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Karnchanapandh K, Sanachai K, Poo-Arporn RP, Rungrotmongkol T. Enhancing bezlotoxumab binding to C. difficile toxin B2: insights from computational simulations and mutational analyses for antibody design. J Biomol Struct Dyn 2024:1-11. [PMID: 38511411 DOI: 10.1080/07391102.2024.2329785] [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: 11/09/2023] [Accepted: 03/06/2024] [Indexed: 03/22/2024]
Abstract
Clostridioides difficile infection (CDI) is a significant concern caused by widespread antibiotic use, resulting in diarrhea and inflammation from the gram-positive anaerobic bacterium C. difficile. Although bezlotoxumab (Bez), a monoclonal antibody (mAb), was developed to address CDI recurrences, the recurrence rate remains high, partly due to reduced neutralization efficiency against toxin B2. In this study, we aimed to enhance the binding of Bez to C. difficile toxin B2 by combining computational simulations and mutational analyses. We identified specific mutations in Bez, including S28R, S31W/K, Y32R, S56W and G103D/S in the heavy chain (Hc), and S32F/H/R/W/Y in the light chain (Lc), which significantly improved binding to toxin B2 and formed critical protein-protein interactions. Through molecular dynamics simulations, several single mutations, such as HcS28R, LcS32H, LcS32R, LcS32W and LcS32Y, exhibited superior binding affinities to toxin B2 compared to Bez wild-type (WT), primarily attributed to Coulombic interactions. Combining the HcS28R mutation with four different mutations at residue LcS32 led to even greater binding affinities in double mutants (MTs), particularly HcS28R/LcS32H, HcS28R/LcS32R and HcS28R/LcS32Y, reinforcing protein-protein binding. Analysis of per-residue decomposition free energy highlighted key residues contributing significantly to enhanced binding interactions, emphasizing the role of electrostatic interactions. These findings offer insights into rational Bez MT design for improved toxin B2 binding, providing a foundation for developing more effective antibodies to neutralize toxin B2 and combat-related infections.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kun Karnchanapandh
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Kamonpan Sanachai
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Rungtiva P Poo-Arporn
- Biological Engineering Program, Faculty of Engineering, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Thanyada Rungrotmongkol
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok, Thailand
- Center of Excellence in Biocatalyst and Sustainable Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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2
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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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3
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Karnchanapandh K, Hanpaibool C, Sanachai K, Rungrotmongkol T. Elucidation of bezlotoxumab binding specificity to toxin B in Clostridioides difficile. J Biomol Struct Dyn 2024; 42:1617-1628. [PMID: 37098802 DOI: 10.1080/07391102.2023.2201360] [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: 12/26/2022] [Accepted: 04/05/2023] [Indexed: 04/27/2023]
Abstract
C. difficile or Clostridioides difficile infection (CDI) is currently one of the major causes of epidemics worldwide. Toxin B from Clostridioides difficile toxin B (TcdB) infection is the main target protein inhibiting CDI recurrence. Clinical research suggested that bezlotoxumab's (Bez) efficiency is significantly reduced in neutralizing the B2 strain compared to the B1 strain. The monoclonal antibody (mAb) functions by binding to the epitope 1 and 2 regions in the combined repetitive oligopeptide (CROP) domain. Some binding residues are distinctively different between B1 and B2 strains. In this work, we aimed to elucidate and compare insights into the interaction of toxins B1 and B2 in complex with Bez by using all-atom molecular dynamics (MD) simulations and binding free energy calculations. The predicted ΔGbinding values suggested that the antibody (Ab) could bind to toxin B1 significantly better than B2, supported by higher salt bridge and hydrogen bonding (H-bonding) interactions, as well as the number of contact residues between the two focused proteins. The toxin B1 residues important for binding with Bez were E1878, T1901, E1902, F1905, N1941, V1946, N2031, T2032, E2033, V2076, V2077, and E2092. The lower susceptibility of Bez towards toxin B2 was primarily due to a change of residue E2033 from glutamate to alanine (A2033) and the loss of E1878 and E1902 contributions, as determined by the intermolecular interaction changes from the dynamic residue interaction network (dRIN) analysis. The obtained data strengthen our understanding of Bez/toxin B binding.
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Affiliation(s)
- Kun Karnchanapandh
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Chonnikan Hanpaibool
- Center of Excellence in Biocatalyst and Sustainable Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Kamonpan Sanachai
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Thanyada Rungrotmongkol
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok, Thailand
- Center of Excellence in Biocatalyst and Sustainable Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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4
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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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Bratkovič T, Zahirović A, Bizjak M, Rupnik M, Štrukelj B, Berlec A. New treatment approaches for Clostridioides difficile infections: alternatives to antibiotics and fecal microbiota transplantation. Gut Microbes 2024; 16:2337312. [PMID: 38591915 PMCID: PMC11005816 DOI: 10.1080/19490976.2024.2337312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 03/27/2024] [Indexed: 04/10/2024] Open
Abstract
Clostridioides difficile causes a range of debilitating intestinal symptoms that may be fatal. It is particularly problematic as a hospital-acquired infection, causing significant costs to the health care system. Antibiotics, such as vancomycin and fidaxomicin, are still the drugs of choice for C. difficile infections, but their effectiveness is limited, and microbial interventions are emerging as a new treatment option. This paper focuses on alternative treatment approaches, which are currently in various stages of development and can be divided into four therapeutic strategies. Direct killing of C. difficile (i) includes beside established antibiotics, less studied bacteriophages, and their derivatives, such as endolysins and tailocins. Restoration of microbiota composition and function (ii) is achieved with fecal microbiota transplantation, which has recently been approved, with standardized defined microbial mixtures, and with probiotics, which have been administered with moderate success. Prevention of deleterious effects of antibiotics on microbiota is achieved with agents for the neutralization of antibiotics that act in the gut and are nearing regulatory approval. Neutralization of C. difficile toxins (iii) which are crucial virulence factors is achieved with antibodies/antibody fragments or alternative binding proteins. Of these, the monoclonal antibody bezlotoxumab is already in clinical use. Immunomodulation (iv) can help eliminate or prevent C. difficile infection by interfering with cytokine signaling. Small-molecule agents without bacteriolytic activity are usually selected by drug repurposing and can act via a variety of mechanisms. The multiple treatment options described in this article provide optimism for the future treatment of C. difficile infection.
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Affiliation(s)
- Tomaž Bratkovič
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Abida Zahirović
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Maruša Bizjak
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Maja Rupnik
- National Laboratory for Health, Environment and Food, Prvomajska 1, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Borut Štrukelj
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Aleš Berlec
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
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6
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Buddle JE, Fagan RP. Pathogenicity and virulence of Clostridioides difficile. Virulence 2023; 14:2150452. [PMID: 36419222 DOI: 10.1080/21505594.2022.2150452] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 11/02/2022] [Accepted: 11/17/2022] [Indexed: 11/25/2022] Open
Abstract
Clostridioides difficile is the most common cause of nosocomial antibiotic-associated diarrhea, and is responsible for a spectrum of diseases characterized by high levels of recurrence, morbidity, and mortality. Treatment is complex, since antibiotics constitute both the main treatment and the major risk factor for infection. Worryingly, resistance to multiple antibiotics is becoming increasingly widespread, leading to the classification of this pathogen as an urgent threat to global health. As a consummate opportunist, C. difficile is well equipped for promoting disease, owing to its arsenal of virulence factors: transmission of this anaerobe is highly efficient due to the formation of robust endospores, and an array of adhesins promote gut colonization. C. difficile produces multiple toxins acting upon gut epithelia, resulting in manifestations typical of diarrheal disease, and severe inflammation in a subset of patients. This review focuses on such virulence factors, as well as the importance of antimicrobial resistance and genome plasticity in enabling pathogenesis and persistence of this important pathogen.
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Affiliation(s)
- Jessica E Buddle
- Molecular Microbiology, School of Biosciences, University of Sheffield, Sheffield, UK
| | - Robert P Fagan
- Molecular Microbiology, School of Biosciences, University of Sheffield, Sheffield, UK
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7
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Bharathkar SK, Miller MJ, Stadtmueller BM. Engineered Secretory Immunoglobulin A provides insights on antibody-based effector mechanisms targeting Clostridiodes difficile. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566291. [PMID: 37986930 PMCID: PMC10659285 DOI: 10.1101/2023.11.08.566291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Secretory (S) Immunoglobin (Ig) A is the predominant mucosal antibody, which mediates host interactions with commensal and pathogenic microbes, including Clostridioides difficile. SIgA adopts a polymeric IgA structure that is bound by secretory component (SC). Despite significance, how SIgA supports diverse effector mechanisms is poorly characterized and SIgA-based therapies nonexistent. We engineered chimeric (c) SIgAs, in which we replaced SC domain D2 with a single domain antibody or a monomeric fluorescent protein, allowing us to investigate and enhance SIgA effector mechanisms. cSIgAs exhibited increased neutralization potency against C. difficile toxins, promoted bacterial clumping and cell rupture, and decreased cytotoxicity. cSIgA also allowed us to visualize and/or quantify C. difficile morphological changes and clumping events. Results reveal mechanisms by which SIgA combats C. difficile infection, demonstrate that cSIgA design can modulate these mechanisms, and demonstrate cSIgA's adaptability to modifications that might target a broad range of antigens and effector mechanisms.
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Affiliation(s)
- Sonya Kumar Bharathkar
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois 61801 USA
| | - Michael J. Miller
- Carle R. Woese Institute of Genomic Biology
- Department of food science and Human Nutrition, University of Illinois Urbana-Champaign, Illinois 61801 USA
| | - Beth M. Stadtmueller
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois 61801 USA
- Department of Biomedical and Translational Sciences, Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois 61801 USA
- Carle R. Woese Institute of Genomic Biology
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Berry P, Khanna S. Recurrent Clostridioides difficile Infection: Current Clinical Management and Microbiome-Based Therapies. BioDrugs 2023; 37:757-773. [PMID: 37493938 DOI: 10.1007/s40259-023-00617-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2023] [Indexed: 07/27/2023]
Abstract
Clostridioides difficile is one of the most important causes of healthcare-associated diarrhea. The high incidence and recurrence rates of C. difficile infection, as well as its associated morbidity and mortality, are great concerns. The most common complication of C. difficile infection is recurrence, with rates of 20-30% after a primary infection and 60% after three or more episodes. Medical management of recurrent C. difficile infection involves a choice of therapy that is different from the antibiotic used in the primary episode. Patients with recurrent C. difficile infection also benefit from fecal microbiota transplantation or standardized microbiome restoration therapies (approved or experimental) to restore eubiosis. In contrast to antibiotics, microbiome restoration therapies restore a normal gut flora and eliminate C. difficile colonization and infection. Fecal microbiota transplantation in recurrent C. difficile infection has demonstrated higher success rates than vancomycin, fidaxomicin, or placebo. Fecal microbiota transplantation has traditionally been considered safe, with the most common adverse reactions being abdominal discomfort, and diarrhea, and rare serious adverse events. Significant heterogeneity and a lack of standardization regarding the process of preparation, and administration of fecal microbiota transplantation remain a major pitfall. Standardized microbiome-based therapies provide a promising alternative. In the ECOSPOR III trial of SER-109, an oral formulation of bacterial spores, a significant reduction in the recurrence rate (12%) was observed compared with placebo (40%). In the phase III PUNCH CD3 trial, RBX2660 also demonstrated high efficacy rates of 70.6% versus 57.5%. Both these agents are now US Food and Drug Administration approved for recurrent C. difficile infection. Other standardized microbiome-based therapies currently in the pipeline are VE303, RBX7455, and MET-2. Antibiotic neutralization strategies, vaccines, passive monoclonal antibodies, and drug repurposing are other therapeutic strategies being explored to treat C. difficile infection.
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Affiliation(s)
- Parul Berry
- All India Institute of Medical Sciences, New Delhi, India
| | - Sahil Khanna
- Division of Gastroenterology and Hepatology, C. difficile Clinic and Microbiome Restoration Program, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA.
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9
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Kordus SL, Kroh HK, Rodríguez RC, Shrem RA, Peritore-Galve FC, Shupe JA, Wadzinski BE, Lacy DB, Spiller BW. Nanobodies against C. difficile TcdA and TcdB reveal unexpected neutralizing epitopes and provide a toolkit for toxin quantitation in vivo. PLoS Pathog 2023; 19:e1011496. [PMID: 37871122 PMCID: PMC10621975 DOI: 10.1371/journal.ppat.1011496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 11/02/2023] [Accepted: 10/07/2023] [Indexed: 10/25/2023] Open
Abstract
Clostridioides difficile is a leading cause of antibiotic-associated diarrhea and nosocomial infection in the United States. The symptoms of C. difficile infection (CDI) are associated with the production of two homologous protein toxins, TcdA and TcdB. The toxins are considered bona fide targets for clinical diagnosis as well as the development of novel prevention and therapeutic strategies. While there are extensive studies that document these efforts, there are several gaps in knowledge that could benefit from the creation of new research tools. First, we now appreciate that while TcdA sequences are conserved, TcdB sequences can vary across the span of circulating clinical isolates. An understanding of the TcdA and TcdB epitopes that drive broadly neutralizing antibody responses could advance the effort to identify safe and effective toxin-protein chimeras and fragments for vaccine development. Further, an understanding of TcdA and TcdB concentration changes in vivo can guide research into how host and microbiome-focused interventions affect the virulence potential of C. difficile. We have developed a panel of alpaca-derived nanobodies that bind specific structural and functional domains of TcdA and TcdB. We note that many of the potent neutralizers of TcdA bind epitopes within the delivery domain, a finding that could reflect roles of the delivery domain in receptor binding and/or the conserved role of pore-formation in the delivery of the toxin enzyme domains to the cytosol. In contrast, neutralizing epitopes for TcdB were found in multiple domains. The nanobodies were also used for the creation of sandwich ELISA assays that allow for quantitation of TcdA and/or TcdB in vitro and in the cecal and fecal contents of infected mice. We anticipate these reagents and assays will allow researchers to monitor the dynamics of TcdA and TcdB production over time, and the impact of various experimental interventions on toxin production in vivo.
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Affiliation(s)
- Shannon L. Kordus
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Heather K. Kroh
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Rubén Cano Rodríguez
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Rebecca A. Shrem
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - F. Christopher Peritore-Galve
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - John A. Shupe
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Brian E. Wadzinski
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - D. Borden Lacy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
| | - Benjamin W. Spiller
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
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10
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Raeisi H, Azimirad M, Asadzadeh Aghdaei H, Zarnani AH, Abdolalizadeh J, Yadegar A, Zali MR. Development and characterization of phage display-derived anti-toxin antibodies neutralizing TcdA and TcdB of Clostridioides difficile. Microbiol Spectr 2023; 11:e0531022. [PMID: 37668373 PMCID: PMC10580902 DOI: 10.1128/spectrum.05310-22] [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: 12/27/2022] [Accepted: 06/08/2023] [Indexed: 09/06/2023] Open
Abstract
TcdA and TcdB are known as the major virulence attributes of Clostridioides difficile. Hence, neutralizing the TcdA and TcdB activities can be considered as an efficient therapeutic approach against C. difficile infection (CDI). In this work, we utilized phage display technique to select single-chain fragment variable (scFv) fragments as recombinant antibodies displayed on the surface of phages, which specifically target native TcdA, or TcdB (nTcdA and nTcdB), and their recombinant C-terminal combined repetitive oligopeptide (CROP) domains (rTcdA and rTcdB). After three rounds of biopanning, abundance of phage clones displaying high reactivity with TcdA or TcdB was quantified through enzyme-linked immunosorbent assay (ELISA). Furthermore, selected scFvs were characterized by cell viability and neutralization assays. The gene expression of immunological markers, IL-8 and TNF-α, was examined in treated Caco-2 cells by RT-qPCR. The epitopes of neutralizing scFvs were also identified by molecular docking. Totally, 18 scFv antibodies (seven for TcdA and 11 for TcdB) were identified by ELISA. Among selected scFvs, two clones for TcdA (rA-C2, A-C9) and three clones for TcdB (rB-B4, B-F5, B-F11) exhibited the highest neutralizing activity in Caco-2 and Vero cells. Moreover, the cocktail of anti-TcdA and anti-TcdB antibodies notably decreased the mRNA expression of TNF-α and IL-8 in Caco-2 cells. Molecular docking revealed that the interaction between scFv and toxin was mostly restricted to CROP domain of TcdA or TcdB. Our results collectively provided more insights for the development of neutralizing scFvs against C. difficile toxins using phage display. Further research is needed to meticulously evaluate the potential of scFvs as an alternative treatment for CDI using animal models and clinical trials.IMPORTANCETargeting the major toxins of Clostridioides difficile by neutralizing antibodies is a novel therapeutic approach for CDI. Here, we report a panel of new anti-TcdA (rA-C2, A-C9) and anti-TcdB (rB-B4, B-F5, and B-F11) recombinant antibody fragments (scFvs) isolated from Tomlinson I and J libraries using phage display technique. These scFv antibodies were capable of neutralizing their respective toxin and showed promise as potential therapeutics against TcdA and TcdB of C. difficile in different in vitro models. In addition, in silico analysis showed that at least two neutralization mechanisms, including inhibiting cell surface binding of toxins and inhibiting toxin internalization can be proposed for the isolated scFvs in this work. These findings provide more insights for the applicability of specific scFvs toward C. difficile toxins at in vitro level. However, further research is required to evaluate the potential application of these scFvs as therapeutic agents for CDI treatment in clinical setting.
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Affiliation(s)
- Hamideh Raeisi
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Masoumeh Azimirad
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamid Asadzadeh Aghdaei
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir-Hassan Zarnani
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Jalal Abdolalizadeh
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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11
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Buckley PT, Chan R, Fernandez J, Luo J, Lacey KA, DuMont AL, O'Malley A, Brezski RJ, Zheng S, Malia T, Whitaker B, Zwolak A, Payne A, Clark D, Sigg M, Lacy ER, Kornilova A, Kwok D, McCarthy S, Wu B, Morrow B, Nemeth-Seay J, Petley T, Wu S, Strohl WR, Lynch AS, Torres VJ. Multivalent human antibody-centyrin fusion protein to prevent and treat Staphylococcus aureus infections. Cell Host Microbe 2023; 31:751-765.e11. [PMID: 37098341 DOI: 10.1016/j.chom.2023.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 02/12/2023] [Accepted: 04/03/2023] [Indexed: 04/27/2023]
Abstract
Treating and preventing infections by antimicrobial-resistant bacterial pathogens is a worldwide problem. Pathogens such as Staphylococcus aureus produce an array of virulence determinants, making it difficult to identify single targets for the development of vaccines or monoclonal therapies. We described a human-derived anti-S. aureus monoclonal antibody (mAb)-centyrin fusion protein ("mAbtyrin") that simultaneously targets multiple bacterial adhesins, resists proteolysis by bacterial protease GluV8, avoids Fc engagement by S. aureus IgG-binding proteins SpA and Sbi, and neutralizes pore-forming leukocidins via fusion with anti-toxin centyrins, while maintaining Fc- and complement-mediated functions. Compared with the parental mAb, mAbtyrin protected human phagocytes and boosted phagocyte-mediated killing. The mAbtyrin also reduced pathology, reduced bacterial burden, and protected from different types of infections in preclinical animal models. Finally, mAbtyrin synergized with vancomycin, enhancing pathogen clearance in an animal model of bacteremia. Altogether, these data establish the potential of multivalent mAbs for treating and preventing S. aureus diseases.
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Affiliation(s)
- Peter T Buckley
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA.
| | - Rita Chan
- Department of Microbiology, New York University Grossman School of Medicine, Alexandria Center for Life Science, 430 East 29th Street, New York, NY 10016, USA
| | - Jeffrey Fernandez
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Jinquan Luo
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Keenan A Lacey
- Department of Microbiology, New York University Grossman School of Medicine, Alexandria Center for Life Science, 430 East 29th Street, New York, NY 10016, USA
| | - Ashley L DuMont
- Department of Microbiology, New York University Grossman School of Medicine, Alexandria Center for Life Science, 430 East 29th Street, New York, NY 10016, USA
| | - Aidan O'Malley
- Department of Microbiology, New York University Grossman School of Medicine, Alexandria Center for Life Science, 430 East 29th Street, New York, NY 10016, USA
| | - Randall J Brezski
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Songmao Zheng
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Thomas Malia
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Brian Whitaker
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Adam Zwolak
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Angela Payne
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Desmond Clark
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Martin Sigg
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Eilyn R Lacy
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Anna Kornilova
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Debra Kwok
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Steve McCarthy
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Bingyuan Wu
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Brian Morrow
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | | | - Ted Petley
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - Sam Wu
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | - William R Strohl
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, USA
| | | | - Victor J Torres
- Department of Microbiology, New York University Grossman School of Medicine, Alexandria Center for Life Science, 430 East 29th Street, New York, NY 10016, USA; Antimicrobial-Resistant Pathogens Program, New York University Langone Health, Alexandria Center for Life Science, 430 East 29th Street, New York, NY 10016, USA.
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12
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Kharga K, Kumar L, Patel SKS. Recent Advances in Monoclonal Antibody-Based Approaches in the Management of Bacterial Sepsis. Biomedicines 2023; 11:biomedicines11030765. [PMID: 36979744 PMCID: PMC10045367 DOI: 10.3390/biomedicines11030765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/21/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Sepsis is a life-threatening condition characterized by an uncontrolled inflammatory response to an infectious agent and its antigens. Immune cell activation against the antigens causes severe distress that mediates a strong inflammatory response in vital organs. Sepsis is responsible for a high rate of morbidity and mortality in immunosuppressed patients. Monoclonal antibody (mAb)-based therapeutic strategies are now being explored as a viable therapy option for severe sepsis and septic shock. Monoclonal antibodies may provide benefits through two major strategies: (a) monoclonal antibodies targeting the pathogen and its components, and (b) mAbs targeting inflammatory signaling may directly suppress the production of inflammatory mediators. The major focus of mAb therapies has been bacterial endotoxin (lipopolysaccharide), although other surface antigens are also being investigated for mAb therapy. Several promising candidates for mAbs are undergoing clinical trials at present. Despite several failures and the investigation of novel targets, mAb therapy provides a glimmer of hope for the treatment of severe bacterial sepsis and septic shock. In this review, mAb candidates, their efficacy against controlling infection, with special emphasis on potential roadblocks, and prospects are discussed.
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Affiliation(s)
- Kusum Kharga
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan 173229, Himachal Pradesh, India
| | - Lokender Kumar
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan 173229, Himachal Pradesh, India
- Cancer Biology Laboratory, Raj Khosla Centre for Cancer Research, Shoolini University, Solan 173229, Himachal Pradesh, India
- Correspondence: (L.K.); (S.K.S.P.)
| | - Sanjay Kumar Singh Patel
- Department of Chemical Engineering, Konkuk University, Seoul 05029, Republic of Korea
- Correspondence: (L.K.); (S.K.S.P.)
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13
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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: 3] [Impact Index Per Article: 3.0] [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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14
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Jiang B, Yu D, Zhang Y, Hamza T, Feng H, Hoag SW. Delivery of a therapeutic antibody to the lower gastrointestinal tract for the treatment of Clostridium difficile infection (CDI). Pharm Dev Technol 2023; 28:232-239. [PMID: 36789978 DOI: 10.1080/10837450.2023.2174553] [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: 02/16/2023]
Abstract
The colonic delivery system of toxin neutralizing antibody is a promising method for treating Clostridium difficile infection (CDI) and has some advantages over the parental administration of a neutralizing antibody. However, colonic delivery of biologics presents several challenges, including instability of biologics during encapsulation into the delivery system and harsh conditions in the upper GI tract. In this work, we described a multi-particulate delivery system encapsulating a tetra-valent antibody ABAB-IgG1 with the potential to treat CDI. This work first approved that the cecum injection of ABAB-IgG1 into the lower GI tract of mice could relieve the symptoms, enhance the clinical score, and improve the survival rate of mice during CDI. Then, the antibody was spray layered onto mannitol beads and then enteric coated with pH-sensitive polymers to achieve colon-targeting release. The in vitro release of antibody from the multi-particulate system and the pH-sensitive release of antibody was monitored. The in vivo efficacy of this system was further examined and confirmed in mice and hamsters. In summary, the findings of this study should provide practical information and potential treatment options for CDI through colonic delivery of antibody therapeutics to the lower GI tract using a multi-particulate delivery system.
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Affiliation(s)
- Bowen Jiang
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD, USA
| | - Dongyue Yu
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD, USA
| | - Yongrong Zhang
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA
| | - Therwa Hamza
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA
| | - Hanping Feng
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA.,FZata Inc, Baltimore, MD, USA
| | - Stephen W Hoag
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD, USA
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15
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Lau WYV, Taylor PK, Brinkman FS, Lee AH. Pathogen-associated gene discovery workflows for novel antivirulence therapeutic development. EBioMedicine 2023; 88:104429. [PMID: 36628845 PMCID: PMC9843249 DOI: 10.1016/j.ebiom.2022.104429] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/23/2022] [Accepted: 12/15/2022] [Indexed: 01/11/2023] Open
Abstract
Novel therapeutics to manage bacterial infections are urgently needed as the impact and prevalence of antimicrobial resistance (AMR) grows. Antivirulence therapeutics are an alternative approach to antibiotics that aim to attenuate virulence rather than target bacterial essential functions, while minimizing microbiota perturbation and the risk of AMR development. Beyond known virulence factors, pathogen-associated genes (PAGs; genes found only in pathogens to date) may play an important role in virulence or host association. Many identified PAGs encode uncharacterized hypothetical proteins and represent an untapped wealth of novel drug targets. Here, we review current advances in antivirulence drug research and development, including PAG identification, and provide a comprehensive workflow from the discovery of antivirulence drug targets to drug discovery. We highlight the importance of integrating bioinformatic/genomic-based methods for novel virulence factor discovery, coupled with experimental characterization, into existing drug screening platforms to develop novel and effective antivirulence drugs.
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16
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Grace PS, Gunn BM, Lu LL. Engineering the supernatural: monoclonal antibodies for challenging infectious diseases. Curr Opin Biotechnol 2022; 78:102818. [PMID: 36242952 PMCID: PMC9612313 DOI: 10.1016/j.copbio.2022.102818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/31/2022] [Accepted: 09/04/2022] [Indexed: 12/14/2022]
Abstract
The COVID-19 pandemic demonstrated that monoclonal antibodies can be deployed faster than antimicrobials and vaccines. However, the majority of mAbs treat cancer and autoimmune diseases, whereas a minority treat infection. This is in part because targeting a single antigen by the antibody Fab domain is insufficient to stop the dynamic microbial life cycle. Thus, finding the 'right' antigens remains the focus of intense investigations. Equally important is the antibody-Fc domain that has the capacity to induce immune responses that enhance neutralization, and limit pathology and transmission. While Fc-effector functions have been less deeply studied, conceptual and technical advances reveal previously underappreciated antibody potential to combat diseases from microbes difficult to address with current diagnostics, therapeutics, and vaccines, including S. aureus, P. aeruginosa, P. falciparum, and M. tuberculosis. What is learned about engineering antibodies for these challenging organisms will enhance our approach to new and emerging infectious diseases.
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Affiliation(s)
- Patricia S Grace
- Harvard T.H. Chan School of Public Health, Boston, MA, United States; Ragon Institute of MGH, MIT and Harvard, Boston, MA, United States
| | - Bronwyn M Gunn
- Paul G. Allen School of Global Health, Washington State University, Pullman, WA, United States
| | - Lenette L Lu
- Division of Infectious Diseases and Geographic Medicine, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, United States; Department of Immunology, UT Southwestern Medical Center, Dallas, TX, United States; Parkland Health & Hospital System, United States.
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17
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Bernard SC, Washington MK, Lacy DB. Paeniclostridium sordellii uterine infection is dependent on the estrous cycle. PLoS Pathog 2022; 18:e1010997. [PMID: 36409774 PMCID: PMC9721474 DOI: 10.1371/journal.ppat.1010997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 12/05/2022] [Accepted: 11/10/2022] [Indexed: 11/22/2022] Open
Abstract
Human infections caused by the toxin-producing, anaerobic and spore-forming bacterium Paeniclostridium sordellii are associated with a treatment-refractory toxic shock syndrome (TSS). Reproductive-age women are at increased risk for P. sordellii infection (PSI) because this organism can cause intrauterine infection following childbirth, stillbirth, or abortion. PSI-induced TSS in this setting is nearly 100% fatal, and there are no effective treatments. TcsL, or lethal toxin, is the primary virulence factor in PSI and shares 70% sequence identity with Clostridioides difficile toxin B (TcdB). We therefore reasoned that a neutralizing monoclonal antibody (mAB) against TcdB might also provide protection against TcsL and PSI. We characterized two anti-TcdB mABs: PA41, which binds and prevents translocation of the TcdB glucosyltransferase domain into the cell, and CDB1, a biosimilar of bezlotoxumab, which prevents TcdB binding to a cell surface receptor. Both mABs could neutralize the cytotoxic activity of recombinant TcsL on Vero cells. To determine the efficacy of PA41 and CDB1 in vivo, we developed a transcervical inoculation method for modeling uterine PSI in mice. In the process, we discovered that the stage of the mouse reproductive cycle was a key variable in establishing symptoms of disease. By synchronizing the mice in diestrus with progesterone prior to transcervical inoculation with TcsL or vegetative P. sordellii, we observed highly reproducible intoxication and infection dynamics. PA41 showed efficacy in protecting against toxin in our transcervical in vivo model, but CDB1 did not. Furthermore, PA41 could provide protection following P. sordellii bacterial and spore infections, suggesting a path for further optimization and clinical translation in the effort to advance treatment options for PSI infection.
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Affiliation(s)
- Sarah C. Bernard
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - M. Kay Washington
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - D. Borden Lacy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
- * E-mail:
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18
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Chen B, Perry K, Jin R. Neutralizing epitopes on Clostridioides difficile toxin A revealed by the structures of two camelid VHH antibodies. Front Immunol 2022; 13:978858. [PMID: 36466927 PMCID: PMC9709291 DOI: 10.3389/fimmu.2022.978858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 10/31/2022] [Indexed: 11/18/2022] Open
Abstract
Toxin A (TcdA) and toxin B (TcdB) are two key virulence factors secreted by Clostridioides difficile, which is listed as an urgent threat by the CDC. These two large homologous exotoxins are mainly responsible for diseases associated with C. difficile infection (CDI) with symptoms ranging from diarrhea to life threatening pseudomembranous colitis. Single-domain camelid antibodies (VHHs) AH3 and AA6 are two potent antitoxins against TcdA, which when combined with two TcdB-targeting VHHs showed effective protection against both primary and recurrent CDI in animal models. Here, we report the co-crystal structures of AH3 and AA6 when they form complexes with the glucosyltransferase domain (GTD) and a fragment of the delivery and receptor-binding domain (DRBD) of TcdA, respectively. Based on these structures, we find that AH3 binding enhances the overall stability of the GTD and interferes with its unfolding at acidic pH, and AA6 may inhibit the pH-dependent conformational changes in the DRBD that is necessary for pore formation of TcdA. These studies reveal two functionally critical epitopes on TcdA and shed new insights into neutralizing mechanisms and potential development of epitope-focused vaccines against TcdA.
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Affiliation(s)
- Baohua Chen
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, United States
| | - Kay Perry
- NE-CAT, Advanced Photon Source, Argonne National Laboratory, Argonne, IL, United States,Department of Chemistry and Chemical Biology, Cornell University, Argonne, IL, United States
| | - Rongsheng Jin
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, United States,*Correspondence: Rongsheng Jin,
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19
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Kunishima H, Ohge H, Suzuki H, Nakamura A, Matsumoto K, Mikamo H, Mori N, Morinaga Y, Yanagihara K, Yamagishi Y, Yoshizawa S. Japanese Clinical Practice Guidelines for Management of Clostridioides (Clostridium) difficile infection. J Infect Chemother 2022; 28:1045-1083. [PMID: 35618618 DOI: 10.1016/j.jiac.2021.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/16/2021] [Accepted: 12/13/2021] [Indexed: 12/19/2022]
Affiliation(s)
- Hiroyuki Kunishima
- Department of Infectious Diseases, St. Marianna University School of Medicine, Japan.
| | - Hiroki Ohge
- Department of Infectious Diseases, Hiroshima University Hospital, Japan
| | - Hiromichi Suzuki
- Division of Infectious Diseases, Department of Medicine, Tsukuba Medical Center Hospital, Japan
| | - Atsushi Nakamura
- Division of Infection Control and Prevention, Nagoya City University Hospital, Japan
| | - Kazuaki Matsumoto
- Division of Pharmacodynamics, Faculty of Pharmacy, Keio University, Japan
| | - Hiroshige Mikamo
- Clinical Infectious Diseases, Graduate School of Medicine, Aichi Medical University, Japan
| | - Nobuaki Mori
- Division of General Internal Medicine and Infectious Diseases, National Hospital Organization Tokyo Medical Center, Japan
| | - Yoshitomo Morinaga
- Department of Microbiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan
| | - Katsunori Yanagihara
- Department of Laboratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Yuka Yamagishi
- Clinical Infectious Diseases, Graduate School of Medicine, Aichi Medical University, Japan
| | - Sadako Yoshizawa
- Department of Clinical Laboratory/Department of Microbiology and Infectious Diseases, Toho University School of Medicine, Japan
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20
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Wang H, Chen D, Lu H. Anti-bacterial monoclonal antibodies: next generation therapy against superbugs. Appl Microbiol Biotechnol 2022; 106:3957-3972. [PMID: 35648146 DOI: 10.1007/s00253-022-11989-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/12/2022] [Accepted: 05/16/2022] [Indexed: 12/19/2022]
Abstract
Prior to the nineteenth century, infectious disease was one of the leading causes of death. Human life expectancy has roughly doubled over the past century as a result of the development of antibiotics and vaccines. However, the emergence of antibiotic-resistant superbugs brings new challenges. The side effects of broad-spectrum antibiotics, such as causing antimicrobial resistance and destroying the normal flora, often limit their applications. Furthermore, the development of new antibiotics has lagged far behind the emergence and spread of antibiotic resistance. On the other hand, the genome complexity of bacteria makes it difficult to create effective vaccines. Therefore, novel therapeutic agents in supplement to antibiotics and vaccines are urgently needed to improve the treatment of infections. In recent years, monoclonal antibodies (mAbs) have achieved remarkable clinical success in a variety of fields. In the treatment of infectious diseases, mAbs can play functions through multiple mechanisms, including toxins neutralization, virulence factors inhibition, complement-mediated killing activity, and opsonic phagocytosis. Toxins and bacterial surface components are good targets to generate antibodies against. The U.S. FDA has approved three monoclonal antibody drugs, and there are numerous candidates in the preclinical or clinical trial stages. This article reviews recent advances in the research and development of anti-bacterial monoclonal antibody drugs in order to provide a valuable reference for future studies in this area. KEY POINTS: • Novel drugs against antibiotic-resistant superbugs are urgently required • Monoclonal antibodies can treat bacterial infections through multiple mechanisms • There are many anti-bacterial monoclonal antibodies developed in recent years and some candidates have entered the preclinical or clinical stages of development.
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Affiliation(s)
- Hui Wang
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Daijie Chen
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Huili Lu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
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21
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Saleh A, Ansari U, Abughazaleh S, Glassner K, Abraham BP. Biological Therapies for the Management of Enteric Disease: Considerations for the Clinician. Biologics 2022; 16:67-83. [PMID: 35747234 PMCID: PMC9211072 DOI: 10.2147/btt.s335697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 05/25/2022] [Indexed: 11/23/2022]
Affiliation(s)
- Adam Saleh
- Engineering Medicine, Texas A&M University, Houston, TX, USA
- Department of Medicine – Division of Gastroenterology, Houston Methodist, Houston, TX, USA
| | - Usman Ansari
- Department of Medicine – Division of Gastroenterology, Houston Methodist, Houston, TX, USA
| | - Shaadi Abughazaleh
- Department of Medicine – Division of Gastroenterology, Houston Methodist, Houston, TX, USA
| | - Kerri Glassner
- Department of Medicine – Division of Gastroenterology, Houston Methodist, Houston, TX, USA
| | - Bincy P Abraham
- Department of Medicine – Division of Gastroenterology, Houston Methodist, Houston, TX, USA
- Correspondence: Bincy P Abraham, Department of Medicine – Division of Gastroenterology, Houston Methodist, 6550 Fannin St. Suite 1201, Houston, TX, 77030, USA, Tel +1-713-441-5042, Fax +1-713-797-0622, Email
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22
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Kordus SL, Thomas AK, Lacy DB. Clostridioides difficile toxins: mechanisms of action and antitoxin therapeutics. Nat Rev Microbiol 2022; 20:285-298. [PMID: 34837014 PMCID: PMC9018519 DOI: 10.1038/s41579-021-00660-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2021] [Indexed: 01/03/2023]
Abstract
Clostridioides difficile is a Gram-positive anaerobe that can cause a spectrum of disorders that range in severity from mild diarrhoea to fulminant colitis and/or death. The bacterium produces up to three toxins, which are considered the major virulence factors in C. difficile infection. These toxins promote inflammation, tissue damage and diarrhoea. In this Review, we highlight recent biochemical and structural advances in our understanding of the mechanisms that govern host-toxin interactions. Understanding how C. difficile toxins affect the host forms a foundation for developing novel strategies for treatment and prevention of C. difficile infection.
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Affiliation(s)
- Shannon L. Kordus
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA,Center for Structural Biology, Vanderbilt University, Nashville, TN, USA,These authors contributed equally: Shannon L. Kordus, Audrey K. Thomas
| | - Audrey K. Thomas
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA,Center for Structural Biology, Vanderbilt University, Nashville, TN, USA,These authors contributed equally: Shannon L. Kordus, Audrey K. Thomas
| | - D. Borden Lacy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA,Center for Structural Biology, Vanderbilt University, Nashville, TN, USA,The Veterans Affairs, Tennessee Valley Healthcare, System, Nashville, TN, USA,
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23
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Liu J, Kothe M, Zhang J, Oloo E, Stegalkina S, Mundle ST, Li L, Zhang J, Cole LE, Barone L, Biemann HP, Kleanthous H, Anosova NG, Anderson SF. Novel structural insights for a pair of monoclonal antibodies recognizing non-overlapping epitopes of the glucosyltransferase domain of Clostridium difficile toxin B. Curr Res Struct Biol 2022; 4:96-105. [PMID: 35469152 PMCID: PMC9034018 DOI: 10.1016/j.crstbi.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/11/2022] [Accepted: 03/24/2022] [Indexed: 11/06/2022] Open
Abstract
Clostridium difficile toxins are the primary causative agents for hospital-acquired diarrhea and pseudomembranous colitis. Numerous monoclonal antibodies (mAbs) targeting different domains of Clostridium difficile toxin have been reported. Here we report the crystal structures of two mAbs, B1 and B2, in complex with the glycosyltransferase domain (GTD) of the Clostridium difficile toxin B (TcdB). B2 bound to the N-terminal 4 helix bundle of the GTD, a conserved membrane localization domain (MLD) found in the large clostridial glycosylating toxin family implicated in targeting plasma membrane. B1 bound to a distinct epitope at the hinge region between the MLD and the catalytic subdomain of the GTD. Functional studies revealed the potency of these mAbs in vitro and in vivo to be synergistic when given in combination. Identified 2 novel potent mAbs B1 and B2 targeting the TcdB GTD domain and synergistic effects were observed when combined. Novel non-overlapped epitopes were identified for B1 and B2 through X-ray crystallography. B2 epitope belongs to a conserved MLD (membrane localization domain) in the large clostridial glycosylating toxin family. B2 was shown to target the key regions (Loop 1 and Loop 3) of MLD proposed to be essential for membrane localization. B1 epitope was found to be at the hinge region between the GTD catalytic domain and the MLD of GTD.
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24
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Chen B, Basak S, Chen P, Zhang C, Perry K, Tian S, Yu C, Dong M, Huang L, Bowen ME, Jin R. Structure and conformational dynamics of Clostridioides difficile toxin A. Life Sci Alliance 2022; 5:5/6/e202201383. [PMID: 35292538 PMCID: PMC8924006 DOI: 10.26508/lsa.202201383] [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] [Received: 01/21/2022] [Revised: 02/25/2022] [Accepted: 02/28/2022] [Indexed: 01/05/2023] Open
Abstract
This study presents a complete structural model of TcdA holotoxin and sheds new lights into the conformational dynamics of TcdA and its roles in TcdA intoxication. Clostridioides difficile toxin A and B (TcdA and TcdB) are two major virulence factors responsible for diseases associated with C. difficile infection (CDI). Here, we report the 3.18-Å resolution crystal structure of a TcdA fragment (residues L843–T2481), which advances our understanding of the complete structure of TcdA holotoxin. Our structural analysis, together with complementary single molecule FRET and limited proteolysis studies, reveal that TcdA adopts a dynamic structure and its CROPs domain can sample a spectrum of open and closed conformations in a pH-dependent manner. Furthermore, a small globular subdomain (SGS) and the CROPs protect the pore-forming region of TcdA in the closed state at neutral pH, which could contribute to modulating the pH-dependent pore formation of TcdA. A rationally designed TcdA mutation that trapped the CROPs in the closed conformation showed drastically reduced cytotoxicity. Taken together, these studies shed new lights into the conformational dynamics of TcdA and its roles in TcdA intoxication.
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Affiliation(s)
- Baohua Chen
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Sujit Basak
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Peng Chen
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Changcheng Zhang
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Kay Perry
- NE-CAT and Department of Chemistry and Chemical Biology, Cornell University, Argonne National Laboratory, Argonne, IL, USA
| | - Songhai Tian
- Department of Urology, Boston Children's Hospital, Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Clinton Yu
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Min Dong
- Department of Urology, Boston Children's Hospital, Department of Microbiology and Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Lan Huang
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Mark E Bowen
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Rongsheng Jin
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA, USA
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25
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Abstract
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The paradigm of antivirulence
therapy dictates that bacterial pathogens
are specifically disarmed but not killed by neutralizing their virulence
factors. Clearance of the invading pathogen by the immune system is
promoted. As compared to antibiotics, the pathogen-selective antivirulence
drugs hold promise to minimize collateral damage to the beneficial
microbiome. Also, selective pressure for resistance is expected to
be lower because bacterial viability is not directly affected. Antivirulence
drugs are being developed for stand-alone prophylactic and therapeutic
treatments but also for combinatorial use with antibiotics. This Review
focuses on drug modalities that target bacterial exotoxins after the
secretion or release-upon-lysis. Exotoxins have a significant and
sometimes the primary role as the disease-causing virulence factor,
and thereby they are attractive targets for drug development. We describe
the key pre-clinical and clinical trial data that have led to the
approval of currently used exotoxin-targeted drugs, namely the monoclonal
antibodies bezlotoxumab (toxin B/TcdB, Clostridioides difficile), raxibacumab (anthrax toxin, Bacillus anthracis), and obiltoxaximab (anthrax toxin, Bacillus anthracis), but also to challenges with some of the promising leads. We also
highlight the recent developments in pre-clinical research sector
to develop exotoxin-targeted drug modalities, i.e., monoclonal antibodies,
antibody fragments, antibody mimetics, receptor analogs, neutralizing
scaffolds, dominant-negative mutants, and small molecules. We describe
how these exotoxin-targeted drug modalities work with high-resolution
structural knowledge and highlight their advantages and disadvantages
as antibiotic alternatives.
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Affiliation(s)
- Moona Sakari
- Institute of Biomedicine, Research Unit for Infection and Immunity, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
| | - Arttu Laisi
- Institute of Biomedicine, Research Unit for Infection and Immunity, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
| | - Arto T. Pulliainen
- Institute of Biomedicine, Research Unit for Infection and Immunity, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
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26
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Phanchana M, Harnvoravongchai P, Wongkuna S, Phetruen T, Phothichaisri W, Panturat S, Pipatthana M, Charoensutthivarakul S, Chankhamhaengdecha S, Janvilisri T. Frontiers in antibiotic alternatives for Clostridioides difficile infection. World J Gastroenterol 2021; 27:7210-7232. [PMID: 34876784 PMCID: PMC8611198 DOI: 10.3748/wjg.v27.i42.7210] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/12/2021] [Accepted: 10/25/2021] [Indexed: 02/06/2023] Open
Abstract
Clostridioides difficile (C. difficile) is a gram-positive, anaerobic spore-forming bacterium and a major cause of antibiotic-associated diarrhea. Humans are naturally resistant to C. difficile infection (CDI) owing to the protection provided by healthy gut microbiota. When the gut microbiota is disturbed, C. difficile can colonize, produce toxins, and manifest clinical symptoms, ranging from asymptomatic diarrhea and colitis to death. Despite the steady-if not rising-prevalence of CDI, it will certainly become more problematic in a world of antibiotic overuse and the post-antibiotic era. C. difficile is naturally resistant to most of the currently used antibiotics as it uses multiple resistance mechanisms. Therefore, current CDI treatment regimens are extremely limited to only a few antibiotics, which include vancomycin, fidaxomicin, and metronidazole. Therefore, one of the main challenges experienced by the scientific community is the development of alternative approaches to control and treat CDI. In this Frontier article, we collectively summarize recent advances in alternative treatment approaches for CDI. Over the past few years, several studies have reported on natural product-derived compounds, drug repurposing, high-throughput library screening, phage therapy, and fecal microbiota transplantation. We also include an update on vaccine development, pre- and pro-biotics for CDI, and toxin antidote approaches. These measures tackle CDI at every stage of disease pathology via multiple mechanisms. We also discuss the gaps and concerns in these developments. The next epidemic of CDI is not a matter of if but a matter of when. Therefore, being well-equipped with a collection of alternative therapeutics is necessary and should be prioritized.
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Affiliation(s)
- Matthew Phanchana
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | | | - Supapit Wongkuna
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Tanaporn Phetruen
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Wichuda Phothichaisri
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Supakan Panturat
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Methinee Pipatthana
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Sitthivut Charoensutthivarakul
- School of Bioinnovation and Bio-based Product Intelligence, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | | | - Tavan Janvilisri
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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27
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Liu Z, Zhang S, Chen P, Tian S, Zeng J, Perry K, Dong M, Jin R. Structural basis for selective modification of Rho and Ras GTPases by Clostridioides difficile toxin B. SCIENCE ADVANCES 2021; 7:eabi4582. [PMID: 34678063 PMCID: PMC8535798 DOI: 10.1126/sciadv.abi4582] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/02/2021] [Indexed: 05/15/2023]
Abstract
Toxin B (TcdB) is a primary cause of Clostridioides difficile infection (CDI). This toxin acts by glucosylating small GTPases in the Rho/Ras families, but the structural basis for TcdB recognition and selectivity of specific GTPase substrates remain unsolved. Here, we report the cocrystal structures of the glucosyltransferase domain (GTD) of two distinct TcdB variants in complex with human Cdc42 and R-Ras, respectively. These structures reveal a common structural mechanism by which TcdB recognizes Rho and R-Ras. Furthermore, we find selective clustering of adaptive residue changes in GTDs that determine their substrate preferences, which helps partition all known TcdB variants into two groups that display distinct specificities toward Rho or R-Ras. Mutations that selectively disrupt GTPases binding reduce the glucosyltransferase activity of the GTD and the toxicity of TcdB holotoxin. These findings establish the structural basis for TcdB recognition of small GTPases and reveal strategies for therapeutic interventions for CDI.
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Affiliation(s)
- Zheng Liu
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Sicai Zhang
- Department of Urology, Boston Children’s Hospital, and Departments of Microbiology and Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Peng Chen
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Songhai Tian
- Department of Urology, Boston Children’s Hospital, and Departments of Microbiology and Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Ji Zeng
- Department of Urology, Boston Children’s Hospital, and Departments of Microbiology and Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Kay Perry
- NE-CAT and Department of Chemistry and Chemical Biology, Cornell University, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Min Dong
- Department of Urology, Boston Children’s Hospital, and Departments of Microbiology and Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Rongsheng Jin
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
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28
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Yakovlieva L, Fülleborn JA, Walvoort MTC. Opportunities and Challenges of Bacterial Glycosylation for the Development of Novel Antibacterial Strategies. Front Microbiol 2021; 12:745702. [PMID: 34630370 PMCID: PMC8498110 DOI: 10.3389/fmicb.2021.745702] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 08/27/2021] [Indexed: 12/29/2022] Open
Abstract
Glycosylation is a ubiquitous process that is universally conserved in nature. The various products of glycosylation, such as polysaccharides, glycoproteins, and glycolipids, perform a myriad of intra- and extracellular functions. The multitude of roles performed by these molecules is reflected in the significant diversity of glycan structures and linkages found in eukaryotes and prokaryotes. Importantly, glycosylation is highly relevant for the virulence of many bacterial pathogens. Various surface-associated glycoconjugates have been identified in bacteria that promote infectious behavior and survival in the host through motility, adhesion, molecular mimicry, and immune system manipulation. Interestingly, bacterial glycosylation systems that produce these virulence factors frequently feature rare monosaccharides and unusual glycosylation mechanisms. Owing to their marked difference from human glycosylation, bacterial glycosylation systems constitute promising antibacterial targets. With the rise of antibiotic resistance and depletion of the antibiotic pipeline, novel drug targets are urgently needed. Bacteria-specific glycosylation systems are especially promising for antivirulence therapies that do not eliminate a bacterial population, but rather alleviate its pathogenesis. In this review, we describe a selection of unique glycosylation systems in bacterial pathogens and their role in bacterial homeostasis and infection, with a focus on virulence factors. In addition, recent advances to inhibit the enzymes involved in these glycosylation systems and target the bacterial glycan structures directly will be highlighted. Together, this review provides an overview of the current status and promise for the future of using bacterial glycosylation to develop novel antibacterial strategies.
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Affiliation(s)
- Liubov Yakovlieva
- Faculty of Science and Engineering, Stratingh Institute for Chemistry, University of Groningen, Groningen, Netherlands
| | - Julius A Fülleborn
- Faculty of Science and Engineering, Stratingh Institute for Chemistry, University of Groningen, Groningen, Netherlands
| | - Marthe T C Walvoort
- Faculty of Science and Engineering, Stratingh Institute for Chemistry, University of Groningen, Groningen, Netherlands
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29
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Xu X, Bian Q, Luo Y, Song X, Lin S, Chen H, Liang Q, Wang M, Ye G, Zhu B, Chen L, Tang YW, Wang X, Jin D. Comparative Whole Genome Sequence Analysis and Biological Features of Clostridioides difficile Sequence Type 2 ‡. Front Microbiol 2021; 12:651520. [PMID: 34290677 PMCID: PMC8287029 DOI: 10.3389/fmicb.2021.651520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 05/31/2021] [Indexed: 01/05/2023] Open
Abstract
Clostridioides difficile sequence type 2 (ST2) has been increasingly recognized as one of the major genotypes in China, while the genomic characteristics and biological phenotypes of Chinese ST2 strains remain to be determined. We used whole-genome sequencing and phylogenetic analysis to investigate the genomic features of 182 ST2 strains, isolated between 2011 and 2017. PCR ribotyping (RT) was performed, and antibiotic resistance, toxin concentration, and sporulation capacity were measured. The core genome Maximum-likelihood phylogenetic analysis showed that ST2 strains were distinctly segregated into two genetically diverse lineages [L1 (67.0% from Northern America) and L2], while L2 further divided into two sub-lineages, SL2a and SL2b (73.5% from China). The 36 virulence-related genes were widely distributed in ST2 genomes, but in which only 11 antibiotic resistance-associated genes were dispersedly found. Among the 25 SL2b sequenced isolates, RT014 (40.0%, n = 10) and RT020 (28.0%, n = 7) were two main genotypes with no significant difference on antibiotic resistance (χ2 = 0.024-2.667, P > 0.05). A non-synonymous amino acid substitution was found in tcdB (Y1975D) which was specific to SL2b. Although there was no significant difference in sporulation capacity between the two lineages, the average toxin B concentration (5.11 ± 3.20 ng/μL) in SL2b was significantly lower in comparison to those in L1 (10.49 ± 15.82 ng/μL) and SL2a (13.92 ± 2.39 ng/μL) (χ2 = 12.30, P < 0.05). This study described the genomic characteristics of C. difficile ST2, with many virulence loci and few antibiotic resistance elements. The Chinese ST2 strains with the mutation in codon 1975 of the tcdB gene clustering in SL2b circulating in China express low toxin B, which may be associated with mild or moderate C. difficile infection.
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Affiliation(s)
- Xingxing Xu
- Department of Clinical Laboratory, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China.,School of Laboratory Medicine, Hangzhou Medical College, Hangzhou, China
| | - Qiao Bian
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Yun Luo
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Xiaojun Song
- Centre of Laboratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Shan Lin
- School of Laboratory Medicine, Hangzhou Medical College, Hangzhou, China
| | - Huan Chen
- Key Laboratory of Microorganism Technology and Bioinformatics Research of Zhejiang Province, Hangzhou, China.,NMPA Key Laboratory for Testing and Risk Warning of Pharmaceutical Microbiology, Hangzhou, China
| | - Qian Liang
- Key Laboratory of Microorganism Technology and Bioinformatics Research of Zhejiang Province, Hangzhou, China.,NMPA Key Laboratory for Testing and Risk Warning of Pharmaceutical Microbiology, Hangzhou, China
| | - Meixia Wang
- Key Laboratory of Microorganism Technology and Bioinformatics Research of Zhejiang Province, Hangzhou, China.,NMPA Key Laboratory for Testing and Risk Warning of Pharmaceutical Microbiology, Hangzhou, China
| | - Guangyong Ye
- Department of Clinical Laboratory, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bo Zhu
- Department of Clinical Laboratory, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Liang Chen
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, Untied States.,Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, NJ, Untied States
| | - Yi-Wei Tang
- Cepheid, Danaher Diagnostic Platform, Shanghai, China
| | - Xianjun Wang
- Department of Clinical Laboratory, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Dazhi Jin
- School of Laboratory Medicine, Hangzhou Medical College, Hangzhou, China.,Centre of Laboratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
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30
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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: 28] [Impact Index Per Article: 9.3] [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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31
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Abstract
Large clostridial toxins (LCTs) are a family of bacterial exotoxins that infiltrate and destroy target cells. Members of the LCT family include Clostridioides difficile toxins TcdA and TcdB, Paeniclostridium sordellii toxins TcsL and TcsH, Clostridium novyi toxin TcnA, and Clostridium perfringens toxin TpeL. Since the 19th century, LCT-secreting bacteria have been isolated from the blood, organs, and wounds of diseased individuals, and LCTs have been implicated as the primary virulence factors in a variety of infections, including C. difficile infection and some cases of wound-associated gas gangrene. Clostridia express and secrete LCTs in response to various physiological signals. LCTs invade host cells by binding specific cell surface receptors, ultimately leading to internalization into acidified vesicles. Acidic pH promotes conformational changes within LCTs, which culminates in translocation of the N-terminal glycosyltransferase and cysteine protease domain across the endosomal membrane and into the cytosol, leading first to cytopathic effects and later to cytotoxic effects. The focus of this review is on the role of LCTs in infection and disease, the mechanism of LCT intoxication, with emphasis on recent structural work and toxin subtyping analysis, and the genomic discovery and characterization of LCT homologues. We provide a comprehensive review of these topics and offer our perspective on emerging questions and future research directions for this enigmatic family of toxins.
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32
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Kelly CP, Poxton IR, Shen J, Wilcox MH, Gerding DN, Zhao X, Laterza OF, Railkar R, Guris D, Dorr MB. Effect of Endogenous Clostridioides difficile Toxin Antibodies on Recurrence of C. difficile Infection. Clin Infect Dis 2021; 71:81-86. [PMID: 31628838 DOI: 10.1093/cid/ciz809] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 09/30/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Endogenous antibodies (eAbs) against Clostridioides (Clostridium) difficile toxins may protect against recurrence of C. difficile infection (rCDI). This hypothesis was tested using placebo group data from MODIFY (Monoclonal Antibodies for C. difficile Therapy) I and II (NCT01241552 and NCT01513239, respectively), global, randomized phase 3 trials that assessed the efficacy and safety of the antitoxin monoclonal antibodies bezlotoxumab and actoxumab in participants receiving antibiotic therapy for CDI. METHODS A placebo infusion (normal saline) was administered on study day 1. Serum samples were collected on day 1, week 4, and week 12, and eAb-A and eAb-B titers were measured by 2 validated electrochemiluminescence immunoassays. Rates of initial clinical cure and rCDI were summarized by eAb titer category (low, medium, high) at each time point. RESULTS Serum eAb titers were available from a total of 773 participants. The proportion of participants with high eAb-A and eAb-B titers increased over time. Rates of initial clinical cure were similar across eAb titer categories. There was no correlation between eAb-A titers and rCDI rate at any time point. However, there was a negative correlation between rCDI and eAb-B titer on day 1 and week 4. rCDI occurred in 22% of participants with high eAb-B titers at baseline compared with 35% with low or medium titers (P = .015). CONCLUSIONS Higher eAb titers against toxin B, but not toxin A, were associated with protection against rCDI. These data are consistent with the observed efficacy of bezlotoxumab, and lack of efficacy of actoxumab, in the MODIFY trials. CLINICAL TRIALS REGISTRATION NCT01241552 and NCT01513239.
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Affiliation(s)
- Ciarán P Kelly
- Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Ian R Poxton
- University of Edinburgh, Edinburgh, United Kingdom
| | | | - Mark H Wilcox
- Leeds Teaching Hospitals and University of Leeds, United Kingdom
| | - Dale N Gerding
- Loyola University Chicago Stritch School of Medicine, Maywood.,Edward Hines Jr Veterans Affairs Hospital, Hines, Illinois
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33
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Phylogenomics of 8,839 Clostridioides difficile genomes reveals recombination-driven evolution and diversification of toxin A and B. PLoS Pathog 2020; 16:e1009181. [PMID: 33370413 PMCID: PMC7853461 DOI: 10.1371/journal.ppat.1009181] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 02/02/2021] [Accepted: 11/23/2020] [Indexed: 12/15/2022] Open
Abstract
Clostridioides difficile is the major worldwide cause of antibiotic-associated gastrointestinal infection. A pathogenicity locus (PaLoc) encoding one or two homologous toxins, toxin A (TcdA) and toxin B (TcdB), is essential for C. difficile pathogenicity. However, toxin sequence variation poses major challenges for the development of diagnostic assays, therapeutics, and vaccines. Here, we present a comprehensive phylogenomic analysis of 8,839 C. difficile strains and their toxins including 6,492 genomes that we assembled from the NCBI short read archive. A total of 5,175 tcdA and 8,022 tcdB genes clustered into 7 (A1-A7) and 12 (B1-B12) distinct subtypes, which form the basis of a new method for toxin-based subtyping of C. difficile. We developed a haplotype coloring algorithm to visualize amino acid variation across all toxin sequences, which revealed that TcdB has diversified through extensive homologous recombination throughout its entire sequence, and formed new subtypes through distinct recombination events. In contrast, TcdA varies mainly in the number of repeats in its C-terminal repetitive region, suggesting that recombination-mediated diversification of TcdB provides a selective advantage in C. difficile evolution. The application of toxin subtyping is then validated by classifying 351 C. difficile clinical isolates from Brigham and Women's Hospital in Boston, demonstrating its clinical utility. Subtyping partitions TcdB into binary functional and antigenic groups generated by intragenic recombinations, including two distinct cell-rounding phenotypes, whether recognizing frizzled proteins as receptors, and whether it can be efficiently neutralized by monoclonal antibody bezlotoxumab, the only FDA-approved therapeutic antibody. Our analysis also identifies eight universally conserved surface patches across the TcdB structure, representing ideal targets for developing broad-spectrum therapeutics. Finally, we established an open online database (DiffBase) as a central hub for collection and classification of C. difficile toxins, which will help clinicians decide on therapeutic strategies targeting specific toxin variants, and allow researchers to monitor the ongoing evolution and diversification of C. difficile.
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Generation and Characterization of Typhoid Toxin-Neutralizing Human Monoclonal Antibodies. Infect Immun 2020; 88:IAI.00292-20. [PMID: 32661121 DOI: 10.1128/iai.00292-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/06/2020] [Indexed: 11/20/2022] Open
Abstract
Typhoid toxin is a virulence factor of Salmonella enterica serovar Typhi, the causative agent of typhoid fever, and is thought to be responsible for the symptoms of severe disease. This toxin has a unique A2B5 architecture with two active subunits, the ADP ribosyl transferase PltA and the DNase CdtB, linked to a pentameric B subunit, which is alternatively made of PltB or PltC. Here, we describe the generation and characterization of typhoid toxin-neutralizing human monoclonal antibodies by immunizing genetically engineered mice that have a full set of human immunoglobulin variable region genes. We identified several monoclonal antibodies with strong in vitro and in vivo toxin-neutralizing activity and different mechanisms of toxin neutralization. These antibodies could serve as the basis for the development of novel therapeutic strategies against typhoid fever.
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Shah HB, Smith K, Scott EJ, Larabee JL, James JA, Ballard JD, Lang ML. Human C. difficile toxin-specific memory B cell repertoires encode poorly neutralizing antibodies. JCI Insight 2020; 5:138137. [PMID: 32663199 PMCID: PMC7455132 DOI: 10.1172/jci.insight.138137] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/08/2020] [Indexed: 12/18/2022] Open
Abstract
Clostridioides difficile is a leading cause of nosocomial infection responsible for significant morbidity and mortality with limited options for therapy. Secreted C. difficile toxin B (TcdB) is a major contributor to disease pathology, and select TcdB-specific Abs may protect against disease recurrence. However, the high frequency of recurrence suggests that the memory B cell response, essential for new Ab production following C. difficile reexposure, is insufficient. We therefore isolated TcdB-specific memory B cells from individuals with a history of C. difficile infection and performed single-cell deep sequencing of their Ab genes. Herein, we report that TcdB-specific memory B cell–encoded antibodies showed somatic hypermutation but displayed limited isotype class switch. Memory B cell–encoded mAb generated from the gene sequences revealed low to moderate affinity for TcdB and a limited ability to neutralize TcdB. These findings indicate that memory B cells are an important factor in C. difficile disease recurrence. The C. difficile toxin-specific human memory B cell repertoire encodes low-affinity, non-neutralizing antibodies.
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Affiliation(s)
- Hemangi B Shah
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center (OUHSC)
| | - Kenneth Smith
- Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, and
| | - Edgar J Scott
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center (OUHSC)
| | - Jason L Larabee
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center (OUHSC)
| | - Judith A James
- Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, and.,Departments of Medicine and Pathology, OUHSC, University of Oklahoma, Oklahoma City, Oklahoma, USA
| | - Jimmy D Ballard
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center (OUHSC)
| | - Mark L Lang
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center (OUHSC)
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Giacobbe DR, Dettori S, Di Bella S, Vena A, Granata G, Luzzati R, Petrosillo N, Bassetti M. Bezlotoxumab for Preventing Recurrent Clostridioides difficile Infection: A Narrative Review from Pathophysiology to Clinical Studies. Infect Dis Ther 2020; 9:481-494. [PMID: 32632582 PMCID: PMC7452994 DOI: 10.1007/s40121-020-00314-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Indexed: 12/17/2022] Open
Abstract
Clostridioides difficile infection (CDI) and recurrent CDI (rCDI) remain associated with a reduction in the patients’ quality of life and with increased healthcare costs. Bezlotoxumab is a monoclonal antibody against toxin B of C. difficile, approved for prevention of rCDI. In this narrative review, we briefly discuss the pathophysiology of CDI and the mechanism of action of bezlotoxumab, as well as the available evidence from investigational and observational studies in terms of efficacy, effectiveness, and safety of bezlotoxumab for the prevention of rCDI. Overall, bezlotoxumab has proved efficacious in reducing the burden of rCDI, thereby providing clinicians with an important novel strategy to achieve sustained cure. Nonetheless, experiences outside randomized controlled trials (RCTs) remain scant, and mostly represented by case series without a control group. Along with the conduction of RCTs to directly compare bezlotoxumab with faecal microbiota transplantation (or to precisely evaluate the role of their combined use), further widening our post-marketing experience remains paramount to firmly guide the use of bezlotoxumab outside RCTs, and to clearly identify those real-life settings where its preventive benefits can be exploited most.
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Affiliation(s)
- Daniele Roberto Giacobbe
- Infectious Diseases Unit, Ospedale Policlinico San Martino, IRCCS, Genoa, Italy.
- Department of Health Sciences, University of Genoa, Genoa, Italy.
| | - Silvia Dettori
- Infectious Diseases Unit, Ospedale Policlinico San Martino, IRCCS, Genoa, Italy
- Department of Health Sciences, University of Genoa, Genoa, Italy
| | - Stefano Di Bella
- Clinical Department of Medical, Surgical and Health Sciences, Trieste University, Trieste, Italy
| | - Antonio Vena
- Infectious Diseases Unit, Ospedale Policlinico San Martino, IRCCS, Genoa, Italy
| | - Guido Granata
- Clinical and Research Department for Infectious Diseases, Severe and Immunedepression-Associated Infections Unit, National Institute for Infectious Diseases L. Spallanzani, IRCCS, Rome, Italy
| | - Roberto Luzzati
- Clinical Department of Medical, Surgical and Health Sciences, Trieste University, Trieste, Italy
| | - Nicola Petrosillo
- Clinical and Research Department for Infectious Diseases, Severe and Immunedepression-Associated Infections Unit, National Institute for Infectious Diseases L. Spallanzani, IRCCS, Rome, Italy
| | - Matteo Bassetti
- Infectious Diseases Unit, Ospedale Policlinico San Martino, IRCCS, Genoa, Italy
- Department of Health Sciences, University of Genoa, Genoa, Italy
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Li Z, Lee K, Rajyaguru U, Jones CH, Janezic S, Rupnik M, Anderson AS, Liberator P. Ribotype Classification of Clostridioides difficile Isolates Is Not Predictive of the Amino Acid Sequence Diversity of the Toxin Virulence Factors TcdA and TcdB. Front Microbiol 2020; 11:1310. [PMID: 32636819 PMCID: PMC7318873 DOI: 10.3389/fmicb.2020.01310] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 05/25/2020] [Indexed: 12/18/2022] Open
Abstract
Clostridioides (Clostridium) difficile is the most commonly recognized cause of infectious diarrhea in healthcare settings. Currently there is no vaccine to prevent initial or recurrent C. difficile infection (CDI). Two large clostridial toxins, TcdA and TcdB, are the primary virulence factors for CDI. Immunological approaches to prevent CDI include antibody-mediated neutralization of the cytotoxicity of these toxins. An understanding of the sequence diversity of the two toxins expressed by disease causing isolates is critical for the interpretation of the immune response to the toxins. In this study, we determined the whole genome sequence (WGS) of 478 C. difficile isolates collected in 12 countries between 2004 and 2018 to probe toxin variant diversity. A total of 44 unique TcdA variants and 37 unique TcdB variants were identified. The amino acid sequence conservation among the TcdA variants (≥98%) is considerably greater than among the TcdB variants (as low as 86.1%), suggesting that different selection pressures may have contributed to the evolution of the two toxins. Phylogenomic analysis of the WGS data demonstrate that isolates grouped together based on ribotype or MLST code for multiple different toxin variants. These findings illustrate the importance of determining not only the ribotype but also the toxin sequence when evaluating strain coverage using vaccine strategies that target these virulence factors. We recommend that toxin variant type and sequence type (ST), be used together with ribotype data to provide a more comprehensive strain classification scheme for C. difficile surveillance during vaccine development objectives.
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Affiliation(s)
- Zhenghui Li
- Vaccine Research and Development, Pfizer Inc., Pearl River, NY, United States
| | - Kwok Lee
- Vaccine Research and Development, Pfizer Inc., Pearl River, NY, United States
| | - Urvi Rajyaguru
- Vaccine Research and Development, Pfizer Inc., Pearl River, NY, United States
| | - C Hal Jones
- Vaccine Research and Development, Pfizer Inc., Pearl River, NY, United States
| | - Sandra Janezic
- National Laboratory for Health, Environment and Food, Maribor, Slovenia.,Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Maja Rupnik
- National Laboratory for Health, Environment and Food, Maribor, Slovenia.,Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | | | - Paul Liberator
- Vaccine Research and Development, Pfizer Inc., Pearl River, NY, United States
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38
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Jiang H, Xu W, Liu R, Gupta B, Kilgore B, Du Z, Yang X. Characterization of Bispecific Antibody Production in Cell Cultures by Unique Mixed Mode Size Exclusion Chromatography. Anal Chem 2020; 92:9312-9321. [DOI: 10.1021/acs.analchem.0c01641] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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39
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Gao Y, Li H, Yang H, Su J, Huang L. The current novel therapeutic regimens for Clostridium difficile infection (CDI) and the potentials of Traditional Chinese Medicine in treatment of CDI. Crit Rev Microbiol 2019; 45:729-742. [PMID: 31838936 DOI: 10.1080/1040841x.2019.1700905] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Clostridium difficile infection (CDI) is featured as the dysbiosis of gut microbiota and consequent mild diarrhoea or severe pseudomembranous colitis. However, the frequent recurrence of CDI following treatment course challenged the antibiotic therapy. Currently, to address the relapse of CDI, several novel therapeutic approaches have emerged, including Bezlotoxumab, SYN-004 (Ribaxamase), RBX2660, and faecal microbial transplant. Traditional Chinese Medicine (TCM) is an old medical system accumulated for thousands of years. Orientated by syndrome-based treatment, TCM functions in a multicomponent and multitarget mode. This old medical system showed superiority over conventional medical treatment, particularly in the treatment of complex disorders, including CDI. In the present review, we will elaborate the TCM intervention in the management of CDI and others disorders via restoring the gut microbiota dysbiosis. We hope that this review will deepen our understanding of TCM as an alternative to CDI treatment. However, more rigorously designed basic researches and randomised controlled trials need to conduct to appraise the function mechanisms and effects of TCM. Finally, it is concluded that the combined therapeutic potentials of TCM and western medicine could be harness to resolve the recurrence and improve the outcome of CDI.
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Affiliation(s)
- Yan Gao
- Department of Clinical Laboratory Diagnostics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Hui Li
- Institute of Chinese Materia Medica, Chinese Academy of Chinese Medical Sciences, Beijing, China
| | - Hongjun Yang
- Institute of Chinese Materia Medica, Chinese Academy of Chinese Medical Sciences, Beijing, China
| | - Jianrong Su
- Department of Clinical Laboratory Diagnostics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Luqi Huang
- China Academy of Chinese Medical Sciences, Beijing, China
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40
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Adamson PJ, Wang JJ, Anosova NG, Colella AD, Chataway TK, Kleanthous H, Gordon TP, Gordon DL. Proteomic profiling of precipitated Clostridioides difficile toxin A and B antibodies. Vaccine 2019; 38:2077-2087. [PMID: 31718902 DOI: 10.1016/j.vaccine.2019.10.096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/24/2019] [Accepted: 10/29/2019] [Indexed: 01/01/2023]
Abstract
Clostridioides difficile infection is the leading cause of nosocomial diarrhoea globally. Immune responses to toxins produced by C. difficile are important in disease progression and outcome. Here, we analysed the anti-toxin A and anti-toxin B serum antibody proteomes following natural infection or vaccination with a C. difficile toxoid A/toxoid B vaccine using a modified miniaturised proteomic approach based on de novo mass spectrometric sequencing. Analysis of immunoglobulin variable region (IgV) subfamily expression in immunoprecipitated toxin A and toxin B antibodies from four and seven participants of a vaccine trial, respectively, revealed a polyclonal proteome with restricted IGHV, IGKV and IGLV subfamily usage. No dominant IGHV subfamily was observed in the toxin A response, however the dominant anti-toxin B heavy (H)-chain was encoded by IGHV3-23. Light (L)-chain usage was convergent for both anti-toxin A and anti-toxin B proteomes with IGKV3-11, 3-15, 3-20 and 4-1 shared among all subjects in both cohorts. Peptide mapping of common IgV families showed extensive public and private amino acid substitutions. The cohort responses to toxin A and toxin B showed limited similarity in shared IGHV subfamilies. L-chain subfamily usage was more similar in the anti-toxin A and anti-toxin B responses, however the mutational signatures for each subfamily were toxin-dependent. Samples taken both post vaccination (n = 5) or at baseline, indicating previous exposure (n = 2), showed similar anti-toxin B IgV subfamily usage and mutational profiles. In summary, this study provides the first sequence-based proteomic analysis of the antibody response to the major disease-mediating toxins of C. difficile, toxin A and toxin B, and demonstrates that despite the potential for extreme diversity, the immunoglobulin repertoire can raise convergent responses to specific pathogens whether through natural infection or following vaccination.
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Affiliation(s)
- Penelope J Adamson
- Department of Microbiology and Infectious Diseases, Flinders University and SA Pathology, Flinders Medical Centre, Bedford Park, SA 5042, Australia.
| | - Jing J Wang
- Department of Immunology, Flinders University and SA Pathology, Flinders Medical Centre, Bedford Park, SA 5042, Australia.
| | | | - Alex D Colella
- Flinders Proteomic Facility, Flinders University, Flinders Medical Centre, Bedford Park, SA 5042, Australia.
| | - Timothy K Chataway
- Flinders Proteomic Facility, Flinders University, Flinders Medical Centre, Bedford Park, SA 5042, Australia.
| | | | - Tom P Gordon
- Department of Immunology, Flinders University and SA Pathology, Flinders Medical Centre, Bedford Park, SA 5042, Australia.
| | - David L Gordon
- Department of Microbiology and Infectious Diseases, Flinders University and SA Pathology, Flinders Medical Centre, Bedford Park, SA 5042, Australia.
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41
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Peng Z, Simeon R, Mitchell SB, Zhang J, Feng H, Chen Z. Designed Ankyrin Repeat Protein (DARPin) Neutralizers of TcdB from Clostridium difficile Ribotype 027. mSphere 2019; 4:e00596-19. [PMID: 31578248 PMCID: PMC6796971 DOI: 10.1128/msphere.00596-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 09/11/2019] [Indexed: 02/08/2023] Open
Abstract
Clostridium difficile infection (CDI) is a leading cause of hospital-acquired diarrhea. In recent decades, the emergence of the "hypervirulent" BI/NAP1/027 strains of C. difficile significantly increased the morbidity and mortality of CDI. The pathogenesis of CDI is primarily mediated by the action of two toxins, TcdA and TcdB, with TcdB being the major virulent factor in humans. In this report, we describe the engineering of a panel of designed ankyrin repeat proteins (DARPins) that potently neutralize TcdB from the BI/NAP1/027 strains (e.g., TcdBUK1). The most effective DARPin, D16, inhibits TcdBUK1 with a 50% effective concentration (EC50) of 0.5 nM, which is >66-fold lower than that of the FDA-approved anti-TcdB antibody bezlotoxumab (EC50, ∼33 nM). Competitive enzyme-linked immunosorbent assays (ELISAs) showed that D16 blocks interactions between TcdB and its receptor, chondroitin sulfate proteoglycan 4 (CSPG4). The dimeric DARPin U3D16, which pairs D16 with DARPin U3, a disrupter of the interaction of TcdB with Frizzled 1/2/7 receptor, exhibits 10-fold-to-20-fold-enhanced neutralization potency against TcdB from C. difficile strains VPI 10463 (laboratory strain) and M68 (CF/NAP9/017) but identical activity against TcdBUK1 relative to D16. Subsequent ELISAs revealed that TcdBUK1 did not significantly interact with Frizzled 1/2/7. Computation modeling revealed 4 key differences at the Frizzled 1/2/7 binding interface which are likely responsible for the significantly reduced binding affinity.IMPORTANCE We report the engineering and characterization of designed ankyrin proteins as potent neutralizers of TcdB toxin secreted by a hypervirulent ribotype 027 strain of Clostridium difficile We further show that although TcdB toxins from both ribotype 027 and VPI 10461 interact efficiently with TcdB receptors CSPG4 and Pvrl3, TcdB027 lacks significant ability to bind the only known physiologically relevant TcdB receptor, Frizzled 1/2/7.
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Affiliation(s)
- Zeyu Peng
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, USA
| | - Rudo Simeon
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, USA
| | - Samuel B Mitchell
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, USA
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Hanping Feng
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, USA
| | - Zhilei Chen
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, USA
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Omersa N, Podobnik M, Anderluh G. Inhibition of Pore-Forming Proteins. Toxins (Basel) 2019; 11:E545. [PMID: 31546810 PMCID: PMC6784129 DOI: 10.3390/toxins11090545] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/27/2019] [Accepted: 09/10/2019] [Indexed: 12/16/2022] Open
Abstract
Perforation of cellular membranes by pore-forming proteins can affect cell physiology, tissue integrity, or immune response. Since many pore-forming proteins are toxins or highly potent virulence factors, they represent an attractive target for the development of molecules that neutralize their actions with high efficacy. There has been an assortment of inhibitors developed to specifically obstruct the activity of pore-forming proteins, in addition to vaccination and antibiotics that serve as a plausible treatment for the majority of diseases caused by bacterial infections. Here we review a wide range of potential inhibitors that can specifically and effectively block the activity of pore-forming proteins, from small molecules to more specific macromolecular systems, such as synthetic nanoparticles, antibodies, antibody mimetics, polyvalent inhibitors, and dominant negative mutants. We discuss their mechanism of inhibition, as well as advantages and disadvantages.
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Affiliation(s)
- Neža Omersa
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
| | - Marjetka Podobnik
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
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Chen P, Lam KH, Liu Z, Mindlin FA, Chen B, Gutierrez CB, Huang L, Zhang Y, Hamza T, Feng H, Matsui T, Bowen ME, Perry K, Jin R. Structure of the full-length Clostridium difficile toxin B. Nat Struct Mol Biol 2019; 26:712-719. [PMID: 31308519 PMCID: PMC6684407 DOI: 10.1038/s41594-019-0268-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/07/2019] [Indexed: 01/07/2023]
Abstract
Clostridium difficile is an opportunistic pathogen that establishes in the colon when the gut microbiota are disrupted by antibiotics or disease. C. difficile infection (CDI) is largely caused by two virulence factors, TcdA and TcdB. Here, we report a 3.87-Å-resolution crystal structure of TcdB holotoxin that captures a unique conformation of TcdB at endosomal pH. Complementary biophysical studies suggest that the C-terminal combined repetitive oligopeptides (CROPs) domain of TcdB is dynamic and can sample open and closed conformations that may facilitate modulation of TcdB activity in response to environmental and cellular cues during intoxication. Furthermore, we report three crystal structures of TcdB-antibody complexes that reveal how antibodies could specifically inhibit the activities of individual TcdB domains. Our studies provide novel insight into the structure and function of TcdB holotoxin and identify intrinsic vulnerabilities that could be exploited to develop new therapeutics and vaccines for the treatment of CDI.
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Affiliation(s)
- Peng Chen
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA
| | - Kwok-Ho Lam
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA
| | - Zheng Liu
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA
| | - Frank A Mindlin
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Baohua Chen
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA
| | - Craig B Gutierrez
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA
| | - Yongrong Zhang
- Department of Microbial Pathogenesis, University of Maryland Baltimore, Baltimore, MD, USA
| | - Therwa Hamza
- Department of Microbial Pathogenesis, University of Maryland Baltimore, Baltimore, MD, USA
| | - Hanping Feng
- Department of Microbial Pathogenesis, University of Maryland Baltimore, Baltimore, MD, USA
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, USA
| | - Mark E Bowen
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Kay Perry
- NE-CAT and Department of Chemistry and Chemical Biology, Cornell University, Argonne National Laboratory, Argonne, IL, USA
| | - Rongsheng Jin
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA.
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44
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Pizarro-Guajardo M, Chamorro-Veloso N, Vidal RM, Paredes-Sabja D. New insights for vaccine development against Clostridium difficile infections. Anaerobe 2019; 58:73-79. [DOI: 10.1016/j.anaerobe.2019.04.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 04/17/2019] [Accepted: 04/25/2019] [Indexed: 02/08/2023]
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45
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Simeon R, Jiang M, Chamoun-Emanuelli AM, Yu H, Zhang Y, Meng R, Peng Z, Jakana J, Zhang J, Feng H, Chen Z. Selection and characterization of ultrahigh potency designed ankyrin repeat protein inhibitors of C. difficile toxin B. PLoS Biol 2019; 17:e3000311. [PMID: 31233493 PMCID: PMC6590788 DOI: 10.1371/journal.pbio.3000311] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 05/20/2019] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile infection (CDI) is a major nosocomial disease associated with significant morbidity and mortality. The pathology of CDI stems primarily from the 2 C. difficile-secreted exotoxins-toxin A (TcdA) and toxin B (TcdB)-that disrupt the tight junctions between epithelial cells leading to the loss of colonic epithelial barrier function. Here, we report the engineering of a series of monomeric and dimeric designed ankyrin repeat proteins (DARPins) for the neutralization of TcdB. The best dimeric DARPin, DLD-4, inhibited TcdB with a half maximal effective concentration (EC50) of 4 pM in vitro, representing an approximately 330-fold higher potency than the Food and Drug Administration (FDA)-approved anti-TcdB monoclonal antibody bezlotoxumab in the same assay. DLD-4 also protected mice from a toxin challenge in vivo. Cryo-electron microscopy (cryo-EM) studies revealed that the 2 constituent DARPins of DLD-4-1.4E and U3-bind the central and C-terminal regions of the delivery domain of TcdB. Competitive enzyme-linked immunosorbent assay (ELISA) studies showed that the DARPins 1.4E and U3 interfere with the interaction between TcdB and its receptors chondroitin sulfate proteoglycan 4 (CSPG4) and frizzled class receptor 2 (FZD2), respectively. Our cryo-EM studies revealed a new conformation of TcdB (both apo- and DARPin-bound at pH 7.4) in which the combined repetitive oligopeptides (CROPS) domain points away from the delivery domain. This conformation of the CROPS domain is in stark contrast to that seen in the negative-stain electron microscopy (EM) structure of TcdA and TcdB at the same pH, in which the CROPS domain bends toward and "kisses" the delivery domain. The ultrapotent anti-TcdB molecules from this study serve as candidate starting points for CDI drug development and provide new biological tools for studying the pathogenicity of C. difficile. The structural insights regarding both the "native" conformation of TcdB and the putative sites of TcdB interaction with the FZD2 receptor, in particular, should help accelerate the development of next-generation anti-C. difficile toxin therapeutics.
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Affiliation(s)
- Rudo Simeon
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Mengqiu Jiang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Ana M. Chamoun-Emanuelli
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Hua Yu
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United Sates of America
| | - Yongrong Zhang
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United Sates of America
| | - Ran Meng
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Zeyu Peng
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, United States of America
| | - Joanita Jakana
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Hanping Feng
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United Sates of America
| | - Zhilei Chen
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, United States of America
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Cole LE, Li L, Jetley U, Zhang J, Pacheco K, Ma F, Zhang J, Mundle S, Yan Y, Barone L, Rogers C, Beltraminelli N, Quemeneur L, Kleanthous H, Anderson SF, Anosova NG. Deciphering the domain specificity of C. difficile toxin neutralizing antibodies. Vaccine 2019; 37:3892-3901. [PMID: 31122858 DOI: 10.1016/j.vaccine.2019.05.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/10/2019] [Accepted: 05/13/2019] [Indexed: 12/21/2022]
Abstract
Clostridium difficile infection (CDI) is the principal cause of nosocomial diarrhea and pseudomembranous colitis associated with antibiotic therapy. The pathological effects of CDI are primarily attributed to toxins A (TcdA) and B (TcdB). Adequate toxin-specific antibody responses are associated with asymptomatic carriage, whereas insufficient humoral responses are associated with recurrent CDI. While the data supporting the importance of anti-toxin antibodies are substantial, clarity about the toxin domain specificity of these antibodies is more limited. To investigate this matter, combinations of human mAbs targeting multiple domains of TcdB were assessed using toxin neutralization assays. These data revealed that a combination of mAbs specific to all major toxin domains had improved neutralizing potency when compared to equivalent concentrations of a single mAb or a combination of mAbs against one or two domains. The function and toxin domain binding specificity of serum antibodies elicited by immunization of hamsters with a toxoid vaccine candidate was also assessed. Immunization with a toxoid vaccine candidate provoked toxin neutralizing antibodies specific to multiple domains of both TcdA and TcdB. When assessed in a toxin neutralization assay, polyclonal sera displayed greater activity against elevated concentrations of toxins than equivalent concentrations of individual mAbs. These data suggest a potential benefit of any antibody based therapeutic or prophylactic treatment that targets multiple toxin domains.
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Affiliation(s)
- Leah E Cole
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA
| | - Lu Li
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA
| | - Utsav Jetley
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA; Momenta Pharmaceuticals, INC., Research, 675 W Kendall St, Cambridge, MA 02142, USA
| | - Jinrong Zhang
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA
| | - Kristl Pacheco
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA
| | - Fuqin Ma
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA
| | - Jianxin Zhang
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA
| | - Sophia Mundle
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA
| | - Yanhua Yan
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA
| | - Lucianna Barone
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA; Harvard Vanguard Medical Associates, 230 Worcester Street, Wellesley, MA 02481, USA
| | - Christopher Rogers
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA; Maine Medical Center, Department of Pediatrics, 22 Bramhall Street, Portland, ME 04102, USA
| | - Nicola Beltraminelli
- BliNK Biomedical SAS, R&D, Gerland Plaza Techsud, 70, rue Saint Jean de Dieu, 69007 Lyon, France
| | - Laurence Quemeneur
- Sanofi Pasteur, Research Europe, 1541, Avenue Marcel Mérieux, 68280 Marcy l'Etoile, France
| | - Harry Kleanthous
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA
| | - Stephen F Anderson
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA; Anokion US, Inc., Development and Analytics, 50 Hampshire Street, Cambridge, MA 02139, USA
| | - Natalie G Anosova
- Sanofi Pasteur, Research North America, 38 Sidney Street, Cambridge, MA 02139, USA.
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Abstract
Bezlotoxumab (Zinplava™) is a fully human monoclonal antibody against Clostridium difficile toxin B indicated for the prevention of C. difficile infection (CDI) recurrence in patients with a high recurrence risk. It is the first agent approved for recurrence prevention and is administered as a single intravenous infusion in conjunction with standard-of-care (SoC) antibacterial treatment for CDI. In well-designed, placebo-controlled, phase 3 trials (MODIFY 1 and 2), a single infusion of bezlotoxumab, given in combination with SoC antibacterial therapy for CDI in adults, was effective in reducing CDI recurrence in the 12 weeks post-treatment, with this benefit being seen mainly in the patients at high recurrence risk. Bezlotoxumab did not impact the efficacy of the antibacterials being used to treat the CDI and, consistent with its benefits on CDI recurrence, appeared to reduce the need for subsequent antibacterials, thus minimizing further gut microbiota disruption. Longer term, there were no further CDI recurrences over 12 months' follow-up among patients who had received bezlotoxumab in MODIFY 2 and entered an extension substudy. Bezlotoxumab has low immunogenicity and is generally well tolerated, although the potential for heart failure in some patients requires consideration; cost-effectiveness data for bezlotoxumab are awaited with interest. Thus, a single intravenous infusion of bezlotoxumab during SoC antibacterial treatment for CDI is an emerging option for reducing CDI recurrence in adults at high risk of recurrence.
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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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49
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Hussack G, Ryan S, van Faassen H, Rossotti M, MacKenzie CR, Tanha J. Neutralization of Clostridium difficile toxin B with VHH-Fc fusions targeting the delivery and CROPs domains. PLoS One 2018; 13:e0208978. [PMID: 30540857 PMCID: PMC6291252 DOI: 10.1371/journal.pone.0208978] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 11/28/2018] [Indexed: 02/08/2023] Open
Abstract
An increasing number of antibody-based therapies are being considered for controlling bacterial infections, including Clostridium difficile by targeting toxins A and B. In an effort to develop novel C. difficile immunotherapeutics, we previously isolated several single-domain antibodies (VHHs) capable of toxin A neutralization through recognition of the extreme C-terminal combined repetitive oligopeptides (CROPs) domain, but failed at identifying neutralizing VHHs that bound a similar region on toxin B. Here we report the isolation of a panel of 29 VHHs targeting at least seven unique epitopes on a toxin B immunogen composed of a portion of the central delivery domain and the entire CROPs domain. Despite monovalent affinities as high as KD = 70 pM, none of the VHHs tested were capable of toxin B neutralization; however, modest toxin B inhibition was observed with VHH-VHH dimers and to a much greater extent with VHH-Fc fusions, reaching the neutralizing potency of the recently approved anti-toxin B monoclonal antibody bezlotoxumab in in vitro assays. Epitope binning revealed that several VHH-Fcs bound toxin B at sites distinct from the region recognized by bezlotoxumab, while other VHH-Fcs partially competed with bezlotoxumab for toxin binding. Therefore, the VHHs described here are effective at toxin B neutralization when formatted as bivalent VHH-Fc fusions by targeting toxin B at regions both similar and distinct from the bezlotoxumab binding site.
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Affiliation(s)
- Greg Hussack
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
- * E-mail:
| | - Shannon Ryan
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Henk van Faassen
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Martin Rossotti
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - C. Roger MacKenzie
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Jamshid Tanha
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
- School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada
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50
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Fühner V, Heine PA, Helmsing S, Goy S, Heidepriem J, Loeffler FF, Dübel S, Gerhard R, Hust M. Development of Neutralizing and Non-neutralizing Antibodies Targeting Known and Novel Epitopes of TcdB of Clostridioides difficile. Front Microbiol 2018; 9:2908. [PMID: 30574127 PMCID: PMC6291526 DOI: 10.3389/fmicb.2018.02908] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/13/2018] [Indexed: 12/18/2022] Open
Abstract
Clostridioides difficile is the causative bacterium in 15-20% of all antibiotic associated diarrheas. The symptoms associated with C. difficile infection (CDI) are primarily induced by the two large exotoxins TcdA and TcdB. Both toxins enter target cells by receptor-mediated endocytosis. Although different toxin receptors have been identified, it is no valid therapeutic option to prevent receptor endocytosis. Therapeutics, such as neutralizing antibodies, directly targeting both toxins are in development. Interestingly, only the anti-TcdB antibody bezlotoxumab but not the anti-TcdA antibody actoxumab prevented recurrence of CDI in clinical trials. In this work, 31 human antibody fragments against TcdB were selected by antibody phage display from the human naive antibody gene libraries HAL9/10. These antibody fragments were further characterized by in vitro neutralization assays. The epitopes of the neutralizing and non-neutralizing antibody fragments were analyzed by domain mapping, TcdB fragment phage display, and peptide arrays, to identify neutralizing and non-neutralizing epitopes. A new neutralizing epitope within the glucosyltransferase domain of TcdB was identified, providing new insights into the relevance of different toxin regions in respect of neutralization and toxicity.
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Affiliation(s)
- Viola Fühner
- Department Biotechnology, Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Philip Alexander Heine
- Department Biotechnology, Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Saskia Helmsing
- Department Biotechnology, Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Sebastian Goy
- Institute for Toxicology, Hannover Medical School, Hannover, Germany
| | - Jasmin Heidepriem
- Department Synthetic Array Technologies, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Felix F. Loeffler
- Department Synthetic Array Technologies, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Stefan Dübel
- Department Biotechnology, Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Ralf Gerhard
- Institute for Toxicology, Hannover Medical School, Hannover, Germany
| | - Michael Hust
- Department Biotechnology, Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany
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