulating Stx2a is mandatory to understand eHUS-pathogenesis and to develop therapeutic approaches.
Collapse
Affiliation(s)
- Maurizio Brigotti
- Dipartimento di Medicina Specialistica, Diagnostica e Sperimentale, Sede di Patologia Generale, Università di Bologna, Bologna, Italy
| | - Dorothea Orth-Höller
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Domenica Carnicelli
- Dipartimento di Medicina Specialistica, Diagnostica e Sperimentale, Sede di Patologia Generale, Università di Bologna, Bologna, Italy
| | - Elisa Porcellini
- Dipartimento di Medicina Specialistica, Diagnostica e Sperimentale, Sede di Patologia Generale, Università di Bologna, Bologna, Italy
| | - Elisabetta Galassi
- Dipartimento di Medicina Specialistica, Diagnostica e Sperimentale, Sede di Patologia Generale, Università di Bologna, Bologna, Italy
| | - Pier Luigi Tazzari
- Servizio di Immunoematologia e Trasfusionale, Ospedale S. Orsola-Malpighi, Bologna, Italy
| | - Francesca Ricci
- Servizio di Immunoematologia e Trasfusionale, Ospedale S. Orsola-Malpighi, Bologna, Italy
| | - Francesco Manoli
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, Bologna, Italy
| | - Ilse Manet
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, Bologna, Italy
| | - Heribert Talasz
- Division of Clinical Biochemistry, Biocentre, Medical University of Innsbruck, Innsbruck, Austria
| | - Herbert H Lindner
- Division of Clinical Biochemistry, Biocentre, Medical University of Innsbruck, Innsbruck, Austria
| | - Cornelia Speth
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Thomas Erbeznik
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Stefan Fuchs
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Wilfried Posch
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Sneha Chatterjee
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Reinhard Würzner
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| |
Collapse
|
20
|
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.
Collapse
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.
| |
Collapse
|
21
|
Legros N, Pohlentz G, Steil D, Kouzel IU, Liashkovich I, Mellmann A, Karch H, Müthing J. Membrane assembly of Shiga toxin glycosphingolipid receptors and toxin refractiveness of MDCK II epithelial cells. J Lipid Res 2018; 59:1383-1401. [PMID: 29866658 DOI: 10.1194/jlr.m083048] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 05/22/2018] [Indexed: 12/16/2022] Open
Abstract
Shiga toxins (Stxs) are the major virulence factors of Stx-producing Escherichia coli (STEC), which cause hemorrhagic colitis and severe extraintestinal complications due to injury of renal endothelial cells, resulting in kidney failure. Since kidney epithelial cells are suggested additional targets for Stxs, we analyzed Madin-Darby canine kidney (MDCK) II epithelial cells for presence of Stx-binding glycosphingolipids (GSLs), determined their distribution to detergent-resistant membranes (DRMs), and ascertained the lipid composition of DRM and non-DRM preparations. Globotriaosylceramide and globotetraosylceramide, known as receptors for Stx1a, Stx2a, and Stx2e, and Forssman GSL as a specific receptor for Stx2e, were found to cooccur with SM and cholesterol in DRMs of MDCK II cells, which was shown using TLC overlay assay detection combined with mass spectrometry. The various lipoforms of GSLs were found to mainly harbor ceramide moieties composed of sphingosine (d18:1) and C24:1/C24:0 or C16:0 FA. The cells were highly refractory toward Stx1a, Stx2a, and Stx2e, most likely due to the absence of Stx-binding GSLs in the apical plasma membrane determined by immunofluorescence confocal laser scanning microscopy. The results suggest that the cellular content of Stx receptor GSLs and their biochemical detection in DRM preparations alone are inadequate to predict cellular sensitivity toward Stxs.
Collapse
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
| | - Ivan U Kouzel
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany.,Interdisciplinary Center for Clinical Research, University of Münster, D-48149 Münster, Germany
| | - Ivan Liashkovich
- Institute of Physiology II, University of Münster, D-48149 Münster, Germany
| | - Alexander Mellmann
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany.,Interdisciplinary Center for Clinical Research, University of Münster, D-48149 Münster, Germany
| | - Helge Karch
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany.,Interdisciplinary Center for Clinical Research, University of Münster, D-48149 Münster, Germany
| | - Johannes Müthing
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany .,Interdisciplinary Center for Clinical Research, University of Münster, D-48149 Münster, Germany
| |
Collapse
|
22
|
Park JY, Jeong YJ, Park SK, Yoon SJ, Choi S, Jeong DG, Chung SW, Lee BJ, Kim JH, Tesh VL, Lee MS, Park YJ. Shiga Toxins Induce Apoptosis and ER Stress in Human Retinal Pigment Epithelial Cells. Toxins (Basel) 2017; 9:toxins9100319. [PMID: 29027919 PMCID: PMC5666366 DOI: 10.3390/toxins9100319] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 10/06/2017] [Accepted: 10/06/2017] [Indexed: 01/03/2023] Open
Abstract
Shiga toxins (Stxs) produced by Shiga toxin-producing bacteria Shigella dysenteriae serotype 1 and select serotypes of Escherichia coli are the most potent known virulence factors in the pathogenesis of hemorrhagic colitis progressing to potentially fatal systemic complications such as acute renal failure, blindness and neurological abnormalities. Although numerous studies have defined apoptotic responses to Shiga toxin type 1 (Stx1) or Shiga toxin type 2 (Stx2) in a variety of cell types, the potential significance of Stx-induced apoptosis of photoreceptor and pigmented cells of the eye following intoxication is unknown. We explored the use of immortalized human retinal pigment epithelial (RPE) cells as an in vitro model of Stx-induced retinal damage. To the best of our knowledge, this study is the first report that intoxication of RPE cells with Stxs activates both apoptotic cell death signaling and the endoplasmic reticulum (ER) stress response. Using live-cell imaging analysis, fluorescently labeled Stx1 or Stx2 were internalized and routed to the RPE cell endoplasmic reticulum. RPE cells were significantly sensitive to wild type Stxs by 72 h, while the cells survived challenge with enzymatically deficient mutant toxins (Stx1A− or Stx2A−). Upon exposure to purified Stxs, RPE cells showed activation of a caspase-dependent apoptotic program involving a reduction of mitochondrial transmembrane potential (Δψm), increased activation of ER stress sensors IRE1, PERK and ATF6, and overexpression CHOP and DR5. Finally, we demonstrated that treatment of RPE cells with Stxs resulted in the activation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK), suggesting that the ribotoxic stress response may be triggered. Collectively, these data support the involvement of Stx-induced apoptosis in ocular complications of intoxication. The evaluation of apoptotic responses to Stxs by cells isolated from multiple organs may reveal unique functional patterns of the cytotoxic actions of these toxins in the systemic complications that follow ingestion of toxin-producing bacteria.
Collapse
Affiliation(s)
- Jun-Young Park
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, South Korea.
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), 127 Gajeong-ro, Yuseong-gu, Daejeon 34113, South Korea.
| | - Yu-Jin Jeong
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, South Korea.
- Department of Biochemistry, College of Medicine, Konyang University, 158 Gwanjeo-ro, Daejeon 35365, South Korea.
| | - Sung-Kyun Park
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, South Korea.
| | - Sung-Jin Yoon
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, South Korea.
| | - Song Choi
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, South Korea.
| | - Dae Gwin Jeong
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, South Korea.
| | - Su Wol Chung
- School of Biological Sciences, College of Natural Sciences, University of Ulsan, 93 Daehak-ro, Ulsan 44610, South Korea.
| | - Byung Joo Lee
- Fight Against Angiogenesis-Related Blindness Laboratory, Biomedical Research Institute, Seoul National University Hospital, Seoul 03080, South Korea.
| | - Jeong Hun Kim
- Fight Against Angiogenesis-Related Blindness Laboratory, Biomedical Research Institute, Seoul National University Hospital, Seoul 03080, South Korea.
| | - Vernon L Tesh
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan, TX 77807, USA.
| | - Moo-Seung Lee
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, South Korea.
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), 127 Gajeong-ro, Yuseong-gu, Daejeon 34113, South Korea.
| | - Young-Jun Park
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, South Korea.
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), 127 Gajeong-ro, Yuseong-gu, Daejeon 34113, South Korea.
| |
Collapse
|
23
|
Hall G, Kurosawa S, Stearns-Kurosawa DJ. Shiga Toxin Therapeutics: Beyond Neutralization. Toxins (Basel) 2017; 9:toxins9090291. [PMID: 28925976 PMCID: PMC5618224 DOI: 10.3390/toxins9090291] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 09/15/2017] [Accepted: 09/15/2017] [Indexed: 01/04/2023] Open
Abstract
Ribotoxic Shiga toxins are the primary cause of hemolytic uremic syndrome (HUS) in patients infected with Shiga toxin-producing enterohemorrhagic Escherichia coli (STEC), a pathogen class responsible for epidemic outbreaks of gastrointestinal disease around the globe. HUS is a leading cause of pediatric renal failure in otherwise healthy children, resulting in a mortality rate of 10% and a chronic morbidity rate near 25%. There are currently no available therapeutics to prevent or treat HUS in STEC patients despite decades of work elucidating the mechanisms of Shiga toxicity in sensitive cells. The preclinical development of toxin-targeted HUS therapies has been hindered by the sporadic, geographically dispersed nature of STEC outbreaks with HUS cases and the limited financial incentive for the commercial development of therapies for an acute disease with an inconsistent patient population. The following review considers potential therapeutic targeting of the downstream cellular impacts of Shiga toxicity, which include the unfolded protein response (UPR) and the ribotoxic stress response (RSR). Outcomes of the UPR and RSR are relevant to other diseases with large global incidence and prevalence rates, thus reducing barriers to the development of commercial drugs that could improve STEC and HUS patient outcomes.
Collapse
Affiliation(s)
- Gregory Hall
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Shinichiro Kurosawa
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Deborah J Stearns-Kurosawa
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA.
| |
Collapse
|
24
|
Márquez LB, Araoz A, Repetto HA, Ibarra FR, Silberstein C. Effects of shiga toxin 2 on cellular regeneration mechanisms in primary and three-dimensional cultures of human renal tubular epithelial cells. Microb Pathog 2016; 99:87-94. [PMID: 27521227 DOI: 10.1016/j.micpath.2016.08.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 08/05/2016] [Accepted: 08/08/2016] [Indexed: 01/02/2023]
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) causes post-diarrheal Hemolytic Uremic Syndrome (HUS), which is one of the most common causes of acute renal failure in children in Argentine. The aim of the present work was to study the effects of Shiga toxin type 2 (Stx2) on regenerative mechanisms of primary cultures of human cortical renal tubular epithelial cells (HRTEC) and three-dimensional (3D) cultures of HRTEC. Primary cultures of HRTEC were able to develop tubular structures when grown in matrigel, which showed epithelial cells surrounding a central lumen resembling the original renal tubules. Exposure to Stx2 inhibited tubulogenesis in 3D-HRTEC cultures. Moreover, a significant increase in apoptosis, and decrease in cell proliferation was observed in tubular structures of 3D-HRTEC exposed to Stx2. A significant reduction in cell migration and vimentin expression levels was observed in HRTEC primary cultures exposed to Stx2, demonstrating that the holotoxin affected HRTEC dedifferentiation. Furthermore, a decreased number of cells expressing CD133 progenitor marker was found in HRTEC cultures treated with Stx2. The CD133 positive cells also expressed the Stx receptor globotriaosylceramide, which may explain their sensitivity to Stx2. In conclusion, Stx2 affects the regenerative processes of human renal tubular epithelial cells in vitro, by inhibiting cell dedifferentiation mechanisms, as well as tubules restoration. The development of 3D-HRTEC cultures that resemble original human renal proximal tubules is a novel in vitro model to study renal epithelial repair mechanisms after injury.
Collapse
Affiliation(s)
- Laura B Márquez
- Departamento de Ciencias Fisiológicas, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 4, Buenos Aires, 1121, Argentina
| | - Alicia Araoz
- Departamento de Ciencias Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, 1121, Argentina
| | - Horacio A Repetto
- Departamento de Pediatría, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, 1121, Argentina
| | - Fernando R Ibarra
- Departamento de Ciencias Fisiológicas, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 4, Buenos Aires, 1121, Argentina; Laboratorio de Riñón Experimental, Instituto de Investigaciones Médicas A. Lanari, Universidad de Buenos Aires, Buenos Aires, 1427, Argentina
| | - Claudia Silberstein
- Departamento de Ciencias Fisiológicas, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 4, Buenos Aires, 1121, Argentina.
| |
Collapse
|
25
|
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.
Collapse
|
26
|
Tang B, Li Q, Zhao XH, Wang HG, Li N, Fang Y, Wang K, Jia YP, Zhu P, Gu J, Li JX, Jiao YJ, Tong WD, Wang M, Zou QM, Zhu FC, Mao XH. Shiga toxins induce autophagic cell death in intestinal epithelial cells via the endoplasmic reticulum stress pathway. Autophagy 2016; 11:344-54. [PMID: 25831014 DOI: 10.1080/15548627.2015.1023682] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Shiga toxins (Stxs) are a family of cytotoxic proteins that lead to the development of bloody diarrhea, hemolytic-uremic syndrome, and central nervous system complications caused by bacteria such as S. dysenteriae, E. coli O157:H7 and E. coli O104:H4. Increasing evidence indicates that macroautophagy (autophagy) is a key factor in the cell death induced by Stxs. However, the associated mechanisms are not yet clear. This study showed that Stx2 induces autophagic cell death in Caco-2 cells, a cultured line model of human enterocytes. Inhibition of autophagy using pharmacological inhibitors, such as 3-methyladenine and bafilomycin A1, or silencing of the autophagy genes ATG12 or BECN1 decreased the Stx2-induced death in Caco-2 cells. Furthermore, there were numerous instances of dilated endoplasmic reticulum (ER) in the Stx2-treated Caco-2 cells, and repression of ER stress due to the depletion of viable candidates of DDIT3 and NUPR1. These processes led to Stx2-induced autophagy and cell death. Finally, the data showed that the pseudokinase TRIB3-mediated DDIT3 expression and AKT1 dephosphorylation upon ER stress were triggered by Stx2. Thus, the data indicate that Stx2 causes autophagic cell death via the ER stress pathway in intestinal epithelial cells.
Collapse
Key Words
- 3-MA, 3-methyladenine
- AO, acridine orange
- ATF4, activating transcription factor 4
- ATG, autophagy-related
- BECN1, Beclin 1, autophagy-related
- Baf A1, bafilomycin A1
- CASP3, caspase 3, apoptosis-related cysteine peptidase
- DDIT3, DNA-damage-inducible transcript 3
- E. coli O157:H7
- EHEC O157, Escherichia coli O157:H7
- ER stress
- FACS, fluorescence activated cell sorting
- MAP1LC3B, microtubule-associated protein 1 light chain 3 beta
- MAPK, mitogen-activated protein kinase
- MDC, monodansylcadaverine
- NUPR1, nuclear protein, transcriptional regulator, 1
- PARP1, poly (ADP-ribose) polymerase 1
- PBS, phosphate-buffered saline
- PI, propidium iodide
- Shiga toxins
- Stxs, Shiga toxins
- TEM, transmission electron microscopy
- TRIB3, tribbles pseudokinase 3
- Thap, thapsigargin
- WT, wild type
- Z-VAD, Z-VAD-FMK
- autophagic cell death
- autophagy
- Δ, knockout
Collapse
Affiliation(s)
- Bin Tang
- a National Engineering Research Center for Immunobiological Products; Department of Microbiology and Biochemical Pharmacy; College of Pharmacy; Third Military Medical University ; Chongqing , China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Shiga Toxins Activate the NLRP3 Inflammasome Pathway To Promote Both Production of the Proinflammatory Cytokine Interleukin-1β and Apoptotic Cell Death. Infect Immun 2015; 84:172-86. [PMID: 26502906 DOI: 10.1128/iai.01095-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 10/16/2015] [Indexed: 02/06/2023] Open
Abstract
Shiga toxin (Stx)-mediated immune responses, including the production of the proinflammatory cytokines tumor necrosis-α (TNF-α) and interleukin-1β (IL-1β), may exacerbate vascular damage and accelerate lethality. However, the immune signaling pathway activated in response to Stx is not well understood. Here, we demonstrate that enzymatically active Stx, which leads to ribotoxic stress, triggers NLRP3 inflammasome-dependent caspase-1 activation and IL-1β secretion in differentiated macrophage-like THP-1 (D-THP-1) cells. The treatment of cells with a chemical inhibitor of glycosphingolipid biosynthesis, which suppresses the expression of the Stx receptor globotriaosylceramide and subsequent endocytosis of the toxin, substantially blocked activation of the NLRP3 inflammasome and processing of caspase-1 and IL-1β. Processing and release of both caspase-1 and IL-1β were significantly reduced or abolished in Stx-intoxicated D-THP-1 cells in which the expression of NLRP3 or ASC was stably knocked down. Furthermore, Stx mediated the activation of caspases involved in apoptosis in an NLRP3- or ASC-dependent manner. In Stx-intoxicated cells, the NLRP3 inflammasome triggered the activation of caspase-8/3, leading to the initiation of apoptosis, in addition to caspase-1-dependent pyroptotic cell death. Taken together, these results suggest that Stxs trigger the NLRP3 inflammasome pathway to release proinflammatory IL-1β as well as to promote apoptotic cell death.
Collapse
|
28
|
Effects of Shiga toxin type 2 on a bioengineered three-dimensional model of human renal tissue. Infect Immun 2014; 83:28-38. [PMID: 25312954 DOI: 10.1128/iai.02143-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shiga toxins (Stx) are a family of cytotoxic proteins that can cause hemolytic-uremic syndrome (HUS), a thrombotic microangiopathy, following infections by Shiga toxin-producing Escherichia coli (STEC). Renal failure is a key feature of HUS and a major cause of childhood renal failure worldwide. There are currently no specific therapies for STEC-associated HUS, and the mechanism of Stx-induced renal injury is not well understood primarily due to a lack of fully representative animal models and an inability to monitor disease progression on a molecular or cellular level in humans at early stages. Three-dimensional (3D) tissue models have been shown to be more in vivo-like in their phenotype and physiology than 2D cultures for numerous disease models, including cancer and polycystic kidney disease. It is unknown whether exposure of a 3D renal tissue model to Stx will yield a more in vivo-like response than 2D cell culture. In this study, we characterized Stx2-mediated cytotoxicity in a bioengineered 3D human renal tissue model previously shown to be a predictor of drug-induced nephrotoxicity and compared its response to Stx2 exposure in 2D cell culture. Our results demonstrate that although many mechanistic aspects of cytotoxicity were similar between 3D and 2D, treatment of the 3D tissues with Stx resulted in an elevated secretion of the kidney injury marker 1 (Kim-1) and the cytokine interleukin-8 compared to the 2D cell cultures. This study represents the first application of 3D tissues for the study of Stx-mediated kidney injury.
Collapse
|
29
|
Abstract
Shiga toxin (Stx) is one of the most potent bacterial toxins known. Stx is found in Shigella dysenteriae 1 and in some serogroups of Escherichia coli (called Stx1 in E. coli). In addition to or instead of Stx1, some E. coli strains produce a second type of Stx, Stx2, that has the same mode of action as Stx/Stx1 but is antigenically distinct. Because subtypes of each toxin have been identified, the prototype toxin for each group is now designated Stx1a or Stx2a. The Stxs consist of two major subunits, an A subunit that joins noncovalently to a pentamer of five identical B subunits. The A subunit of the toxin injures the eukaryotic ribosome and halts protein synthesis in target cells. The function of the B pentamer is to bind to the cellular receptor, globotriaosylceramide, Gb3, found primarily on endothelial cells. The Stxs traffic in a retrograde manner within the cell, such that the A subunit of the toxin reaches the cytosol only after the toxin moves from the endosome to the Golgi and then to the endoplasmic reticulum. In humans infected with Stx-producing E. coli, the most serious manifestation of the disease, hemolytic-uremic syndrome, is more often associated with strains that produce Stx2a rather than Stx1a, and that relative toxicity is replicated in mice and baboons. Stx1a and Stx2a also exhibit differences in cytotoxicity to various cell types, bind dissimilarly to receptor analogs or mimics, induce differential chemokine responses, and have several distinctive structural characteristics.
Collapse
Affiliation(s)
- Angela R. Melton-Celsa
- Department of Microbiology & Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814,
| |
Collapse
|
30
|
Porubsky S, Federico G, Müthing J, Jennemann R, Gretz N, Büttner S, Obermüller N, Jung O, Hauser IA, Gröne E, Geiger H, Gröne HJ, Betz C. Direct acute tubular damage contributes to Shigatoxin-mediated kidney failure. J Pathol 2014; 234:120-33. [PMID: 24909663 PMCID: PMC4282478 DOI: 10.1002/path.4388] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 05/29/2014] [Accepted: 06/04/2014] [Indexed: 01/11/2023]
Abstract
The pathogenesis and therapy of Shigatoxin 2 (Stx2)-mediated kidney failure remain controversial. Our aim was to test whether, during an infection with Stx2-producing E. coli (STEC), Stx2 exerts direct effects on renal tubular epithelium and thereby possibly contributes to acute renal failure. Mice represent a suitable model because they, like humans, express the Stx2-receptor Gb3 in the tubular epithelium but, in contrast to humans, not in glomerular endothelia, and are thus free of glomerular thrombotic microangiopathy (TMA). In wild-type mice, Stx2 caused acute tubular dysfunction with consequent electrolyte disturbance, which was most likely the cause of death. Tubule-specific depletion of Gb3 protected the mice from acute renal failure. In vitro, Stx2 induced secretion of proinflammatory cytokines and apoptosis in human tubular epithelial cells, thus implicating a direct effect of Stx2 on the tubular epithelium. To correlate these results to human disease, kidney biopsies and outcome were analysed in patients with Stx2-associated kidney failure (n = 11, aged 22–44 years). The majority of kidney biopsies showed different stages of an ongoing TMA; however, no glomerular complement activation could be demonstrated. All biopsies, including those without TMA, showed severe acute tubular damage. Due to these findings, patients were treated with supportive therapy without complement-inhibiting antibodies (eculizumab) or immunoadsorption. Despite the severity of the initial disease [creatinine 6.34 (1.31–17.60) mg/dl, lactate dehydrogenase 1944 (753–2792) U/l, platelets 33 (19–124)/nl and haemoglobin 6.2 (5.2–7.8) g/dl; median (range)], all patients were discharged after 33 (range 19–43) days with no neurological symptoms and no dialysis requirement [creatinine 1.39 (range 0.84–2.86) mg/dl]. The creatinine decreased further to 0.90 (range 0.66–1.27) mg/dl after 24 months. Based on these data, one may surmise that acute tubular damage represents a separate pathophysiological mechanism, importantly contributing to Stx2-mediated acute kidney failure. Specifically in young adults, an excellent outcome can be achieved by supportive therapy only. © 2014 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Collapse
Affiliation(s)
- Stefan Porubsky
- Department of Cellular and Molecular Pathology, German Cancer Research Centre, Heidelberg, Germany; Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Márquez LB, Velázquez N, Repetto HA, Paton AW, Paton JC, Ibarra C, Silberstein C. Effects of Escherichia coli subtilase cytotoxin and Shiga toxin 2 on primary cultures of human renal tubular epithelial cells. PLoS One 2014; 9:e87022. [PMID: 24466317 PMCID: PMC3897771 DOI: 10.1371/journal.pone.0087022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 12/17/2013] [Indexed: 12/21/2022] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) cause post-diarrhea Hemolytic Uremic Syndrome (HUS), which is the most common cause of acute renal failure in children in many parts of the world. Several non-O157 STEC strains also produce Subtilase cytotoxin (SubAB) that may contribute to HUS pathogenesis. The aim of the present work was to examine the cytotoxic effects of SubAB on primary cultures of human cortical renal tubular epithelial cells (HRTEC) and compare its effects with those produced by Shiga toxin type 2 (Stx2), in order to evaluate their contribution to renal injury in HUS. For this purpose, cell viability, proliferation rate, and apoptosis were assayed on HRTEC incubated with SubAB and/or Stx2 toxins. SubAB significantly reduced cell viability and cell proliferation rate, as well as stimulating cell apoptosis in HRTEC cultures in a time dependent manner. However, HRTEC cultures were significantly more sensitive to the cytotoxic effects of Stx2 than those produced by SubAB. No synergism was observed when HRTEC were co-incubated with both SubAB and Stx2. When HRTEC were incubated with the inactive SubAA272B toxin, results were similar to those in untreated control cells. Similar stimulation of apoptosis was observed in Vero cells incubated with SubAB or/and Stx2, compared to HRTEC. In conclusion, primary cultures of HRTEC are significantly sensitive to the cytotoxic effects of SubAB, although, in a lesser extent compared to Stx2.
Collapse
Affiliation(s)
- Laura B. Márquez
- Laboratorio de Investigaciones Biomédicas, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay, Buenos Aires, Argentina
| | - Natalia Velázquez
- Laboratorio de Investigaciones Biomédicas, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay, Buenos Aires, Argentina
| | - Horacio A. Repetto
- Departamento de Pediatría, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Adrienne W. Paton
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, S.A., Australia
| | - James C. Paton
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, S.A., Australia
| | - Cristina Ibarra
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Claudia Silberstein
- Laboratorio de Investigaciones Biomédicas, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay, Buenos Aires, Argentina
- * E-mail:
| |
Collapse
|
32
|
|
33
|
Lee MS, Kim MH, Tesh VL. Shiga toxins expressed by human pathogenic bacteria induce immune responses in host cells. J Microbiol 2013; 51:724-30. [PMID: 24385347 DOI: 10.1007/s12275-013-3429-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/22/2013] [Indexed: 12/22/2022]
Abstract
Shiga toxins are a family of genetically and structurally related toxins that are the primary virulence factors produced by the bacterial pathogens Shigella dysenteriae serotype 1 and certain Escherichia coli strains. The toxins are multifunctional proteins inducing protein biosynthesis inhibition, ribotoxic and ER stress responses, apoptosis, autophagy, and inflammatory cytokine and chemokine production. The regulated induction of inflammatory responses is key to minimizing damage upon injury or pathogen-mediated infections, requiring the concerted activation of multiple signaling pathways to control cytokine/chemokine expression. Activation of host cell signaling cascades is essential for Shiga toxin-mediated proinflammatory responses and the contribution of the toxins to virulence. Many studies have been reported defining the inflammatory response to Shiga toxins in vivo and in vitro, including production and secretion of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), macrophage inflammatory protein-1α/β (MIP-1α/β), macrophage chemoattractant monocyte chemoattractant protein 1 (MCP-1), interleukin 8 (IL-8), interleukin 6 (IL-6), and Groβ. These cytokines and chemokines may contribute to damage in the colon and development of life threatening conditions such as acute renal failure (hemolytic uremic syndrome) and neurological abnormalities. In this review, we summarize recent findings in Shiga toxin-mediated inflammatory responses by different types of cells in vitro and in animal models. Signaling pathways involved in the inflammatory responses are briefly reviewed.
Collapse
Affiliation(s)
- Moo-Seung Lee
- Infection and Immunity Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 305-806, Republic of Korea,
| | | | | |
Collapse
|
34
|
Shiga toxin type 2dact displays increased binding to globotriaosylceramide in vitro and increased lethality in mice after activation by elastase. Toxins (Basel) 2013; 5:2074-92. [PMID: 24217397 PMCID: PMC3847715 DOI: 10.3390/toxins5112074] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/31/2013] [Accepted: 11/04/2013] [Indexed: 01/24/2023] Open
Abstract
Shiga toxin type 2dact (Stx2dact), an Stx2 variant originally identified from Escherichia coli O91:H21 strain B2F1, displays increased cytotoxicity after activation by elastase present in intestinal mucus. Activation is a result of cleavage of two amino acids from the C-terminal tail of the A2 subunit. In this study, we hypothesized that activation leads to increased binding of toxin to its receptor on host cells both in vitro and in vivo. To test this theory, Stx2dact was treated with elastase or buffer alone and then each toxin was assessed for binding to purified globotriaosylceramide (Gb3) in an enzyme-linked immunosorbent assay, or cells in culture by immunofluorescence, or flow cytometry. Elastase- and buffer-treated Stx2dact were also evaluated for binding to mouse kidney tissue and for relative lethality in mice. We found that activated Stx2dact had a greater capacity to bind purified Gb3, cells in culture, and mouse kidney tissue and was more toxic for mice than was non-activated Stx2dact. Thus, one possible mechanism for the augmented cytotoxicity of Stx2dact after activation is its increased capacity to bind target cells, which, in turn, may cause greater lethality of elastase-treated toxin for mice and enhanced virulence for humans of E. coli strains that express Stx2dact.
Collapse
|
35
|
Purification and characterization of Shiga toxin 2f, an immunologically unrelated subtype of Shiga toxin 2. PLoS One 2013; 8:e59760. [PMID: 23555772 PMCID: PMC3608586 DOI: 10.1371/journal.pone.0059760] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 02/17/2013] [Indexed: 01/01/2023] Open
Abstract
Background Shiga-like toxin 2 (Stx2) is one of the most important virulence factors in enterohaemorrhagic Escherichia coli (E. coli) strains such as O157H7. Subtypes of Stx2 are diverse with respect to their sequence, toxicity, and distribution. The most diverse Stx2 subtype, Stx2f, is difficult to detect immunologically, but is becoming more frequently associated with human illness. Methods and Findings A purification regimen was developed for the purification of Stx2f involving cation exchange, hydrophobic interaction, anion exchange, and gel filtration. The molecular weight of Stx2f B-subunit was approximately 5 kDa, which appeared significantly smaller than that of Stx2a (6 kDa) on a SDS-PAGE gel, although the size of the A subunit was similar to Stx2a (30 kDa). Stx2f was shown to be active in both cell-free and cell-based assays. The 50% cytotoxic dose in Vero cells was 3.4 or 1.7 pg (depending on the assay conditions), about 3–5 times higher than the archetypical Stx2a, while the activity of Stx2f and Stx2a in a cell-free rabbit reticulocyte system was similar. Stx2f bound to both globotriose-lipopolysaccharide (Gb3-LPS) and globotetraose-LPS (Gb4-LPS, mimics for globotriaosylceramide and globotetraosylceramide, respectively), but its ability to bind Gb4-LPS was much stronger than Stx2a. Stx2f was also much more stable at low pH and high temperature compared to Stx2a, suggesting the toxin itself may survive harsher food preparation practices. Conclusions Here, we detail the purification, biochemical properties, and toxicity of Stx2f, from an E. coli strain isolated from a feral pigeon. Information obtained in this study will be valuable for characterizing Stx2f and explaining the differences of Stx2a and Stx2f in host specificity and cytotoxicity.
Collapse
|
36
|
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
|
37
|
Trachtman H, Austin C, Lewinski M, Stahl RAK. Renal and neurological involvement in typical Shiga toxin-associated HUS. Nat Rev Nephrol 2012; 8:658-69. [PMID: 22986362 DOI: 10.1038/nrneph.2012.196] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Shiga toxin-producing Escherichia coli-associated haemolytic uraemic syndrome (STEC-HUS) is one of the most important causes of acute kidney injury in patients of all ages, especially in children. It can occur sporadically or in outbreaks. STEC-HUS is a systemic illness caused by toxin-mediated injury to the vascular endothelium and a generalized inflammatory response. The kidney and the brain are the two primary target organs. Nearly 40% of patients with STEC-HUS require at least temporary renal replacement therapy and up to 20% will have permanent residual kidney dysfunction. Neurological injury can be sudden and severe and is the most frequent cause of acute mortality in patients with STEC-HUS. Over the past 30 years, a wide range of inflammatory mediators have been linked to the pathogenesis of STEC-HUS and associated renal and neurological complications. Recently, evidence has accumulated that abnormal activation of the alternative pathway of complement occurs in patients with STEC-HUS. In the large outbreak of STEC-HUS caused by E. coli O104:H4 that occurred in Germany in May 2011, a large number of patients received eculizumab, a monoclonal antibody directed against C5, in an open-label manner. We describe the experience with eculizumab under these emergent circumstances at one large centre.
Collapse
Affiliation(s)
- Howard Trachtman
- Department of Pediatrics, Division of Nephrology, NYU Langone Medical Center, Clinical Translational Science Institute, Room 712, 227 East 30th Street, New York, NY 10016-9196, USA.
| | | | | | | |
Collapse
|
38
|
Bergan J, Dyve Lingelem AB, Simm R, Skotland T, Sandvig K. Shiga toxins. Toxicon 2012; 60:1085-107. [PMID: 22960449 DOI: 10.1016/j.toxicon.2012.07.016] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 06/19/2012] [Accepted: 07/25/2012] [Indexed: 02/03/2023]
Abstract
Shiga toxins are virulence factors produced by the bacteria Shigella dysenteriae and certain strains of Escherichia coli. There is currently no available treatment for disease caused by these toxin-producing bacteria, and understanding the biology of the Shiga toxins might be instrumental in addressing this issue. In target cells, the toxins efficiently inhibit protein synthesis by inactivating ribosomes, and they may induce signaling leading to apoptosis. To reach their cytoplasmic target, Shiga toxins are endocytosed and transported by a retrograde pathway to the endoplasmic reticulum, before the enzymatically active moiety is translocated to the cytosol. The toxins thereby serve as powerful tools to investigate mechanisms of intracellular transport. Although Shiga toxins are a serious threat to human health, the toxins may be exploited for medical purposes such as cancer therapy or imaging.
Collapse
Affiliation(s)
- Jonas Bergan
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Norway
| | | | | | | | | |
Collapse
|
39
|
Abstract
Shiga toxin-producing bacteria cause widespread outbreaks of bloody diarrhoea that may progress to life-threatening systemic complications. Shiga toxins (Stxs), the main virulence factors expressed by the pathogens, are ribosome-inactivating proteins which inhibit protein synthesis by removing an adenine residue from 28S rRNA. Recently, Stxs were shown to activate multiple stress-associated signalling pathways in mammalian cells. The ribotoxic stress response is activated following the depurination reaction localized to the α-sarcin/ricin loop of eukaryotic ribosomes. The unfolded protein response (UPR) may be initiated by toxin unfolding within the endoplasmic reticulum, and maintained by production of truncated, misfolded proteins following intoxication. Activation of the ribotoxic stress response leads to signalling through MAPK cascades, which appears to be critical for activation of innate immunity and regulation of apoptosis. Precise mechanisms linking ribosomal damage with MAPK activation require clarification but may involve recognition of ribosomal conformational changes and binding of protein kinases to ribosomes, which activate MAP3Ks and MAP2Ks. Stxs appear capable of activating all ER membrane localized UPR sensors. Prolonged signalling through the UPR induces apoptosis in some cell types. The characterization of stress responses activated by Stxs may identify targets for the development of interventional therapies to block cell damage and disease progression.
Collapse
Affiliation(s)
- Vernon L Tesh
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M Health Science Center, Bryan, TX 77807, USA.
| |
Collapse
|