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Pourliotopoulou E, Karampatakis T, Kachrimanidou M. Exploring the Toxin-Mediated Mechanisms in Clostridioides difficile Infection. Microorganisms 2024; 12:1004. [PMID: 38792835 PMCID: PMC11124097 DOI: 10.3390/microorganisms12051004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
Clostridioides difficile infection (CDI) is the leading cause of nosocomial antibiotic-associated diarrhea, and colitis, with increasing incidence and healthcare costs. Its pathogenesis is primarily driven by toxins produced by the bacterium C. difficile, Toxin A (TcdA) and Toxin B (TcdB). Certain strains produce an additional toxin, the C. difficile transferase (CDT), which further enhances the virulence and pathogenicity of C. difficile. These toxins disrupt colonic epithelial barrier integrity, and induce inflammation and cellular damage, leading to CDI symptoms. Significant progress has been made in the past decade in elucidating the molecular mechanisms of TcdA, TcdB, and CDT, which provide insights into the management of CDI and the future development of novel treatment strategies based on anti-toxin therapies. While antibiotics are common treatments, high recurrence rates necessitate alternative therapies. Bezlotoxumab, targeting TcdB, is the only available anti-toxin, yet limitations persist, prompting ongoing research. This review highlights the current knowledge of the structure and mechanism of action of C. difficile toxins and their role in disease. By comprehensively describing the toxin-mediated mechanisms, this review provides insights for the future development of novel treatment strategies and the management of CDI.
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Affiliation(s)
- Evdokia Pourliotopoulou
- Department of Microbiology, Medical School, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;
| | | | - Melania Kachrimanidou
- Department of Microbiology, Medical School, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;
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Kinsolving J, Bous J, Kozielewicz P, Košenina S, Shekhani R, Grätz L, Masuyer G, Wang Y, Stenmark P, Dong M, Schulte G. Structural and functional insight into the interaction of Clostridioides difficile toxin B and FZD 7. Cell Rep 2024; 43:113727. [PMID: 38308843 DOI: 10.1016/j.celrep.2024.113727] [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: 09/25/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 02/05/2024] Open
Abstract
The G protein-coupled receptors of the Frizzled (FZD) family, in particular FZD1,2,7, are receptors that are exploited by Clostridioides difficile toxin B (TcdB), the major virulence factor responsible for pathogenesis associated with Clostridioides difficile infection. We employ a live-cell assay examining the affinity between full-length FZDs and TcdB. Moreover, we present cryoelectron microscopy structures of TcdB alone and in complex with full-length FZD7, which reveal that large structural rearrangements of the combined repetitive polypeptide domain are required for interaction with FZDs and other TcdB receptors, constituting a first step for receptor recognition. Furthermore, we show that bezlotoxumab, an FDA-approved monoclonal antibody to treat Clostridioides difficile infection, favors the apo-TcdB structure and thus disrupts binding with FZD7. The dynamic transition between the two conformations of TcdB also governs the stability of the pore-forming region. Thus, our work provides structural and functional insight into how conformational dynamics of TcdB determine receptor binding.
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Affiliation(s)
- Julia Kinsolving
- Karolinska Institutet, Department Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, 17165 Stockholm, Sweden
| | - Julien Bous
- Karolinska Institutet, Department Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, 17165 Stockholm, Sweden
| | - Pawel Kozielewicz
- Karolinska Institutet, Department Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, 17165 Stockholm, Sweden
| | - Sara Košenina
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Rawan Shekhani
- Karolinska Institutet, Department Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, 17165 Stockholm, Sweden
| | - Lukas Grätz
- Karolinska Institutet, Department Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, 17165 Stockholm, Sweden
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Yuankai Wang
- Department of Urology, Boston Children's Hospital, Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Min Dong
- Department of Urology, Boston Children's Hospital, Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Gunnar Schulte
- Karolinska Institutet, Department Physiology & Pharmacology, Sec. Receptor Biology & Signaling, Biomedicum, 17165 Stockholm, Sweden.
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Papatheodorou P, Minton NP, Aktories K, Barth H. An Updated View on the Cellular Uptake and Mode-of-Action of Clostridioides difficile Toxins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1435:219-247. [PMID: 38175478 DOI: 10.1007/978-3-031-42108-2_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Research on the human gut pathogen Clostridioides (C.) difficile and its toxins continues to attract much attention as a consequence of the threat to human health posed by hypervirulent strains. Toxin A (TcdA) and Toxin B (TcdB) are the two major virulence determinants of C. difficile. Both are single-chain proteins with a similar multidomain architecture. Certain hypervirulent C. difficile strains also produce a third toxin, namely binary toxin CDT (C. difficile transferase). C. difficile toxins are the causative agents of C. difficile-associated diseases (CDADs), such as antibiotics-associated diarrhea and pseudomembranous colitis. For that reason, considerable efforts have been expended to unravel their molecular mode-of-action and the cellular mechanisms responsible for their uptake. Many of these studies have been conducted in European laboratories. Here, we provide an update on our previous review (Papatheodorou et al. Adv Exp Med Biol, 2018) on important advances in C. difficile toxins research.
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Affiliation(s)
- Panagiotis Papatheodorou
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany.
| | - Nigel P Minton
- BBSRC/EPSRC Synthetic Biology Research Centre, University of Nottingham, Nottingham, UK
| | - Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - Holger Barth
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany
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Lin Q, Li Z, Ke H, Fei J, Zhang T, Wang P, Chen Y. Linked mutations within the pathogenicity locus of Clostridioides difficile increase virulence. Infect Dis (Lond) 2023; 55:847-856. [PMID: 37615633 DOI: 10.1080/23744235.2023.2249551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/14/2023] [Indexed: 08/25/2023] Open
Abstract
BACKGROUND The clinical manifestations of Clostridioides difficile infections range from diarrhoea to pseudomembranous colitis (PMC) and death. We evaluated the association between gene content in C. difficile clinical isolates and disease severity. METHODS Fifty-three C. difficile isolates were subjected to Sanger sequencing, clinical data were used to analyse the association of gene content with disease severity, and 83 non-duplicate isolates were collected to confirm the results. Virulence was further examined by functional in vitro and in vivo experiments. RESULTS Among the 53 C. difficile isolates, ribotypes 017 (n = 9, 17.0%) and 012 (n = 8, 15.1%) were predominant. Fifteen strains exhibited a correlation between mutations of pathogenicity locus genes (tcdB, tcdC, tcdR, and tcdE) and were named linked-mutation strains. Ribotypes are not associated with clinical PMC and Linked-mutation strains. The proportion of patients with PMC was higher in the group infected with linked-mutation strains than in the non-linked-mutation group (57.14% vs. 0%, p < 0.001). The linked-mutation rate of C. difficile was higher in patients with PMC than in patients without PMC (89.47% vs. 7.8%, p < 0.0001). Linked-mutation strains showed greater cytotoxicity in vitro and caused more severe tissue damage in a mouse model. CONCLUSIONS Linked-mutation strains are associated with high virulence and PMC development. This result will help monitor the clinical prognosis of C. difficile infection and provide key insights for developing therapeutic targets and monoclonal antibodies.
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Affiliation(s)
- Qianyun Lin
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zitong Li
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Haoran Ke
- Hepatology Unit, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jiaxi Fei
- Graceland Medical Center, the, Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ting Zhang
- Department of Gastroenterology, the Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Pu Wang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ye Chen
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Integrative Microecology Center, Department of Gastroenterology, Shenzhen Hospital, Southern Medical University, Shenzhen, China
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Fettucciari K, Dini F, Marconi P, Bassotti G. Role of the Alteration in Calcium Homeostasis in Cell Death Induced by Clostridioides difficile Toxin A and Toxin B. BIOLOGY 2023; 12:1117. [PMID: 37627001 PMCID: PMC10452684 DOI: 10.3390/biology12081117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 08/05/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023]
Abstract
Clostridioides difficile (C. difficile), responsible for 15-25% of gastrointestinal infections, causes health problems mainly due to the toxic activity of toxins A and B (Tcds). These are responsible for its clinical manifestations, including diarrhea, pseudomembranous colitis, toxic megacolon and death, with a mortality of 5-30% in primary infection, that increase following relapses. Studies on Tcd-induced cell death have highlighted a key role of caspases, calpains, and cathepsins, with involvement of mitochondria and reactive oxygen species (ROS) in a complex signaling pathway network. The complex response in the execution of various types of cell death (apoptosis, necrosis, pyroptosis and pyknosis) depends on the amount of Tcd, cell types, and Tcd receptors involved, and could have as initial/precocious event the alterations in calcium homeostasis. The entities, peculiarities and cell types involved in these alterations will decide the signaling pathways activated and cell death type. Calcium homeostasis alterations can be caused by calcium influx through calcium channel activation, transient intracellular calcium oscillations, and leakage of calcium from intracellular stores. These increases in cytoplasmic calcium have important effects on all calcium-regulated molecules, which may play a direct role in several cell death types and/or activate other cell death effectors, such as caspases, calpains, ROS and proapoptotic Bcl-2 family members. Furthermore, some support for the possible role of the calcium homeostasis alteration in Tcd-induced cell death originates from the similarity with cytotoxic effects that cause pore-forming toxins, based mainly on calcium influx through plasma membrane pores.
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Affiliation(s)
- Katia Fettucciari
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy;
| | - Fabrizio Dini
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024 Matelica, Italy;
| | - Pierfrancesco Marconi
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy;
| | - Gabrio Bassotti
- Gastroenterology, Hepatology & Digestive Endoscopy Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy;
- Gastroenterology & Hepatology Unit, Santa Maria Della Misericordia Hospital, 06129 Perugia, Italy
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Tian S, Zhou N. Gaining New Insights into Fundamental Biological Pathways by Bacterial Toxin-Based Genetic Screens. Bioengineering (Basel) 2023; 10:884. [PMID: 37627769 PMCID: PMC10451959 DOI: 10.3390/bioengineering10080884] [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: 05/15/2023] [Revised: 07/11/2023] [Accepted: 07/22/2023] [Indexed: 08/27/2023] Open
Abstract
Genetic screen technology has been applied to study the mechanism of action of bacterial toxins-a special class of virulence factors that contribute to the pathogenesis caused by bacterial infections. These screens aim to identify host factors that directly or indirectly facilitate toxin intoxication. Additionally, specific properties of certain toxins, such as membrane interaction, retrograde trafficking, and carbohydrate binding, provide robust probes to comprehensively investigate the lipid biosynthesis, membrane vesicle transport, and glycosylation pathways, respectively. This review specifically focuses on recent representative toxin-based genetic screens that have identified new players involved in and provided new insights into fundamental biological pathways, such as glycosphingolipid biosynthesis, protein glycosylation, and membrane vesicle trafficking pathways. Functionally characterizing these newly identified factors not only expands our current understanding of toxin biology but also enables a deeper comprehension of fundamental biological questions. Consequently, it stimulates the development of new therapeutic approaches targeting both bacterial infectious diseases and genetic disorders with defects in these factors and pathways.
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Affiliation(s)
- Songhai Tian
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
- Department of Urology, Boston Children’s Hospital, Boston, MA 02115, USA;
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Nini Zhou
- Department of Urology, Boston Children’s Hospital, Boston, MA 02115, USA;
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
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7
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Fettucciari K, Fruganti A, Stracci F, Spaterna A, Marconi P, Bassotti G. Clostridioides difficile Toxin B Induced Senescence: A New Pathologic Player for Colorectal Cancer? Int J Mol Sci 2023; 24:ijms24098155. [PMID: 37175861 PMCID: PMC10179142 DOI: 10.3390/ijms24098155] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/26/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Clostridioides difficile (C. difficile) is responsible for a high percentage of gastrointestinal infections and its pathological activity is due to toxins A and B. C. difficile infection (CDI) is increasing worldwide due to the unstoppable spread of C. difficile in the anthropized environment and the progressive human colonization. The ability of C. difficile toxin B to induce senescent cells and the direct correlation between CDI, irritable bowel syndrome (IBS), and inflammatory bowel diseases (IBD) could cause an accumulation of senescent cells with important functional consequences. Furthermore, these senescent cells characterized by long survival could push pre-neoplastic cells originating in the colon towards the complete neoplastic transformation in colorectal cancer (CRC) by the senescence-associated secretory phenotype (SASP). Pre-neoplastic cells could appear as a result of various pro-carcinogenic events, among which, are infections with bacteria that produce genotoxins that generate cells with high genetic instability. Therefore, subjects who develop IBS and/or IBD after CDI should be monitored, especially if they then have further CDI relapses, waiting for the availability of senolytic and anti-SASP therapies to resolve the pro-carcinogenic risk due to accumulation of senescent cells after CDI followed by IBS and/or IBD.
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Affiliation(s)
- Katia Fettucciari
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy
| | - Alessandro Fruganti
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024 Matelica, Italy
| | - Fabrizio Stracci
- Public Health Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy
| | - Andrea Spaterna
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024 Matelica, Italy
| | - Pierfrancesco Marconi
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy
| | - Gabrio Bassotti
- Gastroenterology, Hepatology & Digestive Endoscopy Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy
- Gastroenterology & Hepatology Unit, Santa Maria Della Misericordia Hospital, 06129 Perugia, Italy
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Ok MT, Liu J, Bliton RJ, Hinesley CM, San Pedro EET, Breau KA, Gomez-Martinez I, Burclaff J, Magness ST. A leaky human colon model reveals uncoupled apical/basal cytotoxicity in early Clostridioides difficile toxin exposure. Am J Physiol Gastrointest Liver Physiol 2023; 324:G262-G280. [PMID: 36749911 PMCID: PMC10010926 DOI: 10.1152/ajpgi.00251.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/31/2023] [Accepted: 02/05/2023] [Indexed: 02/09/2023]
Abstract
Clostridioides difficile (C. difficile) toxins A (TcdA) and B (TcdB) cause antibiotic-associated colitis in part by disrupting epithelial barrier function. Accurate in vitro models are necessary to detect early toxicity kinetics, investigate disease etiology, and develop preclinical models for new therapies. Properties of cancer cell lines and organoids inherently limit these efforts. We developed adult stem cell-derived monolayers of differentiated human colonic epithelium (hCE) with barrier function, investigated the impact of toxins on apical/basal aspects of monolayers, and evaluated whether a leaky epithelial barrier enhances toxicity. Single-cell RNA-sequencing (scRNAseq) mapped C. difficile-relevant genes to human lineages. Transcriptomics compared hCE to Caco-2, informed timing of in vitro stem cell differentiation, and revealed transcriptional responses to TcdA. Transepithelial electrical resistance (TEER) and fluorescent permeability assays measured cytotoxicity. Contribution of TcdB toxicity was evaluated in a diclofenac-induced leaky gut model. scRNAseq demonstrated broad and variable toxin receptor expression. Absorptive colonocytes in vivo displayed increased toxin receptor, Rho GTPase, and cell junction gene expression. Advanced TcdA toxicity generally decreased cytokine/chemokine and increased tight junction and death receptor genes. Differentiated Caco-2 cells remained immature whereas hCE monolayers were similar to mature colonocytes in vivo. Basal exposure of TcdA/B caused greater toxicity and apoptosis than apical exposure. Apical exposure to toxins was enhanced by diclofenac. Apical/basal toxicities are uncoupled with more rapid onset and increased magnitude postbasal toxin exposure. Leaky junctions enhance toxicity of apical TcdB exposure. hCE monolayers represent a physiologically relevant and sensitive system to evaluate the impact of microbial toxins on gut epithelium.NEW & NOTEWORTHY Novel human colonocyte monolayer cultures, benchmarked by transcriptomics for physiological relevance, detect early cytopathic impacts of Clostridioides difficile toxins TcdA and TcdB. A fluorescent ZO-1 reporter in primary human colonocytes is used to track epithelial barrier disruption in response to TcdA. Basal TcdA/B exposure generally caused more rapid onset and cytotoxicity than apical exposure. Transcriptomics demonstrate changes in tight junction, chemokine, and cytokine receptor gene expression post-TcdA exposure. Diclofenac-induced leaky epithelium enhanced apical exposure toxicity.
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Affiliation(s)
- Meryem T Ok
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States
| | - Jintong Liu
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States
| | - R Jarrett Bliton
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States
| | - Caroline M Hinesley
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States
| | - Ekaterina Ellyce T San Pedro
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States
| | - Keith A Breau
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Ismael Gomez-Martinez
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Joseph Burclaff
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States
| | - Scott T Magness
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina, United States
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
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9
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Csukovich G, Kramer N, Pratscher B, Gotic I, Freund P, Hahn R, Himmler G, Brandt S, Burgener IA. Neutralising Effects of Different Antibodies on Clostridioides difficile Toxins TcdA and TcdB in a Translational Approach. Int J Mol Sci 2023; 24:ijms24043867. [PMID: 36835278 PMCID: PMC9962434 DOI: 10.3390/ijms24043867] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/30/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Given the high prevalence of intestinal disease in humans and animals, there is a strong need for clinically relevant models recapitulating gastrointestinal systems, ideally replacing in vivo models in accordance with the principles of the 3R. We established a canine organoid system and analysed the neutralising effects of recombinant versus natural antibodies on Clostridioides difficile toxins A and B in this in vitro system. Sulforhodamine B cytotoxicity assays in 2D and FITC-dextran barrier integrity assays on basal-out and apical-out organoids revealed that recombinant, but not natural antibodies, effectively neutralised C. difficile toxins. Our findings emphasise that canine intestinal organoids can be used to test different components and suggest that they can be further refined to also mirror complex interactions between the intestinal epithelium and other cells.
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Affiliation(s)
- Georg Csukovich
- Small Animal Internal Medicine, Department for Companion Animals and Horses, Vetmeduni, 1210 Vienna, Austria
| | - Nina Kramer
- Small Animal Internal Medicine, Department for Companion Animals and Horses, Vetmeduni, 1210 Vienna, Austria
| | - Barbara Pratscher
- Small Animal Internal Medicine, Department for Companion Animals and Horses, Vetmeduni, 1210 Vienna, Austria
| | | | - Patricia Freund
- Small Animal Internal Medicine, Department for Companion Animals and Horses, Vetmeduni, 1210 Vienna, Austria
| | - Rainer Hahn
- Department for Biotechnology, University of Natural Resources and Life Sciences Vienna, 1190 Vienna, Austria
| | | | - Sabine Brandt
- Research Group Oncology (RGO), Clinical Unit of Equine Surgery, Department for Companion Animals and Horses, Vetmeduni, 1210 Vienna, Austria
| | - Iwan Anton Burgener
- Small Animal Internal Medicine, Department for Companion Animals and Horses, Vetmeduni, 1210 Vienna, Austria
- Correspondence:
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10
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Chen P, Jin R. Receptor binding mechanisms of Clostridioides difficile toxin B and implications for therapeutics development. FEBS J 2023; 290:962-969. [PMID: 34862749 PMCID: PMC9344982 DOI: 10.1111/febs.16310] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/19/2021] [Accepted: 12/02/2021] [Indexed: 12/29/2022]
Abstract
Clostridioides difficile is classified as an urgent antibiotic resistance threat by the Centers for Disease Control and Prevention (CDC). C. difficile infection (CDI) is mainly caused by the C. difficile exotoxin TcdB, which invades host cells via receptor-mediated endocytosis. However, many natural variants of TcdB have been identified including some from the hypervirulent strains, which pose significant challenges for developing effective CDI therapies. Here, we review the recent research progress on the molecular mechanisms by which TcdB recognizes Frizzed proteins (FZDs) and chondroitin sulfate proteoglycan 4 (CSPG4) as two major host receptors. We suggest that the receptor-binding sites and several previously identified neutralizing epitopes on TcdB are ideal targets for the development of broad-spectrum inhibitors to protect against diverse TcdB variants.
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Affiliation(s)
- Peng Chen
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, 92697, USA
| | - Rongsheng Jin
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, 92697, USA
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11
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Bassotti G, Fruganti A, Stracci F, Marconi P, Fettucciari K. Cytotoxic synergism of Clostridioides difficile toxin B with proinflammatory cytokines in subjects with inflammatory bowel diseases. World J Gastroenterol 2023; 29:582-596. [PMID: 36742168 PMCID: PMC9896618 DOI: 10.3748/wjg.v29.i4.582] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/03/2022] [Accepted: 12/27/2022] [Indexed: 01/20/2023] Open
Abstract
Clostridioides difficile (C. difficile) is progressively colonizing humans and animals living with humans. During this process, hypervirulent strains and mutated toxin A and B of C. difficile (TcdA and TcdB) are originating and developing. While in healthy subjects colonization by C. difficile becomes a risk after the use of antibiotics that alter the microbiome, other categories of people are more susceptible to infection and at risk of relapse, such as those with inflammatory bowel disease (IBD). Recent in vitro studies suggest that this increased susceptibility could be due to the strong cytotoxic synergism between TcdB and proinflammatory cytokines the tumor necrosis factor-alpha and interferon-gamma (CKs). Therefore, in subjects with IBD the presence of an inflammatory state in the colon could be the driver that increases the susceptibility to C. difficile infection and its progression and relapses. TcdB is internalized in the cell via three receptors: chondroitin sulphate proteoglycan 4; poliovirus receptor-like 3; and Wnt receptor frizzled family. Chondroitin sulphate proteoglycan 4 and Wnt receptor frizzled family are involved in cell death by apoptosis or necrosis depending on the concentration of TcdB and cell types, while poliovirus receptor-like 3 induces only necrosis. It is possible that cytokines could also induce a greater expression of receptors for TcdB that are more involved in necrosis than in apoptosis. Therefore, in subjects with IBD there are the conditions: (1) For greater susceptibility to C. difficile infection, such as the inflammatory state, and abnormalities of the microbiome and of the immune system; (2) for the enhancement of the cytotoxic activity of TcdB +Cks; and (3) for a greater expression of TcdB receptors stimulated by cytokines that induce cell death by necrosis rather than apoptosis. The only therapeutic approach currently possible in IBD patients is monitoring of C. difficile colonization for interventions aimed at reducing tumor necrosis factor-alpha and interferon-gamma levels when the infection begins. The future perspective is to generate bacteriophages against C. difficile for targeted therapy.
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Affiliation(s)
- Gabrio Bassotti
- Department of Medicine and Surgery, Gastroenterology, Hepatology & Digestive Endoscopy Section University of Perugia Medical School, Piazza Lucio Severi, Perugia 06132, Italy, and Santa Maria della Misericordia Hospital, Gastroenterology & Hepatology Unit Perugia 06156, Italy
| | - Alessandro Fruganti
- School of Biosciences and Veterinary Medicine, University of Camerino, Matelica 62024, Italy
| | - Fabrizio Stracci
- Medicine and Surgery, Hygiene and Public Health Section, University of Perugia, Perugia 06123, Italy
| | - Pierfrancesco Marconi
- Medicine and Surgery, Biosciences & Medical Embryology Section, University of Perugia, Perugia 06132, Italy
| | - Katia Fettucciari
- Medicine and Surgery, Biosciences & Medical Embryology Section, University of Perugia, Perugia 06132, Italy
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12
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Alamri MA, Tariq MH, Tahir Ul Qamar M, Alabbas AB, Alqahtani SM, Ahmad S. Discovery of potential phytochemicals as inhibitors of TcdB, a major virulence factors of Clostridioides difficile. J Biomol Struct Dyn 2023; 41:12768-12776. [PMID: 36644848 DOI: 10.1080/07391102.2023.2167120] [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: 08/17/2022] [Accepted: 01/06/2023] [Indexed: 01/17/2023]
Abstract
Clostridioides difficile is a gram-positive bacterium which is associated with different gastrointestinal related infections, and the numbers of cases related to it are continuously increasing in the past few years. Owing to high prevalence and development of resistance towards available antibiotics, it is required to develop new therapeutics to combat C. difficile infection. The current study was aimed to identify novel phytochemicals that could bind and inhibits the TcdB, an exotoxin which is required for the pathogenesis of bacteria, and hence can be considered as the future drug candidates against C. difficile. ∼2500 therapeutically important phyto-compounds were docked against the active sites of TcdB protein by using AutoDock-Vina software. The interactions between the ligands and the binding site of the top five docked complexes, based on the docking scores, were further elucidated by Molecular Dynamics Simulations of 500 ns, Molecular Mechanics Energies combined with the Poisson-Boltzmann and Surface Area (MMPBSA) or Generalized Born and Surface Area (MMGBSA), and WaterSwap Analysis. Findings of molecular docking suggested that natural compounds A183, A704, A1528, A2083, and A2129 with distinct chemical scaffolds are best docked in the binding site of TcdB and their bonding remained stable throughout the simulation studies of 500 ns. Compounds A2129 and A704 can be considered as prospective drug candidates against Clostridioides difficile, however, further wet lab experiments are needed to confirm our study.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Mubarak A Alamri
- Department of Pharmaceutical Chemistry, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | | | - Muhammad Tahir Ul Qamar
- Integrative Omics and Molecular Modeling Laboratory, Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Alhumaidi B Alabbas
- Department of Pharmaceutical Chemistry, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Safar M Alqahtani
- Department of Pharmaceutical Chemistry, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Sajjad Ahmad
- Department of Health and Biological Sciences, Abasyn University, Peshawar, Pakistan
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13
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Tian S, Xiong X, Zeng J, Wang S, Tremblay BJM, Chen P, Chen B, Liu M, Chen P, Sheng K, Zeve D, Qi W, Breault DT, Rodríguez C, Gerhard R, Jin R, Doxey AC, Dong M. Identification of TFPI as a receptor reveals recombination-driven receptor switching in Clostridioides difficile toxin B variants. Nat Commun 2022; 13:6786. [PMID: 36351897 PMCID: PMC9646764 DOI: 10.1038/s41467-022-33964-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 10/10/2022] [Indexed: 11/11/2022] Open
Abstract
Toxin B (TcdB) is a major exotoxin responsible for diseases associated with Clostridioides difficile infection. Its sequence variations among clinical isolates may contribute to the difficulty in developing effective therapeutics. Here, we investigate receptor-binding specificity of major TcdB subtypes (TcdB1 to TcdB12). We find that representative members of subtypes 2, 4, 7, 10, 11, and 12 do not recognize the established host receptor, frizzled proteins (FZDs). Using a genome-wide CRISPR-Cas9-mediated screen, we identify tissue factor pathway inhibitor (TFPI) as a host receptor for TcdB4. TFPI is recognized by a region in TcdB4 that is homologous to the FZD-binding site in TcdB1. Analysis of 206 TcdB variant sequences reveals a set of six residues within this receptor-binding site that defines a TFPI binding-associated haplotype (designated B4/B7) that is present in all TcdB4 members, a subset of TcdB7, and one member of TcdB2. Intragenic micro-recombination (IR) events have occurred around this receptor-binding region in TcdB7 and TcdB2 members, resulting in either TFPI- or FZD-binding capabilities. Introduction of B4/B7-haplotype residues into TcdB1 enables dual recognition of TFPI and FZDs. Finally, TcdB10 also recognizes TFPI, although it does not belong to the B4/B7 haplotype, and shows species selectivity: it recognizes TFPI of chicken and to a lesser degree mouse, but not human, dog, or cattle versions. These findings identify TFPI as a TcdB receptor and reveal IR-driven changes on receptor-specificity among TcdB variants.
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Affiliation(s)
- Songhai Tian
- Department of Urology, Boston Children's Hospital, Boston, MA, 02115, USA.
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA, 02115, USA.
| | - Xiaozhe Xiong
- Department of Urology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA, 02115, USA
| | - Ji Zeng
- Department of Urology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA, 02115, USA
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Siyu Wang
- Department of Urology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA, 02115, USA
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310016, China
| | - Benjamin Jean-Marie Tremblay
- Department of Biology, Cheriton School of Computer Science, and Waterloo Centre for Microbial Research, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Peng Chen
- Department of Physiology and Biophysics, School of Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - Baohua Chen
- Department of Physiology and Biophysics, School of Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - Min Liu
- Department of Urology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA, 02115, USA
| | - Pengsheng Chen
- Department of Urology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA, 02115, USA
| | - Kuanwei Sheng
- Wyss Institute for Bioinspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Daniel Zeve
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | - Wanshu Qi
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | - David T Breault
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
- Harvard Stem Cell Institute, 7 Divinity Avenue, Cambridge, MA, 02138, USA
| | - César Rodríguez
- Faculty of Microbiology & CIET, University of Costa Rica, San José, Costa Rica
| | - Ralf Gerhard
- Institute of Toxicology, Hannover Medical School, 30625, Hannover, Germany
| | - Rongsheng Jin
- Department of Physiology and Biophysics, School of Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - Andrew C Doxey
- Department of Biology, Cheriton School of Computer Science, and Waterloo Centre for Microbial Research, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
| | - Min Dong
- Department of Urology, Boston Children's Hospital, Boston, MA, 02115, USA.
- Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA, 02115, USA.
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14
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Plakoglobin and High-Mobility Group Box 1 Mediate Intestinal Epithelial Cell Apoptosis Induced by Clostridioides difficile TcdB. mBio 2022; 13:e0184922. [PMID: 36043787 DOI: 10.1128/mbio.01849-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridioides difficile infection (CDI) is the leading cause of antibiotic-associated intestinal disease, resulting in severe diarrhea and fatal pseudomembranous colitis. TcdB, one of the essential virulence factors secreted by this bacterium, induces host cell apoptosis through a poorly understood mechanism. Here, we performed an RNA interference (RNAi) screen customized to Caco-2 cells, a cell line model of the intestinal epithelium, to discover host factors involved in TcdB-induced apoptosis. We identified plakoglobin, also known as junction plakoglobin (JUP) or γ-catenin, a member of the catenin family, as a novel host factor and a previously known cell death-related chromatin factor, high-mobility group box 1 (HMGB1). Disruption of those host factors by RNAi and CRISPR resulted in resistance of cells to TcdB-mediated and mitochondrion-dependent apoptosis. JUP was redistributed from adherens junctions to the mitochondria and colocalized with the antiapoptotic factor Bcl-XL. JUP proteins could permeabilize the mitochondrial membrane, resulting in the release of cytochrome c. Our results reveal a novel role of JUP in targeting the mitochondria to promote the mitochondrial apoptotic pathway. Treatment with glycyrrhizin, an HMGB1 inhibitor, resulted in significantly increased resistance to TcdB-induced epithelial damage in cultured cells and a mouse ligated colon loop model. These findings demonstrate the critical roles of JUP and HMGB1 in TcdB-induced epithelial cell apoptosis. IMPORTANCE Clostridioides difficile infection (CDI) is the leading cause of hospital-acquired diarrhea. Toxins, especially TcdB, cause epithelial cell apoptosis, but the underlying cell death mechanism is less clear. Through an apoptosis-focused RNAi screen using a bacterium-made small interfering (siRNA) library customized to a human colonic epithelial cell model, we found a novel host factor, plakoglobin (γ-catenin), as a key factor required for cell apoptosis induced by TcdB. Plakoglobin targets and permeabilizes mitochondria after stimulation by TcdB, demonstrating a hitherto underappreciated role of this catenin family member in the apoptosis of intestinal epithelial cells. We also found a previously known cell death-related chromatin factor, HMGB1, and explored the inhibition of HMGB1 for CDI therapy in vivo.
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15
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Luo J, Yang Q, Zhang X, Zhang Y, Wan L, Zhan X, Zhou Y, He L, Li D, Jin D, Zhen Y, Huang J, Li Y, Tao L. TFPI is a colonic crypt receptor for TcdB from hypervirulent clade 2 C. difficile. Cell 2022; 185:980-994.e15. [PMID: 35303428 DOI: 10.1016/j.cell.2022.02.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 01/11/2022] [Accepted: 02/08/2022] [Indexed: 12/14/2022]
Abstract
The emergence of hypervirulent clade 2 Clostridioides difficile is associated with severe symptoms and accounts for >20% of global infections. TcdB is a dominant virulence factor of C. difficile, and clade 2 strains exclusively express two TcdB variants (TcdB2 and TcdB4) that use unknown receptors distinct from the classic TcdB. Here, we performed CRISPR/Cas9 screens for TcdB4 and identified tissue factor pathway inhibitor (TFPI) as its receptor. Using cryo-EM, we determined a complex structure of the full-length TcdB4 with TFPI, defining a common receptor-binding region for TcdB. Residue variations within this region divide major TcdB variants into 2 classes: one recognizes Frizzled (FZD), and the other recognizes TFPI. TFPI is highly expressed in the intestinal glands, and recombinant TFPI protects the colonic epithelium from TcdB2/4. These findings establish TFPI as a colonic crypt receptor for TcdB from clade 2 C. difficile and reveal new mechanisms for CDI pathogenesis.
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Affiliation(s)
- Jianhua Luo
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Qi Yang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Xiaofeng Zhang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yuanyuan Zhang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China; School of Food Science and Biotechnology Engineering, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, China
| | - Li Wan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Xiechao Zhan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yao Zhou
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Liuqing He
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Danyang Li
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Dazhi Jin
- Center of Laboratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, China; School of Laboratory Medicine, Hangzhou Medical College, Hangzhou, Zhejiang 310014, China
| | - Ying Zhen
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Jing Huang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yanyan Li
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China.
| | - Liang Tao
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China.
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16
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Jiang M, Shin J, Simeon R, Chang JY, Meng R, Wang Y, Shinde O, Li P, Chen Z, Zhang J. Structural dynamics of receptor recognition and pH-induced dissociation of full-length Clostridioides difficile Toxin B. PLoS Biol 2022; 20:e3001589. [PMID: 35324891 PMCID: PMC8982864 DOI: 10.1371/journal.pbio.3001589] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 04/05/2022] [Accepted: 03/02/2022] [Indexed: 12/14/2022] Open
Abstract
Clostridioides difficile secretes Toxin B (TcdB) as one of its major virulence factors, which binds to intestinal epithelial and subepithelial receptors, including frizzled proteins and chondroitin sulfate proteoglycan 4 (CSPG4). Here, we present cryo-EM structures of full-length TcdB in complex with the CSPG4 domain 1 fragment (D1401-560) at cytosolic pH and the cysteine-rich domain of frizzled-2 (CRD2) at both cytosolic and acidic pHs. CSPG4 specifically binds to the autoprocessing and delivery domains of TcdB via networks of salt bridges, hydrophobic and aromatic/proline interactions, which are disrupted upon acidification eventually leading to CSPG4 drastically dissociating from TcdB. In contrast, FZD2 moderately dissociates from TcdB under acidic pH, most likely due to its partial unfolding. These results reveal structural dynamics of TcdB during its preentry step upon endosomal acidification, which provide a basis for developing therapeutics against C. difficile infections.
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Affiliation(s)
- Mengqiu Jiang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Joonyoung Shin
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Rudo Simeon
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Jeng-Yih Chang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Ran Meng
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Yuhang Wang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Omkar Shinde
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Pingwei Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Zhilei Chen
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
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17
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Brauer M, Herrmann J, Zühlke D, Müller R, Riedel K, Sievers S. Myxopyronin B inhibits growth of a Fidaxomicin-resistant Clostridioides difficile isolate and interferes with toxin synthesis. Gut Pathog 2022; 14:4. [PMID: 34991700 PMCID: PMC8739712 DOI: 10.1186/s13099-021-00475-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 12/13/2021] [Indexed: 02/06/2023] Open
Abstract
The anaerobic, gastrointestinal pathogen Clostridioides difficile can cause severe forms of enterocolitis which is mainly mediated by the toxins it produces. The RNA polymerase inhibitor Fidaxomicin is the current gold standard for the therapy of C. difficile infections due to several beneficial features including its ability to suppress toxin synthesis in C. difficile. In contrast to the Rifamycins, Fidaxomicin binds to the RNA polymerase switch region, which is also the binding site for Myxopyronin B. Here, serial broth dilution assays were performed to test the susceptibility of C. difficile and other anaerobes to Myxopyronin B, proving that the natural product is considerably active against C. difficile and that there is no cross-resistance between Fidaxomicin and Myxopyronin B in a Fidaxomicin-resistant C. difficile strain. Moreover, mass spectrometry analysis indicated that Myxopyronin B is able to suppress early phase toxin synthesis in C. difficile to the same degree as Fidaxomicin. Conclusively, Myxopyronin B is proposed as a new lead structure for the design of novel antibiotics for the therapy of C. difficile infections.
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Affiliation(s)
- Madita Brauer
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Jennifer Herrmann
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS)-Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Saarbrücken, Germany.,German Center for Infection Research (DZIF), Braunschweig, Germany
| | - Daniela Zühlke
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Rolf Müller
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS)-Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Saarbrücken, Germany.,German Center for Infection Research (DZIF), Braunschweig, Germany
| | - Katharina Riedel
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Susanne Sievers
- Institute of Microbiology, University of Greifswald, Greifswald, Germany.
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18
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Klepka C, Sandmann M, Tatge H, Mangan M, Arens A, Henkel D, Gerhard R. Impairment of lysosomal function by Clostridioides difficile TcdB. Mol Microbiol 2021; 117:493-507. [PMID: 34931374 DOI: 10.1111/mmi.14864] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 11/30/2022]
Abstract
TcdB is a potent cytotoxin produced by pathogenic Clostridioides difficile that inhibits Rho GTPases by mono-glucosylation. TcdB enters cells via receptor-mediated endocytosis. The pathogenic glucosyltransferase domain (GTD) egresses endosomes by pH-mediated conformational changes, and is subsequently released in an autoproteolytic manner. We here investigated the uptake, localization and degradation of TcdB. TcdB colocalized with lysosomal marker protein LAMP1, verifying the endosomal-lysosomal route of the toxin. In pulse assays endocytosed TcdB declined to a limit of detection within 2 hr, whereas the released GTD accumulated for up to 8 hr. We observed that autoproteolytic deficient TcdB NXN C698S was degraded significantly faster than wildtype TcdB, suggesting interference of TcdB with lysosomal degradation process. In fact, TcdB reduced lysosomal degradation of endosome cargo as tested with DQ-Green BSA. Lysosomal dysfunction was accompanied by perinuclear accumulation of LAMP1 and a weaker detection in immunoblots. Galectin-8 or galectin-3 was not recruited to lysosomes speaking against lysosome membrane damage. Changes in the autophagosomal marker LC3B suggested additional indirect effect of lysosomal dysfunction on the autophagic flux. In contrast to necrotic signaling induced in by TcdB, lysosomal dysfunction was not abolished by calcium channel blocker nifedipin, indicating separate cytopathogenic effects induced by TcdB during endo-lysosomal trafficking.
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Affiliation(s)
- Carmen Klepka
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
| | - Moritz Sandmann
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
| | - Helma Tatge
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
| | - Matthew Mangan
- Institute of Innate Immunology, Biomedical Center, University of Bonn, Bonn, Germany.,German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Annabel Arens
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
| | - Daniel Henkel
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
| | - Ralf Gerhard
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
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19
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Fettucciari K, Marconi P, Marchegiani A, Fruganti A, Spaterna A, Bassotti G. Invisible steps for a global endemy: molecular strategies adopted by Clostridioides difficile. Therap Adv Gastroenterol 2021; 14:17562848211032797. [PMID: 34413901 PMCID: PMC8369858 DOI: 10.1177/17562848211032797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 06/26/2021] [Indexed: 02/06/2023] Open
Abstract
Clostridioides difficile infection (CDI) is on the rise worldwide and is associated with an increase in deaths and socio-health burden. C. difficile has become ubiquitous in anthropized environments because of the extreme resistance of its spores. Based on the epidemiological data and knowledge of molecular pathogenesis of C. difficile, it is possible to predict its progressive colonization of the human population for the following reasons: first, its global spread is unstoppable; second, the toxins (Tcds) produced by C. difficile, TcdA and TcdB, mainly cause cell death by apoptosis, but the surviving cells acquire a senescence state that favours persistence of C. difficile in the intestine; third, proinflammatory cytokines, tumour necrosis factor-α and interferon-γ, induced during CDI, enhance the cytotoxicity of Tcds and can increase the survival of senescent cells; fourth, Tcds block mobility and induce apoptosis in immune cells recruited at the infection site; and finally, after remission from primary infection or relapse, C. difficile causes functional abnormalities in the enteric glial cell (EGC) network that can result in irritable bowel syndrome, characterized by a latent inflammatory response that contributes to C. difficile survival and enhances the cytotoxic activity of low doses of TcdB, thus favouring further relapses. Since a 'global endemy' of C. difficile seems inevitable, it is necessary to develop an effective vaccine against Tcds for at-risk individuals, and to perform a prophylaxis/selective therapy with bacteriophages highly specific for C. difficile. We must be aware that CDI will become a global health problem in the forthcoming years, and we must be prepared to face this menace.
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Affiliation(s)
- Katia Fettucciari
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, Medical School -Piazza Lucio Severi 1, Edificio B - IV piano; Sant’Andrea delle Fratte, Perugia, 06132, Italy
| | - Pierfrancesco Marconi
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Andrea Marchegiani
- School of Biosciences and Veterinary Medicine, University of Camerino, Macerata, Italy
| | - Alessandro Fruganti
- School of Biosciences and Veterinary Medicine, University of Camerino, Macerata, Italy
| | - Andrea Spaterna
- School of Biosciences and Veterinary Medicine, University of Camerino, Macerata, Italy
| | - Gabrio Bassotti
- Gastroenterology, Hepatology & Digestive Endoscopy Section, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
- Gastroenterology & Hepatology Unit, Santa Maria della Misericordia Hospital, Perugia, Italy
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Chen P, Zeng J, Liu Z, Thaker H, Wang S, Tian S, Zhang J, Tao L, Gutierrez CB, Xing L, Gerhard R, Huang L, Dong M, Jin R. Structural basis for CSPG4 as a receptor for TcdB and a therapeutic target in Clostridioides difficile infection. Nat Commun 2021; 12:3748. [PMID: 34145250 PMCID: PMC8213806 DOI: 10.1038/s41467-021-23878-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 05/19/2021] [Indexed: 12/13/2022] Open
Abstract
C. difficile is a major cause of antibiotic-associated gastrointestinal infections. Two C. difficile exotoxins (TcdA and TcdB) are major virulence factors associated with these infections, and chondroitin sulfate proteoglycan 4 (CSPG4) is a potential receptor for TcdB, but its pathophysiological relevance and the molecular details that govern recognition remain unknown. Here, we determine the cryo-EM structure of a TcdB–CSPG4 complex, revealing a unique binding site spatially composed of multiple discontinuous regions across TcdB. Mutations that selectively disrupt CSPG4 binding reduce TcdB toxicity in mice, while CSPG4-knockout mice show reduced damage to colonic tissues during C. difficile infections. We further show that bezlotoxumab, the only FDA approved anti-TcdB antibody, blocks CSPG4 binding via an allosteric mechanism, but it displays low neutralizing potency on many TcdB variants from epidemic hypervirulent strains due to sequence variations in its epitopes. In contrast, a CSPG4-mimicking decoy neutralizes major TcdB variants, suggesting a strategy to develop broad-spectrum therapeutics against TcdB. Chondroitin sulfate proteoglycan 4 (CSPG4) is a potential receptor for C. difficile toxin B (TcdB) during C. difficile infections (CDIs). Here, the cryo-EM structure of a TcdB–CSPG4 complex and CDI mouse models offer insights into CSPG4 role in CDIs and suggest a therapeutic strategy targeting TcdB.
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Affiliation(s)
- Peng Chen
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA
| | - Ji Zeng
- Department of Urology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Zheng Liu
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA
| | - Hatim Thaker
- Department of Urology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Siyu Wang
- Department of Urology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA.,Department of Gastrointestinal, Colorectal and Anal Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Songhai Tian
- Department of Urology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Jie Zhang
- Department of Urology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA.,Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Liang Tao
- Center for Infectious Disease Research, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China.,Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Craig B Gutierrez
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA
| | - Li Xing
- UC Irvine Materials Research Institute (IMRI), University of California, Irvine, CA, USA
| | - Ralf Gerhard
- Institute of Toxicology, Hannover Medical School, Hannover, Germany
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA
| | - Min Dong
- Department of Urology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA. .,Department of Microbiology, Harvard Medical School, Boston, MA, USA. .,Department of Surgery, Harvard Medical School, Boston, MA, USA.
| | - Rongsheng Jin
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA.
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