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Patel VI, Booth JL, Dozmorov M, Brown BR, Metcalf JP. Anthrax Edema and Lethal Toxins Differentially Target Human Lung and Blood Phagocytes. Toxins (Basel) 2020; 12:toxins12070464. [PMID: 32698436 PMCID: PMC7405021 DOI: 10.3390/toxins12070464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/26/2022] Open
Abstract
Bacillus anthracis, the causative agent of inhalation anthrax, is a serious concern as a bioterrorism weapon. The vegetative form produces two exotoxins: Lethal toxin (LT) and edema toxin (ET). We recently characterized and compared six human airway and alveolar-resident phagocyte (AARP) subsets at the transcriptional and functional levels. In this study, we examined the effects of LT and ET on these subsets and human leukocytes. AARPs and leukocytes do not express high levels of the toxin receptors, tumor endothelium marker-8 (TEM8) and capillary morphogenesis protein-2 (CMG2). Less than 20% expressed surface TEM8, while less than 15% expressed CMG2. All cell types bound or internalized protective antigen, the common component of the two toxins, in a dose-dependent manner. Most protective antigen was likely internalized via macropinocytosis. Cells were not sensitive to LT-induced apoptosis or necrosis at concentrations up to 1000 ng/mL. However, toxin exposure inhibited B. anthracis spore internalization. This inhibition was driven primarily by ET in AARPs and LT in leukocytes. These results support a model of inhalation anthrax in which spores germinate and produce toxins. ET inhibits pathogen phagocytosis by AARPs, allowing alveolar escape. In late-stage disease, LT inhibits phagocytosis by leukocytes, allowing bacterial replication in the bloodstream.
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Affiliation(s)
- Vineet I. Patel
- Department of Medicine, Pulmonary, Critical Care & Sleep Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (V.I.P.); (J.L.B.); (B.R.B.)
| | - J. Leland Booth
- Department of Medicine, Pulmonary, Critical Care & Sleep Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (V.I.P.); (J.L.B.); (B.R.B.)
| | - Mikhail Dozmorov
- Department of Biostatistics, Virginia Commonwealth University, Richmond, VA 23298, USA;
| | - Brent R. Brown
- Department of Medicine, Pulmonary, Critical Care & Sleep Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (V.I.P.); (J.L.B.); (B.R.B.)
| | - Jordan P. Metcalf
- Department of Medicine, Pulmonary, Critical Care & Sleep Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (V.I.P.); (J.L.B.); (B.R.B.)
- Department of Microbiology and Immunology, the University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA
- Correspondence:
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Tsilibary EPC, Souto EP, Kratzke M, James LM, Engdahl BE, Georgopoulos AP. Anthrax Protective Antigen 63 (PA63): Toxic Effects in Neural Cultures and Role in Gulf War Illness (GWI). Neurosci Insights 2020; 15:2633105520931966. [PMID: 32656531 PMCID: PMC7328487 DOI: 10.1177/2633105520931966] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/14/2020] [Indexed: 12/11/2022] Open
Abstract
Protective antigen (PA) 63 (PA63) is a protein derived from the PA83 component contained in the anthrax vaccine. The anthrax vaccine ("Biothrax") was administered together with other vaccines to Gulf War veterans, about 35% of whom later developed a multisymptom disease (Gulf War Illness [GWI]), with prominent neurological/cognitive/mood symptoms, among others. The disease has been traditionally attributed to exposures to toxic chemicals during the war but other factors could be involved, including vaccines received. Of these, the anthrax vaccine is the most toxic. Here, we assessed directly the PA63 toxin's harmful effects on cultured neuroblastoma 2A (N2A) cells with respect to cell spreading, process formation, apoptosis, and integrity of cell membrane, cytoskeleton, and mitochondria. We found that, when added in N2A cultures, PA63 toxin led to decreased cell spreading and cell aggregation, leading to apoptosis. The mechanisms of PA63-induced cell damage included compromised cell membrane permeability indicated by enhanced access of propidium iodide in cells. In addition, signaling pathways leading to organization of N2A cytoskeleton were negatively affected, as both actin and microtubular networks were compromised. Finally, the mitochondrial membrane potential was impaired in specific assays. Altogether, these alterations led to apoptosis as a collective toxic effect of PA63 which was substantially reduced by the concomitant addition of specific antibodies against PA63.
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Affiliation(s)
- Effie-Photini C Tsilibary
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN, USA.,Department of Neuroscience, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Eric P Souto
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN, USA
| | - Marian Kratzke
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN, USA.,Department of Neuroscience, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Lisa M James
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN, USA.,Department of Neuroscience, Medical School, University of Minnesota, Minneapolis, MN, USA.,Department of Psychiatry, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Brian E Engdahl
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN, USA.,Department of Neuroscience, Medical School, University of Minnesota, Minneapolis, MN, USA.,Department of Psychology, University of Minnesota, Minneapolis, MN, USA
| | - Apostolos P Georgopoulos
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN, USA.,Department of Neuroscience, Medical School, University of Minnesota, Minneapolis, MN, USA.,Department of Psychiatry, Medical School, University of Minnesota, Minneapolis, MN, USA.,Department of Neurology, Medical School, University of Minnesota, Minneapolis, MN, USA
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Bachran C, Leppla SH. Tumor Targeting and Drug Delivery by Anthrax Toxin. Toxins (Basel) 2016; 8:toxins8070197. [PMID: 27376328 PMCID: PMC4963830 DOI: 10.3390/toxins8070197] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/21/2016] [Accepted: 06/23/2016] [Indexed: 12/17/2022] Open
Abstract
Anthrax toxin is a potent tripartite protein toxin from Bacillus anthracis. It is one of the two virulence factors and causes the disease anthrax. The receptor-binding component of the toxin, protective antigen, needs to be cleaved by furin-like proteases to be activated and to deliver the enzymatic moieties lethal factor and edema factor to the cytosol of cells. Alteration of the protease cleavage site allows the activation of the toxin selectively in response to the presence of tumor-associated proteases. This initial idea of re-targeting anthrax toxin to tumor cells was further elaborated in recent years and resulted in the design of many modifications of anthrax toxin, which resulted in successful tumor therapy in animal models. These modifications include the combination of different toxin variants that require activation by two different tumor-associated proteases for increased specificity of toxin activation. The anthrax toxin system has proved to be a versatile system for drug delivery of several enzymatic moieties into cells. This highly efficient delivery system has recently been further modified by introducing ubiquitin as a cytosolic cleavage site into lethal factor fusion proteins. This review article describes the latest developments in this field of tumor targeting and drug delivery.
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Affiliation(s)
| | - Stephen H Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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Efficacy of Single and Combined Antibiotic Treatments of Anthrax in Rabbits. Antimicrob Agents Chemother 2015; 59:7497-503. [PMID: 26392505 DOI: 10.1128/aac.01376-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/14/2015] [Indexed: 02/07/2023] Open
Abstract
Respiratory anthrax is a fatal disease in the absence of early treatment with antibiotics. Rabbits are highly susceptible to infection with Bacillus anthracis spores by intranasal instillation, succumbing within 2 to 4 days postinfection. This study aims to test the efficiency of antibiotic therapy to treat systemic anthrax in this relevant animal model. Delaying the initiation of antibiotic administration to more than 24 h postinfection resulted in animals with systemic anthrax in various degrees of bacteremia and toxemia. As the onset of symptoms in humans was reported to start on days 1 to 7 postexposure, delaying the initiation of treatment by 24 to 48 h (time frame for mass distribution of antibiotics) may result in sick populations. We evaluated the efficacy of antibiotic administration as a function of bacteremia levels at the time of treatment initiation. Here we compare the efficacy of treatment with clarithromycin, amoxicillin-clavulanic acid (Augmentin), imipenem, vancomycin, rifampin, and linezolid to the previously reported efficacy of doxycycline and ciprofloxacin. We demonstrate that treatment with amoxicillin-clavulanic acid, imipenem, vancomycin, and linezolid were as effective as doxycycline and ciprofloxacin, curing rabbits exhibiting bacteremia levels of up to 10(5) CFU/ml. Clarithromycin and rifampin were shown to be effective only as a postexposure prophylactic treatment but failed to treat the systemic (bacteremic) phase of anthrax. Furthermore, we evaluate the contribution of combined treatment of clindamycin and ciprofloxacin, which demonstrated improvement in efficacy compared to ciprofloxacin alone.
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Kim NY, Kang CI, Hur GH, Yang JM, Shin S. Bacillus anthracis lethal toxin induces cell-type-specific cytotoxicity in human lung cell lines. J Appl Microbiol 2014; 116:1334-43. [PMID: 24471528 DOI: 10.1111/jam.12457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 01/13/2014] [Accepted: 01/23/2014] [Indexed: 12/20/2022]
Abstract
AIMS Inhalational anthrax is caused by the entry of Bacillus anthracis spores into the lung. Inhaled spores are phagocytosed by alveolar macrophages. Bacilli then escape from the macrophage and spread to other cells, initiating a systemic anthrax infection. Based on the pathological studies of primate and human inhalational anthrax cases, it appears that lung tissue injury is a lethal consequence of the disease. Although the cytotoxicity of anthrax lethal toxin to macrophages is well known, it is not clear how anthrax toxin affects the various lung cell types. METHODS AND RESULTS Using model cell lines representing different physiological compartments of the lung, we have investigated the cytotoxic effects of anthrax lethal toxin. The cell response was evaluated through MTT metabolism, neutral red uptake, initiation of apoptosis, and expression and binding activity of anthrax toxin receptors. We found that a human small airway epithelial cell line, HSAEC, was susceptible to anthrax lethal toxin. The other cell lines, A549, MRC-5, H358 and SKLU-1, displayed resistance to anthrax lethal toxin-mediated toxicity, although the expression of anthrax toxin receptors was detected in all the cell lines tested. CONCLUSIONS Our results indicate that cell-type-specific toxicity may be induced by anthrax lethal toxin in human lung tissues and does not correlate with anthrax toxin receptor expression levels. SIGNIFICANCE AND IMPACT OF THE STUDY This work suggests that cell-type-specific cytotoxicity of anthrax toxin in lung cells may cause subsequent lung disease progression. It may explain the initial pathogenic step of inhalational anthrax.
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Affiliation(s)
- N Y Kim
- Department of Life Science, Sogang University, Shinsu-Dong, Mapo, Seoul, Korea
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Salvi M, Sarno S, Cesaro L, Nakamura H, Pinna LA. Extraordinary pleiotropy of protein kinase CK2 revealed by weblogo phosphoproteome analysis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:847-59. [DOI: 10.1016/j.bbamcr.2009.01.013] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 12/22/2008] [Accepted: 01/15/2009] [Indexed: 11/28/2022]
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