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Li X, Zhang Y, Zhan Y, Tian H, Yan B, Cai J. Utilization of a strong promoter combined with the knockout of protease genes to improve the yield of Vip3Aa in Bacillus thuringiensis BMB171. PEST MANAGEMENT SCIENCE 2023; 79:1713-1720. [PMID: 36622044 DOI: 10.1002/ps.7343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 12/15/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Vip3Aa is an insecticidal protein secreted by some Bacillus thuringiensis strains during vegetative growth. It has excellent insecticidal activity, its mechanism of action is different from that of Cry protein, and it can delay the development of pest resistance. To date, Vip3Aa has been widely used in genetically modified Bt crops. However, the secretion of Vip3Aa by industrial production strains is usually very low. Moreover, most of the Vip3Aa in the medium is degraded by proteases, limiting its application as a biopesticide. RESULTS We report a novel constitutive strong promoter from B. thuringiensis, Prsi , which directs the abundant expression of vip3Aa in B. thuringiensis BMB171. Furthermore, to reduce the degradation of Vip3Aa caused by proteases, we constructed B. thuringiensis mutants in which different protease genes were knocked out. We found that the degradation of Vip3Aa was greatly inhibited and its yield was significantly improved in a mutant that lacked all three protease genes. CONCLUSION Our results provide a new strategy to enhance the production of Vip3Aa in B. thuringiensis and have reference value for the research and development of novel bioinsecticides. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Xuelian Li
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yanli Zhang
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yunda Zhan
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Hongwei Tian
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Bing Yan
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Jun Cai
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China
- Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, China
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2
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ERK and c-Myc signaling in host-derived tumor endothelial cells is essential for solid tumor growth. Proc Natl Acad Sci U S A 2023; 120:e2211927120. [PMID: 36574698 PMCID: PMC9910475 DOI: 10.1073/pnas.2211927120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The limited efficacy of the current antitumor microenvironment strategies is due in part to the poor understanding of the roles and relative contributions of the various tumor stromal cells to tumor development. Here, we describe a versatile in vivo anthrax toxin protein delivery system allowing for the unambiguous genetic evaluation of individual tumor stromal elements in cancer. Our reengineered tumor-selective anthrax toxin exhibits potent antiproliferative activity by disrupting ERK signaling in sensitive cells. Since this activity requires the surface expression of the capillary morphogenesis protein-2 (CMG2) toxin receptor, genetic manipulation of CMG2 expression using our cell-type-specific CMG2 transgenic mice allows us to specifically define the role of individual tumor stromal cell types in tumor development. Here, we established mice with CMG2 only expressed in tumor endothelial cells (ECs) and determined the specific contribution of tumor stromal ECs to the toxin's antitumor activity. Our results demonstrate that disruption of ERK signaling only within tumor ECs is sufficient to halt tumor growth. We discovered that c-Myc is a downstream effector of ERK signaling and that the MEK-ERK-c-Myc central metabolic axis in tumor ECs is essential for tumor progression. As such, disruption of ERK-c-Myc signaling in host-derived tumor ECs by our tumor-selective anthrax toxins explains their high efficacy in solid tumor therapy.
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Selective targeting of metastatic ovarian cancer using an engineered anthrax prodrug activated by membrane-anchored serine proteases. Proc Natl Acad Sci U S A 2022; 119:e2201423119. [PMID: 35867758 PMCID: PMC9282395 DOI: 10.1073/pnas.2201423119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Treatments for advanced and recurrent ovarian cancer remain a challenge due to a lack of potent, selective, and effective therapeutics. Here, we developed the basis for a transformative anticancer strategy based on anthrax toxin that has been engineered to be selectively activated by the catalytic power of zymogen-activating proteases on the surface of malignant tumor cells to induce cell death. Exposure to the engineered toxin is cytotoxic to ovarian tumor cell lines and ovarian tumor spheroids derived from patient ascites. Preclinical studies demonstrate that toxin treatment induces tumor regression in several in vivo ovarian cancer models, including patient-derived xenografts, without adverse side effects, supportive of progression toward clinical evaluation. These data lay the groundwork for developing therapeutics for treating women with late-stage and recurrent ovarian cancers, utilizing a mechanism distinct from current anticancer therapies.
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4
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Zuo Z, Liu J, Sun Z, Silverstein R, Zou M, Finkel T, Bugge TH, Leppla SH, Liu S. A potent tumor-selective ERK pathway inactivator with high therapeutic index. PNAS NEXUS 2022; 1:pgac104. [PMID: 35899070 PMCID: PMC9308561 DOI: 10.1093/pnasnexus/pgac104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 06/28/2022] [Indexed: 02/05/2023]
Abstract
FDA-approved BRAF and MEK small molecule inhibitors have demonstrated some level of efficacy in patients with metastatic melanomas. However, these "targeted" therapeutics have a very low therapeutic index, since these agents affect normal cells, causing undesirable, even fatal, side effects. To address these significant drawbacks, here, we have reengineered the anthrax toxin-based protein delivery system to develop a potent, tumor-selective MEK inactivator. This toxin-based MEK inactivator exhibits potent activity against a wide range of solid tumors, with the highest activity seen when directed toward tumors containing the BRAFV600E mutation. We demonstrate that this reengineered MEK inactivator also exhibits an extremely high therapeutic index (>15), due to its in vitro and in vivo activity being strictly dependent on the expression of multiple tumor-associated factors including tumor-associated proteases matrix metalloproteinase, urokinase plasminogen activator, and anthrax toxin receptor capillary morphogenesis protein-2. Furthermore, we have improved the specificity of this MEK inactivator, restricting its enzymatic activity to only target the ERK pathway, thereby greatly diminishing off-target toxicity. Together, these data suggest that engineered bacterial toxins can be modified to have significant in vitro and in vivo therapeutic effects with high therapeutic index.
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Affiliation(s)
| | | | - Zhihao Sun
- Aging Institute of University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, PA 15219, USA
| | - Rachel Silverstein
- Aging Institute of University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, PA 15219, USA
| | - Meijuan Zou
- Aging Institute of University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, PA 15219, USA
| | - Toren Finkel
- Aging Institute of University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, PA 15219, USA,Division of Cardiology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Thomas H Bugge
- Proteases and Tissue Remodeling Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Stephen H Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shihui Liu
- To whom correspondence should be addressed:
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5
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Yang NJ, Isensee J, Neel DV, Quadros AU, Zhang HXB, Lauzadis J, Liu SM, Shiers S, Belu A, Palan S, Marlin S, Maignel J, Kennedy-Curran A, Tong VS, Moayeri M, Röderer P, Nitzsche A, Lu M, Pentelute BL, Brüstle O, Tripathi V, Foster KA, Price TJ, Collier RJ, Leppla SH, Puopolo M, Bean BP, Cunha TM, Hucho T, Chiu IM. Anthrax toxins regulate pain signaling and can deliver molecular cargoes into ANTXR2 + DRG sensory neurons. Nat Neurosci 2021; 25:168-179. [PMID: 34931070 DOI: 10.1038/s41593-021-00973-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 11/01/2021] [Indexed: 11/09/2022]
Abstract
Bacterial products can act on neurons to alter signaling and function. In the present study, we found that dorsal root ganglion (DRG) sensory neurons are enriched for ANTXR2, the high-affinity receptor for anthrax toxins. Anthrax toxins are composed of protective antigen (PA), which binds to ANTXR2, and the protein cargoes edema factor (EF) and lethal factor (LF). Intrathecal administration of edema toxin (ET (PA + EF)) targeted DRG neurons and induced analgesia in mice. ET inhibited mechanical and thermal sensation, and pain caused by formalin, carrageenan or nerve injury. Analgesia depended on ANTXR2 expressed by Nav1.8+ or Advillin+ neurons. ET modulated protein kinase A signaling in mouse sensory and human induced pluripotent stem cell-derived sensory neurons, and attenuated spinal cord neurotransmission. We further engineered anthrax toxins to introduce exogenous protein cargoes, including botulinum toxin, into DRG neurons to silence pain. Our study highlights interactions between a bacterial toxin and nociceptors, which may lead to the development of new pain therapeutics.
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Affiliation(s)
- Nicole J Yang
- Department of Immunology, Harvard Medical School, Boston, MA, USA
| | - Jörg Isensee
- Translational Pain Research, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Dylan V Neel
- Department of Immunology, Harvard Medical School, Boston, MA, USA
| | - Andreza U Quadros
- Center for Research in Inflammatory Diseases, Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | | | - Justas Lauzadis
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, USA
| | | | - Stephanie Shiers
- Department of Neuroscience, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, USA
| | - Andreea Belu
- Translational Pain Research, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | | | | | | | | | - Victoria S Tong
- Department of Immunology, Harvard Medical School, Boston, MA, USA
| | - Mahtab Moayeri
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Pascal Röderer
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty and University Hospital Bonn, Bonn, Germany.,Cellomics Unit, LIFE & BRAIN GmbH, Bonn, Germany
| | - Anja Nitzsche
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty and University Hospital Bonn, Bonn, Germany.,Cellomics Unit, LIFE & BRAIN GmbH, Bonn, Germany
| | - Mike Lu
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Bradley L Pentelute
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.,The Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Oliver Brüstle
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty and University Hospital Bonn, Bonn, Germany
| | | | | | - Theodore J Price
- Department of Neuroscience, Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX, USA
| | - R John Collier
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Stephen H Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michelino Puopolo
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, USA
| | - Bruce P Bean
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Thiago M Cunha
- Center for Research in Inflammatory Diseases, Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Tim Hucho
- Translational Pain Research, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Isaac M Chiu
- Department of Immunology, Harvard Medical School, Boston, MA, USA.
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6
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Wang Y, Jiang N, Wang B, Tao H, Zhang X, Guan Q, Liu C. Integrated Transcriptomic and Proteomic Analyses Reveal the Role of NprR in Bacillus anthracis Extracellular Protease Expression Regulation and Oxidative Stress Responses. Front Microbiol 2020; 11:590851. [PMID: 33362738 PMCID: PMC7756075 DOI: 10.3389/fmicb.2020.590851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/18/2020] [Indexed: 12/18/2022] Open
Abstract
NprR is a protein of Bacillus anthracis that exhibits moonlighting functions as either a phosphatase or a neutral protease regulator that belongs to the RNPP family. We previously observed that the extracellular protease activity of an nprR deletion mutant significantly decreased within in vitro cultures. To identify the genes within the regulatory network of nprR that contribute to its protease activity, integrated transcriptomic and proteomic analyses were conducted here by comparing the nprR deletion mutant and parent strains. A total of 366 differentially expressed genes (DEGs) between the strains were observed via RNA-seq analysis. In addition, label-free LC-MS/MS analysis revealed 503 differentially expressed proteins (DEPs) within the intracellular protein fraction and 213 extracellular DEPs with significant expressional differences between the strains. The majority of DEGs and DEPs were involved in environmental information processing and metabolism. Integrated transcriptomic and proteomic analyses indicated that oxidation-reduction-related GO terms for intracellular DEPs and endopeptidase-related GO terms for extracellular DEPs were significantly enriched in the mutant strain. Notably, many genes involved in protease activity were largely downregulated in the nprR deletion mutant cultures. Moreover, western blot analysis revealed that the major extracellular neutral protease Npr599 was barely expressed in the nprR deletion mutant strain. The mutant also exhibited impaired degradation of protective antigen, which is a major B. anthracis toxin component, thereby resulting in higher protein yields. Concomitantly, another global transcriptional regulator, SpxA1, was also dramatically downregulated in the nprR deletion mutant, resulting in higher sensitivity to oxidative and disulfide stress. These data consequently indicate that NprR is a transcriptional regulator that controls genes whose products function as extracellular proteases and also is involved in oxidative stress responses. This study thus contributes to a more comprehensive understanding of the biological function of NprR, and especially in the middle growth stages of B. anthracis.
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Affiliation(s)
- Yanchun Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, China
| | - Na Jiang
- Beijing Fisheries Research Institute, Beijing, China
| | - Bowen Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, China
| | - Haoxia Tao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, China
| | - Xin Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, China
| | - Qing Guan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, China
| | - Chunjie Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, China
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7
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Liu J, Zuo Z, Zou M, Finkel T, Liu S. Identification of the transcription factor Miz1 as an essential regulator of diphthamide biosynthesis using a CRISPR-mediated genome-wide screen. PLoS Genet 2020; 16:e1009068. [PMID: 33057331 PMCID: PMC7591051 DOI: 10.1371/journal.pgen.1009068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 10/27/2020] [Accepted: 08/20/2020] [Indexed: 12/15/2022] Open
Abstract
Diphthamide is a unique post-translationally modified histidine residue (His715 in all mammals) found only in eukaryotic elongation factor-2 (eEF-2). The biosynthesis of diphthamide represents one of the most complex modifications, executed by protein factors conserved from yeast to humans. Diphthamide is not only essential for normal physiology (such as ensuring fidelity of mRNA translation), but is also exploited by bacterial ADP-ribosylating toxins (e.g., diphtheria toxin) as their molecular target in pathogenesis. Taking advantage of the observation that cells defective in diphthamide biosynthesis are resistant to ADP-ribosylating toxins, in the past four decades, seven essential genes (Dph1 to Dph7) have been identified for diphthamide biosynthesis. These technically unsaturated screens raise the question as to whether additional genes are required for diphthamide biosynthesis. In this study, we performed two independent, saturating, genome-wide CRISPR knockout screens in human cells. These screens identified all previously known Dph genes, as well as further identifying the BTB/POZ domain-containing transcription factor Miz1. We found that Miz1 is absolutely required for diphthamide biosynthesis via its role in the transcriptional regulation of Dph1 expression. Mechanistically, Miz1 binds to the Dph1 proximal promoter via an evolutionarily conserved consensus binding site to activate Dph1 transcription. Therefore, this work demonstrates that Dph1-7, along with the newly identified Miz1 transcription factor, are likely to represent the essential protein factors required for diphthamide modification on eEF2. Diphthamide is a unique post-translationally modified histidine residue (His699 in yeast, His715 in all mammals) found only in eukaryotic elongation factor-2 (eEF-2). Mice that are deficient in diphthamide biosynthesis are embryonic lethal, attesting to the importance of diphthamide in normal physiology. It has taken four decades to identify the seven non-redundant genes in diphthamide biosynthesis, but whether additional factors are required and how the pathway is regulated remained elusive. To address these issues, we performed two saturating, independent, and unbiased genome-wide CRISPR knockout screens. The screens concluded independently that Dph1-Dph7 and additionally transcription factor Miz1 are the key factors required for diphthamide biosynthesis. Mechanistically, Miz1 binds to the Dph1 proximal promoter via an evolutionarily conserved consensus binding site to activate Dph1 transcription. While diphthamide biosynthesis machinery (Dph1-Dph7) exists across eukaryotes, Miz1 orthologues do not exist in lower species such as yeast, C. elegans, and Drosophila, indicating that the regulation of diphthamide modification by Miz1 emerged much later in evolution. The work opens a new avenue for understanding the role that diphthamide modification plays in normal physiology and bacterial toxin pathogenesis.
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Affiliation(s)
- Jie Liu
- Aging Institute of University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, PA, United States of America
- Division of Cardiology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Zehua Zuo
- Aging Institute of University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, PA, United States of America
| | - Meijuan Zou
- Aging Institute of University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, PA, United States of America
| | - Toren Finkel
- Aging Institute of University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, PA, United States of America
- Division of Cardiology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Shihui Liu
- Aging Institute of University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, PA, United States of America
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
- * E-mail:
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8
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Exploring the Nature of Cationic Blocker Recognition by the Anthrax Toxin Channel. Biophys J 2019; 117:1751-1763. [PMID: 31587826 DOI: 10.1016/j.bpj.2019.08.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/11/2019] [Accepted: 08/05/2019] [Indexed: 01/20/2023] Open
Abstract
Obstructing conductive pathways of the channel-forming toxins with targeted blockers is a promising drug design approach. Nearly all tested positively charged ligands have been shown to reversibly block the cation-selective channel-forming protective antigen (PA63) component of the binary anthrax toxin. The cationic ligands with more hydrophobic surfaces, particularly those carrying aromatic moieties, inhibited PA63 more effectively. To understand the physical basis of PA63 selectivity for a particular ligand, detailed information is required on how the blocker structural elements (e.g., positively charged and aromatic groups) influence the molecular kinetics of the blocker/channel binding reactions. In this study, we address this problem using the high-resolution single-channel planar lipid bilayer technique. Several structurally distinct cationic blockers, namely per-6-S-(3-amino) propyl-β-cyclodextrin, per-6-S-(3-aminomethyl) benzyl-α-cyclodextrin, per-6-S-(3-aminomethyl) benzyl-β-cyclodextrin, per-6-S-(3-aminomethyl) benzyl-γ-cyclodextrin, methyltriphenylphosphonium ion, and G0 polyamidoamine dendrimer are tested for their ability to inhibit the heptameric and octameric PA63 variants and PA63F427A mutant. The F427 residues form a hydrophobic constriction region inside the channel, known as the "ϕ-clamp." We show that the cationic blockers interact with PA63 through a combination of forces. Analysis of the binding reaction kinetics suggests the involvement of cation-π, Coulomb, and salt-concentration-independent π-π or hydrophobic interactions in the cationic cyclodextrin binding. It is possible that these blockers bind to the ϕ-clamp and are also stabilized by the Coulomb interactions of their terminal amino groups with the water-exposed negatively charged channel residues. In PA63F427A, only the suggested Coulomb component of the cyclodextrin interaction remains. Methyltriphenylphosphonium ion and G0 polyamidoamine dendrimer, despite being positively charged, interact primarily with the ϕ-clamp. We also show that seven- and eightfold symmetric cyclodextrins effectively block the heptameric and octameric forms of PA63 interchangeably, adding flexibility to the earlier formulated blocker/target symmetry match requirement.
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Kondakova OA, Nikitin NA, Evtushenko EA, Ryabchevskaya EM, Atabekov JG, Karpova OV. Vaccines against anthrax based on recombinant protective antigen: problems and solutions. Expert Rev Vaccines 2019; 18:813-828. [PMID: 31298973 DOI: 10.1080/14760584.2019.1643242] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Introduction: Anthrax is a dangerous bio-terror agent because Bacillus anthracis spores are highly resilient and can be easily aerosolized and disseminated. There is a threat of deliberate use of anthrax spores aerosol that could lead to serious fatal diseases outbreaks. Existing control measures against inhalation form of the disease are limited. All of this has provided an impetus to the development of new generation vaccines. Areas сovered: This review is devoted to challenges and achievements in the design of vaccines based on the anthrax recombinant protective antigen (rPA). Scientific databases have been searched, focusing on causes of PA instability and solutions to this problem, including new approaches of rPA expression, novel rPA-based vaccines formulations as well as the simultaneous usage of PA with other anthrax antigens. Expert opinion: PA is a central anthrax toxin component, playing a key role in the defense against encapsulated and unencapsulated strains. Subunit rPA-based vaccines have a good safety and protective profile. However, there are problems of PA instability that are greatly enhanced when using aluminum adjuvants. New adjuvant compositions, dry formulations and resistant to proteolysis and deamidation mutant PA forms can help to handle this issue. Devising a modern anthrax vaccine requires huge efforts.
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Affiliation(s)
- Olga A Kondakova
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Nikolai A Nikitin
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Ekaterina A Evtushenko
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Ekaterina M Ryabchevskaya
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Joseph G Atabekov
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Olga V Karpova
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
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10
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Israeli M, Elia U, Rotem S, Cohen H, Tidhar A, Bercovich-Kinori A, Cohen O, Chitlaru T. Distinct Contribution of the HtrA Protease and PDZ Domains to Its Function in Stress Resilience and Virulence of Bacillus anthracis. Front Microbiol 2019; 10:255. [PMID: 30833938 PMCID: PMC6387919 DOI: 10.3389/fmicb.2019.00255] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 01/30/2019] [Indexed: 12/19/2022] Open
Abstract
Anthrax is a lethal disease caused by the Gram-positive spore-producing bacterium Bacillus anthracis. We previously demonstrated that disruption of htrA gene, encoding the chaperone/protease HtrABA (High Temperature Requirement A of B. anthracis) results in significant virulence attenuation, despite unaffected ability of ΔhtrA strains (in which the htrA gene was deleted) to synthesize the key anthrax virulence factors: the exotoxins and capsule. B. anthracis ΔhtrA strains exhibited increased sensitivity to stress regimens as well as silencing of the secreted starvation-associated Neutral Protease A (NprA) and down-modulation of the bacterial S-layer. The virulence attenuation associated with disruption of the htrA gene was suggested to reflect the susceptibility of ΔhtrA mutated strains to stress insults encountered in the host indicating that HtrABA represents an important B. anthracis pathogenesis determinant. As all HtrA serine proteases, HtrABA exhibits a protease catalytic domain and a PDZ domain. In the present study we interrogated the relative impact of the proteolytic activity (mediated by the protease domain) and the PDZ domain (presumably necessary for the chaperone activity and/or interaction with substrates) on manifestation of phenotypic characteristics mediated by HtrABA. By inspecting the phenotype exhibited by ΔhtrA strains trans-complemented with either a wild-type, truncated (ΔPDZ), or non-proteolytic form (mutated in the catalytic serine residue) of HtrABA, as well as strains exhibiting modified chromosomal alleles, it is shown that (i) the proteolytic activity of HtrABA is essential for its N-terminal autolysis and subsequent release into the extracellular milieu, while the PDZ domain was dispensable for this process, (ii) the PDZ domain appeared to be dispensable for most of the functions related to stress resilience as well as involvement of HtrABA in assembly of the bacterial S-layer, (iii) conversely, the proteolytic activity but not the PDZ domain, appeared to be dispensable for the role of HtrABA in mediating up-regulation of the extracellular protease NprA under starvation stress, and finally (iv) in a murine model of anthrax, the HtrABA PDZ domain, was dispensable for manifestation of B. anthracis virulence. The unexpected dispensability of the PDZ domain may represent a unique characteristic of HtrABA amongst bacterial serine proteases of the HtrA family.
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Affiliation(s)
- Ma'ayan Israeli
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Uri Elia
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Shahar Rotem
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Hila Cohen
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Avital Tidhar
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Adi Bercovich-Kinori
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Ofer Cohen
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Theodor Chitlaru
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
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11
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Haydar A, Tran SL, Guillemet E, Darrigo C, Perchat S, Lereclus D, Coquet L, Jouenne T, Ramarao N. InhA1-Mediated Cleavage of the Metalloprotease NprA Allows Bacillus cereus to Escape From Macrophages. Front Microbiol 2018; 9:1063. [PMID: 29875760 PMCID: PMC5974196 DOI: 10.3389/fmicb.2018.01063] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/04/2018] [Indexed: 12/20/2022] Open
Abstract
Bacillus cereus is a Gram-positive spore-forming bacterium causing food poisoning and serious opportunistic infections. These infections are characterized by bacterial accumulation in the host despite the induction of inflammation. To circumvent inflammation, bacteria must resist the bactericidal activity of professional phagocytes, which constitute a first line of host defense against pathogens. Interactions between phagocytic cells and B. cereus are still poorly characterized and the mechanism of resistance to the host immune system is not known yet. We have previously shown that the spores are phagocytosed by macrophages but survive and escape from these cells. The metalloprotease InhA1 is a key effector involved in these processes. inhA1-deficient spores are retained intracellularly, in contrast to the wild type strain spores. NprA is also a B. cereus metalloprotease able to cleave tissue components such as fibronectin, laminin, and collagen. Here, we show that NprA, concomitantly secreted with InhA1 in the B. cereus secretome, is essential to promote bacterial escape from macrophages. We show that InhA1 cleaves NprA at specific sites. This cleavage allows liberation of the mature form of the NprA protein in the supernatant of the wild type strain. This mature form of NprA is actually the principal effector allowing bacterial escape from host macrophages.
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Affiliation(s)
- Abbass Haydar
- INRA, Micalis Institute, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Seav-Ly Tran
- INRA, Micalis Institute, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Elisabeth Guillemet
- INRA, Micalis Institute, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Claire Darrigo
- INRA, Micalis Institute, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Stéphane Perchat
- INRA, Micalis Institute, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Didier Lereclus
- INRA, Micalis Institute, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Laurent Coquet
- CNRS, UMR 6270, Normandy University, UNIROUEN, Plate-forme PISSARO, Mont-Saint-Aignan, France
| | - Thierry Jouenne
- CNRS, UMR 6270, Normandy University, UNIROUEN, Plate-forme PISSARO, Mont-Saint-Aignan, France
| | - Nalini Ramarao
- INRA, Micalis Institute, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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12
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Genome engineering in Bacillus anthracis using tyrosine site-specific recombinases. PLoS One 2017; 12:e0183346. [PMID: 28829806 PMCID: PMC5567495 DOI: 10.1371/journal.pone.0183346] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/02/2017] [Indexed: 01/07/2023] Open
Abstract
Tyrosine site-specific recombinases (T-SSR) are polynucleotidyltransferases that catalyze cutting and joining reactions between short specific DNA sequences. We developed three systems for performing genetic modifications in Bacillus anthracis that use T-SSR and their cognate target sequences, namely Escherichia coli bacteriophage P1 Cre-loxP, Saccharomyces cerevisiae Flp-FRT, and a newly discovered IntXO-PSL system from B. anthracis plasmid pXO1. All three tyrosine recombinase systems were used for creation of a B. anthracis sporulation-deficient, plasmid-free strain deleted for ten proteases which had been identified by proteomic analysis as being present in the B. anthracis secretome. This strain was used successfully for production of various recombinant proteins, including several that are candidates for inclusion in improved anthrax vaccines. These genetic tools developed for DNA manipulation in B. anthracis were also used for construction of strains having chromosomal insertions of 1, 2, or 3 adjacent atxA genes. AtxA is a B. anthracis global transcriptional regulator required for the response of B. anthracis virulence factor genes to bicarbonate. We found a positive correlation between the atxA copy number and the expression level of the pagA gene encoding B. anthracis protective antigen, when strains were grown in a carbon dioxide atmosphere. These results demonstrate that the three T-SSR systems described here provide effective tools for B. anthracis genome editing. These T-SSR systems may also be applicable to other prokaryotes and to eukaryotes.
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13
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Liu S, Ma Q, Fattah R, Bugge TH, Leppla SH. Anti-tumor activity of anthrax toxin variants that form a functional translocation pore by intermolecular complementation. Oncotarget 2017; 8:65123-65131. [PMID: 29029417 PMCID: PMC5630317 DOI: 10.18632/oncotarget.17729] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/16/2017] [Indexed: 12/31/2022] Open
Abstract
Anthrax lethal toxin is a typical A-B type protein toxin secreted by Bacillus anthracis. Lethal factor (LF) is the catalytic A-subunit, a metalloprotease having MEKs as targets. LF relies on the cell-binding B-subunit, protective antigen (PA), to gain entry into the cytosol of target cells. PA binds to cell surface toxin receptors and is activated by furin protease to form an LF-binding-competent oligomer-PA pre-pore, which converts to a functional protein-conductive pore in the acidic endocytic vesicles, allowing translocation of LF into the cytosol. During PA pre-pore-to-pore conversion, the intermolecular salt bridge interactions between Lys397 and Asp426 on adjacent PA protomers play a critical role in positioning neighboring luminal Phe427 residues to form the Phe-clamp, an essential element of the PA functional pore. This essential intermolecular interaction affords the opportunity to create pairs of PA variants that depend on intermolecular complementation to form a functional pore. We have previously generated PA variants with furin-cleavage site replaced by substrate sequences of tumor-associated proteases, such as urokinase or MMPs. Here we show that PA-U2-K397Q, a urokinase-activated PA variant with Lys397 residue replaced by glutamine, and PA-L1-D426K, a MMP-activated PA variant with Asp426 changed to lysine, do not form functional pores both in vitro or in vivo unless they are used together. Further, the mixture of PA-U2-K397Q and PA-L1-D426K displayed potent anti-tumor activity in the presence of LF. Thus, PA-U2-K397Q and PA-L1-D426K form a novel intermolecular complementation system with toxin activation relying on the presence of two distinct tumor-associated proteases, i.e., urokinase and MMPs.
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Affiliation(s)
- Shihui Liu
- Proteases and Tissue Remodeling Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.,Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Qian Ma
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rasem Fattah
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Thomas H Bugge
- Proteases and Tissue Remodeling Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Stephen H Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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14
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Marino-Puertas L, Goulas T, Gomis-Rüth FX. Matrix metalloproteinases outside vertebrates. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2026-2035. [PMID: 28392403 DOI: 10.1016/j.bbamcr.2017.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 02/07/2023]
Abstract
The matrix metalloproteinase (MMP) family belongs to the metzincin clan of zinc-dependent metallopeptidases. Due to their enormous implications in physiology and disease, MMPs have mainly been studied in vertebrates. They are engaged in extracellular protein processing and degradation, and present extensive paralogy, with 23 forms in humans. One characteristic of MMPs is a ~165-residue catalytic domain (CD), which has been structurally studied for 14 MMPs from human, mouse, rat, pig and the oral-microbiome bacterium Tannerella forsythia. These studies revealed close overall coincidence and characteristic structural features, which distinguish MMPs from other metzincins and give rise to a sequence pattern for their identification. Here, we reviewed the literature available on MMPs outside vertebrates and performed database searches for potential MMP CDs in invertebrates, plants, fungi, viruses, protists, archaea and bacteria. These and previous results revealed that MMPs are widely present in several copies in Eumetazoa and higher plants (Tracheophyta), but have just token presence in eukaryotic algae. A few dozen sequences were found in Ascomycota (within fungi) and in double-stranded DNA viruses infecting invertebrates (within viruses). In contrast, a few hundred sequences were found in archaea and >1000 in bacteria, with several copies for some species. Most of the archaeal and bacterial phyla containing potential MMPs are present in human oral and gut microbiomes. Overall, MMP-like sequences are present across all kingdoms of life, but their asymmetric distribution contradicts the vertical descent model from a eubacterial or archaeal ancestor. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman.
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Affiliation(s)
- Laura Marino-Puertas
- Proteolysis Lab, Structural Biology Unit, "María-de-Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain
| | - Theodoros Goulas
- Proteolysis Lab, Structural Biology Unit, "María-de-Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain..
| | - F Xavier Gomis-Rüth
- Proteolysis Lab, Structural Biology Unit, "María-de-Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain..
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15
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Arolas JL, Goulas T, Pomerantsev AP, Leppla SH, Gomis-Rüth FX. Structural Basis for Latency and Function of Immune Inhibitor A Metallopeptidase, a Modulator of the Bacillus anthracis Secretome. Structure 2016; 24:25-36. [PMID: 26745529 DOI: 10.1016/j.str.2015.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 10/15/2015] [Accepted: 10/15/2015] [Indexed: 01/07/2023]
Abstract
Immune inhibitor A(InhA)-type metallopeptidases are potential virulence factors secreted by members of the Bacillus cereus group. Two paralogs from anthrax-causing Bacillus anthracis (BaInhA1 and BaInhA2) were shown to degrade host tissue proteins with broad substrate specificity. Analysis of their activation mechanism and the crystal structure of a zymogenic BaInhA2 variant revealed a ∼750-residue four-domain structure featuring a pro-peptide, a catalytic domain, a domain reminiscent of viral envelope glycoproteins, and a MAM domain grafted into the latter. This domain, previously found only in eukaryotes, is required for proper protein expression in B. anthracis and evinces certain flexibility. Latency is uniquely modulated by the N-terminal segment of the pro-peptide, which binds the catalytic zinc through its α-amino group and occupies the primed side of the active-site cleft. The present results further our understanding of the modus operandi of an anthrax secretome regulator.
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Affiliation(s)
- Joan L Arolas
- Proteolysis Lab, Department of Structural Biology ("María de Maeztu" Unit of Excellence), Molecular Biology Institute of Barcelona, Spanish Research Council (CSIC), Barcelona Science Park, Helix Building, Baldiri Reixac, 15-21, 08028 Barcelona, Spain
| | - Theodoros Goulas
- Proteolysis Lab, Department of Structural Biology ("María de Maeztu" Unit of Excellence), Molecular Biology Institute of Barcelona, Spanish Research Council (CSIC), Barcelona Science Park, Helix Building, Baldiri Reixac, 15-21, 08028 Barcelona, Spain
| | - Andrei P Pomerantsev
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Stephen H Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - F Xavier Gomis-Rüth
- Proteolysis Lab, Department of Structural Biology ("María de Maeztu" Unit of Excellence), Molecular Biology Institute of Barcelona, Spanish Research Council (CSIC), Barcelona Science Park, Helix Building, Baldiri Reixac, 15-21, 08028 Barcelona, Spain.
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16
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Martin EW, Buzza MS, Driesbaugh KH, Liu S, Fortenberry YM, Leppla SH, Antalis TM. Targeting the membrane-anchored serine protease testisin with a novel engineered anthrax toxin prodrug to kill tumor cells and reduce tumor burden. Oncotarget 2016; 6:33534-53. [PMID: 26392335 PMCID: PMC4741784 DOI: 10.18632/oncotarget.5214] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/03/2015] [Indexed: 02/04/2023] Open
Abstract
The membrane-anchored serine proteases are a unique group of trypsin-like serine proteases that are tethered to the cell surface via transmembrane domains or glycosyl-phosphatidylinositol-anchors. Overexpressed in tumors, with pro-tumorigenic properties, they are attractive targets for protease-activated prodrug-like anti-tumor therapies. Here, we sought to engineer anthrax toxin protective antigen (PrAg), which is proteolytically activated on the cell surface by the proprotein convertase furin to instead be activated by tumor cell-expressed membrane-anchored serine proteases to function as a tumoricidal agent. PrAg's native activation sequence was mutated to a sequence derived from protein C inhibitor (PCI) that can be cleaved by membrane-anchored serine proteases, to generate the mutant protein PrAg-PCIS. PrAg-PCIS was resistant to furin cleavage in vitro, yet cytotoxic to multiple human tumor cell lines when combined with FP59, a chimeric anthrax toxin lethal factor-Pseudomonas exotoxin fusion protein. Molecular analyses showed that PrAg-PCIS can be cleaved in vitro by several serine proteases including the membrane-anchored serine protease testisin, and mediates increased killing of testisin-expressing tumor cells. Treatment with PrAg-PCIS also potently attenuated the growth of testisin-expressing xenograft tumors in mice. The data indicates PrAg can be engineered to target tumor cell-expressed membrane-anchored serine proteases to function as a potent tumoricidal agent.
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Affiliation(s)
- Erik W Martin
- Center for Vascular and Inflammatory Diseases and the Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Marguerite S Buzza
- Center for Vascular and Inflammatory Diseases and the Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kathryn H Driesbaugh
- Center for Vascular and Inflammatory Diseases and the Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Shihui Liu
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yolanda M Fortenberry
- Division of Pediatric Hematology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Stephen H Leppla
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Toni M Antalis
- Center for Vascular and Inflammatory Diseases and the Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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17
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Chen KH, Liu S, Leysath CE, Miller-Randolph S, Zhang Y, Fattah R, Bugge TH, Leppla SH. Anthrax Toxin Protective Antigen Variants That Selectively Utilize either the CMG2 or TEM8 Receptors for Cellular Uptake and Tumor Targeting. J Biol Chem 2016; 291:22021-22029. [PMID: 27555325 DOI: 10.1074/jbc.m116.753301] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Indexed: 11/06/2022] Open
Abstract
The protective antigen (PA) moiety of anthrax toxin binds to cellular receptors and mediates the translocation of the two enzymatic moieties of the toxin to the cytosol. Two PA receptors are known, with capillary morphogenesis protein 2 (CMG2) being the more important for pathogenesis and tumor endothelial marker 8 (TEM8) playing a minor role. The C-terminal PA domain 4 (PAD4) has extensive interactions with the receptors and is required for binding. Our previous study identified PAD4 variants having enhanced TEM8 binding specificity. To obtain PA variants that selectively bind to CMG2, here we performed phage display selections using magnetic beads having bound CMG2. We found that PA residue isoleucine 656 plays a critical role in PA binding to TEM8 but has a much lesser effect on PA binding to CMG2. We further characterized the role of residue 656 in distinguishing PA binding to CMG2 versus TEM8 by substituting it with the other 19 amino acids. Of the resulting variants, PA I656Q and PA I656V had significantly reduced activity on TEM8-expressing CHO cells but maintained their activity on CMG2-expressing CHO cells. The preference of these PA mutants for CMG2 over TEM8 was further demonstrated using mouse embryonic fibroblast cells and mice deficient in the CMG2 and/or the TEM8 receptors. The structural basis of the alterations in the receptor binding activities of these mutants is also discussed.
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Affiliation(s)
- Kuang-Hua Chen
- From the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202 and
| | - Shihui Liu
- From the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202 and the Proteases and Tissue Remodeling Section, Oral and Pharyngeal Cancer Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Clinton E Leysath
- From the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202 and
| | - Sharmina Miller-Randolph
- From the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202 and
| | - Yi Zhang
- From the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202 and
| | - Rasem Fattah
- From the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202 and
| | - Thomas H Bugge
- the Proteases and Tissue Remodeling Section, Oral and Pharyngeal Cancer Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Stephen H Leppla
- From the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202 and
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18
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Abstract
Engineered tumor-targeted anthrax lethal toxin proteins have been shown to strongly suppress growth of solid tumors in mice. These toxins work through the native toxin receptors tumor endothelium marker-8 and capillary morphogenesis protein-2 (CMG2), which, in other contexts, have been described as markers of tumor endothelium. We found that neither receptor is required for tumor growth. We further demonstrate that tumor cells, which are resistant to the toxin when grown in vitro, become highly sensitive when implanted in mice. Using a range of tissue-specific loss-of-function and gain-of-function genetic models, we determined that this in vivo toxin sensitivity requires CMG2 expression on host-derived tumor endothelial cells. Notably, engineered toxins were shown to suppress the proliferation of isolated tumor endothelial cells. Finally, we demonstrate that administering an immunosuppressive regimen allows animals to receive multiple toxin dosages and thereby produces a strong and durable antitumor effect. The ability to give repeated doses of toxins, coupled with the specific targeting of tumor endothelial cells, suggests that our strategy should be efficacious for a wide range of solid tumors.
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19
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An anthrax toxin variant with an improved activity in tumor targeting. Sci Rep 2015; 5:16267. [PMID: 26584669 PMCID: PMC4653645 DOI: 10.1038/srep16267] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 08/20/2015] [Indexed: 12/26/2022] Open
Abstract
Anthrax lethal toxin (LT) is an A-B type toxin secreted by Bacillus anthracis, consisting of the cellular binding moiety, protective antigen (PA), and the catalytic moiety, lethal factor (LF). To target cells, PA binds to cell-surface receptors and is then proteolytically processed forming a LF-binding competent PA oligomer where each LF binding site is comprised of three subsites on two adjacent PA monomers. We previously generated PA-U2-R200A, a urokinase-activated PA variant with LF-binding subsite II residue Arg200 mutated to Ala, and PA-L1-I210A, a matrix metalloproteinase-activated PA variant with subsite III residue Ile210 mutated to Ala. PA-U2-R200A and PA-L1-I210A displayed reduced cytotoxicity when used singly. However, when combined, they formed LF-binding competent heterogeneous oligomers by intermolecular complementation, and achieved high specificity in tumor targeting. Nevertheless, each of these proteins, in particular PA-L1-I210A, retained residual LF-binding ability. In this work, we screened a library containing all possible amino acid substitutions for LF-binding site to find variants with activity strictly dependent upon intermolecular complementation. PA-I207R was identified as an excellent replacement for the original clockwise-side variant, PA-I210A. Consequently, the new combination of PA-L1-I207R and PA-U2-R200A showed potent anti-tumor activity and low toxicity, exceeding the performance of the original combination, and warranting further investigation.
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20
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Andrade BB, Pavan Kumar N, Amaral EP, Riteau N, Mayer-Barber KD, Tosh KW, Maier N, Conceição EL, Kubler A, Sridhar R, Banurekha VV, Jawahar MS, Barbosa T, Manganiello VC, Moss J, Fontana JR, Marciano BE, Sampaio EP, Olivier KN, Holland SM, Jackson SH, Moayeri M, Leppla S, Sereti I, Barber DL, Nutman TB, Babu S, Sher A. Heme Oxygenase-1 Regulation of Matrix Metalloproteinase-1 Expression Underlies Distinct Disease Profiles in Tuberculosis. THE JOURNAL OF IMMUNOLOGY 2015; 195:2763-73. [PMID: 26268658 DOI: 10.4049/jimmunol.1500942] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/15/2015] [Indexed: 01/19/2023]
Abstract
Pulmonary tuberculosis (TB) is characterized by oxidative stress and lung tissue destruction by matrix metalloproteinases (MMPs). The interplay between these distinct pathological processes and the implications for TB diagnosis and disease staging are poorly understood. Heme oxygenase-1 (HO-1) levels were previously shown to distinguish active from latent TB, as well as successfully treated Mycobacterium tuberculosis infection. MMP-1 expression is also associated with active TB. In this study, we measured plasma levels of these two important biomarkers in distinct TB cohorts from India and Brazil. Patients with active TB expressed either very high levels of HO-1 and low levels of MMP-1 or the converse. Moreover, TB patients with either high HO-1 or MMP-1 levels displayed distinct clinical presentations, as well as plasma inflammatory marker profiles. In contrast, in an exploratory North American study, inversely correlated expression of HO-1 and MMP-1 was not observed in patients with other nontuberculous lung diseases. To assess possible regulatory interactions in the biosynthesis of these two enzymes at the cellular level, we studied the expression of HO-1 and MMP-1 in M. tuberculosis-infected human and murine macrophages. We found that infection of macrophages with live virulent M. tuberculosis is required for robust induction of high levels of HO-1 but not MMP-1. In addition, we observed that CO, a product of M. tuberculosis-induced HO-1 activity, inhibits MMP-1 expression by suppressing c-Jun/AP-1 activation. These findings reveal a mechanistic link between oxidative stress and tissue remodeling that may find applicability in the clinical staging of TB patients.
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Affiliation(s)
- Bruno B Andrade
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892; Unidade de Medicina Investigativa, Laboratório Integrado de Microbiologia e Imunorregulação, Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador 40296-710, Brazil;
| | - Nathella Pavan Kumar
- National Institutes of Health, International Center for Excellence in Research, Chennai 600031, India; National Institute for Research in Tuberculosis, Chennai 600031, India
| | - Eduardo P Amaral
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Nicolas Riteau
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Katrin D Mayer-Barber
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Kevin W Tosh
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Nolan Maier
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Elisabete L Conceição
- Unidade de Medicina Investigativa, Laboratório Integrado de Microbiologia e Imunorregulação, Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador 40296-710, Brazil
| | - Andre Kubler
- Department of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | | | | | | | - Theolis Barbosa
- Unidade de Medicina Investigativa, Laboratório Integrado de Microbiologia e Imunorregulação, Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador 40296-710, Brazil
| | - Vincent C Manganiello
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Joel Moss
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Joseph R Fontana
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Beatriz E Marciano
- Immunopathogenesis Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Elizabeth P Sampaio
- Immunopathogenesis Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Kenneth N Olivier
- Immunopathogenesis Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Steven M Holland
- Immunopathogenesis Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Sharon H Jackson
- Division of Intramural Research, National Institute on Minority Health and Health Disparities, National Institutes of Health, Bethesda, MD 20892
| | - Mahtab Moayeri
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Stephen Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Irini Sereti
- Clinical and Molecular Retrovirology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Daniel L Barber
- T-Lymphocyte Biology Unit, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Thomas B Nutman
- Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Subash Babu
- National Institutes of Health, International Center for Excellence in Research, Chennai 600031, India; Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Alan Sher
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
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Bacillus anthracis Overcomes an Amino Acid Auxotrophy by Cleaving Host Serum Proteins. J Bacteriol 2015; 197:2400-11. [PMID: 25962917 DOI: 10.1128/jb.00073-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/21/2015] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Bacteria sustain an infection by acquiring nutrients from the host to support replication. The host sequesters these nutrients as a growth-restricting strategy, a concept termed "nutritional immunity." Historically, the study of nutritional immunity has centered on iron uptake because many bacteria target hemoglobin, an abundant circulating protein, as an iron source. Left unresolved are the mechanisms that bacteria use to attain other nutrients from host sources, including amino acids. We employed a novel medium designed to mimic the chemical composition of human serum, and we show here that Bacillus anthracis, the causative agent of anthrax disease, proteolyzes human hemoglobin to liberate essential amino acids which enhance its growth. This property can be traced to the actions of InhA1, a secreted metalloprotease, and extends to at least three other serum proteins, including serum albumin. The results suggest that we must also consider proteolysis of key host proteins to be a way for bacterial pathogens to attain essential nutrients, and we provide an experimental framework to determine the host and bacterial factors involved in this process. IMPORTANCE The mechanisms by which bacterial pathogens acquire nutrients during infection are poorly understood. Here we used a novel defined medium that approximates the chemical composition of human blood serum, blood serum mimic (BSM), to better model the nutritional environment that pathogens encounter during bacteremia. Removing essential amino acids from BSM revealed that two of the most abundant proteins in blood-hemoglobin and serum albumin-can satiate the amino acid requirement for Bacillus anthracis, the causative agent of anthrax. We further demonstrate that hemoglobin is proteolyzed by the secreted protease InhA1. These studies highlight that common blood proteins can be a nutrient source for bacteria. They also challenge the historical view that hemoglobin is solely an iron source for bacterial pathogens.
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22
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López-Pelegrín M, Ksiazek M, Karim AY, Guevara T, Arolas JL, Potempa J, Gomis-Rüth FX. A novel mechanism of latency in matrix metalloproteinases. J Biol Chem 2015; 290:4728-4740. [PMID: 25555916 DOI: 10.1074/jbc.m114.605956] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The matrix metalloproteinases (MMPs) are a family of secreted soluble or membrane-anchored multimodular peptidases regularly found in several paralogous copies in animals and plants, where they have multiple functions. The minimal consensus domain architecture comprises a signal peptide, a 60-90-residue globular prodomain with a conserved sequence motif including a cysteine engaged in "cysteine-switch" or "Velcro" mediated latency, and a catalytic domain. Karilysin, from the human periodontopathogen Tannerella forsythia, is the only bacterial MMP to have been characterized biochemically to date. It shares with eukaryotic forms the catalytic domain but none of the flanking domains. Instead of the consensus MMP prodomain, it features a 14-residue propeptide, the shortest reported for a metallopeptidase, which lacks cysteines. Here we determined the structure of a prokarilysin fragment encompassing the propeptide and the catalytic domain, and found that the former runs across the cleft in the opposite direction to a bound substrate and inhibits the latter through an "aspartate-switch" mechanism. This finding is reminiscent of latency maintenance in the otherwise unrelated astacin and fragilysin metallopeptidase families. In addition, in vivo and biochemical assays showed that the propeptide contributes to protein folding and stability. Our analysis of prokarilysin reveals a novel mechanism of latency and activation in MMPs. Finally, our findings support the view that the karilysin catalytic domain was co-opted by competent bacteria through horizontal gene transfer from a eukaryotic source, and later evolved in a specific bacterial environment.
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Affiliation(s)
- Mar López-Pelegrín
- From the Proteolysis Lab, Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, c/Baldiri Reixac, 15-21, 08028 Barcelona, Catalonia, Spain
| | - Miroslaw Ksiazek
- the Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Ul. Gronostajowa 7, 30-387 Kraków, Poland, and
| | - Abdulkarim Y Karim
- the Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Ul. Gronostajowa 7, 30-387 Kraków, Poland, and
| | - Tibisay Guevara
- From the Proteolysis Lab, Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, c/Baldiri Reixac, 15-21, 08028 Barcelona, Catalonia, Spain
| | - Joan L Arolas
- From the Proteolysis Lab, Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, c/Baldiri Reixac, 15-21, 08028 Barcelona, Catalonia, Spain,.
| | - Jan Potempa
- the Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Ul. Gronostajowa 7, 30-387 Kraków, Poland, and; the Oral Immunology and Infectious Disease, University of Louisville School of Dentistry, Louisville, Kentucky 40202.
| | - F Xavier Gomis-Rüth
- From the Proteolysis Lab, Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, c/Baldiri Reixac, 15-21, 08028 Barcelona, Catalonia, Spain,.
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23
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Production and cell surface display of recombinant anthrax protective antigen on the surface layer of attenuated Bacillus anthracis. World J Microbiol Biotechnol 2014; 31:345-52. [PMID: 25504373 DOI: 10.1007/s11274-014-1786-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 12/05/2014] [Indexed: 10/24/2022]
Abstract
To investigate the surface display of the anthrax protective antigen (PA) on attenuated Bacillus anthracis, a recombinant B. anthracis strain, named AP429 was constructed by integrating into the chromosome a translational fusion harboring the DNA fragments encoding the cell wall-targeting domain of the S-layer protein EA1 and the anthrax PA. Crerecombinase action at the loxP sites excised the antibiotic marker. Western blot analysis, fluorescence-activated cell sorting and immunofluorescence analysis confirmed that PA was successfully expressed on the S-layer of the recombinant antibiotic marker-free strain. Notwithstanding extensive proteolytic degradation of the hybrid protein SLHs-PA, quantitative ELISA revealed that approximately 8.1 × 10(6) molecules of SLHs-PA were gained from each Bacillus cell. Moreover, electron microscopy assay indicated that the typical S-layer structures could be clearly observed from the recombinant strain micrographs.
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24
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Pasvolsky R, Zakin V, Ostrova I, Shemesh M. Butyric acid released during milk lipolysis triggers biofilm formation of Bacillus species. Int J Food Microbiol 2014; 181:19-27. [PMID: 24801271 DOI: 10.1016/j.ijfoodmicro.2014.04.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 04/03/2014] [Accepted: 04/07/2014] [Indexed: 10/25/2022]
Abstract
Bacillus species form biofilms within milking pipelines and on surfaces of equipment in the dairy industry which represent a continuous hygiene problem and can lead to serious economic losses due to food spoilage and equipment impairment. Although much is known about the mechanism by which the model organism Bacillus subtilis forms biofilms in laboratory mediums in vitro, little is known of how these biofilms are formed in natural environments such as milk. Besides, little is known of the signaling pathways leading to biofilm formation in other Bacillus species, such as Bacillus cereus and Bacillus licheniformis, both of which are known to contaminate milk. In this study, we report that milk triggers the formation of biofilm-related structures, termed bundles. We show this to be a conserved phenomenon among all Bacillus members tested. Moreover, we demonstrate that the tasA gene, which encodes a major portion of the matrix which holds the biofilm together, is vital for this process. Furthermore, we show that the free fatty acid (FFA) - butyric acid (BA), which is released during lipolysis of milk fat and demonstrates antimicrobial activity, is the potent trigger for biofilm bundle formation. We finally show that BA-triggered biofilm bundle formation is mediated by the histidine kinase, KinD. Taken together, these observations indicate that BA, which is a major FFA within milk triggers biofilm formation in a conserved mechanism among members of the Bacillus genus.
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Affiliation(s)
- Ronit Pasvolsky
- Department of Food Quality and Safety, Agricultural Research Organization (ARO), Bet-Dagan, Israel
| | - Varda Zakin
- Department of Food Quality and Safety, Agricultural Research Organization (ARO), Bet-Dagan, Israel
| | - Ievgeniia Ostrova
- Department of Food Quality and Safety, Agricultural Research Organization (ARO), Bet-Dagan, Israel
| | - Moshe Shemesh
- Department of Food Quality and Safety, Agricultural Research Organization (ARO), Bet-Dagan, Israel.
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25
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Cytolethal distending toxin B as a cell-killing component of tumor-targeted anthrax toxin fusion proteins. Cell Death Dis 2014; 5:e1003. [PMID: 24434511 PMCID: PMC4040664 DOI: 10.1038/cddis.2013.540] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 11/27/2013] [Accepted: 12/02/2013] [Indexed: 11/28/2022]
Abstract
Cytolethal distending toxin (Cdt) is produced by Gram-negative bacteria of several species. It is composed of three subunits, CdtA, CdtB, and CdtC, with CdtB being the catalytic subunit. We fused CdtB from Haemophilus ducreyi to the N-terminal 255 amino acids of Bacillus anthracis toxin lethal factor (LFn) to design a novel, potentially potent antitumor drug. As a result of this fusion, CdtB was transported into the cytosol of targeted cells via the efficient delivery mechanism of anthrax toxin. The fusion protein efficiently killed various human tumor cell lines by first inducing a complete cell cycle arrest in the G2/M phase, followed by induction of apoptosis. The fusion protein showed very low toxicity in mouse experiments and impressive antitumor effects in a Lewis Lung carcinoma model, with a 90% cure rate. This study demonstrates that efficient drug delivery by a modified anthrax toxin system combined with the enzymatic activity of CdtB has great potential as anticancer treatment and should be considered for the development of novel anticancer drugs.
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26
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Modulation of the Bacillus anthracis secretome by the immune inhibitor A1 protease. J Bacteriol 2013; 196:424-35. [PMID: 24214942 DOI: 10.1128/jb.00690-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The Bacillus anthracis secretome includes protective antigen, lethal factor, and edema factor, which are the components of anthrax toxin, and other proteins with known or potential roles in anthrax disease. Immune inhibitor A1 (InhA1) is a secreted metalloprotease that is unique to pathogenic members of the Bacillus genus and has been associated with cleavage of host proteins during infection. Here, we report the effect of InhA1 on the B. anthracis secretome. Differential in-gel electrophoresis of proteins present in culture supernatants from a parent strain and an isogenic inhA1-null mutant revealed multiple differences. Of the 1,340 protein spots observed, approximately one-third were less abundant and one-third were more abundant in the inhA1 secretome than in the parent strain secretome. Proteases were strongly represented among those proteins exhibiting a 9-fold or greater change. InhA1 purified from a B. anthracis culture supernatant directly cleaved each of the anthrax toxin proteins as well as an additional secreted protease, Npr599. The conserved zinc binding motif HEXXH of InhA1 (HEYGH) was critical for its proteolytic activity. Our data reveal that InhA1 directly and indirectly modulates the form and/or abundance of over half of all the secreted proteins of B. anthracis. The proteolytic activity of InhA1 on established secreted virulence factors, additional proteases, and other secreted proteins suggests that this major protease plays an important role in virulence not only by cleaving mammalian substrates but also by modulating the B. anthracis secretome itself.
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Sastalla I, Fattah R, Coppage N, Nandy P, Crown D, Pomerantsev AP, Leppla SH. The Bacillus cereus Hbl and Nhe tripartite enterotoxin components assemble sequentially on the surface of target cells and are not interchangeable. PLoS One 2013; 8:e76955. [PMID: 24204713 PMCID: PMC3799921 DOI: 10.1371/journal.pone.0076955] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/28/2013] [Indexed: 02/06/2023] Open
Abstract
Bacillus cereus is a spore-forming, Gram-positive bacterium commonly associated with outbreaks of food poisoning. It is also known as an opportunistic pathogen causing clinical infections such as bacteremia, meningitis, pneumonia, and gas gangrene-like cutaneous infections, mostly in immunocompromised patients. B. cereus secretes a plethora of toxins of which four are associated with the symptoms of food poisoning. Two of these, the non-hemolytic enterotoxin Nhe and the hemolysin BL (Hbl) toxin, are predicted to be structurally similar and are unique in that they require the combined action of three toxin proteins to induce cell lysis. Despite their dominant role in disease, the molecular mechanism of their toxic function is still poorly understood. We report here that B. cereus strain ATCC 10876 harbors not only genes encoding Nhe, but also two copies of the hbl genes. We identified Hbl as the major secreted toxin responsible for inducing rapid cell lysis both in cultured cells and in an intraperitoneal mouse toxicity model. Antibody neutralization and deletion of Hbl-encoding genes resulted in significant reductions of cytotoxic activity. Microscopy studies with Chinese Hamster Ovary cells furthermore showed that pore formation by both Hbl and Nhe occurs through a stepwise, sequential binding of toxin components to the cell surface and to each other. This begins with binding of Hbl-B or NheC to the eukaryotic membrane, and is followed by the recruitment of Hbl-L1 or NheB, respectively, followed by the corresponding third protein. Lastly, toxin component complementation studies indicate that although Hbl and Nhe can be expressed simultaneously and are predicted to be structurally similar, they are incompatible and cannot complement each other.
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Affiliation(s)
- Inka Sastalla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Rasem Fattah
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nicole Coppage
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Poulomi Nandy
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Devorah Crown
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Andrei P. Pomerantsev
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Stephen H. Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
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28
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Leysath CE, Phillips DD, Crown D, Fattah RJ, Moayeri M, Leppla SH. Anthrax edema factor toxicity is strongly mediated by the N-end rule. PLoS One 2013; 8:e74474. [PMID: 24015319 PMCID: PMC3755998 DOI: 10.1371/journal.pone.0074474] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 07/30/2013] [Indexed: 11/29/2022] Open
Abstract
Anthrax edema factor (EF) is a calmodulin-dependent adenylate cyclase that converts adenosine triphosphate (ATP) into 3’–5’-cyclic adenosine monophosphate (cAMP), contributing to the establishment of Bacillus anthracis infections and the resulting pathophysiology. We show that EF adenylate cyclase toxin activity is strongly mediated by the N-end rule, and thus is dependent on the identity of the N-terminal amino acid. EF variants having different N-terminal residues varied by more than 100-fold in potency in cultured cells and mice. EF variants having unfavorable, destabilizing N-terminal residues showed much greater activity in cells when the E1 ubiquitin ligase was inactivated or when proteasome inhibitors were present. Taken together, these results show that EF is uniquely affected by ubiquitination and/or proteasomal degradation.
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Affiliation(s)
- Clinton E. Leysath
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Damilola D. Phillips
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Devorah Crown
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Rasem J. Fattah
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mahtab Moayeri
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Stephen H. Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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29
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Key tissue targets responsible for anthrax-toxin-induced lethality. Nature 2013; 501:63-8. [PMID: 23995686 DOI: 10.1038/nature12510] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/31/2013] [Indexed: 02/01/2023]
Abstract
Bacillus anthracis, the causative agent of anthrax disease, is lethal owing to the actions of two exotoxins: anthrax lethal toxin (LT) and oedema toxin (ET). The key tissue targets responsible for the lethal effects of these toxins are unknown. Here we generated cell-type-specific anthrax toxin receptor capillary morphogenesis protein-2 (CMG2)-null mice and cell-type-specific CMG2-expressing mice and challenged them with the toxins. Our results show that lethality induced by LT and ET occurs through damage to distinct cell types; whereas targeting cardiomyocytes and vascular smooth muscle cells is required for LT-induced mortality, ET-induced lethality occurs mainly through its action in hepatocytes. Notably, and in contradiction to what has been previously postulated, targeting of endothelial cells by either toxin does not seem to contribute significantly to lethality. Our findings demonstrate that B. anthracis has evolved to use LT and ET to induce host lethality by coordinately damaging two distinct vital systems.
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30
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Guevara T, Ksiazek M, Skottrup PD, Cerdà-Costa N, Trillo-Muyo S, de Diego I, Riise E, Potempa J, Gomis-Rüth FX. Structure of the catalytic domain of the Tannerella forsythia matrix metallopeptidase karilysin in complex with a tetrapeptidic inhibitor. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:472-6. [PMID: 23695557 DOI: 10.1107/s1744309113007392] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/18/2013] [Indexed: 01/22/2023]
Abstract
Karilysin is the only metallopeptidase identified as a virulence factor in the odontopathogen Tannerella forsythia owing to its deleterious effect on the host immune response during bacterial infection. The very close structural and sequence-based similarity of its catalytic domain (Kly18) to matrix metalloproteinases suggests that karilysin was acquired by horizontal gene transfer from an animal host. Previous studies by phage display identified peptides with the consensus sequence XWFPXXXGGG (single-letter amino-acid codes; X represents any residue) as karilysin inhibitors with low-micromolar binding affinities. Subsequent refinement revealed that inhibition comparable to that of longer peptides could be achieved using the tetrapeptide SWFP. To analyze its binding, the high-resolution crystal structure of the complex between Kly18 and SWFP was determined and it was found that the peptide binds to the primed side of the active-site cleft in a substrate-like manner. The catalytic zinc ion is clamped by the α-amino group and the carbonyl O atom of the serine, thus distantly mimicking the general manner of binding of hydroxamate inhibitors to metallopeptidases and contributing, together with three zinc-binding histidines from the protein scaffold, to an octahedral-minus-one metal-coordination sphere. The tryptophan side chain penetrates the deep partially water-filled specificity pocket of Kly18. Together with previous serendipitous product complexes of Kly18, the present results provide the structural determinants of inhibition of karilysin and open the field for the design of novel inhibitory strategies aimed at the treatment of human periodontal disease based on a peptidic hit molecule.
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Affiliation(s)
- Tibisay Guevara
- Proteolysis Lab, Molecular Biology Institute of Barcelona, Spanish Research Council CSIC, Barcelona Science Park, c/Baldiri Reixac 15-21, 08028 Barcelona, Catalonia, Spain
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31
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Bezrukov SM, Liu X, Karginov VA, Wein AN, Leppla SH, Popoff MR, Barth H, Nestorovich EM. Interactions of high-affinity cationic blockers with the translocation pores of B. anthracis, C. botulinum, and C. perfringens binary toxins. Biophys J 2013; 103:1208-17. [PMID: 22995493 DOI: 10.1016/j.bpj.2012.07.050] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 07/02/2012] [Accepted: 07/24/2012] [Indexed: 10/27/2022] Open
Abstract
Cationic β-cyclodextrin derivatives were recently introduced as highly effective, potentially universal blockers of three binary bacterial toxins: anthrax toxin of Bacillus anthracis, C2 toxin of Clostridium botulinum, and iota toxin of Clostridium perfringens. The binary toxins are made of two separate components: the enzymatic A component, which acts on certain intracellular targets, and the binding/translocation B component, which forms oligomeric channels in the target cell membrane. Here we studied the voltage and salt dependence of the rate constants of binding and dissociation reactions of two structurally different β-cyclodextrins (AmPrβCD and AMBnTβCD) in the PA(63), C2IIa, and Ib channels (B components of anthrax, C2, and iota toxins, respectively). With all three channels, the blocker carrying extra hydrophobic aromatic groups on the thio-alkyl linkers of positively charged amino groups, AMBnTβCD, demonstrated significantly stronger binding compared with AmPrβCD. This effect is seen as an increased residence time of the blocker in the channels, whereas the time between blockages characterizing the binding reaction on-rate stays practically unchanged. Surprisingly, the voltage sensitivity, expressed as a slope of the logarithm of the blocker residence time as a function of voltage, turned out to be practically the same for all six cases studied, suggesting structural similarities among the three channels. Also, the more-effective AMBnTβCD blocker shows weaker salt dependence of the binding and dissociation rate constants compared with AmPrβCD. By estimating the relative contributions of the applied transmembrane field, long-range Coulomb, and salt-concentration-independent, short-range forces, we found that the latter represent the leading interaction, which accounts for the high efficiency of blockage. In a search for the putative groups in the channel lumen that are responsible for the short-range forces, we performed measurements with the F427A mutant of PA(63), which lacks the functionally important phenylalanine clamp. We found that the on-rates of the blockage were virtually conserved, but the residence times and, correspondingly, the binding constants dropped by more than an order of magnitude, which also reduced the difference between the efficiencies of the two blockers.
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Affiliation(s)
- Sergey M Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.
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Phillips DD, Fattah RJ, Crown D, Zhang Y, Liu S, Moayeri M, Fischer ER, Hansen BT, Ghirlando R, Nestorovich EM, Wein AN, Simons L, Leppla SH, Leysath CE. Engineering anthrax toxin variants that exclusively form octamers and their application to targeting tumors. J Biol Chem 2013; 288:9058-65. [PMID: 23393143 DOI: 10.1074/jbc.m113.452110] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Anthrax toxin protective antigen (PA) delivers its effector proteins into the host cell cytosol through formation of an oligomeric pore, which can assume heptameric or octameric states. By screening a highly directed library of PA mutants, we identified variants that complement each other to exclusively form octamers. These PA variants were individually nontoxic and demonstrated toxicity only when combined with their complementary partner. We then engineered requirements for activation by matrix metalloproteases and urokinase plasminogen activator into two of these variants. The resulting therapeutic toxin specifically targeted cells expressing both tumor associated proteases and completely stopped tumor growth in mice when used at a dose far below that which caused toxicity. This scheme for obtaining intercomplementing subunits can be employed with other oligomeric proteins and potentially has wide application.
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Affiliation(s)
- Damilola D Phillips
- Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, MD 20892, USA
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33
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Wein AN, Liu S, Zhang Y, McKenzie AT, Leppla SH. Tumor therapy with a urokinase plasminogen activator-activated anthrax lethal toxin alone and in combination with paclitaxel. Invest New Drugs 2013; 31:206-12. [PMID: 22843210 PMCID: PMC3757568 DOI: 10.1007/s10637-012-9847-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 06/07/2012] [Indexed: 01/03/2023]
Abstract
PA-U2, an engineered anthrax protective antigen that is activated by urokinase was combined with wildtype lethal factor in the treatment of Colo205 colon adenocarcinoma in vitro and B16-BL6 mouse melanoma in vitro and in vivo. This therapy was also tested in combination with the small molecule paclitaxel, based on prior reports suggesting synergy between ERK1/2 inhibition and chemotherapeutics. Colo205 was sensitive to PA-U2/LF while B16-BL6 was not. For the combination treatment of B16-BL6, paclitaxel showed a dose response in vitro, but cells remained resistant to PA-U2/LF even in the presence of paclitaxel. In vivo, each therapy slowed tumor progression, and an additive effect between the two was observed. Since LF targets tumor vasculature while paclitaxel is an antimitotic, it is possible the agents were acting against different cells in the stroma, precluding a synergistic effect. The engineered anthrax toxin PA-U2/LF warrants further development and testing, possibly in combination with an antiangiogenesis therapy such as sunitinib or sorafinib.
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Affiliation(s)
- Alexander N. Wein
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 33 North Drive, Bethesda, MD, 20892, USA
| | - Shihui Liu
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 33 North Drive, Bethesda, MD, 20892, USA
| | - Yi Zhang
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 33 North Drive, Bethesda, MD, 20892, USA
| | - Andrew T. McKenzie
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 33 North Drive, Bethesda, MD, 20892, USA
| | - Stephen H. Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 33 North Drive, Bethesda, MD, 20892, USA
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34
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Bachran C, Abdelazim S, Fattah RJ, Liu S, Leppla SH. Recombinant expression and purification of a tumor-targeted toxin in Bacillus anthracis. Biochem Biophys Res Commun 2013; 430:150-5. [PMID: 23200832 PMCID: PMC3545075 DOI: 10.1016/j.bbrc.2012.11.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 11/08/2012] [Indexed: 11/22/2022]
Abstract
Many recombinant therapeutic proteins are purified from Escherichia coli. While expression in E. coli is easily achieved, some disadvantages such as protein aggregation, formation of inclusion bodies, and contamination of purified proteins with the lipopolysaccharides arise. Lipopolysaccharides have to be removed to prevent inflammatory responses in patients. Use of the Gram-positive Bacillus anthracis as an expression host offers a solution to circumvent these problems. Using the multiple protease-deficient strain BH460, we expressed a fusion of the N-terminal 254 amino acids of anthrax lethal factor (LFn), the N-terminal 389 amino acids of diphtheria toxin (DT389) and human transforming growth factor alpha (TGFα). The resulting fusion protein was constitutively expressed and successfully secreted by B. anthracis into the culture supernatant. Purification was achieved by anion exchange chromatography and proteolytic cleavage removed LFn from the desired fusion protein (DT389 fused to TGFα). The fusion protein showed the intended specific cytotoxicity to epidermal growth factor receptor-expressing human head and neck cancer cells. Final analyses showed low levels of lipopolysaccharides, originating most likely from contamination during the purification process. Thus, the fusion to LFn for protein secretion and expression in B. anthracis BH460 provides an elegant tool to obtain high levels of lipopolysaccharide-free recombinant protein.
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Affiliation(s)
- Christopher Bachran
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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The receptors that mediate the direct lethality of anthrax toxin. Toxins (Basel) 2012; 5:1-8. [PMID: 23271637 PMCID: PMC3564063 DOI: 10.3390/toxins5010001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 12/19/2012] [Accepted: 12/21/2012] [Indexed: 11/16/2022] Open
Abstract
Tumor endothelium marker-8 (TEM8) and capillary morphogenesis protein-2 (CMG2) are the two well-characterized anthrax toxin receptors, each containing a von Willebrand factor A (vWA) domain responsible for anthrax protective antigen (PA) binding. Recently, a cell-based analysis was used to implicate another vWA domain-containing protein, integrin β1 as a third anthrax toxin receptor. To explore whether proteins other than TEM8 and CMG2 function as anthrax toxin receptors in vivo, we challenged mice lacking TEM8 and/or CMG2. Specifically, we used as an effector protein the fusion protein FP59, a fusion between the PA-binding domain of anthrax lethal factor (LF) and the catalytic domain of Pseudomonas aeruginosa exotoxin A. FP59 is at least 50-fold more potent than LF in the presence of PA, with 2 μg PA + 2 μg FP59 being sufficient to kill a mouse. While TEM8(-/-) and wild type control mice succumbed to a 5 μg PA + 5 μg FP59 challenge, CMG2(-/-) mice were completely resistant to this dose, confirming that CMG2 is the major anthrax toxin receptor in vivo. To detect whether any toxic effects are mediated by TEM8 or other putative receptors such as integrin β1, CMG2(-/-)/TEM8(-/-) mice were challenged with as many as five doses of 50 μg PA + 50 μg FP59. Strikingly, the CMG2(-/-)/TEM8(-/-) mice were completely resistant to the 5-dose challenge. These results strongly suggest that TEM8 is the only minor anthrax toxin receptor mediating direct lethality in vivo and that other proteins implicated as receptors do not play this role.
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Wein AN, Williams BN, Liu S, Ermolinsky B, Provenzano D, Abagyan R, Orry A, Leppla SH, Peredelchuk M. Small molecule inhibitors of Bacillus anthracis protective antigen proteolytic activation and oligomerization. J Med Chem 2012; 55:7998-8006. [PMID: 22954387 DOI: 10.1021/jm300804e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protective antigen (PA), lethal factor, and edema factor, the protein toxins of Bacillus anthracis , are among its most important virulence factors and play a key role in infection. We performed a virtual ligand screen of a library of 10000 members to identify compounds predicted to bind to PA and prevent its oligomerization. Four of these compounds slowed PA association in a FRET-based oligomerization assay, and two of those protected cells from intoxication at concentrations of 1-10 μM. Exploration of the protective mechanism by Western blot showed decreased SDS-resistant PA oligomer on cells and, surprisingly, decreased amounts of activated PA. In vitro assays showed that one of the inhibitors blocked furin-mediated cleavage of PA, apparently through its binding to the PA substrate. Thus, we have identified inhibitors that can independently block both PA's cleavage by furin and its subsequent oligomerization. Lead optimization on these two backbones may yield compounds with high activity and specificity for the anthrax toxins.
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Affiliation(s)
- Alexander N Wein
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 33 North Drive, Bethesda, Maryland 20892, USA
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Arora G, Sajid A, Arulanandh MD, Singhal A, Mattoo AR, Pomerantsev AP, Leppla SH, Maiti S, Singh Y. Unveiling the novel dual specificity protein kinases in Bacillus anthracis: identification of the first prokaryotic dual specificity tyrosine phosphorylation-regulated kinase (DYRK)-like kinase. J Biol Chem 2012; 287:26749-63. [PMID: 22711536 PMCID: PMC3411013 DOI: 10.1074/jbc.m112.351304] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 06/14/2012] [Indexed: 12/23/2022] Open
Abstract
Dual specificity protein kinases (DSPKs) are unique enzymes that can execute multiple functions in the cell, which are otherwise performed exclusively by serine/threonine and tyrosine protein kinases. In this study, we have characterized the protein kinases Bas2152 (PrkD) and Bas2037 (PrkG) from Bacillus anthracis. Transcriptional analyses of these kinases showed that they are expressed in all phases of growth. In a serendipitous discovery, both kinases were found to be DSPKs. PrkD was found to be similar to the eukaryotic dual specificity Tyr phosphorylation-regulated kinase class of dual specificity kinases, which autophosphorylates on Ser, Thr, and Tyr residues and phosphorylates Ser and Thr residues on substrates. PrkG was found to be a bona fide dual specificity protein kinase that mediates autophosphorylation and substrate phosphorylation on Ser, Thr, and Tyr residues. The sites of phosphorylation in both of the kinases were identified through mass spectrometry. Phosphorylation on Tyr residues regulates the kinase activity of PrkD and PrkG. PrpC, the only known Ser/Thr protein phosphatase, was also found to possess dual specificity. Genistein, a known Tyr kinase inhibitor, was found to inhibit the activities of PrkD and PrkG and affect the growth of B. anthracis cells, indicating a possible role of these kinases in cell growth and development. In addition, the glycolytic enzyme pyruvate kinase was found to be phosphorylated by PrkD on Ser and Thr residues but not by PrkG. Thus, this study provides the first evidence of DSPKs in B. anthracis that belong to different classes and have different modes of regulation.
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Affiliation(s)
- Gunjan Arora
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Andaleeb Sajid
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Mary Diana Arulanandh
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Anshika Singhal
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Abid R. Mattoo
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Andrei P. Pomerantsev
- the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202
| | - Stephen H. Leppla
- the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202
| | - Souvik Maiti
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Yogendra Singh
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
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Phase 1 study of a recombinant mutant protective antigen of Bacillus anthracis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 19:140-5. [PMID: 22190398 DOI: 10.1128/cvi.05556-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A phase 1 study of a recombinant mutant protective antigen (rPA) vaccine was conducted in 186 healthy adults aged 18 to 45 years. Volunteers were randomized to receive one of three formulations of rPA (formalin treated, alum adsorbed, or both), in 10- or 20-μg dosages each, or the licensed vaccine, AVA. Three injections were given at 2-month intervals and a 4th 1 year after the 3rd. Vaccinees were examined at the clinic once following each injection, at 48 to 72 h postinjection. Adverse reactions were recorded in diaries for 7 days. Sera were collected before each injection and 1 week after the 1st, 2 weeks after the 3rd and 4th, and 1 year after the 4th. Serum anti-PA IgG was assayed by enzyme-linked immunosorbent assay (ELISA) and toxin neutralization assay (TNA). All formulations at both dosages were safe and immunogenic, inducing booster responses, with the highest antibody levels following the 4th injection (354 to 732 μg/ml). The lowest levels were induced by the formalin-only-treated rPA; there was no statistical difference between levels induced by alum-adsorbed and formalin-treated/alum-adsorbed rPA or by the two dosages. The antibody levels declined in all groups during the 1-year intervals after the 3rd and 4th injections but less so during the 2nd year, after the 4th injection (fold decreases were 10 to 25 versus 3.4 to 7.0, P < 0.001). There were too few AVA recipients for statistical comparisons, but their antibody levels followed those of rPA. Anti-rPA measured by ELISA correlated with TNA titers (r = 0.97). These data support studying alum-adsorbed rPA in children.
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Occurrence, recognition, and reversion of spontaneous, sporulation-deficient Bacillus anthracis mutants that arise during laboratory culture. Microbes Infect 2011; 14:387-91. [PMID: 22166343 DOI: 10.1016/j.micinf.2011.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 11/16/2011] [Accepted: 11/17/2011] [Indexed: 11/22/2022]
Abstract
Bacillus anthracis is a spore-forming, soil-dwelling bacterium. This review describes the occurrence of spontaneous mutations leading to loss of sporulation and the selective pressures that can lead to their enrichment. We also discuss recognition of the associated phenotypes on solid medium, thereby allowing researchers to employ measures that either prevent or favor selection of sporulation-deficient mutants.
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