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Zhou J, Horton JR, Menna M, Fiorentino F, Ren R, Yu D, Hajian T, Vedadi M, Mazzoccanti G, Ciogli A, Weinhold E, Hüben M, Blumenthal RM, Zhang X, Mai A, Rotili D, Cheng X. Systematic Design of Adenosine Analogs as Inhibitors of a Clostridioides difficile-Specific DNA Adenine Methyltransferase Required for Normal Sporulation and Persistence. J Med Chem 2023; 66:934-950. [PMID: 36581322 PMCID: PMC9841527 DOI: 10.1021/acs.jmedchem.2c01789] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Indexed: 12/31/2022]
Abstract
Antivirulence agents targeting endospore-transmitted Clostridioides difficile infections are urgently needed. C. difficile-specific DNA adenine methyltransferase (CamA) is required for efficient sporulation and affects persistence in the colon. The active site of CamA is conserved and closely resembles those of hundreds of related S-adenosyl-l-methionine (SAM)-dependent methyltransferases, which makes the design of selective inhibitors more challenging. We explored the solvent-exposed edge of the SAM adenosine moiety and systematically designed 42 analogs of adenosine carrying substituents at the C6-amino group (N6) of adenosine. We compare the inhibitory properties and binding affinity of these diverse compounds and present the crystal structures of CamA in complex with 14 of them in the presence of substrate DNA. The most potent of these inhibitors, compound 39 (IC50 ∼ 0.4 μM and KD ∼ 0.2 μM), is selective for CamA against closely related bacterial and mammalian DNA and RNA adenine methyltransferases, protein lysine and arginine methyltransferases, and human adenosine receptors.
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Affiliation(s)
- Jujun Zhou
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - John R. Horton
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Martina Menna
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Francesco Fiorentino
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Ren Ren
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Dan Yu
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Taraneh Hajian
- Structural
Genomics Consortium, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Masoud Vedadi
- Structural
Genomics Consortium, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department
of Pharmacology and Toxicology, University
of Toronto, Toronto, ON M5S 1A8, Canada
| | - Giulia Mazzoccanti
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Alessia Ciogli
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Elmar Weinhold
- Institute
of Organic Chemistry, RWTH Aachen University, D-52056 Aachen, Germany
| | - Michael Hüben
- Institute
of Organic Chemistry, RWTH Aachen University, D-52056 Aachen, Germany
| | - Robert M. Blumenthal
- Department
of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life
Sciences, Toledo, Ohio 43614, United States
| | - Xing Zhang
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Antonello Mai
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
- Pasteur
Institute, Cenci-Bolognetti Foundation, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Dante Rotili
- Department
of Drug Chemistry and Technologies, Sapienza
University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Xiaodong Cheng
- Department
of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
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Clark AE, Adamson CC, Carothers KE, Roxas BAP, Viswanathan VK, Vedantam G. The Alternative Sigma Factor SigL Influences Clostridioides difficile Toxin Production, Sporulation, and Cell Surface Properties. Front Microbiol 2022; 13:871152. [PMID: 35633701 PMCID: PMC9130780 DOI: 10.3389/fmicb.2022.871152] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/06/2022] [Indexed: 12/18/2022] Open
Abstract
The alternative sigma factor SigL (Sigma-54) facilitates bacterial adaptation to the extracellular environment by modulating the expression of defined gene subsets. A homolog of the gene encoding SigL is conserved in the diarrheagenic pathogen Clostridioides difficile. To explore the contribution of SigL to C. difficile biology, we generated sigL-disruption mutants (sigL::erm) in strains belonging to two phylogenetically distinct lineages-the human-relevant Ribotype 027 (strain BI-1) and the veterinary-relevant Ribotype 078 (strain CDC1). Comparative proteomics analyses of mutants and isogenic parental strains revealed lineage-specific SigL regulons. Concomitantly, loss of SigL resulted in pleiotropic and distinct phenotypic alterations in the two strains. Sporulation kinetics, biofilm formation, and cell surface-associated phenotypes were altered in CDC1 sigL::erm relative to the isogenic parent strain but remained unchanged in BI-1 sigL::erm. In contrast, secreted toxin levels were significantly elevated only in the BI-1 sigL::erm mutant relative to its isogenic parent. We also engineered SigL overexpressing strains and observed enhanced biofilm formation in the CDC1 background, and reduced spore titers as well as dampened sporulation kinetics in both strains. Thus, we contend that SigL is a key, pleiotropic regulator that dynamically influences C. difficile's virulence factor landscape, and thereby, its interactions with host tissues and co-resident microbes.
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Affiliation(s)
- Andrew E. Clark
- School of Animal and Comparative Biomedical Sciences, Tucson, AZ, United States
| | - Chelsea C. Adamson
- School of Animal and Comparative Biomedical Sciences, Tucson, AZ, United States
| | | | | | - V. K. Viswanathan
- School of Animal and Comparative Biomedical Sciences, Tucson, AZ, United States
- Department of Immunobiology, University of Arizona, Tucson, AZ, United States
- BIO5 Institute for Collaborative Research, University of Arizona, Tucson, AZ, United States
| | - Gayatri Vedantam
- School of Animal and Comparative Biomedical Sciences, Tucson, AZ, United States
- Department of Immunobiology, University of Arizona, Tucson, AZ, United States
- BIO5 Institute for Collaborative Research, University of Arizona, Tucson, AZ, United States
- Southern Arizona VA Healthcare System, Tucson, AZ, United States
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Chen J, Du Y, Lu Y, Wang H, Wu Q. Recent development of small-molecular inhibitors against Clostridioides difficile infection. Bioorg Chem 2022; 125:105843. [DOI: 10.1016/j.bioorg.2022.105843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 03/02/2022] [Accepted: 04/23/2022] [Indexed: 11/29/2022]
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McCarthy M, Goncalves M, Powell H, Morey B, Turner M, Merrill AR. A Structural Approach to Anti-Virulence: A Discovery Pipeline. Microorganisms 2021; 9:microorganisms9122514. [PMID: 34946116 PMCID: PMC8704661 DOI: 10.3390/microorganisms9122514] [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: 10/31/2021] [Revised: 11/27/2021] [Accepted: 11/30/2021] [Indexed: 11/25/2022] Open
Abstract
The anti-virulence strategy is designed to prevent bacterial virulence factors produced by pathogenic bacteria from initiating and sustaining an infection. One family of bacterial virulence factors is the mono-ADP-ribosyltransferase toxins, which are produced by pathogens as tools to compromise the target host cell. These toxins are bacterial enzymes that exploit host cellular NAD+ as the donor substrate to modify an essential macromolecule acceptor target in the host cell. This biochemical reaction modifies the target macromolecule (often protein or DNA) and functions in a binary fashion to turn the target activity on or off by blocking or impairing a critical process or pathway in the host. A structural biology approach to the anti-virulence method to neutralize the cytotoxic effect of these factors requires the search and design of small molecules that bind tightly to the enzyme active site and prevent catalytic function essentially disarming the pathogen. This method requires a high-resolution structure to serve as the model for small molecule inhibitor development, which illuminates the path to drug development. This alternative strategy to antibiotic therapy represents a paradigm shift that may circumvent multi-drug resistance in the offending microbe through anti-virulence therapy. In this report, the rationale for the anti-virulence structural approach will be discussed along with recent efforts to apply this method to treat honey bee diseases using natural products.
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Zhou J, Horton JR, Yu D, Ren R, Blumenthal RM, Zhang X, Cheng X. Repurposing epigenetic inhibitors to target the Clostridioides difficile-specific DNA adenine methyltransferase and sporulation regulator CamA. Epigenetics 2021; 17:970-981. [PMID: 34523387 PMCID: PMC9487755 DOI: 10.1080/15592294.2021.1976910] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Epigenetically targeted therapeutic development, particularly for SAM-dependent methylations of DNA, mRNA and histones has been proceeding rapidly for cancer treatments over the past few years. However, this approach has barely begun to be exploited for developing new antibiotics, despite an overwhelming global need to counter antimicrobial resistance. Here, we explore whether SAM analogues, some of which are in (pre)clinical studies as inhibitors of human epigenetic enzymes, can also inhibit Clostridioides difficile-specific DNA adenine methyltransferase (CamA), a sporulation regulator present in all C. difficile genomes sequenced to date, but found in almost no other bacteria. We found that SGC0946 (an inhibitor of DOT1L), JNJ-64619178 (an inhibitor of PRMT5) and SGC8158 (an inhibitor of PRMT7) inhibit CamA enzymatic activity in vitro at low micromolar concentrations. Structural investigation of the ternary complexes of CamA-DNA in the presence of SGC0946 or SGC8158 revealed conformational rearrangements of the N-terminal arm, with no apparent disturbance of the active site. This N-terminal arm and its modulation of exchanges between SAM (the methyl donor) and SAH (the reaction product) during catalysis of methyl transfer are, to date, unique to CamA. Our work presents a substantial first step in generating potent and selective inhibitors of CamA that would serve in the near term as chemical probes to investigate the cellular mechanism(s) of CamA in controlling spore formation and colonization, and eventually as therapeutic antivirulence agents useful in treating C. difficile infection.
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Affiliation(s)
- Jujun Zhou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Dan Yu
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ren Ren
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Zhou J, Horton JR, Blumenthal RM, Zhang X, Cheng X. Clostridioides difficile specific DNA adenine methyltransferase CamA squeezes and flips adenine out of DNA helix. Nat Commun 2021; 12:3436. [PMID: 34103525 PMCID: PMC8187626 DOI: 10.1038/s41467-021-23693-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/13/2021] [Indexed: 12/13/2022] Open
Abstract
Clostridioides difficile infections are an urgent medical problem. The newly discovered C. difficile adenine methyltransferase A (CamA) is specified by all C. difficile genomes sequenced to date (>300), but is rare among other bacteria. CamA is an orphan methyltransferase, unassociated with a restriction endonuclease. CamA-mediated methylation at CAAAAA is required for normal sporulation, biofilm formation, and intestinal colonization by C. difficile. We characterized CamA kinetic parameters, and determined its structure bound to DNA containing the recognition sequence. CamA contains an N-terminal domain for catalyzing methyl transfer, and a C-terminal DNA recognition domain. Major and minor groove DNA contacts in the recognition site involve base-specific hydrogen bonds, van der Waals contacts and the Watson-Crick pairing of a rearranged A:T base pair. These provide sufficient sequence discrimination to ensure high specificity. Finally, the surprisingly weak binding of the methyl donor S-adenosyl-L-methionine (SAM) might provide avenues for inhibiting CamA activity using SAM analogs.
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Affiliation(s)
- Jujun Zhou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Alharthi S, Alavi SE, Moyle PM, Ziora ZM. Sortase A (SrtA) inhibitors as an alternative treatment for superbug infections. Drug Discov Today 2021; 26:2164-2172. [PMID: 33781954 DOI: 10.1016/j.drudis.2021.03.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 03/01/2021] [Accepted: 03/19/2021] [Indexed: 12/28/2022]
Abstract
Virulence factor, sortase A (SrtA), has crucial roles in the pathogenesis of Gram-positive superbugs. SrtA is a bacterial cell membrane enzyme that anchors crucial virulence factors to the cell wall surface of Gram-positive bacteria. SrtA is not necessary for bacterial growth and viability and is conveniently accessible in the cell membrane; therefore, it is an ideal target for antivirulence drug development. In this review, we focus on antimicrobial resistance (AMR)-expressing bacteria and SrtA as a potential target for overcoming AMR. The mechanism of action of SrtA and its inhibition by various types of inhibitors, such as synthetic small molecules, peptides, and natural products, are provided. Future SrtA research perspectives for alternative drug development to antibiotics are also proposed.
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Affiliation(s)
- Sitah Alharthi
- School of Pharmacy, The University of Queensland, Woolloongabba, Qld 4102, Australia; Department of Pharmaceutical Science, School of Pharmacy, Shaqra University, Riyadh, Saudi Arabia
| | - Seyed Ebrahim Alavi
- School of Pharmacy, The University of Queensland, Woolloongabba, Qld 4102, Australia
| | - Peter Michael Moyle
- School of Pharmacy, The University of Queensland, Woolloongabba, Qld 4102, Australia.
| | - Zyta Maria Ziora
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4067, Australia.
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Weiss A. The therapeutic landscape for gut bacterial infections: opportunities and limitations. Gut Microbes 2020; 12:1. [PMID: 33092470 PMCID: PMC7588188 DOI: 10.1080/19490976.2020.1825076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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