1
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Affiliation(s)
- Megan Garland
- Cancer
Biology Program, ‡Department of Pathology, §Department of Microbiology and Immunology, and ∥Department of
Chemical and Systems Biology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - Sebastian Loscher
- Cancer
Biology Program, ‡Department of Pathology, §Department of Microbiology and Immunology, and ∥Department of
Chemical and Systems Biology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - Matthew Bogyo
- Cancer
Biology Program, ‡Department of Pathology, §Department of Microbiology and Immunology, and ∥Department of
Chemical and Systems Biology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
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2
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Zhang X, Amin EA. Highly predictive support vector machine (SVM) models for anthrax toxin lethal factor (LF) inhibitors. J Mol Graph Model 2016; 63:22-8. [PMID: 26615468 PMCID: PMC4713341 DOI: 10.1016/j.jmgm.2015.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 10/07/2015] [Accepted: 11/06/2015] [Indexed: 01/08/2023]
Abstract
Anthrax is a highly lethal, acute infectious disease caused by the rod-shaped, Gram-positive bacterium Bacillus anthracis. The anthrax toxin lethal factor (LF), a zinc metalloprotease secreted by the bacilli, plays a key role in anthrax pathogenesis and is chiefly responsible for anthrax-related toxemia and host death, partly via inactivation of mitogen-activated protein kinase kinase (MAPKK) enzymes and consequent disruption of key cellular signaling pathways. Antibiotics such as fluoroquinolones are capable of clearing the bacilli but have no effect on LF-mediated toxemia; LF itself therefore remains the preferred target for toxin inactivation. However, currently no LF inhibitor is available on the market as a therapeutic, partly due to the insufficiency of existing LF inhibitor scaffolds in terms of efficacy, selectivity, and toxicity. In the current work, we present novel support vector machine (SVM) models with high prediction accuracy that are designed to rapidly identify potential novel, structurally diverse LF inhibitor chemical matter from compound libraries. These SVM models were trained and validated using 508 compounds with published LF biological activity data and 847 inactive compounds deposited in the Pub Chem BioAssay database. One model, M1, demonstrated particularly favorable selectivity toward highly active compounds by correctly predicting 39 (95.12%) out of 41 nanomolar-level LF inhibitors, 46 (93.88%) out of 49 inactives, and 844 (99.65%) out of 847 Pub Chem inactives in external, unbiased test sets. These models are expected to facilitate the prediction of LF inhibitory activity for existing molecules, as well as identification of novel potential LF inhibitors from large datasets.
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Affiliation(s)
- Xia Zhang
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, 717 Delaware St. SE, Minneapolis, MN 55414-2959, United States
| | - Elizabeth Ambrose Amin
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, 717 Delaware St. SE, Minneapolis, MN 55414-2959, United States; Minnesota Supercomputing Institute for Advanced Computational Research, 117 Pleasant St SE, Minneapolis, MN, United States.
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3
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Green KD, Biswas T, Chang C, Wu R, Chen W, Janes BK, Chalupska D, Gornicki P, Hanna PC, Tsodikov OV, Joachimiak A, Garneau-Tsodikova S. Biochemical and structural analysis of an Eis family aminoglycoside acetyltransferase from bacillus anthracis. Biochemistry 2015; 54:3197-206. [PMID: 25928210 DOI: 10.1021/acs.biochem.5b00244] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Proteins from the enhanced intracellular survival (Eis) family are versatile acetyltransferases that acetylate amines at multiple positions of several aminoglycosides (AGs). Their upregulation confers drug resistance. Homologues of Eis are present in diverse bacteria, including many pathogens. Eis from Mycobacterium tuberculosis (Eis_Mtb) has been well characterized. In this study, we explored the AG specificity and catalytic efficiency of the Eis family protein from Bacillus anthracis (Eis_Ban). Kinetic analysis of specificity and catalytic efficiency of acetylation of six AGs indicates that Eis_Ban displays significant differences from Eis_Mtb in both substrate binding and catalytic efficiency. The number of acetylated amines was also different for several AGs, indicating a distinct regiospecificity of Eis_Ban. Furthermore, most recently identified inhibitors of Eis_Mtb did not inhibit Eis_Ban, underscoring the differences between these two enzymes. To explain these differences, we determined an Eis_Ban crystal structure. The comparison of the crystal structures of Eis_Ban and Eis_Mtb demonstrates that critical residues lining their respective substrate binding pockets differ substantially, explaining their distinct specificities. Our results suggest that acetyltransferases of the Eis family evolved divergently to garner distinct specificities while conserving catalytic efficiency, possibly to counter distinct chemical challenges. The unique specificity features of these enzymes can be utilized as tools for developing AGs with novel modifications and help guide specific AG treatments to avoid Eis-mediated resistance.
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Affiliation(s)
- Keith D Green
- ⊥Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky 40536-0596, United States
| | | | - Changsoo Chang
- ∇Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Ruiying Wu
- ∇Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | | | | | | | | | | | - Oleg V Tsodikov
- ⊥Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky 40536-0596, United States
| | - Andrzej Joachimiak
- ∇Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Sylvie Garneau-Tsodikova
- ⊥Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky 40536-0596, United States
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4
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Bouzianas DG. Potential biological targets ofBacillus anthracisin anti-infective approaches against the threat of bioterrorism. Expert Rev Anti Infect Ther 2014; 5:665-84. [PMID: 17678429 DOI: 10.1586/14787210.5.4.665] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The terrorist attacks of 2001 involving anthrax underscore the imperative that safe and effective medical countermeasures should be readily available. Vaccination appears to be the most effective form of mass protection against a biological attack, but the current vaccines have drawbacks that justify the enormous amount of effort currently being put into developing more effective vaccines and other treatment modalities. After providing a comprehensive overview of the organism Bacillus anthracis as a biological weapon and its pathogenicity, this review briefly summarizes the current knowledge vital to the management of anthrax disease. This knowledge has been acquired since 2001 as a result of the progress on anthrax research and focuses on the possible development of improved human anti-infective strategies targeting B. anthracis spore components, as well as strategies based on host-pathogen interactions.
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Affiliation(s)
- Dimitrios G Bouzianas
- Department of Medical Laboratories, Faculty of Health and Care Professions, University-level Technological Educational Institute of Thessaloniki, Greece.
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5
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Williams JD, Khan AR, Cardinale SC, Butler MM, Bowlin TL, Peet NP. Small molecule inhibitors of anthrax lethal factor toxin. Bioorg Med Chem 2013; 22:419-34. [PMID: 24290062 DOI: 10.1016/j.bmc.2013.11.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 10/29/2013] [Accepted: 11/05/2013] [Indexed: 10/26/2022]
Abstract
This manuscript describes the preparation of new small molecule inhibitors of Bacillus anthracis lethal factor. Our starting point was the symmetrical, bis-quinolinyl compound 1 (NSC 12155). Optimization of one half of this molecule led to new LF inhibitors that were desymmetrized to afford more drug-like compounds.
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Affiliation(s)
- John D Williams
- Microbiotix, Inc., Department of Medicinal Chemistry, One Innovation Drive, Worcester, MA 01605, United States; Microbiotix, Inc., Department of Molecular Biology, One Innovation Drive, Worcester, MA 01605, United States
| | - Atiyya R Khan
- Microbiotix, Inc., Department of Medicinal Chemistry, One Innovation Drive, Worcester, MA 01605, United States; Microbiotix, Inc., Department of Molecular Biology, One Innovation Drive, Worcester, MA 01605, United States
| | - Steven C Cardinale
- Microbiotix, Inc., Department of Medicinal Chemistry, One Innovation Drive, Worcester, MA 01605, United States; Microbiotix, Inc., Department of Molecular Biology, One Innovation Drive, Worcester, MA 01605, United States
| | - Michelle M Butler
- Microbiotix, Inc., Department of Medicinal Chemistry, One Innovation Drive, Worcester, MA 01605, United States; Microbiotix, Inc., Department of Molecular Biology, One Innovation Drive, Worcester, MA 01605, United States
| | - Terry L Bowlin
- Microbiotix, Inc., Department of Medicinal Chemistry, One Innovation Drive, Worcester, MA 01605, United States; Microbiotix, Inc., Department of Molecular Biology, One Innovation Drive, Worcester, MA 01605, United States
| | - Norton P Peet
- Microbiotix, Inc., Department of Medicinal Chemistry, One Innovation Drive, Worcester, MA 01605, United States; Microbiotix, Inc., Department of Molecular Biology, One Innovation Drive, Worcester, MA 01605, United States.
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6
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Chiu TL, Amin EA. Development of a comprehensive, validated pharmacophore hypothesis for anthrax toxin lethal factor (LF) inhibitors using genetic algorithms, Pareto scoring, and structural biology. J Chem Inf Model 2012; 52:1886-97. [PMID: 22697455 PMCID: PMC3477282 DOI: 10.1021/ci300121p] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis. The anthrax toxin lethal factor (LF), an 89-kDa zinc hydrolase secreted by the bacilli, is the toxin component chiefly responsible for pathogenesis and has been a popular target for rational and structure-based drug design. Although hundreds of small-molecule compounds have been designed to target the LF active site, relatively few reported inhibitors have exhibited activity in cell-based assays, and no LF inhibitor is currently available to treat or prevent anthrax. This study presents a new pharmacophore map assembly, validated by experiment, designed to rapidly identify and prioritize promising LF inhibitor scaffolds from virtual compound libraries. The new hypothesis incorporates structural information from all five available LF enzyme-inhibitor complexes deposited in the Protein Data Bank (PDB) and is the first LF pharmacophore map reported to date that includes features representing interactions involving all three key subsites of the LF catalytic binding region. In a wide-ranging validation study on all 546 compounds for which published LF biological activity data exist, this model displayed strong selectivity toward nanomolar-level LF inhibitors, successfully identifying 72.1% of existing nanomolar-level compounds in an unbiased test set, while rejecting 100% of weakly active (>100 μM) compounds. In addition to its capabilities as a database searching tool, this comprehensive model points to a number of key design principles and previously unidentified ligand-receptor interactions that are likely to influence compound potency.
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Affiliation(s)
- Ting-Lan Chiu
- Department of Medicinal Chemistry and Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, 717 Delaware St. SE, Minneapolis, Minnesota 55414-2959
| | - Elizabeth A. Amin
- Department of Medicinal Chemistry and Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, 717 Delaware St. SE, Minneapolis, Minnesota 55414-2959
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7
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Johnson SL, Chen LH, Barille E, Emdadi A, Sabet M, Yuan H, Wei J, Guiney D, Pellecchia M. Structure-activity relationship studies of a novel series of anthrax lethal factor inhibitors. Bioorg Med Chem 2009; 17:3352-68. [PMID: 19359184 PMCID: PMC2730741 DOI: 10.1016/j.bmc.2009.03.040] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 03/13/2009] [Accepted: 03/20/2009] [Indexed: 10/21/2022]
Abstract
We report on the identification of a novel small molecule inhibitor of anthrax lethal factor using a high-throughput screening approach. Guided by molecular docking studies, we carried out structure-activity relationship (SAR) studies and evaluated activity and selectivity of most promising compounds in in vitro enzyme inhibition assays and cellular assays. Selected compounds were further analyzed for their in vitro ADME properties, which allowed us to select two compounds for further preliminary in vivo efficacy studies. The data provided represents the basis for further pharmacology and medicinal chemistry optimizations that could result in novel anti-anthrax therapies.
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Affiliation(s)
- Sherida L. Johnson
- Burnham Institute for Medical Research, Cancer Research Center and Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Rd, La Jolla, CA 92037
| | - Li-Hsing Chen
- Burnham Institute for Medical Research, Cancer Research Center and Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Rd, La Jolla, CA 92037
| | - Elisa Barille
- Burnham Institute for Medical Research, Cancer Research Center and Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Rd, La Jolla, CA 92037
| | - Aras Emdadi
- Burnham Institute for Medical Research, Cancer Research Center and Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Rd, La Jolla, CA 92037
| | - Mojgan Sabet
- Department of Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Hongbin Yuan
- Burnham Institute for Medical Research, Cancer Research Center and Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Rd, La Jolla, CA 92037
| | - Jun Wei
- Burnham Institute for Medical Research, Cancer Research Center and Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Rd, La Jolla, CA 92037
| | - Donald Guiney
- Department of Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Maurizio Pellecchia
- Burnham Institute for Medical Research, Cancer Research Center and Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Rd, La Jolla, CA 92037
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8
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Agrawal A, de Oliveira CAF, Cheng Y, Jacobsen JA, McCammon JA, Cohen SM. Thioamide hydroxypyrothiones supersede amide hydroxypyrothiones in potency against anthrax lethal factor. J Med Chem 2009; 52:1063-74. [PMID: 19170530 PMCID: PMC2698031 DOI: 10.1021/jm8013212] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Anthrax lethal factor (LF) is a critical virulence factor in the pathogenesis of anthrax. A structure-activity relationship (SAR) of potential lethal factor inhibitors (LFi) is presented in which the zinc-binding group (ZBG), linker, and backbone moieties for a series of hydroxypyrone-based compounds were systematically varied. It was found that hydroxypyrothione ZBGs generate more potent inhibitors than hydroxypyrone ZBGs. Furthermore, coupling the hydroxypyrothione to a backbone group via a thioamide bond improves potency when compared to an amide linker. QM/MM studies show that the thioamide bond in these inhibitors allows for the formation of two additional hydrogen bonds with the protein active site. In both types of hydroxypyrothione compounds, ligand efficiencies of 0.29-0.54 kcal mol(-1) per heavy atom were achieved. The results highlight the need for a better understanding to optimize the interplay between the ZBG, linker, and backbone to get improved LFi.
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Affiliation(s)
- Arpita Agrawal
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093
| | - César Augusto F. de Oliveira
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093
- Howard Hughes Medical Institute, Center for Theoretical Biological Physics, Department of Chemistry and Biochemistry, Department of Pharmacology, University of California at San Diego, La Jolla, California 92093
| | - Yuhui Cheng
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093
- Howard Hughes Medical Institute, Center for Theoretical Biological Physics, Department of Chemistry and Biochemistry, Department of Pharmacology, University of California at San Diego, La Jolla, California 92093
| | - Jennifer A. Jacobsen
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093
| | - J. Andrew McCammon
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093
- Howard Hughes Medical Institute, Center for Theoretical Biological Physics, Department of Chemistry and Biochemistry, Department of Pharmacology, University of California at San Diego, La Jolla, California 92093
| | - Seth M. Cohen
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093
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Gaddis BD, Rubert Pérez CM, Chmielewski J. Inhibitors of anthrax lethal factor based upon N-oleoyldopamine. Bioorg Med Chem Lett 2008; 18:2467-70. [DOI: 10.1016/j.bmcl.2008.02.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/12/2008] [Accepted: 02/14/2008] [Indexed: 11/30/2022]
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10
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Berlinck RGS, Burtoloso ACB, Kossuga MH. The chemistry and biology of organic guanidine derivatives. Nat Prod Rep 2008; 25:919-54. [DOI: 10.1039/b507874c] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Gaddis BD, Avramova LV, Chmielewski J. Inhibitors of anthrax lethal factor. Bioorg Med Chem Lett 2007; 17:4575-8. [PMID: 17574849 DOI: 10.1016/j.bmcl.2007.05.089] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 05/24/2007] [Accepted: 05/30/2007] [Indexed: 10/23/2022]
Abstract
An inhibitor of anthrax lethal toxin mediated cell death (1) was identified by a medium throughput cell-based screen. This compound was determined to specifically inhibit anthrax lethal factor (LF), and subsequent SAR studies produced an even more potent inhibitor (4). Mechanistic studies identified these agents as uncompetitive inhibitors of LF with Ki values of 3.0 and 1.7 microM, respectively, with good cell potency and low cytotoxicity.
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Affiliation(s)
- Brandon D Gaddis
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
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12
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Li Y, Sherer K, Cui X, Eichacker PQ. New insights into the pathogenesis and treatment of anthrax toxin-induced shock. Expert Opin Biol Ther 2007; 7:843-54. [PMID: 17555370 DOI: 10.1517/14712598.7.6.843] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Inhalational Bacillus anthracis infection is a leading bioterrorist health threat in the US today. Lethal (LeTx) and edema toxin production are key to the virulent effects of this lethal bacteria. Recent insights into the structure and function of these toxins have increased the understanding of both the pathogenesis and treatment of anthrax. These are binary type toxins comprised of protective antigen necessary for their cellular uptake and either lethal or edema factors, the toxigenic moieties. Primary cellular receptors for protective antigen have been identified and the processing of the completed toxins clarified. Consistent with the ability of lethal factor to cleave mitogen activated protein kinase kinases, the evidence indicates that an excessive inflammatory response does not contribute to shock with LeTx. Rather, the immunosuppressive effects of LeTx could promote infection; however, direct endothelial dysfunction may have an important role in shock due to LeTx. Recent studies show that edema factor, a potent adenyl cyclase, may have a major role in shock during anthrax and that it may also be immunosuppresive. Therapies under development which target several steps in the cellular uptake and function of these two toxins have been effective in both in vitro and in vivo systems. Understanding how best to apply these agents in combination with conventional treatments should be a goal of future research.
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MESH Headings
- Adenylyl Cyclases/immunology
- Adenylyl Cyclases/metabolism
- Animals
- Anthrax/complications
- Anthrax/drug therapy
- Anthrax/metabolism
- Anthrax Vaccines/therapeutic use
- Antibodies, Monoclonal/therapeutic use
- Antigens, Bacterial/immunology
- Antigens, Bacterial/metabolism
- Bacillus anthracis/immunology
- Bacillus anthracis/metabolism
- Bacillus anthracis/pathogenicity
- Bacterial Toxins/immunology
- Bacterial Toxins/metabolism
- Endothelium, Vascular/microbiology
- Endothelium, Vascular/physiopathology
- Humans
- Receptors, Peptide/metabolism
- Shock, Septic/drug therapy
- Shock, Septic/metabolism
- Shock, Septic/microbiology
- Shock, Septic/physiopathology
- Virulence
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Affiliation(s)
- Yan Li
- National Institutes of Health, Critical Care Medicine Department, Clinical Center, Bethesda, MD 20892, USA
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Goldman ME, Cregar L, Nguyen D, Simo O, O'Malley S, Humphreys T. Cationic polyamines inhibit anthrax lethal factor protease. BMC Pharmacol 2006; 6:8. [PMID: 16762077 PMCID: PMC1513218 DOI: 10.1186/1471-2210-6-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Accepted: 06/08/2006] [Indexed: 11/12/2022] Open
Abstract
Background Anthrax is a human disease that results from infection by the bacteria, Bacillus anthracis and has recently been used as a bioterrorist agent. Historically, this disease was associated with Bacillus spore exposure from wool or animal carcasses. While current vaccine approaches (targeted against the protective antigen) are effective for prophylaxis, multiple doses must be injected. Common antibiotics that block the germination process are effective but must be administered early in the infection cycle. In addition, new therapeutics are needed to specifically target the proteolytic activity of lethal factor (LF) associated with this bacterial infection. Results Using a fluorescence-based assay to identify and characterize inhibitors of anthrax lethal factor protease activity, we identified several chemically-distinct classes of inhibitory molecules including polyamines, aminoglycosides and cationic peptides. In these studies, spermine was demonstrated for the first time to inhibit anthrax LF with a Ki value of 0.9 ± 0.09 μM (mean ± SEM; n = 3). Additional linear polyamines were also active as LF inhibitors with lower potencies. Conclusion Based upon the studies reported herein, we chose linear polyamines related to spermine as potential lead optimization candidates and additional testing in cell-based models where cell penetration could be studied. During our screening process, we reproducibly demonstrated that the potencies of certain compounds, including neomycin but not neamine or spermine, were different depending upon the presence or absence of nucleic acids. Differential sensitivity to the presence/absence of nucleic acids may be an additional point to consider when comparing various classes of active compounds for lead optimization.
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Affiliation(s)
| | - Lynne Cregar
- Hawaii Biotech, Inc., 99-193 Aiea Heights Dr., Aiea, HI 96701, USA
| | - Dominique Nguyen
- Hawaii Biotech, Inc., 99-193 Aiea Heights Dr., Aiea, HI 96701, USA
| | - Ondrej Simo
- Hawaii Biotech, Inc., 99-193 Aiea Heights Dr., Aiea, HI 96701, USA
| | - Sean O'Malley
- Hawaii Biotech, Inc., 99-193 Aiea Heights Dr., Aiea, HI 96701, USA
| | - Tom Humphreys
- Hawaii Biotech, Inc., 99-193 Aiea Heights Dr., Aiea, HI 96701, USA
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