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Acciarri G, Taborra ME, Gizzi FO, Blancato VS, Magni C. Insertion sequence IS6770 modulates potassium symporter kup transcription in Enterococcus faecalis JH2-2 under low pH conditions. Int J Food Microbiol 2024; 419:110736. [PMID: 38772216 DOI: 10.1016/j.ijfoodmicro.2024.110736] [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: 01/19/2024] [Revised: 04/05/2024] [Accepted: 05/05/2024] [Indexed: 05/23/2024]
Abstract
Enterococcus faecalis is a phylogenetically and industrially relevant microorganism associated with Lactic Acid Bacteria. Some strains of this bacterium are employed as probiotics in commercial applications, while others serve as the principal component in starter cultures for artisanal regional cheese production. However, over the last decade, this species has emerged as an opportunistic multiresistant pathogen, raising concerns about its impact on human health. Recently, we identified multiple potassium transporter systems in E. faecalis, including the Ktr systems (KtrAB and KtrAD), Kup, KimA and Kdp complex (KdpFABC). Nevertheless, the physiological significance of these proteins remains not fully understood. In this study, we observed that the kup gene promoter region in the JH2-2 strain was modified due to the insertion of a complete copy of the IS6770 insertion sequence. Consequently, we investigated the influence of IS6770 on the expression of the kup gene. To achieve this, we conducted a mapping of the promoter region of this gene in the E. faecalis JH2-2 strain, employing fluorescence gene reporters. In addition, a transcriptional analysis of the kup gene was executed in a strain derived from E. faecalis V583 that lacks the IS30-related insertion element, facilitating the identification of the transcriptional start site. Next, the expression of the kup gene was evaluated via RT-qPCR under different pH stressful conditions. A strong upregulation of the kup gene was observed at an initial pH of 5.0 in the strain derived from E. faecalis V583. However, the activation of transcription was not observed in the E. faecalis JH2-2 strain due to the hindrance caused by the presence of IS6770. Besides that, our computational analysis of E. faecalis genomes elucidates a plausible association between transposition and the regulation of the kup gene. Remarkably, the ubiquitous presence of IS6770 throughout the phylogenetic tree implies its ancient existence within E. faecalis. Moreover, the recurrent co-occurrence of IS6770 with the kup gene, observed in 30 % of IS6770-positive strains, alludes to the potential involvement of this genomic arrangement in the adaptive strategies of E. faecalis across diverse niches.
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Affiliation(s)
- Giuliana Acciarri
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Suipacha 590, Rosario, Argentina; Laboratorio de Biotecnología e Inocuidad de los Alimentos, Área de Biotecnología de los Alimentos (FBioyF, UNR- Municipalidad de Granadero Baigorria), Sede Suipacha 590, Rosario, Argentina
| | - Maria Eugenia Taborra
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Suipacha 590, Rosario, Argentina; Laboratorio de Biotecnología e Inocuidad de los Alimentos, Área de Biotecnología de los Alimentos (FBioyF, UNR- Municipalidad de Granadero Baigorria), Sede Suipacha 590, Rosario, Argentina
| | - Fernan O Gizzi
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Suipacha 590, Rosario, Argentina; Laboratorio de Biotecnología e Inocuidad de los Alimentos, Área de Biotecnología de los Alimentos (FBioyF, UNR- Municipalidad de Granadero Baigorria), Sede Suipacha 590, Rosario, Argentina
| | - Victor S Blancato
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Suipacha 590, Rosario, Argentina; Laboratorio de Biotecnología e Inocuidad de los Alimentos, Área de Biotecnología de los Alimentos (FBioyF, UNR- Municipalidad de Granadero Baigorria), Sede Suipacha 590, Rosario, Argentina
| | - Christian Magni
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular y Celular de Rosario (IBR), sede Facultad de Ciencias Bioquímicas y Farmacéuticas (FBioyF), Universidad Nacional de Rosario (UNR), Consejo Nacional de Ciencia y Tecnología (CONICET), Suipacha 590, Rosario, Argentina; Laboratorio de Biotecnología e Inocuidad de los Alimentos, Área de Biotecnología de los Alimentos (FBioyF, UNR- Municipalidad de Granadero Baigorria), Sede Suipacha 590, Rosario, Argentina.
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Cassona CP, Ramalhete S, Amara K, Candela T, Kansau I, Denève-Larrazet C, Janoir-Jouveshomme C, Mota LJ, Dupuy B, Serrano M, Henriques AO. Spores of Clostridioides difficile are toxin delivery vehicles. Commun Biol 2024; 7:839. [PMID: 38987278 PMCID: PMC11237016 DOI: 10.1038/s42003-024-06521-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/28/2024] [Indexed: 07/12/2024] Open
Abstract
Clostridioides difficile causes a wide range of intestinal diseases through the action of two main cytotoxins, TcdA and TcdB. Ingested spores germinate in the intestine establishing a population of cells that produce toxins and spores. The pathogenicity locus, PaLoc, comprises several genes, including those coding for TcdA/B, for the holin-like TcdE protein, and for TcdR, an auto-regulatory RNA polymerase sigma factor essential for tcdA/B and tcdE expression. Here we show that tcdR, tcdA, tcdB and tcdE are expressed in a fraction of the sporulating cells, in either the whole sporangium or in the forespore. The whole sporangium pattern is due to protracted expression initiated in vegetative cells by σD, which primes the TcdR auto-regulatory loop. In contrast, the forespore-specific regulatory proteins σG and SpoVT control TcdR production and tcdA/tcdB and tcdE expression in this cell. We detected TcdA at the spore surface, and we show that wild type and ΔtcdA or ΔtcdB spores but not ΔtcdR or ΔtcdA/ΔtcdB spores are cytopathic against HT29 and Vero cells, indicating that spores may serve as toxin-delivery vehicles. Since the addition of TcdA and TcdB enhance binding of spores to epithelial cells, this effect may occur independently of toxin production by vegetative cells.
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Affiliation(s)
- Carolina P Cassona
- Instituto de Tecnologia Química e Biológica, NOVA University Lisbon, Oeiras, Portugal
| | - Sara Ramalhete
- Instituto de Tecnologia Química e Biológica, NOVA University Lisbon, Oeiras, Portugal
| | - Khira Amara
- Instituto de Tecnologia Química e Biológica, NOVA University Lisbon, Oeiras, Portugal
| | - Thomas Candela
- Micalis Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France
| | - Imad Kansau
- Micalis Institute, Université Paris-Saclay, INRAE, AgroParisTech, Jouy-en-Josas, France
| | | | | | - Luís Jaime Mota
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Bruno Dupuy
- Institut Pasteur, Université Paris-Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015, Paris, France
| | - Mónica Serrano
- Instituto de Tecnologia Química e Biológica, NOVA University Lisbon, Oeiras, Portugal
| | - Adriano O Henriques
- Instituto de Tecnologia Química e Biológica, NOVA University Lisbon, Oeiras, Portugal.
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Gong JJ, Huang IH, Su MSW, Xie SX, Liu WY, Huang CR, Hung YP, Wu SR, Tsai PJ, Ko WC, Chen JW. Phage transcriptional regulator X (PtrX)-mediated augmentation of toxin production and virulence in Clostridioides difficile strain R20291. Microbiol Res 2024; 280:127576. [PMID: 38183754 DOI: 10.1016/j.micres.2023.127576] [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: 10/03/2023] [Revised: 11/24/2023] [Accepted: 12/13/2023] [Indexed: 01/08/2024]
Abstract
Clostridioides difficile is a Gram-positive, anaerobic, and spore-forming bacterial member of the human gut microbiome. The primary virulence factors of C. difficile are toxin A and toxin B. These toxins damage the cell cytoskeleton and cause various diseases, from diarrhea to severe pseudomembranous colitis. Evidence suggests that bacteriophages can regulate the expression of the pathogenicity locus (PaLoc) genes of C. difficile. We previously demonstrated that the genome of the C. difficile RT027 strain NCKUH-21 contains a prophage-like DNA sequence, which was found to be markedly similar to that of the φCD38-2 phage. In the present study, we investigated the mechanisms underlying the φNCKUH-21-mediated regulation of the pathogenicity and the PaLoc genes expression in the lysogenized C. difficile strain R20291. The carriage of φNCKUH-21 in R20291 cells substantially enhanced toxin production, bacterial motility, biofilm formation, and spore germination in vitro. Subsequent mouse studies revealed that the lysogenized R20291 strain caused a more severe infection than the wild-type strain. We screened three φNCKUH-21 genes encoding DNA-binding proteins to check their effects on PaLoc genes expression. The overexpression of NCKUH-21_03890, annotated as a transcriptional regulator (phage transcriptional regulator X, PtrX), considerably enhanced toxin production, biofilm formation, and bacterial motility of R20291. Transcriptome analysis further confirmed that the overexpression of ptrX led to the upregulation of the expression of toxin genes, flagellar genes, and csrA. In the ptrX-overexpressing R20291 strain, PtrX influenced the expression of flagellar genes and the sigma factor gene sigD, possibly through an increased flagellar phase ON configuration ratio.
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Affiliation(s)
- Jun-Jia Gong
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - I-Hsiu Huang
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107, USA
| | - Marcia Shu-Wei Su
- Department of Biotechnology and Laboratory Science in Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Si-Xuan Xie
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Yong Liu
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Cheng-Rung Huang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yuan-Pin Hung
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shang-Rung Wu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Jane Tsai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan; Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan; Center for Clinical Medicine Research, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Wen-Chien Ko
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jenn-Wei Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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4
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Zeng J, Fang S, Guo J, Dong M, Tian G, Tao L. Fight or flee, a vital choice for Clostridioides difficile. MLIFE 2024; 3:14-20. [PMID: 38827507 PMCID: PMC11139204 DOI: 10.1002/mlf2.12102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/17/2023] [Accepted: 10/08/2023] [Indexed: 06/04/2024]
Abstract
Clostridioides difficile is a leading cause of healthcare-associated infections, causing billions of economic losses every year. Its symptoms range from mild diarrhea to life-threatening damage to the colon. Transmission and recurrence of C. difficile infection (CDI) are mediated by the metabolically dormant spores, while the virulence of C. difficile is mainly due to the two large clostridial toxins, TcdA and TcdB. Producing toxins or forming spores are two different strategies for C. difficile to cope with harsh environmental conditions. It is of great significance to understand the molecular mechanisms for C. difficile to skew to either of the cellular processes. Here, we summarize the current understanding of the regulation and connections between toxin production and sporulation in C. difficile and further discuss the potential solutions for yet-to-be-answered questions.
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Affiliation(s)
- Ji Zeng
- School of Biomedical and Pharmaceutical SciencesGuangdong University of TechnologyGuangzhouChina
| | - Shuying Fang
- School of Biomedical and Pharmaceutical SciencesGuangdong University of TechnologyGuangzhouChina
| | - Jinquan Guo
- Department of Brest SurgeryPanyu Central HospitalGuangzhouChina
| | - Min Dong
- Department of MicrobiologyHarvard Medical SchoolBostonMassachusettsUSA
- Department of Urology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Guo‐Bao Tian
- Department of MicrobiologyZhongshan School of Medicine, Sun Yat‐sen UniversityGuangzhouChina
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
- Key Laboratory of Tropical Diseases Control (Sun Yat‐sen University), Ministry of EducationGuangzhouChina
- School of MedicineXizang Minzu UniversityXianyangChina
| | - Liang Tao
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and BiomedicineWestlake UniversityHangzhouChina
- Research Center for Industries of the Future, School of Life SciencesWestlake UniversityHangzhouChina
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5
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Anjou C, Lotoux A, Zhukova A, Royer M, Caulat LC, Capuzzo E, Morvan C, Martin-Verstraete I. The multiplicity of thioredoxin systems meets the specific lifestyles of Clostridia. PLoS Pathog 2024; 20:e1012001. [PMID: 38330058 PMCID: PMC10880999 DOI: 10.1371/journal.ppat.1012001] [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: 09/28/2023] [Revised: 02/21/2024] [Accepted: 01/26/2024] [Indexed: 02/10/2024] Open
Abstract
Cells are unceasingly confronted by oxidative stresses that oxidize proteins on their cysteines. The thioredoxin (Trx) system, which is a ubiquitous system for thiol and protein repair, is composed of a thioredoxin (TrxA) and a thioredoxin reductase (TrxB). TrxAs reduce disulfide bonds of oxidized proteins and are then usually recycled by a single pleiotropic NAD(P)H-dependent TrxB (NTR). In this work, we first analyzed the composition of Trx systems across Bacteria. Most bacteria have only one NTR, but organisms in some Phyla have several TrxBs. In Firmicutes, multiple TrxBs are observed only in Clostridia, with another peculiarity being the existence of ferredoxin-dependent TrxBs. We used Clostridioides difficile, a pathogenic sporulating anaerobic Firmicutes, as a model to investigate the biological relevance of TrxB multiplicity. Three TrxAs and three TrxBs are present in the 630Δerm strain. We showed that two systems are involved in the response to infection-related stresses, allowing the survival of vegetative cells exposed to oxygen, inflammation-related molecules and bile salts. A fourth TrxB copy present in some strains also contributes to the stress-response arsenal. One of the conserved stress-response Trx system was found to be present both in vegetative cells and in the spores and is under a dual transcriptional control by vegetative cell and sporulation sigma factors. This Trx system contributes to spore survival to hypochlorite and ensure proper germination in the presence of oxygen. Finally, we found that the third Trx system contributes to sporulation through the recycling of the glycine-reductase, a Stickland pathway enzyme that allows the consumption of glycine and contributes to sporulation. Altogether, we showed that Trx systems are produced under the control of various regulatory signals and respond to different regulatory networks. The multiplicity of Trx systems and the diversity of TrxBs most likely meet specific needs of Clostridia in adaptation to strong stress exposure, sporulation and Stickland pathways.
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Affiliation(s)
- Cyril Anjou
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Aurélie Lotoux
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Anna Zhukova
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris, France
| | - Marie Royer
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Léo C. Caulat
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Elena Capuzzo
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Claire Morvan
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Isabelle Martin-Verstraete
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
- Institut Universitaire de France, Paris, France
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Serrano M, Martins D, Henriques AO. Clostridioides difficile Sporulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1435:273-314. [PMID: 38175480 DOI: 10.1007/978-3-031-42108-2_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Some members of the Firmicutes phylum, including many members of the human gut microbiota, are able to differentiate a dormant and highly resistant cell type, the endospore (hereinafter spore for simplicity). Spore-formers can colonize virtually any habitat and, because of their resistance to a wide variety of physical and chemical insults, spores can remain viable in the environment for long periods of time. In the anaerobic enteric pathogen Clostridioides difficile the aetiologic agent is the oxygen-resistant spore, while the toxins produced by actively growing cells are the main cause of the disease symptoms. Here, we review the regulatory circuits that govern entry into sporulation. We also cover the role of spores in the infectious cycle of C. difficile in relation to spore structure and function and the main control points along spore morphogenesis.
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Affiliation(s)
- Mónica Serrano
- Instituto de Tecnologia Química e Biológica António Xavier, Oeiras, Portugal.
| | - Diogo Martins
- Instituto de Tecnologia Química e Biológica António Xavier, Oeiras, Portugal
| | - Adriano O Henriques
- Instituto de Tecnologia Química e Biológica António Xavier, Oeiras, Portugal
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Auria E, Deschamps J, Briandet R, Dupuy B. Extracellular succinate induces spatially organized biofilm formation in Clostridioides difficile. Biofilm 2023; 5:100125. [PMID: 37214349 PMCID: PMC10192414 DOI: 10.1016/j.bioflm.2023.100125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 05/24/2023] Open
Abstract
Clostridioides difficile infection associated to gut microbiome dysbiosis is the leading cause for nosocomial diarrhea. The ability of C. difficile to form biofilms has been progressively linked to its pathogenesis as well as its persistence in the gut. Although C. difficile has been reported to form biofilms in an increasing number of conditions, little is known about how these biofilms are formed in the gut and what factors may trigger their formation. Here we report that succinate, a metabolite abundantly produced by the dysbiotic gut microbiota, induces in vitro biofilm formation of C. difficile strains. We characterized the morphology and spatial composition of succinate-induced biofilms, and compared to non-induced or deoxycholate (DCA) induced biofilms. Biofilms induced by succinate are significantly thicker, structurally more complex, and poorer in proteins and exopolysaccharides (EPS). We then applied transcriptomics and genetics to characterize the early stages of succinate-induced biofilm formation and we showed that succinate-induced biofilm results from major metabolic shifts and cell-wall composition changes. Similar to DCA-induced biofilms, biofilms induced by succinate depend on the presence of a rapidly metabolized sugar. Finally, although succinate can be consumed by the bacteria, we found that the extracellular succinate is in fact responsible for the induction of biofilm formation through complex regulation involving global metabolic regulators and the osmotic stress response. Thus, our work suggests that as a gut signal, succinate may drive biofilm formation and help persistence of C. difficile in the gut, increasing the risk of relapse.
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Affiliation(s)
- Emile Auria
- Institut Pasteur, Université Paris-Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015, Paris, France
| | - Julien Deschamps
- Institut Micalis, INRAE, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Romain Briandet
- Institut Micalis, INRAE, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Bruno Dupuy
- Institut Pasteur, Université Paris-Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015, Paris, France
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Marini E, Olivença C, Ramalhete S, Aguirre AM, Ingle P, Melo MN, Antunes W, Minton NP, Hernandez G, Cordeiro TN, Sorg JA, Serrano M, Henriques AO. A sporulation signature protease is required for assembly of the spore surface layers, germination and host colonization in Clostridioides difficile. PLoS Pathog 2023; 19:e1011741. [PMID: 37956166 PMCID: PMC10681294 DOI: 10.1371/journal.ppat.1011741] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 11/27/2023] [Accepted: 10/09/2023] [Indexed: 11/15/2023] Open
Abstract
A genomic signature for endosporulation includes a gene coding for a protease, YabG, which in the model organism Bacillus subtilis is involved in assembly of the spore coat. We show that in the human pathogen Clostridioidesm difficile, YabG is critical for the assembly of the coat and exosporium layers of spores. YabG is produced during sporulation under the control of the mother cell-specific regulators σE and σK and associates with the spore surface layers. YabG shows an N-terminal SH3-like domain and a C-terminal domain that resembles single domain response regulators, such as CheY, yet is atypical in that the conserved phosphoryl-acceptor residue is absent. Instead, the CheY-like domain carries residues required for activity, including Cys207 and His161, the homologues of which form a catalytic diad in the B. subtilis protein, and also Asp162. The substitution of any of these residues by Ala, eliminates an auto-proteolytic activity as well as interdomain processing of CspBA, a reaction that releases the CspB protease, required for proper spore germination. An in-frame deletion of yabG or an allele coding for an inactive protein, yabGC207A, both cause misassemby of the coat and exosporium and the formation of spores that are more permeable to lysozyme and impaired in germination and host colonization. Furthermore, we show that YabG is required for the expression of at least two σK-dependent genes, cotA, coding for a coat protein, and cdeM, coding for a key determinant of exosporium assembly. Thus, YabG also impinges upon the genetic program of the mother cell possibly by eliminating a transcriptional repressor. Although this activity has not been described for the B. subtilis protein and most of the YabG substrates vary among sporeformers, the general role of the protease in the assembly of the spore surface is likely to be conserved across evolutionary distance.
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Affiliation(s)
- Eleonora Marini
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República EAN, Oeiras, Portugal
| | - Carmen Olivença
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República EAN, Oeiras, Portugal
| | - Sara Ramalhete
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República EAN, Oeiras, Portugal
| | - Andrea Martinez Aguirre
- Texas A&M University, Department of Biology, College Station, Texas, United States of America
| | - Patrick Ingle
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Manuel N Melo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República EAN, Oeiras, Portugal
| | - Wilson Antunes
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República EAN, Oeiras, Portugal
| | - Nigel P Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Guillem Hernandez
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República EAN, Oeiras, Portugal
| | - Tiago N Cordeiro
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República EAN, Oeiras, Portugal
| | - Joseph A Sorg
- Texas A&M University, Department of Biology, College Station, Texas, United States of America
| | - Mónica Serrano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República EAN, Oeiras, Portugal
| | - Adriano O Henriques
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República EAN, Oeiras, Portugal
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Rizvi A, Vargas-Cuebas G, Edwards AN, DiCandia MA, Carter ZA, Lee CD, Monteiro MP, McBride SM. Glycine fermentation by C. difficile promotes virulence and spore formation, and is induced by host cathelicidin. Infect Immun 2023; 91:e0031923. [PMID: 37754683 PMCID: PMC10580938 DOI: 10.1128/iai.00319-23] [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: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 09/28/2023] Open
Abstract
Clostridioides difficile is a leading cause of antibiotic-associated diarrheal disease. C. difficile colonization, growth, and toxin production in the intestine is strongly associated with its ability to use amino acids to generate energy, but little is known about the impact of specific amino acids on C. difficile pathogenesis. The amino acid glycine is enriched in the dysbiotic gut and is suspected to contribute to C. difficile infection. We hypothesized that the use of glycine as an energy source contributes to colonization of the intestine and pathogenesis of C. difficile. To test this hypothesis, we deleted the glycine reductase (GR) genes grdAB, rendering C. difficile unable to ferment glycine, and investigated the impact on growth and pathogenesis. Our data show that the grd pathway promotes growth, toxin production, and sporulation. Glycine fermentation also had a significant impact on toxin production and pathogenesis of C. difficile in the hamster model of disease. Furthermore, we determined that the grd locus is regulated by host cathelicidin (LL-37) and the cathelicidin-responsive regulator, ClnR, indicating that the host peptide signals to control glycine catabolism. The induction of glycine fermentation by LL-37 demonstrates a direct link between the host immune response and the bacterial reactions of toxin production and spore formation.
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Affiliation(s)
- Arshad Rizvi
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, USA
| | - Germán Vargas-Cuebas
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, USA
| | - Adrianne N. Edwards
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, USA
| | - Michael A. DiCandia
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, USA
| | - Zavier A. Carter
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, USA
| | - Cheyenne D. Lee
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, USA
| | - Marcos P. Monteiro
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, USA
| | - Shonna M. McBride
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, Georgia, USA
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Wetzel D, Rizvi A, Edwards AN, McBride SM. The predicted acetoin dehydrogenase pathway represses sporulation of Clostridioides difficile. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.28.551048. [PMID: 37546766 PMCID: PMC10402147 DOI: 10.1101/2023.07.28.551048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Clostridioides difficile is a major gastrointestinal pathogen that is transmitted as a dormant spore. As an intestinal pathogen, C. difficile must contend with variable environmental conditions, including fluctuations in pH and nutrient availability. Nutrition and pH both influence growth and spore formation, but how pH and nutrition jointly influence sporulation are not known. In this study, we investigated the dual impact of pH and pH-dependent metabolism on C. difficile sporulation. Specifically, we examined the impacts of pH and the metabolite acetoin on C. difficile growth and sporulation. We found that expression of the predicted acetoin dehydrogenase operon, acoRABCL , was pH-dependent and regulated by acetoin. Regulation of the C. difficile aco locus is distinct from other characterized systems and appears to involve a co-transcribed DeoR-family regulator rather than the sigma 54 -dependent activator. In addition, an acoA null mutant produced significantly more spores and initiated sporulation earlier than the parent strain. However, unlike other Firmicutes, growth and culture density of C. difficile was not increased by acetoin availability or disruption of the aco pathway. Together, these results indicate that acetoin, pH, and the aco pathway play important roles in nutritional repression of sporulation in C. difficile , but acetoin metabolism does not support cell growth as a stationary phase energy source. IMPORTANCE Clostridioides difficile, or C. diff , is an anaerobic bacterium that lives within the gut of many mammals and causes infectious diarrhea. C. difficile is able to survive outside of the gut and transmit to new hosts by forming dormant spores. It is known that the pH of the intestine and the nutrients available both affect the growth and sporulation of C. diffiicile, but the specific conditions that result in sporulation in the host are not clear. In this study, we investigated how pH and the metabolite acetoin affect the ability of C. difficile to grow, proliferate, and form spores. We found that a mutant lacking the predicted acetoin metabolism pathway form more spores, but their growth is not impacted. These results show that C. difficile uses acetoin differently than many other species and that acetoin has an important role as an environmental metabolite that influences spore formation.
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11
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Dupuy B. Regulation of Clostridial Toxin Gene Expression: A Pasteurian Tradition. Toxins (Basel) 2023; 15:413. [PMID: 37505682 PMCID: PMC10467148 DOI: 10.3390/toxins15070413] [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: 05/09/2023] [Revised: 06/13/2023] [Accepted: 06/19/2023] [Indexed: 07/29/2023] Open
Abstract
The alarming symptoms attributed to several potent clostridial toxins enabled the early identification of the causative agent of tetanus, botulism, and gas gangrene diseases, which belongs to the most famous species of pathogenic clostridia. Although Clostridioides difficile was identified early in the 20th century as producing important toxins, it was identified only 40 years later as the causative agent of important nosocomial diseases upon the advent of antibiotic therapies in hospital settings. Today, C. difficile is a leading public health issue, as it is the major cause of antibiotic-associated diarrhea in adults. In particular, severe symptoms within the spectrum of C. difficile infections are directly related to the levels of toxins produced in the host. This highlights the importance of understanding the regulation of toxin synthesis in the pathogenicity process of C. difficile, whose regulatory factors in response to the gut environment were first identified at the Institut Pasteur. Subsequently, the work of other groups in the field contributed to further deciphering the complex mechanisms controlling toxin production triggered by the intestinal dysbiosis states during infection. This review summarizes the Pasteurian contribution to clostridial toxin regulation studies.
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Affiliation(s)
- Bruno Dupuy
- Institut Pasteur, Université Paris-Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015 Paris, France
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12
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Bosnar LM, Shindler AE, Wood J, Patch C, Franks AE. Attempts to limit sporulation in the probiotic strain Bacillus subtilis BG01-4 TM through mutation accumulation and selection. Access Microbiol 2023; 5:acmi000419. [PMID: 37323944 PMCID: PMC10267654 DOI: 10.1099/acmi.0.000419] [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: 02/10/2022] [Accepted: 03/16/2023] [Indexed: 06/17/2023] Open
Abstract
The use of bacterial spores in probiotics over viable loads of bacteria has many advantages, including the durability of spores, which allows spore-based probiotics to effectively traverse the various biochemical barriers present in the gastrointestinal tract. However, the majority of spore-based probiotics developed currently aim to treat adults, and there is a litany of differences between the adult and infant intestinal systems, including the immaturity and low microbial species diversity observed within the intestines of infants. These differences are only further exacerbated in premature infants with necrotizing enterocolitis (NEC) and indicates that what may be appropriate for an adult or even a healthy full-term infant may not be suited for an unhealthy premature infant. Complications from using spore-based probiotics for premature infants with NEC may involve the spores remaining dormant and adhering to the intestinal epithelia, the out-competing of commensal bacteria by spores, and most importantly the innate antibiotic resistance of spores. Also, the ability of Bacillus subtilis to produce spores under duress may result in less B. subtilis perishing within the intestines and releasing membrane branched-chain fatty acids. The isolate B. subtilis BG01-4TM is a proprietary strain developed by Vernx Biotechnology through accumulating mutations within the BG01-4TM genome in a serial batch culture. Strain BG01-4TM was provided as a non-spore-forming B. subtilis , but a positive sporulation status for BG01-4TM was confirmed through in vitro testing and suggested that selection for the sporulation defective genes could occur within an environment that would select against sporulation. The durability of key sporulation genes was ratified in this study, as the ability of BG01-4TM to produce spores was not eliminated by the attempts to select against sporulation genes in BG01-4TM by the epigenetic factors of high glucose and low pH. However, a variation in the genes in isolate BG01-4-8 involved in the regulation of sporulation is believed to have occurred during the mutation selection from the parent strain BG01-4TM. An alteration in selected sporulation regulation genes is expected to have occurred from BG01-4TM to BG01-4-8, with BG01-4-8 producing spores within 24 h, ~48 h quicker than BG01-4TM.
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Affiliation(s)
- Luke M. Bosnar
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Anya E. Shindler
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Jennifer Wood
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Craig Patch
- School of Allied Health, Human Services, and Sport, La Trobe University, Melbourne, Victoria 3086, Australia
- Vernx Pty Ltd, Level 17, 40 City Road, Southbank, Victoria 3066, Australia
| | - Ashley E. Franks
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
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Auria E, Hunault L, England P, Monot M, Pipoli Da Fonseca J, Matondo M, Duchateau M, Tremblay YDN, Dupuy B. The cell wall lipoprotein CD1687 acts as a DNA binding protein during deoxycholate-induced biofilm formation in Clostridioides difficile. NPJ Biofilms Microbiomes 2023; 9:24. [PMID: 37169797 PMCID: PMC10175255 DOI: 10.1038/s41522-023-00393-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 04/27/2023] [Indexed: 05/13/2023] Open
Abstract
The ability of bacterial pathogens to establish recurrent and persistent infections is frequently associated with their ability to form biofilms. Clostridioides difficile infections have a high rate of recurrence and relapses and it is hypothesized that biofilms are involved in its pathogenicity and persistence. Biofilm formation by C. difficile is still poorly understood. It has been shown that specific molecules such as deoxycholate (DCA) or metronidazole induce biofilm formation, but the mechanisms involved remain elusive. In this study, we describe the role of the C. difficile lipoprotein CD1687 during DCA-induced biofilm formation. We showed that the expression of CD1687, which is part of an operon within the CD1685-CD1689 gene cluster, is controlled by multiple transcription starting sites and some are induced in response to DCA. Only CD1687 is required for biofilm formation and the overexpression of CD1687 is sufficient to induce biofilm formation. Using RNAseq analysis, we showed that CD1687 affects the expression of transporters and metabolic pathways and we identified several potential binding partners by pull-down assay, including transport-associated extracellular proteins. We then demonstrated that CD1687 is surface exposed in C. difficile, and that this localization is required for DCA-induced biofilm formation. Given this localization and the fact that C. difficile forms eDNA-rich biofilms, we confirmed that CD1687 binds DNA in a non-specific manner. We thus hypothesize that CD1687 is a component of the downstream response to DCA leading to biofilm formation by promoting interaction between the cells and the biofilm matrix by binding eDNA.
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Affiliation(s)
- Emile Auria
- Institut Pasteur, Université Paris-Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015, Paris, France
| | - Lise Hunault
- Institut Pasteur, Université Paris-Cité, INSERM UMR1222, Unit of Antibodies in Therapy and Pathology, Paris, France
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), F-75013, Paris, France
| | - Patrick England
- Plateforme de Biophysique Moléculaire, Institut Pasteur, CNRS UMR3528, Paris, France
| | - Marc Monot
- Plateforme Technologique Biomics, Institut Pasteur, Paris, France
| | | | | | | | - Yannick D N Tremblay
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Bruno Dupuy
- Institut Pasteur, Université Paris-Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015, Paris, France.
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14
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Fuchs M, Lamm-Schmidt V, Lenče T, Sulzer J, Bublitz A, Wackenreuter J, Gerovac M, Strowig T, Faber F. A network of small RNAs regulates sporulation initiation in Clostridioides difficile. EMBO J 2023:e112858. [PMID: 37140366 DOI: 10.15252/embj.2022112858] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 05/05/2023] Open
Abstract
The obligate anaerobic, enteric pathogen Clostridioides difficile persists in the intestinal tract by forming antibiotic-resistant endospores that contribute to relapsing and recurrent infections. Despite the importance of sporulation for C. difficile pathogenesis, environmental cues and molecular mechanisms that regulate sporulation initiation remain ill-defined. Here, by using RIL-seq to globally capture the Hfq-dependent RNA-RNA interactome, we discovered a network of small RNAs that bind to mRNAs encoding sporulation-related genes. We show that two of these small RNAs, SpoX and SpoY, regulate translation of the master regulator of sporulation, Spo0A, in an opposing manner, which ultimately leads to altered sporulation rates. Infection of antibiotic-treated mice with SpoX and SpoY deletion mutants revealed a global effect on gut colonization and intestinal sporulation. Our work uncovers an elaborate RNA-RNA interactome controlling the physiology and virulence of C. difficile and identifies a complex post-transcriptional layer in the regulation of spore formation in this important human pathogen.
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Affiliation(s)
- Manuela Fuchs
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Vanessa Lamm-Schmidt
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Tina Lenče
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Johannes Sulzer
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Arne Bublitz
- Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Janet Wackenreuter
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
| | - Milan Gerovac
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Till Strowig
- Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
- German Center for Infection Research (DZIF), Hannover-Braunschweig, Germany
| | - Franziska Faber
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
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15
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Zeng J, Wang H, Dong M, Tian GB. Clostridioides difficile spore: coat assembly and formation. Emerg Microbes Infect 2022; 11:2340-2349. [PMID: 36032037 PMCID: PMC9542656 DOI: 10.1080/22221751.2022.2119168] [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] [Indexed: 11/07/2022]
Abstract
Clostridioides difficile (C. difficile) is a Gram-positive, spore-forming, toxin-producing, obligate anaerobic bacterium. C. difficile infection (CDI) is the leading cause of healthcare-associated infective diarrhoea. The infection is mediated by the spore, a metabolically inactive form of C. difficile. The spore coat acts as a physical barrier to defend against chemical insults from hosts and natural environments. The composition of spore coat has already been revealed; therefore, the interactive networks of spore coat proteins and the dynamic process of coat assembly are the keys to design strategies to control and cure CDI. This review gives a brief discussion of the signal processing and transcriptional regulation of C. difficile sporulation initiation. Following the discussion, the spore formation is also introduced. Finally, this review mainly focuses on the spore coat assembly, a poorly understood process in C. difficile, and important proteins that have been studied.
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Affiliation(s)
- Ji Zeng
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Hao Wang
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Min Dong
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
- Department of Urology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Guo-Bao Tian
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangdong 510080, China
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
- Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
- School of Medicine, Xizang Minzu University, Xianyang, Shaanxi 712082, China
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16
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Anwar F, Roxas BAP, Shehab KW, Ampel N, Viswanathan VK, Vedantam G. Low-Toxin Clostridioides difficile RT027 Strains Exhibit Robust Virulence. Emerg Microbes Infect 2022; 11:1982-1993. [PMID: 35880487 PMCID: PMC9361768 DOI: 10.1080/22221751.2022.2105260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Clostridioides difficile is a leading cause of healthcare-associated infections worldwide. Currently, there is a lack of consensus for an optimal diagnostic method for C. difficile infection (CDI). Multi-step diagnostic algorithms use enzyme immunosorbent analysis (EIA)-based detection of C. difficile toxins TcdA/TcdB in stool, premised on the rationale that EIA toxin-negative (Tox−) patients have less severe disease and shorter diarrhoea duration. The aim of this study was to characterize toxigenic (i.e. tcdA/tcdB-positive) C. difficile strains isolated from diarrheic patient stool with an EIA Tox− (i.e. “discrepant”) CDI diagnostic test result. Recovered strains were DNA fingerprinted (ribotyped), subjected to multiple toxin, genome and proteome evaluations, and assessed for virulence. Overall, of 1243 C. difficile-positive patient stool specimens from Southern Arizona hospitals, 31% were discrepant. For RT027 (the most prevalent ribotype)-containing specimens, 34% were discrepant; the corresponding RT027 isolates were cytotoxic to cultured fibroblasts, but their total toxin levels were comparable to, or lower than, the historic low-toxin-producing C. difficile strain CD630. Nevertheless, these low-toxin RT027 strains (LT-027) exhibited similar lethality to a clade-matched high-toxin RT027 strain in Golden Syrian hamsters, and heightened colonization and persistence in mice. Genomics and proteomics analyses of LT-027 strains identified unique genes and altered protein abundances, respectively, relative to high-toxin RT027 strains. Collectively, our data highlight the robust virulence of LT-027 C. difficile, provide a strong argument for reconsidering the clinical significance of a Tox− EIA result, and underscore the potential limitations of current diagnostic protocols.
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Affiliation(s)
- Farhan Anwar
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ, USA
| | - Bryan Angelo P Roxas
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ, USA
| | - Kareem W Shehab
- Department of Pediatrics, The University of Arizona College of Medicine, Tucson, AZ, USA
| | | | - V K Viswanathan
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ, USA.,Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ, USA.,BIO5 Institute for Collaborative Research, The University of Arizona, Tucson, AZ, USA
| | - Gayatri Vedantam
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ, USA.,Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ, USA.,BIO5 Institute for Collaborative Research, The University of Arizona, Tucson, AZ, USA.,Southern Arizona VA Healthcare System, Tucson, AZ, USA
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Development of a Dual-Fluorescent-Reporter System in Clostridioides difficile Reveals a Division of Labor between Virulence and Transmission Gene Expression. mSphere 2022; 7:e0013222. [PMID: 35638354 PMCID: PMC9241537 DOI: 10.1128/msphere.00132-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The bacterial pathogen Clostridioides difficile causes gastroenteritis by producing toxins and transmits disease by making resistant spores. Toxin and spore production are energy-expensive processes that are regulated by multiple transcription factors in response to many environmental inputs. While toxin and sporulation genes are both induced in only a subset of C. difficile cells, the relationship between these two subpopulations remains unclear. To address whether C. difficile coordinates the generation of these subpopulations, we developed a dual-transcriptional-reporter system that allows toxin and sporulation gene expression to be simultaneously visualized at the single-cell level using chromosomally encoded mScarlet and mNeonGreen fluorescent transcriptional reporters. We then adapted an automated image analysis pipeline to quantify toxin and sporulation gene expression in thousands of individual cells under different medium conditions and in different genetic backgrounds. These analyses revealed that toxin and sporulation gene expression rarely overlap during growth on agar plates, whereas broth culture increases this overlap. Our results suggest that certain growth conditions promote a “division of labor” between transmission and virulence gene expression, highlighting how environmental inputs influence these subpopulations. Our data further suggest that the RstA transcriptional regulator skews the population to activate sporulation genes rather than toxin genes. Given that recent work has revealed population-wide heterogeneity for numerous cellular processes in C. difficile, we anticipate that our dual-reporter system will be broadly useful for determining the overlap between these subpopulations. IMPORTANCEClostridioides difficile is an important nosocomial pathogen that causes severe diarrhea by producing toxins and transmits disease by producing spores. While both processes are crucial for C. difficile disease, only a subset of cells express toxins and/or undergo sporulation. Whether C. difficile coordinates the subset of cells inducing these energy-expensive processes remains unknown. To address this question, we developed a dual-fluorescent-reporter system coupled with an automated image analysis pipeline to rapidly compare the expression of two genes of interest across thousands of cells. Using this system, we discovered that certain growth conditions, particularly growth on agar plates, induce a “division of labor” between toxin and sporulation gene expression. Since C. difficile exhibits phenotypic heterogeneity for numerous vital cellular processes, this novel dual-reporter system will enable future studies aimed at understanding how C. difficile coordinates various subpopulations throughout its infectious disease cycle.
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18
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Trzilova D, Warren MAH, Gadda NC, Williams CL, Tamayo R. Flagellum and toxin phase variation impacts intestinal colonization and disease development in a mouse model of Clostridioides difficile infection. Gut Microbes 2022; 14:2038854. [PMID: 35192433 PMCID: PMC8890394 DOI: 10.1080/19490976.2022.2038854] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Clostridioides difficile is a major nosocomial pathogen that can cause severe, toxin-mediated diarrhea and pseudomembranous colitis. Recent work has shown that C. difficile exhibits heterogeneity in swimming motility and toxin production in vitro through phase variation by site-specific DNA recombination. The recombinase RecV reversibly inverts the flagellar switch sequence upstream of the flgB operon, leading to the ON/OFF expression of flagellum and toxin genes. How this phenomenon impacts C. difficile virulence in vivo remains unknown. We identified mutations in the right inverted repeat that reduced or prevented flagellar switch inversion by RecV. We introduced these mutations into C. difficile R20291 to create strains with the flagellar switch "locked" in either the ON or OFF orientation. These mutants exhibited a loss of flagellum and toxin phase variation during growth in vitro, yielding precisely modified mutants suitable for assessing virulence in vivo. In a hamster model of acute C. difficile infection, the phase-locked ON mutant caused greater toxin accumulation than the phase-locked OFF mutant but did not differ significantly in the ability to cause acute disease symptoms. In contrast, in a mouse model, preventing flagellum and toxin phase variation affected the ability of C. difficile to colonize the intestinal tract and to elicit weight loss, which is attributable to differences in toxin production during infection. These results show that the ability of C. difficile to phase vary flagella and toxins influences colonization and disease development and suggest that the phenotypic variants generated by flagellar switch inversion have distinct capacities for causing disease.
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Affiliation(s)
- Dominika Trzilova
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Mercedes A. H. Warren
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Nicole C. Gadda
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Caitlin L. Williams
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Rita Tamayo
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,CONTACT Rita Tamayo 125 Mason Farm Rd, CB #7290, Chapel Hill, NC27599-7290
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Abstract
The ability of the anaerobic gastrointestinal pathogen Clostridioides difficile to survive outside the host relies on the formation of dormant endospores. Spore formation is contingent on the activation of a conserved transcription factor, Spo0A, by phosphorylation. Multiple kinases and phosphatases regulate Spo0A activity in other spore-forming organisms; however, these factors are not well conserved in C. difficile. Previously, we discovered that deletion of a predicted histidine kinase, CD1492, increases sporulation, indicating that CD1492 inhibits C. difficile spore formation. In this study, we investigate the functions of additional predicted orphan histidine kinases CD2492, CD1579, and CD1949, which are hypothesized to regulate Spo0A phosphorylation. Disruption of CD2492 also increased sporulation frequency, similarly to the CD1492 mutant and in contrast to a previous study. A CD1492 CD2492 mutant phenocopied the sporulation and gene expression patterns of the single mutants, suggesting that these proteins function in the same genetic pathway to repress sporulation. Deletion of CD1579 variably increased sporulation frequency; however, knockdown of CD1949 expression did not influence sporulation. We provide evidence that CD1492, CD2492, and CD1579 function as phosphatases, as mutation of the conserved histidine residue for phosphate transfer abolished CD2492 function, and expression of the CD1492 or CD2492 histidine site-directed mutants or the wild-type CD1579 allele in a parent strain resulted in a dominant-negative hypersporulation phenotype. Altogether, at least three predicted histidine kinases, CD1492, CD2492, and CD1579 (herein, PtpA, PtpB and PtpC), repress C. difficile sporulation initiation by regulating activity of Spo0A. IMPORTANCE The formation of inactive spores is critical for the long-term survival of the gastrointestinal pathogen Clostridioides difficile. The onset of sporulation is controlled by the master regulator of sporulation, Spo0A, which is activated by phosphorylation. Multiple kinases and phosphatases control Spo0A phosphorylation; however, this regulatory pathway is not defined in C. difficile. We show that two predicted histidine kinase proteins, CD1492 (PtpA) and CD2492 (PtpB), function in the same regulatory pathway to repress sporulation by preventing Spo0A phosphorylation. We show that another predicted histidine kinase protein, CD1579 (PtpC), also represses sporulation and present evidence that a fourth predicted histidine kinase protein, CD1949, does not impact sporulation. These results support the idea that C. difficile inhibits sporulation initiation through multiple phosphatases.
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20
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Regulation of Clostridioides difficile toxin production. Curr Opin Microbiol 2022; 65:95-100. [PMID: 34781095 PMCID: PMC8792210 DOI: 10.1016/j.mib.2021.10.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/19/2021] [Accepted: 10/25/2021] [Indexed: 02/03/2023]
Abstract
Clostridioides difficile produces toxins TcdA and TcdB during infection. Since the severity of the illness is directly correlated with the level of toxins produced, researchers have long been interested in the regulation mechanisms of toxin production. The advent of new genetics and mutagenesis technologies in C. difficile has allowed a slew of new investigations in the last decade, which considerably improved our understanding of this crucial regulatory network. The current body of work shows that the toxin regulatory network overlaps with the regulatory networks of sporulation, motility, and key metabolic pathways. This implies that toxin production is a complicated process initiated by bacteria in response to numerous host factors during infection. We summarize the existing knowledge about the toxin gene regulatory network here.
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21
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Oliveira Paiva AM, Friggen AH, Douwes R, Wittekoek B, Smits WK. Practical observations on the use of fluorescent reporter systems in Clostridioides difficile. Antonie van Leeuwenhoek 2022; 115:297-323. [PMID: 35039954 DOI: 10.1007/s10482-021-01691-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/19/2021] [Indexed: 12/18/2022]
Abstract
Fluorescence microscopy is a valuable tool to study a broad variety of bacterial cell components and dynamics thereof. For Clostridioides difficile, the fluorescent proteins CFPopt, mCherryOpt and phiLOV2.1, and the self-labelling tags SNAPCd and HaloTag, hereafter collectively referred as fluorescent systems, have been described to explore different cellular pathways. In this study, we sought to characterize previously used fluorescent systems in C. difficile cells. We performed single cell analyses using fluorescence microscopy of exponentially growing C. difficile cells harbouring different fluorescent systems, either expressing these separately in the cytosol or fused to the C-terminus of HupA, under defined conditions. We show that the intrinsic fluorescence of C. difficile cells increases during growth, independent of sigB or spo0A. However, when C. difficile cells are exposed to environmental oxygen autofluorescence is enhanced. Cytosolic overexpression of the different fluorescent systems alone, using the same expression signals, showed heterogeneous expression of the fluorescent systems. High levels of mCherryOpt were toxic for C. difficile cells limiting the applicability of this fluorophore as a transcriptional reporter. When fused to HupA, a C. difficile histone-like protein, the fluorescent systems behaved similarly and did not affect the HupA overproduction phenotype. The present study compares several commonly used fluorescent systems for application as transcriptional or translational reporters in microscopy and summarizes the limitations and key challenges for live-cell imaging of C. difficile. Due to independence of molecular oxygen and fluorescent signal, SNAPCd appears the most suitable candidate for live-cell imaging in C. difficile to date.
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Affiliation(s)
- Ana M Oliveira Paiva
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands.,Center for Microbial Cell Biology, Leiden, The Netherlands.,Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198, Gif-sur-Yvette, France
| | - Annemieke H Friggen
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands.,Center for Microbial Cell Biology, Leiden, The Netherlands
| | - Roxanne Douwes
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - Bert Wittekoek
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands. .,Center for Microbial Cell Biology, Leiden, The Netherlands.
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22
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Naskulwar K, Peña-Castillo L. sRNARFTarget: a fast machine-learning-based approach for transcriptome-wide sRNA target prediction. RNA Biol 2021; 19:44-54. [PMID: 34965197 PMCID: PMC8794260 DOI: 10.1080/15476286.2021.2012058] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Bacterial small regulatory RNAs (sRNAs) are key regulators of gene expression in many processes related to adaptive responses. A multitude of sRNAs have been identified in many bacterial species; however, their function has yet to be elucidated. A key step to understand sRNAs function is to identify the mRNAs these sRNAs bind to. There are several computational methods for sRNA target prediction, and the most accurate one is CopraRNA which is based on comparative-genomics. However, species-specific sRNAs are quite common and CopraRNA cannot be used for these sRNAs. The most commonly used transcriptome-wide sRNA target prediction method and second-most-accurate method is IntaRNA. However, IntaRNA can take hours to run on a bacterial transcriptome. Here we present sRNARFTarget, a machine-learning-based method for transcriptome-wide sRNA target prediction applicable to any sRNA. We comparatively assessed the performance of sRNARFTarget, CopraRNA and IntaRNA in three bacterial species. Our results show that sRNARFTarget outperforms IntaRNA in terms of accuracy, ranking of true interacting pairs, and running time. However, CopraRNA substantially outperforms the other two programsin terms of accuracy. Thus, we suggest using CopraRNA when homolog sequences of the sRNA are available, and sRNARFTarget for transcriptome-wide prediction or for species-specific sRNAs. sRNARFTarget is available at https://github.com/BioinformaticsLabAtMUN/sRNARFTarget.
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Affiliation(s)
- Kratika Naskulwar
- Department of Computer Science, Memorial University of Newfoundland, St. John's, Canada
| | - Lourdes Peña-Castillo
- Department of Computer Science, Memorial University of Newfoundland, St. John's, Canada.,Department of Biology, Memorial University of Newfoundland, St. John's, Canada
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23
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Lee CD, Rizvi A, Edwards AN, DiCandia MA, Vargas Cuebas GG, Monteiro MP, McBride SM. Genetic mechanisms governing sporulation initiation in Clostridioides difficile. Curr Opin Microbiol 2021; 66:32-38. [PMID: 34933206 DOI: 10.1016/j.mib.2021.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/03/2021] [Accepted: 12/05/2021] [Indexed: 12/15/2022]
Abstract
As an anaerobe, Clostridioides difficile relies on the formation of a dormant spore for survival outside of the mammalian host's gastrointestinal tract. The spore is recalcitrant to desiccation, numerous disinfectants, UV light, and antibiotics, permitting long-term survival against environmental insults and efficient transmission from host to host. Although the morphological stages of spore formation are similar between C. difficile and other well-studied endospore-forming bacteria, the C. difficile genome does not appear to encode many of the known, conserved regulatory factors that are necessary to initiate sporulation in other spore-forming bacteria. The absence of early sporulation-specific orthologs suggests that C. difficile has evolved to control sporulation initiation in response to its unique and specific ecological niche and environmental cues within the host. Here, we review our current understanding and highlight the recent discoveries that have begun to unravel the regulatory pathways and molecular mechanisms by which C. difficile induces spore formation.
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Affiliation(s)
- Cheyenne D Lee
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, GA, USA
| | - Arshad Rizvi
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, GA, USA
| | - Adrianne N Edwards
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, GA, USA
| | - Michael A DiCandia
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, GA, USA
| | - Germán G Vargas Cuebas
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, GA, USA
| | - Marcos P Monteiro
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, GA, USA
| | - Shonna M McBride
- Department of Microbiology and Immunology, Emory University School of Medicine, Emory Antibiotic Resistance Center, Atlanta, GA, USA.
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24
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Metabolic adaption to extracellular pyruvate triggers biofilm formation in Clostridioides difficile. THE ISME JOURNAL 2021; 15:3623-3635. [PMID: 34155333 PMCID: PMC8630010 DOI: 10.1038/s41396-021-01042-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 02/06/2023]
Abstract
Clostridioides difficile infections are associated with gut microbiome dysbiosis and are the leading cause of hospital-acquired diarrhoea. The infectious process is strongly influenced by the microbiota and successful infection relies on the absence of specific microbiota-produced metabolites. Deoxycholate and short-chain fatty acids are microbiota-produced metabolites that limit the growth of C. difficile and protect the host against this infection. In a previous study, we showed that deoxycholate causes C. difficile to form strongly adherent biofilms after 48 h. Here, our objectives were to identify and characterize key molecules and events required for biofilm formation in the presence of deoxycholate. We applied time-course transcriptomics and genetics to identify sigma factors, metabolic processes and type IV pili that drive biofilm formation. These analyses revealed that extracellular pyruvate induces biofilm formation in the presence of deoxycholate. In the absence of deoxycholate, pyruvate supplementation was sufficient to induce biofilm formation in a process that was dependent on pyruvate uptake by the membrane protein CstA. In the context of the human gut, microbiota-generated pyruvate is a metabolite that limits pathogen colonization. Taken together our results suggest that pyruvate-induced biofilm formation might act as a key process driving C. difficile persistence in the gut.
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25
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Arrieta-Ortiz ML, Immanuel SRC, Turkarslan S, Wu WJ, Girinathan BP, Worley JN, DiBenedetto N, Soutourina O, Peltier J, Dupuy B, Bry L, Baliga NS. Predictive regulatory and metabolic network models for systems analysis of Clostridioides difficile. Cell Host Microbe 2021; 29:1709-1723.e5. [PMID: 34637780 PMCID: PMC8595754 DOI: 10.1016/j.chom.2021.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/29/2021] [Accepted: 09/16/2021] [Indexed: 12/15/2022]
Abstract
We present predictive models for comprehensive systems analysis of Clostridioides difficile, the etiology of pseudomembranous colitis. By leveraging 151 published transcriptomes, we generated an EGRIN model that organizes 90% of C. difficile genes into a transcriptional regulatory network of 297 co-regulated modules, implicating genes in sporulation, carbohydrate transport, and metabolism. By advancing a metabolic model through addition and curation of metabolic reactions including nutrient uptake, we discovered 14 amino acids, diverse carbohydrates, and 10 metabolic genes as essential for C. difficile growth in the intestinal environment. Finally, we developed a PRIME model to uncover how EGRIN-inferred combinatorial gene regulation by transcription factors, such as CcpA and CodY, modulates essential metabolic processes to enable C. difficile growth relative to commensal colonization. The C. difficile interactive web portal provides access to these model resources to support collaborative systems-level studies of context-specific virulence mechanisms in C. difficile.
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Affiliation(s)
| | | | | | - Wei-Ju Wu
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Brintha P Girinathan
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jay N Worley
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Nicholas DiBenedetto
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-yvette 91198, France
| | - Johann Peltier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-yvette 91198, France
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries anaérobies, Institut Pasteur, Université de Paris, UMR CNRS 2001, Paris 75015, France
| | - Lynn Bry
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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26
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Dhungel BA, Govind R. Phase-variable expression of pdcB, a phosphodiesterase, influences sporulation in Clostridioides difficile. Mol Microbiol 2021; 116:1347-1360. [PMID: 34606654 DOI: 10.1111/mmi.14828] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 02/07/2023]
Abstract
Clostridioides difficile is the causative agent of antibiotic-associated diarrhea and is the leading cause of nosocomial infection in developed countries. An increasing number of C. difficile infections are attributed to epidemic strains that produce more toxins and spores. C. difficile spores are the major factor for the transmission and persistence of the organism. Previous studies have identified global regulators that influence sporulation in C. difficile. This study discovers that PdcB, a phosphodiesterase, enhances sporulation in C. difficile strain UK1. Through genetic and biochemical assays, we show that phase-variable expression of pdcB results in hypo- and hyper-sporulation phenotypes. In the "ON" orientation, the identified promotor is in the right orientation to drive the expression of pdcB. Production of the PdcB phosphodiesterase reduces the intracellular cyclic-di-GMP (c-di-GMP) concentration, resulting in a hyper-sporulation phenotype. Loss of PdcB due to the pdcB promoter being in the OFF orientation or mutation of pdcB results in increased c-di-GMP levels and a hypo-sporulation phenotype. Additionally, we demonstrate that CodY binds to the upstream region of pdcB. DNA inversion reorients the CodY binding site so that in the OFF orientation, CodY binds a site that is upstream of the pdcB promoter and can further repress gene expression.
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Affiliation(s)
| | - Revathi Govind
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
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27
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Maan H, Gilhar O, Porat Z, Kolodkin-Gal I. Bacillus subtilis Colonization of Arabidopsis thaliana Roots Induces Multiple Biosynthetic Clusters for Antibiotic Production. Front Cell Infect Microbiol 2021; 11:722778. [PMID: 34557426 PMCID: PMC8454505 DOI: 10.3389/fcimb.2021.722778] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/16/2021] [Indexed: 12/01/2022] Open
Abstract
Beneficial and probiotic bacteria play an important role in conferring immunity of their hosts to a wide range of bacterial, viral, and fungal diseases. Bacillus subtilis is a Gram-positive bacterium that protects the plant from various pathogens due to its capacity to produce an extensive repertoire of antibiotics. At the same time, the plant microbiome is a highly competitive niche, with multiple microbial species competing for space and resources, a competition that can be determined by the antagonistic potential of each microbiome member. Therefore, regulating antibiotic production in the rhizosphere is of great importance for the elimination of pathogens and establishing beneficial host-associated communities. In this work, we used B. subtilis as a model to investigate the role of plant colonization in antibiotic production. Flow cytometry and imaging flow cytometry (IFC) analysis supported the notion that Arabidopsis thaliana specifically induced the transcription of the biosynthetic clusters for the non-ribosomal peptides surfactin, bacilysin, plipastatin, and the polyketide bacillaene. IFC was more robust in quantifying the inducing effects of A. thaliana, considering the overall heterogeneity of the population. Our results highlight IFC as a useful tool to study the effect of association with a plant host on bacterial gene expression. Furthermore, the common regulation of multiple biosynthetic clusters for antibiotic production by the plant can be translated to improve the performance and competitiveness of beneficial members of the plant microbiome.
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Affiliation(s)
- Harsh Maan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Omri Gilhar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ziv Porat
- Flow Cytometry Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Ilana Kolodkin-Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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28
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Maikova A, Boudry P, Shiriaeva A, Vasileva A, Boutserin A, Medvedeva S, Semenova E, Severinov K, Soutourina O. Protospacer-Adjacent Motif Specificity during Clostridioides difficile Type I-B CRISPR-Cas Interference and Adaptation. mBio 2021; 12:e0213621. [PMID: 34425703 PMCID: PMC8406132 DOI: 10.1128/mbio.02136-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 07/26/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems provide prokaryotes with efficient protection against foreign nucleic acid invaders. We have recently demonstrated the defensive interference function of a CRISPR-Cas system from Clostridioides (Clostridium) difficile, a major human enteropathogen, and showed that it could be harnessed for efficient genome editing in this bacterium. However, molecular details are still missing on CRISPR-Cas function for adaptation and sequence requirements for both interference and new spacer acquisition in this pathogen. Despite accumulating knowledge on the individual CRISPR-Cas systems in various prokaryotes, no data are available on the adaptation process in bacterial type I-B CRISPR-Cas systems. Here, we report the first experimental evidence that the C. difficile type I-B CRISPR-Cas system acquires new spacers upon overexpression of its adaptation module. The majority of new spacers are derived from a plasmid expressing Cas proteins required for adaptation or from regions of the C. difficile genome where generation of free DNA termini is expected. Results from protospacer-adjacent motif (PAM) library experiments and plasmid conjugation efficiency assays indicate that C. difficile CRISPR-Cas requires the YCN consensus PAM for efficient interference. We revealed a functional link between the adaptation and interference machineries, since newly adapted spacers are derived from sequences associated with a CCN PAM, which fits the interference consensus. The definition of functional PAMs and establishment of relative activity levels of each of the multiple C. difficile CRISPR arrays in present study are necessary for further CRISPR-based biotechnological and medical applications involving this organism. IMPORTANCE CRISPR-Cas systems provide prokaryotes with adaptive immunity for defense against foreign nucleic acid invaders, such as viruses or phages and plasmids. The CRISPR-Cas systems are highly diverse, and detailed studies of individual CRISPR-Cas subtypes are important for our understanding of various aspects of microbial adaptation strategies and for the potential applications. The significance of our work is in providing the first experimental evidence for type I-B CRISPR-Cas system adaptation in the emerging human enteropathogen Clostridioides difficile. This bacterium needs to survive in phage-rich gut communities, and its active CRISPR-Cas system might provide efficient antiphage defense by acquiring new spacers that constitute memory for further invader elimination. Our study also reveals a functional link between the adaptation and interference CRISPR machineries. The definition of all possible functional trinucleotide motifs upstream protospacers within foreign nucleic acid sequences is important for CRISPR-based genome editing in this pathogen and for developing new drugs against C. difficile infections.
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Affiliation(s)
- Anna Maikova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia
| | - Pierre Boudry
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Anna Shiriaeva
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia
| | - Aleksandra Vasileva
- Institute of Gene Biology, Centre for Precision Genome Editing and Genetic Technologies for Biomedicine, Russian Academy of Sciences, Moscow, Russia
| | - Anaïs Boutserin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Sofia Medvedeva
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Ekaterina Semenova
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Konstantin Severinov
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Institut Universitaire de France (IUF), Paris, France
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29
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An RNA-centric global view of Clostridioides difficile reveals broad activity of Hfq in a clinically important gram-positive bacterium. Proc Natl Acad Sci U S A 2021; 118:2103579118. [PMID: 34131082 PMCID: PMC8237595 DOI: 10.1073/pnas.2103579118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The gram-positive human pathogen Clostridioides difficile has emerged as the leading cause of antibiotic-associated diarrhea. However, little is known about the bacterium's transcriptome architecture and mechanisms of posttranscriptional control. Here, we have applied transcription start site and termination mapping to generate a single-nucleotide-resolution RNA map of C. difficile 5' and 3' untranslated regions, operon structures, and noncoding regulators, including 42 sRNAs. Our results indicate functionality of many conserved riboswitches and predict cis-regulatory RNA elements upstream of multidrug resistance (MDR)-type ATP-binding cassette (ABC) transporters and transcriptional regulators. Despite growing evidence for a role of Hfq in RNA-based gene regulation in C. difficile, the functions of Hfq-based posttranscriptional regulatory networks in gram-positive pathogens remain controversial. Using Hfq immunoprecipitation followed by sequencing of bound RNA species (RIP-seq), we identify a large cohort of transcripts bound by Hfq and show that absence of Hfq affects transcript stabilities and steady-state levels. We demonstrate sRNA expression during intestinal colonization by C. difficile and identify infection-related signals impacting its expression. As a proof of concept, we show that the utilization of the abundant intestinal metabolite ethanolamine is regulated by the Hfq-dependent sRNA CDIF630nc_085. Overall, our study lays the foundation for understanding clostridial riboregulation with implications for the infection process and provides evidence for a global role of Hfq in posttranscriptional regulation in a gram-positive bacterium.
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Brauer M, Lassek C, Hinze C, Hoyer J, Becher D, Jahn D, Sievers S, Riedel K. What's a Biofilm?-How the Choice of the Biofilm Model Impacts the Protein Inventory of Clostridioides difficile. Front Microbiol 2021; 12:682111. [PMID: 34177868 PMCID: PMC8225356 DOI: 10.3389/fmicb.2021.682111] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/12/2021] [Indexed: 12/18/2022] Open
Abstract
The anaerobic pathogen Clostridioides difficile is perfectly equipped to survive and persist inside the mammalian intestine. When facing unfavorable conditions C. difficile is able to form highly resistant endospores. Likewise, biofilms are currently discussed as form of persistence. Here a comprehensive proteomics approach was applied to investigate the molecular processes of C. difficile strain 630Δerm underlying biofilm formation. The comparison of the proteome from two different forms of biofilm-like growth, namely aggregate biofilms and colonies on agar plates, revealed major differences in the formation of cell surface proteins, as well as enzymes of its energy and stress metabolism. For instance, while the obtained data suggest that aggregate biofilm cells express both flagella, type IV pili and enzymes required for biosynthesis of cell-surface polysaccharides, the S-layer protein SlpA and most cell wall proteins (CWPs) encoded adjacent to SlpA were detected in significantly lower amounts in aggregate biofilm cells than in colony biofilms. Moreover, the obtained data suggested that aggregate biofilm cells are rather actively growing cells while colony biofilm cells most likely severely suffer from a lack of reductive equivalents what requires induction of the Wood-Ljungdahl pathway and C. difficile’s V-type ATPase to maintain cell homeostasis. In agreement with this, aggregate biofilm cells, in contrast to colony biofilm cells, neither induced toxin nor spore production. Finally, the data revealed that the sigma factor SigL/RpoN and its dependent regulators are noticeably induced in aggregate biofilms suggesting an important role of SigL/RpoN in aggregate biofilm formation.
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Affiliation(s)
- Madita Brauer
- Department for Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Christian Lassek
- Department for Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Christian Hinze
- Department for Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Juliane Hoyer
- Department for Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Dörte Becher
- Department for Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Dieter Jahn
- Braunschweig Integrated Centre of Systems Biology (BRICS), Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Susanne Sievers
- Department for Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Katharina Riedel
- Department for Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
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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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Ser/Thr Kinase-Dependent Phosphorylation of the Peptidoglycan Hydrolase CwlA Controls Its Export and Modulates Cell Division in Clostridioides difficile. mBio 2021; 12:mBio.00519-21. [PMID: 34006648 PMCID: PMC8262956 DOI: 10.1128/mbio.00519-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cell growth and division require a balance between synthesis and hydrolysis of the peptidoglycan (PG). Inhibition of PG synthesis or uncontrolled PG hydrolysis can be lethal for the cells, making it imperative to control peptidoglycan hydrolase (PGH) activity. The synthesis or activity of several key enzymes along the PG biosynthetic pathway is controlled by the Hanks-type serine/threonine kinases (STKs). In Gram-positive bacteria, inactivation of genes encoding STKs is associated with a range of phenotypes, including cell division defects and changes in cell wall metabolism, but only a few kinase substrates and associated mechanisms have been identified. We previously demonstrated that STK-PrkC plays an important role in cell division, cell wall metabolism, and resistance to antimicrobial compounds in the human enteropathogen Clostridioides difficile In this work, we characterized a PG hydrolase, CwlA, which belongs to the NlpC/P60 family of endopeptidases and hydrolyses cross-linked PG between daughter cells to allow cell separation. We identified CwlA as the first PrkC substrate in C. difficile We demonstrated that PrkC-dependent phosphorylation inhibits CwlA export, thereby controlling hydrolytic activity in the cell wall. High levels of CwlA at the cell surface led to cell elongation, whereas low levels caused cell separation defects. Thus, we provided evidence that the STK signaling pathway regulates PGH homeostasis to precisely control PG hydrolysis during cell division.IMPORTANCE Bacterial cells are encased in a PG exoskeleton that helps to maintain cell shape and confers physical protection. To allow bacterial growth and cell separation, PG needs to be continuously remodeled by hydrolytic enzymes that cleave PG at critical sites. How these enzymes are regulated remains poorly understood. We identify a new PG hydrolase involved in cell division, CwlA, in the enteropathogen C. difficile Lack or accumulation of CwlA at the bacterial surface is responsible for a division defect, while its accumulation in the absence of PrkC also increases susceptibility to antimicrobial compounds targeting the cell wall. CwlA is a substrate of the kinase PrkC in C. difficile PrkC-dependent phosphorylation controls the export of CwlA, modulating its levels and, consequently, its activity in the cell wall. This work provides a novel regulatory mechanism by STK in tightly controlling protein export.
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Proteomic Adaptation of Clostridioides difficile to Treatment with the Antimicrobial Peptide Nisin. Cells 2021; 10:cells10020372. [PMID: 33670309 PMCID: PMC7918085 DOI: 10.3390/cells10020372] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 01/05/2023] Open
Abstract
Clostridioides difficile is the leading cause of antibiotic-associated diarrhea but can also result in more serious, life-threatening conditions. The incidence of C. difficile infections in hospitals is increasing, both in frequency and severity, and antibiotic-resistant C. difficile strains are advancing. Against this background antimicrobial peptides (AMPs) are an interesting alternative to classic antibiotics. Information on the effects of AMPs on C. difficile will not only enhance the knowledge for possible biomedical application but may also provide insights into mechanisms of C. difficile to adapt or counteract AMPs. This study applies state-of-the-art mass spectrometry methods to quantitatively investigate the proteomic response of C. difficile 630∆erm to sublethal concentrations of the AMP nisin allowing to follow the cellular stress adaptation in a time-resolved manner. The results do not only point at a heavy reorganization of the cellular envelope but also resulted in pronounced changes in central cellular processes such as carbohydrate metabolism. Further, the number of flagella per cell was increased during the adaptation process. The potential involvement of flagella in nisin adaptation was supported by a more resistant phenotype exhibited by a non-motile but hyper-flagellated mutant.
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Abstract
Clostridioides difficile is the leading cause of nosocomial infection and is the causative agent of antibiotic-associated diarrhea. The severity of the disease is directly associated with toxin production, and spores are responsible for the transmission and persistence of the organism. Previously, we characterized sin locus regulators SinR and SinR' (we renamed it SinI), where SinR is the regulator of toxin production and sporulation. The SinI regulator acts as its antagonist. In Bacillus subtilis, Spo0A, the master regulator of sporulation, controls SinR by regulating the expression of its antagonist, sinI However, the role of Spo0A in the expression of sinR and sinI in C. difficile had not yet been reported. In this study, we tested spo0A mutants in three different C. difficile strains, R20291, UK1, and JIR8094, to understand the role of Spo0A in sin locus expression. Western blot analysis revealed that spo0A mutants had increased SinR levels. Quantitative reverse transcription-PCR (qRT-PCR) analysis of its expression further supported these data. By carrying out genetic and biochemical assays, we show that Spo0A can bind to the upstream region of this locus to regulates its expression. This study provides vital information that Spo0A regulates the sin locus, which controls critical pathogenic traits such as sporulation, toxin production, and motility in C. difficile IMPORTANCE Clostridioides difficile is the leading cause of antibiotic-associated diarrheal disease in the United States. During infection, C. difficile spores germinate, and the vegetative bacterial cells produce toxins that damage host tissue. In C. difficile, the sin locus is known to regulate both sporulation and toxin production. In this study, we show that Spo0A, the master regulator of sporulation, controls sin locus expression. Results from our study suggest that Spo0A directly regulates the expression of this locus by binding to its upstream DNA region. This observation adds new detail to the gene regulatory network that connects sporulation and toxin production in this pathogen.
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Clostridioides difficile para-Cresol Production Is Induced by the Precursor para-Hydroxyphenylacetate. J Bacteriol 2020; 202:JB.00282-20. [PMID: 32631945 PMCID: PMC7925072 DOI: 10.1128/jb.00282-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 06/24/2020] [Indexed: 12/12/2022] Open
Abstract
Clostridioides difficile is an etiological agent for antibiotic-associated diarrheal disease. C. difficile produces a phenolic compound, para-cresol, which selectively targets gammaproteobacteria in the gut, facilitating dysbiosis. C. difficile decarboxylates para-hydroxyphenylacetate (p-HPA) to produce p-cresol by the action of the HpdBCA decarboxylase encoded by the hpdBCA operon. Here, we investigate regulation of the hpdBCA operon and directly compare three independent reporter systems; SNAP-tag, glucuronidase gusA, and alkaline phosphatase phoZ reporters to detect basal and inducible expression. We show that expression of hpdBCA is upregulated in response to elevated p-HPA. In silico analysis identified three putative promoters upstream of hpdBCA operon-P1, P2, and Pσ54; only the P1 promoter was responsible for both basal and p-HPA-inducible expression of hpdBCA We demonstrated that turnover of tyrosine, a precursor for p-HPA, is insufficient to induce expression of the hpdBCA operon above basal levels because it is inefficiently converted to p-HPA in minimal media. We show that induction of the hpdBCA operon in response to p-HPA occurs in a dose-dependent manner. We also identified an inverted palindromic repeat (AAAAAG-N13-CTTTTT) upstream of the hpdBCA start codon (ATG) that is essential for inducing transcription of the hpdBCA operon in response to p-HPA, which drives the production of p-cresol. This provides insights into the regulatory control of p-cresol production, which affords a competitive advantage for C. difficile over other intestinal bacteria, promoting dysbiosis.IMPORTANCE Clostridioides difficile infection results from antibiotic-associated dysbiosis. para-Cresol, a phenolic compound produced by C. difficile, selectively targets gammaproteobacteria in the gut, facilitating dysbiosis. Here, we demonstrate that expression of the hpdBCA operon, encoding the HpdBCA decarboxylase which converts p-HPA to p-cresol, is upregulated in response to elevated exogenous p-HPA, with induction occurring between >0.1 and ≤0.25 mg/ml. We determined a single promoter and an inverted palindromic repeat responsible for basal and p-HPA-inducible hpdBCA expression. We identified turnover of tyrosine, a p-HPA precursor, does not induce hpdBCA expression above basal level, indicating that exogenous p-HPA was required for p-cresol production. Identifying regulatory controls of p-cresol production will provide novel therapeutic targets to prevent p-cresol production, reducing C. difficile's competitive advantage.
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Soutourina O, Dubois T, Monot M, Shelyakin PV, Saujet L, Boudry P, Gelfand MS, Dupuy B, Martin-Verstraete I. Genome-Wide Transcription Start Site Mapping and Promoter Assignments to a Sigma Factor in the Human Enteropathogen Clostridioides difficile. Front Microbiol 2020; 11:1939. [PMID: 32903654 PMCID: PMC7438776 DOI: 10.3389/fmicb.2020.01939] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/23/2020] [Indexed: 12/12/2022] Open
Abstract
The emerging human enteropathogen Clostridioides difficile is the main cause of diarrhea associated with antibiotherapy. Regulatory pathways underlying the adaptive responses remain understudied and the global view of C. difficile promoter structure is still missing. In the genome of C. difficile 630, 22 genes encoding sigma factors are present suggesting a complex pattern of transcription in this bacterium. We present here the first transcriptional map of the C. difficile genome resulting from the identification of transcriptional start sites (TSS), promoter motifs and operon structures. By 5′-end RNA-seq approach, we mapped more than 1000 TSS upstream of genes. In addition to these primary TSS, this analysis revealed complex structure of transcriptional units such as alternative and internal promoters, potential RNA processing events and 5′ untranslated regions. By following an in silico iterative strategy that used as an input previously published consensus sequences and transcriptomic analysis, we identified candidate promoters upstream of most of protein-coding and non-coding RNAs genes. This strategy also led to refine consensus sequences of promoters recognized by major sigma factors of C. difficile. Detailed analysis focuses on the transcription in the pathogenicity locus and regulatory genes, as well as regulons of transition phase and sporulation sigma factors as important components of C. difficile regulatory network governing toxin gene expression and spore formation. Among the still uncharacterized regulons of the major sigma factors of C. difficile, we defined the SigL regulon by combining transcriptome and in silico analyses. We showed that the SigL regulon is largely involved in amino-acid degradation, a metabolism crucial for C. difficile gut colonization. Finally, we combined our TSS mapping, in silico identification of promoters and RNA-seq data to improve gene annotation and to suggest operon organization in C. difficile. These data will considerably improve our knowledge of global regulatory circuits controlling gene expression in C. difficile and will serve as a useful rich resource for scientific community both for the detailed analysis of specific genes and systems biology studies.
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Affiliation(s)
- Olga Soutourina
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France.,Institut Universitaire de France, Paris, France.,Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Thomas Dubois
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | - Marc Monot
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | | | - Laure Saujet
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | - Pierre Boudry
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | - Mikhail S Gelfand
- Institute for Information Transmission Problems, Moscow, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Bruno Dupuy
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | - Isabelle Martin-Verstraete
- Laboratoire Pathogenèses des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France.,Institut Universitaire de France, Paris, France
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Isolation and Characterization of the Novel Phage JD032 and Global Transcriptomic Response during JD032 Infection of Clostridioides difficile Ribotype 078. mSystems 2020; 5:5/3/e00017-20. [PMID: 32371470 PMCID: PMC7205517 DOI: 10.1128/msystems.00017-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
C. difficile is one of the most clinically significant intestinal pathogens. Although phages have been shown to effectively control C. difficile infection, the host responses to phage predation have not been fully studied. In this study, we reported the isolation and characterization of a new phage, JD032, and analyzed the global transcriptomic changes in the hypervirulent RT078 C. difficile strain, TW11, during phage JD032 infection. We found that bacterial host mRNA was progressively replaced with phage transcripts, three temporal categories of JD032 gene expression, the extensive interplay between phage-bacterium, antiphage-like responses of the host and phage evasion, and decreased expression of sporulation- and virulence-related genes of the host after phage infection. These findings confirmed the complexity of interactions between C. difficile and phages and suggest that phages undergoing a lytic cycle may also cause different phenotypes in hosts, similar to prophages, which may inspire phage therapy for the control of C. difficile. Insights into the interaction between phages and their bacterial hosts are crucial for the development of phage therapy. However, only one study has investigated global gene expression of Clostridioides (formerly Clostridium) difficile carrying prophage, and transcriptional reprogramming during lytic infection has not been studied. Here, we presented the isolation, propagation, and characterization of a newly discovered 35,109-bp phage, JD032, and investigated the global transcriptomes of both JD032 and C. difficile ribotype 078 (RT078) strain TW11 during JD032 infection. Transcriptome sequencing (RNA-seq) revealed the progressive replacement of bacterial host mRNA with phage transcripts. The expressed genes of JD032 were clustered into early, middle, and late temporal categories that were functionally similar. Specifically, a gene (JD032_orf016) involved in the lysis-lysogeny decision was identified as an early expression gene. Only 17.7% (668/3,781) of the host genes were differentially expressed, and more genes were downregulated than upregulated. The expression of genes involved in host macromolecular synthesis (DNA/RNA/proteins) was altered by JD032 at the level of transcription. In particular, the expression of the ropA operon was downregulated. Most noteworthy is that the gene expression of some antiphage systems, including CRISPR-Cas, restriction-modification, and toxin-antitoxin systems, was suppressed by JD032 during infection. In addition, bacterial sporulation, adhesion, and virulence factor genes were significantly downregulated. This study provides the first description of the interaction between anaerobic spore-forming bacteria and phages during lytic infection and highlights new aspects of C. difficile phage-host interactions. IMPORTANCEC. difficile is one of the most clinically significant intestinal pathogens. Although phages have been shown to effectively control C. difficile infection, the host responses to phage predation have not been fully studied. In this study, we reported the isolation and characterization of a new phage, JD032, and analyzed the global transcriptomic changes in the hypervirulent RT078 C. difficile strain, TW11, during phage JD032 infection. We found that bacterial host mRNA was progressively replaced with phage transcripts, three temporal categories of JD032 gene expression, the extensive interplay between phage-bacterium, antiphage-like responses of the host and phage evasion, and decreased expression of sporulation- and virulence-related genes of the host after phage infection. These findings confirmed the complexity of interactions between C. difficile and phages and suggest that phages undergoing a lytic cycle may also cause different phenotypes in hosts, similar to prophages, which may inspire phage therapy for the control of C. difficile.
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Pellissery AJ, Vinayamohan PG, Venkitanarayanan K. In vitro antivirulence activity of baicalin against Clostridioides difficile. J Med Microbiol 2020; 69:631-639. [DOI: 10.1099/jmm.0.001179] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Introduction.
Clostridioides difficile
is an enteric pathogen that causes a serious toxin-mediated colitis in humans. Bacterial exotoxins and sporulation are critical virulence components that contribute to pathogenesis, and disease transmission and relapse, respectively. Therefore, reducing toxin production and sporulation could significantly minimize
C. difficile
pathogenicity and disease outcome in affected individuals.
Aim. This study investigated the efficacy of a natural flavone glycoside, baicalin, in reducing toxin synthesis, sporulation and spore germination in C. difficile in vitro.
Methodology. Hypervirulent
C. difficile
isolates BAA 1870 or 1803 were cultured in brain heart infusion broth with or without the subinhibitory concentration (SIC) of baicalin, and incubated at 37 °C for 24 h under strictly anaerobic conditions. The supernatant was harvested after 24 h for determining
C. difficile
toxin production by ELISA. In addition, a similar experiment was performed wherein samples were harvested for assessing total viable counts, and heat-resistant spore counts at 72 h of incubation. Furthermore,
C. difficile
spore germination and spore outgrowth kinetics, with or without baicalin treatment, was measured in a plate reader by recording optical density at 600 nm. Finally, the effect of baicalin on
C. difficile
toxin, sporulation and virulence-associated genes was investigated using real-time quantitative PCR.
Results. The SIC of baicalin significantly reduced toxin synthesis, sporulation and spore outgrowth when compared to control. In addition,
C. difficile
genes critical for pathogenesis were significantly down-regulated in the presence of baicalin.
Conclusion. Our results suggest that baicalin could potentially be used to control
C. difficile
, and warrant future studies in vivo.
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Shen A, Edwards AN, Sarker MR, Paredes-Sabja D. Sporulation and Germination in Clostridial Pathogens. Microbiol Spectr 2019; 7:10.1128/microbiolspec.GPP3-0017-2018. [PMID: 31858953 PMCID: PMC6927485 DOI: 10.1128/microbiolspec.gpp3-0017-2018] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Indexed: 12/14/2022] Open
Abstract
As obligate anaerobes, clostridial pathogens depend on their metabolically dormant, oxygen-tolerant spore form to transmit disease. However, the molecular mechanisms by which those spores germinate to initiate infection and then form new spores to transmit infection remain poorly understood. While sporulation and germination have been well characterized in Bacillus subtilis and Bacillus anthracis, striking differences in the regulation of these processes have been observed between the bacilli and the clostridia, with even some conserved proteins exhibiting differences in their requirements and functions. Here, we review our current understanding of how clostridial pathogens, specifically Clostridium perfringens, Clostridium botulinum, and Clostridioides difficile, induce sporulation in response to environmental cues, assemble resistant spores, and germinate metabolically dormant spores in response to environmental cues. We also discuss the direct relationship between toxin production and spore formation in these pathogens.
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Affiliation(s)
- Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University Medical School, Boston, MA
| | - Adrianne N Edwards
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA
| | - Mahfuzur R Sarker
- Department of Microbiology, College of Science, Oregon State University, Corvallis, OR
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR
| | - Daniel Paredes-Sabja
- Department of Gut Microbiota and Clostridia Research Group, Departamento de Ciencias Biolo gicas, Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile
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Clostridium difficile clade 3 (RT023) have a modified cell surface and contain a large transposable island with novel cargo. Sci Rep 2019; 9:15330. [PMID: 31653906 PMCID: PMC6814731 DOI: 10.1038/s41598-019-51628-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/02/2019] [Indexed: 12/16/2022] Open
Abstract
The major global pathogen Clostridium difficile (recently renamed Clostridioides difficile) has large genetic diversity including multiple mobile genetic elements. In this study, whole genome sequencing of 86 strains from the poorly characterised clade 3, predominantly PCR ribotype (RT)023, of C. difficile revealed distinctive surface architecture characteristics and a large mobile genetic island. These strains have a unique sortase substrate phenotype compared with well-characterised strains of C. difficile, and loss of the phage protection protein CwpV. A large genetic insertion (023_CTnT) comprised of three smaller elements (023_CTn1-3) is present in 80/86 strains analysed in this study, with genes common among other bacterial strains in the gut microbiome. Novel cargo regions of 023_CTnT include genes encoding a sortase, putative sortase substrates, lantibiotic ABC transporters and a putative siderophore biosynthetic cluster. We demonstrate the excision of 023_CTnT and sub-elements 023_CTn2 and 023_CTn3 from the genome of RT023 reference strain CD305 and the transfer of 023_CTn3 to a non-toxigenic C. difficile strain, which may have implications for the use of non-toxigenic C. difficile strains as live attenuated vaccines. Finally, we show that the genes within the island are expressed in a regulated manner in C. difficile RT023 strains conferring a distinct "niche adaptation".
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Using an Endogenous CRISPR-Cas System for Genome Editing in the Human Pathogen Clostridium difficile. Appl Environ Microbiol 2019; 85:AEM.01416-19. [PMID: 31399410 DOI: 10.1128/aem.01416-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 08/06/2019] [Indexed: 12/19/2022] Open
Abstract
The human enteropathogen Clostridium difficile constitutes a key public health issue in industrialized countries. Many aspects of C. difficile pathophysiology and adaptation inside the host remain poorly understood. We have recently reported that this bacterium possesses an active CRISPR-Cas system of subtype I-B for defense against phages and other mobile genetic elements that could contribute to its success during infection. In this paper, we demonstrate that redirecting this endogenous CRISPR-Cas system toward autoimmunity allows efficient genome editing in C. difficile We provide a detailed description of this newly developed approach and show, as a proof of principle, its efficient application for deletion of a specific gene in reference strain 630Δerm and in epidemic C. difficile strain R20291. The new method expands the arsenal of the currently limiting set of gene engineering tools available for investigation of C. difficile and may serve as the basis for new strategies to control C. difficile infections.IMPORTANCE Clostridium difficile represents today a real danger for human and animal health. It is the leading cause of diarrhea associated with health care in adults in industrialized countries. The incidence of these infections continues to increase, and this trend is accentuated by the general aging of the population. Many questions about the mechanisms contributing to C. difficile's success inside the host remain unanswered. The set of genetic tools available for this pathogen is limited, and new developments are badly needed. C. difficile has developed efficient defense systems that are directed against foreign DNA and that could contribute to its survival in phage-rich gut communities. We show how one such defense system, named CRISPR-Cas, can be hijacked for C. difficile genome editing. Our results also show a great potential for the use of the CRISPR-Cas system for the development of new therapeutic strategies against C. difficile infections.
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Ciftci Y, Girinathan BP, Dhungel BA, Hasan MK, Govind R. Clostridioides difficile SinR' regulates toxin, sporulation and motility through protein-protein interaction with SinR. Anaerobe 2019; 59:1-7. [PMID: 31077800 PMCID: PMC6785386 DOI: 10.1016/j.anaerobe.2019.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 04/10/2019] [Accepted: 05/07/2019] [Indexed: 12/18/2022]
Abstract
Clostridioides difficile is a Gram-positive, anaerobic bacterium. It is known that C. difficile is one of the major causes of antibiotic associated diarrhea. The enhanced antibiotic resistance observed in C. difficile is the result of highly resistant spores produced by the bacterium. In Bacillus subtilis, the sin operon is involved in sporulation inhibition. Two proteins coded within this operon, SinR and SinI, have an antagonistic relationship; SinR acts as an inhibitor to sporulation whereas SinI represses the activity of SinR, thus allowing the bacterium to sporulate. In a previous study, we examined the sin locus in C. difficile and named the two genes associated with this operon sinR and sinR', analogous to sinR and sinI in B. subtilis, respectively. We have shown that SinR and SinR' have pleiotropic roles in pathogenesis pathways and interact antagonistically with each other. Unlike B. subtilis SinI, SinR' in C. difficile carries two domains: the HTH domain and the Multimerization Domain (MD). In this study, we first performed a GST Pull-down experiment to determine the domain within SinR' that interacts with SinR. Second, the effect of these two domains on three phenotypes; sporulation, motility, and toxin production was examined. The findings of this study confirmed the prediction that the Multimerization Domain (MD) of SinR' is responsible for the interaction between SinR and SinR'. It was also discovered that SinR' regulates sporulation, toxin production and motility primarily by inhibiting SinR activity through the Multimerization Domain (MD).
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Affiliation(s)
- Yusuf Ciftci
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Brintha Parasumanna Girinathan
- Division of Biology, Kansas State University, Manhattan, KS, USA; Department of Pathology, Harvard Medical School, Boston, MA, USA
| | | | - Md Kamrul Hasan
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Revathi Govind
- Division of Biology, Kansas State University, Manhattan, KS, USA.
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Yuan Y, Zallot R, Grove TL, Payan DJ, Martin-Verstraete I, Šepić S, Balamkundu S, Neelakandan R, Gadi VK, Liu CF, Swairjo MA, Dedon PC, Almo SC, Gerlt JA, de Crécy-Lagard V. Discovery of novel bacterial queuine salvage enzymes and pathways in human pathogens. Proc Natl Acad Sci U S A 2019; 116:19126-19135. [PMID: 31481610 PMCID: PMC6754566 DOI: 10.1073/pnas.1909604116] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Queuosine (Q) is a complex tRNA modification widespread in eukaryotes and bacteria that contributes to the efficiency and accuracy of protein synthesis. Eukaryotes are not capable of Q synthesis and rely on salvage of the queuine base (q) as a Q precursor. While many bacteria are capable of Q de novo synthesis, salvage of the prokaryotic Q precursors preQ0 and preQ1 also occurs. With the exception of Escherichia coli YhhQ, shown to transport preQ0 and preQ1, the enzymes and transporters involved in Q salvage and recycling have not been well described. We discovered and characterized 2 Q salvage pathways present in many pathogenic and commensal bacteria. The first, found in the intracellular pathogen Chlamydia trachomatis, uses YhhQ and tRNA guanine transglycosylase (TGT) homologs that have changed substrate specificities to directly salvage q, mimicking the eukaryotic pathway. The second, found in bacteria from the gut flora such as Clostridioides difficile, salvages preQ1 from q through an unprecedented reaction catalyzed by a newly defined subgroup of the radical-SAM enzyme family. The source of q can be external through transport by members of the energy-coupling factor (ECF) family or internal through hydrolysis of Q by a dedicated nucleosidase. This work reinforces the concept that hosts and members of their associated microbiota compete for the salvage of Q precursors micronutrients.
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Affiliation(s)
- Yifeng Yuan
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611
| | - Rémi Zallot
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Tyler L Grove
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Daniel J Payan
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Isabelle Martin-Verstraete
- Laboratoire de Pathogénèse des Bactéries Anaérobies, Institut Pasteur et Université de Paris, F-75015 Paris, France
| | - Sara Šepić
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611
| | - Seetharamsingh Balamkundu
- Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, 138602 Singapore, Singapore
| | - Ramesh Neelakandan
- Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, 138602 Singapore, Singapore
| | - Vinod K Gadi
- Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, 138602 Singapore, Singapore
| | - Chuan-Fa Liu
- Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, 138602 Singapore, Singapore
| | - Manal A Swairjo
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182
- The Viral Information Institute, San Diego State University, San Diego, CA 92182
| | - Peter C Dedon
- Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, 138602 Singapore, Singapore
- Department of Biological Engineering and Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Steven C Almo
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - John A Gerlt
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611;
- University of Florida Genetics Institute, Gainesville, FL 32610
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44
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Tijerina-Rodríguez L, Villarreal-Treviño L, Baines SD, Morfín-Otero R, Camacho-Ortíz A, Flores-Treviño S, Maldonado-Garza H, Rodríguez-Noriega E, Garza-González E. High sporulation and overexpression of virulence factors in biofilms and reduced susceptibility to vancomycin and linezolid in recurrent Clostridium [Clostridioides] difficile infection isolates. PLoS One 2019; 14:e0220671. [PMID: 31365590 PMCID: PMC6668830 DOI: 10.1371/journal.pone.0220671] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/20/2019] [Indexed: 12/23/2022] Open
Abstract
Clostridium [Clostridioides] difficile infection (CDI) is one of the leading causes of diarrhea associated with medical care worldwide, and up to 60% of patients with CDI can develop a recurrent infection (R-CDI). A multi-species microbiota biofilm model of C. difficile was designed to evaluate the differences in the production of biofilms, sporulation, susceptibility to drugs, expression of sporulating (sigH, spo0A), quorum sensing (agrD1, and luxS), and adhesion-associated (slpA and cwp84) pathway genes between selected C. difficile isolates from R-CDI and non-recurrent patients (NR-CDI). We obtained 102 C. difficile isolates from 254 patients with confirmed CDI (66 from NR-CDI and 36 from R-CDI). Most of the isolates were biofilm producers, and most of the strains were ribotype 027 (81.374%, 83/102). Most C. difficile isolates were producers of biofilm (100/102), and most were strongly adherent. Sporulation was higher in the R-CDI than in the NR-CDI isolates (p = 0.015). The isolates from R-CDI patients more frequently demonstrated reduced susceptibility to vancomycin than isolates of NR-CDI patients (27.78% [10/36] and 9.09% [6/66], respectively, p = 0.013). The minimum inhibitory concentrations for vancomycin and linezolid against biofilms (BMIC) were up to 100 times and 20 times higher, respectively, than the corresponding planktonic MICs. Expression of sigH, spo0A, cwp84, and agrD1 was higher in R-CDI than in NR-CDI isolates. Most of the C. difficile isolates were producers of biofilms with no correlation with the ribotype. Sporulation was greater in R-CDI than in NR-CDI isolates in the biofilm model of C. difficile. The R-CDI isolates more frequently demonstrated reduced susceptibility to vancomycin and linezolid than the NR-CDI isolates in both planktonic cells and biofilm isolates. A higher expression of sporulating pathway (sigH, spo0A), quorum sensing (agrD1), and adhesion-associated (cwp84) genes was found in R-CDI than in NR-CDI isolates. All of these factors can have effect on the recurrence of the infection.
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Affiliation(s)
- Laura Tijerina-Rodríguez
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
| | - Licet Villarreal-Treviño
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
| | - Simon D. Baines
- Department of Biological and Environmental Sciences, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom
| | - Rayo Morfín-Otero
- Instituto de Patología Infecciosa y Experimental, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Hospital Civil de Guadalajara “Fray Antonio Alcalde”, Guadalajara, Mexico
| | - Adrián Camacho-Ortíz
- Hospital Universitario “Dr. José Eleuterio González”, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Samantha Flores-Treviño
- Hospital Universitario “Dr. José Eleuterio González”, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Héctor Maldonado-Garza
- Hospital Universitario “Dr. José Eleuterio González”, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Eduardo Rodríguez-Noriega
- Instituto de Patología Infecciosa y Experimental, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Hospital Civil de Guadalajara “Fray Antonio Alcalde”, Guadalajara, Mexico
| | - Elvira Garza-González
- Hospital Universitario “Dr. José Eleuterio González”, Universidad Autónoma de Nuevo León, Monterrey, Mexico
- * E-mail:
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45
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The Ser/Thr Kinase PrkC Participates in Cell Wall Homeostasis and Antimicrobial Resistance in Clostridium difficile. Infect Immun 2019; 87:IAI.00005-19. [PMID: 31085703 DOI: 10.1128/iai.00005-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/26/2019] [Indexed: 12/15/2022] Open
Abstract
Clostridium difficile is the leading cause of antibiotic-associated diarrhea in adults. During infection, C. difficile must detect the host environment and induce an appropriate survival strategy. Signal transduction networks involving serine/threonine kinases (STKs) play key roles in adaptation, as they regulate numerous physiological processes. PrkC of C. difficile is an STK with two PASTA domains. We showed that PrkC is membrane associated and is found at the septum. We observed that deletion of prkC affects cell morphology with an increase in mean size, cell length heterogeneity, and presence of abnormal septa. A ΔprkC mutant was able to sporulate and germinate but was less motile and formed more biofilm than the wild-type strain. Moreover, a ΔprkC mutant was more sensitive to antimicrobial compounds that target the cell envelope, such as the secondary bile salt deoxycholate, cephalosporins, cationic antimicrobial peptides, and lysozyme. This increased susceptibility was not associated with differences in peptidoglycan or polysaccharide II composition. However, the ΔprkC mutant had less peptidoglycan and released more polysaccharide II into the supernatant. A proteomic analysis showed that the majority of C. difficile proteins associated with the cell wall were less abundant in the ΔprkC mutant than the wild-type strain. Finally, in a hamster model of infection, the ΔprkC mutant had a colonization delay that did not significantly affect overall virulence.
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46
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Maikova A, Peltier J, Boudry P, Hajnsdorf E, Kint N, Monot M, Poquet I, Martin-Verstraete I, Dupuy B, Soutourina O. Discovery of new type I toxin-antitoxin systems adjacent to CRISPR arrays in Clostridium difficile. Nucleic Acids Res 2019. [PMID: 29529286 PMCID: PMC5961336 DOI: 10.1093/nar/gky124] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Clostridium difficile, a major human enteropathogen, must cope with foreign DNA invaders and multiple stress factors inside the host. We have recently provided an experimental evidence of defensive function of the C. difficile CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) system important for its survival within phage-rich gut communities. Here, we describe the identification of type I toxin-antitoxin (TA) systems with the first functional antisense RNAs in this pathogen. Through the analysis of deep-sequencing data, we demonstrate the general co-localization with CRISPR arrays for the majority of sequenced C. difficile strains. We provide a detailed characterization of the overlapping convergent transcripts for three selected TA pairs. The toxic nature of small membrane proteins is demonstrated by the growth arrest induced by their overexpression. The co-expression of antisense RNA acting as an antitoxin prevented this growth defect. Co-regulation of CRISPR-Cas and type I TA genes by the general stress response Sigma B and biofilm-related factors further suggests a possible link between these systems with a role in recurrent C. difficile infections. Our results provide the first description of genomic links between CRISPR and type I TA systems within defense islands in line with recently emerged concept of functional coupling of immunity and cell dormancy systems in prokaryotes.
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Affiliation(s)
- Anna Maikova
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France.,Center for Data-Intensive Biomedicine and Biotechnology, Skolkovo Institute of Science and Technology, Moscow 143028, Russia.,Peter the Great St.Petersburg Polytechnic University, Saint Petersburg 195251, Russia
| | - Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Pierre Boudry
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Eliane Hajnsdorf
- UMR8261 (CNRS-Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Nicolas Kint
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Marc Monot
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France.,Département de Microbiologie et d'infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, J1E 4K8, Sherbrooke, QC, Canada
| | - Isabelle Poquet
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,INRA, UMR1319 Micalis (Microbiologie de l'Alimentation au service de la Santé), Domaine de Vilvert, 78352, Jouy-en-Josas Cedex, France
| | - Isabelle Martin-Verstraete
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France
| | - Olga Soutourina
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 75724 Paris Cedex 15, France.,Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France.,Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
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47
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The σBsignalling activation pathway in the enteropathogenClostridioides difficile. Environ Microbiol 2019; 21:2852-2870. [DOI: 10.1111/1462-2920.14642] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/16/2019] [Accepted: 04/24/2019] [Indexed: 01/05/2023]
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48
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Bouillaut L, Dubois T, Francis MB, Daou N, Monot M, Sorg JA, Sonenshein AL, Dupuy B. Role of the global regulator Rex in control of NAD + -regeneration in Clostridioides (Clostridium) difficile. Mol Microbiol 2019; 111:1671-1688. [PMID: 30882947 DOI: 10.1111/mmi.14245] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2019] [Indexed: 12/31/2022]
Abstract
For the human pathogen Clostridioides (also known as Clostridium) difficile, the ability to adapt to nutrient availability is critical for its proliferation and production of toxins during infection. Synthesis of the toxins is regulated by the availability of certain carbon sources, fermentation products and amino acids (e.g. proline, cysteine, isoleucine, leucine and valine). The effect of proline is attributable at least in part to its role as an inducer and substrate of D-proline reductase (PR), a Stickland reaction that regenerates NAD+ from NADH. Many Clostridium spp. use Stickland metabolism (co-fermentation of pairs of amino acids) to generate ATP and NAD+ . Synthesis of PR is activated by PrdR, a proline-responsive regulatory protein. Here we report that PrdR, in the presence of proline, represses other NAD+ -generating pathways, such as the glycine reductase and succinate-acetyl CoA utilization pathways leading to butyrate production, but does so indirectly by affecting the activity of Rex, a global redox-sensing regulator that responds to the NAD+ /NADH ratio. Our results indicate that PR activity is the favored mechanism for NAD+ regeneration and that both Rex and PrdR influence toxin production. Using the hamster model of C. difficile infection, we revealed the importance of PrdR-regulated Stickland metabolism in the virulence of C. difficile.
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Affiliation(s)
- Laurent Bouillaut
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111
| | - Thomas Dubois
- Pathogenesis of Bacterial Anaerobes Laboratory, Institut Pasteur, 75724, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Michael B Francis
- Department of Biology, Texas A&M University, College Station, TX, 77843
| | - Nadine Daou
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111
| | - Marc Monot
- Pathogenesis of Bacterial Anaerobes Laboratory, Institut Pasteur, 75724, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Joseph A Sorg
- Department of Biology, Texas A&M University, College Station, TX, 77843
| | - Abraham L Sonenshein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111
| | - Bruno Dupuy
- Pathogenesis of Bacterial Anaerobes Laboratory, Institut Pasteur, 75724, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France
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49
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Edwards AN, Anjuwon-Foster BR, McBride SM. RstA Is a Major Regulator of Clostridioides difficile Toxin Production and Motility. mBio 2019; 10:e01991-18. [PMID: 30862746 PMCID: PMC6414698 DOI: 10.1128/mbio.01991-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 01/25/2019] [Indexed: 01/05/2023] Open
Abstract
Clostridioides difficile infection (CDI) is a toxin-mediated diarrheal disease. Several factors have been identified that influence the production of the two major C. difficile toxins, TcdA and TcdB, but prior published evidence suggested that additional unknown factors were involved in toxin regulation. Previously, we identified a C. difficile regulator, RstA, that promotes sporulation and represses motility and toxin production. We observed that the predicted DNA-binding domain of RstA was required for RstA-dependent repression of toxin genes, motility genes, and rstA transcription. In this study, we further investigated the regulation of toxin and motility gene expression by RstA. DNA pulldown assays confirmed that RstA directly binds the rstA promoter via the predicted DNA-binding domain. Through mutational analysis of the rstA promoter, we identified several nucleotides that are important for RstA-dependent transcriptional regulation. Further, we observed that RstA directly binds and regulates the promoters of the toxin genes tcdA and tcdB, as well as the promoters for the sigD and tcdR genes, which encode regulators of toxin gene expression. Complementation analyses with the Clostridium perfringens RstA ortholog and a multispecies chimeric RstA protein revealed that the C. difficile C-terminal domain is required for RstA DNA-binding activity, suggesting that species-specific signaling controls RstA function. Our data demonstrate that RstA is a transcriptional repressor that autoregulates its own expression and directly inhibits transcription of the two toxin genes and two positive toxin regulators, thereby acting at multiple regulatory points to control toxin production.IMPORTANCEClostridioides difficile is an anaerobic, gastrointestinal pathogen of humans and other mammals. C. difficile produces two major toxins, TcdA and TcdB, which cause the symptoms of the disease, and forms dormant endospores to survive the aerobic environment outside the host. A recently discovered regulatory factor, RstA, inhibits toxin production and positively influences spore formation. Herein, we determine that RstA directly binds its own promoter DNA to repress its own gene transcription. In addition, our data demonstrate that RstA directly represses toxin gene expression and gene expression of two toxin gene activators, TcdR and SigD, creating a complex regulatory network to tightly control toxin production. This study provides a novel regulatory link between C. difficile sporulation and toxin production. Further, our data suggest that C. difficile toxin production is regulated through a direct, species-specific sensing mechanism.
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Affiliation(s)
- Adrianne N Edwards
- Department of Microbiology and Immunology, Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Brandon R Anjuwon-Foster
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
| | - Shonna M McBride
- Department of Microbiology and Immunology, Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
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50
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Alves Feliciano C, Douché T, Giai Gianetto Q, Matondo M, Martin-Verstraete I, Dupuy B. CotL, a new morphogenetic spore coat protein of Clostridium difficile. Environ Microbiol 2019; 21:984-1003. [PMID: 30556639 DOI: 10.1111/1462-2920.14505] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 11/07/2018] [Accepted: 12/13/2018] [Indexed: 01/01/2023]
Abstract
The strict anaerobe Clostridium difficile is the most common cause of antibiotic-associated diarrhoea. The oxygen-resistant C. difficile spores play a central role in the infectious cycle, contributing to transmission, infection and recurrence. The spore surface layers, the coat and exosporium, enable the spores to resist physical and chemical stress. However, little is known about the mechanisms of their assembly. In this study, we characterized a new spore protein, CotL, which is required for the assembly of the spore coat. The cotL gene was expressed in the mother cell compartment under the dual control of the RNA polymerase sigma factors, σE and σK . CotL was localized in the spore coat, and the spores of the cotL mutant had a major morphologic defect at the level of the coat/exosporium layers. Therefore, the mutant spores contained a reduced amount of several coat/exosporium proteins and a defect in their localization in sporulating cells. Finally, cotL mutant spores were more sensitive to lysozyme and were impaired in germination, a phenotype likely to be associated with the structurally altered coat. Collectively, these results strongly suggest that CotL is a morphogenetic protein essential for the assembly of the spore coat in C. difficile.
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Affiliation(s)
- Carolina Alves Feliciano
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, Paris, France.,University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Thibaut Douché
- Plateforme Protéomique, Unité de Spectrométrie de Masse pour La Biologie, CNRS USR 2000, Institut Pasteur, Paris, France
| | - Quentin Giai Gianetto
- Plateforme Protéomique, Unité de Spectrométrie de Masse pour La Biologie, CNRS USR 2000, Institut Pasteur, Paris, France.,Bioinformatics and Biostatistics HUB, C3BI, CNRS USR 3756, Institut Pasteur, Paris, France
| | - Mariette Matondo
- Plateforme Protéomique, Unité de Spectrométrie de Masse pour La Biologie, CNRS USR 2000, Institut Pasteur, Paris, France
| | - Isabelle Martin-Verstraete
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, Paris, France.,University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, Paris, France.,University Paris Diderot, Sorbonne Paris Cité, Paris, France
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