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Nerber HN, Baloh M, Brehm JN, Sorg JA. The small acid-soluble proteins of Clostridioides difficile regulate sporulation in a SpoIVB2-dependent manner. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.17.541253. [PMID: 37292792 PMCID: PMC10245694 DOI: 10.1101/2023.05.17.541253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Clostridioides difficile is a pathogen whose transmission relies on the formation of dormant endospores. Spores are highly resilient forms of bacteria that resist environmental and chemical insults. In recent work, we found that C. difficile SspA and SspB, two small acid-soluble proteins (SASPs), protect spores from UV damage and, interestingly, are necessary for the formation of mature spores. Here, we build upon this finding and show that C. difficile sspA and sspB are required for the formation of the spore cortex layer. Moreover, using an EMS mutagenesis selection strategy, we identified mutations that suppressed the defect in sporulation of C. difficile SASP mutants. Many of these strains contained mutations in CDR20291_0714 (spoIVB2) revealing a connection between the SpoIVB2 protease and the SASPs in the sporulation pathway. This work builds upon the hypothesis that the small acid-soluble proteins can regulate gene expression.
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Affiliation(s)
- Hailee N Nerber
- Department of Biology, Texas A&M University, College Station, TX 77845
| | - Marko Baloh
- Department of Biology, Texas A&M University, College Station, TX 77845
| | - Joshua N Brehm
- Department of Biology, Texas A&M University, College Station, TX 77845
| | - Joseph A Sorg
- Department of Biology, Texas A&M University, College Station, TX 77845
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2
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Hu C, Garey KW. Microscopy methods for Clostridioides difficile. Anaerobe 2024; 86:102822. [PMID: 38341023 DOI: 10.1016/j.anaerobe.2024.102822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024]
Abstract
Microscopic technologies including light and fluorescent, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and cryo-electron microscopy have been widely utilized to visualize Clostridioides difficile at the molecular, cellular, community, and structural biology level. This comprehensive review summarizes the microscopy tools (fluorescent and reporter system) in their use to study different aspects of C. difficile life cycle and virulence (sporulation, germination) or applications (detection of C. difficile or use of antimicrobials). With these developing techniques, microscopy tools will be able to find broader applications and address more challenging questions to study C. difficile and C. difficile infection.
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Affiliation(s)
- Chenlin Hu
- University of Houston College of Pharmacy, Houston, TX, USA
| | - Kevin W Garey
- University of Houston College of Pharmacy, Houston, TX, USA.
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3
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Ribis JW, Melo L, Shrestha S, Giacalone D, Rodriguez EE, Shen A, Rohlfing A. Single-spore germination analyses reveal that calcium released during Clostridioides difficile germination functions in a feedforward loop. mSphere 2023; 8:e0000523. [PMID: 37338207 PMCID: PMC10449524 DOI: 10.1128/msphere.00005-23] [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: 01/18/2023] [Accepted: 04/21/2023] [Indexed: 06/21/2023] Open
Abstract
Clostridioides difficile infections begin when its metabolically dormant spores germinate in response to sensing bile acid germinants alongside amino acid and divalent cation co-germinants in the small intestine. While bile acid germinants are essential for C. difficile spore germination, it is currently unclear whether both co-germinant signals are required. One model proposes that divalent cations, particularly Ca2+, are essential for inducing germination, while another proposes that either co-germinant class can induce germination. The former model is based on the finding that spores defective in releasing large stores of internal Ca2+ in the form of calcium dipicolinic acid (CaDPA) cannot germinate when germination is induced with bile acid germinant and amino acid co-germinant alone. However, since the reduced optical density of CaDPA-less spores makes it difficult to accurately measure their germination, we developed a novel automated, time-lapse microscopy-based germination assay to analyze CaDPA mutant germination at the single-spore level. Using this assay, we found that CaDPA mutant spores germinate in the presence of amino acid co-germinant and bile acid germinant. Higher levels of amino acid co-germinants are nevertheless required to induce CaDPA mutant spores to germinate relative to WT spores because CaDPA released by WT spores during germination can function in a feedforward loop to potentiate the germination of other spores within the population. Collectively, these data indicate that Ca2+ is not essential for inducing C. difficile spore germination because amino acid and Ca2+ co-germinant signals are sensed by parallel signaling pathways. IMPORTANCE Clostridioides difficile spore germination is essential for this major nosocomial pathogen to initiate infection. C. difficile spores germinate in response to sensing bile acid germinant signals alongside co-germinant signals. There are two classes of co-germinant signals: Ca2+ and amino acids. Prior work suggested that Ca2+ is essential for C. difficile spore germination based on bulk population analyses of germinating CaDPA mutant spores. Since these assays rely on optical density to measure spore germination and the optical density of CaDPA mutant spores is reduced relative to WT spores, this bulk assay is limited in its capacity to analyze germination. To overcome this limitation, we developed an automated image analysis pipeline to monitor C. difficile spore germination using time-lapse microscopy. With this analysis pipeline, we demonstrate that, although Ca2+ is dispensable for inducing C. difficile spore germination, CaDPA can function in a feedforward loop to potentiate the germination of neighboring spores.
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Affiliation(s)
- John W. Ribis
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Luana Melo
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Shailab Shrestha
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - David Giacalone
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | | | - Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Amy Rohlfing
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Tufts University, Boston, Massachusetts, USA
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4
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Boamah D, Gilmore M, Bourget S, Ghosh A, Hossain M, Vogel J, Cava F, O’Connor T. Peptidoglycan deacetylation controls type IV secretion and the intracellular survival of the bacterial pathogen Legionella pneumophila. Proc Natl Acad Sci U S A 2023; 120:e2119658120. [PMID: 37252954 PMCID: PMC10266036 DOI: 10.1073/pnas.2119658120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 04/18/2023] [Indexed: 06/01/2023] Open
Abstract
Peptidoglycan is a critical component of the bacteria cell envelope. Remodeling of the peptidoglycan is required for numerous essential cellular processes and has been linked to bacterial pathogenesis. Peptidoglycan deacetylases that remove the acetyl group of the N-acetylglucosamine (NAG) subunit protect bacterial pathogens from immune recognition and digestive enzymes secreted at the site of infection. However, the full extent of this modification on bacterial physiology and pathogenesis is not known. Here, we identify a polysaccharide deacetylase of the intracellular bacterial pathogen Legionella pneumophila and define a two-tiered role for this enzyme in Legionella pathogenesis. First, NAG deacetylation is important for the proper localization and function of the Type IVb secretion system, linking peptidoglycan editing to the modulation of host cellular processes through the action of secreted virulence factors. As a consequence, the Legionella vacuole mis-traffics along the endocytic pathway to the lysosome, preventing the formation of a replication permissive compartment. Second, within the lysosome, the inability to deacetylate the peptidoglycan renders the bacteria more sensitive to lysozyme-mediated degradation, resulting in increased bacterial death. Thus, the ability to deacetylate NAG is important for bacteria to persist within host cells and in turn, Legionella virulence. Collectively, these results expand the function of peptidoglycan deacetylases in bacteria, linking peptidoglycan editing, Type IV secretion, and the intracellular fate of a bacterial pathogen.
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Affiliation(s)
- David Boamah
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Michael C. Gilmore
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå90187, Sweden
| | - Sarah Bourget
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Anushka Ghosh
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Mohammad J. Hossain
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Joseph P. Vogel
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO63110
| | - Felipe Cava
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå90187, Sweden
| | - Tamara J. O’Connor
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD21205
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5
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Abstract
Clostridioides difficile spores are the infective form for this endospore-forming organism. The vegetative cells are intolerant to oxygen and poor competitors with a healthy gut microbiota. Therefore, in order for C. difficile to establish infection, the spores have to germinate in an environment that supports vegetative growth. To initiate germination, C. difficile uses Csp-type germinant receptors that consist of the CspC and CspA pseudoproteases as the bile acid and cogerminant receptors, respectively. CspB is a subtilisin-like protease that cleaves the inhibitory propeptide from the pro-SleC cortex lytic enzyme, thereby activating it and initiating cortex degradation. Though several locations have been proposed for where these proteins reside within the spore (i.e., spore coat, outer spore membrane, cortex, and inner spore membrane), these have been based, mostly, on hypotheses or prior data in Clostridium perfringens. In this study, we visualized the germination and outgrowth process using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and used immunogold labeling to visualize key germination regulators. These analyses localize these key regulators to the spore cortex region for the first time. IMPORTANCE Germination by C. difficile spores is the first step in the establishment of potentially life-threatening C. difficile infection (CDI). A deeper understanding of the mechanism by which spores germinate may provide insight for how to either prevent spore germination into a disease-causing vegetative form or trigger germination prematurely when the spore is either in the outside environment or in a host environment that does not support the establishment of colonization/disease.
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Coullon H, Candela T. Clostridioides difficile peptidoglycan modifications. Curr Opin Microbiol 2021; 65:156-161. [PMID: 34883390 DOI: 10.1016/j.mib.2021.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/13/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022]
Abstract
The cortex and peptidoglycan of Clostridioides difficile have been poorly investigated. This last decade, the interest increased because these two structures are highly modified and these modifications may be involved in antimicrobial resistance. For example, C. difficile peptidoglycan deacetylation was recently reported to be involved in lysozyme resistance. Modifications may also be important for spore cortex synthesis or spore germination, which is essential in C. difficile pathogenesis. As such, the enzymes responsible for modifications of the peptidoglycan and/or cortex could be new drug target candidates or used as anti-C. difficile agents, as seen for the CD11 autolysin. In this review, we focus on C. difficile peptidoglycan and cortex and compare their structures with those of other well studied bacteria.
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Affiliation(s)
- Héloise Coullon
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France; Division of Infectious Diseases, Dept. of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Thomas Candela
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France.
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Clostridioides difficile SpoVAD and SpoVAE Interact and Are Required for Dipicolinic Acid Uptake into Spores. J Bacteriol 2021; 203:e0039421. [PMID: 34424035 DOI: 10.1128/jb.00394-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Clostridioides difficile spores, like the spores from most endospore-forming organisms, are a metabolically dormant stage of development with a complex structure that conveys considerable resistance to environmental conditions, e.g., wet heat. This resistance is due to the large amount of dipicolinic acid (DPA) that is taken up by the spore core, preventing rotational motion of the core proteins. DPA is synthesized by the mother cell, and its packaging into the spore core is mediated by the products of the spoVA operon, which has a variable number of genes, depending on the organism. C. difficile encodes 3 spoVA orthologues, spoVAC, spoVAD, and spoVAE. Prior work has shown that C. difficile SpoVAC is a mechanosensing protein responsible for DPA release from the spore core upon the initiation of germination. However, the roles of SpoVAD and SpoVAE remain unclear in C. difficile. In this study, we analyzed the roles of SpoVAD and SpoVAE and found that they are essential for DPA uptake into the spore, similar to SpoVAC. Using split luciferase protein interaction assays, we found that these proteins interact, and we propose a model where SpoVAC/SpoVAD/SpoVAE proteins interact at or near the inner spore membrane, and each member of the complex is essential for DPA uptake into the spore core. IMPORTANCE C. difficile spore heat resistance provides an avenue for it to survive the disinfection protocols in hospital and community settings. The spore heat resistance is mainly the consequence of the high DPA content within the spore core. By elucidating the mechanism by which DPA is taken up by the spore core, this study may provide insight into how to disrupt the spore heat resistance with the aim of making the current disinfection protocols more efficient at preventing the spread of C. difficile in the environment.
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Alves Feliciano C, Eckenroth BE, Diaz OR, Doublié S, Shen A. A lipoprotein allosterically activates the CwlD amidase during Clostridioides difficile spore formation. PLoS Genet 2021; 17:e1009791. [PMID: 34570752 PMCID: PMC8496864 DOI: 10.1371/journal.pgen.1009791] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/07/2021] [Accepted: 08/23/2021] [Indexed: 11/19/2022] Open
Abstract
Spore-forming pathogens like Clostridioides difficile depend on germination to initiate infection. During gemination, spores must degrade their cortex layer, which is a thick, protective layer of modified peptidoglycan. Cortex degradation depends on the presence of the spore-specific peptidoglycan modification, muramic-∂-lactam (MAL), which is specifically recognized by cortex lytic enzymes. In C. difficile, MAL production depends on the CwlD amidase and its binding partner, the GerS lipoprotein. To gain insight into how GerS regulates CwlD activity, we solved the crystal structure of the CwlD:GerS complex. In this structure, a GerS homodimer is bound to two CwlD monomers such that the CwlD active sites are exposed. Although CwlD structurally resembles amidase_3 family members, we found that CwlD does not bind Zn2+ stably on its own, unlike previously characterized amidase_3 enzymes. Instead, GerS binding to CwlD promotes CwlD binding to Zn2+, which is required for its catalytic mechanism. Thus, in determining the first structure of an amidase bound to its regulator, we reveal stabilization of Zn2+ co-factor binding as a novel mechanism for regulating bacterial amidase activity. Our results further suggest that allosteric regulation by binding partners may be a more widespread mode for regulating bacterial amidase activity than previously thought. Spore germination is essential for many spore-forming pathogens to initiate infection. In order for spores to germinate, they must degrade a thick, protective layer of cell wall known as the cortex. The enzymes that digest this layer selectively recognize the spore-specific cell wall modification, muramic-∂-lactam (MAL). MAL is made in part through the activity of the CwlD amidase, which is found in all spore-forming bacteria. While Bacillus subtilis CwlD appears to have amidase activity on its own, Clostridioides difficile CwlD activity depends on its binding partner, the GerS lipoprotein. To understand why C. difficile CwlD requires GerS, we determined the X-ray crystal structure of the CwlD:GerS complex and discovered that GerS binds to a site distant from CwlD’s active site. We also found that GerS stabilizes CwlD binding to its co-factor, Zn2+, indicating that GerS allosterically activates CwlD amidase. Notably, regulation at the level of Zn2+ binding has not previously been described for bacterial amidases, and GerS is the first protein to be shown to allosterically activate an amidase. Since binding partners of bacterial amidases were only first discovered 15 years ago, our results suggest that diverse mechanisms remain to be discovered for these critical enzymes.
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Affiliation(s)
- Carolina Alves Feliciano
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Brian E. Eckenroth
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, United States of America
| | - Oscar R. Diaz
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, United States of America
| | - Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Planas A. Peptidoglycan Deacetylases in Bacterial Cell Wall Remodeling and Pathogenesis. Curr Med Chem 2021; 29:1293-1312. [PMID: 34525907 DOI: 10.2174/0929867328666210915113723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/24/2021] [Accepted: 07/26/2021] [Indexed: 11/22/2022]
Abstract
The bacterial cell wall peptidoglycan (PG) is a dynamic structure that is constantly synthesized, re-modeled and degraded during bacterial division and growth. Post-synthetic modifications modulate the action of endogenous autolysis during PG lysis and remodeling for growth and sporulation, but also they are a mechanism used by pathogenic bacteria to evade the host innate immune system. Modifica-tions of the glycan backbone are limited to the C-2 amine and the C-6 hydroxyl moieties of either Glc-NAc or MurNAc residues. This paper reviews the functional roles and properties of peptidoglycan de-N-acetylases (distinct PG GlcNAc and MurNAc deacetylases) and recent progress through genetic stud-ies and biochemical characterization to elucidate their mechanism of action, 3D structures, substrate specificities and biological functions. Since they are virulence factors in pathogenic bacteria, peptidogly-can deacetylases are potential targets for the design of novel antimicrobial agents.
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Affiliation(s)
- Antoni Planas
- Laboratory of Biochemistry, Institut Químic de Sarrià. University Ramon Llull, 08017 Barcelona. Spain
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Shen A. Clostridioides difficile Spore Formation and Germination: New Insights and Opportunities for Intervention. Annu Rev Microbiol 2021; 74:545-566. [PMID: 32905755 DOI: 10.1146/annurev-micro-011320-011321] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Spore formation and germination are essential for the bacterial pathogen Clostridioides difficile to transmit infection. Despite the importance of these developmental processes to the infection cycle of C. difficile, the molecular mechanisms underlying how this obligate anaerobe forms infectious spores and how these spores germinate to initiate infection were largely unknown until recently. Work in the last decade has revealed that C. difficile uses a distinct mechanism for sensing and transducing germinant signals relative to previously characterized spore formers. The C. difficile spore assembly pathway also exhibits notable differences relative to Bacillus spp., where spore formation has been more extensively studied. For both these processes, factors that are conserved only in C. difficile or the related Peptostreptococcaceae family are employed, and even highly conserved spore proteins can have differential functions or requirements in C. difficile compared to other spore formers. This review summarizes our current understanding of the mechanisms controlling C. difficile spore formation and germination and describes strategies for inhibiting these processes to prevent C. difficile infection and disease recurrence.
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Affiliation(s)
- Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA;
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11
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A cortex-specific penicillin-binding protein contributes to heat resistance in Clostridioides difficile spores. Anaerobe 2021; 70:102379. [PMID: 33940167 PMCID: PMC8417463 DOI: 10.1016/j.anaerobe.2021.102379] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/23/2021] [Indexed: 12/15/2022]
Abstract
Background Sporulation is a complex cell differentiation programme shared by many members of the Firmicutes, the end result of which is a highly resistant, metabolically inert spore that can survive harsh environmental insults. Clostridioides difficile spores are essential for transmission of disease and are also required for recurrent infection. However, the molecular basis of sporulation is poorly understood, despite parallels with the well-studied Bacillus subtilis system. The spore envelope consists of multiple protective layers, one of which is a specialised layer of peptidoglycan, called the cortex, that is essential for the resistant properties of the spore. We set out to identify the enzymes required for synthesis of cortex peptidoglycan in C. difficile. Methods Bioinformatic analysis of the C. difficile genome to identify putative homologues of Bacillus subtilis spoVD was combined with directed mutagenesis and microscopy to identify and characterise cortex-specific PBP activity. Results Deletion of CDR20291_2544 (SpoVDCd) abrogated spore formation and this phenotype was completely restored by complementation in cis. Analysis of SpoVDCd revealed a three domain structure, consisting of dimerization, transpeptidase and PASTA domains, very similar to B. subtilis SpoVD. Complementation with SpoVDCd domain mutants demonstrated that the PASTA domain was dispensable for formation of morphologically normal spores. SpoVDCd was also seen to localise to the developing spore by super-resolution confocal microscopy. Conclusions We have identified and characterised a cortex specific PBP in C. difficile. This is the first characterisation of a cortex-specific PBP in C. difficile and begins the process of unravelling cortex biogenesis in this important pathogen. CDR20291_2544 encodes a C. difficile homologue of the B subtilis SpoVD. Mutation of spoVDCd completely prevents the formation of heat-resistant spores. The SpoVDCd PASTA domain was dispensable for its function. SpoVDCd localises to the developing spore.
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12
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Coullon H, Rifflet A, Wheeler R, Janoir C, Boneca IG, Candela T. Peptidoglycan analysis reveals that synergistic deacetylase activity in vegetative Clostridium difficile impacts the host response. J Biol Chem 2020; 295:16785-16796. [PMID: 32978253 PMCID: PMC7864072 DOI: 10.1074/jbc.ra119.012442] [Citation(s) in RCA: 8] [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: 12/30/2019] [Revised: 09/23/2020] [Indexed: 12/21/2022] Open
Abstract
Clostridium difficile is an anaerobic and spore-forming bacterium responsible for 15-25% of postantibiotic diarrhea and 95% of pseudomembranous colitis. Peptidoglycan is a crucial element of the bacterial cell wall that is exposed to the host, making it an important target for the innate immune system. The C. difficile peptidoglycan is largely N-deacetylated on its glucosamine (93% of muropeptides) through the activity of enzymes known as N-deacetylases, and this N-deacetylation modulates host-pathogen interactions, such as resistance to the bacteriolytic activity of lysozyme, virulence, and host innate immune responses. C. difficile genome analysis showed that 12 genes potentially encode N-deacetylases; however, which of these N-deacetylases are involved in peptidoglycan N-deacetylation remains unknown. Here, we report the enzymes responsible for peptidoglycan N-deacetylation and their respective regulation. Through peptidoglycan analysis of several mutants, we found that the N-deacetylases PdaV and PgdA act in synergy. Together they are responsible for the high level of peptidoglycan N-deacetylation in C. difficile and the consequent resistance to lysozyme. We also characterized a third enzyme, PgdB, as a glucosamine N-deacetylase. However, its impact on N-deacetylation and lysozyme resistance is limited, and its physiological role remains to be dissected. Finally, given the influence of peptidoglycan N-deacetylation on host defense against pathogens, we investigated the virulence and colonization ability of the mutants. Unlike what has been shown in other pathogenic bacteria, a lack of N-deacetylation in C. difficile is not linked to a decrease in virulence.
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Affiliation(s)
- Héloise Coullon
- Université Paris-Saclay, INRAE, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Aline Rifflet
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France; INSERM, Équipe Avenir, Paris; CNRS, UMR 2001 "Microbiologie Intégrative et Moléculaire," Paris, France
| | - Richard Wheeler
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France; INSERM, Équipe Avenir, Paris; CNRS, UMR 2001 "Microbiologie Intégrative et Moléculaire," Paris, France
| | - Claire Janoir
- Université Paris-Saclay, INRAE, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Ivo G Boneca
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France; INSERM, Équipe Avenir, Paris; CNRS, UMR 2001 "Microbiologie Intégrative et Moléculaire," Paris, France
| | - Thomas Candela
- Université Paris-Saclay, INRAE, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.
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13
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Pascual S, Planas A. Carbohydrate de-N-acetylases acting on structural polysaccharides and glycoconjugates. Curr Opin Chem Biol 2020; 61:9-18. [PMID: 33075728 DOI: 10.1016/j.cbpa.2020.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 12/14/2022]
Abstract
Deacetylation of N-acetylhexosamine residues in structural polysaccharides and glycoconjugates is catalyzed by different families of carbohydrate esterases that, despite different structural folds, share a common metal-assisted acid/base mechanism with the metal cation coordinated with a conserved Asp-His-His triad. These enzymes serve diverse biological functions in the modification of cell-surface polysaccharides in bacteria and fungi as well as in the metabolism of hexosamines in the biosynthesis of cellular glycoconjugates. Focusing on carbohydrate de-N-acetylases, this article summarizes the background of the different families from a structural and functional viewpoint and covers advances in the characterization of novel enzymes over the last 2-3 years. Current research is addressed to the identification of new deacetylases and unravel their biological functions as they are candidate targets for the design of antimicrobials against pathogenic bacteria and fungi. Likewise, some families are also used as biocatalysts for the production of defined glycostructures with diverse applications.
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Affiliation(s)
- Sergi Pascual
- Laboratory of Biochemistry, Institut Químic de Sarrià, University Ramon Llull, 08017, Barcelona, Spain
| | - Antoni Planas
- Laboratory of Biochemistry, Institut Químic de Sarrià, University Ramon Llull, 08017, Barcelona, Spain.
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14
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Deng G, Ji N, Shi X, Zhang W, Qin Y, Sha S, Yang S, Ma Y. Effects of Mycobacterium tuberculosis Rv1096 on mycobacterial cell division and modulation on macrophages. Microb Pathog 2020; 141:103991. [DOI: 10.1016/j.micpath.2020.103991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 01/19/2020] [Accepted: 01/20/2020] [Indexed: 12/11/2022]
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15
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Shen A. Clostridioides difficile Spores: Bile Acid Sensors and Trojan Horses of Transmission. Clin Colon Rectal Surg 2020; 33:58-66. [PMID: 32104157 DOI: 10.1055/s-0040-1701230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The Gram-positive, spore-forming bacterium, Clostridioides difficile is the leading cause of healthcare-associated infections in the United States, although it also causes a significant number of community-acquired infections. C. difficile infections, which range in severity from mild diarrhea to toxic megacolon, cost more to treat than matched infections, with an annual treatment cost of approximately $6 billion for almost half-a-million infections. These high-treatment costs are due to the high rates of C. difficile disease recurrence (>20%) and necessity for special disinfection measures. These complications arise in part because C. difficile makes metabolically dormant spores, which are the major infectious particle of this obligate anaerobe. These seemingly inanimate life forms are inert to antibiotics, resistant to commonly used disinfectants, readily disseminated, and capable of surviving in the environment for a long period of time. However, upon sensing specific bile salts in the vertebrate gut, C. difficile spores transform back into the vegetative cells that are responsible for causing disease. This review discusses how spores are ideal vectors for disease transmission and how antibiotics modulate this process. We also describe the resistance properties of spores and how they create challenges eradicating spores, as well as promote their spread. Lastly, environmental reservoirs of C. difficile spores and strategies for destroying them particularly in health care environments will be discussed.
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Affiliation(s)
- Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
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16
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Abhyankar W, Zheng L, Brul S, de Koster CG, de Koning LJ. Vegetative Cell and Spore Proteomes of Clostridioides difficile Show Finite Differences and Reveal Potential Protein Markers. J Proteome Res 2019; 18:3967-3976. [PMID: 31557040 PMCID: PMC6832669 DOI: 10.1021/acs.jproteome.9b00413] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Indexed: 12/22/2022]
Abstract
Clostridioides difficile-associated infection (CDI) is a health-care-associated infection caused, as the name suggests, by obligate anaerobic pathogen C. difficile and thus mainly transmitted via highly resistant endospores from one person to the other. In vivo, the spores need to germinate into cells prior to establishing an infection. Bile acids and glycine, both available in sufficient amounts inside the human host intestinal tract, serve as efficient germinants for the spores. It is therefore, for better understanding of C. difficile virulence, crucial to study both the cell and spore states with respect to their genetic, metabolic, and proteomic composition. In the present study, mass spectrometric relative protein quantification, based on the 14N/15N peptide isotopic ratios, has led to quantification of over 700 proteins from combined spore and cell samples. The analysis has revealed that the proteome turnover between a vegetative cell and a spore for this organism is moderate. Additionally, specific cell and spore surface proteins, vegetative cell proteins CD1228, CD3301 and spore proteins CD2487, CD2434, and CD0684 are identified as potential protein markers for C. difficile infection.
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Affiliation(s)
- Wishwas
R. Abhyankar
- Department
of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam Faculty
of Science, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Department
of Mass Spectrometry of Bio-Macromolecules, Swammerdam Institute for Life Sciences, University of Amsterdam Faculty
of Science, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Linli Zheng
- Department
of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam Faculty
of Science, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Department
of Mass Spectrometry of Bio-Macromolecules, Swammerdam Institute for Life Sciences, University of Amsterdam Faculty
of Science, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Stanley Brul
- Department
of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam Faculty
of Science, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Chris G. de Koster
- Department
of Mass Spectrometry of Bio-Macromolecules, Swammerdam Institute for Life Sciences, University of Amsterdam Faculty
of Science, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Leo J. de Koning
- Department
of Mass Spectrometry of Bio-Macromolecules, Swammerdam Institute for Life Sciences, University of Amsterdam Faculty
of Science, Science Park 904, 1098 XH Amsterdam, The Netherlands
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