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Zbylicki BR, Murphy CE, Petsche JA, Müh U, Dobrila HA, Ho TD, Daum MN, Pannullo AG, Weiss DS, Ellermeier CD. Identification of Clostridioides difficile mutants with increased daptomycin resistance. J Bacteriol 2024; 206:e0036823. [PMID: 38376203 PMCID: PMC10955854 DOI: 10.1128/jb.00368-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/20/2024] [Indexed: 02/21/2024] Open
Abstract
Daptomycin is a cyclic lipopeptide antibiotic used to treat infections caused by some Gram-positive bacteria. Daptomycin disrupts synthesis of the peptidoglycan (PG) cell wall by inserting into the cytoplasmic membrane and binding multiple forms of the undecaprenyl carrier lipid required for PG synthesis. Membrane insertion requires phosphatidylglycerol, so studies of daptomycin can provide insight into assembly and maintenance of the cytoplasmic membrane. Here, we studied the effects of daptomycin on Clostridioides difficile, the leading cause of healthcare-associated diarrhea. We observed that growth of C. difficile strain R20291 in the presence of sub-MIC levels of daptomycin resulted in a chaining phenotype, minicell formation, and lysis-phenotypes broadly consistent with perturbation of membranes and PG synthesis. We also selected for and characterized eight mutants with elevated daptomycin resistance. The mutations in these mutants were mapped to four genes: cdsA (cdr20291_2041), ftsH2 (cdr20291_3396), esrR (cdr20291_1187), and draS (cdr20291_2456). Of these four genes, only draS has been characterized previously. Follow-up studies indicate these mutations confer daptomycin resistance by two general mechanisms: reducing the amount of phosphatidylglycerol in the cytoplasmic membrane (cdsA) or altering the regulation of membrane processes (ftsH2, esrR, and draS). Thus, the mutants described here provide insights into phospholipid synthesis and identify signal transduction systems involved in cell envelope biogenesis and stress response in C. difficile. IMPORTANCE C. difficile is the leading cause of healthcare-associated diarrhea and is a threat to public health due to the risk of recurrent infections. Understanding biosynthesis of the atypical cell envelope of C. difficile may provide insight into novel drug targets to selectively inhibit C. difficile. Here, we identified mutations that increased daptomycin resistance and allowed us to better understand phospholipid synthesis, cell envelope biogenesis, and stress response in C. difficile.
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Affiliation(s)
- Brianne R. Zbylicki
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, Iowa, USA
| | - Claire E. Murphy
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, Iowa, USA
| | - Jennifer A. Petsche
- Interdisciplinary Graduate Program in Molecular Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Ute Müh
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, Iowa, USA
| | - Horia A. Dobrila
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, Iowa, USA
| | - Theresa D. Ho
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, Iowa, USA
| | - Mikaela N. Daum
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, Iowa, USA
| | - Anthony G. Pannullo
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, Iowa, USA
| | - David S. Weiss
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, Iowa, USA
| | - Craig D. Ellermeier
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, Iowa, USA
- Graduate Program in Genetics, University of Iowa, Iowa City, Iowa, USA
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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: 26] [Impact Index Per Article: 26.0] [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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Chen C, Dong S, Yu Z, Qiao Y, Li J, Ding X, Li R, Lin J, Bayer EA, Liu YJ, Cui Q, Feng Y. Essential autoproteolysis of bacterial anti-σ factor RsgI for transmembrane signal transduction. SCIENCE ADVANCES 2023; 9:eadg4846. [PMID: 37418529 PMCID: PMC10328401 DOI: 10.1126/sciadv.adg4846] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 06/06/2023] [Indexed: 07/09/2023]
Abstract
Autoproteolysis has been discovered to play key roles in various biological processes, but functional autoproteolysis has been rarely reported for transmembrane signaling in prokaryotes. In this study, an autoproteolytic effect was discovered in the conserved periplasmic domain of anti-σ factor RsgIs from Clostridium thermocellum, which was found to transmit extracellular polysaccharide-sensing signals into cells for regulation of the cellulosome system, a polysaccharide-degrading multienzyme complex. Crystal and NMR structures of periplasmic domains from three RsgIs demonstrated that they are different from all known proteins that undergo autoproteolysis. The RsgI-based autocleavage site was located at a conserved Asn-Pro motif between the β1 and β2 strands in the periplasmic domain. This cleavage was demonstrated to be essential for subsequent regulated intramembrane proteolysis to activate the cognate SigI, in a manner similar to that of autoproteolysis-dependent activation of eukaryotic adhesion G protein-coupled receptors. These results indicate the presence of a unique prevalent type of autoproteolytic phenomenon in bacteria for signal transduction.
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Affiliation(s)
- Chao Chen
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sheng Dong
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhaoli Yu
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai 200438, China
| | - Yichen Qiao
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Li
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoke Ding
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Renmin Li
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinzhong Lin
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai 200438, China
| | - Edward A. Bayer
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Life Sciences and The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 8499000, Israel
| | - Ya-Jun Liu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingang Feng
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Bradshaw WJ, Roberts AK, Shone CC, Acharya KR. The structure of the S-layer of Clostridium difficile. J Cell Commun Signal 2018; 12:319-331. [PMID: 29170885 PMCID: PMC5842191 DOI: 10.1007/s12079-017-0429-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/25/2017] [Indexed: 12/28/2022] Open
Abstract
The nosocomially acquired pathogen Clostridium difficile is the primary causative agent of antibiotic associated diarrhoea and causes tens of thousands of deaths globally each year. C. difficile presents a paracrystalline protein array on the surface of the cell known as an S-layer. S-layers have been demonstrated to possess a wide range of important functions, which, combined with their inherent accessibility, makes them a promising drug target. The unusually complex S-layer of C. difficile is primarily comprised of the high- and low- molecular weight S-layer proteins, HMW SLP and LMW SLP, formed from the cleavage of the S-layer precursor protein, SlpA, but may also contain up to 28 SlpA paralogues. A model of how the S-layer functions as a whole is required if it is to be exploited in fighting the bacterium. Here, we provide a summary of what is known about the S-layer of C. difficile and each of the paralogues and, considering some of the domains present, suggest potential roles for them.
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Affiliation(s)
- William J Bradshaw
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
- Public Health England, Porton Down, Salisbury, SP4 0JG, UK
| | | | | | - K Ravi Acharya
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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Itoh T, Hibi T, Suzuki F, Sugimoto I, Fujiwara A, Inaka K, Tanaka H, Ohta K, Fujii Y, Taketo A, Kimoto H. Crystal Structure of Chitinase ChiW from Paenibacillus sp. str. FPU-7 Reveals a Novel Type of Bacterial Cell-Surface-Expressed Multi-Modular Enzyme Machinery. PLoS One 2016; 11:e0167310. [PMID: 27907169 PMCID: PMC5132251 DOI: 10.1371/journal.pone.0167310] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 11/13/2016] [Indexed: 12/03/2022] Open
Abstract
The Gram-positive bacterium Paenibacillus sp. str. FPU-7 effectively hydrolyzes chitin by using a number of chitinases. A unique chitinase with two catalytic domains, ChiW, is expressed on the cell surface of this bacterium and has high activity towards various chitins, even crystalline chitin. Here, the crystal structure of ChiW at 2.1 Å resolution is presented and describes how the enzyme degrades chitin on the bacterial cell surface. The crystal structure revealed a unique multi-modular architecture composed of six domains to function efficiently on the cell surface: a right-handed β-helix domain (carbohydrate-binding module family 54, CBM-54), a Gly-Ser-rich loop, 1st immunoglobulin-like (Ig-like) fold domain, 1st β/α-barrel catalytic domain (glycoside hydrolase family 18, GH-18), 2nd Ig-like fold domain and 2nd β/α-barrel catalytic domain (GH-18). The structure of the CBM-54, flexibly linked to the catalytic region of ChiW, is described here for the first time. It is similar to those of carbohydrate lyases but displayed no detectable carbohydrate degradation activities. The CBM-54 of ChiW bound to cell wall polysaccharides, such as chin, chitosan, β-1,3-glucan, xylan and cellulose. The structural and biochemical data obtained here also indicated that the enzyme has deep and short active site clefts with endo-acting character. The affinity of CBM-54 towards cell wall polysaccharides and the degradation pattern of the catalytic domains may help to efficiently decompose the cell wall chitin through the contact surface. Furthermore, we clarify that other Gram-positive bacteria possess similar cell-surface-expressed multi-modular enzymes for cell wall polysaccharide degradation.
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Affiliation(s)
- Takafumi Itoh
- Department of Bioscience, Fukui Prefectural University, Yoshida-gun, Fukui, Japan
- * E-mail: (TI); (HK)
| | - Takao Hibi
- Department of Bioscience, Fukui Prefectural University, Yoshida-gun, Fukui, Japan
| | - Fumiko Suzuki
- Department of Bioscience, Fukui Prefectural University, Yoshida-gun, Fukui, Japan
| | - Ikumi Sugimoto
- Department of Bioscience, Fukui Prefectural University, Yoshida-gun, Fukui, Japan
| | - Akihiro Fujiwara
- Department of Bioscience, Fukui Prefectural University, Yoshida-gun, Fukui, Japan
| | - Koji Inaka
- Maruwa Foods and Biosciences Inc., Yamatokoriyama, Nara, Japan
| | | | - Kazunori Ohta
- Japan Aerospace Exploration Agency, Tsukuba, Ibaraki, Japan
| | - Yutaka Fujii
- Department of Molecular Biology and Chemistry, Faculty of Medicine, University of Fukui, Yoshida-gun, Fukui, Japan
| | - Akira Taketo
- Department of Environmental and Biotechnological Frontier Engineering, Fukui University of Technology, Fukui, Fukui, Japan
| | - Hisashi Kimoto
- Department of Bioscience, Fukui Prefectural University, Yoshida-gun, Fukui, Japan
- * E-mail: (TI); (HK)
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6
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Kirk JA, Banerji O, Fagan RP. Characteristics of the Clostridium difficile cell envelope and its importance in therapeutics. Microb Biotechnol 2016; 10:76-90. [PMID: 27311697 PMCID: PMC5270738 DOI: 10.1111/1751-7915.12372] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/26/2016] [Accepted: 05/30/2016] [Indexed: 01/08/2023] Open
Abstract
Clostridium difficile infection (CDI) is a challenging threat to human health. Infections occur after disruption of the normal microbiota, most commonly through the use of antibiotics. Current treatment for CDI largely relies on the broad‐spectrum antibiotics vancomycin and metronidazole that further disrupt the microbiota resulting in frequent recurrence, highlighting the need for C. difficile‐specific antimicrobials. The cell surface of C. difficile represents a promising target for the development of new drugs. C. difficile possesses a highly deacetylated peptidoglycan cell wall containing unique secondary cell wall polymers. Bound to the cell wall is an essential S‐layer, formed of SlpA and decorated with an additional 28 related proteins. In addition to the S‐layer, many other cell surface proteins have been identified, including several with roles in host colonization. This review aims to summarize our current understanding of these different C. difficile cell surface components and their viability as therapeutic targets.
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Affiliation(s)
- Joseph A Kirk
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
| | - Oishik Banerji
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
| | - Robert P Fagan
- Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
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7
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Janoir C. Virulence factors of Clostridium difficile and their role during infection. Anaerobe 2016; 37:13-24. [DOI: 10.1016/j.anaerobe.2015.10.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/16/2015] [Accepted: 10/21/2015] [Indexed: 02/08/2023]
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Willing SE, Richards EJ, Sempere L, Dale AG, Cutting SM, Fairweather NF. Increased toxin expression in a Clostridium difficile mfd mutant. BMC Microbiol 2015; 15:280. [PMID: 26679502 PMCID: PMC4683965 DOI: 10.1186/s12866-015-0611-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 12/03/2015] [Indexed: 12/18/2022] Open
Abstract
Background The symptoms of Clostridium difficile infection are mediated primarily by two toxins, TcdA and TcdB, the expression of which is governed by a multitude of factors including nutrient availability, growth phase and cell stress. Several global regulators have been implicated in the regulation of toxin expression, such as CcpA and CodY. Results During attempts to insertionally inactivate a putative secondary cell wall polysaccharide synthesis gene, we obtained several mutants containing off-target insertions. One mutant displayed an unusual branched colony morphology and was investigated further. Marker recovery revealed an insertion in mfd, a gene encoding a transcription-coupled repair factor. The mfd mutant exhibited pleiotropic effects, in particular increased expression of both toxin A and B (TcdA and TcdB) compared to the parental strain. Western blotting and cellular cytotoxicity assays revealed increased expression across all time points over a 24 h period, with inactivation of mfd resulting in at least a 10 fold increase in cell cytotoxicity. qRT-PCR demonstrated the upregulation of both toxins occurred on a transcriptional level. All effects of the mfd mutation were complemented by a plasmid-encoded copy of mfd, showing the effects are not due to polar effects of the intron insertion or to second site mutations. Conclusions This study adds Mfd to the repertoire of factors involved in regulation of toxin expression in Clostridium difficile. Mfd is known to remove RNA polymerase molecules from transcriptional sites where it has stalled due to repressor action, preventing transcriptional read through. The consistently high levels of toxin in the C. difficile mfd mutant indicate this process is inefficient leading to transcriptional de-repression.
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Affiliation(s)
- Stephanie E Willing
- Department of Life Sciences, Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK. .,School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
| | - Emma J Richards
- Department of Life Sciences, Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK.
| | - Lluis Sempere
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
| | - Aaron G Dale
- Department of Life Sciences, Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK.
| | - Simon M Cutting
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
| | - Neil F Fairweather
- Department of Life Sciences, Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK.
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Ünal CM, Steinert M. Novel therapeutic strategies for Clostridium difficile infections. Expert Opin Ther Targets 2015; 20:269-85. [PMID: 26565670 DOI: 10.1517/14728222.2016.1090428] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION In recent years, Clostridium difficile has become the primary cause of antibiotic-associated diarrhea and pseudomembranous colitis, resulting in long and complicated hospital stays that represent a serious burden for patients as well as health care systems. Currently, conservative treatment of C. difficile infection (CDI) relies on the antibiotics vancomycin, metronidazole or fidaxomicin, or in case of multiple recurrences, fecal microbiota transplantation (FMT). AREAS COVERED The fast-spreading, epidemic nature of this pathogen urgently necessitates the search for alternative treatment strategies as well as antibiotic targets. Accordingly, in this review, we highlight the recent findings regarding virulence associated traits of C. difficile, evaluate their potential as alternative drug targets, and present current efforts in designing inhibitory compounds, with the aim of pointing out possibilities for future treatment strategies. EXPERT OPINION Increased attention on systematic analysis of the virulence mechanisms of C. difficile has already led to the identification of several alternative drug targets. In the future, applying state of the art 'omics' and the development of novel infection models that mimic the human gut, a highly complex ecological niche, will unveil the genomic and metabolic plasticity of this pathogen and will certainly help dealing with future challenges.
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Affiliation(s)
- Can M Ünal
- a 1 Technische Universität Braunschweig, Institut für Mikrobiologie , Spielmannstr. 7, D-38106, Braunschweig, Germany ; .,b 2 Türk-Alman Üniversitesi, Fen Fakültesi , Şahinkaya Cad. 86, 34820, Istanbul, Turkey
| | - Michael Steinert
- a 1 Technische Universität Braunschweig, Institut für Mikrobiologie , Spielmannstr. 7, D-38106, Braunschweig, Germany ; .,c 3 Helmholtz Centre for Infection Research , Mascheroder Weg 1, 38124, Braunschweig, Germany
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Sekulovic O, Ospina Bedoya M, Fivian-Hughes AS, Fairweather NF, Fortier LC. The Clostridium difficile cell wall protein CwpV confers phase-variable phage resistance. Mol Microbiol 2015; 98:329-42. [PMID: 26179020 PMCID: PMC4737114 DOI: 10.1111/mmi.13121] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2015] [Indexed: 01/21/2023]
Abstract
Bacteriophages are present in virtually all ecosystems, and bacteria have developed multiple antiphage strategies to counter their attacks. Clostridium difficile is an important pathogen causing severe intestinal infections in humans and animals. Here we show that the conserved cell-surface protein CwpV provides antiphage protection in C. difficile. This protein, for which the expression is phase-variable, is classified into five types, each differing in their repeat-containing C-terminal domain. When expressed constitutively from a plasmid or the chromosome of locked 'ON' cells of C. difficile R20291, CwpV conferred antiphage protection. Differences in the level of phage protection were observed depending on the phage morphological group, siphophages being the most sensitive with efficiency of plaquing (EOP) values of < 5 × 10(-7) for phages ϕCD38-2, ϕCD111 and ϕCD146. Protection against the myophages ϕMMP01 and ϕCD52 was weaker, with EOP values between 9.0 × 10(-3) and 1.1 × 10(-1). The C-terminal domain of CwpV carries the antiphage activity and its deletion, or part of it, significantly reduced the antiphage protection. CwpV does not affect phage adsorption, but phage DNA replication is prevented, suggesting a mechanism reminiscent of superinfection exclusion systems normally encoded on prophages. CwpV thus represents a novel ubiquitous host-encoded and phase-variable antiphage system in C. difficile.
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Affiliation(s)
- Ognjen Sekulovic
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Maicol Ospina Bedoya
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Amanda S Fivian-Hughes
- Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - Neil F Fairweather
- Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - Louis-Charles Fortier
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
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11
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Bastiaansen KC, van Ulsen P, Wijtmans M, Bitter W, Llamas MA. Self-cleavage of the Pseudomonas aeruginosa Cell-surface Signaling Anti-sigma Factor FoxR Occurs through an N-O Acyl Rearrangement. J Biol Chem 2015; 290:12237-46. [PMID: 25809487 DOI: 10.1074/jbc.m115.643098] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Indexed: 11/06/2022] Open
Abstract
The Fox system of Pseudomonas aeruginosa is a cell-surface signaling (CSS) pathway employed by the bacterium to sense and respond to the presence of the heterologous siderophore ferrioxamine in the environment. This regulatory pathway controls the transcription of the foxA ferrioxamine receptor gene through the extracytoplasmic function sigma factor σ(FoxI). In the absence of ferrioxamine, the activity of σ(FoxI) is inhibited by the transmembrane anti-sigma factor FoxR. Upon binding of ferrioxamine by the FoxA receptor, FoxR is processed by a complex proteolytic cascade leading to the release and activation of σ(FoxI). Interestingly, we have recently shown that FoxR undergoes self-cleavage between the periplasmic Gly-191 and Thr-192 residues independent of the perception of ferrioxamine. This autoproteolytic event, which is widespread among CSS anti-sigma factors, produces two distinct domains that interact and function together to transduce the presence of the signal. In this work, we provide evidence that the self-cleavage of FoxR is not an enzyme-dependent process but is induced by an N-O acyl rearrangement. Mutation analysis showed that the nucleophilic side chain of the Thr-192 residue at +1 of the cleavage site is required for an attack on the preceding Gly-191, after which the resulting ester bond is likely hydrolyzed. Because the cleavage site is well preserved and the hydrolysis of periplasmic CSS anti-sigma factors is widely observed, we hypothesize that cleavage via an N-O acyl rearrangement is a conserved feature of these proteins.
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Affiliation(s)
- Karlijn C Bastiaansen
- From the Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada E-18008, Spain and Section of Molecular Microbiology, Department of Molecular Cell Biology and
| | - Peter van Ulsen
- Section of Molecular Microbiology, Department of Molecular Cell Biology and
| | - Maikel Wijtmans
- Division of Medicinal Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands
| | - Wilbert Bitter
- Section of Molecular Microbiology, Department of Molecular Cell Biology and
| | - María A Llamas
- From the Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada E-18008, Spain and
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Sui L, Lakshminarasimhan D, Pande S, Guo HC. Structural basis of a point mutation that causes the genetic disease aspartylglucosaminuria. Structure 2014; 22:1855-1861. [PMID: 25456816 DOI: 10.1016/j.str.2014.09.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 08/30/2014] [Accepted: 09/17/2014] [Indexed: 10/24/2022]
Abstract
Aspartylglucosaminuria (AGU) is a lysosomal storage disease caused by a metabolic disorder of lysosomes to digest Asn-linked glycoproteins. The specific enzyme linked to AGU is a lysosomal hydrolase called glycosylasparaginase. Crystallographic studies revealed that a surface loop blocks the catalytic center of the mature hydrolase. Autoproteolysis is therefore required to remove this P loop and open up the hydrolase center. Nonetheless, AGU mutations result in misprocessing of their precursors and are deficient in hydrolyzing glycoasparagines. To understand the catalytic and structural consequences of AGU mutations, we have characterized two AGU models, one corresponding to a Finnish allele and the other found in a Canadian family. We also report a 2.1 Å resolution structure of the latter AGU model. The current crystallographic study provides a high-resolution structure of an AGU mutant. It reveals substantial conformation changes at the defective autocleavage site of the AGU mutant, which is trapped as an inactive precursor.
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Affiliation(s)
- Lufei Sui
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA
| | - Damodharan Lakshminarasimhan
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA
| | - Suchita Pande
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA
| | - Hwai-Chen Guo
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA.
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