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Paparella A, Cahill SM, Aboulache BL, Schramm VL. Clostridioides difficile TcdB Toxin Glucosylates Rho GTPase by an S Ni Mechanism and Ion Pair Transition State. ACS Chem Biol 2022; 17:2507-2518. [PMID: 36038138 PMCID: PMC9486934 DOI: 10.1021/acschembio.2c00408] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Toxins TcdA and TcdB from Clostridioides difficile glucosylate human colon Rho GTPases. TcdA and TcdB glucosylation of RhoGTPases results in cytoskeletal changes, causing cell rounding and loss of intestinal integrity. Clostridial toxins TcdA and TcdB are proposed to catalyze glucosylation of Rho GTPases with retention of stereochemistry from UDP-glucose. We used kinetic isotope effects to analyze the mechanisms and transition-state structures of the glucohydrolase and glucosyltransferase activities of TcdB. TcdB catalyzes Rho GTPase glucosylation with retention of stereochemistry, while hydrolysis of UDP-glucose by TcdB causes inversion of stereochemistry. Kinetic analysis revealed TcdB glucosylation via the formation of a ternary complex with no intermediate, supporting an SNi mechanism with nucleophilic attack and leaving group departure occurring on the same face of the glucose ring. Kinetic isotope effects combined with quantum mechanical calculations revealed that the transition states of both glucohydrolase and glucosyltransferase activities of TcdB are highly dissociative. Specifically, the TcdB glucosyltransferase reaction proceeds via an SNi mechanism with the formation of a distinct oxocarbenium phosphate ion pair transition state where the glycosidic bond to the UDP leaving group breaks prior to attack of the threonine nucleophile from Rho GTPase.
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Petersen L, Stroh S, Schöttelndreier D, Grassl GA, Rottner K, Brakebusch C, Fahrer J, Genth H. The Essential Role of Rac1 Glucosylation in Clostridioides difficile Toxin B-Induced Arrest of G1-S Transition. Front Microbiol 2022; 13:846215. [PMID: 35321078 PMCID: PMC8937036 DOI: 10.3389/fmicb.2022.846215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 02/14/2022] [Indexed: 12/18/2022] Open
Abstract
Clostridioides difficile infection (CDI) in humans causes pseudomembranous colitis (PMC), which is a severe pathology characterized by a loss of epithelial barrier function and massive colonic inflammation. PMC has been attributed to the action of two large protein toxins, Toxin A (TcdA) and Toxin B (TcdB). TcdA and TcdB mono-O-glucosylate and thereby inactivate a broad spectrum of Rho GTPases and (in the case of TcdA) also some Ras GTPases. Rho/Ras GTPases promote G1-S transition through the activation of components of the ERK, AKT, and WNT signaling pathways. With regard to CDI pathology, TcdB is regarded of being capable of inhibiting colonic stem cell proliferation and colonic regeneration, which is likely causative for PMC. In particular, it is still unclear, the glucosylation of which substrate Rho-GTPase is critical for TcdB-induced arrest of G1-S transition. Exploiting SV40-immortalized mouse embryonic fibroblasts (MEFs) with deleted Rho subtype GTPases, evidence is provided that Rac1 (not Cdc42) positively regulates Cyclin D1, an essential factor of G1-S transition. TcdB-catalyzed Rac1 glucosylation results in Cyclin D1 suppression and arrested G1-S transition in MEFs and in human colonic epithelial cells (HCEC), Remarkably, Rac1−/− MEFs are insensitive to TcdB-induced arrest of G1-S transition, suggesting that TcdB arrests G1-S transition in a Rac1 glucosylation-dependent manner. Human intestinal organoids (HIOs) specifically expressed Cyclin D1 (neither Cyclin D2 nor Cyclin D3), which expression was suppressed upon TcdB treatment. In sum, Cyclin D1 expression in colonic cells seems to be regulated by Rho GTPases (most likely Rac1) and in turn seems to be susceptible to TcdB-induced suppression. With regard to PMC, toxin-catalyzed Rac1 glucosylation and subsequent G1-S arrest of colonic stem cells seems to be causative for decreased repair capacity of the colonic epithelium and delayed epithelial renewal.
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Affiliation(s)
- Lara Petersen
- Institute for Toxicology, Hannover Medical School, Hannover, Germany
| | - Svenja Stroh
- Department of Toxicology, University Medical Center Mainz, Mainz, Germany
| | | | - Guntram A. Grassl
- Institute of Medical Microbiology and Hospital Epidemiology and DZIF partner site Hannover, Hannover Medical School, Hannover, Germany
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
- Department of Cell Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Cord Brakebusch
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Jörg Fahrer
- Department of Toxicology, University Medical Center Mainz, Mainz, Germany
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Harald Genth
- Institute for Toxicology, Hannover Medical School, Hannover, Germany
- *Correspondence: Harald Genth,
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Aminzadeh A, Tiwari MK, Mamah Mustapha SS, Navarrete SJ, Henriksen AB, Møller IM, Krogfelt KA, Bjerrum MJ, Jørgensen R. Detoxification of toxin A and toxin B by copper ion-catalyzed oxidation in production of a toxoid-based vaccine against Clostridioides difficile. Free Radic Biol Med 2020; 160:433-446. [PMID: 32860983 DOI: 10.1016/j.freeradbiomed.2020.08.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 02/04/2023]
Abstract
Clostridioides difficile infections (CDI) has emerged worldwide as a serious antimicrobial-resistant healthcare-associated disease resulting in diarrhea and pseudomembranous colitis. The two cytotoxic proteins, toxin A (TcdA) and toxin B (TcdB) are the major virulence factor responsible for the disease symptoms. We examined time-dependent oxidative detoxification of TcdA and TcdB using different molar ratios of protein:Cu2+:H2O2. The metal-catalyzed oxidation (MCO) reaction in molar ratios of 1:60:1000 for protein:Cu2+:H2O2 at pH 4.5 resulted in a significant 6 log10 fold reduction in cytotoxicity after 120-min incubation at 37 °C. Circular dichroism revealed that MCO-detoxified TcdA and TcdB had secondary and tertiary structural folds similar to the native proteins. The conservation of immunogenic epitopes of both proteins was tested using monoclonal antibodies in an ELISA, comparing our MCO-detoxification approach to a conventional formaldehyde-detoxification method. The oxidative detoxification of TcdA and TcdB led to an average 2-fold reduction in antibody binding relative to native proteins, whereas formaldehyde cross-linking resulted in 3-fold and 5-fold reductions, respectively. Finally, we show that mice immunized with a vaccine consisting of MCO-detoxified TcdA and TcdB were fully protected against disease symptoms and death following a C. difficile infection and elicited substantial serum IgG responses against both TcdA and TcdB. The results of this study present copper ion-catalyzed oxidative detoxification of toxic proteins as a method highly suitable for the rapid production of safe, immunogenic and irreversible toxoid antigens for future vaccine development and may have the potential for replacing cross-linking reagents like formaldehyde.
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Affiliation(s)
- Aria Aminzadeh
- Statens Serum Institut, Department of Bacteria, Parasites and Fungi, Copenhagen, Denmark; University of Copenhagen, Department of Chemistry, Copenhagen, Denmark
| | | | | | | | | | - Ian Max Møller
- Department of Molecular Biology and Genetics, Aarhus University, Forsøgsvej 1, DK, 4200, Slagelse, Denmark
| | | | | | - René Jørgensen
- Statens Serum Institut, Department of Bacteria, Parasites and Fungi, Copenhagen, Denmark.
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Ost GS, Wirth C, Bogdanović X, Kao WC, Schorch B, Aktories PJK, Papatheodorou P, Schwan C, Schlosser A, Jank T, Hunte C, Aktories K. Inverse control of Rab proteins by Yersinia ADP-ribosyltransferase and glycosyltransferase related to clostridial glucosylating toxins. SCIENCE ADVANCES 2020; 6:eaaz2094. [PMID: 32195351 PMCID: PMC7065874 DOI: 10.1126/sciadv.aaz2094] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/17/2019] [Indexed: 05/20/2023]
Abstract
We identified a glucosyltransferase (YGT) and an ADP-ribosyltransferase (YART) in Yersinia mollaretii, highly related to glucosylating toxins from Clostridium difficile, the cause of antibiotics-associated enterocolitis. Both Yersinia toxins consist of an amino-terminal enzyme domain, an autoprotease domain activated by inositol hexakisphosphate, and a carboxyl-terminal translocation domain. YGT N-acetylglucosaminylates Rab5 and Rab31 at Thr52 and Thr36, respectively, thereby inactivating the Rab proteins. YART ADP-ribosylates Rab5 and Rab31 at Gln79 and Gln64, respectively. This activates Rab proteins by inhibiting GTP hydrolysis. We determined the crystal structure of the glycosyltransferase domain of YGT (YGTG) in the presence and absence of UDP at 1.9- and 3.4-Å resolution, respectively. Thereby, we identified a previously unknown potassium ion-binding site, which explains potassium ion-dependent enhanced glycosyltransferase activity in clostridial and related toxins. Our findings exhibit a novel type of inverse regulation of Rab proteins by toxins and provide new insights into the structure-function relationship of glycosyltransferase toxins.
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Affiliation(s)
- G. Stefan Ost
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
- Institut für Biologie, Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Christophe Wirth
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Xenia Bogdanović
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Wei-Chun Kao
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Björn Schorch
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Philipp J. K. Aktories
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Panagiotis Papatheodorou
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Carsten Schwan
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Andreas Schlosser
- Rudolf-Virchow-Zentrum für Experimentelle Biomedizin, Universität Würzburg, 97080 Würzburg, Germany
| | - Thomas Jank
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Carola Hunte
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
- CIBSS–Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Klaus Aktories
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
- Corresponding author.
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Genth H, Junemann J, Lämmerhirt CM, Lücke AC, Schelle I, Just I, Gerhard R, Pich A. Difference in Mono-O-Glucosylation of Ras Subtype GTPases Between Toxin A and Toxin B From Clostridioides difficile Strain 10463 and Lethal Toxin From Clostridium sordellii Strain 6018. Front Microbiol 2018; 9:3078. [PMID: 30622517 PMCID: PMC6308379 DOI: 10.3389/fmicb.2018.03078] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 11/29/2018] [Indexed: 12/18/2022] Open
Abstract
Clostridioides difficile toxin A (TcdA) and Toxin B (TcdB) trigger inflammasome activation with caspase-1 activation in cultured cells, which in turn induce the release of IL-6, IFN-γ, and IL-8. Release of these proinflammatory responses is positively regulated by Ras-GTPases, which leads to the hypothesis that Ras glucosylation by glucosylating toxins results in (at least) reduced proinflammatory responses. Against this background, data on toxin-catalyzed Ras glucosylation are required to estimate of pro-inflammatory effect of the glucosylating toxins. In this study, a quantitative evaluation of the GTPase substrate profiles glucosylated in human colonic (Caco-2) cells treated with either TcdA, TcdB, or the related Clostridium sordellii lethal toxin (TcsL) was performed using multiple reaction monitoring (MRM) mass spectrometry. (H/K/N)Ras are presented to be glucosylated by TcsL and TcdA but by neither TcdB isoform tested. Furthermore, the glucosylation of (H/K/N)Ras was detected in TcdA-(not TcdB)-treated cells, as analyzed exploiting immunoblot analysis using the Ras glucosylation-sensitive 27H5 antibody. Furthermore, [14C]glucosylation of substrate GTPase was found to be increased in a cell-free system complemented with Caco-2 lysates. Under these conditions, (H/K/N)Ras glucosylation by TcdA was detected. In contrast, TcdB-catalyzed (H/K/N)Ras glucosylation was detected by neither MRM analysis, immunoblot analysis nor [14C]glucosylation in a cell-free system. The observation that TcdA (not TcdB) glucosylates Ras subtype GTPases correlates with the fact that TcdB (not TcdA) is primarily responsible for inflammatory responses in CDI. Finally, TcsL more efficaciously glucosylated Ras subtype GTPase as compared with TcdA, reinforcing the paradigm that TcsL is the prototype of a Ras glucosylating toxin.
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Affiliation(s)
- Harald Genth
- Institute of Toxicology, Hannover Medical School, Hanover, Germany
| | | | | | | | - Ilona Schelle
- Institute of Toxicology, Hannover Medical School, Hanover, Germany
| | - Ingo Just
- Institute of Toxicology, Hannover Medical School, Hanover, Germany
| | - Ralf Gerhard
- Institute of Toxicology, Hannover Medical School, Hanover, Germany
| | - Andreas Pich
- Institute of Toxicology, Hannover Medical School, Hanover, Germany
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Role of p38 alpha/beta MAP Kinase in Cell Susceptibility to Clostridium sordellii Lethal Toxin and Clostridium difficile Toxin B. Toxins (Basel) 2016; 9:toxins9010002. [PMID: 28025502 PMCID: PMC5308236 DOI: 10.3390/toxins9010002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 12/16/2016] [Accepted: 12/19/2016] [Indexed: 12/27/2022] Open
Abstract
Lethal Toxin from Clostridium sordellii (TcsL), which is casually involved in the toxic shock syndrome and in gas gangrene, enters its target cells by receptor-mediated endocytosis. Inside the cell, TcsL mono-O-glucosylates and thereby inactivates Rac/Cdc42 and Ras subtype GTPases, resulting in actin reorganization and an activation of p38 MAP kinase. While a role of p38 MAP kinase in TcsL-induced cell death is well established, data on a role of p38 MAP kinase in TcsL-induced actin reorganization are not available. In this study, TcsL-induced Rac/Cdc42 glucosylation and actin reorganization are differentially analyzed in p38alpha−/− MSCV empty vector MEFs and the corresponding cell line with reconstituted p38alpha expression (p38alpha−/− MSCV p38alpha MEFs). Genetic deletion of p38alpha results in reduced susceptibility of cells to TcsL-induced Rac/Cdc42 glucosylation and actin reorganization. Furthermore, SB203580, a pyridinyl imidazole inhibitor of p38alpha/beta MAP kinase, also protects cells from TcsL-induced effects in both p38−/− MSCV empty vector MEFs and in p38alpha−/− MSCV p38alpha MEFs, suggesting that inhibition of p38beta contributes to the protective effect of SB203580. In contrast, the effects of the related C. difficile Toxin B are responsive neither to SB203580 treatment nor to p38alpha deletion. In conclusion, the protective effects of SB203580 and of p38alpha deletion are likely not based on inhibition of the toxins’ glucosyltransferase activity rather than on inhibited endocytic uptake of specifically TcsL into target cells.
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