1
|
Lin Q, Li Z, Ke H, Fei J, Zhang T, Wang P, Chen Y. Linked mutations within the pathogenicity locus of Clostridioides difficile increase virulence. Infect Dis (Lond) 2023; 55:847-856. [PMID: 37615633 DOI: 10.1080/23744235.2023.2249551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/14/2023] [Indexed: 08/25/2023] Open
Abstract
BACKGROUND The clinical manifestations of Clostridioides difficile infections range from diarrhoea to pseudomembranous colitis (PMC) and death. We evaluated the association between gene content in C. difficile clinical isolates and disease severity. METHODS Fifty-three C. difficile isolates were subjected to Sanger sequencing, clinical data were used to analyse the association of gene content with disease severity, and 83 non-duplicate isolates were collected to confirm the results. Virulence was further examined by functional in vitro and in vivo experiments. RESULTS Among the 53 C. difficile isolates, ribotypes 017 (n = 9, 17.0%) and 012 (n = 8, 15.1%) were predominant. Fifteen strains exhibited a correlation between mutations of pathogenicity locus genes (tcdB, tcdC, tcdR, and tcdE) and were named linked-mutation strains. Ribotypes are not associated with clinical PMC and Linked-mutation strains. The proportion of patients with PMC was higher in the group infected with linked-mutation strains than in the non-linked-mutation group (57.14% vs. 0%, p < 0.001). The linked-mutation rate of C. difficile was higher in patients with PMC than in patients without PMC (89.47% vs. 7.8%, p < 0.0001). Linked-mutation strains showed greater cytotoxicity in vitro and caused more severe tissue damage in a mouse model. CONCLUSIONS Linked-mutation strains are associated with high virulence and PMC development. This result will help monitor the clinical prognosis of C. difficile infection and provide key insights for developing therapeutic targets and monoclonal antibodies.
Collapse
Affiliation(s)
- Qianyun Lin
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zitong Li
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Haoran Ke
- Hepatology Unit, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jiaxi Fei
- Graceland Medical Center, the, Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ting Zhang
- Department of Gastroenterology, the Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Pu Wang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ye Chen
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Integrative Microecology Center, Department of Gastroenterology, Shenzhen Hospital, Southern Medical University, Shenzhen, China
| |
Collapse
|
2
|
Oliveira Paiva AM, de Jong L, Friggen AH, Smits WK, Corver J. The C-Terminal Domain of Clostridioides difficile TcdC Is Exposed on the Bacterial Cell Surface. J Bacteriol 2020; 202:JB.00771-19. [PMID: 32868401 PMCID: PMC7585056 DOI: 10.1128/jb.00771-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 08/25/2020] [Indexed: 02/04/2023] Open
Abstract
Clostridioides difficile is an anaerobic Gram-positive bacterium that can produce the large clostridial toxins toxin A and toxin B, encoded within the pathogenicity locus (PaLoc). The PaLoc also encodes the sigma factor TcdR, which positively regulates toxin gene expression, and TcdC, which is a putative negative regulator of toxin expression. TcdC is proposed to be an anti-sigma factor; however, several studies failed to show an association between the tcdC genotype and toxin production. Consequently, the TcdC function is not yet fully understood. Previous studies have characterized TcdC as a membrane-associated protein with the ability to bind G-quadruplex structures. The binding to the DNA secondary structures is mediated through the oligonucleotide/oligosaccharide binding fold (OB-fold) domain present at the C terminus of the protein. This domain was previously also proposed to be responsible for the inhibitory effect on toxin gene expression, implicating a cytoplasmic localization of the OB-fold. In this study, we aimed to obtain topological information on the C terminus of TcdC and demonstrate that the C terminus of TcdC is located extracellularly. In addition, we show that the membrane association of TcdC is dependent on a membrane-proximal cysteine residue and that mutating this residue results in the release of TcdC from the bacterial cell. The extracellular location of TcdC is not compatible with the direct binding of the OB-fold domain to intracellular nucleic acid or protein targets and suggests a mechanism of action that is different from that of the characterized anti-sigma factors.IMPORTANCE The transcription of C. difficile toxins TcdA and TcdB is directed by the sigma factor TcdR. TcdC has been proposed to be an anti-sigma factor. The activity of TcdC has been mapped to its C terminus, and the N terminus serves as the membrane anchor. Acting as an anti-sigma factor requires a cytoplasmic localization of the C terminus of TcdC. Using cysteine accessibility analysis and a HiBiT-based system, we show that the TcdC C terminus is located extracellularly, which is incompatible with its role as anti-sigma factor. Furthermore, mutating a cysteine residue at position 51 resulted in the release of TcdC from the bacteria. The codon-optimized version of the HiBiT (HiBiTopt) extracellular detection system is a valuable tool for topology determination of membrane proteins, increasing the range of systems available to tackle important aspects of C. difficile development.
Collapse
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
| | - Leen de Jong
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - 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
| | - 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
| | - Jeroen Corver
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| |
Collapse
|
3
|
Saito R, Usui Y, Ayibieke A, Nakajima J, Prah I, Sonobe K, Aiso Y, Ito S, Itsui Y, Hadano Y, Nukui Y, Koike R, Tohda S. Hypervirulent clade 2, ribotype 019/sequence type 67 Clostridioides difficile strain from Japan. Gut Pathog 2019; 11:54. [PMID: 31700548 PMCID: PMC6827173 DOI: 10.1186/s13099-019-0336-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/25/2019] [Indexed: 12/12/2022] Open
Abstract
Background Clostridioides difficile ribotype (RT) 019/sequence type (ST) 67 strains belong to a hypervirulent lineage closely related to RT027/ST1; however, limited data are available for hypervirulent clade 2 lineages in Japan. Herein, we report the draft genome of a C. difficile strain B18-123 belonging to clade 2, RT019/ST67 for the first time in Japan. Results The pathogenicity locus carried by B18-123 (19.6 kb) showed higher homology (97.29% nucleotide identity) with strain R20291 (RT027/ST1) than the reference strain 630 (RT012/ST54), and B18-123 harbored 8-nucleotide substitutions in tcdC. However, it did not contain an 18-base pair (bp) deletion or a single-bp deletion at position 117 in tcdC, which was identified in the previous strain R20291. A cytotoxicity assay revealed similar cytotoxicity levels between strains B18-123 and ATCC BAA-1870 (RT027/ST1). The B18-123 strain was found to be susceptible to metronidazole and vancomycin. Conclusion Our findings contribute to the further understanding of the characteristics of hypervirulent clade 2 including RT019/ST67 lineages.
Collapse
Affiliation(s)
- Ryoichi Saito
- 1Department of Molecular Microbiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,2Department of Infection Control and Prevention, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Yukino Usui
- 1Department of Molecular Microbiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Alafate Ayibieke
- 1Department of Molecular Microbiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Jun Nakajima
- 2Department of Infection Control and Prevention, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan.,3Department of Clinical Laboratory, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Isaac Prah
- 1Department of Molecular Microbiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kazunari Sonobe
- 2Department of Infection Control and Prevention, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan.,3Department of Clinical Laboratory, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Yoshibumi Aiso
- 2Department of Infection Control and Prevention, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Shiori Ito
- 4Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Yasuhiro Itsui
- 4Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Yoshiro Hadano
- 2Department of Infection Control and Prevention, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Yoko Nukui
- 2Department of Infection Control and Prevention, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Ryuji Koike
- 2Department of Infection Control and Prevention, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| | - Shuji Tohda
- 3Department of Clinical Laboratory, Tokyo Medical and Dental University Medical Hospital, Tokyo, Japan
| |
Collapse
|
4
|
Perrone R, Lavezzo E, Riello E, Manganelli R, Palù G, Toppo S, Provvedi R, Richter SN. Mapping and characterization of G-quadruplexes in Mycobacterium tuberculosis gene promoter regions. Sci Rep 2017; 7:5743. [PMID: 28720801 PMCID: PMC5515968 DOI: 10.1038/s41598-017-05867-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/02/2017] [Indexed: 12/04/2022] Open
Abstract
Mycobacterium tuberculosis is the causative agent of tuberculosis (TB), one of the top 10 causes of death worldwide in 2015. The recent emergence of strains resistant to all current drugs urges the development of compounds with new mechanisms of action. G-quadruplexes are nucleic acids secondary structures that may form in G-rich regions to epigenetically regulate cellular functions. Here we implemented a computational tool to scan the presence of putative G-quadruplex forming sequences in the genome of Mycobacterium tuberculosis and analyse their association to transcription start sites. We found that the most stable G-quadruplexes were in the promoter region of genes belonging to definite functional categories. Actual G-quadruplex folding of four selected sequences was assessed by biophysical and biomolecular techniques: all molecules formed stable G-quadruplexes, which were further stabilized by two G-quadruplex ligands. These compounds inhibited Mycobacterium tuberculosis growth with minimal inhibitory concentrations in the low micromolar range. These data support formation of Mycobacterium tuberculosis G-quadruplexes in vivo and their potential regulation of gene transcription, and prompt the use of G4 ligands to develop original antitubercular agents.
Collapse
Affiliation(s)
- Rosalba Perrone
- Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121, Padua, Italy
| | - Enrico Lavezzo
- Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121, Padua, Italy
| | - Erika Riello
- Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121, Padua, Italy
| | - Riccardo Manganelli
- Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121, Padua, Italy
| | - Giorgio Palù
- Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121, Padua, Italy
| | - Stefano Toppo
- Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121, Padua, Italy.
| | - Roberta Provvedi
- Department of Biology, University of Padua, via Ugo Bassi 58/b, 35121, Padua, Italy.
| | - Sara N Richter
- Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121, Padua, Italy.
| |
Collapse
|
5
|
Abstract
Clostridium difficile is the cause of antibiotics-associated diarrhea and pseudomembranous colitis. The pathogen produces three protein toxins: C. difficile toxins A (TcdA) and B (TcdB), and C. difficile transferase toxin (CDT). The single-chain toxins TcdA and TcdB are the main virulence factors. They bind to cell membrane receptors and are internalized. The N-terminal glucosyltransferase and autoprotease domains of the toxins translocate from low-pH endosomes into the cytosol. After activation by inositol hexakisphosphate (InsP6), the autoprotease cleaves and releases the glucosyltransferase domain into the cytosol, where GTP-binding proteins of the Rho/Ras family are mono-O-glucosylated and, thereby, inactivated. Inactivation of Rho proteins disturbs the organization of the cytoskeleton and affects multiple Rho-dependent cellular processes, including loss of epithelial barrier functions, induction of apoptosis, and inflammation. CDT, the third C. difficile toxin, is a binary actin-ADP-ribosylating toxin that causes depolymerization of actin, thereby inducing formation of the microtubule-based protrusions. Recent progress in understanding of the toxins' actions include insights into the toxin structures, their interaction with host cells, and functional consequences of their actions.
Collapse
Affiliation(s)
- Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany; , ,
| | - Carsten Schwan
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany; , ,
| | - Thomas Jank
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany; , ,
| |
Collapse
|
6
|
Whole genome sequences of three Clade 3 Clostridium difficile strains carrying binary toxin genes in China. Sci Rep 2017; 7:43555. [PMID: 28262711 PMCID: PMC5337907 DOI: 10.1038/srep43555] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/25/2017] [Indexed: 02/05/2023] Open
Abstract
Clostridium difficile consists of six clades but studies on Clade 3 are limited. Here, we report genome sequences of three Clade 3 C. difficile strains carrying genes encoding toxin A and B and the binary toxin. Isolates 103 and 133 (both of ST5) and isolate 106 (ST285) were recovered from three ICU patients. Whole genome sequencing using HiSeq 2500 revealed 4.1-Mb genomes with 28–29% GC content. There were ≥1,104 SNP between the isolates, suggesting they were not of a single clone. The toxin A and B gene-carrying pathogenicity locus (PaLoc) of the three isolates were identical and had the insertion of the transposon Tn6218. The genetic components of PaLoc among Clade 3 strains were the same with only a few nucleotide mutations and deletions/insertions, suggesting that the Tn6218 insertion might have occurred before the divergence within Clade 3. The binary toxin-genes carrying CDT locus (CdtLoc) of the three isolates were identical and were highly similar to those of other Clade 3 strains, but were more divergent from those of other clades. In conclusion, Clade 3 has an unusual clade-specific PaLoc characteristic of a Tn6218 insertion which appears to be the main feature to distinguish Clade 3 from other C. difficile.
Collapse
|
7
|
Abt MC, McKenney PT, Pamer EG. Clostridium difficile colitis: pathogenesis and host defence. Nat Rev Microbiol 2016; 14:609-20. [PMID: 27573580 DOI: 10.1038/nrmicro.2016.108] [Citation(s) in RCA: 331] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Clostridium difficile is a major cause of intestinal infection and diarrhoea in individuals following antibiotic treatment. Recent studies have begun to elucidate the mechanisms that induce spore formation and germination and have determined the roles of C. difficile toxins in disease pathogenesis. Exciting progress has also been made in defining the role of the microbiome, specific commensal bacterial species and host immunity in defence against infection with C. difficile. This Review will summarize the recent discoveries and developments in our understanding of C. difficile infection and pathogenesis.
Collapse
Affiliation(s)
- Michael C Abt
- Immunology Program, Lucille Castori Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA
| | - Peter T McKenney
- Immunology Program, Lucille Castori Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA
| | - Eric G Pamer
- Immunology Program, Lucille Castori Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA
| |
Collapse
|
8
|
Martin-Verstraete I, Peltier J, Dupuy B. The Regulatory Networks That Control Clostridium difficile Toxin Synthesis. Toxins (Basel) 2016; 8:E153. [PMID: 27187475 PMCID: PMC4885068 DOI: 10.3390/toxins8050153] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 05/03/2016] [Accepted: 05/05/2016] [Indexed: 12/19/2022] Open
Abstract
The pathogenic clostridia cause many human and animal diseases, which typically arise as a consequence of the production of potent exotoxins. Among the enterotoxic clostridia, Clostridium difficile is the main causative agent of nosocomial intestinal infections in adults with a compromised gut microbiota caused by antibiotic treatment. The symptoms of C. difficile infection are essentially caused by the production of two exotoxins: TcdA and TcdB. Moreover, for severe forms of disease, the spectrum of diseases caused by C. difficile has also been correlated to the levels of toxins that are produced during host infection. This observation strengthened the idea that the regulation of toxin synthesis is an important part of C. difficile pathogenesis. This review summarizes our current knowledge about the regulators and sigma factors that have been reported to control toxin gene expression in response to several environmental signals and stresses, including the availability of certain carbon sources and amino acids, or to signaling molecules, such as the autoinducing peptides of quorum sensing systems. The overlapping regulation of key metabolic pathways and toxin synthesis strongly suggests that toxin production is a complex response that is triggered by bacteria in response to particular states of nutrient availability during infection.
Collapse
Affiliation(s)
- Isabelle Martin-Verstraete
- Laboratoire Pathogenèse des Bactéries Anaérobes, Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux Paris, Paris 75015, France.
- UFR Sciences du vivant, University Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris 75015, France.
| | - Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobes, Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux Paris, Paris 75015, France.
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobes, Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux Paris, Paris 75015, France.
| |
Collapse
|
9
|
Janoir C. Virulence factors of Clostridium difficile and their role during infection. Anaerobe 2016; 37:13-24. [DOI: 10.1016/j.anaerobe.2015.10.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/16/2015] [Accepted: 10/21/2015] [Indexed: 02/08/2023]
|
10
|
Neisseria gonorrhoeae MutS affects pilin antigenic variation through mismatch correction and not by pilE guanine quartet binding. J Bacteriol 2015; 197:1828-38. [PMID: 25777677 DOI: 10.1128/jb.02594-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/08/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Many pathogens use homologous recombination to vary surface antigens to avoid immune surveillance. Neisseria gonorrhoeae achieves this in part by changing the properties of its surface pili in a process called pilin antigenic variation (AV). Pilin AV occurs by high-frequency gene conversion reactions that transfer silent pilS sequences into the expressed pilE locus and requires the formation of an upstream guanine quartet (G4) DNA structure to initiate this process. The MutS and MutL proteins of the mismatch correction (MMC) system act to correct mismatches after replication and prevent homeologous (i.e., partially homologous) recombination, but MutS orthologs can also bind to G4 structures. A previous study showed that mutation of MutS resulted in a 3-fold increase in pilin AV, which could be due to the loss of MutS antirecombination properties or loss of G4 binding. We tested two site-directed separation-of-function MutS mutants that are both predicted to bind to G4s but are not able to perform MMC. Pilus phase variation assays and DNA sequence analysis of pilE variants produced in these mutants showed that all three mutS mutants and a mutL mutant had similar increased frequencies of pilin AV. Moreover, the mutS mutants all showed similar increased levels of pilin AV-dependent synthetic lethality. These results show that antirecombination by MMC is the reason for the effect that MutS has on pilin AV and is not due to pilE G4 binding by MutS. IMPORTANCE Neisseria gonorrhoeae continually changes its outer surface proteins to avoid recognition by the immune system. N. gonorrhoeae alters the antigenicity of the pilus by directed recombination between partially homologous pilin copies in a process that requires a guanine quartet (G4) structure. The MutS protein of the mismatch correction (MMC) system prevents recombination between partially homologous sequences and can also bind to G4s. We confirmed that loss of MMC increases the frequency of pilin antigenic variation and that two MutS mutants that are predicted to separate the two different functions of MutS inhibit pilin variation similarly to a complete-loss-of-function mutant, suggesting that interaction of MutS with the G4 structure is not a major factor in this process.
Collapse
|
11
|
Bouillaut L, Dubois T, Sonenshein AL, Dupuy B. Integration of metabolism and virulence in Clostridium difficile. Res Microbiol 2014; 166:375-83. [PMID: 25445566 DOI: 10.1016/j.resmic.2014.10.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 10/06/2014] [Accepted: 10/07/2014] [Indexed: 01/04/2023]
Abstract
Synthesis of the major toxin proteins of the diarrheal pathogen, Clostridium difficile, is dependent on the activity of TcdR, an initiation (sigma) factor of RNA polymerase. The synthesis of TcdR and the activation of toxin gene expression are responsive to multiple components in the bacterium's nutritional environment, such as the presence of certain sugars, amino acids, and fatty acids. This review summarizes current knowledge about the mechanisms responsible for repression of toxin synthesis when glucose or branched-chain amino acids or proline are in excess and the pathways that lead to synthesis of butyrate, an activator of toxin synthesis. The regulatory proteins implicated in these mechanisms also play key roles in modulating bacterial metabolic pathways, suggesting that C. difficile pathogenesis is intimately connected to the bacterium's metabolic state.
Collapse
Affiliation(s)
- Laurent Bouillaut
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA.
| | - Thomas Dubois
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris, France.
| | - Abraham L Sonenshein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA.
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris, France.
| |
Collapse
|
12
|
Zhang S, Wu Y, Zhang W. G-Quadruplex Structures and Their Interaction Diversity with Ligands. ChemMedChem 2014; 9:899-911. [DOI: 10.1002/cmdc.201300566] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Indexed: 12/22/2022]
|
13
|
Jabbari S, Cartman ST, King JR. Mathematical modelling reveals properties of TcdC required for it to be a negative regulator of toxin production in Clostridium difficile. J Math Biol 2014; 70:773-804. [PMID: 24687436 PMCID: PMC4320785 DOI: 10.1007/s00285-014-0780-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 03/05/2014] [Indexed: 01/05/2023]
Abstract
The role of the protein TcdC in pathogenicity of the bacterium Clostridium difficile is currently unclear: conflicting reports suggest it is either a negative regulator of toxin production or, on the other hand, has no effect on virulence at all. We exploit a theoretical approach by taking what is known about the network of proteins surrounding toxin production by C. difficile and translating this into a mathematical model. From there it is possible to investigate a range of possible interactions (using numerical and asymptotic analyses), identifying properties of TcdC which would make it a realistic candidate as a toxin inhibitor. Our findings imply that if TcdC is really an inhibitor of toxin production then TcdC production should be at least as fast as that of the protein TcdR and TcdC should remain in the cells throughout growth. These are experimentally-testable hypotheses and are equally applicable to alternative candidates for toxin production inhibition.
Collapse
Affiliation(s)
- Sara Jabbari
- School of Mathematics and Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK,
| | | | | |
Collapse
|