1
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Hilliard JJ, Jakielaszek C, Mannino F, Hossain M, Qian L, Fishman C, Demons S, Hershfield J, Soffler C, Russo R, Henning L, Novak J, O'Dwyer K. Efficacy of therapeutically administered gepotidacin in a rabbit model of inhalational anthrax. Antimicrob Agents Chemother 2024; 68:e0149723. [PMID: 38358266 PMCID: PMC10916377 DOI: 10.1128/aac.01497-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/17/2024] [Indexed: 02/16/2024] Open
Abstract
Bacillus anthracis is a Gram-positive Centers for Disease Control and Prevention category "A" biothreat pathogen. Without early treatment, inhalation of anthrax spores with progression to inhalational anthrax disease is associated with high fatality rates. Gepotidacin is a novel first-in-class triazaacenaphthylene antibiotic that inhibits bacterial DNA replication by a distinct mechanism of action and is being evaluated for use against biothreat and conventional pathogens. Gepotidacin selectively inhibits bacterial DNA replication via a unique binding mode and has in vitro activity against a collection of B. anthracis isolates including antibacterial-resistant strains, with the MIC90 ranging from 0.5 to 1 µg/mL. In vivo activity of gepotidacin was also evaluated in the New Zealand White rabbit model of inhalational anthrax. The primary endpoint was survival, with survival duration and bacterial clearance as secondary endpoints. The trigger for treatment was the presence of anthrax protective antigen in serum. New Zealand White rabbits were dosed intravenously for 5 days with saline or gepotidacin at 114 mg/kg/d to simulate a dosing regimen of 1,000 mg intravenous (i.v.) three times a day (TID) in humans. Gepotidacin provided a survival benefit compared to saline control, with 91% survival (P-value: 0.0001). All control animals succumbed to anthrax and were found to be blood- and organ culture-positive for B. anthracis. The novel mode of action, in vitro microbiology, preclinical safety, and animal model efficacy data, which were generated in line with Food and Drug Administration Animal Rule, support gepotidacin as a potential treatment for anthrax in an emergency biothreat situation.
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Affiliation(s)
| | | | | | | | - Lian Qian
- GSK, Collegeville, Pennsylvania, USA
| | | | - Samandra Demons
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA
| | - Jeremy Hershfield
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA
| | - Carl Soffler
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA
| | - Riccardo Russo
- Rutgers University School of Medicine, Newark, New Jersey, USA
| | - Lisa Henning
- Battelle Biomedical Research Center (BBRC), Columbus, Ohio, USA
| | - Joseph Novak
- Battelle Biomedical Research Center (BBRC), Columbus, Ohio, USA
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2
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Tessier E, Cheutin L, Garnier A, Vigne C, Tournier JN, Rougeaux C. Early Circulating Edema Factor in Inhalational Anthrax Infection: Does It Matter? Microorganisms 2024; 12:308. [PMID: 38399712 PMCID: PMC10891819 DOI: 10.3390/microorganisms12020308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Anthrax toxins are critical virulence factors of Bacillus anthracis and Bacillus cereus strains that cause anthrax-like disease, composed of a common binding factor, the protective antigen (PA), and two enzymatic proteins, lethal factor (LF) and edema factor (EF). While PA is required for endocytosis and activity of EF and LF, several studies showed that these enzymatic factors disseminate within the body in the absence of PA after intranasal infection. In an effort to understand the impact of EF in the absence of PA, we used a fluorescent EF chimera to facilitate the study of endocytosis in different cell lines. Unexpectedly, EF was found inside cells in the absence of PA and showed a pole-dependent endocytosis. However, looking at enzymatic activity, PA was still required for EF to induce an increase in intracellular cAMP levels. Interestingly, the sequential delivery of EF and then PA rescued the rise in cAMP levels, indicating that PA and EF may functionally associate during intracellular trafficking, as well as it did at the cell surface. Our data shed new light on EF trafficking and the potential location of PA and EF association for optimal cytosolic delivery.
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Affiliation(s)
- Emilie Tessier
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Laurence Cheutin
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Annabelle Garnier
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Clarisse Vigne
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Jean-Nicolas Tournier
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
- Institut Pasteur, 75015 Paris, France
| | - Clémence Rougeaux
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
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3
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Chiang CY, Lane DJ, Zou Y, Hoffman T, Pan J, Hampton J, Maginnis J, Nayak BP, D'Oro U, Valiante N, Miller AT, Cooke M, Wu T, Bavari S, Panchal RG. A Novel Toll-Like Receptor 2 Agonist Protects Mice in a Prophylactic Treatment Model Against Challenge With Bacillus anthracis. Front Microbiol 2022; 13:803041. [PMID: 35369443 PMCID: PMC8965344 DOI: 10.3389/fmicb.2022.803041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/02/2022] [Indexed: 11/23/2022] Open
Abstract
Current therapies for anthrax include the use of antibiotics (i.e., doxycycline, and ciprofloxacin), an anthrax vaccine (BioThrax) and Bacillus anthracis-specific, monoclonal antibody (mAb) (i.e., Raxibacumab and obiltoxaximab). In this study, we investigated the activity of immunomodulators, which potentiate inflammatory responses through innate immune receptors. The rationale for the use of innate immune receptor agonists as adjunctive immunomodulators for infectious diseases is based on the concept that augmentation of host defense should promote the antimicrobial mechanism of the host. Our aim was to explore the anti-B. anthracis effector function of Toll-like receptor (TLR) agonists using a mouse model. Amongst the six TLR ligands tested, Pam3CSK4 (TLR1/2 ligand) was the best at protecting mice from lethal challenge of B. anthracis. We then evaluated the activity of a novel TLR2 ligand, DA-98-WW07. DA-98-WW07 demonstrated enhanced protection in B. anthracis infected mice. The surviving mice that received DA-98-WW07 when re-challenged with B. anthracis 20 days post the first infection showed increased survival rate. Moreover, ciprofloxacin, when treated in adjunct with a suboptimal concentration of DA-98-WW07 demonstrated augmented activity in protecting mice from B. anthracis infection. Taken together, we report the prophylactic treatment potential of DA-98-WW07 for anthrax and the utility of immunomodulators in combination with an antibiotic to treat infections caused by the B. anthracis bacterium.
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Affiliation(s)
- Chih-Yuan Chiang
- Division of Molecular Biology, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Douglas J Lane
- Division of Molecular Biology, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Yefen Zou
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Tim Hoffman
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Jianfeng Pan
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Janice Hampton
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Jillian Maginnis
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Bishnu P Nayak
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Ugo D'Oro
- Novartis Vaccines and Diagnostics, Siena, Italy
| | | | - Andrew T Miller
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Michael Cooke
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Tom Wu
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Sina Bavari
- Division of Molecular Biology, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Rekha G Panchal
- Division of Molecular Biology, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
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4
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Tournier JN, Rougeaux C, Biot FV, Goossens PL. Questionable Efficacy of Therapeutic Antibodies in the Treatment of Anthrax. mSphere 2019; 4:e00282-19. [PMID: 31217301 PMCID: PMC6584371 DOI: 10.1128/msphere.00282-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Inhalational anthrax caused by Bacillus anthracis, a spore-forming Gram-positive bacterium, is a highly lethal infection. Antibodies targeting the protective antigen (PA) binding component of the toxins have recently been authorized as an adjunct to antibiotics, although no conclusive evidence demonstrates that anthrax antitoxin therapy has any significant benefit. We discuss here the rational basis of anti-PA development regarding the pathogenesis of the disease. We argue that inductive reasoning may induce therapeutic bias. We identified anthrax animal model analysis as another bias. Further studies are needed to assess the benefit of anti-PA antibodies in the treatment of inhalational anthrax, while a clearer consensus should be established around what evidence should be proven in an anthrax model.
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Affiliation(s)
- Jean-Nicolas Tournier
- Institut de Recherche Biomédicale des Armées, Bacteriology, Anti-infectious Biotherapies, and Immunity Unit, Brétigny-sur-Orge, France
- Institut Pasteur, Viral Genomics and Vaccination Unit, CNRS UMR-3569, Paris, France
- National Reference Center for Anthrax (CNR-LE Charbon), Brétigny-sur-Orge, France
- Ecole du Val-de-Grâce, Paris, France
| | - Clémence Rougeaux
- Institut de Recherche Biomédicale des Armées, Bacteriology, Anti-infectious Biotherapies, and Immunity Unit, Brétigny-sur-Orge, France
| | - Fabrice V Biot
- Institut de Recherche Biomédicale des Armées, Bacteriology, Anti-infectious Biotherapies, and Immunity Unit, Brétigny-sur-Orge, France
- National Reference Center for Anthrax (CNR-LE Charbon), Brétigny-sur-Orge, France
| | - Pierre L Goossens
- Institut de Recherche Biomédicale des Armées, Bacteriology, Anti-infectious Biotherapies, and Immunity Unit, Brétigny-sur-Orge, France
- Institut Pasteur, Yersinia Unit, Paris, France
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5
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Henning LN, Carpenter S, Stark GV, Serbina NV. Development of Protective Immunity in New Zealand White Rabbits Challenged with Bacillus anthracis Spores and Treated with Antibiotics and Obiltoxaximab, a Monoclonal Antibody against Protective Antigen. Antimicrob Agents Chemother 2018; 62:e01590-17. [PMID: 29133571 PMCID: PMC5786786 DOI: 10.1128/aac.01590-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 11/03/2017] [Indexed: 02/08/2023] Open
Abstract
The recommended management of inhalational anthrax, a high-priority bioterrorist threat, includes antibiotics and antitoxins. Obiltoxaximab, a chimeric monoclonal antibody against anthrax protective antigen (PA), is licensed under the U.S. Food and Drug Administration's (FDA's) Animal Rule for the treatment of inhalational anthrax. Because of spore latency, disease reemergence after treatment cessation is a concern, and there is a need to understand the development of endogenous protective immune responses following antitoxin-containing anthrax treatment regimens. Here, acquired protective immunity was examined in New Zealand White (NZW) rabbits challenged with a targeted lethal dose of Bacillus anthracis spores and treated with antibiotics, obiltoxaximab, or a combination of both. Survivors of the primary challenge were rechallenged 9 months later and monitored for survival. Survival rates after primary and rechallenge for controls and animals treated with obiltoxaximab, levofloxacin, or a combination of both were 0, 65, 100, and 95%, and 0, 100, 95, and 89%, respectively. All surviving immune animals had circulating antibodies to PA and serum toxin-neutralizing titers prior to rechallenge. Following rechallenge, systemic bacteremia and toxemia were not detected in most animals, and the levels of circulating anti-PA IgG titers increased starting at 5 days postrechallenge. We conclude that treatment with obiltoxaximab, alone or combined with antibiotics, significantly improves the survival of rabbits that received a lethal inhalation B. anthracis spore challenge dose and does not interfere with the development of immunity. Survivors of primary challenge are protected against reexposure, have rare incidents of systemic bacteremia and toxemia, and have evidence of an anamnestic response.
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6
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Dawson DG, Bower KA, Burnette CN, Holt RK, Swearengen JR, Dabisch PA, Scorpio A. Using Telemetry Data to Refine Endpoints for New Zealand White Rabbits Challenged with Bacillus anthracis. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2017; 56:792-801. [PMID: 29256375 PMCID: PMC5710159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/07/2017] [Accepted: 09/08/2017] [Indexed: 06/07/2023]
Abstract
We used a continuous-monitoring digital telemetry system to investigate temperature response in New Zealand White rabbits after inhalation or subcutaneous challenge with Bacillus anthracis. Two spore preparations of B. anthracis Ames A2084 were evaluated by using a nose-only inhalation model, and 2 strains, B. anthracis Ames A2084 and B. anthracis UT500, were evaluated in a subcutaneous model. Animal body temperature greater than 3 SD above the mean baseline temperature was considered a significant increase in body temperature (SIBT). All rabbits that exhibited SIBT after challenge by either route of infection or bacterial strain eventually died or were euthanized due to infection, and all rabbits that died or were euthanized due to infection exhibited SIBT during the course of disease. The time at onset of SIBT preceded clinical signs of disease in 94% of the rabbits tested by as long as 2 days. In addition, continuous temperature monitoring facilitated discrimination between the 2 B. anthracis strains with regard to the time interval between SIBT and death. These data suggest that for the New Zealand White rabbit anthrax model, SIBT is a reliable indicator of infection, is predictive of experimental outcome in the absence of treatment, and is measurable prior to the appearance of more severe signs of disease. The use of digital telemetry to monitor infectious disease course in animal models of anthrax can potentially be used in conjunction with other clinical score metrics to refine endpoint euthanasia criteria.
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Affiliation(s)
- David G Dawson
- National Biological Threat Characterization Center, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland
| | - Kristin A Bower
- National Biological Threat Characterization Center, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland
| | - Candace N Burnette
- National Biological Threat Characterization Center, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland
| | - Rebecca K Holt
- National Biological Threat Characterization Center, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland
| | - James R Swearengen
- National Biological Threat Characterization Center, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland
| | - Paul A Dabisch
- National Biological Threat Characterization Center, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland
| | - Angelo Scorpio
- National Biological Threat Characterization Center, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland;,
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7
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Chitlaru T, Israeli M, Rotem S, Elia U, Bar-Haim E, Ehrlich S, Cohen O, Shafferman A. A novel live attenuated anthrax spore vaccine based on an acapsular Bacillus anthracis Sterne strain with mutations in the htrA, lef and cya genes. Vaccine 2017; 35:6030-6040. [DOI: 10.1016/j.vaccine.2017.03.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 01/24/2017] [Accepted: 03/08/2017] [Indexed: 02/06/2023]
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8
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Tao P, Mahalingam M, Zhu J, Moayeri M, Kirtley ML, Fitts EC, Andersson JA, Lawrence WS, Leppla SH, Chopra AK, Rao VB. A Bivalent Anthrax-Plague Vaccine That Can Protect against Two Tier-1 Bioterror Pathogens, Bacillus anthracis and Yersinia pestis. Front Immunol 2017; 8:687. [PMID: 28694806 PMCID: PMC5483451 DOI: 10.3389/fimmu.2017.00687] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 05/26/2017] [Indexed: 01/14/2023] Open
Abstract
Bioterrorism remains as one of the biggest challenges to global security and public health. Since the deadly anthrax attacks of 2001 in the United States, Bacillus anthracis and Yersinia pestis, the causative agents of anthrax and plague, respectively, gained notoriety and were listed by the CDC as Tier-1 biothreat agents. Currently, there is no Food and Drug Administration-approved vaccine against either of these threats for mass vaccination to protect general public, let alone a bivalent vaccine. Here, we report the development of a single recombinant vaccine, a triple antigen consisting of all three target antigens, F1 and V from Y. pestis and PA from B. anthracis, in a structurally stable context. Properly folded and soluble, the triple antigen retained the functional and immunogenicity properties of all three antigens. Remarkably, two doses of this immunogen adjuvanted with Alhydrogel® elicited robust antibody responses in mice, rats, and rabbits and conferred complete protection against inhalational anthrax and pneumonic plague. No significant antigenic interference was observed. Furthermore, we report, for the first time, complete protection of animals against simultaneous challenge with Y. pestis and the lethal toxin of B. anthracis, demonstrating that a single biodefense vaccine can protect against a bioterror attack with weaponized B. anthracis and/or Y. pestis. This bivalent anthrax–plague vaccine is, therefore, a strong candidate for stockpiling, after demonstration of its safety and immunogenicity in human clinical trials, as part of national preparedness against two of the deadliest bioterror threats.
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Affiliation(s)
- Pan Tao
- Department of Biology, The Catholic University of America, Washington, DC, United States
| | - Marthandan Mahalingam
- Department of Biology, The Catholic University of America, Washington, DC, United States
| | - Jingen Zhu
- Department of Biology, The Catholic University of America, Washington, DC, United States
| | - Mahtab Moayeri
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Michelle L Kirtley
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
| | - Eric C Fitts
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
| | - Jourdan A Andersson
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
| | - William S Lawrence
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States.,Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX, United States
| | - Stephen H Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Ashok K Chopra
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States.,Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX, United States.,Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States.,Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX, United States.,Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, United States
| | - Venigalla B Rao
- Department of Biology, The Catholic University of America, Washington, DC, United States
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9
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Booth JL, Duggan ES, Patel VI, Langer M, Wu W, Braun A, Coggeshall KM, Metcalf JP. Bacillus anthracis spore movement does not require a carrier cell and is not affected by lethal toxin in human lung models. Microbes Infect 2016; 18:615-626. [PMID: 27320392 PMCID: PMC5534360 DOI: 10.1016/j.micinf.2016.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 05/04/2016] [Accepted: 06/08/2016] [Indexed: 01/29/2023]
Abstract
The lung is the entry site for Bacillus anthracis in inhalation anthrax, the most deadly form of the disease. Spores escape from the alveolus to regional lymph nodes, germinate and enter the circulatory system to cause disease. The roles of carrier cells and the effects of B. anthracis toxins in this process are unclear. We used a human lung organ culture model to measure spore uptake by antigen presenting cells (APC) and alveolar epithelial cells (AEC), spore partitioning between these cells, and the effects of B. anthracis lethal toxin and protective antigen. We repeated the study in a human A549 alveolar epithelial cell model. Most spores remained unassociated with cells, but the majority of cell-associated spores were in AEC, not in APC. Spore movement was not dependent on internalization, although the location of internalized spores changed in both cell types. Spores also internalized in a non-uniform pattern. Toxins affected neither transit of the spores nor the partitioning of spores into AEC and APC. Our results support a model of spore escape from the alveolus that involves spore clustering with transient passage through intact AEC. However, subsequent transport of spores by APC from the lung to the lymph nodes may occur.
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Affiliation(s)
- J Leland Booth
- Pulmonary and Critical Care Division of the Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Elizabeth S Duggan
- Pulmonary and Critical Care Division of the Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Vineet I Patel
- Pulmonary and Critical Care Division of the Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Marybeth Langer
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
| | - Wenxin Wu
- Pulmonary and Critical Care Division of the Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Armin Braun
- Fraunhofer Institute for Toxicology and Experimental Medicine, D-30625, Hannover, Germany.
| | - K Mark Coggeshall
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
| | - Jordan P Metcalf
- Pulmonary and Critical Care Division of the Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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10
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Obiltoxaximab Prevents Disseminated Bacillus anthracis Infection and Improves Survival during Pre- and Postexposure Prophylaxis in Animal Models of Inhalational Anthrax. Antimicrob Agents Chemother 2016; 60:5796-805. [PMID: 27431219 PMCID: PMC5038297 DOI: 10.1128/aac.01102-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/06/2016] [Indexed: 11/24/2022] Open
Abstract
The Centers for Disease Control and Prevention recommend adjunctive antitoxins when systemic anthrax is suspected. Obiltoxaximab, a monoclonal antibody against protective antigen (PA), is approved for treatment of inhalational anthrax in combination with antibiotics and for prophylaxis when alternative therapies are not available. The impact of toxin neutralization with obiltoxaximab during pre- and postexposure prophylaxis was explored, and efficacy results that supported the prophylaxis indication are presented here. New Zealand White rabbits and cynomolgus macaques received obiltoxaximab as a single intramuscular or intravenous dose of 2 to 16 mg/kg of body weight at various times relative to Bacillus anthracis aerosol spore challenge. The primary endpoint was survival, and effect of treatment timing was explored. In rabbits, obiltoxaximab administration 9 h postchallenge singly or combined with a 5-day levofloxacin regimen protected 89% to 100% of animals compared to 33% with levofloxacin monotherapy. In cynomolgus macaques, a single intramuscular dose of 16 mg/kg obiltoxaximab led to 100% survival when given 1 to 3 days preexposure and 83% to 100% survival when given 18 to 24 h postexposure and prior to systemic bacteremia onset. Obiltoxaximab administration after bacteremia onset resulted in lower (25% to 50%) survival rates reflective of treatment setting. Prophylactic administration of obiltoxaximab before spore challenge or to spore-challenged animals before systemic bacterial dissemination is efficacious in promoting survival, ameliorating toxemia, and inhibiting bacterial spread to the periphery.
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11
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Li Y, Cui X, Xu W, Ohanjanian L, Sampath-Kumar H, Suffredini D, Moayeri M, Leppla S, Fitz Y, Eichacker PQ. Nitric oxide production contributes to Bacillus anthracis edema toxin-associated arterial hypotension and lethality: ex vivo and in vivo studies in the rat. Am J Physiol Heart Circ Physiol 2016; 311:H781-93. [PMID: 27448553 DOI: 10.1152/ajpheart.00163.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 07/19/2016] [Indexed: 01/26/2023]
Abstract
We showed previously that Bacillus anthracis edema toxin (ET), comprised of protective antigen (PA) and edema factor (EF), inhibits phenylephrine (PE)-induced contraction in rat aortic rings and these effects are diminished in endothelial-denuded rings. Therefore, employing rat aortic ring and in vivo models, we tested the hypothesis that nitric oxide (NO) contributes to ET's arterial effects. Compared with rings challenged with PA alone, ET (PA + EF) reduced PE-stimulated maximal contractile force (MCF) and increased the PE concentration producing 50% MCF (EC50) (P < 0.0001). Compared with placebo, l-nitro-arginine methyl-ester (l-NAME), an NO synthase (NOS) inhibitor, reduced ET's effects on MCF and EC50 in patterns that approached or were significant (P = 0.06 and 0.03, respectively). In animals challenged with 24-h ET infusions, l-NAME (0.5 or 1.0 mg·kg(-1)·h(-1)) coadministration increased survival to 17 of 28 animals (60.7%) compared with 4 of 27 (14.8%) given placebo (P = 0.01). Animals receiving l-NAME but no ET all survived. Compared with PBS challenge, ET increased NO levels at 24 h and l-NAME decreased these increases (P < 0.0001). ET infusion decreased mean arterial blood pressure (MAP) in placebo and l-NAME-treated animals (P < 0.0001) but l-NAME reduced decreases in MAP with ET from 9 to 24 h (P = 0.03 for the time interaction). S-methyl-l-thiocitrulline, a selective neuronal NOS inhibitor, had effects in rings and, at a high dose in vivo models, comparable to l-NAME, whereas N'-[3-(aminomethyl)benzyl]-acetimidamide, a selective inducible NOS inhibitor, did not. NO production contributes to ET's arterial relaxant, hypotensive, and lethal effects in the rat.
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Affiliation(s)
- Yan Li
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Xizhong Cui
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Wanying Xu
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Lernik Ohanjanian
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Hanish Sampath-Kumar
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Dante Suffredini
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Mahtab Moayeri
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Stephen Leppla
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Yvonne Fitz
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Peter Q Eichacker
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
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12
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Animal Models for the Pathogenesis, Treatment, and Prevention of Infection by Bacillus anthracis. Microbiol Spectr 2016; 3:TBS-0001-2012. [PMID: 26104551 DOI: 10.1128/microbiolspec.tbs-0001-2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This article reviews the characteristics of the major animal models utilized for studies on Bacillus anthracis and highlights their contributions to understanding the pathogenesis and host responses to anthrax and its treatment and prevention. Advantages and drawbacks associated with each model, to include the major models (murine, guinea pig, rabbit, nonhuman primate, and rat), and other less frequently utilized models, are discussed. Although the three principal forms of anthrax are addressed, the main focus of this review is on models for inhalational anthrax. The selection of an animal model for study is often not straightforward and is dependent on the specific aims of the research or test. No single animal species provides complete equivalence to humans; however, each species, when used appropriately, can contribute to a more complete understanding of anthrax and its etiologic agent.
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13
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Abstract
Anthrax is caused by the spore-forming, gram-positive bacterium Bacillus anthracis. The bacterium's major virulence factors are (a) the anthrax toxins and (b) an antiphagocytic polyglutamic capsule. These are encoded by two large plasmids, the former by pXO1 and the latter by pXO2. The expression of both is controlled by the bicarbonate-responsive transcriptional regulator, AtxA. The anthrax toxins are three polypeptides-protective antigen (PA), lethal factor (LF), and edema factor (EF)-that come together in binary combinations to form lethal toxin and edema toxin. PA binds to cellular receptors to translocate LF (a protease) and EF (an adenylate cyclase) into cells. The toxins alter cell signaling pathways in the host to interfere with innate immune responses in early stages of infection and to induce vascular collapse at late stages. This review focuses on the role of anthrax toxins in pathogenesis. Other virulence determinants, as well as vaccines and therapeutics, are briefly discussed.
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Affiliation(s)
- Mahtab Moayeri
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892; , , , ,
| | - Stephen H Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892; , , , ,
| | - Catherine Vrentas
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892; , , , ,
| | - Andrei P Pomerantsev
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892; , , , ,
| | - Shihui Liu
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892; , , , ,
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14
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Liu T, Warburton RR, Hill NS, Kayyali US. Anthrax lethal toxin-induced lung injury and treatment by activating MK2. J Appl Physiol (1985) 2015; 119:412-9. [PMID: 26066827 DOI: 10.1152/japplphysiol.00335.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 06/10/2015] [Indexed: 11/22/2022] Open
Abstract
Anthrax is associated with severe vascular leak, which is caused by the bacterial lethal toxin (LeTx). Pleural effusions and pulmonary edema that occur in anthrax are believed to reflect endothelial injury caused by the anthrax toxin. Since vascular leak can also be observed consistently in rats injected intravenously with LeTx, the latter might present a simple physiologically relevant animal model of acute lung injury (ALI). Such a model could be utilized in evaluating and developing better treatment for ALI or acute respiratory distress syndrome (ARDS), as other available rodent models do not consistently produce the endothelial permeability that is a major component of ARDS. The biological activity of LeTx resides in the lethal factor metalloprotease that specifically degrades MAP kinase kinases (MKKs). Recently, we showed that LeTx inactivation of p38 MAP kinase signaling via degradation of MKK3 in pulmonary vascular endothelial cells can be linked to compromise of the endothelial permeability barrier. LeTx effects were linked specifically to blocking activation of p38 substrate and MAP kinase-activated protein kinase 2 (MAPKAPK2 or MK2) and phosphorylation of the latter's substrate, heat shock protein 27 (HSP27). We have now designed a peptide that directly and specifically activates MK2, causing HSP27 phosphorylation in cells and in vivo. The MK2-activating peptide (MK2-AP) also blocks the effects of LeTx on endothelial barriers in cultured cells and reduces LeTx-induced pulmonary vascular leak in rats. Hence, MK2-AP has the therapeutic potential to counteract anthrax or pulmonary edema and vascular leak due to other causes.
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Affiliation(s)
- Tiegang Liu
- Pulmonary, Critical Care, and Sleep Division, Department of Medicine/Tupper Research Institute, Tufts Medical Center and Tufts University School of Medicine, Boston, Massachusetts
| | - Rod R Warburton
- Pulmonary, Critical Care, and Sleep Division, Department of Medicine/Tupper Research Institute, Tufts Medical Center and Tufts University School of Medicine, Boston, Massachusetts
| | - Nicholas S Hill
- Pulmonary, Critical Care, and Sleep Division, Department of Medicine/Tupper Research Institute, Tufts Medical Center and Tufts University School of Medicine, Boston, Massachusetts
| | - Usamah S Kayyali
- Pulmonary, Critical Care, and Sleep Division, Department of Medicine/Tupper Research Institute, Tufts Medical Center and Tufts University School of Medicine, Boston, Massachusetts
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15
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Pappas HC, Lovchik JA, Whitten DG. Assessing the Sporicidal Activity of Oligo-p-phenylene Ethynylenes and Their Role as Bacillus Germinants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4481-4489. [PMID: 25822668 DOI: 10.1021/acs.langmuir.5b00064] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A wide range of oligo-p-phenylene ethynylenes has been shown to exhibit good biocidal activity against both Gram-negative and Gram-positive bacteria. While cell death may occur in the dark, these biocidal compounds are far more effective in the light as a result of their ability to sensitize the production of cell-damaging reactive oxygen species. In these studies, the interactions of a specific cationic oligo-p-phenylene ethynylene with spore-forming Bacillus atrophaeus and Bacillus anthracis Sterne have been investigated. Flow cytometry assays are used to rapidly monitor cell death as well as spore germination. This compound effectively killed Bacillus anthracis Sterne vegetative cells (over 4 log reduction), presumably by severe perturbations of the bacterial cell wall and cytoplasmic membrane, while also acting as an effective spore germinant in the dark. While 2 log reduction of B. anthracis Sterne spores was observed, it is hypothesized that further killing could be achieved through enhanced germination.
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Affiliation(s)
- Harry C Pappas
- †The Nanoscience and Microsystems Engineering Program, University of New Mexico, 1 University of New Mexico, Albuquerque, New Mexico 87131-1341, United States
- ‡Center for Biomedical Engineering, Department of Chemical and Biological Engineering, University of New Mexico, 1 University of New Mexico, Albuquerque, New Mexico 87131-1341, United States
| | - Julie A Lovchik
- §Department of Internal Medicine, University of New Mexico Health Sciences Center, 1 University of New Mexico, Albuquerque, New Mexico 87131-1341, United States
| | - David G Whitten
- ‡Center for Biomedical Engineering, Department of Chemical and Biological Engineering, University of New Mexico, 1 University of New Mexico, Albuquerque, New Mexico 87131-1341, United States
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16
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Hutt JA, Lovchik JA, Drysdale M, Sherwood RL, Brasel T, Lipscomb MF, Lyons CR. Lethal factor, but not edema factor, is required to cause fatal anthrax in cynomolgus macaques after pulmonary spore challenge. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:3205-16. [PMID: 25285720 DOI: 10.1016/j.ajpath.2014.08.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 08/01/2014] [Accepted: 08/21/2014] [Indexed: 11/27/2022]
Abstract
Inhalational anthrax is caused by inhalation of Bacillus anthracis spores. The ability of B. anthracis to cause anthrax is attributed to the plasmid-encoded A/B-type toxins, edema toxin (edema factor and protective antigen) and lethal toxin (lethal factor and protective antigen), and a poly-d-glutamic acid capsule. To better understand the contribution of these toxins to the disease pathophysiology in vivo, we used B. anthracis Ames strain and isogenic toxin deletion mutants derived from the Ames strain to examine the role of lethal toxin and edema toxin after pulmonary spore challenge of cynomolgus macaques. Lethal toxin, but not edema toxin, was required to induce sustained bacteremia and death after pulmonary challenge with spores delivered via bronchoscopy. After intravenous challenge with bacilli to model the systemic phase of infection, lethal toxin contributed to bacterial proliferation and subsequent host death to a greater extent than edema toxin. Deletion of protective antigen resulted in greater loss of virulence after intravenous challenge with bacilli than deletion of lethal toxin or edema toxin alone. These findings are consistent with the ability of anti-protective antigen antibodies to prevent anthrax and suggest that lethal factor is the dominant toxin that contributes to the escape of significant numbers of bacilli from the thoracic cavity to cause anthrax after inhalation challenge with spores.
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Affiliation(s)
- Julie A Hutt
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico; Center for Infectious Disease & Immunity, University of New Mexico Health Science Center, Albuquerque, New Mexico.
| | - Julie A Lovchik
- Center for Infectious Disease & Immunity, University of New Mexico Health Science Center, Albuquerque, New Mexico; Department of Internal Medicine, University of New Mexico Health Science Center, Albuquerque, New Mexico
| | - Melissa Drysdale
- Center for Infectious Disease & Immunity, University of New Mexico Health Science Center, Albuquerque, New Mexico; Department of Internal Medicine, University of New Mexico Health Science Center, Albuquerque, New Mexico
| | | | - Trevor Brasel
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Mary F Lipscomb
- Department of Pathology, University of New Mexico Health Science Center, Albuquerque, New Mexico
| | - C Rick Lyons
- Center for Infectious Disease & Immunity, University of New Mexico Health Science Center, Albuquerque, New Mexico; Department of Internal Medicine, University of New Mexico Health Science Center, Albuquerque, New Mexico
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17
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Lowe DE, Ya J, Glomski IJ. In trans complementation of lethal factor reveal roles in colonization and dissemination in a murine mouse model. PLoS One 2014; 9:e95950. [PMID: 24763227 PMCID: PMC3999102 DOI: 10.1371/journal.pone.0095950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 04/02/2014] [Indexed: 12/04/2022] Open
Abstract
Lethal factor (LF) is a component of the B. anthracis exotoxin and critical for pathogenesis. The roles of LF in early anthrax pathogenesis, such as colonization and dissemination from the initial site of infection, are poorly understood. In mice models of infection, LF-deficient strains either have altered dissemination patterns or do not colonize, precluding analysis of the role of LF in colonization and dissemination from the portal of entry. Previous reports indicate rabbit and guinea pig models infected with LF-deficient strains have decreased virulence, yet the inability to use bioluminescent imaging techniques to track B. anthracis growth and dissemination in these hosts makes analysis of early pathogenesis challenging. In this study, the roles of LF early in infection were analyzed using bioluminescent signature tagged libraries of B. anthracis with varying ratios of LF-producing and LF-deficient clones. Populations where all clones produced LF and populations where only 40% of clones produce LF were equally virulent. The 40% LF-producing clones trans complimented the LF mutants and permitted them to colonize and disseminate. Decreases of the LF producing strains to 10% or 0.3% of the population led to increased host survival and decreased trans complementation of the LF mutants. A library with 10% LF producing clones could replicate and disseminate, but fewer clones disseminated and the mutant clones were less competitive than wild type. The inoculum with 0.3% LF producing clones could not colonize the host. This strongly suggests that between 10% and 0.3% of the population must produce LF in order to colonize. In total, these findings suggest that a threshold of LF must be produced in order for colonization and dissemination to occur in vivo. These observations suggest that LF has a major role in the early stages of colonization and dissemination.
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Affiliation(s)
- David E. Lowe
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Jason Ya
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Ian J. Glomski
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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18
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Levy H, Glinert I, Weiss S, Sittner A, Schlomovitz J, Altboum Z, Kobiler D. Toxin-independent virulence of Bacillus anthracis in rabbits. PLoS One 2014; 9:e84947. [PMID: 24416317 PMCID: PMC3885664 DOI: 10.1371/journal.pone.0084947] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 11/14/2013] [Indexed: 12/24/2022] Open
Abstract
The accepted paradigm states that anthrax is both an invasive and toxinogenic disease and that the toxins play a major role in pathogenicity. In the guinea pig (GP) model we have previously shown that deletion of all three toxin components results in a relatively moderate attenuation in virulence, indicating that B. anthracis possesses an additional toxin-independent virulence mechanism. To characterize this toxin-independent mechanism in anthrax disease, we developed a new rabbit model by intravenous injection (IV) of B. anthracis encapsulated vegetative cells, artificially creating bacteremia. Using this model we were able to demonstrate that also in rabbits, B. anthracis mutants lacking the toxins are capable of killing the host within 24 hours. This virulent trait depends on the activity of AtxA in the presence of pXO2, as, in the absence of the toxin genes, deletion of either component abolishes virulence. Furthermore, this IV virulence depends mainly on AtxA rather than the whole pXO1. A similar pattern was shown in the GP model using subcutaneous (SC) administration of spores of the mutant strains, demonstrating the generality of the phenomenon. The virulent strains showed higher bacteremia levels and more efficient tissue dissemination; however our interpretation is that tissue dissemination per se is not the main determinant of virulence whose exact nature requires further elucidation.
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Affiliation(s)
- Haim Levy
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
- * E-mail:
| | - Itai Glinert
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Shay Weiss
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Assa Sittner
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Josef Schlomovitz
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Zeev Altboum
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - David Kobiler
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
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19
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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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20
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Weiner ZP, Ernst SM, Boyer AE, Gallegos-Candela M, Barr JR, Glomski IJ. Circulating lethal toxin decreases the ability of neutrophils to respond toBacillus anthracis. Cell Microbiol 2013; 16:504-18. [DOI: 10.1111/cmi.12232] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 09/24/2013] [Accepted: 10/15/2013] [Indexed: 01/08/2023]
Affiliation(s)
- Zachary P. Weiner
- Department of Microbiology, Immunology, and Cancer Biology; University of Virginia; Charlottesville VA USA
| | - Stephen M. Ernst
- Department of Microbiology, Immunology, and Cancer Biology; University of Virginia; Charlottesville VA USA
| | - Anne E. Boyer
- National Center for Environmental Health; Centers for Disease Control and Prevention; Atlanta GA 30341 USA
| | - Maribel Gallegos-Candela
- National Center for Environmental Health; Centers for Disease Control and Prevention; Atlanta GA 30341 USA
| | - John R. Barr
- National Center for Environmental Health; Centers for Disease Control and Prevention; Atlanta GA 30341 USA
| | - Ian J. Glomski
- Department of Microbiology, Immunology, and Cancer Biology; University of Virginia; Charlottesville VA USA
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21
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Bacillus anthracis has two independent bottlenecks that are dependent on the portal of entry in an intranasal model of inhalational infection. Infect Immun 2013; 81:4408-20. [PMID: 24042112 DOI: 10.1128/iai.00484-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Bacillus anthracis can cause inhalational anthrax. Murine inhalational B. anthracis infections have two portals of entry, the nasal mucosa-associated lymphoid tissue (NALT) and the lumen of the lungs. Analysis of the dissemination from these sites is hindered because infections are asynchronous and asymptomatic until the hosts near death. To further understand and compare how B. anthracis disseminates from these two different environments, clonal analysis was employed using a library of equally virulent DNA-tagged clones of a luminescent Sterne strain. Luminescence was used to determine the origin of the infection and monitor the dissemination in vivo. The number of clones and their proportions in the portals of entry, lymph nodes draining the portals, and kidneys were analyzed. Clonal analysis indicated a bottleneck for both portals of entry, yet the extent and location of the reduction in represented clones differed between the routes. In NALT-based infections, all clones were found to germinate in the NALT, but they underwent a bottleneck as the infection spread to the cervical lymph node. However, lung-based infections underwent a bottleneck in a focal region of growth within the lung lumen and did not need to spread through the mediastinal lymph nodes to cause a systemic infection. Further, the average number of clones found in the kidney and the rate at which genetic drift was affecting the disseminated populations were significantly higher in lung-based infections. Collectively, the data suggested that differences in the host environment alter dissemination of B. anthracis depending on the site of initial colonization and growth.
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22
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Xie T, Sun C, Uslu K, Auth RD, Fang H, Ouyang W, Frucht DM. A New Murine Model for Gastrointestinal Anthrax Infection. PLoS One 2013; 8:e66943. [PMID: 23825096 PMCID: PMC3688947 DOI: 10.1371/journal.pone.0066943] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 05/13/2013] [Indexed: 11/26/2022] Open
Abstract
The scientific community has been restricted by the lack of a practical and informative animal model of gastrointestinal infection with vegetative Bacillus anthracis. We herein report the development of a murine model of gastrointestinal anthrax infection by gavage of vegetative Sterne strain of Bacillus anthracis into the complement-deficient A/J mouse strain. Mice infected in this manner developed lethal infections in a dose-dependent manner and died 30 h-5 d following gavage. Histological findings were consistent with penetration and growth of the bacilli within the intestinal villi, with subsequent dissemination into major organs including the spleen, liver, kidney and lung. Blood cultures confirmed anthrax bacteremia in all moribund animals, with approximately 1/3 showing co-infection with commensal enteric organisms. However, no evidence of immune activation was observed during infection. Time-course experiments revealed early compromise of the intestinal epithelium, characterized by villus blunting and ulceration in the ileum and jejunum. A decrease in body temperature was most predictive of near-term lethality. Antibiotic treatment of infected animals 24 h following high-dose bacterial gavage protected all animals, demonstrating the utility of this animal model in evaluating potential therapeutics.
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Affiliation(s)
- Tao Xie
- Laboratory of Cell Biology, Division of Monoclonal Antibodies, Office of Biotechnology Products, Center for Drug Evaluation and Research, United States Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Chen Sun
- Laboratory of Cell Biology, Division of Monoclonal Antibodies, Office of Biotechnology Products, Center for Drug Evaluation and Research, United States Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Kadriye Uslu
- Laboratory of Cell Biology, Division of Monoclonal Antibodies, Office of Biotechnology Products, Center for Drug Evaluation and Research, United States Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Roger D. Auth
- Laboratory of Cell Biology, Division of Monoclonal Antibodies, Office of Biotechnology Products, Center for Drug Evaluation and Research, United States Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Hui Fang
- Laboratory of Cell Biology, Division of Monoclonal Antibodies, Office of Biotechnology Products, Center for Drug Evaluation and Research, United States Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Weiming Ouyang
- Laboratory of Cell Biology, Division of Monoclonal Antibodies, Office of Biotechnology Products, Center for Drug Evaluation and Research, United States Food and Drug Administration, Bethesda, Maryland, United States of America
| | - David M. Frucht
- Laboratory of Cell Biology, Division of Monoclonal Antibodies, Office of Biotechnology Products, Center for Drug Evaluation and Research, United States Food and Drug Administration, Bethesda, Maryland, United States of America
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23
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St John S, Blower R, Popova TG, Narayanan A, Chung MC, Bailey CL, Popov SG. Bacillus anthracis co-opts nitric oxide and host serum albumin for pathogenicity in hypoxic conditions. Front Cell Infect Microbiol 2013; 3:16. [PMID: 23730627 PMCID: PMC3656356 DOI: 10.3389/fcimb.2013.00016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 04/23/2013] [Indexed: 11/17/2022] Open
Abstract
Bacillus anthracis is a dangerous pathogen of humans and many animal species. Its virulence has been mainly attributed to the production of Lethal and Edema toxins as well as the antiphagocytic capsule. Recent data indicate that the nitric oxide (NO) synthase (baNOS) plays an important pathogenic role at the early stage of disease by protecting bacteria from the host reactive species and S-nytrosylating the mitochondrial proteins in macrophages. In this study we for the first time present evidence that bacteria-derived NO participates in the generation of highly reactive oxidizing species which could be abolished by the NOS inhibitor L - NAME, free thiols, and superoxide dismutase but not catalase. The formation of toxicants is likely a result of the simultaneous formation of NO and superoxide leading to a labile peroxynitrite and its stable decomposition product, nitrogen dioxide. The toxicity of bacteria could be potentiated in the presence of bovine serum albumin. This effect is consistent with the property of serum albumin to serves as a trap of a volatile NO accelerating its reactions. Our data suggest that during infection in the hypoxic environment of pre-mortal host the accumulated NO is expected to have a broad toxic impact on host cell functions.
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Affiliation(s)
- Stephen St John
- National Center for Biodefense and Infectious Diseases, George Mason University Manassas, VA, USA
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24
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Slater LH, Hett EC, Mark K, Chumbler NM, Patel D, Lacy DB, Collier RJ, Hung DT. Identification of novel host-targeted compounds that protect from anthrax lethal toxin-induced cell death. ACS Chem Biol 2013; 8:812-22. [PMID: 23343607 DOI: 10.1021/cb300555n] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Studying how pathogens subvert the host to cause disease has contributed to the understanding of fundamental cell biology. Bacillus anthracis, the causative agent of anthrax, produces the virulence factor lethal toxin to disarm host immunity and cause pathology. We conducted a phenotypic small molecule screen to identify inhibitors of lethal toxin-induced macrophage cell death and used an ordered series of secondary assays to characterize the hits and determine their effects on cellular function. We identified a structurally diverse set of small molecules that act at various points along the lethal toxin pathway, including inhibitors of endocytosis, natural product inhibitors of organelle acidification (e.g., the botulinum neurotoxin inhibitor, toosendanin), and a novel proteasome inhibitor, 4MNB (4-methoxy-2-[2-(5-methoxy-2-nitrosophenyl)ethyl]-1-nitrosobenzene). Many of the compounds, including three drugs approved for use in humans, also protected against the related Clostridium difficile toxin TcdB, further demonstrating their value as novel tools for perturbation and study of toxin biology and host cellular processes and highlighting potential new strategies for intervening on toxin-mediated diseases.
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Affiliation(s)
- Louise H. Slater
- Department of Molecular Biology
and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street,
Boston, Massachusetts 02114, United States
- Infectious Disease Initiative, Broad Institute, 7 Cambridge Center, Cambridge, Massachusetts
02142, United States
- Department
of Microbiology and
Immunobiology, Harvard Medical School,
77 Ave. Louis Pasteur Boston, Massachusetts 02115, United States
| | - Erik C. Hett
- Department of Molecular Biology
and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street,
Boston, Massachusetts 02114, United States
- Infectious Disease Initiative, Broad Institute, 7 Cambridge Center, Cambridge, Massachusetts
02142, United States
- Department
of Microbiology and
Immunobiology, Harvard Medical School,
77 Ave. Louis Pasteur Boston, Massachusetts 02115, United States
| | - Kevin Mark
- Department of Molecular Biology
and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street,
Boston, Massachusetts 02114, United States
- Infectious Disease Initiative, Broad Institute, 7 Cambridge Center, Cambridge, Massachusetts
02142, United States
- Department
of Microbiology and
Immunobiology, Harvard Medical School,
77 Ave. Louis Pasteur Boston, Massachusetts 02115, United States
| | - Nicole M. Chumbler
- Department of Microbiology and
Immunology, Vanderbilt University Medical Center, A-5301 Medical Center North, 1161 21st Avenue South, Nashville,
Tennessee 37232, United States
| | - Deepa Patel
- Department
of Microbiology and
Immunobiology, Harvard Medical School,
77 Ave. Louis Pasteur Boston, Massachusetts 02115, United States
| | - D. Borden Lacy
- Department of Microbiology and
Immunology, Vanderbilt University Medical Center, A-5301 Medical Center North, 1161 21st Avenue South, Nashville,
Tennessee 37232, United States
| | - R. John Collier
- Department
of Microbiology and
Immunobiology, Harvard Medical School,
77 Ave. Louis Pasteur Boston, Massachusetts 02115, United States
| | - Deborah T. Hung
- Department of Molecular Biology
and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street,
Boston, Massachusetts 02114, United States
- Infectious Disease Initiative, Broad Institute, 7 Cambridge Center, Cambridge, Massachusetts
02142, United States
- Department
of Microbiology and
Immunobiology, Harvard Medical School,
77 Ave. Louis Pasteur Boston, Massachusetts 02115, United States
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Göttle M, Dove S, Seifert R. Bacillus anthracis edema factor substrate specificity: evidence for new modes of action. Toxins (Basel) 2012; 4:505-35. [PMID: 22852066 PMCID: PMC3407890 DOI: 10.3390/toxins4070505] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 06/15/2012] [Accepted: 06/27/2012] [Indexed: 12/20/2022] Open
Abstract
Since the isolation of Bacillus anthracis exotoxins in the 1960s, the detrimental activity of edema factor (EF) was considered as adenylyl cyclase activity only. Yet the catalytic site of EF was recently shown to accomplish cyclization of cytidine 5'-triphosphate, uridine 5'-triphosphate and inosine 5'-triphosphate, in addition to adenosine 5'-triphosphate. This review discusses the broad EF substrate specificity and possible implications of intracellular accumulation of cyclic cytidine 3':5'-monophosphate, cyclic uridine 3':5'-monophosphate and cyclic inosine 3':5'-monophosphate on cellular functions vital for host defense. In particular, cAMP-independent mechanisms of action of EF on host cell signaling via protein kinase A, protein kinase G, phosphodiesterases and CNG channels are discussed.
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Affiliation(s)
- Martin Göttle
- Department of Neurology, Emory University School of Medicine, 6302 Woodruff Memorial Research Building, 101 Woodruff Circle, Atlanta, GA 30322, USA
- Author to whom correspondence should be addressed; ; Tel.: +1-404-727-1678; Fax: +1-404-727-3157
| | - Stefan Dove
- Department of Medicinal/Pharmaceutical Chemistry II, University of Regensburg, D-93040 Regensburg, Germany;
| | - Roland Seifert
- Institute of Pharmacology, Medical School of Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany;
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